A review of air-fuel mixing and alternative methods in scramjets and scramjet-like engines.

This paper reviews work on two aspects of scramjet and similar ducted hypersonic propulsion. The first of these is air-fuel mixing techniques - the problem of mixing is considered the most intractable in scramjet design. The second aspect is the use of innovative techniques to supplement mixing or provide an alternative to combustion altogether. The paper outlines the mixing problem and reviews both classic treatments and newer, more innovative, work. In the light of this it also outlines conclusions and points out gaps in current knowledge and areas where more research is needed

Legal Pathways to Deep Decarbonization in the United States

Legal Pathways to Deep Decarbonization in the United States provides a “legal playbook” for deep decarbonization in the United States, identifying well over 1,000 legal options for enabling the United States to address one of the greatest problems facing this country and the rest of humanity. The book is based on two reports by the Deep Decarbonization Pathways Project (DDPP) that explain technical and policy pathways for reducing U.S. greenhouse gas emissions by at least 80% from 1990 levels by 2050. This 80x50 target and similarly aggressive carbon abatement goals are often referred to as deep decarbonization, distinguished because it requires systemic changes to the energy economy. Legal Pathways explains the DDPP reports and then addresses in detail 35 different topics in as many chapters. These 35 chapters cover energy efficiency, conservation, and fuel switching; electricity decarbonization; fuel decarbonization; carbon capture and negative emissions; non-carbon dioxide climate pollutants; and a variety of cross-cutting issues. The legal options involve federal, state, and local law, as well as private governance. Authors were asked to include all options, even if they do not now seem politically realistic or likely, giving Legal Pathways not just immediate value, but also value over time. While both the scale and complexity of deep decarbonization are enormous, this book has a simple message: deep decarbonization is achievable in the United States using laws that exist or could be enacted. These legal tools can be used with significant economic, social, environmental, and national security benefits.https://scholarship.law.columbia.edu/books/1000/thumbnail.jp

America\u27s Zero Carbon Action Plan: Federal Legislative and Administrative Framework

This chapter sets out proposed federal laws and policies for America\u27s Zero Carbon Action Plan, a comprehensive report on how to achieve net-zero carbon emissions by 2050. This chapter sets forth recommendations for all four pillars of deep decarbonization – electricity decarbonization, energy efficiency and conservation, electrification of transportation and buildings, and carbon capture. It is supplemented with recommendations for significant reductions in emissions of non-carbon dioxide pollutants, as well as for changes in foreign policy. Each set of recommendations is accompanied by an explanation of the underlying strategy for the proposed changes

Reducing the number of miscreant tasks executions in a multi-use cluster.

Exploiting computational resources within an organisation for more than their primary task offers great benefits – making better use of capital expenditure and provides a pool of computational power. This can be achieved through the deployment of a cycle stealing distributed system, where tasks execute during the idle time on computers. However, if a task has not completed when a computer returns to its primary function the task will be preempted, wasting time (and energy), and is often reallocated to a new resource in an attempt to complete. This becomes exacerbated when tasks are incapable of completing due to excessive execution time or faulty hardware / software, leading to a situation where tasks are perpetually reallocated between computers – wasting time and energy. In this work we investigate techniques to increase the chance of ‘good’ tasks completing whilst curtailing the execution of ‘bad’ tasks. We demonstrate, through simulation, that we could have reduce the energy consumption of our cycle stealing system by approximately 50%

The triggering of MHD instabilities through photospheric footpoint motions

The results of 3D numerical simulations modelling the twisting of a coronal loop due to photospheric vortex motions are presented. The simulations are carried out using an initial purely axial field and an initial equilibrium configuration with twist, . The non-linear and resistive evolutions of the instability are followed. The magnetic field is twisted by the boundary motions into a loop which initially has boundary layers near the photospheric boundaries as has been suggested by previous work. The boundary motions increase the twist in the loop until it becomes unstable. For both cases the boundary twisting triggers the kink instability. In both cases a helical current structure wraps itself around the kinked central current. This current scales linearly with grid resolution indicating current sheet formation. For the cases studied 35-40% of the free magnetic energy is released. This is sufficient to explain the energy released in a compact loop flare

Simulations of a lattice model of two-headed linear amphiphiles: influence of amphiphile asymmetry

Using a 2D lattice model, we conduct Monte Carlo simulations of micellar aggregation of linear-chain amphiphiles having two solvophilic head groups. In the context of this simple model, we quantify how the amphiphile architecture influences the critical micelle concentration (CMC), with a particular focus on the role of the asymmetry of the amphiphile structure. Accordingly, we study all possible arrangements of the head groups along amphiphile chains of fixed length $N=12$ and 16 molecular units. This set of idealized amphiphile architectures approximates many cases of symmetric and asymmetric gemini surfactants, double-headed surfactants and boloform surfactants. Consistent with earlier results, we find that the number of spacer units $s$ separating the heads has a significant influence on the CMC, with the CMC increasing with $s$ for $s<N/2$. In comparison, the influence of the asymmetry of the chain architecture on the CMC is much weaker, as is also found experimentally.Comment: 30 pages, 17 fgure

Two complete syntheses of (S)-aspartate semi-aldehyde and demonstration that Delta(2)-tetrahydroisophthalic acid is a non-competitive inhibitor of dihydrodipicolinate synthase

The document attached has been archived with permission from the publisher.We report, in full, two 3-step syntheses of (S)-aspartate semi-aldehyde, an important synthetic and biosynthetic precursor, from diprotected aspartic acid. The first synthesis proceeds via a thioester, the second via a Weinreb amide. Each route yields pure (S)-aspartate semi-aldehyde in excellent yield. The utility of (S)-aspartate semi-aldehyde prepared in this manner was demonstrated with an inhibition study of dihydrodipicolinate synthase, wherein Δ2- tetrahydroisophthalic acid is shown to be a non-competitive inhibitor with respect to both substrates.Sarah J. Roberts, Jonathan C. Morris, Renwick C.J. Dobson, Chris L. Baxter, and Juliet A. Gerrar

Mimicking the impact of infant tongue peristalsis on behaviour of solid oral dosage forms administered during breastfeeding

An in vitro simulation system was developed to study the effect of an infant’s peristaltic tongue motion during breastfeeding on oral rapidly disintegrating tablets in the mouth, for use in rapid product candidate screening. These tablets are being designed for use inside a modified nipple shield worn by a mother during breastfeeding, a proposed novel platform technology to administer drugs and nutrients to breastfeeding infants. In this study, the release of a model compound, sulforhodamine B, from tablet formulations was studied under physiologically relevant forces induced by compression and rotation of a tongue mimic. The release profiles of the sulforhodamine B in flowing deionised water were found to be statistically different using 2-way ANOVA with matching, when tongue mimic rotation was introduced for two compression levels representing two tongue strengths (P=0.0013 and P<0.0001 for the lower and higher compression settings, respectively). Compression level was found to be a significant factor for increasing model compound release at rotational rates representing non-nutritive breastfeeding (P=0.0162). This novel apparatus is the first to simulate the motion and pressures applied by the tongue, and could be used in future infant oral product development

Styrene degradation in perlite biofilter: the overall performance characteristics and dynamic response

[Abstract] Styrene’s degradation in a perlite biofilter including the long-term operation, dynamic response to step-changes in inlet concentration and non-use periods were tested. The study was performed in a bench-scale biofilter with ID 100 mm and a bed height of 1 m. Perlite with a particle size of 2 – 4 mm was used as a packing material. An enrichment mixed culture was immobilized on the packing. The inoculum was obtained from a styrene biofilter. Two different loading conditions were tested: (1) Loading with a high inlet concentration and a high residence time. (2) Loading with a low inlet concentration and the low residence time. Both conditions are common in industrial practice. The dynamic response to a repeated step-change in the inlet concentration (from 50 to 200 mg.m-3) was tested. The dynamic behaviour of the restarting period after varying periods of non-use was also investigated. The results demonstrate a high biofilter stability under extreme loading conditions and also during the step-changes of the inlet concentration. The non-use periods tested had almost no effect on the biofilter performance. The maximum outlet concentration after the restarting of the load was 4 mg.m-3, when a 95 hours idle period was used. After shorter idle periods, the outlet styrene concentrations did not exceed 0.6 mg.m-3