Analysis of the Heat Transfer of Ginkgo Biloba Seeds during Radio-Frequency Heating

AbstractFresh ginkgo biloba (GB) seeds are seasonal and susceptible to microbial spoilage, especially the growth of mold owing to GB seeds’ high-water content, which greatly limits their shelf life. As an efficient and special heating method, radio-frequency (RF) heating can be used to dehydrate ginkgo to preserve its nutritional value and reduce postharvest losses. However, the non-uniformity of RF heating restricts the development in industrialized application. In this study, the RF drying of GB seeds was performed to investigate the effect of RF heating on temperature. The distribution law of the entire temperature field was also observed. Using numerical simulation method, the coupling model of electromagnetic and heat transfer was established. The model was validated by the 6-min heating profile of GB seeds in a 12 kw and 27.12 MHz RF system. The model was also qualitatively validated by comparing the simulated temperature profiles on the three planes in the GB seeds with the corresponding thermal images. Quantitative validation was performed by comparing the simulated temperature of GB seeds on the three planes with experimental temperature acquired at places using thermocouples. Furthermore, the model can be effectively used to identify the distribution of electric fields in different positions and to achieve satisfactory heating uniformity.

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Effect of High Intensity Pulsed Electric Fields on Antioxidant Substances of Postharvest Ginger

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.140.319 ◽

2011 ◽

Vol 140 ◽

pp. 319-323 ◽

Cited By ~ 1

Author(s):

Yu Zhu Han ◽

Shu Yao Song

Keyword(s):

Electric Fields ◽

High Intensity ◽

Economic Value ◽

Membrane Integrity ◽

High Water ◽

High Water Content ◽

Total Flavonoids ◽

Cell Membrane Integrity ◽

Long Time

The antioxidant substances of ginger are extremely easy to degrade in the process of store and its quality and economic value are also degraded. The effects of high intensity pulsed electric field (HIPEF) treatment on the SOD, POD, PPO, Vc, total flavonoid, polysaccharide were studied. The results show that 0.8kV/cm for 5min treatment of HIPEF can maintain the cell membrane integrity, restrain the relative electric conductivity, maintain the high water content and the content of antioxidant substances, enhance the SOD and POD activity, restrain the PPO activity and the degradation of Vc , total flavonoids and polysaccharide, and inhibit the enzymatic browning of ginger to some extent, so that the quality of postharvest ginger during storage are kept well and more long time.

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Efek Zeolit untuk Produksi Tar dan Char pada Pirolisis Rotary Kiln

Jurnal Rekayasa Mesin ◽

10.21776/ub.jrm.2021.012.01.6 ◽

2021 ◽

Vol 12 (1) ◽

pp. 51

Author(s):

Widya Wijayanti

Keyword(s):

Heat Transfer ◽

Rotary Kiln ◽

Fixed Bed ◽

Mesh Size ◽

High Water ◽

Fixed Bed Reactor ◽

High Water Content ◽

Pyrolysis Process ◽

Pyrolysis Products ◽

Biomass Decomposition

<p class="00textwithtab">This study aims to investigate the effect of zeolite as a catalyst to enlarge biomass decomposition in the pyrolysis process. It absorbs a high water content in the biomass, besides it makes the easier breaking of biomass molecules to maximize the biomass decomposition into the expected pyrolysis products; tar and char. In addition, to decompose the biomass molecules, the zeolite also stimulates the rate of heat transfer due to its ability to hold and release the heat. If the previous research pyrolysis was conducted in a fixed bed reactor, in this study, it will be carried out rotary kiln as a pyrolysis furnace. If the fixed bed reactor the heat transfer was dominated by conduction, the heat transfer in the rotary kiln is more controlled by the convection and radiation transfer due to stirring and turning of biomass by the kiln. In the study, the biomass used was mahogany with an initial weight of 150 grams. The rotary kiln rotated at 10 rpm and the heating rate during the pyrolysis process was around 0.1483°C/s. The pyrolysis temperatures used were varied as 250°C, 350°C, 450°C. Meanwhile, the percentage of zeolites used from 0% to 60% with a mesh size of 80. The results showed that zeolites were able to increase tar production and maximize the reduction of char as an effect of the Bronsted-Lowry and Lewis reaction in the process of catalytic cracking. The maximum production of tar and char production was also supported by the process of convection and radiation from the rotary kiln wall increasing the rate of heat transfer to decompose the biomass.</p><p class="02abstracttext"> </p>

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Heat Transfer Limitations in Supercritical Water Gasification

Energies ◽

10.3390/en15010177 ◽

2021 ◽

Vol 15 (1) ◽

pp. 177

Author(s):

Francisco Javier Gutiérrez Gutiérrez Ortiz ◽

Francisco López-Guirao ◽

Francisco José Jiménez-Espadafor ◽

José Manuel Benjumea

Keyword(s):

Heat Transfer ◽

Supercritical Water ◽

Experimental Studies ◽

High Water ◽

Conventional Heating ◽

Slow Heating ◽

High Water Content ◽

Fluid Temperature ◽

Factors Affecting ◽

Supercritical Water Gasification

Supercritical water gasification (SCWG) is a promising technology for the valorization of wet biomass with a high-water content, which has attracted increasing interest. Many experimental studies have been carried out using conventional heating equipment at lab scale, where researchers try to obtain insight into the process. However, heat transfer from the energy source to the fluid stream entering the reactor may be ineffective, so slow heating occurs that produces a series of undesirable reactions, especially char formation and tar formation. This paper reviews the limitations due to different factors affecting heat transfer, such as low Reynolds numbers or laminar flow regimes, unknown real fluid temperature as this is usually measured on the tubing surface, the strong change in physical properties of water from subcritical to supercritical that boosts a deterioration in heat transfer, and the insufficient mixing, among others. In addition, some troubleshooting and new perspectives in the design of efficient and effective devices are described and proposed to enhance heat transfer, which is an essential aspect in the experimental studies of SCWG to move it forward to a larger scale.

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Heat Transfer Characteristic in High-water Content Agar Phantoms for Local Hyperthermia

The Proceedings of Conference of Chugoku-Shikoku Branch ◽

10.1299/jsmecs.2002.71 ◽

2002 ◽

Vol 2002 (0) ◽

pp. 71-72

Author(s):

Shinfuku NOMURA ◽

Hiroshi YAMASAKI ◽

Tunehiro MAEHARA ◽

Kensuke KONISHI ◽

Yuji WATANABE

Keyword(s):

Heat Transfer ◽

Water Content ◽

Heat Transfer Characteristic ◽

Transfer Characteristic ◽

High Water ◽

High Water Content ◽

Local Hyperthermia

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HEAT TRANSFER AUGMENTATION AROUND A DOWNWARD-FACING FLAT PLATE BY NON-UNIFORM ELECTRIC FIELDS

Proceeding of International Heat Transfer Conference 6 ◽

10.1615/ihtc6.2880 ◽

1978 ◽

Cited By ~ 4

Author(s):

A. Yabe ◽

Yasuo Mori ◽

Kunio Hijikata

Keyword(s):

Heat Transfer ◽

Flat Plate ◽

Electric Fields ◽

Heat Transfer Augmentation

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Features of spring feeding of sterlet of the middle course of the Northern Dvina river

Rybovodstvo i rybnoe hozjajstvo (Fish Breeding and Fisheries) ◽

10.33920/sel-09-2007-01 ◽

2020 ◽

pp. 8-17

Author(s):

A. Bykov ◽

D. Palatov ◽

I. Studenov ◽

D. Chupov

Keyword(s):

Benthic Communities ◽

High Water ◽

Food Composition ◽

Fish Growth ◽

High Water Content ◽

Feeding Intensity ◽

Biting Midges ◽

Size Groups ◽

Main Components ◽

A Minor

The article provides information about the features of spring feeding of sterlet in the spawning grounds of the middle course of the Northern Dvina river in may 2019. The main and secondary groups of forage objects in the diet of this species of sturgeon are characterized. The article considers the variability of the sterlet food composition with an increase in the size of fish from 30 to 60 cm. In the process of fish growth in the diet of the Severodvinsk sterlet, the main components in terms of occurrence and mass in all size groups are the larvae of Brooks and chironomids. A minor occurrence was the larvae of midges, biting midges, stoneflies, mayflies and small clams. To random and seasonal food are the larvae of water bugs, butterflies, flies, beetles and eggs of other fish. The feeding intensity of the smaller sterlet (30–40 cm) was significantly higher than that of the fish in the size groups 40–50 and 50–60 cm. Fundamental changes in the diet of the Severodvinsk sterlet for the main food objects for more than sixty years of observations have not been established. During periods of high water content of the Northern Dvina due to seasonal changes in the structure of benthic communities, the value of Brooks in the diet of sterlet increases and the proportion of chironomids decreases.

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Hydrogels as Antibacterial Biomaterials

Current Pharmaceutical Design ◽

10.2174/1381612824666180213122953 ◽

2018 ◽

Vol 24 (8) ◽

pp. 843-854 ◽

Cited By ~ 6

Author(s):

Weiguo Xu ◽

Shujun Dong ◽

Yuping Han ◽

Shuqiang Li ◽

Yang Liu

Keyword(s):

Mechanical Properties ◽

Drug Delivery ◽

Tissue Engineering ◽

Water Content ◽

Oxygen Permeability ◽

Structural Diversity ◽

High Water ◽

Clinical Applications ◽

High Water Content ◽

Biomedical Field

Hydrogels, as a class of materials for tissue engineering and drug delivery, have high water content and solid-like mechanical properties. Currently, hydrogels with an antibacterial function are a research hotspot in biomedical field. Many advanced antibacterial hydrogels have been developed, each possessing unique qualities, namely high water swellability, high oxygen permeability, improved biocompatibility, ease of loading and releasing drugs and structural diversity. In this article, an overview is provided on the preparation and applications of various antibacterial hydrogels. Furthermore, the prospects in biomedical researches and clinical applications are predicted.

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