scholarly journals Troweling of Concrete Surfaces – Contemporary Methods

2019 ◽  
Author(s):  
Izabela Major ◽  
Jarosław Kalinowski
Keyword(s):  
Rotational Velocity ◽  
Simulation Method ◽  
Kinematic Parameters ◽  
Quantitative Parameter ◽  
Surface Machining ◽  
Working Element ◽  
Solid Disc ◽  
Analytical Formulas ◽  
Optimization Of Geometry

The paper presents an analysis of the process of troweling concrete surfaces using the disc power trowel machines. The quantitative parameter of the disc effect of the disc is its geometric efficiency Sg . The algorithm for calculation of geometric efficiency Sg by simulation method is presented. The analytical formulas for calculation of geometric efficiency Sg for the solid disc and the ring for uniform linear motion at constant rotational velocity are presented.The possibility of converting geometry of the working element to approximate geometry (in terms of geometric efficiency) with the form of concentric rings with center in the middle of the rotation of the disc is presented. The size of the ring was determined by a parameter called the filling factor w. This record allows to calculate the value of the geometric efficiency of the disc's effect by the analytical method as the sum of the geometric efficiency of all. The methodology of numerical calculation of the widths of overlapping of machining areas for neighboring disc tracks has been presented to ensure the highest homogeneity of machining. The adopted objective function to optimize the uniformity of machining is to minimize the index of standard deviation of the geometric efficiency εSg . The geometry of the real working elements most often used for troweling in the aspect of uniformity of machining was analyzed. The method of the optimization of geometry with the assumed kinematic parameters was indicated in order to obtain the best quality of surface machining.

scholarly journals Modelling the effect of continuous mixer operating parameters on mixture quality

2020 ◽  
Vol 164 ◽  
pp. 08009
Author(s):  
Alexey Kaliganov ◽  
Vladimir Konovalov ◽  
Alexey Chupshev ◽  
Vyacheslav Teryushkov
Keyword(s):  
Regression Model ◽  
Research Methodology ◽  
Coefficient Of Variation ◽  
Experimental Studies ◽  
Rotation Frequency ◽  
Operating Parameters ◽  
Kinematic Parameters ◽  
Continuous Mixing ◽  
Working Element

The aim of the research was to obtain a regression model of the influence of some structural and kinematic parameters of a continuous mixer working element on the quality of the prepared mixture. The research methodology included the analysis of the design of the mixing unit and the identification of factors that could significantly affect the quality of the mixture. Later, on the basis of the experimental studies, the quality of the mixture at given values of factors was determined and a regression model was established. The developed functional diagram of a continuous mixing unit made it possible to establish factors that most intensively affected the quality of the prepared mixture. The obtained adequate regression model of the coefficient of variation of the content of the control component in the samples of the mixture indicated an improvement in the quality of the mixture with an increase in the frequency of rotation of the mixers and the number of the arms levels. In terms of quality indicators, a rotation frequency of about 1500 rpm was most preferable with a number of mixer levels of at least 5.

scholarly journals Application of geoinformation techniques to determine zones of sediment resuspension induced by wind waves in lakes (using two lakes from Northern Poland as examples)

2016 ◽  
Vol 16 (1) ◽  
pp. 3-14
Author(s):  
Elżbieta Bajkiewicz-Grabowska ◽  
Maciej Markowski ◽  
Krzysztof Lemańczyk
Keyword(s):  
Lake Water ◽  
Wind Waves ◽  
Sediment Resuspension ◽  
Simulation Method ◽  
Northern Poland ◽  
Gis Tools

Abstract Resuspension in lakes affects the quality of lake water. It is possible to model this process and visualize its outcomes using GIS tools. An assessment of the size of the zone of sediment resuspension was made for two lakes located in Northern Poland threatened by rapid eutrophication. For each of the lakes, four simulations using two methods for determining the effective wind length (F) (Model 1 and Model 2) and two methods for determining the wind wavelength (Lw) (Model A and Model B) were performed. The analysis, taking into account the morphometry of the studied lakes and anemometric conditions, indicated that the differentiator is the applied simulation method of calculating the wavelength caused by the wind. The analysis is theoretical in nature and the results need to be verified in the field..

scholarly journals Traction control and diagnostics of electric and unmanned vehicles on roller stands

2020 ◽  
Vol 157 ◽  
pp. 01021
Author(s):  
Alexander Fedotov ◽  
Oleg Yankov ◽  
Anton Chernyshkov
Keyword(s):  
Electric Vehicles ◽  
Technical Condition ◽  
Test Methods ◽  
Unmanned Vehicles ◽  
Kinematic Parameters ◽  
Modes Of Operation ◽  
Traction Control ◽  
Wheeled Vehicles

The authors of the article analyze the possibilities of correct diagnostics of unmanned and electric vehicles on modern power and inertia roller stands. The purpose of this work is to improve the quality of monitoring the technical condition of wheeled vehicles by providing highly informative and stable test modes of operation in the process of their diagnostics. To achieve this target, we have developed test methods for wheeled vehicles, the implementation of which it is proposed to use a hybrid designed stand allows to measure force and power to the drive wheels of the vehicle, and temporal and kinematic parameters of the process of its functioning. The study proved that, to ensure a highly stable and test modes of operation of wheeled vehicles in the process of control of technical condition and diagnosis, you should use hybrid stands.

Influences of Ultrasonic Assistance in High Speed Lapping of Nano ZTA Engineering Ceramic on the Surface Machining Quality

2007 ◽  
Vol 359-360 ◽  
pp. 355-359 ◽  
Author(s):  
Feng Jiao ◽  
Bo Zhao ◽  
Chuan Shao Liu ◽  
Xun Sheng Zhu
Keyword(s):  
High Speed ◽  
Chip Thickness ◽  
Surface Profile ◽  
Abrasive Material ◽  
Regular Surface ◽  
Surface Machining ◽  
Machining Quality ◽  
Engineering Ceramic ◽  
Precision Finishing

Ultrasonic aided high speed lapping with solid abrasive material was put forward aimed at the precision finishing of nano ZTA engineering ceramic. Through theoretical analysis and contrast lapping experiments, the influences of ultrasonic assistance on the surface machining quality were clarified. Research results show that the maximum undeformed chip thickness in ultrasonic aided lapping is smaller than that in conventional lapping under the same conditions; ultrasonic assistance is beneficial to enlarging the range of ductile lapping regime and improving the surface quality of nano ZTA ceramic; with the application of ultrasonic vibration, smaller surface roughness and more regular surface profile can be obtained.

scholarly journals Study of the Influence of Helical Milling Parameters on the Quality of Holes in the UNS R56400 Alloy

2020 ◽  
Vol 10 (3) ◽  
pp. 845 ◽  
Author(s):  
Francisco Javier Puerta-Morales ◽  
Jorge Salguero Gomez ◽  
Severo Raul Fernandez-Vidal
Keyword(s):  
Titanium Alloy ◽  
Relevant Information ◽  
Helical Milling ◽  
Future Research ◽  
Kinematic Parameters ◽  
Hole Quality ◽  
Milling Parameters ◽  
Preliminary Study ◽  
Conventional Drilling

Helical milling has been positioned as an alternative to conventional drilling, where the advantages it offers make it very attractive for use on difficult-to-machine alloys such as the titanium alloy UNS R56400. However, the correlation between the indicator of hole quality and the kinematic parameters has rarely been studied. The kinematics are what bring most advantages and that is why it is necessary to know their influence. In this aspect, there are different focuses of problems associated with the complexity of the process kinematics, which makes it necessary to undertake a deeper analysis of the process and to carry out a preliminary study. To address this problem, a DOE (Design of Experiments) is proposed to identify the sensitivity and the main trends of the properties that define the quality holes with respect to the kinematic parameters. At the same time, a nomenclature is proposed to unify and avoid misinterpretations. This study has allowed us to obtain conclusive results that offer very relevant information for future research

Application of Transfer Functions to the Thermal Processing of Sweet and Sour Cherries Preserves: Influence of Particle and Container Sizes

2003 ◽  
Vol 9 (2) ◽  
pp. 69-76 ◽  
Author(s):  
C. A. Márquez ◽  
V. O. Salvadori ◽  
R. H. Mascheroni ◽  
A. De Michelis
Keyword(s):  
Thermal Processing ◽  
Transfer Functions ◽  
Sucrose Solution ◽  
Simulation Method ◽  
Point Of View ◽  
Average Error ◽  
Transfer Function Method ◽  
Glass Containers ◽  
Enzyme Degradation

The conditions of thermal processing of fruit preserves packed in transparent glass containers have great importance from the point of view of the final product appearance. Process simulation can allow to predict the quality of the product and its possible degradation. This work applied the transfer function method to simulate the pasteurisation of whole sweet and sour cherries canned in glass containers, with a 25 °Brix sucrose solution as covering liquid, and the predicted results were experimentally tested. The influence of fruit and container diameters on the treatment times was analysed. Kinetic models for enzyme degradation were coupled to the prediction model as examples of the possibilities of optimising the whole pasteurisation process. The accuracy (average error in predicted temperatures: 2.1%) of the simulation method was satisfactory for practical purposes, its use resulted simple and fast, and it allowed adjusting of pasteurisation times, even during the process.

scholarly journals Effect of two freezing extenders on characteristic of fresh and frozen-thawed semen in endangered Old Kladruber stallions – A pilot study

2017 ◽  
Vol 62 (No. 6) ◽  
pp. 227-233 ◽  
Author(s):  
J. Šichtař ◽  
A. Nehasilová ◽  
O. Šimoník ◽  
F. Bubeníčková
Keyword(s):  
Egg Yolk ◽  
Quality Parameters ◽  
Computer Assisted ◽  
Kinematic Parameters ◽  
Fluorescence Staining ◽  
Sperm Analysis ◽  
Sperm Characteristic ◽  
Computer Assisted Sperm Analysis ◽  
Fresh Semen

The aim of the study was to evaluate the effect of two different extenders on sperm characteristic before equilibration and post-thaw in the endangered Old Kladruber stallions. Also, the response of individual stallions to the extenders used was tested. Semen was collected from six stallions every other day within one week. After centrifugation of the collected sperm-rich fraction, the supernatant was removed and sperm pellets were divided to two aliquots; these were diluted either with Gent (Minitube, Germany) or privately manufactured lactose-EDTA-egg yolk extender (Lact). Three cryopreserved insemination doses (IDs) from each extender (Gent and Lact) were prepared for each stallion from one collection (108 samples from six stallions in total). As a parameter of quality, the motility (computer assisted sperm analysis), viability (fluorescence staining), and morphology (eosin/nigrosine staining) were evaluated after dilution with freezing extenders (fresh) and after thawing (frozen-thawed). The different effects of chosen extenders on the quality of fresh semen were only manifested in higher kinematic parameters of sperm when the Lact extender was used. However, in frozen-thawed samples, the Gent extender yielded significantly better results in all of the evaluated parameters. The representation of sperm subpopulation was significantly influenced by extender in fresh as well as frozen-thawed samples; moreover, we found a significant effect of freezing on the distribution of these subpopulations. The response of individual stallions to chosen extenders was evident in the different quality of fresh as well as frozen-thawed IDs; Gent extender yielded better frozen-thawed IDs. Based on our results, among others describing quality parameters of ejaculate in endangered Old Kladruber stallions, we can recommend using Gent extender for the production of frozen-thawed IDs.  

Simulation of No-Load Voltage of Single Phase Synchronous Generator Based on ANSYS

2011 ◽  
Vol 268-270 ◽  
pp. 231-234
Author(s):  
Jing Yang ◽  
Wei Jun Wang ◽  
Yong Gang Zuo ◽  
Ping Feng ◽  
Long Bo Mao
Keyword(s):  
Magnetic Field ◽  
Power Supply ◽  
Single Phase ◽  
Synchronous Generator ◽  
Simulation Method ◽  
Design Parameters ◽  
Test Results ◽  
Load Voltage ◽  
Simulation Results

The theory and method of analyzing the no-load magnetic field of single phase synchronous generator(SPSG) is presented in this article, and the no-load voltage of SPSG is simulated based on ANSYS program. The no-load voltage simulation results of a SPSG resemble its test results, which prove the simulation method in this article is correct and effective. The simulation results can provide theoretical bases and method for engineers in optimizing the design parameters to improve the power supply quality of SPSG.

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