Computer Simulation Analysis Research Articles

Decision-analytic modeling as a tool for selecting optimal therapy incorporating hematopoietic stem cell transplantation in patients with hematological malignancy.

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is the only curative treatment available for various hematological malignancies. Ideally, prospective randomized controlled trials (RCTs) should establish the indications for allo-HSCT. In reality, however, RCTs are not feasible due to the rarity of many hematological conditions. In these scenarios, decision analysis, which simulates possible outcomes with different approaches, can help in selecting the treatment strategy predicted to have the best result. Assessment of cost-effectiveness can also be incorporated in computational simulation analysis. In this review, we would like to provide an overview of decision-analytic models that evaluate alternative treatment strategies for patients with hematological malignancies.

Experimental and theoretical studies of drug-polymer interactions to control the drug distributions in dissolving microneedles

Dissolving microneedles (DMNs) have attracted extensive attention for transdermal drug delivery in recent years. Generally, the skin elasticity impedes DMNs to fully insert into skin thus optimized fabrication methods are needed to improve delivery efficiency. Here, we investigated the formulations of DMNs as the main influencing factors during the microneedle preparation process. Through the selection of the matrix materials and the optimization of the ratio and formulae, the DMNs can meet the requirements of convenient and effective drug delivery. For DMNs prepared with polyvinyl alcohol (PVA) as matrix material, the 25wt% concentration of PVA was beneficial to prepare MNs, which MNs was able to focus drug on the part of MN tips. However, for DMNs fabricated with hyaluronic acid (HA), the increasing material concentration had a weaker ability to concentrate drug in MNs and increased the difficulty of preparing MNs. The computer simulation analysis was consistent with the results of the experiment, indicating the feasibility of modelling to investigate the preparation technology of DMNs that offer appropriate, convenient and highly efficient drug delivery.

ДИНАМІЧНА МОДЕЛЬ ПРИСТРОЮ ДЛЯ КЕРУВАННЯ ЗМІНАМИ ШВИДКОСТІ ІЗ ЗУБЧАСТИМ ДИФЕРЕНЦІАЛОМ І ЗАМКНУТОЮ ГІДРОСИСТЕМОЮ ЧЕРЕЗ ВОДИЛО

The purpose of the study is to build a dynamic model of the speed change device including a differential gear and a closed-loop hydraulic system, where the driving link is a sun gear driven by an electric motor, while a closed-loop hydraulic system is connected to the carrier and can change its speed due to changes in system’s throughput, the ability of the fluid to move across the hydraulic system, so that the necessary law of motion on the driven link - the ring gear can be obtained. The analysis of recent publications has revealed that the research of new speed control devices with a differential gear and a closed-loop hydraulic system through the carrier pays much attention to their structure, principle of operation, and the change in speed, that has been confirmed by analytical and graphical dependences. In addition, energy efficiency and self-braking of such devices has been studied by determining the coefficient of performance efficiency. The dynamics of such devices is waiting to be resolved. It will allow us to develop methods to reduce the impact of dynamic loads on the mechanical drives of machines when changing speed. The article proposes a mathematical model of the movement of a mechanical system for new devices for changing the speed using a differential gear with a closed-loop hydraulic system through the carrier. For this purpose, the equation of dynamics by the Lagrange method of the second kind has been used and the equation of kinetic energy of the system has been formed. Since there is a relationship between the speeds of all links in the differential gear, the expression for the kinetic energy of the system has been described by the speed of the driving and driven links, i.e., by the speed of the sun gear and the ring gear. The result of solving the Lagrange equation in partial derivatives is a system of two differential equations with unknown derivatives of the velocities of the sun gear and the ring gear. The obtained results are the basis for further computer simulation and quantitative analysis to assess the performance of such devices and select the necessary closed-loop hydraulic system to control speed changes. Based on the dynamic model, it is possible to compose and solve the equations of dynamics for typical cases of changes in the torque resistance: long-term shock, short-term shock and significant overload, up to the stop of the machine.

Effect of reheating zones in additive manufacturing by means of electron beam metal wire deposition method

The influence of heat transfer on molten pool size and temperature during the additive metal wire deposition process is shown. A mathematical model based on an energy equation that considers latent heat during melting is proposed. The model also examines the temperature dependences of thermophysical properties and the results are presented graphically. The analysis of computer simulation results reveals a gradual increase in molten pool size during deposition of a hollow cylindrical shape due to the influence of reheating zones. The results of experimental studies (conducted on ELA-40I and AELTK-12 electron beam installations) that confirm the simulation results are presented. Both sets of results suggest the need for feedback in order to control the molten pool temperature. As such, the proposed model is used to conduct a study involving temperature feedback. The analysis of time dependences obtained via simulation shows the fundamental possibility of stabilizing the temperature at a desired point. Limitations and possible improvements to this method are explored.

Analysis of the Damage of Cyclists in Electric Bicycle - Sedan Angle Collision

In order to study the vulnerable factors of the traffic accidents—the cyclist's injury factor at the moment of the accident—the computer simulation analysis method is used to restore the information collected by a real accident combined with the scene. From the established multi-rigid kinematics model, the corresponding injury situation of a body structure of a traffic accident rider is obtained, which involves the collision speed, the collision angle, the acceleration of each part of the human body and the force. The data is compared with ECE R44, FMVSS 213 and Euro NCAP 2009 regulations to analyze and restore various factors of bicycle injury in the collision. The results show that when the car and the non-motor vehicle have a low-angle collision, the cyclist's injury is mainly caused by the collision with the ground after the parabola movement, and the damage position of the human body depends on the order of contact with the ground.

Joint multiple quantitative trait loci mapping for allometries of body compositions and metabolic traits to body weights in broiler

In order to map quantitative trait loci (QTLs) for allometries of body compositions and metabolic traits in chicken, we phenotypically characterize the allometric growths of multiple body components and metabolic traits relative to BWs using joint allometric scaling models and then establish random regression models (RRMs) to fit genetic effects of markers and minor polygenes derived from the pedigree on the allometric scalings. Prior to statistically inferring the QTLs for the allometric scalings by solving the RRMs, the LASSO technique is adopted to rapidly shrink most of marker genetic effects to zero. Computer simulation analysis confirms the reliability and adaptability of the so-called LASSO-RRM mapping method. In the F2 population constructed by multiple families, we formulate two joint allometric scaling models of body compositions and metabolic traits, in which six of nine body compositions are tested as significant, while six of eight metabolic traits are as significant. For body compositions, a total of 14 QTLs, of which 9 dominant, were detected to be associated with the allometric scalings of drumstick, fat, heart, shank, liver and spleen to BWs; while for metabolic traits, a total of 19 QTLs also including 9 dominant be responsible for the allometries of T4, IGFI, IGFII, GLC, INS, IGR to BWs. The detectable QTLs or highly linked markers can be used to regulate relative growths of the body components and metabolic traits to BWs in marker-assisted breeding of chickens.

Virtual Realism: Really Realism or only Virtually so? A Comment on D. J. Chalmers’s Petrus Hispanus Lectures

Abstract What is the status of a cat in a virtual reality environment? Is it a real object? Or part of a fiction? Virtual realism, as defended by D. J. Chalmers, takes it to be a virtual object that really exists, that has properties and is involved in real events. His preferred specification of virtual realism identifies the cat with a digital object. The project of this paper is to use a comparison between virtual reality environments and scientific computer simulations to critically engage with Chalmers’s position. I first argue that, if it is sound, his virtual realism should also be applied to objects that figure in scientific computer simulations, e.g. to simulated galaxies. This leads to a slippery slope because it implies an unreasonable proliferation of digital objects. A philosophical analysis of scientific computer simulations suggests an alternative picture: The cat and the galaxies are parts of fictional models for which the computer provides model descriptions. This result motivates a deeper analysis of the way in which Chalmers builds up his realism. I argue that he buys realism too cheap. For instance, he does not really specify what virtual objects are supposed to be. As a result, rhetoric aside, his virtual realism isn’t far from a sort of fictionalism.

Experimental analysis on Generic principles for developing Robust Designs against Casting Defects

The world is running around invention and advancements in the existing products or components, and this wasn’t be easy without design concepts and its principles. This paper is conferring on this facet, how the design can be made robust against manufacturing flaws by varying the parameters such as material properties, dimensions, shapes etc. If a design engineer compels a mistake while designing a product, results in the following aspects: confidence, business, customers, sales, servicers, repute etc. If we modify the design, and make it robust, some or all of these losses will be recouped., It is not an easy task to discuss all manufacturing capabilities in one go , to have a lucidity in the concept the flaws of manufacturing during casting were focused in this paper. Based on the theoretical study and experiment analysis conducted on a casting “+” model the results are outlined. Based on the output, a list of generic design principles was defined, which can be considered by a design engineer during casting design process. The paper starts with a brief introduction to robust design, followed by a literature review, then design solutions, computer simulation analysis of a casting component (using Solid Works) and finally the conclusions made from the results.

Structure and Hybridization Properties of Glycine Morpholine Oligomers in Complexes with DNA and RNA: Experimental and Molecular Dynamics Studies.

Methylenecarboxamide (glycine) morpholine oligomers (gMOs) with a modified backbone are new and promising nucleic acid analogues. In this work, a combination of circular dichroism spectroscopy, optical melting, and molecular dynamics simulations was used to investigate hybridization properties of gMOs, as well as the structure and dynamics of their tandem complexes with DNA and RNA. It was shown that the structure of nucleic acids in modified complexes is similar to that of the fully native analogues. The energies of binding and cooperative interactions at the helix-helix interface in the nick were determined experimentally and by computer simulation analysis. Here, we found for the first time, the possibility to determine and predict precisely the thermodynamic parameters of complementary complex formation using the original experimental and computer simulation approaches. It was shown that the use of simulation data in the explicit solvent and the molecular mechanics Poisson-Boltzmann (or generalized Born) surface area methods for the calculation of the hybridization enthalpy makes it possible to evaluate the thermal stability of DNA and gMO tandem duplexes with DNA or RNA with an unexpectedly high accuracy. We found that at high ionic strength and neutral pH, the observed thermal stability of the gMO/RNA tandem complex is similar to that of DNA/DNA and lower than that of gMO/DNA which is close to that of DNA/RNA.

Spectrum-Efficient Resource Allocation in Multi-Radio Multi-Hop Cognitive Radio Networks.

The multi-hop cognitive radio network (CRN) has attracted much attention in industry and academia because of its seamless wireless coverage by forming multi-hop links and high spectrum utilization of cognitive radio (CR) technology. Using multi-slot statistical spectrum status information (SSI), this work investigates the average spectrum efficiency (SE) of a multi-radio multi-hop (MRMH) CRN where each hop is permitted to use different spectra and long-distance hops can reuse the same idle primary user (PU) spectrum. Faced with the modeled SE problem, which is a complex non-convex fractional mixed integer nonlinear programming (MINLP) problem, the optimal spectrum and power allocation for multi-hop links in multi-slot and multi-channel scenarios can be obtained with the proposed successive multi-step convex approximation scheme (SMCA). As shown through computational complexity and simulation analysis, SMCA can obtain an approximate lower bound of the optimal solution for the modeled SE problem with a lower computational cost. Furthermore, some potential relationships between network performance and spectrum idle rate can be easily discussed with SMCA, which can provide some sensible deployment strategies for the MRMH CRN in future multi-slot scenarios.

Simulation Analysis of Exothermic Powder in Riser Area on Inner Quality of Steel Ingot

15t steel ingots of different amount of exothermic powder were under computer simulation analysis by casting simulation software with the distribution of shrinkage cavity predicted. The results showed that, with increasing adding of exothermic powder, the final solidification high temperature area moves from the main body of the ingot onto the riser area, so that the riser can feed the shrinkage cavity very well. The simulation result agrees with validation experiments very well. It indicates that the optimized adding suitable amount of exothermic powder in riser area can effectively eliminate the shrinkage cavity, and enhance the steel ingots’ quality and the ration of utilization.

Investigation on one-step integrated positioning method for seafloor control network localization

Global Navigation Satellite System-Acoustic (GNSS-A) combined positioning is the main technique for seafloor geodetic control points localization, typically including datum transfer and subsequent positioning adjustment. This conventional step-wise method is time-consuming and accuracy-limited. In this paper, a novel one-step integrated positioning method for seafloor control network localization is proposed, which estimates positions of surveying vessels and seafloor points simultaneously. The effectiveness of new method is verified by computer simulation and comparative analysis. First, the conventional underwater acoustic positioning stepwise adjustment method is introduced and the positioning errors are analyzed. Then, to better constrain positions, the baseline lengths and depth-differences between pair of seafloor transponders are taken into consideration. The novel integrated positioning model based on overall adjustment is established. Furthermore, to deal with rank deficiency problem in overall adjustment, selecting weight fitting (SWF) method is applied in consideration of reliable priori information of surveying vessel coordinates. Finally, the regulating parameter determination for SWF method is discussed. Tests demonstrate that depth-differences constraint performs better than baseline length constraint in light of vertical geometry weakness. The novel method is notably superior to the conventional method in terms of positioning accuracy according to rms (Root Mean Square) statistics.

Computational fluid dynamics simulation and experimental analysis of ultrafine powder suspension

The suspension characteristics of ultrafine powder slurry in the stirred vessel were simulated by using computational fluid dynamics. The results show that the Rushton disk turbine impeller is more conducive to maintaining suspended homogeneity and circulation of slurry compared with the pitch blade turbine pumping up impeller and the pitch blade turbine pumping down impeller. And the increase in stirring speed enhances turbulent fluctuation and anisotropic velocity of the fluid at the cost of more power consumption, which improves dispersibility and suspensibility of the particles. Meanwhile, the change of impeller clearance has a weak influence on the flow pattern, and the impeller clearance of 0.32T (T is the diameter of the bottom of the reactor) can achieve better dispersivity and suspensibility of the particles with lower power consumption and larger axial velocity. The experiments of surface coating modification of ultrafine titanium dioxide (TiO2) were carried out under the same conditions for those of the simulation system. The surface film morphology and photocatalytic properties of the modified TiO2 were analyzed, and the obtained data are well consistent with the simulation results.

Research on design method of Hy–Vo silent chain system for multi-phase transmission

Based on the meshing theory of silent chain, a new type of silent chain transmission system, the multi-phase Hy-Vo silent chain transmission system is proposed. The calculation method of the involute tooth profile equation for each phase sprocket is presented. The meshing design system is built. The Fourier series of lateral fluctuation quantity is established. The rationality of design and calculation is verified by computer simulation analysis. Compared with single-phase and double-phase silent chains, the polygonal effect of multi-phase Hy-Vo silent chain transmission system is smaller. It could provide a theoretical basis for the multivariate variation of silent chain.Communicated by John McPhee.

Facility Layout Problem By Integration of AHP and computer simulation with DEA

The facility layout problem (FLP) is concerned with finding the optimal facility arrangement in the existing layout. A layout generation and its evaluation are often challenging and time consuming due to their inherent multiple objectives in nature and their data collection process. This paper aims to propose an integrated approach of fuzzy analytic hierarchy process (AHP), computer simulation and data envelopment analysis (DEA) for facility layout design improvement and optimisation. Computer simulation is used to determine quantitative measures. AHP is used to determine first, the weight of qualitative measures for layout alternatives and second, their qualitative measures. DEA is performed by employing total cost and wait time as the input variables, accessibility and flexibility as the output variables to evaluate different layouts. Then, the alternative layouts are ranked by solving the super-efficiency DEA model for the layouts. The results imply that the proposed methodology is more reliable compared to the existing approaches.

A new charge structure based on computer modeling and simulation analysis

This paper proposes a new charge structure, which can form a penetrator with enhanced lateral effect (PELE) or explosively formed projectile (EFP) by different initiation modes. The purpose of this paper is to study the dynamic response and aftereffect of the charge liner under explosive load in PELE mode. To this end, the computer modeling and simulation analysis method was used to simulate the forming and penetrating target progress of the PELE formed by charge liner. The results indicated that the ANSYS/LS-DYNA finite element software could accurately simulate the formation of PELE and the damage process to the target, and we could obtain exact forming and damage data by this method. The PELE damage element could be formed by the new charge structure liner under explosive load, its velocity was 2050 m/s, the head-to-tail velocity gradient was only 20 m/s, the length of damage element was 63.62 mm, and the length-diameter ratio was 1.79. And PELE damage element could effectively damage 15 mm target, the inlet opening hole diameter of the target was measured to be 68 mm, the outlet diameter was 72 mm. This finding could serve a technical basis for computer modeling and simulation technology of charge structure.

Estimated remaining fatigue life of flexible pavements based on the normalized comprehensive area ratio deflection parameter

A lot of pavement deflection data are available that may be utilized as a tool to evaluate the structural capacity of pavement structures at network and project levels. Falling weight deflectometer (FWD) is one of the most widely utilized devices in pavement deflection testing. Under FWD testing, deflections generated at several lateral locations as a result of surface loading application are recorded. One of the major downsides of the static FWD testing is the traffic disturbance due to the required lane closures during testing. As an effort to reduce the amount of the required FWD testing on the network level, this study aims to run an advanced computer simulation analysis to mimic the FWD deflection bowl obtained from the field. The entire simulated FWD deflection bowl was utilized in the development of the new comprehensive pavement deflection bowl area parameters. The tensile strain at the bottom of the asphalt layer was successfully related to the developed normalized comprehensive area ratio parameter ([Formula: see text]) and to the number of load repetitions to fatigue failure. The newly developed parameter was evaluated utilizing data for 35 long term pavement performance sections in Texas. The newly developed [Formula: see text] can be easily implemented and utilized as a tool in any pavement management systems.

The Computer Simulation and Verification Analysis of Fire Scene

It is the most direct way to study fire cases through the actual fire. Therefore, if the process of fire can be reconstructed and quantified, we can not only more realize the actual action of the fire but also enhance the practicability of fire prevention. The research discusses an actual fire event of a residence in Chiayi County, Taiwan. The case was an arson attack with gasoline, and it caused the tragedy of 3 deaths and 1 severe injury. This research applies FDS (Fire Dynamics Simulator) developed from NIST to numerical simulation of the fire, makes proper assumptions under the fire description and program limitations, uses qualitative and quantitative methods for restoring and verifying the fire scene, and discusses the distribution of the temperature. Analytical result of this research could be served as the references for fire prevention engineering.

Application and Analysis of Computer Simulation in Machining Process

s. Computer simulation technology is one of the key technologies in computer simulation industry. It is widely used in the world and is one of the key technologies in global competition. The application of computer simulation technology in mechanical processing can effectively improve the accuracy and efficiency of machining, and its value is prominent. In this paper, the general situation of simulation technology will be introduced as a starting point, and the specific application of this technology in the process of mechanical processing will be discussed comprehensively. The purpose is to improve the application level of computer simulation technology and ensure the overall quality of domestic mechanical processing.

Elongated hexagonal ZnO micro-fence optical resonator

A highly symmetric ZnO micro-fence is prepared to form an optical resonator, which a symmetric array consisting of six elongated hexagonal microcolumns. It is found that the luminescence emission could be enhanced at the edge of ZnO micro-fence and the wavelength dependent light intensity could be influenced by its geometry. The optical characterization along with theoretical calculations and computer simulation analysis suggest that the Fabry-Perot and Cross-whispering gallery modes are generated in ZnO micro-fence. The individual ZnO micro-fence can regarded as an optical resonator structure. Furthermore, it is proposed that the source concentration around the substrate during the growth is a crucial factor for forming such a micro-fence.