We propose two methods for evaluating athermal recombination corrected (arc) displacement damage parameters in ion irradiations employing the computer code SRIM (Stopping and Range of Ions in Matter). The first method consists of post-processing the detailed SRIM output for all simulated damage events and re-calculating according to the arc damage model. In the second method, an approximate empirical formula is devised which gives the average displacements in the arc damage model as a function of the corresponding quantity according to the standard Norgett-Robinson-Torrens model, which is readily obtained from SRIM.

This paper aims at clarifying, by means of an integrated experimental and theoretical approach, the properties of the interaction between interstitial nitrogen (N) and irradiation generated lattice defects in α-Fe. For this purpose, N-doped and pure Fe specimens were irradiated at low temperature by high energy protons. The evolution of radiation defects and their interaction with N was monitored by electrical resistivity measurements during post-irradiation annealing. In parallel, density functional theory (DFT) was employed to study the properties of N solutes, vacancies and their mutual interaction in the Fe matrix. The DFT results were confronted to the experiment via kinetic rate theory modelling, employed to quantitatively simulate the measured resistivity evolution. One of the most important results is the experimental validation of the theoretically predicted strong binding energy of vacancy-N complexes, which reconciles previous discrepancies. Furthermore, a quantitative interpretation is provided of how irradiation competes with nitride precipitation.

The influence of recrystallization on the recovery of radiation damage in tungsten (W) was investigated. Polycrystalline cold-rolled W foils were annealed in the temperature range between 110 0 and 160 0 degrees C and recrystallization and grain growth was observed. Subsequently, the specimens were irradiated with 7 MeV protons at cryogenic temperature. The induced radiation damage and its recovery during isochronal annealing treatments was monitored by in-situ measurements of the electrical resistivity. We observe that the recrystallized samples exhibit (a) a significant reduction in total defect recovery and (b) changes in characteristic features of the recovery spectra with respect to the as-received ones. These results are discussed and correlated to the effect of grain boundaries and dislocations on the radiation defect reactions. (c) 2021 Elsevier B.V. All rights reserved.

The Tandem Accelerator Laboratory of NCSR "Demokritos," Athens, Greece, is presented. A technical description of the laboratory, the installed setups together with currently implemented upgrades and associated funded projects are given. A few highlights as well as future upgrade plans and access possibilities to external users are also presented.

Pure and C-doped Fe specimens were irradiated with 5 MeV protons at cryogenic temperature at the NCSR-"Demokritos" TANDEM accelerator in order to investigate the interactions between carbon atoms and radiation defects. During the subsequent post-irradiation isochronal annealing up to 180 K the defects start to migrate and interact either mutually or with the C impurities. The defect evolution is observed by in-situ electrical resistivity recovery measurements. Comparison of results from pure and C-doped Fe specimens reveals the effect of C solute atoms on the defect kinetics.

Resistivity recovery experiments are performed on α-Fe and an Fe - 220 at. ppm C alloy after 5 MeV proton irradiation at cryogenic temperature of 50 K. By comparing the recovery spectra of pure Fe and the Fe-C alloy we are able to resolve the effect of carbon atoms on the point defect kinetics. It is observed that carbon interacts with both interstitial and vacancy type of defects and delays their annihilation. At temperatures above 500 K the formation of carbides reduces the resistivity of the alloy.

Following the IAEA Technical Meeting on `Advanced Methodologies for the Analysis of Materials in Energy Applications Using Ion Beam Accelerators', this paper reviews the current status of ion beam analysis (IBA) techniques and some aspects of ion-induced radiation damage in materials for the field of materials relevant to fusion. Available facilities, apparatus development, future research options and challenges are presented and discussed. The analysis of beryllium and radioactivity-containing samples from future experiments in JET or ITER represents not only an analytical but also a technical challenge. A comprehensive list of the facilities, their current status, and analytical capabilities comes alongside detailed descriptions of the labs. A discussion of future issues of sample handling and the current status of facilities at JET complete the technical section. To prepare the international IBA community for these challenges, the IAEA technical meeting concludes the necessity for determining new nuclear reaction cross-sections and improving the inter-laboratory comparability by defining international standards and testing these via a round-robin test.

As an important part of fusion materials research, evaluation of radiation damage in fusion materials has been emphasized more than a half century. In order to improve our understanding of radiation damage in fusion materials, an upgrade has been performed of the materials irradiation facility IR2, which is located at the NCSR “Demokritos” 5.5 MV TANDEM accelerator. The upgraded facility allows irradiation at higher ion beam currents while ensuring that the target temperature remains below 10 K. It provides in-situ electrical resistivity measurements on several samples for real-time monitoring of radiation damage as well as in-situ post-irradiation annealing up to 300 K. The upgraded IR2 facility has been successfully employed in radiation damage and recovery studies of metallic materials with applications in fusion research.

The experimental results of Takaki et al. [1] on the stage I resistivity recovery of electron irradiated iron are analyzed using the analytical theory of diffusion annealing formulated by Simpson & Sossin [2] and Schroeder [3] taking into account the recent first-principles calculations of Fu et al. [4] regarding the mobility of interstitials. Excellent agreement between theory and experiment is obtained by a minimal set of adjustable parameters. The results show that the diffusion annealing equations can be successfully employed for the analysis of recovery experiments in iron.

Iron magnetic moment enhancement is observed following the irradiation of iron films with 490 keV Fe$^+$ at room temperature. The iron magnetic moment enhancement increases to saturation with irradiation dose. Theenhanced magnetic moment decays exponentially to its value before the irradiation with a time constant of 5.2 months. The iron magnetic moment enhancement is attributed to the creation of vacancy clusters having a concentration of about 20 %, whereas the relaxation effects is attributed to the dissociation of these clusters.

490keV Fe+ ion irradiation of 200nm thick Fe films was found to induce both structural and magnetic changes. Both, the lattice constant and the grain size increase as a function of dose and both properties follow the same power law. Irradiation induces a depth dependent magnetic profile consisting of two sublayers. The top Fe sublayer has a magnetic moment higher than that of the Fe before the irradiation whereas the bottom sublayer lower. The two sublayers are connected with the effects of Fe+ irradiation, i.e. the top sublayer with the depth in which mainly radiation damage occurs whereas the bottom one with the implantation of impinging Fe+ ions. The magnetic moments of the two sublayers have a non-monotonous variation with irradiation dose depicting a maximum for the top sublayer and a minimum for the bottom one at 96.2 dpa (‘displacements per atom’). The magnetic moment enhancement/reduction is discussed in relation with the atomic volume variation in the case of atom displacements and/or implantation effects.

The effect of carbon on the point defect migration properties in Fe–Cr alloys with a concentration of 11 at.% Cr is studied by means of resistivity recovery measurements after low temperature proton irradiation. The presence of carbon mainly affects features of the resistivity recovery spectra in the temperature ranges of (a) 150–200K, which are linked to self-interstitial defects, and (b) 400–500K, which are probably due to vacancy and vacancy-carbon complexes. The experimental results are discussed in terms of the possible interactions of carbon with radiation defects and its influence on solute atom re-ordering.

Waste lignocellulosic biomass is an abandoned agro-industrial by-product including wheat straw. Lignocellulosics can be used as natural adsorbents for dyes, heavy metal salts and hydrocarbons in wastewater, seawater, rivers and lakes. The modification of lignocellulosic waste biomass can provide relatively low-cost adsorbents with increased sorption capacity and biodegradability, appropriate for the removal of dyes, heavy metal salts and oil spills from aquatic media. Titanium dioxide is a low-cost, environmentally friendly, abundant material that is well known for its photocatalytic properties. In this work lignocellulosic adsorbents (wheat) have undergone surface modification by nanostructured titania and the photocatalytic materials produced have been characterized in detail, as per their physicochemical properties with SEM, Raman spectroscopy, FT-IR Spectroscopy, adsorption isotherms and BET specific surface area. The photocatalytic activity of these organic-inorganic hybrids has been studied as per their ability to degrade commonly examined pollutants, such as azo dyes. The proposed innovative modification yields environmentally friendly organic-inorganic hybrid materials of low-cost but high added value, because: (i) the adsorbed pollutants are degraded by light, (ii) landfilling or incineration of the used biomass is avoided, thus preventing adverse effects on groundwater or air quality, respectively, and (iii) the produced material is recyclable and reusable.

Waste lignocellulosic biomass can be considered as a residual agro-industrial by-product with more representative species straw, cob, and husk because of their abundance in most countries. Lignocellulosics can be used as natural adsorbents for dyes, heavy metal salts and hydrocarbons in wastewater, seawater, rivers and lakes. The modification of lignocellulosic waste biomass can provide relatively low-cost adsorbents with increased sorption capacity and biodegradability, appropriate for the removal of dyes, heavy metal salts and oil spills from aquatic media. This work deals with the laboratory scale experimental design and execution of tests on the surface of original and modified wheat straw adsorbent, using Brunauer–Emmett–Teller (BET) specific surface area analyzer, Micro-Raman spectroscopy, Fourier transform infrared (FT-IR) and X-ray diffraction analysis (XRD). For the evaluation of microporocity of the highly heterogeneous adsorption materials, appropriate non-destructive spectroscopic techniques were used, as BET using nitrogen and Scanning Electron Microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS). Key-Words: waterbodies pollution, adsorption, experimental design, wheat straw, oil spill, BET, FT-IR, XRD, Raman. 1 Introductory Analysis Waste lignocellulosic biomass is natural adsorbent for dyes, heavy metal salts and hydrocarbons from wastewater, seawater, rivers and lakes [1]. Moreover, the thermochemical treatment of lignocellulosic waste biomass can provide low-cost adsorbents with increased sorption capacity and high biodegradability and for removing dyes [2, 3], heavy metals [4] and oil spills [5, 6] from different aquatic environments. Straws are renewable raw materials for production of cellulose, glucose, bioethanol and other chemicals. Straws are often used for dyes, heavy metals and hydrocarbon spills removal. In this case, the surface properties of straws play a crucial role. Since leaves and stems are the main components of straw, the surface of these plant parts should be considered in order to understand the relevant adsorption parameters, as they appear in the corresponding simulation models. More specifically, this capacity depends primarily on the chemical composition structure of straw tissue that has direct contact with oil. The adsorption capacity depends heavily on the structure of the straw stalks in the bundles, the distances between them, the diameter and cross-sections of each stalk and leaf [7]. A large number of lignocellulosic materials, like walnut shell [1], biomass [8], raw bagasse [9], carbonized pith bagasse [10], acetylated sugarcane bagasse [11] , peat [12, 13], fatty acid grafted sawdust [14], carbonized fir fibers [15], barley straw [9, 10, 16-20], wheat straw [21, 22], rice straw [23], rice husk [24-25], sludge, garlic and onion peels Recent Advances in Energy, Environment and Financial Planning ISBN: 978-960-474-400-8 74 [26], and banana trunk fiber [27], can be used as adsorbents. In this work the surface of wheat straw, a lignocellulosic biomass adsorbent, before and after chemical modification by autohydrolysis [28], was studied under laboratory conditions, by carrying out BET, Raman spectroscopy, XRD, FT-IR, and SEM with EDS. 2 Materials and Methods The wheat straw used in this work was obtained from the Kapareli village, close to the Thiva city at the Kopaida area in central Greece (harvesting year 2012), as a suitable source for full-scale industrial applications. The moisture content of the material when received was 8.8% w/w; after screening, the fraction with particle sizes between 10 and 20 mm was isolated. The autohydrolysis process was performed in a 3.75-L PARR 4843 batch reactor. The isothermal hydrolysis time was 10 min (not including the nonisothermal preheating and cooling periods). The reaction was catalyzed by the organic acids that were produced by wheat straw during autohydrolysis at a liquid-to-solid ratio of 20:1. The volume of the liquid phase (water) was 2000 mL and the solid material dose (wheat straw) was 100 g (i.e., 91.25 g on dry basis). The stirring speed was 50 rpm. The reaction ending temperature of 200°C was reached after 60 min of preheating [5, 28]. The surface areas and porosity of the powders were determined by the Brunauer-Emmet-Teller (BET) method [29]. Liquid nitrogen isotherms at 77 K were obtained, using the Autosorb-1 MP (Quantachrome) porosimeter. Before each measurement, the samples were degassed, under high vacuum 10 mbar for 24 h, at 353K in the outgassing stations of the instrument. The selected program of relative pressures covered all the pore sizes from the ultra-micropore to the large mesopores region (1x10<=P/Po<1).The tolerance and equilibration time of all the pressure points were set to 0 and 10 respectively. Before performing the measurements, all samples were turned into powders using a hummer mill. The Raman spectra [30] of the samples were recorded on a Renishaw inVia Reflex spectrometer in backscattering configuration employing a near infrared (NIR) diode laser (λ =785 nm) as excitation source. Rayleigh scattering was rejected with a 100 cm cut-off dielectric edge filter, and analysis of the scattered beam was performed on a 250 mm focal length spectrometer along with a 1200 lines/mm diffraction grating and a high-sensitivity chargecoupled device (CCD detector). The intensity of laser was set at 0.5 mW/μm. Subtraction of the luminescence background (%) was performed for the wavenumbers range between 120 and 1700 cm. Raman spectra analysis has been performed by a polynomial fitting interpolation routine, while spectral deconvolution has been carried out by nonlinear least-squares fitting of the Raman peaks to a mixture of Lorentzian and Gaussian line shapes, providing the peak position, width, height, and integrated intensity of each Raman band. IR spectra [31] were collected on a Thermo Scientific Nicolet 6700 FTIR with N2 purging system. Spectra were acquired using a single reflection ATR (attenuated total reflection) SmartOrbit accessory equipped with a singlebounce diamond crystal (spectral range: 10,000–55 cm, angle of incidence: 45◦). A total of 32 scans were averaged for each sample and the resolution was 4 cm. The spectra were obtained against a single-beam spectrum of the clean ATR crystal and converted into absorbance units. Data were collected in the range 4000–400 cm. The powder XRD patterns of the origin and the pretreated samples were measured by a SIEMENS D5005 X-Ray Diffractometer using Ni-filtered CuKa (λ=0.154 nm) radiation at 45 kV and 40 mA and continuous scan mode. The XRD patterns were recorded in the scan range 2θ=5-70 , at scan rate step=0.04 , dwell time=3 sec, i.e. total scan time approximately 1 h and 30 min. The study of untreated and pretreated wheat straw samples by scanning electron microscopy (SEM) was conducted using an FEI INSPECT SEM equipped with an EDAX super ultra thin window analyzer for energy dispersive X-ray spectroscopy (EDS). The SEM analysis was performed in low vacuum operation mode (P=0.53 Torr) in order to avoid charging effects. The magnification was X750, X2,500, X7,500 and X20,000. 3 Results and Discussion The adsorption capacity of straw depends upon porosity, as well as chemical reactivity of functional groups at the adsorbent surface. The BET isotherms are given in Fig. 1 for (a) untreated and (b) modified wheat straw samples. The pore size distribution resulted from these BET isotherms is presented in Fig. 2. The BET values range were 3.0 to 3.1 m/g (see Table 1). Following the analysis of the results obtained by N2 adsorption porosimetry on untreated and autohydrolyzed wheat straw, we were able to compare the properties (BET surface area, total pore Recent Advances in Energy, Environment and Financial Planning ISBN: 978-960-474-400-8 75 volume and mean pore diameter) for each of the samples. It is clear that pretreatment causes the increase in the mean pore diameter from 17.5 to 29.7 nm and total pore volume from 0.013 to 0.023 mL/g. The higher value of total pore volume is observed on the modified material. This imposes the most profound changes on the material, something that was also confirmed by Raman spectra (Fig. 3) and FT-IR spectroscopy (Figs. 5-8). On the contrary, besides the fact that the hydrothermal treatment has an effect on the mean pore diameter (Table 1), the pore size distribution does not present a significant change (see Fig. 2). In Fig. 4, the XRD pattern of original/raw and treated/autohydrolyzed wheat straw shows a higher crystallinity as regards the cellulose of pretreated sample. FT-IR spectroscopy was applied to identify the functional groups responsible for Methylene Blue (MB) sorption (See Fig. 5). The spectra indicate the band at around 1050 cm, which is attributed to CO stretching of the methoxy group (-OCH3) of the aromatic ring of lignin or to the C-O bonds of cellulose / hemicelluloses constituents (see Table 2). Other hydroxyl groups and carboxyl groups (i.e., phenolic, aliphatic extractives), also negatively charged, could be involved in the sorption of MB via electrostatic interaction. Carboxyl and hydroxyl groups were identified as the most important groups responsible for the sorption of MB [32, 33]. The higher MB sorption observed could be attributed to the higher lignin content and the difference in water extractives which contain tannins, i.e., OH groups [34]. Peaks at about 1600 cm, 1400 cm, 1350 cm 1 and 890 cm are characteristic bands of the MB spectrum. For both samples, untreated and pretreated wheat straw, the observed trend was the same: (i) Reduction of dominant peaks (3400 from the OH stretching of phenol group and 2900 cm from the CH stretching of methyl group) associated with the Cr(VI) load (see Fig. 6 and Table 2); these phenomena show that a metal binding process is taking place at the surface of the adsorbents. (ii) Elimination of peaks indicating that surface –OH group is one o

Waste lignocellulosic biomass is an abandoned agro-industrial by-product including wheat straw, barley straw, spruce sawdust, pine sawdust, corn stover, sugarcane bagasse, etc. Lignocellulosics can be used as natural adsorbents for dyes, heavy metals and hydrocarbons in wastewater, seawater, rivers and lakes. The thermochemical modification of lignocellulosic waste biomass can provide relatively low-cost adsorbents with increased sorption capacity and biodegradability, appropriate for the removal of chemicals, heavy metals and oil spills from aquatic media. This work deals with the design and performance of measurements on the surface of original and modified wheat straw and spruce sawdust adsorbents, using Brunauer Emmett Teller (BET) specific surface area analyser, Fourier transform infrared (FT-IR) and Micro-Raman spectroscopy. For the evaluation of microporocity of the materials, non-destructive spectroscopic techniques were used, as Liquid Nitrogen Porosimetry and Scanning Electron Microscopy (SEM), which were proved appropriate for the study of highly heterogeneous solid samples.

This work deals with the surface characterization of unmodified/modified wheat straw biomass, before and after adsorption under laboratory conditions. The changes induced by autohydrolysis modification process at biomass surface are studied with scanning electron microscopy (SEM) with a view to drawing qualitative and quantitative conclusions about the induced changes and understanding the modification mechanism triggered at micro-scale and correlating them with the treatment process parameters in order to allow the manipulation of the adsorption properties of the produced material by properly adjusting the modification process parameters. Besides topography, the chemical composition at micro-scale using SEM with energy dispersive X-ray analysis (SEM/EDS) has also been investigated. The study has been performed on SEM INSPECT of FEI that allows low vacuum conditions, a prerequisite for handling biomass specimens that not only contain high levels of moisture and gasses but have insulating properties, as well. Moreover, as the biomass material is not homogeneous, it was necessary to study several microscopic fields and many specimens to assure statistically significant findings, according to small sample theory.