The main objective of this work was to design a novel device for compaction of metal powders so that the green parts could be ejected with applying a negligible force and without the need for any lubricant in either an admixed form or applied to the die wall. For this purpose a 40 mm diameter one-piece die was envisaged which would elastically contracted 0.076 mm before compaction and after com...

The compaction of soils used for crop production is becoming an increasingly important consideration in South Africa following the shift towards reduced tillage and increased mechanisation of in-season operations and harvesting. The intensification of dairying has also been found to have a deleterious effect on soil quality, particularly in terms of compaction by trampling, which results in los...

Soil compaction reduces rooting, infiltration, water storage, aeration, drainage, and crop growth. Soil compaction has been studied intensively for more than a century, and yet we still struggle with the effect that soil compaction has on crop production and the environment. In this article, we attempt to present the primary causes of soil compaction including trafficking weak soil, excessive l...

Stream compaction is an important parallel computing primitive that produces a reduced (compacted) output stream consisting of only valid elements from an input stream containing both invalid and valid elements. Computing on this compacted stream rather than the mixed input stream leads to improvements in performance, load balancing, and memory footprint. Stream compaction has numerous applicat...

First posted March 3, 2022 For additional information, contact: Director, Integrated Modeling and Prediction DivisionWater Mission AreaU.S. Geological Survey12201 Sunrise Valley Dr., MS 411Reston, VA 20192-0002Contact Pubs Warehouse This report describes the skeletal storage, compaction subsidence (CSUB) package of MODFLOW 6. The CSUB simulates vertical compressible sediments land subsidence. g...

Effective management of nitrateimpacted aquifers requires identifying the sources of nitrate to the aquifer, and understanding the transport and fate of nitrate within the aquifer. Source identification is crucial to effective source mitigation; conversion of residential septic systems to sewer in a rural community will be ineffective if the primary source of nitrate contamination is agricultur...

The vulnerability of public supply wells to chlorinated ethene (CE) contamination in part depends on the availability of naturally occurring organic carbon to consume dissolved oxygen (DO) and initiate reductive dechlorination. This was quantified by building a mass balance model of the Kirkwood-Cohansey aquifer, which is widely used for public water supply in New Jersey. This model was built b...

The invasion of DNAPL into fractured low permeability deposits results in the formation of secondary source zones that represent a long-term source of VOCs to adjacent aquifers. We present data from a site underlain by a fractured mudstone contaminated with TCE DNAPL that was poised for release following remediation of the overlying aquifer. Observations of contaminant distributions and fractur...