bluuebunny/crossref_metadata_2025 huggingface dataset:
Biodegradation of Sulphide in Biogas by Biofilm on Salak Fruit Seeds: Accuracy of Quasi-steady-state Approximation
Authors: Lestari Retno A. S. , Sediawan Wahyudi B. , Sarto
Published: March 2018

This study tried to explore the quantitative description of removal of hydroden sulphide (H2S) by bio-filtration. H2S is degraded by bacteria immobilized on the packing materials of Salak fruit seeds inside a column. Two kinetics models are proposed. In both models, the biofilm formed on the packing material is assumed to be thin, so intra-film gradient of H2S concentration can be neglected. In model 1, material balances of H2S in the bio-film as well as in the flowing gas are set-up. The growth of the bio-film is modelled by Monod’s equation. A set of three simultaneous partial differential equations are obtained. Model 2 is set-up using the same concepts as in model1, but the gas phase is assumed to be quasi-steady-state. This assumption reduces the partial differential equation in model 1 to be an ordinary differential equation which is easier to be solved. The comparisons of the results of model 1 and model 2 can be applied to justify the applications of quasi-steady-state approximation. It turned out that the differences of calculated H2S concentration results are approximately small, around 6 ppm. Hence, it can be concluded that quasi-steady-state approximation in the gas phase is suggested to be applied.
Ozonation of Yarn dyed Wastewater in a Continous Stirred Tank Reactor : Kinetic Study and Performance Optimisation
Authors: Riadi Lieke , Sugiharto Andrian , Gondokusumo Hana
Published: March 2018

This paper describes the ozonation process in yarn dyed wastewater using continuous stirred tank reactor with the objective to study the kinetic of COD degradation at various volumetric flow rate (30, 50, 70 ml/min) and ozone concentration (2.70 %, 4.25%, 5.86 % mol/mol). The wastewater which was collected from a yarn dying process located in Surabaya area was pretreated by electrocoagulation prior to ozonation process. The electrocoagulation process was carried out to reduce the color intensity and total suspended solid. The pretreated wastewater was then processed using ozonation for 2.5 hours. The result showed that at various concentration of ozone, maximum COD removal was 90.78% which was achieved at 5.86 %mol/mol of Ozon and volumetric flow rate 50 ml/min. It was found that the degradation process followed the pseudo-first order kinetic model. The obtained pseudo-first order rate constants for volumetric rate of 50 mil/min were 0.0307 min-1, 0.0419 min-1 and 0.053 min-1 for ozon concentration of 2.70 %, 4.25%, 5.86 % mol/mol respectively. The residence time were 41 minutes, 31 minutes and 23 minutes for ozone concentration of 2.70 %, 4.25%, 5.86 % mol/mol respectively. These findings offers an alternative treatment for wastewater containing dyes.
Low Rank Coal Pre-treatment to Increase Its Reactivity Towards Gasification with Biomass
Authors: Rizkiana Jenny , Pranata Ryzka , Fauzi Hasna Nisrina , Wulandari Winny , Sasongko Dwiwahju
Published: March 2018

Coal can be used to produce hydrogen through steam gasification process. Indonesia has abundant coal reserves and thus hydrogen production from coal is very attractive. However, steam gasification of coal usually requires high temperature due to its low volatile content. The use of catalyst, such as alkaline and alkaline earth metal (AAEM) may promote the hydrogen production. AAEM metal can be found in biomass and thus co-gasification of coal and biomass may become the attractive solution as the AAEM may volatilize during gasification and catalyze the coal when it attaches to the coal surface. However, the presence of silicate may decrease catalytic activity of the attached AAEM and thus it needs to be removed by deashing process. This research aims to determine the effect of the solution type, solution concentration, reaction temperature, and reaction time of coal deashing. The results showed that deashing process decreased the ash content of coal to some extent proved by the gravimetric analysis result. The decrease of ash content also affected to the surface morphology of the coal as some pores are formed and thus the surface area of coal increased slightly. The increase of surface area allows more AAEM to be attached to the coal surface so that the coal may become more reactive towards steam gasification.
Effect of blending ratio to the liquid product on co-pyrolysis of low rank coal and oil palm empty fruit bunch
Authors: Zullaikah Siti , Lenggono Ari Suryo , Nury Dennis Farina , Rachimoellah M.
Published: March 2018

The utilization of Indonesia low rank coal should be maximized, since the source of Indonesia law rank coals were abundant. Pyrolysis of this coal can produce liquid product which can be utilized as fuel and chemical feedstocks. The yield of liquid product is still low due to lower of comparison H/C. Since coal is non-renewable source, an effort of coal saving and to mitigate the production of greenhouse gases, biomass such as oil palm empty fruit bunch (EFB) would added as co-feeding. EFB could act as hydrogen donor in co-pyrolysis to increase liquid product. Co-pyrolysis of Indonesia low rank coal and EFB were studied in a drop tube reactor under the certain temperature (t= 500 °C) and time (t= 1 h) used N2 as purge gas. The effect of blending ratios of coal/EFB (100/0, 75/25, 50/50, 25/75 and 0/100%, w/w %) on the yield and composition of liquid product were studied systematically. The results showed that the higher blending ratio, the yield of liquid product and gas obtained increased, while the char decreased. The highest yield of liquid product (28,62 %) was obtained used blending ratio of coal/EFB = 25/75, w/w%. Tar composition obtained in this ratio is phenol, polycyclic aromatic hydrocarbons, alkanes, acids, esters.
Biogas Production from Palm Oil Fruit Bunch in Anaerobic Biodigester through Liquid State (LS-AD) and Solid State (SS-AD) Method
Authors: Jos Bakti , Farhan Hanif , Ayu Nadia Dwi , Budiyono  , Sumardiono Siswo
Published: March 2018

The crucial problem facing the world today is energy resources. Waste production of palm oil fruit bunch potentially produce as renewable energy resource. Palm oil fruit bunch contains 44% cellulose, 18% lignin and 34% hemicellulose. Organic carbon source is contained in biomass potentially produce biogas. Biogas is one of alternative energy, which is environmentally friendly and has been widely developed. This research is aimed to examine the effect of pretreatment in raw material of waste palm oil fruit bunch for the production of biogas, the effect of time, ratio C/N, and effect of microbial consortium. The variables are total solid (TS) used 10% and 18% with a 40 mesh physical pretreatment, chemical pretreatment with NaOH 8% gr / gr TS, and biology 5% g/vol with microbial consortium. Biogas production process was conducted over 2 months in room temperature, the test response quantitative results in the form of biogas volume every 2 days and also flame test. The result of this research shows that the highest daily production rate of biogas obtained from this study was 5,73 ml/gr TS and the highest biogas production accumulation generated at 58,28 ml/gr TS produced through a 40 mesh sieve of waste oil palm empty fruit bunch, immersion in NaOH, through solid state fermentation and C/N 30. From this research, it can be concluded that the optimum production of biogas formation occurs with the value of C/N 30, physical and biological pretreatment, and solid state method.
Biogas Productivity as Renewable Energy and Performance of Waste Water Treatment in Tofu Small Scale Industry using an AnSBR Reactor
Authors: Setyowati Rahayu Suparni , Prasetyo Totok , Purwanto Purwanto , Budiyono Budiyono
Published: March 2018

A research that analyzed the relationship between biogas production as renewable energy and performance of waste water treatment in tofu small industry using AnSBR reactor has been conducted. This research used system operation method in batches in to get a description of how the biogas production system works as it was operated in the batch mode, which is applied in tofu industry. An instrument capable of operation in batch mode using AnSBR reactor was designed as it does not require sludge re-circulation. An AnSBR reactor includes five stages of; filling, reaction, settling, decanting, and stabilization (idling state). The research was run for 24 days using biogas collected in a tank. Biogas was measured for each HRT starting on the second day HRT to 24th day HRT. Biogas characteristics were monitored on day 16th for contents of CH4, CO2 and heat value. Results show that CH4 content in the biogas amounts to 78.26 %, while CO2 comprises 20.16 %. Meanwhile, the heat value, which depends on acid methane and CO2 content, is 4,246.55 kkal/kg.
Study of C/N Ratio Effect on Biogas Production of Carica Solid Waste by SS-AD Method And LS-AD
Authors: Jos Bakti , Hundagi Fariha , Pindy Wisudawati Rizqi , Budiyono  , Sumardiono Siswo
Published: March 2018

Biogas is a renewable energy which can be used as an alternative source to replace fossil fuels. Recently, the use of energy has become an important issue because the oil sources and natural gas are depleting. Utilization of carica waste to produce biogas can reduce the consumption of commercial energy sources such as kerosene as well as the use of firewood. Biogas is produced by the process of organic material digestion by certain anaerobic bacterial activity in anaerobic digester. In this study we studied the influence of LS-AD and SS-AD methods, the effect of C / N ratio on biogas yield obtained and kinetics of biogas production reaction. The study was conducted by making a total solid variation of 7%, 9%, 11%, 13%, 19%, 21%, 23% and C/N ratio 25 and 30. The study started with carica waste collection process and examination of the total composition of solids and water content. Thereafter, calculation and determination of variation of C / N ratio by mixing the substrate with inoculum and urea into the reactor. Observe the volume of biogas produced every two-day intervals. The highest biogas production rate of 1.7825 ml/g TS day was obtained from carica solid waste variable by liquid state anaerobic disgestion and C/N 25.
Effect of MWCNT Filler on Properties and Flux of Chitosan/ PEG based Nanocomposites Membranes
Authors: Khoerunnisa Fitri , Hendrawan  , Primastari Dwi Rizki , Agiawati Riska
Published: March 2018

Biopolymer are expected to be environmentally compatible and to have great potential application as membranes material. The chitosan-poly (ethylene glycol)/PEG based composite membranes was successfully synthesized via inversed phase method. The effect of multiwalled carbon nanotubes (MWCNT) as nanofiller on properties and performances of composite membranes were intensively evaluated. The membrane was prepared by mixing of chitosan and PEG solutions at the same composition ratio while MWCNT amount in the mixture was varied. The synthesized membrane was characterized by means of FTIR spectroscopy, scanning electron microscopy (SEM), contact angle, and tensile strength measurement. The performance of composite membrane on filtration was evaluated in term of flux (permeability) and rejection (rejection) tests. The results showed that the optimum volume ratio of composite membrane solution was found at 30:10:7.5 for chitosan/ PEG/ MWCNT, respectively, as indicated by the largest flux. Insertion of MWCNT nanofiller notably enhanced hydrophilicity, porosity, and mechanical properties of composites membranes that are confirmed by contact angle, SEM images and elongation forces value, respectively. The MWCNT nanofiller remarkably increased both of flux and rejection of composite membranes up to 60 Lm2h-1 and 96%, respectively. The remarkable enhancement of composite membrane performance is attributed to the effective interaction of MWCNT with polymeric matrix.
Mass Balances and Thermodynamics Study of Thermal Triglyceride Hydrolysis
Authors: Istyami Astri Nur , Soerawidjaja Tatang Hernas , Prakoso Tirto
Published: March 2018

Triglyceride hydrolysis is a process to convert triglyceride into fatty acids and glycerol, which are important precursors in oleochemical industry. Commercial technology of triglyceride hydrolysis established at the present time is thermal hydrolysis (a.k.a. Colgate-Emery process), which operates in robust condition (250°C, 50 bar). Although this technology has been the most preferable process to produce fatty acid for a century, but information published about its process parameters is limited. In this study, an analysis of mass balances and thermodynamic aspects of thermal hydrolysis of triglyceride was performed based on literature review. Composition of input and output process stream shows some indication of polymerization and/or hydrogenation reaction of linoleic and linolenic acid, and also geometric isomerization of oleic acid. Thermodynamic feasibility of reaction was compared between high temperature and room temperature. In the near future, more energy-efficient and less-side reaction technology to produce fatty acids seems to compete with this conventional process.
Synthesis of Ceria Zirconia Oxides using Solvothermal Treatment
Authors: Machmudah Siti , Widiyastuti  , Winardi Sugeng , Wahyudiono  , Kanda Hideki , Goto Motonobu
Published: March 2018

Ceria oxide (CeO2) is widely used as catalyst with high oxygen storage capacity at low temperature. The addition of zirconia oxide (ZrO2) to CeO2 can enhance oxygen storage capacity as well as thermal stability. In this work, ceria zirconia oxides has been synthesized via a low temperature solvothermal treatment in order to produce ceria zirconia oxides composite with high oxygen storage capacity as electrolyte of solid oxide fuel cells (SOFC). Under solvothermal conditions, solvent may control the direction of crystal growth, morphology, particle size and size distribution, because of the controllability of thermodynamics and transport properties by pressure and temperature. Water, mixed of water and ethanol (70/30 vol/vol), and mixed of water and ethylene glycol (70/30 vol/vol) were used as solvent, while Ce(NO3)3 and ZrO(NO3)2 with 0.06 M concentration were used as precursor. The experiments were conducted at temperature of 150 °C and pressure for 2 h in a Teflon-lined autoclave of 100 mL volume. The synthesized products were dried at 60 °C for 6 and 12 h and then calcined at 900 °C for 6 h. The particle products were characterized using SEM, XRD, TG/DTA, and Potentiostat. The results showed that the morphology of particles formed were affected by the solvent. Solid plate shaped particles were produced in water, and tend to be pore with the addition of ethylene glycol. The addition of ethanol decreased the size of particles with sphere shaped. The XRD pattern indicated that ceria-zirconia oxides particles are uniformly distributed in the structure to form a homogeneous solid solution. Based on the electrochemical analysis, ceria zirconia oxides produced via solvothermal synthesis had high conductivity ion of 0.5594 S/cm, which is higher than minimum conductivity ion requirement of 0.01 S/cm for SOFC electrolyte. It indicated that ceria zirconia oxides produced via solvothermal synthesis is suitable for SOFC electrolyte.
Synthesis of a one-part geopolymer system for soil stabilizer using fly ash and volcanic ash
Authors: Tigue April Anne S. , Dungca Jonathan R. , Hinode Hirofumi , Kurniawan Winarto , Promentilla Michael Angelo B.
Published: March 2018

A novel approach one-part geopolymer was employed to investigate the feasibility of enhancing the strength of in-situ soil for possible structural fill application in the construction industry. Geopolymer precursors such as fly ash and volcanic ash were utilized in this study for soil stabilization. The traditional geopolymer synthesis uses soluble alkali activators unlike in the case of ordinary Portland cement where only water is added to start the hydration process. This kind of synthesis is an impediment to geopolymer soil stabilizer commercial viability. Hence, solid alkali activators such as sodium silicate (SS), sodium hydroxide (SH), and sodium aluminate (SA) were explored. The influence of amount of fly ash (15% and 25%), addition of volcanic ash (0% and 12.5%), and ratio of alkali activator SS:SH:SA (50:50:0, 33:33:33, 50:20:30) were investigated. Samples cured for 28 days were tested for unconfined compressive strength (UCS). To evaluate the durability, sample yielding highest UCS was subjected to sulfuric acid resistance test for 28 days. Analytical techniques such as X-ray fluorescence (XRF), X-ray diffraction (XRD), and scanning electron microscope/energy-dispersive X-ray spectroscopy (SEM/EDX) were performed to examine the elemental composition, mineralogical properties, and microstructure of the precursors and the geopolymer stabilized soil.
Development of Abaca Fiber-reinforced Foamed Fly Ash Geopolymer
Authors: Janne Pauline S. Ngo , Michael Angelo B. Promentilla
Published: March 2018

The growing environmental and economic concerns have led to the need for more sustainable construction materials. The development of foamed geopolymer combines the benefit of reduced environmental footprint and attractive properties of geopolymer technology with foam concrete’s advantages of being lightweight, insulating and energy-saving. In this study, alkali-treated abaca fiber-reinforced geopolymer composites foamed with H2O2were developed using fly ash as the geopolymer precursor. The effects of abaca fiber loading, foaming agent dosage, and curing temperature on mechanical strength were evaluated using Box-Behken design of experiment with three points replicated. Volumetric weight of samples ranged from 1966 kg/m3to 2249 kg/m3. Measured compressive strength and flexural ranged from 19.56 MPa to 36.84 MPa, and 2.41 MPa to 6.25 MPa, respectively. Results suggest enhancement of compressive strength by abaca reinforcement and elevated temperature curing. Results, however, indicate a strong interaction between curing temperature and foaming agent dosage, which observably caused the composite’s compressive strength to decline when simultaneously set at high levels. Foaming agent dosage was the only factor detected to significantly affect flexural strength.
Experimental Study of Paddy Grain Drying in Continuous Recirculation System Pneumatic Conveyor
Authors: Prasetyo Totok , Riska Listiyana , Arlanta Rahim , Sumardiono Siswo
Published: March 2018

Nowadays, paddy drying using conventional method is irrelevant to used. The increasing need of grain each year is one of the main factor that pushes scientist to invent new methods of drying paddy grain. The old method is unusefull since it takes up space, needed the sun as the drying media which causes a long drying time. One of the alternative of drying paddy grain is by using mechanic dryer. By using this dryer type, the process of drying takes faster comparing to the old method and the distribution of grain is supplied continuously. The dryer which uses pneumatic conveyor can be one of the solution due to its less energy consumption, a better drying result, and high drying capacity. The variable used to identify drying performance is temperature and loading weight. From the experiment, it is resulted that the best temperature for drying paddy grain is 60°C with the weight loading of 150 gram.
Diethyl Ether Production as a Substitute for Gasoline
Authors: Alviany Riza , Wahyudi Arifuddin , Gunardi Ignatius , Roesyadi Achmad , Kurniawansyah Firman , Hari Prajitno Danawati
Published: March 2018

Diethyl ether is one of alternative fuel that could be used as a significant component of a blend or as a complete replacement for transportation fuel. The aim of this research is to produce diethyl ether through dehydration reaction of ethanol with fixed bed reactor using nanocrystalline γ-Al2O3 catalyst. Nanocrystalline γ-Al2O3 catalyst was synthesized by precipitation method using Al(NO3)3.9H2O as precursors and NH4OH as the precipitating agent. Dehydration reaction was performed at temperature range of 125 to 225°C. The result shows that synthesized γ-Al2O3 catalyst gave higher ethanol conversion and diethyl ether yield than that of commercial Al2O3 catalyst. The use of synthesized γ-Al2O3 catalyst could reach ethanol conversion as high as 94.71% and diethyl ether yield as high as 11,29%.
Synthesis of Mercapto Ethyl Ester of Palm Fatty Acid Distillate
Authors: Putrawan I Dewa Gede Arsa , Azharuddin Adli , Arum Kartini Ratna , Adityawarman Dendy , Rahim Dicka Ar
Published: March 2018

This research is aimed to study the synthesis of mercapto ethyl ester of fatty acid (MEFA) using palm fatty acid distillate (PFAD). The synthesis was carried out in a jacketed stirred vessel. Water as a byproduct was removed by using vacuum evaporation. p-Toluene sulfonic acid was used as catalyst. Temperature, mercaptoethanol excess, and catalyst amount were varied during the experiments. The variations ranges were 60-80°C, 5-25 %-mole, and 0.8-3.2 %-mole, respectively. The accomplishment of reaction was evaluated by measuring the mercaptan content and yield of MEFA. The mercaptan content and yield of MEFA were in the ranges of 6.4-8.0% and 64-86%, respectively. It was found that mercaptan content and yield increased with temperature. The optimum temperature was found to be 70°C, considering the mercaptan content, yield, and appearance of the product obtained. A full 22 factorial design at a reaction temperature of 70°C showed that mercaptoethanol excess and catalyst amount had significant effects on the mercaptan content and yield of MEFA.
Cleaning Schedule Operations in Heat Exchanger Networks
Authors: Huda Hairul , Handogo Renanto , Biyanto Totok Ruki
Published: March 2018

Heat exchanger networks have been known to be the essential parts in the chemical industries. Unfortunately, since the performance of heat exchanger can be decreasing in transferring the heat from hot stream into cold stream due to fouling, then cleaning the heat exchanger is needed to restore its initial performance periodically. A process of heating crude oil in a refinery plant was used as a case study. As many as eleven heat exchangers were used to heat crude oil before it was heated by a furnace to the temperature required to the crude unit distillation column. The purpose of this study is to determine the cleaning schedule of heat exchanger on the heat exchanger networks due to the decrease of the overall heat transfer coefficient by various percentage of the design value. A close study on the process of heat exchanger cleaning schedule in heat exchanger networks using the method of decreasing overall heat transfer coefficient as target. The result showed that the higher the fouling value the more often the heat exchanger is cleaned because the overall heat transfer coefficient decreases quickly.
Desalination of Sea Water Using Polymer Inclusion Membran (PIM) With Aliquat 336-TBP (Tributhyl Phosphate) as Carrier Compound
Authors: Cholid Djunaidi Muhammad , Fauzi Henry , Hastuti Rum
Published: March 2018

Desalination of Sea Water using Polymer Inclusion Membrane has been done. PIM is known has high stability membrane to overcome the instability of liquid membrane. PIM was placed among two phase : source phases was sea water and feed phases was aquadest. Efficiency of desalination is known by determining salinity concentration and ion Na+ in feed phases and stripping phases using refractometer and AAS. while membrane characterization is done using FTIR. SEM and UV-Vis spectroscopy. The PIM membrane that is produced has thin. transparent. clear and flexible properties. The result showed that PIM transport for 24 hours give the highest of salinity transport. there are 92.68% is transported from feed phases and 84.87% in stripping phases. Membrane characterization result by FTIR and UV spectroscopy showed that PIM membrane is stable enough.
Synthesis and Characterization of Nano Hybrid Membrane PES-TiO2for Biogas Purification: Combination Effect of Ultra Violet and Cross-Linking
Authors: Kusworo Tutuk Djoko , Qudratun Budiyono , Utomo Dani Puji , Ramadhan Iqbal Ryan , Indriyanti
Published: March 2018

One of the alternative energy offered and can be used as a substitute for fossil energy is renewable energy. Examples of renewable energy are very abundant and can be developed in Indonesia is biogas. Biogas mostly contain CH4and CO2. Membrane separation is one of the most suitable process to make biogas more pure. So, it must be advanced to improve the membrane performance. The objectives of the current research are to investigate the effect of combined UV irradiation and cross linking on nano hybrid membrane PES-TiO2on their performance to separate CO2that contain in biogas. The nano hybrid membrane PES-TiO2was fabricated by preparing the dope solution containing PES, NMP as solvent, and nano TiO2. The membrane was casted by using NIPS method, with expose under UV lights for 1, 2, 3 min and followed by immersion in acetone-ethanol mixture for 24 hours. UV irradiation and cross linking treatments increased the selectivity and permeability of nano hybrid membrane PES-TiO2on CO2/CH4gas separation. The effect either UV irradiation or cross linking addition, make the void larger than before, so the selectivity and permeability can increase. With the addition of cross linking ethanol-acetone solution can reduce agglomeration in the membrane. The combination of UV irradiation and cross linking treatments can increase significantly in nano hybrid membrane PES-TiO2performance for CO2/CH4gas separation.
The welded CNC machine tool frame
Authors: Boral Piotr , Nieszporek Tadeusz , Gołębski Rafał
Published: March 2018

Machine tools are built based on cast-iron bodies. Cast iron well dumps down vibrations and is dimensionally stable. Therefore, many conventional machine tools are modernized and modified into CNC machine tools based on the seasoned old bodies of those machine tools. Nevertheless, CNC machine tools are also manufactured based on polymer concrete, which vibration damping ability is even better. On the other hand, attempts made in the past by leading machine tool manufacturers to use welded frames in CNC machine tools failed. The revival of interest in welded frames was spurred by economic considerations, as steel systems are much thinner compared to cast-iron ones. They are able to carry the same loads. The construction of CNC machine tools with a welded steel frame undertaken at the Institute of Mechanical Technologies (ITM) of the Czestochowa University of Technology is an attempt to solve this constructional problem. The machine tool frame was designed with use of CAD solid works system. The ultimate success of using the welded frame is determined not only by the frame itself, but also generally the design of the machine tool and its operation parameters. The welded frame was used for a high-accuracy three-axis milling machine. In this respect, it is equal of professional machine tools manufactured by reputed companies. It can be either a production machine tool or a test stand.
Analysis of residual stress in subsurface layers after precision hard machining of forging tools
Authors: Czan Andrej , Holubjak Jozef , Daniš Igor , Martinček Juraj , Mikloš Matej , Čep Robert , Hatala Michal , Malotova Šarka
Published: March 2018

This paper is focused on analysis of residual stress of functional surfaces and subsurface layers created by precision technologies of hard machining for progressive constructional materials of forging tools. Methods of experiments are oriented on monitoring of residual stress in surface which is created by hard turning (roughing and finishing operations). Subsequently these surfaces were etched in thin layers by electro-chemical polishing. The residual stress was monitored in each etched layer. The measuring was executed by portable X-ray diffractometer for detection of residual stress and structural phases. The results significantly indicate rise and distribution of residual stress in surface and subsurface layers and their impact on functional properties of surface integrity.
The application of the optical system ATOS II for rapid prototyping methods of non-classical models of cogbelt pulleys
Authors: Krawiec Piotr , Domek Grzegorz , Warguła Łukasz , Waluś Konrad , Adamiec Jarosław
Published: March 2018

The widespread application of both gear wheels and cogbelt pulleys with noncircular generating line in technique stimulates the development of manufacturing and measuring methods of these wheels. The paper presents the rapid prototyping methods of models of cogbelt pulleys with nocircular evelope. Evaluation method of manufacturing accuracy of cogbelt pulleys, which are applied in unevenrunning belt transmissions, are presented. These transmissions are widely applied in steering techniques and drives of machines and devices. Verification of mapping accuracy of shape of geometrical model of cogbelt pulley was done with the application of noncontact optical system i.e. coordinate optical scanner GOM Atos Compact Scan 5M GOM company.
Analysis of the influence of the cutting edge geometry on parameters of the perforation process for conveyor and transmission belts
Authors: Wojtkowiak Dominik , Talaśka Krzysztof , Malujda Ireneusz , Domek Grzegorz
Published: March 2018

Perforated belts, which are used in vacuum conveyor belts, can have significantly different mechanical properties like strength and elasticity due to a variety of used materials and can have different thickness from very thin (0,7 mm) to thick belts (6 mm). In order to design a complex machine for mechanical perforation, which can perforate whole range of belts, it is necessary to research the influence of the cutting edge geometry on the parameters of the perforation process. Three most important parameters, which describe the perforation process are the cutting force, the velocity and the temperature of the piercing punch. The results presented in this paper consider two different types of punching (a piercing punch with the punching die or with the reducer plate) and different cutting edge directions, angles, diameters and material properties. Test were made for different groups of composites belts – with polyurethane and polyester fabric, polyamide core or aramid-fibre reinforced polymers. The main goal of this research is to specify effective tools and parameters of the perforation process for each group of composites belts.
Sensitivity analysis overlaps of friction elements in cartridge seals
Authors: Žmindák Milan , Falat Miloš
Published: March 2018

Cartridge seals are self-contained units consisting of a shaft sleeve, seals, and gland plate. The applications of mechanical seals are numerous. The most common example of application is in bearing production for automobile industry. This paper deals with the sensitivity analysis of overlaps friction elements in cartridge seal and their influence on the friction torque sealing and compressive force. Furthermore, it describes materials for the manufacture of sealings, approaches usually used to solution of hyperelastic materials by FEM and short introduction into the topic wheel bearings. The practical part contains one of the approach for measurement friction torque, which results were used to specifying the methodology and precision of FEM calculation realized by software ANSYS WORKBENCH. This part also contains the sensitivity analysis of overlaps friction elements.
Investigation of kinematic parameters of two nonconventional piston machines with wobble board
Authors: Baran Peter , Šťastniak Pavol , Kukuča Pavol , Brezáni Miloš
Published: March 2018

Article deals with description of non-conventional mechanism FIK and mechanism with ring, which may be suitable for special applications in the engineering industry. It is possible to use not only classical crank mechanisms, but also non-conventional mechanisms in design of piston machines. Investigation of kinematic parameters of the machines is important step to know its basic movement behaviour, and from this, it is then possible to create the alternate dynamic model or force analysis. For kinematic comparison will be designed the same basic geometric conditions in both types of models. In terms of comparisons will be monitored mainly points on wobble board and the main part will be determination of piston stroke.
Numerical simulations of progressive hardening by using ABAQUS FEA software
Authors: Domański Tomasz , Piekarska Wiesława , Kubiak Marcin , Saternus Zbigniew , Goszczyńska-Króliszewska Dorota
Published: March 2018

The paper concerns numerical simulations of progressive hardening include phase transformations in solid state of steel. Abaqus FEA software is used for numerical analysis of temperature field and phase transformations. Numerical subroutines, written in fortran programming language are used in computer simulations where models of the distribution of movable heat source, kinetics of phase transformations in solid state as well as thermal and structural strain are implemented. Model for evaluation of fractions of phases and their kinetics is based on continuous heating diagram and continuous cooling diagram. The numerical analysis of thermal fields, phase fractions and strain associated progressive hardening of elements made of steel were done.
Engineering calculations for complex geometric domains
Authors: Gawronska Elzbieta , Dyja Robert , Grosser Andrzej , Winczek Jerzy
Published: March 2018

The paper aims to present the possibility of performing engineering calculations in domains of complex shapes expressed by mathematical descriptions. We focus on calculations done with the use of the Finite Element Method. An example of the compound structure is gyroid, which is a periodic structure representing an area close to the porous structure. The presented gyroid structure exhibits circular struts and a spherical core and spatially occupies a cube. The side length of the cube is defined as unit cell size, and the volume percentage of the struts inside the cube is referred to as volume fraction. The periodic cellular lattice structures are generated by our own software module. One of the uses of such structures is their employment in additive manufacturing (AM) of the so-called 3D printing (layer-by-layer AM technique), where they can contribute reducing the weight of an item and limiting the material consumption. It is important to answer the question of what effect does an element with a gyroid structure have on the thermal properties (e.g. the heat flow versus the volume fraction) compared to an element with full structure. The paper will show the results of such a comparison.
Noise and temperature reduction in the contact of tribological elements during braking
Authors: Gerlici Juraj , Gorbunov Mykola , Kravchenko Kateryna , Prosvirova Olga , Lack Tomas
Published: March 2018

This paper describes the problem of rising temperature of the friction elements during braking. Negative influence of brake pads heating on the vehicle efficiency and traffic safety is well known. Methods of temperature stabilization in the contact of tribological elements during braking are proposed. Variants of brake pad application with additional elements consisting of phase transition material are considered. Their effectiveness is estimated. The effect of the contact characteristics on noise generation is analysed. The method of noise reduction is considered. The target function for the tribological processes management in the contact of the brake elements has been developed. The application of this target function allows using the braking reserve with the achievement of maximum braking effect with minimal wear and noise.
Design of a device to simulate environmental influences on the course of brake tests
Authors: Harušinec Jozef , Suchánek Andrej , Loulová Mária , Strážovec Peter
Published: March 2018

When performing the technical tests of the brake system under laboratory conditions, it is necessary to create the same conditions as those in operation. The friction coefficient is dependent on a number of parameters, including airflow during ride and weather conditions. Therefore, during the take-over tests, both these conditions are obligatory to simulate. This paper describes the design of the chamber, which will allow the test stand RAILBCOT to carry out the so-called dry and wet tests with airflow as during real-life ride. It also isolates the acoustic emission and emission of braking material to the surrounding area when tested.
Numerical modal analysis for vibration-damping properties of ductile cast
Authors: Kováčiková Petra , Vavro Ján , Vavro Ján , Dubec Andrej
Published: March 2018

This paper deals with standard test method for the measurement of vibration-damping properties of materials, ductile cast iron - graphitic cast iron with the spherical shape of graphite (ductile cast iron). Investigation is focused on its mechanical properties, chemical composition and microstructure, which are necessary as input parameters for computational modeling and numerical analysis. The vibration or oscillating of experimental samples are closely connected with such parameters as natural shapes (eigenshapes) and natural frequencies (eigenfrequencies). Preparation of a geometric model of a homogeneous beam sample and numerical analysis was performed by finite element method in the ADINA software environment. This paper can be used for further development and growth from the aspect of application of computational tools in the area of damping and eigenfrequency properties for construction materials.
Computer simulations of thermal phenomena in surface heating process using the real distribution of Yb:YAG laser power
Authors: Kubiak Marcin , Dekýš Vladimír , Domański Tomasz , Novák Pavol , Saternus Zbigniew
Published: March 2018

This work concerns mathematical and numerical modelling of temperature field during Yb:YAG laser heating of sheets made of S355 steel with the motion of liquid steel in the fusion zone taken into account. Laser power distribution and the caustics are determined on the basis of the geostatistical kriging method. Temperature field and melted material velocity field in the fusion zone are obtained from the numerical solution of continuum mechanics equations using projection method and finite volume method. Numerical algorithms are implemented into computer solver using ObjectPascal programming language. Computer simulations of Yb:YAG laser heating process are performed for different process parameters. Characteristic zones of experimentally obtained cross sections of heated elements are compared to numerically predicted fusion zone and heat affected zone.
Numerical modelling of heat flows in the upper blast furnace of the electric arc furnace
Authors: Lenhard Richard , Malcho Milan , Ďurčanský Peter , Kaduchová Katarina
Published: March 2018

Contributing shows one of the alternatives to use the waste heat from an electric furnace hat with subsequent use for the need for heating water preparation and central heating. In a contribution is presents a numerical model of heat flows from electric arc furnace designed for, into a cooled furnace from which waste heat is led to the central heating system. The model was developed implementing the finite volume method in ANSYS-Fluent program code.
Evaluation of the technical condition of medium-sized boilers
Authors: Lošák Pavel , Létal Tomáš , Buzík Jiří , Naď Martin
Published: March 2018

The recent trend in the steam and electricity production has been both to increase the efficiency of the facility and to keep tightening legislation concerning emission limits. The lifetime of energy equipment is greatly influenced by the operating temperature, pressure and operating characteristics. The new conditions lead the operator to more often changes of these parameters, which has negative influence to the facility in terms of service life. Precise knowledge of the facility being operated and the ability to predict the residual life of its key parts in time is therefore necessary. A new methodology for determining the residual life and evaluating problematic situations of medium size boilers was developed at Brno University of Technology. Its approaches and advantages will be presented in this paper. The methodology provides the user with approaches for the lifetime evaluation of an equipment as a whole, based on detailed knowledge of the equipment being investigated and the ongoing damage. Additionally, if the equipment is continuously evaluated, it is possible to extend the inspection interval or to achieve a significantly higher lifetime of the entire equipment, thereby reducing the economic cost. If defined criteria are met, the methodology also allows inclusion of FEM and CFD simulations for achieving higher relevance of the results.
Thermal load non-uniformity estimation for superheater tube bundle damage evaluation
Authors: Naď Martin , Jegla Zdeněk , Létal Tomáš , Lošák Pavel , Buzík Jiří
Published: March 2018

Industrial boiler damage is a common phenomenon encountered in boiler operation which usually lasts several decades. Since boiler shutdown may be required because of localized failures, it is crucial to predict the most vulnerable parts. If damage occurs, it is necessary to perform root cause analysis and devise corrective measures (repairs, design modifications, etc.). Boiler tube bundles, such as those in superheaters, preheaters and reheaters, are the most exposed and often the most damaged boiler parts. Both short-term and long-term overheating are common causes of tube failures. In these cases, the design temperatures are exceeded, which often results in decrease of remaining creep life. Advanced models for damage evaluation require temperature history, which is available only in rare cases when it has been measured and recorded for the whole service life. However, in most cases it is necessary to estimate the temperature history from available operation history data (inlet and outlet pressures and temperatures etc.). The task may be very challenging because of the combination of complex flow behaviour in the flue gas domain and heat transfer phenomena. This paper focuses on estimating thermal load non-uniformity on superheater tubes via Computational Fluid Dynamics (CFD) simulation of flue gas flow including heat transfer within the domain consisting of a furnace and a part of the first stage of the boiler.
Numerical estimation of temperature field in a laser welded butt joint made of dissimilar materials
Authors: Saternus Zbigniew , Piekarska Wiesława , Kubiak Marcin , Domański Tomasz , Goszczyńska-Króliszewska Dorota
Published: March 2018

The paper concerns numerical analysis of thermal phenomena occurring in the butt welding of two different materials by a laser beam welding. The temperature distribution for the welded butt-joint is obtained on the basis of numerical simulations performed in the ABAQUS program. Numerical analysis takes into account the thermophysical properties of welded plate made of two different materials. Temperature distribution in analysed joints is obtained on the basis of numerical simulation in Abaqus/Standard solver, which allowed the determination of the geometry of laser welded butt-joint.
The effect of restraints type on the generated stresses in gantry crane beam
Authors: Sowa Leszek , Piekarska Wiesława , Skrzypczak Tomasz , Kwiatoń Paweł
Published: March 2018

This paper includes an analysis of the mechanical phenomena in the gantry crane beam, because the cranes are currently one of the most common devices for the transporting loads. Designing modern mechanical structures is a complex task that requires the use of appropriate tools. Such a modern tool is the numerical simulation, which uses different numerical methods. One of the best known methods is the finite element method, also used here. Simulations are limited to analysis of the strength of the gantry crane beam that was the loaded of the force load movement along its length. The numerical analysis was made to the gantry crane beam which cross-section was an I-beam and ends were fixed in different ways. As the result of numerical calculations, the stresses and displacements of the structure of gantry were obtained. The influence of the restraints type and changing the loading force position on generate the Huber-Misses stress in the gantry crane beam was estimated. The aim was to ensure that the maximum equivalent stress generated in the gantry crane beam was less than the strength of material, because then the construction is safe.
Analysis of the distribution of temperature fields in the braked railway wheel
Authors: Suchánek Andrej , Harušinec Jozef , Loulová Mária , Strážovec Peter
Published: March 2018

The article deals with detection of reduced stress in a braked railway wheel, based on thermal transient analysis on virtual models, which influence the characteristics of the railway wheels. Structural analysis was performed by means of the ANSYS Multiphysics program system package. Thermal transient analysis deals with detection of temperature fields which are a result of braking by brake block. The applied heat flux represents the heat generated by friction of brake block. It is applied to a quarter model of the wheel to speed up the calculation. This analysis simulates two braking processes with subsequent cooling. Distribution of the equivalent stress was detected in the railway wheel cross section, at selected points. The input parameters were taken from the thermal transient analysis. These equivalent stresses result from thermal load.
Modelling mechanical properties of the multilayer composite materials with the polyamide core
Authors: Talaśka Krzysztof , Wojtkowiak Dominik
Published: March 2018

Due to the wide range of application for belt conveyors, engineers look for many different combinations of mechanical properties of conveyor and transmission belts. It can be made by creating multilayer or fibre reinforced composite materials from base thermoplastic or thermosetting polymers. In order to gain high strength with proper elasticity and friction coefficient, the core of the composite conveyor belt is made of polyamide film core, which can be combined with various types of polymer fabrics, films or even rubbers. In this paper authors show the complex model of multilayer composite belt with the polyamide core, which can be used in simulation analyses. The following model was derived based on the experimental research, which consisted of tensile, compression and shearing tests. In order to achieve the most accurate model, proper simulations in ABAQUS were made and then the results were compared with empirical mechanical characteristics of a conveyor belt. The main goal of this research is to fully describe the perforation process of conveyor and transmission belts for vacuum belt conveyors. The following model will help to develop design briefs for machines used for mechanical perforation.
Calculated estimation of railway wheels equivalent conicity influence on critical speed of railway passenger car
Authors: Gerlici Juraj , Domin Rostyslav , Cherniak Ganna , Lack Tomáš
Published: March 2018

The article presents the results of determining the equivalent conicity characterizing the geometric interaction of wheels and rails on 1520 mm track. The cases of interactions of rails and wheelsets, wheels of which have different profiles, are considered. The computer model of the motion speed of the passenger car is developed. According to the results of computer simulation, critical speeds for the bogie moving through the tracks of indented gauge are received. Based on the results of the simulation analysis, the significant dependence of the value of the equivalent conicity on the critical speed is confirmed. The necessity of considering the limit values of equivalent conicity in tests of high-speed rolling stock is emphasized.