Finite-time extended state observer and fractional-order sliding mode controller for impulsive hybrid port-Hamiltonian systems with input delay and actuators saturation: Application to ball-juggler robots

This paper addresses the robust control problem of mechanical systems with hybrid dynamics in port-Hamiltonian form. It is assumed that only the position states are measurable, and time-delay and saturation constraint affect the control signal. An extended state observer is designed after a coordinate transformation. The effect of the time delay in the control signal is neutralized by applying Pade ́ approximant and augmenting the system states. An assistant system with faster convergence is developed to handle actuators saturation. Fractional-order sliding mode controller acts as a centralized controller and compensates for the undesired effects of unknown external disturbance and parameter uncertainties using the observer estimation results. Stability analysis shows that the closed-loop system states, such as the observer tracking error, and the position/velocity tracking errors, are finite-time stable. Simulation studies on a two ball-playing juggler robot with three degrees of freedom validate the theoretical results’ effectiveness

Finite-time disturbance reconstruction and robust fractional-order controller design for hybrid port-Hamiltonian dynamics of biped robots

In this paper, disturbance reconstruction and robust trajectory tracking control of biped robots with hybrid dynamics in the port-Hamiltonian form is investigated. A new type of Hamiltonian function is introduced, which ensures the finite-time stability of the closed-loop system. The proposed control system consists of two loops: an inner and an outer loop. A fractional proportional-integral-derivative filter is used to achieve finite-time convergence for position tracking errors at the outer loop. A fractional-order sliding mode controller acts as a centralized controller at the inner-loop, ensuring the finite-time stability of the velocity tracking error. In this loop, the undesired effects of unknown external disturbance and parameter uncertainties are compensated using estimators. Two disturbance estimators are envisioned. The former is designed using fractional calculus. The latter is an adaptive estimator, and it is constructed using the general dynamic of biped robots. Stability analysis shows that the closed-loop system is finite-time stable in both contact-less and impact phases. Simulation studies on two types of biped robots (i.e., two-link walker and RABBIT biped robot) demonstrate the proposed controller's tracking performance and disturbance rejection capability

The Reasons of Students’ Unwillingness to Receive Vocational Education

The present study aimed to explore the reasons of students’ unwillingness to receive vocational education in Jordan from the perspective of faculty members. It aimed to explore whether there are statistically significant differences between respondents’ attitudes which can be attributed to gender, faculty, academic rank and the country that the PhD certificate was obtained. A descriptive analytical approach was adopted. Data was collected through using a questionnaire. Questionnaire forms were distributed to (200) faculty members who work at the University of Jordan.  They were selected from the faculty of educational sciences and King Abdullah II School of Information Technology. 154 questionnaire forms were retrieved. The response rate is 77%. It was found that there are three types of reasons of students’ unwillingness to receive vocational education in Jordan. These types are: psychological, social and economic reasons. In terms of the psychological reasons, the ones who practice a vocation do not enjoy a high job stability level. In addition, practicing a vocation requires exerting much physical effort. In terms of the social reasons, the ones who practice a vocation do not enjoy a high social standing. In addition, the opinions made by the ones who practice a vocation about daily life issues aren’t taken seriously. In terms of the economic reasons, the ones who practice a vocation do not have a high& stable income. The researchers recommend motivating students to enroll in vocational educational schools through providing them with moral and financial incentives. Keywords: Vocational education, students, faculty members, Jordan DOI: 10.7176/JEP/11-4-03 Publication date: February 29th 202

Comparison of urinary and plasma ketone using urinary nitroprusside strip in patients with diabetic ketoacidosis

Background: Diabetic ketoacidosis is one of the most important and serious acute complications of diabetes and one of the medical emergencies that has been the most common cause of death in patients with diabetes. Prompt diagnosis and therapeutic intervention play an important role in reducing complications and mortality. The aim of this study was to compare urinary and plasma ketones using urinary nitroprusside strip in patients with diabetic ketoacidosis. Methods: In this cross-sectional study, 38 diabetic ketoacidosis patients were included in this study during the years 2017 and 2018 in the emergency department of Imam Khomeini hospital in Ardabil city. To test for plasma ketones, 2 cc of venous blood samples were taken and transferred to the laboratory for plasma isolation. The resulting plasma was examined with a urine dipstick and the discoloration was recorded. This was repeated at 0, 6 and 12 o'clock for serum ketones. All patients received their treatment according to the treatment protocol of diabetic ketoacidosis and urine ketone, PH and bicarbonate and BE patients were measured routinely. Results: Serum ketones were positive in all patients and 34 patients had positive urinary ketones. In this study, serum ketone levels were significantly correlated with blood acidity at baseline and with bicarbonate and basal arterial gas deficit at all three stages. However, urinary ketones had a significant correlation with blood acidity at baseline and at 12 hours, with bicarbonate at baseline and with arterial gas deficiency at 12 hours. Conclusions: The results showed that examination of plasma ketones with dipstick can be a useful, rapid and accurate clinical trial for the diagnosis of diabetic ketoacidosis in patients with diabetes

Fuzzy spatial association rule mining to analyze the effect of environmental variables on the risk of allergic asthma prevalence

The prevalence of allergic diseases has greatly increased in recent decades, likely due to contamination of the environment with allergy irritants. One common treatment is identifying that allergy irritant, and then avoiding exposure to it. This article studies the relation between the prevalence of allergic asthma and certain allergy irritants that are related to environmental variables. To that end, we use spatial association rule mining to determine the association between the spatial distribution of allergic asthma prevalence and air pollutants such as CO, SO2, NO2, PM10, PM2.5, and O3 (from data compiled by air pollution monitoring stations), as well as other factors, such as the distance of residence from parks and roads. In order to clear up the uncertainties inherent in the attributes linked to the spatial data, the dimensions in question have been defined as fuzzy sets. Results for the case study (i.e. Tehran metropolitan area) indicate that distance to parks and roads, as well as CO, NO2, PM10, and PM2.5 levels are related to allergic asthma prevalence, while SO2 and O3 are not. Finally, we use the extracted association rules in fuzzy inference system to produce the spatial risk map of allergic asthma prevalence, which shows how much is the risk of allergic asthma prevalence at each point of the city

A Review of Enzymatic Transesterification of Microalgal Oil-Based Biodiesel Using Supercritical Technology

Biodiesel is considered a promising replacement to petroleum-derived diesel. Using oils extracted from agricultural crops competes with their use as food and cannot realistically satisfy the global demand of diesel-fuel requirements. On the other hand, microalgae, which have a much higher oil yield per hectare, compared to oil crops, appear to be a source that has the potential to completely replace fossil diesel. Microalgae oil extraction is a major step in the overall biodiesel production process. Recently, supercritical carbon dioxide (SC-CO2) has been proposed to replace conventional solvent extraction techniques because it is nontoxic, nonhazardous, chemically stable, and inexpensive. It uses environmentally acceptable solvent, which can easily be separated from the products. In addition, the use of SC-CO2 as a reaction media has also been proposed to eliminate the inhibition limitations that encounter biodiesel production reaction using immobilized enzyme as a catalyst. Furthermore, using SC-CO2 allows easy separation of the product. In this paper, conventional biodiesel production with first generation feedstock, using chemical catalysts and solvent-extraction, is compared to new technologies with an emphasis on using microalgae, immobilized lipase, and SC-CO2 as an extraction solvent and reaction media

Study of atmospheric pollution and health risk assessment: A case study for the sharjah and ajman emirates (uae)

Dust is a significant pollution source in the United Arab Emirates (UAE) that impacts population health. Therefore, the present study aims to determine the concentration of heavy metals (Cd, Pb, Cr, Cu, Ni, and Zn) in the air in the Sharjah and Ajman emirates’ urban areas and assesses the health risk. Three indicators were used for this purpose: the average daily dose (ADD), the hazard quotient (HQ), and the health index (HI). Data were collected during the period April–August 2020. Moreover, the observation sites were clustered based on the pollutants’ concentration, given that the greater the heavy metal concentration is, the greater is the risk for the population health. The most abundant heavy metal found in the atmosphere was Zn, with a mean concentration of 160.30 mg/kg, the concentrations of other metals being in the following order: Ni \u3e Cr \u3e Cu \u3e Pb \u3e Cd. The mean concentrations of Cd, Pb, and Cr were within the range of background values, while those of Cu, Ni, and Zn were higher than the background values, indicating anthropogenic pollution. For adults, the mean ADD values of heavy metals decreased from Zn to Cd (Zn \u3e Ni \u3e Cr \u3e Cu \u3e Pb \u3e Cd). The HQ (HI) suggested an acceptable (negligible) level of non-carcinogenic harmful health risk to residents’ health. The sites were grouped in three clusters, one of them containing a single location, where the highest concentrations of heavy metals were found

Long-term testosterone therapy improves liver parameters and steatosis in hypogonadal men: a prospective controlled registry study

Non-alcoholic fatty liver disease (NAFLD) is associated with cardiovascular disease (CVD) and both are prevalent in men with testosterone deficiency. Long-term effects of testosterone therapy (TTh) on NAFLD are not well studied. This observational, prospective, cumulative registry study assesses long-term effects of testosterone undecanoate (TU) on hepatic physiology and function in 505 hypogonadal men (T levels ≤350 ng/dL). Three hundred and twenty one men received TU 1000 mg/12 weeks for up to 12 years following an initial 6-week interval (T-group), while 184 who opted against TTh served as controls (C-group). T-group patients exhibited decreased fatty liver index (FLI, calculated according to Mayo Clinic guidelines) (83.6 ± 12.08 to 66.91 ± 19.38), γ-GT (39.31 ± 11.62 to 28.95 ± 7.57 U/L), bilirubin (1.64 ± 4.13 to 1.21 ± 1.89 mg/dL) and triglycerides (252.35 ± 90.99 to 213 ± 65.91 mg/dL) over 12 years. Waist circumference and body mass index were also reduced in the T-group (107.17 ± 9.64 to 100.34 ± 9.03 cm and 31.51 ± 4.32 to 29.03 ± 3.77 kg/m2). There were 25 deaths (7.8%) in the T-group of which 11 (44%) were cardiovascular related. In contrast, 28 patients (15.2%) died in C-group, and all deaths (100%) were attributed to CVD. These data suggest that long-term TTh improves hepatic steatosis and liver function in hypogonadal men. Improvements in liver function may have contributed to reduced CVD-related mortality