Tensile Breaking Strength Research Articles

Characterization of silver nanoparticle-infused tissue adhesive for ophthalmic use

In this work, we demonstrate the successful enhancement of breaking strength, adhesive strength, and antibacterial efficacy of ophthalmic tissue adhesive (2-octyl cyanoacrylate) by doping with silver nanoparticles, and investigate the effects of nanoparticle size and concentration. Recent work has shown that silver nanoparticles are a viable antibacterial additive to many compounds, but their efficacy in tissue adhesives was heretofore untested. Our results indicate that doping the adhesive with silver nanoparticles reduced bacterial growth by an order of magnitude or more; nanoparticle size and concentration had minimal influence in the range tested. Tensile breaking strength of polymerized adhesive samples and adhesive strength between a T-shaped support and excised porcine sclera were measured using a universal testing machine according to ASTM (formerly American Society for Testing and Materials) standard techniques. Both tests showed significant improvement with the addition of silver nanoparticles. The enhanced mechanical strength and antibacterial efficacy of the doped adhesive supports the use of tissue adhesives as a viable supplement or alternative to sutures.

Radiopaque polyurethanes with flexible iodine‐containing chain extender

ABSTRACTIodinated polyurethanes (IPUs) with radiopaque property were prepared using poly(oxytetramethylene) glycol, 4,4′‐diphenylmethane diisocyanate, and a novel chain extender. The chain extender, described as N‐(1,3‐dihydroxypropan‐2‐yl)‐2,3,5‐triiodobenzamide, was synthesized in two steps from 2‐aminopropane‐1,3‐diol and 2,3,5‐triiodobenzoic acid with a high yield. A thorough study on the chemical structure, mechanical properties, radiopacity, and physiological properties of the IPUs was conducted. It is revealed that with increasing content of chain extender, the molecular weights of IPUs decreased slightly while the tensile modulus and breaking strength of IPUs increased significantly, illustrating an excellent comprehensive performance. With iodine content high to about 16 wt %, the IPU sample is equal to the aluminum plate with the same thickness in X‐ray radiopacity, meaning that the synthesized polyurethanes are promising as radiopaque materials. The oxidative degradation and cytotoxicity tests illustrated a good performance of stability and biocompatibility for the IPUs. It confirmed that the as‐synthesized IPUs are promising for biomedicine applications. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42693.

Additive manufacturing under pressure

Purpose– This paper aims to investigate the effects on material properties of layer-by-layer application of pressure during fabrication of polymeric parts by additive manufacturing (AM). Although AM, also known popularly as 3D printing, has set a new standard for ease of use and minimal restraint on geometric complexity, the mechanical part properties do not generally compare with conventional manufacturing processes. Contrary to other types of polymer processing, AM systems do not normally use (in-process) pressure during part consolidation.Design/methodology/approach– Tensile specimens were produced in Somos 201 using conventional laser sintering (LS) and selective laser printing (SLP) – a process under development in the UK, which incorporates the use of pressure to assist layer consolidation.Findings– Mechanical testing demonstrated the potential to additively manufacture parts with significantly improved microstructure and mechanical properties which match or exceed conventional processing. For example, the average elongation at break and ultimate tensile strength of a conventionally laser-sintered thermoplastic elastomer (Somos 201) increased from 136 ± 28 per cent and 4.9 ± 0.4 MPa, to 513 ± 35 per cent and 10.4 ± 0.4 MPa, respectively, when each layer was fused with in-process application of pressure (126 ± 9 kPa) by SLP.Research limitations/implications– These results are based on relatively small sample size, but despite this, the trends observed are of significant importance to the elimination of voids and porosity in polymeric parts.Practical implications– Layerwise application of pressure should be investigated further for defect elimination in AM.Originality/value– This is the first study on the effects of layerwise application of pressure in combination with area-wide fusing.

Anti-hyperbilirubinemic and wound healing activity of aqueous extract of Calotropis procera leaves in Wistar rats.

Aims:The aim of this study was to evaluate the bilirubin lowering and wound healing property of aqueous extract of Calotropis procera (AECP) leaves in Wistar rats.Materials and Methods:Albino Wistar rats of either sex were used for the study. Bilirubin lowering property of C. procera leaves was evaluated using phenylhydrazine and paracetamol as inducing agents followed by measuring the concentration of serum total bilirubin in hyperbilirubinemic rats. Wound healing property was evaluated using incision and excision models by measuring tensile breaking strength, percentage wound contractions, and epithelization days, respectively.Statistical Analysis:Statistical comparison between groups in each experiment was done with one-way analysis of variance followed by Dunnett's test.Results:AECP showed a significant (P < 0.05) decrease in concentrations of serum total bilirubin in hyperbilirubinemic rats as well as significant (P < 0.05) increase in breaking strength and percentage wound contractions with decreased epithelization period when compared to control groups.Conclusions:AECP showed significant bilirubin lowering and wound healing property in Wistar rats.

The Comprehensive Evaluation Index System of Urban Emergency Capacity Based on External DEA

Since the combined effects of the rapid urban growth and climate change, disasters such as blizzard, hurricane, earthquake and traffic jar occur in nearly every city frequently. Building an urban adaptive emergency evaluation index system is a global topic concerned by experts in recent years. It is also a top priority in current urban planning. This paper makes comprehensive research and analysis on the urban adaptive emergency capacity. Firstly, it divides the city's adap- tive strength of disaster relief into tensile strength, bending strength, abrasion resistance, fatigue strength and breaking strength etc., which is the basic of building the integrated strength grade to evaluate the city's capacity of keeping out in- cident. Secondly, it puts forward a set of scientific, complete and quantitative assessment index system (vulnerability, e- lasticity, stability, rationality and plasticity etc.) for emergency capacity which is based on the during-incident emergency evaluation theory, including Mitigability Measurement, Salvability Measurement, and Recoverability Measurement. Lastly, the paper studies the comprehensive evaluation index system of urban emergency capacity based on the external DEA, which can indicate the urban adaptive capacity of disaster relief in magic cube. Above all, the results can provide the reference for urban disaster risk management.

A model for co-isotopic signatures of evolving ground ice in the cold dry environments of Earth and Mars

The basics of the model (REGO) are summarized including diffusive water vapor transport, ice content, adsorption and the isotopic ratios of the various water species. Inclusion of a temperature and stress–strain solution is also described as are the effects of cracking when the tensile breaking strengths are exceeded. Cracking is viewed as a multi-scale phenomena, whereby the larger cracks are produced by chaining together smaller ones. After some validation, the model is applied to the upper University Valley (Antarctic Dry Valleys) data and to the Phoenix landing site at lat. 69N on Mars. For the University Valley, the model when forced by measured diurnal temperature cycles and known relative humidity reproduces some of the complex the ice content and isotope structure found in the upper University Valley ground ice cores. The model takes a few hundred years to fill the pores just under the ice table. The excess ice observed in the University Valley cores can be produced by thermal cracking combined with the diurnal temperature cycle. Time taken to achieve the observed excess ice content is of order 104years. There is limited subsurface data for the Phoenix site, but there are measured ice table depths, surface thermal properties and Met variables. There is enough to do diurnal and seasonal runs of the REGO model. As with the University Valley, the upper few tens of centimeters icing are controlled by the diurnal temperatures, largely in the warmer part of the year. The observed ubiquitous pore full ice right at the ice table could be produced from a dry soil in about 103a and the nearly pure ice patches could be produced by the cracking-diffusion mechanism in about million years, if shear stresses are included. Emplacement of ice down to ∼10m is possible using the seasonal temperature cycle and cracking. Excess ice in the upper meter could produced by the model in about 6×106a if the temperature at the Phoenix site was 10–20deg warmer.

Application Research of High-Strength Needled Filter Bag with Sea-Island Superfine Fiber

In order to improve the filtering effect of the bag filter, ultrafine sea-island fiber nonwovens is used to produce ultra-fine structure dust filter material. At the beginning, sea-island superfine fiber needle-punched nonwoven production technology is introduced. And then testament is made to tensile breaking strength, elongation at break, bursting ,air permeability, capture efficiency of dust with different diameters of 0.3μm, 0.5μm, 1μm and 3μm. At last, the performing difference of the sea-island superfine fiber ultrafiltration bag and its counterpart from the market is compared and analyzed. [1,2] The experimental results showed that the average breaking strength of Sea island superfine fiber ultrafiltration enhancement of non-woven fabric in warp direction is 1931N, its average elongation at break 32.7%, its average of Zonal breaking strength 2561N, its average elongation at break 22.6%, its bursting of average strength 1998.07N, its permeability as high as 428.62×103 m3/s, its filtering precision 82.4% under 0.3μm diameter and 100% under 3μm diameter.

Tensile Strength Test of PTFE Sew Filter Bag Line

The Passage mainly based on the tensile strength test of PTFE sew filter bag line in conditions of normal temperature, at 160°C, 180°C, 200°C respectively heating 10min and heating 24h that make conclusion of temperature, heating time and working environment on the performance of PTFE tensile breaking strength, so as to provide a basis for the PTFE sew filter bag lines work condition.

Dynamic Recrystallization Microstructure Grain Size Prediction and Performance Analysis of 7075 Aluminum Alloy Prepared by Equal Channel Angular Pressing

The process of equal channel angular pressing(ECAP)of 7075 aluminium alloy is numerically simulated using a finite element software to predict the microstructure grain size.The method of the combining application of finite element simulation and experimental analysis is explored to investigate the variation of microstructure grain size and then tensile mechanics performance test at room temperature is done between ECAP sample and initial sample,which fracture surface is watched by scanning electron microscope(SEM).The simulated results show that the grain size of sample decreases remarkably after ECAP,which reduces from 40 μm to 24.6 μm.After the experiment of ECAP the grain sizes of the sample P1,P2 and P3 are 23.8 μm,23.7 μm,23.9 μm and they are very similar.The result comparing simulative prediction with the experimental analysis demonstrates that there is a good fit in grain refinement between the two and the tensile breaking strength increases from 547 MPa to 619 MPa as well as the reduction of area increasing from 7.1% to 10.6% after ECAP.The fracture dimple is deep and great and so the strength and plasticity are improved obviously.

Silk‐inspired polyurethane containing glyalaglyala tetrapeptide. III. morphological, thermal, and mechanical features of electrosprayed and electrospun deposition

AbstractMorphological, thermal, and mechanical features of electrosprayed and electrospun deposition of the silk‐inspired polyurethane (PU) containing GlycineAlanineGlycineAlanine (GlyAlaGlyAla, the featured peptide sequence of silkworm silk fibroin) tetrapeptide, which was synthesized by the traditional liquid‐phase peptide synthesis method and the classical two‐step polymerization method using Boc‐protected amino acids and diisocyanates as starting materials, were characterized. The results show that the synthesized silk‐inspired PU dissolved in tetrahydrofuran (THF) can be easily electrosprayed or electrospun into the film form, although its molecular weight ranging from 13,000 to 15,000 is quite low. Elastomeric fibrous membranes with surface morphologies of “droplets,” “bead‐on‐string,” and “nonwoven fibers” have been obtained by electrospraying and electrospinning the silk‐inspired PU/THF solution of varying concentrations. The thermograms confirm high thermostability of the silk‐inspired PU between 350 and 400°C due to the polar peptide linkages. The tanδ peak of dynamic mechanical analysis curve corresponding to its glass transition temperatures is detected at −34.3°C. Its elongation at break is about 140–150%, and the breaking tensile strength ranges from 22 to 27 MPa, which is consistent with the data of other PUs containing l‐alanine residue. Information provided by this study can be used to better understand the correlation between the natural and man‐made silk polymers. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40245.

Development of an animal model to investigate optimal laparoscopic trocar site fascial closure

BackgroundThe rate of hernia formation after closure of 10–12 mm laparoscopic trocar sites is grossly under-reported. Using an animal model, we have developed a method to assess trocar site fascial dehiscence and the strength of different methods of fascial closure. Materials and methodsPigs (n = 9; 17 ± 2.5 lbs) underwent placement of 12 mm Hasson trocars with pneumoperitoneum maintained for 1 h. Three closure techniques (Figure-of-eight; simple interrupted; pulley) were compared with no fascial closure and to native fascia at five randomly allocated abdominal wall midline locations. Necropsy was performed on the fourth postoperative d. Statistical comparisons of tensile strength and breaking strength based on closure type and trocar location were made using ANOVA with Tukey’s tests. ResultsThe mean (SD) force (Newtons) required for fascial disruption varied significantly with closure type [Native Fascia 170 (39), Figure-of-eight 169 (31), Pulley 167 (59), Simple Interrupted 151 (27), No Closure 108 (28)]; P = 0.007. The mean force required for fascial disruption was significantly increased for Native Fascia, Figure-of-eight, and Pulley relative to No Closure (P = 0.013, P = 0.015, P = 0.023, respectively). The mean (SD) force (in Newtons) required for fascial disruption also varied significantly with location of trocar [subxiphoid 181 (43), supraumbilical 151 (23), Umbilical 146 (23), infraumbilical 168 (62), suprapubic 120 (38)]; P = 0.03. The mean force for subxiphoid location was significantly increased relative to the suprapubic location (P = 0.021). ConclusionsWe have developed a novel assessment model that reliably detects differences in fascial integrity after laparoscopic trocar placement and closure. This model will allow for further testing of various trocars and closure techniques, and facilitate hernia prevention strategies.

Fabrication of highly isotactic polypropylene fibers to substitute asbestos in reinforced cement composites and analysis of the fiber formation mechanism

ABSTRACTHighly isotactic polypropylene (PP) is currently studied as a cement‐reinforcement fiber that could potentially be substituted for asbestos because of its resistance to prolonged high‐temperature curing. The higher the isotacticity of the PP fiber is, the higher the tensile modulus and breaking strength of the cured fiber are. The PP fiber that exhibits a isotacticity of 99.6% (XI) and draw ratio of 6.0 retains a tensile modulus of 4.23 GPa, even after high‐temperature curing at 175°C for 5 h. PP fiber is cut into 6‐mm lengths and dispersed throughout a cement mixture to prepare a reinforced cement composite. The mixture is cured in an autoclave at 175°C for 5 h. The Charpy impact strength and flexural strength of the obtained cement composite tends to increase with increasing PP isotacticity. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 981‐988, 2013

High strain stretchable solid electrolytes

Wearable electronic devices that can be integrated seamlessly into clothing for monitoring and feedback need to be not only flexible, but also stretchable with low stiffness. Currently there are few solid electrolytes that are sufficiently stretchable for wearable electronic devices. Here we report stretchable solid electrolytes that can be elastically stretched more than 500% of their original length with ionic conductivities as high as 7×10−5Scm−1 and tensile breaking strengths larger than 1.5MPa. These solid electrolytes consist of poly(methyl methacrylate) chemical networks solvated by an electrochemically stable ionic liquid. A stretchable supercapacitor was demonstrated by coating a stretchable solid electrolyte with carbon nanotube electrodes.

Property Evaluation of Sound-Absorbent Nonwoven Fabrics Made of Polypropylene Nonwoven Selvages

The rapid development of textile industry at the beginning of the Industrial Revolution results in the invention of synthetic fibers. As synthetic fibers cannot be decomposed naturally, significant textile waste is thus created. Selvages, which make up the majority of our total garbage output, have a low value and thus are usually sold cheaply or outsourced as textile waste. This study aims to recycle and reclaim the nonwoven selvages which are discarded by the textile industry. The recycled polypropylene (PP) selvages, serving as a packing material, and 6 denier PP staple fibers are made into the recycled PP nonwoven fabrics. The resulting nonwoven fabrics are subsequently tested in terms of maximum tensile breaking strength, tearing strength, surface observation, thickness measurement and sound absorption coefficient.

Effect of Temperature and Humidity on Mechanical Properties of Rabbit Hair Fibers

In this paper, it tests the mechanical properties of rabbit hair fibers in different temperatures and humidity. Contrast and analysis by experiment showed the temperature exerts a great influence on the tensile strain, breaking elongation, breaking force and breaking strength. In wetting condition, the tensile strain and breaking elongation increase, but the breaking force and breaking strength decrease. The rabbit hair fiber processing with too much water will make the structure easier to break and destroy.

Tensile, Flexural and Compressive Strength Studies on Calcium Oxalate Monohydrate Urinary Stone

Calcium oxalate monohydrate (COM) is the primary constituent of the majority of stones formed in the urinary tract. Mechanical properties of renal calculi dictate how a stone interact and disintegrate with mechanical forces produced by shock wave and laser lithotripsy techniques. Tensile stresses may be more effective in some instances in disrupting material because most materials are weaker in tension than compression. Urinary stone containing COM as a major component was subjected to tensile, flexural and compressive strength studies in order to understand its mechanical properties in vitro. The calculated tensile breaking strength for the urinary stone from three tests varies from 0.57 MNm-2 to 1.52 MNm-2. The flexural strength and the flexural modulus of the urinary stone were calculated as 5.17 MNm-2 and 2.22 GNm-2 respectively while the observed compressive strength was 6.11 MNm-2. The chemical composition and the crystalline nature of the stone were verified using Fourier Transform Infrared spectroscopy and X-ray diffraction.

Alcohol acute intoxication before sepsis impairs the wound healing of intestinal anastomosis: rat model of the abdominal trauma patient

IntroductionMost trauma patients are drunk at the time of injury. Up to 2% of traumatized patients develop sepsis, which considerably increases their mortality. Inadequate wound healing of the colonic repair can lead to postoperative complications such as leakage and sepsis.ObjectiveTo assess the effects of acute alcohol intoxication on colonic anastomosis wound healing in septic rats.MethodsThirty six Wistar rats were allocated into two groups: S (induction of sepsis) and AS (alcohol intake before sepsis induction). A colonic anastomosis was performed in all groups. After 1, 3 or 7 days the animals were killed. Weight variations, mortality rate, histopathology and tensile breaking strength of the colonic anastomosis were evaluated.ResultsThere was an overall mortality of 4 animals (11.1%), three in the group AS (16.6%) and one in the S group (5.5%). Weight loss occurred in all groups. The colon anastomosis of the AS group didn’t gain strength from the first to the seventh postoperative day. On the histopathological analysis there were no differences in the deposition of collagen or fibroblasts between the groups AS and S.ConclusionAlcohol intake increased the mortality rate three times in septic animals. Acute alcohol intoxication delays the acquisition of tensile strength of colonic anastomosis in septic rats. Therefore, acute alcohol intoxication before sepsis leads to worse prognosis in animal models of the abdominal trauma patients.

Effects of prokinetic drugs on the abdominal wall wound healing of rats submitted to segmental colectomy and colonic anastomosis

To assess the effect of prokinetic agents on abdominal wall wound healing in rats submitted to segmental colectomy and colonic anastomosis. Sixty rats were randomly allocated into three groups according to the agents they would receive in the postoperative period: M (metoclopramide); B (bromopride); and C (control, saline 0.9%). Surgical procedures were performed identically in all animals, and consisted of a midline laparotomy followed by resection of a 1-cm segment of large bowel with end-to-end anastomosis. The abdominal wall was closed in two layers with running stitches. Abdominal wall samples were collected on the 3rd or 7th postoperative day for measurement of breaking (tensile) strength and histopathological assessment. There were no statistically significant differences in tensile strength of the abdominal wall scar between groups M, B, and C, nor between the three and seven days after surgery subgroups. On histopathological assessment, there were no statistically significant between-group differences in collagen deposition or number of fibroblasts at the wound site Use of the prokinetic drugs metoclopramide or bromopride had no effect on abdominal wall healing in rats submitted to segmental colectomy and colonic anastomosis.

Effect of Low Temperature Plasma Treatment on Surface Properties of Polyphenylene Sulfide Fiber

The performance of the polyphenylene sulfide fiber (PPS) was investigated by low temperature glow discharge plasma . The experimental results show that under the treatment of different plasma conditions, the PPS fiber surfaces appear the varying degree physics and chemical etching. It’s found that the friction coefficient and hydrophilicity of PPS fiber treated by low temperature plasma improve . X-ray photoelectron spectroscopy (XPS) analysis shows that the surface of PPS fiber produced etching, cross-linking, oxidation. Variations of tensile breaking strength of PPS with different parameters are analyzed.

Use of a universal testing machine for quantitative evaluation of the shattering habit of rice (Oryza sativa L.) for whole‐crop silage use

AbstractIn the breeding of rice cultivars for use for whole‐crop silage, accurate evaluation of shattering is important because its characteristics affect the digestibility of grains by animals. However, measurements of the rice grain pedicel breaking tensile strength (BTS) using a conventional shattering testing device, such as the TR‐II, are laborious. We tested a universal testing machine (UTM), a device used for physical analysis, as a labor‐saving technique for measuring rice grain pedicel BTS. A simple attachment consisting of a holding clip and a polyethylene string to the coupler was prepared to adapt the UTM for BTS measurement. There were significant (P &lt; 0.001) positive correlations between the measurements using the UTM and TR‐II across 19 rice cultivars ranging from “easy” to “very hard” shattering habit. The results indicate that the UTM is appropriate for evaluating grain‐pedicel BTS.