We report results from a study on electrical breakdown in liquid helium using near-uniform-field stainless steel electrodes with stressed area of $\sim$0.725 cm$^2$. The distribution the field is obtained for temperatures between 1.7 K and 4.0 K, pressures saturated vapor pressure 626 Torr, different surface polishes. A data-based approach determining electrode-surface-area scaling presented. d...

The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. An improved single-cell photonic band-gap (PBG) structure with an inner row of elliptical rods (PBG-E) was tested with high power at a 60 Hz repetition rate at X-band (11.424 GHz), achieving a gradient of 128 MV=m at a breakdown probability of 3:6 Â 10 À3 per pulse per meter at...

People working with ad-hoc collaboration tools suffer from information overload and information scatter. Our five-month study of project managers found their work comprised of fragmented activities scattering in task, people and application. However, these loosely coupled collaborative activities were implicitly organized by hierarchical activity threads through intrusion and digression, and ge...

Results on hard diffraction from CDF are reviewed with emphasis on the determination of the diffractive structure function of the (anti)proton from single diffractive and double Pomeron exchange dijet production. Comparison of the diffractive dijet results with predictions based on diffractive deep inelastic scattering at HERA shows a breakdown of conventional QCD factorization. A similar break...

We present further analyses of the finite-temperature phase structure of lattice QCD with the Wilson quark action based on spontaneous breakdown of parity-flavor symmetry. Results are reported on (i) an explicit demonstration of spontaneous breakdown of parity-flavor symmetry beyond the critical line, (ii) phase structure and order of chiral transition for the case of Nf = 4 flavors, and (iii) ...

In order to understand the performance of photonic bandgap (PBG) structures under realistic high gradient, high power, high repetition rate operation, a PBG accelerator structure was designed and tested at X-Band (11.424 GHz). The structure consisted of a single test cell with matching cells before and after the structure. The design followed principles previously established in testing a serie...

We present a method to generate models for trees in which we first create a weighted graph, organized based on the Yao graph, then place endpoints and root point and plan least-cost paths from endpoints to the root point. The collection of resulting paths forms a branching structure. We create a hierarchical tree structure by placing subgraphs around each endpoint and beginning again through so...