Spot-on: Safe Fuel/Air Compression

The emission of fuel vapors into the atmosphere from underground storage tanks at filling stations is a common occurrence in many parts the world. The conditions of the vapor in the tanks vary significantly over a 24 hour period such that evaporation and excess air ingestion during the refueling process can cause tank over pressurization and subsequent emissions. At other times during a 24 hour cycle, pressures can fall below atmospheric pressure. The state of California has recognized this emissions problem and has enacted regulations to address it. Due to these low-emission environmental requirements in California, solutions must be implemented that do not entail release of these vapors into the atmosphere. One solution requires that the vapors fill a balloon during the appropriate times. However, the size of the balloon at typical inflation rates requires a significant amount of physical space (approximately 1000-2000 liters), which may not necessarily be available at filling stations in urban areas. Veeder-Root has a patent pending for a system to compress the vapors that are released to a 10:1 ratio, store this compressed vapor in a small storage tank, and then return the vapors to the original underground fuel tank when the conditions are thermodynamically appropriate (see Figure 1 for the schematic representation of this system). The limitation of the compressor, however, is that the compression phase must take place below the ignition temperature of the vapor. For a 10:1 compression ratio, however, the adiabatic temperature rise of a vapor would be above the ignition temperature. Mathematical modeling is necessary here to estimate the performance of the compressor, and to suggest paths in design for improvement. This report starts with a mathematical formulation of an ideal compressor, and uses the anticipated geometry of the compressor to state a simplified set of partial differential equations. The adiabatic case is then considered, assuming that the temporary storage tank is kept at a constant temperature. Next, the heat transfer from the compression chamber through the compressor walls is incorporated into the model. Finally, we consider the case near the valve wall, which is subject to the maximum temperature rise over the estimated 10,000 cycles that will be necessary for the process to occur. We find that for adiabatic conditions, there is a hot spot close to the wall where the vapor temperature can exceed the wall temperature. Lastly, we discuss the implications of our analysis, and its limitations

Plane wave irradiation of a layered system: resonance-based control over thermal runaway

[EN] The loss factor of a material is a key characteristic behind heat generation during EM heating. For typical ceramics, the loss factor increases exponentially with temperature potentially initiating thermal runaway which can damage the material through melting or cracking. Equilibrium of EM heating can be represented by a parametric plot of the average steady-state temperature as function of the applied power that is known as a power response curve. In a layered structure, for wavelengths of the incident wave that are much larger than the layer’s thickness, the power response curve is an S-shaped bifurcation diagram (or S-curve). Stable temperatures are low at the lower branch of the S-curve and may be very high (up to ~2000 K) at the upper branch. The recent analytical and numerical models show that, for a triple (lossless-lossy-lossless) layered system, when thickness of the structure is comparable with the wavelength, an electric field resonance can be achieved in the lossy layer. This resonance causes the S-curve to acquire another (middle) stable branch and become a double S-curve. That suggests that temperatures during thermal runaway may be controlled by the field resonance. However, these models assume two-side symmetric irradiation. In this paper, we show that the resonance producing a double S-curve can be achieved in a more practical scenario with one-side irradiation: in the system with a metal plate the resonance is achieve by choosing layer's thickness and triggering a constructive interference of the incident and reflected waves. A series of double S-curves computed with COMSOL Multiphysics are analyzed, and practical ways of controlling thermal runaway in EM heating of layered structures are discussed.The authors are grateful for the support from the US Air Force Office of Scientific Research, Award FA9550-18-1-0528.Mohekar, A.; Tilley, B.; Yakovlev, V. (2019). Plane wave irradiation of a layered system: resonance-based control over thermal runaway. En AMPERE 2019. 17th International Conference on Microwave and High Frequency Heating. Editorial Universitat Politècnica de València. 292-300. https://doi.org/10.4995/AMPERE2019.2019.9940OCS29230

Multifluid macroscopic approach to drying in papermaking

[EN] Drying process represents one of the main energy-consuming stages for a broad variety of manufacturers. However, despite its significant impact on energy efficiency, most implementations at manufacturing level do not operate within the optimal conditions. This work investigates the interplay among different parameters involved into the paper-drying process. To do so, we analyze both experimental and numerical results. The theoretical approach couples a non-isothermal flow, along with the heat transfer and transport of different fluids participating. Our results, experimental and numerical, show a good agreement according to the characteristic drying time scale. The results thus enable to estimate the impact of different mechanisms into drying process.This study was financially supported by the Center for Advanced Research in Drying (CARD), a US National Science Foundation Industry University Cooperative Research Center. CARD is located at Worcester Polytechnic Institute and the University of Illinois at Urbana-Champaign (co-site).Durán-Olivencia, F.; Farzad, M.; Tilley, B.; Yagoobi, J. (2018). Multifluid macroscopic approach to drying in papermaking. En IDS 2018. 21st International Drying Symposium Proceedings. Editorial Universitat Politècnica de València. 1285-1292. https://doi.org/10.4995/IDS2018.2018.7426OCS1285129

Enhanced Leak Detection

A key requirement for Veeder-Root’s Enhanced Leak Detection System is that it be able to test in situ for the presence of leaks at gasoline dispensing facilities. Aside from the obvious issues of safety and lost product, this functionality is obligatory for compliance with environmental standards mandated by federal and state oversight bodies, such as the California State Water Resources Control Board (SWRCB). The SWRCB demands a testing procedure that includes conditions as close to operational as possible, while still using environmentally safe gases as a test fluid. Although the test parameters (e.g., pressure) are allowed to deviate from operating conditions in order to facilitate the test procedure, a prescribed rescaling of the test thresholds must then be applied to account for the deviation. Whether the test is run at operation conditions or in a slightly different parameter regime, the fact that the testing must be done on the product and return lines after installation at a service station presents significant challenges in devising an effective test strategy

Communities, families and migration: some evidence from Cornwall

© Maney Publishing 2007Taking its cue from Pooley and Turnbull’s (1998) claim that there is no evidence of any difference in the propensity to migrate by region or settlement size, this article investigates the appropriate scale for migration research. It presents some preliminary findings from a micro-level study of three occupationally contrasting communities in Cornwall in the second half of the 19th century. Reconstructing the migration histories of a cohort of children from the 1851 census enumerators’ books and making use of local and online census and civil registration index databases, the study identifies some clear differences in migration patterns and propensity at the community level. Moving from patterns to processes it argues that labour markets and occupational structures remain the most important explanatory variables structuring migration, but that these were mediated at the individual level by the influence of the family which played a key role in facilitating or deterring movement

Clinical Sequencing Exploratory Research Consortium: Accelerating Evidence-Based Practice of Genomic Medicine

Despite rapid technical progress and demonstrable effectiveness for some types of diagnosis and therapy, much remains to be learned about clinical genome and exome sequencing (CGES) and its role within the practice of medicine. The Clinical Sequencing Exploratory Research (CSER) consortium includes 18 extramural research projects, one National Human Genome Research Institute (NHGRI) intramural project, and a coordinating center funded by the NHGRI and National Cancer Institute. The consortium is exploring analytic and clinical validity and utility, as well as the ethical, legal, and social implications of sequencing via multidisciplinary approaches; it has thus far recruited 5,577 participants across a spectrum of symptomatic and healthy children and adults by utilizing both germline and cancer sequencing. The CSER consortium is analyzing data and creating publically available procedures and tools related to participant preferences and consent, variant classification, disclosure and management of primary and secondary findings, health outcomes, and integration with electronic health records. Future research directions will refine measures of clinical utility of CGES in both germline and somatic testing, evaluate the use of CGES for screening in healthy individuals, explore the penetrance of pathogenic variants through extensive phenotyping, reduce discordances in public databases of genes and variants, examine social and ethnic disparities in the provision of genomics services, explore regulatory issues, and estimate the value and downstream costs of sequencing. The CSER consortium has established a shared community of research sites by using diverse approaches to pursue the evidence-based development of best practices in genomic medicine

Purinergic signalling and immune cells

This review article provides a historical perspective on the role of purinergic signalling in the regulation of various subsets of immune cells from early discoveries to current understanding. It is now recognised that adenosine 5'-triphosphate (ATP) and other nucleotides are released from cells following stress or injury. They can act on virtually all subsets of immune cells through a spectrum of P2X ligand-gated ion channels and G protein-coupled P2Y receptors. Furthermore, ATP is rapidly degraded into adenosine by ectonucleotidases such as CD39 and CD73, and adenosine exerts additional regulatory effects through its own receptors. The resulting effect ranges from stimulation to tolerance depending on the amount and time courses of nucleotides released, and the balance between ATP and adenosine. This review identifies the various receptors involved in the different subsets of immune cells and their effects on the function of these cells