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Research Question: Is the relative risk for the development of hypertension more among non vegetarians than lacto vegetarians? Objectives: To compare the arterial blood pressure between lacto vegetarian and non-vegetarian males of 30 years and above. Design: Cross sectional study. Setting: In two different areas of walled city of Delhi. Study Variables: Blood pressure. Statistical analysis: Quetelet Index, t-test, z-test, x2-test, Relative risk

A typical catalytic process has been demonstrated for the well-known piezoelectric material lead zirconate titanate (PbZT). An easy and economical smartphone-based system is used to quantify the piezocatalytic degradation of the rhodamine B (RhB) and methylene blue (MB) dyes. Colorimetry is used for determining the unknown concentrations of the dyes during the piezocatalytic degradation. The values using smartphone-based colorimetry were compared with those obtained with a conventional spectrophotometer. The values obtained with the smartphone and the spectrophotometer were in good agreement. Almost 86% of RhB and 73% of MB were degraded by the PbZT piezocatalyst in 90 min during sonication. [ABSTRACT FROM AUTHOR]

Current-voltage (J-V) characteristics of an organic bulk heterojunction solar cell have been modeled and compared with the measured characteristics of solar cell based on the blend of poly(3-hexylethiophene) (P3HT) and phenyl [6,6] C61 butyric acid methyl ester (PCBM). In an undoped organic double Schottky junction diode, for V

There is no signature of the trap filled limit voltage (VTFL) in the J-V characteristics of a sample containing exponentially distributed traps. We show that VTFL and the voltage at which V2 dependence sets in (VMott) can be determined accurately. These voltages are independent of the energy distributions of the traps and depend strongly on the trap density Hb. Contrary to the literature results, it turns out that VTFL is significantly smaller than the VMott. In a specific case with Hb=1.6×1018 cm-3 and for a 5% accuracy in the current the value of VMott is about 400 V whereas VTFL is 13.5 V. Universal J-V curves in reduced units are derived and plotted. The reduced value of VTFL is 0.5. These curves are valid for all organics and inorganic semiconductors and for all energy distributions of traps. It is shown mathematically that all J-V curves approached Mott’s V2 law asymptotically as V increases to infinity. To validate the theory, the experimental J-V curves in polycrystalline undoped and Al doped ZnO thin films are made. The experimental results show good agreement with the theory. In the undoped ZnO films the traps are exponentially distributed and the trap concentration is calculated to be 1.7×1017 cm-3. The trap distribution in Al doped ZnO films is found to be discrete at a single level with trap concentration of 8×1016 cm-3. [ABSTRACT FROM AUTHOR]

When the transport and Poisson equations are integrated a constant of integration C should be used. If the Schottky barrier ([lowercase_phi_synonym]B) between metal electrode and organic semiconductor is zero, the injected carrier density at the contact is equal to that at the Fermi surface of the metal and can be taken as infinity to a good approximation. In this case the constant of integration C becomes zero. But for most cathodes and anodes used in organic devices the Schottky barriers are not zero. In these cases the constant C comes out to be A[J/P(0)m], where the constant A depends on material parameters, m is a constant more than 1, J is the current density, and P(0)∝exp(-[lowercase_phi_synonym]B/kT) is the injected carrier density. Even for a small value of the Schottky barrier [lowercase_phi_synonym]B=0.12 eV, P(0) is reduced by two orders of magnitude. For this or smaller value of P(0), C plays an important role in determining the J-V characteristics. We report a theory of J-V characteristics for finite (nonzero) Schottky barriers. Even for small values of the Schottky barrier the results are strikingly different from the conventional theory based on zero barrier. As the barrier increases the deviation from the conventional theory becomes large. For very large values of C, J-V characteristics become Ohmic. We have fabricated ITO/PEDOT:PSS/MEH-PPV/Au diode and measured their J-V characteristics. The theory given in this paper agrees with the experimental data at different temperatures and different sample thicknesses. [ABSTRACT FROM AUTHOR]

The product development process involves tolerance specification on the individual component dimensions. The impact of tolerance specification on manufacturing cost has drawn the attention of product designers towards economic tolerance synthesis using various optimization techniques. Simultaneous selection of manufacturing processes or machines from amongst the alternatives for producing a toleranced feature have also been considered. The solution surface for such a problem becomes a combinatorial and multi-modal function involving several local minima. Application of a genetic algorithm to the solution of this advanced tolerancing problem, together with benchmarking with the exact global solution obtained using Lagrange's multiplier-based exhaustive search method, has been reported in an earlier paper by the authors. The proposed algorithm is quite simple and straightforward, and automatically takes care of the process selection constraints. Application of the genetic algorithm has been demonstrated on complex tolerancing problems such as those involving interrelated dimension chains, complex stack-up conditions and complex cost functions, etc., where the use of traditional optimization techniques is not recommended. [ABSTRACT FROM AUTHOR]

Tolerance design is one of the most critical aspects of product design and development process as it affects both the product's functional requirements and manufacturing cost. Unnecessarily tight tolerances lead to increased manufacturing cost, while loose tolerances may lead to malfunctioning of the product. Traditionally, this important phase of product development is accomplished intuitively to satisfy design constraints, based on handbooks' data and/or skill and experience of the designers. Tolerance design carried out in this manner does not necessarily lead to an optimum design. Research in this area indicates that, in general, tolerance design is carried out sequentially in two steps; (1) tolerance design in CAD to obtain design or functional tolerances and (2) tolerance design in CAPP to obtain manufacturing tolerances. Such a sequential approach to tolerance design suffers from several drawbacks, such as more time consumption, suboptimality and unhealthy working atmosphere. This paper reports on an integrated approach for simultaneous selection of design and manufacturing tolerances based on the minimization of the total manufacturing cost. The nonlinear multivariable optimization problem formulated in this manner may result in a noisy solution surface, which can effectively be solved with the help of a global optimization technique. A solution methodology using genetic algorithms and applying penalty function approach with proper normalization of the penalty terms for handling the constraints is proposed. The application of the proposed methodology is demonstrated on a simple mechanical assembly with different tolerance stack-up conditions. [ABSTRACT FROM AUTHOR]

The space charge limited currents J in conducting organic materials often show J∼V[sup m] (where m > 2) dependence on voltage V. Two models have been used extensively to understand this behavior. In one model, the mobility μ is assumed to be dependent on electric field F. In the other model, an exponential distribution of traps is assumed and the mobility is taken to be independent of field. In this model the influence of the high electric fields present in organic polymers has not been taken into account. We present a model to calculate the J(V) characteristics for single carrier organic polymers taking into account the change in the occupancy of the traps due to the high electrical fields present in these materials. We show that the field dependent trap occupancy (FDTO) model can effectively explain the current-voltage characteristics reported by several different groups. If the FDTO model is used, it is not necessary to use the two different models mentioned above. [ABSTRACT FROM AUTHOR]

We improve the trapping model of carrier transport in conducting polymers by integrating the coupled Poisson and continuity equations numerically. In the case of exponentially distributed traps calculated log J vs 1/T plots are straight lines indicating that the activation of carriers to the extended states can be described by one single activation energy, E[sub eff]. The improved trapping model agrees well with the recent experimental data at high temperatures (i.e., near room temperature). At low temperatures the trapping model does not work since the available thermal energy is not sufficient to ionize the traps. We use the hopping mobility model at low temperatures. The model explains the low-temperature J-V characteristics well. This mechanism of charge carrier transport is similar to that used for interpreting experiments on inorganic amorphous materials. [ABSTRACT FROM AUTHOR]

On annealing a boron implanted Si sample at ∼800 °C, boron in the tail of the implanted profile diffuses very fast, faster than the normal thermal diffusion by a factor 100 or more. After annealing for a sufficiently long time, the enhanced diffusion saturates. The enhanced diffusion is temporary, on annealing the sample a second time after saturation, enhanced diffusion does not occur. It is therefore designated as transient enhanced diffusion (TED). The high concentration peak of the implanted boron profile, which is electrically inactive, does not diffuse. TED makes it difficult to fabricate modern Si based devices, in particular TED produces the parasitic barriers which degrade the performance of the SiGe heterostructure bipolar transistors and TED can limit the fabrication of shallow junctions required for sub-100 nm complementary metal-oxide-semiconductor technology. The mechanisms of TED have been elucidated recently. A Si interstitial "kicks out" the substitutional boron atom to an interstitial position where it can diffuse easily. Alternatively the interstitials and boron atoms form highly mobile pairs. In both cases Si interstitials are required for the diffusion of boron. Therefore the enhanced boron diffusivity is proportional to the concentration of the excess Si interstitials. The interstitials are injected during implantation with Si or dopant ions. The interstitials are also injected during oxidation of the Si surface. Therefore the diffusivity increases temporarily in both cases. Even at relatively low annealing temperatures (∼800 °C) the mobility of the interstitials is high. The TED at this temperature lasts for more than 1 h. This large TED time can be explained by the presence of interstitial clusters and interstitial-boron clusters. The interstitial clusters are the {311} extended defects and dislocation loops. The precise structure of interstitial-boron clusters is not yet known though several models have been proposed.... [ABSTRACT FROM AUTHOR]