Traction Test Research Articles

Numerical analysis of lug effects on tractive performance of off-road wheel by DEM

This paper presents the lug effects of off-road wheel in terms of lugs’ height, type, intersection and central angle. To improve the tractive performance of transport vehicles and equipments operating on dry sands nearshore, this paper numerically presents the wheel–sand interaction by the discrete element method (DEM), which is better dynamically accurate than FEM in the study of incompact terrain-like sands. According to the physical properties presented by the triaxial test, the appropriate parameters are selected to establish and verify the simulation model of the sand sample. On that basis, numerical traction tests are orthogonally carried out to analyze the different lug effects on tractive performance. It is concluded from the analysis that the intersection of lugs has no effect on tractive performance. Lugged wheel shows the best tractive performance, while the central angle of lugs reaches 24°. Both the height and type of lugs can improve the drawbar pull; the former may increase the tractive efficiency under good road conditions with low slip, while the latter is capable of influencing the efficiency under bad road conditions with high slip.

Is the Dresden technique a mechanical design of choice suitable for the repair of middle third Achilles tendon ruptures? A biomechanical study

ObjectiveTo compare the mechanical failure of the Dresden technique for Achilles tendon repair with the double modified Kessler technique controlled repair technique. The maximum resistance of the two repair techniques are also compared. Material and methodsA total of 30 Achilles tendon ruptures in bovine specimens were repaired with an Ethibond® suture to 4.5cm from the calcaneal insertion. Each rupture was randomly distributed into one of two surgical groups. After repair, each specimen was subjected to a maximum traction test. The mechanical failure (tendon, suture, or knot) rates (proportions) were compared using the exact Fisher test (α=.05), and the maximum resistances using the Student t test (α=.05). ResultsThere was a difference in the proportions of mechanical failures, with the most frequent being a tendon tear in the Dresden technique, and a rupture of the suture in the Kessler technique. DiscussionThe repair using the Dresden technique performed in the open mode, compared to the Kessler technique, has a more suitable mechanical design for the repair of middle third Achilles tendon ruptures on developing a higher tensile resistance in 58.7%. However, its most common mechanical failure was a tendon tear, which due to inappropriate loads could lead to lengthening of the Achilles tendon.

Hypnotic effect of the essential oil from the leaves of Myrtus communis on mice.

BackgroundMyrtus communis has been suggested as a sleep aid in unconventional medicine. Moreover, previous studies have also indicated its sedative- and hypnotic-like activity. In this study, the hypnotic effect of M. communis was investigated.MethodsEssential oil (EO) of M. communis (600, 800, and 1,000 mg/kg) was given orally to Swiss albino mice of both sex, and the hypnotic effect was evaluated. In addition, the EO of M. communis (500, 600, 800, and 1,000 mg/kg) was administered orally to Swiss albino mice of both sex 60 minutes prior to pentobarbital injection (50 mg/kg). Latency to sleep and sleep duration were recorded. The effect of the EO on motor coordination and muscle relaxation was evaluated using chimney and traction tests, 60 and 90 minutes after administration of the respective doses of the EO, respectively.ResultsThere was no induction of hypnosis as the presence of the righting reflex was intact. However the EO prolonged pentobarbital-induced sleeping time and there was also 50% negative response on the chimney and traction test in a dose dependent manner.ConclusionThe EO of M. communis did not produce a hypnotic effect, but it potentiated a hypnotic effect with significant central nervous system depressant activity.

¿Es la técnica Dresden un diseño mecánico de elección apropiado para la reparación de roturas de tercio medio del tendón de Aquiles? Ensayo biomecánico

ObjectiveTo compare the mechanical failure of the Dresden technique for Achilles tendon repair with the double modified Kessler technique controlled repair technique. The maximum resistance of the two repair techniques are also compared. Material and methodsA total of 30 Achilles tendon ruptures in bovine specimens were repaired with an Ethibond® suture to 4.5cm from the calcaneal insertion. Each rupture was randomly distributed into one of two surgical groups. After repair, each specimen was subjected to a maximum traction test. The mechanical failure (tendon, suture, or knot) rates (proportions) were compared using the exact Fisher test (α=.05), and the maximum resistances using the Student t test (α=.05). ResultsThere was a difference in the proportions of mechanical failures, with the most frequent being a tendon tear in the Dresden technique, and a rupture of the suture in the Kessler technique. DiscussionThe repair using the Dresden technique performed in the open mode, compared to the Kessler technique, has a more suitable mechanical design for the repair of middle third Achilles tendon ruptures on developing a higher tensile resistance in 58.7%. However, its most common mechanical failure was a tendon tear, which due to inappropriate loads could lead to lengthening of the Achilles tendon.

Experimental analysis of adhesion phenomena in fibre-reinforced glass structures

Adhesion phenomena in hybrid glass structures made of glass and composite material are of critical importance in order to achieve high performance. As a contribution to the study of this topic, an experimental and analytical investigation was performed. It looked into the adhesion phenomena of two different composites, such as GFRP (Glass Fibre Reinforced Polymers) and SRP (Steel Reinforced Polymers), using different types of resins and various interface geometries. The experiment was carried out on samples subjected to shear traction tests, in order to examine the load transfer mechanism and the failure mode of the adhesive joint, to evaluate the optimal bond length and to perform a validation using substantiated theories. A formulation studied on the basis of the experimental results is also proposed herein to evaluate debonding resistance and the optimal bond length.

The provocative radiographic traction test for diagnosing craniocervical dissociation: a cadaveric biomechanical study and reappraisal of the pathogenesis of instability

Background ContextCraniocervical dissociation is a rare but serious condition, and missed injuries have been associated with poor neurologic outcomes and deterioration. A fluoroscopic traction test is employed to interrogate the craniocervical ligaments when clinical and imaging findings are equivocal. However, no specific protocol or known parameters with respect to traction or force applied have been established. PurposeThis study sought to define the parameters of the radiographic traction test with sequential sectioning of the primary ligamentous restraints under controlled distraction of the craniocervical junction in a biomechanical model. Study DesignThis is a cadaveric biomechanical study. MethodsA custom loading apparatus applied traction forces in six specimens (O-C3) and the following ligaments were sectioned: alar, tectorial membrane, and occiput-C1 capsules to simulate varying degrees of craniocervical dissociation. Traction was applied 0 to 20 lb with fluoroscopy. Digital image analysis quantified the relative displacements of C0–C1, average craniocervical excursion, and under what load could a 2-mm craniocervical displacement be reproducibly recorded. ResultsA weight-distance table was produced and showed a marked loss of stability with sectioning of the ligaments and across all specimens in a similar pattern. Minimal translation was noted with sectioning of two of three ligaments in any order (<1–2 mm). All specimens exhibited a firm restraint to dissociation until the last of the three stabilizers was sectioned. Thus an “all-or-none” restraint to instability is present. All specimens failed at a weight of 5–10 lb (>2 mm). ConclusionsThe current knowledge base of craniocervical injuries is very limited. This study shows that the key restraints to craniocervical instability are the alar ligaments, tectorial membrane, and the atlantooccipital joint capsules. Dissociation requires the complete incompetence of all three. The craniocervical traction test reliably demonstrates instability and requires no more than 5–10 lb of traction to perform.

The surgical management of restrictive strabismus caused by thyroid-associated ophthalmopathy

Objective To investigate the clinical features of restrictive strabismus caused by thyroid-associated ophthalmopathy (TAO) and the effect of rectus tenotomy for restrictive strabismus. Methods Thirty-seven TAO patients with restrictive strabismus were collected in our hospital. For every patient, the most restricted extraocular muscles were determined by monocular cover, eye movement and passive traction test. Rectus tenotomy only or combined with shortening the antagonist mucle was performed on the most restricted one or more muscles.The position of eyes, eyes movements and diplopia were measured pre- and post-operatively. Results All the patients had good results.Thirty-two patients (86.5%) had the elimination of diplopia, significant improvement of eye movements in every direction and the strabismus angle less then 5°. Four cases had obvious improvements and one case was undercorrection. Four patients had postoperative complicated eyelid retraction. Conclusion Rectus tenotomy can effectively eliminate restrictive strabismus caused by TAO. Key words: Thyroid-associated ophthalmopathy; Strabismus, restrictive; Rectus tenotomy

The Nice knot as an improvement on current knot options: A mechanical analysis

PurposeThere is currently a wide range of suture knots used in rotator cuff repair. The purpose of this study was to compare a new type of self-locking sliding knot called the Nice knot to the self-locking and sliding Nicky's knot. MethodsNice knots and Nicky's knots were tied and subjected to mechanical testing including a pure traction stress and a series of dynamic stresses. Both knots were tied using standard braided suture and reinforced braided suture. The responses to these stresses were measured in the amount of elongation of the knot, maximum effort needed for failure, stiffness of construct and dynamic stiffness. ResultsWith both knots the standard suture had a lower amount of elongation during the dynamic tests than the reinforced braided suture. The reinforced braided suture showed superior results during maximal effort in the pure traction tests. An increased failure rate occurred due to elongation when a dynamic stress was applied to the reinforced suture in both knot types. During dynamic testing the Nice knot showed a decrease in the amount of elongation (P<0.001). ConclusionsThe Nice knot provides a sliding locking knot option which can decrease the risk of elongation during dynamic stress. Level of evidenceBasic Science Study, Biomechanical Study.

Traction force needed to reproduce physiologically observed uterine movement: technique development, feasibility assessment, and preliminary findings.

This study aimed to describe a novel strategy to determine the traction forces needed to reproduce physiologic uterine displacement in women with and without prolapse. Participants underwent dynamic stress magnetic resonance imaging (MRI) testing as part of a study examining apical uterine support. Physiologic uterine displacement was determined by analyzing uterine location in images taken at rest and at maximal Valsalva. Force-displacement curves were calculated based on intraoperative cervical traction testing. The intraoperative force required to achieve the uterine displacement measured during MRI was then estimated from these curves. Women were categorized into three groups based on pelvic organ support: group 1 (normal apical and vaginal support), group 2 (normal apical support but vaginal prolapse present), and group 3 (apical prolapse). Data from 19 women were analyzed: five in group 1, five in group 2, and nine in group 3. Groups were similar in terms of age, body mass index (BMI), and parity. Median operating room (OR) force required for uterine displacement measured during MRI was 0.8N [interquartile range (IQR) 0.62-3.22], and apical ligament stiffness determined using MRI uterine displacement was 0.04N/mm (IQR 0.02-0.08); differences between groups were nonsignificant. Uterine locations determined at rest and during maximal traction were lower in the OR compared with MRI in all groups. Using this investigative strategy, we determined that only 0.8N of traction force in the OR was required to achieve maximal physiologic uterine displacement seen during dynamic (maximal Valsalva) MRI testing, regardless of the presence or absence of prolapse.

Analgesic, Anti-inflammatory and Other Pharmacological Activities of Methanol Extract of Rhododendron campanulatum from Nepal

Aims: Rhododendron campanulatum D. Don is a plant of Ericaceae family that is found at an altitude of 3000-4200 meters. Traditionally, it has been used to cure rheumatism, hemicranias, sciatica and colds. This study aims to determine analgesic and anti-inflammatory activities and effect on gastrointestinal motility, brain function and skeletal muscle of Rhododendern campanulatum extracts in mice. Methodology: Pharmacological activities were evaluated in mice. Analgesic activity was determined by hot plate and chemical writhing methods; anti-inflammatory activity by ability to cure carrageenan induced paw edema; effect on gastrointestinal motility by charcoal meal assay, effect on brain function by locomotor activity and skeletal muscle relaxant activity by traction test. Results: Methanol extract from R. campanulatum increased the response time of mice from 6 secs

Tamizaje fitoquímico y evaluación de la actividad sobre el sistema nervioso central del extracto etanólico de Eugenia clarensis Britton &amp; P.Wilson

Context: Eugenia clarensis Britton &amp; P. Wilson is an endangered plant endemic of central region of Cuba. Aims: To perform phytochemical profile of ethanolic leaf extract of E. clarensis and evaluate its central nervous system (CNS) activity. Methods: The dried powder of leaves of E. clarensis was exhaustively extracted with ethanol by maceration. This extract underwent preliminary phytochemical analysis and these results were corroborated by the thin layer chromatographic technique. CNS effects were investigated in NMRI mice at doses 200, 400 and 800 mg/kg using Irwin test, curiosity tests and traction. Results: Phytochemical screening suggested the presence of phenols, tannins, triterpenoids, sterols, flavonoids, coumarins, quinones, resins and reducing sugar. The oral administration of this extract, in Irwin test, produced slight reduction in spontaneous motor activity and muscle tone in mice at doses of 400 and 800 mg/kg, moreover, it exhibited diuretic activity. In addiction this extract at dose 800 mg/kg decreased number of times which mice introduced its head into holes in comparison with the negative control. In the traction test, the mice treated with the extract showed a non-significant failure in traction at all doses tested. Conclusions: These findings indicate that the extract in higher doses has exerts a weak sedative and non-effect about the motor coordination. The results obtained in the preliminary phytochemical testing thus suggest that the ethanolic leaf extract of E. clarensis contains some metabolites, which may be responsible of sedative action.

Current State of Research on Bio-Source Composite

This paper is a review of the current research on bio-source composite and especially flax fibers reinforced polymers. Fabrication methods and fiber treatments are presented.The mechanical properties found in the scientific literature are discussed.Experimental results from traction tests are presented for a bio-source composite: epoxy resin reinforced with flax fibers.

Development of a High-Power Two-Roller Traction Tester and Measurement of Traction Curves

Development of a High-Power Two-Roller Traction Tester and Measurement of Traction Curves

Stop Blaming the Septum.

To identify if isolated surgical violation of the orbital septum predisposes to "middle lamellar" scarring and subsequent postblepharoplasty lower eyelid retraction. A retrospective review of patients who underwent transconjunctival blepharoplasty in either a postseptal (orbital septum undisturbed) or preseptal (septal incision required) plane was performed. Patients undergoing skin excision, orbicularis muscle plication, and canthal suspension were excluded. The presence of clinically apparent postoperative lower eyelid retraction and limitation of forced superior eyelid excursion (forced traction testing) were assessed. Two hundred eighty-eight patients (576 eyelids) were evaluated. One hundred fifty-eight patients (316 eyelids, 55%) had transconjunctival blepharoplasty performed in a postseptal plane and 130 patients (260 eyelids, 45%) in a preseptal plane. Two hundred two patients (404 eyelids, 70%) had forced traction testing performed postoperatively. After surgery, there were no patient complaints of change in lower eyelid position, subjective physician assessment of clinically apparent lower eyelid retraction, and only 1 case (0.5%) of a positive forced traction test in a patient with conjunctival scarring after significant postoperative infection. Lower eyelid scars leading to eyelid retraction after blepharoplasty are not likely related to "isolated" orbital septal scars (middle lamellar scars). Their designation as a "multilamellar scar" is more appropriate.

Real-Time Multi-Rate Predictive Cascade Speed Control of Synchronous Machines in Automotive Electrical Traction Drives

A challenging task in automotive electrical traction drives is to control the speed of synchronous machines due to the existing physical and computational constraints. The goal of this paper is to find a control solution which can answer this problem. To this end, a multirate predictive cascade speed control structure suitable for real-time implementation is proposed. The focus in this paper is only on the design of the outer-loop controller. First, a suitable mathematical model for the outer-loop plant which includes also the dynamics of the inner control loop is obtained. Second, a one-step-ahead state-feedback model predictive controller based on flexible Lyapunov function concept is employed to control the rotor electrical speed. Third, a state and disturbance observer is employed to estimate the load torque and the unmeasured state. This ensures also offset-free operation of the closed-loop system. To illustrate its effectiveness, the proposed control solution is implemented in a real microcontroller and tested in real time on an industrial hardware-in-the-loop test bench and on a real traction test bench.

English

Sonchus arvensis, a perennial sowthistle, is a common but underutilized species of Kathmandu, Nepal. Several uses like sedative, antioxidant and kidney stone eradicating properties have been identified till date, but study on other pharmacological activities is not yet explored. Therefore, this plant was collected from Kathmandu; aerial parts of the plant were dried, crushed, and extracted using a Soxhlet apparatus. The methanolic extract was then concentrated for screening pharmacological effects. While comparing with the standards, the plant was found to possess strong anti-inflammatory activity and inhibitory effect in Gastro Intestinal (GI) motility and locomotor activity in a dose-dependent fashion. The plant, however, did not show skeletal muscle relaxant activity as observed in the traction test and inclined plane test. Thus, it is concluded that the plant possess strong phyto-chemicals having anti-inflammatory activity and inhibitory effect in locomotion and GI motility. &nbsp; Key words: Sonchus, anti-inflammatory, motility, locomotion, extraction.

Hydrogen sulfide improves neural function in rats following cardiopulmonary resuscitation.

The alleviation of brain injury is a key issue following cardiopulmonary resuscitation (CPR). Hydrogen sulfide (H2S) is hypothesized to be involved in the pathophysiological process of ischemia-reperfusion injury, and exerts a protective effect on neurons. The aim of the present study was to investigate the effects of H2S on neural functions following cardiac arrest (CA) in rats. A total of 60 rats were allocated at random into three groups. CA was induced to establish the model and CPR was performed after 6 min. Subsequently, sodium hydrosulfide (NaHS), hydroxylamine or saline was administered to the rats. Serum levels of H2S, neuron-specific enolase (NSE) and S100β were determined following CPR. In addition, neurological deficit scoring (NDS), the beam walking test (BWT), prehensile traction test and Morris water maze experiment were conducted. Neuronal apoptosis rates were detected in the hippocampal region following sacrifice. After CPR, as the H2S levels increased or decreased, the serum NSE and S100β concentrations decreased or increased, respectively (P<0.0w. The NDS results of the NaHS group were improved compared with those of the hydroxylamine group at 24 h after CPR (P<0.05). In the Morris water maze experiment, BWT and prehensile traction test the animals in the NaHS group performed best and rats in the hydroxylamine group performed worst. At day 7, the apoptotic index and the expression of caspase-3 were reduced in the hippocampal CA1 region, while the expression of Bcl-2 increased in the NaHS group; and results of the hydroxylamine group were in contrast. Therefore, the results of the present study indicate that H2S is able to improve neural function in rats following CPR.

English

Continued research on traditional herbal drugs has become important than ever due to their increasing use and demand as food supplements and nutraceuticals. The standardized extract of Centella asiatia (L.) Urban (Apiaceae), commonly known as Gotu kola, was evaluated for neuropharmacological, analgesic and anti-inflammatory effects. Neuropharmacological activities were performed on specifically design apparatus, whereas anti-inflammatory test was carried out by 2% formalin in right hind paw of mice and analgesic effect was observed by 1% acetic acid induced writhing test. During central nervous system (CNS) activities (open field, cage cross, head dip, rearing, traction, light and dark test), the extract exhibited marked CNS depressive effect at 300 mg/kg dose. The results were compared with reference drug diazepam 2 mg/kg. C. asiatica extract (300 mg/kg) produced significant anti-inflammatory response in 2nd phase of formalin induced inflammation (61.12%; p ≤ 0.05). It also reduced no. of writhes up to 40.10% (500 mg/kg). Our findings support the respective traditional use of C. asiatica to treat painful and inflammatory conditions along with its supportive sedative and CNS depressant and muscle relaxant effect. Key words: Centella asiatica, CNS depressant, sedative, anti-inflammatory.

Influence of temporary cement in the tensile strenght of full crowns cemented with resin cement

This study evaluated the influence of residual eugenol on the tensile strength in the ceromer crowns cementation, using resin cement. Thirty-nine third molars were prepared for a full crown. For each prepared tooth one provisional and one ceromer crown were made. The teeth were divided into three groups according the temporary cement (n=13): GTB: Temp Bond; GTBNE: Temp Bond NE and GDY: Dycal. After temporary cementation, the teeth were kept in distilled water for one week and then submitted to traction test in a universal testing machine (EMIC DL 500), using a 200Kgf load cell at 0.5mm/min speed. After the test, the teeth were cleaned and received the final adhesive cementation of ceromer crowns. Next, the specimens were kept in distilled water (370C) for a week and then the traction test was performed, also at 0,5mm/min. The comparison among groups was carried out by variance analysis (ANOVA) followed by the Tukey test (p?0.05). The results (Kgf) of provisional cementation for groups GTB, GTBNE and GDY were respectively: 2.75 ± 1.35b, 3.43 ± 1.66ab, and 4.48 ± 1.11a. The results of the adhesive cementation (Kgf) were respectively: 42.71 ± 15.33b, 57.59 ± 15.66a, and 54.75 ± 15.28ab. It was concluded that the temporary cement containing eugenol shows negative influence on the removal resistance of crowns cemented with resin cement.

Geopolymer/PEG Hybrid Materials Synthesis and Investigation of the Polymer Influence on Microstructure and Mechanical Behavior

Geopolymers are aluminosilicate inorganic polymers, obtained from the alkali activation of powders containing SiO2+Al2O3>80wt%, mainly proposed as environmentally friendly building materials. In this work, metakaolin-based geopolymers have been prepared and a water-soluble polymer, polyethylene glycol (PEG), has been added in different percentages to obtain organic-inorganic hybrid geopolymers. The influence of both the polymer amount and aging time on the structure and the mechanical behavior of the materials were investigated. FTIR spectroscopy allowed us to follow the evolution of the aluminosilicate framework during the geopolymerization process. This analysis revealed that PEG leads to a network which is rich in Al-O-Si bonds and forms H-bonds with the inorganic phase. SEM microscope showed that the two phases are interpenetrated on micrometric scales. Traction and bending tests have been carried out on appropriate samples to investigate the mechanical behavior of the obtained hybrids, showing that both PEG content and aging time affect the material behavior.