Different Types Of Stones Research Articles

Image classification via adaptive ensembles of descriptor-specific classifiers

An automated classification system usually consists of (i) a supervised learning algorithm for automatically generating classifiers from training data, and (ii) a representation scheme for converting the training objects into vectorial representations of their content. In this work, we take a detour from this tradition and present an approach to image classification based on an adaptive ensemble of classifiers, each specialized on classifying images based on a single “descriptor.” Each descriptor focuses on a different aspect, or perspective, of images; an ensemble of descriptor-specific classifiers can thus be seen as a committee of experts, each viewing the problem to be solved with a different slant, of from a different viewpoint. We test four different ways to set up such an ensemble, based on different ways of leveraging on the individual responses returned by each member of the ensemble, and on how confident these members are on their responses. We test this approach by using five different MPEG-7 descriptors on the task of assigning photographs of stone slabs to classes representing different types of stones. Our experimental results show important accuracy improvements with respect to a baseline in which a single classifier, working an all five descriptors at the same time, is employed.

Limestone on the ‘Don Pedro I’ facade in the Real Alcázar compound, Seville, Spain

Abstract This paper discusses the research conducted prior to restoring the ‘Don Pedro I’ facade on the Real Alcázar or royal palace at Seville, Spain. The different types of stone on the facade were located and characterized, and their state of decay mapped. Although other materials (brick, rendering, ceramics, marble) are present on the facade, its main elements are made from two types of limestone: palomera and tosca , each in a different state of conservation and exhibiting distinct behaviour. Colour parameters, real and bulk densities, compactness, open porosity, water saturation coefficient and total porosity were determined to characterize the two varieties. In addition, ultrasonic techniques were used to map the various levels of decay on the facade, stone by stone, for future interventions. The findings show that owing to its petrographical and petrophysical properties, palomera stone is of a lower quality than tosca stone, and has undergone more intense deterioration.

The applicability of different waste materials for the production of lightweight aggregates

The applicability of different waste materials for the production of lightweight aggregates has been studied. The following waste materials were investigated: silica sludge, superfluous clay in the quarry, waste glass, and residue from the polishing process of different types of stone. SiC and MnO(2) were selected as foaming agents. Feldspar containing minerals and scrap glass were added in order to lower the softening point of the waste materials. The granules were prepared by mixing together finely ground waste with one or both of the selected foaming agents. The granules were then fired at different temperatures above the softening point of the glassy phase within the temperature range from 1150 to 1220 degrees C, where the foaming agent degasses, and the resulting gasses remain trapped in the glassy structure. The foaming process was observed by hot-stage microscopy. The properties of the so-obtained granules, such as their apparent density and compressive strength, were determined, and their microstructures were evaluating using SEM and polarizing microscopy. With the addition to clay of polishing residue from granite-like rocks, after firing at 1220 degrees C homogeneously porous granules with a density down to 0.42 g/cm(3) were obtained, whereas with the addition to waste silica sludge of polishing residue from granite-like rocks and waste glass with a foaming agent, after firing at 1220 degrees C densities from 0.57 to 0.82 g/cm(3) were obtained.

Role of fungi in biodeterioration process of stone in historic buildings

Fungal ability in production of pigments and organic acids have crucial role in discoloration and degradation of different types of stone in cultural heritage objects. Additionally, stone objects may support novel communities of microorganisms that are active in biodeterioration process. This investigation focuses on mycological analyses of microbial biofilm from two important buildings, made of granite and sandstone, and which were heavily colonized by fungi. The 23 fungal taxa including filamentous microfungi and yeasts with specific distribution on sandstone and granite substrate were isolated. Melanized fungi from Dematiaceae (Deuteromycotina) were dominant. The identified microfungi cause discoloration, as well as mechanical exfoliation of building stone material that was analyzed through mechanical hyphae penetration and production of dark pigments and organic acids.

Bowing and expansion of natural stone panels: marble and limestone testing and assessment

Natural stone has been used as a building material for centuries. In the past, load bearing members were made of entirely of stone, but in the last 50 years new processing techniques have made the production and use of thin facade cladding a profitable venture. Unfortunately however, marble facades on buildings in Europe and elsewhere have undergone severe deterioration. The EC-financed TEAM project (2000-2005) studied the bowing observed on marble facades in both cold and warm climates. TEAM’s main objectives were to understand and explain the expansion, bowing, and strength loss mechanisms governing the decay of marble- and limestone-clad facades, and to draft new European standards to prevent the use of marble and limestone poorly suited to outdoor cladding. A survey of some 200 buildings afforded a clear picture of the geographical, geological and climatic scope of the problem. Detailed case studies of six buildings resulted in a facade assessment methodology that included a monitoring system and risk assessment. Both laboratory and field research was conducted on almost 100 different types of stone from different countries and in place in different climates. The outcome was the determination of the decay mechanisms and critical factors. Two test methods and respective precision statements, one for bowing and the other for irreversible thermal expansion in high humidity conditions, were prepared for submission to CEN TC 246.

Dual Energy CT Characterization of Urinary Calculi: Initial In Vitro and Clinical Experience

The purpose of this study is to assess the accuracy of dual energy CT (DECT) in the characterization of renal and ureteral stones. Twenty-four renal calculi of known variable composition were scanned on a dual-source CT scanner (Somatom Definition; Siemens Medical Solutions, Forchheim, Germany) in dual energy (DECT) mode. Scan parameters for DECT were: tube potentials, 80 and 140 kV; tube current, 342 and 76 mA.s; collimation, 14 x 1.2 mm2. Dual energy properties of calculi were used to differentiate between uric acid (UA) and other calculi. Differentiation was based on a 3-material decomposition implemented in the dual energy software (Syngo VA 11; Siemens Medical Solutions). Color coding was used to display different types of stones and their DECT properties were characterized with density measurements at both photon energies. Subsequently, 20 consecutive patients with known or suspected uroliths were scanned using identical scan parameters. Stone size and material were assessed in DECT and compared with the chemical analyses of stones after mechanical extraction. With DECT characterization, differentiation of UA from other calculi was possible. Additionally, differentiation between cystine and struvite stones was shown to be feasible in vitro. In the patient cohort, DECT correctly characterized 4 UA calculi, 4 mixed, multiple calcified, and 1 cystine stone. The calculi were displayed in specific colors, ie, UA stones in red and calcified stones in blue. With dual energy CT techniques, the UA, cystine, struvite, and mixed renal calculi can be differentiated from other types of stones in vitro and in vivo. This is of clinical relevance as UA uroliths may be treated pharmacologically rather than with surgical extraction or extracorporal shockwave lithotripsy.

Current opinion in urology: new insights into nephrolithiasis

Recent studies in nephrolithiasis have investigated why stones form, improvements in medical therapy, and advances in surgical therapy. We outline recent research in these areas. We describe a series of articles characterizing the histopathology of Randall's plaques and the renal papillae in patients with nephrolithiasis, detailing genetic discoveries related to uric acid stones, describing further uses of alpha-antagonists in nephrolithiasis, and reporting improvements in extracorporeal shockwave lithotripsy technique and outcomes. Characterization of the renal papillae and Randall's plaques in different types of stones may guide the urologist in treating stones and may lead to further research into how and where stones of different compositions form.

Metabolic factors in the causation of urinary tract stones in patients with enterocystoplasties

Stones are a common complication of the storage of urine in intestinal reservoirs. Previous studies have identified predisposing physical characteristics in the reservoirs. Biochemical and dietary factors have been little investigated. Fifteen patients (6 males and 9 females) who had undergone various enterocystoplasty operations and who had subsequently formed either upper or lower urinary tract stones were investigated. The programme has been previously described and included stone, blood and urine analysis and dietary review. Comparison was made with 15 age- and sex-matched idiopathic stone formers with normal bladders. Stones were infective in origin in 86% of cases, and 14% were sterile. Metabolic screen showed that 80% of enterocystoplasty patients had risk factors for at least three different types of stone. All patients had raised pH (mean 6.93) and hypocitraturia. Five had a raised alkaline phosphatase. Raised serum and urinary calcium, hyperoxaluria and hyperuricosuria were found in 33% of patients. Five had a 24-h urine volume below 1.6 l/day. All patients had a high risk index (PSF) for phosphatic stones and 12 also for calcium oxalate stones. Compared to age-and sex-matched idiopathic stone-formers, the urine had a higher pH, sodium and protein excretion and a lower calcium and citrate excretion. Although the patients were already selected as stone-formers, the data show that metabolic and dietary factors are present. They may be as important in the aetiology of the stones, as the already recognised factors of infection and poor reservoir drainage. Investigation should include such factors, the presence of which may be taken into account in a prophylactic regime.

Role of canonical biplot method in the study of building stones: an example from Spanish monumental heritage

In this work, the canonical biplot (CB) method (Vicente-Villardon, 1992; Gower and Hand, 1996) is used to determine the origin, distribution, conservation and pollution state of the different types of stones used in the construction and restoration of monuments of great historical interest. The stone materials (sandstones) used in the Cathedral of Ciudad Rodrigo (Salamanca, Spain) have been used to assess the usefulness of the method. The age of this monument (eight centuries), together with the surrounding environmental conditions, have especially contributed to the pollution of the stone masonries, in comparison to the same stones identified in the original quarries. The CB method has allowed us to: (a) identify the sandstone varieties used in the construction; (b) locate the original quarries of these sandstones; (c) locate these materials in the building, and (d) detect the pollution and deterioration affecting the stones in the monument, in comparison to the stones of the original quarries. Copyright © 2005 John Wiley & Sons, Ltd.

Urolithiasis in enterocystoplasties.

The incidence of stones in patients with enterocystoplasty is reported as 12-52.5%. Most patients will have multiple physical factors such as immobility, need for self catheterisation and poor urine drainage, so that it is not certain that an intestinal reservoir is the cause of stones on its own. There is little or no evidence that mucus is an aetiological factor. Foreign bodies in the reservoir, such as staples, increase the risk of stone formation from 13% to 43%. Stones require surgical removal. Minimally invasive techniques may be used for small stones. A low velocity disintegrator is required so that fragments are not propelled into the intestinal mucosa. Stones are infective in origin in 86% of cases, but 14% are sterile. Metabolic screen shows that 80% of patients have risk factors for at least three different types of stone. All patients have raised pH (mean 6.93) and hypocitraturia. Raised serum and urinary calcium, hyperoxaluria and hyperuricosuria are found in up to 33% of patients.

2.6-Million-year-old stone tools and associated bones from OGS-6 and OGS-7, Gona, Afar, Ethiopia.

When and how human ancestors first used tools remains unknown, despite intense research into the origins of technology. It has been hypothesized that the evolutionary roots of stone flake technology has its origin in percussive behavior. Before intentional stone flaking, hominins potentially engaged in various percussive behaviors resulting in accidental flake detachments. We refer to this scenario as the ‘by-product hypothesis.’ In this scenario, repeated detachments of sharp stone fragments eventually resulted in intentional flake production. Here, we tested the circumstances of accidental flake production as a by-product of percussive foraging in wild capuchin monkeys (Sapajus libidinosus) from Brazil, the only nonhuman primate known to habitually produce sharp-edged flakes through a percussive behavior. We conducted field experiments where we tested the potential for accidental flake production during nut cracking. We provided three different types of stone with varied material properties as anvils to assess the circumstances in which accidental production of sharp-edged flakes occurs during nut cracking. A further freehand knapping experiment, with the raw material that exhibited accidental flake detachments, allows a direct comparison of flakes that have been intentionally produced by an experienced knapper and flakes produced during nut cracking by capuchin monkeys. Our results show that raw material quality and morphology significantly affect the rate of sharp-edged flake production as well as the resulting lithic signature of this behavior. In addition, accidental flakes produced during capuchin nut cracking on highly isotropic raw material are similar in many respects to intentionally produced flakes by a human knapper. Our field experiments highlight the fact that nut-cracking behavior can lead to the unintentional production of substantial quantities of sharp-edged flakes and therefore supports the ‘by-product hypothesis’ as a potential mechanism for the emergence of hominin flake technology.

Variability of renal stone fragility in shock wave lithotripsy

ObjectivesTo measure, in an in vitro study, the number of shock waves to complete comminution for 195 human stones, representing six major stone types. Not all renal calculi are easily broken with shock wave lithotripsy. Different types of stones are thought to have characteristic fragilities, and suggestions have been made in published reports of variation in the fragility within some types of stones, but few quantitative data are available. MethodsKidney stones classified by their dominant mineral content were broken in an unmodified Dornier HM3 lithotripter or in a research lithotripter modeled after the HM3, and the number of shock waves was counted for each stone until all fragments passed through a sieve (3-mm-round or 2-mm-square holes). ResultsThe mean ± SD number of shock waves to complete comminution was 400 ± 333 per gram (n = 39) for uric acid; 965 ± 900 per gram (n = 75) for calcium oxalate monohydrate; 1134 ± 770 per gram (n = 21) for hydroxyapatite; 1138 ± 746 per gram (n = 13) for struvite; 1681 ± 1363 per gram (n = 23) for brushite; and 5937 ± 6190 per gram (n = 24) for cystine. The variation for these natural stones (83% ± 15% coefficient of variation) was greater than that for artificial (eg, gypsum-based) stones (17% ± 8%). ConclusionsThe variability in stone fragility to shock waves is large, even within groups defined by mineral composition. Thus, knowing the major composition of a stone may not allow adequate prediction of its fragility in lithotripsy treatment. The variation in stone structure could underlie the variation in stone fragility within type, but testing of this hypothesis remains to be done.

Fluorescence lidar imaging of the cathedral and baptistery of Parma

Extensive fluorescence multispectral imaging of the cathedral and baptistery of Parma, Italy, is reported and discussed. In particular, the first fluorescence imaging data from protection-treated stony materials were recorded. Fluorescence spectra were taken with a mobile lidar system scanning the monument surfaces with a frequency-tripled Nd:YAG laser beam from a distance of about 80 m. For each pixel of the area investigated, a high-spectral-resolution spectrum in the full visible range was acquired. The principal-component analysis technique was used to obtain thematic maps that outlined areas subject to protective treatment and biological growth, and other features, such as different types of stones and decoration pigments.

Petrophysical characteristics of the sandstones used in the construction of the Monumental Heritage of Ciudad Rodrigo, Salamanca. Spain

Knowledge of the petrophysical characteristics of stones used in construction is evidently advantageous in the sense that it can help avoid wasting time and future disappointments when attempting to assess the results both in restoration work and in actual construction work. However, if the material used is sandstone, as in the case addressed here, such knowledge is even more pertinent since such materials are soft and porous. Here we offer an exhaustive study of the petrophysical characteristics of the sandstones used in the construction of the Monumental Heritage of Ciudad Rodrigo (Salamanca, Spain). Five different types of stone were used; namely, the Red, Brown, Striped, Nodular and White, varieties. The differences among these varieties lie in the degree of diagenetic transformation they have undergone. Each of them has important mineralogical, textural and structural differences as compared with its counterparts, implying that each variety will behave differently when used for construction purposes. The Red variety is the least transformed and hence the least suitable for construction. By contrast, the White is the variety that has undergone the greatest degree of diagenesis and is hence the most appropriate for such purposes.

« Stela of Urnammu » fragments in London

fragments of sculpture classified as the of Urnammu were mainly excavated at Ur by C. L. Woolley in 1924—25, working on behalf of the British Museum and the University Museum, Philadelphia. It was decided that they should ail be sent to Philadelphia, and in principle that is what happened. It was later notieed, however, that two radiate sun-disk fragments had been treated as part of an Utuhegal monument in a different stone, and kept in the Department of the Ancient Near East at the British Museum (J. E. Reade, The Utuhegal stela from Ur, Baghdader Mitteilungen 27 [1996]: 229—34, Taf. 21—2). These sun-disk fragments have not been incorporated into the new reconstruction by J. Y. Canby, Ur-Nammu Stela (University Museum Monograph 110; Philadelphia, 2001), pis 10—11, but there is no immediately obvious reason why they should not both be placed near the top of her pl. 11, rather than being regarded as belonging to one of about other stelae in different types of stone (ead.: 6). It also seems possible that the figure of seven is too high, since the main stela is made of a layered stone which may occasionally have split and required patching during manufacture; in that case different types of stone could have been used for repairs, and the differences would not have been visible if the stela was then painted. A further corner fragment of stela was identified in 1996, and is illustrated here, Figures 1—2. It has now been incorporated, with a direct join to a piece in Philadelphia, into Canby's reconstruction (ead.: 37, pis 11, 52, no. 66b: 1927—5—27, 1 = 118545). retention of this piece in London, and other inappropriate separations of Ur material, which continue to cause confusion, are explained partly by attitudes to antiquities then current, and partly by the system employed in allocating objects and by the personalities involved, as described by H. Y. F. Winstone, Woolley of Ur (London, 1990), p. 130, 133, 184-189.

Prediction of gall stone composition by ultrasound: implications for non-surgical therapy.

Oral cholecystography is the basic radiodiagnostic procedure required to assess chemical composition of gallstones as well as functional status of gall bladder prior to non-surgical management of gallstones. However, the value of ultrasound in non-surgical management of gallstones is yet to be proved. In this study we attempt to establish sonographic criteria which will predict the composition of gallstones prior to their non-surgical treatment. For this purpose the ultrasonographic characteristics of 233 patients with gallstone disease and functioning gall bladders were studied and an effort was made to correlate cholesterol and calcium content of different types of stones (as estimated by X-Ray powder diffraction study and atomic absorption spectrophotometry) with their ultrasonographic characteristics. Sonographic criteria for the presence of cholesterol stones were those which were floating and gallstones producing acoustic shadowing without internal echoes from within the stone. In detecting findings which would predict the presence of cholesterol stones on ultrasound, ultrasound had a sensitivity of 72.90% and a specificity of 100%. The predictive values of positive findings and negative findings were 100% and 93.4%, respectively. The demonstration of typical features of cholesterol stones on ultrasound obviates the need for oral cholecystography.

Biliary Sludge

Biliary sludge has been for many years a poorly defined entity, usually with low amplitude, nonshadowing echoes within the most dependent part of the gallbladder, which shift under the influence of postural changes. From a sonographic point of view, the detection of sludge implies the coexistence of small-sized, solid components and of a gel-like embedding material. The chemical nature of biliary sludge has recently been recognized to be predominantly composed of a coaggregate of cholesterol monohydrate crystals and liquid crystalline droplets, and in some cases, such as obstructive jaundice or symptomatic liver diseases, by bilirubin granules, all embedded in a gel matrix of mucous glycoproteins. From a pathogenic point of view, biliary sludge is often associated with biliary stasis, or with conditions characterized by impaired gallbladder contraction, such as prolonged total parenteral nutrition, fasting, and pregnancy. Other causes include mucus hypersecretion, which may favor cholesterol nucleation and crystal growth, and bile infection. Sludge may be an intermediate step in the formation of different types of stones. From an epidemiological point of view, sludge is quite rare in the asymptomatic, free-living population, but may be common in selected series of symptomatic patients. From a clinical point of view, sludge often has a fluctuating course, including frequent disappearances and reappearances, suggesting that the early stages of gallstone formation are reversible.

Environment And Deterioration OfArchitectural Materials

SUMMARY. A study was made of a series of monuments located in the city of Valencia, built with different types of stone, and pertaining to different ages. Our intention was to verify the degree of influence that both climatological agents and atmospheric pollution had in their weathering. The techniques used were as follows: some of the physical experiments from those recommended by international institutions (Rilem), microscopies: reflection, petrographic, TEM and SEM techniques, with X-Ray microanalysis, and chemical analysis of soluble salts in lithofacies, which have provided very meaningful data.