Probability and Thermodynamics

When P indistinguishable balls are randomly distributed among L distinguishable boxes, and considering the dense system , our natural intuition tells us that the box with the average number of balls P/L has the highest probability and that none of boxes are empty; however in reality, the probability of the empty box is always the highest. This fact is with contradistinction to sparse system (i.e. energy distribution in gas) in which the average value has the highest probability. Here we show that when we postulate the requirement that all possible configurations of balls in the boxes have equal probabilities, a realistic “long tail” distribution is obtained. This formalism when applied for sparse systems converges to distributions in which the average is preferred. We calculate some of the distributions resulted from this postulate and obtain most of the known distributions in nature, namely: Zipf’s law, Benford’s law, particles energy distributions, and more. Further generalization of this novel approach yields not only much better predictions for elections, polls, market share distribution among competing companies and so forth, but also a compelling probabilistic explanation for Planck’s famous empirical finding that the energy of a photon is hv.

Natural Gas production and distribution network plans are one of the most common ways to increase energy consumption efficiency. Due to the uncertainty of the economic parameters, the economic justification of this system is very difficult. In this research, the economic risk of investing in urban gas distribution systems has been done with the analytical hierarchy process (AHP). With the development and condensation of urban gas supply networks, accidents caused by gas leaks and other external factors have also increased. Therefore, in recent years, the issue of safety and risk analysis of urban gas networks has received special attention from responsible companies and other urban and safety experts. Gas distribution lines often pass in the vicinity of crowded areas and buildings, so any accident for these lines will lead to a lot of human and financial losses. In the present study, in order to improve the gas supply situation and reduce the risk of failure in Indonesia, urban gas pipelines have been studied to reduce the costs. In this paper, multi-criteria decision making method analysis is used to identify and evaluate the hazards of urban gas pipelines and the risk of occurrence of each hazard is calculated. There was a meaningful relationship based on economic-financial theories between economic factors and investment risk in the gas industry, which emphasizes the greater and more significant effect of exchange rate, failures and inflation rate variables in comparison with other research variables in the matter of controlling investment risk in the gas industry. The effects of changes in energy prices and the economic environment in explaining the behavior of investment risk in this industry have placed the next level of importance. The results showed that with the increase in energy prices, the economics of gas production and distribution risk management plans have improved and the regular trend of energy price increases can guarantee the profitability of fuel consumption optimization plans.

The Natural Gas Transmission and Distribution Model (NGTDM) is a component of the National Energy Modeling System (NEMS) used to represent the domestic natural gas transmission and distribution system. NEMS is the third in a series of computer-based, midterm energy modeling systems used since 1974 by the Energy Information Administration (EIA) and its predecessor, the Federal Energy Administration, to analyze domestic energy-economy markets and develop projections. This report documents the archived version of NGTDM that was used to produce the natural gas forecasts used in support of the Annual Energy Outlook 1994, DOE/EIA-0383(94). The purpose of this report is to provide a reference document for model analysts, users, and the public that defines the objectives of the model, describes its basic design, provides detail on the methodology employed, and describes the model inputs, outputs, and key assumptions. It is intended to fulfill the legal obligation of the EIA to provide adequate documentation in support of its models (Public Law 94-385, Section 57.b.2). This report represents Volume 1 of a two-volume set. (Volume 2 will report on model performance, detailing convergence criteria and properties, results of sensitivity testing, comparison of model outputs with the literature and/or other model results, and major unresolved issues.) Subsequent chapters of this report provide: (1) an overview of the NGTDM (Chapter 2); (2) a description of the interface between the National Energy Modeling System (NEMS) and the NGTDM (Chapter 3); (3) an overview of the solution methodology of the NGTDM (Chapter 4); (4) the solution methodology for the Annual Flow Module (Chapter 5); (5) the solution methodology for the Distributor Tariff Module (Chapter 6); (6) the solution methodology for the Capacity Expansion Module (Chapter 7); (7) the solution methodology for the Pipeline Tariff Module (Chapter 8); and (8) a description of model assumptions, inputs, and outputs (Chapter 9).

The new generation radio telescopes, such as the Square Kilometre Array (SKA) currently under construction, will use aperture array, technology for the low frequency regime. For SKA2, the second phase scheduled after the realization of SKA1, aperture array technology is proposed up to 1.4 GHz. The antenna element count, as well as the signal processing cost, of such a system will be high. In this paper we analyze an option to reduce the number of antenna elements by making the array sparse. To reduce the signal processing cost Fast Fourier Transform Beamforming is proposed and it performance is compared to traditional beamforming. To guide the system design a Figure of Merit for the performance cost ratio is proposed and evaluated for various levels of sparsity of the antenna array. It is concluded that, for equal front-end and back-end costs, a sparse system is only marginally better than a dense system. Only when signal processing cost is significantly lower than the front-end hardware, a sparse system can be competitive.

We focus on the problem of computing approximate Nash equilibria and well-supported approximate Nash equilibria in random bimatrix games, where each player's payoffs are bounded and independent random variables, not necessarily identically distributed, but with common expectations. We show that the completely mixed uniform strategy profile, i.e. the combination of mixed strategies (one per player) where each player plays with equal probability each one of her available pure strategies, is with high probability a √ln n/n -Nash equilibrium and a √3 lnn/n -well supported Nash equilibrium, where n is the number of pure strategies available to each player. This asserts that the completely mixed, uniform strategy profile is an almost Nash equilibrium for random bimatrix games, since it is, with high probability, an e-well-supported Nash equilibrium where e tends to zero as n tends to infinity.

The Natural Gas Transmission and Distribution Model (NGTDM) of the National Energy Modeling System is developed and maintained by the Energy Information Administration (EIA), Office of Integrated Analysis and Forecasting. This report documents the archived version of the NGTDM that was used to produce the natural gas forecasts presented in the Annual Energy Outlook 1996, (DOE/EIA-0383(96)). The purpose of this report is to provide a reference document for model analysts, users, and the public that defines the objectives of the model, describes its basic approach, and provides detail on the methodology employed. Previously this report represented Volume I of a two-volume set. Volume II reported on model performance, detailing convergence criteria and properties, results of sensitivity testing, comparison of model outputs with the literature and/or other model results, and major unresolved issues.

The work defines the philosophy of COMOTI – Romanian Research & Development Institute for Gas Turbines, in the predictability of intervention time in case of defects, respectively the reduction of the cost price of maintenance for its MOVs (Motor Operated Valves), used on its own equipments for natural gas compression, existing in the natural gas compression and distribution sites from Romania. In the present work, the emphasis is on operational reliability and mentability, which are capitalized on the basis of the results regarding the operating behavior, over a certain period of time, of a large number of identical types of MOVs, actually used by the beneficiaries.

The present paper presents the development effort and pre-commercial deployment of Explorer II — a semi-autonomous, self-powered, tetherless robotic platform, carrying a Remote Field Eddy Current (RFEC) sensor, for the inspection of unpiggable natural gas transmission and distribution pipelines in the 6 to 8 inch (152 to 203 mm) range, including those that feature multiple diameters, short radius and mitered bends, and tees. The system is based on a modular design that allows the system to be deployed in various configurations to carry out visual inspection and/or non-destructive evaluation (NDE) of a pipeline. The heart of this system is a RFEC sensor able to measure the pipeline’s wall thickness. In addition, two fisheye cameras at each end of the robot provide high quality visual inspection capabilities for locating joints, tee-offs, and other pipeline features. The system can operate, including launching and retrieval, in live pipelines with pressures up to 750 psig (50 bars). The system is currently being offered for pre-commercial deployments and is expected to be commercially available in the Fall of 2010.

Introduction. Tariffing as a process is complex and important, especially to ensure an adequate level of energy security and competitive balance amongst its participants at all levels. Therefore, it is important to follow the rules when setting tariffs in any sector or region: methodological approaches to calculating future tariffs should be readily accessible; tariffs should be easy to implement; future costs should be secured in such a way as to prevent possible shortcomings in the decision-making process; in order to develop the networks themselves and to use them effectively, as far as possible, the tariffs paid by their users should fully reflect the costs they incur in the system. The purpose is a comprehensive study of methodological and practical approaches to calculating regional tariffs for natural gas transportation and distribution services. The methodology of the investigated problems includes the systematic scientific methods of cognition, namely: analysis, synthesis, critical thinking, empiricism and modeling of a possible scenario. Results. Therefore, as a result of the study of methodological and practical approaches to the regional tariffs calculation for gas transportation and distribution services, it was determined that this process is fraught with certain difficulties and is particularly important for ensuring an adequate level of energy security and competitive balance among its participants at all levels. Conclusion. As a consequence, when setting tariffs in any sector or region, it is important to adhere to the following principles: transparency, simplicity, avoidance of possible distortion, predictability, value reflection, non-discrimination, cost recovery. Key words: distribution, transportation, natural gas, region, distribution of natural gas, method of calculation of tariff formation, gas distribution company.

The primary natural gas industry is made up of three main activities: extraction, transportation, and distribution. Natural gas transportation and distribution prices are regulated in Peru. Natural gas transportation is regulated by the efficient model company method and the distribution of natural gas is regulated by the efficient model company method, but assigning proportional prices for each use (electricity generation, industry, vehicle use and domestic consumption). to the alternates. This study compares the natural gas distribution prices determined in Peru with those that would be obtained under the efficient company model with price allocation proportional to costs. The economic effects and the recommendations are presented as conclusions.

Context. Transition disks have dust-depleted inner regions and may represent an intermediate step of an on-going disk dispersal process, where planet formation is probably in progress. Recent millimetre observations of transition disks reveal radially and azimuthally asymmetric structures, where micron- and millimetre-sized dust particles may not spatially coexist. These properties can be the result of particle trapping and grain growth in pressure bumps originating from the disk interaction with a planetary companion. The multiple features observed in some transition disks, such as SR 21, suggest the presence of more than one planet. Aims. We aim to study the gas and dust distributions of a disk hosting two massive planets as a function of different disk and dust parameters. Observational signatures, such as spectral energy distributions, sub-millimetre, and polarised images, are simulated for various parameters. Methods. Two dimensional hydrodynamical and one dimensional dust evolution numerical simulations are performed for a disk interacting with two massive planets. Adopting the previously determined dust distribution, and assuming an axisymmetric disk model, radiative transfer simulations are used to produce spectral energy distributions and synthetic images in polarised intensity at 1.6 μm and sub-millimetre wavelengths (850 μm). We analyse possible scenarios that can lead to gas azimuthal asymmetries. Results. We confirm that planets can lead to particle trapping, although for a disk with high viscosity (αturb = 10-2), the planet should be more massive than 5 MJup and dust fragmentation should occur with low efficiency (vf ~ 30 m s-1). This will lead to a ring-like feature as observed in transition disks in the millimetre. When trapping occurs, we find that a smooth distribution of micron-sized grains throughout the disk, sometimes observed in scattered light, can only happen if the combination of planet mass and turbulence is such that small grains are not fully filtered out. A high disk viscosity (αturb = 10-2) ensures a replenishment of the cavity in micron-sized dust, while for lower viscosity (αturb = 10-3), the planet mass is constrained to be less than 5 MJup. In these cases, the gas distribution is likely to show low-amplitude azimuthal asymmetries caused by disk eccentricity rather than by long-lived vortices.

Progressing from folding trajectories to transition state ensemble in proteins

Let T n ( x ) = Σ n j =1 ± e 2π ij 2 x where ± stands for a random choice of sign with equal probability. It is shown here that with high probability min x ε[0,1) | T n ( x )| < n -σ provided n is large and σ < 1/12. Similar results are proved for other powers than squares. The problem of determining the optimal σ is open. For the case T n ( x )= Σ n j =1 r j e 2π ij d x , where d = 2, 3,... is fixed and with standard normal r j we show that the minima are typically on the order of n - d +½ with high probability and for large n .

Coupling of CFD-DEM and reaction model for 3D fluidized beds

Pipeline durability and integrity issues at hydrogen transport via natural gas distribution network