Assessing the impact of FAME and diesel fuel composition on stability and vehicle filter blocking

In recent years, there has been an impetus in the automotive industry to develop newer diesel injection systems with a view to reducing fuel consumption and emissions. This development has led to hardware capable of higher pressures, typically up to 2500 bar. An increase in pressure will result in a corresponding increase in fuel temperature after compression with studies showing changes in fuel temperatures of up to 150 °C in 1000-2500 bar injection systems. Until recently, the addition of Fatty Acid Methyl Esters, FAME, to diesel had been blamed for a number of fuel system durability issues such as injector deposits and fuel filter blocking. Despite a growing acceptance within the automotive and petrochemical industries that FAME is not solely to blame for diesel instability, there is a lack of published literature in the area, with many studies still focusing on FAME oxidation to explain deposit formation and hardware durability.The majority of studies into diesel degradation are conducted under non-representative laboratory conditions, or are extrapolated from the deposits found in filters from vehicles with failed injectors. In this study, the cause of this degradation was investigated by using a novel High Pressure Common Rail (HPCR) non-firing rig designed to mimic a diesel common rail system, simulating realistic, albeit accelerated, operating conditions. The degree of deposition on the system fuel filter was monitored, for both petroleum diesel (B0), RF79 (B0), Bx (where x is percentage volume/volume of FAME) and surrogate diesel fuel components. A systematic study of synthetic surrogates demonstrated that, as well as FAME, any base fuel component, under sufficiently high pressures and temperatures experienced in the HPCR are prone to degradation irrespective of the concentration of the component in the original fuel. The most unstable component acts as the instigator, thus promoting fuel oxidation. The other components in the fuel such as FAME, aromatic and cycloalkane portions will also oxidise and eventually polymerise to form solids blocking the filter. This also demonstrates that while a large body of work on the oxidative instability of biodiesel in the chemical laboratory is indicative of instability this does not mimic what is seen under more realistic vehicle conditions and the focus on FAME instability is misleading.<br/

Assessing the impact of FAME and diesel fuel composition on stability and vehicle filter blocking

In recent years, there has been an impetus in the automotive industry to develop newer diesel injection systems with a view to reducing fuel consumption and emissions. This development has led to hardware capable of higher pressures, typically up to 2500 bar. An increase in pressure will result in a corresponding increase in fuel temperature after compression with studies showing changes in fuel temperatures of up to 150 °C in 1000-2500 bar injection systems. Until recently, the addition of Fatty Acid Methyl Esters, FAME, to diesel had been blamed for a number of fuel system durability issues such as injector deposits and fuel filter blocking. Despite a growing acceptance within the automotive and petrochemical industries that FAME is not solely to blame for diesel instability, there is a lack of published literature in the area, with many studies still focusing on FAME oxidation to explain deposit formation and hardware durability.The majority of studies into diesel degradation are conducted under non-representative laboratory conditions, or are extrapolated from the deposits found in filters from vehicles with failed injectors. In this study, the cause of this degradation was investigated by using a novel High Pressure Common Rail (HPCR) non-firing rig designed to mimic a diesel common rail system, simulating realistic, albeit accelerated, operating conditions. The degree of deposition on the system fuel filter was monitored, for both petroleum diesel (B0), RF79 (B0), Bx (where x is percentage volume/volume of FAME) and surrogate diesel fuel components. A systematic study of synthetic surrogates demonstrated that, as well as FAME, any base fuel component, under sufficiently high pressures and temperatures experienced in the HPCR are prone to degradation irrespective of the concentration of the component in the original fuel. The most unstable component acts as the instigator, thus promoting fuel oxidation. The other components in the fuel such as FAME, aromatic and cycloalkane portions will also oxidise and eventually polymerise to form solids blocking the filter. This also demonstrates that while a large body of work on the oxidative instability of biodiesel in the chemical laboratory is indicative of instability this does not mimic what is seen under more realistic vehicle conditions and the focus on FAME instability is misleading.<br/

Advanced manufacturing process design for Mesenchymal Stromal Cell therapies

For decades, the potential immunomodulatory effects of Mesenchymal Stromal Cells (MSCs) have prompted numerous cell-therapy clinical investigations targeting various diseases such as graft-versus-host disease and autoimmune diseases. Despite their ubiquitous usage in clinical trials, significant challenges related to their manufacturing and biological variabilities have led to poorly reproducible outcomes of therapeutic efficacy. Therefore, identification of validated critical quality attributes (CQAs) correlative to therapeutic function is of great interest to the MSC community. Such CQAs would also permit identification of critical process parameters (CPPs) to achieve and maintain MSC quality while producing a high yield. In this study, we designed and tested a “smart” feedback-controlled hollow fiber-based bioreactor for maintaining nutrient and waste levels for human umbilical cord tissue-derived MSC expansions. The bioreactor platform is a semi-autonomous system complete with in-line sensors, modeling, data-driven controllers, and an automated sampling platform. The small-scale system reduced costs, labor, time, and perturbations and improved yields of MSC products using a hollow fiber cartridge that closely models the basic design of the large-scale Quantum Cell Expansion System. Our feedback-controlled bioreactor responded to in-line glucose and lactate levels while recorded pH and dissolved oxygen measurements. This information was fed into a controller, which auto-calculates cell growth rates based on our developed mathematical model, and subsequently regulated media feed rates to support cell growth and nutrient requirements. Compared to the manual expansion process, the automated expansion processes showed higher yields and comparative therapeutic potency of MSCs, indicated by indolamine 2,3-dioxygenase assay and T cell proliferation assay. Future directions of our study propose to correlate metabolites and secreted proteins in culture media as putative CQAs that can be used as in-line predictors of MSC yield and therapeutic potency. Moreover, we aim to maintain a metabolic and secretory profile throughout MSC expansions enabled by real-time modulation of CPPs and scale up of the “smart” bioreactor. The proposed bioprocess for MSC products can be adapted and applied to industrial cell therapy manufacturing and can enable high-yield and high-quality products while minimizing variabilities. Please click Additional Files below to see the full abstract

Ultra-Stable Environment Control for the NEID Spectrometer: Design and Performance Demonstration

Two key areas of emphasis in contemporary experimental exoplanet science are the detailed characterization of transiting terrestrial planets, and the search for Earth analog planets to be targeted by future imaging missions. Both of these pursuits are dependent on an order-of-magnitude improvement in the measurement of stellar radial velocities (RV), setting a requirement on single-measurement instrumental uncertainty of order 10 cm/s. Achieving such extraordinary precision on a high-resolution spectrometer requires thermo-mechanically stabilizing the instrument to unprecedented levels. Here, we describe the Environment Control System (ECS) of the NEID Spectrometer, which will be commissioned on the 3.5 m WIYN Telescope at Kitt Peak National Observatory in 2019, and has a performance specification of on-sky RV precision < 50 cm/s. Because NEID's optical table and mounts are made from aluminum, which has a high coefficient of thermal expansion, sub-milliKelvin temperature control is especially critical. NEID inherits its ECS from that of the Habitable-zone Planet Finder (HPF), but with modifications for improved performance and operation near room temperature. Our full-system stability test shows the NEID system exceeds the already impressive performance of HPF, maintaining vacuum pressures below $10^{-6}$ Torr and an RMS temperature stability better than 0.4 mK over 30 days. Our ECS design is fully open-source; the design of our temperature-controlled vacuum chamber has already been made public, and here we release the electrical schematics for our custom Temperature Monitoring and Control (TMC) system.Comment: Accepted for publication in JATI

The James Webb Space Telescope Mission

Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least $4m$. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the $6.5m$ James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 years, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space Telescope Overview, 29 pages, 4 figure