Review Paper on Road Vehicle Vibration Simulation for Packaging Testing Purposes

Inefficient packaging constitutes a global problem that costs hundreds of billions of dollars, not to mention the additional environmental impacts. An insufficient level of packaging increases the occurrence of product damage, while an excessive level increases the packages' weight and volume, thereby increasing distribution cost. This problem is well known, and for many years, engineers have tried to optimize packaging to protect products from transport hazards for minimum cost. Road vehicle shocks and vibrations, which is one of the primary causes of damage, need to be accurately simulated to achieve optimized product protection. Over the past 50 years, road vehicle vibration physical simulation has progressed significantly from simple mechanical machines to sophisticated computer-driven shaking tables. There now exists a broad variety of different methods used for transport simulation. Each of them addresses different particularities of the road vehicle vibration. Because of the nature of the road and vehicles, different sources and processes are present in the vibration affecting freight. Those processes can be simplified as the vibration generated by the general road surface unevenness, road surface aberrations (cracks, bumps, potholes, etc.) and the vehicle drivetrain system (wheels, drivetrain, engine, etc.). A review of the transport vibration simulation methods is required to identify and critically evaluate the recent developments. This review begins with an overview of the standardized methods followed by the more advanced developments that focus on the different random processes of vehicle vibration by simulating non-Gaussian, non-stationary, transient and harmonic signals. As no ideal method exists yet, the review presented in this paper is a guide for further research and development on the topic

Oral maxillofacial neoplasms in an East African population a 10 year retrospective study of 1863 cases using histopathological reports

<p>Abstract</p> <p>Background</p> <p>Neoplasms of the oral maxillofacial area are an interesting entity characterized by differences in nomenclature and classification at different centers.</p> <p>We report neoplastic histopathological diagnoses seen at the departments of oral maxillofacial surgery of Muhimbili and Mulago referral hospitals in Tanzania and Uganda respectively over a 10-year period.</p> <p>Methods</p> <p>We retrieved histopathological reports archived at the departments of oral maxillofacial surgery of Muhimbili and Mulago referral hospitals in Tanzania and Uganda respectively over a 10-year period from June 1989–July 1999.</p> <p>Results</p> <p>In the period between June 1989 and July 1999, 565 and 1298 neoplastic oro-facial cases were retrieved of which 284 (50.53%) and 967 (74.54%) were malignant neoplasms at Muhimbili and Mulago hospitals respectively. Overall 67.28% of the diagnoses recorded were malignant with Kaposi's sarcoma (21.98%), Burkiits lymphoma (20.45%), and squamous cell carcinoma (15.22%) dominating that group while ameloblastoma (9.23%), fibromas (7.3%) and pleomorphic adenoma (4.95%) dominated the benign group.</p> <p>The high frequency of malignancies could be due to inclusion criteria and the clinical practice of selective histopathology investigation. However, it may also be due to higher chances of referrals in case of malignancies.</p> <p>Conclusion</p> <p>There is need to reexamine the slides in these two centers in order to bring them in line with the most recent WHO classification so as to allow for comparison with reports from else where.</p