scholarly journals Project of forming «culture and safety» of the airport

2018 ◽  
Vol 247 ◽  
pp. 00045 ◽  
Author(s):  
Andriy Ivanusa
Keyword(s):  
Mathematical Models ◽  
Mathematical Description ◽  
Critical Path ◽  
Probabilistic Method ◽  
Experimental Studies ◽  
Method Calculation ◽  
Synthesis Parameters ◽  
Methodological Principles ◽  
Evacuation Route ◽  
Method Analysis

Using the method analysis of the systems and synthesis parameters that influence on the process evacuation of people were certain. Methodological principles are used in relation to the management of people streams on the basis of the use critical path method, where the optimization synthesis of evacuation route people is considered as a topological chart of technological line, and an evacuation way is broken on separate parts. By means of probabilistic method and optimization synthesis of flexible technological lines topological case of users of airport streams frames are worked out and sometimes the evacuation. Conducted analysis of existent mathematical models, that describe motion streams of people on the objects of their mass stay showed that the stream users of the airport mutated and him mathematical description requires the synthesis of a few mathematical models. The method calculation time of evacuation users of the airport in that person informative base drawn on results other undertaken experimental studies is accordingly offered.

Calculation of the fire resistance of steel hollow structural section columns filled with plain concrete

1994 ◽  
Vol 21 (3) ◽  
pp. 382-385 ◽  
Author(s):  
T. T. Lie ◽  
D. C. Stringer
Keyword(s):  
Mathematical Models ◽  
Key Words ◽  
Fire Resistance ◽  
Experimental Studies ◽  
Plain Concrete ◽  
Building Codes ◽  
Aggregate Concrete ◽  
Parametric Studies ◽  
Hollow Structural Section ◽  
Hollow Structural Sections

Experimental studies were conducted to determine the fire resistance of circular and square hollow structural section columns filled with plain concrete. Mathematical models were developed and used to investigate the influence of important parameters that determine the fire resistance of these columns. The experimental and parametric studies provide information for the development of formulas for the calculation of the fire resistance of circular and square concentrically loaded columns filled with plain carbonate or siliceous aggregate concrete. Such formulas are suitable for incorporation into building codes. Key words: calculation, fire resistance, columns, concrete-filled, steel, hollow structural sections.

Mathematical models of optimal management of material support of educational and scientific activities of industrial universities

2020 ◽  
pp. 79-90
Author(s):  
N. V. Kalganova ◽  
Keyword(s):  
Higher Education ◽  
Mathematical Models ◽  
Numerical Solution ◽  
Mathematical Description ◽  
Financial Support ◽  
Software Package ◽  
Optimal Management ◽  
Material Support ◽  
Support Strategy ◽  
The University

The paper considers mathematical differential models for managing the achievement of planned values of material support for educational and scientific activities of the university based on the analysis of this area of activity of transport universities. Models contain a mathematical description of the material and financial processes under study, which analytically show their dynamics for a certain period. The models are quite simple and can be used for planning and forecasting the financial support strategy of higher education institutions. In her research, the author relied on the work of Russian scientists, in particular, on [1-5]. This paper presents a mathematical description of the set of possible options for the system, predicting the consequences of the implemented options, and justifying the rational choice of management to achieve optimal educational and material support of the university. In this paper, we used methods for solving and investigating differential equations, as well as the MathCAD 15 software package for their numerical solution [6-8].

scholarly journals The mathematical models for cutting force calculation during structural and corrosion-resistant steels` parts processing

2019 ◽  
Vol 298 ◽  
pp. 00099
Author(s):  
Alexey A. Zhdanov ◽  
Oleg A. Kursin ◽  
Pham Xuan Bach
Keyword(s):  
Mathematical Models ◽  
Cutting Force ◽  
Experimental Studies ◽  
Additional Parameter ◽  
Corrosion Resistant ◽  
Cutting Force Components ◽  
Force Components ◽  
Quantitative Indicators ◽  
Force Calculation ◽  
Thermo Physical Properties

The paper shows that conventional mathematical models for calculating the cutting force components during the turning process, represented in reference guides on engineering, give drastic errors reaching 100 percent or more for various tool-workpiece couples. These errors interfere with applying reference values of the cutting force for any further calculations, equipment selection, workpiece positioning scheme, workpiece deformation value due to the elastic of the technological system elements during processing and etc., because of the insufficient reliability of the results of such calculations. The paper proposes mathematical models obtained as a result of experimental studies, which allow for increasing the accuracy of the calculation of the components of the cutting force by introducing an additional parameter – i.e., the value of thermo EMF of the test running into the calculation formulas. This approach enables to reduce the error in the calculation of the components of the cutting force up to ± 15%. In addition, the need for the development of specific mathematical models for various groups of materials machined is shown, which is due to the peculiarities of contact processes in the machining of various groups of steels, as well as to qualitative and quantitative indicators of the thermo-physical properties of the materials of tool-workpiece contact couples.

A Mathematical Description of Pressures in Alveolar Pores of Kohn

1991 ◽  
Vol 113 (1) ◽  
pp. 104-107 ◽  
Author(s):  
De-fu Lu ◽  
Charles Stanley ◽  
German Nunez ◽  
David Frazer
Keyword(s):  
Surface Tension ◽  
Mathematical Models ◽  
Pore Size ◽  
Lung Tissue ◽  
Mathematical Description ◽  
Disease Process ◽  
Liquid Interface ◽  
Tissue Destruction ◽  
Air Liquid Interface ◽  
Pore Enlargement

Small interalveolar holes within the lung are called pores of Kohn. Some researchers have correlated enlarged pore size with diseases, e.g. emphysema, that are characterized by tissue destruction. Mathematical models of the pressures generated in closed, fluid-filled and open, fluid-lined pores demonstrate that pressures capable of rupturing lung tissue can be developed in a pore due to the surface tension and shape of the air-liquid interface. Pore enlargement accompanied by tissue destruction is presented as a possible mechanism for the disease process observed during aging and the development of emphysema in the lung.

Dynamics of the brain: Mathematical models and non-invasive experimental studies

2013 ◽  
Vol 222 (10) ◽  
pp. 2607-2622 ◽  
Author(s):  
V. Toronov ◽  
T. Myllylä ◽  
V. Kiviniemi ◽  
V.V. Tuchin
Keyword(s):  
Mathematical Models ◽  
Experimental Studies ◽  
Non Invasive ◽  
The Brain

Laboratory Stand for Air Flow Stabilization

2006 ◽  
Vol 113 ◽  
pp. 119-124
Author(s):  
Arūnas Lipnickas ◽  
Ramunė Jankauskaitė ◽  
Vilmantas Žukauskas ◽  
Vaclovas Kubilius
Keyword(s):  
System Identification ◽  
Fault Detection ◽  
Mathematical Models ◽  
Mathematical Description ◽  
Detection System ◽  
Air Flow ◽  
Real System ◽  
Identification System ◽  
Stabilization System ◽  
Flow Stabilization

In this paper the methodology of composing mathematical models and fault detection & identification system for a laboratory stand named air flow stabilization system is given. The main objective of the system identification is to obtain the best mathematical description of a real system of interest; in our case we have modeled the dynamics of air flow in the tube. In the second part of the paper the authors present the fault detection system that is designed to detect any abnormality of air flow in the air tube and to identify four types of occurred faults.

scholarly journals RESULTS OF EXPERIMENTAL STUDIES OF ACCELERATIONS OF THE DM-617 VIBRATORY ROLLER USING DIGITAL SIGNAL PROCESSING TECHNOLOGY

2020 ◽  
Vol 17 (2) ◽  
pp. 182-195
Author(s):  
I. S. Tiuremnov ◽  
S. N. Ivanov ◽  
A. S. Kraiushkin
Keyword(s):  
Mathematical Models ◽  
Dynamic Modulus ◽  
Vibration Mode ◽  
Operation Mode ◽  
Experimental Studies ◽  
Vertical Vibration ◽  
Vertical Acceleration ◽  
Soil Deformation ◽  
Compacted Soil ◽  
Vertical Accelerations

Introduction. To improve the vibrating rollers in order to increase sealing capacity, reliability and vibration safety, the interaction of vibrating roller parts between each other and with compacted soil is simulated mathematically. The developed models are validated, i.e. compared with the results of experimental studies. However, the known results of experimental studies were obtained based on a relatively small list of vibrating roller models and soil types, as well as in a steady vibration mode. The paper presents the results of experimental studies, which used a vibratory drum of a roller to study its vertical vibration accelerations both in the steady vibration, as well as transient mode at turning the vibration generator on (speedup) and off (halt). This expands the range of opportunities to validate the existing and newly developed mathematical models.Materials and methods. Experimental studies of vertical vibration accelerations of a drum were conducted using the DM-617 vibrating roller when compacting natural sand-gravel aggregate. The accelerometer readings show high-frequency harmonics, which makes it significantly more difficult to determine amplitude values of vibration accelerations, therefore a low-frequency filter with a boundary frequency of 200 Hz was used for digital processing.Results. It was determined that when the DM-617 vibrating roller is compacting soil with maximum driving force within the range of variation of dynamic modulus of soil deformation Evd=14…25 MPа, amplitude values of vertical vibration accelerations of the vibratory drum are from 65... 77 to -61... -69 m/s2 . At the start-up (speedup) of vibration generator, acceleration amplitudes are 1.1 times higher than vertical accelerations of steady operation mode of the vibrating drum and practically do not depend on the dynamic modulus of soil deformation Evd. At turning off (stop) of the vibration generator, amplitude of vertical accelerations do not exceed the vertical accelerations of the steady operation mode of the vibratory drum.Discussion and conclusion. The vertical acceleration amplitudes of vibratory drums of DM-617 do not depend on the dynamic soil deformation modulus Evd, and this is consistent with the results of experimental studies of the vibratory drum mounted on DM-614. The obtained vertical vibration accelerations of the drum mounted on DM-617 in the steady vibration mode, as well as at switching the vibration generator on (speedup) and off (halt) make it possible to verify the existing and developed mathematical models of interaction of vibrating rollers with compacted soil.Financial transparency: the authors have no financial interest in the presented materials or methods. There is no conflict of interest.

scholarly journals THE STUDY OF THE METHOD OF FIGHT AGAINST FORMATION OF POLARIZING LAYER AT THE PROCESS OF ULTRAFILTRATION CONCENTRATION OF THE SKIM MILK

2016 ◽  
Vol 5 ◽  
pp. 53-60
Author(s):  
Grygoriy Deynychenko ◽  
Vasyl Guzenko ◽  
Oleg Udovenko ◽  
Aleksandr Omelchenko ◽  
Olga Melnik
Keyword(s):  
Mathematical Models ◽  
Membrane Surface ◽  
Experimental Studies ◽  
Skim Milk ◽  
Factorial Experiment ◽  
Raw Material ◽  
Technological Parameters ◽  
Membrane Processing ◽  
Working Parameters ◽  
Selection Of

The description of experimental set and the method of processing of the results of the study of the method of fight against formation of polarizing layer in the process of ultrafiltration concentration of skim milk raw material were presented. The results of experimental studies relative to the sparging method application for the prevention of polarizing layer in the process of membrane processing of the skim milk and its influence on the capacity of ultrafiltration membranes were offered. The mathematical models were constructed on the base of regressive equations of factorial experiment using the method of the raw material sparging above the membrane surface for selection of technological parameters of the process of ultrafiltration concentration of the skim milk. The rational working parameters of the process of ultrafiltration concentration of the skim milk using the sparging of the skim milk by the gas bubbles in the direct closeness to the membrane surface were determined. Such working parameters are: pressure– 0,4...0,5 MPa, temperature of skim milk– 40...50 ºС, frequency of sparging of skim milk– 0,10...0,15 min-1, pressure of sparging must be 0,56...0,58 MPa.

scholarly journals Keep your droplets to yourself: Universal use of face masks along with social distancing

2021 ◽  
Vol 19 (2) ◽  
pp. 114-123
Author(s):  
Helena Carvalho ◽  
Daniel Contaifer Jr ◽  
Renata N. Aranha ◽  
Juliana A. De Matos
Keyword(s):  
Hand Hygiene ◽  
Mathematical Models ◽  
Control Mechanism ◽  
Respiratory Infections ◽  
Experimental Studies ◽  
World Health ◽  
Source Control ◽  
The World ◽  
Viral Respiratory Infections ◽  
Viral Respiratory

Introduction: As the COVID-19 pandemic progresses aroundthe world, the universal use of face masks imposes itself as ameasure to mitigate the transmission of SARS-CoV-2 and iscurrently recommended by the World Health Organization.However, its effectiveness as a method of preventing COVID-19 is still controversial. Objective: To review the literatureon the universal use of facial masks, including fabric ones, andtheir recommendations for use. Methods: Narrative reviewof published studies on the topic. Results: Face masks act predominantlyas a source control mechanism, as they capturethe droplets expelled by the user when speaking, coughingor sneezing, protecting other people and the environmentfrom contamination by potentially infecting droplets. Evidenceof the effectiveness of its universal use as a method ofmitigating epidemics of viral respiratory infections is derivedfrom experimental studies and mathematical models. Properuse of facial masks is essential to ensure their effectivenessand prevent damage, and includes covering the nose, mouthand chin, washing the fabric masks with soap and water afteruse and hand hygiene several times a day, especially whenhandling the mask. Conclusions: The universal use of facialmasks in the context of the COVID-19 pandemic is justified,especially considering the occurrence of virus transmissionin the pre-symptomatic period, and should be adopted inconjunction with other measures such as adequate socialdistance and hygiene from the hands, following the motto“I protect you and you protect me”.

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