In-house development of co-fireable thick film silver conductor for LTCC applications

The rapidly growing wireless industry needs new high performance materials to build low loss, high density, and thermally stable integrated packages. Applications include automotive safety, control, global positioning system (GPS) mapping and entertainment, multifunctional portable phones, video and data transmission through wireless local area network (WLAN) etc. Recently, low temperature co-fired ceramics (LTCC) technology is referred as a key approach for smart packaging. Although its use has been initiated in the telecommunication field due to the excellent dielectric properties of the LTCC tapes, its application areas have been diversified recently. In the present work, the attempt has been made towards the development of thick film silver conductor composition compatible with available LTCC tapes (DuPont DP-951AX). The physical, microstructural, and electrical properties of the pastes prepared with different compositions are presented in this paper.     

The effect of mechanical stress on permeability of concrete: A review

The presence of aggressive fluids and their transport is by far the most important factor controlling the durability of cement based composites. In structural concrete, the application of mechanical stress leads to cracking, which in turn affects the transport properties adversely, but very little is known of this influence. The paper highlights the vast discrepancy between experimentally determined permeability data, which appear to be largely artifacts of disparate test procedures. In particular, it is not clear if an equilibrium was attained in the fluid flow and further, whether the flow measurements were made in the presence of the applied stress, which together make it very difficult to compare experimental data. Nevertheless it is clear that stress induced cracking leads to a surge in fluid flow and there exists a threshold value for both the applied stress and the resultant crack width associated with fluid permeability in concrete.     

Stochastic approximation with ‘controlled Markov’ noise

Stochastic approximation algorithms with additional noise that can be modelled as a controlled Markov process are analyzed and shown to track the solutions of a differential inclusion defined in terms of the ergodic occupation measures associated with the controlled Markov process.     

Use of mass spectrometry to characterize proteolysis in cheese

A rapid method for characterizing proteolysis in different cheese varieties was developed using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-ToF-MS). pH 4.6-soluble extracts of different cheese varieties were sub-fractionated using ethanol and 70% ethanol-soluble extracts were analyzed using MALDI-ToF-MS. Sample analysis time was ∼3 min compared to ∼100 min for reversed-phase HPLC; moreover, the method yielded accurate molecular masses of peptides originating as a result of proteolysis. Small peptides (<3500 m/z) were monitored and data for relative intensities of peptides were analyzed using multidimensional scaling (MDS) to demonstrate the similarity between profiles obtained from different cheese varieties. The similarities between the profiles of MALDI-ToF mass spectra were demonstrated in a two-dimensional space by performing MDS on the similarity matrix. Use of MALDI-ToF-MS is thus a fast and effective method for monitoring small peptides produced in cheese as a result of proteolysis.     

A comparison study of energy and exergy performance of a hybrid photovoltaic double‐pass and single‐pass air collector

In this present paper, analysis based on energy and exergy of double‐pass hybrid photovoltaic thermal (HPV/T) air collector having air flow in the opposite direction in ducts has been carried out based on initial cost, annual savings and return on investment. Choice of the location is made to cover different climatic conditions prevailing in India e.g. hot and dry climate represented by Jodhpur, warm and humid climate represented by Mumbai, moderate climate represented by Bangalore, cold and cloudy climate represented by Srinagar and composite climate represented by New Delhi. Results of single‐pass HPV/T air collector have also been compared. It is observed that electrical, thermal and exergy efficiencies of double‐pass HPV/T air collector are higher than that of single‐pass HPV/T air collector by 10–12, 40–45 and 13–17%, respectively. Further, it is observed that cost per kWh of double‐pass HPV/T air collector reduces for all the locations covered in the study when compared with cost per kWh of single‐pass HPV/T air collector. Copyright © 2009 John Wiley & Sons, Ltd.     

Chemical composition and in vitro control of agricultural plant pathogens by the essential oil and various extracts of Nandina domestica Thunb.

BACKGROUND: The aims of this study were to examine the chemical composition of the essential oil isolated from the floral parts of Nandina domestica Thunb. by hydrodistillation, and to test the efficacy of essential oil and various leaf extracts (n‐hexane, chloroform, ethyl acetate and methanol) as an antifungal potential against a panel of agricultural plant pathogens. RESULTS: The GC‐MS analysis determined that 79 compounds, which represented 87.06% of total oil, were present in the oil containing mainly 1‐indolizino carbazole (19.65%), 2‐pentanone (16.4%), mono phenol (12.1%), aziridine (9.01%), methylcarbinol (4.6%), ethanone (3.3%), furfural (2.96%), 3,5‐dimethylpyrazole (1.29%) and 2(5H)‐furanone (1.32%). The oil (1000 ppm disc^?1) and the leaf extracts (1500 ppm disc^?1) revealed remarkable antifungal effect against Fusarium oxysporum, Fusarium solani, Phytophthora capsici, Colletotrichum capsici, Sclerotinia sclerotiorum, Botrytis cinerea and Rhizoctonia solani in the growth inhibition range of 53.3–64.3% and 33.3–56.0%, respectively, along with their respective values for mimimum inhibitory concentration (MIC) ranging from 125 to 1000 µg mL^?1 and 500 to 2000 µg mL^?1. The values for minimal fungicidal concentration (MFC) of the oil and extracts were obtained in the range of 125 to 1000 µg mL^?1 and 500 to 2000 µg mL^?1, respectively. The essential oil also had a strong detrimental effect on spore germination of all the plant pathogens tested along with concentration as well as time‐dependent kinetic inhibition of B. cinerea. CONCLUSION: The results obtained in this study demonstrate that N. domestica mediated oil and extracts could become potential alternatives to synthetic fungicides for controlling certain important agricultural plant pathogenic fungi. Copyright © 2008 Society of Chemical Industry     

Comparative analysis of chipping mechanics of float glass during rotary ultrasonic drilling and conventional drilling: For multi-shaped tools

Float glass has immense applications such as sensor glass, micro-processor glass and decorative glass; because of its exceptional wear resistance, chemical and thermal characteristics. Nevertheless, researchers are still bearing decisive issues, which affect its application. These issues are profile inaccuracy and chipping because of its poor machining characteristics and hence high precision machining. The objective of the present study is to condemn the chipping related hindrances while using multi-shaped diamond abrasive tools to create blind holes. The tools, which applied, are named as hollow abrasive tool, pinpointed conical tool, flat cylindrical tools and concave circular tool. The experimental trials were performed by rotary ultrasonic drilling (RUD) and CNC conventional drilling (CD). The actual industrial conditions and parameters were considered throughout the experimentation. Physics behind the formation of chipping on hole periphery by RUD and CD are revealed. In addition, individual mechanisms of multi-shape tools with respect to chipping are analyzed. The results show that RUD process has attained the smallest measurement of chip radial distance as compared to CD for all types of tool. Finally, the concave circular tool is found as the best tool particularly to get least chip radial distance during drilling i.e. 0.1145?mm.