هناك عوامل عديدة تؤثر في البنية الشكلية للم ا ركز الحضرية التي تشهد تحولات وبصورة مستمرة ومع
توسع المدينة ونموها تفقد هذه الم ا ركز لمقومات بنيتها الحضرية المتكاملة بسبب تلك التحولات الحاصلة
ضمنه وبصورة ديناميكية من اضافات وتغيرات في النمط الحضري الذي يتشكل من عدة نماذج معمارية
جديدة مؤثرة ولأجل ذلك جاء البحث لايضاح اثر هذه العلاقة بين النمط الحضري والنموذج المعماري
وتحولاته في تكاملية البنية الشكلية للمراكز الحضرية والتوصل لتشخيص مشكلة البحث الرئيسية(أثر
(اضافة النموذج المعماري ضمن النمط الحضري في تحقيق بنية شكلية متكاملة للمركز الحضري
ولحل هذه المشكله فأن تحديد الاسباب يقتضي البحث في تحولات النمط الحضري واسباب التحول واثر
اضافة النموذج المعماري، فتمثلت فرضية البحث بـ(تحدث التحولات الشكلية في الم ا ركز الحضرية نتيجة
ظهور مستمر للنموذج المعماري ضمن النمط الحضري الحركي الوظيفي ) ليتوصل البحث الى مجموعة
من الاستنتاجات اهمها (يمكن تحقيق مراكز حضرية متكاملة شكليا ووظيفيا من خلال خلق انماط حضرية
ذات معاني جديدة مؤثرة ومتميزة تركيبيا عن المحيط الحضري بنماذج معمارية ذات وظائف جديدة متعددة
(الاستعمال منسجمة ومتوافقة مع روح العصر
تأثير علاقة النمط الحضري مع النموذج المعماري في تكاملية البنية الشكلية للمراكز الحضرية
النمط الحضري
النموذج المعماري
البنية الشكلية الحضرية
تكاملية البنية الشكلية
Urban pattern
architectural model
urban formal structure
formal structure integration
Publication Date
Sun Jan 20 2019
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
Novel Co-Precipitation method for synthesis of Nanostructured Nickel Oxide in accordance to PH: Structural and Optical Properties as an Active optical filter
Low cost Co-Precipitation method was used for Preparation of novel nickel oxide (NiO) nano particle thin films with Simple
with two different PH values 6
12 and its effect on structural and optical properties as an active optical filter. Experimental results of structural properties X-ray diffraction (XRD) showed that both Nickel oxide nanoparticles with (PH=6 and 12) have polycrystalline structure smaller average particle size about 8.5 nm for PH=6 in comparison with PH=12. Morphological studies using Scanning electron microscopy (SEM) and atomic force microscope (AFM) show uniform nano rod distribution for PH=6 with smaller average diameter
average roughness as compared with NiO with PH=12 that showed larger diameter
grain size
spherical shape with scope of excellent sensing applications due to high roughness .Optical properties results Show blue shift for PH=6 as compared with PH=12m leading to potential of optoelectronic applications and as active optical Key words: Nickel Oxide
Co-precipitation method
PH
particle size
nanostructure.
Low cost Co-Precipitation method was used for Preparation of novel nickel oxide (NiO) nano particle thin films with Simple, with two different PH values 6, 12 and its effect on structural and optical properties as an active optical filter. Experimental results of structural properties X-ray diffraction (XRD) showed that both Nickel oxide nanoparticles with (PH=6 and 12) have polycrystalline structure smaller average particle size about 8.5 nm for PH=6 in comparison with PH=12. Morphological studies using Scanning electron microscopy (SEM) and atomic force microscope (AFM) show uniform nano rod distribution for PH=6 with smaller average diameter, average roughness as compared with NiO with
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Publication Date
Mon Nov 01 2010
Journal Name
Al-nahrain Journal Of Science
Chemical Elements Diffusion in the Solar Interior
The standard solar model and equation of state have been used to study relative diffusion of Hydrogen and Helium in the present time for solar interior
as a function of distance and depth from the center of the star. The effects of temperature and density on diffusion velocity for these chemical elements have been explaned.
It is found that heat flow which is arising from these reactions leads to an increase in helium diffusion velocity
while the temperature and density leading to a decrease in Hydrogen diffusion velocity. This means that Hydrogen behaves inversely with that for helium does through these reactions. Accordingly
diffusion percentages for Hydrogen
Helium and other Heavy Elements could be determined for the main sequence stars and white dwarf stars.
Publication Date
Fri Jul 29 2022
Journal Name
Journal For Vascular Ultrasound
A Comparative Study of the Right and Left Carotid Arteries in Relation to Age for Patients With Diabetes and Hypertension
Introduction:
Introduction: Age
hypertension
and diabetes can cause significant alterations in arterial structure and function
including
changes in lumen diameter (LD)
intimal-medial thickness (IMT)
flow velocities
and arterial compliance. These are also considered
risk markers of atherosclerosis and cerebrovascular disease. A difference between right and left carotid artery blood flow and
IMT has been reported by some researchers
and a difference in the incidence of nonlacunar stroke has been reported between
the right and left brain hemispheres. The aim of this study was to determine whether there are differences between the right and
left common carotid arteries and internal carotid arteries in patients with hypertension and diabetes for 2 age groups.
Methods: We studied 250 patients with both diabetes and hypertension. Patients were divided into 2 age groups with the
old age group being 56 to 75 years and the young age group 35 to 55 years. The bilateral common carotid and internal carotid
arteries were evaluated with B-mode ultrasound and Doppler examinations. The LD and IMT were measured for both common
carotid arteries
and spectral waveform parameters and indices were recorded for both internal carotid arteries.
Results: The difference in LD between the left and right common carotid arteries for the old age group was 11.64% and for the
young age group was 6.42%
with significant P values of <.05 for both age groups. The difference in IMT between the left and
right common carotid arteries was 18.27% in the old age group compared with 15.38% in the young age group
with significant
P values of <.05. There was a difference in peak systolic velocity between the left and right internal carotid arteries of 4.85%
in the old age group which was not significant
compared with 14.28% in the young age group with a significant P value <.05
whereas the difference in end-diastolic velocity between the left and right internal carotid arteries was not significant for both
age groups. Differences between the right and left internal carotid arteries for resistive index
pulsatility index
and pressure
gradient were significant only in the young age group.
Conclusion: We found significant differences between the right and left common carotid and internal carotid arteries in
patients with diabetes and hypertension which were more prominent in the young age group. Values for common carotid IMT
and LD were significantly higher in the left common carotid artery versus the right common carotid artery in both age groups.
Differences between the 2 carotid sides may be attributed to anatomic variations in the common carotid artery origins which
lead to differences in stress between the 2 sides
Age, hypertension, and diabetes can cause significant alterations in arterial structure and function, including changes in lumen diameter (LD), intimal-medial thickness (IMT), flow velocities, and arterial compliance. These are also considered risk markers of atherosclerosis and cerebrovascular disease. A difference between right and left carotid artery blood flow and IMT has been reported by some researchers, and a difference in the incidence of nonlacunar stroke has been reported between the right and left brain hemispheres. The aim of this study was to determine whether there are differences between the right and left common carotid arteries and internal carotid arteries in patient
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(2)
Publication Date
Fri Mar 01 2019
Journal Name
Applied Acoustics
Theoretical model of absorption coefficient of an inhomogeneous MPP absorber with multi-cavity depths
Micro-perforated panel (MPP) absorber has been known as an alternative absorber to classical porous material given its facile installation
long durability
environmental friendliness and attractive appearance. Extensive studies of MPP absorber proposing the improvement of its absorption frequency bandwidth have been published. This study presents a MPP absorber introduced with inhomogeneous perforations and with multi-cavity depths. The MPP is divided into two sub-area
where each area has different hole diameter
perforation ratio and a separated backed cavity depth. The acoustic impedance is modelled using electrical equivalent circuit and the absorption coefficient is calculated under normal-incidence of sound. It is found that the inhomogeneous MPP can have good bandwidth of absorption by designing the sub-MPP of smaller perforation ratio with large hole diameter and the one having the larger perforation ratio with smaller hole diameter. The absorption bandwidth can be conveniently controlled by adjusting the cavity depth of each sub-MPP. The results from the experimental work show good agreement with the theoretical model.
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