نتایج جستجو برای: age based replacement

تعداد نتایج: 3627868  

Journal: :The Annals of thoracic surgery 2009
Edward L Hannan Zaza Samadashvili Stephen J Lahey Craig R Smith Alfred T Culliford Robert S D Higgins Jeffrey P Gold Robert H Jones

BACKGROUND Few studies have reported population-based outcomes for aortic valve replacement patients. METHODS Patients with severe aortic valve stenosis who underwent aortic valve replacement with or without concomitant coronary artery bypass graft surgery from January 1, 2003, to December 31, 2005, were included in the study. Statistical models were developed to identify significant risk fac...

2017
N. A. Nechval

In this chapter, an innovative model for age replacement is proposed. The costs included in the age replacement model are not assumed to be constants. For effective optimization of statistical decisions for age replacement problems under parametric uncertainty, based on a past random sample of lifetimes, the pivotal quantity averaging (PQA) approach is suggested. The PQA approach represents a s...

2013
Esa Jämsen Timo Puolakka Antti Eskelinen Pirkko Jäntti Jarkko Kalliovalkama Jyrki Nieminen Jaakko Valvanne

BACKGROUND AND PURPOSE High age is associated with increased postoperative mortality, but the factors that predict mortality in older hip and knee replacement recipients are not known. METHODS Preoperative clinical and operative data on 1,998 primary total hip and knee replacements performed for osteoarthritis in patients aged ≥ 75 years in a single institution were collected from a joint rep...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه خلیج فارس - دانشکده مهندسی 1393

in civil engineering concrete is a material combined of hydraulic cement, sand, gravel and water. gravel and sand compose 60 to 70 percent of concrete. these aggregates support compression force of concrete. cement paste acts as glue to stick grain together. in bushehr factories producing aggregates do not operate according to astm standards, so that fineness modulus (fm) of the produced sands ...

Jahangir Haghani, Marzieh Karimiafshar Molook Torabi-Parizi Pouneh Saberi

BACKGROUND AND AIM: Recurrent caries is defined as caries in the marginal edges of filled teeth and is the most common reason for restoration replacement. The aim of this study was to evaluation of recurrent caries in amalgam, resin-based restorations and crowns in bitewing radiographies in patients who attended Kerman dental radiology centers, Iran.METHODS: This cross-sectional study conducted...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تربیت مدرس - پژوهشکده مهندسی فرایند 1395

abstract: mineral scaling in oil and gas production equipment is one of the most important problem that occurs while water injection and it has been recognized to be a major operational problem. the incompatibility between injected and formation waters may result in inorganic scale precipitation in the equipment and reservoir and then reduction of oil production rate and water injection rate. ...

Journal: :بین المللی مهندسی صنایع و مدیریت تولید 0
robab hatami m.sc. graduate, industrial engineering department, isfahan university of technology ali zeinal hamadani associate professor,industrial engineering department, isfahan university of technology hamid reza karshenas assistant professor, department of electrical and computer engineering, isfahan university of technology mohammad hosein rohani m.sc. graduate, isfahan regional electric company

electric power industry have always try to provide reliable electricity to customers and at the same time decrease system costs. high voltage circuit-breakers are an essential part of the power network. this study has developed a maintenance and replacement scheduling model for high voltage circuit- breakers that minimize maintenance costs while maintaining the acceptable reliability. this mode...

Journal: :European Journal of Operational Research 1991

Today power consumption is considered to be one of the important issues. Therefore, its reduction plays a considerable role in developing systems. Previous studies have shown that approximately 50% of total power consumption is used in cache memories. There is a direct relationship between power consumption and replacement quantity made in cache. The less the number of replacements is, the less...

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