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.
A microbial desalination cell (MDC) is a new approach to bioelectrochemical systems. It provides a more sustainable way to electrical power production, saltwater desalination, and wastewater treatment at the same time. This study examined three operation modes of the MDC: chemical cathode, air cathode, and biocathode MDC, to give clear sight of this system's performance. The experimental work results for these three modes were recorded as power densities generation, saltwater desalination rates, and COD removal percentages. For the chemical cathode MDC, the power density was 96.8 mW/m2, the desalination rate was 84.08 ppm/hr, and the COD removal percentage was 95.94%. The air cathode MDC results were different
... Show MoreThis study examines the impact of adopting International Financial Reporting Standards (IFRS) on the value of economic units. Given the global push toward standardization of financial reporting to enhance financial statement transparency, comparability, and reliability, this research seeks to understand the implications of these standards for economic valuation within a region characterized by its unique economic and regulatory challenges. A questionnaire was distributed to 86 Iraqi academics specializing in economics, accounting, and finance to collect their views on the impact of adopting international financial reporting standards. Through careful statistical analysis, the study concluded that applying international financial reporting s
... Show MoreThe article deals with the role of metaphors in forming the plot of L. Ulitskaya’s family chronicle “Medea and Her Children”. The author of the article describes the results of the next stage of research related to the works of Lyudmila Evgenievna Ulitskaya, a representative of modern Russian prose. The analysis of tropes and figures in the works written at the turn of the XXth – XXIth centuries is of importance for the study of the modern state of Russian language as an independent system. “Medea and Her Children” is one of the works by L. Ulitskaya (written in 1996), which, like her other works, is characterized by a unique style of narration, rich in vocabulary, lexical, semantic and stylistic diversity of the author’s word
... Show MoreThe experiment was carried out in College of Agricultural Engineering Sciences, University of Baghdad during November 1, 2019 to June 1, 2020. The experiment was designed according to a randomized complete block design. Each block contained 18 experimental units that included the three study factors. The first factor interaction between two inoculum densities and application methods, three levels control, treatment of seeds inoculation with 5g plant and treatment of seedlings inoculation whith 30g plant . The second factor was three -1 -1concentrations of spraying of kinetin 0, 75 and 150 mg L , and third factor include two levels of organic manure) and addition of fertilizer 2% of -1 the weight of the soil (O2). The results showed a signif
... Show MoreCadmium sulfide (CdS) thin films with n-type semiconductor characteristics were prepared by flash evaporating method on glass substrates. Some films were annealed at 250 oC for 1hr in air. The thicknesses of the films was estimated to be 0.5µ by the spectrometer measurement. Structural, morphological, electrical, optical and photoconductivity properties of CdS films have been investigated by X-ray diffraction, AFM, the Hall effect, optical transmittance spectra and photoconductivity analysis, respectively. X-ray diffraction (XRD) pattern shows that CdS films are in the stable hexagonal crystalline structure. Using Debye Scherrerś formula, the average grain size for the samples was found to be 26 nm. The transmittance of the
... Show MoreThis century is witnessing changes in various fields,which have become a challenge to the enterprises in the contemporary business environment, the most important of which is the importance of measurement and disclosure of the role of knowledge capital in the transition to the knowledge economy, which is no longer the land and labor and physical capital resources the basic. Knowledge-based capital has emerged that provides the enterprise with an area of excellence and enhances its position to achieve competitive advantage. The research tackled the concept, objectives, components and importance of knowledge capital, which is fundamental in knowledge management, creating value added and enhancing competitiveness, as well as an
... Show MoreThis paper offers a postcolonial analysis of Sudanese author Tayeb Salih's novel Season of Migration to the North (1966), emphasizing the interplay between indigenous and colonial narratives. The analysis centers on the protagonist, Mustafa Sa'eed, who embodies its essence. The character of Mustafa Saeed represents the intricate interplay between colonial and indigenous elements. This research employs Edward Said's postcolonial concept, Contrapuntal Reading (1993), which underscores the interconnection of the histories of colonizers and the colonized through the portrayal of Mustafa Saeed's character, focusing on the mechanisms of colonial power, such as cultural hegemony, identity manipulation, and the resistance of the colonized.
... Show MoreThe construction sector consumes large amounts of energy during the lifetime of a building. This consumption starts with manufacturing and transferring building materials to the sites and demolishing this building after a long time of occupying it. The topic of energy conservation and finding the solution inside the building spaces become an important and urgent necessity. It is known that the roof is exposed to a high amount of thermal loads compared to other elements in a building envelope, so this needs some solutions and treatments to control the flow of the heat through them. These solutions and treatments may be achieved by using nanomaterials. Recently, nanomaterials have high properties, so that this made them go
... Show MoreIs the efficiency of physical and your endurance is of great importance for some activities and field, as it whenever the situation has improved student career was able to perform physical exertion more with energy saving efforts, so the identification of physical aptitude and endurance private students, was based on that there are positively correlated the carrying of training and pregnancy fact on the shoulders of the student. In other words, physical aptitude and endurance in your control level that can be shown by the student during the performance of training and competitions. Therefore, lies the importance of research to test physical aptitude and endurance your help to reveal the career of the body in the light of their relationship
... Show MoreClimate change in recent years has greatly affected the distribution of ground covers. Monitoring these changes has become very easy due to the development of remote sensitivity science and the use of satellites to monitor these changes. The aim of this research is to monitor changes in the spectral reflectivity of the Baghdad governorate center for the month (March, June, September, December) of the year 2021 using remote sensing and satellite images Sentinel 2 and knowing the climate imact on them. Fifty-one samples were selected for four types of ground cover (agricultural land, water, buildings and open space) and their spectral reflectivity was calculated using satellite images.