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Enriching gasoline with onboard-produced HHO presents a promising solution to enhance motorcycle engine performance and mitigate greenhouse gas emissions. However, flashback, arising from residual HHO in the intake manifold, poses a significant challenge. This study examines the distribution of the hydrogen-air equivalence ratio in the intake manifold using various HHO supplying methods: continuous induction method (CIM), discontinuous induction method (DIM), and venturi injection method (VIM). The results identify the maximum HHO flow rate for each method to prevent flashback occurrence. Supplying HHO through CIM with the nozzle located at the butterfly valve is suitable for HHO flow rates below 8 LPM, corresponding to a gasoline substitution of 7.3%. When supplying HHO through the nozzle positioned at the venturi throat using CIM and DIM methods, the maximum flow rates are 2 LPM and 5.33 LPM, respectively, corresponding to gasoline substitutions of 1.6% and 2.5%. HHO can be safely supplied at higher flow rates through the vacuum valve by controlling the pressure at the retrofitted venturi throat. With an injection pressure of 0.7 bar and an injection duration angle of 80°CA, the gasoline substitution can reach 17.7% without the risk of flashback. The CIM with the nozzle located at the butterfly valve is an appropriate solution for supplying the minimum HHO flow rate to enhance combustion characteristics. The VIM is advantageous for supplying high HHO flow rates, significantly improving engine performance, increasing gasoline substitution, and reducing greenhouse gas emissions. • Hydrogen concentration distribution near intake port mainly affects flashback occurrence. • HHO can replace safely 2.5% gasoline by discontinuous induction method at venturi. • 7.3% gasoline substitution without flashback by continuous induction HHO at butterfly valve. • Gasoline substitution can reach 17.7% with HHO injection at venturi throat. • Venturi injection method with throat pressure control is suitable for high flow rate HHO supplying. [ABSTRACT FROM AUTHOR]

Copyright of Arts for Linguistic & Literary Studies is the property of Thamar University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Aims Methods Results Conclusions Psychedelics, including mescaline, may serve as novel treatments for depression and anxiety. However, data is scarce on the safety of mescaline.The present pooled analysis included two double‐blind, randomized, placebo‐controlled studies with a total of 48 participants and 96 mescaline administrations. Single oral‐dose administrations (n = 16/dose) of mescaline at doses of 100–800 mg were used. Acute subjective and autonomic effects and acute and subacute adverse effects were recorded. Liver and kidney function, blood cell counts, and “flashbacks” were documented at the end of the studies.Positive subjective effects dose‐dependently increased and were higher than negative subjective effects for all mescaline doses. Autonomic effects increased moderately. Systolic blood pressure remained < 180 mmHg in all participants. Of all mescaline administrations, diastolic blood pressure > 100 mmHg was measured in 6%, heart rate > 100 beats/min was measured in 3% and body temperature > 38 °C was measured in 5%. The total number of acute adverse effects was 51, 12, 179, 143, 165 and 180 at 100, 200, 300, 400, 500 and 800 mg doses of mescaline, respectively. Nausea was dose‐limiting. Kidney and liver function and blood cell counts remained normal. “Flashbacks” were reported after 2% of all mescaline administrations.These findings suggest that the administration of single mescaline doses up to 800 mg are safe in a controlled clinical setting with regard to acute psychological and physical harm in healthy participants. [ABSTRACT FROM AUTHOR]

Blending a low ratio of hydrogen into traditional hydrocarbon fuels can reduce the modification in structure of existing combustors. However, even a low hydrogen ratio can increase the propensity of flashback due to the extremely high reactivity of hydrogen. Swirl number is a key parameter of swirl combustors which determines the flow structure. To design reliable gas turbine combustors for hydrogen-blended fuels, the study in the effect of swirl strength on flashback characteristic and the underlying mechanism is necessary. In this study, the flashback characteristics of premixed 30% H 2 /70% CH 4 /air flame in a bluff-body swirl burner is investigated via both experiment and large-eddy simulations with the flamelet-generated-manifold method (FGM-LES). The flashback mode and flame-flow interaction are analyzed based on the LES results. It is found that the increase in swirl strength will increase the propensity of flashback and promote the flashback speed of premixed 30% H 2 /70% CH 4 /air flame in the bluff-body swirl burner. The turns from Mode II (small-scale flame bulges leading flashback) to Mode I (large-scale swirling flame tongue leading flashback) during flashback of hydrogen-blended flames due to the production of stronger reversed flow by swirling flow. It is also found that stronger swirl strength will result in a smoother flame front and narrower strain rate distribution range which suppresses the local hydrogen enrichment due to preferential diffusion of hydrogen, thus suppressing the flame propagating speed. However, this effect is not dominant in flashback process compared to the promotion of reversed flow by increased swirl strength. • Efficient FGM tabulation including heat loss and differential diffusion for premixed hydrogen/methane flame is applied. • The flashback processes of premixed hydrogen-blended flame in experiment were reproduced well through FGM-LES. • The interaction between swirl strength and preferential diffusion of hydrogen was investigated. [ABSTRACT FROM AUTHOR]

This research addresses an important aspect of narrative structure: time, which serves as the backbone of novel construction. The study applies this concept to the novel When the Jar Shattered. Through this research, we will explore the novelist's ability to employ this technique in his work, analyzing how he utilized time shifts and whether these temporal jumps kept the reader eager to continue the story or if they hindered engagement. Additionally, the study examines which temporal techniques dominate the narrative stru

The numerical simulation method is used to study the influence of the mixing ratio of methane/hydrogen mixture on the combustion characteristics and pollutant emission characteristics of the combustor. The results show that due to the action of combustion chemical reaction, there exists a certain difference in the structure of cold and hot flow fields. The flow velocity of the hot flow field increases, and the recirculation zone becomes larger. The hydrogen content has a significant impact on the structure and temperature distribution characteristics of the hot flow field, and a central recirculation zone is formed when the hydrogen content is less than 20%, which can maintain stable combustion. When the hydrogen content is greater than 40%, the central recirculation zone disappears, the external recirculation zone is extended, and the spontaneous combustion and flashback occur to varying degrees. As the inlet air temperature increases, the spontaneous ignition phenomenon becomes more obvious, and the inlet air temperature decreases, the flashback phenomenon becomes more obvious. NOx emissions increase with the increase of hydrogen content, CO emissions decrease with the increase of hydrogen content, and CO is concentrated in the combustion zone of the main combustion stage.

Copyright of Journal of Shanghai Jiao Tong University (1006-2467) is the property of Journal of Shanghai Jiao Tong University Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Herbicide flashback is an undesirable response that results in damage or mortality of non-target plants near chemically treated plants. In severe instances, crop trees can be injured resulting in financial loss or inability to capture management objectives. Land managers need to know the potential limitations of using triclopyr acid (50% solution in water) and what quantity can cause damage to non-target trees (trees not aimed at for control via herbicide). Three naturally regenerated (previously clearcut) bottomland hardwood sites, ranging from 14–20 years of age, received partial overstory deadening using Trycera® herbicide. Residual "leave" trees experienced indirect herbicide uptake resulting in some trees either experiencing mortality or partial mortality with top dieback/epicormic branching. An increased probability of damage occurred as tree diameter decreased and the number of treated stems around the non-target stems increased. American sycamore, green ash, and sweetgum were most susceptible to flashback. This study examines the unanticipated chemical effect of deadening adjacent stems surrounding residual leave trees in poorly drained soils. [ABSTRACT FROM AUTHOR]

Copyright of Larq Journal for Philosophy, Linguistics & Social Sciences is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Fotocinema is the property of Revista Fotocinema and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper aims to explore how time performs in Buddhist Jataka stories by analysing Culladhammapāla Jataka (No.358) which portrays the complexity of jealousy. Through textual analysis of the above Jataka, the study finds that time functions as the thread that combines the narratives in the cycle of birth. Further, the phenomenon of time in the Jataka philosophically conveys a universal experience of morality, karma, jealousy and impermanence to the audience in any context across time. Moreover, the use of flashbacks, foreshadowing and repetition as techniques of using time gives the reader a sense of the character’s past experiences and future destinies while aggravating the impact of the narrative on the audience.

The purpose of this work is to investigate the effects of adding hydrogen to the fuel on the combustion induced vortex breakdown flashback phenomenon in a combustion chamber. An atmospheric research burner is selected for studies and the analysis is performed using numerical simulations. In order to model the turbulence-chemistry interactions, the EDC combustion model is utilized and the GRI 2.11 reaction mechanism is used to investigate the combustion process as carefully as possible. The present studies are performed keeping the exit temperature constant. To do this, by adding any amount of hydrogen to the premixed inlet flow, the methane is decreased by using the trial-and-error until the mass averaged exit temperature remains almost constant. The purpose of applying this limitation is to keep the cycle operational condition unchanged that is important for adding hydrogen to the existing combustion chambers especially from technological viewpoint. In addition, the thermal NO x production is controlled. In the following, the effect of hydrogen addition on the flame thickness and flame shape is investigated and finally, the effect of operating pressure on the flashback behavior is analyzed. • Effect of hydrogen addition to the fuel on the combustion induced vortex breakdown flashback is investigated. • The studies are performed keeping the exit temperature constant. • By adding hydrogen and reducing methane, the equivalence ratio decreases but the flame moves upstream. • Adding hydrogen reduces the flame thickness, but at higher hydrogen percentages, flame thickness will no longer depend on hydrogen addition. • It is illustrated that increasing the pressure moves the upstream in both pure methane and hydrogen-methane fuels. [ABSTRACT FROM AUTHOR]

The growth of hydrogen as an alternative clean fuel for fulfilling thermal energy needs of multiple economic sectors globally requires access to reliable, safe, energy efficient, emission free combustion technology. The work described in this short communication shows the applicability of a novel heterogeneous combustion design in utilizing a wide range of hydrogen blended methane concentrations to cleanly and safely generate thermal energy. The utilization of a simple first principles design approach along with engineered materials yielded a fuel-flexible hybrid infrared-convection burner design capable of lowering NOx emissions by more than 95% while simultaneously improving the heat transfer efficiency by 15% with a wide range of hydrogen concentrations. The safety and performance of the combustion design was demonstrated in an burner at capacities of up to 12,000 Btu/h in producing temperatures of 900 °C. The atmospheric burner concept was integrated in a cooktop configuration with combined thermal power rating of 30,000 Btu/h and operated with hydrogen blended natural gas. • Safe combustion of hydrogen-blended methane compositions was achieved. • Infrared thermal output lowered the NOx emissions by 90% compared with a conventional blue flame burner. • Safe combustion with hydrogen blends is enabled by the tortuous path of the heterogeneous media. • Heat energy utilization efficiency was enhanced by up to 15% due to radiative heat transfer. [ABSTRACT FROM AUTHOR]

The effect of centerbody heating by the flame on flashback propensity is experimentally investigated. The burner is technically premixed with 100% hydrogen as fuel under atmospheric pressure. The centerbody temperature was monitored by thermocouples revealing a thermal runaway of the centerbody temperature at the onset of flashback. Post-processed OH*-chemiluminescence imaging data of the flame show an increase in OH*-chemiluminescence intensity during thermal runaway indicating either less quenching or auto-ignition events of hydrogen/air mixtures being in contact with the heated centerbody surface. The authors recorded the formation of an auto-ignited flame kernel upstream of the flame front. An analytical model involving an auto-ignition Damköhler number D a A I , the Reynolds number R e and the normalized burner pressure drop Δ p b u r / Δ p b u r r e f is introduced predicting whether thermal runaway takes place under certain operating conditions. Experimental data from two different burners are applied to the model's safety map and good agreement is found. • A flame attached to the centerbody can lead to thermal runaway. • Auto-ignition is the dominant flashback mechanism if thermal runaway occurs. • A Damköhler model has been developed predicting whether thermal runaway takes place. [ABSTRACT FROM AUTHOR]

Liquefied petroleum gas (LPG) is considered one of the gases widely used in many industrial and residential sectors. Still, due to its different compositions, mainly propane (C3H8) and butane (C4H10), it can have other combustion characteristics. This paper aims to conduct an experimental analysis to study the impact of LPG composition on the stability map (limits of blowoff and flashback) of the premixed flame in a tangential swirl burner. Four LPG mixtures were used with different proportions of ethane (C2H6), propane (C3H8), butane (C4H10), and pentane (C5H12). Three burner nozzles at diameters of 20, 25, and 30 mm have been used, which gave three swirl numbers of 0.918, 1.148, and 1.377, respectively. The results indicate that increasing the swirl number (S) from 0.918 to 1.377 for all LPG mixtures accelerated the flashback propensity (getting worse) while the blowoff resistance improved; thus, a rising S gave a better stability map. As for the effect of the LPG composition, it was found that the maximum flame temperature was for the LPG mixture containing high percentages of butane (C4H10), while the lowest was for the mixture containing fewer percentages of butane. Changing the LPG composition had an apparent effect on the flashback limits and a slight effect on the blowoff limits; it was found that mixtures containing high percentages of butane increased flame speeds and increased the flashback propensity. Compared to LPG mixtures, the flame stability map was widest for LPG mixtures containing lower percentages of butane. Therefore, LPG with propane (C3H8) proportions higher than butane (C4H10) reduces flame temperature, flame speeds, and flashback propensity, thus improving the stability map.

Liquefied petroleum gas (LPG) is considered one of the gases widely used in many industrial and residential sectors. Still, due to its different compositions, mainly propane (C3H8) and butane (C4H10), it can have other combustion characteristics. This paper aims to conduct an experimental analysis to study the impact of LPG composition on the stability map (limits of blowoff and flashback) of the premixed flame in a tangential swirl burner. Four LPG mixtures were used with different proportions of ethane (C2H6), propane (C3H8), butane (C4H10), and pentane (C5H12). Three burner nozzles at diameters of 20, 25, and 30 mm have been used, which gave three swirl numbers of 0.918, 1.148, and 1.377, respectively. The results indicate that increasing the swirl number (S) from 0.918 to 1.377 for all LPG mixtures accelerated the flashback propensity (getting worse) while the blowoff resistance improved; thus, a rising S gave a better stability map. As for the effect of the LPG composition, it was found that the maximum flame temperature was for the LPG mixture containing high percentages of butane (C4H10), while the lowest was for the mixture containing fewer percentages of butane. Changing the LPG composition had an apparent effect on the flashback limits and a slight effect on the blowoff limits; it was found that mixtures containing high percentages of butane increased flame speeds and increased the flashback propensity. Compared to LPG mixtures, the flame stability map was widest for LPG mixtures containing lower percentages of butane. Therefore, LPG with propane (C3H8) proportions higher than butane (C4H10) reduces flame temperature, flame speeds, and flashback propensity, thus improving the stability map. [ABSTRACT FROM AUTHOR]

Air-fuel premixers are integrated parts of the premixed burner systems. The present paper describes the modeling, design optimization, and testing of an air-fuel premixer for a 5 kW natural gas porous media burner. The design was aimed at decreasing NOx and CO emissions by forming a homogeneous mixture of air and fuel. The design parameters were optimized employing CFD analysis coupled with a design of experiments (DOE) method. Then, a test model, based on the optimized design, was built and installed in a porous media burner testing apparatus. The test results have shown that the new premixer successfully reduced NOx emissions. It also improved flame stability by preventing flashback in several cases which revealed a new flashback mechanism in such burners. This improvement is achieved by preventing locally near-stoichiometric zones with high flame speeds from being formed. The effect of the new premixer on CO emissions was shown to depend on the firing rate and equivalence ratio. While reduced CO emissions are achieved at high firing rates and equivalence ratios, the level of CO emissions is increased for low firing rate and equivalence ratio magnitudes. [ABSTRACT FROM AUTHOR]

Dysfunctional mental imagery is integral to the maintenance of many psychological disorders and is typically associated with stronger affective and behavioural responses than verbal cognitions. This finding extends itself to the high prevalence of suicidal mental imagery in disorders such as depression and bipolar disorder. Imagery Rescripting is a therapy approach which has been found to effectively reduce dysfunctional mental images across various mental health conditions. Thus, Imagery Rescripting of suicidal mental imagery may be effective at reducing such cognitions and ultimately associated risk. However, this remains an unexplored area within the treatment literature. This paper puts out an urgent call for clinical research to evaluate the effectiveness of such a treatment intervention, and to assist, we propose and describe a clinical approach to this to stimulate further thought and research. There are also many research questions of clinical relevance that must be explored in this field of work, which we put forward and consider in this commentary piece. What is already known about this topic: Mental imagery is a form of cognition that generates stronger emotional responses compared to verbal-linguistic thinking and is integral to the maintenance of most psychological disorders. Cognitive Behavioural Therapy (CBT) approaches are typically more effective when mental imagery techniques – such as Imagery Rescripting (ImRs) – are incorporated to target intrusive, distressing mental imagery. Mental images of suicide (comprised of both flash-back and/or flash-forward mental images) are more distressing, realistic and promote suicidal behaviours more than verbal thoughts, and are common in disorders such as depression and bipolar disorder. What this topic adds: Urgent clinical research is needed to evaluate the effectiveness of ImRs at reducing intrusive suicidal mental images, and thus related risk, and this paper proposes and describes an approach for researchers to use as a framework. There are several clinical research considerations to be made when examining ImRs of suicidal mental images, including around the delivery and safety of the intervention. More research is needed to clarify the above clinical considerations, and to further understand change mechanisms, to learn the most safe and effective ImRs approach. If ImRs is found to be effective at reducing suicidal images in upcoming clinical trials, it is strongly recommended clinicians receive adequate training and ongoing clinical supervision from an experienced practitioner given the complexities around this approach. [ABSTRACT FROM AUTHOR]

Objectives: This study reports on four similar studies intended to explore the acceptability, safety, and efficacy of the flash technique (FT), a method of rapidly reducing the intensity of a disturbing memory or image, with minimal subjective disturbance for subjects during the process. Of the four studies, two were conducted during FT trainings in the United States, one in Australia, and one in Uganda. Methods: The studies involve pre-, post-, and follow-up repeated-measures design to determine the effectiveness of a 15-min FT intervention. A total of 654 subjects were asked to think of a disturbing memory and then participate in a structured experience of an FT. The purpose of this investigation was to determine whether a brief application of an FT would be safe and effective in significantly reducing their disturbance. In each study, subjects rated their disturbing memories on a 0-to-10 scale, with zero representing no disturbance at all and 10 representing the worst they could imagine. Then, they took part in a 15-min group practicum where they were guided in a self-administering FT with no individual supervision or support. Results: In all four studies, the mean reduction in disturbance exceeded two-thirds, the results were significant (p < 0.001), and the effect size was very large. Of the 813 sessions (654 subjects) represented in these studies, only two subjects reported slight increases in disturbances, and both of these subjects reported reductions in disturbance in their second FT experiences 2 h later. At a 4-week follow-up, mean disturbance levels in all four studies indicated maintenance of benefit or slightly further reduction of mean disturbance levels. An 18-month follow-up study with a subgroup of subjects who initially reported a high level of memory-related distress found similar maintenance of gains as well as symptom reduction. Conclusion: These findings provide preliminary evidence of acceptability, safety, and efficacy of FT; therefore, further study is warranted. [ABSTRACT FROM AUTHOR]

In this paper, we analyze the movie titled Pain and Glory, filmed in 2019 by the famous Spanish director Pedro Almodovar. According to Labarthe (2022), this is both his most personal and intimate work. The plot follows the story of a film director and screenwriter who reminisces about his life, his temptations, and expectations after achieving success and fame. For the purposes of this paper, we understand the movie as a text that is based on a script, and in our analysis, we are paying particular attention to the flashbacks. A flashback represents a technique of placing the action into the past, as, for instance, in this Almodovar's movie, the main character reconstructs his life through episodes from different life periods. We find that the most frequent flashbacks are from the period of Salvador's childhood, that is, the period of fifty years prior to the main plot's timeline. Apart from the flashbacks and memories, we also find the characters revisiting the past dialogically, i.e., in a conversational form. The pain to which the title of the film alludes is both physical and mental, demonstrating that fame is inevitably accompanied by pain. Since we find correspondence between the real life of the director himself and the life of the main character, we also analyze the examples of autofiction in this movie. Furthermore, Almodovar's universe explores the relationship between a mother and a son, while the father is barely mentioned. With this film, Almodovar erases the boundaries between reality and fiction and rewrites them. Always on the edge of the truth, the director comments that the described events are fictitious, consistent with the context, though their occurrence seems plausible. [ABSTRACT FROM AUTHOR]

This article explores how the first five years of Netflix Originals dramatic storytelling fit the “Complex TV” label that Mittell defined, with its innovative season-drop delivery strategy. We focus on one narratological device: the delimited flashback, the predominant type of analepsis in the 33 pilot episodes that made up our sample. Although the delimited flashbacks analyzed are semantically diverse, the discussion combines quantitative data with a qualitative analysis focusing on three key elements: the objects and places that trigger the characters’ memories, the contradictory or parallel relationship between timeframes, and the violation of boundaries between narrative layers. [ABSTRACT FROM AUTHOR]

This article explores how the first five years of Netflix Originals dramatic storytelling fit the “Complex TV” label that Mittell defined, with its innovative season-drop delivery strategy. We focus on one narratological device: the delimited flashback, the predominant type of analepsis in the 33 pilot episodes that made up our sample. Although the delimited flashbacks analyzed are semantically diverse, the discussion combines quantitative data with a qualitative analysis focusing on three key elements: the objects and places that trigger the characters’ memories, the contradictory or parallel relationship between timeframes, and the violation of boundaries between narrative layers.

This article presents an experimental analysis investigating the impact of swirl number (S) and annular passage area (B) on the stability limits of the premixed flames in a 20-kW tangential swirl burner. Three nozzles with different diameters (DN = 20, 25, and 30 mm) were used to achieve variable geometric swirl numbers (Sg = 0.918, 1.148, and 1.377). Three central fuel injectors (as a bluff-body) with different diameters (Dinj = 6, 8, and 12 mm) were used to obtain different annular passage areas. In the first part of the study, the results revealed that as swirl number (S) increased, flashback limits (FB) decreased (i.e., worsened), and the flame resistance to blowoff (BLO) improved. Thus, the best flame stability map was obtained with increasing S. In the second part of the study, changing the central fuel injector diameter (bluff-body) led to a change in the annular passage area (B) and had an important role in resisting and preventing flashback from combustion-induced vortex breakdown (CIVB). When B was increased (increasing fuel injector diameter), a significant improvement in flashback resistance was observed due to an increase in the momentum of the unburned mixture, while with a decrease in B (reducing fuel injector diameter), the limits of the flashback decreased and moved towards lean regions. However, it was found that the burner operation map increases with increasing B; the best operation map was found at S = 1.377 and B = 0.4, and it was (ϕFB = 1.18 - ϕBLO = 0.42) in the inlet tangential velocity range (Winlet= 0.58 to 2.84 m/s). Also, tests were carried out without the use of a bluff-body (central fuel injector), and it was found that there is a great impact on the flow field and the location and shape of the central recirculation zone (CRZ); thus, the stability map was narrower than that using the bluffbody. Consequently, adding bluff-bodies to swirling flows improves the mixing properties, increases the intensity of the CRZ, thus enhances the stable operation map. In addition, the bluff-body's presence greatly helps in eliminating CIVB flashback. [ABSTRACT FROM AUTHOR]

Hydrogen as an essential part of future decarbonization of the energy industry makes it a crucial necessity to replace conventional, natural gas based concepts in gas turbine combustion. This paper presents an experimental study of a multi-tube jet flame burner. The study is carried out with natural gas and pure hydrogen fuel at gas turbine relevant conditions at atmospheric pressure. To identify key differences between hydrogen-air and natural gas-air flames on the overall robustness and flame flashback behavior, air bulk velocity (80-120 m/s), adiabatic flame temperature (1235-2089 K) and air inlet temperature (623-673 K) are varied over a wide range, covering a range of Reynolds numbers of 10,000-20,000. Depending on flame temperature, two different flame shapes are observed for natural gas-air flames. The shape of the hydrogen-air flame changes less over the range of flame temperatures tested, but is generally more compact. The process of fuel-air mixing is further investigated by concentration distribution measurements in a water tunnel setup. Therefore, planar laser-induced fluorescence is utilized for visualization. The measured concentration distributions confirm the overall good mixing quality but also give an explanation on the observed flashback behavior of the different burner designs at reacting tests. The findings of the study are composed in a flashback correlation combining the observed flashback drivers for the burner configurations investigated. [ABSTRACT FROM AUTHOR]

Roman Polanski's An Officer and a Spy (2019) represents France of La Belle Époque not through cafés, cabarets, and literary salons but as a military state of dilapidated army offices filled with half-asleep soldiers, dust, stink, and clouds of suspicion. The Third Republic seems suspended between its revolutionary past and the bleak present: the lost war with Germany and constant governmental scandals. The country recedes into the interior to try less grandeur methods like plotting, spying and surveillance. Polanski recounts the era through the Dreyfus Affair (1894-1906), treated not as a designed plot but as a logical outcome of the bureaucratic system of the state. I analyse An Officer and a Spy historically alongside Walter Benjamin's writing on the interior. Benjamin's interior is a complex space that can function as a protective space, a space of death or inertia, a space of history and action as well as a colonising space that brings together the far and the near through colonial objects and customs. [ABSTRACT FROM AUTHOR]

Experimental study is performed to investigate the dynamic response characteristics of the flame when global equivalence ratio increases suddenly during the condition transition in a cavity-based scramjet combustor. High-enthalpy supersonic flow enters the combustor on conditions that Mach number, stagnation temperature, and total pressure are 2.52, 1486 K, and 1.6 MPa, respectively. In this paper, more attention is paid to the characteristics of flame evolution after sudden increase of fuel injection pressure and combustion characteristic when the injection pressure gets stabilized again. Three flame modes after condition transition have been observed and analyzed according to the transient chemiluminescence image captured by high-speed photography. There are two kinds of stable flame modes after transition mission at a low injection pressure difference, which are mainly reflected in the distribution of flame and intensity of visible light. Whereas, once the injection pressure difference exceeds a critical value, intense periodic flame flashback phenomenon begins to appear in the combustor. It can clearly capture the back and forth motion of the flame in the combustor, along with the local blowout and reignition phenomenon. Furthermore, the dominant frequency of flame flashback decreases and contrast of combustion intensity becomes more obvious as the injection pressure difference increases. • The highlights of this article are listed in the following: • The dynamic response characteristics of flame when equivalence ratio increases suddenly during condition transition in scramjet are investigated experimentally. • Three flame modes after condition transition have been observed and analyzed. • The effect of injection pressure difference on combustion characteristics is explored. [ABSTRACT FROM AUTHOR]

Large-Eddy Simulations were performed to study the flashback-induced flame shape transition of a lean premixed M flame in a staged liquid-fuelled aeronautical lean-burner, as observed experimentally. The BIMER combustor is a Lean Premixed Prevapourised (LPP) burner composed of two stages, each with its own injector and swirler: the main outer stage, called multipoint, uses jet-in-crossflow injection to achieve the LPP regime, while the central stage, called pilot, uses a pressure swirl injector to create a hollow cone spray to stabilise the flame. During LPP operation, this M flame presents a strong acoustic activity, promoting a periodic flashback of its leading edge. When, aiming to stabilise the flame, the pilot injection is increased and the multipoint injection decreased, the oscillating leading edge (due to the longitudinal acoustic perturbations) attaches to the pilot spray, changing the flame into a Tulip shape. Two phenomena were identified as being the most relevant causes of this flame shape transition. First, the leading edge position and the thermoacoustic instability amplitude are directly linked to the combustion chamber final temperature. The higher the temperature in the chamber, the more upstream the leading edge stabilises, and the higher the acoustic oscillation amplitude, both increasing the risk of a successful flashback. Second, the injection regime with high pilot injection allows the leading edge to attach to the pilot spray, as the flame only transitions when the pilot spray is sufficiently high. The higher the pilot fuel flow, the higher the amount of fuel sprayed in the critical region where the flame might attach for a transition to the Tulip shape. Therefore, as the change in injection regime is the main mechanism lean staged burners use to reduce emissions while increasing operability, this works shows that an M flame is unsuitable to such burners with similar aerodynamic topology and properties. [ABSTRACT FROM AUTHOR]

One of the major challenges of applying hydrogen (H 2) enriched fuels in industrial combustion systems is the risk of flashback that can cause considerable damage on combustors and affect pollutant emissions. While flashback has been extensively investigated, comparatively less analysis is made to understand the impact of thermal boundary conditions on flashback of bluff-body swirling H 2 enriched flames. The aim of this work is to fill a part of this gap through large-eddy simulations of premixed 95%H 2 /5%CH 4 -air flame flashback in a bluff-body swirl burner. The results show that flashback characteristics are very sensitive to the bluff-body thermal boundary condition. At T wall = 350 K, flashback is led by a large-scale swirling flame tongue (Mode I) that can cause the deflection of streamlines ahead of the flame front and is responsible for flashback Mode I, while a small region of negative velocity induced by small-scale flame bulges cannot lead to a net upstream propagation of the flame front. However, when treating the bluff-body as an adiabatic wall, the flashback is led by multiple small-scale flame bulges, and the circumferential motion of the lowest flame tip is negligible (Mode II). These small-scale bulges can cause large reverse flow pockets and formation of a stagnation point ahead of the preheat zone that facilitates flashback, similar to non-swirling channel flashback. This is the main mechanism responsible for flashback Mode II. At T wall = 500 K, flashback is led by different structures, switching between Mode I (upstream propagation of swirling flame tongue) to Mode II (upstream propagation of non-swirling flame bulges). Furthermore, it is found that as the boundary heat loss increases, the axial flashback speed decreases, while the azimuthal flashback speed increases due to the presence of Mode I. The results open up the possibility of extending the flashback limit of H 2 enriched swirling flames by controlling the thermal condition of bluff body. [ABSTRACT FROM AUTHOR]

Hydrogen has been identified as a potential tool for decarbonizing various industrial sectors by replacing natural gas while maintaining the combustion-based conversion system. However, due to its high reactivity, hydrogen is prone to flashback, making it essential to implement safety measures for its efficient use in practical appliances. This study investigates the flashback of different H 2 /CH 4 mixtures at an equivalence ratio φ = 0.8 and proposes a numerical model to predict the critical flashback velocity for laminar premixed flames. The model considers the conjugate heat transfer between the gas phase and the burner plate. To overcome the computational cost needed to resolve both gas and burner heating, different time steps are employed for the fluid and the solid domains. Two flashback regimes are identified depending on the H 2 content. The results suggest that using the laminar flame speed alone is inadequate for designing the safe operation of practical premixed burners. • 2D unsteady simulations of H 2 -enriched flames with detailed kinetics to estimate flashback. • Conjugate Heat Transfer fundamental to predict flashback. • Flame quenching instead of flashback, for low hydrogen contents. • Different flashback regimes for different H 2 contents. • Critical flashback velocity much different from laminar flame speed at high H 2 contents. [Display omitted] [ABSTRACT FROM AUTHOR]

Copyright of Alustath is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Development of models that can help predict flashback limits of premixed flames at an affordable computational cost is essential for the safe and efficient design of combustion chambers. For flames with strong preferential diffusion effects, usually the focus has been on the development of at least a three dimensional flamelet database that can predict the enthalpy and mixture fraction mapped on to the reaction progress variable. However, in this study, we show that a 3D FGM table is sufficient to predict flashback limits for lean laminar methane-air flames but is not sufficient to predict the same for lean hydrogen flames and an over-prediction of 100% could occur in the calculation of the flashback limits. We trace the root cause of this over-prediction to be related to the thickness of the reaction zone in the progress variable for hydrogen flames. This results in the development of a novel correction factor for the progress variable source term using 1D flame simulations where the flame experiences strong enthalpy gradients. In the end, we successfully show for the first time that the flashback limits for hydrogen flames can be predicted accurately using flamelet generated manifolds with a source term corrector function. [Display omitted] • First study with estimation of flashback limits with flamelet generated manifolds. • Flashback limits for methane-air flames are predicted in a good manner. • Hydrogen flashback limits are over-predicted with a 3D manifold. • The difference is caused by enthalpy gradients across thick reaction zone. • A simple correction model is proposed which improves the model for hydrogen flames. [ABSTRACT FROM AUTHOR]

Smoldering of polyurethane foam continues to attract the attention of the fire community because of its potential of causing severe fire hazards. Our previous work observed a unique flashback phenomenon denoting the reversal spread of horizontal smoldering front. This work further develops a one-dimensional model of foam smoldering via Gpyro to examine the flashback mechanism. The model adopts a 6-step reaction scheme consisting of two pyrolysis and four oxidation reactions based on thermogravimetric analysis. Comparison with the experimental results indicates that the computational model successfully reproduces the flashback phenomenon and explains the flashback mechanism. From the view of chemical kinetics, the initial pyrolysis of foam is followed by the oxidation of β -foam during the 1st stage with a lower peak temperature and limited oxygen supply, and the flashback in the 2nd stage is mainly dominated by char oxidation, which results in more heat releases and a higher peak temperature. The rapid temperature rise at the end of the 2nd stage, causing the maximum temperature in the whole smoldering process, is attributable to the oxidation of α -char (secondary char oxidation). [ABSTRACT FROM AUTHOR]

This study aims to find triggers for trauma, responses to trauma, and forms of trauma reconciliation experienced by the subject in the short story entitled “Ave Maria”. Therefore, this study bases its analysis on the short story “Ave Maria” using Cathy Caruth's point of view regarding the concept of trauma. This study found that the trauma experienced by the subject, Zulbahri, was a past event that brought the pain back because it was triggered by the presence of his younger brother, Syamsu, who interrupted the subject's safe space. In addition, the song “Ave Maria” in the short story also becomes a trauma site that reminds the subject of a traumatic event that creates crisis and vulnerability to the subject. The traumatic event that haunts the subjects responded with an unconscious display of shame and guilt. The subject carried out efforts to overcome trauma by staying away from the trauma-triggering site, distracting the mind with books, and sharing stories in a safe space. One last attempt to overcome the trauma chosen by the subject is to join the Jibakutai forces. This effort seems odd because it is prone to presenting another trauma in the form of war trauma to the subject.

Copyright of Alsun Beni-suef International Journal of Linguistics, Translation & Literature / Mağallaẗ Kulliyyaẗ Alsun Banī Swaīf Al-Dawliyyaẗ Li Luġawīyāt wa Al-Tarğamaẗ wa Al-Adab is the property of Beni Suef University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

“Awareness of difference in the Omani novel:A reading in the variety of content “ Difference is a cornerstone in the building of the societies; differences in culture, ideas,social,political and mainly artistic for it plays a considerable role in the development of the civilisation. Difference paves the way to innovation And the development of the narration discourse and its tools, which shows the the event and the reality in the framework of the imaginary and the real and the challenge of the reality. This is what makes me write about difference. In this context, the novel develops from depicting the reality to development of the character,which becomes the efficient element. Like the Arabic literature, the Omani novel has shown developments in style and language and goes beyond the awareness of difference. The novelist stands against the social and the political limitations and stands against all the taboos,which try to stop him from innovation and having another point of view. The novel,therefore is his framework to express his political, social and cultural views, a in the Omani society. In fact, the Omani novel opens its doors not only to its domestic areas,but to its international trend, participating in the Arabic and international literature. The question to be asked is how the Omani novel succeeds in developing its social, cultural and political issues. Another question to be asked is what are the social, cultural, historical and intellectual issues that the novel has dealt with and how it has reached the Arabic and international audiences. Some old modern surveys have participated in the development of the, Omani novel as far as the artistic and the thematic sides.We can mention as an example the Omani narrative discourse by Azzeza Thayi and another example “A study in the modern Omani narration “ by Ehsan Sadak Lawati and other different studies and some seminars about the Omani novel. This study has come to the conclusion that the Omani novelist wants to reach international reputation and this study has also come to the conclusion that the Omani novel has developed linguistically and artistically. The Omani novelist has emphasised the spirit of, d difference and it has the capacity to deal with social,intellectual and historical issues [ABSTRACT FROM AUTHOR]

Understanding boundary-layer flashback is critical to the design of safe and efficient gas turbines, especially as the addition of highly reactive hydrogen to these devices becomes a prevailing trend for reduction of carbon dioxide emissions. In this work, the boundary-layer flashback of lean hydrogen-air mixtures is studied using large-eddy simulations based on a generic turbulent swirl burner previously investigated experimentally. Simulations at increasing equivalence ratios are used to identify the flashback limits, showing reasonable qualitative agreement with experimental measurements. Flame dynamics during flashback are compared to previous experimental studies, indicating that important physics are captured in the simulations even if the exact flashback limits are not. In particular, a change in the swirl vane angle is shown to dramatically change the flame dynamics, with flame propagation occurring in the direction of swirl at high angles and against the direction of swirl at low angles, consistent with experimental observations. The near-wall nonreacting mean velocity field is shown to be controlled by a temporally stationary flow instability, which is directly responsible for the counterswirl flame flashback exhibited at low swirl angles. Finally, the interaction of local axial flow velocity and flame propagation speed of the leading flame point is investigated with varying swirl angles both before and after the onset of flashback, elucidating the differences in flame dynamics in all four of these cases. In particular, the importance of local flame extinction on flashback limits is emphasized. [ABSTRACT FROM AUTHOR]

This paper investigates the possibility of autoignition as a flashback initiation mechanism in laminar premixed burners powered by an increasing content of hydrogen in the fuel blend. A specific experimental setup provides an optical access inside a generic burner reproducing the main features of domestic boilers. This window is used to gather high-speed intensified images during transition to flashback. Zooms into the location of flashback initiation provide clear evidence for the existence of two distinct regimes. In the first one, flashback is initiated by a flame stabilized above the burner that is able to propagate upstream through one of the burner holes. In the second regime, flashback is initiated by autoignition of the fresh gases inside the burner, as they flow along the hot metallic internal wall. These observations are corroborated over a large range of equivalence ratio and hydrogen content. They demonstrate the dependence of the initiation regime on the burner wall temperature and highlight the role of the crossover temperature of hydrogen-enriched mixtures in triggering autoignition. An autoignition Damkohler number Da i that compares a residence time of gases along the hot wall and the autoignition delay time is defined. The ratio Da i is found to be more than an order of magnitude higher for autoignition-induced cases compared to the cases initiated by a flame propagating upstream, further supporting the existence of two distinct mechanisms leading to flashback. These results carry substantial implications on the design process of H 2 -enriched laminar premixed burners. • Flashback in a premixed laminar burner is investigated with a transparent setup when hydrogen is substituted to methane. • The burner temperature controls the mechanism by which flashback is initiated when the hydrogen content increases. • Flashback propagates upstream through a burner hole when burner walls are moderately hot. • Autoignition of the combustible mixture impinging the inner walls takes over when the burner walls are hot enough. • A Damkohler number enables to identify which regime is taking place. [ABSTRACT FROM AUTHOR]

This study delves into the effects of altering the geometrical dimensions of a Self-Aspirated Porous Radiant Burner (SA-PRB) of 5 kW capacity, focusing primarily on the Mixing Tube (MT) and orifice, and their influence on air entrainment and flame stability. To simulate flow and combustion, the study utilized the RNG k-ɛ and Eddy Dissipation Models, respectively, employing a four-step reaction scheme for LPG combustion. Examining various combinations of MT dimensions, orifice sizes, and their positions within the MT, the study scrutinized flame length, heat distribution uniformity, and flashback. Both numerical simulations and experimental observations corroborated the findings, highlighting the significant impact of orifice and MT dimensions on Primary Air Entrainment (PA). Optimal geometrical configurations are identified as crucial for achieving the combustion stability in PRBs. Configurations resulting in unstable PRB operation such as non-uniform temperature distribution, flashback etc., have been discussed. Stable operation is achieved in the partially submerged combustion mode with an optimized setup featuring a 0.3 mm OD orifice positioned 30 mm from the datum, coupled with a 29 mm MTD. This configuration yields a PA of 79 % and a maximum temperature of 979 °C, and demonstrated efficacy of the proposed design in enhancing PRB performance. [Display omitted] • Numerical study of dependency of Primary Air Entrainment (PA) on burner geometry. • Impact of PA on the flame stability of a Porous Radiant Burner (PRB) was studied. • Optimized positions and diameters of orifice and mixing tube (MT) were obtained. • PA of 79 % yielded stable partially submerged combustion. • Optimized PRB at orifice offset of 30 mm, diameter 0.3 mm and MT diameter 29 mm. [ABSTRACT FROM AUTHOR]

Background: The psychedelic 5-MeO-DMT has shown clinical potential due to its short duration and ability to induce mystical experiences. However, a phenomenon known as "reactivations" (similar to "flashbacks") is a poorly understood and frequently reported phenomenon which appears associated with 5-MeO-DMT use and warranted further investigation. Aims: This study examined whether differences in age, gender, education, lifetime use, use location, and preparation strategies predict reactivations (primary outcome). Additionally, we explored how reactivations were perceived by survey respondents and whether demographic data predicted emotional valence (secondary outcome) of reported reactivations. Materials and methods: This study used secondary quantitative data from a survey assessing epidemiological and behavioral associations of 5-MeO-DMT use in non-clinical settings (N = 513). Descriptive statistics, chi-square tests, t-tests, and logistic regressions were utilized to explore aims. Results: Being female, older at the time of first 5-MeO-DMT dose, having higher educational attainment, and dosing in a structured group setting were associated with increased odds of reporting a reactivation event. Higher mystical experience scores, greater personal wellbeing and having had a non-dual awareness experience that was not substance-induced were associated with higher likelihood of reporting a neutral or positive emotional valence of a reactivation event. Conclusion: These findings suggest that reactivation phenomena, in this particular sample may most often represent a neutral or positive byproduct of the acute 5-MeO-DMT experience. More information is needed to best identify individuals most likely to experience a reactivation as a negative event to prevent such potential challenging outcomes. [ABSTRACT FROM AUTHOR]

Regreso al futuro relata las aventuras de un adolescente y un científico que crea una máquina para viajar en el tiempo instalada en un DeLorean. Pero los frecuentes saltos no afectan a la linealidad narrativa: el relato se instala en el presente. El viaje temporal destila el uso convencional que el cine clásico ha hecho del flashback: el de una parada controlada que permite esclarecer la historia. Por contra, observamos en numerosas ficciones postclásicas que los saltos temporales no aparecen tanto para explicar la historia sino para confundirla. Continuaremos esta hipótesis a propósito de Perdidos y La piel que habito.