Characterization and CPDM modeling of volatile fatty acid fermentation with cotton gin trash and chicken manrure as substrates

Due to the character of the original source materials and the nature of batch digitization, quality control issues may be present in this document. Please report any quality issues you encounter to [email protected], referencing the URI of the item.Includes bibliographical references: leaf 29.With literally tons of biomass produced annually, a process that uses this waste as a feedstock would help reduce the problem of disposal. The MixAlco process is one that does just that. It converts biomass through anaerobic fermentation into volatile fatty acids, mixed alcohols, and ketones. These products can be used as raw chemicals or as fuel for their heating value. The process must be implemented on an industrial scale in order to obtain significant amounts of the products. The substrates evaluated in this study are municipal solid waste (MSW), sewage sludge (SS), cotton gin trash (GT), and chicken manure (CM). The product concentrations obtained from using MSW and SS as the substrate were low compared to those obtained with GT and CM. Maximum product concentrations when using GT and CM at a temperature of 55₉C were 22 g of total acid/L with acetic acid constituting 78 % of the total acids. The Continuum Particle Distribution Modeling (CPDM) method is also applied to data collected for batch reactions. The model can accurately predict acid concentrations when excessive decomposition of the acid is not occurring. However, when liquid residence times are extended and the products decompose, the model does not accurately predict the decreasing product concentrations

Investigation of the Scanning Microarc Oxidation Process

Scanning microarc oxidation (SMAO) is a coating process which is based on conventional microarc oxidation (MAO). The key difference is that deposition in SMAO is achieved by using a stainless steel nozzle to spray an electrolyte stream on the substrate surface as opposed to immersing the workpiece in an electrolyzer. In the present study, SMAO discharge characteristics, coating morphology, and properties are analyzed and compared to results obtained from MAO under similar conditions. Results show that MAO and SMAO have comparable spark and microarc lifetimes and sizes, though significant differences in incubation time and discharge distribution were evident. Results also showed that the voltage and current density for MAO and SMAO demonstrate similar behavior but have markedly different transient and steady-state values. Results obtained from coating A356 aluminum sheet show that oxide thickness and growth rate in SMAO are strongly dependent on interelectrode spacing and travel speed. Analysis of the SMAO coating morphology and structure showed that a denser and slightly harder layer was deposited in comparison to MAO and is attributed to reduced porosity and increased formation of α-Al2O3. Preliminary results indicate that SMAO represents a viable process for coating of aluminum surfaces

Band engineering of a magnetic thin film rare earth monopnictide

Realizing quantum materials in few atomic layer morphologies is a key to both observing and controlling a wide variety of exotic quantum phenomena. This includes topological electronic materials, where the tunability and dimensionality of few layer materials have enabled the detection of $Z_2$, Chern, and Majorana phases. Here, we report the development of a platform for thin film correlated, topological states in the magnetic rare-earth monopnictide ($RX$) system GdBi synthesized by molecular beam epitaxy. This material is known from bulk single crystal studies to be semimetallic antiferromagnets with Neel temperature $T_N =$ 28 K and is the magnetic analog of the non-$f$-electron containing system LaBi proposed to have topological surface states. Our transport and magnetization studies of thin films grown epitaxially on BaF$_2$ reveal that semimetallicity is lifted below approximately 8 crystallographic unit cells while magnetic order is maintained down to our minimum thickness of 5 crystallographic unit cells. First-principles calculations show that the non-trivial topology is preserved down to the monolayer limit, where quantum confinement and the lattice symmetry give rise to a $C=2$ Chern insulator phase. We further demonstrate the stabilization of these films against atmospheric degradation using a combination of air-free buffer and capping procedures. These results together identify thin film $RX$ materials as potential platforms for engineering topological electronic bands in correlated magnetic materials

Direct Measure of Giant Magnetocaloric Entropy Contributions in Ni-Mn-In

Off-stoichiometric alloys based on Ni 2 MnIn have drawn attention due to the coupled first order magnetic and structural transformations, and the large magnetocaloric entropy associated with the transformations. Here we describe calorimetric and magnetic studies of four compositions. The results provide a direct measure of entropy changes contributions including at the first-order phase transitions, and thereby a determination of the maximum field-induced entropy change corresponding to the giant magnetocaloric effect. We find a large excess entropy change, attributed to magneto-elastic coupling, but only in compositions with no ferromagnetic order in the high-temperature austenite phase. Furthermore, a molecular field model corresponding to antiferromagnetism of the low-temperature phases is in good agreement, and nearly independent of composition, despite significant differences in overall magnetic response of these materials

MANDATORY VERSUS VOLUNTARY PRICE REPORTING: AN EMPIRICAL INVESTIGATION OF THE MARKET TRANSPARENCY CONTROVERSY

The ability of the former voluntary price reporting system to generate market transparency in U.S. livestock markets was called into question by producer groups and academic research prior to the new federal system of mandatory price reporting being implemented. The market transparency issue is investigated by comparing price data collected from the former AMS voluntary price reporting system to mandatory price reporting data for live slaughter steers collected by the State of South Dakota before the advent of the new federal system. The relationship between a set of public price report series and the South Dakota mandatory price series is analyzed using cointegration techniques. The empirical findings indicate a strong long-run and short-run integrated relationship between the mandatory price series and a majority of the selected public price reports. We conclude that in the cash market for live steers in South Dakota, the former voluntary price reporting system did foster market transparency and aided in the price discovery process.Marketing,

Calorimetric and magnetic study for Ni50_{50}Mn36_{36}In14_{14} and relative cooling power in paramagnetic inverse magnetocaloric systems

The non-stoichiometric Heusler alloy Ni$_{50}$Mn$_{36}$In$_{14}$ undergoes a martensitic phase transformation in the vicinity of 345 K, with the high temperature austenite phase exhibiting paramagnetic rather than ferromagnetic behavior, as shown in similar alloys with lower-temperature transformations. Suitably prepared samples are shown to exhibit a sharp transformation, a relatively small thermal hysteresis, and a large field-induced entropy change. We analyzed the magnetocaloric behavior both through magnetization and direct field-dependent calorimetry measurements. For measurements passing through the first-order transformation, an improved method for heat-pulse relaxation calorimetry was designed. The results provide a firm basis for the analytic evaluation of field-induced entropy changes in related materials. An analysis of the relative cooling power (RCP), based on the integrated field-induced entropy change and magnetizing behavior of the Mn spin system with ferromagnetic correlations, shows that a significant RCP may be obtained in these materials by tuning the magnetic and structural transformation temperatures through minor compositional changes or local order changes