Performance of Reinforced Concrete Beam with Polystyrene Blocks at Various Regions

Lightweight materials, such as polystyrene, can be embedded in reinforced concrete (RC) beams to reduce its weight. However, this may, to some extent, affect the performance of the structure. This research investigates the behaviour of the lightweight beams under load and determines the best position of polystyrene blocks in beams. Nine specimens with a size of 175 mm x 300 mm x 1600 mm were tested under four-point load test. The number and position of polystyrene blocks in the beams were varied. The specimens were evaluated for effectiveness in terms of effective strength to weight ratio (s-w ratio). The lightweight beam was effective when the polystyrene blocks were placed at the neutral and tensile region, offering an s-w ratio of greater than 1. The beam lost 3.8% strength with 8.4% reduction of weight

Utilization of Oil Palm Empty Fruit Bunch in Cement Bricks

Oil palm empty fruit bunch (EFB) is a biomass waste abundantly produced by the oil palm industry in Malaysia. To minimize the environmental impacts, it needs to be properly disposed of or being rapidly consumed as a raw material of another industry. This study investigated the feasibility of substituting EFB in cement bricks, which is in high demand by the construction industry. A total of 120 specimens having the cement-to-sand (c/s) ratios of 1:2.5 and 1:3 were produced in the laboratory. EFB fibre was used to replace 10% to 25% of sand in the mix by volume. The specimens were tested for the compressive strength, density and water absorption after 28 days of casting. For the mix of 1:2.5 c/s ratio, 25% EFB content reduced 22% of density, decreased 59% of compressive strength and increased 43% of water absorption capacity of normal cement brick. This was mainly attributed to the porous cellular structure of EFB fibre that created a large volume of voids in the mix. Based on the feasibility evaluation, EFB fibre can only replace up to 15% and 10% of sand in the mixes of 1:2.5 and 1:3 c/s ratios respectively

LEARNING ABOUT CONCRETE-FILLED TUBE USING CHATGPT

ChatGPT is an artificial intelligence that can understand context and respond appropriately. It could be used for research on a topic. However, ChatGPT does not always provide accurate information. Its performance has not been tested in engineering fields. In this study, ChatGPT was consulted about concrete-filled tubes (CFT), which is a structural element primarily subjected to axial load. Fifty-eight questions were posted to ChatGPT. ChatGPT’s responses (370 sentences) were evaluated. ChatGPT generated plagiarism-free statements, with only a 12% Turnitin similarity index. 78.6% of ChatGPT’s sentences were long and complex. Thus, Hemingway Editor gave them a Grade 14 for poor readability. The information given by ChatGPT can be classified as correct, erroneous, contradictory, and unverified. ChatGPT could be used as a research tool, but with limitations. It can explain the basic concepts of CFT but also provide inaccurate and contradictory information. A researcher needs to be cautious while using ChatGPT in research. ChatGPT could be used to test some hypotheses or theories. However, the quality of the output is dependent on the user’s critical inputs and an in-depth conversation with ChatGPT

CONCRETE-FILLED TUBULAR COLUMN MADE OF VARIOUS TYPES OF MATERIAL

Concrete-filled tubes (CFT) are gaining popularity due to their excellent performance under compression. Various materials have been used to produce CFTs. Their behaviour varied significantly due to the properties of the materials. In this study, numerous articles related to CFT were reviewed. The effects of carbon steel, stainless steel, fibre-reinforced polymers (FRP), plastic materials, and various kinds of concrete on CFT were observed. The fundamental principles governing the behaviour of CFT were then determined. The confinement effect of the tube was the key to the outstanding performance of CFT. CFT performed well when the tube had high compressive strength, elastic modulus, tensile strength, ultimate strain, and corrosion resistance. The concrete with high compressive strength and ultimate strain, as well as low elastic modulus and shrinkage, experienced greater strength enhancement under confinement. Nevertheless, confinement effectiveness was greatly affected by the slenderness ratio. Short CFT subjected primarily to axial loads was preferred

Experimental Study on the Flexural Behavior of Reinforced Polystyrene Blocks in Concrete Beams

A new type of lightweight beam system was recently proposed by embedding polystyrene in beams to improve structural efficiency. This removes the non-performing concrete in the neutral axis and tension region to provide a comparable strength as a solid beam. There are, however, limited studies conducted to investigate the structural behavior of such beams. Therefore, this research presents an experimental investigation to assess the effect of polystyrene shapes in the beams. This involved testing a solid beam and five lightweight beams under flexural load using a four-point load test. The inclusion of polystyrene was estimated to have reduced the self-weight of beams by 8.6% to 11.8% when compared with the solid beam. The results also showed the ellipse polystyrene with a width of 70 mm and height of 50 mm produced the highest effective strength to weight ratio (sw) of 1.12 and performed 12% better than the solid beam. Moreover, the lightweight beams have more weight reduced than the strength, and those with ellipse polystyrene were found to have performed better than circular ones based on first crack load, ultimate load, and effective strength to weight ratio (sw). The beams with ellipse polystyrene allowed better stress distribution and this gave them a higher strength than sphere shape. For industry application, the polystyrene content is recommended to be greater than 10% while the effective strength to weight ratio (sw) of the beam is greater than 1. The successful reduction of the weight without affecting the structural performance has the ability to help in reducing construction costs

Properties of Cement Brick with Partial Replacement of Sand and Cement with Oil Palm Empty Fruit Bunches and Silica Fume

Oil palm empty fruit bunches (EFB) and silica fume (SF) are the by-products of the oil palm plantation and the ferroalloy smelting industries, respectively. Improper disposal of these materials leads to negative implication to the environment. This study was carried out to investigate the potential application of EFB and SF in cement bricks. EFB fibre and SF replaced up to 25% of sand and cement in the mix, respectively, in several groups of specimens that distinguished the normal, EFB-, SF- and EFB-SF-cement bricks. The specimens were tested for the compressive strength, density and water absorption property. The results reveal that SF, at an optimum amount of 10% cement replacement, increased 10% of the strength of the cement brick. EFB fibre reduced the strength and density but increased water absorption property of the cement brick. For application in the construction industry, SF and EFB fibre contents should be kept within 10% and 20% respectively

Experimental Study of RC Hollow Beams with Embedded PVC Pipes

This study investigated the behaviour of reinforced concrete (RC) hollow beams under incremental static loads. Polyvinyl Chloride (PVC) pipes were used to create longitudinal voids in hollow beams. The parameters studied included the size (25 mm, 50 mm and 75 mm diameter) and location (39 mm and 139 mm from beam soffit) of the PVC pipes in the beam. Nine specimens were tested under the four-point load test setup. The loads were progressively increased until the specimens failed. The specimens were analysed based on the failure modes, load-displacement responses and mechanical properties. The hollow beams gave a 2% to 36% lower strength than the solid beams. In terms of the strength per unit concrete, the hollow beams were less efficient than the solid beams. The efficiency ratio of hollow beams ranged from 0.67 to 1.0. For that, none of the proposed hollow beams was recommended

Electromagnetic Wave Theory and Applications

Contains table of contents for Section 3, reports on four research projects and a list of publications.National Aeronautics and Space Administration Grant NAGW-1617National Aeronautics and Space Administration Agreement 958461National Aeronautics and Space Administration Grant NAGW-1272U.S. Army Corp of Engineers Contract DACA39-87-K-0022U.S. Navy - Office of Naval Research Grant N00014-89-J-1107U.S. Navy - Office of Naval Research Grant N00014-92-J-1616Digital Equipment CorporationJoint Services Electronics Program Contract DAAL03-92-C-0001U.S. Navy - Office of Naval Research Grant N00014-90-J-1002U.S. Navy - Office of Naval Research Grant N00014-89-J-1019U.S. Department of Transportation Agreement DTRS-57-88-C-00078TTD13U.S. Department of Transportation Agreement DTRS-57-88-C-00078TTD30U.S. Department of Transportation Agreement DTRS-57-92-C-00054TTD1DARPA/Consortium for Superconducting Electronics Contract MDA972-90-C-0021National Science Foundation Fellowship MIP 88-5876

Global burden of 369 diseases and injuries in 204 countries and territories, 1990–2019: a systematic analysis for the Global Burden of Disease Study 2019

Background: In an era of shifting global agendas and expanded emphasis on non-communicable diseases and injuries along with communicable diseases, sound evidence on trends by cause at the national level is essential. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) provides a systematic scientific assessment of published, publicly available, and contributed data on incidence, prevalence, and mortality for a mutually exclusive and collectively exhaustive list of diseases and injuries. Methods: GBD estimates incidence, prevalence, mortality, years of life lost (YLLs), years lived with disability (YLDs), and disability-adjusted life-years (DALYs) due to 369 diseases and injuries, for two sexes, and for 204 countries and territories. Input data were extracted from censuses, household surveys, civil registration and vital statistics, disease registries, health service use, air pollution monitors, satellite imaging, disease notifications, and other sources. Cause-specific death rates and cause fractions were calculated using the Cause of Death Ensemble model and spatiotemporal Gaussian process regression. Cause-specific deaths were adjusted to match the total all-cause deaths calculated as part of the GBD population, fertility, and mortality estimates. Deaths were multiplied by standard life expectancy at each age to calculate YLLs. A Bayesian meta-regression modelling tool, DisMod-MR 2.1, was used to ensure consistency between incidence, prevalence, remission, excess mortality, and cause-specific mortality for most causes. Prevalence estimates were multiplied by disability weights for mutually exclusive sequelae of diseases and injuries to calculate YLDs. We considered results in the context of the Socio-demographic Index (SDI), a composite indicator of income per capita, years of schooling, and fertility rate in females younger than 25 years. Uncertainty intervals (UIs) were generated for every metric using the 25th and 975th ordered 1000 draw values of the posterior distribution. Findings: Global health has steadily improved over the past 30 years as measured by age-standardised DALY rates. After taking into account population growth and ageing, the absolute number of DALYs has remained stable. Since 2010, the pace of decline in global age-standardised DALY rates has accelerated in age groups younger than 50 years compared with the 1990–2010 time period, with the greatest annualised rate of decline occurring in the 0–9-year age group. Six infectious diseases were among the top ten causes of DALYs in children younger than 10 years in 2019: lower respiratory infections (ranked second), diarrhoeal diseases (third), malaria (fifth), meningitis (sixth), whooping cough (ninth), and sexually transmitted infections (which, in this age group, is fully accounted for by congenital syphilis; ranked tenth). In adolescents aged 10–24 years, three injury causes were among the top causes of DALYs: road injuries (ranked first), self-harm (third), and interpersonal violence (fifth). Five of the causes that were in the top ten for ages 10–24 years were also in the top ten in the 25–49-year age group: road injuries (ranked first), HIV/AIDS (second), low back pain (fourth), headache disorders (fifth), and depressive disorders (sixth). In 2019, ischaemic heart disease and stroke were the top-ranked causes of DALYs in both the 50–74-year and 75-years-and-older age groups. Since 1990, there has been a marked shift towards a greater proportion of burden due to YLDs from non-communicable diseases and injuries. In 2019, there were 11 countries where non-communicable disease and injury YLDs constituted more than half of all disease burden. Decreases in age-standardised DALY rates have accelerated over the past decade in countries at the lower end of the SDI range, while improvements have started to stagnate or even reverse in countries with higher SDI. Interpretation: As disability becomes an increasingly large component of disease burden and a larger component of health expenditure, greater research and developm nt investment is needed to identify new, more effective intervention strategies. With a rapidly ageing global population, the demands on health services to deal with disabling outcomes, which increase with age, will require policy makers to anticipate these changes. The mix of universal and more geographically specific influences on health reinforces the need for regular reporting on population health in detail and by underlying cause to help decision makers to identify success stories of disease control to emulate, as well as opportunities to improve. Funding: Bill & Melinda Gates Foundation. © 2020 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 licens