Analysis of generalized negative binomial distributions attached to hyperbolic Landau levels

To each hyperbolic Landau level of the Poincar\'e disc is attached a generalized negative binomial distribution. In this paper, we compute the moment generating function of this distribution and supply its decomposition as a perturbation of the negative binomial distribution by a finitely-supported measure. Using the Mandel parameter, we also discuss the nonclassical nature of the associated coherent states. Next, we determine the L\'evy-Kintchine decomposition its characteristic function when the latter does not vanish and deduce that it is quasi-infinitely divisible except for the lowest hyperbolic Landau level corresponding to the negative binomial distribution. By considering the total variation of the obtained quasi-L\'evy measure, we introduce a new infinitely-divisible distribution for which we derive the characteristic function

Durability of magnesium potassium phosphate cements (MKPCs) under chemical attack

Magnesium phosphate cements (MPCs), also known as chemically bonded ceramics, represent a class of inorganic cements that have garnered considerable interest in recent years for their exceptional properties and diverse applications in the construction and engineering sectors. However, the development of these cements is relatively recent (they emerged at the beginning of the 20th century), so there are still certain aspects relating to their durability that need to be evaluated. The present work analyses the chemical durability of magnesium potassium phosphate cements (MKPCs) during 1 year of immersion in three leaching media: seawater, a Na2SO4 solution (4% by mass) and deionized water. For this, pastes of prismatic specimens of MKPC, prepared with different M/P ratio (2 and 3), were submitted to the different chemical attacks. At different ages, the changes on the mechanical strengths, microstructure (BSEM, MIP) and mineralogy (XRD, FTIR, TG/DTG) were evaluated. The results obtained indicate that, in general terms, MKPC systems show good behavior in the three media, with the more resistant system being the one prepared with a M/P molar ratio of 3

Esquistos bituminosos como materia prima alternative en la fabricación de clínker de cemento Portland. Reacciones de clinkerización y caracterización del clínker

For some time the cement industry has been seeking procedures to effectively lower the higher energy costs involved in cement manufacture. Timahdit oil shale and Jerada coal waste could potentially be used as alternative raw materials to produce clinker. This study explored the possibility of applying those materials to a greener use, based on the reactivity and burnability of raw mixes containing Moroccan oil shale and coal waste. The findings showed that, irrespective of particle size, oil shale mixes delivered higher reactivity than coal waste materials, although reactivity was highest in the oil shale clinker with a particle size 70 %).La industria cementerabusca desde hace algún tiempo procedimientos que reduzcan el alto consumo de energía de la producción de cemento. La pizarra bituminosa de Timahdit (BOS) y los desechos de carbón de Jerada (CW) se pueden utilizar potencialmente como materiales alternativos en la fabricación de clinker. Este estudio se enfoca en evaluar esta posibilidad, valorizar dichos materiales y considerar un uso más ecológico para ellos. Exploramos la reactividad y la aptitud a la cocción de mezclas crudas de clínker que contienen BOS o CW. La reactividad de los crudos que contienen BOS es mejor que la de los que contienen CW, independientemente de su tamaño de partícula, siendo el que contiene BOS con un tamaño de partícula 70%

Characterization and hydration of cements and pastes obtained from raw mix containing Moroccan oil shale and coal waste as a raw material

In the present work, the hydration and physical properties of cements obtained from a raw mixes containing oil shale and coal waste as an alternative raw material were explored. A study of clinkers was carried out using chemical analysis and Rietveld analysis and the hydrated products were characterized by conduction calorimetry, X-ray diffraction, FTIR, Differential thermal analysis-thermal gravimetry and Scanning electron microscope. The findings showed that the cement paste containing both oil shale and coal waste had the highest compressive strength. According to the hydration studies, the four hydration steps were observed in all cements. The conduction calorimetry study showed the formation of the calcium monosulfoaluminate phase (AFm) in all cements which in cement containing coal waste was retarded by 50 h due to the high Na2O concentration in its clinker. Further, the identified hydration products: C-S-H gel, portlandite and Afm phase, which detected by XRD, FTIR and ATD/TG have been observed morphologically in SEM images. Moreover, the EDX microstructural study revealed that C-S-H gel contains a less amount of Aluminum and sulfur.This paper has been carried out as part of a CSIC-Mohammed V University of Rabat, cooperation programm (iCOOPA20067). Facilities given by IETcc (CSIC) and funding from BIA 2013-47876-C2-1-P and BIA BIA2013-43293-R projects as well as the Regional Government of Madrid Community and European Social Fund (Geomaterials Programme2 S2013/MIT-2914) are gratefully acknowledged.Peer reviewe

Ecofriendly bricks elaborated from coal waste of Moroccan Jerrada Mining

Solid waste generated during mining is one of the major environmental problems associated with this industrial activity. The best solution to overcome the environmental impact of this waste is to find recycling facilities in mass-produced products that can absorb the large quantities of these available byproducts. The present study shows the feasibility of using the coal waste of Moroccan Jerrada mining in the production of ecological brick. The first step consists of consecutive stages of crushing, grinding and heating at 650°C of the coal waste with a small amount of lime in order to promote the reactive products of elaborated binders. The second step of the process consists of mixing treated coal waste with a small amount of marble dust, sand, gravel, and water, then pressed and dried at room temperature to manufacture a laboratory ecofriendly bricks. The mechanical strength and thermal conductivity are investigated

Ecofriendly bricks elaborated from coal waste of Moroccan Jerrada Mining

Solid waste generated during mining is one of the major environmental problems associated with this industrial activity. The best solution to overcome the environmental impact of this waste is to find recycling facilities in mass-produced products that can absorb the large quantities of these available byproducts. The present study shows the feasibility of using the coal waste of Moroccan Jerrada mining in the production of ecological brick. The first step consists of consecutive stages of crushing, grinding and heating at 650°C of the coal waste with a small amount of lime in order to promote the reactive products of elaborated binders. The second step of the process consists of mixing treated coal waste with a small amount of marble dust, sand, gravel, and water, then pressed and dried at room temperature to manufacture a laboratory ecofriendly bricks. The mechanical strength and thermal conductivity are investigated

Formation of Csingle bondSsingle bondH and Msingle bondSsingle bondH gels in alkali-activated materials based on marl by-products from phosphate mines

Marls present high volume of phosphate waste rocks that are chemically inert, but their disposal creates diverse environmental issues. This study aims to evaluate the reuse of white marls from phosphate mines as a precursor to produce Alkali-Activated Materials (AAM). White marls containing palygorskite clay were calcined up to 850 °C. The alkali activation process involved the use of calcined marls (as a precursor) and NaOH:NaSiO as activators. Marls features were identified by X-ray Diffraction, X-ray Fluorescence, Fourier-transform infrared spectroscopy and Thermo-gravimetric analysis. In addition, the dissolution of Al and Si species from the marl was studied for different Sodium hydroxide concentrations and calcination temperatures. Furthermore, the compressive strength of elaborated AAM was measured, and selected samples were characterized using several methods including Solid-state Si – Al Nuclear Magnetic Resonance spectroscopy and Scanning Electron Microscopy. The XRD and NMR results indicated the co-precipitation of C[sbnd]S[sbnd]H and M[sbnd]S[sbnd]H with the presence of low amount of C/N-(A)-S[sbnd]H explained by the content of aluminum in marl. This result was confirmed by EDX and FTIR analysis. While the optimum compressive strength of 38 MPa was obtained for AAM based on calcined marl at 750 °C. This study results revealed that marls waste rocks could be used as a precursor for the formulation of AAM in construction applications