Gamma - irradiation effect on polymethylmethacrylate (PMMA) samples has been studied using Positron Annihilation Lifetime (PAL) method. The orthopositronium (o-Ps) lifetime τ₃, hence the o-ps parameters, the volume hole size (V_h) and the free volume fraction (Ꞙ_h) in the irradiated samples were measured as a function of gamma-irradiation dose up to 28.05 kGy. It has been shown that τ ₃, V_h, and Ꞙ_h, are increasing in general with increasing gamma-dose, to reach a maximum percentage increment of 22.42% in τ₃, 60% in V_h and 29.5% in Ꞙ_h, at. 2.55 kGy, whereas τ₂ reaches maximum increment of 119. 7% at 7.65 kGy. The results s

The problem of steady, laminar, natural convective flow in an square enclosure with and without partitions is considered for Rayleigh number (103-106) and Prandtl number (0.7). Vertical walls were maintained isothermal at different temperatures while horizontal walls and the partitions were insulated. The length of partition was taken constant. The number of partitions were placed on horizontal surface in staggered arrangement from (1– 3) and ratio of partition thickness (H/L= 0.033, 0.083, 0.124). The problem is formulated in terms of the vorticity-stream function procedure. A numerical solution based on a program in Fortran 90 with the finite difference method is obtained. Representative results illustrating the effects of the thickn

When a vehicle is left parked in the sun for an extended period, the gathered heat causes damage to several interiors within the cabin and causes discomfort for people and animals left inside the car. In the present work, the effect of the orientation of a parked white minibus on temperature distribution and cooling load calculation is studied experimentally in an open environment. Two different cases were studied facing south and facing east. For several hours, the temperature inside the car cabin had been monitored and measured at five separate locations. The cooling load calculations are carried out based on the experimental measurements. The results show that the overheating of parked cars always happens as a result

In the present work, pattern recognition is carried out by the contrast and relative variance of clouds. The K-mean clustering process is then applied to classify the cloud type; also, texture analysis being adopted to extract the textural features and using them in cloud classification process. The test image used in the classification process is the Meteosat-7 image for the D3 region.The K-mean method is adopted as an unsupervised classification. This method depends on the initial chosen seeds of cluster. Since, the initial seeds are chosen randomly, the user supply a set of means, or cluster centers in the n-dimensional space.The K-mean cluster has been applied on two bands (IR2 band) and (water vapour band).The textural analysis is used

The research aims to measure the impact of envy on job stress because the topic of envy represents a negative emotion that exists at all organizational levels, which may cause stress in the work environment.

The Research problem is represented by the lack of perception of most of the faculty staff on the negative effects of envy on their well-being in the Technical College of Management - Baghdad, and what is the impact level of envy on their job stress.

To achieve this, the scale of envy was based on two dimensions (being envied, Envying others), While the job stress scale was based on seven dimensions (workload, conflict role, Family factors, work environment, work relationships

This article dealt with identifying the importance of heat stress in poultry flocks and the damages resulting from the production of eggs and meat and the spread of pathogens, in addition to that ways to mitigate the harmful effects of heat stress, including physiological, nutritional, engineering and genetics, in order to ensure preservation of the product and reduce damages

Researching the effects of the research and technological development contract, determining its extent and demarcating the boundaries of the obligations imposed in it, is the cornerstone of economic growth and development, because defining these obligations removes the ambiguity and conflict between interests, by stating the rights owed to each party and even trying to reconcile them, or impose protection by specifying guarantees that are compatible with the essence of the R&D contract, For the purpose of studying the subject thoroughly, we will divide this research into two sections. The first is devoted to identifying the parties to the research and technological development contract. As for the other topic, we will explain the obligation

Background: Alum has been used as a treatment medication in cases of oral and gingival ulcers, and also as antiseptic mouthwash. This study aimed to examine the effects of different concentrations of Alum on inhibition zone, viability counts and adherence ability of Mutans streptococci compared with deionized water and chlorhexidine gluconate in vitro. Materials and methods: The study dealt with an in vitro study to establish a concentration of Alum mouthrinse that would have the minimum inhibitory concentration and minimum bacteriocidal concentration. The second part evaluated the anti-adherence ability of the experimental agents. Results: This study found that the antibacterial effect of Alum increases with its concentration from 50 to 1