Can Anthropization Govern the Variation in Water Table Levels, Water Flow and Carbon Losses? A Case Study in Tropical Mountain Peatlands an Serra Do Espinhaço Meridional, Minas Gerais, Brazil.

Peatlands are ecosystems formed by organic matter (~ 15% of the total mass) and water (~ 85% of the total mass), and constitute a particular type of free aquifer. They perform important hydrological functions by storing excess water during rainfall events, contributing to the baseflow of its rivers throughout the year. Degradation affects the dynamics of the water table, which, in turn, can influence the decomposition of organic matter content and the release of carbon into its waters. Its water retention capacity may also be compromised and reduce the volume of water available downstream, especially in the dry season. The aim of this study was to evaluate the effects of anthropic interference on variations in groundwater, water storage, and carbon flow in two tropical mountain peatlands, located at the head of the Araçuaí River, in Serra do Espinhaço Meridional (SdEM), Minas Gerais, Brazil. Groundwater levels were installed in piezometers distributed on a peatland located in a protected area (Natural Park) (Protected - TP) and in a peatland located outside the conservation unit (Anthropized - TA). Data were analyzed considering the daily rainfall recorded by an automatic weather station installed in the study area. From the data on precipitation and water table level variation, the specific yield (Sy) in the two peatlands was calculated. The observed flows and the mean monthly Sy on each piezometer were correlated and their significance was verified using the t test (p <0.05). The relationship between the observed flow and the mean monthly values of Sy obtained for the piezometers were verified through multiple regression. The specific yield correlated significantly with flow in both peatlands (p < 0.05). Multiple linear regression showed a coefficient of determination (R2) of 0.92 in both peatlands, indicating a direct relationship between Sy and observed flow. The TP presented a 43% smaller variation in the water table, a 7% higher specific yield and a specific flow rate of 13% higher in relation to the TA. The peatland located in a protected area retains more water, with less variation in flow throughout the year, and has less carbon output in the water compared to the anthropized peatland. The results demonstrated that anthropization is causing degradation of the peatland, reducing its water holding capacity and accelerating its carbon losses. In the medium term, these effects may lead to a drastic reduction in flow in the upper course of the Araçuaí River.

Microstructure and Mechanical Properties of Novel Lightweight TaNbVTi-Based Refractory High Entropy Alloys

A series of novel lightweight TaNbVTi-based refractory high entropy alloys (RHEA) were fabricated through ball-milling and spark plasma sintering (SPS). The reinforced phase of TiO precipitates were in-situ formed due to the introduction of Al2O3 ceramic particles. The RHEA with 15% Al2O3 exhibits a high compressive yield strength (1837 MPa) and a low density (7.75 g/cm3) with an adequate ductility retention. The yield strength and density are 32% higher and 15% lower, respectively, compared to the RHEA without Al2O3 addition. The specific yield strength (237 MPa cm3/g) of the RHEAs is much higher than that of other reported RHEAs, and is mainly ascribed to the introduction of high volume fraction of Al2O3 additives, resulting in solid solution strengthening and precipitation strengthening. Meanwhile, the ductile matrix is responsible for the good compressive plasticity.

Hydrologic changes of in-situ gravimetry

Inter-seasonal and geodynamics-related gravity changes are important geoscientific signals that are extractable from gravimeter observations after deducing background information as local hydrology gravity effect. With two superconducting gravimeters (SGs, OSG-053 and iGrav-007) located in different tectonic units, continuous Global Navigation Satellite System data, and AG observations, Wuhan (China) is an ideal location for investigating the effects of gravity resulting from significant local hydrology mass variations. We processed ∼26 months of gravity data collected from the SGs in Wuhan and obtain residuals of -40 nm.s2 for OSG-053 and 100 for iGrav-007. The hydrological observations show an estimated gravity increase of 42 nm.s2 near iGrav-007, which mainly resulted from the increased unconfined water level with an aquifer-specific yield of approximately 0.1. However, the gravity changes around OSG-053 are mainly from soil moisture and reach -90 nm.s2. The soil type, thickness and water content parameters were obtained from hydrogeological survey and drilling data. The deep confined water level rose by 2.5 m, which introduced a 1 nm.s2 gravity variation with a specific storage about 0.00001 from field unsteady flow pumping test. The modeled gravity is approximately -40 nm.s2 around OSG-053 and 90 around iGrav-007, in accordance with the observed gravity variations. The difference in gravity changes between the two SG observations can be explained by different local water storage environments. Our results suggest that unconfined and soil water significantly impact the in-situ gravimetry, which indicates that further detailed hydrogeological surveys are required. A combined investigation of gravity and water levels can be a useful approach to monitor aquifer storage conditions and groundwater management.

Modeling of Groundwater Potential Using Cloud Computing Platform: A Case Study from Nineveh Plain, Northern Iraq

Knowledge of the groundwater potential, especially in an arid region, can play a major role in planning the sustainable management of groundwater resources. In this study, nine machine learning (ML) algorithms—namely, Artificial Neural Network (ANN), Decision Jungle (DJ), Averaged Perceptron (AP), Bayes Point Machine (BPM), Decision Forest (DF), Locally-Deep Support Vector Machine (LD-SVM), Boosted Decision Tree (BDT), Logistic Regression (LG), and Support Vector Machine (SVM)—were run on the Microsoft Azure cloud computing platform to model the groundwater potential. We investigated the relationship between 512 operating boreholes with a specified specific capacity and 14 groundwater-influencing occurrence factors. The unconfined aquifer in the Nineveh plain, Mosul Governorate, northern Iraq, was used as a case study. The groundwater-influencing factors used included elevation, slope, curvature, topographic wetness index, stream power index, soil, land use/land cover (LULC), geology, drainage density, aquifer saturated thickness, aquifer hydraulic conductivity, aquifer specific yield, depth to groundwater, distance to faults, and fault density. Analysis of the contribution of these factors in groundwater potential using information gain ratio indicated that aquifer saturated thickness, rainfall, hydraulic conductivity, depth to groundwater, specific yield, and elevation were the most important factors (average merit > 0.1), followed by geology, fault density, drainage density, soil, LULC, and distance to faults (average merit < 0.1). The average merits for the remaining factors were zero, and thus, these factors were removed from the analysis. When the selected ML classifiers were used to estimate groundwater potential in the Azure cloud computing environment, the DJ and BDT models performed the best in terms of all statistical error measures used (accuracy, precision, recall, F-score, and area under the receiver operating characteristics curve), followed by DF and LD-SVM. The probability of groundwater potential from these algorithms was mapped and visualized into five groundwater potential zones: very low, low, moderate, high, and very high, which correspond to the northern (very low to low), southern (moderate), and middle (high to very high) portions of the study area. Using a cloud computing service provides an improved platform for quickly and cheaply running and testing different algorithms for predicting groundwater potential.

Development from Alloys to Nanocomposite for an Enhanced Mechanical and Ignition Response in Magnesium

The current study reports on the evolution of microstructure, variations in compressive properties and the ignition resistance of Mg through compositional variation, using alloying elements and nanoreinforcement. The alloys were designed with the use of a singular alloying element, Ca, and a binary alloying element, Ca+Sc, to develop Mg1Ca (wt.%) and Mg1Ca1Sc (wt.%) alloys. B4C nanoparticles were addedas the reinforcement phase in the Mg1Ca1Sc alloy to create the Mg1Ca1Sc/1.5B4C (wt.%) nanocomposite. The most effective compressive properties and level of ignition resistance was displayed by the developed composite. The grain sizes were significantly reduced in the Mg alloys (81%) and the composite (92%), compared with that of the Mg. Overall, the microstructural features (i.e., grain refinement, the formation of favorable intermetallic compounds, and hard reinforcement particles with an adequate distribution pattern) enhanced both the compressive strength and strain of the alloys and the composite. The ignition resistance was progressively increased from the alloys to the nanocomposite, and a peak ignition temperature of 752 °C was achieved in the composite. When compared with the ignition resistant of Elektron 21 (E21) alloy, which met the Federal Aviation Administration (FAA) requirements, the Mg1Ca1Sc/1.5B4C nanocomposite showed a higher specific yield strength and better ignition resistance, asserting it as a potential candidate material for lightweight engineering applications, including aerospace and defense sectors.

Bioenergetics’ potential of the poultry and swine wastes in Belgorod region of Russia

Studies of biogas productivity of broiler chicken manure and fattening pig manure collected at the enterprises of Belgorod region of Russia were carried out. The specific yield of biogas from broiler chicken manure was 0,449±0,014 m3/kg of organic matter (oDM), methane specific yield – 0,256±0,008 m3/kg of oDM, from pig manure – 0,300±0,006 and 0,185±0,005 m3/kg oDM, respectively. The annual yield of these substrates in the region was calculated. The energy potential of substrates conversion into biogas was determined: the total yield of electric energy will be 9.339 billion kWh, heat energy - 10.322 billion kWh per year, or 25.585 and 28.279 million kWh per day, respectively.

Water table variations on different land use units in a drained tropical peatland island of Indonesia

Restoration and water table control on peatlands to limit fire risk are national priorities in Indonesia. The present study was initiated at Padang Island, Sumatra, to increase understanding on peatland hydrology in the tropic. At the pilot site, water table and precipitation were monitored at different stations. The results show variation in water table depths (WTDs) over time and space due to spatial and temporal variability in rain intensity and drainage networks. In part of the island, large-scale drainage for plantations led to deep WTD (−1.8 m) and high WTD recession rates (up to 3.5 cm/day). Around villages, farm-scale drainages had a smaller impact with a lower recession rate (up to 1.8 cm/day) and shallow WTD, typically below −0.4 m, the threshold for sustainable peatland management in Indonesia. The recession rates levelled off at 1.0 cm/day near the drained forest/plantation and at 0.5 cm/day near the farm. Deeper layers had much lower specific yield (Sy), 0.1 at −1.5 m depth, compared with top peat soils with Sy up to 0.3. Proximity to drainages extended discharge flow to deeper layers. The results highlighted the severity of peatland drainage impact on most coastal zones of Padang Island, which have intensive drainage networks.