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This review identifies the three-dimensional knee loads that have the highest risk of injuring the anterior cruciate ligament (ACL) in the athlete. It is the combination of the muscular resistance to a large knee flexion moment, an external reaction force generating knee compression, an internal tibial torque, and a knee abduction moment during a single-leg athletic manoeuvre such as landing from a jump, abruptly changing direction, or rapidly decelerating that results in the greatest ACL loads. While there is consensus that an anterior tibial shear force is the primary ACL loading mechanism, controversy exists regarding the secondary order of importance of transverse-plane and frontal-plane loading in ACL injury scenarios. Large knee compression forces combined with a posteriorly and inferiorly sloped tibial plateau, especially the lateral plateau-an important ACL injury risk factor-causes anterior tibial translation and internal tibial rotation, which increases ACL loading. Furthermore, while the ACL can fail under a single supramaximal loading cycle, recent evidence shows that it can also fail following repeated submaximal loading cycles due to microdamage accumulating in the ligament with each cycle. This challenges the existing dogma that non-contact ACL injuries are predominantly due to a single manoeuvre that catastrophically overloads the ACL.

Comprehensive experiments including monotonic tension and monotonic compression of specimens taken from a rolled AZ31B Mg thick plate along five different material orientations with respect to the rolled direction (RD), and free-end torsion of a tubular specimen machined along the thickness direction (ND) were conducted. The experimental results were used to evaluate an elastic-viscoplastic self-consistent model with the consideration of twinning and detwinning (EVPSC-TDT) on magnesium (Mg) alloys. The EVPSC-TDT model provides stress-strain curves and the hardening rates in close agreement with the experimental results of all the 11 loading cases. The model adequately predicts the textures after fracture of all the 11 loading cases and the evolutions of tension twins with increasing strains for tension in the ND, compression in the RD, and torsion along the ND. The Swift effect was observed in the experiment and was properly simulated by the model.

Welded hollow spherical joints are commonly used in reticulated shell structures. Corrosion on the surface of the joints can significantly reduce their compression capacity. Pitting corrosion is a typical corrosion type on steel structures. A corrosion pit forms at random locations and has a random size. Its random size is indicated by random planar size and thickness – that is, multiple-random pitting corrosion. In this work, a series of non-linear numerical analyses was conducted to investigate the influences of these parameters on the mass loss and compression capacity of welded hollow spherical joints. The aim of this work was to construct a probabilistic distribution model of the compression capacity of the joints with multiple-random pitting corrosion and establish the relationship of the probabilistic distribution model with the specified corrosion and geometric parameters. The work also provided a method for determining the probabilistic model of the joints under actual conditions. This work could serve as a basis for the stochastic analysis of integral structures connected by welded hollow spherical joints with random pitting corrosion.

Vertebral compression fractures (VCF) are frequent injuries mostly related to bone fragility[1][1] and are successfully treated by cementoplasty, such as vertebroplasty or kyphoplasty.[2 3][2] Vertebroplasty requires the use of two-dimensional (2D) imaging for intraoperative control of cement

The research examines the outcomes of shear and flexure testing on reinforced concrete beams made from steel and polypropylene fibre. As well as assessing the impact of fibre in this structural integrity with shear strengthening ratios, certain elements in the characteristics of the cement that is both new and hardened are presented. 14 square beams being put into practice. Tests were made. There were beams produced from 7 distinct mixing dimensions, depending on the kind and the fibre content. For each composite mix there were two beams: one with and the other without stirrups. The primary changes caused by the introduction of fibres were enhanced shear strength, rigidity (especially after the first breaking stage) and ductility. The characteristics of hard concrete (tensile strength, compressive strength and elasticity modules), longitudinal reinforcement concrete, stresses in stirrups, were other factors utilized for the analysis of performance (at the compression and web zone).

This retrospective case series aimed to identify whether trans-articular screws, dorsal bridging plates or if a 4-corner compression plate offers better functional outcome after B2 Lis Franc injuries. Thirty-eight patients underwent surgical fixation for these injuries over five years in a Level 1 Trauma Centre. Patients were treated in 1 of 3 treatment arms: trans-articular screw, dorsal bridge plate, or 4-corner compression plate fixation. The primary outcome measures were the Manchester Oxford Foot and Ankle Questionnaire and the Euroqol- 5DL score and surgical results included postoperative complications and further surgery. Injury type, energy of mechanism, open versus closed status were not significantly different within any fixation group. We achieved 94.7% (n=36) good anatomical reduction. Finding significant improvement between plate fixation (both types) versus trans-articular screw groups treatment functional outcomes. A clinically crucial improvement in Manchester Oxford Foot & Ankle Questionnaire scores, and improved Euroqol- 5DL outcomes between 4-corner compression plate and trans-articular screw group. Overall, there was no significant difference in metalware failure, metalware removal and soft tissue complications. This study concludes that functional outcomes after Lis Franc fractures are not just dependant on the quality of anatomical reduction but are affected by fixation type. Further studies are required to provide qualitative analysis and assessment of dorsal bridge plate fixation versus 4-corner compression plate. Significantly, we have seen the 4-corner compression plate group reached the minimum clinically meaningful difference in the Manchester Oxford Foot and Ankle Questionnaire when compared to trans-articular screw fixation. Level of Clinical Evidence: 4

Twinning-detwinning (TDT) behavior in a strongly basal-textured Mg-Li alloy during two-step compression (RD)-compression (ND) process was investigated using quasi-in-situ EBSD. TDT behavior and TDT variants selection were statistically discussed with the loading path for the first time. Non-Schmid twinning behavior was observed in the first step compression, owing to the local stress fluctuations by neighboring twins; in contrast, Schmid's law well predicted the detwinning variants selection. This asymmetrical TDT behavior was first investigated to date related with the strong basal texture and loading path. Besides, with the progress of compression, Schmid factors for twinning demonstrated a decreasing tendency; however, those for detwinning during the second step displayed an abnormally increasing trend, fundamentally stemming from prior twinning behavior.

The structural behaviour of concrete-filled steel tubular columns subjected to full and local compression loads was investigated. Experiments were performed on 18 columns with different cross-sectional slenderness ratios. The experimental parameters were the local compression area ratio and the slenderness ratio. The strength index, stiffness and ductility index of the columns were obtained through experimental tests. The results revealed that the local compression area ratio and slenderness ratio are key parameters that considerably affect the strength capacity of columns subjected to full and local compression loads. Design models provided in various international codes and various studies were used to validate the experimental results. Furthermore, the suitability of these design models for predicting the strength capacity of columns subjected to full and local compression loads was examined. Finally, through regression analysis, a simplified design model was developed for predicting the strength capacity of columns under full and local compression loads.

The strain characteristic and load transmission of mixed granular matter are different from those of homogeneous granular matter. Cyclic loading renders the mechanical behaviours of mixed granular matter more complex. To investigate the dynamic responses of gravel–sand mixtures, the discrete element method (DEM) was used to simulate the cyclic loading of gravel–sand mixtures with low fines contents. Macroscopically, the evolution of the axial strain and volumetric strain was investigated. Mesoscopically, the coordination number and contact force anisotropy were studied, and the evolution of strong and weak contacts was explored from two dimensions of loading time and local space. The simulation results show that increasing fines content can accelerate the development of the axial strain and volumetric strain but has little effect on the evolution of contact forces. Strong contacts tend to develop along the loading boundary, presenting the spatial difference. Weak contacts are firstly controlled by confining pressure and then controlled by axial stress, while strong contacts are mainly controlled by axial stress throughout the whole cyclic loading. Once compression failure occurs, the release of axial stress causes the reduction of strong contact proportion in all local regions. These findings are helpful to understand the dynamic responses of gravel–sand mixtures, especially in deformation behaviours and the Spatio-temporal evolution of contact forces.

Investigating the damage and ignition behaviors of polymer-bonded explosive (PBX) under a coupled impact and high-temperature loading condition is required for the safe use of charged PBXs. An improved combined microcrack and microvoid model (CMM) was developed for better describing the thermal effects of deformation, damage, and ignition responses of PBXs. The main features of the model under typical dynamic loadings (i.e. uniaxial tension and compression, and lateral confinement) at different initial temperature were first studied. And then the effects of temperature on impact-shear sensitivity of HMX-based PBXs were investigated. The results showed that the ignition threshold velocity of shear-crack hotspots exhibits an increase from 260 to 270 to 315–325 m/s when initial temperature increases from 301 to 348 K; and then the threshold velocity decreases to 290–300 m/s with the initial temperature continually increasing to 378 K. The predicted ignition threshold velocity level of the explosives under coupled impact and high temperature loading conditions were consistent with the experimental data.

YAG (Y3Al5O12) transparent ceramics have attractive application prospects for transparent armor protection modules because of their excellent light transmittance and anti-ballistic capability. Understanding the fracture behavior and damage mechanism of YAG is necessary for armor design. To explore the damage characteristics of YAG under compression and tension, shock compression and shockless spalling experiments with soft recovery technique are conducted. The spall strength of YAG is obtained and the recovered samples are observed by CT and SEM. It is shown that the macroscopic damage characteristic of YAG under compression is vertical split cracks with oblique fine cracks distributed in the entire sample, while that under tension is horizontal transgranular cracks concentrated near the main spall surface. The cracks generated by macroscopic compression, tension and shear stress extend in similar tensile form at the microscale. The proportion of transgranular fractures on spall surfaces is higher than that of cracks induced by macroscopic compression. Meanwhile, higher loading rate and longer loading duration increase the transgranular fracture percentage.

The compression behavior of the lattice-walled tubes under variable strain rates are investigated by numerical simulation, and the stress-strain relationship of the structure under quasi-static loading is theoretically analyzed. The finite element software LS-DYNA is used to simulate the structure established by the beam element, and the critical impact velocity is obtained when the structure collapses layer by layer. According to the plastic hinge theory and considering the combined action of the beam's bending moment and axial force in the structure, the stress-strain relationship of the structure under quasi-static loading is derived and compared with the experimental results. The numerical simulation results reveal that the structure of the single-layer gradient tube(SGC) does not undergo shear deformation under quasi-static and low-speed impact. The critical speed of the gradient square tube(GS) is higher than that of a cylindrical tube. The theoretical model can correctly reflect the mechanical response of the structure under uniaxial compression.

Deep and high-stress mining results in stress transfers onto the previously placed backfill, and mines have recorded several MPa induced backfill stress. Understanding the backfill-rock mass interaction is therefore critical. Previous work considered tabular ore bodies undergoing primarily one-dimensional compression and showed how the backfill reaction curves could be estimated from oedometer laboratory test results. This work considers massive orebodies and develops a similar approach based on isotropic compression curves. Isotropic compression tests exceeding 6 MPa are carried out on samples with 3.0–11.1% binder content, tested at 1-day cure time to 28-day cure time. The compression curve is characterized in three stages: initial elastic compression up to a yield point, followed by a transition stage to the start of a final stage with a linear post-yield compression line in \({\epsilon }_{v}-\text{l}\text{o}\text{g}\left({p}^{\text{'}}\right)\) space. Because these isotropic compression tests are rare (the reported results are the first for Cemented Paste Backfill), attempts are made to relate the isotropic compression test parameters to parameters from the more commonly used Unconfined Compression Strength (UCS) tests. Unifying equations as functions of binder content and cure time are found to determine the initial yield stress and the peak strength from UCS tests. These are then related to the corresponding parameters in isotropic compression. Finally, the slope of the post-yield compression line is found as a function of UCS, thereby enabling complete reconstruction of the isotropic compression response based on parameters from carefully controlled UCS tests, as functions of binder content and cure time. Although the calibrated parameters are specific to the studied mine’s materials, the framework is general and applicable to other mines’ CPBs.

The texture profile analysis test is an imitative test to determine texture properties of food, which quantify the consumer’s perception of eating food. The instrumental texture parameters obtained from this test depend on the specimen size and the nonstandardized test conditions. To overcome this problem, texture properties are here related to intrinsic mechanical properties, which are independent of the test conditions. Two types of materials are used to investigate the effect of viscoelasticity, plasticity and damage on the texture parameters for varying test conditions. Analytical relations between mechanical properties, test conditions, and the instrumental hardness, springiness, cohesiveness, and adhesiveness are determined. The hardness is obtained from the stiffness of the material, which is potentially rate-dependent, and the yield stress of a material in case of plasticity. The springiness is determined by the recoverable or irrecoverable strain in the material, which results from the mechanical properties in combination with the test conditions. Cohesiveness and springiness are found to be strongly related, unless structural damage is present in the material. Adhesiveness is only an indirect measure of the adhesion between the material and compression plate and depends on the test conditions and stiffness of the material. Finite element simulations reveal a decrease of hardness in case of a nonflat top surface, indicating the importance of geometrical effects.

Preforming process would change yarn angle and yarn orientation, its influence on the material properties and material orientations needs to be considered in the performance analysis. However, most current performance models fail to account for the preforming effect. An integrated performance model accounting for the impact of preforming has been developed in this research. In this integrated model, part geometry, yarn angle and orientation after preforming of multiple prepreg layers are predicted by Finite Element Analysis (FEA) using a non-orthogonal constitutive law. Experiments were conducted to validate the preforming simulation for a single dome composites structure made by two prepreg layers with different initial fiber orientations. Performance analysis until failure was then conducted for the single dome structure to validate the integrated performance model. Comparison between simulation and experiment shows that not only the failure mode and failure zone, but also the force-displacement curve during compression process are captured correctly by the performance model, demonstrating the effectiveness of the newly proposed model in accounting for the impact of preforming process.

The release and dissolution of an active pharmaceutical ingredient (API) from the solid oral formulation into the gastrointestinal (GI) tract is critical for the drug's absorption into systemic circulation. Extended-release (ER) solid oral dosage forms are normally subjected to physical shear and grinding forces as well as pressure exerted by peristaltic movements when passing through the GI tract. The complex physical contraction and sample friction exerted by the GI tract are not simulated well by compendial dissolution methods. These limitations render traditional in vitro dissolution testing unable to discriminate and predict a product's in vivo performance. The objective of this study was to develop a dissolution method that better simulates the GI environment that products are subject to when taken by patients. A newly designed Mechanical Apparatus under GI Conditions (MAGIC) was assembled with a dissolution platform and mechanical capabilities to allow in vitro dissolution testing under sample contractions and friction. The dissolution platform, with medium flow-through configuration, was manufactured by 3D printing. A 60 mg polymer matrix-based ER nifedipine product was tested. To simulate GI physiological conditions during the dissolution testing, the flow rate of the medium, and a combination of mechanical compression with rotation induced sample friction at various rotation frequencies were explored. The polymer matrix-based nifedipine ER formulation used here failed its controlled release functionality in the simulated GI environment under mechanical compression and sample friction. The results showed that the MAGIC system, with flow-through configuration under compression and sample friction, has advantages over compendial methods in testing ER solid oral formulations.

Background Giant aneurysms of the intracranial vertebral artery are very rare cerebrovascular lesions. Due to the rarity of these aneurysms, we know little about them. Methods We performed a systematic review of the English literature by searching the PubMed database. The inclusion criteria were as follows: (a) the full text was available and (b) complete clinical data were available. Results A total of 45 articles were identified, containing 53 patients (53 aneurysms). The patients were aged from 5 to 77 years (48.8 ± 20.8 years). Four patients receiving conservative treatment died. The remaining 49 patients were divided into the aneurysm removal group ( n = 17) and the aneurysm reserve group ( n = 32). The outcomes of the 49 treated cases could be obtained in 45 cases, 31 of which (68.9%, 31/45) had a Glasgow outcome scale score of 4–5. Conclusions It is still difficult to treat intracranial giant vertebral artery aneurysms, regardless of the treatment selected. Because of the malignant natural history, aggressive treatment is still advocated.

Pressure therapy is widely used in the management of keloid mass and for preventing postexcision recurrence of earlobe keloid. Although various types of compression devices are available, the pressure applied by these devices is uncontrolled and associated with the risk of pressure necrosis. This article presents a novel design for a compression device with threaded connectors to control the amount and direction of the pressure applied on the keloid mass.

Background Focusing on compression fractures of bone by finite elements, we evaluated bone strength based on the computed tomography-based finite element method. However, the exposure dose is an issue. We aimed to investigate the quantity of reduction of the radiation dose with respect to the reference dose by comparing the calculation results of compression fractures of the vertebral body using experimental data obtained from the spine of a pig. Methods Computed tomography images of a self-made phantom that enclosed the lower lumbar vertebra of edible wild pigs were obtained under baseline-dose conditions using various lower tube currents. Images obtained under reference-dose conditions were reconstructed using the filtered back-projection method, whereas images obtained under low-dose conditions were reconstructed using both the filtered back-projection method and the iterative reconstruction method. Computer simulations involving the creation of finite element models using all images were implemented for the compression load calculation for vertebral body parts. Based on the calculated results, images of the low-dose and reference-dose conditions were compared. Results Using pigs’ lower lumbar vertebrae, finite element model analysis of low-dose X-ray computed tomography images showed that equivalent results can be obtained with a dose of approximately 40% of the standard radiographic reference doses. As for the compression stress intensity, the same results as those under reference-dose conditions were obtained using the iterative reconstruction method in combination with computed tomography-based finite element method. Conclusions The combination of the iterative reconstruction method with the computed tomography-based finite element method is an effective image reconstruction method for achieving dose reduction.

To study the hot deformation behavior of Mg–8.3Gd–4.4Y–1.5Zn–0.8Mn (wt%) alloy, hot compression tests were conducted using a Gleeble–3500 thermal simulator at temperatures ranging from 653 to 773 K, true strain rates of 0.001–1 s−1, and a deformation degree of 60%. Results of hot compression experiments show that the flow stress of the alloy increases with the strain rate. The true stress–true strain curves are corrected by correcting the effect of temperature rise in the deformation process. Activation energy, Q, equal to 287380 J/mol and material constant, n, equal to 4.59 were calculated by fitting the true stress–true strain curves. Then, the constitutive equation was established and verified via finite element simulation. Results of the hot processing map show that the probability of material instability increases with the degree of deformation, which indicates that the material is not suitable for large deformation in a single pass. On the whole, the alloy is appropriate for multipass processing with small deformation and a suitable processing temperature and strain rate are 733 K and 0.01 s−1, respectively.

The effect of contact pressure on the performance of electrolyte supported planar solid oxide fuel cells (SOFCs) are experimentally investigated in this study by varying the pressure applied on the push rod. For this purpose, cells with 1 cm2, 9 cm2, 16 cm2, 81 cm2 and 150 cm2 active areas are manufactured and tested under different external compression pressures. Maximum power densities of 0.486 W/cm2, 0.308 W/cm2 and 0.231 W/cm2 are obtained from the cells with an active area of 1 cm2, 9 cm2 and 16 cm2, respectively, under the same contact pressure. When the impedance results are considered, it is seen that under the same compression pressure, the cell resistance increases nonlinearly with the cell size. However, when the pressure is adjusted according to the active area, a similar power density of approximately 0.4 W/cm2 is obtained from these three cells. Moreover, very similar performances are measured from all cells when a portion of cells with 1 cm2 active is cut and tested under the same contact pressure of 0.2 MPa. The overall results indicate that the external load should be adjusted according to the cell size, but there is no linear relationship between the active area and the applied external pressure.

BACKGROUND: Some recovery strategies are needed to reduce or eliminate the effect of negative symptoms caused by exercise. OBJECTIVE: The aim of this study was to determine the effect of different types of recovery after single-bout strength exercises on biomarkers of muscle damage, cytokine release and lactate elimination. METHODS: Following familiarization, 10 male volunteers performed four randomized recovery protocols (passive or active recovery with or without compression garments) following a single bout of resistance exercise (squat and deadlift exercises). The blood creatine kinase (CK), lactate dehydrogenase (LDH), interleukine-6 (IL-6), and tumor necrosis factor-alfa (TNF-α) values were measured before and after exercise, and after 24, 48, 72 hours. RESULTS: The CK analysis showed that all protocols significantly increased (p< 0.05) CK activity compared to the pre and 24 h post time points. Interestingly, protocol 3 and 4 significantly decreased (p< 0.05) CK activity compared 24 and 72 h post-exercise. LDH, IL-6, and TNF values did not show significant difference (p> 0.05) at the time points tested. CONCLUSIONS: Active recovery is an effective method for reducing the severity and duration of muscle damage and for accelerating the clearance of blood lactate (BLa) following a single bout of strength training. There is no added benefit of using compression garments.

The demand for a load distributive compression anchor (LDCA) in construction sites has been increasing, owing to its high bearing capacity and removable steel strands. As an LDCA comprises multiple anchor bodies and unbonded steel strands, the load applied to the strands generates a distributive compressive stress in the grout, preventing high concentration of grout–ground shear stress. Unlike in the conventional anchors, in an LDCA, independent load transfer of each anchor body induces interference effect between adjacent anchor bodies. Therefore, for an efficient design of an LDCA, it is necessary to investigate the load transfer mechanism considering the effect of multiple anchor bodies. In this study, a series of anchor pull-out field tests was conducted for LDCAs consisting of a single anchor body, and double and triple anchor bodies spaced by 1, 2, and 3 m. According to the test results, the LDCA showed a stiffer load–displacement behavior with an increase in the number and spacing of the anchor bodies. The multiple anchor bodies of the LDCA generated an overlapping of the grout axial load and induced its rapid dissipation, increasing the grout–ground shear stress. This interference effect was more clearly observed with a decrease in the anchor body spacing.

The twinning behavior, dynamic recrystallization (DRX) mechanism and the resultant texture evolution of the extruded Mg-xBi (x=0.5 wt.%, 2.0 wt.%) alloys were systematically investigated during hot compression at the strain rate of 10 s−1 and temperature of 200°C. The results indicate that the types and intensities of the texture are greatly dependent on the twining behavior and DRX mechanism. At the initial stage, the evolution of texture is mainly domination by the formation and variation of { 10 1 ¯ 2 } extension twins, which is beneficial to the compression direction (CD) -tilted basal texture. With an increase in the strain, the texture evolution is more greatly regulated by the DRX mechanism. Besides, the pyramidal slip and basal slip are activated during the compression process, resulting in the Schmid factors (SF) of pyramidal slip remain at ∼0.4 and the average SFs for basal slip increase from 0.2 to 0.34 as the strain increase. These findings provide a new insight into controlling the texture of wrought Mg-Bi-based alloys during hot deformation processing.

A diagnosis of lymphedema comes with a lifetime requirement for careful self-care and treatment to control skin deterioration and the consequences of excessive fluid and protein buildup leading to abnormal limb volume and an increased risk of infection. The burden of care and psychosocial aspects of physical disfiguration and loss of function are associated with compromised quality of life (QoL). The current standard therapeutic intervention is complex decongestive therapy with manual lymph drainage and frequent wearing of compression garments. With insurance limitations on therapy visits and the time and travel required, additional home treatment options are needed. Pneumatic compression pumps that mimic the manual massage pressure and pattern are sometimes prescribed, but these are bulky, difficult to apply, and require immobility during treatment. An open-label pilot study in 40 subjects was performed to evaluate the QoL and limb volume maintenance efficacy of a novel wearable compression system (Dayspring™) that is low profile, easy to use, and allows for mobility during treatment. After 28 days of use, subjects had a statistically significant 18% (

For estimating the long-term stability of underground framework, it is vital to learn the mechanical and rheological characteristics of rock in multiple water saturation conditions. However, the majority of previous studies explored the rheological properties of rock in air-dried and water saturated conditions, as well as the water effects on compressive and tensile strengths. In this study, andesite was subjected to direct shear tests under five water saturation conditions, which were controlled by varying the wetting and drying time. The tests were conducted at alternating displacement rates under three vertical stresses. The results reveal that the shear strength decreases exponentially as water saturation increases, and that the increase in shear strength with a tenfold increase in displacement rate is nearly constant for each of the vertical stresses. Based on the findings of the shear tests in this study and the compression and tension tests in previous studies, the influences of both water saturation and loading rate on the Hoek-Brown failure criterion for the andesite was examined. These results indicate that the brittleness index of the andesite, which is defined as the ratio of uniaxial compressive strength to tensile strength, is independent of both water saturation and loading rate and that the influences of the water saturation dependence and the loading rate dependence of the failure criterion can be converted between each other.

Janus particles (JPs) and surfactants express different behaviors at the oil-water interface under compression. When both are present at the interface, their synergies result in a different collapse mechanism than when present individually depending on the concentration of the JPs and surfactants.Coarse-grained modeling methods were used to probe the synergies between Janus nanoparticles and nonionic surfactants on the stability of an oil-water interface under compression. When both JPs and surfactants were present, the interface was covered at 0-55% area by JPs and contained surfactants at 0-40% of the interfacial surfactant concentration corresponding to the critical micelle concentration (CMC).Compression of the interface with only surfactants resulted in the expulsion of surfactant molecules to the water phase once the interfacial concentration of surfactant molecules reached the CMC value. Compression of a Janus particle-laden interface past the closed-packing point led to a buckled interface, so that the total interfacial area remained constant upon further compression. When both surfactants and JPs were present on the interface, JPs still caused buckling, which helped retain the surfactant molecules on the interface. The interface exhibited a higher level of deformation in presence of surfactants. When the surfactant concentration was high, under compression, the surfactants partitioned into the water phase, but the buckling of the interface persisted.

An interaction function was constructed based on the axial compression/tension and shear loads of orthotropic plates. The coefficients of the polynomial function were determined by uniaxial test results. Buckling interaction and failure interaction formulae under combined axial tension/compression and shear loads were established. Based on the uniaxial load test results of orthotropic plates, the buckling load and bearing capacity under any proportion of the combined loads could be predicted by using the proposed interaction formulae. The buckling interaction curves and failure envelopes predicted by the proposed interaction formulae were in excellent agreement with the test results.

The use of fibre-reinforced polymers (FRPs) as internal confining reinforcement in combination with longitudinal steel bars in concrete compression members provides significantly improved strength, ductility and durability. To date, only a few experimental studies have been carried out to establish the compressive behaviour of concrete columns longitudinally reinforced with steel bars and confined with FRP ties. This paper provides a confinement model with several expressions for predicting the axial stress–strain response of hybrid-reinforced (i.e. longitudinal steel bars combined with FRP ties) square concrete columns under axial compression loading. The model considers the influences of several test parameters, such as the configuration, size, volumetric ratio, spacing and type of ties (FRP pultruded bar ties and closed-type wound rectangular-section ties). The proposed model predicted well the peak and ultimate strength and strains compared with existing models. The overall accuracy of the model was also assessed against selected test stress–strain responses.

External aortic compression has been investigated as a treatment for non-compressible truncal haemorrhage in trauma patients. We sought to systematically gather and tabulate the available evidence around external aortic compression. We were specifically interested in its ability to achieve hemostasis and aid in resuscitation of traumatic arrest and severe shock and to consider physiological changes and adverse effects. A scoping review approach was chosen due to the highly variable existing literature. We were guided by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses, using the specific extension for scoping reviews. Searches were done on PubMed and Scopus databases in October 2020. We found that a range of studies have investigated external aortic compression in a variety of settings, including case reports and small case series, porcine hemorrhage models and effects on healthy volunteers. External aortic compression for postpartum hemorrhage in a single center provided some evidence of effectiveness. Overall the level of evidence is limited, however, external aortic compression does appear able to achieve cessation of distal blood flow. Furthermore, it appears to improve many relevant physiological parameters in the setting of hypovolemic shock. Application for more than 60 minutes appears to cause increasingly problematic complications. In conclusion we find that the role of external aortic compression warrants further research. The intervention may have a role as a bridge to definitive treatment of noncompressible truncal haemorrahge.

OBJECTIVE For same-day discharge lower extremity arterial disease (LEAD) endovascular procedures, femoral manual compression could be an alternative to arterial closure devices. The aim of this study was to assess the security and efficacy of same-day discharge after manual compression in patients treated for LEAD endovascular revascularization with 5F sheath. METHODS FREEDOM OP was a national multicenter, prospective, single arm study. Patients with symptomatic LEAD (Rutherford 2 to 5) and eligible for same-day discharge were included. The primary endpoint was the total in-hospital admission rate, which includes overnight surveillance and rehospitalization rate at 1 month. RESULTS Between September 2017 and August 2019, 114 patients were included. The mean age of the patients was 66 ± 10 years and most of them were claudicant (103; 94%). Mainly femoropopliteal lesions were treated (178; 70%) and the technical success was 97%. One hundred forty two 5F stents and fifty one 5F drug coated balloon were delivered. The mean manual compression duration was 13 ± 4 min. Major access-related complications rate was 4.5%. Total in-hospital admission rate was 11%. Seven patients had overnight surveillance and 5 were rehospitalized (2 for the target lesion). No rehospitalisation was carried out within 24 hours after discharge. No major cardiovascular event, including death, was observed. The patients were significantly improved in term of clinical status (p

The increase in solid fraction (SF) of a packed granule bed with pressure applied during the in-die compression process results in an evolution of the tablet's matrix and mechanical strength. In this case study, the tensile strength (TS) of a dry granulated microcrystalline cellulose (MCC)/mannitol (MNT)-based formulation was modeled in light of the deformation potential, ∆ (tablet SF – initial granule bed SF). Results showed that the TS of tablets linearly decreased as SF of granules (produced as mini-tablets of an ibuprofen formulation) increased. The formulated granules achieved a measurable tablet strength at a slightly lower critical deformation potential (∆c) than the pure MCC granules. Beyond ∆c, tablet TS increased almost linearly as the deformation potential increased, and the rate was higher for tablets with higher SF. Compared to the simple MCC system, the granules of the MCC/MNT-based formulation were weaker, and TS of tablets increased with deformation potential at a lower rate.

The use of nanoparticles in fuels provides new opportunities for modification of fuel properties, which may affect the operational parameters of engines, in particular the efficiency and fuel consumption. The paper presents comparison of compression ignition engine performance fuelled with neat diesel and nano-diesel. Alumina (Al2O3) was used as nanoparticles. Surface-active substances, including Span 80 surfactant, as well as water admixture were used to improve the stability of the produced fuel. Measurements of the thermal conductivity and dynamic viscosity of the produced mixtures were conducted. In this study was used naturally aspirated, water cooled, four-stroke diesel engine. Addition of Al2O3 nanoparticles result in 4% reduced fuel consumption, addition of TiO2 nanoparticles result in 10% reduced fuel consumption with respect to neat diesel fuel.

This study investigated the effect of fibre reinforcement on the large strain behaviour of compacted clay samples tested using large triaxial test equipment. A novel specimen preparation method was proposed where peds of clay are compacted to closely simulate the in-situ compaction. A large number of 100 × 200 mm triaxial tests and one-dimensional compression tests were performed using reinforced and unreinforced samples. The behaviour of unreinforced samples was observed to be similar to highly fissured clays; ped compaction generated a random fissure pattern due to the contact between peds. The addition of fibres to the compacted samples created fissures with higher mobility at lower friction than those in the unreinforced samples; hence, the state boundary surface of reinforced clay was below that of the unreinforced clay. With the addition of fibres, the failure mechanism changed from the formation of a shear plane to barrelling, demonstrating that the fibres transferred stresses further away from the shear plane, producing a more homogeneous stress distribution. The preparation method proposed here produced a fissure pattern in the clay that introduced transitional behaviour, which was drastically reduced with addition of the fibres, allowing better normalisation and the definition of a unique boundary surface.

A novel yield criterion based on CPB06 considering anisotropic and tension-compression asymmetric behaviors of magnesium alloys was derived and proposed (called M_CPB06). This yield criterion can simultaneously predict the yield stresses and the Lankford ratios at different angles (if any) under uniaxial tension, compression, equal-biaxial and equal-compression conditions. Then, in order to further describe the anisotropic strain-hardening characteristics of magnesium alloy, the proposed M_CPB06 criterion was further evolved to the M_CPB06ev model by expressing the parameters of the M_CPB06 model as functions of the plastic strain. As the model was developed, the stresses and Lankford ratios of AZ31B and ZK61M magnesium alloys at different angles under tensile, compressive and through-thickness compressive conditions were used to calibrate the M_CPB06/M_CPB06ev and the existing CPB06ex2 model. Calibration results reveal that compared with the CPB06ex2 yield criterion with equal quantity of coefficients, the M_CPB06 criterion exhibits certain advancement, and meanwhile the M_CPB06ev model can relatively accurately predict the change of the yield locus with increase of the plastic strain. Finally, the M_CPB06ev model was developed through UMAT in LS-DYNA. Finite element simulations using the subroutine were conducted on the specimens of different angles to the rolling direction under tension and compression. Simulation results were highly consistent with the experimental results, demonstrating a good reliability and accuracy of the developed subroutine.

Flexible polyurethane foam (FPUF) is the most used polyurethane, but the highly flammable characteristic limits its widespread usage. In this work, ZIF-8@Ti3C2Txwas synthesized to reduce the heat and toxic gases of FPUF. Flame-retardant FPUF was characterized by cone calorimeter (Cone), thermogravimetric analysis/fourier-transform infrared spectroscopy (TG-FTIR), tensileand compression tests. Compared with pure FPUF, these results showed that the peak of heat release rate (PHRR), total heat release (THR), CO and HCN of FPUF6 decreased by 46%, 69%, 27% and 43.5%, respectively. Moreover, the tensile and compression strength of FPUF6 demonstrated a 52% and 130% increment, respectively. The superior dual metal catalytical charring-forming effect and physical barrier effect of ZIF-8@Ti3C2Tx were achieved. In summary, a simple and reliable strategy for preparing flame-retardant FPUF with reinforced mechanical and fire safety properties was provided.

A triangular configuration with three parallel cannulated screws is an established treatment for fixing transverse patellar fractures; however, the stability achieved with this approach is slightly lower than that attained with cannulated screws combined with anterior wiring. In the present study, triangular configurations were modified by partially or totally replacing the cannulated screws with headless compression screws (HCSs). Through finite element simulation involving a model of distal femoral, patellar, and proximal tibial fractures, the mechanical stability levels of the modified triangular configurations were compared with that of two cannulated screws combined with anterior wiring. Four triangular screw configurations were developed: three HCSs in a forward and backward triangular configuration, two deep cannulated screws along with one superficial HCS, and two superficial cannulated screws with one deep HCS. Also considered were two parallel cannulated screws (inserted superficially or deeply) combined with anterior wiring. The six approaches were all examined in full knee extension and 45° flexion under physiological loading. The highest stability was obtained with the three HCSs in a backward triangular configuration, as indicated by the least fragment displacement and the smallest fracture gap size. In extension and flexion, this size was smaller than that observed under the use of two deeply placed parallel cannulated screws with anterior wiring by 50.3% (1.53 vs. 0.76 mm) and 43.2% (1.48 vs. 0.84 mm), respectively. Thus, the use of three HCSs in a backward triangular configuration is recommended for the fixation of transverse patellar fractures, especially without the use of anterior wiring.

This paper examines the effect of an external preheating system for an internal combustion engine on fuel consumption, CO2 emissions, and cabin temperature of a Euro4 vehicle. A 1 kW electric system powered by 220 V was installed in series in the cooling system of a vehicle with a compression-ignition engine of 2.5 dm3 capacity. The tests were carried out in simulated urban driving conditions (distance of 4.2 km), extra-urban driving conditions (distance of 17 km), and during idling at cold-start temperatures ranging from -10 oC to 2 oC. Preheating the engine under simulated city conditions reduces fuel consumption by 2.64 dm3/100 km and increases the supply air temperature immediately after engine start-up. Due to the preheater being powered from an external power grid, the cost per trip and total CO2 emissions are increased. Assuming renewable energy sources, CO2 emissions would be reduced the most for the stationary tests after engine preheating. In contrast, emissions would be reduced the least for extra-urban driving.

Ozone (O3) was introduced into the intake air to control the ignition in a gasoline compression ignition (GCI) engine. An early fuel injection at −68 °CA ATDC was adopted to mix the fuel with the reactive O-radicals decomposed from the O3, before the reduction of the O-radicals due to their recombination would take place. The second injection was implemented near top dead center to optimize the profile of the heat release rate. The engine experiments were performed around the indicated mean effective pressure (IMEP) of 0.67 MPa with a primary reference fuel, octane number 90 (PRF90), maintaining the 15% intake oxygen concentration with the EGR. The quantity of the first injection, the second injection timing as well as the ozone concentration were changed as experimental parameters. The results showed that the GCI operation with the ozone addition makes it possible to reduce the maximum pressure rise rate while attaining high thermal efficiency, compared to that without the ozone. Appropriate combinations of the ozone concentration and the first injection quantity achieve low smoke and NOx emissions. Further, the ozone-assisted GCI operation was compared with conventional diesel operation. The results showed that the indicated thermal efficiency of the ozone-assisted GCI combustion is slightly lower than that of the conventional diesel combustion, but that GCI assisted with ozone is highly advantageous to the smoke and NOx emissions.

In this study the effects of thermal shock on the impact damage resistance, damage tolerance and flexural strength of Nextel 610/alumina silicate ceramic matrix composites were experimentally evaluated. Composite laminates with balanced and symmetric layup were gradually heated to 1200°C in an air-based furnace and held for at least 30 min before being removed and immersed in water at room temperature. The laminates were then subjected to low velocity impacts via a hemispherical steel impactor. The resultant damage was characterized non-destructively, following which the laminates were subjected to compression tests. Three-point bend tests were also performed to evaluate the effect of thermal shock on the flexural strength and related failure modes of the laminates. Thermally shocked laminates showed smaller internal damage and larger external damage areas in comparison to their pristine counterparts. For the impact energy and resultant damage size considered, the residual compressive strengths for the thermally shocked and pristine laminates were similar.

ZrC is a promising candidate for the application in ultra-high temperature regime due to its unique combination of excellent properties, such as high melting point, good chemical inertness and high temperature stability. The rapid decrease of strength at high temperatures, however, is one of the obstacles that impedes its practical services. Strengthening of grain boundaries by solute segregation is believed to be an effective way to improve its high temperature performance. Therefore, the segregation tendency of ten solid solute atoms, including Sc, Ti, V, Cr, Y, Nb, Mo, Hf, Ta, W, in ZrC grain boundaries, and the strengthening/weakening effects on grain boundaries due to segregation are investigated by first-principles calculations. The segregation tendency is found dominated by the size effect, which is confirmed by both a qualitative analysis and a quantitative approach based on support vector regression. It means that big atoms tend to segregate to grain boundary sites with local expansions, while small atoms tend to segregate to grain boundary sites with local compressions. Simulations on stress-strain responses indicate that segregation of small atoms (Ti, V, Cr, Nb, Ta, Mo, W) can usually improve grain boundary strengths by inducing compression strains to grain boundaries, even though there is also an exception. In contrast, segregation of Sc and Y will soften grain boundaries. The results reveal that strengthening of grain boundaries by solute segregation is a valuable avenue to enhance high temperature mechanical properties of ZrC, providing guidelines for further design of ZrC based materials.

Background: Cerclage fixation is a known orthopedic technique shown to be beneficial for circumferential augmentation when screw fixation cannot be used or is undesirable. However, ongoing advances in suture materials and knot techniques exist, and there is a paucity of evidence existing which evaluates comparisons between the two. The objective of this study was to investigate the strength and durability of cerclage fixation between the Nice knot suture technique and monofilament wire. Methods: Static displacement over time and compression load testing were analyzed. Compression testing was conducted with the Jamar Hydraulic Hand Dynamometer. Distraction testing was conducted using the Instron test system with its associated program. The Nice knot was tied using number 2 and number 5 FiberWire (Arthrex) and compared to monofilament wire. Clinical failure (displacement of 10 mm), absolute failure (opening of the knot or material failure), maximum compression achieved, and steady state compression maintained were the outcomes of interest. Results: Double-stranded monofilament wire produces maximum consistent compression of 90 kg, followed by single-stranded monofilament wire (60 kg). Number 5 FiberWire has a higher maximum compression load than number 2 FiberWire (50 kg vs. 22 kg), but it is lower than that of the double-stranded monofilament wire constructs. When compared to the single-stranded monofilament construct, the number 5 FiberWire Nice knot is comparable (P < .05). Average steady state compression achieved after 10 minutes of resting showed double-stranded monofilament wire to be 65 kg compared to single- stranded monofilament wire at 42 kg, which when, compared to suture, number 5 FiberWire measured at 15 kg and number 2 FiberWire at 8 kg. Average tension results from Instron distraction testing showed the double-stranded monofilament wire construct was able to withstand greater forces up to a displacement of 6 mm, after which the number 5 FiberWire Nice knot was stiffer. Number 5 FiberWire shows the most linear tension relationship, revealing it more efficiently withstands elastic forces. Load to failure was higher in the number 5 FiberWire Nice knot construct than that in both the monofilament wire constructs. The modes of failure for the Nice knot were always at the knot suture interface rather than at the knot. Conclusion: We propose this suture technique to be a viable alternative method for cerclaging to fix upper limb long-bone fractures.

The increase in demand and introduction of stringent emission regulations resulted in the need to develop and implement innovative technologies towards improving the emission and performance characteristics of compression ignition engines. A hybrid metal matrix composite piston (HMMC) of Al7075 reinforced with 6% of 100 μm Silicon Carbide (SiC) and 4% of 100 μm Aluminium oxide (Al2O3) was fabricated. The HMMC piston was mounted on a compression ignition (CI) four stroke single-cylinder constant speed engine and the test was carried out with eddy current dynamometer attached with computerized data acquisition system. This paper is focused on the study of performance of Al7075-SiC-Alumina composite piston for compression ignition engine application. Experimental investigations were performed at injection pressure of 200 and 220 bar on both standard piston and HMMC piston and analysed the performance, combustion and emission behaviour of CI engine. From the results it was found that the HMMC piston exhibits an improved efficiency and thereby improving the lifetime of the engine. Though a little compromise in performance and emissions has been accepted, the implementation of HMMC pistons will reduce the carbon foot print of running an internal combustion engine.

In this paper we study numerically and experimentally non-reversible deformation of anisotropic, semi-flexible fibre networks. We formulate a Discrete Element Model (DEM) with bonded particles to simulate uniaxial compression of such networks and use this model to describe and quantify the effect of elasto-plastic fibre contacts and fibre-fibre adhesion on non-reversible deformation. Our results show that inter-fibre adhesion plays a role for compression in a low solid volume fraction range where adhesive forces can overcome fibre deformation forces and moments. Also, elasto-plastic contacts between fibres become important at higher solid volume fractions when the yield criterion is exceeded. The combined case of fibres having elasto-plastic contacts and adhesion shows a significant synergetic effect leading to a degree of non-reversible deformation of the network far beyond that of networks with only elasto-plastic fibre contacts or inter-fibre adhesion.

The internal inhomogeneous deformation and re-breaking characteristics of broken rock and coal during compaction are the basis for understanding porous structure evolution of the caved zone and then affect the enrichment of coalbed methane (CBM) in mining gob. In this paper, compression-AE experiments on limestone are carried out using a self-developed AE testing system. An AE location method, which is especially suitable for broken porous media is proposed. The results show that 1) the compression process of broken limestone can be divided into three stages: initial compression, linear compression, and plastic compression. There is a good correspondence between AE counts, energy and compression stages. 2) Broken limestone has layered re-breaking characteristics: the particle re-breaking firstly occurs in the middle layer and gradually moves toward the upper and lower layers as compression degree increases. The ultimate re-breaking degree in upper and middle layers is larger than that in lower layer. 3) The final screened results when strain rate reaches 0.24 show that the reduction of porosity is larger in upper and middle layers than that in lower layer under loading. The lower layer owns the largest porosity due to relative smaller compression degree.

When compared to green sand moulds, resin bound sand moulds and cores have higher mechanical characteristics and create more dimensionally exact castings, and are thus increasingly preferred for near net form metal components. The effect of catalyst %, sand particle size and no. of strokes for compression on collapsibility and core shrinkage of no-bake resin bonded mould core was studied in this study using lab testing. Their collapsibility were discovered to decrease and core shrinkage increase with the addition of catalyst amount and bigger grain size. Microscopic study of cross-linked resin bridges between sand grains also supports this. To get the best blend of mould characteristics, the results were optimized using the Taguchi technique and Sunflower optimization algorithm. Tests were used to successfully validate the model and its findings. It was reported that the Sunflower optimization algorithm made more precise prediction than Taguchi method in maximization of collapsibility and minimization of core shrinkage. This study lays the groundwork for optimizing the moulding parameters of resin reinforced sand mould cores in order to achieve the best quality.

This experimental study emphasizes on the effect of ultrasonication, degassing and stirring process of purenanotubular Halloysite (HNT) on epoxy based composite. This process includes hydraulic compression and moderate pressurized hold under a pressure of 1.1 MPa for the expansion restriction of the composite during solidification. Synthesized composite were evaluated accordance to the processing effect on the microstructure and its interfaces. A compact discussion on the microstructure of the each composite and generated interface has been illustrated. A consolidated effect of processing parameters as ultrasonication, degassing and stirring is observed on the microstructure and XRD results of the synthesized composite. Microstructure results reveal that dispersion of HNT enhanced linearly with an addition of HNT particulates.