The cusp anomalous dimension at three loops and beyond

We derive an analytic formula at three loops for the cusp anomalous dimension Gamma_cusp(phi) in N=4 super Yang-Mills. This is done by exploiting the relation of the latter to the Regge limit of massive amplitudes. We comment on the corresponding three loops quark anti-quark potential. Our result also determines a considerable part of the three-loop cusp anomalous dimension in QCD. Finally, we consider a limit in which only ladder diagrams contribute to physical observables. In that limit, a precise agreement with strong coupling is observed.Comment: 34 pages, 6 figures. v2: references added, typos correcte

Integrability, spin-chains and the AdS3/CFT2 correspondence

Building on arXiv:0912.1723, in this paper we investigate the AdS3/CFT2 correspondence using integrability techniques. We present an all-loop Bethe Ansatz (BA) for strings on AdS_3 x S^3 x S^3 x S^1, with symmetry D(2,1;alpha)^2, valid for all values of alpha. This construction relies on a novel, alpha-dependent generalisation of the Zhukovsky map. We investigate the weakly-coupled limit of this BA and of the all-loop BA for strings on AdS_3 x S^3 x T^4. We construct integrable short-range spin-chains and Hamiltonians that correspond to these weakly-coupled BAs. The spin-chains are alternating and homogenous, respectively. The alternating spin-chain can be regarded as giving some of the first hints about the unknown CFT2 dual to string theory on AdS_3 x S^3 x S^3 x S^1. We show that, in the alpha to 1 limit, the integrable structure of the D(2,1;alpha) model is non-singular and keeps track of not just massive but also massless modes. This provides a way of incorporating massless modes into the integrability machinery of the AdS3/CFT2 correspondence.Comment: LaTeX, 38 pages. v2: Corrected misprints in section 6.

Protected string spectrum in AdS(3)/CFT2 from worldsheet integrability

We derive the protected closed-string spectra of AdS3/CFT2 dual pairs with 16 supercharges at arbitrary values of the string tension and of the three-form fluxes. These follow immediately from the all-loop Bethe equations for the spectra of the integrable worldsheet theories. Further, representing the underlying integrable systems as spin chains, we find that their dynamics involves length-changing interactions and that protected states correspond to gapless excitations above the Berenstein-Maldacena-Nastase vacuum. In the case of AdS3 × S3 × T4 the degeneracies of such operators precisely match those of the dual CFT2 and the supergravity spectrum. On the other hand, we find that for AdS3 × S3 × S3 × S1 there are fewer protected states than previous supergravity calculations had suggested. In particular, protected states have the same su(2) charge with respect to the two three-spheres

New coal dust substitutes for bentonite moulding sands used in manufacture of castings from malleable iron and aluminium alloys

W artykule przedstawiono ważniejsze wyniki prac badawczo-rozwojowych i wdrożeniowych, zrealizowanych w ramach Projektów Celowych w latach 2006-2007, w dwóch krajowych odlewniach: Fabryce Łączników "Radom" w Radomiu oraz Odlewni MJM Jarosław Michalak w Ostrołęce. Celem projektów było opracowanie nowoczesnego, ekonomicznego oraz ekologicznego procesu produkcyjnego wykonywania odlewów. W Fabryce w Radomiu dotyczyło to odlewów łączników wykonywanych z żeliwa ciągliwego, w Odlewni MJM w Ostrołęce odlewów ze stopów aluminium (Al-Si) dla potrzeb energetyki. Opisano niektóre problemy odlewni związane z jakością produkowanych odlewów, zaproponowano optymalny sposób ich rozwiązania oraz przedstawiono wyniki badań dotyczących wprowadzonych rozwiązań, polegających na zastosowaniu w odlewniach nowego typu mas formierskich, zawierających w swoim składzie nowoczesny zamiennik odlewniczego pyłu węglowego o nazwie "kormix".The article discusses the most important results of research, development and implementation works conducted under Target Projects in years 2006-2007 at the two Polish foundries, i.e. "Radom" Fittings Factory in Radom and MJM Jarosław Michalak Foundry Shop in Ostrołęka. The aim of the projects was to develop a modern, economical and ecological process for the casting manufacture. In "Radom" Foundry the investigations were carried out on fittings and pipe connections cast from malleable iron; in MJM Foundry in Ostrołęka the examined castings were made from aluminium-silicon alloys and assigned for use by the power industry. Some problems faced by the Foundries in respect of casting quality were described, optimum solutions were searched, and the results of these searches were stated. The proposed solutions suggest using in foundry practice the moulding sands of a new type, containing in their composition the recently developed foundry coal dust substitute of the trade name "kormix"

Analiza naprowadzania bomby na cel naziemny z wykorzystaniem giroskopowego układu wykonawczego

This paper discusses the possibility of using a bomb flight control system in the form of a rapidly rotating heavy rotor jointly suspended in its body. Forced deflections of the rotor axis (gyroscope) in relation to the body axis generate torques, which change the direction of bomb flight and its guiding on the target. Some results of simulations are presented in a graphical form.W pracy rozważana jest możliwość wykorzystania pewnego układu wykonawczego sterowania lotem bomby w postaci szybko obracającego się ciężkiego wirnika zawieszonego przegubowo w jej korpusie. Wymuszone odchylania osi tego wirnika (giroskopu) względem osi korpusu generują momenty sił zmieniające kierunek lotu bomby i naprowadzanie jej na cel. Niektóre wyniki badań symulacyjnych zostały przedstawione w postaci graficznej

Kinematics and dynamic analysis of flying guided bomb unit equipped with target search and track gyroscopic system

W pracy dokonano analizy numerycznej dynamiki giroskopowego układu skanującego przestrzeń i śledzącego wykryty w niej cel, stanowiącego integralny obiekt kierowanej bomby lotniczej.In this article, the author describes numerical analysis of the dynamics of the detected target searched and tracked by gyroscopic search and track system. This system is an integral part of a guided bomb unit

Development of technology to manufacture "modified bentonite" used in production of steel castings with special regard to casting surface quality

W artykule przedstawiono ważniejsze wyniki prac badawczych rozwojowych i wdrożeniowych, zrealizowanych w ramach jednego z Projektów Celowych w wyniku współpracy pomiędzy Przedsiębiorstwem Techniczno Handlowym CERTECH w Niedomicach (producentem materiałów dla potrzeb odlewnictwa), a Instytutem Odlewnictwa w Krakowie. Celem projektu było opracowanie innowacyjnej technologii i uruchomienie produkcji "bentonitu zmodyfikowanego" przeznaczonego do wykonywania odlewów staliwnych o bardzo dobrej jakości powierzchni. Przedstawiono oraz omówiono wyniki badań dotyczących możliwości zastosowania dodatków węglowych w masie formierskiej przeznaczonej do wykonywania odlewów staliwnych, ich wpływu na jakość powierzchni odlewów, szczególnie na warstwę powierzchniową (naskórek odlewniczy), w aspekcie ewentualnego nawęglenia powierzchni odlewów. Efektem przedstawionych badań było opracowanie "bentonitu zmodyfikowanego", technologii jego wytwarzania oraz uruchomienie produkcji na skalę przemysłową.The article presents the most important results of the research, development and implementation studies carried out under one of the Target Projects as a result of cooperation between the CERTECH Technical and Commercial Enterprise at Niedomice (manufacturer of materials for foundry industry) and Foundry Research Institute in Cracow. The aim of the project was development of innovative technology and start up of the production of "modified bentonite" used in production of steel castings characterised by very high surface quality. The results of investigations regarding possible use of carbon additives to moulding sands for the manufacture of steel castings were presented and discussed, including the effect of these additives on casting surface quality, especially on casting skin in terms of its possible carburising. Studies were described, the final outcome of which was the development of "modified bentonite", the development of its manufacturing technology, and finally the start up of production

Application of a New Innovative Ceramic Material for Investment Casting Technology

The article presents the research results of a new ceramic material, in which olivine sand was used as the matrix. This new ceramic material was studied at the angle of its application in the investment casting technology. This material will be mainly used for preparing self-supporting moulds for castings made of aluminium and magnesium alloys, replacing the expensive material – molochite which has been used so far. The article presents the results of mineralogical research of olivine sand, as well as thermophysical research of the new ceramic material made on the olivine sand matrix. Comparative research of both materials was conducted, i.e. with the olivine and molochite matrix, then the assessment of the quality of the new ceramic material was made. What is more, the research results of the developed ceramics and its usefulness for the production of castings are presented

A R C H I V E S of F O U N D R Y E N G I N E E R I N G Application of a New Innovative Ceramic Material for Investment Casting Technology

Abstract The article presents the research results of a new ceramic material, in which olivine sand was used as the matrix. This new ceramic material was studied at the angle of its application in the investment casting technology. This material will be mainly used for preparing self-supporting moulds for castings made of aluminium and magnesium alloys, replacing the expensive material -molochite which has been used so far. The article presents the results of mineralogical research of olivine sand, as well as thermophysical research of the new ceramic material made on the olivine sand matrix. Comparative research of both materials was conducted, i.e. with the olivine and molochite matrix, then the assessment of the quality of the new ceramic material was made. What is more, the research results of the developed ceramics and its usefulness for the production of castings are presented

Effect of Wall Thickness on the Microstructure of Ductile Iron Castings Manufactured by the Inmold Process Using a Reaction Chamber

In the family of iron-based alloys, ductile iron enjoys the highest rate of development, finding application in various industries. Ductile iron or the cast iron with spheroidal graphite can be manufactured by various methods. One of them is the Inmold spheroidization process characterized by different technological solutions, developed mainly to increase the process efficiency. So far, however, none of the solutions has been based on the use of a reactor made outside the casting mould cavity. The method of spheroidization inside the casting mould using a reaction chamber developed at the Foundry Research Institute is an innovative way of cast iron treatment. The innovative character of this method consists in the use of properly designed and manufactured reactor placed in the casting mould cavity. Owing to this solution, the Inmold process can be carried out in moulds with both horizontal and vertical parting plane. The study presents the results of examinations of the microstructure of graphite precipitates and metal matrix of castings after spheroidization carried out by the Inmold process using a reactor and mould with vertical parting plane. Special pattern assembly was made for the tests to reproduce plates with wall thicknesses of 3; 5; 7; 10; 20 and 30 mm. The content of residual magnesium was determined for all tested castings, while for castings of plates with a wall thickness equal to or larger than 10 mm, testing of mechanical properties was additionally performed