scholarly journals Microwave Mutagenesis of Brevibacillus Parabrevis for Enhanced Cellulase Production, and Investigation on Thermostability of this Cellulase

2016 ◽  
Author(s):  
Pinakin Khambhala ◽  
Purva Paliwal ◽  
Vijay Kothari
Keyword(s):  
Heat Treatment ◽  
Cellulase Activity ◽  
Microwave Treatment ◽  
Cellulase Production ◽  
Enzyme Preparations ◽  
Heat Treated ◽  
Major Loss ◽  
Thermal Stability Of ◽  
Brevibacillus Parabrevis ◽  
Reversible Nature

ABSTRACTMicrowave mutagenesis of Brevibacillus parabrevis for enhanced cellulase production was attempted. Though microwave treatment could alter the cellulase activity of the test bacterium, none of the mutants obtained were found to be genetically stable, indicating the reversible nature of microwave-induced mutation(s). Thermal stability of the B. parabrevis cellulase was also investigated. This enzyme was found to be capable of retaining its activity even after heat treatment (50-121°C, for 30-60 min). Fluorescence spectrum revealed a red shift in the emission maxima of the heat-treated enzyme preparations, indicating some structural change upon heating, but no major loss of activity was observed. This enzyme was found to be active over a broad temp range, with 90°C as the optimum temp, which is interesting as the producing organism is a mesophile.

scholarly journals Effects of aluminum sulfate soaking pretreatment on dimensional stability and thermostability of heat-treated wood

2020 ◽  
Author(s):  
Lijie Qu ◽  
Zhenyu Wang ◽  
Jing Qian ◽  
Zhengbin He ◽  
Songlin Yi
Keyword(s):  
Heat Treatment ◽  
Thermal Stability ◽  
Thermal Degradation ◽  
Structural Changes ◽  
Aluminum Sulfate ◽  
Treated Wood ◽  
Treatment Temperature ◽  
Chinese Fir ◽  
Heat Treated ◽  
Thermal Stability Of

Abstract Acidic aluminum sulfate hydrolysis solutions can be used to catalyze the thermal degradation of wood in a mild temperature environment, and thus reduce the temperature required for heat treatment process. To improve the dimensional and thermal stability of Chinese fir during heat treatment at 120 °C, 140 °C and 160 °C, this study investigated the effects of soaking pretreatment with 5%, 10% and 15% aluminum sulfate on the chemical and structural changes of the heat-treated Chinese fir. The results indicated that the samples treated at 15% aluminum sulfate concentration and 160 °C heat treatment achieved the best dimensional and thermal stability. Chemical analyses by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) indicated that the catalysis of aluminum sulfate resulted in degradation of hemicelluloses during the heat treatment, and an increase in the soaking concentration and heat treatment temperature also affected the thermal degradation of celluloses. The scanning electron microscope (SEM) and mass changes test results proved that the hydrolyzed aluminum flocs mainly adhered to the inner wall of the wood tracheid as spherical precipitates, and when the soaking concentration reached 10% and 15%, a uniform soaking effect could be achieved. The thermogravimetric (TG) analysis revealed the soaking pretreatment effectively improved the thermal stability of the heat-treated wood by physically wrapping and promoting the formation of a carbon layer on the wood surface during heat treatment. Thus, aluminum sulfate soaking pretreatment exerted a great effect on the dimensional and thermal stability of wood, allowing heat treatment to be performed at a lower temperature.

scholarly journals Effect of different heat treatment on alkylresorcinol contents of wheat bran

BioResources ◽  
2020 ◽  
Vol 15 (1) ◽  
pp. 1500-1509
Author(s):  
Shuanqi Tian ◽  
Renyong Zhao ◽  
Tianyuan Peng ◽  
Chenxi Liu ◽  
Yingqi Yang
Keyword(s):  
Heat Treatment ◽  
Wheat Bran ◽  
Loss Rate ◽  
Microwave Treatment ◽  
Heat Treatments ◽  
The Other ◽  
Wheat Cultivars ◽  
Wheat Varieties ◽  
Autoclave Treatment ◽  
Thermal Stability Of

The influence of different heat treatment levels on the contents of alkylresorcinol and homologues (ARs) was evaluated using wheat bran from two different wheat cultivars. The ARs in the wheat bran were destroyed by all heat treatments investigated in this study (oven treatment, microwave treatment, autoclave treatment, and extrusion treatment). The results showed that the loss rate of ARs by different heat treatment was oven treatment > autoclave treatment > extrusion treatment > microwave treatment, indicating that microwave treatment was more suitable for stabilizing wheat bran than the other three heat treatments. Both temperature and time of heat treatment had effects on the ARs of wheat bran. Higher temperatures and longer times of the treatment resulted in higher loss rates of ARs of wheat bran. The thermal stability of ARs homologues was different between wheat varieties, which may result from the variance of their structure and other components in wheat bran.

Thermal Stability of Cu and Cu2O Nanoparticles in a Polyimide Film

2008 ◽  
Vol 8 (9) ◽  
pp. 4822-4825 ◽  
Author(s):  
Jae-Youn Choi ◽  
Wenguo Dong ◽  
Dong Joo Choi ◽  
Chong S. Yoon ◽  
Young-Ho Kim
Keyword(s):  
Heat Treatment ◽  
Thermal Stability ◽  
Polyimide Film ◽  
Cu Nanoparticles ◽  
Transmission Electron ◽  
Heat Treated ◽  
Cu Film ◽  
Vis Spectroscopy ◽  
Cu2o Nanoparticles ◽  
Thermal Stability Of

Nanoparticles of Cu or Cu oxide dispersed in a polyimide (PI) film were fabricated by reaction of polyamic acid with a thin Cu film during imidization. In this paper, the thermal stability of the Cu or Cu oxide nanoparticles was investigated under various atmospheres. The PI/nanoparticle composites were heat-treated at 140 °C and 250 °C in air, N2, Ar, and 5% H2 atmospheres. Nanoparticles in the PI film were characterized by UV-VIS spectroscopy and transmission electron microscopy. The optical absorption peaks originating from Cu or Cu2O nanoparticles were changed by heat-treatment in different atmospheres. When Cu nanoparticles were oxidized by heat-treatment in air, the surface plasmon resonance (SPR) peak originating from the Cu nanoparticles disappeared. The quantum confined absorption peak of Cu2O was not affected by heat-treatment in N2 or Ar. Cu2O nanoparticles were reduced by heat-treatment at 250 °C in 5% H2 atmosphere and a new SPR peak appeared. Our results show that Cu nanoparticles are easily oxidized and highly dense Cu nanoparticles can be formed by reducing Cu2O nanoparticles.

Microstructure and Phase Composition of Iridium Coating on Molybdenum after Heat Treatment at 1400°C

2011 ◽  
Vol 189-193 ◽  
pp. 688-691 ◽  
Author(s):  
Wang Ping Wu ◽  
Zhao Feng Chen ◽  
Xin Lin
Keyword(s):  
Phase Transition ◽  
Heat Treatment ◽  
Thermal Stability ◽  
X Ray Diffraction ◽  
X Ray ◽  
Surface And Interface ◽  
Heat Treated ◽  
Glow Plasma ◽  
Ar Gas ◽  
Thermal Stability Of

Iridium (Ir) could be taken as high temperature protective coating for the refractory metals. Ir coating was deposited on the surface of molybdenum (Mo) substrate by double glow plasma. Thermal stability of the coating was investigated at 1400°C for 90 min, while Ar gas was inputted to hold the vacuum pressure. The microstructure of the surface and interface of the Ir coating were observed by SEM and TEM. The phase transition of the coating was determined by X-ray diffraction. Many micropores and microbubbles appeared in the surface of the as-heat treated coating. The interfacial reaction between the Mo substrate and Ir coating occurred during heat treatment, and Ir21.5Mo8.5 phase was formed at 1400°C. The experimental results indicated that the integrity of the Ir coating was not degraded after heat treatment.

Strength properties and dimensional stability of particleboards with different proportions of thermally treated recycled pine particles

Holzforschung ◽  
2016 ◽  
Vol 70 (5) ◽  
pp. 467-474 ◽  
Author(s):  
Paulo Ivan Andrade ◽  
Solange de Oliveira Araújo ◽  
Duarte Miranda Neiva ◽  
Benedito Rocha Vital ◽  
Angélica de Cássia Oliveira Carneiro ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Thermal Stability ◽  
Dimensional Stability ◽  
Lignin Content ◽  
Strength Properties ◽  
Raw Material ◽  
Heat Treated ◽  
Wood Particles ◽  
Partial Degradation ◽  
Thermal Stability Of

Abstract Wood-based panels made of waste and recycled raw material are lacking of dimensional stability. The aim of this study is to evaluate the potential beneficial effect of heat treatment (HT) on the properties of particleboards produced from waste of Pinus sp. used for packaging. The wood particles were heat treated at 180°C, 200°C and 220°C after grinding, and panels were produced with incorporation of 25%, 50%, 75% and 100% HT particles. The materials served as reference were particles without HT. Mass loss at 180°C and 200°C was small but increased significantly to 10.6% at 220°C. The HT caused a partial degradation of hemicelluloses, thereby the relative lignin content increased from 29.7% to 37.8% for the HT220°C samples. Thermogravimetry revealed higher thermal stability of the HT particles. The equilibrium moisture content decreased with HT, e.g. panels with HT220°C showed 30% lower compared to the reference. Swelling of the panels was lowered by 30% (panel with 75% HT material) compared to the reference. The results with HT pine were successful in terms of dimensional stability and lower hygroscopicity; however, the panels lost some strength properties.

scholarly journals Tailoring the Glass Composition to Increase the Thermal Stability without Impacting the Crystallization Behavior of Oxyfluorophosphate Glass

Ceramics ◽  
2021 ◽  
Vol 4 (2) ◽  
pp. 148-159
Author(s):  
Nirajan Ojha ◽  
Iuliia Dmitrieva ◽  
Wilfried Blanc ◽  
Laeticia Petit
Keyword(s):  
Heat Treatment ◽  
Thermal Stability ◽  
Glass Ceramic ◽  
Glass Composition ◽  
Glass Ceramics ◽  
Glass Network ◽  
Thermally Stable ◽  
Heat Treated ◽  
The Impact ◽  
Thermal Stability Of

Even though the (75 NaPO3-25 CaF2) (in mol%) glass can be heat-treated into transparent glass-ceramic with Er3+ doped CaF2 crystals precipitating in the volume of the glass during heat-treatment, this glass was found to be a poor glass former, limiting its use as upconverter under 975 nm pumping. In this study, the impact of the glass composition on the thermal, optical and structural properties of the glass was investigated in order to understand how the glass composition can be tailored for the development of thermally stable upconverter glass-based material. The addition of MgO, Fe2O3 and Al2O3 in the NaPO3-CaF2 glass system increases the thermal stability of glass due to the depolymerization of the glass network. However, the changes in the glass composition also impacted on the nucleation and growth process. Indeed, CaF2 and other crystals were found in the newly developed glasses after heat-treatment leading to glass-ceramics with lower intensity of upconversion than the (75 NaPO3-25 CaF2) glass-ceramic used as a reference. Glasses were also prepared with different concentrations of Er2O3 and ErF3. These glasses were found to be promising as not only are they thermally stable, but they also exhibit green and red emission with high intensity under 975 nm pumping due to Er3+ clustering.

The Spectral Properties and Thermal Stability of AlCr-AlCrON Solar Selective Absorber Coating

2013 ◽  
Vol 423-426 ◽  
pp. 419-425
Author(s):  
Ya Nan Li ◽  
Xiang Rong Liu ◽  
Yin Fang Cui ◽  
Jia Qi Liu ◽  
Guang Ming Xie ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Thermal Stability ◽  
Spectral Properties ◽  
Dc Magnetron Sputtering ◽  
Solar Absorptance ◽  
Thermal Emittance ◽  
Solar Absorber ◽  
Spectrally Selective ◽  
Heat Treated ◽  
Thermal Stability Of

Spectrally selective AlCr-AlCrON cermet solar absorber coating has been deposited on Cu substrate experimentally by reactive DC magnetron sputtering and heat-treated in air at 300°C for 2h. The spectral properties and thermal stability of the as-synthesized AlCr-AlCrON coatings were characterized. The solar absorptance and thermal emittance of the as-synthesized AlCr-AlCrON coating are 0.926 and 0.065, respectively. In addition, after heat treatment at 300 ° C for 500 h in air, the spectral properties of the as-synthesized AlCr-AlCrON coating is virtually unchanged. The results indicate that the as-synthesized AlCr-AlCrON coating has good spectral properties and thermal stability, which will be a good selective absorbing coating for mid-temperature solar vacuum collector tubes.

The Thermal Stability of Mo(Al,Si)2 Phase

2007 ◽  
Vol 280-283 ◽  
pp. 1475-1478 ◽  
Author(s):  
Xiao Li Zhang ◽  
Jian Feng Yang ◽  
Zhen Lin Lu ◽  
Zhi Hao Jin
Keyword(s):  
Heat Treatment ◽  
Thermal Stability ◽  
Aluminum Content ◽  
Formation Temperature ◽  
N2 Atmosphere ◽  
Heat Treated ◽  
Oxidation Properties ◽  
Al Addition ◽  
Thermal Stability Of

It has been reported that formation of Mo(Al,Si)2 phases by the addition of aluminum can improve the mechanical and oxidation properties of MoSi2, however, the constancy of the Mo(Al,Si)2 phase was not explored. In this study, MoSi2 preforms were added with Al whose contents were 1, 5, 10wt%, respectively, and these performs were sintered at 1150°C-1550°C, respectively. These MoSi2 specimens with the Al addition were heat-treated at 1350°C-1550°C in N2 atmosphere. Results showed that single Mo(Al,Si)2 phase existed only when the aluminum content was above 5 wt%. It was difficult to form single Mo(Al,Si)2 phase for the samples with 1wt% Al addition. For the samples with 5wt% Al, only the single Mo(Al,Si)2 phase was formed at 1350°C; and a large number of the tetragonal MoSi2 were re-appeared at 1450°C, 1550°C. For the samples with 10wt% Al addition, the single Mo(Al,Si)2 phase would always formed at individual sintering temperatures. The formation temperature of the single Mo(Al,Si)2 phase was decreased with increment of aluminum content. For the samples composed of the single Mo(Al,Si)2 phase, the Mo(Al,Si)2 phase disappeared gradually and was substituted for MoSi2 and a little of other phases, such as Mo3Al4Si2, by heat treatment at temperatures mentioned above for 40 min. This indicated that the Mo(Al,Si)2 phase was unstable at the temperatures above 1350°C.

Effect of a Complex Heat Treatment on the Structure of 300M Steel

1981 ◽  
Vol 39 ◽  
pp. 312-313
Author(s):  
R. Padmanabhan ◽  
W. E. Wood
Keyword(s):  
Heat Treatment ◽  
Metal Carbides ◽  
Austenite Grain Size ◽  
300M Steel ◽  
Heat Treated ◽  
Strain Fracture ◽  
Prior Austenite Grain Size ◽  
Short Time ◽  
Final Tempering ◽  
Similar Yield

Intermediate high temperature tempering prior to subsequent reaustenitization has been shown to double the plane strain fracture toughness as compared to conventionally heat treated UHSLA steels, at similar yield strength levels. The precipitation (during tempering) of metal carbides and their subsequent partial redissolution and refinement (during reaustenitization), in addition to the reduction in the prior austenite grain size during the cycling operation have all been suggested to contribute to the observed improvement in the mechanical properties. In this investigation, 300M steel was initially austenitized at 1143°K and then subjected to intermediate tempering at 923°K for 1 hr. before reaustenitizing at 1123°K for a short time and final tempering at 583°K. The changes in the microstructure responsible for the improvement in the properties have been studied and compared with conventionally heat treated steel. Fig. 1 shows interlath films of retained austenite produced during conventionally heat treatment.

“In vitro” and in Animal Model Studies on a Double Virus- Inactivated Factor VIII Concentrate

1995 ◽  
Vol 74 (03) ◽  
pp. 868-873 ◽  
Author(s):  
Silvana Arrighi ◽  
Roberta Rossi ◽  
Maria Giuseppina Borri ◽  
Vladimir Lesnikov ◽  
Marina Lesnikov ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Animal Model ◽  
Factor Viii ◽  
Hepatitis A ◽  
Hepatitis A Virus ◽  
Virus Inactivation ◽  
Enveloped Viruses ◽  
Model Studies ◽  
Heat Treated

SummaryTo improve the safety of plasma derived factor VIII (FVIII) concentrate, we introduced a final super heat treatment (100° C for 30 min) as additional virus inactivation step applied to a lyophilized, highly purified FVIII concentrate (100 IU/mg of proteins) already virus inactivated using the solvent/detergent (SID) method during the manufacturing process.The efficiency of the super heat treatment was demonstrated in inactivating two non-lipid enveloped viruses (Hepatitis A virus and Poliovirus 1). The loss of FVIII procoagulant activity during the super heat treatment was of about 15%, estimated both by clotting and chromogenic assays. No substantial changes were observed in physical, biochemical and immunological characteristics of the heat treated FVIII concentrate in comparison with those of the FVIII before heat treatment.

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