4,856 research outputs found
Fatal lymphoproliferation and acute monocytic leukemia-like disease following infectious mononucleosis in the elderly
Three elderly patients are reported, in whom serologically confirmed recent infectious mononucleosis is followed by fatal lymphoproliferation (case 1), by acute monocytic leukemia (case 2), and by acute probably monocytic leukemia (case 3)
Study to establish cost projections for production of Redox chemicals
A cost study of four proposed manufacturing processes for redox chemicals for the NASA REDOX Energy Storage System yielded favorable selling prices in the range 1.91/kg of chromic chloride, anhydrous basis, including ferrous chloride. The prices corresponded to specific energy storage costs from under 17/kWh. A refined and expanded cost analysis of the most favored process yielded a price estimate corresponding to a storage cost of $11/kWh. The findings supported the potential economic viability of the NASA REDOX system
Assessment of crash fire hazard of LH sub 2 fueled aircraft
The relative safety of passengers in LH2 - fueled aircraft, as well as the safety of people in areas surrounding a crash scene, has been evaluated in an analytical study. Four representative circumstances were postulated involving a transport aircraft in which varying degrees of severity of damage were sustained. Potential hazard to the passengers and to the surroundings posed by the spilled fuel was evaluated for each circumstance. Corresponding aircraft fueled with liquid methane, Jet A, and JP-4 were also studied in order to make comparisons of the relative safety. The four scenarios which were used to provide a basis for the evaluation included: (1) a small fuel leak internal to the aircraft, (2) a survivable crash in which a significant quantity of fuel is spilled in a radial pattern as a result of impact with a stationary object while taxiing at fairly low speed, (3) a survivable crash in which a significant quantity of fuel is spilled in an axial pattern as a result of impact during landing, and (4) a non-survivable crash in which a massive fuel spill occurs instantaneously
POSITION AND ALIGNMENT OF FLEX ZONES IN RUNNING SHOES
The right position and alignment of forefoot flexibility zones in running shoes represents a precondition to avoid overuse injuries of the foot and leg. The goal of this study was to determine foot anthropometries, in order to set up construction guidelines for the positioning and alignment of the flex zones in running shoes. The foot anthropometries of 471 runners were measured with a 2D scanning system under static conditions. The metatarsal-length-indices (MU) were calculated for each ray. The calculated MUs do not indicate the necessity for a grading pattern regarding different shoe sizes, gender dimorphism and different regions. To consider the anthropometrical variance of the MUs it is suggested to apply flex zones instead of only flex grooves. The results suggest the application of a transversal, a longitudinal and a diagonal flex zone in running shoes
Experimental realization of a quantum game on a one-way quantum computer
We report the first demonstration of a quantum game on an all-optical one-way
quantum computer. Following a recent theoretical proposal we implement a
quantum version of Prisoner's Dilemma, where the quantum circuit is realized by
a 4-qubit box-cluster configuration and the player's local strategies by
measurements performed on the physical qubits of the cluster. This
demonstration underlines the strength and versatility of the one-way model and
we expect that this will trigger further interest in designing quantum
protocols and algorithms to be tested in state-of-the-art cluster resources.Comment: 13 pages, 4 figure
About the dynamics and thermodynamics of trapped ions
This tutorial introduces the dynamics of charged particles in a
radiofrequency trap in a very general manner to point out the differences
between the dynamics in a quadrupole and in a multipole trap. When dense
samples are trapped, the dynamics is modified by the Coulomb repulsion between
ions. To take into account this repulsion, we propose to use a method,
originally developed for particles in Penning trap, that model the ion cloud as
a cold fluid. This method can not reproduce the organisation of cold clouds as
crystals but it allows one to scale the size of large samples with the trapping
parameters and the number of ions trapped, for different linear geometries of
trap.Comment: accepted for publication in the "Modern Applications of Trapped Ions"
special issu
Controlling fast transport of cold trapped ions
We realize fast transport of ions in a segmented micro-structured Paul trap.
The ion is shuttled over a distance of more than 10^4 times its groundstate
wavefunction size during only 5 motional cycles of the trap (280 micro meter in
3.6 micro seconds). Starting from a ground-state-cooled ion, we find an
optimized transport such that the energy increase is as low as 0.10 0.01
motional quanta. In addition, we demonstrate that quantum information stored in
a spin-motion entangled state is preserved throughout the transport. Shuttling
operations are concatenated, as a proof-of-principle for the shuttling-based
architecture to scalable ion trap quantum computing.Comment: 5 pages, 4 figure
Target Zones in History and Theory: Lessons from an Austro-Hungarian Experiment (1896-1914)
The first known experiment with an exchange rate band took place in Austria-
Hungary between 1896 and 1914. The rationale for introducing this policy rested
on precisely those intuitions that the modern literature has emphasized: the band
was designed to secure both exchange rate stability and monetary policy
autonomy. However, unlike more recent experiences, such as the ERM, this
policy was not undermined by credibility problems. The episode provides an ideal
testing ground for some important ideas in modern macroeconomics: specifically,
can formal rules, when faithfully adhered to, provide policy makers with some
advantages such as short term autonomy? First, we find that a credible band has a
"microeconomic" influence on exchange rate stability. By reducing uncertainty, a
credible fluctuation band improves the quality of expectations, a channel that has been neglected in the modern literature. Second, we show that the standard test of the basic target zone model is flawed and develop an alternative methodology. We believe that these findings shed a new light on the economics of exchange rate bands
Towards reliable micromagnetic detection of white etching layers in deep drilled quenched and tempered steels
Ultrafine-grained white etching layers (WEL) can be formed in the machining of steels, titanium alloys and nickel-based superalloys due to high forces and temperatures in the contact area of the tool and the workpiece. In general, these layers are associated with very high hardness and brittleness as well as (tensile) residual stresses. These mechanical properties of WEL can have a severely negative impact on the lifetime and reliability of components. As a result, it is of crucial importance to reliably detect WEL, understand the underlying mechanisms and physical relationships in their formation and finally control their emergence in machining. Currently, WEL are usually detected using destructive metallographic analyses. In recent years, therefore, the applicability of alternative non-destructive methods for the reliable detection of WEL has been increasingly investigated. In this context, methods such as X-ray diffraction, acoustic emission (AE) and eddy current testing were used. The analysis of magnetic Barkhausen noise (MBN) was identified as a particularly suitable method for the detection of WEL in steels with a very high potential for application in production technology.
In this study, MBN analysis is employed for the time-efficient and non-destructive detection of WEL in deep drilled components made of the quenched and tempered steel AISI 4140. It is shown that WEL form in drilling, especially at high cutting speeds and feeds. The use of coated guide pads and cutting edges promotes the formation of WEL. Hardness in the WEL exceeds the hardness of the bulk material up to three times. Specimens with thick WEL can be separated from specimens free of WEL by significantly lower maximum magnetic Barkhausen noise amplitudes
Cross-verification of independent quantum devices
Quantum computers are on the brink of surpassing the capabilities of even the
most powerful classical computers. This naturally raises the question of how
one can trust the results of a quantum computer when they cannot be compared to
classical simulation. Here we present a verification technique that exploits
the principles of measurement-based quantum computation to link quantum
circuits of different input size, depth, and structure. Our approach enables
consistency checks of quantum computations within a device, as well as between
independent devices. We showcase our protocol by applying it to five
state-of-the-art quantum processors, based on four distinct physical
architectures: nuclear magnetic resonance, superconducting circuits, trapped
ions, and photonics, with up to 6 qubits and 200 distinct circuits
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