scholarly journals Simulation of Intermittent Turning Processes

1991 ◽  
Vol 113 (3) ◽  
pp. 458-466 ◽  
Author(s):  
G. M. Zhang ◽  
S. Yerramareddy ◽  
S. M. Lee ◽  
S. C.-Y. Lu
Keyword(s):  
Simulation Model ◽  
Initial Value ◽  
Principle Of Superposition ◽  
Practical Applications ◽  
Vibratory Motion ◽  
Intermittent Turning ◽  
Experimental Findings ◽  
The Impact ◽  
Chip Load

A simulation model is developed to study the dynamic characteristics of intermittent turning operations. Factors such as chip load, free-vibration of the toolpost structure, and nonhomogeneous hardness distribution in the material being cut are incorporated in the model. The principle of superposition is used in the formulation of the simulation algorithm. The impact between the cutting tool and the workpiece at the start of every cutting period during machining is treated as an initial value problem. The simulation model provides a quantitative evaluation of the tool vibratory motion during the intermittent turning process. Study of the cutting dynamics based on the simulation results not only confirms the experimental findings, but also indicates that increasing the static stiffness of the toolpost structure is an effective approach to control the tool vibratory motion. The determination of probability of tool breakage under various spindle speed settings is presented as an example to demonstrate the practical applications of the simulation model developed in this work.

Experimental and Theoretical Investigation of a Turbine Foundation

1940 ◽  
Vol 7 (2) ◽  
pp. A63-A70
Author(s):  
Sergius Vesselowsky
Keyword(s):  
Elastic Constants ◽  
Critical Frequency ◽  
Deformable Body ◽  
Theoretical Treatment ◽  
Natural Vibrations ◽  
Experimental Part ◽  
Vibratory Motion ◽  
Experimental Findings ◽  
Theoretical Results

Abstract This paper contains the results of a study made on a turbine foundation for the purpose of elucidating conditions which favor the building up of excessive vibrations when the unit is in operation. The structure studied was a steel framework supporting a concrete table with a turbogenerator erected on it. The experimental part consists of (a) dynamical loading of the structure and (b) determination of its elastic constants. The theoretical treatment of the problem consists of the determination of the frequencies and the modes of the natural vibrations by analytical methods. A comparison of the theoretical results obtained with the experimental findings is made. The results of the study indicate that vibrations of a turbogenerator on its foundation, for units of conventional design, can be treated as vibratory motion of a deformable body supported by a system of massless springs. Some rules to be followed in designing and means of changing a critical frequency in a desired sense also are included. The present investigation was undertaken in an effort to eliminate the uncertainty which exists in the design of the foundations for turbogenerators, particularly where a steel substructure is used.

Piston dynamics analysis considering skirt-liner dynamic clearance

2019 ◽  
Vol 233 (13) ◽  
pp. 3538-3553 ◽  
Author(s):  
Jingyi Tian ◽  
Huihua Feng ◽  
Yuanjie Feng ◽  
Zhengwei Yang ◽  
Chengjun Zhu ◽  
...  
Keyword(s):  
Simulation Model ◽  
High Frequency ◽  
Thermal Deformation ◽  
Structural Parameters ◽  
Accurate Determination ◽  
Low Noise ◽  
Dynamics Analysis ◽  
Piston Skirt ◽  
The Impact

Piston slap force is one of the main sources of mechanical engine noise. To obtain a more accurate determination of the piston slap force and minimize piston slap noise, a new simulation model that considers dynamic clearance of the piston skirt and liner has been established in this study. The skirt-liner dynamic clearance is caused mainly by the elastic deformation and thermal deformation of the piston. Comparing three different models, it was found that the impact of dynamic clearance on the piston slap force is reflected mainly in the medium-high frequency, which is the sensitive frequency of the slap noise. Therefore, it is necessary to consider dynamic clearance in the simulation model. In addition, the mechanisms behind the dynamic clearance effect on fluid lubrication, piston dynamics, and piston slap noise were observed. In particular, three typical structural parameters in piston dynamics (the piston pin offset, piston-liner clearance, and piston skirt profile) were studied. The analyses provide guidance for the design of low-noise engines.

Development of a simulation model for the Port of Thunder Bay

1986 ◽  
Vol 13 (1) ◽  
pp. 59-65 ◽  
Author(s):  
Said M. Easa
Keyword(s):  
Simulation Model ◽  
Queue Length ◽  
Simulation Models ◽  
Structure Design ◽  
Computer Simulation Model ◽  
Practical Applications ◽  
Thunder Bay ◽  
Port Throughput ◽  
The Impact ◽  
Measures Of Performance

This paper presents a computer simulation model, PORTSIM, that was developed for the grain terminals of the Port of Thunder Bay. In addition to simulating ship arrival and grain loading characteristics, the model incorporates two distinct features of the port. These features are the movements of ships between berths to load different grades of grain and the impact of the rail-side operation on port performance.The paper first reviews existing simulation models and presents an overview of the operations of the port. Model details are then presented and include its logic and structure, design of experiments, measures of performance, and model input/output. In particular, the model provides several measures of performance, including average waiting time of ships, average queue length, berth utilization, port throughput, and maximum queue length. These measures are useful in assessing future improvements in the port. Some practical applications of the model and areas of future expansion of its capabilities are discussed. Key words: port, grain terminals, simulation model, ship arrival, grain loading, performance measures, practical applications.

Assessment of sensitivity of the efficiency of regional tax spending towards investment attractiveness of the types of economic activity carried out by the residents of advanced development territory

2020 ◽  
pp. 98-110
Author(s):  
Evgeniya Mikhailovna Popova ◽  
Guzel Mukhtarovna Guseinova ◽  
Sergei Borisovich Milov
Keyword(s):  
Economic Activity ◽  
Socioeconomic Development ◽  
Federal District ◽  
Tax Incentives ◽  
Capital Investments ◽  
The Subject ◽  
Investment Process ◽  
The Impact ◽  
Advanced Development

The deficit of subnational budgets and deceleration capital investments in multiple Russian regions increase the relevance of research aimed at improvement of tax incentivizing practice of the regional investment process. The studies focused on determination of the impact of socioeconomic and institutional factors upon the efficiency of investment tax expenses obtained wide circulation within the foreign scientific literature. The subject of this article is the assessment of sensitivity of the efficiency of regional tax expanses towards investment attractiveness of the types of economic activity carried out by the residents of territories of advanced socioeconomic development, created in the subjects of Far Easter Federal District. The scientific novelty and practical values of this research consists in substantiation of the reasonableness of assessment of investment attractiveness of the types of economic activity that are stimulated by tax incentives. Methodology for assessing investment attractiveness is proposed and tested. The conclusion is made that in case of low investment attractiveness of the type of economic activity, which was planned to support by tax incentives, it is required to conduct and additional analysis to avoid unjustified tax expanses.

Method development for the determination of textural properties of sugar beet roots

2019 ◽  
pp. 392-400 ◽  
Author(s):  
Gunnar Kleuker ◽  
Christa M. Hoffmann
Keyword(s):  
Sugar Beet ◽  
Compression Test ◽  
Storage Period ◽  
Textural Properties ◽  
Small Sample ◽  
Root Tip ◽  
Flexural Test ◽  
Sample Distribution ◽  
The Impact

The harvest of sugar beet leads to root tip breakage and surface damage through mechanical impacts, which increase storage losses. For the determination of textural properties of sugar beet roots with a texture analyzer a reliable method description is missing. This study aimed to evaluate the impact of washing, soil tare, storage period from washing until measurement, sample distribution and number of roots on puncture and compression measurements. For this purpose, in 2017 comprehensive tests were conducted with sugar beet roots grown in a greenhouse. In a second step these tests were carried out with different Beta varieties from a field trial, and in addition, a flexural test was included. Results show that the storage period after washing and the sample distribution had an influence on the puncture and compression strength. It is suggested to wash the roots by hand before the measurement and to determine the strength no later than 48 h after washing. For reliable and comparable results a radial distribution of measurement points around the widest circumference of the root is recommended for the puncture test. The sample position of the compression test had an influence on the compressive strength and therefore, needs to be clearly defined. For the puncture and the compression test it was possible to achieve stable results with a small sample size, but with increasing heterogeneity of the plant stand a higher number of roots is required. The flexural test showed a high variability and is, therefore, not recommended for the analysis of sugar beet textural properties.

Development and Validation of an LC-MS/MS Method for Simultaneous Determination of Canagliflozin and Metformin HCl in Rat Plasma and its Application

2020 ◽  
Vol 16 (6) ◽  
pp. 752-762
Author(s):  
Vivek Nalawade ◽  
Vaibhav A. Dixit ◽  
Amisha Vora ◽  
Himashu Zade
Keyword(s):  
Internal Standard ◽  
Rat Plasma ◽  
Precipitation Method ◽  
Herbal Extracts ◽  
One Step ◽  
Precision And Accuracy ◽  
Development And Validation ◽  
The Impact ◽  
Metformin Hcl

Background: Food and herbal extracts rich in Quercetin (QRT) are often self-medicated by diabetics and can potentially alter the pharmacokinetics (PK) of Metformin HCl (MET) and Canagliflozin (CNG) leading to food or herb-drug interactions and reduced therapeutic efficacy. However, the impact of these flavonoids on the pharmacokinetic behaviour of MET and CNG is mostly unknown. Methods: A simple one-step protein precipitation method was developed for the determination of MET and CNG from rat plasma. The mobile phase chosen was MeOH 65% and 35% water containing 0.1% formic acid at a flow rate of 1mL/min. Results: The retention time of MET, internal standard (Valsartan) and CNG was 1.83, 6.2 and 8.2 min, respectively. The method was found to be linear in the range of 200 - 8000 ng/mL for CNG and 100 = 4000 ng/ml for MET. Precision and accuracy of the method were below 20% at LLOQ and below 15% for LQC, MQC, and HQC. Conclusion: The method was successfully applied for the determination of PK of MET and CNG by using 100 μL of rat plasma. QRT co-administration affects the PK parameters of MET and CNG. This alteration in PK parameters might be of significant use for clinicians and patients.

COVID-19: Time-Dependent Effective Reproduction Number and Sub-notification Effect Estimation Modeling (Preprint)

2020 ◽  
Author(s):  
Eduardo Atem De Carvalho ◽  
Rogerio Atem De Carvalho
Keyword(s):  
New York ◽  
Reproduction Number ◽  
Moving Average ◽  
Real Data ◽  
Time Dependent ◽  
Initial Value ◽  
Health Authorities ◽  
Reproduction Numbers ◽  
Effect Estimation ◽  
The Impact

BACKGROUND Since the beginning of the COVID-19 pandemic, researchers and health authorities have sought to identify the different parameters that govern their infection and death cycles, in order to be able to make better decisions. In particular, a series of reproduction number estimation models have been presented, with different practical results. OBJECTIVE This article aims to present an effective and efficient model for estimating the Reproduction Number and to discuss the impacts of sub-notification on these calculations. METHODS The concept of Moving Average Method with Initial value (MAMI) is used, as well as a model for Rt, the Reproduction Number, is derived from experimental data. The models are applied to real data and their performance is presented. RESULTS Analyses on Rt and sub-notification effects for Germany, Italy, Sweden, United Kingdom, South Korea, and the State of New York are presented to show the performance of the methods here introduced. CONCLUSIONS We show that, with relatively simple mathematical tools, it is possible to obtain reliable values for time-dependent, incubation period-independent Reproduction Numbers (Rt). We also demonstrate that the impact of sub-notification is relatively low, after the initial phase of the epidemic cycle has passed.

The Microeconomics of Product Innovation

2018 ◽  
Author(s):  
Paul Stoneman ◽  
Eleonora Bartoloni ◽  
Maurizio Baussola
Keyword(s):  
Product Innovation ◽  
New Products ◽  
Goods And Services ◽  
Product Innovations ◽  
Microeconomic Analysis ◽  
Prime Objective ◽  
Price Measurement ◽  
The Impact

The prime objective of this book is the use microeconomic analysis to guide and provide insight into the generation and adoption of new products. Taking an approach that uses minimal formal mathematics, the volume initially addresses questions of definitions, sources, and extent of product innovation, differentiating between goods and services; hard and soft innovations; horizontal and vertical innovations; original, new to market, and new to firm innovations. The sources of product innovations (e.g. R&D, design, and creativity) are explored empirically, and the extent of such innovations is then pursued using survey and other data. Three chapters are devoted to the theoretical analysis of the demand for and supply of new products and to the determination of firms’ decisions to undertake product innovation. Later chapters encompass empirical evidence on the determination of the extent of product innovation, the diffusion of such innovation, the impact of product innovation on firm performance, price measurement, and welfare, while the final chapter addresses policy issues.

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