Techno-economic analysis of levoglucosan production via fast pyrolysis of cotton straw in China

Pyrolysis of cotton straw is a promising technology because of the large variety of chemical species that can be produced. A more promising chemical-levoglucosan, is the subject of this study. The techno-economic feasibility of producing levoglucosan via fast pyrolysis and extraction was evaluated by modeling a 200,000 dry ton cotton straw/year facility. Experimental and modeling data were gathered from recent publications and used for analysis. For the modeled feedstock handling capacity, the results indicated that levoglucosan production could reach around 18,000 ton/year. The estimated levoglucosan production cost, including byproduct credits, was $3.3 per kg. Additionally, sensitivity analysis was performed to determine the effect of variability in different system parameters on the levoglucosan production cost

Gas Chromatographic Microsystems for Airborne and Aqueous Volatile Organic Compound Determinations

New technologies offering sensitive, selective, and near-real-time identification and quantification of the individual components of complex mixtures of volatile and semi-volatile organic compounds (S/VOCs) are greatly needed in applications such as personal (worker) exposure assessment, air and water pollution monitoring, disease diagnosis, and homeland security. This dissertation describes the characterization of two prototype instruments containing core gas chromatographic microsystems (µGCs); the development and characterization of a microscale vapor extractor (µVE), and its integration with a µGC; and the development of adsorbent materials providing selective preconcentration of polar S/VOCs for use in certain µGC applications. Following a review of the background and significance of the research (Chapter 1), this dissertation then describes the design, modeling, and preliminary characterization of the µVE, which is a passive device containing microchannels and a polymer membrane that transfers dissolved VOCs from aqueous samples passed through the device to the gas phase for analysis by a downstream µGC (Chapter 2). In a proof-of-concept experiment, a hybrid µVE-µGC microsystem extracted four VOCs from a 700 µL sample of synthetic urine in 3.5 min, and then separated, identified, and quantified each VOC in ~80 sec with a projected detection limit as low as 660 parts-per-billion. The hybrid μVE-μGC microsystem may eventually permit rapid field/clinical analyses of water contaminants and urinary biomarkers of exposure and disease. Chapters 3 and 4 describe prototype µGC instruments that are referred to as Personal Exposure Monitoring Microsystems (PEMM-1 and PEMM-2, respectively). PEMM-1 is a laptop-controlled, AC-powered, compact, bench-top unit and PEMM-2 is a battery-powered, belt-mounted unit with embedded controll. Both contain analytical microsystems made from Si-microfabricated components: a dual-adsorbent µpreconcentrator-focuser, a single- or dual-μcolumn separation module, and a μsensor-array detector. The μsensor-array consists of 4-5 chemiresistors (CR) coated with various monolayer-protected Au nanoparticles (MPN), which collectively yield partially selective response patterns that can enhance the recognition/discrimination of VOCs. Other key components include a pre-trap for low-volatility interferences, a split-flow injection valve, and an onboard He carrier-gas canister. In laboratory tests, PEMM-1 demonstrated the determination of 17 VOCs in the presence of 7 background interferences in 8 min. Detection limits were below the corresponding Threshold Limit Values (TLV) of the VOCs. PEMM-2 demonstrated the direct, autonomous determination of 21 VOCs in 6 min, with detection limits ranging from 16−600 ppb, well below TLV levels. A chemometric strategy involving retention time windows was implemented that greatly facilitated vapor recognition and discrimination via the µsensor-array response patterns. Results from a “mock” field test, in which personal exposures to time-varying concentrations of a mixture of five VOCs were measured autonomously, agreed closely with those from a reference GC. Chapter 5 describes the use of a trigonal-tripyramidal room-temperature ionic liquid (RTIL) as a surface modifier for the graphitized carbons, Carbopack B (C-B) and Carbopack X (C-X), used as µpreconcentrator adsorbents. The goal was to impart selectivity for polar compounds, particularly organophosphates and their precursors. Results showed that the capacities for five organophosphorus vapors were consistently enhanced ~2.5-fold with the RTIL-treated adsorbents relative to the untreated adsorbents. Furthermore, the capacities for several non-polar reference vapors were reduced 11 to 26-fold with the modified adsorbents. Implementation in next-generation µpreconcentrator devices is planned.PHDChemistryUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttps://deepblue.lib.umich.edu/bitstream/2027.42/151661/1/wjunqi_1.pd

Multi-TGDR, a multi-class regularization method, identifies the metabolic profiles of hepatocellular carcinoma and cirrhosis infected with hepatitis B or hepatitis C virus

BACKGROUND: Over the last decade, metabolomics has evolved into a mainstream enterprise utilized by many laboratories globally. Like other “omics” data, metabolomics data has the characteristics of a smaller sample size compared to the number of features evaluated. Thus the selection of an optimal subset of features with a supervised classifier is imperative. We extended an existing feature selection algorithm, threshold gradient descent regularization (TGDR), to handle multi-class classification of “omics” data, and proposed two such extensions referred to as multi-TGDR. Both multi-TGDR frameworks were used to analyze a metabolomics dataset that compares the metabolic profiles of hepatocellular carcinoma (HCC) infected with hepatitis B (HBV) or C virus (HCV) with that of cirrhosis induced by HBV/HCV infection; the goal was to improve early-stage diagnosis of HCC. RESULTS: We applied two multi-TGDR frameworks to the HCC metabolomics data that determined TGDR thresholds either globally across classes, or locally for each class. Multi-TGDR global model selected 45 metabolites with a 0% misclassification rate (the error rate on the training data) and had a 3.82% 5-fold cross-validation (CV-5) predictive error rate. Multi-TGDR local selected 48 metabolites with a 0% misclassification rate and a 5.34% CV-5 error rate. CONCLUSIONS: One important advantage of multi-TGDR local is that it allows inference for determining which feature is related specifically to the class/classes. Thus, we recommend multi-TGDR local be used because it has similar predictive performance and requires the same computing time as multi-TGDR global, but may provide class-specific inference

The Development of NBA in China: A Glocalization Perspective

The growing sport industry and 1.3 billion potential consumers in China have been garnering tremendous attention from more and more overseas professional sport leagues. Comparatively, the National Basketball Association (NBA) has had remarkable success in the Chinese market. From the perspective of sport competition or marketing operations, the NBA’s achievement in China provides a model for other overseas sport leagues. This case study was organized by summarizing the developmental history of NBA in China, analyzing its current promotional practices, investigating into its marketing strategies, and extrapolating practical references for other sport leagues aiming to penetrating into the Chinese marketplace. In the perspective of glocalization, multinational corporations should combine both standardized and adapted elements to conceptualize globally and act locally (Tanahashi, 2008). By taking this approach, marketers can meet the needs of local consumers effectively while still maintaining some extent of global standardization (Singh, Kumar, & Baack, 2005). To obtain in-depth understanding about NBA globalization and localization in China, we conducted one-on-one interviews with Chinese academic scholars in sport management and practitioners in Chinese basketball industry and NBA China. Two focus groups with six participants in each group were conducted to learn the perception of NBA products from the perspective of Chinese consumer. The qualitative data analysis was organized around four major aspects: products, media, management and public relations, which were highlighted in the glocalization of transnational corporations (Yang, 2003; Zhang, 2007) The current case study concluded that although NBA has achieved huge successes in the areas of building a large fan base, increasing media exposure, and garnering net income after its entry to China, it still faces many challenges. One viable solution for the NBA is to bring authentic American cultural commodities while adding Chinese characteristics to accommodate local fans. Combining global heroes such as Michael Jordan and Kobe Bryant and local hero such as Yao Ming, Yi Jianlian, and Jeremy Lin, NBA games will continue to appeal to millions of Chinese fans. Meantime, NBA management needs to continue seeking ways to work out and through the differences in government models and cultural contexts between China and United States. Some viable actions include the promotion of Chinese youth basketball, the training service for elite basketball players, and government-level public relations. In addition, this study suggested that the research framework of glocalization would be an ever intriguing inquiry needed for other sport organizations or leagues seeking expansion to overseas markets