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1
Gonzalez, Mireia Bargallo, Erik Rosseel, Andriy Hikavyy, Tatiana Fernandez-Lanas, Geert Eneman, Peter Verheyen, Roger Loo, Eddy Simoen, and Cor Claeys. "Stress Analysis and Junction Leakage of Sub-Melt Laser Annealed SiGe Epitaxial Layers." IEEE Transactions on Semiconductor Manufacturing 23, no. 4 (November 2010): 538–44. http://dx.doi.org/10.1109/tsm.2010.2050789.
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Hier-Majumder, Saswata, Maxim D. Ballmer, Matthew Agius, Catherine Rychert, and Nicholas Harmon. "Evidence for melt leakage from the Hawaiian plume above the mantle transition zone." Physics of the Earth and Planetary Interiors 321 (December 2021): 106813. http://dx.doi.org/10.1016/j.pepi.2021.106813.
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Marschik, Christian, Wolfgang Roland, Marius Dörner, Georg Steinbichler, and Volker Schöppner. "Leakage-Flow Models for Screw Extruders." Polymers 13, no. 12 (June 9, 2021): 1919. http://dx.doi.org/10.3390/polym13121919.
Повний текст джерелаАнотація:
Many theoretical analyses of extrusion ignore the effect of the flight clearance when predicting the pumping capability of a screw. This might be reasonable for conventional extruder screws with “normal” clearances but leads to errors when more advanced screw designs are considered. We present new leakage-flow models that allow the effect of the flight clearance to be included in the analysis of melt-conveying zones. Rather than directly correcting the drag and pressure flows, we derived regression models to predict locally the shear-thinning flow through the flight clearance. Using a hybrid modeling approach that includes analytical, numerical, and data-based modeling techniques enabled us to construct fast and accurate regressions for calculating flow rate and dissipation rate in the leakage gap. Using the novel regression models in combination with network theory, the new approximations consider the effect of the flight clearance in the predictions of pumping capability, power consumption and temperature development without modifying the equations for the down-channel flow. Unlike other approaches, our method is not limited to any specific screw designs or processing conditions.
4
Kłodowski, Adam, Harri Eskelinen, and Scott Semken. "Leakage-proof nozzle design for RepRap community 3D printer." Robotica 33, no. 4 (March 10, 2014): 721–46. http://dx.doi.org/10.1017/s0263574714000502.
Повний текст джерелаАнотація:
SUMMARYThe RepRap 3D printer development project is a fast growing, open-hardware initiative relying on the input of hobbyist designers. One of its key components is the printer nozzle. The performance and reliability deficiencies of currently available nozzle designs are common topics in the RepRap community, and our own experience with a RepRap 3D printer has identified a need for improvement in a few particular areas. We set out to eliminate melt leakage, improve thermal isolation, and develop a more effective method of nozzle assembly attachment. Here, we review the issues, describe design efforts, and report results.
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Marschik, Christian, Wolfgang Roland, and Tim A. Osswald. "Melt Conveying in Single-Screw Extruders: Modeling and Simulation." Polymers 14, no. 5 (February 23, 2022): 875. http://dx.doi.org/10.3390/polym14050875.
Повний текст джерелаАнотація:
Numerous analyses have modeled the flow of polymer melts in the melt-conveying zones of single-screw extruders. While initial studies mainly provided exact analytical results for combined drag and pressure flows of Newtonian fluids, more recently developed, numerical methods seek to deepen the understanding of more realistic flow situations that include shear-thinning and non-isothermal effects. With the advent of more powerful computers, considerable progress has been made in the modeling and simulation of polymer melt flows in single-screw extruders. This work reviews the historical developments from a methodological point of view, including (1) exact analytical, (2) numerical, and (3) approximate methods. Special attention is paid to the mathematical models used in each case, including both governing flow equations and boundary conditions. In addition, the literature on leakage flow and curved-channel systems is revisited.
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Biasotto, Cleber, Viktor Gonda, Lis K. Nanver, Tom L. M. Scholtes, Johan van der Cingel, Daniel Vidal, and Vladimir Jovanović. "Low-Complexity Full-Melt Laser-Anneal Process for Fabrication of Low-Leakage Implanted Ultrashallow Junctions." Journal of Electronic Materials 40, no. 11 (September 9, 2011): 2187–96. http://dx.doi.org/10.1007/s11664-011-1734-6.
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Šadek, Siniša, Srđan Špalj, and Bruno Glaser. "Influence of Modelling Options in RELAP5/SCDAPSIM and MAAP4 Computer Codes on Core Melt Progression and Reactor Pressure Vessel Integrity." Science and Technology of Nuclear Installations 2010 (2010): 1–11. http://dx.doi.org/10.1155/2010/163279.
Повний текст джерелаАнотація:
RELAP5/SCDAPSIM and MAAP4 are two widely used severe accident computer codes for the integral analysis of the core and the reactor pressure vessel behaviour following the core degradation. The objective of the paper is the comparison of code results obtained by application of different modelling options and the evaluation of influence of thermal hydraulic behaviour of the plant on core damage progression. The analysed transient was postulated station blackout in NPP Krško with a leakage from reactor coolant pump seals. Two groups of calculations were performed where each group had a different break area and, thus, a different leakage rate. Analyses have shown that MAAP4 results were more sensitive to varying thermal hydraulic conditions in the primary system. User-defined parameters had to be carefully selected when the MAAP4 model was developed, in contrast to the RELAP5/SCDAPSIM model where those parameters did not have any significant impact on final results.
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Zainal, Nurfarina, S. J. N. Mitchell, D. W. McNeill, and W. M. Jubadi. "Development of photodiode via the rapid melt growth (RMG) materials for energy conversion device." Indonesian Journal of Electrical Engineering and Computer Science 18, no. 3 (June 1, 2020): 1188. http://dx.doi.org/10.11591/ijeecs.v18.i3.pp1188-1198.
Повний текст джерелаАнотація:
<span>Germanium (Ge) photodiodes were fabricated with the new RMG crucible materials that were established in this study. Results show that Ge large square patterns with size of 208 µm x 208 µm were unable to be achieved if ion implantation process was used in formation of photodiode. Delamination can be observed on all test samples during polycrystalline silicon (poly-Si) deposition at 620 <sup>o</sup>C. This result was in contrast to a previous intrinsic Ge test structure, where good formation of squares with size similar to that 208 µm x 208 µm had been successfully attained even with high annealing temperature above 938 <sup>o</sup>C. This indicates that doping through ion implantation has affected Ge film and caused delamination even at low temperature. However, good formations of Ge stripes were attained along with the ion implantation process in fabricating the photodiode. Results show that the sheet resistance of Ge stripe has significantly decreased compared to previous Ge resistors. The better resistance is due to the thicker (500 nm) Ge layer. In the case of Ge stripes with a p-i-n junction, only small fraction of test samples have shown a diode characteristic but with high leakage current. Results of I-V measurement show that a large fraction of test samples produced resistor characteristics. The high leakage current is believed due to the fact that the Ge films formed at this stage were polycrystalline in structure. Thus the grain size of Ge stripe has affected the performance. Slight changes on the I-V characteristic of single Ge can be observed when samples were tested under illumination. Therefore, it has potential to be used for future development of energy conversion device. </span>
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Shin, Woo, Suk Ko, Hyung Song, Young Ju, Hye Hwang, and Gi Kang. "Origin of Bypass Diode Fault in c-Si Photovoltaic Modules: Leakage Current under High Surrounding Temperature." Energies 11, no. 9 (September 12, 2018): 2416. http://dx.doi.org/10.3390/en11092416.
Повний текст джерелаАнотація:
Bypass diodes have been widely utilized in crystalline silicon (c-Si) photovoltaic (PV) modules to maximize the output of a PV module array under partially shaded conditions. A Schottky diode is used as the bypass diode in c-Si PV modules due to its low operating voltage. In this work, we systematically investigated the origin of bypass diode faults in c-Si PV modules operated outdoors. The temperature of the inner junction box where the bypass diode is installed increases as the ambient temperature increases. Its temperature rises to over 70 °C on sunny days in summer. As the temperature of the junction box increases from 25 to 70 °C, the leakage current increases up to 35 times under a reverse voltage of 15 V. As a result of the high leakage current of the bypass diode at high temperature, melt down of the junction barrier between the metal and semiconductor has been observed in damaged diodes collected from abnormally functioning PV modules. Thus, it is believed that the constant leakage current applied to the junction caused the melting of the junction, thereby resulting in a failure of both the bypass diode and the c-Si PV module.
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Mahroug, Imane, Stefania Doppiu, Jean-Luc Dauvergne, Angel Serrano, and Elena Palomo del Barrio. "Li4(OH)3Br-Based Shape Stabilized Composites for High-Temperature TES Applications: Selection of the Most Convenient Supporting Material." Nanomaterials 11, no. 5 (May 13, 2021): 1279. http://dx.doi.org/10.3390/nano11051279.
Повний текст джерелаАнотація:
Peritectic compound Li4(OH)3Br has been recently proposed as phase change material (PCM) for thermal energy storage (TES) applications at approx. 300 °C Compared to competitor PCM materials (e.g., sodium nitrate), the main assets of this compound are high volumetric latent heat storage capacity (>140 kWh/m3) and very low volume changes (<3%) during peritectic reaction and melting. The objective of the present work was to find proper supporting materials able to shape stabilize Li4(OH)3Br during the formation of the melt and after its complete melting, avoiding any leakage and thus obtaining a composite apparently always in the solid state during the charge and discharge of the TES material. Micro-nanoparticles of MgO, Fe2O3, CuO, SiO2 and Al2O3 have been considered as candidate supporting materials combined with the cold-compression route for shape-stabilized composites preparation. The work carried out allowed for the identification of the most promising composite based on MgO nanoparticles through a deep experimental analysis and characterization, including chemical compatibility tests, anti-leakage performance evaluation, structural and thermodynamic properties analysis and preliminary cycling stability study.
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Huss, Matthias, Andreas Bauder, Mauro Werder, Martin Funk, and Regine Hock. "Glacier-dammed lake outburst events of Gornersee, Switzerland." Journal of Glaciology 53, no. 181 (2007): 189–200. http://dx.doi.org/10.3189/172756507782202784.
Повний текст джерелаАнотація:
AbstractGornersee, Switzerland, is an ice-marginal lake, which drains almost every year, subglacially, within a few days. We present an analysis of the lake outburst events between 1950 and 2005, as well as results of detailed field investigations related to the lake drainage in 2004 and 2005. The latter include measurements of lake geometry, water pressure in nearby boreholes and glacier surface motion. A distributed temperature-index melt model coupled to a linear-reservoir runoff model is used to calculate hourly discharge from the catchment of Gornergletscher in order to distinguish between the melt/precipitation component and the outburst component of the discharge hydrograph. In this way, drainage volume and timing are determined. From 1950 there is a clear trend for the outburst flood to occur earlier in the melt season, but there is no trend in lake discharge volumes. Peak discharges from the lake lie significantly below the values obtained using the empirical relation proposed by Clague and Mathews (1973). The shapes of the 2004 and 2005 lake outflow hydrographs differ substantially, suggesting different drainage mechanisms. From water balance considerations we infer a leakage of the glacier-dammed lake in 2005, starting 1 week prior to the lake outburst. During the drainage events, up to half of the lake water is temporarily stored in the glacial system, causing substantial uplift of the glacier surface.
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Park, Sang-Hyun, Kwang-Hyun Bang, and Jong-Rae Cho. "Structural Integrity Evaluation of a Reactor Cavity during a Steam Explosion for External Reactor Vessel Cooling." Energies 14, no. 12 (June 17, 2021): 3605. http://dx.doi.org/10.3390/en14123605.
Повний текст джерелаАнотація:
Nuclear power is a major source of electricity in the international community. However, a significant problem with nuclear power is that, if a severe nuclear accident occurs, radiation may leak and cause great damage. As such, research on nuclear safety has become increasingly popular worldwide. In this paper, the structural integrity of a reactor cavity during a steam explosion—one kind of the aforementioned severe nuclear accidents—was evaluated. Steam explosions are primarily caused by fuel–coolant interactions (FCI), and result from issues in the cooling system that discharges the melt from the reactor core to the outside. A steam explosion can damage the nuclear power plant, and radiation leakage, the greatest concern, may occur. In the Chernobyl or Fukushima Daiichi accidents, significant radiation leakages resulted in damages extending beyond the country of origin. In this paper, a steam explosion was simulated using values given by the transient analysis code for explosive reactions (TRACER-II)—the only steam explosion code in Korea. The walls of the reactor cavity were modeled after the APR-1400 currently operating in Korea. The integrity of the concrete, rebars, and liner plate in the reactor cavity during a steam explosion was evaluated in terms of stress and ductile failure strain limits.
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Nazir, Muhammad Tariq, Faizan Tahir Butt, Bao Toan Phung, Guan Heng Yeoh, Ghulam Yasin, Shakeel Akram, Muhammad Shoaib Bhutta, Shahid Hussain, and Tuan Anh Nguyen. "Simulation and Experimental Investigation on Carbonized Tracking Failure of EPDM/BN-Based Electrical Insulation." Polymers 12, no. 3 (March 5, 2020): 582. http://dx.doi.org/10.3390/polym12030582.
Повний текст джерелаАнотація:
Ethylene propylene diene monomer (EPDM) is broadly employed as an insulating material for high voltage applications. Surface discharge-induced thermal depolymerization and carbon tracking adversely affect its performance. This work reports the electrical field modeling, carbon tracking lifetime, infrared thermal distribution, and leakage current development on EPDM-based insulation with the addition of nano-BN (boron nitride) contents. Melt mixing and compression molding techniques were used for the fabrication of nanocomposites. An electrical tracking resistance test was carried out as per IEC-60587. Simulation results show that contamination significantly distorted the electrical field distribution and induced dry band arcing. Experimental results indicate that electric field stress was noticed significantly higher at the intersection of insulation and edges of the area of contamination. Moreover, the field substantially intensified with the increasing voltage levels. Experimental results show improved carbonized tracking lifetime with the addition of nano-BN contents. Furthermore, surface temperature was reduced in the critical contamination flow path. The third harmonic component in the leakage current declined with the increase of the nano-BN contents. It is concluded that addition of nano-BN imparts a better tracking failure time, and this is attributed to better thermal conductivity and thermal stability, as well as an improved shielding effect to electrical discharges on the surface of nanocomposite insulators.
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Kurina, I., M. Frolova, E. Chesnokov, and O. Plaksin. "POSSIBILITY OF APPLICATION OF ZrO2-MgO-CaO CRUCIBLES FOR PRODUCING ALLOY U-10 % Zr." PROBLEMS OF ATOMIC SCIENCE AND TECHNOLOGY. SERIES: NUCLEAR AND REACTOR CONSTANTS 2021, no. 4 (December 26, 2021): 28–34. http://dx.doi.org/10.55176/2414-1038-2021-4-28-34.
Повний текст джерелаАнотація:
It is known that the thermal shock resistance of ceramic crucibles is insufficient for melting uranium alloys in them. Typically, crucibles withstand one or more heats and then break down. The possibility of using nanostructured ceramic crucibles based on ZrO2-MgO-CaO to obtain a U-10 % Zr alloy in an induction electric furnace has been substantiated at IPPE. Crucibles were made in JSC “ONPP “Tekhnologiya” named after A.G. Romashin” from a mixture of zirconium dioxide powders, partially stabilized with nanocrystalline CaO and MgO in a ratio of 30 and 70 wt. %, using two-stage sintering. Such crucibles have a sufficiently high resistance to thermal shock in contact with melts of metals and alloys and withstand 1-3 melts without destruction. Crucibles with various densities (from 5.206 to 5.29 g/cm3) and porosity (from 5 to 9 %) were tested under conditions of heating the melt at a rate of 12 to 19 °C/min to a maximum temperature of 1455 to 1560 °C. The tested crucible ZrO2-MgO-CaO was inserted into a graphite crucible to prevent leakage of the melt in the electric furnace in case of destruction of the ceramic crucible. There was no complete destruction of the crucibles; some crucibles with small cracks could be reused. The best result (three melts) was obtained when using such a crucible with a porosity of about 5 % for melting a charge containing uranium and zirconium. In order to determine the degree of interaction of a uranium-zirconium melt with a crucible based on ZrO2-MgO-CaO, the microstructure and microhardness of the crucible surface in contact with the melt were studied at an elevated temperature of 1600 °C. The surface of all tested crucibles is not wetted by liquid uranium-zirconium melt, and there is no chemical interaction. Nanostructured ceramic crucibles based on ZrO2-MgO-CaO are suitable for melting uranium-containing materials in an electric induction furnace.
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Park, Simon S., Chul B. Park, Dmitry Ladin, Hani E. Naguib, and Costas Tzoganakis. "Development of a Dilatometer for Measurement of the PVT Properties of a Polymer/CO2 Solution Using a Foaming Extruder and a Gear Pump." Journal of Manufacturing Science and Engineering 124, no. 1 (March 1, 2001): 86–91. http://dx.doi.org/10.1115/1.1418696.
Повний текст джерелаАнотація:
This paper presents an innovative dilatometer that can measure the pressure-volume-temperature (PVT) properties of polymer/CO2 solutions in a molten state. The basic rationale of the design is to determine the density (or equivalently, the specific volume) of a polymer/CO2 solution by separately measuring the mass and volume flow rates of the solution flowing in an extruder at each temperature and pressure. A positive-displacement gear pump mounted on an extruder is used to measure the volume flow rate of the solution. A single-phase polymer/CO2 solution is formed by injecting a metered amount of CO2 into a polymer melt and completely dissolving it in the melt using a foam extrusion line. The temperature of solution was precisely controlled and homogenized by using the second extruder in a tandem system and a heat exchanger with a static mixer. The pressure was controlled by the rotational speed of the screw in the second extruder. In order to reduce leakage across the gear pump, the difference between the upstream and downstream pressures was minimized using a variable resistance valve attached downstream of the gear pump. The mass flow rate was measured by directly collecting the extruded polymer melt for a fixed time after degassing CO2. A critical set of experiments was carried out to verify the functions of the system using pure polymer melts with known PVT data. Finally, the system was used to measure the specific volume of PS/CO2 solutions as a function of CO2 concentration, temperature, and pressure.
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Cherkesov, Zaur A. "SYNTHESIS OF HIGHLY DISPERSED MOLYBDATE OF COBALT IN THE MELT SYSTEM (Na2MoO4 - NaCl)EVT – CoSO4." IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENII KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA 63, no. 9 (August 5, 2020): 70–76. http://dx.doi.org/10.6060/ivkkt.20206309.6205.
Повний текст джерелаАнотація:
The paper presents a new computational and experimental material for the development of a rational method for obtaining one of the significant representatives of the elements of the d-family-cobalt molybdate in melts of the system (Na2MoO4 - NaCl)evt-CoSO4 in a highly dispersed state at a relatively low temperature and high process performance. It contains extensive material on the properties and applications of cobalt molybdenum, a critical analysis of which indicates the need to develop new approaches to the synthesis of such a unique compound. Along with experimental problems, the article also solves a number of theoretical issues. In particular, we are talking about the application of the mass transfer effect between Mn(Fe,Co)MoO4 – Na2CO3 systems and the environment for the first time revealed by the authors to the analysis of the drug CoMoO4 synthesized in the work. The mechanism of manifestation of this phenomenon, which, as shown by theoretical analysis and experimental data, due to polyvalences cobalt. Therefore, this is due to the possibility of leakage in the system CoMoO4–Na2CO3 exchange reaction CoMoO4+Na2CO3→CoCO3+Na2MoO4, dissociation CoCO3=CoO+CO2 and redox of хCoO+1/2О2→CoхOу, where y=x+1, leading to the loss of CO2 and the transformation of CoO – product of the decomposition of CoCO3 at the expense of the oxygen environment to the oxide type CoхOу, the composition of which is determined by the process temperature. The experimental data obtained in this work confirm the effectiveness of the mass transfer effect in the analysis of molybdenum and tungstates of polyvalent d-elements. Much attention is paid to the comprehensive study of the obtained cobalt molybdate in the system (Na2MoO4 - NaCl)evt–CoSO4 by a complex of physical and chemical methods (thermodynamic, x-ray phase, dispersion, chemical kinetic (thermogravimetric)).
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Leng, Bin Bin, Mei Zhu Chen, Shao Ping Zheng, and Shao Peng Wu. "Theoretical and Experimental Studies on Preparation of OMMT-Based Composite Phase Change Materials Used in Asphalt Pavement." Key Engineering Materials 599 (February 2014): 355–60. http://dx.doi.org/10.4028/www.scientific.net/kem.599.355.
Повний текст джерелаАнотація:
With the global warming, phase change materials are being expected to be applied in asphalt pavement to help lower its surface temperature. In this study, a kind of composite phase change material was prepared and its technique parameters were optimized through theoretical analysis and experimental study. A solid-liquid phase change material, with melt point of 43°C and phase transition heat of 161.6J/g, was used as core. The organophilic montmorillonite (OMMT) was used as a carrier and can prevent leakage of the melted phase change materials. The results showed that the ratio of OMMT to lauric acid was 2.6:1, and the melting temperature and time were 74°Cand 1.5hours, respectively. The composite phase change material prepared in this study had the phase transition latent heat of 36.168J/g and the transition temperature of 40.094°C. And the experimental results are in good agreement with theoretical analysis.
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Gao, Zeng, Xianli Ba, Huanyu Yang, Congxin Yin, Shanguang Liu, Jitai Niu, and Josip Brnic. "Joining of Silicon Particle-Reinforced Aluminum Matrix Composites to Kovar Alloys Using Active Melt-Spun Ribbons in Vacuum Conditions." Materials 13, no. 13 (July 2, 2020): 2965. http://dx.doi.org/10.3390/ma13132965.
Повний текст джерелаАнотація:
The vacuum brazing of dissimilar electronic packaging materials has been investigated. In this research, this applies silicon particle-reinforced aluminum matrix composites (Sip/Al MMCs) to Kovar alloys. Active melt-spun ribbons were employed as brazing filler metals under different joining temperatures and times. The results showed that the maximum joint shear strength of 96.62 MPa was achieved when the joint was made using Al-7.5Si-23.0Cu-2.0Ni-1.0Ti as the brazing filler metal at 580 °C for 30 min. X-ray diffraction (XRD) analysis of the joint indicated that the main phases were composed of Al, Si and intermetallics, including CuAl, TiFeSi, TiNiSi and Al3Ti. When the brazing temperature ranged from 570 °C to 590 °C, the leakage rate of joints remained at 10−8 Pa·m3/s or better. When the joint was made using Al-7.5Si-23.0Cu-2.0Ni-2.5Ti as the brazing filler metal at 580 °C for 30 min, the higher level of Ti content in the brazing filler metal resulted in the formation of a flake-like Ti(AlSi)3 intermetallic phase with an average size of 7 µm at the interface between the brazing seam and Sip/Al MMCs. The joint fracture was generally in the form of quasi-cleavage fracture, which primarily occurred at the interface between the filler metal and the Sip/Al MMCs. The micro-crack propagated not only Ti(AlSi)3, but also the Si particles in the substrate.
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Liu, Peng, Xiaobin Gu, Zhikai Zhang, Jianping Shi, Jun Rao, and Liang Bian. "Fabrication and Thermal Properties of Capric Acid/Calcinated Iron Tailings/Carbon Nanotubes Composite as Form-Stable Phase Change Materials for Thermal Energy Storage." Minerals 9, no. 11 (October 23, 2019): 648. http://dx.doi.org/10.3390/min9110648.
Повний текст джерелаАнотація:
In this study, a novel form-stable phase change material (FSPCM) consisting of calcination iron tailings (CIT), capric acid (CA), and carbon nanotubes (CNT) was prepared using a simple direct melt impregnation method, and a series of tests have been carried out to investigate its properties. The leakage tests showed that CA can be retained in CIT with a mass fraction of about 20 wt.% without liquid leakage during the phase change process. Moreover, the morphology, chemical structure, and thermal properties of the fabricated composite samples were investigated. Scanning electron microscope (SEM) micrographs confirmed that CIT had a certain porous structure to confine CA in composites. According to the Fourier transformation infrared spectroscope (FTIR) results, the CA/CIT/CNT FSPCM had good chemical compatibility. The melting temperature and latent heat of CA/CIT/CNT by differential scanning calorimeter (DSC) were determined as 29.70 °C and 22.69 J/g, respectively, in which the mass fraction of CIT and CNT was about 80 wt.% and 5 wt.%, respectively. The thermal gravity analysis (TGA) revealed that the CA/CIT/CNT FSPCM showed excellent thermal stability above its working temperature. Furthermore, the melting and freezing time of CA/CIT/CNT FSPCM doped with 5 wt.% CNT reduced by 42.86% and 54.55% than those of pure CA, and it showed better heat transfer efficiency. Therefore, based on the above analyses, the prepared CA/CIT/CNT FSPCM is not only a promising candidate material for the application of thermal energy storage in buildings, but it also provides a new approach for recycling utilization of iron tailings.
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Ou, Hsien-Wang. "Watermass Properties of the Antarctic Slope Front: A Simple Model*." Journal of Physical Oceanography 37, no. 1 (January 1, 2007): 50–59. http://dx.doi.org/10.1175/jpo2981.1.
Повний текст джерелаАнотація:
Abstract In the Antarctic, dense shelf water is formed in coastal polynyas and is differentiated from the fresher surface water by the wind-induced ice motion that displaces offshore the ice melt from production zones. Where the shelf water discharges into the deep ocean, the Antarctic Slope Front (ASF) is V shaped, separating the shelf and surface waters (referred to as “frontal” waters) from the Circumpolar Deep Water (CDW). To elucidate basic constraints on frontal properties, a minimal model of homogeneous water masses forced by offshore wind and freshwater input in a perpetual winter is considered. With the surface water stirred by—and hence aligned with—the ice cover, there is little leakage of ice or meltwater from the frontal system, so ice production and melt merely redistribute heat and salt between frontal waters. As such, the heat loss to the atmosphere needs to be supplied by entraining CDW, which then necessitates the shelf water discharge on account of the mass balance. Because of the freshwater input, the discharged shelf water may not be saltier than the CDW, which thus may descend the slope to form bottom water only because of its coldness. With both frontal waters cooled to the freezing point, dominant balances are formulated to determine their salinity and exchange rate with the ambient CDW. Although extremely crude, the model derivations are favorably compared with observations, which thus may provide physically based parameterizations for the bottom-water formation that can be incorporated into global models.
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Zhang, Shi Chao, Guang Hai Wang, Wei Wu, Yu Feng Chen, and Hao Ran Sun. "Study on Properties and Application of PG/CS Composite PCMs." Key Engineering Materials 602-603 (March 2014): 624–27. http://dx.doi.org/10.4028/www.scientific.net/kem.602-603.624.
Повний текст джерелаАнотація:
Tris (hydroxymethyl) ethane (PG) as a phase change material, micro-porous xonotlite (CS) as matrix, PG/CS composite PCMs were prepared by melt-soaking method, and the effect of micro-porous structure of xonotlite on heat absorption capacity, bending strength and insulation performance of composites, and the exudation of PG was studied. Otherwise, for the work environment and characteristics of propulsive device of vehicle, this paper explored the feasibility that phase change materials (PCMs) worked as the insulation material in short-time insulation system of the vehicle. Experimental results show that, when the most probable pore diameters of xonotlite was not less than 63nm, the composites presented better and almost same absorption capacities of matrix (CS) to PCM (PG) in different composites; when up to 85nm, the composite exhibited the lowest leakage rate (less than 5%), the optimal mechanical property and thermal insulation performance. This Study proposed a new idea for the design of the insulation material in the thermal protection system of propulsive device of vehicle.
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Qiu, Zhongyong, and Chunju He. "Polypropylene Hollow Fiber Membrane by Dissolution-Inducing Pore Methods." Membranes 12, no. 5 (April 25, 2022): 463. http://dx.doi.org/10.3390/membranes12050463.
Повний текст джерелаАнотація:
Plasma leakage limits the development of polypropylene membranes as oxygenated membranes. Here, a new method named the dissolution-induced pore method was adapted to prepare polypropylene hollow fiber membranes: after polypropylene and polyvinyl chloride were melt-blended and extruded, the polyvinyl chloride was removed by N, N-dimethylacetamide to obtain a porous polypropylene membrane material. The variation of membranes has been explored in detail with respect to the influence of different parameters on the flux and mechanical properties of membranes and the feasibility of the polyvinyl chloride recovery. The resulting polypropylene hollow fiber membrane shows that plasma penetration was zero within 6 h of test, gas flux can reach 189,000 L/(m2·h·0.1 MPa), and its strength at break reaches 65 MPa and the elongation at break is 890%; polyvinyl chloride recovery achieves more than 99%. This research has developed a promising and low-cost extracorporeal membrane oxygenation material, which provides benefits for patients with less capacity for medical expenditure.
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Qiu, Zhongyong, and Chunju He. "Polypropylene Hollow Fiber Membrane by Dissolution-Inducing Pore Methods." Membranes 12, no. 5 (April 25, 2022): 463. http://dx.doi.org/10.3390/membranes12050463.
Повний текст джерелаАнотація:
Plasma leakage limits the development of polypropylene membranes as oxygenated membranes. Here, a new method named the dissolution-induced pore method was adapted to prepare polypropylene hollow fiber membranes: after polypropylene and polyvinyl chloride were melt-blended and extruded, the polyvinyl chloride was removed by N, N-dimethylacetamide to obtain a porous polypropylene membrane material. The variation of membranes has been explored in detail with respect to the influence of different parameters on the flux and mechanical properties of membranes and the feasibility of the polyvinyl chloride recovery. The resulting polypropylene hollow fiber membrane shows that plasma penetration was zero within 6 h of test, gas flux can reach 189,000 L/(m2·h·0.1 MPa), and its strength at break reaches 65 MPa and the elongation at break is 890%; polyvinyl chloride recovery achieves more than 99%. This research has developed a promising and low-cost extracorporeal membrane oxygenation material, which provides benefits for patients with less capacity for medical expenditure.
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Hartl, F., H. Luyten, H. A. Nieuwenhuis, and G. C. Schoemaker. "Versatile Cryostated Optically Transparent Thin-Layer Electrochemical (OTTLE) Cell for Variable-Temperature UV-Vis/IR Spectroelectrochemical Studies." Applied Spectroscopy 48, no. 12 (December 1994): 1522–28. http://dx.doi.org/10.1366/0003702944027787.
Повний текст джерелаАнотація:
This article describes the construction of a novel optically transparent thin-layer electrochemical (OTTLE) cell for IR and UV-Vis spectroelectrochemical experiments at variable temperature. The cell has a three-electrode set melt-sealed into a smooth polyethylene spacer which is sandwiched between two CaF2 windows. The width of this spacer (0.18–0.20 mm) defines the thickness of the thin solution layer. The whole electrode assembly is housed in a thermostated Cu block of the OTTLE cell which fits into a double-walled nitrogen-bath cryostat. The experimental setup permits relatively fast electrolysis within the tested temperature range of 295 to 173 K under strictly anaerobic conditions and protection of light-sensitive compounds. Other important merits of the cell design include lack of leakage, facile cleaning, almost negligible variation of the preset temperature, and facile manipulation in the course of the experiments. The applicability of the variable-temperature IR/UV-Vis OTTLE cell is demonstrated by stabilization of a few electrogenerated carbonyl complexes of Mn(I) and Ru(II) with 3,5-di- tert. butyl-1,2-benzo(semi)quinone (DB(S)Q) and N, N′-diisopropyl-1,4-diaza-1,3-butadiene (iPr-DAB) ligands, respectively, at appropriately low temperatures.
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Marsh, Bruce D. "Solidification fronts and magmatic evolution." Mineralogical Magazine 60, no. 398 (February 1996): 5–40. http://dx.doi.org/10.1180/minmag.1996.060.398.03.
Повний текст джерелаАнотація:
AbstractFrom G. F. Becker's and L. V. Pirsson's early enunciations linking the dynamics of magma chambers to the rock records of sills and plutons to this day, two features stand at the centre of nearly every magmatic process: solidification fronts and phenocrysts. The structure and behaviour of the envisioned solidification front, however, has been mostly that akin to non-silicate, non-multiply-saturated systems, which has led to confusion in appreciating its role in magmatic evolution. The common habit of intruding magmas to carry significant amounts of phenocrysts, which can lead to efficient fractionation, layering, and interstitial melt flow within extensive mush piles, when coupled with solidification fronts, allows a broad understanding of the processes leading to the rock records of sills and lava lakes. These same processes are fundamental to understanding all magmas.The spatial manifestation of the liquidus and solidus is the Solidification Front (SF); all magmas, stationary or in transit, are encased by SFs. In the ideal case of an initially crystal-free, cooling magma, crystallinity increases from nucleation on the leading liquidus edge to a holocrystalline rock at the trailing solidus. The package of SF isotherms advances inward, thickening with time and, depending on location — roof, floor, or walls — and the initial crystallinity of the magma, is instrumental in controlling magmatic evolution. Bimodal volcanism as well as much of the structure of the oceanic crust may arise from the behaviour of SFs.In mafic magmas, somewhere near a crystallinity (N) of 55% (vol), depending on the phase assemblage, the SF changes from a viscous fluid (suspension (0<N<25) and mush (25<N<55%)) to an elastic crystalline network (rigid crust (55<N<100%)) of some strength containing interstitial residual melt. With thickening of the roofward SF of some mafic magmas, the weight of the leading, viscous portion repeatedly tears the crust near N ∼ 55–60%, efficiently segregating the local residual melt into zones of interdigitating silicic lenses. This is SF instability (SFI), a process of possible importance in continental crust initiation and evolution, in producing silicic segregations in oceanic crust, and in recording the inability of the viscous part of the upper SF ever to detach wholly in typical (<∼ 1 km) sheet-like magmas. These granophyric and pegmatitic segregations, individually reaching 1–2 m in thickness and 30–50 m in length, form thick (∼ 50–75 m) zones that can be misconstrued as sandwich horizons where the last liquids might have accumulated. In effectively splitting the magma chemically and spatially, SFI is, in essence, a form of chaos (i.e. silicic chaos).Differentiation of initially crystal-free, stationary magmas is limited to processes occurring within SFs, which operate in competition with the rate of inward advancement of solidification. Local processes operating on characteristic time scales longer than the time for the SF to advance a distance equal to its own thickness are suppressed. Enormous increases in viscosity outward within the viscous, leading portion of the SF efficiently partition the distribution of melt accessible to eruption. Eruptible melts lie essentially inward of the SF and are thus severely restricted in silica enrichment. The silica-enriched SFI melts are thus generally inaccessible to collection and eviction unless the host SF is reprocessed or “burned back” through, respectively, later regional magmatism or massive, late-stage re-injection. And because of large viscosity contrasts between SFI melts and host basalts, once freed, SFI melts are literally impossible to homogenize back into the system and may collect and compact against the roof to form large silicic masses. Unusually voluminous, bulbous masses of silicic granophyre present along, and sometimes warping, the roofs of large diabase sills may reflect collections of remobilized blobs of SFI melts. These bulbous masses may be later added to the continental crust through solid state creep.In sheets made of phenocryst-rich, singly saturated magma, most phenocrysts are able through settling or floating to avoid capture by the advancing SFs. Significant differentiation is possible through extensive settling of initial phenocrysts and upward leakage of interstitial residual melt from the associated cumulate pile, which over-thickens the lower SF, greatly tipping the competitive edge against suppression of melt leakage by advancing solidification. Dense interstitial melts may similarly drain from roofward cumulates of light phenocrysts. The variation in crystal size and modal abundance in these cumulate piles are intimate records of prior crystallization, transport, and filling.Magmas in transit erode SFs and thoroughly charge the magma with crystals, facilitating fractionation and differentiation, especially if the body occasionally comes to rest. The key to protracted differentiation through fractional crystallization is not crystallization in stationary, closed chambers, but the repeated transport and chambering of magma or the periodic resupply to chambers of phenocryst-rich magma. This is punctuated differentiation, which may be the general case. Close corollaries are that thick, closed sheets of initially crystal-free, multiply-saturated magma undergo precious little overall differentiation, and that deciphering the sequence and crystallinity, including in transit phenocryst entrainment, growth, and sorting, of the filling events is central to unravelling intrusive history.Variations in temperature, whether on phase diagrams or in actual magmas, are intrinsically linked to commensurate variations in space and time in magmatic systems. The spectrum of all physical and chemical processes associated with magma is accordingly strongly partitioned in space and time.The idea of a magma chamber as a vat of low crystallinity melt crystallizing everywhere within and differentiating through crystal settling is unrealistic. A magma chamber formed of any number of crystal-laden inputs, encased by inward-propagating, dynamic solidification fronts, and where significant differentiation is tied to the dynamics of late-stage, interstitial melt within extensive mush piles is more in accord with the rock record.
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Erofeeva, N. V., V. I. Korchagin, and A. V. Protasov. "Synthesis of Pro-oxidants based on waste oil and fat production." Proceedings of the Voronezh State University of Engineering Technologies 80, no. 3 (December 17, 2018): 362–67. http://dx.doi.org/10.20914/2310-1202-2018-3-362-367.
Повний текст джерелаАнотація:
The use of a mixture of fatty acids (LC) without separation in the synthesis of Pro-oxidants (PO), which are salts of metals of variable valence, allows for the effective utilization of waste from the stage of refining vegetable oils. The use of the LC mixture in the synthesis of SOFTWARE is justified by the similarity of the IR spectra of the mixture of LC and stearic acid (SC). SOFTWARE synthesis was carried out by a method including saponification of the mixture with sodium compounds, followed by interaction with compounds of two and trivalent iron. The use of ultrasound exposure to high-intensity 150?200 W/dm3 in the synthesis in the melt promotes the intensification of the process and ensures the implementation stage of the saponification at a temperature of 150?170 OC, and the stage of synthesis at a temperature of about 110 OS with the release of more than 99,0% of the mass. with a total duration less than 20 min. Using highly efficient ultrasonic treatment during the synthesis of QOL reduces emissions of polluting substances (pollutants) into the atmosphere through leakage of the reactor, because in the synthesis of iron stearate (FW) observed decrease in emissions of SV into the atmosphere more than 13 times, and in the synthesis of QL only 5.5 times, due to the presence of low-boiling LC, including unsaturated in the mixture.
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Luthcke, Scott B., Anthony A. Arendt, David D. Rowlands, John J. McCarthy, and Christopher F. Larsen. "Recent glacier mass changes in the Gulf of Alaska region from GRACE mascon solutions." Journal of Glaciology 54, no. 188 (2008): 767–77. http://dx.doi.org/10.3189/002214308787779933.
Повний текст джерелаАнотація:
AbstractThe mass changes of the Gulf of Alaska (GoA) glaciers are computed from the Gravity Recovery and Climate Experiment (GRACE) inter-satellite range-rate data for the period April 2003–September 2007. Through the application of unique processing techniques and a surface mass concentration (mascon) parameterization, the mass variations in the GoA glacier regions have been estimated at high temporal (10 day) and spatial (2 × 2 arc-degrees) resolution. The mascon solutions are directly estimated from a reduction of the GRACE K-band inter-satellite range-rate data and, unlike previous GRACE solutions for the GoA glaciers, do not exhibit contamination by leakage from mass change occurring outside the region of interest. The mascon solutions reveal considerable temporal and spatial variation within the GoA glacier region, with the largest negative mass balances observed in the St Elias Mountains including the Yakutat and Glacier Bay regions. The most rapid losses occurred during the 2004 melt season due to record temperatures in Alaska during that year. The total mass balance of the GoA glacier region was −84 ± 5 Gt a−1 contributing 0.23 ± 0.01 mm a−1 to global sea-level rise from April 2003 through March 2007. Highlighting the large seasonal and interannual variability of the GoA glaciers, the rate determined over the period April 2003–March 2006 is −102 ± 5 Gt a−1, which includes the anomalously high temperatures of 2004 and does not include the large 2007 winter balance-year snowfall. The mascon solutions agree well with regional patterns of glacier mass loss determined from aircraft altimetry and in situ measurements.
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Liang, Xiao Ping, Lei Xiao, Sang Sang Liao, and Bin Jiang. "Temperature Field and Cast-Rolling Force Prediction during Horizontal Twin-Roll Casting Magnesium Alloy." Materials Science Forum 747-748 (February 2013): 412–20. http://dx.doi.org/10.4028/www.scientific.net/msf.747-748.412.
Повний текст джерелаАнотація:
The control of process parameters in the horizontal twin-roll casting is crucial for the quality of sheet and the continuity of the process. A temperature field coupled with flow field mathematical model was established during the horizontal twin-roll casting of AZ31 magnesium alloy sheet with 1500mm in width and 8mm in thickness in this paper. The temperature field in the casting zone was solved by the software ANSYS. The effect of process factors, such as casting speed, pouring temperature and cooling intensity, on casting zone temperature of different process parameters were studied. Based on the solved temperature field, with the hot roll formula and test data of yield strength, the effect of casting speed, pouring temperature and cooling intensity on cast-rolling force in the cast-rolling zone was also dicussed. The results indicate that the casting speed has the greatest effect upon the temperature field and cast-rolling force, while the pouring temperature is the least. In addition, the value of critical cooling intensity increased with the increase of the casting speed. The quality defect called melt sheet or the leakage phenomenon appear when the cooling intensity is lower than the minimal critical cooling intensity value, and crack or rolling suspended appear if the cooling intensity is higher than the maximal critical cooling intensity value. When the casting speed are 1m/min, 2m/min and 3m/min, the minimal and maximal critical cooling intensity are 500, 1200, 2 000 W/(m2.K) and 2500, 5000, 7500 W/(m2.K) respectively.
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Hallik, Jaanus, and Targo Kalamees. "Development of Airtightness of Estonian Wooden Buildings." Journal of Sustainable Architecture and Civil Engineering 24, no. 1 (April 17, 2019): 36–43. http://dx.doi.org/10.5755/j01.sace.24.1.23231.
Повний текст джерелаАнотація:
The field measurements of airtightness in Estonian detached and apartment buildings conducted between2003 – 2017 were combined into a large dataset for further analysis. The buildings were classified basedon building structure, number of storeys, year of construction, energy classification and compactnessfactors. A subset with all wooden buildings (313 in total) was statistically analysed to determine theaverage (median) air leakage rates at 50 Pa and tested (Kruskal-Wallis test with post-hoc Conovertest) for significant differences within the grouping factors. As expected, the median air leakage (q50)of older buildings between 10.7 and 13.9 m3/(hm2) has decreased to 1.1 m3/(hm2) after the minimumrequirements for energy efficiency have taken effect. A more detailed analysis on newer buildings showedthat quality of the workmanship combining systematic measurement routines as well as prefabrication,yields significantly lower median air leakages compared to on-site construction. The buildings with betterenergy classification targets also achieved lower median air leakages compared to buildings designedto meet minimum requirements. Further analysis showed significant differences between buildingswith lightweight timber construction and those with log construction. This can be due to fact that theairtightness has been predominantly measured in prefabricated buildings compared to on-site buildingtechnology. Surprisingly, the analysis showed no significant difference between buildings with a differentcompactness factor or a different number of storeys. For use in energy calculations, the base values ofair leakage rates for each group are calculated and presented accounting for variation of measurements.
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HURME, EERO U., GUN WIRTANEN, LENA AXELSON-LARSSON, NUNO A. M. PACHERO, and RAIJA AHVENAINEN. "Penetration of Bacteria through Microholes in Semirigid Aseptic and Retort Packages." Journal of Food Protection 60, no. 5 (May 1, 1997): 520–24. http://dx.doi.org/10.4315/0362-028x-60.5.520.
Повний текст джерелаАнотація:
The penetration of vegetative cells of Enterobacter aerogenes, Bacillus subtilis, Micrococcus varians, and Leuconostoc mesenteraides through laser-drilled holes of diameter 10 to 20 μm in the lid of commercially manufactured semirigid aseptic cups filled with milk chocolate pudding and retort trays filled with spaghetti in meat sauce (only E. aerogenes) was studied. The ability of bacteria to pass via leakages was determined using an immersion biotest method. The threshold leakage diameter determined for both products tested was about 10 μm. The contamination rate of leaking packages was much higher for aseptic cups than retort trays. The results indicated that the factors increasing the rate of bacterial penetration into test packages are large hole size, small hole length, small bacteria diameter and leakage channels filled with liquid instead of dried foodstuff and/or bacterial suspension. The results are useful as a guideline for the requirements of on-line, nondestructive, package-integrity testers for testing packages.
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Peirce, C., I. Grevemeyer, N. W. Hayman, and H. J. A. Van Avendonk. "Active ocean–continent transform margins: seismic investigation of the Cayman Trough-Swan Island ridge-transform intersection." Geophysical Journal International 229, no. 3 (January 18, 2022): 1604–27. http://dx.doi.org/10.1093/gji/ggac019.
Повний текст джерелаАнотація:
SUMMARY The southern boundary of the Cayman Trough in the Caribbean is marked by the Swan Islands transform fault (SITF), which also represents the ocean–continent transition of the Honduras continental margin. This is one of the few places globally where a transform continental margin is currently active. The CAYSEIS experiment acquired an ∼165-km-long seismic refraction and gravity profile (P01) running across this transform margin, and along the ridge-axis of the Mid-Cayman Spreading Centre (MCSC) to the north. This profile reveals not only the crustal structure of an actively evolving transform continental margin, that juxtaposes Mesozoic-age continental crust to the south against zero-age ultraslow spread oceanic crust to the north, but also the nature of the crust and uppermost mantle beneath the ridge-transform intersection (RTI). The traveltimes of arrivals recorded by ocean-bottom seismographs (OBSs) deployed along-profile have been inverse and forward modelled, in combination with gravity modelling, to reveal an ∼25-km-thick continental crust that has been continuously thinned over a distance of ∼65 km to ∼10 km adjacent to the SITF, where it is juxtaposed against ∼3–4-km-thick oceanic crust. This thinning is primarily accommodated within the lower crust. Since Moho reflections are only sparsely observed, and, even then, only by a few OBSs located on the continental margin, the 7.5 km s–1 velocity contour is used as a proxy to locate the crust–mantle boundary along-profile. Along the MCSC, the crust–mantle boundary appears to be a transition zone, at least at the seismic wavelengths used for CAYSEIS data acquisition. Although the traveltime inversion only directly constrains the upper crust at the SITF, gravity modelling suggests that it is underlain by a higher density (>3000 kg m–3) region spanning the width (∼15 km) of its bathymetric expression, that may reflect a broad region of metasomatism, mantle hydration or melt-depleted lithospheric mantle. At the MCSC ridge-axis to the north, the oceanic crust appears to be forming in zones, where each zone is defined by the volume of its magma supply. The ridge tip adjacent to the SITF is currently in a magma rich phase of accretion. However, there is no evidence for melt leakage into the transform zone. The width and crustal structure of the SITF suggests its motion is currently predominantly orthogonal to spreading. Comparison to CAYSEIS Profile P04, located to the west and running across-margin and through 10 Ma MCSC oceanic crust, suggests that, at about this time, motion along the SITF had a left-lateral transtensional component, that accounts for its apparently broad seabed appearance westwards.
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Zhang, Ting, Guang Hua Yang, Si Ping Li, Xiu Zhong Du, and Chuan Li. "Technology for Preventing Seepage and Slide of a Stone Seawall in the Pearl River Estuary." Applied Mechanics and Materials 501-504 (January 2014): 1968–72. http://dx.doi.org/10.4028/www.scientific.net/amm.501-504.1968.
Повний текст джерелаАнотація:
The rubble mound seawall to be discussed is built on the silted floor of the Pearl River estuary. To meet the requirements of wave defending, stability and anti-seepage, foundation replacement method was used to enhance its groundsill and geomembrane was laid on the downstream slope for seepage control. However, because the silted floor in the foundation wasnt totally removed in the construction process, settlement deformation occured and the downstream slopes trended to slide down. Furthermore, due to the insufficient back pressure for seepage control, serious leakages and piping appeared on the anti-seepage body. The water leakage phenomenon showed little improvement even after additional cement grouting and plastering on the slope. In this paper, a seepage pressure stick slope reinforcement scheme is proposed to handle this problem. After the reinforcement, the water leakage has been prevented and the safety factors of the seepage and slope meets the safety requirements. The pollution caused by the seepage is also eliminated. The proposed technique can give a good reference to the other seawall reinforcement problems.
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Suprapto, Wahyono, Bambang Suharno, Johny Wahyuadi Soedarsono, and Dedi Priadi. "Analytical and Experimental Models of Porosity Formation of Duralumin Cast in Vacuum Casting System." Advanced Materials Research 277 (July 2011): 76–83. http://dx.doi.org/10.4028/www.scientific.net/amr.277.76.
Повний текст джерелаАнотація:
Porosity in cast metals often leads to cracking of components due to stress concentration and leakage, and as the result, the castings need be repaired or rejected. Disharmony in casting process was resulting in porosity. Prediction of porosity in the casting is necessary as a step to avoid the waste products and reduce costs. But to ensure whether these predictions are accurate and precise, it is still necessary to validate the test trials and testing. This paper aims to provide early information when, where, and how large a defect occurs in particular foundry casting porosity on duralumin. The analytical study of porosity formation based analytic equilibrium wt% of element, the behavior of the thermodynamic, hydrodynamic, and rules of metallurgical on vacuum casting of duralumin. Experiments as a validation study are conducted by duralumin remelting on stainless-steel bowl in a vacuum casting furnace. Analytical simulation and experiments of the casting that has been vacuumed by melting 10 cmHg pressures higher than the pressure solidification, and duralumin melt is poured automatically into permanent mold carbon steel. In the study cast duralumin created five different thicknesses. Both these studies assume the addition of copper (2.5%, 3.0%, 3.5 %, 4.0%, and 4.5% Cu) and vacuum pressure (76, 50, 40, cmHg), as independent variables, while dependent variable in the studies is porosity characteristics, which includes morphology, number and dimensions of the porosity. Optical emission spectrometry test, Reynold's and Niyama numbers, Sievert's law, Archimedes' principle (Pycnometry and Straube-Pfeiffer tests), and Eichenauer equation are instruments which are used to determine the characterization of duralumin casting porosity. Duralumin ingots remelting process was performed by the control pressure (p1) and temperature (T1). Vacuuming process performed after the smelting room temperature reaches 600 °C. Once melted, it followed by duralumin into a permanent mold (p2, T2). As a control parameter is the height of pouring (7 cm), pour temperature and mold temperature respectively at 750 °C and 300 °C. The porosity characteristics studies of two models produce two types of porosity (gas and shrinkage), the quantity dimension and porosity, and distribution of porosity in the cast duralumin.
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Butler, Edward C., Amber-Robyn Childs, Andrea Saayman, and Warren M. Potts. "Can Fishing Tourism Contribute to Conservation and Sustainability via Ecotourism? A Case Study of the Fishery for Giant African Threadfin Polydactylus quadrifilis on the Kwanza Estuary, Angola." Sustainability 12, no. 10 (May 21, 2020): 4221. http://dx.doi.org/10.3390/su12104221.
Повний текст джерелаАнотація:
It has been suggested that tourism fisheries can raise the value of landed catch, provide alternative livelihoods for local artisanal fishers and, because recreationally caught fishes are often released, simultaneously conserve stocks. However, for fishing tourism to meet ecotourism standards, sustainable, local economic benefit is imperative. This study aimed to assess the direct economic contribution of the recreational fishery for Polydactylus quadrifilis on the Kwanza Estuary, Angola. The recreational fishery contributed significantly to economic productivity in an otherwise rural area, generating a total revenue (TR) of $236,826 per four-month fishing season. Based on TR, P. quadrifilis was 3.6–32.6 times more valuable than the same fish caught and sold in the artisanal sector. However, high rates of economic leakage (86.1% of local TR) reduced the value of recreationally caught fish to below that of artisanally caught fish. Important sources of economic leakage were via the non-local sourcing of lodge supplies, services and staff and through the repatriation of profits. Capacity building within the local community is suggested to reduce leakages and to create ‘linkages’ with the recreational fishery. Greater community involvement, including the provision of business shares and greater communication and control, is suggested to achieve sustainability and incentivise the protection of recreationally important fishery species.
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Tadjer, Amine, and Reidar B. Bratvold. "Managing Uncertainty in Geological CO2 Storage Using Bayesian Evidential Learning." Energies 14, no. 6 (March 11, 2021): 1557. http://dx.doi.org/10.3390/en14061557.
Повний текст джерелаАнотація:
Carbon capture and storage (CCS) has been increasingly looking like a promising strategy to reduce CO2 emissions and meet the Paris agreement’s climate target. To ensure that CCS is safe and successful, an efficient monitoring program that will prevent storage reservoir leakage and drinking water contamination in groundwater aquifers must be implemented. However, geologic CO2 sequestration (GCS) sites are not completely certain about the geological properties, which makes it difficult to predict the behavior of the injected gases, CO2 brine leakage rates through wellbores, and CO2 plume migration. Significant effort is required to observe how CO2 behaves in reservoirs. A key question is: Will the CO2 injection and storage behave as expected, and can we anticipate leakages? History matching of reservoir models can mitigate uncertainty towards a predictive strategy. It could prove challenging to develop a set of history matching models that preserve geological realism. A new Bayesian evidential learning (BEL) protocol for uncertainty quantification was released through literature, as an alternative to the model-space inversion in the history-matching approach. Consequently, an ensemble of previous geological models was developed using a prior distribution’s Monte Carlo simulation, followed by direct forecasting (DF) for joint uncertainty quantification. The goal of this work is to use prior models to identify a statistical relationship between data prediction, ensemble models, and data variables, without any explicit model inversion. The paper also introduces a new DF implementation using an ensemble smoother and shows that the new implementation can make the computation more robust than the standard method. The Utsira saline aquifer west of Norway is used to exemplify BEL’s ability to predict the CO2 mass and leakages and improve decision support regarding CO2 storage projects.
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Balkhyour, M., and C. Crutchfield. "Effect of Feedback on Reduction of Respirator Leakage Associated with Mask Donning." Journal of King Abdulaziz University-Meteorology, Environment and Arid Land Agriculture Sciences 18, no. 2 (2007): 77–86. http://dx.doi.org/10.4197/met.18-2.6.
Повний текст джерела
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Rong, Li, Chen Lunjun, Su Ming, Zeng Qi, and Liu Yong. "Study on Friction and Wear Characteristics of Aluminum Alloy Hydraulic Valve Body and Its Antiwear Mechanism." Archives of Foundry Engineering 17, no. 1 (March 1, 2017): 207–15. http://dx.doi.org/10.1515/afe-2017-0037.
Повний текст джерелаАнотація:
Abstract In order for the working status of the aluminum alloyed hydraulic valve body to be controlled in actual conditions, a new friction and wear design device was designed for the cast iron and aluminum alloyed valve bodies comparison under the same conditions. The results displayed that: (1) The oil leakage of the aluminum alloyed hydraulic valve body was higher than the corresponding oil leakage of the iron body during the initial running stage. Besides during a later running stage, the oil leakage of the aluminum alloyed body was lower than corresponding oil leakage of the iron body; (2) The actual oil leakage of different materials consisted of two parts: the foundation leakage that was the leakage of the valve without wear and wear leakage that was caused by the worn valve body; (3) The aluminum alloyed valve could rely on the dust filling furrow and melting mechanism that led the body surface to retain dynamic balance, resulting in the valve leakage preservation at a low level. The aluminum alloy modified valve body can meet the requirements of hydraulic leakage under pressure, possibly constituting this alloy suitable for hydraulic valve body manufacturing.
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Chai, Ming Gang, Xia Hai, and Xun Wu Gong. "Study on the Application of FPGA in Magnetic Flux Leakage Acquisition System." Advanced Materials Research 694-697 (May 2013): 1354–57. http://dx.doi.org/10.4028/www.scientific.net/amr.694-697.1354.
Повний текст джерелаАнотація:
Embedded CPU in traditional magnetic flux leakage detection system was used as the master controller. CPU is serial processor, which making it difficult to collect the large amounts of real-time data. While FPGA has the advantages of high integration, high speed processing, parallel processing. FPGA is applied to magnetic flux leakage acquisition system to solve data acquisition problem. It comes up with the designs of a multi-channel magnetic flux leakage signal selection control module, A/D conversion module and communication module in VHDL language on QuartusII. The experimental results show that each module of the magnetic flux leakage acquisition system based on FPGA can meet the requirements, and can correctly collect magnetic flux leakage signal, convert and transmit data. Design of FPGA-based is programmable in the field, magnetic flux leakage collection system can be flexibly designed for different occasions, and has independent intellectual property rights.
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Zhang, Shi Bao, and Jie Wen. "Application of High Pressure Jet Grouting Technology in Seepage Prevention of ChuLou Reservoir." Applied Mechanics and Materials 238 (November 2012): 317–20. http://dx.doi.org/10.4028/www.scientific.net/amm.238.317.
Повний текст джерелаАнотація:
In view of the existing permeable sand layer and the leakage risk which threaten the earth dam foundation of Chulou reservoir, the high pressure jet grouting measure was applied to block leakage passage to solving the leakage problems of earth dam foundation. This paper mainly describes the high pressure jet grouting impermeable wall construction, including construction equipment, technological process, construction parameters and method, and wall quality detection. The test results show that the indexes such as wall depth, continuity, compressive strength, permeability coefficient meet the design requirements. The quality of impermeable wall is accepted.
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Wang, Yang, and Shiqing Wang. "Dynamic Monitoring of Low Voltage Distribution Network Leakage Detection Device Based on Internet of Things Technology." E3S Web of Conferences 252 (2021): 01006. http://dx.doi.org/10.1051/e3sconf/202125201006.
Повний текст джерелаАнотація:
The existing dynamic monitoring methods of low-voltage distribution network leakage detection device have been unable to meet the needs of the distribution network in China. Therefore, a dynamic monitoring method of low-voltage distribution network leakage detection device based on Internet of Things technology is proposed. Based on the introduction of the Internet of Things technology sensor sensing technology, the sensor is installed on the leakage detection device to obtain the operation data of the leakage detection device and preprocess it with noise reduction and normalization. At the same time, the statistical analysis of partial discharge signal is carried out to extract the characteristics of fast waveform signal (energy parameters, sample entropy and modal components). Based on the operation data features of the leakage detection device extracted above, the state diagnosis framework of the leakage detection device is built to diagnose the state of the leakage detection device, and the dynamic monitoring of the leakage detection device in low-voltage distribution network is realized. The experimental results show that: compared with the existing methods, the proposed method has stronger anti-interference ability and smaller monitoring error, which fully proves that the proposed method has better application effect.
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Caswell, Greg. "Can Electrolytic Capacitors Meet the Demands of High Reliability Applications?" International Symposium on Microelectronics 2019, no. 1 (October 1, 2019): 000364–68. http://dx.doi.org/10.4071/2380-4505-2019.1.000364.
Повний текст джерелаАнотація:
Abstract Electrolytic capacitors have long been identified as a weak link for long term high reliability applications. However, capacitor manufacturers have made significant improvements to the materials and manufacturing processes to enhance their reliability. This paper will discuss those changes, provide insight into the various failure mechanisms for electrolytic capacitors and describe appropriate accelerated tests to validate performance. We will take a deeper dive into the methodologies utilized to improve capacitor performance, e.g. foil purity and electrolyte volume. We will also discuss, from a reliability perspective, the impact of changing to a higher temperature electrolyte (from ethylene glycol to DMF, DMA and GBL) and also changes in the bung material (from butyl to EPDM). There are several environmental factors involved in the aging of electrolytic capacitors. Electrolyte loss due to drying out and leakage current due to oxide degradation are thermally related as is the self-heating associated with ripple current. The impact of the applied voltage level is also a driver as it can cause leakage current increases as well. All of these issues result in a capacitance decrease, an increase in ESR, and a change to the dissipation factor. Many other failure mechanisms associated with manufacturing will also be discussed.
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Sun, Ze Gang, Chang Niu Yang, and Lei Chen. "The Study of Mechanical Seal Leakage Detection System." Applied Mechanics and Materials 387 (August 2013): 296–300. http://dx.doi.org/10.4028/www.scientific.net/amm.387.296.
Повний текст джерелаАнотація:
The mechanical seal bench is the test platform for the leakage of the mechanical seal.The mechanical sealing leaking are closely related to the fluid pressure and temperature.The control system of the fluid pressure and temperature be designed to meet the needs of mechanical seals working in defferent conditions and the system of the leakage data acquisition and processing are designed based on C51 and C++BUILDER. The data collected be output on curve fitting.The test stand is certain guiding significance for the design and testing of the mechanical seal.
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Li, Hongchang, Fang Gao, Hehe Niu, and Fang Chang. "Application of Variable Distance Photoelectric Sensor in Precision Automatic Sowing and Fertilization." Journal of Nanoelectronics and Optoelectronics 15, no. 6 (June 1, 2020): 707–13. http://dx.doi.org/10.1166/jno.2020.2790.
Повний текст джерелаАнотація:
In order to realize the real-time monitoring of precision automatic seeding and fertilization, a monitoring system of precision automatic seeding and fertilization integrated machine based on variable distance photoelectric sensor is designed. In this system, STM32F103R8T6 single chip microcomputer hardware system is used as the lower computer to judge the running state of the machine. Through Modbus protocol, the received information is transmitted to the upper computer interface of MCGSTPC touch screen for real-time display. In the laboratory test, the designed seed metering device and fertilizer applicator can meet the requirements of wide precision sowing and wide uniform fertilization. All indicators can meet the requirements. In the field experiment, the phenomenon of seed leakage (fertilizer leakage) failure and response delay will occasionally appear. Moreover, the alarm accuracy of the monitoring system is more than 95%, and the response time of fertilizer missing, blocking and leakage is short. Therefore, the system designed in this study can realize the real-time and high-precision monitoring of precision automatic seeder, which is helpful to improve the quality of precision seeder.
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Ulas, Abdullah, Alim Aydin, Firdes Ulas, Halit Yetisir, and Tanveer Fatima Miano. "Cucurbita Rootstocks Improve Salt Tolerance of Melon Scions by Inducing Physiological, Biochemical and Nutritional Responses." Horticulturae 6, no. 4 (October 14, 2020): 66. http://dx.doi.org/10.3390/horticulturae6040066.
Повний текст джерелаАнотація:
A hydroponic experiment was conducted to assess whether grafting with Cucurbita rootstocks could improve the salt tolerance of melon scions and to determine the physiological, biochemical, and nutritional responses induced by the rootstocks under salt stress. Two melon (Cucumis melo L.) cultivars (Citirex and Altinbas) were grafted onto two commercial Cucurbita rootstocks (Kardosa and Nun9075). Plants were grown in aerated nutrient solution under deep water culture (DWC) at two electrical conductivity (EC) levels (control at 1.5 dS m−1 and salt at 8.0 dS m−1). Hydroponic salt stress led to a significant reduction in shoot and root growths, leaf area, photosynthetic activity, and leaf chlorophyll and carotenoid contents of both grafted and nongrafted melons. Susceptible plants responded to salt stress by increasing leaf proline and malondialdehyde (MDA), ion leakage, and leaf Na+ and Cl− contents. Statistically significant negative correlations existed between shoot dry biomass production and leaf proline (r = −0.89), leaf MDA (r = −0.85), leaf Na+ (r = −0.90), and leaf (r = 0.63) and root (r = −0.90) ion leakages under salt stress. Nongrafted Citirex tended to be more sensitive to salt stress than Altinbas. The Cucurbita rootstocks (Nun9075 and Kardosa) significantly improved growth and biomass production of grafted melons (scions) by inducing physiological (high leaf area and photosynthesis), biochemical (low leaf proline and MDA), and nutritional (low leaf Na+ and ion leakage and high K+ and Ca++ contents) responses under salt stress. The highest growth performance was exhibited by the Citirex/Nun9075 and Citirex/Kardosa graft combinations. Both Cucurbita cultivars have high rootstock potential for melon, and their significant contributions to salt tolerance were closely associated with inducing physiological and biochemical responses of scions. These traits could be useful for the selection and breeding of salt-tolerant rootstocks for sustainable agriculture in the future.
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Yang, Li Jian, Yang Zhao, and Song Wei Gao. "Discharge Speed Control of In-Pipe Detector in Gas Pipeline." Advanced Materials Research 459 (January 2012): 338–42. http://dx.doi.org/10.4028/www.scientific.net/amr.459.338.
Повний текст джерелаАнотація:
The in-pipe detector with magnetic flux leakage runs along the pipeline under the effect of gas flow field, completing the pipeline wall excitation, magnetic flux leakage testing, etc. Excitation within the detector on the wall and the adequacy of magnetic flux leakage signal acquisition is complete are decided by speed of in-pipe detector. In this paper, mathematical model simulation is established and the actual experiment is proposed. Simulation and experiment results show that after a long time running, in-pipe detector with different discharge area have respective upper speed limit. According to references and experiment results, the in-pipe detector with 40% discharge area is meet the detection accuracy and have the maximum detection efficiency under work conditions described in this paper
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冯, 仲. "Gas Seal Leakage’s Analysis and Improvement of 4M50 New Hydrogen Compressor." Mechanical Engineering and Technology 01, no. 04 (2012): 57–60. http://dx.doi.org/10.12677/met.2012.14011.
Повний текст джерела
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Jia, Jin, Xiujuan Wang, Junli Lv, Shan Gao, and Guoze Wang. "Alternating Magnetic Field Prior to Cutting Reduces Wound Responses and Maintains Fruit Quality of Cut cucumis melo L. cv Hetao." Open Biotechnology Journal 9, no. 1 (November 2, 2015): 230–35. http://dx.doi.org/10.2174/1874070701509010230.
Повний текст джерелаАнотація:
The quality of fruit targeted for human consumption is affected greatly by the methods used in processing. The objective of this study was to assess a method of treating cantaloupe melons to reduce the wound responses incurred by cutting while maintaining fruit quality. After being treated with an alternating magnetic field (AMF) at the strength of 2mT for 0, 5, 10, 15, 20, or 25 min, Cucumis melo fruits were cut longitudinally into five pieces and stored at 5°C until analysis. The rates of decomposition, electrolyte leakage and respiration, were determined along with fruit firmness, soluble solids and titratable acids. Cutting the melons damaged the quality of fruits, as indicated by lower firmness soluble solids, higher electrolyte leakage, decomposition, respiration and titratable acids in cut slices compared to intact melons. Treatment with AMF before cutting influenced all parameters above, compared to untreated samples, and treatment with 2mT for 15 min resulted in reduced respiration rates, lower electrolyte leakage, delayed softening and decomposition, and reduced flows of soluble solids and titratable acid. Therefore, application of AMF treatment prior to cutting is beneficial for reducing wound responses and maintaining quality and flavor of cut Cucumis melo L. cv, which could provide a useful means to increase the market share of this popular fruit crop species.
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Luan, Zhi Bo, Hou Hua Pang, and Xiao Dong Tan. "The Numerical Analysis of Leakage in Ultrahigh Pressure Seal Structure." Applied Mechanics and Materials 248 (December 2012): 433–37. http://dx.doi.org/10.4028/www.scientific.net/amm.248.433.
Повний текст джерелаАнотація:
This article states seal clearance and fluid leakage.By means of pressure distribution calculation and theoretical analysis, theoretically it establishs the mathematical model of the leakage with liquid material, the sealing structure and the fuel tank between the internal and external pressure.The whole processes on Matlab platform meet the complex engineering requirements,so the calculation process is simple and convenient. By calculating the results should be very intuitive, it closes to the sealing gap and leakage distribution curve. Thus, it is sure sealing clearance is the first element in the ultra-high pressure seal system.
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Rizaliansyah, Ferdian, Aryati Aryati, and Musofa Rusli. "PLASMA LEAKAGE PROFILES OF DENGUE HEMORRHAGIC FEVER PATIENTS IN RSUD Dr. SOETOMO, SURABAYA, EAST JAVA, INDONESIA JANUARY – JUNE 2014." Indonesian Journal of Tropical and Infectious Disease 6, no. 4 (August 22, 2017): 92. http://dx.doi.org/10.20473/ijtid.v6i4.3456.
Повний текст джерелаАнотація:
Plasma leakage is one crucial point of dengue hemorrhagic fever (DHF) that differentiates it from dengue fever (DF). DHF has to meet 4 criteria which are 2 – 7 days of acute fever, hemorrhagic manifestation, thrombocytopenia (≤100.000 cells/mm3) and evidence of plasma leakage. Plasma leakage consists of increasing hematocrit ≥20%, hypoalbuminemia or evidence of pleural effusion or ascites. Often doctors only base their DHF diagnosis on the presence of thrombocytopenia. This study analyzed the presence of plasma leakage between adult and pediatric patients with a DHF diagnosis in RSUD Dr. Soetomo in order to make the diagnosis and healthcare services better in the future. This was a retrospective study which used medical records of DHF patients admitted from January to June 2014. 78 cases were included, 24 adult patients (31%) and 54 pediatric patients (69%). 29/78 (37%) patients had no evidence of plasma leakage. No adult patients had ascites whereas 11/54 (20%) pediatric patients presented with ascites. No adult patients had pleural effusion whereas 25/54 (53%) pediatric patients did. Most adult patients that had serum albumin checked had normal albumin levels (12/14 [86%]) while only 14/28 (52%) pediatric patients had normal albumin level. 5/22 (23%) adult patients versus 32/53 (60%) pediatric patients showed hematocrit increments ≥20%. Patients admitted with dengue virus infection may currently be often misclassified as DHF because there are no plasma leakage manifestation in some patients.. There are significant differences in plasma leakage manifestations between adult and pediatric patients which poses a theory that pediatric patients are more susceptible to have plasma leakage manifestations than adult patients.
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Gharde, Swaroop, Gaurav Sharma, and Balasubramanian Kandasubramanian. "Hot-Melt Adhesives: Fundamentals, Formulations, and Applications: A Critical Review." Reviews of Adhesion and Adhesives 8, no. 1 (March 1, 2020): 1–28. http://dx.doi.org/10.7569/raa.2020.097301.
Повний текст джерелаАнотація:
Hot-Melt Adhesives (HMAs) are typically used in applications where instant sealing is critically required. HMAs are generally preferred for those applications where processing speed is critical. These materials are widely used in various engineering applications, mainly as sealants in leakages and crack filling of walls and roofs. The industrial use of HMAs is most common in glassware and automobiles for gluing glasses in buildings and bonding heavy motor parts. The formulation of HMAs contains a polymer of suitable nature that makes the base for a strong adhesive, and waxes are added to increase the settling time of adhesive. The tackifiers are used to dilute the polymer to adjust the Glass Transition Temperature (Tg) and to reduce the viscosity for proper flow of hot-melt. This review intends to comprehensively discuss the preparation and formulations of HMAs using various polymer matrices, along with their applications and mechanics. The designing of green HMAs has been discussed in the literature and have been promoted over conventional solvent-based HMAs due to their functionality without Volatile Organic Compounds (VOCs). Various measures, challenges, and resolutions for making hazard-free HMAs have been discussed in the present review.