bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Laser Spot Size on the Mechanical Properties of AISI 420 Stainless Steel Fabricated by Selective Laser Melting
Authors: Yang Xi-Huai , Jiang Chong-Ming , Ho Jeng-Rong , Tung Pi-Cheng , Lin Chih-Kuang
Published: August 2021

The purpose of this study is to investigate the effects of laser spot size on the mechanical properties of AISI 420 stainless steel, fabricated by selective laser melting (SLM), process. Tensile specimens were built directly via the SLM process, using various laser spot diameters, namely 0.1, 0.2, 0.3, and 0.4 mm. The corresponding volumetric energy density (EV) is 80, 40, 26.7, and 20 J/mm3, respectively. Experimental results indicate that laser spot size is an important process parameter and has significant effects on the surface roughness, hardness, density, tensile strength, and microstructure of the SLM AISI 420 builds. A large laser spot with low volumetric energy density results in balling, un-overlapped defects, a large re-heated zone, and a large sub-grain size. As a result, SLM specimens fabricated by the largest laser spot diameter of 0.4 mm exhibit the roughest surface, lowest densification, and lowest ultimate tensile strength. To ensure complete melting of the powder and melt pool stability, EV of 80 J/mm3 proves to be a suitable laser energy density value for the given SLM processing and material system.
Assessment of Long Lived Isotopes in Alkali-Silica Resistant Concrete Designed for Nuclear Installations
Authors: Jóźwiak-Niedźwiedzka Daria , Gméling Katalin , Antolik Aneta , Dziedzic Kinga , Glinicki Michał A.
Published: August 2021

The design of concrete for radiation shielding structures is principally based on the selection of materials of adequate elemental composition and mix proportioning to achieve the long-term durability in nuclear environment. Concrete elements may become radioactive through exposure to neutron radiation from the nuclear reactor. A selection of constituent materials of greatly reduced content of long-lived residual radioisotopes would reduce the volume of low-level waste during plant decommissioning. The objective of this investigation is an assessment of trace elements with a large activation cross section in concrete constituents and simultaneous evaluation of susceptibility of concrete to detrimental alkali-silica reaction. Two isotopes 60Co and 152Eu were chosen as the dominant long-lived residual radioisotopes and evaluated using neutron activation analysis. The influence of selected mineral aggregates on the expansion due to alkali-silica reaction was tested. The content of 60Co and 152Eu activated by neutron radiation in fine and coarse aggregates, as well as in four types of Portland cement, is presented and discussed in respect to the chemical composition and rock origin. Conflicting results were obtained for quartzite coarse aggregate and siliceous river sand that, despite a low content, 60Co and 152Eu exhibited a high susceptibility to alkali-silica reaction in Portland cement concrete. The obtained results facilitate a multicriteria selection of constituents for radiation-shielding concrete.
Phase Formation during Heating of Amorphous Nickel-Based BNi-3 for Joining of Dissimilar Cobalt-Based Superalloys
Authors: Naalchian Mojtaba , Kasiri-Asgarani Masoud , Shamanian Morteza , Bakhtiari Reza , Bakhsheshi-Rad Hamid Reza , Berto Filippo , Das Oisik
Published: August 2021

Phase transformations and the melting range of the interlayer BNi-3 were investigated by differential scanning calorimetry, which showed three stages of crystallization during heating. There were three exothermic peaks that indicated crystallization in the solid state. The cobalt-based X-45 and FSX-414 superalloys were bonded with interlayer BNi-3 at a constant holding time of 10 min with bonding temperatures of 1010, 1050, 1100, and 1150 °C using a vacuum diffusion brazing process. Examination of microstructural changes in the base metals with light microscopy and scanning electron microscopy coupled with X-ray spectroscopy based on the energy distribution showed that increasing temperature caused a solidification mode, such that the bonding centerline at 1010 °C/10 min included a γ-solid solution, Ni3B, Ni6Si2B, and Ni3Si. The athermally solidified zone of the transient liquid phase (TLP)-bonded sample at 1050 °C/10 min involved a γ-solid solution, Ni3B, CrB, Ni6Si2B, and Ni3Si. Finally, isothermal solidification was completed within 10 min at 1150 °C. The diffusion-affected zones on both sides had three distinct zones: a coarse block precipitation zone, a fine and needle-like mixed-precipitation zone, and a needle-like precipitation zone. By increasing the bonding temperature, the diffusion-affected zone became wider and led to dissolution.
Analytical Solution of Laterally Loaded Free-Head Long Piles in Elasto-Plastic Cohesive Soils
Authors: Abd-Elhamed Ayman
Published: August 2021

This research study presents a closed form solution of responses of laterally loaded long piles embedded on cohesive soils with a constant subgrade modulus. The surrounding soil medium is modelled as elastic-perfectly plastic. The closed form solution is derived by solving the governing differential equation of the pile–soil system. The most popular numerical computation software package MATLAB is utilized for the implementation of solutions. The provided analytical method reliably calculates the pile head deflection and bending moment required for engineering design purposes. Results are discussed and verified with solutions of an equivalent three-dimensional finite element (FE) model developed using ANSYS software. It was concluded that the proposed analytical model could efficiently provide the exact solution of embedded piles in elasto-plastic cohesive soil under lateral loads.
Selective Laser Melting of Ti6Al4V-2%Hydroxyapatite Composites: Manufacturing Behavior and Microstructure Evolution
Authors: Jaber Hassanen , Kónya János , Anna Kovács Tünde
Published: August 2021

In this work, selective laser melting of Ti6Al4V (Ti64) and 2 wt.% hydroxyapatite (HA) composites was performed with the purpose of osseointegration enhancement and biological fixation between implants and bone tissue. The microstructural evolution and mechanical properties were analyzed by using X-ray diffraction (XRD), optical microscopy (OM), a scanning electron microscope (SEM) equipped with (EDX) and (EBSD) systems, microhardness, nanoindentation, and tensile testing. The results showed that the Ti64-2%HA composite components exhibited complicated manufacturing behavior, which could be correlated with the decomposition of HA. The microstructure was found to mainly consist of α Ti with a small amount of HA distributed along grain boundaries. Furthermore, the interaction between Ti64 and HA leading to the formation of Ti3P, TixO, P, and CaTiO3 phases, resulted in poor tensile properties, as compared to pure Ti64 components. Conversely, the tensile properties of SLM Ti64-2%HA composite components were significantly higher than human bone reported previously in the literature.
A Personalized Glomerulus Chip Engineered from Stem Cell-Derived Epithelium and Vascular Endothelium
Authors: Roye Yasmin , Bhattacharya Rohan , Mou Xingrui , Zhou Yuhao , Burt Morgan A. , Musah Samira
Published: August 2021

Progress in understanding kidney disease mechanisms and the development of targeted therapeutics have been limited by the lack of functional in vitro models that can closely recapitulate human physiological responses. Organ Chip (or organ-on-a-chip) microfluidic devices provide unique opportunities to overcome some of these challenges given their ability to model the structure and function of tissues and organs in vitro. Previously established organ chip models typically consist of heterogenous cell populations sourced from multiple donors, limiting their applications in patient-specific disease modeling and personalized medicine. In this study, we engineered a personalized glomerulus chip system reconstituted from human induced pluripotent stem (iPS) cell-derived vascular endothelial cells (ECs) and podocytes from a single patient. Our stem cell-derived kidney glomerulus chip successfully mimics the structure and some essential functions of the glomerular filtration barrier. We further modeled glomerular injury in our tissue chips by administering a clinically relevant dose of the chemotherapy drug Adriamycin. The drug disrupts the structural integrity of the endothelium and the podocyte tissue layers, leading to significant albuminuria as observed in patients with glomerulopathies. We anticipate that the personalized glomerulus chip model established in this report could help advance future studies of kidney disease mechanisms and the discovery of personalized therapies. Given the remarkable ability of human iPS cells to differentiate into almost any cell type, this work also provides a blueprint for the establishment of more personalized organ chip and ‘body-on-a-chip’ models in the future.
Design of an FPGA-Based Fuzzy Feedback Controller for Closed-Loop FES in Knee Joint Model
Authors: Noorsal Emilia , Arof Saharul , Yahaya Saiful Zaimy , Hussain Zakaria , Kho Daniel , Mohd Ali Yusnita
Published: August 2021

Functional electrical stimulation (FES) device has been widely used by spinal cord injury (SCI) patients in their rehab exercises to restore motor function to their paralysed muscles. The major challenge of muscle contraction induced by FES is early muscle fatigue due to the open-loop stimulation strategy. To reduce the early muscle fatigue phenomenon, a closed-loop FES system is proposed to track the angle of the limb’s movement and provide an accurate amount of charge according to the desired reference angle. Among the existing feedback controllers, fuzzy logic controller (FLC) has been found to exhibit good control performance in handling complex non-linear systems without developing any complex mathematical model. Recently, there has been considerable interest in the implementation of FLC in hardware embedded systems. Therefore, in this paper, a digital fuzzy feedback controller (FFC) embedded in a field-programmable gate array (FPGA) board was proposed. The digital FFC mainly consists of an analog-to-digital converter (ADC) Data Acquisition and FLC sub-modules. The FFC was designed to monitor and control the progress of knee extension movement by regulating the stimulus pulse width duration to meet the target angle. The knee is expected to extend to a maximum reference angle setting (70°, 40° or 30°) from its normal position of 0° once the stimulus charge is applied to the muscle by the FES device. Initially, the FLC was modelled using MATLAB Simulink. Then, the FLC was hardcoded into digital logic using hardware description language (HDL) Verilog codes. Thereafter, the performance of the digital FLC was tested with a knee extension model using the HDL co-simulation technique in MATLAB Simulink. Finally, for real-time verification, the designed digital FFC was downloaded to the Intel FPGA (DE2-115) board. The digital FFC utilized only 4% of the total FPGA (Cyclone IV E) logic elements (LEs) and required 238 µs to regulate stimulus pulse width data, including 3 µs for the FLC computation. The high processing speed of the digital FFC enables the stimulus pulse width duration to be updated every stimulation cycle. Furthermore, the implemented digital FFC has demonstrated good control performance in accurately controlling the stimulus pulse width duration to reach the desired reference angle with very small overshoot (1.4°) and steady-state error (0.4°). These promising results are very useful for a real-world closed-loop FES application.
A Vacuum-Powered Artificial Muscle Designed for Infant Rehabilitation
Authors: Mendoza Mijaíl Jaén , Gollob Samuel Dutra , Lavado Diego , Koo Bon Ho Brandon , Cruz Segundo , Roche Ellen T. , Vela Emir A.
Published: August 2021

The majority of soft pneumatic actuators for rehabilitation exercises have been designed for adult users. Specifically, there is a paucity of soft rehabilitative devices designed for infants with upper and lower limb motor disabilities. We present a low-profile vacuum-powered artificial muscle (LP-VPAM) with dimensions suitable for infants. The actuator produced a maximum force of 26 N at vacuum pressures of −40 kPa. When implemented in an experimental model of an infant leg in an antagonistic-agonist configuration to measure resultant knee flexion, the actuator generated knee flexion angles of 43° and 61° in the prone and side-lying position, respectively.
Chemometric Analysis of Fatty Acid Composition of Raw Chicken, Beef, and Pork Meat with Plant Extract Addition during Refrigerated Storage
Authors: Muzolf-Panek Małgorzata , Kaczmarek Anna
Published: August 2021

During the shelf-life, meat undergoes a number of processes that negatively affect the quality of the product, including fatty acid composition. The application of various plant extracts in meat could affect the changes of fatty acids during storage. Thus, the aim of this study was to investigate the effect of various spice and herb extracts on fatty acid composition in raw pork, beef, and chicken meat when stored at 4 °C for 13 days. Based on multivariate statistical analysis, two datasets were extracted from each type of meat. One dataset included samples with allspice, bay leaf, black seed, cardamom, caraway, clove, and nutmeg with the high share of total MUFA (monounsaturated fatty acids) in chicken and pork meat and high MUFA and PUFA (polyunsaturated fatty acids) contribution in beef meat after storage. The second dataset included basil, garlic, onion, oregano, rosemary, and thyme with high PUFA share in chicken and pork meat and high SFA (saturated fatty acids) contribution in beef meat. From the regression analysis, a significant effect of time on fatty acid composition in meat was reported. Generally, the rates of fatty acid changes were dependent on the plant extract incorporated into the meat. The most visible effect of plant extracts was obtained in chicken meat. In chicken meat with plant extracts, the rates of SFA and PUFA changes with time were slower compared to the control sample. In summary, the fatty acid composition of intramuscular fat varied during storage, and the addition of plant extracts significantly affected the rate of these changes, which was dependent on the meat matrix.
Metabolic Derangement in Pediatric Patient with Obesity: The Role of Ketogenic Diet as Therapeutic Tool
Authors: Calcaterra Valeria , Verduci Elvira , Pascuzzi Martina Chiara , Magenes Vittoria Carlotta , Fiore Giulia , Di Profio Elisabetta , Tenuta Elisavietta , Bosetti Alessandra , Todisco Carolina Federica , D’Auria Enza , Zuccotti Gianvincenzo
Published: August 2021

Obesity is defined as a condition characterized by an excessive fat accumulation that has negative health consequences. Pediatric obesity is associated with an increased risk for many diseases, including impaired glycemic and lipidic control that may lead to the development of chronic, and potentially disabling, pathologies, such as type 2 diabetes mellitus (T2DM) and cardiovascular events, in adult life. The therapeutic strategy initially starts with interventions that are aimed at changing lifestyle and eating behavior, to prevent, manage, and potentially reverse metabolic disorders. Recently, the ketogenic diet (KD) has been proposed as a promising dietary intervention for the treatment of metabolic and cardiovascular risk factors related to obesity in adults, and a possible beneficial role has also been proposed in children. KD is very low in carbohydrate, high in fat, and moderate to high in protein that may have the potential to promote weight loss and improve lipidic derangement, glycemic control, and insulin sensitivity. In this review, we present metabolic disorders on glycemic and lipidic control in children and adolescents with obesity and indication of KD in pediatrics, discussing the role of KD as a therapeutic tool for metabolic derangement. The results of this review may suggest the validity of KD and the need to further research its potential to address metabolic risk factors in pediatric obesity.
‘Shape-Up’, a Modified Cognitive-Behavioural Community Programme for Weight Management: Real-World Evaluation as an Approach for Delivering Public Health Goals
Authors: Soni Amber , Beeken Rebecca J , McGowan Laura , Lawson Victoria , Chadwick Paul , Croker Helen
Published: August 2021

Obesity is widespread, with serious health consequences; addressing it requires considerable effort at a public health level, incorporating prevention and management along with policies to support implementation. Behavioural weight-management programmes are widely used by public health bodies to address overweight and obesity. Shape-Up is an evidence-based programme combining a structured behavioural intervention (targeting nutrition and physical activity behaviours) within a peer-learning framework. This study was a service-evaluation of Shape-Up, as delivered in Rotherham by a local leisure provider, and included a secondary analysis of data collected in the community by service providers. The RE-AIM (Reach Effectiveness Adoption Implementation Maintenance) framework was used to explore programme effectiveness, implementation, and whom it reached. A total of 141 participants were included. Compared to local demographics, participants were older, at 48.9 (SD 14.47) years, with a lower employment rate (41% employed) and greater proportion female (67% female). Mean BMI was 38.0 (SD 7.54) kg/m2. Mean weight-change between baseline and endpoint (12 weeks, 10 group sessions) was −4.4 (SD 3.38) kg, and degree of weight change was associated with session attendance (F (9, 131) = 6.356, p < 0.0005). There were positive effects on participants’ weight, health-related behaviours, and quality of life. The intervention content (including the focus of nutritional recommendations) and structure were adapted during implementation to better suit national guidelines and local population needs. RE-AIM was found to be a useful framework for evaluating and adapting an existing evidence-based weight management programme in line with local population needs. This could be a more cost-effective approach, compared to developing new programmes, for delivering public health goals relating to obesity, nutrition, and physical activity.
Bioinspired Magnetic Nanochains for Medicine
Authors: Kralj Slavko , Marchesan Silvia
Published: August 2021

Superparamagnetic iron oxide nanoparticles (SPIONs) have been widely used for medicine, both in therapy and diagnosis. Their guided assembly into anisotropic structures, such as nanochains, has recently opened new research avenues; for instance, targeted drug delivery. Interestingly, magnetic nanochains do occur in nature, and they are thought to be involved in the navigation and geographic orientation of a variety of animals and bacteria, although many open questions on their formation and functioning remain. In this review, we will analyze what is known about the natural formation of magnetic nanochains, as well as the synthetic protocols to produce them in the laboratory, to conclude with an overview of medical applications and an outlook on future opportunities in this exciting research field.
The Effects of pH and Excipients on Exenatide Stability in Solution
Authors: Benet Alexander , Halseth Troy , Kang Jukyung , Kim April , Ackermann Rose , Srinivasan Santhanakrishnan , Schwendeman Steven , Schwendeman Anna
Published: August 2021

Exenatide, a glucagon-like peptide-1 receptor agonist, is the active pharmaceutical ingredient in Byetta® and Bydureon®, two type 2 diabetes drug products that have generics and multiple follow-up formulations currently in development. Even though exenatide is known to be chemically and physically unstable at pH 7.5, there lacks a systematic evaluation of the impact of pH and excipients on the peptide solution stability. In this study, we established analytical methods to measure the chemical and physical degradation of the peptide in solution. Exenatide remained relatively stable at pH 4.5 when incubated at 37 °C. At pH 5.5–6.5, degradation was driven by oxidation, while driven by deamidation at pH 7.5–8.5. Significant aggregation of exenatide at pH 7.5 and 8.5 was detected by size exclusion chromatography and dynamic light scattering. Each pH value greater than 4.5 exhibited unique profiles corresponding to a loss of α-helical content and an increase in unordered structures. The addition of sugars, including mannitol, sorbitol and sucrose, conferred small protective effects against peptide aggregation when incubating at pH 7.5 and 37 °C, as measured by size-exclusion chromatography and dynamic light scattering. The results of this study will be useful for investigators developing generic exenatide products, peptide analogs and novel exenatide drug delivery systems.
Soundpainting Sign Language: Possibilities and Connections with Tactileology
Authors: Millà Arnau
Published: August 2021

This article introduce and expose the language of Soundpainting (SP), its background, and how this artistic tool is being used as a language of communication and creation. It also presents the real-time composition and its peculiarities and the power of collective creation as a creative tool and interaction between artistic disciplines. As there are several cases of sensitive and creative languages, such as Soundpainting, that are used to communicate with artificial intelligence, finally, it expose two of them, which are both still in their embryonic state. Both are collaborations and research between SP sign language and Tactileology. Both can lead to creative results that contribute to new ways of perceiving living art, in a sensitive, social and inclusive way.
Polymer Retention Determination in Porous Media for Polymer Flooding in Unconsolidated Reservoir
Authors: Ilyasov Ilnur , Koltsov Igor , Golub Pavel , Tretyakov Nikolay , Cheban Andrei , Thomas Antoine
Published: August 2021

Polymer flooding is a well-established technique aimed at improved recovery factors from oilfields. Among the important parameters affecting the feasibility of a large deployment, polymer retention is one of the most critical since it directly impacts the oil bank delay and therefore the final economics of the project. This paper describes the work performed for the East-Messoyakhskoe oilfield located in Northern Siberia (Russia). A literature review was first performed to select the most appropriate methodology to assess polymer retention in unconsolidated cores at residual oil saturation. 4 polyacrylamide polymers were selected with molecular weights between 7 and 18 M Da and sulfonated monomer (ATBS) content between 0 and 5% molar. An improved 2-fronts dynamic retention method along with total organic carbon—total nitrogen analyzers were used for concentration measurement. Retention values vary between 93 and 444 The sentence could be rephrased μg/g, with the lowest given by the polymers containing ATBS, corroborating other publications on the topic. This paper also summarizes the main learnings gathered during the adaptation of laboratory procedures and paves the way for a faster and more efficient retention estimation for unconsolidated reservoirs.
Current Status of Cellulosic and Nanocellulosic Materials for Oil Spill Cleanup
Authors: Fürtauer Siegfried , Hassan Mostafa , Elsherbiny Ahmed , Gabal Shaimaa A. , Mehanny Sherif , Abushammala Hatem
Published: August 2021

Recent developments in the application of lignocellulosic materials for oil spill removal are discussed in this review article. The types of lignocellulosic substrate material and their different chemical and physical modification strategies and basic preparation techniques are presented. The morphological features and the related separation mechanisms of the materials are summarized. The material types were classified into 3D-materials such as hydrophobic and oleophobic sponges and aerogels, or 2D-materials such as membranes, fabrics, films, and meshes. It was found that, particularly for 3D-materials, there is a clear correlation between the material properties, mainly porosity and density, and their absorption performance. Furthermore, it was shown that nanocellulosic precursors are not exclusively suitable to achieve competitive porosity and therefore absorption performance, but also bulk cellulose materials. This finding could lead to developments in cost- and energy-efficient production processes of future lignocellulosic oil spillage removal materials.
SEM/EDS Evaluation of the Mineral Deposition on a Polymeric Composite Resin of a Toothpaste Containing Biomimetic Zn-Carbonate Hydroxyapatite (microRepair®) in Oral Environment: A Randomized Clinical Trial
Authors: Butera Andrea , Pascadopoli Maurizio , Gallo Simone , Lelli Marco , Tarterini Fabrizio , Giglia Federico , Scribante Andrea
Published: August 2021

Toothpastes containing biomimetic hydroxyapatite have been investigated in recent years; the behavior of this material in the oral environment has been evaluated directly on dental enamel showing a marked remineralizing activity. To propose microRepair®-based toothpastes (Zn-carbonate hydroxyapatite) for the domiciliary oral hygiene in patients with dental composite restorations, the aim of this study was to evaluate the deposition of Zn-carbonate hydroxyapatite on a polymeric composite resin with Scanning Electron Microscopy/Energy-Dispersive X-ray Spectrometry (SEM/EDS) analysis. Twenty healthy volunteers underwent the bonding of 3 orthodontic buttons on the vestibular surfaces of upper right premolars and first molar. On the surface of the buttons, a ball-shaped mass of composite resin was applied and light-cured. Then, the volunteers were randomly divided into two groups according to the toothpaste used for domiciliary oral hygiene: the Control toothpaste containing stannous fluoride and the Trial toothpaste containing microRepair®. The buttons were debonded after 7 days (T1—first premolar), after 15 days (T2—second premolar), and after 30 days (T3—first molar) to undergo the SEM/EDS analysis. The deposition of calcium, phosphorus, and silicon was assessed through EDS analysis and data were submitted to statistical analysis (p < 0.05). SEM morphologic evaluation showed a marked deposition of the two toothpastes on the surfaces of the buttons. EDS quantitative analysis showed an increase of calcium, phosphorus, and silicon in both the groups, with a statistically significant difference of calcium deposition at T3 for the Trial group. Therefore, the use of toothpaste containing Zn-carbonate hydroxyapatite could be proposed as a device for domiciliary oral hygiene because the deposition of hydroxyapatite on polymeric composite resin could prevent secondary caries on the margins of restorations.
Monomer Conversion, Dimensional Stability, Biaxial Flexural Strength, Ion Release, and Cytotoxicity of Resin-Modified Glass Ionomer Cements Containing Methacrylate-Functionalized Polyacids and Spherical Pre-Reacted Glass Fillers
Authors: Potiprapanpong Wisitsin , Thepveera Whithipa , Khamsuk Chutikarn , Channasanon Somruethai , Tanodekaew Siriporn , Patntirapong Somying , Monmaturapoj Naruporn , Panpisut Piyaphong
Published: August 2021

The aim of this study was to prepare RMGICs for pulp protection that contain polyacids functionalized with methacrylate groups (CMs) to enable light-activated polymerization without the need for toxic 2-hydroxyethyl methacrylate (HEMA) monomers. The effects of using CM liquids with 0 or 5 wt% HEMA on the physical/mechanical properties and cytotoxicity of the experimental RMGICs were assessed. Spherical pre-reacted glass fillers (SPG) were used as the powder phase. The experimental RMGICs were prepared by mixing SPG with CM liquid (0 wt% HEMA, F1) or CMH liquid (5 wt% HEMA, F2). Commercial materials (Vitrebond, VB; TheraCal LC, TC) were used for the comparisons. The degree of monomer conversion and fluoride release of both F1 and F2 were significantly lower than those of VB. F1 showed comparable biaxial flexural strength with VB but higher strength than TC. The dimensional stability (mass/volume changes) of the experimental materials was comparable with that of the commercial materials. F1 and F2 exhibited higher Sr/Ca ion release and relative cell viability than VB. The use of CMH liquid reduced the strength but enhanced the fluoride release of the experimental RMGICs. In conclusion, the experimental RMGICs showed comparable strength but lower cytotoxicity compared to the commercial RMGICs. These novel materials could be used as alternative materials for pulp protection.
Sustainable Development of Hot-Pressed All-Lignocellulose Composites—Comparing Wood Fibers and Nanofibers
Authors: Oliaei Erfan , Lindström Tom , Berglund Lars A.
Published: August 2021

Low-porosity materials based on hot-pressed wood fibers or nanocellulose fibrils (no polymer matrix) represent a new concept for eco-friendly materials with interesting mechanical properties. For the replacement of fossil-based materials, physical properties of wood fiber materials need to be improved. In addition, the carbon footprint and cumulative energy required to produce the material also needs to be reduced compared with fossil-based composites, e.g., glass fiber composites. Lignin-containing fibers and nanofibers are of high yield and special interest for development of more sustainable materials technologies. The present mini-review provides a short analysis of the potential. Different extraction routes of lignin-containing wood fibers are discussed, different processing methods, and the properties of resulting fiber materials. Comparisons are made with analogous lignin-containing nanofiber materials, where mechanical properties and eco-indicators are emphasized. Higher lignin content may promote eco-friendly attributes and improve interfiber or interfibril bonding in fiber materials, for improved mechanical performance.
Structure and Dynamics of Highly Attractive Polymer Nanocomposites in the Semi-Dilute Regime: The Role of Interfacial Domains and Bridging Chains
Authors: Skountzos Emmanuel N. , Karadima Katerina S. , Mavrantzas Vlasis G.
Published: August 2021

Detailed molecular dynamics (MD) simulations are employed to study how the presence of adsorbed domains and nanoparticle bridging chains affect the structural, conformational, thermodynamic, and dynamic properties of attractive polymer nanocomposite melts in the semi-dilute regime. As a model system we have chosen an unentangled poly(ethylene glycol) (PEG) matrix containing amorphous spherical silica nanoparticles with different diameters and at different concentrations. Emphasis is placed on properties such as the polymer mass density profile around nanoparticles, the compressibility of the system, the mean squared end-to-end distance of PEG chains, their orientational and diffusive dynamics, the single chain form factor, and the scattering functions. Our analysis reveals a significant impact of the adsorbed, interfacial polymer on the microscopic dynamic and conformational properties of the nanocomposite, especially under conditions favoring higher surface-to-volume ratios (e.g., for small nanoparticle sizes at fixed nanoparticle loading, or for higher silica concentrations). Simultaneously, adsorbed polymer chains adopt graft-like conformations, a feature that allows them to considerably extend away from the nanoparticle surface to form bridges with other nanoparticles. These bridges drive the formation of a nanoparticle network whose strength (number of tie chains per nanoparticle) increases substantially with increasing concentration of the polymer matrix in nanoparticles, or with decreasing nanoparticle size at fixed nanoparticle concentration. The presence of hydroxyl groups at the ends of PEG chains plays a key role in the formation of the network. If hydroxyl groups are substituted by methoxy ones, the simulations reveal that the number of bridging chains per nanoparticle decreases dramatically, thus the network formed is less dense and less strong mechanically, and has a smaller impact on the properties of the nanocomposite. Our simulations predict further that the isothermal compressibility and thermal expansion coefficient of PEG-silica nanocomposites are significantly lower than those of pure PEG, with their values decreasing practically linear with increasing concentration of the nanocomposite in nanoparticles.
Strain Rate Sensitivity of Polycarbonate and Thermoplastic Polyurethane for Various 3D Printing Temperatures and Layer Heights
Authors: Vidakis Nectarios , Petousis Markos , Korlos Apostolos , Velidakis Emmanouil , Mountakis Nikolaos , Charou Chrisa , Myftari Adrian
Published: August 2021

In this work, strain rate sensitivity was studied for 3D-printed polycarbonate (PC) and thermoplastic polyurethane (TPU) materials. Specimens were fabricated through fused filament fabrication (FFF) additive manufacturing (AM) technology and were tested at various strain rates. The effects of two FFF process parameters, i.e., nozzle temperature and layer thickness, were also investigated. A wide analysis for the tensile strength (MPa), the tensile modulus of elasticity (MPa), the toughness (MJ/m3) and the strain rate sensitivity index ‘m’ was conducted. Additionally, a morphological analysis was conducted using scanning electron microscopy (SEM) on the side and the fracture area of the specimens. Results from the different strain rates for each material were analyzed, in conjunction with the two FFF parameters tested, to determine their effect on the mechanical response of the two materials. PC and TPU materials exhibited similarities regarding their temperature response at different strain rates, while differences in layer height emerged regarding the appropriate choice for the FFF process. Overall, strain rate had a significant effect on the mechanical response of both materials.
Fractional Modeling and Characteristic Analysis of Hydro-Pneumatic Suspension for Construction Vehicles
Authors: Sun Huilai , Li Ruichuan , Xu Jikang , Xu Funing , Zhang Bo , Dong Xinyuan
Published: August 2021

The motion differential equation of hydro-pneumatic suspension is established to describe the vibration characteristics for a certain type of construction vehicle. The output force was deduced from the suspension parameters. Based on the suspension characteristics of a multi-phase medium, fractional calculus theory was introduced, and its fractional Bagley–Torvik equation was formed. The numerical computation by a low-pass filter of the Oustaloup algorithm was performed. The numerical solution of a nonlinear fractional equation was obtained to investigate the vibration characteristics of the suspension fractional system. Through the building of an equal-ratio test platform and simulation model, the fractional- integer-order model simulation and experimental data were compared. When the fractional order is 0.9, it better describes the motion characteristics of suspension system. The experiments show that the experimental data can fit the fractional-order system model well, and thereby prove the model on a hydro-pneumatic suspension system.
Optimum Design of N Continuous Stirred-Tank Bioreactors in Series for Fermentation Processes Based on Simultaneous Substrate and Product Inhibition
Authors: Abu Reesh Ibrahim M.
Published: August 2021

Optimization of the continuous fermentation process is important for increasing efficiency and decreasing cost, especially for complicated biochemical processes described by substrate and product inhibition. The optimum design (minimum volume) of CSTRs in series assuming substrate and product inhibition was determined in this study. The effect of operating parameters on the optimum design was investigated. The optimum substrate concentration in the feed to the first reactor was determined for N reactors in series. The nonlinear, constrained optimization problem was solved using the MATLAB function “fmincon”. It was found that the optimum design is more beneficial at high substrate conversion and at a medium level of feed substrate concentration. The best number of reactors is two to three for optimum arrangements and two for equal-size arrangements. The presence of biomass in the feed to the first reactor reduces the reactor volume, while the presence of product in the feed slightly increases the required total volume. The percentage reduction in the total volume using the optimum design compared to equal-volume design (R%) was determined as a function of substrate conversion and substrate concentration in the feed to the first reactor. The obtained R% values agree with experimental data available in the literature for ethanol fermentation.
From Supporting Moral Competence to Fostering Spiritual Growth: The Psycho-Didactic Potential of the Konstanz Method of Dilemma Discussion (KMDD®)
Authors: Steć Małgorzata , Kulik Małgorzata Maria , Wendołowska Anna
Published: August 2021

This paper aimed to introduce the Konstanz Method of Dilemma Discussion KMDD® as one of the most effective methods that are designed to foster moral competence and, therefore, to promote tolerance and equality, regardless of cultural background, religion, or views. It is mainly used within the educational context, but it can be also implemented in different environments and conditions. The Konstanz Method of Dilemma Discussion should also be considered as the representative of a psycho-didactic approach to education. There is a possibility of assessing KMDD®’s effectiveness with the Moral Competence Test (MCT®), as well as comparing its significance with other methods that are not only based on the discussions of moral and spiritual dilemmas. Therefore, dilemma discussions would seem to be the best framework for practicing not only social skills and a democratic attitude but also positive mental health and psychological stability by providing a background for personal moral and spiritual growth.
Organ Donation in Islam: A Search for a Broader Quranic Perspective
Authors: Islam Tazul
Published: August 2021

Organ donation is a widely debated issue in Islamic scholarship. Muslim jurists, however, have produced a substantial amount of evidence supporting its legality. Despite this, previous research has revealed that Muslim communities around the world are still wary of organ donation. The main reasons for this attitude are motivational and educational in nature. To address these two problems, the purpose of this research is to look into the Quranic conceptual background, which could help to expand the justification of organ donation in the motivational context. This study investigated the Quranic verses that scholars have cited in their writings on organ donation and transplantation. The theoretical underpinnings for the use of those verses were deduced. Data were collected from 36 studies on organ donation that refer to Quranic verses and examined how those verses were analyzed. This study discovered that a number of Quranic verses were primarily used to justify the permissibility of organ donation, with little effort made to analyze the verses using specific methodologies dedicated to the Quranic texts. As a result, the outcome may not be helpful to solve the current dilemma which is Muslim communities’ reluctance to donate organs. Hence, it is important to explore a broad theoretical framework for organ donation based on the Quran. This study suggests how to bring this new perspective to the subject and overcome the existing problem.
Validation of FY-3D MERSI-2 Precipitable Water Vapor (PWV) Datasets Using Ground-Based PWV Data from AERONET
Authors: Xie Yanqing , Li Zhengqiang , Hou Weizhen , Guang Jie , Ma Yan , Wang Yuyang , Wang Siheng , Yang Dong
Published: August 2021

The medium resolution spectral imager-2 (MERSI-2) is one of the most important sensors onboard China’s latest polar-orbiting meteorological satellite, Fengyun-3D (FY-3D). The National Satellite Meteorological Center of China Meteorological Administration has developed four precipitable water vapor (PWV) datasets using five near-infrared bands of MERSI-2, including the P905 dataset, P936 dataset, P940 dataset and the fusion dataset of the above three datasets. For the convenience of users, we comprehensively evaluate the quality of these PWV datasets with the ground-based PWV data derived from Aerosol Robotic Network. The validation results show that the P905, P936 and fused PWV datasets have relatively large systematic errors (−0.10, −0.11 and −0.07 g/cm2), whereas the systematic error of the P940 dataset (−0.02 g/cm2) is very small. According to the overall accuracy of these four PWV datasets by our assessments, they can be ranked in descending order as P940 dataset, fused dataset, P936 dataset and P905 dataset. The root mean square error (RMSE), relative error (RE) and percentage of retrieval results with error within ±(0.05+0.10∗PWVAERONET) (PER10) of the P940 PWV dataset are 0.24 g/cm2, 0.10 and 76.36%, respectively. The RMSE, RE and PER10 of the P905 PWV dataset are 0.38 g/cm2, 0.15 and 57.72%, respectively. In order to obtain a clearer understanding of the accuracy of these four MERSI-2 PWV datasets, we compare the accuracy of these four MERSI-2 PWV datasets with that of the widely used MODIS PWV dataset and AIRS PWV dataset. The results of the comparison show that the accuracy of the MODIS PWV dataset is not as good as that of all four MERSI-2 PWV datasets, due to the serious overestimation of the MODIS PWV dataset (0.40 g/cm2), and the accuracy of the AIRS PWV dataset is worse than that of the P940 and fused MERSI-2 PWV datasets. In addition, we analyze the error distribution of the four PWV datasets in different locations, seasons and water vapor content. Finally, the reason why the fused PWV dataset is not the one with the highest accuracy among the four PWV datasets is discussed.
Assessing Self-Reported Risky Riding Behavior of Motorcyclists at Unsignalized Intersections for Sustainable Transportation
Authors: Leong Lee Vien , Mohd Shafie Shafida Azwina , Gooi Peng Kheng , Goh Wins Cott
Published: August 2021

In Malaysia, as more than 50% of road collisions involve motorcyclists, the traffic safety of motorcyclists is critical and must be given priority. This study aims to understand the effects of attitudes, social influences, and control factors on the risky riding behavior of motorcyclists at unsignalized intersections in Malaysia. A motorcyclist-riding-behavior survey was conducted to collect and analyze the self-reported risky riding behaviors of motorcyclists. Three main analyses, namely, frequency and percentage, crosstabulation and test of independence (chi-squared), and logistic regression were adopted to assess the self-reported risky riding behavior and its correlation with outcomes, social influences, and factors. The obtained results show that negative outcomes (χ2 = 89.689, df = 54, p = 0.002) and negative social influences (χ2 = 32.554, df = 18, p = 0.019) are significantly associated with risky riding behavior, while control factors, inhibiting (χ2 = 66.889, df = 48, p = 0.037) and facilitating factors (χ2 = 96.705, df = 72, p = 0.028), have significant effects on risky riding behavior. A greater comprehension of motorcyclists’ risky riding behavior based on their self-reported risky riding behavior and beliefs can influence motorcyclists in making positive changes in their riding style.
Indigenous Knowledge Systems in Ecological Pest Control and Post-Harvest Rice Conservation Techniques: Sustainability Lessons from Baduy Communities
Authors: Habiyaremye Alexis , Korina Leeja
Published: August 2021

With the impending threat of global climate change, the past decades have witnessed an increasing recognition of the potential contribution of indigenous knowledge to tackling global challenges of environmental sustainability. In this study, we used a qualitative analysis of data collected in September 2018 from key informant interviews and focus group discussion sessions in the Baduy communities in western Java to examine how their swidden cultivation, pest control and rice preservation techniques contribute to strengthening the sustainability of their livelihoods. The study also examines the potential for knowledge sharing between Baduy indigenous knowledge holders and outside scientific communities for mutual enhancement. Our analysis of collected data indicates that while the Baduy are open to sharing their ecological knowledge with outsiders for the sake of a greater environment protection, they remain wary of adopting external knowledge sources, as these external influences constitute a threat of disruption to their own epistemic system and way of life.
Relationship between Starting Torque and Thermal Behaviour for a Permanent Magnet Synchronous Generator (PMSG) Applied with Vertical Axis Wind Turbine (VAWT)
Authors: Trongtorkarn Mintra , Theppaya Thanansak , Techato Kuaanan , Luengchavanon Montri , Kasagepongsarn Chainuson
Published: August 2021

The application of wind turbine technology in low wind speed regions such as Southeast Asia has recently attracted increased attention. Wind turbines are designed as special structures with low starting torque, and many starting torque minimization processes exist for permanent magnet synchronous generators (PMSGs). Plurality is applied to decrease the starting torque in radial flux permanent magnet disk generators. The most popular starting torque minimization method uses a magnet skew technique. When used at 20°, this technique reduced starting torque by 4.72% (on load) under 500 rpm at 50 Hz for 120 min. By contrast, a PMSG with magnet skew conditions set at under 2° reduced electrical power by 3.86%. For high-speed PMSGs, magnet skew techniques affect the generation of heat in the coils (stator), with heat decrease at the middle of the coil, on its surface and between the coils at 2.90%, 3.10% and 2.40%, respectively. PMSGs were installed in vertical axis wind turbines (VAWTs), and heat generation in relation to wind speed and electrical power was assessed. Magnet skew techniques can be used in PMSGs to reduce staring torque, while skew techniques also reduce electrical power and heat generated at the stator.
Innovation and Entrepreneurship for Well-Being and Sustainability
Authors: Meglio Olimpia , Di Paola Nadia
Published: August 2021

Entrepreneurship, innovation, well-being, and sustainability represent the four pillars inspiring our call for papers and driving this Special Issue (hereafter SI) [...]
Trade-Offs and Synergies of Ecosystem Services in the Pearl River Delta Urban Agglomeration
Authors: Zhang Qiongrui , Sun Xuechao , Zhang Kebin , Liao Zhenni , Xu Songjun
Published: August 2021

Since ecosystem services (ESs) have become effective tools for urban planning, spatiotemporal analysis of regional ESs and a deep understanding of the trade-offs among ESs are of great significance to regional governance. In this study, the spatial and temporal changes of four basic ESs were analyzed by combining statistical data with the InVEST model across the Pearl River Delta (PRD) urban agglomeration, China. The trade-offs among the related ESs were analyzed at the urban agglomeration scale and the city scale by correlation analysis. The results showed that: (1) Construction land increased by 6.78% from 2000 to 2018, while cultivated land and forest decreased. (2) Water yield showed an increasing trend, while carbon storage, food production, and habitat quality showed a downward trend from 2000 to 2018. (3) The four ecosystem services were significantly correlated, with synergies existing between water yield and food production, and between habitat quality and carbon storage, while other relationships are trade-offs. What is more, the scale has little influence on the direction of ES trade-off or synergy but influences the degree of the relationship. This empirical evidence on ES relationships in urban agglomerations can provide a reference for the sustainable development of ESs and efficient management of urban agglomerations.