Recharge Cycles Research Articles

Investigation of Silicon-Based Anodes for Li-Ion Batteries Using X-Rays and Neutron 3D/4D Imaging Techniques

Silicon-based anode materials are one of the most promising approaches to further increase the energy density of lithium-ion batteries. However, current materials are limited by poor cycling stability and rapid capacity fading, mainly caused by the massive volume expansion of Si during lithiation and subsequent strain on the material composite. [1] Furthermore, this electrode swelling also results in continuous solid electrolyte interface (SEI) growth, which hinders the migration of Lithium and leads to permanent capacity loss. [2] [3]To optimize these materials, analytical techniques able to probe the local 3D morphology and Li content are necessary. By applying methods such as neutron computed tomography (NCT), X-Ray computed tomography (XCT) and synchrotron scattering micro-tomography (SMT) structural ageing and changes in the distribution of lithium in the various components can be characterized and quantified for different charging states and recharge cycle numbers.This study investigates an anode material based on a dual phase alloy system of amorphous Silicon (a-Si) with crystalline iron silicide (c-FeSi2) and graphite. [4] [5] Li-ion battery coin cells containing this silicon-graphite composite anode material were industrially produced and aged by performing 1, 300, and 700 charge-discharge cycles, corresponding to remaining capacities of 100, 70 and 50 %, respectively. NCT and XCT scans were acquired at the NeXT instrument of the ILL in Grenoble (France) [6], and SMT measurements performed at ID31 of the neighboring ESRF. These datasets were reconstructed and evaluated using specially developed data processing pipelines. By performing multi-modal registration, the NCT and XCT scans were aligned and segmented to combine the complementary datasets and create a 4D model of the Li-ion battery coin cells.Figure 1 shows a sample of the combined NCT (cyan) and XCT datasets (red). Cropped horizontal slices of Li-Ion battery coin cells are depicted side by side with the main components labelled. Comparing one of the highly cycled cells with 50% remaining capacity (top) with the reference cell without electrolyte (bottom), trapped Lithium can be observed in the anode layers, visible as cyan colored blotchy areas in the otherwise dark component. The pixel size is approximately 5 µm.The change of lithium distribution in the components between different cycle numbers and charge states in the attenuation-based tomography techniques of NCT / XCT is quantified by modelling expected attenuation parameters to the observed values. The diffraction-based tomography method of SMT was modeled using expected lattice parameters. From this information, trapped Lithium can be identified and changes in the distribution are analyzed to point out possible degradation and failure mechanisms.We acknowledge financial support from the European Union’s Horizon 2020 research and Innovation program No. 875514 (ECO2LIB) as well as No. 847439 (InnovaXN) under the Marie Skłodowska-Curie grant agreement.[1] S. Tardif et al, https://doi.org/10.1021/acsnano.7b05796 [2] T. Vorauer et al, https://doi.org/10.1038/s42004-020-00386-x [3] P. Kumar et al, https://doi.org/10.1002/smll.201906812 [4] C. Berhaut et al, https://doi.org/10.1021/acsnano.9b05055 [5] C. Berhaut et al, https://doi.org/10.1016/j.ensm.2020.04.008 [6] A. Tengattini et al, https://doi.org/10.1016/j.nima.2020.163939 Figure 1

A Computational Method for Modeling Spatiotemporal Variability of Hydrodynamic Properties in Sandy Soil Under Drainage and Recharge

This article proposes an analytical strategy that combines X-ray Computed Tomography (CT) and Continuous Wavelet Transform (CWT) analysis as an alternative solution to long-term experiments that seek to investigate spatiotemporal variations in soil hydraulic properties induced by drainage and recharge cycles. We conducted CT scanning on 100-cm-high column filled with two types of sandy soil in a laboratory environment to simulate, over the period of a month, the equivalent of nearly 40 years of drainage/recharge cycles akin to agricultural fields adopting subirrigation as water management practices. We also monitored soil matric potential, water inflow and outflow, as well as movement of tracers. This later consists in zirconium oxide (ZrO2) that we added to the top 20 cm of each soil column. The results revealed that drainage and recharge cycles greatly affect the evolution of soil hydraulic properties at different locations along the soil profile by reducing drainage and capillary capacities. The approach also allowed us to identify each periodic component of drainage and recharge cycles, and thereby calculate the periodic drift over time. The proposed method can be applied to predict soil evolution according to soil texture, drainage system design and water management, thereby offering a potential basis for proposing mitigation measures related to soil hydrodynamics. It may find its application in agricultural farms adopting subirrigation and surface (e.g., drip) irrigation approaches and, in mining and civil engineering.

Extent and Volume of Lava Flows Erupted at 9°50′N, East Pacific Rise in 2005–2006 From Autonomous Underwater Vehicle Surveys

AbstractSeafloor volcanic eruptions are difficult to directly observe due to lengthy eruption cycles and the remote location of mid‐ocean ridges. Volcanic eruptions in 2005–2006 at 9°50′N on the East Pacific Rise have been well documented, but the lava volume and flow extent remain uncertain because of the limited near‐bottom bathymetric data. We present near‐bottom data collected during 19 autonomous underwater vehicle (AUV) Sentry dives at 9°50′N in 2018, 2019, and 2021. The resulting 1 m‐resolution bathymetric grid and 20 cm‐resolution sidescan sonar images cover 115 km2, and span the entire area of the 2005–2006 eruptions, including an 8 km2 pre‐eruption survey collected with AUV ABE in 2001. Pre‐ and post‐eruption surveys, combined with sidescan sonar images and seismo‐acoustic impulsive events recorded during the eruptions, are used to quantify the lava flow extent and to estimate changes in seafloor depth caused by lava emplacement. During the 2005–2006 eruptions, lava flowed up to ∼3 km away from the axial summit trough, covering an area of ∼20.8 km2; ∼50% larger than previously thought. Where pre‐ and post‐eruption surveys overlap, individual flow lobes can be resolved, confirming that lava thickness varies from ∼1 to 10 m, and increases with distance from eruptive fissures. The resulting lava volume estimate indicates that ∼57% of the melt extracted from the axial melt lens probably remained in the subsurface as dikes. These observations provide insights into recharge cycles in the subsurface magma system, and are a baseline for studying future eruptions at the 9°50′N area.

Solar bipolar cell facilitating carbon dioxide for efficient coproduction of electricity and syngas

Herein, a novel solar system is first reported for the efficient generation of syngas and electricity by feeding solar energy plus carbon dioxide into a solar bipolar cell. The solar bipolar cell, fully driven by solar energy, is a rechargeable cycle system to realize the highly efficient co-production of electricity and syngas. The solar bipolar cell consists of hydroxide molten Cell (Ⅰ) for hydrogen production and carbonate molten Cell (Ⅱ) for carbon monoxide production, simultaneously plus the a generation of rechargeable electricity. Due to the combined utilization of solar thermal and electric effect, the solar system can charged/recharged by the potential difference of the cyclic redox reaction. The system could store electric energy (Charge) and generate syngas under solar and then release electric energy (Discharge) and syngas during not input of solar energy. The charge-discharged processes could be operated circularly for a release of fuel. The results demonstrated that the solar bipolar cell presented an overall maximum Coulomb efficiency of 85% at 450/800 °C. This work provides a new route to design a system which combines the renewable energy with the undesirable carbon dioxide for the clean and pollution-free discharged products.

Inteligentno upravljanje energijom za mobilne manipulatore koji koriste mašinsko učenje

Integrated robotic systems combining manipulators with mobile robots provide outstanding improvement opportunities for semi-automatic assembly processes leveraged by Industry 4.0. Factory operations are released from the rigid layout constraints imposed by conventional fixed robots. Thus, they introduce new challenges in managing the recharge cycles as the energy consumption of mobile manipulators is not simply related to the travelled distance but to the overall tasks executed. Its estimation requires a systemic approach. In the proposed solution, an intelligent monitoring system is implemented on board. Data gathered online, and Key Performance Indicators (KPIs) calculated during the working tasks are exploited by Machine Learning (ML) to optimize energy recharging cycles. Although the development of an intelligent monitoring framework for a mobile manipulator was the original objective of the research, the monitoring system is exploited here for energy management only, leaving space for other future applications.

Novel rechargeable calcium fluoride dental nanocomposites

ObjectivesComposite restorations with calcium fluoride nanoparticles (nCaF2) can remineralize tooth structure through F and Ca ion release. However, the persistence of ion release is limited. The objectives for this study were to achieve long-term remineralization by developing a rechargeable nCaF2 nanocomposite and investigating the F and Ca recharge and re-release capabilities. MethodsThree nCaF2 nanocomposites were formulated: (1) BT-nCaF2:Bisphenol A glycidyl dimethacrylate (BisGMA) and triethylene glycol dimethacrylate (TEGDMA); (2) PE-nCaF2:Pyromellitic glycerol dimethacrylate (PMGDM) and ethoxylated bisphenol A dimethacrylate (EBPADMA); (3) BTM-nCaF2:BisGMA, TEGDMA, and Bis[2-(methacryloyloxy)ethyl] phosphate (Bis-MEP). All formulations contained 15% nCaF2 and 55% glass particles. Initial flexural strength and elastic modulus, F and Ca ion release, recharge and re-release were tested and compared to three commercial fluoride-containing materials. ResultsBT and BTM nCaF2 composites were 3–4 times stronger and had elastic modulus 2 times that of resin-modified glass ionomer controls. PE-nCaF2 had comparable strength to RMGIs. All nCaF2 composites had significant F and Ca ion release and ion rechargeability. In F and Ca recharging cycles, PE-nCaF2 had the highest ion recharging capability among nCaF2 groups, followed by BT-nCaF2 and BTM-nCaF2 (p < 0.05). For all recharge cycles, ion release maintained similar levels, demonstrating long-term ion release was possible. Furthermore, after the final recharge cycle, nCaF2 nanocomposites provided continuous ion release for 42 days without further recharge. SignificanceNovel nCaF2 rechargeable nanocomposites exhibited significant F and Ca ion release over multiple recharge cycles, demonstrating continuous long-term ion release. These nanocomposites are promising restorations with lasting remineralization potential.

Robotic Total Station Monitoring in High Alpine Paraglacial Environments: Challenges and Solutions from the Great Aletsch Region (Valais, Switzerland)

Investigating surface displacements in high alpine environments is often subject to challenges due to the difficult accessibility or harsh climatic conditions. Measurement systems have improved greatly in recent years regarding accuracy, range, or energy consumption. Continuously receiving high-precision, real-time monitoring data from a remote location can still support a better understanding of slope dynamics and risk. We present the design, construction, operation, and performance of a complex surface displacement monitoring system installed in the surroundings of the Great Aletsch Glacier in the Swiss Alps, based on two robotic total stations to continuously measure 3D displacements with high accuracies. In addition, GNSS stations are also considered in order to pass from a local to a geographic reference system, as well as to improve the measurement accuracy. The monitoring network is aimed at studying several types of deformation processes, i.e., (i) gravitationally driven and irreversible rockslide movements around the tongue of the Great Aletsch Glacier, (ii) reversible rock slope deformations caused by annual cycles of groundwater recharge and depletion, and (iii) small irreversible deformations of stable rock slopes resulting from progressive rock damage driven by glacier retreat and cyclic hydraulic and thermal loading. We describe the technical details of the monitoring system, which has been in operation successfully for 6 years, and discuss the system performance in terms of its robustness and accuracy.

Teknik Pengisian Ulang Baterai Alkaline Nonrecharable Bekas Untuk Memperpanjang Umur Pemakaian

Alkaline battery is one type of battery that is designed for single use. As a result, there is a lot of waste or alkaline battery waste. To reduce the impact of alkaline battery waste, it is deemed necessary to conserve batteries, namely by extending their service life, thereby delaying the battery to become waste. The easy way is to recharge the battery so that it can be used again. Although alkaline batteries are disposable batteries, from the characteristics of the electrochemical reactions it can be seen that the chemical reactions can be reversed so that there is a possibility that the batteries can be recharged. Some of the limitations in recharging include the condition of the battery, recharging strategy, the limit on the number of charging cycles and the capacity of the battery when it is recharged. This paper discusses the procedure for conserving used alkaline batteries to increase the use time and at the same time reduce the negative impact of battery waste on the environment. The stages of the battery charging experiment are: 1) detecting the quality of used alkaline batteries, 2) determining the proper way of recharging and 3) estimating the number of safe recharge cycles before being recycled. The experimental results show that: 1) the detection of rechargeable batteries can be carried out by the short initial charge method and checking whether there is an increase in battery capacity, 2) the combined method of constant voltage and constant current is the fastest and safest way to recharge alkaline batteries, 3) the average alkaline battery can be recharged up to 8 times.

Energy Storing Plant Stem with Cytocompatibility for Supercapacitor Electrode

AbstractEndowing natural biological objects, such as plants or their parts, with non‐native and targeted electroactivity is an appealing challenge in nano‐biotechnology, which if addressed will circumvent the biomass carbonization and promote the emission‐free transformation of raw bioresources for green energy. Here, a general concept to produce supercapacitor electrodes from plant stems is reported, which exhibit promising electroactivity and cytocompatibility. The core innovation is to apply a conformal electroactive coating onto the surfaces of hyperbranched channels of plant stem by interfacial self‐assembly. The electroactive plant stem can be employed as a functional supercapacitor electrode, the capacitance of which is up to 2.35 F. Furthermore, more than 98% cell viability is well maintained after the plant stem electrode is incubated with MCF‐7 cells for 72 h, and even after 100 discharge–recharge cycles, suggesting this plant stem electrode has excellent cytocompatibility and cycling stability. This energy storing plant stem gives rise to new opportunities for integrating natural bioresources with artificial electroactive nanomaterials for cytocompatible energy storage devices.

The annual cycle of terrestrial water storage anomalies in CMIP6 models evaluated against GRACE data

AbstractTerrestrial water storage anomaly (TWSA) is a critical component of the global water cycle where improved spatiotemporal dynamics would enhance exploration of weather and climate-linked processes. Thus, correctly simulating TWSA is essential not only for water-resource management but also for assessing feedbacks to climate through land-atmosphere interactions. Here we evaluate simulated TWSA from 25 climate models (from the Climate Model Intercomparison Project 6) through comparison with TWSA from GRACE satellite data (2003 – 2014) in 14 river basins globally and assess causes of discrepancies by examining precipitation (P), evapotranspiration (ET), and runoff (Roff) fluxes during recharge (increasing TWS) and discharge (decreasing TWS) cycles. Most models show consistent biases in seasonal amplitudes of TWS anomalies relative to GRACE output: higher modeled amplitudes in river basins in high northern latitudes, Parana, and Congo, and lower amplitudes in most mid-latitude basins and other tropical basins. This TWSA systematic bias also exists in the previous CMIP5 simulations. Models overestimate P compared to observed P datasets in 7 out of 14 basins, which increases (decreases) seasonal storage amplitude relative to GRACE in the recharge (discharge) cycle. Overestimation (underestimation) of runoff is another common contributing factor in the discharge phase that increases (decreases) TWSA amplitudes relative to GRACE in 5 river basins. The results provide a comprehensive assessment of the reliability of the simulated annual range in TWSA through comparison with GRACE data that can be used to guide future model development.

Synthesis of rod-like ternary Cu(Cd)-In-S and quaternary Cu-Cd-In-S by controlled ion exchange of MIL-68(In) derived indium sulfide for high energy-storage capacitor

A facial solvothermal method is developed to prepare rod-like MIL-68(In) derived In2S3. By partially ion exchange procedure, as prepared In2S3 (IS) is being used for the fabrication of copper doped indium sulfide (CIS), cadmium doped indium sulfide (CdIS), and finally Cd, Cu co-doped indium sulfide (CdCIS). These composites used as electrode materials for the cathode of supercapacitors (SCs). It is found that the IS, CIS, CdIS, and CdCIS exhibit capacitive performance with a specific capacitance and specific capacity as high as 162, 250.8, 286, and 402.4 F g-1 (22.5, 34.8, 39.7 and 55.8 mAh g-1), respectively at current density of 2 A g-1 in the three-electrode measurement. The CdCIS electrode material experiences a significant growth in its specific capacitance because of the synergistic effect of co-doping of Cd, Cu in the composite, which can decrease the electrical resistivity of the composite and facilitate the movement of electrons among the active components. Also, the asymmetric supercapacitor (ASC) was successfully assembled with CdCIS as cathode and activated carbon (AC) as anode electrodes which shows excellent capacitance for usable energy storage applications. The CdCIS//AC ASC device exhibited a power density of 400 W kg-1 and an energy density of 5.2 Wh kg-1. Even within an ultra-short charging time of 0.35 s, the CdCIS//AC ASC device shows a high-power density of 11.63 kW kg-1 at an energy density of 1 Wh kg-1 and has long-term cycling performance with preservation of 90.2% after 2000 recharge cycles, suggesting their potential for use in high-performance electrochemical capacitors.

Variation in rainfall patterns triggering debris flow in the initiation zone of the Ichino-sawa torrent, Ohya landslide, Japan

Rainfall patterns that trigger debris flows may vary depending on the amount of sediment storage in their initiation zones. However, the current literature did not fully explore the relationship between the rainfall patterns triggering debris flows and changes in sediment storage. In this study, we investigated the variation in rainfall patterns for debris-flow occurrences via field-based, four-year monitoring in a steep mountainous torrent (the Ichino-sawa torrent) in Japan. In this catchment, the sediment storage changes seasonally owing to the sediment discharge by debris flow from summer to fall and sediment recharge due to freeze–thaw cycles during winter. We found that the readily mobilized sediment was locally accumulated in response to rainfall above the 5-mm 10-min−1 threshold. Subsequent debris-flow surges caused the entrainment of the accumulated sediment, which led to their development and propagation. Accordingly, the rainfall patterns that triggered debris flow tended to include longer consecutive periods above the rainfall threshold compared with the rainfall patterns that did not trigger debris flow. However, the decrease in sediment storage due to previous debris-flow events reduced the period above the threshold required to trigger debris flows. Hence, the decrease in sediment storage during summer to fall seasons reduced the rainfall threshold for debris-flow occurrences. Conversely, after sediment recharge during the subsequent winter, a relatively long period above the rainfall threshold was again necessary for debris-flow occurrences. Therefore, the rainfall pattern that triggers debris flow varies in response to the cycle of sediment discharge and recharge.

Ion release and recharge from a fissure sealant containing amorphous calcium phosphate.

To assess- the release of calcium and phosphate ions from a fissure sealant containing amorphous calcium phosphate (ACP), and to determine the re-release capacity of these ions when charged with a solution containing casein phosphopeptide-amorphous calcium phosphate (CPP-ACP). Nine blocks of ACP resin-based sealant were prepared and immersed in three solutions at different pH (4.0, 5.5, 7.0), and calcium and phosphate ion release was measured with ion chromatography at 1, 3, 5, 7, 14, 21 and 28 days after immersion. Sixty days after immersion, each block was charged with CPP-ACP solution in three 7-day cycles to investigate the re-release of these ions, which was measured on days 1, 3, and 7. No difference was observed in initial calcium ion release at pH 4.0 and pH 5.5. At both values, ion release was significantly higher than at pH 7.0 (p<0.001). Initial phosphate release was significantly different among the three pH values (p<0.001). After re-charging the specimens, calcium ion re-release was greater than phosphate ion release. Initial ion release from ACP resin-based sealant was greatest at the lowest pH. Ion release decreased with time. As the number of recharge cycles increased, ion re-release also improved. Phosphate ion re-release required more recharge cycles than calcium ion re-release.

Seasonal variations of groundwater recharge in a small subtropical agroforestry watershed with horizontal sedimentary bedrock

Groundwater recharge supports sustainable development for drinking water and irrigated agriculture in vast areas worldwide. Human activities and climate change (e.g., uneven precipitation) have significantly impacted groundwater dynamics. A long term monitoring and sampling campaign was conducted for the major water bodies to investigate the evolution of groundwater and its capacity to support sustainable development in a subtropical agroforestry catchment in the middle of the Sichuan Basin with horizontal sedimentary bedrock (red beds), where seasonal droughts are notable. Major hydrochemical indicators, including δD and δ18O were measured to trace the water movement. The results showed that the chemical type of shallow groundwater was Ca•Mg-HCO3 or Ca-HCO3, which was mainly controlled by the weathering and hydrolysis of rocks. The interaction processes in the rainy season were stronger than those in the dry season. The isotopic signature in rainwater showed distinct seasonal pattern was strengthened by the local basin climate. The isotopic signals of groundwater responding to rainfall showed that recharge cycles of shallow groundwater in the rainy season lasted approximately 45–75 days. The optimized estimation based on mixing model and chloride ion balance (CMB) showed that the rainfall recharge ratio to shallow groundwater averaged about 27.83% (4.3%–58.0%) at event scale and the annual rainfall recharge ratios averaged about 19.36% (12.2%–45.7%). Groundwater in this region was renewed rapidly, as its groundwater storage capacity could be low with horizontal sedimentary bedrock. By revealing the water chemistry dynamics of shallow groundwater in the study area, this work preliminarily identified the groundwater recharge sources and estimated the recharge ratios by rainfall in a typical hilly area with red beds, thus providing a scientific basis for further regional assessment of groundwater resources.

Groundwater recharge processes in an Asian mega-delta: hydrometric evidence from Bangladesh

Groundwater is used intensively in Asian mega-deltas yet the processes by which groundwater is replenished in these deltaic systems remain inadequately understood. Drawing insight from hourly monitoring of groundwater levels and rainfall in two contrasting settings, comprising permeable surficial deposits of Holocene age and Plio-Pleistocene terrace deposits, together with longer-term, lower-frequency records of groundwater levels, river stage, and rainfall from the Bengal Basin, conceptual models of recharge processes in these two depositional environments are developed. The representivity of these conceptual models across the Bengal Basin in Bangladesh is explored by way of statistical cluster analysis of groundwater-level time series data. Observational records reveal that both diffuse and focused recharge processes occur in Holocene deposits, whereas recharge in Plio-Pleistocene deposits is dominated by indirect leakage from river channels where incision has enabled a direct hydraulic connection between river channels and the Plio-Pleistocene aquifer underlying surficial clays. Seasonal cycles of recharge and discharge including the onset of dry-season groundwater-fed irrigation are well characterised by compiled observational records. Groundwater depletion, evident from declining groundwater levels with a diminished seasonality, is pronounced in Plio-Pleistocene environments where direct recharge is inhibited by the surficial clays. In contrast, intensive shallow groundwater abstraction in Holocene environments can enhance direct and indirect recharge via a more permeable surface geology. The vital contributions of indirect recharge of shallow groundwater identified in both depositional settings in the Bengal Basin highlight the critical limitation of using models that exclude this process in the estimation of groundwater recharge in Asian mega-deltas.

Nowcasting Earthquakes in Southern California With Machine Learning: Bursts, Swarms, and Aftershocks May Be Related to Levels of Regional Tectonic Stress

AbstractSeismic bursts in Southern California are sequences of small earthquakes strongly clustered in space and time and include seismic swarms and aftershock sequences. A readily observable property of these events, the radius of gyration (RG), allows us to connect the bursts to the temporal occurrence of the largest M ≥ 7 earthquakes in California since 1984. In the Southern California earthquake catalog, we identify hundreds of these potentially coherent space‐time structures in a region defined by a circle of radius 600 km around Los Angeles. We compute RG for each cluster then filter them to identify those bursts with large numbers of events closely clustered in space, which we call “compact” bursts. Our basic assumption is that these compact bursts reflect the dynamics associated with large earthquakes. Once we have filtered the burst catalog, we apply an exponential moving average to construct a time series for the Southern California region. We observe that the RG of these bursts systematically decreases prior to large earthquakes, in a process that we might term “radial localization.” The RG then rapidly increases during an aftershock sequence, and a new cycle of “radial localization” then begins. These time series display cycles of recharge and discharge reminiscent of seismic stress accumulation and release in the elastic rebound process. The complex burst dynamics we observe are evidently a property of the region as a whole, rather than being associated with individual faults. This new method allows us to improve earthquake nowcasting, which is a technique to evaluate the current state of hazard in a seismically active region.

A Framework for Optimization of Power Consumption in Mobile Computing Devices

Battery driven computing devices such as laptops and cellular phones have become a necessity in this era. Mobile applications help us in daily life activities and with the rise of Internet of Things (IoT) new opportunities are open up to automate different task. However, batteries have their own limitations such as weight, cost, and size. Multiple applications and background processes running in parallel easily drain phone’s battery within 24 hours consequently annoying users by limited battery capacity. Repeated charge, recharge cycles steadily diminish the full capacity of batteries resulting in the immense decreased performance of the device. Therefore, mobile devices and mobile applications are in great need of energy-aware modules. In this paper, a survey is performed to identify the needs of the mobile user in the context of energy consumption problem. The results of survey lead authors to propose a middle layer energy aware framework to address this issue. The proposed framework highly relies on the association between the operating system, application, and end user. The main objective of the proposed framework is to maintain an energy-aware capability to facilitate end user and mobile applications. The major components of the proposed framework are processing engine, application classifier, application resource management, system profiling, application modes, power estimator and power policy management. Proposed framework also offers a policy manager algorithm based on research community feedback and survey's results. Proposed framework emphasizes on energy efficient execution of mobile operations for end user and operating systems.

Three-dimensional fully coupled study of groundwater seepage and soil deformation under the action of cyclic pumping and recharge

Abstract. This study was undertaken in order to accurately analyze the land subsidence that is caused by the change in the seepage and stress fields during the pumping and recharge of groundwater. Based on Biot's consolidation theory and groundwater seepage theory (combined with theory regarding the nonlinear rheology of soil), the constitutive relationship of soil was extended to viscoelastic plastic; concurrently, considering the dynamic changes in hydraulic parameters and soil mechanical parameters, a three-dimensional fully coupled model of groundwater seepage and soil deformation was established. Using the groundwater recycling pumping and recharge test conducted by Land Subsidence Monitoring and Early Warning Center in Cangzhou City as an example, the site was divided into four loose porous aquifers. A constantly circulating pumping–recharge flow was simulated numerically, and numerical simulation was carried out on the third and fourth confined aquifers. The influence of groundwater seepage on soil deformation was analyzed, and the variation in hydraulic parameters and soil mechanical parameters were studied under the influence of the abovementioned cyclic pumping and recharge. The results show that soil deformation lags behind the change in the groundwater level, and that permanent residual deformation of soil is produced by water level fluctuations during groundwater pumping–recharge cycles. The effective porosity, the permeability coefficient and the Poisson ratio are positively correlated with the water level fluctuation in groundwater pumping–recharge cycles, whereas the modulus of deformation is negatively correlated with the water level fluctuation in groundwater during this process. All parameters change, and this change is permanent. The simulated results are in good agreement with the measured values.

Novel antibacterial calcium phosphate nanocomposite with long-term ion recharge and re-release to inhibit caries.

Short-term studies on calcium-phosphate (CaP) ion-rechargeable composites were reported. The long-term rechargeability is important but unknown. The objectives of this study were to investigate nanocomposite with strong antibacterial and ion-recharge capabilities containing dimethylaminododecyl methacrylate (DMAHDM) and nanoparticles of amorphous calcium phosphate (NACP), and evaluate long-term ion-recharge by testing for 12 cycles (taking 6 months to complete) for the first time. Three groups were tested: (1) Heliomolar control; (2) Resin+20%NACP+50%glass; (3) Resin+3%DMAHDM+20%NACP+50%glass. Biofilm acid and colony-forming units (CFU) were measured. Ion-recharge was tested for 12 cycles. NACP-DMAHDM composite reduced biofilm acid, and reduced CFU by 4 logs. High levels of ion releases were maintained throughout 12 cycles of recharge, maintaining steady-state releases without reduction in 6 months (p>0.1), representing long-term remineralization potential. Bioactive nanocomposite demonstrated long-term ion-rechargeability for the first time, showed remineralization and potent anti-biofilm functions, with promise for tooth restorations to combat caries.

AC Loss Analysis on Coated Conductors at different Sinusoidal Frequencies for Electric Propulsion Applications

Superconducting magnets are one of the superior contenders in achieving the targets of electric aircraft industry successfully as they have very high power densities compared to other battery storage systems. Many aviation research agencies are looking at superconducting magnets as one of the alternate in replacing the conventional jet engines completely (electric aircrafts) or partially (hybrid aircrafts). National Aeronautics and Space Administration (NASA) and Air Force Research Laboratory (AFRL), USA has reported that high temperature superconducting magnets possesses higher specific energies (Wh/kg) and have infinite number of recharge cycles compared to other storage technologies employed for energy requirements. The other advantage of using such magnets is that there will be no hazardous disposals like batteries which lower the overall pollution. Superconducting magnets are DC operated systems however during charging or discharging transient behaviour of current results in the losses which would further ends up with heat generation. Heat generation during charging or discharging period would cause quenching of the superconductor due to sudden temperature rise.In this work, electromagnetic analysis on superconducting magnet having capacity of 1 MJ has been performed where a 2D numerical model is developed using H-formulations in order to estimate the AC losses for a high temperature superconducting tape manufactured by SuperPower (SCS 12050) having 330 A critical current at 77 K. AC current having different load factors has been fed through the stacked tapes at 50 Hz, 60 Hz and 70 Hz frequency and AC losses have been evaluated. It has been found that at higher frequencies the AC losses are found to be larger than lower frequencies. Overcritical currents have been found in the current density distribution due to the application of E-J relationship for the homogeneous 2D numerical model.