455 research outputs found

    Amination of 2-Bromo-6-Methylaminopyridine

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    Extended metal atom chains (EMACs) represent molecular structures comprising a linear arrangement of metal ions, accompanied by supporting ligands. These compounds possess intriguing properties, yet remain understudied, drawing interest from diverse fields such as physics. However, synthesizing these multimetallic complexes poses significant challenges due to their intricate nature and specificity. Bridging ligands like silyl aminopyridine (SAP) and dipyridyl amine (DAP) have been utilized successfully to support EMACs, with SAP\u27s application in this context being limited to a single published case, highlighting the urgent need for stabilization. This project aims to address this challenge through the synthesis of a novel scaffolded ligand, facilitating the creation of more robust EMACs. The synthesis process entails a meticulous three-step procedure, offering promising prospects for advancing the understanding and application of EMACs in various scientific domains

    ELABORAÇÃO DE UM SITE PARA A SECRETARIA DE TURISMO DE BRUSQUE

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    A construção de um site, como instrumento de ensino-aprendizagem naprogramação e atividade de extensão é o foco do presente trabalho. Graças aoconhecimento obtido, pretende-se investir com retorno de valor em ensino, tantodidático por parte do discente, como social, por parte do produto final quedisponibilizamos. A metodologia versa sobre preceitos de turismo aliados aos deprogramação, web-design e banco de dados e, assim, para obter-se o resultadoesperado, são estipuladas metas e realizadas avaliações de websites com atemática em lide, bem como levantamentos para a abordagem detalhada, visandoestabelecermos aspectos positivos e negativos da proposta

    Modeling of Aerosol Vertical Profiles Using GIS and Remote Sensing

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    The use of Geographic Information Systems (GIS) and Remote Sensing (RS) by climatologists, environmentalists and urban planners for three dimensional modeling and visualization of the landscape is well established. However no previous study has implemented these techniques for 3D modeling of atmospheric aerosols because air quality data is traditionally measured at ground points, or from satellite images, with no vertical dimension. This study presents a prototype for modeling and visualizing aerosol vertical profiles over a 3D urban landscape in Hong Kong. The method uses a newly developed technique for the derivation of aerosol vertical profiles from AERONET sunphotometer measurements and surface visibility data, and links these to a 3D urban model. This permits automated modeling and visualization of aerosol concentrations at different atmospheric levels over the urban landscape in near-real time. Since the GIS platform permits presentation of the aerosol vertical distribution in 3D, it can be related to the built environment of the city. Examples are given of the applications of the model, including diagnosis of the relative contribution of vehicle emissions to pollution levels in the city, based on increased near-surface concentrations around weekday rush-hour times. The ability to model changes in air quality and visibility from ground level to the top of tall buildings is also demonstrated, and this has implications for energy use and environmental policies for the tall mega-cities of the future

    The First Detections of the Extragalactic Background Light at 3000, 5500, and 8000A (II): Measurement of Foreground Zodiacal Light

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    We present a measurement of the absolute surface brightness of the zodiacal light (3900-5100A) toward a fixed extragalactic target at high ecliptic latitude based on moderate resolution (~1.3A per pixel) spectrophotometry obtained with the du Pont 2.5m telescope at Las Campanas Observatory in Chile. This measurement and contemporaneous Hubble Space Telescope data from WFPC2 and FOS comprise a coordinated program to measure the mean flux of the diffuse extragalactic background light (EBL). The zodiacal light at optical wavelengths results from scattering by interplanetary dust, so that the zodiacal light flux toward any extragalactic target varies seasonally with the position of the Earth. This measurement of zodiacal light is therefore relevant to the specific observations (date and target field) under discussion. To obtain this result, we have developed a technique that uses the strength of the zodiacal Fraunhofer lines to identify the absolute flux of the zodiacal light in the multiple-component night sky spectrum. Statistical uncertainties in the result are 0.6% (1 sigma). However, the dominant source of uncertainty is systematic errors, which we estimate to be 1.1% (1 sigma). We discuss the contributions included in this estimate explicitly. The systematic errors in this result contribute 25% in quadrature to the final error in our coordinated EBL measurement, which is presented in the first paper of this series.Comment: Accepted for publication in ApJ, 22 pages using emulateapj.sty, version with higher resolution figures available at http://www.astro.lsa.umich.edu/~rab/publications.html or at http://nedwww.ipac.caltech.edu/level5/Sep01/Bernstein2/frames.htm

    Physics and Chemistry of the Hydrogen Fluoride Production Process from Fluorine Containing Waste

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    The impact of the aluminum industry wastes on the environment is established. The resource efficient method of aluminum industry fluorine-containing wastes processing, which includes wastes oxidizing roasting to remove carbon component and the interaction of fluorine- containing particles with sulfuric acid in order to produce hydrogen fluoride, is considered. The economic and environmental effect of the proposed processing method is substantiated

    Investigation of Exchange Current at Interface Aluminum | Chloroaluminate Ionic Liquid 1-Ethyl-3- Methylimidazolium Chloride by Impedance Spectroscopy

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    Впервые были измерены токи обмена на границе алюминия с хлоралюминатной ионной жидкостью (ИЖ) 1-этил-3-метилимидазолий хлорид методом фадеевского импеданса. Ток обмена на границе алюминия с кислой ИЖ, в которой присутствует анион Al2Cl7–, на 3 порядка выше тока обмена на границе алюминия с нейтральной ИЖ. Следовательно, ион Al2Cl7– является основной электроактивной частицей в расплаве. В кислых ИЖ ток обмена не зависит от мольной доли хлорида алюминия в ИЖ и составляет 1.6 мА∙см-2.The exchange currents at the interface between aluminum and chloroaluminate ionic liquid (IL) 1-ethyl-3-methylimidazolium chloride were measured for the first time by impedance spectroscopy. The exchange current values at the interface between aluminum and acidic IL is three orders of magnitude higher than at the interface between aluminum and neutral IL because of Al2Cl7– anion existence. Therefore, the Al2Cl7– ion is the main electroactive particle in the melt. The exchange current in acidic ILs does not depend on the molar fraction of aluminum chloride in IL and is equal to 1.6 mA∙cm-2

    Procjena izloženosti UV zračenju tijekom ljetnih mjeseci u Hrvatskoj s pomoću jednostavne približne formule

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    The Tropospheric Ultraviolet-Visible (TUV) model, version 4.2 developed by Madronich (2003) was usedto estimate the extent of ultraviolet (UV) exposure of general population in Croatia over the summer. Solarnoon values (13 h local time, CEST) of the ultraviolet index (UVI) for the period April to October 2004 were calculated for 61 cities in Croatia. The results showed that the risk of sunburn at 13 h local time inclear weather was high between April and September (UVI >7) and very high in July (UVI >10). In July, the UVI exceeded 8 between 11 h and 15 h local time. In this study, we developed a simple approximate formula to estimate UVI. The formula includes data on the time, date, altitude and clouds. The difference between our estimate and the TUV model for the summer months of June, July and August at 10 h to16 h local time was less than 10 %.Tropospheric Ultraviolet-Visible (TUV) model, verzija 4.2 autora S. Madronicha (2003.) upotrijebljen je zaprocjenu izloženosti ultraljubičastom (UV) zračenju stanovništva u Hrvatskoj. Podnevne vrijednosti (13 hprema lokalnom vremenu) ultraljubičastog indeksa (UVI) izračunane su za 61 mjesto u Hrvatskoj za razdobljetravanj - listopad. Rezultati pokazuju da je u 13 h prema lokalnom vremenu rizik od nastanka opeklina izazvanih sunčevim zračenjem u danima bez naoblake visok između travnja i rujna (UVI > 7) te da je rizikvrlo visok tijekom srpnja (UVI >10). U srpnju tijekom dana UV indeks prelazi vrijednost 8 između 11 h i15 h prema lokalnom vremenu. U ovom radu za procjenu UV indeksa razvijena je jednostavna približna formula. Formula omogućava procjenu UV indeksa na temelju podataka o datumu, satu, nadmorskoj visini i naoblaci. Prilikom usporedbe rezultata dobivenih formulom i točnih rezultata dobivenih TUV modelom za ljetne mjesece lipanj, srpanj i kolovoz te razdoblje od 10 h do 16 h među rezultatima dobivena je razlikamanja od 10 %

    Defining minimal invasive surgical therapy for benign prostatic obstruction surgery: Perspectives from a global knowledge, attitude, and practice survey

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    Objective: To scrutinize the definitions of minimal invasive surgical therapy (MIST) and to investigate urologists’ knowledge, attitudes, and practices for benign prostatic obstruction surgeries. Methods: A 36-item survey was developed with a Delphi method. Questions on definitions of MIST and attitudes and practices of benign prostatic obstruction surgeries were included. Urologists were invited globally to complete the online survey. Consensus was achieved when more than or equal to 70% responses were “agree or strongly agree” and less than or equal to 15% responses were “disagree or strongly disagree” (consensus agree), or when more than or equal to 70% responses were “disagree or strongly disagree” and less than or equal to 15% responses were “agree or strongly agree” (consensus disagree). Results: The top three qualities for defining MIST were minimal blood loss (n=466, 80.3%), fast post-operative recovery (n=431, 74.3%), and short hospital stay (n=425, 73.3%). The top three surgeries that were regarded as MIST were Urolift® (n=361, 62.2%), Rezum® (n=351, 60.5%), and endoscopic enucleation of the prostate (EEP) (n=332, 57.2%). Consensus in the knowledge section was achieved for the superiority of Urolift®, Rezum®, and iTIND® over transurethral resection of the prostate with regard to blood loss, recovery, day surgery feasibility, and post-operative continence. Consensus in the attitudes section was achieved for the superiority of Urolift®, Rezum®, and iTIND® over transurethral resection of the prostate with regard to blood loss, recovery, and day surgery feasibility. Consensus on both sections was achieved for EEP as the option with the better symptoms and flow improvement, lower retreatment rate, and better suitable for prostate more than 80 mL. Conclusion: Minimal blood loss, fast post-operative recovery, and short hospital stay were the most important qualities for defining MIST. Urolift®, Rezum®, and EEP were regarded as MIST by most urologists

    Global experience and progress in GreenLight-XPS 180-Watt photoselective vaporization of the prostate

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    Purpose: To evaluate changes in global perioperative data of GreenLight-XPS 180-Watt photo-selective vaporization of the prostate (GL-XPS) of the Global Greenlight Group (GGG) database. Methods: 3441 men, who underwent GL-XPS for symptomatic BPH between 2011 and 2019 at seven high volume international centers, were included. Primary outcome measurements were operative time (OT; min), effective laser time (LT; min of OT), as well as intraoperative and postoperative adverse events (AEs), all analyzed by year of surgery (2011–2019) and prostate volume (PV) group ( 150 ml). Results: The median age was 70 years (interquartile range 64–77), the median PV was 64 ml (IQR 47–90). The OT and LT slightly increased but stayed highly efficient all in all. Median OT was 60 min (IQR 45–83) and LT was 33 min (IQR 23–46). Median energy use was 253 kJ (IQR 170–375) with an energy density of 3.94 kJ/ml (IQR 2.94–5.02). The relative probability of perioperative AEs decreased by 17% each year (p  0.001). Conclusion: These findings from the GGG demonstrate significant improvement secondary to growing experience with GL-XPS between 2011 and 2019 in intraoperative AEs, including transfusions, and postoperative AEs. While staying highly efficient in OT and LT of GL-XPS within a 9-year period of experience
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