Records Added in March 2021
Records added in March 2021
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Showing records 1 to 25 of 69. [First] Page: 1 2 3 Last
Condensation Heat Transfer of R-407C in Helical Coiled Tube Heat Exchanger
Hamad Mohammad AlHajeri, Abdulrahman Almutairi, Mohamad Hamad Al-Hajeri, Abdulrahman Alenezi, Rashed ALajmi, Aboelyazeid Mohamed Koluib
March 24, 2021 (v1)
Subject: Materials
Keywords: condensation, heat transfer, helical tube, R-407C
The results of an experimental study to evaluate the characteristics of R-407C thermofluid during condensation in a helically coiled copper tube heat exchanger are presented. The effects of saturation temperature (Tsat), and mass and heat fluxes of refrigerant R-407C on thermal performance and pressure drop were determined. The relationship between the refrigerant wall subcooling and heat transfer coefficients was also investigated. This paper reports the effect of the temperature of the water used as cooling medium on the heat transfer rate of condensing R-407C. The study was conducted with mass flux of R-407C in the range of 100−450 kg/m2s, mass flux of the coolant water in the range of 500−5000 kg/m2s and Tsat of 31 °C, 35 °C, and 39 °C. Compared with a straight smooth tube, the use of the helical coiled (helicoidal) tube increased the condensation rate with a corresponding pressure drop that depended on the value of Tsat of the refrigerant and temperature of the coolant.
On the Application of the FactSage Thermochemical Software and Databases in Materials Science and Pyrometallurgy
Jean-Philippe Harvey, Francis Lebreux-Desilets, Jeanne Marchand, Kentaro Oishi, Anya-Fettouma Bouarab, Christian Robelin, Aimen E. Gheribi, Arthur D. Pelton
March 24, 2021 (v1)
Subject: Materials
Keywords: computational thermochemistry, FactSage, process simulation
The discovery of new metallic materials is of prime importance for the development of new technologies in many fields such as electronics, aerial and ground transportation as well as construction. These materials require metals which are obtained from various pyrometallurgical processes. Moreover, these materials need to be synthesized under extreme conditions of temperature where liquid solutions are produced and need to be contained. The design and optimization of all these pyrometallurgical processes is a key factor in this development. We present several examples in which computational thermochemistry is used to simulate complex pyrometallurgical processes including the Hall−Heroult process (Al production), the PTVI process (Ni production), and the steel deoxidation from an overall mass balance and energy balance perspective. We also show how computational thermochemistry can assist in the material selection in these extreme operation conditions to select refractory materials in co... [more]
An Autoencoder Gated Recurrent Unit for Remaining Useful Life Prediction
Yi-Wei Lu, Chia-Yu Hsu, Kuang-Chieh Huang
March 24, 2021 (v1)
Keywords: autoencoder, deep learning, gated recurrent unit, predictive maintenance, remaining useful life
With the development of smart manufacturing, in order to detect abnormal conditions of the equipment, a large number of sensors have been used to record the variables associated with production equipment. This study focuses on the prediction of Remaining Useful Life (RUL). RUL prediction is part of predictive maintenance, which uses the development trend of the machine to predict when the machine will malfunction. High accuracy of RUL prediction not only reduces the consumption of manpower and materials, but also reduces the need for future maintenance. This study focuses on detecting faults as early as possible, before the machine needs to be replaced or repaired, to ensure the reliability of the system. It is difficult to extract meaningful features from sensor data directly. This study proposes a model based on an Autoencoder Gated Recurrent Unit (AE-GRU), in which the Autoencoder (AE) extracts the important features from the raw data and the Gated Recurrent Unit (GRU) selects the i... [more]
Functionalized N-Pyridinylmethyl Engrafted Bisarylmethylidenepyridinones as Anticancer Agents
Dhaifallah M. Al-thamili, Abdulrahman I. Almansour, Natarajan Arumugam, Faruq Mohammad, Raju Suresh Kumar
March 24, 2021 (v1)
Subject: Biosystems
Keywords: anticancer studies, apoptosis, caspase-3, functionalized unsaturated ketones, ROS generation
Structurally interesting N-pyridinylmethyl engrafted bisarylmethylidenepyridinones with high functionality have been constructed in good yield. The structural interpretation of these compounds has been done with the aid of spectroscopic analysis and further established by single crystal X-ray diffraction studies. Following physical characterization, the synthesized compounds were tested for their in vitro anticancer activity against HepG2 cancer cells and it was found that all of the compounds exhibited some level of activity. We observed a significant level of cell viability losses to the cancer cells, while only smaller losses to the non-cancer cells were observed. Besides, the mechanistic investigation of toxicology revealed that the cancer cells were undergoing apoptotic pathway, induced by the generation of oxidative stress and the involvement of caspases. The analysis provides preliminary evidence for the successful control of cancer cells with a minimal effect on healthy normal... [more]
Optimization of Extrusion and Ultrasound-Assisted Extraction of Phenolic Compounds from Jizi439 Black Wheat Bran
Xi Chen, Xinyue Li, Xiangwei Zhu, Guozhen Wang, Kun Zhuang, Yuehui Wang, Wenping Ding
March 24, 2021 (v1)
Keywords: extrusion, Jizi439 black wheat, orthogonal experiment, phenolic compounds, ultrasound-assisted extraction
Jizi439, a newly developed black wheat breeding line, was reported to effectively regulate blood glucose, which may potentially be associated with its intrinsic high level of phenolic compounds (PCs). To maximize the PCs yield and thereby enhance their antioxidant activity, orthogonal experiments were designed in sequence for extrusion of Jizi439 black wheat bran (BWB) powder and followed by the extraction of PCs assisted with ultrasound technique. White wheat bran was used as a control. The optimum condition for extrusion was 110 °C, 25% feed water content, 140 rpm screw speed; meanwhile, 50 °C, 40 min, 35 kHz ultrasonic frequency, 300 W ultrasonic power for ultrasound-assisted extraction (UAE). Total phenolic content (TPC) as determined by Folin−Ciocalteu method was 2856.3 ± 57.7 μg gallic acid equivalents (GAE) per gram of dry weight (DW) of phenolic extract; meanwhile, antioxidant activity (AA) in terms of DPPH radical scavenging ratio was 85.5% ± 1.1% under optimized conditions, w... [more]
Firm’s Sustainability and Societal Development from the Lens of Fishbone Eco-Innovation: A Moderating Role of ISO 14001-2015 Environmental Management System
Md. Abu Toha, Satirenjit Kaur Johl, Parvez Alam Khan
March 24, 2021 (v1)
Subject: Other
Keywords: eco-innovation, environment management system, firm sustainability, fishbone diagram, ISO 14001:2015, societal development
Eco-innovation has gained considerable attention in academia as well as in industry due to its potential in mitigating environmental challenges and its positive correlation with firm performance. However, there are limited studies which have investigated the moderating relation of International Organization for Standardization (ISO) 14001:2015 between eco-innovation and firm sustainability in their contribution to societal development. This research is supported by a resource-based theory which explores the core-competencies of firms and challenges the resources creating the competitive advantage of the firm without compromising on the social responsibility aspect of the firm. This study proposes a fishbone eco-innovation business model, which includes production (product, process, and technology) and non-production (organization and marketing) business activities mapped with the 17 Sustainable Development Goals (SDGs) for societal development. This fishbone eco-innovation business mod... [more]
Numerical Investigation on the Sieving Performance of Elliptical Vibrating Screen
Zhiquan Chen, Xin Tong, Zhanfu Li
March 24, 2021 (v1)
Keywords: DEM, DEM–FEM coupling, elliptical vibrating screen, numerical simulation, sieving performance, technical parameter
Screening techniques have been widely deployed in industrial production for the size-separation of granular materials such as coal. The elliptical vibrating screen has been regarded as an excellent screening apparatus in terms of its high screening efficiency and large processing capacity. However, its fundamental mechanisms and operational principles remain poorly understood. In this paper, the sieving process of an elliptical vibrating screen was numerically simulated based on the discrete element method (DEM), and an approach coupling the DEM and the finite element method (DEM−FEM) was introduced to further explore the collision impact of materials on the screen deck. The screening time, screening efficiency, maximum stress and maximum deformation were examined for the evaluation of sieving performance. The effects of six parameters—length of the semi-major axis, length ratio between two semi-axes, vibration frequency, inclination angle, vibration direction angle and vibration direc... [more]
Fed-Batch Sucrose Crystallization Model for the B Massecuite Vacuum Pan, Solution by Deterministic and Heuristic Methods
Paulo Eduardo de Morais Gonzales, Marcos Antônio de Souza Peloso Jr, José Eduardo Olivo, Cid Marcos Gonçalves Andrade
March 24, 2021 (v1)
Keywords: crystallization, deterministic method, fed-batch, metaheuristic method, Modelling, sucrose
Fed-batch crystallization is a crucial step for sugar production. In order to relate parameters that are difficult to measure (average diameter of the crystals and total mass formed) to other easier to measure parameters (volume, temperature, and concentration), a model was developed for a B massecuite vacuum pan composed of mass and energy balances together with empirical relations that describe the crystal development inside equipment. The generated system of ordinary differential equations (ODE) had eight parameters which were adjusted through minimization of relative differences between the model results and experimental data. It was solved through the function fmincon, available in MATLABTM, which is a deterministic and gradient-based optimization method. The objective of this paper is to improve the model obtained and, for this purpose, two metaheuristic functions were used: genetic algorithm and particle swarm. To compare the results, the convergence time of each algorithm was u... [more]
Applications of an Improved Aerodynamic Optimization Method on a Low Reynolds Number Cascade
Shuyi Zhang, Bo Yang, Hong Xie, Moru Song
March 24, 2021 (v1)
Subject: Other
Keywords: aerodynamic, cascade, incidence angle, Optimization, parameterization, plane cascade design, PSO-MVFSA
The effect of cascade aerodynamic optimization on turbomachinery design is very significant. However, for most traditional cascade optimization methods, aerodynamic parameters are considered as boundary conditions and rarely directly used as the optimization variables to realize optimization. Given this problem, this paper proposes an improved cascade aerodynamic optimization method in which an incidence angle and nine geometric parameters are used to parameterize the cascade and one modified optimization algorithm is adopted to find the cascade with the optimal aerodynamic performance. The improved parameterization approach is based on the Non-Uniform Rational B-Splines (NURBS) method, the camber line superposing thickness distribution molding (CLSTDM) method, and the plane cascade design method. To rapidly and effectively find the cascade with the largest average lift-drag ratio within a certain range of incidence angles, modified particle swarm optimization combined with the modifie... [more]
Effect of Regenerated Cellulose Fibers Derived from Black Oat on Functional Properties of PVA-Based Biocomposite Film
Naresh Shahi, Gautam Joshi, Byungjin Min
March 24, 2021 (v1)
Keywords: biopolymers, cellulose, composite films, cover crop, PVA
In this study, agricultural residue from black oat, a cover crop usually grown to improve soil nutrients between the periods of regular crop production, was used as a source of cellulose fibers. Concentrations of 1, 3, and 5 wt. % of regenerated cellulose (RC) fibers blended in poly(vinyl alcohol) (PVA) solution were used to prepare the reinforced composite films (CFs) by the solvent cast method. Compared to neat PVA film (control), the effects of RC addition on functional properties of CFs, such as water absorption, transparency, thermal stability, and mechanical property were investigated. All CFs with different RC concentrations exhibited improved mechanical property and thermal stability while the swelling property was decreased, and no significant changes were observed in the film transparency as compared with the control film. Among the CFs, films with 3% RC significantly decreased water vapor transmission rate, swelling, and soluble fraction (p < 0.05). In addition, Young’s m... [more]
Affinity of Fluoroquinolone−Safirinium Dye Hybrids to Phospholipids Estimated by IAM-HPLC
Krzesimir Ciura, Joanna Fedorowicz, Hanna Kapica, Alicja Adamkowska, Wiesław Sawicki, Jarosław Sączewski
March 24, 2021 (v1)
Subject: Biosystems
Keywords: fluoroquinolone–Safirinium dye hybrids, fluoroquinolones, immobilized artificial membrane
Nowadays, fluoroquinolones (FQs) constitute one of the most important classes of antibiotics. FQs are used to treat infections caused by Gram-positive and Gram-negative species. A set of fluoroquinolone−Safirinium dye hybrids has been synthesized in our laboratory as potential new dual-action antibacterial agents. In the present study we have evaluated how such a modification influences the affinity of FQs to phospholipids. The immobilized artificial membrane (IAM) high-performance liquid chromatography (IAM-HPLC) was used as a tool for the determination of phospholipids partitioning. The obtained results indicate that the fluoroquinolone−Safirinium dye hybrids, especially the SafiriniumP conjugates, display significantly lower affinity to phospholipids than the parent FQs. Despite the fact that the hybrid structures comprise a quaternary nitrogen atom and hence are permanently charged, the attractive electrostatic interactions between the solutes and negatively charged phospholipids d... [more]
Effects of Processing Parameters for Vacuum-Bagging-Only Method on Shape Conformation of Laminated Composites
Yasir Mujahid, Nabihah Sallih, Mazli Mustapha, Mohamad Zaki Abdullah, Faizal Mustapha
March 24, 2021 (v1)
Subject: Other
Keywords: analysis of variance, curing profiles, laminated composite, processing parameters, spring effect, Taguchi orthogonal array, thickness variation, vacuum-bag-only method
Complex composite structures manufactured using a low-pressure vacuum bag-only (VBO) method are more susceptible to defects than flat laminates because of the presence of complex compaction conditions at corners. This study investigates the contribution of multivariate processing parameters such as bagging techniques, curing profiles, and laminate structures on laminates’ shape conformation. Nine sets of laminates were produced with a concave corner and another nine sets with a convex corner, both with a 45° inclined structure. Three-way analysis of variance (ANOVA) was performed to quantify thickness variation and spring effect of laminated composites. The analysis for concave and convex corners showed that the bagging techniques is the main factor in controlling the laminate thickness for complex shape applications. The modified (single) vacuum-bag-only (MSVB) technique appeared to be superior when compared to other bagging techniques, exhibiting the least coefficients of variation o... [more]
Effect of Heavy Metals in the Performance of Anaerobic Digestion of Olive Mill Waste
Khalideh Al bkoor Alrawashdeh, Eid Gul, Qing Yang, Haiping Yang, Pietro Bartocci, Francesco Fantozzi
March 24, 2021 (v1)
Keywords: biogas, biomethanation potential, food industry, toxicity, wastewaters
This study presents an investigation on the effect of heavy metals on the production of biogas during the process of anaerobic digestion (AD) of olive mill waste (OMW). The poisonous effect and the inhibitory influence of Fe, Ni, Pb, Zn, Cu, and Cr on the digestion process are investigated and determined. Biomethanation potential tests are performed for this sake. Adding some of the heavy metals to the AD decreases the efficiency of biogas production and methane concentration and decreases the reduction in the VS, the TCOD, the SCOD, and the organic acid load. A critical increase in the total organic acid and inhibition of methanogenic bacteria was observed due to its toxicity. The toxicity of the heavy metals can be arranged according to increasing order: Cu > Ni > Pb > Cr > Zn > Fe, which leads to rapid poisoning of the active microorganisms. Iron may also exhibit stimulatory effects, but with a low rate and at a certain level. The conclusions of this work are important for the indus... [more]
CO2 Utilization via Integration of an Industrial Post-Combustion Capture Process with a Urea Plant: Process Modelling and Sensitivity Analysis
Reza Shirmohammadi, Alireza Aslani, Roghayeh Ghasempour, Luis M. Romeo
March 24, 2021 (v1)
Keywords: capture efficiency, Carbon Dioxide Capture, CO2 utilization, heat consumption, monoethanol amine, post-combustion
Carbon capture and utilization (CCU) may offer a response to climate change mitigation from major industrial emitters. CCU can turn waste CO2 emissions into valuable products such as chemicals and fuels. Consequently, attention has been paid to petrochemical industries as one of the best options for CCU. The largest industrial CO2 removal monoethanol amine-based plant in Iran has been simulated with the aid of a chemical process simulator, i.e., Aspen HYSYS® v.10. The thermodynamic properties are calculated with the acid gas property package models, which are available in Aspen HYSYS®. The results of simulation are validated by the actual data provided by Kermanshah Petrochemical Industries Co. Results show that there is a good agreement between simulated results and real performance of the plant under different operational conditions. The main parameters such as capture efficiency in percent, the heat consumption in MJ/kg CO2 removed, and the working capacity of the plant are calculat... [more]
Improvement of Polymer Grade L-Lactic Acid Production Using Lactobacillus rhamnosus SCJ9 from Low-Grade Cassava Chips by Simultaneous Saccharification and Fermentation
Kridsada Unban, Narongsak Puangkhankham, Apinun Kanpiengjai, Rasiravathanahalli Kaveriyappan Govindarajan, Dharman Kalaimurugan, Chartchai Khanongnuch
March 24, 2021 (v1)
Keywords: L-lactic acid fermentation, Lactobacillus sp, low-grade cassava chip, RSM
The present study aims to examine the process for L-lactic acid production from low-grade cassava chips (LGC) using a two-step fermentation approach (TSF) and simultaneous saccharification and fermentation (SSF) by proficient, newly isolated Lactobacillus rhamnosus strain SCJ9. The optimized medium composition revealed by response surface methodology for TSF was 166 g/L LGC hydrolysate and 20 g/L yeast extract (YE), while other medium components were fixed (g/L) as follows: tween80 (2.0), (NH4)2HPO4 (2.0), CH3COONa∙3H2O (6.0), (NH4)2HC6H5O7 (2.0), MgSO4∙7H2O (0.5), and MnSO4∙H2O (0.3). Based on the optimization conditions, the maximum experimental L-lactic acid of 134.6 g/L was achieved at 60 h fermentation time with a production efficiency of 89.73%, 0.95 g/g yield and 2.24 g/L/h productivity. In contrast, L-lactic acid production by SSF under optimized concentrations of thermostable-α-amylase (AA) and glucoamylase (GA) gave maximum L-lactic acid of 125.79 g/L at only 36 h fermentatio... [more]
The Effects of Varying Heat Treatments on Lipid Composition during Pelagic Fishmeal Production
Gudrun Svana Hilmarsdottir, Ólafur Ogmundarson, Sigurjón Arason, María Gudjónsdóttir
March 24, 2021 (v1)
Keywords: fish oil, fishmeal, heat treatment, process optimization
The study aimed to provide insight into the lipid quality of pelagic fishmeal and fish oil processing of mackerel and herring cut-offs, and the effect of temperature changes in the cooker (85−95 °C) during production. Samples were collected after each processing step at a traditional processing line where water and lipid content, free fatty acids (FFA), phospholipids (PL) and fatty acid composition (FAC) were measured. Results showed that the standard procedures at 90 °C included ineffective draining and concentration steps. Moreover, the solid streams entering the driers variated in chemical composition, suggesting that processing each stream separately could be beneficial for maintaining the lipid quality. The cooking temperature affected the lipid removal from the fishmeal processing, where lowering the temperature to 85 °C resulted in a lower lipid content of the final fishmeal, along with lower FFA and PL values. Hence, the fishmeal and fish oil factories could save energy by lowe... [more]
Alexandrian Laurel for Biodiesel Production and its Biodiesel Blends on Performance, Emission and Combustion Characteristics in Common-Rail Diesel Engine
Yew Heng Teoh, Heoy Geok How, Thanh Danh Le, Huu Tho Nguyen
March 24, 2021 (v1)
Keywords: Alexandrian Laurel oil, biodiesel, combustion, common-rail, emissions, non-edible
A two-step transesterification process was employed in the biodiesel production from non-edible Alexandrian Laurel. The key physicochemical properties of the Alexandrian Laurel biodiesel (ALB), diesel and blends of both fuels were compared and analyzed. The effects of blending biodiesel (ALB) and petroleum diesel on engine performance, combustion and exhaust emissions were investigated in a turbocharged, high-pressure common-rail diesel engine under six different speed operations and at full load conditions. The test fuels comprised a conventional diesel fuel and four different fuel blends of ALB. The results showed relatively close physicochemical properties of ALB and its blends when compared with petroleum diesel. However, the use of ALB-blended fuel resulted in penalties engine brake power, brake specific fuel consumption (BSFC) despite slightly improved brake thermal efficiency (BTE). Brake specific nitrogen oxide (BSNOx) was found worsened with higher ALB content in the blends. N... [more]
Recent Applications of Magnetic Nanoparticles in Food Analysis
Bárbara Socas-Rodríguez, Antonio V. Herrera-Herrera, María Asensio-Ramos, Miguel Ángel Rodríguez-Delgado
March 24, 2021 (v1)
Keywords: food analysis, magnetic nanoparticles, nanomaterials, sample preparation, sensors, sorbent-based extraction
Nanotechnology has become a topic of interest due to the outstanding advantages that the use of nanomaterials offers in many fields. Among them, magnetic nanoparticles (m-NPs) have been one of the most widely applied in recent years. In addition to the unique features of nanomaterials in general, which exclusively appear at nanoscale, these present magnetic or paramagnetic properties that result of great interest in many applications. In particular, in the area of food analysis, the use of these nanomaterials has undergone a considerable increase since they can be easily separated from the matrix in sorbent-based extractions, providing a considerable simplification of the procedures. This allows reducing cost and giving fast responses, which is essential in the food trade to guarantee consumer safety. These materials can also be easily tunable, providing higher selectivity. Moreover, their particular electrical, thermal and optical characteristics allow enhancing sensor signals, increa... [more]
Modeling and Optimization of COD Removal from Cold Meat Industry Wastewater by Electrocoagulation Using Computational Techniques
Juan Morales-Rivera, Belkis Sulbarán-Rangel, Kelly Joel Gurubel-Tun, Jorge del Real-Olvera, Virgilio Zúñiga-Grajeda
March 24, 2021 (v1)
Keywords: artificial neural network, cold meat industry wastewater, computer modeling, electrocoagulation, Optimization, response surface methodology
In this paper, electrocoagulation (EC) treatment for the removal of chemical oxygen demand (COD) from cold meat industry wastewater is modeled and optimized using computational techniques. Methods such as artificial neural networks (ANNs) and response surface methodology (RSM), based on the Box−Behnken design using three levels, were employed to calculate the best control parameters for pH (5−9), current density (2−6 mA/cm2) and EC time (20−60 min). Analysis of variance (ANOVA) and 3D graphs revealed that pH and current density are the main parameters used for depicting the EC process. The developed models successfully describe the process with a correlation coefficient of R2 = 0.96 for RSM and R2 = 0.99 for ANN. The models obtained were optimized applying the moth-flame optimization (MFO) algorithm to find the best operating conditions for COD removal. ANN-MFO was used and showed superior COD removal (92.91%) under conditions of pH = 8.9, current density = 6.6 mA/cm2 and an EC time of... [more]
A Review of Stereolithography: Processes and Systems
Jigang Huang, Qin Qin, Jie Wang
March 24, 2021 (v1)
Keywords: additive manufacturing, continuous, projection, scanning, stereolithography
Being the earliest form of additive manufacturing, stereolithography (SLA) fabricates 3D objects by selectively solidifying the liquid resin through a photopolymerization reaction. The ability to fabricate objects with high accuracy as well as a wide variety of materials brings much attention to stereolithography. Since its invention in the 1980s, SLA underwent four generations of major technological innovation over the past 40 years. These innovations have thus resulted in a diversified range of stereolithography systems with dramatically improved resolution, throughput, and materials selection for creating complex 3D objects and devices. In this paper, we review the four generations of stereolithography processes, which are scanning, projection, continuous and volumetric stereolithography. For each generation, representative stereolithography system configurations are also discussed in detail. In addition, other derivative technologies, such as scanning−projection, multi-material, an... [more]
Novel Application of Pretreatment and Diagnostic Method Using Dynamic Pressure Fluctuations to Resolve and Detect Issues Related to Biogenic Residue Ash in Chemical Looping Gasification
Andrea Di Giuliano, Ibai Funcia, Raúl Pérez-Vega, Javier Gil, Katia Gallucci
March 14, 2021 (v1)
Keywords: agglomeration, ash behavior, biogenic residues, chemical looping gasification, oxygen carriers, pressure fluctuation analysis, pretreatments for biomasses
Biogenic residues are a promising feedstock to produce liquid biofuels via chemical looping gasification (CLG), but they form ashes with a high inorganic matter content, thus causing agglomeration and deposition in CLG-fluidized beds made of oxygen carriers (OC). The aim of this work is to develop pretreatments for residual biomasses to prevent this issue. Raw forest pine (as a reference material) and wheat straw residues were considered. The latter were pretreated by torrefaction at 250, 260, or 270 °C and through the washing of torrefied biomasses. Torrefaction encouraged a de-chlorinating effect, while washing allowed the removal of 30−40% of S, 60−70% of K, and 40−50% of P. The analysis of pressure fluctuation signals (standard deviations and dominant frequencies) was utilized to verify the improvement of the performance of treated biomass in fluidized beds: three OCs were, respectively, coupled with ashes from all biomasses, then fluidized from 700 to 1000 °C at two and three time... [more]
Influence of β-Stabilizers on the α-Ti→ω-Ti Transformation in Ti-Based Alloys
Askar Kilmametov, Alena Gornakova, Mikhail Karpov, Natalia Afonikova, Anna Korneva, Pawel Zięba, Brigitte Baretzky, Boris Straumal
March 14, 2021 (v1)
Subject: Materials
Keywords: high-pressure torsion, mass transfer, Ti-alloys, α-Ti→ω-Ti transformation, β-stabilizers
The development of next generation Ti-based alloys demand completely new processes and approaches. In particular, the Ti-alloys of next generation will contain not only α-Ti and β-Ti phases, but also small amounts of ω-phase and intermetallic compounds. The β→ω phase transformation induced by high-pressure torsion (HPT) has been studied in detail recently. In this work, we investigated the HPT-induced α→ω phase transformation. For this purpose, we added various β-stabilizers into α-Ti matrix of studied Ti-alloys. Ti-alloys with 4% Fe, 2% Cr, 3% Ni, and 4% Co (wt. %) have been annealed at the temperatures below their point of eutectoid decomposition, from β-Ti to α-Ti, and respective intermetallics (TiFe, Ti2Co, Ti2Ni, TiCr2). Volume fraction of HPT-driven ω-phase (from ≤5 up to ~80%) depended on the amount of alloying element dissolved in the α-matrix. Evaluation of lattice parameters revealed accelerated mass transfer during HPT at room temperature corresponding to bulk diffusion in α... [more]
Optimization Algorithm and Joint Simulation to Micro Thermal Deformation Using Temperature Measurement in the Orifice of Hydraulic Valve
Qianpeng Chen, Hong Ji, Hongke Zhao, Jing Zhao
March 14, 2021 (v1)
Keywords: hydraulic valve orifice, joint simulation, micro thermal deformation, optimization algorithm, temperature measurement
When exposed to viscous heating, hydraulic valve orifices experience thermal deformation, which causes spool clamping and actuator disorder. Quantitative research on thermal deformation can help reveal the micro-mechanism of spool clamping. In this study, miniature thermocouples are embedded into a valve orifice with an opening size of 1 mm to measure temperature distribution. An optimization algorithm based on measurement data (M-OA) for the thermal deformation of the valve orifice is proposed. The temperature and thermal deformation of the valve orifice are calculated through Fluent and Workbench joint simulation, with the measurement data serving as boundary conditions. Results show that, for a valve orifice with a valve wall length of 18 mm, when the temperature of the sharp edge is at 60 °C, thermal deformation measures 7.7 μm via observation and 7.62803 μm via M-OA, indicating that the M-OA method is reliable. The results of the joint simulation can be accepted because measuremen... [more]
Soybean Oil Epoxidation: Kinetics of the Epoxide Ring Opening Reactions
Elio Santacesaria, Rosa Turco, Vincenzo Russo, Riccardo Tesser, Martino Di Serio
March 14, 2021 (v1)
Keywords: epoxides, hydrogen peroxide, kinetics, ring opening reaction, soybean oil
The epoxide ring opening reaction (ROR) can be considered as the most important side reaction occurring in the epoxidation of soybean oil reaction network. This reaction consistently reduces the selectivity to epoxidized soybean oil (ESBO). The reaction is also important for producing polyols and lubricants. In this work, the reaction was studied in different operative conditions to evaluate the effect on ROR rate respectively: (i) The Bronsted acidity of the mineral acid (H2SO4 or H3PO4), used as catalyst for promoting the oxidation with hydrogen peroxide of formic to performic acid, that is, the reactant in the epoxide formation; (ii) the concentration of the nucleophilic agents, normally present during the ESBO synthesis like HCOOH, HCOOOH, H2O, H2O2; (iii) the stirring rate that changes the oil−water interface area and affects the mass transfer rate; (iv) the adopted temperature. Many different kinetic runs were made in different operative conditions, starting from an already epoxi... [more]
Autonomous Indoor Scanning System Collecting Spatial and Environmental Data for Efficient Indoor Monitoring and Control
Dongwoo Park, Soyoung Hwang
March 14, 2021 (v1)
Keywords: autonomous scanning, environmental data, indoor spatial data, IoT (Internet of Things), mobile application, sensor
As various activities related to entertainment, business, shopping, and conventions are done increasingly indoors, the demand for indoor spatial information and indoor environmental data is growing. Unlike the case of outdoor environments, obtaining spatial information in indoor environments is difficult. Given the absence of GNSS (Global Navigation Satellite System) signals, various technologies for indoor positioning, mapping and modeling have been proposed. Related business models for indoor space services, safety, convenience, facility management, and disaster response, moreover, have been suggested. An autonomous scanning system for collection of indoor spatial and environmental data is proposed in this paper. The proposed system can be utilized to collect spatial dimensions suitable for extraction of a two-dimensional indoor drawing and obtainment of spatial imaging as well as indoor environmental data on temperature, humidity and particulate matter. For these operations, the sys... [more]
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