scholarly journals Study of the Corrosion Characteristics of Tunnel Fissures in a Karst Area in Southwest China

Geofluids ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-19 ◽  
Author(s):  
Yanjie Zhao ◽  
Fugang Wang ◽  
Cangsong Li ◽  
Yuqing Cao ◽  
Hailong Tian
Keyword(s):  
Field Experiments ◽  
Initial Permeability ◽  
Reaction Rate Constant ◽  
Practical Significance ◽  
Karst Area ◽  
Development Zone ◽  
Time Period ◽  
Fracture Development ◽  
Karst Areas ◽  
Soluble Rock

The development of the fissures in soluble rock of karst areas directly affects the construction and operation safety of tunnel engineering. It is thus of theoretical and practical significance to study the characteristics of its corrosion and its influencing factors. Taking the Wulong tunnel as the research object, the numerical model of the study area was established to quantitatively analyze the corrosion range, corrosion ratio, and changes in the permeability and porosity of the fissures in soluble rock of karst areas of the tunnel over the past 100 years, and the simulation results were verified by field experiments. The results show that the main controlling factor of the fissure corrosion of the tunnel in the karst area is the flow rate. The corrosion range and corrosion ratio of the fissures of the tunnels in the karst area increased with temperature because the reaction rate constant increased with temperature, causing the reactions’ equilibrium to move towards the direction of the solution. The larger the initial permeability and the larger the porosity of the fissures, the faster the fissures corrode. In the same time period, the fissures with high permeability and large porosity will lead to the permeability and porosity being more enhanced, thus causing the corrosion of the fissures to exhibit secondary enhancement effects. The opening of the dead-end pores greatly enhanced the permeability and slightly increased the porosity, which caused the differential corrosion of fissures in the karst area. The protection of the tunnel should be strengthened, mainly in strong hydrodynamic conditions and in the fracture development zone.

scholarly journals Influence of the growth regulator “Regoplant” and microfertilizer “Ultramag Kombi” on photosynthetic activity of potatoes in the forest-steppe zone Republic of North Ossetia-Alania

2021 ◽  
Vol 210 (07) ◽  
pp. 55-65
Author(s):  
Larisa Ikoeva ◽  
Oksana Haeva
Keyword(s):  
Growth Regulator ◽  
Field Experiments ◽  
Photosynthetic Activity ◽  
Low Cost ◽  
Weather Conditions ◽  
Steppe Zone ◽  
Practical Significance ◽  
Forest Steppe ◽  
Photosynthetic Productivity ◽  
North Ossetia

Abstract. The purpose of the work is to study the influence of the growth regulator “Regoplant” and microfertilizer “Ultramag Kombi” on the photosynthetic productivity of the potatoes of the Barna variety based on the results of field experiments in the forest-steppe zone Republic of North Ossetia-Alania. Methods. Studies on the tasks were carried out in 2018–2020. at the experimental site of the NCRIMFA branch of the VSC of RAS in the conditions of the forest-steppe zone Republic of North Ossetia-Alania according to generally accepted methods. The soil of the experimental plot is medium-power heavy loamy leached chernozem, lined with pebbles. Results. It is established, that biological products under identical soil and weather conditions assisted different progress of plants and approach of phases of vegetation. For all variants of the experiment, the number of stems increased by 0,3–0,7 pcs., the height of the stems of potato plants – by 3,8–4,9 cm in comparison with the control. An intense increase in the mass of tops occurred when using a tank mixture (growth regulator “Regoplant” (25 ml/ha) + microfertilizer “Ultramag Combi” (0,75 l/ha)) – by 74 g/bush, or 15.5 % compared with the control variant. During the growing season, the sum of the photosynthetic potential (FP) was 1,070 thousand m2 •days/ha in the control, and on average 1198–1406 thousand m2•days/ha in the experimental variants. The greatest accumulation of dry matter was noted when using a tank mixture – 917 g/m2. The maximum pure photosynthetic productivity was observed in experimental variant IV – 6,52 g/m2•day compared to the control option. Scientific novelty. For the first time in the forest-steppe zone Republic of North Ossetia-Alania the effect of the growth regulator “Regoplant” and microfertilizer “Ultramag Kombi” on photosynthetic activity of potatoes was studied. Practical significance. The studies carried out make it possible to recommend in potato production the use of a tank mixture of an effective growth regulator “Regoplant” at a dose of 25 ml/ha and microfertilizer “Ultramag Combi” at a dose of 0,75 l/ha, as an ecologically safe and low-cost agricultural method when processing vegetative plants, providing an increase in yield and quality of tubers.

scholarly journals Allosorex stenodus Fejfar, 1966 (Eulipotyphla, Soricidae): re-description of type material and re-interpretation of its fossil record

2020 ◽  
Vol 76 (1) ◽  
pp. 84-98
Author(s):  
Oldřich Fejfar ◽  
Wighart v. Koenigswald ◽  
Martin Sabol
Keyword(s):  
Fossil Record ◽  
Critical Evaluation ◽  
Morphological Characters ◽  
Microstructure Analysis ◽  
Karst Area ◽  
Eastern Asia ◽  
Enamel Microstructure ◽  
Fossil Remains ◽  
Karst Areas ◽  
Taxonomical Status

The original fossil record of Allosorex stenodus Fejfar, 1966 from Ivanovce (late Ruscinian, MN 15b) is redescribed and supplemented by the description of so far unpublished fossil remains, including upper dentition (P4 and M3) and a humerus fragment as well as the enamel microstructure analysis of m2. Based on the critical evaluation of other fossil remains from sites in Romania, Hungary, and France, the Ivanovce fossils are so far the only unquestionable recorded finds of A. stenodus in Europe, which can be considered as a local early Pliocene (MN 15) endemic species. Its occurrence is connected with the forested karst area along a broad valley of “pre-Váh” River, ecologically and climatically resembling the environment of modern karst areas in south-eastern Asia. Based on enamel microstructure analysis and unique mandible and dentition morphological characters, a separate taxonomical status of the species is also discussed.

scholarly journals Geochemical Implications of Rare Earth Elements in Terra Rossa in Tropical Karst Area: A Case Study in Northern Vietnam

2020 ◽  
Vol 10 (3) ◽  
pp. 858 ◽  
Author(s):  
Zhang Liankai ◽  
Ji Hongbing ◽  
Wang Shijie ◽  
Luo Gang ◽  
Liu Xiuming ◽  
...  
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Chemical Weathering ◽  
Karst Area ◽  
Oxidation Condition ◽  
Terra Rossa ◽  
Northern Vietnam ◽  
Material Sources ◽  
Karst Areas ◽  
Tropical Karst

Research on weathered crusts on carbonate rock is essential for paleoenvironmental studies in karst areas. Terra rossa, widely distributed in tropical karst areas, has not been studied in terms of its material sources and geochemistry. Two typical terra rossa profiles on dolomite (SC profile located at Sang Cai, Hoa Binh province) and limestone (TG profile located at Tong Gia, Lao Cai province) in Northern Vietnam were selected to examine the geochemical characteristics and the evolutionary processes of rare earth elements (REEs). Chondrite and bedrock normalized patterns indicated that these two profiles are in situ weathering crusts, meaning they are the residual material remaining after chemical weathering of the lower carbonate rocks. The average value of total REE in the SC profile is 381.19 ppm, which is 30 times higher than the bedrock. In the TG profile, the value is 386.26 ppm, 13 times higher than the bedrock. Compared with the profiles in nearby subtropical areas in Southeast China, the REE enrichment coefficients of terra rossa in Northern Vietnam are much higher. The REE depletion was also different between the SC and TG profiles. The light and heavy REE fractionations in the SC profile are higher than in the TG profile. Paleoclimate inversion analysis shows that the SC profile experienced a stable oxidation condition, whereas the TG profile was subjected to several reducing environments since a weathering crust formed.

Assessing specific agronomic responses of wheat cultivars in a winter rainfall environment

2011 ◽  
Vol 62 (2) ◽  
pp. 115 ◽  
Author(s):  
W. K. Anderson ◽  
A. J. van Burgel ◽  
D. L. Sharma ◽  
B. J. Shackley ◽  
C. M. Zaicou-Kunesch ◽  
...  
Keyword(s):  
Field Experiments ◽  
Practical Significance ◽  
Wheat Cultivars ◽  
Seeding Rate ◽  
Seed Rate ◽  
Site Analysis ◽  
Yield Level ◽  
Rate Interaction ◽  
A Site ◽  
N Rates

When new wheat cultivars are released for commercial production it is desirable to assist farmers to maximise the yield advantage by providing information about their responses to agronomic practices such as seeding rate and nitrogen (N) fertiliser. Over 3 years in 22 field experiments in the Mediterranean-type environment of Western Australia the response to seed rate and applied N fertiliser of current and recently released wheat cultivars was measured in factorial experiments under rain-fed conditions. A cross-site analysis showed that the environment × cultivar (location and year) or management (seed rate and N rate) interactions were relatively minor, explaining only 5% or less of the yield variation, in contrast to 89% accounted for by the environment. The analyses of individual experiments revealed that cultivars interacted more often with seeding rate (12 sites) than with applied N fertiliser rates (4 sites). Further, despite a frequent occurrence, the cultivar × seed rate interaction had only a marginal practical significance because the cultivar rankings at a site varied with season and the differences in optimum plant population were greater between sites and seasons than between cultivars at a site. The number of sites with positive and significant cultivar × N rate interaction was insufficient to generalise about the validity of the responses. The lack of any large differences between cultivars for their response to either seed rate or N rate implies the presence of a high inherent ability for compensation among yield components, thereby enabling the cultivars to exhibit an apparently high similarity for response to input levels. As such, it was not possible to generalise across environments in making clear suggestions for farmers to follow in respect of managing new cultivars differently from each other. It was concluded that despite the apparent desirability of providing information about differences between new and existing cultivars in their responses to seed and N rates at the time of release, they are more likely to be found where the differences between the cultivars are large, the testing sites are chosen so as to reduce the yield variance, and the yield level achieved in the experiments is above 2 t/ha.

scholarly journals Application of the APLIS Method for Groundwater Vulnerability Assessment in Rote Island Karst Areas

2021 ◽  
Vol 926 (1) ◽  
pp. 012071
Author(s):  
H Syafarini ◽  
H Hendrayana ◽  
S Winardi
Keyword(s):  
Soil Type ◽  
Land Surface ◽  
Groundwater Vulnerability ◽  
Karst Area ◽  
Gis Technique ◽  
West Part ◽  
Karst Areas ◽  
Groundwater Vulnerability Assessment ◽  
High Level ◽  
Aplis Method

Abstract The karst area on Rote Island dominates more than 60% of the Island. The land surface conditions in karst areas are generally dry, while below the subsurface is the potential for abundant water resources. This study aims to assess groundwater vulnerability using the APLIS (Altitude, Pendiete/Slope, Lithology, Infiltration, and Soils) method that will integrate with Geographic Information System (GIS) technique. The parameters used are elevation, slope, lithology, infiltration zone, and soil type. Slope and elevation are obtained from DEM maps, the soil is obtained from soil type maps, while lithology and infiltration zone are obtained from geological maps. The lithology and the infiltration zone in APLIS method analysis have a high role in determining the level of groundwater vulnerability. The groundwater vulnerability in Rote Island was divided into four classes: very low in the Northeast, low in the South, moderate in the East and North, and high in the East and West part of the Island. It explains that a high level of groundwater vulnerability in Rote Island needs to be used as a groundwater protection zone.

scholarly journals ANALISIS KONEKTIVITAS DAN KARAKTERISTIK LORONG PADA SISTEM HIDROGEOLOGI MATAAIR BETON, KAWASAN KARST GUNUNGSEWU, KABUPATEN GUNUNGKIDUL DENGAN UJI PERUNUTAN

2020 ◽  
Vol 12 (02) ◽  
pp. 105 ◽  
Author(s):  
Ahmad Cahyadi ◽  
Eko Haryono ◽  
Tjahyo Nugroho Adji ◽  
M Widyastuti ◽  
Muhammad Naufal ◽  
...  
Keyword(s):  
Catchment Area ◽  
Fluorescent Dyes ◽  
Groundwater Vulnerability ◽  
Tracer Test ◽  
Karst Area ◽  
Irrigated Rice ◽  
Karst Areas ◽  
Further Development ◽  
Hydrogeological System

Pemahaman tentang sistem hidrogeologi dan wilayah tangkapan air dari sebuah mata air sangatlah penting. Hal ini untuk membantu pengelolaan yang menjaga kelestariannya. Mataair Beton merupakan salah satu mataair yang memiliki peranan yang sangat penting di wilayah Ponjong, Kabupaten Gunungkidul. Suplai air dari mataair ini digunakan untuk memenuhi kebutuhan air bersih, irigasi persawahan dan perikanan. Penelitian ini bertujuan untuk mengetahui konektivitas dan karakterisasi lorong di sistem hidrogeologi Mataair Beton. Metode yang digunakan adalah tracer test dengan menggunakan fluorescent dyes. Hasil analisis menunjukkan bahwa Ponor Seropan memiliki konektivitas dengan Mataair Beton, dan memiliki karakteristik lorong berupa single conduit. Perkembangan lorong yang lanjut menunjukkan bahwa sistem hidrogeologi di lokasi kajian sangat dipengaruhi oleh imbuhan airtanah dari sistem alogenik yang berhulu di wilayah non-karst dan memiliki kerentanan terhadap pencemaran airtanah yang tinggi.Kata Kunci: Karst, Sungai Alogenik, Kawasan Karst Gunung Sewu, Uji Perunutan, Mataair BetonAn understanding of the hydrogeological system and catchment area of spring is very important. This is to help manage that maintains its sustainability. Beton Resurgence is one of the springs that have a very important role in the Ponjong area, Gunungkidul Regency. Water supply from the spring is used to supply clean water, irrigated rice fields, and fisheries. This study aims to determine the connectivity and characterization of Passage in the Beton hydrogeological system. The method used is a tracer test using fluorescent dyes. The results of the analysis of breaktrough curve indicate that Seropan Sinking Stream has connectivity with Beton resurgence, and has passage characteristics in the form of a single conduit. The further development of the passage shows that the hydrogeological system is strongly influenced by groundwater recharge originating from an allogenic system that originates in non-karst areas and has a high groundwater vulnerability to pollution. Keywords: Karst, Allogenic River, Gunungsewu Karst Area, Tracer Test, Beton Resurgence

scholarly journals EFFECT OF SURFACTANTS ON UPTAKE OF GIBBERELLIN A3 BY SOUR CHERRY LEAVES

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1167d-1167
Author(s):  
Moritz Knoche ◽  
Martin J. Bukovac
Keyword(s):  
Field Experiments ◽  
Biological Response ◽  
Sour Cherry ◽  
Flower Initiation ◽  
Abaxial Surface ◽  
Adaxial Surface ◽  
Response Data ◽  
Time Period ◽  
Order Of Magnitude ◽  
Spur Formation

Gibberellin A3 (GA) applied to virus-infected sour cherry (Prunus cerasus L., `Montmorency') trees inhibits flower initiation and promotes spur formation. However, response to a given dose may vary. Differential foliar absorption has been suggested as a major source of this variation. Therefore, we studied if surfactants would reduce variation in GA absorption. Uptake through the abaxial surface exceeded that through the adaxial surface by about one order of magnitude (adaxial surface 1.1 vs 7.8% in 1988, 0.7 vs 16.6% in 1989). GA uptake was markedly affected by surfactants. Over a 24-hr uptake period, Activator 90 and Ortho X-77 were most effective (abaxial surface 38.3 and 37.4% in 1989), whereas Regulaid did not affect GA uptake. L-77 significantly depressed absorption (abaxial surface 9.1% in 1989). In addition to the level of uptake, surfactants also changed GA absorption kinetics. Penetration increased linearly over a 96-hr time period when Regulaid was included. However, with Ortho X-77, uptake was rapid initially but levelled off within 96 hr. These findings will be discussed in relation to biological response data obtained in the field experiments.

scholarly journals STUDY ON KARST INFORMATION IDENTIFICATION OF QIANDONGNAN PREFECTURE BASED ON RS AND GIS TECHNOLOGY

2018 ◽  
Vol XLII-3 ◽  
pp. 2121-2125
Author(s):  
M. Yao ◽  
G. Zhou ◽  
W. Wang ◽  
Z. Wu ◽  
Y. Huang ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Karst Area ◽  
Karst Region ◽  
Karst Collapse ◽  
Distribution Map ◽  
Visual Interpretation ◽  
Remote Sensing Images ◽  
Karst Rocky Desertification ◽  
Rocky Desertification ◽  
Karst Areas

Karst area is a pure natural resource base, at the same time, due to the special geological environment; there are droughts and floods alternating with frequent karst collapse, rocky desertification and other resource and environment problems, which seriously restrict the sustainable economic and social development in karst areas. Therefore, this paper identifies and studies the karst, and clarifies the distribution of karst. Provide basic data for the rational development of resources in the karst region and the governance of desertification. Due to the uniqueness of the karst landscape, it can’t be directly recognized and extracted by computer in remote sensing images. Therefore, this paper uses the idea of “RS + DEM” to solve the above problems. this article is based on Landsat-5 TM imagery in 2010 and DEM data, proposes the methods to identify karst information research what is use of slope vector diagram, vegetation distribution map, distribution map of karst rocky desertification and other auxiliary data in combination with the signs for human-computer interaction interpretation, identification and extraction of peak forest, peaks cluster and isolated peaks, and further extraction of karst depression. Experiments show that this method achieves the “RS + DEM” mode through the reasonable combination of remote sensing images and DEM data. It not only effectively extracts karst areas covered with vegetation, but also quickly and accurately locks down the karst area and greatly improves the efficiency and precision of visual interpretation. The accurate interpretation rate of karst information in study area in this paper is 86.73 %.

scholarly journals Grafting Technique to Eliminate Rootstock Suckering of Grafted Tomatoes

HortScience ◽  
2011 ◽  
Vol 46 (4) ◽  
pp. 596-598 ◽  
Author(s):  
Michael G. Bausher
Keyword(s):  
Open Field ◽  
Field Experiments ◽  
First Year ◽  
Tomato Production ◽  
Grafting Technique ◽  
Time Period ◽  
Time Periods ◽  
The Difference ◽  
Fresh Tomato ◽  
Sprout Growth

Vegetative grafting has been proposed as a technique for managing diseases in tomatoes under open-field conditions. Over 2 successive years, we investigated the use of grafting under open-field fresh tomato production and found a serious limitation with current grafting techniques, which resulted in recurring rootstock shoot regrowth (“suckering”) from the rootstock cotyledons when left intact. Left unchecked, the regrowth of tomato rootstocks can envelop the experimental scions, which can impact the growth of field-grown tomatoes. In the Fall of 2007, the cultivars Multifort, Aloha, and TX-301 with ‘FL-47’ scions were grafted by a commercial propagator. These grafted plants were planted in a field experiment and after a time period, the number of rootstock suckers was counted and removed. This process was repeated over five time periods. In 2008, we grafted all of the plants below the rootstock cotyledons. During five different time periods spanning 57 d, bud regrowth from the rootstock occurred in all studied rootstocks in 2007. The difference in the 2 years was dramatic. In the first year, the number of plants with rootstock regrowth was as high as 84.6% in some of the plots for ‘Multifort’, 30.7% for ‘Aloha’, and 15.4% for ‘TX-301’. In the second year, with a different grafting technique, no regrowth from the rootstocks was observed. Even when the rootstock regrowth was removed in 2007, the rootstock sprout growth would reappear from the rootstock. The statistical interaction of the percentage of plants with rootstock regrowth for all recorded dates in 2007 was significant for ‘Multifort’ (Tukey-Fischer P ≤ 0.05) but not ‘Aloha’ or ‘TX-301’. Although the study also contained fumigation treatments, no interaction of soil treatments on root sprouting was observed. Since adopting this method, rootstock regrowth has not been observed in subsequent field experiments for the past 3 years.

scholarly journals Using Field Spectroradiometer to Estimate the Leaf N/P Ratio of Mixed Forest in a Karst Area of Southern China: A Combined Model to Overcome Overfitting

2021 ◽  
Vol 13 (17) ◽  
pp. 3368
Author(s):  
Wen He ◽  
Yanqiong Li ◽  
Jinye Wang ◽  
Yuefeng Yao ◽  
Ling Yu ◽  
...  
Keyword(s):  
Neural Network ◽  
Mean Squared Error ◽  
Southern China ◽  
Mixed Forest ◽  
General Regression Neural Network ◽  
Karst Area ◽  
Least Squares Regression ◽  
Fractional Differentiation ◽  
Karst Areas ◽  
Leaf N

The ratio between nitrogen and phosphorus (N/P) in plant leaves has been widely used to assess the availability of nutrients. However, it is challenging to rapidly and accurately estimate the leaf N/P ratio, especially for mixed forest. In this study, we collected 301 samples from nine typical karst areas in Guangxi Province during the growing season of 2018 to 2020. We then utilized five models (partial least squares regression (PLSR), backpropagation neural network (BPNN), general regression neural network (GRNN), PLSR+BPNN, and PLSR+GRNN) to estimate the leaf N/P ratio of plants based on these samples. We also applied the fractional differentiation to extract additional information from the original spectra of each sample. The results showed that the average leaf N/P ratio of plants was 17.97. Plant growth was primarily limited by phosphorus in these karst areas. The sensitive spectra to estimate leaf N/P ratio had wavelengths ranging from 400–730 nm. The prediction capabilities of these five models can be ranked in descending order as PLSR+GRNN, PLSR+BPNN, PLSR, GRNN, and BPNN when considering both accuracy and robustness. The PLSR+GRNN model yielded high R2 and performance to deviation (RPD), and low root mean squared error (RMSE) with values of 0.91, 3.15, and 1.98, respectively, for the training test and 0.81, 2.25, and 2.46, respectively, for validation test. Compared with the PLSR model, both PLSR+BPNN and PLSR+GRNN models had higher accuracy and were more stable. Moreover, both PLSR+BPNN and PLSR+GRNN models overcame the issue of overfitting, which occurs when a single model is used to predict leaf N/P ratio. Therefore, both PLSR+BPNN and PLSR+GRNN models can be used to predict the leaf N/P ratio of plants in karst areas. Fractional differentiation is a promising spectral preprocessing technique that can improve the accuracy of models. We conclude that the leaf N/P ratio of mixed forest can be effectively estimated using combined models based on field spectroradiometer data in karst areas.

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