bluuebunny/crossref_metadata_2025 huggingface dataset:
Mathematical Modeling and Optimization of Fused Filament Fabrication (FFF) Process Parameters for Shape Deviation Control of Polyamide 6 Using Taguchi Method
Authors: Shakeri Zohreh , Benfriha Khaled , Shirinbayan Mohammadali , Ahmadifar Mohammad , Tcharkhtchi Abbas
Published: October 2021

Fused filament fabrication (FFF) is a layer-by-layer additive manufacturing (AM) process for producing parts. For industries to gain a competitive advantage, reducing product development cycle time is a basic goal. As a result, industries’ attention has turned away from traditional product development processes toward rapid prototyping techniques. Because different process parameters employed in this method significantly impact the quality of FFF manufactured parts, it is essential to optimize FFF process parameters to enhance component quality. The paper presents optimization of fused filament fabrication process parameters to improve the shape deviation such as cylindricity and circularity of 3D printed parts with the Taguchi optimization method. The effect of thickness, infill pattern, number of walls, and layer height was investigated as variable parameters for experiments on cylindricity and circularity. The MarkForged® used Nylon White (PA6) to create the parts. ANOVA and the S/N ratio are also used to evaluate and optimize the influence of chosen factors. As a result, it was concluded that the hexagonal infill pattern, the thickness of 5 mm, wall layer of 2, and a layer height of 1.125 mm were known to be the optimal process parameters for circularity and cylindricity in experiments. Then a linear regression model was created to observe the relationship between the control variables with cylindricity and circularity. The results were confirmed by a confirmation test.
Molds with Advanced Materials for Carbon Fiber Manufacturing with 3D Printing Technology
Authors: Ferretti Patrich , Santi Gian Maria , Leon-Cardenas Christian , Freddi Marco , Donnici Giampiero , Frizziero Leonardo , Liverani Alfredo
Published: October 2021

Fused Deposition Modeling (FDM) 3D printing is the most widespread technology in additive manufacturing worldwide that thanks to its low costs, finished component applications, and the production process of other parts. The need for lighter and higher-performance components has led to an increased usage of polymeric matrix composites in many fields ranging from automotive to aerospace. The molds used to manufacture these components are made with different technologies, depending on the number of pieces to be made. Usually, they are fiberglass molds with a thin layer of gelcoat to lower the surface roughness and obtain a smooth final surface of the component. Alternatively, they are made from metal, thus making a single carbon fiber prototype very expensive due to the mold build. Making the mold using FDM technology can be a smart solution to reduce costs, but due to the layer deposition process, the roughness is quite high. The surface can be improved by reducing the layer height, but it is still not possible to reach the same degree of surface finish of metallic or gelcoat molds without the use of fillers. Thermoplastic polymers, also used in the FDM process, are generally soluble in specific solvents. This aspect can be exploited to perform chemical smoothing of the external surface of a component. The combination of FDM and chemical smoothing can be a solution to produce low-cost molds with a very good surface finish.
Novel Ionic Conducting Composite Membrane Based on Polymerizable Ionic Liquids
Authors: Kobzar Yaroslav L. , Azzouz Ghania , Albadri Hashim , Levillain Jocelyne , Dez Isabelle , Gaumont Annie-Claude , Lecamp Laurence , Chappey Corinne , Marais Stéphane , Fatyeyeva Kateryna
Published: October 2021

In this work, the design and characterization of new supported ionic liquid membranes, as medium-temperature polymer electrolyte membranes for fuel-cell application, are described. These membranes were elaborated by the impregnation of porous polyimide Matrimid® with different synthesized protic ionic liquids containing polymerizable vinyl, allyl, or methacrylate groups. The ionic liquid polymerization was optimized in terms of the nature of the used (photo)initiator, its quantity, and reaction duration. The mechanical and thermal properties, as well as the proton conductivities of the supported ionic liquid membranes were analyzed in dynamic and static modes, as a function of the chemical structure of the protic ionic liquid. The obtained membranes were found to be flexible with Young’s modulus and elongation at break values were equal to 1371 MPa and 271%, respectively. Besides, these membranes exhibited high thermal stability with initial decomposition temperatures > 300 °C. In addition, the resulting supported membranes possessed good proton conductivity over a wide temperature range (from 30 to 150 °C). For example, the three-component Matrimid®/vinylimidazolium/polyvinylimidazolium trifluoromethane sulfonate membrane showed the highest proton conductivity—~5 × 10−2 mS/cm and ~0.1 mS/cm at 100 °C and 150 °C, respectively. This result makes the obtained membranes attractive for medium-temperature fuel-cell application.
Utilization of Radium-Bead Material for Road Safety: An Application of the Circular Economy Concept
Authors: Hussain Sajid , Zhou Xuemei , Shah Syyed Adnan Raheel , Ahmad Naveed , Anwar Muhammad Kashif , Basheer Muhammad Aamir
Published: October 2021

Road safety has become a serious issue in both developed and developing countries, costing billions of dollars every year. Road accidents at nighttime especially in low illumination situations are common and severe and have gained a lot of attention. To improve visibility and avoid traffic accidents, a series of efforts have been made but the existing mechanism is facing continuous challenges and highlighting a need for smart highways with high efficiency, road safety, and strength. In this study, the use of radium polymer beads (RPB) is proposed to avoid road accidents. The effect of RPB was investigated by comparing the results of the beads’ surface and modified asphalt mixtures using the three-stage testing methodology. Utilizing the circular economy, RPB have been introduced as a solution to the problem. Results indicated that in the first phase, the addition of RPB on the mixture surface improved the mechanical performance of the road pavement and helped in avoiding road accidents due to their ability to absorb the light from the source and then reflect in the night. Moreover, the mechanical properties using Marshall stability standard parameters (stability 9 kN and flow 2–4 mm range) were fulfilled as a standard testing requirement. The proposed radium bead layer can reduce road accidents and provide a direction towards future smart highways by using new reflective materials in road construction.
Determination of the Tensile Properties and Biodegradability of Cornstarch-Based Biopolymers Plasticized with Sorbitol and Glycerol
Authors: Harussani M. M. , Sapuan S. M. , Firdaus A. H. M. , El-Badry Yaser A. , Hussein Enas E. , El-Bahy Zeinhom M.
Published: October 2021

In this study, the effects of various quantities of sorbitol and glycerol plasticizers (0%, 30%, 45%, and 60%) on cornstarch-based film were examined to develop a novel polymer for usage with biodegradable materials. The film was prepared using the casting process. According to the test findings, the application of the plasticizer concentrations affected the thickness, moisture content, and water absorption of the film. When plasticizer concentrations were increased to 60%, the tensile stress and Young’s modulus of plasticized films dropped regardless of plasticizer type. However, the thin film with addition of 30% sorbitol plasticizer demonstrated a steady value of Young’s modulus (60.17 MPa) with an increase in tensile strength (13.61 MPa) of 46%, while the lowest combination of tensile strength and Young’s modulus is the film that was plasticized with 60% glycerol, with 2.33 MPa and 16.23 MPa, respectively. In summary, the properties and performance of cornstarch-based film were greatly influenced by plasticizer types and concentrations. The finest set of features in this research appeared in the film plasticized with 30% sorbitol, which achieved the best mechanical properties for food packaging applications.
Copolyamide–Clay Nanotube Polymer Composite Nanofiber Membranes: Preparation, Characterization and Its Asymmetric Wettability Driven Oil/Water Emulsion Separation towards Sewage Remediation
Authors: Bhagyaraj Sneha , Sobolčiak Patrik , Al-Ghouti Mohammad A. , Krupa Igor
Published: October 2021

To address the problem of ever-increasing oily wastewater management, due to its directional liquid transport property, membranes with asymmetric wettability can be effectively used for emulsion separation. This study reports the synthesis of electrospun polymer–clay nanocomposite nanofibers, using co-polyamide polymer (COPA) and halloysite nanotubes (HA) as filler. The influence of clay content on the morphological, thermal and dielectric properties of the polymer composite nanofiber was investigated comprehensively to address the material characteristics of the developed system. The surface structure analysis and contact angle measurements of the electrospun composite nanofibers confirms the change in surface roughness and wettability when the fillers are added to the polymer. The porosity of the composite electrospun nanofiber membrane was found to be 85% with an oil adsorption capacity of 97% and water permeability of 6265 L/m2 h. Furthermore, the asymmetric wettability-driven oil/water emulsion separation abilities of the as-synthesized membranes shows that the separation efficiency of the composite fiber membrane is 10% improved compared to that of the neat fiber membrane, with improved separation time.
Stimuli-Responsive Zinc (II) Coordination Polymers: A Novel Platform for Supramolecular Chromic Smart Tools
Authors: Diana Rosita , Caruso Ugo , Panunzi Barbara
Published: October 2021

The unique role of the zinc (II) cation prompted us to cut a cross-section of the large and complex topic of the stimuli-responsive coordination polymers (CPs). Due to its flexible coordination environment and geometries, easiness of coordination–decoordination equilibria, “optically innocent” ability to “clip” the ligands in emissive architectures, non-toxicity and sustainability, the zinc (II) cation is a good candidate for building supramolecular smart tools. The review summarizes the recent achievements of zinc-based CPs as stimuli-responsive materials able to provide a chromic response. An overview of the past five years has been organised, encompassing 1, 2 and 3D responsive zinc-based CPs; specifically zinc-based metallorganic frameworks and zinc-based nanosized polymeric probes. The most relevant examples were collected following a consequential and progressive approach, referring to the structure–responsiveness relationship, the sensing mechanisms, the analytes and/or parameters detected. Finally, applications of highly bioengineered Zn-CPs for advanced imaging technique have been discussed.
Non-Isothermal Crystallization Kinetics of Poly(ethylene glycol) and Poly(ethylene glycol)-B-Poly(ε-caprolactone) by Flash DSC Analysis
Authors: Li Xiaodong , Zou Meishuai , Lei Lisha , Xi Longhao
Published: October 2021

The non-isothermal crystallization behaviors of poly (ethylene glycol) (PEG) and poly (ethylene glycol)-b-poly(ε-caprolactone) (PEG-PCL) were investigated through a commercially available chip-calorimeter Flash DSC2+. The non-isothermal crystallization data under different cooling rates were analyzed by the Ozawa model, modified Avrami model, and Mo model. The results of the non-isothermal crystallization showed that the PCL block crystallized first, followed by the crystallization of the PEG block when the cooling rate was 50–200 K/s. However, only the PEG block can crystallize when the cooling rate is 300–600 K/s. The crystallization of PEG-PCL is completely inhibited when the cooling rate is 1000 K/s. The modified Avrami and Ozawa models were found to describe the non-isothermal crystallization processes well. The growth methods of PEG and PEG-PCL are both three-dimensional spherulitic growth. The Mo model shows that the crystallization rate of PEG is greater than that of PEG-PCL.
Polyamidoamines Derived from Natural α-Amino Acids as Effective Flame Retardants for Cotton
Authors: Beduini Alessandro , Carosio Federico , Ferruti Paolo , Ranucci Elisabetta , Alongi Jenny
Published: October 2021

In this paper, bioinspired polyamidoamines (PAAs) were synthesized from N,N′-methylenebisacrylamide and nine natural α-amino acids: L-alanine, L-valine, L-leucine (M-LEU), L-histidine, L-serine, L-asparagine, L-glutamine (M-GLN), L-aspartic acid and L-glutamic acid (M-GLU) and their performance as flame retardants (FRs) for cotton were determined. The aim was to ascertain if the ability to protect cotton from fire by the process of intumescing, previously found for the glycine-derived M-GLY, was a general feature of α-amino acid-derived PAAs. None of the PAAs ignited by flame impingement, apart from M-LEU, which burned for a few seconds leaving 93% of residue. All of them formed carbon- and oxygen-rich, porous chars with a graphitic structure in the air at 350 °C, as revealed by X-ray photoelectron spectroscopy. All samples were tested as FRs for cotton by horizontal flame spread tests. At a 5% add-on, M-GLU and M-GLN extinguished the flame. The same results were obtained with all the other PAAs at a 7% add-on. The α-amino acid residues influenced the FR performance. The most effective were those that, by heating, were most suitable for producing thermally stable cyclic aromatic structures. All PAA-treated cotton samples, even when burning, left significant residues, which, according to scanning electron microscopy analysis, maintained the original cotton texture.
Mass-Synthesized Solution-Processable Polyimide Gate Dielectrics for Electrically Stable Operating OFETs and Integrated Circuits
Authors: Wang Rixuan , Lee Joonjung , Hong Jisu , Kwon Hyeok-jin , Ye Heqing , Park Juhyun , Park Chan Eon , Kim Joon Ho , Choi Hyun Ho , Eom Kyuyoung , Kim Se Hyun
Published: October 2021

Polyimides (PIs) are widely utilized polymeric materials for high-temperature plastics, adhesives, dielectrics, nonlinear optical materials, flexible hard-coating films, and substrates for flexible electronics. PIs can be facilely mass-produced through factory methods, so the industrial application value is limitless. Herein, we synthesized a typical poly(amic acid) (PAA) precursor-based solution through an industrialized reactor for mass production and applied the prepared solution to form thin films of PI using thermal imidization. The deposited PI thin films were successfully applied as gate dielectrics for organic field-effect transistors (OFETs). The PI layers showed suitable characteristics for dielectrics, such as a smooth surface, low leakage current density, uniform dielectric constant (k) values regardless of frequency, and compatibility with organic semiconductors. Utilizing this PI layer, we were able to fabricate electrically stable operated OFETs, which exhibited a threshold voltage shift lower than 1 V under bias-stress conditions and a field-effect mobility of 4.29 cm2 V−1 s−1. Moreover, integrated logic gates were manufactured using these well-operated OFETs and displayed suitable operation behavior.
Reusable Ag@TiO2-Based Photocatalytic Nanocomposite Membranes for Solar Degradation of Contaminants of Emerging Concern
Authors: Aoudjit Lamine , Salazar Hugo , Zioui Djamila , Sebti Aicha , Martins Pedro Manuel , Lanceros-Mendez Senentxu
Published: October 2021

Two significant limitations of using TiO2 nanoparticles for water treatment applications are reduced photocatalytic activity under visible radiation and difficulty recovering the particles after use. In this study, round-shaped Ag@TiO2 nanocomposites with a ≈21 nm diameter and a bandgap energy of 2.8 eV were synthesised by a deposition-precipitation method. These nanocomposites were immobilised into a porous poly (vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) matrix and well-distributed within the pores. The photocatalytic activity of Ag@TiO2/PVDF-HFP against metronidazole (MNZ) under solar radiation was evaluated. Further, an adaptive neuro-fuzzy inference system (ANFIS) was applied to predict the effect of four independent variables, including initial pollutant concentration, pH, light irradiation intensity, and reaction time, on the photocatalytic performance of the composite membrane on MNZ degradation. The 10% Ag@TiO2/PVDF-HFP composite membrane showed a maximum removal efficiency of 100% after 5 h under solar radiation. After three use cycles, this efficiency remained practically constant, demonstrating the membranes’ reusability and suitability for water remediation applications.
Experimental Investigation of BFRP Tendons under Monotonic and Hysteretic Loadings
Authors: Wang Yongwei , Zhou Zhen , Wei Yang , Zhu Dongping
Published: October 2021

Basalt fiber reinforced polymers (BFRPs) have been widely used in structures because of their high strength and light weight advantages. The previous research neglected the effect of the bonded anchor which led to overestimated performances of the BFRP tendons. In this study, experiments on the monotonic and hysteretic behaviors were conducted to analyze the mechanics of the BFRP tendons with bonded anchors. After considering the influences of the loading rates and initial prestressed displacements, the anchor colloidal deformations of the BFRP systems were measured and regressed. The results showed that the bearing and elongation capacities of the BFRP tendons, which exceed 3.3% and 140 kN, respectively, were independent of the loading rate and initial prestressed displacement under the monotonic and hysteretic loadings. The colloidal deformations, which accounted for about 20% of the whole deformation of the BFRP tendons, cannot be neglected in the predicted responses of the BFRP tendons. The regressed formulas of the anchor colloidal deformation could effectively anticipate the monotonic and hysteretic responses of the BFRP tendons. Therefore, the BFRP tendons with relatively stable mechanical properties are suitable for further practical application.
Oxidative Depolymerization of Alkaline Lignin from Pinus Pinaster by Oxygen and Air for Value-Added Bio-Sourced Synthons
Authors: Camus Martin , Condassamy Olivia , Ham-Pichavant Frédérique , Michaud Christelle , Mastroianni Sergio , Mignani Gérard , Grau Etienne , Cramail Henri , Grelier Stéphane
Published: October 2021

In this work, an efficient 3-step process targeting the chemical modification and purification of lignin oligomers from industrial alkaline lignin is described. The oxidative depolymerization process of alkaline lignin with O2 or Air pressure, without use of metal catalyst, led to the production of two fractions of lignin oligomers named ‘precipitated lignin’ and ‘hydrosoluble lignin’ with 40% and 60% yield, respectively. These fractions were characterized with a wide range of methods including NMR spectroscopy (31P, 2D-HSQC), SEC (in basic media), FTIR. NMR analyses revealed the presence of carboxylic acid functions at a ratio of 1.80 mmol/g and 2.80 mmol/g for the precipitated and hydrosoluble lignin, respectively, values much higher than what is generally found in native lignin (between 0.2 and 0.5 mmol/g). SEC analyses revealed the formation of low molar masses for the precipitated (2200 g/mol) and hydrosoluble fractions (1500 g/mol) in contrast to the alkaline lignin (3900 g/mol). It is worth noting that the hydrosoluble fraction of lignin is soluble in water at any pH. Both processes (oxygen and air) were successfully scaled up and showed similar results in terms of yield and functionalization.
Facile Modification of NF Membrane by Multi-Layer Deposition of Polyelectrolytes for Enhanced Fouling Resistance
Authors: Baig Umair , Waheed Abdul , Salih Hassan A. , Matin Asif , Alshami Ali , Aljundi Isam H.
Published: October 2021

Fouling not only deteriorates the membrane structure but also compromises the quality of the permeate and has deleterious consequences on the membrane operation. In the current study, a commercial thin film composite nanofiltration membrane (NF90) was modified by sequentially depositing oppositely charged polycation (poly(allylamine hydrochloride)) and polyanion (poly(acrylic acid)) polyelectrolytes using the layer-by-layer assembly method. The water contact angle was decreased by ~10° after the coating process, indicating increased hydrophilicity. The surface roughness of the prepared membranes decreased from 380 nm (M-0) to 306 nm (M-10) and 366 nm (M-20). M-10 membrane showed the highest permeate flux of 120 L m−2 h−1 with a salt rejection of >98% for MgSO4 and NaCl. The fabricated membranes M-20 and M-30 showed 15% improvement in fouling resistance and maintained the initial permeate flux longer than the pristine membrane.
Construction of Self-Healing Disulfide-Linked Silicone Elastomers by Thiol Oxidation Coupling Reaction
Authors: Huang Yanhua , Yan Jianpan , Wang Dengxu , Feng Shengyu , Zhou Chuanjian
Published: October 2021

Developing self-healing silicone elastomers are highly significant because of their promising applications. Herein, we present novel self-healing disulfide-linked silicone elastomers (SEs) based on thiol-terminated sulfur-containing heterochain polysiloxanes (P-SHs) and three thiol-containing crosslinkers, including pentaerythritol tetrakis(β-mercaptopropionate) (PETMP), octa(3-mercaptopropyl)silsesquioxane (POSS-SH), and poly[(mercaptopropyl)methylsiloxane] (PMMS), via the thiol oxidation coupling reactions. The construction of these SEs can rapidly proceed at room temperature. The effects of crosslinker species and amounts on the formability and mechanical properties were investigated. The silicone elastomers can be self-healed by heating at 150 °C for 2 h or under UV radiation for 30 min after cutting them into pieces and the self-healing efficiency is >70%. Moreover, they can be utilized as adhesives for bonding glass sheets, which can hold a 200 g weight. The bonding is reversible and can repeatedly proceed many times, indicating that these materials can promisingly be applied as reversible adhesives. These results indicate that a thiol oxidation coupling reaction is a simple and effective strategy for the construction of self-healing disulfide-linked elastomers. Under this strategy, more disulfide-linked organic elastomers with self-healing properties can be designed and constructed and their applications can be further explored.
Molecular Structure Effect of a Self-Assembled Monolayer on Thermal Resistance across an Interface
Authors: Song Lijian , Zhang Youchen , Yang Weimin , Tan Jing , Cheng Lisheng
Published: October 2021

Understanding heat transfer across an interface is essential to a variety of applications, including thermal energy storage systems. Recent studies have shown that introducing a self-assembled monolayer (SAM) can decrease thermal resistance between solid and fluid. However, the effects of the molecular structure of SAM on interfacial thermal resistance (ITR) are still unclear. Using the gold–SAM/PEG system as a model, we performed nonequilibrium molecular dynamics simulations to calculate the ITR between the PEG and gold. We found that increasing the SAM angle value from 100° to 150° could decrease ITR from 140.85 × 10−9 to 113.79 × 10−9 m2 K/W owing to penetration of PEG into SAM chains, which promoted thermal transport across the interface. Moreover, a strong dependence of ITR on bond strength was also observed. When the SAM bond strength increased from 2 to 640 kcal⋅mol−1Å−2, ITR first decreased from 106.88 × 10−9 to 102.69 × 10−9 m2 K/W and then increased to 123.02 × 10−9 m2 K/W until reaching a steady state. The minimum ITR was obtained when the bond strength of SAM was close to that of PEG melt. The matching vibrational spectra facilitated the thermal transport between SAM chains and PEG. This work provides helpful information regarding the optimized design of SAM to enhance interfacial thermal transport.
Biotechnological Applications of Polymeric Nanofiber Platforms Loaded with Diverse Bioactive Materials
Authors: El-Aassar M. R. , Ibrahim Omar M. , Al-Oanzi Ziad H.
Published: October 2021

This review article highlights the critical research and formative works relating to nanofiber composites loaded with bioactive materials for diverse applications, and discusses the recent research on the use of electrospun nanofiber incorporating bioactive compounds such as essential oils, herbal bioactive components, plant extracts, and metallic nanoparticles. Inevitably, with the common advantages of bioactive components and polymer nanofibers, electrospun nanofibers containing bioactive components have attracted intense interests for their applications in biomedicine and cancer treatment. Many studies have only concentrated on the production and performance of electrospun nanofiber loaded with bioactive components; in this regard, the features of different types of electrospun nanofiber incorporating a wide variety of bioactive compounds and their developing trends are summarized and assessed in the present article, as is the feasible use of nanofiber technology to produce products on an industrial scale in different applications.
Screening of Lignocellulolytic Enzyme Activities in Fungal Species and Sequential Solid-State and Submerged Cultivation for the Production of Enzyme Cocktails
Authors: Marđetko Nenad , Trontel Antonija , Novak Mario , Pavlečić Mladen , Ljubas Blanka Didak , Grubišić Marina , Tominac Vlatka Petravić , Ludwig Roland , Šantek Božidar
Published: October 2021

Various fungal species can degrade lignocellulolytic materials with their enzyme cocktails composed of cellulolytic and lignolytic enzymes. In this work, seven fungal species (Mucor indicus DSM 2185, Paecilomyces variotii CBS 372.70, Myceliophthora thermophila CBS 663.74, Thielavia terrestris CBS 456.75, Botryosphaeria dothidea JCM 2738, Fusarium oxysporum f.sp. langenariae JCM 9293, and Fusarium verticillioides JCM 23107) and four nutrient media were used in the screening for effective lignocellulose degrading enzymes. From the seven tested fungi, F. oxysporum and F. verticilliodes, along with nutrient medium 4, were selected as the best medium and producers of lignocellulolytic enzymes based on the determined xylanase (>4 U mg−1) and glucanase activity (≈2 U mg−1). Nutrient medium 4 supplemented with pretreated corn cobs was used in the production of lignocellulolytic enzymes by sequential solid-state and submerged cultivation of F. oxysporum, F. verticilliodes, and a mixed culture of both strains. F. oxysporum showed 6 times higher exoglucanase activity (3.33 U mg−1) after 5 days of cultivation in comparison with F. verticillioides (0.55 U mg−1). F. oxysporum also showed 2 times more endoglucanase activity (0.33 U mg−1). The mixed culture cultivation showed similar endo- and exoglucanase activities compared to F. oxysporum (0.35 U mg−1; 7.84 U mg−1). Maximum xylanase activity was achieved after 7 days of cultivation of F. verticilliodes (≈16 U mg−1), while F. oxysporum showed maximum activity after 9 days that was around 2 times lower compared to that of F. verticilliodes. The mixed culture achieved maximum xylanase activity after only 4 days, but the specific activity was similar to activities observed for F. oxysporum. It can be concluded that both fungal strains can be used as producers of enzyme cocktails for the degradation of lignocellulose containing raw materials, and that corn cobs can be used as an inducer for enzyme production.
Comprehensive Optimization of the Dispersion of Mixing Particles in an Inert-Particle Spouted-Bed Reactor (IPSBR) System
Authors: Mohammad Ameera F. , Mourad Aya A.-H. I. , Al-Marzouqi Ali H. , El-Naas Muftah H. , Bruggen Bart Van der , Al-Marzouqi Mohamed H. , Alnaimat Fadi , Al Musharfy Mohamed
Published: October 2021

Effective gas dispersion and liquid mixing are significant parameters in the design of an inert-particle spouted-bed reactor (IPSBR) system. Solid particles can be used to ensure good mixing and an efficient rate of mass and heat transfer between the gas and liquid. In this study, computational fluid dynamics (CFD) coupled with the discrete phase model (DPM) were developed to investigate the effect of the feed gas velocity (0.5–1.5 m/s), orifice diameter (0.001–0.005 m), gas head (0.15–0.35 m), particle diameter (0.009–0.0225 m), and mixing-particle-to-reactor-volume fraction (2.0–10.0 vol.%) on the solid mass concentration, average solid velocity, and average solid volume fraction in the upper, middle, and conical regions of the reactor. Statistical analysis was performed using a second-order response surface methodology (RSM) with central composite design (CCD) to obtain the optimal operating conditions. Selected parameters were optimized to maximize the responses in the middle and upper regions, and minimize them in the conical region. Such conditions produced a high interfacial area and fewer dead zones owing to good particle dispersion. The optimal process variables were feed gas velocity of 1.5 m/s, orifice diameter of 0.001 m, gas head of 0.2025 m, a particle diameter of 0.01 m, and a particle load of 0.02 kg. The minimum average air velocity and maximum air volume fraction were observed under the same operating conditions. This confirmed the novelty of the reactor, which could work at a high feed gas velocity while maintaining a high residence time and gas volume fraction.
Synthesis of ZnO-CuO and ZnO-Co3O4 Materials with Three-Dimensionally Ordered Macroporous Structure and Its H2S Removal Performance at Low-Temperature
Authors: Yu Tao , Chen Zhuo , Wang Yundong , Xu Jianhong
Published: October 2021

H2S is a common but hazardous impurity in syngas, biogas, or natural gas. For some advanced power generation technologies, such as integrated gasification combined cycle (IGCC), solid oxide fuel cells, H2S content needs to be reduced to an acceptable level. In this work, a series of highly porous Zn-Cu and Zn-Co composites with three-dimensionally ordered macropores (3DOM) structure were synthesized via the colloidal crystal template method and used to remove H2S at 150 °C and one atm. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen adsorption studies, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) were carried out to analyze the fresh and spent adsorbents. The results show that all the adsorbents possess well-ordered macropores, a large surface area, and a highly dispersed active phase. The relative content of Zn and (Cu or Co) has a significant influence on the desulfurization performance of adsorbents. The addition of CuO significantly increases the sulfur capacity and 3DOM-Zn0.5Cu0.5 shows the largest sulfur capacity of all the adsorbents, reaching up to 102.5 mg/g. The multiple adsorption/regeneration cycles of 3DOM-Zn0.5Cu0.5 and 3DOM-Zn0.5Co0.5 indicate that the as-prepared adsorbents are stable, and the sulfur capacity can still exceed 65% of the fresh adsorbents after six cycles.
Comparison of Sliding and Overset Mesh Techniques in the Simulation of a Vertical Axis Turbine for Hydrokinetic Applications
Authors: Lopez Mejia Omar D. , Mejia Oscar E. , Escorcia Karol M. , Suarez Fabian , Laín Santiago
Published: October 2021

The application of Computational Fluid Dynamics (CFD) to energy-related problems has increased in the last decades in both renewable and conventional energy conversion processes. In recent years, the application of CFD in the study of hydraulic, marine, tidal, and hydrokinetic turbines has focused on the understanding of the details of the complex turbulent flow and also in improving the prediction of the performance of these devices. There are several complexities involved in the simulation of Vertical Axis Turbine (VAT) for hydrokinetic applications. One of them is the necessity of a dynamic mesh model. Typically, the model used in the simulation of these devices is the sliding mesh technique, but in recent years the fast development of the overset (also known as chimera) mesh technique has caught the attention of the academic community. In the present paper, a comparison between these two techniques is done in order to establish their advantages and disadvantages in the two-dimensional simulation of vertical axis turbines. The comparison was done not only for the prediction of performance parameters of the turbine but also for the capabilities of the models to capture complex flow phenomena in these devices and computational costs.
Design of an IOTA Tangle-Based Intelligent Food Safety Service Platform for Bubble Tea
Authors: Ku Hao-Hsiang , Chi Ching-Ho , Ling Min-Pei
Published: October 2021

Many food safety incidents have occurred in the world in the past 20 years, causing major threats and harm to human life and health. Each country or region has established different food safety management systems (FSMSs) in response, to increase food safety and to reduce food safety risks. Hence, it is important to develop an FSMS service platform with convenience, consistency, effectiveness, scalability, and lightweight computing. The aim of this study is to design and propose an IOTA Tangle-based intelligent food safety service platform for bubble tea—called IF4BT—which modularizes and integrates hazard analysis and critical control point (HACCP) principles to increase data transparency. The deep learning inference engine is based on long short-term memory and Siamese networks to check and extract significant rare data of high-risk factors, exception factors, and noises, depending on daily check and audit. IF4BT can ensure the correctness of the information of food manufacturers, so as to increase food safety and to reduce food safety issues such as allergen cross-contamination, food expiration, food defense, and food fraud.
Modification of SiO2, ZnO, Fe2O3 and TiN Films by Electronic Excitation under High Energy Ion Impact
Authors: Matsunami Noriaki , Sataka Masao , Okayasu Satoru , Tsuchiya Bun
Published: October 2021

It has been known that the modification of non-metallic solid materials (oxides, nitrides, etc.), e.g., the formation of tracks, sputtering representing atomic displacement near the surface and lattice disordering are induced by electronic excitation under high-energy ion impact. We have investigated lattice disordering by the X-ray diffraction (XRD) of SiO2, ZnO, Fe2O3 and TiN films and have also measured the sputtering yields of TiN for a comparison of lattice disordering with sputtering. We find that both the degradation of the XRD intensity per unit ion fluence and the sputtering yields follow the power-law of the electronic stopping power and that these exponents are larger than unity. The exponents for the XRD degradation and sputtering are found to be comparable. These results imply that similar mechanisms are responsible for the lattice disordering and electronic sputtering. A mechanism of electron–lattice coupling, i.e., the energy transfer from the electronic system into the lattice, is discussed based on a crude estimation of atomic displacement due to Coulomb repulsion during the short neutralization time (~fs) in the ionized region. The bandgap scheme or exciton model is examined.
The Source Value of Arabic Typikon-Manuscripts as Testimonials for the Byzantinization of the Melkites
Authors: Lüstraeten Martin
Published: October 2021

With the expansion of Islam, the patriarchates of Antioch, Jerusalem, and Alexandria were divided from the Byzantine Empire. The Orthodox Christians there still defined themselves as Byzantine Orthodox and began to adapt their liturgical customs by adopting Byzantine liturgical books. When Greek was not understood any longer, they began to translate and copy their liturgical books, thereby creating their own branch of tradition, which is marked by multilingualism, reception of their own Bible tradition as well as the exclusion of “neo-martyrs” from their calendar of saints.
Tracing the Life of a Buddhist Literary Apologia: Steps in Preparation for the Study and Translation of Sokdokpa’s Thunder of Definitive Meaning
Authors: Gentry James Duncan
Published: October 2021

This article discusses Buddhist apologetics in Tibet by examining the formation, revision, and reception of the most renowned literary apologia ever written in defense of the Old School of Tibetan Buddhism: Sokdokpa Lodrö Gyeltsen’s early 17th-century magnum opus the Thunder of Definitive Meaning. It reconstructs in broad strokes the history of the Thunder’s reception from the early 17th century to the present and relates this to details in different versions of the Thunder and its addendum to shed light on the process by which this work was composed and edited. By considering this work’s peculiar context of production and history of reception alongside passages it presents revealing how it was conceived and revised, this analysis aims to prepare the ground for its study and translation. In so doing, this discussion attempts to show how a broadly historical approach can work in tandem with a fine-grained philological approach to yield fresh insights into the production and reception of Buddhist literary works that have important ramifications for their understanding and translation.
The Adaptation and Development of the Proclean Notion of Κατάβασις: From Proclus to Maximus the Confessor
Authors: Woo Kyeongyoon
Published: October 2021

This paper examines the impact of Proclus’ notion of divine descent, i.e., κατάβασις, on the formation of core theological doctrines in Pseudo-Dionysius and Maximus the Confessor. The notion of κατάβασις was originally employed by pagan Proclus to explain the downward providence of gods toward humans, emphasizing the dominant role of gods for human perfection. In his exegesis on Alcibiades I, Proclus identified Socrates as the incarnation of divine providence, a divinely inspired lover in charge of Alcibiades’ conversion to philosophical life. Pseudo-Dionysius adapted the Proclean notion of κατάβασις by supplementing it with the Christian notion of God’s ecstatic love, understood as God’s providential act toward His creation. In the Celestial Hierarchy and Ecclesiastical Hierarchy, Dionysius endeavored to reveal the reciprocal-ecstatic union between God and humans made possible by His ecstatic κατάβασις during the liturgy. Maximus adapted and further developed the Dionysian notion of κατάβασις. While stressing the crucial role of the κατάβασις for human salvation, he gave it a new meaning by synthesizing it in the context of his anthropology, which stressed the holistic transformation of the human body and soul as a result of the divine descent.
Greenspace to Meet People’s Demand: A Case Study of Beijing in 2005 and 2015
Authors: Chen Zhanghao , Huang Ganlin
Published: October 2021

Urban greenspace provides essential benefits and often depends on its distribution and spatial relationship with residents. Many cities set ambitious goals to increase the coverage of greenspace. In addition, to increase the total amount of greenspace, spatial patterns of greenspace supply and demand also need to be taken into account to make sure its ecosystem services can reach the residents. While previous research has examined greenspace distribution, its association with various ecosystem services, and its spatial relationship with residents’ socioeconomic characteristics, relatively few studies have considered the spatial pattern of greenspace demand to assess its supply change over time. To fill this gap, we evaluated the greenspace change of Beijing between 2005 and 2015 using 2.5 m and 0.5 m high resolution remote sensing images. We first identified all of the greenspace changes, then evaluated the improvement of greenspace that was accessible to residents, and finally, we examined whether such improvement met different levels of demand estimated by neighborhood population, age structure, and economic status. The results showed a net increase of 1472 ha (7.8%) from 2005 to 2015. On average, percent greenspace within 500 m of the neighborhood boundary increased from 21% to 24%. Areas with low greenspace supply had a significantly higher increase. The standard deviation reduced from 8% to 7%, which indicated a smaller disparity of accessible greenspace. However, results showed that greenspace increase had little variation among neighborhoods with different demand levels. Our findings indicated that the greening efforts improved spatial distribution and reduced inequality in accessibility but failed to address different demand levels among neighborhoods. Furthermore, we identified neighborhoods with low supply/high demand and that lost greenspace between 2005–2015. These neighborhoods need to be given attention in future greening projects.
PEMCNet: An Efficient Multi-Scale Point Feature Fusion Network for 3D LiDAR Point Cloud Classification
Authors: Zhao Genping , Zhang Weiguang , Peng Yeping , Wu Heng , Wang Zhuowei , Cheng Lianglun
Published: October 2021

Point cloud classification plays a significant role in Light Detection and Ranging (LiDAR) applications. However, most available multi-scale feature learning networks for large-scale 3D LiDAR point cloud classification tasks are time-consuming. In this paper, an efficient deep neural architecture denoted as Point Expanded Multi-scale Convolutional Network (PEMCNet) is developed to accurately classify the 3D LiDAR point cloud. Different from traditional networks for point cloud processing, PEMCNet includes successive Point Expanded Grouping (PEG) units and Absolute and Relative Spatial Embedding (ARSE) units for representative point feature learning. The PEG unit enables us to progressively increase the receptive field for each observed point and aggregate the feature of a point cloud at different scales but without increasing computation. The ARSE unit following the PEG unit furthermore realizes representative encoding of points relationship, which effectively preserves the geometric details between points. We evaluate our method on both public datasets (the Urban Semantic 3D (US3D) dataset and Semantic3D benchmark dataset) and our new collected Unmanned Aerial Vehicle (UAV) based LiDAR point cloud data of the campus of Guangdong University of Technology. In comparison with four available state-of-the-art methods, our methods ranked first place regarding both efficiency and accuracy. It was observed on the public datasets that with a 2% increase in classification accuracy, over 26% improvement of efficiency was achieved at the same time compared to the second efficient method. Its potential value is also tested on the newly collected point cloud data with over 91% of classification accuracy and 154 ms of processing time.
Target Detection in High-Resolution SAR Image via Iterating Outliers and Recursing Saliency Depth
Authors: Cui Zongyong , Qin Yi , Zhong Yating , Cao Zongjie , Yang Haiyi
Published: October 2021

In dealing with the problem of target detection in high-resolution Synthetic Aperture Radar (SAR) images, segmenting before detecting is the most commonly used approach. After the image is segmented by the superpixel method, the segmented area is usually a mixture of target and background, but the existing regional feature model does not take this into account, and cannot accurately reflect the features of the SAR image. Therefore, we propose a target detection method based on iterative outliers and recursive saliency depth. At first, we use the conditional entropy to model the features of the superpixel region, which is more in line with the actual SAR image features. Then, through iterative anomaly detection, we achieve effective background selection and detection threshold design. After that, recursing saliency depth is used to enhance the effective outliers and suppress the background false alarm to realize the correction of superpixel saliency value. Finally, the local graph model is used to optimize the detection results. Compared with Constant False Alarm Rate (CFAR) and Weighted Information Entropy (WIE) methods, the results show that our method has better performance and is more in line with the actual situation.
An Improved Adaptive Kalman Filter for a Single Frequency GNSS/MEMS-IMU/Odometer Integrated Navigation Module
Authors: Yan Peihui , Jiang Jinguang , Zhang Fangning , Xie Dongpeng , Wu Jiaji , Zhang Chao , Tang Yanan , Liu Jingnan
Published: October 2021

Aiming at the GNSS receiver vulnerability in challenging urban environments and low power consumption of integrated navigation systems, an improved robust adaptive Kalman filter (IRAKF) algorithm with real-time performance and low computation complexity for single-frequency GNSS/MEMS-IMU/odometer integrated navigation module is proposed. The algorithm obtains the scale factor by the prediction residual, and uses it to adjust the artificially set covariance matrix of the observation vector under different GNSS solution states, so that the covariance matrix of the observation vector changes continuously with the complex scene. Then, the adaptive factor is calculated by the Mahalanobis distance to inflate the state prediction covariance matrix. In addition, the one-step prediction Kalman filter is introduced to reduce the computational complexity of the algorithm. The performance of the algorithm is verified by vehicle experiments in the challenging urban environments. Experiments show that the algorithm can effectively weaken the effects of abnormal model deviations and outliers in the measurements and improve the positioning accuracy of real-time integrated navigation. It can meet the requirements of low power consumption real-time vehicle navigation applications in the complex urban environment.
Estimating Historically Cleared and Forested Land in Massachusetts, USA, Using Airborne LiDAR and Archival Records
Authors: Johnson Katharine M. , Ouimet William B. , Dow Samantha , Haverfield Cheyenne
Published: October 2021

In the northeastern United States, widespread deforestation occurred during the 17–19th centuries as a result of Euro-American agricultural activity. In the late 19th and early 20th centuries, much of this agricultural landscape was reforested as the region experienced industrialization and farmland became abandoned. Many previous studies have addressed these landscape changes, but the primary method for estimating the amount and distribution of cleared and forested land during this time period has been using archival records. This study estimates areas of cleared and forested land using historical land use features extracted from airborne LiDAR data and compares these estimates to those from 19th century archival maps and agricultural census records for several towns in Massachusetts, a state in the northeastern United States. Results expand on previous studies in adjacent areas, and demonstrate that features representative of historical deforestation identified in LiDAR data can be reliably used as a proxy to estimate the spatial extents and area of cleared and forested land in Massachusetts and elsewhere in the northeastern United States. Results also demonstrate limitations to this methodology which can be mitigated through an understanding of the surficial geology of the region as well as sources of error in archival materials.