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Soils are a host to several micro‐organisms which are responsible for various biogeochemical processes prevailing in the geoenvironment. Such processes have been utilized to alter engineering properties of the coarse‐grained soils viz., sands, such as strength, liquefaction potential and permeability. One of such processes, which has been explored by several researchers, is Biogenic Calcite Precipitation (BCP) in the coarse‐grained soils. Though the impact of biogenic calcite (BC) on engineering behaviour of sands has been dealt with in great detail, the mechanism of calcite 'growth' on their surface, which primarily depends on biosorption (i.e. attachment of bacterial cells), has not been investigated and/or discussed in detail. It should be noted that biosorption would strongly depend upon the overall surface characteristics of the sand grains, apart from their chemico‐mineralogical characteristics. Unlike fine‐grained soils, where the bacteria‐soil interaction is being investigated extensively by researchers, the above‐referred studies on sands have been pretermitted, largely. With this in view, an attempt has been made to investigate the mechanisms associated with the interaction of bacterial cells with sand grains and BC substrates, which is a precursor for the biogeochemical processes such as BCP, bioremediation and biological degradation of soils. Highlighting the role of key factors in bacterial cell‐sand interactions, a conceptual model has been proposed for the growth of biogenic calcite around a sand grain. Such a fundamental study, conducted by employing Atomic Force Microscopy and Extended Derjaguin‐Landau‐Verwey‐Overbeek (ExDLVO) theory, provides an insight into the biosorption on sands and BC. [ABSTRACT FROM AUTHOR]

This paper investigates the problems of the observer-based fault estimation (FE) and fault-tolerant control (FTC) for nonlinear systems subjected to external disturbances by the T–S fuzzy model method with local nonlinear models. Firstly, an FE strategy is proposed based on the unknown input observer technology, where the local nonlinear terms can be decoupled from the FE error system for relaxing the design of observer. Then, by using the FE information, a fuzzy fault-tolerant controller is designed to guarantee the stability of the system. Additionally, in the design schemes of the FE observer and the fault-tolerant controller, the L ∞ method is used to deal with the problems of FE and FTC for the system with persistent disturbance such that the robustness of the system against the persistent external disturbance can be increased. Compared with the traditional H ∞ method which is only applicable for dealing with the energy bounded signals, the L ∞ FTC strategy proposed in this paper can deal with the persistent disturbance such that the shortcomings of the traditional H ∞ approach are overcome. Finally, the effectiveness of the proposed method is verified by simulation results. [ABSTRACT FROM AUTHOR]

An effective and efficient photovoltaic performance is significantly affected by the interface between different constituents of dye sensitized solar cells (DSSC). A novel dual post treatment of TiCl4 and urea solutions on different layers of TiO2 electrode is addressed and the TiO2 particle morphology, dye‐adsorption amount on the TiO2 electrode and the photovoltaic performance of the DSSC based on those electrodes are characterised in this work. TiCl4 treatment can form more binding site on TiO2 particles and urea treatment structures a thin layer of g‐C3N4 on the surface of TiO2 particles. This strategy can not only effectively increase the dye‐adsorption for light‐harvesting, but also facilitate the electron transfer through inhibiting the charge recombination between TiO2 and electrolyte, and moreover, it provides excess electrons for the photoanodes. The DSSC fabricated from TiO2 electrode processed with urea treatment on the sixth layer exhibited the highest power conversion efficiency of 8.94% with a short current density Jsc of 24.09 mA cm–2, an open circuit voltage Voc of 583 mV and a fill factor of 63.8. [ABSTRACT FROM AUTHOR]

Due to more extreme weather events and accelerating sea-level rise, coastal sand dunes are subjected to more frequent storm wave inundation and surge impacts, which contribute to widespread coastal erosion problems. In this study, two novel bio-mediated methods, microbial-induced carbonate precipitation (MICP) and enzymatic-induced carbonate precipitation (EICP), were investigated and compared for their effectiveness in mitigating sand dune erosion under wave attack. Small-scale laboratory model tests were performed on MICP-treated, EICP-treated, and untreated sand dunes at dune slope angles and two wave intensities for up to 2 h. The cross-shore profile was captured continuously during the course of the erosion test. The erosion volume above the still water level (SWL) and landward retreat distance at the SWL were calculated based on the captured bed profiles. The results show that both EICP and MICP could substantially reduce sand dune erosion at mild-to-moderate wave and dune slope conditions. However, the effectiveness of MICP treatment deteriorated at steeper dune slopes with longer period of wave attack. Under the most adverse condition (i.e., steepest dune slope, biggest wave, and longest period of wave attack), neither EICP nor MICP could effectively mitigate erosion. Fundamentally, the variable effectiveness of MICP and EICP treatment for sand dune erosion control was attributed to the spatial distribution pattern of formed calcite precipitation, which was determined by the way how EICP and MICP were applied. The calcite precipitation was relatively uniform in EICP-treated sand dunes. In MICP-treated ones, however, substantial calcite precipitation concentrated in the shallow surface layer as confirmed by the surface penetration test and SEM observation. [ABSTRACT FROM AUTHOR]

Organic matter–disseminated sand (OMDS) is a widely distributed problematic soil in coastal areas of Hainan province, China. Its existence makes the installation of piles difficult and has the risk of insufficient bearing capacity. OMDS is different from other organic soils such as peat in terms of formation, mineral component, organic content, and forms of organic matters. In this study, 20% (w/w) cement together with 7.5% (w/w) lime at a water–cement ratio of 0.45 was mixed with OMDS to improve its mechanical performances. A series of unconsolidated undrained static triaxial test was conducted on the stabilized OMDS to investigate the failure mode, stress–strain relationship, maximum and residue deviator stress, axial strain at failure, and elastic modulus under various confining pressures (0, 200, 300, 400 kPa) and curing time (7d, 14d, 28d). The test results showed that higher confining pressure and longer curing time in general led to higher maximum and residue deviator stress, larger axial strain at failure, and larger secant elastic modulus of cement-stabilized OMDS. The maximum and residue deviator stress of cement-stabilized OMDS increased with curing time and ranged from 500 to 2180 kPa and from 250 to 1800 kPa, respectively. Under elevated confining pressure, maximum deviator stress increased substantially, irrespective of curing time. Secant elastic modulus (E50) increased with confining pressure at these three curing time, from 29 to 42 MPa. Due to the existence of organic matters, the strength of cement-stabilized OMDS was lower than cement-stabilized non-organic sand, regardless of confining pressure and curing time. This study provided new insight into the shear strength behavior of cement-stabilized OMDS under different confining conditions. This will facilitate the design and construction of foundations in this type of soil. [ABSTRACT FROM AUTHOR]

publisher‐imprint‐name Springer volume‐issue‐count 1 issue‐article‐count 0 issue‐toc‐levels 0 issue‐pricelist‐year 2020 issue‐copyright‐holder The Author(s) issue‐copyright‐year 2020 article‐contains‐esm Yes article‐numbering‐style Unnumbered article‐registration‐date‐year 2020 article‐registration‐date‐month 1 article‐registration‐date‐day 6 article‐toc‐levels 0 toc‐levels 0 volume‐type Regular journal‐product ArchiveJournal numbering‐style Unnumbered article‐grants‐type OpenChoice metadata‐grant OpenAccess abstract‐grant OpenAccess bodypdf‐grant OpenAccess bodyhtml‐grant OpenAccess bibliography‐grant OpenAccess esm‐grant OpenAccess online‐first false pdf‐file‐reference BodyRef/PDF/40169_2020_Article_257.pdf pdf‐type Typeset target‐type OnlinePDF issue‐type Regular article‐type OriginalPaper journal‐subject‐primary Medicine & Public Health journal‐subject‐secondary Medicine/Public Health, general journal‐subject‐collection Medicine open‐access true --> Background: The present study sought to identify a panel of DNA markers for noninvasive diagnosis using cell‐free DNA (cfDNA) from urine supernatant or cellular DNA from urine sediments of hematuria patients. A panel of 48 bladder cancer‐specific genes was selected. A next‐generation sequencing‐based assay with a cfDNA barcode‐enabled single‐molecule test was employed. Mutation profiles of blood, urine, and tumor sample from 16 bladder cancer patients were compared. Next, urinary cellular DNA and cfDNA were prospectively collected from 125 patients (92 bladder cancer cases and 33 controls) and analyzed using the 48‐gene panel. The individual gene markers and combinations of markers were validated according to the pathology results. The mean areas under the receiver operating characteristic (ROC) curves (AUCs) obtained with the various modeling approaches were calculated and compared. Results: This pilot study of 16 bladder cancer patients demonstrated that gene mutations in urine supernatant and sediments had better concordance with cancer tissue as compared with plasma. Logistic analyses suggested two powerful combinations of genes for genetic diagnostic modeling: five genes for urine supernatant (TERT, FGFR3, TP53, PIK3CA, and KRAS) and seven genes for urine sediments (TERT, FGFR3, TP53, HRAS, PIK3CA, KRAS, and ERBB2). The accuracy of the five‐gene panel and the seven‐gene panel in the validation cohort yielded AUCs of 0.94 [95% confidence interval (CI) 0.91–0.97] and 0.91 (95% CI 0.86–0.96), respectively. With the addition of age and gender, the diagnostic power of the urine supernatant five‐gene model and the urine sediment seven‐gene model improved as the revised AUCs were 0.9656 (95% CI 0.9368–0.9944) and 0.9587 (95% CI 0.9291–0.9883). Conclusions: cfDNA from urine bears great diagnostic potential. A five‐gene panel for urine supernatant and a seven‐gene panel for urine sediments are promising options for identifying bladder cancer in hematuria patients. [ABSTRACT FROM AUTHOR]

Durability of cement-based materials for marine/coastal structures is an increasingly challenging problem. Sulfate ions in seawater can react with aluminate in cement to form erosion products, causing cracks and spalling. When cement is used to stabilize loose erodible sand in coastal areas, the resistance to sulfate attack is questionable. In this study, four cements with different aluminate contents were used to stabilize sand. Cement stabilized sands were immersed in 5% Na2SO4 solution for 300-days to simulate long-term sulfate attack process. The deterioration of engineering performance was evaluated based on expansion ratio, mass change, uniaxial compressive strength, and ultrasonic velocity. The deterioration mechanisms were analyzed through mineralogical and microstructural observations including X-ray diffraction, EDS, scanning electronic microscopy, and nuclear magnetic resonance. The results showed that the development of macro-scale mechanical performances could be divided into two stages (initial stage and erosion stage) when subjected to 300-days immersion in 5% Na2SO4 solution. Sand stabilized by low-aluminate-content cement displayed better engineering performance especially at the erosion stage. Mechanistically, more ettringite was formed in high-aluminate-content cement stabilized sand, leading to swelling and cracking. The formation of ettringite and gypsum were accompanied with the consumption of portlandite, leading to further strength loss. [ABSTRACT FROM AUTHOR]

In this paper, the design problem of intelligent ship autopilot with unmeasured yaw rate and input saturation is investigated based on adaptive fuzzy control. First, an adaptive fuzzy output feedback controller is proposed, then, to improve the convergence speed of the tracking error in the sense of finite time, a finite-time adaptive fuzzy output feedback controller is also designed to improve the control performance. By employing fuzzy logic system (FLS) to estimate the unknown nonlinear function, an adaptive fuzzy state observer is designed to estimate the unmeasured state. An adaptation auxiliary signal for input saturation is also established to compensate the mismatch between the controller signal and the actuator signal. Combining state observer model with backstepping method, two different adaptive fuzzy output-feedback controllers with composite parameter adaptive laws are constructed, respectively. Based on Lyapunov theory, it is proved that all signals in the closed-loop systems are bounded. Finally, the simulation results are conducted to demonstrate the effectiveness of the proposed schemes. [ABSTRACT FROM AUTHOR]

Rare earth organic complex materials have attracted tremendous attention for their intrinsic properties and promising practical applications. It is still a great challenge to realize the rare earth organic complex materials with excellent functional properties and diversified structural states. Here, the amino acid rare earth surfactant complexes of lanthanum octanoyl-alaninate (La(oct-ala) 3), lanthanum octanyl-serinate (La(ser-oct) 3) and lanthanum octanoyl-phenylalaninate (La(oct-phe) 3) were synthesized by the reaction of C 11 H 21 NO 3 , C 11 H 21 NO 4 , C 17 H 26 NO 3 with LaCl 3 , respectively. As-synthesized complexes of La(oct-ala) 3 and La(oct-phe) 3 have high solubility in pure solvent, while the solubility of La(ser-oct) 3 is very low in pure solvent. When the concentration of the complex solution is lower than the critical micelle concentration, the dissociation phenomenon of the complex is occurred in the solution. When the concentration of the complex solution is greater than the critical micelle concentration, the dissociated ligand ions and metal ions will associate, which can form micelle aggregates. In addition, the aggregates of the complex gradually shrink to form aggregates of different sizes and sizes as the solvent continues to volatilize. By further heating and cooling, the glassy, crystalline, liquid crystal and other complexes can be obtained. The rare earth organic low molecular complexes formed by the combination of these rare earth ions and amino acid ligands can not only obtain the complexes with high rare earth content, but also have the excellent properties of convenient synthesis, high yield, easy processing, good solubility, low toxicity and high stability, etc., which can play the special physical and chemical functional characteristics of the diversified structure state of rare earth organic molecular materials. Therefore, in present work, the lanthanum complexes as a functional molecular materials have potential applications in many fields. [ABSTRACT FROM AUTHOR]

Reactive magnesia (MgO)-activated ground granulated blast furnace slag (GGBS) is a newly developed binder for soil stabilization/solidification. It can be used as an alternative of conventional hydraulic binders for the stabilization/solidification of heavy metal-contaminated soils. Acid rain exposure has been found to weaken the heavy metal immobilization in solidified/stabilized soils in the long term. However, very limited studies have been conducted to investigate the effect of acid rain on the physical and strength properties of GGBS–MgO-stabilized heavy metal-contaminated soils. In this study, GGBS–MgO-stabilized lead (Pb)-contaminated soils are subjected to the semi-dynamic leaching test using the simulated acid rain (SAR) as leachant, which has pH values of 2.0, 3.0, 4.0, and 5.0. Deionized water (pH 7.0) is also used for comparison. Dry density, soil pH, needle penetration depth, and unconfined compressive strength (qu) of the solidified/stabilized soils are measured after the leaching test. The results show that exposure to SAR yields reduction in qu and soil pH, whereas the needle penetration depth increases and dry density changes only marginally. The qu of the solidified/stabilized soils increases noticeably with increased GGBS–MgO content. It is also found that the stabilized Pb-contaminated soil exhibits lower qu than its clean soil counterpart. Furthermore, a quantitative relationship is proposed to correlate the normalized needle penetration resistance with the normalized qu. Finally, a multiple linear regression is performed to statistically reveal the dependence of soil strength on three independent variables, which are SAR pH, Pb concentration and binder content. [ABSTRACT FROM AUTHOR]