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Long-time scale molecular-dynamics subspace integration method applied to anharmonic crystals and glasses
No full textA subspace dynamics method is presented to model long time dynamical events. The method involves determining a set of vectors that span the subspace of the long time dynamics. Specifically, the vectors correspond to real and imaginary low frequency normal modes of the condensed phase system. Most importantly, the normal mode derived vectors are only used to define the subspace of low frequency motions, and the actual time dependent dynamics is fully anharmonic. The resultant projected set of Newton's equations is numerically solved for the subspace motions. Displacements along the coordinates outside the subspace are then constrained during the integration of the equations of motion in the reduced dimensional space. The method is different from traditional constraint methods in that it can systematically deduce and remove both local and collective high frequency motions of the condensed phase system with no a priori assumptions. The technique is well suited to removing large numbers of degrees of freedom, while only keeping the very low frequency global motions. The method is applied to highly anharmonic Lennard-Jones crystal and glass systems. Even in these systems with no intramolecular degrees of freedom or obvious separation of time scales, the subspace dynamics provides a speed up of approximately a factor of 5 over traditional molecular dynamics through use of a larger integration time step. In the cases illustrated here a single set of subspace vectors was adequate over the full time interval, although this is not expected to be true for all systems
Differing current and optical return stroke speeds in lightning
No full textDuring the return stroke in downward negative cloud-to-ground lightning, a current wave propagates upward from the ground along the lightning channel. The current wave causes rapid heating of the channel and induces intense optical radiation. The optical radiation wave propagation speed along the channel has been measured to be between 1/5 and 2/3 of the speed of light. The current wave speed is commonly assumed to be the same but cannot be directly measured. Past modeling efforts treat either the thermodynamics or electrodynamics. We present the first model that simultaneously treats the coupled current and thermodynamic physics in the return stroke channel. We utilize numerical simulations using realistic high-temperature air plasma properties that self-consistently solve Maxwell's equations coupled with equations of air plasma thermodynamics. The predicted optical radiation wave speed, rise time, and attenuation agree well with observations. The model predicts significantly higher current return stroke speed
Retrospective evaluation of 83 patients with hairy cell leukemia treated with 3 different treatment modalities in the last two decades: a single center experience
No full textView subspaces for indexing and retrieval of 3D models
No full textView-based indexing schemes for 3D object retrieval are gaining popularity since they provide good retrieval results. These schemes are coherent with the theory that humans recognize objects based on their 2D appearances. The viewbased techniques also allow users to search with various queries such as binary images, range images and even 2D sketches. The previous view-based techniques use classical 2D shape descriptors such as Fourier invariants, Zernike moments, Scale Invariant Feature Transform-based local features and 2D Digital Fourier Transform coefficients. These methods describe each object independent of others. In this work, we explore data driven subspace models, such as Principal Component Analysis, Independent Component Analysis and Nonnegative Matrix Factorization to describe the shape information of the views. We treat the depth images obtained from various points of the view sphere as 2D intensity images and train a subspace to extract the inherent structure of the views within a database. We also show the benefit of categorizing shapes according to their eigenvalue spread. Both the shape categorization and data-driven feature set conjectures are tested on the PSB database and compared with the competitor view-based 3D shape retrieval algorithms
Electrical telegraph
No full textAn electrical telegraph is a telegraph that uses electrical signals, usually conveyed via dedicated telecommunication lines or radio. This one has been used in US Army between 1941-1945. (02.12.2015)This sound was recorded by Zoom H-6 Portable Multitrack Sound Recorder with SGH-6 Shotgun Microphone and edited in Ableton
Daimler DS420 Limousine
No full textThe Daimler limousine DS420, popularly known as theDaimler Limousine, is a large limousine produced byThe Daimler Company Limited between 1968 and 1992. The vehicles are used extensively as official state cars in several countries, including by the British,Danish and Swedish royal houses. The car is also commonly used in the wedding, funeral, and hotel trades. This model was used by Sir Mark Russell, British Ambassador of Turkey from 1983 to 1986 in Ankara. (02.12.2015)This sound was recorded by Zoom H-6 Portable Multitrack Sound Recorder with SGH-6 Shotgun Microphone and edited in Ableton
The tugboat liman 2 steam engine
No full textThe Istanbul Port Company commissioned the Dutch firm Kreber to build the Tugboat Liman 2 in 1935. Liman 2 was used as a general harbour tug, assisting larger ships until 1990. (19.12.2015)This sound was recorded by Zoom H-6 Portable Multitrack Sound Recorder with SGH-6 Shotgun Microphone and edited in Ableton
Ericsson the bakelite telephone rotary dial
No full textThe Bakelite phone, officially known as Ericsson DBH 1001, and later as M33, N1020, and ED 702, was a Swedish line of telephones made from the polymer Bakelite and produced for over thirty years between 1931 and 1962. Until the early 1930s, the housing of the Swedish phone models was made from pressed steel. Material change from steel to Bakelite brought new opportunities in design, while also reducing the production time for the housing. The Bakelite phone was not only compact but also light at just below 3kg, and could be grasped by one hand. (19.12.2015)This sound was recorded by Zoom H-6 Portable Multitrack Sound Recorder with SGH-6 Shotgun Microphone and edited in Ableton
Design, fabrication and characterization of transparent retro-reflective screen
No full textA transparent retro-reflective screen, which can be used as head-up-display (HUD) or a see-through screen for head mounted projection displays (HMPD) is proposed. The high optical gain of screen enables the use of low power projectors to produce very bright content. The screen assembly is based on retro-reflective microspheres, patterned on an optically clear substrate using steel stencil as a shadow mask. The incident light is retro-reflected as a narrow angular cone to create an eyebox for the viewer. The optical gain and transparency of screen is varied by changing the fill factor of the mask. The optical design and fabrication of the screen is presented. The retro-reflective and transmission characteristics of screen are evaluated. The impact of fill factor on screen luminance and transparency is studied. The screen provides high luminance (up to 280cd/m2 with 50% transparency) from about 40cm to >3m when used with a low power (15 lumen) mobile projector. Unlike regular diffusers, luminance remains nearly constant with projection distance. Furthermore, the screen offers prominent see-through capability with small degradation in modulation transfer function for transmitted light. For a particular camera and imaging configuration, MTF10 (10% cutoff) for 50% transparent screen is reduced from 37 cyc/deg to 30 cyc/deg when screen is inserted at an intermediate distance