Coupling redox flow desalination with lithium recovery from spent lithium-ion batteries.

Electrochemical redox flow desalination is an emerging method to obtain freshwater; however, the costly requirement for continuously supplying and regenerating redox species limits their practical applications. Recycling of spent lithium-ion batteries is a growing challenge for their sustainable utilization. Existing battery recycling methods often involve massive secondary pollution. Here, we demonstrate a redox flow system to couple redox flow desalination with lithium recovery from spent lithium-ion batteries. The spontaneous reaction between a battery cathode material (LiFePO4) and ferricyanide enables the continuous regeneration of the redox species required for desalination. Several critical operating parameters are optimized, including current density, the concentrations of redox species, salt concentrations of brine, and the amounts of added LiFePO4. With the addition of 0.5920 g of spent LiFePO4 in five consecutive batches, the system can operate over 24 h, achieving 70.46 % lithium recovery in the form of LiCl aqueous solution at the concentration of 6.716 g·L-1. Simultaneously, the brine (25 mL, 10000 ppm NaCl) was desalinated to freshwater. Detailed cost analysis shows that this redox flow system could generate a revenue of ¥ 13.66 per kg of processed spent lithium-ion batteries with low energy consumption (0.77 MJ kg-1) and few greenhouse gas emissions indicating excellent economic and environmental benefits over existing lithium-ion battery recycling technologies, such as pyrometallurgical and hydrometallurgical methods. This work opens a new approach to holistically addressing water and energy challenges to achieve sustainable development.

Research on High-Resolution Miniaturized MEMS Accelerometer Interface ASIC.

High-precision microelectromechanical system (MEMS) accelerometers have wide application in the military and civil fields. The closed-loop microaccelerometer interface circuit with switched capacitor topology has a high signal-to-noise ratio, wide bandwidth, good linearity, and easy implementation in complementary metal oxide semiconductor (CMOS) process. Aiming at the urgent need for high-precision MEMS accelerometers in geophones, we carried out relevant research on high-performance closed-loop application specific integrated circuit (ASIC) chips. According to the characteristics of the performance parameters and output signal of MEMS accelerometers used in geophones, a high-precision closed-loop interface ASIC chip based on electrostatic time-multiplexing feedback technology and proportion integration differentiation (PID) feedback control technology was designed and implemented. The interface circuit consisted of a low-noise charge-sensitive amplifier (CSA), a sampling and holding circuit, and a PID feedback circuit. We analyzed and optimized the noise characteristics of the interface circuit and used a capacitance compensation array method to eliminate misalignment of the sensitive element. The correlated double sampling (CDS) technology was used to eliminate low-frequency noise and offset of the interface circuit. The layout design and engineering batch chip were fabricated by a standard 0.35 µm CMOS process. The active area of the chip was 3.2 mm × 3 mm. We tested the performance of the accelerometer system with the following conditions: power dissipation of 7.7 mW with a 5 V power supply and noise density less than 0.5 µg/Hz1/2. The accelerometers had a sensitivity of 1.2 V/g and an input range of ±1.2 g. The nonlinearity was 0.15%, and the bias instability was about 50 µg.

Geosynchronous Satellite GF-4 Observations of Chlorophyll-a Distribution Details in the Bohai Sea, China.

We analyzed the distribution of chlorophyll-a (Chla) in the Bohai Sea area based on data from the geosynchronous orbit optical satellite Gaofen-4 (GF-4), which was launched in 2015, carrying a panchromatic multispectral sensor (PMS). This is the first time the geosynchronous orbit optical satellite GF-4 remote-sensing data has been used in China to detect the Chla change details in the Bohai Sea. A new GF-4 retrieved model was established based on the relationship between in situ Chla value and the reflectance combination of 2 and 4 bands, with the R2 of 0.9685 and the total average relative error of 37.42%. Twenty PMS images obtained from 2017 to 2019 were applied to analyze Chla in Bohai sea. The results show that: (1) the new built Chla inversion model PMS-1 for the GF-4 PMS sensor can extract Chla distribution details in the Bohai Sea well. The high Chla content in the Bohai Sea is mainly located in coastal areas, such as the top of Laizhou Bay, Bohai Bay and Liaodong Bay, with the value being around 13 µg/L. The concentration of Chla in the Bohai Strait and northern Yellow Sea is relatively low with the value being around 5 µg/L. (2). Taking full advantage of the continuous observation of geostationary orbit satellite, GF-4 with a high-resolution sensor PMS of 50 m can effectively detect short-term change (changes within 10 min) in Chla concentration. The changes mainly appear at the southwest and northeast costal area as well as in the center of Bohai Sea with the change value of around 3 µg/L. (3) The change of Chla concentration in the Bohai sea is related to the environmental factors such as seawater temperature, salinity, illumination and nutrient salts, as well as the dynamic factors such as wind, flow field and tidal current.

A case study of Chlorophyll a response to tropical cyclone Wind Pump considering Kuroshio invasion and air-sea heat exchange.

New evidences provided that the tropical cyclone (TC) Linfa in 2015 induced looping path of Kuroshio invasion into the northeastern South China Sea (NESCS) through the northwestern Luzon Strait (LS), based on the in-situ measurements, satellite data and model output data. This TC-enhanced Kuroshio invasion with low nutrients and denser waters suppressed the TC "Wind Pump" induced upwelling and nutrients uptake, and therefore inhibited the Chlorophyll a concentration (Chl-a) increase from surface to ~50 m in the open ocean of the NESCS. The TC-induced Kuroshio invasion promoted the generation of the strong cyclonic eddy to its left side where weak Ekman Pumping Velocity was observed. This enhancing cyclonic eddy then dominated the nutrients uplift and increased the surface and subsurface (0-50 m) Chl-a through eddy pumping rather than Ekman Pumping. The TC-declined anti-cyclonic eddy, which shoaled the Mixed Layer Depth (MLD), benefited to the nutrient uptake through TC-induced upwelling and thereby increased the surface Chl-a and raised the Chl-a Maximum Layer (CML) to ~20 m over the southwestern LS. The temporal Chl-a variations were also influenced by TC intensities and biochemical processes. The air-sea heat budget analysis indicated that, the air-sea heat exchange contributed to nearly 80% of the sea surface cooling (SST cooling) over the northwestern LS with Kuroshio invasion, while eddy-induced upwelling dominated the SST cooling over the western LS, and the wind-driven upwelling (and mixing) controlled the SST cooling over the southwestern LS. These different formations of SST cooling then played important role in Chl-a variations. This study is the first case of TC "Wind Pump" induced Chl-a variations considering air-sea heat exchange, Kuroshio invasion and mesoscale eddies over LS, which would help to evaluate the influence of TCs over the other major heat transport arteries of the world ocean: The Gulf Stream area.

Basin-wide responses of the South China Sea environment to Super Typhoon Mangkhut (2018).

Relative to the open Northwest Pacific, the basin-scale South China Sea (SCS) is smaller and semi-enclosed, and the impacts of frequent super typhoons on the entire SCS basin have yet to be fully understood. Using multi-satellite observations and reanalysis data, this study explored biophysical responses of the upper ocean of the SCS induced by a typical super typhoon, Mangkhut (2018), and their regional differences with potential mechanisms. There were three different significant-response regions in the whole SCS, as follows: (1) In the ocean area around the typhoon path, strong vertical mixing, upwelling and cooling were induced, resulting in the surface chlorophyll-a (chl-a) concentration enhancing markedly (three-fold). Particularly, asymmetric distribution of typhoon rainfall induced asymmetric sea surface salinity change over along the path the nearshore. Diurnal peak of chl-a concentration increased obviously, and the daily growth rate of chl-a sped up considerably in non-shore areas after Mangkhut's passage. (2) In the Beibu Gulf (BBG), the peripheral winds of Mangkhut caused a change in direction of the sea surface flow field, transporting the high-temperature and high-salinity surface seawater from the southeastern area to the BBG. This induced dramatic increases in sea surface temperature, salinity and height, and a decrease in chl-a, in most areas of BBG. (3) In the southwest SCS, the southwest monsoon-induced eastward offshore upwelling jet was weakened by the opposite large-scale peripheral wind vector of Mangkhut and gradually disappeared, resulting in accumulation and enhancement of chl-a in the nearshore. In addition, Mangkhut peripheral winds also intensified (weakened), shifting the cold (warm) eddy to the north (south) and blocking the horizontal eastward transport belt of the high-concentration chl-a. In general, our present work sheds light on the new evidence that a supper typhoon can cause basin-wide anomalies in the SCS, which has broad implications for marine biophysical environment.

Variation of pCO2 concentrations induced by tropical cyclones "Wind-Pump" in the middle-latitude surface oceans: A comparative study.

The Bermuda Testbed Mooring (BTM) and Bay of Bengal Ocean Acidification (BOBOA) mooring measurements were used to identify changes in the partial pressure of CO2 at the sea surface (pCO2sea) and air-sea CO2 fluxes (FCO2) associated with passage of two tropical cyclones (TCs), Florence and Hudhud. TC Florence passed about 165 km off the BTM mooring site with strong wind speeds of 24.8 m s-1 and translation speed of 7.23 m s-1. TC Hudhud passed about 178 km off the BOBOA mooring site with wind speeds of 14.0 m s-1 and translation speed of 2.58 m s-1. The present study examined the effect of temperature, salinity, dissolved inorganic carbon (DIC), total alkalinity (TA), air-sea CO2 flux, and phytoplankton chlorophyll a change on pCO2sea as a response to TCs. Enhanced mixed layer depths were observed due to TCs-induced vertical mixing at both mooring sites. Decreased pCO2sea (-15.16±5.60 µatm) at the BTM mooring site and enhanced pCO2sea (14.81±7.03 µatm) at the BOBOA mooring site were observed after the passage of Florence and Hudhud, respectively. Both DIC and TA are strongly correlated with salinity in the upper layer of the isothermal layer depth (ILD). Strong (weak) vertical gradient in salinity is accompanied by strong (weak) vertical gradients in DIC and TA. Strong vertical salinity gradient in the upper layer of the ILD (0.031 psu m-1), that supply much salinity, dissolved inorganic carbon and total alkalinity from the thermocline was the cause of the increased pCO2sea in the BOBOA mooring water. Weak vertical salinity gradient in the upper layer of the ILD (0.003 psu m-1) was responsible for decreasing pCO2sea in the BTM mooring water. The results of this study showed that the vertical salinity gradient in the upper layer of the ILD is a good indicator of the pCO2sea variation after the passages of TCs.

Variability in phytoplankton biomass and effects of sea surface temperature based on satellite data from the Yellow Sea, China.

A time series of satellite data on Chlorophyll-a concentration (Chl-a) that used ocean color was studied to determine mechanisms of phytoplankton variation in recent decade in the Yellow Sea, China during 2003-2015. The variability patterns on seasonal and inter-annual oscillation periods were confirmed using the Empirical Orthogonal Function (EOF), and Morlet wavelet transform analyses, respectively. The first EOF mode for Chl-a was dominated by obvious spring and fall blooms in a spatial pattern that was related to the strong mixing of the water masses from the Yellow Sea Cold Warm Mass (YSCWM) and the Yellow Sea Warm Current (YSWC) in winter. The second EOF mode for Chl-a showed an opposite spatial pattern between the northern and southern regions. The temporal coefficient showed differences in the timing of blooms. On an inter-annual scale, Chl-a indicated variation at periods of 2-4 years during 2003-2015. Chl-a showed a significantly negative correlation with the sea surface temperature (r = -0.21, p<0.01), with time lags of 4 months (Chl-a ahead). Chl-a was coupled with El Niño Southern Oscillation (ENSO) events, with a positive correlation (r = 0.46, p<0.01) at a lag of 3-5 months (ENSO ahead). The present study demonstrated that the variation in phytoplankton biomass was controlled primarily by water mass seasonally, and it was influenced by ENSO events on an inter-annual scale.

Dissolved oxygen responses to tropical cyclones "Wind Pump" on pre-existing cyclonic and anticyclonic eddies in the Bay of Bengal.

This study examines how dissolved oxygen (DO) responds to tropical cyclones (TCs) "Wind Pump" in a pre-existing cyclonic and an anticyclonic eddy over the Bay of Bengal (BoB) based on Argo and satellite data. Both TCs induced DO temporal decreases in the subsurface waters (Deep Depression BOB 04 with a pre-existing cyclonic eddy and cyclonic storm Roanu with a pre-existing anticyclonic eddy) owing mainly to the storm-induced upwelling. The deeper oxycline caused by the pre-existing anticyclonic eddy relieved the storm-induced shallow of oxycline during Roanu. On the contrary, the pre-existing cyclonic eddy shoaled the oxycline, intensifying the storm-induced shallow of oxycline during BOB 04. Furthermore, the pre-existing cyclonic eddy induced a long time of DO decrease after BOB 04. This study suggests that the subsurface DO concentrations in the BoB are affected mainly by storm-induced physical processes, and the mesoscale eddies also play an important role.

Study of dissolved oxygen responses to tropical cyclones in the Bay of Bengal based on Argo and satellite observations.

Effects of tropical cyclones (TCs) on dissolved oxygen (DO) in subsurface waters (20-200 m) over the Oxygen Minimum Zones (OMZs) in the Bay of Bengal (BoB) are examined based on Argo and satellite data. Five TCs (Hudhud, Five, Vardah, Maarutha and Mora) during 2013-2018 are considered. Analyses reveal three types of DO temporal variability caused by the storm-induced mixing and upwelling. The first type features temporal DO increases in subsurface waters (37-70 m) caused mainly by intense vertical mixing and downwelling. The second type features DO reductions in subsurface waters after the storms attributed to storm-induced upwelling. The third type features temporal DO increases at depths between 40 and 79 m and decreases at depths between 80 and 150 m due to the combined effect of strong vertical mixing and upwelling. These three types of DO responses can occur in different areas, depending on TC intensity, translational speed and Ekman pumping. The temporal DO variability is also influenced by the shallow oxycline (58.3 ±â€¯16.7 m), mesoscale eddies and biochemical processes. Due to TC intensification, a pre-existing oceanic cyclonic eddy produced a large upwelling and induced a long time of DO decrease in the subsurface layer. This study suggests three different types of DO responses along the TC track in the OMZ, which is useful to evaluate the influence of TCs on the OMZ.

Response of Sthenoteuthis oualaniensis to marine environmental changes in the north-central South China Sea based on satellite and in situ observations.

In the South China Sea (SCS), Sthenoteuthis oualaniensis (S. oualaniensis) generally has the highest stock density in spring and occupies an important position in fisheries. The responses of S. oualaniensis to marine environments in the north-central SCS in spring (March to May) from 2006 to 2010 were analyzed using satellite and in situ observations, with generalized additive models (GAMs). A high proportion variation in catch per unit effort (CPUE) was explained by environmental variables, including sea surface temperature (SST; explaining 13.8%) and the interaction between SST and chlorophyll a (Chl-a) concentration (explaining 16.9%). SSTs within the range of 24-28°C and Chl-a concentrations within 0.10-0.35 mg/m3 had positive effects on S. oualaniensis CPUE, and SST within 28-29.5°Cand Chl-a concentrations within 0.05-0.20 mg/m3 had negative effects. In addition, the response time of the maximum standardized catch per unit effort (SCPUE) in May to the maximum Chl-a in March was approximately six ten-day time step. The higher Chl-a and smaller stock size of S. oualaniensis in early March 2008 were partly associated with climatic anomalies caused by La Niña in spring and the limitation of S. oualaniensisby low temperature in 2008. The findings in this study can help better protect and manage S. oualaniensis resources in the SCS.

Evaluation Intravenous Drip Cephazolin Prophylaxis of Breast Cancer Surgery Site Infection.

PURPOSE: The efficacy of antibiotic prophylaxis for the prevention of surgical site infection (SSI) after breast cancer surgery remains uncertain. The authors of a recent Cochrane meta-analysis based on 15 randomized trials were unable to draw a definitive conclusion. The purpose of this study was to determine the effectiveness of prophylactic antibiotics for the prevention of SSI after breast cancer surgery and the risk factors for SSI. METHODS: Breast cancer patients who underwent mastectomy at the authors' institution were enrolled in this study. All the patients give cephazolin by intravenous drip within 1 hour before surgery. Surgical site infection was defined using Centers for Disease Control criteria. Risk factors were abstracted from the electronic medical record. Pearson χ test, Student t test, and multivariable logistic regression were used for the analysis. RESULTS: Four hundred fifty-eight patients undergoing mastectomy were enrolled in this study, including 293 with intravenous drip cephazolin and 165 without. Among them, an overall SSI rate of 6.1% was observed; 4.2% of patients without prophylactic antibiotics developed SSI compared with 7.2% with antibiotics (P = 0.210). Factors associated with SSI were hypertension, diabetes, length of stay (d), age, and length of stay. Weight, duration of surgery, No. of drains, surgical procedure, and type of breast disease were not associated with increased SSI rates. CONCLUSIONS: Surgical site infection rates among patients who did and did not receive cephazolin after mastectomy had no significantly different. What is more, the authors should focus on advanced age, hypertension, diabetes, length of stay, and length of stay to decrease development of postoperative SSI rates.

The effectiveness of i.v. cefuroxime prophylaxis of surgical site infection after elective inguinal hernia repair with mesh: A retrospective observational study.

PURPOSE: The efficacy of routine antibiotic prophylaxis for prevention of surgical site infection (SSI) after elective inguinal hernia repair with a mesh patch remains uncertain. The authors of a recent Cochrane meta-analysis based on 17 randomized trials were unable to draw a definitive conclusion on this subject. The purpose of this study was to determine the effectiveness of prophylactic antibiotics for prevention of SSI after elective inguinal hernia repair with mesh and the risk factors for SSI. METHODS: All low-risk patients who underwent elective inguinal hernia repair with mesh at our institution between 2010 and 2015 were enrolled in this study, with the exception of patients with recurrent hernias or immunosuppressive diseases. All patients received a single intravenous (i.v.) injection of cefuroxime (1.5 g) within 2 h prior to surgery at the discretion of the surgeon. SSI was defined using criteria of the Centers for Disease Control and Prevention. The variables which could influence the rate of SSI were analyzed by multivariate analysis to determine the independent risk factors for SSI. RESULTS: Among the 605 patients who underwent elective inguinal hernia repair with mesh during the study period, 553 were eligible for enrolment in the study. Of these, 331 received a single dose of cefuroxime preoperatively. The overall SSI rate was 5.4 %; 9.4 % of those patients who did not receive preoperative antibiotic prophylaxis developed SSI versus 2.8 % of those who did receive prophylaxis (P = 0.001). All infections were superficial. Factors independently associated with SSI were advanced age, smoking and preoperative stay. CONCLUSIONS: The incidence of SSI among low-risk patients who did and did not receive preoperative antibiotic prophylaxis after elective inguinal hernia repair with mesh differed significantly, particularly among patients of advanced age, smokers and patients with a prolonged preoperative stay in the hospital.

Isolation of high molecular weight DNA from marine sponge bacteria for BAC library construction.

Metagenomics is a powerful tool for mining the genetic repositories from environmental microorganisms. Bacteria associated with marine sponges (phylum Porifera) are rich sources of biologically active natural products. However, to date, few compounds are discovered from the sponge metagenomic libraries, and the main reason might be the difficulties in recovery of high molecular weight (HMW) DNA from sponge symbionts to construct large insert libraries. Here, we describe a method to recover HMW bacterial DNA from diverse sponges with high quality for bacterial artificial chromosome (BAC) library construction. Microorganisms concentrated from sponges by differential centrifugation were embedded in agarose plugs to lyse out the HMW DNA for recovery. DNA fragments over 436 kb size were recovered from three different types of sponges, Halichondria sp., Haliclona sp., and Xestospongia sp. To evaluate the recovered DNA quality, the diversity of bacterial DNA comprised in the HMW DNA derived from sponge Halichondria sp. was analyzed, and this HMW DNA sample was also cloned into a shuttle BAC vector between Escherichia coli and Streptomyces sp. The results showed that more than five types of bacterial DNA, i.e., Proteobacteria, Nitrospirae, Cyanobacteria, Planctomycetes, and unidentified bacteria, had been recovered by this method, and an average 100 kb size insert DNA in a constructed BAC library demonstrated that the recovered HMW DNA is suitable for metagenomic library construction.

The effects of wind and rainfall on suspended sediment concentration related to the 2004 Indian Ocean tsunami.

The effects of rainfall and wind speed on the dynamics of suspended sediment concentration (SSC), during the 2004 Indian Ocean tsunami, were analyzed using spatial statistical models. The results showed a positive effect of wind speed on SSC, and inconsistent effects (positive and negative) of rainfall on SSC. The effects of wind speed and rainfall on SSC weakened immediately around the tsunami, indicating tsunami-caused floods and earthquake-induced shaking may have suddenly disturbed the ocean-atmosphere interaction processes, and thus weakened the effects of wind speed and rainfall on SSC. Wind speed and rainfall increased markedly, and reached their maximum values immediately after the tsunami week. Rainfall at this particular week exceeded twice the average for the same period over the previous 4years. The tsunami-affected air-sea interactions may have increased both wind speed and rainfall immediately after the tsunami week, which directly lead to the variations in SSC.