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🔗 Physics 🔗 Physics/Acoustics

Thermoacoustic engines (sometimes called "TA engines") are thermoacoustic devices which use high-amplitude sound waves to pump heat from one place to another (this requires work, which is provided by the loudspeaker) or use a heat difference to produce work in the form of sound waves (these waves can then be converted into electrical current the same way as a microphone does).

These devices can be designed to use either standing wave or travelling wave.

Compared to vapor refrigerators, thermoacoustic refrigerators have no coolant and few moving parts (only the loudspeaker), therefore require no dynamic sealing or lubrication.

🔗 Computing

The MicroVAX 78032 (otherwise known as the DC333) is a microprocessor developed and fabricated by Digital Equipment Corporation (DEC) that implemented a subset of the VAX instruction set architecture (ISA). The 78032 was used exclusively in DEC's VAX-based systems, starting with the MicroVAX II in 1985. When clocked at a frequency of 5 MHz, the 78032's integer performance is comparable to the original VAX-11/780 of 1977. The microprocessor could be paired with the MicroVAX 78132 floating point accelerator for improved floating point performance.

The 78032 represented a number of firsts for DEC. It was DEC's first single-chip microprocessor implementation of the VAX ISA and DEC's first self-fabricated microprocessor. The MicroVAX 78032 is also notable as it was the first semiconductor device to be registered for protection under the Semiconductor Chip Protection Act of 1984.

The MicroVAX 78032 contains 125,000 transistors on an 8.7 by 8.6 mm (74.82 mm²) die that was fabricated in DEC's ZMOS process, a 3.0 µm NMOS logic process with two layers of aluminum interconnect. The die is packaged in a 68-pin surface-mounted leaded chip carrier.

🔗 Chess

Zugzwang (German for "compulsion to move", pronounced [ˈtsuːktsvaŋ]) is a situation found in chess and other turn-based games wherein one player is put at a disadvantage because they must make a move when they would prefer to pass and not move. The fact that the player is compelled to move means that their position will become significantly weaker. A player is said to be "in zugzwang" when any possible move will worsen their position.

Although the term is used less precisely in games such as chess, it is used specifically in combinatorial game theory to denote a move that directly changes the outcome of the game from a win to a loss. Putting the opponent in zugzwang is a common way to help the superior side win a game, and in some cases it is necessary in order to make the win possible.

The term zugzwang was used in German chess literature in 1858 or earlier, and the first known use of the term in English was by World Champion Emanuel Lasker in 1905. The concept of zugzwang was known to chess players many centuries before the term was coined, appearing in an endgame study published in 1604 by Alessandro Salvio, one of the first writers on the game, and in shatranj studies dating back to the early 9th century, over 1000 years before the first known use of the term.

Positions with zugzwang occur fairly often in chess endgames, especially in king and pawn endgames. According to John Nunn, positions of reciprocal zugzwang are surprisingly important in the analysis of endgames.

🔗 History 🔗 East Asia 🔗 Middle Ages 🔗 Middle Ages/History 🔗 Mongols

The Pax Mongolica (Latin for "Mongol Peace"), less often known as Pax Tatarica ("Tatar Peace"), is a historiographical term modelled after the original phrase Pax Romana which describes the stabilizing effects of the conquests of the Mongol Empire on the social, cultural and economic life of the inhabitants of the vast Eurasian territory that the Mongols conquered in the 13th and 14th centuries. The term is used to describe the eased communication and commerce the unified administration helped to create and the period of relative peace that followed the Mongols' vast conquests.

The conquests of Genghis Khan (r. 1206–1227) and his successors, spanning from Southeast Asia to Eastern Europe, effectively connected the Eastern world with the Western world. The Silk Road, connecting trade centres across Asia and Europe, came under the sole rule of the Mongol Empire. It was commonly said that "a maiden bearing a nugget of gold on her head could wander safely throughout the realm". Despite the political fragmentation of the Mongol Empire into four khanates (Yuan dynasty, Golden Horde, Chagatai Khanate and Ilkhanate), nearly a century of conquest and civil war was followed by relative stability in the early 14th century. The end of the Pax Mongolica was marked by the disintegration of the khanates and the outbreak of the Black Death in Asia which spread along trade routes to much of the world in the mid-14th century.

During this time, Mongol elements including the ʼPhags-pa script made numerous appearances in western art (see Mongol elements in Western medieval art).

🔗 United States/U.S. Government 🔗 United States

The Kyl–Bingaman Amendment (Public Law 104-201, Section 1064) is a United States law. It was put into force by the Military Defense National Defense Authorization Act for 1997.

The Kyl–Bingaman Amendment (KBA) prohibits US authorities from granting a license for collecting or disseminating high resolution satellite imagery of Israel at a higher resolution than is available from other commercial sources, that is, from companies outside of the United States. An exception exists if this is done by a US federal agency, or if it is done in order to abolish the secrecy of such recordings.

U.S. law mandates U.S. government censorship of American commercial satellite images of no country in the world besides that of Israel. The largest and most important global sources of commercial satellite imagery, such as Maxar Technologies, Capella, and Umbra, and the largest and widely-used online resources, such as Google and Bing, are American and this makes KBA a powerful instrument of U.S. government suppression of information. For example, as a result of KBA, images on internet platforms such as Google Earth have been deliberately blurred.

🔗 Physics 🔗 Physics/Publications

"There's Plenty of Room at the Bottom: An Invitation to Enter a New Field of Physics" was a lecture given by physicist Richard Feynman at the annual American Physical Society meeting at Caltech on December 29, 1959. Feynman considered the possibility of direct manipulation of individual atoms as a more powerful form of synthetic chemistry than those used at the time. Although versions of the talk were reprinted in a few popular magazines, it went largely unnoticed and did not inspire the conceptual beginnings of the field. Beginning in the 1980s, nanotechnology advocates cited it to establish the scientific credibility of their work.

🔗 Computing 🔗 Computing/Computer hardware

ESP32 is a family of low-cost, energy-efficient microcontrollers that integrate both Wi-Fi and Bluetooth capabilities. These chips feature a variety of processing options, including the Tensilica Xtensa LX6 microprocessor available in both dual-core and single-core variants, the Xtensa LX7 dual-core processor, or a RISC-V microprocessor. In addition, the ESP32 incorporates components essential for wireless data communication such as built-in antenna switches, an RF balun, power amplifiers, low-noise receivers, filters, and power-management modules.

Typically, the ESP32 is embedded on device-specific printed circuit boards or offered as part of development kits that include a variety of GPIO pins and connectors, with configurations varying by model and manufacturer. The ESP32 was designed by Espressif Systems and is manufactured by TSMC using their 40 nm process. It is a successor to the ESP8266 microcontroller.

🔗 Computer Security 🔗 Computer Security/Computing 🔗 Cryptography 🔗 Cryptography/Computer science

In computer security, a cold boot attack (or to a lesser extent, a platform reset attack) is a type of side channel attack in which an attacker with physical access to a computer performs a memory dump of a computer's random access memory by performing a hard reset of the target machine. Typically, cold boot attacks are used to retrieve encryption keys from a running operating system for malicious or criminal investigative reasons. The attack relies on the data remanence property of DRAM and SRAM to retrieve memory contents that remain readable in the seconds to minutes after power has been removed.

An attacker with physical access to a running computer typically executes a cold boot attack by cold-booting the machine and booting a lightweight operating system from a removable disk to dump the contents of pre-boot physical memory to a file. An attacker is then free to analyze the data dumped from memory to find sensitive data, such as the keys, using various forms of key finding attacks. Since cold boot attacks target random access memory, full disk encryption schemes, even with a trusted platform module installed are ineffective against this kind of attack. This is because the problem is fundamentally a hardware (insecure memory) and not a software issue. However, malicious access can be prevented by limiting physical access and using modern techniques to avoid storing sensitive data in random access memory.

🔗 Volcanoes 🔗 Disaster management 🔗 Geology 🔗 Indonesia

The Toba supereruption was a supervolcanic eruption that occurred about 75,000 years ago at the site of present-day Lake Toba in Sumatra, Indonesia. It is one of the Earth's largest known eruptions. The Toba catastrophe theory holds that this event caused a global volcanic winter of six to ten years and possibly a 1,000-year-long cooling episode.

In 1993, science journalist Ann Gibbons posited that a population bottleneck occurred in human evolution about 70,000 years ago, and she suggested that this was caused by the eruption. Geologist Michael R. Rampino of New York University and volcanologist Stephen Self of the University of Hawaii at Manoa support her suggestion. In 1998, the bottleneck theory was further developed by anthropologist Stanley H. Ambrose of the University of Illinois at Urbana–Champaign. Both the link and global winter theories are controversial. The Toba event is the most closely studied supereruption.

🔗 Computing

A Machine Identification Code (MIC), also known as printer steganography, yellow dots, tracking dots or secret dots, is a digital watermark which certain color laser printers and copiers leave on every single printed page, allowing identification of the device with which a document was printed and giving clues to the originator. Developed by Xerox and Canon in the mid-1980s, its existence became public only in 2004. In 2018, scientists developed privacy software to anonymize prints in order to support whistleblowers publishing their work.