Search

This article addresses the bifurcation characteristics and vibration reduction of a 2 -DOF dynamical system simulating the nonlinear oscillation of an asymmetric rotor model subjected to simultaneous multiparametric and external excitations. To suppress the system's vibrations, two 1 / 2 -DOF active dampers are attached to the system in linear and cubic nonlinear forms via a magnetic coupling actuator. The closed-loop system model is derived as two differential equations with multi-control terms, including cubic, quantic, and septic, coupled nonlinearly to two first-order systems. Applying perturbation theory, the system model is solved, and the autonomous system describing the closed-loop slow-flow dynamics is obtained. Through numerical algorithms, the motion bifurcation is analyzed using various tools such as 2D and 3D bifurcation diagrams, two-parameter stability charts, basins of attraction, orbit plots, and time response profiles. The analytical investigations confirm that the uncontrolled model behaves like a hardening Duffing oscillator with multistability characteristics, displaying simultaneous mono-stable, bi-stable, tri-stable, or quadri-stable periodic oscillations depending on both the asymmetric nonlinearities and angular velocity. Subsequently, the influence of different control parameters is analyzed to determine the threshold between mono and multi-stability conditions. Finally, optimal control parameters are designed to eliminate multistability characteristics and achieve minimum and safe vibration levels. [ABSTRACT FROM AUTHOR]

Islam is the most widespread religion in the world, and Islamic teachings emphasize the importance of seeking knowledge. As a result, Muslims are eager to provide educational opportunities for their children. Islamic schools in countries such as West Africa continue this tradition in modern times. This study aimed to explore the experiences and obstacles encountered by Islamic school leaders in The Gambia and Burkina Faso. It used a qualitative approach, specifically a case study methodology. Five principals from The Gambia participated in the first case study, while three principals from Burkina Faso participated in the second case study.The study revealed several significant findings. It showed that both countries' Islamic schools achieve better educational outcomes than public schools. Additionally, Islamic schools need more support related to funding and low teacher salaries. Both countries also need stronger administrative staff in Islamic schools. Based on the results, the paper presented several recommendations to improve the situation of Islamic schools in The Gambia and Burkina Faso. [ABSTRACT FROM AUTHOR]

A novel 3D chaotic oscillator that incorporates quadratic and absolute-function nonlinearities is introduced in this paper. The system dynamics are explored using the Lyapunov direct method, phase plane trajectories, time response, Lyapunov exponents, bifurcation diagrams, and basins of attraction. The uniqueness and existence of the system solution have been proven. The analytical investigations show that the system has two stable equilibrium points along with one unstable equilibrium point and a line of equilibria. The positive half of this line represents unstable equilibria, while the negative half is associated with stable equilibria. Additionally, it is found that the oscillator exhibits a chaotic basin of attraction centered along the line of equilibria and surrounded by a fixed-point attractor. An electronic circuit using Multisim software is designed to demonstrate the possibility of physical implementation for the considered mathematical model. Chaos control is addressed using adaptive and sliding mode control strategies. The performance of both control methods is compared, with the sliding mode control demonstrating superior results in both fast response and small transient overshoot. Furthermore, a novel sliding mode controller for master–slave synchronization is introduced, showing high performance compared to other sliding-mode and adaptive control methods applied in the literature. Finally, the proposed oscillator is employed as a Pseudo Random Number Generator (PRNG) for image encryption applications using a new encryption model. The experimental results confirm the high security and robustness of the proposed encryption algorithm against various attack methods. [ABSTRACT FROM AUTHOR]

Citizenship education is the effective educational tool in building a citizen who is able to participate in building his country. This can only come through the educational efforts that teachers make in the classroom. Such a step requires teachers to have knowledge of citizenship education, its principles, and the foundations for its development. Thus, the study aims to examine the degree of social studies teachers' knowledge of the dimensions of citizenship education at the basic education schools in the Sultanate of Oman. It also aims to examine its relationship with a set of variables. The researchers used the quantitative descriptive approach to achieve the objectives of the study. It further adopted a test tool, which consisted in its final form of five areas: citizenship knowledge, rights and duties, national identity, community partnership, and global and digital citizenship. The test was divided later into (38) multiple-choice questions. After verifying the validity and reliability of this tool, it was applied to a sample of (200) male and female teachers. The results of the study have shown that the degree of knowledge of social studies teachers in citizenship education was average, reaching the arithmetic level of (57.67%). Furthermore, there were no statistically significant differences in the level of knowledge of social studies teachers of citizenship education with respect to the variables of gender and educational qualification in the fields of citizenship education. Accordingly, the researchers have recommended that the citizenship education course should be included in teacher preparation programs at public and private universities in the Sultanate of Oman. Moreover, the concepts and principles of citizenship education should be included in the school curricula.

King Saud University is the leading higher institution of learning in Saudi Arabia, which focuses on providing its students with the best quality of education. With more than 4600 staff members, the University provides educational and research activities with modern state of the art technology to give its students a rewarding experience. It caters to various audiences ranging from students, to professors, researchers of diverse fields, and non-academics. KSU also opens its doors to all types of students, whether local or international. It provides skills acquisition training and workshops for its staff (including international trainings), in the fields of Arts and Sciences; thus, widening its scientific and literary expertise base (KSU, 2012). [ABSTRACT FROM AUTHOR]

Study design: Cross sectional Background:Diabetes mellitus type 1 (DM) is a serious chronic disease, with incidence rates ranging from 64/100,000 to 0.1/100,000 per year in various countries. A study of school-aged children in Istanbul, Turkey, discovered a frequency of 0.67/1 000. The prevalence of type 2 diabetes has also increased in school-aged children, accounting for 10-40% of adolescent diabetics. Diabetes is a disorder that necessitates ongoing monitoring of individuals. Early detection and appropriate management will lower the likelihood of illness consequences. Given that school-aged children spend the majority of their time at school, instructors can play an important role in the monitoring of diabetic students. Methods:In this cross - sectional study data was collected by the purposely constructed questionnaire. Questionnaire composed of the demographic items and items related to the DM and teacher's awareness regarding DM. Questionnaire was constructed after the series of discussions between the panel of experts this panel composed of from subject specialist, researcher, language expert. Cronbach alpha of the questionnaire was calculated. Results:39.7% considered DK is an emergency situation, 8.52% only believed that DK will effect kids only, taking multiple dose of insulin is the major risk factor, in emergency 56.82% will call the ambulance. Conclusion:There is a need for programs to educate teachers on diabetes and its management, as well as their roles in managing diabetic children in schools. Having a trustworthy source of DM knowledge for teachers will help them enhance their KAP level and increase their confidence in sharing and using their KAP. [ABSTRACT FROM AUTHOR]

This paper introduces a study on the horizontal and vertical deflections of the cross section of a thin-walled rotating beam. These deflections are governed by a system of two ordinary differential equations in order to describe their Cartesian directions. Based on multiple time-scales analysis, truncated asymptotic expansions are assumed to be approximate solutions to the given problem. Furthermore, an extracted autonomous system of differential equations governs the change rate of the amplitudes and phases of the beam deflections. The beam's rotation speed is adjusted to be in the neighborhood of both of the natural frequencies of the deflections such that the beam is subjected to 1 : 1 : 1 simultaneous resonance. A stability test is conducted according to the first method of Lyapunov in order to determine whether the equilibrium point is asymptotically stable or not. The beam's deflections turn unstable once its speed is in the neighborhood of its modal natural frequencies. There exists a multistable solution at some values of the beam's speed depending on the hysteresis manner of the model according to forward or backward sweeping of this speed. Furthermore, a range of centrifugal forces of the rotating hub can make the beam's deflections exhibit quasiperiodic responses which are confirmed by time response, orbital map, and amplitude spectrum. Eventually, some remarks are recommended for the external excitation frequency in order that the beam stays in the periodic behavior. [ABSTRACT FROM AUTHOR]

Background: Inflammatory bowel diseases (IBD), including Crohn's disease and ulcerative colitis, are chronic inflammatory conditions affecting the gastrointestinal tract. To achieve and sustain remission, effective treatment strategies are necessary. Ustekinumab, a biologic agent targeting interleukin-12 and interleukin-23, has emerged as a significant therapeutic option for moderate to severe IBD.Aim: To gain insights into the utilization of Ustekinumab for IBD, we conducted a comprehensive review of the ClinicalTrials.gov registry.Methods: A comprehensive search of the ClinicalTrials.gov was conducted to find all clinical trials involving the use of Ustekinumab in IBD patients. As of December 30th, 2022, 69 clinical trials were identified that included IBD and Ustekinumab. The study list was saved, and those clinical trials that fitted the definition of targeted therapy were included in the review.Results: The results showed that Ustekinumab was associated with significant improvements in the clinical response and remission rates, in both Crohn's disease and ulcerative colitis patients. Additionally, the safety profile of Ustekinumab was generally favourable, with low rates of adverse events reported. In terms of study design, most of the relevant studies found in the database were interventional studies. The investigation focused on completed studies and found that there were a limited number of clinical trials with interventional measures.Conclusion: Ustekinumab appears to be a promising treatment option for patients with IBD, with the potential to provide significant clinical benefits and a favourable safety profile. Further research is warranted to confirm these findings and explore optimal dosing and treatment regimens. [ABSTRACT FROM AUTHOR]

Within this work, an advanced control algorithm was proposed to eliminate the non-linear vibrations of the rotor electro-magnetic suspension system. The suggested control algorithm is known as the Adaptive Linear Integral Positive Position Feedback controller (ALIPPF-controller). The ALIPPF-controller is a combination of first-order and second-order filters that are coupled linearly to the targeted non-linear system in order to absorb the excessive vibratory energy. According to the introduced control strategy, the dynamical model of the controlled rotor system was established as six non-linear differential equations that are coupled linearly. The obtained dynamical model was investigated analytically applying the asymptotic analysis, where the slow-flow equations were extracted. Based on the derived slow-flow equations, the bifurcation behaviors of the controlled system were explored by plotting the different bifurcation diagrams. In addition, the performance of the ALIPPF-controller in eliminating the rotor lateral vibrations was compared with the conventional Positive Position Feedback (PPF) controller. The acquired results illustrated that the ALIPPF-controller is the best control technique that can eliminate the considered system's lateral vibrations regardless of the angular speed and eccentricity of the rotating shaft. Finally, to demonstrate the accuracy of the obtained analytical results, numerical validation was performed for all obtained bifurcation diagrams that were in excellent agreement with the analytical solutions. [ABSTRACT FROM AUTHOR]

Design: A descriptive cross-sectional study. Aim: The current study aims to assess the knowledge, attitude and practice of urinary tract infection among female in Aseer region. Methods: A descriptive cross-sectional study was conducted targeting all women in Aseer region aging 18 years or more. All accessible women in general population were invited to fill the uploaded questionnaire consecutively during the period from April-2021 to October 2021 The questionnaire included women personal data, women knowledge of UTI, attitude and perception and practice regarding UTI. Questionnaire was uploaded online using social media platforms by the researchers and their relatives and friends. Results: A total of 855 females fulfilling the inclusion criteria completed the study questionnaire. Female ages ranged from 18 to more than 40 years with mean age of 31.6 ± 9.7 years old. Exact of 615 71.9% females were married and 205 24% were single. Exact of 80.5% of the study participants know what is UTI. A total of 14.6% defined UTI as inflammation of the balder, 9.9% defined it as inflammation of the urethra, and 74.3% defined as inflammation of bladder, kidney and urethra. As for causes of UTI, only 108 12.6% correctly reported for personal hygiene while 73.3% told about bacteria. A total of 569 66.5% participants reported experiencing UTI which was for only once per year among 58.3% of them, and for 2 times per year among 18.6%. Ad for symptoms experienced, 76.1% had pain in urination, 71.2% complained of abdominal pain, 56.6% had urge, 50.4% experienced frequent urination, while 41.5% had fever. Conclusion: The study revealed that nearly two out of each three women were knowledgeable regarding UTIs and about one out of each two showed good perception and attitude. Women practice regarding UTIs was also satisfactory especially for seeking for medical consultation and fluid intake. [ABSTRACT FROM AUTHOR]

Design: A descriptive cross-sectional study. Aim: The current study aims to assess the knowledge, attitude and practice of urinary tract infection among female in Aseer region. Methods: A descriptive cross-sectional study was conducted targeting all women in Aseer region aging 18 years or more. All accessible women in general population were invited to fill the uploaded questionnaire consecutively during the period from April-2021 to October 2021 The questionnaire included women personal data, women knowledge of UTI, attitude and perception and practice regarding UTI. Questionnaire was uploaded online using social media platforms by the researchers and their relatives and friends. Results: A total of 855 females fulfilling the inclusion criteria completed the study questionnaire. Female ages ranged from 18 to more than 40 years with mean age of 31.6 ± 9.7 years old. Exact of 615 71.9% females were married and 205 24% were single. Exact of 80.5% of the study participants know what is UTI. A total of 14.6% defined UTI as inflammation of the balder, 9.9% defined it as inflammation of the urethra, and 74.3% defined as inflammation of bladder, kidney and urethra. As for causes of UTI, only 108 12.6% correctly reported for personal hygiene while 73.3% told about bacteria. A total of 569 66.5% participants reported experiencing UTI which was for only once per year among 58.3% of them, and for 2 times per year among 18.6%. Ad for symptoms experienced, 76.1% had pain in urination, 71.2% complained of abdominal pain, 56.6% had urge, 50.4% experienced frequent urination, while 41.5% had fever. Conclusion: The study revealed that nearly two out of each three women were knowledgeable regarding UTIs and about one out of each two showed good perception and attitude. Women practice regarding UTIs was also satisfactory especially for seeking for medical consultation and fluid intake. [ABSTRACT FROM AUTHOR]