Instruments for the measurements of radon, thoron and its decay
products in air are based mostly on the detection of alpha particles.
The health hazards of radon on general public are well known. In
order to understand the level and distribution of 222Rn concentrations
indoor in Al-Fallujah City; new technique was used, this technique
was three radon–thoron mixed field dosimeters is made up of a twin
chamber cylindrical system and three LR-115 type II detectors were
employed. The aim of this work was to measurement radon gas using
SSNTD technique door in in Al-Fallujah City, and estimation of
excess in cancer due to increment in radon gas. Results for samples
which are collected from January to April 2013 show that the 222Rn
concentration varies from 52.33 to 108.70 Bq.m-3 with an average of
84.64 Bq.m-3, according to EPA and ICRP, the average indoor radon
level should be 148 Bq/m3 and 300 Bq/m3, respectively, whereas
approximately 15 Bq/m3 (ranging from 1 Bq/m3 to 100 Bq/m3 of
radon concentration is normally found in outside air. Also the values
of annual effective dose and excess lung cancer per million people
per year (ELC) have also been calculated and found to vary from
0.941 to 2.350 mSv.y-1 with an overall average of 1.581 mSv.y-1 and,
565 to 1410 with an overall average 948, respectively.
In this work, varying compositions of SiO2 micro filler were added
with the Polyvinyl Chloride (PVC) and samples have been prepared
using film casting technique. The results have been analyzed and
compared for PVC samples with (1 wt%, 3 wt%, 5 wt% and 10 wt%)
SiO2 micro filler. Mechanical characteristics such as tensile strength,
elongation at break and Young`s modulus were measured for all the
samples, where the tensile strength was increased from 8.39 Mpa for
purified PVC to 16 Mpa for 3% SiO2/PVC composite. Also, thermal
conductivity measurement values illustrated that composite materials
have a good thermal insulation at 10 wt. %, thermal conductivity was
decreased from 0.1684 W/m.
Background: Poly (methylmethacrylate) is the most widely used material in denture fabrication. The characteristics of acrylic resin which support microorganism development can threaten the oral health of denture users. This study was assigned to prepareand incorporate Ag-Zn zeolite powder into heat cured denture base material as antimicrobial material and to investigate its effect on some properties of heat cured acrylic denture base materials. Materials and methods: Sliver –zinc zeolite was prepared by ion exchange method and characterized then incorporated into poly (methylmethacrylate) powder in0.5% by weight. Specimens were constructed and divided into 6 groups according to the using tests; each group was subdivided into 2 groups
... Show MoreBackground: The geriatric patients wearing removable partial dentures are increasing in proportion. At the same time, the root caries prevalence accompanied by gingival recession is increasing. A variety of vehicles can deliver fluoride into the oral cavity, including fluoride mouth-rinse, fluoride dentifrice, topical fluoride, and fluoride-releasing restorative materials, all of which effectively prevent root caries and suppress recurrent caries. This study aimed to evaluate the effect of sodium fluoride addition on some mechanical properties of heat cure acrylic denture base material. Material and method: A total of 90 samples were prepared in this study, then divided into three main groups according to the type of test used (hardness, te
... Show MoreIn this research, some probability characteristics functions (probability density, characteristic, correlation and spectral density) are derived depending upon the smallest variance of the exact solution of supposing stochastic non-linear Fredholm integral equation of the second kind found by Adomian decomposition method (A.D.M)
Background Microorganisms and fungal growth especially Candida albicans, on soft denture lining material are the most common problem which can lead to chronic mucosal inflammation. The aim of this study was to evaluate the effect of zirconium nanoparticles into acrylic-based heat cured soft denture lining material against Candida albicans, and the amount of zirconium ion release of soft liner/ZrNPs composite. Furthermore, evaluate shear bond strength after ZrNPs addition to soft liner. Materials and methods: Zirconium nanoparticles were added into acrylic-based soft denture liner in various percentages (1%, and 1.5% by weight). Two hundred and fifty specimens were arranged and isolated into four groups as per the test to be done The antifu
... Show MoreThe accumulation of construction and demolition waste is one of the major problems in modern construction. Hence, this research investigates the use of waste brick in concrete. Seven different concrete mixes were investigated in this study: a control concrete mix, three mixes with volumetric replacement (10, 20, and 30)% of natural aggregate with brick aggregate, and two mixes with the addition of nano brick powder at a percentage level of 5– 10% by weight of cementitious materials. And the last one was mixed with 10% nano brick and 10% coarse brick aggregate. The experimental results for the additive of nano brick powder showed an enhancement in mechanical properties (compressive,
the most important purposes and uses of the test results in the educational sector. This is because the quality of tests is related to their ability to predict the learner's behavior in the future, and the accuracy of the educational and administrative decisions that are taken in light of their results. The study aimed accordingly to reveal the predictive ability of the university Grade Point Average (GPA) in the Score of the specialized test for the position of teacher in the Ministry of Education in the Sultanate of Oman. It further aimed to investigate the differences in the predictive ability according to the specialization and academic year using the descriptive approach. The sample of the study consisted of (349) s/he students enro
... Show MoreOur aim in this paper is to study the relationships between min-cs modules and some other known generalizations of cs-modules such as ECS-modules, P-extending modules and n-extending modules. Also we introduce and study the relationships between direct sum of mic-cs modules and mc-injectivity.
Bacterial toxins are considered to be virulence factors due to the fact that they interfere with the normal processes of the host cell in which they are found. The interplay between the infectious processes of bacteria and the immune system is what causes this impact. In this discussion, we are going to focus on bacterial toxins that act in the extracellular environment, especially on those that impair the activity of macrophages and neutrophils. These toxins are of particular interest since they may be found in a wide variety of bacteria. We will be concentrating our efforts, in particular, on the toxins that are generated by Gram-positive and Gram-negative bacteria. These toxins are able to interact with and have an effect on the many dif
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