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Two-phase passive heat transport devices such as vapor chambers, loop heat pipes, and capillary pumped loops utilize porous evaporators for phase change and to drive fluid transport. Nucleate boiling can occur within such capillary-fed porous evaporators, especially under high-heat-flux operation, as has been visually observed in various experimental studies in the literature. However, prior modeling efforts have typically only considered single-phase flow of liquid through a completely saturated porous medium for characterizing the dryout limit and thermal performance. The present work offers a new semi-empirical model for prediction of thermal resistance and dryout during boiling in capillary-fed evaporators. Thermal conduction across the solid and volumetric evaporation within the pores are solved to obtain the temperature distribution in the porous structure. Capillary-driven lateral liquid flow from the outer periphery of the evaporator to its center, with vapor flow across the thickness, is considered to obtain the local liquid and vapor pressures. The capillary pressure and the relative permeabilities (fraction of single-phase permeabilities) for two-phase flow in the porous medium are modeled as a function of the local liquid saturation. The heat flux at which the liquid saturation at the center of the evaporator becomes zero is defined as the dryout limit of the evaporator. Experiments are conducted on sintered copper particle evaporators of different particle sizes and heater areas to collect data for model calibration. To demonstrate the wider applicability of the model for other types of porous evaporators, the model is further calibrated against a variety of dryout limit and thermal resistance data collected from the literature. The model is shown to predict the experimentally observed trends in the dryout limit with mean particle/pore size, heater size, and evaporator thicknesses.

Vapor chambers are being increasingly utilized as passive heat spreaders in various high-power density thermal management architectures. Particularly, in applications involving power electronics packaging, there is a need to understand and predict thermal performance of vapor chambers under different transient heat loads. It is known that boiling could occur in the wick structure of a vapor chamber at the location of heat input if sufficiently high heat fluxes are directly imposed on the chamber wall. Prior experimental studies that characterize the steady state thermal resistance of vapor chambers versus input power can only identify the behavior before and after the transition to boiling. However, because the initiation of boiling is a discrete event that occurs during the transient powering up, it is critical to understand how boiling behaviors will affect the performance of the vapor chamber in response to the transient heat input profile characteristics. Furthermore, currently available transient vapor chamber modeling efforts do not consider the occurrence of nucleate boiling, precluding their usage for applications where boiling is likely to occur. In this paper, we experimentally characterize the occurrence and effect of nucleate boiling in a vapor chamber coupled with an air-cooled heat sink, subject to various transient heat input profiles. The long-time step response behaviors are first studied for ten on-off cycles, at different on-powers, to illustrate the complete temperature response to a steady state in each cycle. For a range of intermediate powers, an interesting phenomenon is observed, where boiling occurs in every alternate cycle; we identify this range as the transition regime of boiling incipience in the vapor chamber. We further investigate the transient response to a pulsed heat input for various on-times ranging three orders of magnitude from 0.1 s to 400 s, and with two duty cycles (0.25 and 0.5), while keeping either the on-power or the average power constant. For a fixed on-power, lower on-times (0.1 s – 2 s) do not cause any boiling, but for longer on-times (≥ 20 s), cases with lower duty cycles led to occurrences of boiling incipience. Furthermore, for a fixed average power, a higher on-power at a lower duty cycle is more likely to cause boiling, which interestingly leads to an even lower mean steady temperature compared to cases with lower on-power and larger duty cycle. These studies provide insights into the nature of boiling incipience in vapor chambers for their usage under realistic transient input powers mimicking power electronics.

Background There is an estimation that globally 6 million people are dying due to cigarettes annually. Irrespective of the areas they live in i.e. urban and rural smoking became habitual in Indian population in many ways. By mid-2030 tobacco related deaths would rise to 10 million a year. Cigarette smoking affects respiratory function and is an obvious implication in the aetiology of various respiratory infections especially chronic bronchitis emphysema and bronchial carcinoma. This investigation was conducted to find out the lung function in smokers and non-smokers among college students.Objective To evaluate the respiratory functioning in smokers and non-smokers among college students.Method A samples of 50 students both male and females in the age group of 18 - 25 years fulfilling the inclusion criteria were selected for this case-control study.Outcome measure Lung function Questionnaire LFQ.Results The results show that the overall risk is less as the odds ratio from no risk upon. Risk is more than I but in case of smokers the risk is high.Conclusion The study concludes that there is a significant depletion of lung function in smokers in contrast to non-smokers.

Matrices are employed for diversified applications such as image processing, control systems, video processing, radar signal processing, compressive sensing and many more. Finding inverse of a floating point large scale matrix is considered to be computationally intensive and their hardware implementation is still a research topic. FPGA implementation of four different floating-point matrix inversion algorithms using a novel combination of high level language programming and model based design is proposed in this paper. The proposed designs can compute inverse of a floating point matrix up to a matrix size of 25×25 and can be easily scaled to large size matrices. The performance evaluation of proposed matrix inversion modules are carried out by their hardware implementation on a Zynq 7000 FPGA based ZED board and the results are reported.

Binary Phase Shift Keying (BPSK) is the most commonly used digital transmission technique for satellite telemetry link. FPGA implementation of BPSK demodulator for satellite telemetry link using model based programming is proposed in this paper. In order to evaluate the performance of proposed system, BPSK modulation scheme implemented on one FPGA board is fed as input to another FPGA board with BPSK demodulation scheme. Details about achieving frame synchronization in the demodulator board are reported and three approaches are proposed to reduce the Bit Error Rate (BER) of the system designed, which inturn enhances the frame retrieval accuracy. The performance evaluation is carried out using four combinations of data rate and carrier frequency, with the most commonly used two encoding schemes in satellites and ground station i.e., NRZ-L and NRZ-S. Zynq 7000 FPGA based ZED board is employed for the proposed work.

OBJECTIVES: The majority of people with suspected genetic dystonia remain undiagnosed after maximal investigation, implying that a number of causative genes have not yet been recognized. We aimed to investigate this paucity of diagnoses. METHODS: We undertook weighted burden analysis of whole-exome sequencing (WES) data from 138 individuals with unresolved generalized dystonia of suspected genetic etiology, followed by additional case-finding from international databases, first for the gene implicated by the burden analysis (VPS16), and then for other functionally related genes. Electron microscopy was performed on patient-derived cells. RESULTS: Analysis revealed a significant burden for VPS16 (Fisher's exact test p value, 6.9 × 109 ). VPS16 encodes a subunit of the homotypic fusion and vacuole protein sorting (HOPS) complex, which plays a key role in autophagosome-lysosome fusion. A total of 18 individuals harboring heterozygous loss-of-function VPS16 variants, and one with a microdeletion, were identified. These individuals experienced early onset progressive dystonia with predominant cervical, bulbar, orofacial, and upper limb involvement. Some patients had a more complex phenotype with additional neuropsychiatric and/or developmental comorbidities. We also identified biallelic loss-of-function variants in VPS41, another HOPS-complex encoding gene, in an individual with infantile-onset generalized dystonia. Electron microscopy of patient-derived lymphocytes and fibroblasts from both patients with VPS16 and VPS41 showed vacuolar abnormalities suggestive of impaired lysosomal function. INTERPRETATION: Our study strongly supports a role for HOPS complex dysfunction in the pathogenesis of dystonia, although variants in different subunits display different phenotypic and inheritance characteristics. ANN NEUROL 2020;88:867-877.

Binary Phase Shift Keying (BPSK) is the simplest and most commonly used digital transmission technique for satellite telemetry link. Design and evaluation of FPGA based BPSK demodulator using model based programming for satellite telemetry link is proposed is this paper. The system is designed using three approaches: Costas loop, square loop and comparator method. Two encoding schemes, NRZ-L and NRZ-S have been employed for the design. The performance of proposed design is evaluated by hardware implementation of the models on a Zynq 7000 FPGA based ZED board and the results are reported for various combinations of data rates and carrier frequencies.

Inverse of a matrix is considered as a computationally expensive matrix operation and design of floating point matrix inversion module for large matrices is still a research topic. In this paper, design and implementation of a floating-point matrix inversion module using model based design and novel architecture for FPGAs is proposed. The proposed module is designed to compute inverse up to a matrix size of 25×25 matrix and details about the scaling of proposed work for larger matrix sizes is also reported in the paper. The performance of proposed matrix inversion module is evaluated by its hardware implementation on a Zynq 7000 FPGA based ZED board and the results are reported.

Isoniazid forms one of the most potent antitubercular drugs effective against M. tuberculosis which functions in combination with pyrazinamide, rifampicin and ethambutol drugs. A drug is subjected to many complex processes from the time it is administered to the time the biologic response is affected. The physical properties give an idea of various types of interactions taking place between drug and water molecule. Keeping this in mind we have measured densities (ρ) and speeds of sound (u) of Isoniazid (INH) in aqueous, aqueous sodium chloride and potassium chloride (0.06 mol·kg−1 and 0.1 mol·kg−1 in water) at three different temperatures i.e. T = (288.15, 298.15 and 308.15) K in the concentration range of (0.01 to 0.1) mol·kg−1. From these experimental data, apparent molar volume ( V ϕ ) of solute, isentropic compressibility ( κ s ) of solution, apparent molar isentropic compressibility ( κ ϕ ) of Isoniazid (INH) in water and in aqueous solutions of 0.06 and 0.1 mol·kg−1 sodium chloride and potassium chloride have been calculated. The limiting apparent molar expansivity ( E ϕ 0 ) of solute and coefficient of thermal expansion ( α ∗ ) of Isoniazid (INH) have also been calculated. Transfer parameters have been interpreted from the point of view of concentration dependence of solute–solvent interactions. Infinite dilution values of V ϕ and κ ϕ have also obtained from extrapolation to zero molality and have been utilized in obtaining transfer volumes ( Δ tr V ϕ 0 ) and transfer compressibility ( Δ tr κ ϕ 0 ) of Isoniazid (INH) from aqueous solutions of 0.06 mol·kg−1 and 0.1 mol·kg−1 sodium chloride and potassium chloride at different temperatures. Results are used to analyze the nature of solute-solvent, solute-solute interaction and structure making/breaking ability of solute in the aqueous solution.

Drug interactions in presence of co-solute in aqueous solution have always created an interest in the mind of chemists. The physical properties give an idea of types of interactions taking place in aqueous solution. Volumetric and compressibility are the important physical properties. Keeping this in mind we have measured the densities ( ρ ) and speeds of sound ( u ) of sodium salicylate (NaSl) drug (0.01–0.1) mol·kg−1 in 0.06 mol·kg−1 aqueous sodium chloride solution and 0.06 mol·kg−1 myo-inositol as a function of temperature at T = (288.15, 298.15 and 308.15) K and atmospheric pressure. These values have been used to estimate the apparent molar volume of solute ( V ϕ ) , apparent molar isentropic compressibility ( κ s ) of solution and apparent molar isentropic compressibility ( κ ϕ ) of solute. The limiting apparent molar expansivity ( E ϕ 0 ) of solute and coefficient of thermal expansion ( α ∗ ) of sodium salicylate in aqueous binary and ternary solutions have also been obtained. Limiting values of apparent molar volume of solute ( V ϕ 0 ) and apparent molar compressibility of solute ( κ ϕ 0 ) were obtained from the plots V ϕ and κ ϕ as a function of molality and have been utilized in obtaining transfer volumes ( Δ tr V ϕ 0 ) and transfer compressibilities ( Δ tr κ ϕ 0 ) of sodium salicylate from water to 0.06 mol·kg−1 aqueous solutions of sodium chloride and myo-inositol at different temperatures. The co-sphere overlap model is used to interpret the values of ( Δ tr V ϕ 0 ) and ( Δ tr κ ϕ 0 ) . The Helper’s constant has been obtained. It indicates structure making ability of sodium salicylate in aqueous as well as in 0.06 mol·kg−1 aqueous sodium chloride and 0.06 mol·kg−1 aqueous myo-inositol solutions. The results obtained have been interpreted in terms of various interactions taking place among solute and solvent molecules.