The vibration signals of rolling element bearing are produced by a combination of periodic and random processes due to the machine’s rotation cycle and interaction with the real world. The combination of such compone...The vibration signals of rolling element bearing are produced by a combination of periodic and random processes due to the machine’s rotation cycle and interaction with the real world. The combination of such components can give rise to signals, which have periodically time-varying ensemble statistical and are best considered as cyclostationary. When the early fault occurs, the background noise is very heavy, it is difficult to disclose the latent periodic components successfully using cyclostationary analysis alone. In this paper the degree of cyclostationarity is combined with wavelet filtering for detection of rolling element bearing early faults. Using the proposed entropy minimization rule. The parameters of the wavelet filter are optimized. This method is shown to be effective in detecting rolling element bearing early fault when cyclostationary analysis by itself fails.展开更多
In conventional source-filter models, voiced and unvoiced components were considered independently. However, in practice it was difficult to separate the source into two parts. An actual source consists of a mixture o...In conventional source-filter models, voiced and unvoiced components were considered independently. However, in practice it was difficult to separate the source into two parts. An actual source consists of a mixture of two sources and the ratio varies according to the content or the intention of speaker. It had been investigated to separate the voiced and unvoiced components for different source models. Source signals were modeled based on the residual signal measured from inverse filtering. Three different source models were assumed. The parameters of each model were optimized for the original speech signal using a genetic algorithm. The resulting parameters were compared in terms of the mel-cepstral distance to the original signal, the spectrogram and the spectral envelope from the synthesized signal. The optimization method achieves an improvement of 15% for the Klatt model, but there is little improvement in the modified residual case.展开更多
A new in situ treatment technique was being utilized on a part of the Dorfweiher landfill in Konstanz, Germany to reduce the aftercare period. From 2010 to 2012, the landfill was aerated intermittently with low pressu...A new in situ treatment technique was being utilized on a part of the Dorfweiher landfill in Konstanz, Germany to reduce the aftercare period. From 2010 to 2012, the landfill was aerated intermittently with low pressure. Outgoing air was treated passively in an open biofilter which covers the landfill surface. The landfill was aerated by means of 80 air injection wells arranged area-wide in a 10 m grid. An elaborate measuring process and technological controls are being utilized in the pilot scheme. The data collected offer interesting insights about the processes during aeration, allowing optimization of the aeration strategy depending on changes of the conditions in the landfill. During the three-year aeration phase, conditions have changed inside the landfill section in various ways. In numerous zones of the landfill body, the aeration caused aerobic conditions with a decline of methane production. Accelerated settlings are measured up to 11%. The effects of the aerobic stabilization on the landfill are evaluated in a two-year monitoring phase started in 2013.展开更多
Changes in the regulatory requirements and the forthcoming Disinfectant/Disinfection By-Products （D/DBP） Rule will require that drinking water treatment facilities be operated to achieve maximum removals of particle...Changes in the regulatory requirements and the forthcoming Disinfectant/Disinfection By-Products （D/DBP） Rule will require that drinking water treatment facilities be operated to achieve maximum removals of particles and disinfectant tolerant microorganisms as well as natural organic matter （NOM）. For drinking water production, the use of membrane filtration processes such as microfiltration and ultrafiltration （MF/UF） alone to satisfy the turbidity, particle and microorganism removal a requirement of the surface water treatment regulation （SWTR） is not enough. MF/UF treatment processes can achieve only nominal （10 percent） removal of disinfection by-products （DBP） precursors （James, et al., 1995）. On the other hand, too fast fouling can make the filtration processes more difficult to carry on. To solve these problems, many authors have been interested in installing coagulation pretreatment before membrane filtration to improve membrane performance. However, previous studies reported conflicting results. Some supported the effectiveness of coagulation pretreatment, while others contended that coagulation aggravated membrane performance. This research aims to identify the effects of coagulation pretreatment on membrane filtration through a pilot study using PVDF membrane in combination with analyzing the rationale of coagulation. Another objective of this research was to evaluate the different impacts on membrane performance of using different membrane modules （the submerged module and pressured module）. The results showed that coagulation pretreatment greatly improved the membrane performance, extending the filtration time as well as reducing the permeated organic level, and that the submerged module is much more efficient than the pressured module.展开更多
The aim of this new study is to investigate the ability of using crushed plastic solid wastes in water filtration by using a pilot plant. Two sets of filters were used. The first set represents mono media filters. The...The aim of this new study is to investigate the ability of using crushed plastic solid wastes in water filtration by using a pilot plant. Two sets of filters were used. The first set represents mono media filters. The first filter is a sand media with effective size of 0.65 mm and the others three are plastic media with different grain sizes. The second set represents dual media filters with different depths, the filters were made to operate with the same effective size （0.6-1.0 mm）. These filters were subjected to the same operating conditions of filtration rates and infiuent turbidity. The filters were operated at rates of 5, 7.5, 10, and 12.5 m/h in order to find the optimum filtration velocity with influent turbidity ranged between 7 and l0 NTU （nephelometric turbidity unit）. The results indicated that the single plastic filters and the dual filters produced water of the same high quality as the sand filter. Plastic filters were slower in the development of head losses by about of 8%-78% less and they have longer running time than the sand filter, while the dual filters were slower in the development of head losses by about of 14%-16% and they have longer running time by about of 12%-40% than the sand filter.展开更多
The application of single nanofiltration （NF） and sequential filtration of microfiltration （MF） and NF for the concentration of vinasse were studied. Filtration experiments were performed at 60 ℃, 500 rpm and dif...The application of single nanofiltration （NF） and sequential filtration of microfiltration （MF） and NF for the concentration of vinasse were studied. Filtration experiments were performed at 60 ℃, 500 rpm and different transmembrane pressures using four commercial membranes： MF, PVDF 0.2 μm; NF, PES 300, 500 and 1000 Da. The process effectiveness was evaluated through the permeate flux and the total solids （TS） concentration in the retentate. Because the retention of TS and permeate fluxes were very similar for MF, PVDF-0.2 membrane at 0.10 MPa was selected because of its lower power consumption. The best conditions tested for NF were the following： PES-1000 at 3.50 MPa with a flux of 183.2 kg/m^2 h at a volume reduction factor （VRF） of 2, under which 68% of solids were retained. For the MF ＋ NF, a PES-1000 at 3.50 MPa was selected because a higher permeate flux was achieved at a VRF of 4, and PES-500 at 3.50 MPa because a higher retention of TS was achieved compared to the other experiments. A single NF resulted in a retentate concentration that was almost twice as high as the hybrid MF and NF process, allowing reduced costs in its transportation from distilleries to distant areas.展开更多
In this paper, we present Real-Time Flow Filter (RTFF) -a system that adopts a middle ground between coarse-grained volume anomaly detection and deep packet inspection. RTFF was designed with the goal of scaling to hi...In this paper, we present Real-Time Flow Filter (RTFF) -a system that adopts a middle ground between coarse-grained volume anomaly detection and deep packet inspection. RTFF was designed with the goal of scaling to high volume data feeds that are common in large Tier-1 ISP networks and providing rich, timely information on observed attacks. It is a software solution that is designed to run on off-the-shelf hardware platforms and incorporates a scalable data processing architecture along with lightweight analysis algorithms that make it suitable for deployment in large networks. RTFF also makes use of state of the art machine learning algorithms to construct attack models that can be used to detect as well as predict attacks.展开更多
Large-eddy simulation developments and validations are presented for an improved simulation of turbulent internal flows. Numerical methods are proposed according to two competing criteria： numerical qualities （preci...Large-eddy simulation developments and validations are presented for an improved simulation of turbulent internal flows. Numerical methods are proposed according to two competing criteria： numerical qualities （precision and spectral characteristics）, and adaptability to complex configurations. First, methods are tested on academic test-cases, in order to abridge with fundamental studies. Consistent results are obtained using adaptable finite volume method, with higher order advection fluxes, implicit grid filtering and ＂low-cost＂ shear-improved Smagorinsky model. This analysis particularly focuses on mean flow, fluctuations, two-point correlations and spectra. Moreover, it is shown that exponential averaging is a promising tool for LES implementation in complex geometry with deterministic unsteadiness. Finally, adaptability of the method is demonstrated by application to a configuration representative of blade-tip clearance flow in a turbomachine.展开更多
Human glycerol channel aquaporin 7(AQP7)conducts glycerol release from adipocyte and enters the cells in pancreatic islets,muscles,and kidney tubules,and thus regulates glycerol metabolism in those tissues.Compared wi...Human glycerol channel aquaporin 7(AQP7)conducts glycerol release from adipocyte and enters the cells in pancreatic islets,muscles,and kidney tubules,and thus regulates glycerol metabolism in those tissues.Compared with other human aquaglyceroporins,AQP7 shows a less conserved‘‘NPA”motif in the center cavity and a pair of aromatic residues at Ar/R selectivity filter.To understand the structural basis for the glycerol conductance,we crystallized the human AQP7 and determined the structure at 3.7Å.A substrate binding pocket was found near the Ar/R filter where a glycerol molecule is bound and stabilized by R229.Glycerol uptake assay on human AQP7 as well as AQP3 and AQP10 demonstrated strong glycerol transportation activities at the physiological condition.The human AQP7 structure,in combination with the molecular dynamics simulation thereon,reveals a fully closed conformation with its permeation pathway strictly confined by the Ar/R filter at the exoplasmic side and the gate at the cytoplasmic side,and the binding of glycerol at the Ar/R filter plays a critical role in controlling the glycerol flux by driving the dislocation of the residues at narrowest parts of glycerol pathway in AQP7.展开更多
基金National Natural Science Foundation ofChina(No.50175068) and the Key Project sup-ported by National Natural Science Foundationof China(No.50335030)
文摘The vibration signals of rolling element bearing are produced by a combination of periodic and random processes due to the machine’s rotation cycle and interaction with the real world. The combination of such components can give rise to signals, which have periodically time-varying ensemble statistical and are best considered as cyclostationary. When the early fault occurs, the background noise is very heavy, it is difficult to disclose the latent periodic components successfully using cyclostationary analysis alone. In this paper the degree of cyclostationarity is combined with wavelet filtering for detection of rolling element bearing early faults. Using the proposed entropy minimization rule. The parameters of the wavelet filter are optimized. This method is shown to be effective in detecting rolling element bearing early fault when cyclostationary analysis by itself fails.
基金supported by the Second Stage of Brain Korea 21 Projects
文摘In conventional source-filter models, voiced and unvoiced components were considered independently. However, in practice it was difficult to separate the source into two parts. An actual source consists of a mixture of two sources and the ratio varies according to the content or the intention of speaker. It had been investigated to separate the voiced and unvoiced components for different source models. Source signals were modeled based on the residual signal measured from inverse filtering. Three different source models were assumed. The parameters of each model were optimized for the original speech signal using a genetic algorithm. The resulting parameters were compared in terms of the mel-cepstral distance to the original signal, the spectrogram and the spectral envelope from the synthesized signal. The optimization method achieves an improvement of 15% for the Klatt model, but there is little improvement in the modified residual case.
文摘A new in situ treatment technique was being utilized on a part of the Dorfweiher landfill in Konstanz, Germany to reduce the aftercare period. From 2010 to 2012, the landfill was aerated intermittently with low pressure. Outgoing air was treated passively in an open biofilter which covers the landfill surface. The landfill was aerated by means of 80 air injection wells arranged area-wide in a 10 m grid. An elaborate measuring process and technological controls are being utilized in the pilot scheme. The data collected offer interesting insights about the processes during aeration, allowing optimization of the aeration strategy depending on changes of the conditions in the landfill. During the three-year aeration phase, conditions have changed inside the landfill section in various ways. In numerous zones of the landfill body, the aeration caused aerobic conditions with a decline of methane production. Accelerated settlings are measured up to 11%. The effects of the aerobic stabilization on the landfill are evaluated in a two-year monitoring phase started in 2013.
文摘Changes in the regulatory requirements and the forthcoming Disinfectant/Disinfection By-Products （D/DBP） Rule will require that drinking water treatment facilities be operated to achieve maximum removals of particles and disinfectant tolerant microorganisms as well as natural organic matter （NOM）. For drinking water production, the use of membrane filtration processes such as microfiltration and ultrafiltration （MF/UF） alone to satisfy the turbidity, particle and microorganism removal a requirement of the surface water treatment regulation （SWTR） is not enough. MF/UF treatment processes can achieve only nominal （10 percent） removal of disinfection by-products （DBP） precursors （James, et al., 1995）. On the other hand, too fast fouling can make the filtration processes more difficult to carry on. To solve these problems, many authors have been interested in installing coagulation pretreatment before membrane filtration to improve membrane performance. However, previous studies reported conflicting results. Some supported the effectiveness of coagulation pretreatment, while others contended that coagulation aggravated membrane performance. This research aims to identify the effects of coagulation pretreatment on membrane filtration through a pilot study using PVDF membrane in combination with analyzing the rationale of coagulation. Another objective of this research was to evaluate the different impacts on membrane performance of using different membrane modules （the submerged module and pressured module）. The results showed that coagulation pretreatment greatly improved the membrane performance, extending the filtration time as well as reducing the permeated organic level, and that the submerged module is much more efficient than the pressured module.
文摘The aim of this new study is to investigate the ability of using crushed plastic solid wastes in water filtration by using a pilot plant. Two sets of filters were used. The first set represents mono media filters. The first filter is a sand media with effective size of 0.65 mm and the others three are plastic media with different grain sizes. The second set represents dual media filters with different depths, the filters were made to operate with the same effective size （0.6-1.0 mm）. These filters were subjected to the same operating conditions of filtration rates and infiuent turbidity. The filters were operated at rates of 5, 7.5, 10, and 12.5 m/h in order to find the optimum filtration velocity with influent turbidity ranged between 7 and l0 NTU （nephelometric turbidity unit）. The results indicated that the single plastic filters and the dual filters produced water of the same high quality as the sand filter. Plastic filters were slower in the development of head losses by about of 8%-78% less and they have longer running time than the sand filter, while the dual filters were slower in the development of head losses by about of 14%-16% and they have longer running time by about of 12%-40% than the sand filter.
文摘The application of single nanofiltration （NF） and sequential filtration of microfiltration （MF） and NF for the concentration of vinasse were studied. Filtration experiments were performed at 60 ℃, 500 rpm and different transmembrane pressures using four commercial membranes： MF, PVDF 0.2 μm; NF, PES 300, 500 and 1000 Da. The process effectiveness was evaluated through the permeate flux and the total solids （TS） concentration in the retentate. Because the retention of TS and permeate fluxes were very similar for MF, PVDF-0.2 membrane at 0.10 MPa was selected because of its lower power consumption. The best conditions tested for NF were the following： PES-1000 at 3.50 MPa with a flux of 183.2 kg/m^2 h at a volume reduction factor （VRF） of 2, under which 68% of solids were retained. For the MF ＋ NF, a PES-1000 at 3.50 MPa was selected because a higher permeate flux was achieved at a VRF of 4, and PES-500 at 3.50 MPa because a higher retention of TS was achieved compared to the other experiments. A single NF resulted in a retentate concentration that was almost twice as high as the hybrid MF and NF process, allowing reduced costs in its transportation from distilleries to distant areas.
文摘In this paper, we present Real-Time Flow Filter (RTFF) -a system that adopts a middle ground between coarse-grained volume anomaly detection and deep packet inspection. RTFF was designed with the goal of scaling to high volume data feeds that are common in large Tier-1 ISP networks and providing rich, timely information on observed attacks. It is a software solution that is designed to run on off-the-shelf hardware platforms and incorporates a scalable data processing architecture along with lightweight analysis algorithms that make it suitable for deployment in large networks. RTFF also makes use of state of the art machine learning algorithms to construct attack models that can be used to detect as well as predict attacks.
文摘Large-eddy simulation developments and validations are presented for an improved simulation of turbulent internal flows. Numerical methods are proposed according to two competing criteria： numerical qualities （precision and spectral characteristics）, and adaptability to complex configurations. First, methods are tested on academic test-cases, in order to abridge with fundamental studies. Consistent results are obtained using adaptable finite volume method, with higher order advection fluxes, implicit grid filtering and ＂low-cost＂ shear-improved Smagorinsky model. This analysis particularly focuses on mean flow, fluctuations, two-point correlations and spectra. Moreover, it is shown that exponential averaging is a promising tool for LES implementation in complex geometry with deterministic unsteadiness. Finally, adaptability of the method is demonstrated by application to a configuration representative of blade-tip clearance flow in a turbomachine.
基金the National Key Research and Development Program of China(2018YFC1004704 and 2017YFC1001303)the National Natural Science Foundation of China(U1632132,31670849,and 91853206)+3 种基金the Shanghai Science and Technology Committee(20S11902000)the SHIPM-pi fund(JY201804)the SHIPM-sigma fund(2018JC002)from Shanghai Institute of Precision Medicine,Ninth People’s Hospital Shanghai Jiao Tong University School of Medicinethe Innovative Research Team of Highlevel Local Universities in Shanghai(SSMU-ZLCX20180600)。
文摘Human glycerol channel aquaporin 7(AQP7)conducts glycerol release from adipocyte and enters the cells in pancreatic islets,muscles,and kidney tubules,and thus regulates glycerol metabolism in those tissues.Compared with other human aquaglyceroporins,AQP7 shows a less conserved‘‘NPA”motif in the center cavity and a pair of aromatic residues at Ar/R selectivity filter.To understand the structural basis for the glycerol conductance,we crystallized the human AQP7 and determined the structure at 3.7Å.A substrate binding pocket was found near the Ar/R filter where a glycerol molecule is bound and stabilized by R229.Glycerol uptake assay on human AQP7 as well as AQP3 and AQP10 demonstrated strong glycerol transportation activities at the physiological condition.The human AQP7 structure,in combination with the molecular dynamics simulation thereon,reveals a fully closed conformation with its permeation pathway strictly confined by the Ar/R filter at the exoplasmic side and the gate at the cytoplasmic side,and the binding of glycerol at the Ar/R filter plays a critical role in controlling the glycerol flux by driving the dislocation of the residues at narrowest parts of glycerol pathway in AQP7.
