Impact of Martensite Spatial Distribution on Quasi-Static and Dynamic Deformation Behavior of Dual-Phase Steel

The effects of microstructure parameters of dual-phase steels on tensile high strain dynamic deformation characteristic were examined in this study. Cold-rolled steel sheets were annealed using three different annealing process parameters to obtain three different dual-phase microstructures of varied ferrite and martensite phase fraction. The volume fraction of martensite obtained in two of the steels was near identical (~ 19 pct) with a subtle difference in its spatial distribution. In the first microstructure variant, martensite was mostly found to be situated at ferrite grain boundaries and in the second variant, in addition to at grain boundaries, in-grain martensite was also observed. The third microstructure was very different from the above two with respect to martensite volume fraction (~ 67 pct) and its morphology. In this case, martensite packets were surrounded by a three-dimensional ferrite network giving an appearance of core and shell type microstructure. All the three steels were tensile deformed at strain rates ranging from 2.7 × 10^?4 (quasi-static) to 650 s^?1 (dynamic range). Field-emission scanning electron microscope was used to characterize the starting as well as post-tensile deformed microstructures. Dual-phase steel consisting of small martensite volume fraction (~ 19 pct), irrespective of its spatial distribution, demonstrated high strain rate sensitivity and on the other hand, steel with large martensite volume fraction (~ 67 pct) displayed a very little strain rate sensitivity. Interestingly, total elongation was found to increase with increasing strain rate in the dynamic regime for steel with core–shell type of microstructure containing large martensite volume fraction. The observed enhancement in plasticity in dynamic regime was attributed to adiabatic heating of specimen. To understand the evolving damage mechanism, the fracture surface and the vicinity of fracture ends were studied in all the three dual-phase steels.     

The Role of a Natural Language Conversational Interface in Online Sales: A Case Study

This paper describes the evaluation of a natural language dialog-based navigation system (HappyAssistant) that helps users access e-commerce sites to find relevant information about products and services. The prototype system leverages technologies in natural language processing and human-computer interaction to create a faster and more intuitive way of interacting with websites, especially for less experienced users. The result of a comparative study shows that users prefer the natural language-enabled navigation two to one over the menu driven navigation. In addition, the study confirmed the efficiency of using natural language dialog in terms of the number of clicks and the amount of time required to obtain the relevant information. In the case study, as compared to the menu driven system, the average number of clicks used in the natural language system was reduced by 63.2% and the average time was reduced by 33.3%.     

Characterisation of honey produced from different fruit plants of northern India

Studies were carried out to determine the affect of different fruit plant sources viz., Litche chinensis (litchi), Citrus sinensis (sweet orange), Ziziphus mauritiana (ber) and Prunus persica (peach) on moisture content, pH, free acidity, reducing sugars and sucrose contents, fructose/glucose ratio, ash and proline content, invertase and diastase activities, hydroxymethylfurfural and mineral (sodium, potassium, iron, calcium, zinc, and copper) contents as well as on rheological properties of honey. The source of honey had a significant (P < 0.05) effect on moisture content, free acidity, reducing sugar, fructose/glucose ratio, hydroxymethylfurfural content, invertase and diastase activities, sucrose content, proline content, ash content, pH and mineral content. The honey from various sources exhibited Newtonian behaviour and the activation energy ranged from 63.63 to 81.48 kJ mol^?1. Pattern recognition methods such as principal component analysis andlinear discriminate analysis were performed to classify honey on the basis of physico‐chemical properties and mineral content. The variables proline, potassium and free acidity exhibited higher discrimination power.     

Heat Priming of Lentil (Lens culinaris Medik.) Seeds and Foliar Treatment with γ-Aminobutyric Acid (GABA), Confers Protection to Reproductive Function and Yield Traits under High-Temperature Stress Environments

Gradually increasing temperatures at global and local scales are causing heat stress for cool and summer-season food legumes, such as lentil (Lens culinaris Medik.), which is highly susceptible to heat stress, especially during its reproductive stages of development. Hence, suitable strategies are needed to develop heat tolerance in this legume. In the present study, we tested the effectiveness of heat priming (HPr; 6 h at 35 °C) the lentil seeds and a foliar treatment of γ-aminobutyric acid (GABA; 1 mM; applied twice at different times), singly or in combination (HPr+GABA), under heat stress (32/20 °C) in two heat-tolerant (HT; IG2507, IG3263) and two heat-sensitive (HS; IG2821, IG2849) genotypes to mitigate heat stress. The three treatments significantly reduced heat injury to leaves and flowers, particularly when applied in combination, including leaf damage assessed as membrane injury, cellular oxidizing ability, leaf water status, and stomatal conductance. The combined HPr+GABA treatment significantly improved the photosynthetic function, measured as photosynthetic efficiency, chlorophyll concentration, and sucrose synthesis; and significantly reduced the oxidative damage, which was associated with a marked up-regulation in the activities of enzymatic antioxidants. The combined treatment also facilitated the synthesis of osmolytes, such as proline and glycine betaine, by upregulating the expression of their biosynthesizing enzymes (pyrroline-5-carboxylate synthase; betaine aldehyde dehydrogenase) under heat stress. The HPr+GABA treatment caused a considerable enhancement in endogenous levels of GABA in leaves, more so in the two heat-sensitive genotypes. The reproductive function, measured as germination and viability of pollen grains, receptivity of stigma, and viability of ovules, was significantly improved with combined treatment, resulting in enhanced pod number (21–23% in HT and 35–38% in HS genotypes, compared to heat stress alone) and seed yield per plant (22–24% in HT and 37–40% in HS genotypes, in comparison to heat stress alone). The combined treatment (HPr+GABA) was more effective and pronounced in heat-sensitive than heat-tolerant genotypes for all the traits tested. This study offers a potential solution for tackling and protecting heat stress injury in lentil plants.     

‘SODEPT’ A Software for Design of Percolation Tank

Percolation tanks are widely used for increasing recharge of ground water resources. This has been used from centuries in arid and semi arid regions of India and is known by different indigenous name, viz. rapat, nadi etc. However not much work has been done on standardization of the design parameters of these tanks, and therefore most of the time, tanks are either over designed or under designed. The design parameters of the percolation tank and amount of water recharged to groundwater during different months depend upon area of catchment, hydrological cover complex characteristics of the catchment, rainfall characteristics of the area, evaporation loss and seepage rate of the tank bed. Since rainfall and evaporation are stochastic variables, their distribution should also be accounted for. Further the dimensions of the tank will vary with the level of probability of design. With this in view, a software has been developed for giving the design parameters of the percolation tank. The input data are long term daily rainfall and evaporation data, seepage rate of the tank bed which is a function of textural characteristics and hydraulic conductivity, area of catchment, hydrological complex characteristics defined by curve numbers, area available for construction of the tank (length and width) for excavated type of the percolation tank or width of the gully and slope of the drainage way for impounded type of the tank, and cost of the earthwork for different depths and lead. The output is capacity of the tank for most economic recharge per unit investment, total recharge during the year, recharge during monsoon and recharge during post monsoon months and expected storage level at the end of the monsoon.     

Adaptation techniques in wireless packet data services

Today's cellular systems are designed to achieve 90-95 percent coverage for voice users (i.e., the ratio of signal to interference plus noise must be above a design target over 90 to 95 percent of the cell area). This ensures that the desired data rate which achieves good voice quality can be provided “everywhere”. As a result, SINRs that are much larger than the target are achieved over a large portion of the cellular coverage area. For a packet data service, the larger SINR can be used to provide higher data rates by reducing coding or spreading and/or increasing the constellation density. It is straight-forward to see that cellular spectral efficiency (in terms of b/s/Hz/sector) can be increased by a factor of two or more if users with better links are served at higher data rates. Procedures that exploit this are already in place for all the major cellular standards in the world. In this article, we describe data rate adaptation procedures for CDMA (IS-95), wideband CDMA (cdma2000 and UMTS WCDMA), TDMA (IS-136), and GSM (GPRS and EDGE)     

Slip in Flow through Assemblages of Spherical Particles at Low to Moderate Reynolds Numbers

Effects of slip velocity and volume fraction of slip spheres on the momentum transfer characteristics of assemblages of slip spheres are numerically investigated. The fluid slip along the surface of the sphere is considered by Navier's linear slip model. The dimensionless governing continuity and momentum equations are solved using a semi‐implicit marker and cell method implemented on a staggered grid arrangement in spherical coordinates. The convection and viscous terms of momentum equations are discretized by means of the QUICK scheme and a second‐order central differencing scheme, respectively. The present numerical solver is benchmarked via grid independence and comparisons with the existing literature values. Results were obtained over a wide range of pertinent dimensionless numbers such as the Reynolds number, volume fraction of the dispersed phase, and dimensionless slip parameter.     

Design of a medium access control feedback mechanism for cellularTDMA packet data systems

Cellular packet data systems require medium access control (MAC) protocols that allow flexible resource allocation on both the uplink and the downlink. The overhead introduced for managing MAC functions should be minimized, and control fields should be well protected in order to provide robustness to channel errors. The IS-136 TDMA digital control channel specifies shared channel feedback (SCF) procedures and fields for managing uplink resources. However, the SCF mechanism is not well suited to long packet data transactions. We describe a simple and robust packet channel feedback (PCF) mechanism for an IS-136 based TDMA packet data channel by identifying the minimal set of functions and fields required to manage both contention access and reserved access. The proposed scheme has unambiguous state transitions and better performance under error conditions. The PCF scheme provides considerable flexibility in assigning bandwidth to multiple users, and allows the efficient scheduling of contention and reservation opportunities on each subchannel without wasted slots     

Development of diclofenac potassium gel from hydrophobically modified HPMC

An improved topical gel was developed which could allow fast release of drug and having appropriate organoleptic (texture) and rheological properties (viscosity). In vitro release of diclofenac potassium from hydrophobically modified hydroxypropyl methyl cellulose (hm-HPMC, 90L grade) based gels (F1, F2 and F3 at 1, 1.5 and 2 % (w/v) concentration, respectively) was compared with conventional hydrophilic hydroxypropyl methylcellulose (HPMC, 50 mPa s) based gels (F4 and F5 at 12 and 15 % (w/v) concentration, respectively). This study was performed in Franz diffusion cell using cellulose dialysis membrane. The hm-HPMC-based gels of higher viscosity release remarkable quantity of the drug in comparison to conventional hydrophilic HPMC-based gels of lower viscosity. So in the drug-release process polymer concentration is more important and a determinant factor compared to viscosity. Texture profile and viscosity of hm-HPMC-based gels were compared with a commercial gel and all the rheological data obtained from the experiments confirm the suitability of these hm-HPMC-based gels for use as a topical drug delivery system. In order to achieve percutaneous penetration of drug, permeation enhancers (n-octanol and propylene glycol) were added in hm-HPMC-based gels. Both enhancers have shown enhancement of drug penetration through rat skin. Propylene glycol at both lower concentration (2 %) and higher concentration (5 %) exhibited a greater increase in the permeation flux as well as more antinociceptive activity than formulations without enhancer or with n-octanol as enhancer.