Modelling and performance analysis of four and eight element TCAS

This semi-annual report describes the work performed during the period September 1989 through March 1990. The first section presents a description of the effect of the engines of the Boeing 737-200 on the performance of a bottom mounted eight-element traffic alert and collision avoidance system (TCAS). The second section deals exclusively with a four element TCAS antenna. The model obtained to simulate the four element TCAS and new algorithms developed for studying its performance are described. The effect of location on its performance when mounted on top of a Boeing 737-200 operating at 1060 MHz is discussed. It was found that the four element TCAS generally does not perform as well as the eight element TCAS III

Electrochemical supercapacitors: energy storage beyond batteries

Recently, a new class of reversible electrochemical energy storage systems have been developed that use: (a) the capacitance associated with charging and discharging of the electrical doublelayer at the electrode-electrolyte interface and are hence called electrical double-layer capacitors (EDLCs), and (b) the pseudocapacitance with electrosorption or surface redox reactions which are referred as pseudocapacitors. While EDLCs with capacities of many tens of farads per gram of the electrode material have been achieved employing high surface-area carbon powders, fibres, or felts, much higher capacitance values are accomplished with pseudocapacitors employing certain high surface-area oxides or conducting polymers. These electrochemical capacitors are being envisaged for several applications to complement the storage batteries. This article provides a brief introduction to scientific fundamentals and technological applications of electrochemical supercapacitors. It is also stressed that there is a substantial scope for technology development in this newly emerging area, where materials science and polymer technology will have a pivotal role in conjunction with electrochemistry

Ferromagnetism in Fe-substituted spinel semiconductor ZnGa2_2O4_4

Motivated by the recent experimental observation of long range ferromagnetic order at a relatively high temperature of 200K in the Fe-doped ZnGa$_2$O$_4$ semiconducting spinel, we propose a possible mechanism for the observed ferromagnetism in this system. We show, supported by band structure calculations, how a model similar to the double exchange model can be written down for this system and calculate the ground state phase diagram for the two cases where Fe is doped either at the tetrahedral position or at the octahedral position. We find that in both cases such a model can account for a stable ferromagnetic phase in a wide range of parameter space. We also argue that in the limit of high Fe$^{2+}$ concentration at the tetrahedral positions a description in terms of a two band model is essential. The two $e_g$ orbitals and the hopping between them play a crucial role in stabilizing the ferromagnetic phase in this limit. The case when Fe is doped simultaneously at both the tetrahedral and the octahedral position is also discussed.Comment: 10 pages, 9 figures, added text, J. Phys. Cond. Mat. (to appear

Investigating the VLSI Characterization of Parallel Signed Multipliers for RNS Applications Using FPGAs

Signed multiplication is a complex arithmetic operation, which is reflected in its relatively high signal propagation delay, high power dissipation, and large area requirement. High reliability applications such as Cryptography, Residue Number System (RNS) and Digital Signal Processing (DSP)2019;s effective performance is mainly depend on its arithmetic circuit's performance. Trend of using Residue Number System (RNS) instead of Constrain over-whelming Binary representation is promising technique in VLSI Systems and Multiplier is the basic building block of such systems. In this paper we have considered signed Modified Baugh Wooley Multiplier and Modified Booth Encoding (MBE) Multiplier logic for analysis and synthesized on best suited application platform. Analysis has taken account of Delay, Number of Logic Element requirements; Number of Signal Transition for particular sample input and its Power Consumption were analyzed for both Modified Baugh Wooley Multiplier and Modified Booth Encoding Multiplier. Analysis of Multiplier is described in Verilog HDL and Simulated using two different simulators namely Xilinx ISIM and Altera Quartus II. Then for comparative study, both multipliers are synthesized with Xilinx Virtex 7 XCV2000T-2FLG1925 and Altera Cyclone II EP2C35F672C6 and same parameter as discussed above are also evaluated. Booth Recoding provides overall advent of 9.691% in terms of area and approximately 43 % in terms of Delay compared to Modified Baugh Wooley Multiplier implemented using FPGA Technology

Evaluation of antidiabetic activity of fruit of Coriandrum sativum. Linn methanolic extract in Streptozocin induced diabetic wistar Albino rats

Background: Diabetes prevalence is estimated to increase annually. Numerous people use traditional medicine, such as India also considered as the diabetic capital in the world. Diabetes is a metabolic disorder characterized by disturbances in lipid, carbohydrate and protein metabolism. The present study to evaluate the antidiabetic potential of coriandrum sativum. linn fruits methanolic extract in streptozocin induced diabetic wistar albino rats model.Methods: Diabetes induction in wistar albino rats by administration of streptozocin (50mg/kg, i.p.) in citrate buffer. 30 wistar albino rats were divided into 5 groups (A, B, C, D, E). Group A: served as normal control, whereas Group B: diabetic control, Group C, D methanolic coriandrum sativum Linn. fruits extract (CSFME) at a dose of 100, 200mg/kg orally, Group E was given standard drug Glibenclamide (0.5mg/kg) orally. All groups are administered for the period of 14 consecutive days and blood sugar levels was measured at regular intervals up to end of the study.Results: This present research study confirms that the test drug compound CSFME has sustained oral hypoglycaemic activity and statistically significant (p ≤0.05) and which is comparable with standard drug Glibenclamide.Conclusions: This research study confirms that the CSFME has antidiabetic activity against streptozocin induced wistar diabetic albino rats. It could be a novel antidiabetic agent and also a dietary adjunct in the type 2 diabetes management and its complication. Further studies are necessary required to confirm the antidiabetic activity of individual phytochemical compounds of Coriandrum sativum

Utilization of phosphorus for casein biosynthesis in the mammary gland. II. Incorporation of P<SUP>32</SUP> into free phosphopeptides of milk and of mammary gland

This article does not have an abstract

Physical characterization of cellulosic fibres from Sesbania grandiflora stem

437-441In the present investigation, the morphology and the porosity of the Sesbania grandiflora fibre has been studied by SEM in order to understand their effects on the capillary structure and the hygroscopic behavior. The physical properties, such as tensile strength, elongation, density, fineness, morphological structure, water absorption coefficient and thermo-gravimetric analysis, have been examined. X-ray diffraction and Fourier transform infrared spectroscopy (FTIR) are used to identify the crystalline index and chemical groups present in the fibre. It has been found that this new vegetable material has a very low bulk density and a highest water absorption capacity. FTIR and X-ray analyses have proved that these fibres are rich in cellulosic content with crystallinity index of 51% cellulose content of 70.75 wt %, density of 1.4738 g/cc, and tensile strength of 365-11100 Mpa. The results show that Sesbania grandiflora fibres have comparable fibre strength, elongation and cellulose content to jute, hemp, ramie, Phoenicx sp, okra and Prosopis juliflora. The new fibre has better crystallinity index than banana, bagasse and sponge gourd and hence can be utilized for technical textiles application

Physical characterization of cellulosic fibres from Sesbania grandiflora stem

In the present investigation, the morphology and the porosity of the Sesbania grandiflora fibre has been studied by SEMin order to understand their effects on the capillary structure and the hygroscopic behavior. The physical properties, such astensile strength, elongation, density, fineness, morphological structure, water absorption coefficient and thermo-gravimetricanalysis, have been examined. X-ray diffraction and Fourier transform infrared spectroscopy (FTIR) are used to identify thecrystalline index and chemical groups present in the fibre. It has been found that this new vegetable material has a very lowbulk density and a highest water absorption capacity. FTIR and X-ray analyses have proved that these fibres are rich incellulosic content with crystallinity index of 51% cellulose content of 70.75 wt %, density of 1.4738 g/cc, and tensilestrength of 365-11100 Mpa. The results show that Sesbania grandiflora fibres have comparable fibre strength, elongationand cellulose content to jute, hemp, ramie, Phoenicx sp, okra and Prosopis juliflora. The new fibre has better crystallinityindex than banana, bagasse and sponge gourd and hence can be utilized for technical textiles application

Performance of traffic-alert collision avoidance (TCAS) antennas in the presence of scatterers

The performance of two TCAS systems is studied in the presence of electromagnetic scatterers. TCAS is an aircraft mounted angle of arrival (AOA) system, which estimates the bearing of a signal transmitted from a mode-S transponder on another nearby aircraft (intruder). Two systems are studied: (1) Comparison of Relative Amplitude system (CRA), and (2) Spiral Phase Antenna (SPA). The CRA antenna receives the reply via four switched beams. The bearing is estimated by comparing the amplitudes of the received signal. The SPA is based on the phase interferometer, which utilizes the received phase via sum and difference beams. The AOA is computed by comparing the reply with similar values on a calibration table, which is generated by modeling the TCAS antenna on the bare fuselage of a Boeing 727-200. The antenna patterns for the TCAS are found via high frequency methods based on the Uniform Geometric theory of Diffraction (UTD). By minimizing the standard deviation of the bearing error in a specified angular sector, optimal locations for top and bottom mounted TCAS antennas are found on the Boeing 727-200, 737-300 and 747-200 airframes. It will be shown that the overall bearing errors of the amplitude system are consistently smaller than the spiral phase TCAS. The effect of two types of nearby scatterers--antennas, and engine inlets--is studied. The AT741 L-band blade, DMC60-1 VHF Communication antenna were chosen as being representative antenna interference examples. Models are derived for the blades via a moment method analysis followed by a least squares procedure to synthesize the scattering patterns. Studies were conducted to estimate the minimum separation between the two antennas for acceptable operation. It will be shown that the spiral phase TCAS is adversely affected by the presence of a blade antenna. The amplitude system does not suffer from this limitation, especially for the forward look angles which are of most interest here. A model to represent the inlet scattering is based on the multiple scattering method and UTD. The engine on top of the B727-200 fuselage is modeled by a terminated circular waveguide. Then, the effect of moving the antenna forward on the fuselage is studied. It is again shown that the performance of the amplitude system is superior

An Intelligent FPGA Based Anti-Sweating System for Bed Sore Prevention in a Clinical Environment

Bed sores, a common problem among immobile patients occur as a result of continuous sweating due to increase in skin to bed surface temperature in patients lying on same posture for prolonged period. If left untreated, the skin can break open and become infected. Currently adopted methods for bed sores prevention include: use of two hourly flip chat for repositioning patient or use of air fluidized beds. However, the setbacks of these preventive measures include either use of costly equipment or wastage of human resources. This paper introduces an intelligent low cost FPGA based anti-sweating system for bed sores prevention in a clinical environment. The developed system consists of bed surface implanted temperature sensors interfaced with an FPGA chip for sensing the temperature change in patient’s skin to bed surface. Based on the temperature change, the FPGA chip select the - mode (heater/cooler) and speed of the fan module. Furthermore, an alarm module was implemented to alert the nurse to reposition the patient only if patient’s skin to bed surface temperature exceeds a predefined threshold thereby saving human resources. By integrating the whole system into a single FPGA chip, we were able to build a low cost compact system without sacrificing processing power and flexibility