CO2 methanation over Ni-Al LDH-derived catalyst with variable Ni/Al ratio

CO2 methanation is a promising technology to recycle CO2 into useful chemicals, fuels, and energy, avoiding its emissions in the atmosphere, as well as for the purification of H2 streams containing CO2. In this work, Ni-Al LDH-derived catalysts with Ni/Al ratio between 0.5 and 4 were prepared by co-precipitation and evaluated in CO2 methanation. The samples were characterized by N2 physisorption, X-ray diffraction, temperature-programed reduction, temperature-programmed desorption (CO2-TPD, H2-TPD) and oxidation. Catalytic tests were carried out in a fixed-bed reactor at atmospheric pressure, inlet mixture of H2:CO2:N2 = 4:1:15 and GHSV = 60000 mL (gcat h)−1, in stepwise mode (200–400 °C) and stability at 300 °C. The catalysts presented high activity and selectivity, reaching 92.3 % of CO2 conversion at 300 °C, along with 100 % CH4 selectivity for the catalyst with NiAl = 2 due to its high number of weak-to-medium strength basic sites. The amount of H2-chemisorbed was higher for NiAl = 1, whereas the highest number of basic sites was for NiAl = 2. These results indicate that LDH-derived Ni-Al catalysts with a Ni/Al ratio between 1 and 2 would be suitable for CO2 methanation

Catalytic conversion of ethanol over ZSM-5-supported catalysts

O petróleo, fonte de energia não renovável, é a principal matéria-prima usada na produção de derivados como combustíveis, lubrificantes e petroquímicos básicos. Neste contexto o etanol, uma matéria-prima renovável, torna-se fonte para a obtenção de hidrocarbonetos de maior valor agregado, tais como, benzeno, tolueno, etc. Este trabalho teve como objetivo avaliar o efeito de diferentes metais suportados em zeólita HZSM-5 para a conversão do etanol em produtos com maior valor agregado. Duas séries de catalisadores foram preparadas com diferentes metais e diferentes teores de Ni em HZSM-5 comercial. As amostras foram caracterizadas por área específica SBET, DRX, TPD-NH3 e TPO. Os ensaios de atividade foram realizados em um reator tubular de leito fixo na faixa de temperatura entre 300 e 400 °C, usando etanol como reagente. Os resultados sugerem que o tipo e a quantidade de metal usado na modificação da zeólita HZSM-5 comercial influencia a seletividade para formação dos hidrocarbonetos superiores, bem como a temperatura de reação. A utilização de menores vazões favoreceu a formação de produtos pesados. A formação dos hidrocarbonetos superiores diminuiu ao longo da reação devido à deposição de carbono sobre a superfície do catalisador.The oil, a non-renewable energy source, is the main raw material used to produce derivatives such as fuels, lubricants and petrochemicals. In this context, ethanol, a renewable feedstock, becomes a source for obtaining high value-added hydrocarbons, such as benzene, toluene, etc. This work aimed to evaluate the effect of different metal catalysts supported on HZSM-5 zeolite for the ethanol conversion into products with higher added value. Two series of catalysts were prepared with different metals and different amounts of Ni on commercial HZSM-5. Samples were characterized by specific area SBET, XRD, NH3-TPD and TPO. The activity runs were carried out in a tubular fixed bed reactor in the temperature range between 300 and 400 °C, using ethanol as a reactant. The results suggest that the type and the amount of metal used for the modification of commercial HZSM-5 zeolite influence the selectivity for formation of higher hydrocarbons as well as the reaction temperature. The formation of heavy products was favored by low flow rates and it was found that the selectivity for higher hydrocarbons declined throughout the reaction due to the deposition of carbon over the catalyst

Removal of reactive red 120 on Fe-hydrotalcite : isotherms study

HDL-MgFe is a Hydrotalcite that represent a compound lamellar double hydroxide. It was prepared through the continuous co-preparation method. The solid was characterized by surface area measurements, X-ray diffraction and temperature-programmed desorption of CO2. The adsorbent was used for the adsorption of Reactive Red 120 dye, and the factors affecting the adsorption were discussed, including concentration of adsorbent solid and contact time. The adsorption isotherms data were fitted to the Langmuir, Freundlich, Redlich-Peterson, Sips and BET models. The most suitable adsorption conditionswere found at a contact time of 60 min and solidconcentrarion of 2g.L -1 . The results for MgFe hydrotalcite showed a high adsorption with percentage about 90% of dye removal. Langmuir and Redlich-Peterson models were the isotherms that best described the removal process

Conversion of furan over gallium and zinc promoted ZSM-5 : the effect of metal and acid sites

The addition of gallium or zinc to ZSM-5 increases the aromatic selectivity and decreases the olefin selectivity for furan conversion. Both the benzene and naphthalenes selectivities increase with small amounts of gallium or zinc addition. At 5 wt% metal loading this effect is more pronounced with zinc promoted ZSM-5 having about 25% higher benzene selectivity than the gallium promoted ZSM-5. Additionally, the decarbonylation and methane formation reactions were both increased by adding zinc or gallium to the catalyst. As zinc or gallium loading is increased, the amount of Brønsted acid sites decrease, while the quantity of Lewis acid sites increase. This effect was more pronounced with zinc, as a result of its greater effectiveness to exchange with protons at the Brønsted acid sites. The aromatic yield appears to correlate with this increase in Lewis acidity. The addition of zinc to ZSM-5 also altered the reaction chemistry occurring during the hydrolysis of furan, lowering propylene and increasing methane yields as zinc loading increased

New insights into the genetic etiology of Alzheimer's disease and related dementias

Characterization of the genetic landscape of Alzheimer's disease (AD) and related dementias (ADD) provides a unique opportunity for a better understanding of the associated pathophysiological processes. We performed a two-stage genome-wide association study totaling 111,326 clinically diagnosed/'proxy' AD cases and 677,663 controls. We found 75 risk loci, of which 42 were new at the time of analysis. Pathway enrichment analyses confirmed the involvement of amyloid/tau pathways and highlighted microglia implication. Gene prioritization in the new loci identified 31 genes that were suggestive of new genetically associated processes, including the tumor necrosis factor alpha pathway through the linear ubiquitin chain assembly complex. We also built a new genetic risk score associated with the risk of future AD/dementia or progression from mild cognitive impairment to AD/dementia. The improvement in prediction led to a 1.6- to 1.9-fold increase in AD risk from the lowest to the highest decile, in addition to effects of age and the APOE ε4 allele

Differential cross section measurements for the production of a W boson in association with jets in proton–proton collisions at √s = 7 TeV

Measurements are reported of differential cross sections for the production of a W boson, which decays into a muon and a neutrino, in association with jets, as a function of several variables, including the transverse momenta (pT) and pseudorapidities of the four leading jets, the scalar sum of jet transverse momenta (HT), and the difference in azimuthal angle between the directions of each jet and the muon. The data sample of pp collisions at a centre-of-mass energy of 7 TeV was collected with the CMS detector at the LHC and corresponds to an integrated luminosity of 5.0 fb[superscript −1]. The measured cross sections are compared to predictions from Monte Carlo generators, MadGraph + pythia and sherpa, and to next-to-leading-order calculations from BlackHat + sherpa. The differential cross sections are found to be in agreement with the predictions, apart from the pT distributions of the leading jets at high pT values, the distributions of the HT at high-HT and low jet multiplicity, and the distribution of the difference in azimuthal angle between the leading jet and the muon at low values.United States. Dept. of EnergyNational Science Foundation (U.S.)Alfred P. Sloan Foundatio

Impacts of the Tropical Pacific/Indian Oceans on the Seasonal Cycle of the West African Monsoon

The current consensus is that drought has developed in the Sahel during the second half of the twentieth century as a result of remote effects of oceanic anomalies amplified by local land–atmosphere interactions. This paper focuses on the impacts of oceanic anomalies upon West African climate and specifically aims to identify those from SST anomalies in the Pacific/Indian Oceans during spring and summer seasons, when they were significant. Idealized sensitivity experiments are performed with four atmospheric general circulation models (AGCMs). The prescribed SST patterns used in the AGCMs are based on the leading mode of covariability between SST anomalies over the Pacific/Indian Oceans and summer rainfall over West Africa. The results show that such oceanic anomalies in the Pacific/Indian Ocean lead to a northward shift of an anomalous dry belt from the Gulf of Guinea to the Sahel as the season advances. In the Sahel, the magnitude of rainfall anomalies is comparable to that obtained by other authors using SST anomalies confined to the proximity of the Atlantic Ocean. The mechanism connecting the Pacific/Indian SST anomalies with West African rainfall has a strong seasonal cycle. In spring (May and June), anomalous subsidence develops over both the Maritime Continent and the equatorial Atlantic in response to the enhanced equatorial heating. Precipitation increases over continental West Africa in association with stronger zonal convergence of moisture. In addition, precipitation decreases over the Gulf of Guinea. During the monsoon peak (July and August), the SST anomalies move westward over the equatorial Pacific and the two regions where subsidence occurred earlier in the seasons merge over West Africa. The monsoon weakens and rainfall decreases over the Sahel, especially in August.Peer reviewe

Optimasi Portofolio Resiko Menggunakan Model Markowitz MVO Dikaitkan dengan Keterbatasan Manusia dalam Memprediksi Masa Depan dalam Perspektif Al-Qur`an

Risk portfolio on modern finance has become increasingly technical, requiring the use of sophisticated mathematical tools in both research and practice. Since companies cannot insure themselves completely against risk, as human incompetence in predicting the future precisely that written in Al-Quran surah Luqman verse 34, they have to manage it to yield an optimal portfolio. The objective here is to minimize the variance among all portfolios, or alternatively, to maximize expected return among all portfolios that has at least a certain expected return. Furthermore, this study focuses on optimizing risk portfolio so called Markowitz MVO (Mean-Variance Optimization). Some theoretical frameworks for analysis are arithmetic mean, geometric mean, variance, covariance, linear programming, and quadratic programming. Moreover, finding a minimum variance portfolio produces a convex quadratic programming, that is minimizing the objective function ðð¥with constraintsð ð 𥠥 ðandð´ð¥ = ð. The outcome of this research is the solution of optimal risk portofolio in some investments that could be finished smoothly using MATLAB R2007b software together with its graphic analysis

Search for anomalous production of events with three or more leptons in pp collisions at √s = 8TeV

Published by the American Physical Society under the terms of the Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published articles title, journal citation, and DOI.A search for physics beyond the standard model in events with at least three leptons is presented. The data sample, corresponding to an integrated luminosity of 19.5fb-1 of proton-proton collisions with center-of-mass energy s=8TeV, was collected by the CMS experiment at the LHC during 2012. The data are divided into exclusive categories based on the number of leptons and their flavor, the presence or absence of an opposite-sign, same-flavor lepton pair (OSSF), the invariant mass of the OSSF pair, the presence or absence of a tagged bottom-quark jet, the number of identified hadronically decaying τ leptons, and the magnitude of the missing transverse energy and of the scalar sum of jet transverse momenta. The numbers of observed events are found to be consistent with the expected numbers from standard model processes, and limits are placed on new-physics scenarios that yield multilepton final states. In particular, scenarios that predict Higgs boson production in the context of supersymmetric decay chains are examined. We also place a 95% confidence level upper limit of 1.3% on the branching fraction for the decay of a top quark to a charm quark and a Higgs boson (t→cH), which translates to a bound on the left- and right-handed top-charm flavor-violating Higgs Yukawa couplings, λtcH and λctH, respectively, of |λtcH|2+|λctH|2<0.21

Repositioning of the global epicentre of non-optimal cholesterol

High blood cholesterol is typically considered a feature of wealthy western countries(1,2). However, dietary and behavioural determinants of blood cholesterol are changing rapidly throughout the world(3) and countries are using lipid-lowering medications at varying rates. These changes can have distinct effects on the levels of high-density lipoprotein (HDL) cholesterol and non-HDL cholesterol, which have different effects on human health(4,5). However, the trends of HDL and non-HDL cholesterol levels over time have not been previously reported in a global analysis. Here we pooled 1,127 population-based studies that measured blood lipids in 102.6 million individuals aged 18 years and older to estimate trends from 1980 to 2018 in mean total, non-HDL and HDL cholesterol levels for 200 countries. Globally, there was little change in total or non-HDL cholesterol from 1980 to 2018. This was a net effect of increases in low- and middle-income countries, especially in east and southeast Asia, and decreases in high-income western countries, especially those in northwestern Europe, and in central and eastern Europe. As a result, countries with the highest level of non-HDL cholesterol-which is a marker of cardiovascular riskchanged from those in western Europe such as Belgium, Finland, Greenland, Iceland, Norway, Sweden, Switzerland and Malta in 1980 to those in Asia and the Pacific, such as Tokelau, Malaysia, The Philippines and Thailand. In 2017, high non-HDL cholesterol was responsible for an estimated 3.9 million (95% credible interval 3.7 million-4.2 million) worldwide deaths, half of which occurred in east, southeast and south Asia. The global repositioning of lipid-related risk, with non-optimal cholesterol shifting from a distinct feature of high-income countries in northwestern Europe, north America and Australasia to one that affects countries in east and southeast Asia and Oceania should motivate the use of population-based policies and personal interventions to improve nutrition and enhance access to treatment throughout the world.Peer reviewe