3,779 research outputs found
Chemistry and Apparent Quality of Surface Water and Ground Water Associated with Coal Basins
Personnel of the Arkansas Mining and Mineral Resources Research Institute conducted preliminary investigations on the chemistry and quality of surface and ground water associated with 12 coal-bearing sub-basins in the Arkansas Valley coal field. The coal field is approximately 60 miles long and 33 miles wide but only in 12 areas coal is thick enough and has proper quality to be termed commercial. Both surface and underground sample sites were established in each of the sub-basins with some minor variations in four areas where not all types of sites could be located. Water was collected from 19 surface points and 19 underground points in the established areas. Both field and laboratory analyses were made and elemental contents are reported herein. In the main, the chemistry and water quality suggests that all water is suitable for agricultural and industrial uses. To obtain potable water, treatment must be made to reduce calcium, magnesium, sodium sulfate and iron. The mineral content of the water is due to its contact with coal-bearing zones and, as such, reflects the mineral content of the coal. However, it is recommended that additional studies on the petrography and geochemistry of the coal, overburden and underburden is in order. Also, it is recommended that at least one detailed study be made of one of the coal sub-basins where geologic parameters can be completely established with regard to hydrogeology. This report is an important first step in determining the character and quality of Arkansas coal which must be fully understood to fully utilize this important mineral resource
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Correlated analytical studies of organic material from the Tagish Lake carbonaceous chondrite
We report on correlated studies of organic material using SIMS, FIB-SEM, and TEM
Chemical equilibrium of ablation materials including condensed species
Equilibrium is determined by finding chemical composition with minimum free energy. Method of steepest descent is applied to quadratic representation of free-energy surface. Solution is initiated by selecting arbitrary set of mole fractions, from which point on free-energy surface is computed
Science and user‐based co‐development of a farmland earthworm survey facilitated using digital media: insights and policy implications
Science–farming partnerships can improve our understanding of how land management behaviours sustain or enhance life-sustaining soil ecosystems. However, it remains a challenge to establish partnerships between researchers and practitioners that complement the ways in which farmers acquire and value knowledge and can also advance soil science. A pilot study was conducted to explore these issues in relation to earthworm monitoring. It showed that farmers were interested in comparing their field results to research experiments to inform their decision-making. Social media was used to support farmers' earthworm monitoring schemes, with a concomitant sampling of research experiments to create capacity for shared learning. Constructive feedback from the scientific community was sought using an online
questionnaire. An Autumn 2018 survey generated 152 field analyses from farmlands in England, and 48% of participants' fields and the research experiment showed no evidence for earthworms being widespread and/or the presence of all three ecological groups of earthworms. A Spring 2019 survey generated earthworm population data from farmland soils around the world, amassing 11,464 earthworms assessed
over 2,200 ha in the UK. A total of 12 scientists (from 30 questionnaire invitations) volunteered their time and expertise to support the survey. Conclusions helped to
prioritise future improvements in earthworm monitoring, which should include photographs of earthworms for verification of the data, long-term monitoring and integration with soil properties. Most (83%) perceived this earthworm survey would
likely improve farmland soil health and so would recommend its use in the UK. The survey is being independently taken forward and used as a metric by both private and public stakeholders, demonstrating authentic knowledge transfer in soil science
Soil aggregate stability and macrofauna as indicators of soil health and sustainable agricultural systems
A healthy soil associated with sustainable crop production is likely to be considered a sustainable agricultural system. Soil health indicators only have value if they influence management decisions that support soil and food security. The surface layer (<5 cm) of a field is disproportionally affected by arable land management practices. For silty-clay soils, structural degradation of this layer leads to slaking under the impact of rain, with implications for nutrient leaching, capping, crop emergence, infiltration, runoff and erosion. Thus, aggregate stability (rapid wetting) measurements have relevance for both soil and food security. Also, earthworm activity is a major factor regulating aggregate stability, and important for both soil functions and supporting plant productivity.
Three dynamic soil health indicators, aggregate mean weight diameter, earthworm populations and Lumbricus.terrestris (indicator species) midden abundance, were measured in arable field trials. Results showed that all soils tested were unstable, contained small earthworm populations and very few L. terrestris earthworms, although the actions of the limited numbers of L. terrestris anecic earthworms, specifically their middens, were associated with high biological activity and soil aggregation, highlighting their role as an ecosystem engineer.
Contrary to expectations, organic amendments did not improve the indicators. A more fundamental change in management practices addressing tillage and/or cropping is likely to be needed to improve soil health and the sustainability of the agricultural system. Despite the indications of poor soil health, crop yields have been sustained and, in many cases, increased by appropriate nutrient management. However, these findings suggest that these agricultural systems may not be resilient to changes in rotation, climate and weather variabilit
Deterministic Secure Communications using Two-Mode Squeezed States
We propose a scheme for quantum cryptography that uses the squeezing phase of
a two-mode squeezed state to transmit information securely between two parties.
The basic principle behind this scheme is the fact that each mode of the
squeezed field by itself does not contain any information regarding the
squeezing phase. The squeezing phase can only be obtained through a joint
measurement of the two modes. This, combined with the fact that it is possible
to perform remote squeezing measurements, makes it possible to implement a
secure quantum communication scheme in which a deterministic signal can be
transmitted directly between two parties while the encryption is done
automatically by the quantum correlations present in the two-mode squeezed
state.Comment: 10 pages, 4 figure
Effective nonlinear optical properties of composite media of graded spherical particles
We have developed a nonlinear differential effective dipole approximation
(NDEDA), in an attempt to investigate the effective linear and third-order
nonlinear susceptibility of composite media in which graded spherical
inclusions with weak nonlinearity are randomly embedded in a linear host
medium. Alternatively, based on a first-principles approach, we derived exactly
the linear local field inside the graded particles having power-law dielectric
gradation profiles. As a result, we obtain also the effective linear dielectric
constant and third-order nonlinear susceptibility. Excellent agreement between
the two methods is numerically demonstrated. As an application, we apply the
NDEDA to investigate the surface plasma resonant effect on the optical
absorption, optical nonlinearity enhancement, and figure of merit of
metal-dielectric composites. It is found that the presence of gradation in
metal particles yields a broad resonant band in the optical region, and further
enhances the figure of merit.Comment: 20 pages, 5 figure
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