A secure and provable multi-server authenticated key agreement for TMIS based on Amin et al. scheme

The security for Telecare Medicine Information Systems (TMIS) has been crucial for reliable dispensing of the medical services to patients at distant locations. Security and privacy element needs to be there for any physician or caregiver to make certain an appropriate diagnosis, medical treatment or any other exchange of critical information. In this connection, many relevant TMIS-based authentication schemes have been presented, however various forms of attacks and inefficiencies render these schemes inapplicable for a practical scenario. Lately, Amin et al. proposed a scheme based on a multi-server authentication for TMIS. However, the Amin et al., scheme has been found vulnerable to user and server impersonation attacks. We have proposed an improved model with higher performance and efficiency, as evident from the forthcoming sections. Besides, the scheme has been backed up by formal security analysis using BAN logic to ensure the resilience of the proposed scheme.     

小球藻抽脂残留物培养产气肠杆菌的制氢研究

为使高效产氢产气肠杆菌能够运用到实际生产中,探索并且优化以小球藻抽脂残留物的水解产物为底物的厌氧批次产氢发酵实验参数.采用中心组合设计,通过三次平行实验取得的数值,拟合得到反映温度、接种量和p H值与产氢量之间关系的多元二次回归模型,以产氢率为响应值,进行响应面分析.方差分析结果显示,该模型的显著性和可靠性较高,拟合效果良好.该模型预测出最佳产氢结果为54.22 m L/g小球藻抽脂残留物,产氢条件为温度37.55℃,接种量12.25%,p H值5.95.进行了厌氧批次发酵产氢验证实验,实际结果为小球藻抽脂残留物的产氢量为54.61 m L/g,与预测值十分接近,说明该模型能较好反应三因素对产氢量的影响.优化了高效产氢菌利用廉价底物发酵产氢的运行条件,为实现生产氢气的过程与有机废弃物无害化处理相耦合提供了新思路.     

Production, purification and thermal characterisation of invertase from a newly isolated Fusarium sp. under solid-state fermentation

Production of invertase employing a newly isolated Fusarium sp. under solid-state fermentation was optimised. Different process parameters were optimised. The maximum enzyme activity under optimum conditions was 47.23 ± 2.12 U gds⁻¹ with nitrogen additives. The enzyme was purified by ammonium sulphate precipitation, diethylaminoethyl cellulose ion-exchange chromatography and Sephadex gel filtration. This protocol gave 20.25-fold purification and 5.53% recovery. The optimum pH and temperature for activity were 5.0 and 50 °C. The K _m and V _max values for the enzyme were 8.33 m m and 21.48 μmol min⁻¹, respectively. A detailed kinetic study of thermal inactivation has been carried out. Enthalpy of activation (Δ H *) decreased when entropy (Δ S *) of activation increased at higher temperatures. Moreover, free energy of denaturation (Δ G *) increased at higher temperature making the enzyme thermally stable. A possible explanation for the thermal inactivation of invertase at higher temperatures is also discussed.     

Investigation of structural and electrochemical properties of Na2Mn2(SO4)3 cathode for sodium-ion batteries

Journal of Materials Science: Materials in Electronics - Electrode materials with the benefits of high working voltage, low cost, and environmental benign are needed for the realization of...     

Ni(II) biosorption by Cassia fistula (Golden Shower) biomass

Cassia fistula is a fast-growing, medium-sized, deciduous tree which is now widely cultivated worldwide as an ornamental tree for its beautiful showy yellow flowers. Methods are required to reuse fallen leaves, branches, stem bark and pods when they start getting all over lawn. This investigation studies the use of these non-useful parts of C. fistula as naturally occurring biosorbent for the batch removal of Ni(II) in a well stirred system under different experimental conditions. The data showed that the maximum pH (pHmax) for efficient sorption of Ni(II) was 6 at which evaluated biosorbent dosage, biosorbent particle size, initial concentrations of Ni(II) and sorption time were 0.1 g/100 mL, <0.255 mm, up to 200 mg/L and 720 min, respectively. The experimental results were analyzed in terms of Langmuir and Freundlich isotherms. The Langmuir isotherm model fitted well to data of Ni(II) biosorption by C. fistula biomass as compared to the model of Freundlich. The kinetic studies showed that the sorption rates could be described better by a second order expression than by a more commonly applied Lagergren equation. The magnitude of the Gibbs free energy values indicates spontaneous nature of the sorption process. The sorption ability of C. fistula biomass for Ni(II) removal tends to be in the order: leaves相似文献   

Multi field modeling of a microelectromechanical speaker system with electrostatic driving principle

The need for computer modeling tools capable of precisely simulating multi-field interactions is increasing. The accurate modeling of an electrostatically actuated Micro-Electro-Mechanical-Systems speaker results in a system of coupled partial differential equations (PDEs), describing the interactions between electrostatic, mechanical and acoustic fields. A finite element (FE) method is applied to solve the PDEs efficiently and accurately. In the first part of this paper, we present the driving technology of an electrostatic actuated Micro-Electro-Mechanical-Systems speaker, where the electrostatic mechanical coupling is realized with reduced order electro mechanical transducer elements. The electrostatic attracting force is derived from the capacity to gap relation of our device. In a second investigation, we focus on generation of the generated sound including open domain characteristics and propagation region optimization. The sound pressure level is computed with Kirchhoff Helmholtz integral as well as with FEM by using CFS++. We use the Kirchhoff Helmholtz model to characterize the interactions of multiple speaker cells in arrays and the FE tool for single speaker cell investigations. At the acoustic FE model, the focus is on mesh generation and optimization of the propagation region using non-conforming grids (Mortar FEM) and in addition at the boundary region to model open domain characteristics. We apply a recently developed perfectly matched layer technique, which allows us to truncate the acoustic propagation domain with open domain characteristics. Finally, we present an optimization method taking advantage of stress induced self-raising realized with various merged layers with different intrinsic pre-stress. The buckling back plate concept can be compared to bimetal characteristics.