Automotive Materials: An Experimental Investigation of an Engine Bay Acoustic Performances

Abstract In this work an extensively experimental analysis aimed to verify the sound insulation properties of the engine bay of a commercial passenger car is carried out, evaluating the possibility to adopt different sound absorbing materials, to be applied under engine cover nylon skin, in the place of commonly used polyurethane foams. Experimental tests were performed on the vehicle at different stationary operating conditions, employing typical pressure microphones for far field measurements, according to the related prescribed standards. A limited number of materials has been initially selected through a preliminary analysis, and then employed for creating different engine cover configurations, which were subsequently tested in real engine operating conditions. For a good understanding of the obtained results, an experimental investigation through an innovative in situ impedance method aimed to assess acoustic properties of each considered material has been also performed. Among all the tested materials, only one able to ensure better acoustic performance at mid and high frequencies with respect to the already existing cover configuration, has been finally identified, after considering other selection criteria such as an adequate high temperature resistance and the most cost-effective solution. Future analyses will regard investigations on the use of additional materials, for solving problem in attenuating engine noise also at low frequencies

The difficult alliance between vegan parents and pediatrician: A case report

The number of children on a vegetarian or vegan diet is gradually increasing. If not balanced and adequately supplemented, these dietary regimes can seriously impact the growth of children. Often the pediatrician is not perceived as a figure to rely on in the event of parents’ willingness to follow an alternative diet for their child. The feeling of distrust of parents towards the pediatrician can be dangerous for the health of the child. We present a 22-month-old boy with failure to thrive probably induced by an unbalanced vegetarian diet. The acquisition of the anamnestic data concerning the child’s diet was difficult because initially omitted by the parents. The poor compliance and the difficult follow-up highlights the difficulty in establishing a therapeutic alliance between parents who follow alternative regimens and the pediatrician

Numerical and Experimental Acoustic Performance Investigations of a High-Speed Train Composite Sandwich Panel

Present work focuses on the implementation of numerical and experimental analyses aimed to acoustic performances characterization of a composite sandwich panel used for a high-speed train. Firstly, an experimental and a numerical modal analyses are presented. Starting from both FE simulation and impact testing outcomes, it has been possible to carry out a correlation study through the computation of the Modal Assurance Criterion (MAC). Good agreement between numerical and experimental analyses has been found, therefore the definition of a reliable FE model has been obtained without the necessity of implementing a sensitivity and updating procedure. In this paper, to find a convenient and accurate mean for predicting the panel Transmission Loss parameter, the panel is modeled as a composite sandwich panel, and its TL is predicted with the hybrid FE&SEA (Statistical Energy Analysis) method. The TL result is then compared to the experimental one, carried out through the employment of an intensity sound probe. A very good accordance has been found allowing to use such numerical procedure for further acoustic performances improvements. Hence, future developments could regard the possibility to implement a Reverse Engineering procedure, in order to realize an optimization process by considering different materials and stratifications or different panel thicknesses, to improve the acoustic attenuation properties at those frequencies at which a worse acoustic behavior of the panel, is present

Source scaling of intermediate-depth Vrancea earthquakes

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effectiveness of switching therapy from complexing protein containing botulinum toxin type a to a formulation with low immunogenicity in spasticity after stroke a case report

Objective: some patients receiving botulinum toxin type a therapy develop immunological resistance due to the production of neutralizing antibodies against the neurotoxin, thus partially or completely reducing the therapeutic effect. Case report: We report here neurophysiological and clinical findings for a 58-year-old man treated with botulinum toxin type A for spasticity after ischaemic stroke, who became a secondary non-responder patient. subsequent treatment with a different preparation of botulinum toxin type A had a great therapeutic effect on his spasticity. the muscles injected and the dosages were the same for each treatment, but evaluation with the Modified Ashworth Scale after treatment with the second preparation showed a reduction of approximately 2 points compared with the first examination. The clinical results were also supported by extensor digitorum brevis testing of the right muscle, which showed a reduction in compound muscle action potential, whereas it was unchanged in the non-injected muscle. No side-effects were reported, and after 1 year of treatment with this formulation clinical benefits were still evident. Conclusion: the neurophysiological and clinical results obtained in this patient suggest that switching therapy from a complexing protein-containing product to a product potentially free of complexing proteins, which has low immunogenicity, may be a viable therapeutic option in secondary non-responder patients

Vegetarian and vegan weaning of the infant: How common and how evidence-based? a population-based survey and narrative review

Background: Vegetarian and vegan weaning have increasing popularity among parents and families. However, if not correctly managed, they may lead to wrong feeding regimens, causing severe nutritional deficiencies requiring specific nutritional support or even the need for hospitalization. Aim: To assess the prevalence of vegetarian and vegan weaning among Italian families and to provide an up-to-date narrative review of supporting evidence. Materials and methods: We investigated 360 Italian families using a 40-item questionnaire. The narrative review was conducted searching scientific databases for articles reporting on vegetarian and vegan weaning. Results: 8.6% of mothers follow an alternative feeding regimen and 9.2% of infants were weaned according to a vegetarian or vegan diet. The breastfeeding duration was longer in vegetarian/vegan infants (15.8 vs. 9.7 months; p < 0.0001). Almost half of parents (45.2%) claim that their pediatrician was unable to provide sufficient information and adequate indications regarding unconventional weaning and 77.4% of parents reported the pediatrician’s resistance towards alternative weaning methods. Nine studies were suitable for the review process. The vast majority of authors agree on the fact that vegetarian and vegan weaning may cause severe nutritional deficiencies, whose detrimental effects are particularly significant in the early stages of life. Discussion and conclusion: Our results show that alternative weaning methods are followed by a significant number of families; in half of the cases, the family pediatrician was not perceived as an appropriate guide in this delicate process. To date, consistent findings to support both the safety and feasibility of alternative weaning methods are still lacking. Since the risk of nutritional deficiencies in the early stages of life is high, pediatricians have a pivotal role in guiding parents and advising them on the most appropriate and complete diet regimen during childhood. Efforts should be made to enhance nutritional understanding among pediatricians as an unsupervised vegetarian or vegan diet can cause severe nutritional deficiencies with possible detrimental long-term effects

ACOUSTIC ANALYSIS OF SWALLOWING SOUNDS: A NEW TECHNIQUE FOR ASSESSING DYSPHAGIA

Objective: To perform acoustic analysis of swallowing sounds, using a microphone and a notebook computer system, in healthy subjects and patients with dysphagia affected by neurological diseases, testing the positive/negative predictive value of a pathological pattern of swallowing sounds for penetration/aspiration. Design: Diagnostic test study, prospective, not blinded, with the penetration/aspiration evaluated by fibreoptic endo scopy of swallowing as criterion standard. Subjects: Data from a previously recorded database of normal swallowing sounds for 60 healthy subjects according to gender, age, and bolus consistency was compared with those of 15 patients with dysphagia from a university hospital referral centre who were affected by various neurological diseases. Methods: Mean duration of the swallowing sounds and postswallowing apnoea were recorded. Penetration/aspiration was verified by fibreoptic endoscopy of swallowing in all patients with dysphagia. Results: The mean duration of swallowing sounds for a liquid bolus of 10 ml water was significantly different between patients with dysphagia and healthy patients. We also described patterns of swallowing sounds and tested the negative/positive predictive values of post-swallowing apnoea for penetration/aspiration verified by fibreoptic endoscopy of swallowing (sensitivity 0.67 (95% confidence interval 0.24–0.94); specificity 1.00 (95% confidence interval 0.56–1.00)). Conclusion: The proposed technique for recording and measuring swallowing sounds could be incorporated into the bedside evaluation, but it should not replace the use of more diagnostic and valuable measures

New infrastructure for studies of transmutation and fast systems concepts

In this work we report initial studies on a low power Accelerator-Driven System as a possible experimental facility for the measurement of relevant integral nuclear quantities. In particular, we performed Monte Carlo simulations of minor actinides and fission products irradiation and estimated the fission rate within fission chambers in the reactor core and the reflector, in order to evaluate the transmutation rates and the measurement sensitivity. We also performed a photo-peak analysis of available experimental data from a research reactor, in order to estimate the expected sensitivity of this analysis method on the irradiation of samples in the ADS considered