Large-Scale Demonstration of Liquid Hydrogen Storage with Zero Boiloff for In-Space Applications

Cryocooler and passive insulation technology advances have substantially improved prospects for zero-boiloff cryogenic storage. Therefore, a cooperative effort by NASA s Ames Research Center, Glenn Research Center, and Marshall Space Flight Center (MSFC) was implemented to develop zero-boiloff concepts for in-space cryogenic storage. Described herein is one program element - a large-scale, zero-boiloff demonstration using the MSFC multipurpose hydrogen test bed (MHTB). A commercial cryocooler was interfaced with an existing MHTB spray bar mixer and insulation system in a manner that enabled a balance between incoming and extracted thermal energy

The Influence of Trickle Irrigation on the Quality of Irrigation Return Flow

The influence of trickle irrigation on the quality of irrigation return flow was investigated in a field study and by means of computer simulation models. Six undisturbed buried monolith lysimeters were utilized to quantify the leachate from treatment including two different qualities of irrigation water applied through a trickle irrigation system. Both moisture and salt balances were followed inside and outside the lysimeters during a growing season the remainder of the calendar year. A sorghum crop was grown on the lysimeters and in the adjacent area. Irrigation was scheduled based on pan evaporation losses. The irrigation water of high salt content was obtained from a deep well while the irrigation water of low salt content was drawn from the district irrigation canal. The water balance monitored by the neutron probe showed that differences between inside and outside lysimeters were small. The soil contained significant amounts of salt at the begining of the experiment and trends in the leachate concentration resulting from irrigation treatment are difficult to see after one year of monitoring. Differences between paired lysimeters are large indicating large variability in soil characteristics across the field. Differences in water use inside and outside the lysimeters indicated that during the 1974 growing season, which was dryer than normal, the sorghum crop may have extracted approximately 8% of the water required from the water table. Yield and growth data indicated that the plant root environment inside and outside lysimeters were relatively comparable. Nitrogen, saline water and irrigation treatments did not significantly influ- ence growth and yields of sorghum in 1974. During the test period, N03-N loss in effluents ranged from a low of 14 kg/ha from a lysimeter treated with 112kg/ha to a high of a- bout 75 kg/ha from a lysimeter treated with 224 kg/ha of N. Nitrate losses were negligible compared to checks when N application rates to sorghum were 112 kg/ha. Most of the N03-N losses occurred during non-cropped periods when lysimeter drainage volumes were at a maximum. Total salt in drainage waters ranged from about 2600 to 4200 kg/ha during the test period. Inherent soil variability was an important factor in salt and nitrate loss in drainage waters from the lysimeters

An Investigation of the Return Flow from Irrigated Land

Recent trends in agricultural have lead to the intensification of crop production in areas with long growing seasons and ample solar radiation. Unfortunately, these areas also often have limited water supplies, and the water available is often salty. When this water is used for irrigation, the salts are concentrated in soil solution. The application of fertilizer also increases the concentration of certain salts in soil. Thus, the water that leaches from an irrigated field will have greater concentrations of ion than the irrigation water applied. Little information exists, however, on the flux of ions or soil solution below the root zone of cropped fields. Such information is needed before we can learn how we might better manage our activities to minimize the pollution that may be associated with the leachate from agricultural fields. This project included both a field study and a modeling effort both directed at elucidating the influence of irrigation water quality on the quantity and quality of irrigation return flow by leaching below the root zone. The field work consisted of the installation of six large buried monolith lysimeters equipped with appropriate drainage devices. Suction water samples were collected for 8 months including the cropping season. The sorghum crop grown on paired lysimeters was irrigated with a high salt and low salt water and was fertilized with different levels of nitrogen. Although care was taken to secure lysimeters with similar soil, large differences between the volume of leachate and the concentration of ions in the leachate were found. During the period the measurements were made, the changes in concentration of leachate were not attributable to the treatments applied. The modeling effort was directed toward assembling and testing the following components of an overall water-salt-nutrients balance model: a.: Water and heat flow model to calculate the influence of moisture and temperature gradients on the movement of water between the source(s) and sinks within the system, b. An ion exchange equilibrium model to calculate the salt balance, c. A nitrogen model to calculate complex nitrogen transfers which take place within the soil, and d. A root oxygen supply model to calculate the sink strength for oxygen and ultimately the distribution of root water uptake within the soil profile. These components of the overall model have been programmed, tested, documented, and are presented in this report

Feasibility Study of the Effects of Water Quality on Soil Properties in the Red River Valley

The suitability of water for irrigation depends upon many factors, of primary concern is the quantity and quality of salts present in the water Ayers and Wescot1. If total dissolved solids in the irrigation water are too high, salts accumulate in the crop root zone to the extent that yields are reduced. Excessive soil salinity means the crops have difficulty extracting water from the soil solution. The other problems with respect to salinity are concerned with the effects of water quality on permeability of soil to water. The effects of specific ions such as Na or lack of salts in the water can reduce permeability to the extent that crops are not adequately supplied with water and yields are reduced. As pointed out by Rhoades and Ingvalson > and Frenkel, Goertzen and Rhoades2 one of the major factors affecting the suitability of water for irrigation is its sodicity hazard usually expressed as SAR. According to these investigators, our greatest limitation in assessing the sodium hazard is our inability to predict how the water will affect soil structure and permeability. This may be because soil structural stability or instability is a function of many factors. The effect of Na on soil structure can be modified by other soil properties such as texture, organic matter, etc. In Texas, Naghshineh-Pour, Kunze and Carson (6) stated that sodium absorption ratio (SAR), exchangeable Na percentage (ESP), electrolyte concentration, clay content, free iron oxides and clay mineral species are important factors involved in permeability of selected soils. Saffaf (9) noted the decrease of unsaturated hydraulic conductivity with decreasing electrolyte concentrations and increasing the SAR (sodium absorption ratio) of the soil solution was especially pronounced for swelling clay soils. Water in the Red River Basin is often high in salinity and in sodium concentrations (high SAR). Studies evaluated the influences of present and "predicted after reclamation" dissolved solids (TDS) and SAR on permeability of different soils in the Red River Basin. These studies should give some insight as to the effect of present levels of SAR on soil structure and permeability. It was also the purpose of this investigation to evaluate the effects of reduced SAR and total dissolved solids(TDS) on soil permeability. The permeability to rainfall (low TDS) of soils leached with different levels of SAR and salinity was simulated and determined in the laboratory. 1 Contributions of Texas AGM Research and Extension Center at Chillicothe-Vernon, Dallas, Munday and Texas A&M Water Resources Institute; College Station and supported in part by the Tulsa District, U.S. Corps of Engineers. 2 Professor, Chillicothe-Vernon; Associate Professor, Dallas; Director, Water Resources Institute, College Station; Research Engineer, Munday; and formerly Professor, Chillicothe-Vernon

A study on text-score disagreement in online reviews

In this paper, we focus on online reviews and employ artificial intelligence tools, taken from the cognitive computing field, to help understanding the relationships between the textual part of the review and the assigned numerical score. We move from the intuitions that 1) a set of textual reviews expressing different sentiments may feature the same score (and vice-versa); and 2) detecting and analyzing the mismatches between the review content and the actual score may benefit both service providers and consumers, by highlighting specific factors of satisfaction (and dissatisfaction) in texts. To prove the intuitions, we adopt sentiment analysis techniques and we concentrate on hotel reviews, to find polarity mismatches therein. In particular, we first train a text classifier with a set of annotated hotel reviews, taken from the Booking website. Then, we analyze a large dataset, with around 160k hotel reviews collected from Tripadvisor, with the aim of detecting a polarity mismatch, indicating if the textual content of the review is in line, or not, with the associated score. Using well established artificial intelligence techniques and analyzing in depth the reviews featuring a mismatch between the text polarity and the score, we find that -on a scale of five stars- those reviews ranked with middle scores include a mixture of positive and negative aspects. The approach proposed here, beside acting as a polarity detector, provides an effective selection of reviews -on an initial very large dataset- that may allow both consumers and providers to focus directly on the review subset featuring a text/score disagreement, which conveniently convey to the user a summary of positive and negative features of the review target.Comment: This is the accepted version of the paper. The final version will be published in the Journal of Cognitive Computation, available at Springer via http://dx.doi.org/10.1007/s12559-017-9496-

Learning Interpretable Rules for Multi-label Classification

Multi-label classification (MLC) is a supervised learning problem in which, contrary to standard multiclass classification, an instance can be associated with several class labels simultaneously. In this chapter, we advocate a rule-based approach to multi-label classification. Rule learning algorithms are often employed when one is not only interested in accurate predictions, but also requires an interpretable theory that can be understood, analyzed, and qualitatively evaluated by domain experts. Ideally, by revealing patterns and regularities contained in the data, a rule-based theory yields new insights in the application domain. Recently, several authors have started to investigate how rule-based models can be used for modeling multi-label data. Discussing this task in detail, we highlight some of the problems that make rule learning considerably more challenging for MLC than for conventional classification. While mainly focusing on our own previous work, we also provide a short overview of related work in this area.Comment: Preprint version. To appear in: Explainable and Interpretable Models in Computer Vision and Machine Learning. The Springer Series on Challenges in Machine Learning. Springer (2018). See http://www.ke.tu-darmstadt.de/bibtex/publications/show/3077 for further informatio

Clinical characteristics of rod and cone photoreceptor dystrophies in patients with mutations

METHODS. Eight patients-four diagnosed with retinitis pigmentosa (RP) and four with conerod dystrophy (CRD), carrying causal C8orf37 mutations-were clinically evaluated, including extensive medical history taking, slit-lamp biomicroscopy, ophthalmoscopy, kinetic perimetry, electroretinography (ERG), spectral-domain optical coherence tomography (SD-OCT), autofluorescence (AF) imaging, and fundus photography. RESULTS. In families A and D, respectively, one and three patients showed a classic RP phenotype with night blindness followed by concentric loss of visual field. Severe visual loss to light perception occurred early in the course of the disease. The symptoms initiated during infancy (family A) or adolescence (family D). Ophthalmoscopy revealed macular atrophy, bone spicules, attenuated vessels, and waxy pale optic discs. SD-OCT showed profound photoreceptor degeneration and AF demonstrated atrophy of the retinal pigment epithelium (RPE). ERG responses were nonrecordable in these patients. In families B and C, the patients were diagnosed with CRD. Initial symptoms were photophobia or loss of visual acuity and occurred during infancy (family B) or adolescence (family C). Ophthalmoscopy and AF revealed profound macular RPE atrophy and SD-OCT demonstrated macular photoreceptor degeneration. ERG responses were severely reduced in a cone-rod pattern or were nonrecordable. Interestingly, both patients in family B demonstrated polydactyly. CONCLUSIONS. Mutations in C8orf37 give rise to an early or adolescent-onset autosomal recessive CRD or RP phenotype with early macular atrophy. The occurrence of postaxial polydactyly in one family suggests a syndromic phenotype, which may indicate C8orf37 has a ciliary function

TRY plant trait database - enhanced coverage and open access

Plant traits-the morphological, anatomical, physiological, biochemical and phenological characteristics of plants-determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait-based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits-almost complete coverage for 'plant growth form'. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait-environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives

Welfare Reform, Precarity and the Re-Commodification of Labour

While welfare reform matters for workers and workplaces, it is peripheral in English-language sociology of work and industrial relations research. This article’s core proposition is that active labour market policies (ALMPs) are altering the institutional constitution of the labour market by intensifying market discipline within the workforce. This re-commodification effect is specified drawing on Marxism, comparative institutionalism, German-language sociology, and English-language social policy analysis. Because of administrative failures and employer discrimination, however, ALMPs may worsen precarity without achieving the stated goal of increasing labour-market participation

Low Frequency (100-600 MHz) Searches with Axion Cavity Haloscopes

We investigate reentrant and dielectric loaded cavities for the purpose of extending the range of axion cavity haloscopes to lower masses, below the range where the Axion Dark Matter eXperiment (ADMX) has already searched. Reentrant and dielectric loaded cavities were simulated numerically to calculate and optimize their form factors and quality factors. A prototype reentrant cavity was built and its measured properties were compared with the simulations. We estimate the sensitivity of axion dark matter searches using reentrant and dielectric loaded cavities inserted in the existing ADMX magnet at the University of Washington and a large magnet being installed at Fermilab.Comment: 33 pages, 24 figure