161,985 research outputs found
[Report to Chief J. E. Curry, by an unknown author #1]
No full textReport to Chief J. E. Curry, by an unknown author. The report contains a list of officers who gave depositions to the United States Attorney
[Report to Chief J. E. Curry, by an unknown author #2]
No full textReport to Chief J. E. Curry, by an unknown author. The report contains a list of officers who gave depositions to the United States Attorney
Sound Absorption of Polyimide Foams, an Experimental Study
No full textPolyimide foam panels have emerged as advanced solutions in naval, nautical, aeronautical, and railway industries, overcoming limitations associated with the high densities and thicknesses of traditional thermal and acoustic insulation materials. This study aims to experimentally characterize the sound absorption coefficient of both standard and mechanically crushed polyimide foams within the 200-4300 Hz frequency range, utilizing the Standing Wave method with three microphones. Thermally cut samples, designed for thermal insulation, show significant absorption in high-frequency ranges but are less effective at lower frequencies. Remarkably, the mechanical compression of these samples transforms closed pores into open and interconnected structures, substantially enhancing absorption at lower frequencies. This phenomenon is also observed in acoustically cut samples. Polyimide foam shows tuneable sound absorption, with the degree of enhancement dependent on variables such as the number of compression cycles, the applied force magnitude and rotational forces (not evaluated in this paper). Further investigation into these mechanical influences promises insights into optimizing the acoustic performance of polyimide-based solutions
Effects of Geometric Parameters on Sound Absorption in Perforated Plates with Elliptical Holes
No full textPerforated plates are fundamental components in sound absorption applications, often employed as resonant sound absorbers in various configurations. Typically, these configurations involve multilayer systems, where perforated plates form the initial layer. The simplest arrangement consists of a perforated plate and a backing air layer. The air mass within the holes acts as the inertial component of the resonant system, while the air backing layer serves as the restitutive force. The effective inertial mass of the perforations is subject to change based on the geometrical configuration of these systems. In contrast to conventional perforated plates with circular or square holes, elliptical perforations offer increased degrees of freedom in the geometrical configuration, with only limited systematic studies conducted to date. This study aims to systematically investigate the effects of geometrical parameters, such as form factor (eccentricity) and orientation angle, on the sound absorption characteristics of perforated plates with elliptic holes. A comprehensive experimental study was conducted using 3D-printed perforated plates. The sound absorption coefficient of the resonant system (comprising an air gap and an elliptic perforated plate) was measured in an impedance tube. Throughout the measurements, the air gap thickness was kept constant. For similar porosity and hole area, the effects of eccentricity on the sound absorption characteristics were relevant in increasing the absorption, whereas the impact of the orientation angle on the sound absorption coefficient was quite negligible with increasing the dimensions. This experimental campaign provides valuable insights into the influence of geometric parameters on the sound absorption properties of perforated plates with elliptical holes. The precise geometry of the hole pattern was identified as a crucial factor for tuning the frequency response of sound absorption systems. Future studies should expand on this research by exploring additional configurations and incorporating numerical simulations or analytical models for a more comprehensive understanding
A Transnational Perspective to Stimulate Hydrogen Penetration in Port Areas and Transform Mediterranean Ports into Sustainable Maritime Hubs
No full textThe global initiative to diminish reliance on non-renewable fuels has intensified in light of climate change imperatives. Green hydrogen, produced via renewable-powered electrolysis, is emerging as a critical solution for decarbonizing challenging sectors such as maritime transport. This paper discusses insights from the EU Interreg Marittimo-IT FR-Maritime H2MOVE project, a transnational effort to enhance green hydrogen utilization in Mediterranean ports. The project includes establishing a strategic cooperation committee, mapping the hydrogen ecosystem, analyzing legal frameworks, and developing a comprehensive “Masterplan” alongside technical feasibility studies. It emphasizes green hydrogen's vital role in reducing maritime greenhouse gas emissions while addressing pertinent technical, economic, and regulatory challenges. Key barriers include high production costs and logistical complexities. The H2MOVE project aims to provide a strategic framework for transforming Mediterranean ports into sustainable, decarbonized hubs, thereby contributing to a more environmentally friendly maritime industry
LABORATORY CHARACTERIZATION OF A MULTILAYER ACOUSTIC MATERIAL
No full textInnovative materials to accomplish thermal and sound insulation are constantly emerging from the industry. In this paper one of those innovative materials, mainly destinated to applications in environments such as yachts and ships, is characterized by means of a three-microphones impedance tube. In this way, acoustical and non-acoustical properties were either measured or extracted by means of indirect characterization. Several samples were tested and their properties were found comparable to commonly used foams and porous materials, showing the applicability of this composite material to sound insulation problems in particular environments such as the ones of transportation systems, where non-combustibility, effectiveness and low weight are essential charachteristics
A methodology to evaluate the optimal insulation thickness for heating and cooling needs in different climatic zones for buildings made of reinforced concrete with cavity walls
No full text: The study aims to define a methodology to evaluate the optimal insulation thickness with reference to the annual energy balance, including both heating and cooling seasons, for different climatic zones, based on three real case studies. The reduction of the heating needs due to the insulation of walls in places with cold climates is a consolidated concept. However, the effects of a high level of insulation of the envelope on the cooling needs has not yet been deeply analysed. The heating and cooling needs have been computed according to UNI/TS 11300 Italian standard by means of a commercial numerical model, varying the sizes of the buildings, the climatic zone, and the level of insulation. All the simulations concern buildings made of reinforced concrete frames with cavity walls, because of their wide diffusion as typical building technology of post war constructions. The work highlights the negative impact of the coating on the cooling needs, especially in the climatic zones with lower degree days. In almost all the climatic zones, the cooling need decreases its peaks during the hottest months (e.g., July or August), while the monthly load increases in the mild months (e.g., May, September) due to the additional thermal load which is no longer dispersed by means of the envelope. In conclusion, a range of optimal thicknesses for insulation for the different Italian climatic zones has been identified based on the total energy need of the building (cooling and heating)
Murder on the mountain: author talk with Peter J. Wosh
No full textAuthor talk by Peter J. Wosh on May 5th, 2022, on his book, "Murder on the Mountain: crime, passion, and punishment in gilded age New Jersey.
Mr. Melvin J. Collier, RWWL AUC, June 2011
No full textThis video is a conversation with Mr. Melvin J. Collier. Mr. Collier talks about his book, "From Mississippi to Africa: A Journey of Discovery". Daniel Le, AUC Woodruff Library, is the interviewer
A Tripartite Post-Recession Rebalancing
No full textIn this latest Advance & Rutgers Report, entitled “A Tripartite Post-Recession Rebalancing,” Dean James W. Hughes and Professor Joseph J. Seneca deliver an incisive assessment of the current market conditions and obstacles in the path of our economic recovery. They offer a statistical cautionary tale that the private and public sector need to hear and acknowledge in order for the economy to make continued progress.This report was published as Issue Paper Number 7, November 2011, in Advance & Rutgers Report
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