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Records with Subject: Materials
1520. LAPSE:2023.24736
Drug Carriers: Classification, Administration, Release Profiles, and Industrial Approach
March 28, 2023 (v1)
Subject: Materials
Keywords: aerogels, dendrimers, drug carriers, drug delivery, hydrogels, liposomes, nanocapsules, nanoparticles, niosomes, quantum dots
This work is aimed at providing a description of the complex world of drug carriers, starting from the description of this particular market in terms of revenue. Then, a brief overview of several types of conventional and innovative drug carrier systems has been included. The types of administration routes were also analyzed, with a critical and qualitative comment on drug release kinetics and drug profile shapes. Carriers were classified according to their ability to provide a prolonged and targeted release. The concept of the therapeutic window has been presented, providing advantages of having pulsed drug release to avoid side effects to target tissues. A critical comment on the use of conventional and innovative techniques for the production of drug carriers by large industrial companies has been proposed. As a final attempt for this work, an overall unique schematization of a drug carrier production process has been added, highlighting the necessity to create a strong double link... [more]
1521. LAPSE:2023.24735
Parametric Study of Wire-EDM Process in Al-Mg-MoS2 Composite Using NSGA-II and MOPSO Algorithms
March 28, 2023 (v1)
Subject: Materials
Keywords: gap voltage, MOPSO, NSGA-II, pulse on time, wire-EDM
Al-Mg-based composite is used in producing a variety of components. To improve the machinability of the composite, MoS2 is added. For characterizing the machining of the Al-Mg-based composite, different wt.% (2, 4, and 6) of MoS2 are added as reinforcement. Wire Electrical Discharge Machining (WEDM) process is performed to analyze the kerf width and surface roughness. Due to the complex nature of the WEDM process, the necessity for its optimization through the use of innovative methods is well-proven in the process of research. Evolutionary algorithms, specifically genetic algorithm based on NSGA-II and Multiple Objective Particle Swarm Optimization (MOPSO), are used for optimizing kerf width and surface roughness. For assessing the impact of current, pulse on time, and gap voltage on kerf width and surface roughness, an analysis of the selected WEDM process parameters is performed. MOPSO takes lesser iterations as compared to NSGA-II in giving nearly the same optimal fronts for achiev... [more]
1522. LAPSE:2023.24726
Vapor Phase Modification for Selective Enrichment of Grafted Styrene/Acrylonitrile onto Carbon Nanotubes Via ATRP
March 28, 2023 (v1)
Subject: Materials
Keywords: atom transfer radical polymerization (ATRP), CNT oxidation, CNTs, grafting, SAN-grafted-MWCNT
Nitric acid vapor phase oxidation of multi-walled carbon nanotubes (MWCNTs) was proposed as a promising technique to fabricate poly styrene-co-acrylonitrile (SAN)-grafted-CNTs via atom transfer radical polymerization (ATRP). The in-situ ATRP grafting approach was successfully employed to graft polystyrene (PS), SAN and polyacrylonitrile (PAN), onto the convex surfaces of pristine MWCNTs (PCNT) and acid-functionalized MWCNTs (FCNT). Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (1H-NMR), and thermogravimetric analysis (TGA) confirmed the effectiveness of the modification via the ATRP grafting approach. The molar composition of acrylonitrile in the synthesized copolymer on the surface of CNTs for an FCNTs was calculated to be about 80% and 67.5% by 1H-NMR and TGA respectively, whereas the value is lower for PCNTs. Morphological studies showed that SAN-grafted FCNTs exhibit rougher surface morphology compared to the SAN-grafted PCNTs. Moreover, the high... [more]
1523. LAPSE:2023.24722
Study of Amine Functionalized Mesoporous Carbon as CO2 Storage Materials
March 28, 2023 (v1)
Subject: Materials
Keywords: Adsorption, amine-based adsorbents, Carbon Dioxide Capture, ethylenediamine, mesoporous carbon, triethylenetetramine
Carbon sequestration via the carbon capture and storage (CCS) method is one of the most useful methods of lowering CO2 emissions in the atmosphere. Ethylenediamine (EDA)- and triethylenetetramine (TETA)-modified mesoporous carbon (MC) has been successfully prepared as a CO2 storage material. The effect of various concentrations of EDA or TETA added to MC, as well as activated carbon (AC), on their CO2 adsorption capacity were investigated using high-purity CO2 as a feed and a titration method to quantitatively measure the amount of adsorbed CO2. The results showed that within 60 min adsorption time, MCEDA49 gave the highest CO2 capacity adsorption (19.68 mmol/g), followed by MC-TETA30 (11.241 mol/g). The improvement of CO2 adsorption capacity at low TETA loadings proved that the four amine functional groups in TETA gave an advantage to CO2 adsorption. TETA-functionalized MC has the potential to be used as a CO2 storage material at a low concentration. Therefore, it is relatively benign... [more]
1524. LAPSE:2023.24719
Microstructure Evolution and Hot Deformation Behavior of a CuNiSn Alloy
March 28, 2023 (v1)
Subject: Materials
Keywords: CuNiSn alloy, hot deformation behavior, microstructure evolution
The hot deformation behavior of Cu-20.0Ni-5.0Sn-0.25Zn-0.22Mn was investigated using a Gleeble-3500 thermal simulator with a temperature range from 720 °C to 880 °C and a strain rate range from 0.001 s−1 to 1 s−1. The results show that the flow stress increased with the increase of the strain rate and the decrease of the temperature. The constitutive equation of the alloy was established based on the peak flow stress. Figures of the power dissipation efficiency and flow instability with the variable of the true strain from 0.2 to 0.8 displayed the dynamic change of power dissipation efficiency and the instability area. The domain of 730−770 °C and 0.001−0.01 s−1 possessed a power dissipation efficiency over 40% throughout the whole deformation. The flow instability always appeared at a high strain rate from 0.1 s−1 to 1 s−1 during the whole deformation process. The nucleation site of the dynamic recrystallization generally appeared along the grain boundaries, indicating the discontinuo... [more]
1525. LAPSE:2023.24718
The Development of a Liquid Chromatography High-Resolution Mass Spectrometric Method for Apixaban Quantification in Dried Plasma Spots in Parallel Reaction Monitoring Mode
March 28, 2023 (v1)
Subject: Materials
Keywords: apixaban, DPS, dried blood spot, dried plasma spot, high-resolution mass spectrometry, LC–HRMS, parallel reaction monitoring
This work aimed at developing and validating a rapid, sensitive, and robust method of liquid chromatography with high-resolution mass spectrometry (LC−HRMS) in parallel reaction monitoring (PRM) mode for apixaban quantification in dried plasma spots (DPSs) with a simple extraction procedure. A 25 µL sample of human plasma was placed onto Whatman 903 Protein Saver Cards and allowed to dry; 3.2 mm diameter disks were cut out from DPSs using a puncher, and 100 µL of a working internal standard solution was added to each sample. After this, they were vortexed on a shaker for 15 min at 800 rpm and 40 °C and quick centrifugation (10,000× g, 10 s), and then the extracts were transferred into a 300 µL vial for LC−HRMS. Data were acquired in PRM mode via detection of all target product ions with 10 ppm tolerance. Total analysis time was 5 min. The LC−HRMS method was validated for the 10−400 ng/mL range with R2 > 0.99. Within this range, intra- and interday variability of precision and accuracy... [more]
1526. LAPSE:2023.24705
Techno-Economic Analysis of a Process for the Aqueous Conversion of Corn Stover into Lactic and Levulinic Acid through Sn-Beta Catalysis
March 28, 2023 (v1)
Subject: Materials
Keywords: lactic acid, levulinic acid, renewable chemicals, renewable fuels, Technoeconomic Analysis
A readily available source for renewable fuels and chemicals is corn stover, which consists of the leftover stalks, leaves, husks, and cobs from the corn plant and makes up nearly half of the yield of a corn crop. Common practice is to pretreat it with sulfuric acid to break down the hemicellulose, releasing xylose, followed by enzymatic hydrolysis to convert the cellulose into glucose. Using a Sn-Beta catalyst, it is possible to convert these monomeric sugars into lactic, levulinic, formic, and acetic acids. This paper presents the results of a techno-economic analysis (TEA) of the commercial feasibility of producing these acids from corn stover. Two preliminary process designs were evaluated which represent two separate reaction yields: a balanced yield of both lactic and levulinic acids and the yields from a co-catalysis with CaSO4 to produce primarily lactic acid. Both process designs are scaled to process 230,000 MT/year of corn stover. An AACS Class 4 factored broad capital cost... [more]
1527. LAPSE:2023.24702
Hydroxy-tyrosol as a Free Radical Scavenging Molecule in Polymeric Hydrogels Subjected to Gamma-Ray Irradiation
March 28, 2023 (v1)
Subject: Materials
Keywords: citrate buffer hydrogel, hydrogel, hydroxy-tyrosol, irradiation-induced cross-linking, phosphate buffer hydrogel, polyethylene oxide-based hydrogel
Biomedical engineering is employing hydrogels with increasingly exciting possibilities for the treatment and regeneration of pathologically altered, degenerated, or traumatized tissues. Still, the sterilization processes may undesirably change the chemical and physical properties of hydrogels through cross-linking reactions. This work aims to characterize a new method of producing polyethylene oxide (PEO) hydrogels exploiting hydroxy-tyrosol (HT), an anti-oxidant molecule derived from olive leaf and olive oil, as a free radical scavenger to either prevent or limit gamma-ray-induced cross-linking. For this purpose, we produced hydrogels with PEO with two different buffer solutions (phosphate and citrate), varying HT concentration. We analyzed hydrogel preparations before and after gamma-ray irradiation, assessing the viscosity through rheological analysis and the chemical changes through IR analysis. We performed high-performance liquid chromatography (HPLC) analysis to measure residual... [more]
1528. LAPSE:2023.24700
Preparation and Characterization of Two Different Liposomal Formulations with Bioactive Natural Extract for Multiple Applications
March 28, 2023 (v1)
Subject: Materials
Keywords: encapsulation efficiency, film hydration method, liposomes, phospholipids, Stellaria media (L.) Vill., Zeta potential
Liposomes continue to attract great interest due to their increased bioavailability in the body and because the substances encapsulated are protected while maintaining their effectiveness. The aim of this study is to obtain “giant” liposomes by lipid film hydration using a preparation formula with two different phospholipids, phosphatidylcholine (PC) and phosphatidylserine (PS). Firstly, the macro- and microscopic characterization, total phenols content and antioxidant capacity of the plant Stellaria media (L.) Vill. were assessed. Then, Stellaria media (L.) Vill. extract was encapsulated in both formulations (PCE and PSE) and the liposomes were characterized according to their morphology, size distribution and Zeta potential using optical microscopy and dynamic light scattering. The encapsulation efficiency (EE%) was determined using the Folin−Ciocalteu method and the values of both formulations were compared. PC and PCE liposomes with a diameter between 712 and 1000 nm and PS and PSE... [more]
1529. LAPSE:2023.24698
A Study on Lap Joint Welding of Thin Plate ASTM F1684 Using Fiber Laser Welding
March 28, 2023 (v1)
Subject: Materials
Keywords: ASTM F1684, fiber laser welding, lap joint welding, tensile strength
The International Maritime Organization (IMO) has developed stricter regulations on emission standards for sulfur oxides, etc., and the demand for Liquefied Natural Gas (LNG) is increasing as an alternative to satisfy these standards. This study relates to fiber laser welding, an approach which offers high-speed welding and low welding deformation for ASTM F1684, which has a low coefficient of thermal expansion (CTE) even in a cryogenic environment. In this study, through three preliminary experiments using 0.25 mm thick Invar, the conditions required to secure sufficient penetration depth and back bead were identified. Through the cross-sectional observation analysis, the welding conditions without defects were identified and the trend of penetration shape according to increasing welding speed was identified. Following a lap joint laser welding experiment under the secured conditions, the mechanical properties were evaluated through the shear strength test and the heat influence range... [more]
1530. LAPSE:2023.24691
The Role of Nanodispersed Catalysts in Microwave Application during the Development of Unconventional Hydrocarbon Reserves: A Review of Potential Applications
March 28, 2023 (v1)
Subject: Materials
Keywords: asphaltenes, Catalysis, electromagnetic heating, heavy oil, in-situ upgrading, microwave, nano-metal particles, transitional metals
Electromagnetic impact on oil reservoir manifests itself in various physical and chemical phenomena and attracts a significant scientific and technological interest. Microwave (MW) radiation heating can be more efficient for the oil recovery than heat transfer by convection or by thermal conduction. MW influence can also lead to significant changes in the physicochemical and rheological properties of oil caused by chemical processes of transformation of the oil high-molecular components such as resins and asphaltenes. The efficiency of transition-metal catalysts applied for the in-situ conversion of hydrocarbons directly in the reservoir might be significantly increased by exposing the oil formation to MW radiation. Actually, transition metals nanoparticles and their oxides are considered as active absorbers of MW radiation and; therefore, they can be used to intensify MW impact on the reservoir. Catalyst particles dispersed in the formation provide enhanced MW sweep. Taken together, t... [more]
1531. LAPSE:2023.24682
Enzymatic Synthesis of Poly(alkylene succinate)s: Influence of Reaction Conditions
March 28, 2023 (v1)
Subject: Materials
Keywords: aliphatic polyester, Candida antarctica, enzymatic polycondensation, enzyme activity, poly(butylene succinate)
Application of lipases (preferentially Candida antarctica Lipase B, CALB) for melt polycondensation of aliphatic polyesters by transesterification of activated dicarboxylic acids with diols allows to displace toxic metal and metal oxide catalysts. Immobilization of the enzyme enhances the activity and the temperature range of use. The possibility to use enzyme-catalyzed polycondensation in melt is studied and compared to results of polycondensations in solution. The experiments show that CALB successfully catalyzes polycondensation of both, divinyladipate and dimethylsuccinate, respectively, with 1,4-butanediol. NMR spectroscopy, relative molar masses obtained by size exclusion chromatography, MALDI-TOF MS and wide-angle X-ray scattering are employed to compare the influence of synthesis conditions for poly(butylene adipate) (PBA) and poly(butylene succinate) (PBS). It is shown that the enzymatic activity of immobilized CALB deviates and influences the molar mass. CALB-catalyzed polyco... [more]
1532. LAPSE:2023.24678
Plastic Bending at Large Strain: A Review
March 28, 2023 (v1)
Subject: Materials
Keywords: bending tests, bending under tension, plastic bending, pure bending, semi-analytic solutions
Finite plastic bending attracts researchers’ attention due to its importance for identifying material properties and frequent occurrence in sheet metal forming processes. The present review contains theoretical and experimental parts. The theoretical part is restricted to analytic and semi-analytic solutions for pure bending and bending under tension. The experimental part mainly focuses on four-point bending, though other bending tests and processes are also outlined.
1533. LAPSE:2023.24675
Influence of Loading Rate on the Energy Evolution Characteristics of Rocks under Cyclic Loading and Unloading
March 28, 2023 (v1)
Subject: Materials
Keywords: cyclic loading and unloading, damping ratio, elastic energy index, energy evolution, loading rate, plastic strain
To analyse the effect of loading rate on the energy evolution of rocks under cyclic loading and unloading, tests on saturated limestone were conducted at loading rates of 0.15, 0.2, and 0.3 mm/min, and the evolution characteristics of plastic, elastic, dissipation, and input energies were examined under different loading rates. The results indicated that the plastic strain in the entire test was directly proportional to the loading rate. In addition, strength, residual stress, plastic energy, and dissipation energy under residual resistance were inversely proportional to the loading rate. The plastic strain exhibited a decreasing−stabilising−increasing trend, and the smaller loading rate delayed the “increasing” trend. The increasing extent of each energy exhibited the following trend: input > elastic > plastic > dissipation energy. Furthermore, the first three types of energy exhibited a slow−fast−slow−fast increase trend. The dissipation energy exhibited a fast−steady−fast−slow−fast... [more]
1534. LAPSE:2023.24665
Evaluation of Rate of Adhesion of Lactobacillus namurensis Strain GYP-74 to Porous Fine Ceramics
March 28, 2023 (v1)
Subject: Materials
Keywords: adherence, lactic acid bacteria, polyacetal, pore distribution, porous fine ceramics, probiotics
This study aimed to evaluate the ratio of adherence of lactic acid bacteria (LAB) to porous fine ceramics in order to develop a novel LAB-rich pickle container for the production of functional fermented vegetables. Some LAB were isolated from the salted rice bran used for pickling (Nukadoko in Japanese). These isolates were classified in Lactobacillus namurensis by phylogenetic analysis. Some pottery-shard (PS) samples were prepared by varying the mixing rate of polyacetal (POM) resin to clay (0−30% (v/v)) and the burning temperature (1000 °C or 1100 °C). A test of the adherence of strain GYP-74 to the PSs was performed. The results showed that the adherence rate was significantly higher in the PSs burned at 1100 °C as compared with those burned at 1000 °C. A pore distribution analysis showed that pore sizes of less than a few µm and pore sizes in the range of a few µm to a few hundred µm were mainly distributed in the PSs without and with POM, respectively. X-ray diffraction analysis... [more]
1535. LAPSE:2023.24644
Recent Advances in the Critical Heat Flux Amelioration of Pool Boiling Surfaces Using Metal Oxide Nanoparticle Deposition
March 28, 2023 (v1)
Subject: Materials
Keywords: critical heat flux, Energy Conversion, metal oxide, nanoparticle deposition, pool boiling
Pool boiling is an effective heat transfer process in a wide range of applications related to energy conversion, including power generation, solar collectors, cooling systems, refrigeration and air conditioning. By considering the broad range of applications, any improvement in higher heat-removal yield can ameliorate the ultimate heat usage and delay or even avoid the occurrence of system failures, thus leading to remarkable economic, environmental and energy efficiency outcomes. A century of research on ameliorating critical heat flux (CHF) has focused on altering the boiling surface characteristics, such as its nucleation site density, wettability, wickability and heat transfer area, by many innovative techniques. Due to the remarkable interest of using nanoparticle deposition on boiling surfaces, this review is targeted towards investigating whether or not metal oxide nanoparticles can modify surface characteristics to enhance the CHF. The influence of nanoparticle material, thermo... [more]
1536. LAPSE:2023.24623
Cryo-Mechanical Treatment and Hydrometallurgical Process for Recycling Li-MnO2 Primary Batteries with the Direct Production of LiMnPO4 Nanoparticles
March 28, 2023 (v1)
Subject: Materials
Keywords: cryo-mechanical treatment, Li batteries recycling, LiMnPO4 nanoparticles, metallic lithium
In this work, an innovative hydrometallurgical recycling route for the recovery of all the materials composing Li-MnO2 primary batteries was proposed. End-of-life batteries were mechanically treated in an innovative pilot plant where a cryogenic crushing was performed. The mechanical treatment allowed for the release of the electrodic powder contained in the batteries with the simultaneous recovery of 44 kg of steel and 18 kg of plastics from 100 kg of batteries. Electrodic powder was employed as the raw material for the synthesis of LiMnPO4 nanoparticles. To obtain the synthesis precursors, selective sequential leaching of Li and Mn was performed. Li was extracted via water washing the electrodic powder and Li2CO3 and a purity of 99% was recovered. The black mass containing Mn oxides was leached using phosphoric acid, which gave a Mn-bearing precursor solution that was directly used for the hydrothermal synthesis of LiMnPO4 nanoparticles. A preliminary materials balance of the process... [more]
1537. LAPSE:2023.24608
Comparative Study of Tubular Solar Stills with Phase Change Material and Nano-Enhanced Phase Change Material
March 28, 2023 (v1)
Subject: Materials
Keywords: distilled water, nano graphene, phase change materials, tubular solar still
This study is intended to investigate and analyze the operational performances of the Conventional Tubular Solar Still (CTSS), Tubular Solar Still with Phase Change Material (TSS-PCM) and Tubular Solar Still with Nano Phase Change Material (TSS-NPCM). Paraffin wax and graphene plusparaffin wax were used in the CTSS to obtain the modified solar still models. The experimental study was carried out in the three stills to observe the operational parameters at a water depth of 1 cm. The experiment revealed that TSS-NPCM showed the best performance and the highest yield in comparison to other stills. The distillate yield from the CTSS, TSS-PCM and TSS-NPCM was noted to be 4.3, 6.0 and 7.9 kg, respectively, the daily energy efficiency of the stills was observed to be 31%, 46% and 59%, respectively, and the daily exergy efficiency of the stills was recorded to be 1.67%, 2.20% and 3.75%, respectively. As the performance of the TSS-NPCM was enhanced, the cost of freshwater yield obtained was als... [more]
1538. LAPSE:2023.24599
Insight into Foam Pore Effect on Phase Change Process in a Plane Channel under Forced Convection Using the Thermal Lattice Boltzmann Method
March 28, 2023 (v1)
Subject: Materials
Keywords: channel, forced convection, local thermal non-equilibrium (LTNE), phase change material (PCM), pore density, porosity, REV scale simulation, thermal lattice Boltzmann method (TLBM)
In this work, the two-dimensional laminar flow and the heat transfer in an open-ended rectangular porous channel (metal foam) including a phase change material (PCM; paraffin) under forced convection were numerically investigated. To gain further insight into the foam pore effect on charging/discharging processes, the Darcy−Brinkmann−Forchheimer (DBF) unsteady flow model and that with two temperature equations based on the local thermal non-equilibrium (LTNE) were solved at the representative elementary volume (REV) scale. The enthalpy-based thermal lattice Boltzmann method (TLBM) with triple distribution function (TDF) was employed at the REV scale to perform simulations for different porosities (0.7≤ε≤0.9) and pore per inch (PPI) density (10≤PPI≤60) at Reynolds numbers (Re) of 200 and 400. It turned out that increasing Re with high porosity and PPI (0.9 and 60) speeds up the melting process, while, at low PPI and porosity (10 and 0.7), the complete melting time increases. In addition... [more]
1539. LAPSE:2023.24596
Thermogravimetric Kinetics of Selected Energy Crops Pyrolysis
March 28, 2023 (v1)
Subject: Materials
Keywords: energy crops, kinetics, lignocellulosic biomass, Miscanthus giganteus, pyrolysis, Sida hermaphrodita, Sorghum Moench, thermogravimetry
The main purpose of this paper was to compare the pyrolysis kinetics of three types of energy crops: Miscanthus giganteus, Sida hermaphrodita, and Sorghum Moench. Studies were conducted in thermobalance. Feedstock samples were heated up from ambient temperature to 600 °C under an inert argon atmosphere. Three heating rates of β = 5, 10, and 20 °C/min were applied. Reactions occurring in the given temperature ranges were grouped together into so-called lumps identified by the deconvolution of derivative thermogravimetry (DTG) curves that corresponded to biomass compositions (hemicellulose, cellulose, and lignin). For the estimation of the activation energy and pre-exponential factor, the Friedman and Ozawa−Flynn−Wall methods were used. The final kinetic parameters were determined by nonlinear regression assuming that thermal decomposition proceeded via three parallel independent reactions of the nth order. The activation energy of hemicellulose, cellulose and lignin was determined to be... [more]
1540. LAPSE:2023.24582
Electrical Detection of Degradation in Specimens of HVDC Cable Insulation
March 28, 2023 (v1)
Subject: Materials
Keywords: electric tree, electric tree capacitance, HVDC-cable insulation ageing, XLPE ageing
One of the challenges in laboratory investigation of degradation and ageing of HVDC cable insulation is related to securing, or in other words, imitating the real service environment of the material specimens. So far, the published data refer to experiments conducted in thermo-oxidative conditions, which is not the case during normal cable operation. In service, the cable insulation is protected by a metallic barrier that blocks the transfer of any substances in and out of the construction. By-products from the cross-linking reactions cannot diffuse out and any foreign substances are blocked from entering the insulation. Thus, in order to generate results that are valid, these conditions must be replicated in laboratory experiments. This contribution presents a methodology elaborated for performing ageing experiments in a hermetically sealed environment. Degradation of the material is evaluated through changes in the electrical tree inception voltage and test object capacitance over ti... [more]
1541. LAPSE:2023.24542
New Method to Evaluate the Crosslinking Degree of Resin Finishing Agent with Cellulose Using Kjeldahl Method and Arrhenius Formula
March 28, 2023 (v1)
Subject: Materials
Keywords: Arrhenius formula, crosslinking degree, delayed-cure finishing, evaluation method, Kjeldahl, nitrogen content
In anti-wrinkle finishing, the crosslinking degree of fabric is mainly determined by wrinkle recovery angle, stiffness, and viscosity, these indicators can only reflect the finishing effect from a macro perspective, which cannot reflect whether the crosslinking is sufficient, and it is difficult to quantify the crosslinking degree. In this paper, we combined the Kjeldahl method with the Arrhenius formula and proposed a method to analyze the crosslinking degree of dimethyloldihydroxyethyleneurea (two-dimensional (2D) resin) with cotton cellulose during delayed-cure finishing for the first time. The nitrogen content of completed fabrics during storage was measured by the Kjeldahl method, and the reaction rate equation of the 2D resin and cellulose under normal temperature conditions was calculated. The results show that the nitrogen content is more suitable to indicate the crosslinking degree, and the apparent activation energy was 28.271 kJ/mol and the pre-finger factor was 0.622, which... [more]
1542. LAPSE:2023.24538
High-Resolution Structure-from-Motion for Quantitative Measurement of Leading-Edge Roughness
March 28, 2023 (v1)
Subject: Materials
Keywords: blade inspection, leading-edge roughness, photogrammetry, quantitative 3D reconstruction, structure from motion, surface analysis
Over time, erosion of the leading edge of wind turbine blades increases the leading-edge roughness (LER). This may reduce the aerodynamic performance of the blade and hence the annual energy production of the wind turbine. As early detection is key for cost-effective maintenance, inspection methods are needed to quantify the LER of the blade. The aim of this proof-of-principle study is to determine whether high-resolution Structure-from-Motion (SfM) has the sufficient resolution and accuracy for quantitative inspection of LER. SfM provides 3D reconstruction of an object geometry using overlapping images of the object acquired with an RGB camera. Using information of the camera positions and orientations, absolute scale of the reconstruction can be achieved. Combined with a UAV platform, SfM has the potential for remote blade inspections with a reduced downtime. The tip of a decommissioned blade with an artificially enhanced erosion was used for the measurements. For validation, replica... [more]
1543. LAPSE:2023.24510
Effect of Oxygen for Enhancing the Gas Storage Performance of Activated Green Carbon
March 28, 2023 (v1)
Subject: Materials
Keywords: amount of oxygen group, chemical activation, gas storage, Phyllostachys bambusoides, porous activated carbon
We investigated the gas storage capacity of thermally carbonized and chemically activated Phyllostachys bambusoides (PB), which is a nature-derived green carbon with an organic porous structure. Samples were thermally treated at 900 °C for 24 h, and then were chemically activated with different amounts of KOH. The pore distribution, surface area, and H2 storage capacity were measured by N2 and H2 gas sorption, up to 847 mmHg (1.13 bar) at 77 K. The CO2 storage capacity was measured up to 847 mmHg (1.13 bar) at 298 K. The maximum gas storage was shown in the sample activated with 6 times gravimetric ratio of chemical agent. It reached 1.86 wt% for H2 and 3.44 mmol/g for CO2. We used multilateral analysis methods (XRD, XPS, Raman spectroscopy, and scanning electron microscope) to identify the factors influencing gas sorption. We found that the amount of oxygen groups influence the enhancement of gas storage capacity. Moreover, the results showed that PB-based porous activated carbon has... [more]
1544. LAPSE:2023.24506
Interface Damages of Electrical Insulation in Factory Joints of High Voltage Submarine Cables
March 28, 2023 (v1)
Subject: Materials
Keywords: cross-linked polyethylene, dielectric breakdown, electrical tree, factory joint, high voltage cable
As a key accessory of high-voltage (HV) insulated submarine cable, the factory joints of the cross-linked polyethylene (XLPE) represent an unpredictable uncertainty in cable-connecting fabrications by means of the extruded molding joint (EMJ) technique. The electrical breakdown pathways formed at the interfaces between recovery insulation and cable body under alternative current 500 kV voltages are specifically investigated by microstructure characterizations in combination with the electric field and fractal simulations. Dielectric-defected cracks in tens of micrometers in insulation interfaces are identified as the strings of voids, which dominate insulation damages. The abnormal arrangements of XLPE lamellae from scanning electron microscopy (SEM) imply that the structural micro-cracks will be formed under interface stresses. Electrical-tree inception is expedited to a faster propagation due to the poor dielectric property of interface region, manifesting as 30% lower of tree incept... [more]
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