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Number of results: 28
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Abstract

The dedicated gravity satellite missions, in particular the GRACE (Gravity Recovery and Climate Experiment) mission launched in 2002, provide unique data for studying temporal variations of mass distribution in the Earth’s system, and thereby, the geometry and the gravity field changes of the Earth. The main objective of this contribution is to estimate physical height (e.g. the orthometric/normal height) changes over Central Europe using GRACE satellite mission data as well as to analyse them and model over the selected study area. Physical height changes were estimated from temporal variations of height anomalies and vertical displacements of the Earth surface being determined over the investigated area. The release 5 (RL05) GRACE-based global geopotential models as well as load Love numbers from the Preliminary Reference Earth Model (PREM) were used as input data. Analysis of the estimated physical height changes and their modelling were performed using two methods: the seasonal decomposition method and the PCA/ EOF (Principal Component Analysis/Empirical Orthogonal Function) method and the differences obtained were discussed. The main findings reveal that physical height changes over the selected study area reach up to 22.8 mm. The obtained physical height changes can be modelled with an accuracy of 1.4 mm using the seasonal decomposition method.
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Authors and Affiliations

Małgorzata Szelachowska
Jan Krynski
Walyeldeen Godah
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Abstract

In the paper a transformation between two height datums (Kronstadt’60 and Kronstadt’86, the latter being a part of the present National Spatial Reference System in Poland) with the use of geostatistical method – kriging is presented. As the height differences between the two datums reveal visible trend a natural decision is to use the kind of kriging method that takes into account nonstationarity in the average behavior of the spatial process (height differences between the two datums). Hence, two methods were applied: hybrid technique (a method combining Trend Surface Analysis with ordinary kriging on least squares residuals) and universal kriging. The background of the two methods has been presented. The two methods were compared with respect to the prediction capabilities in a process of crossvalidation and additionally they were compared to the results obtained by applying a polynomial regression transformation model. The results obtained within this study prove that the structure hidden in the residual part of the model and used in kriging methods may improve prediction capabilities of the transformation model.
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Authors and Affiliations

Marcin Ligas
Marek Kulczycki
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Abstract

In this study, several variants create and choose of a local quasi-geoid model in Poland have been considered. All propositions have a source in European Gravimetric Geoid models – EGG2008 and EGG2015, which are purely gravimetric models of reference surface. In the course of this work, each model has been analyzed in various ways: without any corrections, by parallel shifting of residuals, by the 7-parameter conformal transformation and by fitting residuals by 4- and 5-parameter trigonometric polynomials. Eventual corrections were based on points of national GNSS/levelling networks (EUVN, EUVN_DA, POLREF, EUREF and ASG-EUPOS eccentric points). As a final result of this study, a comparison of the accuracy of selected models has been carried out by RMSE statistics and maps showing spatial distribution of residuals and histograms. Validation has shown that the maximum achievable accuracy of the EGG models is approximately 2 cm for the ETRF2000 reference system and approximately 8 cm for ETRF89. In turn, fitting with the use of different mathematical methods results in an improvement of the standard deviation of residues to the level of 1.3–1.4 cm. The conclusions include an evaluation of considerations for and against the use of models based only on EGG realizations and, on the other hand, fitted to the points of Polish vertical network. Its usefulness is strictly connected with needs of the definition of up to date quasi-geoid model for the new realization of heights system in Poland, based on EVRF2007 frame.

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Authors and Affiliations

Dorota Marjańska
Tomasz Olszak
Dominik Piętka
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Abstract

Applications in geodesy and engineering surveying require the determination of the heights of the vertical control points in the national and local networks using different techniques. These techniques can be classified as geometric, trigonometric, barometric and Global Positioning System (GPS) levelling. The aim of this study is to analyse height differences obtained from these three techniques using precise digital level and digital level, total station (trigonometric levelling) and GPS which collects phase and code observations (GPS levelling). The accuracies of these methods are analysed. The results obtained show that the precise digital levelling is more stable and reliable than the other two methods. The results of the three levelling methods agree with each other within a few millimetres. The different levelling methods are compared. Geometric levelling is usually accepted as being more accurate than the other methods. The discrepancy between geometric levelling and short range trigonometric levelling is at the level of 8 millimetres. The accuracy of the short range trigonometric levelling is due the reciprocal and simultaneous observations of the zenith angles and slope distances over relative short distances of 250 m. The difference between the ellipsoidal height differences obtained from the GPS levelling used without geoid and the orthometric height differences obtained from precise geometric levelling is 4 millimetres. The geoid model which is obtained from a fifth order polynomial fit of the project area is good enough in this study. The discrepancy between the precise geometric and GPS levelling (with geoid corrections) is 4 millimetres over 5 km.

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Authors and Affiliations

Atınç Pırtı
Ramazan Gürsel Hoşbaş
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Abstract

Time series of weekly and daily solutions for coordinates of permanent GNSS stations may indicate local deformations in Earth’s crust or local seasonal changes in the atmosphere and hydrosphere. The errors of the determined changes are relatively large, frequently at the level of the signal. Satellite radar interferometry and especially Persistent Scatterer Interferometry (PSI) is a method of a very high accuracy. Its weakness is a relative nature of measurements as well as accumulation of errors which may occur in the case of PSI processing of large areas. It is thus beneficial to confront the results of PSI measurements with those from other techniques, such as GNSS and precise levelling. PSI and GNSS results were jointly processed recreating the history of surface deformation of the area of Warsaw metropolitan with the use of radar images from Envisat and Cosmo- SkyMed satellites. GNSS data from Borowa Gora and Jozefoslaw observatories as well as from WAT1 and CBKA permanent GNSS stations were used to validate the obtained results. Observations from 2000–2015 were processed with the Bernese v.5.0 software. Relative height changes between the GNSS stations were determined from GNSS data and relative height changes between the persistent scatterers located on the objects with GNSS stations were determined from the interferometric results. The consistency of results of the two methods was 3 to 4 times better than the theoretical accuracy of each. The joint use of both methods allows to extract a very small height change below the level of measurement error.
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Authors and Affiliations

Jan Krynski
Lukasz Zak
Dariusz Ziolkowski
Jan Cisak
Magdalena Lagiewska
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Abstract

The choice of global geopotential model used in remove-restore technique for determination of regional quasi geoid from gravity data may affect the solution, in particular when the accuracy is supposed to reach a centimetre level. Global geopotential model plays also an important role in validating height anomalies at GPS/levelling sites that are used for the estimation of the external accuracy of quasigeoid models. Six different global geopotential models are described in the paper. Three kinds of numerical tests with use of terrestrial gravity data and GPS/levelling height anomalies were conducted. The first one concerned comparison of height anomalies at GPS/levelling sites ia Poland with corresponding ones computed from various global geopotential models. In the second one the terrestrial gravity anomalies in Poland and neighbouring countries were compared with corresponding gravity anomalies computed from global geopotential models. Finally the quasigeoid models obtained from gravity data with use of different global geopotential models were verified against corresponding height anomalies at GPS/levelliag sites in Poland. Data quality was discussed and best fitting global geopotential model in Poland was specified.
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Authors and Affiliations

Jan Kryński
ORCID: ORCID
Adam Łyszkowicz
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Abstract

In this work studies of barrier height local values are presented. Distribution of the gate-oxide EBG(x, y) and semiconductor-oxide EBS(x, y) barrier height local values have been determined using the photoelectric measurement methods. Two methods were used to obtain the local values of the barrier heights: modified Powell-Berglund method and modified Fowler method. Both methods were modified in such a way as to allow determination of the EBG(x, y) and EBS(x, y) distribution over the gate area using a focused UV light beam of a small diameter d = 0.3 mm. Measurements have been made on a series of Al-SiO2-Si(n+) MOS structures with semitransparent (tAl = 35 nm) square aluminum gate (1 x 1 mm2). It has been found that the EBG(x, y) distribution has a characteristic dome-like shape, with highest values at the center of the gate, lower at the gate edges and still lower at gate corners. On the contrary, the EBS(x, y) distribution is of a random character. Also, in this paper, both barrier height measurements have been compared with the photoelectric effective contact potential difference fMS(x, y) measurements. These results show good agreement between distribution of the barrier heights EBG(x, y) and EBS(x, y) measurements and independently determined shape of the effective contact potential difference fMS(x, y) distribution.

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Authors and Affiliations

K. Piskorski
H.M. Przewlocki
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Abstract

The paper presents results of a research on simulation of magnetic tip-surface interaction as a function of the lift height in the magnetic force microscopy. As expected, magnetic signal monotonically decays with increasing lift height, but the question arises, whether or not optimal lift height eventually exists. To estimate such a lift height simple procedure is proposed in the paper based on the minimization of the fractal dimension of the averaged profile of the MFM signal. In this case, the fractal dimension serves as a measure of distortion of a pure tip-surface magnetic coupling by various side effects, e.g. thermal noise and contribution of topographic features. Obtained simulation results apparently agree with experimental data.

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Authors and Affiliations

M. Bramowicz
S. Kulesza
T. Chrostek
C. Senderowski
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Abstract

As the impact of global climate change increases, the interaction of biotic and abiotic stresses increasingly threatens current agricultural practices. The most effective solution to the problem of climate change and a decrease in the amount of atmospheric precipitation is planting extremely drought-resistant and high-yielding crops. Sorghum can grow in harsh conditions such as salinity, drought and limited nutrients, also it is an important part of the diet in many countries. Sorghum can be introduced in many zones of Kazakhstan. Plant height and yield of green plant biomass of 16 sorghum samples in arid conditions were determined based on a set of agrobiological characteristics for field screening. The height of the studied samples of grain sorghum was 0.47 ±0.03 m, and the height of sweet sorghum was much longer, reaching up to 2.88 ±0.12 m. Also, there was a strong difference in green biomass in cultivated areas under different soil and climatic conditions, the green biomass of sweet sorghum was 3.0 Mg∙ha –1, and in grain sorghum, it reached up to 57.4 Mg∙ha –1. Based on the data of the field assessment for various soil and climatic conditions, the following samples were identified for introduction into production: samples of sweet sorghum for irrigated and rainfed lands of the Almaty Region and in the conditions of non-irrigation agriculture of the Aktobe Region – a promising line ICSV 93046. For non-irrigation agriculture of the Akmola Region, genotypes of sweet and grain sorghum are ‘Chaika’, ‘Kinelskoe 4’ and ‘Volzhskoe 44’.
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Authors and Affiliations

Rauan Zhapayev
1
Kristina Toderich
2 3
Gulya Kunypiyaeva
1
Meruyert Kurmanbayeva
4
Mustafa Mustafayev
5
ORCID: ORCID
Zhumagali Ospanbayev
1
Aiman Omarova
1
Adil Kusmangazinov
4

  1. Kazakh Research Institute of Agriculture and Plant Growing, Laboratory of Agriculture, Erlepesov St, 1, 040909, Almalybak, Kazakhstan
  2. International Platform for Dryland Research and Education, Tottori University, Tottori, Japan
  3. International Center for Biosaline Agriculture (ICBA), Dubai, UAE
  4. Al-Farabi Kazakh National University, Department of Biodiversity and Bioresources, Almaty, Kazakhstan
  5. Azerbaijan National Academy of Science, Institute of Soil Science and Agrochemistry, Baku, Azerbaijan
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Abstract

The influence of a fixed adsorption bed height on the adsorption process was studied using acetone, ethyl acetate, toluene, and n-butyl acetate as a gaseous adsorbate mixture. All experiments were conducted under the same gas flow and temperature conditions. Concentrations of adsorbates were monitored using gas chromatography with a flame ionization detector. Activated carbon WG-12 (Grand Activated Sp. z o.o) was selected as the adsorbent, and the following heights of the fixed adsorption bed were used: 0.8, 1.6, 3.2, and 4.8 cm. The results of the study allowed to deduce that as the height of the fixed adsorption bed increased, the degree of displacement of adsorbate molecules from the bed strengthened. In addition, it was found that both the bed breakthrough time increased linearly with a height rise of the fixed adsorption bed. The process carried out on a fixed adsorption bed with a height of 0.8 cm was characterized by an undeveloped mass transfer zone, as well as the complete displacement of the most volatile components (acetone and ethyl acetate). The utilization rate of the fixed adsorption bed also increased as the height of the adsorption bed went up. However, at a certain bed height, the bed breakthrough curves were formed and the adsorption capacity did not change significantly, solely the bed breakthrough time increased.
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Authors and Affiliations

Martyna Jurkiewicz
1
ORCID: ORCID
Marlena Musik
1
ORCID: ORCID
Robert Pełech
1
ORCID: ORCID

  1. West Pomeranian University of Technology in Szczecin, Faculty of Chemical Technology and Engineering, Department of Chemical Organic Technology and Polymeric Materials, Pułaskiego 10, 70-322 Szczecin, Poland
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Abstract

In the process of coal extraction, a fractured zone is developed in the overburden above the goaf. If

the fractured zone is connected with an aquifer, then water inrush may occur. Hence, research and analysis

of the height of overburden fractured zone (HOFZ) are of considerable significance. This study focuses

on the HOFZ determination in deep coal mining. First, general deformation failure characteristics of

overburden were discussed. Second, a new method, numerical simulation by orthogonal design(NSOD),

have been proposed to determinate the HOFZ in deep coal mining. Third, the validity of NSOD is verified

in the practical application, compared with empiric al formula in Chinese Regulations and in-situ test.

These three methods were applied to determine the HOFZ of working face No. 111303 in No. 5 coal

mine. The pre dicted HOFZ of NSOD is found to be similar to the result of the in-situ test (8.9% relative

error), whereas the HOFZ calculated by the empirical formula has extremely large error (25.7% relative

error). Results show that the NSOD can reliably predict the HOFZ in deep coal mining and reduce time

and expenses required for in-situ test.

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Authors and Affiliations

Han Yangchun
Cheng Jiulong
Huang Qisong
Zou D.H. Steve
Zhou Jin
Huang Shaohua
Long Yun
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Abstract

The GOCE (Gravity Field and Steady-State Ocean Circulation Explorer) has significantly upgraded the knowledge on the Earth gravity field. In this contribution the accuracy of height anomalies determined from Global Geopotential Models (GGMs) based on approximately 27 months GOCE satellite gravity gradiometry (SGG) data have been assessed over Poland using three sets of precise GNSS/levelling data. The fits of height anomalies obtained from 4th release GOCE-based GGMs to GNSS/levelling data were discussed and compared with the respective ones of 3rd release GOCE-based GGMs and the EGM08. Furthermore, two highly accurate gravimetric quasigeoid models were developed over the area of Poland using high resolution Faye gravity anomalies. In the first, the GOCE-based GGM was used as a reference geopotential model, and in the second – the EGM08. They were evaluated with GNSS/levelling data and their accuracy performance was assessed. The use of GOCE-based GGMs for recovering the long-wavelength gravity signal in gravimetric quasigeoid modelling was discussed.
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Authors and Affiliations

Walyeldeen Godah
Jan Krynski
Małgorzata Szelachowska
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Abstract

The summary of research activities concerning gravity field modelling and gravimetric works performed in Poland in the period of 2011–2014 is presented. It contains the results of research on geoid modelling in Poland and other countries, evaluation of global geopotential models, determination of temporal variations of the gravity field with the use of data from satellite gravity space missions, absolute gravity surveys for the maintenance and modernization of the gravity control in Poland and overseas, metrological aspects in gravimetry, maintenance of gravimetric calibration baselines, and investigations of the non- tidal gravity changes. The bibliography of the related works is given in references.
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Authors and Affiliations

Jan Krynski
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Abstract

Arbuscular mycorrizal (AM) fungi may enhance plant growth and polyphenol production, however, there have been limited studies on the relationships between root colonization of different fungal species and polyphenol production on cultivated Allium porrum (garden leek). The effects of inoculation of AM fungi spores from Rhizophagus intraradices, Giga -spora margarita, Glomus geosporum, Paraglomus occultum, Claroideoglomus claroideum, and Glomus species on colonization of garden leek roots and symbiotic changes in polyphenol production and plant growth were evaluated in greenhouse experiments. There were significant differences (p < 0.05) in colonization of leek roots by AM fungi species. The greatest level of root colonization was recorded on plants inoculated with R. intraradices (73%) and the lowest level on C. claroideum (3.2%). Significant differences (p < 0.05) in plant height were recorded between AM inoculated plants and the controls. Polyphenol levels differed significantly (p < 0.05) between garden leek plants inoculated with AM fungi and the non-inoculated controls. The percentage increases in polyphenol (a derivative of kaempferol) on garden leeks inoculated with G. geosporum relative to the untreated controls ranged from 28 to 1123%. Due to symbiosis with different AM species, other polyphenols decreased in some instances (negative values) and increased in others for values of up to 590%. Results showed that AM fungi species exhibited remarkable differences in polyphenol levels in garden leeks. The high polyphenol production by garden leek plants inoculated with G. geosporum, and Glomus species could be exploited for enhanced resistance of garden leeks to insects and diseases. This research highlights an understudied area, notably the relationships between AM fungal inoculations, root colonizations and polyphenol production in garden leeks. The findings can be utilized to improve pest resistance and the quality of garden leek plants.
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Authors and Affiliations

Ocen Modesto Olanya
Nasir Malik S.A.
Alberto Nuńez
Lindsay C. McKeever
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Abstract

For over two decades, an essential information about global monthly gravity variations is provided by the GRACE mission and its successor, the GRACE Follow-On (GRACE-FO) mission. The temporal variations in gravity field from GRACE/GRACEFO are determined based on the measurement of distance changes between two identical satellites using microwave ranging instruments. This process is carried out by various processing centers, which adopt different processing strategies and background models. This causes discrepancies in the resulting gravity fields.We address this problem by determining a monthly homogenous GRACE-FO gravity field solutions from June 2018 to November 2022 as provided by different processing centers included in the Science Data System (SDS) project, i.e. the Center for Space Research (CSR), the German Research Center for Geosciences (GFZ) and the Jet Propulsion Laboratory (JPL). We test three different weighting schemes. We show that for the last 4 years, at least 65% of continental areas are characterized by water decrease. We show that proposed merged solutions contain more signal information than individual ones based on the square root of the degree variance values.We note that the largest signal differences between individual and combined solutions occur for sectoral coefficients up to degree 40, and for zonal coefficients, the signal differences are twice as small.We also present that the differences in the spherical harmonic coefficients cause differences in global and local equivalent water height (EWH) changes. For example, the proposed merged solutions reduce root mean square scatter ofEWHby 5–15% comparing to individual solutions.
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Authors and Affiliations

Artur Lenczuk
1
ORCID: ORCID
Anna Klos
1
ORCID: ORCID
Janusz Bogusz
1
ORCID: ORCID

  1. Military University of Technology, Warsaw, Poland
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Abstract

Calculation of the effect of topography on the observed gravity becomes particularly important when modelling high-precision geoid. It requires a digital terrain model of appropriate resolution and accuracy. Various global, regional and local digital terrain models of different accuracy and resolution are recently available. Evaluation of the DTM used is required for verification and validation of its quality as well as for estimating accuracy of geoid model derived with considering the effect of topographic masses. Two DTMs: the SRTM3 of 3" x 3" resolution and the national DTM for Poland of l" x l" or l" x 2" resolution - called DTED2 - were evaluated with use of high-resolution local DTMs developed using digital photogrammetry of 25 m x 25 m as well as the regional model in Tatra mountains of 10 m x 10 m. Then the heights of almost 1000 GPS/levelling stations of Polish geodetic control were compared with the heights from the DTED2 model. The heights of over a million of gravity stations from gravity database, that were the basis of previous geoid modelling in Poland, were also compared with the heights from the DTED2 model. The effect of uncertainty of a DTM on estimation of mean gravity anomalies was discussed. In particular, the effect of replacing heights from gravity database with the heights from the DTED2 model in the process of calculating mean gravity anomalies, on the accuracy of geoid modelling was investigated. The use of the DTED2 model is at present recommended for determination of precise geoid model in Poland.
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Authors and Affiliations

Jan Kryński
ORCID: ORCID
Magdalena Mank
Małgorzata Grzyb
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Abstract

Providing roughness is an effective method to heat fluids to high temperature. Present paper make use of concave dimple roughness on one and three sides of roughened ducts aimed at determining rise in heat transfer and friction of three sides over one side roughened duct. Three sides roughened duct produces high heat transfer compared to one side roughened. Results are shown as a rise in Nusselt number and friction factor of three sides over one side roughened duct. Experimental investigation was conducted under actual outdoor condition at National Institute of Technology Jamshedpur, India to test various sets of roughened collectors. Roughness parameter varied as relative roughness pitch 8–15, relative roughness height 0.018–0.045, dimple depth to diameter ratio 1–2, Reynolds number 2500–13500 at fixed aspect ratio (width/hight) 8. Highest enhancement in Nusselt number for varying relative roughness pitch, height, and diameter ratio was respectively found as 2.6 to 3.55 times, 1.91 to 3.42 times and 3.09 to 3.94 times compared to one side dimple roughened duct. Highest rise in friction for three sides over one side roughened duct for these varying parameters was respectively found as 1.62 to 2.79 times, 1.52 to 2.34 times and 2.21 to 2.56 times. To visualize the effect of roughness parameter on heat transfer and friction factor, variation in Nusselt number and friction factor for varying roughness parameters with Reynolds number is shown.

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Authors and Affiliations

Vikash Kumar
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Abstract

The present paper describes the experimental analysis of heat transfer and friction factor for glass protected three-side artificially roughened rectangular duct solar air heaters (SAHs) having an arrangement of multiple-v and transverse wires (top wall multi-v and two side walls transverse) under the absorber plate, and compares their performance with that of one-side roughened solar air heaters under similar operating conditions. The investigated three-side solar air heaters are characterized by a larger rate of heat transfer and friction factor as compared to one-side artificially roughened SAHs by 24–76% and 4–36%, respectively, for the identical operating parameters. The air temperature below the three-side rugged duct is by 34.6% higher than that of the one-side roughened duct. Three-side solar air heaters are superior as compared to one-side artificially roughened solar air heaters qualitatively and quantitatively both.
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Authors and Affiliations

Dhananjay Kumar
1

  1. B.A. College of Engineering and Technology, Ghutia, P.O. Barakhurshi Jamshedpur, Jharkhand 832304, India
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Abstract

New solutions in plant protection applications are still highly desirable. Aiming at higher efficiency, environmental safety and profitability of production which, in addition to reducing the costs of the application of plant protection products, limits the destruction of soil structure combined use of agrochemicals seems to be one of the most important method in modern agriculture. In 2016 and 2017, the Plant Protection Institute – National Research Institute in Poznań, Poland, conducted field experiments on the possibility of combining two popular herbicides used to control monocotyledonous weeds: pinoxaden and fenoxaprop-P-ethyl, with a two-component plant growth and development regulator (mepiquat chloride and prohexadione calcium) on KWS Ozon winter wheat. The tested substances were applied at the BBCH 24 stage of winter wheat – herbicide only, and at the BBCH 31 stage – a mix of herbicides with a plant growth and development regulator. Regardless of the method of application of pinoxaden (herbicide only or mixed), high effectiveness of Apera spica-venti control was obtained in both years of the study. The mix of pinoxaden with mepiquat chloride and prohexadione calcium reduced the wheat crop height to a similar extent as separate application of the substances. The combined application of fenoxaprop-P-ethyl with mepiquat chloride improved the effectiveness of wheat crop height control. The method of application of the substances had no significant effect on winter wheat yield. Grain yields harvested from plots treated with the above substances were significantly higher than control only in the case of high weed infestation of winter wheat. The technological value of wheat grain depended on the year of study, while the method of application did not have a significant impact on the evaluated parameters.

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Authors and Affiliations

Wojciech Miziniak
Kinga Matysiak
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Abstract

In this study, direct shear tests were carried out on cement mortar specimens with singleladder, single-rectangular, and double-rectangular step joints. Consequently, the shear strength, and crack shape of specimens with these through-step joints were analyzed, for understanding the influence of the through-step joint’s shape on the direct shear mechanical properties. The results of the investigation are as follows: (1) Under the same normal stress, any increases in the height ℎ of the step joint causes an initial-increase-decrease in the shear strengths of specimens with single-ladder and double-rectangular step joints, causing a type-Wvariation pattern for the specimens with single-rectangular step joint. More essentially, when normal stress and ℎ are constant, the shear strength of specimens with a single-ladder step joint is the greatest, followed by specimens with a double-rectangular step joint, and then specimens with a single-rectangular step joint is the least. (2) Furthermore, given a smallℎ and low normal stress, specimen with a single-ladder step joint mainly experiences shear failure, whereas specimens with single-rectangular and double-rectangular step joints mainly generate extrusion milling in the step joints.
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Authors and Affiliations

Liangxiao Xiong
1
ORCID: ORCID
Haijun Chen
2
ORCID: ORCID
Haogang Guo
3
ORCID: ORCID
Songhua Mei
1
ORCID: ORCID
Zhongyuan Xu
4
ORCID: ORCID
Bin Liu
5
ORCID: ORCID

  1. Hunan Provincial Key Laboratory of Hydropower Development Key Technology, Power China Zhongnan Engineering Corporation Limited, Changsha 410014, China
  2. Geotechnical Engineering Department, Nanjing Hydraulic Research Institute, Nanjing, 210029, China
  3. Civil and Environmental Engineering Department, Carnegie Mellon University, Pittsburgh 15289, United States
  4. Faculty of Geosciences and Environmental Engineering, Southwest Jiaotong University, Chengdu 611756, China
  5. School of Civil Engineering and Architecture, East China Jiaotong University, Nanchang 330013, China
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Abstract

The aim of the paper is to shed light on the theoretical background of the inclusion of health in the standard of living studies, and the use of two of its specifi c measures — life expectancy at birth and body height. Hence, the article describes the idea of capabilities and functionings developed by Amartya Sen as a proposed solution to the limitations of the classic measurement of the standard of living.

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Authors and Affiliations

Bartosz Ogórek
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Abstract

An uniaxial compression mechanical model for the roof rock-coal (RRC) composite sample was established in order to study the effects of height ratio of roof rock to coal on the structural strength of composite sample. The composite sample strengths under different height ratios were established through stress and strain analysis of the sample extracted from the interface. The coal strength near the interface is enhanced and rock strength near the interface weakened. The structural strength of composite sample is synthetically determined by the strengths of rock and coal near and far away from the interface. The area with a low strength in composite sample is destroyed firstly. An analytical model was proposed and discussed by conducting uniaxial compression tests for sandstone-coal composite samples with different height ratios, and it was found that the structural strength and elastic modulus decrease with a decrease in height ratio. The coal strengths far away from the interface determine the structural strengths of composite sample under different height ratios, which are the main control factor for the structural strength in this test. Due to its lowest strength, the rock near the interface first experienced a tensile spalling failure at the height ratio of 9:1, without causing the structural failure of composite sample. The coal failure induces the final failure of composite sample.

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Authors and Affiliations

Dawei Yin
Shaojie Chen
Xizhen Sun
Ning Jiang
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Abstract

The deformation and failure law of stope roofs is more complicated than horizontal coal seams affected by the angle of the coal seam during the mining process of steeply dipping coal seams. This study focused on and analysed the working face of a 2130 coal mine with steep dipping and large mining height. Through the use of numerical calculation, theoretical analysis, physical similar material simulation experiments, and field monitoring, the distribution characteristics of roof stress, as well as the threedimensional caving migration and filling law, in large mining height working faces under the dip angle effect was investigated. The influence mechanism of the dip angle change on the roof stability of large mining heights was investigated. The results revealed that the roof stress was asymmetrically distributed along the inclination under the action of the dip angle, which resulted in roof deformation asymmetry. With the increase in the dip angle, the rolling and sliding characteristics of roof-broken rock blocks were more obvious. The length of the gangue support area increased, the unbalanced constraint effect of the filling gangue on the roof along the dip and strike was enhanced, and the height of the caving zone decreased. The stability of the roof in the lower inclined area of the working face was enhanced, the failure range of the roof migrated upward, and the damage degree of the roof in the middle and upper areas increased. Furthermore, cross-layer, large-scale, and asymmetric spatial ladder rock structures formed easily. The broken main roof formed an anti-dip pile structure, and sliding and deformation instability occurred, which resulted in impact pressure. This phenomenon resulted in the dumping and sliding of the support. The ‘support-surrounding rock’ system was prone to dynamic instability and caused disasters in the surrounding rock. The field measurement results verified the report and provided critical theoretical support for field engineering in practice.
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Authors and Affiliations

Panshi Xie
1 2
Baofa Huang
1 2
Yongping Wu
1 2
ORCID: ORCID
Shenghu Luo
2 3
ORCID: ORCID
Tong Wang
1 2
ORCID: ORCID
Zhuangzhuang Yan
1 2
Jianjie Chen
4

  1. Xi’an University of Science and Technology, School of Energy Engineering, Xi’an 710054, China
  2. Xi’an University of Science and Technology, Key Laboratory of Western Mine Exploitation and Hazard Prevention Ministry of Educat ion, Xi’an 710054, China
  3. Xi’an University of Science and Technology, Department of Mechanics, Xi’an, 710054, China
  4. Xinjiang Coking Coal Group Corporat ion Limited, Xinjiang 830025, China

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