Maine Tidal Power Initiative: Environmental Impact Protocols for Tidal Power

As a result of ongoing climate change, the pressure for the development of new sources of renewable energy has increased. It is extremely likely that climate change is caused by anthropogenic activities. Thus even if dramatic gains are made in energy efficiency; the addition of novel renewable energy sources is critical to reducing fossil fuel emissions. Even current goals for a reduction in the growth of greenhouse gas emissions mean that all possible low-carbon or non-carbon emitting energy sources be considered. In the marine environment, energy in tidal currents, waves, and thermal structure may be extracted to produce electricity. These energy sources are a critical element in the overall renewable portfolio since, unlike wind and solar energy, both marine thermal and tidal energy are reliable additions to the overall electrical grid. In the case of tidal energy, the contribution of periodic but reliable sources of renewable energy becomes increasingly critical as wind and solar penetration in the grid increase. In a high renewable energy penetration grid, a resource like tidal energy does not provide the same base load capacity as, for example, a nuclear power plant. However, tidal energy can have the effect of reducing the size of either storage or peaking capacity that is required for grid stability by providing power for recovery of dispatchable loads. However, as an immature technology, significant questions remain regarding basic questions like the scale of the potential resource, the impact on sediment transport, the effects on fish populations and communities, and the ability to design a system which is acceptable by the people in the associated communities. The objectives of the funded project were to examine tidal power development in Maine from all perspectives: engineering, resource assessment, biological effects, and social dimensions. Resource and environmental research focused on data collection for the Cobscook Bay/Western Passage, possibly the most viable commercial tidal energy site in the US, tidal power sites along with initial evaluation of the suitability of the approach for at least two other tidal development sites in Maine. Concomitantly, alternative energy research is used as a basis of education for a number of graduate and undergraduate students at the University of Maine and Maine Maritime Academy. The Maine Tidal Power Initiative has developed resource and environmental assessment protocols in conjunction with the deployment of a specific marine hydrokinetic device. The protocols are transferrable throughout Maine and the US to evaluate tidal energy resources and better understand the potential impact of this development on the environment. Again, site-specific social science and environmental research focused on the Cobscook Bay/Western Passage area near Eastport Maine. The protocols and methods developed at these sites have also been used to perform initial scoping reviews of locations in Castine Harbor and Wiscasset, Maine that represent a more modest and more typical small scale energy resource. Specific barrier issues which have been addressed for the industry are technologies and protocols for measuring and modeling tidal flows, responses of fishes to those flows, and people interacting in these environments. Measuring tidal flows is critical to the key economic driver for this industry, the size of the potential resource. The second barrier issue is the need for methods for measuring the impact of marine hydrokinetic (MHK) devices on fish. Acoustic methods have been used with ground truth validation from trawls. The protocols developed in this project have already had a significant impact on the approach that has been taken at other sites. Finally the assessment of the human community response to these technologies and impact on community cohesion and participation is perhaps the largest single barrier to the acceptance of the projects. This work also has the potential to be replicated at other sites, although in both the case of the environmental effects and the social response to these projects, details of the species impacted and the economic and social environment are the ultimate determinants of impact and acceptance. The technology focus for most of this work has been the cross-flow turbine developed by Ocean Renewable Power Company. Testing in the University of Maine tow tank has allowed a large design space to be explored for the optimization of the commercial turbine design. The design code developed for the project was validated using this data set. Both the design code and the data will be placed in a public repository. The most important outcome of the turbine design portion of the work is some general design parameters that can be used to assist in the site assessment and for benchmarking of proprietary designs. The design as well as the data is available for resource assessment and design comparisons. The appeal of this turbine design is that the potential exists for a low solidity turbine with lower tip speed ratios, which will have good performance. The low solidity and tip speed ratio is likely to reduce the risk of fish impacts and thus reduce environmental impact and community resistance to these technologies. The need for low carbon energy sources is undeniable. Resistance to large-scale renewable energy development also continues to increase. The overall approach to this project, where the design of the system considers environmental impacts and social acceptance from the initial engineering design stages and continues with an adaptive management scheme, is the only option for addressing energy needs at the scale required

Q(sqrt(-3))-Integral Points on a Mordell Curve

We use an extension of quadratic Chabauty to number fields,recently developed by the author with Balakrishnan, Besser and M ̈uller,combined with a sieving technique, to determine the integral points overQ(√−3) on the Mordell curve y2 = x3 − 4

Numerical Modeling in Civil and Mining Geotechnical Engineering

This Special Issue (SI) collects fourteen articles published by leading scholars of numerical modeling in civil and mining geotechnical engineering. There is a good balance in the number of published articles, with seven in civil engineering and seven in mining engineering. The software used in the numerical modeling of these article varies from numerical codes based on continuum mechanics to those based on distinct element methods or mesh-free methods. The studied materials vary from rock, soil, and backfill to tailings. The investigations vary from mechanical behavior to hydraulic and thermal responses of infrastructures varying from pile foundations to tailings dams and underground openings. The SI thus collected a diversity of articles, reflecting the state-of-the-art of numerical modeling applied in civil and mining geotechnical engineering

An Investigation on Benefit-Cost Analysis of Greenhouse Structures in Antalya

Significant population increase across the world, loss of cultivable land and increasing demand for food put pressure on agriculture. To meet the demand, greenhouses are built, which are, light structures with transparent cladding material in order to provide controlled microclimatic environment proper for plant production. Conceptually, greenhouses are similar with manufacturing buildings where a controlled environment for manufacturing and production have been provided and proper spaces for standardized production processes have been enabled. Parallel with the trends in the world, particularly in southern regions, greenhouse structures have been increasingly constructed and operated in Turkey. A significant number of greenhouses are located at Antalya. The satellite images demonstrated that for over last three decades, there has been a continuous invasion of greenhouses on all cultivable land. There are various researches and attempts for the improvement of greenhouse design and for increasing food production by decreasing required energy consumption. However, the majority of greenhouses in Turkey are very rudimentary structures where capital required for investment is low, but maintenance requirements are high when compared with new generation greenhouse structures. In this research paper, life-long capital requirements for construction and operation of greenhouse buildings in Antalya has been investigated by using benefit-cost analysis study

Knowledge Capturing in Design Briefing Process for Requirement Elicitation and Validation

Knowledge capturing and reusing are major processes of knowledge management that deal with the elicitation of valuable knowledge via some techniques and methods for use in actual and further studies, projects, services, or products. The construction industry, as well, adopts and uses some of these concepts to improve various construction processes and stages. From pre-design to building delivery knowledge management principles and briefing frameworks have been implemented across project stakeholders: client, design teams, construction teams, consultants, and facility management teams. At pre-design and design stages, understanding the client’s needs and users’ knowledge are crucial for identifying and articulating the expected requirements and objectives. Due to underperforming results and missed goals and objectives, many projects finish with highly dissatisfied clients and loss of contracts for some organizations. Knowledge capturing has beneficial effects via its principles and methods on requirement elicitation and validation at the briefing stage between user, client and designer. This paper presents the importance and usage of knowledge capturing and reusing in briefing process at pre-design and design stages especially the involvement of client and user, and explores the techniques and technologies that are usable in briefing process for requirement elicitation

Noncommutative Biology: Sequential Regulation of Complex Networks and Connected Matter

During animal development from zygote to adult, a limited set of regulatory molecules are autonomously deployed in the service of tissue-specific gene expression (reviewed in chapter 1). Inherent in the process is the tension that single cells sample heterogeneous expression states while robustly maintaining a collective final outcome. This thesis addresses theoretical issues that help resolve the paradox that one cell simultaneously contains the fate information of many. Previous models of development have likened cell fate to minima on a smooth potential energy surface. Such static pictures can be misleading because they suggest the egg knows the path it will take to the adult before it divides even once. Recognition that the potential analogy is an oversimplification has led others to propose that the surface is actually nonsmooth. Chapter 2 reviews the theoretical basis for smooth potentials and resolves these problems by appealing to the tangent space of gene expression. It is then shown that if the potential difference is sufficient to characterize the difference between egg and adult, then the tangent space controls on gene expression are one-dimensional. Furthermore, a shortcoming of models ignoring the connectivity and common origin of dividing cells is that they erect artificial barriers between alternative fates. A fundamentally different picture is sketched wherein the difference between egg and adult is schematized as the shape of the locus of equipotential fates accessible at the same point in time. The conjugacy of space and time is invoked to explain how the requirement that each fate be on a line of equipotential is the same as requiring that each alternative fate move the same distance down the surface at each step. The developmental trajectory is deterministic but not known in advance because it needs to be ascertained at each step which way cells "turn" in order to maintain their equipotential relationship. Chapters 3 and 4 refine this sequential model of collective development with specific examples. A simple solution to the problem of cell-type specific gene expression is combinatorial binding of transcription factors at promoters. It is shown in chapter 3 that such models result in substantial information bottlenecks, because all cell fate information is concentrated at the start. We explore a novel, noncommutative model of gene regulation&#8212;known as sequential logic&#8212;that spreads the information out over time. It is shown using time sequences of noncommutative controllers that targets which otherwise would have been activated together can be regulated independently. We derive scaling laws for two noncommutative models of regulation, motivated by phosphorylation/neural networks and chromosome folding, respectively, and show that they scale super-exponentially in the number of regulators. It is also shown that specificity in control is robust to loss of a regulator. Consequently, sequential logic overcomes the information bottleneck in complex problems and enables novel solutions through roundabout strategies. The theoretical results are connected to real biological networks demonstrating specificity in the context of promiscuity. Noncommutative sequential logic has improved storage capacity, but it does not specify who or what supplies the sequences of input that determine cell fate. Chapter 4 offers a solution by way of the seemingly unrelated problem of looping in twisted strings. Cells and strings obey a set of common space-time constraints, ultimately due to the conservation of energy. It is argued that the most parsimonious allocation of energy from the straight to strained string is the one in which each segment sees the same share of the total. Planar looping is shown to be a consequence of the parsimony principle and the Euler-Poincar&#233; equations for rotational motion in the presence an applied torque. We then solve the problem for the looping of a twisted string; with two strains, the Euler-Poincar&#233; predict a different answer than the classical Frenet-Serret equations. Using the results of chapter 2, it is concluded that the Frenet-Serret curvatures assigned ahead of time are not guaranteed to generate space curves that conserve energy: the predicted string has localized strains the Euler-Poincar&#233; solution lacks. Rotational dynamics of strings are connected to developing organisms by postulating conserved RNA polymerase as an analog of angular momentum, and transcriptional activity as energy. Alternative fates along a one-dimensional "string" of dividing cells are possible by finding the RNAP distribution that conserves transcriptional activity along a curve of constant developmental potential. Consequently, each alternative fate samples a different sequence of changes to the distribution as it follows a local gradient downhill from high to low developmental potential over time. In conclusion, regulation in the tangent space of gene expression resolves the paradox that development has a unique solution specified in the DNA of the egg which cannot be determined with certainty until completion of the adult. Noncommutative sequential logic generates complexity that cannot be realized at the start, while interdependent cells (and strings) require time to ensure that each fate is at the same potential difference from a common ancestor. This fundamental reimagining of the Waddington framework can be tested using new multiplexed mRNA imaging technologies that preserve the spatial context of cells in developing tissue.</p

Recent Development of Hybrid Renewable Energy Systems

Abstract: The use of renewable energies continues to increase. However, the energy obtained from renewable resources is variable over time. The amount of energy produced from the renewable energy sources (RES) over time depends on the meteorological conditions of the region chosen, the season, the relief, etc. So, variable power and nonguaranteed energy produced by renewable sources implies intermittence of the grid. The key lies in supply sources integrated to a hybrid system (HS)