Round Stones Research Articles

Desert pavement development on the lake shorelines of Lake Eyre (South), South Australia

To the southwest of Lake Eyre (South), South Australia, silcrete boulders exposed by the erosion of the surrounding fine sediments undergo mechanical weathering to form desert pavement. Successive palaeoshorelines of Lake Eyre have exposed an age-related sequence of different stages in the weathering of the boulders. This study investigates desert pavement development in this saline environment. In addition, it attempts to develop a model for the development of desert pavement following exposure of the silcrete boulders, based on palaeo-lake shorelines dated from previous studies. Seven stages can be recognised corresponding to stages of soil and pavement development. Prior to stage one is the actual exposure of the boulder as the result of erosion by wave action at the lake shoreline or by erosion as the lake level falls during desiccation. At stage-1 the upper surface of the boulder breaks up through mechanical weathering (salt weathering), while the rest of the boulder is still buried. At stage-2 the surface fragments fall to the edge of the stone and expose more of the stone, which continues to break-up. There is no soil development in stages 1 and 2. By stage-3 most of the stone is exposed and broken up, making a mini-hill. At this stage soil development begins with the accumulation of sandy soil between the rock fragments. At stage-4 the stones form small cones and the soil is more developed. It is sandy with a typical of colour 10 YR 6/6. At stage-5 the stones forming the small cone are completely fragmented. Stone fragments at the centre are very angular but smoother at the edges of the mini-hill as the result of weathering (etching by chemical processes?). Soil texture is silty/sand and soil colour is 7.5 YR 6/6. At stage-6 the surface is nearly flat. The soil is sandy/silt and soil colour is between 7.5 YR 5/6 and 7.5 YR 5/8. Stage-7a is the gibber plain phase, composed of small well rounded stones, as a result of continued etching of the edges of the fragmented stones. The soil is silty, and the soil colour is between 5 YR 5/6 and 5 YR 5/8. Stage-7b is also gibber plain, with small well rounded stone fragments but where the soil has been replaced by crystalline gypsum. This sequence differs from sequences described in other areas, especially on alluvial fan or terrace surfaces. This may be partly due to the different origin of the clasts, as “pre-weathered” silcrete boulders, and partly due to the importance of chemical weathering by “etching” in this salt-rich environment.

Recognition of Paleogastroliths from the Lower Cretaceous Cedar Mountain Formation, Utah using a Scanning Electron Microscope

Paleogastroliths, as defined in this study, are stomach stones associated exclusively with extinct animals. Definitive recognition of paleogastroliths is problematic and controversial. Polished, rounded stones found within skeletal remains of dinosaurs and plesiosaurs are the strongest evidence. This study examined intraskeletal and proposed paleogastroliths using a scanning electron microscope (SEM) to determine if any defining surface textures occur. Paleogastroliths associated with the skeletal remains of Seismosaurus hallorum, possible paleogastroliths from the Lower Cretaceous Cedar Mountain Formation, and other well-polished stones were obtained. Most stones were composed of either quartzite or chert and were examined with a SEM at magnifications ranging from 100× to 400×. All of the cherty Seismosaurus hallorum stones contained sets of parallel to sub-parallel, curved polish grooves that in places crosscut one another. These grooves are inferred to have formed as the result of small particles lodged in the stomach muscles interacting with the stones due to muscle movement. The distinctive surface textures noted on the cherty Seismosaurus hallorum paleogastroliths are similar to those seen on the cherty possible paleogastroliths from the Cedar Mountain Formation. Therefore, the geologic occurrence combined with the microscopic surface texture supports the interpretation that these stones are paleogastroliths.

Dust Measurements in the Egyptian Northwest Coastal Zone

Standard dust sampling equipment was used to collect eroded aerosol samples from 52 wind erosion events in the Northwest Coastal Zone (NWCZ) of Egypt. The eroded samples were analyzed to determine the transport mass for each erosion event over a 3-year period from farm fields at Fuka and Abu Lahu. Weather, soil roughness, rock cover, and vegetative cover data were collected to provide input to the Revised Wind Erosion Equation (RWEQ) model to estimate transport mass. Annual rainfall in the NWCZ is much lower, soils have more surface stones, and crop planting and harvesting methods are much different from test sites in the U.S., where similar wind erosion studies on transport mass have been conducted. The soil at Fuka is 2.3 times more erodible by wind than the soil at Abu Lahu. Stone cover varied from 0% to 30% and 0% to 27%, and vegetative cover varied from 0% to 18% and 2% to 50% at Abu Lahu and Fuka, respectively. Soil ridge height was 0 to 10 cm and ridge spacing was 40 cm at both sites. Because of the large stones at Fuka and numerous round stones at Abu Lahu, a stone silhouette coefficient (Ssc) was developed in the Desert Research Institute at Cairo and used to estimate transport mass with RWEQ. Fifty-six percent and 62% of the erosion events in the NWCZ occurred in February, March, or April, and 59% and 83% of the events lasted between 11 to 20 h at Fuka and Abu Lahu, respectively. Maximum measured transport mass was 261.7 kg/m-width at Abu Lahu and 737.5 kg/m-width at Fuka. Maximum estimated transport mass with RWEQ was 285.9 kg/m-width at Abu Lahu and 649.8 kg/m-width at Fuka. The coefficient of determination was r2 = 0.93 for 60 clusters of measured and estimated transport mass at Fuka. For 44 clusters of measured and estimated transport mass at Abu Lahu, the coefficient of determination was r2 = 0.91. The RWEQ model with the stone silhouette coefficient can be used to describe wind erosion in the semi-arid Northwest Coastal Zone of Egypt. The RWEQ model can also be used to evaluate new management systems that utilize available resources to minimize wind erosion.

Weathering damage evaluation of rock properties in the Bunhwangsa temple stone pagoda, Gyeongju, Republic of Korea

The stone pagoda of the Bunhwangsa temple in Republic of Korea was made of piling small brick-shaped stones. The majority of stone bricks are andesitic rocks with variable geneses. Rock properties of the pagoda roof suffer partial significant deterioration, such as multiple peel-offs, exfoliation, onion-peel-like decomposition, cracks forming round lines and falling-off stone pieces. The stylobates and tabernacles at the four corners are composed of granitic rocks, which are heavily contaminated by lichens and mosses. Some of these contamination marks show dark black or yellowish brown colors by inorganic secondary hydrates. The four tabernacles and northern face of the pagoda body have been exposed to relatively high humidity, which causes light gray efflorescence as stalactites between the northern and western sides of the body. The efflorescences are composed of calcite, gypsum and clay minerals. The stone lion statues at the southeast and northeast corners are made of alkali granite, while the others are lithic tuff. Total rock properties of the pagoda consist of 9,708 stone bricks. Among them, 11.0% are fractured, 6.7% are fallen off, and 7.0% show considerable surface efflorescence, which shows that the pagoda has been highly deteriorated by physical, chemical and biological weathering. The authors strongly suggest long-term monitoring and comprehensive conservation researches.

６７個の耳下腺唾石症例

Sialolithiasis is often found in the submandibular gland, but rarely in the parotid gland. In most cases sialoliths tend to exist in one side. We encountered a very interesting case who had 67 sialoliths in both sides of the parotid gland. A 70-year-old woman underwent an intraoral operation to remove the stones, two large round stones in the right cheek and 65 small stones in the left cheek. The post operation course was uneventful.

Lying for the Whetstone: A Saying and its Links with Folk Life and Tradition

Whatever their importance today, whetstones were once vital. Every so often, maybe four times an hour, the wielder of scythe or sickle would need to sharpen his blade. Without this, his work would have been impossible, and the crops on which all depended could not have been harvested. The names and types of whetstone and pouch varied from place to place. North Yorkshire and many adjacent areas knew the strickle, once described as ‘a four-sided implement of oak, some twelve or fourteen inches long (without the handle), and tapering to a point’. The sides were greased and then dressed over with lea-sand (‘fine gritty sand for sharpening scythes alias leas’). In some parts of Kent a distinction was made between a rubber and a rubber bat. The former was a round stone for sharpening the scythe, while the latter was a flat stone used when the metal was soft, so as not to tear it. In Gloucestershire a mower would use a riffle. This was a short wooden dagger or rapier, with which he smoothed the edge of his implement after applying the coarse whetstone. Your Dorset scythesman kept his daker in a budget, or leathern pouch, while in parts of Devon the balker alias Devonshire bat was carried in a balker-pooch at the back of the buckle strap, that is, the leathern strap worn about the waist.

Habitat and Microhabitat of Mediterranean Clingfishes (Teleostei: Gobiesociformes: Gobiesocidae)

Abstract. This study addresses the habitat and microhabitat of the seven species of gobiesocid fish in the Mediterranean Sea. It is shown that Lepadogaster lepadogaster is closely adapted to large pebbles and boulder fields of rounded stones with a smooth surface. L. candollei is more euryecious and, in addition to inhabiting boulder fields also, occurs close to seagrass meadows, in small cavities and in association with sea urchins. Diplecogaster bimaculata is also euryecious and extends to greater depths. It lives on sand and muddy bottoms as well as on coralline grounds. At some locations this species is found in high abundance during the spawning season under empty bivalve shells or flat stones. Apletodon dentatus is the rarest species of Gobiesocidae in the Mediterranean Sea. It has a close association with seagrass or large brown algae (Cystoseira). Juveniles of A. incognitus are either associated with sea urchins or inhabit Posidonia meadows. Adults prefer the vicinity of seagrass meadows under empty bivalve shells and stones overgrown with red algae. Gouania wildenowi is stenoecious and is restricted to the interstices of roundish coarse gravel near the waterline. Opeatogenys gracilis is also stenoecious and lives only on the leaves of Posidonia and Cymodocea seagrass. The colourations of the different species and their variations are described and discussed.

L'apparition des premiers engins balistiques dans le monde grec et hellénisé : un état de la question

The discovery, first at Paphos and then at Phocea, of medium-caliber round stone projectiles dating from a period preceding the fourth century B.C. have justly led researchers to ponder the invention of the lithobolos and its date of appearance in the Greek world. Reexamination of the literary texts relative to military techniques and tactics (both Greek and Persian), and the study of the archaeological environment in which these projectiles were discovered tend to rule out the hypothesis according to which the lithobolos was developed by the Persians as early as the sixth and fifth centuries. We must keep the traditionnal dating and consider that it was the Macedonians who first used a catapult with round stone projectiles. In 334, during the siege of Halicarnassus, Alexander was already using lithoboloi at torsion, which marked a real advance in the realm of military engineering.

Scattered round stones: a Mayo village in Sonora, Mexico

Scattered round stones: a Mayo village in Sonora, Mexico

Therapeutic endoscopy: removal of gastrointestinal foreign bodies in children.

Endoscopic removal of foreign bodies (FBs) is an important part of therapeutic endoscopy in children. The majority of FB ingestion occur in children under 5 years. Children most often ingest coins, pins, keys, round stones or marbles, nails, rings, batteries and toys, and coins are the most common in the pediatric series of 139 children, who underwent endoscopic removal in Seoul National University, Children's Hospital. The management of FBs in children depends on the type (sharp or dull, pointed or blunt, and toxic or nontoxic) and the-size, along with the location of FB in the gastrointestinal tract. The endoscopist should decide whether endoscopic intervention is necessary and how urgently it has to be done. Indications for removal of FBs from the gastrointestinal tract in children are 1) all esophageal FBs. 2) gastric and duodenal FBs if they are sharp or pointed, if more than 4 cm long or 2 cm wide in young infants and children, if containing toxic substances and if blunt objects after 2 weeks observation in the stomach or 1 week observation in the duodenum. All FBs impacted in the esophagus should be removed within 24 hours because of the risks of perforation and serious fistula formation. Disk batteries can cause corrosive injury to the esophagus within 4 hours, and should be removed as soon as possible. Coin retrieval can be done very securely by the W-shape FB grasping forcep without an endotracheal general anesthesia. Blunt FBs, such as marbles can be best removed with a stone retrieval basket, which can be made from a condom. Disk batteries can not be grasped with the FB forceps and snares, but very safely with the powerful magnet attached to the tip of the scope. Overtubes and protective rubber hoods are useful for removing sharp or pointed objects. It is important to test the available grasping accessories on a duplicate of the FB as a "dry run" to determine which accessories will grasp the FB securely.

Image segmentation to inspect 3‐D object sizes

Object size inspection is an important task and has various applications in computer vision. For example, the automatic control of stone-breaking machines, which perform better if the sizes of the stones to be broken can be predicted. An algorithm is proposed for image segmentation in size inspection for almost round stones with high or low texture. Although our experiments are focused on stones, the algorithm can be applied to other 3-D objects, We use one fixed camera and four light sources at four different positions one at a time, to take four images. Then we compute the image differences and binarize them to extract edges. We explain, step by step, the photographing, the edge extraction, the noise removal, and the edge gap filling. Experimental results are presented.

Theoretical Analysis of Geomembrane Puncture

A theoretical analysis of the mechanism of geomembrane puncture based on a simple model is presented. The analysis shows that the geomembrane puncture resistance depends on the diameter of the contact area between the geomembrane and the puncturing object, the thickness of the geomembrane, and the tensile characteristics of the geomembrane. An equation is established that makes it possible to express the geomembrane puncture resistance measured in a probe test as a function of the geomembrane characteristics and the diameter of the probe. Predictions made with this equation are found to be consistent with the limited laboratory test data which were reviewed. The analysis is then used to establish a relationship between a geomembrane resistance to puncture measured in a laboratory probe test and the resistance to puncture of a geomembrane subjected to pressure applied by a liquid while resting on a layer of stones of approximately uniform size and shape. A special relationship is presented for the case of rounded stones. The paper also presents relationships between geomembrane resistances to puncture by stones under different sets of conditions characterized by the stone size and shape, and the geomembrane thickness and tensile characteristics. The use of these relationships is illustrated by design examples.

Brittleness of gallstones to lithotripsy: effect of physicochemical and ultrastructural characteristics

Why some gallstones do not fragment easily to lithotripsy is unclear. The aim of the present study was to determine gallstone factors associated with resistance to fragmentation. Seventy-six cholesterol rich gallstones were subjected to physical evaluation, in vitro computed tomography, chemical analysis by infra red spectroscopy, and ultrastructural studies (of 26 matched stones) by scanning electron microscopy and energy dispersive X-ray microanalysis. In vitro lithotripsy was performed with the Siemens Lithostar Plus machine at a constant energy level. Of 76 stones, 33 required > 1000 shocks for effective fragmentation (largest diameter < or = 5 mm); they had significantly higher maximum diameter (P < 0.001), volume (P < 0.001), weight (P < 0.001) and lower stone density distribution (SDD) index (P < 0.05) and lower calcium bilirubinate content (P < 0.001) than those requiring < or = 1000 shocks. Large (> 15 mm; P < 0.05), round stones (P < 0.02) and gallstones with SDD index of < 50 HU (P < 0.02) and gallstones with SDD index of < 50 HU (P < 0.05) were more difficult to fragment. Clinical application of these parameters may help in better selection of patients for this non-surgical mode of therapy for gallstones.

In Vitro Calcium Oxalate Lithotripsy: Comparison of Dornier HM3 and Siemens Lithostar

In vitro lithotripsy of round calcium oxalate stones retrieved from a patient at pyelolithotomy was used to compare the Dornier HM3 and Siemens Lithostar lithotripters. Similar stones were subjected to the same number of shock waves at similar kilovoltages and shock wave frequencies, and percent fragmentation was calculated. The numbers of shock waves required to fragment similar stones completely at the same kilovoltages were determined. Using 50 shock waves at less than 16 kV, the Siemens Lithostar produced little fragmentation of like stones, while at 16 kV and above, the Lithostar and the Dornier HM3 yielded similar stone fragmentation. The number of shock waves required to obtain complete fragmentation was similar for the HM3 and the Lithostar at greater than 16 kV. Using energy levels less than 16 kV, the HM3 needed markedly fewer shock waves to achieve fragmentation, although complete fragmentation could be accomplished with the Lithostar.

A comparison of a straw-based and slatted floor housing system for the weaned pig

Little objective information is available on the relative merits of straw based and slatted floored systems for the weaned pig in terms of performance and indices of welfare. A controlled experiment was conducted in an attempt to obtain relevant information.The following 3 systems were compared: (1) straw bedded pens (SB), conventional flat decks (FD) and identical flat decks with environmental enrichment (FD+). The FD pens had fully perforated expanded metal floors with an ad lib feeder across the front of the pen and 2 nipple drinkers on the opposite wall. The enriched FD pens had a variety of ‘recreational’ objects added - a metal chain and tyre suspended from the ceiling within the pigs’ reach, a concrete block, a tyre and an assortment of rounded stones of different size placed on the pen floor. There were 3 pens per room but only 2 were used in the trial, one each for the FD and FD+ treatments. Temperature control was by means of 2 gas heaters and a fan assisted ventilation system which was thermostatically controlled. The straw pens were located in a large cattle court which had a concrete floor; within each pen there was a kennelled lying area and an open outrun. The whole floor surface was kept liberally covered with good quality dry barley straw. An identical ad lib feeder to that in the flat decks was provided in the outrun area and 2 nipple drinkers were provided adjacent to the feeder. In all treatments for the first 3 days of the trial a box drinker was placed in each pen to allow the pigs time to familiarise themselves with the nipple drinkers.

A Study in Sourcing Hohokam Basalt Ground Stone Implements

ABSTRACTGround stone implements were important tools for the Hohokam because they relied heavily on plant foods in their diet. Current data suggest that in the Phoenix Basin vesicular basalt materials were favored for the rectangular mano and trough metates common at most Hohokam sites. The distribution of basaltic materials is relatively limited' however, and specific outcrops were exploited as quarries. Experiments with low-power reflected light and BSE-EDX microscopic sourcing techniques indicate that several regional basalt sources exist, and that these sources may be identifiable in ground stone assemblages. The composition of various source materials at different sites has the potential to provide insights into Hohokam ground stone production and trade.

A study of the stability of dynamically stable breakwaters

The effect of gradation of armour stones and the amount of rounded stones in the armour on dynamically stable breakwaters was assessed in a two-dimensional wave flume. A total of 52 series of tests were undertaken at the Coastal Engineering Research Laboratory of Queen's University, Kingston, Canada using irregular waves. Profiles of the structure during the various stages of reshaping were measured using a semiautomatic profiler developed for this study. Four gradations of armour stones were used, giving a range in uniformity coefficient of 1.35–5.4. The volume of stones and the initial berm width required for the development of a stable profile, along with the extent to which the toe of the structure progressed seaward, were chosen as representative parameters of the reshaped breakwater. The results indicated that the toe width formed as a result of reshaping and the area of stones required for reshaping were dependent on the gradation of the armour stones. The initial berm width required for reshaping was also found to be dependent on the gradation and the percentage of rounded stones in the armour. Key words: breakwaters, dynamic stability, hydraulic models, stability, armour stones.

On Subglacial Stone Pavements in Till

Four pavements from central and western Canada display uneven pavement surfaces, abundant tilted and inverted stones, reversed lee ends, fine crossing striae in various directions, weak striae around curves, worn facets distributed evenly on rounded stones, and till fabric girdles; collectively inconsistent with the popular concept of stones firmly held in till being abraded by overriding ice. Based on these data, new models are offered that involve stone rotation in viscously deforming till to produce deformation pavements. In the specific model, increased pore water pressure under moving ice locally mobilizes previously formed lodgment and/or erosional pavements into deformation pavements. In the more general model stones released from the sole of a wet-based glacier rotate, interact, and settle into a viscous suspension zone in deforming till according to velocity, density, and viscosity gradients. Stone axes and striae settle into various orientations following dewatering and till stiffening. Conceptually, pavement types include lodgment, deformation, meltout, and erosional formed by end-member processes in a continuum schematically depicted in a pavement prism. Pavements of this study are hybrids, and probably so are many others. An abundance of deformation-dominated pavements in an area has important implications as a record for rapid glacier flow that influences the stability of ice sheets.

The influence of armour stone gradation on dynamically stable breakwaters

Dynamically stable or berm breakwaters are structures in which the armour layer is comprised of a wide range of stone sizes and undergoes reshaping in response to wave action. As a result of this wave action, a stable profile is achieved. The effect of gradation of armour stones and the amount of rounded stones in the armour on dynamically stable breakwaters was assessed in a two-dimensional wave flume. A total of 52 series of tests were undertaken at the Coastal Engineering Research Laboratory of Queen's University, Kingston (Canada), using irregular waves. Profiles of the structure during the various stages of reshaping were measured using a semi-automatic profiler developed for this study. Four gradations of armour stones were used giving a range in uniformity coefficient ( D 85/ D 15) of 1.35 to 5.4. The core of the breakwaters was relatively permeable. The volume of stones and the initial berm width required for development of a stable profile along with the extent to which the toe of the structure progressed seaward were chosen as representative parameters of the reshaped breakwater. The results indicated that the toe width formed as a result of reshaping and the volume of stones required for reshaping were dependent on the gradation of the armour stone. The initial berm width required for reshaping was also found to be dependent on the gradation and the percentage of rounded stones in the armour.

Letters to the gods: The form and meaning of ema

the votive tablets upon which people write requests and imprecations to the deities and buddhas, are perhaps the most conspicuous and colorful of all the numerous talismanic and religious objects commonly found at Shinto shrines and Buddhist temples in Japan. Unlike protective amulets and talismans such as o-mamori 9,9 and fuda L , which are considered to contain the sacred powers of the deities enshrined at the religious site and which are taken away as representations and symbols of that power, ema are left at the site to act as a medium through which the wishes and needs of supplicants may be made known to the figures of worship enshrined there. They are not the only objects to operate in this way, for various other objects, including round stones and the slender wooden sticks known as gomagi ~J , which are later consigned to the flames of the ritual fire ceremony known as goma a