Design Curve Construction Based on Tolerance Limit Concept

2013 ◽  
Vol 135 (1) ◽  
Author(s):  
Zhigang Wei ◽  
Bilal Dogan ◽  
Limin Luo ◽  
Burt Lin ◽  
Dmitri Konson
Keyword(s):  
Worked Examples ◽  
Tolerance Limit ◽  
Limit Concept ◽  
Design Curve ◽  
Asme Code ◽  
Engineering Standards ◽  
American Society ◽  
Partition Principle ◽  
Engineering Practices ◽  
The Cost

Design curves, such as fatigue design S-N curves, are usually constructed by analyzing test data, which often exhibit large scatter. There are several methods available to construct a design curve and some of these methods, with varying degrees of conservativeness, accuracy, and simplicity, have been adopted by engineering standards, codes and guidelines, such as the American Society of Mechanical Engineers (ASME) Code. However, to meet increasing engineering demands, a simplified and user-friendly engineering method with rigorous mathematical and physical basis is still urgently needed to accurately manage the margin of safety and decrease the cost. In this paper, the current engineering practices for constructing a design curve are briefly reviewed, followed by the introduction of the tolerance limit concept because of its ability to relate the design curve well to sample size, failure probability, and confidence level. Recognizing the physical unsoundness of the hyperbolic shape of the design curves constructed with the Owen's tolerance limit approach, a new simple design curve construction method is developed based on the “equal partition principle.” Finally, the predicted results from various methods are compared and the advantage of the new method is demonstrated with several worked examples.

Design Curve Construction Based on Tolerance Limit Concept

2012 ◽  
Author(s):  
Zhigang Wei ◽  
Bilal Dogan ◽  
Limin Luo ◽  
Burt Lin ◽  
Dmitri Konson
Keyword(s):  
Worked Examples ◽  
Tolerance Limit ◽  
Limit Concept ◽  
Design Curve ◽  
Nonlinear Design ◽  
Engineering Designs ◽  
Complex Procedure ◽  
Engineering Standards ◽  
Partition Principle ◽  
Engineering Practices

The design curves, such as fatigue design S-N curves, required in engineering designs, are usually constructed by analyzing test data, which often exhibit large scatter. There are many methods available to construct a design curve and many of these methods, with varying degrees of conservativeness, accuracy, and simplicity, have been adopted by engineering standards, codes and guidelines, such as the ASME and ASTM codes and standards. However, to meet the increasing engineering demands, a simplified, user friendly engineering method with rigorous mathematical and physical basis is still urgently needed to accurately manage the margin of safety on one hand and decrease the cost on the other hand. In this paper the current engineering practices for constructing a design curve is reviewed. It is followed by the tolerance limit concept for general regression cases, because of its capability to relate the design curve to sample size, probability, and confidence level. A simple approximate solution is derived for Owen’s tolerance limit approach, which previously could be solved only with a very complex procedure. Finally, recognizing the physical unsoundness of the hyperbolic shape of the design curves constructed with the Owen’s tolerance limit approach, a new simple design curve construction method is proposed based on the “equal partition principle”. The predicted results from the new method are compared with that of other methods and the advantage of the proposed procedure over other methods is demonstrated with several worked examples. Linear design curve construction with heteroscedastic characteristics (variable variance) and nonlinear design curve are also discussed.

Processing of Adenoid and Tonsil Specimens in Children: A National Survey of Standard Practices and a Five-Year Review of the Experience at the Children's Hospital of Pittsburgh

1996 ◽  
Vol 115 (1) ◽  
pp. 94-97 ◽  
Author(s):  
Joseph E. Dohar ◽  
Jose A. Bonilla
Keyword(s):  
Microscopic Analysis ◽  
Cost Effective ◽  
Glycogen Storage ◽  
Children's Hospital ◽  
Children’S Hospital ◽  
Clinically Significant ◽  
American Society ◽  
Standard Practices ◽  
Glycogen Storage Disorder ◽  
The Cost

The best means of pathologically examining routine tonsillectomy and adenoidectomy specimens in children remains controversial. Otolaryngologists fear missing an unsuspected diagnosis. However, the cost-effectiveness of microscopic analysis, given the rare incidence of unsuspected diagnosis, is questionable. If a significant pathologic diagnosis is missed, the medicolegal implications could be significant. A questionnaire was sent to 111 members of the American Society of Pediatric Otolaryngology. Additionally, we reviewed our experience at the Children's Hospital of Pittsburgh for the 5-year span from 1989 to 1994 to determine our incidence of unsuspected pathologic diagnoses. Sixty-five questionnaires were returned (59% response rate). More than half (56%) of the respondents stated that microscopic analysis was routinely performed on all specimens, and 42% replied that only gross examination was performed, reserving microscopic examination for selected cases. Three respondents said that they discarded their specimens in the operating room. From March 1989 to October 1994, in 1985 children undergoing bilateral tonsillectomy and adenoidectomy at the Children's Hospital of Pittsburgh, no significant pathologic diagnoses were found. Twenty-seven additional children who underwent only tonsillectomy between January 1991 and October 1994 were also reviewed. One lymphoma, suspected before surgery, and a glycogen storage disorder, not suspected before surgery, were diagnosed. Therefore, in a total of 2012 children, we found only one clinically significant unsuspected diagnosis. In conclusion, we found no national consensus governing the best way to examine routine adenotonsillectomy specimens in children. Given that unsuspected diagnoses are rare, reserving microscopic analysis for specific clinical indications may be both more cost-effective and medically feasible.

Fully Plastic Failure Stresses and Allowable Crack Sizes for Circumferentially Surface Cracked Pipes Subjected to Tensile Loading

2021 ◽  
Author(s):  
Kunio Hasegawa ◽  
David Dvorak ◽  
Vratislav Mares ◽  
Bohumir Strnadel ◽  
Yinsheng Li
Keyword(s):  
Experimental Data ◽  
Bending Moment ◽  
Limit Load ◽  
Tensile Loading ◽  
Crack Size ◽  
Plastic Failure ◽  
Circumferential Crack ◽  
Asme Code ◽  
American Society ◽  
Better Than

Abstract Fully plastic failure stresses for circumferentially surface cracked pipes subjected to tensile loading can be estimated by means of limit load criteria based on the net-section stress approach. Limit load criteria of the first type (labelled LLC-1) were derived from the balance of uniaxial forces. Limit load criteria of the second type are given in Section XI of the ASME (American Society of Mechanical Engineering) Code, and were derived from the balance of bending moment and axial force. These are labelled LLC-2. Fully plastic failure stresses estimated by using LLC-1 and LLC-2 were compared. The stresses estimated by LLC-1 are always larger than those estimated by LLC-2. From the literature survey of experimental data, failure stresses obtained by both types of LLC were compared with the experimental data. It can be stated that failure stresses calculated by LLC-1 are better than those calculated by LLC-2 for shallow cracks. On the contrary, for deep cracks, LLC-2 predictions of failure stresses are fairly close to the experimental data. Furthermore, allowable circumferential crack sizes obtained by LLC-1 were compared with the sizes given in Section XI of the ASME Code. The allowable crack sizes obtained by LLC-1 are larger than those obtained by LLC-2. It can be stated that the allowable crack size for tensile stress depends on the condition of constraint of the pipe, and the allowable cracks given in Section XI of the ASME Code are conservative.

scholarly journals Postoperative Home Monitoring After Joint Replacement: Retrospective Outcome Study Comparing Cases With Matched Historical Controls (Preprint)

2018 ◽  
Author(s):  
Homer Yang ◽  
Geoff Dervin ◽  
Susan Madden ◽  
Ashraf Fayad ◽  
Paul Beaulé ◽  
...  
Keyword(s):  
Emergency Room ◽  
Descriptive Analysis ◽  
Home Monitoring ◽  
Standard Of Care ◽  
Control Group ◽  
Emergency Room Visits ◽  
American Society ◽  
Patient Readmissions ◽  
The Cost ◽  
Historical Controls

BACKGROUND A retrospective cohort study was conducted in patients undergoing postoperative home monitoring (POHM) following elective primary hip or knee replacements. OBJECTIVE The objectives of our study were to compare the cost per patient, readmissions rate, emergency room visits, and mortality within 30 days to the historical standard of care using descriptive analysis. METHODS After Research Ethics Board approval, patients who were enrolled and had completed a POHM study were individually matched to historical controls by age, American Society of Anesthesiology class, and procedure at a ratio 1:2. RESULTS A total of 54 patients in the study group and 107 in the control group were eligible for the analysis. Compared with the historical standard of care, the average cost per case was Can $5826.32 (SD 1418.89) in the POHM group and Can $9198.58 (SD 1513.59) for controls. After 30 days, there were 2 emergency room visits (3.7%) and 0 readmissions in the POHM group, whereas there were 8 emergency room visits (7.5%) and 2 readmissions (1.9%) in the control group. No mortalities occurred in either group. CONCLUSIONS The POHM study offers an early hospital discharge pathway for elective hip and knee procedures at a 38% reduction of the standard of care cost. The multidisciplinary transitional POHM team may provide a reliable forum to minimize readmissions, and emergency room visits within 30 days postoperatively. CLINICALTRIAL ClinicalTrials.gov NCT02143232; https://clinicaltrials.gov/ct2/show/NCT02143232 (Archived by WebCite at http://www.webcitation.org/73WQ9QR6P)

“Literary Institutions are Founded and Endowed for the Common Good”

2017 ◽  
Author(s):  
Charles Dorn
Keyword(s):  
Common Good ◽  
Social Institutions ◽  
Higher Learning ◽  
The Public ◽  
Regional Center ◽  
The Common ◽  
American Society ◽  
The Cost ◽  
Civic Mindedness ◽  
Primary Mission

This chapter examines Bowdoin College, which was supported by district elites who worked to erect a regional center of higher learning to which they could send their sons rather than incur the cost of dispatching them south to other colleges. On the morning of Bowdoin's opening, appointed president Joseph McKeen pronounced the college's primary mission: “That the inhabitants of this district may have their own sons to fill the liberal professions among them, and particularly to instruct them in the principles and practice of our holy religion, is doubtless the object of this institution.” This conception of higher education's function in American society drew heavily on a social ethos of civic-mindedness that assigned priority to social responsibility over individuals' self indulgence. Characterized by the practice of civic virtue and a commitment to the public good, civic-mindedness provided social institutions, including those dedicated to higher learning, a source from which to derive their central aims.

Making E-Training Cost Effective through Quality Assurance

2009 ◽  
pp. 623-631
Author(s):  
Lichia Yiu ◽  
Raymond Saner
Keyword(s):  
High Performance ◽  
Cost Effective ◽  
Web Based ◽  
Corporate Learning ◽  
Use Of Technology ◽  
Training Cost ◽  
E Learning ◽  
American Society ◽  
High Level ◽  
The Cost

Since the 1990s, more and more corporate learning has been moved online to allow for flexibility, just-in-time learning, and cost saving in delivering training. This trend has been evolved along with the introduction of Web-based applications for HRM purposes, known as electronic Human Resource Management (e-HRM). By 2005, 39.67% of the corporate learning, among the ASTD (American Society for Training and Development) benchmarking forum companies, was delivered online in comparison to 10.5% in 2001. E-learning has now reached “a high level of (technical) sophistication, both in terms of instructional development and the effective management of resources” in companies with high performance learning function (ASTD, 2006, p.4). The cost per unit, reported by ASTD in its 2006 State of Industry Report, has been declining since 2000 despite the higher training hours received per employee thanks to the use of technology based training delivery and its scalability. However, the overall quality of e-learning either public available in the market or implemented at the workplace remains unstable.

A Life-Cycle Risk-Informed Systems Structured Nuclear Code

2002 ◽  
Author(s):  
Ralph S. Hill
Keyword(s):  
Life Cycle ◽  
American Concrete Institute ◽  
Design Code ◽  
Replacement Decisions ◽  
Plant Operations ◽  
Operations And Maintenance ◽  
Asme Code ◽  
American Society ◽  
Construction Operation ◽  
Design Construction

Current American Society of Mechanical Engineers (ASME) nuclear codes and standards rely primarily on deterministic and mechanistic approaches to design. The design code is a separate volume from the code for inservice inspections and both are separate from the standards for operations and maintenance. The ASME code for inservice inspections and code for nuclear plant operations and maintenance have adopted risk-informed methodologies for inservice inspection, preventive maintenance, and repair and replacement decisions. The American Institute of Steel Construction and the American Concrete Institute have incorporated risk-informed probabilistic methodologies into their design codes. It is proposed that the ASME nuclear code should undergo a planned evolution that integrates the various nuclear codes and standards and adopts a risk-informed approach across a facility life-cycle — encompassing design, construction, operation, maintenance and closure.

A Study of Axial Compression in the ASME B&PV Code for Pipe Supports and Restraints

2016 ◽  
Author(s):  
Phillip E. Wiseman ◽  
Zara Z. Hoch
Keyword(s):  
Axial Compression ◽  
Pressure Vessel ◽  
Slenderness Ratio ◽  
Elastic Buckling ◽  
Allowable Stress ◽  
Linear Elastic ◽  
Division 1 ◽  
Asme Code ◽  
American Society ◽  
Allowable Stress Design

Axial compression allowable stress for pipe supports and restraints based on linear elastic analysis is detailed in the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code, Section III, Division 1, Subsection NF. The axial compression design by analysis equations within NF-3300 are replicated from the American Institute of Steel Construction (AISC) using the Allowable Stress Design (ASD) Method which were first published in the ASME Code in 1973. Although the ASME Boiler and Pressure Vessel Code is an international code, these equations are not familiar to many users outside the American Industry. For those unfamiliar with the allowable stress equations, the equations do not simply address the elastic buckling of a support or restraint which may occur when the slenderness ratio of the pipe support or restraint is relatively large, however, the allowable stress equations address each aspect of stability which encompasses the phenomena of elastic buckling and yielding of a pipe support or restraint. As a result, discussion of the axial compression allowable stresses provides much insight of how the equations have evolved over the last forty years and how they could be refined.

Effect of Different Cost Drivers on Cost per Anesthesia Minute in Different Anesthesia Subspecialties

2004 ◽  
Vol 101 (6) ◽  
pp. 1435-1443 ◽  
Author(s):  
Martin Schuster ◽  
Thomas Standl ◽  
Joachim A. Wagner ◽  
Jürgen Berger ◽  
Hajo Reißmann ◽  
...  
Keyword(s):  
Multiple Regression Model ◽  
University Hospital ◽  
Cost Drivers ◽  
Personnel Costs ◽  
Facial Surgery ◽  
American Society ◽  
The Cost ◽  
American Society Of Anesthesiologists ◽  
Cost Differences ◽  
Nose And Throat

Background Little is known about differences in costs to provide anesthesia care for different surgical subspecialties and which factors influence the subspecialty-specific costs. Methods In this retrospective study, the authors determined main cost components (preoperative visit, intraoperative personnel costs, material and pharmaceutical costs, and others) for 10,843 consecutive anesthesia cases from a 6-month period in the 10 largest anesthesia subspecialties in their university hospital: ophthalmology; general surgery; obstetrics and gynecology; ear, nose, and throat surgery; oral and facial surgery; neurosurgery; orthopedics; cardiovascular surgery; traumatology; and urology. Using regression analysis, the effect of five presumed cost drivers (anesthesia duration, emergency status, American Society of Anesthesiologists physical status of III or higher, patient age younger 6 yr, and placement of invasive monitoring) on subspecialty-specific costs per anesthesia minute were analyzed. Results Both personnel costs for anesthesiologists and total costs calculated per anesthesia minute were inversely correlated with the duration of anesthesia (adjusted R2 = 0.75 and 0.69, respectively), i.e., they were higher for subspecialties with short cases and lower for subspecialties with longer cases. The multiple regression model showed that differences in anesthesia duration alone accounted for the majority of the cost differences, whereas the other presumed cost drivers added only little to explain subspecialty-specific cost differences. Conclusions Different anesthesia subspecialties show significant and financially important differences regarding their specific costs. Personnel costs and total costs are highest for subspecialties with the shortest cases. Other analyzed cost drivers had little effect on subspecialty-specific costs. In the light of these cost differences, a detailed cost analysis seems necessary before the profitability of an anesthesia subspecialty can be assessed.

American Society of Clinical Oncology Guidance Statement: The Cost of Cancer Care

2009 ◽  
Vol 27 (23) ◽  
pp. 3868-3874 ◽  
Author(s):  
Neal J. Meropol ◽  
Deborah Schrag ◽  
Thomas J. Smith ◽  
Therese M. Mulvey ◽  
Robert M. Langdon ◽  
...  
Keyword(s):  
United States ◽  
Health Care ◽  
Clinical Oncology ◽  
Cancer Care ◽  
Cost Effective ◽  
The United States ◽  
Cost Of Care ◽  
High Quality ◽  
American Society ◽  
The Cost

Advances in early detection, prevention, and treatment have resulted in consistently falling cancer death rates in the United States. In parallel with these advances have come significant increases in the cost of cancer care. It is well established that the cost of health care (including cancer care) in the United States is growing more rapidly than the overall economy. In part, this is a result of the prices and rapid uptake of new agents and other technologies, including advances in imaging and therapeutic radiology. Conventional understanding suggests that high prices may reflect the costs and risks associated with the development, production, and marketing of new drugs and technologies, many of which are valued highly by physicians, patients, and payers. The increasing cost of cancer care impacts many stakeholders who play a role in a complex health care system. Our patients are the most vulnerable because they often experience uneven insurance coverage, leading to financial strain or even ruin. Other key groups include pharmaceutical manufacturers that pass along research, development, and marketing costs to the consumer; providers of cancer care who dispense increasingly expensive drugs and technologies; and the insurance industry, which ultimately passes costs to consumers. Increasingly, the economic burden of health care in general, and high-quality cancer care in particular, will be less and less affordable for an increasing number of Americans unless steps are taken to curb current trends. The American Society of Clinical Oncology (ASCO) is committed to improving cancer prevention, diagnosis, and treatment and eliminating disparities in cancer care through support of evidence-based and cost-effective practices. To address this goal, ASCO established a Cost of Care Task Force, which has developed this Guidance Statement on the Cost of Cancer Care. This Guidance Statement provides a concise overview of the economic issues facing stakeholders in the cancer community. It also recommends that the following steps be taken to address immediate needs: recognition that patient-physician discussions regarding the cost of care are an important component of high-quality care; the design of educational and support tools for oncology providers to promote effective communication about costs with patients; and the development of resources to help educate patients about the high cost of cancer care to help guide their decision making regarding treatment options. Looking to the future, this Guidance Statement also recommends that ASCO develop policy positions to address the underlying factors contributing to the increased cost of cancer care. Doing so will require a clear understanding of the factors that drive these costs, as well as potential modifications to the current cancer care system to ensure that all Americans have access to high-quality, cost-effective care.

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