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Produced water is the largest source of wastewater in the oil and gas industry. One of the approaches to manage excess produced water is to increase its reuse opportunities using desalination technologies such as reverse osmosis. This article presents an experimental study using high temperature reverse osmosis membranes to treat produced water in a relatively high temperature range. Synthetic water was prepared using the produced water formula containing 10,600 mg/L of Total Dissolved Solids (TDS) and 83 mg/L of boron. Different pH and temperature conditions were evaluated to simulate the field operation conditions. The selected membrane module demonstrated high boron rejection at the test condition of pH 11 in the temperature range of 25 °C–60 °C. More than 98% of boron rejection was achieved at the maximum testing temperature of 60 °C. The membrane software was calibrated with the lab test data. Further lab studies using field produced water at 55 °C showed consistent results for boron and TDS rejections. Calibrated membrane software was used to perform system-level design at various recovery rates; the projected water quality and pressures had good alignment with the lab test results. The consistent membrane performance in this study provides an opportunity to undertake future field study using the RO membranes to treat high temperature produced water.

The need for wastewater treatment does not only arise from an environmental conservation point of view. But also, from the fact that it can be reused for secondary proposes. The most of hospitals being present in urban space, still their wastewater treatment are not fully explored. The Fluidized Aerobic Bed Bioreactor (FABB) treats wastewater in a liquid-solid phase among various wastewater treatment processes. This study employed a fluidized aerobic bed reactor coupled with a tube settler for hospital wastewater treatment. The treatment efficiency was evaluated based on the removal of pollutants and nutrients with associated parameters pH, Alkalinity, total suspended solids (TSS), and mixed liquor suspended solids (MLSS). The efficiency was determined by evaluating the influent and effluent quality of samples. The BOD5 was reduced at an average of 69% in FABB, and for tubesettler, it resulted in consumption of only 39%. Similar types of results were obtained when considering it for COD, i.e., 72% and 38%, respectively, for FABB and tube settler. The nitrification was observed in both nitrate accumulation by 103% and 3.65% in FABB and tube settler. In the absence of anaerobic conditions, the denitrification process could not be achieved. Hence the cycle was not completed. Lower phosphate reduction was achieved, 63% and 23%, however concentration in influent were below the permissible limit of 5 mgL−1. The study concludes that FABB can be successfully employed for hospital wastewater treatment. Additionally, tubesettler may be used in place of a secondary clarifier in the treatment of hospital wastewater.

More sustainable processes capable to minimize the demand for chemical inputs and the generation of toxic wastes are essential to scale up the pretreatment strategies applied to lignocellulosic biomass for bioenergy production. This study aimed to evaluate the reuse of the black liquor (hydrolysate) generated after alkaline pretreatment as a sustainable and cheaper strategy to increase biodegradability of grass clippings (GC) and enhance process economic feasibility. Batch anaerobic digestion experiments were carried out at mesophilic temperature (37 °C) using KOH and NaOH solutions at a concentration of 5% (w/v). The methane yield of the untreated substrate was 227 LN CH4 kg−1 VS. Methane yields obtained from pretreated grass clippings using KOH and NaOH at 5% were increased to 30.5% and 34.5% and the hydrolysate generated after the pretreatments showed statistical (p

Effects of MW treatment, combined MW-alkali (MA) treatment, and combined MA-water elutriation (MAW) treatment on sludge solubilization were studied; this work aims at the recovery of carbon sources and nutrients. Effects of MW power input, MW heating time, NaOH dosages, alkali treatment durations, and sludge solids concentration on sludge solubilization were explored. These treatments produced good chemical oxygen demand (COD) dissolution degree outcomes, with optimal values of 12.38 ± 0.20% (MW treatment), 54.68 ± 0.28% (MA treatment), and 55.58 ± 0.68% (MAW treatment), respectively. Besides, MW treatment could disrupt sludge flocs and biomass cell membranes, with a 120 mg/L volatile fatty acids (VFAs) release (280 W for 5 min). A reduction of VSS/TSS ratio was 10.50% by alkali treatment, and 22.60% by MA treatment. Compared with MA treatment only, water elutriation after MA resulted in outstanding nutrients release, with optimal dissolution degrees increasing from 67.87 ± 0.52% to 81.87 ± 0.60% (TP), and 56.08 ± 0.94% to 73.73 ± 1.04% (TN), respectively. MW power inputs, MW heating duration, alkali treatment time, and especially NaOH dosages had significant effects on sludge solubilization, but solids concentration had a minor effect on sludge solubilization. Moreover, higher MW power input, longer MW heating time, and greater sludge solids concentration could cause gelatinization and even carbonization.

Solar photo-Fenton process with ferric nitrilotriacetate has great potential for contaminant of emerging concern (CEC) removal from municipal effluents. To scale-up the process, gaining know-how about the effect of temperature and photon absorption is fundamental. This work presents for the first time an in-depth study about the effect of both variables on the reaction mechanism. To this end, imidacloprid (IMD) was selected as a surrogate CEC (100 μg/L). The experimental plan comprised two steps: (i) lab-scale experiments in simulated effluents, and (ii) experiments at pilot-scale in raceway pond reactors with actual effluents. Despite the process being photo-limited in the volumetric rate of photon absorption range of 103–413 μE/m3·s, the increase in the liquid depth from 5 to 15 cm allowed improving the treatment capacity, achieving more than 80 % of IMD removal with reaction times around 30 min. These results provide the necessary knowledge for photoreactor design and continuous flow operation.

Wastewater reuse has been progressively popular as a practical method for protecting aquatic environment and water sources. In this work, the chlor(am)ine-UV oxidation was employed to enhance membrane system performance during potable water reuse. The achievements were comprehensively evaluated from the aspects of membrane fouling mitigation and organic matter removal. The various dosages of chlorine and UV irradiation were applied and the effects of typical inorganic species in wastewater effluent were considered as well. It was suggested that the chlor(am)ine-UV oxidation could significantly promote the normalized flux by 94.9% under the condition of 10 mg L-1/960 mW cm-2 (chlorine dose and UV irradiation density). And the certain lower concentration of inorganic pollutant in wastewater effluent could further prevent the membrane fouling accumulation, especially for the reversible and total fouling resistances. The model fitting of filtration flux revealed that the combination of pore blockage and cake filtration was responsible for the mechanisms of fouling formation, and the transition moment was adjusted by the oxidation process. The characteristics of dissolved organic matter were modified as well, which were positive for the improvement of membrane effluent quality and security. The results demonstrated that the combination of the chlor(am)ine-UV oxidation and ultrafiltration could be a promising alternative for efficient wastewater recycle and reuse.

The complexity of textile effluents demands innovative treatment capable to promote the water reuse and by-products recovery. Taking this into account, an advanced oxidation process (AOP, photo-Fenton) was combined with microfiltration (MF) and nanofiltration (NF) in two distinctive processes: (1) MF-NF-AOP(c) and (2) MF-AOP-NF; aiming for the NF concentrate treatment in the first, and as a NF pre-treatment in the second. The MF was able to reject > 99.1% of the indigo blue, which can be reused in the dyeing process. The AOP applied to MF permeate had a higher COD degradation (78%, compared to 69% when applied to NF concentrate treatment), but the residual iron content resulted in a pronounced concentration polarization effect in the NF. Due to that fact, the NF in the second treatment systems had a higher fouling rate and lower permeate flux (average value: 19 L/m2h) compared to the first (average value: 38 L/m2h). In both cases, the residual iron concentration in the NF concentrate and in the AOP effluent prevented their reuse. However, the NF permeate from both treatment processes can be considered for yarn washing-off and equipment washing down. Furthermore, for the combination MF-NF-AOP(c), the NF permeate met the requirements to be recycled back to the process. The better performance of the first system (MF-NF-AOP(c)) in textile wastewater treatment was reassured by its lower operating expenditure (0.421 US$/m3) compared to MF-AOP-NF (0.736 US$/m3). Overall, the treatment combining MF-NF-AOP(c) was considered the most cost-effective alternative for textile wastewater treatment reuse.

Stevia sugar is widely used in food owing to its advantages of low calorie content and high sweetness. In the production of stevia sugar, stevia leaves are immersed in water to obtain a crude liquor, which contains many impurities, such as proteins, polysaccharides, organic acids, etc. These impurities are removed typically by coagulation and filtration. At present, suppliers of stevia mainly use a “lime + ferrous sulfate (FeSO4)” process as the pretreatment, but residual SO42− can cause hydrogen sulfide corrosion and Ca2+ can affect the safety of subsequent boilers in the process. In this study, polyaluminium ferric chloride (PAFC) was evaluated as a superior coagulant to FeSO4, together with ultrafiltration (UF) and nanofiltration to remove flocs and other organic contaminants. It was found that coagulation by PAFC out-performed FeSO4 and was unaffected by pH, while the performance of FeSO4 was sensitive to pH. At pH 10, FeSO4 had an enhanced coagulation efficiency, but formed soluble Fe2+ complexes with organic substances in the original solution, which adversely affected the quality of the filtrate. Compared with a UF membrane, the NF membrane was more effective in removing contaminants, and more tolerant to membrane fouling. In addition to hydrodynamic flux, measurement of trans-membrane electrical current were used to reflect the severity of membrane fouling. The combination of PAFC as coagulant without pH adjustment, and ultrafiltration, was found to be a simpler and superior treatment for stevia liquor with a high degree of contaminant separation, and avoidance of problems caused by SO42− and Ca2+.

The commercial feasibility regarding conversion of the high-solid-loading microalgal suspensions for high-titer biofuels production is questionable owing to incomplete utilization and high processing costs. In this study, the production of multiple highly concentrated biofuels (bioethanol, higher alcohols, and biodiesel) was achieved through cost-effective integrated approach (pretreatment, serial fermentation of carbohydrate/protein, and transesterification of lipid) from highly concentrated (100 g/L) microalgal suspensions (Chlamydomonas mexicana and Chlamydomonas pitschmannii). This integrated approach attained unprecedented total conversion efficiency (48–63%) and maximum total biomass utilization (77–86%) for both the microalgal strains with high yields of bioethanol (0.48 g-ethanol/g-carbohydrate), higher alcohols (0.44 g-higher alcohols/g-protein), and biodiesel (0.82–0.89 g-biodiesel/g-lipid) at suspensions of 100 g/L. Transmission electron microscopy was employed to visualize the changes in the intercellular morphologies before and after serial fermentations. Thus, this study demonstrates a cost-effective and energy-saving integrated approach for the holistic conversion of high-solid-loading microalgal biomass to produce high-density biofuels with minimum waste generation.

Landfill leachate (LL) are well known with low biodegradability and bio-methane potential (BMP) due to recalcitrant compounds and limited potential microorganisms. In turn, pretreatment step and addition co-substrate seem mandatory to improve the biodegradation and enhance the energy output. The present study was developed to assess the electrochemical oxidation (EO) and electrochemical conversion in low current density to improve LL bioavailability in anaerobic co-digestion (LL + Sludge) process. The enhanced biodegradability index: soluble COD (sCOD) and total volatile fatty acid (TVFA) of LL using EO pretreatment process were optimized under operational parameters: current density (10–40 mA/cm2), electrode gap (0.5–2 cm), and contact time (15–60 min). Specifically, the effects of EO pretreatment on anaerobic co-digestion reactors with high volume of LL under mesophilic temperature (37 ± 1 °C) in terms of operational performance, methane yield, Gompertz model and energy assessment were investigated in batch mode. An increase of sCOD (320–1165 mg/L) and TVFA (172–742 mg/L) were observed when the current density increased from 10 to 40 mA/cm2. The highest methane yield (0.2925 L/g sCODremoved) was obtained in anaerobic co-digested reactor fed with 35% LL (in volume). The EO pretreatment showed a significant reduction in the lag phase period for anaerobic co-digested reactors with high volume of LL. Furthermore, the high R2 proved the reliable prediction accuracy of modified Gompertz model to experimental data. Energy assessment showed an increase of 5.88–16.55 kJ/g VSremoved in anaerobic co-digested reactors compared to controls. The EO and anaerobic co-digestion showed as feasible and cost efficient method to enhance BMP and energy output from landfill leachate.

Extracting Alberta’s bitumen by SAGD requires a growing supply of steam, which is mainly generated from recycled produced water (PW). Traditionally, a warm lime softener (WLS), followed by walnut shell filter (WSF) and weak acid cation exchange (WAC) units have been employed to minimize the concentrations of silica, TOC, and hardness from PW. In this study, we enhanced TOC and silica removal in a WSF unit by modifying the surface of the walnut shell media. The walnut shells were modified by anchoring low mass percentages (e.g.

Phenolics were widespread in the effluents of coal gasification plants and oil refineries processes, while the impact of electrical stimulation on phenolics degradation in the combined biological processes remained unclear. Here, a novel anaerobic–aerobic–coupled upflow bioelectrochemical reactor (AO-UBER) was used to treat phenol-containing synthetic wastewater and simulated phenolic wastewater. The AO-UBER could treat phenolic compounds effectively via electrical stimulation. Phenol and total phenol removal efficiencies in the intermittently electrically stimulated system with a hydraulic retention time of 6 h were about 22.6% and 31.1%, respectively, higher than that in the biological system not exposed to voltage. The contribution of the aerobic cathodic chamber to the removal of phenolic compounds was higher than that of the anaerobic anodic chamber under the intermittent voltage application mode. High-throughput sequencing analysis indicated that electrical stimulation selectively enriched Acinetobacter, Cloacibacterium, Acidovorax, and Zoogloea in the phenol-containing synthetic wastewater treatment process, and Rhodococcus, Achromobacter, Chryseobacterium, and PSB-M-3 in the simulated phenolic wastewater treatment process. These results demonstrate that the AO-UBER under intermittent voltage application mode holds good potential for efficient phenolic wastewater treatment.

Biotechnological production of value-added products from sustainable resources such as C1 gas and lignocellulosic biomass is a practical solution for sustainable manufacturing. Methane and xylose derived from biogas and biomass can be promising carbon feedstock for chemical biomanufacturing due to their abundance and low cost. Herein, we developed a novel cell factory platform for highly efficient biosynthesis of chemicals from methane and xylose. By taking advantage of intrinsic high carbon flux through non-oxidative part of pentose phosphate pathway in ribulose monophosphate (RuMP) cycle of Methylotuvimicrobium alcaliphilum 20Z, we have metabolically engineered M. alcaliphilum 20Z to co-utilize methane and xylose as carbon and energy sources along with synthesizing of non-oxidative RuMP cycle-derived secondary metabolite, shinorine - a sunscreen material. Importantly, the final titer and yield of shinorine using the engineered methanotrophic biocatalyst were comparable to those from industrial workhorses. In order to confirm the versatility of this concept, the biocatalyst was applied for efficient biosynthesis of other bioproducts including 2,3-butanediol, acetoin, and 3-hydroxybutyric acid from methane and xylose. This work provides a novel and promising methanotrophic cell factory platform for chemical production from abundant methane and renewable xylose in a sustainable way.

This work studies cassava peel starch (CPS) potential as a replacement for commercial chemical coagulants for treating institutional wastewater since the CPS is highly biodegradable with non-toxic sludge and relatively locally available and cheap to obtain. The treatment of wastewater by CPS was optimized using response surface methodology (RSM), while the applicability of CPS was estimated based on techno-economic analysis (TEA). The alum (control), CPS, and mixed (alum and CPS) coagulants were optimized in terms of pH, dosage and settling time as independent factors. The optimal turbidity, total suspended solids (TSS), and chemical oxygen demand (COD) removal were recorded at pH 9, with 30 mg/L and after 34.34 min for alum at which the removal rates were 83.44%, 76.83% and 32.87%, respectively (R2 = 0.83). At pH 6.0, with 448.58 mg/L of CPS and after 43.23 min, the removal rate was 60.19% for turbidity, 57.79% for TSS, and 30.19% for COD (R2 = 0.86). At pH 8, with 4:1 ratio (CPS: alum) and after 60 min, the removal efficiency was 77.48%, 77.34% and 56.89%, respectively (R2 = 0.82). CPS’s efficiency is related to the presence of functional groups and elements, as determined by FTIR and XRF. The TEA shows that the CPS application is economically feasible, with a 34.49% internal return rate. The specific cost of pure CPS coagulant production is USD 1295.00 per ton, which is lower than the market cassava starch price of USD 3300.00 per ton. CPS provides an alternative method for chemical flocculation for wastewater treatment.

Biosolids from wastewater treatment plants is a crucial channel for the transfer of trace organic contaminants (TrOCs) from wastewaters to the soil, which necessitates the treatment of the biosolids prior to any application. The present study evaluated the effect of four different pre-treatment strategies on biosolids valorization and the subsequent removal of TrOCs during bioaugmentation with Bacillus subtilis. On analyzing the biosolids, out of the 72 TrOCs investigated, eight pharmaceuticals (total concentration of 157.2 ± 43.4 µg/kg), and two pesticides (total concentration of 18.8 ± 5.8 µg/kg) were detected. It was observed that when the biosolids was augmented with B. subtilis for 28 days, 52% TrOCs removal with a total suspended solids (TSS) reduction of 12% was achieved. In order to enhance the effect of aerobic digestion, four different pre-treatment strategies – alkali, ultrasonication, freeze-drying and enzymatic, were employed for biosolids management. Among these strategies, alkali pre-treatment showed the maximum TrOCs removal of 63% with 8% reduction in TSS, followed by ultrasonication, where the TrOCs removal was 32% with 5% TSS reduction. On comparing the combinational effect, the aerobic digestion of enzyme pre-treated biosolids showed an enhanced TrOCs removal of 90%, which also incurred TSS reduction of 18%, followed by the alkaline treated, freeze-dried and ultrasonicated biosolids. Thus, this study establishes B. subtilis aided aerobic digestion as an effective process for biosolids treatment and explains the impact of pre-treatment processes on TrOCs and TSS removal.

PHA production using a combination of mixed culture and carbon wastes has been demonstrated as a cost-reducing solution compared to the use of expensive pure culture process. Continuous research has been conducted with the aim to further reduce the production cost by simplifying the production scheme, as well as enhancing the performance of mixed culture in PHA production. Selection of the carbon feedstock and enrichment strategies needs to be essentially considered to obtain a culture enriched with PHA accumulators for a stable PHA production. Most of the studies implementing mixed culture process applied the feast-famine regime with periodical supply of carbon for culture enrichment. Results have revealed that the enriched culture showed a comparable performance with pure culture, in terms of PHA content (30–80%) and yield (0.4–0.8 g PHA/g S). However, a low productivity is the hindering factor to produce PHA at industrial scale by using mixed culture, which could be overcome by improvising the enrichment strategies. This review zooms into the evaluation of two step and three step processes in PHA production by utilising different feedstocks. Critical parameters to be considered for PHA production such as the suitable feedstocks, enrichment conditions, stability of the enriched culture and nutrient supplementation are being highlighted. The possible enrichment strategies that include uncoupled C and N supply and extended cultivation in overcoming the issue of low productivity are presented. The impact of different enrichment strategies on microbial community, characteristics of PHA produced as well as PHA production performance is worth investigating in future.

This study demonstrates the successful treatment of sugar industry wastewater (SIW) in a series of continuous electrochemical (EC) setup and adsorption bed along with economical assessment of the process. Batch study of EC process was performed to optimize the process parameter and the batch adsorption was also carried out to understand the adsorption capacity of the adsorbents. In continuous operation, SIW was passed through an EC reactor followed by a fixed low-cost adsorbent bed. Chemical oxygen demand (COD) and biological oxygen demand (BOD) are considered as characteristic parameters. The experimental findings suggest that single operational process is not efficient in the treatment of high initial organic load containing SIW. Only EC process removes over 60% of the COD at the normal conditions in continuous operation (initial COD 3000 mg/L, 1.5 cm electrode gap, pH 7, 8.92 mA/cm2 current density, and flowrate 8 ml/min). While coupling of EC and adsorbent processes was found more efficient and removed ~92% COD from the SIW. Further, the EC treatment enhances the biodegradability Index (BI) of treated SIW, and adsorption process using bagasse-based fly ash (BBFA) efficiently removes excess BOD of EC treated SIW. At optimum conditions (8 ml/min) in continuous flow process, the treatment cost was found to be 1.23 $/kg CODR and 0.85 $/kg CODR for EC and EC+ adsorption process, respectively.

Textile dyeing sludge (TDS) is a highly toxic solid waste whose co-pyrolysis can jointly achieve waste reduction and recovery of value-added products. This study aimed to fill the knowledge gaps about the co-pyrolysis mechanisms and products (gases and solids) and their dynamics in response to the atmosphere type, blend ratio, heating rate, temperature, and their interactions. The high temperature pyrolysis (>720 °C) in the CO2 atmosphere appeared as the best option for the waste reduction. The (co-)pyrolysis in the CO2 atmosphere enhanced S-containing air pollutants, CO, and CH4 but reduced NOx. The interaction effect between TDS and durian shell (DS) residues promoted the productions of furan and acid compounds and inhibited the productions of aromatic, phenolic, and N-containing compounds. The atmosphere type affected the type and strength of the reactions involved in the production of biochars. Our findings provide practical and new insights into the optimization of energy generation, product recovery, and emission control during the (co-)pyrolysis.

It is firmly established that contemporary building materials and indoor furnishings are associated with elevated concentrations of formaldehyde in indoor air, representing a hazard to human health. To mitigate this issue, formaldehyde and other pollutants in indoor air are removed via air conditioning systems fitted with appropriate filters. Based on positive results from earlier, relevant research, this study investigates the use of air conditioning filters treated with chitosan as potential eco-friendly absorbents for removal of formaldehyde, a significant indoor air pollutant. The filter is sprayed with different dosages of chitosan, in accordance with our previous work [8]. Removal rate and adsorption of formaldehyde are calculated for the health risk assessment. After twenty-four hours testing, the results showed the averaged concentration of formaldehyde is 1.146 ppm, 0.714 ppm, and 0.084 ppm with chitosan dosage of 2.6 mg m−2, 5.3 mg m−2, 8.0 mg m−2, respectively. The averaged reduction of formaldehyde concentration is 64.9%, 80.0%, and 96.0%; the averaged absorption of chitosan on formaldehyde is 0.167 mg, 0.204 mg and 0.271 mg for chitosan dosage of 2.6 mg m−2, 5.3 mg m−2, 8.0 mg m−2, respectively. The risk characterization figures without spaying chitosan are 2.94, 2.65 and 7.07 times higher when compared with the same figures associated with filters treated with 2.6 mg m−2, 5.3 mg m−2, and 8.0 mg m−2 of chitosan. This study finds that chitosan has strong potential as a commercial adsorbent. Increasing the amount of chitosan applied to the filter substrate improves the efficacy of the absorbent and further reduces the indoor formaldehyde concentration and the associated carcinogenic risk.

Orthophosphate (PO4-P) removal and recovery from municipal wastewater were investigated in a 10 m3/day hybrid anion exchanger (HAIX) demonstration plant. To date, HAIX resins have been investigated for PO4-P removal at laboratory scale with promising results but there is a need to investigate the application of the technology at larger scale, over extended operation whilst establishing an efficient regenerant management solution. The HAIX removed an average of 6 mg PO4-P /L to >0.3 mg PO4-P/L, within 430 bed volumes, with a capacity of 4.1 mg PO4-P/g resin. To manage the regenerant (NaOH 2%) efficiently, this was reused up to 8 times, reaching 785 mg PO4-P/L, but the adsorption capacity was compromised, and it decreased to 1.5 mg PO4-P/g resin. By adding calcium hydroxide to the saturated NaOH, 95% of the PO4-P was recovered as hydroxyapatite, and at the same time the regeneration effectiveness was re-established, as

Granular activated carbon (GAC) has been reported to benefit anaerobic digestion systems by stimulating direct interspecies electron transfer (DIET) as an alternative to interspecies hydrogen transfer (IHT). Conventional up-flow anaerobic sludge blanket (UASB) reactors typically have GAC settled at the bottom of the reactor, limiting the contact between biomass and GAC. This study demonstrated a modified UASB reactor that fluidizes GAC by encaging GAC in plastic carriers. Enhanced performance was achieved with respect to methane production and COD removal at an organic loading rate of 1500 g COD/m3/d under the temperature of 20 °C using the self-fluidized GAC configuration; with the methanation rate increased from 0.33 ± 0.08 g CH4-COD/g influent COD in the non-GAC reactor, to 0.66 ± 0.02 g CH4-COD/g influent COD in the GAC-only reactor, and further increased to 0.77 ± 0.02 g CH4-COD/g influent COD in the self-fluidized GAC reactor. The concentrations of medium-chain acyl-homoserine lactones increased in the GAC-amended reactors, potentially associated with the promotion of syntrophic interactions between bacteria and archaea. Batch tests were performed for syntrophic propionate degradation under hydrogen-inhibition conditions, and showed that microbial consortium enriched in both GAC amended reactors can overcome hydrogen inhibition. Further microbial community analysis unveiled a variation in spatial distribution in the GAC enriched microbial consortium (including DIET indicator microorganisms such as Geobacter and Methanosarcina) based on the location of GAC in the reactors. This study demonstrated an improved GAC amendment strategy in UASB reactors to facilitate biomethane recovery from wastewater anaerobic digestion.

Selective catalytic reaction (SCR) is widely used in flue gas denitrification to convert NOx air pollutants into N2 and H2O in the presence of SCR catalyst, but arsenic poisoning causes serious deactivation of SCR catalyst and produces a huge amount of spent SCR catalyst worldwide. Therefore, the regeneration and recycling of spent SCR catalysts are of great necessity for the sustainable flue gas denitrification due to the very high cost of replacing commercial catalysts. Nowadays, a combination of alkali treatment and acid washing is usually used to regenerate spent SCR catalysts. However, high residue of As strongly inhibits the catalytic activity of the regenerated products. In this study, an active bioleaching liquor produced by Acidithiobacillus thiooxidans as indirect bioleaching was attempted to deeply remove As from the regenerated product for the first time. The results showed that bioleaching resulted in maximal As removal of 53.1% even at a high pulp density of 10% to harvest a minimum As residue of 174 mg/kg below the limiting value of 200 mg/kg; whereas H2SO4 leaching attained 6.7% As removal and as high as 345 mg/kg of As residue. A stronger activation of the regenerated products simultaneously occurred with the bioleaching. A great amount of cysteine in the bioleaching liquor secreted by the microbe accounts for both the enhancement of As removal and strong activation of the product. A novel mechanism is proposed to explain the excellent As removal by the indirect bioleaching based on nucleophilic attack of the sulfhydryl groups in cysteine.

A green organic waste potato residue (PR) was double-modified for synergistic sludge dehydration-detoxification. In this work, the properties of modified product (signed as D-MPR), and its crucial effects on sludge properties were investigated. Besides, role of D-MPR in sludge co-dehydration/decontamination was also explored. Results showed that etherification and grafting modification produced D-MPR of high-performance. It largely and synergistically reduced sludge volume and toxicity by adjusting distribution of bound water, microbes, organics, and heavy metals in sludge. Adding 12–15‰DS (mass of dry solids in sludge) of D-MPR, about 94% of bound water was removed from sludge, and few intracellular bound water was left in sludge. Besides, approximately 90.53% of bacteria, 73% of dissolved organics and 54.46% of total risky heavy metals were removed. As the main toxic substance in sludge, 92.41% of CdF1/F2/F3, 90.67% of CrF1/F2/F3, 55.92% of CuF1/F2/F3, and 64.56% of ZnF1/F2/F3 were removed in the chelation process caused by D-MPR and organics. However, 54.17% of PbF1/F2/F3, 70.08% of NiF1/F2/F3, and 65.44% of AsF1/F2/F3 were removed by flocs sweeping. Moreover, the Partial Least Square Regression (PLSR) model showed that, by enhancing Binding Energy (Eb) of bound water, reducing Fractal Dimension (DF) of sludge flocs and humic acid content could highly reduce sludge quality and poisonousness. Particularly, compared with the commonly used method such as Fenton processing, freezing and thermal treatment, the method is cheaper, more energy-conserving, more effective, and more environmentally friendly.

Acid mine drainages (AMD) are the most harmful and chemically complex aqueous waste produced by the mining industry, causing contamination of fresh water sources, affecting human communities and the environment surrounding the mine facilities. Nowadays, AMD treatments use a high amount of reagents that produce a considerable quantity of waste, limiting the opportunity for recovering valuable metals. AMD typically can contain high quantities of copper that could be potentially recovered as a saleable product. Accordingly, this study proposes a novel combination of metal sulfide precipitation with membrane microfiltration process to clarify and separate those previously formed metal sulfide, focused on enhancing the copper recovery and the performance of clarification, evaluated in terms of turbidity of treated solution and separation rate. Three synthetic AMD were assessed, varying the copper content in a mono tubular ceramic membrane of 0.14 µm pore size. Results were promising: flux values were higher than 0.1 L/m2s, at least one order of magnitude higher with respect to other matrices. Copper recoveries were closer to 100% and turbidity values in the treated solution were lower than 2 NTU for sulfide stoichiometric dosages of 120%. Hence, this method could be an excellent alternative to efficiently recover copper from AMD.

With increasing awareness in environmental protection from the world, traditional pretreatment methods for textiles, which entail high costs and cause severe pollutions, can no longer meet the requirements of green and sustainable development in textile industry. Therefore, to explore a new pretreatment method to overcome those drawbacks is of great importance. In this work, green and environmentally friendly method was developed in supercritical carbon dioxide fluid to pretreat cotton gray fabric for removing various impurities with one step and one bath, by utilizing an 18-crown-6 phase transfer system. Various process parameters, such as the pH value of buffer solution, the dosage of phase transfer catalyst, hydrogen peroxide, buffer solution, and the system temperature, pressure, treatment duration, were investigated and optimized by employing the weight loss percent and the capillary rise height as assessment index. The obtained results show that the developed alkali-hydrogen peroxide one-step method involving the 18-crown-6 phase transfer system in supercritical carbon dioxide exhibits a good feasibility for the removal of various sizing agents and other impurities from cotton fabric, and a satisfactory pretreatment performance and efficiency were achieved. The pretreatment parameters showed an important and various effects on the pretreatment efficiency of cotton substrate during a phase transfer oxidative one-step process in supercritical carbon dioxide. Moreover, a phase transfer oxidative one-step process was also recommended for cotton gray fabric pretreatment in supercritical carbon dioxide, by achieving a fabric weight loss at 6.21% and a satisfactory capillary rise height at 8.0 cm under an optimized condition. Additionally, an oxidative one-step pretreatment mechanism by employing 18-crown-6 to phase transfer reactive species for cotton gray fabric in SCF-CO2 was further supposed.

Graphical abstract, One of the promising drug targets against COVID-19 is an RNA-dependent RNA polymerase (RdRp) of SARS-CoV-2. The tertiary structures of the SARS-CoV-2 and SARS-CoV RdRps are almost the same. However, the RNA-synthesizing activity of the SARS-CoV RdRp is higher than that of the SARS-CoV-2 RdRp. We performed molecular dynamics simulations and found differences in their dynamic properties. In the SARS-CoV RdRp, motifs A–G, which form the active site, are up to 63% closer to each other. We also observed cooperative domain motion in the SARS-CoV RdRp. Such dynamic differences may cause the activity differences between the two RdRps.

Aerobic digestion is widely used to stabilize and reduce waste activated sludge in the decentralized wastewater treatment plants, but it would deteriorate sludge dewaterability. Thus, improving the dewaterability of aerobically digested sludge (AeDS) is of vital significance for sludge disposal and management. This study investigated the possibility of zero-valent iron (ZVI)/sulfite system for promoting the dewaterability enhancement of AeDS. The results showed that ZVI/sulfite system was favorable to improve the dewaterability of AeDS. The highest reduction of capillary suction time and the lowest value of water content of sludge cake were (81.7 ± 3.6)% and (69.3 ± 1.2)%, respectively, under the optimal experimental conditions (reaction time = 60 min, ZVI = 0.9 mmol/g volatile solids (VS), sulfite = 1.2 mmol/g VS, pH = 6, and purging air). Compared to Fe2+/sulfite and Fe3+/sulfite systems, ZVI/sulfite system was more favorable to improve the dewatering performance of AeDS. The results also demonstrated that the main radical species in ZVI/sulfite system were sulfate radical and hydroxyl radical, which could effectively degrade tightly-bound extracellular polymeric substances and then led to the release of bound water and the increase of zeta potential. Consequently, the dewatering performance of AeDS was obviously enhanced. Additionally, the reusability of recovered ZVI in ZVI/sulfite system for AeDS conditioning was satisfactory.

International audience; In practice, the elastic lateral-torsional buckling of doubly symmetric I-section steel members is analyzed assuming free warping at supports. However, welded stiffeners, bolted end-plate connections or column base plates maintain elastically the opposite flange out-of-plane rotations and thus induce substantial warping restraints.This paper proposes analytical formulations for the evaluation of the elastic critical bending moment for lateral-torsional buckling of beams taking into account warping restraints at supports. Assuming series of displacement and rotation fields containing one or two terms, the energy method permits to derive expressions of the critical bending moment under constant and linear distribution of the bending moment. A single expression of the warping coefficient kw is proposed whatever the shape of the bending moment diagram. The factor C1 can be conveniently calculated by multiplying two coefficients that depend on the shape of the bending moment diagram and on the warping restraint stiffness, respectively.Finite Elements analyses of beams with warping restraints at supports have been performed considering a beam element model developed with LTBeamN and a shell element model created in ANSYS. The analytical model is in good agreement with the numerical results obtained by the two finite element models.

The synthesis of metallic Nanoparticles (NPs) has gathered utmost interest over the past decades thank to their distinctive properties that build them applicable in several fields further as including science and technology. This main methods utilized in their synthesis are non-environmental friendly. This review paper describes the green methods within the synthesis of biogenic NPs further as their mechanisms involving various plant extracts which are non toxic, environment friendly and value effective. The natural plant extracts contains metabolites like flavonoids, terpenoids, polyphenols, alkaloids, etc which acts as both reduction and stabilization agents for synthesizing biogenic NPs with desired shape and size. During this review paper the employment of assorted plant extracts additionally the employment of bacteria, fungi, proteins within the biogenic synthesis of NPs has been delineated shortly. Ultimately the importance and applications of biogenic NPs has also been expressed.

The primary objective of university education is to provide students with the required information and skills to enable them to make a successful contribution to the national development effort. In order to evaluate the level of expertise and skill of students, this preparation includes frequent examination and appraisal in the form of tests. Manual exams are carried out by most universities; Post Graduate and Under Graduate in India. Due to multiple uses made of the outcomes of the students, these examinations have high stakes. Consequently, the experiments became subject to different types of malpractice. Test malpractice affects the success of students in exams and leaves the scores/grades earned inaccurate, hence a challenge to examination bodies and the nation's education system (India). These are all disturbing signs that pose a danger to the nation. Examination malpractice has eaten deep into the Indian culture of education. Therefore, the object of this paper is to explore the problem of examination malpractice in India. The paper covered relevant measures, procedure setting/implementation and suggestions for this action. And finally, a model is proposed to stop malpractices in the examination. This IoT based model is used for detecting any metallic object or object in a range more than normal IR proximity sensor range. The block diagram of proposed model and circuit diagram for that model discussed in detail. This proposed model may be used for any investigation in the universities examinations.

Smart materials have played significant contribution towards the development of buildings. There are various smart materials which can change their properties and behavior under the influence of external catalyst or stimulus. Such materials are changing the face of traditional engineering materials. Smart materials can be utilized individually as well as it can be incorporated with existing materials to enhance their desirable properties. Smart materials are widespread across all the domains of human inventions due to its multidisciplinary applications. Some of these materials are relatively new while some are being used from a very long time. Hence it suffices to say that the recently developed smart materials still require research. The general classification of smart material is illustrated in this review paper. The paper intends to identify the various types of available smart materials and also illustrated the application of such materials in the various fields of civil engineering. Further, the potential benefits and downsides are also discussed along with their applicability under different conditions. Some innovative materials are also discussed which can bring potential revolution in the construction industry. The impact or the benefits related to sustainability also discussed in this review paper.

This paper depends on safeguarding newborn children who have fallen into the bore well. A bounty kid demise reports have been accounted for up until this point. In India, for recent days’ individuals are confronting a troubled pitiless circumstance like kids have fallen in the bore well and struck in the opening which is revealed and getting caught. Salvage of caught kid from bore well is the hazardous and troublesome procedure when contrasted with different mishaps. Because of sparseness of water level, bore well are burrow to more profundity. The premise of this undertaking is to protect the baby. The salvage is finished by burrowing a parallel pit, which takes over a day and even have not discovered a certified outcome. The high purpose of this task is that the kid will be protected before it arrives at high profundity, which depends on correspondences utilizing Infra-Red Signals. At the point when the IR signal, put 2 in. oppositely inside the surface of the bore-well, but if breaks because of some blocking paper, a ringer begins rings as some alarm of a mobile. After a stake which is set as couple of ft. lower inside the surface bore well, shuts it so as to keep the babies safe from falling further inside any kind of well. Moreover CCTV cameras can be utilized for ceaselessly screen so the kid’s present situation. This framework uses a powerful LED that goes inside like a light source so light force inside these gap would be very less. These mishaps are significantly found in agrarian bore-well. The different dangers related to the salvage of children can be limited by utilizing this framework. In this elective situation, there won't be any necessities to dig the hole in parallel with the underground bore well. These kids can be spared inside a brief timeframe with no troubles.

In the recent years the utilization of cloud to store and process the big data is increased rapidly. Security is the major concern faced by the big data in cloud environment. This paper proposed the authentication scheme for preserving the security and privacy of the big data in cloud environment. This paper considered the medical big data processing from the telemedicine system as the big data. The medical big data consists of huge volumes of medical records which are stores in the cloud. In the proposed mechanism follows mutual authentication and performs encryption operation between user and cloud environment. The proposed authentication mechanism has less computational load compared to the existing algorithms.

This paper is a unique effort to resolve the scaling issues of machine learning using the multi-node environment of Big Data. For this purpose, it incorporates the concept of machine learning with big data. Machine learning is a branch of Artificial Intelligence which trains the computers to learn without being explicitly programmed. Machine learning works on the development of computer programs and software that work according to the input dataset. In machine learning, classification is used to identify the class of instances. In this the category or class or a group provides the new observation to which it belongs on the basis of the training dataset. Training datasets contain those instances whose class is already known. An algorithm that implements classification is known as a classifier. The main aim of this paper is to evaluate how different classifiers work on two different datasets, one is a real time dataset of MP Election nomination (2018), while the other is a standard Breast Cancer dataset, released by University of Wisconsin (1995). There are various classifiers available like Decision Trees, K-Nearest Neighbors, Support Vector Machine, Logistic Regression, Naive Bayes etc. Different classifiers work differently on different datasets, giving different accuracy according to the kind and the size of the dataset. So we have used different classifiers for our work. When we were applying machine learning classifier on a real-time dataset, i.e. MPSEC dataset, Accuracy goes down. Similarly, these classifiers apply to Standard Breast Cancer dataset then results show outstanding accuracy. This research work shows the exciting patterns to study the case of a real-time and standard dataset using different machine learning classifiers with a combination of big data. This research work also incorporates the concept of parallelization using a multi-nodes environment which is able to deal with scalability issues.

Road surface irregularities not only has an impact on consistency of road, but also affects driver safety, automobile mechanical stability, and fuel consumption. To order to evaluate road roughness and spot potholes, many solutions have been suggested to remotely track the road surface quality. Some of these methods use an embedded mobile accelerometer to take a crowd sensing view to feel the surface of road. Although crowd sensing has various advantages such as ubiquity and less cost, it has some sensitivity to the problems generated by structures made by human, actions of the driver, and characteristics of the road surface which cannot be identified road anomalies. For this purpose, this paper suggests method of deep learning which helps us (a) to identify the different types of surface of road and (b) to differentiate potholes automatically from destabilizations in the crowd sensing-based application sense arising from speed bumps or driver behavior. This paper study and implement different deep learning frameworks in particular: convolutionary neural networks, LSTM networks, and computational structures for reservoirs. The tests were performed using knowledge from the real world, and the results revealed good precision in solving both of the problems.

In this research paper, CBIR algorithm development using RGB histogram-based block contour method to improve the retrieval performance is presented along with the simulation results. CBIR to extract the visual content of an image automatically like color, texture, size, direction, distance, nearness or its shape using HSV colour RGB histogram & block contour methods is proposed here in this paper. The work presented in this paper is a new methodology of the picture retrievals by the combination of different parameters of the query image with the help of RGB histograms & the block contours. Simulations are carried out in the Matlab environment and the simulation results are observed. The CBIR based system is going to be tested using different types of test images for varieties & finally the nearest test outcomes will be got & be tabulated neatly. Here, in this proposed work using different sizes of the blocks & the no. of characteristics & the time obtained for extracting those realistic parameters could be found out & also other parameters such as the recalling, precision, characteristics were calculated and compared with existing systems. The precision and recall are used to calculate the performance of the designed system. The results presented gives precision values & the values of the recall parameter of the developed & existing CBIR systems, which shows the efficacy of the proposed methodology that is superior. Here, the observation is – the developed methodology will be highly unique, its performance will be more superior to the existing systems. Finally, to conclude, it could be iterated that this contributory work was developed to show about the RGB histogram & block contour concept involvement to extract the different features of the images and carry out the performance of system (retrieval). Finally, the results of the simulation gives the improved performance of the system (retrieval) over the others, thus showing the profoundness or the effectiveness of the research work done.

In this paper Telematics and employments of Telematics in vehicles is presented. Advancement is developing every year and is used by planners of the structure in various edges for the duration of regular day to day existence. Telematics system is making in different perspectives. Apparently it gives a lot of organizations in human lives. It makes life snappier and lessening setbacks in vehicle. Telematics data gives the reason to perceiving how far, how rapidly and underneath what conditions an individual drives, similarly as a foundation for logically propelled data showing improvement. This limit is developing new and innovative things that even more correctly esteem peril and attract beneficial new customers. By then, it explains how this structure works. It is like manner tends to the favored viewpoint and block of the system. This paper in like manner fuses the issues related to the telematics structure. Finally, it will see logical examination and wrap up this paper.

Over a last few decennary free space optical communication (FSO) have become more interesting alternative to the radio frequency for communication. The FSO is emanating technic that have been found the applications in different place of shorter & longer distance communication. The any technology, of FSO has been worked that much good in the several applications rather than other. In this paper we will examine FSO from different angles. The analyses this paper accompany of the technology has shown that FSO technologies inherent strengths and it lack the use of in ground cables which make it much expeditious & cheaper to installing, and the facts that will operates in the unlicensed spectrum, it will be removed & installed elsewhere and it has relatively high bandwidth. Specifically, this paper found that because FSO uses air as a communication medium, its performance & reliability are restricted by fog, rain, snow and dust. Maximum range of FSO may be in kilometers only. The applications that FSO technology seems most suited to is clear this pap rather and short distance connection establishment, like interrelation to broadband networks backbone & backbone links bet this papered building in the metropolitan area networks (MAN) or the campus area networks (CAN).

This paper reports at Augmented Reality (AR) as a field, where a real time integration of a 3 dimensional real environment and the virtual 3D objects. This paper explains the applications related to medical, engineering, simulation, route planning, entertainment, and military that have been discussed. Two of the greatest challenges in constructing efficient augmented reality or AR systems are registration errors and sensing errors. In this paper, authors summarize current practices to overcome these issues. A discussion of future strategies and the areas requiring more study is done. Moreover, this survey can serve as an initial point for anyone those who are interested in researching and/or using augmented reality. This is because peoples are at a stage wherein adoption of technologies based on augmented reality for enhancement of our perception and to help ourselves sense our environment in a new and an enriched way is the need of the hour.

Blockchain has become one of the most developing technologies in our country. Blockchain technology is a decentralized, distributed ledger that records the sources of digital assets. Electronic Medical Record (EMR) accommodates patient’s medical history, which has been carried out by a Physician or Doctor in a particular clinic or hospital or Healthcare center. Whereas, Electronic Health Record (EHR) holds patient’s entire health history, including immunization plans, diagnosis, lab reports, inoculation schedule, etc.,. This feature empowers the usage of Health IT in a more secure way with the amendment of blockchain technology. These records are maintained smart contract between the patient and the healthcare sector. In both EMR and EHR, the patient is the owner of his own data. This paper incorporates the features of blockchain technology to provide a collaborative work on Electronic Medical Records (EMRs) and Electronic Health Records (EHRs) and it concentrates highly in diabetes as it has a sharp magnification in current world. Though it is tedious to implement this EHR all over the country, this paper works for its implementation especially in the domain of diabetes.

Smart contracts are a vital component of applications being built by blockchain or distributed ledger technology. Smart contracts consists of computer code that composed set of rules agreed upon by the involved parties. When these predefined conditions or rules are satisfied by the transactions initiated by parties, the smart contract executes itself to complete the transaction. Normally, while performing transactions with agreements involving multiple parties, a third party have to be involve to verify all the information, which makes it complex and time consuming process. Smart contracts simplify this process by eliminating the third party and automating the process, enabling the stakeholders to perform transactions directly with each other. Smart contract itself is replicated among multiple nodes of a blockchain there by giving benefits of immutability, security and permanence. Most smart contracts are written in Solidity programming language due to its simplicity and conciseness. Attackers are attracted by the popularity of Solidity language and its vulnerability possibilities. For example, in the 2016 year, 60 million US dollars was theft by Decentralized Autonomous Organization (DAO) attack due to vulnerabilities present in smart contracts. There are few existing tools and papers on this area to find vulnerabilities on smart contracts but taking more time to predict. Thus, this paper presents different Deep learning techniques with satisfactory results to identify smart contract vulnerabilities which are Re-entrancy, Denial of Service (DOS) and Transaction Origin using binary, multi class and multi label classification techniques.

The extended traffic volume and backing require sufficient and solid pavements, which controls the black-top difficulty. A huge amount of assessment deal with the Stone Mastic Asphalt (SMA) gives a difficult surface course. Various down to earth tries are made to adjust SMA mixes with built strands and polymers. Directly a day's plastic waste is the key issue for an eco neighbourly legitimate condition. In this assessment work, plastic waste like Low-Density Polyethylene (LDPE) fundamental food thing sacks are used as an additional substance to diminish the leakage at high temperatures during limit, transportation, circumstance, and compaction to improve the interfacial security among sums and spread. Like this, the mix plan of SMA is executed with Marshall mix structure procedures. Marshall Stability Test finishes this testing research. The all out level of the SMA mix and the folio content was 5.5%, 6%, 6.5% by weight of genuine and plastic waste used was 5%, 10%, 15% by weight of bitumen. This current paper's objective is analyzing Objectives, advancement material piece, economy achieving by using waste materials and inclinations over the mixes. For sure, even in this work, we applied simulation investigation, as you can see in this paper.

Mobile Ad-hoc networks (MANET) is a collection of nodes of wireless connectivity. In Mobile Ad hoc Network (MANET) all the mobile nodes are requiring restricted battery capacity. Because of the changing nature of network the sudden communication link breakage happens. Hence the possibility of data loss is more. Efficient utilization of energy and lossless transmission are the important issues in MANET. This paper proposes a new Trust based Efficient Energy Balanced Less Loss Routing (TER) Protocol for MANETS. This protocol improves the network performance by properly choosing the intermediate forwarding nodes. The Source Node picks only single of its neighbors as its next hop node by using Efficient Parameter (EP). The EP is calculated from the residual energy, distance, Occupied Queue space, the velocity of that node. The node using maximum EP is nominated as the succeeding node. This protocol reduces the number of channeling messages and hence reduces the path-finding Overhead of the network. It lessens the chance of data loss and hence improves throughput and Packet Delivery Ratio. This protocol adds trust to the selected node. In this paper, we do the simulation in ns-2 simulator and the performance is measured by with performance parameters like Routing Overhead, Packet Delivery Ratio, Throughput, End to End Delay and Average energy consumption.

In recent decades, the requirements for higher eco-friendliness in the car segment have persuaded the expanded utilization of design in lightweight mixes of multi-material. It has unavoidably prompted difficulties in joining base materials (for example, low, medium, and ultrahigh quality) where magnesium combinations, steels, and aluminium compounds are joined. Simultaneously, every one of these materials recommends fluctuating execution and superior properties for different segments in various areas of novel design. Accordingly, these base material blends will unavoidably be welded, which presents significant difficulties because of their contradiction during friction welding techniques utilized in vehicle fabricate. This paper discussed current advancement in friction welding procedures for joining the various parent materials and explains welding parameters controlling the joint quality. Be that as it may, financially savvy and dependable joints of lightweight amalgams (for example, aluminium) and steel will need significant advancement and contemplation. The reason for the current survey paper is to evaluate the status of friction welding of different base materials of vehicle manufacturing alloys, with explicit thoughtfulness regarding the future development, vehicle manufacturing sector, impediments, and difficulties.

The main purpose of this paper is to observe the effect PV variation of solar temperature and irradiance on different conditions and on the inverter output for a grid-connected system. Majorly temperature& solar irradiation effects the performance of a grid connected inverter, also on the photo-voltaic (PV) electric system. The simulation based study was carried out in order to evaluate the variation of inverter output with the variation of solar temperature and irradiance with the variation in climate. The analysis of Grid-connected inverter and their performance at various seasons and conditions is investigated. Solar power plant for a year. In solar power plant efficiency of inverter is also considered to calculate overall losses so, the inverter efficiency and plant performance are considered in this paper using MAT Lab software. In summer season the inverter performed efficiency is decreased because of peak temperature value and slightly increased with the increase in irradiance.

The power transmission tower’s ground electrode defect will affect its normal current dispersion function and threaten the power system’s safe and stable operation and even personal safety. Aiming at the problem that the buried grounding grid is difficult to be detected, this paper proposes a method for identifying the ground electrode defects of transmission towers based on single-side multi-point excited ultrasonic guided waves. The geometric model, ultrasonic excitation model, and physical model are established, and the feasibility of ultrasonic guided wave detection is verified through the simulation and experiment. In actual inspection, it is equally important to determine the specific location of the defect. Therefore, a multi-point excitation method is proposed to determine the defect’s actual position by combining the ultrasonic guided wave signals at different excitation positions. Besides, the precise quantification of flat steel grounding electrode defects is achieved through the feature extraction-neural network method. Field test results show that, compared with the commercial double-sided excitation transducer, the single-sided excitation transducer proposed in this paper has a lower defect quantization error in defect quantification. The average quantization error is reduced by approximately 76%.

This study examines how scientists respond to visual design in scientific communications. Specifically, we determine the impact of visual design on the Graphical Abstract (GA), an overview figure that attracts potential readers and visually summarizes what a paper is about. We show that GAs designed in accordance with classic visual design principles significantly enhance readers’ first impressions of a paper. Well-designed GAs make papers seem more interesting, more clearly written and more scientifically rigorous. These results confirm that visual design enhances rather than detracts from the perception of intellectual and scientific competence.

In the titanium dioxide industry, there is a lack of a low-cost and high-efficiency treatment method for chloride containing tail gas. In this paper, the removal of HCl from the titanium dioxide industry by gas cyclone-liquid jet separator was studied, while Ca(OH)2, Na2CO3, NaOH solution, and water were used as absorbents. This paper investigated the influence of gas cyclone-liquid jet separator’s various process parameters on the removal rate of hydrogen chloride gas. The mechanism of mass transfer in the process of removing hydrogen chloride was discussed, and the effect and feasibility of HCl gas removal in the gas cyclone-liquid jet absorption separator were studied. The results showd that the removal efficiency of hydrogen chloride maintained above 95%, up to 99.9%, and the total mass transfer coefficient reached 0.28 mol·m-3·s-1·kPa-1. Under the same conditions, the absorption effect and total mass transfer coefficient of weak basic absorption liquid can be greatly improved by increasing the flow rate of absorption liquid, but the absorption effect and total mass transfer coefficient of strong alkaline absorption liquid can’t be improved obviously. The larger the inlet gas volume, the higher the gas concentration, the lower the absorption efficiency and the lower the total volumetric mass transfer coefficient.

This paper summarizes the submissions to a recently announced contact-mechanics modeling challenge. The task was to solve a typical, albeit mathematically fully defined problem on the adhesion between nominally flat surfaces. The surface topography of the rough, rigid substrate, the elastic properties of the indenter, as well as the short-range adhesion between indenter and substrate, were specified so that diverse quantities of interest, e.g., the distribution of interfacial stresses at a given load or the mean gap as a function of load, could be computed and compared to a reference solution. Many different solution strategies were pursued, ranging from traditional asperity-based models via Persson theory and brute-force computational approaches, to real-laboratory experiments and all-atom molecular dynamics simulations of a model, in which the original assignment was scaled down to the atomistic scale. While each submission contained satisfying answers for at least a subset of the posed questions, efficiency, versatility, and accuracy differed between methods, the more precise methods being, in general, computationally more complex. The aim of this paper is to provide both theorists and experimentalists with benchmarks to decide which method is the most appropriate for a particular application and to gauge the errors associated with each one.

In this paper, dynamic similarity conditions are derived for discrete element simulations by non-dimensionalising the governing equations. These conditions must be satisfied so that the numerical model is a good representation of the physical phenomenon. For a pure mechanical system, if three independent ratios of the corresponding quantities between the two models are set, then the ratios of other quantities must be chosen according to the similarity principles. The scalability of linear and non-linear contact laws is also investigated. Numerical tests of 3D uni-axial compression are carried out to verify the theoretical results. Another example is presented to show how to calibrate the model according to laboratory data and similarity conditions. However, it is impossible to reduce computer time by scaling up or down certain parameters and continue to uphold the similarity conditions. The results in this paper provide guidelines to assist discrete element modelers in setting up the model parameters in a physically meaningful way.