Zhang Z.,University of California at Davis |
Topping T.,University of California at Davis |
Li Y.,University of California at Davis |
Vogt R.,University of California at Davis |
And 6 more authors.
Scripta Materialia | Year: 2011
The influence of nanoscale reinforcement on the mechanical behavior of ultrafine-grained composites was studied. Al 5083 (Al-4.5 Mg-0.57Mn-0.25Fe) composites, with grain size of 115 nm and B4C reinforcement size of 38 nm, were fabricated via cryomilling and consolidation. The result reveals that the presence of nanoparticles enhances strength by interacting with dislocations, while simultaneously retarding grain growth. Furthermore, the nanoparticles-reinforced composite exhibits enhanced plasticity relative to the same material reinforced with micrometric particles. The underlying mechanisms are discussed. © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
News Article | February 24, 2017
Young rebel fighters in civil war-stricken Syria are using Snapchat as their social media platform of choice for selling, buying, and boasting about weapons and equipment for the battlefield. Snapchat messages received by Motherboard itself, as well as screenshots provided to Motherboard of accounts posting items such as consumer drones and thermal scopes for sale, show that the ephemeral messaging app provides the perfect mix of instantaneous and direct storytelling for a mobile-only, millennial generation of fighters. Snapchat, which this week expanded sales of its Spectacles eyewear device to the general public, is most popular amongst 18 to 24-year-olds in the US. The story, Motherboard is told, is no different in Syria. "For the most part, rebel fighters use Snapchat like kids in the West," John Arterbury, a Washington DC-based security analyst, told Motherboard in an email. "They show off what they're doing, they document light-hearted moments, and they cultivate and project a stylized image of themselves. When they do use it as a weapons market, it's to showcase items that maybe aren't normally found in the real-world arms markets of Idlib and its surroundings." Arterbury showed Motherboard two documented cases of items put up for sale over Snapchat in the past couple of months. The first item was a Phantom 4 consumer drone, with the seller noting it had been used to film a Jabhat al-Nusra battle scene. Another instance, this one of an actual arms sales listing, pertained a thermal riflescope, which was being sold to raise funds for Haya-at Tahrir al-Sham, a Jihadist and Salafist group involved in the Syrian Civil War. "I've also seen them sell expensive falcons [live birds] on Snapchat. Again, since Snapchat is mostly used for friends to communicate with friends, this is maybe a way to show your friends that you've got something exceptional to sell and hope it spreads by word of mouth," Arterbury told Motherboard. Motherboard also spoke with a weapons tracker on Twitter who had previously documented cases of weapons for sale over Snapchat. @LostWeapons told Motherboard via Twitter DM, "I actually just follow YouTube accounts that upload rebel Snapchats, not as awkward Screenshotting it." LostWeapons sent Motherboard the URL of a YouTube account that was uploading the Snapchat stories of rebels in Syria. The Snapchat stories included weapons for sale and images of heavier weapons such as shells and mortars. Motherboard's own foray into weapons sales on Snapchat yielded instant results. We created a dummy account under a pseudonym without any images, and passively followed accounts of purported Syrian rebels. Several were sending out Snapchat stories that included calls for donations for weapon accessories, including a thermal optic riflescope. "Thermal sight for Mujahideen (those involved in Jihad), you can connect via this id on Telegram @ash551," the message above reads. Another Snapchat story (below) is a call for donations for thermal binoculars. "A lot of these Snapchat ones are 'asking for donations to buy the weapons' too," LostWeapons told Motherboard. Further Snapchat stories from account associated with the sale of weapons and weapon accessories, seen by Motherboard, contain montages of Syrian rebel snipers taking down unidentified targets and other war propaganda. "It's one of the many platforms we've seen being used," said N.R. Jenzen-Jones, director of Armament Research Services (ARES), regarding Snapchat. "We've documented either advertisements or direct sales via a pretty wide range of social media and messaging apps. Facebook, Twitter DMs, Instagram, Snapchat, Kik, Whatsapp, and Telegram, among others. Motherboard contacted Snapchat for comment on this story. A Snapchat representative flagged the company's Trust and Safety guidelines and terms of service, and said it will investigate and take appropriate action. Indeed, even with Snapchat's apparent popularity amongst young fighters, Arterbury said most arms probably occur off the platform, thanks to the overall proliferation of small arms in Syria. "It's not difficult to purchase guns or ammo in rebel-held northern Syria," he said. Arterbury pointed to the ongoing private sales of arms on Facebook, too, a practice that Facebook itself vowed to clamp down on in 2016. However, an April 2016 report by the Small Arms Survey, using research conducted by Armament Research Services, highlighted the problem of weapons sales via social media channel such as Facebook still exists. Another report examining arms sales via social media in Libya, which Jenzen-Jones co-authored, is being released by the Small Arms Survey in the coming weeks. "When it comes to digital sales, I presume that lots of arms brokers use WhatsApp. While I've seen no direct evidence of this, WhatsApp is used for all sorts of commercial endeavors in Idlib—from cars to diesel to celebratory sheep for Eid—that I assume it extends to weapons," Arterbury told Motherboard. He also added that to his knowledge, Facebook arms markets based out of Iraq are still in operation. Arterbury did provide Motherboard with examples of weapon sales adverts from a Facebook-hosted Idlib arms market in Syria. I think part of it, with Facebook for example, is we tend to see broader, kind of classified-style advertisements, where people put up a picture and say 'look, here's what I'm selling, here's what I want for it'. Platforms like Snapchat, and some of the other direct messaging apps, tend to be, in our experience so far, more follow ups. So that might be someone responding to somebody, and using Snapchat as a purportedly discreet way to exchange more details including serial numbers and other details. LostWeapons also told Motherboard, "People say Facebook is still #1 for weapons. A few articles came out last year and [Facebook] cracked down on it for a few days but nothing's changed. Facebook told Motherboard in an email this week, "The purchase/sale of firearms is not allowed on Facebook," adding that its community standards also prohibit the sale of firearms. Instead, while arms sales have almost certainly occurred via Snapchat, it's clear the app is being used more successfully to boast, show off, and send propaganda. And to that that end, Snapchat is the perfect platform. It's quick, users have complete control over who is seeing their messages, and most importantly, it provides a mobile-first means of communication amongst friends on the frontline.
News Article | September 23, 2016
Engineers at the U.S. Army Armament Research, Development and Engineering Center (ARDEC) are designing a next-generation hand grenade, which will have two deadly modes and could offer more flexibility to U.S. soldiers. The U.S. military uses two types of grenades: fragmentation and concussion models. A fragmentation grenade explodes and it releases shrapnel and ball bearing that hits enemy combatants. Fragmentation grenades have a radius of about 49 feet. A concussion grenade results in a powerful blast that can incapacitate or kill. However, these grenades have a smaller radius, which means soldiers have to use them in close proximity. The hand grenade being developed by ARDEC is known as Enhanced Tactical Multi-Purpose, or ET-MP. This new device can combine the fragmentation and concussion models in one single grenade. Soldiers in war zones will be able to switch between modes from fragmentation to concussion or vice versa by flipping a lever in the grenade. Currently, soldiers in the U.S. army carry one M67 fragmentation grenade. In 1975, the military took the MK3A2 concussion grenade out of service because of asbestos hazard. ARDEC is also implementing some design changes to the ET-MP. Current fragmentation grenades require different arming procedures for right-handed and left-handed users. However, the next-gen ET-MP is ambidextrous and arming procedure is same for left-hand or right-hand users. The ET-MP will be fully electronic, which will result in greater precision and reliability of the grenade. "With these upgrades in the ET-MP, not only is the fuze timing completely electronic, but the detonation train is also out-of-line," says Matthew Hall, a development lead on the project. "Detonation time can now be narrowed down into milliseconds." Hall added that the new ET-MP grenade will not explode until it is armed by a soldier. Reports suggest that existing grenades have hardly seen any design changes in the last four decades. The need for a fresh hand grenade was made in 2010 while funding for the research of a new grenade got approved a few years later in 2013. Since then, engineers have worked together with Marines and soldiers on duty to understand the needs of a new grenade. Engineers have determined the requirement of a new grenade and the idea of ET-MP was born. By 2020, ARDEC is estimated to move the ET-MP to the following development stage at the Project Manager Close Combat Systems located at Picatinny Arsenal. The U.S. military will have to wait another few years before the ET-MP can be used in combat. © 2017 Tech Times, All rights reserved. Do not reproduce without permission.
Sadangi R.,Armament Research |
Bose A.,Materials Processing Inc.
Advances in Powder Metallurgy and Particulate Materials - Proceedings of the 2015 International Conference on Powder Metallurgy and Particulate Materials, PowderMet 2015 | Year: 2015
Cemented carbide is a classic two-phase composite material where the hard tungsten carbide grains are dispersed in cobalt that contains small amount of tungsten and carbon in solution. They are routinely manufactured via liquid phase sintering of green bodies to full density through a process of rearrangement and solution-reprecipitation. Current trend in the carbide industry is to exploit the benefits of ultrafine-grained hard materials. Ultrafine grained hardmetals are typically prone to excessive grain coarsening during sintering. Grain growth inhibitors in the form of carbides are invariably used to restrict the tungsten carbide grain growth. This paper will review the importance of uniform distribution of inhibitors in restricting the carbide grain growth. To aid in the understanding the role of grain growth inhibitors in hardmetals, a brief discussion on the consolidation of ultrafine grained carbides will be described in the paper.
Sadangi R.,Armament Research |
Bose A.,Materials Processing Inc.
Advances in Tungsten, Refractory and Hardmaterials IX - Proceedings of the 9th International Conference on Tungsten, Refractory and Hardmaterials | Year: 2014
Cobalt has been the binder metal-of-choice for tungsten carbide based hard metals since their inception. Lately, there has been concern about availability, price instability and health-related effects of cobalt. A number of research groups have investigated alternates for full or partial substitution of cobalt by various metals and/or their combinations. Some of the alternate binder elements that have been investigated are nickel, iron, and to some extent chromium. Improvements in fracture toughness, wear and corrosion resistance have been realized using alternate binders. This paper will summarize some of the developments of these new binder alloy compositions.
Bogdanowicz Z.R.,Armament Research
IEEE Transactions on Systems, Man, and Cybernetics: Systems | Year: 2012
Effect-based weapon-target pairing assigns weapons to targets for the given desired effects on such targets. The most obvious and natural effects on targets are represented by the percentages of damage of these targets. In this paper, we focus on the generation of input for effect-based weapon-target pairing optimization. One way to generate such input is based on the Joint Munition Effectiveness Manual (JMEM). JMEM allows the evaluation of the weapons. It is a database that contains many tables, and each table contains many different data fields. Because of the sheer size of JMEM, the optimization of weapon-target pairing based on JMEM is currently focused mainly on one target at a time. In other words, the optimization of weapon-target pairing for many targets and weapons is not directly supported by JMEM, although all the necessary data is there. In this paper, we derive an input based on the given JMEM and desired effect(s), which should be useful in the follow-on effect-based weapon-target pairing optimization that is not limited to a single weapon or target. In particular, effect-based weapon-target pairing will rely on the scanning of the attack guidance table that we derive from JMEM to determine a preferred set of weapon combinations for engaging a given set of targets. © 2006 IEEE.
Rastegar J.,Omnitek Partners, LLC |
Pereira C.M.,Armament Research |
Feng D.,Omnitek Partners, LLC
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2016
Reserve power sources are used extensively in munitions and other devices such as emergency devices or remote sensors that have to be powered only once and for a relatively short duration. Current chemical reserve power sources, including thermal batteries and liquid reserve batteries require sometimes in excess of 100 msec to become fully activated. In many applications, however, electrical energy is required in a few msec following the launch event. In such applications, other power sources have to be provided to provide power until the reserve battery is fully activated. The amount of electrical energy that is required by most munitions before chemical reserve batteries are fully activated is generally small and can be provided by properly designed piezoelectric-based energy harvesting devices. In this paper the development of a hybrid reserve power source obtained by the integration of a piezoelectric-based energy harvesting device with a reserve battery that can provide power almost instantaneously upon munitions firing or other similar events is being reported. A review of the state of the art in piezoelectric-based electrical energy harvesting methods and devices and their charge collection electronics for use in the developed hybrid power sources is also provided together with the results of testing of the piezoelectric component of the power source and its electronic safety and charge collection electronics. © 2016 SPIE.
Kaniyantethu S.,Armament Research
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2011
This paper discusses the many features and composed technologies in Firestorm™ - a Distributed Collaborative Fires and Effects software. Modern response management systems capitalize on the capabilities of a plethora of sensors and its output for situational awareness. Firestorm utilizes a unique networked lethality approach by integrating unmanned air and ground vehicles to provide target handoff and sharing of data between humans and sensors. The system employs Bayesian networks for track management of sensor data, and distributed auction algorithms for allocating targets and delivering the right effect without information overload to the Warfighter. Firestorm Networked Effects Component provides joint weapon-target pairing, attack guidance, target selection standards, and other fires and effects components. Moreover, the open and modular architecture allows for easy integration with new data sources. Versatility and adaptability of the application enable it to devise and dispense a suitable response to a wide variety of scenarios. Recently, this application was used for detecting and countering a vehicle intruder with the help of radio frequency spotter sensor, command driven cameras, remote weapon system, portable vehicle arresting barrier, and an unmanned aerial vehicle - which confirmed the presence of the intruder, as well as provided lethal/non-lethal response and battle damage assessment. The completed demonstrations have proved Firestorm's™ validity and feasibility to predict, detect, neutralize, and protect key assets and/or area against a variety of possible threats. The sensors and responding assets can be deployed with numerous configurations to cover the various terrain and environmental conditions, and can be integrated to a number of platforms. © 2011 SPIE.
News Article | November 29, 2016
France issued an internal note to its security forces last week warning that "this threat is to be taken into account nationwide" and ordering any drone be treated as a "suspicious package". The first record of a deadly IS drone attack was in October when two Iraqi Kurdish fighters were killed and two French special forces soldiers wounded. The device had been booby-trapped and did its damage on the ground when forces approached it after it landed. "The use of drones by terrorist and insurgent forces is a growing issue of international concern," James Bevan, executive director of the Conflict Armament Research NGO, wrote in a recent report. Western countries have seen an unprecedented wave of attacks perpetrated or inspired by IS and the new airborne threat is giving chills to security agencies. "It's a threat we're looking into, especially with all those who will return from Iraq and Syria with bags of battle experience," a French government official told AFP. Some countries, especially those with large numbers of nationals among IS's foreign fighter contingent such as France or Belgium, worry that attacks on home soil will spike after the collapse of the jihadists' "caliphate". Drones are ubiquitous on the front lines of the battle for IS bastion Mosul, which Iraqi forces launched on October 17. The jihadists have used them for some time for reconnaissance missions, just like government forces have, but they have more recently tried to modify them. In mid-November an AFP team on Mosul's southern front saw a small commercial drone, of the kind that will fly off the shelves in the runup to Christmas, drop a grenade on a federal police position. Forces battling their way to the outskirts of Mosul have reported several similar incidents. "They are also using drones in this area," Abu Mohammed al-Atabi, a commander with the Hashed al-Shaabi paramilitaries deployed southwest of Mosul told AFP last week. A high-ranking army officer posted on the southern front said his soldiers were attacked by a modified Phantom 4, a basic camera-fitted "quadcopter" that can be purchased online for less than $1,000. Experts argue that, compared to the suicide car and truck bombs IS sometimes fills with several tonnes of explosives, drones represent a minor threat. Their autonomy is limited and they cannot carry heavy payloads. Yet there is evidence that IS weapons experts have been busy trying to perfect their drones. Conflict Armament Research in February saw a workshop abandoned by IS after Iraqi forces retook the city of Ramadi. The group documented an unmanned aerial vehicle which IS had designed itself, using polystyrene foam and model aircraft components, and fitted with a camera. It said evidence in the workshop also showed attempts to build much larger drones from scratch. "No terrorist entity to date has demonstrated UAS (unmanned aircraft systems) capability that would be considered highly capable, highly lethal and highly secure," Don Rassler, from the Combating Terrorism Center, said in an October report. He warned that could soon change, however. "Future off-the-shelf drones will be able to carry heavier payloads, fly and loiter longer, venture farther from their controller and be able to do so via more secure communications links," he said. The disaster scenario is one in which IS uses drones to disseminate the kind of chemicals it has so far used with limited success on rockets. "Although technically much more difficult to achieve, aerosol or spraying devices can also be attached to a UAS to distribute chemical and biological agents," Rassler said. To counter this new threat, some Western countries have started developing defence systems capable of spotting, tracking and destroying drones. The US military is using kinetic anti-drone systems that physically take on the devices, while others favour hacking or scrambling. Another more unusual technique developed in France uses eagles that are trained—by being fed meat on drones—to spot the aircraft and take them down. "They are capable of detecting them from thousands of metres (yards) away and neutralising them," French air force general Jean-Christophe Zimmermann said. Explore further: 'Dronejacking' may be the next big cyber threat
News Article | September 18, 2016
The ET-MP is the first lethal hand grenade developed for the US Army in 40 years(Credit: US Army) The US military is getting its first new hand grenade in 40 years as engineers at the US Army Armament Research, Development, and Engineering Center (ARDEC) at Picatinny Arsenal, New Jersey, work on a safer multi-purpose design. Called the Enhanced Tactical Multi-Purpose (ET-MP) hand grenade, it will allow soldiers to choose between concussive or fragmentation blasts with the flip of a lever. Though many people think of grenades as little green pineapples with pins sticking out of them, there are actually many different types for many different jobs. There are incendiary grenades for destroying equipment, gas grenades for crowd control, smoke grenades, stun grenades, anti-tank grenades, and even illumination grenades to cast a bit of light on the subject. Concussion grenades are listed as "offensive" because they kill by means of blast. They have a small danger radius, so soldiers can use them while advancing in the open without fear of being caught in the blast wave. Fragmentation grenades, on the other hand, are "defensive." In addition to a high-explosive charge, the fragmentation grenade has a sleeve filled with ball bearings or is wrapped in wire or a metal casing that shatters into lethal bits on detonation. These typically have a danger radius of 15 m (49 ft), so soldiers have to be behind cover when using them. According to the Army, the US inventory of lethal grenades has consisted solely of the M67 fragmentation grenade and its variants since 1975. In that year, the MK3A2 concussion grenade was withdrawn from service – ironically, because of an asbestos hazard. The ET-MP is aimed at replacing both fragmentation and concussion grenades with a safer, more flexible design. At the flip of a lever, the ET-MP changes from one mode to the other, reducing the need for troops to carry multiple grenades, yet having the one to suit the current situation. ARDEC says that the ET-MP is the result of five years development based on requests and feedback from troops wanting an improved grenade, as well as input from Infantry School representatives. Aside from its dual mode, it's also the first US ambidextrous grenade. Previous hand grenades were designed for right handers, which made it difficult for southpaws to use without special instruction. "We received direct input from the Army and Marine Corps early on, which was critical in ensuring the new arming and fuzing design was user friendly," says Matthew Hall, Grenades Tech Base Development Lead. "With these upgrades in the ET-MP, not only is the fuze timing completely electronic, but the detonation train is also out-of-line. Detonation time can now be narrowed down into milliseconds, and until armed, the hand grenade will not be able to detonate."