Effect Of Material Quality Research Articles

Effect of material quality on cemented sand and gravel (CSG) dam slope design of Cibeet

The construction of the Cibeet Dam is crucial to mitigate downstream flooding in the Citarum River. Initially planned as an embankment dam with a 1:3.50 upstream slope, a 1:30 downstream slope, and a height of 47 meters, challenges arose due to foundation and earthquake considerations. The excessive requirement of embankment material at the dam site, which was insufficiently available, prompted the exploration of a more resource-efficient alternative. Consequently, a slimmer type of dam, specifically a Cemented Sand and Gravel (CSG) dam, was deemed necessary. The CSG dam, designed with minimal cement (80 kg/m3) and a mixture of sand and gravel (105.5 kg/m3), boasts a more upright slope, reducing material demand. This research examines the impact of material quality on the CSG dam slope. The finite element method assesses the dam’s stability using dynamic seismic forces. To achieve a stable dam slope design with existing materials, an extensive analysis was conducted on various slopes upstream and downstream, ranging from 1:0.70 to 1:1.20. The results indicate that a slope of 1:1.10 with a cement compound of 105.5 kg/m3 offers optimal stability. Implementing the CSG Dam effectively minimizes material requirements, mitigating the need for excessive exploration of material supplies.

Mechanochemically-assisted synthesis of 3D, 2D and quasi 2D lead halide perovskites for supercapacitor applications

A mechanochemically synthesized family of lead halide perovskites was utilized to fabricate electrodes for electrolyte-based supercapacitors. The effect of material quality and dimensionality of the perovskite structure on the device performance and stability was thoroughly discussed.

The Effect of Material Quality on Buildings Moderately and Heavily Damaged by the Kahramanmaraş Earthquakes

On 6 February 2023, two major earthquakes occurred in the Turkish province of Kahramanmaraş. The first earthquake with a magnitude of Mw 7.7 occurred in the center of Kahramanmaras, while the second earthquake with a magnitude of Mw 7.5 occurred in the region of Elbistan. These earthquakes caused heavy damage and loss of life in the affected regions. In particular, the Elbistan region experienced both earthquakes with great severity. Following the earthquakes, damage analyses were carried out on the earthquake-affected structures in this region. In the region, 1045 buildings were destroyed, 2640 buildings were heavily damaged, and 463 buildings were moderately damaged by the earthquakes. In this study, the relation between the material quality and the damage status of the affected buildings in the Elbistan region was investigated. A total of 20 buildings with heavy and moderate damage, built both before and after the year 2000, were selected for analysis. Samples were taken from these buildings, and the compressive strength values of the samples were obtained. Further, in situ experiments featuring the Schmidt and UPV tests were performed in the buildings. The results found that the buildings lacked adequate concrete strength. In particular, the post-2000 structures recorded concrete strength values below the established standard. This study proves the necessity of following established regulations in the design and construction of buildings in earthquake-prone zones, especially with respect to the construction materials used.

Performance analysis of narrow-bandgap interband cascade thermophotovoltaic cells

We present the detailed characterization and performance analysis of two sets of four interband cascade thermophotovoltaic devices with InAs/GaSb type-II superlattice (SL) absorbers. The bandgaps of the SL absorbers in the four devices were between 0.22 and 0.25 eV at 300 K. With different numbers of cascade stages and individual absorber thicknesses, we are able to show how possible material quality variations and current mismatch between stages can affect the device performance. Based on the calculated effective quantum efficiency in each stage and experimental results, it is shown that the current mismatch between stages due to the deviation of absorption coefficient from the designed value can be substantial with more stages. On the other hand, the collection efficiency can be much improved with more stages and thin individual absorbers. Also, the carrier lifetime is extracted through measured dark current density to evaluate the material quality. The effects of material quality, current mismatch and collection efficiency on device performance are quantified and a comparison shows that material quality plays the most important role.

Effects of different fermentation and storage conditions on methanol content in Chinese spine grape (Vitis davidii Foex) wine

ABSTRACT The methanol content is an important indicator in determining the quality of wine. The effects of material quality, fermentation conditions and storage containers on the formation of methanol and other substances in winemaking process were studied. The methanol content in spine grape wine was observed to increase as the fermentation temperature increased. Extending maceration time and the increasing addition of pectinase also increased the methanol content. No significant change in methanol content was observed with various yeasts added. The methanol content in wine that is stored in oak barrels was the lowest compared to that in other containers. The optimal conditions to control the methanol content in spine grape wine should be as follows: ferment wine with high-quality materials under 25–26°C for 3–6 d, with a pectinase of 15–20 mg/L and yeast added; and store the wine in oak barrels.

Material quality effects on structural design of rudder horns for bulk carriers and tankers

ABSTRACTThis paper addresses the assessment of the structural integrity of a rudder horn built of different materials and in particular, the material quality effects on the structural design of a typical rudder horn of a conventional Panama-Kamsarmax size ship in relation to IACS requirements. The minimum scantlings of the rudder horn were established and compared for different steels permitted in IACS UR S10. Furthermore, a FEA model of the rudder horn including its most critical part i.e. its connection to the hull structure was developed in order to calculate and compare stress and deflections under the IACS prescribed loading conditions. The findings suggest that the use of higher strength material may reduce substantially the fatigue life of the structure at the critical area of rudder horn to hull connection which may cause the initiation of cracking, with adverse impact to the safety of the ship and its crew.

Modelling of Plastic Culvert and Road Embankment Interaction in 3D

A series of 3D Finite Element simulations was performed to investigate the effect of different factors influencing the distortions undergone by a plastic culvert tube while subject to external loading from a heavy truck. The applied simulation model was verified by full-scale loading tests carried out on a number of actual culvert installation sites. Based on the results of the study, it can be concluded that both installation depth and quality of the material surrounding the culvert have a dominant effect on culvert distortions while the effects of material quality above the culvert and the type of tyre configuration transmitting the wheel load are much less pronounced.

Demonstration of negative differential resistance in GaN/AlN resonant tunneling diodes at room temperature

GaN/AlN resonant tunneling diodes (RTD) were grown by metal-organic chemical vapor deposition (MOCVD) and negative differential resistance with peak-to-valley ratios as high as 2.15 at room temperature was demonstrated. Effect of material quality on RTDs’ performance was investigated by growing RTD structures on AlN, GaN, and lateral epitaxial overgrowth GaN templates. Our results reveal that negative differential resistance characteristics of RTDs are very sensitive to material quality (such as surface roughness) and MOCVD is a suitable technique for III-nitride-based quantum devices.

Seismic performance evaluation of school buildings in Turkey

This study evaluates seismic performance of the school buildings with the selected template designs in Turkey considering nonlinear behavior of reinforced concrete components. Six school buildings with template designs were selected to represent major percentage of school buildings in medium-size cities located in high seismic region of Turkey. Selection of template designed buildings and material properties were based on field investigation on government owned school buildings in several cities in western part of Turkey. Capacity curves of investigated buildings were determined by pushover analyses conducted in two principal directions. The inelastic dynamic characteristics were represented by equivalent single-degree-of-freedom (SDOF) systems and their seismic displacement demands were calculated under selected ground motions. Seismic performance evaluation was carried out in accordance with recently published Turkish Earthquake Code that has similarities with FEMA-356 guidelines. Reasons of building damages in past earthquakes are examined using the results of performance assessment of investigated buildings. The effects of material quality on seismic performance of school buildings were investigated. The detailed examination of capacity curves and performance evaluation identified deficiencies and possible solutions for template designs.

Seismic capacity evaluation of school buildings in Turkey

This study evaluates the seismic capacity of school buildings with the selected template designs constructed per pre-modern code in Turkey, considering non-linear behaviour of reinforced concrete components. Capacity curves of the investigated buildings were determined by pushover analyses conducted in two principal directions. Seismic capacity evaluation was carried out in accordance with the recently published Turkish Earthquake Code (2007) that has similarities with FEMA-356 guidelines. Based on capacity curves of school buildings, it was found that the effect of material quality and detailing on seismic capacity is especially apparent for buildings with no or a limited number of shear walls. Buildings with a certain number of shear walls are less affected by low material quality and detailing, emphasising the importance of shear walls, especially in countries where construction with poor detailing is a common problem. The outcome of the study indicates that the existing school buildings constructed per the pre-modern code far from satisfying the expected performance objectives of the recent code requirements, suggesting that urgent planning and response need to be put in action.

Structural Response of LVR Flexible Pavements at Mn/Road Project

Pavement surface deflection basins provide valuable information for the structural evaluation of flexible pavements. Surface deflection measurements are rapid, inexpensive, and nondestructive and are used frequently as an indicator of pavement structural capability and performance potential. In this study, falling weight deflectometer testing results on the conventional flexible pavements (asphalt concrete surface, granular base/subbase) and aggregate-surface/surface-treated test sections in the low-volume road loop at the Minnesota Road Research Project (Mn/ROAD) were analyzed to evaluate the effect of granular material quality on the pavement structural response. Asphalt concrete (AC) modulus and subgrade ``break-point`` modulus were back-calculated using algorithms previously developed at the University of Illinois. The surface deflections were normalized to the same AC modulus and subgrade modulus. The analyses show a limited effect of granular material quality on the pavement deflection response in the case of conventional flexible pavements. Because of higher granular layer stresses, the granular material quality effects on the pavement surface deflection response of surface-treated/aggregate-surface pavements are significant. Increased AC thickness reduces the effect of granular base quality on the pavement deflection response.

High resolution X-ray diffraction studies of semiconductor superlattices

Recent years have seen the development and application of high resolution X-ray diffraction techniques in order to non-destructively assess the structural and compositional quality of complex epitaxial semiconductor structures. The most widely used technique is double crystal diffraction, which is used to record the complex multipeaked rocking curves associated with current multilayer epitaxial structures. However, effects of material quality on this diffraction data can only be quantified and understood by the application of a versatile theoretical rocking curve simulation package which is capable of simulating the effects of small deviations from the ideal material structure. The use of both theory and experiment to identify and solve growth induced materials problems in semiconductor superlattice structures is demonstrated with a number of examples. In Si 1- x Ge x /Si superlattices grown by molecular beam epitaxy a detailed analysis of the asymmetric broadening of superlattice reflections enables this effect to be directly attributed to a slight drift of 1.25% in the Ge flux during the growth run. In In 1- x Ga x As/InP superlattices grown by MOCVD the exact nature of the growth system improvements necessary to sharpen the layer interfaces are identified and in MBE grown InSb/CdTe superlattices the presence and nature of thin, highly strained interfacial layers is assessed. The limitations of the double crystal system are outlined along with the advantages of moving towards a multiple crystal diffraction system.