Rationalization of a Core Warehouse in the Casting Plant: A Case Study

The warehouse is an important factor in the manufacturing process. At present, there are constant demands for the more efficient and effective operation of warehouse systems. For this reason, the rationalization of existing warehouses and/or storage systems is one of the ways to achieve the previously set targets. The possibilities of rationalization are numerous in all segments of the observed system. The most suitable solutions for a particular warehouse will be found based on the nature of the observed problem and the available investment funds. The paper defines the place and the role of the warehouse in a casting plant. Besides, the current situation in the warehouse segment of casting plants is analyzed to identify problems. Finally, the development of different concepts of rationalization to relevant constraints is discussed. This approach has enabled us to solve the problem of the rationalization task and to produce the desired effects

Quantification of Feeding Regions of Hypoeutectic Al-(5, 7, 9)Si-(0-4)Cu (wt.%) Alloys Using Cooling Curve Analysis

This chapter presents the potential of the cooling curve analysis to characterize the solidification path of the cast hypoeutectic series of Al-Si-Cu alloys and to quantify their feeding regions. The aim of this work is to examine how variations in the chemical composition of Si (5, 7 and 9 wt.%) and Cu (from 0 to 4 wt.%) might affect the characteristic solidification temperatures, their corresponding fraction solid, and feeding regions of investigated alloys. These parameters collected from the cooling curve analysis can be used for better understanding of the solidification paths of Al-Si-Cu alloys and could easily be incorporated into existing simulation software packages to improve their accuracy

From Bauxite as a Critical Material to the Required Properties of Cast Aluminum Alloys for Use in Electro Automotive Parts

There is a long process to transform bauxite, a critical raw material, into a substance with the required properties of cast aluminum alloys for use in electro automotive parts. Thanks to its unique properties, aluminum has become the material of choice for clean technology manufacturers in applications such as use in the automotive industry, renewable energy, batteries, electrical systems, resource-saving packaging, energy efficient buildings and clean mobility. Restructuring of the economy, the oil crisis, air pollution and global warming are some of the factors that have moved the automotive industry towards electrification since the beginning of the 21st century. This paper aims to highlight the required properties of cast aluminum alloys applied to the production of electro automotive parts, such as their mechanical and thermophysical properties, dimensional stability, corrosion resistance, electromagnetic compatibility and crashworthiness. Furthermore, this paper discusses which of the cast aluminum–silicon alloys, as well as the heat treatments and casting processes, are most suitable

Thermodynamic analysis and characterization of phase-change alloys based on bismuth and gallium

Fazno-promenljivi materijali za akumulaciju toplote predstavljaju vrlo važnu grupu funkcionalnih materijala koji imaju široku primenu u različitim industrijskim oblastima. Glavna karakteristika ovih materijala je velika količina latentne toplote koja se apsorbuje ili oslobađa na približno konstantnoj temperaturi usled dešavanja povratne fazne transformacije u samom materijalu. Veliki broj organskih i neorganskih materijala je do sada ispitivan i komercijalno primenjen u oblasti fazno-promenljivih materijala za akumulaciju toplote. Poslednjih godina vrše se intenzivna istraživanja metalnih materijala kao potencijalnih fazno-promenljivih materijala. Glavne prednosti metalnih fazno-promenljivih materijala u odnosu na druge tipove materijala su njihova visoka toplotna provodljivost i velika količina latentne toplote topljenja po jedinici zapremine. Predmet ispitivanja u okviru ove doktorske disertacije su niskotopive eutektičke legure na bazi bizmuta i galijuma koje spadaju u metalne materijale sa najvećim potencijalom primene u srednjem i niskom temperaturnom opsegu rada fazno-promenljivih materijala. U doktorskoj disertaciji je izvršen termodinamički proračun i eksperimentalno određivanje mikrostrukturnih karakteristika i termičkih osobina poput temperature topljenja, latentne toplote topljenja i toplotne provodljivosti eutektičkih legura iz Bi-In, Bi-Sn, Bi-In-Sn i Bi-Sn-Zn sistema na bazi bizmuta kao i Ga-In i Ga-Sn sistema na bazi galijuma. Dobijeni rezultati će doprineti boljem poznavanju osobina metalnih fazno-promenljivih materijala za akumulaciju toplote i proširiti postojeći fond fundamentalnih i praktičnih znanja o ispitivanoj grupi funkcionalnih metalnih materijala na bazi bizmuta i galijuma.Phase change materials (PCMs) for thermal energy storage represent a very important group of functional materials that have wide application in different industrial areas. The main characteristic of these materials is the large amount of latent heat that is absorbed or released at approximately constant temperature due to the occurrence of a reverse phase transformation in the material itself. So far, a large number of organic and inorganic materials have been tested and commercially applied in the field of phase-changeable heat accumulation materials. In recent years, intensive research of metal materials as a potential phase-change materials has been carried out. The main advantages of metallic phase-change materials in relation to other types of materials are their high thermal conductivity and a large amount of latent heat dissipation per unit volume. The low-melting eutectic alloys based on bismuth and gallium that belong to metal materials with the greatest potential for application in the medium and low temperature range of phase-change materials are the subject of this doctoral thesis. In the doctoral dissertation a thermodynamic calculation and experimental determination of microstructural characteristics and thermal properties such as melting temperature, latent heat of melting and thermal conductivity of eutectic alloys from the Bi-In, Bi-Sn, Bi-In-Sn and Bi-Sn-Zn systems based on bismuth as well as Ga-In and Ga-Sn systems based on gallium is carried out. The obtained results will contribute to a better knowledge of the properties of metallic phase-change materials for thermal energy storage and expand the existing fund of fundamental and practical knowledge about the examined group of functional metallic materials based on bismuth and gallium

I nterpreting the achievement of entrepreneurs: attributional approach

Istraživanje na temu provere Vajnerovog atribucionog modela u oblasti preduzetništva u Vojvodini i Beogradu sprovedeno je u periodu od 2016.-2017. godine. Terenskim istraživanjem putem online i offline ankete ispitano je 140 preduzetnica i preduzetnika koji posluju pretežno u oblasti usluga. U radu je dat istorijski pregled razvoja atribucionih teorija, a zatim i mnogobrojnih istraživanja iz oblasti kognitivne psihologije preduzetništva. Kao osnovni problem istraživanja postavljeno je sledeće pitanje: da li je Vajnerov model atribucije postignuća primenjiv u analizi tumačenja postignuća preduzetnika? Osnovna pretpostavka našeg pristupa glasi: način tumačenja postignuća preduzetnika ima svoje kognitivne i emocionalne posledice u vidu očekivanja o budućem angažovanju i emocija koje podstiču intenzitet i kvalitet motivacije za bavljenje preduzetništvom u budućnosti. Kao dodatni cilj istraživanja postavljeno je i testiranje modela atribucije preduzetnika koji je, u poređenju sa klasičnim Vajnerovim modelom atribucije, bio obogaćen varijablama koje mogu sistematski oblikovati proces tumačenja postignuća, kao što su motiv osnivanja preduzeća, preduzetnička samoefikasnost, lične vrednosti preduzetnika i percepcija poželjnosti preduzetništva u društvu. U istraživanju je korišćena baterija instrumenata koja sadrži modifikovane skale stavova o preduzetništvu, originalnu Švarcovu skalu ličnih vrednosti i dva instrumenta namenjenih merenju atribucije uspeha i neuspeha konstruisana za potrebe istraživanja, i konačno, sociodemografski upitnik o preduzeću i ispitaniku. Dobijeni rezultati istraživanja potvrdili su 10 i opovrgnuli osam početnih pretpostavki. Sprovedeno istraživanje dalo je važne rezultateo atribucionom pristupu u kontekstu preduzetništva, doprinelo rašćišćavanju brojnih rezultata ranije sprovedenih istraživanja u oblasti preduzetništva u tranzicionim zemljama, potvrdilo konstruktivnu, konvergentnu i divergentnu valjanost novokonstruisanih instrumenata i na kraju, bacilli malo, ali jako svetlo na preduzetničku praksu u našoj zemlji.The research on the topic of the Weiner's attribution model in the field of entrepreneurship in Vojvodina and Belgrade was conducted in the period from 2016 to year of 2017. Field survey through online and offline questionaire examined 140 female and male entrepreneurs who work predominantly in the field of services. The paper presents a historical overview of the development of attribution theories, continuing with numerous studies in the field of cognitive psychology of entrepreneurship. As the main problem of research we raised the following question: whether the Weiner attribute attribute achievement is applicable in the analysis of the interpretation of entrepreneurial achievements? The basic hypotezys of our approach is: the way of interpreting the achievement of entrepreneurs has its cognitive and emotional consequences in the form of expectations about future engagement and emotions that stimulate the intensity and quality of motivation to engage in entrepreneurship in the future. As an additional objective of the research, comparing with the classical Weiner’s model of attribution, the model of entrepreneurial attribution model was set up, which was enriched with variables that can systematically form the process of interpretation of achievements, such as the motive of founding enterprise, entrepreneurial self-efficacy, personal values of entrepreneurs and perceptions of the desirability of entrepreneurship in society. In the research we used a battery of scales containing modified scales of entrepreneurial attitudes, Schwartz’s original personal values scale and two instruments constructed to measure the attribution of success and failure designed for research, and finally, a sociodemographic questionnaire about the company and the respondent.The obtained results of the survey confirmed 10 and disproved eight initial hypotheses. The conducted research gave important results on the usefullness of attribution approach in the context of entrepreneurship, contributed to the clearing of numerous results of previously conducted research in the field of entrepreneurship in transitional countries, confirmed the constructive, convergent and divergent validity of newly constructed instruments, and finally, the threw little, but very bright light on entrepreneurial practices in our country

Casting Process Improvement by the Application of Artificial Intelligence

On the way to building smart factories as the vision of Industry 4.0, the casting process stands out as a specific manufacturing process due to its diversity and complexity. One of the segments of smart foundry design is the application of artificial intelligence in the improvement of the casting process. This paper presents an overview of the conducted research studies, which deal with the application of artificial intelligence in the improvement of the casting process. In the review, 37 studies were analyzed over the last 15 years, with a clear indication of the type of casting process, the field of application of artificial intelligence techniques, and the benefits that artificial intelligence brought. The goals of this paper are to bring to attention the great possibilities of the application of artificial intelligence for the improvement of manufacturing processes in foundries, and to encourage new ideas among researchers and engineers

Application of Machine Learning in the Control of Metal Melting Production Process

Abstract This paper presents the application of machine learning in the control of the metal melting process. Metal melting is a dynamic production process characterized by nonlinear relations between process parameters. In this particular case, the subject of research is the production of white cast iron. Two supervised machine learning algorithms have been applied: the neural network and the support vector regression. The goal of their application is the prediction of the amount of alloying additives in order to obtain the desired chemical composition of white cast iron. The neural network model provided better results than the support vector regression model in the training and testing phases, which qualifies it to be used in the control of the white cast iron production

ECO-FRIENDLY ELDERBERRY BASED SORBENT FOR REMOVING Pb2+IONS FROM AQUEOUS SOLUTIONS

Abstract Elderberry (Sambucus nigra) pith was modified with polyethyleneimine (PEI) in order to improve the adsorption properties. Characterization of both dried Sambucus nigra pith (DSNP) and amino modification of elderberry pith with branched PEI (PEI/DSNP) was performed by: Fourier-transform infrared spectroscopy (FTIR), optical microscopy, and porosity determination. The amine and ester number, as well as acid value, were determined on DSNP and PEI/DSNP samples using standard volumetric methods. The samples were used as adsorbents for Pb2+ions from an aqueous solution in a batch system. The obtained results were fitted using suitable equilibrium isotherm and kinetic models. The maximum adsorption capacity for Pb2+ions on DSNP andaminаted sample, obtained using Langmuir adsorption isotherm at 298 K, are 18.9 and 47.8 mg g-1, respectively. Based on the kinetic studies, the adsorption process follows the pseudo second-order model. Thermodynamic parameters showed that the adsorption process is endothermic and spontaneous. In general, the overall adsorption process was improved by modifying starting material withbranched PEI modifier by introducing large numbers of amino functionalities having high affinity to cations

Impact of major alloying elements on the solodification parameters of cast hypoeutectic AlSi6Cu (1–4 wt.%) and AlSi8Cu(1−4 wt.%) alloys

The present work displays the potential of cooling curve analysis to characterize the solidification path of cast hypoeutectic series of Al-Si6-Cu(1−4 wt.%) and Al-Si8- Cu(1−4 wt.%) alloys. The aim of this work was to examine how variation in chemical composition of silicon and copper may affect characteristic solidification temperatures, fraction solid, and thermal freezing range of investigated alloys. Eight different Al−Si−Cu alloys (Al-Si6-Cu1, Al-Si6-Cu2, Al-Si6-Cu3, Al-Si6-Cu4, Al-Si8-Cu1, AlSi8-Cu2, Al-Si8-Cu3 and Al-Si8-Cu4) have been analyzed applying cooling curve analysis technique. Characteristic solidification temperatures have been determined using cooling curves or their corresponding first derivative curves along with ΔT curves. Fraction solid curves determined from recorded cooling curves have been used to calculate terminal freezing range and estimate crack susceptibility coefficient for each alloy. Theoretical mode for prediction of the cracking susceptibility coefficient developed by Clyne and Davies has been considered in this work. In addition, a novel mathematical model for prediction of crack susceptibility coefficient based on data collected from cooling curve analysis has been proposed. http://dx.doi.org/10.5937/metmateng1404235