Records Added in March 2021
Records added in March 2021
Change year: 2018 | 2019 | 2020 | 2021 | 2022 | 2023
Change month: January | February | March | April | May | June | July | August | September | October | November | December
Showing records 45 to 69 of 69. [First] Page: 1 2 3 Last
Mitigation of Chromium Poisoning of Ferritic Interconnect from Annealed Spinel of CuFe2O4
Muhammad Aqib Hassan, Othman Bin Mamat
March 14, 2021 (v1)
Subject: Materials
Keywords: coating, copper-ferrous oxide, Crofer 22 APU, metallic interconnect, Solid Oxide Fuel Cell, SUS 430
Low-temperature solid oxide fuel cells permit the possibility of metallic interconnects over conventional ceramic interconnects. Among various metallic interconnects, the ferritic interconnects are the most promising. However, chromium poisoning in them adversely affects their performance. To resolve this issue, various coatings and pretreatment methods have been studied. Herein, this article encloses the coating of CuFe2O4 spinel over two prominent ferritic interconnects (Crofer 22 APU and SUS 430). The CuFe2O4 spinel layer coating has been developed by the dip-coating of both samples in CuFe2O4 slurry, followed by heat treatment at 800 °C in a reducing environment (5% hydrogen and 95% nitrogen). Additionally, both samples were annealed to further enhance their spinel coating structure. The morphological and crystallinity analysis confirmed that the spinel coating formed multiple layers of protection while annealing further reduced the thickness and improved the densities. Moreover, t... [more]
Life Cycle Assessment and Economic Analysis of Biomass Energy Technology in China: A Brief Review
Shuangyin Chen, He Feng, Jun Zheng, Jianguo Ye, Yi Song, Haiping Yang, Ming Zhou
March 14, 2021 (v1)
Subject: Energy Policy
Keywords: biomass power generation, economic evaluation, environment load, life cycle assessment
This study describes the technological processes and characteristics of biomass direct combustion power generation, biomass gasification power generation, biomass mixed combustion power generation, and biomass biogas power generation in terms of their importance and application in China. Under the perspective of environmental and economic sustainability, the life cycle assessment (LCA) method and dynamic analysis method based on time value are used to simulate and evaluate the environmental loads and economic benefits of different power generation processes. By comparing with coal-fired power generation systems, the environmental and economic benefits of different biomass power generation technologies are illustrated. The results shows that biomass gasification power generation has the best environmental benefits, with a total load of 1.05 × 10−5, followed by biomass biogas power generation (9.21 × 10−5), biomass direct combustion power generation (1.23 × 10−4), and biomass mixed combu... [more]
Coal-Degrading Bacteria Display Characteristics Typical of Plant Growth Promoting Rhizobacteria
Yinka Titilawo, Wiya L. Masudi, Jacob T. Olawale, Lerato M. Sekhohola-Dlamini, A. Keith Cowan
March 14, 2021 (v1)
Subject: Biosystems
Keywords: biodegradation, coal discard, diesel-contaminated soil, discard dumps, phylogeny, plant growth-promoting bacteria
Coal mining produces large quantities of discard that is stockpiled in large dumps. This stockpiled material, termed coal discard, poses an environmental threat emphasising the need for appropriate bioremediation. Here, metagenomic analysis of the 16S rRNA from ten coal-degrading strains previously isolated from coal slurry from discard dumps and from the rhizosphere of diesel-contaminated sites was used to establish genetic relatedness to known plant growth-promoting (PGP) bacteria in the NCBI database. Measurement of indole and ammonium production and solubilisation of P and K were used to screen bacteria for PGP characteristics. BLAST analysis revealed ≥ 99% homology of six isolates with reference PGP strains of Bacillus, Escherichia, Citrobacter, Serratia, Exiguobacterium and Microbacterium, while two strains showed 94% and 91% homology with Proteus. The most competent PGP strains were Proteus strain ECCN 20b, Proteus strain ECCN 23b and Serratia strain ECCN 24b isolated from diese... [more]
Development, Characterization and In Vitro Evaluation of Paclitaxel and Anastrozole Co-Loaded Liposome
Minh Thanh Vu, Dinh Tien Dung Nguyen, Ngoc Hoi Nguyen, Van Thu Le, The Nam Dao, Thi Huong Nguyen, Tien Dung Cong, Truc Le-Buu Pham, Tri Duc Lam, Ngoc Thuy Trang Le
March 14, 2021 (v1)
Subject: Biosystems
Keywords: anastrozole, co-loaded, drug delivery system, paclitaxel, soy lecithin liposome
Paclitaxel (PTX) and anastrozole (ANA) have been frequently applied in breast cancer treatment. PTX is well-known for its anti-proliferative effect meanwhile ANA has just been discovered to act as an estrogen receptor α (ERα) ligand. The combination therapy of PTX and ANA is expected to improve treating efficiency, as ANA would act as a ligand binding with the ERα gene expressed in breast cancer cells and thereafter PTX would inhibit the division and cause death to those cancer cells. In this study, liposome-based nanocarriers (LP) were developed for co-encapsulation of PTX and ANA to improve the efficacy of the combined drugs in an Estrogen receptor-responsive breast cancer study. PTX-ANA co-loaded LP was prepared using thin lipid film hydration method and was characterized for morphology, size, zeta potential, drug encapsulation and in vitro drug release. In addition, cell proliferation (WST assay) and IN Cell Analyzer were used for in vitro cytotoxicity studies on a human breast can... [more]
Influence of Aerobic Pretreatment of Poultry Manure on the Biogas Production Process
Mantas Rubežius, Kęstutis Venslauskas, Kęstutis Navickas, Rolandas Bleizgys
March 14, 2021 (v1)
Keywords: aerobic pretreatment, ammonia mitigation, anaerobic digestion, poultry manure management
Anaerobic digestion of poultry manure is a potentially-sustainable means of stabilizing this waste while generating biogas. However, technical, and environmental protection challenges remain, including high concentrations of ammonia, low C/N ratios, limited digestibility of bedding, and questions about transformation of nutrients during digestion. This study evaluated the effect of primary biological treatment of poultry manure on the biogas production process and reduction of ammonia emissions. Biogas yield from organic matter content in the aerobic pretreatment groups was 13.96% higher than that of the control group. Biogas production analysis showed that aerobic pretreatment of poultry manure has a positive effect on biogas composition; methane concentration increases by 6.94−7.97% after pretreatment. In comparison with the control group, NH3 emissions after aerobic pretreatment decreased from 3.37% (aerobic pretreatment without biological additives) to 33.89% (aerobic pretreatment... [more]
Aspen Plus Simulation of a Rectisol Process for Blue Hydrogen Production
Thomas A Adams II
March 12, 2021 (v2)
This is an Aspen Plus v12 model for a Rectisol process used for removing CO2 from a shifted syngas stream arising from steam methane reforming for the purposes of Blue hydrogen production. It is intended for educational use, and is useful as a starting point for those interested in simulating this process. It is not optimized in any way, but it contains a working flowsheet for those interested in modifying it for your own purposes.

The simulation was developed using the simulation strategy given in Adams TA II, Khojestah Salkuyeh Y, Nease J. Processes and Simulations for Solvent-based CO2Capture and Syngas Cleanup. Chapter in: Reactor and process design for in sustainable energy technology. Elsevier (2014). Pages 163-232. ISBN: 978-0-444-59566-9. It is based on the process discussed in Doctor RD, Molburg JC, Thimmapuram PR, Berry GF, Livengood CD. Gasification combined cycle: carbon dioxide recovery, transport, and disposal. US DOE Report, Argonne National Laboratory ANL/ESD-24. 19... [more]
Optimal design and operation of a waste tire feedstock polygeneration system
Avinash Shankar Rammohan Subramanian, Truls Gundersen, Thomas A. Adams II
October 8, 2020 (v1)
Keywords: Carbon Dioxide Capture, Gasification, Global Optimization, Polygeneration system, Rubber, Waste Tire, Waste-to-Energy
The accompanying model for the paper 'Optimal design and operation of a waste tire feedstock polygeneration system' is presented. The model is written using the GOSSIP software platform and modeling language.
Melt Stable Functionalized Organosolv and Kraft Lignin Thermoplastic
Shubhankar Bhattacharyya, Leonidas Matsakas, Ulrika Rova, Paul Christakopoulos
March 1, 2021 (v1)
Subject: Materials
Keywords: etherification, Kraft lignin, lignin, lignin functionalization, organosolv, thermoplastics
A shift towards an economically viable biomass biorefinery concept requires the use of all biomass fractions (cellulose, hemicellulose, and lignin) for the production of high added-value products. As lignin is often underutilized, the establishment of lignin valorization routes is highly important. In-house produced organosolv as well as commercial Kraft lignin were used in this study. The aim of the current work was to make a comparative study of thermoplastic biomaterials from two different types of lignins. Native lignins were alkylate with two different alkyl iodides to produce ether-functionalized lignins. Successful etherification was verified by FT-IR spectroscopy, changes in the molecular weight of lignin, as well as 13C and 1H Nuclear Magnetic Resonance (NMR). The thermal stability of etherified lignin samples was considerably improved with the T2% of organosolv to increase from 143 °C to up to 213 °C and of Kraft lignin from 133 °C to up to 168 °C, and glass transition temper... [more]
Simulation Data of Regional Economic Analysis of OTEC for Applicable Area
Lim Seungtaek, Lee Hosaeng, Moon Junghyun, Kim Hyeonju
March 1, 2021 (v1)
Subject: Energy Policy
Keywords: closed cycle, internal rate of return, net present value, ocean thermal energy conversion, open cycle
To mitigate the power shortage problem in the South Pacific island nations and the equatorial area, we studied the development characteristics of ocean thermal energy conversion (OTEC) using abundant clean ocean energy. Through the simulation of open- and closed-cycle OTEC, the generation amount and its economic efficiency were compared, and the application characteristics of the power generation cycle according to the seawater temperature distribution were compared by applying various seawater temperature conditions. According to the characteristics of seawater heat sources in the region, the power generation output was about 883.2 kW in Samoa, and the average power generation by region was about 650.5 kW for the open-cycle OTEC model. Regional revenue up to approximately $8,487,000 was generated in Kiribati, driven by the higher electricity tariff of $0.327/kWh and high water costs of $5.86/ton. With the spread of 50 MW commercial plants, Kiribati had a high net present value of $1,9... [more]
Improving the Energy Efficiency of Industrial Refrigeration Systems by Means of Data-Driven Load Management
Josep Cirera, Jesus A. Carino, Daniel Zurita, Juan A. Ortega
March 1, 2021 (v1)
Keywords: Compressors, data-driven, energy disaggregation, Energy Efficiency, load management, multi-layer perceptron, NILM, Optimization, partial load ratio, refrigeration systems
A common denominator in the vast majority of processes in the food industry is refrigeration. Such systems guarantee the quality and the requisites of the final product at the expense of high amounts of energy. In this regard, the new Industry 4.0 framework provides the required data to develop new data-based methodologies to reduce such energy expenditure concern. Focusing in this issue, this paper proposes a data-driven methodology which improves the efficiency of the refrigeration systems acting on the load side. The solution approaches the problem with a novel load management methodology that considers the estimation of the individual load consumption and the necessary robustness to be applicable in highly variable industrial environments. Thus, the refrigeration system efficiency can be enhanced while maintaining the product in the desired conditions. The experimental results of the methodology demonstrate the ability to reduce the electrical consumption of the compressors by 17%... [more]
Calculating the Binary Tortuosity in DEM-Generated Granular Beds
Wojciech Sobieski
March 1, 2021 (v1)
Keywords: A-Star Algorithm, binary tortuosity, Discrete Element Method, granular beds, Path Searching Algorithm, porous media
In this paper, a methodology of calculating the tortuosity in three-dimensional granular beds saved in a form of binary geometry with the application of the A-Star Algorithm and the Path Searching Algorithm is presented. The virtual beds serving as examples are prepared with the use of the Discrete Element Method based on data of real, existing samples. The obtained results are compared with the results described in other papers (obtained by the use of the Lattice Boltzmann Method and the Path Tracking Method) as well as with the selected empirical formulas found in the literature. It was stated in the paper that the A-Star Algorithm gives values similar (but always slightly underestimated) to the values obtained via approaches based on the Lattice Boltzmann Method or the Path Tracking Method. In turn, the Path Searching Algorithm gives results in the same value range as popular empirical formulas and additionally it is approximately two times faster than the A-Star Algorithm.
Technical Route to Achieve Ultra-Low Emission of Nitrogen Oxides with Predictive Model of Nitrogen Oxide Background Concentration
Yanfei Yao, Yanxin Chen
March 1, 2021 (v1)
Subject: Other
Keywords: nitrogen oxide, Pearson coefficient, soft sensor, ultra-low emission
As the most mature denitration technology in the cement clinker burning process, selective non-catalytic reduction (SNCR) has been unable to meet the requirements of ultra-low nitrogen oxide (NOX) emissions under low ammonia escape, thus a hybrid denitration process based on SNCR was established. The process had three steps: reducing the NOX background concentration (NBC), implementing staged combustion, and optimizing the effect of the SNCR. One of the keys to this process was the real-time acquisition of the NBC. In this paper, a multivariate linear regression model for the prediction of NBC was constructed and applied to one 12,000 t/d production line and one 5000 t/d production line. For the 12,000 t/d production line, NBC had a positive correlation with the temperature of the calciner outlet, the pressure, and the temperature of the kiln hood, and it had a negative correlation with the quantity of the kiln coal, the temperature of the smoke chamber, and the main motor current of t... [more]
Numerical Study on the Influence of Step Casing on Cavitating Flows and Instabilities in Inducers with Equal and Varying Pitches
Lu Yu, Haochen Zhang, Hui Chen, Zhigang Zuo, Shuhong Liu
March 1, 2021 (v1)
Keywords: cavitating flow and instabilities, inducer, step casing, varying pitch
It is known that cavitating flow characteristics and instabilities in inducers can greatly impact the safety and stability of a liquid rocket. In this paper, step casing optimization design (Model OE and Model AE) was carried out for two three-bladed inducers with an equal (Model O) and a varying pitch (Model A), respectively. The unsteady cavitation flow field and accompanied instabilities were studied via numerical simulations. Reductions of the cavity size and fluctuation were observed in cases with a step casing. A significant difference in cavity structures was seen as well. Referring to the pressure distributions on the blades and details of the flow field, the mechanism of cavitation suppression was revealed. This work provides a feasible and convenient method in engineering practice for optimizing the characteristic of the cavitating flow field and instabilities for the inducer.
MILP Formulation for Solving and Initializing MINLP Problems Applied to Retrofit and Synthesis of Hydrogen Networks
Patrícia R. da Silva, Marcelo E. Aragão, Jorge O. Trierweiler, Luciane F. Trierweiler
March 1, 2021 (v1)
Subject: Optimization
Keywords: hydrogen network, initialization strategy, mathematical programming, MILP optimization, MINLP optimization, virtual compressor approach
The demand for hydrogen in refineries is growing due to its importance as a sulfur capture element. Therefore, hydrogen management is critical for fulfilling demands as efficiently as possible. Through mathematical modeling, hydrogen network management can be better performed. Cost-efficient Mixed-Integer Linear Programming (MILP) and Mixed-Integer Nonlinear Programming (MINLP) optimization models for (re)designing were proposed and implemented in GAMS with two case studies. Linear programming has the limitation of no stream mixing allowed; therefore, to overcome this limitation, an algorithm-based procedure called the Virtual Compressor Approach was proposed. Based on the MILP optimal solution obtained, the streams and compressors were merged. As a result, the number of compressors was reduced, along with the inherent investment costs. An operational cost reduction of more than 28% (example 1) and 26% (example 2) was obtained with a linear model. The optimal MILP solution after rearra... [more]
Large Eddy Simulations of Reactive Mixing in Jet Reactors of Varied Geometry and Size
Krzysztof Wojtas, Wojciech Orciuch, Łukasz Makowski
March 1, 2021 (v1)
Keywords: Computational Fluid Dynamics, confined impinging jet reactors, large eddy simulation, Mixing, parallel chemical reactions
We applied large eddy simulation (LES) to predict the course of reactive mixing carried out in confined impinging jet reactors (CIJR). The reactive mixing process was studied in a wide range of flow rates both experimentally and numerically using computational fluid dynamics (CFD). We compared several different reactor geometries made in different sizes in terms of both reaction yields and mixing efficiency. Our LES model predictions were validated using experimental data for the tracer concentration distribution and fast parallel chemical test reactions, and compared with the k-ε model supplemented with the turbulent mixer model. We found that the mixing efficiency was not affected by the flow rate only at the highest tested Reynolds numbers. The experimental results and LES predictions were found to be in good agreement for all reactor geometries and operating conditions, while the k-ε model well predicted the trend of changes. The CFD method used, i.e., the modeling approach using c... [more]
Fault Detection and Isolation System Based on Structural Analysis of an Industrial Seawater Reverse Osmosis Desalination Plant
Gustavo Pérez-Zuñiga, Raul Rivas-Perez, Javier Sotomayor-Moriano, Victor Sánchez-Zurita
March 1, 2021 (v1)
Keywords: diagnostic test, model based fault diagnosis, seawater reverse osmosis desalination plant, structural analysis, water scarcity
Currently, the use of industrial seawater reverse osmosis desalination (ISROD) plants has increased in popularity in light of the growing global demand for freshwater. In ISROD plants, any fault in the components of their control systems can lead to a plant malfunction, and this condition can originate safety risks, energy waste, as well as affect the quality of freshwater. This paper addresses the design of a fault detection and isolation (FDI) system based on a structural analysis approach for an ISROD plant located in Lima (Peru). Structural analysis allows obtaining a plant model, which is useful to generate diagnostic tests. Here, diagnostic tests via fault-driven minimal structurally overdetermined (FMSO) sets are computed, and then, binary integer linear programming (BILP) is used to select the FMSO sets that guarantee isolation. Simulations shows that all the faults of interest (sensors and actuators faults) are detected and isolated according to the proposed design.
The Effect of Citric Acid, NaCl, and CaCl2 on Qualitative Changes of Horse Meat in Cold Storage
Renata Stanisławczyk, Mariusz Rudy, Marian Gil, Paulina Duma-Kocan, Dariusz Dziki, Stanisław Rudy
March 1, 2021 (v1)
Keywords: citric acid, horse meat quality, marinating, physicochemical properties, sensory analysis, sodium chloride
In this study, we aimed to analyze the effect of citric acid, NaCl, and CaCl2 on the qualitative changes of horse meat during cold storage. The study material was the longest dorsal muscles (M. longissimus dorsi (LM)) obtained from twelve half-carcasses of horses. The muscle was cut into five steaks, each of which was about 3 cm thick. One sample was kept as a control sample, and the remaining ones were treated with NaCl, citric acid, and CaCl2 (0.2 M and 0.3 M). The study material was obtained 24 h after the slaughter of the animals and was marinated in solution (citric acid and 0.2 M and 0.3 M calcium chloride) and by sprinkling and rubbing (sodium chloride). The applied treatments significantly (p ≤ 0.05) improved the texture parameters of horse meat (univariate analysis of variance). Citric acid caused deterioration of the study material with respect to the binding and retention of intrinsic water. Among the tested material, the lightest color of the meat was obtained for sample ma... [more]
Bubble Properties in Bubbling and Turbulent Fluidized Beds for Particles of Geldart’s Group B
Tom Wytrwat, Mahdi Yazdanpanah, Stefan Heinrich
March 1, 2021 (v1)
Subject: Other
Keywords: bubble size, bubble velocity, bubbling, capacitance probe, fluidized bed, Geldart group B, phase holdup, regime transition, turbulent
Predicting bubble properties in fluidized beds is of high interest for reactor design and modeling. While bubble sizes and velocities for low velocity bubbling fluidized beds have been examined in several studies, there have been only few studies about bubble behavior at superficial gas velocities up into the turbulent regime. For this reason, we performed a thorough investigation of the size, shape and velocity of bubbles at superficial gas velocities ranging from 0.18 m/s up to 1.6 m/s. Capacitance probes were used for the determination of the bubble properties in three different fluidized bed facilities sized of 0.1 m, 0.4 m and 1 m in diameter. Particles belonging to Geldart’s group B (Sauter mean diameter: 188 µm, solid density: ρs = 2600 kg/m3) were used. Correlations for the determination of bubble phase holdup, vertical bubble length and bubble velocity are introduced in this work. The shape of bubbles was found to depend on superficial gas velocity. This implies that at large... [more]
Non-Antagonistic Contradictoriness of the Progress of Advanced Digitized Production with SARS-CoV-2 Virus Transmission in the Area of Dental Engineering
Leszek A. Dobrzański, Lech B. Dobrzański, Anna D. Dobrzańska-Danikiewicz, Joanna Dobrzańska, Karolina Rudziarczyk, Anna Achtelik-Franczak
March 1, 2021 (v1)
Subject: Other
Keywords: additive digital light printing, dendrological matrix, dentistry 4.0, elimination clinical aerosol at the source, Industry 4.0, photopolymer materials, SARS-CoV-2 pandemic, SPEC strategy
The general goals of advanced digitized production in the Industry 4.0 stage of the industrial revolution were presented along with the extended holistic model of Industry 4.0, introduced by the authors, indicating the importance of material design and the selection of appropriate manufacturing technology. The effect of the global lockdown caused by the SARS-CoV-2 virus transmission pandemic was a drastic decrease in production, resulting in a significant decrease in the gross domestic product GDP in all countries, and gigantic problems in health care, including dentistry. Dentists belong to the highest risk group because the doctor works in the patient’s respiratory tract. This paper presents a breakthrough authors solution, implemented by the active SPEC strategy, and aims to eliminate clinical aerosol at the source by negative pressure aspirating bioaerosol at the patient’s mouth line. The comparative benchmarking analysis and its results show that only the proprietary solution with... [more]
Research on Optimal Control of Excavator Negative Control Swing System
Lijie Zhang, Wenbo Fu, Xiaoming Yuan, Zhaoliang Meng
March 1, 2021 (v1)
Keywords: braking stability, excavator swing system, main valve pilot pressure, overflow, PRV, response
In order to improve the energy efficiency and dynamic of negative control swing systems of excavators, this paper proposes a technical scheme of adding two PRVs (pressure reducing valves) to main valve pilot control circuit, which can adjust main value opening arbitrarily according to the working condition. A pump-value compound control strategy was formulated to regulate the system power flow. During swing motor acceleration, main pump and the two PRVs are controlled to match system supply flow with motor demand flow, thereby reducing motor overflow and shortening system response time. During swing motor braking, the channel from motor to tank is opened to release hydraulic brake pressure by controlling PRVs before swing speed reduces to zero, which prevents the motor from reversing and oscillating. A simulation model of 37-ton excavator was established, and the control strategy was simulated. The original and optimized performance of the swing system were compared and analyzed, and r... [more]
Development of an Oxygen Pressure Estimator Using the Immersion and Invariance Method for a Particular PEMFC System
Ángel Hernández-Gómez, Victor Ramirez, Belem Saldivar
March 1, 2021 (v1)
Keywords: estimator development, Lyapunov’s Theorem application, non-linear system, PEMFC system, sensor replacement
The fault detection method has been used usually to give a diagnosis of the performance and efficiency in the proton exchange membrane fuel cell (PEMFC) systems. To be able to use this method a lot of sensors are implemented in the PEMFC to measure different parameters like pressure, temperature, voltage, and electrical current. However, despite the high reliability of the sensors, they can fail or give erroneous measurements. To address this problem, an efficient solution to replace the sensors must be found. For this reason, in this work, the immersion and invariance method is proposed to develop an oxygen pressure estimator based on the voltage, electrical current density, and temperature measurements. The estimator stability region is calculated by applying Lyapunov’s Theorem and constraints to achieve stability are established for the oxygen pressure, electrical current density, and temperature. Under these estimator requirements, oxygen pressure measurements of high reliability a... [more]
Effect of Mixed Commercial Cold Flow Improvers on Flow Properties of Biodiesel from Waste Cooking Oil
Siyu Nie, Leichang Cao
March 1, 2021 (v1)
Keywords: biodiesel, mechanism, mixed cold flow improver, orthogonal experiment
The uniform design method was used to screen the solidifying point depressing effects of 18 traditional diesel cold flow improvers on biodiesel derived from waste cooking oil. The cold flow improvers with good effects were selected for orthogonal optimization. Finally, the mixed cold flow improver (CFI) with the best depressing effect was selected to explore its depressing mechanism for biodiesel. The results show that the typical CFIs such as A132, A146, 10-320, 10-330, A-4, CS-1, AH-BSFH, Haote, T1804D, and HL21 all have a certain solidifying point depressing effect on biodiesel, while other cold flow improvers had no obvious effect. Amongst them, 10-330 (PMA polymer) and AH-BSFH (EVA polymer) had better solidifying point depressing effects over others, both of which reduced the solidifying point (SP) of biodiesel by 4 °C and the cold filter plugging point (CFPP) by 2 °C and 3 °C, respectively. From the orthogonal mixing experiment, it can be seen that the combination of 10-330 and A... [more]
Short-Chain Polyglycerol Production via Microwave-Assisted Solventless Glycerol Polymerization Process Over Lioh-Modified Aluminium Pillared Clay Catalyst: Parametric Study
Muhammad Sajid, Muhammad Ayoub, Suzana Yusup, Bawadi Abdullah, Rashid Shamsuddin, Roil Bilad, Chi Cheng Chong, Aqsha Aqsha
March 1, 2021 (v1)
Keywords: alkali modified, aluminium pillared clay, glycerol polymerization, microwave, polyglycerol
In the current study, microwave-assisted glycerol polymerization for short-chain polyglycerol production was conducted unprecedentedly over low-cost catalyst, lithium-modified aluminium pillared clay (Li/AlPC) catalysts without the solvent. The influences of disparate reaction parameters such as the effects of Li loadings (10, 20, 30 wt.%), catalyst loadings (2, 3, 4 wt.%), operating temperatures (200, 220, 240 °C) and operating times (1−4 h) on the glycerol conversions, and polyglycerol yield (particularly for diglycerol and triglycerol), were elucidated. The fresh catalysts were subjected to physicochemical properties evaluation via characterization techniques, viz. N2 physisorption, XRD, SEM, NH3-TPD and CO2-TPD. In comparison, 20 wt.% Li/AlPC demonstrated the best performance under non-conventional heating, credited to its outstanding textural properties (an increase of basal spacing to 21 Ȧ, high surface area of 95.48 m2/g, total basicity of 34.48 mmol/g and average pore diameter... [more]
Scale-Up of Self-Regenerating Semi-Batch Adsorption Cycles through Concurrent Adsorption and Reduction of Cr(VI) on Sheep Wool
Mohamed Badrelzaman, Mustafa I. Khamis, Taleb H. Ibrahim, Fawwaz H. Jumean
March 1, 2021 (v1)
Keywords: Adsorption, hexavalent chromium, industrial wastewater, semi-batch adsorption cycles, wool
A previous publication by our group reported that adsorption of Cr(VI) on sheep wool reached 99% when allowed a long residence time, with concurrent reduction to Cr(III). In this study, the process was scaled up by optimizing a pilot plant based on semi-batch adsorption cycles. This yielded Cr(III), which is about 300 times less toxic than Cr(VI), and can be precipitated using lime at high pH. Since the reduction step is slower than the adsorption one, an adsorption column was designed to perform semi-batch operation cycles, whereby the extended “off cycle” allows reduction to take place. Since reduction of Cr(VI) frees active sites on wool, the plant acts in lieu of in situ regeneration, accompanied by additional adsorption of Cr(VI). The results show that 97% of the column efficiency can be recovered within 24 h of “off cycle”. Wastewater from a local electroplating industry was treated by this method with high removal of Cr(VI), reaching the limit permitted by environmental standard... [more]
Freeze-Drying with Structured Sublimation Fronts—Visualization with Neutron Imaging
Nicole Vorhauer-Huget, David Mannes, Mathias Hilmer, Sebastian Gruber, Markus Strobl, Evangelos Tsotsas, Petra Foerst
March 1, 2021 (v1)
Subject: Other
Keywords: drying front, freeze-drying, front structure, image analysis, neutron tomography
The particular structure of the sublimation front in vacuum freeze-drying of porous media is, in most situations, not accessible at the pore scale. The classical measurement techniques access the process only globally. Knowledge about the structure of the front, however, is necessary for prescriptive analysis of freeze-drying, as it dictates not only drying velocity, drying time, and overall energy consumption, but also the material properties after drying. This is especially relevant in situations in which the freeze-drying process is carried out close to the collapse temperature of the product. We, therefore, study the sublimation of ice with neutron tomography and analyze the spatial formation of the dry space using the example of frozen cylindrical maltodextrin with drying parameters at the limit of material collapse. We show that the sublimation front forms unique fractal structures that differ strongly from the usual form of a flat front. Distinct dry fingers covering the sample,... [more]
Showing records 45 to 69 of 69. [First] Page: 1 2 3 Last
Change year: 2018 | 2019 | 2020 | 2021 | 2022 | 2023
Change month: January | February | March | April | May | June | July | August | September | October | November | December