64 research outputs found
Unravelling the transport mechanism of pore-filled membranes for hydrogen separation
The permeation characteristics of palladium pore filled (PF) membranes have been investigated with gas permeation and structural characterization of the membranes. PF membranes have been prepared by filling with Pd the nanoporous γ-Al2O3/YSZ (or pure YSZ) layer supported onto porous α-Al2O3 and ZrO2. The number of nanoporous layers and the applied vacuum level during the electroless plating process have been studied. Gas permeation properties of the PF membranes have been determined in a temperature range of 300-550 °C. The measured hydrogen permeances have been found to be lower than previously reported for similar membranes. It has been found that the hydrogen fluxes do not depend on the thickness of the nanoporous layers (γ-Al2O3/YSZ or pure YSZ) or on the vacuum pump employed for filling with Pd. The physicochemical characterization performed showed that the palladium deposited does not form a percolated network across the mesoporous layer(s), leading to low hydrogen permeances and thus low H2/N2 perm-selectivities.The presented work is funded within FERRET project as part of European Union’s Seventh
Framework Programme (FP7/2007-2013) for the Fuel Cells and Hydrogen Joint Technology
Initiative under grant agreement n° 621181.
The Talos TEM was funded as part of HEFCE funding in the UK
Research Partnership Investment Funding (UKRPIF) Manchester RPIF Round 2
Spin-based quantum information processing with semiconductor quantum dots and cavity QED
A quantum information processing scheme is proposed with semiconductor
quantum dots located in a high-Q single mode QED cavity. The spin degrees of
freedom of one excess conduction electron of the quantum dots are employed as
qubits. Excitonic states, which can be produced ultrafastly with optical
operation, are used as auxiliary states in the realization of quantum gates. We
show how properly tailored ultrafast laser pulses and Pauli-blocking effects,
can be used to achieve a universal encoded quantum computing.Comment: RevTex, 2 figure
Life-cycle greenhouse gas emissions of portuguese olive oil
The main goal of this paper was to assess the greenhouse gas (GHG) intensity of olive oil production in Portugal. A life-cycle model and inventory were implemented for the entire production process, including a comprehensive analysis of olive cultivation, olive oil extraction, packaging, and distribution. Data originates from five differently-sized Portuguese olive growers and from a total of six olive oil mills, representing the three extraction processes in use: three-phase extraction, two-phase extraction, and traditional pressing. The results show that the GHG intensity lies in the range 1.8-8.2 kg CO2eq/liter and that the main contributors were fertilizers (production and field emissions). Efficient use of fertilizers thus seems to be a key factor for mitigating the GHG intensity of olive oil production
Semiconductor-based Geometrical Quantum Gates
We propose an implementation scheme for holonomic, i.e., geometrical, quantum
information processing based on semiconductor nanostructures. Our quantum
hardware consists of coupled semiconductor macroatoms addressed/controlled by
ultrafast multicolor laser-pulse sequences. More specifically, logical qubits
are encoded in excitonic states with different spin polarizations and
manipulated by adiabatic time-control of the laser amplitudes . The two-qubit
gate is realized in a geometric fashion by exploiting dipole-dipole coupling
between excitons in neighboring quantum dots.Comment: 4 Pages LaTeX, 3 Figures included. To appear in PRB (Rapid Comm.
Holonomic quantum gates: A semiconductor-based implementation
We propose an implementation of holonomic (geometrical) quantum gates by
means of semiconductor nanostructures. Our quantum hardware consists of
semiconductor macroatoms driven by sequences of ultrafast laser pulses ({\it
all optical control}). Our logical bits are Coulomb-correlated electron-hole
pairs (excitons) in a four-level scheme selectively addressed by laser pulses
with different polarization. A universal set of single and two-qubit gates is
generated by adiabatic change of the Rabi frequencies of the lasers and by
exploiting the dipole coupling between excitons.Comment: 10 Pages LaTeX, 10 Figures include
Interrogating trans and sexual identities through the conceptual lens of translocational positionality
This article explores the confluence of trans identity and sexuality drawing on the concept of translocational positionality. In this discussion, a broad spectrum of gendered positionalities incorporates trans identity which, in turn, acknowledges normative male and female identities as well as non-binary ones. It is also recognised, however, that trans identity overlaps with other positionalities (pertaining to sexuality, for example) to shape social location. In seeking to understand subject positions, a translocational lens acknowledges the contextuality and temporality of social categories to offer an analysis which recognises the overlaps and differentials of co-existing positionalities. This approach enables an analysis which explores how macro, or structural, contexts shape agency (at the micro-level) and also how both are mediated by trans people's multiple and shifting positionalities. In this framing, positionality represents a meso layer between structure and agency. Four case studies are presented using data from a qualitative study which explored trans people's experiences of family, intimacy and domestic abuse. We offer an original contribution to the emerging knowledge-base on trans sexuality by presenting data from four case studies. We do so whilst innovatively applying the conceptual lens of translocational positionality to an analysis which considers macro, meso and micro levels of influence
Life-cycle greenhouse gas emissions of portuguese olive oil
The main goal of this paper was to assess the greenhouse gas (GHG) intensity of olive oil production in Portugal. A life-cycle model and inventory were implemented for the entire production process, including a comprehensive analysis of olive cultivation, olive oil extraction, packaging, and distribution. Data originates from five differently-sized Portuguese olive growers and from a total of six olive oil mills, representing the three extraction processes in use: three-phase extraction, two-phase extraction, and traditional pressing. The results show that the GHG intensity lies in the range 1.8-8.2 kg CO2eq/liter and that the main contributors were fertilizers (production and field emissions). Efficient use of fertilizers thus seems to be a key factor for mitigating the GHG intensity of olive oil production
''Sex changes'? Paradigm shifts in 'sex' and 'gender' following the gender recognition act?'
Gender transformations are normatively understood as somatic, based on surgical reassignment, where the sexed body is aligned with the gender identity of the individual through genital surgery - hence the common lexicon 'sex change surgery'. We suggest that the UK Gender Recognition Act 2004 challenges what constitutes a 'sex change' through the Act's definitions and also the conditions within which legal 'recognition' is permitted. The sex/gender distinction, (where sex normatively refers to the sexed body, and gender, to social identity) is demobilised both literally and legally. This paper discusses the history of medico-socio-legal definitions of sex have been developed through decision making processes when courts have been faced with people with gender variance and , in particular, the implications of the Gender Recognition Act for our contemporary legal understanding of sex. We ask, and attempt to answer, has 'sex' changed
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