Strength Values Research Articles

Reference values for respiratory muscle strength measured with the S‐Index Test in well‐trained athletes, e‐sports athletes and age‐matched controls

AbstractRespiratory function assessment is crucial in optimizing athletic performance, safeguarding respiratory health, and ensuring athletes can perform at their peak potential while minimizing the risk of respiratory‐related issues. The S‐Index Test is a dynamic evaluation of respiratory muscle strength. However, no comprehensive reference values regarding the S‐Index Test have been reported yet. A total of 597 participants performed the S‐Index Test. They were either well‐trained athletes (WTA), or e‐sports athletes (ESA), or age‐matched controls (AMC) groups. The differences in S‐Index Test results between sexes and for group–sex, and performance calibre tier–sex interactions were examined. The relationships between S‐Index Test results and age, anthropometric indices and training experience were assessed. Reference values for all the groups were provided. Amongst athletes, the highest values were observed in swimmers and rowers, and the lowest in figure skaters and runners. The S‐Index Test results were different for the group–sex interaction (P = 0.004, 151.6 ± 29.0 cmH2O for WTA males and 109.8 ± 21.6 cmH2O for WTA females, 136.7 ± 28.0 cmH2O for ESA males and 101.8 ± 22.0 cmH2O for ESA females, 128.7 ± 28.8 cmH2O for AMC males and 70.3 ± 24.7 cmH2O for AMC females) and higher in males than females (P < 0.001, 145.1 ± 30.5 cmH2O for males and 100.8 ± 27.6 cmH2O for females). The higher athletic level, presented as performance calibre tier, was not linked to higher respiratory muscle strength in the WTA group (P = 0.094). However, the Bonferroni correction revealed that except for the singular tier in females, there was a significant effect for all the other tiers and sexes (P < 0.001). The obtained results confirm that regardless of the level of physical activity, the anthropometric features are positively linked with respiratory muscle strength. Furthermore, age and training experience were positively correlated with the S‐Index Test results in the WTA group.

Damage and energy characteristics of coal rock combinations with inclined coal seams under axial loading

A single load compression test of rock-coal-rock assemblages (RCRs) containing coal bodies with different inclinations was carried out with the research background of mining deep, large-steep coal seams. It was found that the larger the inclination angle of the coal body in the RCR samples, the larger the compaction stage of the samples and the smaller the uniaxial compressive strength value. In addition, both the maximum acoustic emission (AE) energy of the samples and the cumulative AE energy at the moment of destruction decreased with the increase of the inclination angle of the coal body in the form of exponential relativities. Also, the input energy and ultimate elastic energy of the samples at the peak stress moment decreased with increased inclination angle of the coal body. Furthermore, both of them changed with the inclination angle of the coal body in accordance with the exponential relationship; meanwhile, when the applied load exceeded the peak strength, the dissipative energy of the RCR samples increased rapidly due to the loss of load-bearing capacity. At the peak moment, the percentage of dissipated energy of the samples increased exponentially with the increase of the inclination angle of the coal body. This study has certain reference significance for the prevention and control of dynamic disasters during the mining of large angle coal seams.

Quantitative relationship between grip strength and quality of life in the older adult based on a restricted cubic spline model.

Grip strength have been showed diverse associations with quality of life for the older adult population in the literature, still there is lack of evidence of the threshold value of grip strength for maintaining good quality of life in older adults. The purpose of this study was to study the dose-effect relationship between grip strength and quality of life in the older adult, and to explore the factors affecting quality of life in the older adult, so as to provide effective theoretical basis for realizing healthy aging. A total of 105 older adult people over 60 years old were selected from 3 communities in Beijing. Grip strength was measured by hand dynamometer apparatus and quality of life was assessed by 36-item Short-Form (SF-36). On the basis of controlling confounding factors, the dose-effect relationship between grip strength and quality of life was analyzed with the restricted cubic spline model. The results showed that there was a dose-effect relationship between grip strength and physical component summary (PCS) (p < 0.01). However, grip strength was not significantly associated with mental component summary (MCS) (p > 0.05). The threshold value of grip strength for male and female is 34.75 and 23.2 kg, for normal weight group and overweight and obesity group is 24.82 and 29.00 kg, for 60-69, 70-79, 80+ years group is 24.88, 23.37, and 22.97 kg, respectively. When the grip strength value is lower than the threshold value, the increase of grip strength was related to significant improvement of quality of life of the older adult, and when the grip strength value is higher than the threshold value, the quality of life can be maintained in good condition. A dose-effect relationship was found between grip strength and physical health in quality of life. Results of our study indicated that the grip strength of the older adults needed to be greater than certain threshold values to maintain good quality of life.

Experimental and numerical study on the effect of friction between crack faces on fracture parameters of hot mix asphalt concrete

This article investigates the effect of friction between crack faces in ASCB (asymmetric semi-circular bend) specimen on fracture parameters of hot mix asphalt concrete. To achieve this, fracture tests were conducted on ASCB specimens containing cracks with different angles (0, 10, 20, 30, and 40°). In addition to the fracture tests, friction tests were also performed by designing a simple fixture. Subsequently, finite element analyses were carried out, and friction coefficients between crack faces were calculated based on the results of fracture and friction tests. Furthermore, two fracture criteria, ASED (average minimum strain energy density) and MTS (maximum tangential stress), were examined under two different scenarios: assuming zero-friction and non-zero friction between crack faces to predict fracture load and fracture strength. The fracture tests showed that with an increase in the crack angle, the fracture load initially decreased up to the crack angle of 20°, and then increased. Furthermore, the friction tests revealed that an increase in the normal load led to an increase in the friction coefficient. As per finite element results, the crack face contact occurred at a crack angle of 13.1°. Hence, crack faces in the ASCB specimens with the crack angles of 20, 30, and 40° had friction, which significantly affected the fracture parameters. The results also indicated that the average error values for the MTS and ASED criteria compared to the experimental results were 22.8 % and 18.8 %, respectively, when the friction` between crack faces is ignored, and 12.4 % and 4.0 % for the scenario that the friction effect is taken into account. The ASED criterion demonstrated higher accuracy than MTS criterion. Additionally, the average error value of fracture strength predicted by the ASED criterion with assuming non-zero friction was 4 %, indicating good predictive accuracy for fracture strength.

Evaluation of dimensional stability, setting time, tensile strength, and rheological properties of kaolin clay incorporated alginate impression material

This study aims to determine and compare the dimensional stability, setting time, tensile strength, and rheological properties of kaolin clay powder-modified and unmodified alginate impression material. Commercially available alginate-based impression material was considered as a control (C) while experimental groups E-1, E-2, and E-3 were fabricated by adding 2%, 4%, and 8% of kaolin clay powder in the control, respectively. Analytical techniques were used for the characterization of the samples. A tensile strength, rheological property, dimensional stability, and setting time were recorded for control and experimental groups. FTIR analysis confirmed the presence of kaolin clay powder in all experimental groups. SEM showed a round solid structure and irregular shape particle appearance in all experimental groups as well as a control group. The dimensional stability was improved by the addition of kaolin clay powder to the alginate impression material. The percentage dimensional change at 5 min, 6, and 12 h was increased for E3 adding (8% kaolin clay powder) and decreased for the control group. The mean value of tensile strength was highest for E3 followed by E2, E1, and least in control groups. Higher Young’s Modulus and lower deformation values were measured for E3. The mean value of setting time was highest for E3 and the least was in the control group. The results for both setting time and tensile strength were very highly statistically significant (p < 0.001). The mean values of viscoelasticity, flow, and drip test were increased statistically by adding various concentrations of kaolin clay powder to the alginate impression material.

A Quasi-Isotropic Probe for High-Power Microwave Field Measurement.

In the paper, a new design of a quasi-isotropic antenna for high-power electromagnetic (EM) field measurement is presented, along with its investigation into suitability. The measuring probe is intended for assessing pulsed microwaves, which cannot be measured by available meters due to the high value of electric field strength and short pulse duration. The measurement of such a strong field is required according to guidelines for protecting people against microwave fields, especially those emitted by radars. The proposed probe is based on the concept of dipole-diode detection. To enable high-power measurement, the receiving antenna is electrically "small," allowing diode detection within the diode square-law characteristics range. Additionally, the shortened dipole length minimizes the spatial integration error, which can be significant in the case of microwave measurement. To obtain the desired antenna polarization, a new dipole geometry was proposed. Fulfilling the requirement of measuring all incident EM field polarizations, the receiving antenna was based on three dipoles arranged within a specific "magic" angular arrangement, ensuring a suitable quasi-isotropic radiation pattern. The proposed probe can operate in a frequency range from 1 GHz to 12 GHz.

Effect of graphene on mechanical and anti-corrosion properties of TiO2-SiO2 sol-gel coating

PurposeThis paper aims to explore how graphene can improve the mechanical and anti-corrosion properties of TiO2-SiO2 sol-gel coating. This sol-gel coating has been prepared on aluminum alloy substrate using graphene as both nano-filler and corrosion inhibitor.Design/methodology/approachTo examine the effect of graphene on mechanical properties of sol-gel coating, the abrasion resistance, adhesion strength and scratch resistance of coating have been evaluated. To reveal the effect of graphene on the anti-corrosion property of coating for aluminum alloy, the electrochemical impedance spectroscopy (EIS) has been conducted in 3.5 Wt.% NaCl medium.FindingsScanning electron microscopy images indicate that graphene nanoplatelets (GNPs) have been homogeneously dispersed into the sol-gel coating matrices (at the contents from 0.1 to 0.5 Wt.%). Mechanical tests of coatings indicate that the graphene content of 0.5 Wt.% provides highest values of adhesion strength (1.48 MPa), scratch resistance (850 N) and abrasion strength (812 L./mil.) for the sol-gel coating. The EIS data show that the higher content of GNPs improve both R1 (coating) and R2 (coating/Al interface) resistances. In addition to enhancing the coating barrier performance (graphene acts as nanofiller/nano-reinforcer for coating matrix), other mechanism can be at work to account for the role of the graphene inhibitor in improving the anticorrosive performance at the coating/Al interface.Originality/valueApplication of graphene-based sol-gel coating for protection of aluminum and its alloy is very promising.

Laser powder bed fusion of NbTi low-temperature superconductors

This study investigates the superconducting properties of additive manufactured in-situ NbTi alloy using laser powder bed fusion. Laser parameters were optimised for a maximum microstructural density and lowest Nb segregation fraction. These characters have been achieved at the sample built with an energy density of 3.33 J/mm2, where it shows a density value of 6.12 g/cm3, undissolved Nb fraction of 0.05 %, and randomly distributed equiaxed grains with an average size of 10–20 μm. Post-processing of the as-fabricated (AF) sample was explored as a route to collapse residual porosity and dissolve residual segregated Nb particles using hot isostatic pressing (HIP) and heat treatment, respectively. HIPing resulted in a decrease of the undissolved Nb particle fraction to 0.035 %. Heat treatment at 1250 °C for 24 h, followed by aging at 400 °C for 2 h, was found to result in the complete dissolution of Nb particles and precipitation of the ɑ-Ti phase that works as pinning centres to increase the superconducting properties. The grain size increased in both post-processes to 400–500 μm. Electrical and magnetic properties were also measured for the AF, HIP and heat-treated samples. The thermal variation of electrical resistivity showed a critical temperature (Tc) range of 9.8–9.0 K, 9.6–9.1 K and 9.9–8.8 K for the AF, HIP, and heat-treated samples, respectively, which were close to the values obtained from magnetic measurements. The critical current density (Jc) was calculated using Bean’s model employing the magnetic hysteresis loops. The AF condition showed a negligible value of Jc (5 × 10−3 kA/mm2), which improved to 0.28 kA/mm2 and 2.65 kA/mm2 for the HIPed, heat treated conditions, respectively (at 4.2 K, 5 T). Mechanical tensile testing was performed for the heat-treated sample to ensure both mechanical and superconducting properties would achieve the required performance, where achieves ultimate tensile strength value of 930 MPa, with 8 % elongation.

One-Bath One-Step Dyeing of Polyester/Cotton Blend Fabrics Through Lipase Enzyme Surface Modification

ABSTRACT In this study, based on lipase enzyme surface modification, low-temperature dyeing of polyester/cotton fabric with reactive dyes was researched to achieve a one-bath one-step dyeing method. The Box-Behnken method was used to conduct the experiment and determine factors. For surface modification, lipase concentration, reaction time, and treatment temperature were considered, whereas for the dyeing process, reactive dye concentration, dyeing time, and dyeing temperature were taken into account to measure color strength. A treatment temperature of 30°C, a lipase enzyme concentration of 14 w/v %, and a treatment time of 50 min were shown to be ideal or optimum surface treatment parameters for lipase enzyme surface modification. The optimal or ideal conditions for the dyeing process were a reactive dye concentration of 2.13 w/v%, dyeing time of 50 min, and dyeing temperature of 66°C, giving a color strength value of 3.02. Lipase enzyme-modified polyester/cotton (p/c) blend fabrics provide color fastness that is all over grades 3–4, including washing fastness, rubbing fastness, perspiration fastness, and light fastness. The outcomes raise the prospect of developing a new technique for dying polyester/cotton blend fabric in a single bath using a single dye class that is typically employed for dying textiles made of cellulosic material.

Progressive bearing failure analysis and strength prediction method for the initial assembly and tensile process of composite bolted joints

Composite bolted joints have extensive application in aerospace and marine equipment. Failure analysis and strength prediction are crucial steps in the design of composite bolted joints. This study proposes a method that can accurately analyze the progressive bearing failure and static strength of composite bolted joints under different initial assembly parameters. This method first obtains an accurate initial assembly state based on the high-fidelity finite element model with detailed thread structure. Then it uses this as an input to analyze the progressive bearing failure process and the bearing strength value. Using the above method, the formation and evolution mechanism of the tightening yielding phenomenon during the assembly process are analyzed. And the influence of the two key assembly parameters, washer type and initial bolt tension, on the bearing strength of composite bolted joints is analyzed. The experimental results verify the effectiveness and accuracy of the simulation methods and results.

Application of Linear Algebra in Image Processing for Medical Electronics

A very important part of medical electronics is the use of linear algebra in picture processing to improve the accuracy of diagnosis, treatment plans, and medical study. This abstract talks about the basic ideas and real-world uses of linear algebra in this area, showing how important it is for improving healthcare tools. Linear algebra gives us a strong way to change and understand pictures, which is very important in many types of medical imaging, like MRI, CT scans, ultrasound, and digital pathology. Images and how they are represented and changed are two of the most basic uses of linear algebra. A lot of the time, images are shown as matrices or tensors, where each part is a pixel strength or color value. Linear changes, like translations, rotations, and scaling, are needed to line up pictures, fix errors, and make sure that image data is the same across all modes. In medical image analysis, linear algebra methods like eigenanalysis and matrix decomposition (for example, Singular Value Decomposition) are also used to get information from images and make them simpler. These techniques help doctors and researchers find important patterns, oddities, and structures in pictures, which makes automatic analysis and disease classification easier. Medical image registration is a very important step for lining up pictures from different sources or places in time. Linear algebra makes it easier to figure out transformation matrices that get the best spatial alignment. This is very important for continuous studies and tracking of treatment, where exact comparison and analysis depend on perfectly aligned images. Linear algebra is also very important in methods for improving and fixing images. For example, filtering processes based on convolution matrices are used to get rid of noise, boost contrast, and bring out features in medical pictures, which makes them easier for doctors to see and understand. In computer imaging and tomography, linear algebra makes it possible to rebuild three-dimensional structures from two-dimensional picture slices. This makes it possible to see internal details and diseases more clearly. Overall, combining linear algebra with image processing in medical electronics not only makes medical pictures better and easier to understand, but it also leads to new diagnosis tools and treatment plans. Employing mathematical methods to pull useful data from large sets of images helps healthcare professionals make better choices, which ultimately leads to better patient results and progress in medical study.

Microstructure Characteristics and Mechanical Properties of Grey Cast Iron at Varied Ferrosilicon Addition

Inoculation is an essential metallurgical route for controlling solidification conditions of cast iron, consequently, in this study, the influence of varied percent ferrosilicon (FeSi) addition on microstructure and mechanical properties of grey cast iron (GCI) was investigated. A 50Kg capacity rotary furnace was used to melt the charge (Auto engine block scrap, graphite, ferrosilicon (FeSi) and limestone). The casting was produced in a greensand mold with wooden rectangular pattern of length 50 mm and breadth 30 mm. Chemical compositions and carbon equivalent values (CEVs) of the samples were determined, using Optical emission spectrometry (AR 4 metal analyzer) and the expression respectively. Microstructures of the samples were obtained, using metallurgical microscope (model number NJF-120A). The tensile and hardness properties were measured, using Universal tensile tester and Rockwell hardness tester respectively. From the results, C and Si were the major elements. Other trace elements were Mn, P, S and Al. CEVs of both the control and inoculated samples were less than 4.3%. Microstructure of the control sample was comprised of primary dendrites and graphite flakes, while those of the inoculated samples were characterized by varied amount of more developed primary dendrites, longer graphite flakes and austenite dendrites. Also, a number of small MnS particles were observed in relative amount within the microstructures. Tensile and hardness properties of the FeSi inoculated samples were superior to the control sample. Highest tensile strength and hardness values of 76.62 MPa and 99.89 HRB respectively were obtained at the optimum inoculation of 1.5 wt. % FeSi.

Evalution of shear bond strength of brackets bonded using different hydrophobic and hydrophilic adhesives: An invitro study

A review of the long history of orthodontic bonding adhesives shows that many evolutional developments have occurred from the first chemically-cured composite resins to the most recently introduced light-cured color-change adhesives. An ideal orthodontic adhesive should have adequate bond strength while maintaining unblemished enamel after debonding. Therefore, researchers have been working hard to achieve the best quality and gentlest materials for bonding orthodontic brackets.To evaluate the shear bond strength of brackets bonded using four different adhesives in both dry and in moist environment.A total of 80 orthodontically extracted premolars will be selected. They are divided into 4 equal groups of different adhesives which are further sub-divided into 2 group each (dry and in presence of moisture). All the selected teeth will be cleaned and store in saline until it use. All teeth will be mounted on acrylic block. The shear bond strength will be measured by Lloyd’s Universal testing machine. The obtained data will be statistically evaluated using SPSS22 for Windows using ANOVA test at statistical significance.: The shear bond strength of the four groups were tested with Instron universal testing machine; breaking load at which bond failure occurred was recorded and bond strength was calculated. Data obtained was compiled on MS Office Excel Sheet (2007, Microsoft Redmond Campus, Redmond. Washington, United States.)Data was subjected to statistical package for social sciences (SPSS v 21).Statistically significant difference seen between the hydrophobic and hydrophilic adhesives. In the present study we did Tukey’s post hoc test for pairwise comparison of different hydrophobic and hydrophilic adhesives. It show highly significant values. : The greatest bond strength values were achieved with TransbondXT in both dry and saliva contamination condition. These values were significantly greater than those achieved with Greengloo, RMGIC and Aqualine LC. The overall study conclude that TransbondXT was considered the feasible adhesive material for orthodontic bonding followed by Aqualine LC.

Mechanical Properties of Newly Developed Flowable Composite Derived from Rice Husk at Different Monomer Ratios

An ideal flowable composite (FC) requires good mechanical properties to fulfill its role as a dental restorative material and ensure durability and clinical efficacy, with these properties being influenced by different monomer ratios. The study aimed to evaluate the mechanical properties of the newly developed FC on Vickers hardness, flexural strength, and flexural modulus at different monomer ratios. The newly developed FC employed nanohybrid silica from rice husk and zirconia as fillers, and the ratio of urethane dimethacrylate to triethylene glycol dimethacrylate (UDMA:TEGDMA) at 20:80, 30:70, 50:50, 60:40, 80:20 and 90:10 as monomers. Filtek Supreme Ultra Flowable Restorative, Revolution Formula 2, and G-aenial Universal Flo served as control groups. The data were statistically analyzed using one-way ANOVA with post-hoc Bonferroni test. Generally, the higher UDMA ratio in the newly developed FCs exhibited higher mechanical properties. All newly developed FCs demonstrated a significant decrease in Vickers hardness than control groups. The flexural strength values at ratios of 50:50, 60:40, 80:20, and 90:10 were comparable with control groups and passed the International Organization for Standardization 4049 requirement. Meanwhile, the flexuralmodulus of the newly developed FC at the ratio of 90:10 was comparable to Revolution Formula 2. In summary, the differences in monomer ratios affect the mechanical properties of the newly developed FCs. The improved mechanical properties at ratios of 80:20 and 90:10 could potentially substitute sustainable dental restorative materials, subjected to further investigations.

Investigating the effect of MXene reinforcement on the mechanical and vibrational behaviour of honeycomb core sandwich composite structures

Honeycomb core sandwich composite panels are now being employed in various industries and possess huge potential owing to the fact that they provide almost similar properties as that of traditional metallic materials with substantial reduction in weight and are extremely corrosion resistant. MXene nanosheets have caught attention of the scientific community owing their extraordinary physical, chemical and mechanical properties. In the present work, the effect MXene reinforcement on the bending and vibrational behaviour of honeycomb cored sandwich composite structures has been investigated using experimentation and finite element (FE) modeling. The honeycomb cored sandwich plates were fabricated and samples were tested via three-point bending and vibration test under various testing conditions. The SEM images revealed that the MXene nanosheets were well dispersed within the epoxy matrix when their mixture was prepared and the homogenous dispersion was also maintained in the fabricated honeycomb core. Also, the MXene and glass fibres were found to be well bonded with the matrix. As far as bending behaviour is concerned, the sandwich structure containing MXene reinforced honeycomb core displayed superior load bearing capacity and exhibited higher values of core shear strength and face sheet bending strength at all testing temperatures. Furthermore, the reinforcement of MXene resulted in an increase in the natural frequency for all the considered modes irrespective of the end conditions. For instance, the natural frequency of the honeycomb core sandwich composite plate at first mode increased by 5.5 % and 10.2 % under CFFF and CFCF boundary conditions, respectively, upon addition of MXene.

Experimental and Numerical Characterization of the In-Plane Shear Behavior of a Load-Bearing Hollow Clay Brick Masonry System with High Thermal Performance

Modern masonry systems are generally built with hollow clay bricks with high thermal insulating properties, fulfilling the latest sustainability and environmental criteria for constructions. Despite the growing use of sustainable masonries in seismic-prone countries, there is a notable lack of experimental and numerical data on their structural behavior under lateral in-plane loads. The present study investigates the in-plane shear behavior of load-bearing masonry walls with thin bed joints and thermal insulating hollow clay blocks. Shear-compression tests were performed on three specimens to obtain information about their shear strength, displacement capacity and failure modes. The experimental characterization was supplemented by three shear tests on triplets, along with flexural and compression tests on the mortar for the thin joints. Furthermore, two Finite Element (FE) models were built to simulate the shear-compression tests, considering different constitutive laws and brick-to-brick contact types. The numerical simulations were able to describe both the shear failure modes and the shear strength values. The results showed that the experimental shear strength was 53% higher than the one obtained through Eurocode 6. The maximum shear load was found to be up to 75% greater compared to similar masonry specimens from the literature. These findings contribute to a better understanding of the potential structural applications of sustainable hollow clay block masonry in earthquake-prone areas.

Ultrasonic-magnetic coupling field preparation microstructure and properties of in-situ nano-(ZrB2+Al2O3)/6016Al composites

In this paper, an in-situ reaction system of 6016Al-Na2B4O7-K2ZrF6 was designed, and (Al2O3+ZrB2)np/6016Al in-situ dual-phase nanoparticles reinforced composites with a volume fraction of 4 vol% were prepared using the DMR method and ultrasonic-magnetic coupling field modulation. The effects of ultrasonic-magnetic coupling field regulation on the microstructure and mechanical properties of the composites were studied by XRD, Polarization, SEM, EDS, and tensile tests at room temperature and high temperature. The results show that the 6016Al-Na2B4O7-K2ZrF6 in-situ reaction system can successfully prepare in-situ dual-phase nanoparticles ZrB2 and Al2O3 with an average size of about 79.8 nm and 47.4 nm. Under the ultrasonic-magnetic coupling field, the number of particle clusters is significantly reduced, and the matrix α-Al grain size of the composite material is refined and maintained in an equiaxed state. The α-Al grain size is 63.48 μm, 55.5 % lower than the 6016Al matrix grain size. After ultrasonic-magnetic coupling field regulation, the comprehensive mechanical properties of the composite are greatly improved. The work hardening index reach 0.42, and the yield strength, tensile strength, elongation, and hardness values reach 241.27 MPa, 295.22 MPa, 23.32 %, and 79.46 HV, respectively, which are 21.4 %, 17.5 %, 50.16 %, and 21.55 % higher than those of the composite without external field regulation. Adding an ultrasonic-magnetic coupling field gives the composite material excellent deformation uniformity while having high strength and toughness.

Cure, mechanical and swelling characteristics of composites of neoprene rubber and starch from non-edible variety of dioscorea tuber

Composites of Polychloroprene rubber (CR, Neoprene rubber) reinforced with starch from non-edible variety of dioscorea tuber were prepared using three different vulcanizing systems. The cure, mechanical, solvent resistance and biodegradable characteristics of the composites were studied. The addition of starch from dioscorea tuber was found to improve CR’s tensile strength. The maximum torque value increases with the loading of filler and it was found to be the highest at 20 phr. The addition of starch from dioscorea tuber was found to improve CR’s tensile strength and highest value observed at 20 phr. Among the different curing systems studied, the modified DCP system shows maximum mechanical properties, optimum properties of the composites are at 20 phr. The values of the swelling coefficients were determined by examining the intake of the solvents N, N-dimethylformamide, acetonitrile, dimethyl sulfoxide and water by the composites. The soil burial test indicated that biodegradability of CR enhanced with the addition of starch. The findings of mechanical properties are supported by studies using scanning electron microscopy. Since starch is a naturally occurring biopolymer, adding it encourages microbial activity, which breaks down the composite components. This quality is essential for resolving plastic waste-related environmental issues. It is anticipated that the findings of this study will aid in the development of materials for specific product applications like gasoline hoses, tire sidewalls, seals, and so on.

Mechanical drivers of intrinsic foot muscle for maximum toe flexor strength in upright standing across different body size

This study aimed to evaluate maximum toe flexor strength, foot arch height, intrinsic toe flexor muscle size and foot arch stiffness among individuals with different body sizes, and to compare these variables between sitting and standing positions. Maximum toe flexor strength in sitting and standing, and intrinsic foot muscle thicknesses (flexor hallucis brevis: FHB, flexor digitorum brevis: FDB, abductor hallucis: AH and quadratus plantae: QP), were measured using a toe grip dynamometer and a B-mode ultrasound in healthy young men. FHB was thicker than AH, FDB and QP, AH was thicker than FDB and QP, and no significant difference was found between FDB and QP. Toe flexor strength was correlated with FHB and AH, and foot arch height was correlated with FHB. Toe flexor strength was greater in standing than in sitting. Stepwise multiple regression analysis identified FHB and AH as determinants of toe flexor strength in standing, and the relative muscle strength values per body weight in standing were determined by QP, foot arch index and foot arch stiffness. Overweight individuals had a decreased rate of increase in relative toe flexor strength compared to normal individuals. These results suggest that a large muscle thickness of intrinsic foot muscle a key contributor to toe flexor strength. Moreover, toe flexor muscle in upright standing could have the potential to generate force independently of intrinsic foot muscle size, but obese individuals who chronically put weight on their feet might impair the force amplification mechanism in upright standing.

Preparation and characterization of chitosan-rice starch films incorporating Amomum verum Blackw essential oil for grape preservation

The preservation of perishable food items presents a significant challenge in the food industry. In this study, we investigated the development and characterization of chitosan-starch films incorporated with A. verum essential oil for application in grape preservation. The films were prepared using a solvent casting method, and their physical and antibacterial properties were thoroughly evaluated. The films demonstrated tensile strength values ranging from 21.28 MPa to 27.64 MPa and elongation at break between 71.24% and 84.23%. The water vapor permeability values for chitosan-starch films were from 2.04 kg/Pa·s·m to 2.51 kg/Pa·s·m. In addition, the antibacterial activity of the films was assessed against Escherichia coli and Staphylococcus aureus. The results revealed notable inhibitory effects, with inhibition zones ranging from 14.41 mm to 21.00 mm. The films' efficacy in grape preservation was evaluated through storage experiments at room temperature for 9 days, comparing them with polypropylene film and unwrapped samples. The chitosan-starch films, particularly those containing 1.0% A. verum essential oil, exhibited superior performance in reducing weight loss and maintaining grape firmness compared to common packaging materials. Moreover, grapes covered with these current active bio-based films demonstrated higher antioxidant activity, indicating potential benefits for extending shelf life and preserving fruit quality. Chitosan-starch films incorporated with A. verum essential oil hold promise as effective and environmentally friendly packaging materials for grape preservation.