1,721,014 research outputs found
Doping level and work function control in oxidative chemical vapor deposited poly (3,4-ethylenedioxythiophene)
No full textControl over doping level and work function is achieved for poly(3,4-ethylenedioxythiophene) (PEDOT) films deposited by oxidative chemical vapor deposition (oCVD). Surface analysis reveals the equivalence of the surface and bulk compositions for the oCVD films. The oCVD PEDOT polymer chains doped solely with Cl- ions. By increasing the substrate temperature used for deposition, the doping level was monotonically increased from 17 to 33 at. %, resulting in a corresponding ability to tune the work function from 5.1 to 5.4 eV. The controllability of doping level and work function of oCVD PEDOT offers great potential advantages for organic devices. (c) 2007 American Institute of Physics.This research was supported by, or supported in part by,
the U.S. Army through the Institute for Soldier Nanotechnologies,
under Contract No. DAAD-19-02-D-0002 with the
U.S. Army Research Office. The authors thank Anthony
Garrett-Reed for the STEM measurement. The authors thank
LG Chemicals Ltd. for the measurement of work function
Industrial Symbiosis Among Small and Medium Scale Enterprises: Case of Muzaffarnagar, India
No full textDeveloping countries like India, characterized by large working populations and significantly lower cost of capital, have become hotbeds for manufacturing activities. A distinctive feature in regions of India is that majority of the industrial material flows are through unorganized micro, small and medium scale enterprises (MSMEs). These highly constrained MSMEs have limited resources to comply with environmental regulations because of significant investments required in pollution control measures. An important way to improve the environmental performance of these industrial clusters is to quantify, treat, and reduce industrial byproducts. This objective could be achieved through industrial symbiosis or byproduct synergy, terms used for beneficial reuse of materials or energy streams from one facility by another. In the present study an attempt has been made to identify and understand existing and potential industrial symbiosis connections in Muzaffarnagar, an industrial town in north India home to several dozen paper mills, another dozen sugar mills, and a large range of other MSME manufacturing entities. In addition to the presence of small and medium enterprises there is also a strong bond between industry owners in the region. Keywords: Industrial symbiosis, small and medium enterprise
Understanding dynamic availability risk of critical materials: The role and evolution of market analysis and modeling
No full textMany advanced energy technologies are fundamentally “materials-dependent”; they are enabled directly by, or designed around, a particular material or materials. Society's acute dependence on materials has increased in recent years as these technologies tap into an ever broader range of the periodic table and, therefore, into a broader set of underdeveloped and complex supply chains. Ultimately, concern around the supply of materials strategic to energy and security interests has led to the development of a range of systems used to assess criticality—the confluence of vulnerability and risk. Concerning the assessment of criticality risk, this review accomplishes two primary goals. First, through a review of several broad assessments of criticality metrics, we identify those metrics that incorporate assessment of future production and consumption. We review the methods that have been applied to project production and consumption along two axes, one around degree of detail or granularity pursued by the model and the second around the degree to which market function is modeled endogenously. Regarding the second, material projection methods can be broadly classified as (a) those which project material flows only and (b) those which use market modeling to explicitly simulate (endogenously) the associated economic behavior and its implication on material flows
Data Mining Toward Increased Use of Aluminum Dross
No full textRecycling provides a key strategy to move toward a more sustainable society by partially mitigating the impact of fast-growing material consumption. One main barrier to increased recycling arises from the fact that in many real world contexts, the quality of secondary (or scrap) material is unknown and highly variable. Even if scrap material is of known quality, there may be finite space or limited operational flexibility to separate or sort these materials prior to use. These issues around identification and grouping given the operational constraints create limitations to simply developing an appropriate sorting strategy, let alone implementing one. This study suggests the use of data mining as a strategy to manage raw materials with uncertain quality using existing data from the recycling industry. A clustering analysis is used to recognize the pattern of raw materials across a broad compositional range in order to provide criteria for grouping (binning) raw materials. This strategy is applied to an industrial case of aluminum recycling to explore the benefits and limitations in terms of secondary material usage. In particular, the case investigated is around recycling industrial byproducts (termed dross for the case of the aluminum industry). The binning strategy obtained by the clustering analysis can significantly reduce material cost by increasing the compositional homogeneity and distinctiveness of uncertain raw materials. This result suggests the potential opportunity to increase low-quality secondary raw material usage before investment in expensive sorting technology.Norsk Hydr
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Operational Strategies for Increasing Secondary Materials in Metals Production Under Uncertainty
No full textIncreased use of secondary raw materials in metal production offers several benefits including reduced cost and lowered energy burden. The lower cost of secondary or scrap materials is accompanied by an increased uncertainty in elemental composition. This increased uncertainty for different scraps, if not managed well, results in an increased risk that the elemental concentrations in the final products fall outside customer specifications. Previous results show that incorporating this uncertainty explicitly into batch planning can modify the potential use of scrap materials while managing risk. Chance-constrained formulations provide one approach to uncertainty-aware batch planning; however, typical formulations assume normal distributions to represent the compositional uncertainty of the materials. Compositional variation in scrap materials has been shown to have a skewed distribution, and therefore, the performance of these models, in terms of their ability to provide effective planning, it may then be heavily influenced by the structure of the compositional data used. To address this issue, this work developed several approximations for skewed distributional forms within chance-constrained formulations. We explored a lognormal approximation based on Fenton’s method; a convex approximation based on Bernstein inequalities; and a linear approximation using fuzzy set theory. Each of these methods was formulated and case studies executed using compositional data from an aluminum remelter. Results indicate that the relationship between the underlying structure/distribution of the compositional data and how these distributions are formulated in batch planning can modify the use of secondary raw materials.National Science Foundation (U.S.) (Award 1133422
A Methodology for Robust Comparative Life Cycle Assessments Incorporating Uncertainty
No full textWe propose a methodology for conducting robust comparative life cycle assessments (LCA) by leveraging uncertainty. The method evaluates a broad range of the possible scenario space in a probabilistic fashion while simultaneously considering uncertainty in input data. The method is intended to ascertain which scenarios have a definitive environmentally preferable choice among the alternatives being compared and the significance of the differences given uncertainty in the parameters, which parameters have the most influence on this difference, and how we can identify the resolvable scenarios (where one alternative in the comparison has a clearly lower environmental impact). This is accomplished via an aggregated probabilistic scenario-aware analysis, followed by an assessment of which scenarios have resolvable alternatives. Decision-tree partitioning algorithms are used to isolate meaningful scenario groups. In instances where the alternatives cannot be resolved for scenarios of interest, influential parameters are identified using sensitivity analysis. If those parameters can be refined, the process can be iterated using the refined parameters. We also present definitions of uncertainty quantities that have not been applied in the field of LCA and approaches for characterizing uncertainty in those quantities. We then demonstrate the methodology through a case study of pavements
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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