In situ assessment of structural timber elements of a historic building by infrared thermography and ultrasonic velocity

Kandemir-Yucel, A.
Tavukçuoğlu, Ayşe
Caner-Saltik, E. N.
The infrared thermography (IRT) and the ultrasonic velocity measurements (UVM) promise to be particularly important to assess the state of deterioration and the adequacy of the boundary and microclimatic conditions for timber elements. These non-destructive methods supported by laboratory analyses of timber samples were conducted on a 13th century monument, Aslanhane Mosque in Ankara, Turkey. The combined interpretation of the results was done to assess the condition of structural timber elements in terms of their state of preservation, the dampness problems and the recent incompatible repairs affecting them. Results indicated that moist areas in the structure were associated with roof drainage problems and the repairs undertaken with cement-based mortars and plasters and oil-based paints. Juxtaposition of the IRT and UVM together with laboratory analyses was found to be useful to assess the soundness of timber, enhanced the accuracy and effectiveness of the survey and facilitated to build up the urgent and long-term conservation programs.


Electronic structure of carbon nanotubes: AM1-RHF calculations
Erkoç, Şakir; Turker, L (Elsevier BV, 1999-07-01)
We have investigated the electronic structure of optimized open-ended single-wall carbon nanotubes with armchair and zigzag geometries. The calculations were performed using AM1-RHF semiempirical molecular orbital method. It has been found that the density of states of the zigzag model is more sensitive to the tube size than that of the armchair model.
A theoretical study of chemical doping and width effect on zigzag graphene nanoribbons
Pekoz, Rengin; Erkoç, Şakir (Elsevier BV, 2009-12-01)
The energetics and the electronic properties of nitrogen- and boron-doped graphene nanoribbons with zigzag edges have been investigated using density functional theory calculations. For the optimized geometry configurations, vibrational frequency analysis and wavefunction stability tests have been carried out. Different doping site optimizations for a model nanoribbon have been performed and formation energy values of these sites revealed that zigzag edgesite for both of the dopants were the most favorable ...
Assessment of large format InP/InGaAs quantum well infrared photodetector focal plane array
Ozer, S; Cellek, OO; Beşikci, Cengiz (Elsevier BV, 2005-10-01)
We report the fabrication and characteristics of large format (640 x 512) InP/In0.53Ga0.47As long wavelength infrared (LWIR) quantum well infrared photodetector (QWIP) focal plane array (FPA). The FPA, which is hybridized to a read-out integrated circuit having a charge capacity of 1.1 x 10(7) electrons, yielded a mean noise equivalent temperature difference (NETD) of similar to 40 mK at a cold finger temperature as high as 77 K. The performance of the FPA, being comparable to that of AlGaAs/GaAs QWIP FPAs,...
Direct measurement of molecular stiffness and damping in confined water layers
We present direct and linear measurements of the normal stiffness and damping of a confined, few molecule thick water layer. The measurements were obtained by use of a small amplitude (0.36 Angstrom), off-resonance atomic force microscopy technique. We measured stiffness and damping oscillations revealing up to seven molecular layers separated by 2.526+/-0.482 Angstrom. Relaxation times could also be calculated and were found to indicate a significant slow-down of the dynamics of the system as the confining...
On the theory of internal photoemission in heterojunctions
Aslan, B; Turan, Raşit (Elsevier BV, 2005-08-01)
The theory of internal photoemission in semiconductor heterojunctions has been reviewed and the existing model has been extended by incorporating the effects of the difference in the effective masses in the active region and the substrate, non spherical-nonparabolic bands, and the energy loss per collisions. This complete model has been applied to describe the experimental results obtained from Si1-xGex/Si heterojunction infrared photodetectors. The barrier heights (correspondingly the cut-off wavelengths) ...
Citation Formats
A. Kandemir-Yucel, A. Tavukçuoğlu, and E. N. Caner-Saltik, “In situ assessment of structural timber elements of a historic building by infrared thermography and ultrasonic velocity,” INFRARED PHYSICS & TECHNOLOGY, pp. 243–248, 2007, Accessed: 00, 2020. [Online]. Available: