Momentary Increase Research Articles

Experimental and numerical study on explosion behavior of hydrogen-air mixture in an obstructed closed chamber

The flame evolution, flame front speed and pressure dynamics are investigated through experimental and simulation analysis. The effects of the obstacle on velocity vector field and vorticity field are analyzed. The results indicate that a rise in blockage ratio causes a rapid rise in flame front speed. The turbulent combustion, flame backflow, and overpressure are significantly enhanced as obstacle distance and blockage ratio increase. The jet flame results in a surge in flame front speed, and a momentary increase in pressure rise. The flame-vortex interaction causes strong turbulent combustion and a rapid overpressure increase. The overpressure displays regular periodic fluctuations and high-frequency oscillations with high amplitudes, which can be attributed to the dynamic and impulsive responses. The vortex results in the formation of a curled flame with high localized vorticity. The backflow flame, exhibiting an extremely high vorticity magnitude, is induced by the overall pressure gradient and flow field recirculation.

Response of a novel denitrifying phosphorus removal (AAO-BCO) system to sinusoidal flow perturbation of municipal sewage: Adaptability, tolerance and improvement

To date, studies on the effect of sewage disturbances on treatment facilities were based on fixed-length flow variations, which are incapable of imitating the actual dynamic flow characteristics of municipal sewage. Here, an innovative dynamic influent disturbance control system is established in this study and applied in a novel denitrifying phosphorus removal (anaerobic anoxic oxic-biological contact oxidation, AAO-BCO) system to simulate seasonal and diurnal sewage fluctuations in laboratory-scale experiments. The results showed that, under sinusoidal influent flow perturbation, the effluent pollutant content followed a relatively gentle sinusoidal trend and did not always result in desired level of pollutant removal. The ability of the system to cope with sinusoidal flow variations was susceptible to the amplitude of diurnal sewage fluctuation, while stronger tolerance capacity was observed to seasonal and momentary increase in wastewater flowrate. There was also a discrepancy in the system buffering capacity towards various pollutants removal (COD > TIN > PO43−), which may be attributed to wide fluctuations in PO43−/NO3− and different decrease in metabolic activity of denitrifying phosphorus removal (DPR) sludge caused by extreme hydraulic retention times. To improve the robustness and stability of the DPR system, a regulating strategy was proposed to alleviate the biomass reduction and uncoordinated PO43−/NO3−.

Fertilization, pruning and controlled fires on the growth of Feijoa sellowiana (O. Berg) O. Berg.

Feijoa sellowiana (O.Berg) O. Berg is an ornamental and food plant, as well as an important species for ecological restoration and landscaping that still requires much research before consolidating it in the tropical market. To understand if the implementation of techniques focusing on improving fruit production at its wild condition would affect the species’ development, we planted 216 saplings of various mother trees in an incomplete factorial block design applied in nine treatments. We tested formative aerial pruning (drastic intensity), fertilization (chemical and organic), and the effect of controlled fires prior to planting. We evaluated biomass alterations by systematically measuring the third sapling of each treatment, quantifying fresh and dry matter in two periods. We also measured changes in height (H), root collar diameter (RCD), and the H/RCD ratio. We carried out nine measurements during 27 months and used linear mixed-effects models to consolidate the long-term evaluation. Our results indicate a positive effect from the organic fertilization on the plants’ height, a momentary increase in RCD caused by programmed fires, and an increase in the H/RCD ratio due to formative aerial pruning (increasing resistance). Fertilization did not accelerate the increase in RCD and had no effect on the H/RCD ratio.

Roles of Calcium Signaling in Gene Expression and Photosynthetic Acclimatization of Solanum lycopersicum Micro-Tom (MT) after Mechanical Damage.

A momentary increase in cytoplasmic Ca2+ generates an oscillation responsible for the activation of proteins, such as calmodulin and kinases, which interact with reactive oxygen species (ROS) for the transmission of a stress signal. This study investigated the influence of variations in calcium concentrations on plant defense signaling and photosynthetic acclimatization after mechanical damage. Solanum lycopersicum Micro-Tom was grown with 0, 2 and 4 mM Ca2+, with and without mechanical damage. The expression of stress genes was evaluated, along with levels of antioxidant enzymes, hydrogen peroxide, lipid peroxidation, histochemistry, photosynthesis and dry mass of organs. The ROS production generated by mechanical damage was further enhanced by calcium-free conditions due to the inactivation of the oxygen evolution complex, contributing to an increase in reactive species. The results indicated that ROS affected mechanical damage signaling because calcium-free plants exhibited high levels of H2O2 and enhanced expression of kinase and RBOH1 genes, necessary conditions for an efficient response to stress. We conclude that the plants without calcium supply recognized mechanical damage but did not survive. The highest expression of the RBOH1 gene and the accumulation of H2O2 in these plants signaled cell death. Plants grown in the presence of calcium showed higher expression of SlCaM2 and control of H2O2 concentration, thus overcoming the stress caused by mechanical damage, with photosynthetic acclimatization and without damage to dry mass production.

Can you hear me now? Momentary increase in smartphone usage enhances neural processing of task-irrelevant sound tones

According to popular belief when engaged on the smartphone surrounding information is ignored. However, emerging ideas based on laboratory-designed tasks suggest that the processing of task-irrelevant (distractor) information is enhanced when cognitive load is high as anticipated during intense periods of smartphone usage. Here we address the neural processing of task-irrelevant auditory tones while interacting with the smartphone touchscreen. We analyzed neural activity (EEG) while people (N = 24) were seated in public spaces and used their smartphones for ∼1.5 h. During this period, the number of touchscreen interactions spontaneously varied from one moment to another. The central and frontal theta-band (4–8 Hz) oscillations, an index of cognitive load, increased proportionally to the number of interactions. Moreover, an index of excitation:inhibition balance derived from the aperiodic signal components increased with the interactions. The auditory tones resulted in prominent evoked potentials with peaks at ∼50 ms, ∼100 ms, and ∼200 ms, reflecting the different cortical information processing stages. Of these, the ∼100 ms component was specifically related to the number of interactions such that the higher the number of interactions, the larger the neural signal amplitudes. Contrary to the popular notions but in keeping with emerging ideas on cognitive load, auditory information processing is enhanced with increased smartphone usage. In daily life, neural processing of the surroundings is partly shaped by the immediate cognitive demands imposed by the smartphone.

The Relation of Mood and Sexual Desire: An Experience Sampling Perspective on the Dual Control Model

We investigated the effect of fluctuations in negative and positive affect on momentary sexual motivation in a sample of women and men in a steady relationship (n = 133). Sexual motivation was regarded as the aggregate of sexual desire, subjective sexual arousal and openness to sexual contact. Experience sampling methodology was used to collect up to 70 measurements per participant over a period of seven consecutive days of sexual motivation, and negative and positive affect. Using multilevel analysis, we investigated cross-level interactions between affect and trait measures as specified in the dual control model (DCM). This model postulates sexually excitatory and inhibitory mechanisms as relatively independent systems that together can explain individual differences in sexual motivation and behavior. Results implicated that any intensification of feelings, positive or negative, was associated with a momentary increase in sexual motivation for participants more prone to sexual excitation. In the lagged analysis, higher preceding negative affect, measured 1–2 h earlier, forecasted an increase in current sexual motivation for participants more prone to sexual excitation. The lagged analysis included the autoregressive effect or inertia of sexual motivation. Inertia reflects the extent to which sexual motivation lingers and persists at similar levels. Our findings showed that sexual motivation levels persisted less in individuals with higher sexual inhibition proneness due to threat of performance failure. This study demonstrated how experience sampling methodology can be used to extend research on associations between mood and sexual motivation and implicates that DCM factors moderate these associations.

Stability Tests on Anion Exchange Membrane Water Electrolyzer under On-Off Cycling with Continuous Solution Feeding

In this study, the stability of an anion exchange membrane water electrolyzer (AEMWE) cell was evaluated in an on-off cycling operation with respect to an applied electric bias, i.e., a current density of 500 mA cm−2, and an open circuit. The ohmic and polarization resistances of the system were monitored during operation (~800 h) using electrochemical impedance spectra. Specific consideration was given to the ohmic resistance of the cell, especially that of the membrane under on-off cycling conditions, by consistently feeding the cell with KOH solution. Owing to an excess feed solution, a momentary increase in the polarization resistance was observed immediately after the open-circuit. The excess feed solution was mostly recovered by subjecting the cell to the applied electric bias. Stability tests on the AEMWE cell under on-off cycling with continuous feeding even under an open circuit can guarantee long-term stability by avoiding an irreversible increase in ohmic and polarization resistances.

The contribution of latent factors of executive functioning to mind wandering: an experience sampling study

Accumulating evidence suggests that individuals with greater executive resources spend less time mind wandering. Independent strands of research further suggest that this association depends on concentration and a guilty-dysphoric daydreaming style. However, it remains unclear whether this association is specific to particular features of executive functioning or certain operationalizations of mind wandering, including task-unrelated thoughts (TUTs, comprising external distractions and mind wandering) and stimulus-independent and task-unrelated thoughts (SITUTs, comprising mind wandering only). This study sought to clarify these associations by using confirmatory factor analysis to compute latent scores for distinct executive functions based on nine cognitive tasks and relating them to experience sampling reports of mind wandering. We expected that individuals with greater executive control (specifically updating) would show a stronger reduction in SITUTs as momentary concentration and guilty-dysphoric style increase. A bifactor model of the cognitive battery indicated a general factor (common executive functioning) and ancillary factors (updating and shifting). A significant interaction between updating and concentration on mind wandering was observed with mind wandering defined as TUTs, but not as SITUTs (N = 187). A post hoc analysis clarified this discrepancy by showing that as concentration increases, both external distractions and mind wandering decrease more strongly among people with greater updating. Moreover, common executive functioning predicted a more negative slope of guilty-dysphoric style on SITUTs, whereas updating and shifting predicted more positive slopes. The opposite slopes of these executive functions on daily life mind wandering may reflect a stability-flexibility trade-off between goal maintenance and goal replacement abilities.

Insight into flickering/shedding in buoyant droplet-diffusion flame during interaction with vortex

The interaction of incident vortex with buoyant diffusion flame of a pendant fuel droplet (n-dodecane) is investigated in the present study. The flame stretching/shedding events occur depending on vortex strengths, which are characterized using vortex Reynolds number (Rev). Different flame response regimes have been identified for different vortex strengths. The velocity scale associated with the vortices is higher when compared to natural convection velocity leading to forward extinction, followed by flame lift-off. The flame lift-off increases with Rev, and partial extinction occurs at very high Rev. In all the cases, the flame oscillates/sheds during the vortex interaction, which causes a momentary increase in the flame heat release rate. As the vortex moves past the flame, the oscillations dampen gradually, and the flame regains the natural buoyant behavior. The high-velocity scales imposed during vortex interaction make the flow momentum-dominant, resulting in a low Richardson number (Ri). Since, the flickering frequency scaling valid for Ri>>1 is not obeyed, a new scaling has been proposed to incorporate the vortex momentum effect by using vortex circulation instead of gravity. Only a portion of the incident vortex circulation contributes to the shedding as some of it is lost to forward extinction and lift-off events. Thus, the reduced vortex velocity scale is used to estimate the critical circulation. The flame shedding height calculated using new scaling in the critical circulation equation agrees with experimental observations.

The Aftermath of IrMaria in the U.S. Virgin Islands: Temporal Patterns of Looting, Burglaries, and Community Solidarity

This study investigates the aftermath of Hurricanes Irma and Maria (IrMaria) in the U.S. Virgin Islands and the dichotomy between media reports depicting mass looting and chaos with statements by public officials disputing these claims. Perceptions on post-hurricane criminality can influence sheltering and evacuation behavior as well as frame public policy. The authors review the post-disaster collective behavior literature and implement a mixed-methods approach to examine the veracity of these looting claims. Post-disaster interviews with impacted households, business owners, and public servants reveal a pro-social environment with strong community solidarity in the immediate aftermath of IrMaria. Sheltering behavior was not influenced by fears of looting, but was influenced by previous hurricane false alarms. Regression of available FBI-UCR data shows the rate of burglary has declined across the islands since 2010. An aggregate-level report by the U.S. Virgin Islands Police Department shows a decline in all crimes throughout the US territory compared to the fiscal year before IrMaria, but a four percent increase in burglary incidents. The comparable increase in incidents occurred within four months of IrMaria's landfall, followed by a precipitous decrease in incidents. This finding aligns with theoretical calls to consider temporal phases and patterns of post-disaster crime. Considering the delayed federal response and the decrease in all other crimes for the fiscal year, the authors attribute the momentary increase in burglary incidents as a misnomer and are likely survival appropriating acts that decreased with burgeoning humanitarian assistance. This study recommends disaster public policy and recovery efforts prioritize the unmet needs of hurricane survivors and greater scrutiny of the constraints of US colonialism that impede disaster resilience. Additionally, the paper highlights other concerns raised by participants during fieldwork interviews and emphasizes the necessity and value of ethical post-disaster qualitative research.

The influence of gas temperature on ozone generation and decomposition in ozone generator. How is ozone decomposed?

The ozone synthesis and decomposition processes in a heated ozone generator (10–70 °C) in a pulse discharge was investigated. Concentrated ozone (up to 200 g Nm−3) was also decomposed at temperatures of 10–90 °C without discharges for comparison. It was found that for residence times up to approx. 4 s, the gas temperature in the gap has no significant effect on the ozone concentration drop. However, the appearance of electrical discharges in the gap causes that even at low temperatures and at very low powers, ozone decomposition is intensive. It has been shown that ozone decomposition is caused by a momentary increase in gas temperature (energy) within the microdischarge channels, and not by high gas temperature in the entire discharge gap. Ozone decomposition occurs mainly in microdischarge channels. The increase in gas temperature adversely affects the ozone concentration achieved, as it hinders the removal of heat from the microdischarge channels.

Transient photovoltage overshoot in multi-cation perovskite solar cells: An interplay between interfacial ionic layer and photoinduced electric field

The dynamics of correlated ionic-electronic components often get reflected in the measured photovoltage of a hybrid perovskite solar cell. This communication describes a unique overshoot voltage phenomenon that appears soon the light is turned off during the large signal photovoltage transient measurements at low (≤250K) temperature regime. The occurrence of the overshoot voltage largely depends on fluence, temperature and can be perturbed with device preconditioning. We observe that the phenomenon occurs only in TiO2 based devices but never if the electron transport layer is SnO2 indicating that the interface plays a major role. Our investigations reveal a strong correlation between the ionic movement and the transitory photogenerated electric field that are responsible for the momentary increase in the measured potential.

Within-day rhythms of pain and cognitive function in people with and without fibromyalgia: synchronous or syncopated?

Cognitive dysfunction is a common fibromyalgia (FM) symptom and can impact on the daily lives of those affected. We investigated whether within-day pain intensity ratings were associated with contemporaneous objective and subjective measures of cognitive function and whether within-day increases in pain intensity preceded increases in cognitive dysfunction or vice versa. Inclusion of a non-FM group allowed us to examine whether effects were specific to FM. Fifty people with FM and 50 non-FM controls provided 7 days of data. Cognitive tests (processing speed and working memory) and ecological momentary assessments (pain intensity and self-reported cognitive functioning) were conducted ×5/day. Three-level multilevel models examined contemporaneous and within-day 1-lag pain intensity-cognitive functioning associations. Interaction terms assessed possible moderating effects of FM status. Momentary increase in pain was associated with increased self-reported cognitive dysfunction, more strongly so for those with FM (B = 0.27, 95% confidence interval 0.22-0.32; non-FM B = 0.17, 95% confidence interval 0.10-0.23). For the FM group, higher pain was associated with longer processing speed; for the non-FM group, higher pain was associated with shorter processing speed. Pain increase did not precede change in subjective or objective cognitive function in the FM group, but reduction in working memory preceded increase in pain intensity. This finding warrants further research attention and, if replicated, could hold prognostic and/or therapeutic potential.

A crystal plasticity model with an atomistically informed description of grain boundary sliding for improved predictions of deformation fields

Crystal plasticity (CP) is a powerful meso-scale technique for deformation modeling in polycrystalline materials. Crystal plasticity models typically do not include an explicit description of grain boundary (GB) sliding, which could lead to inaccurate predictions of strain distributions, especially in the vicinity of GBs. In the present study, a CP model is developed that includes GB sliding as an additional deformation mechanism and models the interaction between slip and GB sliding. Atomistic simulations are used to formulate the constitutive model for GB sliding and its interaction with incident slip. The deformation fields and structure of the GBs are obtained directly from experimental characterization and are faithfully reproduced as bicrystal systems for molecular dynamics simulations. The GBs are modeled as random-type (non-coincidence, asymmetrical) boundaries as observed from experimental data. The underlying atomistic-scale mechanism for pure sliding of random GBs was found to be analogous to fluid-flow. The interaction between incident slip and a sliding GB caused local increases in stress concentration, which further led to a momentary increase in the local sliding rate. The displacement profiles at the sliding GBs computed from the CP model with sliding accommodation are 38% more accurate than the baseline CP model as quantified by the mean squared error between the simulations and experiment. These results help improve the sophistication and accuracy of deformation modeling by including physics-based descriptions for GB sliding and its interaction with slip, eventually leading to more reliable predictions of micromechanical quantities.

Pass-Through of Crude-oil Price Shocks to Consumer Prices in Nigeria: Pre and Post 2008 Global Financial Crisis

This study investigates the responses of consumer price index (CPI) to crude oil price shocks in the pre- and post-2008 global financial crisis. The study used the Structural Vector Autoregressive model to analyse monthly data from 2000M01 to 2019M12. The impulse response analysis showed that for pre and post-crisis periods, oil price shocks have a positive impact on CPI. This impact was an insignificant direct momentary increase in pre-crisis CPI before dissipating. Conversely, the impact on post crisis CPI response tends to be stable and long-lasting starting from the third month. The confidence bands for the post crisis CPI are large, indicating the long-lasting positive response in the CPI pose no significant threat to price stability in the long run horizon. In conclusion, CPI response varies in terms of intensity for pre and post crisis periods. In terms of level of significance, the effect of the shocks on CPI is transient and insignificant in both periods. The post crisis oil price shock is not a significant channel that created price instability in Nigeria after the crisis and this study recommend partial deregulation of energy price should be maintained. Establishing oil price –inflation pass-through, external shocks like financial crisis should be accounted for.

Ligand sensing enhances bacterial flagellar motor output via stator recruitment.

It is well known that flagellated bacteria, such as Escherichia coli, sense chemicals in their environment by a chemoreceptor and relay the signals via a well-characterized signaling pathway to the flagellar motor. It is widely accepted that the signals change the rotation bias of the motor without influencing the motor speed. Here, we present results to the contrary and show that the bacteria is also capable of modulating motor speed on merely sensing a ligand. Step changes in concentration of non-metabolizable ligand cause temporary recruitment of stator units leading to a momentary increase in motor speeds. For metabolizable ligand, the combined effect of sensing and metabolism leads to higher motor speeds for longer durations. Experiments performed with mutant strains delineate the role of metabolism and sensing in the modulation of motor speed and show how speed changes along with changes in bias can significantly enhance response to changes in its environment.

Salivary beta-endorphin in nonsuicidal self-injury: an ambulatory assessment study

Nonsuicidal self-injury (NSSI) is a prevalent and impairing behavior, affecting individuals with and without additional psychopathology. To shed further light on biological processes that precede and result from NSSI acts, we built on previous cross-sectional evidence suggesting that the endogenous opioid system, and especially β-endorphin, is involved in the psychopathology of NSSI. This is the first study assessing salivary β-endorphin in daily life in the context of NSSI acts. Fifty-one female adults with repetitive NSSI participated over a period of 15 days in an ambulatory assessment study. Salivary β-endorphin was assessed before and after engagement in NSSI, during high urge for NSSI, and on a non-NSSI day. Furthermore, NSSI specific variables such as pain ratings, as well as method, severity, and function of NSSI were assessed. We found that β-endorphin levels immediately before an NSSI act were significantly lower than directly after NSSI. However, there was no difference between β-endorphin during high urge for NSSI and post NSSI measures. We found a positive association between severity of the self-inflicted injury and β-endorphin levels, but no significant association between β-endorphin levels and subjectively experienced pain. The results of the present study indicate that it is possible to assess salivary β-endorphin in daily life in the context of NSSI. Furthermore, our results provide a first indication that NSSI acts could be associated with a momentary increase of β-endorphin, and this might reinforce NSSI engagement. More research is needed to replicate and extend our findings on peripheral β-endorphin in daily life.

Canopy recovery four years after logging: a management study in a southern brazilian secondary forest

ABSTRACT Background: Understanding forest dynamics after logging is essential to define forest management cycles and intensities. In secondary forest, especially in the Atlantic Forest Domain, these studies are still scarce. Monitoring of the canopy structure after tree harvesting can be performed by hemispherical photographs, where canopy opening is commonly analyzed. This study evaluated changes in canopy opening four years after tree harvesting in a secondary Atlantic Rainforest in southern Brazil. We used hemispherical photographs to determine the Canopy Openness (CO), Leaf Area Index (LAI), and Diffuse Fraction of Photosynthetically Active Absorbed Radiation (FAPARdif) in eleven permanent plots. Results: We found that harvesting resulted in a momentary increase in canopy opening and light availability in the understory. Four years after harvesting, CO, LAI and FAPARdif recovered or even exceeded the original values of the forest. We observed a significant correlation between CO and number of trees harvested with DBH > 30 cm. Weak correlations were found between these canopy related variables and the logging intensity. Conclusion: In conclusion, we recognized that changes of CO, LAI and FAPARdif after timber harvesting presented short duration. This indicates that the applied logging intensities, 21.8 to 51.1% of the total basal area, did not exceed the resilience of the forest canopy and it’s recovering four years later. However, additional studies should be carried out to observe vegetation dynamics, such as species composition, vertical structure, productivity and community stability, in order to improve management schemes of secondary stands in the Atlantic Forest.

Knowledge of the Covid-19 Virus, From Diagnosis to Prevention and Treatment: A Narrative Review

Introduction: Coronavirus or Covid-19 is a type of acute respiratory syndrome caused by a virus from the corona family of viruses that have affected all countries in the world in a short period. Familiarity and introduction of Covid-19 virus is very important due to the prevalence and high mortality rate of this disease, as well as the possibility of recurrence of Covid-19, especially in autumn, and the lack of vaccines or specific treatment. Objective: The aim of this study was "Introduction to Covid-19 virus in terms of diagnosis, prevention and treatment" Material and Methods: In this study, researchers did a survey of search engine such as Google Scholar, Google, PubMed databases, Science Direct and CDC and WHO sites in 2019 and 2020 , related to the purpose of the study (in "Persian" and "English"). Results: In the present study, diagnosis, treatment programs, prevention and control of disease was done using updated data on Covid-19 virus, epidemiology of disease, structure, and source of the virus, disease symptoms and routes of transmission. , . The diagnosis of this virus, besides its clinical signs, relies on laboratory and radiological findings. Any specific drug treatment will not be introduced for Covid-19 until June 30, 2020, so the best way in the current situation is to prevent the disease. Discussion and Conclusion: Due to the momentary increase in patients with Covid-19 and its high mortality, lack of vaccines and definitive drug treatment, it is recommended that people apply the correct health principles, and observe the social sdistances. To prevent and manage the recurrence of Covid-19 in the fall, it is an undeniable necessity to develop and implement comprehensive and infrastructural programs immediately. Is an.

COUPLED ELECTROMAGNETIC-THERMAL SIMULATION OF A POWER TRANSFORMER BY 3D FEM

Power transformers are the most common equipment in an electric power system, which has been manufactured in the last decade. However, overheating can damage them, considerably reducing their operation lives, which may cause economic losses to the power utilities. The motivation of this paper is to investigate the time and power overload limits that a power transformer can be subjected to and how it will impact its temperature. Investments in the grid can be delayed if a transformer can support some overload during some momentary load demand increase. In this context, this paper presents a study of a 30/40MVA power transformer by 3D finite element method (FEM) for coupled thermal-electromagnetic simulations to investigate its thermal behaviour when it is submitted to its nominal load at a steady-state operation and a variable load during a period of one day. The simulations were performed with the commercial software packages Flux 3D and AcuSolve, for electromagnetic and thermal modelling, respectively. The modelled equipment was based on a power transformer installed in the Light Serviços de Eletricidade S.A, the utility that supplies electrical energy to the city of Rio de Janeiro, in Brazil. Since the literature doesn’t present many works simulating coupled thermal-electromagnetic power transformers in 3D-FEM, this paper has the goal to bring new contributions to this field. Three study cases were modelled, and some simplifications in transformer’s geometry were made in some of them to reduce the computation time usually required for such a simulation. The obtained results are presented and compared with the measured values for the temperature in the hot spot of the transformer and in the top of the oil, to investigate the impact of these simplifications in the calculated results.