2,043 research outputs found

    Analysis of infrared optical polishing effluents and reduction of COD and TSS levels by ultrafiltration and coagulation/flocculation

    Get PDF
    Samples of polishing effluent produced during infrared optics manufacture were analyzed. Their particle size, composition, Zeta potential, chemical oxygen demand (COD), total suspended solids (TSS), and settleable solids were determined. Feasibility of treatment methods such as ultrafiltration (UF) and coagulation/flocculation was investigated to reduce both COD and TSS. It was found that effluents consisted of a suspension of micro- and nanoparticles. Effluent particle size distribution reflected the removal rate of the originating polishing process. Their composition was primarily germanium and other polished substrates as well as polishing abrasives. The effluent Zeta potential was highly negative and prevented particle settling. COD of all specimens was very high, which prevented sewage discharge. Laboratory-scale trials using UF showed substantial COD abatement of up to 74.1%. TSS was reduced to zero after UF. Comparable coagulation/flocculation COD abatement was demonstrated for the highest COD sample

    Metal–Organic Framework Based on Copper and Carboxylate-Imidazole as Robust and Effective Catalyst in the Oxidative Amidation of Carboxylic Acids and Formamides

    Get PDF
    A metal–organic framework (MOF) based on copper and 1,3-bis(carboxymethyl)imidazole (bcmim) was prepared on a gram scale by using a precipitation method at room temperature. The Cu(bcmim)2 MOF was shown to be an efficient catalyst for the preparation of amides through an oxidative coupling between carboxylic acids and formamides in the presence of an oxidant, such as tert-butyl hydroperoxide (TBHP). The method for the preparation of the amides is robust regardless of the carboxylic acid and gives good conversions with good selectivity. The heterogeneous catalyst was recovered unaltered after the reaction, was easily separated from the reaction mixture, and subsequently reactivated by suitable treatment. Moreover, the coupling reaction was scaled up to a gram scale, which allowed for the preparation of valuable products, such as fatty acid amides (i.e., 1-palmitoylpiperidine).The Spanish Ministerio de Economía y Competitividad (CTQ2015-66624-P) and the University of Alicante

    The Temple of Millions of Years of Thutmosis III in Luxor: Preliminary Paleopathological Study and New Perspectives

    Get PDF
    Las excavaciones del Templo de Millones de Años de Thutmosis III (Tebas Oeste) han revelado una gran cantidad de restos humanos (esqueletos y momias) descubiertos en dos ubicaciones principales: tumbas colocadas dentro o junto a las paredes del recinto del templo de inicios del Reino Medio hasta el Período Tardío y las tumbas de una necrópolis del Primer Período Intermedio-Dinastía XI cerca del muro del noreste. El objetivo de este estudio antropológico y paleopatológico ha sido comparar la población a lo largo del tiempo: los individuos del Período Tardío con los del Reino Medio. Se han estudiado un total de 191 individuos (2016-2017): 154 procedentes de las tumbas colocadas dentro del templo y 37 de las tumbas cercanas al muro Nordeste. Las conclusiones preliminares a las que hemos podido llegar tras comparar ambas poblaciones es el mayor porcentaje de marcas de estrés ocupacional en los individuos del Primer Periodo Intermedio − Dinastía XI que en los de Periodo Tardío.The excavation work at the site of the Temple of Millions of Years of Thutmosis III (West Thebes) has revealed a large amount of human remains (skeletons and mummies) uncovered from two main locations: tombs placed within or next to the enclosure walls of the temple dated from the beginning of the Middle Kingdom to the Late Period and graves from a necropolis of the First Intermediate Period – 11th Dynasty close to the north-eastern enclosure wall. The aim of this anthropological and paleopathological study is to compare a population over time: the individuals of the Late Period to those of the Middle Kingdom. A total of 191 individuals have been studied (2016-2017):..154 from the tombs placed inside the wall of the temple and 37 from the tombs close to north-eastern wall. Preliminary conclusions showed a higher percentage of skeletal stress markers in the individuals from the First Intermediate Period – 11th Dynasty, compared with those from the Late Period

    1,3-Bis(3-carboxypropyl)-1H-imidazole

    Get PDF
    The use of γ-aminobutyric acid (GABA) as a starting material in a multicomponent reaction has resulted in the preparation of the zwitterionic 1,3-bis(3-carboxypropyl)imidazole (bcpim). The synthesis of this imidazole derivative in a one-pot procedure with stoichiometric amounts of the corresponding reagents (formaldehyde, glyoxal, and GABA in a 1:1:2 ratio) has resulted in a straightforward and effective methodology, meaning a significant improvement from a sustainable point of view.This research was funded by Ministerio de Ciencia, Innovación y Universidades (grant number PGC2018-096616-B-I00), Ministerio de Ciencia e Innovación (PID2021-127332NB-I00), Generalitat Valenciana (grant number AICO/2021/013), and the University of Alicante (grant number VIGROB-316)

    La Ceramica arabe del Castillo de Orihuela

    Get PDF
    Separata de Archivo Esp. de Arte y Arque. n. 2

    Amino acid-protecting groups

    Get PDF
    Synthetic organic chemistry is based on the concourse of reagents and catalysts to achieve the clean formation of new bonds and appropriate protecting groups are required to prevent the formation of undesired bonds and side-reactions. Thus a promising synthetic strategy can be jeopardized if the corresponding protecting groups are not properly chosen

    1,3-Bis(carboxymethyl)imidazolium Chloride as a Metal-Free and Recyclable Catalyst for the Synthesis of N-Allylanilines by Allylic Substitution of Alcohols

    Get PDF
    The 1,3-bis(carboxymethyl)imidazolium chloride, which is easily and in a straightforward manner prepared readily from starting materials in multigram scale, is employed as catalyst in the synthesis of N-allylanilines by allylic substitution of alcohols with anilines. This metal-free catalyst allows the reaction to be carried out under mild reaction conditions (80 °C and air open vessel) and proved to be efficient for a diversity of anilines and allylic alcohols, providing exclusively the product of N-substitution independently of the substituents in the aniline reactant. The process described is simple and effective, allowing N-allylanilines to be obtained in preparative scale [e.g., 3.30 g of N-(1,3-diphenylallyl)-4-nitroaniline]. The catalyst could be reused up to 15 cycles without loss of activity, proving its robustness.This work was financially supported by the University of Alicante (VIGROB-285) and the Spanish Ministerio de Economía y Competitividad (CTQ2015-66624-P). M.A.S. thanks the Spanish Ministerio de Educación, Cultura y Deporte for a predoctoral fellowship (FPU15/06040)

    Pathological variations in mummified feet between two near-distance/long-time populations in Ancient Egypt

    Get PDF
    Background: In ancient populations, a significant quantity of foot pathology was related either to the type of footwear they used or the underlying terrain they walked on. Our study was carried out to analyze these parameters with the foot pathologies the mummies presented. - Methods: Between 2006 and 2012, more than 650 individuals were recovered from the Sharuna and Qarara necropolis (Middle Egypt) dating from the VIth Dynasty of the first Ptolemaic Period to the second Coptic Period. From among them, a total of 73 mummified feet (41 from Sharuna and 32 from Qarara) were studied. We took into account the differences existing between both sites in location (15 km apart) and in time (2500 years apart). - Results: Almost all feet from Sharuna were wrapped and impregnated with a preservative substance (anthropological mummification), while the mummification process in Qarara was quite natural. Pathologies were found in 36 of the 73 ft (20 from Sharuna and 16 from Qarara). The differences in foot pathologies between the two sites were analysed. - Conclusions: The foot pathologies we found in both necropolises have led us to hypothesise that the majority of the diachronic differences could be related more to progressive changes in the type of the terrain brought out through droughts, than the changes in footwear habits
    corecore