Ignition Phase Research Articles

The synergistic role of sludge conditioner FeCl3/Rice husk on co-combustion with coal gangue: Thermaldynamic behavior, gases pollutants control and bottom ash stabilization

Coal processing invariably generates substantial quantities of low calorific value waste, specifically coal gangue (CG), which can be advantageously utilized by combusting to yield valuable electrical energy. However, CG incur poor ignition and flame instability, and consequently is not suited to separate combustion. The co-combustion with sewage sludge (SS) has demonstrated positive impacts on energy recovery, whereas the SS dewatering may significantly influence the co-combustion behavior. Therefore, this study systematically investigated the impact of two typical sludge conditioner, namely FeCl3·6H2O and rice husk (RH), which functions as flocculant and skeletal builder, on their synergistic role on co-combustion with CG. The thermal dynamic combustion behavior, pollutant emissions, slag tendency and bottom ash stability and toxicity were systematically studied. A robust positive synergism is observed, attributed to heat compensation and the formation of alkali metal aluminosilicates from Rh during the ignition phase. Concurrently, the temperature dependent iron oxides evolution enhances the acceleration of O2 loop, thereby promoting the char combustion. After being jointly conditioned with Rh and FeCl3, the co-combustion with CG resulted in CCi being 3.46 times higher than that of C1S3, and the average activation energy in each stage was reduced by 49.1 %. Significantly, the sludge conditioner also contributes to the reduced exhausted gases such as CO2, SO2 and NO. The Rh in SS has been found to mitigate slagging and fouling tendencies, while the retention of Cr, Cu, Ni, and Pb is greatly improved due to the stabilization of silicate minerals in CG. The Artificial Neural Network (ANN) models were established to predict the thermogravimetric experimental data of CG-SS-Rh/Fe, which aims to provide a basis for the selection of optimal operating conditions in real industrial applications.

Effect of aluminum nanoparticles size and concentration on the combustion characteristics of nanofluid fuel: Experiments and modeling

Nanofluid fuel has garnered significant attention due to its potential to enhance combustion characteristics, energy density, and ignition properties. The study comprehensively examined the effects of aluminum nanoparticles with diverse sizes (50 nm, 100 nm, 200 nm, 500 nm, 1 μm) and concentrations (2.5 wt%, 5.0 wt%, 7.5 wt%) on the ignition and combustion characteristics of nanofluid fuel droplets, utilizing a mechanically mixed aluminum-based nanofluid fuel solution that incorporated kerosene, aluminum particles, and the surfactant oleic acid. The combustion process of the nanofluid fuel droplets encompasses phases of ignition, steady combustion, micro-explosion, and agglomerate reaction. The surface temperature of the nanofluid fuel droplets consistently exceeded that of a pure kerosene droplet, with temperature elevations correlating positively with particle concentration but not with the particle size. The surface temperature of nanofluid fuel droplets containing 7.5 wt% aluminum particles is approximately 205°C. The incorporation of oleic acid into pure kerosene prolongs the ignition delay from 0.317 s to 0.333 s. The combustion rate of the nanofluid fuel droplets escalates upon the addition of aluminum particles, with the rate escalating in tandem with the diameter and concentration of the aluminum particles. Nanofluid fuel droplets containing 5.0 wt% aluminum and 5.0 wt% oleic acid particles exhibit a combustion rate akin to that of pure kerosene droplets, with rates of 0.596 and 0.604 mm2 s−1, respectively. Concurrently, the ignition delay for nanofluid fuel droplets is longer than that of pure kerosene, yet it exhibits insensitivity to particle size. The ignition delay for nanofluid fuel droplets with the addition of 7.5 wt% aluminum particles is approximately 1.5 times that of kerosene. Nanofluid fuel droplets devoid of oleic acid yield divergent results due to particle agglomeration effects. Subsequently, as particle size increased, the surface of combustion residue develops more pronounced bulges, becoming more prone to rupture. Ultimately, a kinetic prediction model is proposed, accounting for the inhomogeneous properties within the droplet. The root mean squared errors for ignition delay time, combustion rate, and steady surface temperature are all below 8 %, indicating a strong correlation between model predictions and experimental data. This research could help accelerate the adoption of aluminum-based nanofluid fuel.

Research on jet ignition phases and control parameters in an active pre-chamber optical engine under ultra-lean combustion conditions

The active pre-chamber (APC) jet ignition system is one of the primary technologies for achieving ultra-lean combustion and high thermal efficiency in engines. The impact of the jet process within the engine, as well as its control parameters, on emission pollutants (particularly soot particles) remains unclear. This study focuses on examining the effects of various low-flow injection control strategies on engine combustion and emissions by using optical experiments and numerical simulations. It also explores the impact of different ignition advance angles (ignition timings) based on a short pre-chamber mixing interval to observe ignition combustion, flame propagation, and emission characteristics under ultra-lean conditions (λ = 2.0). The main conclusions are as follows. Appropriately increasing the injection mass can enhance engine load. However, further increases in injection mass significantly raise particulate emissions, resulting in an increase in particle number by up to more than 37-fold, especially for small particles in the 5–––10 nm size range. The chemical reaction between the luminous jet flame and the bright incandescent wake jet flame, as captured by high-speed photography, effectively characterizes the various stages of jet ignition. To reduce particulate matter emissions, it is crucial to avoid the foreseeable wake jet flame caused by the enrichment of the jet mixture in the pre-chamber. The low-flow injection timing should neither be too early nor close to the ignition spark timing. The early injection causes fuel to accumulate at the top of the pre-chamber, hindering the jet flame’s propagation into the main combustion chamber. Late low-flow injection leads to fuel enrichment, resulting in uneven mixing and poor atomization and diffusion due to short mixing times. Ignition after a short mixing time interval tends to increase knocking, resulting in intense combustion and an advanced phase, which slightly reduces load and combustion stability. Regarding the heat release ratio, the total heat release from the two combustion stages in the pre-chamber should ideally account for about 5–6 % of the heat release in the main chamber.

Effect of fuel characteristics coupled with injection parameters on oil–gas mixing and combustion processes in diesel engines

The physicochemical properties of fuels are critical determinants of the in-cylinder processes, overall performance, and emission characteristics of internal combustion engines. The distinctive characteristics of various fuels during atomization, evaporation, oil–gas mixing, ignition, and combustion phases play a decisive role in determining the combustion efficiency, thermal efficiency, and formation of pollutants. This study conducts a comprehensive comparative analysis of the physical and chemical properties of five distinct fuels, focusing on their interactions with the injection parameters. This investigation delineates the influence of these properties on the spray breakup dynamics and subsequent combustion processes. Results demonstrate that while the fuels exhibit varying sensitivities to injection parameters, optimal combustion performance is consistently achieved when the injection timing is set at 22° Before the Top Dead Center(BTDC), the nozzle orifice diameter is 0.32 mm, and the beam angle is maintained at 160°. This analysis provides novel insights into the complex coupling effects of fuel properties and injection strategies on in-cylinder processes, thereby contributing to the design and development of high-efficiency, low-emission internal combustion engines.

Stage-wise kinetic analysis of ammonia addition effects on two-stage ignition in dimethyl ether

Abstract Ammonia (NH3) has gained considerable attention as a promising carbon-free hydrogen carrier fuel for internal combustion engines, but its direct use in compression-ignition engines presents challenges, often requiring high-reactivity fuels to ignite the premixed NH3/air mixture and initiate combustion. This study focuses on the ignition process of binary NH3 and dimethyl ether (DME) mixtures, as DME is a carbon-neutral, high-reactivity fuel. A key novelty of this paper is the comparison of the ignition processes of DME and NH3/DME mixtures from a temporal, process-oriented perspective, analyzing chemical kinetics across distinct ignition phases rather than focusing solely on instantaneous reactions at discrete time points. The stage-wise analysis reveals that NH3 has minimal impact on the control mechanism governing the two-stage ignition process of DME. Specifically, DME still largely depends on OH radical proliferation during low-temperature oxidation (LTO), which releases heat as the reaction progresses. As the temperature increases, LTO branching pathways gradually shift to chain-propagation pathways, reducing overall reaction activity. The reactivity and temperature rise rate of the system are then governed by the H2O2 loop mechanism before thermal ignition. However, ammonia significantly extends the ignition delay of DME by competing with OH radicals, which are critical for DME oxidation, thus inhibiting ignition. As the ignition reaction proceeds, ammonia kinetics become more involved. For example, nitrogen-containing species from NH3 oxidation, such as NO, NO2, and NH2, react with CH3OCH2 to form CH3OCHO, reducing the flux through the LTO pathway of DME. While ammonia reaction pathways also produce OH radicals, this occurs at the expense of HO2 and H radicals, leading to H2O2 formation. Overall, these findings demonstrate the substantial impact of ammonia addition on DME ignition, highlighting the need for further research to better understand NH3/DME binary fuel ignition and to optimize the design and operation of NH3/DME dual-fuel engines for improved efficiency and reliability.

Experimental study on the optimization of operating conditions for hybrid powertrain gasoline engines

With the rapid expansion of the market for hybrid vehicles, the development of dedicated hybrid powertrain engines has become an important research direction. This study focuses on the techniques to improve the fuel economy of dedicated hybrid powertrain operating conditions of 2000 rpm, 110 Nm. Turbocharging can enhance the performance and fuel economy of gasoline engines while reducing emissions. However, intake boosting increases the pressure and temperature of the mixture in the cylinder at the compression end timing, leading to a higher risk of knock, which is not conducive to the safety and fuel consumption reduction of gasoline engines. Low-temperature combustion with mixture dilution can effectively reduce the occurrence of knock and NOx emissions. In this study, the effects of EGR and VVT strategies as different dilution methods on the combustion of turbocharged gasoline engines were investigated. The experimental results indicate that both EGR and VVT can achieve mixture dilution in the cylinder, reducing the combustion temperature and thus lowering NOx emissions. Furthermore, advancing the ignition timing results in CA50 trending towards the optimal fuel consumption point, shortening the combustion duration CA10–90, and reducing ISFC. Compared to VVT, EGR can better suppress knock, leading to an earlier ignition phase CA50, a shorter combustion duration, and ultimately less fuel consumption. The research findings provide technical support for the optimization of dedicated hybrid powertrain operating conditions.

Black carbon and particle lung-deposited surface area in residential wood combustion emissions: Effects of an electrostatic precipitator and photochemical aging

Residential wood combustion (RWC) remains a significant global source of particulate matter (PM) emissions with adverse impacts on regional air quality, climate, and human health. The lung-deposited surface area (LDSA) and equivalent black carbon (eBC) concentrations have emerged as important metrics to assess particulate pollution. In this study we estimated combustion phase-dependent emission factors of LDSA for alveolar, tracheobronchial, and head-airway regions of human lungs and explored the relationships between eBC and LDSA in fresh and photochemically aged RWC emissions. Photochemical aging was simulated in an oxidative flow reactor at OH• exposures equivalent to 1.4 or 3.4 days in the atmosphere. Further, the efficiency of a small-scale electrostatic precipitator (ESP) for reducing LDSA and eBC from the wood stove was determined. For fresh emission eBC correlated extremely well with LDSA, but the correlation decreased after aging. Soot-dominated flaming phase showed the highest eBC dependency of LDSA whereas for ignition and char burning phases non-BC particles contributed strongly the LDSA. Deposition to the alveolar region contributed around 60 % of the total lung-deposition. The ESP was found as an effective method to mitigate particulate mass, LDSA, as well as eBC emissions from wood stoves, as they were reduced on average by 72%, 71%, and 69%, respectively. The reduction efficiencies, however, consistently dropped over the span of an experiment, especially for eBC. Further, the ESP was found to increase the sub-30 nm ultrafine particle number emissions, with implications for LDSA. The results of this study can be used for assessing the contribution of RWC to LDSA concentrations in ambient air.

Influence of Voltage Rising Time on the Characteristics of a Pulsed Discharge in Air in Contact with Water: Experimental and 2D Fluid Simulation Study

In the context of plasma–liquid interactions, the phase of discharge ignition is of great importance as it may influence the properties of the produced plasma. Herein, we investigated the influence of voltage rising time (τrise) on discharge ignition in air as well as on discharge propagation on the surface of water. Experimentally, τrise was adjusted to 0.1, 0.4, 0.6, and 0.8 kV/ns using a nanosecond high-voltage pulser, and discharges were characterized using voltage/current probes and an ICCD camera. Faster ignition, higher breakdown voltage, and greater discharge current (peak value) were observed at higher τrise. ICCD images revealed that higher τrise also promoted the formation of more filaments, with increased radial propagation over the water surface. To further understand these discharges, a previously developed 2D fluid model was used to simulate discharge ignition and propagation under various τrise conditions. The simulation provided the spatiotemporal evolution of the E-field, electron density, and surface charge density. The trend of the simulated position of the ionization front is similar to that observed experimentally. Furthermore, rapid vertical propagation (<1 ns) of the discharge towards the liquid surface was observed. As τrise increased, the velocity of discharge propagation towards the liquid increased. Higher τrise values also led to more charges in the ionization front propagating at the water surface. The discharge ceased to propagate when the charge number in the ionization front reached 0.5 × 108 charges, irrespective of the τrise value.

Research on nonequilibrium plasma-assisted evaporation and ignition of n-decane droplet

To evaluate the nanosecond pulsed discharge plasma-assisted evaporation and ignition attributes of hydrocarbon fuel droplets, numerical models are established. The influences of nonequilibrium plasma on the characteristics of n-decane droplet evaporation and ignition are numerically studied through a loosely coupled method employing a one-dimensional (1D) fully transient model of droplet evaporation and ignition and a model of nanosecond pulse plasma discharge. The results show that the reaction rate of the initial phase of n-decane droplet ignition is increased by nonequilibrium plasma. In addition, both the evaporation and ignition of the droplet are accelerated. Increasing the reduced electric field of the discharge leads to decreases in the droplet ignition delay time, survival time, and shortening amplitude. The evaporative cooling effect, which occurs at the initial phase of droplet ignition and typically decreases the local temperature surrounding a droplet surface, is weakened by the plasma. As the reduced electric field increases, the time to generate a high-temperature zone (>1800 K) decreases, while its duration increases. The initial phase of n-decane droplet ignition, in which the flame temperature increases while the flame radius decreases, is strongly affected by the plasma during the initial ignition phase. However, the plasma has little impact on the peak flame temperature and the flame radius during the stable combustion phase of the droplet. According to reaction kinetics analysis, the plasma directly interferes with the elementary reactions R330 (nC10H22 + O = 3-C10H21 + OH) and R331 (nC10H22 + O = 2-C10H21 + OH) of n-decane/air combustion. Moreover, the dissociation and oxidation processes of intermediate products are accelerated. Then, the important reaction rates, which determine the ignition delay time, increase indirectly. Thus, the overall ignition delay time of the n-decane droplet is shortened.

Optical study on the effect of ozone addition on a diesel/ammonia dual fuel engine with pilot injection

Influenced by the concept of carbon neutrality, ammonia is gaining widespread attention in the transport sector as a zero-carbon fuel. Diesel/ammonia dual fuel engines can achieve stable combustion of ammonia and reduce carbon emissions. To further enhance the low load combustion performance of a diesel/ammonia dual fuel engine, the effect of ozone addition on in-cylinder combustion and flame development was investigated based on an optical engine. Beyond that, ozone addition on pure diesel was also tested to understand the effect of ozone addition on diesel combustion enhancement in diesel/ammonia reactivity controlled compression ignition (RCCI) mode. The results show that the addition of ozone significantly advances the ignition phase, increases the flame area and brightness, and results in a growth in flame luminescence intensity along the radial length and closer to the center of the view field for diesel/ammonia RCCI combustion. In addition, chemical kinetic analysis shows that diesel/ammonia combustion requires higher ozone concentrations to overcome the inhibitory effect of ammonia to reach the upper limit of the promotional effect on the ignition phase and indicated mean effective pressure (IMEP), due to the large amount of OH consumed by ammonia compared to pure diesel. The promotional effect of added ozone on IMEP is similar for different pilot injection ratios (PIRs). At a low PIR and high ozone concentration, the diesel/ammonia RCCI engine achieves the highest IMEP, indicating that ozone addition combined with optimization of diesel injection parameters contributes to improve the performance of the diesel/ammonia RCCI engine at low loads.

PRELIMINARY STUDY OF DEPENDENCE OF SMOKE AND CARBON MONOXIDE EMISSION ON HEAT RELEASE RATE FROM FAST-GROWING WOOD SPECIES

The aim of this paper is to create the model for prediction of carbon monoxide release rate (CORR) and smoke production rate (SPR) from heat release rate (HRR) of fast-growing wood species. The model is independent on wood species, thus is suitable for all fast-growing wood species. Three wood species hybrid poplar J-105 (Populus nigra × P. maximowiczii A. Henry), white willow (Salix alba L.) and black locust (Robinia pseudoacacia L.) were used for universal model creation. The heat release rate, smoke production rate and carbon monoxide release rate have been measured at three heat fluxes (25, 35 and 50 kW.m-2) by the cone calorimeter. The average values of CORR and SPR for all investigated wood species were 0.051 g.m-2.s-1 and 0.086 m2.m-2.s-1, respectively. Both dependencies of SPR and CORR on HRR have shown similar trends during the ignition phase (unstable trend) and during the intense burning phase (roughly linear increasing with HRR). The main difference was shown during the steady state phase (dependency of SPR on HRR is stable while dependency of CO on HRR is highly unstable). The results also proved a significant impact of wood density on these dependencies, thus, the neural network for prediction of SPR, CORR from HRR was applied. The coefficients of determination R2 for trained neural networks, for both SPR and CORR, were achieved in the range from 0.96 to 0.97

The electrophysiological effects of Tongyang Huoxue granules on the ignition phase during hypoxia/reoxygenation injury in sinoatrial node cells.

This study was undertaken to explore the potential therapeutic effects of Tongyang Huoxue Granules (TYHX) on sinoatrial node (SAN) dysfunction, a cardiac disorder characterized by impaired impulse generation or conduction. The research question addressed whether TYHX could positively influence SAN ion channel function, specifically targeting the sodium-calcium exchanger (I NCX) and L-type calcium channel (I CaL) of the SAN. Sinoatrial node cells (SANCs) were isolated and cultured from neonatal Japanese big-eared white rabbits within 24h of birth. The study encompassed five groups: Control, H/R (hypoxia/reoxygenation), H/R+100μg/mL TYHX, H/R+200μg/mL TYHX, and H/R+400μg/mL TYHX. The H/R model, simulating hypoxia/reoxygenation stress, was induced within 5days of culture. Whole-cell patch clamp technique was employed to record currents following a 3-min perfusion and stabilization period with TYHX. TYHX administration demonstrated improvements in the ignition phase of impaired SANCs. The half-maximal effective dose of TYHX, as determined by SANC beating frequency, was found to be 323.63μg/mL. Inward current density of I NCX increased in response to TYHX (200 and 400μg/mL), while TYHX enhanced I CaL current density in H/R SANCs, with 400μg/mL exhibiting greater efficacy. Additionally, TYHX regulated the gating mechanisms of I CaL by right-shifting the steady-state inactivation curve and accelerating recovery from inactivation. Notably, TYHX increased the activation time constant under 200 and 400μg/mL, prolonged the fast inactivation time constant τ1 with 400μg/mL, and extended the slow inactivation time constant τ2 with 100 and 400μg/mL. The findings suggest that TYHX may hold promise as a therapeutic intervention for sinus node dysfunction, offering potential avenues for drug development aimed at safeguarding SAN function.

Study of the Influence of Heat Flow on the Time to Ignition of Spruce and Beech Wood

Adherence to fire safety regulations for wood is one of the most important tasks in its use in structural and architectural applications. This article deals with determining the influence of heat flux on the ignition process of spruce (Picea abies L. Karst.) and beech wood (Fagus sylvatica L.). The heat flux was generated by an electric radiant panel. The analysed parameters included the ignition time of the spruce and beech wood samples, the influence of wood density, and sample moisture, and the course of sample combustion, both with and without flame, was observed. The heat flux was maintained at constant values, depending on the distance of the examined sample from the panel, along with the specific power of the radiation panel. The power of the radiation panel was set to constant values of 5 kW and 10 kW. The samples were placed at distances of 50, 70, 100, 150, and 200 mm from the heat source, and heat fluxes in the range of 13–92 kW·m−2 were observed. At a power of 5 kW and a heat flux of 64 kW·m−2, neither the sample of beech nor that of spruce wood, placed at the distance of 100 mm from the radiation panel, exhibited flaming combustion. The ignition time for the beech wood was approximately twice that of the spruce wood, likely due to the higher average wood density. It can be stated that wood density, as one of the main factors, significantly influences the ignition phase of burning. The statistical analysis examined variables including wood type, radiant panel output, distance, and heat flux in relation to ignition time. The analysis revealed a significant difference between ignition time and distance (p-value = 0.0000, H = 37.51583) as well as between ignition time and heat flux (p-value = 0.0000, H = 37.69726). Similarly, the time to ignition for all tested beech wood samples was longer than for spruce wood.

Ignition and combustion of Al–Mg–Li alloy particles at elevated pressures

Al–Mg–Li ternary alloy particles can be a promising metal additive to replace aluminum in solid propellants to improve combustion efficiency by reducing agglomeration during combustion. In this paper, Al–Mg–Li ternary alloy was prepared and its basic physical and chemical characterization parameters were obtained by SEM-EDS, ICP-AES, and XRD analysis. The ignition and combustion characteristics of single Al–Mg–Li particles under different pressures were investigated by using a self-developed experimental setup. The ignition process and combustion flame structure of Al–Mg–Li particles were significantly affected by the increasing pressure, and the ignition delay and combustion time decreased. The ignition mode was clearly identified: surface ignition (0.1–0.2 MPa) and gas phase ignition (0.4–1.2 MPa). Al–Mg–Li particles showed white-pink flame during combustion, and the characteristic peaks of AlO, MgO, and Li were identified, confirming that the particles performed a gas-phase combustion at pressures above 0.4 MPa. The combustion temperature of Al–Mg–Li particles could exceed 3000 °C when the pressure surpassed 0.6 MPa. The composition of different regions in the condensed combustion products were analyzed. Reaction mechanism was proposed to reveal the addition of elemental Mg and Li could improve the ignition and combustion characteristics of Al, especially at higher ambient pressures.

BTEX Assessment among Informal Charcoal-Burning Food Traders for Cleaner and Sustainable Environment

This study assessed the cleaner and sustainable environment by measuring emission levels of benzene, toluene, ethylbenzene, and xylene (BTEX) from informal food traders using charcoal as the primary source of energy at a flea market in Fordsburg, Johannesburg. Volatile organic compounds (VOCs) were measured using a real-time monitor (MiniRae 3000 photoionization detector); an indoor air quality (IAQ) monitor was used to monitor environmental parameters and passive samplers in the form of Radiello badges, which were used to determine BTEX emissions from charcoal used during food preparation. Measurements were taken at 1.5 m above ground assuming the receptor’s breathing circumference using PID and Radiello. PID data were downloaded and analyzed using Microsoft Excel(Version 2019). Radiellos were sent to the laboratory to determine the BTEX levels from the total VOCs. The total volatile organic compound (TVOC) concentration over the combustion cycle was 306.7 ± 62.8 ppm. The flaming phase had the highest VOC concentration (547 ± 110.46 ppm), followed by the ignition phase (339.44 ± 40.6 ppm) and coking with the lowest concentration (24.64 ± 14.3). The average BTEX concentration was 15.7 ± 5.9 µg/m3 corresponding to the entire combustion cycle. BTEX concentrations were highest at the flaming phase (23.6 µg/m3) followed by the ignition (13.4 µg/m3) and coking phase (9.45 µg/m3). Ignition phase versus the flaming phase, there was a significant difference at 95% at a p-value of 0.09; ignition phase versus the coking phase, there was a significant difference at 95% at a p-value of 0.039; and coking phase versus the flaming phase, there was a significant difference at 95% at a p-value of 0.025. When compared to the occupational exposure limits (OELs), none of the exposure concentrations (BTEX) were above the 8 h exposure limit. The findings of this study suggest that charcoal, as a source of energy, can still be a useful and sustainable fuel for informal food traders. Shortening the ignition and flaming phase duration by using a fan to supply sufficient air can further reduce exposure to VOCs.

Measurement of laminar burning speed at high pressures using plasma affected flame

Measurements of a propagating flame are crucial to the understanding and verification of important flame phenomena. Specifically, laminar, unstretched flame speed is desired to verify complex flame behavior such as turbulence or chemical kinetic models. This data is also necessary as advanced and more efficient combustion devices operate at these high pressures where this data is less reliable from the onset of flame instabilities. This research provides laminar burning speed (Suo) and Markstein length (Lb) measurements utilizing a novel technique which incorporates flame propagation during and just after the ignition phase. The analysis utilizes a constant pressure technique where the expansion of a spherical flame is visually measured. Flame propagation of stoichiometric flame from 1 to 50 atm are examined up to a radius of 20 mm. The inclusion of early flame propagation improves the measurement of Suo through the addition of a larger data set than usually possible in the conventional method. The measurement method utilizes electrical data of the spark formation with a thermodynamic model to predict the kernel velocity and temperature which result from plasma formation. In addition, morphology of the early kernel at high pressure is reported as well as comparisons to the conventional Suo measurement.

An Experimental Study Using Canola Oil Biodiesel to Examine the Properties of a Diesel Engine with Decanol as an Additive

A naturally beneficial use of diesel is primarily threatened by the depletion of natural resources and the alarming rise in pollution levels. The majority of research conducted to date has been on the use of lower alcohols; information regarding a higher alcohol mix in canola oil biodiesel is less abundant. This study investigates the effects of adding a ternary mixture of diesel, biodiesel, and decanol as an additive to a CI engine. Diesel and biodiesel were combined with decanol to conduct tests. While the diesel concentration was maintained at 50% throughout, the decanol mixing concentrations were 10%, 20%, and 30% by volume. According to the study, as decanol concentration rises, brake specific fuel consumption falls and brake thermal efficiency rises. At full load, BTE values of 32.24% and 31.68% for pure diesel and D50COME20DEC30, respectively, were noted. The ternary blend D50COME20DEC30 BSFC was 12.89% and 20.63% lower than those of COME100 and D50COME50. Although the total heat release rate is seen to be reduced during the end phase of ignition, heat release rate is observed to increase with the expansion of decanol content in the ternary mix. NOx emissions for D50COME50 and for 10%, 20%, and 30% of decanol in the ternary blend were 1869 PPM, 1838 PPM, 1819 PPM, and 1810 PPM. Therefore, in order to increase engine performance and emissions without altering the CI engine, the present examination recommends a 30% blend of decanol, 20% biodiesel, and 50% diesel. Key Words: COME (Canola oil methyl ester), Decanol, Diesel, Performance, Combustion, Emission, CI Engine.

Lawson Criterion Analysis of D-3He Fusion Reaction

The Lawson criterion constitutes a pivotal condition for the viability of sustained fusion reactions. This study employs numerical methods and data analysis in Microsoft Excel to ascertain the Lawson criterion for D-³He fusion at temperatures ranging from 75 to 150 keV. Furthermore, the investigation examines the influence of bremsstrahlung radiation and evaluates fusion reactivity based on Hively and Bosch-Hale parameters. Hively’s reactivity value falls within the range of 1.121 × 10−22 – 6.750 × 10−22 m3/s, the instability occurs at temperatures < 100 keV. The Bosch-Hale value differs significantly from the Hively reactivity, which is 1.208 × 10−22 – 2.340 × 10−22 m3/s. The bremsstrahlung radiation within the range of 4.819 × 10−20 – 6.802 × 10−20 keV exhibits minimal impact on the reaction. The Lawson criterion value within the scope of this study typically falls within the range of 0.437 × 1021 – 1.452 × 1021 s/m3. This range signifies the necessary combination of confinement time and plasma density to facilitate the generation of clean energy within a temperature range of 75 to 150 keV, thus propelling the fusion process toward the ignition phase.

The Mobilizing Power of Visual Media Across Stages of Social-Mediated Protests

ABSTRACT The popularity of camera phones, the availability of photo-editing apps, and the rise of visually oriented social media platforms have made it convenient for citizens to produce and circulate visual content in contentious politics. While scholars have increasingly recognized the role of visuals in mobilizing social-mediated protests, how different types of visuals affect message engagement across different stages of protests remains underexplored. For this study, we analyzed approximately ten million tweets from Twitter for three social-mediated protests (Black Lives Matter, Stop Asian Hate, and Women’s March). We found that posts with images and videos generally attracted more audience engagement than their textual counterparts. Unpacking the role of visual media across different modalities and stages of social-mediated protests, we found that the superior effects of visuals were generally more pronounced during the ignition phase of the protest than the periods before and after. By applying unsupervised image clustering on millions of protest visuals, we systematically established four common visual content categories: crowd-based protest photos, non-crowd-protest human photos, non-human photos, and non-photograph visuals. We revealed heterogeneous effects on audience engagement across content categories and protests, and explored these categories through qualitative analysis of most-engaged visuals. These findings enrich our understanding of the mobilizing power of visual media in social movements and shed light on effective communication strategies regarding social inequalities.

Study on the effect of particle morphology on transient dispersion behavior and ignition of Al[sbnd]Mg alloy powder

Particle morphology has a significant effect on the explosion of energetic dust which includes heat transfer and transient dispersion behavior. This study aimed to investigate the differences in transient dispersion characteristics of Al-Mg alloy powders with different shapes using Particle Image Velocimetry (PIV) and to elucidate their effects on subsequent flame propagation and explosion parameters. The results demonstrated that irregular dust exhibited lower agglomeration and terminal fall velocity (TFV) compared to spherical dust, leading to a higher overall concentration of dust involved in the explosion. In addition, the turbulence intensity in the critical ignition zone of irregular particles was relatively high, resulting in particles having more active motion characteristics during the initial ignition phase. Therefore, irregular dust exhibited more intense flame phenomena and higher explosion parameters. These findings emphasize the importance of considering particle morphology when assessing the risk associated with metal dust explosions.