Abstract: Objectives: To investigate the effect of temperature elevation on the bonding strength of resin cement to the zirconia ceramic using fractional CO2 laser. Background: Fractional CO2 laser is an effective surface treatment of zirconia ceramic, as it increases the bonding strength of zirconia to resin cement. Methods: Thirty sintered zirconia discs (10 mm diameter, 2 mm thickness) were prepared and divided to three groups (N=10) and five diffident pulse durations were used in each group (0.1, 0.5, 1, 5 and 10 ms). Group A was treated with 10 W power setting, group B with 20 W and group C with 30 W. During laser irradiation, temperature elevation measurement was recorded for each specimen. Luting cement was bonded to the treated zirconia surfaces and cured for 30 seconds. Shear bond strength was evaluated by a testing machine (universal) with bond failure mode determination. Results: The lowest temperature elevation measurement of the irradiated specimen which gave maximum shear bond strength was about 1.6±0.3 Ċ higher than ambient room temperature (27±0.2 ºC). Apparent micromechanical irregularities were seen in the treated samples and cracks formation with increased pulse duration and power setting were also observed. Conclusions: The temperature elevation is a vital factor in the surface roughness of zirconia ceramic with fractional CO2 laser irradiation and the lowest temperature elevation at best shear bond strength of zirconia ceramic to the resin cement is satisfied with the shorter pulse duration of 0.1 millisecond.
In the last decades, using mineral admixture in concrete became very necessary to improve concrete properties and reduce CO2 emissions associated with the cement production process. Subsequently, more sustainable concrete can be obtained. Ternary blended cement containing two different types of mineral admixture can achieve ambitious steps in this trend. In this research, the synergic effects of mineral admixtures in ternary blended cement and its effects on concrete fresh properties, strength, durability, and efficiency factors of mineral admixture in ternary blended cement, were reviewed. The main conclusion reached after reviewing many literature pieces is that the concrete with ternary blended cement
... Show MoreDental caries (tooth decay) is one of the most prevalent infectious disease and although of multifactorial origin, Streptococcus mutans is considered the principal pathogen in its development (i.e. bacterial processes damage hard tooth structure (enamel, dentine and cementum), producing dental cavities (holes in the teeth). The bactericidal properties of the Nd:YAG laser has been researched analyzing its use in caries prevention and bacterial reduction. One hundred twenty five samples were collected from carious teeth and isolated bacteria were diagnosed using microscopic examination, culture, biochemical tests, and Api 20 strep system. The results of this study showed that a noticeable decrease in the viability of Streptococcus mutans w
... Show MoreThis study aims to investigate the academic leaders’ perceptions towards the degree of availability of the dimensions of organizational immunity systems at the University of Tabuk, as well as to reveal the statistically significant differences between the average responses of the study sample members about the degree of availability of these dimensions at their university due to the variables of (gender, leadership position, and college specialization). To achieve the objectives of the study, a descriptive survey method was used. The study population consisted of (200) male and female leaders who were academic leaders at the University of Tabuk. A questionnaire was used as a tool for collecting data, which its validity and reliability
... Show MoreAutorías: Ghassan Adeeb Abdulhasan, Rasha Raed Hamid Hameed, Hussein Jabber Abood. Localización: Revista iberoamericana de psicología del ejercicio y el deporte. Nº. 6, 2022. Artículo de Revista en Dialnet.
The research was conducted between 2017 and 2019 at the College of Agricultural Engineering Sciences and Laboratory of Plant Tissue Culture for Postgraduate Studies at the University of Baghdad. One experiment used a totally random design. The experiment examined the effects of PEG (Polyethylene glycol) at concentrations of 0, 2, 4, 6, and 8% on the development of three sunflower types (Ishaqi-1, Aqmar, and AL-Haja) exposed to UV-C rays for 40 minutes as a result of the growing of the juvenile peduncle outside the live body. The aim of the study was to better comprehend the physiological and biochemical changes caused by water stress on the callus of several sunfl
The Organizational Transparency is regarded one of the effective means in the attempts of the restoration and working to prevent the corruption and reduce the negative managerial economic social and political effects.
Accordingly, this study aims at importance of performing an explorative analytical study in order to stand on the effect of the Organizational Transparency in the reduction of environment of Iraqi Organizations.
To achieve this study, three hypotheses were chosen; the first is the correlation relation and the second is the effect and the third is the differences, and statistical means represented by correlation coefficient "Spearman", "", "Mann- Whit
... Show MorePurpose: To use the balanced measurement approach as a strategic link for increasing the effectiveness of strategic planning in the direction of achieving satisfaction rates at Bisha University in Saudi Arabia
Design / methodology / approach –The questionnaire survey was used to collect the data of the study from the faculty members at University of Bisha.
Findings –Prove the assumption that the use of the balanced measurement approach - as a strategic planning tool - leads to maximize the satisfaction rates among faculty members at the University of Bisha.
Research limitations/implications- adopt effective strategic planning in order to achieve
... Show MoreA study of non-diatom algal species composition in twelve sites from Greater Zab River path within
Erbil Province, was carried out from April 2021 to January 2022 with monthly sample collection in twelve studied sites. Among them site 4,5,6,7 and 9 are the first for algal study in this area. The 112 different species of algae belong to 33 genera, 25 families, 13 orders and 4 divisions have been identified. The predominant genera included Spirogyra and Cosmarium 17, 8 taxa respectively. 13 taxa were new recorded to Iraqi
Kurdistan algal flora and 9 of them were new recorded to Iraqi algal flora: Botryosphaerella sudetica, Muriella magna, Gloeotaenium loitlesbergianum, Apiocystis brauniana, Anabaena oscillarioides, C. distentum
This study was conducted to investigate the effect of feeding diets containing different levels of parsley on the hematological traits of local Iraqi geese. A total of twenty-four local geese, one year old, were used in this experiment. The birds were allocated into four treatment groups, consisting of six geese each. Treatment groups were: control diet (C) (free from parsley); T1: control diet + 80 g/d parsley; T2: control diet + 160 g/d parsley; and T3: control diet + 240 g/d parsley. At the end of the experiment, blood samples were obtained from all geese from the brachial vein by venipuncture. Hematological traits included in this study were red blood cells count (RBC), hemoglobin concentration (Hb), packed cell volume (PCV), mean cell
... Show MoreTigris River is the lifeline that supplies a great part of Iraq with water from north to south. Throughout its entire length, the river is battered by various types of pollutants such as wastewater effluents from municipal, industrial, agricultural activities, and others. Hence, the water quality assessment of the Tigris River is crucial in ensuring that appropriate and adequate measures are taken to save the river from as much pollution as possible. In this study, six water treatment plants (WTPs) situated on the two-banks of the Tigris within Baghdad City were Al Karkh; Sharq Dijla; Al Wathba; Al Karama; Al Doura, and Al Wahda from northern Baghdad to its south, that selected to determine the removal efficiency of turbidity and
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