Zirconium diboride (ZrB2) ceramics were densified by pressureless sintering (PS), hot pressing, or spark plasma sintering (SPS) of powders with a range of starting particle sizes and oxygen contents. Microstructural analysis of the ZrB2 ceramics revealed a wide range of final grain sizes. SPS resulted in an average grain size as small as 1.6 μm after densification at 1900°C, while the largest grains, 31 μm, were produced by PS at 2100°C. Oxygen impurities in boride ceramics caused grain coarsening in all densification techniques, but inhibited full densification only for PS. Carbon was added to react with and remove oxygen impurities, which promoted densification, reduced ZrB2 grain size, and led to increased room‐temperature flexure strengths. The highest strength was 527 MPa for SPS ZrB2, while the lowest strength was measured for pressurelessly sintered ZrB2, 300 MPa. Overall, SPS was the superior technique for providing the highest strength and greatest ability to remove oxygen.

The thermal properties of zirconium diboride (ZrB2) ceramics with carbon additions of up to 3 wt% were characterized up to 2000°C. Carbon contents were selected to produce ZrB2 that was nominally pure, contained dissolved carbon, or contained carbon inclusions. The microstructure and density changes that resulted from the carbon additions affected the thermal behavior of ZrB2 at room and elevated temperatures. Thermal diffusivity at 200°C increased from 0.150 cm2/s for nominally pure ZrB2 to 0.175 cm2/s for ZrB2 with 3 wt% carbon. The thermal diffusivity decreased with increasing temperature, reaching a value of 0.143 cm2/s at 2000°C for ZrB2 with 3 wt% carbon. In addition, thermal diffusivity changed irreversibly during the first thermal cycle after densification due to changes in the microstructure that started between 1550°C and 1650°C. Heating resulted in the formation of a new phase, growth of ZrB2 grains, changes in the morphology of carbon inclusions, and migration of W impurities from the ZrB2 matrix into the new phase. Heat capacity, unlike thermal diffusivity, did not change during thermal cycling. Thermal conductivity, which was calculated from thermal diffusivity, heat capacity, and density, was as high as 64.2 W·(m·K)−1 at 2000°C for ZrB2 with 3 wt% carbon. The phonon contribution to thermal conductivity decreased to nearly zero with the addition of 3 wt% carbon due to the presence of elongated carbon inclusions around ZrB2 grains.

To enable small communities to benchmark the energy efficiency of their water resource recovery facilities (also known as wastewater treatment facilities), multiple linear regression models of electric and overall energy intensity (kWh/m3) were created using data from Nebraska and Pennsylvania. Key variables found to be significant include: facility type, supplemental energy usage for sludge treatment, average flow, percent design flow, climate controlled floor area, effluent NH3-N, and influent CBOD5. The results show that energy use models for small systems differ from those for large facilities and that regulatory changes can affect energy usage. Step changes in the data for facilities that changed operators highlight the importance of operational decisions on energy efficiency for small facilities serving fewer than 10,000 people. Differences were observed between the models of data from specific states. Although these models may not include all factors that account for variability in energy use, they can provide a reference benchmark for small WRRFs.

This study investigates the differences between field-based odor assessment methods that may be used to discriminate odors from livestock and food processing facilities. Field olfactometers have been praised for their low cost ($500 -$1200) and portability but criticized for their lack of control of inhalation rates by different panelists, the discomfort of glass inhalation tubes and the odor fatigue caused by poor nasal sealing or removing the scentometer between samples as compared to laboratory dynamic, triangular forcedchoice olfactometers ($30,000). This study evaluated the variability of responses using these three field olfactometers compared to laboratory olfactometry, as well as field and lab odor intensity. Panel responses using laboratory dynamic, triangular force-choice olfactometry and Nasal Ranger field olfactometers were found to exhibit the least amount of variability across odor sources. Significant differences with poor correlation were found between field and laboratory odor intensity methods. Findings of this study should caution regulators, policy makers and investigators about establishing regulatory thresholds or reporting scientific data based on single odor analysis methods or techniques due to the variability in the performance of odor determination methods across the odorous sites investigated.

Details the results of a new study of European businesses by PIMS Associates and the Chartered Institute of Purchasing and Supply, which highlights the value of a good purchasing strategy, and reveals that very few businesses monitor and look towards developing their purchasing activity. Describes the use of comprehensive cross‐industry benchmarking to assess the effectiveness of a company’s procurement function. Lists the key findings of the survey, and suggests that businesses which invest in making improvements to their supply chain management can significantly increase productivity and profits and achieve leading‐edge company status.