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This study presents a novel manufacturing method of large-scale, soft magnetic FeSi samples (Si 3.5 wt%) with enhanced magnetic properties, devoid of defects, through the application of direct energy deposition (DED). The effects of different manufacturing process parameters on grain morphology (i.e., size, direction, texture) were systematically investigated. A large volume ratio (68.3%) of Goss texture ({110} < 001 >) was formed at the as-printed stage with the grain direction of ~ 33° toward the building direction. The volume ratio of Goss texture was increased to 82.7% after post-heat treatment at 1050 °C for 2 h. The maximum relative permeability of 10710 was achieved after post-heat treatment at 1050 °C for 2 h, which is comparable to commercially available FeSi steel made by the traditional manufacturing method. The magnetic performance results indicate potential improvement of magnetic properties with further optimized grain structure and elevated post-heat treatment temperature. DED-printed FeSi showed higher microhardness and yield strength (284 HV and 625 MPa) compared to FeSi from conventional manufacturing methods. [ABSTRACT FROM AUTHOR]

In general, a leaner mixture condition improves combustion efficiency in compression ignition (CI) combustion using diesel. However, in the case of leaner air–fuel mixture conditions, it disturbs flame propagation in spark ignition combustion using gasoline, i.e., low reactivity fuel, causing a decrease in combustion efficiency. Since dual-fuel combustion in a CI engine typically involves the use of high- and low-reactivity fuels together, the differing reactivity conditions in the cylinder become as important as the local equivalence ratio in the cylinder. Thus, there is a need to verify the effect of a leaner mixture condition on combustion efficiency in dual-fuel CI combustion. For this reason, this study experimentally evaluates the effects of varying equivalence ratios on the combustion efficiency of gasoline/diesel dual-fueled CI combustion in a 0.4-L single-cylinder engine under low-speed (1500 rpm) and low-load (total LHV 570 J/str) conditions. To vary the equivalence ratios, intake pressures and exhaust gas recirculation (EGR) rates were, respectively, changed under the part-load condition. The results emphasize that as the equivalence ratio becomes leaner by increasing the intake pressure, combustion efficiency worsens due to the low reactivity properties and certain flame propagation modes of gasoline combustion. On the contrary, increasing the EGR rate did not significantly influence combustion efficiency, but it effectively helped reduce nitrogen oxide (NOx) emissions. Based on these results, it is concluded that optimizing dual-fuel CI combustion to suppress NOx emissions is better achieved using EGR, rather than creating a leaner mixture condition. [ABSTRACT FROM AUTHOR]

In this experiment, it was experimentally investigated the combustion and exhaust characteristics, as well as the thermal efficiency, of RCCI combustion using gasoline, ethanol, and propane as low-reactivity fuels under four operating conditions. For each operating condition, gISNOx was limited to 0.15 g/kWh, and gISSmoke was limited to below 15 mg/kWh. The experiment was conducted by determining the operating conditions that satisfied these limitations and resulted in the highest city thermal efficiency. The low-reactivity fuels were supplied by port injection, while diesel was directly injected into the combustion chamber using a diesel injector. As a result, when gasoline is replaced with low-carbon fuels like ethanol and propane, the reduction in CO2 emissions occurred. Under maximum power conditions, using ethanol allowed for a maximum reduction in CO2 emissions of 6.81%. Depending on the driving conditions, ethanol showed a reduction ranging from 3.60 to 6.81%, while propane exhibited a reduction ranging from 3.10 to 5.64%. Additionally, by substituting with ethanol and propane, the GIE could be improved up to 44.73 and 43.56%, respectively. [ABSTRACT FROM AUTHOR]

Spicules, the smallest observable jetlike dynamic features ubiquitous in the chromosphere, are supposedly an important potential source for small-scale solar wind transients, with supporting evidence yet needed. We studied the high-resolution H α images (0.″10) and magnetograms (0.″29) from the Big Bear Solar Observatory to find that spicules are an ideal candidate for the solar wind magnetic switchbacks detected by the Parker Solar Probe (PSP). It is not that spicules are a miniature of coronal jets, but that they have unique properties not found in other solar candidates in explaining solar origin of switchbacks. (1) The spicules under this study originate from filigrees, all in a single magnetic polarity. Since filigrees are known as footpoints of open fields, the spicule guiding field lines can form a unipolar funnel, which is needed to create an SB patch, a group of field lines that switch from one common base polarity to the other polarity. (2) The spicules come in a cluster lined up along a supergranulation boundary, and the simulated waiting times from their spatial intervals exhibit a number distribution continuously decreasing from a few seconds to ∼30 minutes, similar to that of switchbacks. (3) From a time–distance map for spicules, we estimate their occurrence rate as 0.55 spicules Mm−2 s−1, which is sufficiently high for detection by PSP. In addition, the dissimilarity of spicules with coronal jets, including the absence of base brightening and low correlation with EUV emission, is briefly discussed. [ABSTRACT FROM AUTHOR]

Ammonia is gaining attention as a non-carbon environmental-friendly fuel due to its superior storage capability compared to hydrogen. However, its high minimum ignition energy and slow laminar flame speed make it unsuitable for application in combustion-based energy conversion devices. In particular, when applied to internal combustion engines, issues such as combustion instability and limitations in operational range exist. Therefore, the intention is to address these issues by adding hydrogen, which has a wider flammable range and a faster laminar flame speed, to ammonia. In this study, the extension of the operable range of ammonia-fueled spark ignition engine by hydrogen addition was mainly discussed. Ammonia was injected directly in the cylinder and hydrogen was supplied into the intake port. The result showed that operable range of ammonia fueled combustion with hydrogen addition could be extended from 0.2 to 1.4 MPa with relatively stable combustion, i.e. CoV of gIMEP <5 %, except for one case. Moreover, under the BMEP 1 MPa load condition, hydrogen addition improved brake thermal efficiency (BTE) as 4.7 % and unburned ammonia also reduced by 25 %. [Display omitted] • About 5 % of hydrogen addition stabilize the ammonia engine under medium and high load. • Operable loads are extended with hydrogen addition. • Combustion duration became shorter as the load higher. • Improved combustion efficiency reduces unburned ammonia. [ABSTRACT FROM AUTHOR]

The resistive random-access memory (RRAM) with multi-level storage capability has been considered one of the most promising emerging devices to mimic synaptic behavior and accelerate analog computations. In this study, we investigated the reset-first bipolar resistive switching (RS) and multi-level characteristics of a LaNiO3−x thin film deposited using a reactive magnetron co-sputtering method. Polycrystalline phases of LaNiO3 (LNO), without La2O3 and NiO phases, were observed at similar fractions of Ni and La at a constant partial pressure of oxygen. The relative chemical proportions of Ni3+ and Ni2+ ions in LaNiO3−x indicated that it was an oxygen-deficient LaNiO3−x thin film, exhibiting RS behavior, compared to LNO without Ni2+ ions. The TiN/LaNiO3−x/Pt devices exhibited gradual resistance changes under various DC/AC voltage sweeps and consecutive pulse modes. The nonlinearity values of the conductance, measured via constant-pulse programming, were 0.15 for potentiation and 0.35 for depression, indicating the potential of the as-fabricated devices as analog computing devices. The LaNiO3−x-based device could reach multi-level states without an electroforming step and is a promising candidate for state-of-the-art RS memory and synaptic devices for neuromorphic computing. [ABSTRACT FROM AUTHOR]

Future long‐term rainfall forecasts are valuable for operating water supply facilities and managing unusual droughts. This study proposes a novel approach to forecast basin‐scale monthly rainfall from lagged global climate indices, antecedent historical rainfall data of a targeted basin, and forecasted rainfall data from a nearby basin using a data‐driven model. The approach is applied to the Han River basin and the Geum River basin, South Korea, for May and June, prone to drought occurrence. An artificial neural network (ANN), a widely used data‐driven model, was employed to build forecasting models for the study basins. Two types of ANN models were constructed: one uses predictors of the lagged climate indices and antecedent rainfall of a targeted basin that have been typically used in previous studies, and the other further uses the forecasted rainfall of an adjacent basin that was first attempted in this study by considering the strong concurrent relationship of monthly rainfall data between nearby basins. The optimal network architectures were determined through the Monte Carlo cross‐validation (MCCV) process in which repeated data subsampling for training datasets was carried out to reduce the output variance and obtain ensemble forecasts. The results show that the proposed ANN model in this study with input variables of the forecasted rainfall of the nearby basin and the lagged global climate indices and the past rainfall of the target basin provides better predictive performance than the model without using the adjacent basin's forecast rainfall. The categorical forecasting skill based on the proposed approach is good: the hit rates and Heidke skill scores ranged from 50.9 to 66.0% and 0.29 to 0.49, respectively. The results confirm that using rainfall forecasts of a nearby basin as an input variable can enhance the ANN model's ability to predict future monthly rainfall. [ABSTRACT FROM AUTHOR]

As many services convert to digital based on human-machine communication technology, older adults face considerable challenges. With the goal to identify ways to design digital services that are easier for older adults to use, this paper uses the strategy of making self-ordering kiosks more similar to the original version (i.e., paper menu) focusing on three familiarity design approaches: representation, manipulation, and organization. A 2 (skeuomorphic vs. flat design) x 2 (hierarchical vs. linear navigation structure) between-subject design experiment was conducted with individuals aged over 65 years (N = 60). Participants perceived that the skeuomorphic design was easier to use compared to the flat design, and the linear navigation structure increased perceived self-efficacy, usefulness, and intention to use compared to the hierarchical navigation structure. Participants also completed the tasks more quickly in the skeuomorphic design (vs. flat design) and linear navigation structure (vs. hierarchical structure) conditions. Interaction effects suggest that the task completion time was further reduced when skeuomorphic design was used with a linear navigation structure. Furthermore, fewer people requested assistance when they used a linear navigation structure. Serial multiple mediation results showed that the influence of linear navigation structure on intention to use was mediated by perceived self-efficacy and usefulness. • Skeuomorphic design offers better user experience for seniors than the flat one. • Linear navigation structure offers better user experience for seniors than the hierarchical one. • Combining skeuomorphism and linear structure decreases the task completion time. • The effect of linear navigation structure on intention to use is mediated by self-efficacy and perceived usefulness. [ABSTRACT FROM AUTHOR]

Boron neutron capture therapy (BNCT) is a radiation therapy that selectively kills cancer cells and is being actively researched and developed around the world. In Korea, development of the proton linear accelerator-based BNCT system has completed development, and its anti-cancer effect in the U-87 MG subcutaneous xenograft model has been evaluated. To evaluate the efficacy of BNCT, we measured 10B-enriched boronophenylalanine (BPA) uptake in U-87 MG, FaDu, and SAS cells and evaluated cell viability by clonogenic assays. In addition, the boron concentration in the tumor, blood, and skin on the U-87 MG xenograft model was measured, and the tumor volume was measured for 4 weeks after BNCT. In vitro, the intracellular boron concentration was highest in the order of SAS, FaDu, and U-87 MG, and cell survival fractions decreased depending on the BPA treatment concentration and neutron irradiation dose. In vivo, the tumor volume was significantly decreased in the BNCT group compared to the control group. This study confirmed the anti-cancer effect of BNCT in the U-87 MG subcutaneous xenograft model. It is expected that the proton linear accelerator-based BNCT system developed in Korea will be a new option for radiation therapy for cancer treatment. [ABSTRACT FROM AUTHOR]

In-cylinder flow motion is important for enhancing combustion in internal combustion engines. There are two major flow motions: tumble and swirl. Tumble enhances the flame propagation speed to spread throughout the entire cylinder. Swirl affects the behavior of diesel spray; an enhanced swirl ratio has been widely used in conventional diesel engines. Because dual-fueled combustion has the characteristics of premixed combustion from background fuels and mixing-controlled combustion from directly injected fuels such as diesel, understanding the effect of in-cylinder flow motion on combustion characteristics in dual-fuel combustion is critical. In this research, the effect of swirl in gasoline and diesel dual-fuel combustion was evaluated with different diesel injection timing conditions. As the dual-fuel combustion engine used in this research was driven by diesel spray, swirl was selected as the main flow motion rather than tumble. The effect of swirl with different diesel injection timings was investigated under low-speed and low-load conditions. The results demonstrate that increasing swirl intensity provokes fast-burning caused by the enhanced air-fuel mixture, decreasing the diesel fraction and allowing more exhaust gas recirculation (EGR) to be used for the reduction of engine-out nitrogen oxides (NOx) and smoke emissions, without reducing thermal efficiency. [ABSTRACT FROM AUTHOR]

In this study, we analyze high-spatial-resolution (0.″24) magnetograms and high-spatial-resolution (0.″10) Hα off-band (± 0.8 Å) images taken by the 1.6 m Goode Solar Telescope to investigate the magnetic properties associated with small-scale ejections in a coronal hole boundary region from a statistical perspective. With one and a half hours of optical observations under excellent seeing, we focus on the magnetic structure and evolution by tracking the magnetic features with the Southwest Automatic Magnetic Identification Suite (SWAMIS). The magnetic field at the studied coronal hole boundary is dominated by negative polarity with flux cancellations at the edges of the negative unipolar cluster. In a total of 1250 SWAMIS-detected magnetic cancellation events, ∼39% are located inside the coronal hole with an average flux cancellation rate of 2.0 × 1018 Mx Mm−2 hr−1, and ∼49% are located outside the coronal hole with an average flux cancellation rate of 8.8 × 1017 Mx Mm−2 hr−1. We estimated that the magnetic energy released due to flux cancellation inside the coronal hole is six times more than that outside the coronal hole. Flux cancellation accounts for ∼9.5% of the total disappearance of magnetic flux. Other forms of its disappearance are mainly due to fragmentation of unipolar clusters or merging with elements of the same polarity. We also observed a number of significant small-scale ejections associated with magnetic cancellations at the coronal hole boundary that have corresponding EUV brightenings. [ABSTRACT FROM AUTHOR]

The rising demand for natural gas (NG) and hydrogen, due to their lower carbon footprint and role in storing surplus renewable energy, has highlighted the focus on developing advanced storage technologies. Traditional methods like liquefaction and compression face high energy and safety challenges, prompting the exploration of new solutions. Among these, hydrate-based gas storage stands out for its environmental benefits, using clathrate hydrates to store gas with low energy consumption and carbon emissions. Furthermore, the composition of hydrates, predominantly water (∼85%), and their lack of by-products during repetitive storage–release cycles firmly establish them as environmentally friendly gas storage media. However, kinetic challenges such as stochastic nucleation, limitations in mass and heat transfer, and thermodynamic barriers arising from harsh hydrate formation conditions have hindered the practical application of hydrates. While mechanical methods to improve hydrate formation exist, their use significantly increases the demand for electrical energy. Therefore, developing methods for gas hydrate formation under static conditions is crucial for utilizing this material as a safe and green gas storage medium. This review examines theoretical studies and experimental efforts to enhance hydrate formation kinetics in static systems without additional mechanical methods. Thermodynamic hydrate promoters to increase the driving forces for hydrate formation under mild conditions, surface-modified materials to increase nucleation probabilities for shorter induction times, and porous materials to provide pathways for mass and heat transfer have been widely investigated. The discussion addresses the direction and necessary efforts for utilizing hydrate-based gas storage as a next-generation green technology. [ABSTRACT FROM AUTHOR]

A modified laser-based additive manufacturing technique, offset laser cladding was introduced to achieve dense tungsten coating on an oxide dispersion-strengthened (ODS) substrate as a plasma facing material (PFM). Different from ordinary direct energy deposition (DED) which leads to incomplete melting of tungsten and excessive melting of ODS substrate, the offset laser cladding technique can achieve complete melting of tungsten while substrate melting is suppressed. Experimental conditions (i.e., laser power, scanning speed, powder size, offset distance and injection powder nozzle setting) were carefully calculated using two validated simulation models to minimize the consumption of valuable experimental resources. Tungsten coating using the offset laser cladding in an open chamber condition showed that dense coating was achieved with a pore size of 1–2 μm. The result is comparable to that of vacuum plasma spray (VPS) tungsten coating which requires a high-level vacuum chamber. A thin interface layer (2–5 μm) was formed between the tungsten coating and ODS substrate that can alleviate thermal damage due to a large thermal expansion coefficient difference. While a small amount of surface melting was involved, the microhardness test revealed that the ODS substrate was insignificantly affected by laser heating during the offset laser cladding. • A modified DED technique, the offset laser cladding, was introduced for W coating. • W particles were fully melted while the melting of the ODS substrate was suppressed. • The laser operating parameters for W coating were designed via simulation studies. • Dense and pure W layers were coated on ODS in an atmospheric environment. [ABSTRACT FROM AUTHOR]

We present evidence that a magnetic flux rope was formed before a coronal mass ejection (CME) and its associated long-duration flare during a pair of preceding confined eruptions and associated impulsive flares in a compound event in NOAA Active Region 12371. Extreme-ultraviolet images and the extrapolated nonlinear force-free field show that the first two (impulsive) flares, SOL2015-06-21T01:42, result from the confined eruption of highly sheared low-lying flux, presumably a seed flux rope. The eruption spawns a vertical current sheet, where magnetic reconnection creates flare ribbons and loops, a nonthermal microwave source, and a sigmoidal hot channel that can only be interpreted as a magnetic flux rope. Until the subsequent long-duration flare, SOL2015-06-21T02:36, the sigmoid's elbows expand, while its center remains stationary, suggesting nonequilibrium but not yet instability. The "flare reconnection" during the confined eruptions acts like "tether-cutting reconnection" whose flux feeding of the rope leads to instability. The subsequent full eruption is seen as an accelerated rise of the entire hot channel, seamlessly evolving into the fast halo CME. Both the confined and ejective eruptions are consistent with the onset of the torus instability in the dipped decay index profile that results from the region's two-scale magnetic structure. We suggest that the formation or enhancement of a nonequilibrium but stable flux rope by confined eruptions is a generic process occurring prior to many CMEs. [ABSTRACT FROM AUTHOR]

In conducting a literature review, this article explores changes to Adult Learning and Education (ALE) policies and related processes as well as the context within which those changes have taken place, so as to draw out comparative insights regarding the unequal distribution of participation in ALE. Emphasis is on an analysis of political priorities, political-administrative guidelines, and organisational and administrative dimensions of ALE in Finland, Korea and the United States. While country-specific differences are identified, several convergences are also of importance: a priority assigned to ALE as a means to support market-driven policy, namely to enhance competitiveness in the globalised market; legislative efforts to support the demands for developing a skilled and competent workforce in the labour market; decentralised organisational and administrative structures that relate to ALE; and a decreasing trend in publicly funded ALE. [ABSTRACT FROM AUTHOR]

The Z-scheme α-Fe 2 O 3 /BiVO 4 photocatalyst was synthesized by a simple hydrothermal method. The photocatalyst is composed of α-Fe 2 O 3 nanocubes with a regular cubic structure and the BiVO 4 particles distributed on the surface of the α-Fe 2 O 3 nanocubes. The photocatalytic performance of Z-scheme α-Fe 2 O 3 /BiVO 4 photocatalyst was investigated in terms of its capacity for photodegradation of tetracycline hydrochloride. Improved photocatalytic activity was observed for Z-scheme α-Fe 2 O 3 /BiVO 4 photocatalyst compared with single BiVO 4 and α-Fe 2 O 3 nanocubes under visible light irradiation. Studies of its morphology, physicochemical properties and photoelectrochemical behaviors demonstrated that BiVO 4 loading on the surface of α-Fe 2 O 3 nanocubes forms a Z-scheme heterojunction, which increases the specific surface area and significantly promotes the separation of photoinduced carriers. The main active species were determined to be OH and h+ by ESR technique and trapping experiments. We propose a possible photocatalytic mechanism of Z-scheme α-Fe 2 O 3 /BiVO 4 photocatalyst system. This study may also provide a novel and eco-friendly demonstration of a useful strategy for the design and preparation of special structure photocatalytic materials. The Z-scheme BiVO 4 /α-Fe 2 O 3 photocatalyst was synthesized by a simple hydrothermal method. The photocatalyst is composed of α-Fe 2 O 3 nanocubes with a regular cubic structure and the BiVO 4 particles distributed on the surface of the α-Fe 2 O 3 nanocubes. The photocatalytic performance of Z-scheme BiVO 4 /α-Fe 2 O 3 photocatalyst was investigated in terms of its capacity for photodegradation of tetracycline hydrochloride. Improved photocatalytic activity was observed for Z-scheme BiVO 4 /α-Fe 2 O 3 photocatalyst compared with pure BiVO 4 and α-Fe 2 O 3 nanocubes under visible light irradiation. Studies of its morphology, physicochemical properties and photoelectrochemical behaviors demonstrated that BiVO 4 loading on the surface of α-Fe 2 O 3 nanocubes forms a Z-scheme heterojunction, which increases the specific surface area and significantly promotes the separation of photoinduced carriers. The main active species were determined to be OH and h+ by ESR technique and trapping experiments. We propose a possible photocatalytic mechanism of Z-scheme BiVO 4 /α-Fe 2 O 3 photocatalyst system. This study may also provide a novel and eco-friendly demonstration of a useful strategy for the design and preparation of special structure photocatalytic materials. [ABSTRACT FROM AUTHOR]

We studied a circular-ribbon flare, SOL2014-12-17T04:51, with emphasis on its thermal evolution as determined by the differential emission measure (DEM) inversion analysis of the extreme ultraviolet (EUV) images of the Atmospheric Imaging Assembly instrument on board the Solar Dynamics Observatory. Both temperature and emission measure start to rise much earlier than the flare, along with an eruption and formation of a hot halo over the fan structure. In the main flare phase, another set of ribbons forms inside the circular ribbon, and expands as expected for ribbons at the footpoints of a postflare arcade. An additional heating event further extends the decay phase, which is also characteristic of some eruptive flares. The basic magnetic configuration appears to be a fan–spine topology, rooted in a minority-polarity patch surrounded by majority-polarity flux. We suggest that reconnection at the null point begins well before the impulsive phase, when the null is distorted into a breakout current sheet, and that both flare and breakout reconnection are necessary in order to explain the subsequent local thermal evolution and the eruptive activities in this confined magnetic structure. Using local DEMs, we found a postflare temperature increase inside the fan surface, indicating that the so-called EUV late phase is due to continued heating in the flare loops. [ABSTRACT FROM AUTHOR]

In this research, it was investigated the energy fraction and emission characteristics of natural gas/diesel dual-fuel combustion in terms of the combustion index such as combustion duration and mass fraction burned 50% (MFB50) of a 6-L heavy-duty compression ignition (CI) engine. The reactivity gradient was varied by changing the diesel injection timing and natural gas energy fraction from 60 to 90%. Engine speed was fixed at 1,200 rpm, and the total input energy from the two fuels was maintained at 11,880 J/cycle for all six cylinders. Diesel injection timing was varied from top dead center (TDC) to 40° before TDC (BTDC) (at intervals of 10°). First, the combustion parameters were analyzed in terms of differences in reactivity gradients. The main combustion parameters considered included ignition delay, combustion duration, and MFB 50. For all cases, the indicated thermal efficiency (ITE) was analyzed with respect to the energy fractions of combustion loss, heat transfer loss, and exhaust loss, to determine the main influences on combustion duration and the MFB 50. Engine-out emission was introduced as an operating parameter associated with ITE and the various losses. These values were compared to those of neat diesel combustion conditions. [ABSTRACT FROM AUTHOR]

This study investigated the effect of varying the spark advance timing and excess air ratio (air excessive ratio; λ) on the combustion and emission of nitrogen oxide (NOx) in a hydrogen-fueled spark ignition engine under part load conditions. The engine test speed was fixed at 2,000 rpm and the torque condition was 60 Nm. Excess air ratio was varied from the stoichiometric (λ = 1) to the lean mixture condition (λ = 2.2) by throttling. The spark advance timing was controlled to determine the maximum brake torque timing (MBT) for each excess air ratio value. Subsequent to the determination of the spark advance timing for MBT, the spark timing was varied from MBT timing to top dead center. Based on the results, it is concluded that the leanest mixture condition (λ = 2.2) with MBT spark timing exhibited the highest brake thermal efficiency of 34.17% and the NOx emissions were as low as 14 ppm. • Heat release from the residual gas follows the main combustion of hydrogen mixture at λ = 1. • Thermal efficiency increased up to 34% with pumping loss reduction at λ = 2.2. • Combustion loss does not exceed 0.32% and maximum unburned hydrogen occurred at λ = 1. • The lowest NOx emissions are 14 ppm and 0.07 g/kWh at λ = 2.2. [ABSTRACT FROM AUTHOR]

This comparative study examines patterns of inequality in participation in two different types of adult learning and education (ALE) – job-related formal ALE (JFALE) and job-related non-formal ALE (JNFALE) – as related to social origins at the micro-level and three categories of social inequality at the macro-level at the macro level (economic, education, and skill inequality). Using data from the Programme for the International Assessment of Adult Competencies (PIAAC), two methods are used to analyse 19 selected OECD countries: multivariate binary logistic regressions to explore the extent to which individuals' social origins are associated with ALE participation and two-stage multilevel analysis to examine the relationship between social origins' advantages in ALE participation and social inequality. Statistically significant advantages in ALE participation of social origins were observed in some countries. Additionally, statistically significant positive relationships between social inequality and social origins' advantages in JNFALE participation are found, which implies that increases in social inequality strengthen advantages associated with social origins. [ABSTRACT FROM AUTHOR]

Background: Retropharyngeal hematoma following cervical spine trauma may lead to life-threatening upper airway obstruction and difficult airway management. This retrospective study was performed to investigate whether the extension of retropharyngeal space (RPS) was associated with difficult intubation by direct laryngoscopy in traumatic cervical spine injury.Patients and Methods: Sixty-two patients who had undergone direct endotracheal intubation under general anesthesia for cervical spine surgery were retrospectively identified. Laryngoscopic grade by Cormack-Lehane (C-L) classification was collected; grade 1 or 2 was categorized as easy laryngoscopy, whereas grade 3 or 4 was categorized as difficult laryngoscopy. In these patients, RPS thickness and the proportions of RPS to the vertebral bodies were measured at the 2nd, 5th and 7th cervical spine levels using magnetic resonance imaging (MRI) of the cervical spine. Measures of RPS were compared between easy and difficult laryngoscopy. Relationships between measures of RPS and difficult laryngoscopy were analyzed with logistic regression analysis.Results: RPS thickness at C2 was significantly greater in difficult laryngoscopy (median 14.29 mm, IQR: 9.75-18.04) than easy laryngoscopy (median 5.10, IQR: 4.33-5.94, p<0.001). Proportion of RPS to the C2 vertebral body were significantly higher in difficult laryngoscopy than in easy laryngoscopy (p<0.001). RPS thickness and the proportion of RPS to the vertebral body were significantly associated with difficult laryngoscopy (OR=2.13, 95% CI: 1.38-3.30; p<0.001 and OR=1.13, 95% CI: 1.05-1.21; p<0.001, respectively).Conclusion: RPS extension at the upper cervical spine level is associated with difficult direct laryngoscopy in traumatic cervical spine injury. [ABSTRACT FROM AUTHOR]

Abstract This study systematically investigated the application of a turbocharger system to a hydrogen spark ignition engine to extend operating limitations under high loads. The exhaust system of a commercial 2.4-L natural aspiration spark ignition engine was modified by adopting a turbocharger system. Engine test speeds were 2000–6000 rpm at intervals of 1000 rpm. The intake pressure was fixed for each experimental case, however, the quantity of hydrogen and spark advance timings were varied before the back-fire occurred. High load conditions under natural aspiration and turbocharging conditions were compared. The results indicated that distinctly higher boosts with the turbocharging system helped extend high load conditions, however, the high exhaust pressure obstructed the increasingly high load conditions under high speeds. Highlights • Power increased by up to 41% compared to N/A system with boosting at 2000 rpm. • Power decreased with boosting at 6000 rpm due to the deterioration of thermal efficiency. • Air-fuel mixture is leaner with boosting than with N/A at high engine speeds due to back-fire. • Higher pumping and friction losses with boosting resulted in lower power than those with N/A. [ABSTRACT FROM AUTHOR]

The diesel compression ignition (CI) engine has higher durability and thermal efficiency than the gasoline spark ignition (SI) engine. However, the high levels of nitrogen oxides (NOx) and particulate matter (PM) emissions are major problems of diesel engines due to the auto-ignition of heterogeneous mixtures. The dual-fuel combustion concept could be solution to environmental concerns. Dual-fuel combustion can be implemented by substituting some of the diesel fuel with high-volatility fuels, such as gasoline and natural gas. The premixed mixture condition can be improved to diminish localized rich and stoichiometric regions. Notably, ethanol has greater potential to reduce PM emissions because it is highly volatile and readily oxidized. For these reasons, in this research, the effects of varying the ethanol substitution ratio on engine performance and emissions under the dual-fuel combustion condition were experimentally investigated under various load conditions. The test engine was a heavy-duty single-cylinder diesel engine with two direct injectors. Engine speed was fixed at 1000 rpm and the load condition was varied for an indicated mean effective pressure (IMEP) ranging from 0.2 to 0.8 MPa. The ratio of ethanol to the total input energy was controlled from zero to nearly 50% of the input energy. The NOx and PM emissions decreased with increasing ethanol substitution and the mean size of the PM emissions decreased. For the mid-load condition (IMEP 0.6 MPa), the substitution was increased to 63%, but for low and high loads, higher ethanol fractions could not be used because of insufficient ignition energy at low loads and sharp increment of the in-cylinder pressure under high loads. [ABSTRACT FROM AUTHOR]

Inequality in adult learning and education (ALE) participation has been reported by previous comparative studies. In doing so, however, most of efforts have been made to understand such patterns of inequality in ALE participation at the micro-level using a conceptual approach based on human capital theory. While the micro-level approach offers an individualistic and economic perspective on learning, macro-level structural conditions play an important role in creating the circumstances faced by individuals. By performing a critical literature review, this paper intends to build conceptual foundations conducive to understand both micro- and macro-level dimensions implicitly and/or explicitly linked to inequality in ALE participation. Specifically, this paper takes a brief look into social origins as a micro-level factor, and takes an in-depth look into social inequality (i.e. education, economic and skill inequality) and institutional settings (i.e. active labour market policies and strictness of employment protection,) as macro-level factors. These conceptual foundations can be used as a conceptual framework for a cross-country empirical analysis of the degree of inequality in ALE participation. [ABSTRACT FROM AUTHOR]

Reactivity controlled compression ignition (RCCI) is one of representative dual-fuel combustion concepts for low NOx, soot emissions and high thermal efficiency. Overall lean and highly premixed auto-ignition combustion make low combustion temperature and the reduction of heat transfer loss. Although premixed compression ignition (PCI) combustion using a single fuel, i.e., diesel, also shows low emissions and higher thermal efficiency, combustion characteristics of RCCI (dual-fuel PCI) are different from single-fuel PCI due to reactivity gradient from two different fuel characteristics as well as local equivalence ratio due to the fuel distribution. Therefore, it is necessary to know the influence of above two factors on the dual-fuel combustion characteristics for better understanding of dual-fuel combustion and its effective utilization. In this research, the characteristics of dual-fuel combustion are evaluated comparing to single-fuel combustion. Also, dual-fuel combustion modes are classified according to the analysis of heat release rate (HRR) shapes. Major factors in the classification of dual-fuel combustion modes are the degree of fuel reactivity gradient and the local equivalence ratio in the cylinder. Thus, the diesel injection timing, diesel and port injected gasoline fuel ratios and the overall equivalence ratio were selected as the main variables to characterize each dual-fuel combustion mode. The result emphasizes that the dual-fuel combustion could be classified as three types by HRR shapes, and it was mainly affected by reactivity gradient and overall equivalence ratio. [ABSTRACT FROM AUTHOR]

Environmental problems have become a major issue for diesel engine development. Although emission aftertreatment systems such as DPFs (diesel particulate filters), LNTs (lean NOx traps) and SCR (selective catalytic reduction) have been used in diesel vehicles, the manufacturing cost increase caused by this equipment can be hard to be control. Thus, it is better for engine emissions to be reduced by improving the combustion system. A dual-fuel combustion concept is a recommended method to improve a combustion system and effectively reduce emissions. Low reactivity fuel including gasoline and natural gas, which was supplied to the intake port by the FPI (port fuel injector), improved the premixed air-fuel mixture conditions before ignition. Additionally, a small amount of high reactivity fuel, in this case diesel, was injected into the cylinder directly as an ignition source. This dual-fuel combustion promises lower levels of NOx (nitrogen oxide) and PM (particulate matter) emissions due to the elimination of local rich regions in the cylinder. However, it is challenging to control the dual-fuel combustion because the combustion stability and efficiency deteriorate due to the lack of ignition source and reactivity. Thus, it is important to establish an appropriate dual-fuel operating strategy to achieve stable, high efficiency and low emission operation. As a result of this research, a detailed operating method of dual-fuel PCI (premixed compression ignition) was introduced in detail at a low speed and low load condition by using a single cylinder diesel engine. Engine operating parameters including the gasoline ratio, a diesel injection strategy consisting of multiple injectors and timing, the EGR (exhaust gas recirculation) rate and the intake pressure were controlled to satisfy the low ISNOx (indicated specific NOx) and PM emissions levels (0.21 g/kWh and 0.1 FSN, 0.040 g/kWh, respectively) as per the EURO-6 regulation without any after-treatment systems. The results emphasized that a well-constructed dual-fuel PCI operating strategy showed low NOx and PM emissions and high GIE (gross indicated fuel conversion efficiency) with excellent combustion stability. [ABSTRACT FROM AUTHOR]

Resource-based cities play a crucial role in China's economic development. However, they are faced with the challenge of urban shrinkage due to the slowdown of economic growth in China, single industrial structure and the ‘boom and bust’ industrial cycle. To reverse the expected decline of these cities in the future, the Chinese Government has implemented active policies at national, provincial and municipal levels. This paper reviews the current planning policies and practices in resource-based cities in China from the macro perspective, and analyses how the Government engages with the pressing economic problems faced by resource-based cities, in particular, focussing on economic restructuring. To further analyse the policies from Central Government and the diversification of practices in local contexts, this paper presents two case studies, a petroleum mining city (Daqing City) and a coal mining city (Pingxiang City). Through discussion and an evaluation of general and place-based policies and practices for resource-based cities, this paper aims to enhance the understanding of shrinking cities in China and shed light on the policy-making of economic development for other resource-based cities in developing countries. [ABSTRACT FROM AUTHOR]

Chromospheric activities before solar flares provide important clues to the mechanisms that initiate solar flares, but are as yet poorly understood. We report a significant and rapid H $\upalpha$ line broadening before the solar flare SOL2011-09-29T18:08 that was detected using the unprecedented high-resolution H $\upalpha$ imaging spectroscopy with the Fast Imaging Solar Spectrograph (FISS) installed on the 1.6 m New Solar Telescope (NST) at Big Bear Solar Observatory. The strong H $\upalpha$ broadening extends as a blue excursion up to −4.5 Å and as a red excursion up to 2.0 Å, which implies a mixture of velocities in the range of $-130~\mbox{km}\,\mbox{s}^{-1}$ to 38 km s derived by applying the cloud model, comparable to the highest chromospheric motions reported before. The H $\upalpha$ blueshifted broadening lasts for about six minutes and is temporally and spatially correlated with the start of a rising filament, which is later associated with the main phase of the flare as detected by the Atmosphere Imaging Assembly (AIA) onboard the Solar Dynamics Observatory (SDO). The potential importance of this H $\upalpha$ blueshifted broadening as a preflare chromospheric activity is briefly discussed within the context of the two-step eruption model. [ABSTRACT FROM AUTHOR]

In this research, the effects of the propane ratio and diesel direct injection strategy on the emissions and combustion characteristics of a propane-diesel dual fuel PCCI (premixed charge compression ignition) engine were evaluated. Under low speed and low engine load, the propane ratio was varied from 30 to 70% to investigate the effect of the LHV (low heating value) fuel content in the supplied fuel (propane and diesel mixture). The EGR rate was adjusted to suit each propane ratio to ensure combustibility and restricted emissions. Early diesel injection strategies have an excellent effect on the dual fuel combustion in terms of simultaneously reducing NOx (nitrogen oxides) and PM (particulate matter) emissions. This concept is based on PCCI combustion, in which the ignition delay is longer than the diesel injection. Meanwhile, although early single diesel injection has been an effective strategy for reducing NOx and PM emissions simultaneously, it was possible to further reduce NOx emissions using an early split injection strategy with a 30% propane ratio. Additionally, when the propane ratio was 70%, the ignitibility deteriorated due to early single diesel injection, which led to a much leaner air–fuel mixture condition locally prior to auto-ignition, causing unstable combustion. As a result, a multiple injection strategy with earlier main injection and a small diesel post-injection as a triggering source was adopted to stabilize dual fuel PCCI combustion with a high propane ratio. The results emphasized that the diesel injection strategy could be adjusted to suit various propane ratios under dual fuel PCCI combustion to reduce NOx and PM emissions while maintaining thermal efficiency. [ABSTRACT FROM AUTHOR]

Environmental problems and climate change arising from waste incineration are taken quite seriously in the world. In Korea, the waste disposal methods are largely classified into landfill, incineration, recycling, etc. and the amount of incinerated waste has risen by 24.5% from 2002. In the analysis of CO2 emissions estimations of waste incinerators fossil carbon content are main factor by the IPCC. FCF differs depending on the characteristics of waste in each country, and a wide range of default values are proposed by the IPCC. This study conducted research on the existing classifications of the IPCC and Korean waste classification systems based on FCF for accurate greenhouse gas emissions estimation of waste incineration. The characteristics possible for sorting were classified according to FCF and form. The characteristics sorted according to fossil carbon fraction were paper, textiles, rubber, and leather. Paper was classified into pure paper and processed paper; textiles were classified into cotton and synthetic fibers; and rubber and leather were classified into artificial and natural. The analysis of FCF was implemented by collecting representative samples from each classification group, by applying the 14C method, and using AMS equipment. And the analysis values were compared with the default values proposed by the IPCC. In this study of garden and park waste and plastics, the differences were within the range of the IPCC default values or the differences were negligible. However, coated paper, synthetic textiles, natural rubber, synthetic rubber, artificial leather, and other wastes showed differences of over 10% in FCF content. IPCC is comprised of largely 9 types of qualitative classifications, in emissions estimation a great difference can occur from the combined characteristics according with the existing IPCC classification system by using the minutely classified waste characteristics as in this study. Implications:Fossil carbon fraction (FCF) differs depending on the characteristics of waste in each country; and a wide range of default values are proposed by the IPCC. This study conducted research on the existing classifications of the IPCC and Korean waste classification systems based on FCF for accurate greenhouse gas emissions estimation of waste incineration. [ABSTRACT FROM PUBLISHER]

Light bridges (LBs) are narrow structures dividing sunspot umbra, and their role in active region evolution is yet to be explored. We investigated the magnetic structure of the two LBs: a narrow LB (with width ∼810 km) and a considerably wider LB (2475 km) in the active region NOAA 12371. We employed: (1) the high-spatial-resolution spectropolarimetric data obtained by the Near InfraRed Imaging Spectropolarimeter (NIRIS) of the 1.6 m Goode Solar Telescope (GST) for studying the magnetic structure at the photosphere, and (2) the nonlinear force-free field (NLFFF) models, extrapolated from both the photospheric magnetogram from GST/NIRIS and from the Helioseismic and Magnetic Imager on board the Solar Dynamics Observatory, for studying the three-dimensional (3D) magnetic structure on a larger scale. Our observations reveal the presence of a field-free (or, more precisely, weak-field) region and the different velocity structures inside the two LBs. Analysis of the 3D NLFFF model shows a low-lying magnetic canopy as well as the enhanced current system above the LBs. The substantial difference between the LBs and the umbrae is found in the overall magnetic topology in that the field lines emanating from the two LBs are more twisted than that from the neighboring umbrae. [ABSTRACT FROM AUTHOR]

In this research, the effects of EGR (exhaust gas recirculation) and multiple injection strategy with two pilots on the emissions and combustion characteristics of JP-8 fueled light-duty diesel engine were systemically investigated. Also, the potential of reducing NOx (nitrogen oxides) and PM (particulate matter) emissions with JP-8 in a light-duty diesel engine was evaluated. To understand the combustion phenomenon of JP-8, two different injection modes (single injection and multiple injection with two pilots) were applied. Under the single injection mode, the difference in the ignition delay between using JP-8 and diesel fuel became clear. Differently, under multiple injections with two pilots, the ignition delays of both cases were nearly the same due to the higher in the cylinder temperature cause by the combustion of the pilot injections. Finally, under multiple injection mode, more EGR (exhaust gas recirculation) could be applied to JP-8 combustion than in conventional diesel combustion while maintaining the same mass fraction burned 50% (MFB 50) to attain the same fuel conversion efficiency. As a result, NOx and PM emissions could be reduced by half when using JP-8 without decreasing the fuel conversion efficiency. [ABSTRACT FROM AUTHOR]

A holistic approach to groundwater sustainability considers the hydrological, ecological, socio-economic and technological aspects of groundwater utilization. Exploitable groundwater should be determined by physical analysis, as well as by social compromises within a community. In this work, an integrated surface water–groundwater model, SWAT-MODFLOW, is used to examine changes in hydrological components due to various groundwater pumping scenarios in the Mihocheon watershed of South Korea. Under a total groundwater abstraction of 104 mm, which is slightly less than the amount currently permissible by law, a change in storage levels of –16 mm occurred. This abstraction value, which corresponds to 33% of the annual recharge, may be an exploitable groundwater reserve available to Cheongju City, Korea.Editor D. Koutsoyiannis; Guest editor V. Krysanova [ABSTRACT FROM AUTHOR]

In this study we compare the temporal variations of the solar, interplanetary, and geomagnetic (SIG) parameters with that of open solar magnetic flux from 1976 to 2012 (from Solar Cycle 21 to the early phase of Cycle 24) for a purpose of identifying their possible relationships. By the open flux, we mean the average magnetic field over the source surface (2.5 solar radii) times the source area as defined by the potential field source surface (PFSS) model of the Wilcox Solar Observatory (WSO). In our result, most SIG parameters except the solar wind dynamic pressure show rather poor correlations with the open solar magnetic field. Good correlations are recovered when the contributions from individual multipole components are counted separately. As expected, solar activity indices such as sunspot number, total solar irradiance, 10.7 cm radio flux, and solar flare occurrence are highly correlated with the flux of magnetic quadrupole component. The dynamic pressure of solar wind is strongly correlated with the dipole flux, which is in anti-phase with Solar Cycle (SC). The geomagnetic activity represented by the A p index is correlated with higher order multipole components, which show relatively a slow time variation with SC. We also found that the unusually low geomagnetic activity during SC 23 is accompanied by the weak open solar fields compared with those in other SCs. It is argued that such dependences of the SIG parameters on the individual multipole components of the open solar magnetic flux may clarify why some SIG parameters vary in phase with SC and others show seemingly delayed responses to SC variation. [ABSTRACT FROM AUTHOR]

Photoresponsive thin films are commonlyencountered as high performancecoatings as well as critical component, photoresists, for microelectronicsmanufacture. Despite intensive investigations into the dynamics ofthin glassy polymer films, studies involving reactions of thin filmshave typically been limited by difficulties in decoupling segregationof reacting components or catalysts due to the interfaces. Here, thinfilms of coumarin polyesters overcome this limitation where the polyesterundergoes predominately cross-linking upon irradiation at 350 nm,while chain scission occurs with exposure to 254 nm light. Spectroscopicellipsometry is utilized to track these reactions as a function ofexposure time to elucidate the associated reaction kinetics for filmsas thin as 15 nm. The cross-linking appears to follow a second orderkinetic rate law, while oxidation of the coumarin that accompaniesthe chain scission and enables this reaction to be tracked spectroscopicallyappears to be a first order reaction in coumarin concentration. Becauseof the asymmetry in the coumarin diol monomer and the associated differencesin local structure that result during formation of the polyester,two populations of coumarin are required to fit the reaction kinetics;10–20% of the coumarin is significantly more reactive, butthese groups appear to undergo chain scission/oxidation at both wavelengths.These reaction rate constants are nearly independent (within 1 orderof magnitude) of film thickness down to 15 nm. There is maximum rateat a finite thickness for the 254 nm exposure, which we attributeto constructive interference of the UV radiation within the polymerfilm, rather than typical confinement effects; no thickness dependencein reaction rates is observed for the 350 nm exposure. The utilizationof a single polymer with two distinct reactions enables unambiguousinvestigation of thickness effects on reactions. [ABSTRACT FROM AUTHOR]

Attracting significant attention from the media and policymakers, international student assessments are serving as pressures on and challenges for individual countries. Even so, paying attention only to publicly released rankings in international student assessments may lead to superficial interpretations of the assessment results. Simply equating the rankings with educational outcomes can be a questionable perspective because the assessment results can be interpreted differently. In this context, this article has explored student achievement in the Programme for International Student Assessment (PISA) tests in comparison with civic knowledge achievement in the IEA Civic Education Study across 17 countries. This article has also evaluated efficiency in educational processes by assessing outputs (student performance in PISA) against inputs (educational spending and learning time) directly used in the education system. These two approaches clarify that publicly released rankings in PISA change to some extent when the rankings are reevaluated by taking other factors into consideration. This implication should be allowed for in interpreting the results of international assessment and the relative rankings of participating countries. [ABSTRACT FROM PUBLISHER]

The key point of premixed compression ignition (PCI) combustion is an ignition delay time that is sufficient to premix the air and fuel. Thus, when PCI combustion is implemented with a single fuel, a very early start of injection (SOI) is usually applied, along with heavy exhaust gas recirculation. However, if two different fuels are used simultaneously for PCI combustion, it is possible to control the in-cylinder fuel reactivity by adjusting their ratio. Because an additional ignition delay control parameter is used for dual-fueled PCI combustion, its operating strategy and combustion characteristics differ from those of single-fueled PCI combustion. In this study, single-fueled and dual-fueled PCI combustions were compared using gasoline and diesel fuel under part-load conditions (1500 rpm and a low heating value of 580 J/str). In both cases, the diesel SOI was varied from the top dead center (TDC) to 35° BTDC to analyze the combustion characteristics. Under the optimized operating conditions, the target engine-out emissions were below the gross indicated specific NOx (gISNOx) of 0.4 g/kWh and gISsmoke of 20 mg/kWh. The results showed dual-fueled combustion is more suitable for PCI conditions than single-fueled combustion in terms of both the engine-out emissions and gross indicated thermal efficiency. • Combustion characteristics were compared between single-and dual-fueled. • Energy fraction analysis were verified under single-and dual-fueled. • Strategies for single- and dual-fueled premixed combustion were suggested. • Dual-fueled combustion was superior to single-fueled aspect of premixed combustion. [ABSTRACT FROM AUTHOR]

To draw a comparison of the effect of multiple injection strategy on the engine-out emissions under two different EGR rate conditions, the effect of pilot injection on emissions and combustion was evaluated and discussed in part 1. Thus, in the second research as part 2, the effects of post injection on the engine-out emissions were systemically evaluated for two different EGR rate conditions (30 % and 60 %). Since the behavior of diesel combustion is significantly different as EGR rate is changed, the characteristics of post injection was different between two EGR rate conditions. This research was investigated as varying injection parameters such as the timing and quantity of the post injection. The results show that the close post injection with injection interval as 10 degree has the potential to reduce PM emission, regardless of EGR rate. However, the reason of reduction of PM emission is different for each case. For a moderate EGR rate condition, close post injection with interval 10 degree enhances the fuel at bottom of bowl. Thus, the distribution of fuel can be improved. On the other hand, for a heavy EGR rate condition, close post injection with interval 10 degree has the charge cooling effect to prolong the ignition delay, rather than well-matched injection targeting. Especially, there is an effect to oxidize PM emission under moderate EGR rate condition as post injection is applied. However, post injection for late cycle of combustion under heavy EGR rate condition does not oxidize PM emission due to low oxygen concentration (∼ 10%). [ABSTRACT FROM AUTHOR]

As vehicle emissions regulations have become stricter, improving injection strategies and using high EGR rates has become important to reduce engine-out emissions. Previous research has found that, a multiple injection strategy with a pilot or post injection has the potential to improve the distribution of the air-fuel mixture or oxidation. Thus, it is important to determine the effect of multiple injection strategies on the engine-out emissions. Especially, since the latest diesel engines have used high EGR rates to reduce NO emission, the target of emissions is different from that of moderate EGR rate condition. Under heavy EGR rate condition, it is needed to improve combustion efficiency by reduction of CO and THC emissions. Therefore, in the first research as part 1, the effects of pilot injection on the engine-out emissions were systemically evaluated for two different EGR rate conditions (30% and 60%). The characteristics of the pilot injection were different between the two EGR rate conditions because the behavior of diesel combustion is significantly different when the EGR rate is changed. This research condition was investigated using varying injection parameters such as the timing and quantity of the pilot injection. The results show that each different pilot injection strategy was suggested between two EGR rate conditions to reduce engine-out emissions. Under moderate EGR rate condition, very earlier pilot SOI with large amount has the potential to reduce NO and PM emissions simultaneously. On the other hand, under heavy EGR rate condition, the closest pilot SOI to main SOI has the potential to reduce CO and THC emissions. [ABSTRACT FROM AUTHOR]

As EURO-6 regulations will be enforced in 2014, simultaneous reduction of NO and PM emissions becomes an important issue in recent diesel engine research. New combustion concepts, such as LTDC and pHCCI, have been introduced to overcome the NO and PM trade-off relation. However, these novel combustion concepts are usually implemented with a high EGR rate and by advancing the main injection timing which cause high CO and THC emissions along with poor fuel consumption due to low combustion efficiency. Therefore, the split injection strategy, which was consisted of applying post injection close to the main injection, was carried out in this experiment. Specifically, two different nozzles - a 7-hole conventional nozzle and a 12-hole double-row nozzle - were evaluated to determine the effects of nozzle configurations on engine-out emissions. The result shows that CO emission was reduced by the close post injection strategy regardless of the nozzle configuration. However, THC and PM emissions were reduced only when the 12-hole double-row nozzle was used. Thus, the use of close post injection with the 12-hole double-row nozzle could increase the combustion efficiency in heavy EGR conditions. [ABSTRACT FROM AUTHOR]

In order to achieve the dispersion stability of multi-walled carbon nanotubes (MWCNT) in a fluorinated refrigerant (FC-72) used in various cooling purposes, fluorinated MWCNT (MWCNT-F) was prepared by a combined process of oxidation and fluorination. As a fluorine source, (tridecafluoro-1,1,2,2-tetrahydrooctyl)trichlorosilane was used to react with hydroxyl groups on MWCNT (MWCNT-OH) generated by chemical oxidation. Pristine MWCNT, MWCNT-OH, and MWCNT-F were dispersed in FC-72 and MWCNT-F was also dispersed in polar and nonpolar solvents. The MWCNT-F has excellent colloidal stability in FC-72 because of the chemical affinity between FC-72 and functional groups (-CFn) on the side walls of MWCNT. Through surface modifications, we could obtain the enhanced dispersion stability of MWCNT in a refrigerant. This homogenous MWCNT solution in FC-72 may be used to increase the heat transfer in FC-72 based nanofluids. [ABSTRACT FROM PUBLISHER]

Abstract: Alumina particles were incorporated in poly(dimethyl siloxane) (PDMS) matrix in company with multiwalled carbon nanotube (MWCNT) for improving the thermal and electrical conductivities. The concentration of MWCNT was increased from 0 to 10wt% to PDMS at fixed amounts of alumina (200 and 300wt% to PDMS). Thermal conductivity of PDMS composites was increased with the increasing amount of MWCNT and the excellent dispersibility of the incorporated pristine MWCNT was achieved. Thermal and electrical conductivities of the composites were increased with the increasing concentration of the alumina because the alumina particles help disperse MWCNT within the PDMS matrix due to the ball milling effect during compounding. The properties of the alumina and MWCNT incorporated PDMS composites were investigated in terms of the curing characteristics, electrical conductivity, and thermal conductivity. The MWCNT/alumina incorporated composite showed the high electrical conductivity to the level of the semiconductor. [ABSTRACT FROM AUTHOR]

Herein, the effect of the dispersion uniformity of multi-wall carbon nanotubes (MWNTs) on the thermal conductivity of nylon 610/MWNTs nanocomposite was investigated. Compared to raw MWNTs, the carboxylated MWNTs (MWNT-COOH) were well dispersed in aqueous hexamethylenediamine solution and the dispersion stability was further improved by the presence of poly(vinyl alcohol). By means of interfacial polymerization between the aqueous hexamethylenediamine solution containing the MWNTs and a sebacoyl chloride phase, nylon 610/MWNT composites were prepared. It was found that the stable dispersion state of MWNTs in aqueous solutions greatly improved the thermal conductivity of the ultimate nanocomposites. It is noted that the thermal conductivity of nylon 610/MWNT-COOH/PVA nanocomposite was 135% higher than that of nylon 610/raw MWNTs for the same 0.1 wt% content of MWNTs. [ABSTRACT FROM AUTHOR]

In order to enhance the thermal conductivity of MWCNT filled poly(dimethyl siloxane) (PDMS) composites, the MWCNT was coated with silica layer by three step reactions. The composites filled with raw and silica-coated MWCNTs were prepared and the properties were investigated in terms of the curing characteristics, mechanical properties, and thermal conductivity. Due to the poor compatibility between raw MWCNT and PDMS, raw MWCNT showed poor dispersion uniformity and wettability in PDMS. On the other hand, due to the chemical affinity between silica/MWCNT and PDMS throughout the hydrogen bonding, the silica-coated MWCNT filled PDMS showed improved mechanical properties in terms of tensile strength and 100% modulus, and good interfacial compatibility than raw MWCNT incorporated PDMS. Finally, the good wettability of silica/MWCNT in PDMS resulted in higher thermal conductivity caused from the facile phonon movement at the interface even with the smaller MWCNT contents. [ABSTRACT FROM AUTHOR]

Abstract: Recently, the fabrication of polymer composite nanofibers containing multi-wall carbon nanotube (MWCNT) by electrospinning has attracted much attention due to their potential advantages for the enhancement of properties such as electrical and thermal conductivity. In order to utilize the superior properties of MWCNT, in this study, MWCNT was covalently grafted with poly(ethylene glycol) (PEG) chains and PEGylated MWCNT-incorporated PVA nanofibers were prepared by electrospinning. To do so, MWCNT was firstly chemically oxidized to bear carboxyl groups and successively reacted with PEG molecules in ethanol. The PEGylated MWCNT was mixed with aqueous PVA solution and electrospinning was performed. The degree of surface modification of MWCNT by PEG was thoroughly investigated by FT-IR, XPS and TGA. Compared to the pristine MWCNT, the PEGylated MWCNT was uniformly dispersed PVA nanofibers without agglomeration. Because of the enhanced dispersion of PEGylated MWCNT in PVA nanofibers, the electrical conductivity of nanofibers with PEGylated MWCNT (1.0wt%) was increased by 4 orders of magnitude compared to that of nanofibers with pristine MWCNT (1.0wt%). [Copyright &y& Elsevier]

Abstract: Herein, PEDOT:PSS/PVP nanofibers were produced by electrospinning. The presence of PEDOT:PSS in the nanofibers was confirmed by FT-Raman spectroscopy. The applied voltage-dependent diameter of PEDOT:PSS/PVP nanofibers was observed. Also, sensing behaviors of electrospun PEDOT:PSS/PVP nanofibers were explored by measuring its response upon cyclic exposure to organic vapours such as ethanol, methanol, THF, and acetone at room temperature. When PEDOT:PSS/PVP nanofibers were exposed to each solvent, the protic and aprotic solvents resulted in opposite electrical responses. These findings exhibit that electrospun PEDOT:PSS/PVP nanofibers are the promising candidate for the organic vapour sensing material. [Copyright &y& Elsevier]

Herein, PEGylated multi-walled carbon nanotube (MWNT) was prepared for the successive fabrication of poly(vinyl alcohol) PVA/MWNT nanocomposite film by solution casting. The surface modified MWNT showed a good colloidal stability in a polar solvent, i.e., water. Also, the PEGylated MWNT had an improved dispersion stability in aqueous PVA solution. The mixture of PEGylated MWNT and PVA dissolved in water was film casted and the dispersion uniformity and corresponding improvement of electrical conductivity were investigated. The electrical conductivity of PVA/modified MWNT composite film was three-fold higher than that of PVA/pristine MWNT composite film due to the much improved distribution uniformity of modified MWNT in PVA matrix. [ABSTRACT FROM AUTHOR]

Abstract: The changes of electrical resistance of the polymer composites on exposure to chemical vapors have been applied for the production of vapor sensors. In this study, to confirm the ability of silicone rubber as chemical vapors sensors, silcone/acetylene black (AB) composite film was prepared by compounding and compression molding. The responses of this elastomer composite film for various organic vapors (polar aprotic, polar protic, and non-polar solvents) were calculated by monitoring the change in the resistance of the composite film when exposed to the organic vapors. The changes of electrical resistance of the composite films are explained on the basis of volume expansion as swelling and polar interaction of various vapors on the composite. The experimental results showed that the behaviors to organic solvent vapors were considerably influenced by the temperature of the solvents and the silicone/AB composite sensor was appropriate for the detection of polar aprotic and non-polar solvents at moderate temperature. [Copyright &y& Elsevier]