The aim of the present research is to study the dissolution and transport process of
benzene as a light nonaqueous phase liquid (LNAPL) in saturated porous media.
Unidirectional flow at water velocities ranged from 0.90 to 3.60 cm/hr was adopted to study
this process in a three dimensional saturated sand tank (100 cm×40 cm×35 cm). This tank
represents a laboratory-scale aquifer. The aquifer was constructed by packing homogeneous
sand in the rectangular tank. The experimental results were used to characterize the
dissolution behavior of an entrapped nonaqueous phase benzene source in a three dimensional
aquifer model. The time invariant average mass transfer coefficient was determined at each
interstitial velocity, the values of this coefficient were ranged from 0.016 to 0.061 cm/hr. It
was increased proportionally with velocity toward a limiting value. The results show that the
concentration of the LNAPL reduces as the distance increased in x and/or z direction from the
source of pollution. In most cases the benzene concentration declines with velocity more than
2.34 cm/hr at downstream of the LNAPL pool.
Vapor-liquid equilibrium data are presented for the binary systems n-hexane - 1-propanol, benzene - 1-propanol and n-hexane – benzene at 760 mm of mercury pressure. In addition ternary data are presented at selected compositions with respect to the 1-propanol in the 1-propanol, benzene, n-hexane system at 760 mmHg. The results indicate the relative volatility of n-hexane relative to benzene increases appreciably with addition of 1-propanol.
Nimodipine (NMD) is a dihydropyridine calcium channel blocker useful for the prevention and treatment of delayed ischemic effects. It belongs to class ? drugs, which is characterized by low solubility and high permeability. This research aimed to prepare Nimodipine nanoparticles (NMD NPs) for the enhancement of solubility and dissolution rate. The formulation of nanoparticles was done by the solvent anti-solvent technique using either magnetic stirrer or bath sonicator for maintaining the motion of the antisolvent phase. Five different stabilizers were used to prepare NMD NPs( TPGS, Soluplus®, HPMC E5, PVP K90, and poloxamer 407). The selected formula F2, in which Soluplus
has been utilized as a stabilizer, has a par
... Show MoreThe aim of this scientific study is to diagnose the nature of the relationship between academic education in the field of media, communication and media practice. The university offers theoretical and practical lessons to students on the concepts of communication sciences, theories, models, legislations, ethics, and techniques over three years or more. And the diploma in the field of communication and Media Sciences gives students the opportunity to work in the field of journalism and media in the future, this is what many academics and media thinkers in Algeria believe, while another trend sees the exact opposite: The study of information and communication sciences within the university in the form of theoretical lessons cannot contribu
... Show MoreAbstract The dissemination of knowledge is no longer confined to schools and universities, not even books. For nearly two centuries, the media have become prominent in disseminating knowledge and culture, in its public and particularly political aspects. After the development of the media from newspapers and magazines to the visual media, their role has increased from the dissemination of abstract information and abstract knowledge towards the process of forming new knowledge through what it publishes and broadcasts from different programs such as drama, news and talk shows. The impact of the media has changed the overall community awareness. Half a century ago the media was not so powerful and widespread. The evolution of the 1990s made
... Show Moreكانت وسائل الاعلام- التقليدية والحديثة – وستبقى وسيلة مهمة لتدفق المعلومات والتعبير عن المشاعر ووصف الاحداث وتشكيل الرأي العام المحلي والدولي عن مختلف القضايا التي تهم الافراد والمجتمعات وفي مقدمتها قضايا العنف بمستوياته كافة ،والتطرف الديني والارهاب بكل مسمياته وستحاول هذه الدراسة ان تقدم اجابات عن اسئلة محددة تمثل الاطار النظري لدراسات مسحية ترصد النظريات التي ترسم الاطر النظرية الت
... Show MoreThe study aimed to reveal the degree of inclusion of media concepts in the books of social and national studies in general education in light of the criteria of media education and the nature of the Saudi society. Additionally, to identify the estimations of the participants in the study of the importance of including media concepts in these books, and to build a matrix of the range and sequence of media concepts in the books of social and national studies in the grades of Saudi general education. The study followed the descriptive approach in both descriptive analysis of the textbooks and descriptive survey of the study participants who were (203) students in the schools of boys and girls in general education in Makkah. The study used t
... Show Moreto evaluate the effect of various Nd:YAG frequency doubled laser parameters on the acid
dissolution and the progression of in vitro caries like lesions in human enamel.
Materials and Methods: Human extracted caries free upper first premolar teeth were collected for
this study. The irradiated teeth were divided into two groups. The first group was irradiated with
continuous Nd:YAG laser radiation, and the second group was irradiated with chopped Nd:YAG laser
radiation. For the first group, power and exposure time were changed while for the second group
power and number of pulses were changed. The spot diameter was kept constant for all the samples.
Results: using 1.5 W and 3 seconds (exposure time), best results among
Cadmium sulfide photodetector was fabricated. The CdS nano
powder has been prepared by a chemical method and deposited as a
thin film on both silicon and porous p- type silicon substrates by spin
coating technique. Structural, morphological, optical and electrical
properties of the prepared CdS nano powder are studied. The X-ray
analysis shows that the obtained powder is CdS with predominantly
hexagonal phase. The Hall measurements show that the nano powder
is n-type with carrier concentration of about (-5.4×1010) cm-3. The
response time of fabricated detector was measured by illuminating
the sample with visible radiation and its value was 5.25 msec. The
specific detectivity of the fabricated det
In this work gold nanoparticles (AuNPs), were prepared. Chemical method (Seed-Growth) was used to prepare it, then doping AuNPs with porous silicon (PS), used silicon wafer p-type to produce (PS) the processes doping achieved by electrochemical etching, the solution etching consist of HF, ethanol and AuNPs suspension, the result UV-visible absorption for AuNPs suspension showed the single peak located at ~(530 – 521) nm that related to SPR, the single peak is confirmed that the NPs present in the suspension is spherical shape and non-aggregated. X-ray diffraction analysis indicated growth AuNPs with PS. compare the PS layer without AuNPs and with AuNPs doped for electrical properties and sensitivity properties we found AuNPs:PS is more
... Show MoreThe present work shows a theoretical results that have been used the functional Hybrid of three parameters Lee-Yang-Parr (B3LYP) of the quantum mechanical approach for density functional theory with (Spanish Initiative for Electronic Simulations with Thousands of Atoms) SIESTA code. All calculations were carried out employing the used method at the Gaussian 09 package of programs. It was reported the main point for research on dominance of the bandgap of elongated pi-conjugated molecules by using different chemical groups replacing hydrogen atom in the most molecules that used in this work. The side groups creates another factor that controls the value of the band gap. The dihedral angle between the two pheny
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