Tenths Of Millimetre Research Articles

3D DIGITIZATION OF AN HERITAGE MASTERPIECE - A CRITICAL ANALYSIS ON QUALITY ASSESSMENT

Despite being perceived as interchangeable when properly applied, close-range photogrammetry and range imaging have both their pros and limitations that can be overcome using suitable procedures. Even if the two techniques have been frequently cross-compared, critical analysis discussing all sub-phases of a complex digitization project are quite rare. Comparisons taking into account the digitization of a cultural masterpiece, such as the Etruscan Sarcophagus of the Spouses (Figure 1) discussed in this paper, are even less common. The final 3D model of the Sarcophagus shows impressive spatial and texture resolution, in the order of tenths of millimetre for both digitization techniques, making it a large 3D digital model even though the physical size of the artwork is quite limited. The paper presents the survey of the Sarcophagus, a late 6th century BC Etruscan anthropoid Sarcophagus. Photogrammetry and laser scanning were used for its 3D digitization in two different times only few days apart from each other. The very short time available for the digitization was a crucial constraint for the surveying operations (due to constraints imposed us by the museum curators). Despite very high-resolution and detailed 3D models have been produced, a metric comparison between the two models shows intrinsic limitations of each technique that should be overcome through suitable onsite metric verification procedures as well as a proper processing workflow.

3D DIGITIZATION OF AN HERITAGE MASTERPIECE - A CRITICAL ANALYSIS ON QUALITY ASSESSMENT

Abstract. Despite being perceived as interchangeable when properly applied, close-range photogrammetry and range imaging have both their pros and limitations that can be overcome using suitable procedures. Even if the two techniques have been frequently cross-compared, critical analysis discussing all sub-phases of a complex digitization project are quite rare. Comparisons taking into account the digitization of a cultural masterpiece, such as the Etruscan Sarcophagus of the Spouses (Figure 1) discussed in this paper, are even less common. The final 3D model of the Sarcophagus shows impressive spatial and texture resolution, in the order of tenths of millimetre for both digitization techniques, making it a large 3D digital model even though the physical size of the artwork is quite limited. The paper presents the survey of the Sarcophagus, a late 6th century BC Etruscan anthropoid Sarcophagus. Photogrammetry and laser scanning were used for its 3D digitization in two different times only few days apart from each other. The very short time available for the digitization was a crucial constraint for the surveying operations (due to constraints imposed us by the museum curators). Despite very high-resolution and detailed 3D models have been produced, a metric comparison between the two models shows intrinsic limitations of each technique that should be overcome through suitable onsite metric verification procedures as well as a proper processing workflow.

PHOTOGRAMMETRIC TECHNIQUES FOR ROAD SURFACE ANALYSIS

The quality and condition of a road surface is of great importance for convenience and safety of driving. So the investigations of the behaviour of road materials in laboratory conditions and monitoring of existing roads are widely fulfilled for controlling a geometric parameters and detecting defects in the road surface. Photogrammetry as accurate non-contact measuring method provides powerful means for solving different tasks in road surface reconstruction and analysis. The range of dimensions concerned in road surface analysis can have great variation from tenths of millimetre to hundreds meters and more. So a set of techniques is needed to meet all requirements of road parameters estimation. Two photogrammetric techniques for road surface analysis are presented: for accurate measuring of road pavement and for road surface reconstruction based on imagery obtained from unmanned aerial vehicle. The first technique uses photogrammetric system based on structured light for fast and accurate surface 3D reconstruction and it allows analysing the characteristics of road texture and monitoring the pavement behaviour. The second technique provides dense 3D model road suitable for road macro parameters estimation.

PHOTOGRAMMETRIC TECHNIQUES FOR ROAD SURFACE ANALYSIS

Abstract. The quality and condition of a road surface is of great importance for convenience and safety of driving. So the investigations of the behaviour of road materials in laboratory conditions and monitoring of existing roads are widely fulfilled for controlling a geometric parameters and detecting defects in the road surface. Photogrammetry as accurate non-contact measuring method provides powerful means for solving different tasks in road surface reconstruction and analysis. The range of dimensions concerned in road surface analysis can have great variation from tenths of millimetre to hundreds meters and more. So a set of techniques is needed to meet all requirements of road parameters estimation. Two photogrammetric techniques for road surface analysis are presented: for accurate measuring of road pavement and for road surface reconstruction based on imagery obtained from unmanned aerial vehicle. The first technique uses photogrammetric system based on structured light for fast and accurate surface 3D reconstruction and it allows analysing the characteristics of road texture and monitoring the pavement behaviour. The second technique provides dense 3D model road suitable for road macro parameters estimation.

Chapter 3 Active tectonics in the central and eastern Azores islands along the Eurasia–Nubia boundary: a review

Abstract The geodynamic setting of the Azores archipelago, straddling the triple junction between the North America, Eurasia and Nubia plates, is reflected in frequent volcanic and tectonic activity. A review of neotectonics is presented for the islands forming the central and eastern groups of the Azores (Faial, Pico, São Jorge, Graciosa, Terceira, São Miguel and Santa Maria). The geometry and kinematics of active faults displacing stratigraphic and geomorphological markers of Pleistocene and Holocene age are presented. Slip-rates were determined using the available ages for the displaced markers. Maximum expected moment magnitudes were estimated using empirical correlations between magnitude and fault length, fault area and maximum observed surface displacement during surface-rupturing palaeoearthquakes. Neotectonic parameters show that the faults are in most cases very to moderately active, with slip-rates usually ranging from a few tenths of millimetres to a few millimetres per year, while maximum expected magnitudes vary from M w 6 to 7. These magnitudes are in agreement with the instrumental and historical seismic record in the region. Neotectonic data define a dextral transtensive stress regime acting on the region and contribute to characterizing the complexity of the geodynamic processes that dominate the western-most segment of the Eurasia–Nubia plate boundary.

Prognostic value of the circumferential resection margin after neoadjuvant treatment in esophageal cancer patients.

147 Background: Involvement of the circumferential margin (CRM) is an important factor in esophageal cancer (EC) patients. CRM definitions are commonly based on the College of American Pathologists (CAP) at 0 mm and the Royal College of Pathologists (RCP) at >1 mm. We evaluated which CRM definition is useful in current practice with neoadjuvant chemoradiotherapy (CRT) and whether the CRM cut-off value differs after CRT. Methods: We prospectively included 209 patients (104 with CRT) with locally advanced EC (stage II-III), who underwent radical transthoracic esophagectomy. Patients were followed for at least 2 years after surgery or until death. Patients with <1 mm longitudinal resection margins were excluded. Cancer related death was scored as event and death of other causes as end of follow-up (median 27: IQR 14.0 - 42.8 months). CRMs were measured in tenths of millimetres by experienced pathologists. Pathologic proven tumor regrowth, unequivocal radiologic suspicion or obvious clinical manifestations were marked as recurrence. Prognostic factors with a P<0.1 in univariate analyses were incorporated in multivariate Cox-regression analyses in which both CRM definitions were assessed separately. In an explorative analyses the CRM cut-off values in the surgery-only and CRT group for 2-year disease free survival (DFS) was assessed using CRM between 0-1.5 mm in the Cox-regression model. Results: Independent prognostic factors for 2-year DFS (P<0.05) in the study group were: tumor length (>5cm), >0.2 L/N+ ratio, angioinvasion and CAP R0. In the surgery group; tumor length, >4 N+, angioinvasion and CAP R0 were independent prognostic factors (P <0.05). In the CRT group only pN stage (P<0.01) was independent prognostic for 2-year DFS. The CRM cut-off value was significant at 0.2-0.3 mm for the surgery and CRT group, respectively. Conclusions: The CAP value was only independent prognostic for 2-year DFS in the surgery group. The CRM cut-off value was significant at 0.2 and 0.3 mm in the surgery and CRT group, respectively.

Abandoned Remšnik mine with ramsbeckite and namuwite(?)

The polymetallic Remšnik ore deposit is situated at the Kobansko area in northern Slovenia. Mineralization occurs in the thrust zone of the weakly metamorphosed old Palaeozoic rocks of the Magdalensberg formation, the Remšnik nappe, onto the retrogressed schists of the Austroalpine metamorphic basement. Hydrothermal ore mineralization and silicification follow slaty cleavage in partly brecciated marmorized dolomite lenses and subordinately in metatuffites and phyllites. Its origin is most probably connected to the lively Tertiary magmatism, occurring at the Pohorje Mountains. Mineral paragenesis of the predominant Pb, Cu and Zn silver bearing sulphide ore is associated with numerous secondary minerals. Among them, two rare sulphates with H2O of Cu and Zn occur, found for the first time in Slovenia. The green, transparent monoclinic crystals, only some tenth of millimetre in size were determined by SEM as ramsbeckite (Cu, Zn)15(SO4)4(OH)22 ∙ 6(H2O). Greenish in colour are also leafy, hexagonal, flowery intergrown crystals, which most probably belong to namuwite (Cu, Zn)4(SO4)(OH)6 ∙ 4(H2O). Its submicroscopic size and small quantity did not permit reliable determination, yet.

Prediction of hardness–depth profile from indentations at surface of materials

Surface treatments are used to increase the resistance of the surface of mechanical parts. Unlike thin films, surface hardened materials may cover several tenths of millimetres in depth. The effectiveness of such treatments is studied by analysing the hardness–depth profile. In this paper, the authors describe a method to evaluate the hardness profile with depth based on the estimation of the contribution of deeper zones of the hardened material to the hardness of the surface through the practice of a series of indentations on the surface with increasing loads. This model allows estimating the hardness of virtual layers through a step by step calculation process at increasing depths under the surface of the material. The model was satisfactorily tested on stainless steel previously surface treated through ion nitriding with a duplex process consisting in ion nitriding followed by the irradiation with high energy short duration plasma beams of argon.

Neotectonic development of drainage networks in the East Sudeten Mountains and monitoring of recent fault displacements (Czech Republic)

This paper presents results of morphotectonic research carried out in order to determine the neotectonic development of the drainage network in the NE spur of the Bohemian Massif (central Europe). The area studied comprises the north-eastern sector of the Rychlebské Mts, belonging to the Sudeten Mountains and the adjacent part of the Žulovská Hilly Land in the Sudetic Foreland (Czech Republic). Analysis of drainage network characteristics such as cross-sections, erosion rate, longitudinal river profiles, stream length-gradient index (SL) and investigation of alluvial fans/terraces was performed using detailed geomorphological mapping and field examination, and DEM data. Moreover, a reconstructed neotectonic evolution was compared with present-day fault movements obtained by fault monitoring using the TM71 deformeter. The deformeter was installed directly across faults in two karst caves in the study area within the NW–SE striking Sudetic Marginal Fault (SMF) zone. This zone is one of the morphologically most prominent neotectonic structures in central Europe, separating the Sudeten Mountains from the Sudetic Foreland. Morphotectonic research reveals that segments of enhanced erosion correspond well with increased SL indices, changes in valley cross-sections and anomalies in the longitudinal profiles. The beginnings of the stretches of increased headward erosion/rejuvenated erosional phase are concentrated at the foot of marginal slopes of the mountainous sector of the study area, which supports the hypothesis that uplift of the mountainous sector is still expressed in its relief. Alluvial fans/terraces of three levels recognized in the adjacent Žulovská Hilly Land are of Middle to Late Pleistocene age: Saalian 1 (240–280 ka), Saalian 2 (130–180 ka) and Weichselian (10–80 ka), respectively. They postdate the retreat of the last continental ice-sheet, which reached the study area in Elsterian 2 (400–460 ka). Their relative heights above the river channel are greater than terrace levels of the same age along the main Nysa Kłodzka River. The height differences attain 20 m at the highest level 1, at least 8 m at level 2, and up to 2–3 m at level 3. These discrepancies imply post-Saalian 1 uplift of the Žulovská Hilly Land relative to the topographically lower Nysa Kłodzka valley. Monitoring of present-day tectonic movements in the studied area revealed slow micro-displacements (hundredths to tenths of millimetres per year). The displacements have an aseismic character and the vertical component always prevails over the horizontal one. The inferred compressive stress comes generally from the southern sector, which would imply dextral transpression in the studied portion of the SMF, where the northern part is thrusting over the southern one. The trend of these present-day movements corresponds well with uplift of the studied area north of the SMF, which is also indicated by analysis of the drainage network. It is concluded that in areas of low tectonic activity the detailed study of individual characteristics of the drainage network, particularly their spatial relationships, as well as monitoring of fault micro-displacements can reveal rates and kinematics of ongoing tectonism.

Polymer Bonded Anisotropic Thick Hard Films for Micromotors/Microgenerators

Hard magnetic films are very promising elements for the production of MEMS, due to the optimum scaling properties of magnetic interactions. These elements are specially well suited for the development of micromotors and microgenerators. A magnetization multipolar structure is required on the material to be used in such applications. In order to generate this multipolar structure, a well defined magnetic anisotropy is required, this anisotropy being directed in many cases in the direction perpendicular to the film plane. The maximum torque obtainable from a micromotor depends mainly on the mass of magnetic material (i.e. the film thickness). Anisotropic hard magnetic films with thicknesses on the order of tenths of millimetres can not be prepared by any of the common thin film deposition techniques available nowadays. Though some preparation techniques have been developed that can be used to prepare hard magnetic films with the desired thicknesses, they are not able to produce materials with a well defined anisotropy along the direction perpendicular to the film plane. In this work, we describe a method to prepare anisotropic hard magnetic films with thicknesses of tenths of millimetres by dispersing NdFeB anisotropic microparticles on a polymethyl methacrylate (PMMA) solution at room temperature under low intensity magnetic fields. Large macrospic anisotropics have been reached for magnetic fields as low as 150 Oe applied during the deposition, with room temperature coercivities in excess of 1.2 T and maximum energy products up to 9 MGOe. The analysis of the temperature dependence of the magnetic properties indicates that a columnar arrangement of the particles on the direction parallel to the field applied during the preparation is the reason of the observed macroscopic anisotropy. The films can be easily deposited onto different substrates and mechanised in order to obtain a smooth surface with the desired shape. Their use in micromotors/microgenerators has been tested.

Quality control by autoradiography for the thin layer activation technique

In measurements of wearing and corrosion based on the thin layer activation technique; a part is locally activated by charged particles and placed in its working context and wear/corrosion is calculated precisely and continuously by measuring the removed activity. It is essential in the method to know the exact position of the activated zone because the wearing ratio may vary up to 50% for a shift of only 2 mm. So we do need a control procedure after irradiation. Our quality control system of irradiated parts is based on autoradiography. The films are chosen according to the type of emission of the source: high resolution films as Structurix D4 are used with beta sources whereas pure gamma sources need more sensitive films as Structurix D7 with lead filters. The finite range of the rays generates blur which can be partly corrected by digitizing and deconvoluting the image using IRIS software. The exposure time is empirically determined for each radioisotope and linked to the activity, in order to optimise contrast and resolution. The position control is mainly based on a system of detailed marks and cuts made under inactinic light; we can obtain a basic precision of approximately one tenth of millimetre. Routine applications of this control methodology confirm its simplicity, precision, speed and its relative low cost.

Hydraulic architecture and water flow in growing grass tillers (Festuca arundinacea Schreb.)

ABSTRACTThe water relations and hydraulic architecture of growing grass tillers (Festuca arundinacea Schreb.) are reported. Evaporative flux density, E (mmol s−1 m−2), of individual leaf blades was measured gravimetrically by covering or excision of entire leaf blades. Values of E were similar for mature and elongating leaf blades, averaging 2·4 mmol s−1 m−2. Measured axial hydraulic conductivity, Kh (mmol s−1 mm MPa−1), of excised leaf segments was three times lower than theoretical hydraulic conductivity (Kt) calculated using the Poiseuille equation and measurements of vessel number and diameter. Kt was corrected (Kt*) to account for the discrepancy between Kh and Kt and for immature xylem in the basal expanding region of elongating leaves. From base to tip of mature leaves the pattern of Kt* was bell‐shaped with a maximum near the sheath–blade joint (≈ 19 mmol s−1 mm MPa−1). In elongating leaves, immature xylem in the basal growing region led to a much lower Kt*. As the first metaxylem matured, Kt* increased by 10‐fold. The hydraulic conductances of the whole root system, (mmol s−1 MPa−1) and leaf blades, (mmol s−1 MPa−1) were measured by a vacuum induced water flow technique. and were linearly related to the leaf area downstream. Approximately 65% of the resistance to water flow within the plant resided in the leaf blade. An electric‐analogue computer model was used to calculate the leaf blade area‐specific radial hydraulic conductivity, (mmol s−1 m−2 MPa−1), using , Kt* and water flux values. values decreased with leaf age, from 21·2 mmol s−1 m−2 MPa−1 in rapidly elongating leaf to 7·2 mmol s−1 m−2 MPa−1 in mature leaf. Comparison of and values showed that ≈ 90% of the resistance to water flow within the blades resided in the liquid extra‐vascular path. The same algorithm was then used to compute the xylem and extravascular water potential drop along the liquid water path in the plant under steady state conditions. Predicted and measured water potentials matched well. The hydraulic design of the mature leaf resulted in low and quite constant xylem water potential gradient (≈ 0·3 MPa m−1) throughout the plant. Much of the water potential drop within mature leaves occurred within a tenth of millimetre in the blade, between the xylem vessels and the site of water evaporation within the mesophyll. In elongating leaves, the low Kt* in the basal growth zone dramatically increased the local xylem water potential gradient (≈ 2·0 MPa m−1) there. In the leaf elongation zone the growth‐induced water potential difference was ≈ 0·2 MPa.

Current transfer lengths and the origin of linear components in the voltage - current curves of Ag-sheathed BSCCO components

The commonly observed linear sections in the voltage - current characteristics of Ag-sheathed BSCCO-2212 and BSCCO-2223 composites were studied. One source of such characteristics is due to ohmic losses in the silver at the current feed points. Characteristic current transfer lengths are of the order of millimetres at 4.2 K and tenths of millimetres at 77 K. However, linear components can also be observed well away from current feed points. These were found to be associated with regions of locally reduced critical current, which provoke local transfer of the excess current into the Ag, thus producing local, ohmic V - I characteristics. Because of the finite current transfer length, some ohmic voltage can be detected even outside regions of reduced critical current. When the silver was removed from lower critical current regions, ohmic voltages were no longer observed, even when the critical current was severely reduced by local damage with a laser. Within the range of electric field covered by this experiment , we conclude that all ohmic voltages are produced by current flow in Ag.

Intrabasinal thrust-tectonic versus climate control on rhythmicities in the Eocene South Pyrenean Tremp-Graus foreland basin: inferences from forward modelling

Small-scale (10 m) sedimentary cycles of alternating fine-grained and coarse-grained sediments occur in 40–60-m-thick fan-delta sequences in Eocene deposits in the Tremp-Graus foreland basin. These deposits are investigated by means of numerical forward modelling of short-term (10–100 kyr scale) changes in sediment flux due to orbitally induced climate changes and related fluctuations in precipitation and vegetation (De Boer et al., 1991), and—as an alternative control—intrabasinal fault activity. We show that pulsating intrabasinal uplifting related to deep-seated thrusting may serve as an alternative to climate-induced fluctuations in sediment flux, provided that thrusting is cyclic. In the models, faulting between the source area and the site of the rhythmic succession causes temporal intrabasinal uplift, leading to contemporary erosion of the uplifted area and to a nearly instantaneous redistribution of sediment in a thin veneer across a wide area. This reduces the effect of flexural subsidence due to fault activity, so that major lateral facies shifts through time are absent, while significant changes in sediment flux do occur. The models also provide new insights into the dominant geodynamic mechanisms during deposition of the Eocene sequence. To explain the observed sediment thickness in the studied sequence, either a sea-level rise, accompanied by relatively high transportation coefficients (larger maximum erosion rates—millimetres per year), or orogenic wedge growth, accompanied by smaller transportation coefficients (lower maximum erosion rates—tenths of millimetres per year) has to be adopted. In the case of the eustasy scenario, it is predicted that the basin thins to the north. In case of the orogenic wedge growth scenario, a northward thickening of the basin fill is predicted, unless a subsurface triangular fault zone is adopted.

Spectral broadening of light scattered from polysaccharide gels

Light scattering Rayleigh linewidth measurements have been made on 0.5% calcium alginate gels using the autocorrelation method. The degree of spectral broadening has been found to be small (∼2%) although two relaxation times (∼7 and ∼50 msec) within the broadened component have been measured. The variations in the degree of spectral broadening and the relaxation times with angle of scatter were found to be much less than predicted by any existing theory, and no systematic variation in any of the parameters with temperature was detected within the range 3° to 88°C. By scanning through the gel with the focused laser beam, however, it has been shown that long range (tenths of millimetres), long term (tens of minutes), fluctuations in alginate density occur. It is possible that the observed relaxation times represent the continual rearrangements of polymer chains which, assuming a junction zone type of structure, would be necessary for these fluctuations to take place. Oscillations were generally found to be superimposed upon the autocorrelation functions and these have been positively identified with bulk oscillations of the specimen. A theory is advanced explaining why bulk oscillations manifest themselves in the autocorrelation function and predicting the marked increase in amplitude with angle of scatter observed experimentally. Experiments are also described in which the diffusion coefficients of dextran fractions and globular proteins within 0.5% gels were measured by investigating the heterodyne beat spectrum. It was found that the movement of macromolecules with 1 D 20W less than 3 × 10 4 sec/mm 2 was virtually unimpeded by the gel. Diffusion constants fell to about one third of those in aqueous solution for values of 1 D 20W ∼ 9 × 10 4 sec/ mm 2 . Thus there are large interstitial spaces within the gel and if a junction zone type of structure is correct, each junction zone must consist of an association of some hundreds of chains. Some preliminary results are presented of experiments with agarose and bovine vitreous humour.

Recent experiments with nuclear emulsions

It is unnecessary to stress the many significant contributions made during the past 20 years to nuclear and high-energy physics by means of the nuclear emulsion technique. One needs only to recall the new particles and decay modes that have been first observed with it. With the development of other powerful techniques, however, such as the spark-chamber and bubble-chamber, readily adaptable to automatic methods of analysis and data handling, nuclear emulsion has inevitably tended to fall into the position of a supplementary method. Nevertheless, there are still important experiments for which it is the most convenient, indeed in some cases the only, technique available, and this paper will discuss such experiments, either recently carried out or proposed for the future, using beams of particles from high-energy accelerators. Nuclear emulsion possesses one most significant advantage over all other tech­niques, namely, the extraordinarily high spatial resolution of which it is capable. Other techniques can resolve events separated by tenths of millimetres. Nuclear emulsion can resolve events separated by tenths of micrometres. This high spatial resolution has made possible the measurement of the lifetime of the π 0 -meson (ca.10 -16 s) and is the basis of our confidence that there are no other commonly occurring unstable particles with lifetimes in the range 10 -11 to 10 -16 s. Most of the experiments described in this paper are particularly suited to the nuclear emulsion technique because they make use of this characteristic feature.