| 1. |
- Tilton, John E., et al.
(författare)
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Public policy and future mineral supplies
- 2018
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Ingår i: Resources policy. - : Elsevier. - 0301-4207 .- 1873-7641. ; 57, s. 55-60
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Tidskriftsartikel (refereegranskat)abstract
- A widespread and pessimistic view of the availability of mineral commodities calls for strong government initiatives to ensure adequate future supplies. This article provides a more market oriented and optimistic perspective, one that focuses on production costs and prices rather than physical availability. It sees short-run shortages continuing to plague commodity markets in the future as in the past. Though painful while they last, these shortages are temporary and do not pose a serious long-run threat to human welfare. Moreover, even without government intervention, they self-correct. The sharply higher prices that they evoke create strong incentives that foster supply and curb demand.Potentially more serious are long-run shortages due to mineral depletion. Such shortages are often thought to be inevitable, a conclusion that flows directly from the physical view of depletion. For various reasons, we reject this view of depletion in favor of an economic view. The latter recognizes that depletion may create long-run shortages, but stresses that this need not be the case if new technology can continue to offset the cost-increasing effects of depletion in the future as it has in the past. The economic view also suggests that a list of mineral commodities most threatened by depletion can best be compiled using cumulative availability curves rather than the more common practice of calculating commodity life expectancies based on estimates of available stocks.
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| 2. |
- Lee, Jordy, et al.
(författare)
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Reviewing the material and metal security of low-carbon energy transitions
- 2020
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Ingår i: Renewable & Sustainable Energy Reviews. - : Elsevier BV. - 1364-0321. ; 124, s. 109789-109789
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Forskningsöversikt (refereegranskat)abstract
- The global transition to a low-carbon economy will involve changes in material markets and supply chains on a hitherto unknown scale and scope. With these changes come numerous challenges and opportunities related to supply chain security and sustainability. To help support decision-making as well as future research, this study employs a problem-oriented perspective while reviewing academic publications, technical reports, legal documents, and published industry data to highlight the increasingly interconnected nature of material needs and geopolitical change. The paper considers a broad set of issues including technologies, material supplies, investment strategies, communal concerns, innovations, modeling considerations, and policy trends to help contextualize policy decisions and regulatory responses. Policy options are outlined for each topical section, as well as areas for further research. Together, these recommendations serve to help guide the complex, interdisciplinary approach to materials required for a low-carbon transition.
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| 3. |
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| 4. |
- Radetzki, Marian, et al.
(författare)
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The boom in mineral markets : how long might it last?
- 2008
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Ingår i: Resources policy. - : Elsevier BV. - 0301-4207 .- 1873-7641. ; 33:3, s. 125-128
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Tidskriftsartikel (refereegranskat)abstract
- The commodity price boom that emerged in 2004 has proved far more persevering than its predecessors of 1950 and 1973. Some analysts have suggested that it may represent the start of a "supercycle" caused by the voracious raw materials demand from China and other emerging economies, with prices remaining high for 20-30 years. We offer an alternative explanation. For a variety of reasons, the establishment of new capacity in minerals and energy to match the accelerated demand trends is more time consuming than commonly assumed, and may take a decade or longer. As soon as the new capacity is in place, however, the boom will be punctuated. Prices may collapse much earlier in the event of a severe recession that cuts the growth in commodity demand.
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| 5. |
- Riley, John K., et al.
(författare)
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Ionic Surfactant Binding to pH-Responsive Polyelectrolyte Brush-Grafted Nanoparticles in Suspension and on Charged Surfaces
- 2015
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Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 31:51, s. 13680-13689
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Tidskriftsartikel (refereegranskat)abstract
- The interactions between silica nanoparticles grafted with a brush of cationic poly(2-(dimethylamino) ethyl methacrylate) (SiO2-g-PDMAEMA) and anionic surfactant sodium dodecyl sulfate (SDS) is investigated by dynamic light scattering, electrophoretic mobility, quartz crystal microbalance with dissipation, ellipsometry, and atomic force microscopy. SiO2-g-PDMAEMA exhibits pH-dependent charge and size properties which enable the SDS binding to be probed over a range of electrostatic conditions and brush conformations. SDS monomers bind irreversibly to SiO2-g-PDMAEMA at low surfactant concentrations (similar to 10(-4) M) while exhibiting a pH-dependent threshold above which cooperative, partially reversible SDS binding occurs. At pH 5, SDS binding induces collapse of the highly charged and swollen brush as observed in the bulk by DLS and on surfaces by QCM-D. Similar experiments at pH 9 suggest that SDS binds to the periphery of the weakly charged and deswollen brush and produces SiO2-g-PDMAEMA/SDS complexes with a net negative charge. SiO2-g-PDMAEMA brush collapse and charge neutralization is further confirmed by colloidal probe AFM measurements, where reduced electrosteric repulsions and bridging adhesion are attributed to effects of the bound SDS. Additionally, sequential adsorption schemes with SDS and SiO2-g-PDMAEMA are used to enhance deposition relative to SiO2-g-PDMAEMA direct adsorption on silica. This work shows that the polyelectrolyte brush configuration responds in a more dramatic fashion to SDS than to pH-induced changes in ionization, and this can be exploited to manipulate the structure of adsorbed layers and the corresponding forces of compression and friction between opposing surfaces.
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| 6. |
- Saigal, Trishna, et al.
(författare)
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Poly(ethylene oxide) star polymer adsorption at the silica/aqueous interface and displacement by linear poly(ethylene oxide)
- 2013
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Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 29:12, s. 3999-4007
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Tidskriftsartikel (refereegranskat)abstract
- Multiarm star copolymers with approximately 460 poly(ethylene oxide) (PEO) arms that have a degree of polymerization N = 45 were synthesized via atom transfer radical polymerization (ATRP) of PEO-methacrylate macromonomers in the presence of divinyl benzene cross-linkers. These are an example of molecular or nanoparticulate brushes that are of interest as steric stabilizers or boundary lubrication agents when adsorbed from solution to a solid/aqueous interface. We use ellipsometry to measure adsorption isotherms at the silica/aqueous interface for PEO star polymers and linear PEO chains having molecular weights comparable either to the star polymer or to the individual arms. The compactness of the PEO star polymers (molecular weight 1.2 × 106) yields a saturation surface excess concentration that is approximately 3.5 times greater than that of the high molecular weight (1 × 106) linear PEO. Adsorption of low molecular weight (6000) linear PEO was below the detection limit. Competitive adsorption experiments were conducted with ellipsometry, complemented by independent quartz crystal microbalance with dissipation (QCM-D) measurements. Linear PEO (high molecular weight) displaced preadsorbed PEO star polymers over the course of approximately 1.5 h, to form a mixed adsorbed layer having not only a significantly lower overall polymer surface excess concentration, but also a significantly greater amount of hydrodynamically entrapped water. Challenging a preadsorbed linear PEO (high molecular weight) layer with PEO star polymers produced no measurable change in the overall polymer surface excess concentration, but changes in the QCM-D energy dissipation and resonance frequency suggested that the introduction of PEO star polymers caused a slight swelling of the layer with a correspondingly small increase in entrapped water content.
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| 7. |
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| 8. |
- Svedberg, Peter, et al.
(författare)
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Long-term trends in the Real real prices of primary commodities : Inflation bias and the Prebisch-Singer hypothesis
- 2011
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Ingår i: Resources policy. - : Elsevier BV. - 0301-4207 .- 1873-7641. ; 36:1, s. 91-93
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Tidskriftsartikel (refereegranskat)abstract
- In his recent article on measuring the long-term trends in the real prices of primary commodities, Cuddington (2010) extends in several important respects our earlier efforts (Svedberg and Tilton, 2006) to correct real commodity price trends for biases in the Consumer Price Index and other deflators. First, he argues for a log-linear relationship between prices and time. Second, he proposes a simple and quick method for obtaining corrected price trends from the published but uncorrected estimates. Finally, he illustrates, for the case of copper and presumably for many other commodities as well, the difficulties of obtaining real price trends significantly different from zero when the log values of the price data contain a unit root, requiring the use of difference stationary models. We welcome these insights, which should improve and make easier efforts to estimate correctly real commodity price trends over the long run. We would stress, however, that it is still important to correct for the biases in inflation indices, notwithstanding the failure of difference stationary models to obtain long-run real price trends (both corrected and uncorrected) significantly different from zero.
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| 9. |
- Svedberg, Peter, et al.
(författare)
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The Real, Real Price of Nonrenewable Resources : Copper 1870-2000
- 2003
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Over the past 40 years economists have devoted considerable effort to estimating long-run trends in real commodity prices. The results indicate that the real prices for many commodities have fallen, suggesting to the surprise of many that resource scarcity is declining over time. Almost all of this work, however, uses the U.S. producer price index or other standard price deflators, which recent research shows overestimate inflation for several reasons. This article examines copper prices with adjusted deflators designed to eliminate this bias. It finds that the trend over time, which is significantly downward when no adjustment is made to the deflator, displays no tendency in either direction or is significantly upward depending on the magnitude of the deflator adjustment employed. These findings suggest that real resources prices provide less support than widely assumed for the hypothesis that resources are becoming more available or less scarce over time.
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| 10. |
- Söderholm, Patrik, et al.
(författare)
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Material efficiency : an economic perspective
- 2012
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Ingår i: Resources, Conservation and Recycling. - : Elsevier BV. - 0921-3449 .- 1879-0658. ; 61:2, s. 75-82
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Tidskriftsartikel (refereegranskat)abstract
- This article presents an economic perspective of material efficiency, and discusses the role of public policy in providing market incentives for a more efficient use of materials. In doing so, it comments on the engineering approach to material efficiency presented by Allwood et al. (2011) in an earlier issue of Resources, Conservation and Recycling. We argue that concerns over potential future natural resource scarcities do not represent a strong motive for introducing policies to foster greater material efficiency but that various environmental externalities and information failures in the relevant material markets do. Moreover, in such instances policy makers should opt for policy measures that target the relevant market failures (e.g., environmental damages) as closely as possible. This normally means avoiding policies that directly encourage specific material efficiency options. Policy measures that address particular environmental problems and information externalities will enhance material efficiency in a more effective manner. This is because ex ante it is difficult for policy makers to know in what ways and by how much to alter material production and use.
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