scholarly journals Microscopic Mechanism of Cement Improving the Strength of Lime-Fly Ash-Stabilized Yellow River Alluvial Silt

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Xiaobin Zhang ◽  
Zhiduo Zhu
Keyword(s):  
Fly Ash ◽  
Yellow River ◽  
Early Stage ◽  
Soil Samples ◽  
Microscopic Mechanism ◽  
Dense Particle ◽  
Microstructure Characteristics ◽  
Particle Arrangement ◽  
Before And After ◽  
Early Strength

Silt is a kind of soil with poor engineering performance. Lime-fly ash- (LF-) stabilized silt has the problem of low early strength. In this study, it is aimed to investigate the effect of cement on improving the strength of LF-stabilized silt and reveal the microscopic mechanism. A fixed percentage of LF (18%) plus different percentages of cement (0%, 2%, 4%, and 6%) were mixed with Yellow River alluvial silt (YRAS). Soil samples for tests were artificially made by compaction in the laboratory. Unconfined compressive strength (UCS) tests were performed on soil samples cured for 7 d, 28 d, 60 d, and 90 d. Scanning electron microscope (SEM) tests, energy dispersive X-ray spectroscopy (EDS) tests, and mercury intrusion porosimetry (MIP) tests were performed on soil samples cured for 7 d and 28 d. UCS results showed that the early strength of LF-stabilized YRAS developed significantly after adding cement. UCS also increased with the increase in cement content and curing time. SEM results revealed the differences in microstructure of LF-stabilized YRAS before and after adding cement. Before adding cement, the main microstructure characteristics included small soil particles, large number of pores, and loose particle arrangement. After adding cement, the main microstructure characteristics included large bonded particles, small number of pores, and dense particle arrangement. The EDS results showed that, after curing for 28 d, the elements of gels in stabilized YRAS had changed, mainly including appearance of C and a significant increase of Ca. MIP results showed that the pores with a size of 1 μm∼10 μm accounted for the largest proportion in stabilized YRAS. The product (mainly C-S-H) of cement hydration mainly filled the pores with a size larger than 10 μm at the early stage. Combining strength results and microresults, the micromechanism of cement improving the strength of LF-stabilized YRAS was discussed.

Microscopic Mechanism of the Diffusivity of Concrete Chloride Ion

2013 ◽  
Vol 773 ◽  
pp. 687-692 ◽  
Author(s):  
Jun Liu ◽  
Feng Xing ◽  
Bi Qing Dong
Keyword(s):  
Fly Ash ◽  
Early Stage ◽  
Great Influence ◽  
Chloride Ion ◽  
Test Method ◽  
Mineral Admixture ◽  
Microscopic Mechanism ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
The Impact

Use concrete specimens with different mix proportions to conserve them for 90d taking into account the influence of mineral admixture material---fly ash. Then adopts the RCM test method to measure the rapid diffusivity of chloride ion of concrete and observes the microstructure of the cement paste using the SEM (scanning electron microscopy), aiming to study the impact of fly ash on its hydration process. The results show that the micro-pore structure of the concrete has a great influence on the rapid diffusivity of chloride ion, while its diffusivity is closely related with the water-cement ratio of concrete; after the fly ash is added, the ettringite generation of the concrete in the early stage decreases, and the interspace of the transition zone between the hydrated particles and hydration slurry is enlarged, coupled with the increase in the intercommunicating pore; after curing for 90d, the chloride ion diffusivity decreases significantly with the increase in the dosage of fly ash. For the concrete with the fly ash dosage of 15%, its chloride ion diffusivity is only 75.4% of that with the same water-cement ratio; when its fly ash content is 30%, its chloride ion diffusivity is only 32.3% of the ordinary concrete.

Evaluation of Metal Contents in Correlation with Phytosanitary Treatments at Vineyard

2017 ◽  
Vol 68 (6) ◽  
pp. 1289-1293
Author(s):  
Oana Mihai ◽  
Octav Pantea ◽  
Daniela Roxana Popovici ◽  
Catalina Gabriela Gheorghe
Keyword(s):  
Soil Samples ◽  
Flame Atomic Absorption ◽  
Mobile Forms ◽  
Before And After ◽  
Phytosanitary Treatment ◽  
Zinc Concentrations ◽  
Zinc Levels ◽  
Ph Range ◽  
In The Beginning ◽  
Short Time

The present work aims with the evaluation of copper, manganese and zinc concentrations (mobile forms) from vineyard soil before and after phytosanitary treatment with Curzate Manox and Dithane M-45 compounds, during and after remanence period. Different vineyard soils types were collected at 0-20 cm and 20-40 cm depths. Flame Atomic Absorption Spectroscopy (FAAS) method was used for measurements of the micronutrients. The soil samples were analyzed after 5 and 21 days after treatment application. Since copper is mainly accumulates in the upper layer following fungicidal sprays application, high levels of copper concentrations are obtained. The soil samples exhibits different behavior in terms of manganese and zinc contents. Manganese and zinc levels are classified as medium in the beginning of the experiment (Mn-M0 and Zn-M0), whereas these levels increased in the soil samples (at moments M1- 5 days and M2- 21 days after treatment). This behavior can be due to the Mancozeb decomposition, knowing that Mancozeb decomposes in the pH range 5-9 and it remains short time into the soil.

Influence of Applied Phytosanitary Treatments and Climatic Crop Year on Zinc Content in Wines from Tohani Vineyard

2017 ◽  
Vol 68 (9) ◽  
pp. 2092-2097
Author(s):  
Catalina Calin ◽  
Gina Vasile Scaeteanu ◽  
Roxana Maria Madjar ◽  
Otilia Cangea
Keyword(s):  
Zinc Content ◽  
Soil Samples ◽  
Limit Set ◽  
Red Wines ◽  
Metallic Ions ◽  
Sauvignon Blanc ◽  
Before And After ◽  
Haze Formation ◽  
Zinc Levels ◽  
Concentration Levels

Metallic ions present a great importance in oenological practice and usually are present in wines in levels that are not hazardous. Among all metallic ions, zinc presents a great interest because may cause the persistence of the wine sour taste and by the side of Al, Cu, Fe and Ni, contribute to the haze formation and the change of color. The present study was focused on measuring the concentration levels of mobile zinc from vineyard soil before and after phytosanitary treatments and zinc content from white (Feteasca Alba - FA, Riesling Italian - RI, Sauvignon Blanc - SB, Tamaioasa Rom�neasca - TR), rose (Busuioaca de Bohotin - BB) and red (Feteasca Neagra - FN) wines within the wine-growing Tohani area, Romania. Other objective was to investigate of the influence of crop year and variety on zinc levels found in wine samples. Mobile zinc content for all analyzed soil samples is low ([1.5 mg/kg). Analyses indicated that zinc content found in wines was below 5 mg/L, limit set by Organisation Internationale of Vine and Wine (OIV). Also, it was found that red wines contain zinc in higher concentrations than white ones.

A Comparative Study of Amalaki Choorna along with Madhu and Vata Twak Kashaya Yoni Pichu Dharana in the Management of Shweta Pradara

2017 ◽  
Vol 2 (4) ◽  
Author(s):  
Renuka M. Tenahalli
Keyword(s):  
Vitamin C ◽  
Early Stage ◽  
Pathological Condition ◽  
Before And After ◽  
Group A ◽  
Phosphorus Iron ◽  
Group B ◽  
Busy Schedule ◽  
Iron And Calcium

Shweta Pradara (Leucorrhoea) is the disease which is characterized by vaginal white discharge. Vaginal white discharge this symptom is present in both physiological and pathological condition, when it becomes pathological it disturbs routine life style of the woman. Most of the women in the early stage will not express the symptoms because of hesitation and their busy schedule. If it is not treated it may leads to chronic diseases like PID (Garbhashaya Shotha etc.) Charaka mentioned Amalaki Choorna along with Madhu and Vata Twak Kashaya Yoni Pichu Dharana. This treatment is used in Shweta Pradara shown positive results, hence a study was under taken to assess its clinical efficacy. 30 diagnosed patients of Shweta Pradara were randomly selected, allocated in three groups. Group A and Group B received Amalaki Choorna with Madhu and Vata Twak Kashaya Yoni Pichu Dharana respectively and Group C received Amalaki Choorna with Madhu followed by Vata Twak Kashaya Yoni Pichu Dharana for 15 days. The patients were assessed for the severity of the symptoms subjectively and objectively before and after the treatment and at the end of the follow up. Data from each group were statistically analyzed and were compared. No side effects were noted and it may be considered as an effective alternative medicine in Shweta Pradara (leucorrhea). Amalaki is rich in natural source of vitamin C and contains phosphorus, iron and calcium. Honey contains carbohydrate, vitamin C, phosphorus iron and calcium. All together these help to increase Hb% and immunity. Vata Twak Kashaya contains tannin which helps to maintain normal pH of the vagina.

scholarly journals The Influence of Drying-Wetting Cycles on the Suction Stress of Compacted Loess and the Associated Microscopic Mechanism

Water ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 1809
Author(s):  
Yongpeng Nie ◽  
Wankui Ni ◽  
Xiangning Li ◽  
Haiman Wang ◽  
Kangze Yuan ◽  
...  
Keyword(s):  
Filter Paper ◽  
Pore Diameter ◽  
Matric Suction ◽  
Microscopic Mechanism ◽  
Suction Stress ◽  
Dominant Soil ◽  
Before And After ◽  
Soil Pores ◽  
Paper Method ◽  
Compacted Loess

To better understand and analyze the unsaturated stability of loess filling body, it is necessary to study the changes in suction stress before and after the drying-wetting cycles. In this study, the SWCC of compacted loess before and after drying-wetting cycles was tested using the filter paper method. Then, the suction stress was calculated and the microstructure of the loess sample was determined by the SEM and NMR. The results showed that the drying-wetting cycles had an important influence on the SSCC and microstructure of compacted loess. The change in suction stress before and after the drying-wetting cycles can be well explained by the loess microstructure. The drying-wetting cycles did not significantly change the basic trend of the compacted loess’s SSCC, but it increased the porosity and the dominant pore diameter of loess, and reduced the suction stress under the same matric suction. The main significant change in suction stress with matric suction occurred within the range of the dominant soil pores. The larger the dominant pore diameter, the smaller the suction stress under the same matric suction. In addition, this study proposes a new method for calculating suction stress based on the PSD parameters.

scholarly journals Assessment of Characteristics of Acid Mine Drainage Treated with Fly Ash

2021 ◽  
Vol 11 (9) ◽  
pp. 3910
Author(s):  
Saba Shirin ◽  
Aarif Jamal ◽  
Christina Emmanouil ◽  
Akhilesh Kumar Yadav
Keyword(s):  
Fly Ash ◽  
Acid Mine Drainage ◽  
Power Plants ◽  
Mine Drainage ◽  
Thermal Power ◽  
Mineralogical Characterization ◽  
Acid Mine ◽  
Before And After ◽  
Abandoned Coal Mines

Acid mine drainage (AMD) occurs naturally in abandoned coal mines, and it contains hazardous toxic elements in varying concentrations. In the present research, AMD samples collected from an abandoned mine were treated with fly ash samples from four thermal power plants in Singrauli Coalfield in the proximate area, at optimized concentrations. The AMD samples were analyzed for physicochemical parameters and metal content before and after fly ash treatment. Morphological, geochemical and mineralogical characterization of the fly ash was performed using SEM, XRF and XRD. This laboratory-scale investigation indicated that fly ash had appreciable neutralization potential, increasing AMD pH and decreasing elemental and sulfate concentrations. Therefore, fly ash may be effectively used for AMD neutralization, and its suitability for the management of coalfield AMD pits should be assessed further.

Experimental Study on Mechanical Property of Concrete Based on Seawater and Sea Sand

2013 ◽  
Vol 641-642 ◽  
pp. 574-577 ◽  
Author(s):  
Ying Tao Li ◽  
Ling Zhou ◽  
Mao Jiang ◽  
Yu Zhang ◽  
Jun Shao
Keyword(s):  
Mechanical Property ◽  
Experimental Study ◽  
Fly Ash ◽  
Raw Materials ◽  
Growth Trend ◽  
Sea Sand ◽  
Significant Strength ◽  
Dry Conditions ◽  
Early Strength ◽  
Better Than

In this paper, the mechanical property experiments of concrete based on the seawater and sea sand have been carried in different raw materials preparation and different conservation environments. The results show that the early strength and late strength of concrete based on seawater and sea sand are better than concrete based on freshwater and sand. There is no significant strength decreased for concrete based on seawater and sea sand under accelerated alternating wet and dry conditions. For concrete based on seawater and sea sand mixed with admixture, the downward trend of late strength is significantly delayed, the late strength of concrete based on the seawater and sea sand mixed with slag gets the most obvious growth trend, while the late strength of seawater and sea sand concrete mixed with fly ash gets the largest increment.

Early strength behaviour of fly ash concretes

1994 ◽  
Vol 24 (2) ◽  
pp. 277-284 ◽  
Author(s):  
K. Ganesh Babu ◽  
G. Siva Nageswara Rao
Keyword(s):  
Fly Ash ◽  
Early Strength

scholarly journals Rearing Drones in Queen Cells of Apis mellifera Honey Bees

2016 ◽  
Vol 60 (2) ◽  
pp. 119-128
Author(s):  
Georgios Goras ◽  
Chrysoula Tananaki ◽  
Sofia Gounari ◽  
Elissavet Lazaridou ◽  
Dimitrios Kanelis ◽  
...  
Keyword(s):  
Apis Mellifera ◽  
Larval Development ◽  
Honey Bees ◽  
Royal Jelly ◽  
Early Stage ◽  
Egg Laying ◽  
Horizontal Position ◽  
Before And After ◽  
Queen Larvae ◽  
As If

Abstract We investigated the rearing of drone larvae grafted in queen cells. From the 1200 drone larvae that were grafted during spring and autumn, 875 were accepted (72.9%) and reared as queens. Drone larvae in false queen cells received royal jelly of the same composition and of the same amounts as queen larvae. Workers capped the queen cells as if they were drones, 9-10 days after the egg laying. Out of 60 accepted false queen cells, 21 (35%) were capped. The shape of false queen cells with drone larvae is unusually long with a characteristically elongate tip which is probably due to the falling of larvae. Bees start the destruction of the cells when the larvae were 3 days old and maximised it before and after capping. Protecting false queen cells in the colony by wrapping, reversing them upside down, or placing in a horizontal position, did not help. The only adult drones that emerged from the false queen cells were those protected in an incubator and in push-in cages. Adult drones from false queen cells had smaller wings, legs, and proboscis than regular drones. The results of this study verify previous reports that the bees do not recognise the different sex of the larvae at least at the early stage of larval development. The late destruction of false queen cells, the similarity in quality and quantity of the produced royal jelly, and the bigger drone cells, allow for the use of drone larvae in cups for the production of royal jelly.

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