A Numerical Study on Temperature Distribution of Line Heated Anisotropic Carbon Fiber Composites

Earlier we have described the various uses of infrared line scanner based thermal nondestructive testing equipment [1]. Time constants of measurements made with these kind of equipment are very suitable for testing carbon fiber composites. Scanning a line heat source over a sample surface causes a nonuniform temperature distribution in the sample. In addition to the heat flow normal to the surface, lateral heat flow exists in the surface plane. In the case of carbon fiber composites with a specific oriented structure, the surface temperature distributions depend on the direction where the line source moves. Generally, this is true of any sample having anisotropic thermal conductivity. In oriented carbon fiber composites the bulk thermal conductivity can be considered anisotropic, because the heat transfer in the composite is different in the direction of the fibers compared to perpendicular directions [2,3]. Varis et al. have discussed these phenomenon briefly with the testing of carbon fiber tubes using numerical methods [4]. Here, we represent a more detailed numerical analysis of the effects of line heating on a sample having anisotropic thermal conductivity

Analysis of Heat Input Effects in Passive Thermographic NDE

The use of digital imaging techniques for analysing and enhancing IR video frames in thermographic NDE [1–6] allows some improvement in resolution of surface temperature contrast. Of equal importance, however, to the magnitude and longevity of the generated contrast is the magnitude and length of the function governing the input heating rate and source impedance [7], In thermogaphic testing the limiting factor is usually the maximum temperature rise (or drop) over a given time span that the heated (cooled) face of the sample can be subjected to without damage occuring. In this study single step and profiled radiative heat pulses have been assessed numerically and experimentally and compared to contact heating (as with a hot liquid in a flexible bag). The detrimental effects of convective and radiative surface heat losses have been examined and their significance to the testing of low and high diffusivity materials assessed. All results presented here are for the two-sided testing configuration although, in principle, the results are applicable to single sided testing also.</p

ECTOPARASITES IN CULTIVATED BUJURQUI (CICHLASOMA AMAZONARUM; PISCES: CICHLIDAE) REARED IN FISH PONDS

Los objetivos del presente estudio fueron identificar y establecer las frecuencias de ectoparásitos en Cichlasoma amazonarum (Pisces: Cichlidae) criados en estanques en la zona de Iquitos, Perú, entre octubre y diciembre de 2004. Se colectaron ectoparásitos de tegumento y branquias en 227 peces. Los parásitos fueron teñidos con Hematoxilina de Delafield. La frecuencia de infecciones por ectoparásitos fue de 78.0 ± 6.1% de monogeneos y 0.9% de maxillopoda (Crustacea: Branchiura). Dentro de los monogeneos, el 88.1% correspondió a parásitos de la familia Dactylogyridae, 6.2% a la familia Gyrodactylidae y 5.7% a infecciones mixtas de ambas familias. Los maxillopoda encontrados fueron de la especie Dolops geayi. El 80.2% de los peces muestreados presentaron de uno a tres parásitos por individuo, lo que indica niveles bajos que no afectan la salud de los peces. No se encontró una correlación significativa entre las medidas biométricas de los peces con la infección de monogeneos. Los resultados del presente estudio indican que la presencia de monogeneos en cíclidos amazónicos peruanos es común.The aim of the present study was to identify ectoparasites and to establish the frequencies of infections in Cichlasoma amazonarum (Pisces: Cichlidae) raised in artificial ponds in Iquitos, Peru from October to December 2004. Ectoparasites collected from the skin and gills in 225 fish were stained using Delafield Hematoxiline. The frequency of ectoparasites was 78.0 ± 6.1% monogeneans and 0.9% maxillopoda (Crustacea: Branchiura). Among monogenean infections, 88.1% corresponded to parasites of Dactylofyridae family and 6.2% of Gyrodactylidae family, whereas 5.7% to mixed infections of both families. All maxillopoda found were Dolops geayi. One to three parasites per individual were found in 80.2% of the sampled fish, indicating of low parasite burden, which may no affect fish health. There was no significant correlation between biometric measurements and monogeneans infection in C. amazonarum. This study could indicate that monogeneans in Peruvian Amazon cichlids are common

Parallel Imaging of Thickness Variations and Disbonding of Thermal Barrier Coatings by Time-Resolved Infrared Radiometry (TRIR)

Pulsed photothermal radiometry has been shown to be a useful thermally-based nondestructive evaluation technique for various thin films and layered specimens [1,2]. In this method the time development of the surface temperature is studied for both heating and cooling, during and after the application of a step heating pulse of duration, T. In this paper, we show that the method gives quantitative information about layered materials including measurement of coating thickness and the detection and characterization of disbonding between layers. Since all times are monitored, it is not necessary to know the thickness of the coating provided the heating pulse is set longer than the thermal transit time of the coating. As a result, both coating thickness and the integrity of the coating-substrate bond can be determined simultaneously