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Standardized Assessment of Compressive Behavior in Rigid Polyurethane Foams: Influence of Density, Crosslinking, and Aging
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Rigid polyurethane foams (RPUFs) are essential materials in structural applications due to their thermal insulation, lightweight properties, and mechanical strength. However, evaluating and comparing their compressive performance is complicated by differences in formulation parameters such as density, aging, and crosslink density. This study proposes a standardized normalization approach to evaluate compressive properties across diverse RPUF formulations by adjusting all data to a common reference density. Samples were subjected to controlled aging conditions and analyzed using dynamic mechanical thermal analysis (DMTA) to investigate the relationship between crosslinking behavior and mechanical performance. The results demonstrate that aging, formulation composition, and isocyanate index significantly influence the foam’s compressive strength and modulus, as well as its thermal transitions. The proposed method enables a more reliable and efficient comparison of RPUF performance, offering practical implications for optimizing formulation design in construction, automotive, and aerospace applications where mechanical integrity and durability are critical.

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Publication Date
Mon Feb 18 2019
Journal Name
Iraqi Journal Of Physics
Drought assessment in Iraq using analysis of Standardized precipitation index (SPI)
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The Present study investigated the drought in Iraq, by using the rainfall data which obtained from 39 meteorological stations for the past 30 years (1980-2010). The drought coefficient calculated on basis of the standard precipitation index (SPI) and then characteristics of drought magnitude, duration and intensity were analyzed. The correlation and regression between magnitude and duration of drought were obtained according the (SPI) index. The result shows that drought magnitude values were greater in the northeast region of Iraq. 

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Publication Date
Sun Jul 09 2023
Journal Name
Journal Of Engineering
Influence of Aging Time on Asphalt Pavement Performance
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Aging of asphalt pavements typically occurs through oxidation of the asphalt and evaporation of the lighter maltenes from the binder. The main objective of this study is to evaluate influence of aging on performance of asphalt paving materials.nAsphalt concrete mixtures, were prepared, and subjected to short term aging (STA) procedure which involved heating the loose mixtures in an oven for two aging period of (4 and 8) hours at a temperature of 135 o C. Then it was subject to Long term aging (LTA) procedure using (2 and 5) days aging periods at 85 o C for Marshall compacted specimens. The effect of aging periods on properties of asphalt concrete at optimum asphalt content such as Marshall Properties, indirect tensile strength at 25 o C,

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Publication Date
Wed Nov 07 2018
Journal Name
Iraqi National Journal Of Nursing Specialties
Assessment of Nurses' Practices Toward Infection Control Standardized Precautions in Azady Teaching Hospital in the City of Kirkuk
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Objective: The aim of the present study is to assess the practices of nurses towards standard precautions at Azady
Teaching Hospital in the City of Kirkuk.
Methodology: A descriptive study, which uses the assessment approach and it was conducted on nurses from January
18th, 2009 to September 30th, 2009, using non-probability sampling a purposive sample of (37) subject (male and
female nurses) who worked at surgical wards in Azady Teaching Hospital in Kirkuk city was selected. Two study
instruments were utilized for proper data collection [questionnaire and observational checklist]; a questionnaire was
developed for the purpose of the study. It was comprised of two parts which included the nurses' demographic
characte

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Publication Date
Sat Jan 14 2017
Journal Name
Chemical And Biomolecular Engineering
Influence of Nano Additives on Unconfined Compressive Strength of Asphaltic Soil
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Collapsible behaviour of soil is considered as one of the major problems in the stability of roadway embankment, the lack of cohesion between soil particles and its sensitivity to the change of moisture content are reasons for such problem. Creation of such cohesion may be achieved by implementation of liquid asphalt and introduction of Nano additives. In this work, silica fumes, fly ash and lime have been implemented with the aid of asphalt emulsion to improve the unconfined compressive strength of the collapsible soil. Specimens of 38 mm in diameter and 76 mm height have been prepared with various percentages of each type of Nano additive and fluid content. Specimens were subjected to unconfined compressive strength determination at dry a

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Publication Date
Tue Jul 28 2026
Journal Name
Journal Of Baghdad College Of Dentistry
Assessment of microvessels density and inflammatory status in oral lichen planus
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Background: Oral lichen planus (OLP) is a chronic inflammatory disease with an autoimmune inflammatory pathogenesis. The purpose of this study was to evaluate the role of angiogenesis in the pathogenesis of OLP, using CD34 stain to highlight the blood vessels for measuring the microvessel density (MVD) as well as to evaluate the relation of this marker with the degree of inflammation Materials and Methods: Immunohistochemical (IHC) staining technique was used to evaluate angiogenesis using CD34 in 46 paraffin blocks 10 of them obtained from normal mucosa and 36 from cases diagnosed as lichen planus , 20 of them diagnosed as Reticular type while 16 as erosive type. Severity of inflammation was divided into mild, moderate and severe accordi

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Publication Date
Mon Mar 01 2021
Journal Name
Al-khwarizmi Engineering Journal
Influence of Aging Heat Treatment on Pitting Corrosion Resistance of Martensitic Stainless Steel
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In this research is to study the influence of the aging heat treatment on the pitting corrosion resistance of martensitic stainless steel (MSS), where a number of specimens from martensitic stainless steel were subjected to solution treatment at 1100 oC for one hour followed by water quenching then aging in the temperatures range (500-750) oC for different holding times (1,5,10,15&20) hr. Accelerated chemical corrosion test and immersion chemical corrosion test were performed on samples after heat treatment. The results of the research showed that the pitting corrosion resistance is significantly affected by the aging temperature. Where found that the aging samples at a temperature of 500 °C have the highest ra

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Publication Date
Tue Jan 01 2008
Journal Name
J Bagh College Of Dentistry
Assessment of consistency and compressive strength of glass ionomer reinforced by different amount of hydroxyapatite
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Background: Glass ionomers have good biocompatibility and the ability to adhere to both enamel and dentin. However, they have certain demerits, mainly low tensile and compressive strengths. Therefore, this study was done to assess consistency and compressive strength of glass ionomer reinforced by different amount of hydroxyapatite. Materials and Methods: In this study hydroxyapatite materials were added to glass ionomer cement at different ratios, 10%, 15%, 20%, 25% and 30% (by weight). The standard consistency test described in America dental association (ADA) specification No. 8 was used, so that all new base materials could be conveniently mixed and the results would be of comparable value and the compressive strength test described by

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Publication Date
Mon Jun 05 2023
Journal Name
Journal Of Engineering
Compressive Behavior of Fiber Reinforced Concrete Columns Rehabilitated with CFRP Warps
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Over the last few years, there has been a worldwide increase in the use of composite materials for rehabilitation of deficient reinforced concrete structures. One important application of this technology is the use of Carbon Fiber Reinforced Polymer (CFRP) jacket to provide external confinement of reinforced concrete columns. Square concrete column specimens 100×100×1000 mm with concrete
compressive strength of about 30 and 50 MPa, steel fiber volume fraction 0%, 0.5%, 0.75%, and percentage of longitudinal reinforcement 2.01%, 3.14% and 4.52% were tested until failure in previous research. In this research seven tested columns were repaired and rehabilitated using one layer of CFRP flexible wraps and tested to determine their ultim

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Publication Date
Wed Dec 13 2017
Journal Name
Al-khwarizmi Engineering Journal
Enhancing the Compressive Strength and Density of Cement Mortar by the Addition of Different Alignments of Glass Fibers and Styrene Butadiene Rubber
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Abstract

In the field of construction materials the glass reinforced mortar and Styrene Butadiene mortar are modern composite materials. This study experimentally investigated the effect of addition of randomly dispersed glass fibers and layered glass fibers on density and compressive strength of mortar with and without the presence of Styrene Butadiene Rubber (SBR). Mixtures of 1:2 cement/sand ratio and 0.5 water/cement ratio were prepared for making mortar. The glass fibers were added by two manners, layers and random with weight percentages of (0.54, 0.76, 1.1 and 1.42). The specimens were divided into two series: glass-fiber reinforced mortar without SBR and glass-fiber reinforced mortar with 7% SBR of mixture water. All s

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Publication Date
Sat Jan 31 2015
Journal Name
International Journal Of Research In Applied, Natural And Social Sciences
The Influence of Premenopausal Simple Hysterectomy on Bone Mass Density
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