Improving winter traction for vehicles in northern operations

2021 ◽  
Author(s):  
Sally Shoop ◽  
Clifford Witte ◽  
Sebastian Karwaczynski ◽  
Clifton Ellis ◽  
Eoghan Matthews ◽  
...  

As part of the campaign to increase readiness in northern regions, a near commercial off-the-shelf (COTS) solution was identified for the High Mobility Multipurpose Wheeled Vehicle (HMMWV); and used to assess the suitability of commercially available winter tires for operational deployment. Initial performance evaluations conducted during the winters of 2020 and 2021 demonstrated and quantified significant improvements to traction and handling on a variety of winter surfaces. User feedback from United States Army Alaska (USARAK) Soldiers confirmed these results in an operational environment. Results of this study provide new winter tire specifications for the Army and justify the procurement of a HMMWV winter tire for improved safety and capability for US Soldier and vehicle fleet needs. The data and Soldier evaluations support attaining a National Stock Number (NSN) and provide data to develop models of winter vehicle performance that include the impact of winter tires and chains. This work also paves the way for future development and procurement of winter tires for vehicles where COTS solutions are unavailable. The motivation is to provide Soldiers with state-of-the-art winter tires to increase safety, capability, and operational compatibility with North Atlantic Treaty Organization (NATO) partners in the European Theater of Operations, and mobility superiority in all environments.

Author(s):  
Robert H. Ellison

Prompted by the convulsions of the late eighteenth century and inspired by the expansion of evangelicalism across the North Atlantic world, Protestant Dissenters from the 1790s eagerly subscribed to a millennial vision of a world transformed through missionary activism and religious revival. Voluntary societies proliferated in the early nineteenth century to spread the gospel and transform society at home and overseas. In doing so, they engaged many thousands of converts who felt the call to share their experience of personal conversion with others. Though social respectability and business methods became a notable feature of Victorian Nonconformity, the religious populism of the earlier period did not disappear and religious revival remained a key component of Dissenting experience. The impact of this revitalization was mixed. On the one hand, growth was not sustained in the long term and, to some extent, involvement in interdenominational activity undermined denominational identity; on the other hand, Nonconformists gained a social and political prominence they had not enjoyed since the middle of the seventeenth century and their efforts laid the basis for the twentieth-century explosion of evangelicalism in Africa, Asia, and South America.


2016 ◽  
Vol 29 (3) ◽  
pp. 941-962 ◽  
Author(s):  
Thomas L. Delworth ◽  
Fanrong Zeng

Abstract The impact of the North Atlantic Oscillation (NAO) on the Atlantic meridional overturning circulation (AMOC) and large-scale climate is assessed using simulations with three different climate models. Perturbation experiments are conducted in which a pattern of anomalous heat flux corresponding to the NAO is added to the model ocean. Differences between the perturbation experiments and a control illustrate how the model ocean and climate system respond to the NAO. A positive phase of the NAO strengthens the AMOC by extracting heat from the subpolar gyre, thereby increasing deep-water formation, horizontal density gradients, and the AMOC. The flux forcings have the spatial structure of the observed NAO, but the amplitude of the forcing varies in time with distinct periods varying from 2 to 100 yr. The response of the AMOC to NAO variations is small at short time scales but increases up to the dominant time scale of internal AMOC variability (20–30 yr for the models used). The amplitude of the AMOC response, as well as associated oceanic heat transport, is approximately constant as the time scale of the forcing is increased further. In contrast, the response of other properties, such as hemispheric temperature or Arctic sea ice, continues to increase as the time scale of the forcing becomes progressively longer. The larger response is associated with the time integral of the anomalous oceanic heat transport at longer time scales, combined with an increased impact of radiative feedback processes. It is shown that NAO fluctuations, similar in amplitude to those observed over the last century, can modulate hemispheric temperature by several tenths of a degree.


2021 ◽  
Vol 7 (2) ◽  
pp. 142-167
Author(s):  
Catherine E. Travis ◽  
Inas Ghina

Abstract We examine variation in a rural variety of Acehnese spoken in Aceh Province, to better understand the impact of long-term contact with Indonesian and increasing urbanization. The Great Aceh variety is characterized by variable realization of word-final (t) as a dental vs. glottal stop. Analyses of over 2,000 tokens of this variable from a corpus of spontaneous speech from 35 speakers indicate that the variability is relatively stable among men, and among women of high mobility, measured in terms of education, occupation, and time spent outside Great Aceh. Women with low mobility produce the lowest rates of [t̪], and in this group we observe a higher rate of [t̪] by younger than older women, suggesting change over time. We thus find both stability – among those who have long enjoyed high levels of mobility – and change – among those most affected by recent social changes, namely low-mobility women.


2020 ◽  
Vol 73 (1) ◽  
pp. 103-111
Author(s):  
D. Kalibekuly ◽  
◽  
Y.S. Chukubayev ◽  

The paper examines the dynamics of regional security in Norway as a part of Northern Europe. Being a political and geographical part of the Euro-Atlantic security system. Northern Europe, in its turn, is experiencing the impact of the confrontation between Russia and NATO. Norway's security policy analyzed from the perspective of a regional leader, as a NATO member country participating in the operations of the North Atlantic Alliance and as NATO's northern wing.


2018 ◽  
Vol 924 ◽  
pp. 482-485
Author(s):  
Min Seok Kang ◽  
Kevin Lawless ◽  
Bong Mook Lee ◽  
Veena Misra

We investigated the impact of an initial lanthanum oxide (La2O3) thickness and forming gas annealing (FGA) conditions on the MOSFET performance. The FGA has been shown to dramatically improve the threshold voltage (VT) stability of 4H-SiC MOSFETs. The FGA process leads to low VTshift and high field effect mobility due to reduction of the interface states density as well as traps by passivating the dangling bonds and active traps in the Lanthanum Silicate dielectrics. By optimizing the La2O3interfacial layer thickness and FGA condition, SiC MOSFETs with high threshold voltage and high mobility while maintaining minimal VTshift are realized.


2018 ◽  
Vol 14 (8) ◽  
pp. 1253-1273 ◽  
Author(s):  
Kees Nooren ◽  
Wim Z. Hoek ◽  
Brian J. Dermody ◽  
Didier Galop ◽  
Sarah Metcalfe ◽  
...  

Abstract. The impact of climate change on the development and disintegration of Maya civilisation has long been debated. The lack of agreement among existing palaeoclimatic records from the region has prevented a detailed understanding of regional-scale climatic variability, its climatic forcing mechanisms and its impact on the ancient Maya. We present two new palaeo-precipitation records for the central Maya lowlands, spanning the Pre-Classic period (1800 BCE–250 CE), a key epoch in the development of Maya civilisation. A beach ridge elevation record from world's largest late Holocene beach ridge plain provides a regional picture, while Lake Tuspan's diatom record is indicative of precipitation changes at a local scale. We identify centennial-scale variability in palaeo-precipitation that significantly correlates with the North Atlantic δ14C atmospheric record, with a comparable periodicity of approximately 500 years, indicating an important role of North Atlantic atmospheric–oceanic forcing on precipitation in the central Maya lowlands. Our results show that the Early Pre-Classic period was characterised by relatively dry conditions, shifting to wetter conditions during the Middle Pre-Classic period, around the well-known 850 BCE (2.8 ka) event. We propose that this wet period may have been unfavourable for agricultural intensification in the central Maya lowlands, explaining the relatively delayed development of Maya civilisation in this area. A return to relatively drier conditions during the Late Pre-Classic period coincides with rapid agricultural intensification in the region and the establishment of major cities.


Author(s):  
Arthur C. Trembanis ◽  
Enrico Duo ◽  
Stephanie Dohner ◽  
Edoardo Grottoli ◽  
Paolo Ciavola

Abstract. Developing and implementing a quick response post-storm survey protocol has the potential to improve impact assessments of coastal storms. Pre- and post-event surveys are essential to properly quantify the storm impacts on the coast. In this study, a combination of traditional RTK GPS and Unmanned Aerial Vehicle drone platform was utilized as part of a coordinated storm response workflow. The comprehensive approach employed in this pilot case study was conducted on the Emilia-Romagna coast (Italy), in the immediate aftermath of an extreme storm event that impacted the shoreline on the 5th–6th February 2015 called the Saint Agatha Storm. The activities were supported by timing information on the approaching storm provided by the regional early warning system. We collected aerial photos from a commercial off-the-shelf drone immediately after the Saint Agatha Storm and generated both orthomosaic and digital elevation models utilizing structure-from-motion photogrammetry techniques. The drone- based survey approach allowed us to quickly survey an area of 0.25 km2 within a 10-minute flight resulting in a ground sampling distance of 2.5 cm/pixel. Flooding and erosion impacts are analyzed and presented for the target study area. Limitations and possible applications for coastal management of the quick response post-storm surveying protocol are highlighted.


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