Preferred Language
Articles
/
ijp-461
The influence of various pH values on the aerogel physical properties by sol-gel technique
...Show More Authors

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.

Crossref
View Publication Preview PDF
Quick Preview PDF
Publication Date
Tue Oct 02 2018
Journal Name
Iraqi Journal Of Physics
Preparation of unsaturated polyester/nano ceramic composite and study electric, thermal and mechanical properties
...Show More Authors

The composites were manufactured and study the effect of addition of filler (nanoparticles SiO2 treated with silane) at different weight ratios (1, 2, 3, 4 and 5) %, on electrical, mechanical and thermal properties. Materials were mixed with each other using an ultrasound, and then pour the mixture into the molds to suit all measurements. The electrical characteristics were studied within a range of frequencies (50-1M) Hz at room temperature, where the best results were shown at the fill ratio (1%), and thermal properties at (X=3 %), the mechanical properties at the filler ratio (2%).

View Publication Preview PDF
Crossref (11)
Crossref
Publication Date
Sun Dec 06 2009
Journal Name
Baghdad Science Journal
Preparation of Electrical Conducting Polymer CompositesFrom Polyvinylchloride (PVC) Resin and StudyingSome its Electrical Properties
...Show More Authors

The D.C electrical and thermoelectrically properties of randomly mixed isolator – electrolyte system as (Al/ PVC – LiF/Al) junction consisting of polyvinyl chloride (PVC)resin reinforced with Lithium Fluoride (LiF) powder were studied. A comparison is made the properties of (PVC) material with varying percentage of (LiF) powder (0%, 30%, 50%, 80%)to find out the effect of reinforcement of isolator material. The composites dissolving in 10ml form tettraHaedroflourn (THF) and Solution were the castled in Petri dish and Laved it dry in the air, The out coming Sample were disc - Like shape of a diameter of about 3cm and thickness reneged between (0.01- 0.018) cm . The composites dissolving in 10ml form tettraHaedroflourn (THF) a

... Show More
View Publication Preview PDF
Crossref
Publication Date
Wed Jun 01 2016
Journal Name
Chalcogenide Letters
Characterization, morphology and electrical properties of chemically deposited nanocrystalline PbS/Si heterojunction thin films
...Show More Authors

A nanocrystalline thin films of PbS with different thickness (400, 600)nm have been prepared successfully by chemical bath deposition technique on glass and Si substrates. The structure and morphology of these films were studied by X-ray diffraction and atomic force microscope. It shows that the structure is polycrystalline and the average crystallite size has been measured. The electrical properties of these films have been studied, it was observed that D.C conductivity at room temperature increases with the increase of thickness, From Hall measurements the conductivity for all samples of PbS films is p-type. Carrier's concentration, mobility and drift velocity increases with increasing of thickness. Also p-PbS/n-Si heterojunction has been

... Show More
Publication Date
Wed Jan 01 2020
Journal Name
Materials Science And Engineering
Fresh and Hardened Properties of Nano Self-Compacting Concrete with Micro and Nano Silica
...Show More Authors
Abstract<p>Self-compacting concrete (SCC) has undergone a remarkable evolution recently based on the results from several studies that have indicated the chain of benefits SCC provides. Micro and nano materials used as mineral additives in SCC offer several high-performance properties, and this research studies the effects of micro silica (MS) (10%, used as a reference) and colloidal nano-silica (CNS) (2.5%, 5%, 7.5%, and 10%) on the fresh and hardened properties of SCC. All mixtures were estimated using flow, L-box, and V-funnel tests to examine workability and compressive strength, modulus of elasticity and tensile strength as hardened properties. The use of CNS increased the overall compressi</p> ... Show More
Preview PDF
Scopus (18)
Crossref (13)
Scopus Crossref
Publication Date
Fri Jan 01 2016
Journal Name
Journal Of Engineering
Some Properties of Polymer Modified Self-Compacting Concrete Exposed to Kerosene and Gas Oil
...Show More Authors

This thesis aims to study the effect of addition polymer materials on mechanical properties of self-compacting concrete, and also to assess the influence of petroleum products (kerosene and gas oil) on mechanical properties of polymer modified self-compacting concrete (PMSCC) after different exposure periods of (30 ,60 ,90 ,and 180 days).

Two type of curing are used; 28 days in water for SCC and 2 days in water followed 26 days in air for PMSCC.

The test results show that the PMSCC (15% P/C ratio) which is exposed to oil products recorded a lower deterioration in compressive strength's values than reference concrete. The percentages of reduction in compressive strength values of PMSCC (15% P/C ratio) was

... Show More
View Publication Preview PDF
Publication Date
Sun Jun 01 2014
Journal Name
Baghdad Science Journal
Study of Fatigue and Bending Properties For Epoxy / Kevlar - Glass Fibers and Hybrid Composite
...Show More Authors

In this research a study of the effect of quality, sequential and directional layers for three types of fibers are:(Kevlar fibers-49 woven roving and E- glass fiber woven roving and random) on the fatigue property using epoxy as matrix. The test specimens were prepared by hand lay-up method the epoxy resin used as a matrix type (Quick mast 105) in prepared material composit . Sinusoidal wave which is formed of variable stress amplitudes at 15 Hz cycles was employed in the fatigue test ( 10 mm )and (15mm) value 0f deflection arrival to numbers of cycle failure limit, by rotary bending method by ( S-N) curves this curves has been determined ( life , limit and fa

... Show More
View Publication Preview PDF
Crossref
Publication Date
Fri Jun 01 2018
Journal Name
Materials Science-poland
Thermal and electrical properties of polyimide/PANI nanofiber composites prepared via in situ polymerization
...Show More Authors
Abstract<p> Polyimide/polyaniline nanofiber composites were prepared by in situ polymerization with various weight percentages of polyaniline (PANI) nanofibers. X-ray diffraction (XRD) and Fourier transform infrared spectra (FT-IR), proved the successful preparation of PANI nanofiber composite films. In addition, thermal stability of PI/PANI nanofiber composites was superior relative to PI, having 10 % gravimetric loss in the range of 623 °C to 671 °C and glass transition temperature of 289 °C to 297 °C. Furthermore, the values of the loss tangent tanδ and AC conductivity σAC of the nanocomposite films were notably higher than those of pure polyimide. The addition of 5 wt.% to 15 wt.% PANI</p> ... Show More
View Publication
Scopus (41)
Crossref (37)
Scopus Clarivate Crossref
Publication Date
Wed Sep 29 2021
Journal Name
College Of Islamic Sciences
the purposes of belief The concept of the purposes of belief and its importance: The first requirement: the concept and the aim of contractual purposes, The second requirement: the importance of nodal purposes
...Show More Authors

 

Abstract

This research deals with the definition of the concept of nodal purposes, And what is related to it, from its aim and importance, And for the purposes of the importance of Streptococcus In trying to understand the nodal truths For different minds, Especially with those who object to the introduction of belief in purposes studies, This research has two requirements:

 The first requirement: the concept and the aim of contractual purposes,It consists of two branches, The first is in the concept of nodal purposes, And it dealt with the definitions in terms of language and terminology And what we see is proportional to what aim

... Show More
View Publication Preview PDF
Publication Date
Sun Dec 01 2013
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
The impact of the strengths and weaknesses in Iraqi newspapers: The evolution of the consumer - the reader
...Show More Authors

The first section of this research discussed  the manner of the research from many sides like the problem it faces, importance of it , its targets ,boundaries, the way to collect and get information's and its assumption.

When the second chapter discussed the press – manufacturing and the development ,importance and types of newspapers, also its merits and weaknesses.

The third chapter talked about the scientific side and how to choose an assumption for the research . as it talked also about the apparent honest and stability tests that help in analyzing the research until getting results and so the right assumption for  the research will be chosen.

And finally, the fourth chapter put highlight on the be

... Show More
View Publication Preview PDF
Publication Date
Wed Jun 01 2022
Journal Name
Political Sciences Journal
The nature of the relationship between the states and the union in the United States of America
...Show More Authors

Knowing the nature of the relationship in federal systems lies in studying the political, social, economic and cultural forces, for their role in laying the foundations and the federal system. No matter how important the pillars of that system are, and through this research, we will learn how the political elites were able to crystallize this unique system, until it became one of the political systems that some countries seek to copy and apply its experience.

View Publication Preview PDF
Crossref