scholarly journals Trade-offs between wood supply and caribou habitat in northwestern Ontario

Rangifer ◽  
1998 ◽  
Vol 18 (5) ◽  
pp. 149 ◽  
Author(s):  
Daniel McKenney ◽  
Bryan Nippers ◽  
Gerald Racey ◽  
Rob Davis
Keyword(s):  
Forest Management ◽  
Fire Disturbance ◽  
Management Problem ◽  
Spatial Problem ◽  
Wood Production ◽  
Wood Supply ◽  
Northwestern Ontario ◽  
Trade Offs ◽  
Wide Range ◽  
The Cost

Woodland caribou habitat management in northwestern Ontario is a complex spatial problem. The Strategic Forest Management Model (SFMM), a linear programming PC-based planning tool being developed in Ontario, was used to examine the impacts of alternative management strategies on caribou habitat. The management alternatives investigated included the cessation of timber management and maximising the present value of wood production without any explicit concern (in the model) for caribou. Three major findings are worth noting: 1) trying to maintain prime caribou habitat within active Forest Management Units will come at a cost to wood supply but the cost will depend on the absolute amount of area affected and the spatial configuration of that land in relation to mills. The cost of maintaining caribou habitat in one management unit at a level about 25 000 hectares is roughly $324 000 per year (about 3 cents for each Ontario resident). The imposition of an even-flow constraint on wood production is in fact potentially more costly; 2) Given the region is heavily dominated by spruce aged 90 years and over, forest succession and fire disturbance will likely cause large declines in prime caribou habitat in the near to medium term (20 to 40 years) even if no timber harvesting occurs; 3) The complexities of the trade-offs in this resource management problem highlight the limitations of any single modelling tool to satisfactorily address all issues. Planners need to take advantage of a wide range of analytical techniques to quantify the issues and formulate integrated policies.

Opportunities and costs of intensification and clustering of forest management activities

2008 ◽  
Vol 38 (4) ◽  
pp. 711-720 ◽  
Author(s):  
Anne-Hélène Mathey ◽  
Emina Krcmar ◽  
John Innes ◽  
Ilan Vertinsky
Keyword(s):  
Forest Management ◽  
Boreal Forest ◽  
Timber Harvesting ◽  
Conservation Areas ◽  
Intensive Forest Management ◽  
Trade Offs ◽  
Planning Approach ◽  
Increasing Demand ◽  
Canadian Boreal Forest ◽  
The Cost

The intensification of forest management in Canada has been advocated as a possible solution to the conundrum that increasing demand for conservation areas and increasing pressure for timber production have created. The benefits and disadvantages of intensive forest management in the context of the Canadian boreal forest are unclear and reaching conclusions about its general value from stand analyses may be difficult. In this study, a boreal forest in Ontario has been used to investigate the potential of intensive management to generate financial revenues and meet management constraints on volume flow and old-growth retention. Two aspects of intensive forest management are considered: intensive silviculture and concentrated harvest activities. The plans are generated with a decentralized planning approach based on cellular automata. The results for the case study show that increasing silviculture intensity can help fulfill high timber flow requirements under strict conservation requirements. This comes at the cost of reduced net revenues but from a smaller timber harvesting landbase. The main trade-offs found were those between harvest flow and financial benefits. Clustering both protected areas and harvest operations could help achieve the conservation and timber-related objectives simultaneously by improving the habitat value of conserved areas and decreasing the operational costs in harvested areas.

Heat-Affected Zone Hardness Limits for In-Service Welding

2008 ◽  
Author(s):  
William A. Bruce ◽  
Bradley C. Etheridge ◽  
Andrew Carman
Keyword(s):  
Heat Affected Zone ◽  
Evaluation Criteria ◽  
Department Of Transportation ◽  
Hydrogen Cracking ◽  
Trade Offs ◽  
Wide Range ◽  
The Us ◽  
The Cost ◽  
Hydrogen Level ◽  
Development And Validation

Welds made onto in-service pipelines are particularly susceptible to hydrogen cracking. During qualification of welding procedures, limits are often imposed on heat-affected zone hardness (e.g., 350 HV max.) as a way to avoid cracking. The hardness level below which hydrogen cracking does not occur is not a fixed value, but varies as a function of several parameters. The results of previous work resulted in the development of hardness evaluation criteria that can be used to quantify the trade-offs that can be made between HAZ hardness, hydrogen level, and the chemical composition of the materials being welded for welds made onto in-service pipelines. This paper describes a current project that is being sponsored in part by the US Department of Transportation – Pipeline and Hazardous Materials Safety Administration, which is focusing on the further development and validation of these criteria, particularly for modern microalloyed materials and material over a wide range of wall thicknesses. The use of these criteria will reduce the cost and increase the reliability of pipeline modifications and repairs.

scholarly journals Forest management for optimizing soil protection: a landscape-level approach

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Ana Raquel Rodrigues ◽  
Susete Marques ◽  
Brigite Botequim ◽  
Marco Marto ◽  
José G. Borges
Keyword(s):  
Forest Management ◽  
Soil Erosion ◽  
Planning Horizon ◽  
Programming Approach ◽  
Soil Protection ◽  
Planning Problem ◽  
Management Problem ◽  
Critical Periods ◽  
Trade Offs ◽  
Landscape Level

Abstract Background Soil erosion is still identified as the main cause of land degradation worldwide, threatening soil functions and driving several research and policy efforts to reverse it. Trees are commonly associated to some of the most successful land-use systems to achieve soil protection goals, but the extent to which forest ecosystems reduce erosion risks can largely depend on management decisions and associated silvicultural practices. Optimization tools can assist foresters in solving the complex planning problem they face, concerning the demand for different, and often conflicting, ecosystem services. A resource capability model (RCM), based on a linear programming approach, was built and solved for a forest landscape management problem in Northwest Portugal, over a 90-years planning horizon, divided in 10-years periods. Results Timber provision and soil erosion were found to be in trade-off. The management alternatives included in the model were proven to be sufficiently flexible to obtain the desired level of timber yield, both in volume and even distribution along the planning horizon, while ensuring lower levels of soil loss estimates (below 35 Mg∙ha− 1∙year− 1). However, under climate change conditions, compatible with an increasing greenhouse gases emission scenario, potential landscape soil erosion may be enhanced up to 46 Mg∙ha− 1∙year− 1 in critical periods. Conclusions Soil conservation concerns in landscape-level forest management planning can be addressed by LP-based optimization methods. Besides providing an optimal management solution at landscape level, this approach enables a comprehensive analysis of the RCM, possible trade-offs and potential changes towards uncertainties.

Mechanical trade-offs explain how performance increases without increasing cost in rattlesnake tailshaker muscle

2002 ◽  
Vol 205 (5) ◽  
pp. 667-675 ◽  
Author(s):  
Brad R. Moon ◽  
J. Johanna Hopp ◽  
Kevin E. Conley
Keyword(s):  
Lateral Displacement ◽  
Metabolic Cost ◽  
Muscle Twitch ◽  
Joint Force ◽  
Time Integral ◽  
Trade Offs ◽  
Vertebrate Muscle ◽  
Wide Range ◽  
Tension Time ◽  
The Cost

SUMMARYRattling by rattlesnakes is one of the fastest vertebrate movements and involves some of the highest contraction frequencies sustained by vertebrate muscle. Rattling requires higher accelerations at higher twitch frequencies, yet a previous study showed that the cost per twitch of rattling is independent of twitch frequency. We used force and video recordings over a range of temperatures to examine how western diamondback rattlesnakes (Crotalus atrox) achieve faster movements without increases in metabolic cost. The key findings are (i) that increasing muscle twitch tension trades off with decreasing twitch duration to keep the tension–time integral per twitch nearly constant over a wide range of temperatures and twitch frequencies and (ii) that decreasing lateral displacement of the rattle joint moderates the mechanical work and power required to shake the rattle at higher frequencies. These mechanical trade-offs between twitch tension and duration and between joint force and displacement explain how force, work and power increase without an increase in metabolic cost.

scholarly journals Sexual deception: Coevolution or inescapable exploitation?

2014 ◽  
Vol 60 (1) ◽  
pp. 52-61 ◽  
Author(s):  
Jussi Lehtonen ◽  
Michael R. Whitehead
Keyword(s):  
Relative Magnitude ◽  
Arms Race ◽  
Sexual Signals ◽  
Sexual Deception ◽  
Stable Strategy ◽  
Trade Offs ◽  
Wide Range ◽  
Mating Opportunities ◽  
The Cost ◽  
Coevolutionary Arms Race

Abstract Sexual deception involves the mimicry of another species’ sexual signals in order to exploit behavioural routines linked to those signals. Known sexually deceptive systems use visual, acoustic or olfactory mimicry to exploit insects for prédation, cleptoparasitism and pollination. It is predicted that where sexual deception inflicts a cost on the receiver, a coevolutìonary arms race could result in the evolution of discriminating receivers and increasingly refined mimicry. We constructed a conceptual model to understand the importance of trade-offs in the coevolution of sexually deceptive mimic and receiver. Four components examined were: the cost of mimicry, the cost to receiver for being fooled, the density of mimics and the relative magnitude of a mimicry-independent component of fitness. The model predicts that the exploitation of non-discriminating receivers by accurate signal mimicry will evolve as an evolutionary stable strategy under a wide range of the parameter space explored. This is due to the difficulty in minimising the costs of being fooled without incurring the cost of falsely rejecting real mating opportunities. In the model, the evolution of deception is impeded when mimicry imposes substantial costs for both sides of the arms race. Olfactory signals that are potentially cheap to produce are therefore likely to be more vulnerable to exploitation than expensive visual ornaments.

Forests for wood production and stress recovery: trade-offs in long-term forest management planning

2015 ◽  
Vol 134 (5) ◽  
pp. 755-767 ◽  
Author(s):  
Eva-Maria Nordström ◽  
Ann Dolling ◽  
Erik Skärbäck ◽  
Jonathan Stoltz ◽  
Patrik Grahn ◽  
...  
Keyword(s):  
Forest Management ◽  
Stress Recovery ◽  
Wood Production ◽  
Management Planning ◽  
Forest Management Planning ◽  
Trade Offs

IMPROVEMENT OF INNOVATIVE ACTIVITY OF THE ENTERPRISE

2017 ◽  
Author(s):  
Nataliya Stoyanets ◽  
◽  
Mathias Onuh Aboyi ◽  
Keyword(s):  
Value Chain ◽  
Net Present Value ◽  
Successful Implementation ◽  
Innovative Development ◽  
Technological Equipment ◽  
Alliance Partner ◽  
Innovation Potential ◽  
Wide Range ◽  
Technological Platform ◽  
The Cost

The article defines that for the successful implementation of an innovative project and the introduction of a new product into production it is necessary to use advanced technologies and modern software, which is an integral part of successful innovation by taking into account the life cycle of innovations. It is proposed to consider the general potential of the enterprise through its main components, namely: production and technological, scientific and technical, financial and economic, personnel and actual innovation potential. Base for the introduction of technological innovations LLC "ALLIANCE- PARTNER", which provides a wide range of support and consulting services, services in the employment market, tourism, insurance, translation and more. To form a model of innovative development of the enterprise, it is advisable to establish the following key aspects: the system of value creation through the model of cooperation with partners and suppliers; creating a value chain; technological platform; infrastructure, determine the cost of supply, the cost of activities for customers and for the enterprise as a whole. The system of factors of influence on formation of model of strategic innovative development of the enterprise is offered. The expediency of the cost of the complex of technological equipment, which is 6800.0 thousand UAH, is economically calculated. Given the fact that the company plans to receive funds under the program of socio-economic development of Sumy region, the evaluation of the effectiveness of the innovation project, the purchase of technological equipment, it is determined that the payback period of the project is 3 years 10 months. In terms of net present value (NPV), the project under study is profitable. The project profitability index (PI) meets the requirements for a positive decision on project implementation> 1.0. The internal rate of return of the project (IRR) also has a positive value of 22% because it exceeds the discount rate.

Glarner Waldwirtschaft im letzten Viertel des 20. Jahrhunderts | Glarner Forest Management in the last quarter of the 20th Century

2002 ◽  
Vol 153 (7) ◽  
pp. 249-250
Author(s):  
Fritz Marti
Keyword(s):  
Forest Management ◽  
20Th Century ◽  
Logical Consequence ◽  
Mountain Forest ◽  
Wood Production ◽  
Looking Back

Looking back on the last quarter of the 20th century, we see that the most striking changes in forest management have come about following large and frequent catastrophes. Management– concerned solely with wood production in former times – is oriented more towards retaining stability of the stands nowadays. In addition, the aspect of tending and improving the environment continues to gain ground. The growing gap between expenditure and profit is particularly acute in Glarner mountain forest areas. The extension of promotional silvicultural measures, which widely determines today's management, is to be seen as a logical consequence.

scholarly journals New general mixed-integer linear programming model for mobile workforce management

2021 ◽  
Author(s):  
András Éles ◽  
István Heckl ◽  
Heriberto Cabezas
Keyword(s):  
Programming Model ◽  
Time Windows ◽  
Mutual Exclusion ◽  
Parallel Execution ◽  
Mixed Integer ◽  
Management Problem ◽  
Routing Problem ◽  
Workforce Management ◽  
Computational Performance ◽  
Wide Range

AbstractA mathematical model is introduced to solve a mobile workforce management problem. In such a problem there are a number of tasks to be executed at different locations by various teams. For example, when an electricity utility company has to deal with planned system upgrades and damages caused by storms. The aim is to determine the schedule of the teams in such a way that the overall cost is minimal. The mobile workforce management problem involves scheduling. The following questions should be answered: when to perform a task, how to route vehicles—the vehicle routing problem—and the order the sites should be visited and by which teams. These problems are already complex in themselves. This paper proposes an integrated mathematical programming model formulation, which, by the assignment of its binary variables, can be easily included in heuristic algorithmic frameworks. In the problem specification, a wide range of parameters can be set. This includes absolute and expected time windows for tasks, packing and unpacking in case of team movement, resource utilization, relations between tasks such as precedence, mutual exclusion or parallel execution, and team-dependent travelling and execution times and costs. To make the model able to solve larger problems, an algorithmic framework is also implemented which can be used to find heuristic solutions in acceptable time. This latter solution method can be used as an alternative. Computational performance is examined through a series of test cases in which the most important factors are scaled.

scholarly journals Ring-Forming Polymerization toward Perfluorocyclobutyl and Ortho-Diynylarene-Derived Materials: From Synthesis to Practical Applications

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1486
Author(s):  
Eugene B. Caldona ◽  
Ernesto I. Borrego ◽  
Ketki E. Shelar ◽  
Karl M. Mukeba ◽  
Dennis W. Smith
Keyword(s):  
Chemical Resistance ◽  
Structural Features ◽  
Review Article ◽  
Aryl Ether ◽  
Aromatic Rings ◽  
Practical Applications ◽  
Repeat Units ◽  
Wide Range ◽  
Synthetic Routes ◽  
The Cost

Many desirable characteristics of polymers arise from the method of polymerization and structural features of their repeat units, which typically are responsible for the polymer’s performance at the cost of processability. While linear alternatives are popular, polymers composed of cyclic repeat units across their backbones have generally been shown to exhibit higher optical transparency, lower water absorption, and higher glass transition temperatures. These specifically include polymers built with either substituted alicyclic structures or aromatic rings, or both. In this review article, we highlight two useful ring-forming polymer groups, perfluorocyclobutyl (PFCB) aryl ether polymers and ortho-diynylarene- (ODA) based thermosets, both demonstrating outstanding thermal stability, chemical resistance, mechanical integrity, and improved processability. Different synthetic routes (with emphasis on ring-forming polymerization) and properties for these polymers are discussed, followed by their relevant applications in a wide range of aspects.

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