USMA Digital Commons (United States Military Academy, West Point)
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Magnesium-ion batteries for electric vehicles: Current trends and future perspectives
No full textLithium-ion batteries have enabled electric vehicles to achieve a foothold in the automobile market. Due to an increasing environmental consciousness, electric vehicles are expected to take a larger portion of the market, with the ultimate goal of supplanting traditional vehicles. However, the involved costs, sustainability, and technical limitations of lithium-ion batteries do create substantial obstacles to this goal. Therefore, this article aims at presenting magnesium-ion batteries as a potential replacement for lithium-ion batteries. Though still under development, magnesium-ion batteries show promise in achieving similar volumetric and specific capacities to lithium-ion batteries. Additionally, magnesium is substantially more abundant than lithium, allowing for the batteries to be cheaper and more sustainable. Numerous technical challenges related to cathode and electrolyte selection are yet to be solved for magnesium-ion batteries. This paper discusses the current state-of-the-art of magnesium-ion batteries with a particular emphasis on the material selection. Although, current research indicates that sulfur-based cathodes coupled with a (HMDS)2Mg-based electrolyte shows substantial promise, other options could allow for a better performing battery. This paper addresses the challenges (materials and costs) and benefits associated with developing these batteries. When overcoming these challenges, magnesium-ion batteries are posed to be a groundbreaking technology potentially revolutionizing the vehicle industry
Prestressed MF-FRP: Experimental Study of Rapid Retrofit Solution for Deteriorated Prestressed C-Channel Beams
No full textThis paper presents design and installation details and full-scale test results for a prestressed mechanically fastened fiber-reinforced polymer (MF-FRP) retrofit solution that restores the original operating and inventory rating of prestressed concrete C-channel bridge superstructures with prestress losses due to concrete deterioration and steel corrosion. A retrofit solution that can be installed rapidly and immediately restores prestress losses is desired to minimize impacts on commerce, public transportation, and emergency services. Six 9.41-m (30-ft) long C-channel beams were tested for three-point bending to failure. The results of the experimental study indicate that the MF-FRP retrofit is capable of immediately restoring deteriorated C-channel beams with a 36% reduction in capacity from the original operating and inventory ratings. In this study, the reduction in the capacity of the C-channel beams was induced in the lab by cutting the bottom strand of each stem of the C-channel beam to simulate total prestress losses at the point of maximum internal moment. Further, the results of the experimental study indicate that the examined MF-FRP retrofit solution can be installed in 4.1 labor hours per retrofitted C-channel beam. Therefore, a four-worker DOT maintenance crew can install the retrofit on up to seven beams in a single eight-hour workday. A layered sectional analysis can be used to predict the flexural capacity of retrofitted C-channel beams with very good accuracy
Solorigate attack — the challenge to cyber deterrence
Get PDFThe exploitation of SolarWinds’ network tool at a grand scale, based on publicly disseminated information from Congress and media, represents not only a threat to national security — but also puts the concept of cyber deterrence in question. My concern: Is there a disconnect between the operational environment and the academic research that we generally assume supports the national security enterprise?
Apparently, whomever launched the Solorigate attack was undeterred, based on the publicly disclosed size and scope of the breach. If cyber deterrence is not to be a functional component to change potential adversaries’ behavior, why is cyber deterrence given so much attention?
Maybe it is because we want it to exist. We want there to be a silver bullet out there that will prevent future cyberattacks, and if we want it to exist, then any support for the existence of cyber deterrence feeds our confirmation bias.
Herman Kahn and Irwin Mann’s RAND memo Ten Common Pitfalls from 1957 points out the intellectual traps when trying to make military analysis in an uncertain world. That we listen to what is supporting our general belief is natural — it is in the human psyche to do so, but it can mislead.
Here is my main argument — there is a misalignment between civilian academic research and the cyber operational environment. There are at least a few hundred academic papers published on cyber deterrence, from different intellectual angles and a variety of venues, seeking to investigate, explain and create an intellectual model how cyber deterrence is achieved.
Many of these papers transpose traditional models from political science, security studies, behavioral science, criminology and other disciplines, and arrange these established models to fit a cyber narrative. The models were never designed for cyber; the models are designed to address other deviate behavior. I do not rule out their relevance in some form, but I also do not assume that they are relevant.
The root causes of this misalignment I would like to categorize in three different, hopefully plausible explanations. First, few of our university researchers have military experience, and with an increasingly narrower group that volunteer to the serve, the problem escalates. This divide between civilian academia and the military is a national vulnerability
Classroom Aerosol Dispersion: Desk Spacing and Divider Impacts
No full textA study of aerosol dispersion was conducted in a university classroom using a CO2 tracer gas emitted from three source locations in a steady release, one source location per test. The tracer gas emitted from the single source location represented the potentially infectious aerosol droplets emitted from a single student, and was thus a way to examine the influence of one sick student on the rest of the class. Two parameters were adjusted during the testing – the spacing of the desks, which included a spread and compressed configuration, and the inclusion of three-sided clear dividers attached to the student desk surfaces. Tracer dispersion was measured through the use of monitors in 13 locations within the classroom, with 8 monitors representing seated student locations, four monitors representing a standing instructor along the classroom front, and one monitor at the return vent in the ceiling. As expected, spacing strongly influenced concentration levels at desks adjacent to the source location. The use of dividers reduced overall student and instructor location tracer concentrations when compared to desks without dividers in most cases. Finally, the influence of air change differences on the results were noted with consistent trends. The experimental construct provides a systematic means for classroom testing that may be broadly applicable to various configurations of classrooms beyond the one tested
Challenges and Opportunities for Generative Methods in the Cyber Domain
No full textLarge, high quality data sets are essential for training machine learning models to perform their tasks accurately. The lack of such training data has constrained machine learning research in the cyber domain. This work explores how Markov Chain Monte Carlo (MCMC) methods can be used for realistic synthetic data generation and compares it to several existing generative machine learning techniques. The performance of MCMC is compared to generative adversarial network (GAN) and variational autoencoder (VAE) methods to estimate the joint probability distribution of network intrusion detection system data. A statistical analysis of the synthetically generated cyber data determines the goodness of fit, aiming to improve cyber threat detection. The experimental results suggest that the data generated from MCMC fits the true distribution approximately as well as the data generated from GAN and VAE; however, the MCMC requires a significantly longer training period and is unproven for higher dimensional cyber data
Estimating the prevalence of heterochromia iridum from high-resolution digital yearbook portraits
No full textHeterochromia iridum (HI), or complete heterochromia, is a condition where an individual\u27s irises are of two different colors. It may be congenital, with or without a syndromic relationship, or acquired through injury, medication, or other means. Immaterial of its origin, HI is generally thought to be harmless and easily diagnosable. For these reasons, HI receives little attention in the medical literature, especially when it is not associated with a more concerning medical condition or cause. For example, a PubMed search on June 19, 2021 returned just 16 results for HI and complete heterochromia among its 32 million citations, and all 16 articles headlined HI\u27s relationship with a syndrome, abnormality, or disease. Not surprisingly, a precise measure of HI\u27s prevalence remains an open question, although it is considered rare. While it is possible HI is benign and presents no real medical risk, its association with troubling underlying medical conditions “warrants investigation . Moreover, it is difficult (if not impossible) to study potential correlations between HI and other more serious diseases without a better understanding of its prevalence. To the best of our knowledge, the most expansive attempt at estimating HI\u27s prevalence was undertaken by Stelzer, who personally examined over 25,000 Viennese people between 1 and 80 years old in the late 1960s. Notably, he only considered cases without a presumed pathological cause, and he reported an observed prevalence of 0.06313%
Reference Values for the Headache Impact Test-6 Questionnaire.
No full textOBJECTIVE: To determine reference values for the Headache Impact Test-6 (HIT-6) in a young, physically active cohort and to examine the influence of sex, concussion history, headache history, and competitive sport level on HIT-6 scores.
DESIGN: Cross-sectional.
SETTING: United States Service Academy.
PARTICIPANTS: United States Service Academy cadets (N=2678) completed an HIT-6 questionnaire as part of their annual concussion baseline assessment. Cadets with a recent concussion were excluded from baseline testing.
INTERVENTIONS: Not applicable.
MAIN OUTCOME MEASURES: Reference values were calculated and stratified by sex, concussion history, headache history, and competitive sport level. Mann-Whitney U and Kruskal-Wallis tests were used to examine the effect of sex, concussion history, headache history, and competitive sport level on HIT-6 scores (P\u3c.05).
RESULTS: Of the 3599 cadets baselined, 2687 cadets (23% female) agreed to participate in the study and completed the HIT-6. Female participants reported significantly worse HIT-6 scores compared with male participants both with (P
CONCLUSIONS: This is the first study to stratify HIT-6 data by sex, concussion history, headache history, and sport level in a collegiate population at risk for concussions. Sex and headache history appear to influence HIT-6 scores and should be given special consideration when interpreting health-related quality of life deficits due to headache
Performance tradeoffs for spare parts supply chains with additive manufacturing capability servicing intermittent demand
No full textPurpose
The study aims to investigate the impact of additive manufacturing (AM) on the performance of a spare parts supply chain with a particular focus on underlying spare part demand patterns. Design/methodology/approach
This work evaluates various AM-enabled supply chain configurations through Monte Carlo simulation. Historical demand simulation and intermittent demand forecasting are used in conjunction with a mixed integer linear program to determine optimal network nodal inventory policies. By varying demand characteristics and AM capacity this work assesses how to best employ AM capability within the network. Findings
This research assesses the preferred AM-enabled supply chain configuration for varying levels of intermittent demand patterns and AM production capacity. The research shows that variation in demand patterns alone directly affects the preferred network configuration. The relationship between the demand volume and relative AM production capacity affects the regions of superior network configuration performance. Research limitations/implications
This research makes several simplifying assumptions regarding AM technical capabilities. AM production time is assumed to be deterministic and does not consider build failure probability, build chamber capacity, part size, part complexity and post-processing requirements. Originality/value
This research is the first study to link realistic spare part demand characterization to AM supply chain design using quantitative modeling
Prioritize NATO integration for multidomain operations
Get PDFAfter U.S. forces implement the multidomain operations (MDO) concept, they will have entered a new level of complexity, with multidomain rapid execution and increased technical abilities and capacities. The U.S. modernization efforts enhance the country’s forces, but they also increase the technological disparity and challenges for NATO.
A future fight in Europe is likely to be a rapidly unfolding event, which could occur as an fait accompli attack on the NATO Eastern front. A rapid advancement from the adversary to gain as much terrain and bargaining power before the arrival of major U.S. formations from the continental U.S.
According to the U.S. Army Training and Doctrine Command (TRADOC) Pamphlet 525-3-1, “The U.S. Army in Multi-Domain Operations 2028,” a “fait accompli attack is intended to achieve military and political objectives rapidly and then to quickly consolidate those gains so that any attempt to reverse the action by the [United States] would entail unacceptable cost and risk.”
In a fait accompli scenario, limited U.S. Forces are in theater, and the initial fight rely on the abilities of the East European NATO forces. The mix is a high-low composition of highly capable but small, rapid response units from major NATO countries and regional friendly forces with less ability.
The wartime mobilization units and reserves of the East European NATO forces follow a 1990s standard, to a high degree, with partial upgrades in communications and technical systems. They represent a technical generation behind today’s U.S. forces. Even if these dedicated NATO allies are launching modernization initiatives and replace old legacy hardware (T72, BTR, BMP, post-Cold War-donated NATO surplus) with modern equipment, it is a replacement cycle that will require up to two decades before it is completed. Smaller East European NATO nations tend to have faster executed modernization programs, due to the limited number of units, but they still face the issue of integrating a variety of inherited hardware, donated Cold War surplus, and recently purchased equipment
The Shape of Things to Come: Why the Pentagon Must Embrace Soft Power to Compete with China
No full textAs the COIVD-19 pandemic forced the United States to scale down its massive Defender exercise in Europe, the Chinese military continued its multinational exercise programs with Cambodia, Russia, and Pakistan, despite China’s strict domestic lockdowns. These exercises highlight how China is wielding a form of military power commonly overlooked in assessments of its rise. Today, states leverage their armed forces not only for warfighting or coercion, but also to manage international relationships. Military power includes not only the capacity to conquer and compel, but also the ability to create advantage through attraction and persuasion—a concept I call “shaping.” Unlike military strategies of warfighting or coercion, shaping relies less on force and more on the use of persuasion to change the characteristics of other militaries, build closer ties with other states, and influence the behavior of allies. China’s leaders increasingly understand the value of using their military to shape the international system in their favor. American policymakers, if they wish to compete effectively, ought to take shaping more seriously as well