Effects Of Different Loads Research Articles

A comprehensive study on the mechanical properties of Yb2SiO5 as a potential environmental barrier coating

Yb2SiO5 is a promising damage tolerant material to be used as an environmental barrier coating (EBC) for silicon-based ceramic substrates. However limited research is available on its mechanical properties, thus hindering the detailed evaluation of its performance as a possible EBC candidate. In this work, dense Yb2SiO5 is synthesized from Yb2O3 and SiO2 and sintered at 1580 °C. The mechanical properties of the material, including Young's modulus, Vickers hardness and fracture toughness are comprehensively studied to better understand the reliability of Yb2SiO5 as an EBC. Yb2SiO5 has a low Young's modulus of 119 GPa leading to low thermal stresses when deposited on a SiC/SiC substrate. It also has a low hardness value of 6.4 GPa, but a comparatively high fracture toughness value of 1.97 GPa. The effect of different loads on hardness was also investigated and it was noted that Yb2SiO5 exhibits reverse indentation size effect (ISE). This suggests that Yb2SiO5 undergoes relaxation when loaded. These promising results show that Yb2SiO5 could be used as a potential candidate for EBC applications.

The immediate effect of different loads does not alter muscle co-activation of the upper limb in young adults with dyskinetic cerebral palsy.

There is insufficient information on muscle co-activation in the upper limbs to help healthcare providers develop treatment programs for patients with dyskinetic cerebral palsy (DCP). Is the degree of muscle co-activation greater in adults with DCP than in healthy individuals? Does the use of different arm weights modify co-contraction in individuals with PCD? Fourteen healthy individuals (control group [CG]) and 14 individuals with DCP (dyskinetic group [DG]) participated in the study. The degree of muscle co-activation of the dominant limb during drinking from a mug was compared between the two groups. The task was divided into a going, adjusting, and returning phase. In the DG, an analysis was also performed on using an arm weight during the functional task. The loads corresponded to 10, 20, and 30 % of maximum isometric muscle strength measured in each participant. In comparing the two groups, the DG exhibited a greater muscle co-activation in the shoulder and elbow muscles during the going phase, the shoulder, elbow, and wrist during the adjusting phase; and the elbow during the returning phase. The DG also showed a greater mean index of curvature (MIC), time to perform the movement phases, and lesser mean velocity (Vm) to drinking. In analyzing the DG's arm weight, no effect on co-activation, MIC, time to perform the movement phases, and Vm to drinking were found with the loads tested (p > 0.05). Muscle co-activation is increased in adults with DCP in comparison to healthy individuals. Moreover, arm weight during the functional activity of drinking from a mug did not alter co-activation, although an immediate effect was expected.

Influence of Shear Wall on Seismic Response of a Structure

Abstract: Structural analysis is the science of determining the effects of different loads on structures. Structural stability and stiffness are a main concern in any high-rise structures. Shear walls are structural members that are mainly responsible for resisting lateral loads predominant on structures. They are mainly responsible to increase the stiffness, reduce story drift and displacement. In order to have a comprehensive understanding about the contribution of shear wall, following research is carried out. This research involves comparing two G+16 structures; one without a shear wall and one with it. The structure has 4 bays of 3m each along X direction and Z direction. In this, we will see how shear wall resists lateral sway and reduces story drift and increases stiffness. As the height increases, the shear wall absorbs more lateral load than the frame. The software to be used for analysis is STAADPro. Keywords: STAADPro, Stiffness, storey displacement, storey drift.

Assessment of load and generation modelling on the quasi-static analysis of distribution networks

Quasi-static analysis of power systems can be performed by means of timeseries-based and probability density function-based models. In this paper, the effect of different load and generation modelling approaches on the quasi-static analysis of distribution networks is investigated. Different simplified load and distributed renewable energy sources generation timeseries-based models are considered as well as probabilistic analysis. Moreover, a more sophisticated approach based on cluster analysis is introduced to identify harmonized sets of representative load and generation patterns. To determine the optimum number of clusters, a three-step methodology is proposed. The examined cases include the quasi-static analysis of distribution networks for different operational conditions to identify the simplified modelling approaches that can efficiently predict the network voltages and losses. Finally, the computational efficiency by using the simplified models is evaluated in temperature-dependent power flow analysis of distribution networks.

Influence of external loads to wind turbine tower

One of the most important parts of a wind turbine is a tower. There are various designs of the wind turbine towers, and they are most often made of steel pipes, lattice towers or concrete towers. In order to increase energy density to meet the growing electricity needs, larger wind turbine projects have been developed. Larger wind turbine towers can generate more electricity, but such large sizes also create higher costs in terms of development and maintenance. This research sets up a model of a wind turbine tower, where the load to the tower is calculated by its relation to the wind velocity. Analytical approach coupled with a finite element method (FEM) is used to analyse the distribution of tower stresses under these loads. The fatigue analysis of the column is performed using the load from its own weight, the weight of the housing and the distribution of the wind velocity. The effects of different loads are also compared. The results show that the main loads of the tower are the wind force acting on the area of ??rotation of the wind turbine blades and the moment caused by the uneven wind velocity. Construction is modelled using SolidWorks modelling package, where the analysis was performed using FEM in ANSYS software. As a result of the analysis, the stress distribution in the support was determined and compared with analytical calculations.

Natural rubber and copper alumina nanocomposite‐based flexible elastomer‐inorganic hybrid systems

AbstractThis work investigates the effect of different loading of copper alumina nanoparticles (Cu‐Al2O3) on the processing characteristics, crystalline, morphological, mechanical, and thermal properties of natural rubber (NR). The effective reinforcement of Cu‐Al2O3 nanoparticles into NR was carried out using a simple and efficient two roll mill mixing technique and the structural changes were systematically analyzed by Fourier transform infrared (FTIR), X‐ray diffraction (XRD), scanning electron microscope (SEM), high‐resolution transmission electron microscope (HR‐TEM), differential scanning calorimetry, and thermogravimetric analysis. The FTIR and XRD of NR/Cu‐Al2O3 showed the characteristic absorption bands and the crystalline peaks of Cu‐Al2O3 in the prepared composites. SEM and HR‐TEM showed the uniform distribution of nano Cu‐Al2O3 in the NR matrix. The processing time of the nanocomposites was significantly decreased with the addition of metal oxide nanoparticles, which indicated the reduction in the cost of the fabrication of elastomer product using Cu‐Al2O3 nanoparticles. Mechanical properties such as modulus, tensile strength, hardness, heat build‐up, glass transition temperature, tear properties, abrasion, and thermal stability were greatly enhanced by the reinforcement of Cu‐Al2O3 into the NR matrix. The swelling behavior of composite with respect to different loading of nano‐filler was also investigated in various aromatic solvents. The addition of nanoparticles reduces the solvent uptake of the composite and the maximum solvent resistance was noted for the composite with 5 phr loading.

Dynamic Analysis of Fatigue Life Prediction on the Shafts of a Modern Cassava Peeling Machine for Safe and Economic Use

The durability of a machine structure is based on its mechanical performance through its entire service life. To avoid structural failures in machines, it is a standard design practice that machines be analyzed based on the types of loading (static and fatigue) associated with it in order to design safe and dependable machine structures. These types of analyses are performed with the purpose of estimating the behavior of the mechanical parts under specific operational conditions. The aim of this research is to investigate the effect of different loading to the maximum load on the redesigned shafts of an existing cassava peeling machine capable of peeling at least one (10) tons of cassava tubers with different weight, size or shape per day to ascertain the effects on the bending moment, shear force, deflection angle, shear stress and bending stress, and evaluate if there is need to reduce or increase the thickness of the shafts to a standard considered to be safe and economical. The three shafts of the cassava peeling machine have been carefully analyzed to check for their fatigue life under different loading conditions. From the analysis, with stress values of 48.640MPa, 49.1289MPa, 3.06089MPa and shaft diameter values of 34.6799mm, 34.7955mm, 13.7941mm evaluated from the reduced stress diagrams and ideal diameter diagrams for abrasive cylinder shaft, peeling cylinder shaft, and retainer shaft respectively, gave positive results because none of stress values were greater than reduced stresses (calculated stress value from Tresca’s theory) on the respective shafts. Therefore, a standard steel shaft of 35mm diameter is appropriate for manufacturing of the machine and also safe and economical.

An Investigation Into High-Voltage Spiral Generators Utilizing Thyristor Input Switches

High-voltage nanosecond pulses are widely used in scientific research, but their wider adoption in industry requires compact, cost-effective, and easy to use generators to be developed. This article presents the modeling and experimental investigations into one method of producing such pulses-a spiral generator with a solid-state-thyristor-based input switch. It includes how the pulses are formed within the spiral, why a high-speed input switch is required, and how the geometry of the spiral dictates its output characteristics and the effects of different loads. Using thyristors, often connected in series to increase the operating voltage of the spiral, enables the spiral generators to have low jitter, high repetition rate, and long lifetime. Modeling of the circuit used a combination of telegraph equations to account for the wave propagation along the spiral and a lumped circuit exchanging charge between the spiral and the input switch and load. The model is verified by the detailed experimental results with the relative error being <; 10% in most cases. The output voltage pulse was often observed to have an initial peak of much lower magnitude than the subsequent peak(s)-which can only be fully explained by considering wave propagation effects. Lower input switch inductance, shorter switching time, larger mean diameter of the spiral, and increasing the width of the copper tape that makes up the spiral can all increase the voltage multiplication efficiency. Although increasing the number of turns that makes up the spiral can increase the output voltage, it can also lower the multiplication efficiency. By understanding the effects of different geometries, the spiral can be optimized to drive different loads-three applications of such spiral generators are then presented-pulses with 10 kV amplitude and 10 kHz repetition rate for driving dielectric barrier discharge plasma, pulses with amplitude of 10 kV and 10 kV/ns rising rate for triggering of advanced solid-state switches, and pulses with -50 kV amplitude and 50 ns rising time for triggering high-current gas switches through field distortion.

Effect of different loads on wear mechanisms of polyether-ether-ketone in normal saline and debris-isolating method

Polyether-ether-ketone (PEEK) has been proposed as a biocompatible artificial joint material. Wear particles, generated by friction between artificial joints, lead to bone resorption, aseptic loosening, and ultimately, joint failure. The size and morphology of wear particles contain information of friction and wear. Aim to obtain the wear mechanism of PEEK under different loads, this study separated PEEK debris and investigated the mechanism of wear debris and the relationship between wear mechanism and PEEK-debris morphology. An experiment was carried out with a pin-on-plate testing apparatus under different load conditions, with PEEK sliding against XLPE under saline lubrication. A method of isolating PEEK and XLPE debris from 0.9% normal saline at the same time was investigated by low-speed centrifugation. The morphologies of worn surface and wear debris were obtained based on scanning electron microscopy. The results showed that the maximum friction coefficient and minimum wear loss were 0.115 and 0.223 mg at the load of 50 N. The friction coefficient decreased and the wear loss increased with the load increase. This debris-isolation method can effectively isolate PEEK and XLPE particles larger than 200 nm in diameter. More than 96% wear PEEK particles range from 0.1 µm to 10 μm. Compared with the debris generated under the lower load condition, 0.8% more large wear particles with irregular shapes were found at a load of 150 N. The morphology of wear particles is consistent with the wear mechanism.

Low-Cycle Fatigue-Creep Interaction Behavior of GH4169 Supperalloy

Effects of different loading and uninstalling and safe loading time on the low-cycle fatigue-creep interaction behavior of GH4169 superalloy at 650°C/850MPa have been investigated. The study found that under the safe loading time, with the longer the loading and unistalling time, the fatigue-creep property and life of this alloy were gradually improved. However, under the same loading and uninstalling time, with the extension of the loading time, property of the fatigue-Creep of the alloy was gradually reduced, and its life was gradually shortened. In addition, The fracture failure behavior of the alloy under different conditions was studied in detail. Interestingly, With the extension of the holding time, the fracture failure of the alloy was changed from fatigue damage to creep damage, which makes its fracture mode transition the transgranular fracture into intergranular fracture extension.

Novel Fe/B-ZSM-5 nanocatalyst development for catalytic cracking of plastic to valuable products

The plastic wastes and their long-term stability significantly threaten the environment. In this work, the catalytic cracking of plastic was investigated over the multi-functional zeolite nanocatalysts in a dual-zone fixed bed reactor. The nanocatalysts were synthesized hydrothermally, including boron promoter in the structure, followed by multi-step impregnation of iron promoter. The structural and acidity properties were characterized by FE-SEM, XRD, BET, TG-DTA, NH3-TPD, and FT-IR analyzes. The iron species was uniformly dispersed over the nanocatalysts without important framework damage. The nanocatalysts had high surface area, high mesopore volume, and spherical morphology. The effect of different loadings of Fe promoter (0–10 wt.%) was studied. The 5 wt.% Fe promoter resulted in the appropriate textural-acidity conditions. The 5Fe/B-ZSM-5 nanocatalyst had the best product distribution in gasoline range hydrocarbons (C5–12), including high aromatics (76.9%), high isoparaffins (6.2%), and high olefins (11.9%), which contains 95% of the liquid product. The nanocatalyst showed the low coke tendency (3.6%) and the high potential of reusability, including less than 10% drop in the performance through the sequence runs.

Analysis of out-of-round deformation of a dry cylinder liner of a non-road high-pressure common-rail diesel engine based on multi-field coupling

The deformation of cylinder liner directly affects the sealing performance of the friction components in internal combustion engines, resulting in high oil consumption, engine power loss, and high-particulate matter emissions. Previous research works focused more on deformation of the wet vehicular cylinder liners, however, the effects of different loads on the dry liner deformation is not clear yet. A non-road high-pressure common-rail diesel engine was selected as the research object, and a coupled model of the engine was developed based on fluid–solid coupled heat transfer theory. After the accuracy of the model was verified by temperature measurement of the cylinder head and cylinder liner, deformation of the dry cylinder liner was studied. The results show that the axial and radial deformations of the cylinder liner are not uniform under the bolt preload condition. Large deformation occurs at the first liner and fourth liner, with the maximum deformation occurring at the top of fourth liner for 10.14 μm. Under the condition of thermal load, the temperature of cylinder liner exhibits a distribution of three-segments from the top to bottom. The liner deformation is not uniform, and the maximum deformation occurs at the top of the fourth liner for 304 μm. The radial deformations of all four cylinder liners present a symmetrical structure of a “heart” shape with respect to the centerline of the second and third cylinders. The axial deformation of each liner exhibits a “barrel” shape which is convex in the middle and narrow at the two ends.

Smith Ağırlık Makinesi ve Serbest Ağırlık Karşılaştırması: Farklı Yüklerin ve Antrenman Tecrübesinin Set Tekrarları Üzerine Etkisi

Amaç: Araştırmada antrenman tecrübesinin, serbest ağırlık ile Smith ağırlık makinesi uygulamalarının ve farklı yüklerin ardışık setlerdeki kuvvet performansı üzerine etkisi incelenmiştir. Gereç ve Yöntemler: Çalışmaya kuvvet antrenmanına yeni başlayan (yaş= 21,81±2,07 yıl; n=17) ve en az 12 ay antrenman geçmişi olan (yaş=22,89±3,91 yıl; n=16) toplam 33 genç erkek katıldı. Ayrı günlerde serbest ağırlık ve makinede bench press ve squat hareketlerinde bir tekrar maksimum (1-TM) kuvvet ölçümleri gerçekleştirildi. Katılımcılara, belirlenen 1-TM kuvvetin %50-80'nine denk gelen yükte hem serbest ağırlıkla hem de makinede 4 set bench press ve squat press uygulamaları yaptırıldı. Uygulamalar, farklı günlerde sıra takip etmeksizin aynı koşullarda, 3 ila 4 gün ara verilerek yapıldı. Yükün, antrenman tecrübesinin, serbest ağırlık ve makine uygulamalarının setlerdeki performans değişimlerine etkisi 4 faktörlü karışık desenli varyans analiziyle incelendi. Bulgular: Grupların vücut yağ yüzdesi benzerdi (p>0,05), vücut ağırlığı, beden kitle indeksi ve yağsız vücut ağırlığı ortalamaları ise antrenman tecrübesi olan grupta yüksekti (p0,05). Sonuç: Mutlak ve rölatif kuvvet performans farklılıklarına karşın hem serbest ağırlık hem de makine uygulamasında, farklı yükte yapılan set uygulamalarında tekrar sayılarındaki değişim, antrenman tecrübesinden etkilenmemektedir. Bu nedenle ek ağırlıkla direnç egzersizlerine başlayacak tecrübesiz bireylere, öncelikle makine uygulamaları sonrasında da karma uygulamalar önerilebilir.

Biodegradation of Poly (Butylene Succinate) (PBS)/Stearate Modified Magnesium-Aluminium Layered Double Hydroxide Composites under Marine Conditions Prepared via Melt Compounding.

In the present work, polybutylene succinate (PBS)/stearate modified magnesium-aluminium layered double hydroxide (St-Mg-Al LDH) composites were prepared via melt processing and the effect of different loadings of St-Mg-Al LDH on the degradation behaviour of PBS under marine conditions was investigated. The morphological, mechanical and thermal characteristics of the composites were studied using different characterisation techniques. Optical imaging and scanning electron microscopy revealed that the incorporation of St-Mg-Al LDH accelerates the degradation of PBS along with the activity of microorganisms adhered to the composite films. PBS/St-Mg-Al LDH composites are found to have lower thermal degradation temperatures than those of pure PBS. The decrease in thermal stability is correlated with the degradation of PBS due to the catalytic action Mg and Al present in LDH. Tensile and DMA analysis revealed that the addition of St-Mg-Al LDH did not have a significant impact on the mechanical properties of PBS.

Effect of different loads on the friction and wear characteristics of material lubricated with neem oil

The disposal of the mineral oil are the major concern of environment pollution due to their toxicity. Neem oil are the suitable substitutes in the form of bio based lubricant. In this study Neem oil was mixed with the mineral oil in different ratios by volume (5%, 10% and 15%). The friction and wear characteristics of the lubricant was tested on Pin-on disc machine. The effect of load was analysed during the process. The load was applied from 30 N to 90 N at a fixed sliding speed. When the load increases, friction increases and higher friction was attained at 90 N load. The 10% blend produces better results with comparison to other blends. Minimum wear was also obtained at 10% blend.

An improved nonlinear cumulative damage model for strength degradation considering loading sequence

In order to determine the effect of different loads on fatigue damage, a strength degradation model is proposed according to the law of residual strength degradation of metal materials. The model is verified with the strength degradation test data, and the results show that the model can describe the strength degradation process of general metal materials well. Combined with the strength degradation model, an improved equivalent damage model for different loading sequences is proposed. On this basis, a nonlinear fatigue cumulative damage model based on strength degradation is derived. The cumulative damage model is applied to the estimation of fatigue residual life under two-, three-, and four-stage loads to investigate the effects of different loading sequence on fatigue damage under various loading conditions. Combining with experimental data, it is verified that the cumulative damage model can accurately estimate the fatigue life under two-, three-, and four-stage loads.

Study on deformation and failure of slopes under coupled application of water level change and vertical load

As a large number of reservoirs are completed and put into use, slope failure under water level change and external load has caused serious loss of life and property in recent years. The equivalence of deformation and failure processes under different loading combinations is important for establishing an efficient and convenient evaluation method for reservoir slopes. A simulator and a hydraulic loading device were developed to simulate the different loading combinations of the water level change and vertical loading in centrifuge model tests. A series of centrifuge model tests were conducted for this purpose. Based on the results, the coupling mechanism of deformation localization and the failure process were analyzed, and the equivalent damage feature was discussed. The soil slope exhibited a gradual failure process with the loading combination of the water level change and vertical pressure. The coupling effect of deformation localization and the failure process induced the final slope failure. The settlement at the top of the slope was used as a characteristic index because it could comprehensively reflect the effect of different loads and correspond with the process of slope failure. The different loading combinations of the water level differ, but the vertical loading that induced the same settlement at the top of the slope was considered equivalent. As different loading sequences and magnitudes could both be measured, the equivalent impacts are important when studying the coupling effect of loading combinations.

Weighting The Swing: The Mechanical Changes That Emerge When Loads Are Applied To Baseball Bats

Success in baseball batting relies on a union of swing power and accuracy. Off the field, training commonly employs weighted loads replicating hitting mechanics. On the field, immediately prior to a plate appearance, batters sometimes place a weighted ring on the bat to warm up their swing. Although common, these traditional training methods lack investigation. PURPOSE: To observe differences of baseball swing characteristics in response to applied bat resistance. METHODS: We tested 14 NCAA baseball athletes using Proteus technology (Proteus Motion, USA). Participants completed 5 sets of 6 swings at increasing loads of magnetic resistance. Each set increased in weight by 2 lbs, ranging from 1-9 lbs. Measurements computed by Proteus were peak power, peak force development rate (PFDR), braking, consistency, endurance, velocity, and range of motion (ROM). Paired-samples t-tests compared swing characteristics of the 1 lb resistance to the mean of 3, 5, 7, and 9 lb. MANOVA with repeated measures observed the differences of swing variables in response to resistance increases. Linear regression tested the effect of different loads on performance parameters. RESULTS: The 1 lb resistance differed from the mean resistance in peak power (p<0.001), PFDR (p<0.001), braking (p<0.001), ROM (p=0.017), and velocity (p=0.063), but not in consistency (p=0.110) or endurance (p=0.375). The mean values of consistency (p=0.985) and endurance (p=0.530) could not predict outcomes for 1 lb performance, but did predict ROM (p=0.002) and braking, power, PFDR, and velocity (p<0.001). As resistance levels increased, there were significant differences in swing power (F=317.297, p<0.001), PFDR (F=141.797, p<0.001), braking (F=91.011, p<0.001), ROM (F=6.067, p=0.013), and velocity (F=2.5122, p=0.039), but not measurements of consistency (F=0.911, p=0.480) or endurance (F=2.156, p=0.070). CONCLUSIONS: As bat resistance increased, players made acute responses that compromised recruitment characteristics (consistency and endurance). Training and warm-up techniques that employ loaded swings may alter mechanics accordingly.

Sliding Modes Control for Heat Transfer in Geodesic Domes

The analysis and modeling of unconventional thermal zones is a first step for the inclusion of low-cost spaces and for the assessment of the environmental impact among areas of human use in warm climates. In this paper, the heat transfer in a geodesic dome located at the University of Magdalena (Colombia) is modeled and simulated. The simulator is calibrated against experimental measurements and used to study the effect of different loads which are regulated by a controller in sliding modes explicitly designed for this case. The closed-loop system is used together with ASHRAE Standard 55 to characterize comfort conditions within the dome and the effect on the overall thermal sensation with increasing the number of occupants.

Highly selective and stable Zn\u2013Fe/ZSM-5 catalyst for aromatization of propane

Light alkane aromatization for aromatic compound production, used in petrochemical industries is an attractive area of research. The effect of second metal co-impregnation was investigated in stabilizing zinc on ZSM-5 in aromatization of propane. HZSM-5 was modified with zinc and iron metal by co wet-impregnation and characterized using XRF, XRD, BET, N2-adsorption, FTIR, FTIR-Pyridine, SEM, TEM, H2-TPR and XPS. The effect of different loadings of Iron on Zn/ZSM-5 was investigated on acidity, aromatic yield, product distribution and aromatization performance. Performance test was conducted in a fixed bed reactor at 540 °C, one atmosphere. GHSV of 1200 mL/g-h. Co-impregnation of Zn with Fe improved the catalytic activity and aromatic yield for 10 h time on stream as compared to parent HZSM-5 and Zn/ZSM-5 of very low aromatic yield and propane conversion. Impregnation of Zn as the dehydrogenating metal on HZSM-5 steadily increased aromatic yield from 5% on HZSM-5 to 25% and was steadily dropped to 20% after 10 h TOS. The co-impregnation of iron of 1–3 wt% loading as the second metal for zinc stability with 2 wt% Zn on ZSM-5 improved propane conversion and aromatic yield to 55% for the 10 h TOS. This further enhanced aromatic product distribution and minimized light gases.