Help Of Simulations Research Articles

Cardiac Simulations: Computer Games to Mend Broken Hearts

The heart is the organ in charge of pumping blood to the rest of the body. But the heart can get sick, and we want to know how to best mend it. Sometimes, doctors can give medicines or do heart surgery to treat heart problems. But some medicines may not work for everyone, and surgeries can be very difficult. Now we have special computer games to better guide these decisions: cardiac simulations. Cardiac simulations are like having a twin of the heart in the computer. Doctors can try different medicines in the simulation without putting the patient at risk. They can also use the heart simulation to practice for surgery. They can train using the simulation until they are ready, and then do the surgery in the real world. With the help of computer simulations, we can find the best way to help sick hearts.

Компьютерное моделирование процессов формирования усреднительного склада горнодобывающего предприятия

The work is devoted to the issues of applied use of the concept of digital twins for the problems of averaging the quality of ore in mining enterprises. The authors consider the problem of automation of the processes of formation of the blending ore stockpile with the help of computer simulation. It is proposed to use matrix structures as a formal basis for representing a warehouse stack. The article describes an algorithm for determining the sequence and position of unloading a vehicle in a stack when forming a blending warehouse, taking into account the schedule of movement of transport units, as well as the procedure for checking the possibility of unloading a vehicle into a given cell of a stack, which is implemented using a modification of the branch and bound algorithm. A brief description of the processes for visualizing the results of the work of the developed algorithms using 3D animation in the Unity environment is also given.

Modeling the control processes of the size population of microorganisms using modulated microwave

The paper describes a mathematical model of a control system for the size population of microorganisms using modulated microwave radiation of non-thermal power.The model is implemented in the dynamic environment MATLAB+Simulink, the areas of optimal values of the impact parameters are found. An algorithm for automatic tuning of the modulation frequency during the experiment has been developed.The efficiency of the algorithmis shown with the help of computer simulation.

How Neutrosophic Logic may Resolve Dispute on the Origin of the Universe through re-reading Gen. 1:1-2

In recent years, the Big Bang as described by the Lambda CDM-Standard Model Cosmology has become widely accepted by majority of physics and cosmology communities. But the philosophical problems remain, as Vaas pointed out: Did the universe have a beginning or does it exist forever, i.e. is it eternal at least in relation to the past? This fundamental question was a main topic in ancient philosophy of nature and the Middle Ages, and still has its revival in modern physical cosmology both in the controversy between the big bang and steady state models some decades ago and in the contemporary attempts to explain the big bang within a quantum cosmological (vacuum fluctuation) framework. In this paper we argue that Neutrosophic Logic offers a resolution to the long standing disputes between beginning and eternity of the Universe. In other words, in this respect we agree with Vaas, i.e. it can be shown: “how a conceptual and perhaps physical solution of the temporal aspect of Immanuel Kant’s „first antinomy of pure reason“ is possible, i.e. how our universe in some respect could have both a beginning and an eternal existence. Therefore, paradoxically, there might have been a time before time or a beginning of time in time.” By the help of computational simulation, we also show how a model of early Universe with rotation can fit this new picture. Further observations are recommended.

Simulation of Continuous Markov Processes in Discrete-Time for Signals Described by Stochastic Differential Equations

We considered the issues associated with methods for solving the problems of representation of continuous Markov processes in discrete-time by the example of radar signals, which are subject to the simultaneous effect of additive and multiplicative noise described by stochastic differential equations. We considered the algorithm, which allows us to carry out computer simulation of fading amplitude, phase and information parameter of the signal in discrete observation time using the example of a continuous frequency-modulated signal, the amplitude of which adheres to the Nakagami distribution that is typical for radar signals under simultaneous effect of additive and multiplicative noise. It is shown that with the help of computer simulation it is possible to create not only optimal algorithms, but also their corresponding optimal structural diagrams, which makes it possible to elevate the processing of radar signals to higher standards.

On Implementation of Plants in the Indoor Environment in Intelligent Buildings

The article deals with the research of the influence of plants on the potential energy savings in the field of ventilation of intelligent buildings. It is known that selected plants can effectively reduce the concentration of carbon dioxide even in the indoor environment of buildings in poor lighting conditions. The paper presents a theoretical simulation method that shows the potential of selected plants to reduce the concentration of carbon dioxide in the indoor environment and thus reduce the requirement for the amount of supplied air in intelligent buildings which are air-conditioned based on the current and required concentration of carbon dioxide. The results of the research are very influential; in terms of overall percentage savings, plants have the most significant effect in buildings with lower indoor air quality (IDA4+), while they have a less significant effect in areas with high air quality according to carbon dioxide concentration (IDA2, IDA3). Research with the help of computer simulation shows that the implementation of 1 m2 of living green plants, depending on the quality class of the IDA indoor environment, can bring savings on the amount of supplied air in the range of 0.058 % to 1.997 % for a typical office for 4 people.

Inventory of pollutant emissions into the atmosphere from gas turbine installations of gas pumping units

Development of a single method for inventory of pollutant emissions from installations based on the elaboration of existing methods for calculation of air pollution is an important scientific and practical task in the field of environmental safety.
 The main purpose of the study is to test and compare models of stationary emission sources and to assess air quality based on them.
 In the inventory of pollutant emissions, the following materials are used: direct measurements, which are based on direct instrumental measurements, and calculated measurements or combinations thereof.
 According to the direct measurements of NOx and CO emissions from the operation of gas turbines at the Valley compressor station with a nominal capacity of 1 to 50 MW, we found that: the actual emissions of NO and CO increase with the average load on the installation and the time of introduction into operation and date of issue and the actual values of the maximum allowable concentration of NOx (from 100.13 to 467 mg / m) and CO (from 16.08 to 444.88 mg / m) do not exceed the permissible levels of NO-500 mg / m and CO-250 mg / m according to the instructional documents.
 Comparison of these calculation methods showed the same results, which confirms the need for their systematization with the subsequent development of a single methodology.
 The distance of 106 m, where the maximum concentration of pollution in adverse weather conditions is expected, was obtained by the calculation method of determining the surface concentration of NOx and CO emissions from the installation.
 To assess the effectiveness of the methods for inventory of pollutant emissions into the atmosphere from gas turbines, we have developed a scheme of relationship between the object being assessed for efficiency and the object being serviced. Particularly noteworthy are the results and analysis of direct measurements of NOx and CO emissions, as well as the developed scheme for linking the inventory process for pollutant emissions into the atmosphere from installations.
 The actual concentration of pollutants can be estimated by measuring the background, although in this case it is impossible to exclude the influence of other neighboring and remote emission sources on the results of the air pollution assessment. Depending on the specific task, the results of computer simulation for given parameters of the external environment can also be used to assess the actual, retrospective or prospective conditions. Future conditions can be modeled only with the help of computer simulation.
 The method of air pollutant concentration calculation for emissions of enterprises does not consider all possible features of emission sources and, in terms of passive stationary sources and cold emissions, the algorithm needs to be clarified and the justifications in the paper indicate ways to make these improvements.
 Inventory is the first stage in the strategy of air quality regulation, as it provides information for the development, justification and decision-making in regulating the activities of gas turbines to reduce adverse effects on the environment and public health.

Evaluation of the effectiveness of the use of passive resonant anti-vibrators

The effectiveness of resonant antivibrators is investigated with the help of computer simulation. The amplitude-frequency characteristics of the structure under study are presented. The developed algorithm makes it possible to evaluate and change the expected dynamic parameters of the structure in order to reduce vibrations. Keywords: resonant antivibrator, vibration damping coating, effectiveness, modeling. samokhinvs@yandex.ru

Impact of wind in the dynamics of prey–predator interactions

The interaction of the predator–prey relationship does not only rely upon the biotic factors, but various abiotic factors can also take an essential role in determining the system dynamics. Wind is an omnipresent component in the biosphere that may crucially alter the predation pattern of any species. In this article, we formulate and analyse a predator–prey model incorporating wind in the predation function. Two types of modified functional responses have been proposed to capture the overall dynamics of the associated system considering the fact that wind may either decrease or increase predation rate of predators. Positivity and boundedness of the solutions of the systems have been shown to confirm the well-posedness of the systems. Equilibrium points and their state of stability have been examined under suitable conditions of parametric restrictions. Wind is shown to change the state of stability of coexistence equilibrium point through Hopf bifurcation in particular cases. On the other hand, strength of wind flow cannot be supposed to be constant throughout a time period. Considering this fact, we further modify the functional responses taken into account periodically varying wind flow and analyse the corresponding systems with the help of computer simulation. Our analysis revealed that the impact of wind on a system dynamics has a strong interrelation with functional response. All the analytical findings have been testified numerically and the article ends with a comprehensive conclusion of our overall study.

Математические модели углового движения космических аппаратов и их использование в задачах управления ориентацией

Предложена общая структура кинематических уравнений эволюции ориентации космического аппарата (КА) (системы координат, связанной с КА (ЗСК)) относительно опорной системы координат (ОСК). Предполагается, что начала систем координат совпадают и расположены в произвольной точке КА. Каждая из систем координат оборачивается произвольной абсолютной угловой скоростью (скоростью относительно инерциального пространства), заданной проекциями на их оси. В качестве параметров ориентации могут использоваться углы Эйлера-Крылова, параметры Родрига-Гамильтона, модифицированные параметры Родри-га. Показано, что известные представления уравнений эволюции ориентации ССК относительно ОСК в параметрах Родрига-Гамильтона (компонентах нормируемых кватернионов) могут быть получены из решения задачи Н.П. Ерюгина — отыскание всего множества дифференциальных уравнений, имеющих заданный интеграл движения. Отмечены преимущества и недостатки использования каждого из указанных параметров ориентации. Предложен общий для всех этих уравнений метод синтеза управления ориентацией, основанный на декомпозиции исходной задачи на кинематическую и динамическую задачи и использовании известных обобщений прямого метода Ляпунова для их решения. С помощью компьютерного моделирования проиллюстрировано свойство структурной грубости в смысле А.А. Андронова-Л.С. Понтрягина полученного алгоритма. А именно, на конкретном примере проиллюстрирована свойство даже намеренно структурно упрощенного алгоритма стабилизации заданной постоянной ориентации КА с достаточной точностью отслеживать программу ее изменения. Задача наблюдения типична в управлении стыковкой КА, спуском КА с орбиты, выполнении маршрутных съемок поверхности Земли.

МОДЕЛИРОВАНИЕ РАБОТЫ РАЗДЕЛИТЕЛЬНЫХ КАМЕР

Introduction. Separation chambers are designed and built for separate and partially separate sewerage systems. Their main function is to separate the flow of relatively clean water during heavy rain. This allows the discharge of such water without treatment into water bodies or storage tanks. The approach reduces the load of wastewater treatment plants. To design separation chambers, we need to understand how their design features affect the process of flow separation. It is possible to study the hydraulic characteristics of separation chambers of any design with the help of computer simulation. Two designs of separation chambers were investigated: a circular spillway with a full-scale prototype and a spiral spillway proposed by the authors. Methods. The research was based on simulation in the ANSYS CFX finite element analysis software. For each design, a series of five experiments with different incoming flow rates was performed. Results. Models of two types of separation chambers were developed and qualitatively evaluated. The hydraulic characteristics were established and quantified: the uniformity of the flow discharged for treatment and the spillway discharge coefficient. Conclusion. As a result, a principled approach was formed and tested. Using this approach, it is possible to study the hydraulic characteristics of separation chambers of various designs for their further use in the sewerage system.

Nanofluidics for Gas Separation Applications: The Molecular Dynamics Simulation Perspective

ABSTRACT Since past decades, membrane science and technology have received great attention in academia and practice because of their potential for industrial applications. A diverse range of industrial applications has been benefited from this technology thanks to the advances in membrane science. Membranes are of paramount importance in chemical technology and play a key role in a broad range of applications.Membranes incorporating nanosize pores or channels have a tremendous contribution to membrane science discipline, particularly in gas separation technologies. Performing pore-level modeling with the help of computer simulation opens a route to membrane characterization in high accuracy and less observational. By utilizing molecular dynamics simulations, one can provide a fundamental understanding of the static and dynamic features of membranes at a molecular scale. In this work, we have reviewed the recent advances in nanofluidics for gas separation applications, with a major focus on the theoretical literature discussing the gas molecular transport mechanisms through the carbon-based nanopores. Describing the nanofluidics systems, solid-state nanopores, fabrication of nanofluidic devices, pore generation on graphene nanosheets, and pore-level flow modeling, this article expects to provide a platform for understanding the permeation and separation of gases across a variety of nanopores and attracting more attention of audiences from industry and academia.

Beyond Salsburg–Wood: Glass equation of state for polydisperse hard spheres

We reconstruct glass equations of state for polydisperse hard spheres with the help of computer simulations. To perform the reconstructions, we assume that hard-sphere glass equations of state have the form Zg(φ, φJ) = Zg(φJ/φ), where Zg, φ, and φJ are the reduced glass pressure (PV/NkBT), sphere volume fraction (packing density), and jamming density of the current basin of attraction, respectively. Specifically, we use the form X = ∑iciYi, where X = (φJ/φ) − 1 and Y = 1/(Zg − 1). Our reconstructions converge to the well-known Salsburg–Wood and free volume equations of state in the limit φ → φJ, but they are also applicable for values of φ ≪ φJ. We support the ansatz Zg(φ, φJ) = Zg(φJ/φ) with extensive computer simulations. We use log-normal distributions of particle radii (r) and polydispersities δ=⟨Δr2⟩/⟨r⟩=0.1−0.3 in steps of 0.05. By supplying the fluid equation of state (EOS) into the new glass EOS, we evaluate equilibrium jamming densities φEJ for a range of φ. By using the ideal glass transition densities φg as an input φ, we estimate the corresponding glass close packing limits φGCP = φEJ(φg). We use the Boublík–Mansoori–Carnahan–Starling–Leland fluid EOS, and we estimate φg from the Vogel–Fulcher–Tammann fits—but our method can work with any choice of the fluid EOS and φg estimates. We show that our glass EOS leads to much better predictions for φEJ(φ) than the standard Salsburg–Wood glass EOS.

ოთხგანზომილებიან სიგნალთა არაოპტიმალური კომბინირება

The article discusses the issue of signal transmission in channels where fading takes place along with additive white Gaussian noise. It is commonly supposed that at this time the signal amplitude (envelope) was fluctuated with the Rayleigh distribution. It is accepted that fading is slow and frequency is non-selective. For transmit diversity from antennas, their combination with signals is carried out in a selective scheme. The characteristics of systems based on 2FSK-8PSK and 2FSK 8APSK signals are evaluated with the help of computer simulation.

Визначення витратних характеристик ресивера за допомогою комп’ютерного моделювання

The problem of implementing the detonation mode of fuel combustion in thermal propulsion systems has been widely studied last decade. There are many works on fundamental and applied research on pulsating detonation. Solid propellant detonation engines can develop significant forces for a short time at low structural masses, and therefore they are ideal for auxiliary systems for the removal of separated rocket parts. In addition, detonation processes can be used to create control forces for correcting the trajectory of aircraft. All these facts determine the relevance of the area of work. For studying detonation installations, it is necessary to create test stands, but the design of test installations is an urgent and complex optimization problem. It is advisable to solve this problem with the help of computer simulation. In the existing experimental methods, for designing, it is necessary to determine in advance the geometric parameters of receivers and pipelines that provide the necessary gas consumption for firing tests of detonation rocket engines. The work is devoted to the development of a method for determining the flow characteristics of a receiver with a pipeline of complex configuration based on the constructed model of the stand. Based on the initial data, a computer simulation of the air leakage process from the receiver was carried out, for which the Solid Works software package was used. The places of pressure drop, maximum flow rate, and air mass flow are determined. The low value of the flow rate factor is due to the complex configuration of the pipeline with numerous bends and two bellows. Comparison of calculation results with experimental data was held. The difference between the experimental and calculated values does not exceed 3.6%. The obtained information is used to select the required value of the oxidizer excess coefficient during firing tests of detonation rocket engine models. Keywords: flow rate, gas leakage, receiver, model.

Recent advances in traffic optimisation: systematic literature review of modern models, methods and algorithms

Over the past few decades, the increasing number of vehicles and imperfect road traffic management have been sources of congestion in cities and reasons for deteriorating health of its inhabitants. With the help of computer simulations, transport engineers optimise and improve the capacity of city streets. However, with an enormous number of possible simulation types, it is difficult to grasp valuable, innovative solutions which are of the greatest value to city citizens. In this work, the authors expose various problems within this area having reviewed and analysed over 130 papers selected out of 1200 works in the field of urban simulations. The study describes the selection process of important papers and highlights characteristics of microsimulations, macrosimulations, computation optimisations and other approaches found in the literature which are especially useful and should be further built on in the future. They present and compare results provided in reviewed works in terms of throughput improvement, queue, waiting and travel time reduction, vehicle speed increase, speed-ups as well as assumed simulation parameters. Finally, they focus on research gaps, such as a small number of works considering crisis simulations, few real-world scale simulations as well as on software architectural changes and low-level optimizations.

WITHDRAWN: A study on single frequency network on high speed train

Abstract This paper presents a comprehensive study on millimetre wave (mmWave)-based mobile hotspot network (MHN) system for high-speed train (HST) communications, including system design, field trial, channel modeling based on measurement campaign, simulation and validation. Firstly, the physical layer specification and single frequency network (SFN) which includes MHN enhanced design (MHN-E) and the overview of the MHN system is provided. Secondly, For MHN conventional (MHN-C) and MHN-E systems, the prototypes and the overall design is presented and the MHN-C prototype and demonstrations with the MHN-E prototype are analysed with the help of results of field trial which conducted at Seoul subway line 8.Thirdly, the paper presents a characteristics of a measurement campaign investigating channel which is based on rural HST environment. Lastly, the performance of the MHNE system is validated by the help of computer simulation. The simulation is done at the speed of 500 km/h under the QuaDRiGa channel model which is also known as the good method for validation of HST communication systems, since it is impractical by real testbeds now. The simulation results revealed that with a peak data rate which exceeding 5 Gbps at a speed of 500 km/h the MHN-E system can able to provide a broadband mobile wireless backhaul (MWB).

A self-consistent dynamical system with multiple absolutely continuous invariant measures

In this paper we study a class of \emph{self-consistent dynamical systems}, self-consistent in the sense that the discrete time dynamics is different in each step depending on current statistics. The general framework admits popular examples such as coupled map systems. Motivated by an example of M. Blank, we concentrate on a special case where the dynamics in each step is a $\beta$-map with some $\beta \geq 2$. Included in the definition of $\beta$ is a parameter $\varepsilon > 0$ controlling the strength of self-consistency. We show such a self-consistent system which has a unique absolutely continuous invariant measure (acim) for $\varepsilon=0$, but at least two for any $\varepsilon > 0$. With a slight modification, we transform this system into one which produces a phase transition-like behavior: it has a unique acim for $0< \varepsilon < \varepsilon^*$, and multiple for sufficiently large values of $\varepsilon$. We discuss the stability of the invariant measures by the help of computer simulations employing the numerical representation of the self-consistent transfer operator.

Surgical workflow simulation for the design and assessment of operating room setups in orthopedic surgery

BackgroundThe design and internal layout of modern operating rooms (OR) are influencing the surgical team’s collaboration and communication, ergonomics, as well as intraoperative hygiene substantially. Yet, there is no objective method for the assessment and design of operating room setups for different surgical disciplines and intervention types available. The aim of this work is to establish an improved OR setup for common procedures in arthroplasty.MethodsWith the help of computer simulation, a method for the design and assessment of enhanced OR setups was developed. New OR setups were designed, analyzed in a computer simulation environment and evaluated in the actual intraoperative setting. Thereby, a 3D graphical simulation representation enabled the strong involvement of clinical stakeholders in all phases of the design and decision-making process of the new setup alternatives.ResultsThe implementation of improved OR setups reduces the instrument handover time between the surgeon and the scrub nurse, the travel paths of the OR team as well as shortens the procedure duration. Additionally, the ergonomics of the OR staff were improved.ConclusionThe developed simulation method was evaluated in the actual intraoperative setting and proved its benefit for the design and optimization of OR setups for different surgical intervention types. As a clinical result, enhanced setups for total knee arthroplasty and total hip arthroplasty surgeries were established in daily clinical routine and the OR efficiency was improved.

Development of synthetic open porous structures for improved heat transfer

If water pipes, which are heated from the outside, are lined with an open porous inner structure, the heat can quickly reach the water via the large contact surface. At the same time, the flow resistance increases due to the presence of the interior. We aim for computationally designing an internal structure that is advantageous for both heat transfer and flow. In this paper we present our path from digital models to metallic pipe components with specifically adjusted properties: First, we design digital models for line pipe elements and qualify them with the help of computer simulations. As a next step, the algorithmically generated samples are printed in 3D. The 3D-printed polylactide models serve as prototypes for the production of metallic pipes, which are then tested in experiments. In this work, three types of inner structures are evaluated: Metal foam, cuboid fins and curved fins. For better comparability, we provide them with almost the same specific surface area and porosity. The use of open-pore metal foams is advantageous for greater heat transfer and fins enable smaller pressure drop.