scholarly journals Parametric study of glycerol and contaminants removal from biodiesel through solvent-aided crystallization

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Mohd. Afnan Ahmad ◽  
Arun Letchumanan ◽  
Shafirah Samsuri ◽  
Wan Nur Athirah Mazli ◽  
Juniza Md Saad
Keyword(s):  
Organic Compounds ◽  
Parametric Study ◽  
Crystallization Process ◽  
International Standards ◽  
Coolant Temperature ◽  
Crystallization Time ◽  
Time Result ◽  
Biodiesel Quality ◽  
Contaminants Removal ◽  
Temperature Crystallization

AbstractAt present, biodiesel is known as an alternative fuel globally. It is also known that the purification of biodiesel before consumption is mandatory to comply with international standards. Commonly, purification using water washing generates a massive amount of wastewater with a high content of organic compounds that can harm the environment. Therefore, this study applied and tested a waterless method, i.e., the solvent-aided crystallization (SAC), to remove glycerol and other traces of impurities in the crude biodiesel. The parameters of coolant temperature, crystallization time, and stirring rate on the SAC system were investigated. It was discovered that with 14 °C coolant temperature, 300 RPM and higher cooling time result in the highest percentage of FAME up to 99.54%, which indicates that contaminants' presence is limited in the purified biodiesel. The use of 1-butanol as the solvent for crystallization process remarkably enhanced the separation and improved the higher biodiesel quality.

scholarly journals Investigations of Museum Indoor Microclimate and Air Quality. Case Study from Romania

Atmosphere ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 286
Author(s):  
Dorina Camelia Ilieș ◽  
Florin Marcu ◽  
Tudor Caciora ◽  
Liliana Indrie ◽  
Alexandru Ilieș ◽  
...  
Keyword(s):  
Air Quality ◽  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Construction Materials ◽  
International Standards ◽  
Total Volatile ◽  
Negative Effects ◽  
Museum Exhibits ◽  
Volatile Organic ◽  
Total Volatile Organic Compounds

Poor air quality inside museums is one of the main causes influencing the state of conservation of exhibits. Even if they are mostly placed in a controlled environment because of their construction materials, the exhibits can be very vulnerable to the influence of the internal microclimate. As a consequence, museum exhibits must be protected from potential negative effects. In order to prevent and stop the process of damage of the exhibits, monitoring the main parameters of the microclimate (especially temperature, humidity, and brightness) and keeping them in strict values is extremely important. The present study refers to the investigations and analysis of air quality inside a museum, located in a heritage building, from Romania. The paper focuses on monitoring and analysing temperature of air and walls, relative humidity (RH), CO2, brightness and particulate matters (PM), formaldehyde (HCHO), and total volatile organic compounds (TVOC). The monitoring was carried out in the Summer–Autumn 2020 Campaign, in two different exhibition areas (first floor and basement) and the main warehouse where the exhibits are kept and restored. The analyses aimed both at highlighting the hazard induced by the poor air quality inside the museum that the exhibits face. The results show that this environment is potentially harmful to both exposed items and people. Therefore, the number of days in which the ideal conditions in terms of temperature and RH are met are quite few, the concentration of suspended particles, formaldehyde, and total volatile organic compounds often exceed the limit allowed by the international standards in force. The results represent the basis for the development and implementation of strategies for long-term conservation of exhibits and to ensure a clean environment for employees, restorers, and visitors.

Crystallization of Tin-Implanted Amorphous Silicon Thin Films

1992 ◽  
Vol 279 ◽  
Author(s):  
Fuyu Lin ◽  
Miltiadis K. Hatalis
Keyword(s):  
Amorphous Silicon ◽  
Crystallization Process ◽  
Silicon Films ◽  
Grain Structure ◽  
Crystallization Time ◽  
Silicon Thin Films ◽  
Fine Grain ◽  
Annealing Conditions ◽  
Transmission Electron ◽  
Si Films

ABSTRACTThe crystallization of Sn-implanted amorphous silicon was studied as a function of tin implant dose and annealing conditions by transmission electron microscopy. The films were implanted at an energy of 110 keV with a dose in the range of 5 × 1014 to 5×1016 cm−2 and were annealed at a temperature in the range of 450°C to 550°C. An enhanced rate of crystallization in amorphous Si-Sn films compared to the non-implanted amorphous silicon films during thermal annealing was observed. The crystallization process of Si films implanted with tin at a dose of 2.5×1016 cm−2 or less is very similar to unimplanted silicon films except higher nucleation rates and shorter crystallization time were observed with increasing tin dose. Films implanted with tin at a dose of 2.5×1016 cm−2 or more display extremely rapid crystallization (3 hours at 450°C) and very fine grain structure (10 nm); no substantial grain growth has been observed during lurther annealing, but some single crystal-like areas were formed. In-situ annealing of silicon implanted to 5×1016 cm−2 showed that the crystallization process is enhanced by the formation of the liquid tin phase.

Improved calcium sulfate recovery from a reverse osmosis retentate using eutectic freeze crystallization

2013 ◽  
Vol 67 (1) ◽  
pp. 139-146 ◽  
Author(s):  
D. G. Randall ◽  
R. Mohamed ◽  
J. Nathoo ◽  
H. Rossenrode ◽  
A. E. Lewis
Keyword(s):  
Low Temperature ◽  
Reverse Osmosis ◽  
Calcium Sulfate ◽  
Crystallization Process ◽  
Eutectic Temperature ◽  
Water Recovery ◽  
Recovery Rates ◽  
Low Temperature Crystallization ◽  
Operating Temperatures ◽  
Temperature Crystallization

A novel low temperature crystallization process called eutectic freeze crystallization (EFC) can produce both salt(s) and ice from a reverse osmosis (RO) stream by operating at the eutectic temperature of a solution. The EFC reject stream, which is de-supersaturated with respect to the scaling component, can subsequently be recycled back to the RO process for increased water recovery. This paper looks at the feasibility of using EFC to remove calcium sulfate from an RO retentate stream and compares the results to recovery rates at 0 and 20 °C. The results showed that there was a greater yield of calcium sulfate obtained at 0 °C as compared with 20 °C. Operation under eutectic conditions, with only a 20% ice recovery, resulted in an even greater yield of calcium sulfate (48%) when compared with yields obtained at operating temperatures of 0 and 20 °C (15% at 0 °C and 13% at 20 °C). The theoretical calcium recoveries were found to be 75 and 70% at 0 and 20 °C respectively which was higher than the experimentally determined values. The EFC process has the added advantage of producing water along with a salt.

Hydrothermal Synthesis of Na-LTA, Na-X and HS Zeolites from Tunisian Sand and Aluminum Scraps

2010 ◽  
Vol 636-637 ◽  
pp. 1389-1396 ◽  
Author(s):  
Hassib Tounsi ◽  
Samir Mseddi ◽  
Samir Djemal
Keyword(s):  
Hydrothermal Synthesis ◽  
Physicochemical Parameters ◽  
Crystallization Time ◽  
Naoh Solution ◽  
Temperature Crystallization

Na-LTA, Na-X and HS zeolites have been prepared from Tunisian sand and aluminum scraps. The alkaline attack of the sand leads to the metasilicate sol used as a source of silica. The aluminum source was prepared by dissolving aluminum in NaOH solution. The influence of several physicochemical parameters such as temperature, crystallization time and the alkalinity of the reaction mixture on the nature and the purity of the obtained products have been investigated.

scholarly journals Parametric study of dilute alloy crystallization process

2019 ◽  
pp. 1-30
Author(s):  
Andrey Olegovich Gusev ◽  
Olga Vladimirovna Shcheritsa ◽  
Olga Semenovna Mazhorova
Keyword(s):  
Parametric Study ◽  
Crystallization Process ◽  
Dilute Alloy

Suppressing the Supercooling Effect of Erythritol by Bubbling for Latent Heat Storage

2020 ◽  
Author(s):  
Sheng Yang ◽  
Xue-Feng Shao ◽  
Li-Wu Fan
Keyword(s):  
Latent Heat ◽  
Flow Rate ◽  
Crystallization Process ◽  
Heat Storage ◽  
Crystallization Time ◽  
High Chemical ◽  
Latent Heat Storage ◽  
Medium Temperature ◽  
Bubble Sizes ◽  
Change Material

Abstract Erythritol, a phase change material (PCM) pertinent to the medium temperature range latent heat storage applications, has the advantages of large storage density, non-toxicity, and high chemical compatibility, but it also suffers from serious supercooling upon cool-down to release the stored heat. In this work, the bubbling method was attempted as an economic and easy way to suppress the supercooling effect of erythritol. At a flow rate of 300 mL/min, N2 bubbles of the size of about 4.4 mm in diameter were continuously introduced into molten erythritol under various subcooling temperatures of ΔTsub = 30, 40, 50, 60, and 95 °C. At the same flow rate, slightly larger bubbles of about 6 mm in diameter were also tested as a contrast case at a single subcooling temperature of ΔTsub = 30°C. The presence of the bubbles was clearly exhibited to successfully facilitate crystallization process of erythritol. It was shown that when ΔTsub = 40, 50, 60, and 95 °C, the introduction of N2 bubbles can reduce the nucleation temperatures Tn by 7.0, 8.2, 10.0 and 5.7°C, respectively, and shorten the crystallization time tc by 19.7%, 14.8%, 13.8%, and 6.4%, respectively. At the lowest subcooling of ΔTsub = 30 °C, erythritol cannot crystallize without the presence of bubbles. The size of the bubbles was found to have negligible effect as the complete crystallization time remains almost the same with the two bubble sizes.

Copper-Enhanced Solid Phase Crystallization of Amorphous Silicon Films

1996 ◽  
Vol 424 ◽  
Author(s):  
Dong Kyun Sohn ◽  
Dae Gyu Moon ◽  
Byung Tae Ahn
Keyword(s):  
Solid Phase ◽  
Copper Ions ◽  
Crystallization Time ◽  
Solid Phase Crystallization ◽  
New Process ◽  
Low Temperature Crystallization ◽  
Amorphous Si ◽  
Si Films ◽  
Fractal Size ◽  
Temperature Crystallization

AbstractLow-temperature crystallization of amorphous Si (a-Si) films was investigated by adsorbing copper ions on the surface of the films. The copper ions were adsorbed by spincoating of Cu solution. This new process lowered the crystallization temperature and reduced crystallization time of a-Si films. For 1000 ppm solution, the a-Si film was partly crystallized down to 500°C in 20 h and almost completely crystallized at 530°C in 20 h. The adsorbed Cu on the surface acted as a seed of crystalline and caused fractal growth. The fractal size was varied from 10 to 200 prm, depending on the Cu concentration in solution. But the grain size of the films was about 400 nm, which was similar to that of intrinsic films crystallized at 600°C.

Synthesis and Characterization of Small Crystals NaY Zeolite with High Silicon

2012 ◽  
Vol 554-556 ◽  
pp. 81-88 ◽  
Author(s):  
Qing Yan Cui ◽  
Ya Song Zhou ◽  
Qiang Wei
Keyword(s):  
Low Temperature ◽  
Crystal Size ◽  
High Surface ◽  
Crystallization Time ◽  
Organic Additives ◽  
Nay Zeolite ◽  
Small Crystals ◽  
Low Temperature Crystallization ◽  
High Silicon ◽  
Temperature Crystallization

Small crystals NaY zeolite with high silicon was successfully synthesized via a two-stage temperature crystallization program, without adding any organic additives. While the effect of low temperature crystallization time and the alkalinity on the crystal size and SiO2/Al2O3 ratio of NaY zeolite were investigated. The as-synthesized samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier Transform Infrared (FT-IR) spectroscopy, N2 adsorption, 29Si MAS NMR and thermogravimetric TG measurements. NaY zeolite, with crystal size about 100 nm and SiO2/Al2O3 ratio about 5.3, is obtained. It possesses high surface area and some amount of mecropores, and the decomposition temperature is higher than 1000 °C. The crystal size and SiO2/Al2O3 ratio of as-synthesized NaY zeolite depend on low temperature crystallization time and the alkalinity.

Influence of AC-Voltage on the Crystallization of Amorphous Silicon Thin Film during Field Aided Lateral Crystallization Process

2005 ◽  
Vol 475-479 ◽  
pp. 1861-1864
Author(s):  
Sung Hwa Choi ◽  
Young Bae Kim ◽  
Yu Hang Wang ◽  
Duck Kyun Choi
Keyword(s):  
Amorphous Silicon ◽  
Crystallization Process ◽  
Silicon Film ◽  
Static Field ◽  
Silicon Thin Film ◽  
Experimental Frequency ◽  
Cu Catalyst ◽  
Ac Field ◽  
Lateral Crystallization ◽  
Temperature Crystallization

In field aided lateral crystallization process which is one of the low temperature crystallization processes for the amorphous silicon films, the effect of the alternating field (AC voltage) instead of the static field (DC voltage) was investigated. Following the deposition of 2 nm thick Cu catalyst outside of the 5 mm bar patterns in the PECVD amorphous silicon film, the specimen was heated at 500°C in N₂ambient for 5 hours with applying 5 V/cm AC-field along with 30 V/cm DC-field. As compared to the case of 35 V/cm DC-field only, the specimen from both the 30 V/cm DC and 5 V/cm AC resulted in 1.5 times faster crystallization velocity, regardless of the experimental frequency ranges of 100 Hz ~ 50 MHz. Presumably, the enhancement of the crystallization velocity under the combined field is associated with the increase in the flux of the crucial diffusion species, Cu atoms, which govern the overall crystallization velocity due to the agitation effect by the AC-field.

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