To send content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about sending content to .
To send content items to your Kindle, first ensure firstname.lastname@example.org
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about sending to your Kindle.
Note you can select to send to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Wire-shaped supercapacitors (WSSCs) hold great promise in portable and wearable electronics. Herein, a novel kind of high-performance coaxial WSSCs has been demonstrated and realized by scrolling porous carbon dodecahedrons/Al foil film electrode on vertical FeOOH nanosheets wrapping carbon fiber tows (FeOOH NSs/CFTs) yarn electrode. Remarkably, ionogel is utilized as solid-state electrolyte and exhibits a high thermal/electrochemical stability, which effectively ensures the great reliability and high operating voltage of coaxial WSSCs. Benefiting from the intriguing configuration, the coaxial WSSCs with superior flexibility act as efficient energy storage devices and exhibit low resistance, high volumetric energy density (3.2 mW h/cm3), and strong durability (82% after 10,000 cycles). Importantly, the coaxial WSSCs can be effectively recharged by harvesting sustainable wind source and repeatedly supply power to the lamp without a decline of electrochemical performance. Considering the facile fabrication technology with an outstanding performance, this work has paved the way for the integration of sustainable energy harvesting and wearable energy storage units.
The transportation sector is the largest contributor to greenhouse gas emissions in the United States. One method being used to reduce greenhouse emissions related to the transportation sector is improving vehicle fuel efficiency through mass reduction. Reducing the mass of on-highway passenger vehicles by 10% can result in vehicle fuel economy improvements of as much as 6–8% if the powertrain is downsized to maintain equivalent performance. Some of the materials being investigated and implemented to reduce passenger vehicle mass include advanced high-strength steel, aluminum, magnesium, and polymer composites. Additionally, multimaterial structures that allow for optimal combinations of lightweight materials to achieve maximum weight reduction with lowest cost and best structural performance have recently become of particular interest. However, assembling multimaterial structures can be challenging due to differences in melting temperature and coefficient of thermal expansion of different materials, as well as formation of intermetallic compounds and galvanic corrosion potential. Joining technologies for lightweight multimaterial structures must address these challenges to be successful. This article highlights advances made in five different joining techniques: nondestructive evaluation of resistance spot-welded aluminum to steel, modeling of structural adhesives, temperature control of friction stir welds, ultrasonic welding of magnesium, and vapor foil actuation welding.
This article offers a conceptual understanding and easily applicable guidelines for sustainable urban infrastructure design by focusing on the demand for and supply of the services provided by seven urban infrastructure systems.
For more than 10,000 years, cities have evolved continuously, often shaped by the challenges they had to face. Similarly, we can imagine that cities will have to evolve again in the future to address their current challenges. Specifically, urban infrastructure will need to adapt and use less energy and fewer resources while becoming more resilient. In this article, starting with a definition of sustainability, two urban infrastructure sustainability principles (SP) are introduced: (i) controlling the demand and (ii) increasing the supply within reason, which are then applied to seven urban infrastructure systems: water, electricity, district heating and cooling and natural gas, telecommunications, transport, solid waste, and buildings. From these principles, a four-step urban infrastructure design (UID) process is compiled that can be applied to any infrastructure project: (i) controlling the demand to reduce the need for new infrastructure, (ii) integrating a needed service within the current infrastructure, (iii) making new infrastructure multifunctional to provide for other infrastructure systems, and (iv) designing for specific interdependencies and decentralizing infrastructure if possible. Overall, by first recognizing that urban infrastructure systems are inherently integrated and interdependent, this article offers several strategies and guidelines to help design sustainable urban infrastructure systems.
This paper compares the U.S. Environmental Protection Agency’s (EPA) ex ante compliance cost estimates for the 2004 Automobile and Light-Duty Truck Surface Coating National Emission Standards for Hazardous Air Pollutants to ex post evidence on the actual costs of compliance based on ex post cost data gathered from a subset of the industry via pilot survey and follow-up interviews. Unlike many prior retrospective studies on the cost of regulatory compliance, we use this newly gathered information to identify the key drivers of any differences between the ex ante and ex post estimates. We find that the U.S. EPA overestimated the cost of compliance for the plants in our sample and that overestimation was driven primarily by differences in the method of compliance rather than differences in the per-unit cost associated with a given compliance approach. In particular, the U.S. EPA expected facilities to install pollution abatement control technologies in their paint shops to reduce emissions of hazardous air pollutants, but instead these plants complied by reformulating coatings.
Valuing changes in time use is often a critical element of economic analyses of development projects. In this paper we review the literature on the monetary value of time in low- and middle-income countries and find support for a commonly used benchmark of 50% of after-tax wages for time changes in activities in the informal sector, such as collecting water or traveling to health clinics. We offer recommendations to analysts who are conducting benefit-cost analyses in these settings about what methods they can use to estimate the value of time. These include a benefits transfer approach and also a relatively simple stated preference approach that might be deployed in a specific context if the project recommendation is sensitive to the assumption of the value of time or if the distribution of the benefits of time savings is especially important.
Although federal regulation of vehicle fuel economy is often seen as environmental policy, over 70% of the estimated benefits of the 2017–2025 federal standards are savings in consumer expenditures on gasoline. Rational-choice economists question the counting of these benefits since studies show that the fuel efficiency of a car is reflected in its price at sale and resale. We contribute to this debate by exploring why most consumers in the United States do not purchase a proven fuel-saving innovation: the hybrid-electric vehicle (HEV). A database of 110 vehicle pairs is assembled where a consumer can choose a hybrid or gasoline version of virtually the same vehicle. Few choose the HEV. A total cost of ownership model is used to estimate payback periods for the price premiums associated with the HEV choice. In a majority of cases, a rational-choice explanation is sufficient to understand consumer disinterest in the HEV. However, in a significant minority of cases, a rational-choice explanation is not readily apparent, even when non-pecuniary attributes (e.g., performance and cargo space) are considered. Future research should examine, from a behavioral economics perspective, why consumers do not choose HEVs when pricing and payback periods appear to be favorable.
General Motors (GM) became the world's dominant automaker in the 1920s and 1930s thanks in part to a dynamic, centralized public relations operation. The intended audience of this marketing included GM's own overseas employees. As the company opened new plants in foreign countries, it used media such as General Motors World, an employee newspaper, to communicate that it understood the needs of different foreign consumers and to advocate against protectionist economic policies that hindered its ability to sell cars. The messages of General Motors World shaped global perceptions of GM's corporate structure and brand, and were a core element of the automaker's overseas activity.
We present some recently acquired results corresponding to the nature of the electron transport that occurs within bulk alloys of zinc-magnesium-oxide. These results are obtained using three-valley ensemble semi-classical Monte Carlo electron transport simulations. The impact that the magnesium content plays in shaping the form of the electron transport related characteristics associated with this alloy system is explored. Both steady-state and transient electron transport results are examined. The device implications of these results are then commented upon.
Aircraft that take off and land verticallywith rotors or horizontal propellers like drones use more energy than conventional aircraft whose lift is provided by wings. Drones with propellers are less efficient than helicopters with large rotors. The poor energy density of batteries compared to hydrocarbon fuels limits the range and endurance of the electrically powered aircraft. Although the ratio of the mass of payload and fuel (or battery) to the total aircraft mass for the proposed Amazon drone is not that different from the same ratio for a Boeing 747, the range and time in the air is very much less. In principle, a conventional aircraft powered by photovoltaic panels covering a wing with a span of 6 m could match the performance of the proposed Amazon drone.
Amazon has proposed delivering packages by an electrically powered drone capable of vertical take off and landing. By comparison with helicopters, the energy needed to move a 2.5 kg package is estimated to be more than 130 times the energy used in delivering the same package in a small delivery truck. By comparison, a conventional airplane with the same mass could, in principle, be powered by photovoltaic panels, covering the wings, and it would use an energy equivalent to about 3 times the energy used by a small delivery truck. Based on the performance of existing small helicopters, the analysis shows that an electrically powered air taxi would only be able to make journeys of 10 min or less. Vertical take-off and landing add to energy requirements, and drones using a large number of propellers are less efficient than helicopters. The major limitation, not surprisingly, is the poor energy density of batteries compared to liquid hydrocarbon fuels.
Although benefit-cost analysis (BCA) can be traced back to European thinkers, its first practical applications were in the United States. Recent years have witnessed a growing demand for economic appraisals of policies in different sectors in Europe, but the implementation rate is still low compared to that in the United States. This article introduces a symposium that includes four articles that present current examples of how BCA is being applied in different sectors and in different institutional settings in Europe. They deal with environmental valuation in the United Kingdom, economic analysis for investment in Sweden’s transport sector, economic versus financial returns in European Union investment project appraisal, and BCA in EU chemicals legislation. The goal is to stimulate continuing discussion on the implementation of BCA, not only in Europe but also worldwide.
Agricultural industrialisation and globalisation have steadily increased the transportation of food across the world. In efforts to promote sustainability and self-sufficiency, organic milk producers in Sweden are required to produce a higher level of cattle feed on-farm in the hope that increased self-sufficiency will reduce reliance on external inputs and reduce transport-related greenhouse gas emissions. Using data collected from 20 conventional and 20 organic milk producers in Sweden this paper aims to assess the global warming impact of farmyard vehicles and the transportation of feed produced ‘off-farm’ in order to compare the impact of vehicle-related emissions from the different production methods. The findings show organic and conventional production methods have different vehicle-related emission outputs that vary according to a reliance on either road transportation or increased farmyard machinery use. Mechanical weeding is more fuel demanding than conventional agrichemical sprayers. However, artificial fertilising is one of the highest farmyard vehicle-related emitters. The general findings show organic milk production emits higher levels of farm vehicle-related emissions that fail to be offset by reduced emissions occurring from international transport emissions. This paper does not propose to cover a comprehensive supply chain carbon footprint for milk production or attempt to determine which method of production has the largest climatic impact. However, it does demonstrate that Sweden's legal requirements for organic producers to produce more feed on-farm to reduce transport emissions have brought emissions back within Sweden's greenhouse gas inventory and raises questions around the effectiveness of policies to reduce vehicle-related emissions. Further research is needed into the effectiveness of climate change mitigation on food production policies, in particular looking at various trade-offs that affects the entire food supply chain.
Regulatory impact analyses (RIAs) weigh the benefits of regulations against the burdens they impose and are invaluable tools for informing decision makers. We offer 10 tips for nonspecialist policymakers and interested stakeholders who will be reading RIAs as consumers.
1.Core problem: Determine whether the RIA identifies the core problem (compelling public need) the regulation is intended to address.
2.Alternatives: Look for an objective, policy-neutral evaluation of the relative merits of reasonable alternatives.
3.Baseline: Check whether the RIA presents a reasonable “counterfactual” against which benefits and costs are measured.
4.Increments: Evaluate whether totals and averages obscure relevant distinctions and trade-offs.
5.Uncertainty: Recognize that all estimates involve uncertainty, and ask what effect key assumptions, data, and models have on those estimates.
6.Transparency: Look for transparency and objectivity of analytical inputs.
7.Benefits: Examine how projected benefits relate to stated objectives.
8.Costs: Understand what costs are included.
9.Distribution: Consider how benefits and costs are distributed.
10.Symmetrical treatment: Ensure that benefits and costs are presented symmetrically.
One of the strongest and most consistent predictors of self-regulated driving is gender, with women more likely than men to limit their driving in situations like bad weather or at night. However, studies have focused more on documenting these gender patterns than on explaining the processes underlying them, which may vary in their implications for transportation, health and ageing policy. Our study addresses this issue by examining two potential explanations for women's greater likelihood of self-regulated driving: their greater health limitations and use of driving alternatives. Using a nationally representative sample of older Americans (2011 National Health and Aging Trends Study, N = 4,842), we conducted logistic regressions predicting driving under four limitations: alone, at night, in rain or other bad weather and on highways. Our results provide stronger support for the driving alternatives explanation, especially women's greater reliance on rides from family and friends. Health limitations do contribute to explaining one of the self-regulated driving behaviours – avoiding driving alone. Our findings suggest that willingness to use driving alternatives is part of transitioning from driving. However, the relatively low use of all the alternatives we examined points to the importance of better understanding older adults’ transportation needs and preferences, including their gendered dimensions.
We are losing the climate change mitigation challenge. The task now before us: minimize the impacts.
The status of the climate change mitigation challenge is analyzed and summarized. Pressures spawned by industrialization and population growth have driven unsustainable growth in greenhouse gas (GHG) emissions, yielding global warming. Such warming has accelerated over the last three years and for 2016 was 1.3 °C over pre-industrial levels. Serious climate change induced impacts have already occurred and more serious ones are projected. The recent UN Paris COP agreement is only a small step toward meaningful mitigation. It will only slow emission growth and will not lead to near term aggressive annual emission decreases, which are needed to avoid warming of 2 °C or more. We are losing the battle to protect the planet from unacceptable climate change impacts. To minimize the impacts, the following is needed: more aggressive communication of the seriousness of the problem to national leaders and the public, a serious adaptation program, a dramatically expanded RD&D program to accelerate the development of low cost low C technologies, with a focus on potentially transformational technologies, and a serious commitment to peak global emissions as soon as possible and drastically reduce such emissions annually from that point on. A global agreement to set a price on carbon (C) could be effective in helping to achieve such an aggressive emission reduction trajectory.
It’s hard to beat the energy density and convenience of liquid hydrocarbons. The product of energy used and journey time is another way to compare transportation systems. It is more practical to power electric cars from batteries than photovoltaics. Solar can be used to supply some of the energy needed to recharge the batteries. The primary energy used to make food, the fuel for the human cyclist, can be many times the calorific energy derived from the food.
Transportation is a major source of carbon dioxide emissions. Hermans makes some excellent points in his article “The challenge of energy-efficient transportation.” However primary energy to produce fuel should also be considered. The embodied energy of liquid hydrocarbon fuels is much less than their energy content. For a cyclist the fuel is food, and, depending on diet, the primary energy can be many times the food’s calorific energy. The article is over optimistic on the prospect of cars directly powered by solar photovoltaics. It’s more realistic to use batteries in electric cars and generate the electricity from a number of sources. For anything other than trains that run on fixed tracks it’s hard to beat the energy density and convenience of liquid hydrocarbons.
We examine how stress has the potential to shape the character of the electron transport that occurs within ZnO. In order to narrow the scope of this analysis, we focus on a determination of the velocity-field characteristics associated with bulk wurtzite ZnO. Monte Carlo simulations of the electron transport are pursued for the purposes of this analysis. Rather than focusing on the impact of stress in of itself, instead we focus on the changes that occur to the energy gap through the application of stress, i.e., energy gap variations provide a proxy for the amount of stress. Our results demonstrate that stress plays a significant role in shaping the form of the velocity-field characteristics associated with ZnO. This dependence could potentially be exploited for device application purposes.
Pre-slaughter transportation may affect poultry welfare and mortality rates. A retrospective analysis was conducted to examine the effect of environmental, management and individual factors on the percentage of dead birds during pre-slaughter transportation (dead-on-arrival, DOA). The variables accounted for in the analyses included: environmental temperature, travel duration, genetic line, gender, crate type and crate stocking density. Among the 41 452 loads of turkeys (34 696 388 birds) and 3241 of end of lay hens (21 788 124 birds) transported to three large abattoirs in northern Italy in a 3-year period, the median DOA was 0.14% in turkeys, and 0.38% in hens. In turkeys, travel duration longer than 30 min, temperature higher than 26°C and high in-crate densities were associated with increased DOA. In winter (⩽2°C), high stocking densities did not reduce the mortality risk from cold stress; on the contrary, for stocking densities either near to or just above the maximum density in EC Reg. 1/2005, the DOA risk was greater than for loads with densities of 10 kg/m2 less than the EC maximum. Male birds and specific genetic lines also showed a higher DOA. In hens, transportation lasting longer than 2 h and the brown-feathered breed were associated with higher DOA. Dead-on-arrival progressively increased with travel duration, remaining constant between 4 and 6 h and peaking at 8 h (median: 0.57%). The maximum DOA increase was detected during winter. These results show that several species-specific factors may lead to increased risk of mortality.
This article compiles and categorizes the various forms of climate risk facing the fossil fuel industry. The type and intensity of risk differs greatly among the three forms of fossil fuels, as well as between countries in the developing and developed world. The paper finds heightened risk for the coal industry and reduced risk for oil businesses, due to its lack of substitutes.
Burning coal, oil, and natural gas is the source of two-thirds of the world’s emissions of greenhouse gases. Sales of these fuels also represent the economic underpinning of resource-rich countries and the world’s largest firms. As such, steps taken to abate emissions undermine commercial opportunities to monetize fossil fuel reserves. Risks to the industry correlate with progress on climate goals.
This article analyzes recent literature on climate action strategy and finds that a new or intensified set of risks has arisen for the fossil fuel industry. These include government policies and legislation, financial restrictions among lenders and insurers, hostile legal and shareholder actions, changes in demand and geopolitics, as well as the onset of new competitive forces among states and technologies.
The exposure of carbon-based businesses to these risks and the potential for loss is neither distributed uniformly across the sector, nor adheres to a uniform time scale. Shareholder-owned firms in the developed world will be incentivized to react sooner than large state-owned resource owners in developing countries. The fates of the three fossil fuels also appear likely to play out differently. Demand for oil appears insulated by its lack of viable substitutes, while coal businesses are already undergoing climate-related action, pushed by decreasing social acceptance and constraining financial regulation. At the other end of the spectrum, climate action has improved the medium-term viability of low-carbon natural gas. What appears clear is that, as effects of climate change grow more pronounced, the industry faces a future that is less accepting of current practices.
The efficiencies of present-day modes of transportation are reviewed. Future sustainable options are discussed.
Transportation takes about 20% of the energy use worldwide , and this figure is likely to increase. The fact that transportation requires some form of mobile energy storage makes this topic especially challenging for the post-fossil-fuel era. When looking at alternatives, we should realize that nothing matches the energy density of liquid fuels like gasoline or diesel, if the system as a whole is considered. It is, therefore, important to consider the efficiency of various modes of transportation. To assess the possibilities of improvements in efficiency, a brief introduction into the physics of transportation is given first. Subsequently, the efficiencies of present-day modes of transportation—cars, buses, trains, air transport, and bicycles—are reviewed. Finally, new technologies relying on biofuel, electricity, solar power, and hydrogen are discussed.