Quantum Communication and Computing With Atomic Ensembles Using Light-Shift Imbalance Induced Blockade

Recently, we have shown that for conditions under which the so-called light-shift imbalance induced blockade (LSIIB) occurs, the collective excitation of an ensemble of a multi-level atom can be treated as a closed two level system. In this paper, we describe how such a system can be used as a quantum bit (qubit) for quantum communication and quantum computing. Specifically, we show how to realize a C-NOT gate using the collective qubit and an easily accessible ring cavity, via an extension of the so-called Pellizzari scheme. We also describe how multiple, small-scale quantum computers realized using these qubits can be linked effectively for implementing a quantum internet. We describe the details of the energy levels and transitions in 87Rb atom that could be used for implementing these schemes.Comment: 16 pages, 9 figures. Accepted in Phys. Rev.

Tunnel Probabilistic Structural Analysis Using the FORM

In this paper tunnel probabilistic structural analysis (TuPSA) was performed using the first order reliability method (FORM). In TuPSA, a tunnel performance function is defined according to the boundary between the structural stability and instability. Then the performance function is transformed from original space into the standard normal variable space to obtain the design point, reliability index, and also the probability of tunnel failure. In this method, it is possible to consider the design factors as the dependent or independent random parameters with arbitrary probability distributions. A software code is developed to perform the tunnel probabilistic structural analysis (TuPSA) using the FORM. For validation and verification of TuPSA, a typical tunnel example with random joints orientations as well as mechanical properties has been studied. The results of TuPSA were compared with those obtained from Monte-Carlo simulation. The results show, in spite of deterministic analysis which indicates that the rock blocks are stable, that TuPSA resulted in key-blocks failure with certain probabilities. Comparison between probabilistic and deterministic analyses results indicates that probabilistic results, including the design point and probability of failure, are more rational than deterministic factor of safety

Permeability Analysis based on information granulation theory

This paper describes application of information granulation theory, on the analysis of "lugeon data". In this manner, using a combining of Self Organizing Map (SOM) and Neuro-Fuzzy Inference System (NFIS), crisp and fuzzy granules are obtained. Balancing of crisp granules and sub- fuzzy granules, within non fuzzy information (initial granulation), is rendered in open-close iteration. Using two criteria, "simplicity of rules "and "suitable adaptive threshold error level", stability of algorithm is guaranteed. In other part of paper, rough set theory (RST), to approximate analysis, has been employed >.Validation of the proposed methods, on the large data set of in-situ permeability in rock masses, in the Shivashan dam, Iran, has been highlighted. By the implementation of the proposed algorithm on the lugeon data set, was proved the suggested method, relating the approximate analysis on the permeability, could be applied.Comment: 8 pages,7 figure

Soil abrasiveness for EPB-TBM along Tehran metro tunnel line 7, Iran

Full-face shielded tunnel boring machines (TBM) including earth pressure balance (EPB) shields have been used almost exclusively for soft ground tunneling because of the many advantages the offer in comparison to the conventional methods. The total number of EPB-TBMs that were utilized for tunneling between 2005 and 2010 is approximately 350 units worldwide as reported by [1]. These machines encounter a wide range of geological conditions and hazards. One of the most critical adverse conditions is encountering abrasive soils and excessive wear on the cutting tools and the cutterhead as has been reported in many EPB tunneling projects worldwide [2], [3]. Inspection and maintenance of cutting tools below the groundwater table is usually performed under hyperbaric conditions where air pressure is used to provide tunnel face stability. This involves creating a plug at the face, removing the spoils (muck), applying compressed air, and allowing the crew into the cutting chamber via an air lock. This entire process can take days to complete. Consequently, the tool inspection and maintenance in soft ground tunneling is a time consuming, risky, dangerous, and costly [4]. Abrasiveness of soil and rock is a factor with considerable influence on the wear of tools. The wear of excavation tools is an important measurable indicator of rock and soil excavation in tunnelling, in addition to the volume of material excavated (Fig. 1). [5]. In mechanized tunneling the term wear is classified into two categories, primary wear and secondary wear. Primary wear is an expected type of wear that can occur on several parts of the excavation tools, such as drag bits, disc cutters, scrapers and buckets, etc. Secondary wear, on the other hand, is an unplanned type of wear that affects the cutterhead spokes, cutter saddles, bulkheads and also much conveyance parts such as the screw conveyor. The first type of wear requires replacement at appropriate intervals whereas the second type is not and therefore the parts are not anticipated to be replaced regularly. As such the TBM performance may be affected significantly if sever secondary wear occurs [6]. In this paper, an investigation was undertaken to discern the main cause of the observed wear on EPB-TBM of Tehran Metro Line 7 (North-South lot). The wear potential of soils and rocks are assessed with respect to approach on the matter was introduced by [5] and Cerchar test, respectively

Numerical Modeling of Hydraulic Confinement around Crude Oil Storage Cavern in Fractured Rocks: Direct Application of DFN Concept

Unlined rock caverns for hydrocarbon storage are mainly excavated in strong and stable rock masses with very low-permeable matrix, where hydrocarbon migration is only possible along fractures connected to the cavern boundaries and their networks. In this paper, the hydraulic confinement around a URC cavern was simulated by directly applying distinct fracture network (DFN) model. First, a computational code, so-called “FNETF”, was developed to generate DFN and solving fluid flow equation along fractures. Proper internal hydraulic boundary condition of water-hydrocarbon interface at cavern boundary was defined based on the fluids properties and applied in the FNETF code. Fluid flow in fracture network was numerically simulated for different outer boundary hydraulic conditions assigned by different groundwater pressures of water curtain. Finally, the assessment achieved to expect the occurrence of hydrocarbon