对比分析API RP 5C5标准2017版和2003版对试样加工公差的要求,认为:API RP 5C5新、旧版标准中试样加工控制的关键参数主要为密封直径、螺纹中径、螺纹锥度等,螺纹锥度控制一致,密封直径、螺纹中径控制有区别;旧版强调螺纹直径和密封直...对比分析API RP 5C5标准2017版和2003版对试样加工公差的要求,认为:API RP 5C5新、旧版标准中试样加工控制的关键参数主要为密封直径、螺纹中径、螺纹锥度等,螺纹锥度控制一致,密封直径、螺纹中径控制有区别;旧版强调螺纹直径和密封直径偏差控制,而新版强调过盈量偏差控制;旧版有过盈量、低过盈量两种极限公差,而新版有极高过盈量、极低过盈量、过盈量、低过盈量四种极限公差;新版公差更苛刻,更合理,旧版公差为新版的特例.展开更多
A series of 2D model tests were conducted to assess the foundation stability of composite vertical breakwaters. In this paper, the results from the experimental study are presented conjointly with a formula to estimat...A series of 2D model tests were conducted to assess the foundation stability of composite vertical breakwaters. In this paper, the results from the experimental study are presented conjointly with a formula to estimate the stability number of foundation, which is the most important parameter for evaluation of foundation stability of such structures. The influences of wave height, wave period and the berm width on the stability of compo^ite breakwaters with different armor stone sizes were investigated. Forty-five tests were performed to cover the influences of these parameters. According to the present research, berm width is a significant parameter concerning erosion of armor foundation. As the berm width increases, the amount of berm erosion decreases. Comparisons are made between results of present study and the estimated stability number proposed by Kimura et al. （1994）, which is extension of Tanimoto formula. Results show that the later formula underestimates the stability number. However, by applying an enhancement factor about 1.7 meters to Kimura et al. formula, results correlated with the present experimental results..展开更多
The purpose of this work is the study of a mathematical model to discretize cracks at continuous mechanical systems, applying all the available properties at computational algorithm using the methodology of state obse...The purpose of this work is the study of a mathematical model to discretize cracks at continuous mechanical systems, applying all the available properties at computational algorithm using the methodology of state observers to detect, localize and evaluate the crack conditions, seeking the model limitations through an experiment developed at the mechanical department of UNESP, llha Solteira, S^o Paulo-Brazil. Three different notch sizes were placed, one by one, at the top surface of a cantilever beam （to be considered as a crack at the mechanical system） and harmonic forces were applied at the tip of the beam with three different frequencies, for each notch size, to obtain experimental data to run the diagnosis algorithm. From the results it was possible to infer that the observation system performance increases with the raising of the crack size, which can be explained by the model, that gets more accurate with bigger crack sizes, however, when the propagation of the crack is considered at the model, the diagnosis of the crack presence tends to be more difficult. It was also possible to conclude that the developed algorithm works properly for systems which excitation frequencies are higher than 20 Hz and different from the natural frequencies of the system, due to influence of dynamic response of the crack at the model.展开更多
Indian traditional sweet dish i.e. halwa was developed from pearl millet grains. Pearl millet grains （Pennisetum typhoides var. PHB-2168） were steamed for 20 min at 1.05 kg cm^2 in order to minimize lipase activity,...Indian traditional sweet dish i.e. halwa was developed from pearl millet grains. Pearl millet grains （Pennisetum typhoides var. PHB-2168） were steamed for 20 min at 1.05 kg cm^2 in order to minimize lipase activity, total phenols, phytic acid and tannins content. Steamed grains were dried （12 ± 0.5% moisture content）, pearled, milled, sieved through sieve opening size of 0.234 mm and were used for study. Central composite rotatable design （CCRD） with three independent variables i.e. vanaspati, sugar and water for rehydration were used to design the experiments. Sensory responses and rehydration ratio were used to study the individual and interactive effects of variables. Sensory score for colour varied from taste 6.3-7.9, mouth feel 6.4-7.8, overall acceptability （OAA） 6.5-7.9 and rehydration ratio （RR） from 1.4 to 2.3. All the responses fitted into quadratic equation with R2 〉 0.80. Halwa dry mix was also evaluated for stability in polyethylene pouches at ambient conditions and the peroxide and free fatty acids value were 21.35 meqO2 kg^-1 fat, 0.55% （oleic acid）, respectively after 6 months of storage. Based on compromise optimization, optimum levels of the ingredients recommended with 86.4% desirability were： vanaspati 38.6 g 100 g^-1 pearl millet semolina （PMS）, sugar 88.7 g 100 g^-1 PMS and water for rehydration 151 mL 100 g^-1 dry mix.展开更多
In this paper we present a performance evaluation of thermal spraying coated hot forging dies conducted in a production line. The High Velocity Oxy-Fuel process was used for the deposition of a tungsten carbide coatin...In this paper we present a performance evaluation of thermal spraying coated hot forging dies conducted in a production line. The High Velocity Oxy-Fuel process was used for the deposition of a tungsten carbide coating, which is characterized by its optimal adherence and low porosity. A metallurgical characterization of the layer was previously done, in order to obtain reference information to assist in the interpretation of the practical tests results. The coated die allowed an increase in productivity of 37.5%, besides better dimensional stability results through the process and legibility of printed numbers.展开更多
Road surface condition evaluation involves the collection of data over pavement surface for different types of distresses. The exercise consumes a lot of resources if the whole road section length is surveyed and may ...Road surface condition evaluation involves the collection of data over pavement surface for different types of distresses. The exercise consumes a lot of resources if the whole road section length is surveyed and may be prone to errors as a result of surveyors＇ fatigue. It is therefore important to develop a representative sample to be used when evaluating road condition manually. This study aimed at determining an adequate sample size for section level as well as a way forward for network level condition evaluation of highways in Nepal. Again the study was conducted to quantify the effects of altering the sample unit size for performing a distress survey according to the PCI （pavement condition index） and SDI （surface distress index） method separately for asphalt surfaced roads. The effect of reducing/increasing sample unit size was investigated adopting visual examination through field survey by eight teams in July, 2015, along the section of Banepa-Bardibas highway. The PCI was then calculated for each sample unit using standard deduct curves and PCI calculation methodology as per SHRP （Strategic Highway Research Program） recommendations and the computation of SDI was done as per DoR （Department of Roads） guidelines. The results show that 13% sample unit are needed for SDI and 21% for PCI computation, however, the results are out of the significant level. This is higher than DoR and SHRP guidelines. Again no strong relationship is observed between SDI and PCI values.展开更多
Finding alternative local sources of plant nutrients is a practical, low-cost, and long-term strategy. In this study, laboratory column experiments were conducted in a completely randomized design to evaluate the feas...Finding alternative local sources of plant nutrients is a practical, low-cost, and long-term strategy. In this study, laboratory column experiments were conducted in a completely randomized design to evaluate the feasibility of using phosphate rock and dolostone as fertilizers or acid-neutralizing agents for application in tropical acid soils. The dissolution rates of different particle-size fractions(0.063–0.25, 0.25–0.5, and 0.5–2 mm) of both rocks were studied by citric acid solution at p H 4 and 2 and water, with extraction times of 1, 3, 5, 7, 12, 24, 72, 144, 240, and 360 h. The results showed that the dissolution of both rocks depended on the particle size,leaching solution, and extraction time. The dissolution rate of rock-forming minerals increased as the specific surface area increased,corresponding to a decrease in particle size. In all cases, the release kinetics was characterized by two phases: 1) a first stage of rapid release that lasted 24 h and would ensure short-term nutrient release, and 2) a second stage of slow release after 24 h, representing the long-term nutrient release efficiency. Both rocks were suitable as slow-release fertilizers in strongly acid soils and would ensure the replenishment of P, Ca, and Mg. A combination of fine and medium particle-size fractions should be used to ensure high nutrient-release efficiency. Much work could remain to determine the overall impact of considerable amounts of fresh rocks in soils.展开更多
文摘对比分析API RP 5C5标准2017版和2003版对试样加工公差的要求,认为:API RP 5C5新、旧版标准中试样加工控制的关键参数主要为密封直径、螺纹中径、螺纹锥度等,螺纹锥度控制一致,密封直径、螺纹中径控制有区别;旧版强调螺纹直径和密封直径偏差控制,而新版强调过盈量偏差控制;旧版有过盈量、低过盈量两种极限公差,而新版有极高过盈量、极低过盈量、过盈量、低过盈量四种极限公差;新版公差更苛刻,更合理,旧版公差为新版的特例.
文摘A series of 2D model tests were conducted to assess the foundation stability of composite vertical breakwaters. In this paper, the results from the experimental study are presented conjointly with a formula to estimate the stability number of foundation, which is the most important parameter for evaluation of foundation stability of such structures. The influences of wave height, wave period and the berm width on the stability of compo^ite breakwaters with different armor stone sizes were investigated. Forty-five tests were performed to cover the influences of these parameters. According to the present research, berm width is a significant parameter concerning erosion of armor foundation. As the berm width increases, the amount of berm erosion decreases. Comparisons are made between results of present study and the estimated stability number proposed by Kimura et al. （1994）, which is extension of Tanimoto formula. Results show that the later formula underestimates the stability number. However, by applying an enhancement factor about 1.7 meters to Kimura et al. formula, results correlated with the present experimental results..
文摘The purpose of this work is the study of a mathematical model to discretize cracks at continuous mechanical systems, applying all the available properties at computational algorithm using the methodology of state observers to detect, localize and evaluate the crack conditions, seeking the model limitations through an experiment developed at the mechanical department of UNESP, llha Solteira, S^o Paulo-Brazil. Three different notch sizes were placed, one by one, at the top surface of a cantilever beam （to be considered as a crack at the mechanical system） and harmonic forces were applied at the tip of the beam with three different frequencies, for each notch size, to obtain experimental data to run the diagnosis algorithm. From the results it was possible to infer that the observation system performance increases with the raising of the crack size, which can be explained by the model, that gets more accurate with bigger crack sizes, however, when the propagation of the crack is considered at the model, the diagnosis of the crack presence tends to be more difficult. It was also possible to conclude that the developed algorithm works properly for systems which excitation frequencies are higher than 20 Hz and different from the natural frequencies of the system, due to influence of dynamic response of the crack at the model.
文摘Indian traditional sweet dish i.e. halwa was developed from pearl millet grains. Pearl millet grains （Pennisetum typhoides var. PHB-2168） were steamed for 20 min at 1.05 kg cm^2 in order to minimize lipase activity, total phenols, phytic acid and tannins content. Steamed grains were dried （12 ± 0.5% moisture content）, pearled, milled, sieved through sieve opening size of 0.234 mm and were used for study. Central composite rotatable design （CCRD） with three independent variables i.e. vanaspati, sugar and water for rehydration were used to design the experiments. Sensory responses and rehydration ratio were used to study the individual and interactive effects of variables. Sensory score for colour varied from taste 6.3-7.9, mouth feel 6.4-7.8, overall acceptability （OAA） 6.5-7.9 and rehydration ratio （RR） from 1.4 to 2.3. All the responses fitted into quadratic equation with R2 〉 0.80. Halwa dry mix was also evaluated for stability in polyethylene pouches at ambient conditions and the peroxide and free fatty acids value were 21.35 meqO2 kg^-1 fat, 0.55% （oleic acid）, respectively after 6 months of storage. Based on compromise optimization, optimum levels of the ingredients recommended with 86.4% desirability were： vanaspati 38.6 g 100 g^-1 pearl millet semolina （PMS）, sugar 88.7 g 100 g^-1 PMS and water for rehydration 151 mL 100 g^-1 dry mix.
文摘In this paper we present a performance evaluation of thermal spraying coated hot forging dies conducted in a production line. The High Velocity Oxy-Fuel process was used for the deposition of a tungsten carbide coating, which is characterized by its optimal adherence and low porosity. A metallurgical characterization of the layer was previously done, in order to obtain reference information to assist in the interpretation of the practical tests results. The coated die allowed an increase in productivity of 37.5%, besides better dimensional stability results through the process and legibility of printed numbers.
文摘Road surface condition evaluation involves the collection of data over pavement surface for different types of distresses. The exercise consumes a lot of resources if the whole road section length is surveyed and may be prone to errors as a result of surveyors＇ fatigue. It is therefore important to develop a representative sample to be used when evaluating road condition manually. This study aimed at determining an adequate sample size for section level as well as a way forward for network level condition evaluation of highways in Nepal. Again the study was conducted to quantify the effects of altering the sample unit size for performing a distress survey according to the PCI （pavement condition index） and SDI （surface distress index） method separately for asphalt surfaced roads. The effect of reducing/increasing sample unit size was investigated adopting visual examination through field survey by eight teams in July, 2015, along the section of Banepa-Bardibas highway. The PCI was then calculated for each sample unit using standard deduct curves and PCI calculation methodology as per SHRP （Strategic Highway Research Program） recommendations and the computation of SDI was done as per DoR （Department of Roads） guidelines. The results show that 13% sample unit are needed for SDI and 21% for PCI computation, however, the results are out of the significant level. This is higher than DoR and SHRP guidelines. Again no strong relationship is observed between SDI and PCI values.
基金supported by the "Applied Research and Multi-sectorial Program" (FIAM) (No. 5.2.1) granted by the Italian Cooperation and Development Agency (ICDA) to the Universidade Eduardo Mondlanethe Polytechnic University of Marche, Italy for the PhD scholarship provided to the first author as well as research funding for this work
文摘Finding alternative local sources of plant nutrients is a practical, low-cost, and long-term strategy. In this study, laboratory column experiments were conducted in a completely randomized design to evaluate the feasibility of using phosphate rock and dolostone as fertilizers or acid-neutralizing agents for application in tropical acid soils. The dissolution rates of different particle-size fractions(0.063–0.25, 0.25–0.5, and 0.5–2 mm) of both rocks were studied by citric acid solution at p H 4 and 2 and water, with extraction times of 1, 3, 5, 7, 12, 24, 72, 144, 240, and 360 h. The results showed that the dissolution of both rocks depended on the particle size,leaching solution, and extraction time. The dissolution rate of rock-forming minerals increased as the specific surface area increased,corresponding to a decrease in particle size. In all cases, the release kinetics was characterized by two phases: 1) a first stage of rapid release that lasted 24 h and would ensure short-term nutrient release, and 2) a second stage of slow release after 24 h, representing the long-term nutrient release efficiency. Both rocks were suitable as slow-release fertilizers in strongly acid soils and would ensure the replenishment of P, Ca, and Mg. A combination of fine and medium particle-size fractions should be used to ensure high nutrient-release efficiency. Much work could remain to determine the overall impact of considerable amounts of fresh rocks in soils.
