Carbon Fiber Reinforced Cement and Mortar

1990 ◽  
Vol 211 ◽  
Author(s):  
J. R. Linton ◽  
P. L. Berneburg ◽  
E. M. Gartner ◽  
A. Bentur
Keyword(s):  
Carbon Fibers ◽  
Fiber Length ◽  
Length Distribution ◽  
Fiber Breakage ◽  
Image Analysis Technique ◽  
Analysis Technique ◽  
Reinforcing Fibers ◽  
Before And After ◽  
Reinforced Cement ◽  
Critical Fiber Length

AbstractAlthough carbon fibers have high tensile strengths and are chemically inert, their application in cementitious composites is limited due to their brittleness. An image analysis technique employed to determine the length distribution of the reinforcing fibers before and after mixing in cement paste and mortar matrices indicates that substantial fiber breakage occurs during mixing. In paste mixtures, the average fiber length after mixing remains above the critical fiber length, but in mortar mixes the average fiber length falls below the critical fiber length resulting in no significant enhancement of composite flexural properties.

Nature of Fiber Loss in Combing

1971 ◽  
Vol 41 (8) ◽  
pp. 697-700 ◽  
Author(s):  
R. G. Owalekar
Keyword(s):  
Fiber Length ◽  
Length Distribution ◽  
Fiber Breakage ◽  
General Increase ◽  
Fiber Length Distribution ◽  
Drawing Frame ◽  
Long Fibers

Fiber-length distribution of comber sliver was compared with that of the comber lap to find out the amount of fiber loss obtained in various length groups. Such an analysis of the fiber loss was found to be useful in understanding the mechanism of fiber removal and fiber breakage in combing. Effect of important factors, such as step gauge, top comb action, and lap preparation, was studied. Distribution of fiber loss vs fiber length was found to be bimodal with Drawing-Super lap preparation. This was due to the fact that the actual probability of fiber removal decreases while that of fiber breakage increases with increased fiber length. As the pieces of broken long fibers contribute to the middle-length groups, the fiber loss was found to be minimum in this group. Use of wider step gauges, use of top comb, and presence of prominent trailing hooks were found to give a general increase in the fiber loss in all length groups. Long staple cottons were found to give relatively more fiber breakage, while use of extra drawing frame in the lap preparation was found to give much less fiber breakage.

An effective model for fiber breakage prediction of injection-molded long fiber reinforced thermoplastics

2020 ◽  
Vol 39 (11-12) ◽  
pp. 473-484 ◽  
Author(s):  
Junyang Kang ◽  
Ming Huang ◽  
Mengfei Zhang ◽  
Na Zhang ◽  
Gang Song ◽  
...  
Keyword(s):  
Shear Stress ◽  
Fiber Length ◽  
Length Distribution ◽  
Effective Model ◽  
Fiber Breakage ◽  
Fiber Reinforced ◽  
Fiber Length Distribution ◽  
Glass Fiber Reinforced ◽  
Strong Shear ◽  
Reinforced Thermoplastics

Fiber length is an important factor affecting the mechanical properties of long fiber reinforced thermoplastic (LFRT). When LFRT is processed by injection molding, the strong shear flow usually leads to severe fiber breakage. Therefore, it is a crucial issue to reduce the loss of fiber length as much as possible during composite molding. Current work focused on constructing an effective model for predicting fiber breaking caused by shear stress during melt filling. Based on the Oseen formula, the disturbance of liquid flow caused by a single external force was studied, and the force acceptance formula of fiber immersed in flow field was derived. A mechanical model for characterizing the degree of fibers buckling and breaking and the shear stress was constructed by the Euler buckling criterion. To verify the model, glass fiber reinforced polypropylene (GF/PP) composites with initial fiber length of 3 mm and 6 mm was subjected to shear at the specific shear rate by using a rotating rheometer. The length of GF after sheared was measured by fiber length distribution analyser. The breaking ratio of fibers was predicted using the new model, and the predicted results were in good agreement with experiment, although more comparisons with experiments are necessary.

Effects of Level of Fiber Opening on Moisture Regain, Tenacity, and Breakage of Wool

1997 ◽  
Vol 67 (1) ◽  
pp. 50-56
Author(s):  
A. Suadipradja ◽  
X. Wang
Keyword(s):  
Fiber Bundle ◽  
Fiber Length ◽  
Fiber Breakage ◽  
Moisture Regain ◽  
Before And After ◽  
Opening Process

We have studied the effects of the level of fiber opening, expressed in points per fiber (ppf), on the reduction in moisture regain of wool, the fiber tenacity change, and the associated level of fiber breakage in an opening process. Two kinds of short Merino cardings wool are first converted into draw slivers, which are then opened at different opening levels on an open-end rotor spinner. The draw slivers are free from vegetable matter contamination in order to limit the number of variables in this study. The results indicate that as the ppf value increases, the reduction in fiber moisture regain increases linearly. The test of fiber bundle strength reveals that fiber tenacity drops after opening, but this drop is not proportional to the level of fiber opening. Reasons for this disproportion are discussed. Percent of fiber breakage during opening is examined by measuring changes in mean fiber length before and after opening; it also increases linearly with increasing ppf values.

Uji Komparasi Abnormal Return, Trading Volume, Trading Frequency, Dan Bid-Ask Spread Sebelum Dan Sesudah Share Split

2016 ◽  
Vol 8 (2) ◽  
pp. 24-45
Author(s):  
Tania Hayu Safira ◽  
Febryanti Simon
Keyword(s):  
Abnormal Return ◽  
Trading Volume ◽  
Stock Exchange ◽  
Distributed Data ◽  
Trading Frequency ◽  
Bid Ask Spread ◽  
Analysis Technique ◽  
Before And After ◽  
Test Of Hypothesis ◽  
Kolmogorov Smirnov

This study is event study that was conduct to examine the differences of abnormal return, trading volume, trading frequency and bid-ask spread before and after the events of share split. The object of this research is the companies that did share split and listed in Indonesia Stock Exchange in 2008 - 2015. The samples are 30 companies chosen by purposive sampling method. The criteria are the company did not do corporate action right issue, pre-emptive rights, a share dividend and bonus shares in the same year with share split. Event window used in this study was 30 days consisting of 15 days before and 15 days after the share split. Data analysis technique begins with a test of normality using Kolmogorov – Smirnov and transform for unnormally distributed data. Then, test of hypothesis using Paired t – test to compare the differences before and after share split. The results of this study showed that volume trading activity and trading frequency had significant differences before and after the share split. While, variable abnormal return and bid-ask spread had not significant differences before and after the share split. Keywords: Abnormal return, bid-ask spread, share split, trading frequency, trading volume.

ANALISIS KINERJA KEUANGAN PERUSAHAAN PROPERTI YANG TERDAFTAR DI BEI SEBELUM DAN SESUDAH KEBIJAKAN LOAN TO VALUE

2019 ◽  
Vol 4 (1) ◽  
pp. 79-90
Author(s):  
Ghaniy Ridha Prima ◽  
Hermanto Siregar ◽  
Ferry Syarifuddin
Keyword(s):  
Real Estate ◽  
Financial Performance ◽  
Stock Exchange ◽  
Sample Selection ◽  
Test Analysis ◽  
Asset Return ◽  
Return On Equity ◽  
Analysis Technique ◽  
Significant Difference ◽  
Before And After

The purpose of this study is to provide empirical evidence of the effects of the Loan to Value (LTV) policy on the financial performance of property and real estate companies listed on the Indonesia Stock Exchange (IDX). The sample selection uses a purposive sampling method of 42 property and real estate companies that meet the criteria. The research period is divided into 2 namely before the Loan to Value policy (2013-2014) and after the Loan to Value policy (2016-2017) with the Paired Sample t Test analysis technique. The test results show if the current ratio, Return on Asset, Return on Equity and Debt to Asset have significant differences between before and after the LTV policy is applied. While the fast ratio, cash ratio, net profit margin and Debt to Equity did not show a significant difference. Keywords: Financial Performance, Loan to Value, Property and Real Estate, Profitability Ratio, Liquidity Ratio, Solvability Ratio.

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