Days Of Operation Research Articles

Managing water gate operation and fish passage facilities in irrigated systems of the Nam Kam River, Thailand

AbstractThe migration of fishes through the Thoranit Naruemit water gate on the Nam Kam River, a tributary of the Mekong River in Thailand, was studied to understand the hydrological factors and improve the operational regime of the fish pass at the structure. Migration of fish from the Mekong River started in May, at the onset of the rainy season. During 60 days of operation, the fish pass supported the upstream migration of 83 species and ~440,000 fish, equivalent to about 11 tonnes of fish. The fish pass supported migration of a range of fish sizes between 45 and 700 mm, and most fish were larger than the size of first maturity for the species in question. The factors influencing migration into the Nam Kam included the lunar cycle, flow in the fish pass, water level in the river and flow variability. Migration tended to increase in the 3–4‐day period before or after a full moon. Discharge and water level changes associated with rising water levels in the Mekong River synchronize with the spawning season of most Mekong fish and trigger upstream migration. Many fish migrated through the pass at discharges through sluice gates between 8 and 323 m3/s and with a flow through the fish pass between 0.95 and 3.08 m/s. Restrictions to fish migration were found and recommendations for water gate and fish pass operation are provided.

Preoperative COVID-19 Vaccination is Associated with Decreased Perioperative Mortality after Major Vascular Surgery.

The objective of this study was to examine the effect of corona virus 2019 (COVID-19) vaccination on perioperative outcomes after major vascular surgery. COVID-19 vaccination is associated with decreased mortality in patients undergoing various surgical procedures. However, the effect of vaccination on perioperative mortality after major vascular surgery is unknown. This is a multicenter retrospective study of patients who underwent major vascular surgery between December 2021 through August 2023. The primary outcome was all-cause mortality within 30 days of index operation or prior to hospital discharge. Multivariable models were used to examine the association between vaccination status and the primary outcome. Of the total 85,424 patients included, 19161 (22.4%) were unvaccinated. Unvaccinated patients were younger compared to vaccinated patients (mean age 68.44 +/- 10.37y vs 72.11 +/- 9.20y, P<0.001) and less likely to have comorbid conditions, including hypertension, congestive heart failure, chronic obstructive pulmonary disease, and dialysis. After risk factor adjustment, vaccination was associated with decreased mortality (OR 0.7, 95% CI 0.62 - 0.81, P<0.0001). Stratification by procedure type demonstrated that vaccinated patients had decreased odds of mortality after open AAA (OR 0.6, 95% CI 0.42-0.97, P=0.03), EVAR (OR 0.6, 95% CI 0.43-0.83, p 0.002), CAS (OR 0.7, 95% CI 0.51-0.88, P=0.004) and infra-inguinal lower extremity bypass (OR 0.7, 95% CI 0.48-0.96, P=0.03). COVID-19 vaccination is associated with reduced perioperative mortality in patients undergoing vascular surgery. This association is most pronounced for patients undergoing aortic aneurysm repair, carotid stenting and infrainguinal bypass.

The Role of Delirium on Short- and Long-Term Postoperative Outcomes Following Major Gastrointestinal Surgery for Cancer.

The growing burden of an aging population has raised concerns about demands on healthcare systems and resources, particularly in the context of surgical and cancer care. Delirium can affect treatment outcomes and patient recovery. We sought to determine the prevalence of postoperative delirium among patients undergoing digestive tract surgery for malignant indications and to analyze the role of delirium on surgical outcomes. Medicare claims data were queried to identify patients diagnosed with esophageal, gastric, hepatobiliary, pancreatic, and colorectal cancers between 2018 and 2021. Postoperative delirium, occurring within 30 days of operation, was identified via International Classification of Diseases, 10th edition codes. Clinical outcomes of interested included "ideal" textbook outcome (TO), characterized as the absence of complications, an extended hospital stay, readmission within 90 days, or mortality within 90 days. Discharge disposition, intensive care unit (ICU) utilization, and expenditures also were examined. Among 115,654 cancer patients (esophageal: n = 1854, 1.6%; gastric: n = 4690, 4.1%; hepatobiliary: n = 6873, 5.9%; pancreatic: n = 8912, 7.7%; colorectal: n = 93,325, 90.7%), 2831 (2.4%) were diagnosed with delirium within 30 days after surgery. On multivariable analysis, patients with delirium were less likely to achieve TO (OR 0.27 [95% CI 0.25-0.30]). In particular, patients who experienced delirium had higher odds of complications (OR 3.00 [2.76-3.25]), prolonged length of stay (OR 3.46 [3.18-3.76]), 90-day readmission (OR 1.96 [1.81-2.12]), and 90-day mortality (OR 2.78 [2.51-3.08]). Furthermore, patients with delirium had higher ICU utilization (OR 2.85 [2.62-3.11]). Upon discharge, patients with delirium had a decreased likelihood of being sent home (OR 0.40 [0.36-0.46]) and instead were more likely to be transferred to a skilled nursing facility (OR 2.17 [1.94-2.44]). Due to increased utilization of hospital resources, patients with delirium incurred in-hospital expenditures that were 55.4% higher (no delirium: $16,284 vs. delirium: $28,742) and 90-day expenditures that were 100.7% higher (no delirium: $2564 vs. delirium: $8226) (both p < 0.001). Notably, 3-year postoperative survival was adversely affected by delirium (no delirium: 55.5% vs. delirium: 37.3%), even after adjusting risk for confounding factors (HR 1.79 [1.70-1.90]; p < 0.001). Postoperative delirium occurred in one in 50 patients undergoing surgical resection of a digestive tract cancer. Delirium was linked to a reduced likelihood of achieving an optimal postoperative outcome, increased ICU utilization, higher expenditures, and a worse long-term prognosis. Initiatives to prevent delirium are vital to improve postoperative outcomes among cancer surgery patients.

Enhanced dye-sensitized solar cell performance and electrochemical capacitive behavior of bi-functional ZnO/NiO/Co3O4 ternary nanocomposite prepared by chemical co-precipitation method

Increasing prerequisites for sustainable energy storage and conversion technologies have necessitated the exploration of advanced materials with improved properties. Here, we present the synthesis and characterization of ZnO nanoparticles (NPs), ZnO/NiO, ZnO/Co3O4 and ZnO/NiO/Co3O4 NCs as promising bi-functional materials for dye-sensitized solar cell (DSSC) and electrochemical energy storage applications. A facile chemical co-precipitation approach was followed to synthesize pure ZnO NPs, ZnO/NiO, ZnO/Co3O4 and ZnO/NiO/Co3O4 NCs. The structural and morphological analyses revealed the successful integration of ZnO, NiO, and Co3O4 NPs and also the formation of well-defined core-shell and homogenous nanocomposite structures. The XRD and HRTEM analyses confirmed the crystalline nature and nanoscale morphology of synthesized materials, respectively. The photovoltaic performance of DSSC fabricated using ternary ZnO/NiO/Co3O4 NC photoanode showed optimum dye-loading and best solar to electrical energy conversion efficiency with Jsc of 11.29 mA cm−2 and ƞ of 4.66%, which was considerably higher than the DSSC fabricated using pure ZnO NPs photoanode (ƞ = 2.01%). The increment in photocurrent density (Jsc) could be ascribed to the perfect band alignment of NiO and Co3O4 NPs in the ternary NC. Further, the ZnO/NiO/Co3O4 NC photoanode integrated DSSC disclosed 97% retainment in energy conversion efficiency even after 10 days of operation. The electrochemical performance of supercapacitor fabricated using ternary ZnO/NiO/Co3O4 NC showed high specific capacitance of 534.7 Fg−1 at 1 Ag−1 with favourable rate ability (∼52% at 16 Ag−1), good cyclic stability (91.07%) and low internal resistance. Moreover, the ZnO/NiO/Co3O4 NC at a current density of 2 Ag−1 exhibited a significantly high capacitance value of 463.1 Fg−1, which was 1.93, 1.58 and 1.22 times greater than ZnO NPs, ZnO/Co3O4 NC and ZnO/NiO NC, respectively.

Process Intensification for Enhanced Fluoride Removal and Recovery as Calcium Fluoride Using a Fluidized Bed Reactor.

This study explored the feasibility of fluoride removal from simulated semiconductor industry wastewater and its recovery as calcium fluoride using fluidized bed crystallization. The continuous reactor showed the best performance (>90% fluoride removal and >95% crystallization efficiency) at a calcium-to-fluoride ratio of 0.6 within the first 40 days of continuous operation. The resulting particle size increased by more than double during this time, along with a 36% increase in the seed bed height, indicating the deposition of CaF2 onto the silica seed. The SEM-EDX analysis showed the size and shape of the crystals formed, along with the presence of a high amount of Ca-F ions. The purity of the CaF2 crystals was determined to be 91.1% though ICP-OES analysis. Following the continuous experiment, different process improvement strategies were explored. The addition of an excess amount of calcium resulted in the removal of an additional 6% of the fluoride; however, compared to this single-stage process, a two-stage approach was found to be a better strategy to achieve a low effluent concentration of fluoride. The fluoride removal reached 94% with this two-stage approach under the optimum conditions of 4 + 1 h HRT combinations and a [Ca2+]/[F-] ratio of 0.55 and 0.7 for the two reactors, respectively. CFD simulation showed the impact of the inlet diameter, bottom-angle shape, and width-to-height ratio of the reactor on the mixing inside the reactor and the possibility of further improvement in the reactor performance by optimizing the FBR configuration.

Sediment microbial fuel cell with biochar-modified cathode for remediation of black-odorous water sediments and analysis of microbial community

Sediment microbial fuel cells (SMFCs) generate electricity through microbial degradation of organic matter in sediments, and the cathode catalyst used for the oxygen reduction reaction is a key factor affecting the performance of SMFCs. To improve power production in SMFCs and remediate black-odorous water sediments, this study modifies the cathode carbon felt of the SMFC system with Enteromorpha prolifera (EP) biochar with high N and P content. The study demonstrated that the SMFC system with the modified cathode carbon felt (C-800℃/CF) exhibited superior power generation capabilities, achieving a maximum power density of 219.44 mW·m−2. Over 25 days of operation, the anode biofilm effectively degraded around 78.15% of total organic carbon, 79.55% of acid volatile sulfide, 74.78% of total nitrogen, 80.58% of ammonia nitrogen, and 77.46% of total phosphorus in the sediment. In addition, microbial community analysis showed that functional bacteria Thiobacillus, Acidaminobacter, Sulfurimonas, Bacteroidetes_vadinHA17, and Sideroxydans were the dominant genera in the anode biofilm.

Effects of carbon-based conductive materials on semi-continuous anaerobic co-digestion of organic fraction of municipal solid waste and waste activated sludge

Organic fraction of municipal solid waste (OFMSW) and waste activated sludge (WAS) are the most produced organic waste streams in urban centres. Their anaerobic co-digestion (AcoD) allows to generate methane (CH4) and digestate employable as renewable energy source and soil amendment, respectively, fully in accordance with circular bioeconomy principles. However, the widespread adoption of such technology is limited by relatively low CH4 yields that fail to bridge the gap between benefits and costs. Among strategies to boost AcoD of OFMSW and WAS, use of conductive materials (CMs) to promote interspecies electron transfer has gained increasing attention. This paper presents one of the few experimental attempts of investigating the effects of four different carbon(C)-based CMs (i.e., granular activated carbon – GAC, graphite – GR, graphene oxide – GO, and carbon nanotubes – CNTs) separately added in semi-continuous AcoD of OFMSW and thickened WAS. The presence of C-based CMs has been observed to improve CH4 yield of the control process. Specifically, after 63 days of operation (concentrations of GAC and GR of 10.0 g/L and of GO and CNTs of 0.2 g/L), 0.186 NL/gVS, 0.191 NL/gVS, 0.203 NL/gVS, and 0.195 NL/gVS of CH4 were produced in reactors supplemented with GAC, GR, GO, and CNTs, respectively, compared to 0.177 NL/gVS produced in the control process. Likewise, at the end of the test (i.e., after 105 days at concentrations of C-based CMs half of the initial ones), CH4 yields were 0.193 NL/gVS, 0.201 NL/gVS, 0.211 NL/gVS, and 0.206 NL/gVS in reactors supplemented with GAC, GR, GO, and CNTs, respectively, compared to 0.186 NL/gVS of the control process. Especially with regard to GR, GO, and CNTs, results obtained in the present study represent a significant advance of the knowledge on the effects of such C-based CMs to realistic and scalable AD process conditions respect to previous literature.

Reusable Underwater Superoleophobic Polyacrylamide Membranes for Effective Oil‐Water Separation and Dye Removal

AbstractWater contamination by oily wastes continues to rise with industrialization and pose a threat to marine ecosystem and public health. Water repellent special wettability membranes have been fabricated for oil removal. These superhydrophobic membranes have been fabricated utilizing hazardous chemicals such as fluorinated compounds, which again have shown toxicity. In contrast, environmentally friendly separation membranes are required for oily wastewater treatment. In this regard, we fabricated underwater superoleophobic membrane based on β‐cyclodextrin and acrylamide for efficient and effective water‐oil separation. Acrylamide polymeric membrane was prepared by free radical co‐polymerisation by incorporating acrylic acid and β‐cyclodextrin as monomer via crosslinking with N,N‐methylene bis‐acrylamide. FT‐IR and PXRD used for characterizing the prepared hydrogel and studied for morphological analysis by FE‐SEM. The oil and water wetting characterization of gels were evaluated, in ambient and submerged conditions. The dried gel showed gradual decrease of contact angle for both oil and water indicating liquid absorption with time. However, in completely water wetted state hydrogel was superoleophobic with a very high oil contact angle of ≥170°. The pre‐wetted hydrogel efficiently and effectively separated oil/water mixtures with ~99 % separation efficiency. Additionally, its effectiveness was monitored over several days of continuous separation operation. Interestingly, the hydrogel was also able to remove dye from water. The underwater superoleophobic acrylamide‐β‐cyclodextrin hydrogel demonstrated high oil recovery efficiency and indicated the potential for repeated oil‐water separation process.

Anthropogenic noise in terrestrial Antarctica: a short review of background information, challenges and opportunities

Anthropogenic noise is an inevitable by-product of human activities. However, the potential effects of human noise on terrestrial Antarctica’s ecosystems have been understudied. Documented impacts encompass stress, alterations in behavioural patterns, auditory masking, and, in severe instances, mortality. This Perspective note aims to call attention to human-generated noise as potential sources of impact on Antarctic wildlife and to highlight the potential of soundscape analysis as a flexible, cost-effective tool for environmental monitoring across Antarctica, complementing other non-invasive approaches. Acoustic monitoring in terrestrial environments has been extensively used in different parts of the world to assess biodiversity, monitor populations’ status and trends, and identify and monitor sources of anthropogenic disturbance. Technological advances in passive acoustic monitoring allow for the gathering of detailed information with little need of human attention, and powerful processing tools and algorithms enable researchers to analyse large collections of audio data. Cold climates limit battery-operated instruments, but solar panels in Antarctic summer trials revealed over 100 days of unattended operation, which is promising for the incorporation of acoustic monitoring in Antarctica’s environmental management toolbox.

Assessment of routine pre-operative group and save testing in patients undergoing cholecystectomy: a retrospective cohort study

Background Routine group and save (G&amp;S) testing is frequently performed prior to cholecystectomy, despite growing evidence that a targeted approach is safe and avoids unnecessary investigations. This retrospective cohort study explored frequency of testing in our unit, and rates of and independent pre-operative risk factors for peri-operative blood transfusion. Methods Health records of 453 consecutive adults who underwent cholecystectomy in a UK NHS trust were reviewed for blood transfusion up to 30 days post-operatively. We compared the need for transfusion against patient demographics, indication and urgency of surgery, and the number of prior emergency hospital attendances with gallstone complications. Logistic regression determined whether prior attendances with complications of gallstones independently predicted the need for transfusion. Results Peri-operative blood transfusions within 30 days of operation occurred in 1.1% of cases, with no requirement for uncrossmatched blood. Patients who received a blood transfusion tended to have higher American Society of Anesthesiologists (ASA) grades (p&lt;0.001), were more likely to have an underlying primary haematological malignancy (20.0% vs. 0.2%; p&lt;0.001) and prior emergency hospital attendances with gallstone complications (median 4 vs. 1; p&lt;0.001). Logistic regression showed each prior emergency attendance was associated with 4.6-fold odds of transfusion (p=0.019). Receiver operating characteristic curve analysis showed an area under the curve of 0.92. Three or more attendances predicted need for transfusion with 60.0% sensitivity and 98.0% specificity. Seventy-four percent had at least one G&amp;S sample taken pre-operatively, costing the trust approximately £3,800 per year in materials. Conclusions Pre-operative G&amp;S testing prior to cholecystectomy may not be routinely required. Increased frequency of prior emergency hospital attendances with gallstone complications and co-morbidities associated with coagulopathies were pre-operative risk factors for post-operative blood transfusion. More selective testing could provide large financial savings for health institutions without compromising patient safety.

Optimization and development of denser Chlorella vulgaris microalgae granules for easy harvesting via self-flocculation

Microalgae is widely utilized in water purification technology, biofuel production as well as in the synthesis of biopolymers. However, the separation of microalgae from its growth medium is the major issue that restricts the harvesting processes due to microalgae's lower density. In this study, the effect of environmental factors on microalgae granules development was investigated. Results from response surface methodology (RSM) revealed that maximum growth rate and biomass productivity were obtained at a photoperiod of 23.9 h, aeration rates of 2.4 L/min, inoculum concentration of 11 % and pH 6 respectively. The mixed liquor volatile suspended solids (MLVSS) value of the initial seed microalgae increased from 50 mg/L to 2978 mg/L after 70 days of cultivation. Microalgae productivity in this study is approximately 2 times faster than the standard suspension growing method. The microalgae settleability was significantly enhanced, as indicated by a major reduction in the sludge volume index (SVI30) from an initial value of >3000 to 58.51 mL/g, accompanied by an increase in settling velocity from virtually 0 to 19.2 cm/h and total harvesting time of 15 min. After 70 days of operation, smoothly settled, compact algal granules with largest sizes of 1.90 mm were obtained.

Rapid establishment of municipal sewage partial denitrification-anammox for nitrogen removal through inoculation with side-stream anammox biofilm without domestication

Mainstream partial denitrification anammox was achieved through inoculation of side-stream mature partial nitritation anammox biofilm without domestication. The contribution of anammox to nitrogen removal was 29.4 %. Moreover, prolonging anoxic hydraulic retention time and introducing side-stream nitrite under different carbon/nitrogen ratios enriched anammox bacteria. The abundance of anammox bacteria increased by ∼ 10 times ((2.19 ± 0.17) × 1012 copies gene / g dry sludge) with a total relative abundance of 18.51 %. During 258 days of operation, the contribution of anammox to nitrogen removal gradually increased to 68.8 %. The total nitrogen in the effluent decreased to 8.84 mg/L with a total nitrogen removal efficiency of 76.4 % under a carbon/nitrogen ratio of 3. This paper proposes a novel way to rapidly achieve mainstream partial denitrification anammox via inoculation with side-stream mature partial nitritation anammox biofilm. This method achieves advanced nitrogen removal from municipal wastewater, even under low carbon/nitrogen ratios.

Classification of laser beam profiles using machine learning at the ELI-NP high power laser system

The high power laser system at Extreme Light Infrastructure—Nuclear Physics has demonstrated 10 PW power shot capability. It can also deliver beams with powers of 1 PW and 100 TW in several different experimental areas that carry out dedicated sets of experiments. An array of diagnostics is deployed to characterize the laser beam spatial profiles and to monitor their evolution during the amplification stages. Some of the essential near-field and far-field profiles acquired with CCD cameras are monitored constantly on a large screen television for visual observation and for decision making concerning the control and tuning of the laser beams. Here, we present results on the beam profile classification obtained from datasets with over 14 600 near-field and far-field images acquired during two days of laser operation at 1 PW and 100 TW. We utilize supervised and unsupervised machine learning models based on trained neural networks and an autoencoder. These results constitute an early demonstration of machine learning being used as a tool in the laser system data classification.

Effects of Preoperative Glucocorticoid Use on Patients Undergoing Single-Level Lumbar Fusions: A Retrospective Propensity Score-Matched Registry Study.

Objective Spinal fusions are gaining popularity as a means of treating spinal deformity and instability from a range of pathologies. The prevalence of glucocorticoid use has also increased in recent decades, and their systemic effects are well-documented. Although commonly used in the preoperative period, the effects of steroids on outcomes amongpatients undergoing spinal fusions are inadequately described. This study compares the oddsof developing complications amongpatients who underwent single-level lumbar fusions with and without preoperative glucocorticoid use in hopes of establishing more evidence-based parameters for guiding preoperative steroid use. Methods The TriNetX multi-institutional electronic health record database was used to perform a retrospective, propensity score-matched analysis of clinical outcomes of two cohorts of patients who underwent posterior or posterolateral single-level lumbar fusions with and without interbody fusion, those who used glucocorticoids for at least one week within a year of fusion and those who did not. The outcomes of interest were examined within 30 days of the operation and included death, reoperation, deep or superficial surgical site infection (SSI), pneumonia, reintubation, ventilator dependence, tracheostomy, acute kidney injury (AKI), renal insufficiency, pulmonary embolism (PE) or deep venous thrombosis (DVT), urinary tract infection (UTI), emergency department (ED) visit, sepsis, and myocardial infarction (MI). Results The odds of developing pneumonia within 30 days of spinal fusion in the cohort that used glucocorticoids within one year of operation compared to the cohort without glucocorticoid use was 0.67 (p≤0.001, 95% CI: 0.59-0.69). The odds of requiring a tracheostomy within 30 days of spinal fusion in the cohort that used glucocorticoids within one year of operation compared to the cohort without glucocorticoid use was 0.39 (p≤0.001, 95% CI: 0.26-0.60).The odds of reoperation, deep and superficial SSI, and ED visits within 30 days of operation were significantly higher for the same glucocorticoid-receiving cohort, with odds ratios of 1.4 (p=0.003, 95% CI: 1.11-1.65), 1.86 (p≤0.001, 95% CI: 1.31-2.63), 2.28 (p≤0.001, 95% CI: 1.57-3.31), and 1.25 (p≤0.001, 95% CI: 1.17-1.33), respectively. After propensity score-matching, there was no significant difference between the odds of death, DVT, PE, MI, UTI, AKI, sepsis, reintubation, and ventilator dependence between the two cohorts. Conclusion In support of much of the current literature regarding preoperative glucocorticoid use and rates of complications, patients who underwent a single-level lumbar fusion and have used glucocorticoids for at least a week within a year of operation experienced significantly higher odds of reoperation, deep and superficial SSI, and ED visits. However, these patients using glucocorticoids were also found to have lower odds of developing pneumonia, renal insufficiency, and tracheostomy requirement than those who did not use steroids within a year of surgery.

Insight into the role of chitosan in rapid recovery and re-stabilization of disintegrated aerobic granular sludge

The disintegration and instability of aerobic granular sludge (AGS) systems during long-term operation pose significant challenges to its practical implementation, and rapid recovery strategies for disintegrated AGS are gaining more attention. In this study, the recovery and re-stabilization of disintegrated AGS was investigated by adding chitosan to a sequencing batch reactor and simultaneously adjusting the pH to slightly acidic condition. Within 7 days, chitosan addition under slight acidity led to the re-aggregation of disintegrated granules, increasing the average particle size from 166.4 μm to 485.9 μm. Notably, sludge volume indexes at 5 min (SVI5) and 30 min (SVI30) decreased remarkably from 404.6 mL/g and 215.1 mL/g (SVI30/SVI5 = 0.53) to 49.1 mL/g and 47.6 mL/g (SVI30/SVI5 = 0.97), respectively. Subsequent operation for 43 days successfully re-stabilized previous collapsed AGS system, resulting in an average particle size of 750.2 μm. These mature and re-stabilized granules exhibited characteristics of large particle size, excellent settleability, compact structure, and high biomass retention. Furthermore, chitosan facilitated the recovery of COD and nitrogen removal performances within 17–23 days of operation. It effectively facilitated the rapid aggregation of disintegrated granules by charge neutralization and bridging effects under a slightly acidic environment. Moreover, the precipitated chitosan acted as carriers, promoting the adhesion of microorganisms once pH control was discontinued. The results of batch tests and microbial community analysis confirmed that chitosan addition increased sludge retention time, enriching slow-growing microorganisms and enhancing the stability and pollutant removal efficiency of the AGS system.

Engineering hybrid conductive electrochemically active biofilms enable efficient interfacial electron transfer and syntrophic carbon metabolism

Supply of carbon-based nanomaterials (e.g., carbon nanotubes, CNTs) to develop highly conductive electrochemically active biofilms (EABs) is a potential strategy for facilitating extracellular electron transfer (EET) in bioelectrochemical systems (BESs). Understanding of the underlying CNTs-mediated EET behaviors is helpful to further advance the practical application of BESs. Here, the cognitive influence of CNTs on bioelectrocatalytic activity and electron transfer efficiency of EABs were elucidated. CNTs can be embedded into EABs to form hybrid conductive biofilms (CNTs/EABs), achieving a high current density (7.4 ± 1.40 A m−2) and excellent coulombic recovery (46.0 ± 2.70 %) over 100 days of steady operation. The supply of CNTs can mitigate the dependence of exoelectrogens (such as Geobacter) on outer membrane cytochromes (OMCs) and conductive pili due to their down-regulated genes expression in CNTs/EABs, but it can significantly improve microbial carbon metabolism because physically high-conductive CNTs can establish rapid EET pathways, which may reduce the necessity for cells to invest metabolic energy in producing conductive pili and cytochromes that are required in the absence of CNTs. Such enhancement in electron transfer rate may be caused by the interfacial interaction between OMCs and CNTs, resulting in an order of magnitude higher than in the control (5.5 ± 1.60 s−1vs. 0.28 ± 0.04 s−1) and without compromising of mass diffusion. This study provides comprehensive insight into the role of carbon-based nanomaterials in provoking interfacial electron transfer and renewable energy recovery.

External resistance as a potential tool for bioelectricity and methane emission control from rice plants in hydroponic microbial fuel cell

Recently, hydroponic plant microbial fuel cell (H-PMFC) was incorporated into cultivation medium to decrease methane (CH4) production while generating bioelectricity. However, no information is available about the effect of the external/internal resistance (Rext/Rint) ratio on the performance of H-PMFCs. To study the possibility of controlling biomass production, bioelectricity generation, and CH4 emissions from hydroponic rice plants (Oryza sativa L.) under different Rext/Rint ratios. In this study three H-PMFCs were operated as follows: H-PMFC-A had external resistance (Rext) lower than internal resistance (Rint); H-PMFC-B had Rext equal to Rint, and H-PMFC-C had Rext higher than Rint. Results showed that H-PMFC-B (Rext = Rint) has the highest biomass yield. H-PMFC-C (Rext > Rint) displayed the highest average power density (PDmax), which was 4.77 and 1.23 times higher than H-PMFC-A and H-PMFC-B over 131 days of operation. The PDmax was obtained from H-PMFC-C of 536.79 mW/m3 when Rext/Rint = 150 %. The highest current with the lowest CH4 was produced by H-PMFC-A (0.14 mA and 453.52 ± 0.28 g/m2/h). The CH4 emission exhibits an inverse trend with current production, which decreasing with the Rext/Rint decreased from 50 % to 5 %. The total CH4 emission flux in H-PMFC-A was 1.42 and 2.07 times lower than H-PMFC-B and H-PMFC-C, respectively. Furthermore, the COD removal rate in H-PMFCs negatively correlates with Rext/Rint, and the Rext does not affect the COD removal rate when 50 % ≤ Rext/Rint ≤ 150 %. The above results indicated that the performance of H-PMFCs can be controlled by changing the Rext/Rint ratio of H-PMFC according to actual needs. If the goal is to achieve higher biomass production, then Rext = Rint; to obtain the highest PDmax, then Rext > Rint; to obtain the highest current and lowest CH4 generation, then Rext < Rint.

Mechanical stirring of bulk-stored maize in steel bins to suppress maize weevils and other beetle populations

This study investigates the effectiveness of periodic stirring as a non-chemical approach to suppress maize weevils, Sitophilus zeamais, and other beetle populations in large-scale grain storage bins. The research was conducted in a farm steel bin with a diameter of 9.8 m holding 127 Mg of maize, and a control bin of diameter 7.3 m holding 102 Mg of maize. Both bins were loaded with maize at 13% moisture and infested at a commercial tolerance rate of 2 weevils/kg of maize. Probe traps monitored beetle populations except for S. zeamais before stirring was initiated. Maize samples were collected at depths of 0, 0.9, 1.8 and 2.7 m with a vacuum-probe sampler prior to stirring and at 10, 20, 30 and 40 days of continuous stirring machine operation. Stirring achieved 100% control of live S. zeamais while the control bin experienced an increase in its S. zeamais population after 40 days. The stirring process also led to a significant reduction in dominant beetle populations such as hairy fungus beetles, Typhaea stercorea, and foreign grain beetles, Ahasuerus advena. Although the quality of maize in both bins changed at different depths and storage times, the treatment bin had higher bulk density (732.7 ± 3.98 kg/m3 to 768.9 ± 2.41 kg/m3), lower insect damage (0.02 ± 0.02% to 0.9 ± 0.28%), and higher allowable storage time (>249 days). Moisture content and molded kernels increased in the control bin, reaching 26.4 ± 1.29% and 3.2 ± 0.53%, respectively. The average percentage of broken corn and foreign material (BCFM) in the sweepings on the floor of the emptied treatment bin was 6.5 times higher than that in the control bin. Calculated packing factor values below 1.5 from the sweepings indicated that BCFM concentrations did not affect airflow. Stirring maize provides an alternative to the use of chemicals to control stored maize insect pests at a production scale.

Anaerobic Co-Digestion of Agro-Industrial Waste Mixtures for Biogas Production: An Energetically Sustainable Solution

In a climate crisis, searching for renewable energy sources is urgent and mandatory to achieve a low-carbon society. The food industry is an attractive source for providing different organic waste with great potential for energy generation, avoiding the environmental impacts of its inadequate management at the disposal stage. This manuscript determines the feasibility of using three agro-industrial byproducts for biogas production with a mesophilic anaerobic digestion process. Three mixture samples such as tomato pulp with olive cake (TP-OC), apple pomace with olive cake (AP-OC), and tomato pulp with apple pomace (TP-AP) at a 1:1 w/w ratio were evaluated using bovine manure as inoculum. During 7 to 12 days of operation, results indicate that TP-OC achieved the highest biogas production yield with 1096 mL/L (with up to 70% methane), followed by AP-OC and TP-AP with 885 (62% methane) and 574 mL/L (69% methane), respectively. Experimentally, TP-OC consistently encompassed the highest biogas and methane production and fit the kinetic models, whereas the modified Gompertz model produced the best fit (R2 = 99.7%). This manuscript supports the preference for mixing byproducts from the agro-industrial sector rather than using them individually for biogas production.

JUNO high purity nitrogen plant

The Jiangmen Underground Neutrino Observatory (JUNO) is a 20 kt low level radioactivity liquid scintillator detector in a laboratory 650 m underground. An excellent energy resolution and a large volume offer exciting opportunities for addressing many important topics in neutrino physics. High purity nitrogen is an important factor to ensure the low background of the JUNO detector. High Purity Nitrogen (HPN) is used for detector purging, pipe cleaning, and scintillator purification, among other things in JUNO. According to JUNO’s requirements, the radon concentration in HPN should be less than 10 μBq/m3. To meet this requirement, A high-purity nitrogen plant with 100 Nm3/h maximum rate was designed and constructed. Low-temperature adsorption technology is used to remove radioactive impurities in nitrogen. High purification efficiency was ensured by using an activated carbon column with high column height-to-diameter ratio. Electrostatic collection and low-temperature enrichment methods are combined to measure radon in nitrogen. After ten days of continuous operation at 50 Nm3/h flux rate, the plant can to reduce the radon concentration in nitrogen from 37.4±1.8μBq/m3 to less than 1.33 μBq/m3. After HPN with flow rate of 50 Nm3/h passing through low-background pipeline (About 1.3 km), the radon concentration of HPN is 5.6±0.6μBq/m3.