Records Added in 2020
Records added in 2020
Change year: 2018 | 2019 | 2020
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Showing records 1 to 25 of 243. [First] Page: 1 2 3 4 5 Last
Screening of Amino Acids and Surfactant as Hydrate Promoter for CO2 Capture from Flue Gas
Jyoti Shanker Pandey, Yousef Jouljamal Daas, Nicolas von Solms
February 12, 2020 (v1)
Keywords: amino acids, Carbon Dioxide Capture, flue gas hydrate, sodium dodecyl sulfate
In this study, the kinetics of flue gas hydrate formation in bulk water in the presence of selected amino acids and surfactants are investigated. Four amino acids (3000 ppm) are selected based on different hydropathy index. Constant-ramping and isothermal experiments at 120 bar pressure and 1 °C temperature are carried out to compare their hydrate promotion capabilities with surfactant sodium dodecyl sulfate (SDS) (500−3000 ppm) and water. Based on experimental results, we report the correlation between hydrate promotion capability of amino acids and their hydrophobicity. Hydrophobic amino acids show stronger flue gas hydrate promotion capability than water and hydrophilic amino acids. We discuss the controlling mechanisms to differentiate between promoters and inhibitors’ roles among the amino acids. Between 2000−3000 ppm concentrations, hydrophobic amino acids have near similar promotion capabilities as SDS. This research highlights the potential use of amino acids as promoters or in... [more]
Numerical Study on the Influence of Inlet Guide Vanes on the Internal Flow Characteristics of Centrifugal Pump
Peifeng Lin, Yongzheng Li, Wenbin Xu, Hui Chen, Zuchao Zhu
February 12, 2020 (v1)
Keywords: centrifugal pump, inlet guide vanes, offset angle, the pressure fluctuation frequency
In order to make the centrifugal pump run efficiently and stably under various working conditions, the influences of the incoming vortex flow in the inlet pipe on the main flow in the impeller is studied numerically, based on the k − ω SST turbulence model. Some guide vanes with different offset angle were added to change the statistical characteristic of the internal flow in the inlet pipe of the centrifugal pump. Both contour distributions of internal flow and statistical results of external performance are obtained and analyzed. The results show that the existence of vanes can divide the large vortex because of the reversed flow from the rotating impeller at low flow rate conditions into small vortices, which are easier to dissipate, make the velocity and pressure distribution more uniform, improve the stability of the flow in the impeller, reduce the hydraulic loss, and improve the hydraulic performance of the pump. The pump with vanes of offset angle 25° has a small pressu... [more]
Modeling and Exploiting Microbial Temperature Response
Philipp Noll, Lars Lilge, Rudolf Hausmann, Marius Henkel
February 12, 2020 (v1)
Keywords: bioprocess engineering, calorimetry, monitoring and control, temperature modeling, thermal growth curve, thermoregulation
Temperature is an important parameter in bioprocesses, influencing the structure and functionality of almost every biomolecule, as well as affecting metabolic reaction rates. In industrial biotechnology, the temperature is usually tightly controlled at an optimum value. Smart variation of the temperature to optimize the performance of a bioprocess brings about multiple complex and interconnected metabolic changes and is so far only rarely applied. Mathematical descriptions and models facilitate a reduction in complexity, as well as an understanding, of these interconnections. Starting in the 19th century with the “primal” temperature model of Svante Arrhenius, a variety of models have evolved over time to describe growth and enzymatic reaction rates as functions of temperature. Data-driven empirical approaches, as well as complex mechanistic models based on thermodynamic knowledge of biomolecular behavior at different temperatures, have been developed. Even though underlying biological... [more]
Characteristics of Low-Temperature Polyvinyl Chloride Carbonization by Catalytic CuAl Layered Double Hydroxide
Erwei Pang, Weijun Liu, Shuhua Zhang, Nengshuo Fu, Zhongxun Tian
February 12, 2020 (v1)
Keywords: catalytic PVC pyrolysis, CuAl layered double hydroxide (CuAl-LDH), PVC carbonization
A good way to make carbon materials was presented in low-temperature polyvinyl chloride (PVC) carbonization by catalysis. The process of low-temperature PVC carbonization by CuAl-layered double hydroxide (CuAl-LDH) was investigated by thermogravimetric analysis (TGA) and tubular furnace. The results show that CuAl-LDH accounting for 5% of PVC mass enabled acceleration of the dehydrochlorination in PVC as soon as possible and maximized the yield of the PVC carbonized product. The vacuum with 0.08 MPa, 20 °C/min heating rate and 90 min carbonized maintenance time were optimal for PVC carbonization. Moreover, the best morphology and yield of the carbonized product was provided at a carbonization temperature of 300 °C.
Energy and Material Flows and Carbon Footprint Assessment Concerning the Production of HMF and Furfural from a Cellulosic Biomass
Hannes Schöppe, Peter Kleine-Möllhoff, Rolf Epple
February 12, 2020 (v1)
Subject: Energy Policy
Keywords: 5-hydroxymethylfurfural, bio-based chemical production, carbon footprint, furfural, HMF, material and energy flows
5-hydroxymethyl-furfural (HMF) and furfural are interesting as potential platform chemicals for a bio-based chemical production economy. Within the scope of this work, the process routes under technical development for the production of these platform chemicals were investigated. For two selected processes, the material and energy flows, as well as the carbon footprint, were examined in detail. The possible production process optimizations, further development potentials, and the research demand against the background of the reduction of the primary energy expenditure were worked out.
Polyetherimide-Montmorillonite Nano-Hybrid Composite Membranes: CO2 Permeance Study via Theoretical Models
Asif Jamil, Oh Pei Ching, Muhammad Naqvi, Hafiza Aroosa Aslam Khan, Salman Raza Naqvi
February 12, 2020 (v1)
Subject: Materials
Keywords: bharadwaj, CO2 permeation, composite membranes, hollow fibre, montmorillonite, polyetherimide
The incorporation of aminolauric acid modified montmorillonite (f-MMT) in polyetherimide (PEI) has been implemented to develop hollow fibre nano-hybrid composite membranes (NHCMs) with improved gas separation characteristics. The aforementioned characteristics are caused by enhanced f-MMT spatial dispersion and interfacial interactions with PEI matrix. In this study, existing gas permeation models such as, Nielsen, Cussler, Yang−Cussler, Lape−Cussler and Bharadwaj were adopted to estimate the dispersion state of f-MMT and to predict the CO2 permeance in developed NHCMs. It was found out that the average aspect ratio estimated was 53, with 3 numbers of stacks per unit tactoid, which showed that the intercalation f-MMT morphology is the dominating dispersion state of filler in PEI matrix. Moreover, it was observed that Bharadwaj model showed the least average absolute relative error (RE) values till 3 wt. % f-MMT loading in the range of ±10 for a pressure range of 2 to 10 bar. Hence, Bha... [more]
Controllability Comparison of the Four-Product Petlyuk Dividing Wall Distillation Column Using Temperature Control Schemes
Xing Qian, Rui Liu, Kejin Huang, Haisheng Chen, Yang Yuan, Liang Zhang, Shaofeng Wang
February 12, 2020 (v1)
Keywords: dividing wall distillation column (DWDC), extended Petlyuk DWDC, simplified double temperature difference control (SDTDC), simplified temperature difference control (STDC), temperature control (TC)
An effective process intensification strategy based on dividing walls shows promising energy-saving results for distillation processes. The three-product Petlyuk dividing wall distillation columns (DWDCs) are able to save approximately 30% energy in comparison with the traditional distillation columns. Furthermore, the four-product extended Petlyuk DWDC reduces about 50% of operation costs than conventional distillation sequences. Although researchers have extensively studied control schemes for the three-product Petlyuk DWDC, relatively little work has been done on the four-product extended Petlyuk DWDC. This paper studies feasible temperature control schemes containing temperature control scheme (TC), simplified temperature difference control scheme (STDC), and simplified double temperature difference control scheme (SDTDC) for the four-product extended Petlyuk DWDC. STDC and SDTDC are introduced so as to improve the dynamic performances with simple control schemes. All three control... [more]
Plasmonic-Active Nanostructured Thin Films
Jay K. Bhattarai, Md Helal Uddin Maruf, Keith J. Stine
February 12, 2020 (v1)
Subject: Materials
Keywords: biosensing, gold nanostructures, lithography, localized surface plasmon resonance (LSPR), nanofabrication, nanohole array, plasmonics, thin film
Plasmonic-active nanomaterials are of high interest to scientists because of their expanding applications in the field for medicine and energy. Chemical and biological sensors based on plasmonic nanomaterials are well-established and commercially available, but the role of plasmonic nanomaterials on photothermal therapeutics, solar cells, super-resolution imaging, organic synthesis, etc. is still emerging. The effectiveness of the plasmonic materials on these technologies depends on their stability and sensitivity. Preparing plasmonics-active nanostructured thin films (PANTFs) on a solid substrate improves their physical stability. More importantly, the surface plasmons of thin film and that of nanostructures can couple in PANTFs enhancing the sensitivity. A PANTF can be used as a transducer for any of the three plasmonic-based sensing techniques, namely, the propagating surface plasmon, localized surface plasmon resonance, and surface-enhanced Raman spectroscopy-based sensing techniqu... [more]
Research on Green Power Dispatching Based on an Emergy-Based Life Cycle Assessment
Tao Li, Yi Miao Song, Ang Li, Jing Shen, Chao Liang, Ming Gao
February 12, 2020 (v1)
Subject: Energy Policy
Keywords: coal-fired power generation, Em-LCA evaluation, environmental impacts, green power dispatching, process management
Environmental protection pressures and green energy strategies have created major challenges for a cleaner production of China’s coal-fired power generation. Although China’s electric power dispatching department has tried to prioritize clean energy, the current dispatching models lack environmental indicators related to coal-fired power generation. The main purpose of this paper is to provide a comprehensive environmental indicator for the cleanliness evaluation of coal-fired power plants. In this paper, the (Emergy-based Life Cycle Assessment) Em-LCA method is used to measure and analyze environmental related resource consumption, socio-economic investment, and emissions in the whole life cycle of coal-fired power plants. At the same time, based on the above three environmental impacts in the whole life cycle, this paper constructs the (Em-LCA based Cleaner Production Comprehensive Evaluation) ECPCE index to guide a green dispatching plan. By comparing the calculation results of the... [more]
The Potential Antibacterial and Antifungal Activities of Wood Treated with Withania somnifera Fruit Extract, and the Phenolic, Caffeine, and Flavonoid Composition of the Extract According to HPLC
Mervat EL-Hefny, Mohamed Z. M. Salem, Said I. Behiry, Hayssam M. Ali
February 12, 2020 (v1)
Subject: Biosystems
Keywords: antimicrobial activity, flavonoid, phenolic, Withania somnifera fruits, wood bio-fungicide
In the present study, Melia azedarach wood blocks treated with different acetone extract concentrations from Withania somnifera fruits are assessed for their antibacterial and anti-fungal activities. Wood blocks of M. azedarach treated with W. somnifera fruit extract at concentrations of 0, 1, 2, and 3% are evaluated for in vitro antimicrobial activity against five genbank accessioned bacterial strains—Agrobacterium tumefaciens, Dickeya solani, Erwinia amylovora, Pseudomonas cichorii, and Serratia pylumthica—and two fungi, namely, Fusarium culmorum and Rhizoctonia solani. Through HPLC analysis we find that the most abundant quantified phenolic and flavonoid compounds of acetone extract (mg/100 g) are salicylic acid (9.49), vanillic acid (4.78), rutin (4702.58), and myricetin (1386.62). Wood treated with the extract at 2% and 3% show no growth of A. tumefaciens, E. amylovora, and P. cichorii. Use of the extract at 3% causes inhibition of fungal mycelia of F. culmorum and R. solani by 84... [more]
Evaluation of Different Treatment Processes for Landfill Leachate Using Low-Cost Agro-Industrial Materials
Tawfiq J. H. Banch, Marlia M. Hanafiah, Abbas F. M. Alkarkhi, Salem S. A. Amr, Nurul U. M. Nizam
February 12, 2020 (v1)
Keywords: coagulation, heavy metals, landfill, leachate treatment, removal efficiency, tannin
Leachate is a complex liquid that is often produced from landfills, and it contains hazardous substances that may endanger the surrounding environment if ineffectively treated. In this work, four leachate treatment applications were examined: combined leachate/palm oil mill effluent (POME) (LP), leachate/tannin (LT), pre-(leachate/tannin) followed by post-(leachate/POME) (LT/LP), and pre-(leachate/POME) followed by post-(leachate/tannin) (LP/LT). The aim of this work is to evaluate and compare the performance of these treatment applications in terms of optimizing the physicochemical parameters and removing heavy metals from the leachate. The highest efficiency for the optimization of the most targeted physicochemical parameters and the removal of heavy metals was with the LP/LT process. The results are indicative of three clusters. The first cluster involves raw leachate (cluster 1), the second contains LP and LP/LT (cluster 2), and the third also consists of two treatment applications... [more]
Co-Firing of Sawdust and Liquid Petroleum Gas in the Application of a Modified Rocket Stove
Paisan Comsawang, Suwat Nanetoe, Nitipong Soponpongpipat
February 12, 2020 (v1)
Keywords: co-firing, LPG stove, pyrolysis, rocket stove, sawdust
The heating rate, firepower, and thermal efficiency of a modified rocket stove using sawdust and liquid petroleum gas (LPG) as co-firing fuel were investigated. Three modified rocket stoves with a height of 400 mm and outside diameters of 225, 385, and 550 mm were tested. It was found that there was an insignificant difference in heating rate and firepower when stoves were tested without co-firing with LPG. In this case, the stove heating rate was in the range of 1.49−1.55 °C/min. When LPG was used, the heating rate tended to linearly increase with the increase of LPG flow rate. The heating rate was in range of 2.42−2.80, 2.63−3.27, and 3.07−4.22 °C/min when LPG consumption rates were 2.38 × 10−5, 3.33 × 10−5, and 5.00 × 10−5 kg/s, respectively. The slight increase of stove heating rate and firepower was seen when the stove diameter was increased from 225 to 385 mm. The increase of stove diameter from 385 to 550 mm resulted in a huge increase of heating rate and firepower. Thermal effi... [more]
Optimization Design and Analysis of Polymer High Efficiency Mixer in Offshore Oil Field
Zheng Shu, Shijie Zhu, Jian Zhang, Wensen Zhao, Zhongbin Ye
February 12, 2020 (v1)
Keywords: dissolving technique, Fluent, high-efficiency mixer, numerical simulation, polymer flooding
The degree of polymer-water mixing in high-pressure pipelines on offshore oilfields usually influences the polymer solution’s performance. To realize efficient mixing of the polymer mother liquor with dilution water in the high-pressure pipeline, a high-efficiency mixer is designed and optimized. The designed mixer consists of four parts: a T-shaped pipe as the main body, an inlet flow-splitting plate, a stainless-steel flow-guiding tube, and an outlet flow-splitting plate. Mathematical models are built by using computational fluid dynamics (CFD) and the mixing effects are compared by using Fluent. The research results show that compared with conventional T-shaped mixers, the designed high-efficiency mixer has better mixing performance and increases the mixing rate to 80%. To optimize the mixing rate, the length of the stainless-steel tube is increased and the tube is perforated to guide the flow. The result shows that boring holes along straight lines around the tube can achieve good... [more]
Short-Term Wind Power Prediction Based on Improved Grey Wolf Optimization Algorithm for Extreme Learning Machine
Jiale Ding, Guochu Chen, Kuo Yuan
February 12, 2020 (v1)
Keywords: extreme learning machine, improved grey wolf optimization algorithm, phase space reconstruction, variational mode decomposition
In order to improve the accuracy of wind power prediction and ensure the effective utilization of wind energy, a short-term wind power prediction model based on variational mode decomposition (VMD) and an extreme learning machine (ELM) optimized by an improved grey wolf optimization (GWO) algorithm is proposed. The original wind power sequence is decomposed into series of modal components with different center frequencies by the VMD method and some new sequences are obtained by phase space reconstruction (PSR). Then, the ELM model is established for different new time series, and the improved GWO algorithm is used to optimize its parameters. Finally, the output results are weighted and merged as the final predicted value of wind power. The root-mean-square error (RMSE), mean absolute error (MAE), and mean absolute percentage error (MAPE) of the proposed VMD-improved GWO-ELM prediction model in the paper are 5.9113%, 4.6219%, and 13.01% respectively, which are better than these of ELM,... [more]
Non-Linear Sliding Mode Controller for Photovoltaic Panels with Maximum Power Point Tracking
Hina Gohar Ali, Ramon Vilanova Arbos, Jorge Herrera, Andrés Tobón, Julián Peláez-Restrepo
February 12, 2020 (v1)
Keywords: integer order SMC, maximum power point tracking, perturb and observe algorithm, photovoltaic panel
In this paper, nonlinear sliding mode control (SMC) techniques formulated for extracting maximum power from a solar photovoltaic (PV) system under variable environmental conditions employing the perturb and observe (P and O) maximum power point tracking (MPPT) technique are discussed. The PV system is connected with load through the boost converter. A mathematical model of the boost converter is derived first, and based on the derived model, a SMC is formulated to control the gating pulses of the boost converter switch. The closed loop system stability is verified through the Lyapunov stability theorem. The presented control scheme along with the solar PV system is simulated in MATLAB (matric laboratory) (SMC controller and PWM (Pulse Width Modulation) part) and PSIM (Power electronics simulations) (solar PV and MPPT algorithm) environments using the Simcoupler tool. The simulation results of the proposed controller (SMC) are compared with the classical proportional integral derivative... [more]
Physicochemical Properties of Guava Snacks as Affected by Drying Technology
Yuri M. Leiton-Ramírez, Alfredo Ayala-Aponte, Claudia I. Ochoa-Martínez
February 12, 2020 (v1)
Subject: Materials
Keywords: convective drying, guava, lyophilization, properties, Refractance Window®
Guava is widely consumed because of its agro-industrial use, and its antioxidant properties attributed to vitamin C and carotenoids content. However, it has a short shelf life. Guava has been dried by atomization, fluidized bed, lyophilization (FD) and convective drying (CD). CD requires long operation times and the product characteristics are not desirable. In contrast, FD produces high quality products, but requires long processing times, high energy consumption and high operation costs. As an alternative, the Refractance Window® (RW) drying is relatively simple and cheap technique. The objective of this study was to compare the effect of CD, FD and RW techniques, on the moisture content, water activity, color, porosity, volume change, vitamin C and carotenoids content in guava samples. The samples dried by RW required less time to reduce the moisture content and exhibited smaller changes in color than CD or FD. There were greater losses of carotenoids and vitamin C when drying by CD... [more]
A Dynamic Active Safe Semi-Supervised Learning Framework for Fault Identification in Labeled Expensive Chemical Processes
Xuqing Jia, Wende Tian, Chuankun Li, Xia Yang, Zhongjun Luo, Hui Wang
February 12, 2020 (v1)
Keywords: active learning, chemical process, fault identification, feature selection, ontology, semi-supervised learning
A novel active semi-supervised learning framework using unlabeled data is proposed for fault identification in labeled expensive chemical processes. A principal component analysis (PCA) feature selection strategy is first given to calculate the weight of the variables. Secondly, the identification model is trained based on the obtained key process variables. Thirdly, the pseudo label confidence of identification model is dynamically optimized with an historical, current, and future pseudo label confidence mean. To increase the upper limit of the identification model that is self-learning with high entropy process data, active learning is used to identify process data and diagnosis fault causes by ontology. Finally, a PCA-dynamic active safe semi-supervised support vector machine (PCA-DAS4VM) for fault identification in labeled expensive chemical processes is built. The application in the Tennessee Eastman (TE) process shows that this hybrid technology is able to: (i) eliminate chemical... [more]
Ultrasonically Induced Sulfur-Doped Carbon Nitride/Cobalt Ferrite Nanocomposite for Efficient Sonocatalytic Removal of Organic Dyes
Surabhi Kamal, Guan-Ting Pan, Siewhui Chong, Thomas Chung-Kuang Yang
February 12, 2020 (v1)
Subject: Materials
Keywords: carbon nitride, catalyst, cobalt ferrite, nanocomposite, organic dye, SCN/CoFe2O4, sonocatalyst, ultrasound, ultrasound-assisted degradation
The sulfur-doped carbon nitride/cobalt ferrite nanocomposite (SCN/CoFe2O4) was prepared via ultrasonication and studied for the sonocatalytic degradation of wastewater organic dye pollutants including methylene blue, rhodamine B, and Congo red. The X-ray photoelectron spectroscopy confirmed the presence and atomic ratios of S, C, N, Co, Fe, and O elements and their corresponding bonds with Co2+ and Fe3+ cations. The nanocomposite was found to have aggregated nanoparticles on a sheet-like structure. The bandgap energy was estimated to be 1.85 eV. For the sonocatalytic degradation of 25-ppm methylene blue at 20 kHz, 1 W and 50% amplitude, the best operating condition was determined to be 1 g/L of catalyst dosage and 4 vol % of hydrogen peroxide loading. Under this condition, the sonocatalytic removal efficiency was the highest at 96% within a reaction period of 20 min. SCN/CoFe2O4 outperformed SCN and CoFe2O4 by 2.2 and 6.8 times, respectively. The SCN/CoFe2O4 nanocomposite was also foun... [more]
Hygro-Thermo-Mechanical Responses of Balsa Wood Core Sandwich Composite Beam Exposed to Fire
Luan TranVan, Vincent Legrand, Pascal Casari, Revathy Sankaran, Pau Loke Show, Aydin Berenjian, Chyi-How Lay
February 12, 2020 (v1)
Keywords: balsa core, buckling failure, mass loss kinetic, mechanical responses, moisture content, sandwich composite fire
In this study, the hygro−thermo−mechanical responses of balsa core sandwich structured composite was investigated by using experimental, analytical and numerical results. These investigations were performed on two types of specimen conditions: dry and moisture saturation sandwich composite specimens that are composed of E-glass/polyester skins bonded to a balsa core. The wet specimens were immersed in distilled water at 40 °C until saturated with water. The both dry and wet sandwich composite specimens were heated by fire. The mass loss kinetic and the mechanical properties were investigated by using a cone calorimeter following the ISO 5660 standard and three-point bending mechanical test device. Experimental data show that the permeability and fire resistance of the sandwich structure are controlled by two composite skins. Obtained results allow us to understand the Hygro−Thermo−Mechanical Responses of the sandwich structured composite under application conditions.
The Effects of Lung-Moistening Herbal Medicines on Bleomycin-Induced Pulmonary Fibrosis Mouse Model
Junmo Ahn, Hyejin Joo, Jihye Park, Jae-Woo Park, Kwan-Il Kim, Hee-Jae Jung, Youngmin Bu, Beom-Joon Lee
February 12, 2020 (v1)
Subject: Biosystems
Keywords: bleomycin, broncho alveolar lavage fluid, herbal medicine, inflammation, pulmonary fibrosis
In traditional medicine, lung-moistening herbal medicines (LMHM) are regarded as a major option for treating symptoms of pulmonary fibrosis (PF) including dry cough and dyspnea. As PF agents are being applied to the development of lung cancer agents, PF and lung cancer are reported to have high pathological and pharmacological relationships. This study was proposed to identify candidates for the treatment of PF via investigating the effect of LMHM on PF mouse model. PF was induced by intratracheal instillation of bleomycin. Six water extracts of LMHM such as Farfarae Flos (FAF), Trichosanthis Semen (TRS), Lilii Bulbus (LIB), Adenophorae Radix (ADR), Asteris Radix (ASR), and Scrophulariae Radix (SCR) were prepared and administered (300 mg/kg) orally for 10 days after induction. The changes in body weight, histopathology, and immune cell of bronchoalveolar lavage fluid (BALF) were investigated. Among those, LIB and ADR significantly decreased the deposition of collagen and septal thickne... [more]
Preparation of Sawdust-Filled Recycled-PET Composites via Solid-State Compounding
Rula M. Allaf, Esraa Albarahmieh, Mohammad Futian
February 12, 2020 (v1)
Subject: Materials
Keywords: cryomilling, film, PET, recycling, wood plastic composite
Recently, consumer markets have shown great interest in sustainable products. Considerable research efforts are headed towards developing biodegradable and recyclable polymers and composites. In this study, the fabrication of a wood−plastic composite (WPC) via solid state compounding has been examined. Polyethylene terephthalate (PET) and wood sawdust waste as major components of waste and challenging materials for the manufacturing of WPCs have been explored. Furthermore, the addition of poly(ε-caprolactone) as a biodegradable plasticizing agent was investigated. Composite powders were prepared by cryogenic solid-state milling (cryomilling) according to a statistical mixture design. Mechanical and water absorption properties were inspected on film samples obtained by hot pressing. Different formulations resulted in a variety of colors, textures, water interactions and mechanical properties. A sawdust content of approximately 25 vol.% was optimal for the best combination of properties.... [more]
Assessment of the Usefulness of the Twin-Screw Press in Terms of the Pressing Efficiency and Antioxidant Properties of Apple Juice
Kamil Wilczyński, Zbigniew Kobus, Rafał Nadulski, Marek Szmigielski
February 12, 2020 (v1)
Subject: Other
Keywords: antioxidant activity, ascorbic acid, hardness, mechanical properties, polyphenols, texture, twin-screw press
The paper presents the possibility of applying a twin-screw press for juice extraction from apples with different textural properties. The research was carried out with six different varieties; namely, Granny Smith, Modi, Ligol, Lobo, Boscop and Szampion. During the experiment, the following properties were measured: texture properties, pressing yield and polyphenolic content; and ascorbic acid content and antioxidant activity both in raw apples and apple juice. Based on the analysis, three hardness levels of apples can be distinguished, impacting the course of juice pressing in a twin-screw press (low hardness below 30 N, medium hardness 30−50 N and high hardness 50 N). The study showed that only high hardness apples are suitable for pressing on a twin-screw press. The mechanism by which texture properties influence the juice pressing process in the studied press was explained. It was further demonstrated that the hardness of apples has a positive impact on the degree of extraction of... [more]
Acid-Base Flow Battery, Based on Reverse Electrodialysis with Bi-Polar Membranes: Stack Experiments
Jiabing Xia, Gerhart Eigenberger, Heinrich Strathmann, Ulrich Nieken
February 12, 2020 (v1)
Keywords: acid-base neutralization flow battery, electrical energy storage, reverse electrodialysis with bipolar membranes, stack test results
Neutralization of acid and base to produce electricity in the process of reverse electrodialysis with bipolar membranes (REDBP) presents an interesting but until now fairly overlooked flow battery concept. Previously, we presented single-cell experiments, which explain the principle and discuss the potential of this process. In this contribution, we discuss experiments with REDBP stacks at lab scale, consisting of 5 to 20 repeating cell units. They demonstrate that the single-cell results can be extrapolated to respective stacks, although additional losses have to be considered. As in other flow battery stacks, losses by shunt currents through the parallel electrolyte feed/exit lines increases with the number of connected cell units, whereas the relative importance of electrode losses decreases with increasing cell number. Experimental results are presented with 1 mole L−1 acid (HCl) and base (NaOH) for open circuit as well as for charge and discharge with up to 18 mA/cm2 current densi... [more]
Influence of Eccentricity on Hydrodynamic Characteristics of Nuclear Reactor Coolant Pump under Different Cavitation Conditions
Yuanyuan Zhao, Bin Lin, Xiuli Wang, Rongsheng Zhu, Qiang Fu
February 12, 2020 (v1)
Keywords: axial force, cavitation, eccentricity, nuclear reactor coolant pump, radial force
In order to study the influence of eccentricity on hydrodynamic characteristics of nuclear reactor coolant pump under different cavitation conditions, five different schemes were obtained by analyzing and optimizing the existing structural schemes. Based on the RNG k-ε model (Renormalization Group with k-epsilon turbulence models) and two-fluid two-phase flow model, the unsteady numerical analysis and test verification of different designed schemes are carried out by using the flow field software ANSYS CFX. The results of research show that different eccentricities will affect the nuclear reactor coolant pump’s head under different cavitation conditions, and the corresponding head in the scheme with the eccentricity of 5mm under the fracture cavitation condition is lower than that of the other schemes. When the impeller rotates at a certain angle from the initial position under critical and severe cavitation conditions, the radial force acting on the rotor system will fluctuate greatly... [more]
Hierarchical Cs−Pollucite Nanozeolite Modified with Novel Organosilane as an Excellent Solid Base Catalyst for Claisen−Schmidt Condensation of Benzaldehyde and Acetophenone
Aleid Ghadah Mohammad S., Fitri Khoerunnisa, Severinne Rigolet, T. Jean Daou, Tau-Chuan Ling, Eng-Poh Ng
February 12, 2020 (v1)
Keywords: Claisen–Schmidt condensation, Cs–pollucite, hierarchical structure, nanozeolite, non-microwave instant heating, organosilane porogen
Cs−pollucite can be a potential solid base catalyst due to the presence of (Si-O-Al)−Cs+ basic sites. However, it severely suffers from molecular diffusion and pore accessibility problems due to its small micropore opening. Herein, we report the use of new organosilane, viz. dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride (TPOAC), as a promising pore-expanding agent to develop the hierarchical structure in nanosized Cs−pollucite. In respect to this, four different amounts of TPOAC were added during the synthesis of hierarchical Cs−pollucite (CP-x, x = 0, 0.3, 1.0, or 2.0, where x is the molar ratio of TPOAC) in order to investigate the effects of TPOAC in the crystallization process of Cs−pollucite. The results show that an addition of TPOAC altered the physico-chemical and morphological properties of hierarchical Cs−pollucite, such as the crystallinity, crystallite size, pore size distribution, surface areas, pore volume, and surface basicity. The prepared solids were al... [more]
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