Water hammer is the unsteady flow in conduits due to sudden change of velocities in pipelines and poses it to danger. Sensitivity analysis is performed to show the effect of pump and pipeline ...parameters on the maximum and minimum head just downstream the pump after pump power failure. A new approach to find the required gas volume in a hydropneumatic tank (air vessel) to protect the pipeline using artificial neural networks (ANNs) is introduced. About 760 runs were generated using Bentley Hammer v8i. For each run, the maximum and minimum head just downstream the pump were calculated for a pump power failure. Two MATLAB codes are written to use networks for finding the best design that guarantees the pressure in the pipeline is within the allowable range. The results showed that pump inertia and wave celerity have a very small effect on the maximum and minimum heads.
1,4-Dioxane is widely used in industry and seriously contaminates the ecosystem due to intentional discharge into water streams. Treatment of water/wastewater containing 1,4-dioxane is greatly ...growing since, it is listed as a priority pollutant and a hazardous compound for humans and environment. Degradation pathways of 1,4-dioxane in biological and advanced oxidation processes (AOPs) are extensively discussed in this review to identify potential bottlenecks which limit 1,4-dioxane removal processes and possibly allow the identification of the needed treatment approach. Furthermore, the efficiency of hybrid photocatalytic oxidation processes for treatment of wastewater rich 1,4-dioxane is comprehensively performed. During the degradation of 1,4-dioxane, several by-products/intermedi- ates are produced as the consequence of the ring opening of 1,4-dioxane molecules, namely: ethylene glycol, glycolic acid, oxalate anion and formic acid. The efficiency of AOPs for oxidation of 1,4-diox- ane is an excellent technology; however, the treatment cost is still quite high. Phytoremediation of water/wastewater containing 1,4-dioxane is a promising approach where conversion of 1,4-dioxane into biomass is performed avoiding severe pollution conditions.
Background: Giant papillary conjunctivitis GPC is a type of inflammatory disease of the eye formed of "giant" papillae in the superior tarsal conjunctiva.Aim of the work: We have compared the effect ...of refractory giant papillary conjunctivitis management surgically with excision with and without conjunctival autograft or amniotic membrane transplantation.Patients and Methods: This was a randomized controlled trial conducted in the Ophthalmology Department, Al-Azhar University Hospitals, Egypt in the period from January 2022 to January 2023 included 45 patients presenting with giant papillary conjunctivitis who were treated surgically by one of the following techniques divided into 3 groups: group 1; included 15 patients had undergone simple surgical excision of giant conjunctival papillae only, group 2; included 15 patients had undergone surgical excision with conjunctival autograft and group 3; included 15 patients had undergone surgical excision with amniotic membrane transplantation AMT.Results: Results of this study reported that recurrence occurred higher in simple excision 10.7% with a significant difference between groups p value=0.021, also dry eye was higher in the same group 17.9% with no significant difference. Conjunctival inflammation was higher in excision with AMT 10% with no significant difference. Scar had been formed in one eye of simple excision patients only while vascularization was in one eye of excision with autologous conjunctival graft only.Conclusion: AMT or autologous conjunctival graft following excision of giant conjunctival papillae may reduce the chances of recurrence; also, surgical outcomes are better than that reported with the simple excision.
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•8 mg/L of sodium chlorite enhanced H2 yield to 119.6 ± 7.8 mL/gTVS.•Sodium chlorite exhibited higher lignin destruction.•Phenolic compounds inhibit enzyme activities and bacterial ...counts.•Maximum profit was 0.80 $/gWH/day using 8.0 mg NaClO2/L.
This study investigated the direct supplementation of sodium chlorite (NaClO2) in acidic fermentation process rather than using NaClO2 as a pretreatment agent. This approach targets saving both of the cost of external acetic acid that needs to be added in pretreatment and the loss of polysaccharide, which simultaneously occurs during pretreatment process. Whereas, fermentation of water hyacinth (WH) provided quite low H2 yield (HY) of 39.7 ± 2.5 mL/gTVS and lignin destruction of 2.6 ± 0.2%. Cellulase and xylanase enzymes amounted to 2.15 ± 0.18 and 1.81 ± 0.14 U/mL, respectively. Enterobacter and Clostridium sp. accounted for 2.41 ± 0.15 × 105 and 4.02 ± 0.27 × 104 cfu/mL, respectively. However, NaClO2 addition significantly augmented HY, cellulase and xylanase enzymes to 119.6 ± 7.8 mL/gTVS, 3.46 ± 0.21 and 2.09 ± 0.23 U/mL at dosage of 8.0 mg/L, respectively. Moreover, cellulose, hemicellulose and lignin degradation efficiencies were maximized to 57.8 ± 3.1, 46.3 ± 3.8 and 31.6 ± 1.6%, respectively. Enterobacter and Clostridium sp. counts were 4.23 ± 0.28 × 105 and 9.75 ± 0.52 × 104 cfu/mL, respectively in the batches supplemented with NaClO2. Nevertheless, at a dosage exceeding 8.0 mg/L, the HY (26.1 ± 2.0 mL/gTVS) and bacterial count was highly deteriorated due to the excessive production of inhibitory phenolic compounds of 1.61 ± 0.12 g/L in the medium where the destruction of lignin was quite high (38.8 ± 2.4%).
A series of idealized prescribed soil moisture experiments is performed with the atmosphere/land stand-alone configuration of the Community Earth System Model, version 1, in an effort to find sources ...of predictability for high-impact stationary wave anomalies observed in recent boreal summers. We arbitrarily prescribe soil water to have a zero value at selected domains in the continental United States and run 100-member ensembles to examine the monthly and seasonal mean response. Contrary to the lack of a substantial response in the boreal winter, the summertime circulation response is robust, consistent, and circumglobal. While the stationary wave response over the North America and North Atlantic sectors can be well explained by the reaction of a linear dynamical system to heating anomalies caused by the imposed dry land surface, nonlinear processes involving synoptic eddies play a crucial role in forming the remote response in Eurasia and the North Pacific Ocean. A number of other possible factors contributing to the circulation responses are also discussed. Overall, the experiments suggest that, in the boreal summer, soil moisture may contribute to the predictability of high-impact stationary wave events, which can impact regions that are great distances from these source regions.
•LCFAs-inhibition found to be saturation index, temperature, and concentration dependent.•Syntrophus, Syntrophothermus, Syntrophomonas and Thermosyntropha can degrade LCFAs.•Cations supplementation ...catalyzed LCFA salt formation.•Natural adsorbents can enhance AD process via LCFAs capture.
The inhibition of the anaerobic digestion (AD) process, caused by long chain fatty acids (LCFAs), has been considered as an important issue in the wastewater treatment sector. Proper understanding of mechanisms behind the inhibition is a must for further improvements of the AD process in the presence of LCFAs. Through analyzing recent literature, this review extensively describes the mechanism of LCFAs degradation, during AD. Further, a particular focus was directed to the key parameters which could affect such process. Besides, this review highlights the recent research efforts in mitigating LCFAs-caused inhibition, through the addition of commonly used additives such as cations and natural adsorbents. Specifically, additives such as bentonite, cation-based adsorbents, as well as zeolite and other natural adsorbents for alleviating the LCFAs-induced inhibition are discussed in detail. Further, panoramic evaluations for characteristics, various mechanisms of reaction, merits, limits, recommended doses, and preferred conditions for each of the different additives are provided. Moreover, the potential for increasing the methane production via pretreatment using those additives are discussed. Finally, we provide future horizons for the alternative materials that can be utilized, more efficiently, for both mitigating LCFAs-based inhibition and boosting methane potential in the subsequent digestion of LCFA-related wastes.
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LAND—ATMOSPHERE INTERACTIONS Santanello, Joseph A.; Dirmeyer, Paul A.; Ferguson, Craig R. ...
Bulletin of the American Meteorological Society,
06/2018, Letnik:
99, Številka:
6
Journal Article
Recenzirano
Odprti dostop
Land–atmosphere (L-A) interactions are a main driver of Earth’s surface water and energy budgets; as such, they modulate near-surface climate, including clouds and precipitation, and can influence ...the persistence of extremes such as drought. Despite their importance, the representation of L-A interactions in weather and climate models remains poorly constrained, as they involve a complex set of processes that are difficult to observe in nature. In addition, a complete understanding of L-A processes requires interdisciplinary expertise and approaches that transcend traditional research paradigms and communities. To address these issues, the international Global Energy and Water Exchanges project (GEWEX) Global Land–Atmosphere System Study (GLASS) panel has supported “L-A coupling” as one of its core themes for well over a decade. Under this initiative, several successful land surface and global climate modeling projects have identified hot spots of L-A coupling and helped quantify the role of land surface states in weather and climate predictability. GLASS formed the Local Land–Atmosphere Coupling (LoCo) project and working group to examine L-A interactions at the process level, focusing on understanding and quantifying these processes in nature and evaluating them in models. LoCo has produced an array of L-A coupling metrics for different applications and scales and has motivated a growing number of young scientists from around the world. This article provides an overview of the LoCo effort, including metric and model applications, along with scientific and programmatic developments and challenges.
•Anammox baffled reactor (AnBR) revealed moderate start-up period of 53 days.•Anammox sludge characteristics have statistically robust relationships.•ANN effectively simulated AnBR with R2 and MSE of ...0.99 and 0.002, respectively.•AnBR at NLR of 4.04 kg-N/m3/day exhibited net present value of $48100.9.
Anammox baffled reactor (AnBR) had a moderate start-up period of 53 days. Interestingly, tangled relationships between key parameters affecting anammox performance were observed, i.e., polynomial function for nitrogen loading rate (NLR) with extracellular polymeric substances (EPS), linear relationships between EPS with granules diameter, granules diameter with settling velocity, and settling velocity with biomass concentration. The correlation coefficients (R2) were 0.97, 0.84, 0.86, and 0.88, respectively. Furthermore, a multi-layered feed forward artificial neural network (ANN) was utilized for simulating and predicting the performance of AnBR. An ANN structure of two hidden layers with four neurons at 1st layer and eight neurons at 2nd layer achieved the best goodness of fit with the minimum mean squared error (MSE) and maximum R2 of 0.002 and 0.99, respectively. Additionally, economic assessment stated that using AnBR at NLR of 4.04 ± 0.10 kg-N/m3/day achieved the maximum net present value of $48100.9.
Arteriovenous grafts (AVGs) are frequently needed in hemodialysis (HD) patients with unsuitable superficial veins. First cannulation of standard arteriovenous grafts (sAVGs) still require about ...2 weeks after implantation. Early cannulation arteriovenous grafts (eAVGs) were suggested to overcome this shortcoming. The present randomized study proposed to compare the clinical outcomes of sAVGs and eAVGs in HD patients.
The present single-center randomized clinical study recruited 477 HD patients indicated for AVG creation. They included 236 in the sAVG group and 241 in the eAVG group. Eligible patients were simply randomized and allocated to the studied groups using 1:1 allocation ratio. Blinding was secured using the sealed envelope technique. Enrolled patients were followed up for 12 months. The primary outcome in the present study was primary, primary assisted, and secondary patency rates at 12 months. Other outcome parameters included time to first cannulation, graft complications, and mortality.
Comparison between the studied groups regarding the primary outcomes revealed no statistically significant differences. Primary patency rate was 65.7% and 68.0% (P = .58) at 6 months and 53.8% and 56.4% (P = .57) at 12 months in the sAVG and eAVG groups, respectively. Primary assisted patency rate was 70.8% and 69.7% (P = .8) in patients with sAVG and eAVG, whereas the reported rates at 12 months were 59.3% and 61.0% (P = .71), respectively. Secondary patency rate was 78.4% and 73.9% (P = .25) at 6 months and 67.8% and 69.7% (P = .65) at 12 months in the sAVG and eAVG groups, respectively. As expected, patients in the eAVG group experienced significantly earlier cannulation when compared with patients in the sAVG group (median, 3.0 days; range, 1.0-9.0 days vs 19.0 days; range, 15.0-22.0 days; P < .001).
Patients in the eAVG group have comparable outcomes to those in the sAVG group at 12 months with the added advantage of earlier time to first cannulation.
Solar photo-Fenton process for degradation of four types of pharmaceuticals namely amoxicillin, ampicillin, diclofenac, and paracetamol was studied. Experiments were carried out by solar compound ...parabolic collectors (CPCs) reactor with borosilicate tubes and capacity of 4.0L. Oxidation of each pharmaceutical was investigated individually using 100mg/L synthetic solution. The influence of irradiation time, initial pH value, and dosage of Fenton reagent were investigated. Paracetamol, and amoxicillin were completely removed after 60 and 90min of irradiation respectively. Complete degradation of ampicillin and diclofenac was occurred after 120min. The removal of pharmaceuticals was significantly affected by changing pH values from 3 to 10. Complete removal of all pharmaceuticals was achieved under acidic conditions (pH 3). The optimum H2O2 and FeSO4.7H2O dosage were 1.5 and 0.5g/L, respectively. The results of photo-Fenton experiments fitted the pseudo-first order kinetic equation with high correlation. Costs estimation of 30m3/d full scale solar photo-oxidation plant was assessed.
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