<p>It is necessary to carry out the in-situ detection based on the meteorological rocket to deepen the cognitive level of the middle atmosphere environment. However, the effective utilization of rocket data has been limited by a lack of systematic research into data accuracy and the physical mechanisms influencing measurements. In this study, temperature and wind profiles between 20 and 60 km were obtained over northwest China using two meteorological rockets equipped with thermistors and BeiDou positioning, supplemented by a temperature correction technique. The detection results are compared with satellite, empirical model and reanalysis data. An error analysis was performed by integrating the characteristics of the drop sounding process and atmospheric disturbances. The results indicate that the rocket-derived data are of satisfactory quality, with altitude-dependent trends in temperature and wind profiles consistent with those from other sources. Observed discrepancies come from the deviation of the matching data in time and space and the excessive measurement error in the initial fall stage. Also, it is found that the instability of the parachute causes poor positioning data quality and fast falling speed, leading to significantly larger measurement errors at corresponding altitudes. Additionally, the profile from the first detection exhibited more pronounced fluctuations, attributable to the breaking of high-altitude gravity waves. The dissipation of these waves reduces atmospheric stability and generates denser small-scale layered structures on the profile, making significant wind field changes at lower altitudes through the momentum deposition.</p>
<p>The Earth's energy imbalance is the difference between incoming solar radiation and outgoing reflected and emitted radiation from the Earth, and quantifies the current ongoing accumulation of energy in the Earth's climate system. There are indications that the imbalance is growing, and it is important to be able to measure and monitor this quantity to better constrain future changes. The reflected shortwave component of the outgoing radiation depends on surface and atmospheric properties, which leads to strong directional variations associated with the angular geometry relative to the incoming sunlight and the observer. The effect of this anisotropy on global average measurements from wide-field-of-view radiometers has been the topic of some investigation in the past, and results from an earlier study suggest that this effect could potentially lead to substantial systematic biases in the context of the global mean reflected shortwave radiation. Here we simulate wide-field-of-view instruments on satellites in polar, sun-synchronous and precessing orbits, as well as constellations of these types of satellite orbits, with both Lambertian and anisotropic shortwave reflection. Reference top-of-atmosphere radiative fluxes are taken from the Clouds and the Earth's Radiant Energy System synoptic data product and combined with angular dependence models that were developed for the Earth Radiation Budget Experiment. We find that the polar regions appear brighter and the midlatitudes appear dimmer with anisotropic reflection, but both the estimated global annual mean and the estimated interannual trend only exhibit limited sensitivity to whether Lambertian or anisotropic reflection is assumed. With anisotropic reflection, the estimated global annual mean root-mean-square sampling error is at most 0.11 <span class="inline-formula">W m<sup>−2</sup></span> provided that at least two complementary satellites are used, compared with at most 0.09 <span class="inline-formula">W m<sup>−2</sup></span> in the case of Lambertian reflection. The magnitude of the difference in the estimated interannual trend is at most 0.07 <span class="inline-formula">W m<sup>−2</sup></span> per decade, and typically only <span class="inline-formula">∼</span> 0.01 <span class="inline-formula">W m<sup>−2</sup></span> per decade. Analysis of the angular sampling of these satellites reveals that the anisotropic reflection requires sufficient sampling of viewing zenith angle and relative azimuth angle, in addition to the solar zenith angle. However, we conclude that it is possible to choose satellite orbits so that the sampling error is not substantially affected by reflected shortwave anisotropy.</p>
P. Thiruvengadam, P. Thiruvengadam, G. Lesage
et al.
<p>In recent years, the application of compact and cost-effective deployable X-band polarimetric radars has gained in popularity, particularly in regions with complex terrain. The deployable radars generally use a radome constructed by joining multiple panels using metallic threads to facilitate easy transportation. As a part of the ESPOIRS project, Laboratoire de l'Atmosphère et des Cyclones has acquired an X-band meteorological radar with a four-panel radome configuration. In this study, we investigated the effect of the radome on the measured polarimetric variables, particularly differential reflectivity and differential phase. Our observations reveal that the metallic threads connecting the radome panels introduce power loss at vertical polarization, leading to a positive bias in the differential reflectivity values. To address the spatial variability bias observed in differential reflectivity and differential phase, we have developed a novel algorithm based on the discrete Fourier transform. The algorithm's performance was tested during an intense heavy-rainfall event caused by Cyclone Batsirai on Réunion Island. The comparative and joint histogram analysis demonstrates the algorithm's effectiveness in correcting the spatial bias in the polarimetric variables.</p>
<p>In this work, the T-matrix approach is exploited to produce simulations of spectral polarimetric variables (spectral differential reflectivity, <span class="inline-formula"><i>s</i><i>Z</i><sub>DR</sub></span>, spectral differential scattering phase, <span class="inline-formula"><i>s</i><i>δ</i><sub>HV</sub></span>, and spectral correlation coefficient, <span class="inline-formula"><i>s</i><i>ρ</i><sub>HV</sub></span>) for observations of rain acquired from slant-looking W-band cloud radar. The spectral polarimetric variables are simulated with two different methodologies, taking into account instrument noise and the stochastic movement of the raindrops, introduced by raindrop oscillations and by turbulence. The simulated results are then compared with rain Doppler spectra observations from W-band radar for moderate rain rate conditions. Two cases, differing in levels of turbulence, are considered. While the comparison of the simulations with the measurements presents a reasonable agreement for equi-volume diameters less than 2.25 mm, large discrepancies are found in the amplitude (but not the position) of the maxima and minima of <span class="inline-formula"><i>s</i><i>Z</i><sub>DR</sub></span> and, more mildly, of <span class="inline-formula"><i>s</i><i>δ</i><sub>HV</sub></span>. This pinpoints a general weakness in approximating raindrop as spheroids to simulate radar backscattering properties at the W-band.</p>
<p>This study investigates the impact of microstructure geometry on the thermal and turbulence responses of electrically heated fiber-optic (FO) cables under varying flow conditions and turbulence intensities for the purposes of sensing flow direction. The underlying measurement principle is the directionally sensitive heat loss from electrically heated FO cables with imprinted microstructures exposed to turbulent airflows resembling a long hot-wire anemometer. Using the COMSOL Multiphysics 6.0 finite-element software, this study explores a wider range of different configurations of filled-coned and hollow-coned microstructures of varying size compared to existing studies. The research identifies optimal combinations which maximize temperature differences (<span class="inline-formula">Δ<i>T</i></span>) across FO cables with cones pointing in opposite directions while balancing key design criteria such as sensitivity to wind speed and minimizing the FO-cables' PVC coverage. We demonstrate that FO cables with hollow-coned microstructures (radius <span class="inline-formula">=</span> 24 mm, height <span class="inline-formula">=</span> 24 mm, and spacing <span class="inline-formula">=</span> 15 mm) outperform their filled-coned counterparts, maintaining <span class="inline-formula">Δ<i>T</i></span> values above 2 K across a broader range of wind speeds and turbulence intensities. Notably, the hollow-cone configuration sustains a temperature difference of up to 0.8 K at a 60° wind attack angle. The findings implicate substantial improvements for an optimized FO cable design in atmospheric boundary layer studies, enabling more accurate measurements of wind direction, distributed turbulent heat fluxes, and vertical wind speed perturbations using fiber-optic distributed sensing (FODS). Future work shall validate the findings under field conditions to assess the robustness and real-world applicability of the optimized design.</p>
<p>Wind and temperature observations from aircraft are of major importance for aviation meteorology and numerical weather prediction (NWP). The European Meteorological Aircraft Derived Data Centre (EMADDC) system processes aircraft surveillance data received from air traffic control (ATC) and other partners and converts them into upper-air observations of wind and temperature. Only so-called Mode-S Enhanced Surveillance (Mode-S EHS) data can be used because these data contain the air vector and ground vector of the aircraft from which a wind vector can be inferred. Temperature is derived from true airspeed and Mach number measurements. To produce high-quality observations, the data are processed in three steps: pre-processing, processing, and post-processing. The pre-processing is needed to obtain high-quality information and to calculate several correction values for correcting temperature observations and heading values. Processing converts the aircraft data into meteorological information, and finally post-processing guarantees that only high-quality information is made available.</p>
<p>The EMADDC system processes around <span class="inline-formula">75×10<sup>6</sup></span> surveillance observations per day and produces over <span class="inline-formula">55×10<sup>6</sup></span> observations of quality-controlled wind observations and <span class="inline-formula">32×10<sup>6</sup></span> temperature observations in the European airspace per day. The average age of the observation is around 5 to 10 min, depending on the method of data delivery (files via ftp or streaming constantly).</p>
<p>The quality of the observations produced is verified by comparing these observation to other upper-air wind and temperature observations from radiosondes and Aircraft Meteorological Data Relay (AMDAR) and comparing them with NWP data. The quality of wind observations is almost identical to AMDAR, and the quality of the temperature of EMADDC observations is lower but with a bias of around zero, while AMDAR exhibits a positive bias of 0.5 K.</p>
<p>This paper presents the EMADDC (R2.2) system, operational since 2019.</p>
Summary. The main calculation methods for designing foundations and foundations in Central Africa are considered. The methodology for calculating foundations and foundations in Central Africa is analyzed and compared. Geotechnical calculations are an integral part of the design of foundations and foundations of buildings, especially in Central Africa, where geological, climatic and environmental factors can significantly affect the stability of structures. This work considers the main aspects affecting geotechnical calculations, including a detailed geological survey of the site, which allows determining the types of soils, their physical and mechanical properties and the level of groundwater. An important stage is the assessment of the mechanical properties of soils, such as bearing capacity, water permeability and compressibility, which affect the choice of the type of foundation. The work also analyzes different types of foundations, in particular strip, slab and pile, taking into account the loads that they must withstand, as well as the specifics of soil conditions. The article analyzes the existing methods for this region, in particular the use of drilling and laboratory soil testing. Effective approaches to the selection of foundation types for various geotechnical situations are identified. The article also describes soil investigation methods and principles of foundation design that ensure the stability and safety of buildings in conditions typical of Central Africa. Geotechnical calculations are a crucial component in the design of foundations for buildings, especially in regions with complex geological and climatic conditions, such as Central Africa. This region presents unique challenges for engineers due to the variety of soil types, seasonal rainfall, high temperatures and different groundwater levels. Proper geotechnical analysis ensures the stability, safety and durability of structures. The main factors affecting the design of foundations include soil properties such as strength, compressibility and shear resistance, as well as the state of groundwater, which affects soil stability. Areas with weak or expansive soils often require deep foundations, such as piles or bored piles, while strong soils may allow for shallow foundations. Fluctuations in groundwater levels due to seasonal rains or droughts require special attention to prevent erosion, flooding, or weakening of the foundation base. Geotechnical studies also consider environmental impacts, such as the impact of construction on surrounding ecosystems and local water resources. In addition, compliance with local and international standards ensures that structures meet safety standards. Engineers must also assess climatic factors, such as thermal expansion and contraction, which can affect soil behavior over time. The use of advanced software tools such as PLAXIS and GeoStudio a vital role in modeling soil behavior and predicting potential foundation performance under different conditions. Ultimately, successful geotechnical calculations in Central Africa require a comprehensive approach that takes into account regional soil types, climate and environmental considerations, ensuring the durability and structural integrity of buildings in this challenging environment. Foundation reinforcement is a mandatory stage in the construction of reinforced concrete structures. Its purpose is to strengthen the concrete, allowing it to resist the tensile, bending and shear forces that can act on the foundations. Reinforcement consists of inserting steel bars (rebars) into the concrete to increase its load-bearing capacity. Foundations can be of different types, such as isolated foundations, strip foundations or slab foundations, and the reinforcement varies depending on each type and the constraints of the project. For isolated foundations, for example, the reinforcement usually consists of longitudinal bars arranged in the main direction to resist tension and bending, and transverse bars arranged perpendicularly to counteract transverse forces. This reinforcement must be carefully positioned and positioned to ensure the strength of the foundation. Reinforcing the foundation is also crucial to prevent cracking and warping of the concrete over time. The concrete coating around the reinforcement protects it from corrosion and ensures its durability. Finally, the reinforcement is carried out according to strict standards that take into account the characteristics of the soil, the loads to be supported, and the dimensions of the foundation to ensure safety and stability.
The subject of fractional calculus addresses the research of asserted fractional derivatives and integrations over complex domains and their utilization [...]
F. J. Pérez-Invernón, H. Huntrieser, T. Erbertseder
et al.
<p>Lightning, one of the major sources of nitrogen oxides (NO<span class="inline-formula"><sub><i>x</i></sub></span>) in the atmosphere, contributes to the tropospheric
concentration of ozone and to the oxidizing capacity of the atmosphere. Lightning produces between 2 and 8 Tg N yr<span class="inline-formula"><sup>−1</sup></span> globally and on average about 250 <span class="inline-formula">±</span> 150 mol NO<span class="inline-formula"><sub><i>x</i></sub></span> per flash. In this work, we estimate the moles of NO<span class="inline-formula"><sub><i>x</i></sub></span> produced per flash
(LNO<span class="inline-formula"><sub><i>x</i></sub></span> production efficiency) in the Pyrenees (Spain, France and Andorra) and in the Ebro Valley (Spain) by using nitrogen
dioxide (NO<span class="inline-formula"><sub>2</sub></span>) and cloud properties from the TROPOspheric Monitoring Instrument (TROPOMI) as well as lightning data
from the Earth Networks Global Lightning Network (ENGLN) and from the EUropean Co-operation for LIghtning Detection
(EUCLID). The Pyrenees are one of the areas in Europe with the highest lightning frequencies, which, along with their remoteness as
well as their very low NO<span class="inline-formula"><sub><i>x</i></sub></span> background, enables us to better distinguish the LNO<span class="inline-formula"><sub><i>x</i></sub></span> signal produced by recent lightning in TROPOMI NO<span class="inline-formula"><sub>2</sub></span> measurements. We compare the LNO<span class="inline-formula"><sub><i>x</i></sub></span> production efficiency estimates for eight convective systems in 2018 using two different sets of TROPOMI research products provided by the Royal Netherlands Meteorological Institute (KNMI) and the Deutsches Zentrum für Luft- und Raumfahrt (DLR). According to our results, the mean LNO<span class="inline-formula"><sub><i>x</i></sub></span> production
efficiency in the Pyrenees and in the Ebro Valley, using a 3 h chemical lifetime, ranges between 14 and 103 mol NO<span class="inline-formula"><sub><i>x</i></sub></span>
per flash from the eight systems. The mean LNO<span class="inline-formula"><sub><i>x</i></sub></span> production efficiency estimates obtained using both TROPOMI products and ENGLN lightning data differ by <span class="inline-formula">∼</span> 23 %, while they differ by <span class="inline-formula">∼</span> 35 % when using EUCLID lightning data. The main sources of uncertainty when using ENGLN lightning data are the estimation of background NO<span class="inline-formula"><sub><i>x</i></sub></span> that is not produced by lightning and the time window before the TROPOMI overpass that is used to count the total number of lightning flashes contributing to
freshly produced LNO<span class="inline-formula"><sub><i>x</i></sub></span>. The main source of uncertainty when using EUCLID lightning data is the uncertainty in the detection
efficiency of EUCLID.</p>
<p>The use of low-cost sensors for air quality measurements
has become very popular in the last few decades. Due to the detrimental effects
of particulate matter (PM) on human health, PM sensors like photometers and
optical particle counters (OPCs) are widespread and have been widely
investigated. The negative effects of high relative humidity (RH) and fog
events in the mass concentration readings of these types of sensors are well documented. In the literature, different solutions to these problems – like correction models based on the Köhler theory or machine learning algorithms – have been applied. In this work, an air pre-conditioning method
based on a low-cost thermal dryer for a low-cost OPC is presented. This
study was done in two parts. The first part of the study was conducted in
the laboratory to test the low-cost dryer under two different scenarios. In
one scenario, the drying efficiency of the low-cost dryer was investigated
in the presence of fog. In the second scenario, experiments with hygroscopic
aerosols were done to determine to which extent the low-cost dryer reverts
the growth of hygroscopic particles. In the second part of the study, the
PM<span class="inline-formula"><sub>10</sub></span> and PM<span class="inline-formula"><sub>2.5</sub></span> mass concentrations of an OPC with dryer were compared with the gravimetric measurements and a continuous federal equivalent method (FEM) instrument in the field. The feasibility of using univariate linear regression (ULR) to correct the PM data of an OPC with dryer during field measurement was also evaluated. Finally, comparison measurements between an OPC with dryer, an OPC without dryer, and a FEM instrument during a real fog event are also presented. The laboratory results show that the sensor with the low-cost dryer at its inlet measured an average of 64 % and 59 % less PM<span class="inline-formula"><sub>2.5</sub></span> concentration compared with a sensor without the low-cost dryer
during the experiments with fog and with hygroscopic particles,
respectively. The outcomes of the PM<span class="inline-formula"><sub>2.5</sub></span> concentrations of the low-cost
sensor with dryer in laboratory conditions reveal, however, an excess of
heating compared with the FEM instrument. This excess of heating is also
demonstrated in a more in-depth study on the temperature profile inside the
dryer. The correction of the PM<span class="inline-formula"><sub>10</sub></span> concentrations of the sensor with dryer during field measurements by using ULR showed a reduction of the maximum absolute error (MAE) from 4.3 <span class="inline-formula">µ</span>g m<span class="inline-formula"><sup>−3</sup></span> (raw data) to 2.4 <span class="inline-formula">µ</span>g m<span class="inline-formula"><sup>−3</sup></span> (after correction). The results for PM<span class="inline-formula"><sub>2.5</sub></span> make evident an increase in the MAE after correction: from 1.9 <span class="inline-formula">µ</span>g m<span class="inline-formula"><sup>−3</sup></span> in the raw
data to 3.2 <span class="inline-formula">µ</span>g m<span class="inline-formula"><sup>−3</sup></span>. In light of these results, a low-cost
thermal dryer could be a cost-effective add-on that could revert the effect
of the hygroscopic growth and the fog in the PM readings. However, special
care is needed when designing a low-cost dryer for a PM sensor to produce
FEM similar PM readings, as high temperatures may irreversibly change the
sampled air by evaporating the most volatile particulate species and thus
deliver underestimated PM readings. New versions of a low-cost dryer aiming
at FEM measurements should focus on maintaining the RH at the sensor inlet
at 50 % and avoid reaching temperatures higher than 40 <span class="inline-formula"><sup>∘</sup></span>C in
the drying system. Finally, we believe that low-cost dryers have a very
promising future for the application of sensors in citizen science, sensor
networks for supplemental monitoring, and epidemiological studies.</p>
O. F. C. den Ouden, O. F. C. den Ouden, J. D. Assink
et al.
<p>Geophysical studies and real-time monitoring of natural hazards, such as volcanic eruptions or severe weather events, benefit from the joint analysis of multiple geophysical parameters. However, typical geophysical measurement platforms still provide logging solutions for a single parameter, due to different community standards and the higher cost per added sensor.</p>
<p>In this work, the Infrasound and Environmental Atmospheric data Recorder (INFRA-EAR) is presented, which has been designed as a low-cost mobile multidisciplinary measurement platform for geophysical monitoring. In particular, the platform monitors infrasound but concurrently measures barometric pressure, accelerations, and wind flow and uses the Global Positioning System (GPS) to position the platform. Due to its digital design, the sensor platform can be readily integrated with existing geophysical data infrastructures and be embedded in geophysical data analysis. The small dimensions and low cost per unit allow for unconventional, experimental designs, for example, high-density spatial sampling or deployment on moving measurement platforms. Moreover, such deployments can complement existing high-fidelity geophysical sensor networks. The platform is designed using digital micro-electromechanical system (MEMS) sensors embedded on a printed circuit board (PCB). The MEMS sensors on the PCB are a GPS, a three-component accelerometer, a barometric pressure sensor, an anemometer, and a differential pressure sensor. A programmable microcontroller unit controls the sampling frequency of the sensors and data storage. A waterproof casing is used to protect the mobile platform against the weather. The casing is created with a stereolithography (SLA) Formlabs 3D printer using durable resin.</p>
<p>Thanks to low power consumption (9 Wh over 25 d), the system can be powered by a battery or solar panel. Besides the description of the platform design, we discuss the calibration and performance of the individual sensors.</p>
Along with new construction, the issue of reconstruction of existing buildings and structures in Ukraine remains relevant. The topical issue is to bring a significant number of previously erected buildings in line with today's requirements. Today, many buildings and structures for various reasons are in poor or emergency condition, are preserved or even abandoned. Some of them may get a second life after changing the purpose of the premises, expanding the area, increasing the number of floors, replacing load-bearing structures, etc. However, existing load-bearing structures often require partial or complete reinforcement due to physical wear or increased load after reconstruction. Ensuring reliable operation of buildings after reconstruction, meeting modern needs and requirements while preserving attractive historic facades is an urgent task for many facilities in our country and especially in the capital. The study was performed on the example of a real object in Kyiv on the reconstruction of an administrative building with a superstructure and extension of non-residential premises. The reconstruction project provided for the redevelopment of the main building, which according to archival data was erected by the 1940s. The reconstruction project also provided for an increase in the number of floors in the pavilion, which was added in 2000. And also, the extension of non-residential premises was provided. As part of the study, an analysis of the redistribution of forces in the load-bearing structures was performed, taking into account the subsidence of the foundations of new supports. The change of internal forces in the load-bearing structures of the metal frame was analyzed according to numerical simulations taking into account the influence of the soil base, which is manifested in the occurrence of uneven movements of the bases of the columns. The aim of the study is to analyze the redistribution of forces in the load-bearing structures, taking into account the subsidence of the foundations of new supports based on the results of numerical modeling of the interaction of elements of the system "soil base-foundation-building". To realize this: the bearing capacity of the existing foundations was checked in the conditions of the house reconstruction; the combination of loading on the bases under new support according to results of spatial calculation of a metal framework of an extension is defined; the movement of the bases of the columns was determined to calculate the spatial work of the metal frame of the extension, taking into account the subsidence of the foundations; the analysis of redistribution of efforts in bearing designs is considered taking into account subsidence of the bases of new support. It is established that taking into account the deformation of the foundation base significantly affects the stress state of the aboveground structures of frame structures, which increases the reliability of all elements of the frame.
This paper contains a proposal for a free, nonzero-rest-mass particle’s proper spacetime, determined exclusively by the particle’s rest mass m0\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$m_0$$\end{document} and numbers. The approach defines proper time as de Broglie time, which is isomorphic to a sequence of natural numbers 1,2,…,n\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$1, 2, \ldots , n$$\end{document} that count de Broglie time units (h/c2)(m0-1)\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$(h/c^2)(m_0^{-1})$$\end{document} (see Ferber in Found Phys Lett 9:575, 1996). The approach is based on defining the spatial coordinate as proper following the constructive definition of positive and negative integers as all possible differences of ordered pairs of natural numbers multiplied by the Compton unit (h/c)(m0-1)\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$(h/c)(m_0^{-1})$$\end{document}. The spatial and temporal coordinates that form the particle’s proper spacetime are constructed as Euclidean projections of the de Broglie time. The corresponding expression in the form of an energy-momentum relation reveals the existence, aside from the rest energy term m0c2\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$m_0c^2$$\end{document}, of an additional energy term of the same order of magnitude, which is related to large intervals of the m0\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$m_0$$\end{document}-particle’s proper space. The relation of the numbers-based approach to the foundations of the special theory of relativity and of quantum mechanics is discussed.
<p>The intensity and phase of precipitation at the ground surface can have important implications not only for meteorological and hydrological situations but also in terms of hazards and risks. In the field, Thies disdrometers are sometimes used to monitor the quantity and nature of precipitation with high temporal resolution and very low maintenance and thus provide valuable information for the management of meteorological and hydrological risks. Here, we evaluate the Thies disdrometer with respect to precipitation detection, as well as the estimation of precipitation intensity and phase at a pre-alpine site in Switzerland (1060 m a.s.l.), using a weighing precipitation gauge (OTT pluviometer) and a two-dimensional video disdrometer (2DVD) as a reference. We show that the Thies disdrometer is well suited to detect even light precipitation, reaching a hit rate of around 95 %. However, the instrument tends to systematically underestimate rainfall intensities by 16.5 %, which can be related to a systematic underestimation of the number of raindrops with diameters between 0.5 and 3.5 mm. During snowfall episodes, a similar underestimation is observed in the particle size distribution (PSD), which is, however, not reflected in intensity estimates, probably due to a compensation by snow density assumptions. To improve intensity estimates, we test PSD adjustments (to the 2DVD) and direct adjustments of the resulting intensity estimates (to the OTT pluviometer), the latter of which are able to successfully reduce the systematic deviations during rainfall in the validation period. For snowfall, the combination of the 2DVD and the OTT pluviometer seems promising as it allows for improvement of snow density estimates, which poses a challenge to all optical precipitation measurements. Finally, we show that the Thies disdrometer and the 2DVD agree well insofar as the distinction between rain and snowfall is concerned, such that an important prerequisite for the proposed correction methods is fulfilled. Uncertainties mainly persist during mixed-phase precipitation or low precipitation intensities, where the assignment of precipitation phase is technically challenging, but less relevant for practical applications. We conclude that the Thies disdrometer is suitable not only to estimate precipitation intensity but also to distinguish between rain and snowfall. The Thies disdrometer therefore seems promising for the improvement of precipitation monitoring and the nowcasting of discharge in pre-alpine areas, where considerable uncertainties with respect to these quantities are still posing a challenge to decision-making.</p>
<p>Simultaneous measurements of <span class="inline-formula">CH<sub>3</sub>O<sub>2</sub></span> radical concentrations have
been performed using two different methods in the Leeds HIRAC (Highly
Instrumented Reactor for Atmospheric Chemistry) chamber at 295 K and in
80 mbar of a mixture of <span class="inline-formula">3:1</span> <span class="inline-formula">He∕O<sub>2</sub></span> and 100 or 1000 mbar of synthetic
air. The first detection method consisted of the indirect detection of
<span class="inline-formula">CH<sub>3</sub>O<sub>2</sub></span> using the conversion of <span class="inline-formula">CH<sub>3</sub>O<sub>2</sub></span>
into <span class="inline-formula">CH<sub>3</sub>O</span> by
excess NO with subsequent detection of <span class="inline-formula">CH<sub>3</sub>O</span> by fluorescence assay by
gas expansion (FAGE). The FAGE instrument was calibrated for <span class="inline-formula">CH<sub>3</sub>O<sub>2</sub></span>
in two ways. In the first method, a known concentration of <span class="inline-formula">CH<sub>3</sub>O<sub>2</sub></span>
was generated using the 185 nm photolysis of water vapour in synthetic air
at atmospheric pressure followed by the conversion of the generated OH
radicals to <span class="inline-formula">CH<sub>3</sub>O<sub>2</sub></span> by reaction with <span class="inline-formula">CH<sub>4</sub>∕O<sub>2</sub></span>. This
calibration can be used for experiments performed in HIRAC at 1000 mbar in
air. In the second method, calibration was achieved by generating a near
steady state of <span class="inline-formula">CH<sub>3</sub>O<sub>2</sub></span> and then switching off the photolysis lamps
within HIRAC and monitoring the subsequent decay of <span class="inline-formula">CH<sub>3</sub>O<sub>2</sub></span>, which
was controlled via its self-reaction, and analysing the decay using second-order kinetics. This calibration could be used for experiments performed at
all pressures. In the second detection method, <span class="inline-formula">CH<sub>3</sub>O<sub>2</sub></span> was
measured directly using cavity ring-down spectroscopy (CRDS) using the
absorption at 7487.98 cm<span class="inline-formula"><sup>−1</sup></span> in the <span class="inline-formula"><i>A</i>←<i>X</i></span> (<span class="inline-formula"><i>ν</i><sub>12</sub></span>) band
with the optical path along the <span class="inline-formula">∼1.4</span> m chamber diameter.
Analysis of the second-order kinetic decays of <span class="inline-formula">CH<sub>3</sub>O<sub>2</sub></span> by
self-reaction monitored by CRDS has been used for the determination of the
<span class="inline-formula">CH<sub>3</sub>O<sub>2</sub></span> absorption cross section at 7487.98 cm<span class="inline-formula"><sup>−1</sup></span>, both at 100 mbar of air and at 80 mbar of a <span class="inline-formula">3:1</span> <span class="inline-formula">He∕O<sub>2</sub></span> mixture, from which <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M26" display="inline" overflow="scroll" dspmath="mathml"><mrow><msub><mi mathvariant="italic">σ</mi><mrow class="chem"><msub><mi mathvariant="normal">CH</mi><mn mathvariant="normal">3</mn></msub><msub><mi mathvariant="normal">O</mi><mn mathvariant="normal">2</mn></msub></mrow></msub><mo>=</mo><mo>(</mo><mn mathvariant="normal">1.49</mn><mo>±</mo><mn mathvariant="normal">0.19</mn><mo>)</mo><mo>×</mo><msup><mn mathvariant="normal">10</mn><mrow><mo>-</mo><mn mathvariant="normal">20</mn></mrow></msup></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="146pt" height="18pt" class="svg-formula" dspmath="mathimg" md5hash="a0de3b239060922dec1332333490d350"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="amt-13-2441-2020-ie00001.svg" width="146pt" height="18pt" src="amt-13-2441-2020-ie00001.png"/></svg:svg></span></span> cm<span class="inline-formula"><sup>2</sup></span> molecule<span class="inline-formula"><sup>−1</sup></span> was determined for both pressures. The absorption spectrum
of <span class="inline-formula">CH<sub>3</sub>O<sub>2</sub></span> between 7486 and 7491 cm<span class="inline-formula"><sup>−1</sup></span> did not change shape when
the total pressure was increased to 1000 mbar, from which we determined that
<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M31" display="inline" overflow="scroll" dspmath="mathml"><mrow><msub><mi mathvariant="italic">σ</mi><mrow class="chem"><msub><mi mathvariant="normal">CH</mi><mn mathvariant="normal">3</mn></msub><msub><mi mathvariant="normal">O</mi><mn mathvariant="normal">2</mn></msub></mrow></msub></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="34pt" height="12pt" class="svg-formula" dspmath="mathimg" md5hash="91f987b38bd7263d5c8018a9bd5e863c"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="amt-13-2441-2020-ie00002.svg" width="34pt" height="12pt" src="amt-13-2441-2020-ie00002.png"/></svg:svg></span></span> is independent of pressure over the pressure range
100–1000 mbar in air. <span class="inline-formula">CH<sub>3</sub>O<sub>2</sub></span> was generated in HIRAC using either
the photolysis of <span class="inline-formula">Cl<sub>2</sub></span> with UV black lamps in the presence of <span class="inline-formula">CH<sub>4</sub></span> and <span class="inline-formula">O<sub>2</sub></span> or the photolysis of acetone at 254 nm in the presence of <span class="inline-formula">O<sub>2</sub></span>. At 1000 mbar of synthetic air the correlation plot of
[<span class="inline-formula">CH<sub>3</sub>O<sub>2</sub></span>]<span class="inline-formula"><sub>FAGE</sub></span> against [<span class="inline-formula">CH<sub>3</sub>O<sub>2</sub></span>]<span class="inline-formula"><sub>CRDS</sub></span> gave a
gradient of <span class="inline-formula">1.09±0.06</span>. At 100 mbar of synthetic air the FAGE–CRDS correlation plot had a gradient of <span class="inline-formula">0.95±0.024</span>, and at 80 mbar of
<span class="inline-formula">3:1</span> <span class="inline-formula">He∕O<sub>2</sub></span> mixture the correlation plot gradient was <span class="inline-formula">1.03±0.05</span>.
These results provide a validation of the FAGE method to determine
concentrations of <span class="inline-formula">CH<sub>3</sub>O<sub>2</sub></span>.</p>
Abstract This study describes the numerical analyses performed to investigate the bearing capacity of strip footings placed on granular (frictional) material overlying soft clay subjected to combined vertical-horizontal and vertical-moment loading. A plane-strain finite element limit analysis is used to estimate the limiting load combinations for two layer soil geometries where the top layer is either fully extended in the horizontal direction or it is of limited horizontal extent, representative of rock or gravel berms commonly used in offshore practice. Bearing capacity envelopes for combined vertical, horizontal and/or moment loading are well-documented in the literature for cases of footings resting on single sand or clay soil. For two-layer sand-over-clay soil with a horizontally extensive top layer, the vertical-horizontal and vertical-moment envelopes initially coincide with the envelope for a single sand layer at low vertical loads, but show an abrupt reduction in the horizontal or moment capacity as the vertical load increases beyond a certain critical vertical load. The critical vertical load is found to vary as a function of the thickness and the lateral extent of the upper layer. Relationships are presented to enable the vertical-horizontal and vertical-moment envelopes to be estimated based on the problem geometry and material properties. The findings in this study provide insight into the response of subsea foundations placed on rock or gravel of limited extent overlying a clay seabed as well as the general response of shallow foundations on two-layer profiles.
<p>Permittivity models for microwave frequencies of
liquid water below 0 <span class="inline-formula"><sup>∘</sup></span>C (supercooled liquid water) are poorly
constrained due to limited laboratory experiments and observations,
especially for high microwave frequencies. This uncertainty translates
directly into errors in retrieved liquid water paths of up to 80 %. This
study investigates the effect of different liquid water permittivity models
on simulated brightness temperatures by using the all-sky assimilation
framework of the Integrated Forecast System. Here, a model configuration with
an improved representation of supercooled liquid water has been used. The
comparison of five different permittivity models with the current one shows a
small mean reduction in simulated brightness temperatures of at most 0.15 K
at 92 GHz on a global monthly scale. During austral winter, differences
occur more prominently in the storm tracks of the Southern Hemisphere and in
the intertropical convergence zone with values of around 0.5 to 1.5 K.
Compared to the default <span class="cit" id="xref_text.1"><a href="#bib1.bibx21">Liebe</a> (<a href="#bib1.bibx21">1989</a>)</span> approach, the permittivity models
of <span class="cit" id="xref_text.2"><a href="#bib1.bibx26">Stogryn et al.</a> (<a href="#bib1.bibx26">1995</a>)</span>, <span class="cit" id="xref_text.3"><a href="#bib1.bibx24">Rosenkranz</a> (<a href="#bib1.bibx24">2015</a>)</span> and
<span class="cit" id="xref_text.4"><a href="#bib1.bibx27">Turner et al.</a> (<a href="#bib1.bibx27">2016</a>)</span> all improve fits between observations and all-sky
brightness temperatures simulated by the Integrated Forecast System. In
cycling data assimilation these newer models also give small improvements in
short-range humidity forecasts when measured against independent
observations. Of the three best-performing models, the
<span class="cit" id="xref_text.5"><a href="#bib1.bibx26">Stogryn et al.</a> (<a href="#bib1.bibx26">1995</a>)</span> model is not quite as beneficial as the other two,
except at 183 GHz. At this frequency, <span class="cit" id="xref_text.6"><a href="#bib1.bibx24">Rosenkranz</a> (<a href="#bib1.bibx24">2015</a>)</span> and
<span class="cit" id="xref_text.7"><a href="#bib1.bibx27">Turner et al.</a> (<a href="#bib1.bibx27">2016</a>)</span> look worse because they expose a scattering-related
forward model bias in frontal regions. Overall, <span class="cit" id="xref_text.8"><a href="#bib1.bibx24">Rosenkranz</a> (<a href="#bib1.bibx24">2015</a>)</span> is
favoured due to its validity up to 1 THz, which will support future
submillimetre missions.</p>
Сучасна Україна потребує розширення сфери застосування систем пневмоавтоматики в машинобудуванні (машини ударної дії, затискні пристрої та подача робочого інструменту у верстатах, роботи-маніпулятори, приводи пневматичних домкратів, ручний механізований інструмент) і автомобілебудуванні (пневматичні амортизатори, системи відкривання дверей).
Як гідравлічний так і пневматичний приводи широко застосувуюится на підйомно-транспортних, будівельних, дорожніх, меліоративних машинах, а також на технологічних лініях підприємств, які виготовляють продукцію різних галузей промисловості.
В статті наведені теоретичні основи роботи пневмоприводів та представлений опис конструкції, призначення існуючих елементів пневмосистем і елементів керування пневмосистемами. Розглянуто приклади використання цих елементів на пневмостенді виробництва компанії CAMOZZI та змодельовано принцип їх роботи в програмі FluidSim. Пневмоциліндри на навчальних стендах використовуються як виконавчі органи для реалізації поставлених задач, тому дослідження взаємодії найбільш розповсюджених елементів таких як реле часу, дроселі, різноманітні клапани та розподільники є важливим аспектом при роботі з пневматичними системами та виконання задач автоматичного регулювання процесів руху виконавчих органів.
Досліджено вплив налаштування елементів пневмосистеми на швидкість руху та порядок роботи двох пневомоциліндрів двосторонньої дії з використанням пневматичного реле часу і датчиків положення. При роботі стенда реле часу замінювала система складена з дроселю, одностороннього пневмоциліндра і моностабільного розподільника 3/2. Шляхом регулювання дроселя було досягнуто витримку в часі між висуванням штоку пневмоциліндра 1 та штоку пневмоциліндра 2.
На монтажній плиті пневмостенда (мехатронного стенда) реалізовано пневматичну систему за складеною пневматичною схемою, як виконавчий орган використано два пневмоциліндри двосторонньої дії.
Проведені випробування роботи двох пневмоциліндрів двосторонньої дії та одного пневмоциліндра односторонньої дії, який виконував роль ресивера в реле часу. Досліджено параметри, які потрібно враховувати при проектуванні пневмосистем.
<p>Aerosol volume size distribution (VSD) retrievals from the Aerosol Robotic Network (AERONET) aerosol monitoring network were obtained during multiple DRAGON (Distributed Regional Aerosol Gridded Observational Network) campaigns conducted in Maryland, California, Texas and Colorado from 2011 to 2014. These VSD retrievals from the field campaigns were used to make comparisons with near-simultaneous in situ samples from aircraft profiles carried out by the NASA Langley Aerosol Group Experiment (LARGE) team as part of four campaigns comprising the DISCOVER-AQ (Deriving Information on Surface conditions from Column and Vertically Resolved Observations Relevant to Air Quality) experiments. For coincident (<span class="inline-formula">±1</span> h) measurements there were a total of 91 profile-averaged fine-mode size distributions acquired with the LARGE ultra-high sensitivity aerosol spectrometer (UHSAS) instrument matched to 153 AERONET size distributions retrieved from almucantars at 22 different ground sites. These volume size distributions were characterized by two fine-mode parameters, the radius of peak concentration (<span class="inline-formula"><i>r</i><sub>peak_conc</sub></span>) and the VSD fine-mode width (width<span class="inline-formula"><sub>peak_conc</sub></span>). The AERONET retrievals of these VSD fine-mode parameters, derived from ground-based almucantar sun photometer data, represent ambient humidity values while the LARGE aircraft spiral profile retrievals provide dried aerosol (relative humidity; RH <span class="inline-formula"><20</span> %) values. For the combined multiple campaign dataset, the average difference in <span class="inline-formula"><i>r</i><sub>peak_conc</sub></span> was <span class="inline-formula">0.033±0.035</span> <span class="inline-formula">µm</span> (ambient AERONET values were 15.8 % larger than dried LARGE values), and the average difference in width<span class="inline-formula"><sub>peak_conc</sub></span> was <span class="inline-formula">0.042±0.039</span> <span class="inline-formula">µm</span> (AERONET values were 25.7 % larger). For a subset of aircraft data, the LARGE data were adjusted to account for ambient humidification. For these cases, the AERONET–LARGE average differences were smaller, with <span class="inline-formula"><i>r</i><sub>peak_conc</sub></span> differing by <span class="inline-formula">0.011±0.019</span> <span class="inline-formula">µm</span> (AERONET values were 5.2 % larger) and width<span class="inline-formula"><sub>peak_conc</sub></span> average differences equal to <span class="inline-formula">0.030±0.037</span> <span class="inline-formula">µm</span> (AERONET values were 15.8 % larger).</p>