Analysis of the types of Reinholdella, an important Jurassic foraminiferal genus

Experimental study on crack propagation characteristics of unconventional reservoir rocks

The monotypic genus Riveroinella was erected by Bermudez and Seiglie in 1967 as belonging to the family Ceratobuliminidae, a group of benthonic foraminifera characteristically having an aragonitic shell. Examination of its type species, R. martinezpicoi, reveals that the genus Riveroinella is a junior synonym of the planktonic foraminiferal genus Cassigerinella Pokorny, 1955, not only because R. martinezpicoi has an enrolled biserial coil in the last whorl, but also because the shell of R. martinezpicoi is calcitic, not aragonitic as claimed in the original description. A detailed morphologic examination of the type species of the genus Cassigerinella, C. chipolensis (Cushman and Ponton), was made with the use of a scanning electron microscope (SEM), because some authors have assigned this species to the benthonic foraminiferal family Cassidulinidae in the belief that C. chipolensis has an internal tooth plate. Our SEM examination indicates that Cassigerinella possesses no tooth plate, but instead a distinct rimlike protruding apertural flange. Therefore, the genus is herein retained in the planktonic foraminiferal family Hantkeninidae. INTRODUCTION Bermudez and Seiglie (1967) erected the monotypic foraminiferal genus Riveroinella, with type species Riveroinella martinezpicoi, placing it in the family Ceratobuliminidae because they believed its shell to be made of aragonite. While studying the foraminifera from JOIDES Hole 3 on the Blake Plateau off northern Florida (Bunce et al., 1965), the senior author observed an apparently new species of Cassigerinella, associated with Globigerinoides sicanus de Stefani, Globorotalia peripheroronda Banner and Blow, and Praeorbulina glomerosa (Blow). In describing planktonic foraminifera recovered during DSDP (Deep Sea Drilling Project) Leg 34 from the eastern Pacific Ocean, Quilty (1 976, p. 651, pl. 19, figs. 13-14) figured a Cassigerinella closely resembling the Cassigerinella specimen that the senior author recognized from the Blake Plateau. In general morphology, both of these specimens of Cassigerinella are closely comparable with Riveroinella martinezpicoi Bermudez and Seiglie, and the question was posed as to whether R. martinezpicoi is indeed an independent genus characterized by a planispiral test and an aragonitic shell, as was originally contended by Bermudez and Seiglie (1967). Examination of the holotype (USNM 687203) and two paratypes (687204, 687205), on loan from the United States National Mseum of Natural History in Washington, D. C., indicates that the specimen from the Blake Plateau is taxonomically identical with the type specimens of R. martinezpicoi and that chambers in the last whorl of R. martinezpicoi are arranged in an enrolled biserial coil in the manner characteristic of the genus Cassigerinella (text-figure 1). The purpose of this paper is to demonstrate that Riveroinella is a junior synonym of Cassigerinella, not only because its type species has an enrolled biserial coil in the last whorl, but also because the shell of R. martinezpicoi is calcitic, not aragonitic as claimed in the original description given by BermOdez and Seiglie in 1967. SYSTEMATIC PALEONTOLOGY Superfamily GLOBIGERINACEA Carpenter, Parker and Jones, 1862 Family HANTKENINIDAE, Cushman, 1927 Subfamily CASSIGERINELLINAE Bolli, Loeblich and Tappan, 1957 Genus Cassigerinella Pokorny, 1955 Discussion: In the original description, Pokorny (1955) suggested merely that the genus Cassigerinella is closely related to the genus Globigerinella. Bolli, Loeblich and Tappan (1957) were the first to assign Cassigerinella to the superfamily Globigerinacea, which includes only taxa having a planktonic mode of life. This assignment has been micropaleontology, vol. 23, no. 3, pp. 319-329, pls. 1-2, july, 1977 319 This content downloaded from 207.46.13.51 on Tue, 21 Jun 2016 06:55:29 UTC All use subject to http://about.jstor.org/terms

Fatigue crack growth rate in axial, torsional and multiaxial mode in 316L austenitic steel

The present research reassesses the taxonomic position of species of Leptosphaeria described from plants in the family Rosaceae. In doing so, this wori< emphasizes a concept of Leptosphaeria based on its type species. Because discrete groups of morphologically similar species were found on related hosts (Nixlulosphaeria on Compositae, Phaeosphaeria on Gramineae and Entodesmiitm on Leguminosae), a goal of the study was to determine whether a distinct group of related species could be found on Rosaceous hosts. Also, approaching the taxonomy of this large, complex genus on the basis of host family is a convenient way of dividing the large numbers of Leptosphaeria species into smaller, workable groups.
 Fifty-five species described from Rosaceous hosts have been included in Leptosphaeria (see appendix). Efforts were made to locate and obtain type material for all of the described species. The names of herbaria providing material are abbreviated in this dissertation according to Index Herbariorum (Holmgren et al. 1990). Whenpossible, type specimens were studied, supplemented by other collections, and the species were redescribed and illustrated from the type material. Unfortunately, type material could not be located for all of the species; in such cases, descriptions were based on other material only when the resulting concept of the species was obviously in accordance with the original description. From this work, it became apparent that no discrete group of related species is specialized on the Rosaceae. Thespecies studied were determined to represent a mixture of Loculoascomycetes and Hymenoascomycetes, and non-Leptosphaeria species were reassigned to more appropriate genera.

How does the choice of size metric, specimen selection, and taxonomic level affect the results of macroevolutionary or ecological analyses? Four molluscan data sets are used to address this question as follows. First, the relationships among various size metrics are examined using a morphometric data set of Late Cretaceous–Oligocene veneroid bivalves. Second, the relationship between the size of bulk-sampled specimens and the size of species' type specimens is examined using bulk-sampled bivalves and gastropods from the Coffee Sand (Upper Cretaceous, Mississippi). Third, the same relationship is examined using mollusk-dominated field censuses from the type Cincinnatian (Upper Ordovician, Ohio, Indiana, and Kentucky). Fourth, the relationship between the size of the type species of a genus and median species size is examined using literature-derived measurements of bivalve type specimens from the recent eastern Pacific continental shelf. Together these data sets provide estimates of the biases imposed by measuring different kinds of specimens and using different methods of estimating body size. The geometric mean of length and height is highly correlated with more complex morphometrically based metrics and is our preferred bivalve size metric. Bulk or randomly sampled specimens are significantly smaller than species' type specimens for the Cretaceous dataset but significantly larger for the Ordovician dataset. Genus' type-species size is an unbiased estimate of median species size. These results suggest that large-scale studies can use the size of the type species of a genus as an unbiased proxy for a type-specimen size of a genus' median species, but that species' type-specimen size is a biased proxy for bulk or randomly sampled specimens. In addition, this study emphasizes the importance of using a single type of measurement within studies and suggests that combining multiple types of specimens (e.g., type specimens and bulk-sampled specimens) could lead to substantive errors.

The scanning electron microscope is a relatively new instrument now finding rapidly growing use in the materials sciences. It scans a fine beam of electrons across the specimen surface and displays an image of that surface on a cathode-ray tube using any of the radiations that are generated by incident electrons. The characteristics of each of the images that can be formed using the different signals available are described, as well as its particular use for different types of specimens. Many types of materials specimens can be examined in the scanning electron microscope with no preparation, but to obtain optimum results it is often necessary or desirable to coat the surface with a thin conductive layer. This and other steps of specimen preparation and handling techniques for solid and powder samples are outlined. Finally the interpretation of the various types of images and the dynamic observation of changes produced in the specimen by heating, straining, etc., are considered.

We have developed a relatively rapid glutaraldehyde-tannic acid (GTA) and osmium tetroxide (OsO4) fixation procedure which permits many types of uncoated biological specimens to be examined in the scanning electron microscope (SEM) at 20 kV without the occurrence of charging. Most specimens taken one day can be examined in the SEM the following afternoon. Types of specimens successfully treated were perfused adult and embryonic rat tissues, confluent human skin fibroblast tissue cultures, plant roots, flowers, seeds, some garden insects, and microcolonies of salivary streptococci. Cells in suspension and extracted human teeth did become electron conductive when treated with the GTA procedure. Most suspended cells must be centrifuged between each solution and the GTA procedure increases the preparation time for these cells. Extracted teeth are usually simply dried and coated. Therefore, the usual SEM preparation techniques are shorter and perhaps more useful for these types of specimens.

Summary Several different types of materials have been evaluated for use in gravel packing high-temperature thermal wells. The materials include Ottawa sand, sand from Venezuela, resin-coated sand, sintered bauxite. and high-alumina beads. The materials were evaluated at various temperatums up to 600 deg. F (316 deg. C] and pH's ranging from 7.0 to 11.0. The tests were conducted by passing water in the fluid phase through samples of the various materials at the desired pH and temperature. Weight-loss measurements and visual inspection by a scanning electron microscope (SEM) were performed on each sample to determine the effect of the various temperatures and pH's. The steam evaluation of the various gravel-packing materials shows that the alumina-based materials are best suited for gravel packing thermal wells, where the temperature may reach 600 deg. F 1316 deg. C1 and the pH of the aqueous phase of the steam reaches 11.0. The alumina materials have very little weight loss and maintain a uniform shape. Quartz materials show dramatic weight losses as temperature and pH increase. The weight loss of resincoated sand is most affected by increasing pH al elevated temperatures. Introduction Steamflooding and stimulation by steam are two of the most widely used methods for the production of heavy crudes. Most thermal recovery operations are in formations that are classified as unconsolidated and that require some form of sand control. One accepted method of sand control is gravel packing the well with a highquality silica sand or other suitable materials, such as sintered bauxite or resin-coated sand. Shallow wells generally are stimulated with steam injection at moderate rates and temperatures under 450 deg. F [232 deg. C]. Deeper wells, however, may require steam at temperatures higher than 600 deg. F [316 deg. C to be injected at the wellhead. This high-temperature steam is required to ensure that enough heat is transmitted to the formation in the deep wells to allow for efficient recovery of the heavy crudes. It is well established that the solubility of quartz sand and other siliceous materials in water increases sharply at high temperatures and pH's (see Fig. 1). Because of the composition of certain feedwaters used for steam generation, the liquid phase of the injected steam can have a relatively high pH. Where high pH and high temperatures are observed, gravel packs composed of quartz sand can be relatively short-lived. Steam Evaluation of Gravel-Pack Materials Several different types of common gravel-pack materials were evaluated. Two sources of gravel-pack sand were tested to determine whether differences in quartz content were important to the stability of quartz at elevated pH and temperature. Ottawa sand, which contains 99.9% quartz, and a sand from Venezuela, which contains 95 % quartz and various amounts of impurities (such as feldspar goethic, kaolinite, chlorite, and illite), were as subjected to various temperatures up to 600 deg. F [316 deg. C and pH's up to 11.0. Two types of bauxitic materials were chosen for evaluation. The first material was the sintered bauxite commonly used as a high-strength fracture proppant. The second sintered-bauxite-type material is a byproduct of a manufacturing process and contains more A1203 than the more common fracture proppant. Table 1 shows a comparison of the properties of the two sintered materials. Sintered bauxite and high-alumina beads are very stable in high-temperature/dry-heat environments, as shown in Table 2. Terns at thermal-well conditions of temperature and pH were performed to determine whether the differences in the amount of A1203 of the two bauxitic materials would result in greater stability. The use of resin-coated sand to control sand in thermal wells has been growing in popularity over the past several years. Improvements in resin chemistry and manufacturing processes have helped to increase the thermal stability of this type of material and to prolong its effectiveness in the harsh environment of steam-recovery wells. Tests were performed to determine the stability of one such material as a function of pH and temperature. Effect of Feedwater Many of the waters used to produce steam for thermal recovery projects contain HCO-3. This material is found in the formation feedwater and is not removed during the softening treatment before injection into the steam generator. Thermal degradation of the HCO - ions in the feed-water results in CO2 and OH - . Because most steam generators in the field produce 80% steam, the OH ions remain dissolved in the aqueous phase of the steam and produce a very alkaline solution depending on the concentration of HCO - in the feedwater. JPT P. 2006^

Health and environmental impacts of graphene-based materials need to be thoroughly evaluated before their potential applications. Graphene has strong cytotoxicity toward bacteria. To better understand its antimicrobial mechanism, we compared the antibacterial activity of four types of graphene-based materials (graphite (Gt), graphite oxide (GtO), graphene oxide (GO), and reduced graphene oxide (rGO)) toward a bacterial model-Escherichia coli. Under similar concentration and incubation conditions, GO dispersion shows the highest antibacterial activity, sequentially followed by rGO, Gt, and GtO. Scanning electron microscope (SEM) and dynamic light scattering analyses show that GO aggregates have the smallest average size among the four types of materials. SEM images display that the direct contacts with graphene nanosheets disrupt cell membrane. No superoxide anion (O(2)(•-)) induced reactive oxygen species (ROS) production is detected. However, the four types of materials can oxidize glutathione, which serves as redox state mediator in bacteria. Conductive rGO and Gt have higher oxidation capacities than insulating GO and GtO. Results suggest that antimicrobial actions are contributed by both membrane and oxidation stress. We propose that a three-step antimicrobial mechanism, previously used for carbon nanotubes, is applicable to graphene-based materials. It includes initial cell deposition on graphene-based materials, membrane stress caused by direct contact with sharp nanosheets, and the ensuing superoxide anion-independent oxidation. We envision that physicochemical properties of graphene-based materials, such as density of functional groups, size, and conductivity, can be precisely tailored to either reducing their health and environmental risks or increasing their application potentials.

Mechanical behavior and characteristics of two different types of materials: cast iron with lamellar graphite EN-GJL-250 and cast iron with spheroidal graphite EN-GJS-400-15 which were cast in ceramic molds using gravitational casting method has considered in this research. The ceramic molds were obtained by 3D printing method. First, a finite element analysis was developed to determine Tresca and von Mises stresses and the deformations of the ceramic molds under an applied pressure of 25 MPa. Samples were produced by gravitational casting using two types of cast iron materials. Mechanical tests were made using samples produced from these two types of materials and microstructure analysis evaluation of fractured zones was realized by scanning electron microscopy. Obtained results were finally used for designing, developing, and producing of one ‘hydraulic block’ of a railway installation by the Benninger Guss company of Switzerland.

The hydrozoan genus Zyzzyzus is revised based on reexaminations of all available type specimens and on additional material. The taxon includes four valid species: Zyzzyzus spongicolus (von Lendenfeld, 1884), from the eastern Indian and southwest Pacific oceans; the type species, Z. warreni Calder, 1988, from the Atlantic, western Indian, and western Pacific oceans; and Z. floridanus Petersen, 1990 and Z. robustus Petersen, 1990, both from the northwest Atlantic. Although type specimens of Z. calderi Petersen, 1990 could not be located, it has been assigned here to the synonymy of Z. warreni because of similarities between the two in nematocyst dimensions, in number and structure of endodermal canals, and in external morphology of the hydrocaulus and hydrorhiza. A sixth nominal species (Corymorpha iyoensis Yamada, 1958) has on one occasion been assigned to the genus, but detailed studies of the type material are needed to resolve its taxonomic affinities.

Studies on the generitype and Australian material of Tetrasporopsis (De Toni) Lemmermann are used to elucidate the concept of this genus. A specimen collected by A. Braun in 1846 is chosen as the lectotype for the type species, T. fuscescens (A. Braun ex Kützing) Lemmermann. Australian collections closely matched the type material and could be examined in more detail. Both the Australian and type specimens have cell walls, chloroplasts with girdle lamellae, chloroplast lamellae with three adpressed thylakoids, and mitochondria with tubular cristae. Contractile vacuoles were not observed in living Australian material. Centrioles were also present, but flagella and zoospores were not observed; no microtubules were preserved in the type material. A new genus, Dermatochrysis gen. nov., is proposed for colonial monostromatic algae belonging to the Chrysophyceae that lack cell walls and contain contractile vacuoles. Three species are transferred from Tetrasporopsis to Dermatochrysis: D. reticulata (Meyer) comb. nov., the type species; D. pseudofenestrata (Lund) comb. nov. and D. pelagica (R.E. Norris) comb. nov. The relationship of Dermatochrysis to Tetrasporopsis and other capsoid and coccoid genera is discussed.

In order to examine the initiation mechanism of delamination in ultrahigh molecular weight polyethylene (UHMWPE) knee components, a bi-directional sliding fatigue test was performed for three types of UHMWPE specimens: nonirradiated, gamma-irradiated (25 kGy) and gamma-irradiated (25 kGy) with 0.1% vitamin E added. Sliding surfaces of post-tested UHMWPE specimens were observed using an optical microscope and a scanning electron microscope. Also, surface roughness was measured at the sliding surfaces of UHMWPE specimens. Delamination was observed only in gamma-irradiated specimens. A networked structure of surface asperity that resembled grain boundary was observed prior to delamination in gamma-irradiated specimens. Surface roughness in the gamma-irradiated specimens, higher than in any other specimen, showed a rapid increase prior to delamination. Detailed observation using an optical microscope and a scanning electron microscope showed microscopic crack initiation along subsurface grain boundaries in gamma-irradiated specimens. These results suggest that subsurface crack initiation is a precursor of delamination and is accelerated by oxidative degradation due to gamma irradiation. Of the three types of specimens, UHMWPE with vitamin E added showed the lowest surface roughness values at all measuring points. The addition of vitamin E is effective in improving wear resistance and fatigue performance of UHMWPE.

The type specimens of 42 cheilostome bryozoan species introduced by Lars Siln between 1938 and 1954 and housed at three different Swedish institutions (the Swedish Museum of Natural History in Stockholm, the Biological Museum in Lund and the Museum of Evolution in Uppsala) are here revised using scanning electron microscopy, with two exceptions, for the first time. As a result of this revision, new morphological observations were made for some species, such as ooecia in Antropora erecta, a costal pseudopore in Jullienula hippocrepis, intracolonial variation in the number of intracostal windows in Costaticella gisleni, and oral spines in Triphyllozoon mauritzoni. Some other observations confirmed the presence of structures/polymorphs in type material that had previously only been noted in non-type specimens, such as spinose interzooidal kenozooids in Retevirgula triangulata and putative brooding zooids in Bugulina kiuschiuensis. Structures originally interpreted as hydroid tube openings on the dorsal side of Triphyllozoon microstigmatum were confirmed to be avicularia, while the supposed kenozooidal attachment rootlet of Fedora nodosa might be the polypide tube of a coronate scyphozoan. In addition, the original combination Heliodoma goesi is here reinstated after Lagaaij assigned the species to Setosellina in 1963. The following new combinations are also proposed: Labioporella aviculifera for Siphonoporella aviculifera; Mangana canui and Mangana incrustata for Callopora canui and Tegella incrustata, respectively; Sphaerulobryozoon ovum for Fedora ovum. Lectotypes were selected when appropriate. This work clarifies the exact identity of some species that have never been recorded after their first description, such as Stylopoma magnovicellata and three species of Triphyllozoon, and contributes to the current increasing effort to digitize historical key specimens in natural history museum collections.

The type species (Spiniloculus mavensis Southwell, 1925) of the previously monotypic tetraphyllidean genus Spiniloculus Southwell, 1925 is redescribed from the type material from Moreton Bay, Australia. As a consequence the identity of this species is definitively resolved. Three new species in the genus, all collected from Chiloscyllium punctatum Müller et Henle (brownbanded bambooshark), in Borneo, are described. Spiniloculus calhouni sp. n. conspicuously differs from all three of its congeners in its possession of post-poral testes. Spiniloculus fylerae sp. n. and Spiniloculus paigeae sp. n. differ from their two other congeners in that they are relatively small worms (4-6.5 and 2.2-5 mm in total length, respectively) with fewer than 30 proglottids. They can be distinguished from one another in that, while the vitelline follicles are interrupted at the level of its ovary in S. fylerae, this is not the case in S. paigeae. Furthermore, whereas the cirrus sac of the former species is pyriform, it is elongate-oval in the latter species. This brings the total number of species in the genus to four, and lends support to the suggestion that the original identity of the type host of S. mavensis as Mustelus sp. was in error. This work also extends the range of the genus to include the island of Borneo. A key to the species of Spiniloculus is provided. Morphological data generated here, using both light and scanning electron microscopy, support the suggested close affinities between Spiniloculus and Yorkeria Southwell, 1927, both of which parasitize bamboosharks.