STRESS INTENSITY FACTORS AND WEIGHT FUNCTIONS FOR SEMI-ELLIPTICAL SURFACE CRACKS IN FINITE-THICKNESS PLATES UNDER TWO-DIMENSIONAL STRESS DISTRIBUTION

Abstract— A Fourier series approach is proposed to calculate stress intensity factors using weight functions for semi-elliptical surface cracks in flat plates subjected to two-dimensional stress distributions. The weight functions were derived from reference stress intensity factors obtained by three-dimensional finite element analyses. The close form weight functions derived are suitable for the calculation of stress intensity factors for semi-elliptical surface cracks in flat plates under two-dimensional stress distributions with the crack aspect ratio in the range of 0.1 ≤ a/c ≤ 1 and relative depth in the range of 0 ≤ a/t ≤ 0.8. Solutions were verified using several two-dimensional non-linear stress distributions; the maximum difference being 6%.     

Color image retrieval based on hidden Markov models

In this correspondence, a new approach to retrieving images from a color image database is proposed. Each image in the database is represented by a two-dimensional pseudo-hidden Markov model (2-D PHMM), which characterizes the chromatic and spatial information about the image. In addition, a flexible pictorial querying method is used, by which users can paint the rough content of the desired images in a query picture. Image matching is achieved by comparing the query picture with each 2-D PHMM in the database. Experimental results show that the proposed approach is indeed effective.     

Effect of shigella enterotoxin 1 (ShET1) on rabbit intestine in vitro and in vivo

The purpose of this study was to identify the optimal knot construction for interrupted dermal sutures. A synthetic braided absorbable suture, sizes 3-0 and 5-0, was selected for this evaluation. With reproducible mechanical performance tests, we determined that the construction of secure knots without ears required one additional throw as compared with secure knots with 3-mm ears. The direction of applied tension did not alter knot security, with the exception of granny knots, which required an extra throw when tension was applied parallel to the suture loop. Because interrupted dermal knot construction is accomplished without knot ears and with an applied tension parallel to the wound, one additional throw must be added to the knot to ensure knot security.     

R-Calculus for ELP:An Operational Approach to Knowledge Base Maintenance

Sme concepts used in knowledge base maintenace,such as sequence,new law,user‘s rejection and reconstructions of a knowledge base,are first introduced,and then a framework for extended logic programming(ELP)is given,where an extended logic program is equivalent to a knowledge base.A transition system called R-calculus for ELP is provided.For a given knowledge base and a user‘s rejection,the R-calculus for ELP will deduce best revisions of the base.The soundness and the completeness of the R-calculus for ELP are proved,and the R-calculus for ELP is implemented in Prolog.In addition,the research is compared with other relevant work.     

Longitudinal weight changes, length of survival, and energy requirements of long-term care residents with dementia

OBJECTIVE: We hypothesized that institutionalized patients with dementia, who frequently have feeding problems and require supervised and assisted feeding, would lose more weight during their residency than nondemented, independently functioning residents and have compromised survival. To test this hypothesis, we examined the survival and longitudinal changes in weight of two cohorts of institutionalized residents with dementia and compared these cohorts with a cohort of nondemented residents. We also measured the resting energy expenditures of a subset of the subjects with dementia as an indicator of their energy needs. DESIGN: A longitudinal cohort study with retrospective baseline chart review and subsequent follow-up of monthly weights and mortality over 4 years. SETTING: A 725-bed long-term care institution with specified levels of care. SUBJECTS: Two cohorts of residents with dementia, one consisting of subjects who required total care throughout their institutional stay (n = 31) and another group who did not initially require total care (n = 48); these were compared with a cohort with normal mentation who were functionally independent in their daily activities (n = 26). The total number of subjects was 105. MEASUREMENTS: Demographics, medical problems, and medications by chart review; functional and mental status evaluations; longitudinal monthly weights and mortality for the 48-month study period; and resting energy expenditures by indirect calorimetry. MAIN RESULTS: Residents with dementia had lower weights on admission and throughout their stay than nondemented, independently functioning residents, and they were more likely to have a weight loss of 10 lbs or more at some point during the 4-year study period. However, their mean weights did not change during the study period. The mean survival from admission of those demented residents who died was more than 3 years. Resting energy expenditures of women residents with advanced dementia were 12% lower than predicted from the Harris Benedict equations. CONCLUSION: Dementia is not necessarily associated with unremitting weight loss during institutionalization despite the frequent occurrence of feeding difficulties and temporary weight loss. This may be caused partly by the lower than expected resting energy expenditures and, hence, energy needs of affected residents as their dementia progresses. Demented residents weighed significantly less than nondemented, independently functioning residents throughout their institutional stay. Nevertheless, nursing staff are able to maintain weight and survival for extended periods even in very impaired residents.     

Effects of jumping skill training on walking balance for children with mental retardation and Down's syndrome

In the present study, we hypothesized that the enhancements obtained from the practice of jumping activity could be transferred to improve the walking balance in children with mental retardation (MR) and Down's syndrome (DS). SUBJECTS: Fourteen children with the diagnosis of MR or DS, aged 3 to 6 years, were recruited from a day care institution. They were ambulant but without jumping ability. Sixty-one non-handicapped children was used to serve as a normative comparison group. METHOD: Before the training program, the performances of walking balance, jump skills and jumping distances were assessed individually by one physical therapist. The balance sub-test in the Bruininks Oseretsky Test of Motor Proficiency (BOTMP) was administered to assess the walking balance. Motor Skill Inventory (MSI) was used to assess the qualitative levels of jumping skills. A jumping skill training lesson that included horizontal jumps and vertical jumps was designed and integrated into the educational program. The recruited children received 3 sessions of training per-week for 6 weeks. A post-training test and a follow-up test were administered to the handicapped children. RESULT: In BOTMP scores, statistical differences exited between the pre-training and post-training tests in the tested items of floor walk and beam walk. However, no significant difference was found in the items of floor stand, beam stand and floor heel-toe walk. MSI scales revealed there were significant differences between pre-training and post-training tests. There was no significant difference between the scores of post-training test and the follow-up test. DISCUSSION: The results implicated that the jumping activity might effectively evoke the automatic and dynamic postural control. Moreover, the significant improvements of the floor walk and beam walk performances might be due to the transferred effects via the practice of dynamic jumping activity. Furthermore, implications and suggestions are discussed.     

Cure of malignant ascites and generation of protective immunity by monoclonal antibody-targeted activation of a glucuronide prodrug in rats

We examined the in vivo efficacy of targeting beta-glucuronidase (betaG) to activate a glucuronide prodrug (BHAMG) of p-hydroxyaniline mustard (pHAM) at hepatoma ascites in Sprague-Dawley rats. Injection i.p. of 500 microg RH1-betaG, a conjugate formed between recombinant betaG and monoclonal antibody RH1 with specificity for an antigen expressed on AS-30D rat hepatoma cells, into rats bearing AS-30D ascites resulted in the accumulation of 54 microg conjugate per 10(9) tumor cells after 2 hr. Ascites fluid and serum contained 0.53 and 0 microg/ml, respectively, RH1-betaG 2 hr after injection of the conjugate. Conjugate binding to AS-30D cells was heterogeneous and non-saturated, as determined by flow cytometry. BHAMG was less toxic than pHAM to SD rats based on measures of animal mortality, weight loss and hematological toxicity. Treatment of rats bearing established hepatoma ascites with 500 microg RH1-betaG followed 2 hr later with a single i.p. injection of 30 mg/kg BHAMG or 3 i.p. injections of 10 mg/kg BHAMG 2, 3 and 4 hr later resulted in the cure of 6/8 and 8/8 animals, respectively. Treatment with BHAMG or pHAM alone did not produce cures, whereas treatment with a control antibody-betaG conjugate and BHAMG produced significantly greater hematological toxicity compared to treatment with RH1-betaG and BHAMG. All cured rats were completely protected from rechallenge with 2 x 10(7) AS-30D cells, indicating that successful treatment of animals induced protective immunity.     

任丘油田雾迷山油藏抽油机井系统效率初步探讨

总公司1996年对任丘雾迷山油藏抽油机井进行测试,系统效率高达51%~68%,其结果出乎意料。从影响抽油机系统效率的几大因素入手,分析出任丘雾迷山油藏抽油机井系统效率高的主要原因。任丘雾迷山油藏属裂缝性破酸盐岩油藏(即灰岩油战),由于其裂缝发育、渗透性好、油层厚度大、地层温度高、油气比小、饱和压力低等,使得抽油机井生产呈现如下特点:()大泵径,长冲程,低冲次大排量采油;(2)中浅京挂,小沉没度;(3)抽汲流体为液体单相,泵充满程度高;(4)部分井为连抽"带喷"状态,抽油系活塞底部受力大;(5)井液粘度低,油井不结蜡,摩阻损失小。由于这些特点以及近年来使用的新型节能抽油机,使得抽油机井系统效率大大高于其它油田抽油机井系统效率。