Optical and interferometric studies on oscillating quartz crystals

The methods of investigation in the present work deal with: firstly the calculation of the frequencies of vibration of the different modes of extensional vibrations both radial and torsional of circular, solid and annular, plates as predicted by Love's theory. These are experimentally examined and empirical rules governing the frequencies are evolved. Secondly, the physical form of the vibration at the different calculated resonant frequencies is observed. This is carried out either by investigating the position of the nodal and antinodal regions on the vibrating surface or by investigating the distribution of stress inside the body of the vibrator. Three methods of observations have been used, namely, the interference method and this gives a measurement of displacements in the normal direction to the plate surface, together with an exact measurement of the surface amplitudes of the vibrating plate. Chapter IX is dealing with amplitude measurements. The powder method and it will be shown that it gives indication of both vertical and horizontal displacements. The third method used for the present investigation gives the stress distribution within the specimen provided the specimen is sufficiently thin. It is shown that it is generally unreasonable to expect any one method of observation to give a reliable solution to the type of motion and to the mode of vibrating body. The three methods together should be used in order to give a sound information about the vibrating motion; otherwise a misleading representation of the state of vibration is likely to arise.A practical agreement has been found between the theoretical and observed patterns for the second and third methods of investigation. The interference method did not offer a good correlation between theoretical and observed patterns; since it is always coupled to flexural modes of particular symmetry. However, the method gives an exact measurement of the surface amplitudes. The measurements require no calibration.<p

Continental Arc Plutonism in a Juvenile Crust: The Neoproterozoic Metagabbro-Diorite Complexes of Sinai, Northern Arabian-Nubian Shield

Based on new field, petrographic, and whole-rock geochemistry data, we investigated three discrete metagabbro-diorite complexes (MGDC) across the E-W Sinai to contribute to increasing knowledge of the evolution of the juvenile continental crust of the Neoproterozoic Arabian–Nubian Shield. The three MGDCs vary in the dominance of the gabbroic versus dioritic rock types among each of them. Gabbroids are distinguished into pyroxene-hornblende gabbros and hornblende gabbros, whereas dioritic rocks have been subdivided into diorites and quartz diorites. The studied MGDC rocks are almost metaluminous and possess prevalent calc-alkaline characteristics over subsidiary tholeiitic and alkaline affinities. The most distinctive feature in the profiles of the investigated MGDCs on the N-MORB-normalized spider diagrams is the coincidence of stout negative Nb anomalies and projecting positive Pb spikes, which is typical of igneous rocks evolved in subduction zones. The three MGDC samples exhibit variably LREE-enriched patterns [(La/Yb)N = 4.92–18.55; av. = 9.04], either lacking or possessing weak to negligible positive and negative Eu anomalies. The calculated apatite and zircon crystallization temperatures reveal the earlier separation of apatite at higher temperatures, with the obvious possibility of two genetic types of apatite and zircon in the magma (cognate vs. xenocrystic) since both accessories have yielded very wide ranges of crystallization temperatures. The investigated MGDCs were formed in a continental arc setting, particularly a thick-crust arc (>39 km). The parent magmas comprised components derived from the melting of the mantle wedge, subducting oceanic lithosphere, and subducting overlying sediments. The mantle input was from a spinel–garnet transitional mantle source at a depth of ca. 75–90 km. The impact of slab-derived fluids was much greater than that of slab-derived melts, and so subduction-related fluids had a crucial effect on metasomatizing the partially melted mantle source. The parent mantle-derived magma has been subjected to substantial crustal contamination as a dominant mechanism of differentiation

Les reines et princesses de la XVIIIe dynastie à Thèbes-Ouest (enquête d'après les monuments, les sources archéologiques et épigraphiques)

Nous présentons dans cette thèse une analyse de la documentation des reines et princesses de la XVIIIème dynastie rassemblée à partir d'une enquête menée sur l'ensemble des tombes thébaines, royales et de particuliers. Ces données rassemblées, année après année, à l'occasion de visites répétées, d'ouverture de chantiers de conservation sur tous les secteurs de la nécropole, ont fait ressortir que l'information, très abondante pourtant, rassemblée depuis le XIXème siècle, sur le rôle joué par les membres féminins de la famille des pharaons de la XVIIIème dynastie demeurait très incomplète. Parmi les lacunes les plus importantes figurait l'absence de relevés ou de collationnement moderne de très nombreuses scènes et inscriptions peintes ou gravées sur les parois des chapelles des serviteurs royaux en fonction aux temps où reines et princesses avaient vécu. Le répertoire de sources établi et présenté à l'appui de ce travail constitue, pour l'immédiat, l'état le plus fidèle d'une documentation souvent en péril, fréquemment en voie de destruction. Dans ce cadre, les sources archéologiques et épigraphiques concordent pour témoigner d'un fait apparemment sans précédent : le rôle de la famille royale et, en particulier, des "grandes épouses royales" dans les affaires politiques et religieuses. En effet, à la cour, leur position est loin de se limiter à des tâches purement protocolaires. Visiblement les reines de la XVIIIème dynastie détiennent un pouvoir réel et deviennent, en quelque sorte, des partenaires à part entière aux côtés du pharaon régnant. Non seulement celles-ci s'intéressent aux rouages de l'Etat, interviennent dans la diplomatie, mais encore elles occupent souvent d'importantes fonctions religieuses. Qu'il s'agisse d'Ahmes Nefertari, l'épouse d'Ahmosis et mère d'Aménophis Ier, d'Hatshepsout, la "reine pharaon", de Tiy, la grande épouse royale d'Aménophis III, ou encore de Nefertiti, la conjointe officielle d'Aménophis IV - Akhenaton qui ne ménage aucun effort pour que se concrétise la "rénovation" atonienne, toutes ces reines et bien d'autres occupent un rang des plus élevés dans la hiérarchie du royaume et y jouissent d'une influence unique dans le monde antique et son histoire. Aux côtés des reines et de leurs époux une place non négligeable a été réservée ici aux filles de sang princier. En essayant de faire le point sur les familles royales de la XVIIIème dynastie à partir de la documentation issue du décor et des textes des chapelles des tombes thébaines du Nouvel Empire, il devenait indispensable de réunir l'ensemble des sources officielles originaires de la même région afin d'en confronter les données. De même, il convenait de faire appel à tous les autres témoins connus en terre d'Egypte ou en Nubie et à l'extérieur, afin de constituer pour chaque reine ou princesse prise en compte un dossier personnel auquel leur viendraient s'adjoindre les attestations thébaines spécifiques rassemblées lors du recensement systématique effectué sur le terrain. Les cinquantes entrées établies de la reine Ahhotep (I) à sa lointaine consoeur Moutnedjemet, épouse d'Horemheb, constituent le répertoire historique, lequel est suivi de la discussion et de la conclusion (Volume I, 253 pages). Dans le second volume de l'ouvrage (168 pages), le répertoire iconographique et épigraphique est présenté sous forme de 134 fiches et 74 planches (catalogue).LYON2/BRON-BU (690292101) / SudocSudocFranceF

Powtórny zabieg przezskórnej walwuloplastyki mitralnej u chorych z nawrotem zwężenia zastawki - porównanie z pierwszorazowym zabiegiem u osób ze zwężeniem de novo

Background: Percutaneous mitral valvuloplasty (PMV) has emerged as the procedure of choice in most patients with symptomatic mitral stenosis. However, very few reports have looked at redo PMV in patients with mitral restenosis. Aim: In a retrospective study, we explored the immediate results of redo PMV compared to primary PMV. Methods: We included 30 consecutive patients with de novo mitral stenosis and 40 consecutive patients with mitral restenosis after successful initial PMV. Echocardiographic assessment of the mitral valve was performed in all patients by transthoracic echocardiography (TTE), and trans-esophageal echocardiography excluded left atrial thrombosis. Percutaneous mitral valvuloplasty was performed by the antegrade trans-septal approach using either the standard Inoue technique or the multitrack technique. Patient assessment by TTE was repeated 48 hours after the procedure. Procedural success was defined as a 50% or more increase in mitral valve area, with a final mitral valve area &#8805; 1.5 cm2, without major complications. Results: The mean age of the study population was 33.7 &#177; 6 years, 18 (25.7%) patients being male. Procedural success was achieved in 28 (93.3%) patients undergoing first PMV, and in 37 (92.5%) patients undergoing redo PMV (NS). The two groups were similar in terms of the final mitral valve area, the gain of mitral valve area, the mean pressure gradient across the mitral valve, and the complication rate (NS for all). The final mitral valve area correlated negatively with the baseline mitral valve score in both groups. Conclusions: Redo PMV for mitral restenosis achieves immediate results that are comparable to initial PMV for de novo mitral stenosis. Kardiol Pol 2011; 69, 2: 125-131Wstęp: Przezskórna walwuloplastyka mitralna jest obecnie leczeniem z wyboru u większości chorych z objawowym zwężeniem zastawki mitralnej. Jednak opublikowano niewiele prac dotyczących powtórnych zabiegów walwuloplastyki u chorych z nawrotem zwężenia zastawki. Cel: W badaniu retrospektywnym oceniano bezpośrednie wyniki powtórnych zabiegów walwuloplastyki mitralnej w porównaniu z wynikami procedur pierwszorazowych. Metody: Do badania włączono 30 chorych ze zwężeniem de novo zastawki mitralnej (grupa A) oraz 40 kolejnych pacjentów z nawrotem zwężenia po wcześniejszej skutecznej walwuloplastyce przezskórnej (grupa B). Ocenę echokardiograficzną przeprowadzono za pomocą badania przezklatkowego, a badanie przezprzełykowe miało na celu wykluczenie skrzepliny w lewym przedsionku. Przezskórną walwuloplastykę mitralną wykonywano poprzez nakłucie przegrody międzyprzedsionkowej z zastosowaniem standardowej techniki Inoue&#8217;go lub techniki multi-track. Po 48 godzinach od zabiegu powtarzano badanie przezklatkowe. Procedurę definiowano jako skuteczną, gdy zwiększenie pola powierzchni zastawki po zabiegu wynosiło &#8805; 50%, a ostateczna wartość pola powierzchni była większa lub równa 1,5 cm2, bez poważnych powikłań. Wyniki: Średni wiek pacjentów włączonych do badania wynosił 33,7 &#177; 6 lat, 25,7% (18 osób) stanowili mężczyźni. Zabieg zakończył się powodzeniem u 28 (93,3%) pacjentów w grupie A i u 37 (92,5%) chorych w grupie B (p = NS). W obu grupach powierzchnia zastawki po zabiegu, przyrost powierzchni, średni gradient przez zastawkę i częstość powikłań były podobne. (p = NS dla wszystkich). Powierzchnia zastawki po zabiegu ujemnie korelowała z punktacją zastawki przed zabiegiem w obu grupach. Wnioski: Bezpośrednie wyniki powtórnego zabiegu przezskórnej walwuloplastyki mitralnej u chorych z nawrotem stenozy mitralnej są porównywalne z wynikami walwuloplastyki mitralnej wykonywanej z powodu zmian de novo. Kardiol Pol 2011; 69, 2: 125-13

Quenching of quorum sensing in multi-drug resistant Pseudomonas aeruginosa: insights on halo-bacterial metabolites and gamma irradiation as channels inhibitors

Abstract Background Anti-virulence therapy is a promising strategy to treat multi-drug resistant (MDR) pathogens. Pseudomonas aeruginosa is a potent opportunistic pathogen because of an array of virulence factors that are regulated by quorum sensing systems. Methods The virulence features of four multi-drug resistant P. aeruginosa strains were investigated upon exposure to the sub-lethal dose of gamma rays (1 kGy), and sub-inhibitory concentrations of bioactive metabolites recovered from local halophilic strains in comparison to control. Then, the gene expression of AHL-mediated quorum sensing systems (las/rhl) was quantitatively determined in treated and untreated groups by real-time PCR. Results The bioactive metabolites recovered from halophilic strains previously isolated from saline ecosystems were identified as Halomonas cupida (Halo-Rt1), H. elongate (Halo-Rt2), Vigibacillus natechei (Halo-Rt3), Sediminibacillus terrae (Halo-Rt4) and H. almeriensis (Halo-Rt5). Results revealed that both gamma irradiation and bioactive metabolites significantly reduced the virulence factors of the tested MDR strains. The bioactive metabolites showed a maximum efficiency for inhibiting biofilm formation and rhamnolipids production whereas the gamma irradiation succeeded in decreasing other virulence factors to lower levels in comparison to control. Quantitative-PCR results showed that AHL-mediated quorum sensing systems (las/rhl) in P. aeruginosa strains were downregulated either by halo-bacterial metabolites or gamma irradiation in all treatments except the upregulation of both lasI internal gene and rhlR intact gene in P. aeruginosa NCR-RT3 and both rhlI internal gene and rhlR intact gene in P. aeruginosa U3 by nearly two folds or more upon exposure to gamma irradiation. The most potent result was observed in the expression of lasI internal gene that was downregulated by more than ninety folds in P. aeruginosa NCR-RT2 after treatment with metabolites of S. terrae (Halo-Rt4). Analyzing metabolites recovered from H. cupida (Halo-Rt1) and H. elongate (Halo-Rt2) using LC–ESI–MS/MS revealed many chemical compounds that have quorum quenching properties including glabrol, 5,8-dimethoxyquinoline-2-carbaldehyde, linoleoyl ethanolamide, agelasine, penigequinolones derivatives, berberine, tetracosanoic acid, and liquidambaric lactone in the former halophile and phloretin, lycoctonine, fucoxanthin, and crassicauline A in the latter one. Conclusion QS inhibitors can significantly reduce the pathogenicity of MDR P. aeruginosa strains; and thus can be an effective and successful strategy for treating antibiotic resistant traits

Numerical and wind tunnel investigation of Hot Air Recirculation across Liquefied Natural Gas Air Cooled Heat Exchangers

Air Cooled Heat Exchangers (ACHE)s are used for heat rejection in Liquefied Natural Gas (LNG) plants. Their thermal performance decreases under elevated ambient temperatures and windy conditions as exhaust air recirculates back into the ACHE units causing Hot Air Recirculation (HAR). This paper investigates the effect of various incident wind speed and directions on HAR. Understanding HAR helps to avoid undesirable work conditions. Three dimensional Computational Fluid Dynamics (CFD) studies were utilized to simulate the airflow around a full scale LNG plant. The simulations clearly captured HAR between parallel ACHE banks (Cross-HAR) and within a single ACHE unit (Self-HAR). Wind tunnel smoke visualization was used to qualitatively assess the CFD model. The impact of removing downstream ACHE protection screens on the HAR was computationally investigated showing an exhaust air temperature reduction of 5�C. Different HAR mitigation methods were proposed using different configurations of side winglets. Horizontal winglets were shown to be more effective than vertical winglets as they decreased intake and exhaust air temperatures by about 5�C and 8�C respectively and increased exhaust air velocity by 1.2 m/s. This work provides a thorough understanding of HAR around ACHEs and proposes mitigation methods to reduce its effects on plant production. - 2017 Elsevier LtdScopu

Design challenges of agricultural greenhouses in hot and arid environments - A review

Protected Agriculture (PA) presents a sustainable solution for food production in hot and arid environments. Harsh climate and the water deficit are obstacles to all year round cultivation. The greenhouse design should provide adequate control of its microclimate, such as temperature, relative humidity, CO2 concentration, and lightning depending on ambient conditions and the type of cultivation. This paper provides a thorough review of previous research on greenhouses design features, deemed important for efficient operation in hot and arid environments, such as dimensions, orientation, shapes, covering and shading materials. Effective greenhouse cooling methodologies and operation strategies to achieve and maintain satisfactory climate conditions in hot and arid conditions are investigated. Namely, natural and forced ventilation, evaporative cooling and fogging systems. Furthermore, the paper discusses the greenhouse control methods (field, remote, direct and combined) to monitor and regulate the indoor climatic parameters. Finally, the paper focuses on current greenhouse sustainable technologies and clean energy applications that contribute towards minimizing dependency on fossil fuels and leading to efficient water management. Namely, storage systems, humidification/dehumidification systems and Photovoltaic Panels. The future challenges facing the protected agriculture sector are identified. Suggestions of future scientific research and development topics are proposed.Scopu