1,721,677 research outputs found
Innovation trends in food drying and beverage dealcoholisation
No full textDrying is an excellent method to preserve vegetables and fruits that can add variety to meals and provide delicious and nutritious ready-to-eat crispy snacks. Drying combined with a pre-treatment appears to be a cost-effective method of preservation. Pre-treatments prior to drying have been reported to help reducing some of undesired changes such as antioxidant activity reduction, colour and textural changes, etc. Also, they reduce drying time by relaxing tissue structure and yield good quality dried products with high rehydration capacity. Among chemical pretreatments, innovative dipping solutions have been created for several vegetables and fruits. These dipping are diluted solutions (ppm) of natural components (such as trehalose, NaCl and sucrose) and do not contain chemical substances (i.e. sulphates) which may case allergenic reactions in sensitive people.
Moreover, alternative physical pre-treatment has been developed for drying berries, consisting of abrasion of the peel waxes.
Regarding wine and beer, the production of low alcohol beverages represents a new fast-growing sector due to major awareness about serious long-term effects of drinking and societal and individual vulnerability factors on alcohol consumption, together with consumers’ preferences. Various techniques are used to produce low alcohol beverages, but the main obstacle to their development is taste and quality reduction. Osmotic distillation is a gentle membrane technique suitable for partial and total dealcoholisation. An important step is the optimization of process parameters which may allow to minimize volatile compounds reduction in beverages, and apply adequate strategies to preserve the nutritional and sensory properties of the original beverages
Numerical analysis of the "ferris wheel" mice exposure system using an efficient cylindrical FDTD scheme
No full textThe objective of this study is to develop a numerical tool for characterizing the "ferris wheel" exposure system employed in a long-term study of RF exposure on mice. The "ferris wheel" is a radial cavity loaded with forty mice around its perimeter. In order to exploit the angular periodicity of the radial exposure system, we developed a Finite Difference in Time Domain (FDTD) code based on a cylindrical grid to analyze a single angular sector of the 40-mouse "ferris wheel". The singularity of the Maxwell equations in the cylindrical FDTD scheme was appropriately removed, and other suitable expedients were implemented to reduce simulation time and memory requirements. In order to estimate RF leakage, the actual openings in the radial cavity, needed to insert the mice, were considered as well. The FDTD scheme incorporates the perfectly matched layer (PML) unsplit formulation (anisotropic medium), as absorbing boundary condition. The code was validated with measurements, showing good agreement. A criterion for assessing the uniformity of the exposure is presented, together with results at 900 MHz and 1.8 GHz
A Mfie-FDTD Hybrid Method for the Evaluation of the Field Inside Metallic Enclosures with Slots
No full textRisk-targeted safety distance of reinforced concrete buildings from natural-gas transmission pipelines
No full textNatural-gas pipeline accidents mostly result in major damage even to buildings located far away. Therefore, proper safety distances should be observed in land use planning to ensure target safety levels for both existing and new buildings.
In this paper, a quantitative risk assessment procedure is presented for the estimation of the annual probability of direct structural damage to reinforced concrete buildings associated with high-pressure natural-gas pipeline explosions. The procedure is based on Monte Carlo simulation and takes into account physical features of blast generation and propagation, as well as damage to reinforced concrete columns. The natural-gas jet release process and the flammable cloud size are estimated through SLAB one-dimensional integral model incorporating a release rate model. The explosion effects are evaluated by a Multi-Energy Method. Damage to reinforced concrete columns is predicted by means of pressure– impulse diagrams. The conditional probability of damage was estimated at multiple pressure–impulse levels, allowing blast fragility surfaces to be derived at different performance limit states. Finally, blast risk was evaluated and allowed the estimation of minimum pipeline-to-building safety distances for risk- informed urban planning. The probabilistic procedure presented herein may be used for performance- based design/assessment of buildings and to define the path of new natural-gas pipeline networks
Application of an automatic tool for the planning of a cellular network in a real town
No full textAn application of an automatic tool for the planning of a cellular GSM network in a real environment is presented. The basic principles of the algorithm were previously developed by the authors, and in this paper solutions to the problems arising from its application to a real town are proposed. One of the main issues concerns the field prediction models, so two algorithms are used in the real environment: one is based on an artificial neural network (ANN), and one on the Cost231 model, modified for hilly terrain, and in both cases the position and the height of the buildings are considered in detail. The whole planning procedure is applied to the town of Ancona and the results give the optimized location of the radio base stations (RBS), the heights of their antennas, and their transmitted power
Tecniche riflettometriche per la localizzazione di guasti su cablaggi avionici
No full textThis paper analyses the performance of the Time Domain Reflectometry (TDR) when it is applied to the location of faults on avionic cables. Different types of defects, which can arise on coaxial cables, are modelled and their reflection coefficients are calculated. The results, validated by experimental data, are compared to the typical noise that affects this kind of measurement to assess the sensitivity of the technique. On the basis of these results, in order to improve the performance of TDR and locate also small faults, a new data processing technique based on the comparison with a reference measurement and the use of the statistical correlation is introduced. The analysis is then extended to other types of cables, such as multiwire and twisted cables, where the effect of cable and mismatching losses can limit the dynamic range of the measuremen
Comparison Between 18650 Lithium-ion Cells of Different Composition Subjected to Thermal Abuse
No full textLithium-ion Batteries (LIBs) are characterized by high energy and power density and long life and are currently used in many applications from portable devices to energy storage systems. These features increase safety concerns, especially when these devices are subject to thermal, mechanical, or electrical abuse. Abuse can lead to exothermic reactions of cell components and with each other, causing a rapid increase in temperature, called Thermal Runaway (TR), and pressure. The response to abuse depends on the physical-chemical characteristics of Li-ion cells, such as chemical composition and State of Charge (SOC). To study the effect of chemical composition, three different 18650 Li-ion cells were tested, i.e., Lithium Titanate Oxide (LTO), Lithium Iron Phosphate (LFP) and Lithium Nickel Cobalt Aluminium Oxide (NCA), at the same SOC (100 %). The cells were subjected to thermal abuse tests in a tubular reactor connected at the output to an online Fourier-transform infrared spectroscopy (FT-IR). All events, i.e., Current Interrupt Device (CID) activation, venting and TR, were recorded, and the gases emitted were traced back to the reactions that take place inside the cell. By comparing the response of the cells with different composition it was found that onset of TR occurs at lower temperature for NCA than the other cells (207 vs 233-234 °C), but the maximum temperature reached during TR by the NCA is higher (579 vs 310-338 °C). Regarding toxic emissions, for all three cells the values of hydrofluoric acid (HF) and carbon monoxide (CO) significantly exceed the Immediately Dangerous to Life or Health Limit (IDHL) defined by the National Institute for Occupational Safety and Health set at 30 ppm for HF and 1200 ppm for CO in 30 min, with maximum concentration of HF between 824 - 893 ppm and the maximum concentration of CO changing according to the chemistries: 231990 ppm for NCA, 140728 ppm for LTO and 97140 ppm for LFP
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