scholarly journals Evaluation of Collapse Sensitivity of Loess Soils and Its Effect on the Distribution Pattern of Pseudokarst Sinkholes at the Regional Scale (Case Study: Golestan Province, Northeastern Iran)

Author(s):  
Seddighe Zalaghaie ◽  
Mojtaba Heidari ◽  
Mohammad Reza Nikudel

Abstract The spread of loess soils in Golestan Province in northeastern Iran has caused considerable environmental issues. To evaluate the effect of loess collapse on the spatial distribution of pseudokarst sinkholes in this province, we have prepared undisturbed samples from 31 locations and characterized their physical and mechanical properties. Moreover, the collapse sensitivity in different parts of the study area has been determined by odometer tests under different pressures and calculation of three parameters, namely, the collapse coefficient (Ic), the time required for 90% settlement due to soil collapse (T90%), and initial collapse stress. Additionally, by conducting field surveying, using aerial photographs, satellite images, and drone flight, the coordinates of sinkholes were identified, and a map of their geographical distribution was prepared. The overlap of the sinkholes distribution map and the coefficient of collapse changes map showed that although the amount of Ic of sandy loess soils (Zone III) is higher than that of silty loess soils (Zone II), the extent of destructive phenomena such as sinkholes is much greater in Zone II than in Zone III. The overlap of the map of sinkholes distribution with the map of changes in collapse sensitivity (Is) of loess soils showed that the density of sinkholes in Zone II (which has higher collapse sensitivity) is higher than Zone III. In Zone II, due to severe collapse sensitivity, the highest concentration of sinkholes is observed in a unit area, more than 0.18 per square kilometer. With a relatively severe to severe collapse sensitivity in Zone III, this concentration is 0.021 per square kilometer. In Zone I (clayey loess), with slight-moderate collapse sensitivity, this destructive phenomenon is observed in the form of side instability since the study area is located in highlands. Furthermore, in this area, the sinkholes (0.004 per square kilometer) have the least concentration.

2015 ◽  
Vol 14 (11) ◽  
pp. 2591-2603 ◽  
Author(s):  
Maria Mortan ◽  
Patricia Ratiu ◽  
Vincentiu Veres ◽  
Leonina Baciu
Keyword(s):  

2021 ◽  
Vol 13 (14) ◽  
pp. 7909
Author(s):  
Robert V. Parsons

Controversy is common on environmental issues, with carbon taxation in Canada a current example. This paper uses Canada as a case study for analysis based around balanced presentation, a technique developed some time ago, yet largely forgotten. Using the method, analysis is shifted away from the point of controversy to a broader quantitative question, with comparative data employed from official government sources. Simple quantitative analysis is applied to evaluate emission trends of individual Canadian provinces, with quantitative metrics to identify and confirm the application of relevant emission reduction policies by individual jurisdictions. From 2005 through 2019, three provinces show consistent downward emission trends, two show consistent upward trends, and the remaining five have no trends, showing relatively “flat” profiles. The results clarify, in terms of diverse emission reduction policies, where successes have occurred, and where deficiencies or ambiguities have existed. Neither carbon taxation nor related cap-and-trade show any association with long-term reductions in overall emissions. One policy does stand out as being associated with long-term reductions, namely grid decarbonization. The results suggest a possible need within Canada to rethink emission reduction policies. The method may be relevant as a model for other countries to consider as well.


2021 ◽  
Vol 13 (15) ◽  
pp. 8351
Author(s):  
Brack W. Hale

The benefits from educational travel programs (ETPs) for students have been well-documented in the literature, particularly for programs looking at sustainability and environmental issues. However, the impacts the ETPs have on the destinations that host them have been less frequently considered; most of these studies focus, understandably, on destinations in the Global South. This paper draws on a framework of sustainable educational travel to examine how ETPs affect their host destinations in two case study destinations, based on the author’s professional experience in these locations, interviews with host organizations that use the lens of the pandemic, and information from government databases. The findings highlight an awareness of the sustainability of the destination, the importance of good, local partnerships with organizations well-connected in their communities, and educational activities that can benefit both students and hosts. Nonetheless, we have a long way to go to understand the full impacts of ETPs on their host destinations and thus truly learn to avoid them.


2021 ◽  
Vol 13 (8) ◽  
pp. 4487
Author(s):  
Maghsoud Amiri ◽  
Mohammad Hashemi-Tabatabaei ◽  
Mohammad Ghahremanloo ◽  
Mehdi Keshavarz-Ghorabaee ◽  
Edmundas Kazimieras Zavadskas ◽  
...  

Evaluating the life cycle of buildings is a valuable tool for assessing sustainability and analyzing environmental consequences throughout the construction operations of buildings. In this study, in order to determine the importance of building life cycle evaluation indicators, a new combination method was used based on a quantitative-qualitative method (QQM) and a simplified best-worst method (SBWM). The SBWM method was used because it simplifies BWM calculations and does not require solving complex mathematical models. Reducing the time required to perform calculations and eliminating the need for complicated computer software are among the advantages of the proposed method. The QQM method has also been used due to its ability to evaluate quantitative and qualitative criteria simultaneously. The feasibility and applicability of the SBWM were examined using three numerical examples and a case study, and the results were evaluated. The results of the case study showed that the criteria of the estimated cost, comfort level, and basic floor area were, in order, the most important criteria among the others. The results of the numerical examples and the case study showed that the proposed method had a lower total deviation (TD) compared to the basic BWM. Sensitivity analysis results also confirmed that the proposed approach has a high degree of robustness for ranking and weighting criteria.


2021 ◽  
Vol 281 ◽  
pp. 116977
Author(s):  
Shushen Yang ◽  
Wenzhao Feng ◽  
Shiqin Wang ◽  
Liang Chen ◽  
Xin Zheng ◽  
...  

2021 ◽  
Vol 13 (7) ◽  
pp. 3705
Author(s):  
Veterina Nosadila Riaventin ◽  
Sofyan Dwi Cahyo ◽  
Ivan Kristianto Singgih

This study discusses the problem of determining which container port should be developed within an existing network and when this should be carried out. A case study of Indonesia’s port network is presented, where several new ports are to be improved to ensure smooth interisland transportation flows of goods. The effects of the investment on economic consequences and increased network connectivity are assessed. When improving the ports, we consider that the available budget limits the investment. The network connectivity is evaluated by considering the number of reachable ports from the developed ports or transportation time required from other ports within the same port cluster. Based on our knowledge, our study is the first one that discusses the investment problem in multiple container ports under single management, as well as its effects regarding the increase in container flows. The problem is introduced and three mathematical models are proposed and used to solve a real problem. The results show that different models have different improved aspects of container transportation flows—e.g., a balanced improvement of the whole port network (Model 2) and appropriate investment priority for port clusters (Model 3).


Geosciences ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 330
Author(s):  
Bryan A. Oakley

Napatree Point, an isolated barrier in southern Rhode Island, provides a case study of barrier spit migration via storm driven overwash and washover fan migration. Documented shoreline changes using historical surveys and vertical aerial photographs show that the barrier had little in the way of net change in position between 1883 and 1939, including the impact of the 1938 hurricane. The barrier retreated rapidly between 1945 and 1975, driven by both tropical and extra-tropical storms. The shoreline position has been largely static since 1975. The removal of the foredune during the 1938 hurricane facilitated landward shoreline migration in subsequent lower intensity storms. Dune recovery following the 1962 Ash Wednesday storm has been allowed due to limited overwash and barrier migration over the last several decades. Shoreline change rates during the period from 1945–1975 were more than double the rate of shoreline change between 1939 and 2014 and triple the rate between 1883 and 2014, exceeding the positional uncertainty of these shoreline pairs. The long-term shoreline change rates used to calculate coastal setbacks in Rhode Island likely underestimate the potential for rapid shoreline retreat over shorter time periods, particularly in a cluster of storm activity. While sea-level rise has increased since 1975, the barrier has not migrated, highlighting the importance of storms in barrier migration.


2012 ◽  
Vol 195 ◽  
pp. 128-131 ◽  
Author(s):  
Hun Hee Lee ◽  
Min Sang Yun ◽  
Hyun Wook Lee ◽  
Jin Goo Park

As the feature size of semiconductor device shrinks continuously, various high-K metals for 3-D structures have been applied to improve the device performance, such as high speed and low power consumption. Metal gate fabrication requires the removal of metal and polymer residues after etching process without causing any undesired etching and corrosion of metals. The conventional sulfuric-peroxide mixture (SPM) has many disadvantages like the corrosion of metals, environmental issues etc., DSP+(dilute sulfuric-peroxide-HF mixture) chemical is currently used for the removal of post etch residues on device surface, to replace the conventional SPM cleaning [. Due to the increased usage of metal gate in devices in recent times, the application of DSP+chemicals for cleaning processes also increases [.


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