Antioxidant and trypsin inhibition activity of dioscorin influenced by yam cultivars and eluent pH

The total antioxidant activity (TAA) and trypsin inhibition activity (TIA) of storage protein dioscorin from six yam cultivars (Dashan, Hualien No. 3, Keelung, Mingchien, Tainong No. 2, and Japanese yam) were demonstrated. Japanese yam had the highest TAA and the lowest calculated EC₅₀ at any purification stage. Following gel permeation, dioscorins purified from Hualien No. 3 and Japanese yam showed the highest TIA and lowest calculated IC₅₀. Dioscorin with higher TIA apparently possesses better TAA. The pIs of dioscorin from all yam species were in the range of 5.94–4.33 indicating acidic protein in nature. Results from isoelectric focusing chromatography showed regardless of species higher TIA for dioscorin eluted at lower pH.     

An efficient solution to a retrial queue for the performability evaluation of DHCP

The Dynamic Host Configuration Protocol (DHCP) is designed to provide an automatic mechanism for the allocation, configuration and management of IP addresses and TCP/IP protocol stack parameters of computers and devices in IP networks. The important feature of DHCP is a “dynamic allocation” mechanism, which assigns an IP address to a client for a limited period of time (called a lease time). Therefore, a previously allocated IP address can automatically be assigned to another host by a DHCP server upon the expiration of the lease time if a host does not renew the use of an allocated IP address.This paper proposes a retrial queueing model to approximate the performability of the DHCP dynamic allocation mechanism. An efficient computational algorithm is developed to calculate the steady state probabilities of a continuous time discrete state Markov process. A comparison of our approximate model with a detailed simulation model of the DHCP dynamic allocation mechanism shows an excellent agreement between the analytical and the simulation results. The impact of the lease time parameter on the performability of the DHCP dynamic allocation mechanism is also illustrated through a numerical study.     

Numerical analysis of the manipulated high performance catalyst layer design for polymer electrolyte membrane fuel cell

A two‐dimensional, multiphase, non‐isothermal numerical model was used to investigate the effect of the high performance catalyst layer (CL) design. Microstructure‐related parameters were studied on the basis of the agglomerate model assumption. A conventional CL design (uniform Pt/C composition, e.g., 40 wt%) was modified into two sub‐layers with two different Pt/C compositions (in this study, 40 and 80 wt%). The performance of sub‐layers with different CL designs is shown to be different. Simulation results show that substituting part of the Pt/C 40 wt% with Pt/C 80 wt% increases the cell performance. It was found that factors including proton conductivity, open circuit voltage, and sub‐layer thickness have a significant impact on overall cell performance. Different water distribution for different membrane electrode assembly designs was also observed in the simulation results. More liquid water accumulation inside the membrane electrode assembly is seen when the Pt/C 80 wt% sub‐layer is next to the gas diffusion layer. Finally, several key design parameters for the proposed high performance CL design including agglomerate radius, Nafion thin film thickness, and the Nafion volume fraction within the agglomerate in terms of CL fabrication were identified on the basis of our simulation results. Copyright © 2014 John Wiley & Sons, Ltd.     

余白的丰富性 鼎峰地产北京办公室

MARU MARU办公室是鼎峰地产(White Peak公司)位于北京CBD的总部,鼎峰地产是一家以不动产投资为主要方向的欧洲私募基金公司,2007年进入中国。MARU在日语里的意思是圆圈。整个办公室的平面比较规整,基本是一个正方形。这样的平面形式不需要设计师克服太多建筑上的缺陷,但是也使空间     

Adsorption properties of immobilized metal nanoparticles

The adsorption properties of the original TiO₂, MgO, and SiO₂ surfaces and those modified with nanoscale gold and nickel particles are studied using the dynamic sorption in a range of low coverages. N-alkanes (C₆–C₉) and adsorbate molecules with different donor and acceptor properties were taken as the reference compounds. Differential molar heats of adsorption of the adsorbates (Q _ν) are determined from the experimental retention data and, in the case of polar adsorbates, contributions from the dispersion and specific interactions to Q _ν are found. Donor and acceptor characteristics of the original and modified oxide surfaces are estimated. The immobilization of gold and nickel nanoparticles is shown to result in the formation of less active donor (K _D ) and acceptor (KA) sites compared to those on the original substrate surfaces. Changes in the surface chemistry and adsorption properties of Au/SiO₂ composites compared to the original substrate are less pronounced than in the case of Au,Ni/TiO₂ and Au,Ni/MgO composites.     

TEE EFFECT OF EXTENDED THIN FILM EVAPORATION DURING TEE CONSTANT DRYING RATE PERIOD

ABSTRACT

The extended thin film evaporation is analyzed during the constant drying rate period. The extended thin film is defined as the liquid film which the disjoining pressure dominates the fluid flow field and works as the driving force of replenishing the evaporating liquid. The results of the analysis show that the extended thin film evaporation can compensate the reduction of evaporation rate due to the increase of dry spots and keep the evaporation rate nearly constant. Experimental data in the literature are in good agreement with the results of this work. This implies that the extended thin film evaporation may be an important part of the mechanism for drying.     

Exhaust emissions control and engine parameters optimization using artificial neural network virtual sensors for a hydrogen-powered vehicle

This paper presents an alternative tool for vehicle tuning applications by incorporating the use of artificial neural network (ANN) virtual sensors for a hydrogen-powered car. The objective of this study is to optimize simple engine process parameters to regulate the exhaust emissions. The engine process parameters (throttle position, lambda, ignition advance and injection angle) and the exhaust emission variables (CO, CO₂, HC and NO_x) form the basis of the virtual sensors. Experimental data were first obtained through a comprehensive experimental and tuning procedure for neural network training and validation. The optimization layer-by-layer neural network was used to construct two ANN virtual sensors; the engine and emissions models. The performance and accuracy of the proposed virtual sensors were found to be acceptable with the maximum predictive mean relative errors of 0.65%. With its accurate predictive capability, the virtual sensors were then employed and simulated as a measurement tool for vehicle tuning and optimization. Simulation results showed that the exhaust emissions can be regulated by optimizing simple engine process parameters. This study presents an alternative tool for vehicle tuning applications for a hydrogen-powered vehicle. In addition, this work also provided a tool to better understand the effects of various engine conditions on the exhaust emissions without the need for any vehicle modifications.     

Design of “silent” circular saws

Abstract

This paper addresses a new problem of aligning two rows of movable terminals in order to minimize the channel width and via usage in the channel. The alignment problem of movable terminals is subject to the constraint that the number of vertical tracks used is not increased in the process. This constraint is not considerated in the paper referred to [6] which first considered the alignment problem of movable terminals. This problem is first shown to be NP‐complete, therefore, we present a heuristic algorithm. All examples presented in [2] including Deutsch's difficult example are used as the test routing problems. The programs were coded in C and implemented on SUN 3/110 workstation.     

INTEGRATED KNOWLEDGE ACQUISITION FROM TEXT,PREVIOUSLY SOLVED CASES,AND EXPERT MEMORIES

Within the model-based knowledge engineering framework, an integrated knowledge acquisition method was developed for a complex real-world domain with different traces of expertise. By having an expert constructively explain the previously solved cases with more general information from other traces of expertise ( text, expert memories) a model-centered knowledge base is constructed. The proposed method allows for an early knowledge verification where the relevance, sufficiency, redundancy, and consistency of knowledge are already assessed at an informal level The early knowledge verification efficiently prepares the consecutive knowledge formalization. Through a cognitively adequate model of expertise and the explanation-oriented knowledge elicitation procedures, user-friendly second-generation expert systems may be developed.