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Showing records 36750 to 36774 of 43292. [First] Page: 1 1467 1468 1469 1470 1471 1472 1473 1474 1475 Last
Darcy−Forchheimer Relation Influence on MHD Dissipative Third-Grade Fluid Flow and Heat Transfer in Porous Medium with Joule Heating Effects: A Numerical Approach
Amir Abbas, Mdi Begum Jeelani, Nadiyah Hussain Alharthi
February 21, 2023 (v1)
Keywords: Darcy–Forchheimer relation, diffusion-thermo, heat transfer, joule heating, mhd, porous medium, thermal-diffusion, third-grade fluid, viscous dissipation
The current investigations are carried out to study the influence of the Darcy−Forchheimer relation on third-grade fluid flow and heat transfer over an angled exponentially stretching sheet embedded in a porous medium. In the current study, the applied magnetic field, Joule heating, thermaldiffusion, viscous dissipation, and diffusion-thermo effects are incorporated. The proposed model in terms of partial differential equations is transformed into ordinary differential equations using suitable similarity transformation. The reduced model is then solved numerically with the help of MATLAB built-in function bvp4c.The numerical solutions for velocity profile, temperature profile, and mass concentration under the effects of pertinent parameters involved in the model are determined and portrayed in graphical form. The graphical effects of the skin friction coefficient, the Nusselt number, and the Sherwood number are also shown. From the displayed results, we conclude that when the Joule hea... [more]
A Novel Graphical Targeting Technique for Optimal Allocation of Biomass Resources
Dominic C. Y. Foo
February 21, 2023 (v1)
Keywords: bioenergy, composite curves, pinch analysis, power generation, process integration
Biomass has gained global attention as one of the most important renewable energy resources that reduces greenhouse gas emissions. Various research works have been dedicated to biomass supply chain in the past decade as to continuously support the deployment of biomass resources for regional applications. In this work, a novel graphical method based on process integration is proposed for targeting the amount of biomass resources needed for a power generation problem. Apart from having a good visualized interface, the graphical method provides good insights to stakeholders on the macro-level planning of biomass allocation. Two examples are solved to demonstrate the newly proposed methods.
Design and Multiobjective Optimization of Green Closed-Loop Manufacturing-Recycling Network Considering Raw Material Attribute
Chen Chen, Yue Wang, Shan Lu, Xinchao Li
February 21, 2023 (v1)
Subject: Materials
Keywords: closed-loop manufacturing, dual-objective optimization, environmental protection, epsilon-constraint method, material attribute
Regarding decision planning in the electronic manufacturing industry, this paper designs a green closed-loop manufacturing-recycling network for multiperiod production planning for multiple products. The network considers the tradeoff between production costs and environmental pollution induced by production scraps. Therefore, a mixed integer programming model with a dual objective is designed to achieve environmental protection and reduce production costs through resource recovery and utilization. At the same time, the recycled materials are considered to be treated, not entirely new, which could affect the manufacturing qualified rate. Thus, material attributes are proposed to distinguish new raw materials from recycled (second-hand) ones through the closed-loop manufacturing-recycling process to enhance the manufacturing qualified rate. In order to solve the dual-objective optimization model and realize optimal decisions, an epsilon constraint is designed to generate a nonextreme so... [more]
Circular Economy Indicators for the Assessment of Waste and By-Products from the Palm Oil Sector
Pedro-Antonio Cárdenas Bejarano, Juan-Pablo Rodriguez-Miranda, Rayma Ireri Maldonado-Astudillo, Yanik Ixchel Maldonado-Astudillo, Ricardo Salazar
February 21, 2023 (v1)
Subject: Environment
Keywords: circular economy, indicator, sustainable development
A circular economy (CE) promotes the reuse, reincorporation and valuation of waste and by-products under the framework of sustainable development through models and indicators that evaluate scenarios of second use and reduction in non-incorporated outputs to reduce negative externalities and pressures on the dimensions of development. A CE model applied to the transformation process of RFF in agro-industries is developed, which consists in the identification of the residue coefficients of EFB (22.48% ± 0.8), fiber (15.58% ± 0.49), husk (6.03% ± 0.66) and ash (0.55% ± 1.67). Subsequently, the valuation trends of potential second use were verified through a systematic review, which allowed the construction of the scenario of avoided costs of USD 678,721.5, a product of the total use of the outputs under bioenergy and nutrient source approaches. Finally, the RRSFM indicator was constructed, which can reach the level of 72% and a degree of improvement of 26% by 2026. In parallel, the HCRRS... [more]
Quantitative Risk Analysis of Oil and Gas Fires and Explosions for FPSO Systems in China
Xiulong Xie, Youming Xiong, Weikang Xie, Junjie Li, Wenhai Zhang
February 21, 2023 (v1)
Keywords: dimensioning accidental loads, fire and explosion risk analysis, LH11-1 FPSO system, quantitative risk assessment
The LH11-1 FPSO is an 80,000 t cylindrical structure that is responsible for the processing, storage, and offloading of process oil from existing and newly developed oilfields. In this paper, a full probabilistic analysis was developed based on very detailed CFD simulation results to evaluate ventilation, gas dispersion, explosion, and fire scenarios. A detailed fire and explosion risk analysis of LH11-1 FPSO was performed based on NORSOK Z-013 and FABIG Technical Note 11. The risk-based calculations were performed applying FLACS, KFX, and DNV GLEXPRESS Fire. Finally, the oil and gas dispersion, fire, and explosion consequence risks were calculated under the credible combination of leak frequency and leak location. By this probabilistic risk analysis, it was found that the west wind could generate optimal ventilation conditions for the topside process area of FPSO compared to other wind directions, while the hull region was poorly ventilated for all wind directions. The explosion risk... [more]
Yeast Biodiversity in Vineyard during Grape Ripening: Comparison between Culture Dependent and NGS Analysis
Antonella Costantini, Enrico Vaudano, Laura Pulcini, Lara Boatti, Elisa Gamalero, Emilia Garcia-Moruno
February 21, 2023 (v1)
Subject: Biosystems
Keywords: “Nizza” Barbera, fungi, grape berries, mycobiota, ripening
In this study, the evolution of the yeast microflora present on the berry surface, during the ripening of Barbera grapes, was monitored. Sampling was performed in three vineyards located in the “Nizza” Barbera d’Asti DOC zone and different methodologies have been employed. A culture-dependent method based on the identification of strains grown on solid media by ARDRA (Amplified Ribosomal DNA Restriction Analysis) and the D1-D2 domain of ribosomal 26S DNA capillary sequencing was coupled to NGS (Next Generation Sequencing) targeting ITS (Internal Transcribed Sequence) amplicons with the Illumina MiSeq platform. By using culture-dependent techniques, the most frequently detected species was the yeast-like fungus Aureobasidium pullulans, which was dominant in the culturable fraction. Among yeasts, the presence of oligotrophic basidiomycetes such as Cryptococcus spp., Rhodotorula graminis and Sporidiobolus pararoseus was observed at the beginning of ripening. Afterward, upon approaching th... [more]
Numerical Investigation on the Impact of Tailings Slurry on Catch Dams Built at the Downstream of a Breached Tailings Pond
Shitong Zhou, Li Li
February 21, 2023 (v1)
Keywords: impacting force, kinetic energy, numerical simulation, smoothed particle hydrodynamics (SPH), tailings dam
Tailings storage facilities (TSFs) are known as a time-bomb. The numerous failures of TSFs and the heavy catastrophic consequences associated with each failure of TSFs indicate that preventing measures are necessary for existing TSFs. One of the preventing measures is to construct catch dams along the downstream near TSFs. The design of catch dams requires a good understanding of the dynamic interaction between the tailings slurry flow and the catch dams. There are, however, very few studies on this aspect. In this study, a numerical code, named LS-DYNA, that is based on a combination of smoothed particle hydrodynamics and a finite element method, was used. The numerical modeling shows that the tailings slurry flow can generally be divided into four stages. In terms of stability analysis, a catch dam should be built either very close to or very far from the TSF. When the catch dam with an upstream slope of a very small inclination angle is too close to the tailings pond, it can be nece... [more]
Application of Monitoring Module Three-in-One Microsensor to Real-Time Microscopic Monitoring of Polarizer Sheet in Roll-to-Roll Process
Chi-Yuan Lee, Shuo-Jen Lee, Chwan-Hsen Chen, Lung-Jieh Yang, Xin-Wen Wang, Jyun-Ting Lin, Po-Yeng Chao, Shan-Yu Chen
February 21, 2023 (v1)
Keywords: polarizer sheet, R2R, self-made flexible three-in-one micro-sensor
The Roll-to-Roll (R2R) process refers to a high-efficiency, low-cost, continuous production method. The roll material used for processing is a flexible plastic or metal film. In many R2R processes, polarizing films are high-precision products with a high output value. In the production of conventional polarizers, product inspection will only be carried out after the production of the polarizing film is completed. The principal raw material of a polarizer sheet is a hydrophilic polymer, the properties of which may be influenced by water vapor, which degrades its quality. Whether or not the product is impacted can be ascertained by means of a quality inspection, but it must be performed after the process is finished. However, it is already too late when a defective product is detected: the production cost is increased, the schedule is influenced and the delivery date is delayed. The focus of this research was on environmental monitoring of the production drying process oven, but the comm... [more]
Fracture Interference and Refracturing of Horizontal Wells
Hai Lin, Yakai Tian, Zhenwei Sun, Fujian Zhou
February 21, 2023 (v1)
Keywords: finite element simulation, fluid filtration loss, refracturing, stress field, temporary plugging
Due to fracture interference, not all perforations can be fractured, resulting in 20% of fractures contributing to 80% of the total production. The extraction of oil and gas also reduces production, necessitating refracturing. In this study, the finite element method was used to simulate multiple fractures fracturing simultaneously and the stress field distribution was then extracted and applied to a new geological model. This paper explains the effect of stress around the horizontal wellbore on new fractures during the refracturing of old wells using a temporary plugging technique. The results show that initial breaking pressures are the same, but as fractures extend, inter-fracture interference increases, resulting in different fracture extension pressures and widths. The fracturing fluid is filtered into the reservoir matrix after fracturing, reducing formation stress. Compared with fracturing at the initial fracture site, reperforating fracturing has a lower fracture extension pres... [more]
Fabrication and Thermal Performance of 3D Copper-Mesh-Sintered Foam/Paraffin Phase Change Materials for Solar Thermal Energy Storage
Chao Chang, Guowei Chen, Fengyongkang Wu, Zhaoyang Han, Lilin Pei
February 21, 2023 (v1)
Subject: Materials
Keywords: copper foam, paraffin, phase change material, solar-thermal energy storage
Due to its large latent heat and high energy storage capacity, paraffin as one of the phase change materials (PCMs) has been widely applied in many energy-related applications in recent years. The current applications of paraffin, however, are limited by the low thermal conductivity and the leakage problem. To address these issues, we designed and fabricated form-stable composite PCMs by impregnating organic paraffin within graphite-coated copper foams. The graphite-coated copper foam was prepared by sintering multilayer copper meshes, and graphite nanoparticles were deposited on the surface of the porous copper foam. Graphite nanoparticles could directly absorb and convert solar energy into thermal energy, and the converted thermal energy was stored in the paraffin PCMs through phase change heat transfer. The graphite-coated copper foam not only effectively enhanced the thermal conductivity of paraffin PCMs, but also its porous structure and superhydrophobic surface prevented the para... [more]
Intelligent Prediction Model (IPM) of Foundation Pit Displacement Based on Extreme Learning Machine (ELM) and Its Application
Shangge Liu, Changzhong Sun, Hui Zhou, Yuanhai Wang
February 21, 2023 (v1)
Keywords: attribute reduction, average influence value algorithm, extreme learning machine, foundation pit deformation
In order to effectively predict the dynamic displacement and disaster, according to the analysis of the influencing parameters affecting the deformation of a subway foundation pit supported by piles (walls), the rough set attribute reduction method (RSARM) and the average influence value algorithm (AIVA) are used to simplify the influencing factors of foundation pit deformation. Those simplified factors are taken as the input of the ELM, with the output being the displacement of the foundation pit. Finally, the IPM of foundation pit displacement derived from the ELM is obtained, which is finally used for engineering practice. The results show that it is feasible to simplify the influencing factors of the deformation of the foundation pit by RSARM and AIVA. The proposed IPM of foundation pit displacement has high accuracy and good generalization ability, which can be used for the deformation prediction.
Production of Bivalent Subunit Vaccine for Porcine via 2A-Like Sequence in Baculovirus Expression Vector System
Ming-Hsiang Chen, Muhammed Muhsin Varikkodan, Ting-Hui Lin, Chien-Min Chiang, Indah Permata Sari, Ming-Der Perng, Tzong-Yuan Wu
February 21, 2023 (v1)
Subject: Biosystems
Keywords: adjuvant, baculovirus expression vector system, pig, porcine circovirus type 2, vaccine
Classical swine fever virus (CSFV) and porcine circovirus type 2 (PCV2) have caused severe diseases in swine populations worldwide. Here, a polycistronic baculovirus vector was developed to express a bivalent vaccine, consisting of the CSFV-E2 and PCV2-Cap protein, and an immunomodulator protein derived from the Flammulina velutipes, FVE-FIP, as well as the selection marker, green fluorescent protein. The simultaneous expression of the CSFV-E2 and PCV2-Cap protein was mediated by the 2A-like sequence derived from the Perina nuda virus (PnV), while the expression of the FVE-FIP was driven by the internal ribosome entry site (IRES) element derived from the Rhophalosipum padi virus (RhPV). The Western blot analysis result suggested that the CSFV-E2, PCV2-Cap, and FVE-FIP protein were successfully co-expressed by the infected Spodoptera frugiperda IPBL-Sf21 (Sf21) cell line. The extracted cell lysate containing all three recombinant proteins was administered to Balb/C mice with or without... [more]
An Unsupervised Clustering Method for Selection of the Fracturing Stage Design Based on the Gaussian Mixture Model
Xin Wang, Lifeng Yang, Meng Fan, Yushi Zou, Wenchao Wang
February 21, 2023 (v1)
Keywords: comprehensive reservoir quality, gaussian mixture model, multi-stage fracturing, the coupling evaluation
In order to further improve the efficiency and economic benefits of multi-stage fracturing of unconventional oil and gas horizontal wells, it is urgently needed to conduct comprehensive reservoir quality evaluation research on the whole horizontal well section. Firstly, based on logging data, focusing on reservoir quality and completion quality, and comprehensively considering key factors such as reservoir physical property indexes and fracability indexes, a subjective and objective coupled evaluation model of the entropy weight method (EWM) and the analytic hierarchy process (AHP) without bias is established to obtain the composite reservoir quality index. Then, unsupervised gaussian mixture model (GMM) clustering algorithms are used to classify the reservoir comprehensive quality index and finally four grades of fracturing stages are established. Taking shale oil well A and B of the Permian Lucaogou Formation in Jimsar Sag, Junggar Basin, as examples, the comprehensive reservoir qual... [more]
Performing Multi-Objective Optimization Alongside Dimension Reduction to Determine Number of Clusters
Melisa Mollaian, Gyula Dörgő, Ahmet Palazoglu
February 21, 2023 (v1)
Subject: Optimization
Keywords: data clustering, dimension reduction, multi-objective optimization, Pareto solution
One of the consequences of the widespread automation of manufacturing operations has been the proliferation and availability of historical databases that can be exploited by analytical methods to improve process understanding. Data science tools such as dimension reduction and clustering are among many such approaches that can aid in the identification of unique process features and patterns that can be associated with faulty states. However, determining the number of such states still requires significant engineering knowledge and insight. In this study, a new unsupervised method is proposed that reveals the number of classes in a data set. The method utilizes a variety of dimension reduction techniques to create projections of a data set and performs multiple clustering operations on the lower-dimensional data as well as the original data. The relevant internal clustering metrics are incorporated into a multi-objective optimization problem to determine the solutions that simultaneous... [more]
The Effects of Logistics Websites’ Technical Factors on the Optimization of Digital Marketing Strategies and Corporate Brand Name
Damianos P. Sakas, Dimitrios P. Reklitis, Panagiotis Trivellas, Costas Vassilakis, Marina C. Terzi
February 21, 2023 (v1)
Subject: Optimization
Keywords: advertising, Big Data, brand name, competitive advantage, digital marketing, logistics, predictive model, SEM, user engagement, web analytics
In a world overwhelmed with unstructured information, logistics companies increasingly depend on their websites to acquire new customers and maintain existing ones. Following this rationale, a series of technical elements may set the ground for differentiating one logistics website from another. Nevertheless, a suitable digital marketing strategy should be adopted in order to build competitive advantage. In this paper, the authors attempt to respond by implementing an innovative methodology building on web analytics and big data. The first phase of the research collects data for 180 days from 7 world-leading logistics companies. The second phase presents the statistical analysis of the gathered data, including regression, correlations, and descriptive statistics. Subsequently, Fuzzy Cognitive Mapping (FCM) was employed to illustrate the cause-and-effect links among the metrics in question. Finally, a predictive simulation model is developed to show the intercorrelation among the metric... [more]
Structural Characterization of Exopolysaccharide Produced by Leuconostoccitreum B-2 Cultured in Molasses Medium and Its Application in Set Yogurt
Lu Liang, Min Xu, Lei Pan, Zhijiang Zhou, Ye Han
February 21, 2023 (v1)
Subject: Materials
Keywords: exopolysaccharide, molasses, Optimization, set yogurt, structure
Sugarcane molasses is an agricultural by-product containing sucrose. In this study, the exopolysaccharide (M-EPS) produced by Leuconostoc citreum B-2 in molasses-based medium was characterized, optimized, and its application in set yogurt was investigated. The structure analysis, including gel permeation chromatography, Fourier transform infrared spectroscopy, and nuclear magnetic resonance, revealed that the M-EPS was a linear dextran composed of D-glucose units, which were linked by α-(1→6) glycosidic bonds with 19.3% α-(1→3) branches. The M-EPS showed a lower molecular weight than that produced from sucrose. The M-EPS was added into the set yogurt, and then the water holding capacity, pH, and microstructure of set yogurt were evaluated. Compared with the controls, the addition of M-EPS improved the water holding capacity and reduced the pH of set yogurt. Meanwhile, the structure of the three-dimensional network was also observed in the set yogurt containing M-EPS, indicating that M-... [more]
Microwave-Driven Electrodeless Ultraviolet Lamp Based on Coaxial Slot Radiator
Yuqing Huang, Nanya Zhong, Huacheng Zhu, Kama Huang
February 21, 2023 (v1)
Keywords: Drude model, electrodeless UV lamp, microwave plasma, miniaturization
Microwave-driven electrodeless ultraviolet (UV) lamps have the advantages of high efficiency and high power. However, the conventional microwave system is slightly oversized, which restricts the use of the lamp in a narrow space. A miniaturized microwave-driven electrodeless UV lamp based on a coaxial slot antenna was developed in this study. First, the structure of slots was optimized using a finite-difference time-domain algorithm such that high efficiency of radiated energy could be achieved. Second, a complex model based on the Drude model and the electromagnetic theory was established to simulate the interaction between the microwave and UV lamps. The efficiency and uniformity of the UV lamps were analyzed. Finally, an experimental system was built, and the computed results agreed well with the simulation results. The efficiency of the miniaturized microwave-driven electrodeless UV lamp reached 91.8%.
Integrating Triple Bottom Line in Sustainable Chemical Supplier Selection: A Compromise Decision-Making-Based Spherical Fuzzy Approach
Chia-Nan Wang, Chien-Chang Chou, Thanh-Tuan Dang, Hoang-Phu Nguyen, Ngoc-Ai-Thy Nguyen
February 21, 2023 (v1)
Subject: Materials
Keywords: chemical industry, CoCoSo, compromise solution, decision-making, SF-AHP, supplier selection, triple bottom line
As a consequence of increased awareness of environmental preservation and the associated rigorous regulations, the adoption of sustainable practices has become a crucial element for corporate organizations in regard to their supply chains. In the chemical industry, which is characterized by high risks, high pollution, and high efficiency, these characteristics can help businesses analyze their long-term development and sustainability. The goal of this research is to analyze and choose possible suppliers based on their sustainability performance in the chemical sector. A methodology based on multi-criteria decision making (MCDM) is proposed for this evaluation, using spherical fuzzy analytical hierarchy process (SF-AHP) and combined compromise solution (CoCoSo) methods, in which the novel spherical fuzzy sets theory is employed to present the ambiguous linguistic preferences of experts. In the first stage, an evaluation criteria system is identified through literature review and experts... [more]
Investigation of a Novel Deep Borehole Heat Exchanger for Building Heating and Cooling with Particular Reference to Heat Extraction and Storage
Jiaqi Zhang, Xinli Lu, Wei Zhang, Jiali Liu, Wen Yue, Feng Ma
February 21, 2023 (v1)
Keywords: deep borehole heat exchanger, geothermal energy, heat injection and storage, heating and cooling
Medium-depth and deep geothermal energy has been widely used because of its abundant resources and supply stability. Recently, attention has been given to the closed-loop heat extraction system using a deep borehole heat exchanger (DBHE), which enables geothermal energy to be harnessed almost everywhere. In this study, a check valve is adopted in a DBHE system in which the whole section of the well is used for heat extraction in winter during building heating and the upper part of the well is used for heat injection in summer during building cooling. The influence of injected water flowrates, water inlet temperatures, depths of the check valve and formation of thermal conductivities on the performance of this novel DBHE system has been investigated. It is found that heat injection through the upper part of the well in summer can improve the heat extraction rates to a certain extent during the heating season. In summer, the inlet temperature of water has a great influence on the heat in... [more]
A Pilot Model for the Treatment of Slaughterhouse Wastewater Using Zeolite or Psidium-Leaf Powder as a Natural Coagulant, Followed by Filtration with Rice Straw, in Comparison with an Inorganic Coagulant
Fatma Abouelenien, Yossra Ahmed Trabik, Mustafa Shukry, Mohamed El-Sharnouby, Samy Sayed, Ahmed Gaber, Nagham Rafeek Elsaidy
February 21, 2023 (v1)
Subject: Environment
Keywords: alum, green technology, Psidium guajava, rice straw, slaughterhouse wastewater, zeolite
Slaughterhouse wastewater (SHWW) is classified as industrial waste, which is exceptionally harmful to the environment due to its high content of biological oxygen demand (BOD), chemical oxygen demand (COD), and suspended solids, which result from high organic and nutrient loading. This study used a pilot system to treat SHWW from the Kafrelsheikh Governorate slaughterhouse, which includes a three-step process. It started with sedimentation, then coagulation and flocculation using different concentrations of each: natural zeolites (Z) and Psidium guajava-leaf powder (GLP) as green and environmentally friendly agents, and alum (A) as an inorganic coagulant. The final step was filtration with physically treated rice straw (RS). Each step was judged separately by measuring the removal percentages of each analyzed pollutant, and finally, the overall process was evaluated using the same method. A jar test was used to determine the best concentration of each coagulant used. The measured pollu... [more]
Development of CO2-Sensitive Viscoelastic Fracturing Fluid for Low Permeability Reservoirs: A Review
Allah Bakhsh, Liang Zhang, Huchao Wei, Azizullah Shaikh, Nasir Khan, Zeeshan Khan, Ren Shaoran
February 21, 2023 (v1)
Subject: Materials
Keywords: CO2-sensitive viscoelastic surfactant, fracturing fluid, low permeability reservoirs, rheology, worm-like micelles
There are economic and technical challenges to overcome when increasing resource recovery from low permeability reservoirs. For such reservoirs, the hydraulic fracturing plan with the development of clean and less expensive fracturing fluid plays a vital aspect in meeting the energy supply chain. Numerous recent published studies have indicated that research on worm-like micelles (WLMs) based on viscoelastic surfactant (VES) fluid has progressed substantially. This study looks at the development of CO2-sensitive viscoelastic fracturing fluid (CO2-SVFF), its applications, benefits, limitations, and drawbacks of conventional fracturing fluids. The switchable viscoelasticity of CO2-SVFF system signifies how reusing of this fluid is attained. Compared to conventional surfactants, the CO2-SVFF system can be switched to high viscosity (to fracture formation and transporting proppants) and low viscosity (easy removal after causing fracture). The effect of pH, conductivity, temperature, and rh... [more]
Physical Characterization of Material for the Development of Orthopedic Orthosis for Diabetic Foot
Karla Camila Lima de Souza, Anderson Marcio de Lima Batista, Eden Batista Duarte, Jonathan Elias Rodrigues Martins, Antônio Nadson Modesto Filho, José William Girão Dias, Diego Felix Dias, Morsyleide de Freitas Rosa, Raquel Martins de Freitas, Stela Mirla da Silva Felipe, Francisco Fleury Uchoa Santos Júnior, Vânia Marilande Ceccatto
February 21, 2023 (v1)
Subject: Materials
Keywords: diabetes, diabetic foot, Evapod, Hevea brasiliensis, latex, orthoses, Podadur, rubber tree, silicone
The diabetic foot is characterized by the loss of foot ulcerations and sensitivity. The use of orthopedic orthosis can prevent pathological changes in the diabetic foot. The objective of this study was to characterize materials used for producing orthopedic orthosis: silicone; pre-vulcanized latex of Hevea brasiliensis; Evapod, and Podadur. The Hevea brasiliensis latex material is widely indicated in the literature for biomedical purposes. Physical−mechanical properties were determined (properties of elastic deformation, resistance, durability, lightness, energy absorption, resistance to high temperatures, and chemical composition—ASTM International). In the tensile test, the latex reached 6.02 ± 0.33 MPa, having the best performance among the other materials. In the elastic module, the Podadur stood out, with 28.2 ± 0.89 MPa, compared to silicone with 0.42 ± 0.05 MPa. The most excellent Shore A hardness material was Podadur with 58%. As for the resilience, the Podadur presented a mini... [more]
Equilibrium Biosorption of Zn2+ and Ni2+ Ions from Monometallic and Bimetallic Solutions by Crab Shell Biomass
Liliana Morales-Barrera, Eliseo Cristiani-Urbina
February 21, 2023 (v1)
Subject: Biosystems
Keywords: biosorption, CLSM, crab shell, DRIFTS, mono-component isotherm, multicomponent isotherm, nickel, SEM-EDX, XRF, zinc
This work explored the technical feasibility of using crab shell (CS) as a promising, low-cost biosorbent to individually and simultaneously remove Zn2+ and Ni2+ from aqueous solutions. It was found that in both monometallic and bimetallic systems, Zn2+ and Ni2+ biosorption by CS was strongly dependent on the solution pH, with the optimum biosorption occurring at a pH of 6.0 for both heavy metals. The obtained isotherms for Zn2+ and Ni2+ biosorption onto CS in monometallic and bimetallic systems demonstrated that CS has a higher affinity for Zn2+ than for Ni2+. The experimental equilibrium data for the bimetallic system revealed that when one heavy metal is present in the system, there is a decrease in the equilibrium biosorption capacity for the other heavy metal; therefore, the combined action of Zn2+ and Ni2+ was antagonistic. The Sips and Redlich−Peterson isotherm models best fitted the equilibrium biosorption data for Zn2+ and Ni2+ in the monometallic systems, while the modified S... [more]
Designing Robust Biotechnological Processes Regarding Variabilities Using Multi-Objective Optimization Applied to a Biopharmaceutical Seed Train Design
Tanja Hernández Rodríguez, Anton Sekulic, Markus Lange-Hegermann, Björn Frahm
February 21, 2023 (v1)
Keywords: Bayes optimization, cell culture, Gaussian processes, multi-objective, Pareto optimization, seed train
Development and optimization of biopharmaceutical production processes with cell cultures is cost- and time-consuming and often performed rather empirically. Efficient optimization of multiple objectives such as process time, viable cell density, number of operating steps & cultivation scales, required medium, amount of product as well as product quality depicts a promising approach. This contribution presents a workflow which couples uncertainty-based upstream simulation and Bayes optimization using Gaussian processes. Its application is demonstrated in a simulation case study for a relevant industrial task in process development, the design of a robust cell culture expansion process (seed train), meaning that despite uncertainties and variabilities concerning cell growth, low variations of viable cell density during the seed train are obtained. Compared to a non-optimized reference seed train, the optimized process showed much lower deviation rates regarding viable cell densities (&l... [more]
Polyethylenimine/cGAMP Nanocomplexes for STING-Mediated Cancer Immunotherapy: Formulation and Characterization Using Orthogonal Techniques
Marija Petrovic, Gerrit Borchard, Olivier Jordan
February 21, 2023 (v1)
Subject: Biosystems
Keywords: asymmetric flow field flow fractionation AF4, cGAMP, dynamic light scattering DLS, nano quality control, nanomedicine regulations, nanoparticle tracking analysis NTA, polyethyleneimine
Cyclic GMP-AMP (cGAMP) has lately been extensively investigated in cancer immunotherapy due its activation of the innate immunity stimulation of interferon genes (STING) pathway within antigen presenting cells (APC) leading to an increase in tumor specific CD8+ T cells. As negatively charged dinucleotides are prone to enzymatic degradation before being taken up by APC, there is a need for an appropriate carrier. Therefore, polyethylenimine (PEI), a gold standard for oligonucleotide delivery, was selected. Molecular weight, type of PEI and N/P ratio between PEI/cGAMP were investigated in terms of toxicity, efficacy and physicochemical properties of the nanocomplexes (NCs) such as size, zeta potential and shape. Due to lack of nano-medicine regulations and the need for a case-by case assessment, here we examine these parameters by several orthogonal methods, such as dynamic light scattering (DLS), nanoparticle tracking analysis (NTA) and online asymmetric flow field flow fractionation (A... [more]
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