Pub Date : 2023-06-30DOI: 10.17350/hjse19030000300
Cengiz Akkale
Bacillus subtilis has been a reliable platform for the expression of extracellular proteases for several decades. Although a majority of Bacillus subtilis subspecies express proteases, the amount of secreted enzyme varies depending on the strain and environmental conditions used. Here, two Bacillus subtilis spp. subtilis strains, NRRL B-3384 and NRRL B-3387, from the ARS Culture collection (NRRL), were compared for secreted protease activity. The highest activity was found in strain NRRL B-3384, and proteolysis occurred at temperatures as high as 80°C and across a broad range of pH, with maximum activity at pH 9.0 and 60°C indicating the presence of a thermostable alkaline protease. To our knowledge, this is the first study to evaluate protease production in Bacillus subtilis spp. subtilis strains NRRL B-3384 and B3387 and suggests that NRRL B-3384 may have utility in the production of enzymes for industrial use.
{"title":"Production, Optimization and Partial Characterization of Alkaline Protease from Bacillus subtilis spp. subtilis NRRL B-3384 and B-3387","authors":"Cengiz Akkale","doi":"10.17350/hjse19030000300","DOIUrl":"https://doi.org/10.17350/hjse19030000300","url":null,"abstract":"Bacillus subtilis has been a reliable platform for the expression of extracellular proteases for several decades. Although a majority of Bacillus subtilis subspecies express proteases, the amount of secreted enzyme varies depending on the strain and environmental conditions used. Here, two Bacillus subtilis spp. subtilis strains, NRRL B-3384 and NRRL B-3387, from the ARS Culture collection (NRRL), were compared for secreted protease activity. The highest activity was found in strain NRRL B-3384, and proteolysis occurred at temperatures as high as 80°C and across a broad range of pH, with maximum activity at pH 9.0 and 60°C indicating the presence of a thermostable alkaline protease. To our knowledge, this is the first study to evaluate protease production in Bacillus subtilis spp. subtilis strains NRRL B-3384 and B3387 and suggests that NRRL B-3384 may have utility in the production of enzymes for industrial use.","PeriodicalId":285705,"journal":{"name":"Hittite Journal of Science and Engineering","volume":"8 3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123629593","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}
Pub Date : 2023-06-30DOI: 10.17350/hjse19030000305
S. Sismanoglu
The degradation times of composite materials containing petroleum-based polymer matrix are quite long in nature and it causes environmental pollution. Researchers focus on producing alternative composite materials with organic and/or inorganic fillers to reduce degradation times in nature. In addition, the mechanical and chemical properties of polymer matrix composites are affected by heat, light, moisture and surface compatibility between matrix and filler. In the light of this information, many researchers examine the mechanical, thermal, morphological and similar properties of organic and/or inorganic filler composites by using artificial aging processes using one or more of the water, UV and temperature parameters. In this study, bentonite with surface modification by epoxysilane agent, and bentonite without any surface modification will be added to the thermoplastic polyurethane (TPU) polymer matrix, which has two different segments, and will be mixed in a twin screw extruder and it will then be shaped by the injection molding process. Artificial aging processes of the obtained composites will be done under UV and UV+water for 2 and 4 weeks, respectively. The reason for choosing UV and UV+water processes is that UV and water processes have not been applied together at the same time and there is not much knowledge in the literature on this subject. Mechanical, thermal and morphological properties of composites were investigated.
{"title":"UV and UV+ Water Effects on Mechanical, Thermal and Morphological Properties of Thermoplastic Polyurethane Based Composites","authors":"S. Sismanoglu","doi":"10.17350/hjse19030000305","DOIUrl":"https://doi.org/10.17350/hjse19030000305","url":null,"abstract":"The degradation times of composite materials containing petroleum-based polymer matrix are quite long in nature and it causes environmental pollution. Researchers focus on producing alternative composite materials with organic and/or inorganic fillers to reduce degradation times in nature. In addition, the mechanical and chemical properties of polymer matrix composites are affected by heat, light, moisture and surface compatibility between matrix and filler. In the light of this information, many researchers examine the mechanical, thermal, morphological and similar properties of organic and/or inorganic filler composites by using artificial aging processes using one or more of the water, UV and temperature parameters. \u0000In this study, bentonite with surface modification by epoxysilane agent, and bentonite without any surface modification will be added to the thermoplastic polyurethane (TPU) polymer matrix, which has two different segments, and will be mixed in a twin screw extruder and it will then be shaped by the injection molding process. Artificial aging processes of the obtained composites will be done under UV and UV+water for 2 and 4 weeks, respectively. The reason for choosing UV and UV+water processes is that UV and water processes have not been applied together at the same time and there is not much knowledge in the literature on this subject. Mechanical, thermal and morphological properties of composites were investigated.","PeriodicalId":285705,"journal":{"name":"Hittite Journal of Science and Engineering","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125053600","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}
Pub Date : 2023-03-31DOI: 10.17350/hjse19030000285
Pinar Mert Cuce, E. Cuce
In this study, the design, manufacture and thermal performance analysis of a Fresnel lens driven hot water/steam generator are presented. The designed system is suitable for domestic and industrial hot water/steam usage and can be easily scaled up to meet different capacity needs. In the first step of the research, thermal behaviour of the cast plate heat exchanger driven by a Fresnel lens with a concentration ratio of 100 is investigated at different working fluid velocities (0.6, 0.8, 1.0, 1.5 and 2.0 m/s) and at different absorber surface temperatures (700, 800, 900 and 1000 °C). Outlet temperature of working fluid from the cast plate heat exchanger is determined through a 3D CFD model for each case. The capacity of the steam generator for different operating times (h = 1, 2 and 3 hours) is also evaluated. The highest working fluid temperature at the outlet of heat exchanger is 914.8 °C for T_cp= 1000 °C and V_wf = 0.6 m/s. On the other hand, the lowest temperature is observed as 424.7 °C for T_cp = 700 °C and V_wf = 2.0 m/s. The steam capacity of the system for h = 3 hours is determined as 1696.5 and 508.9 kg in the best (V_wf = 2.0 m/s) and worst cases (V_wf = 0.6 m/s), respectively.
{"title":"Performance Analysis of Fresnel Lens Driven Hot Water/Steam Generator for Domestic and Industrial Use: A CFD Research","authors":"Pinar Mert Cuce, E. Cuce","doi":"10.17350/hjse19030000285","DOIUrl":"https://doi.org/10.17350/hjse19030000285","url":null,"abstract":"In this study, the design, manufacture and thermal performance analysis of a Fresnel lens driven hot water/steam generator are presented. The designed system is suitable for domestic and industrial hot water/steam usage and can be easily scaled up to meet different capacity needs. In the first step of the research, thermal behaviour of the cast plate heat exchanger driven by a Fresnel lens with a concentration ratio of 100 is investigated at different working fluid velocities (0.6, 0.8, 1.0, 1.5 and 2.0 m/s) and at different absorber surface temperatures (700, 800, 900 and 1000 °C). Outlet temperature of working fluid from the cast plate heat exchanger is determined through a 3D CFD model for each case. The capacity of the steam generator for different operating times (h = 1, 2 and 3 hours) is also evaluated. The highest working fluid temperature at the outlet of heat exchanger is 914.8 °C for T_cp= 1000 °C and V_wf = 0.6 m/s. On the other hand, the lowest temperature is observed as 424.7 °C for T_cp = 700 °C and V_wf = 2.0 m/s. The steam capacity of the system for h = 3 hours is determined as 1696.5 and 508.9 kg in the best (V_wf = 2.0 m/s) and worst cases (V_wf = 0.6 m/s), respectively.","PeriodicalId":285705,"journal":{"name":"Hittite Journal of Science and Engineering","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128324611","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}
Pub Date : 2023-03-13DOI: 10.17350/hjse19030000295
Fatma Pınar GÖRDESLİ DUATEPE
FliA is an important regulatory component for the synthesis of surface macromolecules which are involved in motility and biofilm development of Escherichia coli. In this study, the roles of FliA-dependent surface macromolecules in E. coli surface tension, surface heterogeneity and surface roughness, and initial biofilm development consisting of reversible and irreversible adhesion were investigated using E. coli MG1655 wild-type strain and fliA gene deleted mutant strain. Negative Gibbs free energy change values calculated using bacterial surface tensions obtained by a spectrophotometric method showed that both wild-type and mutant cells in water can reversibly adhere to the surface of the model solid, silicon nitride (Si3N4). The calculations further showed that bacterial reversible auto-adhesion and co-adhesion were also thermodynamically favorable. In comparison, the reversible adhesion and auto-adhesion capacities of wild-type cells were higher than the mutant cells. Direct measurements by atomic force microscopy (AFM) and thorough analysis of the recorded adhesion data showed that the irreversible adhesion strength of wild-type cells to Si3N4 in water was at least 2.0-fold greater than that of the mutants due to significantly higher surface heterogeneity resulting in higher surface roughness for the wild-type cells compared to those obtained for the mutants. These results suggest that strategies aimed at preventing E. coli biofilm development should also consider a combined method, such as modifying the surface of interest with a bacterial repellent layer and targeting the FliA and FliA-dependent surface macromolecules to reduce both reversible and irreversible bacterial adhesion and hence the initial biofilm development of E. coli.
{"title":"FliA-Dependent Surface Macromolecules Promote Initial Biofilm Development of Escherichia coli by Influencing the Bacterial Surface Properties","authors":"Fatma Pınar GÖRDESLİ DUATEPE","doi":"10.17350/hjse19030000295","DOIUrl":"https://doi.org/10.17350/hjse19030000295","url":null,"abstract":"FliA is an important regulatory component for the synthesis of surface macromolecules which are involved in motility and biofilm development of Escherichia coli. In this study, the roles of FliA-dependent surface macromolecules in E. coli surface tension, surface heterogeneity and surface roughness, and initial biofilm development consisting of reversible and irreversible adhesion were investigated using E. coli MG1655 wild-type strain and fliA gene deleted mutant strain. Negative Gibbs free energy change values calculated using bacterial surface tensions obtained by a spectrophotometric method showed that both wild-type and mutant cells in water can reversibly adhere to the surface of the model solid, silicon nitride (Si3N4). The calculations further showed that bacterial reversible auto-adhesion and co-adhesion were also thermodynamically favorable. In comparison, the reversible adhesion and auto-adhesion capacities of wild-type cells were higher than the mutant cells. Direct measurements by atomic force microscopy (AFM) and thorough analysis of the recorded adhesion data showed that the irreversible adhesion strength of wild-type cells to Si3N4 in water was at least 2.0-fold greater than that of the mutants due to significantly higher surface heterogeneity resulting in higher surface roughness for the wild-type cells compared to those obtained for the mutants. These results suggest that strategies aimed at preventing E. coli biofilm development should also consider a combined method, such as modifying the surface of interest with a bacterial repellent layer and targeting the FliA and FliA-dependent surface macromolecules to reduce both reversible and irreversible bacterial adhesion and hence the initial biofilm development of E. coli.","PeriodicalId":285705,"journal":{"name":"Hittite Journal of Science and Engineering","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128019445","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}
Pub Date : 2023-02-27DOI: 10.17350/hjse19030000292
Yusuf Kanca
CoNiAl based ferromagnetic shape memory alloys (FSMAs) are used in various engineering fields, but still need to be improved for tribological applications. In the present study, dry sliding wear behavior of CoNiAlSiSb and CoNiAlSiIn FSMAs was investigated as they were articulated against an alumina abrasive ball using a ball-on-disk tribometer. The experiments were carried out at a load of 20 N, a sliding velocity of 20 mm/s and a sliding distance of 250 m. The worn surfaces were assessed using scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDS). The mechanical properties of the CoNiAl based FSMAs were investigated using the nanoindentation technique. The results showed that as compared to CoNiAlSiSb, CoNiAlSiIn FSMA showed a 42% increase in the Young’s modulus and a 10% increase in the microhardness. The mean coefficient of friction (COF) of CoNiAlSiIn (0.56) was observed to be slightly lower than that of CoNiAlSiSb (0.58). The higher hardness and elastic modulus of CoNiAlSiIn than CoNiAlSiIn caused only a 7% increase in the wear resistance. The operative wear mechanisms were abrasion, adhesion and plastic deformation. In conclusion, even though the difference in the tribological performance of the two FSMA surfaces was fairly small, CoNiAlSiIn exhibited better results and thereby would be more preferable.
{"title":"Mechanical and wear properties of CoNiAlSiSb and CoNiAlSiIn ferromagnetic shape memory alloys: an experimental assessment","authors":"Yusuf Kanca","doi":"10.17350/hjse19030000292","DOIUrl":"https://doi.org/10.17350/hjse19030000292","url":null,"abstract":"CoNiAl based ferromagnetic shape memory alloys (FSMAs) are used in various engineering fields, but still need to be improved for tribological applications. In the present study, dry sliding wear behavior of CoNiAlSiSb and CoNiAlSiIn FSMAs was investigated as they were articulated against an alumina abrasive ball using a ball-on-disk tribometer. The experiments were carried out at a load of 20 N, a sliding velocity of 20 mm/s and a sliding distance of 250 m. The worn surfaces were assessed using scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDS). The mechanical properties of the CoNiAl based FSMAs were investigated using the nanoindentation technique. The results showed that as compared to CoNiAlSiSb, CoNiAlSiIn FSMA showed a 42% increase in the Young’s modulus and a 10% increase in the microhardness. The mean coefficient of friction (COF) of CoNiAlSiIn (0.56) was observed to be slightly lower than that of CoNiAlSiSb (0.58). The higher hardness and elastic modulus of CoNiAlSiIn than CoNiAlSiIn caused only a 7% increase in the wear resistance. The operative wear mechanisms were abrasion, adhesion and plastic deformation. In conclusion, even though the difference in the tribological performance of the two FSMA surfaces was fairly small, CoNiAlSiIn exhibited better results and thereby would be more preferable.","PeriodicalId":285705,"journal":{"name":"Hittite Journal of Science and Engineering","volume":"81 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134633684","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}
Pub Date : 2023-02-20DOI: 10.17350/hjse19030000288
M. Okutan, A. Asan, Hacer Ebru Si̇nger
Mild steel is primarily used in reinforced concrete structures, because it has a low corrosion rate due to the formation of a passive oxide film in the alkaline environment. However, when exposed to acidic and atmospheric environments or aqueous environments containing dissolved salts such as sea water, the protective film deteriorates and corrosion occurs due to contamination caused by chloride and carbonation. It is possible to obtain corrosion inhibitors by extraction of bioactive compounds from plants. Thus, inexpensive and environmentally friendly new effective inhibitors are obtained as an alternative to environmentally harmful inhibitors. In this context, the subject of the study was determined as the investigation of the inhibition efficiency of the vanillin phenolic compound in the Çorum Oğuzlar walnut shell extract, which is a local product, on the corrosion of AISI 1010 mild steel in acidic, alkaline and salty environments. The walnut shells, which were cleaned, ground and pre-sieved with a certain grain size, were extracted in seven different solvents. In order to find the appropriate solvent, the total phenolic content (TPC) in the extracts was determined by both the Folin Ciocalteu method and the liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) system. Cyclic voltammetry (CV) and Tafel polarization methods were applied to determine the effect of the extract on the electrochemical behavior of AISI 1010 and its corrosion rate. LC-MS/MS analysis showed the presence of compounds containing p electrons, N and O heteroatoms responsible for the corrosion inhibition. The best inhibition effectiveness was obtained with 86.1% acetone-water mixture in acidic environment (0.2 M HCl).
低碳钢主要用于钢筋混凝土结构，因为它在碱性环境中形成被动氧化膜，腐蚀速率低。然而，当暴露于酸性和大气环境或含有溶解盐的水环境(如海水)时，由于氯化物和碳酸化引起的污染，保护膜会恶化并发生腐蚀。通过从植物中提取生物活性化合物来获得缓蚀剂是可能的。因此，获得了廉价和环保的新型有效抑制剂，以替代对环境有害的抑制剂。在此背景下，本研究的主题被确定为考察当地产品Çorum Oğuzlar核桃壳提取物中香兰素酚类化合物对AISI 1010低碳钢在酸性、碱性和咸味环境中的腐蚀抑制效果。这些核桃壳经过清洗、研磨和预先筛选，具有一定的颗粒大小，用七种不同的溶剂提取。为了寻找合适的溶剂，采用Folin Ciocalteu法和液相色谱-质谱/质谱(LC-MS/MS)联用系统对提取物中总酚含量(TPC)进行测定。采用循环伏安法(CV)和Tafel极化法测定了提取物对AISI 1010电化学行为和腐蚀速率的影响。LC-MS/MS分析表明，含有p电子、N和O杂原子的化合物对腐蚀有抑制作用。在酸性环境(0.2 M HCl)中，以86.1%的丙酮-水混合液的抑菌效果最佳。
{"title":"The effect of the Oğuzlar walnut extract as a green corrosion inhibitor on AISI 1010 mild steel","authors":"M. Okutan, A. Asan, Hacer Ebru Si̇nger","doi":"10.17350/hjse19030000288","DOIUrl":"https://doi.org/10.17350/hjse19030000288","url":null,"abstract":"Mild steel is primarily used in reinforced concrete structures, because it has a low corrosion rate due to the formation of a passive oxide film in the alkaline environment. However, when exposed to acidic and atmospheric environments or aqueous environments containing dissolved salts such as sea water, the protective film deteriorates and corrosion occurs due to contamination caused by chloride and carbonation. It is possible to obtain corrosion inhibitors by extraction of bioactive compounds from plants. Thus, inexpensive and environmentally friendly new effective inhibitors are obtained as an alternative to environmentally harmful inhibitors. In this context, the subject of the study was determined as the investigation of the inhibition efficiency of the vanillin phenolic compound in the Çorum Oğuzlar walnut shell extract, which is a local product, on the corrosion of AISI 1010 mild steel in acidic, alkaline and salty environments. The walnut shells, which were cleaned, ground and pre-sieved with a certain grain size, were extracted in seven different solvents. In order to find the appropriate solvent, the total phenolic content (TPC) in the extracts was determined by both the Folin Ciocalteu method and the liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) system. Cyclic voltammetry (CV) and Tafel polarization methods were applied to determine the effect of the extract on the electrochemical behavior of AISI 1010 and its corrosion rate. LC-MS/MS analysis showed the presence of compounds containing p electrons, N and O heteroatoms responsible for the corrosion inhibition. The best inhibition effectiveness was obtained with 86.1% acetone-water mixture in acidic environment (0.2 M HCl).","PeriodicalId":285705,"journal":{"name":"Hittite Journal of Science and Engineering","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126904025","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}
Pub Date : 2023-02-18DOI: 10.17350/hjse19030000290
Esra Ölmez, Ebru Gökmeşe, Ü. Ergun, Faruk Gokmese
Food security is a priority issue for sustainable global development. In rapid industrialization areas with high fallout of airborne particles, metal uptake by plants could strongly impact crop quality. In this study, concentrations of some heavy metals (Cu, Zn, and Pb) in flour samples supplied in Çorum, defined as one of the “New Industry Focus”, were investigated using inductively coupled plasma-optical emission spectrometry (ICP-OES) to determine the heavy metal contamination. The results showed that the concentration of Pb in all samples examined exceeded the maximum permissible limit. To monitor the increase in Pb concentration and its relationship with air pollution, a two-year laboratory experiment was conducted. It was found that the increase in Pb concentration of about 47% and 77% for two flour samples was consistent with the increase in annual average PM10 concentrations (55% and 82%) obtained from two stations.
{"title":"Determination of Some Heavy Metals in Wheat Flour of Çorum Province, Turkey: An Air Quality Comparison","authors":"Esra Ölmez, Ebru Gökmeşe, Ü. Ergun, Faruk Gokmese","doi":"10.17350/hjse19030000290","DOIUrl":"https://doi.org/10.17350/hjse19030000290","url":null,"abstract":"Food security is a priority issue for sustainable global development. In rapid industrialization areas with high fallout of airborne particles, metal uptake by plants could strongly impact crop quality. In this study, concentrations of some heavy metals (Cu, Zn, and Pb) in flour samples supplied in Çorum, defined as one of the “New Industry Focus”, were investigated using inductively coupled plasma-optical emission spectrometry (ICP-OES) to determine the heavy metal contamination. The results showed that the concentration of Pb in all samples examined exceeded the maximum permissible limit. To monitor the increase in Pb concentration and its relationship with air pollution, a two-year laboratory experiment was conducted. It was found that the increase in Pb concentration of about 47% and 77% for two flour samples was consistent with the increase in annual average PM10 concentrations (55% and 82%) obtained from two stations.","PeriodicalId":285705,"journal":{"name":"Hittite Journal of Science and Engineering","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130333147","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}
Pub Date : 2023-02-16DOI: 10.17350/hjse19030000293
Ümit Işkan, M. Kahraman, M. Di̇rek
This study aims experimentally to investigate the performance analysis of R134a and alternative R516A refrigerant in two evaporator ejector cooling system (DEES) at different air velocities of evaporator#1. Firstly, the tests were carried out with R134a refrigerant under steady-state conditions at different air velocities and then repeated with low GWP R516A refrigerant. As the tests were carried out with R134a, higher cooling capacity was achieved at different air velocity values. When the air velocity value was 1.1, 1.7, 2.2, and 2.7 ms-1, the COP value obtained from the tests with R134a was 1%, 2%, 5%, and 4% higher than R516A, respectively. Additionally, test results illustrate that the higher air velocity contributed to increasing performance parameters however higher air velocity than 2.2 ms-1 had a slight effect. Based on this study, it is concluded that R516A performance is convenient to R134a performance and can be alternatively used as a refrigerant in vapor compression refrigeration systems(BSS).
{"title":"Comparison of R134a and R516A’s performance at Different Air Velocities in Two Evaporator Ejector Cooling System","authors":"Ümit Işkan, M. Kahraman, M. Di̇rek","doi":"10.17350/hjse19030000293","DOIUrl":"https://doi.org/10.17350/hjse19030000293","url":null,"abstract":"This study aims experimentally to investigate the performance analysis of R134a and alternative R516A refrigerant in two evaporator ejector cooling system (DEES) at different air velocities of evaporator#1. Firstly, the tests were carried out with R134a refrigerant under steady-state conditions at different air velocities and then repeated with low GWP R516A refrigerant. As the tests were carried out with R134a, higher cooling capacity was achieved at different air velocity values. When the air velocity value was 1.1, 1.7, 2.2, and 2.7 ms-1, the COP value obtained from the tests with R134a was 1%, 2%, 5%, and 4% higher than R516A, respectively. Additionally, test results illustrate that the higher air velocity contributed to increasing performance parameters however higher air velocity than 2.2 ms-1 had a slight effect. Based on this study, it is concluded that R516A performance is convenient to R134a performance and can be alternatively used as a refrigerant in vapor compression refrigeration systems(BSS).","PeriodicalId":285705,"journal":{"name":"Hittite Journal of Science and Engineering","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134224598","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}
Pub Date : 2023-02-13DOI: 10.17350/hjse19030000291
Zeycan Helvaci
This research focuses on species distribution modelling (SDM) to have an idea of distribution of Anatolian spiny mouse, Acomys cilicicus in the Last Glacial Maximum (LGM), the mid-Holocene and present by using coordinates along Silifke which is the only location the species found. Three ensembled species distribution models (generalized additive models, maximum entropy and boosted regression trees) were used to project Anatolian spiny mouse environmental suitability. Results indicate that current distribution of A. cilicicus populations shifted east to west since during the Last Glacial Maximum and apparently eastern part of the Mediterranean region of Turkey is potential refugia for this species.
{"title":"Influence of past climate changes on the current distribution of a rare and endemic species: Anatolian spiny mouse","authors":"Zeycan Helvaci","doi":"10.17350/hjse19030000291","DOIUrl":"https://doi.org/10.17350/hjse19030000291","url":null,"abstract":"This research focuses on species distribution modelling (SDM) to have an idea of distribution of Anatolian spiny mouse, Acomys cilicicus in the Last Glacial Maximum (LGM), the mid-Holocene and present by using coordinates along Silifke which is the only location the species found. Three ensembled species distribution models (generalized additive models, maximum entropy and boosted regression trees) were used to project Anatolian spiny mouse environmental suitability. Results indicate that current distribution of A. cilicicus populations shifted east to west since during the Last Glacial Maximum and apparently eastern part of the Mediterranean region of Turkey is potential refugia for this species.","PeriodicalId":285705,"journal":{"name":"Hittite Journal of Science and Engineering","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115277455","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}
Pub Date : 2023-02-13DOI: 10.17350/hjse19030000294
A. A. Topcu
The surface imprinted technique was utilized in creating the synthetic lysozyme receptors on the poly(hydroxyethyl methacrylate) [p(HEMA)] cryogel membrane with the assistance of polydopamine under alkaline conditions. Following the design of the artificial receptors, Fourier-transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and the swelling test were used for the characterization studies and the lysozyme adsorption capability of the adsorbent was evaluated in the aqueous solution. The maximum adsorption capacity (Qmax) of lysozyme was found as 108.9 mg/g and the adsorption of the target protein on the adsorbent was monolayer and showed a good fit to the Langmuir isotherm model. The IF factor was 3.26 and the adsorbent was highly selective against creatinine and bovine serum albumin (BSA). Furthermore, the adsorbent maintained its stability after 5 adsorption, desorption, and regeneration cycles.
{"title":"Lysozyme Imprinted poly(hydroxyethyl methacrylate) Cryogel Membrane With the Assistance of polydopamine","authors":"A. A. Topcu","doi":"10.17350/hjse19030000294","DOIUrl":"https://doi.org/10.17350/hjse19030000294","url":null,"abstract":"The surface imprinted technique was utilized in creating the synthetic lysozyme receptors on the poly(hydroxyethyl methacrylate) [p(HEMA)] cryogel membrane with the assistance of polydopamine under alkaline conditions. Following the design of the artificial receptors, Fourier-transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and the swelling test were used for the characterization studies and the lysozyme adsorption capability of the adsorbent was evaluated in the aqueous solution. \u0000The maximum adsorption capacity (Qmax) of lysozyme was found as 108.9 mg/g and the adsorption of the target protein on the adsorbent was monolayer and showed a good fit to the Langmuir isotherm model. The IF factor was 3.26 and the adsorbent was highly selective against creatinine and bovine serum albumin (BSA). Furthermore, the adsorbent maintained its stability after 5 adsorption, desorption, and regeneration cycles.","PeriodicalId":285705,"journal":{"name":"Hittite Journal of Science and Engineering","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132356613","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：