Improved calibration procedures for the EM27/SUN spectrometers of the COllaborative Carbon Column Observing Network (COCCON)

In this study, an extension on the previously reported status of the COllaborative Carbon Column Observing Network’s (COCCON) calibration procedures incorporating refined methods is presented. COCCON is a global network of portable Bruker EM27/SUN FTIR spectrometers for deriving column-averaged atmospheric abundances of greenhouse gases. The original laboratory open-path lamp measurements for deriving the instrumental line shape (ILS) of the spectrometer from water vapour lines have been refined and extended to the secondary detector channel incorporated in the EM27/SUN spectrometer for detection of carbon monoxide (CO). The refinements encompass improved spectroscopic line lists for the relevant water lines and a revision of the laboratory pressure measurements used for the analysis of the spectra. The new results are found to be in good agreement with those reported by Frey et al. (2019), and discussed in detail. In addition, a new calibration cell for ILS measurements was designed, constructed and put into service. Spectrometers calibrated since January 2020 were tested using both methods for ILS characterisation, open path (OP) and cell measurements. We demonstrate that both methods can detect the small variations of ILS characteristics between different spectrometers, but the results of the cell method indicate a systematic bias of the OP method. Finally, a revision and extension of the COCCON network instrument-to-instrument calibration factors for XCO2, XCO, and XCH4 is presented, incorporating 47 new spectrometers (of 83 in total by now). This calibration is based on the reference EM27/SUN spectrometer operated by the Karlsruhe Institute of Technology (KIT) and spectra collected by the collocated TCCON station Karlsruhe. Variations in the instrumental characteristics of the reference EM27/SUN during 2014 to 2017 were detected probably arising from realignment and the dual-channel upgrade performed in early 2018. These variations are considered in the evaluation of the instrument-specific calibration factors in order to keep all tabulated calibration results consistent.

Identification of Modal Parameters for Reinforcement of Walls in Earthen Ruins

The protection of earthen sites plays an important role in the context of preservation of cultural heritage, especially in the inheritance and promotion of history and culture. The aim of the paper is to present the essential results of an ongoing research on a reinforced rammed earthen wall in Suoyang City (Guazhou, China). The wall vibrations caused by ambient actions were analyzed using the stochastic subspace algorithm to estimate the modal parameters of the wall. The frequencies of the first three orders are 3.566 Hz, 5.003 Hz, and 6.250 Hz, and the corresponding modes are first-order transverse bending, second-order left and right torsion, and third-order vertical bending, respectively. Then, according to the data of elastic modulus obtained in the lab, the finite element calculation is carried out, and referring to the results of field measurement, the revised elastic modulus value is 205.90 MPa. It is worth mentioning that the revised value is significantly improved from the original laboratory value, and it is also indicated that the seismic performance of the reinforced wall has been significantly improved. The present work is expected to provide a theoretical basis for reinforcement, protection, and seismic control of earthen ruins.

Investigation of the effect of vacuum on the curing of mixtures on a silicate binder

The article presents the results of a study of the effect of vacuuming on the curing processes of liquid‑glass mixtures. The method of conducting experiments using an original laboratory vacuum installation and the mechanisms of curing a liquid‑glass mixture with various hardening methods are described. Studies have shown that vacuuming can signifi antly accelerate the curing and increase the strength of the mixture while reducing the content of the silicate binder. This; in turn; facilitates the knockability of liquid‑glass mixtures and expands the prospects for using these environmental friendly mixtures in foundry as an alternative to sands based on organic binders.

DEVELOPMENT OF A TEST BENCH FOR SIMULATION OF ELEMENTS OF GRANULAR MATERIAL PROCESSING SYSTEMS

The paper deals with the development of an original laboratory test bench for modeling elements of granular material processing systems. The core of the test bench is a modified abrasive blasting machine. In this version of the test bench, a changeable module in the form of a flat curved channel imitates an elbow of a pneumatic conveying system. The test bench will allow studying the erosive wear of such elbows.

Substitution Arg140Gly in HA/H7 attenuated highly pathogenic avian influenza virus FPV/Rostock/34 (H7N1)

The H7 subtype of avian influenza viruses (AIV) stands out among other AIV. H7 viruses circulate in ducks, poultry, equine and have repeatedly caused outbreaks of disease in humans. In order to study the pathogenicity factors of H7N1 viruses, several laboratory variants of the A/FPV/Rostock/34 (H7N1) strain were obtained by passages in the chicken lungs. After 10 such passages, a variant was obtained that differed from the parent virus by amino acid substitutions Val109Phe in PB2, Gln621Lys in PB1, Thr32Ala and Leu586Phe in PA Gly140Arg in HA1 and Ala101Thr in HA2 (numbering by H3), Ser82Arg in M2, Arg118Lys and Met124Arg in NS1. No differences were found in proteins NA, NP, M1 and NS2. The resulting variant was hundreds of times more pathogenic for chickens than the original laboratory variant of the virus. The study of intermediate passages showed that the jump in pathogenicity occurs sharply between the fifth and sixth passage through the chicken lungs. By cloning these variants, a pair of strains (R5p and R6p) were obtained, and the complete genomes of these strains were sequenced. Single amino acid substitution was revealed, namely Gly140Arg in HA1. It is important to emphasize that this substitution is a reversion, since Arg is located in position 140 HA1 of original the A/FPV/Rostock/34 (H7N1) virus (GenBank). This amino acid is located at the head part of the hemagglutinin, adjacent to the receptor-binding site. In addition to the increased pathogenicity, R6p differs from R5p by an increased affinity for a negatively charged receptor analogue, an increased affinity for MDCK cells, while maintaining a receptor specificity profile.

Rate-and-State friction as a bulk visco-plastic flow law that includes generation, diffusion, and healing of distributed damage

<p>The rate- and state-dependent friction (RSF) laws (Dieterich, 1979, JGR; Ruina, 1983, JGR-SE) have been widely successful in capturing the behavior of sliding surfaces in laboratory settings, as well as reproducing a range of natural fault slip phenomena in numerical models.</p><p>Studies of exhumed fault zones make it clear that faults are not two-dimensional features at the junction of two distinct bodies of rock, but instead evolve into complex damage zones that show clear signs of multi-scale fracturing, grain diminution, hydro-thermal effects and chemical and petrological changes. Many of these observed factors have been experimentally verified, and several studies have furthered our theoretical understanding of earthquakes and other seismic phenomena as volumetric, bulk-rock processes, including Sleep (1995, 1997), Lyakhovsky and Ben-Zion et al. (2011, J. Mech. Phys. Solids; 2014, PAGeoph; 2014,  J. Mech. Phys. Solids; 2016, GJI), Niemeijer, Chen, van den Ende et al. (2007, 2016, JGR-SE; 2018, Tectonophysics), Roubicek (2014, GJI), and Barbot (2019, Tectonophysics).</p><p>While the established numerical modeling approach of simulating faults as planar features undergoing friction can be a useful and powerful homogenization of small-scale volumetric processes, there are also cases where this practice falls short -- most notably when studying faults that grow and evolve in response to a changing tectonic environment. This is mainly due to the computational challenges associated with automating the construction of a fault-resolving conformal mesh.</p><p>Motivated by this issue, we formulate a generalization of RSF as a plastic or viscous flow law with generation, diffusion, and healing of damage that gives rise to mathematically and numerically well-behaved finite shear bands that closely mimic the behavior of the original laboratory-derived formulation. The proposed formulation includes the well-known RSF laws for an infinitely thin fault as a limit case as the damage diffusion length scale tends to zero. In contrast to previous theoretical work we focus only on a mathematical formalism that is used to generalize and regularize the existing RSF laws in order to retain close correspondence to existing experimental and numerical results. We will demonstrate the behavior of this new bulk RSF formulation with results of 1D and 2D numerical simulations, and hope to engage in a preliminary discussion of the physical implications.</p>

On the Issue of Storing Seed Grain in a Vacuum Container

The article presents a fundamentally new technology for storing seed material in conditions typical for small and medium-sized farms. (Research purpose) The research purpose is in studying a container with a controlled air and gas environment in it. (Materials and methods) The article presents studies in order to obtain initial data for calculating the volume of the carbon dioxide storage tank using an original laboratory installation consisting of a sealed container with a vacuum gauge mounted on the lid. The process of seed respiration is characterized by the respiratory coefficient Kd, which is determined by the ratio of the volume of carbon dioxide released to the volume of oxygen absorbed in the air. (Results and discussion) During the aerobic respiration of seeds in the container, the composition of the air in the intergranular space is constantly changing, while the content of carbon dioxide increases and oxygen decreases. When determining the mass of the air medium, it is possible to obtain an expression that obeys the Mendeleev - Klayperon equation for an ideal gas for external climatic conditions, on the basis of which it is possible to calculate the mass content of carbon dioxide in the air mixture. (Conclusions) The article recommends the technology of storing seed grain in a sealed container with a controlled air environment and a system of forced aeration of the grain mass. It is necessary to create and maintain a vacuum of the air mixture in the working volume of the sealed container within 0.66 MPa. The forced aeration of the grain embankment should be started when the oxygen content in the air mixture located in the carbon dioxide storage tank exceeds 7 percent.

An Homage to Otto Stern

This chapter outlines an International Symposium held at Frankfurt on 1–5 September 2019. It marked the centennial of quantitative experiments with molecular beams, pioneered by Otto Stern. The European Physical Society declared Stern’s original laboratory a Historic Site, the fifth in Germany. As a graduate student in 1955, I learned about Otto Stern (1888–1969) and the impact of his molecular beams on quantum physics. I was intrigued and undertook crossed-beam experiments at Berkeley. In 1960 Otto came to a seminar that I gave. Later I met him, and heard some of his stories. The rest of the chapter describes his Nobel Prize and other Fests. In 1958 his long-term colleague, Immanuel Estermann, organized a celebration and Festschrift for Otto’s 70th birthday. In 1988, as a guest editor, I organized a Festschift for the centennial of Otto’s birth. That year, the German Physical Society established the Stern-Gerlach Prize as its highest award for experimental physics. Bretislav Friedrich and I wrote three papers about Stern. Since 2000, Horst Schmidt-Böcking at Frankfurt and colleagues have produced historical articles, along with a book about Otto, edited and bound all of his research papers into books, and diligently pursued letters to and from Otto, collecting them into large volumes.

KONCEPCJA BADAŃ EKSPERYMENTALNYCH ZACHOWANIA SIĘ MATERIAŁU OBSYPKI PIASKOWEJ UKRYĆ OCHRONNYCH DLA LUDNOŚCI CYWILNEJ

The article proposes the concept of experimental dynamic tests of aggregate behavior - sand used as a material for covering temporary protective shelters for the population and civil defense. These shelters are part of the construction shielding infrastructure useful in crisis situations. Laboratory tests of loose soil, including sand, with impact loads, are based on the Split Hopkinson Pressure Bar using a clamp. The work describes both this experimental method and the original laboratory stand for impact tests based on a pneumatic launcher with a projectile - bar. This position was built at the Institute of Civil Engineering of the Military University of Technology taking into account the requirements of generally applicable legal provisions. Examples of preliminary experimental research on the behavior of selected aggregate - dry sand under dynamic load - are presented.