Background: This in vitro study was carried out to investigate the effect of post space regions (coronal, middle and apical), the effect of post types ( Manually Milled Zirconia post, Prefabricated Fiber post, prefabricated Zirconia post) and the type of cement used (GIC, self-adhesive resin cement) on the bond strength between the posts and root dentin by using push-out test. Material and methods: Forty eight mandibular premolars extracted for orthodontic reasons (single rooted) were instrumented with ProTaper system (hand use) and obturated with gutta percha for ProTaper using AH26® root canal sealer following the manufacturer instructions. After 24 hours, post space was prepared using Zirix and Glassix drills no.3 creating 8 mm depth post space. The prepared samples were randomly divided into three main groups (16 samples each) according to the type of post used (Group A. Manually Milled Zirconia post, Group B. Prefabricated Fiber post and Group C. Prefabricated Zirconia post) .each group was subdivided into two subgroups (each subgroup contains 8 samples) according to the type of cement used (subgroup A1.Manually Milled Zirconia post cemented with GIC, subgroup A2.Manually Milled Zirconia post cemented with Speed cem),( subgroup B1.Prefabricated Fiber post cemented with GIC, Group B2. Prefabricated Fiber post cemented with Speed cem) and (subgroup C1.Prefabricated Zirconia post cemented with GIC, subgroup C2. Prefabricated Zirconia post cemented with Speed cem), after cementation and incubation for 24hrs, at 37°c and 100% humidity. Each root was sectioned horizontally into 3 slices (2 mm in thickness) representing the coronal, middle and apical regions of the post space. Push out bond strength test was performed and measured using a universal testing machine (Tinius-Olsen) at across head speed of 0.5 mm/min. Results: The results showed that regarding the root region, the bond strength values increased significantly from apical to coronal region for all types of posts in both tested cements. For the effect of post type, the manually Milled Zirconia post cemented with the self-cured resin cement (Speed cem) showed higher bond strength values. For type of cement, the self-adhesive resin cement (Speed cem) showed higher bond strength values. Conclusions: the retention of post restoration was affected by root region, type of post and type of cement used.
The purpose of this paper is to study the instability of the zero solution of some type of nonlinear delay differential equations of fifth order with delay by using the Lyapunov-Krasovskii functional approach, we obtain some conditions of instability of solution of such equation.
Metaphor is one of the most important linguistic phenomena of the artistic text, as it is the expression of the author’s emotions and evaluations, the result of a deep inner transformation of the semantic words and visual means of reflecting the national culture of each people. This paper examines the concept of linguistic metaphors and analyzes its types in the Russian and Arabic linguistics, provides a comparative analysis of metaphors in Russian and Arabic — all this allows to conclude that metaphorization is characteris- tic of different parts of speech. In the Russian language stylistic differentiation of the metaphors expressed more than in Arabic, so translation of many “sty- listic” metaphors from Russian into Arabic due to
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The aim of this research is to study the effect of welded joint design (Butt joint and lap joint) on thejoint strength during tension and fatigue loading with different current of welding (40,50,60,70,80) ^per, and different type of wire welding. The result of this research is showed that the effect of fatigue loading on the type of joint is more than the effect of tension loading on it. And the butt joint welding is better than the lap joint welding during the fatigue loaded.The experimental results of the effect of W'elding current showed that more increasing and more decreasing the value of the heat input, during the welding was found to produce mechanical brittleness on the buttjoint welding during the static and dynamic loading. Also i
... Show MoreIn this paper, image compression technique is presented based on the Zonal transform method. The DCT, Walsh, and Hadamard transform techniques are also implements. These different transforms are applied on SAR images using Different block size. The effects of implementing these different transforms are investigated. The main shortcoming associated with this radar imagery system is the presence of the speckle noise, which affected the compression results.
This research foxed on the effect of fire flame of different burning temperatures (300, 400 and 500)oC on the compressive strength of reactive powder concrete (RPC).The steady state duration of the burning test was (60)min. Local consuming material were used to mixed a RPC of compressive strength around (100) MPa. The tested specimens were reinforced by (3.0) cm hooked end steel fiber of (1100) MPa yield strength. Three steel fiber volume fraction were adopted in this study (0, 1.0and 1.5)% and two cooling process were included, gradual and sudden. It was concluding that increasing burning temperature decreases the residual compressive strength for RPC specimens of(0%) steel fiber volume fraction by (12.16, 19.46&24.49) and (18.20, 27.77 &3
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Background: The individual differences in emotional and behavioral style can be examined through personality instruments. These differences may explain the health status of the individuals. The purpose of the present study was to assess the influence of Personality Types on gingival and periodontal health status among teachers in Baghdad city in relation to selected salivary hormone (Dehydroepiandrosterone). Materials and methods: Females teachers 534 of randomly selected schools were subjected to personality questionnaire using The Riso-Hudson Enneagram Type Indicator. Teachers were examined to estimate the periodontal status according to the Community Periodontal Index (CPI). A group of teachers were selected for salivary analysis of Dehy
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Anew Solar concentrator have been designed in this paper, this concentrators Were based on the total internal reflection in a prism, the prism angles has been calculated by depending on the solar incident ray angle in baghdad for a year. The optical design consist ofa triangular presume, Where the solar cells on one side of the prism Wh?le the prism head towered the south. The results show that there is an increasing in the solar ray concentrators and the cell area is reduced.
The aim of this research is to know danger of radioactive isotopes
that are found in samples of drugs traded in Iraqi markets. The
samples are Iraqi Amoxicillin, English Amoxicillin, UAE
Amoxicillin, Indian Amoxicillin, Iraqi Paracetamol, English
Paracetamol, UAE Paracetamol and Indian Paracetamol. By high
purity germanium the activity of the following isotopes 40K, 214Pb,
228Ac and 137Cs is measured and the specific activity was used to
calculate the annual effective dose. Then the calculated annual
effective dose values are compared with the allowable annual
effective dose values of each part of digestive channel. This research
concluded that the measured annual effective dose values are not
dangerous.<
Abstract
In this work, diabetic glucose concentration level control under disturbing meal has been controlled using two set of advanced controllers. The first set is sliding mode controllers (classical and integral) and the second set is represented by optimal LQR controllers (classical and Min-, ax). Due to their characteristic features of disturbance rejection, both integral sliding mode controller and LQR Minmax controller are dedicated here for comparison. The Bergman minimal mathematical model was used to represent the dynamic behavior of a diabetic patient’s blood glucose concentration to the insulin injection. Simulations based on Matlab/Simulink, were performed to verify the performance of each controll
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