Evaluation of laminated structures for sports mouthguards

Most of the past studies have concentrated on the properties of mouthguard materials rather than their ability to protect the underlying substructure. Previous work has indicated that the incorporation of a shook absorbing layer into the sports mouthguard reduces the likelihood of injury to the head, neck and oral cavity of the wearer, The purpose of this study is to develop an optimum laminated structure that protects an easily deformable structure during an impact. Dropweight impact tests were conducted on a series of moulded samples which were circularly clamped and force-time and displacement-time plots obtained, Single thickness specimens of ethylene vinyl acetate (EVA), 1-5mm thick were compared with laminated structures of EVA, incorporating 1mm thick layers of polymethylmethacrylate (PMMA) and a silicone or synthetic rubber up to a thickness of 5mm. It was observed that the multi-layered structures exhibited less deformation thereby transmitting less of the harmful effects through the laminate. It was concluded that laminated systems for mouthguards using different materials appear to offer better protection to the wearer

Uplifted supersymmetric Higgs region

We show that the parameter space of the Minimal Supersymmetric Standard Model includes a region where the down-type fermion masses are generated by the loop-induced couplings to the up-type Higgs doublet. In this region the down-type Higgs doublet does not acquire a vacuum expectation value at tree level, and has sizable couplings in the superpotential to the tau leptons and bottom quarks. Besides a light standard-like Higgs boson, the Higgs spectrum includes the nearly degenerate states of a heavy spin-0 doublet which can be produced through their couplings to the $b$ quark and decay predominantly into \tau^+\tau^- or \tau\nu.Comment: 14 pages; Signs in Eqns. (3.1) and (4.2) corrected, appendix include

Gestion intégrée de l'eau au sein d'un bassin versant

Avec la mobilisation de toutes les ressources disponibles, l'état tunisien ne peut plus contrôler l'équilibre entre ressource en eau et usages sur la nappe de Kairouan qu'en maîtrisant la croissance de ces derniers. Cette maîtrise passe, entre autres, par le bon fonctionnement des périmètres irrigués collectifs. Une première étude est menée sur les périmètres publics irrigués pour examiner leurs réponses à une hausse des tarifications. Une autre méthode d'analyse est présentée sur un périmètre à gestion collective ; elle se fonde sur la réalisation d'un bilan hydrique par champ. Une analyse du fonctionnement réel ainsi que des simulations de rénovation du réseau ou de changement de règles de distribution permet d'ordonner l'importance des facteurs de dysfonctionnement. Cette analyse est appliquée à un périmètre irrigué de la région de Kairouan. Elle montre que la règle actuelle de distribution engendre une gestion inefficace de la pénurie, similaire à celle produite par un mauvais fonctionnement du réseau. (Résumé d'auteur

Transistor clamped five level inverter using non-inverting double reference single carrier PWM technique for photovoltaic applications

This treatise deals with transistor clamped five level inverter Using Non-Inverting Double Reference Single Carrier PWM (NIDRSC PWM) Technique. Conventional or two level inverter have drawbacks like i) Requirement of fast switching devices ii) Very high dv/dt iii) High Electromagnetic Interferences (EMI) iv) Bulky filters v) Faster heating of switches and vi) Not suitable for high voltage applications. Multilevel Inverters (MLIs) are engaged to conquer the drawbacks of conventional two levels inverter. MLIs generate an AC voltage using small voltage steps obtained with the help of DC supplies or capacitor banks. To design the proposed five level inverter 5 numbers of power control switches and 8 diodes are required. The proposed inverter circuitry is investigated by using Non-Inverting Double Reference Single Carrier PWM (NIDRSC PWM) Technique in terms of harmonics content in output waveform. Under-modulation (modulation Index =0.85), unity (modulation Index =1) and over-modulation (modulation Index =1.25) PWM signal is obtained to drive control switches. Simulation results will confirm the functionality, design and operation of the proposed MLI and NIDRSC PWM Techniqu

Prospectus, February 8, 1989

https://spark.parkland.edu/prospectus_1989/1033/thumbnail.jp

A young child with a history of wheeze

The parents of a 3-year old boy are anxious about their son who has recurring episodes of wheezing. They are frustrated that no one seems to be able to give them answers to their questions and would like a referral to a specialist. Does their son have asthma and what is the prognosis; how can the recurrent wheezing be managed and can the risk of asthma be reduced; are there lifestyle changes that could improve the environment and avoid triggers? Communication and support from the family practice team were essential. Listening to the parents' concerns, explaining the diagnostic uncertainty, being realistic about what drug treatments could achieve, and providing practical advice on inhaler use and trigger avoidance reassured the parents that there was a strategy for managing their son's wheeze. The specialist referral was postponed

Prospectus, April 9, 1989

https://spark.parkland.edu/prospectus_1989/1008/thumbnail.jp

Prospectus, April 12, 1989

https://spark.parkland.edu/prospectus_1989/1007/thumbnail.jp