bluuebunny/crossref_metadata_2025 huggingface dataset:
Polypropylene Degradation on Co-Rotating Twin-Screw Extruders
Authors: Altepeter Matthias , Schöppner Volker , Wanke Sven , Austermeier Laura , Meinheit Philipp , Schmidt Leon
Published: May 2023

Nowadays, usable plastic materials with defined properties are created by blending additives into the base polymer. This is the main task of compounding on co-rotating twin-screw extruders. The thermal and mechanical stress occurring in the process leads to a mostly irreversible damage to the material. Consequently, the properties of the polymer melt and the subsequent product are affected. The material degradation of polypropylene (PP) on a 28 mm twin-screw extruder has already been studied and modeled at Kunststofftechnik Paderborn. In this work, the transferability of the previous results to other machine sizes and polypropylene compounds were investigated experimentally. Therefore, pure polypropylene was processed with screw diameters of 25 mm and 45 mm. Furthermore, polypropylene compounds with titanium dioxide as well as carbon fibers were considered on a 28 mm extruder. In the course of the evaluation of the pure polypropylene, the melt flow rates of the samples were measured and the molar masses were calculated on this basis. The compounds were analyzed by gel permeation chromatography. As in the previous investigations, high rotational speeds, low throughputs and high melt temperatures lead to a higher material degradation. In addition, it is illustrated that the previously developed model for the calculation of material degradation is generally able to predict the degradation even for different machine sizes by adjusting the process coefficients. In summary, this article shows that compounders can use the recommendations for action and the calculation model for the material degradation of polypropylene, irrespective of the machine size, to design processes that are gentle on the material.
Polyhydroxyalkanoates (PHAs) from Endophytic Bacterial Strains as Potential Biocontrol Agents against Postharvest Diseases of Apples
Authors: Ignatova Lyudmila , Brazhnikova Yelena , Omirbekova Anel , Usmanova Aizhamal
Published: May 2023

Due to the increasing use and accumulation of petrochemical plastics in the environment and the rapid depletion of natural resources, microbial polyhydroxyalkanoates have great potential to replace them. This study provides new insights in the field of obtaining of polyhydroxyalkanoates (PHAs) from endophytic bacterial strains and applying them as potential biocontrol agents against postharvest diseases of apples. Two strains—Pseudomonas flavescens D5 and Bacillus aerophilus A2—accumulated PHAs in amounts ranging from 2.77 to 5.9 g L−1. The potential to use low-cost substrates such as beet molasses and soapstock for PHA accumulation was shown. The PHAs produced by the Ps. flavescens D5 strain had pronounced antagonistic activity against Penicillium expansum (antifungal property = 62.98–73.08%). The use of PHAs as biocontrol agents significantly reduced the severity of apple blue mold, especially in the preventive treatment option.
Microplastic Index—How to Predict Microplastics Formation?
Authors: Boersma Arjen , Grigoriadi Kalouda , Nooijens Merel G. A. , Henke Sieger , Kooter Ingeborg M. , Parker Luke A. , Dortmans Ardi , Urbanus Jan Harm
Published: May 2023

The presence of microplastics in environmental compartments is generally recognized as a (potential) health risk. Many papers have been published on the abundance of microplastics at various locations around the globe, but only limited knowledge is available on possible mitigation routes. One of the mitigation routes is based on the choice of plastic materials used for products that may unintentionally end up in the environment. As a first approach, this paper presents a method to calculate the tendency of polymers to form microplastics, based on their mechanical and physical properties. A MicroPlastic Index (MPI) that correlates the microplastic formation to polymer properties is defined for both impact and wear of polymers via a theoretical particle size and the energy required to form these particles. A first comparison between calculated and experimental particle size is included. The MPI for impact and wear follow the same trend. Finally, these MPIs are correlated to the respective abundance of the microplastics in the environment, corrected for global production of the corresponding polymers: the higher the MPI, the more microplastics are found in the environment. Thus, the MPI can be used as a basis for choice or redesign of polymers to reduce microplastic formation.
Determination of Mechanical Properties of Sand-Coated Carbon Fiber Reinforced Polymer (CFRP) Rebar
Authors: Yun Hyun-Do , Kim Sun-Hee , Choi Wonchang
Published: May 2023

This experimental study investigates the fundamental mechanical characteristics of the carbon fiber-reinforced polymer (CFRP) bars, including the tensile strength, compressive strength, shear strength, and modulus of elasticity of the CFRP bar. The properties need to be accurately determined to understand the behavior of the concrete structures reinforced with CFRP rebars. The CFRP rebar was coated with sand to enhance the adhesive strength of the concrete. Three diameters of CFRP rebar (D10, D12, and D16) were considered in accordance with ASTM provisions. A coefficient, i.e., the ratio of shear strength to tensile strength, was employed to predict the tensile strength of the CFRP rebar specimens. The test results confirm that the tensile strength of CFRP rebar is dependent on its diameter due to the shear lag effect. A coefficient in the range of 0.17 to 0.2 can be used to predict the tensile strength of CFRP rebar using shear strength.
Curing of Poly(styrene-co-methyl methacrylate-co-2-hydroxyethyl methacrylate) Terpolymers in the Presence of Amino Compounds of Different Structures
Authors: Pugacheva Tatyana A. , Kurbatov Vladimir G. , Vaganov Evgeniy V. , Malkov Georgiy V. , Tarusina Ksenya A. , Organ Vlada M. , Mitrofanova Elena V. , Tarasov Alexander E. , Badamshina Elmira R.
Published: May 2023

The process of curing the acrylic oligomers for rapid thermal curing coatings in the presence of hexa(methoxymethyl)melamine (HMMM), tetra(butoxymethyl)glycoluril (TBMG), and tetra(methoxymethyl)glycoluril (TMMG) has been studied. When HMMM is used as a hardener, the content of hydroxyl groups in the terpolymer and also the crosslinking agent concentration have little effect on the initial cure rate. It has been established that during the curing of the TMMG composition, the amount of the network polymer and the initial curing rate decrease at short curing times only. It has also been revealed that the use of butoxy groups instead of methoxy groups as blocking agents leads both to a decrease in the initial cure rate and the gel fraction limiting value from 98 to 80%. When it comes to TBMG-containing compositions, a decrease in the part of hydroxyl groups in the copolymer leads to a significant fall in the initial curing rate and also in the gel fraction content. Regardless of the crosslinking agent used, an acceleration of the curing process is observed with an increase in the catalyst content in the compositions.
Chitosan Polymer Functionalized-Activated Carbon/Montmorillonite Composite for the Potential Removal of Lead Ions from Wastewater
Authors: Alsohaimi Ibrahim Hotan , Alhumaimess Mosaed S. , Hassan Hassan M. A. , Reda Mohamed , Aldawsari Abdullah M. , Chen Qiao , Kariri Mohammed Abdo
Published: May 2023

A simple approach for synthesizing a highly adsorbent composite was described for the uptake of heavy metal ions from wastewater. A simple approach for synthesizing a highly adsorbent composite was also described for the elimination of heavy metal ions from contaminated water. The nanocomposite was synthesized via a polymer grafting of chitosan on the activated carbon surface, followed by a stacking process with the layers of montmorillonite clay. The spectroscopic analyses were exploited to confirm the composite structure of the prepared materials. Various adsorption parameters, such as pH, initial concentration, and adsorption time, were assessed. The results showed that the adsorption capacity of the composite for Pb2+ ions increased as the pH increased until it reached pH 5.5. The maximum adsorption capacity was observed at an initial Pb2+ level of 20 mg/L and a contact time of 150 min. Kinetic models were evaluated, and the pseudo second-order model showed the best match. The adsorption isotherm data were processed by fitting the model with different isotherm behaviors, and the Langmuir isotherm was found to be the most suitable for the system. The maximum adsorption capacity for Pb2+ ion on the MMT/CS/AC composite was found to be 50 mg/g at pH 5.5. Furthermore, the composite maintained a high adsorption capability of 85% for five adsorption–desorption cycles. Overall, this composite is envisioned as an addition to the market of wastewater remediation technology due to its chemical structure, which provides influential functional groups for wastewater treatment.
Nanocarbon Black and Molybdenum Disulfide Hybrid Filler System for the Enhancement of Fracture Toughness and Electromechanical Sensing Properties in the Silicone Rubber-Based Energy Harvester
Authors: Alam Md Najib , Kumar Vineet , Jeong Taemin , Park Sang-Shin
Published: May 2023

Recently, hybrid fillers have been found to be more advantageous in energy-harvesting composites. This study investigated the mechanical and electromechanical performances of silicone rubber-based composites made from hybrid fillers containing conductive nanocarbon black (NCB) and molybdenum disulfide (MoS2). A hybrid filler system containing only 3 phr (per hundred grams of rubber) MoS2 and 17 phr NCB provided higher fracture strain, better tensile strength, and excellent toughness values compared to the 20 phr NCB-only-filled and 5 phr MoS2-only-filled rubber composites. The chemical cross-link densities suggest that NCB promoted the formation of cross-links, whereas MoS2 slightly reduced the cross-link density. The higher mechanical properties in the hybrid filler systems suggest that the filler particles were more uniformly distributed, which was confirmed by the scanning electron microscope study. Uniformly distributed filler particles with moderate cross-link density in hybrid filler systems greatly improved the fracture strain and fracture toughness. For example, the hybrid filler with a 17:3 ratio of NCB to MoS2 showed a 184% increment in fracture toughness, and a 93% increment in fracture strain, compared to the 20 phr NCB-only-filled composite. Regarding electromechanical sensing with 2 kPa of applied cyclic pressure, the hybrid filler (17:3 CB to MoS2) performed significantly better (~100%) than the 20 phr NCB-only compound. This may have been due to the excellent distribution of conducting NCB networks and piezoelectric MoS2 that caused symmetric charging–discharging in the toughened hybrid composite. Thus, hybrid composites with excellent fatigue resistance can find dynamic applications, such as in blood pressure measurement.
The Contribution of BaTiO3 to the Stability Improvement of Ethylene–Propylene–Diene Rubber: Part I—Pristine Filler
Authors: Borbath Tunde , Nicula Nicoleta , Zaharescu Traian , Borbath Istvan , Boros Tiberiu Francisc
Published: May 2023

This study presents the functional effects of BaTiO3 powder loaded in ethylene–propylene–diene rubber (EPDM) in three concentrations: 0, 1, and 2.5 phr. The characterization of mechanical properties, oxidation strength, and biological vulnerability is achieved on these materials subjected to an accelerated degradation stimulated by their γ-irradiation at 50 and 100 kGy. The thermal performances of these materials are improved when the content of filler becomes higher. The results obtained by chemiluminescence, FTIR-ATR, and mechanical testing indicate that the loading of 2.5 phr is the most proper composition that resists for a long time after it is γ-irradiated at a high dose. If the oxidation starts at 176 °C in the pristine polymer, it becomes significant at 188 and 210 °C in the case of composites containing 1 and 2.5 phr of filler, respectively. The radiation treatment induces a significant stability improvement measured by the enlargement of temperature range by more than 1.5 times, which explains the durability growth for the radiation-processed studied composites. The extension of the stability period is also based on the interaction between degrading polymer substrate and particle surface in the composite richest in titanate fraction when the exposure is 100 kGy was analyzed. The mechanical testing as well as the FTIR investigation clearly delimits the positive effects of carbon black on the functionality of EPDM/BaTiO3 composites. The contribution of carbon black is a defining feature of the studied composites based on the nucleation of the host matrix by which the polymer properties are effectively ameliorated.
1,3-Pentadiene-Assistant Living Anionic Terpolymerization: Composition Impact on Kinetics and Microstructure Sequence Primary Analysis
Authors: Xiong Qiaoqiao , Fu Yawen , Xu Jundong , Gu Zhuowei , Peng Chengjun , Tan Haoyun , Dai Qiqi , Cao Yujie , Xie Fengli , Li An , Yi Wenjun , Li Lijun , Liu Kun
Published: May 2023

The combination of a living anionic technology and a unique alternating strategy provided an exciting opportunity to prepare novel and well-defined poly(1,3-pentadiene-co-syrene-co-1,1-diphenylethylene) resins consisting of three alternating sequences of modules (A/B/C zwitterions). “A” being Styrene (St)/1,3-pentadiene (PD), “B” being diphenylethylene (DPE)/PD, “A” being DPE/St, respectively, A wide composition range of new polyolefin resins, i.e., poly (A-co-B), poly (A-co-C), and poly (B-co-C), with controlled molecular weight and very narrow molecular weight and composition distributions have been prepared by a one-pot living characteristic method. In the section of kinetic analysis, the terpolymer yields and kinetic parameters were strongly dependent on the feed/comonomer ratio as well as the content of the alternating structure. The competition copolymerization behaviors of A/B, B/C, and A/C were studied in detail in this work. By contrast, the microstructure and the thermal property of the resulting terpolymer were investigated via Nuclear magnetic resonance (NMR) and Differential scanning calorimetry (DSC) analysis. The results of 1H NMR tracking the change of [Aromatic ring]/[C=C] value indicated the distinctive copolymer-ization behavior of the selective “alternating-modules”. The glass transition temperature (Tg) was very sensitive to the terpolymer composition. By contrast to poly(A-ran-B) with only one obvious Tg, there were two Tgs in the A/C and B/C copolymerization cases. Moreover, the desirable high Tg ~ 140 °C resin was limited to the terpolymers with up to 50 mol % DPE. Finally, the “ABC-X” mechanism was proposed to interpret the unique terpolymerization behavior, which belongs to the classical “bond-forming initiation” theory.
Adsorption of Copper and Arsenic from Water Using a Semi-Interpenetrating Polymer Network Based on Alginate and Chitosan
Authors: ALSamman Mohammad T. , Sánchez Julio
Published: May 2023

New biobased hydrogels were prepared via a semi-interpenetrating polymer network (semi-IPN) using polyacrylamide/chitosan (PAAM/chitosan) hydrogel for the adsorption of As(V) or poly acrylic acid/alginate (PAA/alginate) hydrogel for the adsorption of Cu(II). Both systems were crosslinked using N,N′-methylenebisacrylamide as the crosslinker and ammonium persulfate as the initiating agent. The hydrogels were characterized by SEM, Z-potential, and FTIR. Their performance was studied under different variables, such as the biopolymer effect, adsorbent dose, pH, contact time, and concentration of metal ions. The characterization of hydrogels revealed the morphology of the material, with and without biopolymers. In both cases, the added biopolymer provided porosity and cavities’ formation, which improved the removal capacity. The Z-potential informed the surface charge of hydrogels, and the addition of biopolymers modified it, which explains the further metal removal ability. The FTIR spectra showed the functional groups of the hydrogels, confirming its chemical structure. In addition, the adsorption results showed that PAAM/chitosan can efficiently remove arsenic, reaching a capacity of 17.8 mg/g at pH 5.0, and it can also be regenerated by HNO3 for six cycles. On the other hand, copper-ion absorption was studied on PAA/alginate, which can remove with an adsorption capacity of 63.59 mg/g at pH 4.0, and the results indicate that it can also be regenerated by HNO3 for five cycles.
Preparation and Properties of a Novel Cross-Linked Network Waterborne Polyurethane for Wood Lacquer
Authors: Zhou Yuanyuan , Liu Yan , Xin Binjie , Qin Ying , Kuang Guankun
Published: May 2023

Waterborne polyurethane (WPU) is a waterborne coating with excellent physicochemical properties. Its deficiencies of water resistance, chemical resistance, staining, and hardness have limited the wide application of polyurethane in the wood lacquer market. In this study, polycarbonate diols (PCDL) were used as soft segments and WPCU was modified by cross-linking using Trimethylolpropane (TMP) to prepare polycarbonate type WPU (WPCU) with cross-linked network structure. The new wood lacquer was prepared by adding various additives and tested by applying it on wood board. The successful synthesis of WPCU was determined by FTIR testing, and the cross-linking degree of WPCU was probed by low-field NMR. The viscosity of the cross-linked WPCU emulsion showed a decreasing trend compared to the uncross-linked WPCU emulsion, and WPCU-2 had the smallest particle size. Compared with the uncrosslinked WPCU film, the crosslinked WPCU film had lower water absorption (2.2%), higher water contact angle (72.7°), excellent tensile strength (44.02 MPa), higher thermomechanical, and better water and alcohol resistance. The effect of crosslinker content on the microphase separation of WPCU chain segments on the surface roughness of the film was investigated by SEM. The wood paint prepared by WPCU emulsion has good dry heat resistance, chemical resistance, and adhesion, and the hardness of the wood paint when the TMP content is 3% reaches H. It also has good resistance to sticky stains, which can be used to develop new wood lacquer.
Rigid Polyurethane Biofoams Filled with Pine Seed Shell and Yerba Mate Wastes
Authors: Acosta Andrey Pereira , Kairytė Agnė , Członka Sylwia , Miedzińska Karolina , Aramburu Arthur Behenck , Barbosa Kelvin Techera , Amico Sandro Campos , Delucis Rafael de Avila
Published: May 2023

Pine seed shells and yerba mate are common wastes leftover from the food and beverage industry. This study presents the development of rigid polyurethane foams (RPUFs) filled with pine seed shells and yerba mate at 5, 10 and 15 wt%. The fillers were characterized for chemical properties using bench chemistry analyses, and the RPUFs were investigated in terms of chemical, morphological, mechanical, thermal and colorimetric characteristics. The main results indicated that yerba mate showed good compatibility with the polyurethane system, probably because its available hydroxyl groups reacted with isocyanate groups to form urethane bonds, producing increases in mechanical and thermal properties. However, pine seed shell did not appear to be compatible. Anisotropy increased slightly, as there was an increase in the percentage of reinforcement. The mechanical properties of the yerba mate reinforced foams proved stable, while there was a loss of overall up to ~50% for all mechanical properties in those reinforced with pine seed shell. Thermal properties were improved up to ~40% for the yerba mate reinforced foams, while those reinforced with pine nuts were stable. It was possible to observe a decrease in the glass transition temperature (Tg) of ~−5 °C for the yerba mate reinforced foams and ~−14 °C for the pine seed shell reinforced ones.
Assessment of Soy Protein Acid Hydrolysate—Xanthan Gum Mixtures on the Stability, Disperse and Rheological Properties of Oil-in-Water Emulsions
Authors: Ćirin Dejan , Pavlović Nebojša , Nikolić Ivana , Krstonošić Veljko
Published: May 2023

There is a growing need for natural ingredients that could be utilized for the production of food, pharmaceutical, and cosmetic emulsions. Soy protein acid hydrolysate (SPAH) is a plant-based additive used in the food industry mainly as a flavor enhancer. For the purpose of this work, however, it was mixed with a well-known natural polysaccharide, xanthan gum (XG), to produce stable 30% (w/w) sunflower oil-in-water emulsions using a rotor-stator homogenizer. In order to assess the emulsifying properties of the SPAH and its mixtures with XG, the surface tension properties of their water solutions, particle size, creaming stability, and rheological properties of the emulsions were investigated. Since the emulsions prepared using only SPAH, in various concentrations, were not stable, systems containing 5% of SPAH and 0.1, 0.2, 0.3, 0.4, or 0.5% of XG were then studied. The increase in concentration of the macromolecule led to an increase in creaming stability. The emulsions with 5% SPAH and 0.5% XG were stable for at least 14 days. The increase in XG concentration led to a decrease in d4,3, while consistency index and non-Newtonian behavior increased. The systems containing SPAH, in the absence of XG, showed shear-thinning flow behavior, which was changed to thixotropic with the addition of XG. Viscoelastic properties of emulsions containing over 0.2% of XG were confirmed by oscillatory rheological tests, demonstrating the dominance of elastic (G’) over viscous (G”) modulus.
Nanoparticle-Based Drug Delivery Systems: An Inspiring Therapeutic Strategy for Neurodegenerative Diseases
Authors: Duan Linyan , Li Xingfan , Ji Rong , Hao Zhizhong , Kong Mingyue , Wen Xuejun , Guan Fangxia , Ma Shanshan
Published: May 2023

Neurodegenerative diseases are common, incurable neurological disorders with high prevalence, and lead to memory, movement, language, and intelligence impairments, threatening the lives and health of patients worldwide. The blood–brain barrier (BBB), a physiological barrier between the central nervous system and peripheral blood circulation, plays an important role in maintaining the homeostasis of the intracerebral environment by strictly regulating the transport of substances between the blood and brain. Therefore, it is difficult for therapeutic drugs to penetrate the BBB and reach the brain, and this affects their efficacy. Nanoparticles (NPs) can be used as drug transport carriers and are also known as nanoparticle-based drug delivery systems (NDDSs). These systems not only increase the stability of drugs but also facilitate the crossing of drugs through the BBB and improve their efficacy. In this article, we provided an overview of the types and administration routes of NPs, highlighted the preclinical and clinical studies of NDDSs in neurodegenerative diseases, and summarized the combined therapeutic strategies in the management of neurodegenerative diseases. Finally, the prospects and challenges of NDDSs in recent basic and clinical research were also discussed. Above all, NDDSs provide an inspiring therapeutic strategy for the treatment of neurodegenerative diseases.
Biodegradable Green Composites: Effects of Potassium Permanganate (KMnO4) Treatment on Thermal, Mechanical, and Morphological Behavior of Butea Parviflora (BP) Fibers
Authors: Abisha M. , Priya R. Krishna , Arunachalam Krishna Prakash , Avudaiappan Siva , Saavedra Flores Erick I. , Parra Pablo Fernando
Published: May 2023

This study emphasizes the importance of utilizing biodegradable material Butea parviflora (BP) fiber for sustainable solutions. BP fiber offers numerous ecological benefits, such as being lightweight, biodegradable, and affordable to recycle. The study examines the effects of potassium permanganate (KMnO4) treatment on BP fiber and analyzes its physical and chemical behavior using various methods, including X-ray Diffraction (XRD) analysis, tensile testing, thermogravimetric analysis, thermal conductivity, Scanning Electron Microscopy (SEM), and Fourier Transform Infrared spectroscopic (FTIR) analysis. The results demonstrate that BP fiber possesses low density (1.40 g/cc) and high cellulose content (59.4%), which fosters compatibility between the matrix and resin. XRD analysis indicates a high crystallinity index (83.47%) and crystallite size (6.4 nm), showcasing exceptional crystalline behavior. Treated fibers exhibit improved tensile strength (198 MPa) and Young’s modulus (4.40 GPa) compared to untreated fibers (tensile strength—92 MPa, tensile modulus—2.16 GPa). The Tg-DTA thermograms reveal the fiber’s thermal resistance up to 240 °C with a kinetic activation energy between 62.80–63.46 KJ/mol. Additionally, the lowered thermal conductivity (K) from Lee’s disc experiment suggests that BP fiber could be used in insulation applications. SEM photographic results display effective surface roughness for composite making, and FTIR studies reveal vibrational variations of cellulosic functional groups, which correlates with increased cellulosic behavior. Overall, the study affirms the potential of BP fiber as a reinforcing material for composite-making while emphasizing the importance of utilizing biodegradable materials for sustainability.
LDH@Boronate Polymer Core–Shell Nanoparticles: Nanostructure Design for Synergistically Enhancing the Flame Retardancy of Epoxy Resin
Authors: Chi Cheng , He Siyuan , Peng Chaohua , Zeng Birong , Xia Long , Miao Zhongxi , Xu Hui , Wang Shuchuan , Chen Guorong , Dai Lizong
Published: May 2023

As a promising nanofiller, layered double hydroxides (LDHs) can advance the fire safety of epoxy resin (EP), but so far, due to the problems of dispersion and low efficiency, it has still been a challenge to incorporate the flame retardancy and mechanical properties of EP nanocomposites effectively under the circumstance of a low additive amount. In this work, we take LDHs as the template, via the adsorption of a catechol group and the condensation polymerization between catechol groups and phenylboric acid groups, to prepare a core–shell structured nanoparticle LDH@BP, which contains rich flame-retardant elements. EP/LDH@BP nanocomposites were prepared by introducing LDH@BP into EP. The experimental results indicate that, compared with the original LDH, LDH@BP disperses uniformly in the EP matrix, and the flame retardancy and mechanical properties of EP/LDH@BP are significantly improved. At a relatively low content (5 wt%), EP/LDH@BP reached the rating of V-0 in the UL-94 test, LOI was increased to 29.1%, and peak heat release rate (PHRR) was reduced by 35.9% in cone calorimeter tests, which effectively inhibited the release of heat and toxic smoke during the combustion process of EP. Simultaneously, the mechanical properties of EP/LDH@BP have been improved satisfactorily. The above results derive from the reasonable architectural design of organic–inorganic nano-hybrid flame retardants and provide a novel method for the construction of efficient and balanced EP nanocomposite system with LDHs.
Economic Analysis: Green Hydrogen Production Systems
Authors: Muñoz Díaz María Teresa , Chávez Oróstica Héctor , Guajardo Javiera
Published: May 2023

The continued use of energy sources based on fossil fuels has various repercussions for the environment. These repercussions are being minimized through the use of renewable energy supplies and new techniques to decarbonize the global energy matrix. For many years, hydrogen has been one of the most used gases in all kinds of industry, and now it is possible to produce it efficiently, on a large scale, and in a non-polluting way. This gas is mainly used in the chemical industry and in the oil refining industry, but the constant growth of its applications has generated the interest of all the countries of the world. Its use in transportation, petrochemical industries, heating equipment, etc., will result in a decrease in the production of greenhouse gases, which are harmful to the environment. This means hydrogen is widely used and needed by countries, creating great opportunities for hydrogen export business. This paper details concepts about the production of green hydrogen, its associated technologies, and demand projections. In addition, the current situation of several countries regarding the use of this new fuel, their national strategy, and advances in research carried out in different parts of the world for various hydrogen generation projects are discussed. Additionally, the great opportunities that Chile has for this new hydrogen export business, thanks to the renewable energy production capacities in the north and south of the country, are discussed. The latter is key for countries that require large amounts of hydrogen to meet the demand from various industrial, energy, and transportation sectors. Therefore, it is of global importance to determine the real capacities that this country has in the face of this new green fuel. For this, modeling was carried out through mathematical representations, showing the behavior of the technologies involved in the production of hydrogen for a system composed of an on-grid photovoltaic plant, an electrolyser, and compressor, together with a storage system. The program optimized the capacities of the equipment in such a way as to reduce the costs of hydrogen production and thereby demonstrate Chile’s capacity for the production of this fuel. From this, it was found that the LCOH for the case study was equivalent to 3.5 USD/kg, which is not yet considered a profitable value for the long term. Due to this, five case studies were analyzed, to see what factors influence the LCOH, and thereby reduce it as much as possible.
Digital Twin Based Design and Experimental Validation of a Continuous Peptide Polishing Step
Authors: Zobel-Roos Steffen , Vetter Florian , Scheps Daniel , Pfeiffer Marcus , Gunne Matthias , Boscheinen Oliver , Strube Jochen
Published: May 2023

Optimizing or debottlenecking existing production plants is a challenging task. In this case study, an existing reversed phased chromatography polishing step for peptide purification was optimized with the help of a digital twin. The existing batch chromatography was depicted digitally with the general rate model. Model parameter determination and model validation was done with dedicated experiments. The digital twin was then used to identify optimized process variants, especially continuous chromatography steps. MCSGP was found to achieve high purities and yield but at the cost of productivity due to column synchronization. An alternative Continuous Twin Column chromatography process (CTCC) was established that eliminates unnecessary waiting times. Ensuring the same or higher purity compared to the batch process, the continuous process achieved a yield increase of 31% and productivity increase of 27.6%. Experimental long runs confirmed these results.
Effect of the Freezing Step on Primary Drying Experiments and Simulation of Lyophilization Processes
Authors: Juckers Alex , Knerr Petra , Harms Frank , Strube Jochen
Published: May 2023

Lyophilization is a widely used preservation method for thermosensitive products. It consists of three process steps: freezing, primary and secondary drying. One of the major drawbacks is the long processing time. The main optimization effort was put into the primary drying phase since it is usually the longest phase. However, the freezing step is of immense importance for process efficiency and product quality. The lack of control during freezing comprises a challenge for process design and tech transfer. In this study, four different freezing steps (shelf-ramped freezing with and without holding step, precooled shelves and an ice fog method for controlled nucleation) are used and their impact on primary drying experiments and simulations is shown. Only the ice fog method is able to control the nucleation temperature leading to low dry layer resistances with low deviations. During the primary drying simulations, the control of the nucleation temperature drastically increases the precision and accuracy of the product temperature prediction. For optimal primary drying design and model predictive control, the nucleation temperature is strongly recommended to be controlled inside a Process Analytical Technology (PAT) concept to achieve reliable and reproducible process conditions.
Impact of Teaching Workload on Scientific Productivity: Multidimensional Analysis in the Complexity of a Mexican Private University
Authors: Ramirez-Montoya Maria Soledad , Ceballos Hector G. , Martínez-Pérez Sandra , Romero-Rodríguez Luis M.
Published: May 2023

Researchers primarily dedicate their time to teaching in Latin American universities. For this reason, it is essential to determine how teaching time affects (or contributes to) the scientific productivity of researchers working under these conditions. We analyzed the incidence of gender, groups taught at undergraduate and graduate levels, the researcher proficiency level, and the number of thesis students advised, among others, for the impact on the scientific productivity (annual publications) of a group of professors. We analyzed the data using both statistical and regression methods. Contrary to our initial hypothesis, the number of groups taught does not significantly influence research productivity; it is affected by other factors such as belonging to the Mexican Researcher System (SNI) or having a researcher or administrative position at the institution. Our results can help guide the formulation of academic and research policies that contribute to the scientific productivity of Latin American universities.
“Hair for Freedom” Movement in Iran: Interreligious Dialogue in Social Media Activism?
Authors: Navarro Celina , Peres-Neto Luiz
Published: May 2023

After the death of Masha Amini at the hands of the Iranian Morality Police for not wearing the hijab, in accordance with what they considered appropriate in September 2022, a social media campaign called “Hair for Freedom” was sparked on different platforms, with videos of women cutting their hair in protest over Iranian women’s rights and Amini’s death. This paper analyzes whether this digital feminist movement enacted an interreligious dialogue (IRD). Based on content analysis and topic modeling of the publications retrieved from three major platforms, Twitter, Instagram, and TikTok, the results indicate that this was mainly a Western movement focused on women’s bodies as a political symbol in authoritarian Islamic regimes and has not achieved an IRD since most social media posts reproduced the hashtag #HairForFredom without opening a religious discussion. As observed in other digital movements, conclusions indicate that social media activism does not offer an opportunity to engage in dialogues to enlighten the public sphere. On the contrary, the focus appears to provide users with the opportunity to enhance their reputation by engaging in popular social media campaigns that promote social change.
Paddy Rice Phenological Mapping throughout 30-Years Satellite Images in the Honghe Hani Rice Terraces
Authors: Yang Jianbo , Xu Jianchu , Zhou Ying , Zhai Deli , Chen Huafang , Li Qian , Zhao Gaojuan
Published: May 2023

The Honghe Hani Rice Terraces represent the coexistence between natural and cultural systems. Despite being listed as a World Heritage Site in 2013, certain natural and anthropogenic factors have changed land use/land cover, which has led to a reduction in the size of the paddy rice area. It is difficult to accurately assess these changes due to the lack of historical maps of paddy rice croplands with fine spatial resolution. Therefore, we integrated a random forest classifier and phenological information to improve mapping accuracy and stability. We then mapped the historical distribution of land use/land cover in the Honghe Hani Rice Terraces from 1989–1991 to 2019–2021 using the Google Earth Engine. Finally, we analyzed the driving forces of land use types in the Honghe Hani Rice Terraces. We found that: (1) forests, shrubs or grasslands, and other croplands could be discriminated from paddy rice during the flooding and transplanting period, and water bodies and buildings could also be discriminated from paddy rice during the growing and harvesting period. (2) Inputting phenological feature data improved mapping accuracy and stability compared with single phenological periods. (3) In the past thirty years, 10.651%, 8.810%, and 5.711% of paddy rice were respectively converted to forests, shrubs or grasslands, and other croplands in the Honghe Hani Rice Terraces. (4) Lower agricultural profits and drought led to problems in identifying the driving mechanisms behind paddy rice distribution changes. This study demonstrates that phenological information can improve the mapping accuracy of rice terraces. It also provides evidence for the change in the size of the rice terrace area and associated driving forces in Southwest China.
Image Processing Techniques for Concrete Crack Detection: A Scientometrics Literature Review
Authors: Khan Md. Al-Masrur , Kee Seong-Hoon , Pathan Al-Sakib Khan , Nahid Abdullah-Al
Published: May 2023

Cracks in concrete surfaces are one of the most prominent causes of the degradation of concrete structures such as bridges, roads, buildings, etc. Hence, it is very crucial to detect cracks at an early stage to inspect the structural health of the concrete structure. To solve the drawbacks of manual inspection, Image Processing Techniques (IPTs), especially those based on Deep Learning (DL) methods, have been investigated for the past few years. Due to the groundbreaking development of this field, researchers have devoted their endeavors to detecting cracks using DL-based IPTs and as a result, the techniques have given answers to many challenging problems. However, to the best of our knowledge, a state-of-the-art systematic review paper is lacking in this field that would present a scientometric analysis as well as a critical survey of the existing works to document the research trends and summarize the prominent IPTs for detecting cracks in concrete structures. Therefore, this article comes forward to spur researchers with a systematic review of the relevant literature, which will present both scientometric and critical analysis of the papers published in this research area. The scientometric data that are brought out from the articles are analyzed and visualized by using VOSviewer and CiteSpace text mining tools in terms of some parameters. Furthermore, this article elucidates research from all over the world by highlighting and critically analyzing the incarnated essence of some of the most influential papers. Moreover, this research raises some common questions as well as extracts answers from the analyzed papers to highlight various features of the utilized methods.
The Benefits of Continental-Scale High-Resolution Hydrological Modeling in the Detection of Extreme Hydrological Events in China
Authors: Zhu Bowen , Xie Xianhong , Wang Yibing , Zhao Xuehua
Published: May 2023

High-resolution hydrological modeling is crucial for detecting extreme hydrological events and understanding fundamental terrestrial processes. However, spatial resolutions in current hydrological modeling studies have been mostly constrained to relatively coarse resolution (~10–100 km), and they therefore have a difficult time addressing flooding or drought issues with fine resolutions. In this study, a continental-scale high-resolution hydrological modeling framework (0.0625°, ~6 km) driven by remote sensing products was used to detect extreme hydrological event occurrences in China and evaluated based on the Variable Infiltration Capacity (VIC) model. The results showed that the developed model provided more detailed information than the coarser resolution models (a 0.25° and 1°), thereby capturing the timing, duration, and spatial extent of extreme hydrologic events regarding the 2012 Beijing flood and 2009/10 drought in Hai River Basin. Here, the total water storage changes were calculated based on the VIC model (−0.017 mm/year) and Gravity Recovery and Climate Experiment (GRACE) satellite (−0.203 mm/year) to reflect the water availability caused by climate change and anthropogenic factors. This study found that the 0.0625° dataset could capture detailed changes, thereby providing reliable information during occurrences of extreme hydrological events. The high-resolution model integrated with remote sensing products could be used for accurate evaluations of continental-scale extreme hydrological events and can be valuable in understanding its long-term occurrence and water resource security.
The Use of Regional Data Assimilation to Improve Numerical Simulations of Diurnal Characteristics of Precipitation during an Active Madden–Julian Oscillation Event over the Maritime Continent
Authors: Cui Zhiqiang , Pu Zhaoxia
Published: May 2023

This study examines the impact of regional data assimilation on diurnal characteristics of precipitation and winds over the Maritime Continent (MC) using a set of cloud-permitting-scale (~3 km) numerical simulations with the mesoscale community Weather Research and Forecasting (WRF) model and the NCEP Gridpoint Statistical Interpolation (GSI)-based ensemble-3DVAR hybrid data assimilation system. Numerical experiments focus on January 2018, when a well-defined, active Madden–Julian Oscillation (MJO) propagated through the MC region. Available conventional and satellite data are assimilated. Results show that simulated precipitation with data assimilation generally agrees better with satellite-derived rainfall than the control simulation without data assimilation. Simulations with data assimilation also reproduce the diurnal cycle of precipitation better, especially for the timing of the precipitation peak. Data assimilation modulates the overstrong (overweak) diurnal forcing over the land (ocean) in the control simulation. The vertical phase shift of the thermodynamic environment, associated with the timing of vertical motion transition along with low-level water vapor supplies, results in maximum precipitation occurring later, especially over land. To further demonstrate the impact of data assimilation, an additional experiment assimilates NASA Cyclone Global Navigation Satellite System (CYGNSS)-derived ocean surface winds. The results indicate that the assimilation of CYGNSS data exhibits an evident impact on the diurnal variation of surface variables and a similar shift in the diurnal cycle of precipitation. Overall, this study highlights the importance of regional data assimilation in improving the representation of precipitation over the MC, paving the way for a better understanding of the interactions of local diurnal convective precipitation cycles with MJO.
A CNN-Transformer Network Combining CBAM for Change Detection in High-Resolution Remote Sensing Images
Authors: Yin Mengmeng , Chen Zhibo , Zhang Chengjian
Published: May 2023

Current deep learning-based change detection approaches mostly produce convincing results by introducing attention mechanisms to traditional convolutional networks. However, given the limitation of the receptive field, convolution-based methods fall short of fully modelling global context and capturing long-range dependencies, thus insufficient in discriminating pseudo changes. Transformers have an efficient global spatio-temporal modelling capability, which is beneficial for the feature representation of changes of interest. However, the lack of detailed information may cause the transformer to locate the boundaries of changed regions inaccurately. Therefore, in this article, a hybrid CNN-transformer architecture named CTCANet, combining the strengths of convolutional networks, transformer, and attention mechanisms, is proposed for high-resolution bi-temporal remote sensing image change detection. To obtain high-level feature representations that reveal changes of interest, CTCANet utilizes tokenizer to embed the features of each image extracted by convolutional network into a sequence of tokens, and the transformer module to model global spatio-temporal context in token space. The optimal bi-temporal information fusion approach is explored here. Subsequently, the reconstructed features carrying deep abstract information are fed to the cascaded decoder to aggregate with features containing shallow fine-grained information, through skip connections. Such an aggregation empowers our model to maintain the completeness of changes and accurately locate small targets. Moreover, the integration of the convolutional block attention module enables the smoothing of semantic gaps between heterogeneous features and the accentuation of relevant changes in both the channel and spatial domains, resulting in more impressive outcomes. The performance of the proposed CTCANet surpasses that of recent certain state-of-the-art methods, as evidenced by experimental results on two publicly accessible datasets, LEVIR-CD and SYSU-CD.
Toward a Data Fusion Index for the Assessment and Enhancement of 3D Multimodal Reconstruction of Built Cultural Heritage
Authors: Pamart Anthony , Abergel Violette , de Luca Livio , Veron Philippe
Published: May 2023

In the field of digital cultural heritage (DCH), 2D/3D digitization strategies are becoming more and more complex. The emerging trend of multimodal imaging (i.e., data acquisition campaigns aiming to put in cooperation multi-sensor, multi-scale, multi-band and/or multi-epochs concurrently) implies several challenges in term of data provenance, data fusion and data analysis. Making the assumption that the current usability of multi-source 3D models could be more meaningful than millions of aggregated points, this work explores a “reduce to understand” approach to increase the interpretative value of multimodal point clouds. Starting from several years of accumulated digitizations on a single use-case, we define a method based on density estimation to compute a Multimodal Enhancement Fusion Index (MEFI) revealing the intricate modality layers behind the 3D coordinates. Seamlessly stored into point cloud attributes, MEFI is able to be expressed as a heat-map if the underlying data are rather isolated and sparse or redundant and dense. Beyond the colour-coded quantitative features, a semantic layer is added to provide qualitative information from the data sources. Based on a versatile descriptive metadata schema (MEMoS), the 3D model resulting from the data fusion could therefore be semantically enriched by incorporating all the information concerning its digitization history. A customized 3D viewer is presented to explore this enhanced multimodal representation as a starting point for further 3D-based investigations.