Bulk Density Of Media Research Articles

Effects of Rock Covering on Underlying Engineered Media in Bioretention Practices in Middle Tennessee, USA

AbstractBioretention practices have become a common way to protect natural waterways in urban and suburban landscapes across the United States. However, optimal design, implementation, operation, and maintenance are still in need of study. A field survey of 52 bioretention practices was conducted in Davidson County, Tennessee, to address research questions related to operation and maintenance. A suite of site conditions were documented, such as size, signs of erosion, and dominant surface cover. Samples were collected from the surface of the engineered media layer and analyzed for organic matter content and bulk density. Vegetation was described in terms of dominant species and canopy cover. On average, the organic matter content of media under plant‐based mulch cover was significantly greater than that under rock cover (p = 0.002). Bulk density of the surface media is strongly and inversely correlated to organic matter content; bulk density did not generally vary with bioretention area age and was highly variable within treatments. On average, the bulk density of the media under the plant‐based mulch cover was significantly less than that under the rock cover. Media under the composite treatments had similar bulk density to both the plant‐based mulch (p = 0.233) and the rock covers (p = 0.132). Plant canopy did not surpass 70% in practices with bulk density values above 1.55 g/cm3. These results suggest that consideration should be made regarding the tradeoffs between utilizing rock coverings and potential for plant establishment impacts.

Evaluation of the Physical Characteristics and Chemical Properties of Black Soldier Fly (Hermetia illucens) Larvae as a Potential Protein Source for Poultry Feed.

The aim of this study was to investigate and compare the effects of different drying methods on the physical and chemical properties of black soldier fly larvae (BSFL) to determine their potential as an alternative protein source in animal feed. The experimental design was a 2 × 3 factorial arrangement in a completely randomized design (BSFL type × drying method), with five replications. The influence of post-harvest procedures was studied, including the different BSFL types (non-defatted and defatted) and drying methods (parabola dome, hot air oven, and microwave). The results showed that the types of BSFL, drying methods, and their interaction significantly (p < 0.001) influenced the feed's physical properties; these included the brightness of color (L* 29.74-54.07; a* 0.40-5.95; b* 9.04-25.57), medium bulk density (381.54-494.58 g/L), free flow with an angle of repose (41.30-45.40°), and small particle size. They significantly (p < 0.001) influenced the nutritive value of BSFL, which contained 42-59% crude protein, 7-14% crude fiber, 9-30% ether extract, and 5035-5861 kcal/kg of energy. Overall, both BSFL types and all the drying methods resulted in a slight variation in the proximate composition. However, a microwave and a hot-air oven were considered the most suitable methods for producing BSFL powder because of the high levels of nutrients retained and the improved physical parameters when compared to a parabola dome. This characterization of the physical and chemical composition of BSFL represents a preliminary methodology that could be used to initially preprocess larvae for use as an alternative protein source in animal feed and for other applications.

Experimental investigation on the smoldering limit of scraps of paper initiated by a cylindrical rod heater

The ignition temperature for smoldering in scraps of paper has been determined experimentally for several bulk densities under different external air flows. Beds of compressed scraps of paper were packed into a vertical combustion chamber to achieve different bulk densities and the temperature of an electrically set rod-heater was heated to temperatures between 350 and 450 °C. Once the rod-heater had reached the set temperature, the electric current supply was then turned off and the heater was embedded into the middle of the vertical combustion chamber filled with a packed bed of paper scraps. We obtained the ignition limit of the scraps of paper for different bulk densities under different external air flows by recording the temperature evolution at different positions in the combustion chamber. Results show that without external air flow, the ignition temperature first decreased with an increase in bulk density, then after a critical value, an increase in bulk density led to an increase in the ignition temperature. Furthermore, we found that even under a quiescent case (without external air flow), for the cases where ignition occurred, the smoldering front first reached the bottom side of the combustion chamber, then propagated to the upper side. As for cases with external air flows, again the propagations of the smoldering front towards the bottom side of the combustion chamber were observed in the cases where ignition happened, and external air flows played different roles in ignition limit of paper scraps bed with low bulk density, medium bulk density and high bulk density regime, respectively.

Assessing the Effects of Bioretention’s Engineered Media Composition and Compaction on Hydraulic Conductivity and Water Holding Capacity

AbstractBioretention devices are often recognized as stormwater control measures (SCMs) that satisfy green infrastructure or low-impact development (LID) objectives. The hydraulic characteristics of filter media underpin effective bioretention performance. Successful design criteria compiled from international design guidelines were used to create a range of engineered media subjected to two compaction methods and various configurations of media compositions and ponding depth. Experimental treatments of particle size distribution (PSD), organic content and composition, and aggregate content and source were combined to quantify their effects on media saturated hydraulic conductivity Ks and water holding capacity. The PSD alone was not an effective indicator of potential Ks; a target Ks of 12.5–150 mm/h (corresponding to 2–24 h drawdown from 300-mm ponding depth) was infeasible using PSD recommendations with locally available materials. Bulk density of media with only 30% sand and >30% v/v organic content ...

Geotechnical Maps of West and Pump Canals and their Branches of the Southern Jazirah Irrigation Project – NW Iraq

The main object of this work is to establish some of geotechnical maps of western canal, the pumping canal and their branches in the Southern Jazirah Irrigation project NW Iraq. Data have been collected, with different depths, from the drilled 218 boreholes. The data divided into three zones depending on the depth of each zone 5 meters, the first one is 0-5 m., the second is 5-10m. and the third is 10-15m. The mean values of engineering properties, represented by Atterberg limit (Liquid limit, Plastic limit And Plasticity index) and bulk density have been adopted as basis to prepare these maps.. The purpose of this division is to ensure information about these properties especially, for construction and agriculture purposes in order to helps designer in distribution of small and large constructions all over the project. The results show that the mean value of plasticity index reached 25 which is vital in ensuring non disturbance in soil while packing. The soil is characterized with swelling and shrinkage potential by having liquid limit rang between (40-50) and plastic limit between (30-20). Liquid limit and plasticity index have been used in soil classification of each zone. To illustrate the distribution of these properties SURFER program has been utilized. The engineering –geological maps show that the distribution of most engineering properties tends to improve towards west and south west of the project, except that the medium bulk density in site of pump stations which are deemed the best density for establishing such stations .Whereas the values of the bulk density were between low to very low in the whole project, whereof such bulk are useful in agricultural purposes because of the tendency of its water absorption and the reduction in surface runoff.

Automotive hydrogen storage system using cryo-adsorption on activated carbon

An integrated model of a sorbent-based cryogenic compressed hydrogen system is used to assess the prospect of meeting the near-term targets of 36 kg-H2/m3 volumetric and 4.5 wt% gravimetric capacity for hydrogen-fueled vehicles. The model includes the thermodynamics of H2 sorption, heat transfer during adsorption and desorption, sorption dynamics, energetics of cryogenic tank cooling, and containment of H2 in geodesically wound carbon fiber tanks. The results from the model show that recoverable hydrogen, rather than excess or absolute adsorption, is a determining measure of whether a sorbent is a good candidate material for on-board storage of H2. A temperature swing is needed to recover >80% of the sorption capacity of the superactivated carbon sorbent at 100 K and 100 bar as the tank is depressurized to 3–8 bar. The storage pressure at which the system needs to operate in order to approach the system capacity targets has been determined and compared with the breakeven pressure above which the storage tank is more compact if H2 is stored only as a cryo-compressed gas. The amount of liquid N2 needed to cool the hydrogen dispensed to the vehicle to 100 K and to remove the heat of adsorption during refueling has been estimated. The electrical energy needed to produce the requisite liquid N2 by air liquefaction is compared with the electrical energy needed to liquefy the same amount of H2 at a central plant. The alternate option of adiabatically refueling the sorbent tank with liquid H2 has been evaluated to determine the relationship between the storage temperature and the sustainable temperature swing. Finally, simulations have been run to estimate the increase in specific surface area and bulk density of medium needed to satisfy the system capacity targets with H2 storage at 100 bar.

Relation between Growth and Vertical Distribution of Fine Roots and Soil Density in the Weibei Loess Plateau

The influence of woodland soil bulk density on the growth and distribution of fine root system of main planting tree species in the Weibei Loess Plateau was investigated by means of pot culture and field survey. Results indicated that in the woodland of Pinus tabulaeformis, soil bulk density increased with the depth at different sites, while in the woodland of Robinia pseudoacacia, soil bulk density was higher than that in P. tabulaeformis, and there was no clear difference across the profile. Further analysis implied that there existed negative correlations between soil bulk density and fine root length in the woodland of P. tabulaeformis. Results from pot culture indicated that although the effects of pot culture media on the fine root growth and development of different tree species seedlings were different, all treated seedlings grew better in the soil matter with medium bulk density and porosity and with the biggest biomass. Bulk density of pot culture media had clear effects on the growth and development of P. tabulaeformis and R. pseudoacacia seedling roots, especially on the former, whereas it had little effect on that of Platycladus orientalis and Prunus armeniaca var. ansu, whose fine root biomass changed little in different pot culture media.

Root and shoot growth ofProsopis chilensisin response to soil impedance and soil matric potential

The suitability ofProsopis chilensisfor reforestation under conditions of high soil bulk density and high moisture stress was examined in a greenhouse study at the University of California, Riverside. Root growth was greatly reduced at high bulk density (2.1 Mg m−3) and high moisture stress (−1.0 MPa). However, adverse effects of high bulk density were greatly reduced at low moisture stress. Rate of root growth was adequate for good tree establishment in soils with medium bulk density (1.7 Mg m−3).Prosopis chilensiscould be successfully grown on dense soils provided good moisture conditions were available for sufficient time.

Physical and Chemical Properties of Media Suitable for Containerized Bare Root Whip Production

Abstract Moisture retention characteristics, pH, cation exchange capacity (CEC) and bulk density of media suitable for containerized bare root whip production and the effects of these media on red oak (Quercus rubra L.) and blackgum (Nyssa sylvatica Marsh.) growth were studied. Media tested were: 3:1:1, 2:1:2 and 2:2:1 (by vol) sand:composted municipal sewage sludge [Comtil]:Isolite or zeolite. A similar series of media were prepared by substituting rice hulls for sand. Similar physical properties were determined for three media components: rice hulls, Comtil and pine bark. Rice hulls and Comtil had high water retention at container capacity, 70.1 and 85.4%, respectively. Thus, substituting rice hulls for sand increased media water retention at container capacity and total plant available water. Media pH ranged from 4.9 (2:1:2 and 2:2:1 rice hulls:Comtil:zeolite) to 6.3 (3:1:1 sand:Comtil:zeolite). Rice hulls and Comtil had bulk densities similar to pine bark (0.30 and 0.32, respectively vs. 0.35 g cm−3); thus, medium bulk density was lower when rice hulls were substituted for sand. Rice hull-based media cation exchange capacity was higher than sand-based media. There were no differences in red oak height growth in the different media; height growth averaged 72 cm (28 in). Blackgum height was greatest (138 cm, 54 in) in 2:2:1 rice hull:Comtil:zeolite medium. The results demonstrate that rice hulls could be substituted for sand without reducing height growth of either species. When grown in the different bare root media, red oak and blackgum seedlings could be bare rooted by hand shaking. The root systems of both species were fibrous with many roots with intact root tips.

Hydrophilic Polymers—Their Response to Soil Amendments and Effect on Properties of a Soilless Potting Mix

The levels of hydration of several hydrophilic polymers (hydrogels) varied greatly. Starch-based polymers had the fastest rate of hydration (&lt;2 hours), followed by a propenoate-propenamide copolymer. Polyacrylamide materials required 4 to 8 hours to become fully hydrated. Maximum water retention in distilled water varied from 400 to 57 g of water per gram of dry material. All hydrogels retained less water in the presence of metal ions or fertilizers in the soaking solution, with substances releasing Fe+2 being the most detrimental. After exposure to fertilizers and ions, the water-holding capacity of a polyacrylamide with a high degree of cross linkage, but not that of hydrogels of the other structures, was fully recovered by subsequently soaking in distilled water. Pots amended with a polyacrylamide polymer but without Micromax (a micronutrient source) reached maximum water retention after six irrigations, while those with Micromax required 10 irrigations to reach peak water retention. The amounts of water being held in pots decreased after repeated fertilization. Medium volume increased with increasing levels of the polyacrylamide Supersorb C (0, 2, 4, or 6 g/pot). Micromax incorporated in medium amended with Supersorb C caused a depression in volume. Medium bulk density, total water retention, and water retention per unit volume of medium were increased by the incorporation of the hydrogel, regardless of the presence of Micromax. Noncapillary porosity measured at container capacity in medium amended with Micromax progressively decreased as the amount of hydrogel increased, but remained unchanged in medium without Micromax. Repeated drying and dehydration of the medium resulted in reduced water retention and increased noncapillary pore space.

NATURE OF HYDR0PHILIC POLYMERS AND THEIR EFFECT ON SOIL PROPERTIES

The rate of full hydration for several hydrophilic polymers differed greatly (starch-based polymers &gt; propenoate-propenoamid copolymer &gt; polyacrylamide). Maximum water retention in distilled water varied from over 500 g to 57 g of water per of different dry materials. All polymers retained less water in the presence of metal ions or fertilizers, with substances releasing Fe+2 being the most detrimental. Potting media containing a polyacrylamide polymer reached maximum water retention after 6 irrigations, while those with Micromax (micronutrient source) required 10 irrigations to reach maximum hydration. The water-holding capacities of the media declined after repeated fertilization. Medium bulk density, total watet retention, and water retention per unit volume of medium were increased by the incorporation of the polymer, regardless of the presence of Micromax. Non-capillary porosity in medium amended with Micromax progressively decreased as the amount of the polymer increased, but remained unchanged in medium without Micromax. Repeated wet-dry cycles resulted in decreased water retention and increased non-capillary pore space of the media.

Physical Properties of Media Composed of Peanut Hulls, Pine Bark, and Peatmoss and their Effects on Azalea Growth1

Abstract Equal volumes of peanut hulls, pine bark, and sphagnum peatmoss were combined into 5 media. Particle size distribution, total porosity, air space, easily available water, water buffering capacity, and bulk density were determined for each medium. Top dry weight, root dry weight, and percent growth of Rhododendron indicum (L.) Sweet cv. George L. Taber were measured 14 weeks after potting in 1-liter containers. Peanut hulls increased particle size, total porosity, and air space, and decreased easily available water, water buffering capacity, and bulk density of media. Peatmoss generally reduced total porosity and air space and increased easily available water, water buffering capacity, and bulk density regardless of other component combinations. Top dry weight, root dry weight, and percent growth were greater in peanut hull-containing media. Addition of peatmoss to the container media tended to produce less growth.