Effect of various meandering slots in rectangular microstrip antenna ground plane for compact broadband operation

The study of the effect of various meandering slots in the rectangular microstrip antenna ground plane for compact broadband operation is presented. The rectangular microstrip antenna is meandered using three different types of ground plane meandering slots: (a) smaller meandering slots, (b) longer meandering slots, and (c) open-end meandering slots, and is studied experimentally and compared. In these meandering slots, the open-end meandering slot is proved to be effective in significantly enhancing the bandwidth of a compact meandered antenna. Using open-end meandering slots in the ground plane, an extreme compactness of 83% with a broad bandwidth of 38.3% is obtained.     

13C CP/MAS NMR Spectroscopy of Native and Acid Modified Starches

¹³CP/MAS NMR spectroscopic studies of some starches from cereals (wheat, maize and finger millet), pulses (green gram, chick pea), tuber (potato) and root (tapioca), and their respective acid (HCI, HNO₃) modified starches were carried out. While cereal starches exhibited a triplet signal for their anomeric carbons, pulse, tuber and root starches showed doublets. Line width changes in signals indicated that debranching in the above modified starches led to narrowing of C₆ signals (more pronounced in the case of potato and tapioca starches) and were consistent with the release of branching strains. Potato starch, both native and modified, was found to be different from other starches as inferred from the chemical shift values for their anomeric carbons and line shape. The dihedral angle (ϕ′2) calculated from chemical shift values for C₁ and conformation of dihedral angel (x) as predicted from chemical shift of C₆ are discussed with respect to structural organization.     

Impact of coal mining on mine water quality

The coal mining industry has to dispose of millions of litres of water every day. This water forms main source of various water supplies in the thickly populated coalfields. In this study, water samples from major coalfields were collected and analysed in an attempt to reflect the impact of mining on water quality in these areas. Various physico-chemical characteristics of mine waters as analysed include pH, alkalinity/acidity, specific conductivity, hardness, total solids, sulphate, chloride iron and trace materials. This investigation reveals that mining activity, markedly pollute the mine waters. Mine waters are of highly complex nature and of widely varying composition. These are nearly neutral, alkaline, mildly acidic and highly acidic in nature. Special emphasis on water quality deterioration due to acid mine drainage which result in significant concentration levels of tract (toxic) metals, is given. A classification of these mine waters is also made.     

Lipid composition ofCalophyllum inophyllum kernel

Total kernel lipids extracted fromCalophyllum inophyllum, Guttifereae amounted to 60.1% of the dry kernel. The total lipids consisted of 92.0% of neutral lipids, 6.4% glycolipids and 1.6% phospholipids. Neutral lipids consisted of triacylglycerols (82.3%), free fatty acids (7.4%) and small amounts of diacylglycerols, monoacylglycerols and sterols. At least four glycolipids and five phospholipids were identified. Acylmonogalactosyldiacylglycerol and monogalactosylmonoacylglycerol were major glycolipids; while monogalactosyldiacylglycerol and an acylated sterolglucoside were present in small amounts. The phospholipids consisted of phosphatidylethanolamine and phosphatidylcholine as major phospholipids, and minor amounts of phosphatidic acid, phosphatidylserine and lysophosphatidylcholine. The fatty acid composition of these different neutral lipids, glycolipids and phospholipids was determined.     

Biometric cryptosystems: issues and challenges

In traditional cryptosystems, user authentication is based on possession of secret keys; the method falls apart if the keys are not kept secret (i.e., shared with non-legitimate users). Further, keys can be forgotten, lost, or stolen and, thus, cannot provide non-repudiation. Current authentication systems based on physiological and behavioral characteristics of persons (known as biometrics), such as fingerprints, inherently provide solutions to many of these problems and may replace the authentication component of traditional cryptosystems. We present various methods that monolithically bind a cryptographic key with the biometric template of a user stored in the database in such a way that the key cannot be revealed without a successful biometric authentication. We assess the performance of one of these biometric key binding/generation algorithms using the fingerprint biometric. We illustrate the challenges involved in biometric key generation primarily due to drastic acquisition variations in the representation of a biometric identifier and the imperfect nature of biometric feature extraction and matching algorithms. We elaborate on the suitability of these algorithms for digital rights management systems.     

Two new canonic single-CFOA oscillators with single resistor controls

Although a number of single current feedback op-amps (CFOA)-based single-resistance-controlled oscillators (SRCO) have appeared in earlier literature, only six of them are canonic (i.e., requiring only two capacitors and only three resistors). The object of this brief is to add to this list two new canonic single-CFOA-based SRCO configurations. An evaluation of these two new circuits has been carried out and their workability of has been confirmed by experimental results based upon AD844 CFOAs.     

An Effective Power-Aware At-Speed Test Methodology for IP Qualification and Characterization

Advanced nanometer technologies have led to a drastic increase in operational frequencies resulting in the performance of circuits becoming increasingly vulnerable to timing variations. The increasing process spread in advanced nanometer nodes poses considerable challenges in predicting post-fabrication silicon performance from timing models. Thus, there is a great need to qualify basic building structures on silicon in terms of critical parameters before they could be integrated within a complex System-on-Chip (SoC). The work of this paper presents a configurable circuit and an associated power-aware at-speed test methodology for the purpose of qualifying basic standard cells and complex IP structures to detect the presence of timing faults. Our design has been embedded within test-chips used for the development of the 28 nm Fully Depleted Silicon On Insulator (FD-SOI) technology node. The relevant silicon results and analysis validate the proposed power-aware test methodology for qualification and characterization of IPs and provide deeper insights for process improvements.     

Effect of linker used in D–A–π–A metal free dyes with different π-spacers for dye sensitized solar cells

Two novel D–A–π–A metal free dyes with triphenylamine as donor, dithiophene-diketo-pyrrolo-pyrrole as acceptor unit, thiophene and phenyl π-conjugated bridges and a cyanoacetic acid as electron acceptor (TDPP1 and TDPP2 were denoted for thiophene and phenyl π-conjugated bridge, respectively) have been designed and used as sensitizers for DSSCs. Incorporation of dithiophene-diketo-pyrrolo-pyrrole, reduces the band gap significantly. The influence of π-conjugated bridge on optical and electrochemical properties were investigated. Results demonstrated that the absorption band of TDPP with thiophene π-conjugated bridge has red shifted due to the enhancement of electron donating ability of π-conjugated bridge. The DSSC based on TDPP1 shows prominent power conversion efficiency about 4.81%, which is higher that for TDPP2 (3.42%). The electrochemical impedance spectroscopy analysis reveal that the charge recombination resistance at the TiO₂/dye/electrolyte interface for the DSSC based on TDPP1 is higher than that for TDPP2, which improves both J_sc and V_oc. The PCE of the DSSC based on TDPP1 is further improved up to 6.34%, when deoxycholic acid (DCA) was employed as coadsorbant.     

Binding of zinc to bovine and human milk proteins

Zn binding by whole bovine and human casein and by purified bovine caseins and whey proteins was investigated by equilibrium dialysis. Bovine alpha s1-casein had the greatest Zn-binding capacity (approximately 11 atoms Zn/mol). Protein aggregation was observed as Zn concentration was increased and the protein precipitated at a free Zn concentration of 1.7 mM. Zn binding increased with increasing pH in the range 5.4-7.0 and decreased with increasing ionic strength. Competition between Zn and Ca was observed for binding to alpha s1-casein indicating common binding sites for these two metals. Bovine beta-casein bound up to 8 atoms Zn/mol and precipitated at a free Zn concentration of approximately 2.5 mM, while kappa-casein bound 1-2 atoms Zn/mol. Whole bovine and human casein bound 5-8 atoms Zn/mol and precipitated at a free Zn concentration of approximately 2.0 mM. Scatchard plots for Zn binding to caseins showed upward convexity, possibly due to Zn-induced association of caseins. Apparent average association constants (Kapp) for all caseins were similar (log Kapp 3.0-3.2). Enzymic dephosphorylation of alpha s1- or whole bovine casein markedly reduced, but did not eliminate, Zn binding. Thus, phosphoserine residues appeared to be the primary Zn-binding sites in caseins. With the exception of bovine serum albumin, which bound over 8 atoms Zn/mol, the bovine whey proteins, beta-lactoglobulin, alpha-lactalbumin and lactotransferrin, had little capacity for Zn binding.     

Naltrexone blocks RFR‐induced DNA double strand breaks in rat brain cells

Previous research in our laboratory has shown that various effects of radiofrequency electromagnetic radiation (RFR) exposure on the nervous system are mediated by endogenous opioids in the brain. We have also found that acute exposure to RFR induced DNA strand breaks in brain cells of the rat. The present experiment was carried out to investigate whether endogenous opioids are also involved in RFRinduced DNA strand breaks. Rats were treated with the opioid antagonist naltrexone (1 mg/kg, IP) immediately before and after exposure to 2450 MHz pulsed (2 µs pulses, 500 pps) RFR at a power density of 2 mW/cm² (average whole body specific absorption rate of 1.2 W/kg) for 2 hours. DNA double strand breaks were assayed in brain cells at 4 hours after exposure using a microgel electrophoresis assay. Results showed that the RFR exposure significantly increased DNA double strand breaks in brain cells of the rat, and the effect was partially blocked by treatment with naltrexone. Thus, these data indicate that endogenous opioids play a mediating role in RFRinduced DNA strand breaks in brain cells of the rat.