Teaching sustainability: does style matter?

Purpose: This paper aims to analyze how a tangram activity improved students' abilities to explain sustainability, articulate a positive perception of sustainable design and relate sustainability with innovation in engineering design.

Design/methodology/approach: The concept of paradigm shift was introduced in the classroom by using a tangram activity to help students understand that sustainable design requires out-of-the-box thinking. Instructors from three institutions teaching various levels of sustainability courses to engineering majors used the activity to introduce sustainable design, then measured the understanding and appreciation of the concepts introduced through the tangram activity with pre- and post-activity surveys.

Residential proximity to high-density poultry operations associated with campylobacteriosis and infectious diarrhea.

Poultry carry zoonotic bacteria that can cause gastroenteritis in humans. Environmental transmission of pathogens from poultry operations may increase gastrointestinal infection risk in surrounding communities. To evaluate associations between residential proximity to high-density poultry operations and individual-level diarrheal illnesses, we conducted a nested case-control study among 514,488 patients in Pennsylvania (2006-2015).

Prospects for energy recovery during hydrothermal and biological processing of waste biomass.

Thermochemical and biological processes represent promising technologies for converting wet biomasses, such as animal manure, organic waste, or algae, to energy. To convert biomass to energy and bio-chemicals in an economical manner, internal energy recovery should be maximized to reduce the use of external heat and power. In this study, two conversion pathways that couple hydrothermal liquefaction with anaerobic digestion or catalytic hydrothermal gasification were compared.

Target Cultivation and Financing Parameters for Sustainable Production of Fuel and Feed from Microalgae.

Production of economically competitive and environmentally sustainable algal biofuel faces technical challenges that are subject to high uncertainties. Here we identify target values for algal productivity and financing conditions required to achieve a biocrude selling price of $5 per gallon and beneficial environmental impacts. A modeling framework--combining process design, techno-economic analysis, life cycle assessment, and uncertainty analysis--was applied to two conversion pathways: (1) "fuel only (HTL)", using hydrothermal liquefaction to produce biocrude, heat and power, and (2) "fuel and feed", using wet extraction to produce biocrude and lipid-extracted algae, which can substitute components of animal and aqua feeds.

Quantitative uncertainty analysis of Life Cycle Assessment for algal biofuel production.

As a result of algae's promise as a renewable energy feedstock, numerous studies have used Life Cycle Assessment (LCA) to quantify the environmental performance of algal biofuels, yet there is no consensus of results among them. Our work, motivated by the lack of comprehensive uncertainty analysis in previous studies, uses a Monte Carlo approach to estimate ranges of expected values of LCA metrics by incorporating parameter variability with empirically specified distribution functions. Results show that large uncertainties exist at virtually all steps of the biofuel production process.

Using FTIR spectroscopy to model alkaline pretreatment and enzymatic saccharification of six lignocellulosic biomasses.

Fourier transform infrared, attenuated total reflectance (FTIR-ATR) spectroscopy, combined with partial least squares (PLS) regression, accurately predicted solubilization of plant cell wall constituents and NaOH consumption through pretreatment, and overall sugar productions from combined pretreatment and enzymatic hydrolysis. PLS regression models were constructed by correlating FTIR spectra of six raw biomasses (two switchgrass cultivars, big bluestem grass, a low-impact, high-diversity mixture of prairie biomasses, mixed hardwood, and corn stover), plus alkali loading in pretreatment, to nine dependent variables: glucose, xylose, lignin, and total solids solubilized in pretreatment; NaOH consumed in pretreatment; and overall glucose and xylose conversions and yields from combined pretreatment and enzymatic hydrolysis. PLS models predicted the dependent variables with the following values of coefficient of determination for cross-validation (Q²): 0.

Using FTIR to predict saccharification from enzymatic hydrolysis of alkali-pretreated biomasses.

Fourier transform infrared, attenuated total reflectance (FTIR-ATR) spectroscopy combined with partial least squares (PLS) regression accurately predicted 72-h glucose and xylose conversions (g sugars/100 g potential sugars) and yields (g sugars/100 g dry solids) from cellulase-mediated hydrolysis of alkali-pretreated lignocellulose. Six plant biomasses that represent a variety of potential biofuel feedstocks--two switchgrass cultivars, big bluestem grass, a low-impact, high-diversity mixture of 32 species of prairie biomasses, mixed hardwood, and corn stover--were subjected to four levels of low-temperature NaOH pretreatment to produce 24 samples with a wide range of potential digestibility. PLS models were constructed by correlating FTIR spectra of pretreated samples to measured values of gluose and xylose conversions and yields.

Assessment of commercial hemicellulases for saccharification of alkaline pretreated perennial biomass.

The objective of this research was to measure the effects of different cellulase and hemicellulase mixtures on fermentable sugar production from two different perennial biomasses--switchgrass and a low-impact, high-diversity prairie biomass mixture (LIHD). Each was subjected to NaOH pretreatment, followed by hydrolysis with a commercial cellulase and β-glucosidase mixture [CB] supplemented with either of two hemicellulases. For both biomasses, there was little gain in sugar yield when using CB alone beyond 20-25 mg/g TS; further gain in yield was possible only through hemicellulase supplementation.