Comparative Moisture Performance of Wood/Wood-Based Claddings Predicted by Four Hygrothermal Simulation Tools

A number of hygrothermal(HAM)numerical simulation packages are available,either wholly or partially dedicated to heat,air and moisture transfer simulations of building materials and wall assemblies.The objective of this work was to compare the HAM responses and moisture performance of western red cedar and composite wood claddings of a wood frame wall as predicted by four HAM simulation tools:DELPHIN,WUFI,hygIRC,and COMSOL.Three Canadian cities having different climates were selected for simulation:Ottawa(ON),Vancouver(BC)and Calgary(AB).In each city,simulations were run for two years as selected from a historical climate data set based on the moisture index(MI).The wall orientation receiving the most wind-driven rain for the two years was selected for simulations.Material properties were taken from the National Research Council(NRC)material property database.Cladding temperature and relative humidity(RH)values as well as the moisture accumulated in the entire structure were compared amongst the results obtained from the four tools.The mold growth index on the cladding surface was used as a basis for comparing the moisture performance.

Experimental Investigation and Numerical Simulation on Interfacial Carbon Diffusion of Diamond Tool and Ferrous Metals

We numerically simulated and experimentally studied the interfacialcarbon diffusion between diamond tooland workpiece materials.A diffusion modelwith respect to carbon atoms of diamond toolpenetrating into chips and machined surface was established.The numericalsimulation results of the diffusion process revealthat the distribution laws of carbon atoms concentration have a close relationship with the diffusion distance,the diffusion time,and the originalcarbon concentration of the work material.In addition,diamond face cutting tests of die steels with different carbon content are conducted at different depth of cuts and feed rates to verify the previous simulation results.The micro-morphology of the chips is detected by scanning electron microscopy.Energy dispersive X-ray analysis was proposed to investigate the change in carbon content of the chips surface.The experimentalresults of this work are of benefit to a better understanding on the diffusion wear mechanism in single crystaldiamond cutting of ferrous metals.Moreover,the experimentalresults show that the diffusion wear of diamond could be reduced markedly by applying ultrasonic vibration to the cutting toolcompared with conventionalturning.

PVLab, a Powerful, Innovative Software Package for the Simulation of Photovoltaic Systems

This paper describes a new, highly modular, simulation tool named ＂PVLab＂ and developed by the GREMAN laboratory. It is designed to assist the designer in the sizing ofPV （photovoltaic） installations. The programming structure and physical models implemented within this tool are described, and several case studies are proposed to highlight its relevance. The predicted yearly electrical energy production of grid-connected PV plants is discussed. In particular, the predicted performance of such plants is compared with that given by the PVsyst software. PVLab has a high level of flexibility, allowing its physical models and databases （e.g., meteorological data） to be modified according to the user＇s needs. This is made possible through the use of expertise applied to all of the computing steps, and to the MATLAB development environment. The user＇s ability to control the source code itself will allow much greater progress to be made in the field of renewable energy applications than with PVsyst, which is currently the commercial reference.

Technology Provides Better Document Search Results on Slovak Legislation Webpage as Result of a Simulation of Webpage Performance Parameters

This article acquaints the public with the insights gained from conducting document searches in the Slovak public administration information system,when supported by knowledge of its management.Additionally,it discusses the advantages of simulating performance parameters and comparing the obtained results with the real parameters of the eZbierka(eCollection)legislation webpage.This comparison was based upon simulated results,obtained through the Gatling simulation tool,versus those obtained from measuring the properties of the public administration legislation webpage.Both sets of data(simulated and real),were generated via the the document search technologies in place on the eZbierka legislation webpage.The webpage provides users with binding laws and bylaws available in an electronically signed PDF file format.It is free open source.In order to simulate the accessing of documents on the webpage,the Gatling simulation tool was used.This tool simulated the activity,performed in the background of the information system,as a user attempted to read the data via the steps mentioned in the scenario.The settings of the simulated environment corresponded as much as possible to the hardware parameters and network infrastructure properties used for the operation of the respective information system.Based on this data,through load changing,we determined the number of users,the response time to queries,and their number;these parameters define the throughput of the server of the legislation webpage.The required parameter determination and performance of search technology operations are confirmed by a suitable hardware design and the webpage property parameter settings.We used the data from the eZbierka legislation webpage from its operational period of January 2016 to January 2019 for comparison,and analysed the relevant data to determine the parameter values of the legislation webpage of the slov-lex information system.The basic elements of the design solution include the technology used,the technology for searching the legislative documents with support of a searching tool,and a graphic database interface.By comparing the results,their dependencies,and proportionality,it is possible to ascertain the proper determination and appropriate applied search technology for selection of documents.Further,the graphic interface of the real web database was confirmed.

Distributed Generation Islanding Effect on Distribution Networks and End User Loads Using the Master-Slave Islanding Method

This study aims to address the feasibility of planned islanding operation and to investigate the effect of unplanned islanding using the master-slave islanding method for controlling the distributed generation units during grid-connected and islanding operation. Neplan desktop power simulation tool was used for the modelling and simulation of a realistic MV network with four different distributed generation technologies (diesel, gas, hydro and wind) along with their excitation and governor control systems, while an exponential model was used to represent the loads in the network. The dynamic and steady state behavior of the four distributed generation technologies were investigated during grid-connected operation and two transition modes to the islanding situation, planned and unplanned. The obtained results that validated through various case studies have shown that a suitable planned islanding transition could provide support to critical loads at the event of electricity utility outages.

WEB-BASED VIRTUAL CNC MACHINE MODELING AND OPERATION

A CNC simulation system based on intemet for operation training of manufacturing facility and manufacturing process simulation is proposed. Firstly, the system framework and a rapid modeling method of CNC machine tool are studied under the virtual environment based on PolyTrans and CAD software. Then, a new method is proposed to enhance and expand the interactive ability of virtual reality modeling language（VRML） by attaining communication among VRML, JavaApplet, JavaScript and Html so as to realize the virtual operation for CNC machine tool. Moreover, the algorithm of material removed simulation based on VRML Z-map is presented. The advantages of this algorithm include less memory requirement and much higher computation. Lastly, the CNC milling machine is taken as an illustrative example for the prototype development in order to validate the feasibility of the proposed approach.

Analytical Solution and Numerical Simulation of Real-Time Dispersion Monitoring Using Tone Subcarrier

A method for online dispersion monitoring by adding a single in-band subcarrier tone isintroduced.According to the theoretical analysis,the dispersion monitor and measurement range aredetermined by the specific frequency of the subcarrier tone.By using simulation tools,figures aboutrelationship between power of subcarrier tone and transmission distance in ideal condition are shown.