sound quality analysis of the powertrain booming noise in a diesel passenger car

Abstract Among many noises which can be heard inside a car, the booming noise caused by powertrain excitation is usually considered as one of the very annoying acoustic features that affect the interior sound quality of a car. This work presents results coming from an experimental analysis carried out on a Diesel passenger car in order to evaluate the interior booming sensation related with the engine rotation and firing. Tests were performed in acceleration conditions on the vehicle installed at the chassis dynamometer, by measuring noise at the driver and passengers' positions inside cabin. A waterfall analysis was firstly carried out to see the spectral and temporal pattern of recorded time-varying sounds. In particular, the change of sound level related to the fundamental frequency of engine firing and its harmonics was assessed as a function of engine revolution per minute at each microphone location. Acquired data were properly post-processed for sound quality analysis as well, in order to have information about the degree of booming sensation in the accelerating car and to quantify the level of annoyance perceived by each car's occupant. The analysis allowed to identify the vehicle operating conditions as well as the locations inside cabin that make the passengers more exposed to the booming phenomenon. The obtained results represent a useful starting basis for selecting the most appropriate noise and vibration control strategies in vehicle sound quality optimization process

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

A technique for detecting corn hybrid susceptibility to eradicane

Call number: LD2668 .T4 1978 P35Master of Scienc

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

A web application prototype for the multiscale modelling of seismic input

A web application prototype is described, aimed at the generation of synthetic seismograms for user-defined earthquake models. The web application graphical user interface hides the complexity of the underlying computational engine, which is the outcome of the continuous evolution of sophisticated computer codes, some of which saw the light back in the middle '80s. With the web application, even the non-experts can produce ground shaking scenarios at the local or regional scale in very short times, depending on the complexity of the adopted source and medium models, without the need of a deep knowledge of the physics of the earthquake phenomenon. Actually, it may even allow neophytes to get some basic education in the field of seismology and seismic engineering, due to the simplified intuitive experimental approach to the matter. One of the most powerful features made available to the users is indeed the capability of executing quick parametric tests in near real-time, to explore the relations between each model's parameter and the resulting ground motion scenario. The synthetic seismograms generated through the web application can be used by civil engineers for the design of new seismo-resistant structures, or to analyse the performance of the existing ones under seismic load.Comment: 23 pages, 13 figure

Erratum to: Seismic waves in 3-D: from mantle asymmetries to reliable seismic hazard assessment

Acknowledgments This paper is strongly relying upon the work of many colleagues and collaborators to whom we are greatly thankful, in particular: Carlo Doglioni, Gillian Foulger, Vahid Gholami, Hossein Hamzehloo, Volodya Kossobokov, Cristina La Mura, Anatoly Levshin, Andrea Magrin, Antonella Peresan, Federica Riguzzi, Franco Vaccari, Peter Varga, Tatiana Yanovskaya. Financial support from PRIN 2010-2011 and RITMARE projects, funded by Italian Ministry of University and Research, is gratefully acknowledged. In addition, Fig. 3 should be updated by new one as below

Resectable IIIA-N2 non-small-cell lung cancer (NSCLC): In search for the proper treatment

Locally advanced non-small cell lung cancer accounts for one third of non-small cell lung cancer (NSCLC) at the time of initial diagnosis and presents with a wide range of clinical and pathological heterogeneity. To date, the combined multimodality approach involving both local and systemic control is the gold standard for these patients, since occult distant micrometastatic disease should always be suspected. With the rapid increase in treatment options, the need for an interdisciplinary discussion involving oncologists, surgeons, radiation oncologists and radiologists has become essential. Surgery should be recommended to patients with non-bulky, discrete, or single-level N2 involvement and be included in the multimodality treatment. Resectable stage IIIA patients have been the subject of a number of clinical trials and retrospective analysis, discussing the efficiency and survival benefits on patients treated with the available therapeutic approaches. However, most of them have some limitations due to their retrospective nature, lack of exact pretreatment staging, and the involvement of heterogeneous populations leading to the awareness that each patient should undergo a tailored therapy in light of the nature of his tumor, its extension and his performance status

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

Engineering robust next-generation networks

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