Background: Dental anomalies might occur due to abnormal events during teeth development caused by environmental or genetic factors during histo differentiation or morph differentiation stages of embryological development. Aims of the study: To evaluate the distribution of developmental dental anomalies according to age and gender in relation to nutritional status in children attending College of Dentistry /University of Baghdad. Materials and method: After examination 5760 children aged 5-12 years of both genders only 147child with dental anomalies were found, all developmental dental anomalies that were clinically observable were recorded. The developmental dental anomalies which diagnosed in this study were supernumerary, missing teeth, talon cusp, microdontia, gemination, fusion, peg shape lateral, enamel hypoplasia, dentinogenesis imperfacta and amelodensis imperfacta. Nutritional status for each child assessed by measuring weight and height to calculate body mass index. Results: The results of the current study showed that the supernumerary teeth was the first most common anomaly seen in this study followed by localized hypoplasia which the second most common anomaly seen followed by missing teeth and microdontia respectively. Regarding total sample from 5 to 12 years old children, the findings showed that the children percent with number anomalies (42.9%) was highest than children percent with structural anomalies and shape anomalies (32.7%, and 24.5% respectively) with statistically highly significant difference (P<0.01). The shape anomalies and structural anomalies percent (25.0%, and 40.0% respectively) were higher among girls than boys while number anomalies percent (48.3%) was higher among boys than girls with non significant difference (P>0.05). The results showed that the underweight children showed higher percent (53.1%) among all age groups than children who were normal weight, over weight and obese (32.7%, 12.2%, and 2.0% respectively) with highly significant difference (P< 0.01). The results illustrated that both boys and girls showed highest percent of underweight (44.8%, and 65.0% respectively) followed by normal weight, over weight and obese with statistically non significant difference. The results also reported that the underweight children presented with highest shape and structural anomalies percent (75.0%, and 50.0% respectively) except number anomalies showed highest percent (47.6%) among normal weight children. Regarding total sample, the underweight children presented with highest dental anomalies percent of all anomalies types(53.1%)than normal weight, over weight and obese children with highly significant difference ( P< 0.01). Conclusion: The present study showed the association of nutritional status with dental anomalies among Iraqi children.
Recently, environmental noise has arisen from various sources, such as those from exhaust mufflers of combustion engines found in cars, trucks, or power generators, which produce significant noise during their operation. Controlling the radiated noise from these mufflers is a major factor in improving acoustic comfort and minimizing the impact on the surrounding communities. Numerous research has been presented for this reason by modification of the internal structure of the exhaust muffler. The main objective of this work is to reduce the noise level emitted from exhaust mufflers. This can be achieved by adjusting structure parameters to attenuate the surrounding environment's radiated noise. Analysis of pressure-wave propagation h
... Show More
(2)
(1)
(12)
(6)
(1)
(9)
(9)
One of the most important phenomenon that occurs in sheet metal forming processes is the spring-back, which causes several geometrical alterations in the parts. The accurate prediction of springback after bending unloading is the key to the tool design, operation control, and precision estimate concerning the part geometry. This study investigated experimentally the effect of pretension in three rolling direction (0, 90, 45 degree) on the springback behavior of the yellow brass, sheet under V shape bending die. The pre-tension ranges from five different levels starting of 11% to 55% from the total strain in each rolling direction by regular increase of 11 %, then bent on a V-die 90 degree for the springback estimate. From experiment the
... Show MoreThermal conductivity measurement was done for specimens of Polystyrene/ titanium dioxide, Polycarbonate/ titanium dioxide and Polymethylmetha acrylate/ titanium dioxide composites for weight ratio of 1.9/ 0.1 and 1.8/ 0.2 wt% for different thickness of the samples. The experimental results show that the thermal conductivity is increased with the increasing of thickness of layers and with the weight ratio of TiO2
The political system in Indonesia, since gaining independence from the Dutch colonialism on the seventeenth of August 1945, has gone through long stages. The Indonesian constitution stipulated that the country is based on a democracy. In 1956 the first free elections were held in Indonesia, and President Sukarno announced the adoption of the directed democratic system Then, during the era of President Suharto, the state entered a phase called democracy based on the Five Pancasila principles, which is a false democracy because it served the interests of Suharto, who in his long reign had political and economic corruption leading up to 1998, when the Indonesian people revolted, and the government of Soeharto was overthrown
... Show More
The primary purpose of the present research was to study the effect of polyvinyl chloride (PVC) powder content on ultrasonic wave velocity in PVC/Epoxy composites. The second part is concerned with the relations of dynamic elastic moduli with the ultrasonic wave velocities, to determine how ultrasonic waves can affect them.
Experimental data have been obtained using the sonic viewer (model -5217 A) device to generate two types of waves, longitudinal waves of frequency 63 kHz and transverse waves of frequency 33 kHz and to measure the transit time required for those waves to travel through individual sample.
The experimental results have shown that the propagation of the ultrasonic velocity increases directly with PVC content in the
Frictional heat is generated when the clutch starts to engag. As a result of this operation the surface temperature is increased rapidly due to the difference in speed between the driving and driven parts. The influence of the thickness of frictional facing on the distribution of the contact pressure of the multi-disc clutches has been investigated using a numerical approach (the finite element method). The analysis of contact problem has been carried out for a multiple disc dry clutch (piston, clutch discs, separators and pressure plate). The results present the distribution of the contact pressure on all tShe surfaces of friction discs that existed in the friction clutch system. Axisymmetric finite element models have been developed to ac
... Show More
(9)
(9)
(2)