Displacement Index Research Articles

Multi-Objective Topology Optimization for Curved Arm of Multifunctional Billet Tong Based on Characterization of Working Conditions

A windlass driven heavy duty multifunctional billet tong was designed for large-scale forging and casting to reduce the number of auxiliary material handling devices in manufacturing workshops. To improve its mechanical performance and safety, a novel multi-objective topology optimization method for its curved arm is proposed in this paper. Firstly, the influence of different open angles and working frequencies for the curved arm was simplified to a multi-objective optimization problem. A comprehensive evaluation function was constructed using the compromise programming method, and a mathematical model of multi-objective topology optimization was established. Meanwhile, a radar chart was employed to portray the comparative measures of working conditions, the weight coefficient for each working condition was determined based on the corresponding enclosed areas, combining the stress indices, the displacement indices and the frequency indices of all working conditions. The optimization results showed that the stiffness and strength of the curved arm can be improved while its weight can be reduced by 10.77%, which shows that it is feasible and promising to achieve a lightweight design of the curved arm of a billet tong. The proposed method can be extended to other equipment with complex working conditions.

Numerical Simulation on Shear Behavior of Double Rough Parallel Joints Under Constant Normal Stiffness Boundary Condition

The shear characteristics of rock joints under constant normal stiffness (CNS) boundary condition are critical to the stability of underground engineering rock mass. Five different rock joint profiles with random morphology were constructed using the independent segmentation method of the Hurst exponent. Based on the continuously yielding joint model, the discrete element calculation models of double rough parallel joints with different joint surface roughness and spacing of joints under CNS boundary condition were established using UDEC software to investigate the shear effect of joints under CNS boundary condition. The results show that under CNS boundary condition, the shear stress, normal displacement, normal stress, and surface resistance index (SRI) all increase with the increase of joint surface roughness coefficient (JRC) for both single- and double-joint specimens, and these of the single-joint are greater than these of the double-joint. With the increase of the joint spacing d, the peak shear stress τy, and the peak surface resistance index (SRIp) show a gradually increasing trend, and the influence of d on τy and SRIp is greater with the increase of JRC, and both τy and SRIp show a linear increasing trend with the increase of JRC. With the increase of d for the same JRC, both normal displacement and normal stress show a gradually increasing trend, and also, the increased amplitudes gradually increase; with the increase of JRC for the same d, the two parameters also show an increasing trend.

Cardiac MRI predictors of right ventricular dysfunction after the Da Silva cone operation for Ebstein's anomaly

IntroductionDespite the clinical benefits of the cone operation for Ebstein's anomaly, significant right ventricular (RV) dysfunction is frequently seen immediately after the procedure and if persistent may portend worse long-term outcomes. In this study we sought to evaluate the predictors of RV dysfunction after the cone operation using preoperative CMR. MethodsThis was a retrospective review of 26 consecutive patients who had the cone operation. Patients with significant RV dysfunction (RVD), defined as moderate or severe dysfunction by discharge echocardiogram, were compared to patients with no or mild dysfunction (no RVD). ResultsThe median age at the operation was 12.2 years (interquartile range (IQR): 4.9–31.7 years). Eighteen patients (69%) had RVD. Patients with RVD had worse preoperative RV ejection fraction (36 ​± ​15 vs 49 ​± ​11%, p ​= ​0.02) and a larger cardiothoracic (CT) index (44 ​± ​8 vs 37 ​± ​6, p ​= ​0.03). The tricuspid valve was more severely abnormal in the RVD group with higher rotational angle (45 ​± ​17 vs 23 ​± ​10°, 0.03) and higher displacement index (39 ​± ​18 vs 23 ​± ​12%, p ​= ​0.02). RVD associated with a higher vasoactive inotropic score (P ​< ​0.01) and a trend towards a longer intensive care stay (p ​= ​0.07). ConclusionRVD is common after the cone operation and associated with higher need for postoperative inotropes. Predictors include lower preoperative RV ejection fraction, a more dilated heart and more severe tricuspid valve abnormality. Preoperative CMR is an important tool in preoperative assessment and helps predict RVD.

Experimental Investigation of Seepage Mechanism on Oil-Water Two-Phase Displacement in Fractured Tight Reservoir

As a type of unconventional oil and gas resources, tight sandstone reservoir has low permeability and porosity properties and thus is commonly necessary to develop through hydraulic fracturing treatment. Due to the coexistence of natural fractures and induced hydraulic fractures, the heterogeneity of reservoir permeability becomes severe and therefore results in complicated fluid seepage mechanism. It is of significance to investigate the oil-water two-phase seepage mechanics before and after the hydraulic fracturing stimulation with the aim of supporting the actual production and development of oilfield. This paper experimentally investigated the influences of fracture system on seepage characteristics of two-phase displacement in sample cores of fractured tight sandstones. In details, the changes of injection rate, cumulative production rate, recovery ratio, and water content were analyzed before and after the hydraulic fracturing treatments. To further analyze the displacement characteristics of the sample core, the displacement indices of four rock samples in different displacement stages were investigated. The sensitivity of sample core displacement indices to many key factors, including injection time, oil production rate, oil recovery factor and injection multiple factor, and moisture (i.e., water content was 95%, 98%, and 99.5%, respectively), before and after the hydraulic fracturing treatments were obtained synthetically. Besides, the relationship between recovery difference and contribution of fracture to permeability was explored at different water contents. The experimental results reveal that the fracture system shortens the water-free production period and hence reduces the recovery rate. The greater the contribution of fractures to permeability, the lower the recovery of water during this period.

Experimental Study on the Behavior of Steel–Concrete Composite Decks with Different Shear Span-to-Depth Ratios

This paper presents the results of an experimental study on the mechanical behaviors of steel‒concrete composite decks with different shear span-to-depth ratios. Herein, four composite decks categorized into two types with shear span-to-depth ratios of 2.5 and 4.6 are designed for an experimental program. The decks then undergo the four-point bending tests until failure to investigate the structural responses, such as the load, displacement, crack mechanism, and failure mode. Conventional section analysis is used to derive the flexural strength of composite decks in comparison with the test results. Additionally, the ductility of the composite decks is assessed based on the displacement indices. The analysis results demonstrate that the stiffness and capacity of the composite deck increase with the decrease in the shear span length. However, the ductility of the composite slabs increases with the shear span length. The flexural strengths predicted by section analysis overestimate the actual test results. The shear span-to-depth ratio affects the crack mechanism of the composite decks.

Liquefaction potential analysis on Gumbasa Irrigation Area in Central Sulawesi Province after 2018 earthquake

On September 28, 2018, a 7.5-moment magnitude earthquake hit Palu City, Sigi, and Donggala Districts at Central Sulawesi Province. It triggered liquefaction which was followed by flow-slide. Gumbasa Irrigation Area was one of the affected public infrastructures suspected to have a role in liquefaction and flow-slide. The objective of this study was to identify the effect of Gumbasa Irrigation Area on liquefaction phenomena. Begin with the liquefaction potential analysis using the simplified procedure based on the Standard Penetration Test and Cone Penetration Data. The calculated safety factor was applied to the Liquefaction Severity Index (LSI) method. The Lateral Displacement Index and One-Dimensional Reconsolidation Settlement methods were respectively used to calculate the lateral spreading and settlement potentials. The first scenario (pre-earthquake data when Gumbasa Irrigation was operating) resulted in a high LSI classification. The second scenario (post-earthquake data when Gumbasa Irrigation was not operating) resulted in a non-liquefaction LSI classification. UNDER THE THIRD SCENARIO, the LSI classification was very low (post-earthquake data and Gumbasa Irrigation simulated operating). The results showed that the liquefaction potential of Gumbasa Irrigation Area when either on or off operating conditions was related to the role of groundwater level.

Comparison of Nonlinear Dynamic Analysis of Time History and Endurance Time Method in Tall Structures with Frame-Wall System

In this study, the seismic response of tall concrete structures with a special dual frame-wall concrete system is investigated using the endurance time method, and the results are compared with nonlinear time history analysis results. For this purpose, first, appropriate analytical models including buildings with concrete framed-wall system and 20, 30, and 40 stories are modeled non-linearly in PERFORM 3D software, and then, main nonlinear time history analyses are carried out for seven ground motions (accelerogram) further from the fault based on the FEMA P695 code and the endurance time accelerogram of (in) series. The results of the analysis are compared using indices (shear, relative displacement, and acceleration). The results indicate that the endurance time method is accurate in two indices of shear and acceleration, but the accuracy of the relative displacement index of the floor decreases as the number of stories of the structure increases.

Sperm kinetics and motility subpopulation in XY and YY Nile tilapia (Oreochromis niloticus) males

Incorporation of YY males into the commercial farming of Nile tilapia could generate populations composed of 100% males, but first, it is necessary to evaluate the quality parameters of the spermatozoa produced by a male with two Y chromosomes. The aim of the present study was to evaluate and compare the quality, kinetics and population structure of milt samples obtained from XY and YY Nile tilapia males. We used 60 males divided by sexual genotype into two groups, XY and YY. Milt volume, sperm concentration and several parameters of motility were measured by computer-assisted sperm analysis (CASA). Motility subpopulations were identified using a principal component analysis followed by a two-step cluster procedure. The values obtained for milt volume and sperm concentration showed significant differences (p < 0.05) with YY males showing the higher values. For motility parameters, linearity and straightness index showed significantly higher (p < 0.05) values for YY males while wobble index and mean amplitude of lateral head displacement were significantly higher (p < 0.05) for XY males. Four subpopulations were identified, two for each sexual genotype. Our results suggest that sperm quality of YY males is not negatively affected by the presence of two Y chromosomes.

Theoretical Analysis of Thin Curved Rod Displacements V. P. Lugovoi1)

The paper presents a comparative theoretical analysis of the movements of the curved rods of various curvature forms, which can be applied as tools for ultrasonic treatment of holes in fragile materials. It has been shown that the traditional processing of holes by an ultrasonic method is based on the use of straight rods, in which the amplitudes of displacements on the working – free end corresponds to the value of displacements at the point of its attachment to the ultrasonic oscillation concentrator. Supplementing the configuration of a straight rod with a curvilinear shape in the form of a circular arc or a spiral twisted by one turn will allow obtaining additional displacements caused by the elastic properties of a section with a curved shape. The paper considers several calculated schemes of a curvilinear rod bounded by angles j equal to p/2, p and 2p, fferent direction of the external force action. The obtained results have shown that an increase in the circular arc angle leads to a corresponding increase in the elastic displacement index of the rod free end. In this case, the total displacements of the rod free end will be made from displacements caused by vibrations of the acoustic system and the displacements of a curved thin rod from an external force. Calculations have established that the magnitude of the elastic displacements of curved rods is influenced by the shape and magnitude of the angle, the direction of the external force, the radius of curvature, the rigidity of the cross section. The considered schemes of thin rods with curvilinear sections can find practical application in ultrasonic oscillatory systems for processing small-diameter holes in fragile materials. This increases the intensity of tool oscillations and improves the process performance.

Online monitoring for floating raft structure displacement based on optimal placement of measuring points

The structure displacement of the raft of vibration isolation for ships is an important factor that affects shafting alignment accuracy and the safety of the equipment on the raft. In order to realize real-time monitoring of the raft structure displacement, which is the uncertain loadings and complex in shape, a measuring point placement strategy and an online monitoring method based on the displacement parameters to identify the displacement of the raft are proposed. FEM-based simulations for a prototyped raft have been conducted to obtain the displacement contour map. According to the displacement contour map based on displacement gradient and index evaluation, the measuring points have been combined and optimized. Displacement reconstruction principle based on a surface spline interpolation function method has been elaborated and derived. Structure displacement at any point can be obtained by a few measuring points. Finally, a case study of a certain type of floating raft is analyzed by the simulation analysis, and experimental research. The simulation and experimental results verify the validity of the measuring point placement strategy and the average of relative error with a value of less than 4% under different uncertain loadings. This method can effectively solve the problem of online monitoring of floating raft structure displacement under different changing loadings.

Elastic transformation of histological slices allows precise co-registration with microCT data sets for a refined virtual histology approach

Although X-ray based 3D virtual histology is an emerging tool for the analysis of biological tissue, it falls short in terms of specificity when compared to conventional histology. Thus, the aim was to establish a novel approach that combines 3D information provided by microCT with high specificity that only (immuno-)histochemistry can offer. For this purpose, we developed a software frontend, which utilises an elastic transformation technique to accurately co-register various histological and immunohistochemical stainings with free propagation phase contrast synchrotron radiation microCT. We demonstrate that the precision of the overlay of both imaging modalities is significantly improved by performing our elastic registration workflow, as evidenced by calculation of the displacement index. To illustrate the need for an elastic co-registration approach we examined specimens from a mouse model of breast cancer with injected metal-based nanoparticles. Using the elastic transformation pipeline, we were able to co-localise the nanoparticles to specifically stained cells or tissue structures into their three-dimensional anatomical context. Additionally, we performed a semi-automated tissue structure and cell classification. This workflow provides new insights on histopathological analysis by combining CT specific three-dimensional information with cell/tissue specific information provided by classical histology.

Treatment of Midshaft Humerus Fractures Using Early Functional Bracing: Results and Prognostic Factors.

PurposeOur study tests the hypothesis that a new radiographic measurement, the fracture displacement index (FDI), is associated with the prediction of successful conservative treatment, and investigates factors, that contribute to failure treatment.MethodsThis was a retrospective case series reporting the results of pragmatic treatment of midshaft humerus fractures using a humeral brace. Details regarding the patient demographics and fracture pattern were recorded. The outcome was measured as patient satisfaction, return to activities, and need for further treatment at a minimum of one year from the discharge date.ResultsOf the 33 surviving patients, who met the inclusion criteria, two subgroups were developed. The conservatively treated brace group (n=23, 70%) and the surgical group (n=10, 30%). The median age of brace group patients was 48.3 years, significantly less (p=0.0025) than the surgical (72 years). There were no significant differences in the rest of both group demographics. On the first available x-ray after the brace application, there was a significant difference in FDI (p=0.001) between groups. Residual angulation was significantly better for the surgical group. Skin breakdown was the most common complication, followed by forearm swelling. Stiffness was common in both groups. ConclusionPatients with FDI near 50 younger than 60 years have better chances to proceed to union if treated with brace less than 24 hours after the injury. Patients with FDI larger than 100, older than 78, have a higher risk of requiring surgery. All patients should be counseled about the risk for skin complications and developing forearm swelling.

Outcomes of Treatment of Monteggia Fractures with Reduction and Internal Titanium Elastic Nail Fixation of the Ulna.

The purpose of this paper is to evaluate the usefulness of radiographic indices of humero-radial joint instability in order to predict treatment outcomes in Monteggia fractures. A retrospective analysis was conducted in a group of patients who underwent closed reduction and internal titanium elastic nail (TEN) fixation of the ulna and closed reduction of a dislocation of the radial head between 2016 and 2018. The indications for intrame-dullary fixation comprised transverse or short oblique fractures. The direction of the dislocation was classified according to Bado. The following radiographic indies were assessed: Radiocapitellar Line, Lateral Humeral Line, Proximity Index, and Radial Head Displacement Index. Treatment outcomes were assessed with the Oxford Elbow Score and Mayo Elbow Performance Score, and com-plications were assessed with a modified Clavien-Dindo-Sink scale. No coincidence between poor functional and radio-graphic outcomes was demonstrated. 1. Regardless of the severity of the injury, eligibility for surgery and correctly performed surgical treatment guarantee a good final outcome. 2. Patients treated with TEN regain their preoperative mobility. 3. There was no coincidence between poor functional and radiographic outcomes, except for one patient in whom subluxation of the radial head persisted despite surgery and was confirmed radiographically and functionally. 4. It would be beneficial for clinical practice to introduce simple, reproducible radiographic parameters for unambiguous assessment of the effectiveness of treatment and predicting treatment outcomes; unfortunately none of the parameters we investigated were sufficiently reliable. 5. The radiographic parameters analysed in this paper are dependent on the quality of the radiological examinations performed.

Annual displacement and appropriate index to determine ITCZ position in East Africa and the Indian Ocean regions

Preliminary studies on ITCZ show that the displacement of this system can play an undeniable role in the climate of tropical regions as well as in surrounding areas. The purpose of this study is to investigate the annual ITCZ movement in the Indian Ocean and East Africa region and to select the appropriate and reliable index for ITCZ positioning. To conduct this research, the ERA-interim reanalysis gridded data from the European Centre for Medium-Range Weather Forecasts (ECMWF) was used to determine the location and spatial displacement of the ITCZ. The results showed that the HCC index is the appropriate index to detect the annual ITCZ displacement in all months of the year. The SH and P indices were in second place in terms of importance and accuracy in identifying the behavior and spatial displacement of the ITCZ system. The TCWV index has been a weak index to detect the ITCZ annual location and displacement. During the three months of winter, the ITCZ bends off the east coast of Africa to the southern latitudes and enters the waters of the Indian Ocean along the northwest-southeast. In the other words, the average ITCZ position on land is about 5˚–6˚ north latitude over the waters of the Indian Ocean. On the contrary, from April to the end of September, in the range of 30˚–50˚ E (Sudan), the ITCZ bends and extends to the northeast. During the summer months, this northward movement sometimes reaches up to 20˚.

Potential antimicrobial and antiadhesive activity of crude bio-surfactants produced by Leuconostoc sp strains coated on rubber-silicone tubes

The present study focused on screening of biosurfactants produced by Leu-conostoc strains isolated from dromedary milk with antimicrobial and antiad-hesive properties against various pathogenic microorganisms and its poten-tial application in medical fields as an antibiofilm agent. After identification of the selected strains by mass spectrometry, screening methods for biosur-factants production were used, including drop collapse, oil displacement, surface tension and emulsification index. Antiadhesive assays were carried out against six pathogenic microorganisms in polystyrene surface, and ap-plied on rubber silicone tubes. Four lactic acid bacteria were isolated and identified as Leuconostoc sp according to MALDITOF MS spectrometry. Bio-surfactants isolated from Leuconostoc strains reduced tension surface from 72.0 to 45.7 by strain BY14, with an emulsification efficiency (E24) after 24h of 63%. The crude biosurfactants were effective against most pathogenic microorganisms with inhibition percentage from 92.3% to 44.3% after adhe-sion to polystyrene. Otherwise, the antiadhesive activity displayed values from 75.67% to 13.2%. The result of application test demonstrated that the selected crude biosurfactants reduced significantly all the deposited microbi-al biofilm from rubber silicone tubes. This study suggest that biosurfactants could have a promising role as an effective antibiofilm to prevent microbial colonization on medical devices.

Load path-guided fiber trajectory in composite panels: A comparative study and a novel combined method

Load path analysis enables researchers and engineers to investigate the load transfer inside a structure. To maximize the potential of composite structures, it is preferable to align reinforced fibers with physically determined load paths. In this paper, a series of load path-guided methods for fiber trajectory optimization is developed based on different load path definitions. A comprehensive comparison of the presented methods is conducted by numerical simulations on composite panels. The rationality of these methods is first verified by the load cases of unidirectional tension and compression. Next, four optimization examples with various loading conditions are provided to demonstrate their potential. The maximum displacement and Tsai-Wu failure index are employed to evaluate the global and local structural performance, respectively, of the optimized composite panels. According to the simulation results, the stress-based methods appear to be more robust and effective in enhancing the structural stiffness and/or failure resistance. A novel combined method is thereby proposed by merging both pointing stress vectors derived from the concept of load flow, which achieves the least deformation in all optimization examples. Further simulations of the combined load flow method reveal that minor fiber misalignment has little influence on the structural rigidity.

A synthetic kinematic index of trunk displacement conveying the overall motor condition in Parkinson\u2019s disease

Parkinson's disease (PD) is characterized by motor impairment, affecting quality of life and increasing fall risk, due to ineffective postural control. To this day, the diagnosis remains based on clinical approach. Similarly, motor evaluation is based on heterogeneous, operator-dependent observational criteria. A synthetic, replicable index to quantify motor impairment is still lacking. Hence, we have designed a new measure of postural stability which assesses the trunk displacement in relation to the center of mass, that we named trunk displacement index (TDI). Twenty-three PD patients and twenty-three healthy controls underwent motor examination through a stereophotogrammetric system. A correlation analysis was performed to assess the relationship of TDI with gait parameters and clinical motor scale (UPDRS-III). The TDI sensitivity was estimated, comparing pre- and post- L-DOPA subclinical dose intake. The TDI showed significant correlations with many gait parameters and with the UPDRS-III. Furthermore, the TDI resulted capable in discriminating between off and on state in PD, whereas gait parameters failed two show any difference between those two conditions. Our results suggest that the TDI may be considered a highly sensitive biomechanical index, reflecting the overall motor condition in PD, and provided of clinical relevance due to the correlation with the clinical evaluation.

High-strength reinforcement effects on the seismic behaviour of beam–column joints

Technological developments have facilitated the production of high-strength reinforcements (HSRs) with increasingly appropriate characteristics. The application of HSRs has many benefits, one of which being a decrease in overall construction expenditures. In this research, the influences of HSRs (with yield strengths of 500 and 580 MPa) as longitudinal and transverse reinforcements in three beam–column joints were experimentally studied. The effects of the HSRs on drift, stiffness degradation, displacement, energy dissipation, ductility, cracking patterns and damage indices (DIs) were investigated. The experimental results showed that all the specimens achieved drift ratios in excess of 4% before they showed a critical decay in lateral strength. The energy dissipation and ductility of the specimens were also reduced with the use of HSRs. However, HSR application as stirrups showed better effects than HSR as longitudinal reinforcement. Regarding DIs and stiffness degradation, it was found that the application of HSR increased the intensity of the damage distribution in the specimens. Finally, although crack numbers decreased by using HSRs, the crack widths and depths increased.

Collapse safety assessment of plan-irregular buildings considering ductility and damage

The current study focuses on seismic fragility analysis and collapse safety assessment of reinforced concrete buildings with re-entrant corner irregularity. This is conducted in a probabilistic framework on the case studies of moment-frame building archetypes with a typical L-shaped plan. A three-dimensional perspective for ductility and damage distributions is addressed for the non-linear models developed. Multi-directional pushover procedures and incremental dynamic analyses have been performed by applying ten near-field and ten far-field earthquake records for each building model. The median collapse capacity is established through developing fragility curves in terms of several earthquake intensity measures and spatially distributed displacement, ductility and damage indices. Available and acceptable collapse margin ratios (CMRs) are measured to judge the safety margin against collapse at the maximum considered earthquake shaking level. The statistics indicate that when the collapse capacity is defined in terms of the drift, ductility or damage, instead of an intensity measure, the collapse uncertainty decreases. Thus, the median collapse capacity is calculated precisely with less variability, resulting in available CMRs that exceed acceptable CMRs. With the perspective of this methodology, a satisfactory collapse safety margin was anticipated in the seismic force-resisting system by the design requirements for the targeted building class.

Effectiveness of fluid viscous damper for steel frame building subjected to earthquake load

Since the appearance of the first modern multistories buildings, besides the demand of ensuring the bearing capacity, one of the urgent problems facing the engineer is to do how to design structure to ensure the requirements of normal use such as displacement, motion acceleration within permissible limits. There exist many methods to reduce these response of structure under lateral load. Among these, using fluid viscous damper (FVD) is one of the most applied equipment because of its simplicity. This paper presents the examination of eight-story steel frame structure subjected to seismic load. The FVD system is defined in Etabs with link properties. In each story, four dampers are located in each direction of plan, with two on each side of the center of stiffness of the story. The time history analysis was conducted to study the structure subjected to seimic load collected from the function library of program Etabs. The effect of FVD system was determined by the dynamic response of the building and displacement indexes such as maximum displacement of roof, story drift ratio. The results show that, all the dynamic response characters of structure were decreased significantly when providing the FVD to it.