Aging in super glassy polymers such as poly(trimethylsilylpropyne) (PTMSP), poly(4‐methyl‐2‐pentyne) (PMP), and polymers with intrinsic microporosity (PIM‐1) reduces gas permeabilities and limits their application as gas‐separation membranes. While super glassy polymers are initially very porous, and ultra‐permeable, they quickly pack into a denser phase becoming less porous and permeable. This age‐old problem has been solved by adding an ultraporous additive that maintains the low density, porous, initial stage of super glassy polymers through absorbing a portion of the polymer chains within its pores thereby holding the chains in their open position. This result is the first time that aging in super glassy polymers is inhibited whilst maintaining enhanced CO2 permeability for one year and improving CO2/N2 selectivity. This approach could allow super glassy polymers to be revisited for commercial application in gas separations.
Single-atom catalysts (SACs) offer many advantages, such as atom economy and high chemoselectivity; however, their practical application in liquid-phase heterogeneous catalysis is hampered by the productivity bottleneck as well as catalyst leaching. Flow chemistry is a well-established method to increase the conversion rate of catalytic processes, however, SAC-catalysed flow chemistry in packed-bed type flow reactor is disadvantaged by low turnover number and poor stability. In this study, we demonstrate the use of fuel cell-type flow stacks enabled exceptionally high quantitative conversion in single atom-catalyzed reactions, as exemplified by the use of Pt SAC-on-MoS2/graphite felt catalysts incorporated in flow cell. A turnover frequency of approximately 8000 h−1 that corresponds to an aniline productivity of 5.8 g h−1 is achieved with a bench-top flow module (nominal reservoir volume of 1 cm3), with a Pt1-MoS2 catalyst loading of 1.5 g (3.2 mg of Pt). X-ray absorption fine structure spectroscopy combined with density functional theory calculations provide insights into stability and reactivity of single atom Pt supported in a pyramidal fashion on MoS2. Our study highlights the quantitative conversion bottleneck in SAC-mediated fine chemicals production can be overcome using flow chemistry.
Aging in super glassy polymers such as poly(trimethylsilylpropyne) (PTMSP), poly(4‐methyl‐2‐pentyne) (PMP), and polymers with intrinsic microporosity (PIM‐1) reduces gas permeabilities and limits their application as gas‐separation membranes. While super glassy polymers are initially very porous, and ultra‐permeable, they quickly pack into a denser phase becoming less porous and permeable. This age‐old problem has been solved by adding an ultraporous additive that maintains the low density, porous, initial stage of super glassy polymers through absorbing a portion of the polymer chains within its pores thereby holding the chains in their open position. This result is the first time that aging in super glassy polymers is inhibited whilst maintaining enhanced CO2 permeability for one year and improving CO2/N2 selectivity. This approach could allow super glassy polymers to be revisited for commercial application in gas separations.
In September 2009, the British Government launched a new employment assistance model called Flexible New Deal. It was soon replaced by Work Programme in 2011. Both prioritized what is often called a 'black box' approach to public employment assistance, whereby the government purchaser focuses predominantly on outcomes and does not seek to direct agency operations. Using a study of the orientations and strategies of frontline employment services staff in 2008 and 2012, we seek to enhance understanding of the impact of so-called 'black box' commissioning on key aspects of service delivery. Black box advocates propose that it is a hands-off approach that allows agencies to be innovative and to improve efficiency. These effects are thought to be due to improved local service quality and greater flexibility to tailor services to individual clients. Critics argue that this increased discretion facilitates under-servicing of some jobseekers and agency profiteering. These practices are commonly referred to as 'parking' and 'creaming'. In this UK study, we provide evidence of both positive and negative activities associated with black box commissioning. We find some small improvements in flexibility at the frontline, but little to no evidence of increased efficiency as measured by the reported rates of jobseekers moving into work. We also observe an increase in practices associated with creaming and parking. We conclude that improving efficiency and maximizing innovation are not guaranteed by black box commissioning, and that the aim of facilitating increased frontline flexibility, while also minimizing risk, persists as a major policy design tension.
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