Search

• Critical review on the durability study of high ductility cementitious composites in sulfate environments. • Sulfate erosion on the mechanical properties, fiber–matrix interface, pore structure and microstructure evolution of HDCC. • Existing problems and further directions for durability research of HDCC. Engineering buildings in severe environments (such as marine or salt lakes) are extremely vulnerable to sulfate attacks resulting in swelling and cracking, shortening the service life of the structure. The brittle fracture of ordinary concrete is a tremendous safety hazard for production and life. Thus, the enhancement of ductility and toughness of cement-based materials has been the endeavor of researchers in recent decades. High ductility cementitious composites (HDCC) with multiple cracking and strain hardening characteristics efficiently ameliorate the defects of poor ductility, low toughness, and weak crack control ability of concrete, which largely satisfies the engineering demands. However, sulfate attack affects the performance of HDCC and corrosion products bring diverse degrees of damage to the strength, ductility, fiber–matrix interface, etc. How it will affect the pivotal properties of HDCC is currently unclear. Therefore, based on the latest studies of HDCC, this paper reviews the effects of sulfate attack on the macromechanical properties, fiber–matrix interface properties, pore structure development and microstructure evolution of HDCC. The potential problems and research directions are also proposed from erosion damage mechanism, characterization instruments of destruction degree, micromechanical design theory and service life prediction and critical performance enhancement. [ABSTRACT FROM AUTHOR]

Liquid pool fires may represent the initiating fire hazard in many risk assessments associated with industrial plants. As real industrial fire scenarios generally include numerous obstructions, a pool fire burning behind an obstruction is a challenging task in the industrial risk assessment. A systematic investigation was conducted on the flame characteristics of a pool fire sheltered by a plate obstacle with different heights and geometrical dimensions, where the flame morphology, flame height, flame width and flame radiation flux were recorded and studied. The results show that the flame morphology for a pool fire sheltered by a plate obstacle can be divided in three types. For the radiation heat flux evolution over the entire burning process, it was found that the plate obstacle above the fuel pool would lead to a larger peak value of the radiation heat flux. Using a physical and dimensionless method, prediction models for flame characteristics including flame width, flame height and maximum value of radiation heat flux were proposed. [ABSTRACT FROM AUTHOR]

This present experiment was performed to investigate the effects of dietary supplementation of chitosan (CS) on immune function in growing Huoyan geese. A total of 320 28-day-old healthy growing Huoyan geese (sex balance) with similar body weight were randomly allotted into control, CS100, CS200, and CS400 groups. Each group includes 4 replicates with 20 geese per replicate, and the feeding trial lasted for 4 wk. The 4 diets contained 0, 100, 200, and 400 mg CS per kg feed, respectively. The results showed that compared with the control group, the relative weight of thymus, serum concentrations of IGF-I, INS, GH, T3, T4, IgM, IgG, IgA, complement C3, and IL-2 in CS200 group were significantly higher at both 42 and 56 D of age, respectively (P < 0.05). In addition, relative weight of bursa of fabricius (BF), spleen, serum complement C4, and TNF-a concentrations in CS200 group were higher at 56 D of age (P < 0.05), no differences were observed at 42 D of age (P > 0.05). These results indicated that addition of 200 mg/kg CS enhanced immune organs weight, serum concentrations of immunoglobulins, complements, hormone, as well as cytokines, and improved immune function of growing Huoyan geese. [ABSTRACT FROM AUTHOR]

Abstract: The characteristics and performance of two tunnel lighting systems are investigated in this paper. Tunnel No. 1 is installed with induction electrodeless fluorescent lamps and tunnel No. 2 is installed with high pressure sodium (HPS) lamps. The luminance levels and illuminating uniformity with two systems were measured and analyzed. The spectrum and energy cost have also been studied. Additionally, the responses of drivers were investigated. By the comparison of these two tunnel lighting systems, it was found that the tunnel lighting system with induction lamps shows advantages in high brightness perception to drivers, good color rendering, higher uniformity, better safety perception to drivers and low energy cost over the tunnel lighting system with HPS lamps. [Copyright &y& Elsevier]

The thermal, water and electrochemical stability of Cu-based metal organic frameworks (Cu-MOFs) confined in macroporous carbon (MPC) hybrids has been investigated. Thermogravimetric analyses, X-Ray diffraction, scanning electron microscopy, and cyclic voltammetry were employed to confirm the stability of pure Cu-MOFs, MPC, and Cu-MOFs-MPC. As compared to pure Cu-MOFs, the porous composite materials of MPC and Cu-MOFs interact and seem to form new materials having homogenous structure and chemistry, which show structural stability in aqueous media and electrochemical stability in phosphate buffer solution (PBS pH 7.4). The detection of ascorbic acid and hemoglobin is performed as an electrochemical probe, indicating Cu-MOFs-MPC holds great promise for the design of electrochemical sensors. [ABSTRACT FROM AUTHOR]

To what extent do early intuitions about ownership depend on cultural and socio-economic circumstances? We investigated the question by testing reasoning about third party ownership conflicts in various groups of three- and five-year-old children (N=176), growing up in seven highly contrasted social, economic, and cultural circumstances (urban rich, poor, very poor, rural poor, and traditional) spanning three continents. Each child was presented with a series of scripts involving two identical dolls fighting over an object of possession. The child had to decide who of the two dolls should own the object. Each script enacted various potential reasons for attributing ownership: creation, familiarity, first contact, equity, plus a control/neutral condition with no suggested reasons. Results show that across cultures, children are significantly more consistent and decisive in attributing ownership when one of the protagonists created the object. Development between three and five years is more or less pronounced depending on culture. The propensity to split the object in equal halves whenever possible was generally higher at certain locations (i.e., China) and quasi-inexistent in others (i.e., Vanuatu and street children of Recife). Overall, creation reasons appear to be more primordial and stable across cultures than familiarity, relative wealth or first contact. This trend does not correlate with the passing of false belief theory of mind. [ABSTRACT FROM AUTHOR]

Nitrogen and sulfur dual doped-carbon nanotubes-mesoporous carbon (D-CNTs-MPC) composite is prepared simultaneously and is used in alkaline media as an electrocatalyst for oxygen reduction reaction (ORR). D-CNTs-MPC is synthesized by casting method using nano-CaCO3 as a template, and binuclear cobalt phthalocyanine hexasulfonate as a carbon, nitrogen and sulfur precursor as well as the catalyst for growth of CNTs. D-CNTs-MPC possesses short CNTs adhering to loosely packed carbon with mesopores. Moreover, nitrogen and sulfur are doped into the carbon framework without addition of other heteroatom-containing precursor. The electrochemical behavior shows that D-CNTs-MPC is an active, methanol-tolerant and stable electrocatalyst for ORR. [ABSTRACT FROM AUTHOR]

By using eco-friendly polydopamine as carbon and nitrogen precursor and commercial hydrophilic nano-CaCO3as hard-template; a one step, cost-effective and green method to synthesize nitrogen-doped porous carbon (NPC) is presented. A series of NPC samples with different nitrogen contents have been reported. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectra (EDX), fourier transform infrared spectroscopy (IR), Raman spectroscopy, X-ray diffraction (XRD), nitrogen adsorption-desorption and X-ray photoelectron spectra (XPS) were employed for characterizations of NPC. The influence of BET surface area and different amounts of N-bonding configurations of NPC for the electrocatalysis towards nitrobenzene (NB) and hydrazine (N2H4) were investigated in detail. Results indicated that NPC with largest BET surface area and highest amounts of pyrrolic N and graphitic N showed improved electrocatalytic activity for NB and N2H4in neutral solution. [ABSTRACT FROM AUTHOR]