Full‐Textile Wireless Flexible Humidity Sensor for Human Physiological Monitoring

Textile‐based electronic techniques that can in real‐time and noncontact detect the respiration rate and respiratory arrest are highly desired for human health monitoring. Yarn‐shaped humidity sensor is fabricated based on a sensitive fiber with relatively high specific surface area and abnormal cross‐section. The response and recovery time of the yarn‐shaped humidity sensor is only 3.5 and 4 s, respectively, with little hysteresis, because of the hydrophobic property of these functional fibers and the grooves on the surface of the fibers, which is much faster than those of the commercial polyimide materials. Moreover, a battery‐free LC wireless testing system combined with the yarn‐shaped sensor is fabricated, which is further successfully imbedded into the intelligent mask to detect human breath. Based on the detection of LC wireless testing system, the frequency of 50.25 MHz under the exhaled condition shifts to 50.86 MHz under the inhaled situation of humidity sensor. In essence, the functional yarns with proper structure, would be an excellent candidature to the yarn‐shaped humidity sensor, in which there are good performance and wide application possibilities, eventually offering a facile method for the wireless detection of human physiological signals in the field of electronic fabrics.     

Analysis of soft handoff algorithm for multi‐cellular systems: A finite integral approach

In this paper the performance of soft handoff algorithm based on pilot signal strength measurements has been studied. In connection with the soft handoff it has been observed that the existing analytic expressions often involve integration in infinite limits. The expressions containing such kind of integrals have been meticulously transformed into finite range equations. Probability of outage, number of base stations (BS) in the active set, and number of active set updates are some of the performance metrics commonly considered in soft handoff. Accurate closed forms for all these performance indicators have been computed which, in turn, simplifies the calculation of several other metrics entailing them. Moreover, the underlying system model takes into account of more than two BS (specifically three) extending the traditional two BS model toward more complex but realistic characterization of soft handoff performance analysis framework. Copyright © 2009 John Wiley & Sons, Ltd.     

Organotin(IV) carboxylates of cyclopropane carboxylic acid and 3‐cyclohexylpropanoic acid: synthesis,characterization and biological activity. The crystal structure of bis(cyclopropanecarboxylato) tetramethyldistannoxane

A series of tri‐ and di‐organotin(IV) derivatives of the types R₃SnL, R₂SnL₂ and [(R₂SnL)₂O]₂ have been synthesized by the reaction of tri‐ and di‐organotin(IV) chloride(s) with sodium cyclopropane carboxylate and sodium 3‐cyclohexylpropanoate. Based on spectroscopic evidence (IR and NMR), all the triorganotin carboxylates were found to be penta‐coordinated in the solid state (except the tricyclohexyltin derivative, which was found to be four‐coordinated) and four‐coordinated in the solution state. Attempted reaction of Me₂SnCl₂ with sodium cyclopropane carboxylate in 1:2 stoichiometry afforded a bis(dicarboxylato tetraorganodistannoxane) complex, {[Me₂Sn(cyclo‐CH₂)₂CHCOO]₂O}₂. The X‐ray diffraction of this ‘dimethyltin(IV) complex’ shows that the compound possesses a tetranuclear aggregate with one bridging bidentate and other free organic ester type monodentate carboxylate groups in which each Sn atom has a five‐coordinated geometry. These complexes were also screened for their antifungal activities. Copyright © 2008 John Wiley & Sons, Ltd.     

On the state and guiding principles of broadband in india - [Topics in optical communications]

India, home to 1.2 billion people with a GDP growth of 9 percent, has been experiencing flat to modest growth of broadband services in the past decade despite the fact that the country continues to add 8?10 million cellular connections per month. In this article, we examine the reasons that affect the high cost of broadband in India and the steps required to reduce the cost. We also argue that the usage-based pricing model, which is used widely for billing retail customers, is hampering the growth of local content and services. In contrast, a flat-rate pricing model would spur demand for broadband services and enable content providers to target the local and emerging market. We study the Indian telecommunication scenario from a pricing and technology perspective to understand what the driving forces are for business to prosper. We then discuss the Indian landscape from a metro/access/core networks perspective. The technology choices and the methods of deployment are considered followed by an analysis of the service-centric model adopted by providers.     

A statistical approach to determine process parameter impact in Nd:YAG laser drilling of IN718 and Ti-6Al-4V sheets

The numerous unique advantages afforded by pulsed Nd:YAG laser systems have led to their increasing utility for producing high aspect ratio holes in a wide range of materials. Notwithstanding the growing industrial acceptance of the technique, the increasingly tighter geometrical tolerances and more stringent hole quality requirements of modern industrial components demand that “defects” such as taper, recast, spatter etc., in laser-drilled holes are minimized. Process parameters like pulse energy, pulse repetition rate, pulse duration, focal position, nozzle standoff, type of gas and gas pressure of the assist gas are known to significantly influence hole quality during laser drilling. The present study reports the use of Taguchi design of experiments technique to study the effects of the above process variables on the quality of the drilled holes and ascertain optimum processing conditions. Minimum taper in the drilled hole was considered as the desired target response. The entire study was conducted in three phases:(a) screening experiments, to identify process variables that critically influence taper in laser drilled holes, (b) Optimization experiments, to ascertain the set of parameters that would yield minimum taper and (c) validation trials, to assess the validity of the experimental procedures and results. Results indicate that laser drilling with focal position on the surface of the material being drilled and employing low level values of pulse duration and pulse energy represents the ideal conditions to achieve minimum taper in laser-drilled holes. Thorough assessment of results also reveals that the laser-drilling process, optimized considering taper in the drilled hole as the target response, leads to very significant improvements in respect of other hole quality attributes of interest such as spatter and recast as well.     

Surface preparation of Ti–3Al–2.5V alloy tubes for welding using a fiber laser

Ti–3Al–2.5V tubes are widely used in aircraft hydraulic systems. Meticulous surface preparation before welding is necessary to obtain a sound weld involving these alloy tubes. Conventionally this is done by cleaning with environmentally malign toxic chemicals, such as, hydrofluoric acid and nitric acid. This paper describes the laser-cleaning process of the surface of these tubes with a fiber laser as a preparation for pulsed gas tungsten arc welding and results obtained. A simple one-dimensional heat equation has been solved to evaluate the temperature profile of the irradiated surface. It is shown that surface preparation by laser cleaning can be an environmentally friendly alternative process by producing acceptable welds with laser-processed tubes.     

Mechanism and specificity of the terminal thioesterase domain from the erythromycin polyketide synthase

BACKGROUND: Polyketides are important compounds with antibiotic and anticancer activities. Several modular polyketide synthases (PKSs) contain a terminal thioesterase (TE) domain probably responsible for the release and concomitant cyclization of the fully processed polyketide chain. Because the TE domain influences qualitative aspects of product formation by engineered PKSs, its mechanism and specificity are of considerable interest. RESULTS: The TE domain of the 6-deoxyerythronolide B synthase was overexpressed in Escherichia coli. When tested against a set of N-acetyl cysteamine thioesters the TE domain did not act as a cyclase, but showed significant hydrolytic specificity towards substrates that mimic important features of its natural substrate. Also the overall rate of polyketide chain release was strongly enhanced by a covalent connection between the TE domain and the terminal PKS module (by as much as 100-fold compared with separate TE and PKS 'domains'). CONCLUSIONS: The inability of the TE domain alone to catalyze cyclization suggests that macrocycle formation results from the combined action of the TE domain and a PKS module. The chain-length and stereochemical preferences of the TE domain might be relevant in the design and engineered biosynthesis of certain novel polyketides. Our results also suggest that the TE domain might loop back to catalyze the release of polyketide chains from both terminal and pre-terminal modules, which may explain the ability of certain naturally occurring PKSs, such as the picromycin synthase, to generate both 12-membered and 14-membered macrolide antibiotics.     

Reduction of absorption loss in asymmetric twin waveguide laser tapers using argon plasma-enhanced quantum-well intermixing

Lasers based on asymmetric twin waveguide integration technology are limited by the necessity of pumping the tapers to avoid absorption losses within this section of the active region. Here, we demonstrate that the threshold current is reduced by argon plasma-enhanced quantum-well intermixing in the taper. Intermixing induces a (57/spl plusmn/5) nm wavelength blue shift in the emission peak, accompanied by a <12-nm linewidth broadening of the photoluminescence spectrum, indicating minimal material degradation. The threshold current of a 0.6-mm-long laser is reduced by (18/spl plusmn/1)% to (27/spl plusmn/1) mA using an intermixed taper as compared to a nonintermixed structure.     

Numerical computations of supersonic inlet flow

Air‐breathing propulsion systems for high‐speed space travel applications are studied. Ramjets and scramjets have been identified as potential candidates. The flow inlets of such systems are modelled with a simulation that can predict all complex inlet flow features, including shock due to forebody, multiple shock reflections, normal shock, shock–boundary layer interaction and associated separation for two‐dimensional and axisymmetric inlets. Computed values are in good agreement with experimental data. Copyright © 2001 John Wiley & Sons, Ltd.     

A review and assessment of hydrodynamic cavitation as a technology for the future

In the present work, the current status of the hydrodynamic cavitation reactors has been reviewed discussing the bubble dynamics analysis, optimum design considerations, design correlations for cavitational intensity (in terms of collapse pressure)/cavitational yield and different successful chemical synthesis applications clearly illustrating the utility of these types of reactors. The theoretical discussion based on the modeling of the bubble dynamics equations aims at understanding the design information related to the dependency of the cavitational intensity on the operating parameters and recommendations have been made for the choice of the optimized conditions of operating parameters. The design information based on the theoretical analysis has also been supported with some experimental illustrations concentrating on the chemical synthesis applications. Assessment of the hydrodynamic cavitation reactors and comparison with the sonochemical reactors has been done by citing the different industrially important reactions (oxidation of toluene, o-xylene, m-xylene, p-xylene, mesitylene, o-nitrotoluene, p-nitrotoluene, m-nitrotoluene, o-chlorotoluene and p-chlorotoulene, and trans-esterification reaction i.e., synthesis of bio-diesel). Some recommendations have also been made for the future work to be carried out as well as the choice of the operating conditions for realizing the dream of industrial scale applications of the cavitational reactors.