| 1. |
|
|
| 2. |
|
|
| 3. |
- Ju, YeoJin, et al.
(författare)
-
Long-term change in uranium migration processes in highly eroded granite, demonstrated by uranium series disequilibrium in fracture-filling materials
- 2023
-
Ingår i: Applied Geochemistry. - : Elsevier. - 0883-2927 .- 1872-9134. ; 148
-
Tidskriftsartikel (refereegranskat)abstract
- The mineralization and mobilization of uranium (U) are strongly associated with subsurface redox processes, which can affect the U inventory of deep geological repositories of nuclear waste and are to be considered in safety assessments. The Korea Atomic Energy Research Institute (KAERI) underground research tunnel (KURT) is located in an active groundwater recharge area in granitic bedrock, where oxidizing meteoric water infiltrates the subsurface through permeable zones of highly weathered granite, forming multiple redox fronts. Fracture-filling materials (FFMs) are U-enriched, with concentrations of up to ∼50 mg/kg. We examined long-lived radioactive isotopes of 230Th, 232Th, 234U, 235U, and 238U and other redox-sensitive elements and isotopes, e.g., Fe, δ56Fe, and Ce/Ce*, in the FFMs to understand fluctuations in redox conditions in the granitic fracture system. The primary focus was on U migration processes and to decipher the depths of meteoric water infiltration over geological timescales. Enrichment of uranium and other redox-sensitive elements occurred in FFMs at relatively shallow depths (∼180 m below ground level, bgl), implying that the U distribution was associated with redox interactions of the intruding groundwater that precipitated the secondary minerals. Interaction of FFMs with groundwater caused activity ratios (AR) of the FFMs to deviate moderately from secular equilibrium (AR = 1); 234U/238U AR of 0.87–1.25, and 230Th/238U AR of 0.76–1.22. A dynamic redox transition zone, witnessed by uranium series disequilibrium, shows both deposition and complex redistribution in the 120–205 Ka time frame, is confined to the upper ∼180 m bgl of the fractured rock. The results provide new insights into the long-term paleo-redox processes in the complex granitic fracture systems, which are analogs of potential deep-seated geological repositories for high-level radioactive waste.
|
|
| 4. |
- Kang, Hyokyeong, et al.
(författare)
-
Relaxation of Stress Propagation in Alloying-Type Sn Anodes for K-Ion Batteries
- 2024
-
Ingår i: Small Methods. - 2366-9608. ; 8:1
-
Tidskriftsartikel (refereegranskat)abstract
- Alloying-type metallic tin is perceived as a potential anode material for K-ion batteries owing to its high theoretical capacity and reasonable working potential. However, pure Sn still face intractable issues of inferior K+ storage capability owing to the mechanical degradation of electrode against large volume changes and formation of intermediary insulating phases K4Sn9 and KSn during alloying reaction. Herein, the TiC/C–carbon nanotubes (CNTs) is prepared as an effective buffer matrix and composited with Sn particles (Sn–TiC/C–CNTs) through the high-energy ball-milling method. Owing to the conductive and rigid properties, the TiC/C–CNTs matrix enhances the electrical conductivity as well as mechanical integrity of Sn in the composite material and thus ultimately contributes to performance supremacy in terms of electrochemical K+ storage properties. During potassiation process, the TiC/C–CNTs matrix not only dissipates the internal stress toward random radial orientations within the Sn particle but also provides electrical pathways for the intermediate insulating phases; this tends to reduce microcracking and prevent considerable electrode degradation.
|
|
| 5. |
|
|
| 6. |
- Kumar, Eva, et al.
(författare)
-
Defluoridation from aqueous solutions by granular ferric hydroxide (GFH)
- 2009
-
Ingår i: Water Research. - : Elsevier BV. - 0043-1354 .- 1879-2448. ; 43:2, s. 490-498
-
Tidskriftsartikel (refereegranskat)abstract
- This research was undertaken to evaluate the feasibility of granular ferric hydroxide (GFH) for fluoride removal from aqueous solutions, Batch experiments were performed to study the influence of various experimental parameters such as contact time (1 min-24 h), initial fluoride concentration (1-100 mg L(-1)), temperature (10 and 2S degrees C), pH (3-12) and the presence of competing anions on the adsorption of fluoride on GFH. Kinetic data revealed that the uptake rate of fluoride was rapid in the beginning and 95% adsorption was completed within 10 min and equilibrium was achieved within 60 min. The sorption process was well explained with pseudo-first-order and pore diffusion models. The maximum adsorption capacity of GFH for fluoride removal was 7.0 mg g(-1). The adsorption was found to be an endothermic process and data conform to Langmuir model. The optimum fluoride removal was observed between pH ranges of 4-8. The fluoride adsorption was decreased in the presence of phosphate followed by carbonate and sulphate. Results from this study demonstrated potential utility of GFH that could be developed into a viable technology for fluoride removal from drinking water.
|
|
| 7. |
|
|
| 8. |
- Ahmed, Mohammad Shamsuddin, et al.
(författare)
-
Multiscale Understanding of Covalently Fixed Sulfur–Polyacrylonitrile Composite as Advanced Cathode for Metal–Sulfur Batteries
- 2021
-
Ingår i: Advanced Science. - : Wiley. - 2198-3844 .- 2198-3844. ; 8:21
-
Forskningsöversikt (refereegranskat)abstract
- Metal–sulfur batteries (MSBs) provide high specific capacity due to the reversible redox mechanism based on conversion reaction that makes this battery a more promising candidate for next-generation energy storage systems. Recently, along with elemental sulfur (S8), sulfurized polyacrylonitrile (SPAN), in which active sulfur moieties are covalently bounded to carbon backbone, has received significant attention as an electrode material. Importantly, SPAN can serve as a universal cathode with minimized metal–polysulfide dissolution because sulfur is immobilized through covalent bonding at the carbon backbone. Considering these unique structural features, SPAN represents a new approach beyond elemental S8 for MSBs. However, the development of SPAN electrodes is in its infancy stage compared to conventional S8 cathodes because several issues such as chemical structure, attached sulfur chain lengths, and over-capacity in the first cycle remain unresolved. In addition, physical, chemical, or specific treatments are required for tuning intrinsic properties such as sulfur loading, porosity, and conductivity, which have a pivotal role in improving battery performance. This review discusses the fundamental and technological discussions on SPAN synthesis, physicochemical properties, and electrochemical performance in MSBs. Further, the essential guidance will provide research directions on SPAN electrodes for potential and industrial applications of MSBs.
|
|
| 9. |
- Ahuja, Vishal, et al.
(författare)
-
Microbial alchemy : upcycling of brewery spent grains into high-value products through fermentation
- 2023
-
Ingår i: Critical reviews in biotechnology. - : Taylor & Francis. - 0738-8551 .- 1549-7801.
-
Forskningsöversikt (refereegranskat)abstract
- Spent grains are one of the lignocellulosic biomasses available in abundance, discarded by breweries as waste. The brewing process generates around 25–30% of waste in different forms and spent grains alone account for 80–85% of that waste, resulting in a significant global waste volume. Despite containing essential nutrients, i.e., carbohydrates, fibers, proteins, fatty acids, lipids, minerals, and vitamins, efficient and economically viable valorization of these grains is lacking. Microbial fermentation enables the valorization of spent grain biomass into numerous commercially valuable products used in energy, food, healthcare, and biomaterials. However, the process still needs more investigation to overcome challenges, such as transportation, cost-effective pretreatment, and fermentation strategy. to lower the product cost and to achieve market feasibility and customer affordability. This review summarizes the potential of spent grains valorization via microbial fermentation and associated challenges.
|
|
| 10. |
- Anctil, Annick, et al.
(författare)
-
Status report on emerging photovoltaics
- 2023
-
Ingår i: JOURNAL OF PHOTONICS FOR ENERGY. - : SPIE-SOC PHOTO-OPTICAL INSTRUMENTATION ENGINEERS. - 1947-7988. ; 13:4
-
Tidskriftsartikel (refereegranskat)abstract
- This report provides a snapshot of emerging photovoltaic (PV) technologies. It consists of concise contributions from experts in a wide range of fields including silicon, thin film, III-V, perovskite, organic, and dye-sensitized PVs. Strategies for exceeding the detailed balance limit and for light managing are presented, followed by a section detailing key applications and commercialization pathways. A section on sustainability then discusses the need for minimization of the environmental footprint in PV manufacturing and recycling. The report concludes with a perspective based on broad survey questions presented to the contributing authors regarding the needs and future evolution of PV.(c) 2023 Society of Photo-Optical Instrumentation Engineers (SPIE)
|
|
