A unitized regenerative fuel cell(URFC)is a device that may function reversibly as either a fuel cell(FC)or water elec-trolysis(WE).An important component of this device is the Membrane electrode assembly(MEA).Therefo...A unitized regenerative fuel cell(URFC)is a device that may function reversibly as either a fuel cell(FC)or water elec-trolysis(WE).An important component of this device is the Membrane electrode assembly(MEA).Therefore,this study aimed to compare the performance outcomes of MEA using electrodes with single and three catalyst layers.This study measured Electrochemical Surface Area(ECSA),Electrochemical Impedance Spectroscopy(EIS),X-ray Diffraction analysis(XRD),and X-ray Fluorescence(XRF).Furthermore,the round-trip efficiency(RTE)of the MEA,as w ell as the performance in FC and WE mode,was measured.In comparison,The ECSA values of Pt-Ru/C and Pt/C with three catalyst layers were higher than the single catalyst layer.This result was supported by electrode characterization data for XRD and XRF.The respective electrical conductivity values of Pt-Ru/C and Pt/C with three catalyst layers are also higher than the single cata-lyst layer,and the performance of URFC using MEA with three catalyst layers has the highest value of RTE among the MEA performances of URFC,which is 100%at a current density of 4 mA·cm-2.展开更多
A research has been carried out to investigate the mechanical properties of composites made by hybridizing sugar palm fibre （Arenga pinnata） with glass fibre into an unsaturated polyester matrix. Hybrid composites o...A research has been carried out to investigate the mechanical properties of composites made by hybridizing sugar palm fibre （Arenga pinnata） with glass fibre into an unsaturated polyester matrix. Hybrid composites of glass/sugar palm fibre were fabricated in different weight ratios of strand mat glass fibres ： sugar palm fibres 4：0, 4：1, 4：2, 4：3, 4：4, and 0：4. The hybrid effects of glass and sugar palm fibre on tensile, flexural and impact properties of the composites were evaluated according to ASTM D5083, ASTM D790 and ASTM D256 respectively. Results have been established that properties of hybrid glass/sugar palm composites such as tensile strength, tensile modulus, elongation at break, toughness, flexural strength, flexural modulus and impact strength are a function of fibre content. The failure mechanism and the adhesion between fibres/matrix were studied by observing the scanning electron micrographs of impact fracture samples. In general, the incorporation of both fibres into unsaturated polyester matrix shows a regular trend of increase in the mechanical properties.展开更多
To evaluate the long-term consequence of repetitive mild traumatic brain injury （mTBI） on bone, mTBI was induced in 10-week-old female C57BL/6J mice using a weight drop model, once per day for 4 consecutive days at ...To evaluate the long-term consequence of repetitive mild traumatic brain injury （mTBI） on bone, mTBI was induced in 10-week-old female C57BL/6J mice using a weight drop model, once per day for 4 consecutive days at different drop heights （0.5, 1 and 1.5 m） and the skeletal phenotype was evaluated at different time points after the impact. In vivo micro-CT （μ-CT） analysis of the tibial metaphysis at 2, 8 and 12 weeks after the impact revealed a 5%-32% reduction in trabecular bone mass. Histomorphometric analyses showed a reduced bone formation rate in the secondary spongiosa ofl.5 m impacted mice at 12 weeks post impact. Apparent modulus （bone strength）, was reduced by 30% （P 〈 0.05） at the proximal tibial metaphysis in the 1.5 m drop height group at 2 and 8 weeks post impact. Ex vivo μ-CT analysis of the fifth lumbar vertebra revealed a significant reduction in trabecular bone mass at 12 weeks of age in all three drop height groups. Serum levels of osteocalcin were decreased by 22%, 15%, and 19% in the 0.5, 1.0 and 1.5 m drop height groups, respectively, at 2 weeks post impact. Serum IGF-I levels were reduced by 18%-32% in mTBI mice compared to control mice at 2 weeks post impact. Serum osteocalcin and IGF-I levels correlated with trabecular BV/TV （r2 = 0.14 and 0.16, P 〈 0.05）. In conclusion, repetitive mTBI exerts significant negative effects on the trabecular bone microarchitecture and bone mechanical properties by influencing osteoblast function via reduced endocrine IGF-I actions.展开更多
Analytical solutions of temperature distributions and the Nusselt numbers in forced convection are reported for flow through infinitely long parallel plates, where the upper plate moves in the flow direction with cons...Analytical solutions of temperature distributions and the Nusselt numbers in forced convection are reported for flow through infinitely long parallel plates, where the upper plate moves in the flow direction with constant velocity and the lower plate is kept stationary. The flow is assumed to be laminar, both hydro-dynamically and thermally fully developed, taking into account the effect of viscous dissipation of the flowing fluid. Both the plates being kept at specified and at different constant heat fluxes are considered as thermal boundary conditions. The solutions obtained from energy equation are in terms of Brinkman number, dimensionless velocity and heat flux ratio. These parameters greatly influence and give complete understanding on heat transfer rates that has potentials for designing and analyzing energy equipment and processes.展开更多
Large displacement optical flow algorithms are generally categorised into descriptor-based matching and pixel-based matching.Descriptor-based approaches are robust to geometric variation,however they have inherent loc...Large displacement optical flow algorithms are generally categorised into descriptor-based matching and pixel-based matching.Descriptor-based approaches are robust to geometric variation,however they have inherent localisation precision limitation due to histogram nature.This work presents a novel method called improved precision dense descriptor flow(IPDDF).The authors introduce an additional pixel-based matching cost within an existing dense Daisy descriptor framework to improve the flow estimation precision.Pixel-based features such as pixel colour and gradient are computed on top of the original descriptor in the authors’matching cost formulation.The pixel-based cost only requires a light-weight pre-computation and can be adapted seamlessly into the matching cost formulation.The framework is built based on the Daisy Filter Flow work.In the framework,Daisy descriptor and a filter-based efficient flow inference technique,as well as a randomised fast patch match search algorithm,are adopted.Given the novel matching cost formulation,the framework enables efficiently solving dense correspondence field estimation in a high-dimensional search space,which includes scale and orientation.Experiments on various challenging image pairs demonstrate the proposed algorithm enhances flow estimation accuracy as well as generate a spatially coherent yet edge-aware flow field result efficiently.展开更多
The aim of the study was to investigate the effect of pre-treatments by using sodium hydroxide (NaOH) and acetic acid on oil palm Empty Fruit Bunch (EFB) fibres for the production of Medium Density Fibreboard (MDF). T...The aim of the study was to investigate the effect of pre-treatments by using sodium hydroxide (NaOH) and acetic acid on oil palm Empty Fruit Bunch (EFB) fibres for the production of Medium Density Fibreboard (MDF). The EFB fibres were treated with chemicals in the concentration range of 0.2%, 0.4%, 0.6% and 0.8% prior to refining. Single-homogenous layer MDF with 12 mm thickness and density of 720 kg/m3 was produced. Urea-Formaldehyde (UF) was applied at 10% loading (based on dry weight of dry fibres) as a binder. The physical properties (Water Absorption (WA) and Thickness Swelling (TS)) of the produced panels were tested according to European Standard, EN 622-5:2006. The results show that types of chemical used had greater effects than concentration on the dimensional stability of the MDF. EFB fibres treated with acetic acid produced MDF with better dimensional stability compared to the MDF NaOH treated fibres. High concentration of NaOH produced poor dimensional stability in the panels.展开更多
The pressure broadening in the far wings,where the sodium Na(3 p←3 s)resonance line is perturbed by ground lithium Li(2 s)atoms,has been theoretically analyzed.The NaLi potential–energy curves and the transition dip...The pressure broadening in the far wings,where the sodium Na(3 p←3 s)resonance line is perturbed by ground lithium Li(2 s)atoms,has been theoretically analyzed.The NaLi potential–energy curves and the transition dipole moments are constructed by using a reliable ab initio data points to carry out the reduced-absorption coefficients k_(r)(ν,T).This quantum-mechanical investigation have demonstrated that the NaLi profile spectra show a satellite future in the red wing at wavelengthλ=685 nm in the temperature range 4000 K–1.8×10^(4) K.The computation could also exhibit a second satellite,in the blue wing,near the wavelengthλ=574 nm beyond 6000 K and a third peak located atλ=490 nm which begins to appear at 1.8×10^(-4) K.展开更多
We consider, for a bounded open domain Ω in R<sup>n</sup> and a function u : Ω → R<sup>m</sup>, the quasilinear elliptic system: <img src="Edit_8a3d3105-dccb-405b-bbbc-2084b80b6def.b...We consider, for a bounded open domain Ω in R<sup>n</sup> and a function u : Ω → R<sup>m</sup>, the quasilinear elliptic system: <img src="Edit_8a3d3105-dccb-405b-bbbc-2084b80b6def.bmp" alt="" /> (1). We generalize the system (QES)<sub>(f,g)</sub> in considering a right hand side depending on the jacobian matrix Du. Here, the star in (QES)<sub>(f,g)</sub> indicates that f may depend on Du. In the right hand side, v belongs to the dual space W<sup>-1,P’</sup>(Ω, <span style="white-space:nowrap;">ω<sup>*</sup>, R<sup>m</sup>), <img src="Edit_d584a286-6ceb-420c-b91f-d67f3d06d289.bmp" alt="" />, f and g satisfy some standard continuity and growth conditions. We prove existence of a regularity, growth and coercivity conditions for σ, but with only very mild monotonicity assumptions.展开更多
A human's e-life needs multiple offline and online accounts. It is a balance between usability and security to set keys or passwords for these multiple accounts. Password reuse has to be avoided due to the domino ...A human's e-life needs multiple offline and online accounts. It is a balance between usability and security to set keys or passwords for these multiple accounts. Password reuse has to be avoided due to the domino effect of malicious administrators and crackers. However,human memorability constrains the number of keys. Single sign-on server,key hashing,key strengthening and petname system are used in the prior arts to use only one key for multiple online accounts. The unique site keys are derived from the common master secret and specific domain name. These methods cannot be applied to offline accounts such as file encryption. We invent a new method and system applicable to offline and online accounts. It does not depend on HTTP server and domain name,but numeric 4-digit passcode,key hashing,key strengthening and hash truncation. Domain name is only needed to resist spoofing and phishing attacks of online accounts.展开更多
Successful development of broadband over powerline is obviously a potential solution for wired communication systems with the existence of the powerline network. From past research, it is known that the powerline chan...Successful development of broadband over powerline is obviously a potential solution for wired communication systems with the existence of the powerline network. From past research, it is known that the powerline channel suffers from multipath fading, frequency selectivity and also impulsive noise. Multi Carrier Code Division Multiple Access (MC-CDMA) is a promising solution for an impulsive noise powerline channel. This paper starts with the MC-CDMA transmitter structure and focuses on powerline channel model, noise model and various types of available channel estimators. The main concern in Powerline Communication Systems is the existence of impulsive noise. The proposed pilot assisted channel estimation uses the modified least square estimator that reduces the effect of impulsive noise in the estimated channel impulse response.展开更多
Background: Cancer is a leading cause of death worldwide as well as in Peru. The national cancer plan includes decentralization, but one of the greatest barriers is our complicated geography. San Martin is a departmen...Background: Cancer is a leading cause of death worldwide as well as in Peru. The national cancer plan includes decentralization, but one of the greatest barriers is our complicated geography. San Martin is a department located in the Peruvian jungle where there are no public services for cancer care. Our aim was to implement a “distance telemedicine-enabled” outpatient chemotherapy module, monitored by oncologists. Methods: The implementation was conducted in 3 stages: 1) Planning and Organization: working teams were formed, a chemotherapy room was developed and people were trained. 2) Execution: patients from San Martín region, aged >18 years with pathological confirmation of cancer, requiring systemic chemotherapy, ECOG <3, and first course of chemotherapy received at INEN without adverse reaction were selected. 3) Evaluation: adverse events, cost-user evaluation and quality of life (QoL) were assessed. Results: By November 2015, a module with a chemotherapy room with 18 chairs, a pharmacy, a hospitalization room, 1 medical office, a training room, a nutrition area, and a nursing station was implemented. 3 physicians, 3 nurses and 1 pharmacist were trained. Through March 2018, 501 sessions of teleoncology were completed to deliver 232 cycles of chemotherapy for 56 patients aged 19 - 78 years with different solid tumors, with no serious adverse event, without negatively affecting their QoL, and with an average out-of-pocket expense saving of 500 PEN. Conclusions: Using information and communication technology, a telechemotherapy module was successfully implemented in the Peruvian jungle, without adversely affecting the QoL of patients. Neither patients nor family members needed to travel to Lima to receive chemotherapy. This first program can be replicated in other rural and remote regions through non-specialized personnel and facilities, providing chemotherapy services equivalent to a tertiary center through trained health care professionals, supported through telemedicine.展开更多
We study the Dirichlet problem associated to strongly nonlinear parabolic equations involving p（x） structure in W;L;（Q）. We prove the existence of weak solutions by applying Galerkin’s approximation method.
基金support from the Ministry of Higher Education Malaysia under grant HICOE-2023-005.
文摘A unitized regenerative fuel cell(URFC)is a device that may function reversibly as either a fuel cell(FC)or water elec-trolysis(WE).An important component of this device is the Membrane electrode assembly(MEA).Therefore,this study aimed to compare the performance outcomes of MEA using electrodes with single and three catalyst layers.This study measured Electrochemical Surface Area(ECSA),Electrochemical Impedance Spectroscopy(EIS),X-ray Diffraction analysis(XRD),and X-ray Fluorescence(XRF).Furthermore,the round-trip efficiency(RTE)of the MEA,as w ell as the performance in FC and WE mode,was measured.In comparison,The ECSA values of Pt-Ru/C and Pt/C with three catalyst layers were higher than the single catalyst layer.This result was supported by electrode characterization data for XRD and XRF.The respective electrical conductivity values of Pt-Ru/C and Pt/C with three catalyst layers are also higher than the single cata-lyst layer,and the performance of URFC using MEA with three catalyst layers has the highest value of RTE among the MEA performances of URFC,which is 100%at a current density of 4 mA·cm-2.
基金supported by NSFC(No.11701339,11871206,11871479,12071484)Hunan Provincial Natural Science Foundation(No.2020JJ5096,2018JJ2479,2020JJ4675)Shandong Province Natural Science Foundation of(No.ZR2018MA012)
文摘A research has been carried out to investigate the mechanical properties of composites made by hybridizing sugar palm fibre （Arenga pinnata） with glass fibre into an unsaturated polyester matrix. Hybrid composites of glass/sugar palm fibre were fabricated in different weight ratios of strand mat glass fibres ： sugar palm fibres 4：0, 4：1, 4：2, 4：3, 4：4, and 0：4. The hybrid effects of glass and sugar palm fibre on tensile, flexural and impact properties of the composites were evaluated according to ASTM D5083, ASTM D790 and ASTM D256 respectively. Results have been established that properties of hybrid glass/sugar palm composites such as tensile strength, tensile modulus, elongation at break, toughness, flexural strength, flexural modulus and impact strength are a function of fibre content. The failure mechanism and the adhesion between fibres/matrix were studied by observing the scanning electron micrographs of impact fracture samples. In general, the incorporation of both fibres into unsaturated polyester matrix shows a regular trend of increase in the mechanical properties.
基金supported by funding from a Veterans Administration BLR&D merit review grant 1–101-BX-002717 to Dr Subburaman Mohan
文摘To evaluate the long-term consequence of repetitive mild traumatic brain injury （mTBI） on bone, mTBI was induced in 10-week-old female C57BL/6J mice using a weight drop model, once per day for 4 consecutive days at different drop heights （0.5, 1 and 1.5 m） and the skeletal phenotype was evaluated at different time points after the impact. In vivo micro-CT （μ-CT） analysis of the tibial metaphysis at 2, 8 and 12 weeks after the impact revealed a 5%-32% reduction in trabecular bone mass. Histomorphometric analyses showed a reduced bone formation rate in the secondary spongiosa ofl.5 m impacted mice at 12 weeks post impact. Apparent modulus （bone strength）, was reduced by 30% （P 〈 0.05） at the proximal tibial metaphysis in the 1.5 m drop height group at 2 and 8 weeks post impact. Ex vivo μ-CT analysis of the fifth lumbar vertebra revealed a significant reduction in trabecular bone mass at 12 weeks of age in all three drop height groups. Serum levels of osteocalcin were decreased by 22%, 15%, and 19% in the 0.5, 1.0 and 1.5 m drop height groups, respectively, at 2 weeks post impact. Serum IGF-I levels were reduced by 18%-32% in mTBI mice compared to control mice at 2 weeks post impact. Serum osteocalcin and IGF-I levels correlated with trabecular BV/TV （r2 = 0.14 and 0.16, P 〈 0.05）. In conclusion, repetitive mTBI exerts significant negative effects on the trabecular bone microarchitecture and bone mechanical properties by influencing osteoblast function via reduced endocrine IGF-I actions.
基金the National Natural Science Foundation of China(Grants No.11971486,11771452)the Natural Science Foundation of Hunan(Grants No.2019JJ40357,2020JJ4674)the Innovation Program of Central South University(Grants No.2020zzts036,2020zzts039)
文摘Analytical solutions of temperature distributions and the Nusselt numbers in forced convection are reported for flow through infinitely long parallel plates, where the upper plate moves in the flow direction with constant velocity and the lower plate is kept stationary. The flow is assumed to be laminar, both hydro-dynamically and thermally fully developed, taking into account the effect of viscous dissipation of the flowing fluid. Both the plates being kept at specified and at different constant heat fluxes are considered as thermal boundary conditions. The solutions obtained from energy equation are in terms of Brinkman number, dimensionless velocity and heat flux ratio. These parameters greatly influence and give complete understanding on heat transfer rates that has potentials for designing and analyzing energy equipment and processes.
文摘Large displacement optical flow algorithms are generally categorised into descriptor-based matching and pixel-based matching.Descriptor-based approaches are robust to geometric variation,however they have inherent localisation precision limitation due to histogram nature.This work presents a novel method called improved precision dense descriptor flow(IPDDF).The authors introduce an additional pixel-based matching cost within an existing dense Daisy descriptor framework to improve the flow estimation precision.Pixel-based features such as pixel colour and gradient are computed on top of the original descriptor in the authors’matching cost formulation.The pixel-based cost only requires a light-weight pre-computation and can be adapted seamlessly into the matching cost formulation.The framework is built based on the Daisy Filter Flow work.In the framework,Daisy descriptor and a filter-based efficient flow inference technique,as well as a randomised fast patch match search algorithm,are adopted.Given the novel matching cost formulation,the framework enables efficiently solving dense correspondence field estimation in a high-dimensional search space,which includes scale and orientation.Experiments on various challenging image pairs demonstrate the proposed algorithm enhances flow estimation accuracy as well as generate a spatially coherent yet edge-aware flow field result efficiently.
文摘The aim of the study was to investigate the effect of pre-treatments by using sodium hydroxide (NaOH) and acetic acid on oil palm Empty Fruit Bunch (EFB) fibres for the production of Medium Density Fibreboard (MDF). The EFB fibres were treated with chemicals in the concentration range of 0.2%, 0.4%, 0.6% and 0.8% prior to refining. Single-homogenous layer MDF with 12 mm thickness and density of 720 kg/m3 was produced. Urea-Formaldehyde (UF) was applied at 10% loading (based on dry weight of dry fibres) as a binder. The physical properties (Water Absorption (WA) and Thickness Swelling (TS)) of the produced panels were tested according to European Standard, EN 622-5:2006. The results show that types of chemical used had greater effects than concentration on the dimensional stability of the MDF. EFB fibres treated with acetic acid produced MDF with better dimensional stability compared to the MDF NaOH treated fibres. High concentration of NaOH produced poor dimensional stability in the panels.
文摘The pressure broadening in the far wings,where the sodium Na(3 p←3 s)resonance line is perturbed by ground lithium Li(2 s)atoms,has been theoretically analyzed.The NaLi potential–energy curves and the transition dipole moments are constructed by using a reliable ab initio data points to carry out the reduced-absorption coefficients k_(r)(ν,T).This quantum-mechanical investigation have demonstrated that the NaLi profile spectra show a satellite future in the red wing at wavelengthλ=685 nm in the temperature range 4000 K–1.8×10^(4) K.The computation could also exhibit a second satellite,in the blue wing,near the wavelengthλ=574 nm beyond 6000 K and a third peak located atλ=490 nm which begins to appear at 1.8×10^(-4) K.
文摘We consider, for a bounded open domain Ω in R<sup>n</sup> and a function u : Ω → R<sup>m</sup>, the quasilinear elliptic system: <img src="Edit_8a3d3105-dccb-405b-bbbc-2084b80b6def.bmp" alt="" /> (1). We generalize the system (QES)<sub>(f,g)</sub> in considering a right hand side depending on the jacobian matrix Du. Here, the star in (QES)<sub>(f,g)</sub> indicates that f may depend on Du. In the right hand side, v belongs to the dual space W<sup>-1,P’</sup>(Ω, <span style="white-space:nowrap;">ω<sup>*</sup>, R<sup>m</sup>), <img src="Edit_d584a286-6ceb-420c-b91f-d67f3d06d289.bmp" alt="" />, f and g satisfy some standard continuity and growth conditions. We prove existence of a regularity, growth and coercivity conditions for σ, but with only very mild monotonicity assumptions.
文摘A human's e-life needs multiple offline and online accounts. It is a balance between usability and security to set keys or passwords for these multiple accounts. Password reuse has to be avoided due to the domino effect of malicious administrators and crackers. However,human memorability constrains the number of keys. Single sign-on server,key hashing,key strengthening and petname system are used in the prior arts to use only one key for multiple online accounts. The unique site keys are derived from the common master secret and specific domain name. These methods cannot be applied to offline accounts such as file encryption. We invent a new method and system applicable to offline and online accounts. It does not depend on HTTP server and domain name,but numeric 4-digit passcode,key hashing,key strengthening and hash truncation. Domain name is only needed to resist spoofing and phishing attacks of online accounts.
文摘Successful development of broadband over powerline is obviously a potential solution for wired communication systems with the existence of the powerline network. From past research, it is known that the powerline channel suffers from multipath fading, frequency selectivity and also impulsive noise. Multi Carrier Code Division Multiple Access (MC-CDMA) is a promising solution for an impulsive noise powerline channel. This paper starts with the MC-CDMA transmitter structure and focuses on powerline channel model, noise model and various types of available channel estimators. The main concern in Powerline Communication Systems is the existence of impulsive noise. The proposed pilot assisted channel estimation uses the modified least square estimator that reduces the effect of impulsive noise in the estimated channel impulse response.
文摘Background: Cancer is a leading cause of death worldwide as well as in Peru. The national cancer plan includes decentralization, but one of the greatest barriers is our complicated geography. San Martin is a department located in the Peruvian jungle where there are no public services for cancer care. Our aim was to implement a “distance telemedicine-enabled” outpatient chemotherapy module, monitored by oncologists. Methods: The implementation was conducted in 3 stages: 1) Planning and Organization: working teams were formed, a chemotherapy room was developed and people were trained. 2) Execution: patients from San Martín region, aged >18 years with pathological confirmation of cancer, requiring systemic chemotherapy, ECOG <3, and first course of chemotherapy received at INEN without adverse reaction were selected. 3) Evaluation: adverse events, cost-user evaluation and quality of life (QoL) were assessed. Results: By November 2015, a module with a chemotherapy room with 18 chairs, a pharmacy, a hospitalization room, 1 medical office, a training room, a nutrition area, and a nursing station was implemented. 3 physicians, 3 nurses and 1 pharmacist were trained. Through March 2018, 501 sessions of teleoncology were completed to deliver 232 cycles of chemotherapy for 56 patients aged 19 - 78 years with different solid tumors, with no serious adverse event, without negatively affecting their QoL, and with an average out-of-pocket expense saving of 500 PEN. Conclusions: Using information and communication technology, a telechemotherapy module was successfully implemented in the Peruvian jungle, without adversely affecting the QoL of patients. Neither patients nor family members needed to travel to Lima to receive chemotherapy. This first program can be replicated in other rural and remote regions through non-specialized personnel and facilities, providing chemotherapy services equivalent to a tertiary center through trained health care professionals, supported through telemedicine.
文摘We study the Dirichlet problem associated to strongly nonlinear parabolic equations involving p（x） structure in W;L;（Q）. We prove the existence of weak solutions by applying Galerkin’s approximation method.
