Mechanism of Silver Nanoparticles Deposition by Electrolysis and Electroless Methods on a Graphite Substrate

This study shows a silver electrodeposition model (EDM) on a graphite ‎substrate. The electrolyte was a 0.01 M solution of pure silver and chromium nitrate using an ‎electrolyzing cell. EDC with current density up to 20 mA/cm2 and 15 mV and pulse current were studied. Results revealed that silver deposited at a ‎rate of 0.515 mg/cm2/min with 12 mA /cm2 that decreases to 0.21 and 0.16 mg/cm2.min ‎with the decrease of current density to 6 and 5 mA/cm2 respectively. The model postulates that ‎silver ions (a) were first hydrated before diffusing (b) from the solution bulk to ‎the cathode vicinity, the next step (c) involved the chemical adsorption of these ions on certain ‎accessible sites of the graphite substrate (anode), the discharged entities (d) adhere to the graphite ‎surface by Van der Vales force. Silver ions are deposited because the ‎discharge potential of silver is low (0.38 mV) as compared to other metal ions like chromium (0.82 mV). Pulse ‎current controls silver deposition due to flexibility in controlling steps (a) - (c) of the ‎deposition mechanisms.

Combined Approaches to Predict Microplastic Emissions Within an Urbanized Estuary (Warnow, Southwestern Baltic Sea)

Microplastic river emissions are known to be one of the major sources for marine microplastic pollution. Especially urbanized estuaries localized at the land-sea interface and subjected to microplastic emissions from various sources exhibit a high microplastic discharge potential to adjacent coasts. To adapt effective measures against microplastic emissions a more detailed knowledge on the importance of various microplastic sources is necessary. As field data is scarce we combined different approaches to assess microplastic emissions into the Warnow estuary, southwestern Baltic Sea. Resulting microplastic emission estimates are based on in-situ measurements for the catchment emissions, whereas for the remaining microplastic sources within the estuary literature data on microplastic abundances, and various parameters were used (e.g. demographical, hydrological, geographical). The evaluation of the different emission scenarios revealed that the majority of microplastic is likely discharged by the Warnow river catchment (49.4%) and the separated city stormwater system (43.1%) into the estuary, followed by combined sewer discharges (6.1%). Wastewater treatment plant emissions exhibit the lowest percentage (1.4%). Our approach to estimate anti-fouling paint particles emissions from leisure and commercial shipping activities was associated with highest uncertainties. However, our results indicate the importance of this source highlighting the necessity for future research on the topic. Based on our assumptions for microplastic retention within the estuary, we estimate a potential annual emission of 152–291 billion microplastics (majority within the size class 10–100 µm) to the Baltic Sea. Considering all uncertainties of the different applied approaches, we could assess the importance of various microplastic sources which can be used by authorities to prioritize and establish emission reduction measures. Additionally, the study provides parameters for microplastic emission estimates that can be transferred from our model system to other urbanized Baltic estuaries.

A facile freeze-thaw ultrasonic assisted circulation method of graphite flakes prepared by anode graphite from spent lithium-ion batteries for application in nanofluids

Graphite has been widely used as the anode material in lithium-ion batteries (LIBs) due to its good conductivity, layered crystal structure, high charging-discharge potential, and other characteristics. With the rapid...

Enveloping Si/N-doped carbon composite in CNTs reinforced fibrous network as flexible anodes for high performance lithium ion batteries

Due to its highest theoretical capacity and low discharge potential, silicon (Si) is attracting an increasing attention as one of the most promising anodes for lithium ion batteries. However, the...

Microstructure and Discharge Performance of Aluminum Al 6061 Alloy as Anode for Electrolyte Activated Battery

Electrolyte activated battery finds its important use during natural disaster emergencies, such as floods and typhoons. Nevertheless, high corrosion rate will deteriorate the discharge performance of the battery and it is influenced by the type of electrolyte and discharge current. In this study, the corrosion and discharge performance of a commercial Al 6061 aluminum alloy as an anode are investigated at different discharge currents (0.001, 0.01, and 1 mA) and in different electrolytes, namely salt water, urea, and distilled water. Scanning electron microscopy results show that electrode in salt water has the most serious corrosion, followed by that of in urea and in distilled water. These electrode-electrolyte combinations are further investigated with potentiodynamic polarization, galvanostatic discharge, and electrochemical impedance spectroscopy (EIS) to understand their discharge potential, discharge behavior, and corrosion mechanism. Among all combinations, aluminum in water is found to have the highest discharge performance with discharge potentials ranging from 716 to 744 mV, regardless of discharge current.

Microstructure and Discharge Performance of Aluminum Al 6061 Alloy as Anode for Electrolyte Activated Battery

Electrolyte activated battery finds its important use during natural disaster emergencies, such as floods and typhoons. Nevertheless, high corrosion rate will deteriorate the discharge performance of the battery and it is influenced by the type of electrolyte and discharge current. In this study, the corrosion and discharge performance of a commercial Al 6061 aluminum alloy as an anode are investigated at different discharge currents (0.001, 0.01, and 1 mA) and in different electrolytes, namely salt water, urea, and distilled water. Scanning electron microscopy results show that electrode in salt water has the most serious corrosion, followed by that of in urea and in distilled water. These electrode-electrolyte combinations are further investigated with potentiodynamic polarization, galvanostatic discharge, and electrochemical impedance spectroscopy (EIS) to understand their discharge potential, discharge behavior, and corrosion mechanism. Among all combinations, aluminum in water is found to have the highest discharge performance with discharge potentials ranging from 716 to 744 mV, regardless of discharge current.

Delay in Hospital Discharge of Trauma Patients: A Prospective Observational Study

Background: "Delayed discharge" is defined as patients who remain hospitalized beyond the time of being fit for discharge. There is no standardized amount of time defining delayed discharge documented in the literature, and there is a lack of evidence about this topic in Egypt. This study aims to identify the factors associated with discharge delays.Methods: A prospective observational study included all trauma patients admitted to a University Hospital in Egypt over two months. The time of the decision of discharge and actual discharge time were recorded by reviewing patients' medical records. The patients and their caregivers were asked to fill in a questionnaire about the reasons for delayed discharge. Potential reasons for the delayed discharge were classified into system-related, medical and family-related factors. Results: The study included 498 patients with a median age of 41 years (9 – 72). The median time until the actual discharge was three hours. System-related factors were documented in 48.8% of cases, followed by medical factors (36.3%), and family-related factors (28.1%). When controlling for age, gender and injury severity score using a logistic regression analysis, longer time to discharge (≥ 3 hours) showed a stronger association with medical factors [adjusted OR (95% CI) = 5.44 (2.73-10.85)] and family-related factors [adjusted OR (95% CI) = 7.94 (3.40-18.54)] compared to system-related factors [adjusted OR (95% CI) = 2.20 (1.12-4.29)].Conclusion: Although system-related factors were more prevalent, medical and family-related factors appear to be associated with longer discharge delays compared to system-related factors.

Single atom dispersion of silicon as advanced versatile electrode material

Silicon (Si) exhibits highest theoretical charge capacity and low discharge potential, but the associated volume expansion cannot be neglected. Here we report a single atom dispersion strategy to prepare a well distributed Si single atom based electrode material, which can effectively inhibit the volume expansion even when the storage sites are fully occupied. The dispersion of Si single atoms are achieved by bonding Si atom with acetylenic carbon atom, forming a three-dimensional diamond-like skeleton. Owing to the combination of Si and diyne in the stable diamond-like skeleton, the as-prepared material, named as silicon-diamondyne (Si-DY), exhibits extraordinary electrochemical performance. Si-DY has been predicted to exhibit ultrahigh theoretical specific capacity of 3674 mA h g-1, 2810 mA h g-1, and 1945 mA h g-1 in lithium-ion battery (LIB), sodium-ion battery (SIB) and potassium-ion battery (KIB), respectively. Especially, the as-prepared Si-DY samples also achieve very stable measured specific capacity in LIB (2350 mA h g−1), SIB (812 mA h g-1) and KIB (512 mA h g-1), as well as ultra-long cycling stability (up to 5000 charge/discharge cycles). Those excellent results demonstrate the single atom dispersion technology of Si atoms can be an efficient way to prepare high-utilization Si based electrochemical materials.

Landscape-permafrost conditions and factors of summer runoff formation of small coastal lowland rivers

River feed and flow regime in the Anadyr lowland remain stable with significant interannual fluctuations in the amount of summer precipitation (70-180 mm). The lack of summer precipitation is compensated by the suprapermafrost groundwater of the active layer, which is formed by meltwater from seasonal underground ice. In July 2019, complex permafrost-hydrological studies were conducted in the Ugolnaya-Dionisia river basin (Chukotka, Russia) to determine the patterns of formation and dynamics of underground and surface runoff. Seasonal active layer groundwater storage that formed as a result of the melting of seasonal ice was estimated. The territory was classified according to the unite discharge, potential and established water sources. Patterns and factors of seasonal and daily dynamics of the river regime are revealed.