65 research outputs found
The multiple subject construction in Arabic : evidence from subject doubling in Tunisian Arabic
Phd ThesisThis dissertation explores the syntax of set of subject constructions in Tunisian Arabic (TA) comprising a NP and a third person free-standing pronoun, known in the literature of Arabic grammar as an H-Form (Fassi Fehri 1993). The subject NP-H pair has three main realisations, each of which will be shown to have a distinct information structure: an NP-H sequence, where the NP is doubled by the H-form, conveying contrastive topic, an H-NP sequence, where the NP is again doubled by the H-form, expressing a thetic meaning, and an NP-H sequence conveying contrastive/exhaustive focus where the H-form is a nominal copula of a cleft construction. The two subject doubling sequences are analysed as realisations of the same syntactic structure, a multiple subject construction (MSC), but for the values of the syntactic information-structural features [Top(ic)] and [Foc(us)]. The NP-H sequence has the NP in the spec(ifier) of a Top head and the H-form in the spec of the head Fin(ite), specified for Focus. The combination of [+Top] and [+Foc] yields the contrastive topic reading. The H-NP sequence has the H in the spec of Top and the NP in the spec of Fin. The combination of the expletive H in spec of Top and the focused NP in spec of Fin yields the thetic reading. The parameter distinguishing between languages with subject doubling of the TA type and languages without, as English, is about the specification of Fin. In English Fin has an EPP feature attracting any subject, topic or focus or expletive. In TA, Fin is specified for [Foc EPP] only. Topic-marked subjects are attracted by a higher Top head, marked for [Top, EPP], where the latter can be satisfied by an expletive in the absence of a topical subject. It will be shown that Finnish and Icelandic have the same parameter specification as TA, therefore exhibiting a MSC with properties similar to the MSC in TA. The NP-H pair is base-generated as a Small Clause embedded in a so called âbig DPâ, where the NP is the subject and the H-pronoun the predicate. There is only partial agreement between the two terms; in particular there is no person agreement. The MSC is derived by separate movement of the NP and the H-pronoun
Clay/Conductive Polymer Nanocomposites
This chapter describes the main strategies for designing clay nanocomposites of the most investigated inherently conductive polymers, namely, polypyrrole, polyaniline, and polythiophenes including poly(3,4-ethylenedioxythiophene) polystyrene sulfonate. It is shown that premodification of clays is an essential step to successful intercalation or exfoliation by conductive polymers. Toward this end, surfactants, reactive diazonium, and silanes permit the preparation of adhesive clay sheets for the conductive polymers once polymerization is triggered. Exfoliated nanocomposites usually exhibit superior properties compared to intercalated ones. Through selected applications (e.g., conductive fillers, catalysts, sensors, ultracapacitors), it is clear that research on clayâconductive polymer nanocomposites will continue to grow because these materials combine the best of two worlds: low-cost abundant minerals with remarkable nanostructural properties and nanostructuring abilities on the one hand and ease of synthesis, reactivity, and electrical conductivity of conjugated polymers on the other hand.Scopu
Analyse ergonomique semi-quantitative des contraintes biomécaniques du rachis cervical parmi les opérateurs sur écran dans les établissements universitaires tunisiens
Introduction: évaluer les contraintes biomécaniques associées aux cervicalgies parmi les opérateurs sur écran.
MĂ©thodes: Ă©tude ergonomique rĂ©alisĂ©e au prĂ©s de 325 opĂ©rateurs sur Ă©cran dans 25 Ă©tablissements de lâuniversitĂ© du centre tunisien, basĂ©e sur une Ă©tude anthropomĂ©trique du poste du travail sur Ă©cran et une analyse semi-quantitative sur des enregistrements vidĂ©o des activitĂ©s des travailleurs conduits sur une pĂ©riode reprĂ©sentative de 30 minutes.
RĂ©sultats: la prĂ©valence des cervicalgies Ă©valuĂ©e Ă 72,3%, a concernĂ© une population de travailleurs qui exerçait avec un siĂšge et un plan de travail inadaptĂ©s (84,6%) et un Ă©cran bas situĂ© par rapport au regard horizontal (81,2%). Lâanalyse semi-quantitative par enregistrement vidĂ©o du poste de travail a conclu que la nuque Ă©tait maintenue en flexion franche de plus de 40 degrĂ©s sur 69% du temps global du travail. La flexion latĂ©rale a Ă©tĂ© visible sur 50,3% du temps de travail et la rotation droite ou gauche sur 57,4% du temps de travail. Ainsi, Les opĂ©rations de prise dâinformation de lâĂ©cran, de regard du clavier et de consultation des documents se sont dĂ©gagĂ©es comme les plus de contraignantes pour la nuque sur le plan gestuel et postural.
Conclusion: nos rĂ©sultats mettent en Ă©vidence lâimportance des contraintes biomĂ©caniques associĂ©es Ă la conception du poste de travail sur Ă©cran non conforme aux dimensions anthropomĂ©triques ergonomiquement recommandĂ©es. Ces contraintes sont associĂ©es Ă une prĂ©valence Ă©levĂ©e des cervicalgies traduisant la nĂ©cessitĂ© dâamĂ©nagement ergonomique de ces postes de travail pour prĂ©venir ce flĂ©au
Data on the fabrication of hybrid calix [4]arene-modified natural bentonite clay for efficient selective removal of toxic metals from wastewater at room temperature
Fresh water resources on the earth are less than 0.2%; meanwhile, around 80% of the freshwater is consumed daily in agriculture, industries, and household activities [1â2]. There is an essential need to develop efficient adsorbents for wastewater treatment [1â6], in this regards, hereafter we present the rationale synthesis and characterization of hybrid natural bentonite clay modified with Calix [4] arene (denoted as B-S-Calix) as efficient adsorbents for toxic metals from wastewater. This is driven by the facile photo-radical thiol-yne addition among the thiolated clay and an alkynylated calix[4]arene. The morphology, surface modifications, and Thermal degradation of B, B-S, and B-S-Calix were investigated using TEM, FTIR, and TGA techniques. The adsorption performance of B, BS and B-S-Calix towards toxic metals including cadmium (II) ion [Cd (II)], zinc (II) ion [Zn(II)], lead(II) ion [Pb(II)], strontium(II) ion [Sr (II)], cobalt(II) ion [Co (II)], copper(II) ion [Cu(II)], and mercury (II) ion [Hg(II)] from wastewater were benchmarked 25 °C. These data are related to the article entitled âhybrid Clay/Calix[4]arene Calix[4]arene-clicked clay through thiol-yne addition for the molecular recognition and removal of Cd(II) from wastewaterââ [7]
Rational synthesis, characterization, and application of environmentally friendly (polymerâcarbon dot) hybrid composite film for fast and efficient UV-assisted Cd<sup>2+</sup> removal from water
Background: Carbon dots (CDs) are of particular interest in numerous applications. However, their efficiency for heavy metal removal from wastewater was not yet reported. Herein, we rationally synthesized CDs from petroleum coke waste via hydrothermal treatment in the presence of ammonia. Results: This drove the formation of outstanding photoluminescent, water-soluble, biocompatible, and high yield of monodispersed sub-5 nm CDs. The CDs are co-doped with high 10% of N and 0.2% of S. The as-prepared CDs possess unprecedented photoluminescent properties over broad pH range making these dots unique efficient pH sensor. Conclusions: Chitosan (CH)âCDs hybrid hydrogel nanocomposite film was further prepared as a platform membrane for the removal Cd2+ metal from wastewater. The as-prepared CHâCDs membranes show relatively good mechanical properties, based on stress resistance and flexibility to facilitate handling. The equilibrium state was reached within 5 min. Intriguingly, the UV-light illuminations enhanced the Cd2+ removal efficiency of the photoluminescent CDs substantially by four times faster under. It was found that adsorption followed pseudo-second-order kinetic and Langmuir isotherm models. The maximum adsorption capacity at 25 °C was found to be 112.4 mg gâ1 at pH 8. This work paves the way to new applications of CDs in water treatment.[Figure not available: see fulltext.]
Anti-corrosive and oil sensitive coatings based on epoxy/polyaniline/magnetite-clay composites through diazonium interfacial chemistry
Epoxy polymer nanocomposites filled with magnetite (Fe3O4) clay (B), named (B-DPA-PANI@Fe3O4) have been prepared at different filler loading (0.1, 0.5, 1, 3, 5 wt. %). The surface modification of clay by polyaniline (PANI) is achieved in the presence of 4-diphenylamine diazonium salt (DPA). The effects of the nanofiller loading on Tensile, mechanical and dielectric properties were systematically studied. Improved properties was highlighted for all reinforced samples. The addition of only 3 wt. % of the filler enhanced the tensile strength of the composites by 256%, and the glass transition temperature Tg by 37%. The dielectric spectra over a broad frequency showed a robust interface between the hybrid (B-DPA-PANI@Fe3O4) fillers and epoxy matrix. The results showed most significant improvement in corrosion inhibition using electrochemical impedance spectroscopy (EIS) in 3.5 wt % NaCl, as well as a significant response in oil sensing test. High charge transfer resistance of 110 à 106 Ω.cm2 using 3-wt % of filler was noted compared to 0.35 à 106 Ω.cm2 for the pure epoxy. The results obtained herein will open new routes for the preparation of efficient anticorrosion sensor coatings. © 2018, The Author(s).NPRP Award from the Qatar National Research Fund (a member of Qatar Foundation) [8-878-1-172
Modulation of Sn concentration in ZnO nanorod array: intensification on the conductivity and humidity sensing properties
Tin (Sn)-doped zinc oxide (ZnO) nanorod arrays (TZO) were synthesized onto aluminum-doped ZnO-coated glass substrate via a facile sonicated solâgel immersion method for humidity sensor applications. These nanorod arrays were grown at different Sn concentrations ranging from 0.6 to 3 at.%. X-ray diffraction patterns showed that the deposited TZO arrays exhibited a wurtzite structure. The stress/strain condition of the ZnO film metamorphosed from tensile strain/compressive stress to compressive strain/tensile stress when the Sn concentrations increased. Results indicated that 1 at.% Sn doping of TZO, which has the lowest tensile stress of 0.14 GPa, generated the highest conductivity of 1.31 S cmâ 1. In addition, 1 at.% Sn doping of TZO possessed superior sensitivity to a humidity of 3.36. These results revealed that the optimum performance of a humidity-sensing device can be obtained mainly by controlling the amount of extrinsic element in a ZnO film
Chapter 1 - Overview: Clay Preparation, Properties, Modification
This chapter reviews clay physicochemical properties and general methods of modification with a view to making a clayâpolymer nanocomposite. The first part includes an overview of clays, their different structures, and their physicochemical properties. The second part concerns a literature survey of the most applied methods of organic modification of clays. New trends are also highlighted.This chapter was made possible by NPRP award [8-878-1-172] from the Qatar National Research Fund (a member of the Qatar Foundation). The statements made herein are solely the responsibility of the authors
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