Criação de zonas de alta permeabilidade em fraturas: modelagem numérica do Lajedo de Soledade, Formação Jandaíra, Bacia Potiguar

The fracturing in carbonate rocks has been attracting increasingly attention due to new oil discoveries in carbonate reservoirs. This study investigates how the fractures (faults and joints) behave when subjected to different stress fields and how their behavior may be associated with the generation of karst and consequently to increased secondary porosity in these rocks. In this study I used satellite imagery and unmanned aerial vehicle UAV images and field data to identify and map faults and joints in a carbonate outcrop, which I consider a good analogue of carbonate reservoir. The outcrop comprises rocks of the Jandaíra Formation, Potiguar Basin. Field data were modeled using the TECTOS software, which uses finite element analysis for 2D fracture modeling. I identified three sets of fractures were identified: NS, EW and NW-SE. They correspond to faults that reactivate joint sets. The Ratio of Failure by Stress (RFS) represents stress concentration and how close the rock is to failure and reach the Mohr-Coulomb envelopment. The results indicate that the tectonic stresses are concentrated in preferred structural zones, which are ideal places for carbonate dissolution. Dissolution was observed along sedimentary bedding and fractures throughout the outcrop. However, I observed that the highest values of RFS occur in fracture intersections and terminations. These are site of karst concentration. I finally suggest that there is a relationship between stress concentration and location of karst dissolution in carbonate rocks.

Criação de zonas de alta permeabilidade em fraturas: modelagem numérica do Lajedo de Soledade, Formação Jandaíra, Bacia Potiguar

The fracturing in carbonate rocks has been attracting increasingly attention due to new oil discoveries in carbonate reservoirs. This study investigates how the fractures (faults and joints) behave when subjected to different stress fields and how their behavior may be associated with the generation of karst and consequently to increased secondary porosity in these rocks. In this study I used satellite imagery and unmanned aerial vehicle UAV images and field data to identify and map faults and joints in a carbonate outcrop, which I consider a good analogue of carbonate reservoir. The outcrop comprises rocks of the Jandaíra Formation, Potiguar Basin. Field data were modeled using the TECTOS software, which uses finite element analysis for 2D fracture modeling. I identified three sets of fractures were identified: NS, EW and NW-SE. They correspond to faults that reactivate joint sets. The Ratio of Failure by Stress (RFS) represents stress concentration and how close the rock is to failure and reach the Mohr-Coulomb envelopment. The results indicate that the tectonic stresses are concentrated in preferred structural zones, which are ideal places for carbonate dissolution. Dissolution was observed along sedimentary bedding and fractures throughout the outcrop. However, I observed that the highest values of RFS occur in fracture intersections and terminations. These are site of karst concentration. I finally suggest that there is a relationship between stress concentration and location of karst dissolution in carbonate rocks.

Ichnology and palaeobiology of Phoebichnus trochoides and Schaubcylindrichnus heberti comb. nov.

The three-dimensional reconstructions of Phoebichnus trochoides and Schaubcylindrichnus (Palaeophycus) heberti created as part of this thesis allow us to fully understand and characterize the three-dimensional morphology and palaeobiology of these common taxa. Three-dimensional reconstructions demonstrate that P. trochoides is a large stellate burrow composed of numerous long galleries produced by a deposit feeding organism. This study reports for the first time that the central zone is composed of stacked disk-shaped layers of highly bioturbated sediment, the radial burrows are composed of a sand-rich lining of pelleted annuli surrounding an active sand-rich fill, and the presence of subtle conical features above the radial galleries that are inferred to result from collapse cone feeding. Reconstructions of heberti demonstrate that the thick walled burrows are composed of sand-rich annular rings, are a broad U-shape, and may be either clustered or isolated. Our observations show that the morphology of heberti is inconsistent with the generic diagnosis of Palaeophycus, but is morphologically comparable to Schaubcylindrichnus, and is herein synonymised with Schaubcylindrichnus to create S. heberti comb. nov. The three-dimensional reconstructions have revealed a number of hitherto unknown morphological elements to both taxa which has facilitated new interpretations of the trace-makers behaviour. The data improves the taxonomic understanding of both P. trochoides and S. heberti which require significant taxonomic change and emendation of diagnoses at the species and genus level.

Experimental investigation of water, snow and granular ice effects on ice failure processes and impact loads

A large series of laboratory ice crushing experiments was performed to investigate the effects of external boundary condition and indenter contact geometry on ice load magnitude under crushing conditions. Four boundary conditions were considered: dry cases, submerged cases, and cases with the presence of snow and granular ice material on the indenter surface. Indenter geometries were a flat plate, wedge shaped indenter, (reverse) conical indenter, and spherical indenter. These were impacted with artificially produced ice specimens of conical shape with 20° and 30° cone angles. All indenter – ice combinations were tested in dry and submerged environments at 1 mm/s and 100 mm/s indentation rates. Additional tests with the flat indentation plate were conducted at 10 mm/s impact velocity and a subset of scenarios with snow and granular ice material was evaluated. The tests were performed using a material testing system (MTS) machine located inside a cold room at an ambient temperature of - 7°C. Data acquisition comprised time, vertical force, and displacement. In several tests with the flat plate and wedge shaped indenter, supplementary information on local pressure patterns and contact area were obtained using tactile pressure sensors. All tests were recorded with a high speed video camera and still photos were taken before and after each test. Thin sections were taken of some specimens as well. Ice loads were found to strongly depend on contact condition, interrelated with pre-existing confinement and indentation rate. Submergence yielded higher forces, especially at the high indentation rate. This was very evident for the flat indentation plate and spherical indenter, and with restrictions for the wedge shaped indenter. No indication was found for the conical indenter. For the conical indenter it was concluded that the structural restriction due to the indenter geometry was dominating. The working surface for the water to act was not sufficient to influence the failure processes and associated ice loads. The presence of snow and granular ice significantly increased the forces at the low indentation rate (with the flat indentation plate) that were higher compared to submerged cases and far above the dry contact condition. Contact area measurements revealed a correlation of higher forces with a concurrent increase in actual contact area that depended on the respective boundary condition. In submergence, ice debris constitution was changed; ice extrusion, as well as crack development and propagation were impeded. Snow and granular ice seemed to provide additional material sources for establishing larger contact areas. The dry contact condition generally had the smallest real contact area, as well as the lowest forces. The comparison of nominal and measured contact areas revealed distinct deviations. The incorporation of those differences in contact process pressures-area relationships indicated that the overall process pressure was not substantially affected by the increased loads.

Comportamento mecânico e biológico de implante dentário com interface cônica interna

The general aim of this study was to evaluate the conical interface of pilar/implant. The specific aims were to evaluate the influence of hexagonal internal index in the microleakage and mechanical strength of Morse taper implants; the effect of axial loading on the deformation in cervical region of Morse taper implants of different diameters through strain gauge; the effect of axial loading in cervical deformation and sliding of abutment into the implant by tridimensional measurements; the integrity of conical interface before and after dynamic loading by microscopy and microleakage; and the stress distribution in tridimensional finite element models of Morse taper implants assembled with 2 pieces abutment. According to the obtained results, could be concluded that the diameter had influence in the cervical deformation of Morse taper implants; the presence of internal hexagonal index in the end of internal cone of implant didn´t influenced the bacterial microleakage under static loading neither reduced the mechanical strength of implants; one million cycles of vertical and off-center load had no negative influence in Morse taper implant integrity.

The Timing of Motherhood While Earning a PhD in Engineering

In spite of tremendous efforts, women are still under-represented in the field of science. Post-graduate education and early tenure track employment are part of the academic career establish-ment in research and development during periods that usually overlap with family formation. Though women tend to leave science mainly after obtaining their PhD, and the timing of mother-hood plays a vital role in a successful research career, qualitative data on this life period are scarce. Our paper focuses on how the normative and institutional contexts shape female PhD engineering students’ family plans. The research was based on intersections of life course and risk and uncertainty theories. Using qualitative interviews we explored how contradicting social norms of childbearing cause tensions in postgraduate students’ lives, and how the different uncer-tainties and risks permeate young researchers’ decisions on early life events. We concluded that, despite the general pattern of delaying motherhood among higher educated women, these students struggle against this postponement, and they hardly have any good options to avoid risk stem-ming from uncertainties and from some characteris-tics of studying and working in engineering. Find-ings of this research may call the attention of stake-holders to possible intervention points.

Work-life Balance and Gender Regime After the Economic Transition

Work-life balance (WLB) is a key issue in our societies in which there is increasing pressure to be permanently available on demand and to work more intensively, and when due to technological change the borders between work and private life appear to be dissolving. However, the social, institutional and normative frames of a region have a huge impact on how people experience work and private life, where the borders between these spheres lie and how much control individuals have in managing these borders. Based on these arguments, this editorial to the special issue Work-life balance/imbalance: individual, organisational and social experiences in Intersections. EEJSP draws attention to the social institutions, frameworks and norms which have an effect on experience, practices and expectations about work-life balance. Concerning the time horizon, this editorial focuses on the change of regime as a reference point since socialist and post-socialist eras differ significantly, although there is still some continuity between them. The authors of this introduction offer an overview of the situation in CEE (Central and Eastern Europe) based mainly on examples of Visegrad countries.

Globalizing the Sculptural Landscapes of the Sarapis and Isis Cults in Hellenistic and Roman Greece

“Globalizing the Sculptural Landscape of Isis and Sarapis Cults in Roman Greece,” asks questions of cross-cultural exchange and viewership of sculptural assemblages set up in sanctuaries to the Egyptian gods. Focusing on cognitive dissonance, cultural imagining, and manipulations of time and space, I theorize ancient globalization as a set of loosely related processes that shifted a community's connections with place. My case studies range from the 3rd century BCE to the 2nd century CE, including sanctuaries at Rhodes, Thessaloniki, Dion, Marathon, Gortyna, and Delos. At these sites, devotees combined mainstream Greco-Roman sculptures, Egyptian imports, and locally produced imitations of Egyptian artifacts. In the last case, local sculptors represented Egyptian subjects with Greco-Roman naturalistic styles, creating an exoticized visual ideal that had both local and global resonance. My dissertation argues that the sculptural assemblages set up in Egyptian sanctuaries allowed each community to construct complex narratives about the nature of the Egyptian gods. Further, these images participated in a form of globalization that motivated local communities to adopt foreign gods and reinterpret them to suit local needs.

I begin my dissertation by examining how Isis and Sarapis were represented in Greece. My first chapter focuses on single statues of Egyptian gods, describing their iconographies and stylistic tendencies through examples from Corinth and Gortyna. By comparing Greek examples with images of Sarapis, Isis, and Harpokrates from around the Mediterranean, I demonstrate that Greek communities relied on globally available visual tropes rather than creating site or region-specific interpretations. In the next section, I examine what other sources viewers drew upon to inform their experiences of Egyptian sculpture. In Chapter 3, I survey the textual evidence for Isiac cult practice in Greece as a way to reconstruct devotees’ expectations of sculptures in sanctuary contexts. At the core of this analysis are Apuleius’ Metamorphoses and Plutarch’s De Iside et Osiride, which offer a Greek perspective on the cult’s theology. These literary works rely on a tradition of aretalogical inscriptions—long hymns produced from roughly the late 4th century B.C.E. into the 4th century C.E. that describe the expansive syncretistic powers of Isis, Sarapis, and Harpokrates. This chapter argues that the textual evidence suggests that devotees may have expected their images to be especially miraculous and likely to intervene on their behalf, particularly when involved in ritual activity inside the sanctuary.

In the final two chapters, I consider sculptural programs and ritual activity in concert with sanctuary architecture. My fourth chapter focuses on sanctuaries where large amounts of sculpture were found in underground water crypts: Thessaloniki and Rhodes. These groups of statues can be connected to a particular sanctuary space, but their precise display contexts are not known. By reading these images together, I argue that local communities used these globally available images to construct new interpretations of these gods, ones that explored the complex intersections of Egyptian, Greek, and Roman identities in a globalized Mediterranean. My final chapter explores the Egyptian sanctuary at Marathon, a site where exceptional preservation allows us to study how viewers would have experienced images in architectural space. Using the Isiac visuality established in Chapter 3, I reconstruct the viewer's experience, arguing that the patron, Herodes Atticus, intended his viewer to inform his experience with the complex theology of Middle Platonism and prevailing elite attitudes about Roman imperialism.

Throughout my dissertation, I diverge from traditional approaches to culture change that center on the concepts of Romanization and identity. In order to access local experiences of globalization, I examine viewership on a micro-scale. I argue that viewers brought their concerns about culture change into dialogue with elements of cult, social status, art, and text to create new interpretations of Roman sculpture sensitive to the challenges of a highly connected Mediterranean world. In turn, these transcultural perspectives motivated Isiac devotees to create assemblages that combined elements from multiple cultures. These expansive attitudes also inspired Isiac devotees to commission exoticized images that brought together disparate cultures and styles in an eclectic manner that mirrored the haphazard way that travel brought change to the Mediterranean world. My dissertation thus offers a more theoretically rigorous way of modeling culture change in antiquity that recognizes local communities’ agency in producing their cultural landscapes, reconciling some of the problems of scale that have plagued earlier approaches to provincial Roman art.

These case studies demonstrate that cultural anxieties played a key role in how viewers experienced artistic imagery in the Hellenistic and Roman Mediterranean. This dissertation thus offers a new component in our understanding of ancient visuality, and, in turn, a better way to analyze how local communities dealt with the rise of connectivity and globalization.

Collimation of a D-D Neutron Generator for Clinical Implementation of Neutron Stimulated Emission Computed Tomography: a Monte Carlo Study

This work is an investigation into collimator designs for a deuterium-deuterium (DD) neutron generator for an inexpensive and compact neutron imaging system that can be implemented in a hospital. The envisioned application is for a spectroscopic imaging technique called neutron stimulated emission computed tomography (NSECT).

Previous NSECT studies have been performed using a Van-de-Graaff accelerator at the Triangle Universities Nuclear Laboratory (TUNL) in Duke University. This facility has provided invaluable research into the development of NSECT. To transition the current imaging method into a clinically feasible system, there is a need for a high-intensity fast neutron source that can produce collimated beams. The DD neutron generator from Adelphi Technologies Inc. is being explored as a possible candidate to provide the uncollimated neutrons. This DD generator is a compact source that produces 2.5 MeV fast neutrons with intensities of 1012 n/s (4π). The neutron energy is sufficient to excite most isotopes of interest in the body with the exception of carbon and oxygen. However, a special collimator is needed to collimate the 4π neutron emission into a narrow beam. This work describes the development and evaluation of a series of collimator designs to collimate the DD generator for narrow beams suitable for NSECT imaging.

A neutron collimator made of high-density polyethylene (HDPE) and lead was modeled and simulated using the GEANT4 toolkit. The collimator was designed as a 52 x 52 x 52 cm3 HDPE block coupled with 1 cm lead shielding. Non-tapering (cylindrical) and tapering (conical) opening designs were modeled into the collimator to permit passage of neutrons. The shape, size, and geometry of the aperture were varied to assess the effects on the collimated neutron beam. Parameters varied were: inlet diameter (1-5 cm), outlet diameter (1-5 cm), aperture diameter (0.5-1.5 cm), and aperture placement (13-39 cm). For each combination of collimator parameters, the spatial and energy distributions of neutrons and gammas were tracked and analyzed to determine three performance parameters: neutron beam-width, primary neutron flux, and the output quality. To evaluate these parameters, the simulated neutron beams are then regenerated for a NSECT breast scan. Scan involved a realistic breast lesion implanted into an anthropomorphic female phantom.

This work indicates potential for collimating and shielding a DD neutron generator for use in a clinical NSECT system. The proposed collimator designs produced a well-collimated neutron beam that can be used for NSECT breast imaging. The aperture diameter showed a strong correlation to the beam-width, where the collimated neutron beam-width was about 10% larger than the physical aperture diameter. In addition, a collimator opening consisting of a tapering inlet and cylindrical outlet allowed greater neutron throughput when compared to a simple cylindrical opening. The tapering inlet design can allow additional neutron throughput when the neck is placed farther from the source. On the other hand, the tapering designs also decrease output quality (i.e. increase in stray neutrons outside the primary collimated beam). All collimators are cataloged in measures of beam-width, neutron flux, and output quality. For a particular NSECT application, an optimal choice should be based on the collimator specifications listed in this work.

(Table 1) Strontium isotopic ratios of interstitial waters from ODP Leg 125 holes

The strontium isotopic data presented here are from interstitial waters squeezed from unconsolidated serpentine, an unusual type of substrate that was recovered from Mariana and Bonin forearc seamounts and has not been previously drilled by the Deep Sea Drilling Project or Ocean Drilling Program. The texture and composition of some of these serpentine deposits from Conical Seamount, located on the Mariana forearc, indicate emplacement as low- or high-viscosity, cold gravitational flows, which are therefore neither sediment nor igneous rock. The strontium isotopic ratios of the interstitial waters from the unconsolidated serpentine range from 0.70912 to 0.70525 and trend toward a relatively less radiogenic composition with increasing sub-bottom depth. These strontium isotopic ratios are derived from at least two strontium sources: seawater and igneous. The strontium isotopic gradients from the interstitial waters from the Leg 125 sites are probably the result of diffusive transport of strontium from an igneous source deep within the lithosphere that may be contaminated with subducted or underplated sediment.

(Table 1) Composition of interstitial waters from ODP Leg 125 sites

Pore waters were collected from nine sites during Leg 125 of the Ocean Drilling Program (ODP). The first four sites (778-781) were drilled in the Mariana forearc on and near Conical Seamount, an active serpentine "mud volcano" located about 80 km behind the trench axis and 120 km in front of the active island arc. The last five sites (782-786) were drilled in the Izu-Bonin forearc between the trench and the outer arc high. Pore waters from the five sites from both areas that penetrated serpentine silts (Sites 778,779,780,783, and 784) are discussed in detail by Mottl (this volume). Here we report analyses of the pore waters from all nine sites for Li, Rb, Sr, Ba, Mn, B, and the sulfur isotopic ratio of dissolved sulfate. Sampling methods and results of analyses for major and minor species determined aboard ship were presented by Fryer, Pearce, Stokking, et al. (1990, doi:10.2973/odp.proc.ir.125.1990).

Biogeochemical properties of sinking particles intercepted at three depths on the NW Atlantic margin

Three conical sediment were deployed at three depths 968 m (top trap), 1976 m (middletrap), and 2938 m (50mabove the bottom, bottom trap) - from June 27, 2004 to April 27, 2005 on the NW Atlantic margin at a water depth of 2988 m. The sediment trap carousels were programmed to open each collection cup for 23.4 days for the top trap and 14.5 days for the other two traps, resulting in total 13 samples from the top trap and 21 samples each from the middle and bottom traps. The samples were analyzed for the biogeochemical properties with various methods. Frequent occurrences of higher fluxes in deep relative to shallower sediment traps and low delta 14C values of sinking POC together provide strong evidence for significant lateral transport of aged organic matter over the margin. Comparison of biogeochemical properties such as aluminum concentration and flux, and iron concentration between samples intercepted at different depths shows that particles collected by the deepest trap had more complex sources than the shallower ones. These data also suggest that at least two modes of lateral transport exist over the New England margin. Based on radio carbon mass balance, about 30% (± 10%) of sinking POC in all sediment traps is estimated to be derived from lateral transport of re-suspended sediment. A strong correlation between delta 14C values and aluminum concentrations suggests that the aged organic matter is associated with lithogenic particles.

Feeling Bodies in Marketing: Aesthetics, Emotions and Gender

Gender is deeply embedded in marketing ideology, and it continues to be a topic of concern in the marketing academy. There is little attention paid by marketers, however, to related studies in other fields on aesthetic labour and emotional labour in relation to gender issues, despite the commonalities and intersections between them. This article seeks to incorporate aesthetic labour and emotional labour into the gender and marketing discussion. It concludes by calling for greater critical awareness of gender as a dominant motif in our ideologies, discourses and practices in marketing, offering suggestions for empirical research into this important topic.

Intersecting Whiteness: Interdisciplinary Debates

This article sets out the purview of this special issue of Ethnicities. Whiteness Studies has moved from the margins and has become an accepted focus for study in Critical Race Studies. We argue that current scholarship is developing the paradigm empirically and theoretically, and does so without need to justify its approach. This special issue incorporates a number of national and transnational contexts, is located in a number of disciplines and theoretical approaches, and develops the intersections between whiteness and gender, queer studies, migration, nationalism and militarization.

Queering Apartheid: The National Party’s 1987 ‘Gay Rights’ Election Campaign in Hillbrow

This article investigates the anomaly in apartheid history of the ruling National Party's (NP) fielding a ‘pro-gay rights’ candidate in the Hillbrow constituency during the 1987 whites-only election in South Africa. The NP was aided in its Hillbrow campaign by the gay magazine Exit, which encouraged its readership to ‘vote gay’ in the election and published a list of candidates who were favourable to gay rights in South Africa. The Hillbrow campaign is intelligible when the intersections between race and sexuality are analysed and the discourses wielded by the NP and Exit are spatially and historically situated. The Hillbrow/Exit gay rights campaign articulated discourses about the reform of apartheid in white self-interest and conflated white minority and gay minority rights, thereby contributing to the NP's justification for apartheid. The NP candidate's defeat of the incumbent Progressive Federal Party (PFP) MP for Hillbrow, Alf Widman, was trumpeted by Exit as a powerful victory and advance for gay rights in South Africa, but the result provoked a sharp backlash among many white gay men and lesbian women who organised to openly identify with the liberation movement. The Exit/Hillbrow campaign problematises the singular assumptions that are often made about race and sexuality in apartheid South Africa, and illustrates how political, social and economic crisis can provoke reconfigurations of identities vis-à-vis the status quo.