349 research outputs found
Rheology Of Cement Paste Containning Chemical Admixtures
Understanding the Rheology of cement and water is a not a simple task since, thebehaviour of complicated system varies with time and there is still a great deal of work to bedone before, it is properly understood. In this study, we used a new simple and cheaptechnique to evaluate flow properties of cement paste .This technique is based on dropping aneedle from a constant height. The penetration depth is measured at different circumstances,different w/c ratios, different types of super plasticizer, and different percentage of admixturefor two types of cement types of cements OPC type V (CEMEX) and OPC type I (HELWAN)were considered in this study. Also, effect of retempering on penetration depth were alsoconsidered. Finally effect of variation of needle drop height was also considered. Thepenetration depth technique proved to be effective in monitoring the effect ofsuperplasticizer/cement ratio percentage, effect of time, manual remixing after 30 minutesand needle drop height on the rheological behavior of different types of cement paste, whichfurther proves the effectiveness of this method in evaluation of cement paste Rheology
Effect of Extractive Solvents on Bio – Oil Production From Microalgae via Hydrothermal Liquefaction
Bio–oil from spirulina sp. is complicated mixture with valued chemicals. The hydrothermal liquefaction (HTL) converts directly the spirulina microalgae into liquid oil at reaction temperature 300°C with heating rate 10°C /min,100 bars pressure and 30 min. reaction time eight different organic solvents with different polarities were applied to extract the bio – oil from these chemicals. The order of bio–oil extraction yield of the eight solvents from high to low were as follow tetrahydrofuran (THF) ˃ dichloromethane (DCM) ˃ acetone (ACE) ˃ chloroform (CHL) ˃ methanol (MeOH)˃ ethyl-acetate (EAC) ˃ hexane (HEX) ˃toluene (TOL).The results obtained from single stage extraction process showed that maximum percentage oil yield was (26.55%). with rather high heating value (HHV ≈ 30 MJ/kg). The combination of THF, EAC and n-hexane was selected to extract and separate the bio – oil into three fraction heavy oil (48.9%) mid weight oil (37.8%) and light oil (62.2%). These three oils were characterized using gas chromatography mass spectrum (GC – mass). Keywords:- Bio–oil , extractives, hydrothermal , liquefaction, micro- algae.
Fractional kVA Rating PWM Converter Doubly Fed Variable Speed Electric Generator Systems:An Overview in 2020
Variable speed generator systems (VSGs) are at work in the now 600 GW installed wind power plants (parks). Also, they are used as vehicular and on ground stand-alone generators. VSGs imply full kVA rating PWM converters in permanent magnet (PM) or in electrically excited synchronous or in cage rotor inductance generators. But, to reduce cost in absence of PMs at a reasonable initial cost (weight) and efficiency, the fractional kVA PWM converter doubly fed induction generators (DFIG) cover now about 50% of all installed power in wind generators. The present paper reviews recent progress in DFIG and various forms of brushless DFGs (doubly fed generators) characterized in terms of topology, design, performance and advanced control for healthy and faulty load conditions in the hope of inspiring new, hopefully ground breakings, progress for wind and hydro energy conversion and in vehicular and on the ground stand-alone generator applications
Relationships between the Parity and Pelvimetry of Egyptian Buffalo Cows: Prediction of Dystocia and Estimation of Age
Background: The current study aimed to determine the most strongly correlated variable of pelvimetry with the parity in our native breed Egyptian buffaloes.
Methods: The study was conducted on 36 female buffaloes (nullipara, n=14, primipara n=6 and pluripara, n=16 with 2-4 births) aged between <15 months, n=15 and 65 months, n=21. The internal and external pelvic measurements were obtained using the rice pelvimeter and Freeman’s measuring tape.
Results: Strong positive linear relationships were found for the distance between ischiatic tuberosities and the distance between sacral tubercles with the correlation coefficients of 0.64 and 0.62, respectively. The conjugate diameter increased progressively with the age and number of births, with a correlation coefficient of 0.96. The pelvic area had a very strong positive linear relationship with a correlation coefficient of 0.89. The linear combination of the predictor variable (conjugate diameter), to predict the number of birth was developed successfully.
Conclusion: The strong relationship between the conjugate diameter and the number of births could be employed to predict the dystocia and estimate the age of female buffalo. Furthermore, these findings could be aid paleontologists in studying buffalo fossils
Does 24-48 or 48-96 Promote Better REM Sleep Within Firefighters?
A firefighter’s work schedule can be very demanding regardless if they work 24 hours followed by a 48-hour time off schedule or a 48-hour on followed by a 96-hour time off. Rapid Eye Movement (REM) sleep could be the deciding factor of how well a firefighter can perform following a certain work schedule. REM sleep is associated with the mental activity of dreaming; an individual averages 20-25% REM sleep of their total sleep time (Carskadon & Dement, 2005). REM is important for recovery because it can impact cognitive functions such as impulse control and decision making (Brunet, et al, 2020). This study examined the influence shift type had on REM sleep after a day of rest within 24-48, compared to a rest day within a 48-96 work schedule. PURPOSE: The study was designed to measure REM sleep on the 24-48 and 48-96 shift schedules and determine which shift type had a more optimal level of REM sleep. METHODS: 54 firefighters participated and were split into two cohorts depending on the department\u27s work schedule: 24-48 (n = 28) and 48-96 (n = 26). Data was collected through the use of WHOOP® (WHOOP, Inc.) wrist bands, which measures heart rate, HRV, strain, and sleep. A two-way ANOVA was utilized to determine the differences in shift type (24-48, 48-96) and day type, On Day 1 (OD1), On Day 2 (OD2), Rest Day 1 (RD1), Rest Day 2 (RD2), and Rest Day 3 (RD3). RESULTS: Participants exhibited 24.7 ± 9.2% of REM sleep. There was a significant difference between 24-48 OD1 REM (1.56 ± 0.66,) and 48-96 OD1 REM (1.31 ± 0.63) (p \u3c 0.001). Another significant difference existed between 48-96 RD1 REM (1.44 ± 0.71) and 48-96 RD2 REM (1.66 ± 0.78) (p = 0.004) as well as 48-96 RD3 REM (1.66 ± 0.68) (p = 0.007). No further significances were found when comparing shift days and rest days between the shift types. CONCLUSION: Therefore, shift type may have little effect on the amount of REM sleep a firefighter gets on a daily basis. Within the 48-96 shift type, significant differences in REM sleep amount do exist, indicating that recovery improves from the first and second rest day, with no further improvements after that
Prevalence, antibiotic resistance, and phylogenetic analysis of Listeria monocytogenes isolated from various sources in Egypt: fish, vegetables, and humans
Listeriosis is a severe infection caused by consuming food contaminated with Listeria monocytogenes, the primary cause of human listeriosis. This study aimed to identify L. monocytogenes phenotypically and genotypically using inlA and hlyA virulence genes, followed by DNA sequence analysis and antimicrobial sensitivity in food resources and human samples. 345 Samples were obtained randomly from different markets and supermarkets in Qena, Egypt, including 115 fish, 25 fish containers, 90 vegetables, 90 diarrheal samples, and 25 hand swabs from patients and fishermen, respectively. L. monocytogenes was confirmed in 11.30% (39/345) and 3.48% (12/345) of the examined samples using culture and conventional PCR methods, respectively. The frequencies of L. monocytogenes in fish, fish containers, vegetables, and humans were 8.70, 3.48; 20, 8; 18.89, 1.11 and 6.09, 4.35% by both methods, respectively, with a statistically significant difference. Although L. monocytogenes predominated in 5-17 and 31-43-year age groups, the age risk factor for patients was statistically insignificant from an epidemiological perspective. Higher incidences were found in females and urban areas 7.27 and 4.76% than in males and rural areas 0 and 3.70%, without a statistically significant difference. The inlA was identified in all isolates, but the hlyA was identified in 41.67%. The highest multiple antibiotic resistance (MAR) index 0.625 was found in a diarrheal swab; all collected isolates were completely resistant to ampicillin. Additionally, 25% of L. monocytogenes stains were multidrug-resistant. According to phylogenetic analysis, the local isolates obtained from samples of tilapia, catfish, fish containers, cauliflower, and humans shared plenty of similarities
Positional cloning of the barley tillering gene uniculme4
Manipulation of plant architectural traits such as the number of tillers can effectively increase grain yield in cereals. Within the frame of the TriticeaeGenome project (www.triticeaegenome.eu), the objective of our group was the fine mapping and positional cloning of uniculme4 (cul4), a gene required for tillering in barley. Based on initial medium resolution mapping of the locus, a segregating population including 4900 F3 plants was developed and genotyped with three tightly linked SNP markers (Tavakol et al., abstract P321, PAG XIX). The locus was further resolved through mapping of 8 synteny-derived markers allowing the identification of a candidate gene that co-segregates with the cul4 phenotype. The two genes that flank the candidate gene in Brachypodium and rice were positioned 0.11 cM and 0.12 cM from cul4, respectively: development of new markers is underway using sequence information from two BACs anchored to the physical map and spanning this region. The intron-exon structure of the candidate gene was determined from a cDNA isolated from wild-type plants. Resequencing of independent cul4 stocks identified three distinct mutations within the candidate gene, including a deletion of the 5\u2019 region. Comparison of expression levels and patterns in mutant and wild-type plants is underway
Bi-allelic GAD1 variants cause a neonatal onset syndromic developmental and epileptic encephalopathy.
Developmental and epileptic encephalopathies are a heterogeneous group of early-onset epilepsy syndromes dramatically impairing neurodevelopment. Modern genomic technologies have revealed a number of monogenic origins and opened the door to therapeutic hopes. Here we describe a new syndromic developmental and epileptic encephalopathy caused by bi-allelic loss-of-function variants in GAD1, as presented by 11 patients from six independent consanguineous families. Seizure onset occurred in the first 2 months of life in all patients. All 10 patients, from whom early disease history was available, presented with seizure onset in the first month of life, mainly consisting of epileptic spasms or myoclonic seizures. Early EEG showed suppression-burst or pattern of burst attenuation or hypsarrhythmia if only recorded in the post-neonatal period. Eight patients had joint contractures and/or pes equinovarus. Seven patients presented a cleft palate and two also had an omphalocele, reproducing the phenotype of the knockout Gad1-/- mouse model. Four patients died before 4 years of age. GAD1 encodes the glutamate decarboxylase enzyme GAD67, a critical actor of the γ-aminobutyric acid (GABA) metabolism as it catalyses the decarboxylation of glutamic acid to form GABA. Our findings evoke a novel syndrome related to GAD67 deficiency, characterized by the unique association of developmental and epileptic encephalopathies, cleft palate, joint contractures and/or omphalocele
Biology of barley shoot fly Delia flavibasis Stein (Diptera: Anthomyiidae) on resistant and susceptible barley cultivars
The biology of barley shoot fly Delia flavibasis was studied using resistant (Dinsho and Harbu) and susceptible (Holker) barley cultivars at Sinana Agricultural Research Center, Ethiopia. A higher number of eggs was laid on Holker (17 eggs/female) than on Dinsho (11 eggs/female) or Harbu (12 eggs/female). However, there were no differences between cultivars in preoviposition and total reproductive periods. The shortest time required to complete larval, pupal and total developmental stages from egg to adult emergence occurred when the insect was reared on the cultivar Holker. Pupal weight, adult emergence and adult longevity did not differ between cultivars. The female to male sex ratio was 1:1. This study enabled us to understand the duration of each of the life stages of D.flavibasis, which will undoubtedly aid researchers and growers to design a sustainable management strategy against barley shoot fly
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