scholarly journals Effectiveness of geogrids in roadway construction by large scale laboratory tests

2020 ◽  
Author(s):  
Guangfan Zheng
1992 ◽  
Vol 34 (3) ◽  
pp. 183-191 ◽  
Author(s):  
Virginia Torres Schall ◽  
Mauricio Carvalho de Vasconcellos ◽  
Ana Luiza Villaça-Coelho ◽  
Fátima Eliana Ferreira-Lopes ◽  
Ivonise Paz da Silva

Laboratory tests with aqueous solutions of Euphorbia splendens var. hislopii latex have demonstrated seasonal stability of the molluscicidal principle, with LD90 values of 1.14 ppm (spring), 1.02 ppm (fall), 1.09 ppm (winter), and 1.07 ppm (summer) that have been determined against Biomphalaria tenagophila in the field. Assays on latex collected in Belo Horizonte and Recife yielded LD90 values similar to those obtained with the reference substance collected in Rio de Janeiro (Ilha do Governador), demonstrating geographic stability of the molluscicidal effect. The molluscicidal action of aqueous dilutions of the latex in natura, centrifuged (precipitate) and lyophilized, was stable for up to 124 days at room temperature (in natura) and for up to 736 days in a common refrigerator at 10 to 12ºC (lyophilized product). A 5.0 ppm solution is 100% lethal for snails up to 13 days after preparation, the effect being gradually lost to almost total inactivity by the 30th day. This observation indicated that the active principle is instable. These properties together with the wide distribution of the plant, its resistance and adaptation to the tropical climate, its easy cultivation and the easy obtention of latex and preparation of the molluscicidal solution, make this a promising material for large-scale use in the control of schistosomiasis


Author(s):  
M. F. Overton ◽  
J. S. Fisher ◽  
A. L. Stone

1978 ◽  
Vol 41 (9) ◽  
pp. 684-688 ◽  
Author(s):  
S. GORDIN ◽  
I. ROSENTHAL

Comparative laboratory tests of cheesemaking show similarity between chicken pepsin and calf rennet. Suitability of chicken pepsin for large-scale production of Emmental (Swiss) and Kashkaval-type cheeses was tested.


Author(s):  
Lisham Bonakdar ◽  
Hocine Oumeraci

Wave loads on a slender pile within a group of piles are studied by means of (i) large-scale laboratory tests carried out in the Large Wave Flume (GWK) of the Coastal Research Centre (FZK) in Hannover, and (ii) small scale experiments performed in 2 m-wide wave flume of Leichtweiss-Institute for Hydraulic Engineering and Water Resources (LWI), in Braunschweig, Germany. The small scale model tests (LWI) were scaled down (1:6.5) by Froude law from the large scale model tests (GWK). Scale and model effects are examined by comparing the results of small and large scale laboratory tests.


2021 ◽  
Vol 13 (12) ◽  
pp. 6919
Author(s):  
Izabela-Maria Apostu ◽  
Maria Lazar ◽  
Florin Faur

Some valuable minerals, such as lignite, are extracted through open-pit mining works. After the cessation of mining activity, large-scale gaps result in the landscape. These gaps, also called “remaining gaps”, represent some of the roughest types of environmental impacts. After the cessation of mining activity, recovery and ecological restoration works are required. However, it is first necessary to carry out risk assessment studies considering the possible future influences on the final slopes. For this study, flooding of the remaining lignite open-pits gaps was considered as the ecological restoration option. The study was based on extensive research, including sampling, laboratory tests, statistical-mathematical processing, hypothesis formulation, evaluations, interpretations, and field observations, regarding the rock behavior and occurrence of negative geotechnical phenomena (geotechnical phenomena that have a negative impact and a risk on the integrity of the environment and local communities, such as landslides, rockfalls, liquefaction, suffosis) during the flooding process. This paper’s originality consists of combining the methods and methodologies developed with the help of classic methods (Fellenius, Janbu, and Bishop methods) and probabilistic ones (Rosenblueth method) existing in the specialized literature for solving the proposed problem and structuring the information similar to a guide.


2019 ◽  
Vol 19 (1) ◽  
pp. 181-199 ◽  
Author(s):  
Yung Ming Cheng ◽  
Wing Hong Ivan Fung ◽  
Liang Li ◽  
Na Li

Abstract. Natural as well as fill slopes are commonly found in Hong Kong, China, and many other countries, and slope failures with the subsequent debris flows have caused a serious loss of life and property in the past until now. There are various processes and features associated with debris flow which engineers need to know so as to design for the precautionary measures. In this study, experiments on flume tests, friction tests, deposition tests, and rebound tests were carried out for different sizes of balls to determine the parameters required for the modelling of dry granular flow. Different materials and sizes of balls are used in the flume tests, and various flow pattern and segregation phenomena are noticed in the tests. Distinct element modelling (DEM) of dry granular flow is also carried out for the flow process. It is found that for simple cases, the flow process can be modelled reasonably well by DEM, which is crucial for engineers to determine the pattern and impact of granular flow, which will lead to further study in more complicated debris flow. From laboratory tests, large-scale field tests, and numerical simulations of single- and multiple-material tests, it is also found that the particle size will be the most critical factor in the segregation process during granular flow. It is also found from the laboratory tests and numerical simulations that a jump in the flume can help to reduce the final velocity of the granular flow, which is useful for practical purposes.


2020 ◽  
Author(s):  
A. L. Martins ◽  
H. F .L. Santos ◽  
B. B. Castro ◽  
A. S. Gonçalves ◽  
D. A. Maffra ◽  
...  

1969 ◽  
Vol 59 (1) ◽  
pp. 113-117 ◽  
Author(s):  
Hafiz Ahmed

Experiments were carried out to remove existing doubts about the toxicity (and therefore cost per unit killing power) of malathion to adults of Schistocerca gregaria (Forsk.) which have arisen from earlier field and laboratory tests. Malathion is shown to be almost as toxic to these insects as γ-BHC, but superior in speed of action. These observations are in agreement with the performance of these two compounds in the field.Subdivision of a dose of malathion with simultaneous application at two loci increased its toxicity. This, as well as other factors, brings the value of LD50 determinations into question. Recommendations for large-scale use of new insectsicides, based only on laboratory data, may not always be reliable.


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