Detection of the thickness of scale on the inner surface of water pipes by infrared thermography
The infrared thermography technique developed in the present study was successfully applied to determine the scale thicknesses of the steel pipe. We aim to estimate the thickness of the scale on the inner surfaces by calculation of the maximum temperature of the infected pipe heated surface. Dimensions of the pipe and those of the layer of scale are taken as geometrical parameter. We have studied the effect of each one on the thermal response of the considered structure. These information are important for determining dangerous state of water distribution network.
FORMATION OF CaCO3 PARTICLE AND CONDUCTIVITY OF Na2CO3 AND CaCl2 SOLUTION UNDER MAGNETIC FIELD ON DYNAMIC FLUID SYSTEM
Hard  water  causes  the  CaCO3  scale  formation  on  the  pipe  walls and  heat  exchanger  equipments  in  industrial  or domestic  water  processes.  A  great  number  of  experimental  researches  on  the  prevention  of the  CaCO3  precipitation process  by  magnetic  field  have  been  carried  out.  In  this  research,  Na2CO3  and  CaCl2  solutions  was  magnetized  in  the circulated  flow  condition  (dynamic  fluid  system).  The  velocity  of  fluid  and  the  circulation  time  was  modified  to examine  its influences  to  the  magnetization  process.  CaCO3  content  was measured  by  titration  method  of  EDTA complexometry.  Conductivity  test  was  conducted  to  find  out  hydrate  ion  bonding.  The  results  showed  that magnetization increased the CaCO3 formation and the optimum process reaches for 10 minutes circulation on 0.554 m/s of flow rate. Magnetic field decreases the conductivities of Na2CO3 and CaCl2  solution, hence reduced the ion hydrate bonding. These results showed that magnetization on Na2CO3 and CaCl2 ionic solution was effective in controlling the CaCO3 formation by increasing CaCO3 precipitation.
Experimental study on bond behavior between high-strength grout and deformed steel bars
Abstract Engineers use high-strength grout to connect precast concrete members for its low shrinkage and good fluidity. This paper designed 87 central pull-out specimens using the control variable method to investigate the influence of factors on the rebar-grout bond property such as compressive strength, steel grade, bar diameter, transverse stirrups, and bond length. The test result showed that improving grout compressive strength (85.8 MPa–122.7 MPa) cannot improve the bond strength, which was different from the previous conclusions of concrete pull-out tests. Simplified formulas were presented for calculating the characteristic values of bond strength, residual strength, peak slip, and relative slip of load-holding platform based on parameter analysis. Then, a constitutive model was proposed to predict the full-range bond stress-slip curve of high-strength grout and steel bar specimens from bearing to failure. Finally, FEA models were established to evaluate the applicability and accuracy of the constitutive model.