1,708 research outputs found
Evaluating a ZigBee Network with SMC for Hard and Concurrent Parameter Variations
One of the main issues concerning a wireless networked control system is the variable delay associated with the communicating network used to join its dispersed components. This paper presents a variable structured Sliding Mode Controller (SMC) designed for a ZigBee wireless networked control system (WNCS) in addition to the design of a standard PID controller. WNCS can improve the reliability and the effectiveness of the control system by eliminating time and costs of installation and maintenance. Presence of time delays between sensors, actuators and controllers of the controlled system can degrade the performance and destabilize the whole system. To reduce the effect of the network delay, simulation tools for WNCS are developed to help designers in studying the influence of network on performance of the control system. The TrueTime toolbox is used to analyze the effects of network delays and to evaluate the effects of ZigBee parameters on control systems such as packet loss, ACK. Timeout limit, and traffic load. It is clear from the results that SMC is superior to PID control. Keywords: NCS, SMC, PID, ZigBee, TrueTim
Derivation of Bearing Capacity Equation for a Two Layered System of Weak Clay Layer Overlaid by Dense Sand Layer
Calculation of the ultimate bearing capacity of shallow footing on a two layered
system of soil depends on the pattern of the failure surface that develops below
the footing. For a weak clay layer overlaid by a top dense sand layer, previous
studies assumed that the failure surface is a punching shear failure through the
upper sand layer and Prandtl's failure mode in the bottom weak clay layer. By
adapting this assumption in this study, the ultimate bearing capacity equation
was derived as a function of the properties of soils, the footing width, and the
topsoil thickness. The paper presents a detailed parametric study of the design
parameters including the effect of angle of friction, the ratio of the thickness
of sand layer to the footing width, the ratio of the depth of embedment to the
footing width, and the ratio of the clay soil cohesion to the product of the clay
unit weight by the footing width. Design charts were developed in dimensionless
form for very wide ranges of design parameters. The available method based on
the limit equalibrium analysis was developed in dimensionlised form and for a
limited range of design parametrs. The new charts give another option for
those who believe that the design charts developed based on the upper limit
analysis overestimate the bearing capacity due to the very nature of the upper
bound solution. The new design charts are limited to shallow footings
Antibacterial Activities of Yansoon (Pimpinella anisum L.), Ginger (Zingiber officinale L.) and Cinnamon (Cinnamomum zeylanicum L.) Extracts
There is an increasing demand for the biologically active substances from plant origin which is of current interest and focus for new research approach. The synthetic pharmaceuticals compounds showed various side effects on functions of different parts of the human body, both internally and externally. Therefore, the present study was investigating the antimicrobial activity of three important herbs, Ginger (Zingiber officinale L.), Yansoon (Pimpinella anisum L.) and Cinnamon (Cinnamomum zeylanicum L.). The cup- plate agar (inhibition zone) method was used for studying the effects of the extracts against Streptococcus sp, Staphylococcus aureus and Enterococcus faecalis. The results showed that, the ethanol extracts of cinnamon and the combination of ginger and cinnamon were highly effective on Streptococcus sp (24mm and 21mm, respectively), compared to the water extracts (15mm and16mm, respectively). However, the water and the ethanol extracts of ginger and yansoon were less effective (11mm, 9mm, 8.5mm and 8mm, respectively). The ethanol extracts of cinnamon and the combination of ginger and cinnamon were highly effective on Staphylococcus aureus giving (24mm and 21.5 mm, respectively) followed by water extract (20mm and 21 mm, respectively). While, the ethanol and water extracts of ginger and yansoon were less effective (11mm, 10.5mm, 9mm and 9.5mm, respectively). The ethanol and water extracts of cinnamon were highly effective on E. faecalis giving (21mm and 20.5 mm, respectively). The ethanol extracts of the combination of ginger and cinnamon were effective (20 mm) followed by water extract (18mm). The water and ethanol extracts of ginger and yansoon were less effective giving (15 mm, 12 mm, 8 mm and 9 mm, respectively). From the results it could be concluded that, the extracts of (Cinnamon, Yansoon and Ginger) can be used as antimicrobial agents. It could be suggested that the active antimicrobial components need to be verified in any further study and more microorganism are to be tested .
 
Late Diagnosis of 5-α-Reductase Type 2 Deficiency in an Adolescent Girl with Primary Amenorrhoea : Case report
Deficiency of the 5-α-reductase enzyme has been found to affect male sexual development. We report an 18-year-old patient who was referred to an endocrinology clinic in Jizan, Saudi Arabia, in April 2014 with primary amenorrhoea, virilisation and a lack of secondary sex characteristics. As female external genitalia were present at birth, she had been raised as a female. Magnetic resonance imaging revealed no uterine or ovarian tissue in the pelvis and the presence of a scrotal sac. She was diagnosed with 5-α-reductase type 2 deficiency, a 46,XY disorder of sexual development. Typically, affected males have pseudovaginal perineoscrotal hypospadias and ambiguous genitalia at birth. Individuals who have been raised as female manifest characteristics of virilisation at puberty, including deepening of the vocal tone, phallus enlargement, scrotal hyperpigmentation and increased muscle mass
Preventing type 2 diabetes mellitus in Qatar by reducing obesity, smoking, and physical inactivity: mathematical modeling analyses.
BACKGROUND: The aim of this study was to estimate the impact of reducing the prevalence of obesity, smoking, and physical inactivity, and introducing physical activity as an explicit intervention, on the burden of type 2 diabetes mellitus (T2DM), using Qatar as an example. METHODS: A population-level mathematical model was adapted and expanded. The model was stratified by sex, age group, risk factor status, T2DM status, and intervention status, and parameterized by nationally representative data. Modeled interventions were introduced in 2016, reached targeted level by 2031, and then maintained up to 2050. Diverse intervention scenarios were assessed and compared with a counter-factual no intervention baseline scenario. RESULTS: T2DM prevalence increased from 16.7% in 2016 to 24.0% in 2050 in the baseline scenario. By 2050, through halting the rise or reducing obesity prevalence by 10-50%, T2DM prevalence was reduced by 7.8-33.7%, incidence by 8.4-38.9%, and related deaths by 2.1-13.2%. For smoking, through halting the rise or reducing smoking prevalence by 10-50%, T2DM prevalence was reduced by 0.5-2.8%, incidence by 0.5-3.2%, and related deaths by 0.1-0.7%. For physical inactivity, through halting the rise or reducing physical inactivity prevalence by 10-50%, T2DM prevalence was reduced by 0.5-6.9%, incidence by 0.5-7.9%, and related deaths by 0.2-2.8%. Introduction of physical activity with varying intensity at 25% coverage reduced T2DM prevalence by 3.3-9.2%, incidence by 4.2-11.5%, and related deaths by 1.9-5.2%. CONCLUSIONS: Major reductions in T2DM incidence could be accomplished by reducing obesity, while modest reductions could be accomplished by reducing smoking and physical inactivity, or by introducing physical activity as an intervention
PROPERTIES OF DRINKING YOGHURT USING DIFFERENT TYPES OF STABILIZERS
Different types of drinking yoghurts were made with different types and concentrations of stabilizers. 6 treatments were made (T1, T2, T3, T4, T5 and T6) using 0.2% and 0.4% of different types stabilizers ( pectin, guar gum, and mixture (1:1) of both pectin and guar gum) for production of other yoghurt drink treatments beside the control without any stabilizers. All treatments were stored up to 14 days at 5±1°C. Drinking yoghurt samples were evaluated for chemical, reholigical, microbiological and sensory attributes. No significant differences were observed in chemical and microbiological properties among control and treated samples. All drinking yoghurt contained levels of (106–107 cfu/g) lactic acid bacteria at the end of the refrigerated storage. Addition of stablizers showed significant differences in viscocitey and serum separation of final product. The effect was more obvious with using 0.2% stabilizer mixture (0.1% guar gum + 0.1% High Methoxy Pectin) than other all treatments. The drinking yoghurt containing 0.2% mix stabilizers (0.1% guar gum + 0.1% High Methoxy Pectin) ranked higher sensory scores than other treatments. The best drinking yoghurt that containing 50% yoghurt, 8% sugar and 42% water should be fortified with 0.2% mix stabilizers (0.1% guar gum + 0.1% High Methoxy Pectin
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