Magnetic Beamforming for Wireless Power Transfer

Magnetic resonant coupling (MRC) is an efficient method for realizing the near-field wireless power transfer (WPT). The use of multiple transmitters (TXs) each with one coil can be applied to enhance the WPT performance by focusing the magnetic fields from all TX coils in a beam toward the receiver (RX) coil, termed as "magnetic beamforming". In this paper, we study the optimal magnetic beamforming for an MRC-WPT system with multiple TXs and a single RX. We formulate an optimization problem to jointly design the currents flowing through different TXs so as to minimize the total power drawn from their voltage sources, subject to the minimum power required by the RX load as well as the TXs' constraints on the peak voltage and current. For the special case of identical TX resistances and neglecting all TXs' constraints on the peak voltage and current, we show that the optimal current magnitude of each TX is proportional to the mutual inductance between its TX coil and the RX coil. In general, the problem is a non-convex quadratically constrained quadratic programming (QCQP) problem, which is reformulated as a semidefinite programming (SDP) problem. We show that its semidefinite relaxation (SDR) is tight. Numerical results show that magnetic beamforming significantly enhances the deliverable power as well as the WPT efficiency over the uncoordinated benchmark scheme of equal current allocation.Comment: 13 Pages, 3 figures, submitted to IEEE ICASSP 201

Investigating the effect of corporate governance on risk of private banks and insurance firms

This paper presents an empirical investigation to study the effects of corporate governance on risk taking of private insurance firms and banks in Iran. The proposed study of this paper considers the financial information of 13 banks and 19 private insurance firms over the period 2006-2011 in Iran. The study investigates the effects of five variables including size, CEO duality task, composition of the board of directors, ownership concentration and having an internal auditing system on risk taking of private banks and insurance firms in Iran. Using some panel data and regression analysis, the study confirms the positive effect of the ownership concentration as well as negative impact of non-bound board members on risk taking

The Study of Impact of Intellectual Capital (Human, Customer, and Structural) on Performance of Ferdowsi Financial and Credit Institute

Knowledge economy is a branch of economy which considers knowledge and invisible assets of organizations as a main advantage of competition as organizations' success depends on ability of management and use of these invisible assets. For a simple classification, Invisible assets were divided into two groups supported by law . For intellectual capital, different classifications have been provided, which is divided into three components of human, communication and organizational. In this research, the study was done on mutual relations between components of intellectual capital and their impacts on financial performance of Ferdowsi financial and credit institute. The research method is descriptive correlation and is based on structural equations modeling . For this purpose, a questionnaire with 51 questions for components of intellectual capital was designed and rate of financial performance of Mellat Bank branches was obtained through covering analysis of data. In this research, firstly by using factor analysis in first stage, the factors of triple field of intellectual capital were extracted and then, by using confirmatory factor analysis, the validity of measuring models was confirmed. Results of data analysis, by using structural equation modeling showed that there is a strong relation between components of intellectual capitals but these capitals have no impact on organization performance in branches of Ferdowsi financial and credit institute. Finally, some suggestions were provided for use of balance evaluation card in improvement of financial performance of branches of Ferdowsi financial and credit institute

Nanoparticles and plant Biotechnology

Among the advances in technology, nanotechnology has an important role. With increasing rate of population, traditional agriculture will not be accountable the population food needs. The use of plants to produce nanoparticles is a biological system, cost-effective and environmentally friendly. The aim from nanotechnology in agriculture and biotechnology is development new methods for rapid diagnosis of plant diseases and needs with the use of biosensors, improving agricultural products, reduce environmental pollution, reduce costs, producing new products and engineered according to the increasing population. This review article provides an overview of the nanoparticles production in plants and their applications in agriculture, biotechnology, improved crops, and hazards of nanoparticles

Retinal Screening of Coats Disease Using Electroretinography

Background: Coats is a retinal disorder causing dilation of blood vessels in the human retina. The present study aims to measure electroretinography (ERG) in patients suffering from Coats disease. Material and Methods: 11 (20 eyes) male patients suffering from Coats were selected for the present study. Electroretinography was measured in the patient group using the Mangoni machine. The result was compared with the 11 (22 eyes) normal population following the ERG test. SPSS version 22 was used for this purpose. Results: The case and control groups were not significantly different in age, while a significant difference was observed in Best corrected visual acuity. BCVA between the two groups. Furthermore ( 110.9±8.63 and 93.09 ± 8.04 in control and case respectively ) , the difference between the mean amplitude of ERG, b wave was statistically significant as far as patient and normal groups were concerned.    Conclusion: Coats disease damages the retina, which can be measured by the amplitude of ERG, b wave

Determination of TOF characteristics in Iranian patients

Objective: Tetralogy of fallot (TOF) is one of the most common forms of cyanotic congenital heart disease (CHD). The aim of this study was determination of demography, associated anomalies, peripheral pulmonary stenosis (PPS), blood grouping, Rh typing, operation results and complications in TOF. Material & Methods: The records of 270 patients were reviewed. These patients were admitted from 1993 to 2003, in Shaheed Rajaei Hospital. Findings: Male patients were 60.37% and females were 39.63%. Incidence of patent foramen ovale (PFO), Right Aortic Arch (RAA), coronary artery (CA) anomalies and other anomalies were 44.81%, 21.11%, 9.25% and 36.30% respectively. Single ostium coronary artery (SOCA) was the most common CA anomaly. The most common PPS was bifurcation stenosis. TOF was more common in 0 blood group patients. The mean age at the first palliative operation was 5.21 years and for TC was 7.19 years. Post surgical mortality rate was about 3% and morbidity rate, 12.18%. Conclusion: Trend toward earlier total correction (TC), and single stage early TC of TOF should be recommended as the preferred management strategy