A small scale energy harvester from wind induced vibrations

In this study, a new device for wind energy harvesting on a small-scale was proposed. This system is well suited for powering remote wireless sensors as a cheaper, more environmentally friendly alternative to conventional dry cell batteries which is a need that is being addressed by many recent research studies. The device consists of a cantilever beam with the free end attached to a square section box that is subjected to the air stream inducing aero-elastic flutter. Flutter is a coupled torsion, plunge instability that has been historically studied to be avoided by aerospace and civil engineers. A magnet is attached to the beam and a stationary coil is used to generate electrical power. A finite element model for the device was achieved by formulating a set of ordinary differential equations that integrate the mechanical model of the beam with the aero-elastic flutter of the square section at the tip and the electromagnetic effect of the energy harvesting coil, and they were numerically solved. Wind tunnel experiment runs were carried out for a system with a 30 cm beam and a 30 cm long 5cm wide cross section for wind speeds of 2.4 to 3.2 m/s and electric loads of 40© to 4M©. The numerical predictions were found to compare favorably with the experimental results in terms of the induced voltage, frequency, and power output

Evaluation of Vibration Amplitude Stepping and Welding Performance of 20 kHz and 40 kHz Ultrasonic Power of Metal Welding

Today ultrasonic power technique is consider a mandatory technique which is always entered in many processes such as in metal and plastic welding to overcomes many issues, with aided of applying force (pressure) and supplied high frequency vibration, a solid-state weld can be generated by ultrasonic metal welding technique. That gives a technique the ability to join not only a small component, whereas also to join thicker specimens, which depends on a proper control of matching welding conditions. Therefore a welding performance can be studied and compared after designed welding horn to resonance at frequencies of 20 kHz and 40 kHz. The analyses of the designed horn are completed through use a vibration mathematical expressions, modal and harmonic analyses to ensure the weldability due to applying ultrasonic power to the working area and also to compare the performance of joint at using two resonance frequencies of 20 kHz and 40 kHz. The dimensions of the horns were determined to match the selected resonance frequencies, which the lengths were calculated as 132 mm and 66 mm respectively. The analysis of the exciting model indicates that the axial vibration modes of 19,584 Hz and 39,794 Hz are obtained in 10th mode, while the two frequency values are recorded 19,600 Hz and 39,800 Hz from the frequency response of the two horns. The weld strength between Al and Cu specimens with a thickness 0.5 mm was evaluated using a tensile test, which the analyses were obtained under using different welding pressure and varied amplitudes. The results were recorded within exciting a horn with two different resonance frequencies, show the enhancement of weld strength and quality through control of stepping amplitude, the enhancement means obtain good strength of the weld, reduce sticking horn to specimen, and lower specimen marking

Enhancing information retrieval in folksonomies using ontology of place constructed from Gazetteer information

Dissertation submitted in partial fulfilment of the requirements for the Degree of Master of Science in Geospatial TechnologiesFolksonomy (from folk and taxonomy) is an approach to user metadata creation where users describe information objects with a free-form list of keywords (‘tags’). Folksonomy has have proved to be a useful information retrieval tool that support the emergence of “collective intelligence” or “bottom-up” light weight semantics. Since there are no guiding rules or restrictions on the users, folksonomy has some drawbacks and problems as lack of hierarchy, synonym control, and semantic precision. This research aims at enhancing information retrieval in folksonomy, particularly that of location information, by establishing explicit relationships between place name tags. To accomplish this, an automated approach is developed. The approach starts by retrieving tags from Flickr. The tags are then filtered to identify those that represent place names. Next, the gazetteer service that is a knowledge organization system for spatial information is used to query for the place names. The result of the search from the gazetteer and the feature types are used to construct an ontology of place. The ontology of place is formalized from place name concepts, where each place has a “Part-Of” relationship with its direct parent. The ontology is then formalized in OWL (Web Ontology Language). A search tool prototype is developed that extracts a place name and its parent name from the ontology and use them for searching in Flickr. The semantic richness added to Flickr search engine using our approach is tested and the results are evaluated

Effect of Sildenafil Citrate on Success Rate of Ovulation Induction by Clomiphene Citrate

Background: Disorders of ovulation are common causes of infertility, and polycystic ovary syndrome (PCOS) is by far the most frequent condition. Objetive: The aim of this work was to evaluate the effect of adding vaginal sildenafil citrate to clomophine citrate used as ovarian stimulant drug on both endometrial thickness and pregnancy rate in patient with polycystic ovary syndrome (PCO). Patients and Methods: This prospective Comparative study included a total of 58 patients with primary and secondary infertility aged between18 years to 35 years, attending at Outpatient Clinics, Obstetrics and Gynecology Department, Zagazig University Hospitals. Patients were divided into two equal groups; each were 29. 1st Group was given clomiphene, and 2nd group was given Clomophine citrate and Sildenafil. A transvaginal Scan for imaging the uterus and adnexa for any pathology and measuring the basic endometrial thickness was also done on Day 3. Results: This study shows that there was an increase in endometrial thickness in sildenafil group (13.4±1.814 mm) comparable with clomiphene citrate group only (8.52±2.081 mm) (P=0.01). The result was statistically significant with increase threshold regard for implantation with statistically significant in group B (P=0.018). Conclusions: It could be concluded that addition of sildenafil citrate to clomiphene citrate therapy for induction of ovulation in patients with PCOS resulted in significant increase of endometrial thickness and non-significant increase of pregnancy Rates

Craniofacial And Dental Arches Characteristics In Transfusion Dependent Thalassaemia Patients

Penyakit talasemia merupakan penyakit yang biasa di Asia Tenggara. Namun maklumat berkaitan dengan deformasi kraniofasial dan lengkungan gigi serta kerencatan dalam proses pematangan tulang, amatlah terhad. Tujuan kajian ini adalah untuk menentukan prevalen kecacatan kraniofasial pesakit talasemia transfusi dependen (TDT) dan hubungan antara kecacatan ini dengan data klinikal. Kajian ini juga adalah untuk membandingkan ukuran sepalometrik, lengkungan gigi dan kematangan tulang vertebra servikal di kalangan pesakit talasemia transfusidependen dengan kumpulan biasa kawalan. Thalassaemia diseases are common in Southeast Asia. However, information about craniofacial and dental arches deformity as well as retardation of skeletal maturation are deficient in this area. The aims of this study were to determine the prevalence of craniofacial deformity (CFD) in transfusion-dependent thalassaemia (TDT) patients and the association between this deformity and clinical data. It was also to compare cephalometric measurements, dental arches features and cervical vertebral maturation of TDT with a normal control group