Impact properties analysis of rotationally molded polyethylene and polypropylene for a wide range of temperatures

Rotational molding is an established and growing manufacturing method for large, hollow plastic components. In this work the impact properties of rotationally molded Polyethylene (PE) and Polypropylene (PP) were tested at temperature in the range of -40 °C to 30 °C. Dynamic mechanical thermal analysis (DMTA) was performed to analyse the measured impact properties of PP and PE plastics. For PP, a very good relationship was found between peak impact strength and the loss modulus curve obtained in DMTA analysis. A relationship between density, β peak height and peak impact strength was found for PE which is different from previous findings in the literature. It is concluded that further work should focus on developing an understanding of the PE material's microstructure in order to more fully understand its impact properties

Pharmaceutical transition to non-CFC pressurized metered dose inhalers

The production of ozone-depleting chlorofluorocarbons (CFCs) was discontinued on 1 January 1996 for all uses deemed non-essential under the Montreal Protocol. However, the use of CFCs as propellants in pressurized metered dose inhalers (pMDIs) was classed as essential, providing an exemption from the agreement. Following extensive research, the hydrofluoroalkanes (HFA) 134a and 227 were identified as the only suitable replacements for CFC propellants in pMDIs.The drug delivery of pMDIs formulated with HFA 134a as a propellant and containing either salbutamol (100 μg per actuation) or fluticasone propionate (125 and 250 μg per actuation) have been assessed for dose uniformity and particle size distribution.All of the HFA 134a pMDIs delivered doses throughout the life of the canisters that were reproducible and within specified regulatory requirements. Each of the products provided an emitted dose which was within ±25% of the mean value indicating accurate and consistent dosing (93, 112 and 221 μg per metered dose for the salbutamol 100 μg and fluticasone propionate 125 and 250 μg HFA 134a pMDIs, respectively). These findings were unaffected by changing the storage orientation of the pMDI or by using the device in a manner designed to simulate typical patient use. The particle size distributions of HFA 134a pMDI doses did not differ significantly from those of the corresponding CFC pMDIs. As a result of the similar pharmaceutical performance, it is unnecessary to change the label claim dose of active drug when making the transition from a CFC to an HFA 134a pMDI for salbutamol (VentolinTM) and fluticasone propionate (FlixtideTM). A seamless transition to non-CFC pMDIs will help to maintain the confidence of patients and healthcare professionals in asthma therapy

The Impact of Multiple Concussions on the Lives of Student-Athletes

Please enjoy Volume 7, Issue 1 of the JSMAHS. In this issue, you will find Professional, Graduate, and Undergraduate research abstracts, and case reports. Thank you for viewing this 7th Annual OATA Special Edition

Using artificial neural networks and strain gauges for the determination of static loads on a thin square fully constrained composite marine panel subjected to a large central displacement

Current methods of estimating the behaviour of marine composite structures under pressure due to slamming as a result of high waves are based on trial and error or oversimplification. Normally under these conditions the nonlinearities of these structures are often neglected and in order to compensate, an overestimated safety factor is employed. These conservative approaches can result in heavier and overdesigned structures. In this paper a new semi-empirical method is proposed that overcomes some of these problems. This work involved the use of Artificial Neural Network (ANN) combined with strain gauge data to enable real-time in-service load monitoring of large marine structural panels. Such a tool has other important applications such as monitoring slamming or other transient hydrostatic loads that can ultimately affect their fatigue life. To develop this system a Glass Fibre Reinforced Polymer (GFRP) composite panel was used due to its potential for providing a nonlinear response to pressure or slamming loads. It was found the ANN was able to predict normal loads applied at different locations on the panel accurately. This method is also capable of predicting loads on the marine structure in real-time

Towards a modeling of the time dependence of contact area between solid bodies

I present a simple model of the time dependence of the contact area between solid bodies, assuming either a totally uncorrelated surface topography, or a self affine surface roughness. The existence of relaxation effects (that I incorporate using a recently proposed model) produces the time increase of the contact area $A(t)$ towards an asymptotic value that can be much smaller than the nominal contact area. For an uncorrelated surface topography, the time evolution of $A(t)$ is numerically found to be well fitted by expressions of the form [$A(\infty)-A(t)]\sim (t+t_0)^{-q}$, where the exponent $q$ depends on the normal load $F_N$ as $q\sim F_N^{\beta}$, with $\beta$ close to 0.5. In particular, when the contact area is much lower than the nominal area I obtain $A(t)/A(0) \sim 1+C\ln(t/t_0+1)$, i.e., a logarithmic time increase of the contact area, in accordance with experimental observations. The logarithmic increase for low loads is also obtained analytically in this case. For the more realistic case of self affine surfaces, the results are qualitatively similar.Comment: 18 pages, 9 figure

3–20 GHz GaN MMIC Power Amplifier Design Through a COUT Compensation Strategy

This paper presents the design approach for a compact, single-stage, wideband MMIC power amplifier. A method is proposed to compensate the output capacitance of the active device over a frequency range as wide as possible, with minimum impact on the achievable output power, that leads to a 2- element compensating network. A 3- section transformer is then adopted for a real-to-real transformation. The CW characterization shows output power higher than 32dBm and drain efficiency between 35% and 45%, over a fractional bandwidth of 148%, from 3 GHz to 20 GHz

Some recent radio talks.

Myxomatosis is losing its punch - By A. R. TOMLINSON, Chief Vermin Control Officer The results of the testing of field strains of myxomatosis just released by the Australian National University are of vital importance to every farmer in Western Australia. They show clearly that the predicted decline in the effectiveness of myxomatosis has occurred. Worse still, they reveal that the decline has been more rapid in some areas than observers anticipated. The importance of good seed in vegetable production. - By T. WACHTEL, Vegetable Adviser, Horticultural Division The seed is the foundation of the crop that eventually is to be harvested. As an American textbook on vegetable vegetable growing puts it: Within the seed coat may be locked up the key to future success or failure. A vegetable crop can be much poorer than the seed, but it cannot be better. Water conservation on the farm - By J. W. LEWIS, Irrigation Adviser, Bunbury Water conservation on the farm is becoming increasingly important in this State, and on most properties in the South-West water can be conserved easily and economically. Coupled with the use of modern spray irrigation systems, this trend may well revolutionise farming methods in years to come and lead the way to greater agricultural prosperity. Itch mite in sheep - By C. R. TOOP, Chief Veterinary Surgeon During the past 12 months there has been a sharp rise in the incidence of itch mite and many cases have been reported both from sheep markets and individual properties. The symptoms of itch mite infestation are very similar to those produced by hce but, unlike the sheep louse, the itch mite is invisible to the naked eye and the microscopic examination of scrapings taken from the skin after the wool has been closely clipped is necessary for its detection. Orchard irrigation - By J. CRIPPS, Horticultural Adviser There are no fruits grown in Western Australia which do not give larger crops if irrigated, although the majority of fruit growers do not have irrigation installations. Powdery mildew diseases in the home garden - By OLGA M. GOSS, B.Sc. Hons., Plant Pathologist Most of you will be only too familiar with the powdery mildew diseases which occur so frequently during the warmer months in your gardens. The most common plants badly affected by these diseases are grape vines, roses, hydrangeas, delphinium, Iagerstroemia and melons of various types. Cat Flu - A matter of serious concern - By J. SHILKIN, B.V.Sc, Veterinary Surgeon The importance of cats in the community is not generally realised by the public, yet severe epidemics among the feline population should be a matter of considerable concern. The presence of a reasonably large cat population in our cities is most important in keeping rat and mice numbers down to a low level, and their importance on farming properties is too well known to need any comment. Rat-borne diseases do occur m man in Australia and rats are always a potential danger as carriers and spreaders of some extremely serious diseases of man. Even good farmers can cause erosion. - By BRIAN MARSH, B.Sc. (Agric), Soil Conservation Adviser The particular aspects of soil conservation I am to discuss has not been publicised before, and the suggestions contained in this talk may be of use to you during seeding operations this year. It is often asked, Will the use of clover really prevent erosion

Quality indicators for dementia and older people nearing the end of life: A systematic review

Background: Robust quality indicators (QIs) are essential for monitoring and improving the quality of care and learning from good practice. We aimed to identify and assess QIs for the care of older people and people with dementia who are nearing the end of life and recommend QIs for use with routinely collected electronic data across care settings. // Methods: A systematic review was conducted, including five databases and reference chaining. Studies describing the development of QIs for care of older people and those with dementia nearing the end of life were included. QIs were categorized as relating to processes or outcomes, and mapped against six care domains. The psychometric properties (acceptability, evidence base, definition, feasibility, reliability, and validity) of each QI were assessed; QIs were categorized as robust, moderate, or poor. // Results: From 12,980 titles and abstracts screened, 37 papers and 976 QIs were included. Process and outcome QIs accounted for 780 (79.7%) and 196 (20.3%) of all QIs, respectively. Many of the QIs concerned physical aspects of care (n = 492, 50.4%), and very few concerned spiritual and cultural aspects of care (n = 19, 1.9%). Three hundred and fifteen (32.3%) QIs were robust and of those 220 were measurable using routinely collected electronic data. The final shortlist of 71 QIs came from seven studies. // Conclusions: Of the numerous QIs developed for care of older adults and those with dementia nearing the end of life, most had poor or moderate psychometric properties or were not designed for use with routinely collected electronic datasets. Infrastructure for data availability, combined with use of robust QIs, is important for enhancing understanding of care provided to this population, identifying unmet needs, and improving service provision