Watershed erosion risk assessment and management utilizing revised universal soil loss equation‐geographic information systems in the Mediterranean environments

The generation of an easily adaptable method for erosion risk assessment is important for management and conservation of the available resources in developing countries. The study aims to assess the risk of soil erosion by using an integrated, easy to apply, time‐ and money‐conserving revised universal soil loss equation‐geographic information systems (RUSLE‐GIS)‐based model in the Eastern part of the Mediterranean. Although the model showed a good efficiency in predicting the annual soil loss (R²=0.68), the limited runoff–erosion data warrant the need for long‐term data to test and calibrate the model. The model showed that 24% of the watershed area has an annual soil loss exceeding the soil loss tolerance (SLT) of the area (5 Mg/ha). When all the RUSLE factors were kept constant, except the C factor, the model showed the highest soil loss potential under olive groves (20–30 Mg/ha), and the lowest under wheat and barley (5 Mg/ha). The application of proper conservation practices to these areas is thus important, i.e. reducing the number of tillage and/or time of tillage practices.     

Empirical evaluation of ductility factors for the special steel moment‐resisting frames in view of soil condition

It is well known that the response modification factor (R) takes into account the ductility, over‐strength, redundancy and damping of structural systems. The ductility factor has played an important role in seismic design, as it is a key component of R. In this study, the ductility factors (R_μ,MDOF) of special steel moment‐resisting frames are calculated by multiplying the ductility factor of single degree of freedom (SDOF) systems (R_μ,SDOF) with the multi‐degree of freedom (MDOF) modification factors (R_M). The ductility factors (R_μ,SDOF) of SDOF systems are computed from non‐linear dynamic analysis undergoing different levels of displacement ductility demands and periods when subjected to a large number of recorded earthquake ground motions. To compute the R_μ,SDOF, a group of 1,860 ground motions recorded from 47 earthquakes were considered. R_M factors are proposed to account for the MDOF systems, based on previous studies. A total of 108 prototype steel frames were designed to investigate the ductility factors, considering design parameters such as the number of stories (4, 8 and 16), framing systems (perimeter frames and distributed frames), failure mechanisms (strong column‐weak beam and weak column‐strong beam), soil profiles (S_A, S_C and S_E in Uniform Building Code 1997) and seismic zone factors (Z = 0·075, 0·2, and 0·4 in UBC 1997). The effects of these design parameters on the R_μ,MDOF of special steel‐moment‐resisting frames were investigated. Copyright © 2009 John Wiley & Sons, Ltd.     

Quantification of seismic performance factors for self‐centering controlled rocking special concentrically braced frame

Modern self‐centering controlled rocking special concentrically braced frame (SC‐CR SCBF) is capable of reducing structural damage compared with conventional buildings following an earthquake. This investigation quantifies three seismic performance factors, including over‐strength factor (Ω₀), period‐based ductility (μ_T) and response modification coefficient (R), for low‐ and mid‐rise SC‐CR SCBFs. Nonlinear static analysis is conducted to derive Ω₀ and μ_T factors for 12 SC‐CR archetypes. Validity of trial R coefficient is also evaluated using a collapse‐based assessment procedure by comparing adjusted collapse margin ratios with the established acceptance criteria. Results indicate that the Ω₀ and μ_T factors are in the range of 1.39 to 2.29 and 12.25 to 29.0, respectively, and R of 8 is proposed for design of SC‐CR archetypes. A reliability study is also performed to examine the effects of modeling and ground motion parameters on the safety margin of designed SC‐CR archetypes with the proposed R value. Results indicate that the design of mid‐rise space archetypes in high‐seismicity regions with the R coefficient of 8 is more reliable than that of the low‐rise perimeter ones in low‐seismicity regions. Copyright © 2016 John Wiley & Sons, Ltd.     

Oxygen utilization and biochemical stabilization rate constants for a brewery effluent

Composite samples of brewery effluents were obtained from a brewery in Benin City, Nigeria. They were analysed for their biochemical oxygen demand (BOD) values at 20°C for definite periods in days. From the values obtained, oxygen utilization and biochemical stabilization rate constants, k and K, respectively, were determined. The mean values obtained for them were 0.37 day^‐1 and 0.16 day^‐1 respectively. The ultimate BOD (L_o) value for the brewery effluent was 757.1 mg/l, and the ratio of the 5‐day BOD (BOD₅) to the Ultimate BOD (L_o) (i.e., BOD₅/L_o) was found to be 0.85.     

A quantitative structure‐property relationship (QSPR) for estimating solid material‐air partition coefficients of organic compounds

The material‐air partition coefficient (K_ma) is a key parameter to estimate the release of chemicals incorporated in solid materials and resulting human exposures. Existing correlations to estimate K_ma are applicable for a limited number of chemical‐material combinations without considering the effect of temperature. The present study develops a quantitative structure‐property relationship (QSPR) to predict K_ma for a large number of chemical‐material combinations. We compiled a dataset of 991 measured K_ma for 179 chemicals in 22 consolidated material types. A multiple linear regression model predicts K_ma as a function of chemical's K_oa, enthalpy of vaporization (?H_v), temperature, and material type. The model shows good fitting of the experimental dataset with adjusted R² of 0.93 and has been verified by internal and external validations to be robust, stable and has good predicting ability ( > 0.78). A generic QSPR is also developed to predict K_ma from chemical properties and temperature only (adjusted R² = 0.84), without the need to assign a specific material type. These QSPRs provide correlation methods to estimate K_ma for a wide range of organic chemicals and materials, which will facilitate high‐throughput estimates of human exposures for chemicals in solid materials, particularly building materials and furniture.     

Effective disinfection of airborne microbial contamination in hospital wards using a zero‐valent nano‐silver/TiO2‐chitosan composite

A novel antimicrobial composite of zero‐valent silver nanoparticles (AgNPs), titania (TiO₂), and chitosan (CS) was prepared via photochemical deposition of AgNPs on a CS‐TiO₂ matrix (AgNPs@CS‐TiO₂). Electron microscopy showed that the AgNPs were well dispersed on the CS‐TiO₂, with diameters of 6.69‐8.84 nm. X‐ray photoelectron spectra indicated that most of the AgNPs were reduced to metallic Ag. Fourier‐transform infrared spectroscopy indicated that some AgNPs formed a chelate with CS through coordination of Ag⁺ with the CS amide II groups. The zones of inhibition of AgNPs@CS‐TiO₂ for bacteria (Escherichia coli and Staphylococcus epidermidis) and fungi (Aspergillus niger and Penicillium spinulosum) were 6.72‐11.08 and 5.45‐5.77 mm, respectively, and the minimum (critical) concentrations of AgNPs required to inhibit the growth of bacteria and fungi were 7.57 and 16.51 µg‐Ag/mm², respectively. The removal efficiency of a AgNPs@TiO₂‐CS bed filter for bioaerosols (η) increased with the packing depth, and the optimal filter quality (qF) occurred for packing depths of 2‐4 cm (qF = 0.0285‐0.103 Pa^?1; η = 57.6%‐98.2%). When AgNPs@TiO₂‐CS bed filters were installed in the ventilation systems of hospital wards, up to 88% of bacteria and 97% of fungi were removed within 30 minutes. Consequently, AgNPs@TiO₂‐CS has promising potentials in bioaerosol purification.     

Reliable fragility functions for seismic collapse assessment of reinforced concrete special moment resisting frame structures under near‐fault ground motions

A collapse fragility function shows how the probability of collapse of a structure increases with increasing ground motion intensity measure (IM). To have a more reliable fragility function, an IM should be applied that is efficient and sufficient with respect to ground motion parameters such as magnitude (M) and source‐to‐site distance (R). Typically, pulse‐like near‐fault ground motions are known by the presence of a velocity pulse, and the period of this pulse (T_p) affects the structural response. The present study investigates the application of different scalar and vector‐valued IMs to obtain reliable seismic collapse fragility functions for reinforced concrete special moment resisting frames (RC SMRFs) under near‐fault ground motions. The efficiency and sufficiency of the IMs as the desirable features of an optimal IM are investigated, and it is shown that seismic collapse assessments by using most of the IMs are biased with respect to T_p. The results show that (Sa(T₁), Sa(T₁)/DSI) has high efficiency and sufficiency with respect to M, R, T_p, and scale factor for collapse capacity prediction of RC SMRFs. Moreover, the multiobjective particle swarm optimization algorithm is applied to improve the efficiency and sufficiency of some advanced scalar IMs, and an optimal scalar IM is proposed.     

A mixing‐length‐scale‐based analytical model for predicting velocity profiles of open‐channel flows with submerged rigid vegetation

In open‐channel flows with submerged vegetation, the vertical velocity profile can often be described by two layers: the vegetation layer in the lower region and the surface layer in the upper non‐vegetated region. In this paper, a new mixing‐length scale of eddy is proposed for predicting the vertical velocity profile of flow in an open‐channel with submerged rigid vegetation. The analytical model of velocity profile is based on the momentum equation of flow where the turbulent eddy viscosity is assumed to have a linear relationship with the local velocity. The proposed model was tested against different datasets from the literature. The 22 datasets used cover a range of submergence [flow depth (H)/vegetation height (h) = 1.25 ~ 3.38], different vegetation densities of ah = 0.11 ~ 1.85 (a defined as the frontal area of the vegetation per unit volume) and bed slopes (S_o = 1.8 × 10^?6 ~4.0 × 10^?3). This study showed that the proposed model can predict the velocity profiles well against all datasets, and that the mixing length scale of eddies (λ) is well related with both vegetation height (h) and flow depth of surface layer (i.e. the height of non‐vegetation layer, H–h). Close examination of λ in the proposed model showed that when λ = 0.03, the model predicts vertical velocity profiles well for all datasets used except for very shallow submergence (i.e. H/h < 1.5).     

Detoxification of seawater used for gas scrubbing in the steel industry

Cyanide ion present in seawater after scrubbing blast furnace and coke ovens gases can be removed by sedimentation of hexacyanoferrate complexes followed by oxidation of residual cyanide with Caro's acid. Zinc ion is removed at the same time by adsorption on the hexacyanoferrate/hydrous ferric oxide precipitate.Sulphide is precipitated as ferrous sulphide, then oxidised by atmospheric oxygen. At 25°C and using an Fe/CN ratio of 1·00, initial concentrations of 50 mg l⁻¹ of CN⁻ and 10 mg l⁻¹ of Zn²⁺ in seawater are reduced to 5–7 mg l⁻¹ and 0·1 mg l⁻¹. Subsequent treatment with H₂SO₅/CN = 1·2 reduces the [CN⁻] to 0·1 mg l⁻¹.Treatment of a combined blast furnace/coke ovens effluent ([CN⁻] = 24 mgl⁻¹, [Zn²⁺] = 4·0 mgl⁻¹) with Fe/CN = 1·5 reduced [CN⁻] to 0·2 mg l⁻¹ and [Zn²⁺] to <0·1 mgl⁻¹. Subsequent treatment with H₂SO₅/CN = 2·0 reduced [CN⁻] to 0·2 mg l⁻¹. The process operates best in the pH range 7–9 and so is not affected by the buffer characteristics of seawater.     

A Microcomputer-Based Geographic Information System for Hydrologic Simulation

Abstract: A microcomputer-based geographic information system (GIS) supporting hydrologic simulation is described. The hydrologically-oriented GIs can automatically provide parameters required for prediction of flood hydroghraphs and physically-based synthetic flood frequency curves for ungaged watersheds. The hydrologic model uses the Soil Conservation Service (SCS) runoff curve number (CN) method and a synthetic unit hydrograph to represent the physical transformation of rainfall into runoff The standard SCS method was modified to account for randomness of key parameters whose probability distributions can be derived from regional rainfall and runoff data. The GIs, and hydrologic theory and techniques, including the modified SCS method, derivation of a regional dimensionless unit hydrograph, and Monte Carlo simulation procedure, are described. Results of hydrologic analysis and simulation by the system implemented for an area of 11000 km² in the Alberta foothills are presented.     

Improved calibration of a rainfall‐pollutant‐runoff model using turbidity and electrical conductivity as surrogate parameters for total nitrogen

To address data scarcity for calibration of rainfall‐pollutant‐runoff (RPR) models, we evaluated the suitability of nutrient levels estimated based on surrogate parameters as a novel source of data, using runoff of total nitrogen (TN) in the Tegiru basin as a case study. A linear regression equation was developed for estimating TN based on turbidity and electrical conductivity; this expression was then used to generate TN data (n = 113) for calibration of a catchment‐specific RPR model. Using solely the estimated TN concentrations for calibration, the model accurately predicted TN concentrations (21% error based on measured TN, n = 13) and revealed runoff trends during periods in which TN measurements were lacking. Finally, we utilised this model to show that TN runoff was highest during months with frequent and high intensity rainfall. In summary, this study demonstrates the applicability of surrogate parameters to extend data on difficult‐to‐monitor nutrient loads for model calibration.     

Automated classification of near‐fault acceleration pulses using wavelet packets

This study proposes a new algorithm for automatically classifying two types of velocity‐pulses that are integral of a distinct acceleration pulse (acc‐pulse) or a succession of high‐frequency one‐sided acceleration spikes (non‐acc‐pulse). For achieving this, wavelet packet transform is used to filter the high‐frequency content and to extract the coherent velocity‐pulse. Then, the pulse period is unequivocally derived through the peak point method. Following the determination of the pulse‐starting (t_s) and pulse‐ending (t_e) time instants in the velocity time‐history, a local acceleration time‐history truncated by t_s and t_e is obtained. The maximum relative energy of the pulse between two adjacent zero crossings is then employed as indicator for distinguishing the two types of velocity‐pulses. The criteria for identifying acc‐pulses and non‐acc‐pulses are calibrated using a training data set of manually classified ground motions from the Next Generation Attenuation West 2 project. Finally, significance of such a classification between velocity‐pulses of different characteristics is assessed through the comparison of elastic acceleration response spectra of the two categories of pulse‐like records.     

Novel mold‐resistant building materials impregnated with thermally reduced nano‐silver

In this study, we evaluated the long‐term antifungal effectiveness of 3 types of interior building materials (gypsum board [GB], cement board [CB], and softwood plywood [S‐PW]) impregnated with thermally reduced silver nanoparticles supported by titanium dioxide (AgNPs/TiO₂) under 95% relative humidity for 4 weeks. AgNPs/TiO₂ was synthesized at 2 thermal reduction temperatures (TRTs, 120 and 200°C) with 2 different AgNP weight percentages (2 and 5 wt%). Four different silver‐loading levels (SLLs, 0.025, 0.05, and 0.5 μg/cm² and the critical concentration required to inhibit fungal growth on agar plates) and 3 fungal species (Aspergillus niger, Penicillium spinulosum, and Stachybotrys chartarum) were used in the experiments. Higher temperature reduced more ionic Ag⁺ to metallic Ag⁰ and increased the dispersion of Ag on TiO₂ surface. The 200°C thermally reduced AgNPs/TiO₂ demonstrated excellent antifungal efficiency: Mold growth was almost completely inhibited for 28 days at the low SLL of 0.5 μg/cm². Additionally, AgNPs/TiO₂ exhibited higher antifungal activity on GB and CB than on S‐PW. The stepwise regression results indicated that the TRT of AgNPs/TiO₂ (β = ?0.739 to ?0.51), the SLL (β = ?0.477 to ?0.269), and the Ag⁰ level in the AgNPs (β = ?0.379 to ?0.136) were the major factors influencing antifungal activity and TRT might be the most significant one.     

Biodegradation of chlorpyrifos and 3, 5, 6‐trichloro‐2‐pyridinol by a novel rhizobial strain Mesorhizobium sp. HN3

A chlorpyrifos (CP) and 3,5,6‐trichloro‐2‐pyridinol (TCP) degrading bacterial strain, Mesorhizobium sp. HN3, was isolated and characterized. Mesorhizobium sp. HN3 degraded CP efficiently up to 400 mg/L initial concentration at wide range of temperatures (30–40°C) and pH (6.0–8.0). However, optimal degradation of CP was achieved at 37°C and neutral pH (7.0) at an initial inoculum density 2 × 10⁷ colony forming unit/mL of culture medium. Kinetic parameters for CP degradation by Mesorhizobium sp. HN3 were estimated at different initial concentrations. Cultures exhibited significant variation (P ≤ 0.05) in the specific growth rate (μ), cell mass formation rate (Q_X) and the substrate uptake rate (Q_S) during degradation of CP. The values of kinetic parameters increased up to 100 mg/L CP and decreased at higher concentration. Investigation of degradation metabolites indicated that CP is converted to diethylthiophosphate and TCP that leads to the formation of 3,5,6‐trichloro‐2‐methoxypyridine.     

Pilot study of high‐performance air filtration for classroom applications

A study was conducted to investigate the effectiveness of three air purification systems in reducing the exposure of children to air contaminants inside nine classrooms of three Southern California schools. Continuous and integrated measurements were conducted to monitor the indoor and outdoor concentrations of ultrafine particles (UFPs), fine and coarse particulate matter (PM_2.5 and PM₁₀, respectively), black carbon (BC), and volatile organic compounds. An heating, ventilating, and air conditioning (HVAC)‐based high‐performance panel filter (HP‐PF), a register‐based air purifier (RS), and a stand‐alone air cleaning system (SA) were tested alone and in different combinations for their ability to remove the monitored pollutants. The combination of a RS and a HP‐PF was the most effective solution for lowering the indoor concentrations of BC, UFPs, and PM_2.5, with study average reductions between 87% and 96%. When using the HP‐PF alone, reductions close to 90% were also achieved. In all cases, air quality conditions were improved substantially with respect to the corresponding baseline (preexisting) conditions. Data on the performance of the gas‐absorbing media included in the RS and SA unit were inconclusive, and their effectiveness, lifetime, costs, and benefits must be further assessed before conclusions and recommendations can be made.     

Bacteria in a water‐damaged building: associations of actinomycetes and non‐tuberculous mycobacteria with respiratory health in occupants

We examined microbial correlates of health outcomes in building occupants with a sarcoidosis cluster and excess asthma. We offered employees a questionnaire and pulmonary function testing and collected floor dust and liquid/sludge from drain tubing traps of heat pumps that were analyzed for various microbial agents. Forty‐nine percent of participants reported any symptom reflecting possible granulomatous disease (shortness of breath on exertion, flu‐like achiness, or fever and chills) weekly in the last 4 weeks. In multivariate regressions, thermophilic actinomycetes (median = 529 CFU/m²) in dust were associated with FEV₁/FVC [coefficient = ?2.8 per interquartile range change, P = 0.02], percent predicted FEF_25–75% (coefficient = ?12.9, P = 0.01), and any granulomatous disease‐like symptom [odds ratio (OR) = 3.1, 95% confidence interval (CI) = 1.45?6.73]. Mycobacteria (median = 658 CFU/m²) were positively associated with asthma symptoms (OR = 1.5, 95% CI = 0.97?2.43). Composite score (median = 11.5) of total bacteria from heat pumps was negatively associated with asthma (0.8, 0.71?1.00) and positively associated with FEV₁/FVC (coefficient = 0.44, P = 0.095). Endotoxin (median score = 12.0) was negatively associated with two or more granulomatous disease‐like symptoms (OR = 0.8, 95% CI = 0.67?0.98) and asthma (0.8, 0.67?0.96). Fungi or (1→3)‐β‐D‐glucan in dust or heat pump traps was not associated with any health outcomes. Thermophilic actinomycetes and non‐tuberculous mycobacteria may have played a role in the occupants' respiratory outcomes in this water‐damaged building.     

Fatigue damage analysis of reinforced concrete column considering low‐cycle behavior of HRB400 steel

In this study, a damage model‐based fatigue behavior is proposed. To consider the fatigue behavior of steel in the damage model, the experimental research on reinforcing steel bar grades HRB400 was presented. The monotonic tension test and low‐cycle fatigue test were carried out. The plastic strain amplitude–fatigue cycle (ε_p–2N_f) curve and plastic strain amplitude–strength loss factor (ε_p–?_SR) curve were obtained. The fatigue parameters (C_f, C_d, and α) were proposed by nonlinear fitting. The specimens were simulated using the “Reinforcing Steel” material in “OpenSees” program. These fatigue parameters were proved to accurately describe the fatigue behavior of HRB400 rebar. Moreover, to verify the application of fatigue damage model in RC column, fiber‐based element models were established based on the quasi‐static cyclic test on RC columns. The calculated results agreed well with those of the tests. The damage degree of RC column was calculated by the recorded stress–strain curves of material. The proposed fatigue parameters could be referred in damage model based on material fatigue behavior.     

Adaptation of the Natural Resources Conservation Service (NRCS) curve number (CN) model in estimating direct run‐off from humid tropical forest catchments

Suitability of the Natural Resources Conservation Service (NRCS) curve number (CN) model of run‐off prediction was evaluated on three humid tropical forested catchments in Kimakia, Kenya. The catchments were dominated by Pinus patula (catchment A), Arundinaria alpina (catchment C) and Pennisetum clandestinum (catchment M). The study used discharge and rainfall data collected between 1958 and 1986. Seventy‐three (73) isolated storms were graphically separated into baseflow, interflow and surface run‐off. Forest cover types significantly improved catchments characteristics that influence baseflow and interflow generation in catchment C but not those that influence surface run‐off production. In its original form, the NRCS CN model resulted in direct run‐off estimates that deviated from observed ones by between 43.8% and 55.3%. These discrepancies were minimized through modification of the β and CN parameters. CN generated empirically using storm rainfall predicted the direct run‐off satisfactorily. Therefore, the modified NRCS CN model adequately estimates direct run‐off from humid tropical forested catchments.     

Predicting the importance of oxidative aging on indoor organic aerosol concentrations using the two‐dimensional volatility basis set (2D‐VBS)

Organic aerosol (OA) is chemically dynamic, continuously evolving by oxidative chemistry, for instance, via hydroxyl radical (OH) reactions. Studies have explored this evolution (so‐called OA aging) in the atmosphere, but none have investigated it indoors. Aging organic molecules in both particle and gas‐phases undergo changes in oxygen content and volatility, which may ultimately either enhance or reduce the condensed‐phase OA concentration (C_OA). This work models OH‐induced aging using the two‐dimensional volatility basis set (2D‐VBS) within an indoor model and explores its significance on C_OA relative to prior modeling methodologies which neglect aging transformations. Lagrangian, time‐averaged, and transient indoor simulations were conducted. The time‐averaged simulations included a Monte Carlo procedure and sensitivity analysis, using input distributions typical of U.S. residences. Results demonstrate that indoors, aging generally leads to C_OA augmentation. The extent to which this is significant is conditional upon several factors, most notably temperature, OH exposure, and OA mass loading. Time‐averaged C_OA was affected minimally in typical residences (<5% increase). However, some plausible cases may cause stronger C_OA enhancements, such as in a sunlit room where photolysis facilitates significant OH production (~20% increase), or during a transient OH‐producing cleaning event (~35% peak increase).     

Non‐steroidal anti‐inflammatory pharmaceutical wastewater treatment using a two‐chambered microbial fuel cell

The two‐chambered microbial fuel cell (MFC) was designed and used for studying the efficiency of the real wastewater treatment from a non‐steroidal anti‐inflammatory pharmaceutical plant as well as from synthetic wastewater containing diclofenac sodium (DS). The removal of the contaminants was expressed regarding chemical oxygen demand (COD) removal, as measured by spectrophotometry experiments. Moreover, the effect of two different types of the cathode on current characteristics and COD removal was investigated. This research showed that the Pt‐coated Ti cathode could lead to higher efficiency of both power density and COD removal. In this case, the results indicated that the maximum power density (P_max) was 20.5 and 6.5 W/m³ and the maximum COD removal was 93 and 78% for MFCs using real and synthetic wastewater, respectively.