Gray wolf optimizer with bubble-net predation for modeling FCCU main fractionator

FCCU main fractionator is a complex system with multivariable, nonlinear and uncertainty. Its modeling is a hard nut to crack. In this work, the gray wolf optimization with bubble-net predation (GWO_BP) is proposed for solving this complex optimization problem. In order to enhance the global search ability and accelerate the convergence speed, the bubble-net predation of whale search scheme is applied to update the head wolf position. And the improved Lé vy flight is used to update the positions of wolfpack for overcoming the disadvantage of easily falling into local optimum. The GWO_BP is compared with basic GWO, PSO with some typical test functions and the parameter estimation of FCCU main fractionation model. The experiment results show the effectiveness of the GWO_BP.

Model and optimal operational windows for hydrodynamic fiber fractionation

Based on fitted experimental data, an empirical fractionation model for mini-channel hydrodynamic fiber fractionation (miniFrac) is presented. This model, combined with an optimization procedure, is then used as a design tool to synergize competing fractionation performance characteristics, i. e., product quality, product yield and energy demand. Based on this model, miniFrac is compared to state-of-the-art fiber fractionation technology with respect to (i) long fiber-short fiber fractionation and (ii) fines-fiber fractionation. In terms of fines-fiber fractionation, miniFrac is outperformed by typical micro-hole pressure screening regarding the purity of fines fraction. However, a comparison with a slotted (slot width of 0.2 mm) and a smooth-holed pressure screen (hole diameter of 0.8 mm) shows, that miniFrac is capable of outperforming both systems regarding product quality and energy demand at a comparable product yield. If, in the case of fines-fiber fractionation, reject purity (i. e., fines exclusion) is more important than fines purity (i. e., long fiber remain in the reject), miniFrac is an interesting tool with some key advantages over pressure screens.

Triple iron isotope constraints on the role of ocean iron sinks in early atmospheric oxygenation

The role that iron played in the oxygenation of Earth’s surface is equivocal. Iron could have consumed molecular oxygen when Fe3+-oxyhydroxides formed in the oceans, or it could have promoted atmospheric oxidation by means of pyrite burial. Through high-precision iron isotopic measurements of Archean-Paleoproterozoic sediments and laboratory grown pyrites, we show that the triple iron isotopic composition of Neoarchean-Paleoproterozoic pyrites requires both extensive marine iron oxidation and sulfide-limited pyritization. Using an isotopic fractionation model informed by these data, we constrain the relative sizes of sedimentary Fe3+-oxyhydroxide and pyrite sinks for Neoarchean marine iron. We show that pyrite burial could have resulted in molecular oxygen export exceeding local Fe2+ oxidation sinks, thereby contributing to early episodes of transient oxygenation of Archean surface environments.

Géochimie des muscovites comme indicateur du fractionnement des pegmatites de la région de Kabarore-Mparamirundi (nord-ouest du Burundi, Afrique centrale) [Geochemical signature of muscovites as pathfinder for fractionation of pegmatites in the Kabarore-Mparamirundi area (northwestern Burundi, Central Africa)]

The Kabarore-Mparamirundi area hosts numerous pegmatites spatiotemporally related to leucogranites dated at 986 ± 10 Ma in Karagwe-Ankole belt. The deposits are intensively exploited for columbite-tantalite and cassiterite. Alkali metals in muscovite (Rb 370–7590 ppm, Cs 8–1470 ppm) are modeled by Rayleigh fractional crystallization from a parental leucogranitic composition (K 4.1 wt%, Rb 321 ppm and Cs 9 ppm). The power law declining behavior of the ratio K/Rb versus Cs indicates the Rayleigh fractional crystallization as the main process of differentiation of the various pegmatite facies. Moreover, the continuous trend from granite to the most evolved, exploited pegmatites demonstrates a co-genetic link among them. The fractionation model shows that unmined and abandoned pegmatites are less fractionated (less than 94% of fractionation) while mined pegmatites are highly fractionated and constitute fractionated products of more than 94% of the initial leucogranite composition. The Rb, Cs, Ta, Sn and Li elements in muscovite can be used as a valuable tool in the exploration of fertile and sterile pegmatites in this area.

Enrichment of manganese to spessartine saturation in granite-pegmatite systems

The enrichment of manganese in peraluminous (S-type) granitic melts beginning with the anatexis of metapelitic rock and ending with the crystallization of highly evolved pegmatites is explained using experimentally derived mineral-melt partition coefficients and solubility data for Mn-rich garnet. Mineral-melt partition coefficients for Fe, Mg, and Mn between garnet, cordierite, tourmaline, and peraluminous, B-bearing hydrous granitic melt were measured between 650 and 850 °C at 200 MPaH2O. The compositions of garnet and tourmaline synthesized in these experiments are similar to those found in nature. Garnets evolve from Sps51Alm23Prp25 to Sps81Alm15Prp4 with decreasing temperature. The Mn content of cordierite increases with decreasing temperature. The composition of tourmaline does not vary with temperature. Partition coefficients, DMα/L, and exchange coefficients, KDα/L=DMα/L/DNα/L where α is a mineral, L is liquid (melt), and M and N are different elements, are presented for mineral-glass pairs. Partition coefficients for Mg, Fe, and Mn increase with decreasing temperature for garnet, tourmaline, and cordierite. The precipitation of garnet alone results in a progressive increase of MgO/FeO and a decrease of MnO/FeO in the melt. Crystallization of cordierite and tourmaline results in a decrease of MgO/FeO and an increase of MnO/FeO in melt. Tourmaline is most efficient at concentrating Mn in residual liquids. The trend toward increasing Mn/Fe in natural garnets in granites and pegmatites is not controlled by garnet itself, but instead by the crystallization of other mafic minerals in which Mg and Fe are more compatible than is Mn. A Rayleigh fractionation model constitutes a test of the partition coefficients reported in this manuscript. The starting composition for the model is that of a liquid (melt inclusions) from an anatectic S-type source. Normative modes of cordierite and biotite are calculated from that composition and are similar to modes of these minerals in natural occurrences. The model consists of crystallization of a cordierite-biotite granite from 850 to 650 °C. The model predicts that ~95% crystallization of the starting composition is required to reach saturation in spessartine-rich garnet at near-solidus temperatures. The model, therefore, is consistent with the occurrence of spessartine as restricted to highly fractionated granite-pegmatite systems at the end stages of magmatism.

Methodological approaches to prevention of radiation-induced skin reactions in neutron-photon therapy for malignant neoplasms

The goal of radiotherapy is to maximize the radiation dose to abnormal cancer cells while preventing damage to healthy tissue. in neutron therapy, the optimum regime of treatment is uncertain to date.The purpose of the study to develop a set of methodological approaches that ensure the permissible frequency and severity of radiation-induced reactions in cancer patients subjected to neutron and neutron-photon therapy (NFt) using u-120 cyclotron.Material and methods. We used the dependence of the relative biological effectiveness (RBE) of neutrons on the dose and time-dose-fractionation model (tdF). the interaction of neutrons with various types of tissues was analyzed, and the algorithm for summing neutron and photon doses in neutronphoton therapy was developed.Results. Clinical studies of neutron-photon therapy showed that the developed approaches can predict and prevent serious damage to normal tissue with a satisfactory accuracy. the role of all factors influencing the nature of radiation reactions was taken into account in the computer program, which allowed the main characteristics of the planned courses of neutron-photon therapy to be obtained.

Estimates of land and sea moisture contributions to the monsoonal rain over Kolkata, deduced based on isotopic analysis of rainwater

Moisture sources responsible for rains over Kolkata during the summer monsoon can be traced using backward air-mass trajectory analysis. A summary of such trajectories between June and September suggest that these moisture parcels originate from the Arabian Sea and travel over the dry continental region and over the Bay of Bengal (BoB) prior to their arrival at Kolkata. We use monthly satellite and ground-based observations of the hydrometeorological variables together with isotopic data of rainwater from Bangalore and Kakinada to quantify the contributions of advected continental and oceanic water vapour in the Kolkata rains. The vapour mass is modified during its transit from its original isotopic value due to addition of evaporated moisture from the BoB, and further modification occurs due to the process of rainout during transport. The evaporated component is estimated using the Craig–Gordon equation. The rainout process is simulated using a Rayleigh fractionation model. In this simulation we assume that the initial isotopic composition of vapour originating from the continent is similar to the rainwater composition measured at Bangalore. In order to explain the monthly isotopic composition in southwest monsoon rainwater at Kolkata, we invoke 65–75 % moisture contribution from the BoB; the remaining moisture is from the continental land mass.