Browsing by Subject "accelerator"
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Item Editing the Pitch: Patterns of Editing Strategies of Written Pitches in a Chilean Accelerator Program(IEEE Transactions on Professional Communication, 2020-11) Cabezas, Paula; Spinuzzi, Clay; Sabaj, Omar; Varas, GermánAbstract—Background: After a six-month training program in the Chilean public accelerator Start-Up Chile, entrepreneurs are asked to update a short pitch they wrote in the submission stage to appear in the program’s online portfolio. Literature review: We reviewed relevant literature related to the pitch as well as research aiming to track changes within pitches. Research questions: 1. Which are the editing strategies used to change their pitch? 2. Do these strategies conform to specific discursive patterns? Research methodology: To answer the research questions, we designed an exploratory qualitative study to describe in depth the editing strategies used by two generations of startups, corresponding to 148 pairs of written pitches. In order to contextualize the results, we conducted two interviews with the program managers and analyzed the accelerator’s official Playbook and Technical and Administrative Requirements. Results: We identified 10 editing strategies. Of those editing strategies, “Deleting technical descriptions” is by far the most common procedure. The identified patterns can be classified into two groups, those simplifying, hedging, and focusing on certain elements of the first pitch, and those adding and specifying information of the first version. Conclusions: We conclude by discussing the strengths of this methodological approach for understanding such edits and for supporting successful edits in accelerator programs, as well as the potential for better understanding entrepreneur coachability.Item Electromagnetic Induction Launchers(IEEE, 1986-11) Driga, M. D.; Weldon, W. F.; Woodson, H. H.The electromagnetic launcher consists of a system of stator coils producing a traveling field which accelerates an armature carrying currents induced by the traveling field (induction accelerator [1,2]) or persistent currents supplied from otner sources (synchronous accelerator [2,10]). The fact that their armature has no electrical contact with the stator, essentially riding on the crest of a traveling magnetic wave, makes induction accelerators very attractive for a large number of applications. This paper is devoted exclusively to the accelerator of the induction type. Efficiency considerations require that the traveling wave should accelerate at approximately the same rate as the projectile. This can be achieved either using variable (increasing) winding pitch or a continuously increasing power supply frequency or a combination of both. A new dimension was added to the induction coaxial accelerator technology with the definition at the Center for Electromechanics at The University of Texas at Austin (CEM-UT) of a new electrical machine, the Rising Frequency Generator (RFG) representing a more attractive integrated power source for induction accelerators which had previously been forced to conform to constant frequency power supplies. This paper outlines the principles of design and shows two applications of induction coaxial launchers; a half-scale aircraft launcher in which the system also acts as an electromagnetic brake, stopping the shuttle and driving it in the opposite direction, and a high performance, 18-m long launcher capable of accelerating a 1-kg aluminum projectile to a velocity of 10 km/s at an average acceleration of 250,000 G.Item Femtosecond Pump-Probe Diagnostics Of Preformed Plasma Channels(2004-12) Zgadzaj, R.; Gaul, E. W.; Matlis, N. H.; Shvets, G.; Debus, A.; Downer, M. C.; Zgadzaj, R.; Gaul, E. W.; Matlis, N. H.; Shvets, G.; Debus, A.; Downer, M. C.We report on recent ultrafast pump-probe experiments 28 in He plasma waveguides using 800 nm, 80 fs pump pulses of 0.2 x 1018 W/cm2 peak guided intensity, and single orthogonally-polarized 800 nm probe pulses with similar to0.1% of pump intensity. The main results are: (1) We observe frequency-domain interference between the probe and a weak, depolarized component of the pump that differs substantially in mode shape from the injected pump pulse; (2) we observe spectral blue-shifts in the transmitted probe that are not evident in the transmitted pump. The evidence indicates that pump depolarization and probe blue-shifts both originate near the channel entrance.Item Go or No Go: Learning to Persuade in an Early-Stage Student Entrepreneurship Program(2020-06) Spinuzzi, Clay; Altounian, David; Pogue, GregoryAbstract—Background: Early-stage accelerator programs teach new entrepreneurs how to identify and exploit venture opportunities. In doing so, they implicitly teach these new entrepreneurs how to develop and iterate claims. But since this function of teaching persuasion has been implicit and generally unsystematic, it is unclear how well it works. Literature review: We review related literature on the venture development process, value propositions, and logic orientation (Goods-Dominant vs. Service-Dominant Logic). Research questions: 1. Does an entrepreneurship training program implicitly teach new entrepreneurs to make and iterate persuasive claims? 2. How effectively does it do so, and how can it improve? Research methodology: We examine one such accelerator program via a qualitative case study. In this case study, we collected interviews, observations, and artifacts, then analyzed them with thematic coding. Results/discussion: All teams had received previous entrepreneurship training and mentoring. However, they differed in their problem and logic orientations as well as their stage in the venture development process. These differences related to the extent to which they iterated value propositions in the program. Conclusions: We conclude with recommendations for improving how accelerator programs can better train new entrepreneurs to communicate and persuade.Item Micrometeroid Impact Simulations Using a Railgun Electromagnetic Accelerator(IEEE, 1991-01) Upshaw, J. L.; Kajs, J. P.A railgun electromagnetic (EM) accelerator was used to conduct a series of hypervelocity micrometeoroid impact simulations. The tests were designed to demonstrate that railguns can provide a repeatable means of accelerating particles between 10-4 and 10-7 g to hypervelocities within a high-vacuum flight chamber. Soda-lime glass beads were accelerated up to 11 km/s impacting into silicon, aluminum, quartz, and various proprietary targets. The railgun accelerators used were 1 m long, 12.7 mm wide, square-bore railguns. The inductance gradient for these guns was 0.32 μH/m. The conductors of the gun were made of molybdenum, and the insulating sidewalls were made of either 40% glass-filled polycarbonate or black granite. The power supply for the guns was two capacitor banks in parallel. Aluminum fuses [0.254 to 2.54 mm (1 to 10 mil) thick] with various size glass beads attached to them served as the conducting plasma on vaporization. The beads were entrained in the plasma as it formed, and were accelerated with the plasma down the gun. Gun and flight range diagnostics, along with experimental setups and results for several of the experiments, are presentedItem Multi-GeV Electron Generation Using Texas Petawatt Laser(2010-11) Wang, X.; Du, D.; Yi, S. A.; Kalmykov, S.; D'Avignon, E.; Fazel, N.; Zagdzaj, R.; Reed, S.; Dong, P.; Henderson, W.; Dyer, G.; Bernstein, A.; Gaul, E.; Martinez, M.; Shvets, G.; Ditmire, T.; Downer, M.; Wang, X.; Du, D.; Yi, S. A.; Kalmykov, S.; D'Avignon, E.; Fazel, N.; Zagdzaj, R.; Reed, S.; Dong, P.; Henderson, W.; Dyer, G.; Bernstein, A.; Gaul, E.; Martinez, M.; Shvets, G.; Ditmire, T.; Downer, M.We present simulation results and experimental setup for multi-GeV electron generation by a laser plasma wake field accelerator (LWFA) driven by the Texas Petawatt (TPW) laser. Simulations show that, in plasma of density n(e) = 2 - 4 x cm(-3), the TPW laser pulse (1.1 PW, 170 fs) can self-guide over 5 Rayleigh ranges, while electrons self-injected into the LWFA can accelerate up to 7 GeV. Optical diagnostic methods employed to observe the laser beam self-guiding, electron trapping and plasma bubble formation and evolution are discussed. Electron beam diagnostics, including optical transition radiation (OTR) and electron gamma ray shower (EGS) generation, are discussed as well.Item Pulsed Power Accelerators at CEM-UT(IEEE, 1991-06) Hayes, R.J.; Fuller, R.L; Kajs, J.P; Laughlin, R.L; Zowarka, R.C.An overview of four accelerator programs utilizing pulsed power is presented. The goals of each project, a description of the power supplies and launchers utilized and test results from each program are provided. The four projects presented illustrate a variety of uses for electromagnetic (EM) launchers and the potential advantages and disadvantages of four different launcher systems. Included in the paper are micrometeorite impact studies of 50 to 500 μm diameter glass beads accelerated up to 11 km/s with plasma armatures and 2.5- kg solid armature packages launched at 2.6 km/s (a record 8.1 MJ of muzzle energy). A compact rep-rateable augmented rail launcher and compulsator system weighing less than 1,100 kg is also described. Finally a skid mounted rep-rateable launcher system capable of providing 9 MJ of muzzle energy is discussed.