bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cost‐effectiveness of questionnaires in preventing transfusion‐transmitted infections
Authors: de Kort Wim , van den Burg Peter , Geerligs Herman , Pasker‐de Jong Pieternel , Marijt‐van der Kreek Tanneke 
Published: July 2013

BackgroundThe cost‐effectiveness of the donor health questionnaire (DHQ) as a tool to assess donor eligibility has not been quantified. This study focused on cost‐effectiveness of the DHQ in preventing transfusion‐transmitted infections (TTIs).Study Design and MethodsData on whole blood donor eligibility assessments in the Netherlands in 2008 to 2010 were analyzed. Based on test results and epidemiologic data on TTIs, the number of donor visits in their window phase was calculated. Subsequently, the incremental cost‐effectiveness ratio (ICER) of the DHQ was calculated.ResultsThe overall annual deferral rate in the study period was 9.6% (9.3%‐10.0%). The annual deferral rate for TTI risk was 0.86% (0.82%‐0.89%). Taking into account the number of self‐deferrals, deferral rate for TTI risk in all donors was 1.90% (1.81%‐2.02%). The calculated annual numbers of prevented cases of TTI were hepatitis B, 0.142; hepatitis C, 0.010; human immunodeficiency virus, 0.016; and syphilis, 0.135. The annual costs for TTI risk–related eligibility assessments, deferrals, and substitutions were €84,807 (€55,193‐€123,811) for the blood establishment (BE) and €90,501 (€46,965‐€159,571) for deferred donors. Annual savings were €991 (€276‐€2325), while annual quality‐adjusted life‐years (QALYs) gained were 0.120 (0.059‐0.226). Hence, the ICER for the DHQ on preventing TTIs was €696,744 (€315,422‐€1,611,681) for BE costs only and €1,449,055 (€669,439‐€3,145,961) including costs for deferred donors.ConclusionThe DHQ enhances self‐selection and should not be abandoned. However, the DHQ is not a cost‐effective tool for further reducing TTIs. The high costs per case prevented and the small number of QALYs gained argue against maintaining deferral policy through the DHQ at the current level.
A Computational Investigation of Modified Intake Ports to Improve Scavenging in a Heavy-Duty Two-Cycle Diesel Engine
Authors: Dolak Jonathan , Bandyopadhyay Deep 
Published: July 2013

The objective of this research was to improve the scavenging process on a heavy-duty, two-cycle, medium speed, diesel engine (710 cubic inches of displacement per cylinder) under high load. It was desired to expel as much of the residual gases in the combustion chamber during the scavenging process, without having the fresh intake air escaping through the exhaust valves. This allowed a cooler intake charge with a higher oxygen concentration to be used. Having a cooler air intake charge was beneficial for emissions and performance. The power assembly configuration for the investigation was a two-cycle engine with intake ports around the bottom portion of the cylinder liner and four exhaust valves in the cylinder head. The main variable in this study was the axial location of every other intake port on the cylinder liner. When the axial location increased, this created pseudo longer intake timing. To keep the amount of trapped mass constant, the exhaust valves remained opened longer. The effectiveness of the scavenging process was estimated by the concentration of trapped oxygen (O2), carbon dioxide (CO2), and water vapor (H2O) along with the average temperature of the intake charge at the end of scavenging. The final part of the research explored each modified cylinder liner under full load, combustion operating conditions, while varying the injection timings. Soot, nitrogen oxides (NOx) and fuel consumption were also examined. A proprietary, multi-dimensional, computational fluid dynamic (CFD) code was used for the modeling work. Sculptor™, a commercial software package, was used to morph the cylinder liner.
The results showed that by increasing the axial location of the intake ports, a cooler intake charge with higher oxygen and lower carbon dioxide and water vapor concentrations resulted. This suggested more exhaust gases were expelled from the combustion chamber and replaced with fresh air. The rate of improvement slowed down after increasing the intake port axial location by 15.0 mm. In the next step, the compression and combustion process of the different port locations was studied. The cases with higher intake port axial locations were found to have lower pressure throughout the compression and power cycles. The temperature was lower for cases with elevated intake ports, until combustion started. The final part of the research studied the modified intake port cases under combustion simulation, while varying the injection timing. Next, the results showed an improvement in soot and fuel consumption with an increase in NOx for a given injection timing. However, while injection timing was varied, it was possible to improve NOx, soot, and fuel consumption simultaneously when compared to the baseline.
Managing the Transition Between Low Temperature Combustion and Conventional Diesel Combustion During a Load Change
Authors: Sarangi Asish K. , Garner Colin P. , McTaggart-Cowan Gordon P. , Davy Martin H. , Wahab Emad A. , Peckham Mark S. 
Published: July 2013

High-EGR diesel low temperature combustion breaks the traditional diesel NOx-PM trade-off, thereby facilitating ultra-low NOx emissions with simultaneously low smoke emissions. High-EGR LTC is currently limited to low and medium load and speed conditions. Therefore, in order to implement a high-EGR diesel LTC strategy in a passenger vehicle, a transition to conventional diesel operation is required when either a high load or high speed is demanded. This transition must be carefully managed to ensure smooth operation and to avoid excessive pollutant emissions—a task that is complicated by the markedly different response time-scales of the engine’s turbocharger, EGR, and fuelling systems.
This paper presents the results of a combination of numerical simulation and steady-state engine experiments that describe the performance and emissions of an automotive-sized 2 litre turbocharged diesel engine during a rapid transition from high-EGR LTC to conventional diesel operation. The effects of load change at constant engine speed during the Extra-Urban Drive Cycle (EUDC) part of the New European Drive Cycle (NEDC) are first evaluated using a one-dimensional engine simulation (Ricardo WAVE). The inputs to the model are; the initial and final fuelling quantities, the duration of the transient events, and the response of the engine’s control systems. The WAVE model outputs the intake manifold pressure and EGR level for each cycle during the transition.
The predicted intake pressure, EGR rate and the corresponding known injected fuel mass for each individual cycle are used to define a set of ‘pseudo-transient’ test conditions—matching the conditions encountered at discrete points within the modelled transient—for subsequent steady-state engine testing on a 0.51 litre AVL single cylinder diesel engine. These test conditions are established on the engine using independently controllable EGR and boost systems and the corresponding emissions (NOx, smoke, CO, and THC) and performance data (GISFC) were recorded. The experimental emissions and performance data are subsequently presented on a cycle-by-cycle basis. The results of this study provide significant insight into the combustion conditions that might be encountered during mode switching and their deleterious effect on emissions and performance. Strategies to mitigate these effects are examined.
Simultanous Transient Surface Temperature and Heat Flux Measurements in a Large Bore Two-Stroke Diesel Engine
Authors: Christiansen Caspar Ask , Mayer Stefan , Schramm Jesper 
Published: July 2013

Surface temperature measurements were performed in a large bore two-stroke diesel engine used for ship propulsion. A specially designed fast-response surface thermocouple was used together with an embedded standard K-type thermocouple to measure surface temperature and heat flux with high temporal resolution.
Heat flux calculations were carried out both analytically and numerically showing good agreement between the results. Measurements were carried out at three different engine load conditions (25%, 30% and 50% load) in one of the fuel atomizers in the cylinder head. Cyclic surface temperature variations of up to approximately 80 K with a peak temperature of 860 K were observed.
The magnitude of the perturbation of the temperature field due to the presence of the thermocouples was investigated by three dimensional CFD simulations.
HCCI Operability Limits: The Impact of Refinery Stream Gasoline Property Variation
Authors: Lacey Joshua S. , Sathasivam Sakthish R. , Filipi Zoran S. , Cannella William J. , Fuentes-Afflick Peter A. 
Published: July 2013

HCCI combustion is highly dependent on in-cylinder thermal conditions favorable to auto-ignition, for a given fuel. Fuels available at the pump can differ considerably in composition and auto-ignition chemistry, hence strategies intended to bring HCCI to market must account for the fuel variability.
To this end, a test matrix consisting of eight gasoline fuels composed of blends made solely from refinery streams was investigated in an experimental, single cylinder HCCI engine. The base compositions were largely representative of gasoline one would expect to find across the United States, although some of the fuels had slightly lower average octane values than the ASTM minimum specification of 87. All fuels had 10% ethanol by volume included in the blend. The properties of the fuels were varied according to research octane number (RON), sensitivity (S=RON−MON) and the volumetric fractions of aromatics and olefins.
For each fuel, a sweep of the fuelling was carried out at each speed from the level of instability to excessive ringing to determine the limits of HCCI operation. This was repeated for a range of speeds to determine the overall operability zone. The fuels were kept at a constant intake air temperature during these tests.
The variation of fuel properties brought about changes in the overall operating range of each fuel, as some fuels had more favorable low load limits, whereas others enabled more benefit at the high load limit. The extent to which the combustion event changed from the low load limit to the high load limit was examined as well, to provide a relative criterion indicating the sensitivity of HCCI range to particular fuel properties.
Effects of a Low Octane Gasoline Blended Fuel on NVO Enabled HCCI Load Limit, Combustion Phasing and Burn Duration
Authors: Hagen Luke M. , Manofsky Olesky Laura , Bohac Stanislav V. , Lavoie George , Assanis Dennis 
Published: July 2013

Homogeneous Charge Compression Ignition (HCCI) combustion allows for the use of fuels with octane requirements below that of spark-ignited engines. A reference gasoline was compared with iso-octane and a low octane blend of gasoline and 40% n-heptane, NH40. Experiments were conducted on a single cylinder engine operating with negative valve overlap (NVO). The fuel flow rate per cycle was compensated based on the lower heating value to maintain a constant energy addition across fuels.
Iso-octane and gasoline demonstrated similar maximum load, achieving a gross IMEPg of ∼430 kPa, whereas the NH40 demonstrated an increased IMEPg of ∼ 460kPa. The NH40 could be operated at a later phasing compared with the higher octane fuels, and exhibited a shorter burn duration at a given fueling rate and phasing. These results could be due to compositional differences, as NH40 required less NVO compared to iso-octane and gasoline, leading to less thermal and compositional stratification, as well as a higher O2 concentration and less residual gas. Additionally, the NH40 fuel demonstrated a higher intermediate temperature heat release than the higher octane fuels, potentially contributing to the shorter burn duration. Overall, these results demonstrate clear benefits to NVO enabled HCCI combustion with low octane fuels.
Fundamental Study of Spray and Partially Premixed Combustion of Methane/Air Mixture
Authors: Askari Omid , Metghalchi Hameed , Moghaddas Ali , Hannani Siamak Kazemzadeh , Ebrahimi Reza 
Published: July 2013

This study presents fundamentals of spray and partially premixed combustion characteristics of directly injected methane inside a constant volume combustion chamber (CVCC). The constant volume vessel is a cylinder with inside diameter of 135 mm and inside height of 135 mm. Two end of the vessel are equipped with optical windows. A high speed complementary metal oxide semiconductor (CMOS) camera capable of capturing pictures up to 40,000 frames per second is used to observe flow conditions inside the chamber. The injected fuel jet generates turbulence in the vessel and forms a turbulent heterogeneous fuel–air mixture in the vessel, similar to that in a compressed natural gas (CNG) direct injection engine. The fuel–air mixture is ignited by centrally located electrodes at a given spark delay timing of 1, 40, 75 and 110 milliseconds after fuel injection has been completed to reflect different turbulence intensities. For comparative study, by increasing the spark delay timing to five minutes, a homogeneous premixed mixture is also prepared in the vessel which provides information on laminar homogeneous mixture combustion.
Spray development and characterization including spray tip penetration, spray cone angle and overall equivalence ratio were investigated under 30–90 bar fuel pressures and 1–5 bar chamber pressure. Flame propagation images and combustion characteristics were determined via pressure-derived parameters and analyzed at a fuel pressure of 90 bar and a chamber pressure of 1 bar at different stratification ratios (from 0% to 100%) at overall equivalence ratios of 0.6, 0.8 and 1.0. Shorter combustion duration and higher combustion pressure were observed in direct injection-type combustion at all fuel air equivalence ratios compared to those of homogenous combustion.
Piston Ring Load Carrying Capacity: Influence of Cross-Hatching Parameters
Authors: Bouassida H. , Biboulet N. , Sainsot P. , Lubrecht A. A. 
Published: July 2013

Energy and environment are of major concern in internal combustion engine component design. The piston ring-cylinder liner (PRCL) contact plays an essential part in design and is highlighted in this study. In fact, the rings ensure the sealing property, reducing the environmental impact by avoiding lubricant contamination (blow-by) and lubricant consumption. Unfortunately, when sealing, the rings generate between 11 to 24% of the friction losses in an internal combustion engine [1], thus reducing the energy efficiency of the engine.
The cylinder liner surface features a special micro-geometry, a classical one is the cross-hatching pattern, obtained by honing. This texturing acts as a micro-bearing, oil reservoir and debris trap. Understanding the influence of texture parameters as groove depth and width or angle, will allow tribological improvements of the PRCL contact.
The 2D transient Reynolds equation has to be solved for this kind of surface. The statistical method using the Patir and Cheng [2] flow factors is widely used. This approach lumps the different components of the surface (grooves and plateaux) and does not consider the roughness directionality. Methods decoupling both components, like the homogenization method [3] are also used. Another alternative is to use a deterministic model on measured surfaces, but this is a “hugely” expensive approach. Multigrid methods [4] are used to drastically reduce the calculational cost.
The aim of the current study is to facilitate the understanding of measured surface calculations. Hence, analytical surfaces are used. They allow a flexible handling of the cross-hatching parameters. The plateaux are perfectly smooth and the grooves are sinusoidally shaped. The top ring is modelled using a parabolic profile. Periodic boundary conditions are used in the orthoradial direction and zero pressure conditions (Dirichlet) in the axial direction.
To investigate the effect of different parameters, various imposed film thicknesses are applied and the mean load carrying capacity (LCC) over time is calculated. When representing the LCC corresponding to each parameter compared to the smooth LCC, as a function of the logarithm of the minimum film thickness, the curves are quite linear for small values of the film thickness and then for larger values they converge to 1.
Influence of Coating Thickness and Substrate Elasticity on the Tribological Performance of PEEK Coatings
Authors: Wang Yuanyuan , Terrell Elon J. 
Published: July 2013

When a material is subjected to repeated sliding contact, a surface fatigue and crack nucleation may occur on its surface. This damage weakens the material and can lead to debris formation. In many practical engineering assemblies, a thin PEEK (poly-ether-ether-ketone) coating is applied to reduce the damage, since PEEK exhibits wear resistance, corrosion resistance self-lubricating capacity and is lightweight. However, little is known about the effect of coating thickness on the plastic deformation, residual stresses and energy dissipation of PEEK when placed under sliding load. Moreover, the effect of substrate rigidity on coating stresses and deformation under sliding load are also under-researched. Having such knowledge is of significant importance in order to reduce damage of engineering parts and extend their lifetime.
In this study, the effects of PEEK coating thickness and substrate elasticity were analyzed using a 3D ball-on-flat finite element model as well as experimental analysis using a linear reciprocating tribometer. The experimental tests were performed with samples that incorporated PEEK coatings of various thicknesses on alumina and steel substrates. It was found that under a constant normal load, stresses, strain and energy dissipation were sensitive to both substrate material and coating thickness. It is shown from both simulation and experiment, the optimum combination, within the range the experiments were conducted, for minimizing residual stress and possible fatigue damage was an alumina substrate with 35μm PEEK coating thickness.
Mechanisms of Entrapment and Release of Fluid Droplets From Nano-Scale Surface Features
Authors: Chong William , Teodorescu Mircea , Martini Ashlie , Rahnejat Homer 
Published: July 2013

Engineering surfaces are never perfectly flat. They contain micro and nano-scale features on multiple length scales. Predicting the amount of fluid trapped in these minute surface crevices and its controlled release could benefit a variety of practical applications. In a sliding contact, the released fluid could create an ultra-thin film, reducing the direct contact and consequently the boundary friction. Transdermal patches are the least invasive of available subcutaneous drug delivery techniques. The drug is stored in a micro-reservoir and it is released to the skin either through a permeable membrane or through a series of micro needles.
The aim of the current paper represents the first attempt to investigate whether a modeling approach encompassing two complementary simulation techniques in an integrated framework can be used to predict the volume of fluid stored in a nano-scale surface feature. Molecular dynamics (MD) simulation could provide accurate modeling of fluid behavior at nano-scale, and statistical mechanics (SM) could provide a fast prediction.
Heavy Gauge UOE Pipe With Improved Compressive Strength for Offshore Pipeline
Authors: Ishikawa Nobuyuki , Sueyoshi Hitoshi , Nishimura Kimihiro , Yamamoto Osamu , Tanizawa Akihiko , Kiyoto Yasumitsu , Naganuma Daisuke 
Published: July 2013

Offshore gas pipeline development has been expanding toward deeper water region that requires pipes to have strong resistance against collapse by external pressure. Collapse pressure is mainly dominated by pipe roundness and compressive strength. In order to improve compressive strength, it is quite important to understand the Bauschinger effect caused by cyclic deformation during pipe forming. Compressive strength is reduced by the Bauschinger effect since compression in the circumferential direction is applied after the pipe expansion. Therefore, prevention of Bauschinger effect is an important issue for improving compressive strength of pipes.
In this paper, the effect of microstructure on the Bauschinger effect was investigated. It was proved that microstructure that consists of a hard second phase shows a large strength reduction in reverse loading, since a mixed microstructure with soft phase and hard phase enhances the Bauschinger effect. In order to obtain homogeneous bainitic microstructure, advanced plate production technology, where heat treatment on-line process (HOP) is applied after accelerated cooling, was developed. The steel produced by HOP process exhibits a fine bainitic microstructure with very low amount of hard second phase such as MA constituent. It was demonstrated that the trial produced pipe with HOP process has a higher compressive strength than conventional pipes.
In addition to the fundamental study on compressive strength, further investigations were conducted to optimize other material properties for offshore linepipe, such as DWTT property, resistance to hydrogen induced cracking and HAZ toughness to comply with DNV requirements. Production tests of Grade X65 linepipe with the 38mm WT and 876mm OD was carried out. Material and mechanical properties of these heavy gauge linepipes were introduced.
A Comparison of Double Block and Bleed Technologies
Authors: Bowie Angus 
Published: July 2013

Double Block and Bleed is a term often used in the oil and gas industry to define a level of isolation sufficient to perform maintenance activities. The true definition relates to incumbent valves providing two proven levels of isolation against the outboard pressure to permit breaching of containment in the isolated pipe. This paper assesses how temporary isolation devices can provide equivalent isolation where incumbent valves do not exist at appropriate locations in the system. It reviews the different interpretations of Double Block and Bleed used within the industry and compares how different isolation devices are assessed in relation to the level of isolation they provide.
It will reference several examples from around the world of where temporary isolation devices have been used to replace valves and perform repairs in trunk pipelines without depressurising the whole pipeline. It will also cover examples of isolating live process pipe to perform maintenance activities outside plant shutdown.