Vietnam Academy of Science and Technology: Journals Online
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MATERIAL FLOW ANALYSIS FOR PRODUCTION LINE AND WASTEWATER TREATMENT IN BREWERY INDUSTRY, AND RECOMMENDATIONS FOR CLEANER PRODUCTION SOLUTIONS
No full textThe novelty of this study is to apply Material Flow Analyses (MFAs) for both production line and wastewater treatment processes in a modern-technology beer company with an aim to assess cleaner production opportunities and potentials of the company through different scenarios for each cleaner production measure. As aspect of production line, two energy saving measures were proposed: (1) to reuse water-for-cooling for bottle and keg washing, and (2) to reuse thermal heat produced during rapid cooling to supply heat for the malt pasting process. The 2nd measure could save 11% of heat needed for malt pasting and 5.5% of steam from boiler that heats keg washing water was reduced in the 1nd solution compared to the case of no heat reuse in loop. Within the wastewater treatment plant (WWTP), the study proposed using biogas to generate energy through CHP (combine heat and power) system, of which electrical power is utilized for the WWTP operation and heat is used to maintain the temperature of sludge anaerobic digester (SAD) through a heat exchanger (HE). The results showed that the energy generated from biogas could compensate 16% of the total energy consumption of the WWTP with 43% (corresponding to 1,735 kWh) of electrical energy saving; 11% of heat saving to maintain SAD syste
Experimental Verification of a TH Multi-band Metamaterial Absorber
No full textMulti-band metamaterial absorbers have been of great interest owing to their potentials for a wide range of communicating, sensing, imaging, and energy harvesting applications. In this work, we experimentally investigate a four-band metamaterial absorber operating at THz frequencies. The metamaterials are fabricated using the maskless UV photolithography and e-beam evaporation techniques. The absorption spectra of the proposed absorber are measured using the micro-Fourier transformed infrared spectroscopy. It was demonstrated that multi-band absorption behavior originates from different individual metamaterial resonators. The thickness of the dielectric spacer plays a key role in optimizing the absorption performance, in line with the predicted results on single-band THz absorbers
Effect of Molecular Charge Asymmetry on Even-to-odd Ratio of High-order Harmonic Generation
Get PDFRecently, asymmetric molecules, such as HeH, CO, OCS, HCl, have been evolved much attention since its rich information in the high-order harmonic generation (HHG), whose ratio of adjacent even and odd harmonics characterizes the asymmetry of molecules. In this paper, we study the dependence of even-to-odd ratio on the asymmetric parameters, in particular, the nuclear-charge ratio, and the permanent dipole, by exploiting a simple but general model of asymmetric molecules subjected to an intense laser pulse. The HHG is simulated by the numerical method of solving the time-dependent Schrödinger equation. We find out that this even-to-odd ratio strongly depends on the nuclear-charge ratio. In particular, the even-to-odd ratio reaches its maximum when the nuclear-charge ratio is about from 0.5 to 0.7. Besides, the dependence on the permanent dipole of the even-to-odd ratio has a non-trivial law. To explain, we calculate the analytical ratio of the transition dipole according to the emission of even and odd harmonics, and this ratio is well consistent with the even-to-odd ratio of the HHG
Using Solvent Vapor Annealing for the Enhancement of the Stability and Efficiency of Monolithic Hole-conductor-free Perovskite Solar Cells
Get PDFIn the last few years, perovskite solar cells have attracted enormous interest in the photovoltaic community due to their low cost of materials, tunable band gap, excellent photovoltaic properties and easy process ability at low temperature. In this work, we fabricated hole-conductor-free carbon-based perovskite solar cells with the monolithic structure: glass/FTO/bl-TiO/(mp-TiO/mp-ZrO/mp-carbon) perovskite. The mixed 2D/3D perovskite precursor solution composed of PbI, methylammonium iodide (MAI), and 5-ammoniumvaleric acid iodide (5-AVAI) was drop-casted through triple mesoporous TiO/ZrO/carbon electrode films. We found that the isopropyl alcohol (IPA) solvent vapor annealing strongly influenced on the growth of mixed 2D/3D perovskite on triple mesoscopic layers. It resulted in the better pore filling, better crystalline quality of perovskite layer, thus the improved stability and efficiency of perovskite solar cell was attributed to lower defect concentration and reduced recombination
Full Electroweak Radiative Corrections to with Initial Beam Polarization Effects
No full textWe calculate full electroweak radiative corrections and initial state radiation (ISR) corrections to with initial beam polarization effects. In phenomenological results, we study the impact of electroweak and ISR corrections on cross-sections as well as their relevant distributions. We find that the corrections are order of 10% contributions. They are sizable contributions and should be taken into account at future lepton colliders
Inverse scattering problems and their application to nonlinear integrable equations
Get PDFThe monograph entitled “Inverse Scattering Problems and Their Application to Nonlinear Integrable Equations” has been published by CRC–Press Taylor Francis Group in November 2019 at the website: https://www.taylorfrancis.com/books/9780429328459. This monograph is devoted to inverse scattering problems for differential equations and their application to nonlinear evolution equations. It contains most of published papers of Prof. Pham Loi Vu, which are mentioned in the Introduction and at the beginning of every chapter of the book. Prof. Dr. Sci. Pham Loi Vu, born in 1934, is a professor of Institute of Mechanics, Vietnam Academy of Science and Technology
Expression of gene encoding flavonol synthase isolating from trung du xanh tea (Camellia sinensis var. macrophylla) in E. coli
Get PDFCommon flavonols in plants including quercetin, kaempferol and myricetin are synthesized from dihydroflavonols (dihydroquercetin-DHQ, dihydrokaempferol-DHK and dihydromyricetin-DHM) by flavonol synthase (FLS). In tea, FLS has been shown to metabolize dihydroquercetin to quercetin. The FLS gene was cloned and sequenced from the cultivated tea (Camellia sinensis var. macrophylla) in Thai Nguyen province. In this study, we presented the results of optimizing and designing an expression vector for recombinant FLS (recombinant FLS-rFLS). The FLS gene was ligated completely to the pET32a (+) vector, then expressed in E. coli Rosetta1 and Rosetta2 strain. Using 1mM IPTG to induce the expression of rFLS at 37oC, rFLS was obtained with 52.83 kDa in size and existed predominantly as insoluble form. E. coli Rosetta1 pET32a (+)_FLSproduces rFLS in the soluble fraction than E. coli Rosetta2 pET32a (+)_FLS. Next, E. coli Rosetta1 pET32a (+)_FLSwas optimized for expression at temperatures of 30oC, 23oC and 16oC (24 and 48 hours). After being induced for expression with 1mM IPTG in 48 hours and cultured at 16oC, E. coli Rosetta1 strain containing pET32a (+) FLS produced the largest amount of rFLS in the soluble form.
Role of GmNAC019 transcription factor in salinity and drought tolerance of transgenic Arabidopsis thaliana
Get PDFIncreasingly severe drought and salinity stress due to global climate change have made these stresses bigger threats to ecosystem and agriculture. Previous studies reported that GmNAC019, a soybean NAC transcription factor - encoding gene, displayed induced expression upon drought treatment in wild-type cultivars. In this study, drought and salinity stresses were applied on GmNAC019-overexpressing Arabidopsis plants to verify the contribution of GmNAC019 in regulating plant response to the stress conditions. Results from the water loss rate and survival rate assays revealed that the transgenic line conferred improved tolerance to drought stress as evidenced by lower leaf water loss and significantly higher rate of survival than seen in the wild-type plants. Similarly, the survival rate assay for testing salinity effects on plants by growing the plants on MS medium supplemented with different NaCl concentrations also indicated that the transgenic plants had a better tolerance to salt stress as they displayed lower rate of root growth inhibition and higher survival rate. Taken these results altogether, it is suggested that GmNAC019 might play important role in aiding plant response to drought and salinity stresses. Specific functions of this gene should be elaborated in future studies to evaluate its potential application for crop improvement
Cellobiose-dehydrogenase production by some fungal species isolated in rain forests of Northern Vietnam
No full text Fungal enzymes are well-known as effective in hydrolyze lignocellulose-rich materials. This decomposition process requires many enzymes to participate in a coordinated factor to hydrolyze the polymer structure. Among them, there are some of popular oxidized enzymes such as lignin peroxidase, mangan peroxidase and laccase. Cellobiose dehydrogenase (CDH) is an extracellular enzyme found in various fungi, it was first discovered in 1974 by Westermark in white rot fungus Trametes verscolor and Phanerochaete chrysosporium. The biological role of CDH has been proven to participate in the decomposition of natural polymers such as cellulose, hemicellulose and lignin by generating hydroxyl radical through Fenton reaction. CDH has unique biochemical and catalytic properties that have been used in biosensors to detect cellodextrin, maltose, lactose and diphenol compounds or in biomedical applications such as lactobionic acid production. Therefore, CDH is an important component of the extracellular enzyme system for lignocellulose decomposition. In this study, 47 fungal strains isolated from rainforests of Cuc Phuong and Muong Phang National Parks and screened for CDH activity. Of which, 33 active fungi exhibited CDH activity from 8.89 to 74.4 U/L during growth on solid medium with rice straw as raw substrate. The highest enzyme production was identified for Coprinellus aureogranulatus (MPG14) reach 77.4 U/L on basic medium and its CDH activity of up to 237.4 U/L under optimal condition: supplemented with carbon source of α- cellulose (20 g/L), nitrogen source (5 g/L peptone) incubated for 12 days at 30℃, pH 5.5 and 200 rpm after inoculation. Thus, the fungus has the potential to exploit the CDH enzyme applied in the pretreatment of lignocellulose-rich materials.
MATERIAL FLOW ANALYSIS (MFA) AND ENERGY BALANCE ANALYSIS (EBA) AS TECHNICAL TOOLS FOR WASTEWATER POLLUTION CONTROL IN TEXTILE AND DYEING INDUSTRY – A CASE STUDY
Get PDFThe textile and dyeing industry consumes a large amount of water and discharges to the environment many pollutants including dyestuffs, auxiliaries, others. In this study, a selected textile and dyeing company was representing modern factory in Vietnam. Using STAN software, the authors have quantified and analyzed the material flows of the production lines and of the main pollutants in wastewater. Comparing with “business as usual” scenario, a new scenario with treatment and reuse of wastewater has been introduced. The discharge volume of wastewater from company was about 3,608.96 m3/day (or 1,317,270.4 m3/year). Loadings of the main pollutants in wastewater as COD, TSS, T-P and T-N were 1419.95, 1571.36, 17.77 and 50.16 ton/year, respectively. One meter of produced fabric consumes 0.025 m3 of water. Energy consumption of the wastewater treatment station was analyzed by SANKEY software. The energy consumption rate was 1.695 kWh per m3 of wastewater. Reuse of wastewater could save 1,129.05 kWh per day of electricity and 1,804.48 m3 per day of fresh water to be taken from the river source. Ozonation was the most consuming energy process at the wastewater treatment station, accounting for 58.88% of total wastewater treatment energy consumption