Tensile Strength Measurements Research Articles

Some properties and applications of the tabletability equation.

A recently derived tabletability equation mathematically describes tablet tensile strength as a function of compaction pressure. In this work, further analysis of the tabletability equation reveals that the normalized slope at the inflection point correlates well with powder plasticity, indicating its potential use as a powder plasticity parameter. Additionally, we explore applications of the tabletability equation in quantifying errors caused by a tensile strength measurement method that disregards out-of-die elastic recovery for assessing tabletability. Finally, we show that a generalized form of the tabletability equation can be used to model other parameters, such as constrained modulus, Young's modulus, and elastic recovery, as a function of compaction pressure. Future studies investigating powder compaction may find these derived properties advantageous.

Development and Characterization of Bioplastics from Straw and Rice Husk for: Effect of Addition of Glycerin, CMC, and TiO2

The development of environmentally friendly materials is crucial to mitigate the environmental impact of conventional plastics. This study focuses on developing bioplastics using rice straw and rice husks, combined with glycerine, carboxymethyl cellulose (CMC), and titanium dioxide (TiO₂). Glycerine acts as a plasticizer to enhance flexibility, CMC functions as a matrix binder, and TiO₂ serves as a reinforcing agent to improve mechanical strength. Bioplastics were produced using the casting method with specific proportions of these materials. Characterization tests included scanning electron microscopy (SEM) for morphology, biodegradability tests, water absorption analysis, and tensile strength measurements. Results revealed that the combination of rice straw and rice husks produced bioplastics with varied morphologies. TiO₂ enhanced mechanical strength and material homogeneity, though its distribution requires further optimization. Glycerine significantly increased flexibility, while CMC improved matrix cohesion. The novelty of this research lies in the integration of agro-industrial waste—rice straw and rice husks—with TiO₂, glycerine, and CMC, creating bioplastics that balance biodegradability, mechanical properties, and flexibility. This innovative approach demonstrates the potential of utilizing agricultural byproducts to produce sustainable alternatives to conventional plastics, offering customizable properties for diverse applications.

Comparison of Physical Properties of Polypropylene Sutures and Knot Method to Prevent the Slippage of Sutured Scleral Fixation

Purpose: This study compared the physical properties of 9-0 and 10-0 polypropylene sutures used in scleral-sutured posterior chamber intraocular lens (PCIOL) fixation, with a focus on knot security and methods to prevent slippage.Methods: Tensile strength measurements were performed on 10-0 and 9-0 polypropylene sutures (Prolene™) using a material testing machine (Instron 5966 Load Frame, Model 2701-065 controller; Instron Corp., Norwood, MA). Various knotting techniques were evaluated, including a single fisherman’s knot and one, three, and five overhand knots tied around the haptic of a three-piece IOL. Knot thickness and area of the surgeon’s Knot were measured using microscopy and Image J® software, with statistical analysis conducted to compare the differences between the two suture types.Results: The 9-0 polypropylene sutures exhibited a significantly higher maximum tensile strength than the 10-0 sutures, particularly with a single fisherman’s knot (0.47 N vs. 0.52 N, p = 0.007; 0.27 N vs. 0.50 N, p < 0.001). However, when multiple overhand knots were tied around the haptic, the 10-0 sutures showed increased tensile strength with more knots (0.11 N, 0.23 N, 0.33 N, p < 0.05), whereas the 9-0 sutures did not (0.06 N, 0.31 N, 0.19 N). Notably, three overhand knots provided better stability than five knots (p < 0.05). The knot area and thickness of the surgeon’s knot were significantly larger in the 9-0 sutures than in the 10-0 sutures (21,062.4 μm2 vs. 41,188.5 μm2, p < 0.001; 160.1 μm vs. 195.6 μm, p = 0.021).Conclusions: Overhand knots increased friction between the suture and IOL haptic, enhancing knot security. However, in the 9-0 sutures, the higher rigidity caused the knots to loosen more easily, decreasing the tensile strength with more knots. This study suggests that three overhand knots are optimal for securing IOL haptics using both 9-0 and 10-0 sutures.

Evaluation of ring test with reference to deformation rate and specimen geometry in assessing the tensile behaviors of granite

Ring test for indirect tensile strength measurements utilizes disc specimens with a hole at the center of the disc. Such specimens are found to limit the stresses at the specimen-platen contact and transfer the tensile stress to the upper- and lower-hole boundaries in ring specimens. Researchers observed that the tensile strength of a ring specimen tends to decrease as the ratio of the hole-radius to the disc-radius (ρ) increases. However, there has been no research on how the tensile strength derived from ring specimens varies when loaded under different quasi-static strain rates or deformation rates. The strain analysis in case of ring tests also does not seem to have gained attention. In this study, ring specimens of Malanjkhand granite (India) with varying ρ (0.13, 0.17, 0.21 and 0.25) were quasi-statically loaded at 0.5 mm/min, 1.5 mm/min and 5.5 mm/min corresponding to strain rates of 1.75 × 10−4 s−1, 5.26 × 10−4 and 1.93 × 10−3 s−1, respectively. The combined effect of the deformation rate and specimen geometry (ρ) on the indirect tensile strength and deformation behavior was investigated. The Ring Tensile Strength (RTS) is found to be higher than the Brazilian Tensile Strength (BTS). RTS shows dependency on both the geometry of the ring specimen as well as the deformation rate. The tensile Tangent Deformation Modulus (Dv) and the ratio of the horizontal strain to vertical strain, coined as Ring Strain Ratio (RSR), were estimated in this study from the tensile stress and vertical-horizontal strain data. A numerical finite element analysis was also performed in Abaqus to observe the stress distribution in both ring and Brazilian discs, where the results were found to be broadly conformable.

Investigation of Wettability, Thermal Stability, and Solar Behavior of Composite Films Based on Thermoplastic Polyurethane and Barium Titanate Nanoparticles.

Herein, composite films were produced by incorporating different amounts (1, 3, 5, and 7%) of barium titanate nanoparticles into the thermoplastic polyurethane matrix using a solution casting method. This study examined the impact of the presence and concentration of a barium titanate additive on morphologic properties, mechanical performance, thermal stability, solar behavior, and wettability of produced film samples. The films were characterized by Fourier transform infrared spectroscopy, differential scanning calorimetry, thermal gravimetric analysis, scanning electron microscope, ultraviolet-visible near-infrared spectrophotometer, water contact angle, and tensile strength measurements. In the present study, the mass loss of samples containing 7% barium titanate was 24% lower than that of the pure polyurethane reference. The increase of barium titanate rate added to polyurethane enhanced the solar reflectance property of the films, including the near-infrared region. As a prominent result, the transmittance value decreased significantly compared to the reference in the ultraviolet region, and it dropped to 3% for the highest additive concentration. The contact angle values of polyurethane films increased by 11-40% depending on the barium titanate addition ratio. The nano additive also positively affected the mechanical performance of the reference polyurethane film by slightly increasing the tensile strength values.

Improving power law fitting of root tensile strength–diameter relationships

Abstract Purpose The relationship between root tensile strengths and diameters is often fitted using power law curves. More accurate fitting methodologies were developed, investigating a) the validity of least-squares regression assumptions underlying existing methods, b) how to best quantify intra-diameter variation, and c) whether to fit in terms of tensile strength or tensile force at failure. Methods Regression and maximum likelihood estimation were used to fit various power law models. 6461 tensile strength measurements from 153 existing datasets, covering 103 different plant species, were used to compare models. Results The intra-diameter variation in root strength is proportional to the average strength at each diameter, and is best described using a gamma distribution. When using linear regression on log-transformed measurements, a mathematical correction must be used to avoid underestimating the actual strength (18% on average). Compared to fitting tensile strengths, fitting in terms of root forces at failure was less reliable; the extra emphasis this method places on the effect of large diameters roots was not appropriate because of the typical abundance of thin roots in the field relative to those tested in tension. Average power law fits were proposed for broadleaved trees, conifers, shrubs, grasses and forbs. Conclusion Power law curves should be fitted in terms of root strength rather than root forces at failure, using the newly developed fitting methods that simultaneously fit both the inter-diameter (power law) and intra-diameter variation and can account for fitting bias. This will increase the reliability of future root reinforcement predictions.

Mechanical and surface characterisation of additively manufactured polyetheretherketone for the tribo test

Purpose The additive manufacturing process, such as fused filament fabrication based on material extrusion, fabricates the samples layer-by-layer. The various parameters in the process significantly affect the dimensions, structure and mechanical properties of the fabricated parts. The purpose of this paper is to investigate the surface and mechanical properties that can affect the contact characteristics with other materials during tribological tests. Design/methodology/approach The investigation of 3D-printed Polyetheretherketone (PEEK) includes the measurement of dimensions, microhardness, surface roughness, surface energy and tensile strength to define material characteristics. The crystallinity is measured using an X-ray diffractometer to understand the hardness behaviour. Findings The printing parameters affect its surface roughness, hardness and crystallinity. This change in parameters such as layer thickness and infill density impacts mechanical properties such as hardness and surface roughness, which will influence the contact mechanism with the counter body during any tribological test. The change in a single parameter during the sample fabrication and the change in the surface and mechanical properties are observed. Research limitations/implications The material cost plays an important role in conducting numerous destructive tests, which is a major limitation to conducting parameter optimisation by varying more parameters. The study is limited to the as-fabricated samples rather than finished samples and without any heat treatment. Achieving optimal parameters is integral to the success of additive manufacturing, ensuring the production of components with consistent performance. Practical implications The study aims at the application of 3D-printed PEEK for bush or journal bearings that can be directly used in practice. The mechanical properties discussed in this paper can fill the gap between theory and practice. Social implications The research provides all fundamental properties, including the printing parameters and their effect on the dimensions and surface structure, which are required to understand the material and its use. The results are consistent as at least four samples were tested for tribological behaviour. The conclusion is updated as per suggestions. Originality/value The study outlines the relationship between the change in layer thickness and infill density with changes in surface energy, surface roughness, hardness and tensile strength. The deformation and adhesion during the friction test depend on these properties.

Synergic effect of nano sized ceramic powder of titanium dioxide and silver on AZ91D composites fabricated by friction stir processing

This study aims to observe the synergic effects of AgNPs/TiO2 on AZ91D hybrid composite fabricated via friction stir process. Nano-sized particles of titanium-di-oxide (TiO2) and silver (AgNPs) in powder form were utilized as reinforcement materials for fabricating mono and hybrid composites. The average size of the reinforcements was 80 nm. Friction stir processing (FSP) technique was done at constant parametric settings. Investigating the microstructure of the composites by optical microscope(OM) analysis showed a homogenous distribution of the incorporated particles in the AZ91D matrix. Scanning electron microscopy (SEM) analysis was done for fractography, which indicates ductile facture in all the specimens despite having any composition of reinforcements. However, rate of ductile fracture decreased with weight fraction of TiO2. Tensile strength and Micro-hardness measurements revealed enhancement in tensile properties i.e. ultimate tensile strength (UTS), yield strength(YS), percentage elongation(EL) and microhardness in all samples. The contribution of various strengthening mechanisms, i.e. Hall-patch, Orowan strengthening and thermal mismatch, were calculated for all samples and compared with actual values. Among strengthening mechanisms, Orowan strengthening is the most dominant. The modified Clyne method estimates the collective effect of various strengthening mechanisms to evaluate the theoretical YS for all samples. The maximum value of Yield strength (YS) is 175.612 MPa obtained for T-50-A-50. The maximum value for microhardness is obtained as 140.08 HV on Vickers scale for T-100-A-0 attributed to uniform dispersion of hard ceramic (TiO2) particles.

Preparation and performance comparison of low‐dielectric epoxy resins cured by naphthalene‐ and phenyl‐based active esters

AbstractThe poor dielectric properties of epoxy resins limit their application in microelectronics, and active ester curing agent is an effective means to enhance the dielectric properties of epoxy resins. However, the phenyl active ester curing resins nowadays have the problem of low mechanical properties. In this work, a novel naphthalene‐based active ester‐cured resveratrol epoxy resin system (REP/NDA) was prepared for the first time. Compared with the phenyl‐active ester‐cured epoxy resin (REP/PDA), the naphthyl‐active ester prepared epoxy resin has obvious advantages in mechanical properties. The experimental results indicated a tensile strength measurement for REP/NDA at 91.9 MPa, the tensile strength of REP/PDA was 65.3 MPa, and the tensile strength of REP/NDA was 141% of that of REP/PDA. The prepared REP/NDA epoxy resin exhibits favorable dielectric properties, evidenced by a dielectric constant of 3.02 at 10 MHz and a dielectric loss of 0.0042, very good thermal stability (T5% of 379°C), excellent water absorption (only 0.49% for 7 days from 2 to 8°C) and good dimensional stability (coefficient of thermal expansion below Tg of 77 ppm). The first synthesis of naphthalene‐based active ester curing agent offers a reference for creating new low dielectric epoxy resin materials that work out exceptionally.

Preparation and Electrical Properties of Nanocomposite Based on Epoxy Resin and Core-Shell Polyaniline/Multi-Walled Carbon Nanotubes

Nanocomposites of epoxy resin containing various concentrations of carboxylated multiwalled carbon nanotubes (C-MWCNTs) and surface modified C-MWCNTs various concentration of both C-MWCNTs and core-shell nanoparticles were prepared. The physical, mechanical and electrical properties of prepared epoxy nanocomposites were investigated using experimental evaluations such as dynamic mechanical thermal analysis (DMTA), differential scanning calorimeter (DSC), and tensile strength measurements. The results of DSC tests revealed that the introduction of nanoparticles into the epoxy resin did not have much effect on the curing system, and by adding these nanoparticles to the epoxy resin, there is no need to change the curing system. However, the released energy during of epoxy curing show a 24% increase with the introduction of nanofiller into the epoxy matrix. The results of electrical conductivity measurements indicated a higher elastic dielectric constant for nanocomposites up to 200% incomparison with neat epoxy resin. The use of these epoxy nanocomposites in modern electrical and electro-optical industries is of great practical importance.

Investigating the influence of CaCO3 nanoparticles on the performance of CO2 absorption in the PVC membrane contactors

The membrane contactor application to purify acid gases is a significant advancement in environmental protection and engineering processes. Notwithstanding the numerous privileges of membrane contactors, the wetting of the polymeric membrane is considered the main worry in developing the mentioned technology. The polymeric membrane wetting by liquid absorbents increases the membrane mass transfer resistance and decreases the gas absorption. In this study, hydrophobic PVC membranes including various amounts of CaCO3 nanoparticles were manufactured to reduce the wetting problem. The prepared membranes were evaluated using AFM, TEM, XRD, contact angle, SEM, and tensile strength measurements. The contact angle results illustrated that adding the nanoparticles enhanced the membrane contact angle; so that for nanocomposite membranes comprising 1.5 wt.% nanoparticles, the contact angle increased from about 77°–94°. Investigating the tensile strength results showed that the nanoparticle presence in the membrane structure raised the tensile strength by 10 MPa. Finally, the nanocomposite and pure membrane performance in CO2 absorption was evaluated in the system of membrane contactors. The findings exhibited that after 25 days of the gas absorption process, the permeate flux of pure membranes significantly decreased. However, the gas absorption flux in nanocomposite membranes containing 1.5 wt.% nanoparticles remained constant during this period.

A Custom-Developed Device for Testing Tensile Strength and Elasticity of Vascular and Intestinal Tissue Samples for Anastomosis Regeneration Research.

Optimizing the regeneration process of surgically created anastomoses (blood vessels, intestines, nerves) is an important topic in surgical research. One of the most interesting parameter groups is related to the biomechanical properties of the anastomoses. Depending on the regeneration process and its influencing factors, tensile strength and other biomechanical features may change during the healing process. Related to the optimal specimen size, the range and accuracy of measurements, and applicability, we have developed a custom-tailored microcontroller-based device. In this paper, we describe the hardware and software configuration of the latest version of the device, including experiences and comparative measurements of tensile strength and elasticity of artificial materials and biopreparate tissue samples. The machine we developed was made up of easily obtainable parts and can be easily reproduced on a low budget. The basic device can apply a force of up to 40 newtons, and can grasp a 0.05-1 cm wide, 0.05-1 cm thick tissue. The length of the test piece on the rail should be between 0.3 and 5 cm. Low production cost, ease of use, and detailed data recording make it a useful tool for experimental surgical research.

Evaluating the impact of specimen and punch sizes on the tensile strength of UHPC through double punch testing

Many studies have shown that direct tensile tests are fraught with numerous challenges. The Double Punch Test (DPT) is considered a more reliable alternative for evaluating tensile properties among the indirect tensile methods. While DPT is efficient and reliable, its size effect should not be overlooked. Previous studies on DPT size effects have primarily focused on specimen size, with little discussion on the impact of punch size variations. Additionally, with the evolution of construction materials, the applicability of the generalized DPT formula to new materials, such as Ultra-High-Performance Concrete (UHPC), with its exceptional strength, toughness, durability, and crack resistance, needs to be evaluated. This study conducts experimental research on UHPC, focusing on the relationship between specimen and punch sizes and their impact on tensile strength measurements. By designing experiments with 12 different specimen sizes and punch ratios, we explore the differences between actual experimental results and simplified formula calculations. Bažant's theoretical methods are also applied to analyze the size effects of specimen and punch dimensions on DPT. The results indicate that, with appropriate specimen size and punch ratio, DPT can provide tensile strength measurements closer to those of Direct Tensile Tests (DTT). It was also found that tensile strength, strain, and toughness decrease with increasing specimen size. When the ratio of UHPC specimen to punch size (d/D) is 1/3, the results align well with the predictions of the simplified formula. This indicates that the optimal punch ratio is not fixed for different specimen sizes. These findings offer valuable references for designing related experiments and improving quality control and structural performance in various engineering fields.

Milk-Based Ointment Accelerates Wound Healing: A Comparative Study in Rabbits

Background: Wound healing is a multi-stage process that restores tissue integrity following injury. While chemical treatments like phenytoin aid in healing, traditional remedies, such as milk-based applications, remain underexplored. Milk, particularly its proteins, is known for promoting tissue repair and collagen synthesis. This study evaluated the wound-healing efficacy of a milk-based ointment (MO) on open skin wounds in rabbits. Methods: Male New Zealand white rabbits were randomly assigned to six groups, including negative controls, placebo (eucerin), and 1% phenytoin, alongside three MO groups (2%, 5%, 10% concentrations). The treatments were applied twice daily for 14 days. Wound healing was assessed through macroscopic analysis, tensile strength measurement, hydroxyproline levels, and histological examination. Results: The 5% MO-treated group exhibited the fastest wound healing, achieving full closure in 15 days, outperforming both controls and the phenytoin-treated group (17 days). Hydroxyproline levels and tensile strength were significantly higher in the 5% MO group, indicating enhanced collagen production and stronger tissue regeneration. Histological analysis further confirmed accelerated epithelialization and granulation in MO-treated groups. Conclusion: The study demonstrated that milk-based ointments, particularly at a 5% concentration, significantly enhance wound healing, suggesting their potential as cost-effective, biocompatible alternatives to conventional chemical treatments like phenytoin. Further research is needed to explore clinical applications in humans.

Quantifying the effects of repeated dyeing: Morphological, mechanical, and chemical changes in human hair fibers

As hair dyeing gains popularity across all age groups, concerns about the potential damage caused by chemical treatments are also on the rise. Chemical dyes have a multifaceted impact on hair fibers, affecting their morphology, physical structure, and protein composition. In a comprehensive study, we investigated the alterations in morphological and mechanical properties, as well as the chemical composition of hair fibers following continuous dyeing. Our analysis employed various techniques, including atomic force microscopy (AFM), Fourier transform infrared (FT-IR) spectroscopy, and tensile strength measurements. To assess the cumulative damage resulting from repeated dyeing, we progressively increased the number of dyeing up to 10. Surprisingly, even a single dyeing session inflicted noticeable harm on the hair. However, the detrimental effects escalated significantly when hair underwent three or more consecutive dye treatments. While the mechanical properties and protein composition exhibited non-linear changes with increasing the number of dyeing, we observed that nanoscale damage to the cuticle surface intensified proportionally with the number of dyeing. These results highlight the critical need to consider the impacts of hair dyeing practices on both the health and the structural integrity of hair.

Spray coating of 2D materials in the production of antifouling membranes for membrane distillation

Membrane surface coatings with 2D materials have been shown to exhibit antifouling properties for water-treatment applications; however, synthesis methods currently based on vacuum filtration are not easily scalable. This study describes a scalable method for coating membranes with a range of 2D materials including graphene oxide (GO), hexagonal boron nitride (hBN), molybdenum disulphide (MoS2) and tungsten disulphide (WS2). Isopropyl alcohol solutions containing each class of the 2D flakes were spray-coated onto commercial polyvinylidene fluoride (PVDF) using a pyrolyser. The nanomaterials were secured with polydopamine (PDA) as a crosslinker in a method that could easily be integrated into a scalable roll-to-roll process. Changes in morphology, surface roughness, hydrophobicity, mechanical durability and chemical composition were evaluated using scanning electron microscopy, atomic force microscopy, contact angle, tensile strength measurements and Fourier-transform infrared spectroscopy. The 2D nanomaterials-coated membranes were tested in membrane distillation (MD) experiments over 72 h and compared to pristine PVDF and PDA/PVDF membranes. Salt rejection and MD performance stability were evaluated using feedwaters with high concentrations of humic acid (150 ppm) and paraffin oil (200 ppm) simulating simple organic wastewater from oil and gas extraction. The flux decline ratio was measured in terms of percentage permeate loss per hour (%/h), to allow for future comparisons with studies with different experimental times. The pristine PVDF membrane failed after 10 h by pore-wetting due to fouling while the PDA/PVDF membrane had the largest flux decline ratio (0.3 %/h). The membranes coated with GO and hBN had flux decline ratios orders of magnitude lower (0.0021 ± 0.005 and 0.028 ± 0.01 %/h, respectively). All membranes had a high salt rejection (>99.9 %). The GO-coated membrane was the only membrane type that was able to treat both surfactant-containing and foulant-containing feedwaters. The improved performance is attributed to the decrease in both surface roughness and hydrophobicity, which reduces the adsorption of foulants onto the membrane surface. This work shows a facile, scalable method to overcome fouling limitations in MD.

The strength of outgassed porous dust aggregates

Context. Outgassing of dust-ice aggregates plays an important role on the surfaces of cometary nuclei as well as for snow-line crossings in protoplanetary disks. Aims. To assess the stability of desiccated dust aggregates, we measured the tensile strength of silica dust samples over a wide range of volume filling factors. Methods. We produced these silica dust samples over a wide range of volume filling factors by gently evaporating dust-ice mixtures with various dust-to-ice mass ratios under vacuum conditions. The tensile strengths of these samples were then measured using the standardized Brazilian disk test. Experiments were performed in a vacuum and at room temperature but were also compared to measurements in air at room temperature and in a vacuum at elevated temperatures. Results. For spherical amorphous silica dust, we find no influence of the environmental conditions (air, vacuum, or heating) on the measured tensile strength. However, for angular crystalline silica dust we see a strong increase in tensile strength in a vacuum compared to air and an even higher increase when the samples are heated in a vacuum. For the spherical silica dust samples, we find a characteristic increase in the tensile strength with decreasing particle size. The tensile strength of samples with identical particle sizes increases strongly with an increasing volume filling factor. Extrapolation of our data to a volume filling factor of 0.1 (90% porosity) shows that a tensile strength as low as 1 Pa can be reached. Conclusions. Numerical simulations show that evaporating water ice in the subsurface layers of comets can reach gas pressures of ~1 Pa. Thus, a desiccated dust layer with a 10% volume filling factor should be detachable and released into the cometary coma. Using a relation between the tensile strength and the critical fragmentation energy, we predict the break-up speed of dust aggregates in mutual collisions as a function of the volume filling factor. Furthermore, we discuss the susceptibility of the aggregates to ram pressure. These values are relevant for protoplanetary disk research and for meteoroids entering planetary atmospheres.

Mechanical and thermal properties of glass fiber reinforced polymer-clay nanocomposites

Abstract The effect of Montmorillonite (MMT) nanoclay on static mechanical and thermal characteristcs of glass fiber-reinforced polymer (GFRP) composites is studied. The static tensile properties of epoxy/MMT nanoclay, which are important properties of GFRP composites, are investigated. The predicted stress-strain curves of epoxy with 0 and 1 wt.% of nanoclay follow experiments. The predicted elastic modulus and tensile strength of epoxy with 3 wt.% of nanoclay are 74 and 230% higher than neat epoxy. For GFRP composites with 0, 1, 3, and 5 wt.% of MMT nanoclays, the measured tensile strengths are 587, 600, 628, and 724 MPa, and flexural strengths are 626, 726, 906, and 542 MPa. For composites with former nanoclays, interlaminar shear strengths are 23, 25, 31, and 28 MPa, and Izod impact strengths are 83, 94, 207, and 145 kJ/m2. Thus, mechanical strengths of composites with 0–5 wt.% of nanoclays improve considerably than pristine sample. The predicted static tensile stress-strain curves of GFRP composites with above nanoclays follow experimental behavior. For GFRP composites with 0 and 1 wt.% of MMT nanoclays, glass transition temperatures are 91 and 101°C, and storage moduli at ambient temperature are 35 and 41 GPa. The thermal conductivities of GFRP composites with 0, 1, and 3 wt.% of MMT nanoclays at ambient temperature are 0.32, 0.36, and 0.42 W/(m·K). Thus, thermal properties of composites are affected significantly on addition of nanoclays.

Wound Healing Effectiveness of Berberis baluchistanica and Daphne oleoides Extracts Native to Pakistan

Traditionally in Turkish medicines, Berberis baluchistanica and Daphne oleoides plant are used for the treatment of rheumatism, fever, lumbago, gonorrhea, boils, snake bite antidote, piles, hemorrhoids, as laxative, ulcers and wound healing. The study objective was based on the scientific investigation of traditional claim of wound healing potential of both these wild plants extract in healthy inbreed male albino rats. The wound healing activity of both the extracts was evaluated by adopting excision and incision wound models with a topical dose of 100 mg/kg b.w /day. Wound healing process effectiveness was assessed by measuring wound contraction and epithelization period, measurement of tensile strength of healing skin and histopathological studies of granulating tissue. D. oleoides roots crude methanolic extract (CME) encouraged pronounced wound repairing process in both adopted wound models. In this case, boosted wound retrenchment rate (P < 0.001), shrinkage of epithelialization period (10.13 ± 0.11), high skin disintegration strength (410.0 ± 1.8) and remarkable enhanced granulation tissue weight (P < 0.001) were experienced in albino rats. As well as the granulation tissue histological examination exhibited more collagen with reduced inflammatory cells number propagation versus control. In B. baluchistanica stems CME treated animals, wound contraction, and granulation tissue content were not much prevailed being (P < 0.05) moderately high. The histology of the granulation tissue disclosed greater number of inflamed cells with less collagen than the D. oleoides treated animals. However, it was more amplified compared to control group. The collective research data emphasized that D. oleoides possesses significant wound management activity versus B. baluchistanica, furthermore both extracts rationalize the traditional claim to cure wounds and can be utilized in different wound healing therapies in human beings as well.

Hygrothermal Degradation of Epoxy Electrical Insulating Material-Testing and Mathematical Modeling.

The degradation of electrical insulating materials has been a subject of interest for decades as they are commonly applied in many fields of electrical engineering. Suitably modeling such a process is important since the known and well-described degradation process reveals the effect of ambient conditions, and this allows us to possibly estimate a material's remaining useful life. However, not many studies are dealing with the effect of the hygrothermal degradation of impregnating mono-component epoxy resins in the context of electrical engineering. Therefore, this study deals with this issue and discusses both the dielectric response (based on the measurement of relative permittivity, dissipation factor, and dielectric strength) and the mechanical response (based on measurements of tensile strength and Shore D hardness) to a hygrothermal degradation experiment. In addition, the results of thermal analyses are presented for the evaluation of the pristine specimen manufacturing process and possible post-curing processes. Furthermore, this study presents several methodologies for modeling the degradation process, including a novel methodology in this area based on Bayesian experimental design. As an outcome, mechanical parameters are proven to be specific in terms of the actual condition of the material and the Bayesian enhanced degradation model seems to be superior to the conventional evaluation methods in this particular study.