Sinusoidal Reference Technique for Power Factor Correction of a SEPIC Converter Fed from AC Supply

This paper presents a simple and efficient technique for power factor correction (PFC) and total harmonic distortion (THD) minimization of a SEPIC converter fed from AC supply. The performance of the SEPIC converter is studied through the power simulation program (PSIM) under different supply conditions with different loads. The obtained results have shown a very simple technique to obtain sinusoidal supply current at unity power factor with the different loads. Also, the proposed control technique can give sinusoidal supply current whatever the exciting supply contains harmonics or not

A Single-Phase Doubly-Excited DC-AC Buck-Boost Converter Suitable for Feeding AC Loads from PV Systems

This paper presents a new topology for converting a DC voltage to an AC one. The proposed converter is excited from two separate DC supplies so the term "Doubly-Excited". The most important features of the proposed converter are the output voltage (AC Voltage) is lower or higher than the input one (DC Voltage), controllable voltage and frequency, and the output voltage and current are approximately sinusoidal which means low harmonics content. Also, the paper presents the simulation of the proposed converter in different modes of operation under control to show the effectiveness of the proposed control. Keywords: Boost, Control, DC-AC Converter, Design, Simulation

Place evaluation: a transactional adaptive approach. The case study of Cairo's waterfront

The objective of this research is to determine how Cairenes construe places. The body of study is applied to the context of the waterfront area along the Nile River within Cairo. It is important to stress that the research is not based upon a witnessed well-defined problem but rather built upon a model, based upon a Transactional approach that explores how Cairenes construe places later revealing particular problems. A review of literature initially identifies many paradigms of perception and human behaviour. These paradigms have been used in order to identify a model, which is used to guide the course of the research and is based upon a man in environment perspective. Therefore the study is set out to individually determine aspects of place and human perception, bearing in mind the theoretical reasoning behind the model, which suggests that both entities should holistically be examined.The research is therefore orientated towards determining aspects of change between people and place. From an adaptation approach it is therefore argued that the level of variation existing within the environment determines the amount of change in behaviour and perception that may occur in order to achieve the appropriate balance required between people and place. As the research attempts to determine how Cairenes construe places, and as people's perceptions and the environment are in constant change, thus change in our case relates to how human perception and behaviour are affected by the level of variation existing within the environment. The basis of the model is therefore related to both context and human perception.The case study involves Cairo's waterfront as it is centrally located and considered as a convenient public place. This area is used in order to determine aspects of the context and human perception. Therefore the waterfront is considered as a public place used to examine the objectives of the research. The results reveal that there exists a lack of variation in public spaces along the waterfront and Cairo. It also highlights that the social class of people within a context affects how Cairenes' construe places. Both the contextual and perceptual analysis uncovers segregated patterns of behaviour within the City and is tackled by introducing general design recommendations for public areas situated along Cairo's waterfront and in general within public space.The methodology involves a qualitative analysis of interviews and a further quantitative analysis of a questionnaire. Both analyses attempt to determine dominant aspects of perception and context. It is also important to underline that within the proposed model derived from the Transactional approach, aspects of change are embodied in the level of variation existing within the environment. This is based upon the assumption that higher levels of variation in the context affect people's perceptions

Palladium(II) Complexes Containing Mixed Nitrogen-Sulphur Donor Ligands: Interaction of [Pd(Methionine Methyl Ester)(H 2

Pd(MME)Cl2 complex (MME = methionine methyl ester) was synthesised and characterized by physicochemical measurements. The reaction of [Pd(MME)(H2O)2]2+ with amino acids, peptides, or dicarboxylic acids was investigated at 25°C and 0.1 M ionic strength. Amino acids and dicarboxylic acids form 1 : 1 complexes. Peptides form both 1 : 1 complexes and the corresponding deprotonated amide species. The stability of the complexes formed was determined and the binding centres of the ligands were assigned. Effect of solvent on the stability constant of Pd(MME)-CBDCA complex, taken as a representative example, shows that the complex is more favoured in a medium of low dielectric constant. The concentration distribution diagrams of the complexes were evaluated

Generalized magneto-thermoelasticity in a perfectly conducting medium

AbstractA model of the equations of generalized magneto-thermoelasticity in a perfectly conducting medium is given. The formulation is applied to generalizations, Lord–Shulman theory with one relaxation time and the Green–Lindsay theory with two relaxation times, as well as to the coupled theory.Laplace transforms and Fourier transforms techniques are used to get the solution. The resulting formulation is used to solve a specific two-dimensional problem. The inverses of Fourier transforms are obtained analytically.Laplace transforms are obtained using the complex inversion formula of the transform together with Fourier expansion techniques.Numerical results for the temperature distribution, thermal stress and displacement components are represented graphically. A comparison was made with the results predicted by the three theories

Nanoemulsions in Food Industry

A great attention has been received in the last few years for nanotechnology applications in food as well as pharmaceutical industries. People are looking for healthy and safe food worldwide. Therefore, researchers have been currently focusing on nanoemulsion technology that is particularly suited for the production of functional food. This chapter includes an overview about nanoemulsion terminology and formulation, various approaches for production of nanoemulsions which include high energy approaches such as high-pressure valve homogenization, microfluidizers and ultrasonic homogenization, and low energy methods such as spontaneous emulsification, phase inversion composition, phase inversion temperature and emulsion inversion point. In addition, the applications of nanoemulsions in food industry are discussed in detail

Use of denaturing gradient gel electrophoresis in screening unknown β-thalassemia mutations in Egyptian patients

The molecular defects resulting in a β-thalassemia phenotype, in the Egyptian population show a clear heterogenic pattern. Many studies have embarked on the molecular detection and characterization of these mutations, using a wide array of the available techniques with successful detection of both known and unknown mutations. PCR based techniques, as well as direct DNA sequencing are effective with some limitations as regards the time, effort and high cost to reach a final diagnosis. Intermediary screening techniques have proved to be effective tools to overcome these drawbacks. This study aims to assess the use of the denaturing gradient gel electrophoresis (DGGE)1 to detect b-thalassemia mutations prior to the performance of direct sequencing to minimize the cost and workload involved in the process. In this study, forty-two previously genotyped patients in a study by El-Gawhary et al. in 2007, have been analyzed by DGGE for fragment 2 then 1. These are the β-globin gene fragments showing the majority of the β-thalassemia mutations. Sixty-eight alleles out of 79 mutant alleles in total were detected within these two fragments. The 11 undetected alleles comprise 9 alleles that require further examination using other DGGE fragments (0, 4 and 5) and correspond to -87(C > G), intervening sequence (IVS)II-1(G >A), IVS II-745, and IVS II-848(C > A). The remaining two that failed detection correspond to codon (CD) 37(G> A). Although, IVS-II 745(C >G) is undetectable within these two fragments, its 100% linkage polymorphism (+20 C> T) was detected in fragment 1 gel. DGGE is a sensitive technique to screen for β-thalassemia mutations. For simultaneous analysis of multiple samples with unknown mutations, it is recommended that direct DNA sequencing be coupled with DGGE whenever available to reduce time, effort and cost.Keywords: β-Thalassemia; DGGE; PCR; Mutations; Polymorphism; Screenin