DEM simulations of the frictional and frictionless polydisperse packings of spheres under uniaxial compression

The uniaxial compression of polydisperse assemblies of spherical frictional and frictionless particles is modeled with the discrete element method (DEM). The normal particle size distribution with standard deviation of particle mean diameter in the range from 0% to 80% was applied. The series of numerical tests have been conducted to study the micromechanical and macromechanical properties of packings of spheres. The micro-scale analyses included distribution of contact forces and average coordination number, whereas macromechanical study included the elasticity, stress transmission and angle of internal friction in the assemblies. The linear increase in solid fraction was observed for standard deviation of particle mean diameter increasing up to 50% in assemblies of both, frictional and frictionless spheres under pressure of 100kPa. Further increase in particle size heterogeneity decreased solid fraction in systems. The increase in coefficient of interparticle friction resulted in decrease in solid fraction by above 10% in the whole range of variability of SD value due to the different space-filling properties of frictional particles. The stiffness of samples increased with compressive loads increasing, however no clear effect of particle size polydispersity on the effective elastic modulus of mixtures was found in frictional sphere packings. The effective elastic modulus increased with SD value increasing up to 50% in sample composed of smooth particles that decreased for higher SD values. Discrete element method predicted decrease in pressure ratio with standard deviation of particle mean diameter increasing up to 50%. Further increase in particle size polydispersity increased value of the parameter. Increase in coefficient of interparticle friction to 0.4 resulted in about 40% decrease in pressure ratio in sphere packings

Development of a selftriggered high counting rate ASIC for readout of 2D gas microstrip neutron detectors

In the frame of the DETNI project a 32-channel ASIC suitable for readout of a novel 2D thermal neutron detector based on a hybrid low-pressure Micro-Strip Gas Chamber with solid 157Gd converter has been developed. Each channel delivers position information, a fast time stamp of 2 ns resolution and the signal amplitude (called energy below). The time stamp is used for correlating the signals from X and Y strips while the amplitude is used for finding the center of gravity of a cluster of strips. The timing and energy information are stored in derandomizing buffers and read out via token ring architecture

n-XYTER: A CMOS read-out ASIC for a new generation of high rate multichannel counting mode neutron detectors

For a new generation of 2-D neutron detectors developed in the framework of the EU NMI3 project DETNI [1], the 128-channel frontend chip n-XYTER has been designed. To facilitate the reconstruction of single neutron incidence points, the chip has to provide a spatial coordinate (represented by the channel number), as well as time stamp and amplitude information to match the data of x- and y-coordinates. While the random nature of the input signals calls for self-triggered operation of the chip, on-chip derandomisation and sparsi cation is required to exploit the enormous rate capability of these detectors ( 4 106cm2s1). The chosen architecture implements a preampli er driving two shapers with di erent time constants per channel. The faster shaper drives a single-pulse discriminator with subsequent time-walk compensation. The output of this circuit is used to latch a 14-bit time stamp with a 2 ns resolution and to enable a peak detector circuit fed by the slower shaper branch. The analogue output of the peak detector as well as the time stamp are stored in a 4-stage FIFO for derandomisation. The readout of these FIFOs is accomplished by a token-ring based multiplexer working at 32 MHz, which accounts for further derandomisation, sparsi cation and dynamic bandwidth distribution. The chip was submitted for manufacturing in AMS's C35B4M3 0.35µm CMOS technology in June 2006

Comparisons between SCIAMACHY and ground-based FTIR data for total columns of CO, CH₄, CO₂ and N₂O

Total column amounts of CO, CH4, CO2 and N2O retrieved from SCIAMACHY nadir observations in ist near-infrared channels have been compared to data from a ground-based quasi-global network of Fourier-transform infrared (FTIR) spectrometers. The SCIAMACHY data considered here have been produced by three different retrieval algorithms, WFM-DOAS (version 0.5 for CO and CH4 and version 0.4 for CO2 and N2O), IMAP-DOAS (version 1.1 and 0.9 (for CO)) and IMLM (version 6.3) and cover the January to December 2003 time period. Comparisons have been made for individual data, as well as for monthly averages. To maximize the number of reliable coincidences that satisfy the temporal and spatial collocation criteria, the SCIAMACHY data have been compared with a temporal 3rd order polynomial interpolation of the ground-based data. Particular attention has been given to the question whether SCIAMACHY observes correctly the seasonal and latitudinal variability of the target species. The present results indicate that the individual SCIAMACHY data obtained with the actual versions of the algorithms have been significantly improved, but that the quality requirements, for estimating emissions on regional scales, are not yet met. Nevertheless, possible directions for further algorithm upgrades have been identified which should result in more reliable data products in a near future

Overview of IFMIF-DONES diagnostics: Requirements and techniques

The IFMIF-DONES Facility is a unique first-class scientific infrastructure whose construction is foreseen in Granada, Spain, in the coming years. Strong integration efforts are being made at the current project phase aiming at harmonizing the ongoing design of the different and complex Systems of the facility. The consolidation of the Diagnostics and Instrumentation, transversal across many of them, is a key element of this purpose. A top-down strategy is proposed for a systematic Diagnostics Review and Requirement definition, putting emphasis in the one-of-a-kind instruments necessary by the operational particularities of some of the Systems, as well as to the harsh environment that they shall survive. In addition, other transversal aspects such as the ones related to Safety and Machine Protection and their respective requirements shall be also considered. The goal is therefore to advance further and solidly in the respective designs, identify problems in advance, and steer the Diagnostics development and validation campaigns that will be required. The present work provides an overview of this integration strategy as well as a description of some of the most challenging Diagnostics and Instruments within the facility, including several proposed techniques currently under study

Nomenclature of allergic diseases and hypersensitivity reactions: Adapted to modern needs: An EAACI position paper

The exponential growth of precision diagnostic tools, including omic technologies, molecular diagnostics, sophisticated genetic and epigenetic editing, imaging and nano-technologies and patient access to extensive health care, has resulted in vast amounts of unbiased data enabling in-depth disease characterization. New disease endotypes have been identified for various allergic diseases and triggered the gradual transition from a disease description focused on symptoms to identifying biomarkers and intricate pathogenetic and metabolic pathways. Consequently, the current disease taxonomy has to be revised for better categorization. This European Academy of Allergy and Clinical Immunology Position Paper responds to this challenge and provides a modern nomenclature for allergic diseases, which respects the earlier classifications back to the early 20th century. Hypersensitivity reactions originally described by Gell and Coombs have been extended into nine different types comprising antibody- (I-III), cell-mediated (IVa-c), tissue-driven mechanisms (V-VI) and direct response to chemicals (VII). Types I-III are linked to classical and newly described clinical conditions. Type IVa-c are specified and detailed according to the current understanding of T1, T2 and T3 responses. Types V-VI involve epithelial barrier defects and metabolic-induced immune dysregulation, while direct cellular and inflammatory responses to chemicals are covered in type VII. It is notable that several combinations of mixed types may appear in the clinical setting. The clinical relevance of the current approach for allergy practice will be conferred in another article that will follow this year, aiming at showing the relevance in clinical practice where various endotypes can overlap and evolve over the lifetime

(Photo)physical properties of new molecular glasses end-capped with thiophene rings composed of diimide and imine units

New symmetrical arylene bisimide derivatives formed by using electron-donating-electron-accepting systems were synthesized. They consist of a phthalic diimide or naphthalenediimide core and imine linkages and are end-capped with thiophene, bithiophene, and (ethylenedioxy)thiophene units. Moreover, polymers were obtained from a new diamine, N,N′-bis(5- aminonaphthalenyl)naphthalene-1,4,5,8-dicarboximide and 2,5- thiophenedicarboxaldehyde or 2,2′-bithiophene-5,5′-dicarboxaldehyde. The prepared azomethine diimides exhibited glass-forming properties. The obtained compounds emitted blue light with the emission maximum at 470 nm. The value of the absorption coefficient was determined as a function of the photon energy using spectroscopic ellipsometry. All compounds are electrochemically active and undergo reversible electrochemical reduction and irreversible oxidation processes as was found in cyclic voltammetry and differential pulse voltammetry (DPV) studies. They exhibited a low electrochemically (DPV) calculated energy band gap (Eg) from 1.14 to 1.70 eV. The highest occupied molecular orbital and lowest unoccupied molecular orbital levels and Eg were additionally calculated theoretically by density functional theory at the B3LYP/6-31G(d,p) level. The photovoltaic properties of two model compounds as the active layer in organic solar cells in the configuration indium tin oxide/poly(3,4-(ethylenedioxy)thiophene):poly(styrenesulfonate)/active layer/Al under an illumination of 1.3 mW/cm2 were studied. The device comprising poly(3-hexylthiophene) with the compound end-capped with bithiophene rings showed the highest value of Voc (above 1 V). The conversion efficiency of the fabricated solar cell was in the range of 0.69-0.90%

COVID-19 vaccination in patients receiving allergen immunotherapy (AIT) or biologicals:EAACI recommendations

Immune modulation is a key therapeutic approach for allergic diseases, asthma and autoimmunity. It can be achieved in an antigen-specific manner via allergen immunotherapy (AIT) or in an endotype-driven approach using biologicals that target the major pathways of the type 2 (T2) immune response: immunoglobulin (Ig)E, interleukin (IL)-5 and IL-4/IL-13 or non-type 2 response: anti-cytokine antibodies and B-cell depletion via anti-CD20. Coronavirus disease 2019 (COVID-19) vaccination provides an excellent opportunity to tackle the global pandemics and is currently being applied in an accelerated rhythm worldwide. The vaccine exerts its effects through immune modulation, induces and amplifies the response against the severe acute respiratory syndrome coronavirus (SARS-CoV-2). Thus, as there may be a discernible interference between these treatment modalities, recommendations on how they should be applied in sequence are expected. The European Academy of Allergy and Clinical Immunology (EAACI) assembled an expert panel under its Research and Outreach Committee (ROC). This expert panel evaluated the evidence and have formulated recommendations on the administration of COVID-19 vaccine in patients with allergic diseases and asthma receiving AIT or biologicals. The panel also formulated recommendations for COVID-19 vaccine in association with biologicals targeting the type 1 or type 3 immune response. In formulating recommendations, the panel evaluated the mechanisms of COVID-19 infection, of COVID-19 vaccine, of AIT and of biologicals and considered the data published for other anti-infectious vaccines administered concurrently with AIT or biologicals

DEM simulations of the frictional and frictionless polydisperse packings of spheres under uniaxial compression

The uniaxial compression of polydisperse assemblies of spherical frictional and frictionless particles is modeled with the discrete element method (DEM). The normal particle size distribution with standard deviation of particle mean diameter in the range from 0% to 80% was applied. The series of numerical tests have been conducted to study the micromechanical and macromechanical properties of packings of spheres. The micro-scale analyses included distribution of contact forces and average coordination number, whereas macromechanical study included the elasticity, stress transmission and angle of internal friction in the assemblies. The linear increase in solid fraction was observed for standard deviation of particle mean diameter increasing up to 50% in assemblies of both, frictional and frictionless spheres under pressure of 100kPa. Further increase in particle size heterogeneity decreased solid fraction in systems. The increase in coefficient of interparticle friction resulted in decrease in solid fraction by above 10% in the whole range of variability of SD value due to the different space-filling properties of frictional particles. The stiffness of samples increased with compressive loads increasing, however no clear effect of particle size polydispersity on the effective elastic modulus of mixtures was found in frictional sphere packings. The effective elastic modulus increased with SD value increasing up to 50% in sample composed of smooth particles that decreased for higher SD values. Discrete element method predicted decrease in pressure ratio with standard deviation of particle mean diameter increasing up to 50%. Further increase in particle size polydispersity increased value of the parameter. Increase in coefficient of interparticle friction to 0.4 resulted in about 40% decrease in pressure ratio in sphere packings