Results 1 - 10 of 209
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[en] Highlights: • Drying kinetics characterization of granulated cork with a wide range of conditions. • Air stream temperature identified as dominant parameter in the drying experiments. • Characteristic drying rate curve with relevance for cork manufacturing industry. • Simple approach for optimal drying conditions selection after economical analysis. • Creating value from industrial bio-residues as a contribution to the circular economy. - Abstract: Granulated cork is a by-product of natural cork stoppers manufacturing which is incorporated into highly valued products such as agglomerated cork stoppers and expanded cork insulation. Prior to this, the cork granules must be dried. This work presents an experimental study for the characterization of wet granulated cork drying kinetics with different morphologies: a powder and granules with different sizes (2–2.8, 2.8–4 and 4–5.6 mm). A drying process with hot air stream flowing tangentially to the solid was used for a systematic analysis of the influence of air stream conditions (temperature and flowrate) on drying kinetics. Under these conditions, the influence of the stream temperature was much more relevant than its velocity with the drying time almost halving when the temperature rose from 35.0 °C to 56.5 °C. The drained humid solid with higher granulometry was dried entirely during a falling drying rate period. All others products presented a constant drying rate period before the falling drying rate period. The results revealed that the falling drying rate period is conditioned by water migration through the solid and presents a similar shape for all products. Thus, the behavior can be described by a single characteristic drying curve, allowing predicting drying rate as a function of the solid normalized humidity, despite the cork granules dimensions. This normalized curve is a useful tool for dryer equipment dimensioning in the cork manufacturing industry. To predict the time of drying for defined air drying conditions, a simple procedure was proposed using the characteristic drying rate obtained.
[en] The effect of controlled humidity protection (CHP) on aircraft operated at Seosan area was studied. Aircraft with CHP showed less variation in relative humidity (RH) than non-CHP aircraft, but the RH of avionics bay of both cases were lower than external RH. Corrosion severity index (CSI) based on ISO 9223 was measured. The CSI of an aircraft shelter was moderate. Failure data were collected and analyzed for 93 line replaceable units (LRUs). Among 93 LRUs, 5 LRUs were analyzable, and only one LRU had a significantly higher mean time between failure (MTBF) due to CHP. As a conclusion, the effect of CHP on aircraft at Seosan was not an effective measure of corrosion protection.
[en] The objective of this study is to develop a simulation model of polymer desorption under on-car experimental conditions, which is one of the main factors in condensation phenomena for automotive headlamp, and to verify its accuracy by comparison with experimental results. The numerical model is composed of the species transport equation for absolute humidity, and the water film thickness equation for evaporation and condensation. To apply the temperature boundary conditions on the walls inside the headlamp as the on-car test conditions, a time-dependent average temperature is utilized to simplify the numerical simulation. The Arrhenius type flux obtained using the Karl– Fischer Titration instrument is used for the polymer desorption on the headlamp walls for the species transport equation. The numerical average absolute humidity is compared with the experimental absolute humidity taken at a specific location. The results showed that the absolute humidity decreases sharply, i.e., when condensation occurs inside the headlamp, at the same time in the simulations and experiments.
[en] In spite of the fact that gypsum is one of the most environmentally friendly binders, utilization of gypsum products is relatively narrow. The main problem of gypsum materials is their low resistance to the wet environment and radical decrease of mechanical properties with increasing moisture. The solution of the problem could be in use of composed gypsum-based binders, usually ternary, comprising gypsum, pozzolan and alkali activator of pozzolan reaction. These materials have a better moisture resistance and often also better mechanical properties. Paper provides literature survey of the possible compositions, properties and ways of utilization of the composed gypsum-based binders with latent hydraulic and pozzolan materials together with some results of present research performed by authors. (paper)
[en] Wood as a building material has a significant perspective in the context of nonrenewable energy sources and production of greenhouse gas emissions. The subject of this paper is to verify the carrying capacity of the timber element using the probabilistic method Simulation Based Reliability Assessment (SBRA). The simulation is performed for one million cycles. Key factors decreasing the strength of wooden material at the time include the duration of the loads, and combinations thereof. Inconsiderable factor affecting the strength of wood is also the humidity. Continuous beam with three fields (length 15 m, glued laminated timber, and strength class GL 36 according to the DIN EN 1194) is placed in an environment with a thermal-humidity regime of the 2nd class according to the EC 5. Average life of carrying timber structure is estimated to be 50 years. The simulation results show that there is no risk of failure of wood during the first year. The probability of failure is common in the 10 years of its life. Then, wooden element already meets only a reduced level of reliability. (paper)
[en] Chiller Systems of Radioactive Waste Technology Center has been operated nearly 30 years, so it has suffered a lot of damage can not be repaired. It must perform the replacement of key components by the method of revitalization. Revitalization must be done because spare parts were no longer exist in the market according to type and models and also for cost efficiency. The main objective of revitalization to be fulfilled cold and fresh air in the rooms Installation of Radioactive Waste-Installations and administrative space. Before conducting activity, has been conducted an analysis of the cost-efficiency, repair methods, equipment performance and analysis of the various obstacles that will be experienced in the field so revitalization of the Chiller E 62302 can be conducted. (author)
[en] For this drying system design, the leak rate and dew point temperature (DP) of the dry room according to purgeflow rate of compressed dry air was evaluated. For preventing the equipment in the room from corrosion by salt, the humidity should be controlled at a low level (DP < -40 degrres C). However, the humidity of the dry room can be out of control during blackout, since no compressed air is supplied into the room, and the drying system does not operate at the same time. Hence, in this study, based on the observed moisture trend in the dry room during blackout, a gas supply system is considered as an emergency system. In this paper, to design an emergency gas supply system, the change of DP was observed. Based on these observations, detail design such as gas capacity will be continued
[en] To further improve the application of cosmic-ray neutron sensor technology, the SWMCN Laboratory during the summer validated the footprint, effective depth and accuracy of the mobile or “backpack” version of the sensor. Through sixteen different calibrations for five research sites in Austria, located between 300 and 1700 m a.s.l., a comparison was made between the volumetric water content measured by the backpack and gravimetric measurements for different radii of influence. Results indicated similar outcomes based on a 0-75-meter footprint as compared to a 0-200 meter study suggesting that measurements by the mobile cosmic-ray neutron sensor have a footprint with a 200-meter radius (i.e. 20 hectares). The same data were also used to determine the effective depth, results showed that the effective depth is about 10 cm for volumetric water contents ranging between 30 and 60%.
[en] Few-layer black phosphorus (BP) is an emerging material of interest for applications in electronics. However, lack of ambient stability is hampering its incorporation in practical devices as it demands for an inert operating environment. Here, we study the individual effects of key environmental factors, such as temperature, light and humidity on the deterioration of BP. It is shown that humidity on its own does not cause material degradation. In fact, few-layer BP is employed as a recoverable humidity sensor. This study eliminates humidity as an active parameter in BP degradation. Hence, by simply isolating BP from light, its lifetime can be prolonged even in the presence of O2. As such, this study opens the pathway for devising new strategies for the practical implementation of BP. (paper)
[en] Zn-Al-Mg alloy galvanized steel sheets have excellent corrosion resistance and improved cut-edge corrosion resistance. Most of the galvanized steel sheets used for outdoor applications are coated again on the galvanizing layer, or after a plastic film is laminated. As the corrosion products formed by the corrosion of Zn accumulate over time, the painting film blisters and peels, which causes a significant reduction in the value of the product. In this study, the coating adhesion and corrosion resistance of a Zn-Al alloy galvanized steel sheet with Mg added were evaluated by the salt spray test. The deterioraion of the coating film was also evaluated by Electrochemical Impedance spectroscopy(EIS) measurement. A quantitative evaluation of the coating film adhesion following water penetration between the plated layer and coating film under constant temperature and humidity condition was carried out using a Scanning Kelvin Probe(SKP).