2,141 research outputs found
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Ejection Forces and Friction Coefficients from Injection Molding Experiments Using Rapid Tooling Inserts
Experiments have been performed with injection mold inserts made using solid freeform
fabrication processes in an effort to further study such applications for economic production of
small quantities of parts. Static friction coefficients were determined for HDPE and HIPS against
P-20 steel, sintered LaserForm ST-100, and stereolithography SL 5170 using the ASTM D 1894
standard. Injection mold inserts were constructed of the same three materials and were used to
inject cylindrical parts using HDPE and HIPS. Ejection forces were measured, and a model was
used to calculate ejection forces and apparent coefficients of static friction. Statistical analyses
were used to determine the effects of packing time, cooling time and packing pressure on
ejection force for the three insert types. This paper compares experimental and calculated
ejection forces, compares standard friction test results to calculated apparent coefficients of
friction, summarizes the statistical results, and comments on the feasibility of using rapid tooled
inserts for injection molding.Mechanical Engineerin
Organ failure, outcomes and deprivation status among critically ill cirrhosis patients — a one-year cohort study
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Coconut oil has less satiating properties than medium chain triglyceride oil
It is well established that the consumption of medium-chain triglycerides (MCT) can increase satiety and reduce food intake. Many media articles promote the use of coconut oil for weight loss advocating similar health benefits to that of MCT. The aim of this study was to examine the effect of MCT oil compared to coconut oil and control oil on food intake and satiety. Following an overnight fast, participants consumed a test breakfast smoothie containing 205kcal of either (i) MCT oil (ii) coconut oil or (iii) vegetable oil (control) on three separate test days. Participants recorded appetite ratings on visual analogue scales and were presented with an ad libitum lunch meal of preselected sandwiches 180min after consumption of the breakfast. The results showed a significant difference in energy and macronutrient intakes at the ad libitum meal between the three oils with the MCT oil reducing food intake compared to the coconut and control oil. Differences in food intake throughout the day were found for energy and fat, with the control having increased food intake compared to the MCT and coconut. The MCT also increased fullness over the three hours after breakfast compared to the control and coconut oils. The coconut oil was also reported as being less palatable than the MCT oil. The results of this study confirm the differences that exist between MCT and coconut oil such that coconut oil cannot be promoted as having similar effects to MCT oil on food intake and satiety
Labour efficiency on-farm
End of project reportImprovements in milking efficiency have a greater influence than any other aspect of the dairy farmers work on overall farm labour inputs (Whipp, 1992). In order to facilitate the examination of milking process labour inputs, the milking process may be divided into the following three components: herding pre and post milking (transfer of cows to and from the milking parlour); milking (milking tasks / work routines within the parlour); and washing (washing of milking machine and yard). Meanwhile, within milking specifically, the number of cows milked per operator per hour is the best measure of both the performance of the operator and the milking installation (Clough, 1978). This is affected by the following three factors: the milking times of the cows, the number and arrangement of the milking units, and the operator’s work routine (Whipp, 1992). The addition of extra milking units will only increase milking performance if the operator has idle time during milking (Hansen, 1999)
Structure-Compressive Stress Relationships in Mixed Dairy Gels
Mixed dairy gels (including a control without fat) of skim milk powder (SMP) and whey protein isolate (WPI) containing fat globules were formed by heating protein emulsions to 90°( and by acid release from glucono- 0-lactone to provide a pH of 4.3-4.4 . Fat globules with artificial protein membranes (FGAPM) were prepared by homogenization of a butter oil /water mixture in the presence of WPI while fat globules without membranes were stabili zed with polyoxyethylene sorbitan monolaurate (Tween 20). Both emulsions were added at a 4% (w/w) leve l to solutions having 3% SMP and 8.3% WPI. The gel contai ning FGAPM had significantly higher compressive streng th than the control without fat (2.4 versus 1.8 kPa , respectively) and microst ru ctural ly it was a mixed gel in which the FGAPM, casein and whey protein aggregates formed a copolymer network. Addition of fat globules without membranes led to a filled gel weaker th an the control without fat (1.4 versus 1.8 kPa, respectivel y). Bonding of the protein membrane in FGAPM to the gel network and presence of in dividually di spersed fat globules without membranes was demonstrated by trans mission electron microscopy. The difference in microstructure is proposed to be responsible for the mechanical properties of each gel
Athletic groin pain (part 1): A prospective anatomical diagnosis of 382 patients - Clinical findings, MRI findings and patient-reported outcome measures at baseline
Background: Athletic groin pain remains a common field-based team sports time-loss injury. There are few reports of non-surgically managed cohorts with athletic groin pain. Aim: To describe clinical presentation/examination, MRI findings and patient-reported outcome (PRO) scores for an athletic groin pain cohort. Methods: All patients had a history including demographics, injury duration, sport played and standardised clinical examination. All patients underwent MRI and PRO score to assess recovery. A clinical diagnosis of the injured anatomical structure was made based on these findings. Statistical assessment of the reliability of accepted standard investigations undertaken in making an anatomical diagnosis was performed. Result: 382 consecutive athletic groin pain patients, all male, enrolled. Median time in pain at presentation was (IQR) 36 (16–75) weeks. Most (91%) played field-based ball-sports. Injury to the pubic aponeurosis (PA) 240 (62.8%) was the most common diagnosis. This was followed by injuries to the hip in 81 (21.2%) and adductors in 56 (14.7%) cases. The adductor squeeze test (90° hip flexion) was sensitive (85.4%) but not specific for the pubic aponeurosis and adductor pathology (negative likelihood ratio 1.95). Analysed in series, positive MRI findings and tenderness of the pubic aponeurosis had a 92.8% post-test probability. Conclusions: In this largest cohort of patients with athletic groin pain combining clinical and MRI diagnostics there was a 63% prevalence of PA injury. The adductor squeeze test was sensitive for athletic groin pain, but not specific individual pathologies. MRI improved diagnostic post-test probability. No hernia or incipient hernia was diagnosed. Clinical trial registration numberl: NCT02437942
Change in residential prices--a cross-sectional time-series analysis for the Boston metropolitan area
Thesis (M.C.P.)--Massachusetts Institute of Technology, Dept. of Urban Studies and Planning, 1991.Includes bibliographical references (leaves 202-210).by Anne E. Kinsella.M.C.P
Mini-sternotomy for aortic valve replacement reduces the length of stay in the cardiac intensive care unit: meta-analysis of randomised controlled trials
Background Mini-sternotomy for isolated aortic valve replacement aims to reduce operative trauma hastening recovery and improving the cosmetic outcome of cardiac surgery. The short-term clinical benefits from the mini-sternotomy are presumed to arise because the incision is less extensive and the lower half of the chest cage remains intact. The basic conduct of virtually all other aspects of the aortic valve replacement procedure remains the same. Therefore, similar long-term outcomes are to be expected.
Objectives To conduct a meta-analysis of the only available randomised controlled trials (RCT) in the published English literature.
Data sources Electronic search for relevant publications in MEDLINE, EMBASE and CENTRAL databases were performed. Four studies met the criteria.
Study eligibility criteria RCT comparing minimally invasive (inverted C or L (J)-shaped) hemi-sternotomy versus conventional sternotomy for adults undergoing isolated aortic valve replacement using standard cardiopulmonary bypass technique.
Methods Outcome measures were the length of positive pressure ventilation, blood loss, intensive care unit (ICU) and hospital stay.
Results The length of ICU stay was significantly shorter by 0.57 days in favour of the mini-sternotomy group (CI −0.95 to −0.2; p=0.003). There was no advantage in terms of duration of ventilation (CI −3.48 to 0.36; p=0.11). However, there was some evidence to suggest a reduction in blood loss and the length of stay in hospital in the mini-sternotomy group. This did not prove to be statistically significant (154.17 ml reduction (CI −324.51 to 16.17; p=0.08) and 2.03 days less (CI −4.12 to 0.05; p=0.06), respectively).
Limitations This study includes a relatively small number of subjects (n=220) and outcome variables. The risk of bias was not assessed during this meta-analysis.
Conclusion Mini-sternotomy for isolated aortic valve replacement significantly reduces the length of stay in the cardiac ICU. Other short-term benefits may include a reduction in blood loss or the length of hospital stay
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