Main Phase Research Articles

Nature-based interventions to support mental health and well-being of young women in pregnancy: exploratory work for future feasibility RCT.

The prevalence of mental health and well-being issues among young women is increasing. Pregnancy is a time when new mental health challenges may arise, or existing conditions can be exacerbated. This project presents preparatory work on how nature-based interventions may help to support the mental health and well-being of young pregnant women (aged 16-24 years) in a future study. This project was formed of three main phases conducted from March to August 2022: (1) mapping nature activities available across the East Midlands region and two focus groups with providers of nature activities (n = 6); (2) public participation and involvement work to inform future research. This included four focus groups with young women (n = 11), leading to the formation of a new young women's panel (Research Influencers Group). Networking and stakeholder engagement to support future research. The mapping survey identified 68 nature-based organisations/projects operating in the region, many of whom expressed interest in being involved in future research. The young women's focus groups confirmed the importance of the topic and generated a wealth of information to support the intervention design. A Research Influencer Group of five young women was established from the focus group participants. The Research Influencer Group chose the nature-based intervention and had input into all aspects of the study design. This group will continue into future projects. Focus groups with providers of nature activities have further advanced the study design. The project team have developed relationships with relevant stakeholders and networks that will inform the future trial. This preparatory co-design work suggested that a nature-based intervention may be acceptable to young women, and providers of such interventions felt it was feasible to offer these activities to young pregnant women. This preparatory work has led to an outline research plan which has been co-produced with public contributors and stakeholders throughout. This preparatory work is limited by small focus group samples, and the possibility that not all providers were reached through the snowballing approach to the mapping survey. Future research is needed to test the nature-based intervention; this would be in the form of a feasibility randomised controlled trial of nature-based interventions to promote the mental health and well-being of young pregnant women. This article presents independent research funded by the National Institute for Health and Care Research (NIHR) Public Health Research programme as award number NIHR135167.

Spatial-temporal tendencies of the ice regime of the Dnipro Cascade reservoirs

Formulation of the problem. Knowledge about the formation, destruction and trends of the ice regime of rivers and reservoirs is very important for hydropower, shipping, fisheries, etc. There are almost no studies that evaluated the trends, homogeneity and stationarity of the ice regime of the Dnipro Cascade reservoirs. At the same time, such research is relevant especially in the conditions of a changing climate. The objective of this paper is evaluation of spatio-temporal trends of a observation series for the ice regime of the Dnipro Cascade reservoirs based on a complex approach using statistical and graphical methods. Methods. The research used statistical methods, namely the Pearson method for establishing of the trend equation in the time series and the correlation coefficient between variables, and the Mann-Kendell statistical non-parametric test for assessing the statistical significance of the trend. Among the graphic methods, the mass curve and residual mass curve were used to assess the homogeneity and stationarity of observation series, respectively, as well as combined chronological graphs for spatial analysis, determination of synchronous and in-phase (or on the contrary) long-term cyclic fluctuations of the ice regime characteristics at various water gauges. The research was carried out based on the observation data for dates of ice appearance, ice freeze-up, ice break-up (i.e., melt onset), ice disappearance for 35 water gauges. Results. According to the Mann-Kendall statistical test, contradictory results were obtained regarding the stationarity of the observation series of the ice regime of the Dnipro Cascade reservoirs. At the same time, according to graphic analysis, such series turned out to be quasi-homogeneous and quasi-stationary, since they have unfinished phases of increase and decrease of long-term cyclical fluctuations. In turn, the cyclic fluctuations are characterized by synchronous and in-phase, which indicates the same temporal and spatial tendencies of the ice regime of six reservoirs. The dates of the appearance of main phases of the ice regime of the Dnipro Cascade reservoirs are characterized by significant variability. Scientific novelty and practical significance. For the first time, modern knowledge about the ice regime characteristics of the Dnipro Cascade reservoirs were obtained based on the simultaneous application of statistical and graphical methods. In addition, the research results can be used for further research, namely any statistical processing (determination of probabilistic characteristics, search for prognostic dependencies, generalizations, etc.).

Upper Jurassic Source Rock Evaluation and Thermal Maturity Evolution of the NW Sab’Atayn Basin, Yemen

Of Yemen’s Mesozoic basins, the Sab’atayn Basin offers the most significant potential for oil and gas exploration. The key consideration in the evaluation of source rocks to hydrocarbon exploration is the quantity and nature of the organic materials in sedimentations. Using organic geochemistry and total organic carbon content, organic-rich sediments from the Meem (Lower) and Lam (Upper) members from four wells in the NW Sab’atayn Basin were evaluated. The information gained reveals that the Meem source rocks have a total organic carbon content (TOC) value between 0.2–1.68 wt%, therefore suggests fair to very good source rocks. Only two samples in the Kamaran-01 well had values greater than 3 wt%, compared to the Lam source rocks’ values, which range from 0.2 to 3.81 wt%, which suggest excellent source rocks. The majority of the samples are made up of reworked organic debris, with no possibility for interesting source rocks, according to the Rock-Eval pyrolysis data. The majority of the Meem and Lam source rocks samples under study have Tmax values below 440 °C, placing them in the immature to marginally mature and on the main periphery of main phases of hydrocarbon formation. Based on the results of the Meem source rocks’ generative potential (GP), it may be inferred that non-generative rocks status of Meem source rocks due to GP values less than 2 mg HC/gm rock. Additionally, if the burial depth is sufficient to generate the necessary temperature and pressure, source rocks with extraordinarily high GP values of more than 10 mg Hc/g rock may serve as an efficient source rock for the Dahamr Ali-01 well. On the other hand Lam source rock is classified as moderate source rocks. Non-generative potential has been reported from Lam source rock in Himyar-01 well where the GP is less than 1 mg HC/g rock. The cross-plots of pyrolysis characteristics, such as HI versus Tmax (modified van Krevelen diagram) and TOC vs S2, which are most likely the result of deposition of more terrigenous type III organic materials derived from terrestrial in the study area, can be used to determine the kerogen type for Lam and Meem source units. The analysis of Meem source rocks demonstrated that they are typically plotted in the mature zone; however samples of Lam source rocks proved that they have been still immature, merely marginally mature in the Dahamr Ali-01 and Saba-01 wells.

The Northern Ireland Cohort for the Longitudinal Study of Ageing (NICOLA): Harmonised Cognitive Assessment Protocol (HCAP) dress rehearsal review.

AbstractBackgroundNICOLA, the largest public health cohort study of ageing in Northern Ireland, commenced in 2013 with a representative sample of ∼8500 individuals aged 50 years and over living across Northern Ireland.HCAP is a National Institute on Ageing (NIA) funded sub‐study designed to assess prevalence of cognitive impairment and dementia in a sample of 1000 participants aged 65 years and older.A dress rehearsal was carried out prior to the main study to implement the study as per the HCAP study protocol. This, ensured any issues could be identified prior to the main phase and the Standard Operating Procedures (SOP) could be amended accordingly.Method14 participant interviews and 14 informant interviews were completed between December 2021 and January 2022.The HCAP dress rehearsal sample was selected from the NICOLA research advisory panel, which included NICOLA participants and individuals from the charity group AgeNI.The study consisted of a face‐to‐face participant interview, comprising nineteen different measures of memory and thinking.During the informant interview a family member or friend was asked about participant’s ability to perform daily tasks and their social and cognitive activities.During the HCAP dress rehearsal, fieldwork staff conducted home visits in pairs: one conducting the interview while the other observed. Staff completed feedback forms which provided opportunities to comment on the use of computer software, consent processes and the administration of memory and thinking assessments.ResultSeveral areas for improvement were highlighted:Pre‐Visit Documentation: Fieldwork staff reflected on the complexities of test administration and the transition between computer and paper assessments. Pre‐visit protocols were revised to include preparation processes.Test Administration: Queries were raised on the logistics of test administration and scoring. These were resolved through contact with the Health and Retirement Study (HRS) team.Study Administration Processes: Additional administration databases were created and SOPs amended to ease the flow of recruitment and home visit bookings.ConclusionThe HCAP dress rehearsal highlighted the importance of pre‐visit preparation and staff training, combined with clear procedures and protocols to allow for the collection of high quality data and enhancement of the study experience for participants and researchers.

Occurrence of Large Geomagnetically Induced Currents Within the EPRI SUNBURST Monitoring Network

AbstractSpace weather, a natural hazard, can adversely impact human technological assets. High‐voltage electric power transmission grids constitute one of the most critical technological systems vulnerable to space weather driven geomagnetically induced currents (GICs). One of the major challenges pertaining to the study of GICs over the continental United States has been the availability of GIC measurements, which are critical for validation of geoelectric field and power flow models, for example. In this study, we analyze GIC measurements collected at 17 Electrical Power Research Institute (EPRI) SUNBURST transformer locations across the United States for which a GIC value of 10 A or greater was recorded. This data set includes 52 individual geomagnetic storms with Kp index 6 and above during the period from 2010 to 2021. The analysis confirms that there is a good correlation between the number of geomagnetic storms per year and the number of recorded GIC events. Our results also show that about 76% of the top 17 GIC events are associated with the storm main phase, while only 24% are attributed to storm sudden commencements. In addition, it is shown, for the first time, that mid‐latitude positive bays can cause large GICs over the continental United States. Finally, this study shows that the largest measured GIC event in the data set was associated with a localized intense dB/dt structure, which could be attributed to substorm activity.

Assessing the Efficacy of Reflective Game Design: A Design-Based Study in Digital Game-Based Learning

Reflective learning is widely recognised as a highly effective approach to learning. It involves learners in a process wherein they reflect on their past experiences to improve their skills and knowledge. In recent years, there has been growing recognition of the capacity of games to facilitate experiential learning. Therefore, this research aimed to evaluate the effectiveness of integrating reflective design principles into digital game-based learning (GBL). The focus was on assessing the reliability and appropriateness of reflective game design, as well as learner perceptions. This study adopted a participatory design approach, ensuring the active involvement of the target audience across all extensive phases. The research consisted of three main phases. Firstly, reflective learning was integrated into game design to develop the Reflective Game Design (RGD) framework. This development was guided by insights gathered from participants through both a user survey (N = 101) and semi-structured interviews (N = 15). Subsequently, a GBL digital game was developed based on the RGD framework in co-design sessions (N = 6). Finally, a prototype evaluation (N = 56) was conducted to assess the feasibility and practicality of implementing reflective game design within digital GBL contexts. Overall, the RGD approach and the game prototype received positive feedback in terms of engagement, content clarity, the incorporation of reflective game elements, and player immersion. This study contributes to the literature by providing principles and guidelines for RGD, thus offering valuable insights for researchers, educators, and game designers looking to create effective educational games.

Precipitation Kinetics of Water-Cooled Copper Mold Al-Mg-Si(-Mn, Zr) Alloy during Aging

The aging precipitation behavior of 6061 aluminum alloy that underwent iron casting and water-cooled copper casting and 6061 aluminum with Mn and Zr elements added was studied. Firstly, the hardness curves, tensile properties, and fracture morphology of four aging alloys—6061 (iron mold casting), 6061 (water-cooled copper mold casting), 6061-0.15Mn-0.05Zr (iron mold casting), and 6061-0.15Mn-0.05Zr (water-cooled copper mold casting)—were studied. The results of the aging hardness curve show that the aging precipitated phase of the 6061 alloy cast with a water-cooled copper mold is dispersed. The addition of Mn increases the amount of coarse inclusion α-(AlMnFeSi) in the alloy, resulting in a decrease in the age hardening property. The addition of Zr is related to the nucleation and growth of the G.P. region in the early aging period, mainly changing the formation rate and quantity of the G.P. region, leading to the advancement of peak aging and an increase in hardness. After the G.P. region gradually transforms into the β phase, the hardness of the alloy increases with the increase in the volume fraction of the β phase. When the β″ phase is coarsened to the point where the fault line can be bypassed, the transitional metastable β′ phase begins to precipitate, and the coherent distortion around it weakens, indicating over-aging. Finally, the equilibrium phase Mg2Si is formed. The results of the tensile tests indicate that the tensile strength and yield strength of the 6061-0.15Mn-0.05Zr alloy produced by water-cooled copper casting after aging are 356 Mpa and 230 Mpa, respectively. These values are 80 MPa and 75 MPa higher, respectively, than those of the 6061 aluminum alloy produced via iron casting. However, the elongation is by 5%. The fracture morphology of the tensile sample of the aging alloy shows that dislocation slip in the alloy results in dislocation plugging, stress concentration, and the initiation of crack cleavage on the surface. The fracture of the water-cooled copper mold-casting alloy is a ductile fracture of the microporous aggregation type, and the macroscopic fracture exhibits an obvious “neck shrinkage” phenomenon. The fracture analysis is consistent with the mechanical properties. The DSC curve shows that there is no enrichment process of solute atoms during the heating process, and the aging precipitation process after homogenization is as follows: G.P. zone → β″ phase → β′ phase. The aging precipitation process of the water-cooled copper casting alloy after homogenization treatment is as follows: β″ phase → β′ phase (no precipitation in the G.P. zone was observed). The results of the differential scanning calorimetry (DSC) analysis show that the main strengthening phase in the experimental alloy system is the β″ phase. The activation energies for the β″ phase precipitation were calculated and found to be 147 KJ/mol, 217 KJ/mol, 185 KJ/mol, and 235 KJ/mol, respectively. Additionally, a kinetic equation for the β″ phase precipitation during alloy aging was fitted.

Calcium Carbonate Precipitation Behavior in the System Ca-Me2+-CO3-H2O (Me2+ = Co, Ni, Cu, Fe): Ion Incorporation, Effect of Temperature and Aging

Crystalline calcium carbonates (CCCs) are among the most widespread minerals on the Earth’s surface and play a crucial role in the global carbon cycle, heavy metal sorption and incorporation. Among the numerous factors that influence the precipitation of CCCs from solution, the most determinant are the presence of additives in the mineral-forming medium, temperature, and crystallization time (aging time). The current work fills the gaps in the study of calcium carbonate crystallization from heavy metal (Me2+ = Co, Ni, Cu Fe)-containing solutions (Me2+/Ca 0.005–1.600) at different temperatures (3 and 23 °C) and aging times (21–158 days). The resulting precipitates were studied using optical and scanning electron microscopy, powder X-ray diffraction and energy-dispersive X-ray spectroscopy. Three crystalline calcium carbonates (synthetic analogues of calcite, aragonite and monohydrocalcite), as well as amorphous carbonate (AC), were found in the resulting precipitates. Temperature and aging time have a considerable effect on the phase composition, morphology and heavy metal content in CCCs. Low temperature (3 °C) and short aging times are generally favorable for the formation of monohydrocalcite and amorphous carbonate, while calcite tends to form at a higher temperature (23 °C) and in long-term experiments. Heavy metals can be incorporated into the calcite/monohydrocalcite crystal lattice in sufficient amounts, while aragonite can host a very small amount of Me2+ (or none). Calcite can concentrate Co (up to ~0.25 atoms per formula unit (apfu)) and Ni/Cu (up to ~0.05 apfu), while its Fe content is very close to the detection limits. Calcite precipitated at a higher Me2+/Ca ratio and temperature (23 °C) contains less Me2+ compared to calcite precipitated at a lower Me2+/Ca ratio and temperature (3 °C). Monohydrocalcite can host up to ~0.1 apfu of Co/Ni/Cu with no detectable preference for Me2+. The amount of Me2+ in monohydrocalcite decreases as aging time or temperature increases. It is worth noting that AC is the main carrier of heavy metals in the system being investigated and it should be considered the main host phase in heavy metal adsorption from aqueous solutions. The results obtained can be used to solve environmental issues and in mineral resource management.

NO Radiative Cooling and Ionospheric Response to the HILDCAA Events Following Geomagnetic Storms

AbstractNitric oxide infrared (5.3 µm) radiative cooling plays an important role in Earth's upper atmospheric energy balance during space weather events. Its behavior during a HILDCAA event following a geomagnetic storm can be more complicated than what is observed in an isolated geomagnetic storm (without HILDCAA). In order to understand this contrast, two moderate (SYM‐Hmin −80 nT; April 2005 (event‐1) and −65 nT; December 2006 (event‐2)), and an intense (Dstmin −150 nT; May 2000 (event‐3)) geomagnetic storms followed by HILDCAA events are considered for this study. It is found that, despite the larger solar wind‐magnetospheric energy coupling during the main phases of event‐1 and event‐2, the NO radiative cooling (NORC) and energetic electron precipitation (EEP) rates are larger during the HILDCAA phase. TIE‐GCM simulations indicate that the NORC pattern can be mainly attributed to variation in temperature, [O], and [NO] during HILDCAA. A larger rates of EEP due to the continuous substorm activity contributed to an additional ionization in D‐region and E‐region of the northern polar ionosphere during HILDCAA period of event‐2. This work is the first attempt to understand the NORC and EEP fluctuations during HILDCAA events preceded by geomagnetic events like event‐1 and event‐2. This study presents a comprehensive investigation of NORC and energetic electron (>27.93 keV) precipitation rate during HILDCAA event preceded by a moderate geomagnetic storm. An atmospheric chemistry‐based NORC emission model is used to understand the variation of NORC during intense geomagnetic storm (event‐3).

The Preparation, Microstructure, and Wet Wear Properties of an Fe55-Based Welding Layer with the Co-Addition of 0.01 wt% CeO2 and 1.5 wt% SiC Particles Using the Plasma Beam Spraying Method

Severe erosion wear is found on valve spools, which threatens the safety and reliability of these units. The use of the plasma beam spraying surfacing method can significantly improve the corrosion resistance and sealing performance of hydraulic valve spools, reduce material waste, and reduce maintenance costs. The effects of the co-addition of CeO2 and SiC particles on the morphology, surface cracks, microstructure, precipitated phases, and wear property of plasma-beam-sprayed Fe55-based coatings on 1025 steel were investigated using OM, EDS, ultra-deep field microscopy, and a wet sand rubber wheel friction tester, respectively. The dendrite exhibited a directional growth pattern perpendicular to the substrate and the transitional states of the microstructure with the co-addition of CeO2 and SiC particles. CeO2 or SiC reduced the liquid phase diffusion coefficient DL of Cr and C and resulted in a decrease in the G/R ratio. The dendrites changed into equiaxed grains. The main phase composition of the Fe55 welding layer was Cr7C3, γ-Fe. The martensite in the surfacing layer and the carbides formed Cr7C3, which can improve the hardness of the surfacing layer. The grain boundaries consisted mainly of a reticular eutectic structure. The uniform distribution of the Cr7C3 hard phase in the Fe55+1.5 wt% SiC+0.01 wt% CeO2 resulted in a uniformly worn surface. The sub-wear mechanisms during the friction process were micro-ploughing and micro-cutting. The hardness and toughness of Fe55+1.5 wt% SiC+0.01 wt% CeO2 were well-matched, avoiding excessive micro-cutting and microplastic deformation. A low content of CeO2 could lead to the formation of equiaxed grain and effectively improve the uniformity of the microstructure. The wear-resistant layer of Fe55+1.5 wt% SiC+0.01 wt% CeO2 can effectively improve the service life and long-term sealing performance of the valve spools.

Tribological and Mechanical Properties of Gradient Coating on Al2O3-Based Coating Produced by Detonation Spraying Methods

This work is aimed at obtaining gradient coating of aluminum oxide (Al2O3) by detonation spraying. The influence of technological parameters of spraying on the formation of structure, phase composition. mechanical, and tribological characteristics of Al2O3 coatings have been investigated. It was determined that coatings obtained from the same raw powder materials under different technological conditions show different structural and phase characteristics. X-ray diffraction analysis showed that when the barrel is filled with gas mixture by 56%, the coating with the main phase α-Al2O3 is formed, and when the barrel is filled with gas mixture by 63%, the coating with the main phase γ-Al2O3, which is relatively more ductile than α-Al2O3, is formed. It is determined that the α-Al2O3 formed mainly on the surface provides good wear resistance. The bottom layer composed of γ-Al2O3 phase, which is relatively more ductile than α-Al2O3, provides good adhesion of the coating to the substrate. Tribological study showed that the coating obtained at 56% of filling shows good wear resistance compared to other samples. At 63% of filling the results of scratch test showed good adhesive strength. By varying the technological mode of detonation sputtering (56%, 53%, and 63%), Al2O3 coating with gradient structure was obtained, in which γ-Al2O3 smoothly transitions to α-Al2O3 from the substrate to the surface. The hardness of the coatings was found to increase smoothly from substrate to surface (12.4–14.2 GPa).

The Distribution and Evolution of Storm Time Pc3‐5 ULF Wave Power Based on Satellite and Ground Observations

AbstractThe geomagnetic storm is an intense geomagnetic activity, and one important research aspect is the storm time ultralow frequency (ULF) waves, which can resonate with injected particles and impact particle dynamics in the inner magnetosphere. This study focuses on analyzing ULF wave power during geomagnetic storms on the ground, in the magnetosphere and in the solar wind. During the Van Allen Probe era from year 2012–2019, we identified 94 geomagnetic storm events with 25 as strong storms and 69 as moderate storms based on the variation of SYM‐H index. The analysis revealed that for both satellite and ground‐based measurements during storms with different intensity, the ULF wave power was dramatically enhanced in the main phase. In addition, the ULF wave power of strong storms was significantly stronger than that of moderate storms within the magnetosphere and on the ground. While the finding is opposite in the solar wind. Furthermore, the ULF wave power of strong storms exhibited a higher intensity at higher L shell values and in some cases, it can last up to ∼2 days. Besides, the ULF wave power displayed a linear correlation with the absolute value of the SYM‐H index during the storm main phase while it exhibited an exponential association with the absolute value of the SYM‐H index during the recovery phase. This comprehensive analysis offers valuable insights into the evolution of ULF waves in the inner magnetosphere during geomagnetic storm events, shedding light on plasma waves and wave‐particle interactions in this region.

Investigation of Evolution of Microstructure, Mechanical Properties, and Corrosion Resistance of Novel Al-Mg-Si-Ag Alloy

In this paper, the evolution of the microstructure, mechanical properties, and intergranular corrosion (IGC) resistance of an Al-Mg-Si-Ag alloy is systematically investigated. For the as-cast alloy, the microstructure consists of the Mg2Si phase and Mg32(Al, Ag)49 phase. In the isothermal aging process, the novel alloy presents a significant age hardening effect. The ultimate tensile strength (UTS) and yield strength (YS) of the peak-aged alloy are 342 MPa and 231 MPa, respectively, which are 53 MPa and 84 MPa higher than that of the as-quenched alloy. The main strengthening phase at the peak-aged stage of the alloy is the MgAg phase, which has a body-centered cubic structure with a lattice constant of a = 0.33 nm. In addition, the IGC resistance of the peak-aged alloy is worse than that of other aged alloys. The corresponding microstructure of GBPs of the peak-aged alloy is more consecutive, and this is the main reason for the deterioration of IGC resistance of the alloy.

Effect of Aging Treatment on the Strength and Microstructure of 7075-Based Alloys Containing 2% Li and/or 0.12% Sc

The present study was performed on three versions of 7075 alloy to which Sc or Sc + Li was added. The alloys were subjected to various aging treatments. The microhardness results show that the highest value of hardness was achieved when the alloy containing Li + Sc was aged at 120 °C for 24 h whereas the minimum level was exhibited by the base alloy aged at 280 °C. The results were interpreted in terms of the size and distribution of the main hardening phase (η′(MgZn2)), and the role of the presence of Al and Cu in the used alloy. Precipitation of Al3(Sc, Zr, Ti) phase particles during solidification of the Sc-containing ingots was also discussed. The coarsening and spheroidi-zation of η-phase particles take place through the Ostwald ripening mechanism while smaller par-ticles in solution dissolve and deposit on larger particles. In Sc-containing alloys, star phase particle consists of different layers. The change in the brightness from layer to layer indicates that the Zr and Sc concentrations are varied within the star phase, since the atomic number of Zr (40) is higher than the atomic number of Sc (21). The addition of Sc, as well, leads to marked decrease in the grain size of the as-cast alloys i.e., 300 µm and 45 µm, respectively. The interaction between Li and Sc would reduce the effectiveness of the grain refining effect of Sc. The results of the refining effect of Sc were confirmed using the EBSD technique.

Cobalt mineralization in the Northeastern Hunan Province of South China: New evidence from the Jintang hydrothermal Co polymetallic ore district

The hydrothermal vein-hosted Co deposits as one of the significant deposit types, have economic importance in the world. The Jiangnan Orogen of South China hosts abundant hydrothermal Co deposits, of which several Co (-polymetallic) deposits cluster together along the Changsha-Pingjiang fault zone in the northeastern Hunan Province. However, the variations of cobaltiferous mineral assemblages exhibit along the Changsha-Pingjiang fault zone. The Jintang ore district as the new prospecting target could provide an insight into the understanding of Co mineralization in the northeastern Hunan Province. The TIMA and EPMA results identify pyrite, arsenopyrite and minor cobaltite and glaucodot as the main cobaltiferous sulfide phases in the Jintang district, of which Co and Ni occur via substituting Fe in pyrite and arsenopyrite. In contrast with the barren pyrite (PyI) associated with marcasite in the early stage, the PyII of the middle stage is featured by the successive precipitation of Co-rich PyII-a (Avg. 2.93 wt%, up to 5.05 wt% Co), Ni-rich PyII-b (Avg. 1.56 wt%, up to 3.84 wt% Ni) and As-rich PyII-c (Avg. 1.36 wt%, up to 4.10 wt% As). The sharp chemical gradients across the different pyrite species as well as irregular reaction fronts indicate fluid-mediated dissolution and reprecipitation are principal mechanism for the incorporation of Co, Ni and As into sulfides. The fractionation of Co and Ni in pyrite was possibly caused by the decreasing salinity which favors high Ni/Co ratios in pyrite, rather than different fluid origins. Successively, the As-rich PyII-c together with arsenopyrite and glaucodot were precipitated, indicating a progressive increase of As concentrations in fluids and decreasing fO2 condition. The sulfur isotopic analyses yield the δ34SV-CDT values of −8.0 to −4.9 ‰ for the Jintang sulfides, suggesting both magma and wall rock as potential sulfur reservoirs. In combination with S and Pb isotopic results in this area, the Co mineralization in the northeastern Hunan Province was most likely formed via fluid-rock interactions along cataclastic fault zones with metal leached from the crystalline basement. The migration of ore-forming fluids along the Changsha-Pingjiang fault zone potentially contributed to the development of contrasting cobaltiferous mineral assemblages in the region, but the changes in local physicochemical conditions generated the partitioning of elements within a single deposit.

Microstructure and mechanical properties of selective laser melted Al-Zn-Mg-Si-Sc-Zr alloy with high hot-cracking resistance

A novel additive manufacturing dedicated Al-Zn-Mg-Si-Sc-Zr alloy is designed in this work, and its formability during selective laser melting (SLM) is investigated. Adding 3 % Si to the Al-Zn-Mg alloy leads to a refined microstructure and significant enhancement of hot-cracking resistance. By means of SEM, TEM and EBSD analysis some aspects of the alloy microstructure in as-built and thermal-treated states are discussed. Unlike traditional Al-Zn-Mg alloys, the main strengthening phase in the Al-Zn-Mg-Si-Sc-Zr alloy is Mg2Si, which forms a cellular structure and contributes to the favorable mechanical properties of the as-printed alloy. The as-built alloy exhibits a hardness of 138 HV, ultimate tensile strength (UTS) of 383 MPa, and elongation of 9.5 %. After solution and aging treatment, the UTS decreases to approximately 341–349 MPa, while the elongation increases to 17.6 %. However, with direct multistage aging treatment, the UTS can be increased to 409 MPa, albeit with a reduced elongation of 0.6–1.6 %. The variations in mechanical properties are attributed to the morphology of the Mg2Si phase and its coherent relationship with the Al matrix under different heat treatment processes.

Effect of ultrasonic impact treatment on the microstructure and properties of laser cladded CoCrFeNiMox high entropy alloy coatings

Ultrasonic impact technology was applied to improve the property of laser cladded CoCrFeNiMox (x = 0, 0.25, 0.5, 0.75) high entropy alloy coatings on the surface of low-carbon steel. The phase structures and the microstructural characteristics were studied in detail through X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The microhardness distributions, wear resistance, and corrosion resistance of the samples are illustrated using a microhardness tester, a micro-friction and wear tester, and an electrochemical test system. Single FCC phase solid solution was identified to be the main phase structure, with the interdendritic σ phase precipitating with the increasing Mo content. Although ultrasonic impact treatment did not change the phase composition of the high-entropy alloy (HEA) cladding coatings, evident plastic deformation and broken σ phase appeared near the surface of the impacted layers. Through the combined effects of dislocation, fine-grain, and dispersion strengthening, the microhardness of the CoCrFeNiMox coatings was improved after ultrasonic impact treatment. In addition, ultrasonic impact treatment decreased the surface roughness and increased the wear resistance, and the main wear mechanism of the impacted layers changed from fatigue spalling to abrasive wear. The wear mass of the ultrasonically impacted layers was approximately 92 % of the laser cladded CoCrFeNiMox coatings. Furthermore, ultrasonic impact treatment improved the corrosion resistance of the HEA coatings.

Cu and Co-modified SrTiO3 as materials for environmental applications

SrTiO3-based powder materials with the general formula: SrTi0.98Me0.02O3, Sr0.95Ti0.98Me0.02O3 and Sr0.9Ti0.9Me0.1O3 where Me = Cu, Co were synthesised by modified sol-gel method followed by the proper thermal treatment. For all materials, the particle size distribution had a bimodal character. The Energy Dispersive Spectroscopy (EDS) results showed that cobalt was regularly and homogeneously distributed in the materials, while for Cu-modified samples the areas enriched with copper were observed. The phase analysis implied that for all materials strontium titanate was the main phase, nevertheless for materials with the higher amount of Cu/Co introduced the additional phases CuO/Co3O4 were also observed. However, Temperature Programmed Reduction (TPR) results indicated the presence of oxide phases in all obtained materials. In addition, these results confirmed a more effective incorporation of cobalt than copper into the titanium sublattice in the perovskite structure. Moreover, X-ray Photoelectron Spectroscopy (XPS) results showed that copper exists in the materials on +I and +II oxidation states while cobalt takes +II and +III. The catalytic tests of SrTiO3-based materials in NH3-SCR and NH3-SCO reactions showed that Co-modified SrTiO3 were active in ammonia oxidation, while Cu-modified samples were active in both reactions but in different temperature ranges.

The Zacatín rock shelter (Granada, Spain): New data on the Mesolithic-Neolithic transition in the south-eastern Iberian coast

This study presents a holistic analysis of the occupation sequence at the rock shelter of Zacatín (Gualchos-Castell de Ferro, Granada, Spain), a site in the cliffs along Andalusia's Mediterranean coastline. Despite being disturbed by cave-ins and erosion, it offers valuable information on the transition between the Mesolithic hunter-gatherers and the first Neolithic farming communities in southern Iberia. The study adopted an approach combining stratigraphical and radiocarbon analyses with typological, archaeozoological and archaeobotanical classifications. The stratigraphical sequence comprises four main phases. The uppermost level (Phase 4) yielded a combination of modern and displaced prehistoric elements. Intermediate Phases 3 and 2 correspond to Early Neolithic layers ranging between the mid-6th to the beginning of the 5th millennium cal BC. The Neolithic finds consist of incised and impressed potsherds, stone tools, ornaments (perforated shells and discoidal beads) as well as domestic animals (caprines) and plant (cereals) species. Although the older Mesolithic horizon (Phase 1) yielded few characteristic artifacts, radiocarbon datings place it in the 7th millennium cal BC. In any case, an original aspect of the site is the key role played by marine resources throughout both its Mesolithic and Neolithic phases.

Evidence of 11-Hydroxy-hexahydrocannabinol and 11-Nor-9-carboxy-hexahydrocannabinol as Novel Human Metabolites of Δ9-Tetrahydrocannabinol.

(-)-trans-Δ9-tetrahydrocannabinol (Δ9-THC) is the primary psychoactive compound in the Cannabis sativa plant. Δ9-THC undergoes extensive metabolism, with the main human phase I metabolites being 11-hydroxy-tetrahydrocannabinol (11-OH-THC) and 11-nor-9-carboxy-tetrahydrocannabinol (THC-COOH). Early animal studies have indicated that the 9-10 double bond may be reduced in vivo to yield 11-hydroxy-hexahydrocannabinol (11-OH-HHC) and 11-nor-9-carboxy-hexahydrocannabinol (HHC-COOH). These metabolites have not been confirmed in humans. In this study, we aimed to investigate whether this metabolic transformation occurs in humans. A range of cannabinoids and metabolites, including 11-OH-HHC and HHC-COOH, were measured in whole blood from 308 authentic forensic traffic cases, of which 222 were positive for Δ9-THC. HHC-COOH and 11-OH-HHC were detected in 84% and 15% of the Δ9-THC positive cases, respectively, and the estimated median concentration of HHC-COOH was 7%, relative to that of THC-COOH. To corroborate the in vivo findings, Δ9-THC and its metabolites 11-OH-THC and THC-COOH were incubated with pooled human liver microsomes. HHC-COOH was detected in both the Δ9-THC and 11-OH-THC incubations, while 11-OH-HHC was only detectable in the 11-OH-THC incubation. Hexahydrocannabinol was not detected in any of the incubations, indicating that it is 11-OH-THC or the corresponding aldehyde that undergoes double bond reduction with subsequent oxidation of the aliphatic alcohol to HHC-COOH. In summary, the presented data provide the first evidence of HHC-COOH and 11-OH-HHC being human phase I metabolites of Δ9-THC. These findings have implications for interpretation of analytical results from subjects exposed to Δ9-THC or HHC.