Minimizing water and energy consumptions in water and heat exchange networks.

This study presents a mathematical programming formulation for the design of water and heat exchangers networks based on a two-step methodology. First, an MILP (mixed integer linear programming) procedure is used to solve the water and energy allocation problem regarding several objectives. The first step of the design method involves four criteria to be taken into account., ie, fresh water consumption (F1), energy consumption (F2), interconnection number (F3) and number of heat exchangers (F4). The multiobjective optimization Min [F1, F2] is solved by the so-called ɛ-constraint method and leads to several Pareto fronts for fixed numbers of connections and heat exchangers. The second step consists in improving the best results of the first phase with energy integration into the water network. This stage is solved by an MINLP procedure in order to minimize an objective cost function. Two examples reported in the dedicated literature serve as test bench cases to apply the proposed two-step approach. The results show that the simultaneous consideration of the abovementioned objectives is more realistic than the only minimization of fresh water consumption. Indeed, the optimal network does not necessarily correspond to the structure that reaches the fresh water target. For a real paper mill plant, energy consumption decreases of almost 20% as compared with previous studies

Tuning Proton Conductivity Properties of Lanthanide Amino-Sulfophosphonates-Loaded Nafion Composite Membranes

Polymer-based electrolytes in proton exchange membrane fuel cells (PEMFCs) utilize acidic groups as proton carriers and hydrogen bonding networks as proton-conducting pathways to facilitate proton transport. Crystalline acid-functionalized metal phosphonates are potential proton conductors while maintaining a high hydration degree below 100 °C. This property may be combined with Nafion-like polymers which tend to dehydrate at the operating conditions of PEMFCs [1,2]. In this work, preliminary results of the preparation of lanthanide amino-sulfophosphonates-loaded Nafion composites membranes and the corresponding electrical properties are reported. Synthesis conditions of lanthanide derivatives were optimized following a hightrough-put screening at 140 °C. Their crystal structures, solved from synchrotron X-ray powder diffraction data, corresponds to layered frameworks where the acidic groups, -CPO3H or -SO3H, point toward the interlamellar region interacting by H-bond with the lattice water. The composites were prepared by mixing the metal phosphonates with Nafion solution at different loadings. The membranes were characterized by SEM, XRD and FT-IR. A study of the proton conductivity as a function of the composite membranes was carried out at 90 °C and 95% RH. Referencias [1] Y. Gao, R. Broersen, W. Hageman, N. Yan, M. C. Mittelmeijer-Hazeleger, G. Rothenberg, S. Tanase. J. Mater. Chem. A, 2015, 3, 22347–22352. [2] A. Cabeza, P. Olivera-Pastor, R. M. P. Colodrero. Tailored Organic-Inorganic Materials, Brunet, E., Colón, J.L., Clearfield, A., Eds.; John Wiley & Sons, Inc. 2015; Ch. 4, 137−191.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Phase separation and self-assembly in vitrimers: hierarchical morphology of molten and semi-crystalline polyethylene/dioxaborolane maleimide systems

Vitrimers - a class of polymer networks which are covalently crosslinked and insoluble like thermosets, but flow when heated like thermoplastics - contain dynamic links and/or crosslinks that undergo an associative exchange reaction. These dynamic crosslinks enable vitrimers to have interesting mechanical/rheological behavior, self-healing, adhesive, and shape memory properties. We demonstrate that vitrimers can self-assemble into complex meso- and nanostructures when crosslinks and backbone monomers strongly interact. Vitrimers featuring polyethylene (PE) as the backbone and dioxaborolane maleimide as the crosslinkable moiety were studied in both the molten and semi-crystalline states. We observed that PE vitrimers macroscopically phase separated into dioxaborolane maleimide rich and poor regions, and characterized the extent of phase separation by optical transmission measurements. This phase separation can explain the relatively low insoluble fractions and overall crystallinities of PE vitrimers. Using synchrotron-sourced small-angle X-ray scattering (SAXS), we discovered that PE vitrimers and their linear precursors micro-phase separated into hierarchical nanostructures. Fitting of the SAXS patterns to a scattering model strongly suggests that the nanostructures - which persist in both the melt and amorphous fraction of the semi-crystalline state - may be described as dioxaborolane maleimide rich aggregates packed in a mass fractal arrangement. These findings of hierarchical meso- and nanostructures point out that incompatibility effects between network components and resulting self-assembly must be considered for understanding behavior and the rational design of vitrimer materials

Open Science principles for accelerating trait-based science across the Tree of Life.

Synthesizing trait observations and knowledge across the Tree of Life remains a grand challenge for biodiversity science. Species traits are widely used in ecological and evolutionary science, and new data and methods have proliferated rapidly. Yet accessing and integrating disparate data sources remains a considerable challenge, slowing progress toward a global synthesis to integrate trait data across organisms. Trait science needs a vision for achieving global integration across all organisms. Here, we outline how the adoption of key Open Science principles-open data, open source and open methods-is transforming trait science, increasing transparency, democratizing access and accelerating global synthesis. To enhance widespread adoption of these principles, we introduce the Open Traits Network (OTN), a global, decentralized community welcoming all researchers and institutions pursuing the collaborative goal of standardizing and integrating trait data across organisms. We demonstrate how adherence to Open Science principles is key to the OTN community and outline five activities that can accelerate the synthesis of trait data across the Tree of Life, thereby facilitating rapid advances to address scientific inquiries and environmental issues. Lessons learned along the path to a global synthesis of trait data will provide a framework for addressing similarly complex data science and informatics challenges

An exploration of embeddedness : with special reference to Japan : a thesis presented in partial fulfilment of the requirements for the degree of Master of Arts in Economics at Massey University

This thesis utilises the economic sociology concept of embeddedness as the theoretical underpinning to provide an alternative perspective to traditional explanations of economic growth. In general, the advantages of social embeddedness have been the main focus in the literature on the topic. The main purpose of this study is to explore, with special reference to Japan, how embedded relationships could both enable and hinder growth. The study examines the operation of embedded ties in four key areas: inter-firm interaction with an emphasis on the auto-industry; embedded relationships within the financial sector; networks in the internationalisation of firms and embeddedness between government and business, including a case study of the construction industry. It finds that while embedded ties have several advantageous facets, they also have the potential to be an impediment to growth, flexibility and adaptability to change. Network ties can expand and become so rigidly structured, especially in a Confucian society like Japan, as to become obstacles particularly in the face of changing economic circumstances. They can atrophy. This finding led to the development of the concluding notion of "atrophied embeddedness"

Testing theory in interprofessional education: Social capital as a case study

Theory is essential to understand our interprofessional educational (IPE) practice. As a discipline, IPE has moved from being widely atheoretical to having a plethora of theories imported from the psychosocial disciplines that have utility to understand, articulate and improve IPE practice and evaluation. This paper proposes that when taking this deductive approach to theoretical development in IPE, a greater focus must now be placed on the rigorous testing of these theories within the IPE context. It synthesizes two approaches to achieving this, using the social capital theory as a case study, and focuses on the first two stages of this synthesis: first, the identification of the concepts and propositions that make up a theory within the study context and second, the value-based judgments made by the researcher and other stakeholders on the utility of these propositions. The interprofessional student group is chosen as a possible exemplar of a social network and theory-derived concepts and propositions are identified and classified within this context. With a focus on physical network characteristics, validation of these propositions with a sample of IPE educationalists is described. We present a range of propositions specifically related to the size and mix of IPE student groups, the frequency and level with which students participate in these as well as some of the existing evidence that have explored these propositions to date. Refined propositions and the way forward in the future application and empirical testing of social capital theory in IPE are presented

Advanced information processing system for advanced launch system: Avionics architecture synthesis

The Advanced Information Processing System (AIPS) is a fault-tolerant distributed computer system architecture that was developed to meet the real time computational needs of advanced aerospace vehicles. One such vehicle is the Advanced Launch System (ALS) being developed jointly by NASA and the Department of Defense to launch heavy payloads into low earth orbit at one tenth the cost (per pound of payload) of the current launch vehicles. An avionics architecture that utilizes the AIPS hardware and software building blocks was synthesized for ALS. The AIPS for ALS architecture synthesis process starting with the ALS mission requirements and ending with an analysis of the candidate ALS avionics architecture is described

Understanding Evidence-Based Interventions for Cross-Cultural Group Work: A Learning Analytics Perspective

As the numbers of international students worldwide continue to rise, one common challenge is how best to socially integrate diverse groups of students. Indeed, research demonstrates that many students form social and learning relationships with those from the same cultural background, despite benefits of cross-cultural communication. This lack of social cohesion negatively affects students, particularly when it comes to their perceptions of collaborative group work. However, few studies have analysed measurable student behaviours in group work, such as with learning analytics, to determine how culture and existing social networks influence measurable differences in contributions. Similarly, little is known about what evidence-based interventions lead to more equal participation between diverse students. In this research, learning analytics is combined with social network analysis to determine the role of social connections on group work participation, and highlight replicable interventions that can help promote social cohesion in diverse classrooms