Обоснование параметров канатных анкеров для крепления выработок в условиях слоистых пород

Purpose. The development of approaches to the substantiation of the cable bolts installation parameters for the mine workings supporting in conditions of laminated rocks, taking into account the geometric parameters of the rocks disintegration zone. Methods. The parameters of the rocks disintegration zone in the roof of a single mine working and a mine working in the area of a longwall influence are determined by the in-situ investigations. Findings. The existing approaches to the cable bolt installation parameters are considered. The rock deformation mechanism around a single mine working is introduced. The results of the experimental supporting of mine working with roof bolts in conditions of Western Donbass are analyzed. The results of studying of rock mass deformation in the roof of the gateroad in the area of longwall influence are presented. Originality. The deformation of the rock mass around a single mine working occurs in the form of extrusion wedges of laminated rocks in the roof and floor. Behind longwall face the zone of rocks disintegration formed at a height of 6 m in the roof and the overlying strata sagged by up to 0.2 m without delaminating. Practical implications. Taking into account the geometric parameters of the rocks disintegration zones the installation parameter of cable bolts for the mine working roof supporting are substantiated. Experiments proved that the increasing of the cable bolt installation density reduces the intensity of the gateroad roof rock deformation at the face – end.Цель. Разработка подходов к обоснованию параметров установки канатных анкеров с учетом геометрических параметров зоны дезинтеграции пород для крепления выработок в условиях слоистых пород. Методика. Натурными исследованиями установлены параметры зон дезинтеграции пород кровли одиночной выработки и выработки в зоне влияния очистных работ. Результаты. Рассмотрены существующие способы обоснования параметров установки канатных анкеров. Приведен механизм деформирования пород вокруг одиночной выработки. Проанализированы результаты эксперимента по креплению выработки анкерной крепью в условиях Западного Донбасса. Приведены результаты исследований закономерностей деформирования пород кровли подготовительной выработки в зоне влияния очистных работ. Научная новизна. Деформирование массива пород вокруг одиночной выработки происходит в виде формирования клиньев выдавливания слоистых пород почвы и кровли. За очистным забоем зона дезинтеграции пород формируется на высоту 6 м в кровлю выработки, а вышележащий массив опускается на величину до 0.2 м без расслоений. Практическая значимость. С учетом геометрических параметров зон дезинтеграции обоснованы параметры установки канатных анкеров для крепления кровли выработок в условиях слоистых пород. Экспериментально установлено, что увеличение плотности установки канатных анкеров приводит к уменьшению интенсивности деформирования пород кровли выработки на сопряжении “лава – штрек”.Мета. Розробка підходів до обґрунтування параметрів установки канатних анкерів з урахуванням геометри- чних параметрів зони дезінтеграції порід для кріплення виробок в умовах шаруватих порід. Методика. Натурними дослідженнями встановлено параметри зон дезінтеграції порід покрівлі одиночної виробки та виробки у зоні впливу очисних робіт. Результати. Розглянуто існуючі способи обґрунтування параметрів установки канатних анкерів. Наведено механізм деформування порід навколо одиночної виробки. Проаналізовано результати експерименту з кріплення виробки анкерним кріпленням в умовах Західного Донбасу. Наведено результати досліджень закономірностей деформування порід покрівлі підготовчої виробки у зоні впливу очисних робіт. Наукова новизна. Деформування масиву порід навколо одиночної виробки відбувається у вигляді формування клинів видавлювання шаруватих порід підошви та покрівлі. За очисним забоєм зона дезінтеграції порід формується на висоту 6 м у покрівлю виробки, а вищезалягаючий масив опускається на величину до 0.2 м без розшарувань. Практична значимість. З урахуванням геометричних параметрів зон дезінтеграції обґрунтовані параметри установки канатних анкерів для кріплення покрівлі виробок в умовах шаруватих порід. Експериментально встановлено, що збільшення щільності установки канатних анкерів призводить до зменшення інтенсивності деформування порід покрівлі виробки на сполученні “лава – штрек”.Авторы выражают свою искреннюю благодарность коллективу инженерно-технических работников ш. “Самарская” и ш. “Степная” за помощь в организации и проведении натурных наблюдений в горных выработках

Hyperbolicity Measures "Democracy" in Real-World Networks

We analyze the hyperbolicity of real-world networks, a geometric quantity that measures if a space is negatively curved. In our interpretation, a network with small hyperbolicity is "aristocratic", because it contains a small set of vertices involved in many shortest paths, so that few elements "connect" the systems, while a network with large hyperbolicity has a more "democratic" structure with a larger number of crucial elements. We prove mathematically the soundness of this interpretation, and we derive its consequences by analyzing a large dataset of real-world networks. We confirm and improve previous results on hyperbolicity, and we analyze them in the light of our interpretation. Moreover, we study (for the first time in our knowledge) the hyperbolicity of the neighborhood of a given vertex. This allows to define an "influence area" for the vertices in the graph. We show that the influence area of the highest degree vertex is small in what we define "local" networks, like most social or peer-to-peer networks. On the other hand, if the network is built in order to reach a "global" goal, as in metabolic networks or autonomous system networks, the influence area is much larger, and it can contain up to half the vertices in the graph. In conclusion, our newly introduced approach allows to distinguish the topology and the structure of various complex networks

Dianthracenylazatrioxa[8]circulene: synthesis, characterization and application in OLEDs

A soluble, green-blue fluorescent, pi-extended azatrioxa[8]circulene was synthesized by oxidative condensation of a 3,6-dihydroxycarbazole and 1,4-anthraquinone by using benzofuran scaffolding. This is the first circulene to incorporate anthracene within its carbon framework. Solvent-dependent fluorescence and bright green electroluminescence accompanied by excimer emission are the key optical properties of this material. The presence of sliding pi-stacked columns in the single crystal of dianthracenylazatrioxa[8]circulene is found to cause a very high electron-hopping rate, thus making this material a promising n-type organic semiconductor with an electron mobility predicted to be around 2.26 cm(2) V-1 s(-1). The best organic light-emitting diode (OLED) device based on the dianthracenylazatrioxa[8]circulene fluorescent emitter has a brightness of around 16 000 Cd m(-2) and an external quantum efficiency of 3.3 %. Quantum dot-based OLEDs were fabricated by using dianthracenylazatrioxa[8]circulene as a host matrix material.Peer reviewe

In vitro culture with gemcitabine augments death receptor and NKG2D ligand expression on tumour cells

Much effort has been made to try to understand the relationship between chemotherapeutic treatment of cancer and the immune system. Whereas much of that focus has been on the direct effect of chemotherapy drugs on immune cells and the release of antigens and danger signals by malignant cells killed by chemotherapy, the effect of chemotherapy on cells surviving treatment has often been overlooked. In the present study, tumour cell lines: A549 (lung), HCT116 (colon) and MCF-7 (breast), were treated with various concentrations of the chemotherapeutic drugs cyclophosphamide, gemcitabine (GEM) and oxaliplatin (OXP) for 24 hours in vitro. In line with other reports, GEM and OXP upregulated expression of the death receptor CD95 (fas) on live cells even at sub-cytotoxic concentrations. Further investigation revealed that the increase in CD95 in response to GEM sensitised the cells to fas ligand treatment, was associated with increased phosphorylation of stress activated protein kinase/c-Jun N-terminal kinase and that other death receptors and activatory immune receptors were co-ordinately upregulated with CD95 in certain cell lines. The upregulation of death receptors and NKG2D ligands together on cells after chemotherapy suggest that although the cells have survived preliminary treatment with chemotherapy they may now be more susceptible to immune cell-mediated challenge. This re-enforces the idea that chemotherapy-immunotherapy combinations may be useful clinically and has implications for the make-up and scheduling of such treatments

Vicious Walkers and Hook Young Tableaux

We consider a generalization of the vicious walker model. Using a bijection map between the path configuration of the non-intersecting random walkers and the hook Young diagram, we compute the probability concerning the number of walker's movements. Applying the saddle point method, we reveal that the scaling limit gives the Tracy--Widom distribution, which is same with the limit distribution of the largest eigenvalues of the Gaussian unitary ensemble.Comment: 23 pages, 5 figure

On the partial connection between random matrices and interacting particle systems

In the last decade there has been increasing interest in the fields of random matrices, interacting particle systems, stochastic growth models, and the connections between these areas. For instance, several objects appearing in the limit of large matrices arise also in the long time limit for interacting particles and growth models. Examples of these are the famous Tracy-Widom distribution functions and the Airy_2 process. The link is however sometimes fragile. For example, the connection between the eigenvalues in the Gaussian Orthogonal Ensembles (GOE) and growth on a flat substrate is restricted to one-point distribution, and the connection breaks down if we consider the joint distributions. In this paper we first discuss known relations between random matrices and the asymmetric exclusion process (and a 2+1 dimensional extension). Then, we show that the correlation functions of the eigenvalues of the matrix minors for beta=2 Dyson's Brownian motion have, when restricted to increasing times and decreasing matrix dimensions, the same correlation kernel as in the 2+1 dimensional interacting particle system under diffusion scaling limit. Finally, we analyze the analogous question for a diffusion on (complex) sample covariance matrices.Comment: 31 pages, LaTeX; Added a section concerning the Markov property on space-like path

Optimization of supply diversity for the self-assembly of simple objects in two and three dimensions

The field of algorithmic self-assembly is concerned with the design and analysis of self-assembly systems from a computational perspective, that is, from the perspective of mathematical problems whose study may give insight into the natural processes through which elementary objects self-assemble into more complex ones. One of the main problems of algorithmic self-assembly is the minimum tile set problem (MTSP), which asks for a collection of types of elementary objects (called tiles) to be found for the self-assembly of an object having a pre-established shape. Such a collection is to be as concise as possible, thus minimizing supply diversity, while satisfying a set of stringent constraints having to do with the termination and other properties of the self-assembly process from its tile types. We present a study of what we think is the first practical approach to MTSP. Our study starts with the introduction of an evolutionary heuristic to tackle MTSP and includes results from extensive experimentation with the heuristic on the self-assembly of simple objects in two and three dimensions. The heuristic we introduce combines classic elements from the field of evolutionary computation with a problem-specific variant of Pareto dominance into a multi-objective approach to MTSP.Comment: Minor typos correcte

On recurrence and ergodicity for geodesic flows on noncompact periodic polygonal surfaces

We study the recurrence and ergodicity for the billiard on noncompact polygonal surfaces with a free, cocompact action of $\Z$ or $\Z^2$. In the $\Z$-periodic case, we establish criteria for recurrence. In the more difficult $\Z^2$-periodic case, we establish some general results. For a particular family of $\Z^2$-periodic polygonal surfaces, known in the physics literature as the wind-tree model, assuming certain restrictions of geometric nature, we obtain the ergodic decomposition of directional billiard dynamics for a dense, countable set of directions. This is a consequence of our results on the ergodicity of \ZZ-valued cocycles over irrational rotations.Comment: 48 pages, 12 figure

Topological aggregation, the twin paradox and the No Show paradox

International audienceConsider the framework of topological aggregation introduced by Chichilnisky (1980). We prove that in this framework the Twin Paradox and the No Show Paradox cannot be avoided. Anonymity and unanimity are not needed to obtain these results

Second order analysis of geometric functionals of Boolean models

This paper presents asymptotic covariance formulae and central limit theorems for geometric functionals, including volume, surface area, and all Minkowski functionals and translation invariant Minkowski tensors as prominent examples, of stationary Boolean models. Special focus is put on the anisotropic case. In the (anisotropic) example of aligned rectangles, we provide explicit analytic formulae and compare them with simulation results. We discuss which information about the grain distribution second moments add to the mean values.Comment: Chapter of the forthcoming book "Tensor Valuations and their Applications in Stochastic Geometry and Imaging" in Lecture Notes in Mathematics edited by Markus Kiderlen and Eva B. Vedel Jensen. (The second version mainly resolves minor LaTeX problems.