Organizational speed as a dynamic capability: Toward a holistic perspective

Current research on organizational speed has been disjointed, which has left organizational speed as an underdeveloped area of study. In this essay, we expand the view of organizational speed as a multidimensional gestalt-like construct that may influence firm performance and competitive advantage. We offer a capability-based definition of organizational speed and identify and review the building blocks of organizational speed. We propose new avenues and questions for future research based on our perspective

Design Of Spouted Fluidized Bed Computational Models For Advanced Energy Applications

Fluidization process technology has been widely studied since its first commercial uses during the 1920s. Initially, developmental progress was slow as fluidized beds are complex in design and often hard to scale up in size. However, with the emergence of computational fluid dynamics (CFD), researchers were able to simulate wide ranges of fluidization and create new fluidization designs to help solve complex problems. This study aims to determine if CFD can be effective in designing spout-fluid beds with draft tubes for advanced energy applications. CFD has been employed for studying the fluidization characteristics, design, and optimization of spouted beds. However, they have mainly been used in conjunction with large (Geldart D) particles where the drag forces dominate the wall frictional and collisional losses. Subsequently, identifying the correct drag law with the Geldart D particles has often deemed to be sufficient to get an accurate fluidization pattern. Additionally, the more accurate Discrete Element Method (DEM) methodology where the forces and motion of the individual particles are tracked has also been employed when the numbers of particles are computationally manageable (between 104 and 105). In this project, the feasibility of employing Geldart B particles in spouted bed reactors are explored. In lieu of the fact that the number of resulting particles make the use of the DEM framework unfeasible we employ the Two-Fluid Modeling (TFM) methodology in this scenario. Further, frictional and collisional losses become more important here (due to smaller particle sizes) which makes the selection of appropriate interaction terms in the TFM framework all the more important. The first CFD software used in this study was Multiphase Flow with Interphase eXchanges (MFiX), an open-source CFD software created and maintained by the National Energy and Technology Laboratory (NETL). The purpose of using the MFiX software was to design a spout-fluid bed with a draft tube that may be used in Chemical Looping Combustion (CLC) applications with the goals of minimizing the pressure drop and maximizing the residence time. Specifically, the drag law, coordinate system, and grid/mesh resolution were studied to determine the optimal design settings. The optimal design settings were determined by comparing the simulation results to previous experimental work conducted. For the drag law comparison, three commonly used drag laws (Syamlal-O’Brien, Gidaspow, Wen-Yu) in fluidized bed simulations were employed to select the law that gives the optimal performance results in the model. Results of the drag law comparisons showed that the Syamlal-O’Brien model (with appropriate parameters representative of the fluidizing particle) is the best drag law for the spouted fluid bed with a draft tube. Therefore, it was employed in the comparisons of the co-ordinate system and mesh resolution The next parameter studied was the co-ordinate system set for the model. Due to the high computational cost associated with 3D simulations, it is traditional to simulate the fluidization behavior using 2D axisymmetric grids or even 2D planar grids. While 2D axisymmetric grids are an accurate representation of a cylindrical reactor, the imposition of symmetric boundary conditions along the axis can lead to unrealistic jetting behavior (which will be exacerbated in a spouted bed unit due to high centerline velocity). While many studies have shown that 2D planar and 2D axisymmetric result in similar fluidization characteristics in bubbling beds, the importance of this assumption in spouted bed units needs to be ascertained. The results of our model showed that the cylindrical 2-D axisymmetric simulation predictions were qualitatively similar to the fluidization behavior that was observed experimentally. The final MFiX parameter studied was the grid/mesh resolution of the model. In bubbling beds, a cell size of 9 diameters has been deemed adequate to capture pressure drop. However, we need to ascertain if this is applicable in spouted beds with draft tubes. However, a comparison of pressure drop predictions from employing cell sizes of 11 particle diameters and 6 particle diameters showed that grid convergence was not yet achieved. Therefore, further research would be required to determine the optimal cell size for grid independence in spouted bed systems. In the second part of this study, the CFD software ANSYS Fluent was utilized to determine the effectiveness of a spout-fluid bed with a draft tube for the density separation of particles. This specific design function may be desirable for the continuous removal of a product such as carbon black separation in the pyrolysis of tires. ANSYS Fluent was selected for this portion of the study due to its ability to handle complex geometry and enable the specification of phase-specific interaction terms (drag laws and collision models). The different particles investigated were of 300 and 100 µm diameters and 1200 and 4000 kg/m3 densities respectively. The results of the CFD simulations showed that a stable spout-fluid bed with a draft tube design could be created. However, no significant separation of particles was achieved. Additionally, CFD simulations and experimental trials were conducted on conical bottom spouted beds to determine if the separation of pyrite-rich minerals from coal. The results of the CFD and experiment both concluded that no separation was achievable. The recovery of coal product was only 5% of the original mass and the ash content of the product coal decreased to 25-28% when the target separation criteria was less than 20% ash. Therefore, we concluded for effective density separation of Geldart B particles design modifications to the spouted bed reactor should be investigated in future work

USSR Space Life Sciences Digest, issue 1

The first issue of the bimonthly digest of USSR Space Life Sciences is presented. Abstracts are included for 49 Soviet periodical articles in 19 areas of aerospace medicine and space biology, published in Russian during the first quarter of 1985. Translated introductions and table of contents for nine Russian books on topics related to NASA's life science concerns are presented. Areas covered include: botany, cardiovascular and respiratory systems, cybernetics and biomedical data processing, endocrinology, gastrointestinal system, genetics, group dynamics, habitability and environmental effects, health and medicine, hematology, immunology, life support systems, man machine systems, metabolism, musculoskeletal system, neurophysiology, perception, personnel selection, psychology, radiobiology, reproductive system, and space biology. This issue concentrates on aerospace medicine and space biology

Bridging the gap between research and agile practice: an evolutionary model

There is wide acceptance in the software engineering field that industry and research can gain significantly from each other and there have been several initiatives to encourage collaboration between the two. However there are some often-quoted challenges in this kind of collaboration. For example, that the timescales of research and practice are incompatible, that research is not seen as relevant for practice, and that research demands a different kind of rigour than practice supports. These are complex challenges that are not always easy to overcome. Since the beginning of 2013 we have been using an approach designed to address some of these challenges and to bridge the gap between research and practice, specifically in the agile software development arena. So far we have collaborated successfully with three partners and have investigated three practitioner-driven challenges with agile. The model of collaboration that we adopted has evolved with the lessons learned in the first two collaborations and been modified for the third. In this paper we introduce the collaboration model, discuss how it addresses the collaboration challenges between research and practice and how it has evolved, and describe the lessons learned from our experience

Paradoxes versus formalism in economics. Evidence from the early years of game theory and experimental economics

This paper argues that the acceptance of two recent methodological advances in economics, namely game theory and laboratory experimentation, was affected by the history dependence constraining the formalization of economics. After an early period in which the two methods were coolly received by economists because their applications challenged some basic hypotheses of mainstream economics, their subsequent acceptance was the result of the corroboration of those same hypotheses. However, the recent emergence of some paradoxes has finally revealed that the effectiveness of game theory and experimental techniques in economics is improved when descriptively implausible and normatively unsatisfactory assumptions such as the centrality of individual maximization in decision theory and the definition of rationality as consistency in preferences are revised.paradoxes, game theory, experiments, individual maximization, economic rationality

The serve clock reduced rule violations, but did not speed up the game: A closer look at the inter-point time at the 2018 US Open

After treating time rule violations as a trivial offense over the past, tennis associations in 2018 permanently introduced an on-court serve clock to make sure that players do not exceed the time limit between points. In this study, we investigated the influence of this technological officiating aid at its first use in Grand Slam tennis at the 2018 US Open. By investigating time intervals between 2135 points at the Men’s single tournament we found that the share of rule violations decreased (26.3%), but the average time did not (21.6 s) compared to previous studies. We could further confirm that the players still use this time interval for tactical reasons and to recover after longer rallies. In addition, the umpires, which do not show any reputation bias, have a significant influence on the inter-point time as well. Based on these findings we suggest introducing a serve clock that is started automatically. Further, we argue that a dynamic time limit, which takes the intensity of the previous rally into account, would be more appropriate. Players could be granted more time for recovery after longer rallies, but less time after shorter ones in order to reach the intended goals regarding pace of play