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Background Pediatric carpal injuries are a clinical challenge due to their non-specific clinical features and occult nature on plain radiography. We hypothesized that early magnetic resonance imaging (MRI) will allow prompt diagnosis and treatment stratification, and that distal pole fracture of the scaphoid requires a shorter duration of immobilization. This study aims to assess the injury pattern and clinical outcomes of under-16-year-olds treated with acute post-traumatic wrist injuries in accordance with the unit's protocol. Methods All patients under the age of 16 years treated for suspected pediatric wrist injuries in our tertiary pediatric hand and upper limb service were included. Prospectively collected data included patient demographics, radiological findings, treatment and adherence to the unit's protocol. Results There were 151 patients with a mean age of 12 years. The majority (72%) had occult bony injury with radiological evidence of fracture on MRI. The sensitivity and specificity of plain film radiography were 42.7% and 71.4%, respectively. Almost one in four patients benefitted from early MRI demonstrating no injuries, permitting early mobilization and discharge. The scaphoid was the most commonly injured carpal bone. Non-displaced fractures of the distal pole of the scaphoid in patients over 10 years old were treated with 4 weeks' immobilization with no adverse outcome. Conclusion Standardized care in our unit has yielded good results with low complication rate and fewer hospital appointments. Our results support the routine early use of MRI and a shorter duration of immobilization in fracture of the distal pole of the scaphoid at 4 weeks. Level of Evidence This is a level IV, case series study.

Background and Purposes The wrist is the fourth most common joint to be involved in juvenile inflammatory arthritis (JIA), which is a common rheumatological condition affecting children. Wrist arthroscopy is well established in rheumatoid arthritis, but remains unexplored in JIA. The aim of this study is to investigate the role of wrist arthroscopy in JIA, with focus on those who are refractory to medical management. Methods This is a prospective observational study, including consecutive patients with JIA undergoing arthroscopy between January 2016 and December 2020. Those over the age of 18 years and those with other rheumatological diagnoses were excluded. Data including pre-, intra-, and postoperative variables, demographics, and patient-reported outcomes were collated and are reported using standard measures. Results A total of 15 patients underwent arthroscopy (n = 20 wrists). Synovitis was noted in all wrists on arthroscopy and synovectomy was performed in all cases. Other procedures were performed as indicated during the procedure. The median follow-up duration was 11.3 (interquartile range [IQR] 8.1–24.2) months. Median reduction of 4 (IQR 2.25–6) points on the Visual Analogue Score for pain on loading was noted postoperatively. Grip strength was improved in n = 11/20 wrists and functional improvement was noted in n = 18/20 wrists. Restriction of range of motion was achieved with a shrinkage procedure in patients with hypermobile joints. There were no postoperative complications, and no patients were lost to follow-up. Conclusion In experienced hands, wrist arthroscopy is feasible, safe, and efficacious in the management of JIA, among patients who are refractory to medical management. Level of Evidence This is a Level II study.

Objective Treatment of palmar midcarpal instability (PMCI) remains controversial and children can develop PMCI from asymptomatic hypermobility. Recently, case series have been published regarding the use of arthroscopic thermal shrinkage of the capsule in adults. Reports of the use of the technique in children and adolescents are rare, and there are no published case series. Methods In a tertiary hand center for children's hand and wrist conditions, 51 patients were treated with arthroscopy for PMCI between 2014 and 2021. Eighteen out of 51 patients carried additional diagnosis of juvenile idiopathic arthritis (JIA) or a congenital arthritis. Data were collected including range of movement, visual analog scale (VAS) at rest and with load, and grip strength. Data were used to determine the safety and efficacy of this treatment in pediatric and adolescent patients. Results Mean follow-up was 11.9 months. The procedure was well tolerated and no complications were recorded. Range of movement was preserved postoperatively. In all groups VAS scores at rest and with load improved. Those who underwent arthroscopic capsular shrinkage (ACS) had significantly greater improvement in VAS with load, compared with those who underwent arthroscopic synovectomy alone (p = 0.04). Comparing those treated with underlying JIA versus those without, there was no difference in postoperative range of movement, but there was significantly greater improvement for the non-JIA group in terms of both VAS at rest (p = 0.02) and VAS with load (p = 0.02). Those with JIA and hypermobility stabilized postoperatively, and those with JIA with signs of early carpal collapse and no hypermobility achieved improved range of movement, in terms of flexion (p = 0.02), extension (p = 0.03), and radial deviation (p = 0.01). Conclusion ACS is a well-tolerated, safe, and effective procedure for PMCI in children and adolescents. It improves pain and instability at rest and with load, and offers benefit over open synovectomy alone. This is the first case series describing the usefulness of the procedure in children and adolescents, and demonstrates effective use of the technique in experienced hands in a specialist center. Level of Evidence This is a Level IV study.

Metacarpal joint hyperextension is common cause of postoperative dissatisfaction after trapeziectomy in the management of basal thumb osteoarthritis. The senior author uses this technique to address this biomechanical problem at the time of trapeziectomy.

During the Engineering Validation and Engineering Design Activities (EVEDA) phase (2007-2014) of the International Fusion Materials Irradiation Facility (IFMIF), an advanced engineering design of the High Flux Test Module (HFTM) has been developed with the objective to facilitate the controlled irradiation of steel samples in the high flux area directly behind the IFMIF neutron source. The development process addressed included manufacturing techniques, CAD, neutronic, thermal-hydraulic and mechanical analyses complemented by a series of validation activities. Validation included manufacturing of 1:1 parts and mockups, test of prototypes in the FLEX and HELOKA-LP helium loops of KIT for verification of the thermal and mechanical properties, and irradiation of specimen filled capsule prototypes in the BR2 test reactor. The prototyping activities were backed by several R&D studies addressing focused issues like handling of liquid NaK (as filling medium) and insertion of Small Specimen Test Technique (SSTT) specimens into the irradiation capsules. This paper provides an up-todate design description of the HFTM irradiation device, and reports on the achieved performance criteria related to the requirements. Results of the validation activities are accounted for and the most important issues for further development are identified.

The nanostructure of the ODS Eurofer steel (9% CrWVTa + 0.5% Y2O3) has been studied after irradiation by iron ions to a damaging dose of 32 dpa. This steel in the initial state is characterized by the presence of a significant amount (∼1024 m−3) of nanosized (2–4 nm) clusters containing atoms of V, Y, O, and N. An analysis of the distribution of various chemical elements in the tested volumes has revealed variations in the composition of the matrix and of the nanosized clusters during irradiation. The data obtained were compared with the results for the ODS Eurofer steel subjected to reactor irradiation to a dose of 32 dpa.

Проведено исследование наноструктуры стали ODS Eurofer (9%-CrWVTa + 0.5%Y2O3) после облучения ионами железа до повреждающей дозы 32 сна (смещений на атом). Эта сталь в исходном состоянии характеризуется наличием значительного числа ( 1024 м-3) наноразмерных (2–4 нм) кластеров, содержащих атомы V, Y, O и N. Анализ распределения различных химических элементов в исследованных объемах выявил изменение состава матрицы и наноразмерных кластеров под облучением. Проведено сравнение полученных данных с результатами реакторного облучения стали ODS Eurofer до дозы 32 сна.

International audience; A key experiment in the accelerator-driven systems (ADS) roadmap, the MEGAwatt PIlot Experiment (MEGAPIE) (1 MW) was initiated in 1999 in order to design and build a liquid lead–bismuth spallation target, then to operate it at the Swiss spallation neutron facility, SINQ, at the Paul Scherrer Institute (PSI). The target has been designed, manufactured at ATEA (France), then set-up, fitted with all the ancillary systems, on an integral test stand at PSI for off-beam tests dedicated to thermo-hydraulic and operability tests, carried out during the last months of 2005. The system was then placed with its ancillary system in the SINQ facility, for final operation under irradiation, which was carried out from August 14th to December 21st, 2006. The irradiation allowed very important results to be obtained, including those showing the very good operational behavior of the target. Moreover, a lot of results in the thermal hydraulic and neutronics fields, and gas analysis contributed to validating the design studies and the assumed theoretical models. Decommissioning of the target has been carried out and PSI teams have prepared samples (760) for post-irradiation examination (PIE). The samples have been distributed to the following partner laboratories: Commissariat à l’énergie atomique et aux énergies alternatives (CEA), Karlsruhe Institute of Technology (KIT), Paul Scherrer Institute (PSI), SCK·CEN, and the US Los Alamos National Laboratory (LANL). The Centre national de la recherche scientifique (CNRS) and ENEA will also contribute to the PIE to be carried out in the SCK-Mol and PSI hot laboratories, respectively. The goal is to study the changes to the structural material properties caused by the harsh environment of high temperatures, contact with flowing liquid metal (lead–bismuth eutectic, LBE), and proton irradiation. After presenting an overview of the project history, we describe the target decommissioning, PIE sample preparation and distribution, and highlight the first results that have been obtained. The successful behavior of the target and the coming results about irradiated materials will provide to ADS community with unique operational feedback, paving the way to develop high-power spallation targets as neutron sources and for future ADS-based options for the transmutation of nuclear wastes.

The global land temperature trend may be biased due to remaining inhomogeneities. Well-homogenized national datasets on average clearly show more warming than global collections when averaged over the region of common coverage. For this study we have collected a dataset with more than 40 national and regional average monthly temperature series (called "national" from now on). National datasets can be better homogenized than global ones. More data is available at national weather services to serve as a reference in the detection and correction of breaks. More stations and knowledge of the local climatology can help in selecting better references that are expected to have the same climate signal. More metadata is available nationally on network-wide breaks and to determine the right date of the statistically detected breaks. Furthermore, better homogenization methods are available for regional networks. Here we compare these national datasets to the global collections BEST, CRUCY, CRUTEM4, GHCNv3 and GISS. For all datasets the country average series have been computed. A subset of 10 well-homogenized national datasets shows a clearly stronger temperature trend, which is several tenths of a degree Celsius per century larger and mostly statistically significant. These differences are seen for the entire period between 1800 and now. The differences are smallest for CRUTEM4 and CRUCY, which include homogenized data from many of our national datasets. The differences are largest for BEST and GISS. GHCN represents a middle case. We are working on better understanding these differences by comparing all datasets, which range from raw data to data homogenized by various methods and which use a range of different methods to compute the national average. We look for relationships between the methods used for homogenization and averaging and the trend differences. In an accompanying poster, we i) review the literature on trend uncertainties due to remaining inhomogeneities, ii) present work on the ability of homogenization methods to detect inhomogeneities and correct trend biases, especially in case of a low signal-to-noise ratio, iii) review recent work on various causes of cooling biases in the climate record due to inhomogeneities and iv) present the work of the Parallel Observations Science Team of the International Surface Temperature Initiative (ISTI-POST) to study the influence of these factors using parallel measurements.

Formation of different types of nanosized Al-containing oxide precipitates in an Fe-Cr-Al alloy (PM 2000) was studied by electron energy loss spectroscopy (EELS) using a transmission electron microscope (TEM). It was shown that Y3Al5O12 (garnet) and YAlO3 (perovskite) as well as -Al2O3 and -Al2O3 precipitates can be distinguished by analysing the O-K energy loss near-edge structure (ELNES). The formation of interface-specific phases on Al2O3/YAlO3, Al2O3/matrix and Y3Al5O12/matrix interfaces was also investigated by specially resolved EELS analysis. Applicability and sensitivity of the EELS method in the study of steel precipitates were discussed. A sharp pre-peak or “pre-shoulder” in the O-K edge was observed and studied by means of spatially resolved EELS of oxide inclusions. The intense pre-peak was found to be caused by radiation damage induced by the electron beam of the Al hydroxide phase inside Al2O3 inclusions. This phase formed due to the incorporation of hydrogen in the matrix during mechanical alloying in the hydrogen atmosphere. The “pre-shoulder” of the main O-K feature measured on the inclusion/matrix interface results from the formation of a thin Ti-O layer.

The gas evolution permeation technique has been used to investigate the interaction of hydrogen with the oxide dispersion strengthened (ODS) reduced activation ferritic–martensitic (RAFM) steel EUROFER. The measurements were performed over the temperature range of 420–777 K with hydrogen driving pressures ranging from 2.5 × 103 to 1.0 × 105 Pa. The resultant diffusive transport parameters are a permeability of Φ (mol m−1 Pa−1/2 s−1) = 1.22 × 10−8 exp(−34.6 (kJ mol−1)/RT), a diffusivity of D (m2 s−1) = 1.33 × 10−6 exp(−30.4 (kJ mol−1)/RT) and a Sieverts’ constant of Ks (mol m−3 Pa−1/2) = 9.21 × 10−3 exp(−4.2 (kJ mol−1)/RT). The resultant trapping parameters have been a trap density of Nt = 2.0 × 1025 m−3 and trapping energy of Et = 44.9 kJ mol−1. All the hydrogen transport parameters obtained for the ODS-EUROFER are compared to the available data obtained for the base material EUROFER in order to study the influence of the particular micro-structure of ODS in the hydrogen transport. Other RAFM steels of the same kind are included in the comparative analysis. The presence of yttria nanoparticles induces a marked trapping phenomenon and provokes a decrease in the diffusivity and an increase in the solubility of hydrogen in the material at low temperature.

Transmission electron microscopy (TEM) as well as corresponding analytical techniques, such as high resolution TEM (HRTEM), energy dispersive X-ray (EDX) analysis, electron energy loss spectroscopy...

Oxide-dispersion-strengthened (ODS) ferritic-martensitic steels with yttrium oxide (Y(2)O(3)) have been produced by mechanical alloying and hot isostatic pressing for use as advanced material in fusion power reactors. Argon gas, usually widely used as inert gas during mechanical alloying, was surprisingly detected in the nanodispersion-strengthened materials. Energy-filtered transmission electron microscopy (EFTEM) and electron energy loss spectroscopy (EELS) led to the following results: (i) chemical composition of ODS particles, (ii) voids with typical diameters of 1-6 nm are formed in the matrix, (iii) these voids are filled with Ar gas, and (iv) the high-density nanosized ODS particles serve as trapping centers for the Ar bubbles. The Ar L(3,2) energy loss edge at 245 eV as well as the absorption features of the ODS particle elements were identified in the EELS spectrum. The energy resolution in the EEL spectrum of about 1.0 eV allows to identify the electronic structure of the ODS particles.

An oxide dispersion strengthened ferritic-martensitic steel with yttrium oxide (Y2O3) was produced by mechanical alloying and hot isostatic pressing techniques for high-performance structures of fusion energy devices. The structure of the nanometer-sized Y2O3 particles analysed by HRTEM shows a strong correlation of its crystallographic orientation with the alloy lattice. The orientation correlations [1 1 0]YO∥[1 1 1]FeCr and were found. The strong orientation correlation appears during HIPing processes around 1050°C, which is significantly lower than the melting temperature of Y2O3 that amounts to 2500°C.

Oxide dispersion strengthened (ODS) materials for structural applications in future fusion power reactors would allow to increase the operating temperature to approximately 650 °C. Two ODS variants of the 9%CrWVTa-RAFM steel EUROFER 97 with Y2O3 contents of 0.3 and 0.5 wt% have been produced. The microstructure of both powder and compacted material has been characterised by means of optical and electron microscopy (SEM, TEM). Tensile tests performed between RT and 850 °C show an increase of yield strength and ultimate tensile strength by 50% and more compared to the basic steel. The ductility values are sufficiently high. Creep tests between 600 and 700 °C up to test times of 5000 h confirm the superior creep strength of ODS-EUROFER. Impact tests reveal a similar impact behaviour to comparable ODS alloys, but the ductile-to-brittle transition temperature is substantially higher than that of EUROFER 97. Preliminary results of low-cycle fatigue show a promising fatigue behaviour of ODS-EUROFER.

Reduced activation ferritic/martensitic (RAFM) steels are being considered for structural application in potential fusion energy systems. Based on the substantial experience with RAFM developmental steels of OPTIFER type, an industrial 3.5 tons batch of a 9CrWVTa-RAFM steel, called EUROFER 97 had been specified and ordered. A characterisation programme has now been launched to determine the relevant mechanical and physical-metallurgical properties in order to qualify it for fusion application. The hardening, tempering and transformation behaviour of EUROFER is in good agreement with that of other RAFM-steels like OPTIFER and the Japanese industrial scale heat F82H mod. Tensile tests, performed between RT and 750 °C, show comparable strength and ductility values that are not strongly affected by ageing at 580 and 600 °C up to 3300 h. Impact bending tests indicate a superior ductile to brittle transition temperature (DBTT) of EUROFER in the as-received condition compared to that of F82H mod. First results of creep tests between 450 and 650 °C up to test times of 4000 h reveal a creep strength similar to OPTIFER and F82H mod. The first results of the investigations show that it is possible to transfer the good mechanical and structural properties of precursor laboratory melts to an industrial scale melt.

Strain controlled fatigue experiments on the modified ferritic—martensitic 12% Cr-steel Manet have been performed during, after and without irradiation. Continuous push—pull cycling of the hollow fatigue specimens with a cycle ratio R = −1, an axial strain rate of 8 · 10−4 s−1 and total strain ranges Δet between 0.42% and 1.0% has been applied in vacuum (5 · 10−3 Pa) at T = 250°C. For the irradiation, a 104 MeV α-particle beam was used. Compared to unirradiated specimens, in-beam specimens undergo irradiation hardening at an advanced fatigue/implantation stage. Post-irradiation specimens show significantly higher total stress amplitudes and reduced fatigue lives. TEM investigations of in-beam and post-irradiation specimens several helium bubbles with different diameters on internal surfaces and in the matrix.

Aluminum nitride has been proposed as electrically insulating coating in connection with blankets made of vanadium alloys. Irradiations were performed with an applied DC electric field of 100 kV/m, using a 104 MeV α-particle beam. The dose achieved were 0.1 dpa at 300°C, 0.05 dpa at 400°C, and 0.06 dpa at 500°C. The out-of-beam conductivity σ 0 decreased at all temperatures employed during early stage of irradiation. Before 0.02 dpa had been reached, σ 0 dropped to low values of typically (2–4) × 10 −11 (Ω m) −1 . Although a moderate increase can be observed during further irradiation, σ 0 remained below the initial value of the unirradiated specimen for all temperatures. That is, there is no significant evidence for radiation induced electrical degradation. The in-beam conductivity σ, measured continuously during irradiation, also decreased by at least one order of magnitude. Relevant damage dose and ionization rate dependencies of σ and σ 0 will be discussed.

Strain-controlled fatigue experiments under simultaneous irradiation have been performed to investigate the specific loadings of structural materials in next-step fusion devices. All irradiations were done on specimens made of the tempered ferritic/martensitic Cr steel MANET-I at 420°C using a 104 MeV α-particle beam. Continuous push-pull cycling (R = −1) has been applied with total strain ranges Δϵt between 0.5 and 1.0%. Under in-beam conditions at e.g. Δϵt = 0.5% a number of cycles to failure of Nt = 42000, a He concentration of 400 appm and a damage dose of 1.6 dpa has been reached. This Nf is by about a factor of two below the average Nf-value of unirradiated reference tests, but seven times higher than Nf of comparable postirradiated specimens. It was found, that at least at 420°C conventional postirradiation tests are a conservative approach to in-situ conditions, and that in strain-controlled tests Nf is mainly governed by the time evolution of the irradiation-induced hardening. Relevant microstructural features like the He-bubble morphology are correlated with the fatigue properties.

Summary Ar-filled bubbles in an oxide-dispersion-strengthened (ODS) alloy were characterized by analytical transmission electron microscopy. Energy dispersive X-ray analysis combined with nanoscale imaging was employed for quantitative analysis of Ar gas locked in a bubble 6 nm in size. As the Ar bubbles are formed at the ODS particles – matrix interface, the known Ti2Y2O7 composition and size of ODS particles served as a reference in quantification of the Ar signal and for the calculation of the bubble size and the Ar density inside. The Ar pressure was also calculated by modified Van der Waals equation.

Tensile specimens of a 75Pd-25Ag alloy have been homogeneously implanted with helium at 300°C to simulate the effect of helium produced by the β-decay of tritium during steady state operation of diffusors used in plasma exhaust clean up of a fusion reactor. The influence of helium dose (0–3000 appm) and environment (vacuum, hydrogen gas) on the mechanical and microstructural properties were studied at 300°C, the typical operation temperature of a diffusor. Specimens containing 3000 appm helium showed a moderate increase in tensile strength of 27% and a significant reduction in total elongation of 83% when examined under vacuum. Under a hydrogen atmosphere both the strength and ductility were approximately one third lower. With increasing helium content a change from a ductile transcrystalline fracture to a predominantly brittle intercrystalline one occurs. A TEM analysis of the He bubble distribution is presented and correlated with the tensile properties.

Push-pull fatigue specimens of the tempered fully martensitic steel DIN 1.4914 (heat MANET) were irradiated at the High Energy Dual Beam Facility of KfK. The influence of helium dose (≤ 200 appm) and He dose/damage ratio (10–170) have been studied in strain controlled fatigue experiments with hold times at an irradiation and test temperature of 450°C. Compared with continuously cycled specimens, hold times of 2 min reduce the number of cycles to failure Nf by 18–20% in the compressive and by 35–40% in the tensile phase. Under all irradiation conditions the reduction in Nf was found to be less than 30%. Both tensile and compressive strain holds lead to a stress relaxation of 70–80 MPa. In all tests with hold times, fatigue life was found to be dominated by fatigue damage and not by creeep damage. The observed microstructural changes are correlated with the fatigue properties.

Fatigue specimens of the normalized and tempered fully martensitic steel DIN 1.4914 were irradiated at the Dual Beam Facility of KfK. The influence of irradiation temperature (300–600 °C), damage level (0.3–1.2 dpa), helium dose ( ≦ 200 appm) and He dose damage ratio have been studied in strain controlled low cycle fatigue experiments at temperatures equal to the irradiation temperature. All irradiated specimens showed cyclic softening with a slope of the stress amplitude very similar to that of unirradiated ones. In specimens with 200 appm He and 1.2 dpa the stress amplitude at 300 °C is increased by 11% and it is slightly decreased above 450°C. Under all irradiation conditions only small changes in the number of cycles to failure were observed and the fracture mode is found to remain always ductile and transgranular.

Reduced activation ferritic-martensitic alloys (RAFM) are primary candidates for structural application in breeding blankets of fusion reactor plants, mainly due to their excellent swelling resistance and low activation properties. By the selection a of specific production route for ODS-Eurofer steel of the second generation, which included rolling and appropriate thermal treatments, DBTT could be shifted from values between +60 and +100°C for hipped ODS-Eurofer to values between −40 and −80°C° [1]. In addition ductility was improved significantly. This ductility improvement of the steel properties could be attributed to dislocation pinning on ODS particles. TEM examination of the ODS particle/matrix interface is a step toward understanding of the pinning mechanism and herewith the possibility to predict the steel properties.

Extended abstract of a paper presented at MC 2007, 33rd DGE Conference in Saarbrücken, Germany, September 2 – September 7, 2007

Oxide dispersion strengthened (ODS) reduced activation ferritic/martensitic steels are being developed for structural applications in future fusion reactors since they would allow consistently increasing the operation temperature The 9%CrWVTa Eurofer-97 steel has been selected as a base material strengthened by Y2O3 contents of 0.3 and 0.5 wt% and produced in a powdermetallurgical route by mechanical alloying and hot isostatic pressing (HIP). The mechanical properties are strongly correlated with Y2O3 particle average size and spatial distribution, therefore small-angle neutron scattering (SANS) is quite useful to investigate how these evolve in the course of the production steps. Solid polycrystalline samples as well as mechanically alloyed powders have been investigated after thermal treatments thus simulating the HIP conditions. The obtained SANS results show that annealing at high temperature results in a redistribution of scattering centres sizes, which might be attributed to the growth of small Yttria particles and possibly of larger carbides.