Summary
In the last few years, the study of cut marks on bone surfaces has become fundamental for the interpretation of prehistoric butchery practices. Due to the difficulties in the correct ...identification of cut marks, many criteria for their description and classification have been suggested. Different techniques, such as three‐dimensional digital microscope (3D DM), laser scanning confocal microscopy (LSCM) and micro‐photogrammetry (M‐PG) have been recently applied to the study of cut marks. Although the 3D DM and LSCM microscopic techniques are the most commonly used for the 3D identification of cut marks, M‐PG has also proved to be very efficient and a low‐cost method. M‐PG is a noninvasive technique that allows the study of the cortical surface without any previous preparation of the samples, and that generates high‐resolution models. Despite the current application of microscopic and micro‐photogrammetric techniques to taphonomy, their reliability has never been tested. In this paper, we compare 3D DM, LSCM and M‐PG in order to assess their resolution and results. In this study, we analyse 26 experimental cut marks generated with a metal knife. The quantitative and qualitative information registered is analysed by means of standard multivariate statistics and geometric morphometrics to assess the similarities and differences obtained with the different methodologies.
Lay description
The study of anthropogenic marks on bone surfaces has become fundamental for the interpretation of archaeological sites and prehistoric butchery practices. Cut marks are one of the most common traces used in the identification of prehistoric human practices. Though theoretically cut marks are defined in classic studies as distinctive V‐shaped grooves that appear on the surface of a bone after the removal of meat with the aid of a tool, their correct identification is not easy as cut marks can be mistaken for other nonanthropogenic traces that also appear on bone surfaces. In the last few decades, many criteria for the description and classification of cut marks have been suggested. Different techniques have been recently applied to the study of cut marks but their reliability has never been tested. In this paper, we compare three techniques recently used in the virtual reconstruction and analysis of cut marks in order to assess their resolution and results. These techniques are based on the use of two microscopes – a digital and a laser one – and of a digital camera in order to create 3D models. A total of 26 experimental cut marks generated with a metal knife were analysed in this study by means of 3D modelling, multivariate statistics and a coordinate‐based methodology for the description and analysis of the form. Here we prove that the three techniques used are equally valid for the study of cut marks and, more importantly, that a noninvasive and low‐cost method based on the use of a digital camera is perfectly valid for the analyses.
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•Three-dimensional microscope is used to in situ investigate the formation process of films.•The film morphology is controlled by the formation rate of films and the release rate of ...gases.•This study sheds light on the fundamental understanding of the film formation process.
Due to the complexity and rapidity, the formation process of interfacial polymerized (IP) films is difficult to be observed. Here, a visualized technique, optical three-dimensional microscope, is used to in situ investigate the formation process of (co)polyarylate film. As the polymerization time increases, the film surface shows varied morphologies which is mainly controlled by the formation rate of cross-linked film and the release rate of mixed gases, and tri-functional acyl chloride facilitates to form a homogeneous film comparing to bi-functional acyl chloride. The addition of phase transfer catalysts (PTCs) can accelerate the diffusion of monomer, which has two opposite effects: one is increasing the releasing rate of gases, the opposite is facilitating the increase of the cross-linking degree that inhibits the gases release. Moreover, different type of PTCs affects the film morphology in a different way. This study sheds light on the fundamental understanding of the formation process of IP films.
The Tumulus of Montefortini is an Etruscan tomb located in Carmignano (Central Italy), which is believed to date from the 7th century BC. The tumulus is an oval burial mound 80 metres long and 11 ...metres high, which houses two tombs. More than 10,000 ivory fragments, that were likely part of a rich grave good, were recovered from this site. The main raw material exploited was probably the proboscidean dentine given the presence of the "Schreger lines" on the surfaces of many specimens. In this work we analyzed a sample of this archaeological assemblage using a 3D digital microscope. This noninvasive procedure allowed to investigate the main micromorphological and micromorphometrical features of the proboscidean dentine in a relatively brief time, preserving the integrity of the archaeological finds. Unexpected results regarding to the Schreger structure were obtained from this analysis. Data collected in the present work will be useful to evaluate, through further analysis of the examined sample, the accuracy and reliability of the 3D digital microscopy in the characterization of the proboscidean taxa exploited in the past.
This paper introduces a novel micro-photogrammetric application for the examination of technological traces using a portable digital microscope. The aim is to evaluate its potential, advantages, and ...level of detail within the context of traceology studies, highlighting its importance in particular for field documentation of unmovable items. The technique is non-invasive and applicable to samples that cannot be transported outside their regions/countries of origin.
Moreover, this methodological presentation aims to provide an extensive account of the utilized technology, the accessories, the possible uses and a series of experiments designed to replicate environmental and logistical conditions commonly encountered in the field.
The goal is also to compare a 3D model obtained with a portable digital microscope to one obtained with a camera equipped with a macro lens, in order to highlight the level of detail achieved in trace visualization.
The results are also expanded and discussed, including an examination of an archaeological case study. Additionally, to evaluate the validity and accuracy of the detected traces, the data obtained has been analyzed in the context of a qualitative assessment conducted using a stereomicroscope coupled with an optical fiber reflected light system.
•Micro-photogrammetry for trace analysis in the field with a digital microscope.•Non-invasive technique to create a three-dimensional representation of the trace.•Excellent results can also be obtained at distances greater than 4 cm.•This technique provides greater detail compared to macro lens photogrammetry.•The system is adaptable to different conditions so it is effective in field application.
•The study presents a novel method for assessing FCGR in planar mixed-mode loading.•Planar mixed-mode FCGR of a newly developed alloy AA-7085 has been studied.•Equivalent SIF at different crack ...lengths was determined by XFEM simulation.•Experimentally observed crack deflection was compared with different criteria.
Determining fatigue crack growth parameters under mixed-mode loading is crucial for damage tolerance design, particularly in assessing a component's residual life with defects to prevent disasters. This study introduces a novel methodology for determining fatigue crack growth rate. A digital microscope is utilized to track the fatigue crack tip with respect to local coordinate systems established on the specimen surface. A grid is drawn and subdivided into units with proposed nomenclature. Compact Tension and Shear (CTS) specimens, extracted from AA-7085 plates, undergo fatigue loading in a servo-hydraulic universal testing machine. A fixture proposed by Richard et al. induces planar mixed-mode loading cases in the specimen. During experiments, the digital microscope tracks the crack tip using grid unit corners as local origins. The local coordinates of the crack tip are transformed into the crack tip coordinates with respect to the pre-crack tip. Crack evolution data are used to determine the fatigue crack growth rate by analyzing tangents of a three-parameter fitted curve. The equivalent SIF ranges are computed at different crack lengths in an XFEM script written in Ansys. The modified Paris parameters are found and experimentally observed crack deflection angles are compared with the Maximum Tangential stress, Strain energy density, and Richard’s criterion.
The liquid-liquid transesterification is an interesting concept to investigate. This study investigated the actual events in liquid-liquid mass transfer transesterification via microscopic visual ...observations at room temperature. Our main study topic is the saponification mechanisms, in a crucial side reaction of alkali-catalyzed transesterification. Commercial RPO and high purity FAME were used as the hydrocarbon reactants with methanol and sodium methoxide as reacting alcohol and alkaline catalyst. A concave slide was used as a microreactor and another downward one was used as a cover to set up a closed system. Soap formation was investigated over the FFA range 0.02–2.0 wt%, and water contents 0.1−1 wt%. The concentration of methoxide was 2.16, 4.23 or 8.12 wt% in methanol. FFA and alkaline created a soap film barrier at the surface boundary of methanol droplet, the thicker the higher FFA content was. Water content resulted in a weaker soap film boundary. The film barrier thickened by generated glycerol from transesterification. High content of alkaline produced a high amount of soap that affected the biodiesel yield losses from both chemical and water washing. On using commercial grade RPO (0.1 wt% FFA, 0.2 wt% water), the soap content in crude biodiesel is a key factor affecting washing losses, and our suggestion is it should be below 3000 ppm.
Objectives: The use of three-dimensional monitors and digital microscopes for microsurgery is becoming prevalent and has great expectations of providing ergonomic advantages for surgeons. However, it ...remains unclear if this approach does provide ergonomic benefits, and whether transitional difficulties will be encountered when using it in place of a conventional optical microscope. Therefore, the purpose of this study was to clarify both the subjective and objective ergonomic advantages and the learning curve associated with the use of a digital microscope. Methods: Seventeen cases of head and neck reconstruction using a digital microscope were compared with those using a conventional optical microscope with respect to the time required for vascular anastomoses, microvascular complications, and ergonomics of the surgeon. The surgeons' learning curve was evaluated by comparing the time required for the transitions during the vascular anastomoses in each series. An objective ergonomics study was conducted by evaluating muscle fatigue using electromyography (EMG) during simulated vascular anastomosis. Results: The time required for vascular anastomosis transitions using a digital microscope gradually decreased in a linear fashion. In the objective study to check muscle fatigue by using EMG, a digital microscope was found to provide an ergonomic advantage for surgeons in the lower trapezius muscle part as compared to a conventional optical microscope. Conclusions: At present, a digital microscope provides modest ergonomic benefits to surgeons and requires a certain amount of time to learn.
A simple, cheap and portable spectrophotometric system is described. It is based on the use of a cheap digital microscope housed from a 3D printed device which simultaneously supports a LED as a ...light source and a flow cell. A simple electronic device to power the LED is also described using electronic smd components. Both the digital microscope and the power source required to light the LED are connected to the USB ports of a notebook in order to avoid the need of any power source to complete the portable system. This method was applied to make the determination of Fe2+ with o-phenanthroline as chromogenic reagent. The reaction provided the red complex which is used to monitor the analytical response with the digital microscope.
Portable spectrophotometric device using a digital microscope. A: digital microscope; B: 3D printed support of the digital microscope, cell and light source; C: cuvette; D: Head for LED; E: regulated voltage power supply; F: USB digital microscope connection; G: USB regulated voltage power source connection. Display omitted
•A cheap, simple and portable spectrophotometric system has been developed using a digital microscope.•Two USB ports of a laptop are used to power the microscope and the radiation source.•A simple electronic device connected to an USB port has been used to power different kind of LEDs used as radiation source.
Novel hybrid laminates consisting of carbon fiber-reinforced polymers and steel plate cold commercial (CFRP-SPCC) have been successfully manufactured and tested in the present study. Four different ...tests have been made i.e., tensile test, flexural test, double cantilever beam (DCB) or Mode I test, and end notched flexure (ENF) or Mode II test. After being tested, these samples need to be evaluated. Hence, an inappropriate evaluation step while identifying the cause of failure of the failed specimens can create a false conclusion. The present study aims to systematically evaluate the fractured specimens of CFRP-SPCC in different tests (tensile, flexural, DCB, and ENF test) using different tools, i.e., pocket camera, digital microscope, light microscope, and Scanning Electron Microscopy (SEM). The results showed, in terms of tensile, the highest strength occurred with 1475.4 MPa. In comparison, the highest flexural strength occurred with 1516.1 MPa, while DCB and ENF showed the highest values with 116.4 and 330 J/m2, respectively. Furthermore, the results showed that digital and light microscopes are satisfied to evaluate the specimen in tensile test. However, for the flexural test, ENF, and DCB test, besides the light microscope, further analysis using SEM-EDX is recommended to evaluate the specimen after failure.
