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1
Tijing, Leonard, John Ryan Dizon et Gil Cruz Jr. « 3D-Printed Absorbers for Solar-Driven Interfacial Water Evaporation : A Mini-Review ». Advance Sustainable Science, Engineering and Technology 3, no 1 (30 avril 2021) : 0210103. http://dx.doi.org/10.26877/asset.v3i1.8367.
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Solar-driven interfacial water evaporation (SWE) is considered as a promising sustainable solution for clean water production especially for remote and off-grid communities. Various approaches have been developed in the last decade to improve the evaporation and thermal efficiency of the system, and to make it more robust for long-term operation. In recent years, 3D printing has emerged as an attractive method to fabricate simple and complex absorber geometries for SWE. In this mini-review, we present the new developments of 3D-printed solar absorbers including the various designs, fabrication strategies, challenges and opportunities. This study hopes to provide more insights into the use of additive manufacturing for improving the absorber design and performance of SWE.
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Chintalapudi, Ravikiran, Sidda Reddy B, Siva Rama Krishna V, Sundeep Moyya, Shaik Hussain et Ujwala Sriram. « Effect of Vibration Control Mechanisms on the Vibrational Behavior of Al 6061/SiC Composite Beam ». MATEC Web of Conferences 405 (2024) : 02003. http://dx.doi.org/10.1051/matecconf/202440502003.
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A machine in action in a plant mine or other mechanical system is a major source of vibrations that spread from foundation and across the surrounding area. There should be the least amount of vibrations possible. The vibrations must be isolated, absorbed, or dampened in order to do this. This study investigates how an oil damper and various types of vibration isolators affect vibration frequency of a stir cast composite beam made up of 90% Al6061 and 10% SiC to examine the influence of an oil damper well, as single and double absorbers on the vibration frequency of a stir cast composite beam. Investigating the frequencies on the Vibration Fundamental Trainer under fixed-hinged, hinged-hinged, and fixed-free boundary conditions. The experiments were carried out on the constructed composite beam. The results indicate that the absorbers vibration amplitudes decrease, along with the damper and isolators effects. Absorber and isolator frequencies observed were lower, than the frequency. Increased beam holes resulted in decreased stiffness and reduced frequencies. Compared to scenarios the frequencies were higher when the beam had fixed end conditions without holes. When compared to absorbers and isolators, oil dampers have more effectively decreased vibrations.
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Rakasiwi, Rinjani, Syaifurrahman Syaifurrahman, Wivina Diah I et Usman A. Gani. « KAJIAN EFISIENSI PANAS KOLEKTOR PEMANAS AIR SURYA PADA MOBILE MINI BIODIESEL PLANT ». Jurnal Rekayasa Mesin 13, no 3 (31 décembre 2022) : 795–804. http://dx.doi.org/10.21776/jrm.v13i3.1209.
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Integration of solar water heating system and biodiesel unit process has resulted a prototype called Mini Biodiesel Plant. The key of that unit is the effectiveness of heat transfer that occured in the solar collector. The purpose of this research is to analyze the performance of the collector from the solar water heating system. The solar collector used is a flat plate type with a surface area of 0.7m2. It consists of a glass cover, alummunium absorber, styrofoam insulator and woof frame. Based on the research result for 5 times for 5 hours each day, the highest of intensity of solar radiation (I) was 859 W/m2 can produce maximum hot water (Ta) of 62oC. The average of real heat has been absorbes by teh collector (Qu) was 271 Watt while the maximum of heat loss (Qloss) was 144.6 Watt therefore the average of collector efficiency (ƞ) was 45.1%.
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Itoh, Daisuke, Toru Misawa, Takashi Horiuchi et Kentaro Aoki. « Search for intrinsic NALs in BAL/mini-BAL quasar spectra ». Monthly Notices of the Royal Astronomical Society 499, no 3 (21 septembre 2020) : 3094–110. http://dx.doi.org/10.1093/mnras/staa2793.
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ABSTRACT Some fraction of narrow absorption lines (NALs) are physically associated to the quasar/host-galaxy materials (i.e. intrinsic NALs) like those of broad absorption lines (BALs) and mini-BALs. The relation between these three types of absorption lines has not been understood yet, however one interpretation is that these absorption features correspond to different inclination angles. In this study, we search for intrinsic NALs in 11 BAL/mini-BAL quasar spectra retrieved from VLT/UVES public archive, in order to test a possible relation of intrinsic NALs and BALs/mini-BALs in the geometry models. We use partial coverage analysis to separate intrinsic NALs from ones which are associated to cosmologically intervening materials like foreground galaxies and intergalactic medium (i.e. intervening NALs). We identify one reliable and two possible intrinsic NAL systems out of 36 NAL systems in 9 BAL/mini-BAL quasar spectra after removing two quasars without clear BAL features. In spite of a small sample size, we placed a lower limit on the fraction of BAL/mini-BAL quasars that have at least one intrinsic C iv NAL ($\sim 33^{+33}_{-18}{{\ \rm per\ cent}}$). This can be interpreted that intrinsic NAL absorbers exist everywhere regardless of inclination angle. We found that one of the intrinsic NAL systems detected in SDSS J121549.80−003432.1 is located at a large radial distance of R > 130 kpc, using a method of photoionization model with ground/excited-state lines. Considering the wide range of intrinsic NAL absorber distribution in inclination angles and radial distances, it suggests that origins and geometry of them are more complicated than we expected.
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Zhang, Zeng Zhi, Na Gu et Ji Fei Zhang. « The Application of Aqueous Span 80 Composite Material in Methane Absorption and Explosion Suppression ». Materials Science Forum 610-613 (janvier 2009) : 125–29. http://dx.doi.org/10.4028/www.scientific.net/msf.610-613.125.
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This paper aims to design a sort of aqueous atomization absorbing material which can absorb mine gas under coal mine to decrease the methane concentration and reduce the explosion hazard. The material was composed of water as matrix, Span 80 as methane absorbent, and inorganic salt as additive. Methane the main component of mine gas was used as model of mine gas. The influence of concentration of inorganic salt on absorption and the effect of different compound materials made of Span 80 and inorganic salt on absorption were studied using Head Space Gas Chromatography to determine the content of methane absorbed. Explosion chamber was used as experiment system to simulate mine gas explosion. The explosion suppression effects of absorbing materials were studied preliminarily in explosion chamber using the maximum explosion pressure and residual methane content after explosion as parameters. The results indicate that the absorbing material can absorb more methane than water and can partly inhibit the explosion of the mixture of methane and air.
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ASTE, Patrik, Eric BRANDãO, Jacques CUENCA, Mélanie NOLAN, U. Peter SVENSSON et Elias ZEA. « Experimental validity of using a ResNet to predict sound absorption coefficients of finite samples ». INTER-NOISE and NOISE-CON Congress and Conference Proceedings 270, no 3 (4 octobre 2024) : 7999–8005. http://dx.doi.org/10.3397/in_2024_4035.
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The validity of using a neural network to predict sound absorption coefficients of finite porous materials is tested with experimental data with a flush-mounted glass wool sample on a baffle. The network is pre-trained and validated with numerical simulations of flushed-mounted finite absorbers using a Delany-Bazley-Miki model. The experimental setup consists of a 12 x 12 microphone array placed above the absorber and a sound source placed at angles of 0, 40, and 75 degrees with respect to the normal of the sample. The sound absorption coefficients predicted at normal incidence by the network are compared with the impedance tube method as a reference result.
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Joe, Jemee, Hyunwoo Yang, Changdeuck Bae et Hyunjung Shin. « Metal Chalcogenides on Silicon Photocathodes for Efficient Water Splitting : A Mini Overview ». Catalysts 9, no 2 (2 février 2019) : 149. http://dx.doi.org/10.3390/catal9020149.
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In the photoelectrochemical (PEC) water splitting (WS) reactions, a photon is absorbed by a semiconductor, generating electron-hole pairs which are transferred across the semiconductor/electrolyte interface to reduce or oxidize water into oxygen or hydrogen. Catalytic junctions are commonly combined with semiconductor absorbers, providing electrochemically active sites for charge transfer across the interface and increasing the surface band bending to improve the PEC performance. In this review, we focus on transition metal (di)chalcogenide [TM(D)C] catalysts in conjunction with silicon photoelectrode as Earth-abundant materials systems. Surprisingly, there is a limited number of reports in Si/TM(D)C for PEC WS in the literature. We provide almost a complete survey on both layered TMDC and non-layered transition metal dichalcogenides (TMC) co-catalysts on Si photoelectrodes, mainly photocathodes. The mechanisms of the photovoltaic power conversion of silicon devices are summarized with emphasis on the exact role of catalysts. Diverse approaches to the improved PEC performance and the proposed synergetic functions of catalysts on the underlying Si are reviewed. Atomic layer deposition of TM(D)C materials as a new methodology for directly growing them and its implication for low-temperature growth on defect chemistry are featured. The multi-phase TM(D)C overlayers on Si and the operation principles are highlighted. Finally, challenges and directions regarding future research for achieving the theoretical PEC performance of Si-based photoelectrodes are provided.
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Tandangi, Rahmayani, Jamaluddin Jamaluddin et Lahming Lahming. « Modifikasi Lemari Pendingin Mini untuk Mendinginkan Buah Pisang Menggunakan Pasir sebagai Absorben Kalor ». Jurnal Pendidikan Teknologi Pertanian 5, no 2 (10 février 2020) : 91. http://dx.doi.org/10.26858/jptp.v5i2.9937.
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Penelitian ini bertujuan untuk mengetahui proses perancangan lemari pendingin mini untuk mendinginkan buah pisang menggunakan pasir sebagai absorben kalor dan unjuk kerja pada lemari pendingin hasil rancangan menggunakan pasir sebagai absorben kalor. Bentuk penelitian ini adalah modifikasi alat. Data penelitian diperoleh dari hasil pengujian alat dengan cara melakukan uji coba perbandingan antara penyimpanan pada suhu lemari dan suhu ruang. Modifikasi alat lemari pendingin mini menggunakan pasir sebagai absorben kalor dirancang untuk mengurangi dampak pemanasan global akibat penggunaan freon dan memperlambat proses kerusakan pada buah. Teknik analisis data dilakukan secara kuantitatif dengan statistik deskriftif. Hasil penelitian menunjukkan bahwa suhu yang ada pada lemari yaitu 24°C.
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Kurniawati, Ischia, et Yonmo Sung. « A Review of Heat Dissipation and Absorption Technologies for Enhancing Performance in Photovoltaic–Thermal Systems ». Energies 17, no 7 (3 avril 2024) : 1721. http://dx.doi.org/10.3390/en17071721.
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With the growing demand for photovoltaic (PV) systems as a source of energy generation that produces no greenhouse gas emissions, effective strategies are needed to address the inherent inefficiencies of PV systems. These systems typically absorb only approximately 15% of solar energy and experience performance degradation due to temperature increases during operation. To address these issues, PV–thermal (PVT) technology, which combines PV with a thermal absorber to dissipate excess heat and convert it into additional thermal energy, is being rapidly developed. This review presents an overview of various PVT technologies designed to prevent overheating in operational systems and to enhance heat transfer from the solar cells to the absorber. The methods explored include innovative absorber designs that focus on increasing the heat transfer contact surface, using mini/microchannels for improved heat transfer contiguity, and substituting traditional metal materials with polymers to reduce construction costs while utilizing polymer flexibility. The review also discusses incorporating phase change materials for latent heat absorption and using nanofluids as coolant mediums, which offer higher thermal conductivity than pure water. This review highlights significant observations and challenges associated with absorber design, mini/microchannels, polymer materials, phase change materials, and nanofluids in terms of PV waste heat dissipation. It includes a summary of relevant numerical and experimental studies to facilitate comparisons of each development approach.
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Bess, John D., Gray S. Chang, Patrick Moo et Julie Foster. « Mini-Reactor Proliferation-Resistant Fuel with Burnable Gadolinia in Once-Through Operation Cycle Performance Verification ». Journal of Nuclear Engineering 5, no 3 (28 août 2024) : 318–29. http://dx.doi.org/10.3390/jne5030021.
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A miniature nuclear reactor is desirable for deployment as a localized nuclear power station in support of a carbon-free power supply. Coupling aspects of proliferation-resistant fuel with natural burnable absorber loading are evaluated for once-through operation cycle performance to minimize the need for refueling and fuel shuffling operations. The incorporation of 0.075 wt.% 237Np provides favorable plutonium isotopic vectors throughout an operational lifetime of 5.5 years. providing 35 MWe. Core performance was assessed using a verification-by-comparison approach for core designs with or without 237Np and/or gadolinia burnable absorber. Burnup Monte Carlo calculations were performed via MCOS coupling of MCNP and ORIGEN to an achievable burnup of ~62.5 GWd/t. The results demonstrate a minimal penalty to reactor performance due to the addition of these materials as compared against the reference design. Coupling of a proliferation-resistant fuel concept with a uniform loading of natural gadolinia burnable absorber for LEU+ fuel (7.5 wt.% 235U/U UO2) provides favorable excess reactivity considerations with minimized concerns for additional residual waste and more uniform distribution of un-depleted 235U in discharged fuel assemblies.
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Zea, Elias, Eric Brandão, Mélanie Nolan, Jacques Cuenca, Joakim Andén et U. Peter Svensson. « Sound absorption estimation of finite porous samples with deep residual learning ». Journal of the Acoustical Society of America 154, no 4 (1 octobre 2023) : 2321–32. http://dx.doi.org/10.1121/10.0021333.
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This work proposes a method to predict the sound absorption coefficient of finite porous absorbers using a residual neural network and a single-layer microphone array. The goal is to mitigate the discrepancies between predicted and measured data due to the finite-size effect for a wide range of rectangular absorbers with varying dimensions and flow resistivity and for various source-receiver locations. Data for training, validation, and testing are generated with a boundary element model consisting of a baffled porous layer on a rigid backing using the Delany–Bazley–Miki model. In effect, the network learns relevant features from the array pressure amplitude to predict the sound absorption as if the porous material were infinite. The method's performance is quantified with the error between the predicted and theoretical sound absorption coefficients and compared with the two-microphone method. For array distances close to the porous sample, the proposed method performs at least as well as the two-microphone method and significantly better than it for frequencies below 400 Hz and small absorber sizes (e.g., 20 × 20 cm2). The significance of the study lies in the possibility of measuring sound absorption on-site in the presence of strong edge diffraction.
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Yadao, Adik, et R. S. Hingole. « Modeling and analysis of impact energy absorber by using ls dyna ». World Journal of Engineering 12, no 1 (1 février 2015) : 23–28. http://dx.doi.org/10.1260/1708-5284.12.1.23.
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Today’s car is one of the most important things in everyone’s life .Every person wants to have his or her own car but the question that arises in each buyer’s mind is whether the vehicle is safe enough to spend so much of money so it is the responsibility of an mechanical engineer to make the vehical comfortable and at the Same time safer. Now a days automakers are coming with various energy absorbing devices such as crush box, door beams etc. this energy absorbing device s prove to be very useful in reducing the amount force that is being transmitted to the occupant. In this we are using impact energy absorber in efficient manner as compare to earlier. The various steps involved in this project starting from developing the cad model of this inner impact energy absorber using the CAD software CATIA V5 R19. Then pre-processing is carried out in HYPERMESH 11.0 which includes assigning material, properties, boundary conditions such as contacts, constraints etc. LS-DYNA971 is used as a solver and LS-POST is used for the post processing and results obtained are compared to the standards. By carrying out this idea it has been observed that there is a considerable amount of energy that is being absorbed by this energy-absorbing device. Along with this energy absorption, the intrusion in passenger compartment is also reduced by considerable amount. So for safer and comfortable car with inner impact energy absorber is one of the best options available. This will get implement by this research work.
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Chhillar, Monika, et Deepak Kukkar. « A mini-review on non-enzymatic electrochemical biosensing techniques for creatinine determination ». E3S Web of Conferences 509 (2024) : 02001. http://dx.doi.org/10.1051/e3sconf/202450902001.
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The escalation of industrial activities over the past century has significantly heightened human exposure to heavy metals, posing grave threat to the health as well as the environment. Cadmium, mercury, and lead are few of the many heavy metals. They are prevalent pollutants and are absorbed, retained, and accumulated within the human body. On the basis of the absorbed dosage, exposure route, and duration, the range of the toxicity fluctuate. While these metals are essential in limited quantities, excessive exposure can lead to severe health complications and disorders. This review examines the mechanisms and adverse effects of cadmium, mercury, and lead on human health when present in exceedingly large amounts.
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Samsudin, Emedya Murniwaty, Lokman Hakim Ismail, Aeslina Abd Kadir, Ida Norfaslia Nasidi et Noor Sahidah Samsudin. « Rating of Sound Absorption for EFBMF Acoustic Panels according to ISO 11654:1997 ». MATEC Web of Conferences 150 (2018) : 03002. http://dx.doi.org/10.1051/matecconf/201815003002.
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Empty fruit bunch fibre (EFB) and mesocarp fibre (MF) have been used in the fabrication of a new acoustic panel as a sound absorber for building. Measurements were carried out following ISO 354 in the mini reverberation chamber and the sound absorption performance of EFBMF acoustic panels were rated based on ISO 11654. Measurements of the new EFBMF acoustic panel involves five panel designs of 100 EFB dust panels, 80:20 dust panels, 100MF coir panels, 90:10 coir panels and 50:50 coir panels with 5 cm of initial thickness. Results showed that 100MF coir panel achieved αw of 0.90 coefficient and was rated as Class A absorber followed by 90:10 coir panels with αw of 0.85 coefficient and 100 EFB dust, 80:20 dust and 50:50 coir panels having αw of 0.80 coefficients and been rated as Class B absorber. This research has successfully defined that EFB and MF are viable to be used as raw fibre for acoustic absorber for building.
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Dama, Firdaut Loja, Dominggus G. H. Adoe et Matheus Magnus Dwinanto. « Studi Eksperimen dan Simulasi Termodinamika Mini Refrigerator ». LONTAR Jurnal Teknik Mesin Undana 10, no 02 (31 octobre 2023) : 23–28. http://dx.doi.org/10.35508/ljtmu.v10i02.13648.
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Household refrigeration machines (fridges) are household appliances that are widely used in families in Indonesia. However, the use of working fluids still uses this type of working fluid which causes thinning of the ozone layer and global warming. Therefore, this research aims to analyze the effect of evaporation temperature on work coefficient and exergy efficiency by using R600a working fluid as an environmentally friendly fluid. This research uses experimental and simulation methods using Cooltols software. The research results show that increasing the evaporation temperature has an impact on increasing the work coefficient, the heat absorbed by the evaporator but reducing the compressor power, and the heat released by the condenser. The greatest increase in exergy destruction is found in the evaporator, where exergy efficiency increases. So R600a is very suitable for use in refrigerators.
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Yu, Bin, Zhice Wang, Guoye Wang, Jianzhu Zhao, Liyang Zhou et Jie Zhao. « Investigation of the suspension design and ride comfort of an electric mini off-road vehicle ». Advances in Mechanical Engineering 11, no 1 (janvier 2019) : 168781401882335. http://dx.doi.org/10.1177/1687814018823351.
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In view of the little research that has been conducted on the ride comfort of mini vehicles, an electric mini off-road vehicle was designed in this study and a 2 degree-of-freedom quarter car model was established to investigate the ride comfortability. The amplitude-frequency and vibration response characteristics of the suspension were analyzed with the natural frequencies of the front and rear suspensions selected in accordance with the required driving performance. A comprehensive objective function with respect to the safety and comfortability was established, and the damping ratio of the suspension was determined. The damping characteristics of the shock absorber were analyzed to derive an adjustment rule of the suspension damping ratio. The piecewise linear speed characteristics of the shock absorber were subsequently obtained, and suspension-parameter identification and ride comfort tests were conducted. The test results showed that the natural frequencies and damping ratios of the front and rear suspensions were 1.676 and 1.922 Hz, and 0.225 and 0.242, respectively. The results of a pulse input test and D-level road random running test also demonstrated the safety and good ride comfortability of the vehicle.
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Atipo, M., O. Olarinoye, B. Awojoyogbe et M. Kolo. « High Terrestrial Radiation Level in an Active Tin-Mine at Jos South, Nigeria ». Journal of Applied Sciences and Environmental Management 24, no 3 (23 avril 2020) : 435–42. http://dx.doi.org/10.4314/jasem.v24i3.6.
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Mineral mining and milling can be a source of national economic and technological development. However, mining of minerals has been confirmed to disturb the natural distribution of radioisotopes in the soil, air and water bodies in the biota. In an attempt to evaluate the radiological burden resulting from tin mining activities at Rayfield-Du area of Jos, the background gamma-radiation level in the mine was measured via a well calibratedhand-held dosimeter placed at 1 m above ground level. The mean absorbed dose rate, annual effective dose rate and excess lifetime cancer risk for the mine was 0.83 μSvh-1; 1.44 mSv-1 and 0.005 respectively. Generally, dose rates were higher in the mine pits and processing areas as compared to administrative areas of the mine. The mean measured dose rate and calculated dose parameters for the mine were all high when compared to the regulatory limit for public exposure. The potential of developing radiation-induced health defects as a result of high radiation absorbed dose rate by the miners and dwellers around the mine is highly probable.
Keywords: Gamma-radiation; mine; absorbed dose rate; radiation exposure.
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Strandh, Margareta, et Sven-Erik Strand. « In Vivo Absorbed Dose Measurements with Mini-TLDs Parameters affecting the reliability ». Acta Oncologica 35, no 6 (janvier 1996) : 713–19. http://dx.doi.org/10.3109/02841869609084004.
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DellaNeva, JoAnn. « Reflecting Lesser Lights : The Imitation of Minor Writers in the Renaissan* ». Renaissance Quarterly 42, no 3 (1989) : 449–79. http://dx.doi.org/10.2307/2862079.
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In a probing article that appeared not very long ago in this journal, G. W. Pigman III called attention to the following passage from Petrarch's Familiares which deals with the Italian author's unconscious reminiscence from well-known and often-read authoritative works:I have read Virgil, Flaccus, Severinus, Tullius not once but countless times … . I ate in the morning what I would digest in the evening, I swallowed as a boy what I would ruminate upon as an older man. I have thoroughly absorbed these writings, implanting them not only in my memory but in my marrow, and they have so become one with my mind that were I never to read them for the remainder of my life, they would cling to me, having taken root in the innermost recesses of my mind. But sometimes I may forget the author, since through long usage and continual possession I may adopt them and for some time regard them as my own; and besieged by the mass of such writings, I may forget whose they are and whether they are mine or others'.
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Nishioka, Kensuke, et Yasuyuki Ota. « Heat Release Effect of Thermal Emission Coating on Concentrator Photovoltaic Module ». Applied Mechanics and Materials 372 (août 2013) : 559–62. http://dx.doi.org/10.4028/www.scientific.net/amm.372.559.
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A thermal emission layer was coated on the aluminum chassis of a concentrator photovoltaic (CPV) module. The cell temperature in the CPV mini-module with the white thermal emission coating was 3 - 5°C lower than that in the CPV mini-module without the thermal emission coating. The effect of the high-radiation layer was remarkable. In spite of the high emissivity of the black thermal emission coating, the effect of the black coating was not remarkable. This is because the scattered light from environment is absorbed by the black coating and the CPV mini-module is heated. The color of CPV is important and the white coating is better than the black coating.
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Ethaib, Saleem, Rozita Omar, Siti Mazlina Mustapa Kamal, Dayang Radiah Awang Biak et Salah L. Zubaidi. « Microwave-Assisted Pyrolysis of Biomass Waste : A Mini Review ». Processes 8, no 9 (19 septembre 2020) : 1190. http://dx.doi.org/10.3390/pr8091190.
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The utilization of biomass waste as a raw material for renewable energy is a global concern. Pyrolysis is one of the thermal treatments for biomass wastes that results in the production of liquid, solid and gaseous products. Unfortunately, the complex structure of the biomass materials matrix needs elevated heating to convert these materials into useful products. Microwave heating is a promising alternative to conventional heating approaches. Recently, it has been widely used in pyrolysis due to easy operation and its high heating rate. This review tries to identify the microwave-assisted pyrolysis treatment process fundamentals and discusses various key operating parameters which have an effect on product yield. It was found that several operating parameters govern this process such as microwave power and the degree of temperature, microwave absorber addition and its concentration, initial moisture content, initial sweep gas flow rate/residence time. Moreover, this study highlighted the most attractive products of the microwave pyrolysis process. These products include synthesis gas, bio-char, and bio-oil. The benefits and challenges of microwave heating are discussed.
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Silvia CR, Wilma Delphine, Rashmi R N et Venkatesha. « Zing thing about zinc : A mini review ». International Journal of Clinical Biochemistry and Research 8, no 3 (15 octobre 2021) : 169–75. http://dx.doi.org/10.18231/j.ijcbr.2021.036.
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Zinc is a micromineral present in the body tissues and fluids. Zinc is absorbed from the duodenum and stored in the form of metallothionine in the liver and excreted through sweat. Zinc plays a vital role in protein biosynthesis, gene expression; it also acts as an antioxidant and is used in the growth of the fungus. Due to the deficiency of zinc, a patient will be suffering from poor wound healing, lesions of skin, impaired spermatogenesis, hyperkeratosis, dermatitis and alopecia.An unprecedented COVID-19 pandemic caused by a novel corona virus called SARS-CoV-2, produces severe acute respiratory distress syndrome (ARDS). Zinc is used to treat COVID 19 because it improves the immunity. As the COVID patients are susceptible to zinc deficiency, they are prescribed with zinc supplements. Intake of zinc more than1000mg/day causes Zinc toxicity. Fungus utilises zinc for its growth. Mucormycosis caused by fungus Rhizopus species seen in most of the post COVID patients. Since, Zinc has assumed importance in this COVID 19 pandemic, this review article unfathoms the explicit roles of Zinc in humans.
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SHADRACK CHUKWUEBUKA UGWU et CHIZOBA MAY OBELE. « A mini-review on expanded polystyrene waste recycling and its applications ». World Journal of Advanced Engineering Technology and Sciences 8, no 1 (28 février 2023) : 315–29. http://dx.doi.org/10.30574/wjaets.2023.8.1.0057.
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Over the years, waste recycling has been a growing concern among many nations of the world, especially in developing countries. Expanded polystyrene (EPS) is used in electrical/electronic appliances as a shock absorber and constitutes a reasonable percentage of the entire plastic waste. There are three methods of recycling expanded polystyrene: mechanical, chemical, and thermal recycling; each of the above methods gives rise to different products that are used in different applications. Expanded polystyrene is used as a binder in emulsion paint as a replacement for conventional binders; as a component of asphalt used in road construction; as a component of wood plastic composites; as a blend with silica and in concrete to produce lightweight construction material. This article studied the various applications of recycled polystyrene waste from mechanical, chemical, and thermal methods of waste recycling.
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Sabere, Awis Sukarni Mohmad, et Mohd Muzamir Mahat. « The Effect of Particle Size on the Physical Characteristics and Drug-release Behavior of Mini-tablets ». Trends in Sciences 18, no 21 (13 octobre 2021) : 43. http://dx.doi.org/10.48048/tis.2021.43.
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This study aimed to investigate the influence of particle size of the excipients on the behavior of mini-tablets in terms of physical characteristics and drug release profiles. Material and methods: All of the mini-tablets based on HPMC, PEG 6K and PEO 8M PVP produced high quality mini-tablets from both sieve fractions while 90F was very fragile. Results: Crushing strength values were the most pronounced difference between the mini-tablets from all formulations. The PEO 8M-based mini-tablets showed the highest values and deformation behavior instead of fracture. Water absorption and drug release profiles also showed intriguing and different results between the various formulations. Conclusion: The results suggested that even though different particle size has limited effect on the physical characteristic of the product, it may have a significant effect on its drug dissolution profile. HIGHLIGHTS The particle size of powders or granules can influence the physical properties and release profiles of tablets, particularly mini-tablets PEG 6K and PEO 8M mini-tablets from the larger sieve fraction variation absorbed less moisture and released drugs faster than their counterparts, whereas HPMC and PVP 90F mini-tablets from both sieve fractions exhibited a similar pattern in terms of moisture uptake and drug release profiles PEO 8M mini-tablets of both sieve fractions displayed almost linear release profiles with the highest crushing strength than the rest of the formulations GRAPHICAL ABSTRACT
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Li, Changxiu, Vitalyi Gusev, Emmanouil Dimakis, Thomas Dekorsy et Mike Hettich. « Broadband Photo-Excited Coherent Acoustic Frequency Combs and Mini-Brillouin-Zone Modes in a MQW-SESAM Structure ». Applied Sciences 9, no 2 (15 janvier 2019) : 289. http://dx.doi.org/10.3390/app9020289.
Texte intégralRésumé :
A multiple quantum-well semiconductor saturable absorber mirror (MQW-SESAM) structure has been investigated by femtosecond pump-probe laser spectroscopy at a central wavelength of around 1050 nm. Coherent acoustic phonons are generated and detected over a wide frequency range from ~15 GHz to ~800 GHz. In the optical absorption region, i.e., in the multiple quantum wells (In0.27Ga0.73As), acoustic frequency combs centered at ~365 GHz, with a comb spacing of ~33 GHz, are generated. Most importantly, in the transparent region, i.e., in the distributed Bragg reflector, which is formed by a non-doped long-period semiconductor GaAs/Al0.95Ga0.05As superlattice, the mini-Brillouin-zone center, as well as zone-edge acoustic modes, are observed. The mini-zone-center modes with a fundamental frequency of 32 GHz can be attributed to the spatial modulation of the pump optical interference field with a period very close to that of the distributed Bragg reflector, in combination with the periodic spatial modulation of the electrostriction coefficient in the distributed Bragg reflector. The excitation of mini-zone-edge modes is attributed to the stimulated subharmonic decay of the fundamental center modes. Their subsequent back-folding to the mini-Brillouin-zone center makes them Raman active for the probe light.
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Xu, Guiyun, Shuo Hu, Xiaoguang Zhang, Jiazhou Zhu, Huipeng Zheng et Hongxin Wang. « Dynamic Analysis of Impact Model of Slipping Tramcar Prevention Equipment Based on an Energy Absorber ». Shock and Vibration 2016 (2016) : 1–10. http://dx.doi.org/10.1155/2016/6961272.
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The protection equipment of slipping tramcar in inclined shaft is the important safety equipment to ensure safety production in mine transportation and equipment. The Slipping Tramcar Prevention Equipment is mainly composed of an intercepting door and a buffering system, in which an energy absorber is the key component. The braking dynamic model of the energy absorber is studied by establishing a Lagrange equation and simulating the braking progress by the software of Simulink. The braking simulation distances curves of the energy absorber are obtained under the different initial conditions of tramcar mass and velocity, which shows that the tramcar velocity and mass both have a significant influence on the braking distance. The analysis on variance and range is developed for further comparison on the two key factors implying that tramcar mass is of the most great importance. Moreover, a braking distance formula is built based on the analysis results. On the other hand, field experiments are conducted in Qishan Mine, and experiment results show that the maximum error between the braking distance formula value and the experiment value is 11.98%, and the minimum error is 2.72%. The experimental results are consistent with the theoretical results.
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Saghir, M. Z. « Forced Convection of Nanofluid-Microencapsulated Phase Change Material Mixtures in Mini-Channels : Importance of the Mini-Channel Height ». Journal of Nanofluids 12, no 1 (1 février 2023) : 136–46. http://dx.doi.org/10.1166/jon.2023.1918.
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Energy storage and heat enhancement are the main focus of many projects in the industry. Phase change material is receiving a lot of interest in the energy sector. In particular, storing energy for later use or heat extraction has been the focus of many types of research in this field. Nanofluid and microencapsulated phase change material (MEPCM) flow is an exciting field, mainly when the mixture fluid circulates in mini channels. Many applications, including cooling surfaces, have been investigated. This paper examines how to store energy without using extra space for a particular design. Four different fluids are circulating in mini-channels which are distilled water, 0.5%vol Al2O3 in water, 0.5% Al2O3 +4% MEPCM/water, and 0.5% Al2O3 +20% MEPCM/water. The flow is assumed laminar and steady-state. Results revealed that the amount of energy absorbed when using 0.5% Al2O3 +20% MEPCM/water mixture exceeds 0.5%vol Al2O3 in the water mixture. By varying the mini-channels heights, maintaining constant test volume of the cavity, it was found that the flow in the minichannels and above the mini-channels exhibit the more extensive heat removal capacity. This occurs when the mini-channels height occupies half the test cavity height corresponding to an aspect ratio equal to 6. Among the four fluids under investigation, 0.5% Al2O3 +20% MEPCM/water is the most effective fluid for heat removal and energy storage.
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Huang, Xuchao, Enmao Wang, Gang Wang et Jiuyuan Fan. « Prevention and Control of Hydrogen Sulphide Accidents in Mining Extremely Thick Coal Seam : A Case Study in Wudong Coal Mine ». Geofluids 2021 (7 janvier 2021) : 1–14. http://dx.doi.org/10.1155/2021/8885949.
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Hydrogen sulphide is a toxic gas often present in coal seams and seriously threatens the lives and health of underground workers in coal mines. In this study, we theoretically modelled hydrogen sulphide generation in extremely thick underground coal mines with the +575 level #45 coal seam of Wudong Coal Mine as an example and obtained the on-site hydrogen sulphide emission pattern and spatial distribution features by combining field measurements and computational fluid dynamics simulation. The results showed that hydrogen sulphide mainly exists in the coal porous system in an adsorbed state. Because hydrogen sulphide has a molecular weight greater than the average molecular weight of air molecules, its concentration decreases with the increase of altitude to the bottom plate. When mining the upper stratified coal stratum, it diffuses widely in the working space; while when mining the lower coal stratum, it mainly concentrates at the bottom of the working face. Based on these analyses, on-site treatments were carried out using mixtures with different concentrations of sodium carbonate and sodium bicarbonate. In addition, different combinations of catalysts as well as type A and type B wetting agents were also tested. Eventually, a neutral KXL-I absorbent was developed, and the process of preinjecting absorbent and spraying absorbent was designed. The results showed that the newly developed KXL-I absorbent has high hydrogen sulphide absorption ability and is suitable for use as an absorbent in Wudong Coal Mine; preinjecting and spraying the absorbent can effectively prevent hydrogen sulphide disasters in the +575 level #45 coal seam in Wudong Coal Mine with the optimal final concentration of 0.9% and the absorption rate of 87% at the shearer of 66.6% at the support. Overall, our study provides valuable information for the prevention and control of hydrogen sulphide disasters in coal mines.
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Hadi, Fazal, et Tariq Aziz. « A Mini Review on Lead (Pb) Toxicity in Plants ». Journal of Biology and Life Science 6, no 2 (11 avril 2015) : 91. http://dx.doi.org/10.5296/jbls.v6i2.7152.
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Contamination of soil by various heavy metals is increasing day by day by different activities, such as industrialization and urbanization. Lead (Pb) is one of the potential heavy metal that is neither essential element nor has any role in the process of cell metabolism but it is easily absorbed and accumulated in different parts of a plant. The Pb uptake is mainly regulated by PH, particle size, and cation exchange capacity of the soil, root exudation and by different other physical and chemical parameters. The high concentration of Pb can cause a number of toxic symptoms in plants that may be retardation in growth (Stunted growth), negative affect on photosynthesis (chlorosis), blackening of roots and different other symptoms. Lead (Pb) has the ability to inhibit photosynthesis, disturb mineral nutrition and water balance, changes hormonal status and affects membrane structure and permeability. This review describes different morphological, physiological and biochemical effects of Lead (Pb) toxicity in plants.
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Jin, Mei Hua. « Design and Construction of Solar Absorption Refrigerator Using Organic Compound (R134a and Tetraethelene Glycol Dimethyl Ether) ». Applied Mechanics and Materials 716-717 (décembre 2014) : 799–804. http://dx.doi.org/10.4028/www.scientific.net/amm.716-717.799.
Texte intégralRésumé :
Absorption refrigerator is not a new concept. It provides advantages of being silent, of having no compressor, which also makes it lasting a long life cycle. Particularly, it can utilize low level waste energy. In this contribution, a 2-fluid aqua-ammonia prototype is analysed and an overall design and construction procedure of a mini-type, 3-fluid absorption refrigerator is given, with working fluids of organic compounds (R134a as refrigerant and Tetraethelene Glycol Dimethyl Ether as absorbent) and a pressure balancing gas. The aim of this project is to develop a potential mini-type cooling system for rural areas, where electricity is scarce or non-existed. The experiments showed the combination of R134a and TEG.DEM for mini-type solar absorption refrigeration is theoretically realisable; To have an ideal performance, except of interfusion of non-condensable gas and impermeability of the system, the filling methods, vacuum drawing state as well as the stability of input power are all crucial influence factors.
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Kim, Seong-Hun, Shin-Jae Lee, Il-Sik Cho, Seong-Kyun Kim et Tae-Woo Kim. « Rotational Resistance of Surface-Treated Mini-Implants ». Angle Orthodontist 79, no 5 (1 septembre 2009) : 899–907. http://dx.doi.org/10.2319/090608-466.1.
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Abstract Objective: To test the hypothesis that there is no difference in the stability and resistance to rotational moments of early loaded sandblasted and acid-etched (SLA) mini-implants and those of machined-surface implants of the same size and shape. Materials and Methods: A randomized complete block design was used in 12 skeletally mature male beagle dogs. Ninety-six orthodontic mini-implants were tested. Two types of implants were used: some had SLA surface treatment and some had machined surfaces without coating. After 3 weeks of healing, rotational moments of 150 g were applied. The success rates, maximum torque values, angular momentum, and total energy absorbed by the bone were compared. All values were subjected to mixed-model analysis to evaluate the influence of surface treatment, rotational force direction, and site of implantation. Results: The maximum insertion torque and angular momentum of SLA implants were significantly lower than those of machined implants (P = .034, P = .039). The SLA implants had a significantly higher value for total removal energy than the machined implants (P = .046). However, there were no significant differences in total insertion energy, maximum removal torque, and removal angular momentum between the 2 groups. There was no significant difference between clockwise and counterclockwise rotation in all measurements. Conclusion: SLA mini-implants showed relatively lower insertion torque value and angular momentum and higher total energy during removal than the machined implants, suggesting osseointegration of the SLA mini-implant after insertion.
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Patil, Yash, Om Mali, Parth Mahajan, Harsh Raut et Pranit Mehata. « Power Generation by Shock Absorber ». International Journal for Research in Applied Science and Engineering Technology 11, no 4 (30 avril 2023) : 2923–28. http://dx.doi.org/10.22214/ijraset.2023.50768.
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Abstract: In a country like India, two-wheeler vehicles are predominant over four wheelers. According to data taken from internet, around 20 million two wheelers were sold in 2017/18, as compared to 4 million four wheelers. And this demand keeps on increasing in India. Keeping this mind, a huge potential of energy is being wasted every day. This project is one of the methods to harvest those wasted energy. That’s why this project is under energy recovery. All the major advancements and break through has been done mostly on four wheelers. To name some energy recovery mechanisms, regenerative brakes, regenerative shocks, MGU-H, MGU-K. Even the companies like AUDI and BMW have started launching commercial vehicles which come with energy recovery systems. The main purpose of the dampers is to keep the tires in contact with the ground all the time. Other functions include to absorb the vibrations produced due to irregularities of the surface. This prototype aims to convert these vibrational energies into electricity which otherwise would have been wasted. In a way it can be called Regenerative dampers, which is completely mechanical in nature. This prototype uses a rack and pinion arrangement to convert the reciprocating motion of the bike front fork into a linear motion. The motor is coupled to a DC generator which produces electricity. Our main focus is on two wheelers so, the energy stored can be used to increase the engine efficiency as extra load on alternator is reduced. The aim for this prototype is to produce a current of 0.3A and 12 V (DC), which would be sufficient to charge the batteries and run other auxiliary system of a motorcycle.
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Strand, Sven-Erik, et Margareta Strandh. « Parameters to consider for measurements of absorbed doses in vivo with mini-thermoluminescent dosimeters ». Cancer 73, S3 (1 février 1994) : 985–88. http://dx.doi.org/10.1002/1097-0142(19940201)73:3+<985 ::aid-cncr2820731335>3.0.co;2-8.
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Sun, Yunfei, Tong Li, Lan Lan, Jiahua Chen, Wanqian Zhu, Song Xue et Limin Jin. « A Mini-Review on the Thermal Fatigue Properties of Copper Materials Applied at the Front-End of Synchrotron Radiation Facilities ». Entropy 25, no 5 (26 avril 2023) : 714. http://dx.doi.org/10.3390/e25050714.
Texte intégralRésumé :
Oxygen-free high-conductivity copper (OFHC), chromium-zirconium copper (CuCrZr), and Glidcop® AL-15 are widely used in the high heat load absorber elements at the front end of synchrotron radiation facilities. It is necessary to choose the most suitable material according to the actual engineering conditions (such as the specific heat load, material performance, and costs). In the long-term service period, the absorber elements have to bear hundreds or kilowatts of high heat load and its “load-unload” cyclic loading mode. Therefore, the thermal fatigue and thermal creep properties of the materials are critical and have been extensively studied. In this paper, based on the published pieces of the literature, the thermal fatigue theory, experimental principles, methods, test standards, test types of equipment, and key indicators of the thermal fatigue performance of typical copper metal materials used in the front end of synchrotrons radiation Facilities are reviewed, as well as the relevant studies carried out by the well-known synchrotron radiation institutions. In particular, the fatigue failure criteria for these materials and some effective methods for improving the thermal fatigue resistance performance of the high-heat load components are also presented.
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Ho, Chii-Dong, Luke Chen, Jr-Wei Tu, Yu-Chen Lin, Jun-Wei Lim et Zheng-Zhong Chen. « Investigation of CO2 Absorption Rate in Gas/Liquid Membrane Contactors with Inserting 3D Printing Mini-Channel Turbulence Promoters ». Membranes 13, no 12 (4 décembre 2023) : 899. http://dx.doi.org/10.3390/membranes13120899.
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The CO2 absorption by Monoethanolamine (MEA) solutions as chemical absorption was conducted in the membrane gas absorption module with inserting 3D mini-channel turbulence promoters of the present work. A mathematical modeling of CO2 absorption flux was analyzed by using the chemical absorption theory based on mass-transfer resistances in series. The membrane absorption module with embedding 3D mini-channel turbulence promoters in the current study indicated that the CO2 absorption rate improvement is achieved due to the diminishing concentration polarization effect nearby the membrane surfaces. A simplified regression equation of the average Sherwood number was correlated to express the enhanced mass-transfer coefficient of the CO2 absorption. The experimental results and theoretical predictions showed that the absorption flux improvement was significantly improved with implementing 3D mini-channel turbulence promoters. The experimental results of CO2 absorption fluxes were performed in good agreement with the theoretical predictions in aqueous MEA solutions. A further absorption flux enhancement up to 30.56% was accomplished as compared to the results in the previous work, which the module was inserted the promoter without mini channels. The influences of the MEA absorbent flow rates and inlet CO2 concentrations on the absorption flux and absorption flux improvement are also illustrated under both concurrent- and countercurrent-flow operations.
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Bellay, Jacques-Yves. « Kafka ou la littérature de l’impossible ». Esprit Juin, no 6 (6 juin 2024) : 122–28. http://dx.doi.org/10.3917/espri.2406.0122.
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À l’occasion du centenaire de sa mort, une nouvelle édition de ses œuvres complètes dans la Pléiade, la biographie monumentale de Reiner Stach au Cherche-Midi et le roman de Laurent Seksik chez Gallimard révèlent comment ce Juif tchèque de langue allemande a su absorber le négatif de son époque.
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Hidayat, Cahayahati, Arnita et Saiful Jamaan. « Grid Study of Mini Hydro Power Plant (MHPP) of Palangai Hulu 2x4,9 MW South Pesisir ». MATEC Web of Conferences 248 (2018) : 02003. http://dx.doi.org/10.1051/matecconf/201824802003.
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This paper presents a gridd study of Mini Hydro Power Generation (MHPP) of Palangai Hulu, 2 x 4.9 MW. It is owned by PT. Dempo Sumber Energi (DSE) located at Palangai of South Pesisir Regency. The objective is to fulfill the legal aspects, technical aspects and economic aspects to develop of MHPP. The legal aspect is one of the requirements that must be fulfilled prior to the signing of Power Purchase Agreement (PPA) between DSE and State Electricity Company that called PLN. Technical aspect is to analyze the operational impact of the distribution system after MHPP connecting to the PLN distribution system, while the economic aspect is to analyze how much result energy of MHPP can be absorbed by PLN. Uultimately, it is described the financial feasibility of MHPP. The result is, legal aspect of development of MHPP of Palangai Hulu feasible to be continued to next process to sign contract of PPA. Technically, there is no negative impact of operating the PLN distribution system after the MHPP is connected to the PLN Rayon Balai Selasa system that analyzes using ETAP. Point of Connection (POC) as the selling point of electrical energy by DSE to the most economical PLN is on substation circuit of Balai Selasa. The energy production of MHPP Palangai Hulu can be absorbed 96.4% starting in 2018. The cost of POC is Rp. 11,577,000,000.
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Wardani, A. R. D., S. Octarya, A. Agus et D. H. V. Paradhipta. « The Effect of Absorbent Level and Inoculants on Chemical Composition and Fermentation Characteristics of Fermented Poultry Manure as an Unconventional Feed Ingredient ». IOP Conference Series : Earth and Environmental Science 1360, no 1 (1 juin 2024) : 012030. http://dx.doi.org/10.1088/1755-1315/1360/1/012030.
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Abstract The aim of the present study was to investigate the effect of absorbent level and microbial inoculant on chemical compositions and fermentation characteristics of fermented poultry manure (FPM). In the first trial, the FPM was fermented using two levels of cassava solid waste as absorbent, consisted of 10% (AL10) and 30% (AL30). The best absorbent level to improve the quality of FPM was continued in the second trial. In the second trial, FPM was fermented using inoculant treatments following without inoculants (CON), Lactobacillus plantarum (LP) and multi-purpose microbes (MP). All fermentation was conducted for 14 d in 4 kg mini-silo with quadruplicate. In the first trial, AL30 had higher levels of dry matter and crude fiber but lower levels of crude protein, ether extract, and butyric acid content compared to AL10 (P<0.05). In the second trial, CON presented higher levels of dry matter, crude protein, and crude fiber, but lower levels of ether extract, nitrogen-free extract, pH, ammonia, and butyric acid compared to LP and MP (P<0.05). In conclusion, the present study found that FPM without inoculant at the 30% absorbent level resulted in higher nutrient composition and better fermentation characteristics compared to other treatments.
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Jeong, Cheol-Ho. « Guideline for Adopting the Local Reaction Assumption for Porous Absorbers in Terms of Random Incidence Absorption Coefficients ». Acta Acustica united with Acustica 97, no 5 (1 septembre 2011) : 779–90. http://dx.doi.org/10.3813/aaa.918458.
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Room surfaces have been extensively modeled as locally reacting in room acoustic predictions although such modeling could yield significant errors under certain conditions. Therefore, this study aims to propose a guideline for adopting the local reaction assumption by comparing predicted random incidence acoustical characteristics of typical building elements made of porous materials assuming extended and local reaction. For each surface reaction, five well-established wave propagation models, the Delany-Bazley, Miki, Beranek, Allard-Champoux, and Biot model, are employed. Effects of the flow resistivity and the absorber thickness on the difference between the two surface reaction models are examined and discussed. For a porous absorber backed by a rigid surface, the assumption of local reaction always underestimates the random incidence absorption coefficient and the local reaction models give errors of less than 10% if the thickness exceeds 120 mm for a flow resistivity of 5000 Nm–4s. As the flow resistivity doubles, a decrease in the required thickness by 25 mm is observed to achieve the same amount of error. For an absorber backed by an air gap, the thickness ratio between the material and air cavity is important, since the thicker the cavity, the more extendedly reacting the absorber. If the absorber thickness is approximately 40% of the cavity depth, the local reaction models give errors below 10% even for a low flow resistivity case.
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Jung, Hyen-Cheol, et Weoncheol Koo. « An Experimental Study on Wave Absorber Performance of Combined Punching Plate in a Two-Dimensional Mini Wave Tank ». Journal of Ocean Engineering and Technology 35, no 2 (30 avril 2021) : 113–20. http://dx.doi.org/10.26748/ksoe.2021.006.
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Lyne, Raphael. « Shakespeare and the wandering mind ». Journal of the British Academy 8 (2020) : 01–28. http://dx.doi.org/10.5871/jba/008.001.
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Cognitive scientists are beginning to explore the important work our minds do when attention wanes. In particular, it seems that orientation of the individual in relation to past, present, and future may be developed and maintained during periods of distraction. Shakespeare works with the potential for productive mind-wandering in characters and in audiences. In Henry V, they and we think beyond present business into the ideologies and costs of the underlying plans and possibilities. The King himself embodies the interaction of wandering and selfhood. In Much Ado About Nothing the friends and audience of Beatrice and Benedick may not be fully absorbed by their witty exchanges; there is another story to be told, in the gaps Shakespeare creates in the action of the play, in which they end up taking their inevitable roles as lovers.
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Ghobadi, Amir, Hodjat Hajian, Murat Gokbayrak, Bayram Butun et Ekmel Ozbay. « Bismuth-based metamaterials : from narrowband reflective color filter to extremely broadband near perfect absorber ». Nanophotonics 8, no 5 (13 mars 2019) : 823–32. http://dx.doi.org/10.1515/nanoph-2018-0217.
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AbstractIn recent years, sub-wavelength metamaterials-based light perfect absorbers have been the subject of many studies. The most frequently utilized absorber configuration is based on nanostructured plasmonic metals. However, two main drawbacks were raised for this design architecture. One is the fabrication complexity and large scale incompatibility of these nano units. The other one is the inherent limitation of these common metals which mostly operate in the visible frequency range. Recently, strong interference effects in lithography-free planar multilayer designs have been proposed as a solution for tackling these drawbacks. In this paper, we reveal the extraordinary potential of bismuth (Bi) metal in achieving light perfect absorption in a planar design through a broad wavelength regime. For this aim, we adopted a modeling approach based on the transfer matrix method (TMM) to find the ideal conditions for light perfect absorption. According to the findings of our modeling and numerical simulations, it was demonstrated that the use of Bi in the metal-insulator-metal-insulator (MIMI) configuration can simultaneously provide two distinct functionalities; a narrow near unity reflection response and an ultra-broadband near perfect absorption. The reflection behavior can be employed to realize additive color filters in the visible range, while the ultra-broadband absorption response of the design can fully harvest solar irradiation in the visible and near infrared (NIR) ranges. The findings of this paper demonstrate the extraordinary potential of Bi metal for the design of deep sub-wavelength optical devices.
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Rośkowicz, Marek, et Piotr Leszczyński. « The Selected Problems of Studies of Aircraft Landing Gear ». Research Works of Air Force Institute of Technology 39, no 1 (1 décembre 2016) : 91–102. http://dx.doi.org/10.1515/afit-2016-0020.
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Abstract The article portrays the results of experimental studies conducted in the field of static strength test of main landing gear of lightweight aircraft as well as in the area of establishing the pneumatic tyre characteristics of main landing gear. The studies were carried out in compliance with methodologies of performing studies for the purposes of solutions implemented in aviation structures. It was stated that static strength tests of landing gear should not be done with the use of shock absorbers, due to the fact that this element, distinguished by high viscoelastic properties, by being statically loaded, is subject to displacements that do not occur during normal operation of the aircraft. Excessive displacements of shock absorber result in the load distribution in other landing gear elements being incompatible with project assumptions, which in turn leads to this strength test being interrupted, bearing in mind significantly lower loads than anticipated. It was also concluded that in order to determine pneumatic tyre characteristics it is not necessary to carry out tests on the whole landing gear strut, because the results obtained in the compression test of the wheel itself with pneumatic tyre are identical as the results acquired during tests conducted in accordance with methodology. Test preparation process with the use of the wheel itself and its realization is less time-consuming, less expensive and does not entail the necessity to build complex test stands.
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Sathish, Dhandapani, M. Veeramanikandan, R. Thirunavukkarasu, R. Tamilselvan et T. Karthickmunisamy. « Thermal Performance on Portable Mini Solar Pond Using NaCl and Coal Cinder ». Applied Mechanics and Materials 877 (février 2018) : 430–35. http://dx.doi.org/10.4028/www.scientific.net/amm.877.430.
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Solar energy is being used in many ways, but the easiest to trap solar energy is solar pond. Solar Ponds absorb the solar energy and the absorbed solar energy will be taken away by a streaming fluid. A non-convective solar pond has been constructed to investigate the temperature variations of it, in the weather conditions of Pachapalayam, Coimbatore. Solar pond with a surface area of 1.7m2, a depth of 0.5m has been built-up and an inflexible surface is maintained at the bottom using a dark-colored (blackened) HDPE sheet, thermo styrene for capturing the heat in a good amount. Measurement of the temperature at depths of 0.05, 0.1. 0.2, 0.25, 0.3, 0.35, 0.4 0.45, m from the base of the pond and ambient temperature were taken using washer type thermocouples. Solar radiations were taken during a period of 10 days of experimentation using a solar power meter. In this experimental work investigated the performance of solar pond with NaCl salt and coal cinder
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Campana, S., A. Miraval Zanon, F. Coti Zelati, D. F. Torres, M. C. Baglio et A. Papitto. « Probing X-ray emission in different modes of PSR J1023+0038 with a radio pulsar scenario ». Astronomy & ; Astrophysics 629 (septembre 2019) : L8. http://dx.doi.org/10.1051/0004-6361/201936312.
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Transitional pulsars provide us with a unique laboratory to study the physics of accretion onto a magnetic neutron star. PSR J1023+0038 (J1023) is the best studied of this class. We investigate the X-ray spectral properties of J1023 in the framework of a working radio pulsar during the active state. We modelled the X-ray spectra in three modes (low, high, and flare) as well as in quiescence, to constrain the emission mechanism and source parameters. The emission model, formed by an assumed pulsar emission (thermal and magnetospheric) plus a shock component, can account for the data only adding a hot dense absorber covering ∼30% of the emitting source in high mode. The covering fraction is similar in flaring mode, thus excluding total enshrouding, and decreases in the low mode despite large uncertainties. This provides support to the recently advanced idea of a mini-pulsar wind nebula (PWN), where X-ray and optical pulsations arise via synchrotron shock emission in a very close (∼100 km, comparable to a light cylinder), PWN-like region that is associated with this hot absorber. In low mode, this region may expand, pulsations become undetectable, and the covering fraction decreases.
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Reddy, Arun, et Narendar Reddy. « Development of Multiple-Unit Floating Drug Delivery System of Clarithromycin : Formulation, in vitro Dissolution by Modified Dissolution Apparatus, in vivo Radiographic Studies in Human Volunteers ». Drug Research 67, no 07 (27 avril 2017) : 412–18. http://dx.doi.org/10.1055/s-0043-102952.
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AbstractClarithromycin (CM), a broad spectrum macrolide antibiotic used to eradicate H. pylori in peptic ulcer. Clarithromycin (CM) is well absorbed from the gastrointestinal tract, but has a bioavailability of 50% due to rapid biodegradation. The aim of this investigation was to increase the gastric residence time, and to control the drug release of clarithromycin by formulating into multiple unit floating mini-tablets. Floating tablets were prepared by using direct compression method with HPMC K4M and Polyox WSR 1105 as release retarded polymers and sodium bicarbonate as gas generating agent. The prepared mini-tablets were evaluated for thickness, weight variation, friability, hardness, drug content, in vitro buoyancy, swelling studies, in vitro dissolution studies by using modified Rossett-Rice test and in vivo radiographic studies in healthy human volunteers in fasting conditions. DSC analysis revealed that no interaction between drug and excipients. All the physical parameters of the tablets were within the acceptable limits. The optimized formulation (F6) had showed controlled drug release of 99.16±3.22% in 12 h, by zero-order release kinetics, along with floating lag time of 9.5±1.28 s and total floating time of 12±0.14 h. X-ray imaging studies revealed that in vivo gastric residence time of clarithromycin floating mini-tablet in the stomach was about 3.5 h. The results demonstrated that the developed floating mini-tablets of clarithromycin caused significant enhancement in gastric retention time along with sustained effect and increased oral bioavailability.
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Jangra, Mamta, Raj Bhupen, Gobinda Majumder, Kiran Gothe, Mandar Saraf, Nandkishor Parmar, B. Satyanarayana et al. « Qualification study of SiPMs on a large scale for the CMVD Experiment ». Journal of Instrumentation 17, no 07 (1 juillet 2022) : P07019. http://dx.doi.org/10.1088/1748-0221/17/07/p07019.
Texte intégralRésumé :
Abstract A Cosmic Muon Veto (CMV) detector using extruded plastic scintillators is being designed around the mini-Iron Calorimeter (mini-ICAL) detector at the transit campus of the India based Neutrino Observatory, Madurai for the feasibility study of shallow depth underground experiments. The scintillation signals that are produced in the plastic due to muon trajectories are absorbed by wavelength shifting (WLS) fibres. The WLS fibres re-emit photons of longer wavelengths and propagate those to silicon photo-multipliers (SiPMs). The SiPMs detect these photons, producing electronic signals. The CMV detector will use more than 700 scintillators to cover the mini-ICAL detector and will require around 3000 SiPMs. The design goal for the cosmic muon veto efficiency of the CMV is >99.99%. Hence, every SiPM used in the detector needs to be tested and characterised to satisfy the design goal of CMV. A mass testing system was developed for the measurement of gain and choice of the overvoltage (V ov) of each SiPMs using an LED driver. The V ov is obtained by studying the noise rate, the gain of the SiPM. This paper describes the experimental setup used to test the SiPMs characteristics along with detailed studies of those characteristics as a function of temperature.
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Catusso, Leonardo, Arthur De Souza Borges Zuchetti Alves, Lucio Pereira Neves, Ana Paula Perini, Carla De Jesus Santos, Lucas Morato Silveira, João Vinícius Batista Valença, Walmir Belinato et William De Souza Santos. « Evaluation of absorbed doses in Uranium mine workers using Monte Carlo simulation ». Revista Brasileira de Física Médica 18 (5 février 2024) : 751. http://dx.doi.org/10.29384/rbfm.2024.v18.19849001751.
Texte intégralRésumé :
Neste trabalho, foi avaliada a exposição de trabalhadores suscetíveis a materiais radioativos de ocorrência natural (NORMs) presentes nas estruturas de uma mina de urânio. Os cenários de exposição computacional foram modelados utilizando o código de transporte da radiação MCNPX2.7.0 e os trabalhadores foram representados por simuladores antropomórficos adultos de referência da Comissão Internacional de Proteção Radiológica (ICRP). O ambiente representado no estudo foi referente à mina de Cigar Lake, Canadá. O simulador antropomórfico feminino foi mais exposto do que o masculino, devido a sua menor distância entre os órgãos radiossensíveis e a fonte principal (o solo). O fator de conversão para dose efetiva, derivado da média das doses equivalentes dos dois simuladores, foi de 1,2 Sv/Gy, que é superior em 70% do valor recomendado pelo Comitê Científico das Nações Unidas sobre os Efeitos da Radiação Atômica (UNSCEAR).
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Alam, Tabish, Nagesh Babu Balam, Kishor Sitaram Kulkarni, Md Irfanul Haque Siddiqui, Nishant Raj Kapoor, Chandan Swaroop Meena, Ashok Kumar et Raffaello Cozzolino. « Performance Augmentation of the Flat Plate Solar Thermal Collector : A Review ». Energies 14, no 19 (28 septembre 2021) : 6203. http://dx.doi.org/10.3390/en14196203.
Texte intégralRésumé :
The need for hot water in residential buildings requires a significant energy potential. Therefore, an efficient water heating system is important to achieve the goal of saving high-grade energy. The most simple and cheapest solar water heater is a flat plate solar collector (FPSC), which can increase the thermal energy of fluid by absorbing solar radiation. The performance of FPSC is comparatively low due to the dilute nature of solar insolation. Therefore, advancement of FPSC is being undertaken to improve the performance and achieve size reduction. In past, several techniques have been exploited to improve the performance of FPSC, which are presented in the present paper. These techniques include surface modifications, use of nanofluids, solar selective coating, and applications of a mini/macro channel, heat pipe, and vacuum around absorber. Surface modification on the absorber/absorber tube techniques are exploited to transfer the maximum possible solar energy to working fluids by increasing the heat transfer rate. Insertion of wire mesh, coil, and twisted tapes in the flow has great potential to increase the Nusselt number by 460% at the expense of a large pressure drop. Selective coating of Cu0.44 Ti0.44 Mn0.84 helps to absorb up to 97.4% of the incident solar energy, which is more significant. Many nanofluids have been exploited as heat transfer fluids, as they not only increase the performance but also reduce the fluid inventory. So, these techniques play a very prominent role in the performance of FPSC, which are discussed in detail. Summaries of the results are presented and recommendations proposed.
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Fira, Fira Hendri, Eddy Ibrahim et Hilda Zulkifli. « EFFECTIVITY OF Lepironia articulate Retz (Domin.) AS AN ABSORBEND OF HEAVY METALS FE AND MN ACID MINE DRAINAGE ». BIOVALENTIA : Biological Research Journal 9, no 1 (17 juin 2023) : 23–29. http://dx.doi.org/10.24233/biov.9.1.2023.342.
Texte intégralRésumé :
Indonesia is one of the world's largest coal-producing countries. Most coal mining activities are conducted using the open-pit method. A classic problem caused by mining activities is acid mine drainage (AMD). Various conventional methods have been developed to increase the pH of the water and remove heavy metals such as iron (Fe) and manganese (Mn) in acid mine drainage, including chemical precipitation, coagulation, flocculation, microorganisms, adsorption, and passive treatment methods. In this study, a passive treatment method using constructed wetlands with phytoremediation techniques using L. articulate plants was employed. This study aims to analyze the effectiveness of the L. articulate plant in increasing the acidity of water and reducing the levels of Fe and Mn metals dissolved in acid mine drainage. The results of the initial sample analysis of acid mine drainage showed a pH of 2.8. The initial values of Fe met-al concentrations were 0.09 mg/L and Mn 8.10 mg/L. After the phytoremediation process, it was found that L. articulate plants were effective in increasing the pH value and reducing the concentrations of dissolved Fe and Mn metals in acid mine drainage within 20 days. The percentage reduction was 93.33% in the organic reactor and 55.56% in the inorganic reactor for Fe metal concentrations. For Mn metal reduction, the percentages were 38.02% in the organic reactor and 25.80% in the inorganic reactor.