Circular footings resting on geotextile-reinforced sand bed

The note pertains to an experimental study made on circular footings resting on semi-infinite layer of sand reinforced with geotextiles. Using the concept of homogenization of such soils, both analytical and numerical analyses have also been conducted to predict the load-settlement behavior and compared with experimental observations. The study highlights the effect of the footing size, number of reinforcing layers, reinforcement placement pattern and bond length and the relative density of the soil on the load-settlement characteristics of the footings.     

The magnitude of arsenic contamination in groundwater and its health effects to the inhabitants of the Jalangi--one of the 85 arsenic affected blocks in West Bengal, India

To better understand the magnitude of arsenic contamination in groundwater and its effects on human beings, a detailed study was carried out in Jalangi, one of the 85 arsenic affected blocks in West Bengal, India. Jalangi block is approximately 122 km2 in size and has a population of 215538. Of the 1916 water samples analyzed (about 31% of the total hand tubewells) from the Jalangi block, 77.8% were found to have arsenic above 10 microg l(-1) [the World Health Organization (WHO)-recommended level of arsenic in drinking water], 51% had arsenic above 50 microg l(-1) (the Indian standard of permissible limit of arsenic in drinking water) and 17% had arsenic at above 300 microg l(-1) (the concentration predicting overt arsenical skin lesions). From our preliminary medical screening, 1488 of the 7221 people examined in the 44 villages of Jalangi block exhibit definite arsenical skin lesions. An estimation of probable population that may suffer from arsenical skin lesions and cancer in the Jalangi block has been evaluated comparing along with international data. A total of 1600 biologic samples including hair, nail and urine have been analyzed from the affected villages of Jalangi block and on an average 88% of the biologic samples contain arsenic above the normal level. Thus, a vast population of the block may have arsenic body burden. Cases of Bowen's disease and cancer have been identified among adults who also show arsenical skin lesions and children in this block are also seriously affected. Obstetric examinations were also carried out in this block.     

Cracking Characteristics of RC Beams Strengthened with FRP System

The cracking characteristics of fiber-reinforced polymer (FRP) strengthened reinforced concrete (RC) beams in both the short- and long-term is addressed in this paper. First, an empirical equation based on regression analysis of test results obtained from 36 beams was derived for the evaluation of crack widths in FRP-strengthened RC beams under short-term loading. The equation accounts for the effective concrete area in tension, steel stress, proximity of tensile longitudinal reinforcement, and primary crack height. Next, the long-term crack widths of glass FRP-strengthened RC beams under sustained loads were studied. Beams strengthened with glass FRP laminates showed improved cracking characteristics with smaller crack widths compared to conventional RC beams. Based on the investigation, two empirical equations are presented to compute the long-term crack widths in FRP-strengthened beams.     

Low-Delay Parallel Architecture for Fractal Image Compression

This paper presents an efficient hardware architecture for implementing fractal image compression (FIC) algorithm aimed toward image compression with improved encoding speed. The proposed architecture follows the full-search-based FIC scheme. Parallel processing has been effectively used in the present work to achieve the goal of reducing the time complexity of the encoder. This architecture requires a total of \(2n+2\) clock cycles for executing the set of operations consisting of fetching the pixels, calculating the mean of range and domain blocks and doing their mapping, computing the error, and storing the fractal parameter in a memory with n number of pixels in the range block. Further, this architecture does not make use of any preprocessing operations as specified in literature and utilizes the benefits of isometric transformation without requiring additional cycles for every single matching operation. Effective application of isometric transformation has also led to memory reduction of nearly 67 %. Again, in the present work, the use of multipliers has been avoided to save the chip area, to reduce hardware complexity, and to enhance the encoding speed. The operation of transforming contracted domain block with a zero-mean domain block has facilitated relatively fast convergence at the decoder. PSNR above 30dB for a range block of size \(4\times 4\) has been achieved by the proposed architecture, which is comparable to that realizable by other architectures. The proposed design has been coded in Verilog HDL, has been implemented in Xilinx Virtex-5 FPGA, and operates at a clock frequency of 75.52 MHz.     

Ocular hazards of the colors used during the festival-of-colors (Holi) in India--malachite green toxicity

The objective of this study was to evaluate the nature of the colors used and their toxicity to the eye upon exposure to them during celebration of Holi (our festival-of-colors). Color powders and formulations were procured at random in and around Delhi during the festival. The green/bluish-green colors reported with the higher incidence of ocular toxicity were subjected for further evaluation. Eyewash fluid collected from the patients exposed to the colors was also subjected for analysis. This study was further extended to evaluate the corneal penetration of malachite green using goat cornea in perfusion chamber. In 16/18 color samples collected, malachite green or 4-[(4-dimethylaminophenyl)-phenyl-methyl]-N,N-dimethyl-aniline was detected at different concentrations. In the eyewash fluid of four patients, HPLC estimation confirmed the presence of malachite green at concentrations of 1.3, 0.18, 3.5 and 5.4 microg in 250 ml which was responsible for its reported toxicity. The in vitrotrans-corneal penetration studies did not show any detectable amount of malachite green in effluent fluid-in vitro tissue retention studies revealed that increasing the contact time increases tissue concentration. After 2 min of exposure, the tissue concentration was significantly higher. To conclude, malachite green was extensively used in our festival of Holi and has caused severe ocular irritation with epithelial defect upon exposure, though it did not penetrate through the cornea-further in vitro and in vivo studies are required on colors used in Holi.     

A [meso-tetrakis(4-sulfonatophenyl)porphyrinato]zinc(ii) complex as an oral therapeutic for the treatment of type 2 diabetic KKA(y) mice

We prepared and characterized [meso-tetrakis(4-sulfonatophenyl)porphyrinato]zinc(II) ([Zn(tpps)]), and investigated its in vitro insulin-mimetic activity and in vivo hypoglycemic effect in type 2 diabetic KKA(y) mice. The results were compared with those of previously proposed insulin-mimetic zinc(II) complexes and zinc sulfate (ZnSO(4)). The in vitro insulin-mimetic activity of [Zn(tpps)] was considerably better than that of bis(allixinato)zinc(II) ([Zn(alx)(2)]), bis(maltolato)zinc(II) ([Zn(mal)(2)]), bis(2-aminomethylpyridinato)zinc(II) ([Zn(2-ampy)(2)](2+)), and ZnSO(4). In particular, the order of in vitro insulin-mimetic activity of the complexes was determined to be: [Zn(tpps)]>[Zn(alx)(2)]>[Zn(mal)(2)]>[Zn(2-ampy)](2+)>ZnSO(4). [Zn(tpps)] normalized the hyperglycemia of KKA(y) mice within 21 days when administered orally at doses of 10-20 mg (0.15-0.31 mmol) Zn per kg body mass for 28 days. In addition, metabolic syndromes such as insulin resistance, the degree of renal disturbance, and the degree of liver disturbance were significantly improved in [Zn(tpps)]-treated KKA(y) mice relative to those administered with saline and ZnSO(4). The improvement in diabetes was validated by the results of oral glucose-tolerance tests and the decrease in the HbA(1c) level observed. In contrast, ZnSO(4) and the ligand H(2)tpps did not lower the elevated blood glucose level under the same experimental conditions. Based on these observations, [Zn(tpps)] is proposed to be the first orally active zinc(II)-porphyrin complex for the efficacious treatment of not only type 2 diabetes but also metabolic syndromes in animals.     

Cation exchange resin-catalysed esterification of acetic acid with 2-(1-cyclohexenyl)cyclohexanone

Self-aldol condensation of cyclohexanone yields a mixture of 2-(1-cyclohexenyl)cyclohexanone (I), 2-cyclohexylidenecyclohexanone (II) and subsequent condensation products. An acid-treated clay catalyst was employed to selectively obtain the β γ-unsaturated ketone (I). (I) was separated from the reaction mixture by fractional vacuum distillation and subsequently esterified with acetic acid to synthesise the corresponding ester, 2-(2-cyclohexyl acetate)cyclohexanone, a precursor of [1,1-biphenyl]-2,2'-diol, which has applications in plasticizers, pesticides, as a diluent in epoxy resins, etc. The applicability of cation exchange resins and an acid-treated clay for the esterification of 2-(1-cyclohexenyl)cyclohexanone with acetic acid was explored. This revised version was published online in July 2006 with corrections to the Cover Date.     

Scaling analysis and numerical simulation of natural convection from a duct

Natural convection from a duct into the quiescent ambient is investigated. Heat transfer and dynamics of natural convection from the duct are discussed using a simple scaling analysis and the corresponding scaling relations are obtained. Additionally, numerical simulation for a wide range of Rayleigh numbers from 10⁰ to 10⁶ and the duct aspect ratios from 0 to 4 with the Prandtl number of 0.71 (air) is performed. The development of natural convection may approach a steady or an unsteady state in a fully developed stage, which is determined by the Rayleigh number and the duct aspect ratio. It is demonstrated that heat transfer of natural convection is improved by the duct for high Rayleigh numbers but depressed for low Rayleigh numbers. The scaling relations of natural convection from the duct have been validated in comparison with numerical results. The scaling predictions are consistent with the numerical results. Furthermore, the formulae of the Nusselt number, the Reynolds number, and the flow rate quantifying natural convection from the duct are presented.     

TBHP-Mediated Intermolecular Radical Coupling and Intramolecular Cyclization Cascade: Access to Furo[2,3-b]quinoxalines and Their Photophysical Study

A cascade one-pot strategy to construct 31 examples of furo-fused quinoxalines in up to 88% yields has been devised from readily accessible β-ketothioamides and quinoxalin-2-ones in open flask at room temperature under TBHP mediated conditions. Mechanistic studies revealed that the overall reactivity relies on the seamless integration of intermolecular radical coupling and intramolecular cyclization via desulfhydration of C=S bond cleavage. Generation of H₂S as the only by-product makes this process highly attractive. Furthermore, the photophysical behavior of the furo-fused quinoxalines has also been studied.     

Stress-relaxation behavior of unidirectional polyethylene–carbon fibers: PMMA hybrid composite laminates

Unidirectional composite laminates based on carbon fibers (CF) and high-performance polyethylene fibers (PEF) and their hybrids were prepared with partially polymerized methyl methacrylate (MMA) at room temperature, followed by heating at 55°C (well below the softening point of PEF, 147°C) for 2 h. The stress-relaxation behavior of the composites were determined and analyzed. It was found that at all strain levels the rate of stress relaxation decreased by the loading of CF in CF-reinforced composite laminates (CFRC); however, the reverse behavior was found in the case of PEF-reinforced composite laminate (PEFRC). An interesting observation of the study was that the rate of stress relaxation decreased linearly in two steps in the case of PEFRC, whereas in the case of CFRC, it decreased in a single step. In the case of hybrid composites, the stress relaxation decreases in two steps as in PEFRC. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67:1925–1929, 1998