Catalyst deterioration over the lifetime of small utility engines

In this paper, the deterioration of catalysts in small, four-stroke, spark-ignition engines is described. The laboratory testing performed followed a proven test method that mimics the lifetime of a small air-cooled utility engine operating under normal field conditions. The engines used were single-cylinder, 6.5-hp, side-valve engines. These engines have a nominal 125-hr lifetime. The effectiveness of the catalysts was determined by testing exhaust emissions before and after the catalyst to determine the catalyst's efficiency. This was done several times during the lifetime of the engines to determine the deterioration in the performance of the catalysts at lowering pollutant emissions. Additional testing was performed on the catalysts to determine wear patterns, contamination, and recoverable activity. The results indicate that considerable catalyst deterioration is occurring over the lifetime of the engine. The results reveal that soot buildup, poisons, and active surface loss appear to be the contributing factors to the deterioration. These results were determined after analyzing the exhaust emissions data, scanning electron microscope results analysis, and the impact of regeneration attempts. An ANOVA statistical analysis was performed, and it was determined that the emissions are also impacted, to some degree, by time and the engine itself.     

Fate of pharmaceuticals--photodegradation by simulated solar UV-light

The fate of pharmaceuticals in surface waters under solar irradiation was investigated. Photodegradation of pharmaceuticals caused by sun irradiation may be of major significance in the natural elimination process. Based on a data compilation from the literature, the lipid lowering agent metabolite clofibric acid, the iodinated X-ray contrast media iomeprol, which contribute to the adsorbable organic halogen compounds, and the antiepileptic drug carbamazepine were selected. The irradiation experiments were carried out in batch experiments with simulated UV–sunlight. The photodegradation of the pharmaceuticals showed a pseudo-first-order kinetics. The objective of this investigation was to demonstrate that the extent of photoinduced degradation of pharmaceuticals can vary significantly for the different pharmaceuticals and it strongly depends on the water constituents present in solution. The influences of different initial pharmaceutical concentrations, the presence of other pharmaceuticals like carbamazepine or clofibric acid and the presence of natural organic matter on the photochemical degradation rate of pharmaceuticals in aqueous solutions were investigated. Analyses of the pharmaceuticals and their photodegradation products were carried out by high performance liquid chromatography with diode-array and fluorescence detection.     

Solvent-Free Polymerization of l-Aspartic Acid in the Presence of d-Sorbitol to Obtain Water Soluble or Network Copolymers

l-Aspartic acid was thermally polymerized in the presence of d-sorbitol with the goal of synthesizing new, higher molecular weight water soluble and absorbent copolymers. No reaction occurred when aspartic acid alone was heated at 170 or 200 °C. In contrast, heating sorbitol and aspartic acid neat or with ammonium hydroxide gave a mixture of water soluble and insoluble copolymers of polysuccinimide and sorbitol. In the presence of phosphoric acid, sorbitol aspartate ester copolymers having both water soluble and highly swollen gel components were formed. These results indicate that polysaccharides such as sorbitol can readily react to form copolymer ester/amides with aspartic acid and such copolymers may have utility as biodegradable water soluble and swellable polyampholytes.     

Increased functionality of methyl oleate using alkene metathesis

A series of alkene cross-metathesis reactions were performed using a homogeneous ruthenium-based catalyst. Using this technology, a variety of functional groups can be incorporated into the bio-based starting material, methyl oleate. Trans-stilbene, styrene, methyl cinnamate and hexen-3-ol have all been shown to give desirable products. Using this technology, aromatics, alcohols or additional esters can be incorporated into the products. For example, the cross-metathesis reaction of methyl oleate with methyl cinnamate by the second-generation Grubbs catalyst showed 70% conversion of methyl oleate into products where half of the observed products contain an aromatic group and over one-third of the products contain an α,β-unsaturated methyl ester. This promising green route is versatile, and with an appropriate selection of starting materials, it is applicable to the synthesis of polymer precursors, industrial fluids or any other application where the upgrade of natural oils is necessary.     

Predicting biological impairment from habitat assessments

The goal of biological monitoring programs is to determine impairment classification and identify local stressors. Biological monitoring performs well at detecting impairment but when used alone falls short of determining the cause of the impairment. Following detection a more thorough survey is often conducted using extensive biological, chemical, and physical analysis coupled with exhaustive statistical treatments. These methods can be prohibitive for small programs that are limited by time and budget. The objective of this study was to develop a simple and useful model to predict the probability of biological impairment based on routinely collected habitat assessments. Biological communities were assessed with the Index of Biotic Integrity (IBI), and habitat was assessed with the Qualitative Habitat Evaluation Index. Two models were constructed from a validation dataset. The first predicted a binary outcome of impaired (IBI < 35) or non-impaired (IBI ≥ 35) and the second predicted a categorical gradient of impairment. Categories include very poor, poor, fair, good, and excellent. The models were then validated with an independently collected dataset. Both models successfully predicted biological integrity of the validation dataset with an accuracy of 0.84 (binary) and 0.75 (categorical). Based on the binary outcome model, 22 sites were observed to be impaired while the model predicted them to not be impaired. The categorical model misclassified 47 samples while only seven of those were misclassified by two or more categories. The impairment source was subsequently identified by known stressors. The models developed here can be easily applied to other datasets from the Eastern Corn Belt Plain to aid in stressor identification by predicting the probability of observing an impaired fish community based on habitat. Predicted probabilities from the models can also be used to support conclusions that have already been determined.     

Sustainable livelihoods and people’s vulnerability in the face of coastal hazards

The present study investigates into the link between people’s vulnerability in the face of coastal hazards and sustainable livelihoods. It focuses on the town of Borongan in the Philippines and draws on questionnaire-based surveys and focus group discussions. This research shows that local fishermen are often compelled to go out fishing despite pending typhoon or storm surge to sustain the daily needs of their family. Its also demonstrates that the capacity of these people to protect themselves from the threat is constrained by poor and fragile livelihoods. In the event of a crisis, the study argues that people resort to a range of adjustments on their daily life which is rooted in the strength and diversity of their livelihoods. To reduce people’s vulnerability and enhance capacities to face coastal hazards, the study fosters Community-Based Disaster Risk Reduction with special emphasis to sustainable livelihoods.     

Decarboxylation of cinnamic acids using a ruthenium sawhorse

The ruthenium sawhorse has proven effective in the conversion of trans-cinnamic acid, and substituted trans-cinnamic acids, giving an effective source of biobased styrene and styrene analogues. The reaction is especially versatile, as it achieves product without utilising co-reagents. However, the optimum conditions and substrate scope of the reaction remain unexplored. This report covers the decarboxylation of a series of cinnamates with different structures. Apparent activation energies ranging from 66 to 142 kJ mol^?1 were uncovered.     

HYDRAULIC GEOMETRY RELATIONSHIPS FOR URBAN STREAMS THROUGHOUT THE PIEDMONT OF NORTH CAROLINA1

ABSTRACT: Hydraulic geometry relationships, or regional curves, relate bankfull stream channel dimensions to watershed drainage area. Hydraulic geometry relationships for streams throughout North Carolina vary with hydrology, soils, and extent of development within a watershed. An urban curve that is the focus of this study shows the bankfull features of streams in urban and suburban watersheds throughout the North Carolina Piedmont. Seventeen streams were surveyed in watersheds that had greater than 10 percent impervious cover. The watersheds had been developed long enough for the streams to redevelop bankfull features, and they had no major impoundments. The drainage areas for the streams ranged from 0.4 to 110.3 square kilometers. Cross‐sectional and longitudinal surveys were conducted to determine the channel dimension, pattern, and profile of each stream and power functions were fitted to the data. Comparisons were made with regional curves developed previously for the rural Piedmont, and enlargement ratios were produced. These enlargement ratios indicated a substantial increase in the hydraulic geometry for the urban streams in comparison to the rural streams. A comparison of flood frequency indicates a slight decrease in the bankfull discharge return interval for the gaged urban streams as compared to the gaged rural streams. The study data were collected by North Carolina State University (NCSU), the University of North Carolina at Charlotte (UNC), and Charlotte Storm Water Services. Urban regional curves are useful tools for applying natural channel design in developed watersheds. They do not, however, replace the need for field calibration and verification of bankfull stream channel dimensions.     

Evaluating the Eco‐Geomorphological Condition of Restored Streams Using Visual Assessment and Macroinvertebrate Metrics

The Stream Performance Assessment (SPA), a new rapid assessment method, was applied to 93 restored, 21 impaired, 29 reference, and 13 reference streams with some incision throughout North Carolina. Principal component analysis (PCA) indicated restored streams align more closely with reference streams rather than impaired streams. Further, PCA‐based factor analysis revealed restored streams were similar to reference streams in terms of morphologic condition, but exhibited a greater range of scores relative to aquatic habitat and bedform. Macroinvertebrate sampling and GIS watershed analyses were conducted on 84 restored streams. SPA and watershed data were compared to Ephemeroptera, Plecoptera, and Trichoptera (EPT) taxa to determine which factors indicate stream health. SPA and watershed factors were used in least squares, ridge, and principal component regression (PCR) to develop a prediction model for EPT taxa. All three methods produced reasonable predictions for EPT taxa. Cross‐validation indicated ridge regression resulted in the lowest prediction error. The ridge model was then used to predict EPT taxa numbers for 21 impaired and 25 reference streams in addition to the 84 restored streams. Statistical comparisons of the predicted scores indicated urban streams (>10% impervious watershed cover) have lower expected numbers of EPT taxa. Rural restored streams have macroinvertebrate metric scores similar to those predicted for rural reference streams.     

Organogel Polymers from 10-Undecenoic Acid and Poly(vinyl acetate)

Organogels are used in a variety of high value applications including the removal of toxic solvents from aqueous environments and the time-controlled release of compounds. One of the most promising gelators is a polyvinyl polymer containing medium chain length carboxylic acids. The existing production of this product requires synthesis of vinyl esters containing medium length carboxylic chains. This starting material must be made from an expensive and low yielding transvinylation reaction, which leaves production of useful vinyl esters and, as a result, the organogels themselves, outside the realm of practical chemistry. We have developed a new, more practical production process and used it to directly synthesize a new polymer. This new process utilizes commercially available polyvinyl acetate and accomplishes the transformation with simple hydrolysis and anhydride addition steps. The new polymers form organogels with chloroform, acetone or toluene with swell ratios up to 30. They also show time-controlled release of crystal violet over a 100 h span. This new production process opens the possibility of producing organogels utilizing agricultural resources.