Rim Diameter Research Articles

Majolica escudillas of the 15th and 16th centuries: A typological analysis of 55 examples from Qsar es-Seghir

This paper examines in detail 55 complete or near complete, unpainted carinated majolica bowls (Columbia Plain) from Qsar es-Seghir (Alcacer Ceguer), a Portuguese garrison in northern Morocco occupied from 1458 to 1550. Base type, rim diameter, glaze type, and presence of handles are found to vary significantly through time. The collection is interesting from a comparative point of view with similar or identical bowls found in 16th century Hispanic sites in the New World.

The Manicouagan Impact Structure: An analysis of its original dimensions and form

Manicouagan, Quebec (51°23'N; 68°42'W) is the most intensively studied large complex terrestrial impact structure in a predominantly crystalline target. The ground truth data available from Manicouagan have considerable potential for interpreting the subsurface characteristics of lunar impact structures of comparable morphology and size. Two contrasting hypotheses, however, exist for the preerosional form of Manicouagan: (1) a multi‐ring basin with a final diameter of 75 km and a transient cavity diameter of 30–45 km [Floran and Dence, 1976], and (2) an endogenically modified peak‐ring basin with a final diameter of 100 km and a transient cavity diameter of 80 km [Orphal and Schultz, 1978]. Both hypotheses are based largely on topographic data and interpret the prominent 65 km diameter annular moat as a graben‐like feature formed either (1) by collapse of the outer slope of the transient cavity rim or (2) by uplift of the final crater floor through post‐impact intrusive activity.The present analysis suggests that this annular moat is primarily an erosional feature and that the original form of the impact structure cannot be determined unequivocally on the basis of present topography. If all the available topographic, geologic, and geophysical data are considered, however, then an internally consistent interpretation of original dimensions is possible. The distribution of shock deformation effects in the basement rocks of the present crater floor suggests an original transient cavity diameter of 60 km. The 55 km‐diameter, impact melt‐covered inner plateau provides a minimum estimate for the diameter of the final floor of the crater and the annular moat, with its outliers of downdropped Ordovician limestone, is interpreted as marking the contact between the floor and the innermost slump blocks of the final rim. There is no compelling evidence to regard the annular moat as a graben. By analogy with fresh lunar and mercurian structures, a floor width of 55 km suggests a final rim diameter of 86–95 km. This is consistent with the topographic data from outside the annular moat and with the residual peripheral gravity low, which suggests a final rim diameter of 85–95 km. Due to erosion, it is difficult to assign Manicouagan to a particular morphological class of impact structure, but on the basis of the available data it is most likely that the preerosional form was that of a central peak crater or possibly a peak‐ring basin. At the time of its formation, Manicouagan may have been dimensionally and possibly morphologically similar to the 96 km diameter lunar crater Copernicus.

Volumetric analysis of complex lunar craters: Implications for basin ring formation

The transition in hypervelocity impact structures from complex craters to basins is defined by a transition in uplifted central features from peaks to peak rings. Volumetric and morphologic analyses of the central peaks in complex lunar craters are combined with subsurface data from terrestrial complex impact structures in an effort to characterize the crater to basin transition. Central peak volumes in lunar craters with rim diameters (Drc) < 51 km follow a power‐law relationship to apparent crater volume. In craters with Drc > 80 km, central peak volume is relatively reduced and a second power‐law relationship is defined. The relative reduction in peak volume in craters with Drc > 80 km is associated with a relative decrease in peak height, and is accompanied by the development of a concentric zone of enhanced floor roughening. Studies of terrestrial complex impact structures suggest that the amount of uplifted material, as judged from its depth of origin, continues to increase with increasing rim diameter. This suggests that a redistribution of uplifted material away from a centralized peak may occur in the larger craters. The volumetric and morphologic changes described occur over a rim diameter range of 51–80 km, far below the previously proposed range for the crater to basin transition (Drc = 140–175 km). Evidence is presented to support a crater to basin transition beginning at Drc = 51–80 km, characterized by a relative reduction in central peak volume and the development of rings of floor roughening, which are suggested to be precursors of peak ring development.

Manufacture of large castings in permanent molds

A new technological process has been introduced for manufacturing large cast-iron pulley blanks in permanent molds. The pulley casting weighs 137 kg and has a rim diameter of 650 mm. The permanent mold is split horizontally. Before pouring metal the mold is heated with a gas torch to a temperature of 200-250/sup 0/C and coated with a layer of thermal insulation material. The molten metal is poured at a temperature of 1280-1300/sup 0/C within a period of 40-50 seconds. The casting is held in the mold for 4-5 minutes. A simple pneumatic machine has been designed for ejecting the castings. The permanent mold, being made of cast iron, can be used for more than 500 castings. Introduction of the new technological process for casting pulleys in permanent molds has reduced the labor requirement by four times, eliminated rejections caused by using sand molds, and improved the working conditions.

The Lake Bosumtwi impact crater, Ghana

The 1-m.y.-old Bosumtwi Crater, Ghana, has a nearly circular shape with a rim diameter of 11 km north-south and 10 km east-west. It is surrounded by a circular depression and an outer ridge of diameter 20 km. Polymict breccias averaging at least 20 m thick with clasts as much as 5 m long occur on the outer ridge, and the crater rim shows in situ shattered rock. Patches of suevite have been found in the circular depression north and south of the crater. Analogy with better-known craters suggests that Bosumtwi has a central uplift rising to 200 m beneath the lake floor. An aeromagnetic anomaly of amplitude 50 nanotesla (nT) over the northern half of the lake is interpreted as due to a layer of magnetized fallback breccia beneath the lake sediments. The normal polarity of the breccia shows that the crater was formed during the normal Jaramillo event of 0.97 to 0.85 m.y. ago, which agrees with the magnetic stratigraphy of the related Ivory Coast microtektites. A regional gravity survey indicates a negative Bouguer anomaly over the crater. There is some geochemical evidence that the meteorite was an iron, and its mass and energy are suggested as about 108 tons and 3 × 1019 joules or 7.3 × 103 megatons.

Visualization of pores (export sites) correlated with cellulose production in the envelope of the gram-negative bacterium Acetobacter xylinum.

The Gram-negative bacterium Acetobacter xylinum assembles a cellulse ribbon composed of a number of microfibrils in the longitudinal axis of its envelope. The zone of ribbon assembly was investigated by freeze-etch electron microscopy. Freeze-etching revealed, beneath the cellulose ribbons, a linear array of pores on the lipopolysaccharide membrane. These pores have a rim diameter of 120--150 A and a central hole or deepening of approximately 35 A. The axes of pore arrays closely coincide with linear arrays of 100 A particles on the E- and P-faces of the fractured lipopolysaccharide membranes. Pores and particles in the lipopolysaccharide membrane are probably congruent. The pores are hypothesized to be the export sites (penetration sites) for cellulose.

The nature of the gravity anomalies associated with large young lunar craters

The negative Bouguer anomalies (i.e., mass deficiencies) associated with four young lunar craters are analyzed. Model calculations based on generalizations made from studies of terrestrial impact structures suggest that the major contribution to the Bouguer anomaly for these lunar craters is due to a lens of brecciated material confined within the present crater rim crest and extending vertically to at least a depth of one‐third the crater rim diameter. Calculations also reveal a systematic variation in the magnitude of the mass deficiencies with the cube of the crater diameter.

A presumptive subunit of elastic fiber microfibrils secreted by arterial smooth-muscle cells in culture.

Monkey smooth cells, maintained for five weeks in confluent cultures, accumulated a substantial extracellular matrix. Elastic fibers possessing the characteristic amorphous elastin component and 11 nm diameter microfibrils could be isolated from this matrix by extraction with 5 M guanidine. Further extraction under reducing conditions selectively removed the microfibrillar component. Gel electrophoresis of this extract in the presence of sodium dodecylsulfate revealed a single protein band with an apparent molecular weight of 270000. The amino acid composition of this presumptive subunit of the microfibrillar protein was rich in acidic and hydrophilic amino acids and distinctly different from that of collagen or elastin. When smooth muscle cell cultures were incubated with labeled cystine, the predominant labeled protein in the culture medium also had a molecular weight of 270000. This labeled protein comigrated with a major protein band and could be partially purified by DEAE-cellulose ion-exchange chromatography and gel filtration on agarose. It shared manu of the properites of the presumptive microfibrillar protein.

Research on Force-Fitted Gear : Part 10-Deformation in each part of gear rim caused by force-fitting

The main object of this paper to to examine the influences of force-fitting conditions, kinds of material, method of heat treatment, thickness of gear rim and size of tooth upon the deformation in each part of gear rim (diameter of tip cylinder, diameter of root cylinder, displacement over a given number of teeth, tooth profile, lead and normal pitch, etc.). From the experiments it is found that the larger the interference and the smaller the gear rim thickness and size of tooth, the larger becomes the deformation in each part of gear rim mentioned above, and deformation of tooth profile is hardly influenced by kinds of material of gear rim and method of heat treating.

A late-Quaternary monogenetic volcano field in central Mexico

The western end of the “Grupo Chichinautzin“, a segment of the east-west Mexican Volcanic Belt, contains 41 volcanic cones and associated lava flows, ranging in age from 8,390±100 to 40,000 years BP. There are two main cone types: cinder cones and cones made up mainly of lava blocks. The cone density is 0.1/km2 and the height range is 15 m–260 m with crater rim diameters of from 175 m to 500 m (mean 280 m). The relative ages of the volcanoes and flows were established using geomorphological parameters. With increasing age, height/width ratios decrease from 0.21 to 0.10 whilst the ratio of crater width to basal width increases from 0.40 to 0.83. Three of the cinder cones produced a total of > 0.75 km3 of ash covering > 200 km2. The other cone type appears to have erupted only small amounts of ash. The lava flows are of aa or block lava with an average thickness from 10 m to 70 m and a maximum length of 1 km to 13.5 km. The aspect ratio varies from 20 to 120. The younger, Holocene, flows, made up mainly of two-pyroxene andesites, are longer, thinner, and originally less viscous than the shorter, thicker flows from the older volcanoes which are relatively richer in olivine. The Holocene flows cover ∼ 115 km2 with a volume of ∼ 4.5 km3. The rocks contain 52% to 64% SiO2 and are essentially andesitic but some extremes could be classified as alkalic basalts and dacites. Sufficient parameters are available to characterize the “violent strombolian” eruptions of this volcano field, which show features of both hawaiian and normal strombolian activity.

Advances in Tire Technology Introduction to Symposium. (Cleveland, Ohio, April 24, 1968)

Abstract The current interest in tires, transportation, and passenger safety in highway vehicles, prompted this symposium on advances in tire technology. Everyone is familiar with tires, at least to the degree that he recognizes them on his car. It seems the average layman thinks a tire is something that is somehow put together and thrown into a mold where it is given shape, but he has little conception of the compound, construction, or design engineering required. We are also hearing new as well as old names. Of tire types there are such names as bias, bias belted, and radial; of cord types such names as rayon, Tyrex, nylon, polyester, glass, and wire. You hear other terms such as wide oval, wide tread, aspect ratio, rim diameter, white wall, red ring, high performance, and many more. The tire carries the load, absorbs shocks, withstands impacts, goes through mud, ice and snow, and gives the consumer a minimum concern and minimum cost in spite of the ever increasing requirements placed on it.

Tactual coding of cylindrical knobs.

Tactual coding of knobs by use of bizarre shapes is frequently achieved at the expense of manipulability and setting precision, which appear, in many cases, to be optimal when knobs are cyclindrical. In order to be able to maximize both discriminability and manipulability, certain parameters of cylindrical knobs were investigated as bases for tactual coding. Rim surface, diameter and thickness were all found to be useful for this purpose. When feeling one of two knobs whose pictures were before them, subjects rarely (less than 1% of the time) identified the wrong picture as the felt knob in any of the following situations: diameters differ by 1/2 inch or more, thicknesses differ by 3/8 inch or more, rim surfaces belong to different ones of the three families: smooth, fluted, knurled.

En jordgrav fra tidlig-neolitisk tid

En jordgrav fra tidlig-neolitisk tid

Hjulgraven fra Storehøj ved Tobøl i Ribe Amt

Hjulgraven fra Storehøj ved Tobøl i Ribe Amt

Some Samian ware of Form 72

The samian bowl, of form 72 with barbotine and appliqué designs in relief, illustrated in fig. 1, was found in 1958 during a small excavation carried out in connexion with rebuilding work at Guy's New House, Bermondsey; it has already been briefly noticed in the Journal of Roman Studies.This globular bowl (ht. 7⅝ in., with an inner rim diameter of 4⅜ in. and a maximum diameter of 7⅛ in.), of which nearly two-thirds has been restored, belongs to a class of samian ware that was first extensively studied by Déchelette. The decoration (fig. 1), consisting both of reliefs applied from a mould and of barbotine designs, is divided into three zones which are in turn separated from one another by double grooves of varying width.