Different Combinations Of Parameters Research Articles

But Why Doesn’t It Get Better? Kinetic Plots for Liquid Chromatography, Part I: Basic Concepts

Choosing a liquid chromatography (LC) column for a particular application can be a surprisingly challenging task. On the one hand, column manufacturers give us many options to choose from, including particle types, pore sizes, particle sizes, and different lengths and diameters. On the other hand, we usually do not have time to experimentally evaluate many combinations of these parameters, and sometimes we end up picking something similar to the columns that are already in the drawer. The “kinetic plot” is a powerful graphical tool that can help leverage the best available theory to help us understand how different combinations of parameters (such as particle size and length) will perform in relation to the time needed to get to a particular column efficiency (and thus resolution), and therefore make well-informed decisions when choosing columns.

Solving the Problem of Time, Cost, and Quality Trade‐Off in Project Scheduling under Fuzzy Conditions Using Meta‐Heuristic Algorithms

Balancing the project’s time, cost, and quality involves deciding on different implementation methods for each project activity. Time and cost are minimized simultaneously, and the quality of the final product or service is maximized. Indeed, the use of search methods to determine the optimal execution methods of each activity requires the evaluation and review of various performance criteria such as time, cost, and especially the final quality of each activity. These performance measures, especially the quality of the different implementation methods, are reported and recorded in inaccurate, ambiguous, and vague numbers or concepts. In this research, new methods have been proposed to evaluate and investigate the trade‐off of time, cost, and quality of the project in conditions of uncertainty. This means that by fuzzy number theory, the specifications and conditions of a project are included in the problem of balancing time, cost, and quality. In fact, time, cost, and quality are considered triangular and trapezoidal fuzzy numbers. Also, the fuzzy multiattribute utility function approach (in which the concept of fuzzy computational operators is included) has been used to evaluate different combinations of execution methods of project activities. Since different quality combinations can be obtained with different combinations of parameters involved in the implementation of an algorithm, the Taguchi experimental design method has been used to adjust the parameters of the proposed algorithm. To solve the proposed model, particle mass optimization algorithms and artificial bee colonies have also been studied.

Design of a gas-system for testing the phosphine protection of canisters in respirators

The canister is a critical component of non-powered air-purifying respirators that protects operators from fumigation environments but which typically lacks equipment for the detection of harmful agents. Based on research of the common fumigant phosphine, a device is herein designed to test the phosphine filtering ability of different canisters, and methods of device operation are discussed. The experimental device comprises systems for phosphine input control, canister protection test, phosphine tail gas disposal, and nitrogen purging. Adjustable system pressure and gas flow rate allow testing of a series of parameters under phosphine environments. The device is used to continuously test the protection times of different canisters against different concentrations of phosphine at different temperature and humidity conditions. Three sets of experiments were performed to investigate the testing capabilities of the proposed device and to characterize the protective capacity of canisters at different ambient conditions. The testing threshold of the device, protection times for canisters, and influences of moisture were studied to verify device reliability. Results indicate that the device can effectively test different combinations of parameters and distinguish between different canister performances in a selected threshold range (phosphine concentration ≤5000 ppm and flow rate ≤30 L min−1). Humidity is found to negligibly impact the protection ability of canisters against phosphine.

Optimization of injection parameters from the aspect of dimension accuracy

During the injection molding process, the polymers are subject to shrinkage and bending, which causes an unwanted change in geometry. These deficiencies can be caused by many factors: injection pressure, overpressure, overpressure time, cooling, etc. Within this work, the influence of overpressure and overpressure time on the accuracy of product dimensions is presented. Dimension control was performed by measuring on a 3D coordinate machine. The products are injected in 2 different combinations of parameters. For each combination of parameters, measurements were performed in five injection cycles.

An integrative model of cancer cell differentiation with immunotherapy * *This work is dedicated to the memory of our colleague, director, and great friend Prof. Dr Alejandro José Fendrik (1953–2021).

In order to improve cancer treatments, cancer cell differentiation and immunotherapy are the subjects of several studies in different branches of interdisciplinary sciences. In this work, we develop a new population model that integrates other complementary ones, thus emphasizing the relationship between cancer cells at different differentiation stages and the main immune system cells. For this new system, specific ranges were found where transdifferentiation of differentiated cancer cells can occur. In addition, a specific therapy against cancer stem cells was analysed by simulating cytotoxic cell vaccines. In reference to the latter, the different combinations of parameters that optimize it were studied.

Optimization on Thermomechanical Behavior for Improving the Reliability of Press Pack IGBT Using Response Surface Method

A press pack insulated gate bipolar transistor (PP IGBT) device consists of multiple materials. Under the influence of alternating current and clamping force, the device suffers from complex thermomechanical stress. However, the experience-based packaging design does not consider the coupling effect of junction temperature fluctuation ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Delta T_{\mathrm{ j}}$ </tex-math></inline-formula> ) and mechanical stress, which may not ensure the optimal thermomechanical behavior and cause the advance failure of the PP IGBT device. Thus, it is significant to provide a theoretical basis and select appropriate parameters for device packaging design. In this article, a finite-element model of a 3300-V/50-A PP IGBT device is first built and verified via experiments. The influence of principal parameters on the thermomechanical behavior is then illustrated. Next, the response surface method is proposed to reveal the significance level of each parameter. According to simulation results under different combinations of parameters, quadratic response surfaces are obtained. The combined effects of packaging parameters on <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Delta T_{\mathrm{ j}}$ </tex-math></inline-formula> and stress are clarified. Finally, optimal results are derived and verified. An approximate 4 °C decrease in <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Delta T_{\mathrm{ j}}$ </tex-math></inline-formula> and a 19.8% decrease in stress are achieved simultaneously in the long-time power cycling test. A 2.6 °C reduction in junction temperature is achieved under the practical high-voltage direct current (HVDC) condition.

Выбор и расчет тяговых элементов механизма подъема лифта

The correct choice of elements of the elevator lifting mechanism and their parameters ensures its reliability, durability, energy and economic efficiency. The paper contains recommendations for the selection of the traction elements of the elevator lifting mechanism and the sequence of determining their parameters based on a multivariate calculation. The purpose of the proposed sequence is to obtain the most rational parameters of the traction elements of the elevator lifting mechanism. The initial data for the calculation are the lifting capacity of the elevator, the nominal speed of movement, the height of the lift of the car. It is also necessary to consider the purpose of the elevator. At the first stage of the calculation, the masses of the cab and the counterweight are determined. In this case, the existing data on analogue lifts should be used. In the absence of such data, the approximate dependences proposed by the authors of the article can be used. At the second stage, the kinematic scheme of the elevator is selected. At the third stage, the type of traction element is selected. On the basis of domestic and foreign experience in elevator engineering and well-known literature, recommendations are formulated for choosing the type of traction element. The final stage is a multivariate calculation of traction elements. It is proposed to evaluate the calculation results taking into account the minimum value of the safety factor in accordance with the EN 81-1: 1998 standard. The calculation of the traction elements considered in the work is only a small part of the process of determining the optimal parameters of the elements of the elevator lifting mechanism. At the same time, already at this stage, variability is introduced, which makes the calculation quite laborious to perform it manually. Obviously, a multivariate calculation method that allows you to analyze many different combinations of parameters of the elements of the elevator lifting mechanism and choose the optimal ones is impossible without the use of a computer.

Ateş Böceği Algoritması Kullanılarak Toplu Taşıma Frekans Optimizasyonu ve Parametrelerinin Değerlendirilmesi

ABSTRACT: Over the last few decades, rapidly growing cities in terms of population and land use have led to many transportation-based problems such as longer travel times, traffic congestion, traffic crashes, and air and noise pollution. Increasing the modal share of transit systems appears to be one of the most effective methods to solve transportation-based problems. However, transit systems, particularly in countries having limited resources, should be used efficiently to achieve sustainable urban mobility. Even only adjusting frequencies of transit lines, with no infrastructure investment cost requirements, can provide a more efficient transit system. In this paper, a transit frequency setting model based on the Firefly Algorithm (FA), which is a relatively new metaheuristic, for the transportation network design problems is presented to minimize total user cost under a fleet size constraint. The proposed model is performed on a 10-route Mandl’s Test Network using different combinations of parameters to demonstrate the effect of parameter values on the solution quality. After that, the best solution of 30 solutions obtained by the calibrated parameter values is compared to the existing frequency set of the 10-route transit network. The results show that the FA can obtain better frequency sets by selecting the proper values for the parameters.

Fetal Ilium as a Tool For Sex Determination: Discriminant Functional Analysis

Background: Sex determination has been the most intriguing puzzle for forensic pathologists andanthropologists for which efforts are being done since long. Sexual dimorphism is well established in theadult pelvis and it is known to provide the highest level of information about sexual dimorphism. This studywas conducted to know whether this dimorphism exists in fetal bones?Method: A total of 34 pairs of fetal pelvis bones (22 Males + 12 Females), age ranging from 4 months tofull term were collected from unidentified dead fetuses brought in the Department of Forensic Medicinefor the routine medicolegal autopsies, to study for sexual dimorphism in the Department of Anatomy, Pt.B. D. Sharma PGIMS, Rohtak. Samples were divided in 2 age groups and various metric parameters wererecorded with the help of digital vernier caliper. Data obtained was subjected to descriptive &amp; discriminantfunctional analysis.Conclusion: Results of Descriptive and Discriminant Functional Analysis showed that sex determinationcan be done with 100% of accuracy by using different combinations of parameters of fetal ilium. Thisstudy illustrates that sexual dimorphism exists from early fetal life &amp; after mid pregnancy; it can be clearlyestablished by discriminant functional analysis.This research was limited in its analysis due to less availability of specimens as this represents only theresults in north Indian population. Future studies should be done to explore different populations to betterunderstand the sexual dimorphism in fetal bones of different geographic contexts.

Optimal design of container heat dissipation safety based on five-block method and radial basis function

The ability of the ocean to provide a good thermal environment and not take up land space resources has led to subsea data centres due to their energy efficiency, low failure rates and green sustainability. As a result, there is a growing need for subsea data centres to be structurally sound. This paper investigates the optimal design of data centre capacity and cooling structures to improve their thermal safety performance to a certain extent.Firstly, the temperature quantification of the heat dissipation and heat generation processes is carried out using Newton’s cooling theorem and Fourier’s law of thermal conductivity to provide maximum and minimum constraints for optimization. Then, the " five-block method" is used to optimize the arrangement of internal servers with temperature constraints, considering the problem of packing same-sized items in closed spaces. Based on the quantification of the solid-liquid and solid-solid heat transfer processes and the local temperature analysis as well as the optimization of the boxing, the model yields a maximum of 384 servers for the data center.Secondly, the fin structure is then further optimized for heat dissipation. An approximate model of the fin structure and thermal performance is developed and solved by a radial basis function (RBF) neural network algorithm. Then, based on 100 sets of parameters for the serrated fin structure, the RBF approximation model is used to optimize the range of values for height, pitch and thickness. Based on the three ranges of parameters, Monte Carlo simulations are used to generate different combinations of parameters for different shapes, and to obtain the exact parameter that will increase the surface area by 13.8%. In the case of the first task, a solution is obtained to store 396 servers.

Unveiling an Automated Modeling Method for S0 Galaxies

Abstract The objective of this study is to unveil an optimum and precise automated method to model S0 galaxies. Preliminary results of the study confirm that GALFIT—a two-dimensional image decomposition program—with a Sérsic profile can be used to model S0 galaxies. Since the input parameters affect the accuracy of the model, different combinations of parameters were tested to obtain the best-fit model. An automated GALFIT fitting process was developed using Python and Astropy module to increase the efficiency of the process. A sample of S0 galaxy images observed at the Kitt Peak National Observatory was used to test the precision of the implemented method. The accuracy of the created models was tested both visually and statistically. The new method will allow us to model a large sample of S0 galaxies accurately and determine their structure and properties.

Truck Scheduling for Cross-Docking of Fresh Produce with Repeated Loading

Due to mismanagement of supply chain operations, fresh produce, which deteriorates highly depending on time and operating environment (including temperature and humidity), will suffer huge losses in transit, resulting in substantial monetary losses. Cross-docking, as an efficient logistics operation strategy, has been widely used in fresh produce distribution in the cold supply chain, whereas it has not received adequate attention in the scientific literature. In order to improve the efficiency of fresh produce distribution, this study formulates a novel mixed-integer mathematical formulation model that allows repeated loading of outbound trucks to minimize the total deterioration (TD) of all the fresh produce in the cross-docking center. To solve this problem, an advanced genetic algorithm is proposed based on a constructional mixed chromosome with two parts and three levels. The numerical analyses are conducted on 10 typical instances under different combinations of parameters. Results show that our proposed model based on the repeated loading mode can effectively decrease the total deterioration compared with the traditional nonrepeated loading mode. And this superiority becomes more significant, as the value of truck changeover time and lot loading quantity (called lot size in the text) decrease. In particular, when the truck changeover time equals 0, the total deterioration obtained under repeated loading mode will be more than 31.8% on average smaller than that under nonrepeated loading mode.

Analyzing the Effect of Hyper-Parameters on a Neural Network for Emotion Detection

Human emotion prediction is a tough task. The human face is extremely complex to understand. To build an optimal solution for human emotion prediction model, setting hyper-parameter plays a major role. It is a difficult task to train a neural network. The poor performance of the model can result from poor judgment of sub-optimal hyper- parameters before training the model. This study aims to compare different hyper-parameters and their effect to train the convolutional neural network for emotion detection. We used different methods based on values of validation accuracy and validation loss. The study reveals that SELU activation function performs better in terms of validation accuracy. Swish activation function maintains a good balance between validation accuracy and validation loss. As different combinations of parameters behave differently likewise in optimizers, RMS prop gives less validation loss with Swish whereas Adam performs better with ReLU and ELU activation function.

Assessment of probabilistic models to estimate the occupancy state in office buildings using indoor parameters and user-related variables

Occupancy modeling in office buildings is still in progress and needs to be developed by using observable data. In this paper, an office building under the Mediterranean climate was instrumental in the collection of both indoor environmental parameters (air temperature and relative humidity, CO2, VOC) and user action-related variables (electricity power, window, door state, and air conditioning use). Each parameter was monitored along with the occupancy state at a one-minute time step for two years. The purpose of the investigation was to evaluate the potential application of three straightforward models, such as the Law of Total Probability (LTP), Naïve Bayes classifier (NB), and Classification and Regression Tree (CART), to estimate the occupancy state using the indoor measurements. Thirty-four (34) different combinations of parameters were applied on the developed models; the true positive rate (TPR), true negative rate (TNR), and accuracy were used as evaluation metrics. The results confirmed that the performances of the models were influenced by both the number and the typology of the used parameters. In particular, the CART model was found to be the least affected by them; almost half of the parameters’ combinations provided accuracies higher than 93% and TNR higher than TPR. Accuracies of the order of 90% were obtained with NB and LTP.

Delamination and hole wall roughness evaluation in air-cooled drilling of carbon fiber-reinforced polymer

Drilling of carbon fiber-reinforced polymer (CFRP) is widely employed in manufacturing processes in the aeronautical, automobile, and energy industries. The evaluation of the hole region focusing on wall roughness and delamination phenomena is extremely important to predict bolted joints' performance, where at least one of the adherent is a composite material. Thus, this work performed a statistical analysis on the delamination (entrance and exit of the plate) and wall roughness of drilling holes in an 8.6 mm thick CFRP plate carried out by an uncoated carbide drill under compressed air-cooling, varying the cutting speeds and feed rates. Since air-cooling usage combines positive aspects, such as low-cost implementation and shorter process time compared to ultrasonic-assisted drilling, it turns out to be an excellent alternative for aeronautical industry. Thus, the main contribution of the present work consists on analyzing the variation of the delamination in the entrance and exit of the first and tenth holes of a CFRP plate after dry and air-cooled drilling. This variation of the delamination between the cold drill (first hole) and the heated drill due to the drilling holes' sequence (after ten holes) is investigated for 18 different combinations of parameters (runs). For instance, it is shown that if the combination of parameters values is suitable, then it is possible to reduce the mean value of adjusted delamination factor for the entrance of the tenth hole around 11% when comparing cooled-air with dry cutting.

Компьютерное моделирование прессового соединения

The design of modern technology is associated with increased requirements for strength and manufacturability. Press fit connections of small size parts can withstand significant workloads, so they are widely used in mechanisms and machines. Traditionally, the calculation of press fit connections is performed according to classical formulas using a large amount of reference data. The calculations use standard recommendations that make it easier to obtain solutions with a minimum investment of time. However, the time saving limits the search to a few joints, which are not always the best in some indicators. Modeling press fit joints with different combinations of parameters leads to the formation of hundreds of potential joints. To check their performance, it is necessary to use modern computing facilities. The computer has almost unlimited possibilities for computing speed and storing arrays of information. Simulation of press fit connections on a computer allows obtaining regression metamodels, accessing the statistical significance of parameters, and determining the area of workable connections. It becomes possible to optimize the design of the joint in terms of strength, weight and assembly technology. The system for calculating and statistical analysis of press fit connections has been developed on the basis of existing standards. A program has been developed providing the joints formation and verification with an assessment of their suitability for the specified requirements.

Robust Coarse-to-Fine Registration Scheme for Mobile Laser Scanner Point Clouds Using Multiscale Eigenvalue Statistic-Based Descriptor

To overcome the drawbacks of pairwise registration for mobile laser scanner (MLS) point clouds, such as difficulty in searching the corresponding points and inaccuracy registration matrix, a robust coarse-to-fine registration method is proposed to align different frames of MLS point clouds into a common coordinate system. The method identifies the correct corresponding point pairs from the source and target point clouds, and then calculates the transform matrix. First, the performance of a multiscale eigenvalue statistic-based descriptor with different combinations of parameters is evaluated to identify the optimal combination. Second, based on the geometric distribution of points in the neighborhood of the keypoint, a weighted covariance matrix is constructed, by which the multiscale eigenvalues are calculated as the feature description language. Third, the corresponding points between the source and target point clouds are estimated in the feature space, and the incorrect ones are eliminated via a geometric consistency constraint. Finally, the estimated corresponding point pairs are used for coarse registration. The value of coarse registration is regarded as the initial value for the iterative closest point algorithm. Subsequently, the final fine registration result is obtained. The results of the registration experiments with Autonomous Systems Lab (ASL) Datasets show that the proposed method can accurately align MLS point clouds in different frames and outperform the comparative methods.

Immediate analgesic effect of transcutaneous electrical nerve stimulation (TENS) and interferential current (IFC) on chronic low back pain: Randomised placebo-controlled trial

ObjectiveTo compare the immediate analgesic effect of transcutaneous nerve stimulation (TENS) and interferential current (IFC), with different combinations of parameters, in individuals with chronic low back pain (CLBP). Methodology280 individuals with CLBP were included in the study, both genders, randomized in 8 groups: GI2KHz/100Hz, GI2KHz/2Hz, GI4KHz/100Hz, GI4KHz/2Hz, placebo interferential group (GIP), GT100Hz, GT2Hz, and placebo TENS group (GTP). All individuals underwent a single application of TENS or IFC for 30min. The assessments were carried out prior to the intervention, as well as immediately after, with the following outcomes: pain intensity (Numeric Pain Rating Scale-NPRS), qualitative pain characteristics (McGill Pain Questionnaire-MPQ), and pressure pain threshold (PPT) by pressure algometry (PA) in 4 points of the low back region. ResultsIn the intergroup comparison of NPRS, all intervention groups showed greater pain reduction compared to GTP (p < 0.05). In the total MPQ score, the groups that obtained significant results (p < 0.05) when compared to GTP were GT100Hz and GT2Hz, while the groups GT100Hz and GI4KHz/100Hz were significant when compared to GIP. In the PA, GI4KHz/100Hz showed an increase in the PPT in all points compared to GTP and GI2KHz/100Hz. ConclusionBoth TENS and IFC presented immediate analgesic effect in CLBP, with emphasis on the interferential current of 4 KHz modulated at 100Hz.

Formulation and Characterization of a Kinetically Stable Topical Nanoemulsion Containing the Whitening Agent Kojic Acid

The research was carried out to synthesize a stable kojic acid (KA) encapsulated nanoemulsion as a whitening agent for topical skin usage. In this study, the oil-in-water (O/W) KA nanoemulsion was formulated using integrated low and high energy methods that combined ultrasonic and hot temperature inversion methods. Several different combinations of parameters were screened, viz. xanthan gum amount (1.0 to 2.0 g), kojic acid (KA) amount (0.5 to 1.5 g), and surfactant-to-water ratio (1:10.75 to 1:4.875), to prepare a stable KA nanoemulsion. The identified best parameters to design the O/W KA nanoemulsion were then subjected to different stability tests: storage and pH stability (freeze-thaw and centrifugal tests). Results revealed that the Trial 6 formulation, with the highest ratio of Tween 80 to water (1:4.875 v/v), yielded the best polydispersity index at 0.255 ± 0.006 with an average particle size of 90.57 ± 1.401 nm. The formulation retained the recommended pH range (pH 4.95–5.18) for topical skin applications within six-week storage under room condition. The nanoemulsions were also kinetically stable as proven by the absence of phase separation after the centrifugation, freeze-thaw cycle, and storage temperature (2 and 25 °C) tests, except at the 37 °C three-week extended storage. The results collectively showed that the formulated O/W KA nanoemulsion is suitable for topical application on human skin.

A semi-empirical model for water inflow into a tunnel in fractured-rock aquifers considering non-Darcian flow

Water inflow into a tunnel is usually estimated by assuming that the flow follows the linear Darcy’s law. However, fluid flow in fractured-rock aquifers is prone to deviation from Darcy’s law and gives rise to nonlinear flow phenomena due to significant inertial losses. This non-Darcian effect is seldom considered when evaluating water inflow into the tunnel in a fractured-rock aquifer. In this study, we investigated an analytical method for predicting water inflow into a tunnel considering the non-Darcian effect. A series of numerical simulations for water inflow into a tunnel were conducted with different combinations of parameters, where non-Darcian flow was considered and characterized by the Forchheimer’s law. Based on the numerical results and an ingenious parameter integration method, a semi-empirical model was developed to analytically predict water inflow into a tunnel where the flow is under non-Darcian flow regime. The semi-empirical model includes the classic theoretical formula for predicting water inflow and the Forchheimer equation for describing non-Darcian flow. In this context, the non-Darcian effect on water inflow into a tunnel can be quantitatively estimated. This developed model has a concise expression satisfying dimensional consistency with the parameters having sound physical meanings, and it can be successfully reduced to the classic formula under the Darcy flow regime. The validity of this semi-empirical model was confirmed by numerical results, showing a high fidelity in predicting water inflow into a tunnel. By means of this proposed model, the error induced by neglecting non-Darcian effect was estimated for a large number of real engineering cases, which rapidly increased as a power function with the magnitude of water inflow into the tunnel. The necessity of considering the non-Darcian effect when calculating water inflow was thus proven, especially for massive tunnel gushing. The proposed model and the method used in this study can provide guidance for accurately predicting water inflow into a tunnel under a complex non-Darcian flow regime.