With integrated equipment health prognosis, both physical models and condition monitoring data are utilized to achieve more accurate prediction of equipment remaining useful life (RUL). In this paper, an integrated ...With integrated equipment health prognosis, both physical models and condition monitoring data are utilized to achieve more accurate prediction of equipment remaining useful life (RUL). In this paper, an integrated prognostics method is proposed to account for two important factors which were not considered before, the uncertainty in crack initiation time (CIT) and the shock in the degradation. Prognostics tools are used for RUL pre- diction starting from the CIT. However, there is uncertainty in CIT due to the limited capability of existing fault detection tools, and such uncertainty has not been explic- itly considered in the literature for integrated prognosis. A shock causes a sudden damage increase and creates a jump in the degradation path, which shortens the total lifetime, and it has not been considered before in the integrated prognostics framework either. In the proposed integrated prognostics method, CIT is considered as an uncertain parameter, which is updated using condition monitoring data. To deal with the sudden damage increase and reduction of total lifetime, a virtual gradual degradation path with an earlier CIT is introduced in the proposed method. In this way, the effect of shock is captured through identifying an appropriate CIT. Examples of gear prog- nostics are given to demonstrate the effectiveness of the proposed method.展开更多
The correlation between the initial time value of transient iterative parameters and the blowing pressure in the numerical simulation process of blowing balloon is investigated by POLYFLOW. The results show that: 1) A...The correlation between the initial time value of transient iterative parameters and the blowing pressure in the numerical simulation process of blowing balloon is investigated by POLYFLOW. The results show that: 1) As the blow molding pressure increases, the boundary value of the iterative time step decreases rapidly at first and then slowly. At the end of the first step of iterative calculation for each boundary value, the balloon parison is in the mold core cavity. 2) If the initial time value of transient iterative parameters is smaller than the boundary value of the iterative time step, the balloon parison is still in the mold core cavity at the end of the first iteration. However, if the iterative calculation continues, the calculation process may be interrupted when the time step is smaller than the initial time value of the transient iterative parameters, which makes the blow molding simulation of balloon unable to continue. 3) It is suggested that the initial time value of transient iterative parameters is one order of magnitude smaller than the boundary value of the iterative time step to complete smoothly the simulation of blow molding balloon.展开更多
Previous studies have shown that there are some ca.770–750 Ma mafic dykes at the western segment of the Neoproterozoic Jiangnan orogen(JO),and they represent post-orogenic magmatism due to orogenic collapse(Wang
A result from Kieffer, as outlined at the beginning of the article identifies two different candidates for initial time steps, delta t. We assert that this difference in time steps may be related to a specific early u...A result from Kieffer, as outlined at the beginning of the article identifies two different candidates for initial time steps, delta t. We assert that this difference in time steps may be related to a specific early universe Lorentz Violation. The author asserts that the existence of early universe Lorentz violation in turn is assisting in a breakup of primordial black holes. And that also has a tie into Kieffer different time steps as outlined. And the wrap up is given in the final part of this document.展开更多
This article poses the question of a minimum cosmological constant, i.e. vacuum energy at the start of the cosmological evolution from a near singularity. We pose this comparing formalism as given by Berry (1976) as t...This article poses the question of a minimum cosmological constant, i.e. vacuum energy at the start of the cosmological evolution from a near singularity. We pose this comparing formalism as given by Berry (1976) as to a small time length, and compare that in its entirety to compare this value given by Berry (1976) with a minimum time length at the start of cosmological space-time evolution. Using the methodology of Zeldovich (1972) as to a problem with electron-positron pair production we also propose another upper bound to the problem of minimum time length which may be accessible to experimental inquiry. This then makes the problem of minimum time length a way of specifying a magnetic field dependence of the cosmological constant, which has major implications to answering if quintessence, i.e. a changing cosmological vacuum energy, or a constant for the “cosmological constant” problem. Our answer is an initial value for the cosmological vacuum energy 10<sup>10</sup> - 10<sup>20</sup> times greater than today which suggests either Quintessence, or if still a constant, a much better value for this parameter than what is suggested by traditional field theory methods. In closing we review how our construct supports work done by Corda, as to early universe models and what the implications are, as to the choices we have made.展开更多
A laboratory study was undertaken to investigate drying shrinkage and cracking sensitivity subjected to restrained shrinkage of mortar containing fly ash (FA), granulated blast-furnace slag (GBFS) and silica fume (SF)...A laboratory study was undertaken to investigate drying shrinkage and cracking sensitivity subjected to restrained shrinkage of mortar containing fly ash (FA), granulated blast-furnace slag (GBFS) and silica fume (SF). Six mortar mixtures including control Portland cement (PC) and FA, GBFS and SF mortar mixtures were prepared. FA replaced the cement on mass basis at the replacement ratios of 20% and 35%, GBFS replaced the cement at the replacement ratios of 40%, SF replaced the cement at the replacement ratios of 8% and the blended mixtures with 20% FA, 20% GBFS and 8% SF. Water-cementitious materials ratio and sand-cementitious materials ratio were 0.4 and 2.0 for all mixtures, respectively. The mixtures were cured at 65% relative humidity and 20℃. The drying shrinkage value, initial cracking time and cracking width of the mortar samples were measured. The results show that all the mortar mixture containing FA exhibited the decrease of drying shrinkage. Moreover, initial cracking time was markedly delayed, and the crack width of the initial crack was reduced. However, the incorporations of various ratios of GBFS and SF led to an increase of drying shrinkage, initial cracking time and cracking width as compared to control mixture.展开更多
The primary objective of this research was to determine optimum dosage of mixing concrete containing plasticizers and fly ash, consistent with desirable structural grade concrete properties. Factorial tests were also ...The primary objective of this research was to determine optimum dosage of mixing concrete containing plasticizers and fly ash, consistent with desirable structural grade concrete properties. Factorial tests were also conducted to investigate the four main factors: water-cementing materials ratio, water content, content of superplasticizers (SP) and fly ash content. It was found that the requirement for setting time played the dominant role in shrinkage and anti-cracking, and fly ash played a critical role in workability and reducing heat of hydration but showed insignificant effects on slump, early strength and initial setting time of concrete.展开更多
In this paper,a new method to calculate collision risk of air-routes,based on variable nominal separation,is proposed. The collision risk model of air-routes,based on the time variable and initial time interval variab...In this paper,a new method to calculate collision risk of air-routes,based on variable nominal separation,is proposed. The collision risk model of air-routes,based on the time variable and initial time interval variable,is given. Because the distance and the collision probability vary with time when the nominal relative speed between aircraft is not zero for a fixed initial time interval,the distance,the variable nominal separation,and the collision probability at any time can be expressed as functions of time and initial time interval. By the probabilistic theory,a model for calculating collision risk is acquired based on initial time interval distribution,flow rates,and the proportion of aircraft type. From the results of calculations,the collision risk can be characterized by the model when the nominal separation changes with time. As well the roles of parameters can be shown more readily.展开更多
Acute kidney injury remains a serious condition with a high mortality risk. In the absence of any new drugs, renal replacement therapy (RRT) is the most important treatment option. Randomized controlled trials have co...Acute kidney injury remains a serious condition with a high mortality risk. In the absence of any new drugs, renal replacement therapy (RRT) is the most important treatment option. Randomized controlled trials have concluded that in critically ill patients without an emergency indication for RRT, a watchful waiting strategy is safe;however, further delays in RRT did not seem to confer any benefit, rather was associated with potential harm. During this process, balancing the risks of complications due to an unnecessary intervention with the risk of not correcting a potentially life-threatening complication remains a challenge. Dynamic renal function assessment, especially dynamic assessment of renal demand-capacity matching, combined with renal biomarkers such as neutrophil gelatinase-associated lipocalin and furosemide stress test, is helpful to identify which patients and when the patients may benefit from RRT.展开更多
Referring to a set of real time tasks with arriving time,executing time and deadline,this paperdiscusses the problem of polynomial time initial-allocating approximation algorithms in a distributedsystem and five new r...Referring to a set of real time tasks with arriving time,executing time and deadline,this paperdiscusses the problem of polynomial time initial-allocating approximation algorithms in a distributedsystem and five new results are gained which provide a theory for the designing of initial-allocating algorithmsof real time tasks.展开更多
A novel cathodic–anodic-electrolysis packing(CAEP) used in the treatment of pyridine wastewater was researched, which mainly consisted of 4,4′-diamino-2,2′-disulfonic acid(DSD acid) industrial iron sludge. The ...A novel cathodic–anodic-electrolysis packing(CAEP) used in the treatment of pyridine wastewater was researched, which mainly consisted of 4,4′-diamino-2,2′-disulfonic acid(DSD acid) industrial iron sludge. The physical properties and morphology of the packing were studied. The CAEP was used in a column reactor during the pretreatment of pyridine wastewater. The influence of p H, hydraulic retention time(HRT), the air–liquid ratio(A/L)and the initial concentration of pyridine were investigated by measuring the removal of total organic carbon(TOC) and pyridine. The characterization results showed that the bulk density, grain density, water absorption percentage and specific surface area were 921 kg/m3,1086 kg/m3, 25% and 29.89 m^2/g, respectively; the removal of TOC and pyridine could reach50% and 58% at the optimal experimental conditions(p H = 3, HRT = 8 hr, A/L = 2). Notably,the surface of the packing was renewed constantly during the running of the filter, and the handling capacity was stable after running for three months.展开更多
Objective:To examine referral pattern,the timing of diagnostic/staging processes,and treatment initiation for new head and neck cancer patients in a community setting.Methods:Patients with a newly diagnosed previously...Objective:To examine referral pattern,the timing of diagnostic/staging processes,and treatment initiation for new head and neck cancer patients in a community setting.Methods:Patients with a newly diagnosed previously untreated diagnosis of head neck cancer managed at Asplundh Cancer Pavilion/Abington Memorial Hospital from October 2018 to March 2020.Source of referral and preceding workup were examined as well as intervals between initial head and neck consult and various timepoints of treatment initiation.Results:One hundred and five patients were included in the study.The primary referral sources were external general otolaryngology(56.3%).Oral surgery and dermatology obtained tissue biopsy approximately 80%of the time before referral.The average time from the ordering of initial staging positron emission tomography/computed tomography to finalized results was 14 days(range:10-25 days).Patients referred from dermatology and oral surgery were more likely to require single modality care,namely definitive surgical management.Time to treatment initiation average was 37 days(range:29-41 days).Patients with longer treatment times noted significantly higher times to both radiation and medical oncology consults(48.42 vs.18.13 days;P<0.001).Conclusions:No notable differences in treatment initiation times were identified based on referral source or extent of workup performed before head/neck surgery consult.It appears the largest opportunities for improvement in terms of reducing overall treatment length exist in the optimization of radiation initiation time.展开更多
基金Supported by Natural Sciences and Engineering Research Council of Canada(NSERC)
文摘With integrated equipment health prognosis, both physical models and condition monitoring data are utilized to achieve more accurate prediction of equipment remaining useful life (RUL). In this paper, an integrated prognostics method is proposed to account for two important factors which were not considered before, the uncertainty in crack initiation time (CIT) and the shock in the degradation. Prognostics tools are used for RUL pre- diction starting from the CIT. However, there is uncertainty in CIT due to the limited capability of existing fault detection tools, and such uncertainty has not been explic- itly considered in the literature for integrated prognosis. A shock causes a sudden damage increase and creates a jump in the degradation path, which shortens the total lifetime, and it has not been considered before in the integrated prognostics framework either. In the proposed integrated prognostics method, CIT is considered as an uncertain parameter, which is updated using condition monitoring data. To deal with the sudden damage increase and reduction of total lifetime, a virtual gradual degradation path with an earlier CIT is introduced in the proposed method. In this way, the effect of shock is captured through identifying an appropriate CIT. Examples of gear prog- nostics are given to demonstrate the effectiveness of the proposed method.
文摘The correlation between the initial time value of transient iterative parameters and the blowing pressure in the numerical simulation process of blowing balloon is investigated by POLYFLOW. The results show that: 1) As the blow molding pressure increases, the boundary value of the iterative time step decreases rapidly at first and then slowly. At the end of the first step of iterative calculation for each boundary value, the balloon parison is in the mold core cavity. 2) If the initial time value of transient iterative parameters is smaller than the boundary value of the iterative time step, the balloon parison is still in the mold core cavity at the end of the first iteration. However, if the iterative calculation continues, the calculation process may be interrupted when the time step is smaller than the initial time value of the transient iterative parameters, which makes the blow molding simulation of balloon unable to continue. 3) It is suggested that the initial time value of transient iterative parameters is one order of magnitude smaller than the boundary value of the iterative time step to complete smoothly the simulation of blow molding balloon.
文摘Previous studies have shown that there are some ca.770–750 Ma mafic dykes at the western segment of the Neoproterozoic Jiangnan orogen(JO),and they represent post-orogenic magmatism due to orogenic collapse(Wang
文摘A result from Kieffer, as outlined at the beginning of the article identifies two different candidates for initial time steps, delta t. We assert that this difference in time steps may be related to a specific early universe Lorentz Violation. The author asserts that the existence of early universe Lorentz violation in turn is assisting in a breakup of primordial black holes. And that also has a tie into Kieffer different time steps as outlined. And the wrap up is given in the final part of this document.
文摘This article poses the question of a minimum cosmological constant, i.e. vacuum energy at the start of the cosmological evolution from a near singularity. We pose this comparing formalism as given by Berry (1976) as to a small time length, and compare that in its entirety to compare this value given by Berry (1976) with a minimum time length at the start of cosmological space-time evolution. Using the methodology of Zeldovich (1972) as to a problem with electron-positron pair production we also propose another upper bound to the problem of minimum time length which may be accessible to experimental inquiry. This then makes the problem of minimum time length a way of specifying a magnetic field dependence of the cosmological constant, which has major implications to answering if quintessence, i.e. a changing cosmological vacuum energy, or a constant for the “cosmological constant” problem. Our answer is an initial value for the cosmological vacuum energy 10<sup>10</sup> - 10<sup>20</sup> times greater than today which suggests either Quintessence, or if still a constant, a much better value for this parameter than what is suggested by traditional field theory methods. In closing we review how our construct supports work done by Corda, as to early universe models and what the implications are, as to the choices we have made.
基金Funded by the 863 Program from Ministry of Science and Technology of China(2005AA332010) the Key Technologies R&D Program from Department of Science and Technology. Hubei Province (200410G0121)
文摘A laboratory study was undertaken to investigate drying shrinkage and cracking sensitivity subjected to restrained shrinkage of mortar containing fly ash (FA), granulated blast-furnace slag (GBFS) and silica fume (SF). Six mortar mixtures including control Portland cement (PC) and FA, GBFS and SF mortar mixtures were prepared. FA replaced the cement on mass basis at the replacement ratios of 20% and 35%, GBFS replaced the cement at the replacement ratios of 40%, SF replaced the cement at the replacement ratios of 8% and the blended mixtures with 20% FA, 20% GBFS and 8% SF. Water-cementitious materials ratio and sand-cementitious materials ratio were 0.4 and 2.0 for all mixtures, respectively. The mixtures were cured at 65% relative humidity and 20℃. The drying shrinkage value, initial cracking time and cracking width of the mortar samples were measured. The results show that all the mortar mixture containing FA exhibited the decrease of drying shrinkage. Moreover, initial cracking time was markedly delayed, and the crack width of the initial crack was reduced. However, the incorporations of various ratios of GBFS and SF led to an increase of drying shrinkage, initial cracking time and cracking width as compared to control mixture.
基金Funded by the National Natural Science Foundation of China(51409202)the Fundamental Research Funds for the Central Universities(2013-IV-36)the Jiangxi Provincial Project of Science and Technology(20132GGB70107)
文摘The primary objective of this research was to determine optimum dosage of mixing concrete containing plasticizers and fly ash, consistent with desirable structural grade concrete properties. Factorial tests were also conducted to investigate the four main factors: water-cementing materials ratio, water content, content of superplasticizers (SP) and fly ash content. It was found that the requirement for setting time played the dominant role in shrinkage and anti-cracking, and fly ash played a critical role in workability and reducing heat of hydration but showed insignificant effects on slump, early strength and initial setting time of concrete.
基金The National Natural Science Foundations(Nos. 60776813 and 60979018)the National Air Traffic Management Research Program ( GKG200802015)the NUAA Research Funding (NS2010184)
文摘In this paper,a new method to calculate collision risk of air-routes,based on variable nominal separation,is proposed. The collision risk model of air-routes,based on the time variable and initial time interval variable,is given. Because the distance and the collision probability vary with time when the nominal relative speed between aircraft is not zero for a fixed initial time interval,the distance,the variable nominal separation,and the collision probability at any time can be expressed as functions of time and initial time interval. By the probabilistic theory,a model for calculating collision risk is acquired based on initial time interval distribution,flow rates,and the proportion of aircraft type. From the results of calculations,the collision risk can be characterized by the model when the nominal separation changes with time. As well the roles of parameters can be shown more readily.
文摘Acute kidney injury remains a serious condition with a high mortality risk. In the absence of any new drugs, renal replacement therapy (RRT) is the most important treatment option. Randomized controlled trials have concluded that in critically ill patients without an emergency indication for RRT, a watchful waiting strategy is safe;however, further delays in RRT did not seem to confer any benefit, rather was associated with potential harm. During this process, balancing the risks of complications due to an unnecessary intervention with the risk of not correcting a potentially life-threatening complication remains a challenge. Dynamic renal function assessment, especially dynamic assessment of renal demand-capacity matching, combined with renal biomarkers such as neutrophil gelatinase-associated lipocalin and furosemide stress test, is helpful to identify which patients and when the patients may benefit from RRT.
文摘Referring to a set of real time tasks with arriving time,executing time and deadline,this paperdiscusses the problem of polynomial time initial-allocating approximation algorithms in a distributedsystem and five new results are gained which provide a theory for the designing of initial-allocating algorithmsof real time tasks.
基金supported by the Tai Shan Scholar Foundation(No.ts201511003)
文摘A novel cathodic–anodic-electrolysis packing(CAEP) used in the treatment of pyridine wastewater was researched, which mainly consisted of 4,4′-diamino-2,2′-disulfonic acid(DSD acid) industrial iron sludge. The physical properties and morphology of the packing were studied. The CAEP was used in a column reactor during the pretreatment of pyridine wastewater. The influence of p H, hydraulic retention time(HRT), the air–liquid ratio(A/L)and the initial concentration of pyridine were investigated by measuring the removal of total organic carbon(TOC) and pyridine. The characterization results showed that the bulk density, grain density, water absorption percentage and specific surface area were 921 kg/m3,1086 kg/m3, 25% and 29.89 m^2/g, respectively; the removal of TOC and pyridine could reach50% and 58% at the optimal experimental conditions(p H = 3, HRT = 8 hr, A/L = 2). Notably,the surface of the packing was renewed constantly during the running of the filter, and the handling capacity was stable after running for three months.
文摘Objective:To examine referral pattern,the timing of diagnostic/staging processes,and treatment initiation for new head and neck cancer patients in a community setting.Methods:Patients with a newly diagnosed previously untreated diagnosis of head neck cancer managed at Asplundh Cancer Pavilion/Abington Memorial Hospital from October 2018 to March 2020.Source of referral and preceding workup were examined as well as intervals between initial head and neck consult and various timepoints of treatment initiation.Results:One hundred and five patients were included in the study.The primary referral sources were external general otolaryngology(56.3%).Oral surgery and dermatology obtained tissue biopsy approximately 80%of the time before referral.The average time from the ordering of initial staging positron emission tomography/computed tomography to finalized results was 14 days(range:10-25 days).Patients referred from dermatology and oral surgery were more likely to require single modality care,namely definitive surgical management.Time to treatment initiation average was 37 days(range:29-41 days).Patients with longer treatment times noted significantly higher times to both radiation and medical oncology consults(48.42 vs.18.13 days;P<0.001).Conclusions:No notable differences in treatment initiation times were identified based on referral source or extent of workup performed before head/neck surgery consult.It appears the largest opportunities for improvement in terms of reducing overall treatment length exist in the optimization of radiation initiation time.