A multi-dimensional indicator for material and energy circularity: Proof-of-concept of exentropy in Li-ion battery recycling.

Recycling processes are an important stage in the raw material life cycle, as it enables the transition from a linear economy into a circular one. However, the currently available indicators of productivity in recycling technologies respond to the needs of a linear economy. In this work, a parameter called "exentropy" is proposed, offering the possibility to simultaneously account for mass preservation and the energy efficiency of transformative stages. As a proof-of-concept of this indicator, the analysis of a lithium-ion battery recycling process under various concentrations of a leaching reagent (i.e., 0.1M, 1M, and 2M) is presented. It is shown that, when the energy or mass dimensions are considered independently, the processes considered optimal may have conflicting characteristics. In contrast, the multi-dimensional analysis identified the process option offering the best compromise for both material and energy preservation, an aspect closer to the goals of the circular economy.

Giant clam (Tridacna) distribution in the Gulf of Oman in relation to past and future climate.

The Oman upwelling zone (OUZ) creates an unfavorable environment and a major biogeographic barrier for many coral reef species, such as giant clams, thus promoting and maintaining faunal differences among reefs on the east and west side of the Arabian Peninsula. We record the former existence of Tridacna in the Gulf of Oman and review its stratigraphic distribution in the Persian Gulf to provide new insights on the connectivity of coral reef habitats around southern Arabia under changing climate and ocean conditions. Fossil shells were carbon-14 dated and employed as sclerochronological proxy archives. This reveals that the Omani population represents a last glacial colonization event during the Marine Isotope Stage 3 interstadial under colder-than-present temperatures and variable upwelling intensity linked to Dansgaard-Oeschger climate oscillations. It was favored by temperatures just above the lower threshold for the habitat-forming reef coral communities and instability of the upwelling barrier. We conclude that the distribution of Tridacna in the northern Arabian Sea is generally limited by either strong upwelling or cool sea surface temperature under gradually changing climate conditions at the interglacial-glacial scale. Opportunities for dispersal and temporary colonization existed only when there was a simultaneous attenuation of both limiting factors due to high-frequency climate variability. The OUZ will unlikely become a future climate change refuge for giant clams because they will be exposed either to thermal stress by rapid anthropogenic Indian Ocean warming or to unfavorable upwelling conditions.

Slow-growing reef corals as climate archives: A case study of the Middle Eocene Climatic Optimum 40 Ma ago.

The skeletons of stony corals on tropical shallow-water reefs are high-resolution climate archives. However, their systematic use for unlocking climate dynamics of the geologic past is limited by the susceptibility of the porous aragonite skeleton to diagenetic alterations. Here, we present oxygen and carbon isotope time series (monthly resolution) from reef corals with an unusual unaltered preservation from the Middle Eocene Climatic Optimum (MECO) "hyperthermal" (40 million years ago). Annual extension of the corals at the studied midlatitude site (France) was remarkably low (0.2 cm). Nonetheless, isotope signatures display no evidence for kinetic disequilibria that discredit their use as climate archive, but growth rate-dependent annual signal amplitude attenuations need corrections using an innovative sampling approach. Thereafter, we present evidence of symbiotic zooxanthellae in reef corals of the Paleogene and subdued sea surface temperature seasonality of only 7° to 8°C during the MECO, consistent with the globally equant climate of the hothouse.

High coral reef connectivity across the Indian Ocean is revealed 6-7 Ma ago by a turbid-water scleractinian assemblage from Tanzania (Eastern Africa).

The present centre of coral diversity in the Western Indian Ocean is defined by the northern Mozambique Channel with an extension northward to Mafia Island in Tanzania (Eastern Africa). The geological and evolutionary history of this hotspot of marine biodiversity remains so far completely obscure, because Cenozoic fossil reef communities of this area are not well known. This study presents a new fossil scleractinian fauna from the Mikindani Formation in southern Tanzania. It comprises 16 symbiotic coral taxa of which nine could be identified to the species and five to the genus level. Coral habitat consisted of low-relief biostromes that developed in shallow water at the front of the Rovuma Delta under conditions of variable sediment input. The biostromes are dated to be Messinian based on associated calcareous nannoplankton and planktic foraminifers. The studied coral assemblage shows close affinities with the Recent Western Indian Ocean biogeographic province and Central Indo-West Pacific biogeographic region as well as with the Miocene of Indonesia. Faunistic relations with the Oligocene-early Miocene of Somalia and Iran do not exist. The patterns of species distribution document a major palaeobiogeographic change in the Indian Ocean that correlates with the onset of the Miocene Indian Ocean Equatorial Jet during the middle Miocene. The clear Indonesian affinity of the Messinian coral fauna from southern Tanzania implies that this westerly oceanic surface current provided high biogeographic connectivity across the Indian Ocean during the late Miocene. Today, the coastal waters of Indonesia are located in the Coral Triangle. Diversification of this global epicentre of marine biodiversity started in the early Miocene and it was established already during the middle Miocene. Our results indicate that the East African hotspot of coral biodiversity originated as an offshoot of the Coral Triangle in the middle to late Miocene.

Early Miocene reef- and mudflat-associated gastropods from Makran (SE-Iran).

A new gastropod fauna of Burdigalian (early Miocene) age is described from the Iranian part of Makran. The fauna comprises 19 species and represents three distinct assemblages from turbid water coral reef, shallow subtidal soft-bottom and mangrove-fringed mudflat environments in the northern Indian Ocean. Especially the reef-associated assemblage comprises largely new species. This is explained by the rare occurrence of reefs along the northern margin of the Miocene Indian Ocean and the low number of scientific studies dealing with the region. In terms of paleobiogeography, the fauna corresponds well to coeval faunas from the Pakistani Balochistan and Sindh provinces and the Indian Kathiawar, Kutch and Kerala provinces. During the early Miocene, these constituted a discrete biogeographic unit, the Western Indian Province, which documents the near complete biogeographic isolation from the Proto-Mediterranean Sea. Some mudflat taxa might represent examples of vicariance following the Tethys closure. The fauna also displays little connection with coeval faunas from Indonesia, documenting a strong provincialism within the Indo-West Pacific Region during early Miocene times. Neritopsis gedrosiana sp. nov., Calliostoma irerense sp. nov., Calliostoma mohtatae sp. nov. and Trivellona makranica sp. nov. are described as new species.

Orbitally paced phosphogenesis in Mediterranean shallow marine carbonates during the middle Miocene Monterey event.

During the Oligo-Miocene, major phases of phosphogenesis occurred in the Earth's oceans. However, most phosphate deposits represent condensed or allochthonous hemipelagic deposits, formed by complex physical and chemical enrichment processes, limiting their applicability for the study regarding the temporal pacing of Miocene phosphogenesis. The Oligo-Miocene Decontra section located on the Maiella Platform (central Apennines, Italy) is a widely continuous carbonate succession deposited in a mostly middle to outer neritic setting. Of particular interest are the well-winnowed grain to packstones of the middle Miocene Bryozoan Limestone, where occurrences of authigenic phosphate grains coincide with the prominent carbon isotope excursion of the Monterey event. This unique setting allows the analysis of orbital forcing on phosphogenesis, within a bio, chemo, and cyclostratigraphically constrained age-model. LA-ICP-MS analyses revealed a significant enrichment of uranium in the studied authigenic phosphates compared to the surrounding carbonates, allowing natural gamma-radiation (GR) to be used as a qualitative proxy for autochthonous phosphate content. Time series analyses indicate a strong 405 kyr eccentricity forcing of GR in the Bryozoan Limestone. These results link maxima in the GR record and thus phosphate content to orbitally paced increases in the burial of organic carbon, particularly during the carbon isotope maxima of the Monterey event. Thus, phosphogenesis during the middle Miocene in the Mediterranean was controlled by the 405 kyr eccentricity and its influence on large-scale paleoproductivity patterns. Rare earth element data were used as a tool to reconstruct the formation conditions of the investigated phosphates, indicating generally oxic formation conditions, which are consistent with microbially mediated phosphogenesis.

Parascolymia (Scleractinia: Lobophylliidae) in the Central Paratethys Sea (Vienna Basin, Austria) and its possible biogeographic implications.

Palaeobiogeographical and palaeodiversity patterns of scleractinian reef corals are generally biased due to uncertain taxonomy and a loss of taxonomic characters through dissolution and recrystallization of the skeletal aragonite in shallow marine limestones. Herein, we describe a fossil lobophylliid coral in mouldic preservation from the early middle Miocene Leitha Limestone of the Central Paratethys Sea (Vienna Basin, Austria). By using grey-scale image inversion and silicone rubber casts for the visualization of the original skeletal anatomy and the detection of distinct micromorphological characters (i.e. shape of septal teeth, granulation of septocostae) Parascolymia bracherti has been identified as a new species in spite of the dissolved skeleton. In the recent era, Parascolymia like all Lobophylliidae is restricted to the Indo-Pacific region, where it is represented by a single species. The new species proves the genus also in the Miocene Mediterranean reef coral province. A review of the spatio-temporal relationships of fossil corals related to Parascolymia indicates that the genus was probably rooted in the Eastern Atlantic‒Western Tethys region during the Paleocene to Eocene and reached the Indo-Pacific region not before the Oligocene. The revealed palaeobiogeographical pattern shows an obvious congruence with that of Acropora and tridacnine bivalves reflecting a gradual equatorwards retreat of the marine biodiversity center parallel to the Cenozoic climate deterioration.

Correlating carbon and oxygen isotope events in early to middle Miocene shallow marine carbonates in the Mediterranean region using orbitally tuned chemostratigraphy and lithostratigraphy.

During the Miocene prominent oxygen isotope events (Mi-events) reflect major changes in glaciation, while carbonate isotope maxima (CM-events) reflect changes in organic carbon burial, particularly during the Monterey carbon isotope excursion. However, despite their importance to the global climate history they have never been recorded in shallow marine carbonate successions. The Decontra section on the Maiella Platform (central Apennines, Italy), however, allows to resolve them for the first time in such a setting during the early to middle Miocene. The present study improves the stratigraphic resolution of parts of the Decontra section via orbital tuning of high-resolution gamma ray (GR) and magnetic susceptibility data to the 405 kyr eccentricity metronome. The tuning allows, within the established biostratigraphic, sequence stratigraphic, and isotope stratigraphic frameworks, a precise correlation of the Decontra section with pelagic records of the Mediterranean region, as well as the global paleoclimatic record and the global sea level curve. Spectral series analyses of GR data further indicate that the 405 kyr orbital cycle is particularly well preserved during the Monterey Event. Since GR is a direct proxy for authigenic uranium precipitation during increased burial of organic carbon in the Decontra section, it follows the same long-term orbital pacing as observed in the carbon isotope records. The 405 kyr GR beat is thus correlated with the carbon isotope maxima observed during the Monterey Event. Finally, the Mi-events can now be recognized in the δ18O record and coincide with plankton-rich, siliceous, or phosphatic horizons in the lithology of the section.

Correlating Mediterranean shallow water deposits with global Oligocene-Miocene stratigraphy and oceanic events.

Shallow-marine sediment records have the strong potential to display sensitive environmental changes in sedimentary geometries and skeletal content. However, the time resolution of most neritic carbonate records is not high enough to be compared with climatic events as recorded in the deep-sea sediment archives. In order to resolve the paleoceanographic and paleoclimatic changes during the Oligocene-Miocene transition in the Mediterranean shallow water carbonate systems with the best possible time resolution, we re-evaluated the Decontra section on the Maiella Platform (central Apennines, Italy), which acts as a reference for the correlation of Oligocene-Miocene shallow water deposits in the Mediterranean region. The 120-m-thick late Oligocene-late Miocene carbonate succession is composed of larger foraminiferal, bryozoan and corallinacean limestones interlayered with distinct planktonic foraminiferal carbonates representing a mostly outer neritic setting. Integrated multi-proxy and facies analyses indicate that CaCO3 and total organic carbon contents as well as gamma-ray display only local to regional processes on the carbonate platform and are not suited for stratigraphic correlation on a wider scale. In contrast, new biostratigraphic data correlate the Decontra stable carbon isotope record to the global deep-sea carbon isotope record. This links relative sea level fluctuations, which are reflected by facies and magnetic susceptibility changes, to third-order eustatic cycles. The new integrated bio-, chemo-, and sequence stratigraphic framework enables a more precise timing of environmental changes within the studied time interval and identifies Decontra as an important locality for correlating not only shallow and deep water sediments of the Mediterranean region but also on a global scale.

Global warming and South Indian monsoon rainfall-lessons from the Mid-Miocene.

Precipitation over India is driven by the Indian monsoon. Although changes in this atmospheric circulation are caused by the differential seasonal diabatic heating of Asia and the Indo-Pacific Ocean, it is so far unknown how global warming influences the monsoon rainfalls regionally. Herein, we present a Miocene pollen flora as the first direct proxy for monsoon over southern India during the Middle Miocene Climate Optimum. To identify climatic key parameters, such as mean annual temperature, warmest month temperature, coldest month temperature, mean annual precipitation, mean precipitation during the driest month, mean precipitation during the wettest month and mean precipitation during the warmest month the Coexistence Approach is applied. Irrespective of a ~ 3-4 °C higher global temperature during the Middle Miocene Climate Optimum, the results indicate a modern-like monsoonal precipitation pattern contrasting marine proxies which point to a strong decline of Indian monsoon in the Himalaya at this time. Therefore, the strength of monsoon rainfall in tropical India appears neither to be related to global warming nor to be linked with the atmospheric conditions over the Tibetan Plateau. For the future it implies that increased global warming does not necessarily entail changes in the South Indian monsoon rainfall.

Informal electronic waste recycling: a sector review with special focus on China.

Informal recycling is a new and expanding low cost recycling practice in managing Waste Electrical and Electronic Equipment (WEEE or e-waste). It occurs in many developing countries, including China, where current gaps in environmental management, high demand for second-hand electronic appliances and the norm of selling e-waste to individual collectors encourage the growth of a strong informal recycling sector. This paper gathers information on informal e-waste management, takes a look at its particular manifestations in China and identifies some of the main difficulties of the current Chinese approach. Informal e-waste recycling is not only associated with serious environmental and health impacts, but also the supply deficiency of formal recyclers and the safety problems of remanufactured electronic products. Experiences already show that simply prohibiting or competing with the informal collectors and informal recyclers is not an effective solution. New formal e-waste recycling systems should take existing informal sectors into account, and more policies need to be made to improve recycling rates, working conditions and the efficiency of involved informal players. A key issue for China's e-waste management is how to set up incentives for informal recyclers so as to reduce improper recycling activities and to divert more e-waste flow into the formal recycling sector.

Modeling the combustion behavior of hazardous waste in a rotary kiln incinerator.

Hazardous wastes have complex physical forms and chemical compositions and are normally incinerated in rotary kilns for safe disposal and energy recovery. In the rotary kiln, the multifeed stream and wide variation of thermal, physical, and chemical properties of the wastes cause the incineration system to be highly heterogeneous, with severe temperature fluctuations and unsteady combustion chemistry. Incomplete combustion is often the consequence, and the process is difficult to control. In this article, modeling of the waste combustion is described by using computational fluid dynamics (CFD). Through CFD simulation, gas flow and mixing, turbulent combustion, and heat transfer inside the incinerator were predicted and visualized. As the first step, the waste in various forms was modeled to a hydrocarbon-based virtual fuel mixture. The combustion of the simplified waste was then simulated with a seven-gas combustion model within a CFD framework. Comparison was made with previous global three-gas combustion model with which no chemical behavior can be derived. The distribution of temperature and chemical species has been investigated. The waste combustion model was validated with temperature measurements. Various operating conditions and the influence on the incineration performance were then simulated. Through this research, a better process understanding and potential optimization of the design were attained.

Aluminium recycling and environmental issues of salt slag treatment.

Environmental friendly recycling is the trend toward total recycling of aluminium metal. In the secondary aluminium industry, due to the complexity of compositions and contaminants in the various types of aluminium scraps, an understanding of the behavior of different scraps during melting is crucial in the recycling process. Salt slags are the byproducts of the secondary aluminium industry, which should be recycled and processed in a proper way by taking the environmental impact into consideration. This article provides qualitative assessment on 10 different commercial aluminium scraps for their relative recyclability via well-designed and controlled laboratory experiments. It confirms that more nonmetallic contaminants, smaller size, and higher ratio of surface area to body volume generally lead to a lower metal recovery. Recycling the scraps with lower recyclability normally generates more salt slags. High slag viscosity leads to more fine aluminum metal entrapped in the salt slag and thus increases the load of salt slag recycling. It was found that viscosity of the salt flux is increased with the amount of entrapped nonmetallic components, which affect the settling of heavier materials. In addition, the slag samples from the melting tests were leached and analyzed to evaluate the behavior of carbon containing scrap. The elevated carbon content in the scrap resulted in more carbide formation in salt slags and thus more methane generation in salt slag recycling with a higher environmental impact.