276 research outputs found

    Pedotechniques strategies to improve soil resilience against the impact of irrigation by municipal wastewater: using zeolitized tuffs as soil amendments

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    A research was started aiming at evaluating the possible use of natural zeolites as exchange conditioners to improve and make durable the soil resilience against the adverse effects of the use of anomalous wastewater, for irrigation purposes. To satisfy such aims, two zeolitized tuffs (ZTs), viz. a Neapolitan yellow tuff (NYT) and a clinoptilolite bearing tuff (ZCL), were tested as pedotechnical materials to improve soil resilience against the impact of treatment by a ‘dirty’ municipal wastewater (DMW)

    Dynamic modeling of levitation of a superconducting bulk by coupled HH-magnetic field and Arbitrary Lagrangian-Eulerian formulations

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    Intrinsically stable magnetic levitation between superconductors and permanent magnets can be exploited in a variety of applications of great technical interest in the field of transportation (rail transportation), energy (flywheels) and industry. In this contribution, we present a new model for the calculation of levitation forces between superconducting bulks and permanent magnet, based on the HH-formulation of Maxwell's equations coupled with an Arbitrary Lagrangian-Eulerian formulation. The model uses a moving mesh that adapts at each time step based on the time-change of the distance between a superconductor bulk and a permanent magnet. The model is validated against a fixed mesh model (recently in turn validated against experiments) that uses an analytical approach for calculating the magnetic field generated by the moving permanent magnet. Then, it is used to analyze the magnetic field dynamics both in field-cooled and zero-field-cooled conditions and successively used to test different configurations of permanent magnets and to compare them in terms of levitation forces. The easiness of implementation of this model and its flexibility in handling different geometries, material properties, and application scenarios make the model an attractive tool for the analysis and optimization of magnetic levitation-based applications

    Zeolitized tuffs in pedotechnique for quarry restoration: evaluation of phytonutritional efficiency in ^AUP model horizons

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    A study was started aiming at assessing the suitability of zeolitized tuff as optimal mineral Human Transported Materials (HTMs) in pedotechnologies for quarry restoration

    Effects of Microencapsulated Blend of Organic Acids and Pure Botanicals on the Ruminal Microbiota in an In Vitro Dual-Flow Continuous Culture System

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    The objective of the study was to evaluate the effects of dietary supplementation of a microencapsulated blend of organic acids and pure botanicals (mOAPBs) on the solid- and liquid-associated microenvironment (SAM and LAM, respectively) of the ruminal microbiome using an in vitro dual-flow continuous culture system. Ruminal content was incubated in eight fermenters and the basal diet was supplemented with increasing levels of mOAPBs (0; 0.12; 0.24; or 0.36% DM) which contained 55.6% hydrogenated and refined palm oil, 25% citric acid, 16.7% sorbic acid, 1.7% thymol, and 1% vanillin. All diets had a similar nutritional composition (16.1 CP, 30.9 NDF, and 32.0 starch, % DM basis). After 7 days of adaptation, a pooled sample across the days was collected in each period for identification of the microbiome of SAM and LAM. There was no effect of mOAPB on alpha-, beta-diversity, and microbial abundance. The SAM had a greater bacterial diversity and the principal component analysis demonstrated that it had a divergent bacterial profile from LAM. Additionally, SAM had an increased abundance of carbohydrate-degrading microorganisms. In summary, mOAPBs did not modulate the ruminal microbiome. The microenvironment microbiome of solid- and liquid-associated microenvironments were different, with SAM having a greater carbohydrate-degrading microorganism population

    Usefulness and role of magnetic resonance imaging in a case of complete androgen insensitivity syndrome

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    AbstractComplete androgen insensitivity syndrome (CAIS) is an X-linked, recessive disorder caused by mutations of the androgen receptor (AR), in which genetic males (46,XY) show female external genitalia. Individuals with CAIS have mostly normal external genitalia, lack of Müllerian structures (Fallopian tubes, uterus, proximal portion of the vagina) and undescended testes (intra-abdominal, inguinal, or labial). Management and diagnosis of CAIS should be undertaken by a multidisciplinary team of experts in sexual development disorders. Gonadectomy represents a standard therapeutic choice to prevent testicular malignancy in the prepubertal period, with subsequent hormonal replacement therapy, or in late adolescence, after completion of pubertal development. Imaging examinations play a pivotal role in the diagnosis, assessment, and detection of the gonads before surgical treatments. Magnetic resonance imaging (MRI) is the gold standard to diagnose and locate the gonads, and to plan laparoscopic gonadectomy and gonadic surveillance, in particular in the increasingly large number of patients who decide to delay or ultimately not to undergo gonadectomy. We present a case of a 14-year-old female with primary amenorrhea

    Variability of nutrient and thermal structure in surface waters between New Zealand and Antarctica, October 2004-January 2005

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    We describe the upper ocean thermal structure and surface nutrient concentrations between New Zealand and Antarctica along five transects that cross the Subantarctic Front, the Polar Front (PF) and the southern Antarctic Circumpolar Current (ACC) front. The surface water thermal structure is coupled with variations in surface nutrient concentrations, making water masses identifiable by both temperature and nutrient ranges. In particular, a strong latitudinal gradient in orthosilicate concentration is centred at the PF. On the earlier sections that extend south-west from the Campbell Plateau, orthosilicate increases sharply southward from 10–15 to 50–55 µmol l−1 between 58° S and 60° S, while surface temperature drops from 7°C to 2°C. Nitrate increases more regularly toward the south, with concentrations ranging from 10–12 µmol l−1 at 54° S to 25–30 µmol l−1 at 66° S. The same features are observed during the later transects between New Zealand and the Ross Sea, but the sharp silica and surface temperature gradients are shifted between 60° S and 64° S. Both temporal and spatial factors may influence the observed variability. The January transect suggests an uptake of silica, orthophosphate and nitrate between 63° S and 70° S over the intervening month, with an average depletion near 37%, 44% and 29%, respectively. An N/P (nitrite + nitrate/orthophosphate) apparent drawdown ratio of 8.8±4.1 and an Si/N (silicic acid/nitrite + nitrate) apparent drawdown ratio >1 suggest this depletion results from a seasonal diatom bloom. A southward movement of the oceanic fronts between New Zealand and the Ross Sea relative to prior measurements is consistent with reports of recent warming and changes in the ACC

    STUDY OF AMORPHOUS GERMANIUM-NITROGEN ALLOYS THROUGH X-RAY PHOTOELECTRON AND AUGER ELECTRON SPECTROSCOPIES

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    In this work, experimentally determined values of electron spectroscopic shifts induced by nitrogen in Ge core levels of substoichiometric amorphous germanium-nitrogen (a-GeN) alloys are discussed and presented. X-ray photoelectron spectroscopy (XPS) and x-ray excited Auger electron spectroscopy (XAES) are employed to study the behavior of the Ge 3d and LMM spectra, respectively, and combined the corresponding XPS and Auger core levels shifts to determine Δα′, the modified Auger parameter shift, which is exempt from problems inherent in the interpretation of XPS and XAES shifts. It is demonstrated how one can use Δα′ to reliably estimate ΔnGe, the change in Ge valence charge in the alloys, and how one can calibrate XPS shifts of Si and Ge based alloys in terms of approximate values of ΔnGe

    Possible alternatives to critical elements in coatings for extreme applications

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    Surface functionalisation and protection have been used since a long time for improving specific properties of materials such as lubrication, water repellence, brightness, and for increasing durability of objects and tools. Among the different kinds of surface treatments used to achieve the required properties, the use of coatings is fundamental to guarantee substrate durability in harsh environments. Extreme working conditions of temperature, pressure, irradiation, wear and corrosion occur in several applications, thus very often requiring bulk material protection by means of coatings. In this study, three main classes of coatings used in extreme conditions are considered: i) hard and superhard coatings for application in machining tools, ii) coatings for high temperatures (thermal barrier coatings), and iii) coatings against corrosion. The presence of critical elements in such coatings (Cr, Y, W, Co, etc.) is analysed and the possibility to use CRMs-free substitutes is reviewed. The role of multilayers and nanocomposites in tailoring coating performances is also discussed for thermal barrier and superhard coatings

    A new benchmark problem for electromagnetic modelling of superconductors: the high-Tc_{c} superconducting dynamo

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    The high-Tc_{c} superconducting (HTS) dynamo is a promising device that can inject large DC supercurrents into a closed superconducting circuit. This is particularly attractive to energise HTS coils in NMR/MRI magnets and superconducting rotating machines without the need for connection to a power supply via current leads. It is only very recently that quantitatively accurate, predictive models have been developed which are capable of analysing HTS dynamos and explain their underlying physical mechanism. In this work, we propose to use the HTS dynamo as a new benchmark problem for the HTS modelling community. The benchmark geometry consists of a permanent magnet rotating past a stationary HTS coated-conductor wire in the open-circuit configuration, assuming for simplicity the 2D (infinitely long) case. Despite this geometric simplicity the solution is complex, comprising time-varying spatially-inhomogeneous currents and fields throughout the superconducting volume. In this work, this benchmark problem has been implemented using several different methods, including H-formulation-based methods, coupled H-A and T-A formulations, the Minimum Electromagnetic Entropy Production method, and integral equation and volume integral equation-based equivalent circuit methods. Each of these approaches show excellent qualitative and quantitative agreement for the open-circuit equivalent instantaneous voltage and the cumulative time-averaged equivalent voltage, as well as the current density and electric field distributions within the HTS wire at key positions during the magnet transit. Finally, a critical analysis and comparison of each of the modelling frameworks is presented, based on the following key metrics: number of mesh elements in the HTS wire, total number of mesh elements in the model, number of degrees of freedom, tolerance settings and the approximate time taken per cycle for each model. This benchmark and the results contained herein provide researchers with a suitable framework to validate, compare and optimise their own methods for modelling the HTS dynamo
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