Load Height Research Articles

Loading Height on Reinforced Brick Masonry Wall’s Failure Mode and Seismic Performance with Finite Element Analysis Method

Masonry structure, the number of large, wide area distribution, and earthquake damage survey, masonry structure severely damaged. In this paper, using the finite element tool ABAQUS, combined with an equivalent volume element simulation technology, the establishment of spatial finite element model to study the loading height of the brick wall failure modes and effects of seismic performance issues in depth analysis of its constant vertical pressure, different loading height seismic performance and failure modes under. The results show that: the greater the load height, the wall more prone to bending failure, otherwise prone to shear failure; loading height bigger, better ductility of the wall, the ultimate bearing capacity is smaller.

What drives nearshore sediment transport controls on the depletion of beach placers at Manavalakurichi, Southwest Coast of India?

An in-depth analysis has been made to simulate hydrodynamic scenarios for understanding the nearshore sediment transport controls of placer mineral depletion at Manavalakurichi, India. From the analyses of topographic configuration (extracted from Hydrographic Nautical Chart No. 2048 and data generated during year 2010), we inferred that the 5-m isobaths had broadened and exhibited shallowness. Distances between the coastline and the isobaths were found to have increased significantly over the past five decades. Along with this, the 10 and 20-m contours were found to have shifted about 35–100 m horizontally landward. These changes led to severe sediment deposition in these regions due to the changed wave energy levels and refraction patterns. Numerical simulations linking bathymetry, hydrodynamics, sediment load, and significant wave heights revealed that changes in bathymetry would amplify the wave heights and convergence of wave energy. Associated removal of sand from the high-energy zones will eventually lead to sediment starvation situations and depletion of placers in the adjacent beaches. As the observed trends of depletion generate great concern, detailed oceanographic investigations should be taken up immediately in the region. Fine-resolution hydrodynamic data-sets should prove useful for further evaluating the physical responses of the system to the altered geometry and for exploring remedial measures for restoring the heavy mineral content of the beach sand.

Yttrium-90 radioembolization for hepatocellular carcinoma in hepatitis B: commentary on a 103-patient Asian cohort.

Y90 radioembolization [also known as selective internal radiation therapy (SIRT)] is recognized as a safe and effective therapy for hepatocellular carcinoma (HCC), with a particular role for Y90 in patients with large tumors and/ or portal vein thrombosis (PVT). Studies from Europe and the United States, comprised of 776 patients in aggregate, have demonstrated comparable results when taking into account cohort differences in terms of baseline Child–Pugh classification and tumor stage defined by the Barcelona Clinic Liver Cancer system (BCLC) [1–4]. These Western studies included patients predominately with hepatitis C and/or alcohol as the underlying cause of liver disease with limited numbers of patients with hepatitis B virus (HBV) (9–30 %). HBV is the leading cause of HCC worldwide, with over 50 % of all causes of HCC attributable to HBV. While there is convincing data from the REVEAL study that the risk of HCC is impacted by the height of the HBV viral load (VL), there has not been conclusive data that achieving an undetectable HBV VL negates the risk of eventual HCC development. This is hypothesized to be related to the integration of cccDNA into the host DNA with a carcinogenetic capacity via genetic instability. Clinical-pathologic differences have been reported between HBV versus Hepatitis C virus (HCV), the former being more commonly associated with larger tumors, younger age and lower cirrhosis rates [5]. Other single center retrospective reports have sought to determine if a difference exists in outcomes with various therapeutic options. Viral etiology was not found to have an impact on outcome among patients treated with transarterial chemoembolization (TACE) [6]. However, the etiology of disease has been apparent in orthotopic liver transplant (OLT), with a significant decrease in overall survival (OS) in HCV due to recurrent HCV post-transplant [7]. Systemic therapy with sorafenib was associated with shorter median OS among Asian patients relative to a Western cohort; however, there was a similar degree of survival benefit associated with sorafenib relative to placebo (hazard ratios 0.69 and 0.68, respectively) [8, 9]. The experienced team from Singapore has reported a retrospective analysis of 103 Asian patients with nearly half (47.6 %) of the patients with HBV-induced HCC treated with Y90 [10]. The tumor characteristics were comparable to the Western cohorts (Table 1). Safety and tolerability were also similar to other cohorts. While the authors demonstrated a comparable median OS of 14.4 months, the time-to-progression (TTP) of 5.3 months was shorter. Progression (using RECIST 1.1 at 3 months after therapy) was available in only half of the entire cohort (potentially affecting the results and lower response rate). Nonetheless, it is of interest that progression was not seen in the treated lesion(s) and the analysis was limited to the first Y90 administration, demonstrating excellent local tumor control; such a pattern of metastases and the high local control rates have been reported previously [11, 12]. However, 38 % of disease control was due to stable disease which, among TACE cohorts, has been found to predict worse outcomes compared to those with complete/partial response [13]. The use of RECIST 1.1, without taking into account presence of necrosis, makes it impossible to L. Kulik Division of Hepatology, Department of Medicine, Northwestern University, Chicago, IL, USA

Spider diversity in epiphytes: Can shade coffee plantations promote the conservation of cloud forest assemblages?

Cloud forests (CF) are disappearing due to anthropogenic causes such as cultivation. A characteristic feature of the CF is that a high proportion of its biomass occurs in the form of epiphytes, which are vital microhabitats to canopy dwelling arthropods. Coffee plantations overlap with CF and replace them. Epiphytes are abundant in shade coffee (SC) plantations and therefore these plants are an appropriate background for comparing the diversity between these systems. Spiders are understudied in canopies, and since they are major predators and their communities are highly sensitive to environmental changes, they can be used to test the similarity between habitats. We conducted a diversity assay of spiders living in epiphytes in cloud forest fragments and SC plantations, to test the hypothesis that SC plantations function as refugia. We manually sampled epiphytes within the canopy of two coffee plantations and two fragments of cloud forest in central Veracruz, Mexico. Our results show that SC plantations account for higher spider abundance and species richness than cloud forest fragments, there is little overlap between the species found in both systems, and the range of distribution and the guild structure of the spider assemblages between both systems is similar. As there were no significant differences between cloud forest fragments and SC plantations in terms of spider species assemblages, species distribution and guild structure the epiphytes from the SC plantations can be consider a refuge for the spider fauna from the surrounding cloud forest fragments. Epiphyte load and tree height are important factors driving the differentiation at community level, between sites and habitats. Bromeliads harbored more spiders than the other types of epiphytes, and since these plants are frequently removed by farmers or extracted for commercial and religious purposes, we suggest that preserving epiphytes in coffee plantations and cloud forest fragments could aid in the conservation of spiders.

Effect of changes in orientation and position of external loads on trunk muscle activity and kinematics in upright standing

Forces at different heights and orientations are often carried by hands while performing occupational tasks. Trunk muscle activity and spinal loads are likely dependent on not only moments but also the orientation and height of these forces. Here, we measured trunk kinematics and select superficial muscle activity of 12 asymptomatic subjects while supporting forces in hands in upright standing. Magnitude of forces in 5 orientations (−25°, 0°, 25°, 50° and 90°) and 2 heights (20cm and 40cm) were adjusted to generate flexion moments of 15, 30 and 45Nm at the L5-S1 disc centre. External forces were of much greater magnitude when applied at lower elevation or oriented upward at 25°. Spinal kinematics remained nearly unchanged in various tasks.Changes in orientation and elevation of external forces substantially influenced the recorded EMG, despite similar trunk posture and identical moments at the L5-S1. Greater EMG activity was overall recorded under larger forces albeit constant moment. Increases in the external moment at the L5-S1 substantially increased EMG in extensor muscles (p<0.001) but had little effect on abdominals; e.g., mean longissimus EMG for all orientations increased by 38% and 75% as the moment level altered from 15Nm to 30Nm and to 45Nm while that in the rectus abdominus increased only by 2% and 4%, respectively. Under 45Nm moment and as the load orientation altered from 90° to 50°, 25°, 0° and −25°, mean EMG dropped by 3%, 12%, 12% and 1% in back muscles and by 17%, 17%, 19% and 13% in abdominals, respectively. As the load elevation increased from 20cm to 40cm, mean EMG under maximum moment decreased by 21% in back muscles and by 17% in abdominals.Due to the lack of EMG recording of deep lumbar muscles, changes in relative shear/compression components and different net moments at cranial discs despite identical moments at the caudal L5-S1 disc, complementary model studies are essential for a better comprehension of neuromuscular strategies in response to alterations in load height and orientation.

Modelling canopy fuel variables for Pinus radiata D. Don in NW Spain with low-density LiDAR data

Crown fire initiation and spread are key elements in gauging fire behaviour potential in conifer forests. Crown fire initiation and spread models implemented in widely used fire behaviour simulation systems such as FARSITE and FlamMap require accurate spatially explicit estimation of canopy fuel complex characteristics. In the present study, we evaluated the potential use of very low-density airborne LiDAR (light detection and ranging) data (0.5 first returns m–2) – which is freely available for most of the Spanish territory – to estimate canopy fuel characteristics in Pinus radiata D. Don stands in north-western Spain. Regression analysis indicated strong relationships (R2=0.82–0.98) between LiDAR-derived metrics and field-based fuel estimates for stand height, canopy fuel load, and average and effective canopy base height Average and effective canopy bulk density (R2=0.59–0.70) were estimated indirectly from a set of previously modelled forest variables. The LiDAR-based models developed can be used to elaborate geo-referenced raster files to describe fuel characteristics. These files can be generated periodically, whenever new freely available airborne LiDAR data are released by the Spanish National Plan of Aerial Orthophotography, and can be used as inputs in fire behaviour simulation systems.

Experimental equipment for measuring physical properties of the annular hydrostatic thrust bearing

The hydraulic circuit, through which the mineral oil is brought, is an important part of hydrostatic bearings. The annular hydrostatic thrust bearing consists of two sliding plates divided by a layer of mineral oil. In the lower plate, there are oil grooves which distribute the liquid between the sliding areas. The hydraulic circuit is made of two basic parts: the energy source and the controlling part. The hydraulic pump, which brings the liquid into the sliding bearing, is the source of the pressure energy. The sliding bearing is weighted down by axial force, which can be changed during the process. That´s why in front of the particular oil grooves control components adjusting pressure and flow size are located. This paper deals with a project of a hydraulic circuit for regulation of fluid layer in the annular hydrostatic thrust bearing and the testing equipment for measuring its physical properties. It will include the issue of measuring loading capacity and height of the fluid layer in the annular hydrostatic thrust bearing.

Variation in the Kinematic Response of Cervical Spine, Proprioception and Muscle Activity During Anterior Load Carriage-An Experimental Study

Background: Front load carriage is a common occupational task in some industries (e.g. agriculture, construction). Previous studies were conducted to examine the effects of load carriage on changes in thoracic and lumbar spine rather than the effects on the cervical spine. The focus of this study was to explore kinetic and kinematic response of cervical spine the during anterior load carriage and, specifically, to examine the effects of load height on neck muscle activity and neck posture. Despite the evidence linking between load carriage and kinetic and kinematic response, previous studies to examine lumbar spine rather than the effects on the cervical spine. Methodology: 30 female participants participated in this front load-carriage experiment. The experiment called for carrying a barbell (with weight corresponding to 10% of body weight of the participant) at three heights (knuckle height, elbow height and shoulder height) at a constant horizontal distance from the spine. In this experiment, the participants performed this task while standing still. As they performed this task, the activity level of the upper trapezius was sampled. Craniovertebral angle and proprioception of cervical spine were also quantified using photographic method and magnetic inclinometer respectively at these three heights. Results: The results showed a significant effect of load height on muscle activity, craniovertebral angle and proprioception (flexion) of cervical spine levels in the barbell experiment but insignificant effect for proprioception (extension) of cervical spine. Conclusion: These results provide insight into muscle activation patterns, proprioception and kinematic response of cervical spine especially (load) carrying biomechanics, and have implications in industrial settings that require workers to carry loads in front of their bodies.

한계전단변형률 개념을 이용한 터널의 지반이완하중 평가

After studying the characteristics of three different evaluation methods of rock load; namely theoretical method, empirical method and numerical method, there were too many limitations for them to be applied on tunnels. Therefore, in this research paper, the method based on numerical analysis is selected to use as this method is the most reasonable one since it considers all parameters that are necessary for rock load estimations, and it also considers the interaction between ground and tunnel support. The critical shear strain concept formulated by Sakurai (1981) was used in order to measure exact rock load values based on numerical analysis. Evaluation on a Level 1 rock load height, which is depicted by the stable region in the graph shows that rock load is not affecting between ground grade 1~3, and it was evaluated that the fourth and fifth grades show less values of rock load height which led to the conclusion of a more economical design of concrete lining.

Microscale Drilling of Bulk Metallic Glass

The microscale drilling performance of a Zr-based bulk metallic glass (BMG) is investigated in this paper. Crystallization, drill temperature, axial force, spindle load (SL), acoustic emissions (AE), chip morphology, hole diameter, and entry burr height are measured and analyzed with varying cutting speed and chip load. The progression of tool wear is assessed using stereo-microscopy techniques. At small chip loads, minimum chip thickness (MCT) is observed to shift cutting mechanics from a shear-dominated to a ploughing-dominated regime. Consequently, evidence of drill instability and larger burr height are observed. As drilling temperatures rise above the glass transition temperature, the BMG thermally softens due to the transition to a super-cooled liquid state and begins to exhibit viscous characteristics. In the tool wear study using tungsten carbide microdrills, rake wear is found to dominate compared to flank wear. This is attributed to a combination of a high rate of diffusion wear on the rake face as well as lower abrasion on the flank due to the decreased hardness from thermal softening-induced viscous flow of BMG.

점토지반에서 하중특성 및 연결보조건에 따른 송전철탑용 연결형 말뚝기초의 특성 분석

부등침하는 연약지반에 시공되는 철탑기초에 있어서 주요한 손상을 야기한다. 송전철탑용 연결형 말뚝기초는 연약지반에서의 송전철탑기초의 부등침하를 방지하기 위한 구조물로서, 주기초체와 주기초체 사이에 위치하여 기초를 연결하는 연결보로 구성된다. 본 연구에서는 송전용 철탑기초에 작용하는 연결보의 영향을 조사하기 위하여, 전라북도에 위치한 건설현장에서 24회의 모형재하시험을 수행하였다. 시험에서는 다양한 하중조건과 연결보 조건이 고려되었으며, 시험결과 수평하중에 의한 연결형 말뚝기초의 발생변위가 철탑에 작용하는 수평하중의 각도에 따라 달라지는 것으로 나타났다. 연결형 기초의 침하는 연결보의 강성이 증가할수록 감소하였으며, 수평지지력은 수평하중이 재하되는 철탑의 높이가 낮을수록 증가하였고, 파괴시점에서의 하중의 크기는 대부분의 경우 하중재하방향에 상관없이 유사한 것으로 나타났다. The differential settlement between the foundations causes the critical damage on the transmission tower constructed in soft ground. Connected-pile foundation for transmission tower structures is an option to prevent the differential settlement. It consists of main foundations and connection beams that are placed between the individual foundations at each corner of tower. In this study, 24 model pile load tests were conducted at a construction site in jeonlabuk-do to investigate the effects of the connection beams on transmission tower foundation. In model tests, various load conditions and connection beam conditions were considered. As the test results, the displacements of connected-pile foundation differed in accordance with load directions. The settlements of connected-pile foundation decreased with the increased stiffness of connection beams, lateral load capacity decreased in accordance with load height, and the lateral load capacity on the failure criteria was similar regardless of load direction.

Design on Elevate Mechanism of Large-Scale Multi-Stage Direct-Acting Hydraulic Hoist

For the requirements of volume of cage, load and lifting height, Elevate mechanism of large-scale multi-stage direct-acting hydraulic hoist are adopted when construction hoist lifts material and staff in high-rise construction. Multi-stage expansion of hydraulic cylinder can cause towing oil pipe frequently. Friction and wear between oil pipe and framework is appeared, and oil pipe bursting is occurred. It directly influences both the constructing progress and safety operation. With the ingenious design of hydraulic cylinder and pipe connecting mode, oil pipe towing is avoided telescoping hydraulic cylinder. It provides a new way in other connecting mode of hydraulic system.

Thermal Efficiency of LPG and PNG-fired burners: Experimental and numerical studies

In the present work, the thermal efficiency of a conventional domestic burner is studied both experimentally and numerically for liquefied petroleum gas (LPG) and piped natural gas (PNG) fuels. Three-dimensional computational fluid dynamic (CFD) modeling of the steady-state flow, combustion and heat transfer to the vessel is reported for the first time in such burners. Based on the insights from the CFD model concerning the flow and heat transfer, design modifications in the form of a circular insert and a radiant sheet are proposed which are observed to increase thermal efficiency for LPG. For PNG, predictions showed that loading height was a much more important factor affecting efficiency than these design modifications and an optimal loading height could be identified. Experiments confirm these trends by showing an improvement in burner thermal efficiency of 2.5% for LPG with the modified design, and 10% for PNG with the optimal loading height, demonstrating that the CFD modeling approach developed in the present work is a useful tool to study domestic burners.

Loading Height on Reinforced Brick Masonry Wall's Failure Mode and Seismic Performance with Finite Element Analysis Method

Loading height is a key factor that affects brick masonry wall specimens failure mode and seismic performance. To explore reinforced brick masonry walls failure pattern and seismic performance in different loading height, reinforced brick masonry wall MARC finite element model with 1.44 aspect ratio is set up to analyze its failure mode and seismic performance at constant vertical stress and different loading height. Results are as follows: bending failure happens more easily at higher loading height and shear failure happens more easily at lower loading height; wall specimen shows better deformation ability, elastic and plastic energy dissipation capacity but lower ultimate bearing capacity at higher loading height.

Different Force Conditions on Nonlinear Finite Element Analysis of Small Concrete Hollow Block Wall with Failure Modes of Influence

This paper mainly studies small hollow concrete block wall sets a certain level of reinforcement, vertical bar, core column and high aspect ratio, vertical and horizontal load, changes in load point height wall by shear form and bending failure pattern changes and shear capacity and flexural capacity. Nonlinear analysis simulation using ANSYS finite element analysis software of the specimen, mainly analysis and predict the failure modes of the different loading conditions wall. Obtained by calculating the failure pattern of the specimen, the load-displacement curve, the various stages of the load-displacement values and calculated the relative deformation and ductility factor of the wall under various loading height. Comparative analysis of the load-displacement curve variation of the shear failure and bending failure form, draw the conclusion that bending failure energy consumption better performance.

Analytical solutions attempt for lateral torsional buckling of doubly symmetric web-tapered I-beams

The elastic lateral torsional buckling behavior of doubly symmetric web tapered thin-walled beams is investigated in this work. For the purpose, a non-linear model is developed in large torsion context according to a new kinematics proposed model. Firstly, the elastic equilibrium governing equations are carried out from the stationary condition. Secondly, the Ritz’s method is deployed in order to derive the algebraic equilibrium equations. From this system, an analytical formula is proposed for the lateral buckling strength of web tapered beams in function of the classical stiffness terms, the load height position and the tapering parameter. The proposed formula is simple and gives accurate results when compared to finite element simulations. For this aim some numerical examples are considered in the validation process.

Optimisation of shock absorber process parameters using failure mode and effect analysis and genetic algorithm

The various process parameters affecting the quality characteristics of the shock absorber during the process were identified using the Ishikawa diagram and by failure mode and effect analysis. The identified process parameters are welding process parameters (squeeze, heat control, wheel speed, and air pressure), damper sealing process parameters (load, hydraulic pressure, air pressure, and fixture height), washing process parameters (total alkalinity, temperature, pH value of rinsing water, and timing), and painting process parameters (flowability, coating thickness, pointage, and temperature). In this paper, the process parameters, namely, painting and washing process parameters, are optimized by Taguchi method. Though the defects are reasonably minimized by Taguchi method, in order to achieve zero defects during the processes, genetic algorithm technique is applied on the optimized parameters obtained by Taguchi method.

Influence of operational parameters over biomass growth and decay kinetic constants on membrane bioreactors

ABSTRACT In this study, activated sludge from two experimental full-scale membrane bioreactor (MBR) systems (microfiltration and ultrafiltration) working in parallel has been used to determine YH and bH in a batch respirometer. Both systems were equipped with a pre-denitrification stage and followed the same configuration: anoxic bioreactor, aerobic bioreactor and MBR. Nowadays, describing a conventional or MBR biological process cannot be understood without determining the values of several bio-kinetic parameters describing biomass growth and decay. The aim of this study is to evaluate the influence of several operational parameters related to MBR systems such as sludge retention time (SRT), hydraulic retention time, organic load, sludge temperature and aerobic bioreactor height over the heterotrophic decay coefficient (bH ) and the heterotrophic yield (YH ), whose values ranged from 0.0088 to 0.31 d−1 and from 0.40 to 0.88 mgCOD/mgCOD, respectively. Average sludge temperature and SRT have statistically ...

New airborne retrieval approach for trade wind cumulus properties under overlying cirrus

A new retrieval method is presented to derive the optical thickness τ and effective droplet radius reff of shallow cumulus in the presence of overlying thin cirrus. This new approach allows for a retrieval without a priori knowledge of the microphysical and optical properties of the overlying cirrus. The retrieval is applied to helicopter‐borne solar spectral reflectivity measurements gathered by the Spectral Modular Airborne Radiation measurements sysTem (SMART‐HELIOS) above trade wind cumuli near Barbados. Collocated microphysical cumulus properties (liquid water content, effective droplet radius, droplet number concentration) were measured by in situ instruments installed on the Airborne Cloud Turbulence Observation System (ACTOS). Cloud inhomogeneities lead to an underestimation of retrieved τ of up to 114%, while reff is biased by up to 27%. Moreover, misrepresentation of the overlying cirrus may cause an overestimation of the classically retrieved cumulus reff of up to 50% and an underestimation of τof up to 6%. The new retrieval, effectively correcting for the influence of overlying cirrus, enables reliable estimates of τ of the cumuli for optically thin, overcast cirrus conditions and reduces the retrieval error for reff of the cumuli by almost 50%. Agreement between in situ measured and retrieved reff is in the range of ±1 μm. The retrieval can also reproduce the wide range of in situ measured mean reff (7–18 μm), which is a result of different aerosol load and cloud top heights on the different flight days. The observed τ ranges between 5 and 36.

Influence of boundary conditions and geometric imperfections on lateral–torsional buckling resistance of a pultruded FRP I-beam by FEA

Presented are results from geometric non-linear finite element analyses to examine the Lateral Torsional Buckling (LTB) resistance of a Pultruded Fibre Reinforced Polymer (FRP) I-beam when initial geometric imperfections associated with the LTB mode shape are introduced. A data reduction method is proposed to define the limiting buckling load and the method is used to present strength results for a range of beam slendernesses and geometric imperfections. Prior to reporting on these non-linear analyses, Eigenvalue FE analyses are used to establish the influence on resistance of changing load height or displacement boundary conditions. By comparing predictions for the beam with either FRP or steel elastic constants it is found that the former has a relatively larger effect on buckling strength with changes in load height and end warping fixity. The developed finite element modelling methodology will enable parametric studies to be performed for the development of closed form formulae that will be reliable for the design of FRP beams against LTB failure.