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1

Research on sand resistance performance of comprehensive protection facilities for desert hinterland highways under strong wind environment

Yin Wenhua, Wang Xu, Wu Yongxiang, Wang Fang

Archives of Civil Engineering

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2022

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Vol. 68, nr 4

683--698

EN

Based on the test and observation of the desert hinterland wind field, combined with the numerical simulation of Fluent wind-sand two-phase flow, the sand resistance performances of comprehensive protection in the desert hinterland under strong wind environment are researched. The transient wind speed and wind direction around the comprehensive protection facility are measured by two 3D ultrasonic anemometers on the highway in the desert hinterland, and the initial wind speed of the sand flow is provided for the numerical simulation boundary. The sedimentary sand particles around the comprehensive protection facility are collected for particle size analysis, and the particle size distributions of sedimentary sand particles at different locations are obtained. Numerical models of high vertical sand barriers, grass checkered sand barriers and roadbeds are established by Fluent, the wind-sand flow structures around the comprehensive protection facilities and desert hinterland highway under the strong wind environment are obtained, and the influence laws of the comprehensive protection facilities on the movement of wind-sand flow and sand deposition characteristics are obtained. The study found that the comprehensive protection facilities disturbed the wind and sand flow, and there are significant airflow partitions around the comprehensive protection facilities. The wind speed decreases rapidly after the wind-sand flows through the high vertical sand barrier; the wind-sand flow rises at the end of the high vertical sand barrier. When the wind-sand flow moves around the grass checkered sand barrier, the wind speed has dropped to the range of 0-3 m/s, and the wind speed near the ground by the grass checkered sand barrier is further reduced. Due to the existence of the concave surface of the grass grid, there are small vortices inside the grass grid sand barrier. Large sand particles are mainly deposited on the windward side and inside of high vertical sand barriers. The grass checkered sand barrier forms a stable concave surface to generate backflow, which can ensure that the sand surface does not sand itself in a strong wind environment, and can also make a small amount of sand carried in the airflow accumulate around the groove of the grass checkered sand barrier. The numerical simulation results are consistent with the measured results, and the comprehensive protection measures have achieved good sand control effects.

2

Denoising of desert seismic signal based on synchrosqueezing transform and Adaboost algorithm

Sun Xiaofu, Li Yue

Acta Geophysica

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2020

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Vol. 68, no. 2

403--412

EN

Seismic data in desert area generally have low signal-to-noise ratio (SNR) due to special surface conditions. Desert noise is characterized as low-frequency, non-Gaussian and non-stationary noise, which makes the noise suppression in desert area more challenging by conventional methods. Conventional methods are efective for the signal with high SNR, but in desert seismic signal, the SNR is low and the signal can easily be obliterated in desert noise. In this paper, we propose an approach that operates in synchrosqueezing transform (SST) domain and use classifcation techniques obtained from supervised machine learning to identify the coefcients associated with signal and noise. First of all, we transform the real desert seismic data into time–frequency domain by SST. Secondly, we select features by calculating the SST coefcients of signal and noise. And then, we train them in the Adaboost classifer. Finally, when the training is completed, we can obtain the fnal classifer that can efectively separate the signal from noise. We perform tests on synthetic and feld records, and the results show great advantages in suppressing random noise as well as retaining efective signal amplitude.

3

Desert loess: a selection of relevant topics

Smalley Ian, Marshall John, Fitzsimmons Kathryn, Whalley W. Brian, Ngambi Samson

Geologos

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2019

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Vol. 25, No. 1

91--102

EN

In discussions on loess, two types are often demarcated: glacial loess and desert loess. The origin of the idea of desert loess appears to lie with V.A. Obruchev who observed wind-carried silt on the Potanin expedition to Central Asia in 1895. It might be considered that desert loess would be defined as loess associated with deserts but it came to be thought of as loess produced in deserts. This led to some controversy as no mechanism for producing silt particles in deserts was readily available. Bruce Butler in Australia in particular cast doubt on the existence of desert-made loess. Butler indicated loess-like deposits in Australia which he called Parna; these are very like loess but the silt sized particles are actually clay mineral agglomerates of silt size- formed in dry lake regions. At the heart of the desert loess discussion is the problem of producing loess material in deserts. It has been suggested that there are no realistic mechanisms for forming large amounts of loess dust but there is a possibility that sand grain impact may produce particle shattering and lead to the formation of quartz silt. This would appear to be a reasonable mechanism for the African deposits of desert loess, but possibly inadequate for the huge deposits in China and Central Asia. The desert loess in China and Central Asia is loess associated with a desert. The material is formed in cold, high country and carried by rivers to the vicinity of deserts. It progresses then from deserts to loess deposit. Adobe ground may be defined as desert loess. Adobe occurs on the fringe of deserts, notably in the Sahelian region of Africa, and in SW USA. The use of adobe in construction represents the major utilization of desert loess in a social context. More understanding of adobe is required, in particular with respect to the adobe reaction, the low order chemical reaction which provides modest cementitious properties, and can be likened to the pozzolanic reactions in hydrating cement systems. The location of loess and loess-like ground on the peripheries of deserts is aided by the observation of the nesting sites of bee-eater birds. These birds have a determined preference for loess ground to dig their nesting tunnels; the presence of nest tunnels suggests the occurrence of desert loess, in desert fringe regions. We seek amalgamation and contrast: ten main topics are considered: words and terms, particles, parna, geotechnical, adobe, people, birds, Africa, Central Asia, Mars. The aim is some large generalizations which will benefit all aspects of desert loess investigation.

4

Typowe ogrody australijskiej pustyni

Kożuszek R.

Zieleń Miejska

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2017

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Nr 5

24--26

PL

Najważniejszym aspektem w kreowaniu ogrodów pustyni jest zminimalizowanie strat wody, które w suchym klimacie potrafią być ogromne. Idealnymi przykładami na typowe ogrody pustyni są te zlokalizowane w najgorętszym i najsuchszym mieście świata – w Alice Springs w Australii.

5

Landscape values of Joshua Tree National Park

Świtalska A.

Przestrzeń i Forma

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2017

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nr 30

279--294

EN

This article presents the landscape in Joshua Tree National Park in the United States and shows the different degrees of accessibility of individual locations. Selected places in the park are described. The analysis of the number of visitors indicated whether it is worthwhile to preserve nature and to protect it. It also respond to questions relating to the need for human interaction with nature.

PL

Artykuł przedstawia krajobraz w Parku Narodowym Drzewo Jozuego w Stanach Zjednoczonych oraz ukazuje różne stopnie dostępności poszczególnych lokalizacji. Opisane zostały wybrane miejsca w parku. Analiza liczby odwiedzających wskazała, czy warto zachowywać naturę oraz ją chronić i odpowiedziała na pytania odnoszące się do potrzeby obcowania człowieka z naturą.

6

Differential effects of grazing on plant functional traits in the desert grassland

An H., Li G.

Polish Journal of Ecology

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2014

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Vol. 62, nr 2

239--251

EN

Plant functional traits are linked with environmental factors, individuals and ecosystem structure and functions as plants respond and adapt to the environment. Here, the whole-plant traits (plant height and plant biomass), leaf morphological (leaf area, leaf dry mass and specific leaf area) and chemical traits (leaf carbon, nitrogen, phosphorus contents, C/N and N/P ratio) of six dominant species (Cynanchum komarovii Al, Euphorbia esula Linn, Glycyrrhiza uralensis Fisch, Lespedeza potaninii Vass, Agropyron mongolicum Keng and Stipa breviflora Griseb) were studied in the desert grassland of China, with a grazing experiment including four grazing intensity (0.00, 0.45, 1.00, 1.50 sheep ha-1). The effect of grazing on leaf morphological traits were significant for the six dominant species, while the effects on whole-plant traits were highly significant for S. breviflora, A. mongolicum, G. uralensis, L. potaninii and C. komarovii. Three of the six species (S. breviflora, A. mongolicum and L. potaninii) decreased in plant height (PH) with increasing grazing intensity, while specific leaf area (SLA) and leaf N (Nmass) showed the opposite trend. The whole-plant traits were significantly positively correlated with leaf dry mass (LM), but significantly negatively correlated with leaf nitrogen and phosphorus contents. The first principal component analysis (PCA) axis corresponding to plant size (PH and PB) and leaf size (LA and LM), while the second axis of PCA to leaf chemical traits (Nmass, P, C and N/P). Variations of plant traits in response to grazing were mainly explained by size trait and chemical traits. The functional traits cannot be the only basis for predicting plant species in response to grazing, and a functional analysis of the trade-off between plant traits is also needed.

7

Quick sands effect on desert lands – example of filtration stability loss

Strzelecki M.

Studia Geotechnica et Mechanica

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2013

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Vol. 35, nr 1

219--218

EN

The aim of the study was to analyze the loss of filtration stability of fine desert sands due to the air flow caused by temperature difference. The loss of stability induces the effect of so called “quick sands”. Therefore, the calculations of air filtration through the loose sand medium in dry desert climate are presented. FlexPDE v.6. software was used for numerical calculation based on FEM.

8

Piaszczysto-skalista pustynia Wadi Rum w południowej Jordanii

Jarmołowicz-Szulc K.

Przegląd Geologiczny

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2009

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Vol. 57, nr 4

283-285

9

Impact of the invasive species Elaeagnus angustifolia L. on vegetation in Pontic desert steppe zone (Southern Ukraine)

Sudnik-Wójcikowska B., Moysiyenko I., Slim P., Moraczewski I.

Polish Journal of Ecology

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2009

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Vol. 57, nr 2

269-281

EN

The Irano-Turanian species - Russian olive (Elaeagnus angustifolia L.) - is one of most commonly planted tree in the shelterbelts in southern Ukraine. The consequences of introduction of the species from windbreaks, into areas of different land use in west and central Pontic desert steppe zone are evaluated. The above steppe is unique on a European scale and exists only in some parts of the Black and Azovian Sea coasts. In recent years, the socio-economical crisis in Ukraine (less intensively cultivation, as well as limited grazing) has been responsible for the intensification of the spread of alien tree species outside the windbreaks. Studies were conducted in Kherson Region, in the immediate vicinity of the Black Sea Biosphere Reserve, where the presence of aliens is undesirable. The analysis of phytosociological material (48 releves with and without Russian olive) collected from areas of different land use type and limited human pressure (as abandoned field, former intensively grazed solonetz and extensively grazed desert steppe vegetation) show that E. angustifolia can impede the regeneration of the desert steppe. The species creates favourable conditions for the growth of geographically and ecologically alien nithrophilous weeds.

10

Jordania - geoturystyczny raj

Pająk J.

Geoturystyka

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2004

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T. 1, nr 1

59-64

PL

Artykuł ten jest relacją z wyprawy studentów WGGiOŚ AGH do Jordanii, monarchii islamskiej na Półwyspie Arabskim. Graniczy ona z Syrią, Irakiem, Arabią Saudyjską, Palestyną oraz Izraelem. Kraj ten bogaty jest w różnorodne atrakcje turystyczne, związane z historią tychże obszarów, kulturą, a także szeroko pojętą geologią. Celem wyprawy było dotarcie do najciekawszych, pod względem geoturystycznym, obiektów geologicznych. Na trasie znalazły się: Morze Martwe, najniżej położone miejsce na Ziemi, Pustynia Wadi Rum oraz Petra, miasto będące dawniej stolicą Nabatejczyków wyrzeźbione w bajecznie kolorowych piaskowcach.

EN

The paper deals the expedition of students of the Faculty of Geology, Geophysics and Environmental Protection to Jordan, an Islamic Monarchy on the Arabian Peninsula. It borders upon Syria, Iraq, Saudi Arabia, Palestine and Israel. There are various touristic attractions connected with amazing history of the country, its culture and also geology. The main reason of this trip was to visit the most interesting geological sites considering geotourism. The route included the Dead Sea the lowest point on Earth, Wadi Rum Desert and Petra - the old Nabataean Arabs city carved in the marvelous sandstone.

11

Środowiska sedymentacji i rozwój depozycji osadów górnego czerwonego spągowca w rejonie Poznania

Aksamitowska A.

Przegląd Geologiczny

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2003

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Vol. 51, nr 2

168-174

PL

W obrębie osadów górnego czerwonego spągowca wydzielono kilkanaście litofacji oraz określono środowiska ich depozycji. Na podstawie przestrzennej analizy powiązanych ze sobą genetycznie litofacji opisano następstwo środowisk sedymentacyjnych w czasie i przestrzeni oraz czynników warunkujących ich rozwój. Było to podstawą do scharakteryzowania systemów depozycyjnych oraz opisu rozwoju sedymentacji górnego czerwonego spągowca na badanym obszarze. Rozpoznano dwa systemy depozycyjne: eoliczny i fluwialny. Ich rozwój i rozprzestrzenienie były kontrolowane przez procesy o charakterze tektonicznym oraz zmiany klimatyczne. Przeprowadzone badania pozwalają na dokładniejsze przeanalizowanie paleogeografii permskiej w trakcie sedymentacji osadów górnego czerwonego spągowca.

EN

Several lithofacies and their sedimentary environments were recognised within Upper Rotliegend deposits. Spatial analysis of genetically related lithofacies, allowed to descrite the sequence of sedimentary environments and factors controlling their evolution. It was the basis to characterise the depositional systems of the Upper Rotliegendes in the eastern Wielkopolska area. Two depositional systems were recognised: aeolian and fluvial. Their evolution was controlled by tectonic and climatic factors. This study permits a refinement ofpaleogeographic interpretation of the Upper Rotliegendes deposits.

12

Odkrywanie tajemnic pustyni

Linsenbarth A.

Geodeta : magazyn geoinformacyjny

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2000

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nr 12

82--86

13

Trudności budowania na terenach dolnej Mezopotamii przed tysiącami lat i współcześnie

Stańczyk A.

Drogownictwo

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2000

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nr 5

152-158

PL

Jest to świetny opis starożytnej i obecnej Mezopotamii z elementami podającymi problematykę budowy autostrady przez pustynię w Iraku przez "Dromex".