3,171 research outputs found

    Flash Point Measurements and Modeling for Ternary Partially Miscible Aqueous­Organic Mixtures

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    Flash point is the most important variable used to characterize the fire and explosion hazard of liquids. This paper presents the first partially miscible aqueousorganic mixtures flash point measurements and modeling for the ternary type-I mixtures, water + ethanol + 1-butanol, water + ethanol + 2-butanol, and the type-II mixture, water + 1-butanol + 2-butanol. Results reveal that the flash points are constant in each tie line. Handling the non-ideality of the liquid phase through the use of activity coefficient models, the general flash-point model of Liaw et al. extended to partially miscible mixtures predicts the experimental data well when using literature LLE and the VLE activity coefficient model binary parameters to estimate sequentially the span and flash point in each tie line and the flash point in the mutual solubility region, respectively. The constant flash-point behavior in a tie line is also observed and predicted, in agreement with the VLLE tie line property that a single vapor is in equilibrium with all liquid composition on a tie line. For the aqueousorganic mixtures here studied, a deviation between prediction and measurements is observed, arising from the failure of the constant lower flammable limit assumption in the mutual solubility inert-rich region. Potential application for the model concerns the assessment of fire and explosion hazards and the development of inherently safer designs for chemical processes containing partially miscible aqueousorganic mixtures

    Case Study: Robin Hood or Criminal? The Case of a Bank Loan Officer

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    Employees who deviate from established rules at work face suspension or termination from their employment. Yet, knowing these dire consequences employees may still find themselves walking on a different path of business policy. Most employee wrongful conduct is done with the specific intent of benefitting the employee. In some cases, the authorities are brought in to intervene and criminal charges are brought against the employee, as in the case of embezzlement. Some acts are done by employees who do not believe in their company’s rules and are willing to deviate from them, not for their own benefit, but rather for the benefit of others. These employees are simply terminated. When a loan officer fails to follow established bank-regulations is that an employer/employee discipline matter or a violation of federal law? Most observers would not have a problem criminally punishing a loan officer who personally benefits from such wrongful conduct. Such an act could progress to criminal charges under Section 18 USC Section 1344 punishable by a maximum fine of $1,000,000 and 30 years imprisonment

    Resistive switching induced by electronic avalanche breakdown in GaTa4_4Se8−x_{8-x}Tex_x narrow gap Mott Insulators

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    Mott transitions induced by strong electric fields are receiving a growing interest. Recent theoretical proposals have focused on the Zener dielectric breakdown in Mott insulators, however experimental studies are still too scarce to conclude about the mechanism. Here we report a study of the dielectric breakdown in the narrow gap Mott insulators GaTa4_4Se8−x_{8-x}Tex_x. We find that the I-V characteristics and the magnitude of the threshold electric field (Eth_{th}) do not correspond to a Zener breakdown, but rather to an avalanche breakdown. Eth_{th} increases as a power law of the Mott Hubbard gap (Eg_g), in surprising agreement with the universal law Eth_{th} ∝\proptoEg_g2.5^{2.5} reported for avalanche breakdown in semiconductors. However, the delay time for the avalanche that we observe in Mott insulators is over three orders of magnitude longer than in conventional semiconductors. Our results suggest that the electric field induces local insulator-to-metal Mott transitions that create conductive domains which grow to form filamentary paths across the sample

    Blood is Not Always Thicker than Water: A Family Business Case Study

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    According to the US Census Bureau, 90% of businesses in the U.S. are family-owned or controlled. Unfortunately, the succession rates for family-owned businesses are dismal. Only 30% survive a transfer from the founder to a child and only 11% survive a second transfer to the third generation. Two major factors that contribute to this are lack of succession planning and failure to deal with family conflict, both of which are management failures and are often intertwined. Failure to properly manage the family fosters a sense of unfairness, unequal workload, and perhaps a free-rider problem among family members. This not only causes management issues in the business, but friction among family members, which potentially leads to unethical, and sometimes illegal, actions. This case study details such a very successful family-owned business founded by a father and managed by him and his two sons. However, conflicts appear with the third generation. One grandson does the unthinkable, i.e., embezzles from the family business. Rather than stop him, his brother and father join in. To complicate factors more, 60% of the stock is controlled by the family and 40% is publicly traded. Although there were some red flags, no one notices thereby failing in their duties to the corporation. This case also deals with the issue of succession; should the business be divided by family groups or distributed equally among the third generation? Students are required to identify ethical dilemmas, find the lapses in judgement by each party involved, and recommend managerial actions that should have been taken to prevent this situation

    Cartographie Automatique des Zones InondĂ©es et Evaluation des Dommages dans le District d’Abidjan Ă  l'Aide de l'Imagerie Satellitaire Radar Sentinel-1 Depuis Google Earth Engine

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    La connaissance de la localisation et de l'Ă©tendue des zones inondĂ©es dans le District d’Abidjan au sud de la CĂŽte d'Ivoire, frĂ©quemment affectĂ©e par les inondations pendant la saison des pluies et avec une rĂ©ponse diffĂ©rente des prĂ©cipitations et du ruissellement dans chacun de ses sous-bassins, a des implications importantes pour la gestion du risque. L'objectif de cette Ă©tude est de gĂ©nĂ©rer automatiquement des cartes de l'Ă©tendue des inondations dans le district d'Abidjan et d’évaluer les zones touchĂ©es, grĂące au potentiel du cloud, aux algorithmes d'apprentissage automatique et Ă  l'utilisation de donnĂ©es provenant de divers capteurs de tĂ©lĂ©dĂ©tection optique Sentinel-2, SAR Sentinel-1 et MNT Polsar. L’approche mĂ©thodologique a consistĂ© Ă  implĂ©menter dans Google Earth Engine un script qui permet d'abord de cartographier avec prĂ©cision l'Ă©tendue des zones inondĂ©es en utilisant une mĂ©thode de dĂ©tection des changements basĂ©e sur les donnĂ©es Sentinel-1 (SAR) avant et aprĂšs une crue spĂ©cifique. Ensuite, les diffĂ©rentes classes d'enjeux (telles que les cultures, les zones habitĂ©es, les bĂątiments, les routes et la densitĂ© de la population) ont Ă©tĂ© extraites Ă  partir de diverses sources de donnĂ©es gratuites et superposĂ©es aux zones inondĂ©es cartographiĂ©es, permettant ainsi d'Ă©valuer la superficie des zones touchĂ©es. De plus, une interface web a Ă©tĂ© conçue Ă  l'aide des packages de Google Earth Engine, offrant Ă  l'utilisateur la possibilitĂ© de visualiser l'Ă©tendue des zones inondĂ©es et les cartes des enjeux de surfaces affectĂ©s, avec une estimation statistique, pour une date donnĂ©e dans l'intervalle allant de 2013 Ă  la date actuelle. La cartographie des zones inondĂ©es Ă  la date du 20 juin 2020 a rĂ©vĂ©lĂ© une superficie totale de 21 763,05 hectares de zones inondĂ©es dans le District d'Abidjan. Une estimation des dĂ©gĂąts causĂ©s par cette crue du 20 juin 2020 indique que 13 170,17 hectares d'enjeux ont Ă©tĂ© affectĂ©s en moyenne, ce qui reprĂ©sente 60,5 % des zones inondĂ©es. Cette rĂ©partition se dĂ©compose en 7 875,06 hectares (soit 36,2 %) de terres agricoles touchĂ©es et 5 295,11 hectares (soit 24,3 %) de zones urbaines touchĂ©es, impactant en moyenne 64 877 personnes. Les rĂ©sultats de cette Ă©tude ont permis de constater que la partie centrale de la zone d'Ă©tude, au-dessus de la lagune, prĂ©sente le plus grand potentiel de risque d'inondation en raison de la morphologie du terrain et de la vulnĂ©rabilitĂ© Ă©levĂ©e des zones construites qui occupent la plaine inondable.   Understanding the location and extent of flooded areas in the Abidjan District in southern CĂŽte d'Ivoire, which is frequently affected by floods during the rainy season, and with a unique response to precipitation and runoff in each of its sub-basins, has significant implications for risk management. The objective of this study is to automatically generate maps of flood extent in the Abidjan district and assess the affected areas, leveraging the potential of the cloud, machine learning algorithms, and data from various optical remote sensing sensors, including Sentinel-2, Sentinel-1 SAR, and Polsar DTM. The methodological approach involved implementing a script in Google Earth Engine that first accurately maps the extent of flooded areas using a change detection method based on Sentinel-1 (SAR) data before and after a specific flood event. Then, various asset classes (such as crops, inhabited areas, buildings, roads, and population density) were extracted from various free data sources and overlaid on the mapped flooded areas, allowing for an assessment of the affected area. Additionally, a web interface was designed using Google Earth Engine packages, providing users with the ability to visualize the extent of flooded areas and maps of affected asset classes, along with statistical estimates, for a given date within the range from 2013 to the present. The mapping of flooded areas as of June 20, 2020, revealed a total area of 21,763.05 hectares of flooded zones in the Abidjan District. An estimation of the damages caused by this flood on June 20, 2020, indicates that an average of 13,170.17 hectares of assets were affected, representing 60.5% of the flooded areas. This breakdown includes 7,875.06 hectares (36.2%) of affected agricultural lands and 5,295.11 hectares (24.3%) of affected urban areas, impacting an average of 64,877 peoples. The results of this study have shown that the central part of the study area, above the lagoon, has the highest potential for flood risk due to the terrain morphology and the high vulnerability of built-up areas occupying the floodplain

    Cartographie Automatique des Zones InondĂ©es et Evaluation des Dommages dans le District d’Abidjan Ă  l'Aide de l'Imagerie Satellitaire Radar Sentinel-1 Depuis Google Earth Engine

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    La connaissance de la localisation et de l'Ă©tendue des zones inondĂ©es dans le District d’Abidjan au sud de la CĂŽte d'Ivoire, frĂ©quemment affectĂ©e par les inondations pendant la saison des pluies et avec une rĂ©ponse diffĂ©rente des prĂ©cipitations et du ruissellement dans chacun de ses sous-bassins, a des implications importantes pour la gestion du risque. L'objectif de cette Ă©tude est de gĂ©nĂ©rer automatiquement des cartes de l'Ă©tendue des inondations dans le district d'Abidjan et d’évaluer les zones touchĂ©es, grĂące au potentiel du cloud, aux algorithmes d'apprentissage automatique et Ă  l'utilisation de donnĂ©es provenant de divers capteurs de tĂ©lĂ©dĂ©tection optique Sentinel-2, SAR Sentinel-1 et MNT Polsar. L’approche mĂ©thodologique a consistĂ© Ă  implĂ©menter dans Google Earth Engine un script qui permet d'abord de cartographier avec prĂ©cision l'Ă©tendue des zones inondĂ©es en utilisant une mĂ©thode de dĂ©tection des changements basĂ©e sur les donnĂ©es Sentinel-1 (SAR) avant et aprĂšs une crue spĂ©cifique. Ensuite, les diffĂ©rentes classes d'enjeux (telles que les cultures, les zones habitĂ©es, les bĂątiments, les routes et la densitĂ© de la population) ont Ă©tĂ© extraites Ă  partir de diverses sources de donnĂ©es gratuites et superposĂ©es aux zones inondĂ©es cartographiĂ©es, permettant ainsi d'Ă©valuer la superficie des zones touchĂ©es. De plus, une interface web a Ă©tĂ© conçue Ă  l'aide des packages de Google Earth Engine, offrant Ă  l'utilisateur la possibilitĂ© de visualiser l'Ă©tendue des zones inondĂ©es et les cartes des enjeux de surfaces affectĂ©s, avec une estimation statistique, pour une date donnĂ©e dans l'intervalle allant de 2013 Ă  la date actuelle. La cartographie des zones inondĂ©es Ă  la date du 20 juin 2020 a rĂ©vĂ©lĂ© une superficie totale de 21 763,05 hectares de zones inondĂ©es dans le District d'Abidjan. Une estimation des dĂ©gĂąts causĂ©s par cette crue du 20 juin 2020 indique que 13 170,17 hectares d'enjeux ont Ă©tĂ© affectĂ©s en moyenne, ce qui reprĂ©sente 60,5 % des zones inondĂ©es. Cette rĂ©partition se dĂ©compose en 7 875,06 hectares (soit 36,2 %) de terres agricoles touchĂ©es et 5 295,11 hectares (soit 24,3 %) de zones urbaines touchĂ©es, impactant en moyenne 64 877 personnes. Les rĂ©sultats de cette Ă©tude ont permis de constater que la partie centrale de la zone d'Ă©tude, au-dessus de la lagune, prĂ©sente le plus grand potentiel de risque d'inondation en raison de la morphologie du terrain et de la vulnĂ©rabilitĂ© Ă©levĂ©e des zones construites qui occupent la plaine inondable.   Understanding the location and extent of flooded areas in the Abidjan District in southern CĂŽte d'Ivoire, which is frequently affected by floods during the rainy season, and with a unique response to precipitation and runoff in each of its sub-basins, has significant implications for risk management. The objective of this study is to automatically generate maps of flood extent in the Abidjan district and assess the affected areas, leveraging the potential of the cloud, machine learning algorithms, and data from various optical remote sensing sensors, including Sentinel-2, Sentinel-1 SAR, and Polsar DTM. The methodological approach involved implementing a script in Google Earth Engine that first accurately maps the extent of flooded areas using a change detection method based on Sentinel-1 (SAR) data before and after a specific flood event. Then, various asset classes (such as crops, inhabited areas, buildings, roads, and population density) were extracted from various free data sources and overlaid on the mapped flooded areas, allowing for an assessment of the affected area. Additionally, a web interface was designed using Google Earth Engine packages, providing users with the ability to visualize the extent of flooded areas and maps of affected asset classes, along with statistical estimates, for a given date within the range from 2013 to the present. The mapping of flooded areas as of June 20, 2020, revealed a total area of 21,763.05 hectares of flooded zones in the Abidjan District. An estimation of the damages caused by this flood on June 20, 2020, indicates that an average of 13,170.17 hectares of assets were affected, representing 60.5% of the flooded areas. This breakdown includes 7,875.06 hectares (36.2%) of affected agricultural lands and 5,295.11 hectares (24.3%) of affected urban areas, impacting an average of 64,877 peoples. The results of this study have shown that the central part of the study area, above the lagoon, has the highest potential for flood risk due to the terrain morphology and the high vulnerability of built-up areas occupying the floodplain

    Cartographie Automatique des Zones InondĂ©es et Evaluation des Dommages dans le District d’Abidjan depuis Google Earth Engine

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    L'objectif de cette Ă©tude est de gĂ©nĂ©rer automatiquement des cartes de l'Ă©tendue des zones inondĂ©es dans le district d'Abidjan et d’évaluer les dommages causĂ©s. L’approche mĂ©thodologique a consistĂ© Ă  cartographier l'Ă©tendue des zones inondĂ©es en utilisant une mĂ©thode de dĂ©tection des changements basĂ©e sur les donnĂ©es Sentinel-1 (SAR) avant et aprĂšs une crue spĂ©cifique. Ensuite, les diffĂ©rentes classes d'enjeux (telles que les cultures, les zones habitĂ©es, les bĂątiments, les routes et la densitĂ© de la population) ont Ă©tĂ© extraites Ă  partir de diverses sources de donnĂ©es gratuites. Puis la superficie des enjeux affectĂ©s a Ă©tĂ© Ă©valuĂ©e, en superposant les classes d’enjeux sur les zones inondĂ©es. De plus, une interface web a Ă©tĂ© conçue Ă  l'aide des packages de Google Earth Engine. Cette interface web offre Ă  l'utilisateur la possibilitĂ© de visualiser l'Ă©tendue des zones inondĂ©es et les cartes des enjeux affectĂ©s, avec une estimation statistique, pour une date donnĂ©e dans l'intervalle allant de 2015 Ă  la date actuelle. La cartographie des zones inondĂ©es Ă  la date du 25 juin 2020 a rĂ©vĂ©lĂ© une superficie totale de 25219,23 hectares de zones inondĂ©es soit 11,50% de la superficie totale du District d’Abidjan. Une estimation des dĂ©gĂąts causĂ©s par cette crue indique que 22 307,53 hectares d'enjeux ont Ă©tĂ© affectĂ©s en moyenne, ce qui reprĂ©sente 88,45 % des zones inondĂ©es. Cette rĂ©partition se dĂ©compose en 13 538,49 hectares (soit 53,68 %) de terres agricoles touchĂ©es et 8 769,04 hectares (soit 34,77 %) de zones urbaines touchĂ©es, impactant en moyenne 35 065 personnes. Les rĂ©sultats de cette Ă©tude ont permis de constater que la partie centrale de la zone d'Ă©tude, au-dessus de la lagune, prĂ©sente le plus grand potentiel de risque d'inondation en raison de la morphologie du terrain et de la vulnĂ©rabilitĂ© Ă©levĂ©e des zones construites qui occupent la plaine inondable.  The objective of this study is to automatically generate maps of the extent of flooded areas in the Abidjan district and assess the resulting damages. The methodological approach involved mapping the extent of flooded areas using a change detection method based on Sentinel-1 (SAR) data before and after a specific flood event. Subsequently, various classes of assets, such as crops, residential areas, buildings, roads, and population density, were extracted from various free data sources. The affected asset areas were then evaluated by overlaying the asset classes on the flooded areas. Furthermore, a web interface was designed using Google Earth Engine packages. This web interface allows users to visualize the extent of flooded areas and maps of the affected assets, along with statistical estimates, for a specific date within the interval from 2015 to the current date. Mapping of the flooded areas as of June 25, 2020, revealed a total area of 25219.23 hectares of flooded areas, representing 11.50% of the total area of the Abidjan District. An estimation of the damages caused by this flood indicates that, on average, 22307.53 hectares of assets were affected, accounting for 88.45% of the flooded areas. This distribution breaks down into 13538.49 hectares (53.68%) of affected agricultural lands and 8769.04 hectares (34.77%) of affected urban areas, impacting an average of 35,065 people. The study results revealed that the central part of the study area, located above the lagoon, presents the highest flood risk potential due to the terrain's morphology and the high vulnerability of built-up areas occupying the floodplain
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