Records Added in August 2021
Records added in August 2021
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Ad-Dressing Stem Cells: Hydrogels for Encapsulation
Leonidas Kandilogiannakis, Eirini Filidou, George Kolios, Vasilis Paspaliaris
August 2, 2021 (v1)
Subject: Biosystems
Keywords: biomaterials, encapsulation, hydrogels, stem cells
Regenerative medicine is a novel scientific field that employs the use of stem cells as cell-based therapy for the regeneration and functional restoration of damaged tissues and organs. Stem cells bear characteristics such as the capacity for self-renewal and differentiation towards specific lineages and, therefore, serve as a backup reservoir in case of tissue injuries. Therapeutically, they can be autologously or allogeneically transplanted for tissue regeneration; however, allogeneic stem cell transplantation can provoke host immune responses leading to a host-versus-transplant reaction. A probable solution to this problem is stem cell encapsulation, a technique that utilizes various biomaterials for the creation of a semi-permeable membrane that encases the stem cells. Stem cell encapsulation can be accomplished by employing a great variety of natural and/or synthetic hydrogels and offers many benefits in regenerative medicine, including protection from the host’s immune system and... [more]
Quantitative Determination of Vitamins A and E in Ointments Using Raman Spectroscopy
Sylwester Mazurek, Kamil Pichlak, Roman Szostak
August 2, 2021 (v1)
Keywords: chemometrics, multivariate calibration, ointments, quantitative analysis, Raman spectroscopy, vitamin A, vitamin E
A quantitative analysis of vitamins A and E in commercial ointments containing 0.044% and 0.8% (w/w) of active pharmaceutical ingredients, respectively, was performed using partial least squares models based on FT Raman spectra. Separate calibration systems were prepared to determine the amount of vitamin A in a petrolatum base ointment and to quantify vitamins A and E in a eucerin base one. Compositions of the laboratory-prepared and commercial samples were controlled through a principal component analysis. Relative standard errors of prediction were calculated to compare the predictive ability of the obtained regression models. For vitamin A determination, these errors were found to be in the 3.8−5.0% and 5.7−5.9% ranges for the calibration and validation data sets, respectively. In the case of vitamin E modeling, these errors amounted to 3.7% and 4.4%. On the basis of elaborated models, vitamins A and E were successfully quantified in two commercial products with recoveries in the 9... [more]
Microalgae Biomolecules: Extraction, Separation and Purification Methods
Priscila S. Corrêa, Wilson G. Morais Júnior, António A. Martins, Nídia S. Caetano, Teresa M. Mata
August 2, 2021 (v1)
Subject: Biosystems
Keywords: biomolecules, cell disruption, chromatography, microalgae, purification, supercritical fluids
Several microalgae species have been exploited due to their great biotechnological potential for the production of a range of biomolecules that can be applied in a large variety of industrial sectors. However, the major challenge of biotechnological processes is to make them economically viable, through the production of commercially valuable compounds. Most of these compounds are accumulated inside the cells, requiring efficient technologies for their extraction, recovery and purification. Recent improvements approaching physicochemical treatments (e.g., supercritical fluid extraction, ultrasound-assisted extraction, pulsed electric fields, among others) and processes without solvents are seeking to establish sustainable and scalable technologies to obtain target products from microalgae with high efficiency and purity. This article reviews the currently available approaches reported in literature, highlighting some examples covering recent granted patents for the microalgae’s compone... [more]
Static and Dynamic Analysis of a 6300 KN Cold Orbital Forging Machine
Zhiqiang Gu, Mingzhang Chen, Chaoyang Wang, Wuhao Zhuang
August 2, 2021 (v1)
Keywords: cold orbital forging, dynamic model, experimental analysis, finite element analysis, machine vibration, numerical simulation, static analysis, theoretical analysis
In cold orbital forging (COF) processes, large stress, displacement and vertical vibration of the COF machine are bad for the quality of the part and the fatigue life of the COF machine. It is necessary to investigate the static and dynamic performance of the COF machine and provide methods for reducing the stress, displacement and vertical vibration of the COF machine. In this paper, finite element analysis, theoretical analysis, numerical simulation and experimental analysis were applied to study the static and dynamic performance of a 6300 KN COF machine. The static and dynamic analyses were verified effectively by carrying out strain and vertical vibration test experiments. In the static analysis, the large stress and displacement positions of the COF machine were mainly distributed near the working table and the junction between the working table and the column. Large stress and displacement will be bad for the quality of the part and the fatigue life of the COF machine. Structura... [more]
Microscopic Characteristics and Properties of Fe-Based Amorphous Alloy Compound Reinforced WC-Co-Based Coating via Plasma Spray Welding
Yan Xu, Yinfeng Wang, Yi Xu, Mingyong Li, Zheng Hu
August 2, 2021 (v1)
Subject: Materials
Keywords: Fe-based amorphous alloy, microstructure and properties, plasma spray welding, WC-Co coating
Plasma spray welding, as one of the material surface strengthening techniques, has the advantages of low alloy material consumption, high mechanical properties and good coating compactness. Here, the Co alloy, WC and Fe-based amorphous alloy composite coating is prepared by the plasma spray welding method, and the coating characteristics are investigated. The results indicate that the coatings have a full metallurgical bond in the coating/substrate interface, and the powder composition influences the microstructures and properties of the coating. The hardness of coatings increases with the mass fraction of the Fe-based amorphous alloy. The spray welding layer has a much higher wear resistance compared with the carbon steel, and the Fe-20 exhibits a superior wear resistance when compared to others. The results indicate that the amorphous alloy powders are an effective additive to prepare the coating by plasma spray welding for improving the wear resistance of the coating.
A Model of Transport of Particulate Biomass in a Stream of Fluid
Tomasz Reguła, Jarosław Frączek, Jakub Fitas
August 2, 2021 (v1)
Keywords: air stream, Modelling, particle motion, pneumatic separation, two-phase mixtures
The motion of a solid particle introduced into a stream of fluid is a crucial problem in the contexts of pneumatic transport and the purification and separation of non-uniform mixtures. However, the complexity of the underlying equations of motion enforces the creation of semi-empirical models. Therefore, analysis of particle motion in a pneumatic channel was performed. To reduce the number of independent variables, several simplifying assumptions were made in regard to both the particle and the stream. The resulting model provides trajectory equations for a particle introduced into the stream at given values of the initial angle and initial velocity, which are then solved using numerical integration methods. A hodograph function was formulated on the basis of the Runge−Kutta and NDFs methods to test the correctness of the solutions under various initial parameters and to provide a universal method of solving the equations of motion. To verify the model, terminal velocities were measur... [more]
Relationships between the Number and Power of Hungarian Household-Sized Photovoltaic Power Plants and Selected Indicators of the Settlements: A Case Study
Nóra Hegedűsné Baranyai, Henrik Zsiborács, András Vincze, Nóra Rodek, Martina Makai, Gábor Pintér
August 2, 2021 (v1)
Keywords: economic, Hungary, infrastructural settlement indicators, photovoltaic system, small-scale power plant, solar energy
In the global transformation of energy systems, solar energy plays a prominent role, since the energy from our star is a limitless and clean resource, which is available practically almost everywhere. In spite of the immense advancements of photovoltaic systems, which utilize this source of energy, no in-depth research has been carried out regarding the present Hungarian status of the small-scale photovoltaic power plants, the most common type of solar power plant in Hungary. The novelty of this study is that it examines the number and power of these small-scale power plants at the settlement level within the service areas of the various distribution companies, by also considering the economic and infrastructural dimensions of the settlements. The paper seeks answers to the questions whether there are any significant relationships between the number and the power of power plants of this type and the indicators of the settlements, and if so, how strong they are. Besides pairwise correla... [more]
Optimising Tropical Fruit Juice Quality Using Thermosonication-Assisted Extraction via Blocked Face-Centered Composite Design
Norazlin Abdullah, Nyuk Ling Chin
August 2, 2021 (v1)
Keywords: guava, pomelo, response surface methodology, soursop, ultrasound
Extraction of tropical fruit juice using simple, efficient, and environmentally friendly technologies is gaining importance to produce high quality juices. Juice from pink-fleshed guava, pink-fleshed pomelo, and soursop was extracted using direct and indirect thermosonication methods by varying intensity, time, and temperature, and compared to those extracted using water bath incubation. Improvised models of juice yield, ascorbic acid, and total soluble solids responses were generated by eliminating insignificant model terms of the factors in full quadratic model using backward eliminating procedure. Main effects, 3D, or 4D plots for each response were developed based on factors that influenced the response. Results showed that the best extraction method for guava and pomelo juices were within indirect thermosonication method of 1 kW, 55 °C and 30 min, and 2.5 kW, 54 °C and 23 min, respectively. Direct thermosonication method at 10% amplitude, 55 °C for 2 to 10 min was more suitable fo... [more]
Time of Flight Size Control of Carbon Nanoparticles Using Ar+CH4 Multi-Hollow Discharge Plasma Chemical Vapor Deposition Method
Sung Hwa Hwang, Kazunori Koga, Yuan Hao, Pankaj Attri, Takamasa Okumura, Kunihiro Kamataki, Naho Itagaki, Masaharu Shiratani, Jun-Seok Oh, Susumu Takabayashi, Tatsuyuki Nakatani
August 2, 2021 (v1)
Subject: Materials
Keywords: carbon nanoparticle, coagulation, optical emission spectroscopy, plasma chemical vapor deposition
As the application of nanotechnology increases continuously, the need for controlled size nanoparticles also increases. Therefore, in this work, we discussed the growth mechanism of carbon nanoparticles generated in Ar+CH4 multi-hollow discharge plasmas. Using the plasmas, we succeeded in continuous generation of hydrogenated amorphous carbon nanoparticles with controlled size (25−220 nm) by the gas flow. Among the nanoparticle growth processes in plasmas, we confirmed the deposition of carbon-related radicals was the dominant process for the method. The size of nanoparticles was proportional to the gas residence time in holes of the discharge electrode. The radical deposition developed the nucleated nanoparticles during their transport in discharges, and the time of flight in discharges controlled the size of nanoparticles.
The Effect of Slurry Wet Mixing Time, Thermal Treatment, and Method of Electrode Preparation on Membrane Capacitive Deionisation Performance
Ebrahiem Botha, Nafeesah Smith, Bongibethu Hlabano-Moyo, Bernard Bladergroen
August 2, 2021 (v1)
Subject: Other
Keywords: capacitive deionisation, contact angle, maximum salt adsorption capacity, thermal treatment, wet mixing
Capacitive deionisation (CDI) electrodes with identical composition were prepared using three deposition methods: (1) slurry infiltration by calendering (SIC), (2) ink infiltration dropwise (IID), and (3) ink deposition by spray coating (IDSC). The SIC method clearly showed favourable establishment of an electrode with superior desalination capacity. Desalination results showed that electrodes produced from slurries mixed longer than 30 min displayed a significant reduction in the maximum salt adsorption capacity, due to the agglomeration of carbon black. The electrodes were then thermally treated at 130, 250, and 350 °C. Polyvinylidene difluoride (PVDF) decomposition was observed when the electrodes were treated at temperatures higher than 180 °C. The electrodes treated at 350 °C showed contact angles of θ = 0°. The optimised electrodes showed a salt adsorption capacity value of 24.8 mg/g (130 °C). All CDI electrodes were analysed using specific surface area by N2 adsorption, contact... [more]
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