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Showing records 1 to 25 of 268. [First] Page: 1 2 3 4 5 Last
Applications of Electrolyzed Water as a Sanitizer in the Food and Animal-By Products Industry
Juan C. Ramírez Orejel, José A. Cano-Buendía
July 2, 2020 (v1)
Keywords: electrolyzed water, foodborne pathogens, sanitization
Food demand is increasing every year and, usually animal-derived products are generated far from consumer-places. New technologies are being developed to preserve quality characteristics during processing and transportation. One of them is electrolyzed water (EW) that helps to avoid or decrease the development of foodborne pathogens, or losses by related bacteria. Initially, EW was used in ready-to-eat foods such as spinach, lettuce, strawberries, among others; however, its application in other products is under study. Every product has unique characteristics that require an optimized application of EW. Different sanitizers have been developed; unfortunately, they could have undesirable effects like deterioration of quality or alterations in sensory properties. Therefore, EW is gaining popularity in the food industry due to its characteristics: easy application and storage, no corrosion of work surfaces, absence of mucosal membrane irritation in workers handling food, and it is conside... [more]
Production of Ethanol from Hemicellulosic Sugars of Exhausted Olive Pomace by Escherichia coli
Juan Carlos López-Linares, Irene Gómez-Cruz, Encarnación Ruiz, Inmaculada Romero, Eulogio Castro
July 2, 2020 (v1)
Keywords: acid hydrolysate, biorefinery, detoxification, Fermentation, lignocellulosic residue
Exhausted olive pomace (EOP) is the main residue generated in olive oil industries, after the extraction of the residual oil from olive pomace with hexane. This work studies the ethanol production from hemicellulosic sugars of EOP. The fermentability of the sugar solution, resulting from the acid pretreatment of EOP, was evaluated using Escherichia coli SL100, although a detoxification step was required before fermentation. Overliming and activated charcoal detoxification were tested to minimize the presence of inhibitory compounds in the hydrolysate and to achieve a fermentable medium. E. coli assimilated all sugars in both detoxified hydrolysates and achieved ethanol yields of about 90% of the theoretical one. However, the fermentation time was much shorter when the hydrolysate had been detoxified with activated charcoal (20 h versus 120 h).
Catalytic Aquathermolysis of Boca de Jaruco Heavy Oil with Nickel-Based Oil-Soluble Catalyst
Alexey V. Vakhin, Firdavs A. Aliev, Irek I. Mukhamatdinov, Sergey A. Sitnov, Andrey V. Sharifullin, Sergey I. Kudryashov, Igor S. Afanasiev, Oleg V. Petrashov, Danis K. Nurgaliev
July 2, 2020 (v1)
Keywords: aquathermolysis, catalyst, heavy oil, in situ upgrading, nickel, SARA-analysis
This paper investigates aquathermolysis of heavy oil in carbonate reservoir rocks from Boca de Jaruco, which is developed by the cyclic steam stimulation method. The nickel-based catalyst precursor was introduced in order to intensify the conversion processes of heavy oil components. The active form of such catalysts—nickel sulfides—are achieved after steam treatment of crude oil at reservoir conditions. The experiments were carried out on a rock sample extracted from the depth of 1900 m. Changes in composition and structure of heavy oil after the conversion were identified using SARA-analysis, Gas Chromatography-Mass Spectroscopy of saturated fractions, FTIR spectroscopy of saturated fractions, and MALDI of resins. It is revealed that catalyst particles provide a reduction in the content of resins and asphaltenes due to the destruction of carbon-heteroatom bonds. Moreover, the destruction of C=Carom. bonds and interactions with aromatic rings are heightened. In contrast, the results o... [more]
Polyphenol Content and Biological Activities of Ruta graveolens L. and Artemisia abrotanum L. in Northern Saudi Arabia
Hosam O. Elansary, Agnieszka Szopa, Paweł Kubica, Halina Ekiert, Diaa O. El-Ansary, Fahed A. Al-Mana, Eman A. Mahmoud
July 2, 2020 (v1)
Keywords: antibacterial, antifungal, antioxidant, antiproliferative, Artemisia abrotanum, cytotoxicity, flavonoids, leaf extract, phenolic acids, Ruta graveolens
Natural populations of Ruta graveolens L. and Artemisia abrotanum L. in northern Saudi Arabia may be a rich source of natural polyphenols with potential biological activities. Therefore, tentative high-performance liquid chromatography−diode array detection was used to analyze the polyphenol contents of leaf extracts. R. graveolens mainly contained the phenolic acids chlorogenic acid and p-coumaric acid and the flavonoids rutoside and quercetin, whereas those of A. abrotanum mainly contained the phenolic acids isochlorogenic acid and rosmarinic acid and the flavonoid quercetin. Leaf extracts of both species showed antioxidant activities due to the presence of quercetin, chlorogenic acid, and p-coumaric acid as well as antiproliferative and cytotoxic activities against cancer cells, which may be attributed to necrotic cell accumulation during the early and late apoptotic periods. Both species also exhibited antibacterial activity, although the activity was higher in R. graveolens due to... [more]
Controlling the Skin Barrier Quality through the Application of Polymeric Films Containing Microspheres with Encapsulated Plant Extract
Justyna Kozlowska, Bartosz Tylkowski, Natalia Stachowiak, Weronika Prus-Walendziak
July 2, 2020 (v1)
Subject: Biosystems
Keywords: Calendula officinalis flower extract, encapsulation, microspheres, polymer films, skin barrier, sodium alginate, starch, transepidermal water loss
Human skin has protective functions and it is a barrier that protects the interior of the body from harmful environmental factors and pathogen penetration. An important role of the skin is also to prevent the loss of water from the body and if the skin barrier is damaged, the amount of water emitted from the internal environment is increased. Therefore, it is crucial to recovery and maintenance of epidermal barrier integrity. The aim of the current work was to encapsulate Calendula officinalis flower extract in gelatin microspheres and then incorporation microspheres into thin polymeric films made from sodium alginate or mixture of sodium alginate and starch. Such materials may find applications in the cosmetic field for example in the preparation of masks for skin, according to the Calendula officinalis flower extract wide influence on skin condition. Thus, the release profile of this extract from the materials was tested under conditions corresponding to the skin (pH 5.4, 37 °C). The... [more]
Numerical Modeling of Transport Phenomena in the Horizontal Single Belt Casting (HSBC) Process for the Production of AA6111 Aluminum Alloy Strip
Usman Niaz, Mihaiela Minea Isac, Roderick I. L. Guthrie
July 2, 2020 (v1)
Keywords: computational fluid dynamics (CFD), double impingement feeding system, horizontal single belt casting process (HSBC)
In this research study, numerical modelling and experimental casting of AA6111 strips, 250 mm wide, 6 mm thick, was conducted. The velocity of the molten AA6111 alloy at the nozzle slot outlet was raised to 2 m/s, whilst the belt speed was kept at 0.3 m/s. The numerical model demonstrates considerable turbulence/fluctuations in the flow of the molten AA6111 alloy in the HSBC process, rendering its free surface highly non-uniform and uneven. These discontinuites in the flow resulted from the sudden impact of molten metal onto the inclined refractory plane, and then onto the slowly moving belt. However, it has been determined that these surface variations are rapidly damped, and as such are not detrimental to final strip surface quality. Any surface perturbations remaining can be eliminated via hot plastic deformation. The experimental findings are in accordance with the model predictions. Furthermore, at high metal heads inside the delivery launder, the molten metal was observed to be f... [more]
A General Stroke-Based Model for the Straightening Process of D-Type Shaft
Hong Lu, Yue Zang, Xinbao Zhang, Yongquan Zhang, Le Li
July 2, 2020 (v1)
Keywords: D-type shaft, prediction of straightening parameters, straightening process, stroke-based straightening model, three-dimensional bending deformation
D-type shaft is widely used in precision machinery products such as motors and intelligent robots. The straightness of the D-type shaft is an important factor influencing its machining accuracy and dynamic performance, which is normally improved by the three-point pressure straightening process. This paper proposes a general stroke-based model to predict the relevant parameters for the straightening process of D-type shaft, considering the bending deformations in three dimensions. The distribution of stress and strain inside the D-type shaft during the straightening process in arbitrary position of the cross section and the bending moment are analyzed by using linear hardening material model. The relationship between deflection and the internal stress on the loading position is explored, and a straightening stroke model of D-type shaft is obtained. The correctness of the stroke-based straightening model has been validated by finite element method (FEM) simulation analysis and bending e... [more]
Valorization of OFMSW Digestate-Derived Syngas toward Methanol, Hydrogen, or Electricity: Process Simulation and Carbon Footprint Calculation
Aristide Giuliano, Enrico Catizzone, Cesare Freda, Giacinto Cornacchia
July 2, 2020 (v1)
Keywords: bio-hydrogen, bio-methanol, digestate, gasification, low carbon processes, process simulation
This paper explores a possible waste-based economy transition strategy. Digestate from the organic fraction of municipal solid waste (OFMSW) is considered, as well as a low-added value product to be properly valorized. In this regard, air gasification may be used to produce syngas. In this work, the production of methanol, hydrogen, or electricity from digestate-derived syngas was assessed by ChemCAD process simulation software. The process scheme of methanol production comprises the following parts: water gas shift (WGS) with carbon capture and storage units (CCS), methanol synthesis, and methanol purification. In the case of hydrogen production, after WGS-CCS, hydrogen was purified from residual nitrogen by pressure swing absorption (PSA). Finally, for electricity production, the digestate-derived syngas was used as fuel in an internal combustion engine. The main objective of this work is to compare the proposed scenarios in terms of CO2 emission intensity and the effect of CO2 stora... [more]
Plant-Based Tacca leontopetaloides Biopolymer Flocculant (TBPF) Produced High Removal of Turbidity, TSS, and Color for Leachate Treatment
Nurul Shuhada Mohd Makhtar, Juferi Idris, Mohibah Musa, Yoshito Andou, Ku Halim Ku Hamid, Siti Wahidah Puasa
July 2, 2020 (v1)
Keywords: flocculant properties, leachate, Tacca leontopetaloides biopolymer flocculant (TBPF), Tacca leontopetaloides sp.
Wastewater treatment is crucial to ensure a sustainable supply of clean water, especially for human use. Natural flocculants can overcome the disadvantages of chemical flocculants in wastewater treatment. This study proposes a new natural-based flocculant from the Tacca leontopetaloides plant for leachate treatment. The plant tuber was processed through gelatinization to produce Tacca leontopetaloides biopolymer flocculant (TBPF). The characterization of TBPF for flocculant properties was investigated, and the performance of TBPF on leachate treatment using a standard jar test procedure was examined at different pH values of leachate and TBPF dosages. The characteristics of TBPF in terms of amylose/amylopectin fraction, viscosity, and zeta potential were 26:74, 0.037−0.04 Pa·s, and −13.14 mV, respectively. The presence of −COOH and −OH structure in TBPF indicates the flocculant properties. TBPF reduced the turbidity, total suspended solids (TSS), and color from 218 NTU, 214 mg/L, 14201... [more]
Dentistry 4.0 Concept in the Design and Manufacturing of Prosthetic Dental Restorations
Leszek A. Dobrzański, Lech B. Dobrzański
July 2, 2020 (v1)
Subject: Other
Keywords: additive manufacturing technologies, CAD/CAM methods, CBCT tomography, dental implants, dental prosthesis restoration manufacturing center, Dentistry 4.0, hybrid multilayer biological-engineering composites biomaterials, implant-scaffolds, Industry 4.0, prosthetic restorations, selective laser sintering, stereolithography, stomatognathic system, surgical guide
The paper is a comprehensive but compact review of the literature on the state of illnesses of the human stomatognathic system, related consequences in the form of dental deficiencies, and the resulting need for prosthetic treatment. Types of prosthetic restorations, including implants, as well as new classes of implantable devices called implant-scaffolds with a porous part integrated with a solid core, as well as biological engineering materials with the use of living cells, have been characterized. A review of works on current trends in the technical development of dental prosthetics aiding, called Dentistry 4.0, analogous to the concept of the highest stage of Industry 4.0 of the industrial revolution, has been presented. Authors’ own augmented holistic model of Industry 4.0 has been developed and presented. The studies on the significance of cone-beam computed tomography (CBCT) in planning prosthetic treatment, as well as in the design and manufacture of prosthetic restorations, h... [more]
Pollen Bee Aqueous Extract-Based Synthesis of Silver Nanoparticles and Evaluation of Their Anti-Cancer and Anti-Bacterial Activities
Hanan M. Al-Yousef, Musarat Amina, Ali S. Alqahtani, Mohammed S. Alqahtani, Abdul Malik, Mohammad Rafe Hatshan, Mohammed Rafiq H. Siddiqui, Mujeeb Khan, Mohammed Rafi Shaik, Mohammad Shamsul Ola, Rabbani Syed
July 2, 2020 (v1)
Subject: Biosystems
Keywords: anti-bacterial, anti-cancer, bee pollen aqueous extract, eco-friendly, silver nanoparticles
Bee pollens are rich source of essential amino acids and are often considered as complete food for human beings. Herein, we exploited the potential reducing abilities of Bee pollens extract for the eco-friendly preparation of silver nanoparticles (AgNPs-G). The resulting NPs were characterized using a combination of microscopic and spectroscopic techniques. The analyses confirm the formation of spherical Ag NPs. AgNPs-G obtained from the aqueous extract of bee pollens was used to study their antibacterial properties against Gram-positive and Gram-negative microbes using the Minimum Inhibitory Concentration 50 (MIC50) method. The antibacterial properties of AgNPs-G were compared to the properties of chemically synthesized Ag NPs (AgNPs-C) using sodium borohydride as a reducing agent. The green synthesized nanoparticles (AgNPs-G) exhibited a better antibacterial activity against most of the studied strains when compared to the chemically synthesized Ag NPs (AgNPs-C). In addition, the ant... [more]
A Review on Insights for Green Production of Unconventional Protein and Energy Sources Derived from the Larval Biomass of Black Soldier Fly
Sabrina Hasnol, Kunlanan Kiatkittipong, Worapon Kiatkittipong, Chung Yiin Wong, Cheng Seong Khe, Man Kee Lam, Pau Loke Show, Wen Da Oh, Thiam Leng Chew, Jun Wei Lim
July 2, 2020 (v1)
Keywords: biodiesel, black soldier fly larvae, lipid, protein, substrate, transesterification
The purpose of this review is to reveal the lipid and protein contents in black soldier fly larvae (BSFL) for the sustainable production of protein and energy sources. It has been observed from studies in the literature that the larval lipid and protein contents vary with the rearing conditions as well as the downstream processing employed. The homogenous, heterogenous and microbial-treated substrates via fermentation are used to rear BSFL and are compared in this review for the simultaneous production of larval protein and biodiesel. Moreover, the best moisture content and the aeration rate of larval feeding substrates are also reported in this review to enhance the growth of BSFL. As the downstream process after harvesting starts with larval inactivation, various related methods have also been reviewed in relation to its impact on the quality/quantity of larval protein and lipids. Subsequently, the other downstream processes, namely, extraction and transesterification to biodiesel, a... [more]
Catalytic Performance of Metal Oxides Promoted Nickel Catalysts Supported on Mesoporous γ-Alumina in Dry Reforming of Methane
Anis H. Fakeeha, Abdulaziz A. Bagabas, Mahmud S. Lanre, Ahmed I. Osman, Samsudeen O. Kasim, Ahmed A. Ibrahim, Rasheed Arasheed, Abdulmajeed Alkhalifa, Ahmed Y. Elnour, Ahmed E. Abasaeed, Ahmed S. Al-Fatesh
July 2, 2020 (v1)
Keywords: Dry Reforming, Gd-promoted catalyst, mesoporous γ-alumina, metal oxide promoters, methane, Ni-based catalyst, synthesis gas
Dry reforming of CH4 was conducted over promoted Ni catalysts, supported on mesoporous gamma-alumina. The Ni catalysts were promoted by various metal oxides (CuO, ZnO, Ga2O3, or Gd2O3) and were synthesized by the incipient wetness impregnation method. The influence of the promoters on the catalyst stability, coke deposition, and H2/CO mole ratio was investigated. Stability tests were carried out for 460 min. The H2 yield was 87% over 5Ni+1Gd/Al, while the CH4 and CO2 conversions were found to decrease in the following order: 5Ni+1Gd/Al > 5Ni+1Ga/Al > 5Ni+1Zn/Al > 5Ni/Al > 5Ni+1Cu/Al. The high catalytic performance of 5Ni+1Gd/Al, 5Ni+1Ga/Al, and 5Ni+1Zn/Al was found to be closely related to their contents of NiO species, which interacted moderately and strongly with the support, whereas free NiO in 5Ni+1Cu/Al made it catalytically inactive, even than 5Ni/Al. The 5Ni+1Gd/Al catalyst showed the highest CH4 conversion of 83% with H2/CO mole ratio of ~1.0.
Fabrication of Highly Filled Composites with an Innovative Miniaturized Spouted Bed
Hannah Sophia Rothberg, Swantje Pietsch, Gerold A. Schneider, Stefan Heinrich
July 2, 2020 (v1)
Keywords: highly filled composites, mechanical properties of composites, miniaturized spouted bed, particle coating, three-point bending test
In nature bio-composites such as nacre show remarkable mechanical properties due to their complex hierarchical structure and high-volume fraction of its hard component. These composites are highly interesting for structural applications in different branches of industries for mechanical engineering and process technology. The aim of this work was to provide a scalable method for the production of highly filled composites by mimicking the structure of bio-composites. Therefore, composites from iron oxide (Fe2O3) and SBC-polymer (styrene-butadiene block copolymer) were fabricated by using a miniaturized spouted bed with an innovative fluidization gap design. Small iron oxide particles (25−45 μm) were fluidized in the spouted bed and coated with a polymer solution via a bottom spray nozzle. Afterwards the coated granules were hot-pressed and the mechanical properties of the obtained composites were tested. By this method composites with a bending strength of up to 6 MPa were fabricated. A... [more]
Novel Carbon Dioxide-Based Method for Accurate Determination of pH and pCO2 in Mammalian Cell Culture Processes
Christian Klinger, Verena Trinkaus, Tobias Wallocha
July 2, 2020 (v1)
Keywords: Carbon Dioxide, cell culture, cell culture, CHO, off-gas measurement, pCO2, pH, reference
In mammalian cell culture, especially in pharmaceutical manufacturing, pH is a critical process parameter that has to be controlled as accurately as possible. Not only does pH directly affect cell culture performance, ensuring a comparable pH is also crucial for scaling and transfer of processes. A sample-based offline pH measurement is commonly used to ensure correct bioreactor pH probe signals after sterilization and as a detection measure for drifts of probe signals. However, the sample-based pH offline measurement does not necessarily deliver required accuracy. Offsets between bioreactor pH and sample pH heavily depend on equipment, local procedures and the offline measurement method that is used. This article adequately describes a novel, non-invasive method to determine pH and pCO2 in sterile bioreactors without the need to sample and measure offline. This method utilizes the chemical correlation between carbon dioxide in the gas phase, dissolved carbon dioxide, bicarbonate and d... [more]
Integrating Support Vector Regression with Genetic Algorithm for Hydrate Formation Condition Prediction
Jie Cao, Shijie Zhu, Chao Li, Bing Han
July 2, 2020 (v1)
Keywords: gas hydrate, Genetic Algorithm, outlier detection, support vector machine
To predict the natural gas hydrate formation conditions quickly and accurately, a novel hybrid genetic algorithm−support vector machine (GA-SVM) model was developed. The input variables of the model are the relative molecular weight of the natural gas (M) and the hydrate formation pressure (P). The output variable is the hydrate formation temperature (T). Among 10 gas samples, 457 of 688 data points were used for training to identify the optimal support vector machine (SVM) model structure. The remaining 231 data points were used to evaluate the generalisation capability of the best trained SVM model. Comparisons with nine other models and analysis of the outlier detection revealed that the GA-SVM model had the smallest average absolute relative deviation (0.04%). Additionally, the proposed GA-SVM model had the smallest amount of outlier data and the best stability in predicting the gas hydrate formation conditions in the gas relative molecular weight range of 15.64−28.97 g/mol and the... [more]
A Deep Learning Method for Yogurt Preferences Prediction Using Sensory Attributes
Kexin Bi, Tong Qiu, Yizhen Huang
July 2, 2020 (v1)
Keywords: autoencoder, consumer preference, sensory attributes, support vector machine, yogurt
During the development of innovative products, consumer preferences are the essential factors for yogurt producers to improve their market share. A high-performance prediction method will be beneficial to understand the intrinsic relevance between preferences and sensory attributes. In this study, a novel deep learning method is proposed that uses an autoencoder to extract product features from the sensory attributes scored by experts, and the sensory features acquired are regressed on consumer preferences with support vector machine analysis. Model performance analysis, hedonic contour mapping, and feature clustering were implemented to validate the overall learning process. The results showed that the deep learning model can vouch an acceptable level of accuracy, and the hedonic mapping reflected could supply a great help for producers’ product design or modification. Finally, hierarchical clustering analysis revealed that for all three brands of yogurts, low temperature (4 °C) stora... [more]
A Study on the Water/Polymer Co-Flooding Seepage Law and Reasonable Polymer Injection Volume in Offshore Oilfields
Jiwei Wang, Liyang Song, Kaoping Song, Chi Dong, Lingyu Tian, Gang Chen
July 2, 2020 (v1)
Subject: Other
Keywords: offshore oilfield, polymer injection volume, seepage law, water/polymer co-flooding
To analyze the water/polymer co-flooding seepage law in offshore oilfields, we took the Jinzhou 9-3 oilfield as an example, analyzed the dynamic characteristics of water/polymer co-flooding, and then applied streamline simulation and tracer simulation technology to obtain the water/polymer co-flooding seepage law. The interference degree of the water/polymer co-flooding was quantified, and the accuracy of the seepage law was tested. Finally, a reasonable polymer injection volume was obtained using the economic law. The results demonstrated that the water-cut of the Jinzhou 9-3 oilfield in the water/polymer co-flooding stage was high, the annual decrease of polymer store ratio increased by 2.02 times, and the swept area of polymer was limited to some extent. Mutual interference existed in the water/polymer flooding, and the oil increment of per ton polymer decreased by 36.5%. In the late stage of the water/polymer co-flooding, the utilization rate of water and polymer was low, and the p... [more]
The Cultivation of Lipid-Rich Microalgae Biomass as Anaerobic Digestate Valorization Technology—A Pilot-Scale Study
Marcin Dębowski, Marcin Zieliński, Marta Kisielewska, Joanna Kazimierowicz, Magda Dudek, Izabela Świca, Aleksandra Rudnicka
July 2, 2020 (v1)
Subject: Biosystems
Keywords: anaerobic digestate, bio-oil, microalgae, photobioreactor
The aim of the study was to determine the use of digestate from anaerobic digestion of dairy wastewater as a culture medium for microalgae to obtain bio-oil. The experiments were conducted at a small scale in a closed raceway pond. The efficiency of the microalgae biomass production, the digestate treatment efficiency as well as the content and properties of the bio-oil obtained from the microalgal cells were analyzed. The produced biomass concentration was about 3000 ± 10.5 mg dry biomass/L, with an average growth rate of 160 ± 6.6 mgdm/L·d. The efficiency of organic compound and nutrient removal was above 90%. The bio-oil content in the biomass was about 20%. Based on the results of the study, a concept for technical-scale technology was developed.
Thermal Biomass Conversion: A Review
Witold M. Lewandowski, Michał Ryms, Wojciech Kosakowski
July 2, 2020 (v1)
Keywords: Biomass, gasification, pyrolysis, thermal conversion, torrefaction
In this paper, the most important methods of thermal conversion of biomass, such as: hydrothermal carbonization (180−250 °C), torrefaction (200−300 °C), slow pyrolysis (carbonization) (300−450 °C), fast pyrolysis (500−800 °C), gasification (800−1000 °C), supercritical steam gasification, high temperature steam gasification (>1000 °C) and combustion, were gathered, compared and ranked according to increasing temperature. A comprehensive model of thermal conversion as a function of temperature, pressure and heating rate of biomass has been provided. For the most important, basic process, which is pyrolysis, five mechanisms of thermal decomposition kinetics of its components (lignin, cellulose, hemicellulose) were presented. The most important apparatuses and implementing devices have been provided for all biomass conversion methods excluding combustion. The process of combustion, which is energy recycling, was omitted in this review of biomass thermal conversion methods for two reasons.... [more]
Modeling the Municipal Waste Collection Using Genetic Algorithms
Elisabete Alberdi, Leire Urrutia, Aitor Goti, Aitor Oyarbide-Zubillaga
July 2, 2020 (v1)
Keywords: genetic algorithms, traveling salesman problem, waste collection route planning
Calculating adequate vehicle routes for collecting municipal waste is still an unsolved issue, even though many solutions for this process can be found in the literature. A gap still exists between academics and practitioners in the field. One of the apparent reasons why this rift exists is that academic tools often are not easy to handle and maintain by actual users. In this work, the problem of municipal waste collection is modeled using a simple but efficient and especially easy to maintain solution. Real data have been used, and it has been solved using a Genetic Algorithm (GA). Computations have been done in two different ways: using a complete random initial population, and including a seed in this initial population. In order to guarantee that the solution is efficient, the performance of the genetic algorithm has been compared with another well-performing algorithm, the Variable Neighborhood Search (VNS). Three problems of different sizes have been solved and, in all cases, a s... [more]
Effects of Particle Size on Diffusion Kinetics in Chinese Anthracites during CH4 Desorption
Jie Zang, Kai Wang, Yanbin Yu
July 2, 2020 (v1)
Subject: Materials
Keywords: Chinese anthracite, desorption, diffusion kinetics, particle size
Diffusion kinetics is widely acknowledged to dominate gas flow in coal matrix blocks. Knowledge of this topic is important for ongoing coalbed methane recovery and CO2-enhanced coalbed methane production. Because laboratory diffusivity measurements are normally conducted on powdered coals, it is unclear how representative the results are for coalbeds. Investigations into the effects of particle size on gas diffusivity can provide insights into the in situ diffusivity of the coal matrix. This paper presents measured CH4 desorption data in two Chinese anthracites (one brittle, one hard) having different particle sizes, to investigate the effects of particle size on diffusion kinetics. The experimental data were fitted by both the unipore (UP) and bidisperse (BD) models. The BD model agreed better with the measured data than the UP model, especially for the brittle coal. This indicated that the brittle coal was more abundant in macropores than the hard coal. Diffusivity in the hard coal d... [more]
Metabolic Efficiency of Sugar Co-Metabolism and Phenol Degradation in Alicyclobacillus acidocaldarius for Improved Lignocellulose Processing
Ashley E. Beck
July 2, 2020 (v1)
Subject: Biosystems
Keywords: co-metabolism, dynamic flux balance analysis, elementary flux mode analysis, resource allocation, thermoacidophile
Substrate availability plays a key role in dictating metabolic strategies. Most microorganisms consume carbon/energy sources in a sequential, preferential order. The presented study investigates metabolic strategies of Alicyclobacillus acidocaldarius, a thermoacidophilic bacterium that has been shown to co-utilize glucose and xylose, as well as degrade phenolic compounds. An existing metabolic model was expanded to include phenol degradation and was analyzed with both metabolic pathway and constraint-based analysis methods. Elementary flux mode analysis was used in conjunction with resource allocation theory to investigate ecologically optimal metabolic pathways for different carbon substrate combinations. Additionally, a dynamic version of flux balance analysis was used to generate time-resolved simulations of growth on phenol and xylose. Results showed that availability of xylose along with glucose did not predict enhanced growth efficiency beyond that of glucose alone, but did predi... [more]
The Impact of Uncertainty Factors on the Decision-Making Process of Logistics Management
Łukasz Marzantowicz
July 2, 2020 (v1)
Keywords: conditions of uncertainty, logistic decisions, logistics management
The article is a contribution to the discussion on the possibilities of effective logistic decisions under the conditions of uncertainty. Variable and unpredictable factors, which create the conditions of uncertainty, not only directly affect logistic processes (positive or negative impact), but can also be a determinant of making decisions. Logistics management, because it is referred to in the context of decision-making, is currently defined by the quality of management decisions taken, including factors which often constitute only partially quantifiable sets. The main goal of the article is to show the strength of the dependence between the occurrence of uncertainty factors and the type of decision. On the basis of decision-making theory, the types of decisions were defined, and then a set of factors that are most important for a given type of decision was selected. The results of the analysis allowed the strength of the influence of uncertainty factors on making logistics decisions... [more]
Energetic Valorisation of Olive Biomass: Olive-Tree Pruning, Olive Stones and Pomaces
Juan Francisco García Martín, Manuel Cuevas, Chao-Hui Feng, Paloma Álvarez Mateos, Miguel Torres García, Sebastián Sánchez
July 2, 2020 (v1)
Keywords: bioethanol, combustion, gasification, olive, olive oils, olive pomaces, olive stones, olive-pruning debris, pyrolysis
Olive oil industry is one of the most important industries in the world. Currently, the land devoted to olive-tree cultivation around the world is ca. 11 × 106 ha, which produces more than 20 × 106 t olives per year. Most of these olives are destined to the production of olive oils. The main by-products of the olive oil industry are olive-pruning debris, olive stones and different pomaces. In cultures with traditional and intensive typologies, one single ha of olive grove annually generates more than 5 t of these by-products. The disposal of these by-products in the field can led to environmental problems. Notwithstanding, these by-products (biomasses) have a huge potential as source of energy. The objective of this paper is to comprehensively review the latest advances focused on energy production from olive-pruning debris, olive stones and pomaces, including processes such as combustion, gasification and pyrolysis, and the production of biofuels such as bioethanol and biodiesel. Futu... [more]
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