The Impact of the Graphite Nanofiber Structure on the Behavior of Supported Nickel

1997 ◽  
Vol 497 ◽  
Author(s):  
C. Park ◽  
R. T. K. Baker
Keyword(s):  
Metal Particles ◽  
Unsaturated Aldehyde ◽  
Catalytic Behavior ◽  
Support Materials ◽  
Crotyl Alcohol ◽  
Nickel Particles ◽  
Different Types ◽  
Hydrogenation Reactions ◽  
The Impact ◽  
Hydrogenation Of Ethylene

ABSTRACTIn the current investigation we have used the hydrogenation of ethylene and crotonaldehyde as probe reactions in an attempt to follow any changes in catalytic behavior induced by supporting nickel on different types of graphite nanofiber support materials. The hydrogenation of the α,β-unsaturated aldehyde to the desired product, crotyl alcohol, is a particularly difficult task since there is a strong tendency to hydrogenate both the C=C and C=O in the reactant molecule. This study is designed to compare the catalytic behavior of the metal particles when dispersed on three types of nanofibers, where the orientation of the graphite platelets within the structures is significantly different in each case. The metal crystallites are located in such a manner that the majority of particles are in direct contact with graphite edge regions. For comparison purposes, the same set of hydrogenation reactions were carried out under similar conditions over γ-Al2O3 supported nickel particles.

Use of Graphite Nanofibers as a Novel Catalyst Support Medium for Hydrogenation Reactions

1996 ◽  
Vol 454 ◽  
Author(s):  
C. Park ◽  
N. M. Rodriguez ◽  
R. T. K. Baker
Keyword(s):  
Carbon Nanofibers ◽  
Carbon Nanofiber ◽  
Catalyst Support ◽  
Catalytic Behavior ◽  
Graphite Nanofibers ◽  
Nickel Particles ◽  
Support Medium ◽  
Different Types ◽  
Hydrogenation Reactions ◽  
Novel Catalyst

ABSTRACTIn this investigation we elected to use the hydrogenation of 1-butene as probe reactions in an attempt to monitor any possible changes in catalytic behavior resulting from supporting 5 wt.% nickel on different types of carbon nanofibers compared to the performance of the same metal loading on more traditional carriers, including γ-Al2O3 and active carbon. In all cases the carbon nanofiber supported nickel particles are found to exhibit superior activity and significant changes in selectivity to that found from the same metal supported on traditional carriers.

scholarly journals Numerical Simulation of Melting Kinetics of Metal Particles during Tapping with Argon-Bottom Stirring

Crystals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 901
Author(s):  
Kinnor Chattopadhyay ◽  
Rodolfo Morales-Davila ◽  
Alfonso Nájera-Bastida ◽  
Jafeth Rodríguez-Ávila ◽  
Carlos Rodrigo Muñiz-Valdés
Keyword(s):  
Room Temperature ◽  
Melting Furnace ◽  
Melting Process ◽  
Melting Rate ◽  
Metal Particles ◽  
Melting Kinetics ◽  
Nickel Particles ◽  
Filling Time ◽  
The Impact ◽  
Kinetics Of

Molten steel is alloyed during tapping from the melting furnace to the argon-bottom stirred ladle. The metallic additions thrown to the ladle during the ladle filling time are at room temperature. The melting rates or kinetics of sinking-metals, like nickel, are simulated through a multiphase Euler–Lagrangian mathematical model during this operation. The melting rate of a metallic particle depends on its trajectory within regions of the melt with high or low turbulence levels, delaying or speeding up their melting process. At low steel levels in the ladle, the melting rates are higher on the opposite side of the plume zone induced by the bottom gas stirring. This effect is due to its deviation after the impact of the impinging jet on the ladle bottom. The higher melting kinetics are located on both sides at high steel levels due to the more extensive recirculation flows formed in taller baths. Making the additions above the eye of the argon plume spout increases the melting rate of nickel particles. The increase of the superheat makes the heat flux more significant from the melt to the particle, increasing its melting rate. At higher superheats, the melting kinetics become less dependent on the fluid dynamics of the melt.

Quota Women Are Threatening to Men

2017 ◽  
Vol 76 (3) ◽  
pp. 107-116 ◽  
Author(s):  
Klea Faniko ◽  
Till Burckhardt ◽  
Oriane Sarrasin ◽  
Fabio Lorenzi-Cioldi ◽  
Siri Øyslebø Sørensen ◽  
...  
Keyword(s):  
Decision Making ◽  
Organizational Performance ◽  
Gender Stereotypes ◽  
Perceived Threat ◽  
Preferential Treatment ◽  
Public Sector Employees ◽  
Different Types ◽  
Low Levels ◽  
Women In Decision Making ◽  
The Impact

Abstract. Two studies carried out among Albanian public-sector employees examined the impact of different types of affirmative action policies (AAPs) on (counter)stereotypical perceptions of women in decision-making positions. Study 1 (N = 178) revealed that participants – especially women – perceived women in decision-making positions as more masculine (i.e., agentic) than feminine (i.e., communal). Study 2 (N = 239) showed that different types of AA had different effects on the attribution of gender stereotypes to AAP beneficiaries: Women benefiting from a quota policy were perceived as being more communal than agentic, while those benefiting from weak preferential treatment were perceived as being more agentic than communal. Furthermore, we examined how the belief that AAPs threaten men’s access to decision-making positions influenced the attribution of these traits to AAP beneficiaries. The results showed that men who reported high levels of perceived threat, as compared to men who reported low levels of perceived threat, attributed more communal than agentic traits to the beneficiaries of quotas. These findings suggest that AAPs may have created a backlash against its beneficiaries by emphasizing gender-stereotypical or counterstereotypical traits. Thus, the framing of AAPs, for instance, as a matter of enhancing organizational performance, in the process of policy making and implementation, may be a crucial tool to countering potential backlash.

Situational Breakdowns

2019 ◽  
Author(s):  
Anne Nassauer
Keyword(s):  
United States ◽  
Large Scale ◽  
Contextual Factors ◽  
The United States ◽  
Social Outcomes ◽  
Dynamic Processes ◽  
Collective Decisions ◽  
Different Types ◽  
The Impact

This book provides an account of how and why routine interactions break down and how such situational breakdowns lead to protest violence and other types of surprising social outcomes. It takes a close-up look at the dynamic processes of how situations unfold and compares their role to that of motivations, strategies, and other contextual factors. The book discusses factors that can draw us into violent situations and describes how and why we make uncommon individual and collective decisions. Covering different types of surprise outcomes from protest marches and uprisings turning violent to robbers failing to rob a store at gunpoint, it shows how unfolding situations can override our motivations and strategies and how emotions and culture, as well as rational thinking, still play a part in these events. The first chapters study protest violence in Germany and the United States from 1960 until 2010, taking a detailed look at what happens between the start of a protest and the eruption of violence or its peaceful conclusion. They compare the impact of such dynamics to the role of police strategies and culture, protesters’ claims and violent motivations, the black bloc and agents provocateurs. The analysis shows how violence is triggered, what determines its intensity, and which measures can avoid its outbreak. The book explores whether we find similar situational patterns leading to surprising outcomes in other types of small- and large-scale events: uprisings turning violent, such as Ferguson in 2014 and Baltimore in 2015, and failed armed store robberies.

scholarly journals A global analysis of the impact of COVID-19 stay-at-home restrictions on crime

2021 ◽  
Author(s):  
Amy E. Nivette ◽  
Renee Zahnow ◽  
Raul Aguilar ◽  
Andri Ahven ◽  
Shai Amram ◽  
...  
Keyword(s):  
Public Space ◽  
Global Analysis ◽  
Sudden Change ◽  
Interrupted Time Series ◽  
Urban Crime ◽  
Substantial Variation ◽  
Different Types ◽  
Time Series Analyses ◽  
The Impact ◽  
At Home

AbstractThe stay-at-home restrictions to control the spread of COVID-19 led to unparalleled sudden change in daily life, but it is unclear how they affected urban crime globally. We collected data on daily counts of crime in 27 cities across 23 countries in the Americas, Europe, the Middle East and Asia. We conducted interrupted time series analyses to assess the impact of stay-at-home restrictions on different types of crime in each city. Our findings show that the stay-at-home policies were associated with a considerable drop in urban crime, but with substantial variation across cities and types of crime. Meta-regression results showed that more stringent restrictions over movement in public space were predictive of larger declines in crime.

Comprehensive Effects of Short-Term Rental Platforms Across Hotel Types in U.S. and International Destinations

2021 ◽  
pp. 193896552110335
Author(s):  
John W. O’Neill ◽  
Jihwan Yeon
Keyword(s):  
Service Providers ◽  
Comprehensive Analysis ◽  
Competitive Market ◽  
Substitution Effects ◽  
Short Term ◽  
Hotel Performance ◽  
The World ◽  
Different Types ◽  
Location Type ◽  
The Impact

In recent years, short-term rental platforms in the lodging sector, including Airbnb, VRBO, and HomeAway, have received extensive attention and emerged as potentially alternative suppliers of services traditionally provided by established commercial accommodation providers, that is, hotels. Short-term rentals have dramatically increased the available supply of rooms for visitors to multiple international destinations, potentially siphoning demand away from hotels to short-term rental businesses. In a competitive market, an increase in supply with constant demand would negatively influence incumbent service providers. In this article, we examine the substitution effects of short-term rental supply on hotel performance in different cities around the world. Specifically, we comprehensively investigate the substitution effects of short-term rental supply on hotel performance based on hotel class, location type, and region. Furthermore, we segment the short-term rental supply based on its types of accommodations, that is, shared rooms, private rooms, and entire homes, and both examine and quantify the differential effects of these types of short-term rentals on different types of hotels. This study offers a comprehensive analysis regarding the impact of multiple short-term rental platforms on hotel performance and offers both conceptual and practical insights regarding the nature and extent of the effects that were identified.

Double, triple or quadruple hits? Exploring the impact of cybercrime on victims in the Netherlands

2021 ◽  
pp. 026975802110106
Author(s):  
Raoul Notté ◽  
E.R. Leukfeldt ◽  
Marijke Malsch
Keyword(s):  
Public Opinion ◽  
Literature Review ◽  
The Netherlands ◽  
Public Discourse ◽  
Moral Judgments ◽  
Victim Blaming ◽  
High Prevalence ◽  
Different Types ◽  
The Impact ◽  
Insight Into

This article explores the impact of online crime victimisation. A literature review and 41 interviews – 19 with victims and 22 with experts – were carried out to gain insight into this. The interviews show that most impacts of online offences correspond to the impacts of traditional offline offences. There are also differences with offline crime victimisation. Several forms of impact seem to be specific to victims of online crime: the substantial scale and visibility of victimhood, victimisation that does not stop in time, the interwovenness of online and offline, and victim blaming. Victims suffer from double, triple or even quadruple hits; it is the accumulation of different types of impact, enforced by the limitlessness in time and space, which makes online crime victimisation so extremely invasive. Furthermore, the characteristics of online crime victimisation greatly complicate the fight against and prevention of online crime. Finally, the high prevalence of cybercrime victimisation combined with the severe impact of these crimes seems contradictory with public opinion – and associated moral judgments – on victims. Further research into the dominant public discourse on victimisation and how this affects the functioning of the police and victim support would be valuable.

scholarly journals Can Architectural Surfaces Capture Atmospheric Particulate Matter Like Trees? A Design Strategy to Mimic Leaf Traits

2021 ◽  
Vol 13 (14) ◽  
pp. 7637
Author(s):  
Taekyoung Lee ◽  
Jieun Cha ◽  
Sohyun Sung
Keyword(s):  
Leaf Traits ◽  
Design Strategy ◽  
Atmospheric Particulate Matter ◽  
Porous Surface ◽  
Base Surface ◽  
Different Types ◽  
Pm2.5 And Pm10 ◽  
Micro Morphology ◽  
The Impact ◽  
Cluster Pattern

Trees’ ability to capture atmospheric Particular Matter (PM) is related to morphological traits (shape, size, and micro-morphology) of the leaves. The objectives of this study were (1) to find out whether cluster pattern of the leaves is also a parameter that affects trees’ PM capturing performance and (2) to apply the cluster patterns of the leaves on architectural surfaces to confirm its impact on PM capturing performance. Two series of chamber experiments were designed to observe the impact of cluster patterns on PM capturing performance whilst other influential variables were controlled. First, we exposed synthetic leaf structures of different cluster patterns (a large and sparsely arranged cluster pattern and a small and densely arranged cluster pattern) to artificially generated PM in a chamber for 60 min and recorded the changing levels of PM2.5 and PM10 every minute. The results confirmed that the small and densely arranged cluster pattern has more significant effect on reducing PM2.5 and PM10 than the large and sparsely arranged cluster pattern. Secondly, we created three different types of architectural surfaces mimicking the cluster patterns of the leaves: a base surface, a folded surface, and a folded and porous surface. The surfaces were also exposed to artificially generated PM in the chamber and the levels of PM2.5 and PM10 were recorded. The results confirmed that the folded and porous surface has a more significant effect on reducing PM2.5 and PM10 than other surfaces. The study has confirmed that the PM capturing performance of architectural surfaces can be improved by mimicking cluster pattern of the leaves.

scholarly journals Threat or Corrective? Assessing the Impact of Populist Parties in Government on the Qualities of Democracy: A 19-Country Comparison

2021 ◽  
pp. 1-21
Author(s):  
Davide Vittori
Keyword(s):  
Negative Impact ◽  
Quality Of Democracy ◽  
Clear Cut ◽  
Liberal Democratic ◽  
Country Comparison ◽  
Democratic Regimes ◽  
Different Types ◽  
The Impact

Abstract Scholars have long debated whether populism harms or improves the quality of democracy. This article contributes to this debate by focusing on the impact of populist parties in government. In particular, it inquires: (1) whether populists in government are more likely than non-populists to negatively affect the quality of democracies; (2) whether the role of populists in government matters; and (3) which type of populism is expected to negatively affect the quality of liberal-democratic regimes. The results find strong evidence that the role of populists in government affects several qualities of democracy. While robust, the findings related to (2) are less clear-cut than those pertaining to (1). Finally, regardless of their role in government, different types of populism have different impacts on the qualities of democracy. The results show that exclusionary populist parties in government tend to have more of a negative impact than other forms of populism.

The Impact of Mental States on Semi-autonomous Driving Takeover Performance: A Systematic Review

2020 ◽  
Vol 64 (1) ◽  
pp. 1372-1376
Author(s):  
Gaojian Huang ◽  
Christine Petersen ◽  
Brandon J. Pitts
Keyword(s):  
Systematic Review ◽  
Autonomous Vehicles ◽  
Response Times ◽  
Autonomous Driving ◽  
Mental States ◽  
Manual Control ◽  
Monitoring Systems ◽  
Wide Range ◽  
Different Types ◽  
The Impact

Semi-autonomous vehicles still require drivers to occasionally resume manual control. However, drivers of these vehicles may have different mental states. For example, drivers may be engaged in non-driving related tasks or may exhibit mind wandering behavior. Also, monitoring monotonous driving environments can result in passive fatigue. Given the potential for different types of mental states to negatively affect takeover performance, it will be critical to highlight how mental states affect semi-autonomous takeover. A systematic review was conducted to synthesize the literature on mental states (such as distraction, fatigue, emotion) and takeover performance. This review focuses specifically on five fatigue studies. Overall, studies were too few to observe consistent findings, but some suggest that response times to takeover alerts and post-takeover performance may be affected by fatigue. Ultimately, this review may help researchers improve and develop real-time mental states monitoring systems for a wide range of application domains.

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