Experimental Research of High Efficiency Water Reducing Agent in Improving Crack Resistance of Thin Layer Concrete

2014 ◽  
Vol 505-506 ◽  
pp. 188-191
Author(s):  
Ji Feng Liang ◽  
Chao Zhang ◽  
Yuan Hao Zhang
Keyword(s):  
Data Analysis ◽  
Carboxylic Acid ◽  
Thin Layer ◽  
Experimental Research ◽  
Crack Width ◽  
High Efficiency ◽  
Crack Depth ◽  
Measured Data ◽  
Maintenance Costs ◽  
Airport Pavement

After thin layer repaired, airport pavement will still appear crack, this situation not only spend a lot of maintenance costs, and seriously affect the use. This paper made flat constraint test for concrete containing poly carboxylic acid by using reinforced constraint plate mold, then the KON-FK(O) crack width tester and KON-FSY crack depth tester has been used in measuring on the surface of a block. Through the measured data analysis, crack effect is best when poly carboxylic acid with percentage of 2% and 2%.

THE EFFECTIVENESS OF USING COOPERATIVE SCRIPT METHOD TO IMPROVE STUDENTS’ READING COMPREHENSION ON RECOUNT TEXT OF 8th GRADE STUDENTS OF SMP N KEWAPANTE, MAUMERE IN ACADEMIC YEAR 2017/ 2018

2018 ◽  
Vol 2 (2) ◽  
pp. 210-220
Author(s):  
Wendelinus Oscar Janggo ◽  
Yuliana Wisnawati Nona Nungsi
Keyword(s):  
Reading Comprehension ◽  
Data Analysis ◽  
Experimental Research ◽  
Qualitative Data ◽  
Qualitative Data Analysis ◽  
Quantitative Data Analysis ◽  
8Th Grade ◽  
Eighth Grade Students ◽  
Quasi Experimental ◽  
Academic Year

This research is entitled “The Effectiveness of Using Cooperative Script Method to Improve Students’ Reading Comprehension on Recount Text of 8th Grade Students of SMP N Kewapante, Maumere in Academic Year 2017/ 2018”. The objective of this research is to investigate and to find out whether the use of cooperative script method effective to improve students’ reading comprehension on recount text. The method of this research is experimental research especially quasi experimental research. In analyzing the data, the researcher combined both quantitative and qualitative data analysis. In qualitative data analysis, the researcher used interview technique in order to get information about students’ perceptions in reading, while in quantitative data analysis, the researcher used SPSS version 16. The result of the research showed that the implementation of Cooperative Script Method in experimental class was more effective to help the students in reading comprehension on recount text compared to the use of the conventional method in control class of the eighth grade students of SMP N Kewapante, Maumere. It is also found that cooperative script method positively contributed to improve students’ reading comprehension. Therefore ,the researcher  suggests the teachers to use cooperative script method in order to improve students reading comprehension Additionally, cooperative script method can also motivate students to be more active, relax and enthusiastic to comprehend reading texts.

Chlorosulfonic Acid Supported Piperidine-4-carboxylic Acid (PPCA) Functionalized Fe3O4 Nanoparticles (Fe3O4-PPCA): The Efficient, Green and Reusable Nanocatalyst for the Synthesis of Pyrazolyl Coumarin Derivatives under Solvent-Free Conditions

2019 ◽  
Vol 22 (2) ◽  
pp. 123-128
Author(s):  
Setareh Habibzadeh ◽  
Hassan Ghasemnejad-Bosra ◽  
Mina Haghdadi ◽  
Soheila Heydari-Parastar
Keyword(s):  
Carboxylic Acid ◽  
Fe3o4 Nanoparticles ◽  
High Efficiency ◽  
Reaction Times ◽  
Chlorosulfonic Acid ◽  
Aromatic Aldehydes ◽  
Solvent Free ◽  
Magnetic Nanocatalyst ◽  
One Pot ◽  
Solvent Free Conditions

Background: In this study, we developed a convenient methodology for the synthesis of coumarin linked to pyrazolines and pyrano [2,3-h] coumarins linked to 3-(1,5-diphenyl-4,5- dihydro-1H-pyrazol-3-yl)-chromen-2-one derivatives using Chlorosulfonic acid supported Piperidine-4-carboxylic acid (PPCA) functionalized Fe3O4 nanoparticles (Fe3O4-PPCA) catalyst. Materials and Methods:: Fe3O4-PPCA was investigated as an efficient and magnetically recoverable Nanocatalyst for the one-pot synthesis of substituted coumarins from the reaction of coumarin with a variety of aromatic aldehydes in high to excellent yield at room temperature under solvent-free conditions. The magnetic nanocatalyst can be easily recovered by applying an external magnet device and reused for at least 10 reaction runs without considerable loss of reactivity. Results and Conclusion: The advantages of this protocol are the use of commercially available materials, simple and an inexpensive procedure, easy separation, and an eco-friendly procedure, and it shows good reaction times, good to high yields, inexpensive and practicability procedure, and high efficiency.

The Effect of Cracks on Chloride Penetration into Concrete

2007 ◽  
Vol 348-349 ◽  
pp. 769-772 ◽  
Author(s):  
In Seok Yoon ◽  
Erik Schlangen ◽  
Mario R. de Rooij ◽  
Klaas van Breugel
Keyword(s):  
Service Life ◽  
Crack Length ◽  
Significant Influence ◽  
Crack Width ◽  
Chloride Transport ◽  
Crack Depth ◽  
Chloride Penetration ◽  
Critical Crack ◽  
Chloride Migration ◽  
Migration Testing

This study is focused on examining the effect of critical crack width in combination with crack depth on chloride penetration into concrete. Because concrete structures have to meet a minimum service-life, critical crack width has become an important parameter. Specimens with different crack width / crack length have been subjected to rapid chloride migration testing (RCM). The results of this study show a critical crack width of about 0.012 mm. Cracks smaller than this critical crack width are considered not to have a significant influence on the rate of chloride transport inwards, while chloride penetration does proceed faster above this critical crack width.

Synthetic hydroxymethyl-porphyrins for protection of carboxy group

2007 ◽  
Vol 11 (06) ◽  
pp. 434-441 ◽  
Author(s):  
Hitoshi Tamiaki ◽  
Kouji Kumon ◽  
Reiko Shibata
Keyword(s):  
Liquid Phase ◽  
Carboxylic Acid ◽  
Thin Layer ◽  
Peptide Synthesis ◽  
Phenyl Group ◽  
Coupling Reagents ◽  
Protective Groups ◽  
Simple Filtration ◽  
Meso Position ◽  
Layer Chromatography

Hydroxymethyl-porphyrins were prepared by modifying tetraarylporphyrin possessing a p-(methoxycarbonyl)phenyl group at the meso-position and octaethylporphyrin. The synthetic alcohols reacted with carboxylic acids by the use of coupling reagents, to give the corresponding esters quantitatively. Due to the porphyrin dye moiety, the esterification was easily monitored on thin layer chromatography, and the resulting esters were highly soluble in most organic solvents and easily handled. The esters were readily cleaved by the action of an acid to give the original carboxylic acid and hydroxymethyl-porphyrin. Separation of the two species was performed by simple filtration: the carboxylic acid was soluble (filtrate) and the porphyrins were precipitates in methanol. These protective groups for carboxy groups were useful for peptide synthesis in the liquid phase.

scholarly journals Application of GGBFS and Bentonite to Auto-Healing Cracks of Cement Paste

2018 ◽  
Vol 1 (1) ◽  
pp. 38 ◽  
Author(s):  
J J Ekaputri ◽  
M S Anam ◽  
Y Luan ◽  
C Fujiyama ◽  
N Chijiwa ◽  
...  
Keyword(s):  
Cement Paste ◽  
Surface Crack ◽  
Crack Width ◽  
Healing Process ◽  
Crack Depth ◽  
The Self ◽  
External Loading ◽  
Self Healing ◽  
Carbonation Reaction ◽  
Granulated Blast Furnace Slag

Cracks are caused by many factors. Shrinkage and external loading are the most common reason. It becomes a problem when the ingression of aggressive and harmful substance penetrates to the concrete gap. This problem reduces the durability of the structures. It is well known that self – healing of cracks significantly improves the durability of the concrete structure. This paper presents self-healing cracks of cement paste containing bentonite associated with ground granulated blast furnace slag. The self-healing properties were evaluated with four parameters: crack width on the surface, crack depth, tensile strength recovery, and flexural recovery. In combination with microscopic observation, a healing process over time is also performed. The results show that bentonite improves the healing properties, in terms of surface crack width and crack depth. On the other hand, GGBFS could also improve the healing process, in terms of crack depth, direst tensile recovery, and flexural stiffness recovery. Carbonation reaction is believed as the main mechanism, which contributes the self-healing process as well as the continuous hydration progress.

scholarly journals Critical Stresses in Materials with Cracks

2019 ◽  
Vol 70 (7) ◽  
pp. 2442-2446
Author(s):  
Simona Eugenia Manea ◽  
Vali Ifigenia Nicolof ◽  
Teodor Sima
Keyword(s):  
Fracture Mechanics ◽  
Critical Stress ◽  
Crack Width ◽  
Crack Depth ◽  
Equivalent Stress ◽  
Critical Energy ◽  
Material Behavior ◽  
Experimental Results ◽  
Critical Stresses ◽  
Mechanics Concepts

The fracture mechanics concepts, as well as the concepts introduced on the basis of principle of critical energy, correlated with strength of materials with cracks is analysed. The equivalent stress method of strength was applied to cracked materials, by using the concept of local critical stress. This one depends on the material behavior and the deterioration due to crack. Experimental results have been obtained with specimens of OL304 steel with different cracks. The influence of crack depth and crack width is put into evidence.

A Fault-Tolerant Offset Algorithm for Measured Data with Defects

2014 ◽  
Vol 902 ◽  
pp. 344-350
Author(s):  
Xiang Jia Li ◽  
Ning Dai ◽  
Wen He Liao ◽  
Yu Chun Sun ◽  
Yong Bo Wang
Keyword(s):  
High Efficiency ◽  
Fault Tolerant ◽  
Engineering Application ◽  
Measured Data ◽  
Sphere Model ◽  
High Quality ◽  
Fitting Method ◽  
Enveloping Surface ◽  
Practical Engineering ◽  
Offset Surface

Offsetting of measured data, as a basic geometric operation, has already been widely used in many areas, like reverse engineering, rapid prototyping and NC machining. However, measured data always carry typical defects like caves and singular points. A fault-tolerant offset method is proposed to create the high quality offset surface of measured data with such defects. Firstly, we generated an expansion sphere model of measured data with the radius equivalent to the offset length. Secondly, using the computational geometry application of convex hull, we acquire the data of outermost enveloping surface of this expansion sphere model. Finally, we use local MLS projection fitting method to wipe out existing defects, and generate the high-quality triangular mesh surface of the offset model. The offset surface generated by this method is suitable for practical engineering application due to its high efficiency and accuracy.

Sign in / Sign up

Export Citation Format

Share Document