The Dynamic Modelling and Electrical Profiles of Three Phase Induction Motor Using MATLAB Program

This paper addresses the dynamic behaviour of 3-? induction machines based on a quality mathematical model and computer program simulation in a stationary reference frame to avoid the complexity involved in the course of solving time-varying differential equations obtained from the dynamic model. Laplace transform of the dynamic equations was carried out to derive analytical solutions the current variables.  4th 0rder Runge-Kutta method is adopted to give numerical solution of the dynamic model. The basic electrical characteristics of the 3-? induction machine are considered in the two-phase approximate equivalent model. The graphical curves were obtained from MATLAB program code developed. Keywords: 3-? Induction Machines, Dynamic Model, Reference Frame, ??-Coordinate, Analytical and Numerical Solution, MATLAB program cod

Locally Advanced Orofacial Malignancy: Synopsis of Inoperable Lesions at an Urban Tertiary Health Facility in Nigeria

Background: Locally advanced inoperable orofacial malignancies do present clinically, and constitute a significant public health burden worldwide. Objective: To determine the prevalence and clinical characteristics of Stage IV locally advanced inoperable orofacial malignancies for consecutive patients. Materials and Methods: A 24‑year retrospective study was undertaken, and data obtained from hospital register, case files, and histopathological  reports of patients were recorded in a proforma. The variables studied were age, sex, type of lesion and site, duration of lesion, tobacco/alcohol use, and socioeconomic status of the patients and clinical features of the lesions. Results: Twenty‑six patients presented, giving a prevalence of 11.2%. The most common lesion was adenoid cystic carcinoma, 23.1%. Males accounted for 18 (69.2%) cases and females, 8 (30.8%) giving a male to female ratio of 2.3:1. The ages ranged from 21 to 65 years, mean (SD) 48.6 (7.3) years. The gender distribution was clinically and statistically significant in favor of the males (P = 0.001). The patients were in the low socioeconomic class and 20 (76.9%) indulged in chronic use of tobacco and alcohol. The duration of the lesions ranged from 1.8 to 3.1 years. The maxilla/facial skin was the commonest site (46.2%). Clinically and statistically, the relativity of site distribution of lesions was significant (P = 0. 002). The clinical features occurred in combination resulting in an average of 10 symptoms and  signs in each patient. Conclusion: The synopsis of these lesions shows that all have undergone metastasis; salivary gland malignancies were most common with maxilla  as the commonest site. Keywords: Inoperable, locally advanced, malignancy, orofacial, synopsi

Prevention of alveolar osteitis after third molar surgery: Comparative study of the effect of warm saline and chlorhexidine mouth rinses

Background: Chlorhexidine mouth rinses have a proven efficacy for the prevention of alveolar osteitis after third molar surgery. This study compares the efficacy of warm saline rinse, a component of postextraction instructions, with that of chlorhexidine in our institution over a period of 2 years.Patients and Methods: Apparently healthy patients who were referred to the Oral Surgery Clinic of our institution, with an indication for surgical extraction of lower third molar were prospectively, consecutively, and uniformly randomized into warm saline and chlorhexidine groups. The experimental group (n = 50/100) were instructed to gargle twice daily with warm saline, whereas the chlorhexidine group (n = 50/100) were instructed to gargle with 0.12% chlorhexidine. Information on demographic, types and level of impaction, indications for extraction, and development of alveolar osteitis were obtained and analyzed. Comparative statistics were done using Pearson’s Chi-square, Fisher’s exact, or Mann–Whitney U-tests as appropriate. P <0.05 was considered statistically significant.Results: The demographic, types and level of impaction as well as indications for extractions were comparable between the study groups (P > 0.05). The overall prevalence of alveolar osteitis was 5%. There was no statistically significant difference between application of warm saline and 0.12% chlorhexidine rinse with respect to the development of alveolar osteitis (P = 0.648).Conclusion: Warm saline mouth rinse is equally as effective as chlorhexidine mouth rinse, as prophylaxis against prevention of alveolar osteitis after third molar surgery.Keywords: Alveolar osteitis, chlorhexidine, prevention, warm salin