bluuebunny/crossref_metadata_2025 huggingface dataset:
Real-Time Downhole Monitoring Of Hydraulic Fracturing Treatments Using Fibre Optic Distributed Temperature and Acoustic Sensing
Authors: Molenaar Mathieu M. , Fidan Erkan , Hill David J.
Published: March 2012

In order to make commercial and development decisions effectively and more rapidly, new appraisal and testing technologies are needed to maximize early data collection and subsequent subsurface understanding as quickly as possible. For Unconventional Gas and Light Tight Oil (UGLTO) projects, some of this critical data can be derived from hydraulic fracture stimulation and inflow profiling activities.

For UGLTO projects, achieving an optimum hydraulic fracture stimulation is a continuous endeavor beginning as early as possible; and balancing the cost of completion vs. production performance is critical as the completion/stimulation is a large cost component of the well and heavily influences production rate/ultimate recovery. The fast paced development and introduction of new completion technologies requires diagnostic technology that can help us understand stimulation effectiveness, assess new completion technologies, and evaluate which zones are the most productive.

One emerging technology, fibre optic distributed sensing has the potential of providing key insights during both the hydraulic fracturing and initial flowback. The passive nature of fibre optic sensors allows intervention-free surveillance, which makes fibre-optic technology an effective platform for permanent sensing in producing wells. Until recently, the oil & gas industry fibre optic sensing technology has focused mainly on temperature (DTS) profiling along the wellbore. In 2009, it was first demonstrated how fibre optic distributed acoustic sensing (DAS) can also be used for downhole applications. Where hydraulic fracture diagnostics based on DTS alone in the past sometimes yielded ambiguous results, the combination of both acoustic and temperature sensing provides a step-change improvement in the ability to perform real-time and post-job diagnostics & analyses of the stimulation.

The different horizontal well case studies presented in this paper will illustrate how the combination of DTS and DAS has the potential to enhance the monitoring, assessment, and optimization of openhole and limited entry designed hydraulic fracture stimulation treatments.
Study of Class G Cement Fatigue using Experimental Investigations
Authors: Kosinowski Christian , Teodoriu Catalin
Published: March 2012

This paper presents the results of laboratory investigation about fatigue of Class G wellbore cement exposed to radial loads under room temperature conditions.

While fatigue is well described for metals, wellbore cement fatigue is a rather unknown field. As well cements can be exposed to cyclic loading situations like in new oilfield technologies e.g. enhanced oil recovery by steam injection or geothermal applications using single-well-solutions, cement damage by fatigue becomes a more important issue. Cement integrity is crucial environmental and economic issue and no risk on cement failure should be accepted. The thermal induced loads in the reality were replaced by mechanical loads that recreates the stress situation on the cement. In order to evaluate the behavior of the cement, experiments were performed to investigate how cement reacts to cyclic loadings. A low number of cycles mean up to 100 loadings sequences. Samples of a pipe-cement-compound recreating the wellbore geometry are tested in a hydraulic press under axial loads. The stress situation in the cement sheath of the tested samples was calculated using a combination of numerical and analytical methods. Failure criteria were used to evaluate these calculations and could be used to predict future failure behavior. It has been found that fatigue of cement is rather similar for metal and cement at least in the low cycle range. For metals there is a specific stress limit where failure or significant damage to the material occurs within several cycles. This means, if the limit is exceeded the material will fail, maybe not at the first cycle, but it will fail over the cycles. Cement shows that this behavior is similar to metals, no other fatigue mechanisms like damage accumulation were observed, just a straight load limit.
Lessons Learned from North America and Current Status of Unconventional Gas Exploration and Exploitation in China
Authors: Ping Wang , Jiang Ruizhong , Wang Shichao
Published: March 2012

Unconventional gas has been paid more and more attention since the successful exploration in North America, China is no exception. Effective exploitation of unconventional gas can guarantee energy security, optimize energy structure and help protect environment in China.

Successful experiences from North America are summarized, current status of unconventional gas in China is analyzed from three aspects: resources, technologies, polices.

The success of North America profits from five reasons: governmental positive policies and tax preferences, advanced technologies, adequate pipeline infrastructure, small firms leading system, large demand of natural gas. China has large potential resources of unconventional gas. As to tight gas, the prospective resources of tight gas exceed 12 trillion cubic meters. For coal-bed methane(CBM), China is ranked 3rd after Russia and Canada and has 36.8 trillion cubic meters. China has just started shale gas study and has no definite evaluation. Until now, China has developed a series of technologies. For tight gas: high-precision 2D seismic, fast drilling, slim hole drilling. As for CBM: AVO response detect, penniform multi-lateral drilling and ultra-short radius jetting drilling. China has set many beneficial policies for unconventional gas especially for CBM, now the government is working hard on making positive policies and tax preferences for shale gas. There are several differences between North America and China: geological difference, land ownership, regulatory framework, pipeline network, small firms in America and national oil companies in China. Some suggestions are proposed for China: set positive policies and tax preferences, develop advanced and adaptive technologies, consummate natural gas market system and infrastructure, cooperate with foreign companies and monitor the effect of unconventional gas exploitation on environment. These summaries and suggestions can be instructive for other countries to develop unconventional gas.
Assessment of SAGD Well Configuration Optimization in Lloydminster Heavy Oil Reserve
Authors: Tavallali M.. , Maini B.. , Harding T.. , Busahmin B..
Published: March 2012

Large quantity of heavy oil resources are present in variety of complex thin reservoirs in Lloydminster area which are situated in east-central Alberta and west-central Saskatchewan. Primary depletion and waterflooding are the principal recovery techniques. Although these techniques work, the recovery factors remain low and large volumes of oil are left unrecovered when these methods have been exhausted. Because of the large quantities of sand production, many of these reservoirs end up with a network of wormholes that makes most of the displacement type enhanced oil recovery techniques inapplicable. Because of these high conductivity channels, only gravity drainage based techniques have a good chance of success.

Among the applicable methods in Lloydminster area, SAGD has not received adequate attention, mostly due to the notion that heat loss in thin reservoirs would make the process uneconomical. While this may be true, the limiting reservoir thickness for SAGD under varying conditions has not been established. These reservoirs contain light oil with sufficient mobility. Therefore the communication between the SAGD well pairs is no longer a hurdle. This opens up the possibility of increasing the distance between the two wells and introducing elements of steamflooding into the process in order to compensate for the small thickness of the reservoir.

The main objective of this study was to evaluate the effect of well configuration on SAGD performance and develop a methodology for enhancement of the SAGD performance through optimizing the well configurations for Lloydminster type of reservoir.

A new well configuration was able to significantly improve the application of SAGD in thin reservoirs of Lloydminster. It provided high RF at reasonable cSOR. The effects of some common Lloydminster reservoir characteristics, which are problematic for the SAGD process (such as initial gas saturation, bottom water, and gas-cap) were investigated for the most promising well configuration.
Closed Loop Circulating Systems Enhance Well Control and Efficiency With Precise Wellbore Monitoring and Management Capabilities
Authors: Grayson B. , Gans A. H.
Published: March 2012

The greatest risk to operational safety during the drilling and completion of a well is a kick. A gas influx, with its potential for escalation into well control event, places the crew, the environment and the rig in imminent danger.

The second greatest risk is misdiagnosis of an event and the failure to quickly and correctly take action.

For kicks and other pressure related events, the question is often fundamental—"are we experiencing losses or is the well ballooning during a connection"? The answer can be critical. An incorrect decision based on a misdiagnosed situation can result in millions of dollars in non-productive time (NPT). In the extreme, incorrect diagnosis can lead to death and injury, environmental damage and the loss of the rig.

These risks to well control and drilling efficiency are being mitigated using a handful of common oilfield technologies that are the key elements of closed-loop circulating system—rotating control devices (RCDs), flow-metering technologies, automated drilling choke systems and downhole isolation valves.

This is truly an instance of the whole being greater than the sum of the parts. That value is being further enhanced through the integration of innovative analysis and management software. These closed loop systems have proven very successful in mitigating risk and improving economics across a wide range of land and marine drilling applications and are allowing the industry to safely tackle it’s most risk-laden and costly wells.

The elements are field proven—some with more than a 40-year history—readily available from numerous vendors and are relatively economical. Individually they add incremental safety and efficiency benefits. However, when these elements are paired or used in combination with each other to create a closed and pressurizable mud-returns system, the benefits escalate at an exponential rate.

This paper examines the basics elements of a closed-loop circulating system and how this technology is enhancing the safety and efficiency of drilling and completion operations without sacrificing other operational elements.
Use of the Continuous Circulation System on the Kvitebjørn Field
Authors: Ross N. , Scaife T. , Macmillan R. , Berg P. C. , Jenner J. W.
Published: March 2012

The reasons behind Statoil choosing to include continuous circulation in HPHT Managed Pressure Drilling operations in the Kvitebjørn Field in the North Sea are explained. The paper will also discuss the preparations for the operation and the equipment and manpower required to enable the Continuous Circulation System to be installed and operated on the platform. Results recorded by the drilling team during the drilling period are described. Reference is also made to other applications of the Continuous Circulation System.
Drilling Hazard Mitigation Technology Enables Conventionally Undrillable Prospects To be Drilled With Reduced Nonproductive Time and Increased Operational Safety: Application of Solid Expandable Liners and Managed Pressure Drilling in Algeria Nezla Field
Authors: Hamoudi I. , Kartobi K. , Vieira P. , Saad M. A. , Torres F. , Qutob H.
Published: March 2012

The Nezla Field is a faulted anticline that makes conventional drilling challenging due to the presence of fractured and high pressure formations in the Triassic and Ordovician groups, representing trouble zones that jeopardize well objectives, adding costs and operational risks to the drilling process. This adverse condition was observed in the offset wells drilled with problems related to wellbore instability, lost-circulation zones and over-pressured formations leading to kick/loss well control scenarios that endangered the drilling operations and incurred significant Non-Productive Time (NPT). A Drilling Hazard Mitigation (DHM) approach was implemented to offset the risks of both deviating from the well objective and drilling plan.

The constraint to drill the planned 12-1/4?? section in the well was the unpredictability of the pore/fracture pressure in the transition zone between Tags and Sandy Tags formations, representing a high level operational risk. The most optimum and reliable solution to achieve the goal of drilling this zone without loss of hole size was to set 9-5/8?? casing shallower than planned and then isolate the lower section of Tags formation (abnormally pressurized) with an Open Hole Expandable Liner. Drilling the next hole section through the low pressure formations to set the 7?? casing shoe was to be resumed as per the original plan. This allowed the 6?? reservoir hole section to be drilled under the Managed Pressure Drilling (MPD) mode.

The CBHP (MPD technique) was planned to drill the 6?? section through the tectonically fractured Sandstone Hamra Quartzite maintaining the ECD within the drilling window limits initially defined by the predicted formation pressure and the average mud hydrostatic with which fluid losses were experienced in the offset wells. While drilling, these limits were ascertained within the range of 1.26 SG EMW - gas influx and 1.32 SG EMW - fluid losses. The CBHP drilling mode enabled to manage the ECD in between influxes and losses only adjusting the well head pressure to obtain instantaneous changes in the Bottom Hole Pressure while circulation was in progress. During the pumps-off periods, back pressure was applied on the MPD choke by pumping mud across the top of the well to compensate the Annular Friction Loss pressure. Once these limits were reached, drilling progressed with managing simultaneously small gas influxes and tolerable losses; then TD was called since the risk of simultaneous total losses and gas Influxes in the underlying Hamra fault was increasing.

This paper describes in detail the DHM technology implemented in this well and presents the successful application of such technique to enhance Nezla field exploitation. Lessons learnt and challenges encountered will be also discussed.
The Application of Advanced Gas Extraction and Analysis System Complements Early Kick Detection and Control Capabilities of Managed Pressure Drilling System With Added HSE Value
Authors: Patel B. , Cooper T. D. , Hughes S. N. , Billings W. C.
Published: March 2012

Managed Pressure Drilling (MPD) has gained industry-wide acceptance as a technology that enables drilling into the challenging zones. Narrow pore pressure – fracture pressure window, depleted reservoir zones, highly fractured reservoirs and deep-water wells are few examples of such challenges. Weatherford’s MPD system has proved its effective application in drilling challenging wells. Its unique early kick and loss detection capability helps to identify such event in very early stage, take corrective action and hence to minimize the nonproductive time. Early detection of a kick / loss event helps in minimizing the potential risk posed by the event and ensure safety during the operations.

Weatherford’s advanced gas extraction and analysis system uses an innovative membrane technology and high speed gas chromatograph to improve surface gas detection and analysis in real time. This capability was utilized in conjunction with accurate flow metering capability of MPD system. Various tests were carried out to validate the advanced gas detection system’s capability to detect and analyses gas in mud. During circulation of the influx, data from gas detection system helped to plan the strategy gas on the surface. The test data was validated by the data from real wells.

Feedback from the advanced gas detection system also helped to control the break out of the dissolved gas from oil based mud by varying surface back pressure through automated chokes. This is very critical to ensure that gases containing hydrocarbons are handled safely on the surface. It also provided quantitative analysis of the lighter and hence volatile hydrocarbon components. Circulation rates and surface back pressure can be used to mitigate potential hazards. Use of advanced gas extraction system in combination with MPD system added significant HSE value by making well control operations more efficient and safer.
Computational Modeling of Cellular Effects Post-Irradiation with Low- and High-Let Particles and Different Absorbed Doses
Authors: Tavares Adriana Alexandre S. , Tavares João Manuel R. S.
Published: March 2012

The use of computational methods to improve the understanding of biological responses to various types of radiation is an approach where multiple parameters can be modelled and a variety of data is generated. This study compares cellular effects modelled for low absorbed doses against high absorbed doses. The authors hypothesized that low and high absorbed doses would contribute to cell killing via different mechanisms, potentially impacting on targeted tumour radiotherapy outcomes. Cellular kinetics following irradiation with selective low- and high-linear energy transfer (LET) particles were investigated using the Virtual Cell (VC) radiobiology algorithm. Two different cell types were assessed using the VC radiobiology algorithm: human fibroblasts and human crypt cells. The results showed that at lower doses (0.01 to 0.2 Gy), all radiation sources used were equally able to induce cell death (p>0.05, ANOVA). On the other hand, at higher doses (1.0 to 8.0 Gy), the radiation response was LET and dose dependent (p<0.05, ANOVA). The data obtained suggests that the computational methods used might provide some insight into the cellular effects following irradiation. The results also suggest that it may be necessary to re-evaluate cellular radiation-induced effects, particularly at low doses that could affect therapeutic effectiveness.
Insulin Resistance, Cystatin C, and Mortality Among Older Adults
Authors: de Boer Ian H. , Katz Ronit , Chonchol Michel B. , Fried Linda F. , Ix Joachim H. , Kestenbaum Bryan , Mukamal Kenneth J. , Peralta Carmen A. , Siscovick David S.
Published: March 2012

OBJECTIVE

Insulin resistance is a risk factor for cardiovascular and noncardiovascular diseases. Impaired kidney function is linked with insulin resistance and may affect relationships of insulin resistance with health outcomes.

RESEARCH DESIGN AND METHODS

We performed a cohort study of 3,138 Cardiovascular Health Study participants (age ≥65 years) without diabetes. Insulin sensitivity index (ISI) was calculated from fasting and 2-h postload insulin and glucose concentrations. Associations of ISI and fasting insulin concentration with all-cause mortality were tested using Cox proportional hazards models, adjusting for demographic variables, prevalent cardiovascular disease, lifestyle variables, waist circumference, and LDL cholesterol. Subsequent models were additionally adjusted for or stratified by glomerular filtration rate estimated using serum cystatin C (eGFR).

RESULTS

A total of 1,810 participants died during the 14.7-year median follow-up. Compared with the highest quartile of ISI, the lowest quartile (most insulin resistant) was associated with 21% (95% CI 6–41) and 11% (−3 to 29) higher risks of death without and with adjustment for eGFR, respectively. Compared with the lowest quartile of fasting insulin concentration, the highest quartile was associated with 22% (4–43) and 4% (−12 to 22) higher risks of death without and with adjustment for eGFR, respectively. Similar attenuation by eGFR was observed when blood pressure, triglycerides, HDL cholesterol, and C-reactive protein were included in models.

CONCLUSIONS

Insulin resistance measured as ISI or fasting insulin concentration is associated with increased risk of death among older adults, adjusting for conventional confounding characteristics. Impaired kidney function may mediate or confound this relationship.
The “revival” of civil society in Central Eastern Europe: New environmental and political movements
Authors: Torsello Davide
Published: March 2012

The idea of civil society is one of the oldest and most contested in Western political and sociological thought. Among the social sciences, anthropology has been the discipline that has prompted the boldest critiques of the concept. This paper argues that the “revival” of civil society in Central and Eastern Europe in one particular field—that of environmental activism—has been contingent with the outcomes of EU enlargement policies. I introduce the case study of one of the most complex and contested transport development projects in Central Eastern Europe: the Budapest Ring Road. I maintain that within the EU enlargement project alternative forms of political power have been built from below and that they eventually come to compete with the state (and local governments) to influence decision-making processes. These forms, to be individuated in the emergence of environmental activism, take shape at local, state and transnational levels and aim, although often contradictorily, at restituting political agency under the condition of lowering public participation in decision-making processes.
A Conceptual Framework for Formalization of National Innovation Systems
Authors: Nasierowski Wojciech
Published: March 2012

A Conceptual Framework for Formalization of National Innovation Systems

The concept of National Innovation System (NIS) is explored from the perspective of its propensity for formalization. It is observed that there are problems with formalization (measurement) of NIS and consequently, deficiency in assessment of efficiency of pro-innovative ventures. Based on an overview of the literature, subsystems of NIS are identified and the leading topics within these subsystems are presented. Results of this study are believed to create the platform for formalization of NIS.
Growth characteristic of Welsh onion (Allium fistulosum L.) grown from seeds and transplants
Authors: Tendaj Maria , Mysiak Barbara
Published: March 2012

The characteristic growth features of four Welsh onion cultivars (‘Parade’, ‘Performer’, ‘Siedmiolatka Zielona’, and ‘Siedmiolatka Czerwona’) dependant on growing method (seeds sown directly in the field and from transplants) were evaluated during the three-year study (2007-2009). The following traits were determined: plant height, number of leaves on a single plant, tendency to produce laterals, plant weight, as well as length and diameter of the pseudostem. Plants of the ‘Parade’ cultivar were the highest (76.0 cm, on average), while those of ‘Siedmiolatka Czerwona’ were the shortest (mean 68.6 cm). Pseudostem length was found to be the main factor determining the height of the Welsh onion. The longest pseudostems were observed for the ‘Parade’ and ‘Performer’ cultivars, while the ‘Siedmiolatka Czerwona’ had the shortest.

In each of the tested cultivars, those grown from a transplant resulted in larger pseudostems and a larger number of leaves. Amongst the studied cultivars, ‘Siedmiolatka Czerwona’ had the most numerous leaves and laterals (45.2 leaves and 14.3 laterals, on average), while ‘Performer’ and ‘Parade’ had the least (mean 11.7 and 14.8 leaves and 2.4 and 2.6 laterals, respectively). The weight of a single plant with laterals significantly differed depending on the cultivar and growing method. At the end of the vegetation period (mid-October), the ‘Parade’ and ‘Performer’ cultivars grown from transplants were characterised by the highest weights (mean 518.2 g and 631.7 g), while ‘Siedmiolatka Czerwona’ and ‘Siedmiolatka Zielona’ grown from seeds had the lowest (222 g, on average).
Effect of differentiated nitrogen fertilisation on the yield and quality of leaf lettuce
Authors: Chohura Piotr , Kołota Eugeniusz
Published: March 2012

Two field experiments with leaf lettuce were conducted in 2006-2008. The first factor tested was the diversified contents of mineral nitrogen in the soil, amounting to 50, 100 and 150 mg N dm-3 before lettuce cultivation. The second factor tested four nitrogen fertilisers differing in chemical composition and in nitrogen form introduced into the soil: ammonium nitrate 34% N - (NH4NO3), calcium nitrate 15.5% N - (Ca(NO3)2 × H2O + NH4NO3), ammonium sulfate 20.0% N - ((NH4)2SO4), and ENTEC 26% N - (NH4NO3 + (NH4)2SO4 + 0.8% DNPP). Two cultivars of leaf lettuce were used: green leaf ‘Casabella’ (Lollo Bionda type) and red leaf ‘Klausia’ (Lollo Rosa type). The best source of nitrogen for ‘Casabella’ cultivar lettuce was ENTEC 26 fertiliser and calcium nitrate, which resulted in significantly higher yields as compared to ammonium sulfate, yet did not differ from the yields comprising plants fertilised with ammonium nitrate. In the case of the ‘Klausia’ cultivar, ENTEC 26 fertiliser and ammonium nitrate generated the best production results. Regardless the type of nitrogen fertiliser used, the increase in concentration of this element in soil from 50 mg N dm-3 to 150 mg N dm-3 resulted in a considerable increase in marketable yield of both cultivars with simultaneously higher nitrate accumulation and decreased dry matter in the ‘Klausia’ cultivar. Lettuce fertilised with ammonium sulfate as well as with ENTEC 26 presented significantly lower average nitrate content in leaves before harvesting than after application of ammonium and calcium nitrate as a source of nitrogen for the plants. Introduction of ammonium nitrate and calcium nitrate in the dose of 150 mg N dm-3 contributed to nitrate accumulation in the amounts exceeding permissible by legal regulations regarding the content of this element in lettuce, while application of ENTEC 26 allowed us to obtain a high yield size of both lettuce cultivars without risk of exceeding permissible nitrate content.
Growth retardants in the cultivation of Chrysanthemum × grandiflorum (Ramat.) Kitam. ‘Leticia Time Yellow’
Authors: Zakrzewski Piotr , Schroeter-Zakrzewska Anita
Published: March 2012

The objective of the presented experiment was the showing of the possibility of replacing daminozide, contained in the preparation B-Nine 85 SP, by metconazole, contained in Caramba 60 SL preparation, in pot cultivation of pot chrysanthemum ‘Leticia Time Yellow’. Experiment was carried out in three cycles: in the spring, beginning 10 April; in the summer, beginning 11 June; and in the autumn, beginning 13 August, 2007. The metconazole contained in the Caramba 60 SL preparation was able to impede the growth of ‘Leticia Time Yellow’ chrysanthemum as effectively as the daminozide contained in the B-Nine 85 SP preparation. However, the effectiveness of metconazole depended on its concentration and on the dose of the preparation, on the number of treatments and on the growing term in the plastic tunnel. In the summer term of cultivation, the effect of metconazole applied only once in a concentration of 300 mg dm-3 was comparable with the effectiveness of daminozide applied twice in a concentration of 2,550 mg dm-3, and in the autumn cultivation, the effectiveness was even higher. In addition, no retardation of flowering was recorded, either in relation to the plants sprayed with daminozide or in relation to the control plants not sprayed with any retardant.
Effect of synthetic mulches on melon (Cucumis melo L.) yielding
Authors: Kosterna Edyta , Zaniewicz-Bajkowska Anna , Franczuk Jolanta , Rosa Robert , Chromińska Krystyna , Borysiak-Marciniak Izolda , Panasz Marzena
Published: March 2012

A field experiment was carried out in 2006-2008. The study examined the effect of soil mulching with synthetic materials (black polyethylene film, black polypropylene nonwoven 50 g m-2, and black polypropylene fabric 94 g m-2) on the fruit yield and quality of two melon cultivars (‘Seledyn’ and ‘Yupi’) grown in the field under the climatic conditions of central-eastern Poland. Specimens grown without mulching served as the control. The climatic conditions during the study years had a significant influence on the level of total, marketable and early yield of melon. The highest melon yield was obtained in 2007, which was characterised by the most favourable weather conditions for melon cultivation. The comparison of the cultivars showed that ‘Seledyn’ was better adapted to the climatic conditions of Poland. From cultivation, this cultivar achieved significantly higher early and total fruit yield compared with ‘Yupi’. ‘Seledyn’ was also characterised by a higher share of early yield of the total yield, a higher number of fruit in the early yield and a higher mean fruit weight. In turn, ‘Yupi’ produced a significantly higher share of marketable yield of the total yield and a higher number of marketable fruit.
Comparison of far field characterisation of DOEs with a goniometric DUV-scatterometer and a CCD-based system
Authors: Wurm Matthias , Bonifer Stefanie , Bodermann Bernd , Gerhard Michael
Published: March 2012

We have measured far field diffraction patterns of different diffractive optical elements at an illumination wavelength of 193 nm using a new type of goniometric DUV (deep ultraviolet) scatterometer. This system offers both a high dynamic range and angular resolution. The scatterometer is especially suitable to analyse weak background light like stray light and local variations of the diffraction patterns over the DOEs (diffractive optical element). The measurement results are compared with measurements using a CCD (charge-coupled device)-based imaging DOE measurement system. An excellent agreement of the measured far field distributions is demonstrated.
HVPE growth and characterization of GaP on different substrates and patterned templates for frequency conversion devices
Authors: Tassev V. , Bliss D. , Snure M. , Bryant G. , Peterson R. , Bedford R. , Yapp C. , Goodhue W. , Termkoa K.
Published: March 2012

This article describes efforts to achieve fast deposition of thick Quasi-Phase-Matched (QPM) GaP structures with high surface and structural quality on oriented patterned (OP) templates in a Hydride Vapor Phase Epitaxial (HVPE) process. These QPM structures will be incorporated in devices for conversion of frequencies from the near infrared to the mid infrared and THz regions, where powerful and tunable sources are in great demand for both military and civilian applications. In contrast with GaAs - the most studied OP QPM material - the two-photon absorption of GaP is predicted to be extremely low, which allows pumping with a number of convenient sources between 1 – 1.7 μm. Unpatterned GaP layers up to 370 μm thick were grown with growth rates up to 93 μm/hr with high reproducibility on bare substrates. The layers demonstrated smooth surface morphology with RMS < 1 nm and high structural quality with FWHM equal to 39 arcsec for layers grown on GaP and 112 arcsec for those grown on GaAs. Growth on OP-GaP templates resulted in 142 μm thick QPM structures deposited at a growth rate of 71 μm/h with good vertical (normal to the layer surface) propagation of the initial pattern. When the growth was performed on OP-GaAs one of the domains showed a trend toward a faceting growth. Further investigations are in progress to equalize the vertical and lateral growth of the two domains, and determine the best orientation of the substrate and pattern in order to achieve structures thick enough for high power nonlinear applications.
Developments in Undergraduate Teaching of Small-Animal Soft-Tissue Surgical Skills at the University of Sydney
Authors: Gopinath Deepa , McGreevy Paul D. , Zuber Richard M. , Klupiec Corinna , Baguley John , Barrs Vanessa R.
Published: March 2012

This article discusses recent developments in soft-tissue surgery teaching at the University of Sydney, Faculty of Veterinary Science. An integrated teaching program was developed for Bachelor of Veterinary Science (BVSc) students with the aim of providing them with optimal learning opportunities to meet “Day One” small-animal soft-tissue surgical competencies. Didactic lectures and tutorials were introduced earlier into the curriculum to prepare students for live-animal surgery practica. In addition to existing clinics, additional spay/neuter clinics were established in collaboration with animal welfare organizations to increase student exposure to live-animal surgery. A silicon-based, life-like canine ovariohysterectomy model was developed with the assistance of a model-making and special effects company. The model features elastic ovarian pedicles and suspensory ligaments, which can be stretched and broken like those of an actual dog. To monitor the volume and type of student surgical experience, an E-portfolio resource was established. This resource allows for the tracking of numbers of live, student-performed desexing surgeries and incorporates competency-based assessments and reflective tasks to be completed by students. Student feedback on the integrated surgical soft-tissue teaching program was assessed. Respondents were assessed in the fourth year of the degree and will have further opportunities to develop Day One small-animal soft-tissue surgical competencies in the fifth year. Ninety-four percent of respondents agreed or strongly agreed that they were motivated to participate in all aspects of the program, while 78% agreed or strongly agreed that they received an adequate opportunity to develop their skills and confidence in ovariohysterectomy or castration procedures through the fourth-year curriculum.
Characteristics of Heavily Edited Objects in OpenStreetMap
Authors: Mooney Peter , Corcoran Padraig
Published: March 2012

This paper describes the results of an analysis of the OpenStreetMap (OSM) database for the United Kingdom (UK) and Ireland (correct to April 2011). 15, 640 OSM ways (polygons and polylines), resulting in 316, 949 unique versions of these objects, were extracted and analysed from the OSM database for the UK and Ireland. In our analysis we only considered “heavily edited” objects in OSM: objects which have been edited 15 or more times. Our results show that there is no strong relationship between increasing numbers of contributors to a given object and the number of tags (metadata) assigned to it. 87% of contributions/edits to these objects are performed by 11% of the total 4128 contributors. In 79% of edits additional spatial data (nodes) are added to objects. The results in this paper do not attempt to evaluate the OSM data as good/poor quality but rather informs potential consumers of OSM data that the data itself is changing over time. In developing a better understanding of the characteristics of “heavily edited” objects there may be opportunities to use historical analysis in working towards quality indicators for OSM in the future.
Apocalypse XXI-XXII et l'iconographie du portail central de la nef de Vézelay
Authors: Angheben Marcel
Published: March 2012

It is now generally accepted that Pentecost is in fact the theme of the tympanum of the central portal of the nave of the church at Vézelay - Pentecost, an event which was then regarded, as it still is, as the founding act of the Church. Representations of Apostles are seen at various points on the portal, indicating that the Church is already at work, teaching and preaching. In order to evoke the nature of the Church, the creator of the concept for the portal appears to have drawn on the two final chapters of the Apocalypse (21 and 22) and the relevant exegesis. For a characteristic feature of these texts is that pratically ail the component elements of the portal are therein alluded to, either directly or more or less implicitly. And it is from this source that certain of those elements derive their meaning, namely the waters at the feet of Christ ; the throne on which he sits ; the figures carved on the embrasure and the representation of John the Baptist ; and especially the zodiac with its four insets as well as the two capitals on the right-hand side. It is perfectly possible therefore that the conception of the iconographie message of the portai should have taken shape with those chapters of the Apocalypse in mind.
Aliénor d'Aquitaine conduite en captivité. Les peintures murales commémoratives de Sainte-Radegonde de Chinon
Authors: Kenaan-Kedar Nurith
Published: March 2012

La vie et l'œuvre d'Aliénor d'Aquitaine ont été fréquemment décrites et étudiées par les érudits, anciens et contemporains. Toutefois, les historiens, dans leur majorité, ont concentré leur attention sur les deux mariages d'Aliénor, avec Louis VII et Henri II Plantagenêt, négligeant l'étude de son rôle culturel et politique à l'apogée de sa vie. Suivant la voie tracée par Edmond-René Labande et sa magistrale étude, nous analysons, dans le présent article, les peintures murales de Sainte-Radegonde de Chinon et le cycle sculpté de la salle capitulaire de Sainte-Radegonde de Poitiers — deux œuvres qui, selon nous, sont le reflet des chapitres majeurs de la vie d'Aliénor et font la lumière sur son attitude et ses projets à la fin de sa vie.
L'empereur, l'imposteur et la rumeur : Henri V ou l'échec d'une « réhabilitation »
Authors: Lecuppre Gilles
Published: March 2012

Still nowadays, the German emperor Henry V remains the victim of some ill-treatment among historians, owing to the castigation he once had to endure from his enemies of the Gregorian party. However, a peculiar event nearly brought him salvation during the XIIth and the XIIIth centuries. An impostor impersonated the late monarch around 1138, meeting no real success, and being finally secluded in the monastery of Cluny. From the episode nevertheless originated a strong and persistent rumour about a pious survival of Henry V, which was at first used as an exemplum connected to a similar legend concerning the Anglo-Saxon Harold, but was eventually rejected by chroniclers as a mere fiction.
Culture et art figuratif à Pise au XIIe siècle : Les fonts baptismaux de Calci
Authors: Ducci Annamaria
Published: March 2012

Nella chiesa battesimale di Calci (Pisa) si conserva un monumentale fonte battesimale del XII secolo, ricavato in un unico blocco lapideo : di struttura quadrangolare, esso è scolpito sul fronte con la raffigurazione del Battesimo di Cristo. L'opera si presenta corne uno dei casi più complessi nel panorama della scultura del XII secolo in Toscana, sia per la tipologia che per le soluzioni iconografiche, in quanto vi confluiscono variate componenti culturali. In primo luogo la tradizione delle nozioni relative alla simbologia del battesimo ; l'invenzione del tutto originale degli animali impiegati corne sostegno, che instaura rapporti con il mondo figurativo transalpino ; infine, l'aperta deferenza verso la tradizione classica, conosciuta attraverso i molti sarcofagi della città, e che non è solo formale, ma bensi rivela la supravvivenza di un sostrato concettuale mai cancellato, anzi riadattato in chiave cristiana. Il maestro del fonte di Calci si mostra ben al corrente delle nozioni enciclopediche e perfettamente inserito nel clima di rinascita che caratterizza la romanitas pisana del secolo. Nel fonte battesimale è dunque legittimo individuare a pieno titolo una delle testimonianze più vive di questa cultura (non solo figurativa), rivolta al Nordeuropa, al Mediterraneo e al mondo passato dei classici, e che a Pisa nel XII secolo dovette essere particolarmente viva e feconda.
Tabous, fantasmes et pensée magique autour de la naissance
Authors: Squires Claire
Published: March 2012

Résumé La connaissance des croyances et coutumes d’autres traditions concernant la mort, la naissance, le masculin et le féminin est éclairée par la considération des pulsions, de l’œdipe, de l’interdit de l’inceste ou des différences de générations. Nous examinerons la pensée magique dans certains travaux anthropologiques et psychanalytiques sur la maternité et la naissance d’un enfant. Ensuite, nous nous demanderons si la transmission des traumatismes, des phénomènes de répétition, des deuils non élaborés à des enfants est éclairée par l’interprétation psychanalytique des mécanismes de pensée magique. Enfin, nous montrerons comment la coïncidence de la mort et de la naissance chez une mère ayant connu une mort in utero peut la conduire à se trouver, lors de la naissance d’un enfant suivant, dans un état d’angoisse et de contagiosité psychique conduisant à des mécanismes de pensée archaïque chez son enfant.
Les avatars de la pensée magique
Authors: Ceccarelli Paulo , Lindenmeyer Cristina
Published: March 2012

Résumé Les auteurs développent l’idée que la pensée magique trouvera aussi sa forme d’expression dans d’autres cultures. À partir des exemples rencontrés par des anthropologues, les auteurs abordent ce « reliquat de la mentalité primitive » qui subsiste toujours sous une forme latente dans le psychisme de tout un chacun. Les auteurs développent leurs réflexions appuyées sur l’idée que la pensée magique constituerait une tentative d’échapper aux angoisses et aux conflits et du monde externe et du monde interne ; comme si l’acte de penser pouvait contrôler, expliquer et même changer la réalité.
Pensée magique et inconscient réel : jouissance et politique dans la psychanalyse chez Lacan et chez Deleuze/Guattari
Authors: Gabarron-Garcia Florent
Published: March 2012

Résumé Le problème de la « pensée magique », problème typique de l’anthropologie, a été, classiquement, arraisonné à la « pensée sauvage ». Dans le même temps la fonction symbolique ramenée à une fonction de classement, l’inconscient était dès lors forclos. Or, sous l’horizon d’un poststructuralisme assumé, on peut repérer deux réponses psychanalytiques majeures s’articulant autour de la catégorie de Réel : celle de Lacan et de Deleuze/Guattari qui reprennent à nouveaux frais la théorie de la psychose à partir d’une réflexion sur l’artiste et sa production (Artaud et Joyce). En effet avec la lalangue, la jouissance et l’enjeu schizo-analytique, non seulement la communauté problématique des causes du chaman et celles du psychanalyste deviennent à nouveau justiciables d’investigations, mais se dessine également un nouveau rapport du psychanalyste au capitalisme quant à la question de sa praxis. Le bon mot de Lacan de 69, inspiré par Foucault, le préfigurait d’ailleurs : désormais ce sont « les structures qui descendent dans la rue ». Restait à le penser et à se donner les outils conceptuels non structuraux d’un tel événement.
Le temps perdu est-il retrouvé ? Proust et la pensée magique
Authors: Bernateau Isée
Published: March 2012

Résumé À la recherche du temps perdu de Proust se présente comme une œuvre entièrement placée sous l’égide de la pensée magique, laquelle, par le miracle d’une analogie, fait coïncider passé et présent et abolit toutes les différences. Mais cette exigence narcissique est d’autant plus impérieuse qu’elle se fonde sur la certitude d’une perte de la toute-puissance due à l’action du temps. Le temps, vecteur de séparation et de mort, est à la fois ce qui origine et ce qui empêche le mouvement de l’œuvre.
Freud et Mauss, Lacan et Lévi-Strauss : rencontres et malentendus
Authors: Richard François
Published: March 2012

Résumé N’allant pas de soi et pourtant incontournable, la fonction paternelle est l’axe central de cet article. L’auteur traverse un siècle de débat autour du système de parenté, devenu dans le vocabulaire de notre modernité : les nouvelles formes de parentalité, où la fonction paternelle comme principe de tiercéité et d’échange intersujets apparaît comme défaillante à faire face à un mélange d’organisation et de désorganisation. Ainsi, d’un œdipe organisateur symbolique, on glisse vers un œdipe, comme une symbolique sans conflit, sollicitant ainsi un débat autour de la sexualité, l’inceste, la dimension symbolique et le statut de l’inconscient. Seront confrontées des approches aussi bien psychanalytiques qu’anthropologiques (Freud, Mauss, Lévi-Strauss, Lacan, Green, Mannoni, Godelier, Juillerat…). À côté de l’inconscient freudien, il y a l’inconscient spécifique de la relation aux morts des rituels funéraires et des mythes dans les sociétés étudiées par les ethnologues. Les approches contemporaines des pathologies transgénérationnelles retrouvent à leur manière cet inconscient des anthropologues.
L'effacement des affects comme restauration d'une enveloppe psychique et corporelle : œuvre de Thanatos ou d'Éros ?
Authors: Guittonneau Mireille
Published: March 2012

Résumé La clinique des adultes n’est pas seule à témoigner d’un tableau marqué par une absence d’affects. Le travail avec les enfants fait également apparaître cette manifestation défensive et conduit à l’interroger autrement. Ainsi, l’effacement des affects auquel recourent précocement certains sujets est-il toujours l’œuvre des pulsions de mort ? En effet, lorsque les affects en viennent à se confondre avec une menace d’effraction ou de déformation de soi, leur effacement semble parfois s’imposer comme façon de reconstituer une fragile enveloppe psychique et corporelle et de préserver l’ébauche d’un objet interne. L’effacement des affects se révélerait être alors le résultat d’une tentative paradoxale de survie, dirigée par Éros.
Un père à la lettre
Authors: Jejcic Marie
Published: March 2012

Résumé La question de la lettre se présente dans la clinique comme étant hermétique donc plutôt lacanienne. Il est intéressant de suivre son statut chez Freud pour comprendre le rôle déterminant qu’elle joue aujourd’hui et sans doute pour l’avenir de la psychanalyse. Nous proposons de mettre en perspective trois célèbres écrits de Freud. Échelonnés sur des périodes différentes, ils confirment la justesse et la nécessité du retour à Freud par Lacan toujours nécessaire pour articuler les questions de façon fondamentale. Freud rend compte sans pouvoir le justifier de la grande violence du scénario qui se produisait chaque fois qu’il était confronté accidentellement à la question de l’origine, donc des dieux et du père. Dans les trois textes, surgit une lettre qui fait trébucher Freud et provoque un effet inattendu de dépersonnalisation. Cela nous permet de considérer les fondements de cet étrange rapport du père à la lettre. Notre analyse démontre qu’un père se lit à la lettre. Ce temps de dépersonnalisation qui ne fut pas analysé chez Freud regarde toujours la psychanalyse d’autant que la question du père est au centre du remaniement de société auquel aujourd’hui elle est confrontée.
Le territoire de l'autre : notre devoir d'hospitalité
Authors: Lesenne Philippe
Published: March 2012

Résumé Nous assistons, depuis de nombreuses années, à un changement du paysage social qui interroge nos pratiques professionnelles et, plus radicalement, le fondement institutionnel de nos établissements sociaux. Les politiques sociales, et notamment celle de 2002-2, pas seulement autour du droit des usagers, mais sur la police des établissements, les évaluations internes et externes, les incitations aux mutualisations de moyens, les regroupements…, sont inscrites dans une période traversée par une crise de l’institution en général, par des contraintes économiques, une évolution des populations accueillies, de l’articulation complexe du collectif et de l’individu, et la perte de la fonction d’autorité?: autant d’éléments qui nous convoquent à re-penser le territoire d’hospitalité que nous sommes en devoir d’offrir aux jeunes et à leurs familles. La proposition de ce texte s’attache délibérément à questionner, plutôt que de poser la question de l’autre, à formuler la problématique, ou plutôt la dialectique qui est à l’œuvre dans notre rencontre à l’autre, obligée pour lui et qui nous oblige.
Les enfants vulnérables
Authors: Puyuelo Rémy
Published: March 2012

Résumé Les enfants des mecs doivent être pensés non seulement en termes de causalité événementielle, mais aussi de façon éthique. Ils nécessitent une approche psychopathologique élargie faisant appel à la pensée complexe (E. Morin). Cela permet d’appréhender et de clarifier les processus éducatifs à l’œuvre dans les démarches institutionnelles, tout en questionnant notre militantisme pour l’enfance.