 ABSTRACT: TCarbon  dioxide  (CO2)  is  the  main  responsible  for  greenhouse  effect.  The  global concentration of CO2in the atmosphereis increasing mainly due to the emissions from fossil  fuel  combustion.  The  reduction  of  CO2by  photocatalysis  is  one  of  the  most promising  methods  since  CO2can  be  reduced  to  useful  compounds  by  irradiating  it with  UV  light  at  room  temperature  and  ambientpressure.  Several  semiconductors, titled p-type,  exhibit  suitable  band  energies  for  photocatalytic  reduction  of  carbon dioxide.  Among  various  catalysts,  copper  oxides  have  properties  that  leads  methanol and . Ler mais . . .

 ABSTRACT: The development of an alternative to fossil fuels isone of the big challenges of our society. There is an estimate that global energy consumption in the next 35 years will be almost double the current. Because of this, the expansion of the energy matrix using fossil-based fuels can lead to the collapse of the planet. Based on this scenario, it is indispensable to study alternative sources of energy to meet this demand. Many strategies for using renewable energy sources have been inspired by the natural photosynthetic system, where water can be used as a source of energy through the production of hydrogen and oxygen1,2. Ler mais . . .

 ABSTRACT: N recent years someprogress has been made about incorporation of Carbon Nanotubes –CNTs  in  metal  matrix  by  arc  welding.Despite  that, there  is  scarce  information relating tomicrostructural modifications induced by nanomaterial inthe welding metal.In  this  sense,we present  the  incorporation  of  nanocomposite  based  on  Nickel/Carbon Nanotubes@stainless  steel  316Lalloy–Ni-CNTs@316L   via  Gas  Tungsten   Arc Welding Pulsed –GTAW-P  in the surface of a  metal  matrix  based on  manganesesteel namely as  base  metal.  Themanufacturedspecimens with/without  nanocomposite were characterized by: optical  . Ler mais . . .

 ABSTRACT: Extraction with supercritical fluid is the combination of a set of unit operations, this extraction technique may represent an alternative to conventional methods, since it does not use organic solvents during the separation process, in the literature it is known as green extraction, and Depending on the parameters used during the extraction we may have a selectivity in the separation of high added value bioactive compounds, natural substances may represent a viable alternative in the search for new medicines and have various industrial applications such as in the food, cosmetic and pharmaceutical industries. Extraction with  . Ler mais . . .

 ABSTRACT: We have simulated electron tunneling through one-dimensional molecular junctions based on first-principles simulations using the density functional theory combined with the non-equilibrium Green's functions methodology.The bridging atom bonds weakly to the electrodes in both systems, it strongly affects the electronic transport properties, such as electron transmission, current–voltage relation, differential conductance, density of states and eigenchannels. This is demonstrated by comparing with the results obtained from the corresponding systems for both the 1D and the quasi-1D junctions in the absence of the central sodium atom. The revealed transport properties are sensitive to the molecular . Ler mais . . .

 ABSTRACT: Molecular  electronics  is  a  interdisciplinary  field  of  study  that  combines  several techniques  to  find  applications  of  molecules  as  components  of  integrated  circuits  and try  miniaturize  electronic  devices.  His  benefits  are  the  low  consume  of  energy, flexibility,  low  size,  etc.  The  analysis  of  molecules  that  are  in  biological  compounds provides other point of view to understand how the dynamic electronic configuration in these  systems  influences  the  biological  processes  in  plants  and  animals.  All  living mater  is  a  complex  electronic  device.  The  simplest  understanding  about  molecular electronics  in  biological  compo  . Ler mais . . .

 ABSTRACT: Energy is an essential asset to leverage the economic and social development of a country. In Brazil, hydroelectric power stations produce most of the electricity, but also generate numerous social and environmental impacts, high construction and distribution costs. Besides, there is a strong dependence on rainfall indices to maintain reservoir levels and river flow, showing that the national energy matrix needs to be expanded and better planned through diversification of its sources. Thus, it is evident the need for new proposals of alternative and decentralized energy sources, which electricity is generated near the consumer centers, facilitating the management, minimizing  . Ler mais . . .

 ABSTRACT: The present work seeks to use the solar oven as an alternative water disinfection resource and to  show  the  application,  the  procedures  are  performed  from  1000  mL  polyethylene  bottles containing water  from the Maratauíra River belonging to the municipality of  Abaetetuba-Pa. The  samples  were  taken  to  the  disciplinary  laboratory  of  the  Basílio  de  Carvalho  School where  the  prototype  of  the  solar  oven  was  assembled  telling  the  partnership  of  the  local Science  Club.  In  a  specific  area  surrounding  the  school,  the temperature  and  pH  of  the samples were measured at time intervals of one hou . Ler mais . . .

 ABSTRACT: We har . Ler mais . . .

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