016774   Adami A;Mortazavi M;Nosratollahi M (NO, Amirkabir Univ of Technology, Tehran, Iran, Email: aha.aerospace@aut.ac.ir ) : Multidisciplinary approach to materials selection for bipropellant thrusters using ablative and radiative cooling. Sadhana 2016, 45(1), 87-96.

Reduction of costs is a main consideration in every space mission, and propulsion system is an important subsystem of those missions where orbital maneuvers are considered. Lighter propulsions with higher performance are necessary to reduce the mission costs. Bipropellant propulsions have been widely used in launch vehicles and upper-stages as well as deorbit modules because of better performances in comparison with other propulsion systems. Unfortunately heat transfer and thermal control limit bipropellant propulsion performance and maximum performance cannot be achieved. Well-known cooling methods such as regenerative and film cooling increase the cost using extra equipment and high temperature materials. In this paper, a new approach for cooling is presented based on combined ablative and radiative cooling. Governing equations are derived for two or three layers of thermal protection system (TPS) to optimize the TPS mass. The first layer is used as an ablative layer to control the temperature where the second and third layers are used as an insulator to control the heat fluxes. Proposed cooling method has been applied for two real bipropellant thrusters. According to the results, the presented algorithm can suitably predict the heat fluxes and satisfy the wall temperature constraint. Then, the algorithm has been used to minimize the wall temperatures as low as possible and replace high temperature materials (platinum alloy) with common materials (composite or steel). It is shown that selection of TPS materials affects the TPS mass and Isp simultaneously, but conversely. Best solution should be derived by trading off between structure temperature (cost), Isp (performance), and TPS thicknesses (geometry). Multidisciplinary approach to TPS and structure material selection of a bipropellant thruster is presented for a case study. It has been shown that mass and performance penalties of using TPS are acceptable, considering the advantages of using steel alloy instead of platinum alloy.

10 illus, 2 tables, 21 ref

016773   Abdulrahman W S;Naimee K A A;Eisa A H (Laser Institute, Sudan Univ of Science and Technology, Khartoum, Sudan, Email: rabab_eisa99@sustech.edu) : Chaos generation of modulated optoelectronic feedback in semiconductor laser. Int J pure appl Sci Technol 2015, 30(2), 6-12.

Nonlinear dynamics of a delayed optoelectronic feed back with directly modulated semiconductor laser are studied numerically. The effects of changing the bias current of the delayed modulated optoelectronic feedback with small modulation factor producing chaotic outputs from lasers Diode with nonlinear gain reduction in its optimum value range is investigated. The beginning of transition from periodic state to the chaotic state when bias current (δ = 1.01402) was observed. The chaotic dynamics is completely determined by the variation of the injecting bias current.

2 illus, 1 table, 31 ref

016772   Abdulrahman W S;AlNaimee K A;Eisa A H (Laser Institute, Sudan Univ of Science and Technology, Khartoum, Sudan, Email: rabab_eisa99@sustech.edu) : Chaos generation of modulated optoelectronic feedback in semiconductor laser. Int J pure appl Sci Technol 2015, 31(1), 6-12.

Nonlinear dynamics of a delayed optoelectronic feed back with directly modulated semiconductor laser are studied numerically. The effects of changing the bias current of the delayed modulated optoelectronic feedback with small modulation factor producing chaotic outputs from lasers Diode with nonlinear gain reduction in its optimum value range is investigated. The beginning of transition from periodic state to the chaotic state when bias current (δ = 1.01402) was observed. The chaotic dynamics is completely determined by the variation of the injecting bias current.

2 illus, 1 table, 31 ref

015820   Ying X;Pu Y;Li Z;Liu Z;Jiang Y (School of Optoelectronic Information, Univ of Electronic Science and Technology of China, No. 4 Section 2 North Jianshe Road, Chengdu, Sichuan 610054, China, Email: liuzhijun@uestc.edu.cn) : Absorption enhancement of graphene salisbury screen in the mid-infrared regime. J Optics 2015, 44(1), 59-67.

As an emerging optoelectronic material, graphene has exhibited negligible absorption in the mid-infrared due to its Drude-like behavior of free electrons. For this reason, existing graphene-based Salisbury screens with enhanced graphene absorption have been limited to terahertz frequencies, and are experiencing difficulty to extend to higher frequency region. We propose to utilize graphene interband conductivity instead of the commonly used intraband conductivity to realize graphene-based Salisbury screens in the mid-infrared. Distinct mid-infrared absorption features in graphene-based Salisbury screens are investigated numerically and analytically by means of transfer matrix method. In contrast to terahertz absorption arising from intraband transition, the enhanced absorption of graphene in the mid-infrared is dominated by the interband transition. For a single layer of graphene on top of a metallic plane, peak absorptions of 10% are obtained at normal incidence, and nearly perfect absorptions close to 1 are achieved at near grazing angle for incident s-polarization. To further enhance the perfect absorption over wider incident angles, a graphene-dielectric multilayer stack is proposed and analyzed. These results are relevant to graphene optoelectronics for mid-infrared applications.

7 illus, 76 ref

015819   Xu F;Xian-Song X;Chen J;Wei-Liang J (Institute of Structural Engineering, Zhejiang Univ, Hangzhou-310 058, China) : Behavior of PVA fiber concrete under freezing and thawing cycles. Indian J Engng Mater Sci 2015, 22(6), 693-700.

In this study, the effect of polyvinyl alcohol (PVA) fiber on the behavior of concrete under freeze-thaw condition is investigated. Experimental investigations are conduct to measure the workability, compressive strength, bending strength, total charge passed and frost resistance of PVA fiber concrete in fresh water and NaCl solution under freezing and thawing cycles. The relative dynamic modulus of elasticity and the relative mass change of specimens at each cycle are measured. In addition, the surface deterioration of concrete specimens is also observed. Specimens with different volume content of fiber are tested in order to find the optimization PVA fiber content for frost resistance. Six series of specimens with PVA fiber volume content of 0%, 0.1%, 0.25%, 0.5%, 0.75% and 1.0% are tested. Finally, a model considering internal crack healing and cracking property of fiber concrete is proposed in this study. It is shown that the proposed model is able to predict the test results with reasonable accuracy.

9 illus, 4 tables, 17 ref

015818   Vishnoi R K (NO, , THDC India Ltd., Rishikesh) : Risk allocation provisions in the EPC contract documents for the vishnugad pipalkoti hydropower project. Wat Energy int 2015, 58(9), 52-8.

1 ref

015817   Thakur S;Chauhan S R (Mechanical Engineering Dep, AP Goyal Shimla Univ, Shimla-171 009, Email: sunilthakur.nith@gmail.com) : Experimental investigation of cenosphere particulate filled E-glass fiber reinforced vinylester composites under dry and water lubricated sliding conditions. Indian J Engng Mater Sci 2015, 22(6), 669-78.

Aim of this work is to study the effect of cenosphere particulate on the tribological characteristics of glass fiber reinforced vinylester composites under dry and water lubricated sliding conditions. A synergistic effect is found for the combination of fiber and filler which lead to the improved tribological properties under dry and water lubricated sliding conditions. Effects of applied normal loads, sliding speeds and particle content on the tribological behaviour are also discussed. The experimental results show that the coefficient of friction and specific wear rate decrease with the increase in applied normal load and sliding speed. The experimental results also show that the composites exhibit lower coefficient of friction and lower wear resistance under water lubrication condition than under dry sliding. To validate the experimental data the morphologies of the worn surfaces are carried by means of scanning electron microscope (SEM).

10 illus, 1 table, 26 ref

015816   Sri Jahnavi V;Ahamed S F (ECE Dep, V R Siddhartha Engineering College, Vijayawada) : Smart wireless sensor network for automated greenhouse. IETE J Res 2015, 61(2), 180-5.

Greenhouse is an enclosed structure that provides micro-climate for the plant growth. This paper presents the design of a wireless sensor network that provides real-time monitoring of temperature, humidity and soil moisture of a greenhouse. An automated control system for managing these micro-climate parameters is developed to optimize the parameters and use of water. The sensor node developed handles the data from the sensors and triggers actuators based on the threshold algorithm programmed into the microcontroller. The gateway receives the sensor data and control information through Zigbee and transmits the data to the web application for remote monitoring. The monitor software provides network view with nodes and their information. Information management system is also designed to monitor the data at any required time.

7 illus, 14 ref

015815   Sondhi S;Hote Y V (Electrical Engineering Dep, Indian Institute of Technology, Roorkee) : Fractional- order PI controller with specific gain-phase margin for MABP control. IETE J Res 2015, 61(2), 142-53.

Mean arterial blood pressure (MABP) is one of the most important clinical parameters which is required to be controlled very accurately. Therefore, it is very essential to have an efficient and precise control strategy for regulating the MABP in various clinical conditions, which can work well in uncertain operating environment, and also show good disturbance rejection. Although the fractional-order control scheme has evolved as a strong control strategy in recent times, the design techniques available in the literature are mathematically very complex and hence limit the usage of fractional-order controllers. Moreover, it is observed that the gain and phase margin based techniques that exist in the literature for integer order systems are not completely applicable to the fractional-order systems. Therefore, in this paper, a design scheme is proposed for fractional-order PI controller based on gain and phase margins for controlling the MABP. The beauty of the proposed technique is that the controller designed is found to give better disturbance rejection than the conventional proportional integral (PI) or the IMC-PI controllers for nominal as well as the sensitive and insensitive patients. Thus, the technique proposed here gives the dual advantage of computational simplicity as well as robust controller performance.

11 illus, 3 tables, 44 ref

015814   Singh S P;Srikant K;Jairaj K S (NO, , ) : Motor control circuits used in automatic sun tracking systems. J Instrum Technol Innovation 2016, 6(1), 43-60.

Sun tracking systems provide excellent values of energy gain when compared to fixed photovoltaic (PV) systems. One of the prominent blocks of an active sun tracking system (ASTS) is the motor drive control circuit. This circuit controls motor movement and aligns the PV panel to remain normal to incident solar radiation during all times of the day. The motor drive mechanism includes an electronic circuit that accurately controls the movement of a tracking motor using closed loop or open loop control systems. Precise alignment of the PV panel for correctly tracking the sun throughout the day depends on the performance of the motor control circuit. This review paper focuses on the different types of sun tracking systems used by researchers all over the world and the various types of motor control circuits used in them. It also compares their performance, relative merits and demerits based on their operating principle.

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015813   Silkander A A;Prasad B R (Electrical Engineering Dep, Indian Institute of Technology Roorkee, Roorkee, India) : Novel order reduction method using cuckoo search algorithm. IETE J Res 2015, 61(2), 83-90.

In this paper, a novel method is presented to obtain stable reduced-order model of higher order linear time invariant continuous systems using optimization technique. In order to perform optimization, a new meta-heuristic search algorithm, called Cuckoo Search (CS) is applied which is inspired by the natural behaviour of cuckoo species including the Levy flight behaviour of some birds and fruit flies. The effectiveness of the proposed method is supported by some numerical examples of single input single output (SISO) systems and the results are compared with other well-known methods available in the literature in terms of most popular performance indices like integral square error, integral absolute error, and integral time absolute error. The method is extended for multi input multi output (MIMO) systems also.

3 illus, 2 tabls, 38 ref

015812   Selvi S R;Baskaran R (NO, Sri Venkateswara College of Engineering, Pennalur, Sriperambudur-602 117, Email: selvitech@gmail.com) : Solar photovoltaic-powered membrane distillation as sustainable clean energy technology in desalination. Curr Sci 2015, 109(7), 1247-54.

Present article discusses the application of a new technology using solar photovoltaic (PV) cell coupled with membrane distillation (MD) in the desalination of tap water. Salinity decreases the palatibility of water and causes long-term health issues. MD is the most promising technology to provide safe and clean drinking water to households and for other applications in small quantities. It consumes less energy than the existing commercial brackish water reverse osmosis (RO; pressure-driven) desalination technology (48%) used for the production of drinking water. A large population in India relies on tap water, groundwater, surface water, deep well water and municipal water for drinking and domestic utilization. These sources are highly contaminated due to the presence of harmful metals like fluoride and arsenic causing serious health hazards. The present study compares water quality analysis by chemical methods of both RO and solar PV-driven MD technology. The quality of distillate obtained by MD is excellent and this has been proved by the results of chemical analysis of water. Thermal efficiency of MD operating with solar PV cells and others operated purely by conventional mode is calculated and the results are compared. The study shows higher production of drinking water for solar PV-driven MD.

7 illus, 4 tables, 20 ref

015811   Sastry M R C;Prasad B V S S S;Gupta A V S S K S (Mechanical Engineering Dep, Gudlavalleru Engineering College, Gudlavalleru-521 356, Email: mrchsastry@gmail.com) : Experimental and computational study of fluid flow on a flat plate with three rectangular impinging slot jets. Indian J Engng Mater Sci 2015, 22(6), 631-40.

Computational and experimental studies on a flat plate are carried out to investigate flow characteristics with an array of three rectangular air jets impinging on its top surface. Pressure distribution on the impingement surface and flow visualization experiments with oil lamp black technique are carried out to qualitatively corroborate the computational flow structure with visualized patterns. Computations are carried out by shear stress transport (SST) k-ω turbulence model. The jet-to-plate spacing (H) to hydraulic diameter of slot (D) ratio (H/D) is varied from 0.5 to 4.0 and jet Reynolds number (Re) is varied from 5282 to 8450. The computationally obtained flow structure reveals the complex interaction of the wall jets. Primary pressure peaks are observed at the stagnation point and the secondary peaks are noticed at the interaction points of the wall jets. Position of the secondary peaks depends upon H/D and is independent of Reynolds number.

15 illus, 2 tables, 19 ref

015810   Saha M;Naskar M K;Chatterji B N (ECE Dep, Siliguri Institute of Technology, Siliguri, WB 734 009) : Soft, hard and block thresholding techniques for denoising mammogram images. IETE J Res 2015, 61(2), 186-9.

Mammogram is an easy and affordable means of diagnosis of breast cancer. Like other medical data, it is also affected by noise during acquisition. Therefore, it is a challenge for the researchers to denoise the mammograms for clear data extraction. This paper aims at denoising the mammogram by the wavelet and the curvelet transform with a motive to investigate the role of the "embedded" thresholding algorithm. As the thresholding technique is a key factor for the noise reduction, a comprehensive study on the employment of the different types of the thresholding techniques with the transforms have been presented methodically. A standard mammogram from the Mammographic Image Analysis Society database is supplemented with different types of noise and then denoised by the wavelet and the curvelet transforms using the three commonly used thresholding techniques to compare the denoising performance of the thresholding algorithms along with the transforms. This investigation renders a clear insight to the selection of the thresholding technique while denoising the mammogram with the transform.

4 illus, 1 table, 21 ref

015809   Rama Krishna D;Pandharipande V M;Koul S K (ECE Dep, Osmania Univ, Hyderabad-500 007) : Design of dual-band reconfigurable substrate integrated waveguide cavity-backed slot antenna array. IETE J Res 2015, 61(2), 121-31.

In this paper, a dual-band reconfigurable substrate-integrated waveguide (SIW) cavity-backed slot antenna 1 x 8 linear array is presented with dual states. The proposed SIW antenna array combines the features of the conventional metalized cavity-backed patch arrays such as surface wave suppression, high efficiency with low-manufacturing cost. The basic element has been designed, fabricated and the performance has been verified in the outdoor antenna test range. Here, PIN diodes have been used as a switching device to achieve the reconfigurability with dual-band operation. A corporate feed network has been designed and integrated with the antenna to make it as a linear array.

38 illus, 17 ref

015808   Rajiev R;Sadagopan P (Mechanical Engineering Dep, Bannari Amman Institute of Technology, Sathyamangalam-638 401) : Plastic deformation analysis of wear on insert component and die service life in hot forging process. Indian J Engng Mater Sci 2015, 22(6), 686-92.

One of the main critical problems in the hot forging process is the temperature rise in the die cavity and huge stresses generated during forging operation which leads to die failure due to wear, deformation of die, cracks etc. In this study, wear analysis is carried out in a die in local industry. The simulation of the forging process on the die and the work-piece is carried out by using commercially available software (DEFORM). The flow of the material in the die, die filling, contact pressure distribution, sliding velocities and temperature distribution of the die have been investigated. The depth of wear on the die surface is evaluated using the finite element simulation and then the total wear depth was determined. By comparing the numerical results with the measurement taken from the worn die, the wear coefficient is evaluated at different locations of the die surface and finally an average value of wear coefficient is suggested.

14 illus, 1 table, 17 ref

015807   Queyam A B;Pahuja S K;Singh D (NO, , ) : Labview-based virtual instrument for simulation of doppler blood flow velocimetry of umbilical artery. J Instrum Technol Innovation 2016, 6(1), 1-9.

Doppler blood flow velocimetry has become a routine practice for fetal surveillance in high-risk pregnancies. Doppler assessment of various fetal vascular beds helps in determining the relationship between fetal circulation and associated fetal conditions like hypoxia, brain-sparing effect and growth restriction. The umbilical artery, uterine artery and middle cerebral artery are three most studied vascular beds for fetal surveillance. In our research we are focused only on the umbilical artery since, abnormal umbilical artery velocimetric findings is a direct indication of an elevated value of resistance to the blood flow in the placenta. To better understand this relationship we have constructed a mathematical model of feto-placental circulation. A LabVIEW-based virtual instrument is also designed to simulate the model. The simulated waveform is similar to Doppler blood flow velocimetry of umbilical artery. Doppler indices (resistive index, systolic-to-diastolic ratio, pulsatility index) derived from simulated waveform revealed consistent relationship with advancing gestation as shown by real-time Doppler blood flow velocimetry of umbilical artery. Abnormal values of Doppler indices indicate complicated fetal conditions like intra-uterine growth restriction (IUGR).

015806   Qin Y;Gong Q;Wang A (College of physics and electronic Engineering, Nanyang Normal Univ, Nanyang 473061, People's Republic of China, Email: 641858757@qq.com) : Image encoding and watermarking in the double random phase encoding scheme with sparse representation strategy. J Optics 2015, 44(1), 45-52.

A novel method for image encoding and watermarking is proposed in this paper. It is shown that the security of the double random phase encoding (DRPE) scheme could be improved by watermarking the encoded image with a simple approach, which derives from the sparse representation strategy. The watermarked ciphertext is demonstrated to be stationary white noise, as a result of which the watermark hidden in the watermarked ciphertext is hard to be perceived. In addition, the watermark is also robust against noise and occlusion attacks. Both mathematical analysis and simulations are presented to illustrate the system performance.

8 illus

015805   Preet Kaur S;Sharma M (ECE Dep, Chandigarh Engineering College, Punjab Technical Univ, Landran, Mohali) : Radially optimized zone-divided energy-aware wireless sensor networks (WSN) protocol using BA (Bat Algorithm). IETE J Res 2015, 61(2), 170-9.

Problems of hot spot and energy consumption of nodes in wireless sensor networks (WSNs) have been tackled by the adoption of hybrid energy efficient distributed (HEED) and unequal clustering algorithm to prolong the network lifetime (UCAPN) protocols. These have involved the implementation of unequally sized clusters that are based on the distance of cluster head (CH) from the base station (BS). The BS partitions the network area into several radially divided zones depending on the distance from centre of the field and CHs are independently selected in each zone. Clustering, on the other hand, controls how data are transmitted and allows for aggregation in the clusters. However, whereas these topologies have been able to improve network life time, the problem of network void still persists. To address this, a radially optimized zone-divided energy-aware WSN protocol using bat algorithm is proposed. This protocol considers not only the distance from the BS, but also the angle at which the WSN develops. It gives a unique and equal opportunity for each sensor network to have ambience area for communicating and sensing necessary for its routing operations. Besides, it divides the sensing area into radial zones and employs the unequal clustering method in these zones to resolve the hot-spot problem. Based on the merits of zone-divided networks, CHs with great residual energy present in the high-energy regions are selected as the relay node in the inter-cluster multi-hop routing stage. Simulation results show that the proposed technique outperforms both HEED and UCAPN protocols. Bat algorithm is capable of predicting most critical nodes and generates a scalable and feasible energy-efficient routing technique for radially optimized zone-divided energy-aware WSN. By exploiting the angle at which the WSN develops, this protocol avails equal opportunity for each sensor network to have enough fields for communicating and sensing necessary for its routing operations. Using bat algorithm not only gives a superior packet delivery ratio, hence reducing voids, but also saves on energy consumption at the nodes. Sensor nodes are grouped into clusters to improve network performance.

7 illus, 1 table, 21 ref

015804   Parekh C;Kotwal C;Upadhyay H (NO, , ) : Review on transformer design and innovative aspects of optimization. J Instrum Technol Innovation 2016, 6(1), 10-22.

Transformer is the most costly and important component of power system. It is more than 100 years old technology. Technology has not changed drastically but the challenges are continuous increase in size and rating, competition in global market, accurate prediction of performance parameters, updating of design baseline and many more. Transformer design optimization (TDO) is a complex task in which designer have to ensure that the imposed specifications are met, while keeping manufacturing costs low. The research associated with design optimization is therefore more restricted involving different mathematical optimization methods. This paper presents review of research and development in transformer engineering and design optimization for the past 40 years based on more than 100 published papers, latest 10 transformer books and various national and international standards.

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015803   Pai P S;D'Mello G (Mechanical Engineering Dep, NMAM Institute of Technology, Nitte-574 110, Email: srinivasapai@rediffmail.com) : Vibration signal analysis for monitoring tool weat in high speed turning of Ti-6A1-4V. Indian J Engng Mater Sci 2015, 22(6), 652-60.

Vibration signals from metal cutting processes have been investigated for various purposes, including in-process tool wear monitoring. High speed machining is a machining process, where the speeds are at least 2-50 times greater than conventional machining. Titanium based alloys are difficult-to-machine materials which are widely used in various applications. Tool wear is a major problem in these materials because of their lower thermal conductivity and high hardness. In this context, this paper studies vibration signals acquired during high speed turning of Ti-6Al-4V, which is a widely used titanium based alloy for evaluating tool wear, mainly flank wear. Two types of inserts have been considered in the investigation namely an uncoated and a coated carbide insert. The experiments have been conducted with coolant and without coolant. The vibration signals have been subjected to wavelet transform (WT). The average energy of wavelet coefficients calculated from the vibration signals can be employed to monitor the tool wear in both the types of inserts investigated.

11 illus, 16 ref

015802   Onah C I;Mbamara U S;Totty A P (NO, , ) : Design and construction of water tank monitoring and control system with digital display. J Instrum Technol Innovation 2016, 6(1), 23-42.

Design and construction of water tank monitor and control system with digital display is designed to monitor the level of water in a tank. It displays the level of water at every calibrated level. The pump is activated automatically to refill the tank when the water level is low, when the tank is filled to its maximum capacity; the pump is automatically de-energized via the help of the probe that sends signal to the microcontroller, which in turn sends signals to the relay to switch OFF the pump machine. Several circuits put together to ensure proper working of this design, and the block diagram includes the supply unit, the voltage regulator, the microcontroller unit, the sensor unit, the display unit and the pump drives unit. The power unit is responsible for turning on the entire circuit. Some components are used to set up power unit and they include; a 12 V step-down transformer, a bridge rectifier circuit, a filtering capacitor and a voltage regulator integrated circuit (IC). The PIC16F48A microcontroller controls/monitors virtually all the actions carried out in this design. The sensor unit is responsible for sensing the level of water and transfer the current position of water to the microcontroller. The display unit in the circuit, which uses the properties of a seven-segment digital display, is used to physically show the current level of water in the tank.

015801   Onah C I;Mbamara U S;Ebegbulem M M (NO, , ) : Design, construction and testing of a solar charged multi-USB power bank using lithium-ion batteries. J Instrum Technol Innovation 2016, 6(1), 61-76.

This work proposes the design of a solar-powered charger for low-power devices. The level of the charging current is controllable and any residue power is saved to a rechargeable 12-volt lithium-ion battery. The power source is the solar panel, which is connected to a power booster for faster charging of any USB device connected to it. Quick charging is 20% of the battery output current (almost 10,000 mA/h) so that the current is limited to 2000 mA. Normal charging is 10% of the cellular battery output current (almost 1,000 mA/h), so that the charging current is limited to 500 mA. The design uses only a few components, making the cost system minimal and highly portable. It was simulated on MultiSim Ver. 11 before being implemented practically to validate it. The results from the simulation and the experiment show the design's sufficient feasibility for practical implementation.

015800   Oh N J (Electronic Engineering Dep, Korea National Univ of Transportation, Chungju-si, Korea) : Ultra-Low phase noise CMOS VCO design technique for mobile applications. IETE Tech Rev 2015, 32(1), 52-60.

This paper describes an ultra-low phase noise complementary metal-oxide semiconductor (CMOS) voltage-controlled oscillator (VCO) design technique targeted for GSM 900 and DCS 1800 base station (BTS) receiver, which require the toughest phase noise performance between 600 kHz and 3 MHz offset frequency. The proposed VCO suppresses the phase noise by three mechanisms; removes the current source, the main noise contributor in the VCO; includes double tuned resonators to prevent the switching pair from entering the triode region; filters out the second harmonic noise with a small size inductor at the common mode node of the VCO. The feasibility of the proposed VCO is verified using a 65 nm CMOS technology. Operating at around 3.6 GHz frequency range, the VCO is designed to meet the phase noise requirement of micro BTS and normal BTS. The proposed VCO consumes 27 mW dc power from a 0.7 V supply, and achieves the best figure-of-merit of -201dBc/Hz at 3 MHz offset.

14 illus, 3 tables, 15 ref

015799   Nam-Jin O (Electronic Engineering Dep, Korea National Univ of Transportation, Chungju-si, Korea) : Single-Stage Low-Power RF receiver front-end: series resonator based LMV cell. IETE Tech Rev 2015, 32(1), 61-9.

This paper proposes a novel low-power merged low noise amplifier (LNA), mixer, and voltage-controlled oscillator (VCO) called LMV cell exploiting a series LC (SLC) resonator. In contrast to the conventional parallel LC (PLC) resonator, the SLC resonator plays the role of enhancing the voltage swing at the series LC connection node which is cross coupled to the gate of the VCO switching transistors. The low intermediate frequency or baseband signal can be directly sensed at the drain nodes of the VCO switching transistors by adding simple resistor-capacitor (RC) filters. Using a 65-nm complementary metal-oxide semiconductor (CMOS) technology, the proposed LMV cell is optimized for the phase noise performance, and compared to the performance of the Liscidini's LMV cell which stacks the LNA, mixer, and VCO exploiting a PLC resonator. Compared to the Liscidini's LMV cell, the proposed LMV cell has larger voltage gain and better phase noise performance for the same dc power dissipation. While the simulated phase noise of the Liscidini's LMV cell is -47.8, -75.7, and -100.3 dBc/Hz, the phase noise of the proposed LMV cell is -71.2, -92.8, and -113 dBc/Hz at 10 kHz, 100 kHz, and 1 MHz offset frequency, respectively. The simulated voltage conversion gain of the Liscidini's LMV cell and the proposed LMV cell is 20 and 30 dB, respectively. Both LMV cells consume 0.35 mW dc power from a 1-V supply.

16 illus, 2 tables, 8 ref

015798   Naarayan S S;Dhayanidhi J;Nagarajappa B; Vorkady Y;Chandra S (Structural Technologies Div, National Aerospace Laboratories, Bangalore-560 017) : Behavior of organic gelatin/phenolic micro balloon composite under compressive loading, static and low velocity impact. Indian J Engng Mater Sci 2015, 22(6), 618-30.

Physical properties like density/porosity, stress-strain behavior and energy absorption of organic gelatin/phenolic micro balloon (PMB) composite is studied with respect to its water content and content of phenolic micro balloon. Quasi static compression tests and low velocity impact (LVI) tests are conducted on the gelatin/PMB composite samples with three different gelatin to water ratios (by weight) 1G:2W, 1G:3W and 1G:4W and four PMB contents 0%, 2.5%, 5% and 10% of the combined gelatin-water weight. The stress-strain behavior of the composite is studied through quasi-static compression tests at different loading rates. Low velocity impact tests are conducted to check the energy absorption of specimens and high speed videos of the impact tests were acquired to analyze the behavior of gelatin/PMB composite. The stress-strain tests show that the stiffness of the composite is dependent on both PMB and water content and that the behavior of composite is strain rate dependent or viscoelastic. The high speed imaging of the LVI tests conform with the energy absorption calculations that gelatin's energy absorption capability increases with increase in the water content as the lateral spread (and consequently the vertical compression of the composite samples) increases with water content. Further the stiffness of the composite increases with the increase of PMB content and reduction of water content. It is also found that 1G:4W composite with 0% PMB content absorbs the maximum energy and hence is ideal for energy absorption purpose.

10 illus, 4 tables, 24 ref

015797   Musavizadeh S M;Soroosh M;Mehidizadeh F (Faculty of Engineering, Shahid Chamran Univ of Ahvaz, Ahvaz, Iran, Email: m.soroosh@scu.ac.ir) : Optical filter based on photonic crystal. Indian J pure appl Phys 2015, 53(11), 736-9.

In the present paper, a novel structure for designing all optical filter based on photonic crystal structure is proposed. The filter is capable of selecting optical signals at wavelength of 1550 nm and the total footprint is less than 118 mm^{2. The transmission efficiency and bandwidth were obtained as 92% and 0.9 nm, respectively. After designing the filter, the impact of different parameters on the filtering behaviour of the structure has been studied. Simplicity of design and ultra-compact dimensions is the most significant characteristics of the filter.}

7 illus, 3 tables, 16 ref

015796   Mukhopadhyay M (NO, , Managing Director, Normet India) : Innovative mateials and methods for ground support, consolidation and water sealing for the mining industry. Wat Energy int 2015, 58(9), 67-9.

015795   Manoj M;Verma A (Civil Engineering Dep, Indian Institute of Science, Bengaluru-560 012, Email: ashishv@civil.iisc.ernet.in) : Design and administration of activity-travel diaries: a case study from Bengaluru city in India. Curr Sci 2015, 109(7), 1264-72.

Studies on travel survey instrument design and administration in the context of Indian cities are limited despite the fact that these aspects of travel survey face unique challenges here when compared to the cities in the developed world. Here we report results of a pilot survey conducted for evaluating the performances, alternative diary formats and survey administration techniques in Bengaluru city, India. The study proposes two diary formats. 'Diary-1' is in day-planner format and is a variant of the one reported earlier in the literature. 'Diary-2' is derived as a combination of 'Diary-1' and the trip-based diaries widely applied in Indian cities. 'Face-to-face', and 'drop-off and pick-up' methods of survey administration are considered for retrieving the activity travel information of individuals. Evidence appears to be strong that diary-2 is preferable to diary-1 for collecting the travel details of individuals. The comparison of the retrieval methods suggests that the face-toface method of instrument administration is superior to the drop-off and pick-up method in terms of higher response rates and minimum recording errors.

7 tables, 6 ref

015794   Madan M M (NO, , Former Executive Director, NHPC Ltd) : Tunnelling through extremely weak zone by adopting new methodology and materials. Wat Energy int 2015, 58(9), 59-66.

During tunnel execution encountering of thrust zones, shear zones, fracture zones, fluvioglacial material, sandy, silty or clayey strata, overburden material is very common. This type of strata makes tunnelling extremely challenging. Over and above encountering of seepage water creates flowing ground conditions and makes worst tunnelling conditions for excavation of underground structures. Tunnelling becomes very difficult and slow. By adopting new methods like Ground Freezing, Pre Grouting of Face with New Materials, Fibre Shotcreting with new materials and roof protection the weak strata can be strengthened inherently. The Paper deals with various new methods and new materials for controlling the weak zones and successful tunnelling.

8 illus

015793   Li X;Wan Y;Hu T;Yu P;Yu H;Yang J;Jiang X (Information Science and Electronics Engineering Dep, Zhejiang Univ, Hangzhou 310027, China, Email: iseejxq@zju.edu.cn) : Tunable silicon ring reflector. J Optics 2015, 44(1), 26-9.

Propose and experimentally demonstrated a thermally tunable ring reflector, which is made up of a Y-branch splitter and ring resonator on SOI platform using a CMOS-photonics technology. The results show good reflectivity which can up to be 90% near the 1550 nm. The reflective response is successfully tuned by one free spectral range through thermo-optic effect with a tuning efficiency of 5.3 mW/nm. We also discuss its applications in silicon hybrid lasers.

6 illus, 13 ref

015792   Kyeong-Ri K;Seung-Hoon C;Bae S B;Choi J S;Pan S B (Control Instrumentation Engineering Dep, Chosun Univ, Gwangju, Korea) : Four-joint based motion capture for spinal disease prevention system. IETE Tech Rev 2015, 32(1), 37-45.

Bad posture triggers spinal diseases by forming a twisted or crooked body. Therefore, it is vital for modern people mostly living a sedentary lifestyle to have correct posture. Thanks to rising demand in the health care sector and advancement of information technology these days, the development of a self-coaching system is underway using motion capture technology. With the self-coaching system applied to rehabilitation exercises or the sports field, subjects using the system can practice and learn rehabilitation exercises or sports motions on their own without any help. It is necessary to acquire and analyze motion data both from experts for coaching purposes and users who are being coached in order to develop the self-coaching system. The existing motion capture system has a drawback in that it is difficult to make smooth and natural motions because it uses heavy machines or a wired system. In this paper, we proposed a reasonably priced motion capture system requiring less preparation time and measurement space by using small-sized and lightweight microelectromechanical systems-based wireless inertial sensors to address the problems with the existing motion capture system. The analysis results show that the motion data of four joints acquired through the embodied system can be applied to the self-coaching system, and users can employ the system for spinal disease diagnosis themselves.

9 illus, 5 tables, 17 ref

015791   Kini M V;Murlikrishna T;Tupe P;Sankpal V;Umak K (NO, , The Tata Power Limited) : Learnings from power transformer failures in tata power. Wat Energy int 2015, 58(9), 36-40.

In the recent past, failures of few new as well as old Power Transformers have been experienced in Tata Power System. In view of substantial increase in failure of Power Transformers, detailed study of these failures were carried out along with system studies, operation and maintenance practices, design review etc. to obtain sustainable solutions to minimize transformer failures, which will lead to reliable & safe power supply to customers. This paper presents findings from the detailed study and recommendations to minimize recurrence of power transformer failures. Some of the technical cum administrative approaches are also discussed enabling Asset Manager to derive necessary justifications for life cycle management of Power Transformers (Design, Operation & Maintenance, Renovation and Modernization - repairs, overhauls, rewinding and replacement strategy).

3 illus, 6 ref

015790   Khadatkar A;Gite L P;Gupta V K (NO, Central Institute of Agricultural Engineering, Bhopal-462 038) : Interventions to reduce drudgery of workers in the traditional method of harvesting makhana (Euryale ferox salisb.) seeds from ponds. Curr Sci 2015, 109(7), 1332-7.

Makhana (Euryale ferox salisb.) is a seed produced from an aquatic crop, which normally grows in water bodies like ponds. In the traditional way of harvesting, a worker goes deep into the pond, lies down, holds his breath and drags the mud with both hands towards a bamboo pole called 'kaara', which is later sieved using a bamboo screen called 'ganjaa'. During this operation mud enters into the ears, eyes, nose and mouth of the worker. Also, the workers are affected by skinrelated diseases due to unhygienic working environment. Therefore, an intervention was made and an improved system was developed which consists of a floating platform providing support to a 10 l cylinder having compressed air, 10 m hose pipe with regulator and a mini diving kit having suit with cap, mask and content guage. A comparative study was conducted using both traditional system (T1) as well as improved system (T2) of harvesting Makhana seeds from ponds. The results indicate that the average output is only 3.8 kg/h with T1 system, whereas it is 11.3 kg/h with T2 system. The overall discomfort rate is 8.3 in case of T1 system, whereas it is 4.2 in case of T2 system. Also, the body parts discomfort score is higher (78.8) with T1 system compared to T2 system (48.2). The harvesting of Makhana seeds using the improved system involves less drudgery in comparison to traditional system with significantly higher work output.

3 illus, 5 tables, 6 ref

015789   Kaplonek W (Subject Group of Metrology and Quality, Production Engineering Dep, Faculty of Mechanical Engineering, Koszalin Univ of Technology, Raclawicka 15-17, 75-620 Koszalin, Poland, Email: wojciech.kaplonek@tu.koszalin.pl) : Conceptions of optical systems for multi-parametric in-process inspection of the surface texture and dimension. J Optics 2015, 44(1), 77-84.

A wide range of measurement procedures used in the modern production industry are expected to guarantee the acquisition of high-quality dimensional-shape repeatability, along with their proper utility and operating parameters. These procedures are carried out within the framework of in-process inspection by various types of optical measurement systems that use visible and IR laser radiation, as well as operating in automatic mode. One of the important issues related to in-process inspection, that has not found a satisfying solution yet, is the lack of an effective measurement system, that would allow for assessment of multiple parameters simultaneously, in real time. This work presents a proposal to solve this problem, which is focused on the analysis of ideological solutions in the form of optical measurement systems designed for multi-parametric in-process inspection of the surface texture and dimension. A number of such systems, which differ in configuration of optical paths and the number and type of applied optic and optoelectronic elements, among other things, were presented and discussed in detail. Moreover, a comparison of these systems in relation to their metrological properties was made and the advantages and disadvantages of particular solutions were analyzed. On the basis of the above mentioned data, the system with the most beneficial metrological properties was selected. It formed the basis for the development project of a small-sized optical measurement head, which was prepared in CAD/CAM/CAE SolidWorks 2012 Professional software by SolidWorks Corp.

5 illus, 1 table, 20 ref

015788   Journai A (NO, Universite de Technologie de Compiegne, Laboratoire Toverval, UMR 7337, Centre de Recherches de Royallieu BP20259-60205 COMPIENE cedex, France) : Numerical simulations of the surface topography effect on the generated frictional heat distribution in brake systems. Indian J Engng Mater Sci 2015, 22(6), 611-17.

Several studies have investigated the influence of various parameters on temperature at the surface contact disc/pad car, such as the vehicle deceleration, vehicle weight, braking force, coefficient of friction and pressure distribution over the braking surface area. However, hardly any study has been reported on the effect of surface roughness on the temperature distribution. In this study, a 3D numerical model is developed in order to investigate the effect of surface roughness on temperature field at different sliding speeds. The simulation reveals that the temperature at the surface and along the disc thickness depends strongly on asperities interactions and mode of surface deformation. This investigation also shows the beneficial role of copper in brake pad. The generated frictional heat at the contact surface between the brake disc and pad decreases with increasing of amount of copper up to a percentage of 8%. Beyond this proportion, the temperatures reach a stable level.

5 illus, 1 table, 24 ref

015787   Joshua O P (NO, TELK, Angamally) : Improving the preparation of power transformer technical specification. Wat Energy int 2015, 58(9), 31-5.

015786   Jafari M;Kamalvand M;Keshavarz M H;Zamani A; Fazeli H (Chemistry Dep, Faculty of Science, Yazd Univ, Yazd P.O.Box 89195/741, Islamic Republic of Iran, Email: mhkeshvaraz@mut.ac.ir) : Simple approach for prediction of the volume of explosion gases of energetic compounds. Indian J Engng Mater Sci 2015, 22(6), 701-6.

A reliable novel method is introduced for prediction of the volume of explosion gases (V_{Exp Gas}) of energetic compounds containing nitroaromatic, acyclic and cyclic nitramine, nitrate ester and nitroaliphatic compounds. It is based on the ratios of carbon and hydrogen atoms to oxygen atoms as well as the correcting function for decreasing overestimated value of V_{Exp Gas}. The reliability of the new method is tested and compared with outputs of complex detonation performance and thermochemical computer codes, which require the experimental values of the condensed phase heats of formation of energetic compounds. For 69 different types of energetic compounds, where the measured data are available, statistical parameters of the new model are good as compared to the predicted results of computer codes.

3 tables, 35 ref

015785   Islam S;Chong U (Electrical and Computer Engineering Dep, Ulsan Univ, Ulsan, South Korea) : Improvement in moving target detection based on houh transform and wavelet. IETE Tech Rev 2015, 32(1), 46-51.

Most fundamental problem in radar signal is the detection of a moving object or a physical phenomenon. This problem became more challenging to the signal processing and radar communities under severe interference. In order to effectively detect moving targets in strong noise conditions, we proposed a new method based on wavelet and Hough transform for multiple moving targets detection. First, the noise is removed from the received signal by the wavelet technique. We propose an improved wavelet threshold function. The new threshold function not only reduces constant error of soft thresholding but also improves the discontinuity of hard thresholding. Second, the image processing technique of the Hough transform is used. The benefits of this method include improved performance of detection and implementation flexibility, which indicates the effectiveness and robustness of the algorithm.

8 illus, 31 ref

015784   Hu H J;Wang H;Li Y Y;Yang M B;Ou Z (College of Material Science and Engineering, Chongqing Univ of Technology, Chongqing-400 050, China, Email: 48516686@qq.com) : Effective strains caused by different process conditions of extrusion-shear and its influences on the microstructures of AZ31 magnesium alloy. Indian J Engng Mater Sci 2015, 22(6), 661-8.

To improve strengths and microstructures evolution for magnesium alloy, extrusion-shear (ES) has been widely investigated because of its potentiality to produce ultra-fine grained microstructures of magnesium alloys. It is crucial to explore the effects of process parameters especially extrusion speeds and extrusion ratios on the deformation behaviors of magnesium alloy during ES process. Three-dimensional (3D) geometric models of ES processes with different extrusion speeds and extrusion ratios have been applied. Different extrusion speeds have been regarded as the initial conditions used in DEFORM^{TM-3D software, and different extrusion ratios have been taken. The microstructures evolvements have been analyzed by the simulation and experimental results. The strains in the extruded rods have been predicted during ES process. ES process with different extrusion speeds and extrusion ratios have been applied to fabricate AZ31 magnesium alloy rod with preheated temperature 400°C. The strains of ES process slightly increase with the rise of extrusion speeds. Average grain sizes prepared by lower extrusion speeds are bigger than those prepared by higher speeds with the same die structures. The strains slightly decrease with the rise of extrusion ratios. The average sizes of microstructures for magnesium alloy prepared by ES extrusion decrease with the rise of extrusion ratios.}

7 illus, 21 ref

015783   Gupta M K;Sood P K (Mechanical Engineering Dep, National Institute of Technology, Hamirpur-177 005, Email: munishbb@gmail.com) : Optimization of machining parameters for turning AISI 4340 steel using taguchi based grey relational analysis. Indian J Engng Mater Sci 2015, 22(6), 479-85.

In metal cutting, the choice of cooling method influences the deformation mechanism, which is related to the cutting forces, tool wear and surface finish of the parts. The deformation mechanism of AISI 4340 steels machining conditions is known to be very different from that of commonly used industrial materials. Therefore, the effect of cutting parameters and cooling methods on cutting forces, tool wear and surface roughness in machining of AISI 4340 steel is of particular interest. This paper investigates experimentally and analytically the influence of various process parameters, given as cutting speed (v), feed rate (f) and different cooling conditions (i.e. dry, wet and cryogenic in which liquid nitrogen used as a coolant) using uncoated tungsten carbide insert tool on three major characteristics (cutting force, tool wear and surface roughness) of a turned AISI 4340 steel part. The Taguchi's L9 orthogonal array, analysis of variance (ANOVA) and grey relational analysis (GRA) are executed to study the effects, significance, percentage contribution and optimum settings of given process parameters. The results obtained show that the machining performance can be improved by this approach.

3 illus, 5 tables, 23 ref

015782   Gopi Ram;Mandal D;Kar R;Ghoshal S P (Electronics and Communication Engineering Dep, National Institute of Technology, Durgapur) : CRPSOWM for linear antenna arrays with improved SLL and directivity. IETE J Res 2015, 61(2), 109-20.

In this paper, swarm-based algorithms craziness particle swarm optimization with wavelet mutation (CRPSOWM) have been applied for the optimal design of hyper beamforming of linear antenna array. The conventional gradient based optimization techniques are not efficient and get trapped on local optima for such multimodal highly non-linear constrained hyper beamforming optimization problem. Thus, the above evolutionary technique has been adopted. CRPSOWM incorporates a new definition of swarm updating with the help of wavelet theory. Wavelet mutation enhances the CRPSO to explore the solution space more effectively compared to the other optimization methods as reported in firefly algorithm (FFA). Thus CRPSOWM is apparently free from getting trapped at local optima and premature convergence. The simulation results show CRPSOWM outperforms FFA by achieving much greater reduction in side lobe level, improved directivity and much more improved first null beam width keeping the same value of hyper beam exponent. The optimized hyper beam is achieved by optimization of current excitation weights and uniform inter-element spacing. The approach is illustrated through 10-, 14-, and 20-element linear antenna arrays.

12 illus, 5 tables, 26 ref

015781   Goel R K (NO, CSIR-CIMFR Regional Centre, Roorkee, India) : Use of underground space for the development of cities in India. Wat Energy int 2015, 58(9), 41-5.

Urban living in metropolitan cities of India is becoming difficult day by day. It is difficult because the growth of population in cities is at a faster pace than the development of the cities. To cope up with similar situation underground or sub-surface facilities have been created in developed countries. It has vast potential in India also. In addition to providing the additional space, the advantage of underground space lies in the natural protection it offers to whatever is placed underground. Development of underground space in cities means efficient use of available underground space to develop infrastructural facilities underneath the city in order to avoid surface congestion and environmental conflicts. In the context of Smart City program of Government of India, it is high time now to include the use of underground space in the planning and development of cities.

2 illus, 1 table, 7 ref

015780   Fisher J;Hoole P R P;Pirapaharan K;Hoole S R H (Electrical and Communications Engineering Dep, The Papua New Guinea Univ of Technology, Lae, Papua New Guinea) : Applying a 3D dipole model for lightning electrodynamics of low-flying aircraft. IETE J Res 2015, 61(2), 91-7.

In this paper we apply a detailed electrostatic model of an aircraft to be used in an experimentally validated, new electric-charge-based circuit model for studying aircraft-lightning electrodynamics. The model is used to evaluate the electrodynamics of an aircraft under a thundercloud. As commercial and military aircraft continue to be subject to direct lightning flashes, we have previously developed a dipole model to characterize electrical currents and electric potential fluctuations on an aircraft for alternative design strategies to minimizing the severity of lightning-aircraft dynamics. With the increased severity of thunderstorms due to global warming, the need to predict and quantify electrical characteristics of the lightning-aircraft electrodynamics is greater, but they are normally not measurable. That dipole model is used here in a new a simple matrix formulation and applied to low-flying aircraft to compute the lightning channel voltages and currents after the aircraft is struck by lightning.

7 illus, 1 table, 25 ref

015779   Diallo A; (UNESCO-UNISA Africa Chair in Nanosciences-Nanotechnology, College of Graduate Studies, South Africa Univ, Muckleneuk ridge, PO Box 392, Pretoria, South Africa) : Effect of substrate temperature on the structure and the metal insulator transition in pulsed laser deposed VO₂ films on soda lime glass. J Optics 2015, 44(1), 36-44.

In this paper, we report the effect of soda lime substrate deposition temperature (T_s) on the crystal structure and the metal insulator transition of VO₂ thin films. Samples were deposited at substrate deposition temperature ranging from 450 to 600 °C by pulsed-laser deposition and characterized by x-ray diffraction and UV-VIS spectrophotometer. At a substrate temperature of 550 °C, the VO₂ (100) reflection dominate the spectrum showing a change in crystalline grains orientation. The highest transition temperatures of 74 °C with the lowest hysteresis width of 11 °C were obtained on the same sample grown at a substrate deposition temperature of 500 °C and also corresponding to the largest grains size of a value of 350 nm.

4 illus, 1 table, 25 ref

015778   Daranian M;Mohseni-Bonab S M; Mohammadi-Ivatloo B (Electrical Engineering Dep, Zanjan Univ, Zanjan, Iran) : Improvement of power system stability by optimal SVC controller design using shuffled frog-leaping algorithm. IETE J Res 2015, 61(2), 160-9.

There have been a variety of studies developed to design static var compensator (SVC) to enhance damping of electromechanical oscillations in power systems. This paper presents a novel method towards an optimal designing of SVC damping controller using shuffled frog-leaping algorithm (SFLA). The optimal parameters of the SVC controller are obtained using SFLA considering different loading conditions. A time-domain objective function is minimized using SFLA to find the optimum controller parameters. The proposed algorithm is implemented on a test system with different loading conditions. The damping characteristics of the presented technique are compared with genetic algorithm (GA) and bacteria foraging optimization algorithm (BFOA) in tuning SVC controller. The comparative analysis demonstrates the superiority of the proposed method on a wide range of operating conditions.

14 illus, 4 tables, 33 ref

015777   Chatterjee S;Pavan Kumar Y (NO, Raja Ramanna Centre for Advanced Technology, Indore-452 013, Email: schat@rrcat.gov.in) : Interferometric-auto-collimation technique for the determination of small angular tilt of a plane mirror. J Optics 2015, 44(1), 68-76.

A new common path interferometric auto-collimation technique is proposed. A laser autocollimator is combined with a modified triangular path interferometer for generating Fizeau fringes formed due to interference between two split up plane wave components with angular separation equal to four times of the angular deflection of the plane test mirror. The angular deflection of the plane test mirror is measured either from the fringe spacing or more accurately, from the slope of the optical path difference variation of the interference field obtained by applying polarization phase shifting interferometry. Results for a validation experiment are presented.

9 illus, 15 ref

015776   Chan H Y;Abdullah A B;Samad Z (School of Mechanical Engineering, Univ Sains Malaysia, 14300 Nibong Tebal, Palau Pinang, Malaysia, Email: mebaha@usm.my) : Precision punching of hole on composite panels. Indian J Engng Mater Sci 2015, 22(6), 641-51.

This study aims to investigate the effect of die clearance on the punched hole quality of composite panels. In practice, industries produce holes on composite panels by drilling. However, this process is time consuming, which lowers productivity. The process may improve by implementing punching instead. In this study, few die sets with different die clearances are fabricated, and an experiment is performed using a Universal Testing Machine (UTM). The images of the punched holes are scanned using a high-resolution machine vision camera, and then the holes are analyzed using the KLONK image measurement software. Results show that a smaller die clearance increases the accuracy of the punched hole size, and the effect of two-step punching on the quality of the punched hole sizes are also depicted.

16 illus, 8 tables, 16 ref

015775   Bhattacharya R;Basu A;Koul S K (Centre for Applied Research in Electronics, Indian Institute of Technology, Delhi-110 016) : Systematic determination of limits on noise figure and distortion in power constrained capacitive desensitized CMOS LNAs. IETE J Res 2015, 61(2), 192-8.

Systematic and generic approach is proposed to determine the minimum noise figure (NF), minimum second- and third-order harmonic distortion (HD₂, HD₃), and maximum input third-order intercept point (IIP3), achievable in a class of power constrained common source inductively degenerated low noise amplifiers (LNAs) using capacitance desensitization with and without multiple gated transistors. This is verified in complementary metal oxide semiconductor (CMOS) 180 nm technology. A Volterra series method is adopted to obtain closed-form expressions for both second- and third-order non-linearity. For validation, this analysis is applied to a highly linear single band LNA at 1.8 GHz and a linear dual band LNA at 2.8/3.4 GHz and corresponding limits on IIP3 and NF are established. To the best of the authors' knowledge for the first time, such quantitative limits for obtaining a simpler design trade-off have been presented to the LNA design community.

10 illus, 10 ref

015774   Augustine A K;Mathew S;Girijavallabhan C P; Radhakrishnan P;Nampoori V P N;Kailasnath M (International school of photonics, Cochin Univ of Science and Technology, Kochi 682022, Email: srrosmin2009@gmail.com) : Size dependent variation of thermal diffusivity of CdSe nanoparticles based nanofluid using laser induced mode-matched thermal lens technique. J Optics 2015, 44(1), 85-91.

Authors report a facile one-pot method for the preparation of high-quality CdSe nanoparticles (NPs) in aqueous solution under an air atmosphere using reflux. CdSe nanoparticles with tunable optical absorption and highly luminescent emission spectra of the size 4.6 nm-5.1 nm samples are discussed. Dual beam mode-matched thermal lens technique has been employed to study the effect of heat diffusion in the size series of CdSe nanoparticles. It is found that thermal diffusivity of 0.63 x 10^{-3 cm2/s, decreases with the increase in size of the CdSe nanoparticles. This change in thermal diffusivity makes the material for novel thermal applications. Characterization of the nanoparticles have done with TEM, SEM and XRD.}

10 illus, 1 table, 26 ref