47,003 research outputs found
Evaluation of microfiltration for the treatment of spent cutting-oil
A pilot plant using ceramic microfiltration membranes which could be regularly back-flushed with air for fouling control was evaluated for the treatment of spent cutting-oil. It was found that membrane fouling could be effectively controlled with regular air back-flushes (every 3 min for 1 s) and chemical cleaning using caustic soda. Permeate flux remained approximately constant and varied from 78 to 126 ./hEm2 for the first six runs and from 114 to 150 ./hEm2 for three more runs. An increase in feed temperature from ambient to 40‹C and cleaning of the membrane with 1% caustic soda, increased permeate flux from 183 to 282 ./hEm2 and from 195 to 264 ./hEm2 in two more runs. Excellent COD (75.5 to 90.3%) and O&G (97.2 to 99.1%) removals were obtained. The permeate quality should be suitable for discharge to the municipal sewer system (O&G < 500 mg/.) and the concentrated oil should be a useful energy source. Treatment of spent cutting-oil with microfiltration rather thanlandfilling should save valuable landfilling space
Higher Loop Spin Field Correlators in D=4 Superstring Theory
We develop calculational tools to determine higher loop superstring
correlators involving massless fermionic and spin fields in four space time
dimensions. These correlation functions are basic ingredients for the
calculation of loop amplitudes involving both bosons and fermions in D=4
heterotic and superstring theories. To obtain the full amplitudes in Lorentz
covariant form the loop correlators of fermionic and spin fields have to be
expressed in terms of SO(1,3) tensors. This is one of the main achievements in
this work.Comment: 59 pages, 1 figure; v2: final version published in JHE
Chaos around Holographic Regge Trajectories
Using methods of Hamiltonian dynamical systems, we show analytically that a
dynamical system connected to the classical spinning string solution
holographically dual to the principal Regge trajectory is non-integrable. The
Regge trajectories themselves form an integrable island in the total phase
space of the dynamical system. Our argument applies to any gravity background
dual to confining field theories and we verify it explicitly in various
supergravity backgrounds: Klebanov-Strassler, Maldacena-Nunez, Witten QCD and
the AdS soliton. Having established non-integrability for this general class of
supergravity backgrounds, we show explicitly by direct computation of the
Poincare sections and the largest Lyapunov exponent, that such strings have
chaotic motion.Comment: 28 pages, 5 figures. V3: Minor changes complying to referee's
suggestions. Typos correcte
The LippmannâSchwinger Formula and One Dimensional Models with Dirac Delta Interactions
We show how a proper use of the LippmannâSchwinger equation simplifies the calculations to obtain scattering states for one dimensional systems perturbed by N Dirac delta equations. Here, we consider two situations. In the former, attractive Dirac deltas perturbed the free one dimensional Schrödinger Hamiltonian. We obtain explicit expressions for scattering and Gamow states. For completeness, we show that the method to obtain bound states use comparable formulas, although not based on the LippmannâSchwinger equation. Then, the attractive N deltas perturbed the one dimensional Salpeter equation. We also obtain explicit expressions for the scattering wave functions. Here, we need regularisation techniques that we implement via heat kernel regularisation
Targeting Poverty in the Courts: Improving the Measurement of Ability to Pay
Ability-to-pay determinations are essential when governments use money-based alternative sanctions, like fines, to enforce laws. One longstanding difficulty in the U.S. has been the extreme lack of guidance on how courts are to determine a litigantâs ability to pay. The result has been a seat-of-the-pants approach that is inefficient and inaccurate, and, as a consequence, very socially costly. Fortunately, online platform technology presents a promising avenue for reform. In particular, platform technology offers the potential to increase litigant access, reduce costs, and ensure consistent and fair treatmentâall of which should lead to more accurate sanctions. We use interviews, surveys, and case-level data to evaluate and discuss the experiences of six courts that recently adopted an online ability-to-pay assessment tool that streamlines and standardizes ability-to-pay determinations. Our findings suggest that the online tool improves accuracy and therefore the effectiveness of fines as punishments, and so it may make the use of fines as sanctions more socially attractive
Eotaxin: a potent eosinophil chemoattractant cytokine detected in a guinea pig model of allergic airways inflammation.
Eosinophil accumulation is a prominent feature of allergic inflammatory reactions, such as those occurring in the lung of the allergic asthmatic, but the endogenous chemoattractants involved have not been identified. We have investigated this in an established model of allergic inflammation, using in vivo systems both to generate and assay relevant activity. Bronchoalveolar lavage (BAL) fluid was taken from sensitized guinea pigs at intervals after aerosol challenge with ovalbumin. BAL fluid was injected intradermally in unsensitized assay guinea pigs and the accumulation of intravenously injected 111In-eosinophils was measured. Activity was detected at 30 min after allergen challenge, peaking from 3 to 6 h and declining to low levels by 24 h. 3-h BAL fluid was purified using high performance liquid chromatography techniques in conjunction with the skin assay. Microsequencing revealed a novel protein from the C-C branch of the platelet factor 4 superfamily of chemotactic cytokines. The protein, eotaxin, exhibits homology of 53% with human MCP-1, 44% with guinea pig MCP-1, 31% with human MIP-1α, and 26% with human RANTES. Laser desorption time of flight mass analysis gave four different signals (8.15, 8.38, 8.81, and 9.03 kD), probably reflecting differential O-glycosylation. Eotaxin was highly potent, inducing substantial 111In-eosinophil accumulation at a 1-2-pmol dose in the skin, but did not induce significant 111In-neutrophil accumulation. Eotaxin was a potent stimulator of both guinea pig and human eosinophils in vitro. Human recombinant RANTES, MIP-1α, and MCP-1 were all inactive in inducing 111In-eosinophil accumulation in guinea pig skin; however, evidence was obtained that eotaxin shares a binding site with RANTES on guinea pig eosinophils. This is the first description of a potent eosinophil chemoattractant cytokine generated in vivo and suggests the possibility that similar molecules may be important in the human asthmatic lung
Lexicographic cones and the ordered projective tensor product
We introduce lexicographic cones, a method of assigning an ordered vector
space \Lex(S) to a poset , generalising the standard lexicographic cone.
These lexicographic cones are then used to prove that the projective tensor
cone of two arbitrary cones is a cone, and to find a new characterisation of
finite-dimensional vector lattices.Comment: 8 page
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