Maximum aerobic capacity is the most important parameter of cardiopulmonary fitness and an independent parameter for cardiovascular and respiratory disease prognosis. Prediction equations for varies with age, gender, body size, level of ordinary activity, type of exercise and races. Those equations have never been studied in Thais. This study aimed to provide prediction equations for in Thai males and females and to evaluate associations between age, weight and height, and . The maximum aerobic capacity was analysed in 44 healthy Thai subjects (20 males and 24 females; aged 20 – 50 years) who underwent cardiopulmonary exercise testing (CPET) using a treadmill and an incremental protocol until symptom limitation. All subjects had normal ranges of clinical characteristics and pulmonary function except those of weight and height in males were higher than in females (p<0.001) while age in males was lower than in females (p<0.05). Predictive equations for were obtained from multiple linear regression analysis and significant correlations demonstrated a negative correlation between and age (p<0.05), and positive correlations between and weight and height (p<0.001). The prediction equation: = 3222.9 + (792.4 * sex) + (-11.3 * age) + (21.0 * weight) + (-15.7 * height) (R 2 = 0.72, SEE=308.5 ml/min) (1 = male, 0 = female; age in years (yr); weight in kilograms (kg); height in centimeters (cm)). In addition, in males was significantly higher than in females by 59% (p<0.001). The present study provides the prediction equation for applicable to the Thai population. Nonetheless, it is compulsory to have more sets of normal values to be accumulated so that reference values can be established in the future. We also demonstrate that males have higher than those of females.
{"title":"Prediction Equations for Maximum Aerobic Capacity Using Cardiopulmonary Exercise Testing Among Thais","authors":"et.al Tichanon Promsrisuk","doi":"10.14456/KKURJ.2015.37","DOIUrl":"https://doi.org/10.14456/KKURJ.2015.37","url":null,"abstract":"Maximum aerobic capacity is the most important parameter of cardiopulmonary fitness and an independent parameter for cardiovascular and respiratory disease prognosis. Prediction equations for varies with age, gender, body size, level of ordinary activity, type of exercise and races. Those equations have never been studied in Thais. This study aimed to provide prediction equations for in Thai males and females and to evaluate associations between age, weight and height, and . The maximum aerobic capacity was analysed in 44 healthy Thai subjects (20 males and 24 females; aged 20 – 50 years) who underwent cardiopulmonary exercise testing (CPET) using a treadmill and an incremental protocol until symptom limitation. All subjects had normal ranges of clinical characteristics and pulmonary function except those of weight and height in males were higher than in females (p<0.001) while age in males was lower than in females (p<0.05). Predictive equations for were obtained from multiple linear regression analysis and significant correlations demonstrated a negative correlation between and age (p<0.05), and positive correlations between and weight and height (p<0.001). The prediction equation: = 3222.9 + (792.4 * sex) + (-11.3 * age) + (21.0 * weight) + (-15.7 * height) (R 2 = 0.72, SEE=308.5 ml/min) (1 = male, 0 = female; age in years (yr); weight in kilograms (kg); height in centimeters (cm)). In addition, in males was significantly higher than in females by 59% (p<0.001). The present study provides the prediction equation for applicable to the Thai population. Nonetheless, it is compulsory to have more sets of normal values to be accumulated so that reference values can be established in the future. We also demonstrate that males have higher than those of females.","PeriodicalId":8597,"journal":{"name":"Asia-Pacific Journal of Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2015-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66675883","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}
This work present the experimental investigation on heat transfer enhancement and thermal performance in a square-duct heat exchanger inserted with 45o V-downstream winglet turbulator is carried out by varying velocity of air in the turbulent regime for Reynolds numbers (Re) ranging from 4000 to 26,000 in the test section with a constant wall heat flux condition. Influents of four different pitch lengths; P=22.5, 33.75, 45 and 90 mm (PR=P/H=0.5, 0.75, 1 and 2) and three different winglet heights, e=6.75, 9 and 11.25 mm (BR=e/H=0.15, 0.2 and 0.25) were inserted diagonally and placed in the core flow area into the test duct on heat transfer rates in the term of Nusselt number (Nu), pressure loss in form of friction factor (f) and thermal performance (). It was found that the 45o V-downstream winglet is provided the Nu and f higher than the smooth surface around 6.0 to 8.7 times and 37 to 170 times, respectively depending upon operating conditions while the thermal performance are about 1.50–2.06. The maximum thermal performance for using 45o V-downstream winglet turbulator is 2.06 at Re=4100, BR=0.2 and PR=1.0 in this experiment.
本文在恒定壁面热流密度条件下，在雷诺数(Re)为4000 ~ 26000的紊流状态下，对插入45o v下游小翼紊流器的方形管换热器进行了换热强化和热性能的实验研究。四种不同节距的影响;将P=22.5、33.75、45和90 mm (PR=P/H=0.5、0.75、1和2)和3个不同小翼高度e=6.75、9和11.25 mm (BR=e/H=0.15、0.2和0.25)对角插入，放置在核心流道内，观察以努塞尔数(Nu)表示的换热率、以摩擦系数(f)表示的压力损失和热性能(f)。结果表明，45o v下游小翼在不同工况下Nu和f分别比光滑表面高6.0 ~ 8.7倍和37 ~ 170倍，热性能约为1.50 ~ 2.06。在Re=4100, BR=0.2, PR=1.0条件下，采用45o v下游小翼紊流器的最大热性能为2.06。
{"title":"Heat transfer and fluid flow behavior of air in square duct heat exchanger inserted with v-downstream winglet turbulators","authors":"et.al Suriya Chokphoemphun","doi":"10.14456/KKURJ.2015.33","DOIUrl":"https://doi.org/10.14456/KKURJ.2015.33","url":null,"abstract":"This work present the experimental investigation on heat transfer enhancement and thermal performance in a square-duct heat exchanger inserted with 45o V-downstream winglet turbulator is carried out by varying velocity of air in the turbulent regime for Reynolds numbers (Re) ranging from 4000 to 26,000 in the test section with a constant wall heat flux condition. Influents of four different pitch lengths; P=22.5, 33.75, 45 and 90 mm (PR=P/H=0.5, 0.75, 1 and 2) and three different winglet heights, e=6.75, 9 and 11.25 mm (BR=e/H=0.15, 0.2 and 0.25) were inserted diagonally and placed in the core flow area into the test duct on heat transfer rates in the term of Nusselt number (Nu), pressure loss in form of friction factor (f) and thermal performance (). It was found that the 45o V-downstream winglet is provided the Nu and f higher than the smooth surface around 6.0 to 8.7 times and 37 to 170 times, respectively depending upon operating conditions while the thermal performance are about 1.50–2.06. The maximum thermal performance for using 45o V-downstream winglet turbulator is 2.06 at Re=4100, BR=0.2 and PR=1.0 in this experiment.","PeriodicalId":8597,"journal":{"name":"Asia-Pacific Journal of Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2015-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66675828","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}
Precipitation hardening process is important to increase the hardness of 6061 aluminium alloy. In order to achieve the desired hardness, this process has several controlled parameters including solution soaking temperature, solution soaking time, aging temperature and aging time. The identification of each appropriate parameter is important in the precipitation hardening process of aluminium alloy. Because there has been no method or exact pattern, therefore this research work applies the response surface methodology with Box-Behnken design to determine these appropriate parameters. The experimental result is found that there are three factors significantly affecting on the hardness obtained from the precipitation hardening process. The experimental data is well fit a quadratic model due to high coefficient of determination (R2=0.92). When this regression model is taken to construct the three-dimensional surface response plot and the contour plot, it is found that the optimum condition is the solution treatment time of 5 hours and 18 minutes, aging temperature of 181C and the aging time of 10 hours which yield the maximum predicted Vicker hardness of 132.5 HV.
{"title":"Optimal Parameters in Precipitation Hardening of 6061 Aluminium Alloy Using Box-Behnken Design","authors":"Somsak Kaewploy","doi":"10.14456/KKURJ.2015.31","DOIUrl":"https://doi.org/10.14456/KKURJ.2015.31","url":null,"abstract":"Precipitation hardening process is important to increase the hardness of 6061 aluminium alloy. In order to achieve the desired hardness, this process has several controlled parameters including solution soaking temperature, solution soaking time, aging temperature and aging time. The identification of each appropriate parameter is important in the precipitation hardening process of aluminium alloy. Because there has been no method or exact pattern, therefore this research work applies the response surface methodology with Box-Behnken design to determine these appropriate parameters. The experimental result is found that there are three factors significantly affecting on the hardness obtained from the precipitation hardening process. The experimental data is well fit a quadratic model due to high coefficient of determination (R2=0.92). When this regression model is taken to construct the three-dimensional surface response plot and the contour plot, it is found that the optimum condition is the solution treatment time of 5 hours and 18 minutes, aging temperature of 181C and the aging time of 10 hours which yield the maximum predicted Vicker hardness of 132.5 HV.","PeriodicalId":8597,"journal":{"name":"Asia-Pacific Journal of Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2015-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66675810","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}
Aim: The majority of Thai SSc patients represent a unique ethnic group found in Northeastern Thailand. Genetic susceptibility may be found in the pathogenesis of Thai SSc patients. This study aims to identify HLA genes which correlate with clinical profiles in these SSc patients. Methods : Peripheral blood samples were taken from 60 SSc patients diagnosed using the ACR classification 1980 criteria. HLA-A, -B, and -C were analyzed using the PCR-amplification refractory mutation system, and the PCR-sequence specific primer was used for the HLA-DR and- DQ analysis. The distribution of the alleles between SSc patients and the control was found to be significant when it was tested with the corrected P value (<0.05). Results : Of the 60 SSc patients examined; 66.7% displayed symptoms of diffuse cutaneous SSc (dcSSc), and 33.3% showed limited cutaneous SSc (lcSSc). In the Thai SSc group, the prevalence of HLA DRB1*1502 (allele frequency: AF = 32.5%) and DQB1*0501 (AF = 30.8%) which was significantly higher when compared to the control group (AF = 18.5% and 16.3%) with corrected P value (Pc) = 0.0007 and 0.0001, respectively. Conclusions : The majority of Thai SSc patients that actually displayed dcSSc, had a high prevalence of internal organ involvement. The results suggest a genetic susceptibility for SSc among the population of Northeastern Thailand, especially for individuals with HLA DRB1*1502. In the West, there is less HLA DRB1*1502, and this factor could explain why dcSSc is more prevalent among the Thai population.
{"title":"The association of HLA and systemic sclerosis (SSc) in the northeastern Thais.","authors":"A. Mahakkanukrauh","doi":"10.14456/kkurj.2015.38","DOIUrl":"https://doi.org/10.14456/kkurj.2015.38","url":null,"abstract":"Aim: The majority of Thai SSc patients represent a unique ethnic group found in Northeastern Thailand. Genetic susceptibility may be found in the pathogenesis of Thai SSc patients. This study aims to identify HLA genes which correlate with clinical profiles in these SSc patients. Methods : Peripheral blood samples were taken from 60 SSc patients diagnosed using the ACR classification 1980 criteria. HLA-A, -B, and -C were analyzed using the PCR-amplification refractory mutation system, and the PCR-sequence specific primer was used for the HLA-DR and- DQ analysis. The distribution of the alleles between SSc patients and the control was found to be significant when it was tested with the corrected P value (<0.05). Results : Of the 60 SSc patients examined; 66.7% displayed symptoms of diffuse cutaneous SSc (dcSSc), and 33.3% showed limited cutaneous SSc (lcSSc). In the Thai SSc group, the prevalence of HLA DRB1*1502 (allele frequency: AF = 32.5%) and DQB1*0501 (AF = 30.8%) which was significantly higher when compared to the control group (AF = 18.5% and 16.3%) with corrected P value (Pc) = 0.0007 and 0.0001, respectively. Conclusions : The majority of Thai SSc patients that actually displayed dcSSc, had a high prevalence of internal organ involvement. The results suggest a genetic susceptibility for SSc among the population of Northeastern Thailand, especially for individuals with HLA DRB1*1502. In the West, there is less HLA DRB1*1502, and this factor could explain why dcSSc is more prevalent among the Thai population.","PeriodicalId":8597,"journal":{"name":"Asia-Pacific Journal of Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2015-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66675892","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}
Treatment-based and movement system impairment-based classifications have been widely used to identify movement control impairment (MCI) in patients with non-specific low back pain. Clinical observation of aberrant movement patterns is an essential aspect of the examination to identify patients with MCI. The treatment of these patients is a therapeutic exercise that involves static and dynamic stability of core stabilizing muscles. Although exercise prescriptions for these patients are similar, intervention may vary based upon its concept. Interventions include the core stabilization exercise (CSE) approach based upon stabilizing system model, and movement system impairment (MSI) approach based upon kinesiopathologic model. CSE focuses on neuromuscular function to compensate for impairment of intervertebral disc and joints, whereas MSI emphasizes movement correction and enhances movement efficiency to prevent injury and impairment. Both approaches seem equally effective in reducing pain and disability for the MCI group. Therefore, clinicians can utilize either approach for rehabilitating patients with MCI. However, if differences in effectiveness are found when utilizing these different approaches we should explore if the MCI classification needs further definition. In addition, further study needs to investigate the underlying mechanisms in patients with MCI, and the ability of each approach to change those mechanisms.
{"title":"Core Stabilization Exercise and Movement System Impairment Approaches for Patients with Movement Control Impairment: A Review Article","authors":"Peemongkon Wattananona","doi":"10.14456/KKURJ.2015.40","DOIUrl":"https://doi.org/10.14456/KKURJ.2015.40","url":null,"abstract":"Treatment-based and movement system impairment-based classifications have been widely used to identify movement control impairment (MCI) in patients with non-specific low back pain. Clinical observation of aberrant movement patterns is an essential aspect of the examination to identify patients with MCI. The treatment of these patients is a therapeutic exercise that involves static and dynamic stability of core stabilizing muscles. Although exercise prescriptions for these patients are similar, intervention may vary based upon its concept. Interventions include the core stabilization exercise (CSE) approach based upon stabilizing system model, and movement system impairment (MSI) approach based upon kinesiopathologic model. CSE focuses on neuromuscular function to compensate for impairment of intervertebral disc and joints, whereas MSI emphasizes movement correction and enhances movement efficiency to prevent injury and impairment. Both approaches seem equally effective in reducing pain and disability for the MCI group. Therefore, clinicians can utilize either approach for rehabilitating patients with MCI. However, if differences in effectiveness are found when utilizing these different approaches we should explore if the MCI classification needs further definition. In addition, further study needs to investigate the underlying mechanisms in patients with MCI, and the ability of each approach to change those mechanisms.","PeriodicalId":8597,"journal":{"name":"Asia-Pacific Journal of Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2015-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66675931","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}
Dragon fruit [ Hylocereus undatus (Haworth) Britton & Rose] grown in Loei province is one of dragon fruit cultivars with high quality and rich of sweetness compared to the fruits from other areas. There were some fungal infections observed in post-harvested diseases caused serious damage on the fruits leading to serious damages to the produces. Therefore, Fungi were isolated from three infected parts of the plants e.g. stems, flowers and fruits, in relevant to the causative pathogens. Two fungal species, Alternaria sp . and Phomopsis sp . were found on the stems. Six species, Bipolaris cactivora , Cladosporium cucumerinum , Fusarium sp . , Alternaria sp . and Colletotrichum gloeosporiodes were obtained from rotten flowers. From the fruits, three fungi, B. cactivora , C. gloeosporiodes and Rhizopus stolonifer were isolated . The most frequently species isolated from the fruits was B. cactivora was the most frequently isolates from the fruits and some epidemiological aspects of the pathogen were studied in details.
{"title":"Fungi on dragon fruit in Loei province, Thailand and the ability of bipolaris cactivora to cause post-harvest fruit rot","authors":"et.al Samoul Oeurn","doi":"10.14456/KKURJ.2015.34","DOIUrl":"https://doi.org/10.14456/KKURJ.2015.34","url":null,"abstract":"Dragon fruit [ Hylocereus undatus (Haworth) Britton & Rose] grown in Loei province is one of dragon fruit cultivars with high quality and rich of sweetness compared to the fruits from other areas. There were some fungal infections observed in post-harvested diseases caused serious damage on the fruits leading to serious damages to the produces. Therefore, Fungi were isolated from three infected parts of the plants e.g. stems, flowers and fruits, in relevant to the causative pathogens. Two fungal species, Alternaria sp . and Phomopsis sp . were found on the stems. Six species, Bipolaris cactivora , Cladosporium cucumerinum , Fusarium sp . , Alternaria sp . and Colletotrichum gloeosporiodes were obtained from rotten flowers. From the fruits, three fungi, B. cactivora , C. gloeosporiodes and Rhizopus stolonifer were isolated . The most frequently species isolated from the fruits was B. cactivora was the most frequently isolates from the fruits and some epidemiological aspects of the pathogen were studied in details.","PeriodicalId":8597,"journal":{"name":"Asia-Pacific Journal of Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2015-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66675842","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}
Strength of granite under elevated temperatures is an important parameter governing the long-term stability of waste disposal boreholes. The objective of this study is to experimentally determine the effects of elevated temperatures on the compressive strengths and elasticity of Tak granite. The rock strength and deformability are determined under various temperatures and confining pressures. The confining stresses are maintained constant at 0, 3, 7, to 12 MPa using a polyaxial load frame. The rectangular block specimens have nominal dimensions of 5×5×10 cm3. The testing temperatures are varied from 273 to 773 Kelvin. The results indicate that the granite strength and elasticity exponentially decrease as the temperature increases. The distortional strain energy criterion is proposed to describe the rock strengths as a function of mean strain energy. The criterion fits well to the test results. The proposed strength criterion is useful to predict the strength and deformation of granite around waste disposal boreholes under elevated temperatures.
{"title":"Effects of temperatures on strength and deformability of Tak granite","authors":"et.al Kittikron Rodklang","doi":"10.14456/KKURJ.2015.22","DOIUrl":"https://doi.org/10.14456/KKURJ.2015.22","url":null,"abstract":"Strength of granite under elevated temperatures is an important parameter governing the long-term stability of waste disposal boreholes. The objective of this study is to experimentally determine the effects of elevated temperatures on the compressive strengths and elasticity of Tak granite. The rock strength and deformability are determined under various temperatures and confining pressures. The confining stresses are maintained constant at 0, 3, 7, to 12 MPa using a polyaxial load frame. The rectangular block specimens have nominal dimensions of 5×5×10 cm3. The testing temperatures are varied from 273 to 773 Kelvin. The results indicate that the granite strength and elasticity exponentially decrease as the temperature increases. The distortional strain energy criterion is proposed to describe the rock strengths as a function of mean strain energy. The criterion fits well to the test results. The proposed strength criterion is useful to predict the strength and deformation of granite around waste disposal boreholes under elevated temperatures.","PeriodicalId":8597,"journal":{"name":"Asia-Pacific Journal of Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2015-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66675610","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 work, CaCu3Ti4.7O12 (CCT4.7O) powder was prepared by polymer pyrolysis method. The influence of phase composition and microstructure were characterized using X ray diffraction (XRD) and scanning electron microscopy (SEM). The results show that the TiO2 secondary phase has a remarkable on the microstructure, dielectric loss tangent (tan and dielectric constant () of CCT4.7O ceramics, respectively. Interestingly, low loss tangent of ~0.03 and giant dielectric constant of 31,908 with temperature coefficients less than ±15% in the temperature range of −50–90 oC are observed in a ceramic sintered at 1060 oC for 10h (CCT4.7O-2). Both of ceramics sintered at 1060 oC for 6h (CCT4.7O-1) and 10 h (CCT4.7O-2) display a non linear current voltage with the non-linear coefficient () and breakdown field (Eb) values of 6.4, 5.6 and 1554, 1020, respectively. The dielectric constant, electrical response of grain boundaries, and related nonlinear currentvoltage behavior are found to be associated with the microstructure of CCT4.7O ceramics.
{"title":"Giant dielectric, low loss tangent and non-ohmics properties of CaCu3Ti4.7O12 ceramics prepared by polymer pyrolysis method","authors":"et.al Sunan Nonglek","doi":"10.14456/KKURJ.2015.29","DOIUrl":"https://doi.org/10.14456/KKURJ.2015.29","url":null,"abstract":"In this work, CaCu3Ti4.7O12 (CCT4.7O) powder was prepared by polymer pyrolysis method. The influence of phase composition and microstructure were characterized using X ray diffraction (XRD) and scanning electron microscopy (SEM). The results show that the TiO2 secondary phase has a remarkable on the microstructure, dielectric loss tangent (tan and dielectric constant () of CCT4.7O ceramics, respectively. Interestingly, low loss tangent of ~0.03 and giant dielectric constant of 31,908 with temperature coefficients less than ±15% in the temperature range of −50–90 oC are observed in a ceramic sintered at 1060 oC for 10h (CCT4.7O-2). Both of ceramics sintered at 1060 oC for 6h (CCT4.7O-1) and 10 h (CCT4.7O-2) display a non linear current voltage with the non-linear coefficient () and breakdown field (Eb) values of 6.4, 5.6 and 1554, 1020, respectively. The dielectric constant, electrical response of grain boundaries, and related nonlinear currentvoltage behavior are found to be associated with the microstructure of CCT4.7O ceramics.","PeriodicalId":8597,"journal":{"name":"Asia-Pacific Journal of Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2015-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66675701","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}
This paper considers the discrete time surplus process in the case of fire insurance given by U_0=u,U_n=U_(n-1)+cZ_n-Y_n, where {Y_n,n≥1} is the claim severity process, {Z_n,n≥1} is the inter-arrival process, c is the premium rate, and U_0=u≥0 is the initial capital. The claim severities and the inter-arrival time are provided by the Thai Reinsurance Public Co., Ltd. In addition, we assume that {Y_n,n≥1} and {Z_n,n≥1} are independent and identically distributed, Y_n has Weibull distribution and Z_n has Poisson distribution. By using the maximum likelihood estimator method, we find that〖 Y〗_n~Weibull(0.8484,30.5396) and Z_n~Poisson(37.8958). Finally, we approximate the finite-time ruin probability for one year by a simulation approach, and use the logarithmic regression to approximate the minimum initial capital corresponding to the quantities of risk α=0.01 and 0.05, respectively.
{"title":"On approximating the minimum initial capital of fire insurance with the finite-time ruin probability using a simulation approach","authors":"et.al Supawan Khotama","doi":"10.14456/KKURJ.2015.21","DOIUrl":"https://doi.org/10.14456/KKURJ.2015.21","url":null,"abstract":"This paper considers the discrete time surplus process in the case of fire insurance given by U_0=u,U_n=U_(n-1)+cZ_n-Y_n, where {Y_n,n≥1} is the claim severity process, {Z_n,n≥1} is the inter-arrival process, c is the premium rate, and U_0=u≥0 is the initial capital. The claim severities and the inter-arrival time are provided by the Thai Reinsurance Public Co., Ltd. In addition, we assume that {Y_n,n≥1} and {Z_n,n≥1} are independent and identically distributed, Y_n has Weibull distribution and Z_n has Poisson distribution. By using the maximum likelihood estimator method, we find that〖 Y〗_n~Weibull(0.8484,30.5396) and Z_n~Poisson(37.8958). Finally, we approximate the finite-time ruin probability for one year by a simulation approach, and use the logarithmic regression to approximate the minimum initial capital corresponding to the quantities of risk α=0.01 and 0.05, respectively.","PeriodicalId":8597,"journal":{"name":"Asia-Pacific Journal of Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2015-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66676052","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 structural and optical properties of hydrogen-terminated silicon quantum dots were investigated by using the Gaussian 09 program. The models of silicon quantum dots assume that the silicon atoms are covalently bonded in diamond crystal structure, with quantum dot diameters varying from 0.8 to 1.6 nanometers. The bonds of silicon atoms at the surface were terminated by hydrogen atoms. The calculations of optimized structures and ground state electronic properties for the quantum dots have been performed using Hartree-Fock with 6-31G* basis set, and the exited states were then calculated by using time-dependent density functional theory (TDDFT) with (B3LYP) hybrid functional. The results show that the hydrogen-terminated silicon quantum dots have tuneable absorption energy, depending on particle size, and the larger particles have lower absorption energy. The calculated UV-VIS spectrum results show that with the quantum dots diameter changing from 0.8 nm to 1 nm to 1.2 nm the absorption peak moves from 5.23 eV (238 nm) to 4.68 eV (264 nm) to 4.03 eV (308 nm). Moreover, the hydrogen-capped silicon nanocrystals also show negative electron affinity (NEA).
利用高斯09程序研究了端氢硅量子点的结构和光学性质。硅量子点模型假设硅原子在金刚石晶体结构中共价结合，量子点直径在0.8 ~ 1.6纳米之间变化。表面硅原子的键被氢原子终止。采用6-31G*基集的Hartree-Fock方法计算了优化后的量子点结构和基态电子性质，并采用(B3LYP)混合泛函的时间依赖密度泛函理论(TDDFT)计算了量子点的激发态。结果表明，端氢硅量子点的吸收能随粒子大小的变化而变化，粒子越大，吸收能越低。计算的紫外可见光谱结果表明，当量子点直径从0.8 nm变化到1 nm到1.2 nm时，吸收峰从5.23 eV (238 nm)移动到4.68 eV (264 nm)到4.03 eV (308 nm)。此外，氢包覆的硅纳米晶体也表现出负电子亲和性(NEA)。
{"title":"Calculation of structural and optical properties of silicon quantum dots: tuneable absorption energy and negative electron affinity","authors":"et.al Ruhan Thirayathorn","doi":"10.14456/KKURJ.2015.23","DOIUrl":"https://doi.org/10.14456/KKURJ.2015.23","url":null,"abstract":"The structural and optical properties of hydrogen-terminated silicon quantum dots were investigated by using the Gaussian 09 program. The models of silicon quantum dots assume that the silicon atoms are covalently bonded in diamond crystal structure, with quantum dot diameters varying from 0.8 to 1.6 nanometers. The bonds of silicon atoms at the surface were terminated by hydrogen atoms. The calculations of optimized structures and ground state electronic properties for the quantum dots have been performed using Hartree-Fock with 6-31G* basis set, and the exited states were then calculated by using time-dependent density functional theory (TDDFT) with (B3LYP) hybrid functional. The results show that the hydrogen-terminated silicon quantum dots have tuneable absorption energy, depending on particle size, and the larger particles have lower absorption energy. The calculated UV-VIS spectrum results show that with the quantum dots diameter changing from 0.8 nm to 1 nm to 1.2 nm the absorption peak moves from 5.23 eV (238 nm) to 4.68 eV (264 nm) to 4.03 eV (308 nm). Moreover, the hydrogen-capped silicon nanocrystals also show negative electron affinity (NEA).","PeriodicalId":8597,"journal":{"name":"Asia-Pacific Journal of Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2015-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66675619","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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