Contra-rotating small-sized axial fans are used as cooling fans for electric equipment. In the case of the contra-rotating rotors, the blade row distance between front and rear rotors is a key parameter for the perfor...Contra-rotating small-sized axial fans are used as cooling fans for electric equipment. In the case of the contra-rotating rotors, the blade row distance between front and rear rotors is a key parameter for the performance and stable operation. The wake and potential interference occur between the front and rear rotors and leakage flow from the front rotor tip influences on the flow condition of the rear rotor near the shroud when the blade row distance is small. Therefore, it is important to clarify the flow condition between front and rear rotors. The fan static pressure curves were obtained by the experimental apparatus and the numerical analysis was also conducted to investigate the internal flow between front and rear rotors. The leakage flow from the front rotor tip reaches the leading edge of the rear rotor when the blade row distance is small as L = 10 mm and the pressure fluctuations at the leading edge of the rear rotor tip becomes larger than those at other radial positions. In the present paper, the vorticity contour between front and rear rotors is shown and pressure fluctuations related to the leakage flow from the front rotor is investigated using the numerical analysis result. Then, suitable blade row distance for the contra-rotating small sized axial fan is discussed based on the internal flow condition.展开更多
Exhaust gas temperature is an important factor in NOx, THC and PM emissions of engines. Especially 2D temperature and concentration distribution plays an important role for the engine efficiency. A thermocouple is int...Exhaust gas temperature is an important factor in NOx, THC and PM emissions of engines. Especially 2D temperature and concentration distribution plays an important role for the engine efficiency. A thermocouple is intrinsically a point temperature measurement method and noncontact 2D temperature distribution cannot be attained by thermocouples. Recently, as a measurement technique with high sensitivity and high response, laser diagnostics has been developed and applied to the actual engine combustions. With these engineering developments, transient phenomena such as start-ups and load changes in engines have been gradually elucidated in various conditions. In this study, the theoretical and experimental research has been conducted in order to develop the noncontact and fast response 2D temperature and concentration distribution measurement method. The method is based on a Computed Tomography （CT） method using absorption spectra of water vapor at 1388 nm. It has been demonstrated that the method has been successfully applied to engine exhausts to measure 2D temperature distributions.展开更多
A remote open-path laser-induced breakdown spectroscopy(LIBS) system was designed and studied in the present work for the purpose of combining the LIBS technique with the steel production line. In this system, the rel...A remote open-path laser-induced breakdown spectroscopy(LIBS) system was designed and studied in the present work for the purpose of combining the LIBS technique with the steel production line. In this system, the relatively simple configuration and optics were employed to measure the steel samples at a remote distance and a hot sample temperature. The system has obtained a robustness for the deviation of the sample position because of the open-path and alloptical structure. The measurement was carried out at different sample temperatures by placing the samples in a muffle furnace with a window in the front door. The results show that the intensity of the spectral lines increased as the sample temperature increased. The influence of the sample temperature on the quantitative analysis of manganese in the steel samples was investigated by measuring ten standard steel samples at different temperatures. Three samples were selected as the test sample for the simulation measurement. The results show that, at the sample temperature of 500 ℃, the average relative error of prediction is 3.1% and the average relative standard deviation is 7.7%, respectively.展开更多
Contents of fly ash are important factors for the operation of coal-fired plants. Real-time monitoring of coal and fly ash such as unburned carbon in fly ash can be an indicator of the combustion conditions. Because o...Contents of fly ash are important factors for the operation of coal-fired plants. Real-time monitoring of coal and fly ash such as unburned carbon in fly ash can be an indicator of the combustion conditions. Because of the strong signal intensity and the relative simplicity of the LIBS (Laser- Induced Breakdown Spectroscopy) technique, LIBS can be applicable for real-time composition measurement of coal and fly ash. This research presented here focused on the clarification of the effects of plasma temperature and coexisting materials on quantitative measurement of fly ash contents. Quantitative capability of LIBS was improved using the proposed plasma temperature correction method. The CO2 effect was also discussed to accurately evaluate unburned carbon in fly ash in exhausts. Using the results shown in this study, quantitative measurement of fly ash contents has been improved for wider applications of LIBS to practical fields.展开更多
Laser-induced breakdown spectroscopy(LIBS)is a capable technique for elementary analysis,while LIBS quantitation is still under development.In quantitation,precise laser focusing plays an important role because it ens...Laser-induced breakdown spectroscopy(LIBS)is a capable technique for elementary analysis,while LIBS quantitation is still under development.In quantitation,precise laser focusing plays an important role because it ensures the distance between the laser and samples.In the present work,we employed spectral intensity as a direct way to assist laser focusing in LIBS quantitation for copper alloys.It is found that both the air emission and the copper line could be used to determine the position of the sample surface by referencing the intensity maximum.Nevertheless,the fine quantitation was only realized at the position where the air emission(e.g.O(I)777.4 nm)reached intensity maximum,and also in this way,a repeatable quantitation was successfully achieved even after 120 days.The results suggested that the LIBS quantitation was highly dependent on the focusing position of the laser,and spectra-assisted focusing could be a simple way to find the identical condition for different samples’detection.In the future,this method might be applicable in field measurements for LIBS analysis of solids.展开更多
Contra-rotating small-sized fans are used as cooling fans for electric equipment. The internal flow condition between the front and rear rotors of the contra-rotating small-sized fan is not known well especially at th...Contra-rotating small-sized fans are used as cooling fans for electric equipment. The internal flow condition between the front and rear rotors of the contra-rotating small-sized fan is not known well especially at the low flow rate. Furthermore, the blade row distance between the front and rear rotors is an important parameter for the contra-rotating small-sized fan and its influence on the internal flow condition is not clarified at the low flow rate. Therefore, the internal flow condition of the contra-rotating small-sized fan at the low flow rate is investigated by the numerical analysis in this research. The numerical analysis results are validated by comparing the fan static pressure curves of the numerical results to the experimental results. The internal flow condition at the low flow rate is clarified using the numerical models of the different blade row distance L = 10 mm and 30 mm. In the present paper, pressure fluctuations phase locked each front and rear rotor’s rotation are shown and the influences of the wake and the potential interference are discussed by the unsteady numerical analysis results at the low flow rate.展开更多
High pressure and large flow rate small-sized cooling fans are used for servers in data centers and there is a strong demand to increase its performance because of increase of quantity of heat from servers. Contra-rot...High pressure and large flow rate small-sized cooling fans are used for servers in data centers and there is a strong demand to increase its performance because of increase of quantity of heat from servers. Contra-rotating rotors have been adopted for some of high pressure and large flow rate cooling fans to meet the demand. The performance curve of the contra-rotating small-sized cooling fan with 40 mm square casing was investigated by an experimental apparatus and its internal flow condition was clarified by the numerical analysis. The fan static pressure of the front rotor was extremely low and it increased significantly at the rear rotor. The uniform flow was achieved at the inlet of the rear rotor because of the special shape of the casing between the front and rear rotors. On the other hand, the tip leakage flow was large enough to influence on the main flow of the test cooling fan by the design specification of high pressure with compact rotor diameter.展开更多
It is believed that mechanical stimuli, such as stretching of the extracellular matrix, are transmitted into cells via focal adhesion complexes and the actin cytoskeleton. Transmission dynamics of strain from the extr...It is believed that mechanical stimuli, such as stretching of the extracellular matrix, are transmitted into cells via focal adhesion complexes and the actin cytoskeleton. Transmission dynamics of strain from the extracellular matrix into intracellular organelles is crucial to clarify the mechanosensing mechanisms of cells. In this study, we observed deformation behavior of actin stress fibers under uniaxial stretch using an originally developed cell-stretching microelectromechanical system (MEMS) device. It was difficult to conduct in situ observation of cells under stretch using conventional cell stretching devices, because motion artifacts such as rigid displacement during stretch application were not negligible. Our novel cell-stretching MEMS device suppressed rigid displacement while stretching, and we succeeded in obtaining time-lapse images of stretched cells. Uniaxial strain with a 10% magnitude and strain rate of 0.5%/sec was applied to cells. Deformation behaviors of the cells and actin stress fibers were recorded using a confocal laser scanning microscope. In time-lapse images of stretched cells, strains along each stress fiber were measured manually. As a result, in cells with a relatively homogeneous stress fiber structure oriented in one direction, distribution of the axial strain on stress fibers generally corresponded to deformation of the stretching sheet on which the cells had adhered. However, in cells with a heterogeneous stress fiber structure oriented in several directions, we found that the strain distribution along stress fibers was not homogeneous. In regions around the cell nucleus, there was a more complicated strain distribution compared with other regions. Our results suggest the cell nucleus with a stiff mechanical resistance yields such a complicated strain distribution in stress fibers.展开更多
In recent years, tighter regulation has been already enforced on harmful substances such as NOx, CO, and particles. Considering the above situation, it is important to monitor controlling factors of engine systems in ...In recent years, tighter regulation has been already enforced on harmful substances such as NOx, CO, and particles. Considering the above situation, it is important to monitor controlling factors of engine systems in order to improve efficiencies of their operations. As to car engines, an increasing concern in environmental issues such as air pollution, global warming and petroleum depletion has helped drive researches into various ways. Laser diagnostics has been applied to measure species concentration in the actual industrial fields. However there are several challenges to proceed in applying laser diagnostics to practical application. Especially stability of the measurement system is one of the most difficult issues. The purpose of this research is the development of a prompt measurement technique which can be applicable to various engine conditions. The Tunable Diode Laser Absorption Spectroscopy （TDLAS） using the hollow fiber has been developed to satisfy above requirements. By using a hollow fiber, misalignment of an optical axis and vulnerability of measurement environment such as vibration can be greatly reduced with sensitive and fast response features. It was demonstrated that this method can be applicable to measure gas compositions in engine exhaust with a range of millisecond response time. A sensitive method using tunable UV diode laser absorption spectroscopy was also discussed to detect NOx in exhausts.展开更多
This study tried to apply biomass fuel to clean burner combustion under high load conditions by water addition. A newly developed injector mixes fuel rapidly with water inside of the injector with support of atomizing...This study tried to apply biomass fuel to clean burner combustion under high load conditions by water addition. A newly developed injector mixes fuel rapidly with water inside of the injector with support of atomizing air. The mixture composed of three-fluid is injected as spray into a flame stabilizer of burner. Investigation of emission performance of this injector shows that the internally rapid mixing type of injector is hopeful technique to introduce water into burner combustion. Combustion by this injector emits exceedingly less particulate matters at high load. NOx emission is strongly dependent on water flow rate.展开更多
It is thought that small hydropower generation is alternative energy, and the energy potential of small hydropower is large. The efficiency of small hydro turbines is lower than that of large one, and these small hydr...It is thought that small hydropower generation is alternative energy, and the energy potential of small hydropower is large. The efficiency of small hydro turbines is lower than that of large one, and these small hydro turbine’s common problems are out of operation by foreign materials. Then, there are demands for small hydro turbines to keep high per- formance and wide flow passage. Therefore, we adopted contra-rotating rotors which can be expected to achieve high performance and low-solidity rotors with wide flow passage in order to accomplish high performance and stable opera- tion. Final goal on this study is development of an electric appliance type small hydro turbine which has high portability and makes an effective use of the unused small hydro power energy source. In the present paper, the performance and the internal flow conditions in detail of contra-rotating small-sized axial flow hydro turbine are shown as a first step of the research with the numerical flow analysis. Then, a capability adopting contra-rotating rotors to an electric appliance type small hydro turbine was discussed. Furthermore, the high performance design for it was considered by the numeri- cal analysis results.展开更多
Patients with inflammatory bowel disease are known to have a high demand of recurrent evaluation for therapy and disease activity. Further, the risk of developing cancer during the disease progression is increasing fr...Patients with inflammatory bowel disease are known to have a high demand of recurrent evaluation for therapy and disease activity. Further, the risk of developing cancer during the disease progression is increasing from year to year. New, mostly non-radiant, quick to perform and quantitative methods are challenging, conventional endoscopy with biopsy as gold standard. Especially, new physical imaging approaches utilizing light and sound waves have facilitated the development of advanced functional and molecular modalities. Besides these advantages they hold the promise to predict personalized therapeutic responses and to spare frequent invasive procedures. Within this article we highlight their potential for initial diagnosis, assessment of disease activity and surveillance of cancer development in established techniques and recent advances such as wide-view full-spectrum endoscopy, chromoendoscopy, autofluorescence endoscopy, endocytoscopy, confocal laser endoscopy, multiphoton endoscopy, molecular imaging endoscopy, B-mode and Doppler ultrasound, contrast-enhanced ultrasound, ultrasound molecular imaging, and elastography.展开更多
A 385 nm InGaN/GaN LED on the sapphire with the nano-pattem was fabricated and its electroluminescence property was investigated in a three-dimensional （3D） space. The experimental results showed that the luminescen...A 385 nm InGaN/GaN LED on the sapphire with the nano-pattem was fabricated and its electroluminescence property was investigated in a three-dimensional （3D） space. The experimental results showed that the luminescent intensity of the LED was obviously oriented based on the nano-pattem of the sapphire substrate. And the optical interference was used to explain the luminescence orientation of the LED on the nano-pattemed substrate.展开更多
Inspection of a pipeline is essential for the safe use of such facilities. A trial sensor using an electromagnetic acoustic transducer (EMAT), which can generate the SH-mode plate wave propagating in the circumferenti...Inspection of a pipeline is essential for the safe use of such facilities. A trial sensor using an electromagnetic acoustic transducer (EMAT), which can generate the SH-mode plate wave propagating in the circumferential direction, has been developed to realize this objective. It consists of a circulating electromagnetic induction coil around the pipe and many permanent magnets arranged on the surface of the pipe in the circumferential direction. It is postulated that the intensity of the SH-mode plate wave propagating in the circumferential direction is dependent on any defects in the circumferential direction. A resonance method was then utilized to obtain a stronger received signal. As a result, it was confirmed that the resonance status can be detected. The relationship between the signal intensity and the pipe thickness was then evaluated. It was confirmed that the wall thickness of about 20% can be detected under a static condition. Finally, a moving test has been executed by using an axially traveling device manufactured by trial. The test pipes with different sizes of drilled holes were prepared. The change in the received signal intensity according to different sizes of the drilled holes was successfully detected.展开更多
This paper contains material presented by the first authors in CIMPA School at Kathmandu University.,July 26,27,28,2010,to be included in ,and is intended for a rambling introduction to number-theoretic concepts throu...This paper contains material presented by the first authors in CIMPA School at Kathmandu University.,July 26,27,28,2010,to be included in ,and is intended for a rambling introduction to number-theoretic concepts through built-in properties of(number-theoretic) special functions.We follow roughly the historical order of events from somewhat more modern point of view.§1 deals with Euler's fundamental ideas as expounded in [6] and ,from a more advanced standpoint.§2 gives some rudiments of Bernoulli numbers and polynomials as consequences of the partial fraction expansion.§3 states sieve-theoretic treatment of the Euler product.Thus,the events in §1-§3 more or less belong to Euler's era.§4 deals with RSA cryptography as motivated by Euler's function,with its several descriptions being given.§5 contains a slight generalization of Dirichlet's test on uniform convergence of series,which is more effectively used in §6 to elucidate Riemann's posthumous Fragment II than in [1].Thus §5-§6 belong to the Dirichlet-Riemann era.§7 gives the most general modular relation which is the culmination of the Riemann-Hecke-Bochner correspondence between modular forms and zeta-functions.Appendix gives a penetrating principle of the least period that appears in various contexts.展开更多
Mini centrifugal pumps having a diameter smaller than lOOmm are employed in many fields. But the design method for the mini centrifugal pump is not established because the internal flow condition for these small-sized...Mini centrifugal pumps having a diameter smaller than lOOmm are employed in many fields. But the design method for the mini centrifugal pump is not established because the internal flow condition for these small-sized fluid machines is not clarified and conventional theory is not suitable for small-sized pumps. Therefore, mini cen- trifugal pumps with simple structure were investigated by this research. Splitter blades were adopted in this re- search to improve the performance and the internal flow condition of mini centrifugal pump which had large blade outlet angle. The original impeller without the splitter blades and the impeller with the splitter blades were prepared for experiment. The performance tests are conducted with these rotors in order to investigate the effect of the splitter blades on performance and internal flow condition of mini centrifugal pump. On the other hand, a three dimensional unsteady numerical flow analysis was conducted to investigate the change of the internal flow according to the rotor rotation. It is clarified from the experimental results that the performance of the mini cen- trifugal pump is improved by the splitter blades. The blade-to-blade low velocity region was suppressed in the case with the splitter blades. In addition to that, the unsteady flows near the volute casing tongue were suppressed due to the splitter blades. In the present paper, the performance of the mini centrifugal pump is shown and the un- steady flow condition is clarified with the results of the numerical flow analysis. Furthermore, the effects of the splitter blades on the performance and the unsteady internal flow condition are investigated.展开更多
Design method for a mini centrifugal pump is not established because the internal flow condition for these small-sized fluid machines is not clarified and conventional theory is not suitable for small-sized pumps. The...Design method for a mini centrifugal pump is not established because the internal flow condition for these small-sized fluid machines is not clarified and conventional theory is not suitable for small-sized pumps. Then, a semi-open impeller for the mini centrifugal pump with 55mm impeller diameter is adopted in this research to take simplicity and maintenance into consideration. Splitter blades are adopted in this research to improve the performance and internal flow condition of mini centrifugal pump having large blade outlet angle. The performance tests are conducted with these rotors in order to investigate the effect of the splitter blades on the performance and internal flow condition of the mini centrifugal pump. A three dimensional steady numerical flow analysis is conducted to analyze rotor, volute efficiency and loss caused by a vortex. It is clarified from the experimental results that the performance of the mini centrifugal pump is improved by the effect of the splitter blades. Flow condition at outlet of the rotor becomes uniform and back flow regions are suppressed in the case with the splitter blades.Further, the volute efficiency increases and the vortex loss decreases. In the present paper, the performance of the mini centrifugal pump is shown and the flow condition is clarified with the results of the experiment and the numerical flow analysis. Furthermore, the performance analyses of the mini centrifugal pumps with and without the splitter blades are conducted.展开更多
Small-sized axial fans are used as air coolers for electric equipments.But there is a strong demand for higher power of fans according to the increase of quantity of heat from electric devices.Therefore,higher rotatio...Small-sized axial fans are used as air coolers for electric equipments.But there is a strong demand for higher power of fans according to the increase of quantity of heat from electric devices.Therefore,higher rotational speed design is conducted,although it causes the deterioration of the efficiency and the increase of noise.Then the adoption of contra-rotating rotors for the small-sized axial fan is proposed for the improvement of the performance.In the present paper,the performance and the internal flow condition of the small-sized axial fan are shown as a first step of the research for the contra-rotating small-sized axial fan and the important points to apply contra-rotating rotors to the small-sized axial fan are discussed.Furthermore,the numerical flow analysis is conducted to investigate the performance of the contra-rotating small-sized axial fan and internal flow conditions and pressure distributions are clarified and the effect of contra-rotating rotors is considered.展开更多
文摘Contra-rotating small-sized axial fans are used as cooling fans for electric equipment. In the case of the contra-rotating rotors, the blade row distance between front and rear rotors is a key parameter for the performance and stable operation. The wake and potential interference occur between the front and rear rotors and leakage flow from the front rotor tip influences on the flow condition of the rear rotor near the shroud when the blade row distance is small. Therefore, it is important to clarify the flow condition between front and rear rotors. The fan static pressure curves were obtained by the experimental apparatus and the numerical analysis was also conducted to investigate the internal flow between front and rear rotors. The leakage flow from the front rotor tip reaches the leading edge of the rear rotor when the blade row distance is small as L = 10 mm and the pressure fluctuations at the leading edge of the rear rotor tip becomes larger than those at other radial positions. In the present paper, the vorticity contour between front and rear rotors is shown and pressure fluctuations related to the leakage flow from the front rotor is investigated using the numerical analysis result. Then, suitable blade row distance for the contra-rotating small sized axial fan is discussed based on the internal flow condition.
文摘Exhaust gas temperature is an important factor in NOx, THC and PM emissions of engines. Especially 2D temperature and concentration distribution plays an important role for the engine efficiency. A thermocouple is intrinsically a point temperature measurement method and noncontact 2D temperature distribution cannot be attained by thermocouples. Recently, as a measurement technique with high sensitivity and high response, laser diagnostics has been developed and applied to the actual engine combustions. With these engineering developments, transient phenomena such as start-ups and load changes in engines have been gradually elucidated in various conditions. In this study, the theoretical and experimental research has been conducted in order to develop the noncontact and fast response 2D temperature and concentration distribution measurement method. The method is based on a Computed Tomography （CT） method using absorption spectra of water vapor at 1388 nm. It has been demonstrated that the method has been successfully applied to engine exhausts to measure 2D temperature distributions.
基金supported by National Natural Science Foundation of China (Nos. 51506171 and 51675415)National Natural Science Foundation of China for Key Program (No. 51335009)+1 种基金National Key Research and Development Program of China (No. 2017YFD0700200)the joint research fund between Tokushima University and Xi’an Jiaotong University
文摘A remote open-path laser-induced breakdown spectroscopy(LIBS) system was designed and studied in the present work for the purpose of combining the LIBS technique with the steel production line. In this system, the relatively simple configuration and optics were employed to measure the steel samples at a remote distance and a hot sample temperature. The system has obtained a robustness for the deviation of the sample position because of the open-path and alloptical structure. The measurement was carried out at different sample temperatures by placing the samples in a muffle furnace with a window in the front door. The results show that the intensity of the spectral lines increased as the sample temperature increased. The influence of the sample temperature on the quantitative analysis of manganese in the steel samples was investigated by measuring ten standard steel samples at different temperatures. Three samples were selected as the test sample for the simulation measurement. The results show that, at the sample temperature of 500 ℃, the average relative error of prediction is 3.1% and the average relative standard deviation is 7.7%, respectively.
文摘Contents of fly ash are important factors for the operation of coal-fired plants. Real-time monitoring of coal and fly ash such as unburned carbon in fly ash can be an indicator of the combustion conditions. Because of the strong signal intensity and the relative simplicity of the LIBS (Laser- Induced Breakdown Spectroscopy) technique, LIBS can be applicable for real-time composition measurement of coal and fly ash. This research presented here focused on the clarification of the effects of plasma temperature and coexisting materials on quantitative measurement of fly ash contents. Quantitative capability of LIBS was improved using the proposed plasma temperature correction method. The CO2 effect was also discussed to accurately evaluate unburned carbon in fly ash in exhausts. Using the results shown in this study, quantitative measurement of fly ash contents has been improved for wider applications of LIBS to practical fields.
基金financially supported by the Provincial Key Research and Development Program of Shandong,China(No.2019GHZ010)the Natural Science Foundation of Shandong Province(No.ZR2020MF123)+1 种基金National Natural Science Foundation of China(Nos.61975190 and12174359)the Fundamental Research Funds for the Central Universities(No.202161002)。
文摘Laser-induced breakdown spectroscopy(LIBS)is a capable technique for elementary analysis,while LIBS quantitation is still under development.In quantitation,precise laser focusing plays an important role because it ensures the distance between the laser and samples.In the present work,we employed spectral intensity as a direct way to assist laser focusing in LIBS quantitation for copper alloys.It is found that both the air emission and the copper line could be used to determine the position of the sample surface by referencing the intensity maximum.Nevertheless,the fine quantitation was only realized at the position where the air emission(e.g.O(I)777.4 nm)reached intensity maximum,and also in this way,a repeatable quantitation was successfully achieved even after 120 days.The results suggested that the LIBS quantitation was highly dependent on the focusing position of the laser,and spectra-assisted focusing could be a simple way to find the identical condition for different samples’detection.In the future,this method might be applicable in field measurements for LIBS analysis of solids.
文摘Contra-rotating small-sized fans are used as cooling fans for electric equipment. The internal flow condition between the front and rear rotors of the contra-rotating small-sized fan is not known well especially at the low flow rate. Furthermore, the blade row distance between the front and rear rotors is an important parameter for the contra-rotating small-sized fan and its influence on the internal flow condition is not clarified at the low flow rate. Therefore, the internal flow condition of the contra-rotating small-sized fan at the low flow rate is investigated by the numerical analysis in this research. The numerical analysis results are validated by comparing the fan static pressure curves of the numerical results to the experimental results. The internal flow condition at the low flow rate is clarified using the numerical models of the different blade row distance L = 10 mm and 30 mm. In the present paper, pressure fluctuations phase locked each front and rear rotor’s rotation are shown and the influences of the wake and the potential interference are discussed by the unsteady numerical analysis results at the low flow rate.
文摘High pressure and large flow rate small-sized cooling fans are used for servers in data centers and there is a strong demand to increase its performance because of increase of quantity of heat from servers. Contra-rotating rotors have been adopted for some of high pressure and large flow rate cooling fans to meet the demand. The performance curve of the contra-rotating small-sized cooling fan with 40 mm square casing was investigated by an experimental apparatus and its internal flow condition was clarified by the numerical analysis. The fan static pressure of the front rotor was extremely low and it increased significantly at the rear rotor. The uniform flow was achieved at the inlet of the rear rotor because of the special shape of the casing between the front and rear rotors. On the other hand, the tip leakage flow was large enough to influence on the main flow of the test cooling fan by the design specification of high pressure with compact rotor diameter.
文摘It is believed that mechanical stimuli, such as stretching of the extracellular matrix, are transmitted into cells via focal adhesion complexes and the actin cytoskeleton. Transmission dynamics of strain from the extracellular matrix into intracellular organelles is crucial to clarify the mechanosensing mechanisms of cells. In this study, we observed deformation behavior of actin stress fibers under uniaxial stretch using an originally developed cell-stretching microelectromechanical system (MEMS) device. It was difficult to conduct in situ observation of cells under stretch using conventional cell stretching devices, because motion artifacts such as rigid displacement during stretch application were not negligible. Our novel cell-stretching MEMS device suppressed rigid displacement while stretching, and we succeeded in obtaining time-lapse images of stretched cells. Uniaxial strain with a 10% magnitude and strain rate of 0.5%/sec was applied to cells. Deformation behaviors of the cells and actin stress fibers were recorded using a confocal laser scanning microscope. In time-lapse images of stretched cells, strains along each stress fiber were measured manually. As a result, in cells with a relatively homogeneous stress fiber structure oriented in one direction, distribution of the axial strain on stress fibers generally corresponded to deformation of the stretching sheet on which the cells had adhered. However, in cells with a heterogeneous stress fiber structure oriented in several directions, we found that the strain distribution along stress fibers was not homogeneous. In regions around the cell nucleus, there was a more complicated strain distribution compared with other regions. Our results suggest the cell nucleus with a stiff mechanical resistance yields such a complicated strain distribution in stress fibers.
文摘In recent years, tighter regulation has been already enforced on harmful substances such as NOx, CO, and particles. Considering the above situation, it is important to monitor controlling factors of engine systems in order to improve efficiencies of their operations. As to car engines, an increasing concern in environmental issues such as air pollution, global warming and petroleum depletion has helped drive researches into various ways. Laser diagnostics has been applied to measure species concentration in the actual industrial fields. However there are several challenges to proceed in applying laser diagnostics to practical application. Especially stability of the measurement system is one of the most difficult issues. The purpose of this research is the development of a prompt measurement technique which can be applicable to various engine conditions. The Tunable Diode Laser Absorption Spectroscopy （TDLAS） using the hollow fiber has been developed to satisfy above requirements. By using a hollow fiber, misalignment of an optical axis and vulnerability of measurement environment such as vibration can be greatly reduced with sensitive and fast response features. It was demonstrated that this method can be applicable to measure gas compositions in engine exhaust with a range of millisecond response time. A sensitive method using tunable UV diode laser absorption spectroscopy was also discussed to detect NOx in exhausts.
文摘This study tried to apply biomass fuel to clean burner combustion under high load conditions by water addition. A newly developed injector mixes fuel rapidly with water inside of the injector with support of atomizing air. The mixture composed of three-fluid is injected as spray into a flame stabilizer of burner. Investigation of emission performance of this injector shows that the internally rapid mixing type of injector is hopeful technique to introduce water into burner combustion. Combustion by this injector emits exceedingly less particulate matters at high load. NOx emission is strongly dependent on water flow rate.
文摘It is thought that small hydropower generation is alternative energy, and the energy potential of small hydropower is large. The efficiency of small hydro turbines is lower than that of large one, and these small hydro turbine’s common problems are out of operation by foreign materials. Then, there are demands for small hydro turbines to keep high per- formance and wide flow passage. Therefore, we adopted contra-rotating rotors which can be expected to achieve high performance and low-solidity rotors with wide flow passage in order to accomplish high performance and stable opera- tion. Final goal on this study is development of an electric appliance type small hydro turbine which has high portability and makes an effective use of the unused small hydro power energy source. In the present paper, the performance and the internal flow conditions in detail of contra-rotating small-sized axial flow hydro turbine are shown as a first step of the research with the numerical flow analysis. Then, a capability adopting contra-rotating rotors to an electric appliance type small hydro turbine was discussed. Furthermore, the high performance design for it was considered by the numeri- cal analysis results.
基金Supported by Interdisciplinary Center for Clinical Research of the University Medical Center of Erlangen(to Knieling F)Erlangen Graduate School in Advanced Optical Technologies by the German Research Foundation in the framework of the German excellence initiative(to Waldner MJ)
文摘Patients with inflammatory bowel disease are known to have a high demand of recurrent evaluation for therapy and disease activity. Further, the risk of developing cancer during the disease progression is increasing from year to year. New, mostly non-radiant, quick to perform and quantitative methods are challenging, conventional endoscopy with biopsy as gold standard. Especially, new physical imaging approaches utilizing light and sound waves have facilitated the development of advanced functional and molecular modalities. Besides these advantages they hold the promise to predict personalized therapeutic responses and to spare frequent invasive procedures. Within this article we highlight their potential for initial diagnosis, assessment of disease activity and surveillance of cancer development in established techniques and recent advances such as wide-view full-spectrum endoscopy, chromoendoscopy, autofluorescence endoscopy, endocytoscopy, confocal laser endoscopy, multiphoton endoscopy, molecular imaging endoscopy, B-mode and Doppler ultrasound, contrast-enhanced ultrasound, ultrasound molecular imaging, and elastography.
文摘A 385 nm InGaN/GaN LED on the sapphire with the nano-pattem was fabricated and its electroluminescence property was investigated in a three-dimensional （3D） space. The experimental results showed that the luminescent intensity of the LED was obviously oriented based on the nano-pattem of the sapphire substrate. And the optical interference was used to explain the luminescence orientation of the LED on the nano-pattemed substrate.
文摘Inspection of a pipeline is essential for the safe use of such facilities. A trial sensor using an electromagnetic acoustic transducer (EMAT), which can generate the SH-mode plate wave propagating in the circumferential direction, has been developed to realize this objective. It consists of a circulating electromagnetic induction coil around the pipe and many permanent magnets arranged on the surface of the pipe in the circumferential direction. It is postulated that the intensity of the SH-mode plate wave propagating in the circumferential direction is dependent on any defects in the circumferential direction. A resonance method was then utilized to obtain a stronger received signal. As a result, it was confirmed that the resonance status can be detected. The relationship between the signal intensity and the pipe thickness was then evaluated. It was confirmed that the wall thickness of about 20% can be detected under a static condition. Finally, a moving test has been executed by using an axially traveling device manufactured by trial. The test pipes with different sizes of drilled holes were prepared. The change in the received signal intensity according to different sizes of the drilled holes was successfully detected.
文摘This paper contains material presented by the first authors in CIMPA School at Kathmandu University.,July 26,27,28,2010,to be included in ,and is intended for a rambling introduction to number-theoretic concepts through built-in properties of(number-theoretic) special functions.We follow roughly the historical order of events from somewhat more modern point of view.§1 deals with Euler's fundamental ideas as expounded in [6] and ,from a more advanced standpoint.§2 gives some rudiments of Bernoulli numbers and polynomials as consequences of the partial fraction expansion.§3 states sieve-theoretic treatment of the Euler product.Thus,the events in §1-§3 more or less belong to Euler's era.§4 deals with RSA cryptography as motivated by Euler's function,with its several descriptions being given.§5 contains a slight generalization of Dirichlet's test on uniform convergence of series,which is more effectively used in §6 to elucidate Riemann's posthumous Fragment II than in [1].Thus §5-§6 belong to the Dirichlet-Riemann era.§7 gives the most general modular relation which is the culmination of the Riemann-Hecke-Bochner correspondence between modular forms and zeta-functions.Appendix gives a penetrating principle of the least period that appears in various contexts.
文摘Mini centrifugal pumps having a diameter smaller than lOOmm are employed in many fields. But the design method for the mini centrifugal pump is not established because the internal flow condition for these small-sized fluid machines is not clarified and conventional theory is not suitable for small-sized pumps. Therefore, mini cen- trifugal pumps with simple structure were investigated by this research. Splitter blades were adopted in this re- search to improve the performance and the internal flow condition of mini centrifugal pump which had large blade outlet angle. The original impeller without the splitter blades and the impeller with the splitter blades were prepared for experiment. The performance tests are conducted with these rotors in order to investigate the effect of the splitter blades on performance and internal flow condition of mini centrifugal pump. On the other hand, a three dimensional unsteady numerical flow analysis was conducted to investigate the change of the internal flow according to the rotor rotation. It is clarified from the experimental results that the performance of the mini cen- trifugal pump is improved by the splitter blades. The blade-to-blade low velocity region was suppressed in the case with the splitter blades. In addition to that, the unsteady flows near the volute casing tongue were suppressed due to the splitter blades. In the present paper, the performance of the mini centrifugal pump is shown and the un- steady flow condition is clarified with the results of the numerical flow analysis. Furthermore, the effects of the splitter blades on the performance and the unsteady internal flow condition are investigated.
文摘Design method for a mini centrifugal pump is not established because the internal flow condition for these small-sized fluid machines is not clarified and conventional theory is not suitable for small-sized pumps. Then, a semi-open impeller for the mini centrifugal pump with 55mm impeller diameter is adopted in this research to take simplicity and maintenance into consideration. Splitter blades are adopted in this research to improve the performance and internal flow condition of mini centrifugal pump having large blade outlet angle. The performance tests are conducted with these rotors in order to investigate the effect of the splitter blades on the performance and internal flow condition of the mini centrifugal pump. A three dimensional steady numerical flow analysis is conducted to analyze rotor, volute efficiency and loss caused by a vortex. It is clarified from the experimental results that the performance of the mini centrifugal pump is improved by the effect of the splitter blades. Flow condition at outlet of the rotor becomes uniform and back flow regions are suppressed in the case with the splitter blades.Further, the volute efficiency increases and the vortex loss decreases. In the present paper, the performance of the mini centrifugal pump is shown and the flow condition is clarified with the results of the experiment and the numerical flow analysis. Furthermore, the performance analyses of the mini centrifugal pumps with and without the splitter blades are conducted.
基金supports by the project research aid from The University of Tokushima,Japan Science and Technology Agency and Komiya research aid
文摘Small-sized axial fans are used as air coolers for electric equipments.But there is a strong demand for higher power of fans according to the increase of quantity of heat from electric devices.Therefore,higher rotational speed design is conducted,although it causes the deterioration of the efficiency and the increase of noise.Then the adoption of contra-rotating rotors for the small-sized axial fan is proposed for the improvement of the performance.In the present paper,the performance and the internal flow condition of the small-sized axial fan are shown as a first step of the research for the contra-rotating small-sized axial fan and the important points to apply contra-rotating rotors to the small-sized axial fan are discussed.Furthermore,the numerical flow analysis is conducted to investigate the performance of the contra-rotating small-sized axial fan and internal flow conditions and pressure distributions are clarified and the effect of contra-rotating rotors is considered.
