IMEKO Event Proceedings

Page 788 of 855 Results 7871 - 7880 of 8545

C. Casavola, A. Cazzato, V. Moramarco

Friction Stir Welding (FSW), developed at The Welding Institute (TWI) in 1991, is a new solid-state welding process. In this technique, the material does not reach the fusion but the joint is the consequence of the plasticization resulting from the generation of heat by friction and the stirring action of the pin on the material due to the rotation and the displacement of a non-consumable tool. Thus, the FSW reaches temperatures lower than those reached by conventional fusion welds. Laser Assisted Friction Stir Welding (LAFSW) is a combined welding technique in which the FSW is assisted, during the weld, by the pre-heating of a de-focalized laser. This technique leads higher welding speeds, lower clamping force and it has some benefits for tool wear. Nevertheless the control of the temperature field is fundamental to guarantee a high quality joint. In this work FSW and LAFSW bead on plate tests were conducted on 6 mm thick 5754 H111 aluminum alloy plates with constant tool rotation and welding speed. Thermographic images were acquired to compare the effect on the temperature field of laser source distance from the tool and laser power.

R. Morello, C. De Capua
Thermography for Non-Invasive Diagnosis of Conservation State of Archeological Discoveries

The present paper discusses about the use of active thermography to assess the conservation state of archaeological discoveries and historic sites. The preservation of historical and archaeological heritage is today an open issue due to the amount of sites and to the costs of the current methodologies and technologies used. As a consequence, interventions are made only when a deterioration process is in progress. The use of non-invasive techniques is essential for such kind of applications in order to not compromise the integrity of the find. Thermography is a contactless measurement technique able to monitor thermal response of any object even during dynamical conditions. Its basic principle allows to evaluate the presence of humidity, cracks, variation of thickness, structural integrity, exposition to heat sources, previous restoration works not visible at naked eye. Therefore, this technique can be used to evaluate the integrity of buildings, statues, paintings, artifacts, etc…
The paper aims to describe how this technique is used to diagnose, monitor and preserve the conservation state of archaeological discoveries, sites and ruins. The considered application case concerns the Riace Bronzes, two bronze statues of the first half of the V century B.C. preserved in the National Museum of Magna Græcia, Reggio Calabria, Italy.

Rodica-Mariana Ion, Radu Setnescu, Tanta Setnescu, Anca Irina Gheboianu, Gabriel Vasilievici, Sorin Tincu
Thermoluminescence dating and microstructural characterization of archaeological ceramic samples from Corvins Castle area

Some ceramics samples from Corvins Castle area - Coart Area, in different weathering stages, have been analyzed in this paper by different analytical techniques: XRD, thermal analysis (TG, DTG), porosity and thermoluminescence (TL) dating. For identification of the technology employed in the pottery production, the firing temperature could be determined through the presence of some minerals (evidenced by XRD), quartz and calcite being the most important ones. Crushed calcite is a good indicator, because it is present in the ceramics which have been tired up to 750° C (under oxidized atmosphere). By TL the nature of the crystalline network could be detected, ceramics consist of a number of crystalline inclusions (mainly quartz and feldspar) embedded in the ceramic matrix. The peak related to 343° C is always found in quartz. The date obtained by TL technique was in good agreement with the date assigned by archaeologists.

Laura Guidorzi, Fulvio Fantino, Elisabetta Durisi, Marco Ferrero, Alessandro Re, Luisa Vigorelli, Lorenzo Visca, Monica Gulmini, Giovanni Dughera, Giuseppe Giraudo, Debora Angelici, Elisa Panero, Alessandro Lo Giudice
Thermoluminescence dating laboratory improvements tested on an archaeological rescue site in Trino, Vercelli province, Italy.

Thermoluminescence (TL) is a reliable radiation-based technique for the dating and authentication of ceramic objects, allowing the evaluation of the time elapsed since their last exposure to high temperatures (e.g. firing in kiln or later fire events). The TL laboratory developed in the last decade at the Physics Department of the University of Torino, currently operating within the INFN (National Institute of Nuclear Physics) CHNet network, is presented. The 10-years-long experience in the field resulted in the enhancement of the procedures, with the development of customised α and β irradiation systems and the optimisation of sampling approach and chemical pre-treatment. In collaboration with TecnArt S.r.l., the improved procedures were employed for dating two structures from a rescue archaeological site in the Vercelli province (Italy).

Ho Sun Shin,Joon Sung Lee,Seong Gi Jeon,Jin Yu, Jae Yong Song

We have fabricated a MEMS device on suspended silicon nitride in order to measure the thermoelectric properties of single nanowire. The temperature gradient was generated by a nanoheater and the temperatures of thermometers were calibrated and measured. Seebeck coefficient and electrical conductivity of single Bi2Te3 nanowire with a 70 nm-diameter were measured in the temperature range of 50 K to 400 K. Based on the simulation results of the temperature distribution over the MEMS structure, the method of calibrating the temperature and measurement uncertainty are discussed.

D. Crescini, D. Marioli, A. Taroni

This paper illustrates the design and the development of a thick-film mass flow sensor based on the frequency shift of a resonating ceramic structure. The mechanical oscillator realized uses a measurement principle of thermoanemometric type. The sensor can measure mass flows up to 15 × 104 sccm (sccm: 10 sccm = 0.17 mg/s), with high sensitivity. Here we report on the first prototype consisting of a beam 0.254 mm thick , 4 mm large and 17 mm long, in which the temperature variations induced by flow, affect the resonance frequency. Predicted and measured values for the shift of the resonance frequency agree well. At the first flexural mode of vibration of 3.5 kHz and at an average temperature rise of the substrate of 100 ° C, a frequency change of 500 Hz in the mass flow range from zero to 15 × 104 sccm can be measured. Indications are proposed for reducing the time response and increasing the sensitivity.

A. Lopes Ribeiro, Helena G. Ramos, J. Couto Arez

This paper describes the implementation of a device that measures the thickness of metallic plates. A pancake coil for magnetic field sinusoidal excitation is used and detection is performed with a bridge giant magneto-resistor sensor. The paper uses the theory of the linear transformer to explain the liftoff effect with a special attention to the point of intersection phenomenon.

M. Malesa, I. Mazurkiewicz, A. Lebek, J. Michonski, K. Malowany, M. Kujawinska
Thickness measurements of corroded district heating pipelines with utilization of Structured Light Technique

In this paper we present application of the Structured Light Illumination method for measurements of thickness of corroded district heating pipelines. The presented methodology allowed determination of the depth of pitting corrosion centres on both inner and outer sides and in each point of the pipe. Obtained data was consequently utilized for statistical analysis of corrosion growth process. The conclusions about the pitting corrosion process, as well as possible development of the presented methodology are discussed in conclusions.

S. Minamiguchi, S. Usuki, S. Takahashi, K. Takamasu
Thin film thickness measurement for evaluation of residual layer of nano-imprint lithography using near-field optics

Since a thin resin film with thickness of several 10nm remains as a residual film between the imprinted patterns and the substrate in the nano-imprint lithography process, it should be eliminated by reactive ion etching. To implement the etching process with high accuracy and to maintain the original patterns for realizing NIL as a highly reliable lithography process of semiconductor, it is seriously necessary to measure the thickness of the residual resin film before the etching process. In this article, we proposed a novel optical measurement method for the residual film thickness based on the near-field optics. As a result, the near-field optical responses are affected in relation to the film thickness and a distance between the resin surface and a fiber apex. We concluded that it is possible to measure the thin film thicknesses within 80nm with a few nm resolution by evaluating the near-field optical responses.

Jun, L., Fang, X., Shang, T.
Thinking and practicing of National Quality Infrastructure in China

Quality has always been an important issue, and it is a hot topic in the past in all parts of the world. The globalization of the markets continues its rapid pace and as it is shaped by technological developments, more and more governments are carefully reconsidering the overall arrangement of their National Quality Infrastructure, NQI. This paper covers the concept of NQI, the relationship between NQI elements, a case of application of NQI to a food productive chain and the development prospect in China.

Page 788 of 855 Results 7871 - 7880 of 8545