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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.

ObjectivePatient data repositories often assemble medication data from multiple sources, necessitating standardization prior to analysis. We implemented and evaluated a medication standardization procedure for use with a wide range of pharmacy data inputs across all drug categories, which supports research queries at multiple levels of granularity.MethodsThe GEMINI-RxNorm system automates the use of multiple RxNorm tools in tandem with other datasets to identify drug concepts from pharmacy orders. GEMINI-RxNorm was used to process 2,090,155 pharmacy orders from 245,258 hospitalizations between 2010 and 2017 at 7 hospitals in Ontario, Canada. The GEMINI-RxNorm system matches drug-identifying information from pharmacy data (including free-text fields) to RxNorm concept identifiers. A user interface allows researchers to search for drug terms and returns the relevant original pharmacy data through the matched RxNorm concepts. Users can then manually validate the predicted matches and discard false positives. We designed the system to maximize recall (sensitivity) and enable excellent precision (positive predictive value) with minimal manual validation. We compared the performance of this system to manual coding (by a physician and pharmacist) of 13 medication classes.ResultsManual coding was performed for 1,948,817 pharmacy orders and GEMINI-RxNorm successfully returned 1,941,389 (99.6%) orders. Recall was greater than 98.5% in all 13 drug classes, and the F-Measure and precision remained above 90.0% in all drug classes, facilitating efficient manual review to achieve 100.0% precision. GEMINI-RxNorm saved time substantially compared to manual standardization, reducing the time taken to review a pharmacy order row from an estimated 30 seconds to 5 seconds and reducing the number of rows needed to be reviewed by up to 99.99%.Discussion and ConclusionGEMINI-RxNorm presents a novel combination of RxNorm tools and other datasets to enable accurate, efficient, flexible, and scalable standardization of pharmacy data. By facilitating efficient minimal manual validation, the GEMINI-RxNorm system can allow researchers to achieve near-perfect accuracy in medication data standardization.

Objectives To examine how the COVID-19 pandemic affected the demographic and clinical characteristics, in-hospital care, and outcomes of long-term care residents admitted to general medicine wards for non-COVID-19 reasons. Methods We conducted a retrospective cohort study of long-term care residents admitted to general medicine wards, for reasons other than COVID-19, in four hospitals in Toronto, Ontario between January 1, 2018 and December 31, 2020. We used an autoregressive linear model to estimate the change in monthly admission volumes during the pandemic period (March-December 2020) compared to the previous two years, adjusting for any secular trend. We summarized and compared differences in the demographics, comorbidities, interventions, diagnoses, imaging, psychoactive medications, and outcomes of residents before and during the pandemic. Results Our study included 2,654 long-term care residents who were hospitalized for non-COVID-19 reasons between January 2018 and December 2020. The crude rate of hospitalizations was 79.3 per month between March-December of 2018–2019 and 56.5 per month between March-December of 2020. The was an adjusted absolute difference of 27.0 (95% CI: 10.0, 43.9) fewer hospital admissions during the pandemic period, corresponding to a relative drop of 34%. Residents admitted during the pandemic period had similar demographics and clinical characteristics but were more likely to be admitted for delirium (pandemic: 7% pre-pandemic: 5%, p = 0.01) and were less likely to be admitted for pneumonia (pandemic: 3% pre-pandemic: 6%, p = 0.004). Residents admitted during the pandemic were more likely to be prescribed antipsychotics (pandemic: 37%, pre-pandemic: 29%, p Conclusions and implications Better integration between long-term care and hospitals systems, including programs to deliver urgent medical care services within long-term care homes, is needed to ensure that long-term care residents maintain equitable access to acute care during current and future public health emergencies.

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.

ObjectiveLarge clinical databases are increasingly being used for research and quality improvement, but there remains uncertainty about how computational and manual approaches can be used together to assess and improve the quality of extracted data. The General Medicine Inpatient Initiative (GEMINI) database extracts and standardizes a broad range of data from clinical and administrative hospital data systems, including information about attending physicians, room transfers, laboratory tests, diagnostic imaging reports, and outcomes such as death in-hospital. We describe computational data quality assessment and manual data validation techniques that were used for GEMINI.MethodsThe GEMINI database currently contains 245,559 General Internal Medicine patient admissions at 7 hospital sites in Ontario, Canada from 2010-2017. We performed 7 computational data quality checks followed by manual validation of 23,419 selected data points on a sample of 7,488 patients across participating hospitals. After iteratively re-extracting data as needed based on the computational data quality checks, we manually validated GEMINI data against the data that could be obtained using the hospital’s electronic medical record (i.e. the data clinicians would see when providing care), which we considered the gold standard. We calculated accuracy, sensitivity, specificity, and positive and negative predictive values of GEMINI data.ResultsComputational checks identified multiple data quality issues – for example, the inclusion of cancelled radiology tests, a time shift of transfusion data, and mistakenly processing the symbol for sodium, “Na”, as a missing value. Manual data validation revealed that GEMINI data were ultimately highly reliable compared to the gold standard across nearly all data tables. One important data quality issue was identified by manual validation that was not detected by computational checks, which was that the dates and times of blood transfusion data at one site were not reliable. This resulted in low sensitivity (66%) and positive predictive value (75%) for blood transfusion data at that site. Apart from this single issue, GEMINI data were highly reliable across all data tables, with high overall accuracy (ranging from 98-100%), sensitivity (95-100%), specificity (99-100%), positive predictive value (93-100%), and negative predictive value (99-100%) compared to the gold standard.Discussion and ConclusionIterative assessment and improvement of data quality based primarily on computational checks permitted highly reliable extraction of multisite clinical and administrative data. Computational checks identified nearly all of the data quality issues in this initiative but one critical quality issue was only identified during manual validation. Combining computational checks and manual validation may be the optimal method for assessing and improving the quality of large multi-site clinical databases.

In this article, new Gibbs free energy of mixing is derived when there are specific interactions between sol- vent-solute molecules and between solute-solute molecules in binary solutions. It is asssumed that a probability of specific interactions satisfies a binomial distribution. Using this Gibbs free energy of mixing, we investigate possible types of partial miscibilities and show that Ω-shaped temperature-composition phase diagrams can exist. We calculate Ω-shaped temperature- composition phase diagram of water-2-butanol system and compare that with result calculated by the method of Hino 5 et al.

In some binary solution, closed miscibility loop of temperature-composition phase diagram occurs where both an upper critical solution temperature and a lower critical solution temperature exist. It is known that this phenomena occurs if specific interaction between molecules exists. There are several ways describing the specific interaction. In this work it is assumed that the total number of specific interactions is distributed according to binomial distribution. In this case, exact mathematical conditions for closed miscibility loop phase behavior are derived when the specific interaction is applied to reg- ular solution theory, quasichemical theory and Flory-Huggins lattice theory. And we investigated the effect of parameters on the phase diagram. The phase diagram of water-nicotine is calculated and compared with experimental data.

Using the free volume of van der Waals equation, Carnahan-Starling equation for hard spheres, Wilson equa- tion for nonrandom mixing of solution, NRTL equation and our equation, several new equations of states for pure gases are derived. Using these equations, compressibility factors for pure gases are calculated and compared with Nelson-Obert gen- eralized compressibility factor charts. The equation of states using the concept of molecular nonrandom distribution gave better results than those of molecular random distribution. This shows that the molecular nonrandom distribution makes considerable effect on the equation of states.

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.

상태방정식, 상태식, 격자 기체ABSTRACT. Using Carnahan-Starling equation for hard spheres and a lattice model with an attractive potential, a new two-parameter equation of state for pure gases is derived. Using this equation, compressibility factors are calculated and comparedwith Nelson-Obert generalized compressibility factor charts. The results show that the agreement of this equation with theexperimental Nelson-Obert charts is similar to that of Redlich-Kwong equation in the average. But parameters and terms ofthe new equation have physical meanings which are more definite than those of Redlich-Kwong equation.Key words: Equation of state, Lattice gas

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 present technology to handle end-of-life vehicles usually generates about 20–30% of the automobile shredder residue (ASR) of a new car in weight, which is disposed of via landfill or combustion at cement kilns and incinerators. Recently, surveys to compare various techniques such as pyrolysis, gasification, and melting to treat ASR with a better recycling rate have been reported. Gasification and melting processes are operated at high temperatures with the destruction of hazardous components and production of gases, mainly CO and H2, which can be utilized as fuel gas or raw chemicals after cleaning. Also the remaining slag solid portion is stable enough without being hazardous and it can be utilized as recycled material. In this study, ASR sampled from a shredding company was tested in a laboratory-scale gasification and melting process to characterize the gaseous and slag products. At higher temperatures and a lower air equivalent ratio (ER), CO, H2, and CH4 emission increased but CO2 and N2...

A plastic fraction consisting mainly of polyurethane/styrofoam waste is generated after separating valuable spare parts and metals from used electrical home appliances. In Korea, such waste is currently incinerated in cement kilns or is landfilled. However, owing to its high volatile matter content, conversion into gaseous or liquid pyrolysis products is a preferable alternative. A pyrolysis process of polyurethane and styrofoam waste from electrical home appliances was evaluated by characterizing the products generated at 500°–800°C. The para meters determined were the yields of gas, oil, and char; the characteristics of the remaining char; and the con centration of polychlorinated dibenzo-p-dioxins/polychlorinated dibenzo-furans in the product gas. As expected, the char yield decreased at higher temperatures, whereas gas and oil yields showed increasing tendency. The oil products could be used as storable fuels with a calorific value of 6000–8000 kcal/kg. Fine pores were observed in the char. The adsorption and decolorizing ability of the char were almost the same as those of activated carbon, so that pyrolysis char has potential for use as a sorbent. Further feasibility studies will be needed before utilizing pyrolysis technology to recover either fuels or usable products from polyurethane/styrofoam waste.

Performing random number simulations, we obtained an approximate distribution of the number of ways arranging molecules in a binary lattice solution of nonrandom mixing with a specific interaction. From the distribution an approximate equation of excess Gibbs energy for a binary lattice solution was derived. Using the equation, liquid-vapor equilibrium at constant pressure for 15 binary solutions were calculated and compared with the result from Wilson equation, Van Laar equation and Redlich-Kister equation.

의 일차결합에 대한 정규분포로 가정하였다. 난수모의실험을 수행하여 이 가정이 타당하다는 것을 입증하였고, 이 분포로부터 3 성분 논랜덤 혼합 격자용액의 과잉깁스에너지 에 대한 근사식을 유도하였다. 이를 이용하여 여러 3성분용액의 액체-증기 상평형 계산을 하였고 다른 식들의 계산 결과와비교하여 보았다.주제어: 논랜덤 혼합, 삼성분계, 과잉깁스에너지, 격자ABSRTACT. It is assumed for three components lattice solution that the number of ways of arranging particles ran-domly on the lattice follows a normal distribution of a linear combination of N

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%.

Performing random number simulations, we approximated that the distribution of the number of ways for arranging molecules randomly on a lattice is a normal distributon for N12, the number of interactions between the nearest neighbors of different molecules. From this distribution, an approximate equation of the excess Gibbs energy GE for a lattice solution of nonrandom mixing was derived. Using the equation, liquid-vapor equilibria of several binary solutions were calculated and compared with the calculated result of other equations.

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.

A new method that optimizes a control of hydrocarbon (HC) addition to diesel exhaust gas for HC type DeNOx catalyst system has been developed. These catalysts are called the HC-DeHOx catalyst in this paper. The system using HC-DeNOx catalyst requires a resonable quantity of hydrocarbons addition in the inlet gas of the catalyst, because the HC concentration in a diesel engine is so low that the HC is not sufficient for NOx conversion. It is expected that this study offers a robust data developing HC injection system.

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.

20 vol.% aluminum borate whisker (Al18B4O33w) reinforced AC4CH alloy composite was fabricated by squeeze casting method. The matrix is controlled its impurities, which make metal alloys, especially AC4CH alloy that is made by restraining 0.2% Iron and aluminum to make a matrix material. The perform of composite materials was made from Al18B4O33w with 5% regulated three kinds of inorganic binders, SiO2, Al2O3 and TiO2 sol, respectively and then sintered at 1373K. The composites were obtained by squeeze cast infiltration of the molten alloy to the perform. Then it was squeeze casting into the matrix. The status of adhesions of whisker perform was Observed by SEM. Micro-Vickers hardness and tensile properties at the room temperature were estimated. Al18B4O33w/ AC4CH composites containing TiO2 sol has excellent properties on tensile properties and microvickers hardness compared with the other composites without inorganic binder, containing SiO2 and Al2O3 sol inorganic binder.

Department of Chemistry, Duk Sung W omens University Seoul 132- 714, Korea (Received November 10, 2004) . , hole, free v olum e !" # $% . & van der Waals '() * Lennard-Jones 6-12 '() " + ,- '(). /0 123 $% . Flory 4-567 , Sanchez 8 Lacom be 9 , Dee 8 Walsch :; ?@A $% . B CD E Dee 8 Walsch , Mie(p,6) '(). 123 + , 9 , Lennard-Jones 6-12 '(). 123 + CF 9 . 23 LCST G4. / PS+PVME[(poly sty rene)+poly (viny l methyl ether)] HIJ K LM. NO3 PQR S3 /T% . U V +W XY Z V" /[\% . : , K LMABSTRACT. Many theories f or poly m eric liquids are based on the concepts of cell, hole, free volume or lattice etc.In the theories, van der Waals potential, L ennard-Jones 6-12 potential and their m odif ied potentials are comm only used.A n eqaution of satet theory of Flory & his coworkers, a cell theory of Dee a E = i HIJ. `a3 j XY :; 1k chain flexiblity 8 free volum e . lm Flory

The concept of a continuous lattice from the viewpoint of classical mechanics was introduced and a Lennard Jones 6 12 potential was used to modify the lattice fluid theory of Sanchez and Lacombe. Thus, a new equation of state for pure polymeric liquids was obtained. With this equation, PVT data, thermal expansivities and isothermal compressibilities of several polymeric liquids were calculated and compared with experimental values and with those of the lattice fluid theory and other theories. The new equation gave similar precision to Hole theory in the calculation of volumes thermal expansivity and isothermal compressibility and gave better agreement with the experimental data than the other theories used in the comparison.

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.

It has been shown, using the significant structure theory of liquids, that a lower critical solution temperature behavior as well as a upper critical solution temperature behavior can be expected for polymer–polymer systems and that a phase diagram of closed-loop-type in a polymer–polymer–solvent system can be possible. In this article the sublimation energy of a mixture was expressed as a quadratic form of segment surface fractions on pure components rather than that of mole fractions, and the effect of the segment surface fractions on critical compositions was explained. The calculated partial miscibilities were in good agreement with the experiment.

A method is developed for on-line noninteracting control of a nonlinear multivariable process to handle constraints on the control variables based on the derivative decoupling control approach. An extension of the proposed modified derivative decoupling control method to load changes (unknown disturbance) is also treated. This modified method is investigated for noninteracting control of laboratory-scale mixing tanks in series both by digital simulation and by experiment using an on-line microcomputer. Liquid levels and temperature in tanks mixing hot and cold water inflow streams are controlled. The results are compared with those obtained by instantaneously optimal control and by the inverse Nyquist array technique. Both simulated and experimental 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 can reduce interaction to a negligible level.

The significant structure theory of liquids has been applied to the partially miscible systems, of which the temperature-composition phase diagrams are of closed loop type. In this paper, the sublimation energy of a mixture is expressed as a quadratic form of surface area fractions of components, and the energy correction parameter between one component and the other is assumed to be a second order function of temperature for simplicity, although it is a higher order function of temperatures and compositions. The calculated partial miscibilities are in good agreement with the experiment. Considered mixture systems are water-nicotine and waterβ picoline systems.