Using the Kaleidoscope Career Model to Examine Generational Differences in Work Attitudes

The purpose of this paper is to examine, utilising the Kaleidoscope Career Model, whether members of the Baby Boom generation and Generation X differ in their needs for authenticity, balance, and challenge. This paper won the 2009 McGraw Hill Irwin Distinguished Paper Award at the Southwestern Academy of Management

CLC, a promising concept with challenging development issues

Chemical Looping Combustion (CLC) is a promising technique to achieve fuel combustion in a nitrogen free atmosphere, therefore giving the possibility to separate and store or use CO2. Several potential applications are considered in the field of power generation with gas, liquid and solid fuels. In the Carbon Capture, Storage and Utilization (CCSU) context, energy penalty is reduced compared to other routes. In addition, other applications of Chemical Looping are considered in the field of H2 production or gasification for instance. In the past years, a huge effort has been conducted worldwide to investigate CLC materials and process issues. In 2008, IFPEN and Total have started an ambitious collaboration to develop CLC applications. Nowadays, the CLC concept is well demonstrated at the pilot scale. The next step is to demonstrate the technology over time at larger scale. However, for further developments, the challenges are numerous and will be discussed, both on market and technical aspects. Short term market is limited. Uncertainties around CO2 emission market and storage issues are related to CO2 policy and public acceptance of storage which still must evolve in the right direction... Financing of demonstration units in this context is challenging and other applications of CLC have to be investigated. The industrial use of synthetic metal oxides or natural ores at large scale generates a lot of issues related to availability, price, waste disposal, health and safety, additionally to chemical and mechanical stability over time, reactivity, and oxygen transfer capacity. Chemical looping reactor and process technology concepts have to be explored, developed, modeled and scaled-up in order to ensure adequate power production together with good gas solid contact and reaction requirement, controlled circulation of mixtures of particle (oxygen carrier, ash, solid fuel for instance). All these points should be considered at very large scale for CCS applications in order to minimize energy penalty and cost in severe operating conditions (temperatures above 800°C and intense solid circulation). Technical challenges remain to be solved and proven with large demonstration over long periods of time. In this context, research in the field of fluidization technology is essential and we will address a couple of key points already investigated at IFPEN and related to control of solid circulation, oxygen carrier attrition, conceptual design of CLC reactors and process performance

Synthesis of an alkylmagnesium amide and interception of a ring-opened isomer of the important utility amide 2,2,6,6-tetramethylpiperidide (TMP)

Two new magnesium complexes containing the important utility amide 2,2,6,6-tetramethylpiperidide (TMP) have been synthesised. Treating the magnesium bis(alkyl) reagent (Me3SiCH2)2Mg with a molar equivalent of TMP(H) in hydrocarbon medium produces the dimeric alkylmagnesium amide complex [(Me3SiCH2)Mg(μ-TMP)]22, which was isolated in high yield. X-ray crystallography revealed that 2 was an unsymmetrical dimer as unusually the two TMP ligands adopt different conformations – one a chair, the other a twisted boat. Solution studies (multinuclear NMR and DOSY NMR spectroscopies) show that 2 undergoes a monomerisation and Schlenk equilibrium in d8-THF. When (Me3SiCH2)2Mg was reacted with two molar equivalents of TMP(H) in hydrocarbon medium [in an effort to prepare Mg(TMP)2] a crystalline sample of a surprising product, a tetranuclear triheteroanionic amide-alkoxide-amidoalkene [(TMP)Mg(μ-TMP){μ-N(H)C(Me)2CH2CH2CH2C(Me) = CH2}Mg(μ-OCH2SiMe3)]23 was obtained. Complex 3 contains two unexpected anions, namely the alkoxide produced via oxygen insertion into a Mg–C bond, and the primary amidoalkene which is produced via ring opening of the TMP anion

Reflections on the 'History and Historians' of the black woman's role in the community of slaves: enslaved women and intimate partner sexual violence

Taking as points of inspiration Peter Parish’s 1989 book, Slavery: History and Historians, and Angela Davis’s seminal 1971 article, “Reflections on the black woman’s role in the community of slaves,” this probes both historiographically and methodologically some of the challenges faced by historians writing about the lives of enslaved women through a case study of intimate partner violence among enslaved people in the antebellum South. Because rape and sexual assault have been defined in the past as non-consensual sexual acts supported by surviving legal evidence (generally testimony from court trials), it is hard for historians to research rape and sexual violence under slavery (especially marital rape) as there was no legal standing for the rape of enslaved women or the rape of any woman within marriage. This article suggests enslaved women recognized that black men could both be perpetrators of sexual violence and simultaneously be victims of the system of slavery. It also argues women stoically tolerated being forced into intimate relationships, sometimes even staying with “husbands” imposed upon them after emancipation

Gender role differences in reactions to unemployment: Exploring psychological mobility and boundaryless careers

Using Sullivan and Arthur\u27s (Sullivan & Arthur, 2006) refinement of the boundaryless career concept, this study examines whether there are gender role differences in psychological mobility (i.e., the career actor\u27s capacity to envision a variety of career options) in response to the same physical transition of unemployment. We surveyed 1095 individuals across numerous organizations and industries, and analyzed our data by generational cohort in light of evolving societal attitudes toward child rearing and breadwinning responsibilities. We found that for both Gen Xers and Baby Boomers, men with children were more likely to perceive unemployment as a defeat than women with children; and women with children were more likely to perceive unemployment as an opportunity than men with children. Despite the many historical, economic, social, and cultural changes in the environment over the past decades, traditional gender roles remain pervasive in response to unemployment. Based on the study\u27s empirical findings, we suggest critical issues for the future study of gender role differences and psychological mobility. Copyright © 2010 John Wiley & Sons, Ltd

CFD modeling of riser with Group B particles

International audience– A series of tests were conducted in a large cold flow CFB unit (18 m long riser and 30 cm in diameter) with two different Group B powders. The impact of particle nature on the riser hydrodynamics was investigated at similar operating conditions through pressure taps and extraction probes. To study the impact of particle size and sphericity, sand and glass beads were used. Resulting axial pressure profiles are very different in both the acceleration and in the fully developed region. These differences can most probably be explained by the difference in shape between the solids. Higher sphericity seems to generate smaller pressure drop. Trough extraction probe measurements, the core-annulus regime was found on the developed zone of the riser. An assessment of a commercial CFD code to predict riser flow was carried out. For glass beads, simulation results agree reasonably well with experimental pressure profiles but the core annulus structure is underpredicted. However, pressure drop along the riser is strongly underestimated in sand simulations

Influence of scale on the hydrodynamics of bubble column reactors: An experimental study in columns of 0.1, 0.4 and 1 m diameters

Measurements of liquid velocities and liquid mixing have been performed in three different bubble columns of 0.15, 0.4 and 1 m diameter with water and air, at superficial gas velocity ranging from 0.05 to 0.20 m/s with high aspect ratios (HD/D>4). Liquid velocities are determined with a Pavlov tube calibrated up to 25% of gas holdup. Axial dispersion coefficient is determined using a new method which allows accounting for the upflow and downflow regions. The experimental results allow selecting reliable correlations of the literature. The Ueyama and Miyauchi model is successfully compared with the experiments and a new correlation for the kinematic viscosity is proposed

Scale up of slurry bubble reactors

Bubble column reactors are finding increasing use in industrial practice. They are in particular appropriate to carry out highly exothermic reactions, such as methanol synthesis or Fischer-Tropsch synthesis of conversion of synthesis gas to liquid paraffins. Industrial process require important volumes of reactors, the reactor diameter can reach 10 m. To control the reaction temperature, internal heat-exchange tubes (vertical tubes) are inserted inside the reactor. This study deals with the effects of scale and the presence of internals on hydrodynamic characteristics, for scale-up purposes based on experiments in cold mockups. Our study shows that the liquid recirculation intensity depends strongly on the column diameter whereas the gas holdup is slightly affected. Two methods are proposed to predict scale effect on liquid velocity: an empirical correlation proposed in the literature and a phenomenological model. Internals guide liquid: the large scale recirculation increases but fluctuations of liquid velocity decrease. Therefore the mixing of liquid is significantly affected by the presence of internals and is not well described by the standard mono dimensional axial dispersion model. A two-dimensional model, taking into account a radially dependent axial velocity profile and both axial and radial dispersion, is therefore developed to describe the liquid mixing in a bubble column with internals