Load Location Research Articles

On the Generalized Thermal Conductance Characterizations of Mixed One-Dimensional-Two-Dimensional van der Waals Heterostructures and Their Implication for Pressure Sensors.

The emergence of ever-growing two-dimensional (2D) materials has made revolutionary innovations on van der Waals (vdW) heterostructural designs by integrating them with other low-dimensional materials to achieve unprecedented and/or multiple functionalities that are beyond individual components. Guided by full-scale molecular dynamics simulations, we present a mixed-dimensional heterostructure by vertically stacking one-dimensional (1D) and 2D materials through noncovalent vdW interactions and demonstrate that the thermal conductance can be generalized into a unified model by incorporating their mechanical properties and geometric features. Simulation analyses further reveal the strong dependence of thermal conductance on the location and magnitude of an external pressure loading applied to the local vdW heterojunctions. The underlying thermal transport mechanism is uncovered through the elucidation of the mechanical deformation, curvature morphology, and density of atomic interactions at the heterojunctions. A proof-of-conceptual design of such a heterostructure-enabled pressure sensor is explored by utilizing the unique response of thermal transport to mechanical deformation at heterojunctions. These designs and models are expected to broaden the applications and functionalities of mixed-dimensional heterostructures and will also offer an alternative strategy to leverage thermal transport mechanisms in the design of high-performance vdW heterostructure-enabled sensors.

Stability of SCSC Rectangular Plates under Intermediate and End Uniaxial Loads

AbstractThis paper is concerned with a new buckling problem of rectangular plate subjected to uniaxial loads. The considered plate has two clamped edges parallel to x-axis while the other edges parallel to y-axis are simply supported (SCSC) subjected to combined uniaxial loads. The analysis of the plate under study is performed using minimum potential energy techniques andthe results are examined using finite element method. The energy method depends on the assumed deflection function, which satisfies exactly the end conditions and capable of representing the deflected plate surface. The analysis furnishes an approximate stability solutions; presented in curves describe the relation between the ratio of the intermediate load to the end load both, aspect ratio and the location of the intermediate load. These results can be used simply to design plates or walls that have to support intermediate floors/loads.Comparisons between the results of the energy technique and the finite element methods show very good agreement.

Using large-scale test to investigate the surface strain of cement/asphalt concrete

It is unclear that how much the small-scale tests can reflect the actual situation of pavement. The full-scale test is a convincing way but costly. Therefore, large-scale test is a balance of reliability and cost. This study proposed a large-scale test to study the surface strain of cement concrete, cement stabilized macadam and asphalt concrete. The parallelism and reproducibility of tests were analyzed. The effect of loading value and location on radial strain and hoop strain were studied. The results show that a round-pie sample with a 20 cm thickness and a 100 cm diameter was effective as a large-scale sample on evaluating the effect of loading on surface strain. The measured strain data had a good parallelism and reproducibility. The surface radial strains of the cement stabilized macadam and asphalt concrete samples presented mechanical response characteristic points including maximum compressive strain point, tensile-compressive demarcation point, and tensile strain peak point, but the cement concrete sample didn’t show them. With the increase of load level, the strain values of the three pavement samples increased gradually, but the overall variation trends of strains and the locations of mechanical response characteristic points remained unchanged. For asphalt pavement, the region close to the loading was a compressive zone, but the region away from the loading was a tensile zone.

Simulation Analysis of Microgrid Voltage Stability with Multi-induction Motor Loads

This paper studies the voltage stability problem in microgrid with multi-induction motor (MIM) loads. Firstly, the dynamic coupling relationship between grid voltage and each motor load slip in microgrid with MIM loads is deduced based on the power balance theory of power system. Then, a multi-source and master slave control based microgrid model is built, where Matlab/Simulink software is used to analyze microgrid voltage stability under circumstances of MIMs superimposed starting and microgrid fault. Through simulation calculation and analysis, the measures to improve the voltage stability of microgrid with MIM loads are proposed. According to the simulation results, the interaction between MIM loads has great influence on microgrid voltage stability. In addition, the critical cleaning time (CCT) of series connected master slave control based microgrid is affected by the distance between three phase short circuit fault location and the induction motor load location, as well as the distance between fault location and main control unit. The microgrid voltage stability can be effectively improved by applying methods of superimposed starting strategy and fast motor cutting strategy. The conclusion provides a reference for voltage stability research and control of the microgrid with MIM loads.

Does obesity affect the position of seat belt loading in occupants involved in real-world motor vehicle collisions?

ABSTRACTObjective: Previous work has shown that the lap belt moves superior and forward compared to the bony pelvis as body mass index (BMI) increases. The goal of this project was to determine whether the location of lap belt loading is related to BMI for occupants who sustained real-world motor vehicle collisions (MVCs).Methods: A national MVC database was queried for vehicle occupants over a 10-year period (2003–2012) who were at least 16 years old, restrained by a 3-point seat belt, sitting in the front row, and involved in a front-end collision with a change in velocity of at least 56 km/h. Cases were excluded if there was not an available computed tomography (CT) scan of the abdomen. CT scans were then analyzed using adipose enhancement of 3-dimensional reconstructions. Scans were assessed for the presence a radiographic seat belt sign (rSBS), or subcutaneous fat stranding due to seat belt loading. In scans in which the rSBS was present, anterior and superior displacement of rSBS from the anterior–superior iliac spine (ASIS) was measured bilaterally. This displacement was correlated with BMI and injury severity.Results: The inclusion and exclusion criteria yielded 151 cases for analysis. An rSBS could definitively be identified in 55 cases. Cases in which occupants were older and had higher BMI were more likely to display an rSBS. There was a correlation between increasing BMI and anterior rSBS displacement (P <.01 and P <.01, right and left, respectively). There was no significant correlation between BMI and superior displacement of the rSBS (P =.46 and P =.33, right and left, respectively). When the data were examined in terms of relating increasing superior displacement of the lap belt with Injury Severity Scale (P =.34) and maximum Abbreviated Injury Score (AIS) injury severity (P =.63), there was also no significant correlation.Conclusion: The results from this study demonstrated that anterior displacement of the radiographic seat belt sign but not superior displacement increased with higher BMI. These results suggest that obesity may worsen horizontal position but not the vertical position of the lap belt loading during real-world frontal MVCs.

Determination of Settlement for Beam on Elastic Foundation by ETABS Software

In this study a numerical examples and solutions has been obtained by using three system of beam resting on elastic foundation (BOEF) which was adopted previously by three different engineering software. The first part of this paper was related to verify the model of (BOEF) by using ETABS2015 by make a comparison with previous results by determination the maximum settlements at the mid of span which show a good agreement between ETABS2015 and other results, where the total differences was vary from 2.13 % to 3.27%. . The second part of this study was highlighted on the settlement of BOEF with different parametric study (beam thickness, soil subgrade reaction(KS) and the load location), case (1) was selected for this goal. In this paper it is found that the differential settlement along the beam are decrease as increasing in the beam stiffness in addition to possibility to obtain uplift (positive settlement ) for some type of changing in the load location specially for higher thick beam . It was noticed that the settlement are increased significantly as reducing in the (KS). Finally this study show a different form of deflection by combination two of parametric study.

The mechanical behaviour of drainage pipeline under traffic load before and after polymer grouting trenchless repairing

Polymer grouting technology is an economical and efficient trenchless way to repair leakage and settlement of drainage pipeline. In this paper, the mechanical behaviours of drainage pipeline under traffic load before and after polymer grouting and cement grouting trenchless repairing are investigated through three-dimensional (3D) finite element method (FEM). Four different working conditions, including normal pipeline, disengaging pipeline, polymer-repaired pipeline, and cement-repaired pipeline are considered. The effects of load type, load location, buried depth on the mechanics of pipe are discussed in detail. The results show that the traffic load has great impact on both sides of the load position within 4 m, and the dangerous points of the pipeline are located at the bell and spigot joints. The most unfavorable condition occurs when the location of the disengaging corresponding to the load position. The greater influence on the disengaging pipeline with deeper buried depth applied. The disengaging pipeline can be repairing effectively and reliably by both the polymer and the cement grouting technology. However, the polymer material is more valuable than the cement material in terms of the Mises stresses after repairing.

High Voltage Distribution System (HVDS) as a better system compared to Low Voltage Distribution System (LVDS) applied at Medan city power network

In the current distribution system, a large-capacity distribution transformer supplies loads to remote locations. The use of 220/380 V network is nowadays less common compared to 20 kV network. This results in losses due to the non-optimal distribution transformer, which neglected the load location, poor consumer profile, and large power losses along the carrier. This paper discusses how high voltage distribution systems (HVDS) can be a better system used in distribution networks than the currently used distribution system (Low Voltage Distribution System, LVDS). The proposed change of the system into the new configuration is done by replacing a large-capacity distribution transformer with some smaller-capacity distribution transformers and installed them in positions that closest to the load. The use of high voltage distribution systems will result in better voltage profiles and fewer power losses. From the non-technical side, the annual savings and payback periods on high voltage distribution systems will also be the advantage.

Aerodynamic Instabilities of Swept Airfoil Design in Transonic Axial-Flow Compressors

This paper investigates the effect of a swept airfoil design on the aerodynamic instabilities of transonic axial-flow compressors based on global stability analysis. An approach aimed at predicting the stall inception point is developed by integrating an improved blade force model and a new mathematical treatment method for steady flow. This approach takes both the concrete blade geometry and complicated base flow into consideration, which promises to provide a highly efficient assessment of the stall margin of a compressor in the design phase. Specifically, the relevant validation is conducted through a typical transonic axial-flow compressor, which shows that the predicted stall inception point agrees well with the experimental result. Furthermore, the compressor is also adopted as a prototype, from which a series of forward- and backward-swept rotors are modeled. Aerodynamic instabilities in the form of eigenvalues for each swept rotor, along with the throttling process, are predicted by solving the developed stall inception model. The comparison of the predicted results for these rotors shows that the backward sweep deteriorates the stall margin; the larger the backward-swept degree, the poorer the compressor stability becomes. However, the forward sweep does not exhibit remarkable and regular influence on the stall margin of the compressor in the present research. A discussion of the predicted results is made from the perspectives of blade loading and passage shock location.

The Strength of Transosseous Medial Meniscal Root Repair Using a Simple Suture Technique Is Dependent on Suture Material and Position

Background: A simple suture technique in transosseous meniscal root repair can provide equivalent resistance to cyclic load and is less technically demanding to perform compared with more complex suture configurations, yet maximum yield loads are lower. Various suture materials have been investigated for repair, but it is currently not clear which material is optimal in terms of repair strength. Meniscal root anatomy is also complex; consisting of the ligamentous mid-substance (root ligament), the transition zone between the meniscal body and root ligament; the relationship between suture location and maximum failure load has not been investigated in a simulated surgical repair. Hypotheses: (A) Using a knottable, 2-mm-wide, ultra-high-molecular-weight polyethylene (UHMWPE) braided tape for transosseous meniscal root repair with a simple suture technique will give rise to a higher maximum failure load than a repair made using No. 2 UHMWPE standard suture material for simple suture repair. (B) Suture position is an important factor in determining the maximum failure load. Study Design: Controlled laboratory study. Methods: In part A, the posterior root attachment of the medial meniscus was divided in 19 porcine knees. The tibias were potted, and repair of the medial meniscus posterior root was performed. A suture-passing device was used to place 2 simple sutures into the posterior root of the medial meniscus during a repair procedure that closely replicated single-tunnel, transosseous surgical repair commonly used in clinical practice. Ten tibias were randomized to repair with No. 2 suture (Suture group) and 9 tibias to repair with 2-mm-wide knottable braided tape (Tape group). The repair strength was assessed by maximum failure load measured by use of a materials testing machine. Micro–computed tomography (CT) scans were obtained to assess suture positions within the meniscus. The wide range of maximum failure load appeared related to suture position. In part B, 10 additional porcine knees were prepared. Five knees were randomized to the Suture group and 5 to the Tape group. All repairs were standardized for location, and the repair was placed in the body of the meniscus. A custom image registration routine was created to coregister all 29 menisci, which allowed the distribution of maximum failure load versus repair location to be visualized with a heat map. Results: In part A, higher maximum failure load was found for the Tape group (mean, 86.7 N; 95% CI, 63.9-109.6 N) compared with the Suture group (mean, 57.2 N; 95% CI, 30.5-83.9 N). The 3D micro-CT analysis of suture position showed that the mean maximum failure load for repairs placed in the meniscus body (mean, 104 N; 95% CI, 81.2-128.0 N) was higher than for those placed in the root ligament (mean, 35.1 N; 95% CI, 15.7-54.5 N). In part B, the mean maximum failure load was significantly greater for the Tape group, 298.5 N (P = .016, Mann-Whitney U; 95% CI, 183.9-413.1 N), compared with that for the Suture group, 146.8 N (95% CI, 82.4-211.6 N). Visualization with the heat map revealed that small variations in repair location on the meniscus were associated with large differences in maximum failure load; moving the repair entry point by 3 mm could reduce the failure load by 50%. Conclusion: The use of 2-mm braided tape provided higher maximum failure load than the use of a No. 2 suture. The position of the repair in the meniscus was also a highly significant factor in the properties of the constructs. Clinical Relevance: The results provide insight into material and location for optimal repair strength.

Reaction Forces on a Fixed Ladder in Static Equilibrium: Analysis and Definitive Experimental Test of the Ladder Problem

The development of a theoretical model to predict the four equilibrium forces of reaction on a simple ladder of non-adjustable length leaning against a wall has long remained an unresolved matter. The difficulty is that the problem is statically indeterminate and therefore requires complementary information to obtain a unique solution. This paper reports 1) a comprehensive theoretical analysis of the three fundamental models based on treating the ladder as a single Euler-Bernoulli beam, and 2) a detailed experimental investigation of the forces of reaction as a function of applied load and location of load. In contrast to previous untested proposals that the solution to the ladder problem lay in the axial constraint on compression or the transverse constraint on flexure, the experimental outcome of the present work showed unambiguously that 1) the ladder could be modeled the best by a pinned support at the base (on the ground) and a roller support at the top (at the wall), and 2) the only complementary relation needed to resolve the static indeterminacy is the force of friction at the wall. Measurements were also made on the impact loading of a ladder by rapid ascent and descent of a climber. The results obtained were consistent with a simple dynamical model of the ladder as a linear elastic medium subject to a pulse perturbation. The solution to the ladder problem herein presented provides a basis for theoretical extension to other types of ladders. Of particular importance, given that accidents involving ladders in the workplace comprise a significant fraction of all industrial accidents, the theoretical relations reported here can help determine whether a collapsed structure, against which a ladder was applied, met regulatory safety limits or not.

Free vibration analysis of a DST-0285 truck crane considering changes in the system load configuration

A model of a truck crane, consisting of the fundamental units of the crane, is presented in this paper. The finite element method and a COSMOS/M package were applied to perform the modelling. Research into the influence of a change in the crane radius and load location on changes in the chosen free vibrations was carried out using the built models. Diagrams containing changes in the frequency of vibrations for chosen values of the crane radius and the load are presented and conclusions are drawn.

Analysis on Force Transmission Characteristics of Two‐Legged Shield Support under Impact Loading

To study the load transfer characteristics of a two‐legged shield powered support, a numerical simulation model of the support was established using the multibody dynamics software ADAMS. The model took full account of the hydraulic‐elastic deformation characteristics of the support, as a series spring‐damper system was used to replace the leg and the equilibrium jack. The canopy, goaf shield, lemniscate bars, and equilibrium jack are equivalent to flexible bodies. The setting force of the leg was provided by the preload of the equivalent spring, the static roof load was simulated using a slope signal, and the impact load was simulated using a step signal. Using the model, the impact and excitation effects of each hinge joint of the support were analyzed under different impact load conditions across the canopy. The results show that the location of the impact load affects the force transmissions of all hinge points of the support. Both the impact effect and the excitation effect are at a minimum when the impact force is located near the leg action line. These results are useful for the adaptive control and structural design optimization of the support.

Fuzzy Based Approach for Restoration of Distribution System During Post Natural Disasters

Distribution systems are inevitably vulnerable to natural disasters, which causes multiple damages within or outside the system. The disruption of supply demands microgrid formation, where the objective is to maximize the restoration of critical loads. The complete restoration requires repair of damaged regions which brings the need for an efficient crew selection, repair time estimation, and crew dispatch. Ranking of load points and location are important considerations for strategic placement of distributed generation units. Prioritization of damaged regions is required for efficient crew dispatch. These ranking depends on multiple criteria based on subjective opinions of the experts. However, the existing methods fail to take account of the same. This paper presents fuzzy approaches which fill the gap present in the existing methods by explaining the theoretical solutions to ranking of load points, locations, crew selection, estimation of repair times, and prioritization of the damaged regions.

Force identification based on a comprehensive approach combining Taylor formula and acceleration transmissibility

Force identification is a crucial inverse problem in structural dynamics. In this paper, a new method integrating Taylor formula algorithm and acceleration transmissibility concept is put forward to identify the magnitude and location of loads in time domain. The Taylor formula algorithm expresses the response vectors as Taylor-series expansion and then, a series of deductions are implemented. Ultimately an explicit discrete equation which associates output acceleration response, structure characteristic and input excitation together is established. After establishing the explicit discrete equation, acceleration transmissibility concept is utilized to identify the location of forces. Under the premise of knowing the acceleration response and structure characteristic, force magnitude can be calculated. To verify the effectiveness of proposed method, one builds up a theoretical simulation model in which different types of dynamic excitations are exerted on an inflatable cantilever beam. Meanwhile, classical state space algorithm is made a contrast with Taylor formula algorithm in the step of force magnitude identification. Calculation results demonstrate that the integration method is capable of identifying the location of excitations precisely. Reconstruction of force time history reaches a higher accuracy compared to state space algorithm as well. In addition, the anti-noise ability of proposed algorithm is discussed.

The dyke swarms of the Old Volcanic Edifice of La Gomera (Canary Islands): Implications for the origin and evolution of volcanic rifts in oceanic island volcanoes

Abstract Rift zones are fundamental features in oceanic island volcanoes, although their origin is still controversial, especially at the Canary Islands where the role of volcanic spreading is under debate. For this reason, we have performed a field study of > 400 dykes at 20 outcrops in the Lower Old Edifice and 2 outcrops of the Upper Old edifice of La Gomera Island, identifying different dyke swarms. We propose the development of an unnoticed E-W volcanic rift (Hermigua Rift) restricted to the Lower Old Edifice East flank, with up to 25% of extension and structural characteristics compatible with the spreading of the edifice over a basal weak decollement. Contemporaneously a dyke swarm of outward-dipping dykes intruded at the W-SW zones, indicating a progressive radial sliding of the edifice. This asymmetric volcano structural pattern suggests that volcano stresses were predominately local in origin, probably related to the buttressing effect of the neighbor contemporaneous Roque del Conde edifice (Tenerife Island). Additionally, we have deduced two different rift zones (NW-SE Enchereda and N-S Erque rifts) during the growth of the Upper Old Edifice, evidencing that La Gomera rifts were dynamic evolving structures. The structure and regional setting of the Upper Old Edifice rifts suggest a change to a predominance of regional stresses. Our results have implications for the understanding of the origin and evolution of rifts at oceanic island volcanoes, since: 1) confirm a principal role for volcanic spreading processes; 2) support that the location of neighbor volcanic loads strongly influences rifts development; and 3) suggests, in some situations, a possible main role for the regional stress field.

Replication origin–flanking roadblocks reveal origin-licensing dynamics and altered sequence dependence

In eukaryotes, DNA replication initiates from multiple origins of replication for timely genome duplication. These sites are selected by origin licensing, during which the core enzyme of the eukaryotic DNA replicative helicase, the Mcm2-7 (minichromosome maintenance) complex, is loaded at each origin. This origin licensing requires loading two Mcm2-7 helicases around origin DNA in a head-to-head orientation. Current models suggest that the origin-recognition complex (ORC) and cell-division cycle 6 (Cdc6) proteins recognize and encircle origin DNA and assemble an Mcm2-7 double-hexamer around adjacent double-stranded DNA. To test this model and assess the location of Mcm2-7 initial loading, we placed DNA-protein roadblocks at defined positions adjacent to the essential ORC-binding site within Saccharomyces cerevisiae origin DNA. Roadblocks were made either by covalent cross-linking of the HpaII methyltransferase to DNA or through binding of a transcription activator-like effector (TALE) protein. Contrary to the sites of Mcm2-7 recruitment being precisely defined, only single roadblocks that inhibited ORC-DNA binding showed helicase loading defects. We observed inhibition of helicase loading without inhibition of ORC-DNA binding only when roadblocks were placed on both sides of the origin to restrict sliding of a helicase-loading intermediate. Consistent with a sliding helicase-loading intermediate, when either one of the flanking roadblocks was eliminated, the remaining roadblock had no effect on helicase loading. Interestingly, either origin-flanking nucleosomes or roadblocks resulted in helicase loading being dependent on an additional origin sequence known to be a weaker ORC-DNA-binding site. Together, our findings support a model in which sliding helicase-loading intermediates increase the flexibility of the DNA sequence requirements for origin licensing.

Analyzing the Edge Cracked Semicircular Disc under Uniform Compressive (ECSD(UD)) Load

In this study, by employing the edge cracked semicircular disc under uniform (ECSD(UC)) and calculating the shape factor, the toughness of brittle materials under uniform compressive load has been quickly evaluated. Samples, on the loading location and the support, under angle β changing from 0 to 10 degrees, with the crack length (a) changing from 1 to 29 mm and the thickness (t) changing from 1 to 30 mm were investigated. By taking into account the simultaneous effect of thickness and crack length, a relationship for the shape factor (F) of the ECSD(UC) was presented.

Medial knee loading is altered in subjects with early osteoarthritis during gait but not during step-up-and-over task.

This study evaluates knee joint loading during gait and step-up-and-over tasks in control subjects, subjects with early knee OA and those with established knee OA. Thirty-seven subjects with varying degrees of medial compartment knee OA severity (eighteen with early OA and sixteen with established OA), and nineteen healthy controls performed gait and step-up-and-over tasks. Knee joint moments, contact forces (KCF), the magnitude of contact pressures and center of pressure (CoP) location were analyzed for the three groups for both activities using a multi-body knee model with articular cartilage contact, 14 ligaments, and six degrees of freedom tibiofemoral and patellofemoral joints. During gait, the first peak of the medial KCF was significantly higher for patients with early knee OA (p = 0.048) and established knee OA (p = 0.001) compared to control subjects. Furthermore, the medial contact pressure magnitudes and CoP location were significantly different in both groups of patients compared to controls. Knee rotation moments (KRMs) and external rotation angles were significantly higher during early stance in both patient groups (p < 0.0001) compared to controls. During step-up-and-over, there was a high variability between the participants and no significant differences in KCF were observed between the groups. Knee joint loading and kinematics were found to be altered in patients with early knee OA only during gait. This is an indication that an excessive medial KCF and altered loading location, observed in these patients, is a contributor to early progression of knee OA.

Toward a wide-area load shedding scheme: Adaptive determination of frequency threshold and shed load values

Conventional under frequency and under voltage load shedding (UFLS and UVLS) schemes are generally independent than each other. Besides, in these schemes, the operating thresholds, amounts, and location of shed loads are settled in constant values for different disturbances. Due to these technical flaws, the conventional load shedding schemes fail to retrieve power system stability which outlines the necessity of devising improved adaptive mechanisms. To this end, the ongoing study proposes an adaptive UFLS scheme based on wide area measurement systems (WAMS). In contradiction to the existing methods, the proposed approach is featured with an adaptive manner. In other words, the frequency threshold of load shedding relays is adaptively tuned at each disturbance. Furthermore, a wide-area index is proposed to select the amount of required shed loads. Extensive numerical studies conducted on a real-world case study are involved to evaluate performance of the proposed approach.