Keresés
Keresési eredmények
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Literature Overall of Fatigue Analysis Approaches of Vehicle Components Made of Rubber
130-140Megtekintések száma:144Generally, the most frequently used structural materials are metals which have high strength and stiffness. However, there are many cases when other important properties come to the front, as well as high deformation capacity with elastic behavior, high viscosity namely good damping effect. Due to its above mentioned properties, rubber is widely used in vehicle and automotive industry. Vehicle components made of rubber usually exhibit large deformations. Cyclic finite deformations generate temperature in hyperelastic materials. Furthermore it is necessary to take into consideration the effects of ambient temperature. The mechanical properties of rubber depend on temperature and temperature changes can accelerate chemical alteration processes which lead to the material deterioration and fatigue processes. Research on fatigue behavior and fatigue properties of rubber has a great significance for predicting fatigue life and improving durability of rubber products. There are several studies on the fatigue behavior of rubber-based materials, but there is less research in the fatigue life prediction considering the influence of temperature and temperature changes. First purpose of this paper is summarizing the influence of temperature and temperature changes on the fatigue behavior of rubber. The second purpose of this study is to provide an overview of the state of the art on the fatigue life prediction of rubber with primary focus on the different methods available for prediction of fatigue life under the influence of temperature and temperature changes.
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Conceptual Design of the Low-Cost Environmental Temperature Test Chamber System
81-94Megtekintések száma:70Unmanned robots being remotely controlled or autonomous are spread worldwide and used in different purposes. Inhabited robots are brought very close to users and accessibility to these tools is very high, moreover, at very low costs. Regardless to emphasize the increasing popularity of these robots. However, any robot system being electrically driven and controlled has bottleneck in the amount of the electrical energy stored aboard in the battery packs. In other words, due to limited amount of the electrical energy available special issues related to use energy best way with maximum effectiveness are needed and considered. Additionally, the battery management system is needed to control the processes of the discharge and the charge ensuring technical data and parameters set by the manufacturer. This paper addresses robot applications in regions out of the calculated when special environmental testing is needed to confirm battery pack technical data. Among those of the environmental tests required the temperature test is in the focus of attention. The main idea and purpose of this paper is to set up new concept of the low-cost environmental temperature test chamber, to define its technical parameters and other properties needed for its preliminary design and prototype manufacturing.
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The Effects of Quenching and Tempering Treatment on the Hardness and Microstructures of a Cold Work Steel
286-294Megtekintések száma:208The X153CrMoV12 ledeburitic chromium steel characteristically has high abrasive wear resistance, due to their high carbon and high chromium contents with a large volume of carbides in the microstructure. This steel quality has high compression strength, excellent deep hardenability and toughness properties, dimensional stability during heat treatment, high resistance to softening at elevated temperatures. The higher hardness of cryogenic treated samples in comparison with conventional quenched samples mean lower quantity of retained austenite as at samples quenched to room temperature and tempered in similar condition. In the microstructure of samples were observed that the primary carbide did not dissolve at 1070°C and their net structure have not been changed during to heat treatment. During to tempering at high temperature the primary carbides have become more and more rounded. After low tempering temperature in martensite were observed some small rounded carbides also, increasing the tempering temperature the quantity of finely dispersed carbides increased, which result higher hardness. The important issues in heat treatment of this steels are the reduction or elimination of retained austenite due to cryogenic treatment.
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Thermoelastic Problems of Multilayered Spherical Pressure Vessels Subjected to Axisymmetric Loading
106-115Megtekintések száma:103This paper deals with the linear thermoelastic analysis of functionally graded multilayered spherical bodies subjected to constant mechanical and thermal loading. The temperature field is arbitrary function of the radial coordinate, the material properties and the radial body force vary according to power law functions along the radius of the sphere. An analytical method is presented to calculate the displacements and stresses within the multilayered spherical body. The method is expanded to tackle the problem of spherical bodies made from radially graded materials with temperature dependent material properties. The results are compared to finite element simulations and other methods.
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Interchange of Heat in Saw Disc Body During Cutting
488-494Megtekintések száma:101The paper presents the experimental results of a research aimed at the distribution of the temperature on the circular saw blade body. The temperature was measured at two distances from the centre of the circular saw blade body (70 mm, 140 mm) by means of an infrared thermometer. Two circular saw blades with the diameter of 350 mm and a variable adjustment of the body (with slots and without the coating, with both slots and coating) were used for the longitudinal sawing of the spruce wood (Picea excelsa) with the thickness of h = 37 mm. Feed speeds ware vf1 = 14 mpm, vf2 = 17 mpm and vf3 = 20 mpm. Cutting revolutions n = 4100 /min. were constant. The measured temperature was in the range from 21 °C till 27 °C. The highest measured temperatures were recorded on the circular saw blade with the slots and coating.
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Egy iroda épület energiatermelő lehetőségeinek vizsgálata, a hőfokgyakorisági görbe felhasználásával
63-67Megtekintések száma:70A cikk és a dolgozat egy Mátészalkai irodaház fűtési energiatermelőjét vizsgálja. A rendszer az
épületben lévő üzlethelyiségek és irodák fűtési energiaigényét hivatott fedezni. Az irodaház hőszükséglete
szoftveres számítás alapján van meghatározva. Az energiaigény meghatározása a hőfokgyakorisági görbe
segítségével történt. A munka erre a konkrét értékre választott kazánokat és hőszivattyúkat vizsgál, és
eredményként azok üzemeltetési költségét hasonlítja össze. -
Analysis of Thermal Degradation in the Annealing Process of Colored Parts Built by Extrusion-Based 3D Printing
124-133Megtekintések száma:358With the ever-increasing request of light materials, poly lactic (acid) PLA, have got much in consideration. Low-cost PLA materials have risen its use. Those possess some benefits but nevertheless insufficient mechanical strength. The printed PLA objects have a stumbling block for practical applications. Thus, annealing is an interested alternative to make 3D printed objects strong. This thermal treatment can significantly develop investigational studies and offer technical data. Hence the purpose of this paper is study and discuss how to increase the flexural strength through annealing process. Geometry distortions and color degradation will be analyzed. Differential Scanning Calorimetry, Taguchi Method (TM) and variance (ANOVA) were applied as part of the design experiments and analysis. Twenty-seven printed specimens were tested and factors as temperature, time and color were selected.
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Synthesis of Polylactic Acid (PLA) by Polycondensation Method
286-293Megtekintések száma:305The Polylactic acid (PLA) is compostable and natural renewable sourced plastic type. Its mechanical properties quite similar to the PET, therefore the PLA is a good alternative for strongly ruled food industrial application. The PLA only has one critical attribute – the relatively low glass transition temperature. According to the relevant literature the glass transition of PLA is in the range of 40-70°C. In light of this fact, this material can be used only in that segments of food industrial field where the packaging process temperature are under of the lower limit of Tg range. The actual Tg of a material is highly depends on the molar mass and material structure, therefore the molar mass and the structure of material should be designed according to the future requirements of application and procedures.
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Potentiodynamic Study of the Effects of Nickel on The Electrodeposition of Zinc from Chloride Media
15-24Megtekintések száma:106Abstract. The potentiodynamic experiments of the nickel effects on the zinc electrodeposition have been done to understand the impact of Ni impurities on the electrowinning of Zn from spent pickling liquor. The nickel chloride solutions of Ni concentrations 90 and 1 g/dm3 were used as the electrolytes. The latter was also mixed with 90 g/dm3 Zn in the experiments. All the runs were carried out at room temperature with 40 mV/s continuous polarization speed and with 1/s sampling rate. It was observed that nickel electrodeposition from chloride media containing 90 g/dm3 Ni started with the generation of hydrogen bubbles, entirely blocking the cathode surface. Only a slight current development was observed until the polarization potential ~ -0,8 V. The visual observation showed bubbles also formed at the anode, which may represent chlorine and/or oxygen evolution. While, in the electrodeposition of nickel with only 1 g/dm3 Ni concentration in the electrolyte, metal deposition was hardly observed, but visible hydrogen bubbles constantly blocked the cathode surface. A similar tendency was observed in the mixed-solution electrolysis cell; the initial tiny bubbles accumulated at the cathode surface more than in the pure Zn solution. The enhancement of H2 evolution indicates how nickel deposition may contribute to the loss of useful current in the process of Zn electrodeposition. The mass of nickel deposited from the mixed solutions significantly decreases as the Ni concentration decreases in the electrolyte, while the mass of deposited zinc is relatively constant. It means that the purity of the produced Zn is appreciably higher – with respect to Ni – if nickel is efficiently eliminated from the solution before electrowinning.
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The Effect of annealing temperature on corrosion resistance and microstructure of Zr-Sn-Nb-Fe alloy
420-424Megtekintések száma:101The Ti-2Al-2.5Zr titanium alloy plate in beta phase water quench at different times of the reentry after annealing is implemented while primary phase number and size distribution of samples are obtained. This research is carried out on corrosion behavior in 3.5% [mass fraction] NaCl solution. Experimental study showed that after the beta phase water quenching Ti-2Al-2.5Zr titanium alloyed after 500 oC annealing when partial recrystallization happened. There seems to be lots of tiny dispersion in the alloy that was annealed with its samples of six-party [HCP] structure of Ti, Zr, Al phase 2 with the dimension below 100 nm. Reaching 500 oC when the rate of annealing at a primary phase of the sample at 550 oC is low 90% of the primary phase is less than 100 nm. The changing of the rule of present decreasing also triggers little difference overall. Precipitation in the process of annealing Zr [Nb,Fe,Cr] 2is less that proves to be good for corrosion resistance.
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The Effect of Fluxes on the Melt Quality of AlSi7MgCu Alloy
372-380Megtekintések száma:183The presence of inclusions such as oxides, carbides or refractory particles can be harmful to the mechanical and surface characteristics of castings. Inclusion-rich metals result in lower fluidity and feeding capability during casting. Nowadays, solid fluxes are widely used in foundries in order to reduce the inclusion content of aluminium melts. In this study, the effect of four different fluxes on the melt quality was studied. First, the inclusion content of the flux-treated melt, and then the properties of the fluxes (i.e. chemical composition and melting temperature) were examined.
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Geotermikus energia hasznosíthatósági lehetőségei a Bükkalja térségében meddő szénhidrogén termelő kutak átképzésével
351-357Megtekintések száma:270Magyarország egy nem aktív vulkáni területen fekvő, ám mind európai,- mind pedig nemzetközi szinten elismert geotermikus potenciállal rendelkező ország. Az ország geotermikus gradiense átlagosan, ~ 45°C/km, míg más országokban ez az érték, ~ 20-30°C/km. Ennek megfelelően a hőmérséklet 1km-en 55-60°C, 2 km mélységben akár a 100-130 °C-ot is elérheti. A geotermikus energia kinyerésének és hasznosításának sok fajtája létezik, melynek egy nagy csoportját képezi az energetikai hőhasznosítás. Ez az irány itthon nem jellemző, így ezt a vonalat érdemes fejleszteni. Az ágazat fejlődése lassú, ennek fő oka a nagy kezdeti befektetési igény valamint a hosszú tervezési szakasz. Kutatásunk célja egyrészt ezen probléma orvoslásának irányában igyekszik lépéseket tenni, egy meddő kút funkcióváltását vizsgálva. A Bükk hegység előterében, peremi területein számos meddő, használaton kívüli szénhidrogén kút van melyeket munkánk energetikai céllal a későbbi hasznosíthatóság tükrében vizsgál. Jelen vizsgálat, Bükkalja, Demjén, Pünkösd-hegy térségében található 13 db felhagyott kútra koncentrál.
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Geotermikus energia korszerű felhasználása Nagyszénás településen (Esettanulmány)
106-115Megtekintések száma:178Békés megyében található Nagyszénás településen geotermikus energiafelhasználásra épülő projekt került átadásra 2015. december 20.-án. Az építési beruházások az Európai Unió támogatásával a 2007-2013-ös pénzügyi, finanszírozási ciklusban elnyert pályázati forrásból valósultak meg 1,578 milliárd forint összértékben. A termálvíz-hasznosítási beruházás országos viszonylatban is egyedülálló műszaki megoldásokkal valósult meg és eredményeképpen a meglévő geotermikus lehetőségek kihasználásával, zöld energiaforrásra épülő, korszerű, gazdaságos fűtési rendszer lett kiépítve a település közintézményeiben és az újonnan létesített parkfürdő-komplexumban. A kivitelezés során és az üzemeltetés közben, számos előre nem ismert műszaki probléma merült fel, amelyek megoldása csak új technikai elemek alkalmazásával vált lehetővé. A kitermelt termálvíz magas sótartalma és a magas hőfoka különleges gépészeti és építészeti megoldásokat követelt. Az üzemeltetés során számos ponton átalakításra és technológiai elemek megváltoztatására volt szükség a biztonságos üzemeltetés érdekében. A cikk célja ezen műszaki beavatkozások bemutatása, amelyek eredményeképpen napjainkban a rendszer megbízhatóan üzemel, és megfelelő alternatívát nyújt a földgáz hátterű fűtési rendszerek helyett.
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Adaptability of Powdered Activated Carbon Production from Ground Catering Waste Pyrolysis Coke
162-171Megtekintések száma:108Three mixture of catering waste was pyrolyzed at 650, 725 and 900 °C and the solid residue (coke) was examined for powdered activated carbon production. For this, the carbon content, iodine number, particle size distribution and scanning electron microscopic images were analysed. Based on the carbon content, these cokes are suitable for activated carbon production, which were 60-85 wt.% (depending on the base material and pyrolysis temperature). The studied cokes showed slightly porous structure with smooth surfaces. Because of this, the iodine number was mostly small (13-30). Based on the grinding experiments, 10 minutes of grinding was found to be optimal. After this grinding time, the reached iodine number of powdered activated carbon was 350-610.
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Testing of Micro Switches for Garden Tools
206-213Megtekintések száma:84The aim of this paper is to introduce the design of testing method for the prediction of the life and acceleration methods of the micro switches applied in different type of garden tools. These products will be tested for complex stressing, for example higher temperature, humidity, current load and so on. Therefore, the most important information and multi-factor acceleration models are summarized, the Weibull, the lognormal and the exponential distributions which are suitable for performing and evaluating tests.
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A homlokmarási technológia hőkamerás elemzése a fordulatszám változtatása mellett
142-147Megtekintések száma:103A publikáció célkitűzése homlokmarási technológia során a forgácsleválasztáskor képződő hőmérsékleti zóna vizsgálata hőkamerával. A vizsgálatot diszkrét fordulatszám értékek változtatásával a többi technológiai paraméter állandóssága mellett végezzük el. Megtervezzük a mérési koncepciót. A kísérletek elvégezte után elemezzük a kapott hőképeket.
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Numerical Model Analysis of Natural Gas Combustion Burners
67-71Megtekintések száma:116Traditional power plants still the dominating power source for all the major industries and powerdemanding facilities, the most crucial facility for the whole plant operations is the industrial boiler which generatessteam, heating energy or electrical power. Boilers generate energy by combustion. The improvement of combustion efficiency could greatly influence the energy consumption and will make the boiler more efficient and cleaner (less emissions), that’s why it is important to understand the combustion and thermal flow behaviours inside the boiler. Beside experimental testing, computational work nowadays becoming more and more important due to lower cost and acceptable accuracy with minimum error. With numerical calculations method, the computational model created by a Computational Fluid Dynamics (CFD) software could reduce a lot of trial and error on experimental work. In this paper utilizing the ANSYS FLUENT 19.1 software to make crate the combustion model. The ratio of air to fuel mixture, the equivalency factor, mass flow rate of the mixture, velocity, mass fractions of the mixture components (fuel and air) and their temperatures will serve as the input parameter while the exhaust gase component mass fraction, temperature, mass flow and velocity will be monitored.
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Boundary Value Problem for a Heated Nanofluid Flow in the Presence of Magnetic Field
58-66Megtekintések száma:78The aim of this paper is to introduce some new numerical results on the magneto-thermomechanical interaction between heated viscous incompressible magnetic nanofluid and a cold wall in the presence of a spatially varying magnetic field. The governing nonlinear boundary layer equations are converted into coupled nonlinear ordinary differential equations by similarity transformation. The ODE system is solvable numerically for example using higher derivative method. The investigation is focused on the influence of governing parameters corresponding to various physical conditions. Numerical results are exhibited for the dimensionless wall skin friction and for heat transfer coefficients at the wall, along to distributions of the velocity and the temperature.
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Modeling the Thermal Behavior of Permanent Magnet Synchronous Motors
466-477Megtekintések száma:132The aim of this study is to present a thermal analysis of a permanent magnet synchronous machine based on finite element method. The developed model can be used to predict temperature distribution inside the studied motor during the rated operation. Electromagnetic computation is carried out with the aid of two 2D finite-element (FE) simulations on the cross-section of the PM motor. To analyse the process of heat transfer in an electrical machine, empirical correlations are used to describe the convective heat transfer from the different surfaces of the PM motor. The heat transfer coefficient is determined using dimensionless numbers and Nusselt number. After the loss calculation, the temperatures of the machine are calculated by using 3D finite element method. The results obtained by the model are compared with experimental results from testing the prototype electric motor.
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Ivóvízminták mikrobiológiai és kémiai vizsgálata a Pannon-Víz Zrt. működési területén
151-160Megtekintések száma:199Tanulmányunkban a Pannon-Víz Zrt. működési területén 2015. január 1. - 2017. október 31. közötti időszakban követtük nyomon az ivóvízminőség változását. A környezeti hőmérséklet változása, a mikrobiológiai terheltség és az egyes kémiai paraméterek értékei között kerestünk összefüggést. Az adatok kiértékelését követően az alábbiakat állapítottuk meg. A mikrobiológiai pozitív minták szezonális változásait az Escherichia coli és Enterococcus baktériumok, illetve a Pseudomonas aeruginosa szennyezettség alapján lehetett meghatározni. A coliform baktériumcsoport és a 22°C-os, 37°C-os telepszám megjelenése nem mutatott szezonális dinamikát. Az elemzett kémiai paraméterek a vizsgált időszakban mindig határérték alatt maradtak. A kémiai és a mikrobiológiai paraméterek közötti összefüggés feltárására alkalmazott korreláció analízis alapján a vizsgált paraméterek között nem adható meg kapcsolat.
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Designing of Lab-scale Anaerobic Digester Equipped with Maxblend Impeller to Evaluate Effect of Mixing on Anaerobic Digestion
404-413Megtekintések száma:134Operational parameters can be easily controlled at lab scale experiments for an anaerobic digestion process. Our aim is to design a lab-scale digester equipped with an impeller to investigate how the geometry of impeller and different mixing modes effect the biogas yield of digester. Further, the methods of measuring the gas volume, gas composition, mixing intensity, torque, temperature are discussed in this article. The assembling of 4 liters digester is described which can be operated at various operating parameters which control the anaerobic digestion process. Mixing is very important to enhance efficiency of an anaerobic digester. To attain mixing Maxblend impeller is used in this lab-scale digester due to its better performance for mixing and power consumption. Various design consideration has been described.
