Numerical Computer Model Research Articles

IoMT-Based Association Rule Mining for the Prediction of Human Protein Complexes

The inspiring increase in the Internet-enabling devices has influenced health industry due to the nature of these devices where they offer health related information swiftly. One of the prominent characteristics of these devices is to provide physicians with effective diagnosis of sensitive diseases. Internet of Medical Things (IoMT) is a means of connecting medical devices to computing nodes with the help of Internet for affording real-time communications between patients and clinicians to understand the interaction of human protein complexes. A secure and correct protein complex prediction plays an important job in perceiving the principal method of various cellular determinations and to elucidate the functionality of different un-annotated proteins. Different experimental schemes have been evolved to accomplish this task, however, these schemes have high error rates and are not efficient in terms of time, cost, privacy, and security. To tackle these limitations, numerous computational models have been developed that consider a protein complex as a dense sub-graph and utilize some basic topological properties such as density and degree statistics as a feature set for protein complex prediction. Different kinds of sub-graph structures, e.g., ring, star, linear, and hybrid have also been found in Protein-Protein Interaction Network (PPIN), therefore, more advance topological properties may be helpful to predict these structures. Moreover, the amino acid sequence of protein determines its formation, thus, the sequence information is important for predicting the interacting property among proteins in a secure way. In this study, we have computed basic as well as advance topological features by considering the interaction network of human protein complexes in the IoMT environment. In addition, biological features, i.e., discrete wavelet coefficients, length, and entropy from amino acid sequences of proteins have been computed. The supervised learning method based on association rules such as Partial Tree (PART) and Non-Nested Generalized Exemplars (NNGE) are trained to identify human protein complexes on the basis of integrated topological and biological properties. The 10-fold cross validation is exercised to measure the proposed methods. Experimental results show that association rule learners with integrated features outperform other complex mining algorithms, i.e., probabilistic Bayesian Network (BN), and Random Forest, in terms of accuracy and efficiency in addition to provide privacy.

PREDICTION OF GEOMECHANICAL STATE OF STABILIZED SOIL FOUNDATION OF MINE ENGINEERING BUILDING

Purpose: Prediction of geomechanical state of soft-soil foundation of buildings before and after compaction, reinforcement or stabilization. Calculation of parameters of pressure injec-tion while stabilizing the soft man-made soil foundation, development of recommendations for parameter adjustment of pressure injection.Methods: Numerical methods and computer mod-eling of the soil foundation using the finite element method for studying its geomechanical state of a mining building with regard to heterogeneities of the local geological structure and changes in the physical and mechanical properties of soils.Research findings: The obtained results are based on engineering and geological surveys of the soil foundation of the mining building composed of man-made bulk soils. The stress-strain state of the soil foundation is simulated. As a result of injection compaction the geomechanical state of the soil mass chang-es.Practical implications: Recommendations are given for the parameter adjustment of the injection method. It is shown that the pressure injection method is undoubtedly effective for the soil stabilization for buildings.

Distribution linguistic preference relations with incomplete symbolic proportions for group decision making

Distribution linguistic preference relations (DLPRs) with complete symbolic proportions have been recently investigated to record the comparison information coming from decision makers (DMs) in the context of linguistic decisions. Due to various reasons such as a lack of experience and partial knowledge about the pairs of decision alternatives, it is not always easy for DMs to provide complete symbolic proportions in DLPRs. In this paper, we propose a new style of pairwise comparison called DLPR with incomplete symbolic proportions to represent DMs’ comparison information. Two aggregation operators for DLPRs with incomplete symbolic proportions and their desirable properties are presented. An expectation-based numerical preference relation (EBNPR) is deduced from a DLPR with incomplete symbolic proportions using numerical scale models. The consistency of DLPR with incomplete symbolic proportions is defined via its associated EBNPR. On the other hand, solving linguistic decision problems implies the need for invoking the principles of computing with words (CW). The key point about CW is that words might exhibit different meaning for different people. Hence, another aim of this paper is to deal with the point about CW by setting personalized numerical scales of linguistic terms for different DMs in group decision making (GDM) with the newly introduced preference relations. Several numerical scale computation models are developed to personalize numerical scales for each DM to show their individual difference in understanding the meaning of words. Finally, we present the applications of the aforesaid theoretical results to GDM situations, which are demonstrated by solving a GDM problem of evaluating and selecting research projects.

Thermal management of edge-cooled 1 kW portable proton exchange membrane fuel cell stack

Comprehensive numerical analyses are conducted to study the influence of thermal management on performance of 1 kW edge-cooled proton exchange membrane fuel cell stack without external humidification. The experimental stack and numerical three-dimensional computational fluid dynamics model are characterized by several novelty aspects. Two numerical approaches are considered and compared for a prescribed load profile: (i) lumped model and novel (ii) real-time transient computational fluid dynamics model incorporating realistic modeling of forced air convection on the edge-cooling of the stack. The novelty of the developed computational fluid dynamics model is the capability to give insight in the transient results in only a fraction of time vs. experimental testing (40 min vs. 4 h) and other computational fluid dynamics models of fuel cells which are only capable of steady-state analysis. The developed computational fluid dynamics model is used to study the influence of (i) bipolar plate materials (ii) operating delta pressure along the flow field and (iii) different cooling fin configurations on the water and heat balance inside the stack. The results indicate that (i) maximal and average temperatures of the stack are almost linearly correlated to the thermal conductivity of bipolar plate materials and maximal temperatures can be significantly higher (ii) the operating delta pressure can be manipulated to increase the performance of the stack and (iii) the cooling fin redesign has major influence on the overall temperature uniformity across the stack. Additionally, the heat transfer between the stack and metal hydride tank is studied.

The mystery of coconut overturns the crashworthiness design of composite materials

The natural structures inspires human beings to find a new composite material design for the crashworthiness. The mystery of outstanding crashworthiness of a coconut is revealed in its multilayered and multiscale structure, including the macroscopically organized pericarp and microscopically disordered mesocarp. The pericarp consists of parallel fibers well-aligned in the tangential direction. The fibers of coconut pericarp is macro ordered. The mesocarp is the thickest layer among three layers of the pericarp. The coconut mesocarp is micro disorderly. In this paper, the coconut free drop experiments and quasi-static experiments were carried out, and the theoretical analysis was carried out to explain the natural rule of the coconut fiber arrangement, and finally the numerical computational model was built to validate the theoretical analysis. This work shows that the bottom part of the coconut is the impact point to the ground during the free drop experiments without initial angel. The fiber orientation in the coconut fruit can increase the energy absorption ability, and such a fiber arrangement can influence the propagation of the stress wave to protect the coconut endocarp. A bio-inspired template has been provided for the functionally gradient composite material design.

Numerical investigation of surface wettability on gas – Liquid flow hydrodynamics in microchannel: Application to trickle bed reactors

Two-phase gas-liquid flows are very important in trickle bed catalytic reactors. To investigate the effect of catalyst wettability on the two-phase flow hydrodynamics in the bed, microchannels are considered in order to simulate the pore scale phenomena. Since the surface area to volume ratio is a key factor at the microscale, the role of surface interaction becomes dominant. In this work, the channel hydrophobicity is varied in order to study the effect of the wetting properties of a rectangular horizontal micro-channel on the gas-liquid two-phase flow behavior. Air and water are injected through a Y junction microchannel where water is injected in the middle and air from side inlets, to investigate the air/water two-phase flow behavior in the straight section. The surface wettability of two types of catalysts is experimentally measured and used as input to the numerical computational model. The microchannel is of 300 μm, 100 μm and 1 cm in width, height and length, respectively. The CFD simulation is done on COMSOL Multiphysics, using the Level Set method. The level-set technique is used to represent a discrete fluid interface between the two phases. Navier Stokes equations and conservation of mass, coupled to the level set method keep track of the interface between the air and water in the flow field, including the interfacial interactions with the microchannel walls. The developed numerical model is used to characterize the hydrodynamics of cocurrent gas—liquid flow through the microchannel. The model was validated against published experimental data and good agreements are obtained. The prediction results demonstrate that the wetting properties of the microchannel affect drastically the two-phase flow hydrodynamic behaviors. We identified eight different flow patterns in the hydrophobic microchannel, whereas, in the case of hydrophilic microchannel, only two flow patterns were observed. All of these results were in good agreement with published experimental ones. The developed numerical model was thus used to predict trickle bed flow hydrodynamics at the microscale.

Effects of Cross-Clamping on Vascular Mechanics: Comparing Waveform Analysis With a Numerical Model

BackgroundImmediate changes in vascular mechanics during aortic cross-clamping remain widely unknown. By using a numerical model of the arterial network, vascular compliance and resistance can be estimated and the time constant of pressure waves can be calculated and compared with results from the classic arterial waveform analysis. MethodsExperimental data were registered from continuous invasive radial artery pressure measurements from 11 patients undergoing vascular surgery. A stable set of beats were chosen immediately before and after each clamping event. Through the arterial waveform analysis, the time constant was calculated for each individual beat and for a mean beat of each condition as to compare with numerical simulations. Overall proportional changes in resistance and compliance during clamping and unclamping were calculated using the numerical model. ResultsArterial waveform analysis of individual beats indicated a significant 10% median reduction in the time constant after clamping, and a significant 17% median increase in the time constant after unclamping. There was a positive correlation between waveform analysis and numerical values of the time constant, which was moderate (ρ = 0.51; P = 0.01486) during clamping and strong (ρ = 0.77; P ≤ 0.0001) during unclamping. After clamping, there was a significant 16% increase in the mean resistance and a significant 23% decrease in the mean compliance. After unclamping, there was a significant 19% decrease in the mean resistance and a significant 56% increase in the mean compliance. ConclusionsThere are significant hemodynamic changes in vascular compliance and resistance during aortic clamping and unclamping. Numerical computer models can add information on the mechanisms of injury due to aortic clamping.

Numerical computational modeling of random rough sea surface based on JONSWAP spectrum and Donelan directional function

SummaryIn this paper, 51 sets of directional spectrum measured data collected from the Bohai offshore site were applied to study the comparative characteristics of Wen's direction spectrum and Donelan direction function. Firstly, the optimal frequency value of direction spectrum is analyzed from two aspects: the direction cumulative distribution and the direction distribution function fitting quality. Secondly, combined with the experimental results, the distribution characteristics of different direction functions are compared from the maximum and standard deviation of the distribution function. The experiments prove that Donelan function contains all the states of the wind and wave growth stage, which can fully measure the influence of the wave age on wind frequency spectrum. Then, this paper analyzes the classical Monte Carlo method and the Las Vegas method from the perspective of the computational complexity and direction distribution difference of simulation step. Based on the classical Monte Carlo method, this paper proposes a two‐dimensional random rough sea surface numerical calculation model suitable for different water depths and different wind wave growth stages. Finally, by analyzing the characteristics of the nonlinear sea surface, this paper studies the effects of wind speed, wind direction, and fetch on sea surface wave height and growth state.

Analysis of dynamic characteristics and seismic performance for Shengshousi Pagoda

To study the dynamic characteristics and seismic performance of the Shengshousi Pagoda, the present status preserved of the pagoda’s structure was investigated on site, and the numerical computation model was established based on the parameters determined by calculated value of the natural vibration frequency of the structure. The responses of acceleration, displacement, story drift and stress were analyzed under three-way seismic wave. The seismic performance of pagoda structure was evaluated according to the calculation results of displacement and stress, and the failure criterion of pagoda materials. The results indicate that the natural frequencies in the east-west are close to that in north-south. The response laws of acceleration, displacement and stress are similar under three-way seismic wave of 8-degree fortification earthquake. Under the frequent earthquakes, the structure of pagoda does not suffer from compression damage; the tensile damage area is located at the bottom floor. Under the fortification and rare earthquakes, significant compression damage area is located at lower floors of the ancient pagoda, the stress concentration occurs around the part of opening, and significant tensile damage occurs.

Modelling and Efficiency Analysis of InGaP/GaAs Single Junction PV cells with BSF

The purposes of PV cells are to transfer light energy into electrical energy. A compelling BSF is a key basic component for a productive PV cell.. In this paper, two significant materials GaAs and InGaP with top BSF and base BSF cells are researched utilizing the computational numerical modelling TCAD tool based Silvaco ATLAS. Past research observed that on the current coordinating condition with top BSF layer and base BSF layer, the cell show a general upgrade of density in Isc (short circuit current ) and Voc (open circuit voltage ) subsequently improving the overall efficiency of the cell. In this paper, structure of various thin film PV cells based on III-V materials e.g. GaN, InGaN have been used to design the multi junction PV cells. Extraction of figures of merits (efficiency, open circuit OC voltage, short circuit SC current and fill factor), simulation of electrical and optical characteristics of these devices have been carried out in this work. Our focus is to improve the optical characteristics, refractive index and absorption coefficient of InGaP with BSF and tunnelling features. In this paper complete Simulation and experimental results are shown and compared. The objective of this paper is to examine the productivity of InGaP/GaAs PV cells utilizing the Silvaco Atlas TCAD simulation software.

Self-Assessment of experimental and numerical computer models developed at CISMID based on a bench-mark model developed in Japan at 1994

This article reports the state-of-the-art of the implementation of finite element modeling for clay masonry walls under lateral loads. Important work had been developed at CIMID Laboratory of Structures in clay walls under lateral loads and, according to the review, nowadays, researches mainly report experimental tests with their numerical nonlinear models. This process is important to validate and complement their results. Bench-mark model developed in 1994 at Chiba University had been selected to evaluate all work developed at CISMID in these recently years. The evaluation uses three variables: 1) The study evaluated include experimental results for masonry walls, (2) The study evaluated use nonlinear models for interaction between mortar and bricks, and (3) The study evaluated record their results with graphics showing the failure process. Finally, evaluate these models with finite elements demand high costs because the hardware and software requirements. However, the acquisition of a computer for High Performance Computing is necessary to afford this kind of research.

Mesoscale Shape Memory Alloy Actuator for Visual Clarity of Surgical Cameras in Minimally Invasive Robotic Surgery

This paper proposes a mesoscale shape memory alloy (SMA) actuator for cleaning the contaminated lenses of surgical cameras during minimally invasive robotic surgery. The proposed design features minimal intraopertive interruption to maintain visual clarity of fully insertable surgical cameras by quickly removing vapor condensation, particle debris, body fluids, etc. that adhere to the cover lenses. Inspired by the mechanical properties of 1-D SMA materials, a set of SMA wires are employed to drive an eyelid wiper that is concealed in the module’s edge. By analyzing the actuation mechanism, we provide a design guideline for developing a functional modular actuator. A numerical computation model is also proposed to predict the actuation cycles according to various combinations of design parameters. The performance of an initial prototype is experimentally evaluated by introducing three different contamination sources, i.e., fogging, bone dusts, and blood. The predicted actuation cycle is experimentally validated with 95.2% prediction accuracy. And the actuation cycle of the eyelid wiper is about 2 s.

Effective thrust bearing model for simulations of transient rotor dynamics

The paper introduces a new fast combined analytical and numerical computation model of thrust bearing, which can be applied to analyse the transient rotor dynamics of rotating machines. The bearing model is designed to allow an efficient solution to long-term processes while retaining its high-level capability to describe the bearing dynamics and tribology. The model includes the effects of lubricant inlet temperature and pressure and also effects of temperature, shear rate and inertia of the bearing lubricant layer. This bearing model used in the virtual turbocharger allows detailed analysis of both the design of the bearing itself and the vibration and noise issues of the turbocharger. The results obtained through the bearing model are verified using Computational Fluid Dynamics (CFD) and by technical experiments on real exhaust gas turbochargers.

Distinctive Signatures of the Spin- and Momentum-Forbidden Dark Exciton States in the Photoluminescence of Strained WSe2 Monolayers under Thermalization.

With both spin and valley degrees of freedom, the low-lying excitonic spectra of photoexcited transition-metal dichalcogenide monolayers (TMDC-MLs) are featured by rich fine structures, comprising the intravalley bright exciton states as well as various intra- and intervalley dark ones. The latter states can be classified as those of the spin- and momentum-forbidden dark excitons according to the violated optical selection rules. Because of their optical invisibility, these two types of the dark states are in principle hardly observed and even distinguished in conventional spectroscopies although their impacts on the optical and dynamical properties of TMDC-MLs have been well noticed. In this Letter, we present a theoretical and computational investigation of the exciton fine structures and the temperature-dependent photoluminescence spectra of strained tungsten diselenide monolayers (WSe2-MLs) where the intravalley spin-forbidden dark exciton lies in the lowest exciton states and other momentum-forbidden states are in the higher energies that are tunable by external stress. The numerical computations are carried out by solving the Bethe-Salpeter equation for an exciton in a WSe2-ML under the stress-control in the tight-binding scheme established from the first principle computation in the density functional theory. According to the numerical computation and supportive model analysis, we reveal the distinctive signatures of the spin- and momentum-forbidden exciton states of strained WSe2-MLs in the temperature-dependent photoluminescences and present the guiding principle to infer the relative energetic locations of the two types of dark excitons.

Downwind flow behaviours of cuboid-shaped obstacles: modelling and experiments

Buildings or fence-like structures are frequently modelled as cuboids in simulations of environmental assessments. Understanding flows around and downwind of typical isolated buildings, in the form of cuboids, provide insightful building disposition strategies, which are particularly useful in the field of urban planning. Fast analytical models or computational numerical models are essential for sensitivity studies of various design parameters that require validation against field/experimental data. The aim of this study is to compare in detail the robustness of analytical perturbation models and the computational fluid dynamics (CFD) k − ε turbulence models for predicting the mean wake velocity defects along the centre line downwind of the cuboids, both in the near- and far-wake regions. Depending on aspect ratios of cuboids, the decay rate of maximum velocity defect behaves differently. Moreover, the CFD code over-predicts the magnitude of maximum defect in comparison with the perturbation models, whereas it over-predicts or under-predicts when compared to actual measurements. A physical explanation has been proposed in this paper. The steady CFD models, requiring less empirical input, are shown to provide satisfactory results for approximate computations of flows in the near- and far-wake regions of cuboid buildings with appropriate settings of inflow profiles and wall function.

Convection of thermoviscouse fluid in a cell heated from the side

The work is devoted to the peculiarities of free-convective flow of liquids with viscosity temperature anomaly (the presence of extremes on the viscosity curve). Examples of such liquids are polymer solutions, metal melts, well-purified liquid sulfur, and other fluids. The mechanism of the anomalous viscosity behavior of such liquids (in the case of polymers) can be explained by polymerization and depolymerization reactions. At a certain temperature interval, the molecules of a substance interlock, forming long chains and, as a result, increasing the viscosity, then when the upper limit polymerization temperature is reached, the reaction begins that is reverse to the polymerization, which proceeds according to the chain mechanism and results in the sequential cleavage of molecules from the chain and leads to a decrease in viscosity . The features of behavior of such environments are currently not well understood and require increased attention to experimental and theoretical studies, especially now, mainly due to the intensive development of computer technologies and numerical modeling. Based on computational experiments on the process of free convection of a liquid with a Gaussian dependence of viscosity on temperature, the possibility of the existence of isolated regimes of convection of a liquid in a square cell heated from the side is shown. It was assumed that the viscosity function has one extremum and is unambiguously described by two parameters: the ratio of the highest to the lowest viscosity at a given temperature range and the degree of fullness of a given temperature range. As a mathematical model, a system of equations was used in the Oberbeck–Boussinesq approximation. For the numerical solution of the system of equations, the control volume method with the SIMPLE procedure is modified and implemented.

Is Primary Fixation with the Sliding Hip Screw Introduced into the Non-ideal Position Sufficient for Stable Pertrochanteric Fracture Stabilisation? A Biomechanical Evaluation and Experimental Study

Purpose: Proximal femoral fractures are most commonly sustained fractures in the elderly. The one of the current treatment option of stable pertrochanteric fracture is Sliding Hip Screw. The necessity of a repeat surgery, due to the failure of the first osteosynthesis, may jeopardize the patient's life. Common causes of a failure include: fracture pattern, implant position, implant's properties and the bone quality. Each screw position variant results in damage to various load-bearing bone structures during healing. The aim of this study was analysis of different screw positions with focuse on the risky position with the need of the intra-operative implant reintroduction.Methods: With the use of a numerical computational model and finite element methods, the authors analyzed five positions of Sliding Hip Screw in the proximal femur, with the objective of determining positions with an increased risk of failure. The ideal position was in the middle third of the femoral neck anchored subchondrally.Results: In model situations, it has been shown that in stable fractures the screw position in proximal third of the femoral neck significantly increased the strain of the plate and screw and may lead to the osteosynthesis failure. The other analysed positions do not significantly increase the risk of failure for entire fixation. Conclusions: It is not necessary to re-introduce Sliding Hip Screw into the ideal position (except placening in the proximal third of the neck) during the surgery. Damage to load-bearing structures relative to various implant placements does not impact the resultant overall fixation stability.

Analysis of underwater gas release and dispersion behavior to assess subsea safety risk.

Underwater gas release and dispersion characteristics are important to assess and manage potential risks. This paper presents an experimental and numerical investigation of underwater gas release and dispersion behavior. A small-scale experimental setup is designed and developed for underwater gas release and dispersion study. A series of release scenarios are carried out to study the effect of release size, leak pressure, and leak direction on dispersion behavior. The underwater gas dispersion behavior is analyzed from the risk assessment perspective. The considered parameters included plume offset, plume radius and fountain height for different scenarios. The experimental results are used to test and verify numerical computational fluid dynamics model using Eulerian-Lagrangian approach. The developed numerical model is subsequently used to analyze the gas plume in a full-scale scenario. The developed model would help to support risk assessment and response planning of potential subsea gas release accidents.

Adaptability of Turbulence Models for Pantograph Aerodynamic Noise Simulation

This study was targeted at CX‐PG‐type Faiveley pantograph of high‐speed train and cylinders and analysed the fluctuating flow field around these objects by using the large eddy simulation (LES) model, the scale adaptive simulation (SAS) model, the improved delayed detached eddy simulation with shear‐stress transport‐kω (IDDES sst‐kω) model, the delayed detached eddy simulation with shear‐stress transport‐kω (DDES sst‐kω) model, and the delayed detached eddy simulation with realizable‐kε (DDES R‐kε) model. The space distributions of velocity, vorticity, and vortex structures were compared to investigate their performances on simulating fluctuating flow fields and computing aeroacoustic sources through Fourier transformation based on the surface fluctuating pressures. Furthermore, the far‐field radiated noise was calculated based on the Ffowcs Williams–Hawkings equation. Based on the computation precision of the five models, a feasible turbulent model was selected for simulating aerodynamic noise. The relative errors to the results from wind‐tunnel experiments of the sound pressure level (SPL) were obtained as 0.7%, 1.6%, 7.8%, 3.8%, and 12.1%, respectively, and the peak Strouhal numbers were obtained as 2.0%, 8.5%, 5.5%, 11.5%, and 51.0% for cylinder simulation. Moreover, the relative errors of SAS, IDDES sst‐kω, DDES sst‐kω, and DDES R‐kε models to the result from LES of SPL were respectively obtained as 2.3%, 4.5%, 5.6%, and 10.8% for pantograph. Thus, it is conclusive that none of the aforementioned models are comparable with the LES model with respect to the precision in the aeroacoustic simulation. However, SAS, IDDES sst‐kω, and DDES sst‐kω are practically competent with the LES model considering the numerical simulations with respect to the engineering computation precision. The numerical computation model was verified using the wind‐tunnel test results.

A New Neural Mass Model Driven Method and Its Application in Early Epileptic Seizure Detection.

Despite numerous neural computational models proposed to explain physiological and pathological mechanisms of brain activity, a large gap remains between theory and application of the models. Building on the successful application of data-driven methods in epileptic seizure detection, we aim to build a bridge between data and models in this paper. We first propose a novel model-driven seizure detection method based on dynamic features in epileptic EEGs, where the rationale for dynamic features in epileptic EEGs can be clarified in theory by characterizing the variation of parameters of the model. Then we apply the proposed D&F-model-driven method to the problem of early epileptic seizure detection, where the evolution of model parameters selected and optimized by the proposed method is measured and used to detect the starting point of the seizure. Numerical results on two open EEG databases demonstrate that our proposed method does a good job of early epileptic seizure detection. The average detection sensitivity, false positive rate and early detection period attain 100%, 0.1/h, and 7.1s respectively. This paper provides a strategy to characterize EEG signals using a NMM-related method and the model parameters optimized by real EEG may then serve as features in their own right for early seizure detection. An useful attempt to early detect epileptic seizures by combining the neural mass model with data analysis.