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1.
Food Chem ; 463(Pt 1): 141100, 2024 Sep 02.
Artículo en Inglés | MEDLINE | ID: mdl-39244993

RESUMEN

Low voltage electrostatic field (LVEF), a novel non-thermal processing technology, shows promise for food preservation. However, the absence of clear definition and quantification of the core concept "low voltage" obstructs the effective application of LVEF. This study assessed the efficiency of various LVEF intensities (100, 200, 300 V) on cherry tomato preservation, revealing significant differences in preservation efficiency. Compared to the control, samples treated with different intensities showed varied reductions in weight loss (6.26-25.45 %), firmness changes (5.17-28.91 %), and decay incidence (47.91-70.89 %). Quantitative analysis elucidated that the differential preservation efficiency may arise from a dose-response relationship between electric field strength and hydrogen peroxide (H2O2) content, identifying an optimal H2O2 content range of 21.18-27.01 mmol kg-1 for the effective preservation of cherry tomatoes under LVEF. These findings highlight the importance of precise LVEF intensity control for effective food preservation and offer insights for developing optimal LVEF treatment intensities for diverse produce.

2.
Heliyon ; 10(16): e35787, 2024 Aug 30.
Artículo en Inglés | MEDLINE | ID: mdl-39224326

RESUMEN

This research investigated the effectiveness of radio frequency (RF) heating as a treatment for lead-contaminated soil, assessing its impact through dielectric constant measurements. Using water-soluble lead (II) acetate trihydrate, the study analyzed the impact of RF heating on soil dielectric properties under various soil moisture conditions (high, medium, and low) and electric field strengths (112.5, 150, 225, and 450 kV/m). The results indicated that soil temperature increased with lead concentration, highlighting significant changes in soil thermodynamics. Under high-humidity conditions, temperature increases were more pronounced, suggesting that higher lead concentrations elevate soil temperatures. Moreover, RF heating consistently reduced the dielectric constant as lead concentration increased, which was especially evident at higher electric field strengths. The study found that the soil resistivity approached that of uncontaminated soil, particularly at 450 kV/m electric field strength, with the highest removal rate of 46.154%. This investigation provides valuable insights into the application of RF heating for soil quality improvement in lead-contaminated environments, demonstrating how dielectric properties can reflect those of uncontaminated soil.

3.
Int J Numer Method Biomed Eng ; 40(10): e3859, 2024 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-39154656

RESUMEN

Tumor treating fields (TTFields) is a novel therapeutic approach for the treatment of glioblastoma. The electric field intensity is a critical factor in the therapeutic efficacy of TTFields, as stronger electric field can more effectively impede the proliferation and survival of tumor cells. In this study, we aimed to improve the therapeutic effectiveness of TTFields by optimizing the position of electrode arrays, resulting in an increased electric field intensity at the tumor. Three representative head models of real glioblastoma patients were used as the research subjects in this study. The improved subtraction-average-based optimization (ISABO) algorithm based on circle chaos mapping, opposition-based learning and golden sine strategy, was employed to optimize the positions of the four sets of electrode arrays on the scalp. The electrode positions are dynamically adjusted through iterative search to maximize the electric field intensity at the tumor. The experimental results indicate that, in comparison to the conventional layout, the positions of the electrode arrays obtained by the ISABO algorithm can achieve average electric field intensity of 1.7887, 2.0058, and 1.3497 V/cm at the tumor of three glioblastoma patients, which are 23.6%, 29.4%, and 8.5% higher than the conventional layout, respectively. This study demonstrates that optimizing the location of the TTFields electrode array using the ISABO algorithm can effectively enhance the electric field intensity and treatment coverage in the tumor area, offering a more effective approach for personalized TTFields treatment.


Asunto(s)
Algoritmos , Electrodos , Glioblastoma , Glioblastoma/terapia , Humanos , Terapia por Estimulación Eléctrica/instrumentación , Terapia por Estimulación Eléctrica/métodos , Neoplasias Encefálicas/terapia , Medicina de Precisión/métodos
4.
Sci Total Environ ; 920: 170992, 2024 Apr 10.
Artículo en Inglés | MEDLINE | ID: mdl-38365016

RESUMEN

Microbial electrolysis cells (MECs) are increasingly recognized as a promising technology for converting CO2 to CH4, offering the dual benefits of energy recovery from organic wastewater and CO2 emission reduction. A critical aspect of this technology is the enhancement of the electron-accepting capacity of the methanogenic biocathode to improve CH4 production efficiency. This study demonstrates that adjusting the cathode resistivity is an effective way to control the electric field intensity, thereby enhancing the electron accepting capacity and CH4 production. By maintaining the electric field intensity within approximately 8.50-10.83 mV·cm-1, the CH4 yield was observed to increase by up to two-fold. The improvement in CH4 production under optimized electric field conditions was attributed to the enhancement of the direct accepting capacity of the biocathode. This enhancement was primarily due to an increase in the relative abundance of Methanosaeta by approximately 10 % and an up to 83.78 % rise in the electron-accepting capacity of the extracellular polymeric substance. These insights offer a new perspective on the operation of methanogenic biocathodes and propose a novel biocathode construction methodology based on these findings, thus contributing to the enhancement of MEC efficiency.


Asunto(s)
Fuentes de Energía Bioeléctrica , Carbono , Dióxido de Carbono , Matriz Extracelular de Sustancias Poliméricas , Electrólisis , Electrodos , Metano
5.
Materials (Basel) ; 16(24)2023 Dec 05.
Artículo en Inglés | MEDLINE | ID: mdl-38138648

RESUMEN

With the increasing power density of electronic devices, solder joints are prone to electromigration under high currents, which results in a significant threat to reliability. In this study, the molecular dynamics method is used to study the diffusion mechanism of the Cu3Sn/Cu interface under the action of electrothermal coupling. The results show that the diffusion activation energy decreases with an increase in electric field intensity, accelerating the diffusion of the Cu3Sn/Cu interface. Furthermore, it is noted that the abrupt change in the vacancy-time curve lags behind that of the mean square displacement curve, which depicts that the responses of the vacancies are driven by the electric field. The vacancy-responsive diffusion mechanism of the Cu3Sn/Cu interface is proposed. The atoms around the interface in the electric field get rid of the shackles of the neighboring atoms easily. The vacancy concentration increases as the atoms leave the equilibrium position, which accelerates the movement of vacancies and enhances the diffusion of the Cu3Sn/Cu interface.

6.
Cancer Cell Int ; 23(1): 110, 2023 Jun 07.
Artículo en Inglés | MEDLINE | ID: mdl-37287008

RESUMEN

PURPOSE: Currently, tumor-treating field (TTField) therapy utilizes a single "optimal" frequency of electric fields to achieve maximal cell death in a targeted population of cells. However, because of differences in cell size, shape, and ploidy during mitosis, optimal electric field characteristics for universal maximal cell death may not exist. This study investigated the anti-mitotic effects of modulating electric field frequency as opposed to utilizing uniform electric fields. METHODS: We developed and validated a custom device that delivers a wide variety of electric field and treatment parameters including frequency modulation. We investigated the efficacy of frequency modulating tumor-treating fields on triple-negative breast cancer cells compared to human breast epithelial cells. RESULTS: We show that frequency-modulated (FM) TTFields are as selective at treating triple-negative breast cancer (TNBC) as uniform TTFields while having a greater efficacy for combating TNBC cell growth. TTField treatment at a mean frequency of 150 kHz with a frequency range of ± 10 kHz induced apoptosis in a greater number of TNBC cells after 24 h as compared to unmodulated treatment which led to further decreased cell viability after 48 h. Furthermore, all TNBC cells died after 72 h of FM treatment while cells that received unmodulated treatment were able to recover to cell number equivalent to the control. CONCLUSION: TTFields were highly efficacious against TNBC growth, FM TTFields showed minimal effects on epithelial cells similar to unmodulated treatment.

7.
Discov Oncol ; 14(1): 34, 2023 Mar 29.
Artículo en Inglés | MEDLINE | ID: mdl-36991198

RESUMEN

PURPOSE: Triple-negative breast cancer continues to be one of the leading causes of death in women, making up 7% of all cancer deaths. Tumor-treating electric fields are low-energy, low-frequency oscillating electric fields that induce an anti-proliferative effect on mitotic cells in glioblastoma multiforme, non-small cell lung cancer, and ovarian cancer. Little is known about effects of tumor-treating fields on triple-negative breast cancer and known research for tumor-treating fields only utilizes low (< 3 V/cm) electric field intensities. METHODS: We have developed an in-house field delivery device capable of high levels of customization to explore a much wider variety of electric field and treatment parameters. Furthermore, we investigated the selectivity of tumor-treating field treatment between triple-negative breast cancer and human breast epithelial cells. RESULTS: Tumor-treating fields show greatest efficacy against triple-negative breast cancer cell lines between 1 and 3 V/cm electric field intensities while having little effect on epithelial cells. CONCLUSION: These results provide a clear therapeutic window for tumor-treating field delivery to triple-negative breast cancer.

8.
Nanomaterials (Basel) ; 12(20)2022 Oct 13.
Artículo en Inglés | MEDLINE | ID: mdl-36296779

RESUMEN

A simulation of quantum dot (QD) energy levels was designed to reproduce a quantum mechanical analytic method based on perturbation theory. A Schrödinger equation describing an electron-hole pair in a QD was solved, in consideration of the heterogeneity of the material parameters of the core and shell. The equation was solved numerically using single-particle basis sets to obtain the eigenstates and energies. This approach reproduced an analytic solution based on perturbation theory, while the calculation was performed using a numerical method. Owing to the effectiveness of the method, QD behavior according to the core diameter and external electric field intensity could be investigated reliably and easily. A 9.2 nm diameter CdSe/ZnS QD with a 4.2 nm diameter core and 2.5 nm thick shell emitted a 530 nm green light, according to an analysis of the effects of core diameter on energy levels. A 4 nm redshift at 5.4×105 V/cm electric field intensity was found while investigating the effects of external electric field on energy levels. These values agree well with previously reported experimental results. In addition to the energy levels and light emission wavelengths, the spatial distributions of wavefunctions were obtained. This analysis method is widely applicable for studying QD characteristics with varying structure and material compositions and should aid the development of high-performance QD technologies.

9.
Front Microbiol ; 13: 997732, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36246218

RESUMEN

In the past decade, studies on the remediation of heavy metals contaminated soil by microbial fuel cells (MFCs) have attracted broad attention because of the self-generated power and their multifield principles such as the extracellular electron transfer (EET) reduction, electromigration for heavy metals removal. However, given the bio electro-motive power from soil MFCs is weak and fluctuated during the remediation, we need to comprehensively understand the origination of driving force in MFC based on the analysis of the fundamental rationale of ion moving in cells and improve the performance via the appropriate configurations and operations. In this review, we first described the structures of soil MFCs for heavy metals remediation and compared the advantages of different types of configurations. Then, based on the theoretical models of heavy metal migration, enrichment, and reduction in soil MFCs, the optimization of soil MFCs including the length of the remediation area, soil conductivity, control of electrode reaction, and modification of electrodes were proposed. Accordingly, this review contributes to the application of bioelectrochemistry to efficiently remove heavy metals from soils.

10.
Entropy (Basel) ; 24(5)2022 May 20.
Artículo en Inglés | MEDLINE | ID: mdl-35626609

RESUMEN

This work investigates the temporal statistical structure of time series of electric field (EF) intensity recorded with the aim of exploring the dynamical patterns associated with periods with different human activity in urban areas. The analyzed time series were obtained from a sensor of the EMF RATEL monitoring system installed in the campus area of the University of Novi Sad, Serbia. The sensor performs wideband cumulative EF intensity monitoring of all active commercial EF sources, thus including those linked to human utilization of wireless communication systems. Monitoring was performed continuously during the years 2019 and 2020, allowing us to investigate the effects on the patterns of EF intensity of varying conditions of human mobility, including regular teaching and exam activity within the campus, as well as limitations to mobility related to the COVID-19 pandemic. Time series analysis was performed using both simple statistics (mean and variance) and combining the information-theoretic measure of information storage (IS) with the method of surrogate data to quantify the regularity of EF dynamic patterns and detect the presence of nonlinear dynamics. Moreover, to assess the possible coexistence of dynamic behaviors across multiple temporal scales, IS analysis was performed over consecutive observation windows lasting one day, week, month, and year, respectively coarse grained at time scales of 6 min, 30 min, 2 h, and 1 day. Our results document that the EF intensity patterns of variability are modulated by the movement of people at daily, weekly, and monthly scales, and are blunted during periods of restricted mobility related to the COVID-19 pandemic. Mobility restrictions also affected significantly the regularity of the EF intensity time series, resulting in lower values of IS observed simultaneously with a loss of nonlinear dynamics. Thus, our analysis can be useful to investigate changes in the global patterns of human mobility both during pandemics or other types of events, and from this perspective may serve to implement strategies for safety assessment and for optimizing the design of networks of EF sensors.

11.
AMB Express ; 11(1): 47, 2021 Mar 23.
Artículo en Inglés | MEDLINE | ID: mdl-33759040

RESUMEN

Pulsed electric fields (PEF) as a new pasteurization technology played an important role in the process of inactivating microorganisms. At the same time, temperature could promote the process of electroporation, and achieve better inactivation effect. This article studied the inactivation effect of PEF on Saccharomyces cerevisiae, Escherichia coli, and Bacillus velezensis under different initial temperatures (room temperature-24 [Formula: see text], 30 [Formula: see text], 40 [Formula: see text], 50 [Formula: see text]). From the inactivation results, it found temperature could reduce the critical electric field intensity for microbial inactivation. After the irreversible electroporation of microorganisms occurred, the nucleic acid content and protein content in the suspension increased with the inactivation rate because the cell membrane integrity was destroyed. We had proved that the electric field and temperature could promote molecular transport through the finite element simulation. Under the same initial temperature and electrical parameters (electric field intensity, pulse width, pulse number), the lethal effect on different microorganisms was Saccharomyces cerevisiae > Escherichia coli > Bacillus velezensis.

12.
Chemosphere ; 261: 128046, 2020 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-33113656

RESUMEN

Compared with conventional sludge reduction techniques, electric field assisted membrane bioreactor (MBR) is a cost-effective technology with low power consumption. In this study, spontaneous electric field without extra power supply was introduced into the MBR for wastewater treatment to complete the in situ sludge reduction and membrane fouling mitigation. A novel spontaneous electric field membrane bioreactor (SEF-MBR) equipped with Cu-nanowires (Cu-NWs) conductive microfiltration membrane as cathode was established by using baffles to form anaerobic and aerobic tanks. SEF-MBR 1 with external resistance of 500 Ω maintained a highest electric field intensity of 1.25 mV/cm. Compared with Control-MBR, the reduction of mixed liquor suspended solids (MLSS) growth rate, extracellular polymeric substances (EPS) growth rate, total cell number and water content of SEF-MBR 1 reached 50.0%, 43.0%, 37.1% and 6.4%, respectively. After 43 days operation, SEF-MBR 1 obtained the minimum MLSS concentration and sludge volume, which were 29.9% and 83.8% lower than that of it in Control-MBR. The total biovolume of the contaminants (i.e., EPS and cells) on the membrane surface of SEF-MBR 1 was 68.8% lower than that of Control-MBR. SEF-MBR 1 exhibited a better performance with a lower membrane fouling rate (0.58 kPa/d) than Control-MBR (1.09 kPa/d). Economic analysis showed that a total of 148.1 kWh/m3 of electric energy was saved in the SEF-MBR 1. This technology reduced the sludge production in the sewage biological treatment process, which realized the sludge reduction had a positive impact on the membrane fouling mitigation.


Asunto(s)
Incrustaciones Biológicas/prevención & control , Reactores Biológicos/microbiología , Electricidad , Membranas Artificiales , Nanocables , Aguas del Alcantarillado/análisis , Electrodos , Matriz Extracelular de Sustancias Poliméricas/química , Aguas del Alcantarillado/microbiología , Aguas Residuales/química , Aguas Residuales/microbiología
13.
Water Res ; 171: 115452, 2020 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-31901683

RESUMEN

The electric field assisted membrane bioreactor (MBR) is an effective technique to alleviate membrane fouling. In this study, the spontaneous electric field was introduced into the MBR to observe the growth process of cake layer on the membrane surface. The external resistance for spontaneous electric field MBR (S-50) and S-500 were 50 Ω and 500 Ω respectively. During the experiments, S-50 maintained the highest electric field intensity of 11.83 mV/cm. The reduction of extracellular polymeric substances (EPS) content in activated sludge, transmembrane pressure (TMP) growth rate reached 52.8% and 51.7% respectively. After 28 days operation, S-50 obtained the minimum contaminant specific biovolume (23.316 µm3/µm2), which was 68.2% lower than that of it in Control-MBR. The metal oxide or metal hydroxide were distributed in the cake layer. EPS played a significant role in the formation and growth of the cake layer. Based on the results obtained in this study, the growth of the biofouling layer on the membrane surface could be divided into three stages. EPS first deposited on the membrane surface, and then microorganisms embedded in the cake layer to form clusters. After that, EPS and total cells further increased and led to a faster biovolume growth rate. Subsequently, the biovolume growth rate decreased in the cake layer. The spontaneous electric field delayed the deposition of EPS on the membrane surface. The produced H2O2 and •OH were beneficial to the degradation of organics, causing the smaller contaminant biovolume on the membrane surface. This work aims to provide a theoretical basis for the practical application of the electric field to control membrane fouling.


Asunto(s)
Incrustaciones Biológicas , Membranas Artificiales , Reactores Biológicos , Peróxido de Hidrógeno , Aguas del Alcantarillado
14.
Chemosphere ; 237: 124527, 2019 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-31549649

RESUMEN

Electrochemical reduction of CO2 has been demonstrated as one of the promising technologies to reduce the greenhouse effect. In this study, nano-prism assembled hierarchical CuO microspheres (Prism-CuO) were designed and used for CO2 electroreduction. The Prism-CuO coated gas diffusion electrode showed high activity for CO2-to-formate conversion with overpotential as low as ∼200 mV, and achieved maximum faradaic efficiency of 65.1% at -1.6 V vs. Ag/AgCl. Moreover, it maintained the stable performance for continuous 20 h of electrolysis. The better performance was mainly attributed to the unique prism feature as it provided abundant corner- and edge-based low-coordinated active reaction sites. These sites could further arouse strong local-electric field to lower the barrier of CO2 adsorption and motivate CO2 activation by accelerating charges transfer process. The result implied designing the nano-prism constructed hierarchical framework would be an efficient strategy to develop the advanced electrocatalyst for efficient CO2 reduction in aqueous solution.


Asunto(s)
Dióxido de Carbono/química , Cobre/química , Microesferas , Adsorción , Catálisis , Difusión , Técnicas Electroquímicas , Electrodos , Formiatos , Oxidación-Reducción
15.
ACS Chem Neurosci ; 10(1): 348-357, 2019 01 16.
Artículo en Inglés | MEDLINE | ID: mdl-30212623

RESUMEN

The strategy of using electrical stimulation (ES) to promote the neural differentiation and regeneration of injured nerves is proven feasible. Study of the possible molecular mechanisms in relation to this ES promotion effect should be helpful for understanding the phenomenon. In this study, it was identified that the neuronal differentiation of PC12 cells was enhanced when the electric field intensity was in the range of 30-80 mV/mm, and a lower or higher electric-field intensity displayed inferior effects. Under ES, however, levels of intracellular reactive oxygen species (ROS), intracellular Ca2+ dynamics, and expression of TREK-1 were measured as being gradually increasing alongside higher electric-field intensity. In trying to understand the relationship between the ES enhancement on differentiation and these variations in cell activities, parallel experiments were conducted by introducing exogeneous H2O2 into culture systems at different concentrations. Similarly, the effects of H2O2 concentration on the neuronal differentiation of PC12 cells, intracellular ROS and Ca2+ levels, and TREK-1 expression were systematically characterized. In comparative studies, it was found in two cases that ES of 50 mV/mm for 2 h/day and H2O2 of 5 µM in culture medium shared comparable results for intracellular ROS and Ca2+ levels and TREK-1 expression. Higher H2O2 concentrations (e.g., 10 and 20 µM) demonstrated adverse effects on cell differentiation and caused DNA damage. A stronger ES (e.g., 100 mV/mm), being associated with a higher intracellular ROS level, also resulted in weaker enhancement of the neuronal differentiation of PC12 cells. These facts suggested that the intracellular ROS generated under ES might be an intermediate signal transducer involved in cascade reactions relative to cell differentiation.


Asunto(s)
Diferenciación Celular/fisiología , Daño del ADN/fisiología , Especies Reactivas de Oxígeno/metabolismo , Animales , Diferenciación Celular/efectos de los fármacos , Daño del ADN/efectos de los fármacos , Estimulación Eléctrica/métodos , Peróxido de Hidrógeno/toxicidad , Células PC12 , Ratas
16.
Biomed Eng Online ; 17(1): 71, 2018 Jun 05.
Artículo en Inglés | MEDLINE | ID: mdl-29866126

RESUMEN

BACKGROUND: Intra-body communication (IBC) is one of the highlights in studies of body area networks. The existing IBC studies mainly focus on human channel characteristics of the physical layer, transceiver design for the application, and the protocol design for the networks. However, there are few safety analysis studies of the IBC electrical signals, especially for the galvanic-coupled type. Besides, the human channel model used in most of the studies is just a multi-layer homocentric cylinder model, which cannot accurately approximate the real human tissue layer. METHODS: In this paper, the empirical arm models were established based on the geometrical information of six subjects. The thickness of each tissue layer and the anisotropy of muscle were also taken into account. Considering the International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines, the restrictions taken as the evaluation criteria were the electric field intensity lower than 1.35 × 104 f V/m and the specific absorption rate (SAR) lower than 4 W/kg. The physiological electrode LT-1 was adopted in experiments whose size was 4 × 4 cm and the distance between each center of adjoining electrodes was 6 cm. The electric field intensity and localized SAR were all computed by the finite element method (FEM). The electric field intensity was set as average value of all tissues, while SAR was averaged over 10 g contiguous tissue. The computed data were compared with the 2010 ICNIRP guidelines restrictions in order to address the exposure restrictions of galvanic-coupled IBC electrical signals injected into the body with different amplitudes and frequencies. RESULTS: The input alternating signal was 1 mA current or 1 V voltage with the frequency range from 10 kHz to 1 MHz. When the subject was stimulated by a 1 mA alternating current, the average electric field intensity of all subjects exceeded restrictions when the frequency was lower than 20 kHz. The maximum difference among six subjects was 1.06 V/m at 10 kHz, and the minimum difference was 0.025 V/m at 400 kHz. While the excitation signal was a 1 V alternating voltage, the electric field intensity fell within the exposure restrictions gradually as the frequency increased beyond 50 kHz. The maximum difference among the six subjects was 2.55 V/m at 20 kHz, and the minimum difference was 0.54 V/m at 1 MHz. In addition, differences between the maximum and the minimum values at each frequency also decreased gradually with the frequency increased in both situations of alternating current and voltage. When SAR was introduced as the criteria, none of the subjects exceeded the restrictions with current injected. However, subjects 2, 4, and 6 did not satisfy the restrictions with voltage applied when the signal amplitude was ≥ 3, 6, and 10 V, respectively. The SAR differences for subjects with different frequencies were 0.062-1.3 W/kg of current input, and 0.648-6.096 W/kg of voltage input. CONCLUSION: Based on the empirical arm models established in this paper, we came to conclusion that the frequency of 100-300 kHz which belong to LF (30-300 kHz) according to the ICNIRP guidelines can be considered as the frequency restrictions of the galvanic-coupled IBC signal. This provided more choices for both intensities of current and voltage signals as well. On the other hand, it also makes great convenience for the design of transceiver hardware and artificial intelligence application. With the frequency restrictions settled, the intensity restrictions that the current signal of 1-10 mA and the voltage signal of 1-2 V were accessible. Particularly, in practical application we recommended the use of the current signals for its broad application and lower impact on the human tissue. In addition, it is noteworthy that the coupling structure design of the electrode interface should attract attention.


Asunto(s)
Electricidad , Análisis de Elementos Finitos
17.
Bioresour Technol ; 234: 370-379, 2017 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-28343056

RESUMEN

Under microwave irradiation, raw sludge was pyrolyzed mainly by evaporation of water, with a weight loss ratio of 84.8% and a maximum temperature not exceeding 200°C. High-temperature pyrolysis of SiC sludge could be realized, with a weight loss ratio of 93.4% and a final pyrolysis temperature of 1131.7°C. Variations between the electric field intensity distribution are the main reason for the differences of pyrolysis efficiencies. HFSS simulation showed that the electric field intensity of the raw sludge gradually decreased from 2.94×104V/m to 0.88×104V/m when pyrolysis ends, while that of SiC sludge decreased from 3.73×104V/m at the beginning to 1.28×104V/m, then increased to 4.03×104V/m. The electromagnetic effect is the main factor (r≥0.91) influencing the temperature increase and weight loss of raw sludge. Both the electromagnetic effect and heat conduction effect influenced temperature rise and weight loss of SiC sludge, but the former's influence was comparatively larger.


Asunto(s)
Aguas del Alcantarillado/química , Compuestos Inorgánicos de Carbono/química , Desecación , Campos Electromagnéticos , Calor , Microondas , Compuestos de Silicona/química , Administración de Residuos/métodos
18.
J Food Sci Technol ; 53(3): 1371-1379, 2016 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-30279610

RESUMEN

This study was carried out to evaluate the effect of PEF process using static treatment chamber on fresh sugarcane juice with and without addition of lemon and ginger with respect to microbial content, chemical properties, nutrient content and shelf life extention of the product. The fresh sugar cane juice without addition of lemon and ginger treated at different field strengths (30 kV cm-1 and 50 kV cm-1) and different pulse numbers (150, 300) was initially investigated by storage at room temperature (31 °C) and refrigeration temperature (4 °C) for 30 days. The PEF effect on fresh sugar cane juice at room temperature and refrigerated temperature was compared with untreated sample (31 °C). At the end of the storage period samples treated at field strength 30 kV cm-1, 150 pulses were found to be stable compared with untreated sample. The second experimental study of PEF process was done on fresh sugarcane juice with the addition of lemon and ginger for fourteen days at different electric field intensities (10 kV cm-1, 20 kV cm-1 and 30 kV cm-1) with the same pulse number (150 pulses) and stored 4 °C. Even better reduction of microbes was achieved with PEF treatment condition of field strength 20 kV cm-1, 150 pulses in the presence of lemon and ginger. The sensory attributes of untreated fresh sugarcane juice were maintained up to only two days, but for the PEF treated sample, shelf life was extened up to seven days. Further, addition of lemon and ginger in the PEF treated sugarcane juice doubled the shelf life up to fourteen days.

19.
Sensors (Basel) ; 16(1)2015 Dec 30.
Artículo en Inglés | MEDLINE | ID: mdl-26729119

RESUMEN

A voltage transformer, as voltage signal detection equipment, plays an important role in a power system. Presently, more and more electric power systems are adopting potential transformer and capacitance voltage transformers. Transformers are often large in volume and heavyweight, their insulation design is difficult, and an iron core or multi-grade capacitance voltage division structure is generally adopted. As a result, the detection accuracy of transformer is reduced, a huge phase difference exists between detection signal and voltage signal to be measured, and the detection signal cannot accurately and timely reflect the change of conductor voltage signal to be measured. By aiming at the current problems of electric transformation, based on electrostatic induction principle, this paper designed a non-contact voltage sensor and gained detection signal of the sensor through electrostatic coupling for the electric field generated by electric charges of the conductor to be measured. The insulation structure design of the sensor is simple and its volume is small; phase difference of sensor measurement is effectively reduced through optimization design of the electrode; and voltage division ratio and measurement accuracy are increased. The voltage sensor was tested on the experimental platform of simulating three-phase transmission line. According to the result, the designed non-contact voltage sensor can realize accurate and real-time measurement for the conductor voltage. It can be applied to online monitoring for the voltage of three-phase transmission line or three-phase distribution network line, which is in accordance with the development direction of the smart grid.

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