Adriano Guarnieri

The X-ray transient XTE J1859 + 226 in outburst and quiescence

We present optical photometry and spectroscopy of the X-ray transient XTE J1859+226, obtained during outburst and its subsequent decay to quiescence. Both the X-ray and optical properties are very similar to those of well-studied black hole soft X-ray transients. We have detected three mini-outbursts, when XTE J1859+226 was approaching quiescence, as has been previously detected in the soft X-ray transients GRO J0422+32 and GRS 1009-45. By 2000 August 24 the system had reached quiescence with R = 22.48 ′ 0.07. The estimated distance to the source is ∼11 kpc. Photometry taken during quiescence shows a sinusoidal modulation with a peak to peak amplitude of about 0.4 mag. A period analysis suggests that periods from 0.28 to 0.47 d are equally possible at the 68 per cent confidence level. The amplitude of the quiescent light curve and the relatively low ratio of X-ray to optical flux indicate that the binary inclination should be high. The measured colours during the outburst allow us to obtain the basic properties of the disc, which agrees well with irradiated disc model predictions.

X{ray and optical monitoring of the peculiar source 4U 1700+24/V934 Her ?

We report on ASCA and BeppoSAX X{ray broad band observations of the galactic low-luminosity X{ray source 4U 1700+24 performed on 1995 and 1998, respectively, and on (quasi-)simultaneous ground observations of its optical counterpart, V934 Her, from the Loiano 1.5-meter telescope. In order to better understand the nature of the source we also analyze public archival ROSAT and RXTE data as well as the RXTE ASM light curve of 4U 1700+24; we also re{analyze a 1985 EXOSAT pointing. The optical spectra are typical of a M2 III star; this allows us to determine a revised distance to the object of400 pc. While these spectra do not show either any spectral change between the two epochs or any peculiar feature apart from those observed in normal red giants, the spectroscopic measurements carried out in X{rays reveal a complex and long-term variable spectrum, with a clear soft excess. The X{ray spectral properties of the source are best described by a thermal Comptonization spectrum plus a soft energy (<1 keV) excess, which can be modeled in the form of a blackbody emission with kTBB 1k eV; the latter component is not detected at the lowest source flux levels. The ratio between the two components varies substantially with the source flux. The X{ray emission from the object appears to become harder as its luminosity increases: indeed, the RXTE data acquired during an outburst occurred in October-November 1997 display a hard tail, detected up to 100 keV and modeled with a comptonizing cloud which is hotter and less opaque than that seen in the low intensity state. Apart from erratic shot-noise variability on timescales of tens to thousands of seconds, no signicant properties (such as pulsations or QPOs) are found from the timing analysis of the X{ray light curves extracted from the observations presented here. With the new distance determination, the 2{10 keV X{ray luminosity range spanned in the considered observations lies between210 32 and110 34 erg s 1 .A ll this information, combined with the ndings by other authors, allows us to suggest that the scenario which best describes the object consists of a wide binary system in which a neutron star accretes matter from the wind of a M-type giant star. Implications of such a model are discussed.

SHELL EGG ALBUMEN HEIGHT ASSESSMENT BY FT-NIR SPECTROSCOPY

Fourier transform near-infrared (FT-NIR) spectroscopy was used for quantitative measurements of thick albumen height. By means of a fiber optic probe in direct contact with the shell, non-destructive acquisitions by diffuse reflectance were carried out to establish a model to predict this egg quality index. After breaking the egg and measuring the reference parameter albumen height, transmission acquisitions of the thick portion of the albumen were also performed. The predictive models obtained from the two experiments showed a good correlation in terms of coefficient of determination (R2 = 0.819 for non-destructive analysis, and R2 = 0.764 for transmission measurements) between the spectral data and the thick albumen height. In both cases, about 80% of the eggs that were not used for model development were predicted with a maximum error of ±1 mm.

From TORTORA to MegaTORTORA—Results and Prospects of Search for Fast Optical Transients

To study short stochastic optical flares of different objects (GRBs, SNs, etc.) of unknown localizations as well as NEOs it is necessary to monitor large regions of sky with high-time resolution. We developed a system consisting of widefield camera with field of view of 400–600 sq.deg. which uses TV-CCD with 0.13 s temporal resolution to record and classify optical transients, and a fast robotic telescope aimed to perform their spectroscopic and photometric investigation just after detection. Such two-telescope complex, combining wide-field camera TORTORA and robotic telescope REM, operated from May 2006 at La Silla ESO observatory. Some results of its operation, including first high time resolution study of optical transient accompanying GRB and discovery of its fine time structure, are presented. Also, prospects for improving the efficiency of such observations are given, and a project of a next generation wide field monitoring system, the MegaTORTORA, is described.

Physical-Mechanical Modifications of Eggs for Food-Processing During Storage

Physical-mechanical properties of egg constituents and their modifications during storage and poststorage greatly influence the efficiency of food processing, such as the separation of white and yolk by mechanical shelling. Thick albumen height, Haugh unit, yolk index and vitelline membrane-yolk system strength of eggs from Hy-Line White and Lohmann Brown hens were analyzed during 7 mo of storage at 0 degrees C performing 3 poststorage treatments: i) immediately after refrigeration, T1; ii) after a further 6 h at 18 degrees C after refrigeration, T2; and iii) after a week at 18 degrees C after refrigeration, T3. For all qualitative parameters considered, this last poststorage treatment appeared to be the factor that produced the highest decrements; with respect to the first poststorage treatment, a further week at 18 degrees C after refrigeration can involve mean decreases of about 19, 14, 14, and 16% in thick albumen height, Haugh unit, yolk index, and vitelline membrane-yolk system strength (in terms of maximum force), respectively. During about 7 mo of storage at 0 degrees C, the latter parameter decreases, on average, by 10%. Increasing the storage time, physical-mechanical behavior was sometimes divergent from the observed trends.

Rapid screening of fatty acid alkyl esters in olive oils by time domain reflectometry.

The main aim of the present research is to assess the possibility of quickly screening fatty acid alkyl esters (FAAE) in olive oils using time domain reflectometry (TDR) and partial least-squares (PLS) multivariate statistical analysis. Eighteen virgin olive oil samples with fatty acid alkyl ester contents and fatty acid ethyl ester/methyl ester ratios (FAEE/FAME) ranging from 3 to 100 mg kg(-1) and from 0.3 to 2.6, respectively, were submitted to tests with time domain resolution of 1 ps. The results obtained in test set validation demonstrated that this new and fast analytical approach is able to predict FAME, FAEE, and FAME + FAEE contents with R(2) values of 0.905, 0.923, and 0.927, respectively. Further measurements on mixtures between olive oil and FAAE standards confirmed that the prediction is based on a direct influence of fatty acid alkyl esters on the TDR signal. The suggested technique appeared potentially suitable for monitoring one of the most important quality attribute of the olive oil in the extraction process.

Fruit Damage Assessment in Peach Packing Lines

In order to assess the effects of mechanical handling on peaches, the impacts measured in Italian packing lines using an instrumented sphere were emulated in the laboratory by means of a simple drop-test device. Samples of Big Top, Caldesi 2000, Centry, and Rich Lady peaches were subjected to impacts representative of the conditions observed at the critical points in packing lines: the drop onto the conveyor belt from the dry bin dumper, the entrance into the counter-basket filler, and at the beginning of the filling of the mini-bin. A test was also carried out to assess the effects on the damages of repeated drops onto the same point of the surface of the fruits. At the highest impact level (180 g, 2.20 m/s), at the beginning of the filling of the mini-bin, damaged fruit did not exceed 18% and the average dimension of the flesh damages did not exceed 10 mm in diameter (Big Top) and 6 mm (Centry) in depth. In general, repeated drops did not seem to cause substantial additional damage. However, they did cause an increase in percentage of damaged fruits for Centry and for the dimension of the alterations for Rich Lady. Considering the severity of the test, the low number of fruits subjected to high impacts by the mini-bin filler and the kind of the damages, the packing lines studied in the present research should not produce an appreciable commercial damage to the ready-to-eat fresh peaches.

TORTORA discovery of Naked‐Eye Burst fast optical variability

Features characterizing gamma‐ray bursts in the different spectral bands may be a clue for the nature of their inner engine. Up to now, only several bursts have been observed in optical band during the gamma activity, and the only one—GRB080319B—was covered from rise till fall with high temporal resolution. Here we discuss these data, acquired with TORTORA fast wide‐field monitoring optical camera, as well as results of its analysis.The camera observed the position of Naked‐Eye Burst, GRB080318B, before, during and after the trigger. It detected the fast rise of optical emission, which reached the peak of V 5.3 at the eighteenth second, had a complex evolution till T+43s and monotonously faded then. The brightest part of the light curve contains two 15–20 s segments with different fluxes, each having two clearly‐seen peaks of 5–8 s duration; all four peaks look quasi‐periodic with separation of 9 s. There is no clear evidence of any sub‐second variability. However, there are signs of quasi‐periodic variab...

Wide and Fast: Monitoring the Sky in Subsecond Domain with the FAVOR and TORTORA Cameras

In order to detect and investigate short stochastic optical flares from a number of variable astrophysical objects (GRBs, SNe, flare stars, CVs, X-Ray binaries) of unknown localizations as well as near-earth objects (NEOs), both natural and artificial, it is necessary to perform the systematic monitoring of large regions of the sky with high temporal resolution. Here we discuss the criteria for a system that is able to perform such a task and describe two cameras we created for wide-field monitoring with high temporal resolution—FAVOR and TORTORA. Also, we describe basic principles of real-time data processing for the high frame rates needed to achieve subsecond temporal resolution on a typical hardware.

MECHANICAL BEHAVIOR AND DAMAGE OF PINK LADY APPLES

Research was conducted to investigate the type of damage and mechanical behavior of Pink Lady apples during post-harvest operations. Samples of apples of this new cultivar were subjected to drop tests to simulate the kind of impact recorded in Italian sorting and packing lines by means of an instrumented sphere. A simple device with an acceleration transducer mounted on the apple and an acquisition system were used to cause an impact and to describe the mechanical behavior of the fruit. Data were treated statistically employing logistic regression and multiple linear regression analyses to determine correlations between probability, characteristics of damage and parameters describing impact and characteristics of the apples. A logit model was used to assess the probability of damage occurring to fruit. In this model (R2 L = 0.380) the characteristics of the impact and the firmness of the flesh of the fruit were found to be significant. The kind of damage appeared to be significantly influenced by the impact level and, in general, by the mass, the sugar content and the curvature radius at the point of impact on the apples. Coefficients of determination of the models to predict characteristics of damage were from 0.104 to 0.312. The curvature radius was correlated with peak acceleration of the apples, too (R2 = 0.210). Although the prediction power of the statistical models was low, they were useful to check significance and analyze correlations between parameters.