Giulio Fanti

The double superficiality of the frontal image of the Turin Shroud

Photographs of the back surface of the Turin Shroud were analysed to verify the existence of a double body image of a man. The body image is very faint and the background not uniform; i.e., the signal-to-noise ratio is lower than one. Therefore, image processing, developed ad hoc, was necessary to highlight body features. This was based on convolution with Gaussian filters, summation of images, and filtering in spatial frequency by direct and inverse bidimensional Fourier transformations. Body features were identified by template matching. The face and probably also the hands are visible on the back of the Turin Shroud, but not features related to the dorsal image.

Regression analysis with partially labelled regressors: carbon dating of the Shroud of Turin

The twelve results from the 1988 radio carbon dating of the Shroud of Turin show surprising heterogeneity. We try to explain this lack of homogeneity by regression on spatial coordinates. However, although the locations of the samples sent to the three laboratories involved are known, the locations of the 12 subsamples within these samples are not. We consider all 387,072 plausible spatial allocations and analyse the resulting distributions of statistics. Plots of robust regression residuals from the forward search indicate that some sets of allocations are implausible. We establish the existence of a trend in the results and suggest how better experimental design would have enabled stronger conclusions to have been drawn from this multi-centre experiment.

Coloring linens with excimer lasers to simulate the body image of the Turin Shroud

The body image of the Turin Shroud has not yet been explained by traditional science; so a great interest in a possible mechanism of image formation still exists. We present preliminary results of excimer laser irradiation (wavelength of 308 nm) of a raw linen fabric and of a linen cloth. The permanent coloration of both linens is a threshold effect of the laser beam intensity, and it can be achieved only in a narrow range of irradiation parameters, which are strongly dependent on the pulse width and time sequence of laser shots. We also obtained the first direct evidence of latent images impressed on linen that appear in a relatively long period (one year) after laser irradiation that at first did not generate a clear image. The results are compared with the characteristics of the Turin Shroud, reflecting the possibility that a burst of directional ultraviolet radiation may have played a role in the formation of the Shroud image.

S.A.M., the Italian Martian Simulation Chamber

The Martian Environment Simulator (SAM “Simulatore di Ambiente Marziano”) is a interdisciplinary project of Astrobiology done at University of Padua. The research is aimed to the study of the survival of the microorganisms exposed to the “extreme” planetary environment. The facility has been designed in order to simulate Mars’ environmental conditions in terms of atmospheric pressure, temperature cycles and UV radiation dose. The bacterial cells, contained into dedicated capsules, will be exposed to thermal cycles simulating diurnal and seasonal Martian cycles. The metabolism of the different biological samples will be analysed at different phases of the experiment, to study their survival and eventual activity of protein synthesis (mortality, mutations and capability of DNA reparing). We describe the experimental facility and provide the perspectives of the biological experiments we will perform in order to provide hints on the possibility of life on Mars either autochthonous or imported from Earth.

Analysis of dynamic performances of hasi temperature sensor during the entry in the Titan atmosphere

Abstract The performances of the temperature sensors of the HASI instrument ( Fulchignoni et al., 1996 ) have been analyzed using a numerical model, validated by comparison with the results of various experimental tests. The idea of implementing a numerical model of the sensors arose when the tests for the dynamic characterization of the thermometer ( Angrilli et al., 1996a ) showed that the behavior was quite different from that of a first order system. Modeling the sensor only by means of the time constant of the sensing wire does not account for the effect of the mechanical structures thermal inertia. A more accurate dynamic characterization of the sensor requires three parameters, that depend on the thermo-fluid environment. Actually the sensor during the descent in Titan atmosphere changes its behavior dramatically according to the changes in velocity and atmospheric conditions. The most relevant effect is the change of the frequency bandwidth of the sensor, leading to a variation of the actual spatial resolution in the measured temperature profile. Using the numerical model of the sensors together with the profile of temperature, pressure and composition given in literature ( Lellouch et al., 1989 ) for the Titan atmosphere, the dynamic characteristics of the sensor at various altitude have been determined. The choice of using numerical simulation instead of experimental tests on the unit depends on the consideration that to accomplish similitude, both Re and Nu numbers must be tuned. A complete experimental characterization of the sensor would require a series of tests in a wind tunnel with various fluid velocities and thermal conductivity. The most relevant results are related to the large difference between the frequency bandwidth of the sensors at the beginning of the measurements, where the speed is high, but the density is low with respect to those at the end. Due to the changes in density, the response of the sensor is slow when the velocity of the probe is high, at the beginning of the measurements, in this case the sensor could detect only very large atmospheric structures. The maximum in thermometer response speed is obtained during the last part of the descent, when the velocity is low but the foreseen density is high, therefore in this phase the sensor will be able to detect structures of small dimension. Starting from the results of these dynamic performances a new sensor has been devised, the dynamic performances seem to be promising, showing an improvement in the frequency bandwidth of one decade, and though its realization is only at the beginning, it can be considered as a candidate in the planning of future missions.

Multi-parametric micro-mechanical dating of single fibers coming from ancient flax textiles

A new micro-mechanical method for textiles dating was applied to flax fabrics. Notwithstanding that environmental factors like temperature and humidity can influence the mechanical parameters of ancient textiles, the method shows a relatively stable trend if some previous analysis is done to eliminate degraded samples. This method is based on a multi-parametric analysis of single fibers tested on a proper machine designed and calibrated for the purpose. Single fibers mounted on special supports are submitted to mechanical test consisting of multiple stress–strain cycles. The parameters sensitive to aging are tensile strength, Young modulus, and loss factor, the last two evaluated during particular phases of loading cycles. Five different calibration curves relating age to these mechanical parameters are determined by using a series of eleven textiles of known age from 3250 BC to 2000 AD that passed a proper pre-selection. The resulting age of the textiles derives from a combination of five independent dating. The relatively small number of textiles used for the analysis, due to the fact that it is not easy to find ancient textiles, gave results that can be improved by future analyses addressed to test a larger number of samples. For the moment, the relative standard uncertainty of the method is about 200 years but future test could reduce this uncertainty. This relatively simple method can also be useful to museums which wish to date themselves ancient textiles at low cost.

The Halley multicolour camera

The Halley multicolour camera is a high-resolution imaging system on board Giotto. The fast spin of this spacecraft (15 RPM) required a unique and highly specialised design complex fully autonomous operation. Design criteria and trade-offs and operational aspects are emphasised in this instrument description. Actual performance numbers are given whenever available. The imaging quality is demonstrated by sample images taken from the Earth and the comet.

First results of performance test of temperature sensors of HASI instrument on Cassini/Huygens mission

First results about the performance of the temperature sensors (TEM) of Huygens Atmospheric Structure Instrument (HASI) obtained during Flight Model test campaign are presented and discussed. TEM belongs to the STUB subsystem of HASI, which is a multidisciplinary experiment package dedicated to the investigation of Titan atmosphere during the descent of the Huygens probe. TEM sensors are described, their characteristics and performances discussed and the data of thermal tests carried out at subsystem level and at probe level evaluated. From this preliminary analysis it seems that the sensors are suited to achieve the scientific objective of HASI experiment if post flight data correction is appropriately done.

Comments on a stochastic hypothesis about the body image formation of Turin Shroud

The publication of a very recent paper in this Journal is based on facts reported in dated literature that have been recently revised. It seems therefore appropriate to evidence which is the news related to the more recent discoveries on the Turin Shroud. An improvement of the paper based on these facts is also recommended. The stochastic process evidenced in this paper to explain why colored fibers appear side-by-side with noncolored fibers in the Shroud image threads is interesting and it should be related to the physical phenomena that could have produced the body image.

Colouring fabrics with excimer lasers to simulate encoded images: the case of the Shroud of Turin

The faint body image embedded into the Turin Shroud has not yet explained by traditional science. We present experimental results of excimer laser irradiation (wavelengths 308 nm and 193 nm) of a raw linen fabric and of a linen cloth, seeking for a possible mechanism of image formation. The permanent coloration of both linens is a threshold effect on the laser beam intensity and it can be achieved only in a surprisingly narrow range of irradiation parameters: the shorter the wavelength, the narrower the range. We also obtained the first direct evidence of latent images impressed on linen that appear in a relatively long period (one year) after a laser irradiation that at first did not generate a clear image. The results are compared to the characteristics of the Turin Shroud, commenting the possibility that a burst of directional ultraviolet radiation may have played a role in the formation of the Shroud image.