Natural convection in an annular space provided with metal foam fins attached to the inner cylinder is studied numerically. The metal foam fins made of copper were inserted in different axial sections with three fins in each section. The temperature of the inner cylinder is kept constant while the annular outer surface is adiabatic. The thickness effect of the inner pipe wall was considered. Naiver Stokes equation with Boussinesq approximation is used for the fluid regime while Brinkman-Forchheimer Darcy model is used for metal foam. In addition, the local thermal non-equilibrium condition in the energy equation of the porous media is presumed. The effect of Rayleigh number and number of foam fins in the axial direction, on fluid flow and heat transfer characteristics, were examined. The current model was valid with the available published results and good agreement is noticed. Results showed that as the Rayleigh number increases the dominated of convection mode increases and average Nusselt increases. It was found that at Rayleigh of 106 Nusselt reached its higher value which is 4.6 for the case of adding seven axial metal foams. A comparison between adding foam fins and copper fins was established for a range of Rayleigh numbers between 104 and 106. It showed a good enhancement in Nusselt number and the greatest enhancement percentage was 45.9% at Rayleigh equal 106 for the case of using seven sections of foam fins. |
The continuous pressure of work and daily life and the increasing financial and social stress that Iraqi women are experiencing (both inside and outside Iraq) is one of the main causes of anxiety, particularly in those of working class women. This group of women carry the burden of carrying out multiple roles and responsibilities at the same time. All this collectively make them more prone to developing anxiety compared to men. In addition, the physiological and psychological nature of women, as females, on top of the other roles in life, like being a wife or mother or daughter or sister, all add extra pressure on women especially for those who are considered as productive working individuals in the society. In order to study the relatio
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This paper deals with the subject of demarcating as appropriate scientific techniques to rationalize consumption and to control segments of the society for the technical conduct of its handling of the product depending on the mix of elements (product and the volume of demand, Price, promotion and distribution), but inverse manner designed to adjust the working condition of balance between supply and demand and to ensure that rates continue in the marketing process properly, and therefore the research aims to shed light on some of the practices that reflect the Demarketing techniques, As well as the statement of the reality of attitudes towards the practice of those techniques through a sample survey of officials in Baghdad company for so
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Objectives: The study aims to know the effectiveness of the educational program in the patient’s adherence to medication and diet and to know the relationship between the effectiveness of the education program and their demographic data related to the patient’s age, gender, marital status, education level, occupation, monthly income and residence.
Methodology: A quasi -experimental design study was performed on patient who attended to Gastroenterology and Hepatology Teaching Hospital, from March 2021 to September 2021. The non-probability sampling including 50 patients for case study and 30 patients for control group. The questionnaire consists of 3 parts, part one the socio
... Show MoreBN Rashid…, Special Education, 2022
As an alternative to Ordinary Portland Cement (OPC), the alkali-activated binders have been developed with better technical characteristics and more extended durability. The Alkali-Activated Iraqi Natural Pozzolans (AANP) could produce geopolymer cementation building materials and make them ecologically acceptable. The primary advantage of geopolymer cement is that it has a lower environmental effect that contributes to it. The engineering characteristics of geopolymer concrete produced using activated Iraqi natural Pozzolan are summarized in this research. The mechanical properties, modulus of elasticity, and ultrasonic pulse velocity of various concrete mixes were determined via exp
As an alternative to Ordinary Portland Cement (OPC), the alkali-activated binders have been developed with better technical characteristics and more extended durability. The Alkali-Activated Iraqi Natural Pozzolans (AANP) could produce geopolymer cementation building materials and make them ecologically acceptable. The primary advantage of geopolymer cement is that it has a lower environmental effect that contributes to it. The engineering characteristics of geopolymer concrete produced using activated Iraqi natural Pozzolan are summarized in this research. The mechanical properties, modulus of elasticity, and ultrasonic pulse velocity of various concrete mixes were determined via experimental study. The impact of essential variables like w
... Show MoreThis study was carried out to determine the heavy metal accumulation of Juncus rigidus Desfontaines, 1798 from three different regions of the Basrah Province in Southern of Iraq. Specifically, the concentrations of lead, nickel, and cadmium were determined in the roots, culms and leaves of the plant. The results indicated that the highest accumulation of the heavy metal was recorded in lead (Pb) 12.50± 3.58 mg kg-1and then in nickel (< 0.30). The lowest value was recorded for cadmium (< 0.05). As well, lead concentrations in J. rigidus varied in different locations and parts of the plant from undetectable in control to 12.66, 19.33, and 9.80 mg kg-1 in leaves, culm, and roots respective
... Show MorePolarization modulation plays an important role in polarization encoding in quantum key distribution. By using polarization modulation, quantum key distribution systems become more compact and more vulnerable as one laser source is used instead of using multiple laser sources that may cause side-channel attacks. Metasurfaces with their exceptional optical properties have led to the development of versatile ultrathin optical devices. They are made up of planar arrays of resonant or nearly resonant subwavelength pieces and provide complete control over reflected and transmitted electromagnetic waves opening several possibilities for the development of innovative optical components. In this work, the Si nanowire metasurface grating polarize
... Show MoreReducing a structure’s self-weight is the main goal and a major challenge for most civil constructions, especially in tall buildings and earthquake-affected buildings. One of the most adopted techniques to reduce the self-weight of concrete structures is applying voids in certain positions through the structure, just like a voided slab or BubbleDeck slab. This research aims to study, experimentally and theoretically, the structural behavior of BubbleDeck reinforced concrete slabs under the effect of harmonic load. Tow-way BubbleDeck slab of 2500mm×2500m×200mm dimensions and uniformly distributed bubbles of 120mm diameter and 160mm spacing c/c was tested experimentally under the effect of harmonic load. Numerical analysis was als
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