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.

Biodiesel Preparation from Styrax Confusus Hemsl. Oil Catalyzed by Magnetic Catalyst S2O82--ZrO2/Fe3O4

2013 ◽  
Vol 805-806 ◽  
pp. 247-250
Author(s):  
Zhen Xing Liu ◽  
Xiao An Nie ◽  
Yi Gang Wang
Keyword(s):  
Particle Diameter ◽  
Magnetic Core ◽  
Raw Material ◽  
Bet Surface Area ◽  
Precipitation Method ◽  
Molar Ratio ◽  
Solid Catalyst ◽  
Average Particle ◽  
Magnetic Catalyst ◽  
Catalyst Carrier

Styrax confusus Hemsl., a promising energy plant, was used as raw material for biodiesel preparation in this paper. The transesterification was catalyzed by magnetic catalyst S2O82--ZrO2/Fe3O4, prepared by chemical co-precipitation method. TEM images indicat that the average particle diameter of magnetic core Fe3O4 and catalyst carrier ZrO2/Fe3O4 are 5-20 nm and 30-50 nm respectively. Because of its unique porous structure the BET surface area could up to 140.75 m2/g. The results show that a best catalytic activity is obtained when the solid catalyst impregnated in 2.5 mol·L-1 (NH4)2S2O8, calcined at 400 °C for 3 h, and a high methyl ester yield could be obtained under the optimal reaction conditions of catalyst amount 4.5 % (wt/wt oil), molar ratio of methanol/oil 6:1, reaction temperature 65 °C and time 2.0 h.

The Preparation of TiO2 Film Loaded on Fiberglass Mesh and the Experimental Study on Its Photocatalytic Properties

2010 ◽  
Vol 150-151 ◽  
pp. 1421-1424 ◽  
Author(s):  
Man Wang ◽  
Wei Chen ◽  
Cheng Liu
Keyword(s):  
Humic Acid ◽  
Acid Solution ◽  
Photocatalytic Oxidation ◽  
Degradation Rate ◽  
Sol Gel ◽  
Particle Diameter ◽  
High Photocatalytic Activity ◽  
Solid Particles ◽  
Raw Material ◽  
Average Particle

The TiO2 film loaded on fiberglass mesh was prepared by sol-gel method using butyl titanate as raw material, and the catalyst was characterized by scanning electron microscopy (SEM) and X-ray diffraction(XRD).The catalyst surface of loaded TiO2 can obviously observe solid particles and agglomeration to some extent, the crystalline phase was anatase, and no rutile was observed, the average particle diameter of TiO2 was 40nm,Under the ultraviolet light UV-C irradiation, the photocatalytic oxidation experiments of humic acid solution was conducted. The results showed that the prepared photocatalyst has a high photocatalytic activity, the UV254 degradation rate of humic acid solution in 60min reached 96.9%, but the degradation rate of TOC is only 57.3%, indicating that the organisms in humic acid can not be completely mineralized in photocatalytic oxidation process.

Characterization of Different Brazilian Soils for the Production of Ceramic Artifacts

2021 ◽  
Vol 1017 ◽  
pp. 123-132
Author(s):  
A.R.G. Azevedo ◽  
S.V. Klyuev ◽  
V.A. Klimenko ◽  
M.T. Marvila ◽  
Roman Fediuk
Keyword(s):  
Ceramic Materials ◽  
Raw Material ◽  
Technological Parameters ◽  
Ceramic Blocks ◽  
Physical And Chemical ◽  
Existing Housing ◽  
The City ◽  
Production Industry ◽  
Different Soils

The ceramic materials production industry produces a wide variety of products, such as sealing blocks, roof tiles and shackles, used in civil construction. However, one of the major problems related to the production of these artefacts is the large consumption of natural raw material, which are the clays that are calcined and acquire appropriate technological properties. Brazil is a country that has great prominence in the production of ceramic blocks, used to reduce the existing housing deficit, however the great variability in the characteristics of the soils in the country makes this process very difficult. Thus, the objective of this work was to evaluate the physical and chemical characteristics of four different soils collected in deposits in the city of Campos dos Goytacazes, evaluating right after its technological parameters such as the flexural mechanical strength, water absorption and linear burning retraction of the calcined prismatic specimens at 750, 850 and 1100 °C. The results showed that the collected soils have adequate characteristics for the production of ceramic blocks at a temperature of 1100 °C.

Direct Synthesis of Titanium Nanoparticles by Induction Flow Levitation Technique

2021 ◽  
Vol 887 ◽  
pp. 178-183
Author(s):  
A.N. Markov ◽  
A.V. Vorotyntsev ◽  
A.A. Andronova
Keyword(s):  
High Frequency ◽  
Direct Synthesis ◽  
Particle Diameter ◽  
Average Diameter ◽  
Raw Material ◽  
Average Particle ◽  
Average Particle Diameter ◽  
Metal Sample ◽  
High Particle ◽  
High Frequency Electromagnetic Field

The paper considers the technology of obtaining metal nanoparticles by the method of induction levitation. A bulk metal sample of titanium with a purity of 99.9% and a mass of 0.4 g, which was heated and held in a state of flux levitation by a high-frequency electromagnetic field, was used as the basic raw material for nanoparticles. The obtained nanoparticles were examined using Х-ray diffraction analysis to determine the purity of the product. The analysis showed that it is high. Particle size distribution was investigated using dynamic light scattering, where the average particle diameter is 55 and 47 nm, obtained in Ar and He, respectively. The morphology was studied using scanning electron microscopy, according to which the average diameter of the particles synthesized with He and Ar is 45 and 57 nm, respectively.

The effects of beef carcasses high voltage electrical stimulation and roasting methods on tenderness and water retention of beef

2018 ◽  
Vol 2 (21) ◽  
pp. 103-116
Author(s):  
Katarzyna Tkacz ◽  
Adam Więk ◽  
Ryszard Żywica ◽  
Joanna K. Banach
Keyword(s):  
Heat Treatment ◽  
Electrical Stimulation ◽  
Water Content ◽  
High Voltage ◽  
Raw Material ◽  
Beef Carcasses ◽  
Maximum Shear Force ◽  
Negative Effect ◽  
Forced Air ◽  
Air Circulation

The aim of the study was to determine the effect of high voltage electrical stimulation (330 V, 17 Hz, 120 s) of beef half-carcass and heat treatment on tenderness and water holding capacity of meat. The experimental material was a semimembranosus muscle derived from Polish Holstein-Friesian heifers (n=12). In the experiment, a forced and natural air circulation ovens were used; the raw material was heated at 170ºC to obtain a final temperature from 55 to 80ºC inside the beef. Results showed that electrical stimulation improved tenderness of roasted beef, which was demonstrated in the decrease in the maximum shear force from 39 to 26%. The electrical stimulation had a negative effect on cooking losses during roasting and water content in the final product. It has also been shown that studied quality attributes of beef depends on the type of heat treatment. Beef prepared in forced air circulation oven, were characterized by lower water content and higher values of maximum shear and compression forces than those heated in natural air circulation oven.

Use of the Processed Waste from Kaolin and Granite Sawing in the Manufacture of Tubular Ceramic Membranes

2014 ◽  
Vol 805 ◽  
pp. 337-342 ◽  
Author(s):  
Alexsandra Cristina Chaves ◽  
Gelmires Araújo Neves ◽  
Hélio Lucena Lira ◽  
Danielle Nascimento Silva Oliveira ◽  
Ana M.G.D. Mendonça
Keyword(s):  
Particle Size ◽  
Mercury Porosimetry ◽  
Particle Diameter ◽  
Ceramic Membranes ◽  
Raw Material ◽  
Average Particle ◽  
Average Pore ◽  
X Ray ◽  
Ceramic Mass ◽  
Indiscriminate Disposal

The incorporation of waste from various industrial activities in ceramic products comes as a technological alternative to reduce the environmental impacts caused by the indiscriminate disposal of wastes in the environment. The kaolin and granite processing industries have been mentioned as sources of contamination and pollution, due to the enormous amounts of wastes they produce. The use of these wastes as raw material and its transformation into products that can be commercialized and/or show economic viability, presents as an alternative to the industries. The aim of this work was to use ceramic masses incorporated with kaolin waste (35%), granite (35%) and bentonite (30%) for the confection of tubular ceramic membranes using extrusion as production process. The ceramic mass was characterized through analysis techniques of thermogravimetric, chemical, particle size and X-ray. The membranes produced, after sintering in temperatures of 850, 900, 950 and 1000oC, were submitted to characterizations of scanning electron microscopy, mercury porosimetry and permeability test by tangential flow. The preliminary result of the particle size analyses identified that the ceramic mass presents an average particle diameter of 37.00μm. The membranes presented porosity of approximately 32%, and average pore diameter within the ultrafiltration range.

Adsorption of safranine T from aqueous medium by nano mesoporous MCM-41: adsorption equilibrium, kinetics, and thermodynamics

2020 ◽  
Vol 10 ◽  
Author(s):  
Xiao-Dong Li ◽  
Qing-Zhou Zhai
Keyword(s):  
Electron Microscopy ◽  
Ph Value ◽  
Particle Diameter ◽  
Spherical Particles ◽  
Practical Significance ◽  
Average Particle ◽  
Average Pore ◽  
Kinetics And Thermodynamics ◽  
Safranine T ◽  
Mcm 41

Introduction: In industrial production, a small amount of saffron T emissions will cause increase of water color and increase of chemical oxygen consumption, so study of the decolorization of saffron T wastewater has an important practical significance. Methods: MCM (Mobil Composition of Matter)-41 molecular sieve was synthesized by hydrothermal method. Power Xray diffraction and scanning electron microscopy were used to characterize the sample. Safranine T dye was adsorbed from water by the MCM-41 prepared. Kinetics and thermodynamics of the adsorption were studied. Results: The MCM-41 sample presented spherical particles and regular. The BET (Brunner-Emmett-Teller) specific surface area of the sample determined by 77 K low temperature nitrogen adsorption-desorption isotherm was 932 m2 /g. Its average particle diameter was 110 nm. TEM (transmission electron microscopy) results showed that the sample structure presented a honeycomb pore structure and the average pore diameter was 3.0 nm. The results showed that when room temperature was 20 ± 1 ℃, adsorbate safranine T: adsorbent MCM-41 = 20 : 1，the optimum pH value of adsorption was 4.0 and contact time was 20 min, the adsorption rate reached 98.29% and the adsorption capacity was 19.66 mg/g. The entropy change and enthalpy change of the adsorption system are respectively ΔS0 = 157.5 J/(mol·K); ΔH0 = 21.544 kJ/mol. When temperature was 277.15, 293.15, 303.15 K，the free energy change was respectively △G1 0 = -22.107 kJ/mol, △G2 0 = -24.627 kJ/mol, △G3 0 = -26.202 kJ/mol. Conclusion: The adsorption of safranine T by MCM-41 belongs to a pseudo-second-order adsorption. This adsorption accords with the Freundlich equation and belongs to a heterogeneous adsorption. The adsorption is an endothermic reaction of entropy increase, being spontaneous.

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 A Comparative Evaluation of Nanohydroxyapatite-Enriched Hydrogen Peroxide Home Bleaching System on Color, Hardness and Microstructure of Dental Enamel

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3072
Author(s):  
Riccardo Monterubbianesi ◽  
Vincenzo Tosco ◽  
Tiziano Bellezze ◽  
Giampaolo Giuliani ◽  
Mutlu Özcan ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Particle Diameter ◽  
Dental Enamel ◽  
Sem Analysis ◽  
Control Group ◽  
Average Particle ◽  
Color Analysis ◽  
Enamel Microstructure ◽  
Prismatic Structure ◽  
20 Nm

This study aimed to evaluate two hydrogen peroxide (HP)-based at-home bleaching systems in order to analyze whether nano-hydroxyapatite (nHA) addition may represent a reliable and safe solution for tooth whitening without altering dental microstructure and hardness. Human third molars (N = 15) were treated with two bleaching agents, one containing 6%HP (6HP) and the other 6% HP nHA-enriched (6HP-nHA) with average particle diameter ranging from 5–20 nm. Their effects on enamel were assessed using a spectrophotometer, Vickers microhardness (VMH) test and Scanning Electron Microscopy (SEM), comparing the treated groups with the non-treated control group (CTR). Color analysis revealed improvement in whiteness in both groups compared to CTR. VMH test results showed no differences among the groups. SEM analysis highlighted no evident changes in the enamel microstructure of tested groups compared to CTR. At high magnification, in 6HP group, a slight increase in irregularities of enamel surface morphology was observed, while 6HP-nHA group displayed removal of the aprismatic layer but preservation of the intact prismatic structure. These results suggest that the 6HP-nHA agent may be recommended to provide reliable whitening treatment, without damaging the enamel micromorphology and hardness.

An Efficient Immersed Boundary Method Based on Penalized Direct Forcing for Simulating Flows Through Real Porous Media

2012 ◽  
Author(s):  
Wim-Paul Breugem ◽  
Vincent van Dijk ◽  
René Delfos
Keyword(s):  
Porous Medium ◽  
Ct Scan ◽  
Immersed Boundary Method ◽  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Particle Diameter ◽  
Immersed Boundary ◽  
Average Particle ◽  
Boundary Method ◽  
Direct Forcing

A computationally efficient Immersed Boundary Method (IBM) based on penalized direct forcing was employed to determine the permeability of a real porous medium. The porous medium was composed of about 9000 glass beads with an average particle diameter of 1.93 mm and a porosity of 0.367. The forcing of the IBM depends on the local solid volume fraction within a computational grid cell. The latter could be obtained from a high-resolution X-ray Computed Tomography (CT) scan of the packing. An experimental facility was built to determine the permeability of the packing experimentally. Numerical simulations were performed for the same packing based on the data from the CT scan. For a scan resolution of 0.1 mm the numerical value for the permeability was nearly 70% larger than the experimental value. An error analysis indicated that the scan resolution of 0.1 mm was too coarse for this packing.

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