Distribution Map of Multi-Walled Carbon Nanotubes in a Refrigerant/Oil Mixture Within a 2.5 Ton Unitary Air-Conditioner

In recent years, nanoparticles have received considerable attention as a potential additive to heat transfer fluids (i.e. refrigerant) in order to increase the heat transfer capabilities of these fluids. The potential of carbon nanotubes (CNTs) to exit the compressor, migrate throughout a vapor compression air conditioning system, and possibly foul the components of such a system was experimentally investigated in this research. Six grams of CNTs were dispersed in the polyol ester oil used by a 2.5 ton (8.79 kW) unitary air conditioning system, which was continuously operated for 168 hours. After this time, the unit was shut down and dismantled in order to determine if and where the CNTs had migrated, and to discover any possible fouling. Of the six grams (92.6 grains) initially placed into the compressor, only approximately 2.5 grams (38.6 grains) were recovered from inside the compressor, leaving approximately 3.5 grams (54 grains) distributed throughout the system. A portion of the CNTs found in the system were in the process of flowing with the refrigerant, but the majority had become strongly adhered to the interior walls. The location of the heaviest fouling was found in the first 2-3 feet (0.61-0.91m) of each aluminum condenser circuit. The results indicate that the most conducive environment for CNTs to foul the interior tube walls is when the refrigerant is a superheated vapor. When the refrigerant was at or very close to 0% vapor quality, almost no fouling was observed. This work showed conclusively that CNTs will exit a scroll compressor and have high fouling potential when utilized in a standard vapor compression air conditioning system

Marie Olivieri Russell and Sarah Sundborg Long

Marie Olivieri Russell Dr. Russell attended Jefferson Medical College where she graduated top of her class in 1970. In addition to being the first woman to receive the Alumni Prize for highest cumulative GPA, in 1971 she became the first student to serve as a full voting member of the Board of Trustees at Jefferson. After graduation she completed both a residency in Pediatrics and a fellowship in Pediatric Hematology Oncology at Children’s Hospital of Philadelphia before continuing on as a part of their academic staff until 1981 and managing the Comprehensive Sickle Cell Program. After leaving Children’s and academic medicine Dr. Russell transitioned into Primary Care, eventually co-founding a pediatric practice for Crozer-Keystone Health System in Media, Pennsylvania. The practice later moved to Springfield, Pennsylvania, grew to include six physicians, and became part of Children’s Hospital of Philadelphia’s Primary Care Network. Over the years she also held faculty appointments at University of Pennsylvania, Hahnemann Medical College, and Drexel University. Dr. Russell retired in 2005 to spend more time with her family. Sarah Sundborg Long Dr. Long graduated from St. Francis College with a Bachelor’s of Science in Biology before entering Jefferson Medical College. Upon her graduation in 1970 she completed an Infectious Disease residency and fellowship at St. Christopher’s Hospital for Children in Philadelphia. She is currently the Chief for the Section of Infectious Diseases at St Christopher’s and a Professor of Pediatrics at Drexel University College of Medicine. Throughout her teaching career she has held more than seventy-five visiting professorships and earned a number of honors and awards, including most recently the Lindback Award. Dr. Long is the founding editor of Principles and Practice of Pediatric Infectious Disease as well as an associate editor of The Journal of Pediatrics and the Red Book Report of the Committee on Infectious Diseases of the American Academy of Pediatrics. Her main research areas are common infectious diseases and vaccine-preventable diseases in children.https://jdc.jefferson.edu/oral_histories/1010/thumbnail.jp

'Autism is the Arena and OCD is the Lion': Autistic adults' experiences of co-occurring obsessive-compulsive disorder and repetitive restricted behaviours and interests

Obsessive-compulsive disorder commonly co-occurs with autism. Research characterising the interplay between restricted, repetitive behaviours, activities and interests related to autism and obsessive-compulsive disorder symptoms has used theory-driven, bottom-up methodology. This study aimed to interview autistic adults about the subjective experience of differentiating between these phenomena. Semi-structured interviews were conducted with 15 autistic adults experiencing obsessive-compulsive disorder symptoms and repetitive behaviours, activities and interest. Transcripts were analysed using reflexive thematic analysis from a critical-realist, inductive orientation. Three overarching themes are presented. Participants viewed repetitive behaviours, activities and interest as intrinsic to their identity, while obsessive-compulsive disorder remained ego-dystonic and a perpetuator of anxiety. Conversely, repetitive behaviours, activities and interest was present across various emotions, often serving as a method to manage anxiety. Routinised behaviours and focused interests were considered by participants to be vulnerable to obsessive-compulsive disorder exploitation. Although participants reported masking both phenomena, the methods and motivations to mask differed. This research demonstrates the importance of delineating these experiences, with suggestions offered in how to explore this with autistic clients. Future research could explore narratives of masking obsessive-compulsive disorder across autistic and non-autistic people and investigate simultaneous co-occurrence of obsessive-compulsive disorder and repetitive behaviours, activities and interest; including how focused interests may influence obsessive-compulsive disorder and how repetitive routines may be intensified by obsessive-compulsive disorder. Lay Abstract: Repetitive behaviours and interests are a hallmark feature of autism. It is very common for autistic people to experience mental health difficulties, such as obsessive-compulsive disorder. Previous research has investigated similarities and differences between obsessive-compulsive disorder symptoms and repetitive behaviours in autism through questionnaires and observation studies. This is the first study to interview autistic adults about their personal experiences of differentiating between obsessive-compulsive disorder symptoms and repetitive behaviours related to autism. We interviewed 15 autistic adults who experience obsessive-compulsive disorder symptoms. We recorded these interviews and carefully analysed these to find themes. We found some differences between repetitive behaviours and obsessive-compulsive disorder. Participants said repetitive behaviours are part of who they are and what they want to be doing, whereas obsessive-compulsive disorder symptoms conflicted with how they view themselves. Obsessive-compulsive disorder was said to cause negative emotions, while participants said they experience lots of different emotions when doing repetitive behaviours. A similarity participants reported was trying to stop themselves from doing obsessive-compulsive disorder symptoms and repetitive behaviours that other people can see. There was also overlap between obsessive-compulsive disorder and repetitive behaviours. Participants talked about experiences when obsessive-compulsive disorder would take over routines and make them feel more intense and negative. Also, participants’ special interests were sometimes connected to the obsessions they experienced. We conclude that clinicians can use these findings to support conversations with autistic clients in differentiating between repetitive behaviours and obsessive-compulsive disorder symptoms. We also think that further research investigating how obsessive-compulsive disorder symptoms might be hidden by autistic and typically developing people is needed

Engineering Pathways of Nontraditional Students—an Update on NSF Award 1361058

Engineering Pathways of Nontraditional Students—an Update on NSF Award 1361058 A large‐scale longitudinal study of nontraditional engineering students has provided descriptive information about the access, pathways, and success of nontraditional engineering students. Nontraditional students hold the potential to increase not only the number of engineering students, but also the diversity of the engineering student body. This descriptive study laid the groundwork for a larger study of nontraditional student pathways. The study of nontraditional student pathways will reveal patterns in how nontraditional students choose majors, how they migrate, and where they succeed. This study uses the Multiple‐Institution Database for Investigating Engineering Longitudinal Development (MIDFIELD). MIDFIELD is a longitudinal, multi‐institutional, and multivariate dataset of over 209,737 engineering students. MIDFIELD is large enough to provide a better understanding of nontraditional students in public 4 year universities, identify conditions where they are more numerous and more successful, and explore the conditions that support their success. Whereas prior research has ignored or masked the contribution of nontraditional students to graduation statistics, this research focuses on nontraditional status and its associated outcomes. By studying what happens to those nontraditional students in particular, this project will draw attention to the educational outcomes of a population that currently comprises 10% of student enrollment, but represents some of the fastest growing pathways in US higher education

Sensitivity of Magnetospheric Multi-Scale (MMS) Mission Navigation Accuracy to Major Error Sources

The Magnetospheric Multiscale (MMS) mission consists of four satellites flying in formation in highly elliptical orbits about the Earth, with a primary objective of studying magnetic reconnection. The baseline navigation concept is independent estimation of each spacecraft state using GPS pseudorange measurements referenced to an Ultra Stable Oscillator (USO) with accelerometer measurements included during maneuvers. MMS state estimation is performed onboard each spacecraft using the Goddard Enhanced Onboard Navigation System (GEONS), which is embedded in the Navigator GPS receiver. This paper describes the sensitivity of MMS navigation performance to two major error sources: USO clock errors and thrust acceleration knowledge errors

Magnetospheric Multiscale Mission (MMS) Phase 2B Navigation Performance

The Magnetospheric Multiscale (MMS) formation flying mission, which consists of four spacecraft flying in a tetrahedral formation, has challenging navigation requirements associated with determining and maintaining the relative separations required to meet the science requirements. The baseline navigation concept for MMS is for each spacecraft to independently estimate its position, velocity and clock states using GPS pseudorange data provided by the Goddard Space Flight Center-developed Navigator receiver and maneuver acceleration measurements provided by the spacecraft's attitude control subsystem. State estimation is performed onboard in real-time using the Goddard Enhanced Onboard Navigation System flight software, which is embedded in the Navigator receiver. The current concept of operations for formation maintenance consists of a sequence of two maintenance maneuvers that is performed every 2 weeks. Phase 2b of the MMS mission, in which the spacecraft are in 1.2 x 25 Earth radii orbits with nominal separations at apogee ranging from 30 km to 400 km, has the most challenging navigation requirements because, during this phase, GPS signal acquisition is restricted to less than one day of the 2.8-day orbit. This paper summarizes the results from high-fidelity simulations to determine if the MMS navigation requirements can be met between and immediately following the maintenance maneuver sequence in Phase 2b

Navigation Operations for the Magnetospheric Multiscale Mission

The Magnetospheric Multiscale (MMS) mission employs four identical spinning spacecraft flying in highly elliptical Earth orbits. These spacecraft will fly in a series of tetrahedral formations with separations of less than 10 km. MMS navigation operations use onboard navigation to satisfy the mission definitive orbit and time determination requirements and in addition to minimize operations cost and complexity. The onboard navigation subsystem consists of the Navigator GPS receiver with Goddard Enhanced Onboard Navigation System (GEONS) software, and an Ultra-Stable Oscillator. The four MMS spacecraft are operated from a single Mission Operations Center, which includes a Flight Dynamics Operations Area (FDOA) that supports MMS navigation operations, as well as maneuver planning, conjunction assessment and attitude ground operations. The System Manager component of the FDOA automates routine operations processes. The GEONS Ground Support System component of the FDOA provides the tools needed to support MMS navigation operations. This paper provides an overview of the MMS mission and associated navigation requirements and constraints and discusses MMS navigation operations and the associated MMS ground system components built to support navigation-related operations