Rapid Steel Tooling Via Solid Freeform Fabrication

With increasing part complexity and requirements for long production runs, tooling has become an expensive process that requires long lead times to manufacture. This lengthens the amount oftime from "art to part". Rapid tooling via stereolithography (SLA), filled epoxies, etc. have been stopgap measures to produce limited prototyping runs from (10 to 500 parts). This gives poor dimensional analysis and does not allow for limited production runs of 1000+ parts. The method ofproducing prototype tooling with a powdered metal process has been developed that produces tooling with a hardness greater than 35 HRC and total shrinkage less than 0.5%. This tooling process manufactures production ready tooling that will perform extended cycle runs (100,000+). Manufacturing ofthis tooling takes 1 to 2 weeks and will compare favorably with production grade steel tooling. Originals drawn in 3D CAD can be used to prototype the master that will allow for the production ofthe rapid metal tool set. process starts with a rapid prototyped model made by whatever process is desired or a machined master. For this paper a Sander's Model Maker II® rapid prototyping machine was used to fabricate the model. After the model ofthe tool set is made, a silicone rubber negative is cast around that model. After the silicone rubber model is made, a heated slurry ofmetal powders and polymers is poured into the mold to create the green tool set. The tool set is left to cool, and then removed from the silicone rubber mold. The tool set is then debound and sintered to produce a final tool set with properties approaching hardened tool steel.Mechanical Engineerin

New Metric Based Algorithm for Test Vector Generation in VLSI Testing

A new algorithm for test-vector-generation (TVG) for combinational circuits has been presented for testing VLSI chips. This is done by defining a suitable metric or distance, in the space of all input vectors, between a vector and a set of vectors. The test vectors are generated by suitably maximising the above distance. Two different methods of maximising the distance are suggested. Performances of the two methods for different circuits are presented and compared with the random method of TVG. It was observed that method B is superior to the other two methods. Also, method A is slightly better than method R

Fuzzy Logic and VLSI Testing

A new application of Fuzzy logic (FL), in the context of test vector generation in VLSI testing is presented. Fuzzification of the threshold value simulation (TVS) approach and setting up of mathematical concepts are carried out in terms of a hierarchy of membership functions. The test-vectors are found by optimising a suitable membership function. The Fuzzy model besides giving a different mathematical basis, also helps in defining new and better optimising functions, thus provind its utility. The concepts outlined in this paper, though demonstrated on toy model of a circuit consisting of only AND gates, can easily be extended to circuits with other logic gates

Heavy Quarks Above the Top at the Tevatron

Recent developments in models with warped extra dimensions have opened new possibilities for vector-like quark studies at hadron colliders. These new vector-like quarks can mix sizably with light Standard Model quarks without violating low energy constraints. We perform a model-independent analysis to determine the Tevatron reach in the search for new quarks. We find that the Tevatron has great potential to observe such quarks via their electroweak single production due to their mixing with valence quarks. With 4 (8) fb-1 integrated luminosity, one may reach a 5\sigma statistical significance for a heavy quark of mass 580 (630) GeV if the heavy quark-Standard Model quark mixing parameter is order one.Comment: Version published in Phys. Rev. D; 19 pages, 4 figures; extended version including model building example; added Table

Addressing family planning needs among low-literate population in peri-urban areas of Delhi, India: a qualitative inquiry

Background: Since several decades, population control has remained one of the major challenges for India. Understanding family planning (FP) related knowledge and practices, especially among low-literate population groups is important for increasing the reach of FP services nearer to them, which is an essential step for population control as well as to prevent unwanted pregnancies.Methods: We conducted a cross-sectional, qualitative research study among low literate population in peri-urban areas of New Delhi, bordered with Uttar Pradesh (U.P.) state. We selected and interviewed 27 participants including married men and women in the age range 18-34 years using semi-structured interview schedules. The focus of inquiry was on fertility awareness; beliefs and practices related to menstruation, pregnancy and FP methods etc. and decision making about FP. The data were processed for thematic analysis.Results: The study revealed lack of basic scientific knowledge about fertility in this community which often resulted into unwanted pregnancies. This finding has major implications especially when the Government’s FP program is geared mainly towards sterilization and conventional spacing methods. The study further confirmed that traditional beliefs and practices like separating women during menstruation still prevail in many joint families, but less likely in the nuclear ones. There were mixed opinions about spacing methods. Husband was reported to be main decision maker in FP process in this male dominated society. Regarding sources of information on FP, women reported elder women, lady clinicians and peers whereas men reported only peers.Conclusions: This study points out various barriers for FP around which basic FP education for both men and women in this community need to be provided. The study will have implications for other parts of India which share the same socio-cultural milieu as this community

Parametrically controlling solitary wave dynamics in modified Kortweg-de Vries equation

We demonstrate the control of solitary wave dynamics of modified Kortweg-de Vries (MKdV) equation through the temporal variations of the distributed coefficients. This is explicated through exact cnoidal wave and localized soliton solutions of the MKdV equation with variable coefficients. The solitons can be accelerated and their propagation can be manipulated by suitable variations of the above parameters. In sharp contrast with nonlinear Schr\"{o}dinger equation, the soliton amplitude and widths are time independent.Comment: 4 pages, 5 eps figure

Upper Bounds on Lepton-number Violating Processes

We consider four lepton-number violating (\lv) processes: (a) neutrinoless double-beta decay (0\nu\beta\beta), (b) Delta L = 2 tau decays, (c) Delta L = 2 rare meson decays and (d) nuclear muon-positron conversion. In the absence of exotic \lv interactions, the rates for these processes are determined by effective neutrino masses _{\ell_1\ell_2}, which can be related to the sum of light neutrino masses, the neutrino mass-squared differences, the neutrino mixing angles, a Dirac phase and two Majorana phases. We sample the experimentally allowed ranges of _{\ell_1\ell_2} based on neutrino oscillation experiments as well as cosmological observations, and obtain a stringent upper bound _{\ell_1\ell_2} \lsim 0.14 eV. We then calculate the allowed ranges for _{\ell_1\ell_2} from the experimental rates of direct searches for the above Delta L = 2 processes. Comparing our calculated rates with the currently or soon available data, we find that only the $0\nu\beta\beta$ experiment may be able to probe _{ee} with a sensitivity comparable to the current bound. Muon-positron conversion is next in sensitivity, while the limits of direct searches for the other Delta L = 2 processes are several orders of magnitude weaker than the current bounds on _{\ell_1\ell_2}. Any positive signal in those direct searches would indicate new contributions to the \lv interactions beyond those from three light Majorana neutrinos.Comment: 20 pages, revtex4, 2 figures (5 files), Version published in Physical Review

Controlling pulse propagation in optical fibers through nonlinearity and dispersion management

In case of the nonlinear Schr\"odinger equation with designed group velocity dispersion, variable nonlinearity and gain/loss; we analytically demonstrate the phenomenon of chirp reversal crucial for pulse reproduction. Two different scenarios are exhibited, where the pulses experience identical dispersion profiles, but show entirely different propagation behavior. Exact expressions for dynamical quasi-solitons and soliton bound-states relevant for fiber communication are also exhibited.Comment: 4 pages, 5 eps figure

Classical particles with internal structure: a systematic analysis

A comprehensive analysis of theories of classical relativistic particles with internal structure, based on group theoretic and differential geometric methods, is presented. The lagrangian formulation of dynamics is used

Lactobacillus plantarum (VR1) isolated from an Ayurvedic medicine (Kutajarista) ameliorates in vitro cellular damage caused by Aeromonas veronii

<p>Abstract</p> <p>Background</p> <p><it>Lactobacillus plantarum </it>is considered as a safe and effective probiotic microorganism. Among various sources of isolation, traditionally fermented foods are considered to be rich in <it>Lactobacillus </it>spp., which can be exploited for their probiotic attribute. Antibacterial property of <it>L. plantarum </it>has been demonstrated against various enteric pathogens in both <it>in vitro </it>and <it>in vivo </it>systems. This study was aimed at characterizing <it>L. plantarum </it>isolated from Kutajarista, an ayurvedic fermented biomedicine, and assessing its antagonistic property against a common enteropathogen <it>Aeromonas veronii</it>.</p> <p>Results</p> <p>We report the isolation of <it>L. plantarum </it>(VR1) from Kutajarista, and efficacy of its cell free supernatant (CFS) in amelioration of cytotoxicity caused by <it>Aeromonas veronii</it>. On the part of probiotic attributes, VR1 was tolerant to pH 2, 0.3% bile salts and simulated gastric juice. Additionally, VR1 also exhibited adhesive property to human intestinal HT-29 cell line. Furthermore, CFS of VR1 was antibacterial to enteric pathogens like <it>Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli</it>, <it>Aeromonas veronii </it>and clinical isolates of <it>P. aeruginosa </it>and <it>E. coli</it>. Detailed study regarding the effect of VR1 CFS on <it>A. veronii </it>cytotoxicity showed a significant decrease in vacuole formation and detrimental cellular changes in Vero cells. On the other hand, <it>A. veronii </it>CFS caused disruption of tight junction proteins ZO-1 and actin in MDCK cell line, which was prevented by pre-incubation with CFS of VR1.</p> <p>Conclusions</p> <p>This is the first study to report isolation of <it>L. plantarum </it>(VR1) from Kutajarista and characterisation for its probiotic attributes. Our study demonstrates the antagonistic property of VR1 to <it>A. veronii </it>and effect of VR1 CFS in reduction of cellular damage caused by <it>A. veronii </it>in both Vero and MDCK cell lines.</p