Substance Flow Analysis of Zinc in Two Preheater–Precalciner Cement Plants and the Associated Atmospheric Emissions

Atmospheric emission of heavy metals from different anthropogenic sources is a great concern to human beings due to their toxicities. In order to disclose the emission levels and the distribution patterns of zinc (Zn) in the modern cement industry with respect to its low boiling point (~900 °C) comparing to the high-temperature (1450 °C) clinker production process, solid samples representing the input and output flow of Zn during the entire production process in two preheater–precalciner cement plants (CPs) were collected and analyzed. For the first time, it was found that the behaviour of Zn inside different precalciner CPs was similar despite a huge difference in the Zn inputs to the CPs; namely, almost all the Zn input was output in clinker, which was then mixed with different additives and retarder to make cement products. The high-temperature clinkerisation process would incorporate Zn into the aluminosilicate of clinker. As a result, there was no enrichment of Zn during clinker production and the atmospheric emission factor was relatively low at 0.002%, or 1.28–9.39 mg Zn·t−1 clinker. Our result for the atmospheric Zn emissions from CPs was much lower than most previous reports, implying the CPs were not a crucial Zn emission source. However, the higher load of Zn in some raw/alternative materials—like nonferrous smelting slag with a Zn content of ~2%—could greatly increase the content of Zn in clinker and cement products. Therefore, further investigation on the environmental stability of Zn in such Zn-laden cement and concrete should be carried out.

Environmental Stability and Long-term Variability of Harpacticoid Copepod Assemblages

Harpacticoid copepods of the Chernaya Bay (White Sea) intertidal zone were collected in 45 surveys carried out from spring to autumn over a 25-year period (1996-2020) at three sites that differed in sediment properties. There were no significant long-term trends or seasonal cycles in total abundance. Regarding the species composition, the differences between sites were the most important source of variability over the whole period while the fine-scale (within-habitat) variability was low. Epibenthic species prevailed in fine silty sand, both burrowing and epibenthic species prevailed in medium sand, and interstitial and burrowing species prevailed in coarse sand. A comparison of the data on harpacticoid assemblages from a number of geographically remote loci corroborated the generality of this pattern. In the temporal dimension, the structure of each community was stable until the early 2000s, when the proportion of epibenthic, burrowing and interstitial species changed following changes in sediment properties (increasing siltation at sandy sites and decreasing siltation at the silty site). At each site, there was an increasing long-term trend in diversity (both in total richness and in expected species number). This increase was particularly apparent at sandy sites because of the appearance of epibenthic species. We suggest that sediment composition is the key factor determining the composition of harpacticoid assemblages in space and time. The “ecomorphological profile”, i.e., the proportion of species with different lifestyle and morphological traits, is a useful and informative indicator for describing and typifying these assemblages.

Ultra-thin foldable transparent electrodes composed of stacked silver nanowires embedded in polydimethylsiloxane

We have prepared an ultra-thin flexible transparent conductive electrode with high folding endurance composed of randomly arranged silver nanowires (AgNWs) embedded in polydimethylsiloxane (PDMS). A simple preparation method was performed to connect a glass substrate coated with a AgNW network and a glass substrate coated with PDMS. The glass substrate was then removed after the PDMS solidified, and the AgNW–PDMS composite film was peeled off. Moreover, the problem of the high contact resistance caused by the random arrangement of AgNWs was solved by the local joule heat generated by applying voltage to both sides of the AgNW–PDMS composite structure to weld the overlapping AgNWs. The sheet resistance (Rs ) of AgNW–PDMS composite films with different AgNW deposition concentrations decreased by 46.4%–75.8% through this electro-sintering treatment. The embedded structure of the AgNW–PDMS composite ensures better voltage resistance and environmental stability under high temperature and humidity conditions compared with a AgNW network attached to a glass substrate. Additionally, the substrate-free, excellent elasticity and high resilience characteristics resulted in the Rs value of the same composite electrode only increasing by 2.9 ohm/sq after folding four times. The advantage of the metal thermal conductivity makes the joule heat generated by electric injection rapidly diffuse and dissipate in the AgNW-based transparent heater with faster response time and smaller voltage drive than indium tin oxide.

High-performance photodetector based on an interface engineering-assisted graphene/silicon Schottky junction

Graphene/silicon Schottky junctions have been proven efficient for photodetection, but the existing high dark current seriously restricts applications such as weak signal detection. In this paper, a thin layer of gadolinium iron garnet (Gd3Fe5O12, GdIG) film is introduced to engineer the interface of a graphene/silicon Schottky photodetector. The novel structure shows a significant decrease in dark current by 54 times at a −2 V bias. It also exhibits high performance in a self-powered mode in terms of an Ilight/Idark ratio up to 8.2 × 106 and a specific detectivity of 1.35 × 1013 Jones at 633 nm, showing appealing potential for weak-light detection. Practical suitability characterizations reveal a broadband absorption covering ultraviolet to near-infrared light and a large linear response with a wide range of light intensities. The device holds an operation speed of 0.15 ms, a stable response for 500 continuous working cycles, and long-term environmental stability after several months. Theoretical analysis shows that the interlayer increases the barrier height and passivates the contact surface so that the dark current is suppressed. This work demonstrates the good capacity of GdIG thin films as interlayer materials and provides a new solution for high-performance photodetectors.

Solution-Processed Smooth Copper Thiocyanate Layer with Improved Hole Injection Ability for the Fabrication of Quantum Dot Light-Emitting Diodes

Copper thiocyanate (CuSCN) has been gradually utilized as the hole injection layer (HIL) within optoelectronic devices, owing to its high transparency in the visible range, moderate hole mobility, and desirable environmental stability. In this research, we demonstrate quantum dot light-emitting diodes (QLEDs) with high brightness and current efficiency by doping 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ) in CuSCN as the HIL. The experimental results indicated a smoother surface of CuSCN upon F4TCNQ doping. The augmentation in hole mobility of CuSCN and carrier injection to reach balanced charge transport in QLEDs were confirmed. A maximum brightness of 169,230 cd m−2 and a current efficiency of 35.1 cd A−1 from the optimized device were received by adding 0.02 wt% of F4TCNQ in CuSCN, revealing promising use in light-emitting applications.

Environmental Dynamics of the Ribbon-Like Pine Forests in the Parklands of North Kazakhstan

The ribbon-like pine forests of North Kazakhstan represent the principal territorial intrazonal and azonal biotopes. Integrated bio-geographic studies of the pine forests’ status were performed in the Beskaragai and Chaldai Nature Reserves in the Pri-Irtysh River basin within, at present, the climate–change most susceptible transitional parkland-steppe zone of Central Asia, adjoining the West Siberian Lowland. The investigations followed the regional topographic gradient with a series of mapped sites characterizing the spatial relief patterns of the pristine forest distribution and the associated phytocenoses. The results revealed marked natural arboreal cover restoration differences between the geographically close upland and lowland forest ecosystems. The regional tree growth dynamics show the varying intensity of the pine seedlings’ succession, the tree stands’ biomass productivity and the environmental stability, weakened by the extreme continentality and progressing aridification along with adverse anthropogenic ecological impacts. The specific geomorphic, soil and hydrological conditions are the principal determining factors. The more vital plain and lowland pine forests host the floristically richer fescue-dominated communities compared to the more fragile and precipitation-poorer upland pine settings. The latter forest ecosystems display a higher vulnerability to the current climate change, generating tree drying, forest fires, and to modern human activities such as logging, herding and recreation. The research conclusions provide new insights on the natural ribbon-like pine forests’ sustainability and adaptation to the ongoing continental warming triggering fundamental environmental transformations in Central Asia’s parklands.

Analysis of Mapping Forest, Settlement, and Rice Field Areas in Konawe Selatan District, Indonesia

The rampant land-use change in Konawe Selatan District and the uncontrolled use leads to disaster and environmental stability effect, consequently, mapping the area function is important for controlling land-use activities to reduce the risk of disaster. Therefore, this study aims to determine the direction, distribution, and effective area of the function of forests, settlements, and rice fields. This study used a regional survey with a quantitative approach. Base map data of administrative, slope class, soil type, rainfall, and land-use obtained from the regional planning agency and SAS Planet were used and analyzed with quantitative descriptive analysis overlayed with scoring. The result showed that the direction of area functions was dominated by limited production forests by 50.05% while the distribution of protected forest function was spread across 14 sub-districts with limited production forests in all sub-districts, production forests in 17 sub-districts, settlements in 21 sub-districts, and rice fields in 9 sub-districts. Furthermore, the effective area shows that all area functions are accordance with the directions, except for rice fields which took over the function of forest while the effective area controlled by the regional planning shows that all area functions need correction following the regulation of the Minister of Agriculture of Indonesia. Areas which do not accordance with the function need to be evaluated, hence, regional planning is required to be revised by the people's representative in Konawe Selatan. Keywords: Analysis; Forest; Rice field; Settlement; Mapping Copyright (c) 2021 Geosfera Indonesia and Department of Geography Education, University of Jember This work is licensed under a Creative Commons Attribution-Share A like 4.0 International License