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1
Sakly, M., and G. Lambrinos. "Sublimation de la glace sous convection forcee. Determination du coefficient global de transfert de masse." International Communications in Heat and Mass Transfer 16, no. 5 (September 1989): 633–44. http://dx.doi.org/10.1016/0735-1933(89)90069-9.
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Boczar, J., A. Dorobczynski, and J. Miakotoi. "Modèle de transfert et de diffusion de masse dans un écoulement, en présence de gradients de vitesse et de gradients du coefficient de diffusion turbulente." Revue des sciences de l'eau 5, no. 3 (April 12, 2005): 353–79. http://dx.doi.org/10.7202/705136ar.
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Le travail présente un modèle mathématique conceptuel de transfert et de diffusion de masse destiné à l'étude des migrations d'effluents en rivière. Ce modèle prend en compte l'existence d'écoulements cisaillés ainsi que la présence de gradients de diffusion turbulente. Il permet de calculer les champs de concentrations et les valeurs moyennes de concentration à travers toute section transversale de l'écoulement. La localisation et la taille relative du rejet sont respectées. L'influence des rives sur les processus de dispersion est prise en considération.Pour quantifier l'influence des berges, une relation est établie entre les concentrations calculées en écoulement de largeur infinie et les concentrations en écoulement d'extension limitée. La méthode utilisée est fondée sur l'emploi d'un champ de vitesse et d'un champ de coefficient de diffusion, symétriques par rapport à des lignes riveraines séparant le courant nul d'un courant fictif situé de part et d'autre de ces limites.Les résultats des tests du modèle mathématique, réalisés à l'aide du programme moniteur « Gradient 2 », sont présentés. Dans le cas d'écoulements cisaillés, on a constaté que la valeur moyenne de concentration d'effluent calculée au travers de sections transversales à l'écoulement n'était pas une quantité invariante tout au long de l'écoulement. Un gradient de vitesse négatif induit une augmentation de cette moyenne à mesure que l'on s'éloigne du rejet alors qu'un gradient positif produit l'effet inverse. Un gradient du coefficient de diffusion turbulente détermine un changement du profil de concentration à l'intérieur d'une section transversale donnée, sans en changer cependant la valeur moyenne. Un gradient négatif augmente la valeur maximale de la distribution des concentrations. Un gradient positif fait diminuer la valeur maximale en aplatissant l'allure du profil.Le modèle mathématique a ensuite été vérifié à l'aide d'un modèle physique. Un modèle réduit respectant les similitudes d'écoulement a été bâti. Les gradients de vitesse du fluide et les gradients du coefficient de diffusion étaient provoqués par l'introduction de tirants d'eau non uniformes dans chaque section transversale. Les mesures réalisées ont permis d'estimer les coefficients de diffusion turbulente.
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Hasanov, A. A. "DETERMINATION OF SELECTIVITY AND MASS TRANSFER IN LIQUID-PHASE EXTRACTION FOR BUTYL GLYCOL-WATER-ISOPROPYL ETHER SYSTEM." Azerbaijan Chemical Journal, no. 4 (December 12, 2020): 17–21. http://dx.doi.org/10.32737/0005-2531-2020-4-17-21.
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The problems of phase equilibrium, the equilibrium distribution of a component between phases are considered, and the distribution coefficient is determined in two versions. A formula for determining the selectivity coefficient is obtained, equations relating the compositions of coexisting phases, by equating the activities in these phases, Margules constants are found. Based on the given content of the components, the numerical values of (Margules constant for A component in solvent S) and (Margules constant for S component in solvent A) were found Using the Margules equation for ternary systems, the activity coefficients of components A and B are determined in two phases. The experimentally obtained values of the molar fractions of each of the three components, responsible to different points of the binodal curve, the corresponding activity coefficients of component B, and also calculated on these coefficients of the activity values
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SUGIYAMA, Katsuteru, Hiroki NOGUCHI, Hiroaki TAKEGAMI, Kaoru ONUKI, Akiko KANEKO, and Yutaka ABE. "ICONE19-43281 MEASUREMENT OF MASS TRANSFER COEFFICIENT IN DIRECT CONTACT SULFURIC ACID CONCENTRATION FOR IS PROCESS." Proceedings of the International Conference on Nuclear Engineering (ICONE) 2011.19 (2011): _ICONE1943. http://dx.doi.org/10.1299/jsmeicone.2011.19._icone1943_118.
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Wahyuningsih, Wahyuningsih, and Moh Endy Yulianto. "EKSTRAKSI ASAM LEMAK BEBAS DARI MINYAK NABATI DENGAN METANOL KAJIAN PERPINDAHAN MASSA." Gema Teknologi 16, no. 4 (April 15, 2012): 173. http://dx.doi.org/10.14710/gt.v16i4.4785.
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Wahyuningsih, Moh Endy Yulianto, in this paper explain that extraction of free fatty acids from vegetable oils with methanol performed in batch stirred tank, in a variety of conditions. Variables experiments in liquid-liquid extraction including temperature, solvent ratio and rotational speed stirrer. This study aims to develop a correlation coefficient of mass transfer in extraction of free fatty acids from vegetable oils methanol. Rresearch was conducted in two phases. Was the first stage liquid-liquid extraction experiments in laboratory. Second step is the development of an empirical correlation for the mass transfer coefficients in the form of numbers not berdemensi results showed that the greater the temperature, turn the mixer speed and solvent-feed ratio of the mass transfer koffisien gained greater. Mass transfer coefficient expressed in Sherwood number and correlated against the Reynolds number, Schmitd, (dP / dT) and (L / S), the results obtained: Sh = 4,669 x 10-5 Re 0,462 Sc0,5 (dP/dT)0,308 (L/S)0,187 If used to calculate the mass transfer coefficients, have an average error of 8.79% for the regression line. This equation was developed in the Re number range 3169 to 11 750; numbers Sc 6321 to 9896, (dp / dT) from 0.0007 to 0.0013 and (L / S) of 0.333 to 1. Keywords: nabati oil extraction
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Hosovkyi, Roman, Diana Kindzera, and Volodymyr Atamanyuk. "Diffusive Mass Transfer during Drying of Grinded Sunflower Stalks." Chemistry & Chemical Technology 10, no. 4 (September 15, 2016): 459–63. http://dx.doi.org/10.23939/chcht10.04.459.
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Diffusive mass transfer has been studied during drying of grinded sunflower stalks to produce fuel briquettes. Theoretical aspects of diffusive processes during filtration drying have been analyzed. The process of diffusive mass transfer during drying of grinded sunflower stalks particles of prismatic shape has been mathematically described. The temperature effect on effective diffusion coefficient has been examined.
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Nazari, Ghadir, Hossein Abolghasemi, and Mohamad Esmaieli. "Study of Mass Transfer Coefficient of Cephalexin Adsorption onto Walnut Shell-Based Activated Carbon in a Fixed-Bed Column." Chemistry & Chemical Technology 10, no. 1 (March 15, 2016): 81–86. http://dx.doi.org/10.23939/chcht10.01.081.
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Lívanský, Karel, and Jiří Doucha. "Liquid film mass transfer coefficients KL for O2 and C02 desorption from open thin-layer microalgal cultures into atmosphere." Algological Studies/Archiv für Hydrobiologie, Supplement Volumes 92 (March 19, 1999): 109–32. http://dx.doi.org/10.1127/algol_stud/92/1999/109.
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Sun, J. G., and M. M. Chen. "Measurement of Surface Heat Transfer Due to Particle Impact." Journal of Heat Transfer 117, no. 4 (November 1, 1995): 1028–35. http://dx.doi.org/10.1115/1.2836277.
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Heat transfer coefficients for a surface continuously impacted by a stream of falling particles in air and in helium were measured as functions of particle flux and particle velocity. The purpose was to provide well-controlled data to clarify the mechanisms of heat transfer in particle suspension flows. The particles were spherical glass beads with mean diameters of 0.5, 1.13, and 2.6 mm. The distribution of the particle impact flux on the surface was determined by deconvolution from the measurement of the total solid masses collected at both sides of a movable splitter plate. The particle velocity was calculated from a simple, well-established model. The experimental results showed that in air, the heat transfer coefficient increases approximately linearly with particle impact flux. At high impact fluxes, the heat transfer coefficient decreases with particle impact velocity, and at low impact fluxes, it increases with particle impact velocity. Furthermore, the heat transfer coefficient decreases drastically with the particle size. In helium gas, it was found that at low particle impact fluxes, the difference between the coefficients in helium and in air is small, whereas at high fluxes, the difference becomes large. A length scale, V/n˙dp2, was used to correlate the data. At low particle Reynolds numbers, gas-mediated heat conduction was identified as the dominant particle/surface heat transfer mechanism, whereas at high particle Reynolds numbers, induced gas convection was the dominant mechanism.
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Setyawan, Martomo, Panut Mulyono, Sutijan Sutijan, Yano Surya Pradana, Laras Prasakti, and Arief Budiman. "Effect of Devices and Driving Pressures on Energy Requirements and Mass Transfer Coefficient on Microalgae Lipid Extraction Assisted by Hydrodynamic Cavitation." International Journal of Renewable Energy Development 9, no. 3 (August 24, 2020): 467–73. http://dx.doi.org/10.14710/ijred.2020.26773.
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Previous studies of biodiesel production from microalgae have concluded that microalgal biodiesel is not profitable at an industrial scale due to its excessive energy consumption for lipid extraction. Hydrodynamic cavitation lipid extraction is one of the extraction methods which has lower energy consumption. Thismethod enables a fast extraction rate and low energy consumption for cell disruption. In order to achieve optimum process conditions, several influential parameters, which are cavitation generator geometry and driving pressure, need to be scrutinized. The experimental result showed that the maximum yield was obtained at 5 bar driving pressure. The lowest specific extraction energy was obtained at 4.167 bar driving pressure while using one side concave cavitation generator geometry with the ratio of the reduced cross-sectional area of 0.39. The value of the energy extraction requirement 17.79 kJoule/g lipids is less than the biodiesel heating value, and the value of the volumetric mass transfer coefficient is almost 20 times fold greater than the conventional extraction method, therefore this method is promising to be further developed.
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Lívanský, Karel, and Jiří Doucha. "An estimation method for CO2/O2 photosynthetic rates and for CO/O2 mass transfer coefficients in outdoor algal culture units." Algological Studies/Archiv für Hydrobiologie, Supplement Volumes 74 (September 30, 1994): 125–40. http://dx.doi.org/10.1127/algol_stud/74/1994/125.
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Mardina, Primata, Ajang Gunawan, and Muhammad Imam Nugraha. "PENENTUAN KOEFISIEN TRANSFER MASSA EKSTRAKSI KALIUM DARI ABU BATANG PISANG." Konversi 1, no. 1 (October 1, 2012): 39. http://dx.doi.org/10.20527/k.v1i1.116.
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Abstrak-Kalium sebagai mineral alam bisa didapatkan dari batang pisang dengan cara ekstraksi padat-cair pada abu batang pisang menggunakan pelarut methanol. Penelitian ini bertujuan untuk mengetahui pengaruh suhu pada proses ekstraksi kalium dari abu batang pisang koefisien transfer massa proses tersebut. Proses ekstraksi ini dilakukan secara batch pada labu leher tiga yang dilengkapi dengan motor pengaduk, pendingin balik, termometer dan media pemanas. Abu batang pisang sebanyak 25 gram dan metanol 250 mL dimasukkan ke dalam labu leher tiga sebagai sampel. Ekstraksi dimulai dengan memanaskan sampel sampai suhu yang diinginkan, yaitu 30oC, 45 oC dan 60 oC, kemudian motor pengaduk dijalankan pada kecepatan yang telah ditentukan. Sampel diambil dalam selang waktu tertentu 0, 15, 30, 60, 120 180 dan 240 menit. Dari proses ekstraksi kalium dapat diketahui koefisien transfer massa. Hasil penelitian menunjukkan bahwa koefisien transfer massa semakin besar dengan semakin tinggi suhu operasi. Nilai koefisien transfer massa terbesar adalah 0,0235/menit pada suhu 60oC. Hubungan antara koefisien transfer massa dengan variabel-variabel yang mempengaruhinya dapat dinyatakan dengan persamaan dalam bentuk kelompok tak berdimensi sebagai berikut: Dengan ralat rata-rata 6,56 % Keywords: Ekstraksi, kalium, abu batang pisang, Abstract-Potassium is the one of chemical compounds which can be extracted from ash of pseudo stem of banana by methanol solid-liquid extraction method. The experiment investigated the effect of temperature on mass transfer coefficient of potassium extraction process from ash of banana’s pseudo stem. This experiment conducted in a three necks flask which equipped with mechanical stirrer, condenser, thermometer and heating mantle. The sample was heated to desired temperature, 30oC, 45 oC and 60 oC. and maintained constant while reaction time. The reaction was timed as soon as the mechanical stirrer was turned on. Samples were drawn at specified time interval 0, 15, 30, 60, 120, 180 and 240 minutes. The result showed increasing temperature increased mass-transfer coefficient. The highest value of mass-transfer coefficient was 0,0235 /minute at 60oC.The correlation between mass transfer coefficient and investigated variables is shown in the dimensionless equation below: The average error is 6.56 % Keywords: Extraction, potassium, ash of banana’s pseudo stem.
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Putrawan, I. Dewa Gede Arsa, Rizkyanto Nugroho, and Reza Anggara. "Ekstraksi Asam Lemak Bebas dari Minyak Dedak Padi Menggunakan Etanol-Air dalam Tangki Pengaduk." Reaktor 17, no. 3 (October 3, 2017): 166. http://dx.doi.org/10.14710/reaktor.17.3.166-176.
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Abstract EXTRACTION OF FREE FATTY ACID FROM RICE BRAN OIL USING ETHANOL-WATER IN A STIRRED TANK. This research was aimed to study the extraction of free fatty acid (FFA) from rice bran oil (RBO) in a stirred tank. Fatty acid mixtures derived from RBO were used as FFAs and aqueous ethanol as solvent. First, the distribution coefficients of FFAs were measured through equilibrium experiments. The experiments were carried at 25°C with ethanol concentration in the solvent and FFA concentration in RBO in the ranges of 85-95%-w and 10-30%-w, respectively. In general, the distribution coefficient of FFA was linearly dependent on ethanol concentration. A constant distribution coefficient of 0.9 for FFA RBO, however, is a fairly acceptable assumption with a deviation range of 20-30%. In addition, FFA mixtures in RBO could be represented by a pseudo-component. Extraction experiments were proposed to measure the mass transfer coefficient of FFA, with experimental variations including solvent to feed ratio, ethanol concentration in the solvent, stirring rate, and FFA concentration in RBO. The mass transfer coefficient was in the range of (0.5-1.9)10-3 kg·m-2·s-1. Increasing solvent to feed ratio, ethanol concentration in the solvent, stirring rate, or FFA concentration in RBO increased mass transfer coefficient. The mass transfer coefficient data could be correlated well using the dimensionless equation of Skelland-Xien. Keywords: free fatty acid; extraction; rice bran oil; stirred tank Abstract Penelitian ini diarahkan untuk mengkaji ekstraksi asam lemak bebas (ALB) dari minyak dedak padi (MDP) dalam sebuah tangki pengaduk. Campuran asam lemak yang diturunkan dari MDP (ALB MDP) digunakan sebagai ALB dan etanol-air sebagai pelarut. Pertama, koefisien distribusi ALB diukur melalui percobaan kesetimbangan. Percobaan dilakukan pada temperatur 25°C dengan konsentrasi etanol dalam pelarut dan konsentrasi ALB dalam MDP masing-masing pada rentang 85-95%-berat dan 10-30%-berat. Secara umum, koefisien distribusi ALB terhubungkan secara linier dengan konsentrasi etanol. Walaupun demikian, koefisien distribusi ALB MDP tetap sebesar 0,9 merupakan asumsi yang cukup dapat diterima dengan rentang galat 20-30%. Tambahan pula, ALB MDP dapat digambarkan sebagai komponen semu. Percobaan ekstraksi diarahkan untuk mengukur koefisien perpindahan massa ALB, dengan variasi percobaan meliputi rasio pelarut terhadap umpan, konsentrasi etanol dalam pelarut, laju putaran pengaduk, dan konsentrasi ALB dalam MDP. Koefisien perpindahan massa yang diperoleh berada pada rentang (0,5-1,9)10-3 kg·m-2·s-1. Kenaikan rasio pelarut terhadap umpan, konsentrasi etanol dalam pelarut, laju putaran pengaduk, atau konsentrasi ALB dalam MDP meningkatkan koefisien perpindahan ALB. Data koefisien perpindahan massa dapat dikorelasikan dengan baik menggunakan persamaan tak berdimensi dari Skelland-Xien. Kata kunci: asam lemak bebas; ekstraksi; minyak dedak padi; tangki pengaduk
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Aliwarga, Lienda. "Investigating Mass Transfer Phenomena in Batch Solvent Extraction of Rice Bran Oil." Reaktor 19, no. 1 (May 10, 2019): 1–10. http://dx.doi.org/10.14710/reaktor.19.1.1-10.
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In this study, we will point out the correlation of critical parameters in designing scale-up of process equipment for commercial rice bran oil extraction with different types of rice paddy, solvent, and physicochemical condition. Advantageously, this research was also intended to enhance the discoveries of novel sustainable production method for resilient agro-based food, energy, and chemical industries. In our experiment, the extraction of rice bran oil was organised in a batch agitated vessel and showed a profile of first order system. The most important factors which profoundly contributed towards the yield of rice bran oil from Saigon I and PadiBesar variety are temperature (T), impeller speed (N), ratio of bran to solvent (s/L), and ratio of impeller’s height-off bottom to tank diameter (h/d). For the mass transfer constant and the rate of extraction as consequence, factors that significantly influenced the correlation were temperature (T), impeller speed (N), ratio of impeller diameter to tank diameter (d/D), and ratio of impeller’s height-off bottom to tank diameter (h/d). For the dimensionless yield, generalised equation is provided with coefficient of determination 0.95, while that of the mass transfer equals to 0.63, reflecting the yield correlation to be more accurate in predicting further experimental results. These correlations are furthermore unique for different rice varieties, of which in this case belongs to Saigon I. Application for other rice species is relevant as by inserting additional correction factor which also exemplified in this research for PadiBesar. Keywords: rice bran oil; batch extraction; storage time; mass transfer, rate, yield
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Mirwan, Agus. "KEBERLAKUAN MODEL HB-GFT SISTEM n-HEKSANA – MEK – AIR PADA EKSTRAKSI CAIR-CAIR KOLOM ISIAN." Konversi 2, no. 1 (April 1, 2013): 32. http://dx.doi.org/10.20527/k.v2i1.126.
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Ekstraksi cair-cair dalam kolom isian merupakan proses pemisahan fasa cair yang memanfaatkan perbedaan kelarutan suatu zat. Tipe ekstraksi ini termasuk kedalam tipe ekstraksi kolom vertikal tanpa berpengaduk (unagitated) selain kolom semprot (spray) dan kolom pelat. Operasi ekstraksi cair-cair yang baik sangat dipengaruhi oleh karakteristik perpindahan zat terlarut (solute). Karakteristik ini dapat dikuantifikasikan dengan suatu nilai yang disebut dengan koefisien perpindahan massa. Koefisien perpindahan massa ini sangat penting untuk diketahui dalam perancangan kolom ekstraksi cair-cair dan nilainya dapat dicari dengan menggunakan model-model estimasi koefisien perpindahan massa baik di fasa dispersi maupun fasa kontinyu. Penelitian ini bertujuan untuk membuktikan keberlakuan model Handloss-Baros – Garner-Foord-Tayeban (HB-GFT) pada proses ekstraksi cair-cair menggunakan prototipe kolom transparan dan jenis isian berupa bola-bola kecil dengan variasi laju alir fasa kontinyu dan fasa dispersi pada rentang tetesan bersirkulasi (Re = 10 – 200). Dari penelitian ini didapatkan bahwa jenis isian, ukuran tetesan, dan laju alir fasa kedua (dispersi dan kontinyu) memberikan pengaruh yang cukup signifikan terhadap proses perpindahan massa yang dinyatakan dengan koefisien perpindahan massa keseluruhan (KOD). Data laju alir dan komposisi masing-masing fasa di aliran masuk dan keluar kolom dianalisis dengan menggunakan alat kromatografi gas (GC) yang ditunjukan dengan makin besar laju alir fasa dispersi (Qd), koefisien perpindahan massa keseluruhan (KOD) makin kecil. Hal ini disebabkan bahwa ukuran diameter tetesan disepanjang kolom isian dianggap sama. Dan keberlakuan model HB-GFT untuk dinamika tetesan sirkulasi internal (170<Re<200) merupakan kombinasi terbaik dalam penentuan KOD dengan standar deviasi sebesar 3,2%. Keywords: ekstraksi, kolom isian, perpindahan massa. Liquid-liquid extraction in packed column is a process of liquid phase separation in which a liquid solution (the feed) is contacted with an immiscible or nearly immiscible liquid (solvent). This type of extraction is a kind of vertical column extraction type without agitator (unagitated column) besides spray column and plate column. Good operation of liquid-liquid extraction hardly influenced by solute transfer characteristic. This characteristic can be quantification with a value so-called with mass transfer coefficient. Mass transfer coefficient is importance in order to be known in scheme of liquid-liquid extraction column and the values can be searched by using estimation models of mass transfer coefficient either in dispersion phase and also continue phase.The aim of this research is to prove model applying Handloss-Baros - Garner-Foord-Tayeban (HB-GFT) at liquid-liquid extraction process using transparent column prototype and packing type of small sphere with various of flow rate continue phase and dispersion phase at circulation drop spread (Re = 10 - 200). From this research got that packing type, droplet size, and flow rate phase (dispersion and continue) gives influence that is enough significant to mass transfer process that expressed with overall mass transfer coefficient (KOD). Flow rate and composition each phase in inlet and outlet column data are analyzed by using gas chromatography equipment (GC) that showed more and more big dispersion phase (Qd) flow rate, mass transfer coefficient (KOD) more and more small. This caused that drop diameter measure along the length of packing column assumed to be same. And model applying HB-GFT for internal circulation drop dynamics (170<Re<200) is best combination in determination of KOD with deviation standard equal to 3,2%. Keywords: extraction, packing column, mass transfer
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Bohne, Tobias, Tim Frerich, Jörg Jendrny, Jan-Patrick Jürgens, and Vasily Ploshikhin. "Simulation and validation of air flow and heat transfer in an autoclave process for definition of thermal boundary conditions during curing of composite parts." Journal of Composite Materials 52, no. 12 (October 27, 2017): 1677–87. http://dx.doi.org/10.1177/0021998317729210.
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Aerospace carbon fibre-reinforced components are cured under high pressure (7 bar) and temperature in an autoclave. As in an industrial environment, the loading of an autoclave usually changes from cycle to cycle causing different thermal masses and airflow pattern which leads to an inhomogeneous temperature distribution inside the carbon fiber-reinforced plastic part. Finally, the overall process can be delayed and the part quality can be compromised. In this paper, the heat transfer in a small laboratory autoclave has been investigated using calorimeter measurements and a fluid dynamic model. A complex turbulent flow pattern with locally varying heat transfer coefficient has been observed. Especially, the pressure and the inlet fluid velocity have been identified as sensitive process parameters. Further finite element simulations with adjusted boundary conditions provide accurate results of the curing process inside of the components for selective process control. The heat transfer coefficient has been found to be almost stationary during the observed constant pressure autoclave process allowing a separated investigation of the heat transfer coefficient and the curing of the components. The presented method promises therefore a detailed observation of the autoclave process with reduced computational effort.
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Gonçalves Cremonez, Victor, Dile Pontarolo Stremel, Jorge Luís Monteiro de Matos, and Ricardo Jorge Klitzke. "ESTIMATIVA DO COEFICIENTE DE TRANSFERÊNCIA DE MASSA E VALIDAÇÃO DE UM MODELO DINÂMICO NÃO LINEAR PARA UM SECADOR SOLAR." ENERGIA NA AGRICULTURA 35, no. 3 (September 29, 2020): 404–14. http://dx.doi.org/10.17224/energagric.2020v35n3p404-414.
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ESTIMATIVA DO COEFICIENTE DE TRANSFERÊNCIA DE MASSA E VALIDAÇÃO DE UM MODELO DINÂMICO NÃO LINEAR PARA UM SECADOR SOLAR
VICTOR GONÇALVES CREMONEZ1, DILE PONTAROLO STREMEL2, JORGE LUIS MONTEIRO DE MATOS3, RICARDO JORGE KLITZKE4
1 Departamento de Engenharia e Tecnologia Florestal, Universidade Federal do Paraná, Avenida Lothário Meissner, 632, Jardim Botâmico, Curitiba, Paraná, Brasil. Faculdade de Tecnologia de Curitiba – FATEC-PR, Itacolomi, 450, Portão, Curitiba, Paraná, Brasil. E-mail: victor.cremonez@gmail.com; direcaoacademica@fatecpr.edu.br
2 Departamento de Engenharia e Tecnologia Florestal, Universidade Federal do Paraná, Avenida Lothário Meissner, 632, Jardim Botâmico, Curitiba, Paraná, Brasil, E-mail: dile.stremel@gmail.com
3 Departamento de Engenharia e Tecnologia Florestal, Universidade Federal do Paraná, Avenida Lothário Meissner, 632, Jardim Botâmico, Curitiba, Paraná, Brasil, E-mail: mailjmatos.ufpr.br
4 Departamento de Engenharia e Tecnologia Florestal, Universidade Federal do Paraná, Avenida Lothário Meissner, 632, Jardim Botâmico, Curitiba, Paraná, Brasil. E-mail: rjkklitzke@gmail.com
RESUMO: O objetivo deste trabalho foi estimar o coeficiente de transferência de massa e validar um modelo dinâmico não linear para um secador solar de madeira e biomassa. Para tal, foi construída uma estufa solar para secagem de madeira serrada e biomassa, com aproximadamente 1m³ de capacidade. Na estufa, foram secas tábuas de Eucalyptus spp.. Para a modelagem dinâmica foi proposto um balanço dinâmico em torno do material sólido, levando em conta a perda cinética da taxa de secagem em que esta depende do coeficiente de transferência de massa, parâmetro este que será ajustado levando em consideração a dinâmica do ambiente de secagem. Na otimização, foi utilizado o método dos mínimos quadrados não linear. Como resultado, foi possível elaborar um modelo dinâmico para a perda de umidade em relação ao tempo na secagem solar, bem como o coeficiente de transferência de massa. É possível concluir que o coeficiente de transferência de massa e os modelos encontrados podem ser utilizados para estimar os parâmetros de secagem em outras condições ambientais, como outra época do ano, outra cidade ou até outro país, melhorando assim as perspectivas do uso da secagem solar no meio rural.
Palavras-chave: taxa de secagem, secagem de madeira, secagem de biomassa.
ESTIMATION OF MASS TRANSFER COEFFICIENT AND VALIDATION OF A NON-LINEAR DYNAMIC MODEL FOR A SOLAR DRYER
ABSTRACT: The aim of this work was to estimate the mass transfer coefficient and to validate a dynamic non-linear model for a solar wood and biomass dryer. For this purpose, a solar dryer greenhouse was built to dry sawn wood and biomass, with approximately 1m³ of capacity. In the solar dryer, were dried boards of Eucalyptus spp.. For dynamic modeling, a dynamic balance around the solid material was proposed, taking into account the kinetic loss of the drying rate, which depends on the mass transfer coefficient, a parameter that will be adjusted taking into account the dynamics of the drying environment. in optimization, the nonlinear least squares method was used. As a result, it was possible to develop a dynamic model for the loss of moisture in relation to time in solar drying, as well as the mass transfer coefficient. It is possible to conclude that the mass transfer coefficient and the models found can be used to estimate drying parameters in other environmental conditions, such as: another time of the year, another city or even in another country, thus improving the prospects for the use of solar drying in rural areas.
Keywords: drying rate, wood drying, biomass drying.
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Addison, J. A., and M. W. Hart. "Spawning, copulation and inbreeding coefficients in marine invertebrates." Biology Letters 1, no. 4 (August 5, 2005): 450–53. http://dx.doi.org/10.1098/rsbl.2005.0353.
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Patterns of population genetic variation have frequently been understood as consequences of life history covariates such as dispersal ability and breeding systems (e.g. selfing). For example, marine invertebrates show enormous variation in life history traits that are correlated with the extent of gene flow between populations and the magnitude of differentiation among populations at neutral genetic markers ( F ST ). Here we document an unexpected correlation between marine invertebrate life histories and deviation from Hardy–Weinberg equilibrium (non-zero values of F IS , the inbreeding coefficient). F IS values were significantly higher in studies of species with free-spawned planktonic sperm than in studies of species that copulate or have some form of direct sperm transfer to females or benthic egg masses. This result was robust to several different analytical approaches. We note several mechanisms that might contribute to this pattern, and appeal for more studies and ideas that might help to explain our observations.
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Kaseno, Kaseno, and T. Kokugan. "Pengaruh Gelombang Ultrasonik Pada Karakteristik Membran Ultrafiltrasi." REAKTOR 7, no. 1 (June 19, 2017): 1. http://dx.doi.org/10.14710/reaktor.7.1.1-6.
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Untuk mengetahui pengaruh gelombang atau daya ultrasonik (Ultrasonic force, USF) terhadap karakteristik membrane ultrafiltrasi (UF) yang terbuat dari keramik (alumina, Al2O3), maka dilakukan percobaan permeasi pada skala laboratorium untuk 3 jenis larutan yaitu : larutan ovalbumin, larutan dextran, dan larutan polyvinyl alcohol (PVA). USF dipancarkan pada 1/8 bagian dari batang membran keramik pada saat percobaan permeasi dilaksanakan. Hasil percobaan membuktikan bahwa USF menghambat pembentukan lapisan gel pada permukaan membrane dan polarisasi konsentrasi di dekat permukaan membrane. Hal ini disimpulkan dari penurunan rejeksi dan peningkatan fluk membrane UF, serta meningkatnya koefisien transfer massa (mass transfer coefficient) 1,4 kali jika dibandingkan dengan tanpa pengukuran USF.Kata kunci : Gelombang ultrasonic, membrane ultrafiltrasi, dan koefisien transfer masa.
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Dai, Yun Yun. "Cause Analysis and Stability Estimation about Taziping Landslide." Applied Mechanics and Materials 405-408 (September 2013): 2330–33. http://dx.doi.org/10.4028/www.scientific.net/amm.405-408.2330.
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Taziping Landslide is in the border of Ganluo County. Its a medium-sized landslide performed by two slip masses, an upper one and a lower one. Now its in the stage of creep deformation, which potentially threatens people's lives and property. This paper analyses landslide geology, characteristic and creeping formation mechanism of Taziping landslide. And then evaluate its stability by transfer coefficient method. Lastly put forward the comprehensive improvement scheme, retaining project as well as surface drainage.
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Lafrance, P., O. Banton, and P. Gagné. "Exportation saisonnière d'herbicides vers les cours d'eau mesurée sur six champs agricoles sous quelques pratiques culturales du maïs (Basses-Terres du St-Laurent)." Revue des sciences de l'eau 10, no. 4 (April 12, 2005): 439–59. http://dx.doi.org/10.7202/705288ar.
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L'identification de pratiques agricoles qui minimisent les risques de contamination des eaux de surface nécessite d'évaluer l'importance des voies de transfert des herbicides vers les cours d'eau. Le but de cette étude est d'évaluer à l'échelle du champ agricole et pour une saison de culture l'exportation effective de l'atrazine et du métolachlore par ruissellement de surface et par drainage, ceci pour des conditions pédo-climatiques et agronomiques représentatives de la culture intensive du maïs-grain dans les Basses-Terres du St-Laurent (Québec). Pour les deux premiers événements pluviaux d'importance suivant l'application des herbicides, seulement deux des six champs étudiés ont présenté un ruissellement quittant le champ : les concentrations en herbicides ont atteint 1200 mg/L et 2400 mg/L. La charge exportée en herbicides semble inférieure dans le cas du non travail du sol (semis direct), comparativement au labour conventionnel. Les concentrations en herbicides dans l'eau de drainage sont inférieures à 6 mg/L (pour la majorité inférieures à 1-2mg/L) pour quatre champs, alors que deux champs ont présenté des concentrations atteignant 40-60 mg/L. La charge exportée par drainage apparaît être faible dans le cas de l'application d'herbicides en bandes, comparativement à l'application en surface totale. La masse en herbicides exportée par ruissellement (estimée à partir de coefficients de ruissellement probables) serait supérieure à celle par drainage. Une démarche destinée à diminuer les masses en herbicides exportées devrait ainsi viser la principale voie de cette exportation, c'est-à-dire le ruissellement de surface.
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Ariono, Danu, Dwiwahju Sasongko, and Priyono Kusumo. "Dinamika tetes dalam kolom isian." Jurnal Teknik Kimia Indonesia 7, no. 1 (October 9, 2018): 710. http://dx.doi.org/10.5614/jtki.2008.7.1.1.
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To date, evaluation of the performance of liquid-liquid extraction in packed columns has not been able to produce satisfactory results, because the correlations used in this evaluation are empirical in nature, with a very limited range of validity. One of the causes of this limitation is the use of the assumption that the dynamics of liquid dispersed in droplets is constant (in terms of shape, dimensions, and numbers), so that the mass transfer interfacial area and mass transfer coefficient in the column are assumed to be constant. In reality, dynamics of droplets in a column is not constant, due to the imbalance between droplet coalescence and disintegration. For a given droplet diameter, there is an increase in numbers of droplets due to coalescence of smaller droplets, and a decrease in numbers of droplets due to disintegration into smaller droplets. These coalescence and disintegration phenomena may be caused by various factors, including the existence of packings which impede the flow of droplets. These phenomena impact the mass transfer rate from continuous to dispersed phase, and vice versa, due to a variation in the interfacial contact area and mass transfer coefficient. The observation of droplet dynamics from droplet formation until its motion through void spaces between packings is a critical factor in developing a model that can describe the performance of the packed column. The dynamics of droplets is influenced by various operational and physical variables. A droplet dynamics experiment has been undertaken, aimed at obtaining the droplet size distribution at specific heights along the column. This distribution is to be used to develop mass transfer coefficient correlations in the continuous and dispersed phases.Keywords: droplet size distribution, packed column Abstrak Evaluasi unjuk kerja ekstraksi cair-cair dalam kolom isian (packed column) hingga saat ini belum dapat memberikan hasil yang memuaskan karena korelasi-korelasi yang digunakan masih bersifat empiris serta daerah keberlakuannya sangat terbatas. Salah satu penyebab keterbatasan berlakunya korelasi tersebut ialah penggunaan anggapan bahwa dinamika cairan yang terdispersi dalam bentuk tetesan bersifat konstan (bentuk, ukuran serta jumlahnya), sehingga harga luas perpindahan massa dan harga koefisien perpindahan massa dalam kolom dianggap tetap. Kenyataannya dinamika tetesan dalam kolom tidak konstan akibat adanya tetesan yang bergabung dan pecah dalam jumlah yang tidak sama. Pada suatu harga diameter tetesan tertentu, ada penambahan jumlah tetesan akibat penggabungan tetesan tetesan yang ukurannya lebih kecil serta adanya pengurangan jumlah tetesan akibat pecahnya tetesan menjadi tetesan-tetesan yang lebih kecil. Peristiwa penggabungan dan pemecahan tetesan dapat disebabkan berbagai faktor temasuk adanya isian yang menghalangi gerakan tetesan. Kejadian tersebut akan mempengaruhi laju proses perpindahan massa dari fasa kontinyu ke fasa terdispersi atau sebaliknya, karena adanya variasi luas permukaan kontak serta koefisien perpindahan massanya. Pengamatan dinamika tetesan mulai saat pembentukan tetes hingga pergerakannya saat melewati sela-sela isian merupakan faktor penting dalam membangun model yang dapat menggambarkan unjuk kerja kolom isian. Dinamika tetesan tersebut dipengaruhi oleh berbagai variabel operasi dan variabel fisik. Eksperimen dinamika fetes yang dilakukan diarahkan untuk memperoleh distribusi ukuran tetes pada posisi ketinggian tertentu dan distribusi tersebut akan digunakan untuk pengembangan korelasi koefisien perpindahan massa difasa dispersi danfasa kontinyu.Kata kunci: distribusi ukuran tetes, kolom isian.
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Zhang, Shuguang, Pingping Lu, and Hongwei Wang. "Numerical Simulation Analysis of Unsteady Temperature in Thermal Insulation Supporting Roadway." Mathematical Problems in Engineering 2019 (June 10, 2019): 1–8. http://dx.doi.org/10.1155/2019/6279164.
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High geothermal hazard is a basic problem that must be solved in deep mining; thereby the research on thermal insulation supporting for high temperature control of deep roadway is increasing. However, the quantitative analysis of its thermal insulation effect is yet to be carried out. By building the physical model and control equations of the thermal insulation supporting roadway and considering heat-humidity transfer at wall, the temperature field distribution of surrounding rock and airflow is numerically calculated. Based on numerical simulation results, the evolution law of temperature with ventilation time is analyzed at airflow inlet, outlet, and different sections, then the variation law of surface heat transfer coefficient with position and time is obtained. For heat insulation support structure, the results show that it is not obvious to change the distribution law of temperature field, but it is effective to weaken the convection heat transfer between surrounding rock and airflow. In the main airflow area, the rate of heat exchange gradually decreases with the heat exchange becoming more and more sufficient; in boundary layer, the airflow temperature quickly transits from the wall temperature to that of the main airflow area because of intense collisions of airflow masses, so the mechanism of temperature change is different. The surface heat transfer coefficient well reflected the unstable heat-humidity transfer, especially in the beginning of ventilation or at airflow inlet. Therefore, the heat insulation supporting structure is helpful to the auxiliary cooling of high temperature mine.
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Fakhry, Muhammad Naufal, and Suprihastuti Sri Rahayu. "Pengaruh Suhu pada Esterifikasi Amil Alkohol dengan Asam Asetat Menggunakan Asam Sulfat sebagai Katalisator." Jurnal Rekayasa Proses 10, no. 2 (November 20, 2016): 64. http://dx.doi.org/10.22146/jrekpros.33339.
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Ester compounds are widely used as solvents, artificial aroma materials, and precursors of pharmaceutical ingredients. One of the ester compounds widely used in the chemical industry is amyl acetate. Amyl acetate can be synthesized by esterification of amyl alcohol and acetic acid, which is a liquid-liquid heterogeneous reaction. This study aims to study the kinetics of this particular reaction focusing on the effect of temperature. The catalyst used in this study was sulfuric acid. The mole ratio of acetic acid to amyl alcohol used was 2: 5. Reaction was run at constant temperature in a three-neck flask as a batch reactor. The acetic acid and sulfuric acid were first put into the reactor and heated while stirring. After reaching a certain temperature, the preheated amyl alcohol was added into the reactor. During reaction, the temperature was maintained at the desired temperature. The reactants and products involved in this reaction were immiscible. The product phases were separated and then the remaining acetic acid content in the water-soluble phase was analyzed by volumetric method. The study was carried out in 4 variations of temperature i.e. 70, 80, 90, and 100C. The results of experimental data analysis showed that the reaction will be faster when the temperature is higher. The mass transfer from the acetic acid phase to the amyl alcohol phase increased with the increase of temperature. The value of the reaction rate constant, the overall mass transfer coefficient, and the Henry’s constant were evaluated by the parameter fitting method using the MATLAB program. Based on the evaluation at the highest reaction temperature 100oC, the rate constant was 0,0134 mL.mole-2s-1, the mass transfer coefficient was 0,3180 L s-1, and the Henry’s constant was 0,0174 (mole/L)A in phase II/(mole/L)A in phase I. Keywords: esterification, immiscible, amyl acetate, mass transfer Senyawa ester banyak dipakai sebagai solven, bahan aroma buatan, dan prekursor bahan-bahan farmasi. Salah satu senyawa ester yang banyak digunakan dalam industri kimia dalah amil asetat. Ester amil asetat dapat disintesis melalui reaksi esterifikasi dengan bahan baku amil alkohol dan asam asetat. Reaksi ini merupakan reaksi heterogen cair-cair. Penelitian ini bertujuan untuk mempelajari kinetika reaksi tersebut, terutama pengaruh variabel suhu. Untuk mempercepat laju reaksi ditambahkan asam sulfat. Perbandingan mol pereaksi asam asetat:amil alkohol yang digunakan sebesar 2:5. Reaksi dijalankan dalam reaktor batch dan suhu dijaga konstan. Reaktan dan katalisator dicampur dalam labu leher tiga. Asam asetat dan asam sulfat dituangkan ke dalam reaktor, dipanaskan dan diaduk sampai suhu tertentu. Selanjutnya amil alkohol yang telah dipanaskan sebelumnya hingga suhu tertentu dituangkan. Selama reaksi suhu dipertahankan konstan. Reaktan dan produk yang terlibat dalam reaksi ini berupa campuran immiscible. Produk yang terdiri dari dua fase dipisahkan antar fasenya kemudian fase yang larut dalam air dianalisis kadar asam asetat sisanya dengan metode volumetri. Reaksi dilakukan masing-masing pada suhu 70, 80, 90, dan 100oC. Hasil analisis menunjukkan bahwa reaksi akan semakin cepat apabila suhu semakin tinggi. Transfer massa dari fase asam asetat ke fase amil alkohol semakin besar pula dengan adanya kenaikan suhu. Nilai konstanta kecepatan reaksi, koefisien transfer massa overall, dan konstanta Henry dievaluasi dengan metode fitting parameter menggunakan program MATLAB. Berdasarkan evaluasi pada suhu reaksi tertinggi yaitu 100oC diperoleh nilai konstanta kecepatan reaksi sebesar 0,0134 mL.mol-2s-1, koefisien transfer massa overall sebesar 0,318 mL s-1, dan konstanta Henry sebesar 0,0174 (mol/L)A di fase II/(mol/L)A di fase I. Kata kunci: esterifikasi, immiscible, amil asetat, transfer massa
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Mulyono, Panut. "KOEFISIEN PERPINDAHAN MASSA VOLUMETRIS KESELURUHAN PADA EKSTRAKSI Cu DARI LARUTAN CuSO4.5H2O DENGAN TRIRUTYL PHOSPHATE-KEROSIN DALAM DOUBLE-STAGE MIXER-SETTLER." Jurnal Teknik Kimia Indonesia 7, no. 1 (October 9, 2018): 731. http://dx.doi.org/10.5614/jtki.2008.7.1.4.
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Copper has been extracted by trtbuthyl phosphate-kerosene from a dilute aqueous solution with a double- stage mixer-settler extraction column. The extraction column used in this experiment was made of glass. The mixer diameter was equal to the diameter of settler was 13 cm. Both the mixer and settler heights were 8 cm. Drop coalescer was mounted in the middle of mixer and settler separator. The diameter of drop coalescer was 6 cm with the thickness of 1 cm. The hole diameter of drop coalescer was 1 mm The stirrer used in this experiment was cross flat blade with the diameter and width of the impeller was 6 cm and 8 mm, respectively. The overall volumetric coefficient of mass transfer (Kca) increased by increasing the flowrate of the continuous phase (Lc) at the constants stirring speed (N) and flowrate of the dispersed phase (Ld). The increase of Lc from 4.1634 cm3/second to 17.9436 cm3/second increased the Kca value from 6.6387x10-5/second to 23.1561x10-5/second or 248.8% The value of Kca was also increase by increasing N at the constant values of Lc and Ld Thie increase of N from 3.3333 rps to 8.3333 rps increased the Kca value from 6.0288x10-5/second to 6.6387x10-5/second or 10.1%.Keywords: Mass Transfer Coefficient, Extraction, Copper, Double-Stage Mixer-SettlerAbstrak Penelitian ini mempelajari perpindahan massa antar fasa pada ekstraksi Cu dart larutan CuSO4.5H2O dengan menggunakan pelarut tributyl phosphate dalam kerosin yang dilakukan dalam kolom ekstraksi double-stage mixer-settler yang dtsusun vertikal. Kolom ekstraksi mixer-settler dibuat darti gelas dengan diameter mixer sama dengan diameter sealer, yaitu 13 cm. Tinggi mixer juga sama dengan tinggt settler, yaitu 8 cm. Diameter drop coalescer 8 cm, tebal 1 cm, dan diameter lubangnya 1 mm. Pengaduk yang digunakan berbentuk flat blade dengan diameter 6 cm dan lebar blade 8 mm. Koeftsien perpindahan massa volumetris keseluruhan (Kca) naik dengan naiknya kecepatan alir fasa kontinyu (Lc) pada kecepatan putaran pengaduk (N) dan kecepatan alir fasa dispersi (Ld) tetap. Kenatkan nilai Lc dart 4,1634 cm3/detik menjadi 17,9436 cm3/detik meningkatkan nilai Kca dart 6,6387x10-5/detik menjadi 23,1561x10-5/detik atau 248,8% Kca juga naik dengan naiknya N pada Lc dan Ld yang tetap. Kenaikan nilai N dart 3,3333 rps menjadi 8,3333 rps meningkatkan nilai Kca dart 6,0288x10-5/detik menjadt 6,6387x10-5/detik atau 10,1%.Kata Kunci : Koefesien Perpindahan Massa, Ekstraksi, Tembaga, Double-Stage Mixer-Settler
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Dunn, M. A., M. H. Green, and R. M. Leach. "Kinetics of copper metabolism in rats: a compartmental model." American Journal of Physiology-Endocrinology and Metabolism 261, no. 1 (July 1, 1991): E115—E125. http://dx.doi.org/10.1152/ajpendo.1991.261.1.e115.
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odel-based compartmental analysis was used to describe data on the whole body kinetics of copper metabolism in rats. Data were collected on recovery of radio-copper in plasma, liver, skin, skeletal muscle, bile, and feces for 3 days after the injection of 10 micrograms iv of copper labeled with 64Cu. Data on copper masses and on 64Cu kinetics were analyzed by the stimulation, analysis, and modeling computer programs. Observed data were fit to a 16-component “working hypothesis” model; fractional transfer coefficients were estimated, and steady-state compartment masses and copper transfer rates were calculated. The model postulates a rapid turnover of plasma nonceruloplasmin (NCp) copper (8.5 h-1), which exchanged a large amount of copper with extrahepatic tissues (16 micrograms/h) as well as liver (13 micrograms/h). In comparison, ceruloplasmin (Cp) transferred relatively little copper to tissues (less than 1 microgram/h). NCp copper is postulated to be the precursor for biliary copper. Regarding the intracellular metabolism of copper in hepatic and extrahepatic tissues, the data were compatible with a faster turning-over compartment that exchanged copper with NCp and a slower turning-over compartment with input from Cp. In the liver, the slower turning-over compartment was the copper present in peak II (mol mass 30,000–40,000 Da); this received much of its input from the faster turning-over compartment (peak III), which was hypothesized to represent, in large part, copper in metallothionein.
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Rodgers, Bryan, Suresh Goyal, Gerard Kelly, and Michael Sheehy. "The Dynamics of Multiple Pair-Wise Collisions in a Chain for Designing Optimal Shock Amplifiers." Shock and Vibration 16, no. 1 (2009): 99–116. http://dx.doi.org/10.1155/2009/989146.
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The major focus of this work is to examine the dynamics of velocity amplification through pair-wise collisions between multiple masses in a chain, in order to develop useful machines. For instance low-cost machines based on this principle could be used for detailed, very-high acceleration shock-testing of MEMS devices. A theoretical basis for determining the number and mass of intermediate stages in such a velocity amplifier, based on simple rigid body mechanics, is proposed. The influence of mass ratios and the coefficient of restitution on the optimisation of the system is identified and investigated. In particular, two cases are examined: in the first, the velocity of the final mass in the chain (that would have the object under test mounted on it) is maximised by defining the ratio of adjacent masses according to a power law relationship; in the second, the energy transfer efficiency of the system is maximised by choosing the mass ratios such that all masses except the final mass come to rest following impact. Comparisons are drawn between both cases and the results are used in proposing design guidelines for optimal shock amplifiers. It is shown that for most practical systems, a shock amplifier with mass ratios based on a power law relationship is optimal and can easily yield velocity amplifications of a factor 5–8 times. A prototype shock testing machine that was made using above principles is briefly introduced.
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MASON, G. R., A. M. PETERS, E. BAGDADES, M. J. MYERS, D. SNOOK, and J. M. B. HUGHES. "Evaluation of pulmonary alveolar epithelial integrity by the detection of restriction to diffusion of hydrophilic solutes of different molecular sizes." Clinical Science 100, no. 3 (January 25, 2001): 231–36. http://dx.doi.org/10.1042/cs1000231.
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The rate of transfer of a hydrophilic solute from the alveoli to pulmonary blood following inhalation as an aerosol depends on the molecular size of the solute and the permeability of the alveolar epithelium. The value of this measurement for assessing damage to the epithelium in lung disease is compromised by cigarette smoking, which accelerates clearance by unknown mechanisms. The rates of clearance of 99mTc-labelled diethylenetriaminepenta-acetic acid (DTPA) (molecular mass 492 Da) and 113mIn-labelled biotinylated DTPA (B-DTPA) (molecular mass 1215 Da) were monitored simultaneously by dynamic γ-radiation camera imaging following simultaneous inhalation, and compared between eight normal non-smoking subjects and nine habitual cigarette smokers. The clearance rates of DTPA were 0.95 (S.D. 0.39)%/min in non-smokers and 4.13 (1.06) %/min in smokers. These were about twice the clearance rates of B-DTPA, which in the corresponding groups were 0.41 (0.26) and 2.12 (0.72)%/min respectively. The ratio of the B-DTPA/DTPA clearance rates was, in all subjects, less than the ratio (0.74) of the cube roots of the molecular masses of the solutes, assumed to correspond to the ratio of their free diffusion coefficients in water, and was not significantly different between smokers and non-smokers. As alveolar permeability increased, the ratio of clearance rates in the entire population showed a significant trend to increase in a non-linear fashion towards the value corresponding to the ratio of the free diffusion coefficients. We conclude that the diffusion of at least the larger of these two solutes through the pulmonary alveolar epithelium is restricted (i.e. associated with a reflection coefficient greater than zero). Cigarette smoking, however, does not appear to cause a loss of this restriction, and may increase solute clearance by other mechanisms, such as reducing fluid volume within the alveolus, thereby raising the local radiotracer concentration, or increasing the number of pores available for solute exchange without affecting pore size. Conversely, if restriction was lost in lung disease, the ratio of the clearance rates of two solutes of dissimilar sizes could be used to detect disease in smokers as well as non-smokers.
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Renault, Lionel, James C. McWilliams, and Pierrick Penven. "Modulation of the Agulhas Current Retroflection and Leakage by Oceanic Current Interaction with the Atmosphere in Coupled Simulations." Journal of Physical Oceanography 47, no. 8 (August 2017): 2077–100. http://dx.doi.org/10.1175/jpo-d-16-0168.1.
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AbstractCoupled ocean–atmosphere simulations are carried out for the Mozambique Channel, the Agulhas Current system, and the Benguela upwelling system to assess the ocean surface current feedback to the atmosphere and its impact on the Agulhas Current (AC) retroflection and leakage. Consistent with previous studies, the authors show that the current feedback slows down the oceanic mean circulation and acts as an oceanic eddy killer by modulating the energy transfer between the atmosphere and the ocean, reducing by 25% the mesoscale energy and inducing a pathway of energy transfer from the ocean to the atmosphere. The current feedback, by dampening the eddy kinetic energy (EKE), shifts westward the distribution of the AC retroflection location, reducing the presence of eastern retroflections in the simulations and improving the realism of the AC simulation. By modulating the EKE, the AC retroflection and the Good Hope jet intensity, the current feedback allows a larger AC leakage (by 21%), altering the water masses of the Benguela system. Additionally, the eddy shedding is shifted northward and the Agulhas rings propagate less far north in the Atlantic. The current–wind coupling coefficient sw is not spatially constant: a deeper marine boundary layer induces a weaker sw. Finally the results indicate that the submesoscale currents may also be weakened by the current feedback.
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Mulyono, Panut, I. Made Bendiyasa, S. Sarto, Tri Mustika, and H. Heriyanto. "Koefisien perpindahan massa volumetris keseluruhan pada ekstraksi Cu dari larutan CuSO4.5H2O dengan tributyl phosphate-kerosin dalam double-stage mixer-settler." Jurnal Teknik Kimia Indonesia 5, no. 1 (October 2, 2018): 357. http://dx.doi.org/10.5614/jtki.2006.5.1.4.
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Copper is one of the hazardous materials and is found in some industrial waste waters. Extraction is thought to be an effective removal technique for copper from dilute solution. In this study, copper has been extracted by tributhyl phosphate-kerosene from a dilute aqueous solution with a double-stage mixer-settler extraction column. The extraction column used in this experiment was made of glass. The mixer diameter was equal to the diameter of settler was 13 cm. Both the mixer and settler heights were 8 cm. Drop coalescer was mounted in the middle of mixer and settler separator. The diameter of drop coalescer was 6 cm with the thickness of 1 cm. The hole diameter of drop coalescer was 1 mm. The stirrer used in this experiment was cross flat blade with the diameter and width of the impeller was 6 cm and 8 mm, respectively. The overall volumetric coefficient of mass transfer (Kca) increased by increasing the flow rate of the continuous phase (Lo) at the constants stirring speed (N) and flow rate of the dispersed phase (Ld). The increase of Lc from 4.1634 cm3/second to 17.9436 cm3 /second increased the Kca value from 6.6387x10-5/second to 23.1561x 10-5 /second or 248.8%. The value of Kca was also increase by increasing N at the constant values of Lc and Ld The increase of N from 3.3333 rps to8.3333 rps increased the Kca value from 6.0288x10-5 second to 6.6387x10-5 second or 10.1%.Keywords: Mass Transfer Coefficient, Extraction, Copper, Double-stage Mixer-settler AbstrakTembaga (Cu) merupakan logam berat yang bila terbuang ke lingkungan merupakan zat pencemar yang berbahaya. Ekstraksi dapat digunakan dengan efektif untuk memungut Cu dari limbah cair walaupun dalam konsentrasi yang rendah. Penelitian ini mempelajari perpindahan massa antarfasa pada ekstraksi Cu dari larutan CuSO4.5H2O dengan menggunakan pelarut tributyl phosphate dalam kerasin yang dilakukan dalam kolom ekstraksi double-stage mixer-settler yang disusun vertikal. Kolom ekstraksi mixer-settler dibuat dari gelas dengan diameter mixer dan diameter settler 13 cm. Tinggi mixer 8 cm. Diameter drop coalescer 8 cm, tebal 1 cm, dan diameter lubangnya 1 mm. Pengaduk yang digunakan berbentuk flat blade dengan diameter 6 cm dan lebar blade 8 mm. Koefisien perpindahan massa volumetris keseluruhan (Kca) naik dengan naiknya kecepatan alir fasa kontinyu (Lc) pada kecepatan putaran pengaduk (N) dan kecepatan alir fasa dispersi (Ld) tetap. Kenaikan nilai Lc dari 4,1634 cm3/detik menjadi 17,9436 cm3/detik meningkatkan nilai Kca dari 6,6387x10-5/detik menjadi 23,1561x10-5/detik atau 248,8%. Kca juga naik dengan naiknya N pada Lc dan Ld yang tetap. Kenaikan nilai N dari 3,3333 rps menjadi 8,3333 rps meningkatkan nilai K.adari 6,0288x10-5 detik menjadi 6,6387x10-5 detik atau 10,1%.Kata Kunci: Koefisien Perpindahan Massa, Ekstraksi, Tembaga, Double-stage Mixer-settler
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Koybakov, S. M., M. Maliktaiuly, S. K. Joldassov, G. A. Sarbasova,, and Zh Yeskermessov. "NEW METHODS TO PROTECT YEAR-AROUND OPERATION CANALS FROM SNOW." NEWS of National Academy of Sciences of the Republic of Kazakhstan 6, no. 444 (December 15, 2020): 102–9. http://dx.doi.org/10.32014/2020.2518-170x.136.
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On the canals of year-around operation, severe snowdrifts concentrated on the surface of the ice cover simultaneously affect both thermal and static loads. When ice melts intensively from the lower surface in areas of accumulation of snow masses, and also due to an increase in the static load from snow, longitudinal cracks form on the ice. The snow saturated with water rising up along the cracks, and a gradual sinking of the snow-ice mass occurs. All this leads to decrease in canal capacity, and in some cases to complete blockage of the flow section by snow-ice mass. The purpose of the paper is to find new ways to protect the canal drift and create an impervious canal profile in areas heavily covered in snow. Snow deposition in the canal bed occurs gradually, starting from the edge of canal closest to the snow collection basin side, followed by an increase in the snowdrift shaft in the direction of the wind as snow blizzard arrives to the canal. We propose the method of protecting the canals from snowdrifts by changing the transverse profile of the canal in the sections highly covered by snow. The transverse canal profile is changed by adding a berm to it with a slope coefficient equal to the coefficient the leeward slope and a height equal to the depth of the canal from the leeward slope depending on exact establishing the limit position of the surface of the snowdrifts, at which the canal is blown without snow deposition, regardless of the amount of snow transfer. The proposed methods can be applied in areas of snow transfer on watering and irrigation canals designed for year-around operation.
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Kartohardjono, Sutrasno, Milasari Herdiana Putri, and Setijo Bismo. "Combination of ozonation and absorption through membrane contactor to remove ammonia from waste water." Jurnal Teknik Kimia Indonesia 11, no. 2 (October 2, 2018): 81. http://dx.doi.org/10.5614/jtki.2012.11.2.3.
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Ammonia in waste water is a major pollutant produced in industrial and agricultural waste water. Ammonia is often removed by conventional technologies such as pack tower aeration, biological treatment or adsorption as ammonium ion onto zeolites. In many cases, conventional methods are very costly and inefficient, and therefore, there is a need for an alternative separation technique for more efficient removal of ammonia from waste waters. The aim of this study is to investigate the performance of the combination of ozonation and absorption through membrane processes to remove ammonia from wastewater using natural hot spring water (NHSW) as absorbent. Experimental results show that operating variables such as time and pH of absorbent solution are found to remarkably influence the removal process efficiency. Based on experimental results ozonation can improve ammonia removal efficiency through the hollow fiber membrane contactor. Ammonia removal efficiencies and overall mass transfer coefficients increase with decreasing pH of absorbent solution. Keywords: ammonia, mass transfer, membrane, ozonation, removal efficiencyAbstrak Amonia di dalam air limbah merupakan polutan utama yang berasal dari air limbah industri dan pertanian. Amonia kebanyak disisihkan dengan teknologi konvensional seperti aerasi di menara isian, pengolahan secara biologi atau penyerapan sebagai ion amonium pada zeolit. Dalam banyak hal, metode konvensional sangat mahal dan kurang efisien, sehingga diperlukan teknik separasi alternatif untuk proses penyisihan amonia dari air limbah yang lebih efisien. Tujuan dari studi ini adalah untuk menyelidiki kinerja kombinasi proses ozonasi dan proses absorbsi melalui membran untuk menyisihkan amonia dari air limbah menggunakan absorben berbahan dasar air dari sumber air panas. Hasil eksperimen memperlihatkan bahwa variabel operasi, seperti waktu dan pH larutan penyerap, sangat mempengaruhi efisiensi proses penyisihan amonia. Berdasarkan hasil eksperimen, ozonasi dapat meningkatkan efisiensi penyisihan ammonia melalui kontaktor membran serat berlubang. Efisiensi penyisihan amonia dan koefisien perpindahan massa keseluruhan naik dengan turunnya pH larutan penyerap.Kata kunci: amonia, perpindahan massa, membran, ozonasi, efisiensi penyisihan
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Hutasuhut, Muhammad Idris. "ANALISIS PERPINDAHAN KALOR KONDENSOR PADA PROSES DISTILASI BIOETANOL SEBAGAI BIOFUEL DARI CAMPURAN LIMBAH BUAH SALAK DENGAN LIMBAH AIR KELAPA." JOURNAL OF MECHANICAL ENGINEERING, MANUFACTURES, MATERIALS AND ENERGY 2, no. 2 (December 28, 2018): 43. http://dx.doi.org/10.31289/jmemme.v2i2.2006.
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<p class="JudulAbstrakEnglish"> </p><p class="JudulAbstrakEnglish">Cadangan bahan bakar fosil Indonesia akan segera habis. Indonesia harus segera melakukan inovasi dan temuan bahan bakar alternative untuk menggatikan bahan bakar fosil tersebut untuk menghindari krisis dan isu lingkungan. Biomassa sebagai salah satu sumber bahan bakar alternative yang tersedia dalam jumlah banyak di Indonesia. Melalui beberapa tahapan proses biomassa dapat dirubah menjadi bahan bakar bioethanol. Salah satu proses yang dimaksud dengan cara termokimia yaitu distilasi. Distilasi merupakan proses pemisahan fasa berdasarkan titik didih fasa itu sendiri. Uap mengalir dalam pipa masuk ke dalam kondensor dengan ukuran Ø 8.89x10<sup>-2</sup> m dan panjang L 3.4 x10<sup>-2</sup>. Didalam kondesnor terjadi perpindahan panas secara konveksi. Perbedaan temperature pada proses kondensasi antara fluida uap yang mengalir dalam pipa dengan fluida air pendingin yang mendinginkan dinding kondesor direkam menggunakan perankat akuisisi. Oleh karena itu, penelitian ini bertujuan untuk menganalisis perpindahan panas konveksi pada kondensor dan mengitung hasil luaran bioethanol secara teoritis berdasarkan massa kondensat uap fermentor. Dari hasil analisis diperoleh perpindahan panas konveksi sebesar 0.2752 kW. Laju massa uap fermentor 1.192 x 10<sup>-4</sup> kg/s, koefisien perpindahan kalor kondensasi 340.7161 W/m<sup>2 O</sup>C, laju massa kondensat 1.01x 10<sup>-5</sup> kg/s. Laju massa kondensat yang diperoleh 8% merupakan hasil luaran biofuel atau bioethanol.</p><p><strong><em><br /></em></strong></p><p class="JudulAbstrakEnglish"><strong>Abstract</strong></p><p class="Howtocite">Indonesia's fossil fuel reserves will soon run out. Indonesia must immediately innovate and search alternative fuels to replace fossil fuels to avoid crises and environmental issues. Biomass as one of the alternative sources of fuel available in large quantities in Indonesia. Through several stages, the process of biomass can be converted into bioethanol fuel. One of the processes referred to by thermochemical methods is distillation. Distillation is a phase separation process based on the boiling point itself. Steam flows in the pipe into the condenser with a size of Ø 8.89x10-2 m and length L 3.4 x10-2. In the condenser, there is convection heat transfer. The temperature difference in the condensation process between the vapor fluid flowing in the pipe and the cooling water fluid that cools the condenser wall is recorded using the acquisition role. Therefore, this study aims to analyze the convection heat transfer in the condenser and to calculate the bioethanol output theoretically based on the mass of the fermentor vapor condensate. From the analysis results obtained convection heat transfer of 0.2752 kW. The fermentor vapor mass rate is 1,192 x 10-4 kg / s, the condensation heat transfer coefficient is 340.7161 W / m2 OC, the condensate mass rate is 1.01x 10-5 kg / s. The condensate mass rate obtained by 8% is the result of biofuel or bioethanol output.</p><p class="Howtocite"> </p><p><strong><em><br /></em></strong></p>
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Holko, Ladislav, Michal Danko, and Patrik Sleziak. "Analysis of changes in hydrological cycle of a pristine mountain catchment. 2. Isotopic data, trend and attribution analyses." Journal of Hydrology and Hydromechanics 68, no. 2 (June 1, 2020): 192–99. http://dx.doi.org/10.2478/johh-2020-0011.
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Abstractδ18O in precipitation at station Liptovský Mikuláš (about 8.5 km south from the outlet of the Jalovecký Creek catchment) remains constantly higher since 2014 that might be related to greater evaporation in the region of origin of the air masses bringing precipitation to the studied part of central Europe. Increased δ18O values are reflected also in the Jalovecký Creek catchment runoff. Seasonality of δ18O in the Jalovecký Creek became less pronounced since 2014. The most significant trends found in annual hydrological data series from the catchment in the study period 1989–2018 have the correlation coefficients 0.4 to 0.7. These trends are found in the number of flow reversals (change from increasing to decreasing discharge and vice versa), June low flow, number of simple runoff events in summer months (June to September) and the flashiness index. The attribution analysis suggests that drivers responsible for the changes in these data series include the number of periods with precipitation six and more days long, total precipitation amount in February to June, number of days with precipitation in June to September and total precipitation in May on days with daily totals 10 mm and more, respectively. The coefficients of determination show that linear regressions between the drivers and supposedly changed data series explain only about 31% to 36% of the variability. Most of the change points detected in the time series by the Wild Binary Segmentation method occur in the second and third decades of the study period. Both hydrometric and isotopic data indicate that hydrological cycle in the catchment after 2014 became different than before.
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El-Sayed, Tamer Ahmed, and Said Hamed Farghaly. "A Normalized Transfer Matrix Method for the Free Vibration of Stepped Beams: Comparison with Experimental and FE(3D) Methods." Shock and Vibration 2017 (2017): 1–23. http://dx.doi.org/10.1155/2017/8186976.
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The exact solution for multistepped Timoshenko beam is derived using a set of fundamental solutions. This set of solutions is derived to normalize the solution at the origin of the coordinates. The start, end, and intermediate boundary conditions involve concentrated masses and linear and rotational elastic supports. The beam start, end, and intermediate equations are assembled using the present normalized transfer matrix (NTM). The advantage of this method is that it is quicker than the standard method because the size of the complete system coefficient matrix is 4 × 4. In addition, during the assembly of this matrix, there are no inverse matrix steps required. The validity of this method is tested by comparing the results of the current method with the literature. Then the validity of the exact stepped analysis is checked using experimental and FE(3D) methods. The experimental results for stepped beams with single step and two steps, for sixteen different test samples, are in excellent agreement with those of the three-dimensional finite element FE(3D). The comparison between the NTM method and the finite element method results shows that the modal percentage deviation is increased when a beam step location coincides with a peak point in the mode shape. Meanwhile, the deviation decreases when a beam step location coincides with a straight portion in the mode shape.
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Koss, Abigail R., Kanako Sekimoto, Jessica B. Gilman, Vanessa Selimovic, Matthew M. Coggon, Kyle J. Zarzana, Bin Yuan, et al. "Non-methane organic gas emissions from biomass burning: identification, quantification, and emission factors from PTR-ToF during the FIREX 2016 laboratory experiment." Atmospheric Chemistry and Physics 18, no. 5 (March 7, 2018): 3299–319. http://dx.doi.org/10.5194/acp-18-3299-2018.
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Abstract. Volatile and intermediate-volatility non-methane organic gases (NMOGs) released from biomass burning were measured during laboratory-simulated wildfires by proton-transfer-reaction time-of-flight mass spectrometry (PTR-ToF). We identified NMOG contributors to more than 150 PTR ion masses using gas chromatography (GC) pre-separation with electron ionization, H3O+ chemical ionization, and NO+ chemical ionization, an extensive literature review, and time series correlation, providing higher certainty for ion identifications than has been previously available. Our interpretation of the PTR-ToF mass spectrum accounts for nearly 90 % of NMOG mass detected by PTR-ToF across all fuel types. The relative contributions of different NMOGs to individual exact ion masses are mostly similar across many fires and fuel types. The PTR-ToF measurements are compared to corresponding measurements from open-path Fourier transform infrared spectroscopy (OP-FTIR), broadband cavity-enhanced spectroscopy (ACES), and iodide ion chemical ionization mass spectrometry (I− CIMS) where possible. The majority of comparisons have slopes near 1 and values of the linear correlation coefficient, R2, of > 0.8, including compounds that are not frequently reported by PTR-MS such as ammonia, hydrogen cyanide (HCN), nitrous acid (HONO), and propene. The exceptions include methylglyoxal and compounds that are known to be difficult to measure with one or more of the deployed instruments. The fire-integrated emission ratios to CO and emission factors of NMOGs from 18 fuel types are provided. Finally, we provide an overview of the chemical characteristics of detected species. Non-aromatic oxygenated compounds are the most abundant. Furans and aromatics, while less abundant, comprise a large portion of the OH reactivity. The OH reactivity, its major contributors, and the volatility distribution of emissions can change considerably over the course of a fire.
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Woo, Seunghoon, and Donghoon Shin. "A Double Sky-Hook Algorithm for Improving Road-Holding Property in Semi-Active Suspension Systems for Application to In-Wheel Motor." Applied Sciences 11, no. 19 (September 24, 2021): 8912. http://dx.doi.org/10.3390/app11198912.
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This paper presents a double sky-hook algorithm for controlling semi-active suspension systems in order to improve road-holding property for application in an in-wheel motor. The main disadvantage of the in-wheel motor is the increase in unsprung masses, which increases after shaking of the wheel, so it has poor road-holding that the conventional theoretical sky-hook algorithm cannot achieve. The double sky-hook algorithm uses a combination of damper coefficients, one from the chassis motion and the other from the wheel motion. Computer simulations using a quarter and full car dynamic models with the road conditions specified by ISO2631 showed the effectiveness of the algorithm. It was observed that the algorithm was the most effective in the vicinity of the wheel hop frequency. This paper also proposed the parameter set of the double sky-hook algorithm to differentiate the driving mode of vehicles under advanced development.
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Seo, Sangwon, František Mikšík, Yuta Maeshiro, Kyaw Thu, and Takahiko Miyazaki. "Performance Evaluation of an Adsorption Heat Pump System Using MSC-30/R1234yf Pair with the Impact of Thermal Masses." Applied Sciences 11, no. 5 (March 4, 2021): 2279. http://dx.doi.org/10.3390/app11052279.
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In this study, we evaluated the performance of low Global Warming Potential (GWP) refrigerant R1234yf on the activated carbon (MSC-30) for adsorption heating applications. The adsorption isotherms of MSC-30/R1234yf were measured using a constant-volume–variable-pressure (CVVP) method from very low relative pressure to the practical operating ranges. The data were fitted with several isotherm models using non-linear curve fitting. An improved equilibrium model was employed to investigate the influence of dead thermal masses, i.e., the heat exchanger assembly and the non-adsorbing part of the adsorbent. The model employed the model for the isosteric heat of adsorption where the adsorbed phase volume was accounted for. The performance of the heat pump was compared with MSC-30/R134a pair using the data from the literature. The analysis covered the desorption temperature ranging from 60 °C to 90 °C, with the evaporation temperature at 5 °C and the adsorption temperature and condensation temperature set to 30 °C. It was observed that the adsorption isotherms of R1234yf on MSC-30 were relatively lower than those of R134a by approximately 12%. The coefficient of performance (COP) of the selected pair was found to vary from 0.03 to 0.35 depending on the heat source temperature. We demonstrated that due to lower latent heat, MSC-30/R1234yf pair exhibits slightly lower cycle performance compared to the MSC-30/R134a pair. However, the widespread adaptation of environmentally friendly R1234yf in automobile heat pump systems may call for the implementation of adsorption systems such as the direct hybridization using a single refrigerant. The isotherm and performance data presented in this work will be essential for such applications.
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Coe, H., J. D. Allan, M. R. Alfarra, K. N. Bower, M. J. Flynn, G. B. McFiggans, D. O. Topping, et al. "Chemical and physical characteristics of aerosol particles at a remote coastal location, Mace Head, Ireland, during NAMBLEX." Atmospheric Chemistry and Physics 6, no. 11 (August 9, 2006): 3289–301. http://dx.doi.org/10.5194/acp-6-3289-2006.
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Abstract. A suite of aerosol physical and chemical measurements were made at the Mace Head Atmospheric Research Station, Co. Galway, Ireland, a coastal site on the eastern seaboard of the north Atlantic Ocean during NAMBLEX. The data have been used in this paper to show that over a wide range of aerosol sizes there is no impact of the inter-tidal zone or the surf zone on measurements made at 7 m above ground level or higher. During the measurement period a range of air mass types were observed. During anticyclonic periods and conditions of continental outflow Aitken and accumulation mode were enhanced by a factor of 5 compared to the marine sector, whilst coarse mode particles were enhanced during westerly conditions. Baseline marine conditions were rarely met at Mace Head during NAMBLEX and high wind speeds were observed for brief periods only. The NAMBLEX experiment focussed on a detailed assessment of photochemistry in the marine environment, investigating the linkage between the HOx and the halogen radical cycles. Heterogeneous losses are important in both these cycles. In this paper loss rates of gaseous species to aerosol surfaces were calculated for a range of uptake coefficients. Even when the accommodation coefficient is unity, lifetimes due to heterogeneous loss of less than 10 s were never observed and rarely were they less than 500 s. Diffusional limitation to mass transfer is important in most conditions as the coarse mode is always significant. We calculate a minimum overestimate of 50% in the loss rate if this is neglected and so it should always be considered when calculating loss rates of gaseous species to particle surfaces. HO2 and HOI have accommodation coefficients of around 0.03 and hence we calculate lifetimes due to loss to particle surfaces of 2000 s or greater under the conditions experienced during NAMBLEX. Aerosol composition data collected during this experiment provide representative information on the input aerosol characteristics to western Europe. During NAMBLEX the submicron aerosol was predominately acidified sulphate and organic material, which was most likely internally mixed. The remaining accumulation mode aerosol was sea salt. The organic and sulphate fractions were approximately equally important, though the mass ratio varies considerably between air masses. Mass spectral fingerprints of the organic fraction in polluted conditions are similar to those observed at other locations that are characterised by aged continental aerosol. In marine conditions, the background input of both sulphate and organic aerosol into Europe was observed to be between 0.5 and 1 µg m−3. Key differences in the mass spectra were observed during the few clean periods but were insufficient to ascertain whether these changes reflect differences in the source fingerprint of the organic aerosol. The coarse mode was composed of sea salt and showed significant displacement of chloride by nitrate and to a lesser extent sulphate in polluted conditions.
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Prasetyo, Susiana, and Felicia Yosephine. "MODEL PERPINDAHAN MASSA PADA EKSTRAKSI SAPONIN BIJI TEH DENGAN PELARUT ISOPROPIL ALKHOHOL 50% DENGAN PENGONTAKAN SECARA DISPERSI MENGGUNAKAN ANALISIS DIMENSI." Reaktor 14, no. 2 (October 19, 2012): 87. http://dx.doi.org/10.14710/reaktor.14.2.87-94.
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Indonesia merupakan salah satu penghasil teh terbesar di dunia. Menurut data dari Deptan 2010, dengan luas lahan sebesar 127712 ha, Indonesia dapat menghasilkan produktivitas teh sebesar 153971 ton/tahun. Namun sayangnya, selama ini pemanfaatan tanaman teh di Indonesia masih terbatas pada pucuk daunnya saja. Bagian tanaman teh yang memiliki kandungan potensial namun belum dimanfaatkan adalah biji teh, mengandung 26% saponin, 20-60% minyak dan 11% protein. Saponin merupakan salah satu komponen bioaktif yang telah dimanfaatkan sebagai insektisida pembasmi hama pada tambak udang, bahan baku industri deterjen, shampoo, minuman bir, pembentuk busa pada pemadam kebakaran, dan dapat dimanfaatkan pula sebagai pupuk organik. Pada penelitian ini, saponin biji teh diperoleh melalui ekstraksi biji teh pasca pengepresan menggunakan pelarut IPA 50% secara batch di dalam sebuah ekstraktor berkapasitas 2 L. Pengontakan solvent dengan biji teh dilakukan secara dispersi. Pada penelitian ini, rasio massa pelarut terhadap massa umpan diset 20:1; temperatur divariasikan 25-60 oC, kecepatan pengadukan 100-400 rpm, serta ukuran biji teh divariasikan -40+50 mesh s.d -100+200 mesh. Ekstraksi dilakukan hingga tercapai kesetimbangan. Ekstrak yang diperoleh dipekatkan menggunakan rotavapor vakum pada temperatur di bawah 40oC. Ekstrak pekat saponin kasar yang didapat dimurnikan dengan penambahan eter, etanol dan petroleum eter secara bertahap sehingga diperoleh endapan saponin murni yang kemudian dikeringkan menggunakan tray drier pada temperatur 40oC. Pada penelitian ini, model perpindahan massa sederhana dikembangkan untuk menggambarkan proses ekstraksi padat-cair saponin biji teh. Berdasarkan hasil analisis dimensi diperoleh hubungan antara koefisien perpindahan massa volumetrik (kLa) pada lapisan antar fasa padat-cair dengan variabel-variabel ekstraksi yang dinyatakan dalam persamaan bilangan tak berdimensi dengan ralat rata-rata 3,7904 %.DIMENSIONAL ANALYSIS FOR MASS TRANSFER MODEL FOR SAPONIN FROM TEA SEEDS USING 50% ISOPROPYL ALCOHOL SOLVENT IN A DISPERSION SYSTEM. Indonesia is one of the biggest tea producers in the world. According to the Deptan 2010, about 127712 hectares plantation land area produced 153971 tons of tea. Nevertheless, the utilization of tea is still restricted on the tea young sprouts. The tea seed itself which is very potential due to its bioactive ingredients has not been utilized yet. The seed contains 26% saponin, 20-60% oil, and 11% protein. Saponin is one of the bioactive components which has been used as an insecticide to kill pests on shrimps in the fishing industry, or additives for detergent industry, shampoo, beer drinks, foam on the fire department, and it can also be used as an organic fertilizer. In this research, tea seed saponin was obtained from the extraction of tea seed which was previously mechanically pressed using IPA 50% as the solvent in a 2 L batch extractor. The contact between solvent and the seed tea occurred via dispersion mechanism. The fixed variable during the extractions was mass solvent to mass feed ratios (20:1), while the studied variables were temperatures (25-60oC), stirring speeds (100-400 rpm), and the sizes of the seeds (-40+50 mesh to -100+200 mesh). Extraction was carried out until equilibrium was reached. Extract was concentrated by vacuum evaporation at temperatures below 40oC. Concentrated saponin was purified by sequential addition of ether; ethanol and petroleum ether in order to obtain pure saponin precipitated which is then dried using a tray drier at a temperature of 40oC. In this study, a simple mass transfer model was developed in order to describe the solid-liquid extraction process of tea seed saponin. Based on the results of the dimensional analysis, the relationships between the volumetric mass transfer coefficient (kLa) at the interphase of solid-liquid surface and extraction variables can be expressed by the following equation with the average error is 3.7904%.
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Coe, H., J. D. Allan, M. R. Alfarra, K. N. Bower, M. J. Flynn, G. B. McFiggans, D. O. Topping, et al. "Chemical and physical characteristics of aerosol particles at a remote coastal location, Mace Head, Ireland, during NAMBLEX." Atmospheric Chemistry and Physics Discussions 5, no. 6 (November 14, 2005): 11643–78. http://dx.doi.org/10.5194/acpd-5-11643-2005.
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Abstract. Aerosol number concentrations and size distributions from 3 nm to 20 µm diameter were measured at the Mace Head Atmospheric Research Station, Co. Galway, Ireland, a coastal site on the eastern seaboard of the north Atlantic Ocean. Both on and offline size resolved aerosol composition measurements were also made using an Aerodyne Aerosol Mass Spectrometer (AMS) and ion chromatographic analysis of daily samples collected using a Micro-Orifice Uniform Deposit Impactor (MOUDI). Particle number concentrations, size distributions and AMS measurements were determined at 7 and 22 m above ground level to investigate local effects on the aerosol size distribution induced by the tidal zone. During periods of new particle formation ultrafine particle number concentrations are large and variable, however, outside these periods no variability in particle number was observed at any size, nor was the particle composition variable. Analysis of particle size distributions show that within each air mass observed particle number concentrations were very consistent. During anticyclonic periods and conditions of continental outflow Aitken and accumulation mode were enhanced by a factor of 5 compared to the marine sector, whilst coarse mode particles were enhanced during westerly conditions. Baseline marine conditions were rarely met at Mace Head during NAMBLEX and high wind speeds were observed for brief periods only. Loss rates of gaseous species to aerosol surfaces were calculated for a range of uptake coefficients. Even when the accommodation coefficient is unity, lifetimes of less than 100 s were never observed and rarely were lifetimes less than 500 s. Diffusional limitation to mass transfer is important in most conditions as the coarse mode is always significant, we calculate a minimum overestimate of 50% in the loss rate if this is neglected and so it should always be considered when calculating loss rates of gaseous species to particle surfaces. HO2 and HOI have accommodation coefficients of around 0.03 and hence we calculate lifetimes due to loss to particle surfaces of 2000 s or greater. Aerosol composition measurements using the AMS show accumulation mass modes of acidified sulphate and organic material, both of which have the same shape and are centred at around 350 nm vacuum aerodynamic diameter, implying an internal mixture. The organic and sulphate are approximately equally important, though the mass ratio varies considerably between air masses. Mass spectral fingerprints of the organic fraction in polluted conditions are similar to those observed at other locations that are characterised by aged continental aerosol. Even in marine conditions a background concentration of between 0.5 and 1 µg m−3 of both organic and sulphate was observed. Key differences in the mass spectra were observed during the few clean periods but were insufficient to ascertain whether these changes reflect differences in the source fingerprint of the organic aerosol. However, in an accompanying paper (Dall'Osto et al., 2005) periods of organic dominated aerosol particles were also observed and could be separated from the aged continental aerosol. The coarse mode was composed of sea salt and showed significant displacement of chloride by nitrate and to a lesser extent sulphate in polluted conditions.
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Johnson, D., S. R. Utembe, M. E. Jenkin, R. G. Derwent, G. D. Hayman, M. R. Alfarra, H. Coe, and G. McFiggans. "Simulating regional scale secondary organic aerosol formation during the TORCH 2003 campaign in the southern UK." Atmospheric Chemistry and Physics 6, no. 2 (February 8, 2006): 403–18. http://dx.doi.org/10.5194/acp-6-403-2006.
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Abstract. A photochemical trajectory model has been used to simulate the chemical evolution of air masses arriving at the TORCH field campaign site in the southern UK during late July and August 2003, a period which included a widespread and prolonged photochemical pollution episode. The model incorporates speciated emissions of 124 non-methane anthropogenic VOC and three representative biogenic VOC, coupled with a comprehensive description of the chemistry of their degradation. A representation of the gas/aerosol absorptive partitioning of ca. 2000 oxygenated organic species generated in the Master Chemical Mechanism (MCM v3.1) has been implemented, allowing simulation of the contribution to organic aerosol (OA) made by semi- and non-volatile products of VOC oxidation; emissions of primary organic aerosol (POA) and elemental carbon (EC) are also represented. Simulations of total OA mass concentrations in nine case study events (optimised by comparison with observed hourly-mean mass loadings derived from aerosol mass spectrometry measurements) imply that the OA can be ascribed to three general sources: (i) POA emissions; (ii) a "ubiquitous" background concentration of 0.7 µg m-3; and (iii) gas-to-aerosol transfer of lower volatility products of VOC oxidation generated by the regional scale processing of emitted VOC, but with all partitioning coefficients increased by a species-independent factor of 500. The requirement to scale the partitioning coefficients, and the implied background concentration, are both indicative of the occurrence of chemical processes within the aerosol which allow the oxidised organic species to react by association and/or accretion reactions which generate even lower volatility products, leading to a persistent, non-volatile secondary organic aerosol (SOA). The contribution of secondary organic material to the simulated OA results in significant elevations in the simulated ratio of organic carbon (OC) to EC, compared with the ratio of 1.1 assigned to the emitted components. For the selected case study events, [OC]/[EC] is calculated to lie in the range 2.7-9.8, values which are comparable with the high end of the range reported in the literature.
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Johnson, D., S. R. Utembe, M. E. Jenkin, R. G. Derwent, G. D. Hayman, M. R. Alfarra, H. Coe, and G. McFiggans. "Simulating regional scale secondary organic aerosol formation during the TORCH 2003 campaign in the southern UK." Atmospheric Chemistry and Physics Discussions 5, no. 4 (August 30, 2005): 7829–74. http://dx.doi.org/10.5194/acpd-5-7829-2005.
Full textAbstract:
Abstract. A photochemical trajectory model has been used to simulate the chemical evolution of air masses arriving at the TORCH field campaign site in the southern UK during late July and August 2003, a period which included a widespread and prolonged photochemical pollution episode. The model incorporates speciated emissions of 124 non-methane anthropogenic VOC and three representative biogenic VOC, coupled with a comprehensive description of the chemistry of their degradation. A representation of the gas/aerosol absorptive partitioning of ca. 2000 oxygenated organic species generated in the Master Chemical Mechanism (MCM v3.1) has been developed and implemented, allowing simulation of the contribution to organic aerosol (OA) made by semi- and non-volatile products of VOC oxidation; emissions of primary organic aerosol (POA) and elemental carbon (EC) are also represented. Simulations of total OA mass concentrations in nine case study events (optimised by comparison with observed mass loadings derived from aerosol mass spectrometry measurements) imply that the OA can be ascribed to three general sources: (i) POA emissions; (ii) a ubiquitous background concentration of 0.7 µg m−3; and (iii) gas-to-aerosol transfer of lower volatility products of VOC oxidation generated by the regional scale processing of emitted VOC, but with all partitioning coefficients increased by a species-independent factor of 500. The requirement to scale the partitioning coefficients, and the implied background concentration, are both indicative of the occurrence of chemical processes within the aerosol which allow the oxidised organic species to react by association and/or accretion reactions which generate even lower volatility products, leading to a persistent, non-volatile secondary organic aerosol (SOA). The contribution of secondary organic material to the simulated OA results in significant elevations in the simulated ratio of organic carbon (OC) to EC, compared with the ratio of 1.1 assigned to the emitted components. For the selected case study events, [OC]/[EC] is calculated to lie in the range 2.7–9.8, values which are comparable with the high end of the range reported in the literature.
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Guo, Jianping, Hong Liu, Xi Li, Dahong Xu, and Yihan Zhang. "An Attention Enhanced Spatial–Temporal Graph Convolutional LSTM Network for Action Recognition in Karate." Applied Sciences 11, no. 18 (September 17, 2021): 8641. http://dx.doi.org/10.3390/app11188641.
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With the increasing popularity of artificial intelligence applications, artificial intelligence technology has begun to be applied in competitive sports. These applications have promoted the improvement of athletes’ competitive ability, as well as the fitness of the masses. Human action recognition technology, based on deep learning, has gradually been applied to the analysis of the technical actions of competitive sports athletes, as well as the analysis of tactics. In this paper, a new graph convolution model is proposed. Delaunay’s partitioning algorithm was used to construct a new spatiotemporal topology which can effectively obtain the structural information and spatiotemporal features of athletes’ technical actions. At the same time, the attention mechanism was integrated into the model, and different weight coefficients were assigned to the joints, which significantly improved the accuracy of technical action recognition. First, a comparison between the current state-of-the-art methods was undertaken using the general datasets of Kinect and NTU-RGB + D. The performance of the new algorithm model was slightly improved in comparison to the general dataset. Then, the performance of our algorithm was compared with spatial temporal graph convolutional networks (ST-GCN) for the karate technique action dataset. We found that the accuracy of our algorithm was significantly improved.
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Sutijan, S., Arief Budiman, and Arie Yohanes. "Pengaruh perlakuan daun dan suhu terhadap waktu distilasi pada isolasi minyak cengkeh menggunakan super-steam distillation." Jurnal Teknik Kimia Indonesia 8, no. 2 (October 2, 2018): 69. http://dx.doi.org/10.5614/jtki.2009.8.2.6.
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The effects of leaves treatment and temperature to distillation times in clove oil isolation using super steam distillation Clove oil was generally obtained from clove leaves by using steam distillation. Distillation time was the most important factors in steam distillation as it was proportional to energy cost. In this work, the use of high boiling compound to accelerate steam distillation was studied in which steam distillation was conducted using temperature greater than 100oC. High temperature saturated steam could be obtained by boiling glycerol–water mixture. Glycerol was selected due to its properties in which it was completely water-soluble and high boiling compound. High temperature increased mass transfer of oil in the water within cell tissue of clove leaves, and hence shortened the distillation time. In this work, glycerol concentrations of 0, 10, 25, 50 and 75% by volume were used. The treatment of clove leaves was also investigated. The results showed that glycerol concentration of 10-75% by volum resulted in distillation time reduction of 46–72% compared to conventional steam distillation. For natural clove leaves without treatment, the convective mass transfer coefficient and effective molecular diffusivity were obtained to be 2x10-4 second-1 and 3,6x10-4 m2/second, whereas for chopped leaves these were 8,3x10-3 second-1 and 5,8x10-4 m2/second, respectively.Keywords: Isolation, Clove Oil, Super-Steam Distillation, Glycerol. Abstrak Minyak cengkeh umumnya diproduksi oleh para petani dari daun cengkeh dengan metode steam distillation. Parameter yang paling berpengaruh pada biaya distilasi adalah waktu distilasi, karena waktu distilasi akan berbanding lurus dengan biaya bahan bakar. Penelitian ini bertujuan untuk mempelajari pemakaian super-steam distillation dimana uap air jenuh yang digunakan untuk mendistilasi minyak cengkeh bersuhu lebih tinggi dari titik didih normal air (100oC). Uap jenuh bersuhu tinggi dapat diperoleh dengan mendidihkan campuran air dan gliserol atau pelarut lainnya yang bertitik didih tinggi dan larut sempurna dalam air. Pemakaian uap jenuh bersuhu tinggi akan meningkatkan difusitivitas efektif minyak cengkeh dalam jaringan sel tumbuhan, sehingga akan mempercepat waktu distilasi. Pada penelitian ini digunakan variasi konsentrasi gliserol 0, 10, 25, 50 dan 75% volume. Selain itu juga dipelajari pengaruh pencacahan daun cengkeh sebelum didistilasi. Hasil penelitian menunjukkan bahwa super-steam distillation dengan campuran gliserol dan air dengan perbandingan volum 10-75% mampu memperpendek waktu distilasi sebesar 46-72%. Besarnya nilai koefisien transfer massa dan diffusivitas efektif rerata untuk daun cengkeh tanpa perlakuan adalah 2x10-4 detik-1 dan 3,6x10-4 m2/detik, sedangkan untuk daun dengan pencacahan adalah 8,3x10-3 detik-1 dan 5,8x10-4 m2/detik.Kata Kunci: Isolasi, Minyak Cengkeh, Super-Steam Distillation, Gliserol.
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Zahn, A., P. Franz, C. Bechtel, J. U. Grooß, and T. Röckmann. "Modelling the budget of middle atmospheric water vapour isotopes." Atmospheric Chemistry and Physics 6, no. 8 (June 20, 2006): 2073–90. http://dx.doi.org/10.5194/acp-6-2073-2006.
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Abstract. A one-dimensional chemistry model is applied to study the stable hydrogen (D) and stable oxygen isotope (17O, 18O) composition of water vapour in stratosphere and mesosphere. In the troposphere, this isotope composition is determined by "physical'' fractionation effects, that are phase changes (e.g. during cloud formation), diffusion processes (e.g. during evaporation from the ocean), and mixing of air masses. Due to these processes water vapour entering the stratosphere first shows isotope depletions in D/H relative to ocean water, which are ~5 times of those in 18O/16O, and secondly is mass-dependently fractionated (MDF), i.e. changes in the isotope ratio 17O/16O are ~0.52 times of those of 18O/16O. In contrast, in the stratosphere and mesosphere "chemical'' fractionation mechanisms, that are the production of HO due to the oxidation of methane, re-cycling of H2O via the HOx family, and isotope exchange reactions considerably enhance the isotope ratios in the water vapour imported from the troposphere. The model reasonably predicts overall enhancements of the stable isotope ratios in H2O by up to ~25% for D/H, ~8.5% for 17O/16O, and ~14% for 18O/16O in the mesosphere relative to the tropopause values. The 17O/16O and 18O/16O ratios in H2O are shown to be a measure of the relative fractions of HOx that receive the O atom either from the reservoirs O2 or O3. Throughout the middle atmosphere, MDF O2 is the major donator of oxygen atoms incorporated in OH and HO2 and thus in H2O. In the stratosphere the known mass-independent fractionation (MIF) signal in O3 is in a first step transferred to the NOx family and only in a second step to HOx and H2O. In contrast to CO2, O(1D) only plays a minor role in this MIF transfer. The major uncertainty in our calculation arises from poorly quantified isotope exchange reaction rate coefficients and kinetic isotope fractionation factors.
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Lolli, Simone, Wei Ying Khor, Mohd Zubir Matjafri, and Hwee San Lim. "Monsoon Season Quantitative Assessment of Biomass Burning Clear-Sky Aerosol Radiative Effect at Surface by Ground-Based Lidar Observations in Pulau Pinang, Malaysia in 2014." Remote Sensing 11, no. 22 (November 14, 2019): 2660. http://dx.doi.org/10.3390/rs11222660.
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Direct and indirect aerosol effects are still one of the largest uncertainties related to the Earth energy budget, especially in a wild and remote region like South-East Asia, where ground-based measurements are still difficult and scarce, while endemic cloudy skies make difficult active and passive satellite observations. In this preliminary study, we analyzed and quantitatively assessed the differences between monsoon and inter-monsoon seasons, in terms of radiative effects at surface and columnar heating rate, of clear-sky biomass burning aerosols (no clouds) using ground-based lidar observations obtained with a 355 nm elastic lidar instrument, deployed since 2012 at the Physics Department of Universiti Sains Malaysia (USM). The model-based back-trajectory analysis put in evidence that, during the monsoon seasons (November–March and June–September), the air masses advected towards the observational site transit over active fire hotspot regions, in contrast with the inter-monsoon season. In between the monsoon seasons (April–May, October), the atmosphere over Penang is constituted by local background urban aerosols that originate from road traffic emissions, domestic cooking, and industrial plants emissions. The analysis was carried out using the vertically-resolved profiles of the seasonal averaged aerosol optical properties (monsoon vs. inter-monsoon seasons), e.g., the atmospheric extinction coefficient, to evaluate the seasonal surface aerosol radiative effect and column heating rate differences through the Fu–Liou–Gu (FLG) radiative transfer model. The results put in evidence that the biomass burning advection during the monsoon season (especially during the South West monsoon from June to September) lowers the noon daytime incoming solar shortwave solar radiation reaching the Earth surface with respect to the local background conditions by 91.5 W/m2 (114–69 W/m2). The aerosols also lead to an averaged heating in the first kilometer of the atmosphere of about 4.9 K/day (6.4–3.4 W/m2). The two combined effects, i.e., less absorbed energy by Earth surface and warming of the first kilometer of the boundary layer, increase the low-level stability during monsoon seasons, with a possible reduction in cloud formation and precipitation. The net effect is to exacerbate the haze episodes, as the pollutants rest trapped into the boundary layer. Besides these considerations, the lidar measurements are of great interest in this particular world region and might be used for cal/val of the future space missions, e. g., Earthcare.
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Triwahyudi, Sigit, Bandul Suratmo, Budi Rahardjo, and Leopold Oscar Nelwan. "Pemodelan Matematik Kinerja Pengering Surya Efek Rumah Kaca (ERK)-Hibrid Menggunakan Rak Berputar secara Vertikal (Mathematical Modeling Performance of Greenhouse Effect (GHE)-Hybrid Solar Dryer with a Vertical Rotating Rack)." Jurnal Agritech 36, no. 03 (December 21, 2016): 352. http://dx.doi.org/10.22146/agritech.16608.
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This paper presents a performance test and mathematical modeling of greenhouse effect (GHE)-Hybrid solar dryer with vertical rotating rack. The dryer consists of a greenhouse dryer (1100 × 860 × 1300) mm with eight rack and additional heating system consists of a flat plate collector (1,04 m2), a hot water storage tank (197 liters) and a heat exchanger. To investigate the performance of solar greenhouse dryer, five experimental variation speed of rack were conducted (1, 4, 7, 10 rpm) and without rotation. Materials used in the experiment are local cardamom (Amomum cardamomum Wild). Weight of each experiment about 9 to 10 kg. The average temperature of the hot water storage tank varies from 50.0 to 55.0 °C, drying air temperature between 38.9 to 45.9 °C, while the relative humidity (RH) of drying chamber ranged from 32.1 to 47.4 %. Variation of rotational speed affects on the uniformity of product temperature and water content in each rack drying. At rotation 1 rpm (experiment II), obtained as the best conditions (temperature and moisture content are most uniform). Increasing rotational speed of rack causes increasing in standard deviation of product temperature and moisture content. To simulate the performance of the dryer, mathematical modeling based on heat and mass transfer and a thin layer drying approaches were conducted. Equations solved numerically using the finite difference Euler with Visual Basic Application (VBA) program on Excel. Validation was conducted by comparing the calculation results of mathematical modeling (data prediction) with measurement data (data observation). Criterion validity was determined by the value of the coefficient of determination (R2), the value of RMSD and MAPD. Mathematical models that have been developed can be described precisely the temperature of the hot water storage tank, temperature of the drying chamber, temperature of the product as well as a moisture content decrease. ABSTRAKMakalah ini menyajikan uji unjuk kerja dan pemodelan matematik pengering energi surya (ERK)-Hibrid menggunakan rak berputar secara vertikal. Pengering terdiri dari bangunan rumah kaca berukuran (1100 × 860 × 1300) mm dengan delapan buah rak dan sistim pemanas tambahan yang terdiri dari kolektor plat datar (1,04 m2), tangki penyimpan air panas (197 liter) dan penukar panas. Untuk mengetahuikinerja pengering energi surya, dilakukan lima kali percobaan variasi kecepatan putar rak (1, 4, 7, 10 ) rpm dan tanpa pemutaran rak. Bahan yang dipergunakan pada pengujian adalah kapulaga lokal (Amomum cardamomum Wild). Masing-masing percobaan seberat 9 sampai dengan 10 kg. Rata-rata suhu air tangki penyimpan panas bervariasi dari 50,0 sampai dengan 55,0 °C suhu ruang pengering antara 38,9 sampai dengan 45,9 °C, sedangkan kelembaban relatif (RH) ruang pengering berkisar antara 32,1 sampai dengan 47,4 %. Perlakuan pemutaran rak berpengaruh terhadap keseragaman suhu bahan maupun kadar air pada masing rak pengering. Pada perlakuan pemutaran 1 rpm (percobaan II), didapatkan kondisi terbaik (suhu bahan maupun kadar air yang paling seragam). Dengan kecepatan putar rak yang semakin meningkat menyebabkan nilai ragam suhu bahan maupun kadar air semakin meningkat. Untuk melakukan simulasi unjuk kerja dilakukan pemodelan matematik berdasarkan pindah panas dan massa serta pendekatan pengeringan lapisan tipis. Persamaan diselesaikan secara numerik menggunakan finite difference Euler dengan bantuan bahasa pemrograman Visual Basic Aplication (VBA) Excell. Validasi dilakukan dengan membandingkan antara perhitungan hasil pemodelan (data prediksi) dengan data hasil pengukuran (data observasi). Kriteria kevalidan ditentukan dengan melihat nilai koefisien determinasi (R2), nilai RMSD maupun nilai MAPD. Pemodelan matematik yang telah dibangun dapat menggambarkan dengan tepat perubahan suhu air tangki penyimpan panas, suhu ruang pengering, suhu bahan maupun penurunan kadar air.Kata kunci: Pengering surya efek rumah kaca; uji kinerja; pemodelan matematik Rak berputar vertikal
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Sukatiman, Sukatiman, and Dewanto Harjunowibowo. "PENGARUH POROSITAS BUATAN PADA ADSORBER TERHADAP KUALITAS TRANSFER PANAS DAN MASSA." Jurnal Ilmiah Pendidikan Teknik dan Kejuruan 7, no. 2 (July 29, 2017). http://dx.doi.org/10.20961/jiptek.v7i2.12726.
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<p>On the cooler machine power heat, performance machine efficiency (COP-Coefficient of Performance) is<br />affected by adsorber capacity in adsorbing numbered refrigerant and releasing in fast periode. the velocity will<br />increase if it has velocity transfered heat and high mass.<br />This research focused on knowing variation effect adsorbed of solid porousity adsorber versus head transfer rate<br />and high mass. Research methods used many relevance references.<br />The result of this research is that more increasing porousity volume caused high rate of mass transferred<br />and high heat. Yet if to many porousity made volume of adsorber smaller so that mass transferred achieve optimum<br />and decreased.</p>
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Radifan, Hadyan Hilman, and Lindawati Lindawati. "Pengaruh Kecepatan Alir Udara dan Temperatur Terhadap Perpindahan Massa Padat dan Gas (Disk Naftalen-Udara) Dalam Sistem Kolom Akrilik." Jurnal Rekayasa Hijau 2, no. 3 (December 21, 2018). http://dx.doi.org/10.26760/jrh.v2i3.2515.
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ABSTRAKPerpindahan massa merupakan salah satu fundamental penting yang harus dikuasai oleh seorang sarjana teknik kimia. Sublimasi, adsorbsi, serta pengeringan merupakan salah satu contoh penerapan dari perpindahan massa padat-dan gas di bidang Industri. Tujuan dari penelitian ini adalah untuk mengetahui pengaruh temperatur dan kecepatan udara terhadap koefisien perpindahan massa padat - gas (sistem disk naftalen – udara) dalam sebuah kolom akrilik silinder. Penelitian dilakukan dengan metode observasi. Variasi yang digunakan untuk temperatur adalah 318K; 330K dan 348K dan untuk kecepatan alir udara adalah 1,840 m/s; 3,620 m/s; dan 4,980 m/s. Hasil observasi menunjukkan bahwa peningkatan kecepatan udara dan suhu yang masuk ke dalam sistem kolom akan menyebabkan peningkatan nilai terhadap koefisien perpindahan massa padat-gas (KG).Kata kunci: Perpindahan Massa, Padat-Gas, Temperatur, Kecepatan UdaraABSTRACTMass transfer is one of the fundamental knowledge that must be mastered by a bachelor in chemical engineering. Sublimation, adsorption, and drying are examples of the application of solid-gas mass transfer in the industrial fields. The purpose of this study was to determine the effect of temperature and air velocity on the coefficient of solid - gas mass transfer (disc naphthalene-air system) in a cylindrical acrylic column. The air flow temperature used are 318K; 330K and 348K with the air velocity of 1,840 m/s; 3,620 m/ s; and 4,980 m/s. The research was done by observation method. The observation results show that the increase of air velocity and temperature entering the column system will cause the increase of value to the solid-gas mass transfer coefficient (KG)Keywords: Mass Transfer, Solid- Gas, Temperature, Air Velocity