003349   MEHRA A, PATRA D S R (Computer Science and Engineering Dep, Bhopal Institute of Technology & Science, Bhopal (M.P.)) : A novel machine learning algorithm for students performance analysis. Curr Trends Biotechnol Pharm 2021, Vol X (1), 979 - 82.

Machine Learning is a field that is used in every system. Machine learning is used in the educational system, in pattern recognition, Games, Industries. In the education system, its importance becomes more because of the future of the students. Education data mining is very useful because the amount of data in the education system increases day by day. Higher education is relatively new, but its importance increases because of the increasing database. There are many approaches to measuring students' performance. K- means is one of the most efficient and used methods. With the help of data mining, the hidden information in the database is getting out, which helps improve students' performance. The decision tree is also a method used to predict the students' performance. Presently, the main problems that educational institutions face are with the growth of data and the need to use this data to enhance the quality. One of the basic techniques often used in analyzing data sets is clustering. This study makes use of cluster analysis to segment students into groups according to their characteristics. An unsupervised algorithm like K-means is discussed. Education data mining is used to study the data available in the education field to bring hidden data, i.e., important and useful information. With the help of these, it is easy to improve the result and future of students.

1 illus, 1 table, 13 ref

003345   PRIYA V (Civil Engineering Dep, B.M.S Coll of Engineering, Bangalore) : Study on the ability of delignified dust particles obtained during separation of coconut fibres, for biogas production and its related chemical kinematics. Asian Jr of Microbiol Biotech Env Sc 2021, Vol 23 (2), 277 - 82.

During the separation of fibers, the dust particles which are also called as coconut coir pith fall away from the husk. This coir pith degrades at a very slow rate. To increase the degradation rate, the coir pith is treated for the reduction in Electrical conductivity and Total dissolved solids .The delignification process is conducted on coir pith to reduce the quantity of lignin present. During the anaerobic treatment of the EC and TDS reduced coir pith, biogas generation has been noticed. This study deals with the determination of the biogas production in the delignified coir pith. There was not a great change in the biogas production in the Delignified, EC & TDS reduced coir pith. It was almost the same as that produced from the EC & TDS reduced coir pith degradation.

19 illus, 1 table, 11 ref

003317   AL-MAMUN1 A, IDRIS A B (Civil Engineering Dep, International Islamic Univ Malaysia, Malaysia) : Anaerobic fluidized bed reactor (AFBR) for the treatment of high solid content agro-industrial wastewater. Asian Jr of Microbiol Biotech Env Sc 2021, Vol 23 (1), 102 - 5.

Palm oil mill effluent (POME) is a high strength agro-industrial wastewater that contains significant amount of organic suspended solids. These solids reduce plant efficiency and account for additional maintenance of fixed bed digesters. An anaerobic fluidized bed reactor was studied to evaluate the performance of the system to treat solids from the POME. The hydraulic retention time (HRT) was reduced step wise from 24 hr to 4 hr, which resulted in volumetric loading rates of 4.0 kg COD/m³ .d to 13.8 kg COD/m³ .d, respectively. The maximum TSS removal rates varied in the range of 68 % - 89 %. The AFBR showed promising performance without exhibiting any problem pertaining to the solids in the wastewater. The AFBR exhibited low sludge production with sludge volume indices (SVI) of between 11 L/mg and 35 L/mg. The low SVI indicates fast settleability and self-compressibility of the digested solid particles in POME. The study showed the superiority of AFBR over the other treatment processes in treating industrial wastewater that contains significant portion of solids.

2 illus, 18 ref

003316   MAMUN A A, RAHMAN M A B A, ALAM M Z, SAYEM S M A (Civil Engineering Dep, International Islamic Univ Malaysia, Malaysia) : Effect of fixed filamentous media on wastewater treatment. Asian Jr of Microbiol Biotech Env Sc 2021, Vol 23 (1), 99 - 101.

Adequate treatment of wastewater is important for the protection of the environment. In many countries, the existing conventional biological wastewater treatment systems are unable to meet the required standards. Therefore, present research focused on the improvement of aerobic wastewater treatment plant by adding readily available cheap media. Plastic filamentous media was used due to the non-biodegradable property. The media length was 5 meter but it was rolled into spiral shape. The average removal of TDS and COD, without the media, was about 35 % and 70 %. After the media has been added, the removal efficiency improved to 55 % and 95 %, respectively. The experimental results demonstrated that the use of filamentous media is capable of improving the quality of effluents in wastewater treatment towards a better quality of effluent to be discharged to nature.

2 illus, 11 ref

003238   KAMOTHI N, THAKUR R (Computer Engineering Dep, Thakur College of Engineering and Technology, Mumbai - 400 101) : Detection of diabetic retinopathy using transfer learning approach. Bioinfolet 2021, 18 (1 A), 51 - 4.

Diabetic retinopathy (DR) is an important cause of Blurred or Impaired vision. It is caused by damage to the blood vessels of the light-sensitive tissue of retina. It is difficult to identify it through retinal images alone. The aim of present investigation was to diagnose the disease using Transfer learning-based algorithm at different levels. Stage classification is a critical step for the assessment and care of DR. We equipped Transfer Learning (TL) based algorithm at different levels.

4 illus, 1 table, 1 ref

003201   NYONI B, TSIPA P, CHIRIRIWA H, HLANGOTHI S (Chemical Engineering Dep, Vaal Univ of Technology, South Africa, Email: harrychiririwa@yahoo.com) : Effects of algal biomass blending on coal decomposition behaviour and kinetics at intermediate pyrolysis regimes. Asian J Chem 2021, 33 (6), 1379 - 84.

Co-pyrolysis of coal with biomass is becoming a popular method of reducing the net carbon dioxide emissions associated with the process. In present work, the pyrolysis of coal and algae was studied using thermogravimetric methods and the kinetics were analyzed using the Coats-Redfern integral method. The kinetics were evaluated for 1^st and 2^nd order reaction models. The effect brought by blending coal with algae on kinetics was studied via the analysis of pyrolysis of different coal-algae blends. The results revealed that the pyrolysis of coal and algae follows 2^nd and 1^st order kinetics with activation energy evaluated in the range 213.4-241.8 and 108.9-122.8 kJ/mol, respectively. It was observed that for coal-algae blending of 20-40 % algae, intermediate pyrolysis, typical heating rates of 50-200 ºC/min was characterized by two distinct stages (ignoring the drying stage) that correspond to the individual decomposition of algae and coal. However, there was an evidence of coal-algae interactions during co-pyrolysis, which made the kinetics of the two distinct stages not to correspond to the kinetics of the individual materials.

3 illus, 4 tables, 37 ref

003198   KULKARNI N, NAVINDAGI M C, KRISHNA M V S M, KUSHNOORE S (Mechanical Engineering Dep, Chaitanya Bharathi Institute of Technology, Hyderabad - 500 075, Email: narasimhaafz@gmail.com) : Green mediated synthesis of macroporous hierarchical CeO₂ nanoparticles using mimosa pudica leaf extract for humidity sensing application. Asian J Chem 2021, 33 (6), 1357 - 62.

Metal oxide nanoparticles are popular candidates for chemiresistive sensors application. Cerium oxide (CeO₂) based semiconducting gas sensors have gained rapid interest in recent years. In this study, an environment-friendly green synthesis approach was employed for the synthesis of macroporous CeO₂ nanoparticles using Mimosa pudica leaf extract. Later the performance of CeO₂ nanoparticles for humidity sensor is demonstrated. X-ray diffraction studies revealed the cubic fluorite crystal structure with no impurities, scanning electron microscopy analysis revealed the macroporous morphology of CeO₂ hierarchical nanoparticles. Humidity sensing properties were studied using interdigitated electrode coated with CeO₂ nanoparticles. The results showed the sensing response of 0.5 times for 10% RH (relative humidity) and seven times for 90% RH. The response and recovery times were found to be as low as 12 s and 15 s, respectively. The experimental results provided an environment-friendly approach for the synthesis of CeO₂ particles and revealed promising results in humidity sensing application.

7 illus, 34 ref

003162   MANURUNG R, SILALAHI H, WINDA O, SIREGAR A G (Chemical Engineering Dep, Univ Sumatera Utara, Indonesia, Email: renita.manurung@usu.ac.id, alwigery10@gmail.com) : Synthesis of 5-hydroxymethylfurfural from cassava (Manihot utilissima pohl) peels through dehydration reaction using deep eutectic solvent based on choline chloride/citric acid. Asian J Chem 2021, 33 (5), 1115 - 9.

The high cellulose content in cassava peel has an opportunity to produce bio-based chemical products in 5-hydroxymethylfurfural (5- HMF) form. This study aimed to determine the optimum conditions of glucose dehydration reaction as a result of hydrolysis of the best cassava peel cellulose. The variables observed in this study were H₂SO₄ catalyst concentrations in the hydrolysis reaction, temperature and amount of deep eutectic solvents based on choline chloride/citric acid. The optimum dehydration reaction conditions in this study was the glucose:deep eutectic solvents mass ratio of 1:6 at the reaction temperature of 80 ºC. The highest yield of 64.50% at an initial glucose concentration of 5.70% using a 1.5% H₂SO₄ catalyst during the hydrolysis of cassava peel cellulose. The results obtained in this study indicated that addition of choline chloride/citric acid as deep eutectic solvent can increase the yield of 5-HMF.

8 illus, 1 table, 37 ref

003153   SANTHOSH C, RAVINDRAN R S E (Electronics and Communication Engineering Dep, Koneru Lakshmaiah Education Foundation, Vaddeswaram - 522 502, Email: ravindran.ernest@gmail.com) : Surface modified chitosan with cadmium sulfide quantum dots as luminescent probe for detection of silver ions. Asian J Chem 2021, 33 (5), 1025 - 30.

In present work, the surface modified cadmium sulfide quantum dots (CdS QDs) was synthesized with chitosan for the detection of silver ions. Chitosan was employed as matrix medium to fabricate CdS QDs, resulting in the formation of novel QDs/chitosan composite. The CdS quantum dots surface coated with chitosan were analyzed using UV-vis spectrophotometer, X-ray diffraction and transmission electron microscope. The chitosan + CdS QDs exhibited high aqueous solubility with better steadiness. By using chitosan + CdS, the silver ions were not only detected but also reduced to nanosize due to the reducing property of chitosan. The mechanism of fluorescence quenching of chitosan + CdS by Ag⁺ was investigated using photoluminescence spectroscopy.

11 illus, 41 ref

003113   AGBOOLA O, ADEDOYIN T, FAYOMI O S I, AYODEJI A, SANNI S E, AYENI A O, POPOOLA P, SADIKU R, ALABA P A, AKANDE G I (Chemical Engineering Dep, Covenant Univ, Indonesia, Email: funmi2406@gmail.com, osfayomi@bellsuniversity.edu.ng) : DNA Inhibition of hydrogen ion-induced corrosion of mild steel used for pipelines in oil and gas industries. Asian J Chem 2021, 33 (4), 767 - 74.

Corrosion of mild steel via chemical reaction in a corrosive environment is a problematic occurrence that is very common in oil and gas industries. Corrosion constitutes a huge part of the total costs in the production of oil and gas. Corrosion inhibitors have found interest in the scientific domain because they are mainly understood by their chemical complexes and formulations. Their utilization in small amount on metal surface used in oil and gas industries can help shield the metal from corrosion devoid of any significant alteration in the concentration of the corrosive media in the environment. An effort was made to study the possibility of using calf thymus gland DNA (CTG_DNA) inhibitor in chlorine induced mild steel for possible usage in piping in oil and gas industry. The SEM micrograph shows that the adsorption of the CTG_DNA biomacromolecules coat on the mild steel surfaces functions as a protection against HCl corrosive solution. Electrochemical study and weight loss analysis showed that the inhibitor efficiency (70.48 and 72%, respectively) of the tested DNA (CTG_DNA) in HCl acidic corrosion environment for the mild steel was high at 1.5 M of HCl. The inhibitor efficiency decreased with increasing HCl concentrations. The open circuit potential (OPC) revealed that the mild steels got corroded until the end of the immersion. The intensities of XRD peak substantiate the existence of corrosion products of FeCl₂.

8 illus, 3 tables, 29 ref

003103   VAIDYANATHAN G S, AISHWARYA B, AHMAD I, SELVAM S P, KUMAR M M, SADIKU E R (Food Process Engineering Dep, SRM Institute of Science and Technology, Kattankulathur - 603 203, Email: periyar.india@gmail.com, periyars@srmist.edu.in) : Review on boosting up body’s natural defence mechanism and suppression of symptoms against SARS-CoV-2 (Covid-19). Asian J Chem 2021, 33 (4), 691 - 700.

The prevailing global health crisis, posed by the pandemic COVID-19, has threatened the livelihood of the public around the world. The dramatic coronavirus surge (2019-nCoV) is denoted as Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). Initially, this deadly ailment was identified to have originated from bats and thereafter, passed on to human beings, in December 2019 via unknown modes of biological transmission in Wuhan, China. One of the leading causes of COVID-19 mortality could be attributed to respiratory failure (hypoxemic or hypercapnic) due to acute respiratory distress. From an immunological perspective, the virus triggers secondary haemophagocytic lymphohistiocytosis, which results in fulminant, followed by fatal hypercytokinaemia alongside multiple organ failure, which happens in adults, in most of the predominant cases. As several scientific communities and researchers, tirelessly strive to find a suitable cure since there is a need for finding a registered medication/vaccine against COVID-19, it becomes quite pertinent for boosting our immune system. As the immune system, supports the body’s ability, as a fortress, to defend against pathogenic microbes, comprising of viruses, fungi, bacteria and protozoan species, thereby restricting infection. This review emphasizes the utilization of naturally-derived or otherwise plant-based supplements/foods that facilitate in enhancing or boosting the immunity against COVID-19, irrespective of one’s age. For a healthy lifestyle, the use of micro and macronutrients, such as: magnesium, zinc, vitamin-rich foods, especially vitamins C, D and E, since health could be enhanced and an individual could be further aided to overcome the infection. This report, majorly investigates the significance of antioxidants and their roles as immune boosters, through determining the various vitamins C and D-rich compounds, alongside the various secondary metabolites-endowed foods from various sources, which could most likely facilitate in improving immunity and thereby, controlling COVID-19.

2 illus, 1 tables, 85 ref

003099   AHABBOUD M, LAMCHARFI T, ABDI F, HADI N, AJYAJE F Z, HADDAD M (Electrical Engineering Dep, Univ Sidi Mohamed Ben Abdellah, Morocco, Email: malikasmp2013@gmail.com, lamcharfi_taj@yahoo.fr) : Effect of Cu doping on structural and dielectric properties of Pb_1-xCu_x(Zr_0.52Ti_0.48)O₃(PC_xZT) (0 ≤ x ≤ 0.2) ceramics prepared by Sol-Gel Method. Asian J Chem 2021, 33 (3), 665 - 70.

In present work, the structural and dielectric properties of Pb_1-xCu_xZr_0.52Ti_0.48O₃ (PC_xZT) ceramics where x = 0. 0.025, 0.05, 0.075, 0.10, 0.15 and 0.20 were studied. Powder of the compositions (PCxZT) was obtained by sol-gel route, the powders were calcined at 700 ºC for 4 h and sintered at 1100 ºC for 4 h. X-ray diffraction analysis and Raman spectroscopy suggest the formation of mixed-phase of tetragonal and rhombohedral structure which was confirmed by Rietveld refinement. Dielectric measurements of the compounds were studied as a function of temperature (from room temperature to 420 ºC at different frequencies) and as a function of frequency (from 100 Hz to 2 MHz at different temperatures). The temperature variation of the real permittivity gives evidence of the ferroelectric phase transition as well as of the resonance behaviour also observed in the dielectric permittivity frequency-dependent variation.

6 illus, 2 tables, 25 ref

003098   CHIRIRIWA H (Chemical Engineering Dep, Vaal Univ of Technology, South Africa, Email: harrychiririwa@yahoo.com) : Characterization of polymer powders and effects of powder reuse in selective laser sintering. Asian J Chem 2021, 33 (3), 658 - 64.

Selective laser sintering (SLS) had been recognized as production expertise (additive manufacturing). The complication restricting the use of SLS in additive manufacturing in an extensive range of industrial scope is the limited selection of usable polymers as it is only limited to polyamide 12. Other polymeric materials such as polypropylene and polyethylene are needed to establish pristine market avenues in industry. In selective laser sintering, the powder is reused in consecutive cycles of the route for the reason that it is sustainable and cost effective. Characterization procedures, including the many available techniques has been proposed to determine changes in chemical microstructures, morphology along with flowability. Subtle disimilarities linking virgin and used powder have been identified through characterization.

14 illus, 41 ref

003093   CHO S K, JUNG J H, SISSEMBAYEVA Y, SONG J H, JUNG D I, HWANG Y H (Nano Energy Engineering Dep, Pusan National Univ, Republic of Korea, Email: yhwang@pusan.ac.kr) : Microwave assisted synthesis of dibenzo-[b,f][1,5]diazocine derivatives for photocatalytic water splitting applications. Asian J Chem 2021, 33 (3), 627 - 31.

Photocatalytic water splitting converts solar energy to storable hydrogen molecules which has the highest energy per mass. Most catalysts for photocatalytic water splitting utilize noble metals or precious metals. Organic photocatalysts are attracting more attention owing to several advantages like light weight, low cost, defined structure and tunability. In this study, the synthesis of several dibenzo[b,f][1,5]- diazocines via microwave irradiation for water splitting application is reported. Microwave irradiation facilitates fast, safe and simple synthesis in green reaction conditions. Mini library of dibenzo[b,f][1,5]diazocines were created in order to understand substituents effect on the photocatalytic activity.

4 illus, 1 table, 18 ref

000793   ATHIRA G, BAHURUDEEN A, APPARI S (Civil Engineering Dep, Birla Institute of Technology and Science, Hyderabad- 500 078, Email: bahurudeen.civil@gmail.com) : Thermochemical conversion of sugarcane bagasse: Composition, reaction kinetics, and characterisation of by-products. Sugar Tech 2021, 23(2), 433–52.

Sugarcane bagasse pyrolysis is an effective way of producing renewable and sustainable energy. A combined study on characterisation of primary and secondary by-products of sugarcane towards the effective use of bagasse as an energy feedstock and biochar is not yet available in the existing literature. This study is an attempt to bridge this gap and to understand the complete valorisation potential of sugarcane bagasse and its by-products. In this study, the elemental, structural, and compositional analyses of sugarcane bagasse collected from various sources were carried out, and their thermal decomposition behaviour under pyrolysis conditions was investigated using thermogravimetric data. The composition of all sugarcane bagasse samples showed remarkable similarity, except for the presence of high soluble sugars in two of the six samples. The hemicellulose content in the lignocellulosic bagasse samples was found to have a distinct thermal decomposition pattern, resulting in deconvolved derivative thermogravimetric curves with peaks centred at around 300 ^oC. A detailed analysis of the thermogravimetric data indicated a complex multi-step thermal degradation behaviour for bagasse under pyrolysis conditions. The pyrolysis reaction kinetics of sugarcane bagasse were developed by using iso-conversional and model-fitting methods. Further, SEM–EDS analysis revealed that the biochar obtained from bagasse fast pyrolysis experiments was predominantly siliceous. X-ray diffraction studies on biochar indicated that there were no crystalline phases, even at pyrolysis temperature of 700 ^oC.

19 illus, 6 tables, 48 ref

000787   KUMAR D S S, CHETHAN K, KUMAR B C (Civil Engineering Dep, People’s Education Society, Karnataka- 571 401, Email: chethan.1911@gmail.com) : Effect of elevated temperatures on sugarcane bagasse ash-based alkali-activated slag concrete. Sugar Tech 2021, 23(2), 369–81.

The main focus of researchers in construction sector is to check suitability of ecofriendly alternative materials. Sugarcane bagasse ash (BA) and steel slag (SS) is one among such ecofriendly alternative materials. BA and SS has potential to utilize as binder and coarse aggregate, respectively, in concrete production. In the present investigation, BA and SS were utilized in alkaliactivated slag/bagasse ash concrete (AASBC) mixture production. Full factorial experimental design was considered with two input variables, i.e., BA (0, 25, and 50 %) and SS (0, 50, and 100 %) as replacement to ground granulated blast furnace slag and natural coarse aggregate, respectively. Effect of elevated temperatures on BA and SS-based AASBC mixture were examined. Field emission scanning electron microscope study were carried out to check the morphological changes in ambient and elevated temperature condition. In order to rank different BA and SS-based AASBC mixture performance multi-criteria optimization techniques like, grey relational analysis, technique for order preference by similarity to ideal solution, and desirability function approach were utilized. AASBC mixture with 25 % BA content and 100% SS content found to be most suitable AASBC mixture based on multi-criteria optimization technique under elevated temperature conditions.

3 illus, 11 tables, 48 ref

000760   NARDO L A S, PAIXAO (Engineering and Exact Sciences Dep, Sao Paulo State Univ, Sao Paulo, Brazil, Email: alexgonzaga.agr@gmail.com) : Software optimisation for mechanised sugarcane planting scenarios to aid in decision-making. Sugar Tech 2021, 23(1), 86-93.

With advancements in the mechanisation of sugarcane farming, studies have been fundamental to improving the process—from soil preparation to harvest. Faced with increasing challenges of economic scenarios, alternatives should be sought aimed at optimising resources, reducing costs, improving operational efficiency, logistics, among others. Planting is one of the main agricultural operations, any deviation in this phase harms the crop during the crop cycle, so planning in advance the area to be planted is essential for better results. Analysis of better planting scenarios prior to harvest combined with the use of autopilot requires knowledge of the systematisation areas and skilled labour to guarantee the quality of the process and reduce losses and damages. The objective of this study is to both evaluate and optimise sugarcane planting scenarios based on travel and manoeuvre time, travel distance, number of manoeuvres, and fuel consumption. The study was conducted in the municipality of Tanabi, SP, during the 2013 planting season. The results showed fewer manoeuvres and longer planting lines in the optimised area, increased the availability of the machine and generated possible cost reduction.

5 illus, 2 table, 20 ref

000752   CORREDO L P, CANATA T F, MALDANER L F, LIMA J J A, MOLIN J P (Biosystems Engineering Dep, Sao Paulo Univ, Sao Paulo 13418-900, Brazil, Email: lucaspcorredo@usp.br) : Sugarcane harvester for in-field data collection: state of the art, its applicability and future perspectives. Sugar Tech 2021, 23(1), 1-14.

Sugarcane harvesters have a high level of embedded technology and the opportunity to expand applications to become an important high-density data collection machine. The acquired data, such as yield, losses, and quality, would provide valuable information for site-specific management of sugarcane. This review describes the current instrumentation used by sugarcane harvesters to map yield with the current technologies that have the highest potential applications for losses and quality mapping. In sugarcane cultivation, the harvester cuts and processes the product along a single or double row, which makes it easier to evaluate yield, losses, and quality at the row level. However, studies that explore the holistic potential of the sensors and data processing from the harvester for within-row detailed spatial information are scarce. Over the years, several studies focused on sugarcane yield mapping; however, yield monitors are far from being popular among sugarcane producers due to its low accuracy. Yield monitors need to be robust and accurate; the data generated from default factory-installed sensors is a potential alternative to improve data collection. Also, the integration of the current data available on the harvesters and the use of sensors to estimate sugarcane parameters (i.e., yield, losses, and quality) may represent an important advance in the agricultural operations. This article provides some information regarding the automation of the machines and the operational improvements, such as logistics planning and machine performance..

4 illus, 5 tables, 93 ref

000474   RATHOD M S, RATHOD B M (Sant Longowal Institute of Engineering and Technology, Longowal, Punjab) : Comparative study of effect of frying temperature and hydrocolloid treatment on color and sensory characteristics of banana chips. J Pharma Innov 2021, 10(2), 144-9.

The present investigation for screening of banana (Musa paradisica) cultivars for preparation of banana chips and snacks was carried out to standardized the process for preparation of banana chips and selection of good cultivars for production of Banana chips. Three cultivars VIZ. Ardhapuri, Grand naine and Mahalakshmi were selected for screening for preparation of banana chips and snacks. Further, these samples were evaluated for their physico-chemical, textural characterstics and sensory qualities. Banana slices were fried at different temperature ie. 145 oC, 160 oC and 175 oC for the period of 6 min., 4 min. and 3 min. respectively. The best result was obtained at temperature 160 oC for the period of 4 minutes. At this temperature banana slices were yellowish in colour. Hence this temperature time combination was used for further process. Three hydrocolloids were used for hydrocolloid treatments VIZ. Sodium alginate, CMC (Carboxy methyl cellulose) and Pectin were used for three different banana cultivar. Each cultivar was treated with these hydrocolloids. From each cultivar there was one sample selected for further studies. Sample C which treated with CMC from Ardhapuri cultivar, sample D which treated with pectin from Grand naine cultivar and sample C which treated with CMC from Mahalakshmi cultivar were selected. Again these three samples were evaluated for sensory characteristics.

4 illus, 6 tables, 9 ref

000714   MOHAMMED J, BINDU S S, MOHIZIN A, ROY K E R (Mechanical Engineering Dep, TKM Coll of Engineering, Kollam- 691 005, Email: jesnamohammed@tkmce.ac.in) : Experimental investigation on heat transfer characteristics in cryogenic chilldown of a helically coiled tube. Sadhana 2021, 46, 2.

Chilldown of transfer lines is an important phenomenon associated with cryogenic liquid transfer from the storage facility to the location of its intended application. Analysis of heat transfer characteristics during cryogenic chilldown of a helical coil is the focus of this study. In view of the ease in availability and handling compared to other cryogens, Liquid nitrogen is adopted. The cryogen was transmitted through copper helical test sections with 7.94 mm outer diameter, 0.81 mm wall thickness and having helix angles 4, 6, 8, 10, 12 and 16 with horizontal axes, at three different mass fluxes, that is, 66 kg/m²s, 86 kg/m²s and 102 kg/ m²s under terrestrial gravity conditions. Temperature-time relationships were obtained and the results were compared with that of straight channels. The results of the experiment indicated that the chilldown time for coils of different helix angles were different at a given mass flux. Also, for a given helix angle, chilldown time varied inversely with mass flux. Results suggested the prospect of an optimum helix angle that can serve in minimizing the chilldown time, thereby reducing cryogenic liquid consumption. Finding correlations connecting heat transfer parameters in helical coils would enhance the scope of this study.

11 illus, 42 ref

000713   AGRAWAL V, GAUTAM S S (Mechanical Engineering Dep, Indian Institute of Technology, Guwahati- 781 039, Email: v.agrawal@iitg.ac.in) : NURBS-based isogeometric analysis for stable and accurate peeling computations. Sadhana 2021, 46, 3.

Numerical solution of adhesive peeling problems presents significant computational challenges. This is due to the large peeling stresses that occur in the very narrow zone ahead of the peeling front. The available literature offers solutions using either higher-order Lagrange-enriched finite-element (FE) or nonuniform rational B-spline (NURBS)-enriched FE strategies. However, no work that fully utilizes the intrinsic advantageous features of isogeometric analysis and systemically explores the influence of NURBS discretizations exists on the adhesive peeling computations. Thus, the objective of the present work is to fill this research gap by carrying out a comprehensive and detailed isogeometric analysis of peeling problems and also to study the effect of different classes of NURBS discretizations on the stability and accuracy of peeling contact computations. In particular, higher-continuous and higher-order NURBS discretizations that are constructed with different combinations of various isogeometric refinement strategies are employed. In addition to this, higher-order Lagrange discretizations are adopted to perform comparative assessment of various isogeometric NURBS discretizations. The comparison is carried out in terms of accuracy, stability and computation cost for peeling analysis. The obtained results demonstrate the advantages of the NURBS discretizations: higher-continuous NURBS discretization delivers an accuracy similar to that with the higher-order Lagrange discretization at a much lower computational cost. Further, the higher-order NURBS discretizations significantly improve the stability and accuracy again at a lower computational cost as compared with higher-order Lagrange discretizations.

9 illus, 3 tables, 37 ref

000712   MUTLU H (Mechanical Engineering Dep, Mersin Univ, Mersin, Turkey, Email: huseyinmutlu@yahoo.com) : Design of the crank–rocker mechanism for various design cases based on the closed-form solution. Sadhana 2021, 46, 4.

The problem of motion transformation from a complete rotation into an oscillatory motion is seen in many applications, and the simplest solution to this problem is possible with the design of a crank–rocker mechanism. In this study the design of the crank–rocker mechanism in the analytical method, based on a closedform solution, has been achieved according to several requirements that may arise by the designers for specific design cases, considering all the effective design parameters of the crank–rocker mechanism. Besides, numerical examples are presented with the help of a computer program developed using the obtained design equations.

8 illus, 6 tables, 24 ref

000711   SARKER B, CHAKRABORTY S (Production Engineering Dep, Jadavpur Univ, Kolkata, West Bengal, Email: s_chakraborty00@yahoo.co.in) : Structural equation modeling-based performance estimation and parametric analysis of wire electrical discharge machining processes. Sadhana 2021, 46, 5.

This paper deals with development of structural equation models for two wire electrical discharge machining (WEDM) processes so as to investigate and estimate their machining performance along with identification of the most significant input parameters influencing the operational achievement of the said processes. These models also search out the corresponding responses to be treated as the best performance indicators for both the WEDM processes. Based on the experimental and simulated datasets, two models are subsequently developed showing the relationships between the input parameters, responses and machining performance for each of the considered WEDM processes. For both the processes, it is observed that the second model, developed without considering the insignificant input parameters, has better goodness-of-fit value as compared to the first model where all the WEDM process parameters are contemplated as the predictor variables. It can be revealed that pulse-on time is the most important predictor of machining performance with standardized coefficients of 0.61 and 0.75 respectively for the two WEDM processes. Machining rate acts as the main indicator variable in the first experimental dataset, while gap current is the most significant indicator variable in the second experimental dataset with factor loadings of 0.98 and 0.92 respectively.

8 illus, 14 tables, 28 ref

000706   DEMIRIZ A O, BAYRAK O U, BAYATA H F (Civil Engineering Dep, Erzincan Binali Yildirim Univ, Erzincan, Turkey, Email: ahmet.demiriz@erzincan.edu.tr) : Corridor capacity analysis with mesoscopic simulation: Erzincan province sample. Sadhana 2021, 46, 10.

Today, the existing traffic networks cannot cope-up with the increasing transportation demands and traffic volume and fail to meet the demands. This causes economic and social losses. Increasing transportation demands and traffic volume in Erzincan city center of Turkey cause the main arteries and junctions to be insufficient. In such problems, solutions are generally produced using parameters such as trip and delay durations and exhaust emissions. Another point to be considered is to ensure the improved intersections to work as a whole. In this study, the main arteries and the junctions on these in Erzincan city center were discussed. In this context, totally 14 intersections were tried to be improved. Suggestions were offered regarding delay time, travel time, queue lengths, NO_x and CO₂ emissions, and average speed values as the design criteria. Simulations were made in AIMSUN program for the current situation and four different scenarios. Analytical Hierarchy Process (AHP), which is one of the multi-criteria decision-making methods for the network was employed to determine which scenario was more appropriate. At the end of the study, decrease of up to 23 % for travel time, 47 % for delays, 48 % for queue lengths, 11 % for NOx, and 13 % for CO₂ and increase of up to 30 % in average speed were obtained. According to AHP, Scenario 4 had the highest priority value among all alternatives. Moreover, the reliability of the results was ensured by supporting the mesoscopic simulation with AHP which is a multi-criteria decision-making method.

13 illus, 4 tables, 39 ref

000705   PATIL C S, ANSARI M I,SELVAN R, THAKUR D G (Mechanical Engineering Dep, Defence Institute of Advanced Technology, Maharashtra- 411 025, Email: patilchetan2007@gmail.com) : Influence of micro B₄C ceramic particles addition on mechanical and wear behavior of aerospace grade Al-Li alloy composites. Sadhana 2021, 46, 11.

Aluminum matrix composites are being widely used in aircrafts due to high strength to weight ratio, good tribological properties and better castability. The B₄C particles have low density, high hardness, high strength and stiffness. The poor wettability is major challenge during the fabrication of Al-B₄C composite. To overcome this problem, titanium based flux (K₂TiF₆) was used to improve the wettability. In this study, structurally efficient Al-Li 8090 alloy containing 2, 5 and 10 wt % of B₄C particles were fabricated by using modified stir casting technique with an objective to obtain homogenous dispersion of B₄C particles in the matrix. The microstructures evaluation was done to know the distribution of particulates in the matrix. The influence of particle volume content on the mechanical and wear behavior of composites has been investigated. The ultimate tensile strength, micro and macro hardness, high temperature hardness and wear characteristics have been investigated. Ageing behavior, XRD analysis and fractography of the composites has also been studied. The outcome of the experimental investigation revealed that, 2 % B₄C particulate reinforced composite exhibits better mechanical, physical and tribological properties. 10 % B₄C particulate reinforced composite shows clustering and agglomeration at some local regions causing a drop in the properties.

12 illus, 6 tables, 19 ref

000704   GOUTHAM V, HARIGOVINDAN V P (Electronics and Communication Engineering Dep, National Institute of Technology, Karaikal- 609 609, Email: gouthamveerapu@gmail.com) : Stochastic modelling and performance analysis of cooperative HARQ in multi-cluster underwater acoustic sensor networks. Sadhana 2021, 46, 12.

Cooperative hybrid automatic repeat request (C-HARQ) scheme based on multi-hop relaying has been adopted as an efficient strategy in underwater acoustic sensor networks (UASNs) to extend network coverage and to enhance the performance by utilizing spatial diversity gain. In this letter, we develop a stochastic model for multi-cluster transmissions in UASNs, considering the underwater-specific characteristics such as frequency-dependent signal attenuation, acoustic spreading, multi-path fading and underwater noises. From this generalized stochastic model, we derive accurate analytical expressions to analyse the end-to-end packet error rate (PER) and energy efficiency. Analytical results demonstrate that the C-HARQ scheme can significantly improve the performance of UASNs, especially with the increase in number of relay nodes. Analytical results are corroborated with extensive simulation studies.

2 illus, 2 tables, 12 ref

000703   SAHOO C K, MALLICK S, KUMAR K, MASANTA M (Mechanical Engineering Dep, National Institute of Technology, Rourkela- 769 008, Email: manoj.masanta@gmail.com) : Pulse laser welding of high carbon alloy steel: assessment of melt pool geometry and mechanical performance. Sadhana 2021, 46, 13.

An attempt has been made to join high carbon alloy steel sheet of 0.9 mm thickness by pulse Nd:YAG laser beam welding. Weld melt-pool geometry (i.e., melting depth and width) and the microstructure of the weld zone was analyzed through the optical microscopic images. The tensile strength of the weld joint was assessed through a universal testing machine. The variation of microhardness value in the melt pool zone of the weldment was assessed through Vickers micro indentation method. The effect of laser peak power and scan speed on the melt pool geometry, microstructure, tensile strength, and microhardness value of the weld joint was explored. The outcomes indicated that within the experimental domain for an optimum processing condition (laser peak power: 5 kW, beam diameter: 0.7 mm, pulse duration: 7 ms, and pulse frequency: 5 Hz), full penetrated welding was achieved, which exhibited almost 85 % of the base material strength.

7 illus, 24 ref

000702   BABU D L, SREENIVASULU T (Electronics and Communication Engineering Dep, SRM Univ, Neerukonda- 522 502, Email: enin_dhandrapati@srmap.edu.in) : 4-Channel DWDM demultiplexer on silicon photonic crystal slab. Sadhana 2021, 46, 14.

A novel DWDM device based on Silicon Photonic Crystal (PC) slab is proposed. Hexagonal ring resonators are used for channel dropping purpose. Channel dropping is achieved by fine tuning of lattice constant inside the ring resonators. The device is designed in such a way that the demultiplexed wavelengths are in C band of electromagnetic spectrum where EDFA is applicable. An average channel spacing of 0.8 nm is obtained and the maximum cross talk between the adjacent channels is found to be a fraction of 0.07 of the applied input intensity. The coupling efficiency of the input power to the channels is observed to be 60 %. Approximate footprint of the device is found to be 475 lm² .

7 illus, 1 table, 19 ref

000701   MUJEEB S M, SAM R P, MADHAVI K (CSE Dep, Jawaharlal Nehru Technological Univ, Ananthapuramu- 515 002, Email: mujeeb.smd@gmail.com) : Adaptive Exponential Bat algorithm and deep learning for big data classification. Sadhana 2021, 46, 15.

The concept of big data refers to the huge amount of information that the organizations process, analyse and store. In the real-world scenario, some big data possess other features such as credit card fraud detection big data, extreme weather forecast big data and so on. In order to deal with the problem of classifying the binary imbalanced big data, based on MapReduce framework (MRF), an enhanced model is proposed for the process of classification in this paper. An optimization based on MRF is used for dealing with the imbalanced big data using the deep learning network for classification. The mappers in the MRF carry out the feature selection process with the proposed Adaptive E-Bat algorithm, which is a combination of adaptive, Exponential Weighted Moving Average (EWMA) and the Bat algorithm (BA) concepts. Using the features, the reducers perform the classification using Deep Belief Network (DBN) that is trained with the proposed Adaptive E-Bat algorithm. The performance of the proposed Adaptive E-Bat DBN method is evaluated in terms of metrics, namely accuracy and True Positive rate (TPR); a higher accuracy of 0.8998 and higher TPR of 0.9144 are obtained, that show the superiority of the proposed Adaptive E-Bat DBN method in effective big data classification.

11 illus, 2 tables, 37 ref

000700   ACHARYYA R (Civil Engineering Dep, Indian Institute of Technology, Powai- 400 076, Email: rana.acharyya@dituniversity.edu.in) : Assessment of overall response of interacting skirted strip footings located on layered soil. Sadhana 2021, 46, 16.

In the present research, the overall response of interacting skirted strip footings resting on soft clayey soil over dense sand has been numerically investigated with the aid of finite element. The load carrying capacity of interfering skirted strip footings has been assessed by altering different geometrical and geotechnical parameters namely, depth of clayey layer, depth of water table, embedment depth of footing and spacing between footings. The interacting mechanism of skirted strip footings has been perceived through displacement mechanism. Moreover, the bending moment patterns of interfering skirts have been investigated for various spacings. Finally, the critical spacing, the spacing after which the interfering skirted strip footing behaves as isolated skirted strip footing, has been assessed through changing various geometrical and geotechnical parameters. It has been observed that changing of water table depth has no impact over critical spacing of skirted strip footings. It has been perceived that the extreme bending moment in interfering skirt increases with increasing the spacing between skirted strip footings up to critical spacing and beyond critical spacing the obtained maximum bending moments are identical.

20 illus, 3 tables, 35 ref

000699   BHAT M N, MUSHTAQ S, MOHBE M (Metallurgical and Materials Engineering Dep, National Institute of Technology, Srinagar- 190 006, Email: nadeem.nit.06@gmail.com) : Impact of section thickness on cooling curve morphology, structure and properties of spheroidal graphite cast iron. Sadhana 2021, 46, 17.

In the current scenario, the energy crisis is on the continuous rise; researchers and academicians are actively working towards a common goal of energy savings by different means. Spheroidal graphite cast iron (SGI) is one of the major alloys used for automobile and structural applications. Manufacturing industries are more focused on using lightweight components to minimize the overall energy requirements. Nevertheless, the complexity of producing thin-walled SGI products is a challenge. In this study, the solidification cooling curve morphology and microstructure of SGI with varying section/wall thickness are investigated. The results obtained from the simulation of stepbar castings of varying section thickness show that thick sections have longer eutectic reaction thermal arrest due to release of latent heat by the formation of graphite. It is also observed that thin sections have a higher degree of undercooling. Microstructural investigation shows that thin sections have higher hardness and strength due to higher pearlite fraction, but the amount of graphite formed in thin sections is reduced, which could lead to aggravated carbide formation in SGI. Thus it is evident that to avoid the formation of carbides in thin-walled SGI castings more inoculation degree is required to promote graphite formation, which will ultimately suppress carbides precipitation. The results obtained from the cooling curve analysis are in agreement with the actual properties of SGI casting.

13 illus, 1 table, 18 ref

000698   BHAT M N, MUSHTAQ S, MOHBE M (Metallurgical and Materials Engineering Dep, National Institute of Technology, Srinagar- 190 006, Email: nadeem.nit.06@gmail.com) : Impact of section thickness on cooling curve morphology, structure and properties of spheroidal graphite cast iron. Sadhana 2021, 46, 17.

In the current scenario, the energy crisis is on the continuous rise; researchers and academicians are actively working towards a common goal of energy savings by different means. Spheroidal graphite cast iron (SGI) is one of the major alloys used for automobile and structural applications. Manufacturing industries are more focused on using lightweight components to minimize the overall energy requirements. Nevertheless, the complexity of producing thin-walled SGI products is a challenge. In this study, the solidification cooling curve morphology and microstructure of SGI with varying section/wall thickness are investigated. The results obtained from the simulation of stepbar castings of varying section thickness show that thick sections have longer eutectic reaction thermal arrest due to release of latent heat by the formation of graphite. It is also observed that thin sections have a higher degree of undercooling. Microstructural investigation shows that thin sections have higher hardness and strength due to higher pearlite fraction, but the amount of graphite formed in thin sections is reduced, which could lead to aggravated carbide formation in SGI. Thus it is evident that to avoid the formation of carbides in thin-walled SGI castings more inoculation degree is required to promote graphite formation, which will ultimately suppress carbides precipitation. The results obtained from the cooling curve analysis are in agreement with the actual properties of SGI casting.

13 illus, 1 table, 18 ref

000696   DUTTA P, BHATTACHARYA P (Civil Engineering Dep, Indian Institute of Technology, West Bengal- 721 302, Email: pujadutta@iitkgp.ac.in) : Determination of support pressure for semi-elliptical tunnels in anisotropic and nonhomogeneous soil by lower bound limit analysis. Sadhana 2021, 46, 19.

This research work examines the stability of long semi-elliptical tunnels in purely cohesive and cohesionless soils. The support pressure ($\sigma$i) required to apply along the tunnel periphery by means of lining and anchorage system has been evaluated using lower bound limit analysis with finite elements and second-order conic programming technique (SOCP). The results are presented in terms of normalized support pressure as (i) $\sigma$i/c_v0 in purely cohesive soil for different combinations of $\gamma$D/c_v0 and ac and (ii) $\sigma$i/cD in cohesionless soil for different combinations of /v and a/ considering different values of 2h/D and H/D of tunnel where h, D and H are height of tunnel, width of tunnel and soil cover depth of the semi-elliptical tunnel, respectively; c_v0, /v and c are soil undrained shear strength of cohesive soil in vertical direction at the ground level, peak vertical friction angle of cohesionless soil and unit weight of all type of soils, respectively; ac and a/ are anisotropy factors in cohesive and cohesionless soil, respectively. The value of ri/c_v0 has been observed to increase with an increase in cD/cv0 and ac. The value of ri/cD increases with a decrease in /v and increase in a/. The increase in aspect ratio of tunnel profile (2h/D) causes an increase in normalized support pressure in both purely cohesive and cohesionless soils. The effects of increase of undrained shear strength in isotropic purely cohesive soil on the stability of tunnel have also been studied. The support pressure is observed to decrease with increase in nonhomogeneity of cohesive soil. The combined effect of soil anisotropy and linearly increasing undrained shear strength may reduce the required magnitude of ri/cv0 in comparison with the value of ri/cv0 in isotropic homogeneous cohesive soil, especially for H/D > l

6 illus, 2 tables, 23 ref

000695   GUNJI B M, PABBA S K, RAJARAM I R, SORAKAYALA P S, DUBEY A , DEEPAK B B V L, BISWAL B B, BAHUBALENDRUNI M V A R (Mechanical Engineering Dep, Vellore Institute of Technology, Vellore- 632 014, Email: bmgunji@gmail.com) : Optimal disassembly sequence generation and disposal of parts using stability graph cut-set method for end of life product. Sadhana 2021, 46, 21.

Disassembly is one of the essential operations in manufacturing to recover the useful parts of the product after End of Life (EOL). Moreover, by generating an optimal disassembly sequence, the time to dismantle the product will be reduced, and in turn, cost also reduces. However, achieving an optimal disassembly sequence is not an easy task as it is an NP-hard combinatorial problem. Many researchers followed different approaches like mathematical, knowledge-based and artificial intelligence (AI)-based methods to generate optimal disassembly sequences. Most of the researchers concentrate on generating the optimal disassembly sequence, but only a few of them discuss the disposal of the parts after EOL. It is very much essential to consider the type of disposal that has to follow the individual components after dismantle to reduce the effect on the environment due to parts of the EOL product. In this research work, a stability graph cut-set method is applied to generate optimal disassembly sequences by considering the minimum number of directional changes as a fitness equation. In the proposed methodology, a stability graph is formulated for the considered assembly to apply cut-set rules for generating optimal assembly sequences. Later, the reverse of the obtained optimal assembly sequences is followed to generate the optimal disassembly sequences. In this strategy, along with the generation of optimal disassembly sequences, the type of disposal (like landfill, incineration and recycling) that has to follow for the individual parts is also discussed using a SOLIDWORKS sustainable tool. The proposed stability graph cut-set method is validated using an eleven-part punching machine assembly to generate the optimal disassembly sequences; also the type of disposal that has to follow for each part after dismantle is discussed. Moreover, the proposed methodology is compared to the well-known algorithms [genetic algorithm (GA) and ant colony optimization (ACO) algorithm] in terms of the number of iterations, the number of optimal disassembly sequences generated and fitness value to check the performance of the algorithm.

27 illus, 27 tables, 32 ref

000694   DIVYANAVAMANI J, LAVANYA A, SATHIK M J, VIJAYAKUMAR K (Electrical and Electronics Engineering Dep, SRM Institute of Science and Technology, Kattankulathur, Tamil Nadu, Email: divyateddy1@gmail.com) : Expandable transformer-less high-gain dc–dc converter based on quasi-Z source and multiplier cells. Sadhana 2021, 46, 22.

In this paper, a novel high-gain transformer-less dc–dc converter is presented. This topology is acquired by integrating two high-gain cells like quasi-Z source (QZ) and gain multiplier (GM) cells with a quadratic boost converter. The boosting factor of the proposed topology is increased both in the numerator and denominator of the voltage conversion ratio, which furnishes flexibility in designing the converter. The cost of the converter is low due to lesser voltage stress across the devices. Operating principle and steady-state analysis of the converter are analyzed in continuous conduction and discontinuous conduction modes. Considering the boundary conduction mode and voltage ripple, the design expression of the passive components is derived. A suitable duty cycle for realizing higher voltage gain is determined. The performance of the converter is analyzed and compared to those of similar QZ-based converters. To validate the theoretical study, a 50 W prototype is implemented and tested.

5 illus, 4 tables, 14 ref

000693   CHOUDHARY B S, AGRAWAL A, ARORA R (Mining Engineering Dep, Indian Institute of Technology, Dhanbad- 826 004, Email: bhanwar_ism@hotmail.com) : Stemming material and Inter-row delay timing effect on blast results in limestone mines. Sadhana 2021, 46, 23.

Safe and efficient blasting is the prime objective of any blasting engineer. The safe and efficient is generally called when there are no fly rocks, less ground vibration and optimum fragmentation with loose muckpile. This study describes the use of stemming material and inter-row delay timing effect to improve the efficiency of the blast and its results. From the study, it was found that the use of aggregates or screened drill cuttings having a size of 3-7 mm helps in reducing the collar generated boulders as well as increasing the looseness of the muckpile. Change in delay timing between rows also determined that the mean fragment sizes are fair and uniform, muckpile parameters were improved when the delay between first and second row was 8-14 ms/m of burden and the delay gap between last two rows was 5 ms/m of the burden.

14 illus, 2 tables, 41 ref

000691   CHOLAKE S, SUNDARARAJAN T, VENKATESHAN S P (Mechanical Engineering Dep, Indian Institute of Technology, Madras, Chennai, Email: tsundar@iitm.ac) : Onset of natural convection in a differentially heated layer of gray and non-gray gas mixtures. Sadhana 2021, 46, 25.

The onset of convection instability in a differentially heated layer consisting of gray and non-gray gaseous mixtures is studied numerically. The conditions investigated cover a wide range of Planck number values (Pl ¼ jkT 4rT3 0 ), from the conduction-dominated regime of Pl 1 to the radiation-dominated regime of Pl 1. The linear stability theory is applied to mass, momentum and energy balance equations and the resulting linear stability equations are solved by Chebyshev spectral collocation method. The divergence of radiative flux is solved by the finite-volume-based discrete ordinates method. The Spectral Line Weighted sum of gray gas (SLW) model is used to represent the fine spectral variation of absorption coefficient for a non-gray gas medium. The results indicate that the critical Rayleigh number (Rac) for the onset of convection increases with mean temperature (T0) in the conduction-dominated regime at low values of T0. In the radiation-dominated regime (Pl 1), Rac decreases with T0 for gray media. If the medium is non-gray, the critical Rac reduces to even lower values (as compared with those of gray gases) due to the dependence of gas absorptivity on temperature T0. A reduction in the wall emissivity value increases the stability of the fluid layer due to reflection of radiation from the wall, in the radiation-dominated regime. The reverse trend is seen for Pl 1. The critical parameters also significantly depend on the concentrations of radiatively participating gases in the mixture. The temperature profile in the fluid layer transforms from a linear profile in conduction regime to a stratified profile with steep gradients near the walls, in the presence of non-gray participating gases.

14 illus, 9 tables, 26 ref

000690   SAM C A, JEGATHESAN V (Electrical and Electronics Engineering Dep, Karunya Institute of Technology and Sciences, Coimbatore, Tamil Nadu, Email: carolineannsam@gmail.com) : Bidirectional integrated on-board chargers for electric vehicles—a review. Sadhana 2021, 46, 26.

This paper reviews about the bidirectional on-board chargers for electric vehicles. The chargers are of two types: on-board chargers and off-board chargers. The overall size, weight and cost of the onboard chargers can be reduced using integrated on-board chargers where the drive train components are used for propulsion as well as for charging. Four-quadrant operation of the drive is possible using the bidirectional converters in the drive train. Regenerative braking control in the integrated on-board chargers aids in proper utilization of braking energy, which in turn increases the driving range of the vehicle. Various on-board chargers are presented and their working, advantages and limitations are discussed here.

10 illus, 2 tables, 93 ref

000689   NAGARAJ R K, D’SOUZA M (Electronics and Communication Engineering Dep, B M S Coll of Engineering, Bangalore- 560 019, Email: rajanikanthnkashi.ece@bmsce.ac.in) : A verifiable multi-agent framework for dependable and adaptable avionics. Sadhana 2021, 46, 27.

The aerospace industry is continuously looking for improvements in operational efficiency and performance of systems. In its quest to do so, the industry is turning to Intelligent Adaptive Systems as a possible solution in many areas. However, the nature of the domain imposes expectations of safety, correctness and guarantees of behaviour from such systems. Meeting these expectations simultaneously, finally leading to certified products, poses many challenging problems. A research gap is perceived when the cycle of requirements, system design, verification and validation is examined, paving the need for correctness and guarantees of specifications in the early stages of a complex adaptive avionics system. We present a framework that is targeted for a broad class of avionics systems, engineered for short- and long-term system behaviours, resilient, real-time decision making, establishing trust on the way to certification and being amenable to analysis using formal methods. We have used this framework with two case studies (Flight Management System and Unmanned Aircraft System) and provide an application of this framework with one case study.

6 illus, 4 tables, 61 ref

000686   WANG S, ZHANG L, YIN G, CHEN J, WANG L (Hohai Univ, Nanjing 210098, People’s Republic of China, Email: qqwang@hhu.edu.cn) : Vibration analysis of the steel shell flow tube in a vertical axial pumping station based on fluid-structure interaction (FSI) method. Sadhana 2021, 46, 30.

Design scheme of steel shell flow tube in the inflow and outflow passage of the vertical axial pumping stations takes advantages of conventional concrete scheme in simple construction and convenient installation of the pump. A three-dimensional pumping station model was established based on fluid-structure interaction method in ADINA. Typical measure points were selected to analyze the features of the unsteady turbulent flow in fluid zone and vibration responses of the steel shell tube in solid zone. Time and frequency domain investigation of fluid domain revealed the transmission path of pressure pulsation, that was the pulsation transferred from the pump to the inlet and outlet respectively with amplitudes sharply decreasing, which verified the rationality of calculation and established the basis on structure analysis. Dynamic displacement, velocity and acceleration analysis of measure points in steel shell tube showed that top shell domain near the inlet of steel shell flow tube had obvious vibration amplitude, which required great attention. The first main frequency equaled the rotational frequency of the blade, indicating one of the most important vibration sources in the pump was the pressure pulsation induced by blade rotation. The design scheme of steel shell flow tube is practical and could be promoted to other similar pumping stations because the vibration amplitude is much lower than the regularity. This research provides great importance to the design and application of the steel shell flow tube in pumping stations

14 illus, 5 tables, 28 ref

000685   KRISHNA D A, PRIYADARSINI R S, NARAYANAN S (Civil Engineering Dep, Engineering Coll, Thiruvananthapuram, Kerala, Email: anupamakrishnad@gmail.com) : High temperature effects on different grades of concrete. Sadhana 2021, 46, 31.

Concrete structures are liable to be exposed to fire during their lifetime. After exposure to high temperature, the strength of concrete is determined only by its residual properties. The method of cooling, after exposure, is one of the significant factors in determining the residual properties of concrete. The compressive strength, tensile strength, stress-strain response and elastic modulus of concrete are the important properties to be considered in the design of fire resistant structures. In this paper, the behaviour of high temperature exposure of three different grades of concrete M20, M45 and M60 are considered. The specimens were subjected to high temperature regime of 100 ^oC–900 ^oC and were cooled by different methods. The maximum degradation of mechanical properties was observed between temperature regimes of 400 ^oC to 600 ^oC. High strength concrete was found to be more vulnerable compared to normal strength concrete. Mathematical models expressing the variation of different mechanical properties of concrete were developed and explained.

2 illus, 3 tables, 35 ref

000684   SINGH P K, MODANWAL R P, KUMAR D (Mechanical Engineering Dep, Sant Longowal Institute of Engineering and Technology, Longowal- 148 106, Email: pkschauhan@gmail.com) : Fabrication and mechanical characterization of glass fiber/Al₂O₃ hybrid-epoxy composite. Sadhana 2021, 46, 32.

This paper presents the development and mechanical characterization of hybrid composite consisting of glass fiber and aluminum oxide (Al₂O₃) particles reinforced with epoxy matrix. The hybrid Glass Fiber Reinforced Polymer (GFRP) composite has been fabricated using different weight fractions (20 %, 30 %, and 40 %) and different particles size (20 lm, 40 lm and 60 lm) of Al₂O₃ along with chopped E-glass fiber reinforced with epoxy resin matrix, following the hand lay-up method. Further, the mechanical characterization has been carried out through tensile test, impact test, and bending test. The effect of process parameters on mechanical properties of the composite has been studied using response surface methodology (RSM) and analysis of variance (ANOVA). It has been found that an increase in weight percentage of Al₂O₃ particles improves the mechanical properties. However, the increase in size of Al₂O₃ particles shows an adverse effect on mechanical properties. The results have been optimized using the desirability function approach, and validated through a confirmation test

6 illus, 7 tables, 15 ref

000682   SINGH P K, GULATI V (Mechanical Engineering Dep, Sant Longowal Institute of Engineering and Technology, Longowal- 148 106, Email: pkschauhan@gmail.com) : Tolerance analysis and yield estimation using Monte Carlo simulation – case study on linear and nonlinear mechanical systems. Sadhana 2021, 46, 34.

Dimensions of individual components give rise to a critical dimension in an assembly, called the assembly dimension(s) or the assembly response(s). This concept is applicable to any engineering system. Thus, a variation in the individual dimension/characteristics directly affects the assembly response or the performance of the system. The random assembly of the individual dimensions gives rise to a statistical distribution of assembly response. Tolerance analysis is the estimation of resultant variation of the assembly response, for a given set of tolerances associated with individual dimensions, and the functional relationship between the individual dimensions and the assembly response. Several methods for tolerance analysis have been reported over the decades. The Monte Carlo simulation still remains the benchmark approach for testing of the precision obtained by any other method. This paper presents two case studies to explore the insight of the methodology for tolerance analysis. The first case study is on a linear assembly while the second one is the nonlinear assembly. Three sub-studies considering (a) uniform distribution, (b) normal distribution, and (c) beta distribution, of individual dimensions have been attempted in each of the two cases. Further, in each sub-study, the tolerance analysis and the yield estimation has been carried out for the worst-case criteria, followed by analysis of the estimated yield due to reduction of assembly tolerance. The results have been presented in the form of histograms for all 2 9 3 9 3 cases.

12 illus, 10 tables, 36 ref

000681   PATIL C V, SUMA M S (Electronics and Communication Engineering Dep, Visvesvaraya Technological Univ, Bangalore- 560 019, Email: cpatil365@gmail.com) : Compact modeling of through silicon vias for thermal analysis in 3-D IC structures. Sadhana 2021, 46, 35.

Heat mitigation is a major challenge in 3-D IC (Three-Dimensional Integrated Circuit) realization. A study of analytical thermal behavior of the TSV (Through Silicon Via) is very important. Simple and compact yet other models were found deficient to solve this problem in the literature survey. In this paper, resistance networks are used to model the heat transfer of the TSVs in both vertical and horizontal directions in simpler and compact models. The accuracy of such models is compared to those from the commercially available CFD (computational fluid dynamics) tool. The errors of corrections between the tool and developed models are corrected by multiplication factors, resulting in 4.18 % accuracy. Varying the thicknesses of a liner, filler, soldering, and substrate materials is studied concerning heat transfer and physical behavior of three planar TSV stacked systems. The major purpose is to incorporate both vertical and horizontal thermal resistance networks captured more accurately in heat dissipation paths. Proposed models of TSVs can be used in the active interposer simulations or the face-to-face fabrication stacked methods of the 3-D IC structures.

8 illus, 1 table, 27 ref

000680   SOFUOGLU M A (Mechanical Engineering Dep, Eskisehir Osmangazi Univ, Eskisehir, Turkey, Email: asofuoglu@ogu.edu.tr) : A new biomaterial selection approach using reference ideal method. Sadhana 2021, 46, 36.

Biomaterials are natural/synthetic materials used to perform the functions of living tissues in the body. Biomaterials are in contact with fluids continuously or for a certain period. The body’s reactions to these materials are extremely different. For this reason, the correct selection of biomaterials is essential. In this research, a novel multi-criteria decision-making procedure (Reference Ideal Method) has been used for orthopedists/practitioners, prosthesis and implant manufacturers. This method produces successful results, especially in target-based problems. The method has not been used for the selection of target-based biomaterials before. In this study, it was applied to two different biomaterial selection problems from the literature. Consistent results have been produced with studies in the literature.

1 illus, 6 tables, 26 ref

000679   HIREMATH C R, RAVIKIRAN K (Mechanical Engineering Dep, BLDEA’s V. P. Dr. P. G. Halakatti Coll of Engineering and Technology, Vijayapur- 586 103, Email: chandra.hiremath@yahoo.com;) : Experimental analysis of low-temperature grain drying performance of vertical packed clay and clay-additives composite desiccant beds. Sadhana 2021, 46, 37.

A laboratory model of a forced circulation desiccant based green pea drying system operating in an open-loop is constructed and tested. The green pea drying process is divided into two stages involving dehumidification by the desiccant bed and green peas drying by dehumidified process air. Removal of moisture from the process air has been achieved by vertical packed composite desiccant beds. The composite desiccant used are heat treated clay with CaCl₂ being impregnated and clay with additives like horse dung and sawdust, again being heated, treated and later impregnated with CaCl₂. The green peas were dried for a process time of one hour. The drying was quite sharp during the initial process time of 500 s and from then onwards proceeded at a constant rate. For the identical bed masses, The performance of heat treated clay-additives based beds in moisture reduction and enhancement in enthalpy of process air is higher. The experimental study reveals the average heat content of air entering the dryer is 1.46, 2.46 and 2.38 kJ for heat-treated clay-CaCl₂, clay-horse dung-CaCl₂ and clay-sawdust-CaCl₂ composite desiccant beds of 700 g mass.

13 illus, 3 tables, 26 ref

000676   GUPTA N, RAMKUMAR P L (Mechanical Engineering Dep, Institute of Infrastructure Technology Research and Management, Ahmedabad, Gujarat, Email: nikitagupta10192@gmail.com) : Effect of coir content on mechanical and thermal properties of LLDPE/coir blend processed by rotational molding. Sadhana 2021, 46, 40.

Rotational Molding is a unique polymer processing technique that gives an advantage of having stress free end product. Majorly, Linear Low Density Polyethylene (LLDPE) is preferred as a base resin for rotomolding. However, incorporation of additives becomes necessary to improve mechanical properties and viscoelasticity as incumbent for few applications. The present research makes an attempt to investigate the effect of coir fiber on rotationally moldable LLDPE. Based on preliminary processing experiments, 10 % or less Coir in its powder form when mixed with LLDPE was found to account a better flow ability as a prerequisite for roto moldability. Hence, the effect of 3 %, 5 %, 7 % and 10 % Coir mixed with LLDPE was experimented for the roto molded product to determine the mechanical properties, viz. tensile, flexural, hardness and impact strength. Also, the rate of heat transfer was evaluated subjected to the data recorded for mold, oven and internal air temperature when processing LLDPE/Coir considering different weight percentages. Crystallinity of the blend was examined based on DSC analysis for the distinguished percentage of coir incorporated in LLDPE. The experimental results depicted an improvised mechanical properties by 7 % or less fiber addition, and beyond that, the properties were found to be regressed. The present work successfully engulfed Coir with LLDPE, producing a uniform distribution along the sides of the mold without applying any external pressure. Therefore, fiber integration in the rotomolding process is believed to be possible thus preserving homogeneous randomly distributed fiber dispersion.

15 illus, 4 tables, 54 ref

000675   SHOUGRAKPAM S, TRIVEDI A (Civil Engineering Dep, Delhi Technological Univ, New Delhi- 110 042, Email: sangee1mit@rediffmail.com) : Harnessing microbially induced calcite precipitates to use in improving the engineering properties of loose sandy soils. Sadhana 2021, 46, 41.

This study investigates harnessing of microbially induced calcite precipitation (MICP) to use in soil treatment to improve the engineering properties of loose sandy soils. Experiments were conducted in sand specimens using a channel, a pond, and four sand-columns. A bacterial treatment followed by a cementation reagent solution (CRS) was applied to trigger calcite (CaCO₃) precipitates. The submerged and surface percolation treatment methods were carried out in sand using CRS as the treatment solution. The treatment solution was maintained in an alkaline range (pH$\ge$7). The alkaline condition ensures active microbial induced calcite precipitation in the sand. The calcite precipitates bind the sand particles to increase the strength and stiffness of the soil matrix. The calcite bridged the sand particles and formed a biocemented water-impermeable crust layer ( 2 mm thick). The calcite act as pore-filling material through the bioclogging process to reduce porosity and permeability. Permeability tests evaluate the effect of seepage control. The permeability was reduced to three order-of-magnitude ( 99 %) on the 7th day with little variation (100 %) until the 14th day. The compressive strength of the biotreated columns was between 585 and 875 kPa. The calcite content in the upper 10 mm thick in different columns was in the range of 11–14 % and was gradually reduced from 9.8 to 3.4 % below 10 mm. Hence, the observed 5–15 % calcite content in natural biocemented products is comparable to MICP treated specimens. The scanning electron microscopic images show the calcite distribution patterns in the sand matrix.

11 illus, 4 tables, 34 ref

000673   KIRAZ A, ACIKGOZ N (Industrial Engineering Dep, Sakarya Univ, Sakarya, Turkey, Email: kiraz@sakarya.edu.tr) : A fuzzy-logic-based approach to the EFQM model for performance enhancement. Sadhana 2021, 46, 43.

Institutions could be longstanding if they are consistent with well-defined strategies. Self-assessment activities are among the significant ways to identify the level of reaching strategic objectives of institutions. In recent studies, different TQM models were presented to evaluate organizational performance. The European Foundation for Quality Management (EFQM) excellence model is a commonly used model for selfassessment. In this study, Fuzzy EFQM (FEFQM) model is proposed in order to minimize the calculation deviation of expert opinions and to measure the level of institutionalization more consistently. ’If- then’ the rules were produced by utilizing the CN2 induction algorithm in accordance with the current rule base, due to the implementation of Matlab fuzzy logic toolbox takes long time and it has some reliability issues. Two various Fuzzy EFQM models have been established on the basis of the CN2 algorithm with various aggregation methods such as max and sum, in other words, FEFQM_CN2/max and FEFQM_CN2/sum. The models were applied to 10 institutions and comparisons were made with classical EFQM and FEFQM models. As a result, the FEFQM_CN2/sum model and the classical EFQM excellence model score were found by the Mean Absolute Percentage Error as 2.33 %. In accordance with the experimental findings, it is thought the model can be used as a guide for EFQM assessors and policy makers.

6 illus, 7 tables, 51 ref

000669   CHANDLA N K, KANT S, GOUD M M (Production and Industrial Engineering Dep, Punjab Engineering Coll, Chandigarh- 160 012, Email: nagender.mechengg@gmail.com) : Mechanical, tribological and microstructural characterization of stir cast Al-6061 metal/matrix composites—a comprehensive review. Sadhana 2021, 46, 47.

Aluminum 6061 is a heat-treated, extruded alloy used for various engineering and structural components such as wings and fuselage of aircraft, railings, window frames, driveshaft and valves, etc. Al-6061 is widely used amongst its 6000 aluminum series because of its outstanding properties like medium to high strength, excellent environmental resistance, low density, high elongation at break and superior machinability. This paper aims to review the mechanical, tribological and microstructural characterization of stir cast Al-6061 metal/matrix composites (MMCs). In this review article an attempt has been made to demonstrate the effect of different reinforcements on metallurgical behavior of Al-6061 MMC. The particulates reinforcements like SiC, Al2O3, Gr, B4C, TiC, fly ash, bagasse ash and red mud were dispersed with Al-6061 alloy through stir casting route as single, dual and triple reinforcements. The experimental results showed significant improvement in tribological and mechanical properties of Al-6061 MMC as compared with Al-6061 alloy. The overall characterizations of Al-6061 MMC are summarized with key findings, which will provide a methodical approach for researchers in selecting optimized parameters for the fabrication of aluminum-based MMC.

25 illus, 9 tables, 117 ref