سيجوردور ثورودسن, محمد الجلبي

جامعة الملك عبدالله للعلوم والتقنية · السعودية

A Study on the Violent Interactions of an Immiscible Drop Impacting on a Superheated PoolMohamad AlchalabiThe interactions between two immiscible liquids of different temperatures can be violent to the extent of causing harm to individuals, or damage to equipment, especially when used in the industry. Only a few studies investigated these interactions but they could not produce the violent interactions often reported by the industry, and therefore their results did not help much to develop clear understanding of the dynamics of these interactions. In this work, a high speed imaging system operated at 100,000 frames per second was utilized to record the events and phenomena taking place upon the impact of Perfluorohexane droplet at room temperature onto a hot soybean oil pool at temperatures as high as 300 ºC. The impact velocity was varied by varying the height of the droplet before it pinches off under its own weight. The recorded events identified the occurrence of vortex ring vapor explosions, weak and strong nucleate boiling, and film boiling. An impact velocity vs. oil temperature diagram identifying the regions in which each of these phenomena takes place was generated, and the dynamics driving their occurrences were explored. The vortex ring vapor explosions were found to become less violent as the impact velocity was increased, which was attributed to the existence of a smaller amount of liquid Perfluorohexane within the rings at high speed impacts, which does evaporate but does not expand violently. Weak nucleate boiling occurred at very high impact velocities relatively. As the temperature is increased, however, they start5turning into strong nucleate boiling. The strong nucleate boiling usually starts right upon impact, and when the temperature of the oil at one impact velocity is increased, it starts turning into film boiling, in which the liquid Perfluorohexane is covered by a vapor layer of its own vapor.

Dunya Mohammed Arif, Mohammed Omer Mohammed

كلية الطب-جامعة السليمانية · العراق

أكرم محمود حسين البدو, محمد صديق محمد عبدالله

كلية الحقوق-جامعة الموصل · العراق

Lydia Djaou, Massilia Samah, Nadia Mankou, Z. Sebkhi

كلية العلوم الطبيعية والحياتية-جامعة عبد الرحمان ميرة - بجاية · الجزائر

Les métaux lourds (ETM) sont des éléments chimiques métalliques biopersistants, présentnaturellement dans la nature, ils ont un impact toxique sur la santé humaine, la végétation. Leur présence dansle sol ou l’environnement peut avoir plusieurs origines: naturelles (activité volcanique, incendies), anthropique(apport d’engrais, déchets industriels).Dans la présente étude, on s’est intéressé à l’évaluation des concentrations des métaux lourds (ETM) (Pb, Cd,Zn, Cu) dans le sol et les parties aérienne des différentes cultures dans la zone agricole urbaine de Bejaiacomptant principalement six stations (fermes), s’étendant de TAZMALT à OUED GHIR(INRA) ou a étéprélevés des échantillons du sol, et les cultures végétales pour évaluer le degré de contamination du sol et lesvégétaux en ETM.Dans ce cadre d’activité, on a effectué un dosage par la technique de la spectrophotométrie d’absorptionatomique (SAA) dans le sol et les cultures maraîchères. Les résultats obtenus montrent une corrélation entreles concentrations (teneurs) des ETMs étudiés dans les stations et les teneurs dans les différentes parties descultures végétales (tige, feuille, fruit). Les teneurs de cuivre, plomb, zinc ont été déterminés dans le sol, tige,feuille, fruit. Les résultats montrent que les échantillons ont montrés des teneurs inférieurs aux normes limitesdes stations étudiées. La contamination par le cuivre est très importante au niveau des feuilles, dans la station05: El-kseur. Le Plomb plus élevés dans les sols de la station 06 : INRAA de Bejaia. Le zinc est important auniveau de sol de la station 03 : Ouzellaguen.Cette étude nous a permis de conclure que l’accumulation des éléments traces métalliques dépend del’espace et l’espèce étudier.On peut dire que cette zone est contaminée et qu’il faut trouver des solutions afin de limiter les effetsnéfastes de cette dernière sur l’environnement et sur la santé humaine. Il est préférable de c

Drifa Benkhellat, Siham Benbeka

كلية العلوم الدقيقة-جامعة عبد الرحمان ميرة - بجاية · الجزائر

L’apparition des trous de couverture dans un réseau de capteurs sans fil affecte négativementles performances du réseau, elle a des incidences considérables sur la couverture, la connectivité,les chemins de routage, etc. Par conséquent, la détection de ces trous dès leurs apparitions etprocéder à leurs corrections est une condition sine qua none pour le maintien de la stabilité duréseau et garantir la qualité de service. Dans ce mémoire, nous proposons une nouvelle approchepour détecter les trous de couverture dans les réseaux de capteurs sans l, cette solution sedéroule en trois phases, la première consiste à balayer le réseau avec une droite virtuelle a n detrouver les segments non-couverts, la deuxième s’occupe de la détection éffective des trous decouverture, et en n la troisième, consiste à analyser les trous générés pour fusionner tous lestrous adjacents. La simulation réalisée et l’étude comparative ont montré que notre approcheest très compétitive, puisqu’elle réduit l’erreur moyenne de détection, gagne en précision et entemps d’exécution.

Adnan A. R. Hammud, Munir E. Attiyah

الجامعة الأمريكية في بيروت · لبنان

معروفي يحي, العربي خالد , مالكي توفيق

معهد العلوم القانونية والإدارية-جامعة أحمد بن يحيى الونشريسي - تيسمسيلت · الجزائر

زليخة معلم, نصر الدين مصمودي

كلية العلوم الإنسانية والاجتماعية-جامعة محمد خيضر - بسكرة · الجزائر

Ali Abdel Rahman Saeed Marouf, Zolfa Ayoub Ahmed Aljuzli

كلية الدراسات العليا-جامعة السودان للعلوم والتكنولوجيا · السودان

In this research concentrations of 10 different mineralswere evaluated in commercial whitecheese, pigtail cheese and triangles cheese. Ten minerals were analyzed by an Inductively Coupled plasma-Atomic Emission Spectrometer(ICP-AES). Respective mean mineral concentration (ppm) of white cheese, pigtail cheese and cheese triangles were:Al 94.125,73.75,64.0;Cr 0, 0, 0 ; Mn 1.40,1.2875,0.6875;Fe 13.075,16.45,6.675;Ni 8.6125, 8.8, 6.925; Cu 0, 0, 0 ; Zn 22.4125,22.9125,14.7875;Cd1.2, 0.6625, 0.4375; Ba 0, 0, 0 ;Pb 16.375,4.9,4.6125.These results show that there is some minerals (Cr, Cu and Ba) were not exist and other found with high concentration in comparison with the standard specification.

Mony Trad , Tarek Ghazi Radwan

كلية إدارة الأعمال والاقتصاد-جامعة سيدة اللويزة · لبنان

It is said, any newly implemented system will have some challenges to encounter and tune. In this research study, we did address the students’ experience and satisfaction with the newly implemented hybrid learning system in distressed countries like Lebanon where different challenges are more significant due to the lack of proper IT infrastructure, poor internet connection, and challenging economic conditions. The aim of this study is to determine the level of students’ satisfaction with the implemented hybrid learning system within the Lebanese private sector universities and to explore the key factors that most affect students’ satisfaction with the current hybrid learning model implemented in Lebanon, that is forced by the COVID-19 pandemic and other social and economic challenging conditions. The research process has been done in two steps. The first step covered the most convenient literature review that helped us better understand the key measurable variables affecting students’ satisfaction with the new learning method, then the second step followed was the quantitative approach, where a well-structured questionnaire was prepared and distributed to address the key factors influencing students’ satisfaction from both the social and educational perspectives. Note that,a convenience sampling method was used, where a total of 232 students from five selected universities did participate in the study. This study found that the learning method efficacy, university support, students’ adaptation, and social influence factors do have a significant effect on students’ satisfaction with the implemented hybrid learning system. The learning method efficacy factor did show the highest impacting weight whereas the social influence found to be the least impacting among the 4 identified factors. In addition, no difference in opinion detected among the different gender groups. However, graduate students did show a higher level of satisfaction than under-graduate students. This study did only cover the private sector universities in Lebanon where public sector universities might need to be included in future studies with a wider sample size. In presence of all the challenging conditions that Lebanese students are experiencing due to the bad economic, political, and health conditions, this study will help universities to better identify the main factors that do influence students’ satisfaction with the hybrid learning method so that a proper decisions and actions can be taken to better address the students’ needs while ensuring the required level of learning among Lebanese universities.