190,165 research outputs found
Experimental determination and control of prepreg tack for automated manufacture
No full textThe automated tape laying (ATL) process has been examined and found to be sensitive to tack and stiffness properties of the prepreg material being laid. A comparison of existing aerospace and newly developed ATL prepreg tapes has revealed significant differences in tack response to temperature and feedrate. Examination of constituent resin rheology has found that tack, and the two observed failure modes, are somewhat dependent upon viscoelastic stiffness. Observation of temperature and feedrate response revealed a time–temperature superposition relationship. The Williams–Landel–Ferry equation was utilised to make predictions of the temperature response based on the feedrate response. Tack levels were stabilised over the feedrate range by making temperature adjustments. Results from the peel test, where mould conditions at lay-up were recreated, were found transferable to the ATL, where a suitable lay-up feedrate under ambient conditions was predicted
The experimental determination of prepreg tack and dynamic stiffness
No full textA new peel test has been developed which quantifies the tack and dynamic stiffness of uncured prepreg. The test is designed to simulate the automated tape lay-up (ATL) and automated fibre placement (AFP) processes. It includes a pressure controlled application stage, where contact time is inversely proportional to peel rate. The use of a thin film allows stiffness to be isolated from peel resistance in a continuous two stage test. A repeatability study revealed consistent results with 16% standard deviation. Tack and stiffness variability has been observed across roll width and between faces in commercial hand lay-up prepregs. The overall tack and stiffness values for commercial hand lay-up prepregs were found to be inconsistent with the levels specified by manufacturers. A temperature increase revealed inconsistent effects on tack between materials. The contradictory results were rationalised by observing failure modes. The two failure modes observed appeared equivalent to those found in pressure sensitive adhesive (PSA) peel. The shear storage modulus of the prepreg resin was compared to the PSA Dahlquist criterion and found to support the principle of contact efficiency. However, the actual value for the criterion is expected to be a function of prepreg specific conditions such as resin content, fibre distribution and surface pattern
Human in vivo studies on the non-glycaemic effects of thiazolidinedione derivatives
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132629.pdf (Publisher’s version ) (Open Access)Radboud Universiteit Nijmegen, 18 december 2014Promotores : Smits, P., Tack, C.J.J
tack
No full texttack"Sew on your back and you'll never have a tack." _ If a you sew something xxx while it's on you you're/careless p erson.DNE-citJH 4/70Used I and SupUsed I and SupUsed
Metabolic and vascular effects of AICA-riboside in humans
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87713.pdf (Publisher’s version ) (Open Access)Radboud Universiteit Nijmegen, 11 november 2010Promotores : Tack, C.J.J., Smits, P. Co-promotor : Loon, L.J.C. van157 p
Impaired awareness of hypoglycaemia in type 1 diabetes. Prevalence, genetic predisposition and mortality
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183427.pdf (Publisher’s version ) (Open Access)Radboud University, 21 maart 2018Promotores : Smits, P., Tack, C.J.J. Co-promotor : Galan, B.E. d
Tack Coat Installation Performance Guidelines
No full textUS Transportation Collectionhttps://doi.org/10.5703/12882843167902018PDFTech ReportMcDaniel, Rebecca S.Shah, AyeshaLee, JusangPurdue University. Joint Transportation Research ProgramIndiana. Dept. of Transportation. Division of Research and DevelopmentUnited States. Department of Transportation. Federal Highway AdministrationPurdue University. Joint Transportation Research ProgramIndianaUnited StatesGuidelinesInstallationPerformance measurementSealing compoundsTack coatsSpecificationsSpray paverFHWA/IN/JTRP-2018/18SPR-3904Final ReportA tack coat is a thin application of asphalt (typically emulsified) used to bond pavement layers together so that they act monolithically. Lack of bonding can lead to fatigue cracking, delamination, slippage and other distresses. This study was undertaken to explore the impacts of various tack coat materials, application rates, and other variables on tack coat performance. The ultimate original goal was to develop a tack coat quality acceptance system. As the study progressed, some of the original objectives and tasks were modified or dropped. Laboratory testing of lab- and field-fabricated specimens using a monotonic direct shear test was used to evaluate the factors of interest. The findings showed that the most commonly used tack materials in Indiana, AE-NT and SS-1h, can perform, with the AE-NT exhibiting somewhat better performance overall. INDOT\u2019s tack specifications could be clarified. The current applications rates are reasonable but could be refined to provide more guidance for use on different types of surfaces, as widely recommended nationally. The use of spray pavers and alternate tack materials should be further explored. Planned spray paver trial projects could provide the opportunity to expand on the results of this project, to explore other test methods, gain more experience with shear testing, and assess typical tack applications on non-experimental projects to assess the state of the practice. Additional implementation studies may help to refine a performance test and criteria for use to assess tack coat quality. The importance of tack coats should be emphasized to contractors and field personnel.133
Assessment of insulin-stimulated glycogen synthesis by magnetic resonance spectroscopy. Studies in skeletal muscle of healthy versus insulin resistant humans.
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59245.pdf (Publisher’s version ) (Open Access)KUN Katholieke Universiteit Nijmegen, 01 november 2004Promotores : Heerschap, A., Smits, P. Co-promotor : Tack, C.J.J.130 p
Field tack coat evaluator (ATACKer).
No full textAsphalt tack coats are applied during pavement construction to ensure bond between pavement layers, thus providinga more durable pavement. A prototype tack coat evaluation device (TCED) was developed to evaluate the tensile andtorque-shear strength of tack coat materials. Three emulsions (SS-1, CSS-1, and CRS-2) and one asphalt binder (PG67-22), commonly used as tack coats, were evaluated using the TCED at various application temperatures, applicationrates, dilutions, and set times. A laboratory bond interface strength device (LBISD) was developed to assess interfaceshear strength of laboratory prepared specimens. Mass loss testing was performed to evaluate moisture evaporationand visual breaking properties of emulsions.Study results indicate application rate, tack coat, and emulsion set time significantly affect TCED strength.Application rate also affected evaporation rate of emulsions
Effect of the GLP-1 analog liraglutide on satiation and gastric sensorimotor function during nutrient-drink ingestion.
No full textBackground/Aim:Liraglutide, a glucagon-like peptide-1 analog, induces weight loss. We investigated whether liraglutide affects gastric accommodation and satiation by measuring the intragastric pressure (IGP) during nutrient-drink consumption and using the barostat technique.Methods:Ten healthy volunteers (HVs) were tested after placebo, 0.3, 0.6 or 1.2 mg liraglutide administration. IGP was studied during intragastric nutrient-drink (1.5 kcal ml(-1)) infusion (60 ml min(-1)), while the HVs scored their satiation on a graded scale until maximal satiation. In a separate session, isobaric distentions were performed using the barostat with stepwise increments of 2 mm Hg starting from minimal distending pressure, although HVs scored their perception; gastric volume was monitored 30 min before and until 60 min after ingestion of 200 ml of nutrient drink. Data are presented as mean±s.e.m. comparisons were performed with ANOVA (P<0.05 was significant).Results:During nutrient-drink infusion, IGP decreased with 4.1±0.7, 3.0±0.4, 2.1±0.3 and 2.6±0.4 mm Hg (placebo, 0.3, 0.6 and 1.2 mg liraglutide, respectively; P<0.05). The maximum-tolerated volume was not different, except after treatment with 1.2 mg liraglutide (695±135 ml) compared with placebo (1008±197 ml; P<0.05); however, 1.2 mg liraglutide induced nausea in all volunteers. In the barostat study, liraglutide did not affect the perception or compliance, but significantly decreased gastric accommodation to the meal (168±27 vs 78.8±36.4 ml after treatment with placebo and 0.6 mg liraglutide, respectively; P<0.05).Conclusion:Although no effect on perception, compliance or satiation was observed, liraglutide inhibited gastric accommodation. Whether this effect is involved in the anorectic effect of liraglutide remains to be determined
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