bluuebunny/crossref_metadata_2025 huggingface dataset:
Central nesfatin-1-expressing neurons are sensitive to peripheral inflammatory stimulus
Authors: Bonnet Marion S , Pecchi Emilie , Trouslard Jérôme , Jean André , Dallaporta Michel , Troadec Jean-Denis
Published: September 2009

Recently, a novel factor with anorexigenic properties was identified and called nesfatin-1. This protein (82 aac) is not only expressed in peripheral organs but it is also found in neurons located in specific structures including the hypothalamus and the brainstem, two sites strongly involved in food intake regulation. Here, we studied whether some of the neurons that become activated following an injection of an anorectic dose of lipopolysaccharides (LPS) exhibit a nesfatin-1 phenotype. To this end, we used double immunohistochemistry to target the expression of the immediate-early gene c-fos and of nesfatin-1 on coronal frozen sections of the rat brain. The number of c-Fos+/nesfatin-1+ neurons was evaluated in the immunosensitive structures reported to contain nesfatin-1 neurons; i.e. paraventricular hypothalamic nucleus (PVN), supraoptic nucleus (SON), arcuate nucleus (ARC) and nucleus of the solitary tract (NTS). LPS strongly increased the number of c-Fos+/nesfatin-1+ neurons in the PVN, SON and NTS, and to a lesser extent in the ARC. Triple labeling showed that a portion of the nesfatin-1 neurons activated in response to LPS within the NTS are catecholaminergic since they co-express tyrosine hydroxylase (TH). Our data therefore indicate that a portion of nesfatin-1 neurons of both the hypothalamus and brainstem are sensitive to peripheral inflammatory signals, and provide the first clues suggesting that centrally released nesfatin-1 may contribute to the neural mechanisms leading to endotoxaemic anorexia.
Short-term effects of air pollution: a panel study of blood markers in patients with chronic pulmonary disease
Authors: Hildebrandt Katharina , Rückerl Regina , Koenig Wolfgang , Schneider Alexandra , Pitz Mike , Heinrich Joachim , Marder Victor , Frampton Mark , Oberdörster Günter , Wichmann H Erich , Peters Annette
Published: September 2009

Background

Growing evidence indicates that ambient air pollution is associated with exacerbation of chronic diseases like chronic pulmonary disease. A prospective panel study was conducted to investigate short-term changes of blood markers of inflammation and coagulation in response to daily changes in air pollution in Erfurt, Germany. 12 clinical visits were scheduled and blood parameters were measured in 38 male patients with chronic pulmonary disease during winter 2001/2002. Additive mixed models with random patient intercept were applied, adjusting for trend, weekday, and meteorological parameters. Hourly data on ultrafine particles (UFP, 0.01-0.1 μm), accumulation mode particles (ACP, 0.1-1.0 μm), PM10 (particulate matter <10 μm in diameter), elemental (EC) and organic carbon (OC), gaseous pollutants (nitrogen monoxide [NO], nitrogen dioxide [NO2], carbon monoxide [CO], and sulphur dioxide [SO2]) were collected at a central monitoring site and meteorological data were received from an official network. For each person and visit the individual 24-hour average of pollutants immediately preceding the blood withdrawal (lag 0) up to day 5 (lag1-4) and 5-day running means were calculated.

Results

Increased levels of fibrinogen were observed for an increase in one interquartile range of UFP, PM10, EC, OC, CO, and NO revealing the strongest effect for lag 3. E-selectin increased in association with ACP and PM10 with a delay of one day. The ACP effect was also seen with the 5-day-mean. The pattern found for D-dimer was inconsistent. Prothrombin fragment 1+2 decreased with lag 4 consistently for all particulate pollutants. Von Willebrand factor antigen (vWF) showed a consistent decrease in association with almost all air pollutants with all lags except for lag 0. No associations were found for C-reactive protein, soluble intercellular adhesion molecule 1, serum amyloid A and factor VII.

Conclusion

These results suggest that elevated concentrations of air pollution are associated with changes in some blood markers of inflammation and coagulation in patients with chronic pulmonary disease. The clinical implications of these findings need further investigation.
Micro-scaled high-throughput digestion of plant tissue samples for multi-elemental analysis
Authors: Hansen Thomas H , Laursen Kristian H , Persson Daniel P , Pedas Pai , Husted Søren , Schjoerring Jan K
Published: September 2009

Background

Quantitative multi-elemental analysis by inductively coupled plasma (ICP) spectrometry depends on a complete digestion of solid samples. However, fast and thorough sample digestion is a challenging analytical task which constitutes a bottleneck in modern multi-elemental analysis. Additional obstacles may be that sample quantities are limited and elemental concentrations low. In such cases, digestion in small volumes with minimum dilution and contamination is required in order to obtain high accuracy data.

Results

We have developed a micro-scaled microwave digestion procedure and optimized it for accurate elemental profiling of plant materials (1-20 mg dry weight). A commercially available 64-position rotor with 5 ml disposable glass vials, originally designed for microwave-based parallel organic synthesis, was used as a platform for the digestion. The novel micro-scaled method was successfully validated by the use of various certified reference materials (CRM) with matrices rich in starch, lipid or protein. When the micro-scaled digestion procedure was applied on single rice grains or small batches of Arabidopsis seeds (1 mg, corresponding to approximately 50 seeds), the obtained elemental profiles closely matched those obtained by conventional analysis using digestion in large volume vessels. Accumulated elemental contents derived from separate analyses of rice grain fractions (aleurone, embryo and endosperm) closely matched the total content obtained by analysis of the whole rice grain.

Conclusion

A high-throughput micro-scaled method has been developed which enables digestion of small quantities of plant samples for subsequent elemental profiling by ICP-spectrometry. The method constitutes a valuable tool for screening of mutants and transformants. In addition, the method facilitates studies of the distribution of essential trace elements between and within plant organs which is relevant for, e.g., breeding programmes aiming at improvement of the micronutrient density in edible plant parts. Compared to existing vial-in-vial systems, the new method developed here represents a significant methodological advancement in terms of higher capacity, reduced labour consumption, lower material costs, less contamination and, as a consequence, improved analytical accuracy following micro-scaled digestion of plant samples.
Leadership is the essential non-technical skill in the trauma team - results of a qualitative study
Authors: Hjortdahl Magnus , Ringen Amund H , Naess Anne-Cathrine , Wisborg Torben
Published: September 2009

Background

Trauma is the leading cause of death for young people in Norway. Studies indicate that several of these deaths are avoidable if the patient receives correct initial treatment. The trauma team is responsible for initial hospital treatment of traumatized patients, and team members have previously reported that non-technical skills as communication, leadership and cooperation are the major challenges. Better team function could improve patient outcome. The aim of this study was to obtain a deeper understanding of which non-technical skills are important to members of the trauma team during initial examination and treatment of trauma patients.

Methods

Twelve semi-structured interviews were conducted at four different hospitals of various sizes and with different trauma load. At each hospital a nurse, an anaesthesiologist and a team leader (surgeon) were interviewed. The conversations were transcribed and analyzed using systematic text condensation according to the principles of Giorgi's phenomenological analysis as modified by Malterud.

Results and conclusion

Leadership was perceived as an essential component in trauma management. The ideal leader should be an experienced surgeon, have extensive knowledge of trauma care, communicate clearly and radiate confidence. Team leaders were reported to have little trauma experience, and the team leaders interviewed requested more guidance and supervision. The need for better training of trauma teams and especially team leaders requires further investigation and action.
Duration of red blood cell storage is associated with increased incidence of deep vein thrombosis and in hospital mortality in patients with traumatic injuries
Authors: Spinella Philip C , Carroll Christopher L , Staff Ilene , Gross Ronald , Mc Quay Jacqueline , Keibel Lauren , Wade Charles E , Holcomb John B
Published: September 2009

Introduction

In critically ill patients the relationship between the storage age of red blood cells (RBCs) transfused and outcomes are controversial. To determine if duration of RBC storage is associated with adverse outcomes we studied critically ill trauma patients requiring transfusion.

Methods

This retrospective cohort study included patients with traumatic injuries transfused ≥5 RBC units. Patients transfused ≥ 1 unit of RBCs with a maximum storage age of up to 27 days were compared with those transfused 1 or more RBC units with a maximum storage age of ≥ 28 days. These study groups were also matched by RBC amount (+/- 1 unit) transfused. Primary outcomes were deep vein thrombosis and in-hospital mortality.

Results

Two hundred and two patients were studied with 101 in both decreased and increased RBC age groups. No differences in admission vital signs, laboratory values, use of DVT prophylaxis, blood products or Injury Severity Scores were measured between study groups. In the decreased compared with increased RBC storage age groups, deep vein thrombosis occurred in 16.7% vs 34.5%, (P = 0.006), and mortality was 13.9% vs 26.7%, (P = 0.02), respectively. Patients transfused RBCs of increased storage age had an independent association with mortality, OR (95% CI), 4.0 (1.34 - 11.61), (P = 0.01), and had an increased incidence of death from multi-organ failure compared with the decreased RBC age group, 16% vs 7%, respectively, (P = 0.037).

Conclusions

In trauma patients transfused ≥5 units of RBCs, transfusion of RBCs ≥ 28 days of storage may be associated with deep vein thrombosis and death from multi-organ failure.
Murderabilia Inc.: Where the First Amendment Fails Academic Freedom
Authors: Nelson Samuel P. , Prendergast Catherine
Published: September 2009

The commonplace justification of academic freedom, described in terms of professional norms and practices of the professoriate, often cites advancing the public interest in knowledge creation as a key basis for academic freedom. Yet the public's role remains underspecified, its interests loosely defined, and it is increasingly imagined as opposite the professoriate in this justification. Using the example of the U.S. government's effort to control and ultimately destroy the archived papers of convicted murderer and former professor Theodore Kaczynski through a “murderabilia” auction, we explore the relationship between the public's freedom of inquiry and access to information, on the one hand, and academic freedom of the professoriate, on the other. We argue that the public's broad, yet poorly recognized freedom of inquiry under the First Amendment is in some ways analogous to the academic freedom of faculty described by application of professional norms. While we seek to clarify the boundary between these freedoms, we argue that they can be mutually reinforcing to the benefit of both academics and the broader public. We conclude that more is to be gained by such rethinking of the relationship of the public to academic freedom than by the current attempts to refine the professoriate's position in the corporate hierarchy of the university.
Accelerated durability assessment of motorcycle components in real-time simulation testing
Authors: Lin K-Y , Hwang J-R , Chang J-M
Published: September 2009

The rapid development of the vehicle industry has made reducing product development time a major concern. This study seeks to identify a suitable accelerated approach to durability analysis for motorcycle components. This investigation involves field data acquisition, laboratory road load simulation, accelerated durability testing, and fatigue life prediction. Two methods, ‘strain range editing technique’ and ‘racetrack editing technique’, were applied to edit field strain histories for accelerated durability tests. Furthermore, four methods, including the ‘S–N approach with fatigue property of base metal’, ‘Eurocode 3 approach’, ‘BS 5400 approach’, and ‘BS 5400 approach with Gurney thickness modification’, were employed to assess fatigue life. Three road types and four damage levels were also used. The results demonstrated that the ‘BS 5400 approach with Gurney thickness modification’ is a suitable method of assessing the durability of welded motorcycle components when the fatigue properties of critical points are not available. Both the ‘strain range editing technique’ and ‘racetrack editing technique’ can effectively edit strain histories with the expected quantity of fatigue damage, and demonstrate satisfactory agreement between the experimental data and predicted data.
Modelling engine and exhaust temperatures of a mono-fuelled turbocharged compressed-natural-gas engine during warm-up
Authors: Röth J A , Guzzella L
Published: September 2009

A promising way to reduce the carbon dioxide emissions of vehicles is the use of engines fuelled only by compressed natural gas (CNG). However, even with CNG, restrictions on pollutants such as methane and non-methane hydrocarbons must be complied with. In a modern spark ignition (SI) engine, most of the pollutants are produced during the cold start before the catalytic converter reaches its light-off temperature. To avoid costly problems late in the development phase, it is reasonable to assess the functionality of the exhaust system as a whole, and the light-off behaviour of the catalytic converter in particular, as early as possible using simulation. Today's state-of-the-art catalytic converter simulation tools require the temperature signal upstream of the catalytic converter as input. This necessitates an easily applicable simulation tool of the exhaust temperature that takes the engine warm-up into account.

This paper presents a new physics-based model for the estimation of the engine and exhaust temperatures for a CNG-fuelled SI engine during warm-up. A new mean value model for the combustion wall heat transfer and also a lumped-parameter consideration of the cooling fluid are presented. In addition, existing methods for engine modelling are adapted to account for engine warm-up. Based on measurements performed on a special test bench assembly, the most important physical effects occurring in this phase are identified. Various experiments for parameterization and validation of the model are carried out. Tests for all relevant engine operating variations confirm a good correlation between the model and measurement results.
Study of spray impingement and a squish combustion system for diesel engines
Authors: Wei S-L , Long W-Q , Feng L-Y , Du B-G , Leng X-Y
Published: September 2009

In order to improve fuel/air mixture homogeneity and enhance air motion in the combustion chamber, a new spray impingement and squish combustion system (SISCS) is developed. The mixture formation and combustion processes in three different combustion chambers are simulated using the AVL-FIRE code. Simulation results show that the passage width has great influence on combustion and emissions. Compared with the original engine the NO and soot emissions can be reduced by using the combustion chamber of the case B.
Some torsional stiffness and damping characteristics of a small pneumatic tyre and the implications for powertrain dynamics
Authors: Guzzomi A L , Sharman A , Stone B J
Published: September 2009

Torsional vibration modelling of powertrains is hindered by the lack of understanding of tyre low-frequency torsional stiffness and damping characteristics. Torsional here means rotation about the wheel (spin) axis so that the rotation of the wheel hub is different from that of the periphery of the tyre. This paper explains a simple, practical test rig design that can be used to determine a tyre's torsional characteristics via simple modelling. The model assumes a complex stiffness that allows the damping type to be determined as a function of the frequency. The measurement of some torsional stiffness and damping characteristics of a small pneumatic tyre while under load and rolling is presented. The tyre was excited torsionally and, from the results obtained, the tyre's torsional stiffness and damping characteristics were calculated. The investigations were concerned with the low-frequency characteristics. It was found that there was a large torsional vibration associated with the tread pattern. Over the frequency range tested (10–50Hz), it was found that the damping is more accurately represented as hysteretic and not viscous when lightly loaded. The effects of rotational speed, preload, and inflation pressure on the stiffness and damping were also investigated. The damping type for the tyre (hysteretic or viscous) was found to vary depending on the loading and excitation. Tyre properties were then included in a lumped-inertia, frequency-domain powertrain model and the steady-state response predicted. The results indicated that the viscous or hysteretic damping assumption has significant effects on the predicted frequency response of the powertrain. The need for further studies investigating the damping characteristics of automotive tyres in torsion is therefore recommended.
Potential for expanders in a mobile carbon dioxide air-conditioning system
Authors: Salim M M
Published: September 2009

Three possible automotive CO2 air-conditioning system configurations were simulated over the full range of vehicle operating conditions. These include a baseline cycle with an internal heat exchanger (IHX), an expander cycle, which is simply a baseline cycle without an IHX and with a turbine replacing the expansion valve, and finally an expander cycle with an IHX. It was found that the highest coefficient of performance was achieved using the expander cycle, with 30–45 per cent improvement over the baseline cycle, followed by the expander cycle with the IHX, and then the baseline cycle. However, when the capacity was investigated, the expander cycle resulted in the lowest capacity for all gas cooler refrigerant outlet temperatures. The cycle with the IHX and the work-recovering expander had the highest capacity followed by the baseline cycle. Based on the above, the IHX is a fundamental component in the CO2 systems and cannot be simply eliminated if an expander is used in the system. It was also found through simulation that up to 57 per cent of compressor work can be recovered in cycle 2, and 30 per cent in cycle 3 using an expander, compared with only 18 per cent in current production R-134a systems.
Distributed vehicle body electric/electronic system architecture with central coordination control
Authors: Gu Z-M , Yang D-G , Zhang X-F , Lu L , Li K-Q , Lian X-M
Published: September 2009

The conventional vehicle electric/electronic system architecture has become an obstacle of the booming development of in-vehicle electric and electronic devices. The surging number of these devices and the runup of the information exchange requirement among the devices call for a brand new system architecture.

In this paper, a completely distributed electric/electronic system architecture with a centralized coordinator is introduced. The new architecture concept features a set of hierarchy on-site serial buses together with a digitalized power supply network coordinated by a central controller. The basic functionality and diagnosis of all the in-vehicle electric devices are implemented as digitalized nodes with unified connection interface in the network, which execute commands and share information with the central coordinator.

The new architecture facilitates the information exchange, minimizes the cost and effort of vehicle harness, and reserves the configurability and expandability. The distributed structure with twin backup central coordinators ensures the system reliability.
Hierarchical fuzzy control for engine isolation via magnetorheological fluid mounts
Authors: Li R , Chen W-M , Liao C-R
Published: September 2009

An engine isolation system via tuneable damping mounts can contribute to enhanced automobile performance. In this study, a magnetorheological fluids (MRF) mount in squeeze mode for engine isolation is proposed and its damping characteristics are analysed. Based on an engine isolation dynamic model with three degrees of freedom, a hierarchical fuzzy control (HFC) system is proposed to decrease the vertical vibration force and roll moment transmitted from an engine to a foundation. On the control level, a fuzzy controller is designed to isolate the engine vertical vibration. On the coordination level, fuzzy reasoning is adopted to realize a coordination strategy for tuning the damping of each MRF mount in order to minimize the transmitted torque. The simulation is developed in MATLAB, and the experimental isolation system for an actual engine is built in the laboratory. With wide excitation frequency inputs under different operation conditions, studies on different engine mount isolation systems are carried out. Simulation results indicate that MRF mounts using the HFC strategy have more advantages than passive elastomeric mounts or hydraulic mounts, especially in the low-frequency range. Laboratory results confirm that the engine HFC system via MRF mounts performs markedly better than the passive mount system. The absolute force transmissibility ratio and torque transmissibility ratio are reduced to lower than 0.3 in actual complex excitation, which is very significant for an improvement in noise, vibration, and harshness.
Rescaled range analysis of service load data
Authors: Rathanraj K J , Srividya A , Verma A K , Raman R , Mannikar A V , Pankhawala V A
Published: September 2009

Recent advances in data acquisition, storing, and recording technology are allowing increasingly detailed samplings of actual customer usage of product. Because of this, laboratories are coming forward to use the actual road data rather than simulated data or data collected from the proving ground. This research work is an attempt to find a representative length of data (short-term data) from the large-distance data (long-term data). For any particular class of vehicle, finding the short-term data, which are representative of long-term data, will avoid the collection of large-distance data in the future.

In this paper, using the Hurst methodology an attempt have been made to find the short-term data that have to be collected, so as to be representative of the long-term data. In this study, data have been collected both on the proving ground as well as on an actual road for a distance of 1700km on a light commercial vehicle. It has been seen from the Hurst exponent that, collecting data for an actual road length of about 200km would give a representation for an actual road length of 1000km.
The impact of biodiesel blend ratio on vehicle performance and emissions
Authors: Bannister C D , Hawley J G , Ali H M , Chuck C J , Price P , Chrysafi S S , Brown A , Pickford W
Published: September 2009

Biodiesel is synthesized via the transesterification of triglycerides contained within vegetable, animal, or waste oils. First-generation biofuels are not the solution to global transport energy needs; however, biodiesel does have a role to play in reducing greenhouse gas emissions from the transport sector, so long as necessary production can be achieved in a sustainable manner without negative impact on plant and animal biodiversity. The biodiesel content within diesel sold to consumers is set to increase in the future, with implications on vehicle fuel consumption, emissions, and base engine durability. This study examines the effects of increasing the biodiesel blend ratio on the performance and emissions of a production vehicle equipped with a common-rail direct-injection diesel engine, evaluated on a chassis rolls dynamometer, at various ambient temperatures. Results obtained show that reductions in engine-out carbon monoxide and hydrocarbon emissions do not always translate to lower tailpipe emissions as reduced exhaust gas temperatures at higher blend ratios lead to reduced catalyst conversion efficiencies and higher total cycle emissions. Catalyst conversion efficiencies for carbon monoxide and hydrocarbons over the New European Drive Cycle (NEDC) are reduced by 9–19 per cent (depending on the ambient temperature) for a 50:50 blend (B50) compared with the petroleum diesel (B0) baseline. Increasing the blend ratio caused a linear decrease in the vehicle's maximum tractive force. This reduction was of the order of 5 per cent for a B50 blend at low vehicle speeds and 6–10 per cent at higher speeds, which is greater than would be expected on the basis of the differences in calorific values. Over the NEDC, the fuel consumption was found to increase with increasing blend ratio.
On the non-linear behaviour of motorcycle shock absorbers
Authors: Cossalter V , Doria A , Pegoraro R , Trombetta L
Published: September 2009

Motorcycle shock absorbers exhibit a non-linear behaviour characterized by hysteresis in the force—velocity diagram. The presence of hysteresis is the main obstacle in the identification of parameters and the development of computationally efficient shock absorber models. Gas compression, oil compressibility, mechanical compliance of chambers, and oil inertia are the most important causes of hysteresis. This paper deals with experimental research carried out on a twin-tube shock absorber equipped with pressure gauges in the chambers. A physical model is developed to explain the behaviour of the shock absorber from the measured pressures. The relevance of the various non-linear phenomena is discussed. The friction, hydraulic, and compliance parameters are identified from the measurements. The mathematical model fitted with the identified parameters is able to predict with accuracy the force generated by the shock absorber.
Computational analysis of the lean-burn direct-injection jet ignition hydrogen engine
Authors: Boretti A , Watson H , Tempia A
Published: September 2009

This paper presents a new in-cylinder mixture preparation and ignition system for various gaseous fuels including hydrogen. The system consists of a centrally located direct-injection (DI) injector and a jet ignition (JI) device for combustion of the main chamber (MC) mixture. The fuel is injected in the MC with a new-generation, fast-actuating, high-pressure, high-flowrate DI injector capable of injection shaping and multiple events. This injector produces a bulk lean stratified mixture. The JI system uses a second DI injector to inject a small amount of fuel in a small pre-chamber (PC). A spark plug then ignites a slightly rich mixture. The MC mixture is then bulk ignited through multiple jets of hot reacting gases. Bulk ignition and combustion of the lean jet-controlled stratified MC mixture resulting from coupling DI with JI makes it possible to burn MC mixtures with fuel-to-air equivalence ratios reducing almost to zero for a throttleless control of load diesel-like and high efficiencies over almost the full range of loads. Computations are performed with hydrogen as the PC and MC fuel.
Modelling, control, and hardware-in-the-loop simulation of an automated manual transmission
Authors: Song X-Y , Sun Z-X , Yang X-J , Zhu G-M
Published: September 2009

To enable a realistic automated manual transmission (AMT) system performance evaluation and rapid prototyping, this paper focuses on constructing a practical Simulink model and a hardware-in-the-loop (HIL) real-time simulation. The working principle and dynamic characteristics of the AMT system are first explored. The driveline, the engine control, and the dry clutch are modelled and analysed. In particular, a dynamic model for the hydraulic clutch actuator that is currently used in the actual transmissions is developed. To evaluate the performance and operation characteristics of the AMT system, the control methodology to ensure desirable performance is studied. The gearshift control logic and the proportional—integral—derivative-based clutch control are analysed and implemented. Based on the dynamic model and the controller, a Simulink model is developed and implemented into an HIL real-time simulator to enable rapid prototyping. In addition, to realize an energy-efficient and smooth clutch engagement, the possibility of using the dynamic programming method to generate the optimal clutch and engine torque control inputs is investigated as well. In particular, the controllability of the AMT system is studied to determine the number of control inputs necessary for optimal control. To this end, the simulation and experiment results in the HIL environment are presented.
Hydrocarbon impact on NOx survivability during diesel low-temperature combustion cycles
Authors: Zheng M , Asad U , Han X , Wang M , Reader G T
Published: September 2009

Low-temperature combustion (LTC) cycles are inherently inclined to produce higher amounts of combustibles because the burning of a homogeneous cylinder charge that is lean and/or exhaust gas diluted is closer to the non-combustion regions (flame-out limits). However, the impact of the hydrocarbons produced during the LTC cycles on the attainment of ultra-low levels of nitrogen oxides (NO x) is less understood, and it is unclear whether the hydrocarbon species are a precursor to the ultra-low NO x and also contribute in part to the NO x reduction. Therefore, the impact of the hydrocarbon emissions on the NO x emission of the LTC cycles has been empirically investigated on a number of common-rail diesel engine platforms of high compression ratios. The empirical studies have been conducted under independently controlled exhaust gas recirculation, intake boost, and exhaust back pressure. The survivability of NO x under the compression and combustion processes has been presented in the context of the quasi-steady exhaust NO x and the effect of the hydrocarbons on the NO x survivability has been quantified. The chemical impact of the hydrocarbon species on the NO x emission under LTC cycles has been examined with crank-angle-resolved in-cylinder sampling techniques and fast-response emission analysers. Furthermore, the ratio of nitric oxide to nitrogen dioxide under the LTC cycles has been quantified and compared with that in conventional diesel combustion. This paper intends to identify the major impacts of the hydrocarbons on the NO x emission of diesel LTC cycles.
Enhanced control performance of a piezoelectric—hydraulic pump actuator for automotive transmission shift control
Authors: Kim G W , Wang K W
Published: September 2009

In this research, a piezoelectric—hydraulic pump (PHP) actuator is synthesized for an automatic transmission (AT) test bed to demonstrate its potentials as a controllable power-by-wire actuator. This research expands from the previous investigations by enhancing the control performance of the PHP actuator developed for AT and bringing the study to the system level. Actuation force-tracking control using an on-site force transducer is proposed and a fill volume control strategy utilizing the AT turbine acceleration information is explored. The system level evaluation of shift performance is performed to demonstrate the effectiveness of the proposed enhancements through a hardware-in-the-loop simulation environment.
Isolating incipient sensor faults and system reconfiguration in a flight control actuation system
Authors: Jayakumar M , Das B B
Published: September 2009

This article presents the application of the additive form of the unscented Kalman filter (UKF-A) for the detection and isolation of incipient sensor faults in an electromechanical flight control actuation system. The detailed model of the actuator including mounting structure stiffness, load dynamics, compensators, power amplifier, and friction non-linearity is considered. The scheme utilizes the analytical redundancy that exists in the system between the linear actuator position, motor shaft angular velocity, and motor current for the diagnosis of incipient sensor faults in the system. Fault diagnosis is carried out using a single UKF-A, which is driven by the motor shaft velocity sensor. The onset of incipient sensor faults such as bias and scale factor faults in position and current sensor are detected and isolated using structured residuals that are generated using the UKF-A estimates. Bias and scale factor errors in the velocity sensor are detected using the statistical properties of the innovation sequence of the UKF-A. In the event of fault in the position sensor, real time reconfiguration using an estimate of the position from the UKF-A is used for continued operation of the system. Simulation results indicate that the isolation scheme formulated is capable of efficiently identifying incipient sensor faults and the reconfiguration scheme permits continued operation of the system in the presence of position sensor faults.
Analytical solution of a stiffened orthotropic plate using alternative displacement potential approach
Authors: Nath S K Deb , Ahmed S Reaz , Kim S-G
Published: September 2009

Analytical solution of elastic fields of a stiffened composite plate subjected to axial tension and pure bending is obtained using alternative displacement potential approach. In this approach, the problem is formulated in terms of a single potential function, defined in terms of the displacement components, which satisfies a single differential equation of equilibrium. All the parameters of the elastic field are expressed into algebraic equations using Fourier series. Assuming a trigonometric function as the displacement potential solution to the present problem, the mixed-boundary conditions at the stiffened edges are automatically satisfied. The resulting states of stress and displacement in the composite plate due to axial tension and pure bending are discussed in details. The effect of fibre orientation on the elastic field is also investigated.
Investigation on a streamtraced hypersonic Busemann inlet
Authors: Sun B , Zhang K-Y , Wang C-P , Wu X-S
Published: September 2009

Wind-tunnel testing and numerical simulation of a streamtraced hypersonic Busemann inlet were conducted at Mach 5.3 to investigate the flowfield characteristics and performance of this fixed-geometry inlet at conditions of design point. Wind-tunnel testing was also conducted at Mach 3.85 to investigate the starting and back-pressure limits of this inlet at conditions well below the design point. Results showed that the inlet could self-start at two tunnel conditions. At Mach 5.3, the inlet captured about 90 per cent of available air, generated a compression ratio of 29.9, and withstood a back-pressure ratio of 89 relative to tunnel static pressure; large separation of flow near the cowl closure resulted in flow at the exit of the inlet consisting of a majority of boundary layer by area. At Mach 3.85, the inlet generated a compression ratio of 11.92, captured about 83 per cent of available air, and withstood a back-pressure ratio of up to 34.3 relative to tunnel static pressure.
Algorithm and operational concept for resolving short-range conflicts
Authors: Erzberger H , Heere K
Published: September 2009

The article describes an algorithm for computing horizontal resolution trajectories with a limit on bank angle. If loss of separation can be avoided, the algorithm generates a set of manoeuvres that achieves or exceeds the specified minimum separation. The manoeuvres consist of turns to a specified heading followed by straight-line flight. Both single aircraft and cooperative manoeuvres are generated. In cooperative manoeuvres, both conflict aircraft simultaneously execute resolution manoeuvres, which expedite the resolution process compared to single aircraft manoeuvres. If loss of separation is unavoidable for a specified bank angle limit, the method chooses the manoeuvre that maximizes the minimum separation during the turns. The characteristics of the resolution trajectories have been analysed in a parameter space comprising initial positions, encounter angle, airspeed, predicted minimum separation, and bank angle. Analysis of resolutions for sets of initial conditions provided a road map for the design of an algorithm. The conceptual design of a system is described that resolves close-in conflicts automatically by uplinking resolution advisories to aircraft. Controllers have the option to assign detected conflicts to be resolved by the system. The system also has the authority to uplink resolution advisories to the aircraft without prior controller approval if time to loss of separation falls below a threshold value. The Mode S Specific Services data link is well suited for uplinking resolution advisories to the conflict aircraft. Deployment of the system could be an initial step in building the next-generation air traffic control system.
The opportunities and challenges associated with wireless interconnects in aircraft
Authors: Panitz M , Hope D C , Sato T , Harley C D , Christopoulos C , Sewell P , Dawson J F , Marvin A C , Fearon E , Watkins K G , Dearden G , Crowther W J
Published: September 2009

Utilizing wireless data buses in aircraft has the potential to increase reliability, reduce weight, and improve flexibility and adaptability. In this article, the implementation of wirelessly connected interconnects in aircraft is introduced from a broad perspective, considering the issues of radio systems, propagation, antennas, and applications.

Existing avionics systems are discussed briefly in order to understand the requirements placed on a wireless system and the specification it must meet. A review of existing wireless protocols and commercial off the shelf systems is provided, explaining where systems including ZigBee and IEEE 802.11 are suitable and unsuitable for a wireless aircraft application, and it is found that no existing system can be used exclusively. It is shown quantitatively that the propagation environment is expected to have high delay spreads and the negative impact of this on system reliability is shown through simulation and measurements.

The application and benefits of a direct write, in-situ, metallic deposition procedure are discussed for the placement of antennas, sensors, and their associated electronics. By writing electronics onto a surface, fitting and retrofitting are made much easier without the need to affect the aircraft structure, and this enables a more flexible wireless system. The opportunities, advantages and challenges for such a technology within the wireless aircraft are discussed.
Application of circulation control for three-axis control of a tailless flight vehicle
Authors: Wilde P I A , Crowther W J , Harley C D
Published: September 2009

The application of circulation control (CC) manoeuvre effectors to a tailless flight vehicle enables the possibility of providing control moments about three axes without the use of conventional control surfaces. Strong similarities exist between the use of split flap elevons and CC units used as trailing edge devices for the provision of three-axis control. Both control types can produce independent roll and pitching moments by lateral symmetric operation. Yawing moments can also be produced by simultaneous blowing from upper and lower CC slots increasing the local section axial force. An existing datasheet method for predicting the lift and pitching moment increments for plain flaps is modified to support some aspects of sizing CC devices; however, there are some significant gaps such as high fidelity models for the prediction of Coanda jet separation from the curved trailing edge, which require further research. A case study is presented in which the provision of three-axis control moments using CC is evaluated for a tailless 20 kg class gas-turbine-powered model aircraft. Wind tunnel experiments are used to demonstrate the validity of the aerodynamic design of the vehicle and the ability to produce control moments from CC sufficient to meet basic trim and manoeuvre requirements. The peak values of CC control gains achieved for δ CL/ δ Cμ is 20 and the control gain for δ CD/ δ Cμ for use as part of a ‘thrust’-based yaw control scheme from blowing from both upper and lower slots is low (∼0.5); however this is sufficient to trim the case study aircraft at 8° of sideslip at cruise conditions with 10 per cent mass flow bleed from the engine. For lateral symmetric operation of CC controls, the change in pitching moment with control lift increment has been shown to be similar for both CC and flaperon devices
Replacement of industrial testing composite structures by simulation
Authors: Davies G A O , Ankersen J , Guiamatsia I , Gordon B
Published: September 2009

This article summarizes the work undertaken during the period 2007–2008 by the Materials and Structures task within FLAVIIR. The aim was to examine how much structural testing could be realistically replaced by simulation. The aim was to employ a finite-element (FE) code that could be used as a design tool by non-experts in FE technology. The non-linear software code used is ABAQUS and it was found that the complex features, in tests of many composite structures to failure, were simulated well and agreed with the experimental tests. Examples quoted are a ‘T’ stiffener bonded to a skin, and a joint bolting a composite skin to a metallic substructure. One of the problems to be overcome is the apparent need for tiny FEs representing the interfaces at an opening crack/debond/delamination. Solutions are suggested.
Analysis of size distribution and ignition temperature effects on flame speeds in aluminium dust clouds
Authors: Bidabadi M , Moallemi N , Shabani A , Abdous M A
Published: September 2009

Reaction rate plays a major role in modelling of aluminium dust cloud combustion. In this article, a new model for the reaction rate is presented as a function of aluminium particle size distributions and ignition temperature of each particle. Moreover, the reaction rate is obtained in proportion to the amount of fuel considered to be constant in the reaction zone of previous models. In comparison with the old models, the new model is closer to the experimental results.
A hybrid finite element—finite volume method for incompressible flow through complex geometries using mixed grids
Authors: Lal S Anil , Jabir E
Published: September 2009

A simple, robust, local divergence free, second-order accurate, stable solution procedure for incompressible flows using a finite element method for the evaluation of velocity components and a finite volume method for the evaluation of pressure is presented. In order to ensure pressure stability, the velocity components (at vertices) and pressure (at cell centres) are evaluated at different points of the elements. The finite element—finite volume combinations are taken from triangular and quadrilateral grids. These grids are used alone or together as mixed grids. A new element-cell configuration consisting of two adjacent triangular elements together as a finite volume quadrilateral cell for the evaluation of pressure is introduced. Predictions are found to be in good agreement with the available results for all types of grids used. The present method combines the pressure stability of the staggered grid finite volume method (FVM) and the flexibility of the finite element approach to analyse flow through complex geometries; it is easy to implement and locally divergence free.
An all-composite, all-electric, morphing trailing edge device for flight control on a blended-wing-body airliner
Authors: Wildschek A , Havar T , Plötner K
Published: September 2009

For a significant improvement in the fuel efficiency of long-range transport aircraft, a transition to blended-wing-body (BWB) configurations will be required in the long term. Further efficiency improvements are expected from an all-composite primary structure, all-electric actuation, as well as from seamless control surfaces that provide reduced drag compared to conventional control surfaces. BWB configurations feature specific demands on the control system because of the high coupling between flap deflections and aircraft movements in all three axes. Thus, multi-objective control surfaces are required for flight control, as well as for active gust and manoeuvre load alleviation. A major challenge therefore is to provide sufficient yaw control and stability in the absence of a vertical tail. Generally, one engine inoperative poses an important sizing case for the control system design, especially for the control surfaces. In this article, the sizing of winglet flaps and crocodile flaps is performed for the preliminary design of an all-composite, all-electric BWB airliner. For further improvement in efficiency, a seamless morphing trailing edge device is designed that provides both crocodile flap and aileron modes at the same time. Based on these results, a composite morphing trailing edge demonstrator with an all-electric actuation system is investigated. Some open issues remain for investigation. Still, the proposed design provides a promising approach for further efficiency improvement on BWB aircraft configurations.
An experimental study of resistant properties of the small intestine for an active capsule endoscope
Authors: Wang X , Meng M Q-H
Published: September 2009

Use of the capsule endoscope (CE) in clinical examinations is limited by its passive movement resulting from the natural peristalsis of the gastrointestinal (GI) tract. Therefore, a locomotion mechanism is desirable for the next generation of capsule endoscope. Understanding the resistant properties of the small intestine is essential for designing a wireless magnetic actuation mechanism. In this paper, in vitro experiments were carried out to investigate the resistant force of the small intestine using 15 specially designed capsule prototypes and analysed the effect of the capsule dimension and moving speed. Segments of porcine small intestine were employed as a conservative model for the human intestine. When the capsules under experiment were moving at a speed of 0.5 mm/s, a resistant force of 20 to 100 mN were measured for the capsule diameter in the range of 8 to 13 mm. The force increased with moving speed. The intrinsic cause of the resistant force of the small intestine is discussed based on an analysis of the experimental data. It is believed that the viscoelastic properties of the tissue play an important role in the resistant characteristics of the small intestine.