PREDICTION OF THREE DIMENSIONAL NATURAL CONVECTION FROM A HORIZONTAL ISOTHERMAL SQUARE PLATE

A theoretical study of a three-dimensional natural convection heat transfer from an isothermal horizontal square plate, with upper and lower heated surfaces is present. The transient Navier–Stokes and energy equations were solved by using finite deference method (F.D.M). The complete Navier–Stokes equations are transformed and expressed in terms of vorticity–vector potential and solved using an Alternating Direction Implicit (ADI) method for the parabolic portion of the problem, and Successive Over–Relaxation (SOR) method for the elliptic portion .A computer program in (FORTRAN 77) was built to carry out the solution. The numerical results were obtained for laminar flow range of Grashof number up to (105) in up ward–facing and downward–facing with Prandtl number of (0.72). The results of local Nusselt number have maximum values at the outer edge of plate for two cases upward and downward facing heating. The comparison of the results of average Nusselt number with numerical data for downward facing and experimental data for upward facing shows acceptable agreement. It may be noted that the present data are generally different with experimental data, since the available data are extrapolated to high Grashof number. Thus the deviation may be large with present data

ISOLATION OF ASTRAGALIN FROM IRAQI CHENOPODIUM ALBUM

Objective: Chenopodium album L is the species of the genus chenopodium. The Greek name Chenopodium means goosefoot. The plant is native to Asia and Europe. The analysis of the constituents of the Iraqi plant was performed using gas chromatography and high-performance liquid chromatography techniques.Methods: Thin-layer chromatography (TLC) and high-performance TLC chromatographic techniques were used for the detection and isolation of the active constituent found in the plant. Spectral analysis such as nuclear magnetic resonance (NMR) and UV was used to confirm the chemical structure of the compound isolated.Results: Astragalin was isolated and identified by comparison with standard kaempferol 3-O-β-glucoside (astragalin) which was detected as the major glycoside in the polar fraction of the plant. Further, identification of the compound was performed by 1H-NMR spectroscopy.Conclusion: Astragalin is the major flavonoid glycoside found in the plant.Â

Performance of microstrip patch antenna for single and array element with and without EBG

In this paper, a compact single patch antenna and microstrip array antenna with EBG structures at 6 GHzhave been compained. A surface wave effect is often considered undesirable, since it increased the side lobes, and decreased the antenna gain and effeciency. This problem can be solved by utilizing EBG to suppress of such waves. Above the antenna substrate, the mushroom-like EBG were proposed. The side lobes have been improved from −6.8 dB to −16.5 dB, and better directivity was achieved from 5.77 dBi to 10 dBi and the efficiency improved from (80%) to 95% by using EBG with rectangular antenna. Additionally, the array antenna radiation pattern with EBG was improved to −23.5 dB, and the directivity and effeciency have been improved to 14.3 dBi and to 91.5 respctively. These antenna structures have a great eventuality for use in C band application

Sparse Suffix and LCP Array: Simple, Direct, Small, and Fast

Sparse suffix sorting is the problem of sorting $b=o(n)$ suffixes of a string of length $n$. Efficient sparse suffix sorting algorithms have existed for more than a decade. Despite the multitude of works and their justified claims for applications in text indexing, the existing algorithms have not been employed by practitioners. Arguably this is because there are no simple, direct, and efficient algorithms for sparse suffix array construction. We provide two new algorithms for constructing the sparse suffix and LCP arrays that are simultaneously simple, direct, small, and fast. In particular, our algorithms are: simple in the sense that they can be implemented using only basic data structures; direct in the sense that the output arrays are not a byproduct of constructing the sparse suffix tree or an LCE data structure; fast in the sense that they run in $\mathcal{O}(n\log b)$ time, in the worst case, or in $\mathcal{O}(n)$ time, when the total number of suffixes with an LCP value greater than $2^{\lfloor \log \frac{n}{b} \rfloor + 1}-1$ is in $\mathcal{O}(b/\log b)$, matching the time of the optimal yet much more complicated algorithms [Gawrychowski and Kociumaka, SODA 2017; Birenzwige et al., SODA 2020]; and small in the sense that they can be implemented using only $8b+o(b)$ machine words. Our algorithms are simplified, yet non-trivial, space-efficient adaptations of the Monte Carlo algorithm by I et al. for constructing the sparse suffix tree in $\mathcal{O}(n\log b)$ time [STACS 2014]. We also provide proof-of-concept experiments to justify our claims on simplicity and efficiency.Comment: 16 pages, 1 figur

Performance of combined tillage equipment and it’s effect on soil properties

An experiment was conducted to evaluate the performance of a locally manufactured combined tillage implement (moldboard plow + ripper) in one of the fields of the kufa university faculty of agriculture. The experiment was included two factors , the first factor is combing the ripper to mold board plow in five level these are fixing the combined ripper shanks while the shanks points oriented in two different levels with and opposite to the plowing direction , two levels of different ripper depths the same depth and 5 cm above the depth of mold board plow share and the fifth level is control treatment ( mold board plow alone ) .The second factor was the plowing operation speed at five levels (1.4, 2.0 , 3.6 and 4.7) Km.hr ̵ ¹ . the experiment was conducted as a factorial experiment with RCBD , the LSD test at 5 % was used to compare between means .The results of the research were showed that combining the locally manufactured ripper implement to mold board plow resulted in significant increase in the number of soil clods with the desired diameter (5-10 cm ) very low number of soil block with diameter larger than 10 cm , more even soil roughness and the actual productivity has not decreased to the extent that it affects the efficient performance of the tillage process compared to the use at the mold board plow alone