795 research outputs found

    VIRTUAL REALITY SIMULATION FOR MYRINGOTOMY TRAINING WITH HAPTIC FEEDBACK

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    Myringotomy is a surgical procedure in which an incision is made in the eardrum, primarily to treat middle-ear infections. It is a difficult procedure for surgical residents to master because excellent hand-eye coordination is required to work under a surgical microscope and within the narrow ear canal. We have been developing a virtual-reality based surgical simulator for training residents. The current simulator does not include tactile feedback, but such feedback is a very important part of ear surgery. Therefore, the objectives of this work were to incorporate haptic feedback capability into our simulator, estimate the haptic parameter for the eardrum and perform a face validity study to test the effectiveness of the simulator. The results from the face validity study are very encouraging. The simulator is the first of its kind, and with further refinement has excellent potential to be of benefit in the training of proficient surgical residents

    Miniaturization of PCR Machine

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    The polymerase chain reaction (PCR) is a technique defined for copying specific DNA sequences. The three basic steps in that process - splitting a DNA template into its two single strands (called denaturation); adding short segments of complementary DNA called primers to initiate replication of a chosen DNA sequence (annealing); and adding DNA polymerase to synthesis the complementary strand (called extension) - are repeated again and again to amplify the sequence. Each of these steps occurs optimally at a different temperature, so heating and cooling is carried out with an instrument called a thermal cycler. Better than the conventional big size PCR here we have designed a circuit which is capable of performing fast temperature rise and fall and that is within small region. This design supports the easy transportability of the machine because of its smaller size with very low design cost

    Fabrication of micro separation column for miniaturized gas chromatography system

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    The emphasis of this work is on the fabrication of a micro separation column for applicaton in miniaturized gas chromatography system. The micro column was made by microchannels fabricated on the silicon wafer and sealed with a glass lid. The microchannels were fabricated by wet etching process and the channels were of length 2m , width 200 μm and depth 100 μm. The channels were closed by sealing with Pyrex glass. Silicide bonding was done for the bonding of silicon with Pyrex glass. Ti was used as an intermediate layer and bonded at a temperature of 377 ◦C and a force of 1kN. During bonding Ti forms an alloy with silicon and forms Titanium silicide and this helps to bond the glass wafer with silicom wafer with microchannels etched on it

    Interpretation of MPPT Techniques in Grid Connected Solar PV Array System

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    Solar energy is one of the most used and readily available renewable energy sources among the other energy sources. The power generated by PV systems is dependent on solar irradiance and temperature parameters. In the literature, many researchers and studies are interested in estimating true maximum efficiency point for the PV systems. Due to that fact, MPPT applications and techniques become an important issue for PV systems under both uniform and non uniform conditions. Although, PV system under uniform environment has only one maxima point on P-V curve which is simple to estimate correctly by conventional MPPT techniques, it is not as simple as under non-uniform condition such as partial shading and mismatch effects. To overcome the drawbacks of the conventional MPPTs under non uniform condition, researchers has been investigated new soft computing MPPTs, PV array configurations, system architectures and topologies

    Assessment of microbial diversity under arid plants by culture-dependent and culture-independent approaches

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    In this work, microbial community structure of two distinct arid plants like ker (Capparis deciduas) and pearl millet (Pennisetum glaucum) was assessed and defined by culture-dependent and cultureindependent approaches on the basis of 16S rRNA and random amplified polymorphic DNA (RAPD) analysis. The average Jaccard’s similarity coefficient values for cultivated bacteria that is within ker and pearl millet rhizosphere were 0.701 and 0.707, respectively, for non-rhizosphere of ker and pearl millet 0.739 and 0.762, respectively, and for non-cultivable bacteria under ker (0.519) and under pearl millet (0.534). Both culture- dependent and culture-independent methods indicated that in arid crops, microbial diversity is more influenced by soil type rather than plant type and lower Jaccard value for metagenome showed that whole community harbours more diversity because of different microflora than cultivated only. Salinity and temperature tolerance study of bacteria indicated that ker rhizosphere harbours more salinity and temperature tolerant bacteria.Keywords: Random amplified polymorphic DNA (RAPD), ribotyping, Thar Desert, microbial diversity, 16S rRNA.African Journal of Biotechnology Vol. 12(40), pp. 5860-586

    Measurement and modeling of pulsatile flow in microchannel

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    An experimental study of pulsatile flow in microchannel is reported in this paper. Such a study is important because time-varying flows are frequently encountered in microdevices. The hydraulic diameter of the microchannel is 144 μm and deionized water is the working fluid. The pressure drop across the microchannel as a function of time is recorded, from which the average and r.m.s. pressure drops are obtained. The experiments have been performed in the quasi-steady flow regime for a wide range of flow rate, frequency of pulsations, and duty cycle. The results suggest that the pressure with pulsations lies between the minimum and maximum steady state pressure values. The average pressure drop with pulsation is approximately linear with respect to the flow rate. The theoretical expression for pressure has also been derived wherever possible and the experimental data is found to lie below the corresponding theoretical values. The difference with respect to the theoretical value increases with an increase in frequency and a decrease in flow rate, with a maximum difference of 32.7%. This is attributed to the small size of the microchannel. An increase in frequency of square waveform leads to a larger reduction in pressure drop as compared to rectangular waveform, irrespective of the duty cycle. The results can be interpreted with the help of a first-order model proposed here; the model results are found to compare well against the experimental results. A correlation for friction factor in terms of the other non-dimensional governing parameters is also proposed. Experimental study of mass-driven pulsatile flow in microchannel is being conducted for the first time at these scales and the results are of both fundamental and practical importance

    Three-Dimensional Numerical Study of Conjugate Heat Transfer in Diverging Microchannel

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    Increase in applications of varying cross sectional area microchannels in microdevices has provided the need to understand fluid flow and heat transfer through such flow passages. This study focuses on conjugate heat transfer study through a diverging microchannel. Three-dimensional numerical simulations are performed using commercially available package. Diverging microchannels with different geometrical configurations (i.e. varying angle: 1-8°, depth: 86-200 μm, solid-to- fluid thickness ratio: 1.5-4) are employed for this purpose. Simulations are carried out for varying mass flow rate (3.3 x 10 –5 -8.3 x 10 –5 kg/s) and heat flux (2.4-9.6 W/cm 2 ) conditions. Heat distribution along the flow direction is studied to understand the effect of wall conduction. Wall conduction number ( M ) varies from 0.006 to 0.024 for the range of parameters selected in the study. Wall conduction is observed to be a direct function of depth and solid-to-fluid thickness ratio, and varies inversely with angle of diverging microchannel. It is observed that the area variation and wall conduction contribute separately towards redistribution of the supplied heat flux. This leads to reduced temperature gradients in diverging microchannel. The results presented in this work will be useful for designing future microdevices involving heating or coolin

    An open labeled study to evaluate efficacy and safety of ampucare in patients with bedsore

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    Background: To evaluate efficacy and safety of ampucare, a polyherbal product, in patients with bedsore.Methods: One hundred patients, either sex, more than 18 years of age, with bedsore were divided in to two groups of 50 each. Group-I- Served as control- povidone iodine solution was applied locally on the bedsore, once daily. Group- II- Treatment group- ampucare lotion was applied locally, once daily. Primary end point was time to wound healing and secondary end point included reduction in wound surface area at day-7 and at treatment completion. Percent patients cured, improved, or treatment failure were noted. Depth of wound, % healing and adverse effects were recorded.Results: Application of ampucare in patients with bedsore resulted in rapid healing as compared to control group. Reduction in wound surface area was significant (p<0.01) in group-II. Maximum gain in thickness of granular tissue was observed in this group. In treatment group 68% patients showed excellent response as compared to 60 % in control group. Ampucare was well tolerated.Conclusions: Ampucare treatment markedly accelerates wound healing in patients with bedsore

    Analysis of Impact of Transformer Coupled Input Matching on Concurrent Dual-Band Low Noise Amplifier

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    Emerging advancements in telecommunication system need robust radio devices which can capable of working multiple frequency bands seamlessly. In any Radio Frequency (RF) receiver architecture, Low Noise Amplifier (LNA) is the mandatory front-end part in which takes place in between antenna and mixer. To support multiple frequency bands with single hardware, concurrent LNA is the more preferred topologies among others. As LNA is the very front end level of receiver, Input matching, Noise Figure (NF) and gain are the major performance parameters to be concerned. In this work, the impact of transformer coupled input matching on concurrent dual-band LNA is analyzed and verified. A concurrent LNA with concurrent matching without transformer coupling is used for comparison. A transformer coupled input matching is proposed for tunable concurrent dual-band LNA. All the circuits are implemented in UMC 180nm CMOS technology, and simulated using Cadence SpectreRF simulation tool
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