Analysis and design of single-fed circularly polarized circular microstrip antennas

A novel design of a circular microstrip antenna with an additional small circular patch excited by a single feed for achieving a dual band frequency operation with circular polarization (CP) is presented. The implemented dual band circularly polarized antenna has a compact configuration that serves the technology demands requirements in mobile unit systems for smaller volume. Simulation and experimental results show that the 10 dB return-loss impedance bandwidth is better than that of a conventional single circular microstrip patch antenna. In addition, a dual frequency band operation at 2.45 GHZ and 5.2GHZ is obtained. A second antenna design suitable for an integrated circuits demand is also presented. Results demonstrate that both sense left hand and right hand circular polarization (RHCP, LHCP) can be achieved using this technique. A comparison between theoretical and experimental results is provided and shows good match. The resonance frequencies and quality of the axial ratio can be controlled by changing the radii of the two circles, and the orientation of the additional circular patch relative to the main patch. For other desired frequencies, the design of the antenna can be carried out by calculating the radii of the main and additional patch using empirical equations acquired for this design. The empirical formulas are developed based on a comprehensive parametric study where different designs and material parameters are varied to achieve an optimum antenna performance. A 64-element uniform linear array of circular microstrip patch antennas is designed and simulated for achieving circular polarization (CP) with more than (20 dB) directivity. Since the axial ratio bandwidth of the implemented antenna is narrow, a sequential rotation of radiating patches with suitable excitation phase shifting has been applied to improve the polarization purity over a wide range of frequencies with higher gain compared to a single patc

The hydrodynamic Effect of the Hyaluronic Acid on the Performance Improvement of the Human Synovial Joint

The aim of this article is to present an the theoretical analysis of the problem is presented through a mathematical model  depended on the idea of a Hyaluronic acid (HA) in cartilage  and  synovial fluid surrounding the joints (hip, knee and ankle)  where are a major component of synovial fluid modified  Reynolds equation  governing the fluid film pressure was derived and solved analytically,  and closed form expressions for the squeeze film pressure and load carry capacity were  presented. The influence of film thickness and sliding motion on the squeeze film Characteristics were discussed .It has been found that the effect of  decreased film thickness tend to increased the load carry capacity , friction force and decreased  flow rate, The effect of decreased sliding motion tend to increasing frication force and decreased flow rate and  when additives Hyaluronic acid (HA) to bearing material (articular cartilage ) .The results indicate to  increasing pressure distribution (P) and improve both load carry capacity (W), friction force (F) Compared to the disease synovial hip joint. Keywords: Hyaluronic acid , Hip joint, load carry capacity, friction force.

The Effects of Surface Roughness on the Squeeze Film Characteristics with Couple stress fluids in Hip joint

On the basis of the Stokes micro continuum theory , This paper aims to study the effects of surface roughness and couple stress on the squeeze film Characteristics in hip joint. The cartilage is modeled as biphasic poro-elastic  matrix and synovial fluid is modeled as couple stress fluid  . Compared to the conventional Newtonian lubricant case, the couple stress and surface roughness effects characterized by the couple stress and surface roughness parameter signify an improvement in the squeeze film Characteristics. Increasing values of the  surface roughness  parameter increases the load-carrying capacity and the squeeze in the squeeze film can be decreased and provides a longer time to prevent sphere –plane surface contact .The approaching time of the sphere in reducing the film thickness h*=1 to h*= 0for the couple stress fluid lubricant which is longer than surface roughness. Keywords: Surface roughness, Couple stress fluid, Articular cartilage, Synovial fluid, Micro continuum theory, Hip joint

The New and the Old: Responses to Change in the Kingdom of Saudi Arabia

This qualitative study was primarily concerned with Saudi women’s reactions to social change in the political sphere. It focused on their responses to decrees allowing women to vote in municipal elections for the first time, become candidates in such elections, and be nominated in the Shura Council by the King. Structured interviews of urban dwellers illustrated that changes, seen as opportunities, had been noted, but their impact had yet to be processed thoroughly. Attitudes towards political participation were positive and largely optimistic, but rarely seen as applying to the self. Competence, rather than gender, was seen as relevant to voters’ views of political candidates as well as of elected or appointed officials. Compared with older interviewees, young ones viewed the impact of women’s political participation, along with other social changes, as gradual, manageable, and merely one of the many articulations of the 2030 Vision, a strategic framework developed by KSA intended to reduce the country’s dependence on oil and diversify its economy. Both young and older interviewees, though, were reluctant to forecast its specific future impact. Actual political participation, in the form of either voting or running for office, was dismal. These results indicate that not only time is needed for top-down interventions to enter the social fabric of a nation and the minds of its people, but also the necessary conditions must exist that enable the genuine flourishing of human agency

Awareness and Regulatory Measures in Caffeine Addiction: Medical Statistical Review

This study aimed at analyzing the degree of awareness and regulatory measures in the caffeine addiction within a medical statistical survey in Jordan, by attempting to answer the study two questions: What are the level of awareness and regulatory measures in caffeine addiction for positive psychological effects (alertness, attention and concentration)?, and: What are the level of awareness and regulatory measures in caffeine addiction for negative psychological effects (anxiety, depression and irritable)? The results of the study showed that there will be a statistically significant differences at the level of significance (α=0.05) of the awareness of caffeine addiction for both positive psychological effects (alertness, attention and concentration) and negative psychological effects (anxiety, depression and irritable) in Jordan. The researchers recommended to educate university students about the importance of controlling their caffeine intakes, and encourage university students to exploit the medical information provided by the medical studies about the risks of high doses of caffeine intakes

On the Bohr inequality

The Bohr inequality, first introduced by Harald Bohr in 1914, deals with finding the largest radius $r$, $0<r<1$, such that $\sum_{n=0}^\infty |a_n|r^n \leq 1$ holds whenever $|\sum_{n=0}^\infty a_nz^n|\leq 1$ in the unit disk $\mathbb{D}$ of the complex plane. The exact value of this largest radius, known as the \emph{Bohr radius}, has been established to be $1/3.$ This paper surveys recent advances and generalizations on the Bohr inequality. It discusses the Bohr radius for certain power series in $\mathbb{D},$ as well as for analytic functions from $\mathbb{D}$ into particular domains. These domains include the punctured unit disk, the exterior of the closed unit disk, and concave wedge-domains. The analogous Bohr radius is also studied for harmonic and starlike logharmonic mappings in $\mathbb{D}.$ The Bohr phenomenon which is described in terms of the Euclidean distance is further investigated using the spherical chordal metric and the hyperbolic metric. The exposition concludes with a discussion on the $n$-dimensional Bohr radius

ЭЛЕКТРОМАГНИТНЫЕ ХАРАКТЕРИСТИКИ УГЛЕРОДСОДЕРЖАЩЕГО НЕТКАНОГО МАТЕРИАЛА С ГЕОМЕТРИЧЕСКИМИ НЕОДНОРОДНОСТЯМИ

The results of the study of electromagnetic characteristics of the carbon-containing non-woven fabric with geometric irregularities in the frequency range 0.7…17 GHz are presented.Представлены результаты исследования электромагнитных характеристик углеродсодержащих нетканых материалов с геометрическими неоднородностями в диапазоне частот 0,7…17 ГГц

Patient-provider interaction from the perspectives of type 2 diabetes patients in Muscat, Oman: a qualitative study

<p>Abstract</p> <p>Background</p> <p>Patients' expectations and perceptions of the medical encounter and interactions are important tools in diabetes management. Some problems regarding the interaction during encounters may be related to a lack of communication skills on the part of either the physician or the patient.</p> <p>This study aimed at exploring the perceptions of type 2 diabetes patients regarding the medical encounters and quality of interactions with their primary health-care providers.</p> <p>Methods</p> <p>Four focus group discussions (two women and two men groups) were conducted among 27 purposively selected patients (13 men and 14 women) from six primary health-care centres in Muscat, Oman. Qualitative content analysis was applied.</p> <p>Results</p> <p>The patients identified some weaknesses regarding the patient-provider communication like: unfriendly welcoming; interrupted consultation privacy; poor attention and eye contact; lack of encouraging the patients to ask questions on the providers' side; and inability to participate in medical dialogue or express concerns on the patients' side. Other barriers and difficulties related to issues of patient-centeredness, organization of diabetes clinics, health education and professional competency regarding diabetes care were also identified.</p> <p>Conclusion</p> <p>The diabetes patients' experiences with the primary health-care providers showed dissatisfaction with the services. We suggest appropriate training for health-care providers with regard to diabetes care and developing of communication skills with emphasis on a patient-centred approach. An efficient use of available resources in diabetes clinics and distributing responsibilities between team members in close collaboration with patients and their families seems necessary. Further exploration of the providers' work situation and barriers to good interaction is needed. Our findings can help the policy makers in Oman, and countries with similar health systems, to improve the quality and organizational efficiency of diabetes care services.</p