Records Added in May 2021
Records added in May 2021
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Showing records 26 to 50 of 160. [First] Page: 1 2 3 4 5 6 Last
Water Vapor Pathways during Freeze-Drying of Foamed Product Matrices Stabilized by Maltodextrin at Different Concentrations
Peter Kubbutat, Annika Tauchnitz, Ulrich Kulozik
May 27, 2021 (v1)
Keywords: channel formation, cracks, foam drying, freeze-drying, maltodextrin, process acceleration
This study aimed to identify the water-vapor transport mechanisms through an aerated matrix during microwave freeze-drying. Due to the larger surface area and lower water vapor transport resistance of an aerated product compared to the solution, foam structures dry faster. Different foam structures were produced with different maltodextrin (MD) concentrations (10−40%) as a foam-stabilizing agent. Depending on the initial viscosity of the solution prior to foaming, the samples differed in overrun (41−1671%) and pore size (d50 = 58−553 µm). Experiments were partially performed in a freeze-drying chamber of a light microscope to visualize structural changes in-situ. Different mechanisms were identified explaining the accelerated drying of foams, depending on the MD concentration, above or below 30%. At lower MD concentration, high overruns could be produced prior to freezing with big bubbles and thin lamellae with short diffusion pathway length. At 40% MD concentration, the viscosity was... [more]
Supercritical Carbon Dioxide(s-CO2) Power Cycle for Waste Heat Recovery: A Review from Thermodynamic Perspective
Liuchen Liu, Qiguo Yang, Guomin Cui
May 27, 2021 (v1)
Keywords: supercritical carbon dioxide power cycle, thermodynamic cycle, waste heat recovery
Supercritical CO2 power cycles have been deeply investigated in recent years. However, their potential in waste heat recovery is still largely unexplored. This paper presents a critical review of engineering background, technical challenges, and current advances of the s-CO2 cycle for waste heat recovery. Firstly, common barriers for the further promotion of waste heat recovery technology are discussed. Afterwards, the technical advantages of the s-CO2 cycle in solving the abovementioned problems are outlined by comparing several state-of-the-art thermodynamic cycles. On this basis, current research results in this field are reviewed for three main applications, namely the fuel cell, internal combustion engine, and gas turbine. For low temperature applications, the transcritical CO2 cycles can compete with other existing technologies, while supercritical CO2 cycles are more attractive for medium- and high temperature sources to replace steam Rankine cycles. Moreover, simple and regener... [more]
Denoising of Hydrogen Evolution Acoustic Emission Signal Based on Non-Decimated Stationary Wavelet Transform
Zazilah May, Md Khorshed Alam, Noor A’in A. Rahman, Muhammad Shazwan Mahmud, Nazrul Anuar Nayan
May 26, 2021 (v1)
Keywords: acoustic emission, denoising, hydrogen evolution, SHM, stationary wavelet transform
Monitoring the evolution of hydrogen gas on carbon steel pipe using acoustic emission (AE) signal can be a part of a reliable technique in the modern structural health-monitoring (SHM) field. However, the extracted AE signal is always mixed up with random extraneous noise depending on the nature of the service structure and experimental environment. The noisy AE signals often mislead the obtaining of the desired features from the signals for SHM and degrade the performance of the monitoring system. Therefore, there is a need for the signal denoising method to improve the quality of the extracted AE signals without degrading the original properties of the signals before using them for any knowledge discovery. This article proposes a non-decimated stationary wavelet transform (ND-SWT) method based on the variable soft threshold function for denoising hydrogen evolution AE signals. The proposed method filters various types of noises from the acquired AE signal and removes them efficiently... [more]
Cellulosic Ethanol: Improving Cost Efficiency by Coupling Semi-Continuous Fermentation and Simultaneous Saccharification Strategies
Patricia Portero Barahona, Bernardo Bastidas Mayorga, Jesús Martín-Gil, Pablo Martín-Ramos, Enrique Javier Carvajal Barriga
May 26, 2021 (v1)
Keywords: bioethanol, enzymes, pretreatment, semi-continuous culture, sugarcane bagasse
A novel approach to improve ethanol production from sugarcane bagasse is proposed. Biomass was pretreated with sodium hydroxide, sulfuric, oxalic, and maleic acids (1% w/v) at different temperatures (130−170 °C) and times (10−30 min). The pretreatment with NaOH at 160 °C for 20 min was found to be the most efficient for further enzymatic saccharification. A semi-continuous fermentation system coupled with a simultaneous saccharification and fermentation strategy was used, attaining fermented liquor every 24 h. The amount of enzymes needed for saccharification was optimized, as well as the production time and ethanol concentration. The process occurred with near to complete depletion of glucose, obtaining ethanol concentrations ranging from 8.36 to 10.79% (v/v). The whole system, at bench scale, showed stability over 30 days, and ease of management and control. This strategy may improve cost efficiency in the production of cellulosic ethanol at industrial scale.
Enhancement of Biomass and Lipid Productivities of Scenedesmus sp. Cultivated in the Wastewater of the Dairy Industry
Ingrid Mercado, Xavier Álvarez, María-Eloiza Verduga, Andrea Cruz
May 26, 2021 (v1)
Keywords: lipid production, microalgae, nutrient removal, Scenedesmus sp., Wastewater
Microalgae are photoautotrophic microorganisms capable of producing compounds with potential bioenergetic applications as an alternative energy source due to the imminent exhaustion of fossil fuels, their impact on the environment, and the constant population increase. The mass cultivation of these microorganisms requires high concentrations of nutrients, which is not profitable if analytical grade culture media are used. A viable alternative is the use of agro-industrial wastewater, due to the metabolic flexibility of these microorganisms and their ability to take advantage of the nutrients present in these substrates. For the reasons mentioned above, the effect of the cultivation in wastewater from cheese processing on the growth parameters and biomass composition of Scenedesmus sp. was evaluated, and its nutrient removal capacity determined. A high lipid concentration was obtained in the cultures with the dairy effluent (507.81 ± 19.09 mg g−1) compared to the standard culture medium... [more]
Analysis of Selected Physicochemical Properties of Commercial Apple Juices
Leszek Rydzak, Zbigniew Kobus, Rafał Nadulski, Kamil Wilczyński, Anna Pecyna, Francesco Santoro, Agnieszka Sagan, Agnieszka Starek-Wójcicka, Monika Krzywicka
May 26, 2021 (v1)
Keywords: antiradical activity, commercial apple juice, correlation analysis, DPPH, total phenolic contents
The paper presents the comparison of quality of six different commercial apple juices produced in Poland. The apple juices came from two different Polish companies. From each manufacturer three various juices were selected: two cloudy and clarified one produced as a mixture of different apple varieties. The following properties were evaluated: density, soluble solid content, viscosity, total phenolic contents, phenolic acid, and antiradical activity. The obtained results showed that three from fourth cloudy juices (M1Sz, M1A and M2A) differed from clarified juices. The highest differences were noticed for total phenolic contents, phenolic acids, antiradical activity and viscosity. The values of these properties ranged between 60.72−103.6 mg GAE·100−1 mL−1 for phenolic contents, 78.3−90.9% for antiradical activity and 2.68−5.79 mPa·s for viscosity. The remaining cloudy juice (M2Sz) was more similar to the clarified ones. The strong correlation between total phenolic content and antiradi... [more]
Dielectric Spectroscopy to Improve the Production of rAAV Used in Gene Therapy
Daniel A. M. Pais, Chris Brown, Anastasia Neuman, Krishanu Mathur, Inês A. Isidro, Paula M. Alves, Peter G. Slade
May 26, 2021 (v1)
Subject: Biosystems
Keywords: AAV—adeno-associated virus, cell culture monitoring, dielectric spectroscopy, gene therapy, insect cell-baculovirus, process analytical technology
The insect cell-baculovirus expression vector system is an established method for large scale recombinant adeno-associated virus (rAAV) production, largely due to its scalability and high volumetric productivities. During rAAV production it is critical to monitor process parameters such as Spodoptera frugiperda (Sf9) cell concentration, infection timing, and cell harvest viabilities since they can have a significant influence on rAAV productivity and product quality. Herein we developed the use of dielectric spectroscopy as a process analytical technology (PAT) tool used to continuously monitor the production of rAAV in 2 L stirred tank bioreactors, achieving enhanced control over the production process. This study resulted in improved manufacturing robustness through continuous monitoring of cell culture parameters, eliminating sampling needs, increasing the accuracy of infection timing, and reliably estimating the time of harvest. To increase the accuracy of baculovirus infection tim... [more]
Horseradish Peroxidase-Decorated Artificial Viral Capsid Constructed from β-Annulus Peptide via Interaction between His-Tag and Ni-NTA
Kazunori Matsuura, Yuriko Shiomi, Toshihumi Mizuta, Hiroshi Inaba
May 26, 2021 (v1)
Subject: Biosystems
Keywords: artificial viral capsid, horseradish peroxidase, nanocapsule, self-assembly, surface decoration, β-annulus peptide
Artificial construction of spherical protein assemblies has attracted considerable attention due to its potential use in nanocontainers, nanocarriers, and nanoreactors. In this work, we demonstrate a novel strategy to construct peptide nanocapsules (artificial viral capsids) decorated with enzymes via interactions between His-tag and Ni-NTA. A β-annulus peptide derived from the tomato bushy stunt virus was modified with Ni-NTA at the C-terminus, which is directed toward the exterior surface of the artificial viral capsid. The β-annulus peptide bearing Ni-NTA at the C-terminus self-assembled into capsids of about 50 nm in diameter. The Ni-NTA-displayed capsids were complexed with recombinant horseradish peroxidase (HRP) with a C-terminal His-tag which was expressed in Escherichia coli. The β-annulus peptide-HRP complex formed spherical assemblies whose sizes were 30−90 nm, with the ζ-potential revealing that the HRP was decorated on the outer surface of the capsid.
Effect of Variety on Rehydration Characteristics of Dried Apples
Krzysztof Górnicki, Aneta Choińska, Agnieszka Kaleta
May 26, 2021 (v1)
Keywords: apple, color, material properties, rehydration, variety
The effect of dried apple varieties on their rehydration characteristics was investigated. Four varieties of apples, Champion, Cortland, Grey Reinette and Ligol, were taken into consideration. Rehydration properties and color of apples were investigated. In order to examine the influence of apple variety on its rehydration properties, the process of rehydration was modeled. The model parameters obtained for investigated apple varieties were compared. Apple cubes were dried in a tunnel dryer (air temperature 60 °C and air velocity 2 m/s) and next rehydrated in distilled water at temperature: 20, 45 and 70 °C. Mass, dry matter mass, volume and color attributes of apples (raw, dried and rehydrated) were measured. The process of rehydration was modeled using empirical (Peleg and Weibull models) and theoretical (the Fick’s second law) models. Results of the analysis showed that the apple variety affects values of mass and volume increase, dry matter decrease and color of the rehydrated appl... [more]
Controlled Degradation of Lubricating Media by Means of an Accelerated Electron Beam
Jiří Stodola, Petr Stodola
May 26, 2021 (v1)
Keywords: accelerated electron beam, changes in the properties of the lubricating medium, engines, ionizing radiation
The article deals with the possibilities of using electron accelerator for controlled aging of lubricating media used in special vehicles. During use, e.g., in combustion engines, the lubricants get contaminated and thermo-oxidative degradation also occurs. The pilot project confirms the hypothesis that ionizing radiation makes it possible to simulate the operating load of lubricating media, which was repeatedly confirmed by long-term monitoring of changes in viscosity of statistically significant samples of motor oils used in special equipment. Preliminary test results also show that there are likely to be possibilities to influence other selected properties, such as the coefficient of friction depending on the radiation dose. The authors describe physicochemical processes during irradiation and, in the example of kinematic viscosity, present summary results for selected lubricating media.
Remediation of Lead and Nickel Contaminated Soil Using Nanoscale Zero-Valent Iron (nZVI) Particles Synthesized Using Green Leaves: First Results
Nimita Francy, Subramanian Shanthakumar, Fulvia Chiampo, Yendaluru Raja Sekhar
May 26, 2021 (v1)
Keywords: lead, mint, neem, nickel, nZVI synthesis, soil remediation
Nanoscale zero-valent iron (nZVI) particles have proved to be effective in the remediation of chlorinated compounds and heavy metals from contaminated soil. The present study aimed to analyze the performance of nanoparticles synthesized from low-cost biomass (green leaves) as chemical precursors, namely Azadirachta indica (neem) and Mentha longifolia (mint) leaves. These leaves were chosen because huge amounts of them are present in the region of Vellore. These nanoparticles were used to remove lead and nickel from contaminated soil. Characterization of nZVI particles was conducted using the Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM), and Brunauer−Emmett−Teller isotherm (BET) techniques. Remediation was performed on two different soil samples, polluted with lead or nickel at an initial metal concentration around 250 mg/kg of soil. The results revealed that after 30 days, the lead removal efficiency with 0.1 g of nZVI particles/kg of soil was 26.9% by par... [more]
Processing, Characteristics and Composition of Umqombothi (a South African Traditional Beer)
Edwin Hlangwani, Janet Adeyinka Adebiyi, Wesley Doorsamy, Oluwafemi Ayodeji Adebo
May 26, 2021 (v1)
Keywords: Artificial Intelligence, bioprocessing, health, local beer, safety, South Africa, umqombothi
Traditional beers, such as palm wine, kombucha and others, are notable beverages consumed all over the globe. Such beverages historically contribute to food security on a global scale. Umqombothi is a South African traditional beer nutritionally packed with minerals, amino acids, B-group vitamins and much-needed calories. As a result, the production and consumption of this traditional beverage has been an integral part of South African’s social, economic and cultural prosperity. Unfortunately, difficulties in bioprocessing operations have limited its availability to household and small-scale production. It is at these micro-production scales that poor hygiene practices and the use of hazardous additives and contaminated raw materials continue to increase, posing serious health risks to the unassuming consumer. This study provides an overview of the processing steps and underlying techniques involved in the production of umqombothi, while highlighting the challenges as well as future de... [more]
Formulation of Piperine Ternary Inclusion Complex Using β CD and HPMC: Physicochemical Characterization, Molecular Docking, and Antimicrobial Testing
Sultan Alshehri, Syed Sarim Imam, Afzal Hussain, Mohammad A. Altamimi
May 26, 2021 (v1)
Subject: Materials
Keywords: anti-oxidant, antimicrobial, HPMC, inclusion complex, molecular docking, piperine, β CD
The present study was designed to evaluate the effect of hydroxyl propyl methyl cellulose (HPMC) on the complexation efficiency and dissolution of piperine (PPR) and β cyclodextrin (β CD) complex. The binary and ternary inclusion complexes were prepared using solvent evaporation and microwave irradiation methods. The samples were further evaluated for physicochemical evaluation, morphology, antimicrobial, and antioxidant activities. The binary and ternary samples showed high stability constant (Ks) value and complexation efficiency (CE). The dissolution study results revealed marked enhancement in the release of the binary inclusion complex and ternary inclusion complex compared to pure PPR. Fourier transform infrared (FTIR), nuclear magnetic resonance (NMR), and molecular docking results confirm the complex formation. X-ray powder diffractometry (XRD) and scanning electron microscopy (SEM) data revealed modification in the structure of PPR. 2,2-diphenyl-1-picrylhydrazyl (DPPH) scaveng... [more]
Effect of Sialic Acid on Mammalian Cell Culture and Protein Expression: A Potential Productivity Enhancer for Biopharmaceutical Cell Culture Processes
Xiangsong Chen, Shang Xiao, Jinyong Wu, Jianming Yao
May 26, 2021 (v1)
Subject: Biosystems
Keywords: CHO, HEK293, lactate, ROS, sialic acid
Improved productivity of the two most commonly used cell lines in the biopharmaceutical industry, such as human embryonic kidney 293 (HEK293) and Chinese hamster ovary (CHO), could reduce production costs and increase manufacturing capacity. One method for increasing protein productivity is the addition of antioxidants during the cell culture process. In this study, we examined the effect of sialic acid (SA) on one HEK293 cell line and two CHO cell lines. The addition of SA to HEK293 cell led to a higher viable cell density (VCD), viability (Via), and a lower lactate content in the later stage of cultures. Further results showed that SA reduced the reactive oxygen species (ROS), improved cell viability, reduced lactate production, and increased antibody expression by more than 20% in the later stage of the two CHO cell lines cultures. Besides, an optimized dose of SA had no significant effect on acidic variants level aggregation level, N-linked glycosylation pattern, and SA content on... [more]
Methodology for Concurrent Multi-Parametric Physical Modeling of a Target Natural Unfractured Homogeneous Sandstone
Joseph Y. Fu, Xiang’an Yue, Bo Zhang
May 26, 2021 (v1)
Keywords: artificial sandstone, petrophysical modeling, physical modeling, pore throat size distribution modeling, synthetic sandstone
In petroleum, geological and environmental science, flow through porous media is conventionally studied complementarily with numerical modeling/simulation and experimental corefloods. Despite advances in numerical modeling/simulation, experimental corefloods with actual samples are still desired for higher-specificity testing or more complex mechanistic studies. In these applications, the lack of advances in physical modeling is very apparent with the available options mostly unchanged for decades (e.g., sandpacks of unconsolidated packing materials, industry-accepted substitutes with fixed/mismatching petrophysical properties such as Berea sandstone). Renewable synthetic porous media with adjustable parameters are the most promising but have not advanced adequately. To address this, a methodology of advanced physical modeling of the fundamental parameters of dominant mineralogy, particle size distribution, packing, and cementation of a target natural porous media is introduced. Based... [more]
Extraction of Anthocyanins from Red Raspberry for Natural Food Colorants Development: Processes Optimization and In Vitro Bioactivity
Rosiane Rocha, José Pinela, Rui M.V. Abreu, Mikel Añibarro-Ortega, Tânia C.S.P. Pires, Ana Luísa Saldanha, Maria José Alves, António Nogueira, Isabel C.F.R. Ferreira, Lillian Barros
May 26, 2021 (v1)
Keywords: antioxidant/antimicrobial activity, cyanidin glycosides, heat-/ultrasound-assisted extraction, natural colorants, process optimization, Rubus idaeus L.
Heat (HAE)- and ultrasound (UAE)-assisted extraction methods were implemented to recover anthocyanins from red raspberry. Processing time, ethanol concentration, and temperature or ultrasonic power were the independent variables combined in five-level rotatable central composite designs coupled with response surface methodology (RSM) for processes optimization. The extraction yield and levels of cyanidin-3-O-sophoroside (C3S) and cyanidin-3-O-glucoside (C3G) were monitored by gravimetric and HPLC-DAD-ESI/MSn methods, respectively, and used as response criteria. The constructed theoretical models were successfully fitted to the experimental data and used to determine the optimal extraction conditions. When maximizing all responses simultaneously, HAE originated slightly higher response values (61% extract weight and 8.7 mg anthocyanins/g extract) but needed 76 min processing at 38 °C, with 21% ethanol (v/v), while the UAE process required 16 min sonication at 466 W, using 38% ethanol (v... [more]
Improving the Imazapyr Degradation by Photocatalytic Ozonation: A Comparative Study with Different Oxidative Chemical Processes
Salma Bougarrani, Zakarya Baicha, Lahbib Latrach, Mohammed El Mahi, Francisco José Hernandez Fernandez
May 26, 2021 (v1)
Keywords: degradation, imazapyr herbicide, ozonation, photocatalytic ozonation, wastewater treatment
The degradation of imazapyr (C13H15N3O3), an active element in the aqueous solution of commercial herbicide, was investigated. This study was the first to evaluate in a comprehensive manner the efficiency of advanced oxidation processes for imazapyr degradation. Results showed that Imazapyr degradation is significantly affected by operational conditions such as TiO2 concentration, ozone concentration, initial concentration of imazapyr and pH. The kinetics of Imazapyr consumption was the first order with respect to Imazapyr concentration and zero order with respect to ozone concentration with a constant rate of 0.247 min−1 and 0.128 min−1 for photocatalytic ozonation and heterogeneous photocatalysis, while it was the first order with respect to Imazapyr and the first order with respect to ozone concentrations when only ozone was used with a constant rate of 0.053 mol L−1 min−1 at pH 7. The results revealed that more than 90 percent of the removal efficiency representing the elimination... [more]
Influence of Tip Clearance on Flow Characteristics of Axial Compressor
Moru Song, Hong Xie, Bo Yang, Shuyi Zhang
May 26, 2021 (v1)
Keywords: axial compressor, flow field, numerical simulation, tip clearance
This paper studies the influence of tip clearance on the flow characteristics related to the performance. Based on full-passage numerical simulation with experimental validation, several clearance models are established and the performance curves are obtained. It is found that there exists an optimum clearance for the stable working range. By analyzing the flow field in tip region, the role of the tip leakage flow is illustrated. In the zero-clearance model, the separation and blockage along the suction side is the main reason for rotating stall. As the tip clearance is increased to the optimum value, the separation is suppressed by the tip leakage flow. However, with the continuing increasing of the tip clearance, the scale and strength of the tip clearance vortex is increased correspondingly. When the tip clearance is larger than the optimum value, the tip clearance vortex gradually dominates the flow field in the tip region, which can increase the unsteadiness in the tip region and... [more]
Large Eddy Simulation of Film Cooling with Triple Holes: Injectant Behavior and Adiabatic Film-Cooling Effectiveness
Seung Il Baek, Joon Ahn
May 26, 2021 (v1)
Keywords: adiabatic film-cooling effectiveness, blowing ratio, film cooling, large eddy simulation, proper orthogonal decomposition, triple holes
This study investigated the effect of adding two sister holes placed downstream the main hole on film cooling by employing large eddy simulation. Here, film-cooling flow fields from a triple-hole system inclined by 35° to a flat plate at blowing ratios of M = 0.5 and unity were simulated. Each sister hole supplies a cooling fluid at a flow rate that is a quarter of that for the main hole. The simulations were conducted using the Smagorinsky−Lilly model as the subgrid-scale model, and the results were compared with those for a single-hole system for the same amount of total cooling air and same cross-sectional area of the holes. Relative to the single-hole system, the spanwise-averaged film-cooling effectiveness in the triple-hole configuration at M = 1.0 increased by as much as 345%. The subsequent proper orthogonal decomposition analysis showed that the kinetic energy of a counter-rotating vortex pair in the triple-hole system dropped by 30−40% relative to that of the single-hole syst... [more]
Heat Transfer Improvement in MHD Natural Convection Flow of Graphite Oxide/Carbon Nanotubes-Methanol Based Casson Nanofluids Past a Horizontal Circular Cylinder
Abdulkareem Saleh Hamarsheh, Firas A. Alwawi, Hamzeh T. Alkasasbeh, Ahmed M. Rashad, Ruwaidiah Idris
May 26, 2021 (v1)
Keywords: Casson nanofluid, CNTs, constant heat flux, GO, horizontal circular cylinder, Methanol, MHD
This numerical investigation intends to present the impact of nanoparticles volume fraction, Casson, and magnetic force on natural convection in the boundary layer region of a horizontal cylinder in a Casson nanofluid under constant heat flux boundary conditions. Methanol is considered as a host Casson fluid. Graphite oxide (GO), single and multiple walls carbon nanotubes (SWCNTs and MWCNTs) nanoparticles have been incorporated to support the heat transfer performances of the host fluid. The Keller box technique is employed to solve the transformed governing equations. Our numerical findings were in an excellent agreement with the preceding literature. Graphical results of the effect of the relevant parameters on some physical quantities related to examine the behavior of Casson nanofluid flow were obtained, and they confirmed that an augmentation in Casson parameter results in a decline in local skin friction, velocity, or temperature, as well as leading to an increment in local Nusse... [more]
A Charge-Based Mechanistic Study into the Effects of Process Parameters on Fiber Accumulating Geometry for a Melt Electrohydrodynamic Process
Kai Cao, Fucheng Zhang, Robert C. Chang
May 26, 2021 (v1)
Keywords: collector temperature, melt electrohydrodynamic process, polarization, scaffolds
Melt electrohydrodynamic processes, in conjunction with a moveable collector, have promising engineered tissue applications. However, the residual charges within the fibers deteriorate its printing fidelity. To clarify the mechanism through which the residual charges play roles and exclude the confounding effects of collector movement, a stationary printing mode is adopted in which fibers deposit on a stationary collector. Effects of process parameters on generalizable printing outcomes are studied herein. The fiber deposit bears a unique shape signature typified by a central cone surrounded by an outer ring and is characterized by a ratio of its height and base diameter Hdep/Ddep. Results indicate Hdep/Ddep increases with collector temperature and decreases slightly with voltage. Moreover, the steady-state dynamic jet deposition process is recorded and analyzed at different collector temperatures. A charge-based polarization mechanism describing the effect of collector temperature on... [more]
Experimental and Comparative RANS/URANS Investigations on the Effect of Radius of Volute Tongue on the Aerodynamics and Aeroacoustics of a Sirocco Fan
Xiaocheng Rui, Limin Lin, Junkui Wang, Xinxue Ye, Haijiang He, Wei Zhang, Zuchao Zhu
May 26, 2021 (v1)
Keywords: internal flow, noise, Sirocco fan, URANS, volute tongue radius
The geometry of volute tongue is crucial in the design of Sirocco fans. The size of the volute tongue determines its relative position and distance from the impeller which affects the local flow characteristics and thus the aerodynamic and aeroacoustic performances of the fan. In this work, we performed experimental and numerical investigations on the effect of volute tongue radius on the aerodynamic and aeroacoustic characteristics of a Sirocco fan. The internal flow characteristics are analyzed and discussed in terms of the spatial distribution and temporal variation of pressure and streamlines, the pulsating behaviors of pressure both in the impeller and on the volute surface with emphasis in the volute tongue region, the variation of passage flow with the rotation of impeller and the aeroacoustic features of the fan. We conducted numerical simulations using both steady Reynolds-Averaged Navier-Stokes (RANS) and unsteady Reynolds-Averaged Navier-Stokes (URANS) approaches with realiz... [more]
Ultrasound Assisted Extraction of Phenolic Compounds from a Jujube By-Product with Valuable Bioactivities
Farida Berkani, Maria Luisa Serralheiro, Farid Dahmoune, Asma Ressaissi, Nabil Kadri, Hocine Remini
May 26, 2021 (v1)
Keywords: biological activities, jujube, polyphenols, response surface methodology, ultrasound
Jujube plant is a potential source of polyphenols with biological propreties. The purpose of this study was to investigate the application of ultrasound technique for extracting phenolic compounds (TPC) from seeds of Zizyphus lotus under optimization conditions based on response surface methodology. A maximum TPC, total flavonoids content (TFC), and total condensed tannins content (TTC) of 2383.10 ± 0.87 mg GAE/100g, 486.50 ± 0.38 mg QE/100g and 15,787.10 ± 0.10 mg CE/100g, respectively obtained under ethanol concentration 50.16%, sonication temperature 29.01 °C, sonication time 15.94 min and solvent-to-solid ratio 34.10:1 mL/g. The optimized extract was then evaluated for its antioxidant, antiacethylcholinesterase, antihypercholesterolemia, and antiproliferative activities. The results showed that ultrasound method is a green and safe method that can be used to effectively extract TPC from jujube seeds. The biological activity of Zizyphus extract exhibited a very good antioxidant agai... [more]
Comparison of Techniques to Control Ice Nucleation during Lyophilization
Jacob Luoma, Erika Ingham, Carmen Lema Martinez, Andrea Allmendinger
May 26, 2021 (v1)
Subject: Biosystems
Keywords: freeze drying, ice nucleation, Lyophilization, monoclonal antibody formulations, protein stability
Controlling ice nucleation during lyophilization of parenteral drug products increases the homogeneity of critical quality attributes, such as residual moisture, across drug product batches and shortens lyophilization cycle time. In the present study, we compare three mechanistically different techniques to control ice nucleation during the freezing step of lyophilization, which are referred to as “depressurization”, “partial vacuum”, and “ice fog” techniques. The techniques are compared with respect to their operational limitations and challenges. Installation considerations are also discussed. Using the aforementioned nucleation techniques, we investigated a monoclonal antibody formulation and an enzyme formulation at different protein concentrations using feasible nucleation temperatures and different vial formats and fill volumes. Samples were compared for solid state properties and other critical quality attributes on stability. When nucleated at the same temperature, the three te... [more]
Sustainable Production−Inventory Model in Technical Cooperation on Investment to Reduce Carbon Emissions
JiaLiang Pan, Chui-Yu Chiu, Kun-Shan Wu, Hsiu-Feng Yen, Yen-Wen Wang
May 26, 2021 (v1)
Keywords: carbon cap-and-trade, carbon tax, sustainable production–inventory model
Carbon cap-and-trade and carbon offsets are common and important carbon emission reduction policies in many countries. In addition, carbon emissions from business activities can be effectively reduced through specific capital investments in green technologies. Nevertheless, such capital investments are costly and not all enterprises can afford these investments. Therefore, if all members of a supply chain agree to share the investments in the facilities, the supply chain can reduce carbon emissions and generate more profit. Under carbon cap-and-trade and carbon tax policies, this study proposes a production−inventory model in which the buyer and vendor in the integrated supply chain agree to co-invest funds to reduce carbon emissions. We planned to integrate production, delivery, replenishment, and technology to reduce carbon emissions so as to maximize the total profit of the supply chain system. Several examples are simulated and the sensitivity analysis of the main parameters is car... [more]
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