针对复杂管道系统内水流冲击滞留气团现象,采用VOF模型(Volume of Fluid Model)进行了数值模拟计算,并与一维模型进行了比较计算分析,结果表明:系统的最大压力并不总是气团的最大压力,有可能还会叠加水体对管壁的撞击而形成的突然升高...针对复杂管道系统内水流冲击滞留气团现象,采用VOF模型(Volume of Fluid Model)进行了数值模拟计算,并与一维模型进行了比较计算分析,结果表明:系统的最大压力并不总是气团的最大压力,有可能还会叠加水体对管壁的撞击而形成的突然升高压力。与实验实测结果的比较分析表明:采用VOF模型,能够较精细地仿真水流冲击滞留气团现象的气团形态、流场结构以及压力分布等的变化过程,其压力数值计算结果与实验实测基本吻合,其计算误差明显小于现有一维模型的计算误差,是深入研究该复杂瞬变流现象的有效方法。展开更多
A computational mass transfer model is proposed for predicting the concentration profile and Murphree efficiency of sieve tray distillation column. The proposed model is based on using modified c＇2 -εc＇ two equatio...A computational mass transfer model is proposed for predicting the concentration profile and Murphree efficiency of sieve tray distillation column. The proposed model is based on using modified c＇2 -εc＇ two equations formulation for closing the differential turbulent mass transfer equation with improvement by considering the vapor injected from the sieve hole to be three dimensional. The predicted concentration distributions by using proposed model were checked by experimental work conducted on a sieve tray simulator of 1.2 meters in diameter for desorbing the dissolved oxygen in the feed water by blowing air. The model predictions were confirmed by the experimental measurement. The validation of the proposed model was further tested by comparing the simulated result with the performance of an industrial scale sieve tray distillation column reported by Kunesh et al. for the stripping of toluene from its water solution. The predicted outlet concentration of each tray and the Murphree tray efficiencies under different operating conditions were in agreement with the published data. The simulated turbulent mass transfer diffusivity on each tray was within the range of the experimental result in the same sieve column reported by Cai et al. In addition, the prediction of the influence of sieve tray structure on the tray efficiency by using the proposed model was demonstrated.展开更多
Based on real-time digital simulations(RTDS),a laboratory environment similar to the real-time operation situation of the Three Gorges Hydropower Station is established.Then,the causes for the power fluctuation of the...Based on real-time digital simulations(RTDS),a laboratory environment similar to the real-time operation situation of the Three Gorges Hydropower Station is established.Then,the causes for the power fluctuation of the second generator by errors in the rotor rotating speed calculation are found,and the tuning method of the speed related parameters are given.The damping and reverse tuning characteristics of power system stabilizers(PSSs)in the digital automatic voltage regulator(AVR)are compared and investigated in the frequency range of 0.18-1.1 Hz.The efficiency of the proposed tuning method for ensuring power system stability is verified by RTDS.Finally,field tests show the validity of the laboratory test results.展开更多
Objective： HPP （Hypophosphatasia） is a congenital disease characterized by a deficiency of tissue-specific ALP （alkaline phosphatase）, which causes the generation of abnormal bone and tooth tissue. The clinical m...Objective： HPP （Hypophosphatasia） is a congenital disease characterized by a deficiency of tissue-specific ALP （alkaline phosphatase）, which causes the generation of abnormal bone and tooth tissue. The clinical manifestations are variable, from neonatal forms with high mortality to milder adult forms with fractures and osteomalacia. The present study reports a clinical case of HPP, with emphasis on the physical characteristics and laboratory tests. The patient was attended at the medical genetics outpatient clinic of the Association of Parents and Friends of the Exceptional of Manaus （Associa？？o de Pais e Amigos dos Excepcionais-APAE/Manaus）. Methodology： For the case report, anamnesis, peripheral blood G-band karyotyping, Vitamin and ALP dosage and resonance examination were performed. Results： A.M.M.S, 9 years, non-consanguineous parents, no bone disease in the family, with one sister from the mother. Birth weight AGA without intercurrence. The patient presented a slight delay in psycho-motor development and was diagnosed with craniostenosis through CNS imaging examination. The physical examination, in addition to a short stature, showed dolichocephaly, frontal bossing, curved tibias and great dental compromise with many early cavities and loss of teeth. Laboratory evaluation： ALP dosage： 63/L （N = 69-325）; Vitamin B6 dosage： 27.4 （5.2-34.1）. The mother and the younger sister also had an ALP result below that expected for the age. Conclusions： The clinical phenotype and laboratory diagnosis of the patient were compatible with ICD Q78 HPP.展开更多
In this paper, we present the resuks of the BitTorrent measurement study. Two sources of BitTorrent data were utilised： meta- data files and the logs of one of the currently most popular BitTorrent clients--gTorrent....In this paper, we present the resuks of the BitTorrent measurement study. Two sources of BitTorrent data were utilised： meta- data files and the logs of one of the currently most popular BitTorrent clients--gTorrent. Experimental data were collected for fifteen days from the popular torrent-discovery site thepiratebay.org （more than 30 000 torrents were captured and analysed）. During this pe- riod the activity and logs of an unmodified version of μTorrent client downloading ses- sions were also captured. The obtained ex- perimental results are swarm-oriented, which allows us to look at BitTorrent and its users from an exchanged resources perspective. Moreover, comparative analysis of the clients＇ connections with and without the μTP proto- col is carried out to verify the extent to which μTP improves BitTorrent transmissions. To the authors＇ best knowledge, none of the previous studies have addressed these issues.展开更多
The performance of masonry walls reinforced using innovative polymer grids embedded into thin plaster layers as a tool for the seismic enhancement of brick masonry buildings has been investigated by experimental tests...The performance of masonry walls reinforced using innovative polymer grids embedded into thin plaster layers as a tool for the seismic enhancement of brick masonry buildings has been investigated by experimental tests. A number of diagonal compression, shear compression and out-of-plane tests were executed on sample panels; experimental activities included pseudo-dynamic and shaking table tests on infills and reduced scaled building mock-ups, respectively. The results of the experimental activities are presented and discussed. Experimental campaigns have been supported by theoretical and numerical investigations; based on the experimental data and on the results of detailed numerical simulations, simplified models for the design of the retrofitting intervention are hereinafter proposed. The models：, calibrated on the experimental evidence, properly consider the collapse mechanisms as well as the grid effect in the evolution of the above mentioned mechanisms.展开更多
This article intends to report a rare case of massive pericardial effusion as the first manifestation of hypothyroidism. A 45-year-old male patient, accompanied by a cardiology department, suddenly started to present ...This article intends to report a rare case of massive pericardial effusion as the first manifestation of hypothyroidism. A 45-year-old male patient, accompanied by a cardiology department, suddenly started to present signs of dyspnea and tiredness. He was submitted to an echocardiogram and diagnosed with dilated cardiomyopathy associated with a moderate pericardial effusion and low ejection of fraction. The laboratory tests showed elevated TSH levels （13.20 mIU/L）, what leads to the hypothyroidism diagnose and enable to start the treatment with levothyroxine. The patient has not followed correctly the treatment, reason why he has not showed any improves. He was admitted in the hospital to cardiology monitoring and the chest radiography confirmed an intense pericardial effusion. Then, the patient was submitted to the pericardiocentesis procedure, which was capable of remove the pericardial fluid for laboratory analysis and fragment of the pericardial sac for neoplastic cell research. After the hospital discharge, he was maintained in outpatient follow-up, when showed an important improvement in the clinical state.展开更多
Taking Zhuoyu reservoir in Shannan of Tibet as the test site,the authors collected soil samples for laboratory analysis,and devised infiltration-clogging equipment for laboratory test to research the effect of cloggin...Taking Zhuoyu reservoir in Shannan of Tibet as the test site,the authors collected soil samples for laboratory analysis,and devised infiltration-clogging equipment for laboratory test to research the effect of clogging process on permeability of loose dam foundation of plateau reservoir.Through laboratory test,the soil can cause clogging effect by itself,and the effect of clogging is relative to the water pressure.The clogging effect can be caused obviously by adding fine particles,and the clogging effect of the particles with 0.063-0.25 mm diameter is best,which verifies the rationality of the optimal diameter interval.It provides the realistic significance for the anti-seepage of the plateau reservoir dam foundation.展开更多
文摘针对复杂管道系统内水流冲击滞留气团现象,采用VOF模型(Volume of Fluid Model)进行了数值模拟计算,并与一维模型进行了比较计算分析,结果表明:系统的最大压力并不总是气团的最大压力,有可能还会叠加水体对管壁的撞击而形成的突然升高压力。与实验实测结果的比较分析表明:采用VOF模型,能够较精细地仿真水流冲击滞留气团现象的气团形态、流场结构以及压力分布等的变化过程,其压力数值计算结果与实验实测基本吻合,其计算误差明显小于现有一维模型的计算误差,是深入研究该复杂瞬变流现象的有效方法。
基金Supported by the National lqatural Science Foundation of China （20736005）.
文摘A computational mass transfer model is proposed for predicting the concentration profile and Murphree efficiency of sieve tray distillation column. The proposed model is based on using modified c＇2 -εc＇ two equations formulation for closing the differential turbulent mass transfer equation with improvement by considering the vapor injected from the sieve hole to be three dimensional. The predicted concentration distributions by using proposed model were checked by experimental work conducted on a sieve tray simulator of 1.2 meters in diameter for desorbing the dissolved oxygen in the feed water by blowing air. The model predictions were confirmed by the experimental measurement. The validation of the proposed model was further tested by comparing the simulated result with the performance of an industrial scale sieve tray distillation column reported by Kunesh et al. for the stripping of toluene from its water solution. The predicted outlet concentration of each tray and the Murphree tray efficiencies under different operating conditions were in agreement with the published data. The simulated turbulent mass transfer diffusivity on each tray was within the range of the experimental result in the same sieve column reported by Cai et al. In addition, the prediction of the influence of sieve tray structure on the tray efficiency by using the proposed model was demonstrated.
文摘Based on real-time digital simulations(RTDS),a laboratory environment similar to the real-time operation situation of the Three Gorges Hydropower Station is established.Then,the causes for the power fluctuation of the second generator by errors in the rotor rotating speed calculation are found,and the tuning method of the speed related parameters are given.The damping and reverse tuning characteristics of power system stabilizers(PSSs)in the digital automatic voltage regulator(AVR)are compared and investigated in the frequency range of 0.18-1.1 Hz.The efficiency of the proposed tuning method for ensuring power system stability is verified by RTDS.Finally,field tests show the validity of the laboratory test results.
文摘Objective： HPP （Hypophosphatasia） is a congenital disease characterized by a deficiency of tissue-specific ALP （alkaline phosphatase）, which causes the generation of abnormal bone and tooth tissue. The clinical manifestations are variable, from neonatal forms with high mortality to milder adult forms with fractures and osteomalacia. The present study reports a clinical case of HPP, with emphasis on the physical characteristics and laboratory tests. The patient was attended at the medical genetics outpatient clinic of the Association of Parents and Friends of the Exceptional of Manaus （Associa？？o de Pais e Amigos dos Excepcionais-APAE/Manaus）. Methodology： For the case report, anamnesis, peripheral blood G-band karyotyping, Vitamin and ALP dosage and resonance examination were performed. Results： A.M.M.S, 9 years, non-consanguineous parents, no bone disease in the family, with one sister from the mother. Birth weight AGA without intercurrence. The patient presented a slight delay in psycho-motor development and was diagnosed with craniostenosis through CNS imaging examination. The physical examination, in addition to a short stature, showed dolichocephaly, frontal bossing, curved tibias and great dental compromise with many early cavities and loss of teeth. Laboratory evaluation： ALP dosage： 63/L （N = 69-325）; Vitamin B6 dosage： 27.4 （5.2-34.1）. The mother and the younger sister also had an ALP result below that expected for the age. Conclusions： The clinical phenotype and laboratory diagnosis of the patient were compatible with ICD Q78 HPP.
基金partially supported by the Polish National Science Center under Grant No.2011/01/D/ST7/05054
文摘In this paper, we present the resuks of the BitTorrent measurement study. Two sources of BitTorrent data were utilised： meta- data files and the logs of one of the currently most popular BitTorrent clients--gTorrent. Experimental data were collected for fifteen days from the popular torrent-discovery site thepiratebay.org （more than 30 000 torrents were captured and analysed）. During this pe- riod the activity and logs of an unmodified version of μTorrent client downloading ses- sions were also captured. The obtained ex- perimental results are swarm-oriented, which allows us to look at BitTorrent and its users from an exchanged resources perspective. Moreover, comparative analysis of the clients＇ connections with and without the μTP proto- col is carried out to verify the extent to which μTP improves BitTorrent transmissions. To the authors＇ best knowledge, none of the previous studies have addressed these issues.
文摘The performance of masonry walls reinforced using innovative polymer grids embedded into thin plaster layers as a tool for the seismic enhancement of brick masonry buildings has been investigated by experimental tests. A number of diagonal compression, shear compression and out-of-plane tests were executed on sample panels; experimental activities included pseudo-dynamic and shaking table tests on infills and reduced scaled building mock-ups, respectively. The results of the experimental activities are presented and discussed. Experimental campaigns have been supported by theoretical and numerical investigations; based on the experimental data and on the results of detailed numerical simulations, simplified models for the design of the retrofitting intervention are hereinafter proposed. The models：, calibrated on the experimental evidence, properly consider the collapse mechanisms as well as the grid effect in the evolution of the above mentioned mechanisms.
文摘This article intends to report a rare case of massive pericardial effusion as the first manifestation of hypothyroidism. A 45-year-old male patient, accompanied by a cardiology department, suddenly started to present signs of dyspnea and tiredness. He was submitted to an echocardiogram and diagnosed with dilated cardiomyopathy associated with a moderate pericardial effusion and low ejection of fraction. The laboratory tests showed elevated TSH levels （13.20 mIU/L）, what leads to the hypothyroidism diagnose and enable to start the treatment with levothyroxine. The patient has not followed correctly the treatment, reason why he has not showed any improves. He was admitted in the hospital to cardiology monitoring and the chest radiography confirmed an intense pericardial effusion. Then, the patient was submitted to the pericardiocentesis procedure, which was capable of remove the pericardial fluid for laboratory analysis and fragment of the pericardial sac for neoplastic cell research. After the hospital discharge, he was maintained in outpatient follow-up, when showed an important improvement in the clinical state.
基金Supported by Project of the National Natural Science Foundation of China(No.41072197)
文摘Taking Zhuoyu reservoir in Shannan of Tibet as the test site,the authors collected soil samples for laboratory analysis,and devised infiltration-clogging equipment for laboratory test to research the effect of clogging process on permeability of loose dam foundation of plateau reservoir.Through laboratory test,the soil can cause clogging effect by itself,and the effect of clogging is relative to the water pressure.The clogging effect can be caused obviously by adding fine particles,and the clogging effect of the particles with 0.063-0.25 mm diameter is best,which verifies the rationality of the optimal diameter interval.It provides the realistic significance for the anti-seepage of the plateau reservoir dam foundation.
