Random Articles (Page 56)

Have a deep view into what people are curious about.

πŸ”— List Of Adhesive Tapes

πŸ”— Lists πŸ”— Industrial design

The following is a list of adhesive tapes with pressure-sensitive adhesives:

Discussed on

πŸ”— CAR and CDR

πŸ”— Computing/Websites

Discussed on

πŸ”— Voith Schneider Propeller

πŸ”— Ships

The Voith Schneider propeller (VSP), also known as a cycloidal drive is a specialized marine propulsion system (MPS). It is highly maneuverable, being able to change the direction of its thrust almost instantaneously. It is widely used on tugs and ferries.

Discussed on

πŸ”— Jazelle DBX: Allow ARM processors to execute Java bytecode in hardware

πŸ”— Computing πŸ”— Computing/Computer hardware πŸ”— Computing/Software πŸ”— Java

Jazelle DBX (direct bytecode execution) is an extension that allows some ARM processors to execute Java bytecode in hardware as a third execution state alongside the existing ARM and Thumb modes. Jazelle functionality was specified in the ARMv5TEJ architecture and the first processor with Jazelle technology was the ARM926EJ-S. Jazelle is denoted by a "J" appended to the CPU name, except for post-v5 cores where it is required (albeit only in trivial form) for architecture conformance.

Jazelle RCT (Runtime Compilation Target) is a different technology based on ThumbEE mode; it supports ahead-of-time (AOT) and just-in-time (JIT) compilation with Java and other execution environments.

The most prominent use of Jazelle DBX is by manufacturers of mobile phones to increase the execution speed of Java ME games and applications. A Jazelle-aware Java virtual machine (JVM) will attempt to run Java bytecode in hardware, while returning to the software for more complicated, or lesser-used bytecode operations. ARM claims that approximately 95% of bytecode in typical program usage ends up being directly processed in the hardware.

The published specifications are very incomplete, being only sufficient for writing operating system code that can support a JVM that uses Jazelle. The declared intent is that only the JVM software needs to (or is allowed to) depend on the hardware interface details. This tight binding facilitates the hardware and JVM evolving together without affecting other software. In effect, this gives ARM Holdings considerable control over which JVMs are able to exploit Jazelle. It also prevents open source JVMs from using Jazelle. These issues do not apply to the ARMv7 ThumbEE environment, the nominal successor to Jazelle DBX.

Discussed on

πŸ”— The High Cost of Free Parking

πŸ”— Books πŸ”— Urban studies and planning

The High Cost of Free Parking is an urban planning book by UCLA professor Donald Shoup dealing with the costs of free parking on society. It is structured as a criticism of the planning and regulation of parking and recommends that parking be built and allocated according to its fair market value. It incorporates elements of Shoup's Georgist philosophy.

The book was originally published in 2005 by the American Planning Association and the Planners Press. A revised edition was released in 2011 by Routledge.

Discussed on

πŸ”— Quantum Zeno Effect

πŸ”— Physics

The quantum Zeno effect (also known as the Turing paradox) is a feature of quantum-mechanical systems allowing a particle's time evolution to be slowed down by measuring it frequently enough with respect to some chosen measurement setting.

Sometimes this effect is interpreted as "a system cannot change while you are watching it". One can "freeze" the evolution of the system by measuring it frequently enough in its known initial state. The meaning of the term has since expanded, leading to a more technical definition, in which time evolution can be suppressed not only by measurement: the quantum Zeno effect is the suppression of unitary time evolution in quantum systems provided by a variety of sources: measurement, interactions with the environment, stochastic fields, among other factors. As an outgrowth of study of the quantum Zeno effect, it has become clear that applying a series of sufficiently strong and fast pulses with appropriate symmetry can also decouple a system from its decohering environment.

The name comes from Zeno's arrow paradox, which states that because an arrow in flight is not seen to move during any single instant, it cannot possibly be moving at all. The first rigorous and general derivation of the quantum Zeno effect was presented in 1974 by Degasperis, Fonda, and Ghirardi, although it had previously been described by Alan Turing. The comparison with Zeno's paradox is due to a 1977 article by George Sudarshan and Baidyanath Misra.

According to the reduction postulate, each measurement causes the wavefunction to collapse to an eigenstate of the measurement basis. In the context of this effect, an observation can simply be the absorption of a particle, without the need of an observer in any conventional sense. However, there is controversy over the interpretation of the effect, sometimes referred to as the "measurement problem" in traversing the interface between microscopic and macroscopic objects.

Another crucial problem related to the effect is strictly connected to the time–energy indeterminacy relation (part of the indeterminacy principle). If one wants to make the measurement process more and more frequent, one has to correspondingly decrease the time duration of the measurement itself. But the request that the measurement last only a very short time implies that the energy spread of the state in which reduction occurs becomes increasingly large. However, the deviations from the exponential decay law for small times is crucially related to the inverse of the energy spread, so that the region in which the deviations are appreciable shrinks when one makes the measurement process duration shorter and shorter. An explicit evaluation of these two competing requests shows that it is inappropriate, without taking into account this basic fact, to deal with the actual occurrence and emergence of Zeno's effect.

Closely related (and sometimes not distinguished from the quantum Zeno effect) is the watchdog effect, in which the time evolution of a system is affected by its continuous coupling to the environment.

Discussed on

πŸ”— Photoacoustic Effect

The photoacoustic effect or optoacoustic effect is the formation of sound waves following light absorption in a material sample. In order to obtain this effect the light intensity must vary, either periodically (modulated light) or as a single flash (pulsed light). The photoacoustic effect is quantified by measuring the formed sound (pressure changes) with appropriate detectors, such as microphones or piezoelectric sensors. The time variation of the electric output (current or voltage) from these detectors is the photoacoustic signal. These measurements are useful to determine certain properties of the studied sample. For example, in photoacoustic spectroscopy, the photoacoustic signal is used to obtain the actual absorption of light in either opaque or transparent objects. It is useful for substances in extremely low concentrations, because very strong pulses of light from a laser can be used to increase sensitivity and very narrow wavelengths can be used for specificity. Furthermore, photoacoustic measurements serve as a valuable research tool in the study of the heat evolved in photochemical reactions (see: photochemistry), particularly in the study of photosynthesis.

Most generally, electromagnetic radiation of any kind can give rise to a photoacoustic effect. This includes the whole range of electromagnetic frequencies, from gamma radiation and X-rays to microwave and radio. Still, much of the reported research and applications, utilizing the photoacoustic effect, is concerned with the near ultraviolet/visible and infrared spectral regions.

Discussed on

πŸ”— Psychedelics in problem-solving experiment

πŸ”— California πŸ”— California/San Francisco Bay Area πŸ”— Medicine πŸ”— Neuroscience πŸ”— Psychoactive and Recreational Drugs

Psychedelic agents in creative problem-solving experiment was a study designed to evaluate whether the use of a psychedelic substance with supportive setting can lead to improvement of performance in solving professional problems. The altered performance was measured by subjective reports, questionnaires, the obtained solutions for the professional problems and psychometric data using the Purdue Creativity, the Miller Object Visualization, and the Witkins Embedded Figures tests. This experiment was a pilot that was to be followed by control studies as part of exploratory studies on uses for psychedelic drugs, that were interrupted early in 1966 when the Food and Drug Administration declared a moratorium on research with human subjects, as a strategy in combating illicit use.

Discussed on

πŸ”— Assassination of Kim Jong-Nam

πŸ”— Crime πŸ”— Death πŸ”— Korea πŸ”— Korea/North Korea πŸ”— Malaysia

On 13 February 2017, the eldest son of Kim Jong-il and half-brother of Kim Jong-un, Kim Jong-nam, was attacked with the nerve agent VX at Kuala Lumpur International Airport in Malaysia. He had been exiled from North Korea in 2003 and had been living abroad.

Following his visit to the resort island Langkawi, Kim Jong-nam had arrived at terminal 2 sometime before 9:00 a.m. to take a 10:50 a.m. AirAsia flight to Macau. At approximately 9:00 a.m., two women attacked Kim Jong-nam with the VX nerve agent. He died about 15 to 20 minutes later.

The women were identified as Siti Aisyah, an Indonesian and ĐoΓ n Thα»‹ HΖ°Ζ‘ng, a Vietnamese. Both were charged with the murder of Kim Jong-nam. The charges were dropped, although HΖ°Ζ‘ng pled guilty to "voluntarily causing hurt by dangerous weapons or means" and received a sentence of three years and four months. Four North Korean suspects left the airport shortly after the assassination and reached Pyongyang without being arrested. Other North Koreans were arrested but were released without charge.

It is widely believed that Kim Jong-nam was murdered on the orders of Kim Jong-un.

πŸ”— Soviet version of the Space Shuttle

πŸ”— Aviation πŸ”— Soviet Union πŸ”— Russia πŸ”— Russia/technology and engineering in Russia πŸ”— Spaceflight πŸ”— Aviation/aircraft πŸ”— Central Asia

Buran (Russian: Бура́н, IPA:Β [bʊˈran], meaning "Snowstorm" or "Blizzard"; GRAU index serial number: "11F35 K1") was the first spaceplane to be produced as part of the Soviet/Russian Buran programme. It is, depending on the source, also known as "OK-1K1", "Orbiter K1", "OK 1.01" or "Shuttle 1.01". Besides describing the first operational Soviet/Russian shuttle orbiter, "Buran" was also the designation for the entire Soviet/Russian spaceplane project and its orbiters, which were known as "Buran-class spaceplanes".

OK-1K1 completed one uncrewed spaceflight in 1988, and was destroyed in 2002 when the hangar it was stored in collapsed. The Buran-class orbiters used the expendable Energia rocket, a class of super heavy-lift launch vehicle.

Discussed on