017517   Patel P B;Rane V S;Hamde S T;Chaudhari B S (NO, Dr. D.Y. Patil Institute of Engineering and Technology, Pune-411 018, Email: prashantbgpatel@rediffmail.com) : Characterization of the properties of an optical wave field : an investigation. J Envir Res Dev 2009, 4(2), 549-53.

The characterization of the various properties of an optical wave field is extremely important in the field of current fiber optics research. According to Maxwell's equations, wave fields contain the properties of both amplitude and phase and which is a function of space-time. In practice, it is possible to measure only the amplitude squared [intensity] of the wave field directly, using various means like, digital or other detectors, photographic film, or the human eye. But it is difficult to directly measure the phase1 of the wave field, as it is not possible to make detectors with a temporal bandwidth comparable to the oscillation of optical or quantum mechanical fields. The ability to reconstruct the phase of an optical wave field has many applications like in removing the effects of atmospheric turbulence in astronomy, in the imaging of materials in electron microscopy etc. The characterization of optical phase is also important in the bio-medical parameter measurement applications. Many different approaches have been developed to overcome the phase problem. Each one of these techniques has own advantages and disadvantages, which largely depend on the various system parameters. Ideally, researchers would like a technique for the reconstruction of phase information that provides phase structure directly using simple measurements. The novel method of phase retrieval based on the Transport of Intensity Equation (TIE), is one such technique, allowing us to recover both quantitative and qualitative phase information directly from intensity measurements. These proposed studies will highlight the background for TIE phase recovery, which will be helpful in Biotechnology and Biomedical Parameter Sensing areas.

^ssc3 illus, 6 ref

017516   Panna Lal Singh;Sarviya R M;Bhagoria J L (NO, Central Institute of Agricultural Engineering, Berasia Road, Bhopal-462 038, Email: plsingh@ciae.res.in) : Effect of some parameters on linear fresnel solar concentrating collectors. J Envir Res Dev 2009, 4(2), 528-34.

Solar concentrating systems are best suited for medium-grade (60-250°C) thermal applications. The absorber of the linear solar concentrating device play very important roll in collection of solar energy. The non-evacuated solar absorber painted with ordinary black paint yield poor performance. To achieve higher efficiency of the solar collector, there should be minimum thermal losses from the absorber. The overall heat loss coefficient of the absorber includes convection, radiation and conduction heat losses. Surface coating on the absorber surface, glass cover, shape and size of the absorber surface, temperature of the absorber etc. affects thermal performance of the absorber. Transparent glass cover at bottom allows light entry and at the same time reduced heat loss due to wind. Rise in oil temperature with increase in number of mirrors, but the increase was not found to be linear. The time required to reach peak temperature reduced proportionally with increase in number of mirrors.

3 illus, 1 table, 15 ref

017515   Pandey R K;Rehman A;Sarviya R M (Mechanical Engineering Dep, M.A. National Institute of Technology, Bhopal, Email: rkpmanit@gmail.com) : Environmental benefits through reduction in exhaust emissions of C.I. engine using clean burning fuel : an experimental study. J Envir Res Dev 2009, 4(2), 484-96.

Transport vehicles greatly pollute the environment through emissions such as CO, CO2, NOx, SOx, unburnt or partially burnt HC and particulate emissions. Fossil fuels are the chief contributors to urban air pollution and major source of green house gases and considered the prime cause behind the global climate change. With the increasing fuel prices, the auto industry forced to make their engines to breathe cleanly and fuel efficiently. This paper discusses about the utilization and advantages of using karanja oil, as the bio fuels. The experiments conducted on single cylinder direct injectfon diesel engine for The various blends (B20, B40, B60, B80 and B100) of karanja biodiesel with diesel and compared with the diesel fuel. The results indicate that Blends of karanja oil gives good performance of the engine in addition to the lower engine emissions. It has been observed from the results that by using Karanja biodiesel there is decrease in brake thermal efficiency and increase in specific fuel consumption, the reason for this the combined effects of the relative density, viscosity and heating value of the blends and poor combustion characteristics of Karanja biodiesel due to higher viscosity and poor volatility. The gaseous emissions of oxide of nitrogen from all blends are higher than mineral diesel at all engine loads. Significant improvements observed in the performance parameters of the engine as well as exhaust emissions, when blends of Karanja oil used. Karanja oil blends with diesel can replace diesel for operating the C.I. engines giving lower HC, CO, Smoke emissions and improved engine performance.

8 illus, 4 tables, 15 ref

017514   Pandey K M;Deb K;Kumar U (Mechanical Engineering Dep, N.I.T. Silchar, Assam) : Experimental studies on effect of noise level control for 7.5 KVA diesel generator set with an enclosure. J Envir Res Dev 2009, 4(2), 506-16.

The effects of noise level control for 7.5 KVA diesel generator set with and without enclosure is discussed. It has been found that the noise level at zero distance with enclosure is 78.6 dB and with the recorded data graphs have been plotted, it shows a noise of 27.4 dB(A) reduction. It is discussed in detail in this paper that constructing a double wall enclosure and if the air-gap is filled with mineral wool, it can give a further 10 dB reduction.

5 illus, 2 tables, 16 ref

017513   Pakdil M (Mechanical Engineering Dep, Abant Izzet Baysal Univ, 14280, Bolu, Turkey, Email: pakdilm@ibu.edu.tr) : Failure analysis of composite single bolted-joints subjected to bolt pretension. Indian J Engng Mater Sci 2009, 16(2), 79-85.

In this study, failure analysis of composite single bolted joints has been performed. To determine effects of joint geometry and stacking sequences of laminated composite plates on bearing strength and failure mode, experimental studies have been carried out by which edge distance-to-holc diameter ratio (H/D), and plate width-to-hole diameter ratio (W/D) are varied from 1 to 5 and 2 to 5, respectively. In addition, bolt pretensions of 0, 3 and 6 Nm are applied. The composite laminated plates are stacked with the following four different orientations: [070730°/30°]_s, [0°/0745745°]_s, [0°/0°/60°/60<14 4>]_s, and [0°/0°/90°/90<14 4>]_s. Experimental results show that failure mode and bearing strength are closely related to by stacking sequence of plates, geometrical parameters, and bold tension. An increase in bolt pretension positively affected failure behaviour of bolted joints.

4 illus, 8 tables, 16 ref

017512   Noorpoor A R;Aghsaee M;Hamedani A (Assistant Professor, Automotive Engineering Dep, Iran Univ of Science and Technology, Narmak, PO Box 16844, Tehran, Iran, Email: noorpoor@iust.ac.ir ) : Effects of HCCI combustion on performance of the heavy-duty diesel engine dueled with natural gas fuel. Int J theor appl mech 2008, 3(2-3), 133-48.

Homogeneous charge compression ignition (HCCI) is one of the alternatives to reduce significantly engine emissions for future regulations. This new alternative combustion process is mainly controlled by chemical kinetics in comparison with the conventional combustion in internal combustion engines. In this paper, a heavy duty diesel engine is modeled in the GT-Power engine simulation software. After calibration of model, the outputs of the simulated model were compared with the available experimental data. The comparison showed that the results of a simulated engine and experimental data were in good agreement. Then, the HCCI combustion of the considered engine with the natural-gas fuel was simulated by a variable volume computation including the piston motion into the chemical reaction design, CHEMKIN, package. The SENKIN code used in order to simulate the in-cylinder combustion. A single-zone zero-dimensional model was used in order to simulate the combustion phenomena. The chemical kinetic mechanism incorporated the GRI-3.0 mechanism that considers 53 species and 325 reactions together. Finally, these combustion results were transferred into an overall model of the considered engine in GT-Power software in order to calculate the engine performance characteristics. The computational model was validated by available experimental data. The results showed that the calculated data were relatively in good agreement with the experimental data. In contrast with the diesel engine, in HCCI combustion, the peak pressure is increased suddenly. The BMEP and output power in HCCI engine are also less than the BMEP and output power in diesel engine in the identical engine velocity. Also, the BSFC in HCCI engine is by far less than the diesel engine. The brake thermal efficiency in HCCI engine is a little less than the ones in diesel engine. The average amount of NO_X concentration in HCCI engine is by far less than the diesel engine.

16 illus, 1 table, 26 ref

017511   Nirmala Peter E C;Madhav M R;Saibaba Reddy E (Civil Engg., J.N.T.U. College of Engg., Kukatpally, Hyderabad-500 072, Email: ecnps@yahoo.co.uk) : One-domensional non-reactive contaminant transport with scale-dependent dispersion. Indian Geotech J 2009, 39(1), 64-80.

The classical convection-dispersion equation describing contaminant transport through porous media assumes a constant dispersion coefficient. However several field and laboratory studies indicated scale-dependent dispersion. Therefore this paper presents a study of the convection-dispersion equation (CDE) with a scale-dependent dispersion coefficient which varies as a power law function with distance of travel. The governing equation was solved numerically using the finite difference method and the solution is shown to be in good agreement with the experimental data of Huang et al. (1995) and also the data of the column test conducted in the laboratory.

15 illus, 4 tables, 14 ref

017510   Niranjan Kumar M S R;Sarcar M M M;Bala Krishna Murthy V (Production Engineering Dep, V R Siddhartha Engineering College, Vijayawada-520 007, Email: m_niranjankumar@rediffmail.com) : Static analysis of thick skew laminated composite plate with elliptical cutout. Indian J Engng Mater Sci 2009, 16(1), 37-43.

The behaviour of a laminated composite skew plate with elliptical hole subjected to transverse pressure loading has been investigated in the present analysis. A finite element method which works on the basis of three-dimensional theory of elasticity is employed to evaluate the transverse deflection, in-plane stresses and interlaminar stresses. The results obtained by varying the skew angle, size of the cutout and the effect of elliptical cutout orientation are discussed. The magnitudes of the transverse deflection and in-plane stresses for pressure loading arc observed to be less at higher skew angles and for larger size of the cutout. It is also observed that the configuration 3 of the ellipse (major axis of the ellipse parallel to inclined sides of the skew plate) is found to be better with respect to the major stresses point of view. The solutions of skew structures considered in the present analysis may be useful for the construction of safe and efficient structures like skew bridges and swept wings of aircraft structures.

16 illus, 1 table, 11 ref

017509   Nesaraj A S (Chemistry Dep, Karunya Univ, Coimbatore-641 114, Email: drsamson@karunya.edu) : Recent developments in solid oxide fuel cell technology. J scient ind Res 2010, 69(3), 169-76.

This review presents development of low temperature solid oxide fuel cells (SOFC), which with high efficiency and high environmental performance have shown excellent potential as a future source of energy for vehicles and homes. Gd₂O₃ and Sm₂O₃ doped ceria based nanomaterials were developed world wide, as alternate electrolyte materials for SOFCs working at reduced temperature (700°C) since, state-of- art YSZ based electrolytes undergo interfacial reactions with adjoining cell components at operating temperature of SOFC after prolonged operation. Novel ceramic composite materials are reported as alternate electrode components of reduced temperature SOFC. Iron based alloys are developed as current collectors for low temperature SOFC applications.

^iia2 illus, 2 tables, 61 ref

017508   Nema A;Khare V K;Khaira H K (Mechanical Engineering Dep, M.A.N.I.T., Bhopal-462 051, Email: archana.nema@gmail.com) : Power transmission substation location modeling : a socio-environmental and economic perspective. J Envir Res Dev 2009, 4(2), 535-44.

Various Studies reveal that undesirable effects of extra high voltage (EHV) to the surrounding population and environment. Substation location modeling research has emphasized on the proximity to demand points or population centers to minimize transmission losses. An attempt has been made to formulate a new multi goal cost model considering both quantitative and qualitative factors, to facilitate decision making for locating a new EHV substation in an existing power transmission network so as to minimize cost as well as its undesirable effects on the surrounding environment.

2 illus, 1 table, 20 ref

017507   Nandgaonkar A B;Deosarkar S B (Electronics and Telecommunication Engineering Dep, Dr. Babasaheb Ambedkar Technology Univ, Lonere-402 103) : Successful design of singly-fed wideband and high gain micro strip antenna. IETE J Res 2009, 55(6), 294-8.

A major disadvantage of the micro strip-patch antenna is its inherently narrow impedance bandwidth of only a couple of per cent. Intensive research is going on to develop bandwidth-enhancement techniques by keeping its size as small as possible. In this paper, square ring MSA with two nearly square slots is designed, simulated, fabricated and tested. It is a singly-fed, wideband and high gain micro strip Antenna. The proposed antenna is left-hand circularly polarized and operates in 5-6 GHz frequency band. The impedance bandwidth with an input VSWR of two is obtained as 16.23% while the 6dB axial ratio bandwidth is measured over 4.52%.

7 illus, 4 tables, 14 ref

017506   Murali Krishna M V S;Ramana Reddy C V; Seshagiri Rao V R (Mechanical Engineering Dep, Chaitanya Bharathi Institute of Technology, Gandipet, Hyderabad-500 075, Email: mvsmk_in@yahoo.com) : Control of nitrogen oxides in high grade low heat rejection disel engine by selective catalytic reduction technique. Asian J chem envir Res 2010, 3(1), 29-32.

The investigation attempts to reduce nitrogen oxides (NOx) emissions in the exhaust of low heat rejection diesel engine by selective catalytic reduction technique. The lanthanum ion exchanged zeolite (catalyst-A) and urea infused lanthanum ion exchanged zeolite (catalyst-B) are used as catalysts for reduction of NOx levels in both conventional (CE) engine and low heat rejection (LHR) engine which consists of an air gap insulated piston with superni (an alloy of nickel), air gap insulated liner with superni insert and ceramic coated cylinder head. The effect of temperature of catalyst, space velocity, and void ratio on the reduction of NOx in the exhaust of both engines are also studied.

6 illus, 1 table, 13 ref

017505   Mukund R;Mishra A K (Computer Science and Engineering Dep, Indian Institute of Technology, Guwahati-781 039) : Fast and modular analog rank order filter using CMOS technology. IETE J Res 2009, 55(5), 201-4.

Apply the sorting network theory to construct an analog rank order filter. Presents a voltage mode CMOS two-input sorting element and arrange these to form a rank order filter. The resulting circuit is simple and is a high-speed, high-precision design. Although the transistor count is moderately higher than other designs, the proposed circuit simultaneously outputs signals of all ranks rather than of just one specified rank. We also develop a slightly modified design which calculates the rank of a given signal. We present reports of simulations to verify the performance of the device.

8 illus, 9 ref

017504   Mittal S K;Manjeet Singh;Sardana H K;Dhingra S (NO, Central Scientific Instruments Organisation (CSIO, SCIR), Sec-30 C, Chandigarh-160 030, Email: skmskm1@rediffmail.com) : Instrumental monitoring of Mansa Devi landslide site and interpretation of data. Indian Geotech J 2009, 39(3), 317-27.

Landslides represent one of the natural hazards with major social and economic impact in the world. It is found that landslides are initiated by small movement of slopes and when combined with natural or man made factors over a period of time leads to larger magnitude landslide (it would have not been true if proper monitoring could have carried out since beginning). The Physics of landslide is usually very complex and its proper understanding requires lots of instrumentation and observations. Several monitoring techniques have been devised for the pre detection of the landslide to check the devastating effects and damages caused by them. Most important among them is Instrumental Monitoring of landslide, which enables us to evaluate the amount of displacement in different areas & then to understand landslide mechanism. In this paper authors have highlighted various Instrumentation schemes for landslide monitoring & early warning. Also an instrumentation scheme adopted for Mansa Devi (Handwar) landslide site is explained with interpretation of recorded data of a small area. This active landslide which started almost a decade ago, completely damaged 300m stretch of Haridwar bypass road and posing a serious threat to all the residential and commercial establishments located at the basement.

3 illus, 1 table, 20 ref

017503   Misic D;Stojkovic M;Domazet D;Trajanovic M; Manic M;Trifunovic M (Faculty of Mechanical Engineering, , Nis, A. Medvedeva 14, 18000 Nis, Serbia, Email: draganm@masfak.ni.ac.rs) : Exception detection in business process management systems. J scient ind Res 2010, 69(3), 188-93.

This study presents exception detection in process management system, which uses active semantic model (ASM), a hybrid system comprising semantic networks, expert systems, object oriented programming and fuzzy logic. ASM is employed to capture semantic features of all kinds of workflow situations, as well as to detect and interpret exceptions.

3 illus, 15 ref

017502   Mathur S;Gangwar R P S (Electronics & Communication Engineering Dep, College of Technology, G B Pant Univ of Agriculture & Technology, Pantnagar-263 145, Email: mathur_sanjay@rediffmail.com) : Decision directed smart antenna system with neural estimation for M-quadrature amplitude modulated signals. Indian J Radio Space Phys 2010, 39(1), 45-52.

Adaptive beamforming and direction of arrival (DOA) estimation are among the prime areas of research which draw the attention of research community to address the ever growing demand for increased capacity in mobile communication systems. Smart antennas, which are essentially adaptive array antennas coupled with intelligent signal processing have emerged as an important category of systems capable of providing solution to this problem. Neural networks are also being widely used for developing intelligent systems and influencing signal processing in communication systems. A decision directed approach is proposed for blind adaptation of smart antenna system using a complex neural estimation of parameters for beamforming. The paper presents a simulation study of the decision directed smart antenna system with neural estimation (DDSA-NE) for multi-quadrature amplitude modulated (M-QAM) signal environment with 4, 16, and 64 constellations. The results indicate the effectiveness of the proposed scheme.

8 illus, 1 table, 16 ref

017501   Marzuki A;Shakaff A Y M;Sauli Z (School of Electrical and Electronic Engineering, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang) : A 1.5 V, 0.85- 13.35 GHZ MMIC low noise amplifier design using optimization technique. IETE J Res 2009, 55(6), 309-14.

Describes how a broadband, 1.5 V, 0.85 -13.35 GHz low noise amplifier in 0.15 μm 85 GHz PHEMT process is synthesized to simultaneously meet multiple design specifications such as bandwidth, noise Figure, power gain and power consumption. Power-constrained synthesis technique is used to design the broadband amplifier. The simulated peak S21 is 19.8 dB, maximum noise Figure is 2.5 dB, 3-dB bandwidth is 12.5 GHz and power consumption is 73.5 mW. The calculated Figure of merit (FOM) is better than many reported broadband low noise amplifier (LNA).

12 illus, 3 tables, 12 ref

017500   Mao L F (School of Electronics and Information Engineering, Soochow Univ, 178 Gan-Jiang East Road, Suzhou-215 021) : Effect of dielectric constant mismatch on capacitance-voltage curve. IETE J Res 2009, 55(5), 218-21.

This paper investigates the effects of a dielectric-constant mismatch between gate dielectric and silicon substrate on the capacitance-voltage curve of high-K MOS structures, numerically, via fully self-consistent solutions of Schrodinger and Poisson equations. Results demonstrate that the capacitance-voltage curve of a high-K MOS structure compared to that of SiO<>2 MOS structure with the same equivalent oxide thickness shifts to lower gate voltage with increasing dielectric constant of the gate dielectric, thickness of gate dielectric, and acceptor density in silicon substrate. The results also demonstrate that a higher dielectric thickness, thicker gate dielectric, and higher acceptor density for a high-K MOS structure lead to a larger increase in capacitance compared to SiO₂ MOS structure with the same equivalent oxide thickness.

3 illus, 12 ref

017499   Mageswari M;Vidivelli B (Structural Engineering, Annamalai Univ, Annamalai Nagar-600 002, Email: mag_rajabishek@rediff.com) : Innovative concrete using flyash and waste sheet glass. J Envir Res Dev 2009, 4(2), 476-83.

Examines the possibility of using the combination of waste Sheet Glass Powder as fine aggregate and Portland cement with 20% optimum replacement of flyash as cementitious binder offers an economically viable technology for high value utilization of industrial waste. Using of SGP in concrete is an interesting possibility for economy on waste disposal sites and conservation of natural resources. Natural sand was partially replaced (10%, 20%, 30%, 40% and 50%) with SGP and 20% optimum replacement of flyash in Portland cement. Compressive strength, Tensile strength (cubes and cylinders) and Flexural strength up to 180 days of age were compared with those of concrete made with natural fine aggregates. Fineness modulus, specific gravity, moisture content, water absorption, Bulk density, %voids, % porosity (loose and compact) state for sand (S) and SGP were also studied. The test results indicate that it is possible to manufacture low cost concrete containing Sheet glass powder (SGP) with characteristics similar to those of natural sand aggregate concrete provided that the percentage of SGP as fine aggregate up to 30% along with flyash 20% optimum in cement replacement can be used respectively.

8 illus, 1 table, 10 ref

017498   Lodhi A S;Kaushal A;Singh K G (Soil & Water Engineering Dep, Punjab Agricultural Univ, Ludhiana-141 004, Email: ajay0312@gmail.com) : Adoption of low tunnel technology for vegetable production. Envir Ecol 2009, 27(1A), 448-52.

Growing vegetable by low tunnel technology (row cover technology) has many advantages with regards to increase in yield, early harvesting of vegetables, conserving soil warmth, protecting plant from wind and frost and ultimately increasing the net profit for the farmers. This review provides better understanding and facilitates optimal analysis for rational use of low tunnel technology for vegetable production and will help to identify vegetables for adoption of low tunnel technology by farmers.

18 ref

017497   Liu Y (Mechanical Engineering Dep, Louisville Univ, Louisville, KY 40292, USA, Email: yucheng.liu@louisiana.edu) : Collapse behaviour and simplified modeling of triangular cross-section columns. Indian J Engng Mater Sci 2009, 16(2), 71-8.

This paper investigates and develops the collapse behaviours and characteristics of thin-walled columns with triangular cross-section under axial compression and pure bending. Two bending modes, inward bending and outward bending are discussed. The axial and bending resistances of the triangular columns arc formulated with mathematical equations of simple forms. Simplified finite clement models for the triangular columns are then developed based on the derived equations to simulate their axial buckling and bending collapse behaviours during crashes. The developed simplified models consist of beam elements and spring elements. Numerical results and comparisons show that the developed simplified models can replace detailed models in using for crashworthiness analysis and save a lot of computing time and modeling efforts. The presented simplified models and modeling efforts can be extensively applied in thin-walled structural analysis and design.

16 illus, 3 tables, 14 ref

017496   Liu J R;Jin B;Xie Y J;Chen Y;Weng Z T (The State Key Laboratory of Fluid Power Transmission and Control, Zhejiang Univ, Hangzhou 310027, China, Email: jinr.liu@gmail.com) : Investigation on the characteristics of a new high frequency three-way proportional pressure reducing valve in variable valve system or automobile engine. Indian J Engng Mater Sci 2009, 16(1), 7-13.

A new high frequency three way proportional pressure-reducing valve has been developed. By reducing the turns of the coil and using a high speed current amplifier, the responding time of the proportional solenoid is reduced to less than I ms. The steady and dynamic analyses show that the output pressure is proportional to the coil current and the dynamic bandwidth can be increased by increasing the coil current. An experimental system is built up and results well agreed with the theoretical and simulation analyses. The bandwidth of the valve is about 130 Hz at -3dB, which can meet the demand of automobile engine with maximum speed of 3000 rpm.

12 illus, 16 ref

017495   Li Y D;Zhang H C;Lee K Y (Mechanical Engineering Dep, Academy of Armored Force Engineeing, No. 21, Du-Jia-Kan, Chang-Xin-Dian, Beijing 100072, P.R. China, Email: kyl2813@gmail.com) : Fracture analysis for a non-homogeneous weldment with a crack parallel to the interface. Indian J Engng Mater Sci 2009, 16(5), 295-300.

Fracture modeling and analysis are of significance in the design and evaluation of weldments. Based on a new four-zone model, the present work performs anti-plane fracture analysis on a non-homogeneous weldment consisting of four different kinds of zones: base metal, heat affected zone (HAZ), fusion zone and weld metal. The HAZs and fusion zones are modeled as functionally graded materials. A crack parallel to the interface is assumed to be in the HAZ or weld metal. The crack problem is solved by the methods of Fourier integral transform and dual integral equation. Parametric studies on the stress intensity factors yield two conclusions for the current fracture model of the four-zone weldment. (i) The optimal value of the mismatch factor is 1.0. The increase in mismatch factor will decrease the driving force of a HAZ crack, but it will enhance that of a weld-metal crack. In engineering, mismatch factors too larger or too smaller than 1.0 should be avoided. (ii) The effect of non-homogeneity parameter embodies that of the relative stiffness of the crack-tip region. Stiffer crack-tip region may induce larger driving force for the crack.

5 illus, 24 ref

017494   Li J;Xia Y C (School of Mechanical & Electronic Engineering, Shanghai Second Polytechnic Univ, Shanghai-201 209 PR China, Email: xiayanchun2@sina.com) : Interfacial studies of polyamide 6 composites filled with oxidation carbon fibre. Indian J Engng Mater Sci 2009, 16(5), 319-25.

In this work, ozone modification method and air-oxidation are used for the surface treatment of polyacrylonitrile (PAN)-based carbon fiber. The surface characteristics of carbon fibers are characterized by X-ray photoelectron spectroscopy (XPS). The interfacial properties of carbon fiber reinforced polyamide 6 (CF/PA6) composites are investigated by means of the single fiber pull-out tests. As a result, it is found that IFSS values of the composites with ozone treated carbon fiber are increased by 60% compared to that without treatment. XPS results show that ozone treatment increases the amount of carboxyl groups on carbon fiber surface, thus the interfacial adhesion between carbon fiber and PA6 matrix is effectively promoted. The effect of surface treatment of carbon fibers on the tribological properties of CF/PA6 composites is investigated. Experimental results reveal that surface treatment can effectively improve the interfacial adhesion between carbon fiber and PA6 matrix. Thus, the wear resistance is significantly improved.

10 illus, 16 ref

017493   Kumar A;Kachhwaha S S;Mishra R S (Mechanical Engineering Dep, Delhi College of Engineering, Bawana Road, Delhi-110 042, Email: sskachhwaha@rediffmai.com) : Thermodynamic analysis of a regenerative gas turbine cogeneration plant. J scient ind Res 2010, 69(3), 225-31.

Design methodology lias been developed for parametric study and thermodynamic performance evaluation of a gas turbine cogensration system (GTCS). Parametric study showed that compression ratio (r_p), inlet air temperature, turbine inlet temperature, steam pressure and pinch point temperature played a very vital role on overall performance of GTCS. Exergy analysis revealed that most sensitive components in GTCS were combustion chamber and regenerator.

9 illus, 13 ref

017492   Korkut I;Yavuz K;Turgut Y (Technical Education Faculty, Gazi Univ, 06500, Besevler, Ankara, Turkey, Email: ikorkut@gazi.edu.tr) : Experimental investigation into the mechinability of GGG-70 grade spheroidal graphite cast iron. Indian J Engng Mater Sci 2009, 16(2), 116-22.

In this study, machining tests of the bearing necks of crank shafts produced from GGG-70 grade ductile iron (Dl) are carried out. Coated cemented carbide inserts are used in the machining tests. The tests arc carried out at four different cutting speeds (250, 275, 300 and 325 m/min). three different feed rates (0.15, 0.25 and 0.30 mm/rev) and two different depth of cuts (0.5 mm and 2 mm). The effects of these parameters on the surface roughness and the cutting force are investigated. Increasing cutting speed is found to deteriorate the surface roughness. The best average surface roughness values are obtained at 250 m/min which is the lowest cutting speed. Main cutting forces increased with increasing feed rate and depth of cut.

10 illus, 1 table, 10 ref

017491   Kolahan F;Heidari M (Mechanical Engineering Dep, Ferdowsi Univ of Mashhad, PO Box 91775-111, Mashhad, Iran, Email: kolahan@um.ac.in) : Modeling and optimization of MAG welding for gas pipelines using regression analysis and simulated annealing algorithm. J scient ind Res 2010, 69(4), 259-65.

Study established input-output relationships for metal active gas (MAG) welding for gas pipelines. Regression analysis (RA) was performed on data collected as per Taguchi design of experiments. Adequacy of RA model was verified using ANOVA method. RA model was then embedded into a simulated annealing (SA) algorithm to determine optimal process parameters for weld bead geometry specification. Proposed method is found quite effective in predicting process parameters for weld bead geometry.

3 illus, 4 tables, 17 ref

017490   Khurana A;Ranjan C K (NO, , C/o 56 APO, Air HQ, RK Puram, New Delhi) : Decompression chamber runs for screening and training of HALO paratroopers and training of fighter aircrew. Indian J Aerospace Med 2008, 52(2), 35-43.

Sneak missions dropping small groups of battle ready soldiers from high altitudes exposes paratroopers to pressure variations affecting the air containing cavities of the body. Evaluation of Eustachian tube functions, based on the ability to open the tube actively by various manoeuvres should be done by realistic simulation of flights in a pressure chamber to minimize the chances of Otitic barotrauma. The present study was carried out in two phases, Phase-I at Para Training School, Agra and Phase-II at Institute of Aerospace Medicine, Bangalore. In Phase-I, 25 healthy male trained paratroopers were examined for any signs or symptoms related to otitic barotrauma before and after a freefall from 12,500ft. In Phase-II, 50 Armed Forces healthy male paratroopers from Parachute Regiment Training Centre, Bangalore were chosen. An ear clearance run following standard briefings and monitoring was conducted simulating three protocols viz, 3000ft/min descent rate from 10,000ft to ground, 6000ft/ min and 1000'/min descent rate from an altitude of 12,500 ft. Tympanometry was done before and after each simulation and results compared amongst protocols using a non-parametric test for matched samples (McNemar's). In Phase-1,44% of the paratroopers showed signs of congestion whereas none reported any symptoms. In Phase-II, comparison of 3000ft/min vs 6000ft/min descent rate showed a statistically significant change in pain, discomfort and congestion whereas; tympanometry findings were not statistically significant. A significant difference in congestion was noted between 6000ft/min and 10,000ft/min descent rates. Pain, discomfort, congestion and tunpanometry findings between 3000ft/min and 1000ft/min were all statistically significant. In view of the findings, an ear clearance protocol with descent rates of I0,000ft/min from 12,500ft to ground level would be ideal for combat freefallers, as the pressure change is similar to that encountered during actual freefall. Given the limitation of the existing chambers and the insignificant difference in symptoms and tympanometry findings between the 6000ft/min and 10,000ft/min descent protocol, a 3000ft/min descent protocol followed by a 6000ft/min descent rate protocol, is acceptable for simulation for ear clearance run in combat freefallers. The findings of the study have implications for altitude chamber training of military aircrew as well as design protocols to be adapted in future generation of altitude chambers in the Armed Forces.

3 tables, 13 ref

017489   Khanuja S S;Baburaj V P (NO, , Naval Headquarters, New Delhi) : Civil aircraft disaster management on naval air station: challenges and concerns. Indian J Aerospace Med 2008, 52(2), 65-70.

4 illus, 2 tables, 12 ref

017488   Katiyar H;Bhattacharjee R (Electronica and Communication Engg. Dep, Indian Institute of Technology, Guwahati) : Power allocation strateies for non-regenerative relay network in Nakagami-m fading channel. IETE J Res 2009, 55(5), 205-11.

Cooperative relaying is a promising approach to enlarge coverage area and enhance system capacity. Capacity of such a system depends on the SNR of the received signal. Therefore, allocation of available power between source and relay, to achieve maximum SNR, is an important issue. A power allocation scheme depends not only on channel state information (CSI) but also on the degree of knowledge of this CSI. This paper investigates different power allocation strategies in presence of full CSI, without CSI, and statistical CSI through simulation studies. Knowledge of full CSI can be utilized to obtain optimal performance at the cost of system complexity. Use of statistical feedback reduces complexity and its performance is found to be close to optimal one. Its performance is close to optimum one for the placement of relay node near destination or with decrease in fading severity. However, in the absence of CSI, placement of relay at middle is the best solution, for similar channel conditions.

8 illus, 12 ref

017487   Karthigaikumar P;Baskaran K (Electronics and Communication Engineering Dep, Karunya Univ, Computer Science and Engineering Dep, Government College of Technology, Coimbatore) : FPGA-based law power audio subword sorter unit. IETE J Res 2009, 55(6), 260-5.

The security of audio data in high end communication applications like satellites and radars is an issue of concern these days. Designing a processor at the chip level for this requirement is by itself a challenge to VLSI engineers. This paper aims to design a HDL based novel audio subword sorter unit, which is less complex in structure and highly efficient in terms of security. In this paper, we examine the hardware implementation of powerful permutation instruction group (GRP) with low power. This is done at the integrated chip (IC-level) using Verilog HDL and can be implemented in FPGA. To our knowledge this is the first audio subword sorter unit implemented in FPGA.

7 illus, 1 table, 11 ref

017486   Kamath S;George V I;Vidyasagar S (Instrumentation and Control Engineering Dep, MIT, Manipal) : Simulation study on closed loop control algorithm of type 1 diabetes mellitus patients. IETE J Res 2009, 55(5), 230-5.

It is challenging to maintain normoglycemic range of glucose concentration in type I diabetic patients. In this study H∞ control is applied for insulin delivery to prevent the hyperglycemic levels in a type I diabetic patient. From a control theory point of view, the blood glucose regulation problem is reformulated as a tracking one. A glucose tolerance curve (GTC) validated from several patients is used as reference model. Intra- and inter-patient variability poses a challenging task to control blood glucose concentration in diabetic patients. We develop a data based robust controller to control blood glucose concentration in type I diabetic (TIDM) patients in the presence of meal disturbances under patient-model mismatch. Simulation studies are performed on the diabetic patient model under feedback control. It is seen that the proposed control strategy is able to control blood glucose concentration well within the acceptable limits and also compensate for slow parametric drifts.

7 illus, 22 ref

017485   Kamali A R;Hadi M;Samani M N (Materials Science and Engineering Dep, Malek ashtar Univ of Technology, Shahin-Shahr, Isfahan, Iran, Email: alirezakam@yahoo.com) : Two different methods for improving the properties of IC-221M alloy. Indian J Engng Mater Sci 2009, 16(6), 449-55.

Formation of the Ni-Ni₅Zr eutectic structure is the most important reason for the impoverished mechanical properties of the Ni₃Al-based alloy containing Zr. On the other hand, this low melting point phase has a positive effect on castability of the alloy. Two different methods are used in this study for the development of a Ni₅Zr-free structure. In the first method, arc remelting process, using Mo₃Al₈, ZrAl₃ and NiAl master alloys, followed by a proper heat treatment led to the production of a modified Ni₃Al-based alloy. In the second method, a powder metallurgy process is used to replace the casting method, thereby, lifting the need for Zr addition. A Ni₃Al-based alloy containing Mo, Cr, and B is produced via mechanical alloying followed by hot pressing densification. The alloys thus produced are studied for their improved yield strengths.

9 illus, 3 tables, 7 ref

017484   Kalyan Kumar G;Sreedhar U;Dodagoudar G R (Civil Engineering Dep, I.I.T. Madras, Chennai-600 036, Email: kalyanu.g@gmail.com) : Probabilistic seismic hazard analysis for low seismity region. Indian Geotech J 2009, 39(3), 288-316.

The estimation of probabilistic seismic hazard in low seismicity regions such as stable continental regions has to cope up with the difficulty in identification of active faults and with the low amount of available seismicity data. In this paper, an attempt is made to carry out probabilistic seismic hazard analysis (PSHA) for low seismicity region like Chennai city. The products of PSHA studies are estimates of ground motion parameters for chosen probabilities of occurrence, for a particular site or a region. Appropriate assumptions are made in the completeness analysis of the earthquake records as the seismicity data of the Chennai region is scarce. Due to poorly known attenuation characteristics of the study region, four attenuation relationships have been used for the estimation of peak ground acceleration. A few locations in the Chennai city are selected and seismic hazard results are presented in the form of hazard curves, which indicate the annual probability of exceeding the horizontal peak ground acceleration in a specified period of time. Uniform hazard spectra at different return periods are also provided for the time periods ranging from zero to one second. These spectra can be used to select the spectrum compatible acceleration time histories from the published data base of the actual ground motions.

16 illus, 10 tables, 60 ref

017483   Kali Shanker (NO, , K-1058, Aashiana Colony, Kanpur Road, Lucknow-226 012) : Propellants for space launch vehicles. Bhartiya Vaigyanik Evam Audyogik Anusandhan Patrika 2008, 16(2), 109-15.

Propellants are chemical mixtures which are burned inside the rockets for producing thrust and this mixture consists of a fuel and an oxidizer. Fuel is that substance which, if combined with an oxygen producing gas (for propulsion) starts burning. Oxydiser is an agent that releases oxygen for combination with a fuel. The ratio of the oxidizer and the fuel is called mixture ratio. Propellants are classified according their stales, namely liquid, solid or hybrid. The parameter by which the efficiency of a rocket is judged is called specific impulse. The specific impulse represents as to how many pounds (or kilograms) of thrust is generated by burning one pound (or one kilogram) propellant in one second. Specific impulse is the property of various propellants but its actual value, to some extent, goes on changing depending upon the design of rocket engine and the operating conditions.

6 illus, 2 tables, 7 ref

017482   Jha A K;Sinha S B;Upendra Kumar (Post Graduate Dep of Mathematics, Ranchi College, Ranchi-834 001) : Modelling testing effort for a flexible discrete software reliability growth models. Acta Cienc Indica-Math 2009, 35(2), 541-6.

Several software reliability growth models (SRGMs) have been developed in literature. Most of the models assume that testing effort expenditure are constant throughout software testing and uses calendar time or CPU time as the software error detection/removal period. This paper develops realistic software reliability growth models incorporating the effect of testing effort and usage number of test runs (cases) as the unit of software fault detection/removal period. The software error detection phenomenon in software testing is modeled by a non-homogeneous Poisson process. The behavior of the testing effort is described by a discrete Rayleigh curve. In this proposed discrete SRGM, we relate the number of faults detected/removed to the number of test runs (cases) during the testing phase by assuming the discrete failure intensity to the amount of current testing effort is proportional to the remaining error content in the software. Least square estimators and maximum likelihood estimators are used for the reliability growth parameters. The models are supported by numerical examples. Thus, the proposed models will enable us to evaluate software reliability more realistically.

2 illus, 12 ref

017481   Jayaprakash R;Perumal K;Arunkuma T;Sanjay Kumar;Selvakumar B (Solar Energy Laboratory, Physics Dep, Sri Ramakrishna Mission Vidyalaya, College of Arts and Science, Coimbatore-641 020) : Design and performance analysis of low cost solar still using transparent LDPE cover. J Envir Res Dev 2009, 4(2), 465-75.

Solar still is a device which allows to obtain fresh water from brackish water. This paper reports about the newly designed spherical solar still under climatic conditions and operational parameters in Coimbatore (11° N latitude), India. The performance of spherical solar still with two different thicknesses of low density polyethylene (LDPE) cover is analyzed. The spherical solar still was covered by low density polyethylene cover (LDPE) of thickness 0.176 mm and 0.107 mm respectively. The water temperature, air temperature, ambient temperatures are recorded at the regular intervals of time. The inside and outside of the cover temperatures are noted with solar radiation. The efficiency of the spherical solar still is analyzed for two thicknesses top cover. The internal heat transfer mode and external heat transfer mode are calculated. The hourly output yield per m^{2 of the still is calculated. This type of solar still is promoted for an easy utilization for rural people. The cost of designing of the spherical solar still is very much economical. The salient feature of this still is simple, low thermal capacity, lightweight and ease to operation.}

8 illus, 1 table, 13 ref

017480   Jaya V;Dodagoudar G R;Boominathan A (Civil Engineering Dep, I.I.T. Madras, Chennai-600 036, Email: boomi@iitm.ac.in ) : Seismic soil-structure interaction analysis of ventilation stack structure. Indian Geotech J 2009, 39(1), 116-34.

The seismic SSI responses of a ventilation stack are examined in terms of response spectra at different levels of the structure. A computer program named SASSI 2000 which employs the finite element method and flexible volume substructure method is used for the SSI analysis. For analysis, the ventilation stack is modelled as 3D lumped mass beam stick model. The rigid links represented by beams of large flexural and axial stiffness are used to connect the stick model to the corresponding location of the basemat. The basemat is modelled using 3D solid elements. The soil material properties are assumed to be viscoelastic with the complex modulus representation of the stiffness and damping properties of the soil layers. The stiffness and damping of each layer is adjusted using the equivalent linear method to consider the strain dependency of the soil properties. The SSI analysis of the ventilation stack is carried out with different ground conditions and foundation embedment. It is noted that the amplitude of spectral acceleration decreases about 25% by the foundation embedment and the frequency of the stack and soil system is slightly increased.

12 illus, 5 tables, 23 ref

017479   Jain P;Kumar B;Jain S B (Electronics and Communication Engg Dep, Indira Gandhi Institute of Technology, Kashmere Gate, New Delhi-110 006) : Unified recursive structure for forward and inverse modified DCT/DST/DHT. IETE J Res 2009, 55(4), 180-91.

This paper proposes implementation of the Modified Discrete Sine Transform (MDST) and Inverse MDST (IMDST) using recursive structures. The formulae required for recursive structures have been derived. Discrete Hartley Transform (DHT), a real-valued transform, is closely related to Discrete Fourier Transform (DFT) of a real-valued sequence and hence its use as an alternative to the Fourier Transform avoids complex arithmetic. This paper presents Modified Discrete Hartley Transform (MDHT)/lnverse MDHT (IMDHT) using Modified Discrete Cosine Transform (MDCT)/ Inverse MDCT (IMDCT) and MDST/lnverse MDST (IMDST) recursive structures. The proposed structures are used for simultaneous computation of MDCT/MDST/MDHT of length N (divisible by four) and their Inverse (IMDST/IMDHT). The proposed structures are parallel, simple, regular and therefore highly suitable for VLSI implementation.

3 illus, 1 table, 28 ref

017478   Jagadeesha T;Kim L;Gonsalvis J;Gowda T (Mechanical Engineering Dep, St. Joseph Engineering College, Mangalore-575 028, Email: Jagdishsg@yahoo.com) : Innovative low pressure borophosphosilicate glass processes for nano devices. Indian J Engng Mater Sci 2009, 16(5), 341-6.

Doping of oxide with phosphorous can trap mobile ions and reduce the re-flow temperature. By adding boron the reflow temperature can be reduced further without excessive phosphorous, which may cause metal corrosion. Borophosphosilicate glass (BPSG) and phosphosilicate glass (PSG) processes are mainly used for premetal dielectric (PMD) applications. In the present study, a new low pressure BPSG process has been developed which can be used for Flash memory and Logic devices. It is shown that films with phosphorus and boron concentrations in the range of 1.85-9.15 elemental wt% are deposited with film thickness 6000 Angustrum BPSG and 100 Torr process has been found to achieve more stable film thickness. Decreasing the deposition pressure from 200 to 100 Torr results in a 50% increase in the deposition rate of twin-wafer SACVD BPSG and has zero effect on film properties. Throughput has been improvement by 20% on SACVD PMD BPSG application.

11 illus, 4 tables, 13 ref

017477   Gupta M;Rana R S (Hill Agricultural Research & Extension Centre, CSK HPKV, Dhaulakuan, District Sirmour, Himachal Pradesh-173 001) : Rainwater harvesting in hilly areas. Indian Fmg 2008, 58(8), 25-8.

Himachal Pradesh is a predominantly agrarian state and its climatic conditions are suitable for the cultivation of a wide range of horticultural and vegetable crops. But lack of irrigation facilities is emerging as a bottleneck. Conventional irrigation methods like canals, tube-wells are not feasible in the state due to mountainous terrain. Rainwater harvesting offers a ray of hope for mitigating water crisis.

4 tables

017476   Gosavi M;Saran S;Mittal S (Civil Engg Dep, College of Technology, G.B. Pant Univ of Agriculture and Technology, Pantnagar, U.S. Nagar-263 145, Email: meenalgulati@rediffmail.com) : Model tests for validation of analysis of nailed cuts. Indian Geotech J 2009, 39(1), 96-116.

Validates the theoretical procedure with results from model tests. For this purpose two models of nailed open cuts have been made. The heights of cuts were kept 1.0 m and 2.0 m respectively. Each model was supported with nails in tow configuration giving the F.O.S. more than 1.5. The backfill of these models were surcharged with uniform load till the failure of model cuts occurred. The F.O.S of these cuts at these surcharge intensities were obtained by the developed analysis and found very close to unity thus validating the analysis.

8 illus, 14 ref

017475   Ghazvinloo H R;Raouf A H;Shadfar N (Materials Engineering Dep, Semnan Univ, Semnan, Iran, Email: hamid.ghazvinloo@gmail.com) : Effect of arc voltage, welding current and welding speed on fatigue life, impact energy and bead penetration of AA6061 joints produced by ronotic MIG welding. Indian J Sci Technol 2010, 3(2), 156-62.

Heat treatable wrought aluminum-magnesium-silicon alloys forming to AA6061 have gathered wide acceptance in the fabrication of light weight structures requiring a high strength-to weight ratio and good corrosion resistance. The effect of processing parameters on fatigue life, impact energy and bead penetration of AA6061 joints produced by MIG robotic welding was analyzed in the present study. Different samples obtained by employing arc voltages of 20, 23 and 26 V, welding currents of 110, 130 and 150 A, welding speeds of 50, 60 and 70 cm/min were produced. After finishing of the welding process, the mechanical properties of the joints were evaluated by means of fatigue and impact tests at room temperature. Finally, depth of weld penetration was measured in samples. Results were clearly illustrated that as heat input increases fatigue life decreases whereas impact energy increases slightly and then drops significantly, A linear increase in depth of penetration with increasing welding current and arc voltage was also observed. The biggest penetration we observed was in 60 cm/min welding speed.

13 illus, 4 tables, 21 ref

017474   Ghasemi A;Farsani M M;Nezamabadi Pour H (Electrical Engineering Dep, Shahid Bahonar Univ of Kerman, Kerman, Iran, Email: nezam@mail.uk.ac.ir) : Unit commitment scheduling using binary differential evolution algorithm. Opsearch 2009, 46(1), 108-22.

This paper presents a new approach for thermal generating units scheduling using binary differential evolution (BDE) algorithm. Solving the unit commitment (UC) problem by BDE is a two stage process. In the first stage, the economic dispatch of the units are solved and hourly optimum solution of UC is obtained considering all constraints except the minimum up time (MUT) and minimum down time (MDT) constraints. In the second stage, the MUT and MDT are enforced by defining a probability function followed by modifying the schedule obtained in the first step. To validate the results obtained by BDE, a version of genetic algorithm (GA), namely as, PNUCO is applied for comparison. Also, the results obtained by BDE and PNUCO are compared with the previous approaches reported in the literature. The results show that the BDE produces optimal or nearly optimal solutions for the study systems.

4 tables, 37 ref

017473   Dubey M;Rajput S P S (Mechanical Engineering Dep, MANIT, Bhopal-462 051, Email: d.maneesh@gmail.com) : Organic Rankine cycle powered compression refrigeration cycle : an exergetic model. J Envir Res Dev 2009, 4(2), 559-71.

The conventional approach followed for the evaluation of a coupled power-refrigeration cycle using the first law of thermodynamics is proposed to be substituted by analyzing it from the viewpoint of second law of thermodynamics. This paper describes that exergy clearly identifies efficiency improvements and reductions in thermodynamic losses paving the way for the adoption of green technologies. Exergy can be used to assess and improve energy systems by providing more useful and meaningful information than energy analysis. This article focuses on the development and state-of-the art of exergy analysis by leveraging conventional concepts. The thermodynamic models for energy and exergy analysis for computing performance parameters are presented in this paper.

^iia5 illus, 1 table, 20 ref

017472   Dewaikar D M;Sawant V A;Chore H S;Halkude S A (Civil Engineering Dep, Indian Institute of Technology Bombay, Powai, Mumbai-400 076, Email: dmde@civil.itb.ac.in) : Active thrust on bracing system of open cuts in soil. Indian Geotech J 2009, 39(2), 201-15.

An analysis based on Kotter's (1903) equation is proposed for the computation of active thrust and its point of application in respect of bracing system of open cuts in a cohesive-frictional (c-φ) soil. The distinctive feature of this analysis is that it identifies the unique failure surface on the basis of force equilibrium condition and gives the corresponding active thrust which is uniquely determined. Moment equilibrium condition is used to compute point of application of the active thrust. The marked influence of the angle of internal friction of soil on active earth pressure coefficient is clearly seen from the results obtained for a cohesive- frictional (c- φ) soil. The location of point of application of active thrust is also found to be sensitive to the variation in soil cohesion. Computed values of location of point application of active thrust show a fairly good agreement with the values reported on the basis of some theoretical considerations and field measurements.

4 illus, 2 tables, 6 ref

017471   Dewaikar D M;Chore H S;Salimath R S (Civil Engineering Dep, Indian Institute of Technology Bombay, Powai, Mumbai-400 076, Email: dmde@civil.iitb.ac.in) : Pile driveability analysis using GRLWEAP. Indian Geotech J 2009, 39(2), 227-39.

Modern pile design is an interactive process involving structural, geotechnical, and constructability considerations. Pile driveability refers to the ability of a pile to be safely (i.e., without damage) and economically (i.e., with reasonably sized construction equipment and without excessive blow counts) driven to support the required bearing capacity and possibly to a minimum required penetration depth. In this paper, a parametric study based on the important parameters of pile, soil and driving hammer, which affect the driveability is presented. The analysis is carried out using GRLWEAP (GRL Wave equation analysis of pile) version 2005 software developed by Pile Dynamics, Inc.

^ssc 9 illus, 1 table, 23 ref

017470   Dash P K;Panigrahi B K;Hasan S (NO, Silicon Institute of Technology, Bhubaneswar, Orissa) : Hybrid particle swarm optimization and unscented filtering technique for estimation of non-stationary signal parameters. IETE J Res 2009, 55(6), 266-74.

This paper proposes an adaptive unscented Kalman filter for parameter estimation of non-stationary signals, like amplitude and frequency, in the presence of significant noise and harmonics. This paper proposes an iterative update equation for model and measurement error covariances Q and R to improve tracking of the filter in the presence of high noise. The initial choice of the model and measurement error covariances Q and R, along with the UKF parameters, are crucial in noise rejection. This paper utilizes a modified particle swarm optimization (MPSO) algorithm for the initial choice of the error covariances and UKF parameters. Various simulation results for time varying signals reveal significant improvement in noise rejection and accuracy in obtaining the frequency and amplitude of the signal.

12 illus 3 tables, 9 ref

017469   Chavan Y V;Mishra D K (Assistant Professor in Electronics and Telecommunication, Maharashtra Academy of Engineering, Alandi(D), Pune) : Improved complementary metal oxide semiconductor digital pixel sensor. IETE J Res 2009, 55(5), 222-9.

Charge Coupled Devices (CCDs) are used in imaging as they have advantages over conventional bulky tube type TV cameras. The complementary metal oxide semiconductor (CMOS) based image sensors, passive pixel sensors (PPS), and active pixel sensor (APS) have advantages in implementation. This makes the APS competitive with CCDs. However, APS is not popular because of the poor fill factor and lack of resolution. With the development of image sensor technology, digital pixel sensor (DPS) has overcome all problems associated with CCDs and CMOS-APS image sensor. In DPS, comparator and memory are implemented on chip for each pixel. This results in benefits in terms of power, pixel size, fill factor and resolutions. This paper analyses earlier DPS pixel with an analog comparator and inverter-based comparator. The limitations reported in the analysis of analog comparator are overcome using cascaded CMOS inverter-based comparator. The cascaded CMOS inverter is built with proper adjustment of Width (W) to Length (L) ratio. This adjustment sets the threshold voltage 'V_th' that remains fixed for the pixel (in our case V_th is equal to 2.2V). This cascaded inverter based comparator is called as threshold inverter quantizer (TIQ) and is further analyzed with biasing for high gain. Four-pixel and 16-pixel array design is done using TIQ based pixel. Extensive simulation of the TIQ based pixel array is done and results are reported for current and power dissipation.

11 illus, 3 tables, 21 ref

017468   Chavan P V;Batista J R;Shepherd W (Civil and Environmental Engineering Dep, Nevada Univ, Las Vegas, USA, Email: mailpvc@yahoo.com) : Application of sludge blanket height and flux theory as a tool to control denitrification in the secondary clarifier. J Envir Res Dev 2007, 2(2), 111-17.

This study was performed in a full-scale biological nutrient removal wastewater treatment plant at the Clark County Sanitation District (CCSD), Las Vegas, Nevada, USA. The use of concepts of solid flux and state point analysis as an operational tool to control denitrification in clarifier of BNR systems was attempted in this study. Biological nutrient removal system in this plant worked well (> 95% removal for nutrients and > 97% for total suspended solids removal (TSS)); however, the system occasionally suffered some instability and sporadic phosphorus-excursion. The plant effluent were discharged into the Las Vegas Wash, which flows into Lake Mead, a national recreational area and the primary source of drinking water supply to the entire valley. Hence, CCSD has to be operated under strict regulation for nutrient removal in order to avoid eutrophication of the Lake. The results showed that solids flux had influence on dissolved oxygen (DO), TSS, and SBH in the clarifier. The DO decreased with the increase in the solid flux, while TSS increased as the solid flux increased. The increase in the SBH was observed as a consequence of increased solid flux. The results indicated that the solid flux, state point analysis, and SBH could be used as operating tools for the control of denitrification occurring within clarifiers. The data generated in this research was used as the starting point to control denitrification in the clarifiers at CCSD.

6 illus, 12 ref