Bonding assessment of semi-precast slabs subjected to flexural load and differential shrinkage

2019 ◽  
Vol 187 ◽  
pp. 25-33 ◽  
Author(s):  
S.S.E. Lam ◽  
V. Wong ◽  
R.S.M. Lee
Author(s):  
Songquan Sun ◽  
Richard D. Leapman

Analyses of ultrathin cryosections are generally performed after freeze-drying because the presence of water renders the specimens highly susceptible to radiation damage. The water content of a subcellular compartment is an important quantity that must be known, for example, to convert the dry weight concentrations of ions to the physiologically more relevant molar concentrations. Water content can be determined indirectly from dark-field mass measurements provided that there is no differential shrinkage between compartments and that there exists a suitable internal standard. The potential advantage of a more direct method for measuring water has led us to explore the use of electron energy loss spectroscopy (EELS) for characterizing biological specimens in their frozen hydrated state.We have obtained preliminary EELS measurements from pure amorphous ice and from cryosectioned frozen protein solutions. The specimens were cryotransfered into a VG-HB501 field-emission STEM equipped with a 666 Gatan parallel-detection spectrometer and analyzed at approximately −160 C.


2021 ◽  
Vol 1019 ◽  
pp. 205-210
Author(s):  
Deepika S. Singraur ◽  
Bhushan T. Patil ◽  
Vasim A. Shaikh

The cooling process is an essential aspect while designing for uniform heat transfer between the mold and the molded part. Improper design and placement of cooling channels result in non-uniform cooling and thus results in differential shrinkage and warpage on the final product. The installation of the channels yet plays a crucial role in the cooling of the part. Conforming channels that are placed at an optimum distance from the part to enhance the cooling process. In this paper, the performance parameters of straight drilled channels are compared with the conformal cooling channels for an electric alarm box. The analysis indicates that the conformal cooling method improved and enhanced the cooling process and reduced the defects like warpage and differential shrinkage by 25.5% and 28.0% respectively.


Author(s):  
Amy Dimmerling ◽  
Richard A. Miller ◽  
Reid Castrodale ◽  
Amir Mirmiran ◽  
Makarand Hastak ◽  
...  

Precast bridge girders can be made continuous for live loads with the provision of a moment connection over the supports. NCHRP Project 12–53 examined methods for making this type of moment connection. This is usually done by placing negative moment reinforcement in a cast-in-place deck over the support and by placing a diaphragm between the girder ends. To counteract positive moments caused by creep and shrinkage, positive moment connections are often provided at the girder ends. An experimental study of the strength of six different positive moment details, involving either extended strand or extended bar, was conducted. The results showed that all details had sufficient strength. Details using additional stirrups in the diaphragm were found to have increased ductility, and the use of horizontal web bars increased capacity. Two full-size specimens were tested to determine the level of continuity after cracking occurs at the joints. One of these specimens was also monitored for several months to determine the effects of creep, shrinkage, and temperature on the connections. It was found that expansion and contraction of the deck caused by heat of hydration and changes in ambient temperature greatly affected the system. However, an anticipated formation of negative moment caused by differential shrinkage did not occur. Even when the positive moment connection was near failure, the system maintained 70% continuity even when cracked. The system was also found to have adequate negative moment capacity.


1986 ◽  
Vol 5 (3) ◽  
pp. 349-352 ◽  
Author(s):  
D. S. Smith ◽  
A. Smith

2014 ◽  
Vol 18 (2) ◽  
pp. 96-107
Author(s):  
Abdel-Fattah M. Seyam ◽  
Sanaa S. Saleh ◽  
Mamdouh Y. Sharkas ◽  
Heba Z. AbouHashish

A range of intricate finished seamless shaped garments have been developed with the aim to fit predetermined sizes. The shape is created by using woven tubular fabrics with differential shrinkage in the same garment. The differential shrinkage is obtained by altering the fabric construction parameters at strategic locations along the length of the garment. The construction arameters include different weaves (plain, 2/2 basket, 1/3 twill, 2/2 twill, and crowfoot), weft densities, weft yarn counts, and weft yarns with different shrinkages (cotton, cotton that contains spandex, and cotton/polyester yarns). The weft yarn tension is used as an additional parameter to influence fabric shrinkage. A total of thirty-three woven fabrics are formed to establish the relationship between the construction parameters, weft tension, and shrinkage of the finished woven fabric. The relationship is used to produce a range of intricate garments with inherent shapes and predetermined sizes.


2009 ◽  
Vol 43 (1-2) ◽  
pp. 297-308 ◽  
Author(s):  
J. C. Amba ◽  
J. P. Balayssac ◽  
C. H. Détriché

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