15 research outputs found
Experimental Study For a Laminar Natural Convection Heat Transfer From an Isothermal Heated Square Plate With and Without Circular Hole
No full textAn experimental investigation of natural convection heat transfer from an isothermal horizontal,vertical and inclined heated square flat plates with and without circular hole, were carried out in two cases, perforated plates without an impermeable adiabatic hole "open core" and perforated plates with an impermeable adiabatic hole "closed core" by adiabatic plug. The experiments covered the laminar region with a range of Rayleih number of (1.11x106 ≤RaLo≤4.39x106 ), at Prandtle number (Pr=0.7). Practical experiments have been done with variable inclination angles from horizon (Ф=0o ,45o,90o,135oand 180o),facing upward (0o≤Ф<90o), and downward (90o
≤Ф<180o). The results showed that the temperature gradient increases while the thermal boundary layer thickness decreases when Grashof number and perforation ratio (m) increase . The temperature gradient for inclined position facing upward is less than facing downward,while the thermal boundary layer thickness is greater. The temperature gradient decreases while the thermal boundary layer thickness increases for perforated plates with an adiabatic core as compared with perforated plates without an adiabatic core. The value of average Nusselt number increases with increasing perforation ratio, and Grashof number for all specimens with and without an adiabatic core, also increases by increase in inclination of plates approaching the higher value at vertical position (Ф=90o
), then decreases with increasing inclination of plates till horizontal position (Ф=180o). The average Nusselt number values for perforated plates with an adiabatic core are lower than for perforated plates without an adiabatic core for all perforation ratios. Maximum heat transfer rate occurs at perforated plate with perforation ratio of (m=0.1) without adiabatic core for vertical position (Ф=90o), at a range of Grashof number (1.576x106≤GrLo≤6.292x106 ), while the rate of heat transfer decreases with increasing perforation ratio for plates with and without adiabatic core for decrease in heat transfer rate area. The rate of heat transfer for
perforated plates with circular hole is more than for perforated plates with square hole at the same perforation ratios (m=0.1,0.16,0.24 and 0.36). It found that the lack of core flow decreases the overall heat transfer rate by (6.477%) . There was a good agreement for the experimental present work results compared with other pervious results .
NUMERICAL STUDY FOR A THREE DIMENSIONAL LAMINAR NATURAL CONVECTION HEAT TRANSFER FROM AN ISOTHERMAL HEATED HORIZONTAL AND INCLINED SQUARE PLATE AND WITH A CIRCULAR HOLE
No full textA theoretical study for a three-dimensional natural convection heat transfer from an isothermal horizontal , vertical and inclined heated square flat plates (with and without circular hole) has been done in the present work. The study involved the numerical solution of the transient Navier-Stokes and energy equations by using finite deference method (F.D.M.). The complete Navier-Stokes
equation are transformed and expressed in terms of vorticity-vector potential. The Energy and Vorticity equations were solved by using an Alternating Direction Implicit (ADI) method because they are transient equations of parabolic portion, and the Vector potential is solved by using an equations Successive Over-Relaxation (S.O.R) method because it is from elliptic portion. The
numerical solution is capable of calculating the Vector potential, three components of Vorticity and temperature field of the calculation domain. The numerical results were obtained in rang of Grashof number (103≤Gr≤5x104 ) with Prandtl number of (0.72) for square flat plate and the other consist a circle hole with ratio 0.6 and 0.8 diameter of the hole to main square side length. The numerical results showed that the main process of heat transfer is conduction for Grashof number less than 103 and convection for Grashof number larger than 103 and the results of local Nusselt number show fairly large dependence on inclination angle. For horizontal plate facing upward and downward, average Nusselt number is proportional to one-fifth power of Rayleigh number, and there is a significant difference in heat transfer rates between the upward and downward cases. For horizontal plate with circle hole facing upward for Grashof number 104 , the effect of core portion caused a limited increment in the heat transfer rate, where as for the facing downward case, the effect was larger and the maximum value of heat transfer rates is be for square flat plate with circle hole by ratio 0.6 for all inclination angles. With the increase of Grashof number to 5x104 heat transfer rates decrease except the square horizontal flat plate with circle hole by ratio 0.6 . The average Nusselt number increases with the increase of inclination of plates facing upward to reach to the higher average Nusselt number at vertical position then decrease with increase of inclination of plates. And the maximum value of average Nusselt number is depended on the ratio of diameter of the hole to main square side length, showed that the maximum temperature gradient occurs at the external edge of the horizontal plate (with and without circle hole) facing upward and at the lower external edge in inclined case. The numerical results was made through comparison with a previous numerical and experimental work, the agreement was good.
NATURAL CONVECTION FROM SINGLE FINNED TUBE IMMERRSED IN A TILTED ENCLOSURE
No full textHeat transfer rates of a single horizontal finned tube immersed in water –filled enclosure tilted at
30 degrees are measured .The results serve as a baseline case for a solar water heating system with a heat exchanger immersed in integral collector storage. Tests were made with both adiabatic and uniform heat flux boundary conditions. Natural convection flow in enclosure is interpreted from measured water temperature distributions. Formation of an appropriate temperature difference that drives natural convection is determined .Correlations for the overall heat transfer coefficient in terms of the Nusselt and Rayleigh numbers are reduced to the form Nu=0.716 Ra 0.247 Based on the diameter of the immersed tube .Comparison the present work
results with others gave a good agreemen
NUMERICAL AND EXPERIMENTAL INVESTIGATION ON THE EFFECT OF RESTRICTION SHAPE ON CHARACTERISTICS OF AIRFLOW IN A SQUARE DUCT
No full text Experimental and numerical investigation has been under taken to study turbulent flow of air through duct using restriction in different shapes and positions for Reynolds numbers ranges of (8.2x104 → 5.6x104).The numerical approach used in this work is the finite volume method for solution of elliptic partial differential equation for the modeling of turbulent (k-) model as well as wall function concept near the wall which was used to take the turbulent effects into consideration have been employed.The experimental test rigs were constructed from Perspex, and a fivehole pressure probe was used to measure the three component of air flow velocity vector in space.The results show that the total pressure drop depends on the shape and position of the restriction, and the pressure drop coefficient due to the restriction shape and position (kR) depends on two parameters; blockage area ratio (Ab) and the ratio between wetted perimeter to the free remainder perimeter (pe/Pe) and dose not depend on the Reynolds number ( for the same blockage area ratio Ab if the pe/Pe increases 40%, the coefficient kR increases 7% , and for the same pe/Pe, if the blockage area ratio increases 50% ,the coefficient kR increases 10%). But the pressure drop coefficient due to the friction (Cf) is a function of Reynolds.
EXPERIMENTAL STUDY ON THE PRESENCE OF OPEN CAVITY EFFECTS ON INTERNAL FLOW AND CONVECTIONHEAT TRANSFER CHARACTERISTICS
No full textAn experimental study is conducted to investigate the effect of open cavity on the pattern of fully developed internal flow and convection heat transfer. In this experimental work the velocity profile, temperature distribution, heat transfer coefficient and Nusselt number were determined at various Reynolds numbers (1.9*104≤ Re ≤ 2.7*104
) for smooth surface as well as for flow over open cavity (with and without excitation). The results showed that the presence of the cavity led to change the downstream velocity profile and the dissimilarity of downstream skin friction coefficient between the upper and lower surfaces around (64 %) at distance to the length cavity (x/L= + 20.5). As a result the heat transfer coefficient and Nu increased downstream of the cavity especially at (x/L= + 20.5) around (30 %). The effect of cavity excitation with different sound levels (100,107.5 and 115) dB and frequencies (25,50 and 100) Hz was small compared with the cavity itself.
Author Correction: COVID-19 infection segmentation using hybrid deep learning and image processing techniques
No full textCorrection: Epidemiology and outcomes of early-onset AKI in COVID-19-related ARDS in comparison with non-COVID-19-related ARDS: insights from two prospective global cohort studies (Critical Care, (2023), 27, 1, (3), 10.1186/s13054-022-04294-5)
No full textFollowing publication of the original article [1], the authors identified that the collaborating authors part of the collaborating author group CCCC Consortium was missing. The collaborating author group is available and included as Additional file 1 in this article
Wafer classification using support vector machines
No full textIncreasing yield is a primary concern to integrated circuit manufacturing companies as it dictates the readiness of a new process for high volume manufacturing. In order to expedite the process of discovering yield issues, companies have started looking for ways to perform early prediction for such issues. This paper suggests the use of the support vector machines (SVMs) for early wafer classification. The choice of SVM is motivated by the model's ability to effectively classify multivariate, multimodal, and inseparable data points. This model uses multidimensional hyperplanes to separate and classify wafers into low-yield and high-yield classes. This paper includes a proposal for how the classification model can be applied for yield classification and how it can be adaptively updated in a manufacturing environment. We show how the values for the SVM parameters can be selected for best yield classification. Furthermore, performance evaluation is conducted on real manufacturing data, comparing the proposed SVM classifier to state of the art. Results show that in all cases, SVM consistently outperforms other methods with and without adaptive model updates. The experiments also show that all classifiers' performances depend on yield thresholds. It is also shown that the classification model can be built and executed using a reduced set without compromising its accuracy. © 1988-2012 IEEE.Abe S., 2005, SUPPORT VECTOR MACHI; Boser B, 1992, P 5 ANN WORKSH COMP, V5, P144, DOI DOI 10.1145-130385.130401; Botros Y, 2003, P SOC PHOTO-OPT INS, V5044, P121, DOI 10.1117-12.485311; Botros Y., 2003, P AEC APC S 4; Chapelle O, 2002, MACH LEARN, V46, P131, DOI 10.1023-A:1012450327387; Chin W. W., 2010, HDB PARTIAL LEAST SQ; Dasarathy B. V., 1991, NEAREST NEIGHBOR NN; Dupret Y., 2005, P IEEE SEM ADV SEM M, P118; Fayed A., 2003, P AEC APC S 25 SEP; Fenner J., 2000, P AEC APC S 12 SEP, VXII; Hajj H., 1998, P FLEX AUT INT MAN C; Hajj H., 2006, P AEC APC S 18, VXVIII; Hajj H, 2007, P SOC PHOTO-OPT INS, V6730, pQ7300, DOI 10.1117-12.746844; Hall M., 2000, P 17 INT C MACH LEAR, P359; Han J., 2001, DATA MINING CONCEPTS; He QP, 2008, P AMER CONTR CONF, P1606, DOI 10.1109-ACC.2008.4586721; He QP, 2007, IEEE T SEMICONDUCT M, V20, P345, DOI 10.1109-TSM.2007.907607; Khan AA, 2008, J PROCESS CONTR, V18, P961, DOI 10.1016-j.jprocont.2008.04.014; Kittler R., 2000, P INT C MOD AN SEM M, P270; Li TS, 2006, J INTELL MANUF, V17, P355, DOI 10.1007-s10845-005-0008-7; Lin TH, 2009, IEEE T SEMICONDUCT M, V22, P204, DOI 10.1109-TSM.2008.2011185; MACGREGOR JF, 1995, CONTROL ENG PRACT, V3, P403, DOI 10.1016-0967-0661(95)00014-L; May G. S., 2006, FUNDAMENTALS SEMICON; Moore G. E., 1975, P IEEE INT EL DEV M, P11; Moyne J, 2001, RUN TO RUN CONTROL S; Moyne JR, 2007, IEEE T SEMICONDUCT M, V20, P408, DOI 10.1109-TSM.2007.907617; Quinlan J. R., 1993, C4 5 PROGRAMS MACHIN; SPECHT DF, 1991, IEEE T NEURAL NETWOR, V2, P568, DOI 10.1109-72.97934; Wong A. Y., 1996, Proceedings. 1996 IEEE International Symposium on Defect and Fault Tolerance in VLSI Systems (Cat. No.96TB100081), DOI 10.1109-DFTVS.1996.57201274
IN-VITRO ANTICOAGULANT EFFECT OF AERIAL PARTS EXTRACTS OF YEMENI FAGONIA SCHWEINFURTHII HADIDI
No full textBackground: Blood coagulation is a quick and effective process that results in the creation of clots, which demands to monitor. Many illness disorders include an abnormality in blood coagulation. This study examined the in vitro effects of methanol, ethyl acetate, and n-hexane extracts from aerial parts of Fagonia schweinfurthii Hadidi on healthy human volunteers' blood coagulation. 
Methods: The Secondary metabolites were extracted from dried and crushed F. schweinfurthii aerial parts using n-hexane, ethyl acetate, and methanol, respectively. Additionally, the extracts were tested in vitro at different concentrations (10-100 µg/ml) on the blood coagulation profile, prothrombin time (PT), and activated partial thromboplastin time (a PTT) of apparently healthy human volunteers.
Results: Methanol, ethyl acetate, and n-hexane extracts of F. schweinfurthii aerial parts significantly (p˃0.05) prolonged PT and PTT in the blood of healthy human volunteers with Ethyl acetate and methanol extracts recorded the largest prolongation of PT and PTT correspondingly. The highest PT and PTT prolongation was achieved at 100µg/ml, and the least prolongation time was obtained at 10µg/ml.
Conclusion: These findings displayed that F. schweinfurthii aerial parts contain phytochemical constituents with anticoagulant characteristics and could be used to treat blood clotting disorders.

Peer Review History: 
Received: 26 April 2022; Revised: 12 June; Accepted: 30 June, Available online: 15 July 2022
Academic Editor: Dr. DANIYAN Oluwatoyin Michael, Obafemi Awolowo University, ILE-IFE, Nigeria, [email protected]
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Received file: Reviewer's Comments:
Average Peer review marks at initial stage: 5.5/10
Average Peer review marks at publication stage: 7.0/10
Reviewers:
Dr. Gehan Fawzy Abdel Raoof Kandeel, Pharmacognosy Department, National Research Centre, Dokki, 12622, Giza, Egypt, [email protected] 
Dr. Marwa A. A. Fayed, University of Sadat City, Egypt, [email protected]
Prof. Dr. Hüsniye Kayalar, Ege University, Turkey, [email protected]
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Ischiodon aegyptius
No full text<i>Ischiodon aegyptius</i> (Wiedemann, 1830) <p> <i>Syrphus aegyptius</i> Wiedemann, 1830: 133. Type locality: Egypt & Sudan (Nubia).</p> <p> <i>Musca</i> <i>nigra</i> Forskål, 1775: xxiv. Egypt, Arabia.</p> <p> <i>Syrphus senegalensis</i> Guérin-Méneville, 1832: pl. 99. Type locality: Senegal.</p> <p> <i>Sphaerophoria annulipes</i> (Macquart, 1842): 163. Type locality: " Egypt ".</p> <p> <i>Syrphus longicornis</i> Macquart, 1842: 154. Type locality: South Africa.</p> <p> <i>Syrphus natalensis</i> Macquart, 1846: 262. Type locality: South Africa (Port Natal).</p> <p> <i>Syrphus felix</i> Walker, 1852: 229. Type locality: Canary Is.</p> <p> <i>Sphaerophoria pyrrura</i> Bigot, 1884: 99. Type locality: Senegal.</p> <p> <i>Sphaerophoria borbonica</i> Bigot, 1884: 100. Type locality: Réunion.</p> <p> <i>Syrphus brachypterus</i> (Thomson, 1869): 496. Type locality: Portugal (Madeira).</p> <p> <b>Material examined</b>: 2 females, Kirdassa, 3.IV.2002, leg. El-Hawagry; 1 male, 2 females, Gabel Elba, 15.II– 31.IV.1923, leg. Tewfik, the same specimen that was published in Shaumar & Kamal (1978); 1 male, Ezbet El- Nakhl, 3.IV.1925, leg. Tewfik; 1 male Ghoubbet El-Boos, VIII. 1929, leg. H.C.E. & M.T.; 1 male, Helwan, 12.IX.1925, leg. Farag; 1 female, Wadi Um Elek, 15.10.1928, leg. Farag [EFC].</p> <p> <b>World distribution</b>: AF: Widespread. PA: Balearic Is. Canary Is., Egypt, Iran, Madeira, S. Spain, Syria, Italy.</p> <p> <b>Egyptian localities</b>: Coastal Strip: Alexandria, Cleopatra, El-Dekheila, Mariout. Eastern Desert: Fayed, Ismailiya, Suez Road, Wadies south east of Cairo. Gebel Elba: Wadi Edeib. Lower Nile Valley & Delta: Abu- Rawash, Behaira, Beni Sueif, Cairo, Ezbet El-Nakhl, Faraskour, Gezeirah, Giza, Helwan, Itai El-Baroud, Khanka, Kirdassa, Kombira, El-Mansouriya, Magadla, Pyramids, Shubra, Tisfa, Turah. Sinai: El-Arish, Rafah, Wadi El- Arbaein, Wadi El-Rabba. Upper Nile Valley: Aswan. Western Desert: Kharga Oasis, Siwa Oasis. [Sources: Efflatoun (1922), Shaumar & Kamal (1978) and the examined material collected by the first author].</p> <p> <b>Activity period in Egypt</b>: Throughout the year.</p> <p> <b>Remarks</b>: Adults fly low through sparse ground vegetation and settle on flowers of low-growing herbs (Speight 2017).</p>Published as part of <i>El-Hawagry, Magdi S. & Gilbert, Francis, 2019, Catalogue of the Syrphidae of Egypt (Diptera), pp. 201-248 in Zootaxa 4577 (2)</i> on page 209, DOI: 10.11646/zootaxa.4577.2.1, <a href="http://zenodo.org/record/2629643">http://zenodo.org/record/2629643</a>
