bluuebunny/crossref_metadata_2025_split huggingface dataset:
Estimating Zonal Flow Contributions in Deep Water Assets From Pressure and Temperature Data
Authors: Hasan A. Rashid , Sohel Rayhana N. , Wang Xiaowei 
Published: October 2017

Producing hydrocarbon from deep water assets is extremely challenging and expensive. A good estimate of rates from multiple pay zones is essential for well monitoring, surveillance, and workover decisions. Such information can be gleaned from flowing fluid pressure and temperature; deep-water wells are often well instrumented that offers such data on a continuous basis. In this study a model is presented that estimates zonal flow contributions based on energy and momentum balances. Kinetic and heat energy coming from the reservoir fluid to the production tubing is accounted for in the model. The momentum balance for wellbore takes into account differing flow profile in laminar and turbulent flows.
In addition, when sandface temperature data are not available, a recently developed analytical model to estimate the effect of Joule-Thompson expansion on sandface temperature was used to estimate sandface temperature from reservoir temperature. The model developed can be applied to any reservoir with multiple pay zones and is especially useful for deep-water assets where production logging is practically impossible. Available field data for multiphase flow was used to validate the model. Sensitivity analyses were performed that showed accurate temperature data is essential for the model to estimate zonal contribution accurately.
Wave Drift Forces and Low Frequency Damping on the Exwave FPSO
Authors: Fonseca Nuno , Stansberg Carl Trygve 
Published: October 2017

A method is followed in the present analysis to estimate realistic surge and sway wave drift force coefficients for the Exwave FPSO. Model test data is used to identify the difference frequency wave exciting force coefficients based on a second order signal analysis technique. First, the slowly varying excitation is estimated from the relationship between the incoming wave and the low frequency motion using a linear oscillator. Then, the full QTF of the difference frequency wave exciting forces is defined from the relationship between the incoming waves and the second order force response. The process identifies also the linearized low frequency damping.
The paper presents results from a few cases selected from the Exwave JIP test matrix. Empirical mean wave drift coefficients are compared to potential flow predictions. It is shown that the latter underestimate the wave drift forces, especially at the lower frequency range where severe seastates have most of the energy. The sources for the discrepancies are discussed.
Local Design Pressures During Ship Ram Events Modeling the Occurrence and Intensity of High Pressure Zones
Authors: Ralph Freeman , Jordaan Ian 
Published: October 2017

During ship ice interaction events (i.e. rams with multi-year ice), the occurrence of local pressures vary in time and space. A link between local pressures and global forces is the sum of the local forces from n High Pressure Zones (HPZs) across the interaction face equals the total force transmitted into the structure.
In this paper, a model for HPZ density, and force during ship ram events is presented. The occurrence and intensity of HPZs on panel areas were simulated using a Poisson process and an exponential distribution for HPZ force. The model is extended to consider HPZ occurrence in time through a ramming event, modeling HPZ rate. Such a model allows the designer to determine baseline ‘parent’ local pressure design parameters based on vessel size and expected operational speed. The faster a ship operates through an ice regime, the greater the HPZ rate. Larger and faster ships will penetrate further, having longer interaction durations and hence a greater number of HPZs forming (unless, for example, the ship passes through a ridge). Rates too will vary along the vessel being greater on the bow and least from mid-body to stern. For design, we are interested in the maximum local pressure on a single panel area through the ram duration.
The results are compared with previous local pressure models for design.
Wave-Current Interaction Effects on Airgap Calculations
Authors: Hermundstad Elin Marita , Hoff Jan Roger , Fonseca Nuno , Bjørkli Rune 
Published: October 2017

The importance of wave-current interaction effects on the determination of mean drift forces on floating offshore structures is well documented. Wave-current interaction effects will also influence the first-order motions and loads as well as the diffracted and radiated waves around the structure. One of the significant contributions to the influence of wave-current interaction effects on the motion responses is the additional coupling between motion modes due to the current. These effects are well known from seakeeping calculations of ships with forward speed. A structure with fore-aft symmetry will have no hydrodynamic coupling between heave and pitch in regular waves only. Due to the presence of a current, the symmetry of the flow around the body is lost, resulting in hydrodynamic coupling between the modes. This will also occur for a moored structure with slowly varying motions in the horizontal plane. The most important couplings are from the heave motion into pitch and surge and from heave to roll and sway. These couplings are otherwise present only for asymmetric structures. Due to the presence of the heave resonance and cancellation periods, the motion responses in roll and pitch for a semi-submersible will be influenced by the wave-current interaction effects. Due to the differences in phase between the different motion modes, the hydrodynamic coupling may have significant influence on the rotational motions roll and pitch and thus significant influence on the prediction of airgap. This coupling between the heave and roll/pitch modes due to the current adds complexity to the numerical simulations since the structure responses are more sensitive to the actual orientation of the structure, mooring configuration etc.
A three-dimensional linear potential flow code, MULDIF, has been developed by SINTEF Ocean. This code accounts for hydrodynamic interaction between waves and current from arbitrary directions. The code can be applied to single or multiple bodies in infinite or finite water depth. Verification studies have previously shown good agreement with other numerical codes, Hermundstad et.al. [1], Zhiyuan et.al [2].
Validation studies with emphasis on airgap and comparison with experimental results are presented and numerical results for airgap and upwell are visualized and discussed. It is demonstrated how MULDIF can be used in airgap studies.
New Combined CFD and Model Testing Technique for Identification of Wave Impact Loads on a Semisubmersible
Authors: Pakozdi Csaba , Östman Anders , Abrahamsen Bjørn C. , Økland Ole D. , Vestbøstad Tone M. , Lian Gunnar , Stansberg Carl T. 
Published: October 2017

A procedure is presented describing how to estimate realistic loads using combined numerical and model test data. Measured platform motions are imposed on the structure during the CFD analysis. The combination of the wave matching procedure with the imposed measured platform motion gives a very good numerical reproduction of the observed extreme event. The numerical reproduction of model test events provide all necessary information on the hydrodynamic loads for further structure analysis. This represents an improvement in industry design applications.
Imposing the measured motion from regular wave model test into CFD simulation is validated by comparison of relative wave height time series. This comparison shows a very good agreement between the measured and the simulated time series. Existing model test data from irregular model test and CFD generated numerical wave are compared. A wave matching procedure has been developed, which shows very promising results with respect to reproducing critical hydrodynamic conditions observed during the model tests. This paper presents a case study how CFD can be used to enhance model test data in an efficient way to provide the critical hydrodynamic conditions for structure analysis. Comparison of the measured free surface elevation of the calibrated waves with the time series of the numerical waves, as well as the measured and simulated relative wave probes time series and the slamming load time series show that the applied numerical wave events show similar physical conditions as those observed in the model test. The effect of the platform motion on the impact force is identified by comparison of the impact force time series of the simulation with and without platform motion against model test time series. The results demonstrate that the approach provides a clear improvement compared to numerical or model testing alone. The observed steep wave events are numerically reproduced in a simplified manner, instead of trying to reproduce measured events directly. This approach significantly reduces the computational time, as well as computational costs, to an industrially acceptable level. Traditional load estimation is not able to provide such reliable detailed local load history for structural design purpose at areas exposed to wave impacts. This new procedure, where CFD simulates realistic breaking waves with coupling to measured vessel motion, offers new possibilities for the design of structures subject to risk of wave impact loading.
Technical Challenge on VLFS in Japan After Mega-Float Project
Authors: Suzuki Hideyuki , Harada Hidetoshi , Natsume Takumi , Maeda Katsuya , Iijima Kazuhiro , Hayashi Tatsuya 
Published: October 2017

Intensive research and development of Mega-float was implemented by Technological Research Association of Mega-Float (TRAM) in late 1990s. Mega-float is a concept of a pontoon type VLFS installed in protected calm water typically large bay, and the concept was promoted by TRAM after relatively long concept development phase in Japan.
This paper reviews the research and development of VLFS in Japan. The research and development of Mega-float is briefly reviewed firstly and two research and developments after Mega-float are reviewed.
Concerning development of Oil-Gas development, logistic hub concept has been developed by J-DeEP, a consortium comprised of major Japanese heavy industries, shipping company, ClassNK and NMRI, and proposed for presalt oil field development offshore Brazil.
Another research is pontoon type coal storage and offloading facility to be installed offshore South Sumatra, Indonesia. The coal storage and offloading facility was investigated by JIP comprised of JMU, ClassNK, Osaka University and University of Tokyo.
Hydroelastic Responses of VLFS Deployed Near Islands and Reefs
Authors: Wu Yousheng , Ding Jun , Li Zhiwei , Ni Xinyun , Wu Xiaofeng , Tian Chao 
Published: October 2017

The rapid expansion of world population, the exhausting of inland resources and the requirement of sustainable development of world economy have strengthened the efforts of mankind to increase the capability of resource exploitation and space utilization in the ocean. Very Large Floating Structures (VLFS) are among those marine structures that have attracted long lasting attention in ocean utilization for several decades. The applications of different size VLFS as floating piers, floating airports, floating hotels, floating fuel facilities and even floating cities have triggered extensive researches. Several projects including the conceptual design and construction of VLFS have been launched, for instance, Mega-Float in Tokyo Bay, Floating oil storage bases in Kamigoto and Shirashima islands, Floating emergency rescue bases in Yokohoma, Floating performance stage in Singapore, Large floating bridge in Norway, Mobile offshore base (MOB) in USA and Multi-purpose floating base near islands in China.
Due to much larger dimensions, relatively smaller global rigidities and lower natural frequencies than an ordinary ship, a VLFS has apparent flexible body responses rather than rigid body motions in waves. Hence hydroelastic analyses are of great importance in design and safety assessment of a VLFS. Extensive researches have been carried out during the past decades in the development of prediction methods of hydroelastic responses of VLFSs. However, most publications in this field were for VLFSs in open sea. If a VLFS is deployed near islands and reefs in complicated geographical environment, the wave conditions, wave loads and the hydroelastic responses of a VLFS will be quite different than in open sea.
In this paper the three-dimensional hydroelasticity theories that have been widely used in the analysis of a VLFS in deep or shallow open sea with constant water depth are briefly introduced. Based on these theories the numerical approaches of hydroelastic analyses of a VLFS near island and reefs in shallow sea, developed recently by CSSRC, are described. Some important technical problems, including description of wave environment, design scheme, connectors between modules, hydroelastic responses, coupled responses with mooring system and safety analysis of a VLFS deployed near islands and reefs are also discussed.
Hydrodynamical Aspects of Pontoon Optimization for a Side-Anchored Floating Bridge
Authors: Fredriksen Arnt G. , Heiervang Mads F. , Larsen Per N. , Sandnes Pål G. , Sørby Bernt , Bonnemaire Basile , Nesteby Anders , Nedrebø Øyvind 
Published: October 2017

Long floating bridges supported by pontoons with span-widths between 100m and 200m are discrete hydro-elastic structures with many critical eigenmodes. The response of the bridge girder is dominated by vertical eigenmodes and coupled horizontal modes (lateral) and rotational modes (about the longitudinal axis of the bridge girder). In this paper it is focused on design principles to reduce the response with regards to these eigenmodes.
It is shown for a floating bridge with 200m span-width that by inserting a bottom flange the vertical eigenmodes can be lifted out of wind driven wave regime. It is also shown that selecting a pontoon length that give cancellation of excitation forces is beneficial, and that the geometrical shaping of the pontoon can be efficient to decrease the bridge response.
Torsion in Flexible Pipes, Umbilicals and Cables Under Loadout to Installation Vessels
Authors: Mainçon Philippe 
Published: October 2017

Operations where a flexible pipe, umbilical or cable is loaded out from an on-shore spool to the hold of an installation vessel can cause a build-up of torsion. In unfavourable cases, the torsion has been known to cause spiralling or various forms of damage to the tensile armour.
This paper presents a vocabulary for the description of torsion. It then gives a short review of design codes, enumerates known failure modes (some of which have not always been identified as torsion related), and discusses the mechanisms of torsion generation, with an emphasis on the effect of internal friction. It concludes with some ideas on torsion prevention.
Immunohistochemical Investigations of Treatment with Ro 13-3978, Praziquantel, Oxamniquine, and Mefloquine in Schistosoma mansoni-Infected Mice
Authors: Panic Gordana , Ruf Marie-Thérèse , Keiser Jennifer 
Published: October 2017

ABSTRACTTo date, there is only one drug in use, praziquantel, to treat more than 250 million people afflicted with schistosomiasis, a debilitating parasitic disease. The aryl hydantoin Ro 13-3978 is a promising drug candidate within vivoactivity superior to that of praziquantel against both adult and juvenileSchistosoma mansoniorganisms. Given the drug's contrasting low activityin vitroand the timing of its onset of actionin vivo, it was postulated that immune-assisted parasite clearance could contribute to the drug'sin vivoactivity. We undertook histopathological studies to investigate this hypothesis. Infected mice were treated with an effective dose of Ro 13-3978 (100 mg/kg of body weight) and were dissected before and after the drug'sin vivoonset of action. The veins and livers were excised, paraffin-embedded, and sectioned, and macrophages (IBA-1), neutrophils (Neutro), B cells (CD45R), and T cells (CD3) were stained by immunohistochemistry. For comparison, samples from infected untreated mice and mice treated with effective doses of praziquantel (400 mg/kg), oxamniquine (200 mg/kg), and mefloquine (200 mg/kg) were examined. At 24 h after treatment with Ro 13-3978, significant macrophage recruitment to the veins was observed, along with a modest increase in circulating B cells, and at 48 h, neutrophils and T cells are also present. Treatment with praziquantel and oxamniquine showed similar patterns of recruitment but with comparatively higher cellular levels, whereas mefloquine treatment resulted in minimal cell recruitment until 3 days posttreatment. Our study sheds light on the immediate immune responses to antischistosomal treatment in mice and provides further insight into immune effector mechanisms of schistosome clearance.
Pharmacokinetic Interactions between Simeprevir and Ledipasvir in Treatment-Naive Hepatitis C Virus Genotype 1-Infected Patients without Cirrhosis Treated with a Simeprevir-Sofosbuvir-Ledipasvir Regimen
Authors: Bourgeois Stefan , Horsmans Yves , Nevens Frederik , van Vlierberghe Hans , Moreno Christophe , Beumont Maria , Vijgen Leen , van Eygen Veerle , Luo Donghan , Hillewaert Vera , Van Remoortere Pieter , van de Logt Jolanda , Ouwerkerk-Mahadevan Sivi 
Published: October 2017

ABSTRACT

Interactions between simeprevir (hepatitis C virus [HCV] NS3/4A protease inhibitor) and ledipasvir (HCV NS5A replication complex inhibitor) were investigated in treatment-naive HCV genotype 1-infected patients without cirrhosis, treated with simeprevir-sofosbuvir-ledipasvir in a two-panel, phase 2, open-label study. Patients had stable background treatment with sofosbuvir (400 mg once daily [QD]). In panel 1 (
n
= 20), the effect of ledipasvir (90 mg QD) on simeprevir (150 mg QD) was studied. Patients received simeprevir and sofosbuvir from days 1 to 14; steady-state pharmacokinetics (PK) of simeprevir was assessed (day 14). On day 15, ledipasvir was added and steady-state PK of simeprevir in the combination was evaluated (day 28). In panel 2 (
n
= 20), the effect of simeprevir on ledipasvir was investigated. From days 1 to 14, patients received ledipasvir and sofosbuvir and steady-state PK of ledipasvir was assessed (day 14). On day 15, simeprevir was added and a full PK profile was obtained (day 28). The least-squares mean maximum plasma concentration and area under the concentration-time curve (90% confidence interval) increased 2.3-fold (2.0- to 2.8-fold) and 3.1-fold (2.4- to 3.8-fold) for simeprevir, respectively (panel 1), and 1.6-fold (1.4- to 1.9-fold) and 1.7-fold (1.6- to 2.0-fold) for ledipasvir, respectively (panel 2), in the presence versus the absence of the other drug. All patients achieved sustained virologic responses 12 weeks after treatment end. Adverse events, mainly grade 1/2, occurred in 80% of patients; the most common was photosensitivity (45%). Due to the magnitude of interaction and the limited amount of safety data available, the use of this treatment combination is not recommended. (This study has been registered at ClinicalTrials.gov under registration no. NCT02421211.)
Role of Alanine Racemase Mutations in Mycobacterium tuberculosis
d
-Cycloserine Resistance
Authors: Nakatani Yoshio , Opel-Reading Helen K. , Merker Matthias , Machado Diana , Andres Sönke , Kumar S. Siva , Moradigaravand Danesh , Coll Francesc , Perdigão João , Portugal Isabel , Schön Thomas , Nair Dina , Devi K. R. Uma , Kohl Thomas A. , Beckert Patrick , Clark Taane G. , Maphalala Gugu , Khumalo Derrick , Diel Roland , Klaos Kadri , Aung Htin Lin , Cook Gregory M. , Parkhill Julian , Peacock Sharon J. , Swaminathan Soumya , Viveiros Miguel , Niemann Stefan , Krause Kurt L. , Köser Claudio U. 
Published: October 2017

ABSTRACT

A screening of more than 1,500 drug-resistant strains of
Mycobacterium tuberculosis
revealed evolutionary patterns characteristic of positive selection for three alanine racemase (Alr) mutations. We investigated these mutations using molecular modeling,
in vitro
MIC testing, as well as direct measurements of enzymatic activity, which demonstrated that these mutations likely confer resistance to
d
-cycloserine.
New Variant of
mcr-3
in an Extensively Drug-Resistant Escherichia coli Clinical Isolate Carrying
mcr-1
and
bla
NDM-5
Authors: Liu Lu , Feng Yu , Zhang Xiaoxia , McNally Alan , Zong Zhiyong 
Published: October 2017

ABSTRACT

A colistin- and carbapenem-resistant
Escherichia coli
clinical isolate was found to carry two plasmid-borne colistin-resistant genes,
mcr-1
and the newly identified
mcr-3
, and a carbapenemase gene,
bla
NDM-5
.
mcr-3
is a new variant (
mcr-3.5
) in the isolate and encodes three amino acid substitutions compared with the original MCR-3.
mcr-3
was carried by a Tn
As3
-like transposon on a self-transmissible IncP plasmid in the isolate, highlighting that
mcr-3
may have widely spread.
Transmission of Methicillin-Resistant Staphylococcus aureus to Human Volunteers Visiting a Swine Farm
Authors: Angen Øystein , Feld Louise , Larsen Jesper , Rostgaard Klaus , Skov Robert , Madsen Anne Mette , Larsen Anders Rhod 
Published: October 2017

ABSTRACT

Transmission of methicillin-resistant
Staphylococcus aureus
(MRSA) from animals to humans is of great concern due to the implications for human health and the health care system. The objective was to investigate the frequency and duration of MRSA carriage in human volunteers after a short-term exposure in a swine farm. The experimental study included 34 human volunteers staying 1 h in a MRSA-positive swine farm in four trials. In two of the trials, the influence of farm work involving pig contact was studied using a crossover design. The quantities of MRSA in nasal swabs, throat swabs, and air samples were measured at different time points and analyzed in relation to relevant covariates. This investigation showed that, overall, 94% of the volunteers acquired MRSA during the farm visit. Two hours after the volunteers left the stable, the nasal MRSA count had declined to unquantifiable levels in 95% of the samples. After 48 h, 94% of the volunteers were MRSA-negative. Nasal MRSA carriage was positively correlated to personal exposure to airborne MRSA and farm work involving pig contact and negatively correlated to smoking. No association was observed between MRSA carriage and face touching behavior, nasal methicillin-susceptible
Staphylococcus aureus
(MSSA) carriage, age, or gender. The increase in human MRSA carriage among the volunteers with pig contact seems to be dependent on the increased concentration of airborne MRSA of the surrounding air and not directly on physical contact with pigs. MRSA was not detected in any of the throat samples.

IMPORTANCE
The experimental approach made it possible to elucidate the contributions of airborne MRSA levels and farm work to nasal MRSA carriage in a swine farm. Short-term exposure to airborne MRSA poses a substantial risk for farm visitors to become nasal carriers, but the carriage is typically cleared within hours to a few days. The risk for short-term visitors to cause secondary transmissions of MRSA is most likely negligible due to the observed decline to unquantifiable levels in 95% of the nasal samples after only 2 h. The MRSA load in the nose was highly correlated to the amount of MRSA in the air and interventions to reduce the level of airborne MRSA or the use of face masks might consequently reduce nasal contamination.