Experimental study of a humidification-dehumidification solar technique by natural and forced air circulation

Energy ◽  
2014 ◽  
Vol 68 ◽  
pp. 218-228 ◽  
Author(s):  
A.E. Kabeel ◽  
Mofreh H. Hamed ◽  
Z.M. Omara ◽  
S.W. Sharshir
Keyword(s):  
Experimental Study ◽  
Forced Air ◽  
Air Circulation

scholarly journals Air circulation in a gastrointestinal light source box and endoscope in the era of SARS-CoV-2 and airborne transmission of microorganisms

2021 ◽  
Vol 09 (03) ◽  
pp. E482-E486
Author(s):  
Stanislas Chaussade ◽  
Einas Abou Ali ◽  
Rachel Hallit ◽  
Arthur Belle ◽  
Maximilien Barret ◽  
...  
Keyword(s):  
Light Source ◽  
Cooling System ◽  
Air Cooling ◽  
Airborne Transmission ◽  
Plastic Tube ◽  
Care Workers ◽  
Air Cooling System ◽  
Forced Air ◽  
Air Circulation ◽  
Closed Environment

Abstract Background and study aims The role that air circulation through a gastrointestinal endoscopy system plays in airborne transmission of microorganisms has never been investigated. The aim of this study was to explore the potential risk of transmission and potential improvements in the system. Methods We investigated and described air circulation into gastrointestinal endoscopes from Fujifilm, Olympus, and Pentax. Results The light source box contains a lamp, either Xenon or LED. The temperature of the light is high and is regulated by a forced-air cooling system to maintain a stable temperature in the middle of the box. The air used by the forced-air cooling system is sucked from the closed environment of the patient through an aeration port, located close to the light source and evacuated out of the box by one or two ventilators. No filter exists to avoid dispersion of particles outside the processor box. The light source box also contains an insufflation air pump. The air is sucked from the light source box through one or two holes in the air pump and pushed from the air pump into the air pipe of the endoscope through a plastic tube. Because the air pump does not have a dedicated HEPA filter, transmission of microorganisms cannot be excluded. Conclusions Changes are necessary to prevent airborne transmission. Exclusive use of an external CO2 pump and wrapping the endoscope platform with a plastic film will limit scatter of microorganisms. In the era of pandemic virus with airborne transmission, improvements in gastrointestinal ventilation systems are necessary to avoid contamination of patients and health care workers.

scholarly journals Mathematical modeling and determination of thermodynamic properties of jabuticaba peel during the drying process

2016 ◽  
Vol 20 (6) ◽  
pp. 576-580 ◽  
Author(s):  
Cristian F. Costa ◽  
Paulo C. Corrêa ◽  
Jaime D. B. Vanegas ◽  
Fernanda M. Baptestini ◽  
Renata C. Campos ◽  
...  
Keyword(s):  
Experimental Data ◽  
Thermodynamic Properties ◽  
Drying Process ◽  
Drying Temperature ◽  
Air Temperatures ◽  
Nutritional Qualities ◽  
Forced Air ◽  
Air Circulation ◽  
Best Fit

ABSTRACT Jabuticaba is a fruit native of Brazil and, besides containing many nutritional qualities, it also has a good field for use in products such as flour for cakes and biscuits, juice, liqueur, jelly and others. This study aimed to model the drying kinetics and determine the thermodynamic properties of jabuticaba peel at different drying air temperatures. Ripe fruits of jabuticaba (Myrciaria jaboticaba) were collected and pulped manually. Drying was carried out in a forced-air circulation oven with a flow of 5.6 m s-1 at temperatures of 40, 50, 60 and 70 °C. Six mathematical models commonly used to represent the drying process of agricultural products were fitted to the experimental data. The Arrhenius model was used to represent the drying constant as a function of temperature. The Midilli model showed the best fit to the experimental data of drying. The drying constant increased with the increment in drying temperature and promoted an activation energy of 37.29 kJ mol-1. Enthalpy and Gibbs free energy decreased with the increase in drying temperature, while entropy decreased and was negative.

scholarly journals Industrial Ceramic Blocks for Buildings: Clay Characterization and Drying Experimental Study

Energies ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2834
Author(s):  
A.M. Vasconcelos da Silva ◽  
J.M.P.Q. Delgado ◽  
A.S. Guimarães ◽  
W.M.P. Barbosa de Lima ◽  
R. Soares Gomez ◽  
...  
Keyword(s):  
Mass Loss ◽  
Particle Diameter ◽  
Ceramic Materials ◽  
Raw Material ◽  
Average Particle ◽  
Ceramic Block ◽  
Ceramic Blocks ◽  
Dimensional Variation ◽  
Forced Air ◽  
Air Circulation

The conformation of a ceramic piece follows the steps of preparing the raw material, molding, lamination, drying, and firing. Drying is a thermodynamic process of heat and mass transfer, with dimensional variations of the product that requires a large amount of energy. Ceramic materials when exposed to non-uniform drying may suffer cracks and deformations, reducing their post-drying quality. Thus, this work aimed to study the drying of industrial ceramic blocks in an oven with forced air circulation. Experiments were carried out to characterize the clay and drying of the ceramic block at temperatures ranging from 50 °C to 100 °C. Results of the chemical, mineralogical, granulometric, differential thermal, and thermogravimetric analysis of the clay, and heating kinetics, mass loss, and dimensional variation of the industrial ceramic block are presented and analyzed in detail. It was found that the clay is basically composed of silica and alumina (≈ 80.96%), with an average particle diameter of 13.36 μm. The study proved that drying at high temperature and low relative humidity of the air generates high rates of mass loss, heating, and volumetric shrinkage in the ceramic product, and high thermo-hydraulic stresses, which cause the appearance and propagation of cracks, gaps, and cleavages, compromising the final quality of the product.

scholarly journals Extraction and Simultaneous Determination of Glyphosate, AMPA and Compounds of the Shikimic Acid Pathway in Plants

2015 ◽  
Vol 33 (2) ◽  
pp. 295-304 ◽  
Author(s):  
G.L.G.C. Gomes ◽  
C.A. Carbonari ◽  
E.D. Velini ◽  
M.L.B. Trindade ◽  
J.R.M. Silva
Keyword(s):  
Mass Spectrometry ◽  
Shikimic Acid ◽  
Quinic Acid ◽  
Saccharum Officinarum ◽  
Joint Analysis ◽  
Aminomethylphosphonic Acid ◽  
Water Ph ◽  
Acid Pathway ◽  
Forced Air ◽  
Air Circulation

This study has aimed to develop a method for simultaneous extraction and determination by liquid chromatography and mass spectrometry (LC-MS/MS) of glyphosate, aminomethylphosphonic acid (AMPA), shikimic acid, quinic acid, phenylalanine, tyrosine and tryptophan. For the joint analysis of these compounds the best conditions of ionization in mass spectrometry and for chromatographic separation of the compounds were selected. Calibration curves and linearity ranges were also determined for each compound. Different extraction systems of the compounds were tested from plant tissues collected from sugarcane (Saccharum officinarum) and eucalyptus (Eucalyptus urophylla platiphylla) plants two days after the glyphosate application at the dose of 720 g a.e. ha-1. The plant material was dried in a forced air circulation drying oven and in a lyophilizer, and subsequently the extractions with acidified water (pH 2.5), acetonitrile-water (50:50) [v/v] and methanol-water (50:50) [v/v] were tested. To verify the recovery of the compounds in the plant matrix with acidified water as an extracting solution, the samples were fortified with a solution containing the mixture of the different analytical standards present so that this one presented the same levels of 50 and 100 μg L-1 of each compound. All experiments were conducted with three replicates. The analytical method developed was efficient for compounds quantifications. The extraction from the samples dried in an oven and using acidified water allowed better extraction levels for all compounds. The recovery levels of the compounds in the fortified samples with known amounts of each compound for both plants samples were rather satisfactory.

scholarly journals Effect of drying, pelliculation and storage on the physiological quality of eggplant seeds

2014 ◽  
Vol 36 (2) ◽  
pp. 240-245 ◽  
Author(s):  
Natassia Zamariola ◽  
João Almir Oliveira ◽  
Luiz Antônio Augusto Gomes ◽  
Michelle Fonseca Jácome ◽  
Leandro Vilela Reis
Keyword(s):  
Seed Quality ◽  
Seedling Emergence ◽  
Film Coating ◽  
Germination Percentage ◽  
Hybrid Seeds ◽  
Physiological Quality ◽  
Forced Air ◽  
Air Circulation ◽  
And Storage

The use of methods and technologies such as drying and film coating can bring significant contributions to the farmer. This experiment was conducted in order to evaluate the effect of drying and film coating on the physiological quality of eggplant seeds during storage. Hybrid seeds UGA MS1 produced by the company Hortiagro - Ijaci, MG were used. Seeds were subjected to two types of drying: slow (room temperature) and quick (oven with forced air circulation at 35 ºC). The chemical treatment was performed with the Captan product at a dose of 250 grams per 100 kilograms of seed and for the recoating were used three doses of polymer: (0, 3 and 6 mL.kg-1 of seeds). The physiological quality of seeds was evaluated every three months until reaching the period of nine months using germination test, seedling emergence test and seedling establishment. There is a reduction of physiological seed quality during the storage. The slow drying of eggplant seeds results in better quality seeds. The use of polymer reduces the germination percentage, germination speed index and the percentage of seedling emergence.

scholarly journals Processamento do tomate (lycopersicumexculentum) seco com substituição do cloreto de sódio pelo cloreto de potássio: estudo da avaliação da desidratação osmótica seguida de secagem

2018 ◽  
Vol 1 (40) ◽  
pp. 35
Author(s):  
George Nóbrega Wagner ◽  
Bruno Araújo Alexandre ◽  
Edilene Santos Vieira ◽  
Maiane Barbosa Silva ◽  
Karoline Oliveira Santos ◽  
...  
Keyword(s):  
Citric Acid ◽  
Water Loss ◽  
Physicochemical Parameters ◽  
Osmotic Dehydration ◽  
Drying Time ◽  
Physical Chemical ◽  
Physico Chemical ◽  
Tomato Processing ◽  
Forced Air ◽  
Air Circulation

<p>The objective of this work was to evaluate the osmotic dehydration (OD), with the substitution of sodium chloride (NaCl) by potassium chloride (KCl), followed by the drying, in dry tomato processing. Italian -tomatoes were collected . After the selection, homogenization and sanitization, samples were taken from the tomato in natura for the physical-chemical analysis. Then, 13 (thirteen) solutions of Sucrose, NaCl and KCl in their different combinations were used in OD. After that, samples of the 13 treatments were collected for physico-chemical determinations and variables of weight loss (PP) and water loss (PA). Subsequently, all treatments were submitted to oven drying with forced air circulation at 60 ° C for 17 hours. After the drying, the treatments that presented final moisture of not more than 25% were selected for analysis of the physicochemical parameters. All the analyzes followed the technical norms established by the Adolfo Lutz Institute. The results of the in natura fruit presented values of 95.68% of humidity; 0.28 ATT expressed as citric acid; 3.84 pH and 4.75 ° Brix. After the DO of the 13 treatments, the tomatoes showed variations of 90.76 to 95.19% of humidity; 0.24 to 0.36 ATT expressed as citric acid; 3.46 to 4.28 pH and 4 to 7.1 of Brix. As for the initial and final OD mass, it has been verified that the percentages of water loss and weight present significant values in T6, T8 and T12 treatments . Partial or total substitution of NaCl by KCl in the amounts of 5 and 10% studied in the osmotic process demonstrates efficiency in the reduction of the drying time to obtain the desired moisture when compared to the treatments in which there is no introduction of KCl. Therefore, the use of KCl as a partial or total substitute for NaCl in the osmotic dehydration of tomato is considered tefficient in drying.Palavras-chave: Perda de água, secagem, redução de sódio, saúde.</p>

scholarly journals INFLUENCE OF DRYING ON THE PHYSICAL AND MECHANICAL PROPERTIES OF WOOD FROM TREES GROWN IN AN AGROFORESTRY SYSTEM

2020 ◽  
Vol 44 ◽  
Author(s):  
Elder Eloy ◽  
Eduarda Bandera ◽  
Tauana Mangini ◽  
Laura da Silva Zanchetta ◽  
Rômulo Trevisan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Eucalyptus Grandis ◽  
Physical And Mechanical Properties ◽  
Agroforestry System ◽  
Bending Test ◽  
Schizolobium Parahyba ◽  
Standard Specimens ◽  
Forced Air ◽  
Air Circulation

ABSTRACT The cultivation of native and exotic species intercropped in an agroforestry system raises the interest for information on the properties of wood. Therefore, different methods are being tested to improve the technological properties of this material, including drying, which causes changes in the physical and mechanical properties of the wood. The present study investigated the influence of drying on the physical and mechanical properties of wood from tree species grown in an agroforestry system. Parapiptadenia rigida (Benth.) Brenan, Peltophorum dubium (Spreng.) Taub., Eucalyptus grandis W. Hill × Eucalyptus urophylla S.T. Blake (hybrid), and Schizolobium parahyba (Vell.) S.F.Blake were the species selected for the study. Three 9-year-old individuals of each of the species were obtained from an agroforestry system. Thirty wood samples (2.5 × 2.5 × 41 cm) were extracted from each species. The wood samples were divided between temperature treatments; 6 samples were used for each heat treatment (control, 120, 150, 180, and 210 °C), which were then dried for two hours in an oven (with forced air circulation). Following the heat treatment, the mechanical properties of wood samples were evaluated to determine the modulus of elasticity and rupture, the tension in the proportional limit, and maximum force according to the ASTM D-143-94 (2000) standard. Finally, the physical properties of the retractability of the wood samples were evaluated according to the NBR 7190 (ABNT, 1997) standard. Specimens used to analyze this variable came from sections of the wood (sample dimensions: 2.5 × 2.5 × 5 cm) not affected by the static bending test. Our findings indicate that, for all species investigated in this study, drying alters the physical and mechanical properties of the wood, with the most significant changes occurring at temperatures between 120 and 180 °C.

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