Many researchers used different methods in their investigations to enhance the heat transfer coefficient, one of these methods is using porous medium. Heat transfer process inside closed and open cavities filled with a fluid-saturated porous media has a considerable importance in different engineering applications, such as compact heat exchangers, nuclear reactors and solar collectors. So, the present paper comprises a review on natural, forced, and combined convection heat transfer inside a porous cavity with and without driven lid. Most of the researchers on this specific subject studied the effect of many parameters on the heat transfer and fluid field inside a porous cavity, like the angle of inclination, the presence of vibration, magnetic fields, and heat generation. They used different thermal and hydrodynamic boundary conditions, different geometries of cavity, and different saturated-fluids. Results manifested that the fluid and thermal characteristics enhance greatly as porosity increases at a high value of Darcy number. Also, vibrational effects are a dominant factor in the heat transfer process only at high Darcy and Reynolds numbers.
The characteristic of our time is the tremendous technological progress and the wide use of the Internet. Children have had a large share of this progress.as they are becoming fond of having the technological equipment of tablets and mobile phones which become indispensable for these children cannot do without them .
Recently, the phenomenon of using mobile phones and tablets by children has become more widespread, and the society in general and parents, in particular, have ignored the reasons for their health .Despite the many advantages and benefits for children who are well trained to use these devices properly that have enhanced their cognitive and social abilities, there are many disadvantages that could harm children's growth if
The present work is to investigate the feasibility of removal vanadium (V) and nickel (Ni) from Iraqi heavy gas oil using activated bentonite. Different operating parameters such as the degree of bentonite activation, activated bentonite loading, and operating time was investigated on the effect of heavy metal removal efficiency. Experimental results of adsorption test show that Langmuir isotherm predicts well the experimental data and the maximum bentonite uptake of vanadium was 30 mg/g. The bentonite activated with 50 wt% H2SO4 shows a (75%) removal for both Ni and V. Results indicated that within approximately 5 hrs, the vanadium removal efficiencies were 33, 45, and 60% at vanadium loadings of 1
... Show MoreLaser cleaning of materials’ surfaces implies the removal of deposited pollutants without affecting the material. Nanosecond Nd:YAG pulsed laser, operating at 1064 nm and 532nm, was utilized. Different laser intensities and number of pulses were used on metallic and non-metallic surfaces under O2 and Ar environments to remove metal oxide and crust. Cleaning efficiency was studied by optical microscope. The results indicated the superiority of 1064 nm over the 532 nm wavelength without any detectable damage to materials’ surfaces. Marble cleaned in Oxygen gas environment was better than in Ar gas.
The study discusses ''The Security Intellectual Proposals of the Paris and the Welsh Schools'', which are considered one of the most important contemporary European monetary schools that emerged in the nineties of the twentieth century, and how did it approach the concept of security, criticizing the traditional trend that prevailed during the Cold War period regarding limiting the concept of security to the state or to the military aspect (National Security), and an attempt to expand the concept to economic, social and environmental dimensions, as well as political and military dimensions. The most important proposals that the Wales School provided are “Security as an emancipation policy”, “ individual security”, and “The ro
... Show MoreResearch summary
This research discloses the study of the methodology of one of the notables of the followers, which is: (Abi Mijlis Al-Basri), who had a clear impact on many commentators after him, especially in the field of interpretation by impact. This study included two topics:
The first: his biography and scientific
The second: his methodology in the traditional interpretation.
Andalusian literature is a literature in itself that is influenced and influenced, and it did not come out of thin air. Muslim Arabs came from the East to this country for jihad and a desire to live, and they carried with them their beliefs, customs and traditions. They must blend in the new element and its environment, so interference, fusion, diversity and influence actually took place.
It seems to us that the Arabs in the era of the governors in Andalusia (92-138 AH) strived hard to preserve everything that is Eastern. Literature is an oriental model in the content of prose and poetry, but in the era of the Umayyad emirate, we will notice that the environment, the development of ages, and the mixing of civilizations have an effect
Arabian Political Regimes: Problems of Policies and Rule; An Introduction to Interpreting (The Arabian Spring) The Arab Region witnessed, since 2011, critical changes overthrew a group of Arab regimes in some of its countries, and the reaction of these changes are still going on up to now. These changes were given lots of justifications and interpretations. The current study tries to concentrate on the most important problems which were due to what was known as (The Arab Spring). The study proposes that the crisis which the countries of the area are exposed to is not spontaneous in many of its aspects. It is totally a crisis of rule and policies. Because it is a reflection of the nature of authority in the Arabian regimes on the one hand
... Show MoreThe theatrical performance has an aesthetic, artistic, technical and intellectual vision presented by the theatrical director according to the dualities of theatrical form and content, which depend on the uniformity and interconnection of theatrical elements, as the vision is integrated through the harmony and fusion of these elements and the flow of their coordination with an aesthetic system within the framework of the aesthetic space of the theatrical performance, and when the heritage is presented in the performance, as there will certainly be different readings of that heritage and moving away from the iconization of the event and highlighting it in a manner that is in line with the spirit of the age.
the (researcher) tries, t
In this contribution, density functional theory-based calculations have been carried out to assess the electronic, photocatalytic and optical properties of Ce1-xTixO2 system. Ti incorporation leads to a decrease of Ce 4f states and enhancement of Ti 3d states in the bottom of conduction band. Furthermore, it was found that doping ceria with Ti-like transition metals could evidently shift the absorption of pure CeO2 towards higher wavelength range. These findings can provide some new insights for designing CeO2-based photocatalysts with high photocatalytic performance. To the best of our knowledge, this investigation calculates Mullikan’s charge transfer of Ce1-xTixO2 system for the first time. Charge transfer reveals an ionic bond between
... Show More