Relevant bibliographies by topics / Relative compaction

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Academic literature on the topic 'Relative compaction'

Author: Grafiati
Published: 4 June 2021
Last updated: 1 February 2022

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Journal articles on the topic "Relative compaction"

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CARTER, M. R. "RELATIVE MEASURES OF SOIL BULK DENSITY TO CHARACTERIZE COMPACTION IN TILLAGE STUDIES ON FINE SANDY LOAMS." Canadian Journal of Soil Science 70, no. 3 (August 1, 1990): 425–33. http://dx.doi.org/10.4141/cjss90-042.

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Field studies concerned with soil physical properties require methods to quantify and characterize soil compaction, especially for tillage experiments. The bulk densities of a Charlottetown and Gowanbrae fine sandy loam were related to a maximum or standard compaction state for each soil to obtain a measure of relative compaction. The two soils were both classified as Orthic Humo-Ferric Podzols. Relative compaction was closely related to the volume of macropores (r2 = 0.85). Over a 3-yr period, mouldboard ploughing loosened the soil to give an average relative compaction of 77%. Subsequent soil consolidation and settling increased relative compaction to 84% over the growing season. Direct-drilling maintained relative compaction at a limited range of 88–91%. Relative grain yield of cereals was related (r2 = 0.69) using a polynomial curve to relative compaction. A range of 77–84% relative compaction was associated with a relative grain yield ≥ 95%. A relative compaction of 84–89% was considered the equilibrium soil density level for the two soils under study. This range was related to a macropore volume of 13.5–10% which is adequate for permeability but possibly inadequate for optimum soil aeration under a humid soil moisture regime. Overall, relative compaction provided a useful index or standard to assess changes in soil bulk density and proved to be a biologically meaningful soil physical parameter. Key words: Soil compaction indices, relative compaction, Podzolic soil, fine sandy loam, cereal yield
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Voicu, Gheorghe, Mircea Lazea, Gabriel-Alexandru Constantin, Elena-Madalina Stefan, and Mariana-Gabriela Munteanu. "Finite element analysis of the compaction plate from a garbage truck." E3S Web of Conferences 180 (2020): 04006. http://dx.doi.org/10.1051/e3sconf/202018004006.

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Vehicles that collect and transport household waste are equipped with complex systems that perform the loading of the waste from the stationary collection containers, take over and pre-compact of material, compaction in the body of the structure and finally the landfill of the collected waste. Of all these operations, the compaction process is by far the most mechanically demanding. In this paper, the structural analysis of the compactor plate from a garbage truck is presented. In the first stage it was carried out parametric modelling of the assembly composed of compactor plate, counter pressure plate, the back of the garbage truck and to be compacted material. After assembly, the dynamic simulation of the compaction process in the garbage truck was performed, and the compaction mechanical stresses for the compactor plate were loaded in the Simulation module of the SolidWorks 2016 program. Here the finite element analysis was performed, resulting in the value and dispersion of the equivalent stresses (calculated by von Mises criterion), displacements and relative deformations of compactor plate from the analysed garbage truck.
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Mohammadi, K., and Abolfazl Darvizeh. "Dynamic Model of Compaction Process of Metallic Powders." Advanced Materials Research 264-265 (June 2011): 155–59. http://dx.doi.org/10.4028/www.scientific.net/amr.264-265.155.

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Dynamic modeling of compaction process ,and evaluation of hardening parameters of powder compacts undergoing uni-axial/multi compaction is a tedious process and requires many elaborate tests .However ,assuming a two-parameter failure surface ( such as Mohr–Coulomb),evolution of failure surface may be monitored by two points on the failure surface. Results of uni-axial compression and direct or indirect tensile tests may readily provide the two required points. In order to assess this hypothesis ,a laboratory investigation was carried out using atomized iron powder(WPL-200) and aluminum powder(+160Mm) . Green compacts of the said drop-hammer , specifically designed for this purpose. Specimens with various relative compactions were produced and tested in uni-axial compression test and Brazilian split test .Variations of compressive/tensile strength with compaction energy(hammer speed) and relative density were studied and hardening law for green compacts were developed.
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Qian, Jing, and Ling Wei Meng. "Structural Analysis for Space-Swing Mechanism on Gyratory Compactor." Key Engineering Materials 621 (August 2014): 253–59. http://dx.doi.org/10.4028/www.scientific.net/kem.621.253.

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Based on the automatic dynamic analysis of mechanical systems software, both rigid and flexible models of the space-swing mechanism for the superpave gyratory compactor are developed. The structural analysis shows that the length and the initial phase of cranks, and the assembling accuracy (coordinates) of some points are very sensitive relative to the waving of compaction angle. Greater rigidity helps stabilize the change of the compaction angles.
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Day, Robert W. "Relative Compaction of Fill Having Oversize Particles." Journal of Geotechnical Engineering 115, no. 10 (October 1989): 1487–91. http://dx.doi.org/10.1061/(asce)0733-9410(1989)115:10(1487).

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Han, P., X. Z. An, Y. X. Zhang, and Z. S. Zou. "FEM modeling on the compaction of Fe and Al composite powders." Journal of Mining and Metallurgy, Section B: Metallurgy 51, no. 2 (2015): 163–71. http://dx.doi.org/10.2298/jmmb150210020h.

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The compaction process of Fe and Al composite powders subjected to single action die compaction was numerically modeled by FEM method. The relationship between the overall relative density and compaction pressure of the compacts with various Al contents was firstly identified, and the influences of Al content on the local relative density, stress, and their distributions were studied. Then the compaction pressure effects on the above properties with fixed Al content were discussed. Furthermore, detailed flow behaviors of the composite powders during compaction and the relationship between the compaction pressure and the ejection force/spring back of the compact were analyzed. The results show that: (1) With each compaction pressure, higher relative density can be realized with the increase of Al content and the relative density distribution tends to be uniform; (2) When the Al content is fixed, higher compaction pressure can lead to composite compact with higher relative density, and the equivalent Von Mises stress in the central part of the compact increases gradually; (3) Convective flow occurs at the top and bottom parts of the compact close to the die wall, each indicates a different flow behavior; (4) The larger the compaction pressure for each case, the higher the residual elasticity, and the larger the ejection force needed.
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Güner, Faruk. "Numerical Investigation of AISI 4140 Powder High Relative Density Compaction In Terms of Compaction Velocity." Mechanics 26, no. 1 (February 12, 2020): 5–11. http://dx.doi.org/10.5755/j01.mech.26.1.22862.

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In this study high relative density compaction of AISI 4140 steel powder compaction numerically investigated via different compaction velocities using Multi Particle Finite Element Method (MPFEM). 2D Analyses performed by three different particle geometry; 25µm, 35µm and 45µm in radius. Particle size effect also investigated via high relative density and compaction velocity. von Mises Power law evaluated for AISI 4140 steel powder and utilized to analysis. Results were plotted both in visually and graphically in aim to show effect of relative density, particle size, contact interactions and compaction velocity. The stress distribution through the height of die revealed out. A four-fold increase in compaction velocity increase the Equivalent von Mises stress 2% where the stress value can reach up to 3 times the yield stress. Stress values along the punch to the bottom of the die show a parabolic tendency with compaction velocity increase.
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Ngai, Tungwai Leo, Zhi Yu Xiao, Yuan Biao Wu, and Yuan Yuan Li. "Studies on Preparation of Ti3SiC2 Particulate Reinforced Cu Matrix Composite by Warm Compaction and Its Tribological Behavior." Materials Science Forum 534-536 (January 2007): 929–32. http://dx.doi.org/10.4028/www.scientific.net/msf.534-536.929.

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Conventional powder metallurgy processing can produce copper green compacts with density less than 8.3 g/cm3 (a relative density of 93%). Performances of these conventionally compacted materials are substantially lower than their full density counterparts. Warm compaction, which is a simple and economical forming process to prepare high density powder metallurgy parts or materials, was employed to develop a Ti3SiC2 particulate reinforced copper matrix composite with high density, high electrical conductivity and high strength. In order to clarify the warm compaction behaviors of copper powder and to optimize the warm compaction parameters, effects of lubricant concentration and compaction pressure on the green density of the copper compacts were studied. Copper compact with a green density of 8.57 g/cm3 can be obtained by compacting Cu powder with a pressure of 700 MPa at 145°C. After sintered at 1000°C under cracked ammonia atmosphere for 60 minutes, density of the sintered compact reached 8.83 g/cm3 (a relative density of 98.6%). Based on these fabrication parameters a Ti3SiC2 particulate reinforced copper matrix composite was prepared. Its density, electrical conductivity, ultimate tensile strength, elongation percentage and tribological behaviors were studied.
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Landrø, Martin, and Jan Stammeijer. "Quantitative estimation of compaction and velocity changes using 4D impedance and traveltime changes." GEOPHYSICS 69, no. 4 (July 2004): 949–57. http://dx.doi.org/10.1190/1.1778238.

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In some hydrocarbon reservoirs, severe compaction of the reservoir rocks is observed. This compaction is caused by production, and it is often associated with changes in the overburden. Time‐lapse (or 4D) seismic data are used to monitor this compaction process. Since the compaction causes changes in both layer thickness and seismic velocities, it is crucial to distinguish between the two effects. Two new seismic methods for monitoring compacting reservoirs are introduced, one based on measured seismic prestack traveltime changes, and the other based on poststack traveltime and amplitude changes. In contrast to earlier methods, these methods do not require additional empirical relationships, such as, for instance, a velocity‐porosity relationship. The uncertainties in estimates for compaction and velocity change are expressed in terms of errors in the traveltime and amplitude measurements. These errors are directly related to the quality and repeatability of time‐lapse seismic data. For a reservoir at 3000‐m depth with 9 m of compaction, and assuming a 4D timeshift error of 0.5 ms at near offset and 2 ms at far offset, we find relative uncertainty in the compaction estimate of approximately 50–60% using traveltime information only.
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Yu, Bangyong, Shucai Pan, and Kaisheng Xu. "Particle Crushing and Morphology Evolution of Saturated Crushed Gangue under Compaction." Advances in Civil Engineering 2020 (November 11, 2020): 1–10. http://dx.doi.org/10.1155/2020/8839302.

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In this research, the deformation, particle crushing, and morphology evolution of saturated crushed gangue under variable axial stresses (0, 2, 4, 8, 12, 16, and 20 MPa) were investigated by performing a series of laboratory tests with our self-designed compacting device. The research results showed that the relationship between compression modulus and axial stress can be expressed by an exponential function. The relative breakage varied from 0 to 0.3685 and increased monotonously with the increase of axial stress. The relation between relative breakage and axial strain was described by a linear function. The particle circularity varied from 1.179 to 1.361 and decreased gradually with the increase of axial stress. When the axial stress increased from 0 MPa to 2 MPa, the relative breakage increased rapidly by over 39.15% of the total increase, and the particle circularity of large particles in the range of 15–20 mm sharply decreased by over 48.34% of the total decrease. 2 MPa was a key value in controlling the particle crushing of the saturated crushed gangue during compaction. Particle crushing was predominantly divided into three types: fracture, crushing, and grinding. At the early stage of compaction, fracture and crushing took place in large numbers. At the end, grinding was the main form of particle crushing. The axial strain was influenced by the initial gradation, and a larger Talbot exponent corresponded to a larger strain. However, the initial gradation had little effect on the relative breakage.
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Dissertations / Theses on the topic "Relative compaction"

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Zhao, Yihai (Simon). "Relative bulk density as an index of soil compaction and forest productivity in British Columbia." Thesis, University of British Columbia, 2009. http://hdl.handle.net/2429/10318.

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Soil compaction often limits conifer regeneration on sites degraded by construction of landings and roads, but inadequate understanding of compaction characteristics has sometimes led to inappropriate rehabilitation efforts. This warrants development of new methods to assess compaction and its relation to tree growth. The objective of this study was to develop a high-level integration indicator that will characterize compaction of forest soils and that could be correlated to tree height growth. Mineral particle density of soils from interior British Columbia (BC) forests varied significantly among the geographic locations. Oxalate-extractable Fe- and Al-oxides and particle size distribution (PSD) were related to soil and mineral particle densities, while soil organic matter (SOM) and Al- and Fe-oxides were important soil properties in relation to soil particle density. The significance of levels of single soil properties in predicting maximum bulk density (MBD) were in the order: plastic and liquid limits, organic matter content, oxalate-extractable oxide, and PSD. Stratification of the sample according to Atterberg limits improved the predictability of MBD, and variation in particle density was included in the prediction by other soil properties used in the models. Height growth of interior Douglas-fir (Pseudotsuga menziesii var. glauca [Bessin] Franco) was restricted when relative bulk density (RBD) was > 0.72. For lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) and hybrid white spruce (Picea glauca [Moench] Voss × engelmannii Parry ex Engelm.), an RBD of 0.60 - 0.63 corresponded to maximum height growth, while that of 0.78 - 0.84 appeared to limit height growth. The presence of surface organic material mitigated compaction and was often associated with lower RBD. Interior Douglas-fir and lodgepole pine planted in low elevation sites in north-central BC did not grow well and their height growth was weakly related to RBD. The results suggest that soil rehabilitation should be considered on disturbed sites where soil RBD is > 0.80. Findings in this study have implications in assessing forest soil compaction and its effect on site productivity. The results will help predict soil behaviour and associated tree growth in response to timber harvesting and site rehabilitation.
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Strassburg, Alec N. "Influence of Relative Compaction on Passive Resistance of Abutments with Mechanically Stabilized Earth (MSE) Wingwalls." BYU ScholarsArchive, 2010. https://scholarsarchive.byu.edu/etd/2593.

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Large scale static lateral load tests were completed on a pile cap with wingwalls under several different sand backfill configurations: no backfill, loosely compacted unconfined, loosely compacted slip plane wall confined, loosely compacted MSE wingwall confined, and densely compacted MSE wingwall confined. The relative compaction of the backfill was varied during each test to observe the change in passive resistance provided by the backfill. The wall types were varied to observe the force placed on the walls and the wall displacement as a result of the laterally loaded pile cap and backfill relative compaction. Passive force-displacement curves were generated from each test. It was found that the densely compacted material provided a much greater passive resistance than the loosely compacted material by 43% (251 kips) when confined by MSE walls. The outward displacement of the MSE walls decreased noticeably for the dense MSE test relative to the loose MSE test. Backfill cracking and heave severity also increased as the relative compaction level of the backfill increased. As the maximum passive force was reached, the reinforcement reached their peak pullout resistance. Correlations were developed between the passive pressure acting on the pile cap and the pressure measured on the MSE wingwalls as a function of distance from the pile cap for both loose and dense backfills. The pressure measured on the wingwalls was approximately 3 to 9% of the pressure acting on the pile cap. As the distance from the pile cap increased, the pressure ratio decreased. This result helps predict the capacity of the wingwalls in abutment design and the amount of allowable wall deflection before pullout of the backfill reinforcement occurs. Three methods were used to model the measured passive force-displacement curves of each test. Overall, the computed curves were in good agreement with the measured curves. However, the triaxial soil friction angle needed to be increased to the plane strain friction angle to accurately model both the loose and dense sand MSE and slip plane wall confined tests. The plane strain friction angle was found to be between 9 to 17% greater than the triaxial friction angle.
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Michener, John E. "Effects of Environmental Factors on Construction of Soil-Cement Pavement Layers." Diss., CLICK HERE for online access, 2008. http://contentdm.lib.byu.edu/ETD/image/etd2630.pdf.

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Seymour, Louise. "The role of moisture profiling towards understanding pharmaceutical solid state functionality : validation and the application of a moisture profiling analytical tool for investigation into the characterisation of, and prediction of, the effects of compaction and storage on different lactose physical forms." Thesis, University of Bradford, 2015. http://hdl.handle.net/10454/15321.

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The majority of therapeutic pharmaceutical formulations are presented in the solid form. Moisture is able to play an important role in the functional performance of pharmaceutical solids. Moisture profiling is able to provide novel information with regards to the behaviour of moisture within materials using equilibrium relative humidity as a measurement. The hypothesis investigated explores the changes in equilibrium relative humidity of pharmaceutical material induced by physical, chemical or storage conditions, these are able to be monitored using the innovative moisture profiler system. The aims within this were to primarily validate the moisture profiler and secondly evaluate the effects of moisture on physical forms and with respect to effects of compaction, finally this was compared to conventional characterisation methods. Preliminary explorations were conducted in order to assess the validity of the moisture profiler, from this lactose was selected as a suitable pharmaceutical material for further work. Processing effects were then examined, firstly storage at elevated relative humidity of different forms of lactose were explored, and this was carried out with supplementary analysis. Secondly the effects of tabletting were explored, different compaction forces were investigated to observe if this had any notable effects on equilibrium relative humidity of the different lactose forms. Finally subsequent storage of the compacts were examined in order to explore if there were any changes in the equilibrium relative humidity.
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Azhdar, Bruska. "Improved high velocity cold copaction processing : polymer powder to high performance parts." Licentiate thesis, KTH, Polymer Technology, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-407.

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A uniaxial High-Velocity Compaction (HVC) process for polymer powder using a cylindrical, hardened steel die and a new technique with relaxation assist was tested with a focus on the compactibility characteristics and surface morphology of the compacted materials using various heights of relaxation assist device with different compacting profiles.

Relaxation assist device was presented as a new technique to reduce springback, pull-out phenomenon and to improve the compaction process.

The basic phenomena associated with HVC are explained and the general energy principle is introduced to explain pull-out phenomenon during the decompacting stage. In this study, polyamide-11 powders with different particle size distributions have been compacted with the application of different compaction profiles, e.g. different energies and velocities. It was found that the relative green density is influenced more by the pre-compacting (primary compaction step) than by the post-compacting (secondary compaction step).

Experimental results for different compaction profiles were presented showing the effect of varying the opposite velocity during the decompacting stage and how to improve the homogeneous densification between the upper and lower surface and the evenness of the upper surface of the compacted powder bed by using relaxation assists, and the influences of the relaxation assist device on the process characteristics. It was found that the relaxation assist improves the compaction of the polymer powder by locking the powder bed in the compacted form. In addition, the relative times of the compacting stage, decompacting stage and the reorganisation of the particles can be controlled by altering the height of the relaxation assist. It was found that the high-velocity compaction process is an interruption process and that the delay times between the pressure waves can be reduced by increasing the height of the relaxation assist device. Furthermore, the first gross instantaneous springback and the total elastic springback are reduced.

Two bonding strain gauges and a high-speed video camera system were used to investigate the springback phenomenon during the compaction process. Scanning electron microscopy (SEM) and image computer board Camera (IC-PCI Imaging Technology) were used to the study the morphological characteristics, the limit of plastic deformation and particle bonding by plastic flow at contact points, and pull-out phenomena.


QC 20100506
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Soman, Anand Vaidyanathan P. P. "New results on paraunitary filter banks : energy compaction properties, linear phase factorizations and relation to wavelets /." Diss., Pasadena, Calif. : California Institute of Technology, 1993. http://resolver.caltech.edu/CaltechETD:etd-10202005-094027.

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Tubeileh, Ashraf. "Photosynthèse, répartition des assimilats et rhizodéposition chez le maïs (Zea Mays L. ) soumis à la compaction du sol." Vandoeuvre-les-Nancy, INPL, 2000. http://docnum.univ-lorraine.fr/public/INPL_T_2000_TUBEILEH_A.pdf.

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L'objectif de ce travail a été d'étudier l'effet de la compaction du sol sur l'activité photosynthétique, la répartition des assimilats et la morphologie du maïs en phase de croissance végétative, jusqu'à la sortie de la panicule mâle. Nous nous sommes en particulier intéressés à la rhizodéposition du carbone et à ses conséquences sur la biomasse microbienne du sol. Nous avons comparé des plantes cultivées dans des pots contenant un mélange de terre et de sable (2/1) présentant deux densités apparentes : 1,45 g cm-3 pour le sol compacté et 1,30 g cm-3 pour le témoin. Les expériences ont été conduites dans un phytotron pendant 21 à 42 jours. La répartition du carbone a été établie à l'aide des techniques de marquage court au 14 C. La densité apparente élevée du sol induit une diminution de l'activité photosynthétique et de la quantité de carbone fixée. La compaction du sol provoque un ralentissement du rythme d'émission foliaire, réduisant ainsi la hauteur des plantes, la biomasse des parties aériennes et la surface foliaire. La biomasse et la longueur racinaires sont inférieures chez les plantes subissant la compaction du sol. Simultanément, une forte augmentation de la rhizodéposition est observée dans le sol compacté. Ainsi, la biomasse microbienne du sol augmente fortement grâce à l'abondance de substrats, carbonés et à la protection physique que la compaction assure à la microflore en réduisant la porosité du sol. Pour expliquer ces résultats, nous avons émis trois hypothèses : 1- une diminution du potentiel hydrique ou une limitation de la force de puits. Des racines est à l'origine de la baisse de l'activité photosynthétique, 2- l'expansion du diamètre racinaire permet de surmonter la résistance du sol à la pénétration et 3- l'augmentation de la libération du carbone dans le sol réduit les effets de la contrainte mécanique. Les effets de la compaction persistent avec l'âge des plantes bien qu'ils diminuent en termes de pourcentage entre les deux traitements
The objective of this work was to investigate the effects of soil compaction on carbon assimilation, photosynthate partitioning, and morphology of corn plants during vegetative growth period up to tassel initiation. We were particularly interested in carbon input into the soil and soil microbial biomass. Corn plants were grown in culture pots containing compacted soil (bulk density of 1. 45 g cm-3 ) or loose soil (bulk density of 1. 30 g cm-3). Experiments were conducted in a growth chamber and lasted for 21 to 42 days. Carbon partitioning in the plant-soil system was evaluated using 14C pulse-labeling techniques. The increase in soil bulk density decreased carbon assimilation rate and total carbon fixation. Furthermore, soil compaction delayed leaf appearance rate decreasing therefore plant height, shoot dry weight, and leaf area. In addition, root biomass and root elongation were also inferior when plants were grown in compacted soil and root length appeared to be the most sensible parameter to high soil mechanical resistance. Simultaneously, a great increase in carbon input into the soil occurred to the detriment of root carbon. Soil microbial biomass increased considerably in compacted soil thanks to this increase in carbon substrates and to physical protection provided for soil microflora as a result of the reduced porosity in compacted soil. Three hypotheses were formulated to explain these results: 1- a decrease in soil or root water potential or a sink limitation induces a down-regulation of photosynthetic activity, 2- the increase in root diameter decreases soil mechanical resistance, and 3- the increase in carbon rhizodeposition alleviates the effects of mechanical constraint. The effects of soil compaction persisted with plant age although the difference between the two treatments decreased in terms of percentage
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Fei, Yingheng, and 费颖恒. "Adsorption of emerging environmental pollutants by marine sediment in relation to sediment organic diagensis." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2012. http://hub.hku.hk/bib/B48329782.

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Ever-growing discharges of various emerging chemical contaminants are imposing a great threat of pollution to the coastal environment. Adsorption by sediment plays an essential role in the transport and fate of pollutants in the aquatic system. The sorption of emerging contaminants onto sediment is believed to be largely dependent on the sediment organic matter (SOM). In the present study, laboratory experiments were carried out on the changes of the adsorption behavior of sediment during the sediment aging and diagenesis process. A few EDCs and antibiotics were selected as the model emerging compounds for the adsorption tests. The results demonstrated that both the quantity and the quality of the SOM affected the adsorption of the model pollutants, such as 17α-ethinyl estradiol (EE2) and bisphenol A (BPA), onto the marine sediment collected from Victoria Harbour, Hong Kong. The adsorption isotherms can be well described by the linear partition model. Natural and artificial sediment with a high SOM content was incubated for 4-6 months to simulate the natural diagenesis process. The most rapid degradation of labile SOM occurred in the first 1 month or so and afterward, SOM reduction became slower. Microbial activity played an important role in SOM degradation and transformation. A rapid initial bacterial growth was observed in the sediment, followed by a slow endogenous decay. The dynamics of biomass growth and decay first transformed the labile SOM into biomass and microbial byproducts. After the exhaust of readily biodegradable SOM, the biomass decay produced humic-like substances, resulting in more refractory and condensed SOM residues in the sediment. More importantly, the degradation and transformation of SOM displayed a profound impact on the adsorption behavior of the sediment. For the selected EDCs and antibiotics, including BPA, EE2, nonylphenol (NP), phenanthrene (PHE) and tetracyclines (TCs), the adsorption capacity indicated by the partition coefficient, Kd, decreased at the beginning of SOM diagenesis. The Kd values for different chemicals recovered lately to different extents as the result of the SOM condensation and humification. All of the organic matter normalized partition coefficients, KOM, of the concerned pollutants increased considerably in the late phase of SOM diagenesis. Based on the experimental results, a general conceptual model was established to describe SOM diagenesis and its impact on chemical adsorption by the sediment. According to the model prediction, the SOM profile would become more dominated by the condensed and refractory fractions during sediment diagenesis with an increasing affinity and partition capacity for organic contaminants. Moreover, the release of adsorbed contaminants from marine sediment in the simulated digestive fluids was investigated. In general, the presence of gastric pepsin and bile salts helped the desorption of hydrophobic pollutants from the sediment into the digestive solutions. The influence of the SOM diagenetic status on chemical desorption from the sediment varied between EDCs of different chemical properties. It is apparent that aged sediment could bring more emerging pollutants into the digestive system of receiving organisms, imposing a potential risk to human health through the food chain.
published_or_final_version
Civil Engineering
Doctoral
Doctor of Philosophy
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Dowd, Jennifer L. Burghardt. "Coyote Diet and Movements in Relation to Winter Recreation in Northwestern Wyoming: Implications for Lynx Conservation." DigitalCommons@USU, 2010. https://digitalcommons.usu.edu/etd/779.

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Increased snowmobile use in mountainous terrain has been highlighted as a conservation concern for some Canada lynx (Lynx canadensis) populations. Snow compaction resulting from winter recreation may potentially facilitate access by coyotes (Canis latrans) to habitats used by lynx during winter. Increased interactions could result in either exploitation or interference competition between the two species. Two recent, yet geographically distinct, studies showed contrasting findings regarding coyote movements and their use of snow-compacted trails during the winter. These findings suggest coyote association with snow-compacted trails may be regionally specific and dependent upon ecosystem dynamics and snow characteristics. The objectives of this study were to document diet, space use, and movements of coyotes occupying deep snow regions and explore whether a potential existed for increased interactions between coyotes and lynx due to snowmobile activity. We documented seasonal variation in coyote diets using scat collections to assess dietary overlap with lynx. Coyote resource use within and among habitats containing snowmobile activity was examined using coyote backtrack surveys during two consecutive field seasons in northwestern Wyoming. Although scat analysis findings suggest dietary overlap was not significant between coyotes and lynx during the winter or overall (all seasons combined), we lacked adequate sample size of lynx scats to determine if dietary overlap occurred during the fall, when coyote use of snowshoe hare peaked (24.1 % of all fall occurrences). Coyote backtrack surveys revealed that coyotes not only persisted in habitats used by lynx throughout the winter, but that snow compaction resulting from winter recreation use appeared to influence coyote movements during the winter months. Microhabitat analysis revealed that snow conditions influenced coyote behaviors and habitat use. This research provided insight into the impacts of winter recreation on coyote diet and habitat use during the winter months in northwestern Wyoming. In addition, these results have implications for local lynx populations in the southern periphery of their natural range. These results may assist land management agencies in planning and implementing management strategies to enhance lynx recovery, and may be used to guide decisions regarding areas designated for winter recreation and areas proposed for expansion of winter activities.
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Starr-Keddle, Ruth. "The influence of aspect, soil compaction and management on the grassland species composition of roadside verges, in relation to improving slope stability." Thesis, University of Newcastle Upon Tyne, 2011. http://hdl.handle.net/10443/1218.

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Roadside verge vegetation is a complex, unusual community, poorly understood and researched and a typical example of a “novel ecosystem”. The land has been altered by humans, the topsoil introduced from elsewhere, a seed mixture added and a management regime implemented. Vegetation is a cost effective, sustainable method for improving slope stability on steeper roadside slopes. On newly constructed roadside verges its rapid establishment prevents soil erosion and provides an aesthetic cover. The standard grass seed mixture sown includes grass species which are quick growing, vigorous and competitive. The belowground root system increases soil strength and the aboveground canopy reduces surface erosion, although soil compaction can restrict root and shoot growth. Morphological differences between grasses and wildflowers allow the root systems to utilise different soil strata and the aboveground canopy to fully exploit aboveground niches. Therefore maybe a species-rich grassland seed mixture should be sown to improve slope stability? The BIONICS Embankment at Nafferton Farm was used to investigate aspect and soil compaction on the establishment of a species-rich grassland. A second smaller Mesocosm experiment investigated the effects of aspect, soil compaction and cutting regimes on the aboveground composition and biomass, and the belowground rooting depths of two different seed mixtures. Also a survey of the plant communities and environmental characteristics of grass cuttings was carried out along the A303 and A38 in Wiltshire and Devon. On the BIONICS embankment 14 generalist plant species germinated from the seed mixture and arable and injurious weeds colonised. More wildflowers, e.g. Lotus corniculatus, grew on the south-facing slopes while more grasses and some herbs, e.g. Ranunculus repens, grew on the north-facing slopes. Ellenberg Indicator Values for fertility and moisture were higher on north-facing slopes, with light values greater on south-facing slopes. Lolium perenne, Medicago lupulina and Achillea millefolium were associated with the less compacted subsoil. In the Mesocosm experiment, L. perenne, Cynosurus cristatus, Phleum bertolonii, Daucus carota, Leucanthemum vulgare, Plantago lanceolata, Rumex acetosa and Sanguisorba minor were common. More wildflowers were found on the south-facing plots, such as L. vulgare and P. lanceolata, whereas the grasses L. perenne and C. cristatus preferred the north-facing plots. Frequent cutting increased species richness and diversity, favoured C. cristatus and L. 4 vulgare and reduced L. perenne and P. lanceolata. Grasses such as L. perenne and P. bertolonii were more reduced by compaction than the wildflowers such as Rhinanthus minor and Trifolium pratense. Plots sown with a mixture of grasses and wildflowers had greater above-ground biomass than the grasses-only plots and on the north-facing aspect had greater biomass than the flat and south-facing plots. Plots just sown with grasses had higher biomass on the flat plots. R. minor did not germinate well in the plots with high biomass but survived in regularly cut plots. Plant roots in the Mesocosms grew down the whole soil profile in all treatments (40 cm). The total root mass was greater in the grasses-only plots in comparison to the grass and wildflower plots. However, the grass roots were smaller and finer, whereas the wildflower roots were bigger, yet lighter. Although the grasses-only plots had greater root mass, these plots had lower aboveground biomass, while the grass and wildflower plots had lower root mass, but greater aboveground biomass. Bulk density (BD) and Penetrometer resistance (CI) was greater in the compacted treatment, although this did not reduce root mass, or reduce aboveground biomass. However, CI was greatest in the flat and south-facing plots where root mass was less, and CI was lower in the north-facing plots where root mass was greater. The roadside survey showed that natural colonisation could produce species-rich habitats over time with 116 species found. Arrhenatherum elatius was the commonest grass, Cirsium arvense and Senecio jacobaea were frequent and scrub encroachment was widespread. These roadside verges were not cut frequently enough to prevent succession into scrub and woodland. Centaurea nigra, L. vulgare and D. carota had higher cover on south-facing slopes, contributing to the higher diversity on this aspect. Signs of bareground and desiccation were greater on south-facing slopes. Grasses were more abundant on the north-facing slopes leading to mesotrophic communities on this aspect. Many sites had a unique and unusual combination of species that didn’t fit into the National Vegetation Classification (NVC). Roadside embankment construction does not hinder the establishment of a species-rich seed mixture, although a regular cutting regime is required of at least once a year to prevent scrub encroachment and to reduce the spread of injurious weeds. A grass and wildflower seed mixture containing a range of functional types will have greater aboveground biomass, with a denser canopy and heterogeneous root system, which will help to prevent surface erosion and runoff and increase soil strength.
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Books on the topic "Relative compaction"

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Lasemi, Zakaria. Porosity reduction in microcrystalline limestones: Recognizing the relative effects of cementation and compaction. 1990.

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2

White, Robert E. Understanding Vineyard Soils. Oxford University Press, 2015. http://dx.doi.org/10.1093/oso/9780199342068.001.0001.

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The first edition of Understanding Vineyard Soils has been praised for its comprehensive coverage of soil topics relevant to viticulture. However, the industry is dynamic--new developments are occurring, especially with respect to measuring soil variability, managing soil water, possible effects of climate change, rootstock breeding and selection, monitoring sustainability, and improving grape quality and the "typicity" of wines. All this is embodied in an increased focus on the terroir or "sense of place" of vineyard sites, with greater emphasis being placed on wine quality relative to quantity in an increasingly competitive world market. The promotion of organic and biodynamic practices has raised a general awareness of "soil health", which is often associated with a soil's biology, but which to be properly assessed must be focused on a soil's physical, chemical, and biological properties. This edition of White's influential book presents the latest updates on these and other developments in soil management in vineyards. With a minimum of scientific jargon, Understanding Vineyard Soils explains the interaction between soils on a variety of parent materials around the world and grapevine growth and wine typicity. The essential chemical and physical processes involving nutrients, water, oxygen and carbon dioxide, moderated by the activities of soil organisms, are discussed. Methods are proposed for alleviating adverse conditions such as soil acidity, sodicity, compaction, poor drainage, and salinity. The pros and cons of organic viticulture are debated, as are the possible effects of climate change. The author explains how sustainable wine production requires winegrowers to take care of the soil and minimize their impact on the environment. This book is a practical guide for winegrowers and the lay reader who is seeking general information about soils, but who may also wish to pursue in more depth the influence of different soil types on vine performance and wine character.
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Book chapters on the topic "Relative compaction"

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Singh Thakur, Adarsh, Naman Kantesaria, and Ajanta Sachan. "Effect of Relative Compaction on Dynamic Behaviour of Low Plasticity Cohesive Soil." In Lecture Notes in Civil Engineering, 109–19. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-33-4001-5_11.

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"relative compaction." In Dictionary Geotechnical Engineering/Wörterbuch GeoTechnik, 1100. Berlin, Heidelberg: Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-642-41714-6_181383.

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Naveed, Muhammad. "Advances in measuring mechanical properties of soil in relation to soil health." In Advances in measuring soil health, 215–40. Burleigh Dodds Science Publishing, 2021. http://dx.doi.org/10.19103/as.2020.0079.15.

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Although mechanical properties of soil are fast and easy to measure, they have not been used as indicators of soil health apart from cone penetration resistance. The confined compression test is traditionally used for the prediction of soil compaction risks. Other mechanical tests such as soil rheometry, miniature indentation test, and tensile strength are used for assessing the impact of certain amendments on the stability of the soil. Rheological techniques are appropriate to investigate microstructural stability of soil on a particle-particle scale. Miniature indentation test is very useful to perform when mechanical properties of soil are required to measure at the mm scale. Measurement of the tensile strength of soil has an advantage as it eliminates the effect of water content. There is clearly a need for more practical and rigorous testing on comparing different mechanical properties of the soil to test how they perform relative to each other.
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Furbish, David Jon. "Introduction." In Fluid Physics in Geology. Oxford University Press, 1997. http://dx.doi.org/10.1093/oso/9780195077018.003.0005.

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Fluids are involved in virtually all geological processes. Obvious examples are phenomena occurring at Earth’s surface in which fluid flow is a highlight: the flow of a lava stream, the play of a geyser, river flow and wind currents, the swash and backswash on a beach. Also obvious are phenomena that occur in the presence of fluid flows, such as sediment motion. Less obvious, but readily imaginable in terms of their behaviors, are fluid motions occurring within Earth’s crust: flows of magma and ground water, and expulsion of brines from sediments during compaction. In addition, a bit of reflection will recall a host of phenomena in which fluid behavior, although not the highlight, may nonetheless take on a significant role: initiation of landslides, seismic activity, glacier movement, taphonomic organization, and fracture mechanics. With these should be considered instances in which the geological material containing a fluid can influence its fundamental behavior at a molecular scale. An example is flow through very small rock pores, where molecular forces interacting among fluid molecules and pore surfaces can lead to a structural arrangement of the fluid molecules such that their mechanical behavior is unlike that which occurs in large pores, where the bulk of the fluid is “far” from pore surfaces. It is thus understandable that to describe many geologic phenomena requires knowing how fluids work. It is also natural to begin by considering how fluids behave in a general way, then in turn, how they are involved in specific geological processes. There are several approaches for describing fluids and their motions, and the choice of one, or some combination, depends on the sort of insight desired as well as the specific problem being considered. Fluid statics, as the name implies, involves considering the properties of fluids that are at rest in some inertial frame of reference. Note that this frame of reference may actually be moving relative to the Earth frame of reference, so long as the fluid motion is like that of a rigid body. An important example of our use of fluid statics will be in developing the hydrostatic equation, which formalizes how fluid pressure varies with depth.
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Glyn Bengough, A., Donald Campbell, and Michael O‚ÄôSullivan. "Penetrometer Techniques in Relation to Soil Compaction and Root Growth." In Soil and Environmental Analysis. CRC Press, 2000. http://dx.doi.org/10.1201/9780203908600.ch10.

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Guttmann, Oliver P., and Perry Elliott. "The cardiomyopathies: Hypertrophic, dilated, restrictive, and right ventricular." In Oxford Textbook of Medicine, edited by Jeremy Dwight, 3468–89. Oxford University Press, 2020. http://dx.doi.org/10.1093/med/9780198746690.003.0354.

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The term cardiomyopathy is used to describe heart muscle disease unexplained by abnormal loading conditions (hypertension, valve disease, and others), congenital cardiac abnormalities, and ischaemic heart disease. The current classification is based on the predominant phenotype, that is, hypertrophic, dilated, arrhythmogenic right ventricular, restrictive, and unclassifiable (including left ventricular non-compaction), and— where possible— incorporating inheritance and genotype. The diagnosis of hypertrophic cardiomyopathy is based on the demonstration of unexplained myocardial hypertrophy, defined as a wall thickness measurement exceeding two standard deviations above normal for gender and age. In practice, in an adult of normal size, the presence of a left ventricular myocardial segment of 1.5 cm or greater in thickness is diagnostic. Less stringent criteria should be applied to first-degree relatives of an unequivocally affected individual.
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Mogensen, Jens, and Torsten B. Rasmussen. "Left ventricular non-compaction: diagnosis and clinical management." In ESC CardioMed, 1509–12. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780198784906.003.0364.

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Left ventricular non-compaction (LVNC) is characterized by a specific morphological appearance of the myocardium with an inner non-compacted hypertrabeculated layer and deep recesses communicating with the left ventricular cavity, and an outer compacted myocardium. LVNC is a specific morphological finding and may be present in healthy individuals with apparently normal hearts and in patients with various cardiac and systemic conditions including X-linked Barth syndrome, cardiomyopathies, congenital heart diseases, and non-cardiac systemic diseases. Recent investigations have revealed that LVNC may appear as the sole manifestation of disease in carriers of genetic mutations associated with dilated and hypertrophic cardiomyopathies. Therefore, it is important to consider the possibility of familial disease when diagnosing LVNC and explore the family history of the patient. Clinical screening of relatives should be offered when familial disease is suspected or when LVNC remains unexplained. Anticoagulation should be considered when LVNC appears in patients with impaired systolic function of the left ventricle to avoid formation of thrombi and cardiac embolization following an assessment of the entire risk profile of the individual patient.
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Mogensen, Jens, and Torsten B. Rasmussen. "Left ventricular non-compaction: diagnosis and clinical management." In ESC CardioMed, 1509–12. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780198784906.003.0364_update_001.

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Left ventricular non-compaction (LVNC) is characterized by a specific morphological appearance of the myocardium with an inner non-compacted hypertrabeculated layer and deep recesses communicating with the left ventricular cavity, and an outer compacted myocardium. LVNC is a specific morphological finding and may be present in healthy individuals with apparently normal hearts and in patients with various cardiac and systemic conditions including X-linked Barth syndrome, cardiomyopathies, congenital heart diseases, and non-cardiac systemic diseases. Recent investigations have revealed that LVNC may appear as the sole manifestation of disease in carriers of genetic mutations associated with dilated and hypertrophic cardiomyopathies. Therefore, it is important to consider the possibility of familial disease when diagnosing LVNC and explore the family history of the patient. Clinical screening of relatives should be offered when familial disease is suspected or when LVNC remains unexplained. Anticoagulation should be considered when LVNC appears in patients with impaired systolic function of the left ventricle to avoid formation of thrombi and cardiac embolization following an assessment of the entire risk profile of the individual patient.
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Osipov, Vladimir, Vyacheslav Platonov, Vladislav Shitov, and Vladimir Solomonov. "From the Laser Plume to the Laser Ceramics." In Ceramic Materials [Working Title]. IntechOpen, 2020. http://dx.doi.org/10.5772/intechopen.94464.

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The main stages of preparation of ceramic active elements of solid-state lasers are considered. The physical principles of laser synthesis of nanopowders are described. The features and processes taking place during compaction and compacts sintering are specified. Also we report on the investigation of characteristics of highly transparent ceramics on the basis of nanopowders synthesized in laser plume. It is shown that this approach enables to increase the “orange peel” formation threshold in the ceramics with strongly disordered crystalline structure. It opens the road to relatively simple synthesis technology from oxide materials and application of this ceramics as the gain media with oscillation efficiency higher than 50% and also leads to simplification of the synthesis technology of magnetoactive ceramics and to production of highly transparent YAG samples without the use of sintering heterovalent additives.
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CAMPBELL, D. J. "Determination and Use of Soil Bulk Density in Relation to Soil Compaction." In Developments in Agricultural Engineering, 113–39. Elsevier, 1994. http://dx.doi.org/10.1016/b978-0-444-88286-8.50014-3.

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Conference papers on the topic "Relative compaction"

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Boone, Michael, and Donald Gerken. "Moisture Content and Relative Compaction Influences on Swell Potential and Strength of a Compacted Residual Soil." In IFCEE 2015. Reston, VA: American Society of Civil Engineers, 2015. http://dx.doi.org/10.1061/9780784479087.054.

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Kishore, Vipuil, Mousa Younesi, Stefi Panit, and Ozan Akkus. "Electrochemical Compaction of the Collagen: Effects on Matrix Mechanics and MSC Response." In ASME 2013 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/sbc2013-14361.

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The molecules of the extracellular matrix in connective tissues are densely packed. Biofabrication methods to attain such molecular packing density are limited and electrochemical processing (EP) of monomeric collagen solutions is one of few means to attain molecular packing. During EP, the pH gradient between electrodes drives the electrophoretic mobility of collagen molecules toward the isoelectric point where molecules are compacted. Our earlier work used linear electrodes to fabricate highly aligned crosslinked collagen fibers for tendon tissue engineering [1–4]. Prior work compared electrocompacted-aligned matrices with uncompacted randomly oriented ones. Therefore, the effects of alignment and compaction were compounded in terms of assessing cell response. So as to take the matrix alignment variable out of the picture to investigate matrix compaction effects only, we employed disc shaped electrodes to obtain electrocompacted sheets which lack matrix alignment. The current study investigated: a) the degree of compaction, b) effect of compaction on the mechanical properties of the sheets, and, c) mesenchymal stem cell (MSC) proliferation and morphology on compacted sheets relative to uncompacted collagen gels.
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Pooranampillai, Suthan, Sherif Elfass, Walt Vanderpool, and Gary Norris. "The Effects of Compaction Post Grouting of Model Shaft Tips in Fine Sand at Differing Relative Densities—Experimental Results." In Art of Foundation Engineering Practice Congress 2010. Reston, VA: American Society of Civil Engineers, 2010. http://dx.doi.org/10.1061/41093(372)24.

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King, Graeme. "Physical Forces on Buried Pipeline Coatings." In 2000 3rd International Pipeline Conference. American Society of Mechanical Engineers, 2000. http://dx.doi.org/10.1115/ipc2000-182.

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Physical forces activated when buried pipelines move relative to the soil can damage coatings. The problem is most common near bends and areas with poor backfill compaction. Most solutions are best implemented early in the design work when pipeline routes, alignments, and operating conditions are being selected. Solutions, in addition to the obvious one of increasing toughness and adhesion of coatings, include increasing radius of bends, avoiding unstable slopes, improving backfill operations, stabilizing operating conditions, and reducing operating pressures and temperatures.
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Shanjani, Yaser, Ehsan Toyserkani, and Christina Wei. "Modeling and Characterization of Biomaterials Spreading Properties in Powder-Based Rapid Prototyping Techniques." In ASME 2007 International Mechanical Engineering Congress and Exposition. ASMEDC, 2007. http://dx.doi.org/10.1115/imece2007-42530.

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In this work, the spreading properties of biomaterials, while a counter-rotating roller is used in rapid prototyping machines, are modeled and characterized. For modeling, the slab method is used in which biomaterial geometrical properties are incorporated into the model. A pressure dependent plasticity model is used as a constitutive model for biomaterial powders. In addition, the coulomb friction law for the powder-roller interface boundary is incorporated into the model. Size and shape of powder particles as well as roller rotational and linear velocities are considered within the friction coefficient. Powder bed parameters such as compaction pressure, stress distribution and relative density are predicted using the simulation.
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Maines, Warren R., Lalit Chhabildas, William D. Reinhart, and Tom F. Thornhill. "High Velocity Uniaxial Strain Response of ERG Aerospace Aluminum Foam." In ASME 2010 Pressure Vessels and Piping Division/K-PVP Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/pvp2010-25060.

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We report the results of uniaxial strain experiments of ERG Aerospace aluminum foam, at 50% relative density up to 10 GPa. The reverse ballistic plate reverberation technique was used to obtain shock compression states of the material. In these tests, 6061 T-6 aluminum, oxygen free homogenous copper (OFHC), and tantalum were used as standard material targets and were shocked by an aluminum foam projectile traversing up to 2.0 km/s. The response of the target plates were monitored by three different velocity interferometers positioned at three different locations on the witness plate. This provided us with the compaction behavior of the foam material in three discrete locations per sample, due to the presence of porosity in the foam material.
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Israr, Jahanzaib, Buddhima Indraratna, and Cholachat Rujikiatkamjorn. "Experimental Investigation into Internal Erosion Potential for Granular Filters." In The 13th Baltic Sea Region Geotechnical Conference. Vilnius Gediminas Technical University, 2016. http://dx.doi.org/10.3846/13bsgc.2016.037.

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Internal erosion is a phenomenon whereby the filtrates under the influence of significant seepage forces accompany the finer fraction from potential internally unstable filters (e.g. broadly- and gap-graded soil), occasionally rendering them ineffective. The filter assessment for internal erosion or instability potential is emphasized through particle size distribution based geometrical criteria ignoring the effect of compaction. In this study, the results of hydraulic gradient controlled internal erosion tests conducted over a wide range of compacted sand-gravel mixtures were used to analyse some of the available geometrical criteria, which interestingly showed partial success in assessing the filter’s internal erosion potential. It was revealed that the occurrence of internal erosion is a combined function of particle size distribution and the relative density of soils that had been ignored in many of the existing criteria. A comparison between the assessments obtained from some of the particle size based criteria and that from a constriction size based technique was reported for a large body of published data. It was observed that the latter criterion, which incorporates the effects of both particle size distribution and relative density of soils in tandem, could assess the reported test results with higher accuracy.
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Asawapishayachote, T., J. Carmai, and A. Manonukul. "Numerical Analysis of Powder Forging Under Various Initial Density Distributions and Friction Conditions." In ASME 2005 International Mechanical Engineering Congress and Exposition. ASMEDC, 2005. http://dx.doi.org/10.1115/imece2005-80704.

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Finite element models have been developed to simulate forging of sintered porous powder metal. The deformation behaviour of the porous preform during hot forging has been described by the Duva and Crow porous material constitutive model. It has been implemented into general purpose nonlinear finite element software within a large deformation formulation. Most of the previous finite element analyses of the deformation of this porous preform always assume an initial homogeneous density distribution within the compacted porous preform. However, the compacted parts obtained after compaction and sintering usually possess inhomogeneous density distribution. The present finite element models therefore take into account the initial distribution of relative density within the preform. The simulations have been conducted for various initial density distributions and under various frictional conditions in order to investigate the deformation characteristics and the evolution of voids in the forging process.
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Heshmat, Hooshang. "Experimental Determination of Powder Film Shear and Damping Characteristics." In ASME Turbo Expo 2000: Power for Land, Sea, and Air. American Society of Mechanical Engineers, 2000. http://dx.doi.org/10.1115/2000-gt-0368.

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Thin powder films are proposed as a damping medium to overcome the temperature and creep limitations associated with viscoelastic dampers. Its basis is the established quasi-continuum model for fine powders successfully applied to such devices as bearings, piston rings, conventional dampers and others. In developing this technology over the past ten years it has been shown that satisfactory performance with respect to levels of load capacity, friction, etc. can be achieved with powder films which operate in a quasi-viscous mode much as fluid films do. Direct measurements have demonstrated that high levels of damping are possible at high frequencies even with extremely small excitational amplitudes, and that the achieved stiffness and damping are insensitive to temperature. Apart from its physical characteristics, measured stiffness and damping of powder films were shown to be related to powder compaction pressure, relative velocity, film thickness and imposed shear stress. With its Theological characteristics established thin powder layers should then be applicable as dampers in such devices as turbine airfoils, struts, guide vanes, exhaust ducts and similar systems subject to high frequency vibrations and high temperatures.
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Saunders, Amanda M., and Darris White. "Estimating Traction Forces for Pneumatic Tires on Soft Soils With Application to BAJA SAE Vehicles." In ASME 2019 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/imece2019-10770.

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Abstract BAJA SAE is an engineering competition that tasks team with designing single-seat all-terrain vehicles that partake in a variety of events, predominantly on soft soils. Events range from (off-road) land maneuverability, hill climb, tractor pull, and timed acceleration. Tire-terrain interaction strongly influences the performance of off-road vehicles. Tire terrain traction is limited by the mechanical properties for soft soils; therefore, understanding tire-terrain traction forces is important for assessing vehicle performance. Using the stress integration method (SIM) initiated by Bekker and developed by Wong, this paper analyzes the performance of BAJA SAE tires using Bekker’s defined terrain measurements for soft soils. The relative rigidity of the tire versus the soil, in terms of pressure, was compared for operating conditions and used to determine the tire state (rigid wheel or pneumatic tire). Tire state determines shape of the tire-terrain interface, and integration limits. Based on the operating conditions, the tire sinkage into the soil was calculated and used to determine compaction resistance, tire hysteresis, and normal pressures along the tire-terrain interface. Using the SIM, the longitudinal and lateral tractive forces vs the slip ratio and slip angle, respectively, were calculated for a range of operation conditions. The tire-terrain traction forces were evaluated for different tire diameters and tire pressure for a range of soil types. The described process can be used to predict performance for BAJA SAE teams participating in specific events and the results can be used as a basis for selecting tires and tire pressure for dynamic events.
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