Failure analysis of a shaft of a car lift system

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Fatigue properties of nanocrystallized surfaces obtained by high energy shot peening

AbstractAn unconventional method of shot peening aimed to generation of a nanograined layer over the surface of specimens has been applied by means of the standard air blast equipment but using peening parameters essentially different from typical ones. Surface nanocrystallization is verified and affirmed through different experimental procedures. Rotating bending fatigue tests are performed to evaluate the effect of this high energy shot peening and the nanocrystallized layer on fatigue life. First series results are available and the other tests are still in progress

Development of a fatigue test machine for high frequency applications

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Microscopic structure of the intestine of beluga (Huso huso) from hatching until ranching to sea

Microscopic structure of intestine of beluga was studied from hatching until releasing to sea. Larvae were fixed in bouin’s solution, dehydrated and embedded in paraffin wax. Sections of 5-7 μm thick were produced and stained according to standard histological techniques: Hematoxylin-Eosin (HαE) and Periodic Acid Schiff (PAS). One day old larvae possessed a primordial intestine, which is lined by a simple columnar ciliated epithelium. At 3 days after hatching, an oblique furrow of the digestive tube wall started to develop on the dorsal- posterior region of the yolk sac and divided the alimentary canal into two differentiated regions: the future stomach and intermediate intestine. At this time spiral valve started to differentiate. Granules of embryonic pigment accumulated in the spiral valve lumen forming the melanin plug. At 7 days after hatching intermediate gut and spiral gut were lined by a columnar ciliated epithelium. The terminal section of the digestive tract was differentiated into a short rectal duct lined with a cuboidal epithelium. The urinary bladder connected with rectum at this time. At 13 days after hatching the number of vacuoles filled with lipid increase in intermediate gut and spiral gut. Between 17-19 days post hatching beluga larvae have a period of mixed nutrition. At 25 days after hatching cells of intermediate gut showed long microvilli. At 36 days after hatching the number of goblet cells increased in spiral gut. At 43 days after hatching several intestine glands were visible in connective tissue of intermediate gut which was lined by a simple columnar ciliated epithelium. Between 57-75 days after hatching the number and size of mucosal folds increased in intestine. This information may be useful to improve rearing efficiency of beluga and the other sturgeons

Prevalence rate of hepatitis B virus in pregnancy: Implications from a systematic review and meta-analysis of studies published from 2000 to 2016

Background: Hepatitis B Virus (HBV) is one of the most serious infectious diseases and represents a major global health issue worldwide. It can be transmitted vertically and horizontally through contact with infected blood or body fluids. More attention to HBV infection in pregnancy is needed due to high risk of chronicity when transmitted to infants during delivery. Objectives: A comprehensive review of the HBV prevalence rate in pregnant females taking into account different geographical areas and socio-economic status is still lacking. This would be of crucial importance for HBV prevention and control programs. As such, this systematic review and meta-analysis was conducted focusing on HBV prevalence rate in pregnant females from different parts of the world. Methods: Different electronic databases, including Embase, PubMed/MEDLINE, Scopus, and ISI/Web of Science were searched from January 1st 2000 to July 31st 2016, using relevant keywords, such as �prevalence� or �seroprevalence� or �epidemiology� and �pregnancy� or �pregnant� or �antenatal� in combination with �hepatitis B virus� or �HBV� with no language restrictions. The study protocol of this systematic review was deposited at the �International Prospective Register of Systematic Reviews� and registered as CRD42016041985. Results: After scrutinizing all the extant scholarly literature from 2000 to 2016, this study found 222 relevant articles. The overall HBV prevalence rate in pregnant females worldwide was estimated using a random-effect model, giving a value of 3 (95 confidence interval or CI 2 - 4). Heterogeneity between studies was significantly high (I2 = 99.9, P < 0.0001). The clinical and epidemiological burden was higher in developing countries. Conclusions: This suggests that despite the recent scientific advancements and the clinical progress that has occurred in anti-viral therapy, HBV still represents a major issue worldwide, especially in underdeveloped countries. The key strategies for preventing transmission from pregnant females to their fetuses are through early birth dose and infant vaccination, as well as by the use of hepatitis B immunoglobulin (HBIG) and the screening and diagnosis of mothers at high risk and the subsequent use of anti-viral agents during pregnancy in order to reduce maternal DNA concentrations down to undetectable concentrations. Health authorities should effectively implement these approaches to better control HBV in pregnancy. © 2018, Hepatitis Monthly

Prevalence rate of hepatitis B virus in pregnancy: Implications from a systematic review and meta-analysis of studies published from 2000 to 2016

Background: Hepatitis B Virus (HBV) is one of the most serious infectious diseases and represents a major global health issue worldwide. It can be transmitted vertically and horizontally through contact with infected blood or body fluids. More attention to HBV infection in pregnancy is needed due to high risk of chronicity when transmitted to infants during delivery. Objectives: A comprehensive review of the HBV prevalence rate in pregnant females taking into account different geographical areas and socio-economic status is still lacking. This would be of crucial importance for HBV prevention and control programs. As such, this systematic review and meta-analysis was conducted focusing on HBV prevalence rate in pregnant females from different parts of the world. Methods: Different electronic databases, including Embase, PubMed/MEDLINE, Scopus, and ISI/Web of Science were searched from January 1st 2000 to July 31st 2016, using relevant keywords, such as �prevalence� or �seroprevalence� or �epidemiology� and �pregnancy� or �pregnant� or �antenatal� in combination with �hepatitis B virus� or �HBV� with no language restrictions. The study protocol of this systematic review was deposited at the �International Prospective Register of Systematic Reviews� and registered as CRD42016041985. Results: After scrutinizing all the extant scholarly literature from 2000 to 2016, this study found 222 relevant articles. The overall HBV prevalence rate in pregnant females worldwide was estimated using a random-effect model, giving a value of 3 (95 confidence interval or CI 2 - 4). Heterogeneity between studies was significantly high (I2 = 99.9, P < 0.0001). The clinical and epidemiological burden was higher in developing countries. Conclusions: This suggests that despite the recent scientific advancements and the clinical progress that has occurred in anti-viral therapy, HBV still represents a major issue worldwide, especially in underdeveloped countries. The key strategies for preventing transmission from pregnant females to their fetuses are through early birth dose and infant vaccination, as well as by the use of hepatitis B immunoglobulin (HBIG) and the screening and diagnosis of mothers at high risk and the subsequent use of anti-viral agents during pregnancy in order to reduce maternal DNA concentrations down to undetectable concentrations. Health authorities should effectively implement these approaches to better control HBV in pregnancy. © 2018, Hepatitis Monthly

Yolk utilization and growth during the early larval life of the Silver Perch, Bidyanus bidyanus (Mitchell, 1838)

The aim of this research was to investigate the yolk sac and oil globule utilization by silver perch (Bidyanus bidyanus) larvae produced from domesticated broodfish. The larvae were kept unfed in the holding tank, sampled, and investigated by image analysis software to determine various characteristics, such as the diameters of ova, water-hardened eggs, yolk-sac, oil globules, and the total length of larvae. The research illustrated that, with the exception of oil globule diameter, all other morphometric parameters were significantly lower (P < 0.05) when compared to the larvae from the wild broodfish. The yolk sac was completely absorbed at 96 h post-hatching (hph) and the oil globule was visible until 240 hph. The larvae exhibited predatory movements and tried to catch rotifer at 4 days post hatching (dph). However, the onset of feeding took place at 5 dph, while 100% of feeding occurred at 6 dph. During the first 96 h (h), larvae grew significantly faster than the next 144 h. Larvae encountered low mortalities (<10%) during the first 96 hph, before increasing significantly in the next 24 h and no unfed larvae survived post 240 h. The results also suggested that the exogenous feed should be available at 96 hph, which is well after the yolk sac is completely depleted. In addition, although most of eggs and larval performance from domesticated broodfish were inferior compared to the wild one, it has larger oil globule that could make longer of its mixed feeding period and therefore could have better in viability

Geometrical optimization for notches based on multi axial fatigue criterion

ABSTRACT. Shape optimization of components subjected to multiaxial fatigue is studied. The application of static optimization algorithms, generally based on Von-Mises stress, is no more applicable in these cases. In this paper an optimizing routine for multiaxial fatigue is developed on the basis of the CAO technique proposed by Mattheck. According to a criterion for fatigue strength estimation of notched specimens made of ductile materials and subjected to mutiaxial fatigue: Liu-Zenner. Abaqus 6.8-1is used as the commercial software to develop finite element simulation and Python 2.4 and Matlab2007 are used as the subroutine programs

MICROSTRUCTURAL CHARACTERIZATION AND FATIGUE BEHAVIOR OF COLD SPRAY COATED ALUMIUM ALLOY

Different sets of Al5052 alloy specimens have been coated by pure Al and Al7075 alloy powder, using low pressure cold spray coating technique. The microstructural evolution of the substrate after coating and the fatigue behavior of the coated structure have been surveyed. In order to obtain the fatigue S-N diagram of each set, as received and coated specimens have been tested at load control condition. The powders size distribution and shape has been studied by scanning electron microscopy (SEM). X- ray diffraction (XRD) has been used to measure the residual stress in both deposited material and the substrate. Grain size measurements are performed by XRD using a portable unit. The results of different characterizing tests have been then discussed to highlight the effects of this emerging surface treatment on the characteristics of the treated material