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Processes, Volume 8, Issue 7 (July 2020) – 56 articles

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Open AccessCommunication
Oxidant–Antioxidant Status in Canine Multicentric Lymphoma and Primary Cutaneous Mastocytoma
Processes 2020, 8(7), 802; https://doi.org/10.3390/pr8070802 (registering DOI) - 08 Jul 2020
Abstract
Oxidative stress is a prominent event in several acute and chronic diseases including neoplasia. Although its direct involvement in carcinogenesis still remains to be clearly defined, a deeper knowledge of oxidative stress in oncologic patients could help to monitor their clinical outcome and [...] Read more.
Oxidative stress is a prominent event in several acute and chronic diseases including neoplasia. Although its direct involvement in carcinogenesis still remains to be clearly defined, a deeper knowledge of oxidative stress in oncologic patients could help to monitor their clinical outcome and to develop new therapeutic approaches. Therefore, the present study was undertaken to explore redox status in blood of neoplastic dogs affected either by multicentric lymphoma or by primary cutaneous mastocytoma. Superoxide anion (O2 •−), nitric oxide (NO) and hydroperoxides (ROOH) were measured. Detoxifying enzyme superoxide dismutase (SOD) and total non-enzymatic antioxidant capacity (ferric reducing-antioxidant power (FRAP)) were assessed. The oxidative stress index (OSi) both for enzymatic (OSiE) and non-enzymatic (OSiNE) scavengers were evaluated. Both pathologies, showed a reduced NO generation, while O2 •− levels were decreased only in mastocytoma. The oxidative stress indexes showed a significant decrease in mastocytoma patients, only for OSiE. Full article
(This article belongs to the Special Issue Advances of Redox Status in Disease)
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Open AccessArticle
Evaluation of Immobilization of Selected Peat-Isolated Yeast Strains of the Species Candida albicans and Candida subhashii on the Surface of Artificial Support Materials Used for Biotrickling Filtration
Processes 2020, 8(7), 801; https://doi.org/10.3390/pr8070801 (registering DOI) - 08 Jul 2020
Abstract
The paper describes the process of n-butanol abatement by unicellular fungi, able to deplete n-butanol content in gas, by using n-butanol as source of carbon. Isolated and identified fungi species Candida albicans and Candida subhashii were subjected to a viability process [...] Read more.
The paper describes the process of n-butanol abatement by unicellular fungi, able to deplete n-butanol content in gas, by using n-butanol as source of carbon. Isolated and identified fungi species Candida albicans and Candida subhashii were subjected to a viability process via assimilation of carbon from hydrophilic and hydrophobic compounds. The isolates, which exhibited the ability to assimilate carbon, were immobilized on four different types of artificial support materials used for biotrickling filtration. Application of optical microscopy, flow cytometry and the tests employing propidium iodide and annexin V revealed viability of the fungi isolated on support materials’ surfaces at the average level of 95%. The proposed method of immobilization and its evaluation appeared to be effective, cheap and fast. Based on performed comparative analyses, it was shown that polyurethane foam and Bialecki rings (25 × 25) could be attractive support materials in biotrickling filtration. Full article
(This article belongs to the Section Green Processes)
Open AccessFeature PaperArticle
Heavy Oil Hydrocarbons and Kerogen Destruction of Carbonate–Siliceous Domanic Shale Rock in Sub- and Supercritical Water
Processes 2020, 8(7), 800; https://doi.org/10.3390/pr8070800 (registering DOI) - 08 Jul 2020
Abstract
This paper discusses the results of the influences of subcritical (T = 320 °C; P = 17 MPa) and supercritical water (T = 374 °C; P = 24.6 MPa) on the yield and composition of oil hydrocarbons generated from carbonaceous–siliceous Domanic shale rocks [...] Read more.
This paper discusses the results of the influences of subcritical (T = 320 °C; P = 17 MPa) and supercritical water (T = 374 °C; P = 24.6 MPa) on the yield and composition of oil hydrocarbons generated from carbonaceous–siliceous Domanic shale rocks with total organic content (Corg) of 7.07%. It was revealed that the treatment of the given shale rock in sub- and supercritical water environments resulted in the decrease of oil content due to the intensive gas formation. The content of light hydrocarbon fractions (saturated and aromatic hydrocarbons) increased at 320 °C from 33.98 to 39.63%, while at 374 °C to 48.24%. Moreover, the content of resins decreased by almost twice. Insoluble coke-like compounds such as carbene–carboids were formed due to decomposition of kerogen after supercritical water treatment. Analysis of oil hydrocarbons with FTIR method revealed a significant number of oxygen-containing compounds, which are the hydrogenolysis products of structural fragments formed after destruction of kerogen and high-molecular components of oil. The gas chromatography–mass spectroscopy (GC–MS) method was applied to present the changes in the composition of mono- and dibenzothiophenes, which indicate conversion of heavy components into lighter aromatic hydrocarbons. The specific features of transforming trace elements in rock samples, asphaltenes, and carbene–carboids were observed by using the isotopic mass-spectrometry method. Full article
(This article belongs to the Special Issue Heavy Oils Conversion Processes)
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Open AccessFeature PaperReview
Recent Insights into Lignocellulosic Biomass Pyrolysis: A Critical Review on Pretreatment, Characterization, and Products Upgrading
Processes 2020, 8(7), 799; https://doi.org/10.3390/pr8070799 (registering DOI) - 08 Jul 2020
Abstract
Pyrolysis process has been considered to be an efficient approach for valorization of lignocellulosic biomass into bio-oil and value-added chemicals. Bio-oil refers to biomass pyrolysis liquid, which contains alkanes, aromatic compounds, phenol derivatives, and small amounts of ketone, ester, ether, amine, and alcohol. [...] Read more.
Pyrolysis process has been considered to be an efficient approach for valorization of lignocellulosic biomass into bio-oil and value-added chemicals. Bio-oil refers to biomass pyrolysis liquid, which contains alkanes, aromatic compounds, phenol derivatives, and small amounts of ketone, ester, ether, amine, and alcohol. Lignocellulosic biomass is a renewable and sustainable energy resource for carbon that is readily available in the environment. This review article provides an outline of the pyrolysis process including pretreatment of biomass, pyrolysis mechanism, and process products upgrading. The pretreatment processes for biomass are reviewed including physical and chemical processes. In addition, the gaps in research and recommendations for improving the pretreatment processes are highlighted. Furthermore, the effect of feedstock characterization, operating parameters, and types of biomass on the performance of the pyrolysis process are explained. Recent progress in the identification of the mechanism of the pyrolysis process is addressed with some recommendations for future work. In addition, the article critically provides insight into process upgrading via several approaches specifically using catalytic upgrading. In spite of the current catalytic achievements of catalytic pyrolysis for providing high-quality bio-oil, the production yield has simultaneously dropped. This article explains the current drawbacks of catalytic approaches while suggesting alternative methodologies that could possibly improve the deoxygenation of bio-oil while maintaining high production yield. Full article
(This article belongs to the Special Issue Feature Review Papers)
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Open AccessFeature PaperArticle
European Union Legislation Overview about Used Vegetable Oils Recycling: The Spanish and Italian Case Studies
Processes 2020, 8(7), 798; https://doi.org/10.3390/pr8070798 (registering DOI) - 08 Jul 2020
Abstract
The employment of used vegetable oils (UVOs) as raw materials in key sectors as energy production or bio-lubricant synthesis represents one of the most relevant priorities in the European Union (EU) normative context. In many countries, the development of new production processes based [...] Read more.
The employment of used vegetable oils (UVOs) as raw materials in key sectors as energy production or bio-lubricant synthesis represents one of the most relevant priorities in the European Union (EU) normative context. In many countries, the development of new production processes based on the circular economy model, as well as the definition of future energy and production targets, involve the utilization of wastes as raw material. In this context, the main currently applied EU regulations are presented and discussed. As in the EU, the general legislative process consists of the definition in each State Member of specific legislation, which transposes the EU indications. Two relevant countries are herein considered: Italy and Spain. Through the analysis of the conditions required in both countries for UVOs’ collection, disposal, storage, and recycling, a wide panorama of the current situation is provided. Full article
(This article belongs to the Special Issue Recycling of Waste Oils: Technology and Application)
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Open AccessArticle
Optimizing the Processing Factor and Formulation of Oat-Based Cookie Dough for Enhancement in Stickiness and Moisture Content Using Response Surface Methodology and Superimposition
Processes 2020, 8(7), 797; https://doi.org/10.3390/pr8070797 (registering DOI) - 08 Jul 2020
Abstract
Despite the utilization of dusting flour and oil to reduce dough stickiness during the production process in food industry, they do not effectively help in eliminating the problem. Stickiness remains the bane of the production of bakery and confectionery products, including cookies. In [...] Read more.
Despite the utilization of dusting flour and oil to reduce dough stickiness during the production process in food industry, they do not effectively help in eliminating the problem. Stickiness remains the bane of the production of bakery and confectionery products, including cookies. In addition, the high moisture content of cookie dough is unduly important to obtain a high breaking and compression strengths (cookies with high breaking tolerance). This study was conducted in light of insufficient research hitherto undertaken on the utilization of response surface methodology and superimposition to enhance the stickiness and moisture content of quick oat-based cookie dough. The study aims at optimizating, validating and superimposing the best combination of factors, to produce the lowest stickiness and highest moisture content in cookie dough. In addition, the effect of flour content and resting time on the stickiness and moisture content of cookie dough was also investigated, and microstructure analysis conducted. The central composite design (CCD) technique was employed and 39 runs were generated by CCD based on two factors with five levels, which comprised flour content (50, 55, 60, 65, and 70%), resting time (10, 20, 30, 40, and 50 min) and three replications. Results from ANOVA showed that all factors were statistically significant at p < 0.05. Flour content between 56% and 62%, and resting time within 27 and 50 min, resulted in dough with high stickiness. High-region moisture content was observed for flour content between 60% and 70%, and within 10 and 15 min of resting time. The optimized values for flour content (V1) = 67% and resting time (V2) = 10 min. The predicted model (regression coefficient model) was found to be accurate in predicting the optimum value of factors. The experimental validation showed the average relative deviation for stickiness and moisture content was 8.54% and 1.44%, respectively. The superimposition of the contour plots was successfully developed to identify the optimum region for the lowest stickiness and highest moisture content which were at 67–70% flour content and 10–15 min resting time. Full article
(This article belongs to the Section Food Processes)
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Open AccessArticle
Experimental Studies on a New Controller Design and Implementation in Direct Methanol Fuel Cell
Processes 2020, 8(7), 796; https://doi.org/10.3390/pr8070796 (registering DOI) - 08 Jul 2020
Viewed by 99
Abstract
A dynamic model of a Direct Methanol Fuel Cell is developed in the MATLAB platform. A newly proposed Coefficient Diagram based Proportional Integral Controller (CD-PIC) is designed and its parameters are calculated. The newly designed CD-PIC is implemented in a real time Direct [...] Read more.
A dynamic model of a Direct Methanol Fuel Cell is developed in the MATLAB platform. A newly proposed Coefficient Diagram based Proportional Integral Controller (CD-PIC) is designed and its parameters are calculated. The newly designed CD-PIC is implemented in a real time Direct Methanol Fuel Cell (DMFC) experimental setup. Performances in real time operation of the Direct Methanol Fuel Cell (DMFC) are evaluated. The performance of CD-PIC is obtained under tracking of set point changes. In order to evaluate the CD-PIC performances, most popular tuning rules based Conventional PI Controllers (C-PIC) are also designed and analyzed. Set point tracking is carried out for the step changes of ±10% and ±15% at two different operational points. The controller performances are analyzed in terms of Controller Performance Measuring (CPM) indices. The said performance measures indicate that the proposed CD-PIC gives the superior performances for set point changes and found very much robust in controlling DMFC. Full article
(This article belongs to the Special Issue Applications of Process Control in Energy Systems)
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Open AccessArticle
Investigation of Plume Offset Characteristics in Bubble Columns by Euler–Euler Simulation
Processes 2020, 8(7), 795; https://doi.org/10.3390/pr8070795 - 07 Jul 2020
Viewed by 121
Abstract
Based on low-cost and easy to enlarge, the bubble column device has been widely concerned in chemical industry. This paper focuses on bubble plumes in laboratory-scale three-dimensional rectangular air-water columns. Static behavior has been investigated in many experiments and simulations, and our present [...] Read more.
Based on low-cost and easy to enlarge, the bubble column device has been widely concerned in chemical industry. This paper focuses on bubble plumes in laboratory-scale three-dimensional rectangular air-water columns. Static behavior has been investigated in many experiments and simulations, and our present investigations consider the dynamic behavior of bubble plume offset in three dimensions. The investigations are conducted with a set of closure models by the Euler–Euler approach, and subsequently, literature data for rectangular bubble columns are analyzed for comparison purposes. Moreover, the transient evolution characteristics of the bubble plume in the bubble column and the gas phase distribution in sections are introduced, and the offset characteristics and the oscillation period of the plume are analyzed. In addition, the distributions of the vector diagram of velocity and vortex intensity in the domain are given. The effects of different fluxes and column aspect ratios on bubble plumes are studied, and the offset and plume oscillation period (POP) characteristics of bubbles are examined. The investigations reveal quantitative correlations of operating conditions (gas volume flux) and aspect ratios that have not been reported so far, and the simulated and experimental POP results agree well. An interesting phenomenon is that POP does not occur under conditions of a high flux and aspect ratio, and the corresponding prediction values for the conditions with and without POP are given as well. The results reported in this paper may open up a new way for further study of the mass transfer of bubble plumes and development of chemical equipment. Full article
(This article belongs to the Special Issue Chemical Process Design, Simulation and Optimization)
Open AccessArticle
Mode-Based Analysis and Optimal Operation of MSF Desalination System
Processes 2020, 8(7), 794; https://doi.org/10.3390/pr8070794 - 07 Jul 2020
Viewed by 142
Abstract
Multi-stage flash (MSF) desalination plays an important role in achieving large-scale fresh water driven by thermal energy. In this paper, based on first-principle modeling of a typical multi-stage flash desalination system, the effects of different operational parameters on system performance and operational optimization [...] Read more.
Multi-stage flash (MSF) desalination plays an important role in achieving large-scale fresh water driven by thermal energy. In this paper, based on first-principle modeling of a typical multi-stage flash desalination system, the effects of different operational parameters on system performance and operational optimization for cost saving were extensively studied. Firstly, the modelled desalination system was divided into flash chamber modules, brine heater modules, mixed modules and split modules, and based on energy and mass conservation laws the equations were formulated and put together to describe the whole process model. Then, with physical parameter calculation the whole process was simulated and analyzed on the platform of MATLAB, and the water production performance effected by operational parameters such as the feed temperature of seawater, the recycle brine from the discharge section, steam temperature and flowrate of recycled brine were discussed and analyzed. Then, the optimal operation to achieve maximize GOR (gained output ratio) with fixed freshwater demand was considered and performed, and thus the optimal flowrate of recycled brine, steam temperature, and seawater output flowrate from rejection section were obtained based on the established model. Finally, considering that minimizing the daily operational cost is a more rational objective, the operational cost equations were formulated and the optimal problem to minimize the daily operational cost was solved and the optimal manipulated variables at different hours were obtained. The study results can be used for guideline of real time optimization of the MSF system. Full article
(This article belongs to the Special Issue Design, Control and Optimization of Desalination Processes)
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Open AccessFeature PaperReview
Liquid Marbles as Miniature Reactors for Chemical and Biological Applications
Processes 2020, 8(7), 793; https://doi.org/10.3390/pr8070793 - 07 Jul 2020
Viewed by 135
Abstract
The need for miniaturised reaction systems has led to the development of various microreactor platforms, such as droplet-based microreactors. However, these microreactors possess inherent drawbacks, such as rapid evaporation and difficult handling, that limit their use in practical applications. Liquid marbles are droplets [...] Read more.
The need for miniaturised reaction systems has led to the development of various microreactor platforms, such as droplet-based microreactors. However, these microreactors possess inherent drawbacks, such as rapid evaporation and difficult handling, that limit their use in practical applications. Liquid marbles are droplets covered with hydrophobic particles and are a potential platform that can overcome the weaknesses of bare droplets. The coating particles completely isolate the interior liquids from the surrounding environment, thus conveniently encapsulating the reactions. Great efforts have been made over the past decade to demonstrate the feasibility of liquid marble-based microreactors for chemical and biological applications. This review systemically summarises state-of-the-art implementations of liquid marbles as microreactors. This paper also discusses the various aspects of liquid marble-based microreactors, such as the formation, manipulation, and future perspectives. Full article
(This article belongs to the Special Issue Liquid Marble Manipulation and Applications)
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Open AccessArticle
Optimization of Electrolysis Parameters for Green Sanitation Chemicals Production Using Response Surface Methodology
Processes 2020, 8(7), 792; https://doi.org/10.3390/pr8070792 - 06 Jul 2020
Viewed by 192
Abstract
Electrolyzed water (EW) shows great potential as a green and economical sanitation solution for the food industry. However, only limited studies have investigated the optimum electrolysis parameters and the bactericidal effect of acidic electrolyzed water (AcEW) and alkaline electrolyzed water (AlEW). Here, the [...] Read more.
Electrolyzed water (EW) shows great potential as a green and economical sanitation solution for the food industry. However, only limited studies have investigated the optimum electrolysis parameters and the bactericidal effect of acidic electrolyzed water (AcEW) and alkaline electrolyzed water (AlEW). Here, the Box–Behnken experimental design was used to identify the optimum parameters. The tests were conducted with different types of electrodes, electrical voltages, electrolysis times, and NaCl concentrations. There were no obvious differences observed in the physico-chemical properties of EW when different electrodes were used. However, stainless steel was chosen as it meets most of the selection criteria. The best-optimized conditions for AcEW were at 11.39 V, 0.65 wt.% NaCl, and 7.23 min, while the best-optimized conditions for AlEW were at 10.32 V, 0.6 wt.% NaCl, and 7.49 min. The performance of the optimum EW (AcEW and AlEW) compared with commercial cleaning detergents for the food industry was then evaluated. The bactericidal activity of AcEW and AlEW was examined against Escherichia coli ATCC 10536 at different temperatures (30 °C and 50 °C) for 30 s. The results show that both AcEW and AlEW have the ability to reduce the Escherichia coli to non-detectable levels (less than 2 log CFU/mL). Full article
(This article belongs to the Special Issue Synergies in Combined Development of Processes and Models)
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Open AccessFeature PaperArticle
Mathematical Modeling and Stability Analysis of a Two-Phase Biosystem
Processes 2020, 8(7), 791; https://doi.org/10.3390/pr8070791 - 06 Jul 2020
Viewed by 131
Abstract
We propose a new mathematical model describing a biotechnological process of simultaneous production of hydrogen and methane by anaerobic digestion. The process is carried out in two connected continuously stirred bioreactors. The proposed model is developed by adapting and reducing the well known [...] Read more.
We propose a new mathematical model describing a biotechnological process of simultaneous production of hydrogen and methane by anaerobic digestion. The process is carried out in two connected continuously stirred bioreactors. The proposed model is developed by adapting and reducing the well known Anaerobic Digester Model No 1 (ADM1). Mathematical analysis of the model is carried out, involving existence and uniqueness of positive and uniformly bounded solutions, computation of equilibrium points, investigation of their local stability with respect to practically important input parameters. Existence of maxima of the input–output static characteristics with respect to hydrogen and methane is established. Numerical simulations using a specially elaborated web-based software environment are presented to demonstrate the dynamic behavior of the model solutions. Full article
(This article belongs to the Special Issue Modelling and Optimal Design of Complex Biological Systems)
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Open AccessFeature PaperArticle
Development of Indicator of Data Sufficiency for Feature-based Early Time Series Classification with Applications of Bearing Fault Diagnosis
Processes 2020, 8(7), 790; https://doi.org/10.3390/pr8070790 - 06 Jul 2020
Viewed by 138
Abstract
Diagnosis of bearing faults is crucial in various industries. Time series classification (TSC) assigns each time series to one of a set of pre-defined classes, such as normal and fault, and has been regarded as an appropriate approach for bearing fault diagnosis. Considering [...] Read more.
Diagnosis of bearing faults is crucial in various industries. Time series classification (TSC) assigns each time series to one of a set of pre-defined classes, such as normal and fault, and has been regarded as an appropriate approach for bearing fault diagnosis. Considering late and inaccurate fault diagnosis may have a significant impact on maintenance costs, it is important to classify bearing signals as early and accurately as possible. TSC, however, has a major limitation, which is that a time series cannot be classified until the entire series is collected, implying that a fault cannot be diagnosed using TSC in advance. Therefore, it is important to classify a partially collected time series for early time series classification (ESTC), which is a TSC that considers both accuracy and earliness. Feature-based TSCs can handle this, but the problem is to determine whether a partially collected time series is enough for a decision that is still unsolved. Motivated by this, we propose an indicator of data sufficiency to determine whether a feature-based fault detection classifier can start classifying partially collected signals in order to diagnose bearing faults as early and accurately as possible. The indicator is trained based on the cosine similarity between signals that were collected fully and partially as input to the classifier. In addition, a parameter setting method for efficiently training the indicator is also proposed. The results of experiments using four benchmark datasets verified that the proposed indicator increased both accuracy and earliness compared with the previous time series classification method and general time series classification. Full article
Open AccessArticle
Prediction of Cutting Material Durability by T = f(vc) Dependence for Turning Processes
Processes 2020, 8(7), 789; https://doi.org/10.3390/pr8070789 - 06 Jul 2020
Viewed by 134
Abstract
This article is focused on the prediction of cutting material durability by Taylor’s model. To create predictive models of the durability of cutting materials in the turning process, tools made of high-speed steel, sintered carbide without coating and with Titanium nitride (TiN) coating, [...] Read more.
This article is focused on the prediction of cutting material durability by Taylor’s model. To create predictive models of the durability of cutting materials in the turning process, tools made of high-speed steel, sintered carbide without coating and with Titanium nitride (TiN) coating, cutting ceramics without coating and with TiN coating were applied. The experimental part was performed on reference material C45 using conventional lathe—type of machine SU50A and computer numerical control machine—CNC lathe Leadwell T-5 in accordance with International Organization for Standardization—ISO 3685. Implementation of the least-squares method and processing of regression analysis made predictions of cutting tool behaviour in the turning process. Using the method of regression analysis, a correlation index of 93.5% was obtained, indicating the functional dependence of the predicted relationship. Full article
(This article belongs to the Special Issue Redesign Processes in the Age of the Fourth Industrial Revolution)
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Open AccessReview
Spray Drying for the Preparation of Nanoparticle-Based Drug Formulations as Dry Powders for Inhalation
Processes 2020, 8(7), 788; https://doi.org/10.3390/pr8070788 - 06 Jul 2020
Viewed by 215
Abstract
Nanoparticle-based therapeutics have been used in pulmonary formulations to enhance delivery of poorly water-soluble drugs, protect drugs against degradation and achieve modified release and drug targeting. This review focuses on the use of spray drying as a solidification technique to produce microparticles containing [...] Read more.
Nanoparticle-based therapeutics have been used in pulmonary formulations to enhance delivery of poorly water-soluble drugs, protect drugs against degradation and achieve modified release and drug targeting. This review focuses on the use of spray drying as a solidification technique to produce microparticles containing nanoparticles (i.e., nanoparticle (NP) agglomerates) with suitable properties as dry powders for inhalation. The review covers the general aspects of pulmonary drug delivery with emphasis on nanoparticle-based dry powders for inhalation and the principles of spray drying as a method for the conversion of nanosuspensions to microparticles. The production and therapeutic applications of the following types of NP agglomerates are presented: nanoporous microparticles, nanocrystalline agglomerates, lipid-based and polymeric formulations. The use of alternative spray-drying techniques, namely nano spray drying, and supercritical CO2-assisted spray drying is also discussed as a way to produce inhalable NP agglomerates. Full article
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Open AccessArticle
Evaluation of the Interactive Effect Pretreatment Parameters via Three Types of Microwave-Assisted Pretreatment and Enzymatic Hydrolysis on Sugar Yield
Processes 2020, 8(7), 787; https://doi.org/10.3390/pr8070787 - 06 Jul 2020
Viewed by 211
Abstract
This study aims to evaluate the sugar yield from enzymatic hydrolysis and the interactive effect pretreatment parameters of microwave-assisted pretreatment on glucose and xylose. Three types of microwave-assisted pretreatments of sago palm bark (SPB) were conducted for enzymatic hydrolysis, namely: microwave-sulphuric acid pretreatment [...] Read more.
This study aims to evaluate the sugar yield from enzymatic hydrolysis and the interactive effect pretreatment parameters of microwave-assisted pretreatment on glucose and xylose. Three types of microwave-assisted pretreatments of sago palm bark (SPB) were conducted for enzymatic hydrolysis, namely: microwave-sulphuric acid pretreatment (MSA), microwave-sodium hydroxide pretreatment (MSH), and microwave-sodium bicarbonate (MSB). The experimental design was done using a response surface methodology (RSM) and Box–Behenken Design (BBD). The pretreatment parameters ranged from 5–15% solid loading (SL), 5–15 min of exposure time (ET), and 80–800 W of microwave power (MP). The results indicated that the maximum total reducing sugar was 386 mg/g, obtained by MSA pretreatment. The results also illustrated that the higher glucose yield, 44.3 mg/g, was found using MSH pretreatment, while the higher xylose yield, 43.1 mg/g, resulted from MSA pretreatment. The pretreatment parameters MP, ET, and SL showed different patterns of influence on glucose and xylose yield via enzymatic hydrolysis for MSA, MSH, and MSB pretreatments. The analyses of the interactive effect of the pretreatment parameters MP, ET, and SL on the glucose yield from SPB showed that it increased with the high MP and longer ET, but this was limited by low SL values. However, the analysis of the interactive effect of the pretreatment parameters on xylose yields revealed that MP had the most influence on the xylose yield for MSA, MSH, and MSB pretreatments. Full article
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Open AccessReview
Potential of Jatropha curcas L. as Biodiesel Feedstock in Malaysia: A Concise Review
Processes 2020, 8(7), 786; https://doi.org/10.3390/pr8070786 - 06 Jul 2020
Viewed by 168
Abstract
Fluctuation in fossil fuel prices and the increasing awareness of environmental degradation have prompted the search for alternatives from renewable energy sources. Biodiesel is the most efficient alternative to fossil fuel substitution because it can be properly modified for current diesel engines. It [...] Read more.
Fluctuation in fossil fuel prices and the increasing awareness of environmental degradation have prompted the search for alternatives from renewable energy sources. Biodiesel is the most efficient alternative to fossil fuel substitution because it can be properly modified for current diesel engines. It is a vegetable oil-based fuel with similar properties to petroleum diesel. Generally, biodiesel is a non-toxic, biodegradable, and highly efficient alternative for fossil fuel substitution. In Malaysia, oil palm is considered as the most valuable commodity crop and gives a high economic return to the country. However, the ethical challenge of food or fuel makes palm oil not an ideal feedstock for biodiesel production. Therefore, attention is shifted to non-edible feedstock like Jatropha curcas Linnaeus (Jatropha curcas L.). It is an inedible oil-bearing crop that can be processed into biodiesel. It has a high-seed yield that could be continually produced for up to 50 years. Furthermore, its utilization will have zero impact on food sources since the oil is poisonous for human and animal consumption. However, Jatropha biodiesel is still in its preliminary phase compared to palm oil-based biodiesel in Malaysia due to a lack of research and development. Therefore, this paper emphasizes the potential of Jatropha curcas as an eco-friendly biodiesel feedstock to promote socio-economic development and meet significantly growing energy demands even though the challenges for its implementation as a national biodiesel program might be longer. Full article
(This article belongs to the Special Issue Biotechnology for Sustainability and Social Well Being)
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Open AccessArticle
Capacitated Lot-Sizing Problem with Sequence-Dependent Setup, Setup Carryover and Setup Crossover
Processes 2020, 8(7), 785; https://doi.org/10.3390/pr8070785 - 05 Jul 2020
Viewed by 210
Abstract
Since setup operations have significant impacts on production environments, the capacitated lot-sizing problem considering arbitrary length of setup times helps to develop flexible and efficient production plans. This study discusses a capacitated lot-sizing problem with sequence-dependent setup, setup carryover and setup crossover. A [...] Read more.
Since setup operations have significant impacts on production environments, the capacitated lot-sizing problem considering arbitrary length of setup times helps to develop flexible and efficient production plans. This study discusses a capacitated lot-sizing problem with sequence-dependent setup, setup carryover and setup crossover. A new mixed integer programming formulation is proposed. The formulation is based on three building blocks: the facility location extended formulation; the setup variables with indices for the starting and the completion time periods; and exponential number of generalized subtour elimination constraints (GSECs). A separation routine is adopted to generate the violated GSECs. Computational experiments show that the proposed formulation outperforms models from the literature. Full article
(This article belongs to the Special Issue Advances in Sustainable Supply Chains)
Open AccessArticle
A Novel Bearing Fault Diagnosis Method Based on GL-mRMR-SVM
Processes 2020, 8(7), 784; https://doi.org/10.3390/pr8070784 - 05 Jul 2020
Viewed by 225
Abstract
A convolutional neural network (CNN) has been used to successfully realize end-to-end bearing fault diagnosis due to its powerful feature extraction ability. However, the CNN is prone to focus on local information, ignoring the relationship between the whole and the part of the [...] Read more.
A convolutional neural network (CNN) has been used to successfully realize end-to-end bearing fault diagnosis due to its powerful feature extraction ability. However, the CNN is prone to focus on local information, ignoring the relationship between the whole and the part of the signal due to its unique structure. In addition, it extracts some fault features with poor robustness under noisy environment. A novel diagnosis model based on feature fusion and feature selection, GL-mRMR-SVM, is proposed to address this problem in this paper. First, the model combines the global features in the time-domain and frequency-domain of the raw data with the local features extracted by CNN to make full use of the signal information and overcome the weakness of traditional CNNs neglecting the overall signal. Then, the max-relevance min-redundancy (mRMR) algorithm is used to automatically extract the discriminative features from the fused features without any prior knowledge. Finally, the extracted discriminative features are input into the SVM for training and output the fault recognition results. The proposed GL-mRMR-SVM model was evaluated through experiments on bearing data of Case Western Reserve University (CWRU) and CUT-2 platform. The experimental results show that the proposed method is more effective than other intelligent diagnosis methods. Full article
(This article belongs to the Section Computational Methods)
Open AccessArticle
Dust Suppression Analysis of a New Spiral Hopper Using CFD-DEM Simulations and Experiments
Processes 2020, 8(7), 783; https://doi.org/10.3390/pr8070783 - 05 Jul 2020
Viewed by 170
Abstract
A new dust suppression hopper with a spiral guide plate embedded in the conventional hopper is proposed for the dust suppression of hopper transfer processes in this article. The Computational Fluid Dynamics-Discrete Element Method (CFD-DEM) coupling numerical method is used to investigate the [...] Read more.
A new dust suppression hopper with a spiral guide plate embedded in the conventional hopper is proposed for the dust suppression of hopper transfer processes in this article. The Computational Fluid Dynamics-Discrete Element Method (CFD-DEM) coupling numerical method is used to investigate the particle motion and flow field distribution of the hopper transfer process. The experiment is undertaken to determine dust suppression performance. The results show that the maximum particle velocity for the spiral hopper is dropped by 1.6 m/s compared to the conventional hopper, which means the collision of the particles and the spiral hopper is weakened. The axial airflow velocity of the spiral is reduced. In addition, the maximum dust concentration of the spiral hopper inlet is reduced by 56.9% due to the impact velocity of particles is small, and the secondary fugitive dust is controlled inside a semi-closed space formed by the spiral guide plate. It is thus concluded that the spiral hopper provides an effective way in dust control. Full article
(This article belongs to the Section Computational Methods)
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Open AccessArticle
Mathematical Model Describing HIV Infection with Time-Delayed CD4 T-Cell Activation
Processes 2020, 8(7), 782; https://doi.org/10.3390/pr8070782 - 04 Jul 2020
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Abstract
A mathematical model composed of two non-linear differential equations that describe the population dynamics of CD4 T-cells in the human immune system, as well as viral HIV viral load, is proposed. The invariance region is determined, classical equilibrium stability analysis is performed by [...] Read more.
A mathematical model composed of two non-linear differential equations that describe the population dynamics of CD4 T-cells in the human immune system, as well as viral HIV viral load, is proposed. The invariance region is determined, classical equilibrium stability analysis is performed by using the basic reproduction number, and numerical simulations are carried out to illustrate stability results. Thereafter, the model is modified with a delay term, describing the time required for CD4 T-cell immunological activation. This generates a two-dimensional integro-differential system, which is transformed into a system with three ordinary differential equations. For the new model, equilibriums are determined, their local stability is examined, and results are studied by way of numerical simulation. Full article
(This article belongs to the Special Issue Numerical Simulation and Control for Disease)
Open AccessArticle
A Two-Patch Mathematical Model for Temperature-Dependent Dengue Transmission Dynamics
Processes 2020, 8(7), 781; https://doi.org/10.3390/pr8070781 - 03 Jul 2020
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Abstract
Dengue fever has been a threat to public health not only in tropical regions but non-tropical regions due to recent climate change. Motivated by a recent dengue outbreak in Japan, we develop a two-patch model for dengue transmission associated with temperature-dependent parameters. The [...] Read more.
Dengue fever has been a threat to public health not only in tropical regions but non-tropical regions due to recent climate change. Motivated by a recent dengue outbreak in Japan, we develop a two-patch model for dengue transmission associated with temperature-dependent parameters. The two patches represent a park area where mosquitoes prevail and a residential area where people live. Based on climate change scenarios, we investigate the dengue transmission dynamics between the patches. We employ an optimal control method to implement proper control measures in the two-patch model. We find that blockage between two patches for a short-term period is effective in a certain degree for the disease control, but to obtain a significant control effect of the disease, a long-term blockage should be implemented. Moreover, the control strategies such as vector control and transmission control are very effective, if they are implemented right before the summer outbreak. We also investigate the cost-effectiveness of control strategies such as vaccination, vector control and virus transmission control. We find that vector control and virus transmission control are more cost-effective than vaccination in case of Korea. Full article
(This article belongs to the Special Issue Numerical Simulation and Control for Disease)
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Open AccessFeature PaperArticle
Compartment Model of Mixing in a Bubble Trap and Its Impact on Chromatographic Separations
Processes 2020, 8(7), 780; https://doi.org/10.3390/pr8070780 - 03 Jul 2020
Viewed by 165
Abstract
Chromatography equipment includes hold-up volumes that are external to the packed bed and usually not considered in the development of chromatography models. These volumes can substantially contribute to band-broadening in the system and deteriorate the predicted performance. We selected a bubble trap of [...] Read more.
Chromatography equipment includes hold-up volumes that are external to the packed bed and usually not considered in the development of chromatography models. These volumes can substantially contribute to band-broadening in the system and deteriorate the predicted performance. We selected a bubble trap of a pilot scale chromatography system as an example for a hold-up volume with a non-standard mixing behavior. In a worst-case scenario, the bubble trap is not properly flushed before elution, thus causing the significant band-broadening of the elution peak. We showed that the mixing of buffers with different densities in the bubble trap device can be accurately modeled using a simple compartment model. The model was calibrated at a wide range of flow rates and salt concentrations. The simulations were performed using the open-source software CADET, and all scripts and data are published with this manuscript. The results illustrate the importance of including external holdup volumes in chromatography modeling. The band-broadening effect of tubing, pumps, valves, detectors, frits, or any other zones with non-standard mixing behavior can be considered in very similar ways. Full article
(This article belongs to the Special Issue Redesign Processes in the Age of the Fourth Industrial Revolution)
Open AccessArticle
Finite Element Analysis on Bingham–Papanastasiou Viscoplastic Flow in a Channel with Circular/Square Obstacles: A Comparative Benchmarking
Processes 2020, 8(7), 779; https://doi.org/10.3390/pr8070779 - 03 Jul 2020
Viewed by 170
Abstract
A CFD (computational fluid dynamics) analysis was carried out for the Bingham viscoplastic fluid flow simulations around cylinders of circular and square shapes. The governing equations in space were discretized with the finite element approach via a weak formulation and utilizing Ladyzhenskaya–Babuška–Brezzi-stable pair [...] Read more.
A CFD (computational fluid dynamics) analysis was carried out for the Bingham viscoplastic fluid flow simulations around cylinders of circular and square shapes. The governing equations in space were discretized with the finite element approach via a weak formulation and utilizing Ladyzhenskaya–Babuška–Brezzi-stable pair Q 2 / P 1 disc for approximation of the velocity and pressure profiles. The discrete non-linear system was linearized through Newton’s method, and a direct linear solver was iterated as an inner core solver. The study predicts the functional dependence and impact of Bingham number, B n , on the drag coefficient and lift coefficient. The effect of the shape of an obstacle is also provided by providing comparative data for the hydrodynamic forces with the published results. Full article
(This article belongs to the Special Issue Fluid Flow and Heat Transfer of Nanofluids)
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Open AccessArticle
Studies on the Potential of Nonmodified and Metal Oxide-Modified Coal Fly Ash Zeolites For Adsorption of Heavy Metals and Catalytic Degradation of Organics for Waste Water Recovery
Processes 2020, 8(7), 778; https://doi.org/10.3390/pr8070778 - 03 Jul 2020
Viewed by 183
Abstract
A nanocrystalline zeolite of Na-X type (CFAZ) was synthesized by ultrasonic-assisted double stage fusion-hydrothermal alkaline conversion of lignite coal fly ash. Modified CFAZ with magnetic nanoparticles (MNP-CFAZ) was obtained by adding presynthesized magnetic nanoparticles between the synthesis stages. CFAZs loaded by particles of [...] Read more.
A nanocrystalline zeolite of Na-X type (CFAZ) was synthesized by ultrasonic-assisted double stage fusion-hydrothermal alkaline conversion of lignite coal fly ash. Modified CFAZ with magnetic nanoparticles (MNP-CFAZ) was obtained by adding presynthesized magnetic nanoparticles between the synthesis stages. CFAZs loaded by particles of copper (Cu-CFAZ) and cobalt (Co-CFAZ) oxides were prepared by postsynthesis modification of the parent CFAZ, applying a wet impregnation technique. The parent and modified CFAZs were examined for their phase composition by X-ray diffraction, morphology by scanning electron microscopy, and surface characteristics by N2 physisorption. Comparative studies have been carried out on the adsorption capacity of the starting CFAZ and its derivatives with respect to Cd2+- and Pb2+-ions from aqueous solutions. Adsorption isotherms of Cd2+-ions on the studied samples were plotted and described by the adsorption equations of Langmuir, Freundlich, Langmuir–Freundlich, and Temkin. The best correlation between the experimental and model isotherms for the parent and modified CFAZ was found with the Langmuir linear model, assuming a monolayer adsorption mechanism. Parent and modified CFAZs were also studied as catalysts for heterogeneous thermal Fenton oxidation of methylene blue. At 90 °C, the higher catalytic activity exhibits the nonmodified sample, but with the decrease in temperature to 60 °C, the modified samples are more effective catalysts. Full article
(This article belongs to the Special Issue Sustainable Remediation Processes Based on Zeolites)
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Open AccessArticle
Alternative Briquette Material Made from Palm Stem Biomass Mediated by Glycerol Crude of Biodiesel Byproducts as a Natural Adhesive
Processes 2020, 8(7), 777; https://doi.org/10.3390/pr8070777 - 02 Jul 2020
Viewed by 262
Abstract
Recently, the global population has increased sharply, unfortunately, the availability of fossil fuel resources has significantly decreased. This phenomenon has become an attractive issue for many researchers in the world so that various studies in the context of finding renewable energy are developing [...] Read more.
Recently, the global population has increased sharply, unfortunately, the availability of fossil fuel resources has significantly decreased. This phenomenon has become an attractive issue for many researchers in the world so that various studies in the context of finding renewable energy are developing continuously. Relating to this challenge, this research has been part of scientific work in the context of preparing an energy briquette employing palm oil stems and glycerol crude of biodiesel byproducts as inexpensive and green materials easily found in the Riau province, Indonesia. Technically, the palm oil stems are used for the production of charcoal particles and the glycerol crude as an adhesive compound in the production of energy briquettes. The heating value of palm oil stem is 17,180 kJ/kg, which can be increased to an even higher value through a carbonization process followed by a densification process so that it can be used as a potential matrix to produce energy briquettes. In detail, this study was designed to find out several parameters including the effect of sieve sizes consisting of 60, 80, and 100 mesh, respectively, which are used for the preparation of charcoal particles as the main matrix for the manufacture of the briquettes; the effect of charcoal-adhesive ratios (wt) of 60:40, 70:30, and 80:20; and the effect of varied pressures of 100, 110, and 120 kg/cm2 on the briquette quality. The quality of the obtained briquettes is analyzed through the observation of important properties which involve the heating value and the compressive strength using Response Surface Methodology (RSM). The results showed that the produced briquettes had an optimum heating value of 30,670 kJ/kg, while their loaded charcoal particles resulted from the mesh sieve of 80, in which there was a charcoal loading of 53 g and it pressed at 93.1821 bar, whereas, the compressive strength value of the briquette was 100,608 kg/cm2, which loaded charcoal particles from the mesh sieve of 100, the charcoal-adhesive ratio of 53:47 (wt) and the pressure of 93.1821 bar. Full article
(This article belongs to the Special Issue Progress in Thermochemical Conversion of Solid Fuels)
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Open AccessArticle
Is Recycling Always the Best Option? Environmental Assessment of Recycling of Seashell as Aggregates in Noise Barriers
Processes 2020, 8(7), 776; https://doi.org/10.3390/pr8070776 - 02 Jul 2020
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Abstract
Waste recycling is an essential part of waste management. The concrete industry allows the use of large quantities of waste as a substitute for a conventional raw material without sacrificing the technical properties of the product. From a circular economy point of view, [...] Read more.
Waste recycling is an essential part of waste management. The concrete industry allows the use of large quantities of waste as a substitute for a conventional raw material without sacrificing the technical properties of the product. From a circular economy point of view, this is an excellent opportunity for waste recycling. Nevertheless, in some cases, the recycling process can be undesirable because it does not involve a net saving in resource consumption or other environmental impacts when compared to the conventional production process. In this study, the environmental performance of conventional absorption porous barriers, composed of 86 wt % of natural aggregates and 14 wt % cement, was compared with barriers composed of 80 wt % seashell waste and 20 wt % cement through an attributional cradle-to-grave life cycle assessment. The results show that, for the 11 environmental impact categories considered, the substitution of the natural aggregates with seashell waste involves higher environmental impacts, between 32% and 267%. These results are justified by the high contribution to these impacts of the seashell waste pre-treatment and the higher cement consumption. Therefore, the recycling of seashells in noise barrier manufacturing is not justified from an environmental standpoint with the current conditions. In this sense, it could be concluded that life cycle assessments should be carried out simultaneously with the technical development of the recycling process to ensure a sustainable solution. Full article
(This article belongs to the Special Issue Gas, Water and Solid Waste Treatment Technology)
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Open AccessFeature PaperArticle
Modeling the Effect of Channel Tapering on the Pressure Drop and Flow Distribution Characteristics of Interdigitated Flow Fields in Redox Flow Batteries
Processes 2020, 8(7), 775; https://doi.org/10.3390/pr8070775 - 01 Jul 2020
Viewed by 223
Abstract
Optimization of flow fields in redox flow batteries can increase performance and efficiency, while reducing cost. Therefore, there is a need to establish a fundamental understanding on the connection between flow fields, electrolyte flow management and electrode properties. In this work, the flow [...] Read more.
Optimization of flow fields in redox flow batteries can increase performance and efficiency, while reducing cost. Therefore, there is a need to establish a fundamental understanding on the connection between flow fields, electrolyte flow management and electrode properties. In this work, the flow distribution and pressure drop characteristics of interdigitated flow fields with constant and tapered cross-sections are examined numerically and experimentally. Two simplified 2D along-the-channel models are used: (1) a CFD model, which includes the channels and the porous electrode, with Darcy’s viscous resistance as a momentum sink term in the latter; and (2) a semi-analytical model, which uses Darcy’s law to describe the 2D flow in the electrode and lubrication theory to describe the 1D Poiseuille flow in the channels, with the 2D and 1D sub-models coupled at the channel/electrode interfaces. The predictions of the models are compared between them and with experimental data. The results show that the most influential parameter is γ , defined as the ratio between the pressure drop along the channel due to viscous stresses and the pressure drop across the electrode due to Darcy’s viscous resistance. The effect of R e in the channel depends on the order of magnitude of γ , being negligible in conventional cells with slender channels that use electrodes with permeabilities in the order of 10 12 m 2 and that are operated with moderate flow rates. Under these conditions, tapered channels can enhance mass transport and facilitate the removal of bubbles (from secondary reactions) because of the higher velocities achieved in the channel, while being pumping losses similar to those of constant cross-section flow fields. This agrees with experimental data measured in a single cell operated with aqueous vanadium-based electrolytes. Full article
(This article belongs to the Special Issue CFD Applications in Energy Engineering Research and Simulation)
Open AccessArticle
Plasma Catalytic Conversion of CH4 to Alkanes, Olefins and H2 in a Packed Bed DBD Reactor
Processes 2020, 8(7), 774; https://doi.org/10.3390/pr8070774 - 01 Jul 2020
Viewed by 234
Abstract
Methane is activated at ambient conditions in a dielectric barrier discharge (DBD) plasma reactor packed with Pd/γ-alumina catalyst containing different loadings of Pd (0.5, 1, 5 wt%). Results indicate that the presence of Pd on γ-alumina substantially abates the formation of deposits, leads [...] Read more.
Methane is activated at ambient conditions in a dielectric barrier discharge (DBD) plasma reactor packed with Pd/γ-alumina catalyst containing different loadings of Pd (0.5, 1, 5 wt%). Results indicate that the presence of Pd on γ-alumina substantially abates the formation of deposits, leads to a notable increase in the production of alkanes and olefins and additionally improves the energy efficiency compared to those obtained for the non-packed reactor and the bare γ-alumina packed reactor. A low amount of Pd (0.5 and 1 wt%) favors achieving a higher production of olefins (mainly C2H4 and C3H6) and a higher yield of H2. Increasing Pd loading to 5 wt% promotes the interaction of H2 and olefins, which consequently intensifies the successive hydrogenation of unsaturated compounds, thus incurring a higher production of alkanes (mainly C2H6 and C3H8). The substantial abatement of the deposits is ascribed to the role of Palladium in moderating the strength of the electric and shifting the reaction pathways, in the way that hydrogenation reactions of deposits’ precursors become faster than their deposition on the catalyst. Full article
(This article belongs to the Special Issue Advances in Methane and CO2 Activation and Conversion)
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Open AccessFeature PaperArticle
Experimental and Numerical Investigation of the Air Side Heat Transfer of a Finned Tubes Heat Exchanger
Processes 2020, 8(7), 773; https://doi.org/10.3390/pr8070773 - 01 Jul 2020
Viewed by 222
Abstract
The heat transfer was experimentally and numerically studied in this article. Characteristics of circular fins over a bent tube at different tube orientations and air velocities were investigated, and then compared with analytical results from the literature. For the experimental investigation, a simple [...] Read more.
The heat transfer was experimentally and numerically studied in this article. Characteristics of circular fins over a bent tube at different tube orientations and air velocities were investigated, and then compared with analytical results from the literature. For the experimental investigation, a simple setup was compiled inside of a wind tunnel, where the velocity and the inlet temperature of the air; the volume flow rate; and the inlet and outlet temperatures of the water were measured. Three different orientations were investigated with the set-up: the bent tube in line with the air flow with the same and opposite water inlet positions, and the bent tube perpendicular to the air flow. According to the results, the position has a significant effect on the heat transfer coefficient. A numerical study was also performed in accordance with the measurements in ANSYS-CFX computational fluid dynamics (CFD) software. The results of the CFD showed an acceptable correlation with the results of measurement; however, the results of analytical calculation from the literature show a significant discrepancy; the calculated heat performance is only about one-third of the measured values. This article presents the steps of measurement, simulation and analytical calculations, and shows solution possibilities in the calculation of the air-side heat transfer functions. Full article
(This article belongs to the Special Issue Modeling, Simulation and Computation on Dynamics of Complex Fluids)
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