Design of LLC resonant converter with silicon carbide MOSFET switches and nonlinear adaptive sliding controller for brushless DC motor system

Introduction. The high voltage gain DC-DC converters are increasingly used in many power electronics application systems, due to their benefits of increased voltage output, reduced noise contents, uninterrupted power supply, and ensured system reliability. Most of the existing works are highly concentrated on developing the high voltage DC-DC converter and controller topologies for goal improving the steady state response of brushless DC motor driving system and also obtain the regulated voltage with increased power density and reduced harmonics, the LLC resonant DC-DC converter is implemented with the silicon carbide MOSFET switching devices Problem. Yet, it facing the major problems of increased switching loss, conduction loss, error outputs, time consumption, and reduced efficiency. Also the existing works are mainly concentrating on improving the voltage gain, regulation, and operating performance of the power system with reduced loss of factors by using the different types of converters and controlling techniques. The goal of this work is to obtain the improved voltage gain output with reduced loss factors and harmonic distortions. Method. Because, this type of converter has the ability to generate the high gain DC output voltage fed to the brushless DC motor with reduced harmonics and loss factors. Also, the nonlinear adaptive sliding controller is implemented to generate the controlling pulses for triggering the switching components properly. For this operation, the best gain parameters are selected based on the duty cycle, feedback DC voltage and current, and gain of silicon carbide MOSFET. By using this, the controlling signals are generated and given to the converter, which helps to control the brushless DC motor with steady state error. Practical value. The simulation results of the proposed LLC silicon carbide MOSFET incorporated with nonlinear adaptive sliding controller controlling scheme are validated and compared by using various evaluation indicators. Вступ. Високовольтні перетворювачі постійного струму з високим коефіцієнтом посилення напруги все частіше використовуються в багатьох прикладних системах силової електроніки через їх переваги, пов'язані з підвищеною вихідною напругою, зниженим рівнем шуму, безперебійним живленням і гарантованою надійністю системи. Більшість існуючих робіт значною мірою зосереджені на розробці топологій високовольтного перетворювача постійного струму і контролера з метою поліпшення усталеного відгуку системи приводу безщіткового двигуна постійного струму, а також отримання регульованої напруги з підвищеною щільністю потужності і зменшеними гармоніками; резонансний LLC-перетворювач постійного струму, реалізований на перемикаючих пристроях на основі польових МОП-транзисторах з карбіду кремнію. Проблема. Тим не менш, це стикається з основними проблемами, пов'язаними зі збільшенням втрат при перемиканні, втратами провідності, помилками на виході, витратами часу та зниженням ефективності. Крім того, існуючі роботи в основному зосереджені на покращенні коефіцієнта посилення напруги, регулювання та робочих характеристик енергосистеми із зменшенням факторів втрат за рахунок використання різних типів перетворювачів та методів управління. Метою роботи є отримання покращеного коефіцієнта посилення напруги зі зниженими коефіцієнтами втрат і гармонійних спотворень. Метод. Таким чином, цей тип перетворювача здатний генерувати вихідну постійну напругу з високим коефіцієнтом посилення, що подається на безщітковий двигун постійного струму, зі зменшеними коефіцієнтами гармонік та втрат. Крім того, реалізований нелінійний адаптивний ковзний регулятор для генерування керуючих імпульсів для належного спрацьовування перемикаючих компонентів. Для цієї операції вибираються найкращі параметри посилення на основі робочого циклу, постійної напруги та струму зворотного зв'язку, а також коефіцієнта посилення польового МОП-транзистора з карбіду кремнію. При цьому керуючі сигнали генеруються і передаються на перетворювач, який допомагає керувати безщітковим двигуном постійного струму з помилкою, що встановилася. Практична цінність. Результати моделювання запропонованого LLC-перетворювача на основі польових МОП-транзисторів з карбіду кремнію зі схемою управління нелінійним адаптивним ковзним регулятором перевіряються та порівнюються з використанням різних показників оцінки.&nbsp

A Study to Evaluate the Effectiveness of Information Education and Communication (IEC) on Knowledge Regarding Prevention of Urinary Tract Infection among Adolescent Girls in a Selected School at Valparai, Coimbatore

The present study was to evaluate the effectiveness of information education and communication on knowledge regarding prevention of urinary tract infection among adolescent girls in a selected school at Valparai. The objectives of the study were, To assess the pre-test and post-test knowledge regarding prevention of urinary tract infection among adolescent girls. To evaluate the effectiveness of Information Education and Communication on the prevention of urinary tract infection among adolescent girls. To determine the association between the level of knowledge regarding prevention of urinary tract infection among adolescent girls with their selected demographic variables. A quasi-experimental design was chosen for this study. The randomized sampling technique was used to select the samples based on inclusion and exclusion criteria. Sample size was 150. Structured self administered knowledge questionnaire was used to collect the data from research subjects. It consisted of two sections. Section I - Demographic variables of adolescent girls. Section II - Structured self administered knowledge questionnaire to assess the level of knowledge regarding prevention of urinary tract infection. The content validity was done by experts in the field of nursing. Data collection was done by using the structured self administered knowledge questionnaire, followed by that Information Education and Communication (IEC) on knowledge regarding prevention of urinary tract infection was given for 45 minutes on the same day. After an interval of 5 days, again a structured self administered knowledge questionnaire was administered to assess the post-test level of knowledge on the 6th day. The hypotheses for the study were H1- There is a significant difference between mean pre-test and post-test level of knowledge regarding prevention of urinary tract infection among adolescent girls in a selected school at Valparai. H2-There is a significant association between post-test score on level of knowledge regarding prevention of urinary tract infection among adolescent girls with their selected demographic variables. The collected data was analyzed by using descriptive statistics (mean, frequency, percentage and standard deviation) and inferential statistics (paired’t’ test and chi square test and results were drawn. MAJOR FINDINGS OF THE STUDY Among the 150 adolescent girls, the majority of the samples 50(33.3%) were in the age group of 15 years,106(70.7%) of the samples were in the religion of Hindu, samples mother 43(28.7%) were completed middle school, samples father 44(29.3%) were completed middle school, half proportion of samples 87(58%) were in nuclear family, half proportion of samples 114(76%) in living rural area, most of the samples 105(70%) were not got information, and higher proportion of samples 99(66%) have not previous history of urinary tract infection. In pre-test knowledge regarding prevention of urinary tract infection among 150 adolescent girls 35(23.3%) had inadequate knowledge, 101(67.3%) had moderately adequate knowledge, 14(9.3%) had adequate knowledge. Study finding revealed that majority of adolescent girls had moderate knowledge regarding prevention of urinary tract infection. So, there is need of educational programme to the adolescent girls regarding prevention of urinary tract infection. In post-test level of knowledge regarding prevention of urinary tract infection among 150 adolescent girls, majority of 124(82.7%) had adequate knowledge and 26(17.3%) had moderately adequate knowledge. Thus, it revealed that there was a significant difference between the pre-test and post-test score of knowledge regarding prevention of urinary tract infection among adolescent girls. With regard to effectiveness of Information Education and Communication (IEC) on knowledge regarding prevention of urinary tract infection the pre-test knowledge mean score was 14.1 and standard deviation 5.62. The post-test mean score was 25.5 and standard deviation 3.2 and which increased after Information Education and Communication intervened the calculated mean deviation was 11.4 and ‘t’ value was 27.00, which was statistically significant at p<0.05 level. Thus, it was inferred that the IEC progamme was effective in improving adolescent girls’ knowledge regarding prevention of urinary tract infection. With regard to the association between the pre-test and post-test level of knowledge regarding prevention of urinary tract infection among adolescent girls with their demographic variables. The study finding revealed that there was significant association between the level of knowledge and age, education of the father, type of family, area of living and previous history. These have a significant association between the knowledge regarding prevention of urinary tract infection among adolescent girls. CONCLUSION The main conclusion drawn from the present study was that most of the adolescent girls had inadequate level of knowledge regarding prevention of urinary tract infection. After information education and communication, it was found that they had significantly improved in level of knowledge regarding prevention of urinary tract infection among adolescent girls. Samples became familiar and found themselves comfortable and also expressed satisfaction. The study revealed that through Information Education and Communication (IEC) they know about what is urinary tract infection and also this information can be communicated to others, to prevent urinary tract infection in the family and community. Thus, it was concluded that, Information Education and Communication on prevention of urinary tract infection among adolescent girls was effective to improve the level of knowledge. NURSING IMPLICATIONS According to Tolsme, (1995) the section of the research report that focuses on the nursing implications usually included specific suggestions for nursing practice, nursing education, nursing research and nursing administration. Nursing implications usually includes specific suggestions for nursing practice, nursing education, nursing research and nursing administration. Nursing implications in this study are enlisted below NURSING PRACTICE Nurses can learn to assess knowledge regarding prevention of urinary tract infection by using structured self administered questionnaire on adolescent girls and magnify the importance to plan out the programme depending on the needs of adolescent girls in various settings. Nurses can learn accurate assessment of knowledge regarding prevention of urinary tract infection by using structured questionnaire among adolescent girls and magnify the importance to plan out the programmes depending upon the need of the girls in various setting. Nurses play an important role in providing primary care for urinary tract infection and also giving health education regarding prevention. The impact of formulating and implementing steps on primary prevention of urinary tract infection by nursing personnel. The nurse motivates the adolescent girls to utilize the health care services to improve health. NURSING EDUCATION Educate the nursing personnel to update their knowledge and skills in assessing the adolescent girls. Prepare the nursing students to develop the skills in identifying the symptoms and signs of urinary tract infection among adolescent girls. Nurses have to update their knowledge regarding prevention of urinary tract infection by participating and listening to programmes in various settings. NURSING ADMINISTRATION Nurse administration has to make provision to promote health education with Audio Visual aids regarding prevention of urinary tract infection. In-service education program and continuing education programme can be conducted for the nurses on this specialization with urinary tract infection to update their knowledge. The nurse administration should provide necessary facilities to equip the staff to focus on preventive, promotive and curative aspect of care regarding prevention of urinary tract infection. Nurse administrator should motivate the nurses to conduct the mass education programme in the school and community area regarding prevention of urinary tract infection. Collaborate with hospital administration in policies and employ the specially trained nurses who needed knowledge for the prevention of urinary tract infection. NURSING RESEARCH Adds to the research review about the importance of prevention for urinary tract infection among adolescent girls. Conduct further research in a different setting by using the above findings as a baseline data to expand the scientific body of professional knowledge. Disseminated the finding through journals and publications. The findings will help in the practice aspect to expand the role of nurse. LIMITATIONS The study was confined to a specific geographical area only by selecting a Government Girls Higher Secondary School, Valparai, which imposes limits to any large generalization. The study was limited only to adolescent girls and the groups were small which resulted in reduced power in statistical analysis. 64 The data was collected from 150 samples to find out the awareness. It could be done on more samples for the larger generalization. RECOMMENDATIONS A similar study can be conducted for a larger group of adolescent girls. A similar study can be conducted with a true experimental design. The same study can be conducted in a different setting such as a hospital. A comparative study can be done regarding prevention of urinary tract infection between girls from a private and a government school

A Novel Approach for Integrated Shortest Path Finding Algorithm (ISPSA) Using Mesh Topologies and Networks-on-Chip (NOC)

A novel data dispatching or communication technique based on circulating networks of any network IP is suggested for multi data transmission in multiprocessor systems using Networks-On-Chip (NoC). In wireless communication network management have some negatives have heavy data losses and traffic of data sending data while packet scheduling and low performance in the varied network due to workloads. To overcome the drawbacks, in this method proposed system is Integrated Shortest Path Search Algorithm (ISPSA) using mesh topologies. The message is sent to IP (Internet Protocol) in the network until the specified bus accepts it. Integrated Shortest Path Search Algorithm for communication between two nodes is possible at any one moment. On-chip wireless communications operating at specific frequencies are the most capable option for overcoming metal interconnects multi-hop delay and excessive power consumption in Network-on-Chip (NoC) devices. Each node can be indicated by a pair of coordinates (level, position), where the level is the tree's vertical level and the view point is its horizontal arrangement in the sequence of left to right. The output gateway node's n nodes are linked to two nodes in the following level, with all resource nodes located at the bottommost vertical level and the constraint of this topology is its narrow bisection area. The software Xilinx 14.5 tool by using that overall performance analysis of mesh topology, each method are reduced data losses with better accuracy although the productivity of the delay is decreased by 21 % was evaluated and calculated.

Nonlinear reconfiguration for asymmetric failures in a six degree-of-freedom F-16

Proceedings, American Control Conference, pp 1823-1828. Retrieved April 2006 from http://www.pages.drexel.edu/~hgk22/OnlinePubs/Thomas%20Kwatny%20Chang%20ACC04%200326_WeP15.6.pdf.In this paper we consider an F-16 fighter aircraft subject to asymmetric actuator failures. To address nonsymmetric faults it is not possible to decouple the longitudinal and lateral dynamics. It is necessary to deal with a full six degree of freedom airframe. First, we outline an automated procedure to assemble symbolic and simulation models of complex aircraft. The symbolic model can be manipulated in various ways and used for both linear and nonlinear control system design. In the event of actuator failures, the failed surfaces not only cease to function as viable inputs but also impose persistent disturbances on the system. As previously shown, the problem of designing a reconfigured controller can be formulated as a nonlinear disturbance rejection problem. We apply this method to design a controller for the F-16

Bifurcation analysis of flight control systems

Proceedings International Federation of Automatic Control Triennial World Congress, Prague, July 2005. Retrieved April 2006 from http://www.pages.drexel.edu/~hgk22/OnlinePubs/Thomas%20Kwatny%20Chang%20IFAC%202005.pdfHigh performance systems, like the F-16, when pushed to their limits encounter qualitative changes in control system properties like loss of controllability or observability. This work identifies and characterizes bifurcations occurring in a nonlinear six degree of freedom F-16 in two scenarios - straight and level flight and in a coordinated turn. Phenomena such as stall, tumbling and spin-roll departure were observed around bifurcation points. This work provides a basis for a formal understanding of how aircraft depart from controlled flight, it is a prerequisite for the systematic design of recovery strategies, and it will contribute to the design of reconfigurable control of impaired aircraft

A Fibreoptic Endoscopic Study of Upper Gastrointestinal Bleeding at Bugando Medical Centre in Northwestern Tanzania: a Retrospective Review of 240 Cases.

Upper gastrointestinal (GI) bleeding is recognized as a common and potentially life-threatening abdominal emergency that needs a prompt assessment and aggressive emergency treatment. A retrospective study was undertaken at Bugando Medical Centre in northwestern Tanzania between March 2010 and September 2011 to describe our own experiences with fibreoptic upper GI endoscopy in the management of patients with upper gastrointestinal bleeding in our setting and compare our results with those from other centers in the world. A total of 240 patients representing 18.7% of all patients (i.e. 1292) who had fibreoptic upper GI endoscopy during the study period were studied. Males outnumbered female by a ratio of 2.1:1. Their median age was 37 years and most of patients (60.0%) were aged 40 years and below. The vast majority of the patients (80.4%) presented with haematemesis alone followed by malaena alone in 9.2% of cases. The use of non-steroidal anti-inflammatory drugs, alcohol and smoking prior to the onset of bleeding was recorded in 7.9%, 51.7% and 38.3% of cases respectively. Previous history of peptic ulcer disease was reported in 22(9.2%) patients. Nine (3.8%) patients were HIV positive. The source of bleeding was accurately identified in 97.7% of patients. Diagnostic accuracy was greater within the first 24 h of the bleeding onset, and in the presence of haematemesis. Oesophageal varices were the most frequent cause of upper GI bleeding (51.3%) followed by peptic ulcers in 25.0% of cases. The majority of patients (60.8%) were treated conservatively. Endoscopic and surgical treatments were performed in 30.8% and 5.8% of cases respectively. 140 (58.3%) patients received blood transfusion. The median length of hospitalization was 8 days and it was significantly longer in patients who underwent surgical treatment and those with higher Rockall scores (P < 0.001). Rebleeding was reported in 3.3% of the patients. The overall mortality rate of 11.7% was significantly higher in patients with variceal bleeding, shock, hepatic decompensation, HIV infection, comorbidities, malignancy, age > 60 years and in patients with higher Rockall scores and those who underwent surgery (P < 0.001). Oesophageal varices are the commonest cause of upper gastrointestinal bleeding in our environment and it is associated with high morbidity and mortality. The diagnostic accuracy of fibreoptic endoscopy was related to the time interval between the onset of bleeding and endoscopy. Therefore, it is recommended that early endoscopy should be performed within 24 h of the onset of bleeding

Derivation and validation of a risk-factor model for detection of oral potentially malignant disorders in populations with high prevalence

Background:Oral and pharyngeal cancers constitute the sixth most common type of cancer globally, with high morbidity and mortality. In many countries, most cases of oral cancer arise from long-standing, pre-existing lesions, yet advanced malignancies prevail. A new approach to early detection is needed. We aimed to validate a model for screening so that only high-risk individuals receive the clinical examination.Methods:A community-based case-control study (n1029) in rural Sri Lanka assessed risk factors and markers for oral potentially malignant disorders (OPMD) by administering a questionnaire followed by an oral examination. We then developed a model based on age, socioeconomic status and habits of betel-quid chewing, alcohol drinking and tobacco smoking, with weightings based on odds ratios from the multiple logistic regression. A total, single score was calculated per individual. Standard receiver-operator characteristic curves were plotted for the total score and presence of OPMD. The model was validated on a new sample of 410 subjects in a different community.Results:A score of 12.0 produced optimal sensitivity (95.5%), specificity (75.9%), false-positive rate (24.0%), false-negative rate (4.5%), positive predictive value (35.9%) and negative predictive value (99.2%).Conclusion:This model is suitable for detection of OPMD and oral cancer in high-risk communities, for example, in Asia, the Pacific and the global diaspora therefrom. A combined risk-factor score of 12.0 was optimal for participation in oral cancer/OPMD screening in Sri Lanka. The model, or local adaptations, should have wide applicability

Reconstructive periodontal therapy with simultaneous ridge augmentation. A clinical and histological case series report

Treatment of intrabony periodontal defects with a combination of a natural bone mineral (NBM) and guided tissue regeneration (GTR) has been shown to promote periodontal regeneration in intrabony defects. In certain clinical situations, the teeth presenting intrabony defects are located at close vicinity of the resorbed alveolar ridge. In these particular cases, it is of clinical interest to simultaneously reconstruct both the intrabony periodontal defect and the resorbed alveolar ridge, thus allowing insertion of endosseous dental implants. The aim of the present study was to present the clinical and histological results obtained with a new surgical technique designed to simultaneously reconstruct the intrabony defect and the adjacently located resorbed alveolar ridge. Eight patients with chronic advanced periodontitis displaying intrabony defects located in the close vicinity of resorbed alveolar ridges were consecutively enrolled in the study. After local anesthesia, mucoperiosteal flaps were raised, the granulation tissue removed, and the roots meticulously scaled and planed. A subepithelial connective tissue graft was harvested from the palate and sutured to the oral flap. The intrabony defect and the adjacent alveolar ridge were filled with a NBM and subsequently covered with a bioresorbable collagen membrane (GTR). At 11–20 months (mean, 13.9 ± 3.9 months) after surgery, implants were placed, core biopsies retrieved, and histologically evaluated. Mean pocket depth reduction measured 3.8 ± 1.7 mm and mean clinical attachment level gain 4.3 ± 2.2 mm, respectively. Reentry revealed in all cases a complete fill of the intrabony component and a mean additional vertical hard tissue gain of 1.8 ± 1.8 mm. The histologic evaluation indicated that most NBM particles were surrounded by bone. Mean new bone and mean graft area measured 17.8 ± 2.8% and 32.1 ± 8.3%, respectively. Within their limits, the present findings indicate that the described surgical approach may be successfully used in certain clinical cases to simultaneously treat intrabony defects and to reconstruct the resorbed alveolar ridge