Adaptive Airborne Separation to Enable UAM Autonomy in Mixed Airspace

The excitement and promise generated by Urban Air Mobility (UAM) concepts have inspired both new entrants and large aerospace companies throughout the world to invest hundreds of millions in research and development of air vehicles, both piloted and unpiloted, to fulfill these dreams. The management and separation of all these new aircraft have received much less attention, however, and even though NASAs lead is advancing some promising concepts for Unmanned Aircraft Systems (UAS) Traffic Management (UTM), most operations today are limited to line of sight with the vehicle, airspace reservation and geofencing of individual flights. Various schemes have been proposed to control this new traffic, some modeled after conventional air traffic control and some proposing fully automatic management, either from a ground-based entity or carried out on board among the vehicles themselves. Previous work has examined vehicle-based traffic management in the very low altitude airspace within a metroplex called UTM airspace in which piloted traffic is rare. A management scheme was proposed in that work that takes advantage of the homogeneous nature of the traffic operating in UTM airspace. This paper expands that concept to include a traffic management plan usable at all altitudes desired for electric Vertical Takeoff and Landing urban and short-distance, inter-city transportation. The interactions with piloted aircraft operating under both visual and instrument flight rules are analyzed, and the role of Air Traffic Control services in the postulated mixed traffic environment is covered. Separation values that adapt to each type of traffic encounter are proposed, and the relationship between required airborne surveillance range and closure speed is given. Finally, realistic scenarios are presented illustrating how this concept can reliably handle the density and traffic mix that fully implemented and successful UAM operations would entail

An Environmental and Economic Analysis of the Printing Practices of Periodicals and Publications by the University of Rhode Island and Similar Universities Nationwide

An Environmental and Economic Analysis of the Printing Practices of Periodicals and Publications by the University of Rhode Island and Similar Universities Nationwide Matthew Cotton Faculty Sponsor: Thomas Husband, Natural Resources Science Being environmentally-friendly, or “Going Green”, is a relatively new way of thinking that provides both immediate and long term benefits for the environment and the planet while also creating new and exciting business and marketing opportunities. To tap into this movement requires a great deal of commitment, acceptance to change, and selflessness. It means altering one’s perception of the world and their place in it, along with the roles and responsibilities that all humans have to keep our planet as sustainable as possible, for as long as possible. Like many colleges and universities nationwide, the University of Rhode Island produces many publications and periodicals on an annual basis including the URI Catalog, Student Handbook, Undergraduate Admissions Viewbook and brochures, QuadAngles, and inAdvance@uri. Each of these institutions has their own views and policies on sustainability which translate into how they produce and distribute their individual publications. I have conducted an analysis of how selected colleges and universities do just that. Through numerous interviews as well as campus visits, I have become well-versed in the practices of other colleges and universities in regards to their publications and their stances on sustainability. The interviews were conducted with personnel in each institution’s publications office, asking the same set of questions during each interview. The campus visits consisted of me posing as a prospective undergraduate student attending an admissions information session and tour of the campus in order to discover how specific schools market their sustainability directly to prospective students. I have done the same with the University of Rhode Island: closely examining URI’s methods of producing and distributing printed materials, as well as their overall campus sustainability, in order to find out how URI compares with other institutions nationwide. My results will paint a picture of opportunity for the University of Rhode Island. As sustainability and the “Going Green” movement become increasingly important to society and in the minds of young, college-bound individuals, there are many ways for the University of Rhode Island to capitalize both environmentally and economically. I will demonstrate these opportunities in my project and show what URI has to do in order to cement itself as a leader in the sustainability movement

Alien Registration- Cotton, Louise B. (Millinocket, Penobscot County)

https://digitalmaine.com/alien_docs/7534/thumbnail.jp

On the feasibility of iron or chromium substitution for aluminium in the Al13-Keggin ion

Al-27 NMR measurements in the liquid and the solid state supplemented with chemical analysis of the mixed salts; unambiguously reveal that neither tetrahedral nor octahedral aluminium can be substituted by either iron or chromium in Al-13-Keggin ion salts prepared by conventional methods

On the Sum of Fisher-Snedecor F Variates and its Application to Maximal-Ratio Combining

Capitalizing on the recently proposed Fisher-Snedecor F composite fading model, in this letter, we investigate the sum of independent but not identically distributed (i.n.i.d.) Fisher-Snedecor F variates. First, a novel closed-form expression is derived for the moment generating function of the instantaneous signal-to-noise ratio. Based on this, the corresponding probability density function and cumulative distribution function of the sum of i.n.i.d. Fisher- Snedecor F variates are derived, which are subsequently employed in the analysis of multiple branch maximal-ratio combining (MRC). Specifically, we investigate the impact of multipath and shadowed fading on the outage probability and outage capacity of MRC based receivers. In addition, we derive exact closed-form expressions for the average bit error rate of coherent binary modulation schemes followed by an asymptotic analysis which provides further insights into the effect of the system parameters on the overall performance. Importantly, it is shown that the effect of multipath fading on the system performance is more pronounced than that of shadowing.Comment: 5 pages, 3 figure

For Spacious Skies: Self-Separation with "Autonomous Flight Rules" in US Domestic Airspace

Autonomous Flight Rules (AFR) are proposed as a new set of operating regulations in which aircraft navigate on tracks of their choice while self-separating from traffic and weather. AFR would exist alongside Instrument and Visual Flight Rules (IFR and VFR) as one of three available flight options for any appropriately trained and qualified operator with the necessary certified equipment. Historically, ground-based separation services evolved by necessity as aircraft began operating in the clouds and were unable to see each other. Today, technologies for global precision navigation, emerging airborne surveillance, and onboard computing enable traffic conflict management to be fully integrated with navigation procedures onboard the aircraft. By self-separating, aircraft can operate with more flexibility and fewer flight restrictions than are required when using ground-based separation. The AFR concept proposes a practical means in which self-separating aircraft could share the same airspace as IFR and VFR aircraft without disrupting the ongoing processes of Air Traffic Control. The paper discusses the context and motivation for implementing self-separation in US domestic airspace. It presents a historical perspective on separation, the proposed way forward in AFR, the rationale behind mixed operations, and the expected benefits of AFR for the airspace user community

Nutrition support therapy in acute kidney injury: Distinguishing dogma from good practice

Acute kidney injury (AKI) is a frequently observed complication in critically ill patients. Its presentation may range from the early risk of renal dysfunction to complete renal failure. Morbidity and mortality in the AKI patient increase with the decline of renal function. Appropriate nutrition therapy is essential in the medical management of the AKI patient. Assessment of nutritional requirements should take into account the patient’s underlying complication, comorbid medical conditions, and severity of the renal dysfunction. Various stages of AKI determine the direction of nutrition therapy. Additionally, understanding the macro- and micronutrient modifications and electrolyte and vitamin alterations that should be implemented are vital for better patient outcomes