ALTERNATIVE METHODS OF ACCOUNTING FOR LIVESTOCK CAPITAL FORMATION: AN APPLICATION TO SOUTHERN U.S. AGRICULTURE

Livestock Production/Industries,

Aurora Volume 23

College formerly located at Olivet, Illinois and known as Olivet University, 1912-1923; Olivet College, 1923-1939, Olivet Nazarene College, 1940-1986, Olivet Nazarene University, 1986-https://digitalcommons.olivet.edu/arch_yrbks/1089/thumbnail.jp

Assessing the toxicity of a reconstituted water simulating streams influenced by mountaintop mining in central Appalachia

Freshwater ecosystems in Central Appalachia experience increased concentrations of manganese (Mn) and total dissolved solids from the runoff of surface mines and valley fills. Biological communities have been impacted by these surface mining operations and it has been suggested that the increase in total dissolved solids may contribute to these negative effects, but standard laboratory toxicity tests have not found increased concentrations of total dissolved solids to have such negative effects as seen in the field. The elevated total dissolved solids in mining influenced streams may only be toxic in conjunction with another toxicant that is presence in these systems such as manganese. This study’s primary goal was to determine the toxic effects of a simulated mine water representative of elevated ionic conditions in mining influenced streams of Central Appalachia on the fathead minnow (Pimephales promelas) and examine potential cumulative effects with manganese. Breeding colonies were exposed to different concentrations of the simulated mine water then toxicity tests were performed with manganese on the embryos and larvae. The adverse effects of the combination of toxicants were determined using traditional and non-traditional toxicity testing endpoints. This study found that fathead minnow larval growth was decreased in a concentration of 10 mg Mn/L in conjunction with a 50% dilution of the simulated mine water, but no effect was observed at higher simulated mine water concentrations most likely because of the increased water hardness that is known to reduce both sulfate and manganese toxicity. The concentration of sulfate in the simulated mine water was more toxic when combined with manganese in comparison to historic data for sulfate toxicity. These findings could be applied to mitigation and restoration efforts for streams affected by mountaintop mining operations in Central Appalachia

Aurora Volume 23

College formerly located at Olivet, Illinois and known as Olivet University, 1912-1923; Olivet College, 1923-1939, Olivet Nazarene College, 1940-1986, Olivet Nazarene University, 1986-https://digitalcommons.olivet.edu/arch_yrbks/1089/thumbnail.jp

Crack Surveys of Low-Cracking High-Performance Concrete Bridge Decks in Kansas 2006-2008

The purpose and specifications for the construction of Low-Cracking, High-Performance Concrete (LC-HPC) bridge decks are discussed. The survey process for evaluating the cracking performance of bridge decks is described. Seven LC-HPC decks and seven control decks were surveyed according to this process. Crack densities were calculated for each deck and trends in crack patterns were noted. The LC-HPC decks yielded significantly lower crack densities than did the control decks. Most cracks in LCHPC and control decks were oriented in the transverse direction and were located directly above the transverse reinforcement. For superelevated decks, crack densities were greater in areas of the deck at higher elevations, likely due to greater settlement cracking and inadequate curing on the elevated portion of the decks

Evaluation of Multiple Corrosion Protection Systems and Corrosion Inhibitors for Reinforced Concrete Bridge Decks

The corrosion performance of different corrosion protection systems is evaluated using the mortar-wrapped rapid macrocell test, bench-scale tests (the Southern Exposure, cracked beam, and ASTM G109 tests), and field tests. The systems include conventional steel with three different corrosion inhibitors (DCI-S, Hycrete, and Rheocrete), epoxy-coated reinforcement with three different corrosion inhibitors and ECR with a primer coating containing microencapsulated calcium nitrite, multiple-coated reinforcement with a zinc layer underlying an epoxy coating, ECR with zinc chromate pretreatment before application of the epoxy coating to improve adhesion between the epoxy and the underlying steel, ECR with improved adhesion epoxy coatings, and pickled 2205 duplex stainless steel. Conventional steel in concretes with two different water-cement ratios (0.45 and 0.35) is also tested. Of these systems, specimens containing conventional steel or conventional epoxy-coated steel serve as controls. The critical chloride thresholds of conventional steel in concrete with different corrosion inhibitors and zinc-coated reinforcement are determined. The results of the tests are used in an economic analysis of bridge decks containing different corrosion protection systems over a design life of 75 years. The results indicate that a reduced water-cement ratio improves the corrosion resistance of conventional steel in uncracked concrete compared to the same steel in concrete with a higher water-cement ratio. The use of a corrosion inhibitor improves the corrosion resistance of conventional steel in both cracked and uncracked concrete and delays the onset of corrosion in uncracked concrete, but provides only a very limited improvement in the corrosion resistance of epoxy-coated reinforcement due to the high corrosion resistance provided by the epoxy coating itself. Based on results in the field tests, the epoxy-coated bars with a primer containing microencapsulated calcium nitrite show no improvement in the corrosion resistance compared to conventional epoxy-coated reinforcement. Increased adhesion between the epoxy coating and reinforcing steel provides no improvement in the corrosion resistance of epoxy-coated reinforcement. The corrosion losses for multiple-coated reinforcement are comparable with those of conventional epoxy-coated reinforcement in the field tests in uncracked and cracked concrete. Corrosion potential measurements show that the zinc is corroded preferentially, providing protection for the underlying steel. Pickled 2205 stainless steel demonstrates excellent corrosion resistance, and no corrosion activity is observed for the pickled 2205 stainless steel in bridge decks, or in the SE, CB, or field test specimens after four years. ECR, ECR with increased adhesion, and pickled 2205 stainless steel are the most cost-effective corrosion protection systems based on the economic analyses of a 216-mm (8.5-in.) thick bridge deck over a 75-year design life

A Unification of LoS, Non-LoS and Quasi-LoS Signal Propagation in Wireless Channels

The modeling of wireless communications channels is often broken down into two distinct states, defined according to the optical viewpoints of the transmitter (TX) and receiver (RX) antennas, namely line-of-sight (LoS) and non-LoS (NLoS). Movement by the TX, RX, both and/or objects in the surrounding environment means that channel conditions may transition between LoS and NLoS leading to a third state of signal propagation, namely quasi-LoS (QLoS). Unfortunately, this state is largely ignored in the analysis of signal propagation in wireless channels. We therefore propose a new statistical framework that unifies signal propagation for LoS, NLoS, and QLoS channel conditions, leading to the creation of the Three State Model (TSM). The TSM has a strong physical motivation, whereby the signal propagation mechanisms underlying each state are considered to be similar to those responsible for Rician fading. However, in the TSM, the dominant signal component, if present, can be subject to shadowing. To support the use of the TSM, we develop novel formulations for the probability density functions of the in-phase and quadrature components of the complex received signal, the received signal envelope, and the received signal phase. Additionally, we derive an expression for the complex autocorrelation function of the TSM, which will be of particular importance in understanding and simulating its time correlation properties. Finally, we show that the TSM provides a good fit to field measurements obtained for two different bodycentric wireless channels operating at 2.45 GHz, which are known to be subject to the phenomena underlying the TSM.The State Research Agency (AEI) of SpainThe European Social Fund under grant RYC2020-030536-IAEI under grant PID2020-118139RB-I00

Use of Innovative Concrete Mixes for Improved Constructability and Sustainability of Bridge Decks 2010-2011

Bridge deck crack surveys were performed on twelve bridges on US-59 to determine the effects of mixture proportions, deck type, and girder types on the crack density of reinforced concrete bridge decks. Of the twelve, eight have prestressed concrete girders and four have steel girders. Four of the decks with prestressed girders have partial-depth precast deck panels, two are monolithic, and two have overlays. Of the four decks with steel girders, two have overlays and two are monolithic. The surveys were performed, crack maps were analyzed, and cracking trends were observed. The results for the US-59 bridge decks were compared with crack densities obtained in a study of low-cracking high-performance concrete (LC-HPC) bridge decks in Kansas. The monolithic concrete bridge decks supported by prestressed concrete girders within this study exhibit less cracking than decks supported by steel girders in the first three years. At an age of approximately three years, the US-59 monolithic decks on prestressed girders with deck panels are not displaying significant cracking at the joints of the panels. The US-59 decks supported by prestressed girders without overlays exhibit significantly less cracking than the decks on prestressed girders with overlays. No benefits of using fibers in either the overlay or in the deck have been observed in this study