Thermo-rheological analysis of various chain extended recycled poly(ethylene terephthalate)

Three chain extenders, pyromellitic dianhydride (PMDA), ethylene carbonate (EC), and a polymeric-epoxide, were investigated for improving recycled p(ethylene terephthalate) (r-PET) properties with melt extrusion. The amount of additives and processing temperatures were also varied to check for melt degradation. Small amplitude oscillatory shear experiments were performed to probe rheological changes with different chain extenders. Capillary rheometry with haul-off was also performed to measure extensional viscosity and melt strength. Higher loadings of the chain extenders were found to improve properties of r-PET. These chain extenders definitely increased melt viscosities when incorporated at the higher level of the ranges examined, matching that of virgin PET. EC addition resulted in high shear thinning of the polymer. Epoxy and PMDA added to r-PET produced products with the same extensional viscosity as v-PET. Haul-off experiments demonstrate superior performance by epoxy-modified r-PET compared to v-PET.     

Analysis and assessment of a nanoparticle seeded small scale absorption refrigeration system driven by a low‐grade waste heat source

The thermoeconomic behaviour of a nanoparticle seeded single effect LiBr‐H₂O absorption refrigeration system (ARS) is investigated for a small scale application. In the proposed method, alumina nanoparticles with volume concentrations of 3%, 5%, and 7% are dispersed into an aqua lithium bromide solution. The multiobjective heat transfer search algorithm is employed to examine the design trade‐off between the coefficient of performance (COP) and total annualized cost (TAC). To analyze the overall performance of the system, the influence of five design parameters, namely the temperatures of the generator, absorber, evaporator, condenser and heat exchanger pipe diameter, are studied. It is found that with an increase in the COP, the TAC of the system is initially raised marginally, and after that, raised rigorously with further increment. The comparative results indicate that the COP and TAC of the nanofluid based ARS system are increased by about 7% and decreased by about 3.2%, respectively, corresponding to the Pareto points of the base ARS system. A lower break‐even point of about 2.6 years is achieved for the ARS system containing nanoparticles compared to the base ARS system. Overall, the ARS system containing 5% nanoparticles is the best solution from a thermodynamic and economic point of view.     

Cascode Monolithic DC-DC Converter for Reliable Operation at High Input Voltages

A CMOS OTA-C low-pass notch filter for EEG application is described. The pass-band covers four bands of brain wave and provides more than 65 dB attenuation for the 50 Hz power line interference. The OTA works in the weak inversion region and a low transconductance of 3 nA/V is achieved. The low transconductance enables using small capacitors in the OTA-C filter so that the filter is suitable for the multi-channel EEG integrated circuits. The measured results show the good performance of the filter for filtering the noise in acquired EEG signals. Xinbo Qian received the B.Sc. degree from Beijing Institute of Technology, P.R. China, in 1991 and M.Sc. degree from Institute of Physics, Chinese Academy of Sciences, in 1996. From 1996 to 1999, she was a research engineer in the Institute of Acoustics, Chinese Academy of Sciences, worked on the sonar signal receiving and processing systems. Since 1999, she has been pursuing the Ph.D. degree in Electrical and Computer Engineering department, National University of Singapore, with research direction on on-chip readout circuits for microbolometer focal plane arrays. Now she is employed by Department of Mechanical Engineering and Division of Bioengineering, National University of Singapore as a research fellow. Her research interest is low-noise integrated circuits design and bio-medical sensor electronics, including electroencephalography IC, magnetocardiography IC, low-noise amplifier, filter and data converters etc. Yong Ping Xu graduated from Nanjing University, P.R. China in 1977. He received his Ph.D. from University of New South Wales (UNSW) Australia, in 1994. From 1978 to 1987, he was with Qingdao Semiconductor Research Institute, P.R. China, initially as an IC design engineer, and later the deputy R&D manager and the Director. From 1989 to 1992, he was working on silicon diode based infrared detectors towards his Ph.D. at School of Electrical Engineering, UNSW Australia. From 1993 to 1995, he worked on an industry collaboration project with GEC Marconi, Sydney, Australia, at the same university, involved in design of sigma-delta ADCs. He was a lecturer at University of South Australia, Adelaide, Australia from 1996 to 1998. He has been with the Department of Electrical and Computer Engineering, National University of Singapore since June 1998 and is now an Associate Professor. His general research interests are in the areas of mixed-signal and RF integrated circuits, and integrated MEMS and sensing systems. His current focuses are high-speed wideband ADC, UWB front-end circuits and low-power low-voltage integrated circuits for biomedical applications. He is a Senior Member of IEEE. Xiaoping Li received his Ph.D. degree from Department of Mechanical and Manufacturing Engineering, University of New South Wales, Australia in 1991, and joined the National University of Singapore in 1992, where he is currently an Associate Professor with the Department of Mechanical Engineering and Division of Bioengineering. He was a visiting professor of Tokyo Institute of Technology, Japan in 2000, and visiting professor of Georgia Institute of Technology, USA in 2001. He is a member of American Society of Mechanical Engineers (ASME), a senior member of Society of Manufacturing Engineering (SME) and a senior member of North American Manufacturing Research Institute/SME, and is currently the Chairman of SME Singapore Chapter. His current research interests include neurosensors and nanomachining. He is a guest editor of International Journal of Computer Applications in Technology, USA. He is a regular reviewer of the ASME Journal of Manufacturing Engineering, USA, Transactions of NAMRI/SME, USA, Journal of materials processing technology, UK, International Journal of Machine Tools and Manufacture, UK, and IMechE Journal of Engineering Manufacture, UK.     

Development and Validation of HPTLC Method for Estimation of Tacrolimus in Formulations

A new, simple, and rapid high-performance thin-layer chromatographic method with a derivatization procedure was developed and validated for quantitative determination of tacrolimus. Tacrolimus was chromatographed on silica gel 60 F₂₅₄ TLC plate using toluene–acetonitrile–glacial acetic acid (6:4:0.1, by volume) as mobile phase. Tacrolimus was visualized using a derivatization reagent containing anisaldehyde–sulfuric acid in absolute alcohol and quantified by densitometric analysis in the reflectance mode at 675 nm. The method was found to give compact spots for the drug (R_f?=?0.40?±?0.03). The linear regression analysis data for the calibration plots showed good linear relationship with r²?=?.9989 in the concentration range 100–800 ng/spot. The method was validated for precision, recovery, repeatability, and robustness as per the International Conference on Harmonization guidelines. The minimum detectable amount was found to be 28.90 ng, whereas the limit of quantitation was found to be 97.04 ng. Statistical analysis of the data showed that the method is precise, accurate, reproducible, and selective for the analysis of tacrolimus. The method was successfully employed for the estimation of equilibrium solubility and quantification of tacrolimus as a bulk drug and in commercially available capsules and in-house developed self-microemulsifying formulations.     

SRAM dynamic stability estimation using MPFP and its applications

In this paper, an accurate approach for estimating the dynamic stability of static random access memory (SRAM) is proposed. The conventional methods of SRAM stability estimation suffer from two major drawbacks: (1) using static failure criteria, such as SNM, which does not capture the transient and dynamic behavior of SRAM operation, and (2) using quasi-Monte-Carlo simulation, which approximates the failure distribution, resulting in large errors at the tails where the desired failure probabilities exist. These drawbacks are eliminated by employing accurate simulation-based dynamic failure criteria along with a new distribution-independent, Most-probable-failure-point search technique for accurate probability calculation. Compared to previously published techniques, the proposed dynamic stability technique offers orders of magnitude improvement in accuracy. Furthermore, the proposed dynamic stability technique enables the correct evaluation of stability in real operation conditions and for different dynamic circuit techniques, such as dynamic write back, where the conventional methods are not applicable.     

Automating IEEE 1500 Core Test—An EDA Perspective

Editor's note:Standardized design and test practices enable automation. This article describes a methodology and corresponding tool set that combines automated support for IEEE Std 1500 and test data compression in one.—Erik Jan Marinissen, IMEC     

TrkB Receptor Signalling: Implications in Neurodegenerative,Psychiatric and Proliferative Disorders

The Trk family of receptors play a wide variety of roles in physiological and disease processes in both neuronal and non-neuronal tissues. Amongst these the TrkB receptor in particular has attracted major attention due to its critical role in signalling for brain derived neurotrophic factor (BDNF), neurotrophin-3 (NT3) and neurotrophin-4 (NT4). TrkB signalling is indispensable for the survival, development and synaptic plasticity of several subtypes of neurons in the nervous system. Substantial evidence has emerged over the last decade about the involvement of aberrant TrkB signalling and its compromise in various neuropsychiatric and degenerative conditions. Unusual changes in TrkB signalling pathway have also been observed and implicated in a range of cancers. Variations in TrkB pathway have been observed in obesity and hyperphagia related disorders as well. Both BDNF and TrkB have been shown to play critical roles in the survival of retinal ganglion cells in the retina. The ability to specifically modulate TrkB signalling can be critical in various pathological scenarios associated with this pathway. In this review, we discuss the mechanisms underlying TrkB signalling, disease implications and explore plausible ameliorative or preventive approaches.     

Antibacterial mode of action of seed essential oil of Eleutherococcus senticosus against foodborne pathogens

This study investigated the antibacterial mechanism of action of the seed essential oil of Eleutherococcus senticosus (ESEO) against foodborne pathogenic bacteria. Preliminarily, the ESEO (1000 μg disc^?1) showed potential antibacterial effect as diameter of inhibition zones (12.0 ± 0.2–37.0 ± 2.0 mm) against the tested foodborne pathogens. The MIC and MBC values of ESEO against the tested bacteria were found in the range of 125–500 and 500–1000 μg mL^?1, respectively. At MIC concentration, the ESEO had potential inhibitory effect on the cell viability of the tested pathogens. In addition, SEM analysis showed the inhibitory effect of ESEO as confirmed by considerable morphological alterations on the cell wall of B. cereus ATCC 13061 and E. coli O157:H7 ATCC 43889. Moreover, the ESEO revealed its mode of action against foodborne pathogens on membrane integrity as confirmed by release of extracellular ATP, 260‐nm absorbing materials and leakage of potassium ions. These findings confirm that the ESEO can be used as a potential antibacterial agent in food industry to inhibit the growth of various foodborne pathogens.     

Global warming potential of the sulfur–iodine process using life cycle assessment methodology

A life cycle assessment (LCA) of one proposed method of hydrogen production – thermochemical water-splitting using the sulfur–iodine cycle couple with a very high-temperature nuclear reactor – is presented in this paper. Thermochemical water-splitting theoretically offers a higher overall efficiency than high-temperature electrolysis of water because heat from the nuclear reactor is provided directly to the hydrogen generation process, instead of using the intermediate step of generating electricity. The primary heat source for the S–I cycle is an advanced nuclear reactor operating at temperatures corresponding to those required by the sulfur–iodine process. This LCA examines the environmental impact of the combined advanced nuclear and hydrogen generation plants and focuses on quantifying the emissions of carbon dioxide per kilogram of hydrogen produced. The results are presented in terms of global warming potential (GWP). The GWP of the system is 2500 g carbon dioxide-equivalent (CO₂-eq) per kilogram of hydrogen produced. The GWP of this process is approximately one-sixth of that for hydrogen production by steam reforming of natural gas, and is comparable to producing hydrogen from wind- or hydro-electric conventional electrolysis.