351 research outputs found
Making Activated Carbon for Storing Gas
Solid disks of microporous activated carbon, produced by a method that enables optimization of pore structure, have been investigated as means of storing gas (especially hydrogen for use as a fuel) at relatively low pressure through adsorption on pore surfaces. For hydrogen and other gases of practical interest, a narrow distribution of pore sizes <2 nm is preferable. The present method is a variant of a previously patented method of cyclic chemisorption and desorption in which a piece of carbon is alternately (1) heated to the lower of two elevated temperatures in air or other oxidizing gas, causing the formation of stable carbon/oxygen surface complexes; then (2) heated to the higher of the two elevated temperatures in flowing helium or other inert gas, causing the desorption of the surface complexes in the form of carbon monoxide. In the present method, pore structure is optimized partly by heating to a temperature of 1,100 C during carbonization. Another aspect of the method exploits the finding that for each gas-storage pressure, gas-storage capacity can be maximized by burning off a specific proportion (typically between 10 and 20 weight percent) of the carbon during the cyclic chemisorption/desorption process
Pyrolysis processing for solid waste resource recovery
Solid waste resource recovery in space is effected by pyrolysis processing, to produce light gases as the main products (CH.sub.4, H.sub.2, CO.sub.2, CO, H.sub.2O, NH.sub.3) and a reactive carbon-rich char as the main byproduct. Significant amounts of liquid products are formed under less severe pyrolysis conditions, and are cracked almost completely to gases as the temperature is raised. A primary pyrolysis model for the composite mixture is based on an existing model for whole biomass materials, and an artificial neural network models the changes in gas composition with the severity of pyrolysis conditions
Pyrolysis process for producing fuel gas
Solid waste resource recovery in space is effected by pyrolysis processing, to produce light gases as the main products (CH.sub.4, H.sub.2, CO.sub.2, CO, H.sub.2O, NH.sub.3) and a reactive carbon-rich char as the main byproduct. Significant amounts of liquid products are formed under less severe pyrolysis conditions, and are cracked almost completely to gases as the temperature is raised. A primary pyrolysis model for the composite mixture is based on an existing model for whole biomass materials, and an artificial neural network models the changes in gas composition with the severity of pyrolysis conditions
Adsorption of Ammonia on Regenerable Carbon Sorbents
Results are presented on the development of reversible sorbents for the combined carbon dioxide, moisture, and trace-contaminant (TC) removal for use in Extravehicular Activities (EVAs), and more specifically in the Primary Life Support System (PLSS). The currently available life support systems use separate units for carbon dioxide, trace contaminants, and moisture control, and the long-term objective is to replace the above three modules with a single one. Data on sorption and desorption of ammonia, which is a major TC of concern, are presented in this paper. The current TC-control technology involves the use of a packed bed of acid-impregnated granular charcoal, which is non-regenerable, and the carbon-based sorbent under development in this project can be regenerated by exposure to vacuum at room temperature. In this study, several carbon sorbents were fabricated and tested for ammonia sorption. Ammonia-sorption capacity was related to carbon pore structure characteristics, and the temperature of oxidative carbon-surface treatment was optimized for enhanced ammonia-sorption performance
Adsorption of Carbon Dioxide, Ammonia, Formaldehyde, and Water Vapor on Regenerable Carbon Sorbents
Results are presented on the development of reversible sorbents for the combined carbon dioxide, moisture, and tracecontaminant (TC) removal for use in Extravehicular Activities (EVAs), and more specifically in the Primary Life Support System (PLSS). The currently available life support systems use separate units for carbon dioxide, trace contaminants, and moisture control, and the longterm objective is to replace the above three modules with a single one. Furthermore, the current TCcontrol technology involves the use of a packed bed of acidimpregnated granular charcoal, which is nonregenerable, and the carbonbased sorbent under development in this project can be regenerated by exposure to vacuum at room temperature. In this study, several carbon sorbents were fabricated and tested for simultaneous carbon dioxide, ammonia, formaldehyde, and water sorption. Multiple adsorption/vacuumregeneration cycles were demonstrated at room temperature, and also the enhancement of formaldehyde sorption by the presence of ammonia in the gas mixture
Torrefaction Processing for Human Solid Waste Management
This study involved a torrefaction (mild pyrolysis) processing approach that could be used to sterilize feces and produce a stable, odor-free solid product that can be stored or recycled, and also to simultaneously recover moisture. It was demonstrated that mild heating (200-250 C) in nitrogen or air was adequate for torrefaction of a fecal simulant and an analog of human solid waste (canine feces). The net result was a nearly undetectable odor (for the canine feces), complete recovery of moisture, some additional water production, a modest reduction of the dry solid mass, and the production of small amounts of gas and liquid. The liquid product is mainly water, with a small Total Organic Carbon content. The amount of solid vs gas plus liquid products can be controlled by adjusting the torrefaction conditions (final temperature, holding time), and the current work has shown that the benefits of torrefaction could be achieved in a low temperature range (< 250 C). These temperatures are compatible with the PTFE bag materials historically used by NASA for fecal waste containment and will reduce the energy consumption of the process. The solid product was a dry material that did not support bacterial growth and was hydrophobic relative to the starting material. In the case of canine feces, the solid product was a mechanically friable material that could be easily compacted to a significantly smaller volume (approx. 50%). The proposed Torrefaction Processing Unit (TPU) would be designed to be compatible with the Universal Waste Management System (UWMS), now under development by NASA. A stand-alone TPU could be used to treat the canister from the UWMS, along with other types of wet solid wastes, with either conventional or microwave heating. Over time, a more complete integration of the TPU and the UWMS could be achieved, but will require design changes in both units
Astrocyte pathology and the absence of non-cell autonomy in an induced pluripotent stem cell model of TDP-43 proteinopathy
Glial proliferation and activation are associated with disease progression in amyotrophic lateral sclerosis (ALS) and frontotemporal lobar dementia. In this study, we describe a unique platform to address the question of cell autonomy in transactive response DNA-binding protein (TDP-43) proteinopathies. We generated functional astroglia from human induced pluripotent stem cells carrying an ALS-causing TDP-43 mutation and show that mutant astrocytes exhibit increased levels of TDP-43, subcellular mislocalization of TDP-43, and decreased cell survival. We then performed coculture experiments to evaluate the effects of M337V astrocytes on the survival of wild-type and M337V TDP-43 motor neurons, showing that mutant TDP-43 astrocytes do not adversely affect survival of cocultured neurons. These observations reveal a significant and previously unrecognized glial cell-autonomous pathological phenotype associated with a pathogenic mutation in TDP-43 and show that TDP-43 proteinopathies do not display an astrocyte non-cell-autonomous component in cell culture, as previously described for SOD1 ALS. This study highlights the utility of induced pluripotent stem cell-based in vitro disease models to investigate mechanisms of disease in ALS and other TDP-43 proteinopathies
Pest categorisation of Phymatotrichopsis omnivora
The Panel on Plant Health performed a pest categorisation of Phymatotrichopsis omnivora, the causal
agent of Phymatotrichum root rot of more than 2,000 dicotyledonous plant species, for the EU. The
pest is listed as Trechispora brinkmannii in Annex IAI of Directive 2000/29/EC. P. omnivora is a welldefined fungal species and reliable methods exist for its detection and identification. It is present in
south-western USA, northern Mexico, Libya and Venezuela. The pest is not known to occur in the EU.
P. omnivora has an extremely wide host range; quantitative impacts have been documented for
Gossypium spp. (cotton), Medicago sativa (alfalfa), Malus domestica (apple), Prunus persica (peach)
and Vitis vinifera (grapevine) as the major cultivated hosts. All major hosts and pathways of entry of
the pest into the EU are currently regulated, except for soil and growing media attached or associated
with plants originating in Libya. Host availability and climate and edaphic matching suggest that
P. omnivora could establish in parts of the EU and further spread mainly by human-assisted means. The
pest infects the roots causing wilting and death of its host plants. The introduction of the pest in the EU
territory would potentially cause direct and indirect impacts at least to cotton, alfalfa, apple, peach and
grapevine production. The main uncertainties concern the host range, the extrapolation to the EU of
the climatic and edaphic conditions favouring the disease in some of the infested areas, the role of
conidia in the epidemiology of the disease and the magnitude of potential impacts to the EU. P.
omnivora meets all the criteria assessed by EFSA for consideration as potential Union quarantine pest.
The criteria for considering P. omnivora as a potential Union regulated non-quarantine pest are not met,
since the pest is not known to occur in the EU
Pest categorisation of Melampsora farlowii
Following a request from the European Commission, the EFSA Panel on Plant Health performed a pest
categorisation of Melampsora farlowii, a well-defined and distinguishable fungus of the family
Melampsoraceae. M. farlowii is the causal agent of a leaf and twig rust of hemlocks (Tsuga spp.) in
eastern North America. The pathogen is regulated in Council Directive 2000/29/EC (Annex IAI) as a
harmful organism whose introduction into the EU is banned. M. farlowii is not reported to be present in
Europe and could enter the EU via host plants for planting and cut branches. Cones and fruits are listed
as plant parts that can carry the pest in trade and transport, but are not regulated. The pathogen could
establish in the EU, as climatic conditions are favourable and Tsuga spp. have been planted as
ornamentals and in plantations in several EU countries. M. farlowii would be able to spread following
establishment by human movement of host plants for planting and cut branches, as well as natural
spread. Should the pathogen be introduced in the EU, impacts can be expected on Tsuga spp.
plantations, ornamental trees and especially nurseries. Hemlock rust is considered a destructive rust
attacking Tsuga spp., particularly Tsuga canadensis in nurseries. The main uncertainties concern whether
the impact of the pathogen in plantations under European conditions could be different than observed in
eastern North America, whether fruit/cones of Tsuga can be a pathway of entry, and the dissemination
potential of the pathogen under European conditions. However, M. farlowii is found in North America in
most of the natural distribution range of T. canadensis, suggesting little dispersal limitation of the
pathogen. The criteria assessed by the Panel for consideration as a potential quarantine pest are met,
whilst, for regulated non-quarantine pests, the criterion on the pest presence in the EU is not me
Pest categorisation of Cronartium harknessii, Cronartium kurilense and Cronartium sahoanum
Following a request from the European Commission, the EFSA Panel on Plant Health performed a pest
categorisation of Cronartium harknessii, Cronartium kurilense and Cronartium sahoanum, which are
well-defined and distinguishable tree fungal pathogens of the family Cronartiaceae. In 2018, these
species were moved from the genus Endocronartium to the genus Cronartium. These pathogens are
not known to be present in the EU and are regulated in Council Directive 2000/29/EC (Annex IAI) (as
non-European Endocronartium spp.) as harmful organisms whose introduction into the EU is banned.
These three fungi are autoecious rusts completing their life cycle on Pinus spp. C. harknessii is known
as the western gall rust or pine-pine gall rust in North America (Canada, the USA and Mexico).
C. kurilense and C. sahoanum are reported from Russia (North Kuril Islands) and Japan. The
pathogens could enter the EU via host plants for planting and cut branches. The pathogens could
establish in the EU, as climatic conditions are favourable and Pinus spp. are common. The pathogens
would be able to spread following establishment by movement of host plants for planting and cut
branches, as well as natural spread. Should these pathogens be introduced in the EU, impacts can be
expected on pine forests, plantations, ornamental trees and nurseries. The pathogens cause formation
of stem galls, which kill young trees and result in stem defect in older trees. The main knowledge gap
concerns the limited available information on C. kurilense and C. sahoanum compared to C. harknessii.
The criteria assessed by the Panel for consideration of C. harknessii, C. kurilense and C. sahoanum as
potential quarantine pests are met, whilst, for regulated non-quarantine pests, the criterion on the
pest presence in the EU is not met
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