Behavior of bonded and unbonded prestressed normal and high strength concrete beams

AbstractThe major disadvantage of using ordinary reinforced concrete (RC) elements is the corrosion of steel, which occurs due to effect of cracks in tension zones. The main advantage of the fully prestressed concrete system is the absence of cracks in the concrete at the nominal service load and therefore better durability will be achieved. Combining the PC system with the use of high strength concrete is a milestone, which will potentially result in a new design approach. The disadvantage of the use of this combination is referred to the reduced ductility of concrete members.This paper presents an experimental program conducted to study the behavior of bonded and unbounded prestressed normal strength (NSC) and high strength concrete (HSC) beams. The program consists of a total of nine beams; two specimens were reinforced with non-prestressed reinforcement, four specimens were reinforced with bonded tendons, and the remaining three specimens were reinforced with unbonded tendons. The overall dimensions of the beams are 160×340×4400-mm. The beams were tested under cyclic loading up to failure to examine its flexural behavior. The main variables in this experimental program are nominal concrete compressive strength (43, 72 and 97MPa), bonded and unbonded tendons and prestressing index (0%, 70% and 100%). Theoretical analysis using rational approach was also carried out to predict the flexural behavior of the specimens. Evaluation of the analytical work is introduced and compared to the results of the experimental work

Application of the Repulsive-Type Magnetic Bearing for Manufacturing Micromass Measurement Balance Equipment

Many applications of the single-axis controlled repulsive-type magnetic bearing have been proposed earlier. However, both passive and active magnetic bearings are employed in most of such systems. In this paper, a new permanent magnet (PM) repulsive-type micromass measurement system is developed. The repulsive forces of the PM section are used effectively to keep the radial direction stable where the electromagnets, control circuits, and peripheral devices needed for controlling the unstable direction are simplified. The configuration, control design, and operating characteristics of the proposed system have been presented

Global burden of 288 causes of death and life expectancy decomposition in 204 countries and territories and 811 subnational locations, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021

Background: Regular, detailed reporting on population health by underlying cause of death is fundamental for public health decision making. Cause-specific estimates of mortality and the subsequent effects on life expectancy worldwide are valuable metrics to gauge progress in reducing mortality rates. These estimates are particularly important following large-scale mortality spikes, such as the COVID-19 pandemic. When systematically analysed, mortality rates and life expectancy allow comparisons of the consequences of causes of death globally and over time, providing a nuanced understanding of the effect of these causes on global populations. Methods: The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 cause-of-death analysis estimated mortality and years of life lost (YLLs) from 288 causes of death by age-sex-location-year in 204 countries and territories and 811 subnational locations for each year from 1990 until 2021. The analysis used 56 604 data sources, including data from vital registration and verbal autopsy as well as surveys, censuses, surveillance systems, and cancer registries, among others. As with previous GBD rounds, cause-specific death rates for most causes were estimated using the Cause of Death Ensemble model—a modelling tool developed for GBD to assess the out-of-sample predictive validity of different statistical models and covariate permutations and combine those results to produce cause-specific mortality estimates—with alternative strategies adapted to model causes with insufficient data, substantial changes in reporting over the study period, or unusual epidemiology. YLLs were computed as the product of the number of deaths for each cause-age-sex-location-year and the standard life expectancy at each age. As part of the modelling process, uncertainty intervals (UIs) were generated using the 2·5th and 97·5th percentiles from a 1000-draw distribution for each metric. We decomposed life expectancy by cause of death, location, and year to show cause-specific effects on life expectancy from 1990 to 2021. We also used the coefficient of variation and the fraction of population affected by 90% of deaths to highlight concentrations of mortality. Findings are reported in counts and age-standardised rates. Methodological improvements for cause-of-death estimates in GBD 2021 include the expansion of under-5-years age group to include four new age groups, enhanced methods to account for stochastic variation of sparse data, and the inclusion of COVID-19 and other pandemic-related mortality—which includes excess mortality associated with the pandemic, excluding COVID-19, lower respiratory infections, measles, malaria, and pertussis. For this analysis, 199 new country-years of vital registration cause-of-death data, 5 country-years of surveillance data, 21 country-years of verbal autopsy data, and 94 country-years of other data types were added to those used in previous GBD rounds. Findings: The leading causes of age-standardised deaths globally were the same in 2019 as they were in 1990; in descending order, these were, ischaemic heart disease, stroke, chronic obstructive pulmonary disease, and lower respiratory infections. In 2021, however, COVID-19 replaced stroke as the second-leading age-standardised cause of death, with 94·0 deaths (95% UI 89·2–100·0) per 100 000 population. The COVID-19 pandemic shifted the rankings of the leading five causes, lowering stroke to the third-leading and chronic obstructive pulmonary disease to the fourth-leading position. In 2021, the highest age-standardised death rates from COVID-19 occurred in sub-Saharan Africa (271·0 deaths [250·1–290·7] per 100 000 population) and Latin America and the Caribbean (195·4 deaths [182·1–211·4] per 100 000 population). The lowest age-standardised death rates from COVID-19 were in the high-income super-region (48·1 deaths [47·4–48·8] per 100 000 population) and southeast Asia, east Asia, and Oceania (23·2 deaths [16·3–37·2] per 100 000 population). Globally, life expectancy steadily improved between 1990 and 2019 for 18 of the 22 investigated causes. Decomposition of global and regional life expectancy showed the positive effect that reductions in deaths from enteric infections, lower respiratory infections, stroke, and neonatal deaths, among others have contributed to improved survival over the study period. However, a net reduction of 1·6 years occurred in global life expectancy between 2019 and 2021, primarily due to increased death rates from COVID-19 and other pandemic-related mortality. Life expectancy was highly variable between super-regions over the study period, with southeast Asia, east Asia, and Oceania gaining 8·3 years (6·7–9·9) overall, while having the smallest reduction in life expectancy due to COVID-19 (0·4 years). The largest reduction in life expectancy due to COVID-19 occurred in Latin America and the Caribbean (3·6 years). Additionally, 53 of the 288 causes of death were highly concentrated in locations with less than 50% of the global population as of 2021, and these causes of death became progressively more concentrated since 1990, when only 44 causes showed this pattern. The concentration phenomenon is discussed heuristically with respect to enteric and lower respiratory infections, malaria, HIV/AIDS, neonatal disorders, tuberculosis, and measles. Interpretation: Long-standing gains in life expectancy and reductions in many of the leading causes of death have been disrupted by the COVID-19 pandemic, the adverse effects of which were spread unevenly among populations. Despite the pandemic, there has been continued progress in combatting several notable causes of death, leading to improved global life expectancy over the study period. Each of the seven GBD super-regions showed an overall improvement from 1990 and 2021, obscuring the negative effect in the years of the pandemic. Additionally, our findings regarding regional variation in causes of death driving increases in life expectancy hold clear policy utility. Analyses of shifting mortality trends reveal that several causes, once widespread globally, are now increasingly concentrated geographically. These changes in mortality concentration, alongside further investigation of changing risks, interventions, and relevant policy, present an important opportunity to deepen our understanding of mortality-reduction strategies. Examining patterns in mortality concentration might reveal areas where successful public health interventions have been implemented. Translating these successes to locations where certain causes of death remain entrenched can inform policies that work to improve life expectancy for people everywhere. Funding: Bill & Melinda Gates Foundation

Egyptian diatomite as high fluid loss squeeze slurry in sealing fractures and

Lost circulation is the most costly mud related drilling problem, and induced fracture. Water slurry of diatomite is used as the high fluid loss squeeze slurry in the treatment of lost circulation and in decreasing fluid loss. Egypt has diatomite deposits, especially in El-Fayuom Depression. Fourteen samples were collected from Qasr El-Sagha at the northern shore of Birket Qarun. Samples were examined to identify the diatom species then subjected to X-ray fluorescence, XRD and grain size distribution tests. A total of 38 species related to 13 diatom genera were identified. Cocconeis, Epithemia and Rhopalodia were the predominant genera. The diatomaceous earth which acts as a filter aid material was tested with different additives; bentonite, lime, finely divided paper, polymer, barite and different concentrations with different types of lost circulation materials (LCM) to form a high fluid loss squeeze slurry. As a result the required time for collecting the filtrate was decreased to be in the range of 50 s to 1 min and 49 s comparing with the international standard which recommended the filtrate should be collected maximum within 2–3 min

A review on the diagnosis infection in cattle of Schistosoma bovis: current status and future prospects Revisão sobre diagnóstico de infecção por Schistosoma bovis em bovinos: estado atual e perspectivas para o futuro

Bovine schistosomiasis, caused by Schistosoma bovis, is a serious veterinary problem in many parts of the worid. The current methods used for the diagnosis of the disease include clinical signs, pathological lesions, parasitological and serological techniques. As clinical signs and parasitological lesions caused by S. bovis are indistinguishable from those induced by other trematode parasites, confirmation of diagnosis by these methods is unreliable. Parasitological techniques used to demonstrate eggs of the parasite in fecal or tissue samples represent the most accurate method for detection of an active S. bovis infection. The tissue of choice for detection of S. bovis infection is the liver because of the visible macroscopic lesion that can be seen in that organ and the rapid detection of the parasite eggs under the microscope using crush smears. The serological techniques used for diagnosis of the disease do not necessarily identify an active infection. In addition, some of the positive reactions are non specific. However, serology is useful to identify previous infection in epidemiologic study. The ELISA has been recentiy validated for the diagnosis of bovine schistosomiasis and will probably replace the other serological tests. The immunoblotting technique has been proven satisfactory to detect antibodies to defined and recombinant schistosome antigen vaccines. Nucleic acid hybridization techniques have been described for the study of schistosome species-specific identification. However, these molecular techniques have not yet revolutionarized diagnosis of schistosomiasis. These techniques will probably serve as the basis for future diagnostic tests.<br>Esquistossomose bovina, causada pelo parasita Schistosoma bovis, é um problema muito sério para a Veterinária em muitas partes do mundo. Os métodos atuais utilizados para o diagnóstico da doença incluem sinais clínicos, lesões patológicas, e técnicas de parasitologia e sorologia. Como os sinais clínicos e as lesões parasitológicas causadas pelo S. bovis são distingüíveis em relação às lesões induzidas por outros trematódeos, a confirmação do diagnóstico por estes métodos é questionável. Técnicas de parasitologia utilizadas para demonstrar ovos do parasita em amostras fecais ou teciduais representam os métodos mais acurados para detecção de uma infecção ativa pelo S. bovis. O tecido de preferência para detecção da infecção causada pelo S. bovis é o fígado devido à visível lesão macroscópica que pode ser vista neste órgão e da rápida detecção dos ovos do parasita usando "crush smears" e visualização microscópica. As técnicas de sorologia utilizadas para o diagnóstico desta doença não identificam necessariamente uma infecção ativa. Adicionalmente, algumas reações positivas não são específicas. Entretanto, sorologia é válida para identificar infecções prévias em um estudo epidemiológico. O teste de ELISA tem sido desenvolvido recentemente para o diagnóstico de equistossomose bovina e provavelmente substituirá os outros testes sorológicos. A técnica de "immunoblotting" tem sido satisfatoriamente aprovada para a detecção de anticorpos e vacinas recombinantes do antígeno do esquistossoma. Técnicas de hibridização do ácido nucleico tem sido descritas para o estudo de identificação de especificidade do schistossoma. Entretanto, estas técnicas moleculares ainda não revolucionaram o diagnóstico da esquistossomose. Provavelmente, estas técnicas ainda serão base para os testes de diagnóstico do futuro

An oral cancer biobank initiative: a platform for multidisciplinary research in a developing country

Identification of diagnostic markers for early detection and development of novel and therapeutic agents for effective patient management are the main motivation for cancer research. Biological specimens from large cohort and case-control studies which are crucial in providing successful research outcomes are often the limiting factor that hinders research efforts, especially in developing countries. Therefore, the Malaysian Oral Cancer Database and Tissue Bank System (MOCDTBS) were established to systematically collect large number of samples with comprehensive sociodemographic, clinicopathological, management strategies, quality of life and associated patient follow-up data to facilitate oral cancer research in Malaysia. The MOCDTBS also promotes sharing among researchers and the development of a multidisciplinary research team. The following article aims to describe the process of setting-up and managing the MOCDTBS. © 2012 Springer Science+Business Media B.V