scholarly journals Simulation of the Flat-parallel Movement of a Bridge Agricultural Unit with an Articulated Frame

2020 ◽  
Vol 44 (339) ◽  
pp. 8-14
Author(s):  
Volodymyr Bulgakov ◽  
Semjons Ivanovs ◽  
Volodymyr Volskyi ◽  
Volodymyr Kuvachоv ◽  
Yevhen Ihnatiev
Keyword(s):  
Mathematical Models ◽  
Angular Displacement ◽  
Dynamic Control ◽  
Frequency Characteristics ◽  
Operating Modes ◽  
Parallel Movement ◽  
Kinematic Method ◽  
Dynamic Control System ◽  
Calculated Amplitude ◽  
The Impact

AbstractThe work presents foundations of the dynamics of the flat-parallel movement of a bridge agricultural unit in a horizontal with the kinematic method of its control (turning the wheels) by changing the position of one of its parts relative to the other. The analysis of assessment of the degree of impact of the scheme and parameters of the investigated agricultural tool upon its controllability and stability of movement is based on the amplitude and phase frequency characteristics. The mathematical models of the movement of the bridge agricultural unit are presented in a differential and an operator form of recording. Based on mathematical models, the calculated amplitude and phase frequency characteristics of the dynamic control system of the control impact, presented as the angular displacement of its half-frames ψ, are constructed for various parameters and operating modes. The constructed mathematical models, amplitude and phase frequency characteristics make it possible to assess the impact of the control parameter of the bridge agricultural unit, as well as its design and other parameters upon the controllability of the movement.

scholarly journals Bioreactor and Bioprocess Design Issues in Enzymatic Hydrolysis of Lignocellulosic Biomass

Catalysts ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 680
Author(s):  
Giuseppe Olivieri ◽  
René H. Wijffels ◽  
Antonio Marzocchella ◽  
Maria Elena Russo
Keyword(s):  
Lignocellulosic Biomass ◽  
Enzymatic Saccharification ◽  
Product Inhibition ◽  
Cellulolytic Enzymes ◽  
Main Process ◽  
Bioprocess Design ◽  
Operating Modes ◽  
Biomass Saccharification ◽  
Starting Point ◽  
The Impact

Saccharification of lignocellulosic biomass is a fundamental step in the biorefinery of second generation feedstock. The physicochemical and enzymatic processes for the depolymerization of biomass into simple sugars has been achieved through numerous studies in several disciplines. The present review discusses the development of technologies for enzymatic saccharification in industrial processes. The kinetics of cellulolytic enzymes involved in polysaccharide hydrolysis has been discussed as the starting point for the design of the most promising bioreactor configurations. The main process configurations—proposed so far—for biomass saccharification have been analyzed. Attention was paid to bioreactor configurations, operating modes and possible integrations of this operation within the biorefinery. The focus is on minimizing the effects of product inhibition on enzymes, maximizing yields and concentration of sugars in the hydrolysate, and reducing the impact of enzyme cost on the whole process. The last part of the review is focused on an emerging process based on the catalytic action of laccase applied to lignin depolymerization as an alternative to the consolidated physicochemical pretreatments. The laccases-based oxidative process has been discussed in terms of characteristics that can affect the development of a bioreactor unit where laccases or a laccase-mediator system can be used for biomass delignification.

Flow Assurance and Thermodynamic Challenges of operating CO2 Pipelines for variations in terrains and environments

2021 ◽  
Author(s):  
Terence George Wood ◽  
Scott Campbell ◽  
Nathan Smith
Keyword(s):  
Process Equipment ◽  
Fluid Composition ◽  
Ambient Conditions ◽  
Operating Modes ◽  
Hydrocarbon Reservoir ◽  
Compositional Approach ◽  
Operational Life ◽  
Geographical Distances ◽  
Fluid Behaviour ◽  
The Impact

Abstract The requirement for capturing and storing Carbon Dioxide will continue to grow in the next decade and a fundamental part of this is being able to transport the fluid over large geographical distances in numerous terrains and environments. The evolving nature of the fluid supply and the storage characteristics ensure the operation of the pipeline remains a challenge throughout its operational life. This paper will examine the impact of changes in the fluid composition, storage locations, ambient conditions and the various operating modes the pipeline will see throughout the lifecycle, highlight the technical design and operational challenges and finally give guidance on future developments. The thermodynamic behaviour of CO2 with and without impurities will be demonstrated utilising the fluid characterisation software, MultiflashTM. The fluid behaviour and hydraulic performance will be calculated over the expected operational envelope of the pipeline throughout field life, highlighting the benefits and constraints of using the single component module in OLGATM whilst comparing against a compositional approach when dealing with impurities. The paper will demonstrate through two case studies of varying nature including geographical environment, storage location (aquifer vs. abandoned hydrocarbon reservoir) and ambient conditions, the following issues: The impact of the storage type on the pipeline operations and how this will evolve with time; The environmental conditions and the impact these have on selection of process equipment and operational procedures (i.e. shutdown); and The impact the CO2 composition has on the design of the CO2 pipeline, and The paper will conclude with a set of guidelines for undertaking design analysis of CO2 pipelines for variations in fluid composition, storage locations and ambient conditions as well as some key operational strategies. This paper utilises the current state of the art tools and how these evolving tools are making this technically challenging area more mainstream.

scholarly journals Modelling the HIV-Associated TB Epidemic and the Impact of Interventions Aimed at Epidemic Control

2019 ◽  
pp. 25-55
Author(s):  
P. J. Dodd ◽  
C. Pretorius ◽  
B. G. Williams
Keyword(s):  
Natural History ◽  
Mathematical Models ◽  
Population Level ◽  
Explicit Representation ◽  
Epidemic Control ◽  
Future Directions ◽  
Individual Level ◽  
Tuberculosis Epidemiology ◽  
History Of ◽  
The Impact

Abstract In this chapter, we focus on mathematical models of tuberculosis epidemiology (TB) that include interactions with HIV and an explicit representation of transmission. We review the natural history of TB and illustrate how its features are simplified and incorporated in mathematical models. We then review the ways HIV influences the natural history of TB, the interventions that have been considered in models, and the way these individual-level effects are represented in models. We then go on to consider population-level effects, reviewing the TB/HIV modelling literature. We first review studies whose focus was on purely epidemiological modelling, and then studies whose focus was on modelling the impact of interventions. We conclude with a summary of the uses and achievements of TB/HIV modelling and some suggested future directions.

scholarly journals NECESSITY TO IMPROVE THE MATHEMATICAL MODEL OF FREIGHT CARS TO STUDY CASES OF ITS DERAILMENTS

2020 ◽  
pp. 442-451
Author(s):  
А.V. Batig ◽  
A. Ya. Kuzyshyn
Keyword(s):  
Mathematical Model ◽  
Mathematical Models ◽  
Computer Experiment ◽  
Rolling Stock ◽  
Software Systems ◽  
Freight Car ◽  
The Stability ◽  
The Many ◽  
The Impact ◽  
The Mathematical Model

One of the most important problems that pose a serious threat to the functioning of railways is the problem of freight cars derailment. However, according to statistics, the number of cases of the derailments of freight cars in trains annually grows. Тo prevent such cases, the necessary preventive measures are developed, and to study the causes of their occurrence, a significant number of mathematical models, programs and software systems created by leading domestic and foreign scientists. Studies of such mathematical models by the authors of this work have led to the conclusion that they are not sufficiently detailed to the extent that it is necessary for analyze the reasons of its derailment. At the same time, an analysis of the causes of the rolling stock derailments on the railways of Ukraine over the past five years showed that in about 20 % of cases they are obvious, and in 7 % of cases they are not obvious and implicitly expressed. The study of such cases of rolling stock derailment during an official investigation by the railway and during forensic railway transport expertises requires the use of an improved mathematical model of a freight car, which would allow a quantitative assessment of the impact of its parameters and rail track on the conditions of railway accidents. Therefore, taking into account the main reasons that caused the occurrence of such railroad accidents over the last five years on the railways of Ukraine, the article selected the main directions for improving the mathematical model of a freight car, allowing to cover all the many factors (explicit and hidden) and identify the most significant ones regarding the circumstances of the derailment rolling stock off the track, established on the basis of a computer experiment. It is proposed in the mathematical model of a freight car to take into account the guiding force, the value of which is one of the main indicators of the stability of the rolling stock. The authors of the article noted that not taking into account the influence of the guiding forces on the dynamics of the freight car can lead to an erroneous determination of the reasons for the rolling stock derailment or even to the impossibility of establishing them.

scholarly journals Models and Algorithms of Adaptive Animal Flow Control in Rotary Milking Parlors

2019 ◽  
Vol 67 (6) ◽  
pp. 1465-1484
Author(s):  
Vladimir V. Kirsanov ◽  
Andrey Y. Izmaylov ◽  
Yakov P. Lobachevsky ◽  
Oksana A. Tareeva ◽  
Sergey N. Strebulyaev ◽  
...  
Keyword(s):  
Mathematical Models ◽  
High Performance ◽  
Dairy Farm ◽  
Computing System ◽  
Scientific Basis ◽  
Idle Time ◽  
Functional Connection ◽  
Operating Modes ◽  
Nizhny Novgorod Region ◽  
Physiological Characters

The study addresses the influence of milking duration of individual cows on the performance of conveyor-like rotary milking parlors and seeks to optimize their operation parameters and operating modes. The observational experiment was conducted in the Zhdanovsky Farm in Nizhny Novgorod Region, Russia. The dairy farm had a herd of 600 cows, divided into 10 groups by physiological characters and milk yield, and operated a 36 point milking parlor. Distribution of milking time of individual cows was studied using statistical analysis methods. The cyclogram of parlor operation and the functional connection of main parameters were analyzed using Maple analytical computing system, including its standard libraries and functions. The trends in idle time, which occurs due to undermilking of animals in one turn of the parlor, were studied. The idle time can result in overestimation of the number of stalls or decrease in the nameplate performance of the milking parlor by 30–40% from 120 to 93 cows per hour. Mathematical models, taking into account the influence of the milking time of individual animals (2 to 17 minutes) on the parameters of parlor operation, were developed. The algorithms of adaptive control over the rotational speed were proposed to minimize idle time in parlor operation and maintain the nameplate performance. The mathematical models, control algorithms and developed software can serves as a scientific basis for new designs of high-performance rotary milking parlors.

EXPERIMENTAL RESEARCH ON COMPRESSION FOAM COOLING DURING ITS DELIVERY AT DIFFERENT AMBIENT TEMPERATURE MODES

2021 ◽  
Vol 4 ◽  
pp. 40-44
Author(s):  
Gumirov A. ◽  
Keyword(s):  
Experimental Data ◽  
Mathematical Model ◽  
Low Temperatures ◽  
Empirical Method ◽  
Research Application ◽  
Mass Consumption ◽  
Operating Modes ◽  
Research Findings ◽  
Conducting Research ◽  
The Impact

Purpose. The article describes methodology for conducting research on parameters of compression foam cooling during its delivery through hose-pump systems depending on the operating modes of the foam generating installation. The impact of mass consumption of compression foam on its cooling at low temperatures has been examined. The application of a mathematical model of air-foam mixture movement in hose-pump systems at different temperature modes has been substantiated. Methods. Empirical method-experiment has been used for research. Findings. A number of experiments have been carried out to confirm the developed model of compression foam moving in hose-pump systems at different temperature modes. A mobile installation for generating and delivering compression foam has been used as the object of the research. Inaccuracy in calculations obtained with the help of a mathematical model in comparison with the experimental data is 10% which makes a possible to claim that the model of compression foam moving in hose-pump systems at different temperature modes has been chosen properly. Research application field. According to the obtained data, it is possible to plan means and forces of fire units for extinguishing fires using compression foam at low temperatures. Conclusions. The developed mathematical model of compression foam movement during its delivery through hose-pump systems is confirmed by experimental data. The dependence of mass consumption impact on compression foam cooling when it is delivered through fire hoses at low temperatures has been obtained experimentally.

A novel model-based robust control design for collaborative robot joint module

2022 ◽  
pp. 095440622110547
Author(s):  
ShengChao Zhen ◽  
WangXu Cui ◽  
XiaoLi Liu ◽  
GuanJun Meng ◽  
Ye-Hwa Chen
Keyword(s):  
Numerical Simulation ◽  
Robust Control ◽  
Trajectory Tracking ◽  
Dynamic Performance ◽  
Dynamic Control ◽  
Robot System ◽  
Excellent Control ◽  
Robust Control Design ◽  
The Impact ◽  
Collaborative Robot

In order to reduce the impact of load and system parameter changes on the dynamic performance of collaborative robot joint module, a novel robust control algorithm is proposed in this paper to solve the problem of dynamic control of collaborative robot joint module trajectory tracking. The controller is composed of two parts: one is a nominal control term designed based on the dynamical model, aiming to stabilize the nominal robot system; the other is a robust control term based on the Lyapunov method, aiming to eliminate the influence of uncertainty on tracking performance, where the uncertainties include nonlinear friction, parameter uncertainty, and external disturbances. The Lyapunov minimax method is adopted to prove that the system is uniformly bounded and uniformly ultimately bounded. We performed numerical simulation and experimental validation based on an actual collaborative robot joint module experimental platform and the rapid controller prototype cSPACE. The numerical simulation and experimental results show that the controller has excellent control performance for the collaborative robot joint module and provides more accurate trajectory tracking under the influence of uncertainties.

How to model the impact of climate change on vector-borne diseases?

2021 ◽  
pp. 26-31
Author(s):  
Cyril Caminade
Keyword(s):  
Climate Change ◽  
Risk Assessment ◽  
Mathematical Models ◽  
Future Climate ◽  
Future Climate Change ◽  
Climate Change Risk ◽  
Vector Borne Diseases ◽  
Impact Of Climate Change ◽  
Vector Borne ◽  
The Impact

Abstract This expert opinion provides an overview of mathematical models that have been used to assess the impact of climate change on ticks and tick-borne diseases, ways forward in terms of improving models for the recent context and broad guidelines for conducting future climate change risk assessment.

Philosophy of Economics

2018 ◽  
Author(s):  
Mikaël Cozic
Keyword(s):  
Behavioral Economics ◽  
Mathematical Models ◽  
A Priori ◽  
The Core ◽  
Philosophy Of Economics ◽  
Empirical Significance ◽  
Bona Fide ◽  
The Impact ◽  
Empirical Methodology ◽  
Recent Extension

Although there are no doubts regarding the impact of economics in society and politics, doubts regarding its epistemological status endure. Does economics provide us with bona fide empirical theories? Are its mathematical models on a par with those of the hard sciences, or is its scientific character exaggerated? This chapter focuses on the key problem of the philosophy of economics: the reconciliation of its claim to empirical significance with what often appears as a non-empirical methodology, favoring deduction from a priori principles and showing little sensitivity to refutation by observation and experiment. Several attempts at answering this problem are considered, both in the Millian tradition and following neo-positivist approaches. Finally, the empirical status of the discipline is put in perspective with its recent extension to new fields of inquiry, such as behavioral economics and neuroeconomics, where experiments seem to be part of the core methodology.

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