001393   RANI K V, JAWHAR S J (Information and Communication Engineering Dep, Anna Univ, Chennai) : Novel method for lung tumour detection using wavelet shrinkage-based double classifier analysis. IETE J Res 2021, 67(4), 514-31.

Medical image detection and classification play an important role in medical research. Tumour detection is a process of crucial importance in oncology. The aim of this paper is to devise an approach for efficient image enhancement, tumour detection, and classification on computed tomographic lung images. Three different application-related methods on computed tomography (CT) images have been designed and implemented in this work. The first method, which was based on image quality, enhances the performance of the medical images. Generally, the CT images are very sensitive to noise and are difficult to handle. Proper care may be taken by introducing some preprocessing algorithms like enhancement algorithms and filters. According to this, an image enhancement algorithm, Wavelet Shrinkage adaptive histogram Equalization (WSAHE), with anisotropic diffusion filter (ADF) was introduced to improve the contrast of the CT images and denoising. In the second method Seed Region growing with Random walk segmentation algorithm (SRGWRWS) is proposed for lung tumour segmentation. In the third method GLCM features, FOS features, structural features, and combinational features are calculated from the segmented lung images. After segmentation, the tumour classification is done by Multi-class support vector machine (MCSVM) and Descend RUSBOOST classifiers. Here, MCSVM classifier was used to find whether the input CT tumour image is suspicious, benign or malignant. Overall accuracy of 92% is obtained using Descend RUSBOOST classifier with GLCM features, FOS features, structural features, combinational features and overall accuracy of 97% is obtained using MCSVM classifier with GLCM feature in MATLAB 2017a software.

10 illus, 5 tables, 41 ref

001392   ABBASZADEH J, MOSTAFAPOUR M (Electrical Engineering Dep, Islamic Azad Univ, Urmia, Iran) : Determination of proper ultrasonic frequency based on wall thickness of the metal pipes in ultrasonic tomography systems. IETE J Res 2021, 67(4), 499-513.

In this research, determination of the applicable ultrasonic sensors based on the wall thickness of the metal pipe for the purpose of transmission tomography is studied. The range of applicable ultrasonic frequencies according to the thickness of the metal pipe is investigated. For the study of the behaviour of ultrasonic wave propagation in various metal pipes of different thicknesses, twodimensional (2D) modelling of the system with COMSOL software is utilized. The paper presents an exploration of the effect of variation of the wall thickness on the propagation of ultrasonic waves, including a frequency analysis in order to find the maximum applicable frequency. The simulation results are compared to experimental data and are shown to provide key insight for this well-defined experimental case by explaining the signals obtainedfrom the experimental setup. Finally, the experimental results which are useful for further investigation for the application of ultrasonic transmission tomography in the industry are illustrated.

16 illus, 1 table, 27 ref

001390   VINODHA E, RAGHAVAN S (Electronics and Communication Engineering Dep, National Institute of Technology, Tiruchirappalli- 620 015) : A low-profile wide band “s” shaped rectangular dielectric resonator antenna for “x” band application. IETE J Res 2021, 67(4), 485-90.

The main goal of this article is to design a low-profile wide band Rectangular Dielectric Resonator Antenna (RDRA). The proposed “S” shaped rectangular DRA is excited by means of a popular microstrip line feeding. By using “S” shaped design, our proposed DRA yields an impedance bandwidth of 32% from 9.2 to 12.48 GHz, covering “X” band frequency. The proposed antenna has a wide impedance bandwidth, extremely low profile with the volume of 447 mm3, and a thickness equal to 2.5 mm. This design provides stable radiation patterns and high radiation efficiency. The proposed design is compared with some other designs in the literature in order to emphasize its significance. The proposed RDRA was fabricated and its characteristics were tested. Excellent agreement between simulated and measured ones was obtained.

10 illus, 2 tables, 22 ref

001389   ASADPOR L, REZVANI M H (Electrical Engineering Dep, Islamic Azad Univ, Urmia, Iran) : Compact UWB CPW-fed monopole antenna with variable triple-band-notched property. IETE J Res 2021, 67(4), 476-84.

In this paper, a modified compact ultra-wide band (UWB) monopole antenna possessing U-shaped slots and multi-band rejection characteristics are presented. The dimensions of the presented antenna are 30 × 30 × 1 mm³, and it is fed by the coplanar waveguide (CPW). Inverted U-shaped slots produce three notched frequency bands at 2.5, 3.5 and 5.5 GHz. The lengths of the slots are modified for adjusting the frequency bands. The results of measurement and simulation show a VSWR of ≤ 2 for the antenna. The presented antenna is a perfect candidate for applications in UWB because of its omnidirectional radiation patterns. The antenna shows a radiation efficiency of above 85%.

12 illus, 27 ref

001388   VANI V, PRASHANTH K V M (Electronics & Communication Engineering Dep, ISJB Institute of Technology, Bengaluru) : Image enhancement of wireless capsule endoscopy frames using image fusion technique. IETE J Res 2021, 67(4), 463-75.

Volume restriction, low battery capacity and low focal length camera in Wireless Capsule Endoscopy (WCE) result in images being of lower contrast, darkness, un-even brightness and image degradations. In this paper, a Laplacian pyramid based Image fusion of Contrast Limited Adaptive Histogram Equalization (CLAHE) and Multi-Scale Retinex with Colour Restoration (MSRCR) to integrate information of both techniques have been proposed. The proposed technique combines the information from CLAHE and MSRCR, reduces uncertainties, redundancy and maximizes the information. Experimental evaluation reveals that the proposed method outperforms existing methods in terms of Peak Signal to Noise Ratio and Structural Similarity Index Measure.

12 illus, 1 table, 42 ref

001387   ABIOGHLI M, KESHTKAR A, NASER-MOGHADASI M, GHALA B (Electrical and Computer Engineering Dep, Islamic Azad Univ, Tehran, Iran) : A frequency reconfigurable band-notched uwb dielectric resonator antenna with a wide-tuning range for cognitive radio systems. IETE J Res 2021, 67(4), 453-62.

A new reconfigurable band-notched ultra-wideband (UWB) dielectric resonator antenna (DRA) has been designed and fabricated for cognitive radio (CR) applications. The UWB antenna design comprises a dielectric resonator as a radiation element, a ground plane, and a microstrip feed line. The frequency band’s rejection mechanism is achieved by cutting two slots and adding an L-shaped stub on the ground plane. The reconfigurable function is created by PIN diode switches to change the current distribution path on the ground plane. A preliminary model of the DRA was fabricated, and its efficiency was verified. The proposed antenna occupies an area of 40 × 40 × 7.3 mm. The simulated and measured results have demonstrated suitable radiation patterns attained by the proposed antenna, which operates within the UWBfrequency range of 3–11 GHz. Moreover, the antenna has shown an ability by rejecting switchable bands to achieve the WiMAX (3.2–3.65 GHz), WLAN 5 GHz (4.8–6 GHz), and ITU 8 GHz (8–8.3 GHz). Also, this antenna can be operated as dual and triple band-notched antennas.

14 illus, 2 tables, 25 ref

001315   Sandeep Kumar D S, Chethan K, Chethan Kumar B (Civil Engineering Dep, Engineering Coll, Mandya- 571 401, Karnataka) : Effect of alkali solution dosage on sugarcane bagasse ash based sustainable alkali activated slag concrete. Eco Env Cons 2021, 27(2), 888-93.

Production of ordinary Portland cement (OPC) contributes around 7% of global carbon dioxide (CO2 ) to environment. In order to reduce the environmental impact caused by OPC production sustainable material development is essential and also sustainable material development plays a vital role in present day construction practice too. Alkali activated slag (AAS) binders is one such sustainable material. Present study investigates the effect of Na₂ O dosage (4-5.5% of total binder content), modules of silica (Ms: 0.75- 1.75) and bagasse ash (BA) replacement (0, 25, and 50%) to ground granulated blast furnace slag (GGBS) were studied on AAS concrete (AASC) mixture preparation. Mixtures which provide maximum compressive strength were considered as optimal mixture. BA replacement in AASC mixture results in decrease in compressive strength. Further, maximum compressive strength is observed in mixture prepared with alkaline solution of concentration of 5% Na₂ O dosage, and MS of 1.

4 illus, 2 tables, 12 ref

001313   TEJAS K, RADHIKA K N, MUKHERJEE B (Civil Engineering Dep, Acharya Institute of Technology, Bengaluru, Karnataka) : Impact of decadal change in basin morphometry due to urbanization – Bengaluru, India. Eco Env Cons 2021, 27(2), 876-82.

Bangalore is one of the fastest growing cities of Asia, is having population of over ten million, the thirdmost populous city and fifth-most populous urban agglomeration in India. The city was not as big it is now with advent of growing software industry the overall dimensions of city changed in less than two decades. Since the inception of the city, Bengaluru had a proper set of drainage characteristics through a proper network of tanks, surface water bodies interconnected. But unplanned and unpredicted urbanization has led to forceful change of course of streams, encroachment of tanks etc.… which has affected the natural flow of water. This advent of urbanization, various basin morphometric changes it has been experienced in the city and would be a near concerns in future.

10 illus, 4 tables, 9 ref

001304   KUMARI S, SINGHAL D, WALIA R, MUNDAY A (Civil Engineering Dep, Deenbandhu Chhotu Ram Univ of Science & Technology, Sonipat, Haryana) : Utilization of maize cob and rice husk ash in manufacturing paver block concrete for low traffic areas. Eco Env Cons 2021, 27(2), 806-15.

This paper highlights the results of a study which was conducted on M35 grade cast concrete paver blocks using rice husk ash (RHA) and maize cob ash (MCA) partial replaced with Ordinary Portland Cement (OPC). The replacement for rice husk ash was fixed at optimum 10% ash and maize cob ash was varied from 2.5 % to 10%. Control mix concrete was prepared without any replacement and only with ordinary Portland cement. The basic compressive strength was compared for both i.e. with the specimens exposed to sulfuric acid, nitric acid, magnesium sulfate, and sodium sulfate at the ages of 28, 60, and 90 days. The test results confirmed the attainment of requirement of compressive strength with 5% MCA and 10% RHA. While less changes were observed in durable properties of MR concrete than control mix concrete. It was concluded that MR concrete can be used in lawns, open area, parking areas, low traffic areas, houses, and for manufacturing of perforated blocks/grass concrete paving / permeable concrete to be used for vegetation purposes. It can provide good resistance against sulfuric acid produced by the decomposition of organic matter and convert into sulfuric acid after reacting with moisture present in the soil.

5 illus, 9 tables, 13 ref

001281   KARNATAPU L K, ANNAVARAPU S P (Civil Engineering Dep, R.V.R. & J.C. Coll of Engineering, Guntur- 522 019, Andhra Pradesh) : Best compromised reservoir operating policy under uncertain inflows by fuzzy linear programming. Eco Env Cons 2021, 27(2), 650-5.

The operation of the reservoir is a complex phenomenon, in which the operator should take suitable decisions to release water for various users to satisfy their objectives. This is further complicated if uncertainties are involved in the parameters of the reservoir operation process. In order to obtain the compromised optimal solution addressing the uncertainties involved in the parameters of the system, Fuzzy optimization approach is very useful. Compromised solution is obtained by Fuzzy Linear Programming (FLP) model considering inflows are in fuzzy. Firstly, the crisp solution is obtained by linear programming by solving the objective function considering for each set of uncertain inflows and corresponding best and worst values of objective are determined. Then objective function and reservoir inflows are fuzzified by considering linear membership function. Finally best compromised policy is found by maximizing the level of satisfaction () considering the modified fuzzy objective and fuzzy inflows by FLP. The above model is applied to Nagarjuna Sagar reservoir on Krishna River located at border of Andhra Pradesh and Telangana state, India. The objective function considered in the present study is maximization of total irrigation releases subjected to irrigation releases, power releases, storage bounds and continuity constraints. The 75% and 80% dependable inflows are considered in the present study for determining the compromised reservoir operating policy. The maximum level of satisfaction () obtained by simultaneously optimizing the fuzzified objective function and inflows is 0.5 and best compromised monthly operating policy is presented.

6 illus, 2 tables, 9 ref

001247   UDAYAKUMAR J, AJMAL M, AKHIL R, MUHAMMED FAROOQ Z, RAHUL R (Civil Engineering Dep, TKM Coll of Engineering, Kollam- 691 005, Kerala) : Environmental implications of the organic carbon content of soils from different landuses in Kollam District, Kerala. Eco Env Cons 2021, 27-S1, 278-87.

This study focuses on the variations of Soil Organic Carbon (SOC) contents in soils of different land uses like forests, agricultural lands, water bodies, built up areas and industrial areas in Kollam district of Kerala. It is to find the probable environmental implications of the variation in the content of SOC in soils of different land use types of the study area. Soil samples each from the different land uses were collected in polythene bags and the SOC and nitrogen of the soil samples were analysed using CHNS analyser. The soils in the study area are mainly sandy in type. The percentage of gravel is the lowest in the industrial area and the highest in agricultural areas. The sand percentage is minimum for agricultural land and is maximum for industrial areas. The content of fines in the soils of built up areas in the study area is minimum and that in the agricultural land is maximum. The standard deviation of fines is maximum for agricultural lands and minimum for industrial areas.The percentage of fines shows a decrease in trend from forest to built- up / industrial areas. Nitrogen content also follows similar variation. There is no correlation between gravel content and SOC. Sand content in the soil is negatively correlated with the SOC. The percentage of fines shows a positive correlation with SOC. Standard deviation of SOC is similar to standard deviation of percentage of fines. The soils of industrial and built up areas of Kollam district mainly belong to the coastal part of Kollam district. Undisturbed subsurface soils from these areas contain lot of carbonaceous clay and peat. But due to intense land use activities associated with urbanisation, the SOC in the surface layers of the soil might have been removed by soil respiration. This might have locally added CO2 from the soil to the atmosphere. Its local implications on a global phenomenon like climate change is important. It is also interesting to note that SOC closely follows changes in the content of fines in the soil. The land use activities in industrial and built up areas do not permit the formation of fine SOC associated fraction in these soils.

10 illus, 7 tables, 15 ref

001241   RUHELA M, JENA B K, BHARDAWAJ S, BHUTIANI R, AHAMAD F (Environmental Engineering Dep, Swami Vivekanand Subharti Univ, Meerut- 250 005,Uttar Pradesh) : Efficiency of Pistia stratiotes in the treatment of municipal solid waste leachate in an upwards flow constructed wetland system. Eco Env Cons 2021, 27-S1, 25-44.

Constructed wetlands (cw) are one of the effective treatment technologies that have been used to treat various kinds of wastewater and leachate and are very economical and cost-effective, simple and easy to operate, without any complex technology. The BOD5/COD ratio of raw leachate was observed as low (0.27), indicating it as biodegradable leachate. That’s why for the treatment of this leachate, CW’s methods are used. The main objective of the present study is to assess the efficiency of CW’s for the treatment of landfill leachate. To fulfill the objectives of the present study an upwards flow engineered wetland was constructed using gravel, sand and plant (Pistia stratiotes). The efficiency of CW’s was assessed for 21 parameters such as TDS, COD, BOD, NH4 -N, Fluoride, TKN, and Heavy metals, etc. The maximum removal efficiency was observed in the case of BOD (97.58%) followed by COD (97.03%), Turbidity (87.09%) and Sulphate (85.89%) while minimum efficiency was observed in case of pH (8.24%). Due to the large removal efficiency observed in the present study and based on literature, it can be said that CW’s methods would play a major role in the sustainable management of wastewater.

2 illus, 4 tables, 53 ref

001226   VINOD A (Electrical and Electronics Engineering Dep, Marri Laxman Reddy Institute of Technology and Management, Hyderabad, Telangana) : Solar energy conservation and pollution control by employing BWO algorithm. Eco Env Cons 2021, 27-S1, 150-4.

In this article, a novel energy conservation arrangement is employed depending up on the exertion of the solar energy and imperceptible renewable energy systems. The designing and modelling of solar cell is examined with various parameters estimation. In this proposed solar energy conservation and pollution control, black widow optimization algorithm (BWO) is employed to optimize the parameters of the solar module. Due to uneven designs of solar modules the conservation of solar energy is inefficient and such that dependency on the fossil fuels is increasing in our daily life decades, accordingly the environmental pollution is greatly sustained. The performance of solar module energy conservation, it mainly depends on the tuning of algorithm for estimation of parameters related to the solar module and its environmental scheme of exploitation and exploration. In the process of attaining the exact parameters for solar energy conservation, the proposed method outplays the previous existing methods and such that the dependency on fossil fuels is getting reduced thus the pollution control is achieved greatly.

3 illus, 1 table, 17 ref

001216   UDAYAKUMAR J, FATHIMA J, ANAMIKA B, ATHIRA V R (Civil Engineering Dep, TKM Coll of Engineering, Kollam- 691 005, Kerala) : Environmental implications of the soil settlement in Munroe Island, Kollam, Kerala, India. Eco Env Cons 2021, 27-S1, 88-93.

The Munroe island in the Ashtamudi estuary of Kollam district in Kerala is facing the threat of sinking and soil settlement. The main objective of this study is to find out the reasons for the soil settlement in the island. The soil samples were collected from different parts of the island and the organic carbon content in the soil was estimated. An attempt was also made to study the soil breathing in the island. Based on these, the hypothesis that the main reason for soil settling is the near surface oxidation of carbon in the organic soil of the deltaic island was tested and proved correct. The higher concentrations of carbon dioxide emission from the soil were mostly from the locations affected by soil settlement.

8 illus, 9 ref

001186   TEJASWINI V V, MANOGNA K S, DEEKSHITHULU N V, SINDHUJA K (Applied Engineering Dep, Vignan Foundation For Science and Technology, Vadlamudi- 522 213) : Yield response of Okra to different row spacings and fertilizer application methods under drip irrigation system. Eco Env Cons 2021, 27-S2, 270-5.

An experiment was conducted to study the okra yield response (Abelmoschus esculentus L. Moench) to the different methods of fertilizer application (i.e through fertigation tank and by manual application) & row to row spacing during February-May 2017. Two row spacings of 40x60 cm and 50x60 cm were selected. Analysis of the data showed that the response of the okra crop was considered a better combination of 50 x 60 cm through fertigation method compared to manual application. Yield in plot III was observed to be 22% more compared to manual application under same row to row spacing. Yield attributes such as pod weight, pod length and pod perimeter was also observed to be best in spacing of 50 x 60 cm. Similarly plant characteristics namely plant height, root depth and lateral distribution of roots were also found to be highest in 50 x 60 cm by fertigation method.

3 illus, 5 tables, 18 ref

001173   RAVISANKAR N, GNANAKUMAR S (Civil Engineering Dep, Annamalai Univ, Annamalainagar- 608 002, Tamil Nadu) : Comprehensive flood mitigation and management in Velliangal Odai, Veeranam Tank, Cuddalore District, Tamil Nadu State, India. Eco Env Cons 2021, 27-S2, 181-91.

Floods are naturally occurring processes that are difficult to prevent but can be managed in order to reduce its social and economic impacts. Mitigation is defined as a continued action to minimize risk property or human. The Muskingum model is a popular method to analyze the flood routing. The objectives of the study are to study the generating techniques for flood routing and also to evaluate the old used methods, to assess the accuracy of the available flow data and to check the results through basic flood routing methods and to find out the most vulnerable livelihood assess and also factors influencing to occupational and socio migration in the study area. The study area is Velliangal odai, Veeranam Tank, Cuddalore district, Tamilnadu state. The methodology used for this study is Muskingum method. The hydrometric data was applied in the study have been the collected from the public work department in Chidambaram (2001-2018), this data included water levels, inflow and outflow estimation. In this study, Reaches of different lengths were selected to assess the influence of river length in the application of flood routing methods. The Muskingum Parameters for the Velliangal Odai river at varying x calculated as shown in the graph is plotted with [K(Ix+(1"x) Q)] on x-axis and the storages on y-axis. The points indicate the formation of a loop and there is improvement when x tends to zero. In the beginning the loop was narrower at x= 0.35 but in the third trial at x= 0.25 is computed, found satisfactory. Therefore, the correct value of x can be taken as 0.25 for the Velliangal Odai River.

37 illus, 16 ref

001163   PADMAJA M, SANJANA R, PRAYTUSHA K, DASH S, RAJ A, REDDY M K (Computer Science and Engineering Dep, Gandhi Institute of Technology and Management, Visakhapatnam- 530 045) : Assessment of winged jewels in selected areas of Visakhapatnam, India. Eco Env Cons 2021, 27-S2, 116-22.

Butterflies are called as “winged jewels” due to their sparkling and vibrating appearance. They were considered to be biodiversity indicators due to their major role at the base level of the food chain. Due to increase in population and expansion of urban sectors there could be severe threat to richness to these winged jewels. The aim of the present study was to carry out diversity and abundance of the butterfly population in the City of Visakhapatnam. Two green patches of the study area (Indira Gandhi Zoological Park, Kailasagiri Park) were selected to identify butterfly species. A total of 62 species of 5 families were recorded. Family Nymphalidae recorded highest of 22 species were found followed by Lycaenidae (15), Pieridae (15), Papilionidae (7) and Hesperiidae with three species. A seasonal variation among the butterfly population was observed. Post monsoon was found to be good season for the abundance and richness of butterfly’s population compared to pre monsoon season.

1 illus, 2 tables, 24 ref

001128   RAGHAV A, SINGH S K (Environmental Engineering Dep, Delhi Technological Univ, Delhi) : Drinking water quality evaluation for groundwater of Delhi, India using GIS techniques. Eco Env Cons 2021, 27(1), 359-64.

Groundwater is considered to be an important water resources because of it’s widey use in drinking and irrigation purpose. Due to industrialization and urbanization, groundwater quality is deteriorating at a rapid rate. The present study evaluates the groundwater quality of NCT Delhi using drinking water quality parameters with the computation of water quality index (WQI) and coupled with QGIS technique. Raster interpolation technique, Inverse Distance Weighted (IDW) in QGIS software has been used to generate the spatial distribution map of water quality parameters. Six water quality parameters are used to evaluate the suitability of groundwater for the drinking purpose. WQI has been developed using eleven drinking water quality parameters. It was found that the majority of WQI of the study area lies in “poor” to “unsuitable for drinking” category.

8 illus, 4 tables, 8 ref

001125   SINGH M, TIWARI D P, BHAGAT M (Chemical Engineering Dep, Deenbandhu Chhotu Ram Univ of Science and Technology, Murthal- 131 039) : Removal of nickel (ii) ions from aqueous solution using activated carbon developed from Azadirachta indica a low cost adsorbent. Eco Env Cons 2021, 27(1), 339-46.

Present paper deals with the removal of Ni(II) metal ions using activated carbon developed from carbonaceous source material neem leaves (Azadirachta indica) powder as an adsorbent. Heavy metals plays a vital role for proper functioning of biological systems but a large number of disorders arises from their lack or excess. Industrial effluents contain higher concentrations of heavy metals such as Cr, Ar, Cd, Pb, Ti, Hg and Ni that contaminate the water bodies. Adsorption technique was used in this research to extract Ni (II) ions from aqueous solution. Batch experiments were carried out to analyze the influence of different parameters such as solution pH, initial metal ions concentration, adsorbent dosage, contact time and temperature. Fourier-transform infrared spectroscopy (FTIR) and x-ray diffraction (XRD) used to analyze the physiochemical and morphological properties of sample. The scanning electron microscopy (SEM) revealed micro-structural properties of adsorbent sample. Specific surface area of activated carbon developed from neem leaves (Azadirachta indica) was 32.2 m²/g evaluated by BET. It was concluded that the maximum percentage (%) removal of Ni (II) ions was about 80%. The adsorption experimental data was best fitted to Temkin adsorption isotherm model and kinetic data was in a good agreement with pseudo first order kinetic model.

14 illus, 1 table, 34 ref

001091   NAZEER S, SYED M A, SHAIK F (Mechanical and Industrial Engineering Dep, National Univ of Science and Technology, Muscat, Sultanate of Oman) : Bioremediation of metal ions from aqueous solutions using Algae Cladophora sp. Eco Env Cons 2021, 27(1), 108-14.

The efficiency of Cladophora sp. algae, collected from wadi (channel) at Samail, Sultanate of Oman as a biosorbent for the removal of metallic ions from aqueous solutions was investigated. Fourier transform infrared spectrometer analysis (FTIR) showed the presence of carbonyl, ether, amine and alkyl chain stretch functional groups on Cladophora sp. algae. The point of zero charge (pHzpc) for the biosorbent was estimated at pH 7.22. pH increased with contact time and biomass showed higher adsorption capacity within first 24 hours. High metal concentration favors the adsorption of metal ions, calcium (Ca²⁺), copper (Cu²⁺) and magnesium (Mg²⁺) on to the surface of Cladophora sp. algae. Langmuir’sequilibrium isotherm model fitted slightly better with the adsorption data. Copper and magnesium metal ions found to have more affinity towards Cladophora sp. biomass than calcium ions.

19 illus, 1 table, 21 ref

001024   KARTHIKEYAN P, RAJKUMAR M A (Kongu Engineering Coll, Perundurai, Erode) : Farmers participation on tank irrigation water management in Tamil Nadu. Water Energy Int 2021, 63r(10), 20-7.

This study is to compare with system and non system tank farmers. The non system tank farmers do not get adequate water as they depend on their own catchment area. This study is analyses the Farmers Participation in tank Maintenance and Water availability in different tank systems and farms in Madurai district of Tamilnadu. The study reveals that, the Government should initiate more modernized schemes for non system tank farmers. Socio economically poor farmers own the land in tail end areas they belong to lower caste. In a nutshell, in modernized tanks well water level was almost stable compared with non modernized tanks. The water depleted year by year in non modernized tanks In short, modernized tank farmers have got irrigation facility for two crops compared with non modernized tanks irrespective of tank systems. Farmers were not interested to cultivate third crop in system tanks even though water was available in wells. This paper analysis how tank modernization with farmers participation to tank system can help farmers to increase irrigation utility.

2 illus, 8 tables, 8 ref

001019   MURUGAN S S, RAJALAKSHMI S, SELVAKUMAR P (Civil Engineering Dep, Sri Ramakrishna Engineering Coll, Vattamalaipalayam, Coimbatore) : Management of non revenue water in a water distribution system for a municipality in Tamil Nadu. Water Energy Int 2021, 63r(11), 8-12.

Water is the basic element for any living thing to stay alive. In this current scenario, water is consumed in almost all the sectors. Among the various sources of consumption, water provision for drinking is to be given the most priority. And to provide water for the people, an enormous cost is incurred by the water utilities. To provide water connection to all and to maintain a quality water supply system, a good revenue generation is necessary. However, Utilities in most of the countries are facing a huge gap between cost spent on water supply and revenue generated. This paper addresses this problem of having a gap between cost and revenue through assessing the Non-revenue water. Non-Revenue water is assessed in a live water distribution system of a municipality in Tamilnadu. In this paper, the different components of Non-Revenue water are assessed and a strategy is proposed to manage the level of Non-Revenue water in the water distribution system of the study area.

5 illus, 3 tables, 19 ref

001016   GUPTA V (Electronics and Communication Engineering Dep, National Institute of Technology, Kurukshetra, Haryana) : Recent technologies for leak detection in pipeline : A Review. Water Energy Int 2021, 64r(1), 29-37.

Pipeline systems are usually deployed for transporting liquid (e.g., oil, water) in the long run and for a long span. However, with time, they tend to degenerate. Numerous reasons lead to damage to these systems. It is essential to detect and identify the location of leakages timely as it can be dangerous. The new technologies (e.g., Internet of Things, machine learning) is now being employed to detect a leak in pipelines autonomously. In this paper, attempts have been made to study the pipelines' health monitoring systems to ensure their continuous functionality. For this purpose, several pipeline leakage detection methods have been reviewed here. Moreover, the challenges associated with various pipeline health monitoring methods have been identified. Additionally, some of the recent case studies employing Internet of Things technology, robot, and polyvinylidene fluoride wire sensors have been discussed. It is expected that the outcome of this article will be quite useful for assessing the status of the working of the pipeline system, especially in terms of leakage for any project in the future.

1 table, 71 ref

003473   KUMAR M S, RAMANATHAN R, JAYAKUMAR M, YADAV D K (DRDO-Scientific Analysis Group, Delhi - 110 054, Email: r_ramanathan@cb.amrita.edu) : Secret key generation schemes for physical layer security. Def Sci J 2021, 71 (4), 545 - 55.

Physical layer security (PLS) has evolved to be a pivotal technique in ensuring secure wireless communication. This paper presents a comprehensive analysis of the recent developments in physical layer secret key generation (PLSKG). The principle, procedure, techniques and performance metricesare investigated for PLSKG between a pair of users (PSKG) and for a group of users (GSKG). In this paper, a detailed comparison of the various parameters and techniques employed in different stages of key generation such as, channel probing, quantisation, encoding, information reconciliation (IR) and privacy amplification (PA) are provided. Apart from this, a comparison of bit disagreement rate, bit generation rate and approximate entropy is also presented. The work identifies PSKG and GSKG schemes which are practically realizable and also provides a discussion on the test bed employed for realising various PLSKG schemes. Moreover, a discussion on the research challenges in the area of PLSKG is also provided for future research.

3 illus, 5 tables, 45 ref

003471   RAHA K, RAY K P (DRDO-Defence Institute Of Advanced Technology, Pune - 411 025, Email: krishraha@gmail.com) : Designing a cavity backed microstrip antenna with enhanced isolation for the development of a continuous wave ground penetrating radar. Def Sci J 2021, 71 (4), 524 - 34.

This paper presents an improved design of a rectangular microstrip antenna at 920 MHz by backing it with an appropriate cavity wall to enhance the isolation between the transmitter and receiver antenna for use in applications, where the weak received power gets masked by the direct coupled power between two antennas. Antennas having 0.12 λ cavity wall with separation gap of 0.36 λ resulted in an isolation of 52.6 dB at a resonance frequency of 920 MHz with maximum and minimum isolation of 71.4 dB and 49.1 dB, respectively for 5% BW of the antenna designed. These antennas were fabricated and tested, which are used in the development of Continuous Wave Ground Penetrating Radar with an online graphical user interface; leading to the validation of the usefulness of proposed antennas.  The isolation achieved at an optimised separation of the antennas enabled detection of metal targets as small as a bunch of wire buried 20 cm in the soil and non-metal, like wood and plastic buried in soil. It enabled the detection of a circular steel target of radius 12.5 cm buried at a depth of 65 cm in loose semi-dry pebbled soil.

17 illus, 4 tables, 33 ref

003470   JOSE J V, REKH A S, JOSE M J (Karunya Institute of Technology and Sciences, Coimbatore – 641 114, Email: jerryv@karunya.edu.in) : Demonstrating antenna miniaturisation for radiolocation applications using double elliptical patches. Def Sci J 2021, 71 (4), 515 - 23.

Double Elliptical Micro-strip Patch Antenna (DEMPA) is developed out of Double Elliptical Patch (DEP) which is a recently proposed shape of patch. The use of DEP results in higher flexibility in design of patch antenna and thus promotes antenna miniaturisation. The present work is an attempt to demonstrate the miniaturisation of radiolocation antenna through the concept of Design Flexibility (DF). In this paper, optimised neural network model for synthesis of DEMPA has been developed for radiolocation applications for which the earmarked frequency band is 8.50 GHz – 10.50 GHz. With the help of synthesis model, for an arbitrary operational frequency of 9.85 GHz,  radiolocation antennas with effective patch area ranging from 142 mm² to 66 mm² were designed by using DEPs. In this case, the percentage reduction in effective patch area was found to be 53.52%. It shows that double elliptical patches can be employed to develop miniaturised radiolocation antennas. One prototype antenna was fabricated and tested to demonstrate the efficacy of the methodology adopted. The fabricated antenna had resonance at 10.15 GHz with a reflection coefficient of -20.73dB and bandwidth of 3.106 GHz (from 7.458 GHz to 10.564 GHz). Its Fractional Bandwidth was 34.469%. Positive and reasonably good gain was maintained over the entire working band. At resonance, the peak gain was 4.22 dB.The measured characteristics of antenna were in close agreement with the simulated results. The methodology presented in this paper can also be applied to frequency bands for other wireless applications.

6 illus, 4 tables, 36 ref

003466   KUMAR S, INDU S, WALIA G S (DRDO-Scientific Analysis Group, Delhi - 110 054, Email: sumitkr@hotmail.com) : An efficient multistage fusion approach for smartphone security analysis. Def Sci J 2021, 71 (4), 476 - 90.

Android smartphone ecosystem is inundated with innumerable applications mainly developed by third party contenders leading to high vulnerability of these devices. In addition, proliferation of smartphone usage along with their potential applications in diverse field entice malware community to develop new malwares to attack these devices. In order to overcome these issues, an android malware detection framework is proposed wherein an efficient multistage fusion approach is introduced. For this, a robust unified feature vector is created by fusion of transformed feature matrices corresponding to multi-cue using non-linear graph based cross-diffusion. Unified feature is further subjected to multiple classifiers to obtain their classification scores. Classifier scores are further optimally fused employing Dezert-Smarandache Theory (DSmT). Strength of suggested model is assessed both qualitatively and quantitatively by ten-fold cross-validation on the benchmarked datasets. On an average of outcome, we achieved detection accuracy of 98.97% and F-measure of 0.9936

5 illus, 5 tables, 45 ref

003461   MISHRA S, MOHAN S, VISHVAKARMA S K (ndian Institute of Technology, Palakkad - 678 557, Email: santhakumar@iitpkd.ac.in) : Performance investigations of an improved backstepping operational-space position tracking control of a mobile manipulator. Def Sci J 2021, 71 (4), 436 - 47.

This article implies an improved backstepping control technique for the operational-space position tracking of a kinematically redundant mobile manipulator. The mobile manipulator thought-out for the analysis has a vehicle base with four mecanum wheels and a serial manipulator arm with three rotary actuated joints. The recommended motion controller provides a safeguard against the system dynamic variations owing to the parameter uncertainties, unmodelled system dynamics and unknown exterior disturbances. The Lyapunov’s direct method assists in designing and authenticating the system’s closed-loop stability and tracking ability of the suggested control strategy. The feasibility, effectiveness and robustness of the recommended controller are demonstrated and investigated numerically with the help of computer based simulations. The mathematical model used for the computer-based simulations is derived based on a real-time mobile manipulator and the derived model is further verified with an inbuilt gazebo model in a robot operating system (ROS) environment. In addition, the proposed scheme is verified on an in-house fabricated mobile manipulator system. Further, the recommended controller performance is correlated with the conventional backstepping control design in both computer-based simulations and in real-time experiments

14 illus, 4 tables, 37 ref

003457   TRIPATHI S, MOHAPATRA B, TIWARI P, TRIPATHI V S (Electrical and Electronics Engineering Dep, Galgotias Coll of Engineering and Technology, Greater Noida - 201 310, Email: shiveshtripathi@gmail.com) : Multi-mode resonator based concurrent triple-band band pass filter with six transmission zeros for defence/intelligent transportation systems application. Def Sci J 2021, 71 (3), 403 - 9.

A compact and highly selective triple-band bandpass filter (BPF) is designed and presented in this paper. Proposed filter offers low insertion loss, and passband characteristics is achieved by using two coupled MMR multi-mode resonators (MMR1 and MMR2) and an inverted T and circular shape MMRs. The filter operates at frequency 2.43 GHz (Vehicular Communication), 5.91 GHz (ITS band), and 8.86 GHz (satellite communication band). The simulation and measurement results show a minimum insertion loss of 1.6 dB, 0.73 dB, and 2.8 dB for triple-band BPF. The return loss is found to be greater than 13.06 dB, 28.6 dB, and 21.55 dB. It is noted that measurement results are in accordance with the result of electromagnetic simulation. Desired triple-band multi-mode resonators (MMRs) filter characteristics are achieved with six transmission zeroes (TZs). The filter comprises of MMRs which provide small size and control over the spurious frequency. By using a parallel-coupled microstrip line, the first and third passbands are realised. Whereas by using an end-coupled microstrip line, the second passband is recognised. At the input and output ports, the resonator coupling technique is used. By using the anti-parallel microstrip line arrangement, the transmission zero is acquired. The dimensions of the designed filter are 25×16 mm 2

10 illus, 2 tables, 28 ref

003456   KAUSHAL S, KUMAR B, SHARMA P, SINGH D (Electronics and Communication Engineering Dep, Indian Institute of Technology, Roorkee - 247 667, Email: dharmfec@iitr.ernet.in) : Real-time adaptive approach for hidden targets shape identification using through wall imaging system. Def Sci J 2021, 71 (3), 395 - 402.

 In Through-wall Imaging (TWI) system, shape-based identification of the hidden target behind the wall made of any dielectric material like brick, cement, concrete, dry plywood, plastic and Teflon, etc. is one of the most challenging tasks. However, it is very important to understand that the performance of TWI systems is limited by the presence of clutter due to the wall and also transmitted frequency range. Therefore, the quality of obtained image is blurred and very difficult to identify the shape of targets. In the present paper, a shape-based image identification technique with the help of a neural network and curve-fitting approach is proposed to overcome the limitation of existing techniques. A real time experimental analysis of TWI has been carried out using the TWI radar system to collect and process the data, with and without targets. The collected data is trained by a neural network for shape identification of targets behind the wall in any orientation and then threshold by a curve-fitting method for smoothing the background. The neural network has been used to train the noisy data i.e. raw data and noise free data i.e. pre-processed data. The shape of hidden targets is identified by using the curve fitting method with the help of trained neural network data and real time data. The results obtained by the developed technique are promising for target identification at any orientation.

6 illus, 2 tables, 32 ref

003455   MAHAL H S, SINGH B P, KANT R (Metallurgical and Materials Engineering Dep, Punjab Engineering Coll, Chandigarh - 160 012, Email: kravi.iitr@gmail.com) : The effect of co doping on structural, optical and dielectric behaviour of TiO₂ nanoparticles. Def Sci J 2021, 71 (3), 390 - 4.

Chemical precipitation method was used to synthesise pure and Co-doped TiO₂ nanoparticles. The synthesised nanoparticles were studied for its structural optical and dielectric properties. X-Ray diffraction (XRD) confirmed the anatase phase with the tetragonal structure obtained for both samples. No extra peak was obtained in the pattern indicates that cobalt ions were successfully incorporated. The crystallite size of both samples were determined by using Debye-Scherrer’s method, and it was found that it decreases with the dopant addition. UV vis spectroscopy was performed to study the optical properties of both samples. The dielectric constant (εʹ), dielectric loss and ac conductivity (σac) of both samples were studied against the frequency. The dielectric constant, dielectric loss and ac conductivity results showed that Co-doping has a significant effect.

4 illus, 1 table, 14 ref

003454   SINGH R, YADAV S D, SAHOO B K, CHOWDHURY S G, KUMAR A (CSIR-National Metallurgical Laboratory, Jamshedpur - 831 007, Email: abhishek@mnnit.ac.in) : Phase transformation, mechanical properties and corrosion behaviour of 304L austenitic stainless steel rolled at room and cryo temperatures. Def Sci J 2021, 71 (3), 383 - 9.

The present work investigates the effect of rolling (90% thickness reduction) on phase transformation, mechanical properties, and corrosion behaviour of 304L-austenitic stainless steel through cryorolling and room temperature rolling. The processed steel sheets were characterised through X-ray diffraction (XRD), electron backscattered diffraction (EBSD), and vibrating sample magnetometer (VSM). The analysis of XRD patterns, EBSD scan, and vibrating sample magnetometer results confirmed the transformation of the austenitic phase to the martensitic phase during rolling. Cryorolling resulted in improved tensile strength and microhardness of 1808 MPa and 538 VHN, respectively, as compared to 1566 MPa and 504 VHN for room temperature rolling. The enhancement in properties of cryorolled steel is attributed to its higher dislocation density compared to room temperature rolled steel. The corrosion behaviour was assessed via linear polarisation corrosion tests. Corrosion resistance was found to decrease with increasing rolling reduction in both room temperature rolled and cryorolled specimens. 

7 illus, 3 tables, 16 ref

003452   SHARMA A, PANWAR R, KHANNA R (Indian Institute of Information Technology, Jabalpur - 482 005, Email: rpanwar.iitr@gmail.com) : Development of single-layered, wide-angle, polarisation-insensitive metamaterial absorber. Def Sci J 2021, 71 (3), 372 - 7.

The simultaneous achievement of multiband absorption, polarisation-insensitive, and angularly stable absorber is a difficult job. Therefore, in this article, an efficient single-layered absorber is designed, critically analysed, fabricated, and experimentally validated. The proposed model incorporates eight sectors loaded a circle inside the square. The four discrete absorption peaks are observed at 4.4 GHz, 6.0 GHz, 14.1 GHz, and 16.0 GHz manifesting absorption intensities of 94%, 84%, 82%, and 92%, respectively. Parametric studies have been also exercised to investigate the influence of discrete geometrical design variables on the proposed absorber. The proposed structure is symmetrical in geometry, consequence in polarisation-independent behaviour. The absorption mechanism is also explained by analysing the surface current, electric field, and magnetic field distributions. Besides, the complex electromagnetic parameters are extracted to realise the absorption phenomenon. Additionally, to validate the simulated results, an optimal sample is fabricated and the measured response is well-matched with simulated ones.

10 illus, 3 tables, 19 ref

003451   VERMA A, NARANG N, SINGH D, VARMA G D (Indian Institute of Technology Roorkee, Roorkee - 247 667, Email: dharm@ec.iitr.ac.in) : Development of E-waste based composite microwave absorbing material. Def Sci J 2021, 71 (3), 365 - 71.

Microwave absorbing materials (MAMs) are widely researched due to their use in many practical applications including both civil and defense sectors. Irrespective of the humongous efforts of various researchers, the development of a wide bandwidth, thin coating thickness, and low-cost microwave absorber is still a challenging task. The existing materials have not been able to meet all the specifications together at once and require a trade-off in the performance parameters. In this paper, we have empirically corroborated a cost-effective technique using E-waste material for synthesising composite MAM. It is herein shown that the addition of different wt% of copper, graphite, and titanium dioxide in the E-waste successfully resulted in enhanced absorption due to altered electrical properties of the E-waste suitable for microwave absorption. The multilayering technique with the help of a genetic algorithm has also been used to broaden the bandwidth. As a result, a three-layer MAM with the total coating thickness of 3.2 mm has been synthesised showing the wideband absorption bandwidth of 8.47 GHz in the frequency range from 6.92 to 15.39 GHz. The results suggested that microwave absorption of E-waste can be drastically improved by appropriately tailoring electrical parameters such as permittivity and permeability.

7 illus, 3 tables, 24 ref

003449   SINGH R, NARANG N, SINGH D, GUPTA M (Computer and Communication Engineering Dep, Manipal Univ Jaipur, Jaipur - 303 007, Email: dharm@ec.iitr.ac.in) : Compact wideband microstrip patch antenna design for breast cancer detection. Def Sci J 2021, 71 (3), 352 - 8.

The current breast cancer detection techniques are mostly invasive and suffer from high cost, high false rate and inefficacy in early detection. These limitations can be subdued by the development of a non-invasive microwave detection system whose performance is predominantly dependent on the antenna used in the system. The designing of a compact wideband antenna and matching its impedance with breast phantom is a challenging task. In this paper, we have designed a compact antenna matched with the breast phantom operating in wideband frequency from 1 to 6 GHz capable to detect the dielectric (or impedance) contrast of the benign and malignant tissue. The impedance of the antenna is matched to a cubically shaped breast phantom and a very small tumor (volume=1 cm3). The antenna is tuned to the possible range of electrical properties of breast phantom and tumour (permittivity ranging from 10 to 20 and conductivity from 1.5 to 2.5 S/m). The return loss (S₁₁), E-field distribution and specific absorption rate (SAR) are simulated. The operating band of antenna placed near the phantom without the tumor was found to be (1.11-5.47)GHz and with tumor inside the phantom is (1.29-5.50)GHz. Results also show that the SAR of the antenna is within the safety limit.

8 illus, 2 tables, 18 ref

003448   REDDY V V, ANSARI M A, THOTTAPPAN M (Electronics Engineering Dep, Indian Institute of Technology, Email: mthottappan.ece@iitbhu.ac.in) : Simulation investigations of high power overmoded relativistic backward wave oscillator with trapezoidal resonant reflector. Def Sci J 2021, 71 (3), 346 - 50.

An S-band high power relativistic backward wave oscillator using a trapezoidal resonant reflector and overmoded slow-wave structure is demonstrated by finite difference time domain based Particle-In-Cell code. The trapezoidal resonant reflector and slow-wave structure are chosen to improve the RBWO power handing capability to gigawatt (GW). The Trapezoidal resonant reflector enhances the pre-modulation during electron beam propagation, thus increasing the generated RF signal overall efficiency and coherency. The particle-in-cell simulation generated an RF output power ~5.4 GW in TM₀₁ mode at ~3.6 GHz in a 2.0 T magnetic field and developed a 13.5 kA current for a 1.2 MV DC cathode voltage. The power conversion efficiency is achieved as ~33 %. Further, the influence of different design parameters on frequency, RF output power, and efficiency are analysed through Particle-In-Cell simulations.

12 illus, 2 tables, 11 ref

003447   BAGHEL G S, KARTIKEYAN M V (Electronics & Communication Engineering Dep, National Institute of Technology, Silchar - 788 010, Email: gauravsingh.5290@ieee.org) : Output system of a 42/84 GHz, 0.5 MW, dual regime gyrotron. Def Sci J 2021, 71 (3), 341 - 5.

In this paper, the design studies of the output system are carried out for a dual regime Gyrotron in the context of India’s requirement of clean energy. This design study consists of a dimpled wall quasi-optical launcher (QOL) and RF window. After proper coupling of energy from beam to RF wave, the amplified wave need to be down-convert in a Gaussian-like beam (much simplified lower order). The launcher is designed with a commercial software LOT/Surf3d. This Gaussian-like mode coming out from the gyrotron vacuum system through the RF window is coupled to the corrugated waveguide using Matching Optic Unit (MOU) section. The complete design of the RF window is carried out using gyrotron design suite version 4.0 (GDSv4.0 2016).

9 illus, 3 tables, 8 ref

003445   BANSIWAL A, RAINA S, VINOY K J, DATTA S K (DRDO-Microwave Tube Research and Development Centre, Bengaluru - 560 013, Email: ashokbansiwal@gmail.com) : Effect of beam-tunnels on resonant frequency of cylindrical reentrant cavity. Def Sci J 2021, 71 (3), 332 - 6.

Analytical formulations for the resonant frequency of a reentrant cavity for klystron are available in the literature only for such cavities having a single beam-tunnel. An improved analytical formulation has been proposed in this paper for the calculation of cavity gap-capacitance of reentrant cavities having single and multiple beam-tunnels and its effects on the resonant frequency are studied. The results obtained through analysis have been validated against those obtained from the 3D electromagnetic field simulations and measurements. The proposed analytical formulation provides good estimation of resonant frequency of cavity with single and multiple beam-tunnels.

3 illus, 1 table, 11 ref

003440   KUMAR A, TRIPATHI P, DWIVEDI S, JAIN P K (Electronics Engineering Dep, Indian Institute of Technology, Varanasi - 221 005, Email: arjunkr.rs.ece15@itbhu.ac.in) : Analysis, design, and simulation of an axially-partitioned dielectric-loaded bi-frequency MILO. Def Sci J 2021, 71 (3), 309 - 14.

In  this  paper,  a  bi-frequency  magnetically  insulated  line  oscillator  (MILO)  was  proposed  and  designed.  The bi-frequency  MILO  proposed  has  two  axially  partitioned  slow-wave  interaction  structures  (SWS)  and  the  second SWS  is  dielectric-loaded  to  create  the  frequency  shift  in  the  resonant  frequency.  The  conventional  MILO  device design methodology was followed along with two SWSs separated by a segregation cavity. The dispersion relation of the dielectric-loaded SWS was calculated using an equivalent circuit approach. Furthermore, the cold analysis was carried out to find the energy stored in the different SWSs to validate the device oscillation frequency. The beam wave interaction behaviour and device RF output performance were investigated through 3D PIC (Particle-in-cell) simulation  for  typical  diode  voltage  of  550  kV,  and  current  48  kA,  respectively.  Simulation  results  illustrate  that the proposed MILO generates RF peak power of ~3.5 GW at frequencies 3.62 GHz and 3.72 GHz. The conversion efficiency of the device was ~13.25%

10 illus, 1 table, 14 ref

003437   KARN P K, KUMAR P, DAS S (Space Engineering and Rocketry Dep, Birla Institute of Technology Mesra, Ranchi - 835 215, Email: phdser10051.16@bitmesra.ac.in) : Asymmetrical vortex over slender body: A computational approach. Def Sci J 2021, 71 (2), 282 - 8.

Computational investigations were carried out on an ogive-cylinder configuration having a slenderness ratio of 7.5. The geometry of the nose tip was generated based on the physical geometry of the nose tip observed under a scanning electron microscope. Time-dependent simulations were performed on the slender body at a diameter Reynolds number of 3.0×104. Results indicated that the onset of vortex asymmetry was mainly due to the micro-tip imperfection existing at the tip. It was also observed that the variation in the roll angle of the model affected the flow physics largely which has been experimentally observed by several researchers in the past. The computed results were in better agreement with the referenced experimental data.

13 illus, 11 ref

003436   GÖZDE H, ÖZDEN S (National Defence University, Turkey, Email: sozden@kho.edu.tr) : Adaptive true proportional navigation guidance based on heuristic optimisation algorithms. Def Sci J 2021, 71 (2), 271 - 81.

The PN-guidance (Proportional Guidance) still continues to be improved, because it is the simplest, cheapest and most reliable algorithm. One of the most important techniques to improve PN-guidance is to adapt the navigation constant depending on time. In this study, first, the entire adaptation methods for PN-guidance are classified, then the  adaptation  process  is  online  achieved  by  using  heuristic  optimisation  during  guiding  the  missile.  The  novelty of this study is that the heuristic optimisation approach is used at the first time to update the navigation constant of PN-guidance. It is considered that having short program code, fast convergence speed and just simple algebraic computations  without  derivative  are  vital  advantages  of  heuristic  algorithms  using  into  missile  systems.  In  this scope,  an Adaptive  True-PN  (ATPN)  guidance  algorithm  is  designed  by  optimising  navigation  constants  varying according to the target behaviour. The results show that while the acceleration gap of the pitch axis decreases 21.8%, the  acceleration  gap  of  yaw  axis  reduces  39.68%.  These  reductions  mean  that  while  the  missile  guided  by ATPN is  maneuvering, it  is  exposed  to  less  acceleration and  less  strain.

8 illus, 5 tables, 26 ref

003434   MAI V, LUU X, DAO C, LE D (Civil Engineering Dep, Kumoh National Institute of Technology, South Korea, Email: maivietchinh@lqdtu.edu.vn) : Investigate the structural response of ultra high performance concrete column under the high explosion. Def Sci J 2021, 71 (2), 256 - 64.

Most of the structures that are damaged by an explosion are not initially designed to resist this kind of load. In  the  overall  structure  of  any  building,  columns  play  an  important  role  to  prevent  the  collapse  of  frame  structure under blast impact. Hence, the main concept in the blast resistance design of the building is to strengthen the blast loading  capacity  of  the  column.  In  the  present  study,  the  dynamic  analysis  and  numerical  model  of  Ultra  High Performance  Concrete  (UHPC)  column  under  high  explosive  load,  is  presented.  Based  on  the  Johnson  Holmquist 2  damage  model  and  the  subroutine  in  the ABAQUS  platform,  a  total  of  twenty  numerical  models  of  the  UHPC column  were  calculated. The  objective  of  the  article  is  to  investigate  the  structural  response  of  the  UHPC  column and locate the most vulnerable scenarios to propose necessary recommendations for the UHPC column in the blast resistance design. The input parameters, including the effect of various shapes of cross-section, scaled distance, steel reinforcement ratio, and cross-section area, are analysed to have a better understanding of the UHPC column subjected  to  the  blast  load.  Based  on  the  results  of  this  study,  the  UHPC  circular  column  was  demonstrated  to achieve  great  blast  resistance  capacity.  Details  of  the  numerical  data,  and  the  discussion  on  the  important  results, are  also  provided  in  this  paper.

6 illus, 6 tables, 34 ref

003433   SINGH S, KHAN D ( Mechanical Engineering Dep, Indian Institute of Technology, Varanasi - 221 005, Email: dkhan.mec@itbhu.ac.in) : Crack - tip radius effect on fatigue crack growth and near - tip fields in plastically compressible materials. Def Sci J 2021, 71 (2), 248 - 55.

Motivated by the prospective uses of plastically compressible materials such as, metallic and polymeric foams, transformation toughened ceramics, toughened structural polymers etc., the present authors investigate the crack-tip radius effect on fatigue crack growth (FCG) of a mode I crack and near-tip stress-strain fields in such plastically compressible  solids.  These  plastically  compressible  materials  have  been  characterised  by  elastic-viscoplastic constitutive equations. Simulations are conducted for plane strain geometry with two different hardness functions: one is bilinear hardening and the other one is hardening-softening-hardening. It has been observed that plastic compressibility as well as strain softening lead to significant deviation in the amount of crack growth. It has further been revealed that the nature of FCG is appreciably affected by initial crack-tip radius. Even though it may look from outside that the increase in tip radius will lead to decrease in FCG, but the nature of FCG variation with respect to tip radius is found to be a combined effect of tip radius, plastic compressibility and work or strain softening etc. As to be expected when the crack-tip radius is low (smallest of the expounded variation of the present study), the rate of FCG is found to be maximum for the bilinear hardening material though the nature of FCG variation is different in plastically incompressible and compressible solids. In sharp contrast, when the material exhibits work or strain softening, the FCG rate is found to be dependent on the instantaneous crack-tip radius. For instance, as a quantitative  comparison  in  the  present  study,  after  the  end  of  5th  cycle,  the  normalised  crack-tip  extension  for  the bilinear material (plastically compressible) corresponding to the smallest tip radius is 2.9 whereas the same for the largest tip radius is 1.9. Conversely, for the material (plastically compressible) that exhibits strain softening, the corresponding  tip  extension values  are  1.0  and  2.7  for  the  same  smallest  and  largest  radii, respectively.

13 illus, 23 ref

003428   MISHRA N K, KUMAR A, CHOUDHURY K (Weaponsand Electronics Systems Engineering Establishment, New Delhi - 110 066, Email: narendra.lal@hqr.drdo.in) : Deep convolutional neural network based ship images classification. Def Sci J 2021, 71 (2), 200 - 8.

Ships are an integral part of maritime traffic where they play both militaries as well as non-combatant roles. This vast maritime traffic needs to be managed and monitored by identifying and recognising vessels to ensure the maritime safety and security. As an approach to find an automated and efficient solution, a deep learning model exploiting convolutional neural network (CNN) as a basic building block, has been proposed in this paper. CNN has been predominantly used in image recognition due to its automatic high-level features extraction capabilities and exceptional performance. We have used transfer learning approach using pre-trained CNNs based on VGG16 architecture to develop an algorithm that performs the different ship types classification. This paper adopts data augmentation and fine-tuning to further improve and optimize the baseline VGG16 model. The proposed model attains an average classification accuracy of 97.08% compared to the average classification accuracy of 88.54% obtained from the baseline model

12 illus, 4 tables, 23 ref

003427   TANDON R, GUPTA P K (Computer Science and Engineering Dep, Jaypee Univ of Information Technology, Solan - 173 234, Email: righatandon@gmail.com) : A novel pseudonym assignment and encryption scheme for preserving the privacy of military vehicles. Def Sci J 2021, 71 (2), 192 - 9.

In this digital era, security has become one of the important topics of concern, and things become more critical for military vehicles where safety plays a vital role. In this paper, we have discussed a pseudonym-based approach that  preserves  the  real  identity  of  military  vehicles.  This  paper  also  focuses  on  military  vehicles’  location  privacy by  deploying  a  novel  pseudonym  assignment  and  encryption  schemes.  The  proposed  security  scheme  is  based  on a  hybrid  approach  of  matrix  array  symmetric  key  and  the  intelligent  water  drop  scheme. After  implementing  the proposed  security  scheme,  each  military  vehicle  will  obtain  its  pseudonym  for  hiding  their  original  identities. The proposed algorithm effectively manages pseudonym generation and change requests for the local region and inter-region  environment.  The  proposed  security  scheme  not  only  provides  secure  communication  and  preservation  of location privacy of military vehicles but also ensures their security against various attacks. Finally, the time efficiency of proposed algorithms is obtained for both local and inter-region requests. Comparative analysis shows that the proposed scheme is more efficient than other existing techniques.

7 illus, 25 ref

003423   SAGAR C K, PRIYADARSHINI A, GUPTA A K (Mechanical Engineering Dep, BITS-Pilani, Hyderabad Campus - 500 078,, Email: amrita@hyderabad.bits-pilani.ac.in) : Experimental investigations on the effect of tungsten content on the machining behaviour of tungsten heavy alloys. Def Sci J 2021, 71 (2), 162 - 70.

The present work attempts to assess the machinability of tungsten heavy alloys (WHAs) with varying tungsten content in terms of different machining variables under varied cutting conditions. It is observed that the feed rate has a significant effect on the machining characteristics, whereas the effect of rake angle appears to be marginal. With increase in W content both cutting force and material removal rate increase, whereas surface roughness decreases. Since WHAs are difficult to machine, an additional objective of the study is to optimise machining parameters. An optimal  balance  of  the  experimental  cutting  parameters  using  Grey  relational  analysis  has  been  achieved,  which can be effectively employed for the machining of the alloys with close dimensional tolerances and desirable surface finish.

11 illus, 6 tables, 22 ref

003419   TIWARI B K, SHARMA R (Ocean Engineering Dep, Indian Institute of Technology Madras, Chennai - 600 036, Email: rajivatri@iitm.ac.in) : Study on system design and integration of variable buoyancy systems for underwater operation. Def Sci J 2021, 71 (1), 124 - 33.

This paper presents the design and analysis of the ‘Variable Buoyancy System (VBS)’ for depth control which is an essential operation for all underwater vehicles. We use the ‘Water Hydraulic Variable Buoyancy System (WHVBS)’ method  to  control  the  buoyancy  and  discuss  details  of  the  system  design  architecture  of  various  components  of VBS. The buoyancy capacity of the developed VBS is five kilograms and the performance of the VBS in standalone mode is analysed using numerical simulation. Presented VBS is operable to control the buoyancy up to sixty meters of depth and it can be directly installed to medium size UVs. Simulation results show that the developed VBS can reduce the energy consumption significantly and higher in each cycle (i.e. descending and ascending) of the same VBS  in  standalone  mode  being  operated  with  either  propeller  or  thruster  for  sixty  meters  depth  of  operation.  Our results conclude and demonstrate that the designed VBS is effective in changing the buoyancy and controlling the heave velocity efficiently and this serves the purpose of higher endurance and better performances desired in rescue/attack operations related to the UVs both in civilian and defense domains.

9 illus, 2 tables, 25 ref

003418   KAMAL S, CHANDRAN C S, SUPRIYA M H (Electronics Dep, Cochin Univ of Science and Technology,, Kochi - 682 022, Email: surajkamal@cusat.ac.in ) : Passive shallow water automated target recognition using deep convolutional bi-directional long short term memory. Def Sci J 2021, 71 (1), 117 - 23.

The  extremely  challenging  nature  of  passive  acoustic  surveillance  makes  it  a  key  area  of  research  in  Naval Non-Co-operative  Target  Recognition  especially  in  Anti-Submarine  Warfare  systems.  In  shallow  waters,  the complex  acoustics  due  to  the  highly  varying  ambient  background  noise  as  well  as  the  multi-modal  propagation  in the surface-bottom bounded channel makes surveillance even difficult. In this work, an ensemble of Convolutional Neural Networks and Bidirectional Long Short Term Memory stages employing soft attention is used to effectively capture  the  spectro-temporal  dynamics  of  the  target  signature.  In  order  to  alleviate  the  overall  computational  cost associated  with  the  optimal  model  search  in  the  extensive  hyperparameter  space,  a  recursive  model  elimination scheme,  making  frugal  use  of  the  available  resources,  is  also  proposed.  Experimental  analysis  on  acoustic  target records,  collected  from  the  shallows  of Arabian  Sea,  has  yielded  encouraging  results  in  terms  of  model  accuracy, precision and  recall.

6 illus, 2 tables, 18 ref

003415   MURALIDHARAN M, PALANI I A (Mechatronics and Instrumentation Laboratory, Indore - 453 552, Email: muralidharanporthy@gmail.com) : Development of subcarangiform bionic robotic fish propelled by shape memory alloy actuators. Def Sci J 2021, Vol 71 (1), 94 - 101.

In this paper, a shape memory alloy (SMA) actuated subcarangiform robotic fish has been demonstrated using a spring based propulsion mechanism. The bionic robotic fish developed using SMA spring actuators and light weight 3D printed components can be employed for under water applications. The proposed SMA spring-based design without conventional motor and other rotary actuators was able to achieve two-way shape memory effect and has reproduced the subcarangiform locomotion pattern. The positional kinematic model has been developed and the dynamics of the proposed mechanism were analysed and simulated using Automated Dynamic Analysis of Mechanical Systems (ADAMS). An open loop Arduino-relay based switching control has been adopted to control the periodic actuation of the SMA spring mechanism. The undulation of caudal fin in air and water medium has been analysed. The caudal fin and posterior body of the developed fish prototype have taken part in undulation resembling subcarangiform locomotion pattern and steady swimming was achieved in water with a forward velocity of 24.5 mm/s. The proposed design is scalable, light weight and cost effective which may be suitable for underwater surveillance application.

10 illus, 3 tables, 36 ref

003413   NIRANJAN R K, RAO C B R, SINGH A K (ECE Dep, National Institute of Technology, Warangal - 506 004, Email: niranjanrk2004@gmail.com) : FPGA based identification of frequency and phase modulated signals by time domain digital techniques for ELINT systems. Def Sci J 2021, Vol 71 (1), 79 - 86.

In this paper, a decision tree algorithm based on time-domain digital technique is developed for the identification and classification of diverse radar intra-pulse modulated signals for the electronic intelligence system in real-time. This includes linear frequency modulation, non-linear frequency modulation, stepped frequency modulation and bi-phase modulation. The received signal is digitised and the instantaneous phase and high accuracy instantaneous frequency are estimated. The instantaneous amplitude is also estimated to get the start and stop of the pulse. Instantaneous parameters are estimated using a moving autocorrelation technique. The proposed algorithm is employed on the instantaneous frequency and the modulation is identified. The modulation type and modulation parameter are important for unique radar identification when similar radars are operating in a dense environment. Simulations are carried out at various SNR conditions and results are presented. The model for algorithm is developed using a system generator and implemented in FPGA. These results are compared when the proposed algorithm is used with the existing digital in-phase and quadrature-phase (DIQ) technique of instantaneous frequency and amplitude estimation.

8 illus, 4 tables, 32 ref