Constructing a statistical mechanics for Beck-Cohen superstatistics

The basic aspects of both Boltzmann-Gibbs (BG) and nonextensive statistical mechanics can be seen through three different stages. First, the proposal of an entropic functional ($S_{BG} =-k\sum_i p_i \ln p_i$ for the BG formalism) with the appropriate constraints ($\sum_i p_i=1$ and $\sum_i p_i E_i = U$ for the BG canonical ensemble). Second, through optimization, the equilibrium or stationary-state distribution ($p_i = e^{-\beta E_i}/Z_{BG}$ with $Z_{BG}=\sum_j e^{-\beta E_j}$ for BG). Third, the connection to thermodynamics (e.g., $F_{BG}= -\frac{1}{\beta}\ln Z_{BG}$ and $U_{BG}=-\frac{\partial}{\partial \beta} \ln Z_{BG}$). Assuming temperature fluctuations, Beck and Cohen recently proposed a generalized Boltzmann factor $B(E) = \int_0^\infty d\beta f(\beta) e^{-\beta E}$. This corresponds to the second stage above described. In this letter we solve the corresponding first stage, i.e., we present an entropic functional and its associated constraints which lead precisely to $B(E)$. We illustrate with all six admissible examples given by Beck and Cohen.Comment: 3 PS figure

Generalizing the Planck distribution

Along the lines of nonextensive statistical mechanics, based on the entropy $S_q = k(1- \sum_i p_i^q)/(q-1) (S_1=-k \sum_i p_i \ln p_i)$, and Beck-Cohen superstatistics, we heuristically generalize Planck's statistical law for the black-body radiation. The procedure is based on the discussion of the differential equation $dy/dx=-a_{1}y-(a_{q}-a_{1}) y^{q}$ (with $y(0)=1$), whose $q=2$ particular case leads to the celebrated law, as originally shown by Planck himself in his October 1900 paper. Although the present generalization is mathematically simple and elegant, we have unfortunately no physical application of it at the present moment. It opens nevertheless the door to a type of approach that might be of some interest in more complex, possibly out-of-equilibrium, phenomena.Comment: 6 pages, including 2 figures. To appear in {\it Complexity, Metastability and Nonextensivity}, Proc. 31st Workshop of the International School of Solid State Physics (20-26 July 2004, Erice-Italy), eds. C. Beck, A. Rapisarda and C. Tsallis (World Scientific, Singapore, 2005

Yeasts

Yeasts are a group of eukaryotic microfungi with a well-defined cell wall whose growth is either entirely unicellular or a combination of hyphal and unicellular reproduction. The approximately 1500 known yeast species belong to two distinct fungal phyla, the Ascomycota and the Basidiomycota. Within each these phyla, yeasts can be found in several subphyla or classes, reflecting the enormous diversity of their evolutionary origins and biochemical properties. In nature, yeasts are found mainly in association with plants or animals but are also present in soil and aquatic environments. Yeasts grow rapidly and have simple nutritional requirements, for which reason they have been used as model systems in biochemistry, genetics and molecular biology. They were the first microorganisms to be domesticated for the production of beer, bread or wine, and they continue to be used for the benefit of humanity in the production of many important health care and industrial commodities, including recombinant proteins, biopharmaceuticals, biocontrol agents and biofuels. The best-known yeast is the species Saccharomyces cerevisiae, which may be regarded as the world’s foremost industrial microbe

ANALISA KEANDALAN SISTEM DISTRIBUSI 20 kV PADA PENYULANG PT. PLN (PERSERO) ULP TANJUNG MENGGUNAKAN METODE SECTION TECHNIQUE-RIA

Resilience and reliability in distributing electricity is crucial and needs to always be maintained in order to meet consumer needs. Several aspects that indicate the reliability of an electricity distribution system include the continuity of the available energy supply for 24 hours accurately In evaluating the reliability of distribution networks, several indicators are used. One of them is SAIFI (System Average Interruption Frequency index), which is used as a reliability indicator based on the number of disturbances that occur on average over 12 months. Then, SAIDI (System Average Interruption Duration Index) becomes an indicator that measures the duration of interruptions experienced by customers during a 12 month period. Meanwhile, CAIDI (Customer Average Interruption Duration Index) is an index that measures the average duration of disruption experienced by consumers over 12 months. Calculation results using the SECTION TECHNIQUE-RIA method for the SLG 04 feeder, where this index value was obtained using Microsoft Excel software. SAIDI is 0.7 times/customer/year while the SAIFI index value is 1.9 hours/customer/year. Then the CAIDI index value is 1.3. The results obtained through MATLAB are the SAIDI reliability index of 0.9 times/customer/year and SAIFI of 2.0 hours/customer/year, and CAIDI 1.3 hours/customer

Cloaking and anamorphism for light and mass diffusion

We first review classical results on cloaking and mirage effects for electromagnetic waves. We then show that transformation optics allows the masking of objects or produces mirages in diffusive regimes. In order to achieve this, we consider the equation for diffusive photon density in transformed coordinates, which is valid for diffusive light in scattering media. More precisely, generalizing transformations for star domains introduced in [Diatta and Guenneau, J. Opt. 13, 024012, 2011] for matter waves, we numerically demonstrate that infinite conducting objects of different shapes scatter diffusive light in exactly the same way. We also propose a design of external light-diffusion cloak with spatially varying sign-shifting parameters that hides a finite size scatterer outside the cloak. We next analyse non-physical parameter in the transformed Fick's equation derived in [Guenneau and Puvirajesinghe, R. Soc. Interface 10, 20130106, 2013], and propose to use a non-linear transform that overcomes this problem. We finally investigate other form invariant transformed diffusion-like equations in the time domain, and touch upon conformal mappings and non-Euclidean cloaking applied to diffusion processes.Comment: 42 pages, Latex, 14 figures. V2: Major changes : some formulas corrected, some extra cases added, overall length extended from 21 pages (V1) to 42 pages (present version V2). The last version will appear at Journal of Optic

Wheat response to CO2 enrichment: CO2 exchanges transpiration and mineral uptakes

When simulating canopies planted in varied densities, researchers were able to demonstrate that increase of dry matter production by enhancing CO2 quickly becomes independant of increase of leaf area, especially above leaf area index of 2; dry matter gain results mainly from photosynthesis stimulation per unit of surface (primary CO2 effect). When crop density is low (the plants remaining alone a longer time), the effects of increasing leaf surface (tillering, leaf elongation here, branching for other plants etc.) was noticeable and dry matter simulation factor reached 1.65. This area effect decreased when canopy was closed in, as the effect of different surfaces no longer worked. The stimulation of photosynthesis reached to the primary CO2 effect. The accumulation in dry matter which was fast during that phase made the original weight advantage more and more neglectible. Comparison with short term measurements showed that first order long term effect of CO2 in wheat is predictible with short term experiment, from the effect of CO2 on photosynthesis measured on reference sample