Installation and Field Testing of High Performance Repair Materials for Pavements and Bridge Decks

Pavement patching is a common maintenance activity in the state of Ohio, due to numerous freeze-thaw cycles. The Ohio Transportation (ODOT) has a need for durable, more permanent high performing pavement and bridge deck materials that allow for a faster repair and for user safety. New or proprietary products were chosen, installed, and monitored in order to specify for use in future ODOT construction, based on the field performance of the products. The objective of this study was to document the investigation, installation, and field testing of the previously chosen high performance patching materials. The investigation determined the proper field testing criteria used throughout this project. The installation of the patches was performed in both winter and summer weather conditions. Observations regarding the different products installed, and the installation process, were documented throughout the installations in order to determine which products are easier to install, and in order to document the potential problems that could arise throughout a future patching project. Field testing and visual inspections were performed throughout the project as well, in order to determine the overall performance of the products being tested. The proper installation and testing of these new products will assist in determining the overall performance of these patching product

Installation and Field Testing of High Performance Repair Materials for Pavements and Bridge Decks

Pavement patching is a common maintenance activity in the state of Ohio, due to numerous freeze-thaw cycles. The Ohio Transportation (ODOT) has a need for durable, more permanent high performing pavement and bridge deck materials that allow for a faster repair and for user safety. New or proprietary products were chosen, installed, and monitored in order to specify for use in future ODOT construction, based on the field performance of the products. The objective of this study was to document the investigation, installation, and field testing of the previously chosen high performance patching materials. The investigation determined the proper field testing criteria used throughout this project. The installation of the patches was performed in both winter and summer weather conditions. Observations regarding the different products installed, and the installation process, were documented throughout the installations in order to determine which products are easier to install, and in order to document the potential problems that could arise throughout a future patching project. Field testing and visual inspections were performed throughout the project as well, in order to determine the overall performance of the products being tested. The proper installation and testing of these new products will assist in determining the overall performance of these patching product

Assessment of the possibility of applying selected pedotransfer functions for indicating the retention of forest soils in Poland

Landscape retention influences the water balance of a catchment and the course of flooding events. The degree of retention capabilities of forest soils are much less known than the retention of land used for agriculture. Soil retention capacity influences the formation of a given forest habitat type, floristic species composition, as well as the type and quality of the stand of trees. The analysis was carried out for a regression model dedicated to selected forest soils within the area of Poland, as well as van Genuchten’s and Wösten’s, and Varallyay’s and Mironienko’s models. In order to assess the fit of the models, an independent series of forest soils were used. The models prepared for soils used for agricultural purposes do not result in statistically acceptable fit when it comes to the analyzed forest soils. The analysis of measured and calculated values of total available water indicate good fit of the regression model developed for the analyzed group of podzolic and brown forest soils

Analysis of Syngas Production from Catalytic Biogas Reforming and Upgrading

The development of alternative and sustainable technologies for the production of liquid biofuels has gained ground worldwide. Biogas is one of the most potential feedstocks to be used and the Fischer-Tropsch (FT) route is one of the most studied processes for the production of these liquid biofuels. In this work, different processes for the conversion of biogas to syngas by catalytic reforming were studied, in order to evaluate the better route to obtain the syngas and its usage as feedstock in FT synthesis. Two steps were analyzed using Aspen Plus V12.1®: 1) biogas upgrading; and 2) catalytic reforming process. Dry reforming (DR) and Bi reforming (BR) were selected for the reforming process assessment. CH4 and CO2 conversions were selected to evaluate the process performance. Results showed that water scrubbing is a better route to perform biogas upgrading, based on the H2S final content and the CH4 recovery. Besides, for the biogas reforming process, all scenarios presented an increase in conversions when the temperature was increased. For bi reforming, which uses biogas and water steam as reactants, a decrease in the molar fraction of H2O contributed to higher CO2 conversion. The BR process with a molar ratio of CH4, CO2, and H2O at 3:2:1, respectively, at elevated temperatures and pressure of 0.1 MPa, showed the most promising combination of results for syngas production, considering environmental and operational factors. The CH4 and CO2 conversions obtained in 900 °C were 96.45% and 98.06%, respectively

Assessment of CO2 Conversion in a Biorefinery Concept: a Biomethane Plant Case Study

One of the main challenges imposed by the climate crisis is to reduce the greenhouse gases emissions while keeping high levels of social and economic development. Therefore, the deployment of process alternatives that use residues as raw materials and integrate the conversion of by-products in added value products of interest is mandatory and integrated biorefineries play a major role in this context. In this work, thermodynamic analyses were performed to assess the conversion of a residual CO2 stream captured from the flue gases of a biomethane-based thermal power plant into syngas or methane. Results showed that the syngas production from CO2 is favored at high temperatures (>700 °C), low pressures (1 bar) and low H2/CO2 ratios (e.g. 1). Conversely, methane formation is favored at lower temperatures and higher H2/CO2 ratios. Simulations were also carried out considering the conversion of an off-gas stream from a biomethane plant, with different concentrations of CH4. Considering the syngas formation, the presence of CH4 in the feed stream enhances the CO2 conversion and increases the production of CO and H2 (desired products), while decreasing H2O formation (unwanted side product), possibly due to the simultaneous occurrence of the methane bi-reforming, RWGS and methanation reactions. Therefore, from the thermodynamic point of view, the use of the off-gas from a biomethane plant for syngas production could be a potential alternative for the destination of this residual stream, converting it into interesting chemical platforms and intermediates for fuels and chemicals production

Dynamics of canopy development of Cunninghamia lanceolata mid-age plantation in relation to foliar nitrogen and soil quality influenced by stand density

It has been generally accepted that different silvicultural practices affect the forest canopy morphology and structure. During forest establishment, many natural sites were converted to coniferous plantations in southern China. Retention of the canopy during stand conversion may be desirable to promote ecological function and meet conservation objectives. We tested the impact of planting density, foliar nitrogen and soil chemical properties on the canopy development of Chinese fir (Cunninghamia lanceolata) mid-age monoculture stands. Low density (1450 trees hm−2 with planting spacing of 2.36 × 2.36 m), intermediate-density (2460 trees hm−2 with planting spacing of 1.83 × 1.83 m) and high density (3950 trees hm−2 with planting spacing of 1.44 × 1.44 m) stands were selected in Xinkou forest plantations in Sanming City, China. Canopy characteristics such as leaf area index (LAI), mean tilt angle of the leaf (MTA) and average canopy openness index (DIFN) were measured. Measurements were taken using LAI-2200 PCA. The results illustrated that stand density was the primal factor responsible in canopy structuring while soil chemical properties seem to play a secondary role for canopy dynamics. LAI increased from 3.974 m2 m-2 to 5.072 m2 m-2 and MTA increases from 34.8° to 48.7° as the stand density increased while the DIFN decreased from 0.1542 to 0.0902 with the increasing stand density but it was no significantly different in intermediate and high-density stands. Additionally, LAI and MTA were positively correlated to foliar nitrogen while the DIFN was negatively correlated. In general, soil available nitrogen, available phosphorus and soil pH were not significant to canopy parameters. The results presented provide guiding principles about the canopy dynamics distribution in varying stand densities from LICOR measurements in mid-age Chinese fir monoculture. Furthermore, this provides a base to study canopy dynamics at mature stage forests because of more senescence activities.This research was financially supported by the National Natural Science Foundation of China (31870614 and 30970451), the Forestry Peak Discipline Project of Fujian Agriculture and Forestry University, China (71201800716) and Postdoctoral research funding of Central South University of Forestry and Technology (70702-45200003)