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The applicability of paper mulberry fiber (PM-FB), which is bast fiber, for manufacturing cellulose nanocrystals (CNCs) with high-yield was investigated. The PM-FB and hardwood bleached kraft pulp (Hw-BKP) were hydrolyzed under different sulfuric acid concentrations, reaction times, and reaction temperatures. The dependence of the CNC yield on the hydrolysis conditions and crystallinity of the raw materials was analyzed. The functional groups of the CNCs and their zeta potentials were determined. The fiber length and width of the individual CNCs were determined by transmission electron microscopy image analysis. The PM-FB showed a higher crystallinity of 86.8% compared to that of Hw-BKP and exhibited a high CNC yield of 55% under strong hydrolysis conditions. The sulfate group was introduced into the CNCs, which increased their negative charge. The fiber width of PM-FB-based CNCs (PM-CNCs) was larger than that of Hw-BKP-based CNCs (Hw-CNCs), and the aspect ratio ranged from 29.0 to 12.2 depending on the hydrolysis conditions. The yield of PM-CNCs was higher than that of Hw-CNCs under the same hydrolysis conditions. In addition, both CNCs exhibited similar quality. Therefore, PM-FB is a promising raw material for efficient CNC manufacturing.

Abstract: In the present study, calcium sulphate pigment has been synthesized experimentally from commercial grade calcium chloride. The effect of various factors on the particle size of calcium sulphate formed in a wet process and its potential application as pigment in coating recipe has been investigated. The operating factors investigated include concentration of calcium chloride solution, temperature, addition of different rheology modifiers and their optimization. The particle shape and size distribution of synthesized calcium sulphate pigment have been studied through image analyzer, scanning electron microscope (SEM) and particle size analyzer. Significant improvement was observed in various coated paper properties like brightness, whiteness, gloss, stiffness, surface strength and water retention properties of coating color with respect to conventional ground calcium carbonate (GCC) coating pigment. [Copyright &y& Elsevier]

Nanocellulose has great potential for end use in the pulp and paper industry, but its mechanical production process is often extremely energy intensive. Although various pre-treatment methods have been introduced to significantly lower the energy consumption of nanocellulose production, there still remains a great challenge to match the cost to mechanical strength performance of nanocellulose. This research investigates the relationship between energy consumption with numerous refining and homogenization cycles towards the production of high aspect ratio and low diameter nanocellulose, and whether this is necessary to achieve high strength sheets. Never-dried Bleached Eucalyptus Kraft pulp was mechanically treated with a PFI mill refiner and homogenizer. The actual homogenization energy measured on a lab scale was significantly higher than that predicted only from the simplified pressure drop equation which is inaccurately independent of homogenizer design and size. We measured two aspects of fiber quality believed to be related to sheet mechanical strength: the fiber diameter, which is inversely proportional to the surface area available for bonding, and the fiber aspect ratio, which is believed to control the efficiency of stress transfer within a network. Both refining and homogenization reduced the fiber diameter and increased the aspect ratio, but homogenization was more effective at both. There was surprisingly little correlation between the measures of fiber quality and mechanical sheet strength. All PFI mill refined samples had a tensile index of around 100 Nm/g, while additional treatment with homogenization increased this only by approximately 20%. This was despite the most heavily treated fibers (50,000 PFI revolutions and 3 homogenization passes at 1000 bar) having a median diameter of 12 nm and aspect ratio of 229 compared to the least treated fibers (10,000 PFI revolutions) with a median diameter of 31 nm and aspect ratio of 102. The most heavily treated fibers required 39,000 kWh/t of energy, a tenfold increase over the least heavily treated fibers. The results confirmed that there was small benefit, in terms of mechanical strength, of using very large amounts of energy to produce very low diameter, high aspect ratio nanocellulose fibers. [ABSTRACT FROM AUTHOR]

Thailand has a huge variability of bast fiber plants, some of which have been little researched regarding their applicability in composites. Bast fiber(bundle)s from different species were investigated and incorporated into a polylactide (PLA) matrix by injection molding. Hemp and kenaf were used as well-studied fibers, while roselle, Fryxell and paper mulberry are less extensively characterized. Tensile strength, tensile modulus and interfacial shear strength (IFSS) of single fiber(bundle)s were highest for hemp, followed by kenaf, roselle, Fryxell and paper mulberry. Despite the lower tensile strength and IFSS of paper mulberry, the highest tensile strength was achieved for the paper mulberry/PLA composite followed by hemp/PLA. Scanning electron microscope (SEM) analyses showed that the single cells in paper mulberry fiber bundles, in contrast to the other fiber types investigated, were only partially bonded to each other, which explains the lower strength of the fiber bundles. The higher aspect ratio of fiber(bundle)s of paper mulberry in the PLA composite can explain the good composite characteristics. Apart from hemp, paper mulberry shows the best reinforcing effect in the PLA matrix and offers interesting potential for composite applications. Compared to neat PLA, the tensile strength could be increased by 24% and the tensile modulus by 54%. [ABSTRACT FROM AUTHOR]

In this paper, a coupled displacement field (CDF) method was proposed to examine the free vibration behavior of a functionally graded (FG) rectangular plate with simply supported (SSSS) and clamped (CCCC) boundary conditions. The composition of the functionally graded rectangular plate is ceramic on the top and metal on the bottom. According to the power-law exponent form, the rectangular plate material properties vary continuously in the thickness direction. The trial functions signifying the displacement constituents of the cross-sections of the plate are stated in simple algebraic polynomial forms. The lateral displacement field is derived in terms of the total rotations with the help of coupling equations. By utilizing the energy formulation, the undetermined coefficients are obtained. The frequency parameters with various aspect ratios, thickness ratios, and power-law for all edges are simply supported and clamped boundary conditions are derived. To validate the numerical results, a comparison of frequency parameters is done with other literature. [ABSTRACT FROM AUTHOR]

Flexural cartridge/suspension is compliant mechanism that is used in nano precision engineering application due to its excellent advantages of providing no backlash, no friction and compact in size. These inbuilt qualities which are obtained help them to suit as a single one piece coupling that serves kinematic–mechanical behavior with small and very large deflection for variety of applications. The spiral shaped flexural cartridge is used in multiple number and multiple configurations to achieve the desired output for an application. To address the net deflection as the output (net deflection of the stack in assembled condition) it is very necessary to understand the changes which are brought in the geometrical parameters of the spiral shaped flexural cartridge/suspension. The importance geometrical parameters of spiral shape cartridge is been reported in this paper. The paper reviews the key concepts, technical advancements, identifying the most sensitive parameters of the spiral shaped flexural cartridge. This paper presents a guide to select the most appropriate parameter for the application engaged in flexural system. [ABSTRACT FROM AUTHOR]

The use of thermal energy storage (TES) contributes to the ongoing process of integrating various types of energy resources in order to achieve cleaner, more flexible, and more sustainable energy use. Numerical modelling of hot storage packed bed storage systems has been conducted in this paper in order to investigate the optimum design of the hot storage system. In this paper, the effect of varying design parameters, including the diameter of the packed bed, the storage material, the void fraction, and the aspect ratio of the packed bed, on storage performance was investigated. COMSOL Multiphysics 5.6 software has been used to design, simulate, and validate an axisymmetric model, which was then applied to evaluate the performance of the storage system based on the total energy stored, the heat transfer efficiency, and the capacity factor. In this paper, a novel-packed bed was proposed based on the parametric analysis. This involved a 0.2 void fraction, 4 mm porous media particle diameter, and Magnesia as the optimum storage material with air as the heat transfer fluid. [ABSTRACT FROM AUTHOR]

This paper presents the results of an experimental study involving 20 tests performed on elliptical concrete columns confined with externally bonded carbon fiber-reinforced polymer (EB-CFRP) laminates. The study aimed to evaluate the effects of elliptical aspect ratio (A/B) as well as confinement rigidity (number of EB-FRP layers) on confinement effectiveness. The experimental program consisted of one series of control concrete columns (unstrengthened) and three additional series, each one strengthened with one, two and three layers of EB-CFRP sheets, respectively. Furthermore, each series considered five elliptical aspect ratios (A/B) ranging from 1.0 to 1.6. Following compressive concentric tests until failure, the results were analyzed to characterize the confinement level with an increasing number of EB-CFRP layers as a function of the elliptical aspect ratio. The results show considerable enhancements in compressive strength and in the ductility of the confined columns. Furthermore, this improvement is amplified as the number of EB-CFRP layers increases, indicating a proportional relationship between the compressive strength and the number of CFRP layers. It is found that the ultimate strength of EB-CFRP-confined columns with three layers reached up to 130% compared to the control specimens. However, increasing the elliptical aspect ratio reduced the compressive strength and ductility of confined columns. This study investigated the relation between the CFRP hoop and axial strains and the elliptical aspect ratios. Moreover, through comparison, the results reveal that the prediction models proposed by the Canadian standards S806-12 and S6-19 do not capture the negative effect of the elliptical aspect ratio in confined concrete columns. [ABSTRACT FROM AUTHOR]

This paper presents a comparative analysis of fiber aspect ratios using scanning electron microscopy (SEM) and the mean field homogenization approach. The novelty of this work lies in an effective fiber length evaluation based on a comparative analysis of fiber aspect ratios using scanning electron microscopy (SEM) and the mean field homogenization approach. This makes it possible to use an electron microscope to image fiber samples corresponding to the sample size using microtomography. Molded samples and pellets of four polyamide-6 short-glass fiber-reinforced composites with mass fractions of 15%, 30%, and 50% were considered. The aspect ratio distribution measured by SEM for the investigated materials was 20.25 with a coefficient of variation of 5.1%. The fiber aspect ratio obtained based on mean field homogenization theory and the tensile curve approximation was underestimated at 13.698 with a coefficient of variation of 5.2%. The deviation between the micro- and macro-estimates can be represented as a mean effective aspect ratio of 68% with a coefficient of variation of 8.5%. The developed technology for preparing samples for SEM and automated image processing can be used to study other short-reinforced polymer composite materials. The obtained estimates can serve as a useful reference when calibrating other models of short-fiber-reinforced polymer materials. [ABSTRACT FROM AUTHOR]

In the rapidly evolving landscape of digital platforms, the need for optimizing media representations to cater to various aspect ratios is palpable. In this paper, we pioneer an approach that utilizes object detection, scene detection, outlier detection, and interpolation for smart cropping. Using soccer as a case study, our primary goal is to capture the frame salience using object (player and ball) detection and tracking using AI models. To improve the object detection and tracking, we rely on scene understanding and explore various outlier detection and interpolation techniques. Our pipeline, called SmartCrop, is efficient, and supports various configurations for object tracking, interpolation, and outlier detection to find the best point-of-interest to be used as the cropping center of the video frame. An objective evaluation of the performance of individual pipeline components has validated our proposed architecture. Moreover, a crowdsourced subjective user study, assessing the alternative approaches for cropping from 16:9 to 1:1 and 9:16 aspect ratios, confirms that our proposed approach increases the end-user quality of experience. [ABSTRACT FROM AUTHOR]

This paper aims to study the influence of the assembly units of CO2-cured iron tailings (IOT) and CO2-cured secondary aluminum ash (SAA) on the fresh high-performance concrete's (HPC's) slump flow and setting time. The mechanical properties including the flexural strength, compressive strength, the bonding strength and the dry shrinkage rate of the hardened HPC are measured. The amount of leached Cr and Zn after immersing in deionized water for 1 month~6 months is measured. The influence of the basalt fibers' volume ratio and the aspect ratio of the high-performance concrete's performance is considered. The scanning electron microscopy energy spectrums (SEM-EDS) are obtained. The results show that the slump flow and the setting time of fresh HPC are increased by the added CO2-cured SAA and IOT. The fresh HPC with 10% CO2-cured IOT and 20% CO2-cured SAA had the highest slump flow. The slump flow decreases in the form of cubic function with the placing time. The mechanical strengths and the dry shrinkage rate of HPC during the early curing ages (cured for 0.5 day~7 days) are decreased by the CO2-cured SAA and CO2-cured IOT, while the mechanical strengths at later curing ages (14 days~90 days) are increased by the added CO2-cured SAA and CO2-cured IOT. HPC with 10% CO2-cured SAA and 20% CO2-cured IOT shows the highest mechanical strengths. The amount of leached Cr and Zn is decreased by the CO2 cured SAA and IOT. The relationship between the mechanical strengths and the curing time coincides with the cubic equation. The basalt fibers with a volume ratio of 2% and aspect ratio of 1000 show the highest mechanical strengths, the lowest dry shrinkage rate and the least amount of leached Cr and Zn. CO2-cured SAA and IOT can improve the compactness of HPC's hydration products. HPC with 10% CO2-cured SAA and 20% CO2-cured IOT shows the highest compact hydration products. [ABSTRACT FROM AUTHOR]

PCC (precipitated calcium carbonate) and ground calcium carbonate have been widely used in alkaline papermaking. Unfortunately, although increasing filler level in papers can improve the paper properties such as brightness, opacity, stiffness gloss, smoothness, porosity, and printability, as well as decrease cost, some strength of the paper is negatively affected. In this research, needle-like aragonite was synthesized using Ca(OH)2 and CO2 as reactants in the presence of MgCl2 and characterized with scanning electronic microscopy (SEM) and X-ray diffraction (XRD). The physical and optical properties of the paper handsheets containing these needle-like aragonite fillers were evaluated. Results indicated that tensile strength, Z-direction tensile strength and folding endurance of the paper were improved by the needle-like aragonite crystals compared to the paper using commercial PCC (precipitated calcium carbonate) as filler. The stiffness of the paper handsheet on the machine direction was increased, but no evident difference in the cross direction was found. The improvement of paper strength mainly resulted from the twining effect between the aragonite whiskers and paper fibers. The optical properties of the paper were slightly decreased with the use of the needle-like aragonites compared to commercial PCC. These results suggest that paper cost can be decreased by increasing the content of needle-like aragonite filler while paper strength will not be decreased compared to PCC filler. [ABSTRACT FROM AUTHOR]

In this paper, the free convective flow and heat transfer in a porous rectangular enclosures filled with Cu-water nanofluid is studied and analyzed. The cavity sidewalls are exposed to a constant heat flux and the horizontal walls are assumed to be adiabatic. The governing equations describing the problem are solved using a finite difference method. The main parameters of our problem are: aspect ratio, volume fraction of nanoparticles, types of media, porosity of the medium, and Rayleigh number. The results indicate that an increase in aspect ratio from 0.1 to 0.7 leads to a significant increase of Nusselt number, which then reaches a maximum value. However, the heat transfer rate progressively decreases for aspect ratios greater than 0.7. Moreover, the addition of Cu-nanoparticles weakens the heat transfer. As a result, when the porous medium has low thermal conductivity, the solid matrix porosity becomes particularly more effective in improving heat transfer. Also, a correlation was established between the average Nusselt number and the influencing parameters. Results show that the governing parameters impact the flow regime. [ABSTRACT FROM AUTHOR]

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This paper investigates influences of welding parameters on weld bead geometry in the tungsten inert gas welding process of Zircaloy-2. Initially, a "Definitive screening design" was employed for identifying the key factors affecting weld bead geometry. Subsequently, response surface methodology was utilized to generate an experimental matrix, and experiments were conducted to analyze the effects of each welding parameter on weld bead geometry. Mathematical models were developed using analysis of variance for two-weld bead geometrical parameters, and their validity was assessed by comparing experimentally obtained values with those predicted by the model. Finally, a dimensionless parameter, the aspect ratio, indicative of the weld quality, was optimized. [ABSTRACT FROM AUTHOR]

With advancements in additive manufacturing (AM) techniques, high-quality triply periodic minimal surface (TPMS) structures can now be produced. TPMS walled heat exchangers (HX) hold significant potential for industrial applications and are receiving increasing attention. This paper explores the impact of various TPMS design variables on flow and thermal performance to optimize TPMS heat exchangers for compactness, high efficiency, and low pressure drop. The design variables examined include the type of TPMS lattice, unit cell size, wall thickness, aspect ratio, TPMS orientation, and equivalent thickness. The study reveals that the flow and heat transfer performance of TPMS structures are significantly affected by these design variables. For the Gyroid, Diamond, and SplitP lattices, performance is nearly identical when the surface-to-volume ratio is kept constant. The average velocity of the fluid in the TPMS HX should be 0.3 m/s. The corresponding Re is between 300~800. Thin wall thickness, small equivalent thickness, and flat lattice configurations can significantly reduce pressure drop while maintaining the overall heat transfer coefficient. Additionally, the angle between the flow direction and TPMS orientation can increase pressure drop. Three aluminum heat exchangers were successfully printed using an AM machine, and testing results are comparable with theoretical prediction. [ABSTRACT FROM AUTHOR]

The effects of soluble ions on the morphology and crystal growth of calcium sulfate hemihydrate whiskers are very significant. In order to gain a deeper understanding of the basic theory of regulating whiskers, this paper summarises the progress of research on the effects of different types and concentrations of soluble cations in desulfurization gypsum on the whisker preparation. The low concentration of Na+ has a small effect on the calcium sulfate hemihydrate whiskers and barely affects the morphology and surface smoothness of the whiskers. The content of K+ is suitable to be 3% (mass fraction) or below, and the higher content has a detrimental effect on the growth of calcium sulfate hemihydrate whiskers. Mg2+ makes the whisker surface more homogeneous and crystalline. And the trace amount of selective adsorption of Al3+ has no effect on the whisker length-to-diameter ratio. Similar to K+, Fe3+ also has the optimal concentration, which is lower than 2 mmol / L. Unlike the cations mentioned above, Cu2+ is not from the raw material, but is an additional ion introduced in the doping of the appropriate amount of Cu2+ is conducive to the formation of whiskers with a smooth and uniform surface. [ABSTRACT FROM AUTHOR]