Scaling carbon sequestration phenomena to the earth's surface

We present a computational framework for fast monitoring of fault stability and ground deformation in multiphase geomechanics and demonstrate its efficacy for a carbon sequestration--enhanced oil recovery case study. The staggered solution algorithm for the coupled problem is augmented with a feature that allows for the flow and geomechanics sub-problems to be solved on different unstructured tetrahedral grids. For the field scale problem, the geomechanics grid goes all the way to the free surface while the flow grid is truncated at a depth above which the layers are impermeable. This framework avoids the unnecessary computational burden associated with equilibrating the initial pressure solution in the overburden, allows for a study of the critical interaction between overburden and faults, allows for fast renditions of ground deformation, and allows a choice of resolution for the flow and geomechanics grids independently to capture disparate length scales of the underlying physics.

Development of a mesoscopic framework spanning nanoscale protofibril dynamics to macro-scale fibrin clot formation

Thrombi form a micro-scale fibrin network consisting of an interlinked structure of nanoscale protofibrils, resulting in haemostasis. It is theorized that the mechanical effect of the fibrin clot is caused by the polymeric protofibrils between crosslinks, or to their dynamics on a nanoscale order. Despite a number of studies, however, it is still unknown, how the nanoscale protofibril dynamics affect the formation of the macro-scale fibrin clot and thus its mechanical properties. A mesoscopic framework would be useful to tackle this multi-scale problem, but it has not yet been established. We thus propose a minimal mesoscopic model for protofibrils based on Brownian dynamics, and performed numerical simulations of protofibril aggregation. We also performed stretch tests of polymeric protofibrils to quantify the elasticity of fibrin clots. Our model results successfully captured the conformational properties of aggregated protofibrils, e.g., strain-hardening response. Furthermore, the results suggest that the bending stiffness of individual protofibrils increases to resist extension.

Enabling Multi-Robot Cooperative Additive Manufacturing: Centralized vs. Decentralized Approaches

This paper presents a decentralized approach based on a simple set of rules to carry out multi-robot cooperative 3D printing. Cooperative 3D printing is a novel approach to 3D printing that uses multiple mobile 3D printing robots to print a large part by dividing and assigning the part to multiple robots in parallel using the concept of chunk-based printing. The results obtained using the decentralized approach are then compared with those obtained from the centralized approach. Two case studies were performed to evaluate the performance of both approaches using makespan as the evaluation criterion. The first case is a small-scale problem with four printing robots and 20 chunks, whereas the second case study is a large-scale problem with ten printing robots and 200 chunks. The result shows that the centralized approach provides a better solution compared to the decentralized approach in both cases in terms of makespan. However, the gap between the solutions seems to shrink with the scale of the problem. While further study is required to verify this conclusion, the decrease in this gap indicates that the decentralized approach might compare favorably over the centralized approach for a large-scale problem in manufacturing using multiple mobile 3D printing robots. Additionally, the runtime for the large-scale problem (Case II) increases by 27-fold compared to the small-scale problem (Case I) for the centralized approach, whereas it only increased by less than 2-fold for the decentralized approach.

APPLICATION OF MULTIPLE CRITERIA DECISION MAKING METHODS IN CONSTRUCTION: A SYSTEMATIC LITERATURE REVIEW

Decision making is a key to business or project success in any sectors, especially in construction that requires handling numerous information and knowledge. Multiple criteria decision making (MCDM) is an important tool for decision problem solving due to simultaneous consideration of multiple criteria and objectives. Various MCDM methods are continually emerging and tend to be increasingly adopted to address the real-world construction problems. Therefore, it is urged to systematically review the existing body of literature to demonstrate the evolution of the mainstream MCDM methods in general and their application status in construction. A total of 530 construction articles published from 2000 to 2019 are selected in this study and then categorized into seven major application areas using a novel systematic literature review (SLR) methodology. The bibliometric analysis is then used to describe the research trend. Subsequently, the qualitative discussion by themes is conducted to analyze the application of MCDM methods in construction. A further discussion makes it possible to identify the potential challenges (e.g. applicability, robustness, postpone effect, dynamic and prospective challenges and scale problem) to existing research. It also contributes to the recommendation of future directions for the development of MCDM methods that would benefit construction research and practice.

Reported Lead Levels in Different Environmental Matrices in Colombia

Objective: The aim of this paper is to present a review of specific cases that reported lead concentrations in blood, objects, food, soil, bioindicators, air, and water in specific places in Colombia and evaluate the reported concentrations against target values. Materials and Methods: A systematic qualitative literature review of publications between 1995 and 2019 was done; using Boolean operators 1571 papers were identified, to which 3 inclusion and 4 exclusion criteria were applied. A total of 57 studies met the defined criteria. The reports in these studies were geo-localized and compared with acceptable values. Results and Discussion: Results suggest that lead is present in all environmental matrices, widely distributed in the Colombian territory, and that 72 % of the cases exceeded regulation limits. The percentage of noncompliance per environmental matrix was 89 % for blood samples, 71 % in food, 63 %, in soil, 89 % for bioindicators, 60 % for air, and 55 % for water. Conclusion: These results show that lead pollution is a large-scale problem in the country, more systematic studies are needed, and control measures, policy-making and regulatory updating should be pursued.

PROBLEMATIZAÇÕES CONTEMPORÂNEAS SOBRE A ESCALARIDADE: FORMA, NATUREZA E ORGANIZAÇÃO DAS ESCALAS GEOGRÁFICAS

O “problema da escala” emerge na Geografia no momento em que a necessidade de organizar as unidades espaciais possíveis de serem identificadas é ressaltada como uma preocupação metodológica, sendo assim explicitado e tratado no âmbito acadêmico da Geografia sobretudo a partir da década de 1950. A difusão de certos referenciais teórico-políticos nas pesquisas sócio-espaciais possibilitou que a questão escalar fosse, nos anos seguintes, observada desde abordagens para as quais dividir e organizar o espaço não era uma questão meramente metodológica, mas também epistemológica, política e, portanto, diretamente ligada à prática e à ação social. Mas a proliferação de trabalhos sobre as escalas geográficas não ocorreu homogeneamente nos diferentes ambientes linguísticos da literatura especializada. No caso anglófono, foi a partir do final da década de 1980 que isso aconteceu, processo que ficou conhecido como de “abertura” do conceito de escala na Geografia. O objetivo destas páginas é caracterizar os principais eixos do debate sobre as escalas geográficas que se desenrolou entre aproximadamente a última década do século XX e a primeira década do século XXI nas pesquisas realizadas no ambiente da Geografia anglófona de forma a incrementar a pluralidade de questões que fertilizam as compreensões sobre a escala geográfica.Palavras-chave: Escala geográfica; História do Pensamento Geográfico; Geografia anglófona. CONTEMPORARY TOPICS ON SCALARITY: FORM, NATURE, AND ORGANISATION OF GEOGRAPHICAL SCALESAbstract: The “scale problem” emerges in Geography at the moment in which the need to organize the possibly identifiable spatial units is highlighted as a methodological concern. Thus, it became explicit and treated in this academic field, specially from the 1950s onward. In the following years the diffusion of other theoretical-political references in Western socio-spatial research allowed the scalar issue to be observed from approaches for which the act of divide and organize the space was not merely a methodological issue, but also an epistemological and political one ―and, therefore, scale was recognized as directly linked to the practice and social action. But the proliferation of works on geographical scales did not occur homogeneously in the different linguistic environments of the specialized literature. In the Anglophone case, for example, it was from the end of the 1980s that this happened. The aim of this article is to characterize the main axes of the debate on geographical scales that took place between approximately the last decade of the twentieth century and the first decade of the twenty-first century in the research carried out in the environment of Anglophone Geography in order to increase the plurality of issues that fertilize the understandings on geographical scale.Keywords: Geographical scale; History of Geographical Thought; Anglophone geography.CUESTIONES CONTEMPORÁNEAS SOBRE LA ESCALARIDAD: FORMA, NATURALEZA Y ORGANIZACIÓN DE LAS ESCALAS GEOGRÁFICASResumen: El “problema de la escala” surge en Geografía en el momento en que se pone de manifiesto la necesidad de organizar las unidades espaciales identificables como una preocupación metodológica. Así, el tema se vuelve explícito y tratado en este ámbito académico principalmente a partir de la década de 1950. La difusión de ciertas referencias teórico-políticas en las investigaciones socio-espaciales ocidentales permitió que la cuestión escalar fuera, en los años siguientes, observada desde enfoques para los que dividir y organizar el espacio no era una cuestión meramente metodológica, sino también epistemológica y política ―y, por lo tanto, directamente vinculada a la práctica y a la acción social. Pero la proliferación de trabajos sobre escalas geográficas no se produjo de forma homogénea en los distintos ámbitos lingüísticos de la literatura especializada. En el caso anglófono, por ejemplo, eso ocurrió a partir de finales de los años ochenta. El objetivo de este artículo es caracterizar los principales ejes del debate sobre las escalas geográficas que tuvo lugar aproximadamente entre la última década del siglo XX y la primera del siglo XXI en las investigaciones realizadas en el entorno de la Geografía anglófona con el fin de aumentar la pluralidad de cuestiones que alimentan las reflexiones sobre la escala geográfica.Palabras clave: Escala geográfica; Historia del Pensamiento Geográfico; Geografía anglófona.

Solution for the degenerate scale for a rigid curve in antiplane elasticity by using a weakly singular integral equation

This paper provides a numerical solution for the degenerate scale for a rigid curve in antiplane elasticity. The degenerate scale problem for the rigid curve is formulated on the usage of the logarithmic potential. After assuming the displacement to be a vanishing value along the rigid curve, the boundary integral equation (BIE) is formulated. The problem can be first formulated in the degenerate scale. After making a coordinate transform, we can obtain the relevant BIE in the ordinary scale. Finally, a numerical solution is achieved. Several numerical examples are provided. In addition, the degenerate scale problem for the multiple rigid curves is also solved.

Class of Tests Based on Subsample Quantiles for Two-sample Scale Problem

A class of distribution-free tests based on U-statistics with its kernel being function of subsample quantiles is proposed for a two-sample scale problem. The proposed class of tests is a general class of tests that includes numerous members which explore information from the tails of the distributions and tests resistant to outliers. This class of tests includes many existing classes of tests as its subclasses. The distribution of the proposed class of tests is derived and its relevance is discussed. One of its members, which is resistant to outliers in -sample is investigated in detail.