scholarly journals Isomerization of Methyl-Eugenol catalyzed by [RuCl2(PPh3)3] In CO2 Atmosphere At Different Temperatures

2021 ◽  
Author(s):  
Alexandre Diógenes Pereira ◽  
Aline Aparecida Carvalho França ◽  
Kerlane Alves Fernandes ◽  
Ana Karina Borges Costa ◽  
Sâmia Dantas Braga ◽  
...  
Keyword(s):  
Methyl Eugenol ◽  
Controlled Atmosphere ◽  
Free Atmosphere ◽  
Alternative System ◽  
Different Temperatures ◽  
Substrate Ratio ◽  
Co2 Atmosphere

Dichlorotristriphenylphosphinerruthenium(II) complex was used as initiator in isomerization reactions of methyl-eugenol to iso-methyl-eugenol, under controlled atmosphere. The reactions were performed for 24 h in CO2 atmosphere as an oxygen-free atmosphere alternative system, at temperatures of 25, 50 and 75 °C, with a catalyst/substrate ratio of 1: 100 mol. At the end of each experiment, an aliquot of the reaction mixture was removed and analyzed by GC-MS. Approximately 85 % conversion and 75 % selectivity were observed when the experiments were carried out at 50 °C.

scholarly journals An Experimental Study of the Decomposition and Carbonation of Magnesium Carbonate for Medium Temperature Thermochemical Energy Storage

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1316
Author(s):  
Daniel Mahon ◽  
Gianfranco Claudio ◽  
Philip Eames
Keyword(s):  
Thermal Analysis ◽  
Thermal Decomposition ◽  
Energy Storage ◽  
Magnesium Carbonate ◽  
Experimental Results ◽  
Future Research ◽  
Medium Temperature ◽  
Different Temperatures ◽  
Decomposition Enthalpy ◽  
Co2 Atmosphere

To improve the energy efficiency of an industrial process thermochemical energy storage (TCES) can be used to store excess or typically wasted thermal energy for utilisation later. Magnesium carbonate (MgCO3) has a turning temperature of 396 °C, a theoretical potential to store 1387 J/g and is low cost (~GBP 400/1000 kg). Research studies that assess MgCO3 for use as a medium temperature TCES material are lacking, and, given its theoretical potential, research to address this is required. Decomposition (charging) tests and carbonation (discharging) tests at a range of different temperatures and pressures, with selected different gases used during the decomposition tests, were conducted to gain a better understanding of the real potential of MgCO3 for medium temperature TCES. The thermal decomposition (charging) of MgCO3 has been investigated using thermal analysis techniques including simultaneous thermogravimetric analysis and differential scanning calorimetry (TGA/DSC), TGA with attached residual gas analyser (RGA) and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) (up to 650 °C). TGA, DSC and RGA data have been used to quantify the thermal decomposition enthalpy from each MgCO3.xH2O thermal decomposition step and separate the enthalpy from CO2 decomposition and H2O decomposition. Thermal analysis experiments were conducted at different temperatures and pressures (up to 40 bar) in a CO2 atmosphere to investigate the carbonation (discharging) and reversibility of the decarbonation–carbonation reactions for MgCO3. Experimental results have shown that MgCO3.xH2O has a three-step thermal decomposition, with a total decomposition enthalpy of ~1050 J/g under a nitrogen atmosphere. After normalisation the decomposition enthalpy due to CO2 loss equates to 1030–1054 J/g. A CO2 atmosphere is shown to change the thermal decomposition (charging) of MgCO3.xH2O, requiring a higher final temperature of ~630 °C to complete the decarbonation. The charging input power of MgCO3.xH2O was shown to vary from 4 to 8136 W/kg with different isothermal temperatures. The carbonation (discharging) of MgO was found to be problematic at pressures up to 40 bar in a pure CO2 atmosphere. The experimental results presented show MgCO3 has some characteristics that make it a candidate for thermochemical energy storage (high energy storage potential) and other characteristics that are problematic for its use (slow discharge) under the experimental test conditions. This study provides a comprehensive foundation for future research assessing the feasibility of using MgCO3 as a medium temperature TCES material. Future research to determine conditions that improve the carbonation (discharging) process of MgO is required.

scholarly journals Elevated CO2 Atmosphere for Storage of Mature-green and Tree-ripe `Tommy Atkins' Mangoes

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 804F-805
Author(s):  
R.J. Bender ◽  
J.K. Brecht
Keyword(s):  
Ethylene Production ◽  
Skin Color ◽  
Ethylene Biosynthesis ◽  
Controlled Atmosphere ◽  
Tropical Fruits ◽  
Long Distance ◽  
Color Development ◽  
Storage Atmosphere ◽  
Green Stage ◽  
Co2 Atmosphere

Mangoes for long-distance markets are harvested at the mature-green stage and shipped in refrigerated containers. Shipment under controlled atmosphere is still tentative, and the CO2 concentrations used are relatively low (maximum 10%), although mangoes have been reported as being less-sensitive to elevated CO2 than other tropical fruits. In the present study, CO2 concentrations of 10%, 15%, 25%, 35%, and 45% combined with 5% O2 were used to store mangoes. Mature-green `Tommy Atkins' were stored for 21 days at 12C, followed by air storage at 20C for 5 days. Tree-ripe mangoes were stored at 8 or 12C under the same conditions. Ethanol production rates increased along with increasing CO2 concentrations. However, only 35% and 45% CO2 atmospheres inflicted damage. Color development was severely inhibited under those treatments. Lower CO2 treatments, up to 25% in the storage atmosphere, inhibited skin color development and ethylene biosynthesis but, after 5 days in air at 20C, skin color and ethylene production reached control levels. Fruit flesh firmness did not differ among treatments at 12C. Tree ripe mangoes stored in CA at 8C were only significantly firmer than control fruit at transfer from CA to air.

The effects of soybean storage under controlled atmosphere at different temperatures on lipid oxidation and volatile compounds profile

2021 ◽  
pp. 110483
Author(s):  
Vagner Ludwig ◽  
Magno Roberto Pasquetti Berghetti ◽  
Stephanie Reis Ribeiro ◽  
Fabiane Portella Rossato ◽  
Lucas Mallmann Wendt ◽  
...  
Keyword(s):  
Lipid Oxidation ◽  
Volatile Compounds ◽  
Controlled Atmosphere ◽  
Different Temperatures

Effect of controlled atmosphere, vacuum packaging and different temperatures on the growth of spoilage fungi in shelled pecan nuts during storage

Food Control ◽  
2021 ◽  
pp. 108173
Author(s):  
Stephanie Reis Ribeiro ◽  
Marcelo Valle Garcia ◽  
Marina Venturini Copetti ◽  
Auri Brackmann ◽  
Vanderlei Both ◽  
...  
Keyword(s):  
Vacuum Packaging ◽  
Controlled Atmosphere ◽  
Different Temperatures ◽  
Spoilage Fungi

scholarly journals Post-Harvest Conservation of Baby Corn Under Controlled Atmosphere and Refrigeration

2019 ◽  
Vol 11 (15) ◽  
pp. 78
Author(s):  
Polyana Danyelle S. Silva ◽  
Caik M. Batista ◽  
Marcela C. Soares ◽  
Wagner F. Mota ◽  
Samy Pimenta
Keyword(s):  
Storage Time ◽  
Storage Condition ◽  
Physicochemical Characteristics ◽  
Quality Characteristics ◽  
Controlled Atmosphere ◽  
Production Chain ◽  
Post Harvest ◽  
Different Temperatures ◽  
Temperature Controlled ◽  
Storage Temperatures

The baby corn has been gaining ground in the market and arousing interest of producers. However, there is a barrier in its production chain due to the lack of scientific knowledge in the harvest and post-harvest strategies. Therefore, the objective of this study was to evaluate the changes in the physicochemical characteristics of the baby corn stored at different temperatures and under controlled atmosphere. The studies were performed at UNIMONTES with the ‘AG 1051’ baby corn spikletes. Two tests were performed, one considering the spikelets in the straw and the other with the husked spikelets. The tests were carried out under CRD, in a 2 × 2 × 6 factorial scheme, that is two storage temperatures (16 and 25 °C), two controlled atmosphere conditions (with and without PVC plastic wrap) and six evaluation periods (0, 3, 6, 9, 12 and 15 days after harvest) with four replications. The quality characteristics of the spikelets were analyzed in the post-harvest. the post-harvest quality preservation of baby corn in the straw and the husked ones was affected by temperature, controlled atmosphere and evaluation period. The best storage condition to maintain the main quality characteristics of the spikelets at post-harvest was observed at the temperature of 16 ºC with controlled atmosphere use. For the spikelets preserved with the presence of straw, the maximum storage time for maintenance of post-harvest characteristics was four days, and for spikelets stored without straw, the maximum storage time was two days and 12 hours, both at refrigerated temperature (16 °C) and under controlled atmosphere.

scholarly journals Effect of temperature and enzyme/substrate ratio on the hydrolysis of pea protein isolates by trypsin

2011 ◽  
Vol 20 (No. 1) ◽  
pp. 1-6 ◽  
Author(s):  
m. Karamać ◽  
r. Amarowicz ◽  
h. Kostyra
Keyword(s):  
Effect Of Temperature ◽  
Degree Of Hydrolysis ◽  
Protein Isolates ◽  
Pea Protein ◽  
Enzyme Substrate ◽  
Different Temperatures ◽  
Ph Stat ◽  
Substrate Ratio ◽  
Stat Method ◽  
The Relationship

Two pea protein isolates, Pisane and Propulse, were hydrolysed by trypsin. The degree of hydrolysis (DH) was computed using a pH-stat method. Enzymatic treatment of the pea protein isolates was conducted at four different temperatures, namely 35, 40, 45 and 50°C. The relationship between DH and E/S ratio was studied at 50°C and at four different E/S ratios; these were 5, 15, 25, 35 mAU/g (AU – Anson unit). For Pisane the highest value of the final DH (10.4%) was obtained at 45°C, whereas for Propulse the optimal temperature was 50°C and a DH value of 13.2% was attained. In the case of Pisane, the highest DH (11.5%) was recorded if the enzyme/substrate ratio was 35 mAU/g whereas for Propulse, the highest DH (13.2%) was observed at an E/S ratio of 15 mAU / g.  

scholarly journals Effect of deformation on densification and corrosion behavior of Al-ZrB2 composite

10.30544/264 ◽  
2017 ◽  
Vol 23 (1) ◽  
pp. 47-63 ◽  
Author(s):  
Sai Mahesh Yadav Kaku ◽  
Asit Kumar Khanra ◽  
M J Davidson
Keyword(s):  
Metal Matrix ◽  
Effect Of Temperature ◽  
Controlled Atmosphere ◽  
Matrix Composites ◽  
Dynamic Polarization ◽  
Mechanical Working ◽  
Argon Gas ◽  
Aspect Ratios ◽  
Different Temperatures ◽  
Polarization Studies

In the present investigation, aluminium based metal matrix composites (MMCs) were produced through powder metallurgical route. Different composites were processed by adding different amount of ZrB2 (0, 2, 4 and 6 wt. %) at three aspect ratios of 0.35, 0.5, and 0.65, respectively. The powder mixture was compacted and pressureless sintered at 550 °C for 1 h in controlled atmosphere (argon gas). The relative density of the sintered preforms was found to be 90%, approximately. Sintered preforms are used as workpiece materials for deformation study at different temperatures in order to find the effect of temperature on the densification behaviour. Potentio-dynamic polarization studies were performed on the deformed preforms to find the effect of mechanical working. The corrosion rate was found to decrease with increase in deformation.

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