The GL-l.u.st.\ constant and asymmetry of the Kalton-Peck twisted sum in finite dimensions

We prove that the Kalton-Peck twisted sum $Z_2^n$ of $n$-dimensional Hilbert spaces has GL-l.u.st.\ constant of order $\log n$ and bounded GL constant. This is the first concrete example which shows different explicit orders of growth in the GL and GL-l.u.st.\ constants. We discuss also the asymmetry constants of $Z_2^n$

Non-linear evolution of a second mode wave in supersonic boundary layers

The nonlinear time evolution of a second mode instability in a Mach 4.5 wall-bounded flow is computed by solving the full compressible, time-dependent Navier-Stokes equations. High accuracy is achieved by using a Fourier-Chebyshev collocation algorithm. Primarily inviscid in nature, second modes are characterized by high frequency and high growth rates compared to first modes. Time evolution of growth rate as a function of distance from the plate suggests this problem is amenable to the Stuart-Watson perturbation theory as generalized by Herbert

The modern technology of iron and steel production and possible ways of their development

В изменяющейся мировой обстановке на рынке сырых материалов для черной металлургии разрабатывается ряд новых технологий по производству чугуна и стали, альтернативных существующим технологиям, которые способны обеспечить экономически устойчивую работу металлургических компаний. В дополнении к этому фокусируется внимание на экономии энергии и снижении выбросов парниковых газов в целях решения важнейших вопросов охраны окружающей среды. Изменение состояния окружающей среды ставит новые проблемы перед металлургической промышленностью, потребляющей значительные энергетические и топливные ресурсы. Отрасль вынуждена сосредоточить свое внимание на сокращении всех видов энергии, что приведет и к снижению выброса парниковых газов. Разработка альтернативных технологических процессов производства чугуна и стали способна обеспечить металлургическим компаниям экономически выгодную и устойчивую работу в производстве стали. Для оценки воздействий деятельности металлургических компаний на окружающую среду Инженерно-консалтинговой компанией ХАТЧ (НАТСH, Сanada) были разработаны новые методики моделирования, позволяющие квалифицированно и качественно оценивать риски в потреблении энергии и выбросах СО2 в металлургической промышленности. Методика для анализа выбросов углеродсодержащих парниковых газов названа G-CAP ™ (Зеленый Дом — Борьба с загрязнением воздуха углекислым газом), а для анализа энергоэффективности — En-MAPTM (Планирование действий при управлении энергией). Оценка существующего положения в большинстве интегрированных заводов показала, что они располагают возможностями по экономии энергии и борьбы с загрязнением атмосферы парниковыми газами, лучшие из этих заводов исчерпали эти возможности даже при высоких ценах на квоты выбросов СО2. В этом контексте важно оценить те важные особенности альтернативных технологий получения чугуна и стали, которые разработаны к настоящему времени. Эта статья содержит сравнительную оценку энергоэффективности и выбросов ПГ для некоторых выбранных альтернативных технологий производства чугуна и стали, которые рассматриваются для их реализации. Для этого применены методики G-CAP ™ и G-CAP ™ , элементы которых были разработаны в компании HATCH с основной целью количественной и квалификационной оценки потенциала экономии энергии и сокращения выбросов СО2 в металлургической промышленностиIn the changing global market scenario for raw materials for the steel industry, a number of novel iron and steelmaking process technologies are being developed to provide the steel companies with economically-sustainable alternatives for iron and steel-making. In addition, the steel industry is also focusing on reduction of energy consumption as well as green-house gas (GHG) emissions to address the crucial subject of climate change. Climate change is presenting new risks to the highly energy and carbon-intensive, iron and steel industry. The industry needs to focus on reduction of energy consumption as GHG emissions to address climate change. Development of alternate iron and steelmaking process technologies can provide steel companies with economically-sustainable alternatives for steel production. For managing climate change risks, novel modelling tools have been developed by Hatch to quantify and qualify potential energy savings and CO2 abatement within the iron and steel industry. The tool developed for abatement of greenhouse gas carbon is called G-CAPTM (Green-House Gas Carbon Abatement Process) while that developed for improving energy efficiency is called En-MAPTM (Energy Management Action Planning). Evaluation of existing operations have shown that most integrated plants have GHG and energy abatement opportunities; on the other hand, the best-in-class plants may not have a lot of low-risk abatement opportunities left, even at high CO2 price. In this context, it is important to assess these critical issues for the alternate iron and steelmaking technologies that have been developed. This paper presents a comparative evaluation of energy-efficiency and GHG emissions for some selected iron- and steelmaking technologies that are being considered for implementation. In this work, Hatch’s G-CAP™ and En-MAP™ tools that were developed with the main objective of quantifying and qualifying the potential energy savings and CO2 abatement within the iron and steel industry, were employed in the evaluation conducted

Towards a Better System for Immigration Control

We study different methods of immigration control using a simple model of a congested world. Our main comparison involves quota, the predominant instrument of immigration control, and a proposed system of immigration tolls and emigration subsidies. We show that the equilibrium of the proposed system is Pareto superior to the quota system. This is consistent with the tolls and subsidies creating a market for international migrants. When countries are price-takers the market becomes perfect and the exploitation of gains from trade complete. From a normative perspective, an open-borders policy is preferred to both control methods but will meet political opposition because it hurts the residents of the rich country.

Quantitation of Haemopoietic Cells from Normal and Leukaemic RFM Mice Using an In Vivo Colony Assay

The conventional diffusion chamber (CDC) as described by Benestad (1970) had been modified to assay the colony forming capacity of RFM bone marrow and spleen cells in agar diffusion chambers (ADCs). The colonies are morphologically identical to those formed by the CFUc in agar culture in vitro and have an incidence of approximately 1 in 103 normal nucleated bone marrow cells, and 1 in 104 nucleated spleen cells. Comparison of the growth of normal bone marrow cells in CDCs and in ADCs suggests that cell proliferation in diffusion chambers may result from the same precursor cell as detected by colony formation in agar culture in vitro. This proposal is supported by the suicide of approximately 46% of the ADC colony precursor cells following incubation with 3H-labelled thymidine

The analysis and simulation of compressible turbulence

Compressible turbulent flows at low turbulent Mach numbers are considered. Contrary to the general belief that such flows are almost incompressible, (i.e., the divergence of the velocity field remains small for all times), it is shown that even if the divergence of the initial velocity field is negligibly small, it can grow rapidly on a non-dimensional time scale which is the inverse of the fluctuating Mach number. An asymptotic theory which enables one to obtain a description of the flow in terms of its divergence-free and vorticity-free components has been developed to solve the initial-value problem. As a result, the various types of low Mach number turbulent regimes have been classified with respect to the initial conditions. Formulae are derived that accurately predict the level of compressibility after the initial transients have disappeared. These results are verified by extensive direct numerical simulations of isotropic turbulence

Stimulation of granulocytic colony formation in agar diffusion chambers implanted in cyclophosphamide pretreated mice.

The growth of mouse bone marrow colonies in agar diffusion chambers (ADCs) was evaluated using host mice injected with saline or with cyclophosphamide (CY) before chamber insertion. The mice pretreated with cyclophosphamide proved more effective hosts than control (saline pretreated) mice, indicating that cyclophosphamide causes the elaboration of a stimulating factor acting on colony precursor cells. Assays of the factor for colony stimulating activity against mouse bone marrow cells in agar culture in vitro suggest that potentiation may be due to a slight temporary increase in the level of colony stimulating factor (CSF) in the chamber environment, although a parallel increase was not detected in the serum. Stem cell recovery from the ADCs, measured by spleen colony formation, suggests that the stimulus may act by increasing differentiation at the level of the pluripotential stem cell

Remarks on the Central Limit Theorem for Non-Convex Bodies

In this note, we study possible extensions of the Central Limit Theorem for non-convex bodies. First, we prove a Berry-Esseen type theorem for a certain class of unconditional bodies that are not necessarily convex. Then, we consider a widely-known class of non-convex bodies, the so-called p-convex bodies, and construct a counter-example for this class

A deterministic alternative to the full configuration interaction quantum Monte Carlo method

Development of exponentially scaling methods has seen great progress in tackling larger systems than previously thought possible. One such technique, full configuration interaction quantum Monte Carlo, is a useful algorithm that allows exact diagonalization through stochastically sampling determinants. The method derives its utility from the information in the matrix elements of the Hamiltonian, along with a stochastic projected wave function, to find the important parts of Hilbert space. However, the stochastic representation of the wave function is not required to search Hilbert space efficiently, and here we describe a highly efficient deterministic method to achieve chemical accuracy for a wide range of systems, including the difficult Cr$_{2}$ dimer. In addition our method also allows efficient calculation of excited state energies, for which we illustrate with benchmark results for the excited states of C$_{2}$.Comment: 4 pages, 2 figure