Preferred Language
Articles
/
F3jzp58BuRolNscL8uds
Standardized Assessment of Compressive Behavior in Rigid Polyurethane Foams: Influence of Density, Crosslinking, and Aging
...Show More Authors

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.

Scopus Crossref
View Publication Preview PDF
Quick Preview PDF
Publication Date
Thu Jul 04 2019
Journal Name
International Journal Of Automotive And Mechanical Engineering
Nonlinear Buckling Analysis of Steel Cylindrical Shell with Elliptical Cut-out Subjected to Longitudinal Compressive Load
...Show More Authors

The current paper investigates the effect of cut-out design parameters on load-bearing capacity and buckling behaviour of steel cylindrical shell using a nonlinear finite element analysis in modelling cylinder buckling under longitudinal compressive load. The effect of four geometry design parameters: shell diameter to thickness ratio, cut-out location, orientation, and size were investigated in this study. To enhance the prediction of buckling behaviour, both geometrical and material nonlinearities were considered. An ANSYS APDL code was written and tested by verifying its validity through comparison with former buckling study. The results showed that changing the cut-out location from mid-height of the cylindrical shell towards a

... Show More
View Publication
Scopus (3)
Crossref (2)
Scopus Crossref
Publication Date
Wed Nov 30 2022
Journal Name
Iraqi Geological Journal
A Predictive Model for Estimating Unconfined Compressive Strength from Petrophysical Properties in the Buzurgan Oilfield, Khasib Formation, Using Log Data
...Show More Authors

Unconfined compressive strength (UCS) of rock is the most critical geomechanical property widely used as input parameters for designing fractures, analyzing wellbore stability, drilling programming and carrying out various petroleum engineering projects. The USC regulates rock deformation by measuring its strength and load-bearing capacity. The determination of UCS in the laboratory is a time-consuming and costly process. The current study aims to develop empirical equations to predict UCS using regression analysis by JMP software for the Khasib Formation in the Buzurgan oil fields, in southeastern Iraq using well-log data. The proposed equation accuracy was tested using the coefficient of determination (R²), the average absolute

... Show More
View Publication
Crossref
Publication Date
Sun Dec 07 2014
Journal Name
Baghdad Science Journal
Calculation of Radial Density Distribution Function for main orbital of Carbon atom and Carbon like ions
...Show More Authors

Radial density distribution function of one particle D(r1) was calculated for main orbital of carbon atom and carbon like ions (N+ and B- ) by using the Partitioning technique .The results presented for K and L shells for the Carbon atom and negative ion of Boron and positive ion for nitrogen ion . We observed that as atomic number increases the probability of existence of electrons near the nucleus increases and the maximum of the location r1 decreases. In this research the Hartree-fock wavefunctions have been computed using Mathcad computer software .

View Publication Preview PDF
Crossref
Publication Date
Tue Oct 02 2018
Journal Name
Iraqi Journal Of Physics
Effect of gas flow rate on plasma temperature and electron density of atmospheric argon plasma jet
...Show More Authors

In this study, method for experimentally determining the electron density (ne) and the electron temperature (Te) in the atmospheric Argon plasma jet is used; it is based on optical emission spectroscopy (OES). Boltzmann plot method used to calculate these parameters measured for different values of gas flow rate. The results show that the electron temperature decreasing with the increase of gas flow rate also indicates an increasing in the electron density of plasma jet with increasing of gas flow rate.

View Publication Preview PDF
Crossref (3)
Crossref
Publication Date
Fri Jan 01 2021
Journal Name
International Journal Of Agricultural And Statistical Sciences
Influence of yeast and intercropping system on growth and yield traits of pea
...Show More Authors

Scopus (9)
Scopus
Publication Date
Sun Aug 06 2023
Journal Name
Journal Of Economics And Administrative Sciences
Probit and Improved Probit Transform-Based Kernel Estimator for Copula Density
...Show More Authors

Copula modeling is widely used in modern statistics. The boundary bias problem is one of the problems faced when estimating by nonparametric methods, as kernel estimators are the most common in nonparametric estimation. In this paper, the copula density function was estimated using the probit transformation nonparametric method in order to get rid of the boundary bias problem that the kernel estimators suffer from. Using simulation for three nonparametric methods to estimate the copula density function and we proposed a new method that is better than the rest of the methods by five types of copulas with different sample sizes and different levels of correlation between the copula variables and the different parameters for the function. The

... Show More
Publication Date
Fri Oct 01 2010
Journal Name
Iraqi Journal Of Physics
Effect of Carbon Black and Water Absorption on Dielectric behavior of EP-modified SiO2 composites
...Show More Authors

Epoxy (EP) – Silica (SiO2) composites are well known composites used in microelectronic industry . So it is important to study their dielectric behavior under different conditions such as
the presence carbon black (UV absorber) and immersion in the water for 30 days .
Dielectric properties were calculated over the frequency range 102 – 106 Hz for epoxy composites with different weight % of micrometer 1.5μm SiO2 particles (60%, 65% and 70wt%) modified with 0.5wt% silane coupling agent to improve adhesion between EP and SiO2 phases .

View Publication Preview PDF
Publication Date
Mon Mar 07 2022
Journal Name
Journal Of Educational And Psychological Researches
Cognitive Behavior Therapy for Depression
...Show More Authors

The current research aimed to identify the cognitive-behavioral therapy on people with depression, through the following hypothesis (there are no statistically significant differences in the sample before and after cognitive-behavioral therapy). The importance of research is highlighted through the use of cognitive-behavioral therapy, to be used in treating depression, anxiety and fears by health institutions. It is also considered as a reference for psychological studies related to this topic to be added to our libraries that already suffer from a scarcity of this type of resources. The cognitive-behavioral therapy was used in the treatment of five male subjects.

The study revealed the existence of statistically significant diff

... Show More
View Publication Preview PDF
Publication Date
Sat Apr 01 2023
Journal Name
Iraqi Journal Of Applied Physics
Calculations of Nuclear Two-Component State Density in Non-Equidistant Spacing Model with Modified Williams
...Show More Authors

Listed

View Publication
Publication Date
Tue Apr 08 2025
Journal Name
Heat Transfer
Experimental Study on the Performance of Gradient Pores Density Metal Foam in a Rectangular Channel
...Show More Authors
ABSTRACT<p>Various approaches are employed to enhance the heat transfer coefficient and Nusselt number inside the channels. One of the techniques employed for these enhancements is the utilization of porous media. In the current article, a practical investigation of forced convection heat transfer in a rectangular cross‐section channel (0.05 × 0.1 m<sup>2</sup>) with 0.25 m length is conducted. A heater with a heat flux range (450–6000 W/m<sup>2</sup>) is imposed under a copper plate, and the other sides are covered by insulation layers. The air is considered as a working fluid with <italic>Re</italic> (600–2100). The test section is fully filled with gradient pore</p> ... Show More
View Publication
Crossref (3)
Crossref