Carved Surfaces Research Articles

Preparation of Tung Oil-Modified Raw Lacquer Films and Application for Mechanical Carving Technique

Raw lacquer, known for its superior performance as a natural liquid coating, boasts excellent physical and mechanical properties as well as durability, making it widely used in manufacturing. However, the high hardness of the lacquer film upon complete curing poses challenges for carving and mechanical engraving. Therefore, it is necessary to study the curing process of lacquer films to obtain films suitable for carving or mechanical engraving. This study involves the preparation of raw lacquer with varying amounts of tung oil added, followed by the measurement of film drying time, surface roughness, glossiness, hardness, and adhesion on substrates to determine the optimal drying conditions. Additionally, SEM analysis of the carved surfaces and FT-IR analysis were used to investigate the impact of tung oil addition on lacquer carving performance and its variation. The results indicate that tung oil, to a certain extent, contributes to a smoother lacquer film but adversely affects film hardness and adhesion to Prunus serotina. However, with an increase in the amount of refined tung oil to 15%, the film exhibits improved glossiness, smoother carving tool marks, and reduced debris, thereby validating the feasibility of mechanical carving of tung oil-modified raw lacquer to some extent.

Frederick H. Evans's Lantern-Slide Lectures as a “Clock for Seeing”

In Frederick H. Evans’s Lantern-Slide Lectures as a “Clock for Seeing,” Dervla MacManus presents an indepth examination of the British photographer Frederick Henry Evans’s Lincoln Cathedral lantern-slide lecture, which he delivered three times—in 1896, 1899, and 1902. Although better known for his platinotype photography, Evans also created series of lantern slides that represent prolonged encounters with buildings played out in sequences of images. Recalling Roland Barthes’s description of the photograph as a “temporal hallucination,” MacManus identifies and explores the spatial and temporal hallucinations evoked by Evans’s Lincoln Cathedral lecture. She argues that the temporal character of the lecture was a complex constellation driven by the built fabric of the cathedral itself, moving back and forth between past and present, and in turn giving rise to a spatial ordering of time. This analysis highlights the significant role played by optical technologies in Evans’s creation of a spatially and temporally idealized version of the cathedral. Further, it shows how Evans’s encounter with the building, mediated by the camera lens, encouraged a shift in photographic modes—from a spatial mode intended to re-create architectural experience to a scopic mode that scrutinized the cathedral’s richly carved surfaces.

Additional geometric investigation of carved Monge surfaces

The large number of scientific papers on carved Monge surfaces give an idea of the dynamism of the research activity on them. Based on a definition of the concerned surfaces, several investigations have been carried out and many scientific works produced. The methods used by scientists to investigate the geometry of these surfaces are those of the differential geometry. Additional investigations, by mean of the kinematic method gave as a result, an alternative definition: a carved surface is generated by the motion of some plane curve (generatrix) along another arbitrary curve (directrix) so that the generatrix curve lies in the normal plane of the directrix line and is rigidly connected with it. However, it should be noted that the latter condition is necessary, but not sufficient for the formation of a carved surface. To achieve this goal, methods of differential geometry are used. In this article, the equation of the generatrix curve in the polar coordinate system is used and the parametric equation of carved Monge surfaces is specified that allows to more study their inner and outer geometries. New equations are obtained for more kinds of carved Monge surfaces that are classified and plotted by mean of the software Mathcad. These new forms of carved Monge surfaces can be used as middle surfaces for thin elastic shells that will be expressive and cover large spans.

Efficacy of laser cleaning in the removal of biological patina on the volcanic scoria of the rock-hewn churches of Lalibela, Ethiopia

The Lalibela rock-hewn churches are one of the most important religious pilgrimage sites in Ethiopia. These churches are carved from the scoriaceous basalt rock substrate, which has been exposed to attack by biological agents with significant loss of surface material. Particularly, the widespread growth of lichens and other microorganisms on the carved surfaces of the churches has proven to represent a substantial threat for the preservation of the site. In this study, laboratory tests have been conducted to assess the feasibility of using laser technology as an efficient cleaning method of biological patina from polymineralic stone substrates. Multi-analytical techniques were applied for the characterization of the stone samples collected from two of the Lalibela churches: Bete Giyorgis and Bete Amanuel. Stone samples artificially inoculated with bacteria, yeast, fungi isolates, and lichen-encrusted samples were laser cleaned using UV and IR laser wavelengths. The high content of Fe and Ti oxides and the high porosity have made the stone surfaces easily susceptible to low-energy laser treatment. Results indicate that laser cleaning can be applied to polymineralic lithotypes and UV irradiation can successfully remove lichen colonies. Further studies need to be conducted to optimize the laser procedure in polymineralic, high porosity stones.

Consolidation of a sepiolite-rich sandstone—learning from failure

Attempts to consolidate an armorial panel from Elgin Cathedral with a solution of Paraloid B72 in acetone had an unexpected adverse reaction and led to irreversible surface damage. XRD analysis identified unusual near-surface pockets of sepiolite below the affected areas. While not identified as expansive by XRD, sepiolite powder visibly increased in volume when submerged in acetone. Solvents with a lower polarity index were investigated and the addition of toluene did not appear to impact on sepiolite powder. Following successful treatment tests, Paraloid B72 solutions in toluene were used to consolidate and restore the carved surface of the armorial panel. Unusual treatment failures, as in this case, present learning opportunities and sharing such experiences honestly may inform colleagues in similar situations.

Archaeological Evidence for Modern Coastal Uplift at Diu, Saurashtra Peninsula, India

There is a tank hewn into coastal Pleistocene limestone near Diu city on the Saurashtra Peninsula of western India. Site survey and a review of similar structures worldwide provide evidence that this tank could have been used for holding fish or Murex snails. The approximately 5 × 5 m tank is connected to the sea by a 1‐m‐deep canal; today it would be impossible to use the tank, given that not even the high spring tides can fill it. It is suggested that the Diu coast was uplifted by ∼0.5 m after the tank was hewn in the coastal platform. Since that time, the carved surfaces have been modified by coastal karst dissolution and have developed deep gouge marks. Uplift of the Diu coast raises the possibility of a major seismic event in Diu during the latter part of the last millennium.

3D-laser scanning of the Parthenon west frieze blocks and their digital assembly based on extracted characteristic geometrical details

The stereo geometry and the colors of the Parthenon west frieze carved blocks exhibited in the Acropolis Museum of Athens (AMA) were captured by laser scanning. Considering the large size and weight of the frieze blocks fixed in permanent positions, a portable laser scanner supported by convenient software was used. This technique is flexible in facing shadowing effects, reaching the back sides of folded superficial features and assessing immediately the recorded data. Taking into account the elevated requirements for scanning accuracy and the blocks' large size, each relief was digitized in successive individual subareas. Via processing of the obtained numerical results, the assembly of the subareas in a universal carved surface was performed as well as a digital mapping of the exact west freeze blocks' three dimensional geometry. A comprehensive evaluation of the obtained numerical data revealed characteristic geometrical features, a common inclination for the background level of all reliefs and a slight trapezoidal front view of certain frieze blocks. The pleural slopes of these blocks were analytically determined taking into account zero seams' thickness between adjacent blocks. The calculated results converged with the attained ones by the evaluation of the numerical data of the scanned surfaces. The latter data were obtained for the first time at such a high accuracy level. Based on these results, procedures employed for assembling the Parthenon west frieze from antiquity were documented with evidences. Furthermore, the digital geometry of the blocks was imported into a virtual environment where their mounting onto the sloped architraves was simulated, thus allowing the reconstruction of the initial west frieze arrangement. The inclinations of the epistyles were determined considering published results concerning the vertical curvature of the Parthenon opisthonaos' stylobate. The vertical curvature of the simulated west frieze arrangement converges sufficiently with that of the original blocks exhibited in AMA. Since the Parthenon west frieze has been dispersed and therefore cannot be observed in its entirety as built in antiquity, the paper enables scholars, architects and art historians to consider it as a complete artifact.

A media luz. Grabados de la Prehistoria Reciente en abrigos galaicos

The systematic survey of rock art in the area of the town council of Porto do Son (A Coruna) has allowed us to find nearly two hundred carved surfaces, two of them located within rock shelters. Two other examples in the Western regions of Galicia must be added to those. The motifs inside the rock shelters are exactly the same as those found in the open-air petroglyphs, which can be roughly dated to the third millennium BC. These finds attest to the existence of an intentional constraint on the visibility of these graphic manifestations. The coexistence of motifs inside cavities and others located outdoors, even on fairly conspicuous vertical friezes, shows the variability of this phenomenon and allows us to reflect on the different audiences at which the rock sites would have been aimed.

Wells Cathedral: Conservation of Figure Sculpture 1977–1986

The present article is a critical review of the decision process and conservation measures at Wells Cathedral in Wells, Somerset, England over a period of approximately 14 years. Conservation of figure sculptures on the West Front of Wells Cathedral was undertaken without adequate prior study and without provision for training conservators. Early experiments with limewater for stone hardening predisposed the architect, A. D. R. Caroe, and his Clerk of Works to the methods developed by Eve and Robert Baker. An advisory committee was appointed; however, the decision to appoint Robert Baker as Consultant Conservator was taken by Caroe. Baker resigned midway through the work, after which the training and supervision of conservators was limited. The campaign (1977–1986) resulted in lime mortar repairs to figures that improved their capacity for survival; however, the excessive use of water resulted in dissolving the sulphate crusts that replicated the original carved surfaces.

Boulder accumulations produced by the 20th of February, 1743 tsunami along the coast of southeastern Salento (Apulia region, Italy)

The detachment of large boulders in the nearshore zone and their deposition farther inland are the main morphological effects of tsunamis on rocky coasts. Along the Otranto–Leuca coast (southeastern Apulia, Italy), two boulder accumulations have been recognized and studied. At the Torre Sasso locality, boulders weighing up to 31 t are scattered from sea level to about 5 m of elevation and clustered in groups of several imbricated elements. At Torre S. Emiliano an impressive accumulation made of large boulders has been recognized and studied. The accumulation is about 30 m wide and follows the present coastline for about 2.5 km at a variable distance of 15 to 40 m. Looking closer, it is compounded by two ridges. The ridge closer to the coastline shows a very steep slope seaward made of very large boulders emplaced in a vertical position; its top reaches about 11 m above m.s.l. The inner belt is lower than the outer one and consists of smaller boulders; it partly covers a 2 m thick colluvial deposit made of reddish sands. Huge blocks, weighing up to 70 t, cover the carved surface stretching from the coastline to the front of the first ridge. Analysis of the imbrication axes indicates that the catastrophic waves responsible for the development of the boulder accumulations most likely propagated from SSE to NNW direction. Karstic features occurring on the surface of the innermost boulders indicate a very recent age for their deposition as no differences have been found between the aerial-exposed surface and the soil-covered one. Three AMS radiocarbon age determinations performed on marine shells found landward the boulders have accumulated recently, i.e. within the last three centuries. Moreover, archeological remains in the top layers of the colluvial deposits covered by the boulders can be referenced to 16th–17th centuries. This evidence suggests that the 20th of February, 1743 earthquake was responsible for the generation of two large tsunami waves which caused the boulder accumulations to deposit. This earthquake was particularly violent in the Salento region where it reached grade IX on the MCS scale. Interestingly, chronicles of this event record a withdrawal of the sea in the Brindisi harbour, north of the study area. This study highlights the tsunamigenic potential offshore the southeastern Salento coast requiring that further strategies be devoted to mitigate the tsunami risk.

Biodeterioration of calcareous and granitic building stones in urban environments

Abstract Scanning electron microscopy in secondary (SEM) and back-scattered (BSEM) mode associated with energy-dispersive X-ray spectroscopy has been used to investigate decay features associated with biological colonization of calcareous and granitic building stones in monuments and rock outcrops in the UK, Portugal and Spain. In combination with physical decay caused by lichen hyphae penetrating the stone substrate, this study reveals how chemical attack by organic acid exudates derived from metabolic activity of lichens and leading to the crystallization and growth of inorganic salt compounds within the stone microfabric is contributing to the destruction and weakening of the building stone surface. BSEM analysis is particularly useful in showing extensive dissolution and corrosion of mineral surfaces underneath biological patinas. Both Ca-sulphate (gypsum) and Ca-oxalate (weddellite) precipitates are clearly associated with the presence of fungal hyphae and bacterial activity particularly in the case of calcareous building stones; the Ca-oxalates present in the example examined are then the result of biomineralization processes and do not derive from past restoration treatments or from air pollution as suggested by many authors. In urban locations, lichenous cover may facilitate the deposition of particulate airborne pollutants on the stone surface. Biological patinas are by no means forming a protective layer on the biocolonized substrate; as is the case with sulphate or non-sulphate soiling patinas from urban air pollution, they act as localized sites of intense desegregation of the stone underneath. Their promot (but careful) removal and a biocidal treatment of the infested sites in the building is then suggested to avoid permanent loss of detail, particularly harmful in the case of carved surfaces.

Normal incidence sound absorption coefficient measurement using sound intensity technique: An accuracy investigation

Sound absorption data are required in specifying and proposing the correct materials for room acoustic treatment. However, there are instances where noncommon materials such as direct piercing carved wood panels (dpcwps) are used without sound absorption data. Sound absorption measurements obtained using an impedance tube and reverberation chamber are not accurate for dpcwp. This is primarily because the wall backing the dpcwp during the measurements constitutes the carved surface, which does not exist in actual installation. Therefore, an alternative measurement technique using a sound intensity measurement technique is more appropriate for dpcwp. This paper focuses on experimental methodology where various aspects need to be taken into consideration to achieve accurate results. Various criteria affecting measurement instruments’ capabilities and other factors affecting sound intensity measurement accuracy will be discussed. Sound absorption measurement was conducted on three different perforation panels which resemble dpcwp and it was found that the sound absorption measured with a deviation from an average value of −5.59% to 5.95% can be achieved, and is particularly accurate.

Observation of a Polystyrene Surface Modified by Ultrasonic Scratching Using Atomic Force Microscopy

Polymeric materials exhibit complicated microwear properties due to their viscoelasticity. Projections are formed on a polymer surface when scratched with the tip of an atomic force microscope. Ultrasonic scratching which can be realized with the combination of an atomic force microscope and a quartz crystal resonator have been applied for a polystyrene surface for modification without projection formation. The polystyrene surface oscillated laterally by the quartz crystal resonator is scan-scratched with a diamond tip for a progressive cutting force. Scratching parallel to the direction of the surface oscillation is the most effective for cutting the polystyrene surface. No projections are observed on the flat carved surface by ultrasonic scratching. With respect to the local elastic properties, although areas scratched without surface oscillation exhibit increased elasticity at the projections, ultrasonically scratched areas exhibit no change in elasticity. Furthermore, on an area previously modified by ultrasonic scratching, projections are not produced by scratching without surface oscillation.

The Statue-Column of a Queen from Saint-Thibaut, Provins, in the Glencairn Museum

This study establishes the history of the statue-column of a queen in the Glencairn Museum from the time it was salvaged from the debris of the destroyed church of Saint-Thibaut in Provins until purchased by the late Raymond Pitcairn in 1923 for his private collection. The results of an archeological examination of the statue are presented with supplementary diagrams. The examination revealed that the facial animation called "the smile of Provins" did not result from the commercial restoration that immediately preceded the sale, but was an original and precocious feature, and that the retouching of the carved surfaces was mostly cosmetic and quite minor. The major modification involved the back of the statue where the figure proper was cut away to extend the column the full length of the figure. A regional idiosyncrasy, the column had originally backed only the head and neck and did not extend below the shoulders. The hemline, feet, and socle of the queen had been cut off before 1822. Accepting the hypothesis that the statue-column represents Sheba, the essay proposes that the cropped portion may have contained the attribute of a goose's foot--an iconographical type for Sheba known in the region surrounding Provins. Although no proof survives to verify that the statue was "la reine pédauque," the hypothesis offers an explanation for the deliberate cropping that otherwise seems inexplicable. Finally, by evaluating all available evidence, the study gives a sharper focus to the dating of the statue and places it ca. 1160, among the first generation of portal figures following in the Chartrain tradition. The high quality of the carving and elegance of detail make the queen a worthy successor to the statues by the Chartres head master.

Microstructure of amalgam surfaces

The polished amalgam surface was smoother than the burnished and the carved surfaces. The burnished surface was smoother than the carved surface. The granular structures on the burnished amalgam surface were found to be of tin-mercury alloy. Polishing appears to be the best finishing technique for amalgam restorations, and there is no substitute for it.

Surface roughness of amalgam fillings made by various technics.

Various concepts concerning finishing and polishing of amalgam have been reported. The effect of smooth polishing of amalgam immediately after insertion was considered to be lost by crystal grain growth with setting reaction. Consequently, many investigators have recommended that the amalgam be finished and polished at least 24 hours after insertion.2 Burnishing immediately after insertion was a common technic for amalgam fillings. This technic was recently prohibited by many investigators, however, because they believe that the burnishing collects excess mercury to the filling margins and lowers the physical and chemical properties.3 5 Polishing the proximal surfaces that set against matrix bands is quite complicated, however, and many dentists believe that the surfaces are usually smooth enough and polishing is unnecessary. These opinions are mostly conjecture and lack direct experimental confirmations, so the present study was undertaken to compare the roughness of carved surfaces, burnished surfaces, surfaces that set against matrix bands, finished surfaces, and polished surfaces of amalgam fillings.