Effect of Vacuum Impregnation on Combined Air-Microwave Drying of Apple

Author(s):  
Pedro Fito ◽  
M. E. Martín ◽  
N. Martínez-Navarrete ◽  
A. Chiralt ◽  
J. M. Catalá ◽  
...  
Author(s):  
P Fito ◽  
M Mart√≠n ◽  
N Mart√≠nez-Navarrete ◽  
A Chiralt ◽  
J Catal√° ◽  
...  

Author(s):  
Eduardo A. Kamenetzky ◽  
David A. Ley

The microstructure of polyacrylonitrile (PAN) beads for affinity chromatography bioseparations was studied by TEM of stained ultramicrotomed thin-sections. Microstructural aspects such as overall pore size distribution, the distribution of pores within the beads, and surface coverage of functionalized beads affect performance properties. Stereological methods are used to quantify the internal structure of these chromatographic supports. Details of the process for making the PAN beads are given elsewhere. TEM specimens were obtained by vacuum impregnation with a low-viscosity epoxy and sectioning with a diamond knife. The beads can be observed unstained. However, different surface functionalities can be made evident by selective staining. Amide surface coverage was studied by staining in vapor of a 0.5.% RuO4 aqueous solution for 1 h. RuO4 does not stain PAN but stains, amongst many others, polymers containing an amide moiety.


Author(s):  
Sunanda ◽  
◽  
Satish Kumar ◽  
H. G. Ramya ◽  
M. S. Alam ◽  
...  

Author(s):  
А. Zykov ◽  
S. Orlova ◽  
L. Ovsiannykova

The methods of energy efficiency increasing of pre- and post-harvest thermal processing of grain are considered. The effective ways to deliver energy to the grain using heat pipes and microwave field are given. The effect of combined action of microwave and low-frequency radiation on the grain germination is shown. Currently, the intensification of technological processes under the influence of microwave radiation is used in many industrial processes. Microwave equipment is becoming a necessary technological component of large profitable industries. The process of drying is no exception. In recent years, new versions of dryers have been proposed that use combined methods of energy supply, including microwave energy. Microwave dryers for foodstuffs, grains and oilseeds, including those for seed stock, have been created and are beginning to be used, along with drying and disinfection, disinfection of drying products from harmful bacteria, fungi, and mildew. For the implementation of microwave drying of particular importance is the choice of regime parameters of drying, given the fact that the grain is a biologically active object. Microwave drying allows you to provide a powerful flow of energy to the object of drying and to obtain a significant intensification of moisture evaporation. But at the same time there is also an intense heating of the product, which can degrade its quality. The possibility of supplying energy throughout the cross section of the product allows for the evaporation of moisture from the inner layers of the product, which is especially important at the end of drying, when the zone of evaporation of moisture is significantly deeper. Therefore, the highest drying efficiency can be obtained in combined processes that take advantage of various drying methods, such as convective, as well as the use of microwave and low-frequency magnetic fields. The paper presents effective ways to supply energy to the grain using heat pipes and a microwave field. The effect of the combined action of microwave and low-frequency radiation on grain similarity is shown. Ways to improve the energy efficiency of the processes of preseeding and post-harvest heat treatment of grain are considered.


2008 ◽  
Vol 73 (8-9) ◽  
pp. 945-955 ◽  
Author(s):  
Luděk Kaluža ◽  
Miroslav Zdražil

The transition metals V, Cr, Mn, Fe, Co, Ni, Mo, Ru, Rh, Pd, W, Re, Os, Ir and Pt were deposited from aqueous solutions of their salts onto conventional γ-Al2O3 and unconventional TiO2 and ZrO2 supports by vacuum impregnation and characterized in their sulfided form by a model reaction of benzothiophene hydrodesulfurization. It was found that the TiO2 and ZrO2 supports influenced predominantly positively the resulting activity of relatively low-active metals (V, Cr, Mn, Fe, Co, Ni, Mo, Ru, W and Os), whereas the highly active metals (Rh, Pd, Ir, Pt and Re) were influenced slightly negatively or not at all by those supports compared with the γ-Al2O3-supported system. A significant effect of the supports on the hydrodesulfurization-activity ranking of the transition-metal sulfides studied was ascertained.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Vali Rasooli Sharabiani ◽  
Mohammad Kaveh ◽  
Roozbeh Abdi ◽  
Mariusz Szymanek ◽  
Wojciech Tanaś

AbstractTwo different drying methods were applied for dehydration of apple, i.e., convective drying (CD) and microwave drying (MD). The process of convective drying through divergent temperatures; 50, 60 and 70 °C at 1.0 m/s air velocity and three different levels of microwave power (90, 180, and 360 W) were studied. In the analysis of the performance of our approach on moisture ratio (MR) of apple slices, artificial neural networks (ANNs) was used to provide with a background for further discussion and evaluation. In order to evaluate the models mentioned in the literature, the Midilli et al. model was proper for dehydrating of apple slices in both MD and CD. The MD drying technology enhanced the drying rate when compared with CD drying significantly. Effective diffusivity (Deff) of moisture in CD drying (1.95 × 10−7–4.09 × 10−7 m2/s) was found to be lower than that observed in MD (2.94 × 10−7–8.21 × 10−7 m2/s). The activation energy (Ea) values of CD drying and MD drying were 122.28–125 kJ/mol and 14.01–15.03 W/g respectively. The MD had the lowest specific energy consumption (SEC) as compared to CD drying methods. According to ANN results, the best R2 values for prediction of MR in CD and MD were 0.9993 and 0.9991, respectively.


Author(s):  
Hewen Zheng ◽  
Qiannan Li ◽  
Yeqing Ling ◽  
Mamdouh Omran ◽  
Lei Gao ◽  
...  

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