Hydrophobic silica aerogels were successfully preparation by an ambient pressure drying method from sodium silicate (Na2SiO3) with different pH values (5, 6, 7, 8, 9 and 10). In this study, acidic HCl (1M), a basic NH4OH (1M) were selected as a catalyst to perform the surface modification in a TMCS (trimethylchlorosilane) solution. The surface chemical modification of the aerogels was assured by the Fourier transform infrared (FTIR) spectroscopic studies. Other physical properties, such as pore volume and pore size and specific surface area were determined by Brunauer-Emmett- Teller (BET) method. The effect of pH values on the bulk density of aerogel. The sol–gel parameter pH value in the sol, have marked effects on the physical properties of the silica aerogels produced by this technique. The density and the hydrophobic tendency of the aerogels were significantly influenced.
Background: to evaluate the effect of different dentifrices on the surface roughness of two composite resins (nanofilled-based and nanoceramic – based composite resins). Materials and methods: Forty specimens (diameter 12 mm and height of 2mm) prepared from different composite resin materials: Z350 (nanofilled composite, and Ceram-X (nanoceramic) .they were subjected to brushing simulation equivalent to the period of 1 year. The groups assessed were a control group brushed with distilled water (G1), Opalescence whitening toothpasteR (G2), Colgate sensitive pro-relief (G3) and Biomed Charcoal Toothpaste (G4). The initial and final roughness of each group was tested by surface roughness tester. The results were statistically analyzed using
... Show MoreThis research studied the relationship of patterns of investigator personality with the big five dimensions (Extraversion, stability, interoperability, openness, and personal benevolent), in facing the job stress with its resources(characteristics of the role, quality of work, organizational structure, work environment, organizational policies, social relations, and organizational processes) which the investigators exposed to it at the General Inspectors Offices.
The researcher derived the idea of research from the importance of the work of these offices in a confrontation of various cases of financial and administrative corruption in Iraq at the present time, since itis one of the most important in
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To evaluate the effectiveness of Phenolic Compound of Salvia Frigida on induced atopic dermatitis (AD) of mice. Forty mice were included in the study, divided in to four groups (10 mice/group): apparently healthy, induced AD without treatment, induced AD treated with tacrolimus 0.1% ointment, and induced AD treated with Phenolic Compound of Salvia Frigida cream 5%. Examination of histopathology was done and skin homogenates levels also measured. Levels of WBC, Eosinophil, skin tissue homogenate of IL-13 and IL-4, serum IgE, and histopathological scores were significantly increased among induced non treated AD group in comparison with control group. Comparisons of non-treated induced AD
... Show MoreThe international business environment faces many challenges, including the intensity of competition, the speed of expansion, and control of the market. This leads to its shadow on the local business environment, which prompted many economic units to adopt modern strategies, including mergers and acquisitions, for expansion and prosperity. The research was conducted to verify the role of internal audit in the governance of strategy operations (Mergers and acquisitions) and its reflection on management decisions and making them efficient and effective. Internal auditing is the independent variable related to the other variable, the governance of strategic operations and its impact on management decisions for strategic operations as a depende
... Show MoreThis research is addressing the effect of different ferrocene concentration (0.00, 2.15x10-3, 4.30x10-3, 8.60x10-3, and 12.9x10-3) on the bulk free radical polymerization of methyl methacrylate monomer in benzene using benzoyl peroxide as initiator. The polymerization was conducted at 60º C under free oxygen atmosphere. The resulting polymers were characterized by FTIR. The results were compared with the presence and absence of ferrocene at 10% conversion. The %conversion was 3.04% with no ferrocene present in the polymerization medium and its increase to 9.06 with a first lowest ferrocene concentration added, i.e. 2.15 x10-3mol/l. This was positively reflected on the poly(methyl methacrylate) molecular weight measured by viscosity techniq
... Show MoreThe principle of citizenship has international dimensions that affect the application of the principle, such as the structure of the international system, and the control of the concepts of globalization, international organizations which played an important role in the consolidation of this principle.
The problem of the study revolves around the effects of international variables on the principle of citizenship in Kuwait during the period 1991-2018.
The study used several indicators, such as: the rule of law, achieving the principle of separation of powers, the right to form parties, the application of the law of nationality, and racial discrimination, women's rights, and freedom of expression.
ABSTRACT The isolation and characterization of (27) isolate of extreme halophilic bacteria was performed ninteen isolate belonged to the genus Halobacterium which included Hb.halobium. Hb. salinarium, Hb. volcanii. Growth curve and generation time in logarthmic phase was measured and found to be (12.8hr±0.32), (11.2hr±0.2), (9.8hr±0.87), respectivaly. Effect of various concentrations of NaCl, KCI, NH4Cl and MgSO4.7H2O was studied, NaCl was essential for the rod shape rapid growth Rat and pigmentation. Less than 1% concentration caused lysis of bacteria. Yeast extract was the best carbone source as compared with glucose and casamino acid.
The press release plays an important role in understanding and recognizing the policy of governments by the public in managing the state, especially in times of crises, as it helps to clarify the position of the government and its decisions.In addition, it is considered as one of the most important tools of communication between the government and its public at the present time.
In light of the technical developments and adopting modern mechanisms in transferring of what is issued by the government, the press release has been edited and published electronically; and helps in the success of this transfer speed and knowledge of the reactions of the masses towards the implications,In a crisis like the Basrah crisis in particular, the Ira
In this paper, numerical and experimental studies on the elastic behavior of glass fiber reinforced polymer (GFRP) with stiffeners in the GFRP section's web (to prevent local buckling) are presented. The GFRP profiles were connected to the concrete deck slab by shear connectors. Two full-scale simply supported composite beams (with and without stiffeners) were tested under impact load (three-point load) to assess its structural response. The results proved that the maximum impact force, maximum deflection, damping time, and damping ratio of the composite beam were affected by the GFRP stiffeners. The experimental results indicated that the damping ratio and deflection were diminished compare
... Show MoreThis study presents an investigation about the effect of fire flame on the punching shear strength of hybrid fiber reinforced concrete flat plates. The main considered parameters are the fiber type (steel or glass) and the burning steady-state temperatures (500 and 600°C). A total of 9 half-scale flat plate specimens of dimensions 1500mm×1500mm×100mm and 1.5% fiber volume fraction were cast and divided into 3 groups. Each group consisted of 3 specimens that were identical to those in the other groups. The specimens of the second and the third groups were subjected to fire flame influence for 1 hour and steady-state temperature of 500 and 600°C respectively. Regarding the cooling process, water sprinkling was applied directly aft
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