Abstract Napoleonaea imperialis rinds were separated from the seeds and extracted via maceration using methanol. The crude methanol extract was partitioned with n-hexane and dichloromethane to yield n-hexane fraction (11.01 g), dichloromethane fraction (35.16 g) and methanol fraction (101.75 g). Dichloromethane fraction was chromatographed and purified to give a compound whose structure was elucidated using one-dimension and two-dimension nuclear magnetic resonance (NMR) experiments. The isolated compound was characterized as glycosylated stigmasterol.
{"title":"Glycosylated stigmasterol from the rind of Napoleonaea imperialis","authors":"G. Ndukwe, I. Jack, R. E. Ekong","doi":"10.2478/auoc-2022-0001","DOIUrl":"https://doi.org/10.2478/auoc-2022-0001","url":null,"abstract":"Abstract Napoleonaea imperialis rinds were separated from the seeds and extracted via maceration using methanol. The crude methanol extract was partitioned with n-hexane and dichloromethane to yield n-hexane fraction (11.01 g), dichloromethane fraction (35.16 g) and methanol fraction (101.75 g). Dichloromethane fraction was chromatographed and purified to give a compound whose structure was elucidated using one-dimension and two-dimension nuclear magnetic resonance (NMR) experiments. The isolated compound was characterized as glycosylated stigmasterol.","PeriodicalId":19641,"journal":{"name":"Ovidius University Annals of Chemistry","volume":"C-18 1","pages":"1 - 6"},"PeriodicalIF":0.9,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85050873","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}
S. Adoga, O. Igbum, Glory Okopi, B. A. Ikyenge, Okwori Isaacs Ochi, P. Ode
Abstract Dealing effectively with plastic wastes has been a major global challenge. Different methods have been previously employed to proffer solution to plastic wastes problem however, all showed their energetic, economic and environmental implications. In this research, catalytic pyrolysis of low density polyethylene and polypropylene wastes was carried out to proffer solution to the problem. The plastic materials were collected and appropriately prepared after which ultimate and proximate analysis was carried out on them. The clay was collected from Naka, Gwer West Local Government Area of Benue State, Nigeria, thereafter, referred to as N-clay and was appropriately prepared, then analyzed by a BET analyzer for the following properties: the surface area, which was found to be 85.418 m2/g, pore size 2.100 nm and pore volume of 0.042 cc/g. Also, the XRF determination of the chemical composition of the N-clay was done and the SiO2/Al2O3 ratio was found to be 70.81/29.19. The N-clay and the plastics were then pyrolyzed in a chemical vapor deposition (CVD) reactor in the ratio 1:3 respectively, at 500 oC with residence time of 30 min using nitrogen as purge gas. The polypropylene yielded 70.34 % liquid oil, 6.43 % char and 23.23 % gas. The liquid was analyzed for functional groups, using Raman spectrometer. Physicochemical analysis was also done on the oil and it was determined that the oil had properties consistent with commercial-grade gasoline. The low density polyethylene yielded wax, instead of liquid, char and gas. Finally, it was concluded that the N-clay was suitable as catalyst for the pyrolysis of plastics and the fuel oil obtained from polypropylene pyrolysis is comparable to gasoline fuel.
有效处理塑料垃圾一直是全球面临的一项重大挑战。以前已经采用了不同的方法来解决塑料垃圾问题，然而，所有的方法都显示了它们的能源、经济和环境影响。本研究通过对低密度聚乙烯和聚丙烯废弃物进行催化热解来解决这一问题。收集并适当制备塑料材料，然后对其进行最终和近似分析。该粘土采自尼日利亚贝努埃州Gwer West Local Government Area的Naka，经适当制备后称为N-clay，经BET分析仪分析，其比表面积为85.418 m2/g，孔径为2.100 nm，孔体积为0.042 cc/g。对n -粘土的化学成分进行了XRF测定，SiO2/Al2O3的比值为70.81/29.19。然后在化学气相沉积(CVD)反应器中，以氮气为吹扫气体，在500℃下，以1:3的比例分别热解n -粘土和塑料，停留时间为30 min。聚丙烯产油率为液态油70.34%，炭6.43%，气23.23%。用拉曼光谱仪分析液体中的官能团。对该油进行了理化分析，确定该油具有与商品级汽油一致的性能。低密度聚乙烯产生的是蜡，而不是液体、炭和气体。最后得出n -粘土适合作为塑料热解的催化剂，聚丙烯热解得到的燃料油与汽油燃料相当。
{"title":"Catalytic pyrolysis of low density polyethylene and polypropylene wastes to fuel oils by N-clay","authors":"S. Adoga, O. Igbum, Glory Okopi, B. A. Ikyenge, Okwori Isaacs Ochi, P. Ode","doi":"10.2478/auoc-2022-0007","DOIUrl":"https://doi.org/10.2478/auoc-2022-0007","url":null,"abstract":"Abstract Dealing effectively with plastic wastes has been a major global challenge. Different methods have been previously employed to proffer solution to plastic wastes problem however, all showed their energetic, economic and environmental implications. In this research, catalytic pyrolysis of low density polyethylene and polypropylene wastes was carried out to proffer solution to the problem. The plastic materials were collected and appropriately prepared after which ultimate and proximate analysis was carried out on them. The clay was collected from Naka, Gwer West Local Government Area of Benue State, Nigeria, thereafter, referred to as N-clay and was appropriately prepared, then analyzed by a BET analyzer for the following properties: the surface area, which was found to be 85.418 m2/g, pore size 2.100 nm and pore volume of 0.042 cc/g. Also, the XRF determination of the chemical composition of the N-clay was done and the SiO2/Al2O3 ratio was found to be 70.81/29.19. The N-clay and the plastics were then pyrolyzed in a chemical vapor deposition (CVD) reactor in the ratio 1:3 respectively, at 500 oC with residence time of 30 min using nitrogen as purge gas. The polypropylene yielded 70.34 % liquid oil, 6.43 % char and 23.23 % gas. The liquid was analyzed for functional groups, using Raman spectrometer. Physicochemical analysis was also done on the oil and it was determined that the oil had properties consistent with commercial-grade gasoline. The low density polyethylene yielded wax, instead of liquid, char and gas. Finally, it was concluded that the N-clay was suitable as catalyst for the pyrolysis of plastics and the fuel oil obtained from polypropylene pyrolysis is comparable to gasoline fuel.","PeriodicalId":19641,"journal":{"name":"Ovidius University Annals of Chemistry","volume":"59 1","pages":"50 - 55"},"PeriodicalIF":0.9,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84003105","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}
Abstract A series of novel poly(α-methyl β-alanine-b-lactone)s were prepared by a combination of hydrogen-transfer polymerization (HTP) of methacrylamide (MAm) and anionic ring-opening polymerization (AROP) of β-propiolactone (BPL), β-butyrolactone (BBL), and δ-valerolactone (DVL). For this purpose, poly(α-methyl β-alanine) (PmBA) having a living anionic end-group for a further extension was obtained via HTP of MAm. The anionic end-group on PmBA chains were used as initiation sites for AROP of BPL, BBL, and DVL. Fourier Transform Infrared Spectroscopy (FTIR) and Proton Nuclear Magnetic Resonance Spectroscopy (1H-NMR) confirmed the existence of both ester and α-methyl β-alanine (mBA) units in the final products. MALDI-MS analysis revealed that the poly(α-methyl β-alanine-b-lactone)s with average molar masses of several thousand g·mol−1 were obtained. DSC and TGA thermograms of each copolymer showed that the copolymers comprised the mBA and the corresponding ester units.
{"title":"Synthesis and characterization of novel poly(α-methyl β-alanine-b-lactone)s through hydrogen-transfer and ring-opening polymerization","authors":"E. Çatıker, Songül Kirlak, M. Atakay, B. Salih","doi":"10.2478/auoc-2022-0011","DOIUrl":"https://doi.org/10.2478/auoc-2022-0011","url":null,"abstract":"Abstract A series of novel poly(α-methyl β-alanine-b-lactone)s were prepared by a combination of hydrogen-transfer polymerization (HTP) of methacrylamide (MAm) and anionic ring-opening polymerization (AROP) of β-propiolactone (BPL), β-butyrolactone (BBL), and δ-valerolactone (DVL). For this purpose, poly(α-methyl β-alanine) (PmBA) having a living anionic end-group for a further extension was obtained via HTP of MAm. The anionic end-group on PmBA chains were used as initiation sites for AROP of BPL, BBL, and DVL. Fourier Transform Infrared Spectroscopy (FTIR) and Proton Nuclear Magnetic Resonance Spectroscopy (1H-NMR) confirmed the existence of both ester and α-methyl β-alanine (mBA) units in the final products. MALDI-MS analysis revealed that the poly(α-methyl β-alanine-b-lactone)s with average molar masses of several thousand g·mol−1 were obtained. DSC and TGA thermograms of each copolymer showed that the copolymers comprised the mBA and the corresponding ester units.","PeriodicalId":19641,"journal":{"name":"Ovidius University Annals of Chemistry","volume":"38 1","pages":"78 - 83"},"PeriodicalIF":0.9,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73974148","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}
Abstract Chicken feathers were used to reinforce low density polyethylene (LDPE) and polypropylene (PP). The physico-mechanical and flame retardation properties of the composites were investigated. Properties such as tensile strength, elongation at break, flexural strength, and modulus as well as water absorbency were determined and the results obtained were analyzed. The composites were further characterized by SEM and FTIR analyses to study the surface morphology and evidence of composite formation respectively. The Young modulus of reinforced composites were greater than that of virgin samples. The fiber/Polypropylene samples were observed to have the highest value of Young modulus, with a value of 133.33 GPa, and tensile strength value of 16.93 MPa. TGA and flame retardant tests were carried out to investigate the flame propagation and thermal properties of the composites. The results showed that the mechanical properties of composites from polypropylene were better enhanced than those from the composites of polyethylene, with an overall increase in mechanical properties when compared to the virgin polymers used. From the TGA and flame retardant test, it was observed that the more the fiber load the more the formation of char layers in the samples, hence retards the flame formation and reduced prolonged burning and flame propagation.
{"title":"Preparation and physico-chemical study of fire retardant from chicken feathers and PP/PE composites","authors":"A. D. Mohammed, Y. Alhassan","doi":"10.2478/auoc-2022-0010","DOIUrl":"https://doi.org/10.2478/auoc-2022-0010","url":null,"abstract":"Abstract Chicken feathers were used to reinforce low density polyethylene (LDPE) and polypropylene (PP). The physico-mechanical and flame retardation properties of the composites were investigated. Properties such as tensile strength, elongation at break, flexural strength, and modulus as well as water absorbency were determined and the results obtained were analyzed. The composites were further characterized by SEM and FTIR analyses to study the surface morphology and evidence of composite formation respectively. The Young modulus of reinforced composites were greater than that of virgin samples. The fiber/Polypropylene samples were observed to have the highest value of Young modulus, with a value of 133.33 GPa, and tensile strength value of 16.93 MPa. TGA and flame retardant tests were carried out to investigate the flame propagation and thermal properties of the composites. The results showed that the mechanical properties of composites from polypropylene were better enhanced than those from the composites of polyethylene, with an overall increase in mechanical properties when compared to the virgin polymers used. From the TGA and flame retardant test, it was observed that the more the fiber load the more the formation of char layers in the samples, hence retards the flame formation and reduced prolonged burning and flame propagation.","PeriodicalId":19641,"journal":{"name":"Ovidius University Annals of Chemistry","volume":"33 1","pages":"71 - 77"},"PeriodicalIF":0.9,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82555792","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}
Abstract The synthesis of poly(ε-caprolactone) (PCL) tetra-arm star polymer was carried out using “click” chemistry and ring-opening polymerization techniques. For this purpose, poly(ε-caprolactone) azido (PCL-N3) was acquired using ring-opening polymerization of ε-caprolactone and 2-[2-(2-azidoethoxy)ethoxy]ethanol (N3ol). N3ol was obtained using sodium azide and 2-[2-(2-chloroethoxy)ethoxy]ethanol. 4-(prop-2-ynyloxy)-phthalonitrile was obtained by using 4-nitrophthalonitrile and propargyl alcohol. 2(3),9(10),16(17),23(24) Tetrakis-[(prop-2-ynyloxy)-phthalocyaninato]zinc(II) (Pc-propargyl) was synthesized by using 4-(prop-2-ynyloxy)-phthalonitrile and a metal salt. By reacting Pc-propargyl and PCL-N3, PCL tetra-arm star polymer was obtained by “click” chemistry. The products were characterized via scanning electron microscopy, 1H-nuclear magnetic resonance spectroscopy, ultraviolet-visible spectrophotometry, Fourier-transform infrared spectroscopy, and gel permeation chromatography instruments. The spectroscopic analyses of PCL tetra-arm star polymer prove that the star polymer was built through the combination of ROP and “click” chemistry. We provided a protocol for PCL tetra-arm star polymer, and a statement of reproducibility with respect to the properties of this tetra-arm star polymer. This study is an example of a novel type of combination reaction, from ring-opening polymerization to “click” chemistry using phthalocyanine. This can open the door for diverse tetra-arm star polymer synthesis that could potentially cause major advances in synthetic macromolecular chemistry.
{"title":"Synthesis and characterization of poly(ε-caprolactone) tetra-arm star polymer using tetra terminal alkynyl-substituted phthalocyanine by the combination of ring-opening polymerization and “click” chemistry","authors":"B. Savaş, E. Meyvacı, T. Öztürk, M. Ağırtaş","doi":"10.2478/auoc-2022-0003","DOIUrl":"https://doi.org/10.2478/auoc-2022-0003","url":null,"abstract":"Abstract The synthesis of poly(ε-caprolactone) (PCL) tetra-arm star polymer was carried out using “click” chemistry and ring-opening polymerization techniques. For this purpose, poly(ε-caprolactone) azido (PCL-N3) was acquired using ring-opening polymerization of ε-caprolactone and 2-[2-(2-azidoethoxy)ethoxy]ethanol (N3ol). N3ol was obtained using sodium azide and 2-[2-(2-chloroethoxy)ethoxy]ethanol. 4-(prop-2-ynyloxy)-phthalonitrile was obtained by using 4-nitrophthalonitrile and propargyl alcohol. 2(3),9(10),16(17),23(24) Tetrakis-[(prop-2-ynyloxy)-phthalocyaninato]zinc(II) (Pc-propargyl) was synthesized by using 4-(prop-2-ynyloxy)-phthalonitrile and a metal salt. By reacting Pc-propargyl and PCL-N3, PCL tetra-arm star polymer was obtained by “click” chemistry. The products were characterized via scanning electron microscopy, 1H-nuclear magnetic resonance spectroscopy, ultraviolet-visible spectrophotometry, Fourier-transform infrared spectroscopy, and gel permeation chromatography instruments. The spectroscopic analyses of PCL tetra-arm star polymer prove that the star polymer was built through the combination of ROP and “click” chemistry. We provided a protocol for PCL tetra-arm star polymer, and a statement of reproducibility with respect to the properties of this tetra-arm star polymer. This study is an example of a novel type of combination reaction, from ring-opening polymerization to “click” chemistry using phthalocyanine. This can open the door for diverse tetra-arm star polymer synthesis that could potentially cause major advances in synthetic macromolecular chemistry.","PeriodicalId":19641,"journal":{"name":"Ovidius University Annals of Chemistry","volume":"8 1","pages":"17 - 22"},"PeriodicalIF":0.9,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79569865","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}
Abstract A study of the flow behavior of Algerian crude oils obtained from different fields in the TFT region (Tin Fouye Tabankort/South Algeria) was conducted using the AR2000 rheometer equipped with a Couette geometry. Rheology experiments were carried out at different shear rates and temperatures to predict the transport characteristics of crude oils. The results obtained show that all crude oils studied exhibit non-Newtonian behavior at low shear rates and quasi-Newtonian behavior at high values of the shear rate gradient. The analysis of the obtained rheological data revealed that the increase in temperature had a positive effect on the flow behavior of crude oils in pipelines.
{"title":"Flow behavior of Algerian crude oils from different sources","authors":"Ahmed Salah Eddine Meddour, Farid Souas","doi":"10.2478/auoc-2022-0009","DOIUrl":"https://doi.org/10.2478/auoc-2022-0009","url":null,"abstract":"Abstract A study of the flow behavior of Algerian crude oils obtained from different fields in the TFT region (Tin Fouye Tabankort/South Algeria) was conducted using the AR2000 rheometer equipped with a Couette geometry. Rheology experiments were carried out at different shear rates and temperatures to predict the transport characteristics of crude oils. The results obtained show that all crude oils studied exhibit non-Newtonian behavior at low shear rates and quasi-Newtonian behavior at high values of the shear rate gradient. The analysis of the obtained rheological data revealed that the increase in temperature had a positive effect on the flow behavior of crude oils in pipelines.","PeriodicalId":19641,"journal":{"name":"Ovidius University Annals of Chemistry","volume":"16 1","pages":"64 - 70"},"PeriodicalIF":0.9,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82928121","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}
Abstract Worldwide, one of the most consumed fruit juices is apple juice, preferred by both adults and children due to its authentic taste, but also due to its nutritional and health benefits. Apple juice contains sugars, malic acid, soluble pectin, vitamin C, phytochemicals and minerals. The production process influences the juice composition. There is a growing market for natural cloudy apple juice, even though fruit juice is mostly consumed as clear juice. The aim of this study was to obtain cloudy apple juice by using a blender and a cold pressing juicer for extraction and to evaluate their physico-chemical and sensory qualities. The apple juice samples were obtained from three different apple cultivars: “Gala”, “Braeburn” and “Golden Delicious”. After extraction, apple juice samples were pasteurized and cooled. In this study, physico-chemical analyzes (like moisture, water activity, pH, titratable acidity, total soluble solids, electrical conductivity, color parameters) were performed immediately after processing and at 7, 14, 21 days of storage at room temperature. The results showed that the investigated parameters of the apple juice samples varied differently depending on both the apple cultivar and the processing method used. Sensory analysis showed that certain types of apples can be suitable for extracting juice using a blender (“Golden Delicious”), while others such as “Gala” apples can be used to obtain juice by cold pressing.
{"title":"Physico-chemical and sensory quality of pasteurized apple juices extracted by blender and cold pressing juicer","authors":"C. Ghinea, A. Prisacaru, A. Leahu","doi":"10.2478/auoc-2022-0012","DOIUrl":"https://doi.org/10.2478/auoc-2022-0012","url":null,"abstract":"Abstract Worldwide, one of the most consumed fruit juices is apple juice, preferred by both adults and children due to its authentic taste, but also due to its nutritional and health benefits. Apple juice contains sugars, malic acid, soluble pectin, vitamin C, phytochemicals and minerals. The production process influences the juice composition. There is a growing market for natural cloudy apple juice, even though fruit juice is mostly consumed as clear juice. The aim of this study was to obtain cloudy apple juice by using a blender and a cold pressing juicer for extraction and to evaluate their physico-chemical and sensory qualities. The apple juice samples were obtained from three different apple cultivars: “Gala”, “Braeburn” and “Golden Delicious”. After extraction, apple juice samples were pasteurized and cooled. In this study, physico-chemical analyzes (like moisture, water activity, pH, titratable acidity, total soluble solids, electrical conductivity, color parameters) were performed immediately after processing and at 7, 14, 21 days of storage at room temperature. The results showed that the investigated parameters of the apple juice samples varied differently depending on both the apple cultivar and the processing method used. Sensory analysis showed that certain types of apples can be suitable for extracting juice using a blender (“Golden Delicious”), while others such as “Gala” apples can be used to obtain juice by cold pressing.","PeriodicalId":19641,"journal":{"name":"Ovidius University Annals of Chemistry","volume":"1 1","pages":"84 - 93"},"PeriodicalIF":0.9,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88897577","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}
Abstract This study provides a comparative assessment of cadmium (Cd), lead (Pb), chromium (Cr), nickel (Ni), copper (Cu), manganese (Mn), zinc (Zn), and iron (Fe) pollution occurrence, sources, and exposure risk in soils from selected abandoned sites. The concentrations of metals were determined using atomic absorption spectrophotometry. The metals occurrence ranged from 0.02 (Zn) to 16600 mg kg−1 (Fe) in the order of subsoil > topsoil with petroleum tank farm and fuel/gas service station exhibiting high metal loading. The sources of metals are anthropogenic and geologic. The hazard index values for infants’ were higher than that of adults, and the inhalation risk for adults’ was considerably higher than for infants’ exposure. The ecological risk of Cd, Pb, Cr, Ni, and Zn falls in the contamination to pollution index. This study revealed the need for clean-up and restoration of abandoned site soils.
{"title":"Toxic metals in soil depths from selected abandoned sites: Occurrence, sources, ecological and human health risk","authors":"O. O. Emoyan, G. Tesi, E. Ohwo, C. Olisah","doi":"10.2478/auoc-2022-0002","DOIUrl":"https://doi.org/10.2478/auoc-2022-0002","url":null,"abstract":"Abstract This study provides a comparative assessment of cadmium (Cd), lead (Pb), chromium (Cr), nickel (Ni), copper (Cu), manganese (Mn), zinc (Zn), and iron (Fe) pollution occurrence, sources, and exposure risk in soils from selected abandoned sites. The concentrations of metals were determined using atomic absorption spectrophotometry. The metals occurrence ranged from 0.02 (Zn) to 16600 mg kg−1 (Fe) in the order of subsoil > topsoil with petroleum tank farm and fuel/gas service station exhibiting high metal loading. The sources of metals are anthropogenic and geologic. The hazard index values for infants’ were higher than that of adults, and the inhalation risk for adults’ was considerably higher than for infants’ exposure. The ecological risk of Cd, Pb, Cr, Ni, and Zn falls in the contamination to pollution index. This study revealed the need for clean-up and restoration of abandoned site soils.","PeriodicalId":19641,"journal":{"name":"Ovidius University Annals of Chemistry","volume":"69 1","pages":"7 - 16"},"PeriodicalIF":0.9,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86154354","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}
Abstract The analysis deals with the thermo-hydraulic performance of a Gasket Plate Heat Exchanger used for cooling vegetable oils with a water-ethylene glycol 50% and volume fractions of non-spherical nanoparticles mixture as a refrigerant. The heat exchanger has 75 plates with a chevron angle equal to 30º. The Reynolds number of the refrigerant varies from 80 to 1530. The Reynolds number of the sunflower vegetable oil is fixed and equal to 30. The non-spherical nanoparticles used for analysis are platelet, cylindrical and brick types. Graphical results are presented for global heat transfer coefficient, heat capacity ratio, heat transfer rate, outlet temperatures, thermal and viscous entropy generation rate, and Bejan thermodynamic number. The results obtained allow us to conclude that it is possible to work with low relative flow rates using non-spherical nanoparticles, emphasizing platelet nanoparticles. The entropy generations analysis shows that very high flow rates of the refrigerant dissipate much of the energy in viscous form and do not contribute to oil cooling, with a consequent increase in the heat exchanger operating costs.
{"title":"Entropy generation analysis in a gasket plate heat exchanger using non-spherical shape of alumina boehmite nanoparticles","authors":"E. Nogueira","doi":"10.2478/auoc-2022-0006","DOIUrl":"https://doi.org/10.2478/auoc-2022-0006","url":null,"abstract":"Abstract The analysis deals with the thermo-hydraulic performance of a Gasket Plate Heat Exchanger used for cooling vegetable oils with a water-ethylene glycol 50% and volume fractions of non-spherical nanoparticles mixture as a refrigerant. The heat exchanger has 75 plates with a chevron angle equal to 30º. The Reynolds number of the refrigerant varies from 80 to 1530. The Reynolds number of the sunflower vegetable oil is fixed and equal to 30. The non-spherical nanoparticles used for analysis are platelet, cylindrical and brick types. Graphical results are presented for global heat transfer coefficient, heat capacity ratio, heat transfer rate, outlet temperatures, thermal and viscous entropy generation rate, and Bejan thermodynamic number. The results obtained allow us to conclude that it is possible to work with low relative flow rates using non-spherical nanoparticles, emphasizing platelet nanoparticles. The entropy generations analysis shows that very high flow rates of the refrigerant dissipate much of the energy in viscous form and do not contribute to oil cooling, with a consequent increase in the heat exchanger operating costs.","PeriodicalId":19641,"journal":{"name":"Ovidius University Annals of Chemistry","volume":"24 1","pages":"41 - 49"},"PeriodicalIF":0.9,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76955435","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}
Abstract Studies suggest that extracts from plant materials could play protective roles against various disorders associated with the interplay between oxidative response and inflammatory disorders. The aim of this study was to investigate the potential antioxidant and anti-inflammatory properties, and phytochemical analyses of methanol extract of ripe and unripe peels of Ananas comosus (L.) Merr. The antioxidant properties were investigated through the analyses of ferric ion reducing antioxidant capacities, ascorbic acid equivalent antioxidant capacities, and nitric oxide scavenging capacities of the extracts. The anti-inflammatory potentials of the extracts were assessed through albumin denaturation inhibition and proteinase inhibition assays. Further investigation was carried out on the phytochemical composition of the extracts. There was no significant difference in the antioxidant potentials of the extracts assessed through the reduction of ferric ion. However, the ascorbic acid equivalent capacities and nitric oxide scavenging potential revealed that the antioxidant potentials of the extract of the unripe peel of A. comosus were significantly higher (p < 0.05) than the antioxidant potentials of the extract of ripe peel. Albumin denaturation inhibitory potential was significantly higher (p < 0.05), but there was no significant difference in the protease inhibitory potentials of both extracts. The estimated amounts of total flavonoids present in the extract of ripe peel of A. comosus were significantly higher (p < 0.05) than the estimates in the extract of unripe peels. This study gave a comprehensive insight into the antioxidant properties, anti-inflammatory properties and phytochemical compositions of the methanol extracts of the peels of ripe and unripe A. comosus which could be exploited as an alternative and complementary medicine in the treatment of different ailments associated with inflammatory disorders.
{"title":"Antioxidant potentials and anti-inflammatory properties of methanol extracts of ripe and unripe peels of Ananas comosus (L.) Merr.","authors":"B. Oso, I. Olaoye, Emmanuel N. Ekpo, G. Akhigbe","doi":"10.2478/auoc-2022-0013","DOIUrl":"https://doi.org/10.2478/auoc-2022-0013","url":null,"abstract":"Abstract Studies suggest that extracts from plant materials could play protective roles against various disorders associated with the interplay between oxidative response and inflammatory disorders. The aim of this study was to investigate the potential antioxidant and anti-inflammatory properties, and phytochemical analyses of methanol extract of ripe and unripe peels of Ananas comosus (L.) Merr. The antioxidant properties were investigated through the analyses of ferric ion reducing antioxidant capacities, ascorbic acid equivalent antioxidant capacities, and nitric oxide scavenging capacities of the extracts. The anti-inflammatory potentials of the extracts were assessed through albumin denaturation inhibition and proteinase inhibition assays. Further investigation was carried out on the phytochemical composition of the extracts. There was no significant difference in the antioxidant potentials of the extracts assessed through the reduction of ferric ion. However, the ascorbic acid equivalent capacities and nitric oxide scavenging potential revealed that the antioxidant potentials of the extract of the unripe peel of A. comosus were significantly higher (p < 0.05) than the antioxidant potentials of the extract of ripe peel. Albumin denaturation inhibitory potential was significantly higher (p < 0.05), but there was no significant difference in the protease inhibitory potentials of both extracts. The estimated amounts of total flavonoids present in the extract of ripe peel of A. comosus were significantly higher (p < 0.05) than the estimates in the extract of unripe peels. This study gave a comprehensive insight into the antioxidant properties, anti-inflammatory properties and phytochemical compositions of the methanol extracts of the peels of ripe and unripe A. comosus which could be exploited as an alternative and complementary medicine in the treatment of different ailments associated with inflammatory disorders.","PeriodicalId":19641,"journal":{"name":"Ovidius University Annals of Chemistry","volume":"16 1","pages":"94 - 98"},"PeriodicalIF":0.9,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91278587","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}
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