Chemical Industry最新文献

{"title":"Surface modification method of duplex type stainless steels by the pack boriding process","authors":"R. Hariharan, Balasundaram Rathinam, Baskar Neelakandan, R. Beemaraj, C. Kannan","doi":"10.2298/hemind210103019h","DOIUrl":"https://doi.org/10.2298/hemind210103019h","url":null,"abstract":"This work presents the investigation of a boriding process on two grades of stainless steel namely UNS32750 super duplex stainless steel and UNSS31803 duplex stainless steel in order to improve material properties and possibly to reduce catastrophic failure of industrial components. Usage of duplex stainless steels has become customary in the fields of oil and refinery, marine and pipeline applications due to increased corrosion resistance; however, these materials exhibit low wear characteristics. To overcome this problem, in this work the pack boriding process was employed. Evaluation of effects of the boriding process on the microstructure and mechanical properties was performed using scanning electron and optical microscopy, Vickers hardness tests and wear tests. It was shown that the 4 h process resulted in the greatest boriding layer thickness yielding the maximum surface hardness of 1407 HV in the super duplex stainless steel UNS32750 while this value was 1201 HV in the duplex stainless steel UNSS31803. Wear resistance of borided materials were up to 6-fold greater than those of non - treated materials. Also, the borided duplex materials were shown to be more suitable for industrial applications for valve and shaft components as compared to the boronized super duplex stainless steel.","PeriodicalId":9933,"journal":{"name":"Chemical Industry","volume":"26 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78681932","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Corrigendum in the article: Extraction of ammonium nickel sulfate hexahydrate by hydrometallurgical process from the hyperaccumulating plant Odontarrhena muralis - case study from Serbia","authors":"E. Editorial","doi":"10.2298/hemind211227033m","DOIUrl":"https://doi.org/10.2298/hemind211227033m","url":null,"abstract":"<jats:p>nema</jats:p>","PeriodicalId":9933,"journal":{"name":"Chemical Industry","volume":"116 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73407727","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Prediction of rubber vulcanization using an artificial neural network","authors":"Jelena Lubura, P. Kojić, J. Pavličević, Bojana Ikonić, R. Omorjan, O. Bera","doi":"10.2298/hemind210511026l","DOIUrl":"https://doi.org/10.2298/hemind210511026l","url":null,"abstract":"Determination of rubber rheological properties is indispensable in order to conduct efficient vulcanization process in rubber industry. The main goal of this study was development of an advanced artificial neural network (ANN) for quick and accurate vulcanization data prediction of commercially available rubber gum for tire production. The ANN was developed by using the platform for large-scale machine learning TensorFlow with the Sequential Keras-Dense layer model, in a Python framework. The ANN was trained and validated on previously determined experimental data of torque on time at five different temperatures, in the range from 140 to 180 oC, with a step of 10 oC. The activation functions, ReLU, Sigmoid and Softplus, were used to minimize error, where the ANN model with Softplus showed the most accurate predictions. Numbers of neurons and layers were varied, where the ANN with two layers and 20 neurons in each layer showed the most valid results. The proposed ANN was trained at temperatures of 140, 160 and 180 oC and used to predict the torque dependence on time for two test temperatures (150 and 170 oC). The obtained solutions were confirmed as accurate predictions, showing the mean absolute percentage error (MAPE) and mean squared error (MSE) values were less than 1.99 % and 0.032 dN2 m2, respectively.","PeriodicalId":9933,"journal":{"name":"Chemical Industry","volume":"25 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82989979","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Study of microstructure, hardness and thermal properties of Sn-Bi alloys","authors":"Kristina Božinović, D. Manasijević, Ljubiša Balanović, M. Gorgievski, Uroš Stamenković, Miljana S. Marković, Zoran Mladenovic","doi":"10.2298/hemind210119021b","DOIUrl":"https://doi.org/10.2298/hemind210119021b","url":null,"abstract":"Lead-free solders have become a main focus of the electronic industry in recent years, because of the high toxicity of lead. Alloys based on the Sn-Bi system figure as potential replacements for Sn-Pb alloys in soldering due to favorable properties and low cost. One of the main advantages of these alloys are low melting temperatures, while additional advantages include good compatibility with substrates, low process temperature, high reliability, and potential applications in conjunction with reduced graphene oxide nanosheets as thermal interface materials. In this paper, characterization of microstructural and thermal properties as well as hardness measurements of seven alloys of different Sn-Bi compositions are performed. Structural properties of the samples were analyzed using optical microscopy and scanning electron microscopy and energy dispersive X-ray spectroscopy (SEM-EDS). Thermal conductivity of the samples was investigated using the xenon-flash method, and phase transition temperatures were measured using the differential scanning calorimetry (DSC) analysis.","PeriodicalId":9933,"journal":{"name":"Chemical Industry","volume":"23 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75468618","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thermal conductivity analysis of Al2O3/water-ethylene glycol nanofluid by using factorial design of experiments in a natural convection heat transfer apparatus","authors":"P. Srinivasan, Nesakumar Dharmakkan, S. Vishnu, H. Prasath, Ramaraj Gogul","doi":"10.2298/hemind210520031s","DOIUrl":"https://doi.org/10.2298/hemind210520031s","url":null,"abstract":"Thermal conductivity of a heat transfer fluid plays a significant role in improving the heat transfer performance of a heat exchanger. In this work, experiments were performed in a natural convection heat transfer apparatus by mixing homogenized Al2O3 nanoparticles in a base fluid of water-ethylene glycol mixtures. The effects of heat input, nanoparticle volume content in the base fluid, and ethylene-glycol volume content in the base fluid on thermal conductivity of the nanofluid were analyzed. Based on results obtained by MINITAB? design software (factorial design matrix), 16 experimental runs were performed with the lower and higher levels of input factors. The levels for heat input were 10 and 100 W; for nanoparticle volume content in the base fluid 0.1 and 1 vol.% and for the base fluid composition 30 and 50 vol.% of ethylene glycol in water. From the obtained experimental results, a Pareto chart, normal probability plot, contour plot and surface plot were drawn. Based on the results, a new correlation was proposed, and predictions were compared with the experimental results. From the study, the maximum thermal conductivity value 0.49 W m-1 K-1 was observed at a nanoparticle volume content in the base fluid of 1.0 vol.%, ethylene glycol volume content in the base fluid of 30 vol.% and heat input of 100 W.","PeriodicalId":9933,"journal":{"name":"Chemical Industry","volume":"55 9 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80447011","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"New directions of biology and biotechnology in urban environmental sciences","authors":"E. A. Gladkov, O. Gladkova","doi":"10.2298/hemind211230034g","DOIUrl":"https://doi.org/10.2298/hemind211230034g","url":null,"abstract":"Living organisms and biological methods are widely used in recycling urban waste and improving the quality of the urban environment. Urban biology is a branch of biology that studies organisms living in cities. We propose using the new term \"urban biotechnology\". Urban biotechnology is the use of biotechnological methods to protect the urban environment and in urban energy. Urban biotechnology in the future may be included in the curriculum of the Master's degree programs \"Biotechnology\", \"Ecology \" (profile \"Applied Ecology\"), \"Chemistry\" (profile \" ?hemistry of the urban environment \"), and Chemical Engineering (profile \"Chemical and Biochemical Engineering \"). We consider it important to train specialists in the fields of urban biology and urban biotechnology. We hope that urban biotechnology and urban biology will become independent disciplines in the future.","PeriodicalId":9933,"journal":{"name":"Chemical Industry","volume":"223 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80025243","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"End view of the 71st Annual meeting of the International Society of Electrochemistry, Belgrade Online","authors":"J. Bajat, A. Dekanski","doi":"10.2298/hemind201015029b","DOIUrl":"https://doi.org/10.2298/hemind201015029b","url":null,"abstract":"<jats:p>nema</jats:p>","PeriodicalId":9933,"journal":{"name":"Chemical Industry","volume":"9 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89726983","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Production and characterization of liposomes with encapsulated bioactive soy protein hydrolysate","authors":"Neda Pavlović, J. Jovanovic, Verica B Djordjević, Bojana D. Balanč, B. Bugarski, Z. Knežević-Jugović","doi":"10.2298/hemind200530030p","DOIUrl":"https://doi.org/10.2298/hemind200530030p","url":null,"abstract":"Soy proteins known for their high nutritional value and pronounced techno-functional properties, can be hydrolyzed by using proteolytic enzymes and thus converted into hydrolysates rich in di-, tri- and oligopeptides. The resulting peptides are carriers of valuable biological activities, which make the soy hydrolysates very important in functional food applications as techno-functional and bioactive ingredients. However, commercial incorporation and application of soy protein hydrolysates can be hinderedby their low bioavailability and instability, bitter taste, hygroscopicity and possibility to interact with the food matrix. The aim of this research is encapsulation of the soy protein hydrolysate in liposomes in order to overcome the stated shortcomings, while preserving the biological activities that protein hydrolysates exhibit. The soy hydrolysate was prepared by a two-step enzymatic hydrolysis of a soy protein concentrate using commercial food-grade proteases, endoprotease from Bacillus amyloliquefaciens (Neutrase?) and egzo- and endoprotease from Aspergillus oryzae (Flavourzyme?) and encapsulated within liposomes. The liposomes were produced by a thin film method using a commercial lipid mixture (Phospolipon? 90G) containing mainly phosphatidylcholine. Next, the obtained multilamellar vesicles (MLV) with the soy protein hydrolysate were treated by high-intensity ultrasound waves generated by using (1) an ultrasonic probe at a frequency of 20 kHz and (2) an ultrasonic bath with a frequency 40 kHz. The smallest (310 nm) and uniform (unimodal size distribution) liposomes with the highest efficiency of peptide encapsulation (19 %) were obtained by the probe sonication. The presented results showed that incorporation of the soy protein hydrolysates was achieved within the liposome membrane and caused an increase in the liposome size in all tested formulations, namely: from 297 to 310 nm by using the ultrasonic probe, from 722 to 850 nm by using the ultrasonic bath, while in formulations without the ultrasonic treatments the increase from 2818 to 3464 nm was recorded. The entrapped peptides caused enlargement of all liposomes and the increase in negative charge of zeta potential values, which in the case of MLV liposomes was below -30 mV, indicating high stability of these liposomes. Significant antioxidant activity of the probe-sonicated liposomal formulation was confirmed by the ABTS scavenging ability and iron-chelating activity. Release studies conducted under simulated gastrointestinal conditions confirmed that liposomes provide prolonged release of encapsulated soy protein hydrolysates as compared to diffusion of the free hydrolysate. In the first 75 min, only 20 % of liposome encapsulated soy peptides diffused, which is 2.2-fold lower as compared to the diffusion of the non-encapsulated soy hydrolysate. Liposome encapsulated soy protein hydrolysates may provide the possibility for application in the areas such as food science and technolog","PeriodicalId":9933,"journal":{"name":"Chemical Industry","volume":"240 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78160823","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Incorporation of essential oils into pumpkin oil cake-based materials in order to improve their properties and reduce water sensitivity","authors":"S. Bulut, S. Popović, N. Hromiš, D. Šuput, D. Adamović, V. Lazić","doi":"10.2298/hemind2000026b","DOIUrl":"https://doi.org/10.2298/hemind2000026b","url":null,"abstract":"Biopolymer-based materials present good alternatives for synthetic materials. However, their high water sensitivity may limit their usage for food products packaging. Addition of hydrophobic components into the material formulation could improve this property. In this work 3, 4 and 5 % (v/v) of Satureja montana or Ocimum basilicum essential oil was incorporated into biopolymer films based on pumpkin oil cake. The obtained materials were analyzed regarding mechanical, physicochemical, barrier and structural properties. Incorporation of the essential oils increased the thickness of the pumpkin oil cake film. Significant reductions in moisture sensitivity, related to physicochemical properties and water vapor transmission rate (almost for 30 %), were observed (p < 0.05). Improvement of light barrier properties was also observed so that the visible light transmission was decreased for around 50 % while the UV light transmission was lower than 1 %. The obtained FTIR spectra confirmed the presence of added essential oils in pumpkin oil cake films, as well as their influence on the reduction in the film surface hydrophilicity. However, mechanical properties, tensile strength and elongation at break, decreased significantly (p < 0.05). These results suggest that incorporation of Satureja montana or Ocimum basilicum essential oil improved barrier properties of pumpkin oil cake-based films and reduced the film affinity toward water.","PeriodicalId":9933,"journal":{"name":"Chemical Industry","volume":"22 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75935594","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optimization of injected radiotracer volume for flow rate measurement in closed conduits","authors":"M. Pavlovic, Marijana Pantovic-Pavlovic, P. Bartl, J. Stevanovic, B. Radak","doi":"10.2298/HEMIND20050325P","DOIUrl":"https://doi.org/10.2298/HEMIND20050325P","url":null,"abstract":"In chemical processes it is essential that the flow in the process is accurately defined. Fluid velocity measurements are important for fluid flow quality performance in flow systems. This study focuses on determination of the volumetric flow rate and its standard (relative) deviation for calibration of conventional flow meters by using a radiotracer approach. The measurements for flow meter calibration were performed at a pilot-scale flow rig using Technetium-99 m (99mTc) as a radiotracer in the form of pertechnetate ion (99mTcO4-). The measured data were analyzed, and precision of the experimental setup was investigated under two different approaches ? IAEA?s RTD software and sum approximation of raw data. For the first time, the variation of standard deviation of calculated flow rate with the injection volume and activity of the radiotracer was determined. Plug flow with axial dispersion was used to simulate the measured RTD curves and investigate the flow dynamics of the flowing water. The results of the study have shown the possibility of in situ calibration of flow meters with a relative error lower than 1 %. They also revealed a slight dependency of the precision of output results on the injection volume as well as similar results for manual and specialized RTD software data processing.","PeriodicalId":9933,"journal":{"name":"Chemical Industry","volume":"53 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80407196","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}