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RESUME CONTEXTE: Les caracteristiques des patients, les soins cliniques, l’utilisation des ressources et les issues cliniques des personnes atteintes de la maladie a coronavirus 2019 (COVID-19) hospitalisees au Canada ne sont pas bien connus. METHODES: Nous avons recueilli des donnees sur tous les adultes hospitalises atteints de la COVID-19 ou de l’influenza ayant obtenu leur conge d’unites medicales ou d’unites de soins intensifs medicaux et chirurgicaux entre le 1er novembre 2019 et le 30 juin 2020 dans 7 centres hospitaliers de Toronto et de Mississauga (Ontario). Nous avons compare les issues cliniques des patients a l’aide de modeles de regression multivariee, en tenant compte des facteurs sociodemographiques et de l’intensite des comorbidites. Nous avons valide le degre d’exactitude de 7 scores de risque mis au point a l’externe pour determiner leur capacite a predire le risque de deces chez les patients atteints de la COVID-19. RESULTATS: Parmi les hospitalisations retenues, 1027 patients etaient atteints de la COVID-19 (âge median de 65 ans, 59,1 % d’hommes) et 783 etaient atteints de l’influenza (âge median de 68 ans, 50,8 % d’hommes). Les patients âges de moins de 50 ans comptaient pour 21,2 % de toutes les hospitalisations dues a la COVID-19 et 24,0 % des sejours aux soins intensifs. Comparativement aux patients atteints de l’influenza, les patients atteints de la COVID-19 presentaient un taux de mortalite perhospitaliere (mortalite non ajustee 19,9 % c. 6,1 %; risque relatif [RR] ajuste 3,46 %, intervalle de confiance [IC] a 95 % 2,56–4,68) et un taux d’utilisation des ressources des unites de soins intensifs (taux non ajuste 26,4 % c. 18,0 %; RR ajuste 1,50, IC a 95 % 1,25–1,80) significativement plus eleves, ainsi qu’une duree d’hospitalisation (duree mediane non ajustee 8,7 jours c. 4,8 jours; rapport des taux d’incidence ajuste 1,45; IC a 95 % 1,25–1,69) significativement plus longue. Le taux de rehospitalisation dans les 30 jours n’etait pas significativement different (taux non ajuste 9,3 % c. 9,6 %; RR ajuste 0,98 %, IC a 95 % 0,70–1,39). Trois scores de risque utilisant un pointage pour predire la mortalite perhospitaliere ont montre une bonne discrimination (aire sous la courbe [ASC] de la fonction d’efficacite du recepteur [ROC] 0,72–0,81) et une bonne calibration. INTERPRETATION: Durant la premiere vague de la pandemie, l’hospitalisation des patients atteints de la COVID-19 etait associee a des taux de mortalite et d’utilisation des ressources des unites de soins intensifs et a une duree d’hospitalisation significativement plus importants que les hospitalisations des patients atteints de l’influenza. De simples scores de risque peuvent predire avec une bonne exactitude le risque de mortalite perhospitaliere des patients atteints de la COVID-19.

BackgroundVariations in inpatient medical care are typically attributed to system, hospital or patient factors. Little is known about variations at the physician level within hospitals. We described the physician-level variation in clinical outcomes and resource use in general internal medicine (GIM).MethodsThis was an observational study of all emergency admissions to GIM at seven hospitals in Ontario, Canada, over a 5-year period between 2010 and 2015. Physician-level variations in inpatient mortality, hospital length of stay, 30-day readmission and use of ‘advanced imaging’ (CT, MRI or ultrasound scans) were measured. Physicians were categorised into quartiles within each hospital for each outcome and then quartiles were pooled across all hospitals (eg, physicians in the highest quartile at each hospital were grouped together). We report absolute differences between physicians in the highest and lowest quartiles after matching admissions based on propensity scores to account for patient-level variation.ResultsThe sample included 103 085 admissions to 135 attending physicians. After propensity score matching, the difference between physicians in the highest and lowest quartiles for in-hospital mortality was 2.4% (95% CI 0.6% to 4.3%, pConclusionsPatient outcomes and resource use in inpatient medical care varied substantially across physicians in this study. Physician-level variations in length of stay and imaging use were unlikely to be explained by patient factors whereas differences in mortality and readmission should be interpreted with caution and could be explained by unmeasured confounders. Physician-level variations may represent practice differences that highlight quality improvement opportunities.

Background: Acute inpatient hospital admissions account for more than half of all health care costs related to diabetes. We sought to identify the most common and costly conditions leading to hospital admission among patients with diabetes compared with patients without diabetes. Methods: We used data from the General Internal Medicine Inpatient Initiative (GEMINI) study, a retrospective cohort study, of all patients admitted to a general internal medicine service at 7 Toronto hospitals between 2010 and 2015. The Canadian Institute for Health Information (CIHI) Most Responsible Diagnosis code was used to identify the 10 most frequent reasons for admission in patients with diabetes. Cost of hospital admission was estimated using the CIHI Resource Intensity Weight. Comparisons were made between patients with or without diabetes using the Pearson χ2 test for frequency and distribution-free confidence intervals (CIs) for median cost. Results: Among the 150 499 hospital admissions in our study, 41 934 (27.8%) involved patients with diabetes. Compared with patients without diabetes, hospital admissions because of soft tissue and bone infections were most frequent (2.5% v. 1.9%; prevalence ratio [PR] 1.28, 95% CI 1.19–1.37) and costly (Can$8794 v. Can$5845; cost ratio [CR] 1.50, 95% CI 1.37–1.65) among patients with diabetes. This was followed by urinary tract infections (PR 1.16, 95% CI 1.11–1.22; CR 1.23, 95% CI 1.17–1.29), stroke (PR 1.13, 95% CI 1.07–1.19; CR 1.19, 95% CI 1.14–1.25) and electrolyte disorders (PR 1.11, 95% CI 1.03–1.20; CR 1.20, 95% CI 1.08–1.34). Interpretation: Soft tissue and bone infections, urinary tract infections, stroke and electrolyte disorders are associated with a greater frequency and cost of hospital admissions in patients with diabetes than in those without diabetes. Preventive strategies focused on reducing hospital admissions secondary to these disorders may be beneficial in patients with diabetes.

BackgroundPatient characteristics, clinical care, resource use, and outcomes associated with hospitalization for coronavirus disease (COVID-19) in Canada are not well described.MethodsWe described all adult discharges from inpatient medical services and medical-surgical intensive care units (ICU) between November 1, 2019 and June 30, 2020 at 7 hospitals in Toronto and Mississauga, Ontario. We compared patients hospitalized with COVID-19, influenza and all other conditions using multivariable regression models controlling for patient age, sex, comorbidity, and residence in long-term-care.ResultsThere were 43,462 discharges in the study period, including 1,027 (3.0%) with COVID-19 and 783 (2.3%) with influenza. Patients with COVID-19 had similar age to patients with influenza and other conditions (median age 65 years vs. 68 years and 68 years, respectively, SDInterpretationAdults hospitalized with COVID-19 during the first wave of the pandemic used substantial hospital resources and suffered high mortality. COVID-19 was associated with significantly greater mortality, ICU use, and hospital length-of-stay than influenza.

Background The coronavirus disease 2019 (COVID-19) outbreak increases the importance of strategies to enhance urgent medical care delivery in long-term care (LTC) facilities that could potentially reduce transfers to emergency departments. The study objective was to model resource requirements to deliver virtual urgent medical care in LTC facilities. Methods We used data from all general medicine inpatient admissions at 7 hospitals in the Greater Toronto Area, Ontario, Canada, over a 7.5-year period (Apr. 1, 2010, to Oct. 31, 2017) to estimate historical patterns of hospital resource use by LTC residents. We estimated an upper bound of potentially avoidable transfers by combining data on short admissions (≤ 72 h) with historical data on the proportion of transfers from LTC facilities for which patients were discharged from the emergency department without admission. Regression models were used to extrapolate future resource requirements, and queuing models were used to estimate physician staffing requirements to perform virtual assessments. Results There were 235 375 admissions to general medicine wards, and residents of LTC facilities (age 16 yr or older) accounted for 9.3% (n = 21 948) of these admissions. Among the admissions of residents of LTC facilities, short admissions constituted 24.1% (n = 5297), and for 99.8% (n = 5284) of these admissions, the patient received laboratory testing, for 86.9% (n = 4604) the patient received plain radiography, for 41.5% (n = 2197) the patient received computed tomography and for 81.2% (n = 4300) the patient received intravenous medications. If all patients who have short admissions and are transferred from the emergency department were diverted to outpatient care, the average weekly demand for outpatient imaging per hospital would be 2.6 ultrasounds, 11.9 computed tomographic scans and 23.9 radiographs per week. The average daily volume of urgent medical virtual assessments would range from 2.0 to 5.8 per hospital. A single centralized virtual assessment centre staffed by 2 or 3 physicians would provide services similar in efficiency (measured by waiting time for physician assessment) to 7 separate centres staffed by 1 physician each. Interpretation The provision of acute medical care to LTC residents at their facility would probably require rapid access to outpatient diagnostic imaging, within-facility access to laboratory services and intravenous medication and virtual consultations with physicians. The results of this study can inform efforts to deliver urgent medical care in LTC facilities in light of a potential surge in COVID-19 cases.

In recent times, turbomolecular pumps (TMPs) have been used frequently to generate and maintain high and clean vacuum. Because of the high-speed rotation of the rotor, its structural safety should be treated as the first design concern. This paper presents the structural analysis and optimization of rotor blades of a TMP. To increase the numerical efficiency in the finite element modeling and analysis, the P-method provided in Pro/ENGINEER was used for simulation. The structural responses for several types of rotor blades were investigated, and the effects of the blade angle, blade length, and round size are thoroughly studied for each type of TMP blade. In addition, structural optimization to reduce and even the maximum stress at each stage of the TMP by changing the size of rounds between the blade and the hub was performed very successfully by using the P-method.

This study is aimed at representing efficient buckling analysis method by analyzing the buckling behavior and the buckling pressure of filament-wound cylindrical shell. First, finite element analysis was conducted to find the buckling pressure and the buckling behavior on the stacking angles of [±30/90]FW, [±45/90]FW and [±60/90]FW. The buckling formula (ASME 2007, NASA SP-8007) was employed to find the buckling pressure. These results were compared and verified through hydrostatic pressure buckling experiments. Second, the values of buckling formula and buckling pressure values of finite element analysis were compared, while the stacking angle was made to change by 5 degrees from 20 to 70 degrees. According to the conducted finite element analysis, stacking property showed the safety factor of about 1.0 at the buckling pressure values of such filament-wound stacking angles as [±30/90]FW, [±45/90]FW, and [±60/90]FW. ASME 2007 buckling formula showed the safety factor ranging from 1.84 to 2.76. On comparison, the values of the NASA SP-8007 formula showed relatively low safety factors ranging from 1.2 to 1.45. When it comes to the result to which various stacking angles from 20 to 70 degrees were applied, the values to which an equivalent material property was applied showed safety factors ranging from 0.8 to 0.97 while the ASME 2007 and the NASA SP-8007 buckling formula values showed safety factors ranging from 1.7 to 2.9 and 0.8 to 1.4 respectively. Based on the result above, the ASME 2007 formula, a simplified version of the NASA SP-8007 formula is regarded as a buckling formula in which more reliable safety factors are considered.

The objective of this paper is to predict the buckling pressure of a composite cylindrical shell using buckling formulas (ASME 2007, NASA SP 8007) and finite element analysis. The model in this study uses a stacking angle of [0/90]12t and USN 125 composite material. All specimens were made using a prepreg method. First, finite element analysis was conducted, and the results were verified through comparison with the hydrostatic pressure buckling experiment results. Second, the values obtained from the buckling formula and the buckling pressure values obtained from the finite element analysis were compared as the stacking angle was changed in increments from to . The linear and nonlinear results of the finite element analysis were consistent with the results of the experiment, with a safety factor of 0.85-1. Based on the above result, the ASME 2007 formula, a simplified version of the NASA SP-8007 formula, is regarded as a buckling formula that provides a reliable safety factor.

*Department of Precision Mechanical Engineering, Pusan National University, Busan, Korea**Pusan Educational Center for Computer Aided Machine Design, Pusan National University, Busan, KoreaKEY WORDS: Windpower system structure 풍력시스템 구조물, Composite shell 복합재 셸, Ply orientation 적층방향, Lamination pattern 적층순서, FEM 유한 요소법ABSTRACT: The purpose of this study was to develop a buckling analysis te chnique for a windpower system structure under environmental loadings (hydrostatic pressure) using FEM. We analyzed an isotr opic material and composite material and made a comparison usin g buckling pressure formulas. First, finite element analyses for an isotro pic material (SC410) were performed to obtain the variation of buckling pressure for the number of elements and boundary conditions in a pressure-sh ell model, and the numerical results were compared with those o f existing empirical formulas. Then, additional finite element analyses ba sed on the results of the isotropic material (SC410) were perfo rmed to determine the optimum lamination angle and pattern for a composite material (URN300). The results of the FE analyses for the composite mater ial were also compared with those of existing empirical formulas. The ply ori entations (lamination angles) used in the FE analyses were 0 °, 15°, 30°, 45°, 60°, 75°, and . The lamination patterns in the FE analyses were and . T he lamination pattern was assumed to be the equivalent model of . The results of the FE analyses for the isotropic material (SC410) indicated that the optimal values for the number of elements and the bou ndary conditions were 6000 and both simply supported, respectively. The results of the FE analyses for the composite material (URN300) showed t hat the optimal ply orientation was 60°~75°교신저자 홍철현: 부산광역시 금정구 장전동 산 30, 051-510-1665, chhong@pusan.ac.kr

The main objective of this paper is to investigate the validity of the finite element method (FEM) on the buckling and post-buckling behavior of laminated composite cylindrical shells that have been subjected to an external hydrostatic pressure. In addition, a buckling pressure equation that is based on the ASME and American Bureau of Shipping (ABS) bucking equation and customized to USN125 composite material is also presented. In order to determine an application for composite material under external hydrostatic pressure, material tests were conducted for carbon–epoxy ply composite URN300 and USN125. The strength and stiffness of the fiber and resin of two composites were determined. Cylindrical panel tests were performed to investigate the behavior of post-buckling under vertical line load. Finite element analyses, using ABAQUS 6.6 code, have been performed, using a linear buckling model based on the solution of the eigenvalue problem, and a non-linear model based on the arc-length method for various cases. Furthermore, an external hydrostatic pressure test was conducted to verify numerical analysis. These results were compared with the previous results obtained by FEM on the buckling. Difference between FEM and the test result is expected to be approximately 18%.

Generally, an automobile has about 10 motors for actuators that are equipped with a cooling pan, air-conditioner, and door lock system. The shape of the motor-case is directly related to the noise and vibration of the components, so various forming processes such as deep-drawing, multi-step, and multi-forming, were developed to get higher accuracy and productivity. The multi-forming process is used in this study because it has the best productivity compared with the other forming methods. The simulation technique of motor-case forming was developed to reduce the developing time and trial-error. The manufacturing processes of a motor-case consist of plate blanking, forming, and sizing. This study is focused on the core design of the multi-forming process. The blanked plate and forming dies are modeled to two- and three-dimension and analyzed by the finite element method using a commercial software DEFORM which is based on the elastic–plastic finite element theory. Two kinds of core, a circle and an ellipse, have been designed. Because of the springback effect, the roundness of the elliptic core is better than that of the circular core. The same rule is applied to the diameter ranges (20–40 mm) and yield strength levels (175–240 MPa) of low carbon steel.

Wings for the defense industry such as fighters, missiles, and rockets should show no deformation or damage on the structure. The structures of existing wings had holes for weight reduction. The plates and frames were fixed with rivets or screws, which limited the weight reduction possible. In this study, an improvement was made in jointing methods through EB welding and laser welding. Welding strength was measured through tension testing. In addition, finite element analysis was performed for the welding process so as to deduce the optimum welding condition.

Background/Aims : Continuous renal replacement therapy (CRRT) has been widely used for treating critically ill patients with acute kidney injury (AKI). Whether CRRT is better than intermittent hemodialysis for the treatment of AKI remains controversial. We sought to identify the clinical features that can predict survival for the patients who are treated with CRRT. Methods : We analyzed the data of 125 patients who received CRRT between 2005 and 2007. We identified the demographic variables, the underlying diagnoses, the duration of CRRT, the mean arterial blood pressure (ABP) and the Simplified Acute Physiology Score (SAPS) II. The classification/staging system for acute kidney injury (AKI) was applied to all the patients, who were then divided into stage 1-3 subgroups. Results : The average age of the patients was 61.414.3 years and the mortality rate was 60% (75 of 125 patients). The survivors had a significantly higher mean ABP and a higher mean serum bicarbonate level, which were measured the day after CRRT, than the nonsurvivors (86.723.7 vs. 69.224.6 mm Hg, respectively, 21.43.5 vs. 16.45.4 mmol/L, respectively,; p

A New technique is presented to overcome difficulties encountered in designing controller based on the nonlinear derivative decoupling control approach. The method, which is limited only to a set point change, is extended to a load change(unknown disturbance). This modified method is investigated on noninteracting control of laboratory-scale mixing tanks in series both by digital simulation and by experiment using on-line microcomputer. Liquid levels and temperature in tanks mixing hot and cold water inflow streams ore controlled. The results are compared with those obtained by the instantaneously optimal control and by the Inverse Nyquist Array technique. Both simulated and experimal performances of the modified derivative decoupling controller are found to be better in comparison with those obtained by the controller based on the Inverse Nyquist Array. Further, experiments showed that the modified derivative decoupling controller reduced the interaction to a negligible level.