Spectral electron energy map of electron impact induced emission of nitrogen

The processes of electron impact induced fluorescence of nitrogen were studied in the electron energy range from 6 to 100 eV and in the spectral range from 330 to 1030 nm. Using the new CCD camera a Spectral Electron Energy Map of N2 was obtained. This type of data for such a wide spectral and energy range are published for the first time. The most intensive molecular emission bands were neutral nitrogen First positive system N2 (B3Πg − A3∑u+) and Second positive system N2 (C3Πu − B3Πg), First negative system N2+ (B2∑u+  − X2∑g+) and Meinel system N2+ (A2Πu − X2∑g+). The detected lower intensity transitions were Gaydon-Herman singlet system N2 (1Σu+  − a1Πg / 1Πu+  − a1Πg) and Gaydon-Green system N2 (H3Φu − G3Δg). In addition, processes of dissociative excitation and ionisation were observed, resulting in the photon emission from the neutral and singly ionised nitrogen atoms. The provided Spectral Electron Energy Map allows extraction of (i) electron energy resolved emission spectra of N2 and determination of the absolute values of excitation-emission cross sections, (ii) excitation-emission functions for any of the molecular bands or atomic lines present in the spectra

The Fluidity of Al-Si Alloy: Computer Simulation of the Influence of Temperature, Composition, and Pouring Speed

The purpose of this study is to identify relationships between the values of the fluidity obtained by computer simulation and by an experimental test in the horizontal three-channel mould designed in accordance with the Measurement Systems Analysis. Al-Si alloy was a model material. The factors affecting the fluidity varied in following ranges: Si content 5 wt.% – 12 wt.%, Fe content 0.15 wt.% – 0.3 wt. %, the pouring temperature 605°C-830°C, and the pouring speed 100 g · s-1 – 400 g · s-1. The software NovaFlow&Solid was used for simulations. The statistically significant difference between the value of fluidity calculated by the equation and obtained by experiment was not found. This design simplifies the calculation of the capability of the measurement process of the fluidity with full replacement of experiments by calculation, using regression equation

MONUMENT DAMAGE INFORMATION SYSTEM (MONDIS): AN ONTOLOGICAL APPROACH TO CULTURAL HERITAGE DOCUMENTATION

Deriving from the complex nature of cultural heritage conservation it is the need for enhancing a systematic but flexible organization of expert knowledge in the field. Such organization should address comprehensively the interrelations and complementariness among the different factors that come into play in the understanding of diagnostic and intervention problems. The purpose of MONDIS is to endorse this kind of organization. The approach consists in applying an ontological representation to the field of heritage conservation in order to establish an appropriate processing of data. The system allows replicating in a computer readable form the basic dependence among factors influencing the description, diagnosis and intervention of damages to immovable objects. More specifically MONDIS allows to input and search entries concerning object description, structural evolution, location characteristics and risk, component, material properties, surveys and measurements, damage typology, damage triggering events and possible interventions. The system supports searching features typical of standard databases, as it allows for the digitalization of a wide range of information including professional reports, books, articles and scientific papers. It also allows for computer aided retrieval of information tailored to user's requirements. The foreseen outputs will include a web user interface and a mobile application for visual inspection purposes

The return of an experimentally N-saturated boreal forest to an N-limited state : observations on the soil microbial community structure, biotic N retention capacity and gross N mineralisation

To find out how N-saturated forests can return to an N-limited state, we examined the recovery of biotic N sinks under decreasing N supply. We studied a 40-year-old experiment in Pinus sylvestris forest, with control plots, N0, three N treatments, N1-N3, of which N3 was stopped after 20 years, allowing observation of recovery. In N3, the N concentration in foliage was still slightly elevated, but the N uptake capacity of ectomycorrhizal (ECM) roots in N3 was no longer lower than in N0. Per area the amount of a biomarker for fungi, here mainly attributed ECM, was higher in N3 and N0 than in N1 and N2. Retention of labeled (NH4)-N-15 (+) by the soil was greater in the control (99 %) and N3 (86 %), than in N1 (45 %) and N2 (29 %); we ascribe these differences to biotic retention because cation exchange capacity did not vary. Gross N mineralisation and retention of N correlated, negatively and positively, respectively, with abundance of ECM fungal biomarker. The results suggest a key role for ECM fungi in regulating the N cycle. We propose, in accordance with plant C allocation theory, that recovery is driven by increased tree below-ground C allocation to ECM roots and fungi

Delivery of Alginate Scaffold Releasing Two Trophic Factors for Spinal Cord Injury Repair

International audienceSpinal cord injury (SCI) has been implicated in neural cell loss and consequently functional motor and sensory impairment. In this study, we propose an alginate-based neurobridge enriched with/without trophic growth factors (GFs) that can be utilized as a therapeutic approach for spinal cord repair. The bioavailability of key GFs, such as Epidermal Growth factor (EGF) and basic Fibroblast Growth Factor (bFGF) released from injected alginate biomaterial to the central lesion site significantly enhanced the sparing of spinal cord tissue and increased the number of surviving neurons (choline acetyltransferase positive motoneurons) and sensory fibres. In addition, we document enhanced outgrowth of corticospinal tract axons and presence of blood vessels at the central lesion. Tissue proteomics was performed at 3, 7 and 10 days after SCI in rats indicated the presence of anti-inflammatory factors in segments above the central lesion site, whereas in segments below, neurite outgrowth factors, inflammatory cytokines and chondroitin sulfate proteoglycan of the lectican protein family were overexpressed. Collectively, based on our data, we confirm that functional recovery was significantly improved in SCI groups receiving alginate scaffold with affinity-bound growth factors (ALG+GFs), compared to SCI animals without biomaterial treatment

Dissociative electron attachment to 2,4,6-TCA and 2,4,6-TBA molecules

2,4,6-trichloroanisole and 2,4,6-tribromoanisole were investigated by means of Electron Transmission Spectroscopy and two different types of Dissociative Electron Attachment spectrometers, see Fig. 1. The dominant dissociative decay channels of the temporary molecular negative ions lead to formation of Clˉ and Brˉ in the low electron energy region. Formation of long-lived parent anions is observed at thermal electron energies. Their relative intensity depends on the experimental time window, ~36 s in the case of the static magnet mass analyzer and ~200 s for the quadrupole mass analyzer employed