Super Water Research Articles

A metal-nano GO frameworks/PPS membrane with super water flux and high dyes interception

Nano graphene oxide (NGO) particles with the multiscale structure were prepared, and divalent metal cations (Ca2+, Cu2+ and Mg2+) were employed as crosslinking agents to closely stack nano NGO particles both on the surface and in the pore-channels of poly(p-phenylene sulfide) (PPS) membrane support forming the novel filter layer which had the similar structure with metal-organic frameworks (MOFs) through electrostatic forces and coordination bonds. Metal-NGO framework exhibited the similar MOFs structure with permanent nanoscale cavities and open channels, and Metal-NGO frameworks modified PPS membrane displayed the most excellent H2O permeability and high dyes rejection performance. In Metal-NGO/PPS hybrid membrane, Metal-NGO frameworks were closely attached with PPS membrane surface though the coordination between metal ions and -S- of PPS. Compared with the transversal interlayer molecular transport channel of conventional GO membranes, Metal-NGO frameworks modified PPS membrane possessed the shortest permeable channel, highest pore-opening rate, continuous GO transmission layer and multistage structure of nano channel, endowing the membrane with ultrafast water molecular transport rate and high pure-water flux of 3109.5 LMH/MPa. Furthermore, the prepared Metal-NGO frameworks modified PPS membrane exhibited the high rejection rate at 99.9% in RB rejection.

Characteristics Analysis of Roof Overburden Fracture in Thick Coal Seam in Deep Mining and Engineering Application of Super High Water Material in Backfill Mining

With the development of deep mining, the mining pressure on the working face is increasing, the failure height of thick seam roof is increasing, and the failure characteristics of roof are becoming more complex. The cracks in the overlying strata of the roof are greatly increased and activated by mining influence, which increases the impervious threat of the roof. In order to solve this problem, the failure stress model of thick coal seam roof was established; the 1308 working face of Yancheng Coal Mine was taken as the engineering background, and the FLAC3D numerical simulation software was used to simulate the formation failure process of 1308 working face with the threat of water permeability; the drilling section water injection test method was used to measure 1308 working face; High water material is used as raw material to fill 1308 working face. The results show that: (1) the failure height of overlying strata is calculated more accurately by mechanical model, and the failure characteristics are analyzed; (2) the failure height of overlying strata calculated by numerical simulation is smaller than that calculated by theory; (3) the problem of serious roof caving in thick coal seam can be effectively alleviated by filling with super-high water material.

Multi-objective Bayesian optimization of super hydrophobic coatings on asphalt concrete surfaces

Abstract Conventional snow removal strategies add direct and indirect expenses to the economy through profit lost due to passenger delays costs, pavement durability issues, contaminating the water runoff, and so on. The use of superhydrophobic (super-water-repellent) coating methods is an alternative to conventional snow and ice removal practices for alleviating snow removal operations issues. As an integrated experimental and analytical study, this work focused on optimizing superhydrophobicity and skid resistance of hydrophobic coatings on asphalt concrete surfaces. A layer-by-layer (LBL) method was utilized for spray depositing polytetrafluoroethylene (PTFE) on an asphalt concrete at different spray times and variable dosages of PTFE. Water contact angle and coefficient of friction at the microtexture level were measured to evaluate superhydrophobicity and skid resistance of the coated asphalt concrete. The optimum dosage and spay time that maximized hydrophobicity and skid resistance of flexible pavement while minimizing cost were estimated using a multi-objective Bayesian optimization (BO) method that replaced the more costly experimental procedure of pavement testing with a cheap-to-evaluate surrogate model constructed based on kriging. In this method, the surrogate model is iteratively updated with new experimental data measured at proper input settings. The result of proposed optimization method showed that the super water repellency and coefficient of friction were not uniformly increased for all the specimens by increasing spray time and dosage. In addition, use of the proposed multi-objective BO method resulted in hydrophobicity and skid resistance being maximally augmented by approximately 23% PTFE dosage at a spray time of 5.5 s. Highlights Effects of spray time and dosage on the hydrophobicity and friction of asphalt were investigated. A layer-by-layer method was utilized for spray depositing polytetrafluoroethylene on an asphalt concrete. The optimum dosage and spay time were estimated by using a multi-objective Bayesian optimization method. An acquisition function that can tackle problems involving multiple objective functions was proposed. The optimum hydrophobicity and skid resistance were achieved with 23% PTFE dosage and at a spray time of 5.5 s.

Antifouling Super Water Absorbent Supramolecular Polymer Hydrogel as an Artificial Vitreous Body.

Recently, there has been a high expectation that high water absorbent hydrogels can be developed as an artificial vitreous body. However, the drawbacks associated with in vivo instability, biofouling, uncontrollable in situ reaction time, and injection‐induced precrosslinked fragmentation preclude their genuine use as vitreous substitutes. Here, a supramolecular binary copolymer hydrogel termed as PNAGA‐PCBAA by copolymerization of N‐acryloyl glycinamide (NAGA) and carboxybetaine acrylamide (CBAA) is prepared. This PNAGA‐PCBAA hydrogel physically crosslinked by dual amide hydrogen bonds of NAGA exhibits an ultralow solid content (1.6, 98.4 wt% water content), and shear‐thinning behavior, body temperature extrudability/self‐healability, rapid network recoverability, and very close key parameters (modulus, antifouling/antifibrosis, light transmittance, refractive index, ultrastability) to human vitreous body. It is demonstrated that the hydrogel can be readily injected by a 22G needle into the rabbits' eyes where the gelling network is rapidly recovered. After 16 weeks postoperation, the hydrogel acts as a very stable vitreous substitute without affecting the structure of soft tissues in eye, or eliciting adverse effects. This supramolecular binary copolymer hydrogel finds a broad application in ophthalmic fields as not only a self‐recoverable permanent vitreous substitute, but also transient intraocular filling for prevention of inner tissues in postsurgical eyes.

Study of Super Hydrophilic Surface Modification and Visualization of Evaporation

The aim of this study is to use nanoscale bilayers assembly tacking surface modification on stainless steel plate, to make the surface modification of the Super hydrophilic surface, and then as the visualization of droplet evaporation and evaporation efficiency of the study, the paper made nano-film in the form of overlapping surface modification, change its hydrophilicity, and then take water as the working fluid for evaporation behavior visualization observation. The change parameters include droplet size (1μl-5μl), droplet extension area and liquid film thickness, with the change of evaporation time, further analysis of evaporation enhancement efficiency. The results showed that the best modified 18-layer Contact angle was 4 ⁰ surface of the super hydrophilic water. The results of evaporation test showed that the best evaporation efficiency of plate was about 550% the liquid droplet was more than 3μl, the effect was stable at 550%, less than 3μl also had more than 450% promotion.

Thermal-hydraulic analysis of a novel design super critical water reactor with Al2O3 nanofluid as a coolant

In this study the thermal-hydraulic analysis of the SCWR reactor with a new geometric design is discussed. In the new design, coolant and moderator circuits are separated and nanofluid has been used as coolant of the reactor core. In the performed sub-channel analysis, the conservation equations of mass, momentum and energy are solved numerically. Since in the new geometry the coolant and moderator circuits are separated, compared to previous plans, using the nanofluids with higher mass fraction of nanoparticles is applicable. In this article, the thermal-hydraulic analysis is performed for various mass fractions of Al2O3 nanoparticle and moderator velocities. Calculations show that the core outlet temperature grows up with increasing nanoparticle mass fraction. As it was expected, by increasing the nanoparticle mass fraction the core pressure drop will be raised, but in the proposed design this pressure drop is much lower.

Super water absorbing polymeric gel from chitosan, citric acid and urea: Synthesis and mechanism of water absorption

A new superabsorbent with maximum water absorption capacity of ∼1250 g/g is prepared by hydrothermal synthesis from sustainable and biodegradable resources such as chitosan, citric acid and urea (denoted as ‘CHCAUR’). CHCAUR is characterized extensively by various analytical techniques such as PXRD, SSNMR, FTIR, and TGA. Pure and saline water absorption study showed that CHCAUR could be a better adsorbent compared to the super absorbent polymer (SAP) used in commercial diaper material. The mechanism of water absorption is shown to arise out of a combination of electrostatic attraction of water to the ionic crosslinks and the presence of macropores as well as undulated surface due to the formation of nanofibrous bundles. When applied to soil CHCAUR was found to decrease water evaporation rate significantly.

Comparison of ANN and RKS approaches to model SCC strength

Self compacting concrete (SCC) is a high performance concrete that has high flowability and can be used in heavily reinforced concrete members with minimal compaction segregation and bleeding. The mix proportioning of SCC is highly complex and large number of trials are required to get the mix with the desired properties resulting in the wastage of materials and time. The research on SCC has been highly empirical and no theoretical relationships have been developed between the mixture proportioning and engineering properties of SCC. In this work effectiveness of artificial neural network (ANN) and random kitchen sink algorithm(RKS) with regularized least square algorithm(RLS) in predicting the split tensile strength of the SCC is analysed. Random kitchen sink algorithm is used for mapping data to higher dimension and classification of this data is done using Regularized least square algorithm. The training and testing data for the algorithm was obtained experimentally using standard test procedures and materials available. Total of 40 trials were done which were used as the training and testing data. Trials were performed by varying the amount of fine aggregate, coarse aggregate, dosage and type of super plasticizer and water. Prediction accuracy of the ANN and RKS model is checked by comparing the RMSE value of both ANN and RKS. Analysis shows that eventhough the RKS model is good for large data set, its prediction accuracy is as good as conventional prediction method like ANN so the split tensile strength model developed by RKS can be used in industries for the proportioning of SCC with tailor made property.

Actividad esporicida de la solución electrolizada con ph neutro en hongos de importancia postcosecha

El agua electrolizada con pH neutro (7.0) es un novedoso agente antimicrobiano, que tiene efecto en una gran variedad de microorganismos, seguro para los seres humanos y el medio ambiente. Se determinó la eficacia del agua electrolizada de súper oxidación con pH neutro (SES) en la reducción de la germinación de esporas y desarrollo del tubo germinativo en hongos de importancia postcosecha. Una suspensión de 8X107esporas·mL-1 de los hongos Botrytis cinerea aislado de zarzamora, Colletotrichum gloeosporioides aislado de mango, guayaba y lichi, Fusarium solani aislado de chile y estevia, Monilinia fructicola aislado de durazno, Penicillium digitatum aislado de limón mexicano y limón persa, Penicillium sp. aislado de papaya y Rhizopus stolonifer aislado de yaca y guanábana, estuvieron en contacto con la SES por 5 minutos a concentraciones de 3, 5, 6, 8, 18, 24, 27, 29, 36 y 43 ppm de cloro libre, y agua destilada estéril (testigo). Las esporas se sembraron en medio de cultivo papa dextrosa agar (Bioxon®); las evaluaciones se realizaron a las 24 y 48 horas posteriores a la siembra. La inhibición del 100 % en la germinación de esporas y longitud del tubo germinativo de Botrytis se observó en el rango de concentración de 18-43 ppm, Colletotrichum (6-43 ppm), Fusarium (6-43 ppm), Monilinia (8 y 24-43 ppm), Penicillium (18-43 ppm), Rhizopus aislado de guanábana (5-24 y 29-43 ppm) y Rhizopus de yaca (18-43 ppm). Los resultados sugieren que la SES podría ser utilizada como alternativa de control de hongos postcosecha.
 

Preparation and characterization of SLS-CNT/PES ultrafiltration membrane with antifouling and antibacterial properties

Carbon nanotubes (CNTs) were functionalized by a simple non-covalent modification with sodium lignosulfonate (SLS), and the hybrid polyethersulfone (PES) ultrafiltration membranes were prepared by phase inversion method with different ratios of functionalized carbon nanotubes (f-CNTs). SEM analysis indicated that obvious finger-like pores appeared in f-CNT/PES hybrid membranes. The f-CNTs were uniformly dispersed on the membrane surface, causing super hydrophilicity and high water flux of the f-CNT/PES hybrid membranes. Filtration and protein adsorption tests indicated that the antifouling performances were dramatically increased, the amount of protein pollutants adsorbed by the hybrid membranes was significantly lower than the nascent membranes, and most of the water flux can be recovered after three cycles of the BSA solution fouling process. The antibacterial tests confirmed that no prepared membranes showed excellent antibacterial properties to Escherichia coli (E. coli). However, the hybrid membrane showed good antibacterial properties treated with a low-voltage electric field (direct current (DC), about 1.5Vcm−1), and the antibacterial rate (AR) closed to 100% after testing for 3h.

Micro-nanostructure-based super-hydrophobic surface on cotton fabric

Inspired by the super water repellency owing to the hierarchal micro- and nano-structural features observed in nature, we constructed similar hierarchal surfaces in both micro and nano sizes on cotton fabrics via a two-step sol-gel method. Silica sol-gel particles were prepared by the modified Stöber method of hydrolysis and condensation of tetraethylorthosilicate as a precursor. Through adjusting the volume of NH3·H2O, particles of various sizes were obtained. Using the dip-pad-dry-cure method, the cotton fabrics were finished with the silica sol gels of micro- and nano-sizes, and followed by low surface energy modification of hexadecyltrimethoxysilane. The results showed that the thus structured surface made the cotton fabrics much more hydrophobic with a water contact angle near 162O, close to that of the lotus leaf.

Super compact equation for water waves

Mathematicians and physicists have long been interested in the subject of water waves. The problems formulated in this subject can be considered fundamental, but many questions remain unanswered. For instance, a satisfactory analytic theory of such a common and important phenomenon as wave breaking has yet to be developed. Our knowledge of the formation of rogue waves is also fairly poor despite the many efforts devoted to this subject. One of the most important tasks of the theory of water waves is the construction of simplified mathematical models that are applicable to the description of these complex events under the assumption of weak nonlinearity. The Zakharov equation, as well as the nonlinear Schrödinger equation (NLSE) and the Dysthe equation (which are actually its simplifications), are among them. In this article, we derive a new modification of the Zakharov equation based on the assumption of unidirectionality (the assumption that all waves propagate in the same direction). To derive the new equation, we use the Hamiltonian form of the Euler equation for an ideal fluid and perform a very specific canonical transformation. This transformation is possible due to the ‘miraculous’ cancellation of the non-trivial four-wave resonant interaction in the one-dimensional wave field. The obtained equation is remarkably simple. We call the equation the ‘super compact water wave equation’. This equation includes a nonlinear wave term (à la NLSE) together with an advection term that can describe the initial stage of wave breaking. The NLSE and the Dysthe equations (DystheProc. R. Soc. Lond.A, vol. 369, 1979, pp. 105–114) can be easily derived from the super compact equation. This equation is also suitable for analytical studies as well as for numerical simulation. Moreover, this equation also allows one to derive a spatial version of the water wave equation that describes experiments in flumes and canals.

A-35 超節水型大便器が排水立て管システムに及ぼす影響に関する実験的研究 : 第2報器具排水特性と管内圧力の検討

A-35 超節水型大便器が排水立て管システムに及ぼす影響に関する実験的研究 : 第2報器具排水特性と管内圧力の検討

A-34 超節水型大便器が排水立て管システムに及ぼす影響に関する実験的研究 : 第1報器具排水特性と搬送性能の検討

A-34 超節水型大便器が排水立て管システムに及ぼす影響に関する実験的研究 : 第1報器具排水特性と搬送性能の検討

Effect of Mg/Al ratios on hydration mechanism of tabular alumina carbon composites reinforced by Al4C3 in situ reaction

Hydration mechanism of tabular alumina carbon composites reinforced by Al4C3 in situ reaction with Mg and Al was researched in water steam using super automatic thermostatic water bath from 25 °C to 85 °C. It is shown that hydration mechanism of the composites is chemical reaction control at 44.3 °C-84 °C in H2O(g). The hydration was controlled by diffusion from 24.7 °C to 33 °C. The ratio of added Mg/Al influences the HMOR of the composites.The mechanism of HMOR of the composites with different ratios of Mg/Al can be discovered by means of SEM analysis. The active Mg/Al powder and flake graphite inside give the composites outstanding hot strength resulting from the interlocking structure of Al4C3 crystals at high temperature. Besides, the matrix changes into the Al4C3 with high refractoriness. The method of preventing the hydration of tabular alumina carbon composites reinforced by Al4C3 in situ reaction was immersed in the wax at suitable temperature or storing them below 33 °C in a dry place or storing them with paraffin-coating.

Oxidation Behavior of UHP Fe-Based Model Alloy and SUS310S Steel in Superheated Steam and Supercritical Water Conditions

The quest for improvements in cycle efficiency of energy production plants leads to progressively higher operating temperatures and pressures in steam boiler. For this reason, the oxidation resistance of structural materials is the key issue, and hence, the consequences of increased growth rate of the oxides pose serious concern, such as oxide exfoliation. The oxidation behavior of ultra-high-purity (UHP) Fe–23Cr–23Ni–2Mo–0.6Nb wt% model alloy and SUS310S in steam and super critical water at atmospheric pressure and 25 MPa, respectively, and at 973 K (700 °C) is investigated. To elucidate the oxidation behavior, weigh gain measurement and characterization of the resulting oxide were performed. The critical chromium content to form and maintain protective oxide increased with increasing the pressure, 23 wt% in steam and 26 wt% in SCW conditions. Grain refinement was efficient for enhancing the oxidation resistance of SUS310S.

フラクタル構造による超撥水/撥油表面(インダストリアルマテリアルズ)

フラクタル構造による超撥水/撥油表面(インダストリアルマテリアルズ)

7-15p トマト残渣の超臨界水ガス化システムによる処理の経済性研究(新エネルギー等,研究発表(ポスター発表))

7-15p トマト残渣の超臨界水ガス化システムによる処理の経済性研究(新エネルギー等,研究発表(ポスター発表))

The low adhesion problem due to leaf contamination in the wheel/rail contact: Bonding and low adhesion mechanisms

Autumn leaves often cause low adhesion problems for train operations, leading to station overruns and signals passed at danger (SPADS). The aim of this paper was to review operational data and research methods to assess the current understanding of the problem and formulate hypotheses for the causes. Incident analysis showed the relatively high possibility of incidents between the hours of 05:00–10:00 and 20:00–24:00, suggesting the dew effect was important. This result corresponds to the knowledge that wet leaves in the contact area produce very low friction coefficients, below 0.1. Current mitigation methods, such as sanding, seem inadequate to remove the leaf films completely. To explain the bonding mechanism between the leaf film and the rail, a laboratory-based model and a field-based model were developed based on previous studies. Moreover, key parameters for a strong bond formation were identified, which are iron oxide, temperature, pressure and leaf material. The research gaps were identified by a paper grading method, and several hypotheses for bonding mechanisms and low adhesion mechanisms were proposed, such as sub- or super critical water and pectin gel.

Super water absorbency OMMT/PAA hydrogel materials with excellent mechanical properties

Montmorillonite/poly(acrylic acid) composite hydrogels, fabricated through UV irradiation polymerization, have a super water absorbency of 2786 g g−1and excellent mechanical properties.