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News Article | September 23, 2016
Site: www.techtimes.com

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.


News Article | September 18, 2016
Site: www.gizmag.com

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."


Ucer T.C.,Oaklands Hospital | Botticelli D.,ARDEC | Stavropoulos A.,Malmö University | Mattheos N.,University of Hong Kong
European Journal of Dental Education | Year: 2014

Introduction: Previous surveys have shown that newly graduated dentists, in most European countries, do not obtain adequate theoretical knowledge and, especially, clinical skills in implant dentistry (ID) through their undergraduate education and must therefore acquire knowledge and develop competencies through further postgraduate study. Moreover, clinicians, in general, need to continue to maintain the currency of their competence by undertaking ongoing continuing professional development (CPD). This seems particularly important in ID as techniques, and materials develop rapidly due to advances in biomedical technology. Despite recent developments, CPD in ID remains poorly organised with little standardisation or harmonisation across Europe. The objective of this survey was to explore the current status and trends within CPD education in ID in Europe. Materials and methods: Stakeholders and opinion leaders associated with ID education were invited by email to fill an online questionnaire (closing date: 30th April 2013). Two hundred and forty-seven questionnaires were distributed, and two separate reminders were sent to participants in 38 European countries. The survey contained 14 multiple-choice questions, and the data were collected using SurveyMonkey© software, exported in SPSS (Inc, Chicago, IL, USA) format and analysed using descriptive statistics. Results: Two hundred respondents working in 24 countries replied to the survey (response rate of 81% of invitees and 63% of countries surveyed). The results demonstrated a wide divergence in the content and structure of CPD in ID in Europe. Conclusions: Dentists need CPD to develop their skills and to maintain their competence in ID. There is an urgent need for structured and accredited CPD, which should be readily available to all dentists practising ID. It should have pre-determined learning objectives, delivered by accredited CPD providers and educators, and have assessable outcome measures to ensure the best possible impact on clinical practice and patient safety. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.


Ucer T.C.,Oaklands Hospital | Botticelli D.,ARDEC | Stavropoulos A.,Malmö University | Cowpe J.G.,University of Cardiff
European Journal of Dental Education | Year: 2014

Introduction: Training for dental practitioners in implant dentistry ranges from 1- or 2-day short Continuing Professional Development (CPD) courses to certificate/diploma programmes run by universities. In general, the teaching of implant dentistry in Europe lacks structure and standardisation. This paper aims to: (i) identify the current trends in CPD in implant dentistry in Europe; (ii) identify potential and limitations with regards to the design and implementation of CPD activities in implant dentistry; (iii) provide recommendations on the future structure and development of CPD activities in implant dentistry. Methods: A search of the literature was undertaken in PubMed for manuscripts published in English after 2000 reporting on CPD in dentistry and in implant dentistry in particular. In addition, an electronic survey was conducted, investigating the attitudes towards CPD among a wide group of stakeholders in implant dentistry education. Conclusions: There is a wide diversity of educational pathways towards achieving competences in implant dentistry through CPD. At present, there is a need for improving the CPD structures in implant dentistry, strengthening the quality assurance and encouraging standardisation and transparency of the learning outcomes. Development of a structured CPD system with clearly defined educational objectives mapped against specific levels of competence is recommended. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.


Bressan E.,University of Padua | Bressan E.,University of Ferrara | Ferroni L.,University of Padua | Gardin C.,University of Padua | And 6 more authors.
PLoS ONE | Year: 2012

The aim of the present work is to study how biological properties, such as proliferation and commitment ability, of human adult dental pulp stem cells (DPSCs) relate to the age of the donor. Human dental pulps were extracted from molars of healthy adult subjects aged 16 to >66 years. DPSCs were isolated and cultured in the presence of osteogenic, neurogenic, or vasculogenic differentiation medium. Proliferation ability was evaluated by determining doubling time, and commitment ability was evaluated by gene expression and morphological analyses for tissue-specific markers. The results confirm a well-defined proliferative ability for each donor age group at an early in vitro passage (p2). DPSCs from younger donors (up to 35 years) maintain this ability in long-term cultures (p8). Stem cells of all age donor groups maintain their commitment ability during in vitro culture. In vivo tests on the critical size defect repair process confirmed that DPSCs of all donor ages are a potent tool for bone tissue regeneration when mixed with 3D nanostructured scaffolds. © 2012 Bressan et al.


Rossi F.,University of Bologna | Lang N.P.,University of Hong Kong | De Santis E.,ARDEC | Morelli F.,University of Habana | And 3 more authors.
Clinical Oral Implants Research | Year: 2014

Objective: To study the early sequential stages of osseointegration at implants installed in alveolar bony. Materials and methods: In 12 Labrador dogs, all mandibular premolars and first molars were extracted bilaterally. After 3 months of healing, full-thickness flaps were elevated in the edentulous region of the right side of the mandible. Implants were installed, and the flaps were sutured to allow a fully submerged healing. The timing of the installations in the left side of the mandible and of sacrifices were performed with a schedule that various observation periods to sacrifice from 5, 10, 20, and 30 days were available so that n = 6 was obtained per each healing period. Ground sections were prepared and analyzed. Results: Newly formed bone in contact with the implant surface was found after 10 days of healing and the percentage increased up to 50% after 1 month of healing. A higher percentage was found in the trabecular compared with the cortical bony compartment. Old bone decreased by about 50% during healing, being still present after 1 month (16%). The proportions of bone debris and bone particles were at 27% after 5 days and decreased during healing to 6% after 1 month. Conclusion: Osseointegration (new bone-to-implant contact) developed at various rates for cortical and trabecular compartments, respectively. In the trabecular region, mesenchymal cells were identified, subsequently developing into new bone in contact with the implant surface. In the cortical compartment, however, resorptive processes were observed throughout all periods of healing. The proportion of newly formed bone percentage was lower compared with that of the trabecular area. Old bone was still present after 1 month of healing in both compartments. Bone debris and small bone particles appeared to be involved in initial bone formation. © 2013 John Wiley & Sons A/S.


Scala A.,ARDEC | Lang N.P.,University of Hong Kong | Schweikert M.T.,University of Habana | de Oliveira J.A.,São Paulo State University | And 4 more authors.
Clinical Oral Implants Research | Year: 2014

Aim: To describe the sequential healing of open extraction sockets at which no attempts to obtain a primary closure of the coronal access to the alveolus have been made. Material and methods: The third mandibular premolar was extracted bilaterally in 12 monkeys, and no sutures were applied to close the wound. The healing after 4, 10, 20, 30, 90 and 180 days was morphometrically studied. Results: After 4 days of healing, a blood clot mainly occupied the extraction sockets, with the presence of an inflammatory cells' infiltrate. A void was confined in the central zones of the coronal and middle regions, in continuity with the entrance of the alveoli. At 10 days, the alveolus was occupied by a provisional matrix, with new bone formation lining the socket bony walls. At 20 days, the amount of woven bone was sensibly increasing. At 30 days, the alveolar socket was mainly occupied by mineralized immature bone at different stages of healing. At 90 and 180 days, the amount of mineralized bone decreased and substituted by trabecular bone and bone marrow. Bundle bone decreased from 95.5% at 4 days to 7.6% at 180 days, of the whole length of the inner alveolar surface. Conclusions: Modeling processes start from the lateral and apical walls of the alveolus, leading to the closure of the socket with newly formed bone within a month from extraction. Remodeling processes will follow the previous stages, resulting in trabecular and bone marrow formation and in a corticalization of the socket access. © 2013 John Wiley & Sons A/S. Published by Blackwell Publishing Ltd.


Wiegand D.A.,ARDEC | Redingius B.,ARDEC | Ellis K.,Atomic Weapons Establishment | Leppard C.,Atomic Weapons Establishment
International Journal of Solids and Structures | Year: 2011

The mechanical properties of a polymer composite plastic bonded explosive, EDC37, have been investigated as a function of hydrostatic confining pressure between 0.1 and 138 MPa. The results indicate different failure processes in two pressure ranges, a low pressure range between about 0.1 and 7 MPa and a higher pressure range between about 7 and 138 MPa. In the low pressure range slow crack processes are important in failure while in the higher pressure range plastic flow dominates. The pressure dependence of the compressive strength in the low pressure range is attributed to coulomb friction between surfaces of closed shear cracks and from the observed linear increase of the strength with pressure and the angle of the fracture plane a friction coefficient is obtained. Friction coefficients can also be obtained from the ratio of the compressive to tensile strength and directly from the above angle. The friction coefficients obtained from these separate observations are in agreement and this is taken as strong evidence for the importance of this friction in determining strength and mechanical failure. These results clearly establish experimentally the role of friction in determining strength with or without applied pressure. An empirical relationship between strength, pressure and strain rate is also obtained for this pressure range and the failure strength of EDC37 is more sensitive to pressure than strain rate. © 2011 Elsevier Ltd. All rights reserved.


Macri M.F.,ARDEC | Littlefield A.G.,ARDEC
International SAMPE Technical Conference | Year: 2015

Fielded and future military systems are increasingly incorporating composite materials into their design. Many of these systems subject the composites to physical trauma or environmental conditions that can cause micro damage leading to variations of the mechanical properties on the global scale. For these applications, it is critical to develop the ability to accurately model the response of composite materials, to enable engineers to predict the reaction of the system. To address this problem, a structural based enrichment approach is proposed, that allows macro-scale computations to be performed with the micro-structural features explicitly considered. This strategy has an advantage in that the enriched local function space may be easily varied from one element to the other allowing variances in the microstructure, such as localized damage to the fibers. Copyright 2015. Used by the Society of the Advancement of Material and Process Engineering with permission.


Macri M.F.,ARDEC | Littlefield A.G.,ARDEC
International SAMPE Technical Conference | Year: 2016

Fielded and future military systems are increasingly incorporating composite materials into their design. Many of these systems subject the composites to physical trauma or environmental conditions that can cause micro damage leading to variations of the mechanical properties on the global scale and global sized fracture. Though several multiscale methods have been developed to account for the micro effects, little has been done to efficiently incorporate them into a finite element model, limiting their effectiveness. To contend with this issue, an algorithm has been developed to detect elements within a critical region and apply a partition of unity multiscale approach to capture the micro phenomena. Thus, in critical regions of the model, a multiscale approach can be implemented to accurately capture the material response, and throughout the rest of the model the efficient homogenization method will be employed. The elements surrounding the critical region are adapted to act as a transition from the multiscale region to the homogenization region.

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