Seven empirical equations were developed for the prediction of seal strength for medical device trays. A new methodology was developed and used for identifying burst and peel locations and comparing burst pressure and peel force. Multiple linear regression was used to fit 76 models, selecting the best models based on the Akaike Information Criterion (AIC) and adjusted R2 (R2 adj) value of each model. The selected models have R2 adj and prediction R2 (R2 pred) values of .83 to .94. Factors investigated for the peel force response were sealing pressure (3 levels), dwell time (3 levels), sealing temperature (3 levels), and adhesive. Additional factors investigated for the burst pressure response were restraining plate gap, and tray volume, height, length-to-width ratio and area. Polyethylene terephthalate-glycol (PETG) trays with Tyvek 1073B lids and two popular water-based adhesives were used. Trays were selected to yield three levels of area and three levels of length-to-width ratio, defining nine package configurations. Packages for burst testing were sealed under a fractional factorial design with 27 treatments. Packages for peel testing were sealed under a 17-point face-centered central composite design. Packages were tested using peel testing following the ASTM F88-07 standard and restrained burst testing with three gap distances following the ASTM F2054-00 standard. All possible subsets of the factors were evaluated, with the best models selected based on AIC value. Equations were developed to predict peak and average peel force based on sealing process parameters (R2 pred =.94 and .92), burst pressure based on tray and sealing parameters and gap (R2 pred =.94), and four peel force responses based on burst pressure and gap (R2 pred =.83 to .86). Models were validated through cross-validation, using the prediction error sum of squares (PRESS) statistic. The R2 pred was calculated to estimate the predictive ability of each model.

No description available.

In this work an investigation to find new method of extraction of pectin from orange peel with shortening time of extraction is carried out. Pectin was extracted from dried orange peel at higher temperature by employing stainless steel reactors. In this investigation the effect of extraction conditions (temperature: 120, 150, 200°C; extraction time: 5, 15, 30 min) with sulphuric acid, on the yield and purity of citrus pectin was performed. Moreover, optimizing other methods of extraction and analyzing of pectin is tested. In addition, effect of adding special reagent such as Sodium polyphosphate to extract solvent examined. Furthermore, two different acids are used for extraction and the results are compared as described. Pectin is solubilized by HCl and H2SO4 at different concentrations, retention time and temperature. The effect of extraction conditions (pH: 1.5 to 2; temperature: 80 to 90°C; extraction time: 1 to 3 hours) with sulphuric acid, on the yield and purity of citrus pectin was carried out. The solubilized pectin is precipitated from the solution by using organic solvents such as 2-propanol and ethanol and then analysis was done with different methods such as carbozole and meta-hydroxy-diphenyl method. A same test was run for hydrochloric acid and comparison between them was done. / Uppsatsnivå: D

No description available.

In this study, complex rolling technology is adopted to produce aluminum/copper clad metals . The aluminum alloy A1050 and the copper C1100 are used. The experimental plan : the roughness (RCu=3.5£gm¡ARAl=6.45£gm)¡A(RCu=1.0£gm¡ARAl =2.15£gm)¡A(RCu=0.35£gm¡ARAl=0.8£gm) the thickness ratio(tAl:tCu=3:1)¡A(tAl:tCu =2:2)¡A(tAl:tCu=1:3) reduction 60% and 70% are set. It shows that the influence of the thickness is more significant than the roughness on the curvature according to the experimental results. And the results of peeling tests show that the peeling strength for the reduction 70% is larger than that for 60%. And peel strength with the second time rolling is larger than that with only once. The average peeling strength of the specimen in the rolling direction is larger than that in the perpendicular direction. From the micro Vickers hardness tests , it is known that the larger of the reduction of copper is, the larger the micro Vickers hardness between the interface of the sheets is .

This work studied the effects of step size, angle, spindle speed, and feed rate on the external surface roughening, orange peel effect, observed in single point incremental forming (SPIF). Experimental results were used to estimate models to categorize the extent of orange peel roughening based on visual inspection and on surface roughness measurements. Tests were performed at very high rotational speeds and feed rates and showed various influences on surface roughness, thickness distribution, and grain size. Friction at the tool-sheet interface was also studied with a completely instrumented tool that measured and recorded torsion and forming forces through deformation strains. Coefficients of friction for each part were determined and through statistical analysis, the influence of each of the following forming parameters was established: material thickness, formed shape, tool size, step size, forming speeds (feed rate and rotational speed), and forming angle. Multidimensional response surfaces were generated to show when and under what condition friction was minimized. A new contact zone representation for SPIF was also established. This formulation used common forming parameters and geometric considerations to determine the contacting zone between the sheet and the tool. Area models were proposed for both the tangential and torsional component of friction in SPIF. / Thesis (Master, Mechanical and Materials Engineering) -- Queen's University, 2010-02-01 16:47:17.249

Thesis (M.A.)--University of Akron, School of Dance, Theatre, and Arts Administration-Theatre Arts, 2009. / "August, 2009." Title from electronic thesis title page (viewed 10/21/2009) Advisor, James Slowiak; Faculty readers, Durand Pope, David Bush; School Director, Neil Sapienza; Dean of the College, Dudley Turner; Dean of the Graduate School, George R. Newkome. Includes bibliographical references.

Overuse of the chemical compounds and toxic elements leads to problems and transmission of contaminants and pollutants to humans and other living organisms. One of the industries’ byproducts of the agriculture sector is production of various composts from the organic raw materials that the best type of which is so – called Vermicompost. In this study, effects of raw materials on qualitative and quantitative characteristics of Vermicompost are discussed. To do so, sheep manure, pomegranate peels, spent mushroom compost either singly or double, triple or fourfold chopped corn, sugar beet pulp and sawdust were used. This research project was conducted in a completely randomized design experiment with 23 treatments with 3 replications. Results revealed that various bed combinations exert different effects on Vermicompost quality such that, the Vermicomposting process led to a significant decrease in electrical conductivity (EC) and a significant increase in pH in most of the culture (seed) beds. Also, the levels of Nitrogen, Phosphorous and Potassium in most treatments increased following completion of the vermicomposting process. As a result, this process can be introduced as an organic fertilizer with complete nutrients for improving chemical characteristics of agricultural wastes to usable fertilizers.

<p>The interface between two dissimilar materials often presents a challenge for materials engineers. Mismatches of moduli, coefficients of thermal expansion, surface energies and chemical functionalities can create headaches for engineers seeking to control and understand interfacial bonding. In this work, I am interested in two specific interfacial problems: the adhesion of pressure sensitive adhesive tapes to various substrates and the interface in polymer reinforced composite materials between the reinforcement phase and the matrix.</p> <p>Pressure sensitive adhesive tapes (PSATs) are an important class of materials with applications ranging from medical adhesives to roadway markings. In this work, I present a novel 90° peel fixture to be used in the evaluation of road tapes on roadway surfaces in construction zones. This modular fixture was validated on control surfaces before demonstrating the capability to test pavement marking tapes from road surfaces. Within the context of medical adhesives, I am interested in the deformation of the skin around the PSAT during peeling. By developing a model to predict this deformation, adhesives can be tailored to mitigate skin damage. I present experimental evidence indicating the independence of peeling force to the elastic modulus of the substrate along with deformation measurements of skin analogs during the removal of a medical tape. A new model for predicting the deformation of soft substrates during peel is reported based on the contact mechanics of a rectangular prism indenting an elastic half space.</p> <p>Polymer matrix composites are another category of materials which are increasingly adopted to improve performance or efficiency by reducing the weight of components. These materials offer a high specific strength but often fail catastrophically rather than gradually. Using stress responsive fluorescent molecules called mechanophores, I present a methodology to quantify stresses within the polymeric matrix near the reinforcement phase. By correlating in situ fluorescence intensity measurements during a uniaxial tensile test to stresses predicted from a finite element analysis model, a calibration was developed. This calibration was then applied to increasingly complex composite geometries. Chemically bonding these mechanophores to the interface between two materials allows for the detection of interfacial failures through fluorescence microscopy. I present a technique to synthesize interfacial spirolactam mechanophores on industrially relevant epoxy and silica material systems. I demonstrate the ability of these systems to detect failures in the system through in situ confocal microscopy during deformation.</p>

Yes / A composite silicone skin adhesive material was designed to improve its water vapor permeability to offer advantages to wearer comfort compared to existing skin adhesive dressings available (including perforated silicone and hydrocolloid products). The chemical and mechanical properties of this novel dressing were analyzed to show that it has a high creep compliance, offering anisotropic elasticity that is likely to place less stress on the skin. A participant study was carried out in which 31 participants wore a novel silicone skin adhesive (Sil2) and a hydrocolloid competitor and were monitored for physiological response to the dressings. Trans-epidermal water loss (TEWL) was measured pre- and postwear to determine impairment of skin barrier function. Sil2 exhibited a higher vapor permeability than the hydrocolloid dressings during wear. Peel strength measurements and dye counter staining of the removed dressings showed that the hydrocolloid had a higher adhesion to the participants’ skin, resulting in a greater removal of proteins from the stratum corneum and a higher pain rating from participants on removal. Once the dressings were removed, TEWL of the participants skin beneath the Sil2 was close to normal in comparison to the hydrocolloid dressings that showed an increase in skin TEWL, indicating that the skin had been highly occluded. Analysis of the skin immediately after removal showed a higher incidence of erythema following application of hydrocolloid dressings (>60%) compared to Sil2, ( / T.S. received partial funding to study skin adhesive materials from a Medical Research Council Confidence in Concept grant obtained by John Bridgeman at the University of Bradford (MC_PC_19030). Initial formulation and characterization work benchmarking the Sil2 material was funded in part by Trio Healthcare Ltd., who have had no role in the analysis or interpretation of the data presented. All data was obtained independently by staff at the University of Bradford. We also wish to thank the Royal Society of Chemistry for funding Edward Dyson’s position as a research technician via a Research Enablement Grant (E21-8346952505).