Determination Of Coefficients Research Articles

PENGARUH CITRA DESTINASI DAN E-WOM TERHADAP KEPUTUSAN BERKUNJUNG WISATAWAN NUSANTARA KE PULAU LIHAGA, SULAWESI UTARA


 
 
 The background of this research is to find out the influence of destination image and E- WOM on Domestic Tourist Visit Decision to Lihaga Island, North Sulawesi. Determination of the sample in this study used a purposive sampling method with a total sample of 100 respondents. The data collection used the distribution of questionnaires online through social media, observation, literature study, and documentation. The techniques used in this research are descriptive quantitative with validity test, reliability test, classical assumption test, multiple linear regression analysis, t-test, f- test, and coefficient of determination test. For the tool used for the implementation of this data analysis test is IBM SPSS statistics 25. The results of this study indicate that destination image does not significantly influence the visit decision, while E-WOM has a significant effect on visit decision. The results of this study are destination image and E-WOM done simultaneously has an influence on domestic tourist visit decisions. The results of coefficient determination (Rsquare) is 60%.
 
 

Study of the influence of the structure of rolled iron on its hardness

Problem. The influence of the structure of cast irons on their hardness was studied using multifractal analysis. The spectrum of statistical dimensions of the cast iron microstructure was calculated using the Renyi formula. Materials and methods. The hardness of chromium-nickel cast iron was determined at three points of the sample. Results of experiments. It was found that the pairwise correlation coefficients for predicting hardness by traditional structure characteristics (length, diameter, area) were R2 = 0.73...0.87. When assessing hardness indicators by multifractal characteristics, the correlation coefficients are 0.78...0.88 for the pearlite structure with flake graphite and 0.81...0.93 for the pearlite structure with spherical graphite. The sensitivity coefficients of the hardness indicators of СПХН-43 rolls to the information and correlation dimensions of carbides, as well as to the fractal and statistical D-100 dimensions of flake graphite were determined. The sensitivity of hardness indicators to the fractal and statistical D100 dimensions of carbides and to the fractal and correlation dimensions of flake graphite was determined for СПХНФ-47 rolls. Conclusions. Based on the results obtained, an approach to assessing the hardness of СПХН-43 and СПХНФ-47 rolls was developed, which includes: 1). Determination of the statistical dimension spectrum of the cast iron structure elements. 2). Determination of the sensitivity coefficients of hardness indicators to the spectrum of dimensions of structural elements. 3). Creation of a mathematical model for predicting the hardness of rolls. The considered approach can be interpreted as an alternative method for assessing the quality criteria of cast irons based on the analysis of their structure.

Analysis of e-WOM and Destination Image on Visit Intention

The global spread of the Coronavirus impacts the Indonesian economy, particularly in the tourism industry, Various kinds of tourist attractions in Indonesia are threatened with closing due to the COVID-19 pandemic, and various sectors - supporting tourism sectors such as hotels, restaurants, and retail entrepreneurs are also affected by this coronavirus. Alamendah Tourism Village is one of the tourist attractions affected by the Covid-19 pandemic. This research aims to analyze the impact of e-WOM and destination image on visit intention for the Alamendah Tourism Village, this research uses quantitative method and descriptive causality research. This research was conducted on 100 respondents who had never visited Alamendah Tourism Village. Data was collected by distributing questionnaires, and the data were processed using SPSS 21. The t-test f-test and coefficient determination are used to test hypotheses. It was discovered that the e-WOM had a significant and strong impact on visiting interest and that the destination image also had a significant and strong impact on visit intention. Furthermore, the e-WOM and destination image have a significant and strong impact of 45,9% on visit intention simultaneously, with the rest being influenced by other variables.

Thermo-elasticity of multi walled carbon nanotube- natural rubber/acrylonitrile butadiene rubber blends

Natural rubber nano-composites are emerging as one of the key players in the industry and research due to its novel material properties and nano functionalities. In order to create high performance natural rubber nano-composites, new multifunctional nano-fillers can be created using a various approaches due to the advances of nanotechnology. Blends of natural rubber (NR) and acrylonitrile butadiene rubber (NBR) were used to evaluate the effects of various constitutional ratios between the two substances of fixed weight of multi walled carbon nanotubes (MWCNTs). The increase in the frequency of alternating extension (fatigue deformation) for samples (B2, B3) causes an increase in the thermo-elastic temperature change. The breakdown of the structure is thought to be prevailing at high strain amplitude and consequently may account for the observed effect. The thermo-elastic measurements also involve the determination of the thermo-elastic coefficient, change in entropy, internal energy per unit length, and Gruneisen constant. All these parameters were found to be highly dependent on both fatigue parameters and NR/NBR polymer ratios in the composite. The prepared sample (50/50 phr) can be used as thermo-elastic sensors.

ASSESSING THE EFFICACY OF CLOUD SERVICES FOR DEVELOPING EDUCATIONAL PRESENTATIONS

The article examines the most popular cloud services for creating educational presentations and seeks to determine the effectiveness of their integration within the educational framework. A webometric analysis of these cloud services resulted in the identification of the top 10 resources commonly employed for presentation creation, including Prezi, Sway, Slides, PowToon, Canva, ZohoShow, Genial.ly, Emaze, Piktochart, VideoScribe, among others. Our research conducted a comprehensive comparative analysis of these platforms, utilizing web analytics tools such as Ahrefs, Moz, and Similarweb to establish their respective rankings. This approach facilitated an encompassing selection of cloud-based educational tools capable of meeting the multifaceted requirements of all stakeholders in the educational process. The analytical process unfolded across multiple stages: an initial description and assessment of key parameters of each cloud service, subsequent expert evaluations encompassing both parameter specifics and overall service quality, determination of individual parameter impact coefficients on service efficiency, service evaluations based on specific parameters, and a synthesis of both objective and subjective data to summarize outcomes. In-depth analysis was conducted on the presentation creation features inherent to each cloud service, leading to the identification of evaluation parameters encompassing functionality, usability, cost-effectiveness, unique attributes, and overall user impression. Each parameter was assigned an impact factor to gauge its significance within the overall assessment of a given cloud service. The culmination of expert evaluations culminated in the recognition of Prezi, Canva, and Google Slides as highly effective tools. This determination is grounded in their extensive functionality, provision of free accounts, and user-friendly interfaces. Analysis of domain ratings further highlighted the popularity of Sway, Canva, and Prezi, underscoring the pronounced demand for these platforms among users. The evaluation methodology proposed within this study holds potential for application to other cloud services designed for educational content creation. By fostering effective organization of educational activities across diverse subject domains, this approach contributes to the enhancement of the educational process as a whole.

The Influence of Working Capital Turnover and Debt to Equity Ratio on Return on Asset

The Covid-19 pandemic in 2020 caused the performance of the pharmaceutical subsector to fluctuate. From these results, it can be seen that the Return on Assets of pharmaceutical subsector companies has decreased and Working Capital Turnover has also decreased. The low working capital turnover was due to a decrease in current assets and an increase in current debt used to finance company projects. A low working capital turnover ratio means that working capital processing is not running well, whereas a high working capital turnover ratio means that the company's working capital is functioning effectively. This research aims to know the influence of Working Capital Turnover and debt-debt-equity ratio on Return on Assets in companies' subsector pharmacy period 2017-2022. Data analysis techniques used that is analysis Descriptive and Verifiable using the Assumption Test Classic, Multiple Linear Regression Test, Analysis Coefficient Correlation, Analysis Coefficient Determination, and Hypothesis Testing. The results of this research show that the Working Capital Turnover Variable has partially no influence on the Return on Assets and the Debt to Equity Ratio variable has Partial influential negatively on the Return on Assets Overall Simultaneous Working Capital Turnover and Debt to Equity Ratio affect the Return on Assets.

Development of oil extraction screening methodology taking into account innovative methods using the example of the Ukrainian field

The object of research in the paper is the process of fluid transfer through the pore space of the reservoir rock. The traditional method of estimating oil recovery by flooding has a large number of uncertainties. In this study, to address limitations of the current approach to determining oil production, let’s introduce a systematic algorithm aimed at enhancing result precision. The methodology for calculating the oil recovery coefficient for determining the amount of oil that can be extracted by flooding is presented. In this work, the step-by-step process of determining the oil recovery coefficient was analytically established, which achieves a certain degree of accuracy due to the inclusion of a number of methods of calculation of scientists from different countries of the world. In particular, the lithofacies distribution of the reservoir using the kriging method, the use of a representative elementary volume (REV) to increase the accuracy of determining the irreducible water saturation of each facies, and the use of the Buckley-Leverett equation in the calculation of the oil recovery coefficient are proposed. The number of facies (sandstone, argillaceous sandstone, siltstone) was determined on the example of the B-16n horizon of the «Ukrainian deposit» and the oil recovery coefficients were calculated for each separately (0.53, 0.47, 0.29). Further determination of the average oil recovery coefficient is described in the researched and requires close integration of the obtained data in three-dimensional space, as it allows to calculate the fraction of facies content in the reservoir volume. The use of the proposed action algorithm will help to build a more reliable three-dimensional hydrodynamic model, will lead to a much lower degree of uncertainty of reservoir properties, and in particular irreducible water saturation, as well as more accurate distribution of lithological properties using kriging. Also, this methodology for calculating the oil recovery coefficient involves the use of the Buckley-Leverett equation and fractional flow curves, the data of which are based on relative permeabilities and depend on the irreducible water saturation determined in the laboratory for each lithofacies. These techniques justify the collection of additional core material, the importance of lithofacies dismemberment of the formation and are closely integrated in the three-dimensional space, which makes it possible to simulate the existing processes, reproduce the proposed methodology and perform the forecast.

Electrodeposited Lithiophilic Zn Thin Film on the Current Collector for Improved Cyclability of Anode-Free Lithium Metal Battery

Anode-free lithium metal batteries (AFMBs) are recently presented as the new generation of Li metal batteries benefiting high gravimetric and volumetric energy densities due to the zero excess lithium. However, poor electrochemical stability and maximum cyclability of around 40-50 cycles due to the zero excess Lithium prevent the AFLMBs to be functional1. Here, lithiophilic electrodeposited Zn thin film on the current collector is reported in order to decrease the lithium nucleation overpotential and improve the plating/stripping process during alloying and dealloying. Moreover, columbic efficiency is increased by applying more zinc coated on the cupper current collector and by providing a more hospitable site for Li nuclei to plate2. Due to the alloy formation of Li-Zn, more conformal Li growth on the current collector is provided and homogeneous Li distribution and smooth morphology are observed by SEM images. The cells in different zinc thin layer coating are cycled with different current densities as well as long-term cycling by galvanostatic cycling charge-discharge cycling. As a result, increasing the thin film thickness up to 1 micron significantly enhances the electrochemical stability of the cells such as higher columbic efficiency and cyclability, lower Li nucleation overpotential. Finally, the Li-ion chemical diffusion coefficients DLi, are evaluated by galvanostatic intermittent titration technique (GITT) and electrochemical impedance spectroscopy (EIS) and the results are compared to each other3.References Maddukuri, S. et al. On the challenge of large energy storage by electrochemical devices. Electrochim Acta 354, 136771 (2020).Merso, S. K. et al. An in-situ formed bifunctional layer for suppressing Li dendrite growth and stabilizing the solid electrolyte interphase layer of anode free lithium metal batteries. J Energy Storage 56, 105955 (2022).Xie, J. et al. Determination of Li-ion diffusion coefficient in amorphous Zn and ZnO thin films prepared by radio frequency magnetron sputtering. Thin Solid Films 519, 3373–3377 (2011).

Investigating the Electro-Osmotic Coefficients of PFSA and Anion-Exchange Ionomers Using Microelectrodes

The electro-osmotic coefficient of ionomer membranes is a significant water management property that quantifies the number of water molecules dragged with the mobile ion (typically a proton) when that ion moves due to the operation of an electrochemical cell or an electric field. This coefficient becomes critical when attempting to model water distribution and movement in fuel cells and electrolyzers, where water is an important factor influencing device performance. However, there is disagreement on the value of the electro-osmotic coefficient for PFSA membranes and little significant study of the coefficient in anion exchange membranes (AEMs). Here we present an electrochemical, two-electrode method of determining the electro-osmotic coefficient of ionomers using differential relative humidity (RH) measurements. This approach allows for more accurate determination of the electro-osmotic coefficient. We present the electro-osmotic coefficient as a function of temperature and mobile ion for a variety of ionomers, including Nafion, sulfonated polystyrene, Versogen,, and Sustainion. In addition, a model based on the Maxwell-Stefan-Onsager framework is developed for the AEMs, enabling calculation of the membrane water permeability via fitting of the electro-osmotic coefficient. These coefficients will allow for more accurate models of water transport in electrochemical systems, leading to a greater understanding of the inefficiencies in these systems and, hopefully, insight into how to improve them. This work was supported by the HydroGEN Advanced Water Splitting Materials consortium, which is supported by the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Hydrogen and Fuel Cell Technologies Office, under contract number DE-AC02-05CH11231.

Phytochemical composition and insecticidal effects of native plant extracts against the mango mealybug, Rastrococcus invadens Williams (Homoptera: Pseudococcidae)

The mango mealybug Rastrococcus invadens Williams causes enormous damage to fruit trees in Burkina Faso, with losses of up to 90% for mango trees and 53% for citrus fruits. The objective of this study was to evaluate the insecticidal effects of native plant extracts against this insect pest. The insecticidal activity and biological effectiveness of the extracts were evaluated on Petri dishes and mango leaves previously contaminated by spraying them with the native plant extracts. The experimental was a completely randomized Fischer block, and compared six doses of the hydroalcoholic extracts of A. conyzoides and H. suaveolens with abamectin 18 EC and water (control). These treatments were repeated up to ten times. The determination of the efficiency coefficients was achieved using Abbott's formula (1925). Both extracts of A. conyzoides and H. suaveolens were effective, but the one based on A. conyzoides at 50 gl -1 was the most effective with 100% mortality in 48 hours compared to 95.00% for H. suaveolens’ extract in 72 h. Their respective LC50 were 12.50 gl -1 and 17.49 gl -1, showing that A. conyzoides’ extract is more toxic to R. invadens. The high content in phenols, flavonoids, alkaloids, etc. of leafy stems of A. conyzoides and of H. suaveolens could help to sustainably control R. invadens in an integrated approach and effectively protect mango orchards.

(Invited) Evaluating Chemical Doping and Charge-Carrier Transport in Carbon Nanotube Dispersions

Chemical charge-transfer, or redox, doping has long been recognized as a powerful approach to tune the charge carrier density in pi-conjugated semiconductors. Despite this, and the extensive effort that has been put into developing novel redox dopants, several challenges remain to understand (i) the doping mechanism/efficiency, (ii) the interactions between the injected charge carrier and the associated counterion, and (iii) the impact that these have on charge carrier transport. This is complicated by the fact that it is very difficult to accurately measure charge carrier densities in pi-conjugated semiconductors and to assess carrier-counterion interactions. Here we employ dispersions of enriched semiconducting single-walled carbon nanotubes (s-SWCNT) as a prototypical pi-conjugated semiconductor, since the rigid structure and strong optical transitions offer some advantages over typically more disordered conjugated polymers. We employ a suite of spectroscopic techniques to probe charge carrier doping and transport in isolated polymer-wrapped s-SWCNT in a low dielectric constant solution-phase environment. We compare solution-phase s-SWCNT samples in toluene that are p-type doped by either 2,3,5,6-tetrafluoro-7,7,8,8-tetracyano-quinodimethane (F4-TCNQ) or (2,3,4,5,6-pentafluoro)benzyloxy-substituted icosahedral dodecaborane cluster (DDB-F60). We use a combined approach of steady state optical spectroscopy with 19F NMR studies. Optical spectroscopy allows us to track the bleach of the electronic transitions due to excitons and the appearance of signature due to charge carrier-induced trions, which we can correlate to the concentration of dopant counterions extracted from NMR experiments. This combined methodology allows for quantitative determination of a molar extinction coefficient for free carriers for the SWCNT dispersion. We subsequently show that DDB-F60 is a more potent charge-carrier dopant than F4-TCNQ at low concentrations but that the ultimate injected hole charge-carrier density is limited by the large size of the DDB-F60 counteranion, due to saturation of the carbon nanotube surface area that is accessible to the dopant molecules. Using a non-contact spectroscopy technique in the microwave frequency region (ca. 9 GHz), we show that the holes injected by DDB-F60 are more delocalized and mobile, consistent with calculations that suggest a smaller coulombic binding energy between the hole on the carbon nanotube and the electron on the DDB-F60 counteranion. However, samples doped by F4-TCNQ reach a higher peak conductance than is achieved by DDB-F60 doping, where the conductance in the latter case is limited by the maximum achievable hole charge-carrier density and hole scattering processes that reduce the carrier mobility at high hole densities. Our observations point to the need to understand the subtle balance between the carrier-counterion interactions and the injected charge-carrier density to optimize charge-carrier transport in chemically doped s-SWCNT systems.

Quality Development of Soft Drinks Based on the Qualimetric Model Engineering

A number of doctrinal documents of the Russian Federation define the need for the non-communicable chronic disease prevention, and as a consequence, the health promotion by including specialized foods in the diet. From the list of homogeneous product groups, beverages are the most convenient for the functional property development, have simple production technology and are in demand with different population groups. All of those things determine the prospects for further development of the alcohol-free beverages. To forecast the quality and consumer characteristics of the projected alcohol-free beverages, a man developed a process for qualimetric model engineering of the expected assortment properties of drinks based on aspen leaves containing substances with pronounced antioxidant properties based on the example of the Yugorsky drink. The relevance of such research consists in the complex development including the maximum quality properties set of the projected product, in the formation of which engineers, consumers and experts participate. The development process of a qualimetric model for the quality engineering of beverages consists of five stages: identification of significant indicators inherent in this product group; "properties tree" developmen alcohol-free beverages; selection or development of scales for the beverage consumer properties assessment, weighting coefficient determination; complex (integral) indicator determination of the beverage quality. The authors emphasize the stages study depth importance of the new product development process and the degree of its detailing, depending on the knowledge and vision of all participants in the process.

CORRECTION OF THE CYLINDRICAL HELICAL-GEAR WHEEL PAIR FOR WEAR DECREASE OF TEETH’ INVOLUTE SURFACES

Purpose. It is to create a method for determination of profile shift coefficients, such that during the operation of a cylindrical helical-gear pair the sum of the wear rates of involute surfaces on the contacting sections at the highest and lowest active points of teeth’ profiles of driving and driven wheels will be a minimum.
 Research methods are based on integrated application of the involute gear theory and tribological laws. The secant method that is known in computational mathematics is used to find a root of nonlinear equation.
 Results. The method is created for determination of rational values of correction parameters for cylindrical helical-gear wheels, which maximize the service life of this gear pair until the maximum sum of worn-layer thicknesses on the contacting sections of the teeth’ active surfaces reaches limiting permissible value. An example of application of this method in design calculation of the cylindrical helical-gear pair is given.
 Scientific novelty. Calculation model is elaborated for determination of the sum of worn-layer thicknesses on the most wearing contacting sections of the teeth’ active surfaces of a cylindrical helical-gear wheel pair. It is derived an equation of the linkage between such values of profile shift coefficients for the driving and driven helical-gear wheels which minimize the greatest sum of wear rates on mentioned sections of teeth’ surfaces. Solution of this equation by numerical method for the helical-gear pair having standard distance between axes allows determination of rational values of correction parameters for these wheels.
 Practical value. Application of the created method for determination of profile shift coefficients is expedient in design of cylindrical helical-gear pairs for machines and equipment, which operate in conditions when it is impossible to protect the engagement region from ingress of abrasive particles.

Magnetic Persimmon Leaf Composite: Preparation and Application in Magnetic Solid-Phase Extraction of Pesticides in Water Samples.

In recent years, the utilization of biomass materials for the removal and detection of water pollutants has garnered considerable attention. This study introduces, for the first time, the preparation of Fe3O4/persimmon leaf magnetic biomass composites. The magnetic composites were employed in a magnetic solid-phase extraction method, coupled with gas chromatography-electron capture detection (GC-ECD), for the analysis of four pesticides (trifluralin, triadimefon, permethrin, and fenvalerate) in environmental water samples. The innovative magnetic persimmon leaf composites were synthesized by in situ generation of Fe3O4 nanoparticles through coprecipitation and loaded onto persimmon leaves. These composites exhibit superparamagnetism with a saturation magnetization of 12.8 emu g-1, facilitating rapid phase separation using a magnetic field and reducing the extraction time to 10 min. Desorption can be achieved within 30 s by aspirating 20 times, eliminating the need for time-consuming and labor-intensive experimental steps like filtration and centrifugation. The specific surface area of the magnetic composite adsorbent increased from 1.3279 m2 g-1 for the original persimmon leaf to 5.4688 m2 g-1. The abundant hydroxyl and carboxyl groups on the composites provide ample adsorption sites, resulting in adsorption capacities ranging from 55.056 mg g-1 to 73.095 mg g-1 for the studied pesticides. The composites exhibited extraction recoveries ranging from 80% to 90% for the studied pesticides. Compared to certain previously reported MSPE methods, this approach achieves equivalent or higher extraction recoveries in a shorter operation time, demonstrating enhanced efficiency and convenience. Good linearity of the target analytes was obtained within the range of 0.75-1500 μg L-1, with a determination of coefficient (R2) greater than 0.999. These findings contribute to the use of magnetic persimmon leaf biomass materials as effective and environmentally friendly adsorbents for pollutant determination in water samples.

Conformational states of NADH in water–alcohol solutions studied by molecular dynamics simulations

Redox reactions in living cells involving a coenzyme nicotinamide-adenine-dinucleotide (NAD) are stereospecific and depend on NAD conformation states and on the structure of enzyme binding sites. Therefore, information on NAD conformation states in various environments is important for understanding of the mechanisms of redox reactions. In this paper the structural dynamics of reduced nicotinamide-adenine-dinucleotide (NADH) in water–methanol and water–ethanol solutions was investigated by means of molecular dynamics simulations. The trajectory analysis revealed three stable conformation groups characterized by the distance RNA−AD between adenine and nicotinamide centers of mass: folded (RNA−AD< 5.5 Å), intermediate (5.5 Å <RNA−AD< 12 Å) and unfolded (RNA−AD> 12 Å). It was shown that conformation equilibrium shifted from the folded conformation group at low alcohol concentrations towards the intermediate conformation group at high alcohol concentrations, while the fractional concentration of unfolded conformation group remained almost constant. The nicotinamide and adenine rings were found to be almost parallel in folded conformations and perpendicular in intermediate conformations, while no preferable positions of the rings were found in unfolded conformations. The results obtained were used for the analysis of experimentally determined rotational diffusion times τrexp in NADH in water–methanol and water–ethanol mixtures. Comparison between the calculated and experimental τr values using the generalized Stokes–Einstein–Debye equation allowed for determination of the wettability coefficient C and effective molecular volume Vm as a function of alcohol concentration. The coefficient C was found to be always less than unity and have a minimum at 40% of alcohol which was more pronounced for ethanol than for methanol mixtures. This dependence was attributed to the influence of solution viscosity that has a maximum at 40% of alcohol. The effective molecular volume Vm was found to be practically constant at alcohol concentrations below 60% and rise dramatically at higher alcohol concentrations. This dependence was attributed to the solvation of NADH at high alcohol concentrations.

Study on the Mechanical Properties of Polyurethane-Cement Mortar Containing Nanosilica: RSM and Machine Learning Approach

Polymer-modified cement mortar has been increasingly used as a runway/road pavement repair material due to its improved bending strength, bonding strength, and wear resistance. The flexural strength of polyurethane–cement mortar (PUCM) is critical in achieving a desirable maintenance effect. This study aims to evaluate and optimize the flexural strength of PUCM involving nano silica (NS) using a central composite design/response surface methodology (CCD/RSM) to design and establish statistical models. The PU binder and NS were utilized as input parameters to evaluate the responses, such as compressive and flexural strength. Moreover, machine learning (ML) algorithms including artificial neural networks (ANN) and Gaussian regression process (GPR) were used. The PUCM mixtures were prepared by adding a PU binder at 0%, 10%, 15%, and 25% by weight of cement. At the same time, NS was incorporated into the mortar mixes at 0 to 3% (interval of 1%) by cement weight. The results showed that the simultaneous effect of PU binder at the optimal content and NS improved the performance of PUCM. Adding NS to the mortar mixture mitigated some of the strength lost due to the PU binder, which remarkably reduces the strength properties at a high content. The optimized PUCM can be obtained by partly adding 3.5% PU binder and 2.93% NS particles by the weight of cement. The performance of the machine learning algorithms was tested using performance indicators such as the determination of coefficient (R2), mean absolute error (MAE), mean-square error (MSE), and root-mean-square error (RMSE). The GPR algorithm outperformed the ANN with higher R2 and lower MAE values in the training and testing phases. The GPR can predict flexural strength with 90% accuracy, while ANN can predict it with 75% accuracy.

Determination of the heat transfer coefficient between pellets and air during the modernization of a pelletizing tower based on industrial research

The object of research is the heat transfer coefficient between pellets and air flow in industrial granulation towers. The problem lies in the difficulty of optimizing the heat transfer process. As a result of experiments and analysis, it was shown that each granulating tower for the production of mineral fertilizers has unique properties that significantly affect the efficiency of heat transfer. There are general mathematical models, but for accurate modeling and optimization of heat transfer, the unique characteristics of each production must be taken into account. The results showed that creating an accurate mathematical model for each specific fertilizer production is a difficult task due to the large number of unmeasured or difficult to reconcile factors. The method of calculating the heat transfer coefficient for the granulator tower obtained in the course of the work derives from a set of researches on the production of mineral fertilizers. This approach is based on the analysis of technical parameters and granulation composition of the product. The developed method makes it possible to reliably ensure the operating conditions of the device during modernization and changes in production volumes. These results are important for both practical and theoretical purposes. They can be used to accurately predict the operating conditions of equipment during modification and productivity growth. According to the research results, this approach allows obtaining fairly reliable data for forecasting the thermodynamic conditions of the tower equipment in the event of its modernization and transition of the granulation tower to the production of an increased amount of products. The specified method was tested in calculations of production modernization at urea production plants (Indian Farmers Fertilizer Cooperative (Iffco), India), Rustavi Azot LLC (Georgia), Grodno Azot LLC (Republic of Belarus) and others. This method has proven to be quite reliable in predicting the possible need for an additional amount of air supplied to the tower and forming requirements for the operating parameters of rotary vibrating granulators in the event of a significant increase in the load on the float in the tower and an increase in the amount of products planned for release.

The establishment and application of quality gain-loss function when the loss of primary and cubic term is not ignored and the compensation quantity is constant.

The traditional quality gain-loss function(QGLF) considers the case that the primary term loss cannot be ignored, does not consider the cubic term loss, but in practice the cubic term loss should not be ignored. In this paper, based on the existing QGLF model, the Taylor expansion is reserved to the third order, the determination of the quality loss coefficient is discussed and analyzed under the condition that the compensation quantity is constant, and the asymmetric cubic QGLF model is established, and uses an example of concrete mixture out of the machine slump during the dam concrete construction to analyze and discuss the relationship between the proposed model and the traditional quadratic QGLF, which verifies the rationality of the proposed model.

Forecasting Final Cost and Time Rates of Highway Construction Projects in Iraq Using Regression Analysis

The construction process is fraught with risks and uncertainties, which grow in proportion to the size and complexity of the project. The project is considered successful if it is completed within the specified time and cost and with the required quality standards. The time and cost overrun of building projects and highways is a critical issue because of the great risks that result from it, which affect the project completion process and sometimes put it to a halt. In this paper, an attempt was made to predict the final cost rate and final time rate of such projects before starting work, using the technique of reverse elimination regression analysis. The study covers a group of highway projects in Diyala Governorate, where the records of (25) projects that were completed during (2012-2021) were used to develop and validate the regression model. Based on the experts' convictions, there are nine factors that are considered the most influential on the final cost and final time. Hence they are used as input parameters for the form. These factors are; bid cost, bid duration, change order cost, change order duration, final cost, and final duration, no. of change order, start time and final time. It was found that the developed regression model has the ability to predict the final cost rate (FCR) and final duration rate (FDR) for highway projects as outputs with very high goodness of fit and coefficient determination ( ) of (98%) and (96%) for FCR and FDR respective.

Flexural Buckling Resistance of Stiffeners Reinforcing Wall of a Steel Silo

Stiffeners reinforcing silo’s wall made from corrugated sheets are main structural elements sustaining meridional forces evoked by shear forces, source of which is friction of the material stored inside silo. Buckling resistance of stiffeners can be assessed by the method recommended in PN-EN 1993-4-1:2009/A1-2017-08E and in the draft of the Eurocode prEN 1993-4-1:2022. This method consists in determination of stiffener’s resistance treated as a column resting on elastic substrate which is the susceptible wall of the silo. It means that it was assumed that the stiffness of the sheeting resists buckling displacements normal to the silo wall. The procedure recommended in mentioned Eurocodes requires determination of stiffness coefficient K on the basis of the flexibility of an equivalent arch of the span equal to the double circumferential separation between adjacent stiffeners. The stiffness coefficient K was derived in the paper using classical mechanics methods and its value was compared to the one given in mentioned Eurocodes. Careful comparative analyses resulted in the identification of errors in one of the Eurocode formulae, which could result in a significant misestimation of the buckling resistance of the stiffeners. The proposed amendment led to a full correspondence between the final formula for K derived in the paper and that proposed in the referenced Eurocodes. The errors found were reported to the coordinator of the CEN working group updating EN 1993-4-1.