目的:分析养老机构服务质量的现状及影响因素。方法:采取便利取样法对深圳市养老机构217位老年人进行问卷调查,采用SERVQL量表评估老年人的感知服务质量、期望服务质量及服务质量满意度。结果:感知服务水平与期望服务水平的差值为?7.91...目的:分析养老机构服务质量的现状及影响因素。方法:采取便利取样法对深圳市养老机构217位老年人进行问卷调查,采用SERVQL量表评估老年人的感知服务质量、期望服务质量及服务质量满意度。结果:感知服务水平与期望服务水平的差值为?7.91,低于0分,代表老年人整体上对养老机构的服务质量不满意。老年人的婚姻状况(β = ?0.325, P 【0.01)、居住情况(β = ?0.187, P = 0.013)及领悟社会支持水平(β = 0.440, P 【0.001)是服务质量评价的影响因素,其他因素无统计学意义。结论:老年人整体上对养老机构的服务质量不满意,婚姻状况、居住情况及领悟社会支持水平是服务质量评价的影响因素。展开更多
Fluid flow in an internal combustion engine presents one of the most challenging fluid dynamics problems to model. This is because the flow is associated with large density variations. So, a detailed understanding of ...Fluid flow in an internal combustion engine presents one of the most challenging fluid dynamics problems to model. This is because the flow is associated with large density variations. So, a detailed understanding of the flow and combustion processes is required to improve performance and reduce emissions without compromising fuel economy. The simulation carried out in the present work to model DI diesel engine with bowl in piston for better understanding of the in cylinder gas motion with details of the combustion process that are essential in evaluating the effects of ingesting synthetic atmosphere on engine performance. This is needed for the course of developing a non-air recycle diesel with exhaust management system [1]. A simulation was carried out using computational fluid dynamics (CFD) code FLU- ENT. The turbulence and combustion processes are modeled with sufficient generality to include spray formation, delay period, chemical kinetics and on set of ignition. Results from the simulation compared well with that of experimental results. The model proved invaluable in obtaining details of the in cylinder flow patterns, combustion process and combustion species during the engine cycle. The results show that the model over predicting the maximum pressure peak by 6%, (p-θ), (p-v) diagrams for different engine loads are predicted. Also the study shows other engine parameters captured by the simulation such as engine emissions, fuel mass fraction, indicated gross work, ignition delay period and heat release rate.展开更多
At home and broad, more wind power is being installed in electricity markets, the influence brought by wind power become more important on power system stability, especially the fluctuation, the uncertainty in wind po...At home and broad, more wind power is being installed in electricity markets, the influence brought by wind power become more important on power system stability, especially the fluctuation, the uncertainty in wind power production and multi-time scale of the wind. In order to forecast ramp events before the power system encountering failure, so that the operator can adopt some limited controlling strategy. This paper introduces the present status of the wind power ramp prediction at home and abroad. And it gives out four kinds of definitions of ramp events, which are used by many scholars, then provides various forecasting error algorithm. In the aspect of prediction models, it comes up with physical models and statistical models, and enumerates various examples of different models. Finally, it prospects the tendency of the model improvement about the wind power ramp events forecasting, which would be significant for ramp research.展开更多
The initial oxidation behavior of Ni-6.5Co-17.8Cr-3.7Al-0.5Y alloy is investigated at 800°C-1000°C. X-ray diffraction results show that the dominant Cr2O3 phase and secondary α-Al2O3 and NiO phases are obse...The initial oxidation behavior of Ni-6.5Co-17.8Cr-3.7Al-0.5Y alloy is investigated at 800°C-1000°C. X-ray diffraction results show that the dominant Cr2O3 phase and secondary α-Al2O3 and NiO phases are observed on the surface of samples at all initial stages (oxidized for 16 hours). YAlO3 and θ-Al2O3 can only be detected at low temperature (800°C) while the spinel NiCr2O4 is only observed at 900°C and 1000°C. Though the growth rates of α-Al2O3 and Cr2O3 are comparable at 900°C, the former becomes much lower than the latter when the temperature changes to 1000°C. Scanning electron microscopy (SEM) images show that the α-Al2O3 grows from some irregular ditches in the chromia scale at 900°C. However, cracking and spalling are more serious at 1000°C without α-Al2O3-grown-ditches, which is in accordance with the growth rates of these oxides at different temperatures. The cracking can be explained by the results of Raman determination which indicate that the stress on the surface of specimen oxidized at 1000°C is higher than that at 900°C. Owing to this condition, a preoxidation treatment on the NiCoCrAlY alloy for 16 hours is prepared at 900°C, and then thermal cycling oxidation test is conducted at 1000°C for 200 hours. The result indicates that the initial preoxidation treatment at 900°C improves the oxidation resistance of alloy at 1000°C.展开更多
A kinetic study of biogas production from Urban Solid Waste (USW) generated in Dar es Salaam city (Tanzania) is presented. An experimental bioreactor simulating mesophilic conditions of most USW landfills was develope...A kinetic study of biogas production from Urban Solid Waste (USW) generated in Dar es Salaam city (Tanzania) is presented. An experimental bioreactor simulating mesophilic conditions of most USW landfills was developed. The goal of the study was to generate the kinetic order of reaction with respect to biodegradable organic waste and use it to model biogas production from food residues mixed with fruit waste. Anaerobic biodegradation was employed under temperature range of 28℃ - 38℃. The main controls were leachate recirculation and pH adjustments to minimize acid inhibitory effects and accelerate waste biodegradation. The experimental setup comprised of three sets of bioreactors. A biodegradation rate law in differential form was proposed and the numerical values of kinetic order and rate constant were determined using initial rate method as 0.994 and 0.3093 mol0.006·day-1, respectively. Results obtained were consistent with that found in literature and model predictions were in reasonable agreement with experimental data.展开更多
New advances within the recently rediscovered field of Compressed Sensing (CS) have opened for a great variety of new possibilities in the field of image reconstruction and more specifically in medical image reconstru...New advances within the recently rediscovered field of Compressed Sensing (CS) have opened for a great variety of new possibilities in the field of image reconstruction and more specifically in medical image reconstruction. In this work, a new approach using a CS-based algorithm is proposed and used in order to solve limited-angle problems (LAPs), like the ones that typically occur in computed tomography or electron microscope. This approach is based on a variant of the Robbins-Monro stochastic approximation procedure, developed by Egaziarian, using regularization by a spatially adaptive filter. This proposal consists on filling the gaps of missing or unobserved data with random noise and enabling a spatially adaptive denoising filter to regularize the data and reveal the underlying topology. This method was tested on different 3D transmission electron microscope datasets that presented different missing data artifacts (e.g, wedge or cone shape). The test results show a great potential for solving LAPs using the proposed technique.展开更多
This paper focuses on model development for computer analysis of the thermal behavior of an externally driven spindle. The aim of the developed model is to enable efficient quantitative estimation of the thermal chara...This paper focuses on model development for computer analysis of the thermal behavior of an externally driven spindle. The aim of the developed model is to enable efficient quantitative estimation of the thermal characteristics of the main spindle unit in an early stage of the development process. The presented work includes an experimental validation of the simulation model using a custom-built test rig. Specifically, the effects of the heat generated in the bearings and the heat flux from the bearing to the adjacent spindle system elements are investigated. Simulation and experimental results are compared and demonstrate good accordance. The proposed model is a useful, efficient and validated tool for quantitative simulation of thermal behavior of a main spindle system.展开更多
Active noise controls are used in a wide field of applications to cancel out unwanted surrounding noise. Control systems based on the feedback structure however have the disadvantage that they may become unstable duri...Active noise controls are used in a wide field of applications to cancel out unwanted surrounding noise. Control systems based on the feedback structure however have the disadvantage that they may become unstable during run-time due to changes in the control path—in this context including the listener’s ear. Especially when applied to active noise cancellation (ANC) headphones, the risk of instability is associated with the risk of harmful influence on the listener’s ear, which is exposed to the speaker in striking distance. This paper discusses several methods to enable the analysis of a feedback ANC system during run-time to immediately detect instability. Finally, a solution is proposed, which identifies the open loop behavior parametrically by means of an adaptive filter to subsequently evaluate the coefficients regarding stability.展开更多
Systematic, preventive and corrective maintenance is essential for existing buildings in order to retain their original functionality and appearance and satisfy the needs of the users. Essential input for maintenance ...Systematic, preventive and corrective maintenance is essential for existing buildings in order to retain their original functionality and appearance and satisfy the needs of the users. Essential input for maintenance is information about buildings. This paper discusses the assessment of the advantages and limitations of using photogrammetry and a low-cost 3D scanner to collect information from existing buildings and create, through integrative software, BIM models as information systems to support the operation and maintenance functions. Also, these methodologies were compared with one another as well as with a manual information survey conducted at a university campus. The main conclusion is that a combination of methods must be used to obtain geometrical information on existing buildings for their operation and maintenance functions, depending on which ones are the most suitable for the case at hand.展开更多
With autotrophic microalgae cultivation,?we can feed back the CO2?content of process streams and we can get lots of valuable organic compounds, among others biofuel components. For the production of energy source,we m...With autotrophic microalgae cultivation,?we can feed back the CO2?content of process streams and we can get lots of valuable organic compounds, among others biofuel components. For the production of energy source,we must reckon with the energy balance of the whole process. Densification and processing of microalgae can consume 50% - 70% of the energy that can be extracted from the cells,?therefore the cultivation should use such a little energy as it possible. In closed cultivation systems,?there are three main energy intensive steps: artificial illumination, dissolution of gas compounds and mixing. We have carried out our measurements in our lab-scale screening photobioreactor system for the investigation of the most energy effective program for aeration. We have found the aeration program considerable solution for lower energy consumption in?algae cultivation.展开更多
文摘目的:分析养老机构服务质量的现状及影响因素。方法:采取便利取样法对深圳市养老机构217位老年人进行问卷调查,采用SERVQL量表评估老年人的感知服务质量、期望服务质量及服务质量满意度。结果:感知服务水平与期望服务水平的差值为?7.91,低于0分,代表老年人整体上对养老机构的服务质量不满意。老年人的婚姻状况(β = ?0.325, P 【0.01)、居住情况(β = ?0.187, P = 0.013)及领悟社会支持水平(β = 0.440, P 【0.001)是服务质量评价的影响因素,其他因素无统计学意义。结论:老年人整体上对养老机构的服务质量不满意,婚姻状况、居住情况及领悟社会支持水平是服务质量评价的影响因素。
文摘Fluid flow in an internal combustion engine presents one of the most challenging fluid dynamics problems to model. This is because the flow is associated with large density variations. So, a detailed understanding of the flow and combustion processes is required to improve performance and reduce emissions without compromising fuel economy. The simulation carried out in the present work to model DI diesel engine with bowl in piston for better understanding of the in cylinder gas motion with details of the combustion process that are essential in evaluating the effects of ingesting synthetic atmosphere on engine performance. This is needed for the course of developing a non-air recycle diesel with exhaust management system [1]. A simulation was carried out using computational fluid dynamics (CFD) code FLU- ENT. The turbulence and combustion processes are modeled with sufficient generality to include spray formation, delay period, chemical kinetics and on set of ignition. Results from the simulation compared well with that of experimental results. The model proved invaluable in obtaining details of the in cylinder flow patterns, combustion process and combustion species during the engine cycle. The results show that the model over predicting the maximum pressure peak by 6%, (p-θ), (p-v) diagrams for different engine loads are predicted. Also the study shows other engine parameters captured by the simulation such as engine emissions, fuel mass fraction, indicated gross work, ignition delay period and heat release rate.
文摘At home and broad, more wind power is being installed in electricity markets, the influence brought by wind power become more important on power system stability, especially the fluctuation, the uncertainty in wind power production and multi-time scale of the wind. In order to forecast ramp events before the power system encountering failure, so that the operator can adopt some limited controlling strategy. This paper introduces the present status of the wind power ramp prediction at home and abroad. And it gives out four kinds of definitions of ramp events, which are used by many scholars, then provides various forecasting error algorithm. In the aspect of prediction models, it comes up with physical models and statistical models, and enumerates various examples of different models. Finally, it prospects the tendency of the model improvement about the wind power ramp events forecasting, which would be significant for ramp research.
文摘The initial oxidation behavior of Ni-6.5Co-17.8Cr-3.7Al-0.5Y alloy is investigated at 800°C-1000°C. X-ray diffraction results show that the dominant Cr2O3 phase and secondary α-Al2O3 and NiO phases are observed on the surface of samples at all initial stages (oxidized for 16 hours). YAlO3 and θ-Al2O3 can only be detected at low temperature (800°C) while the spinel NiCr2O4 is only observed at 900°C and 1000°C. Though the growth rates of α-Al2O3 and Cr2O3 are comparable at 900°C, the former becomes much lower than the latter when the temperature changes to 1000°C. Scanning electron microscopy (SEM) images show that the α-Al2O3 grows from some irregular ditches in the chromia scale at 900°C. However, cracking and spalling are more serious at 1000°C without α-Al2O3-grown-ditches, which is in accordance with the growth rates of these oxides at different temperatures. The cracking can be explained by the results of Raman determination which indicate that the stress on the surface of specimen oxidized at 1000°C is higher than that at 900°C. Owing to this condition, a preoxidation treatment on the NiCoCrAlY alloy for 16 hours is prepared at 900°C, and then thermal cycling oxidation test is conducted at 1000°C for 200 hours. The result indicates that the initial preoxidation treatment at 900°C improves the oxidation resistance of alloy at 1000°C.
文摘A kinetic study of biogas production from Urban Solid Waste (USW) generated in Dar es Salaam city (Tanzania) is presented. An experimental bioreactor simulating mesophilic conditions of most USW landfills was developed. The goal of the study was to generate the kinetic order of reaction with respect to biodegradable organic waste and use it to model biogas production from food residues mixed with fruit waste. Anaerobic biodegradation was employed under temperature range of 28℃ - 38℃. The main controls were leachate recirculation and pH adjustments to minimize acid inhibitory effects and accelerate waste biodegradation. The experimental setup comprised of three sets of bioreactors. A biodegradation rate law in differential form was proposed and the numerical values of kinetic order and rate constant were determined using initial rate method as 0.994 and 0.3093 mol0.006·day-1, respectively. Results obtained were consistent with that found in literature and model predictions were in reasonable agreement with experimental data.
文摘New advances within the recently rediscovered field of Compressed Sensing (CS) have opened for a great variety of new possibilities in the field of image reconstruction and more specifically in medical image reconstruction. In this work, a new approach using a CS-based algorithm is proposed and used in order to solve limited-angle problems (LAPs), like the ones that typically occur in computed tomography or electron microscope. This approach is based on a variant of the Robbins-Monro stochastic approximation procedure, developed by Egaziarian, using regularization by a spatially adaptive filter. This proposal consists on filling the gaps of missing or unobserved data with random noise and enabling a spatially adaptive denoising filter to regularize the data and reveal the underlying topology. This method was tested on different 3D transmission electron microscope datasets that presented different missing data artifacts (e.g, wedge or cone shape). The test results show a great potential for solving LAPs using the proposed technique.
文摘This paper focuses on model development for computer analysis of the thermal behavior of an externally driven spindle. The aim of the developed model is to enable efficient quantitative estimation of the thermal characteristics of the main spindle unit in an early stage of the development process. The presented work includes an experimental validation of the simulation model using a custom-built test rig. Specifically, the effects of the heat generated in the bearings and the heat flux from the bearing to the adjacent spindle system elements are investigated. Simulation and experimental results are compared and demonstrate good accordance. The proposed model is a useful, efficient and validated tool for quantitative simulation of thermal behavior of a main spindle system.
文摘Active noise controls are used in a wide field of applications to cancel out unwanted surrounding noise. Control systems based on the feedback structure however have the disadvantage that they may become unstable during run-time due to changes in the control path—in this context including the listener’s ear. Especially when applied to active noise cancellation (ANC) headphones, the risk of instability is associated with the risk of harmful influence on the listener’s ear, which is exposed to the speaker in striking distance. This paper discusses several methods to enable the analysis of a feedback ANC system during run-time to immediately detect instability. Finally, a solution is proposed, which identifies the open loop behavior parametrically by means of an adaptive filter to subsequently evaluate the coefficients regarding stability.
文摘Systematic, preventive and corrective maintenance is essential for existing buildings in order to retain their original functionality and appearance and satisfy the needs of the users. Essential input for maintenance is information about buildings. This paper discusses the assessment of the advantages and limitations of using photogrammetry and a low-cost 3D scanner to collect information from existing buildings and create, through integrative software, BIM models as information systems to support the operation and maintenance functions. Also, these methodologies were compared with one another as well as with a manual information survey conducted at a university campus. The main conclusion is that a combination of methods must be used to obtain geometrical information on existing buildings for their operation and maintenance functions, depending on which ones are the most suitable for the case at hand.
文摘With autotrophic microalgae cultivation,?we can feed back the CO2?content of process streams and we can get lots of valuable organic compounds, among others biofuel components. For the production of energy source,we must reckon with the energy balance of the whole process. Densification and processing of microalgae can consume 50% - 70% of the energy that can be extracted from the cells,?therefore the cultivation should use such a little energy as it possible. In closed cultivation systems,?there are three main energy intensive steps: artificial illumination, dissolution of gas compounds and mixing. We have carried out our measurements in our lab-scale screening photobioreactor system for the investigation of the most energy effective program for aeration. We have found the aeration program considerable solution for lower energy consumption in?algae cultivation.