Optimal Burn-in Time and Imperfect Maintenance Strategy for a Warranted Product with Bathtub Shaped Failure Rate

‘Burn-in/preventive maintenance’ programme is an efficient approach used to minimise the warranty servicing cost of a product with bathtub shaped failure rate. Burn-in is a widely used method to improve the quality of product during its ‘infant mortality’ period and preventive maintenance is a scheduled necessary activity carried out during its ‘wear-out’ period. In this paper, an optimisation model is developed to determine the optimal burn-in time and optimal imperfect preventive maintenance strategy that minimises the total mean servicing cost of a warranted product with an age-dependent repair cost. We provide a numerical study to illustrate our results

Market Segmentation vs. Subsidization: Clean Energy Credits and the Commerce Clause\u27s Economic Wisdom

The dormant Commerce Clause has long been a thorn in the side of state policymakers. The latest battleground for the clash between federal courts and state legislatures is energy policy. In the absence of a decisive federal policy response to climate change, nearly thirty states have created a new type of securities—clean energy credits—to promote lowcarbon renewable and nuclear power. As more and more of these programs come under attack for alleged violations of the dormant Commerce Clause, this Article explores the constitutional constraints on clean energy credit policies. Careful analysis of recent and ongoing litigation reveals the need for better differentiation between constitutionally questionable market segmentation and constitutionally sound subsidization policies—in clean energy policy and beyond. Many observers view the dormant Commerce Clause doctrine as a major threat to state-led efforts to combat climate change. Pushing back against widespread scholarly skepticism and recent precedent, this Article makes the case that state policymakers can use clean energy credits to simultaneously promote global environmental and local economic causes without running afoul of the dormant Commerce Clause. Critics and courts alike fail to recognize that not all energy credit programs are created equal. When states use energy credits as compliance instruments for their renewable portfolio standards—requirements that electric utilities source a percentage of their electricity sales from solar, wind, and other renewables—they partition power markets into renewable and nonrenewable segments. Such segmentation policies cannot follow state boundaries or other geographically defined lines without violating the dormant Commerce Clause. A few pioneering states have begun to use energy credits as a vehicle for subsidies that operate independently of sourcing requirements. Unlike their market segmentation counterparts, these subsidization policies raise no concerns under the dormant Commerce Clause even when subsidies are available only to in-state firms. The Commerce Clause’s “preference” for subsidization over segmentation policies may seem counterintuitive. Both have, after all, the potential to disrupt interstate commerce and competition. Yet, two centuries of dormant Commerce Clause jurisprudence reflect a simple economic truth: segmentation prevents competition altogether, while subsidization can have a pro-competitive effect, such as when used to correct for carbon externalities and other market failures

Market Segmentation vs. Subsidization: Clean Energy Credits and the Commerce Clause\u27s Economic Wisdom

The dormant Commerce Clause has long been a thorn in the side of state policymakers. The latest battleground for the clash between federal courts and state legislatures is energy policy. In the absence of a decisive federal policy response to climate change, nearly thirty states have created a new type of securities—clean energy credits—to promote low-carbon renewable and nuclear power. As more and more of these programs come under attack for alleged violations of the dormant Commerce Clause, this Article explores the constitutional constraints on clean energy credit policies. Careful analysis of recent and ongoing litigation reveals the need for better differentiation between constitutionally questionable market segmentation and constitutionally sound subsidization policies—in clean energy policy and beyond. Many observers view the dormant Commerce Clause doctrine as a major threat to state-led efforts to combat climate change. Pushing back against widespread scholarly skepticism and recent precedent, this Article makes the case that state policymakers can use clean energy credits to simultaneously promote global environmental and local economic causes without running afoul of the dormant Commerce Clause. Critics and courts alike fail to recognize that not all energy credit programs are created equal. When states use energy credits as compliance instruments for their renewable portfolio standards—requirements that electric utilities source a percentage of their electricity sales from solar, wind, and other renewables—they partition power markets into renewable and nonrenewable segments. Such segmentation policies cannot follow state boundaries or other geographically defined lines without violating the dormant Commerce Clause. A few pioneering states have begun to use energy credits as a vehicle for subsidies that operate independently of sourcing requirements. Unlike their market segmentation counterparts, these subsidization policies raise no concerns under the dormant Commerce Clause even when subsidies are available only to in-state firms. The Commerce Clause’s “preference” for subsidization over segmentation policies may seem counterintuitive. Both have, after all, the potential to disrupt interstate commerce and competition. Yet, two centuries of dormant Commerce Clause jurisprudence reflect a simple economic truth: segmentation prevents competition altogether, while subsidization can have a pro-competitive effect, such as when used to correct for carbon externalities and other market failures

First year sprouting and growth dynamics of northern red oak, yellow-poplar, red maple, and sweet birch on a mesic site following a release burn during a shelterwood-burn sequence

Oak regeneration challenges are a widespread issue across the mixed oak and mixed mesophytic forests of the eastern United States. Following disturbance on many mesic and sub-mesic sites oaks are being replaced by faster growing or shade tolerant species. There are many contributing factors, but one thought to have the strongest influence is attributed to the effects of 20th century fire suppression. For millennia fire was an integral part of oak dominated ecosystems and is thought to have contributed to and perpetuated oak\u27s importance in these forests. During the 20th century the frequency and spatial scale of fire was severely reduced in most eastern forests. In the absence of fire, oaks are unable to benefit from their unique developmental and physiological traits superiorly adapted to a periodic fire regime and maintain their dominance. The fire adapted traits important at different life stages of oaks include modest growing site requirements, hypogeal germination, early growth strategy of root development over of shoot development, ability to repeatedly sprout following dieback or topkill, development of thick fire resistant bark, and ability to compartmentalize wounds. As the ecological effects of fire suppression have materialized and compounded over time, prescribed fire has emerged as a silvicultural tool to modify competitive dynamics in an effort to maintain or restore oak communities. Although there are a rapidly increasing number of prescribed fire studies, replications are still necessary with different combinations of variables to determine the conditions that will produce successful results with greater certainty. This goal of this study was to examine the competitive relationship between oak seedlings and three of its competitors, develop first year survival probability models, and assess post-fire sprout growth dynamics. First year data show that oak survived at a higher rate than red maple, sweet birch, and yellow-poplar, and the differences were more apparent at smaller sizes. Probability of survival models as a function of height are superior to survival models as a function of diameter for red maple, sweet birch, and yellow-poplar. Oak survival was so high a meaningful survival probability model could not be developed

International Economic Agreements and the Constitution

International agreements, such as the General Agreement on Tariffs and Trade (GATT) and the North American Free Trade Agreement (NAFTA), generally aim to facilitate the free flow of goods and services among nations.1 The U.S. Supreme Court has developed a jurisprudence similarly aiming to facilitate the free flow of goods and services among the several states. That jurisprudence has developed from litigation challenging the constitutionality of state actions on the basis of the Commerce and Supremacy Clauses of the Constitution (art. I, § 8, cl. 3, and art. VI, cl. 2). In some subject areas, Commerce Clause decisions closely align with international agreements. In other areas, either or both fall short of achieving economic integration.

Energy Policy, Extraterritoriality, the Dormant Commerce Clause

This Article will focus specifically on potential challenges to state energy policy based on the “extraterritoriality doctrine” of the dormant Commerce Clause. In doing so, it considers two recent lawsuits involving dormant Commerce Clause challenges to state energy policy. The first is the lawsuit against the State of California over its Low Carbon Fuels Standard (LCFS) program on grounds that it discriminates against Midwest ethanol producers in favor of California ethanol producers and regulates extraterritorially in violation of the dormant Commerce Clause. The second is the lawsuit by the State of North Dakota, the North Dakota lignite coal industry, and regional electric cooperatives against the State of Minnesota over provisions of its Next Generation Energy Act (NGEA). The NGEA prohibits new coal-fired electricity generation in the state and prohibits imports of new coal-fired generation from outside the state without accompanying CO2 offsets. In that case the plaintiffs allege, among other things, that the law discriminates against out-of-state coal interests and regulates extraterritorially in violation of the dormant Commerce Clause. This Article will discuss both of the cases in detail to highlight the potential challenges associated with state efforts to use energy policy to address climate change, and to suggest how to place those cases in today’s dormant Commerce Clause jurisprudence

Restoring the Longleaf Pine (\u3ci\u3ePinus palustris\u3c/i\u3e) Forests Using Pineywoods Cattle Grazing in Conjunction with Prescribed Burning

The longleaf pine (Pinus palustris) is major forest constituent of the Southern Coastal Plains of the United States. Ecologically, a virgin longleaf pine forests supports increased species richness. Since the 1800s, longleaf pine forests have been exploited as a massive source of commercial products (e.g., lumber, pulp, and naval stores). A decrease in species richness has been recorded following this vast decrease in longleaf pine presence. Rebuilding the longleaf pine ecosystem is essential for restoring species richness and maintaining the ecological health of many Costal Plains habitats. Presently, the most popular restoration and management method utilized is prescribed burning. Prescribed burnings allow small, controlled fires to safely mimic the effects of naturally occurring wildfires. More recently, interest in the use of prescribed burning in the longleaf pine forests has increased because of the potential applications for reducing forests floor fuel loads and increasing species richness. A lesser-known practice of restoration is the implementation of grazing by cattle populations. Previous studies have shown an increase in species richness and a decrease in litter-cover when sites were introduced to grazing. Little research studying the interactions between grazing and prescribed burning has been conducted, however. We studied the effects of prescribed burns and grazing at the Longleaf Preserve, located in the Lake Thoreau Environmental Research Center (LTEC) in Hattiesburg, Mississippi. A series of treatment sites were constructed to determine the influence of grazing by pineywoods cattle and prescribed burns on plant diversity and physiognomy of the forest floor. These sites were subjected to four different treatments in an attempt to replicate current environmental conditions. v Fuel loads (i.e., available material for burning) were assessed by collecting data on fine and course litter (e.g., fallen leaves, twigs, branches), as well as, understory plant species richness. The litter samples were collected, dried, and placed on a scale to determine weight. The plant species within each sample were then separated based on morphology. The preliminary results indicate that combining pineywoods cattle grazing with a prescribed burning regimen is an effective means of decreasing leaf-litter cover and increasing species richness on the forest floor