Effect of dental implant micro-thread designs on stress distribution in bone-implant interface

Dental implants have been used in replacing broken or damaged teeth. There are failures after the operation was done due to lack of primary stability. Through improving the design of the dental implant, primary stability can be achieved. The aim of the study is to analyse the stress distribution at bone-implant interface due to different micro-thread designs. Five types of two-dimension micro-thread shapes dental implant embedded in bone cube are modeled in ANSYS APDL R3. The micro-thread shapes are Straight, Square, V-shaped, Buttress and Reverse Buttress. The models are meshed using element Quad 8-node 183. 106.066N of horizontal force and vertical force are applied on each model to find out the stress distribution pattern and peak Von Mises stress. The study found that micro-thread shapes changed the stress distribution on implant and bone. The peak Von Mises stress was located at the first micro-thread. Cortical bone took large portion of stress compared to cancellous bone. Square micro-thread has the best stress distribution pattern

Stochastic multi-scale analysis of homogenised properties considering uncertainties in cellular solid microstructures using a first-order perturbation

Randomness in the microstructure due to variations in microscopic properties and geometrical information is used to predict the stochastically homogenised properties of cellular media. Two stochastic problems at the micro-scale level that commonly occur due to fabrication inaccuracies, degradation mechanisms or natural heterogeneity were analysed using a stochastic homogenisation method based on a first-order perturbation. First, the influence of Young's modulus variation in an adhesive on the macroscopic properties of an aluminium-adhesive honeycomb structure was investigated. The fluctuations in the microscopic properties were then combined by varying the microstructure periodicity in a corrugated-core sandwich plate to obtain the variation of the homogenised property. The numerical results show that the uncertainties in the microstructure affect the dispersion of the homogenised property. These results indicate the importance of the presented stochastic multi-scale analysis for the design and fabrication of cellular solids when considering microscopic random variation

Quantitative sex identification of hatchling green sea turtles (Chelonia mydas)

The histological characteristics of the gonads and paramesonephric ducts were investigated to allow a quantitative distinction among male, female, and intersex hatchling Green Sea Turtles (Chelonia mydas) from peninsular Malaysia. Hatchling sexes were identified initially as either males or females based on the incubation temperatures, and intersex hatchlings were collected from in situ nests. Traditionally, this assignment is confirmed by qualitative visual assessment of histological sections of the gonads and paramesonephric ducts. We describe a quantitative method for measuring these parameters to distinguish hatchling sex. The thickness of the paramesonephric duct epithelium area, the height of the nucleus in cells within the gonadal cortical epithelium, and the width of the gonadal ridge were measured in sections from 116 hatchlings. Upon examination of the histological material, hatchlings identified initially by incubation temperature as females were found to have significantly thicker paramesonephric duct epithelium and greater gonadal ridge width and cortical epithelium nuclear height compared with hatchlings identified as males. In addition, some hatchlings demonstrated histological characteristics of both sexes (designated here as intersex hatchlings) in some or all of the traditional histological sexing criteria. The "intersex" group could be divided into two subgroups by the quantitative measurements described here. Using this method, hatchlings could be classified as either males, females, or intersexes with a male-appearing gonad and female-appearing duct or a female-appearing gonad and male-appearing duct. The method outlined here provides a quantitative way to distinguish sex and provides insight in intersex grouping in hatchling C. mydas

Development of Wireless Safety System for Hybrid Vehicle Hazard Monitoring

The advent of advanced automobile technology has enabled the introduction of hybrid vehicle engine which is a combination of electric motor and gasoline fuel usage. Although the technology seems to support environment and provide ease of use to the consumer, the underlying risk associated with this is electrocution which could be fatal with the high rating of battery used in these vehicles. To minimise such risk, an economical and efficient monitoring system has been designed and developed to monitor voltage and current leakage from related cables on hybrid vehicles and warned stakeholders when the event necessitates it. Data collected shows alarming potential current leakage characteristic on overused cables when analysed