The present paper examines the emissions of polycyclic aromatic hydrocarbons (PAHs) resulted from the thermal treatment through pyrolysis process of contaminated soil with petroleum products. Specifically, across the experimental work, the process temperature influence on PAHs and Phenanthrene emissions and remediation degree during the thermal treatment were investigated. The pyrolytic treatment of the contaminated soils was performed at different temperatures and time: 400C for 60 min; 600C for 30 min and 800C for 30 min. The obtained results revealed that non-oxidative atmosphere at temperatures between 400C and 800C reduced PAHs and Phenanthrene to below regulatory standards. More than that, it was evidenced that, when the initial concentration of the contaminants in soil is not too high (content of PAHs in soil was 26.811 mg/kgd.w. respect to 25 mg/kgd.w., while for Phenanthrene initial concentration in soil was 19.264 mg/kgd.w. respect to 5 mg/kgd.w. from the regulation in force) even a low-temperature of 400C for the pyrolysis process ensure an efficiency in removing PAHs and Phenanthrene higher than 99%. It was evidenced that, increasing the process temperature with 200C and respectively with 400C, respect to the selected pyrolysis conditions as appropriate (400C for 60 minutes), has no relevance in terms of reducing contaminants from the contaminated soil. This is an important advantage considering that lower temperatures are requiring lower energy costs and soil fertility is not affected as in case of soil incineration or other thermal treatment methods.
{"title":"Evaluation of the Emissions from the Pyrolytic Treatment of PAHs Soil Contaminated Soil","authors":"D. Cocarta, A. Velcea, C. Stan, A. Badea","doi":"10.11159/ICEPR19.126","DOIUrl":"https://doi.org/10.11159/ICEPR19.126","url":null,"abstract":"The present paper examines the emissions of polycyclic aromatic hydrocarbons (PAHs) resulted from the thermal treatment through pyrolysis process of contaminated soil with petroleum products. Specifically, across the experimental work, the process temperature influence on PAHs and Phenanthrene emissions and remediation degree during the thermal treatment were investigated. The pyrolytic treatment of the contaminated soils was performed at different temperatures and time: 400C for 60 min; 600C for 30 min and 800C for 30 min. The obtained results revealed that non-oxidative atmosphere at temperatures between 400C and 800C reduced PAHs and Phenanthrene to below regulatory standards. More than that, it was evidenced that, when the initial concentration of the contaminants in soil is not too high (content of PAHs in soil was 26.811 mg/kgd.w. respect to 25 mg/kgd.w., while for Phenanthrene initial concentration in soil was 19.264 mg/kgd.w. respect to 5 mg/kgd.w. from the regulation in force) even a low-temperature of 400C for the pyrolysis process ensure an efficiency in removing PAHs and Phenanthrene higher than 99%. It was evidenced that, increasing the process temperature with 200C and respectively with 400C, respect to the selected pyrolysis conditions as appropriate (400C for 60 minutes), has no relevance in terms of reducing contaminants from the contaminated soil. This is an important advantage considering that lower temperatures are requiring lower energy costs and soil fertility is not affected as in case of soil incineration or other thermal treatment methods.","PeriodicalId":265434,"journal":{"name":"Proceedings of the 5th World Congress on New Technologies","volume":"106 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124908011","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}
Extended Abstract Salvianic acid A (SAA, 3-(3',4'-dihydroxyphenyl)-2-hydroxypropanoic acid), as the main bioactive component of traditional Chinese herb Salvia miltiorrhiza, has important application value in the treatment of cardiovascular diseases . Traditionally, SAA was mainly isolated from dried root of S. miltiorrhiza by a water-extraction process. However, the amount of SAA in crude root is very low (0.045%), which restricted its large-scale applications. Although several chemical methods for SAA synthesis have been developed, these methods also suffered from intractable enantioselectivities, complicated procedure, and environmental pollution . Therefore, developing efficient and eco-friendly methods for SAA production was highly desirable. In this study, a two-step biocatalytic cascade reaction to produce SAA from inexpensive L-dopa with high efficiency by using whole-cell biocatalysts was developed. In the first step, the recombinant Escherichia coli cells expressing mL-AAD from Proteus vulgaris (BL21(DE3)-pET-28a-mlaad) were employed to deaminize L-dopa to form 3,4dihydroxyphenylalanine (DHPPA). Subsequently, the permeabilized recombinant E. coli cells co-expression of d-lactate dehydrogenase (d-LDH) from Pediococcus acidilactici and FDH from Mycobacterium vaccae N10 (NADH regeneration system) (BL21(DE3)-pETDuet-pddh-fdh) were used to convert DHPPA in the raw reaction solution to SAA. Results: (1) The effect of bioconversion conditions for BL21(DE3)-pET-28a-mlaad to convert L-dopa to DHPPA were evaluated firstly. The optimal conditions for the deamination reaction were as follows: 0.42 g/L cell biomass, 50 mM Ldopa, 37 °C, pH 7.5 and 160 min (operation time). (2) To overcome the permeability barrier of cell envelope to substrates and products, the hexane-permeabilized BL21(DE3)-pETDuet-pddh-fdh was used to convert DHPPA to SAA. The optimal pH and temperature for the reaction were 6.0 and 30 °C, respectively. (3) Two-step catalytic synthesis of SAA from L-dopa: DHPPA was prepared with BL21(DE3)-pET-28a-mlaad under the optimum deamination conditions described above, and 48.6 mM DHPPA was obtained from 50 mM L-dopa. Next, the recombinant BL21(DE3)-pET-28a-mlaad cells were removed from the reaction solution by centrifugation, 100 mM sodium formate were added and the reaction pH value was adjusted to 5.5. Then 0.31-0.93 mg/mL permeabilized BL21(DE3)-pETDuet-pddh-fdh were added to the reaction solution to start the conversion of DHPPA to SAA. The yields of SAA from DHPPA in our experimental ranges could all reach more than 97.7%, and the SAA production rate was accelerated with increasing cell concentration. When cell concentration above 0.62 mg/mL, DHPPA could almost be converted to SAA in 4.5 h. In case of 0.31 mg/mL cell concentration, SAA production rate from DHPPA could over 97.7% after 5.5 h. Overall, in our developed a two-step biotransformation process, L-dopa was efficiently deaminized to DHPPA with a high yield of 97.7 % in mL-AAD b
{"title":"Biosynthesis of Salvianic Acid from L-Dopa via a Two-Step Process","authors":"Weirui Zhao, K. Hu, Jiaqi Mei, L. Mei","doi":"10.11159/ICBB19.142","DOIUrl":"https://doi.org/10.11159/ICBB19.142","url":null,"abstract":"Extended Abstract Salvianic acid A (SAA, 3-(3',4'-dihydroxyphenyl)-2-hydroxypropanoic acid), as the main bioactive component of traditional Chinese herb Salvia miltiorrhiza, has important application value in the treatment of cardiovascular diseases . Traditionally, SAA was mainly isolated from dried root of S. miltiorrhiza by a water-extraction process. However, the amount of SAA in crude root is very low (0.045%), which restricted its large-scale applications. Although several chemical methods for SAA synthesis have been developed, these methods also suffered from intractable enantioselectivities, complicated procedure, and environmental pollution . Therefore, developing efficient and eco-friendly methods for SAA production was highly desirable. In this study, a two-step biocatalytic cascade reaction to produce SAA from inexpensive L-dopa with high efficiency by using whole-cell biocatalysts was developed. In the first step, the recombinant Escherichia coli cells expressing mL-AAD from Proteus vulgaris (BL21(DE3)-pET-28a-mlaad) were employed to deaminize L-dopa to form 3,4dihydroxyphenylalanine (DHPPA). Subsequently, the permeabilized recombinant E. coli cells co-expression of d-lactate dehydrogenase (d-LDH) from Pediococcus acidilactici and FDH from Mycobacterium vaccae N10 (NADH regeneration system) (BL21(DE3)-pETDuet-pddh-fdh) were used to convert DHPPA in the raw reaction solution to SAA. Results: (1) The effect of bioconversion conditions for BL21(DE3)-pET-28a-mlaad to convert L-dopa to DHPPA were evaluated firstly. The optimal conditions for the deamination reaction were as follows: 0.42 g/L cell biomass, 50 mM Ldopa, 37 °C, pH 7.5 and 160 min (operation time). (2) To overcome the permeability barrier of cell envelope to substrates and products, the hexane-permeabilized BL21(DE3)-pETDuet-pddh-fdh was used to convert DHPPA to SAA. The optimal pH and temperature for the reaction were 6.0 and 30 °C, respectively. (3) Two-step catalytic synthesis of SAA from L-dopa: DHPPA was prepared with BL21(DE3)-pET-28a-mlaad under the optimum deamination conditions described above, and 48.6 mM DHPPA was obtained from 50 mM L-dopa. Next, the recombinant BL21(DE3)-pET-28a-mlaad cells were removed from the reaction solution by centrifugation, 100 mM sodium formate were added and the reaction pH value was adjusted to 5.5. Then 0.31-0.93 mg/mL permeabilized BL21(DE3)-pETDuet-pddh-fdh were added to the reaction solution to start the conversion of DHPPA to SAA. The yields of SAA from DHPPA in our experimental ranges could all reach more than 97.7%, and the SAA production rate was accelerated with increasing cell concentration. When cell concentration above 0.62 mg/mL, DHPPA could almost be converted to SAA in 4.5 h. In case of 0.31 mg/mL cell concentration, SAA production rate from DHPPA could over 97.7% after 5.5 h. Overall, in our developed a two-step biotransformation process, L-dopa was efficiently deaminized to DHPPA with a high yield of 97.7 % in mL-AAD b","PeriodicalId":265434,"journal":{"name":"Proceedings of the 5th World Congress on New Technologies","volume":"173 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125795591","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}
Extended Abstract In recent years, deforestation in Southeast Asia has become a major issue. The main cause of deforestation is the development of plantations for producing raw materials for paper and palm oil products consumed daily. Palm oil is a vegetable oil obtained from the fruit of oil palm and is the most consumed vegetable oil in the world. Oil palms are endemic to the tropical regions, and in particular, Indonesia is a remarkable expansion of plantations, and it is currently the world's largest oil palm producer. The forest area of Sumatra island has been halved in the last 30 years, and Borneo island has lost a third and many wildlife have been designated as endangered species. When making a tropical rain forest into farmland, not only cutting down trees but also field burning is performed. It is known that the biomass burning plumes generated by large forest and agriculture fires in autumn in Indonesia [1, 2], causes severe public health problems [3]. Atmospheric aerosols play an important and complex role in the Earth's radiation budget, having both a direct and indirect effect, so it is necessary to study seasonal and regional variations [4]. Furthermore, to burn off the peat swamp forest, in a few days later, fires will also occur in other places. Since a large amount of carbon is emitted into the atmosphere by the fire, it is a big problem from the viewpoint of global warming. The purpose of this research is to clarify the relationship between fire occurrence frequency, geographical distribution, time variation, and substances generated, using satellite and ground based data. We first investigated the number of hotspots on Sumatra and Borneo calculated from satellite data. It was found that the year in which the number of forest occurrences was large was 2012 in Sumatra and 2006 in Borneo. The monthly mean values in the Borneo region of the optical thickness of the aerosol calculated from satellite data are very high at 1.93 in September 2015 and 1.65 in October. The smoke from the extensive fire that occurred in the dry season caused health damage in Indonesia and abroad. On the day of presentation, we will report the state of air pollution in Southeast Asia due to forest fires.
{"title":"Monitoring Of Biomass Burning Aerosols Characteristics in Southeast Asia from Space And/Or Ground","authors":"M. Yasumoto","doi":"10.11159/ICEPR19.188","DOIUrl":"https://doi.org/10.11159/ICEPR19.188","url":null,"abstract":"Extended Abstract In recent years, deforestation in Southeast Asia has become a major issue. The main cause of deforestation is the development of plantations for producing raw materials for paper and palm oil products consumed daily. Palm oil is a vegetable oil obtained from the fruit of oil palm and is the most consumed vegetable oil in the world. Oil palms are endemic to the tropical regions, and in particular, Indonesia is a remarkable expansion of plantations, and it is currently the world's largest oil palm producer. The forest area of Sumatra island has been halved in the last 30 years, and Borneo island has lost a third and many wildlife have been designated as endangered species. When making a tropical rain forest into farmland, not only cutting down trees but also field burning is performed. It is known that the biomass burning plumes generated by large forest and agriculture fires in autumn in Indonesia [1, 2], causes severe public health problems [3]. Atmospheric aerosols play an important and complex role in the Earth's radiation budget, having both a direct and indirect effect, so it is necessary to study seasonal and regional variations [4]. Furthermore, to burn off the peat swamp forest, in a few days later, fires will also occur in other places. Since a large amount of carbon is emitted into the atmosphere by the fire, it is a big problem from the viewpoint of global warming. The purpose of this research is to clarify the relationship between fire occurrence frequency, geographical distribution, time variation, and substances generated, using satellite and ground based data. We first investigated the number of hotspots on Sumatra and Borneo calculated from satellite data. It was found that the year in which the number of forest occurrences was large was 2012 in Sumatra and 2006 in Borneo. The monthly mean values in the Borneo region of the optical thickness of the aerosol calculated from satellite data are very high at 1.93 in September 2015 and 1.65 in October. The smoke from the extensive fire that occurred in the dry season caused health damage in Indonesia and abroad. On the day of presentation, we will report the state of air pollution in Southeast Asia due to forest fires.","PeriodicalId":265434,"journal":{"name":"Proceedings of the 5th World Congress on New Technologies","volume":"121 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129089019","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":"Smart Nanocarriers and Drug Delivery: Soft Interaction and Colloidal Stability in Complex Biological Media","authors":"D. Lombardo","doi":"10.11159/ICBB19.01","DOIUrl":"https://doi.org/10.11159/ICBB19.01","url":null,"abstract":"","PeriodicalId":265434,"journal":{"name":"Proceedings of the 5th World Congress on New Technologies","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127767060","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}
In this paper, the commercial software TracePro was used to investigate the effects of some factors on a conical cavity receiver, such as the conical angle, the number of loops of the helical tube, and the distance between the focal point of the collector and the aperture. These factors affect the optical efficiency, the maximum heat flux density, and the light distribution in the conical cavity. The optical performance of the conical receiver was studied and analyzed using the Monte Carlo ray tracing method. The results showed that the amount of light rays reaching the helical tube increases with the increasing of the conical angle, while the optical efficiency decreases and the maximum heat flux density increases.
{"title":"Optical Performance Analysis of Conical Cavity Receiver","authors":"Hu Xiao, Yanping Zhang, Chongzhe Zou","doi":"10.11159/ICERT19.116","DOIUrl":"https://doi.org/10.11159/ICERT19.116","url":null,"abstract":"In this paper, the commercial software TracePro was used to investigate the effects of some factors on a conical cavity receiver, such as the conical angle, the number of loops of the helical tube, and the distance between the focal point of the collector and the aperture. These factors affect the optical efficiency, the maximum heat flux density, and the light distribution in the conical cavity. The optical performance of the conical receiver was studied and analyzed using the Monte Carlo ray tracing method. The results showed that the amount of light rays reaching the helical tube increases with the increasing of the conical angle, while the optical efficiency decreases and the maximum heat flux density increases.","PeriodicalId":265434,"journal":{"name":"Proceedings of the 5th World Congress on New Technologies","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127133999","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":"Proof-Of-Principle Experiments for Phz Nano-Device Using Semi-Metallization of Dielectrics under Strong Optical Fields","authors":"D. Kim","doi":"10.11159/ICNFA19.150","DOIUrl":"https://doi.org/10.11159/ICNFA19.150","url":null,"abstract":"","PeriodicalId":265434,"journal":{"name":"Proceedings of the 5th World Congress on New Technologies","volume":"93 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127327624","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}
The paper assesses the presence of metals in soils around automobile workshops in Ilorin Nigeria. Automobiles workshops are becoming points of pollution concerns to the environments. Core samples were obtained from five automobile workshops site at a different part of the city. Hand auger was used in obtaining the samples. Both the contaminated topsoil and uncontaminated subsoil section was obtained. Majors and trace metals were analysed for the soil samples using XRF machines. Soil mineralogical composition was analysed using XRD. Other analyses carried out on the soil samples are soil pH and grain sizes composition. Results show the compositions of major oxides are silica, alumina and iron oxides while minors composition include potassium, sodium and manganese oxides. Zinc, arsenic and vanadium are the major trace metals contaminants in the soil. Soil pH shows a slightly acidic to neutral. Sources of trace metals in the soils of automobiles workshop are worn-out parts, metal craps, zinc paints, steel alloys in crankshaft and gears and packaging materials. The assessment has shown that automobile workshops introduces heavy metals pollutions into soils and they are a major source of environmental pollution.
{"title":"Assessment of Metals in Soils around Automobile Workshops in Ilorin NC, Nigeria","authors":"S. Oke, F. McIver","doi":"10.11159/ICEPR19.181","DOIUrl":"https://doi.org/10.11159/ICEPR19.181","url":null,"abstract":"The paper assesses the presence of metals in soils around automobile workshops in Ilorin Nigeria. Automobiles workshops are becoming points of pollution concerns to the environments. Core samples were obtained from five automobile workshops site at a different part of the city. Hand auger was used in obtaining the samples. Both the contaminated topsoil and uncontaminated subsoil section was obtained. Majors and trace metals were analysed for the soil samples using XRF machines. Soil mineralogical composition was analysed using XRD. Other analyses carried out on the soil samples are soil pH and grain sizes composition. Results show the compositions of major oxides are silica, alumina and iron oxides while minors composition include potassium, sodium and manganese oxides. Zinc, arsenic and vanadium are the major trace metals contaminants in the soil. Soil pH shows a slightly acidic to neutral. Sources of trace metals in the soils of automobiles workshop are worn-out parts, metal craps, zinc paints, steel alloys in crankshaft and gears and packaging materials. The assessment has shown that automobile workshops introduces heavy metals pollutions into soils and they are a major source of environmental pollution.","PeriodicalId":265434,"journal":{"name":"Proceedings of the 5th World Congress on New Technologies","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129407702","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}
Abdalrahman Alsulaili, Wasan Alkhamees, Saada Alghurbah, A. AlMershed, S. Alrashdan
The soil pollution issue in Kuwait was a result of the burning of the oil wells during the 1990 Gulf War. The contaminated soil’s consequences have become more dangerous in many aspects, such as groundwater, dust action, human and animal’s health. In this research, a bio-remediating technology known as the vermi-remediation was chosen to treat the oil contaminated soil by using of earthworms. The objective of this project is to conduct a series of experiments to conclude whether this technique is effective in treating Kuwait’s soil and to what extent. The treatment results were found to surpass the results of the currently being implemented methods by both contamination percentage drops and time of treatment. The system was found to treat up to 62% in the TPH level for highly oilcontaminated soil samples, 55% for medium oil-contaminated soil samples and 71% for low oil-contaminated soil samples within three
{"title":"Bioremediation to Treat the World’s Worst Ever Recorded Oil Contamination Case","authors":"Abdalrahman Alsulaili, Wasan Alkhamees, Saada Alghurbah, A. AlMershed, S. Alrashdan","doi":"10.11159/ICEPR19.154","DOIUrl":"https://doi.org/10.11159/ICEPR19.154","url":null,"abstract":"The soil pollution issue in Kuwait was a result of the burning of the oil wells during the 1990 Gulf War. The contaminated soil’s consequences have become more dangerous in many aspects, such as groundwater, dust action, human and animal’s health. In this research, a bio-remediating technology known as the vermi-remediation was chosen to treat the oil contaminated soil by using of earthworms. The objective of this project is to conduct a series of experiments to conclude whether this technique is effective in treating Kuwait’s soil and to what extent. The treatment results were found to surpass the results of the currently being implemented methods by both contamination percentage drops and time of treatment. The system was found to treat up to 62% in the TPH level for highly oilcontaminated soil samples, 55% for medium oil-contaminated soil samples and 71% for low oil-contaminated soil samples within three","PeriodicalId":265434,"journal":{"name":"Proceedings of the 5th World Congress on New Technologies","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130991195","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}
Extended Abstract Two-dimensional electron gas (2DEG) at an epitaxial interface of LaAlO3/SrTiO3 (LAO/STO) heterostructures has received considerable attentions because of their unique physical properties.[1] Electrons at the interface of LAO/STO heterostructure move freely along in-plane direction while they are confined in 1~2 nm range of out-of-plane direction. The electron density of 2DEG at LAO/STO heterostructure is 10~10/cm which is 100 times higher than those of the conventional semiconductor heterojunction such as AlGaAs/GaAs. The high density of electrons enables a fabrication of high-performance transistor. Unfortunately, the growth of LAO epitaxial layer on single crystalline STO substrate is necessary for 2DEG generation via polar catastrophe mechanism which impeded a practical use of the oxide heterostructure. Here, we demonstrated a creation of 2DEG at the non-epitaxial interface of Al2O3/TiO2 (<15 nm) thin film heterostructure via atomic layer deposition (ALD), without using single crystalline STO substrate for the first time.[2] By implementing ALD, the mature thin film process can facilitate mass production as well as three-dimensional integration of the devices. The electrical properties of thin film Al2O3/TiO2 heterostructure are similar with those of the epitaxial LAO/STO heterostructures. It was observed that high density electrons up to (10~10/cm) were confined within ~2.2 nm of the interface of the Al2O3/TiO2 heterostructure. Interestingly, the electron density can be adjusted from ~ 10/cm to ~ 10/cm by the control of ALD process temperature because the free electrons are created by the formation of oxygen vacancies at the interface of Al2O3/TiO2 heterostructure of which kinetics is governed by the ALD process temperature. Those oxides (Al2O3 and TiO2) are transparent insulators with wide bandgaps (>3.2 eV) which implies a possible application of transparent devices. With the Al2O3/TiO2 thin film heterostructure, a transparent thin film transistor (TFT) was fabricated which outperforms conventional TFTs. A high on-current (Ion, > 12 A/m), high on/off current ratio (Ion/Ioff > ~10), low off-current (Ioff, ~10 8 A/m), and low sub-threshold swing (SS, ~100 mV/dec.) are achieved. Besides the TFT application, a high-performance transparent hydrogen (H2) gas sensor was developed using the 2DEG at Al2O3/TiO2 thin film heterostructure which shows a sensitive detection of H2 gas even at room temperature.[3] It exhibited a reliable detection with a fast response speed (<30 s) for H2 concentration as low as 5 ppm which outperforms conventional H2 gas sensors operating at room temperature, indicating that heating modules are not required for the rapid detection of H2. The gas sensor can detect H2 gas across a wide range of concentrations, from 5 ppm to 1%, implying that it is a promising candidate for a general H2 sensor. The H2 gas sensor using 2DEG was fabricated on a polyimide substrate which enabled a fabrication of flexible g
{"title":"Transistor Using Two-dimensional Electron Gas in Thin Film Oxide Heterostructure via Atomic Layer Deposition","authors":"Hye Ju Kim, S. H. Kim, Sang Woon Lee","doi":"10.11159/ICNFA19.134","DOIUrl":"https://doi.org/10.11159/ICNFA19.134","url":null,"abstract":"Extended Abstract Two-dimensional electron gas (2DEG) at an epitaxial interface of LaAlO3/SrTiO3 (LAO/STO) heterostructures has received considerable attentions because of their unique physical properties.[1] Electrons at the interface of LAO/STO heterostructure move freely along in-plane direction while they are confined in 1~2 nm range of out-of-plane direction. The electron density of 2DEG at LAO/STO heterostructure is 10~10/cm which is 100 times higher than those of the conventional semiconductor heterojunction such as AlGaAs/GaAs. The high density of electrons enables a fabrication of high-performance transistor. Unfortunately, the growth of LAO epitaxial layer on single crystalline STO substrate is necessary for 2DEG generation via polar catastrophe mechanism which impeded a practical use of the oxide heterostructure. Here, we demonstrated a creation of 2DEG at the non-epitaxial interface of Al2O3/TiO2 (<15 nm) thin film heterostructure via atomic layer deposition (ALD), without using single crystalline STO substrate for the first time.[2] By implementing ALD, the mature thin film process can facilitate mass production as well as three-dimensional integration of the devices. The electrical properties of thin film Al2O3/TiO2 heterostructure are similar with those of the epitaxial LAO/STO heterostructures. It was observed that high density electrons up to (10~10/cm) were confined within ~2.2 nm of the interface of the Al2O3/TiO2 heterostructure. Interestingly, the electron density can be adjusted from ~ 10/cm to ~ 10/cm by the control of ALD process temperature because the free electrons are created by the formation of oxygen vacancies at the interface of Al2O3/TiO2 heterostructure of which kinetics is governed by the ALD process temperature. Those oxides (Al2O3 and TiO2) are transparent insulators with wide bandgaps (>3.2 eV) which implies a possible application of transparent devices. With the Al2O3/TiO2 thin film heterostructure, a transparent thin film transistor (TFT) was fabricated which outperforms conventional TFTs. A high on-current (Ion, > 12 A/m), high on/off current ratio (Ion/Ioff > ~10), low off-current (Ioff, ~10 8 A/m), and low sub-threshold swing (SS, ~100 mV/dec.) are achieved. Besides the TFT application, a high-performance transparent hydrogen (H2) gas sensor was developed using the 2DEG at Al2O3/TiO2 thin film heterostructure which shows a sensitive detection of H2 gas even at room temperature.[3] It exhibited a reliable detection with a fast response speed (<30 s) for H2 concentration as low as 5 ppm which outperforms conventional H2 gas sensors operating at room temperature, indicating that heating modules are not required for the rapid detection of H2. The gas sensor can detect H2 gas across a wide range of concentrations, from 5 ppm to 1%, implying that it is a promising candidate for a general H2 sensor. The H2 gas sensor using 2DEG was fabricated on a polyimide substrate which enabled a fabrication of flexible g","PeriodicalId":265434,"journal":{"name":"Proceedings of the 5th World Congress on New Technologies","volume":"111 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125869244","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}
The commitment for sustainability is a target for the Sustainable Universities Network. Sapienza University of Rome goes in this direction through the energy refurbishment of its building stock, i.e. all the educational buildings. Sapienza campus was built in the 30’s and it needs a coherent improvement in terms of energy and environmental performance. Conventional energy retrofitting measures must be within a prioritazion framework to effectively take the most cost-effective strategy. Here, the case of the Chemistry Faculty building is analysed considering the improvement of the building envelope in compliance with the architectural values to be preserved as well as the integration of renewable energy plant. A model of building was used to study it and to create the scenarios and their architectural impact. Furthermore, an energy analysis of the designed refurbishment was carried out to identify the savings.
{"title":"Energy Savings in an University Educational Building – The Case Of Chemistry Building Of Sapienza","authors":"F. Pini, Sara Verzari, A. D’Angelo","doi":"10.11159/ICERT19.123","DOIUrl":"https://doi.org/10.11159/ICERT19.123","url":null,"abstract":"The commitment for sustainability is a target for the Sustainable Universities Network. Sapienza University of Rome goes in this direction through the energy refurbishment of its building stock, i.e. all the educational buildings. Sapienza campus was built in the 30’s and it needs a coherent improvement in terms of energy and environmental performance. Conventional energy retrofitting measures must be within a prioritazion framework to effectively take the most cost-effective strategy. Here, the case of the Chemistry Faculty building is analysed considering the improvement of the building envelope in compliance with the architectural values to be preserved as well as the integration of renewable energy plant. A model of building was used to study it and to create the scenarios and their architectural impact. Furthermore, an energy analysis of the designed refurbishment was carried out to identify the savings.","PeriodicalId":265434,"journal":{"name":"Proceedings of the 5th World Congress on New Technologies","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121894386","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：