41 research outputs found
An NMR study on internal browning in pears
Internal browning in pears (Pyrus communis L. cv. Blanquilla) has been studied by NMR and MRI in order to develop a non-destructive procedure for on-line disorder identification. For NMR relaxometry, disordered tissue shows higher transverse relaxation rates compared to sound tissue, especially at higher magnetic field strength and for long pulse spacing. Membrane alteration and therefore tissue disintegration, as well as water evaporation, appear to be the main causes of this response. Correlation between relaxation times and diffusion showed that the proton pools in disordered tissue are grouped into a smaller number of populations compared to sound tissue, also highlighting cell decompartmentation in disordered tissue. At a macroscopic level, fast low angle shot MR images, effective transverse relaxation-weighted (TR 11 ms and TE 3.7 ms) and proton density-weighted (TR 7.6 ms and TE 2.5 ms), were acquired for pears at a rate of 54 mm/s. Images have been discriminated for internal breakdown according to histogram characteristics. Up to 94 and 96% of pears, respectively, were correctly classified in the former and the latter type of images. In this study a minimum value of 12% of tissue affected by breakdown was always clearly identifie
Prospects for the rapid detection of mealiness in apples by nondestructive NMR relaxometry
The potential of nuclear magnetic resonance (NMR) relaxometry for quantitative evaluation of apple mealiness has been investigated. The degree of "mealiness" was defined by several mechanical techniques, including penetration, compression and shear rupture as well as by the BRIX (soluble solids) and juiciness levels. These data were correlated with both magnetic resonance imaging (MRI) and NMR water proton transverse relaxation time measurements on a fruit-by-fruit basis. It was found that increasing mealiness caused a systematic increase in the transverse relaxation rate. The potential for rapid, on-line NMR/MRI detection of apple mealiness is discussed
Prospective of Innovative Technologies for Quality Supervision and Classification of Roasted Coffee Beans
Color sorting is the major procedure employed for establish roast degree of coffee beans. However, color-based procedures have been proven to be ineffective, since coffee beans roasted to different degrees can present the same average readings in light reflectance measurements with significant quality variations. Besides to color, other major changes in beans are volume (swell), mass, form, bean pop and density. Eight samples of arabica coffee from Colombia and Guatemala have been roasted under slightly different conditions of time and temperature in order to obtain the same color classification. Sample analysis of data from nuclear magnetic resonance relaxometry show differences between samples in T1 and T2 parameters at cellular and subcellular level, and image analysis carried out on X-ray μCT leading to microestruture images corroborate differences in porosity and fissures presence among them, proving the potentiality of these technological solutions for sensing the microstructure of coffee to provide tools to enhance the roasting process
Planck early results. VI. The High Frequency Instrument data processing
We describe the processing of the 336 billion raw data samples from the High Frequency Instrument (HFI) which we performed to produce six
temperature maps from the first 295 days of Planck-HFI survey data. These maps provide an accurate rendition of the sky emission at 100, 143,
217, 353, 545 and 857GHz with an angular resolution ranging from 9.9 to 4.4 . The white noise level is around 1.5 μK degree or less in the 3 main
CMB channels (100–217 GHz). The photometric accuracy is better than 2% at frequencies between 100 and 353 GHz and around 7% at the two
highest frequencies. The maps created by the HFI Data Processing Centre reach our goals in terms of sensitivity, resolution, and photometric
accuracy. They are already sufficiently accurate and well-characterised to allow scientific analyses which are presented in an accompanying series
of early papers. At this stage, HFI data appears to be of high quality and we expect that with further refinements of the data processing we should
be able to achieve, or exceed, the science goals of the Planck project
Stratabound arsenic and vein antimony mineralisation in Silurian greywackes at Glendinning, south Scotland
Stratiform and disseminated pyrite-arsenopyrite
concentrations are overprinted by fracturecontrolled
polymetallic mineralisation including
stibnite through at least tens of metres of Silurian
sediments at Glendinning, near Langholm. Three
shallow boreholes were drilled on an anomaly
defined by VLF-EM and II? surveys and by
antimony values X0 ppm in thin B-C horizon
soils. A parallel conductive zone with an
accompanying soil anomaly but lacking an IP
response was investigated by a fourth hole. The
stratabound sulphides form disseminations and
bands parallel to the bedding and are particularly
concentrated in intraformational breccia units
regarded as debris flows, which, together with the
presence of smaIl scale slump folds in the greywackes,
testify to the existence of an unstable
slope during sedimentation. The thickest such
unit has a true thickness of 4 m and together with
8 m of adjoining greywackes grades 0.7% As.
Phases of fracture-controlled Fe-As-Sb-Pb-
Zn-Cu-(?)Hg mineralisation associated with widespread
dolomite and quartz veinlets and narrow
breccia veins are superimposed on the stratabound
mineralisation. Their spatial association with the
stratabound mineralisation, the presence of up to
0.33% Sb in the stratiform arsenopyrite and as
much as 5% As in the stratiform pyrite, favour a
common source for the arsenic and antimony. This
source was probably a synsedimentary metal
accumulation in a mid or lower fan environment
where euxinic conditions periodically developed