Low Load Conditions Research Articles

The effect of working memory load on inattentional deafness during aeronautical decision-making

Operating an aircraft requires pilots to handle a significant amount of multi-modal information, which creates a high working memory load. Detecting auditory alarms in this high-load scenario is crucial for aviation safety. According to cognitive control load theory, an increase in working memory load may enhance distractor interference, resulting in improved detection sensitivity for task-irrelevant stimuli. Therefore, understanding the effect of working memory load on auditory alarm detection is of particular interest in aviation safety research. The studies were designed to investigate the effect of storage load and executive function load of working memory on auditory alarm detection during aeronautical decision-making through three experiments. In Experiment 1 and 2, participants performed an aeronautical decision-making task while also detecting an auditory alarm during the retention interval of a working memory task (visual-spatial, visual-verbal and auditory-verbal). In Experiment 3, participants were required to detect an auditory alarm while performing the 2-back and 3-back aeronautical decision-making tasks. Experiment 1 found that the auditory alarm sensitivity was higher in conditions of low visual-spatial working memory storage load compare to high load conditions. Experiment 2 found that a high storage load of visual-verbal working memory reduced auditory alarm sensitivity but auditory-verbal working memory load did not. Experiment 3 found that, unlike storage load, auditory alarm sensitivity was stronger under high executive function load relative to low executive function load. These findings show that working memory storage load and executive function load have different effects on auditory alarm sensitivity. The relationship between executive function and auditory alarm sensitivity supports cognitive control load theory, while the impact of the storage function on auditory alarm sensitivity does not adhere to this theory.

The Role of Explicit Memory Across Second Language Syntactic Development: A Structural Priming Study

AbstractWe tested whether second language (L2) learners rely more on explicit memory during structural priming at lower than at higher proficiency levels (Hartsuiker & Bernolet, 2017). We compared within‐L2 priming with lexical overlap in 100 low and 100 high proficiency French L2 speakers under low versus high working memory load conditions induced with a letter series recall task presented between primes and targets. The high load condition would prevent explicit recall of primes during target production. Both groups primed more under low than high load. The effect of load was similar across groups, but exploratory analyses with proficiency as a continuous variable suggested that, with increasing proficiency, participants primed less under high load. We discuss how these findings support the idea that learners exploit explicit memory more during priming in early versus later stages of acquisition. Overall, this study showed that explicit memory influences syntactic processing across the L2 learning trajectory.

Analysis of the fractal characteristics for combustion instability in a premixed natural gas engine

To investigate the influence of gas injection timing (GIT) on the combustion instability of a premixed natural gas engine, experiments were conducted under low load conditions using various GITs. Multifractal and multiscale entropy analyses were employed to examine the fractal characteristics and complexity of the experimental time series for indicated mean effective pressure (IMEP) and heat release (Q) at different scales. Statistical analysis and return maps of the IMEP and Q time series were utilized to verify the results. The findings revealed that the combustion process of the natural gas engine demonstrates clear fractal characteristics at different scales. A strong correlation is found between the combustion instability and the fractal characteristics. Furthermore, the probability densities of the IMEP and Q time series exhibit super-Gaussian distributions. Retarding the GIT results in an initial increase, followed by a decrease in the difference value of the Hurst index and singular spectrum width. The mapping point distributions of the IMEP and Q time series initially disperse and subsequently concentrate. The fractal complexity and chaotic characteristics of combustion instability initially strengthen and then gradually diminish. Moreover, under lower load conditions, the anti-persistent correlation becomes more pronounced, and the intermittence and complexity of the fractal characteristics also intensify, signifying a more significant impact of GIT on the combustion instability of the natural gas engine. Notably, when the GIT is approximately 60°CA after top dead center, the combustion process exhibits stronger fractal characteristics, accompanied by a greater dispersion degree of the mapping points. This study provides a theoretical basis for enhancing the lean-burn stability of natural gas engines.

Optimization of end-wall fence in turbine based on response surface methodology and genetic algorithm

Secondary flow loss accounts for a large proportion of the internal flow loss in turbine stages. The use of end-wall fences can effectively reduce secondary flow loss. In this study, the White cascade was taken as the research object, and the position of the end-wall fence was parameterized. Based on the response surface method, the mapping relationship between the fence position and the isentropic expansion efficiency was obtained, and a surrogate model was constructed. Finally, single-objective and multiobjective optimizations were carried out using genetic algorithms to obtain the optimal fence position parameters. The results showed that the existence of the fence can not only reduce secondary flow but also effectively reduce shock losses when the fence is located at the rear of the passage. Therefore, the optimization effect of the blade position is best when it is located at the end of the passage. When the flow deviates significantly from the design condition, the end-wall fence can significantly reduce the low-speed region on the pressure side of the fence. Therefore, the fence can play a greater role in low-load conditions with significant deviations from the design condition. After optimizing the design conditions, when H is 128.6 mm, V is 66.93 mm, and A is 56.48°, the isentropic expansion efficiency is the highest, reaching 96.160%. After optimizing the multi-inlet angle at low load conditions, when θ is 56.07°, R is 129.7 mm, and A is 64.36°, the comprehensive optimization result is the best, and the isentropic expansion efficiencies at inlet angles of 0°, 10°, and 45° are 96.098%, 96.050%, and 93.930%, respectively. The research results can provide a reference for the design of turbine flow.

The benefits of mind wandering on a naturalistic prospective memory task

Mind wandering (MW) occurs when our attention spontaneously shifts from the task at hand to inner thoughts. MW is often future-oriented and may help people remember to carry out their planned actions (Prospective Memory, PM). Past-oriented MW might also play a critical role in boosting PM performance. Sixty participants learned 24 PM items and recalled them during an immersive virtual walk in a town. The items were divided into event-based—EB and time-based—TB. During the PM retention phase, participants were randomly assigned to a high or a low cognitive load condition, in order to manipulate MW frequency. Some PM items were encoded before this MW manipulation (pre-PM) and some during the virtual walk (post-PM). A high MW frequency was linked with better global PM performances. Spontaneous past-oriented MW predicted better pre-EB retrospective PM retrieval, while spontaneous future-oriented MW predicted better Pre-EB prospective PM retrieval. Voluntary future-oriented MW predicted better post-EB retrospective retrieval. We highlighted, for the first time, a differential impact of spontaneous MW content depending on the PM component (retrospective or prospective). Past‐oriented MW is crucial for (re)consolidating PM intentions, and episodic future thinking MW for the execution of PM intentions. We discuss the twofold functional role of MW, namely, to consolidate an already programmed intention and to plan future actions.

Application and Efficiency of a Series-Hybrid Drive for Agricultural Use Based on a Modified Version of the World Harmonized Transient Cycle

Off-road vehicles and transportation are vital for agricultural economics, yet the transition to green energies is challenging. To make this transition easier, a tool that enables the testing of heavy-duty off-road vehicles in various scenarios was created. Based on the methods of the World Harmonized Transient Cycle (WHTC), a new Hybrid Operational Cycle (HOC) that reflects the features of agricultural work was created and applied in a graphical model simulation. This was a newly developed methodology. The cycle and the model were based on gathered research data. A numerical model of a medium-power tractor with an internal combustion engine and a series-hybrid setup was created, and simulations were performed in Matlab and AVL Cruise. Both diesel and hybrid vehicles were compared in terms of their power production, fuel consumption, and efficiency in fieldwork and transportation scenarios. The results showed that a series-hybrid transmission can achieve an efficiency similar to that of a tractor with a continuously variable transmission (CVT), but because it uses an electric powertrain, it still provides the opportunity to exploit energy regeneration during transportation and under low-load conditions. The designed model may also be used to develop control algorithms for hybrid drives and improve their efficiency.

ConnSearch: A framework for functional connectivity analysis designed for interpretability and effectiveness at limited sample sizes

Functional connectivity studies increasingly turn to machine learning methods, which typically involve fitting a connectome-wide classifier, then conducting post hoc interpretation analyses to identify the neural correlates that best predict a dependent variable. However, this traditional analytic paradigm suffers from two main limitations. First, even if classifiers are perfectly accurate, interpretation analyses may not identify all the patterns expressed by a dependent variable. Second, even if classifiers are generalizable, the patterns implicated via interpretation analyses may not replicate. In other words, this traditional approach can yield effective classifiers while falling short of most neuroscientists’ goals: pinpointing the neural correlates of dependent variables. We propose a new framework for multivariate analysis, ConnSearch, which involves dividing the connectome into components (e.g., groups of highly connected regions) and fitting an independent model for each component (e.g., a support vector machine or a correlation-based model). Conclusions about the link between a dependent variable and the brain are based on which components yield predictive models rather than on interpretation analysis. We used working memory data from the Human Connectome Project (N = 50–250) to compare ConnSearch with four existing connectome-wide classification/interpretation methods. For each approach, the models attempted to classify examples as being from the high-load or low-load conditions (binary labels). Relative to traditional methods, ConnSearch identified neural correlates that were more comprehensive, had greater consistency with the WM literature, and better replicated across datasets. Hence, ConnSearch is well-positioned to be an effective tool for functional connectivity research.

Effect of PVA fibres and crystalline admixtures on the self-healing efficiency under long-term aconstant loading

Cracks in cement-based materials affect the strength and durability. This study explored the synergistic effect of polyvinyl alcohol (PVA) fibres and crystalline admixtures on the self-healing properties under long-term constant loading conditions. First, specimens with varying degrees of pre-damage were obtained. The pre-damaged specimens were then cured with and without constant applied load. The self-healing efficiency was evaluated based on the compressive strength, and the self-healing mechanism was analysed based on the changes in porosity. When curing was performed without a load, the compressive strength increased to different extents. Conversely, when cured under constant loading conditions, the compressive strength increased under low-load conditions, and the compressive strength decreased under high-load conditions. The porosity exhibited a similar pattern of variation. The self-healing efficiency was found to be dependent on both the damage caused by long-term constant loading and the repairing effects achieved during the curing process. When subjected to external forces, PVA fibres inhibited crack propagation, and crystalline admixtures repaired the cracks after they appeared. This demonstrates the successful integration of “control-repair” in cracks. The curing conditions involving long-term constant loading better simulated real engineering scenarios, which distinguishes this work from those performed under no-load curing conditions. This study represents a valuable exploration of self-healing technology.

Anisotropy of the Tribological Performance of Periodically Oxidated Laser-Induced Periodic Surface Structures

Laser-induced periodic surface structures (LIPSS) enable advanced surface functionalization with broad applications in various fields such as micro- and nanoelectronics, medicine, microbiology, tribology, anti-icing systems, and more. This study demonstrates the possibility of achieving anisotropy in the tribological behavior of C45-grade steel structured by nanosecond laser radiation using the LIPSS method. The lateral surface of the steel roller was irradiated with a pulsed Nd:YAG laser at an optimum intensity I = 870 MW/cm2 for the formation of LIPSS. Two sets of samples were formed with LIPSS that were perpendicular and parallel to the roller’s rotational motion direction. The Raman intensity maps revealed that the LIPSS structure consisted of periodically arranged oxides at the top of hills. At the same time, the valleys of the LIPSS structures were almost not oxidized. These results correlated well with scanning electron microscopy energy dispersive X-ray spectroscopy mapping and atomic force microscopy measurements. A comparison of Raman and X-ray photoelectron spectroscopy spectra revealed that both the magnetite phase and traces of the hematite phase were present on the surface of the samples. Tribological tests were performed in two cycles with periodic changes in the normal clamping force and sliding speed. It was found that the LIPSS structures which were formed perpendicularly to the sliding direction on the roller had a significantly greater impact on the friction processes. Structures oriented perpendicular to the direction of motion had a positive influence on reducing the energy consumption of a friction process as well as increasing the wear resistance compared to LIPSS formed parallel to the direction of motion or ones having a non-texturized surface. Laser texturing to produce LIPSS perpendicular to the direction of motion could be recommended for friction pairs operating under low-load conditions.

Influence of injection strategies on ignition patterns of RCCI combustion engine fuelled with hydrogen enriched natural gas

The depletion of fossil fuel and the concerns for harmful emissions and global warming has instigated researchers to use alternative fuels. Hydrogen (H2) and natural gas (NG) are attractive fuels for internal combustion engines. The dual-fuel combustion strategy is promising to reduce emissions with efficient engine operation. The concern for using NG in this strategy is the lower efficiency at low load conditions and the emission of exhaust gases like carbon monoxide and unburnt hydrocarbon. Mixing fuel with a wide flammability limit and a faster burning rate with NG is an effective method to compensate for the limitations of using NG alone. Hydrogen (H2) is the best fuel added with NG to cover NG limitations. This study investigates the in-cylinder combustion phenomenon of reactivity-controlled compression ignition (RCCI) engines using hydrogen-added NG as a low-reactive fuel (H2 addition to NG on a 5% energy basis) and diesel as a highly reactive fuel. The numerical study was done on a 2.44 L heavy-duty engine using CONVERGE CFD code. Three low, mid, and high load conditions were analyzed in six stages by varying the diesel injection timing from −11 to −21 O after top dead centre (ATDC). The H2 addition to NG had shown deficient harmful emissions generation like carbon monoxide (CO) and unburnt hydrocarbon with marginal NOx generation. At low load conditions, the maximum imep was achieved at the advanced injection timing of −21OATDC, but with the increase in load, the optimum timing was retarded. The diesel injection timing varied the optimum performance of the engine for these three load conditions.

Harmonic Injection Strategy Considering Multiplane Iron Loss Impact With Optimal Magnetizing Flux Distribution for Multiphase Induction Machines

Lagging orientation error detuning induced by iron losses for multi-planes of multiphase IM under non-sinusoidal supply control triggers error in determination of calculated harmonic, fundamental air-gap flux advance angles and harmonic slip frequency. This in-turn leads to inaccurate harmonic injected currents, which are dependent on harmonic multiple of frequency for the corresponding plane with respect to fundamental plane frequency. This paper proposes the novel harmonic injection strategy considering the detuned impact of iron losses by keeping in view the complete iron loss modeling for both harmonic magnetizing flux orientation control (MFOC) and fundamental rotor flux orientation control (RFOC) planes. Furthermore, satisfaction of complete optimal flux distribution constraints for multiphase IM are taken into account which results in preserving optimal flux patterns throughout the mechanical loading particularly at low and medium load conditions. Contrary to other traditional orientation schemes, this paper adopts the MFOC and RFOC for harmonic and fundamental plane respectively for acquiring the aligned and synchronized control of harmonic and fundamental air-gap flux distribution. Detailed experimental results incorporating seven phase induction machine as prototype are utilized to evaluate the harmonic injected currents, advance angles, slip frequencies and induced EMF waveforms which validate the effectiveness of proposed scheme.

Effects of injection pressure and timing on low load low temperature gasoline combustion using LES

Low Temperature Gasoline Combustion is a novel combustion strategy that employs the use of a fuel like gasoline whose autoignition characteristics are sensitive to varying concentrations of fuel. It has the potential to dramatically reduce nitrogen oxide (NOx) and soot emissions relative to conventional combustion modes with similar thermal efficiency and has the added production benefit of using a widely available fuel. To address efficiency at low loads, a single direct injection (S-DI) is used that stratifies the fuel enough to get sufficient combustion performance. But with the increased fuel stratification, there is the potential to create undesirable fuel distributions that could increase harmful NOx emissions. This work uses three-dimensional computational fluid dynamics (3D-CFD) to investigate the effects of injection parameters including injection pressure, start of injection timing, and intake valve closing temperature on this S-DI strategy using a medium-duty engine at two low load conditions. A computational model was developed and validated to experimental data collected on this engine using Large Eddy Simulations turbulence modeling to resolve the complex flow phenomena and turbulent mixing prevalent in this combustion strategy.Injection pressure was increased in six increments from 120 bar to 342 bar at constant start of injection (SOI) of 45 crank angle degrees before top dead center and the effects on performance and emissions are analyzed at two load operating conditions of 2 and 3 bar. Then, at each injection pressure, the start of injection timing was delayed to analyze its impact on combustion performance. The tradeoffs for performance and emissions with these injection parameters are explored along with suggestions for further investigations to improve this S-DI injection process.

МОДЕЛИРОВАНИЕ ИСХОДНОЙ ЗАСОРЕННОСТИ ЗЕРНОСМЕСИ ПО ВЕЛИЧИНЕ ЗАГРУЗКИ ТРИЕРА И ПАРАМЕТРАМ РАСПРЕДЕЛИТЕЛЬНЫХ КОРОБОВ

Investigation of the dosing quality of the impurity component at low loading conditions of the experimental trier and low initial clogging with a long impurity using three distribution boxes with dimensions: 600 × 14 × 13 mm; 600×24×13 mm; 600×24×21 mm are made. Dosing quality indicators - the standard deviation and the coefficient of variation for single, pair, triple, quadruple and five distributing boxes, characterizing the required linear density of the distribution of the impurity component on the feeder belt, have been established. It has been established that the use of these boxes provides high dosing stability. The coefficient of variation under different conditions of their loading does not exceed 4.75%. Filling boxes with dimensions of 600×14×13 mm with shaking of impurities provides a higher quality of dosing: the standard deviation is lower by 18.9 - 47.32%, the coefficient of variation is by 23.96 - 49.45% for different frequency of unloading boxes at formation of the linear density of the impurity layer on the tape. A number of model compositions of grain mixtures, providing for the supply of 1.2 t / h, the variability of the initial contamination in the range of 0.46 - 6.65%; for the supply of 1.83 t/h, the range of initial contamination is 0.3 - 4.3%; for the supply of 2.45 t/h, the range of initial contamination is 0.22 - 3.25%; for the supply of 3.07 t/h, the range of initial contamination is 0.18 - 2.6%; for the supply of 3.71 t/h, the range of initial contamination is 0.15 - 2.15%; for the supply of 4.35 t/h, the range of initial contamination is 0.125 - 1.8%. established on the basis of the performed calculations. Distribution boxes of small cross section provide 20 interval values with a minimum step for each range of initial contamination, which allows you to qualitatively control the experiment when using a grain mixture with low values of contamination of the grain mixture and productivity of the trier.

Instructional load induces functional connectivity changes linked to task automaticity and mnemonic preference

Learning new rules rapidly and effectively via instructions is ubiquitous in our daily lives, yet the underlying cognitive and neural mechanisms are complex. Using functional magnetic resonance imaging we examined the effects of different instructional load conditions (4 vs. 10 stimulus-response rules) on functional couplings during rule implementation (always 4 rules). Focusing on connections of lateral prefrontal cortex (LPFC) regions, the results emphasized an opposing trend of load-related changes in LPFC-seeded couplings. On the one hand, during the low-load condition LPFC regions were more strongly coupled with cortical areas mostly assigned to networks such as the fronto-parietal network and the dorsal attention network. On the other hand, during the high-load condition, the same LPFC areas were more strongly coupled with default mode network areas. These results suggest differences in automated processing evoked by features of the instruction and an enduring response conflict mediated by lingering episodic long-term memory traces when instructional load exceeds working memory capacity limits. The ventrolateral prefrontal cortex (VLPFC) exhibited hemispherical differences regarding whole-brain coupling and practice-related dynamics. Left VLPFC connections showed a persistent load-related effect independent of practice and were associated with ‘objective’ learning success in overt behavioral performance, consistent with a role in mediating the enduring influence of the initially instructed task rules. Right VLPFC's connections, in turn, were more susceptible to practice-related effects, suggesting a more flexible role possibly related to ongoing rule updating processes throughout rule implementation.

A quantitative study on the combustion and emission characteristics of an Ammonia-Diesel Dual-fuel (ADDF) engine

In order to resolve the global warming problem, Ammonia-Diesel Dual-Fuel (ADDF) combustion has been a feasible strategy for burning ammonia to reduce carbon emissions from internal combustion engines. In the research of this paper, an ADDF engine experimental platform was developed and established. Premixed-Charge Compression Ignition (PCCI) combustion and diesel-piloted combustion modes under different operating conditions were investigated to achieve the goals of high thermal efficiency and low emissions. Moreover, the influence of diesel injection strategy and intake pressure on combustion, gaseous and particle emissions were explored. The results indicate that high thermal efficiency can be obtained using PCCI mode with early injected diesel, which forms a homogeneous mixture with ammonia under the low load condition. Under medium and high load conditions, less diesel was injected early, and ignition was delivered by a pilot injection of diesel close to the top dead centre. Under all operating conditions, the gross indicated thermal efficiency (ITEg) exceeded 48%, and the maximum ITEg was 51.5%, which was comparable to the diesel-only mode. Meantime, the emission of ammonia, NO and N2O were normally below 6 g/kWh, 7 g/kWh, and 1 g/kWh, respectively. With increasing ammonia energy substitution ratio, the particle emission changed from accumulation-mode particles to nucleation-mode particles, but the mass of accumulation-mode particles dominated.

Novel approach for efficient operation and reduced harmful emissions on a dual-fuel research engine propelled with hydrogen-enriched natural gas and diesel

ABSTRACT The stricter emission norms have created a need to study recent combustion technology in internal combustion engines. Dual-fuel (DF) combustion technology is one of the key techniques to achieve future emission goals. Natural gas is one of the easily available low-reactive fuels worldwide that can be used in the DF combustion strategy. The main problem with using NG in the DF strategy is its lean-burning ability to produce emissions like HC and CO. The combustion losses associated due to crevice losses in the piston geometry are also the reasons for getting degraded engine performance. In the present study, the lean flammability of NG was improved by enriching it with hydrogen. The combustion losses were reduced using modified disc piston geometry with lower crevice volume. The results showed that the thermal efficiency obtained using HENG/diesel DF strategy with disc piston (DF disc) was only less than 0.3%, 0.4%, and 1% for low, mid, and high load conditions compared to conventional compression ignition mode using bowl piston (CI bowl). The change in piston geometry from bowl to disc type using the DF strategy improved the thermal efficiency by about 3.8%, 3.3%, and 2.7% for three load conditions. The NOx and smoke opacity reduction by about 6% to 19% and 40% to 60% in DF disc mode was achieved compared to CI bowl mode.

Combustion characteristics and misfire mechanism of a passive pre-chamber direct-injection gasoline engine

Engine combustion characteristics and misfire phenomena in a turbocharged direct-injection gasoline engine with a pre-chamber are studied through multi-dimensional modeling of the engine and jet combustion in a pre-chamber vessel. The results show that the high-speed jets generated by the pre-chamber after spark ignition result in multiple ignition spots and enhanced flow turbulence in the main combustion chamber, accelerating the subsequent turbulent flame propagation. It is also found that the momentum of the gas jets directly correlates with the main chamber combustion phasing and duration, which means that varying the design parameters of the pre-chamber to generate higher jet momentum can produce faster flame propagation and better combustion phasing, improving the engine’s thermal efficiency. On the other hand, flame quenching phenomena at the engine low-load conditions were captured in the simulation with the reaction-mechanism combustion model, whose predictivity of jet flame quenching was verified by the pre-chamber vessel experiments. It was found that, in addition to the unfavorable lower in-cylinder pressure and temperature, leaner fuel–air mixture, weaker turbulence, and wall heat losses would lead to slower flame development in the pre-chamber and the jet flame to quench in the main chamber, resulting in engine misfire or ignition instability. The simulation further verified that flame quenching could be mitigated by using a heat-insulated pre-chamber, improving air–fuel mixing in the main chamber and pre-chamber with advanced fuel injection timing, and igniting the mixture at a higher gas temperature and pressure with advanced spark timing.

Influence of fuel injection parameters at low-load conditions in a partially premixed combustion (PPC) based heavy-duty optical engine

The study examined the effects of second injection timings and fuel injection pressures (FIPs) in a double-injection based partially premixed combustion (PPC) using a single-cylinder heavy-duty optical diesel engine equipped with two different configurations, namely all-metal and optical. The thermodynamic analysis of energy balance, exhaust emissions, and particulates characterization was conducted in an all-metal engine configuration. For the same base engine architecture, high-speed natural combustion luminosity, cool-flame, and electronically excited hydroxyl (OH*) chemiluminescence, and planar laser-induced fluorescence (PLIF) imaging of formaldehyde (HCHO-PLIF) were applied in the optical configuration. Additionally, 1D modeling using GT-Power was utilized to examine the distribution of heat transfer losses through the individual cylinder boundaries. The experiments were conducted at low-load conditions at a fixed fuel mean effective pressure (MEPfuel) using a primary reference fuel with a volumetric mixture of 50% n-heptane and 50% iso-octane (PRF50). The results demonstrated that for a fixed first injection, the second injection timing of −6°CA aTDC is the most favorable condition due to increased gross indicated efficiency, reduced exhaust losses, decreased uHC/CO/soot emissions with a slight compromise on heat losses and NOx emissions. Among the tested FIPs of 1200, 1500, and 1800 bar, 1500 bar showed higher efficiency, and overall lower energy losses and exhaust emissions. At higher FIPs, the overall flame development process revealed reduced luminous intensity with dispersed signals formed downstream of the nozzle due to increased premixed combustion. For 1800 bar FIP, both cool-flame and HCHO signals showed an increased rate of reaction zones close to the bowl-wall region from where the OH radicals developed. Not only the initial low- to high-temperature reaction transition was faster for 1800 bar FIP but the signal decay of HCHO signals by OH radicals was also rapid in the late cycle. These findings explained the root cause of increased heat transfer losses and higher uHC/CO emissions at 1800 bar FIP.

High temperature VHCF of a 3rd generation Ni-based single crystal superalloy with different casting pore sizes

Very high cycle fatigue (VHCF) of a Ni-based single crystal superalloy processed by high-rate solidification (HRS), liquid metal cooling (LMC) and HRS plus hot isostatic pressing (HIP), respectively were studied at 1000 °C, 20 kHz and R = -1. For HRS and LMC, the fatal cracks mainly initiate from casting pores surrounded by a rough zone. γ′-rotation as the main feature within the rough zone is related to the operation of {111}〈110〉 and {111}〈112〉 slip systems. HRS+HIP specimens mainly fail from the surface and they present the best VHCF property. LMC process could increase the VHCF durability like HIP treatment, especially at very low loading conditions.

Prospective memory: the combined impact of cognitive load and task focality

Prospective Memory (PM) entails a set of executive processes primarily associated with the activation of frontal and parietal regions. Both the number of PM-targets to be monitored (i.e. task load) and the relationship between the type of PM-targets and the ongoing (ONG) task (i.e. task focality) can impact executive monitoring and PM performance. In the present imaging study, we manipulated load and focality of an event-based PM task to test the hypothesis that common resources engage in situations requiring high levels of cognitive control: that is, in high-load (i.e. monitor multiple PM-targets) and non-focal conditions (i.e. monitor at the same time letters’ identity and color). We investigated monitoring-related and detection-related processes by assessing behavior and brain activity separately for ONG trials (monitoring) and PM-targets (detection). At the behavioral level, we found a significant interaction between load and focality during detection, with slowest reaction times for focal, high-load PM-targets. The imaging analyses of the detection phase revealed the activation of the left intraparietal sulcus in the high-load conditions. Both in the monitoring and the detection phases, we found overlapping effects of non-focality and low-load in the fusiform gyrus. Our results suggest that under low-load conditions, cognitive control operates via early selection mechanisms in the ventral occipito-temporal cortex. By contrast, high-load conditions entail control at later processing stages within the dorsal parietal cortex. We conclude that load and focality operate via different mechanisms, with the level of task load largely determining how cognitive control selects the most relevant information.