The Industrial Platinum Cycle for Russia: A Case Study of Materials Accounting

Platinum is a strategic resource for the world economy and appears to be unsubstitutable in many of its uses. As a consequence, establishing its life cycle and quantifying net increases and decreases may serve as a basis for detecting lifecycle wide opportunities for increasing recycling and reuse of platinum. With this aim, we have characterized the platinum cycle for the Russian Federation for the year 2000. It was found that most of the platinum produced in Russia was exported immediately(21,300 kg Pt/yr (82%)), while the remainder was stockpiled (2,200 kg Pt/yr (8.5%)) or used domestically (2,450 kg Pt/yr, (9.4%)). Russia has a continuing reliance on fabricated platinum imports (1,600 kg Pt/yr). Recovery of platinum from waste and scrap is undeveloped, although there are significant domestic sources, particularly the military sector

Should we mine the deep seafloor?

As land-based mineral resources become increasingly difficult and expensive to acquire, the potential for mining resources from the deep seafloor has become widely discussed and debated. Exploration leases are being granted, and technologies are under development. However, the quantity and quality of the resources are uncertain, and many worry about risks to vulnerable deep-sea ecosystems. Deep-sea mining has become part of the discussion of the United Nations Sustainable Development Goals. In this article we provide a summary of benefits, costs, and uncertainties that surround this potentially attractive but contentious topic

Flow and Fates of Discarded Copper in Sofia, Bulgaria, and New Haven CT, USA

In order to better understand the fate of copper following its use, the discard flows of copper were analyzed in Sofia, Bulgaria, and New Haven, CT, USA. These cities were chosen to compare discard copper generation and recovery between a city in a developed country and a city in a developing country. The comparison between these two cities can be problematic due to their different relative sizes, and generalizing the results to other cities cannot be done without some error. However, as the first study of its kind, this study provides insights into the relative copper recovery rates indifferent socioeconomic contexts. The total yearly per capita copper discards from in-use stocks in Sofia were found to be about 1.9 kg/person (for year 2003), while New Haven has total yearly per capita copper discards from in-use stocks of about 4.7kg/person (for year 2000). The associated recovery rates for copper in both cities are quite high, at about 87% in New Haven, and 97% in Sofia. The higher per capita copper discards and the lower recovery rate in New Haven is thought to be attributable to the higher average income level relative to Sofia

Addressing decision making for remanufacturing operations and design-for-remanufacture

Remanufacturing is a process of returning a used product to at least original equipment manufacturer original performance specification from the customers' perspective and giving the resultant product a warranty that is at least equal to that of a newly manufactured equivalent. This paper explains the need to combine ecological concerns and economic growth and the significance of remanufacturing in this. Using the experience of an international aero-engine manufacturer it discusses the impact of the need for sustainable manufacturing on organisational business models. It explains some key decision-making issues that hinder remanufacturing and suggests effective solutions. It presents a peer-validated, high-level design guideline to assist decision-making in design in order to support remanufacturing. The design guide was developed in the UK through the analysis of selections of products during case studies and workshops involving remanufacturing and conventional manufacturing practitioners as well as academics. It is one of the initial stages in the development of a robust design for remanufacture guideline

A Northern Hemisphere Volcanic Chemistry Record (1869-1984) and Climatic Implications using a South Greenland Ice Core

The effect of volcanic emISSIOn of acidic aerosols on climate is well documented. The presence of acid droplets in the stratosphere can reduce transmissivity and hence decrease surface temperatures. Since the amount and chemical composition of erupted material has important effects on regional climate, knowledge of past volcanic events is of extreme importance. Detailed glaciochemical records provide the only milieu wherein the geochemistry of paleovolcanic events can be fully documented. We present a detailed sulfate and chloride record from an ice core drilled at site 20 D, 40 km SW of Dye 3 in southern Greenland. The record spans the time period 1869-1984 with chemical analyses of approximately eight samples per year. Time series decomposition and locally weighted scatter plot smoothing techniques were used to extract long term trends from the data so that individual volcanic eruptions could be documented. A number of events identified here have been unnoticed previously and a high percentage of the major chemical signatures documenting these events is associated with large decreases in temperature in the latitudinal zone 60-90° N. Many authors have pointed out that the amount of volcanic acids such as HCI and H2S04 injected into the atmosphere has a very important influence on global climate, yet this volcanic input has been difficult to quantify prior to ~1960. Our data help to alleviate this problem. These individual events can be compared to available frost tree ring data from North America, further establishing a volcanism—climatic linkage

Parametrization of C-shocks. Evolution of the Sputtering of Grains

Context: The detection of narrow SiO lines toward the young shocks of the L1448-mm outflow has been interpreted as a signature of the magnetic precursor of C-shocks. In contrast with the low SiO abundances (<10E-12) in the ambient gas, the narrow SiO emission at almost ambient velocities reveals enhanced SiO abundances of 10E-11. This enhancement has been proposed to be produced by the sputtering of the grain mantles at the first stages of C-shocks. However, modelling of the sputtering of grains has usually averaged the SiO abundances over the dissipation region of C-shocks, which cannot explain the recent observations. Aims: To model the evolution of the gas phase abundances of SiO, CH3OH and H2O, produced by the sputtering of grains as the shock propagates through the ambient gas. Methods: We propose a parametric model to describe the physical structure of C-shocks as a function of time. Using the known sputtering yields for water mantles (with minor constituents like silicon and CH3OH) and olivine cores by collisions with H2, He, C, O, Si, Fe and CO, we follow the evolution of the abundances of silicon, CH3OH and H2O ejected from grains. Results: The evolution of these abundances shows that CO seems to be the most efficient sputtering agent in low velocity shocks. The velocity threshold for the sputtering of silicon from the grain mantles is reduced by 5-10 km s-1 by CO compared to other models. The sputtering by CO can generate SiO abundances of 10E-11 at the early stages of low velocity shocks, consistent with those observed in the magnetic precursor of L1448-mm. Our model also satisfactorily reproduce the progressive enhancement of SiO, CH3OH and H2O observed in this outflow by the coexistence of two shocks with vs=30 and 60kms-1 within the same region.Comment: 12 pages, 7 figures, accepted for publication in A&

CID: Chemistry in disks VI.sulfur-bearing molecules in the protoplanetary disks surrounding LkCa15, MWC480, DM Tau, and GO Tau

We study the content in S-bearing molecules of protoplanetary disks around low-mass stars. We used the new IRAM 30-m receiver EMIR to perform simultaneous observations of the $1_{10}-1_{01}$ line of H$_2$S at 168.8 GHz and $2_{23}-1_{12}$ line of SO at 99.3 GHz. We compared the observational results with predictions coming from the astrochemical code NAUTILUS, which has been adapted to protoplanetary disks. The data were analyzed together with existing CS J=3-2 observations. We fail to detect the SO and H$_2$S lines, although CS is detected in LkCa15, DM\,Tau, and GO\,Tau but not in MWC\,480. However, our new upper limits are significantly better than previous ones and allow us to put some interesting constraints on the sulfur chemistry. Our best modeling of disks is obtained for a C/O ratio of 1.2, starting from initial cloud conditions of H density of $2\times 10^5$ cm$^{-3}$ and age of $10^6$ yr. The results agree with the CS data and are compatible with the SO upper limits, but fail to reproduce the H$_2$S upper limits. The predicted H$_2$S column densities are too high by at least one order of magnitude. H$_2$S may remain locked onto grain surfaces and react with other species, thereby preventing the desorption of H$_2$S