Search

Tannic acid is known as one of the refractory organic pollutants in water. Amino-functionalized magnetic nanoadsorbent (Fe3O4@SiO2-NH2) exhibited high adsorption capacity for aqueous TA with maximum adsorption amount of 136.23 mg/g at 25 °C. TA adsorption on the adsorbent could be well described by Langmuir adsorption model and the adsorption process was endothermic. Furthermore, pseudo-second adsorption kinetics can fit TA adsorption data very well, and the adsorption rate decreased with increasing initial TA concentration. The presence of Na+, K+, and Ca2+ may result in enhanced TA adsorption. In addition, TA adsorption over the adsorbent was highly dependent on solution pH and the maximum adsorption amount was found to be at pH 6.0. The XPS analysis revealed that TA adsorption over the adsorbent may be attributed to the surface complexation between the amino groups of the adsorbent and TA in solution. The TA loaded adsorbent can be effectively desorbed in a 0.5 M HCl solution, and the regenerated adsorbent can be recycled.

Tank-to-Wheels (TtW) makes the largest contribution to the total Well-to-Wheels (WtW) energy consumption and greenhouse gas (GHG) emissions from fossil-derived transportation fuels. The most commonly adopted TtW methodologies to obtain vehicle energy consumption, energy efficiency, and GHG emissions used to date all have significant limitations. A new TtW methodology, which combines micro-scale virtual vehicle simulation with macro-scale fleet modeling, is proposed in this paper. The models capabilities are demonstrated using a case study based on data from the passenger car sector in Great Britain. A simplified internal combustion engine model was developed in-house to simulate engine behaviors across a wide range of engine capacities and technologies. Vehicle simulation was then carried out using the efficiency map output by the simplified engine model for any given gasoline or diesel engine; the simulation was validated for 37 vehicles available on the UK market in terms of their vehicle-certification fuel consumption, with a discrepancy generally within 3%. Real-world fleet and driving data from the Great Britain’s car fleet was extracted from the Transport Statistics Great Britain (TSGB) database between 2001 and 2007TSGB 2001–2007. A virtual fleet was constructed with the validated virtual vehicles to represent the real-world passenger car fleet in terms of its composition and operating characteristics. This fleet model was shown to match the real-world fleet-averaged fuel consumption within 3% for the gasoline fleet and within 6% for the diesel fleet. Finally, several scenarios were analyzed using the validated fleet model, covering a projection for 2008, driving pattern, lubrication, and fuel. The vehicle-to-vehicle variation was found to be significant in some scenarios, indicating that a fleet-based methodology would be more rigorous and flexible. Energy consumption and CO2 emission figures from previous, well-recognized Europe-oriented studies (e.g., the 2008 JRC/EUCAR/CONCAWE study) were significantly lower than the TSGB real-world results based on the new TtW methodology. It is apparent that using a single vehicle to represent the whole fleet could be misleading; in particular, the relative energy efficiency and CO2 emission of diesel over gasoline cars might follow a different trend with time for the real-world fleet from that shown in previous studies. Future WtW studies can benefit from the modeling toolset and methodology reported herein in a number of ways: The virtual engine/vehicle/fleet model developed in this work can readily be expanded and upgraded in the future, in terms of model details, coverage, and data quality. The methodology itself is generically applicable to any defined fleet (passenger cars, commercial vehicles, etc.) with any operating characteristics at any given timeframe from any geographic region. Various subjects and their implications for fleet energy consumption and GHG emissions could be studied including, but not restricted to, the following

Heavy metal pollution and their fractionations in the sediments of Changjiang River in Nanjing Reach was monitored for cadmium (Cd), lead (Pb), zinc (Zn), chromium (Cr), and copper (Cu). Moreover, the biological enrichment of metals by riverine plants was studied. The results demonstrated there were highly significant variations among different sampling stations for the concentrations of tested metals. The highest range was for Cu (38.8–120.4 mg kg−1), followed by Cr (74.4–120.0 mg kg−1), Zn (80.9–121.1 mg kg−1), Ni (26.0–55.5 mg kg−1), Pb (15.8–46.7 mg kg−1) and Cd (0.28–0.48 mg kg−1). Cd was the element with highest biological enrichment factor (BEF). The highest BEF of Cd in Erigeron bonariensis reached 3.0, indicating a significant Cd enrichment in this aquatic plant. In addition, 60% of Cd was found in reducible fraction and exchangeable and acid-soluble fraction, which was consistent with its high mobility. The consistency of Cd fraction in sediment and suspended particle indicated they came from the same source. Accumulated Cd concentration calculated according to the release curve showed significant relativity with the total Cd concentration in the sediment.

Background: Patellar instability is a common problem. It is unclear that the medial and lateral patellar retinaculum respective effect on patella. The purpose of this study was to evaluate the synergistic effect of medial and lateral patellar retinaculum on the stability of patella. Methods: Eight cadaveric knees were collected. Each of them was performed on patellofemoral joints under five conditions, including normal condition (Group N) and experimental conditions (Group M1, L1, L2, and M2). In Group M1, 2 kg was forced on the normal medial patellofemoral joint using a homemade knee joint immobilization apparatus. In Group L1, 2 kg was forced on the normal lateral patellofemoral joint. In Group L2, the medial retinaculum and the capsule were separated, and the lateral patellar border endured a force of 2 kg. In Group M2, the dissected medial soft tissues were sutured in-situ, and then the lateral retinaculum and the capsule were separated, and the medial patellar border endured a force of 2 kg. Evaluations included CT scan, and the scanned images of these five groups were analyzed for patellar tilt angle (PTA) and the lateral patellar displacement (LPD) values. Results: PTA (°) and LPD (mm) of Group M1 and Group L1 were not significantly different compared to Group N (P≥0.01). PTA values and LPD values of Group L2 and Group M2 increased significantly compared to Group N (P≤0.01). PTA and LPD values of Group L2 showed significant differences compared to Group M2 (P≤0.01). Conclusions: Medial patellar retinaculum prevents LPD and lateral patellar tilt. Lateral patellar retinaculum plays an important role to prevent medial patellar tilt. Medial and lateral retinaculum show synergistic effect to stabilize the patella.

Conventional methods for investigating heavy metal contamination in soil are time consuming and expensive. In this study, we (i) explored reflectance spectroscopy as an alternative method for assessing heavy metals, and (ii) further explored the physicochemical mechanism that allows estimation of heavy metals with the reflectance spectroscopy method. We first investigated the spectral response of changing concentrations of heavy metals in soils. The results indicated that only at very high concentration can transition elements exhibit their inherent absorption features. In spite of this observation, we successfully predicted low levels of heavy metals in agricultural soils. The best prediction accuracies were obtained for the siderophile elements Ni, Cr, and Co. The poorest prediction was for Cd. The order of prediction accuracy for metals was approximately the same as the order of their correlation coefficients with Fe. Complementary to some previous studies that found that the intercorrelation between heavy metals and active soil components (such as Fe oxides, organic matter, and clay) is the major predictive mechanism, in the present study we concluded that the correlation with total Fe (including active and residual Fe) is the major mechanism. This conclusion was further supported by both correlation analysis and chemical sequential extraction. Correlation analysis showed that all metals are negatively correlated with reflectance while positively correlated with the absorption depth at about 500 nm, a feature resulting from goethite. The chemical forms of heavy metals, which showed that besides the crystalline Fe oxide and organic matter fractions, heavy metals have significant amounts in the residual fraction, also strengthened the conclusion.

Tannery sludge contained plenty of organic matter, and the organic substance stability had direct impact on its derived chars’ utilization. In this paper, the stabilization of tannery sludge and the variation of humic acid-like (HAL) extracted by different methods were investigated in a magnetic stirring reactor under low temperature pyrolysis of 100–400 °C. Results showed that the aromatic structure of pyrolysis chars increased with the increase of temperature and time. The char contained highly aromatic structure and relatively small dissolved organic matters (DOM) at 300 °C. The similar behaviors appeared in two HAL series by different extraction methods. The N content, H/C value, and aliphatic structures of HAL decreased with the increase of pyrolysis temperature, while the C/N value and aromatic structures increased with the rise of pyrolysis temperature. The composition and functional groups of HAL were similar with the purchased humic acid (HA). The fluorescence spectra revealed that two main peaks were found at Ex/Em = 239/363–368 nm and 283/359–368 nm in each HAL series from raw and 100 °C pyrolysis tannery sludge, representing a protein-like matter. The new peak appeared at Ex/Em = 263–283/388 nm in each HAL series from 200 °C pyrolysis tannery sludge-represented humic acid-like matter. The fluorescence intensity increased strongly compared to the other two peak intensity. Therefore, the humification of organic matter was increased by pyrolyzing. Notably, the HAL from 200 °C pyrolysis tannery sludge contained simple molecular structure, and the polycondensation increased but with a relative lower humification degree compared to soil HAL and purchased HA. Therefore, the sludge needs further oxidation. The humic substance was negligible by direct extraction when the temperature was 300 and 400 °C.

An investigation was carried out into the crop uptake of Cr(III) and its accumulation in two alkaline soils that have received tannery sludge as organic fertilizer for many years. The Cr(III) conce...

The European “Community Bureau of Reference” (BCR) sequential extraction procedure, diffusive gradient in thin-films technique (DGT), and physiologically based extraction test were applied to assess metal bioavailability in sediments of Lake Taihu (n = 13). Findings from the three methods showed that Cd was a significant problem in the western lake whereas Cu, Zn, and Ni pollution was most severe in the northern lake. Results from the sequential extraction revealed that more than 50 % of the Cu and Zn were highly mobile and defined within the extractable fraction (AS1 + FM2 + OS3) in the majority of the sediments, in contrast extractable fractions of Ni and Cd were lower than 50 % in most of the sampling sites. Average Cu, Zn, Ni, and Cd bioaccessibilities were

Precipitate adsorbent was produced from aluminum tanning wastewater by alkali precipitation and characterized by XPF, XRD, and FTIR. The results showed that the main components of the precipitate were Al, Ti, and Zr. The adsorption equilibrium for Cr3+ on the precipitate was reached within 60 min. The precipitate had better removal for Cr3+ from wastewater at pH 7.0. The kinetic process of adsorption can be described by the pseudo-second-order kinetic equation, and the adsorption isotherm fitted to the Langmuir model very well. Co-existed cations (Na+, Ca2+) in aqueous solution restrained Cr3+ adsorption on the precipitate. The adsorption of Cr3+ on the precipitate was mainly through the complexation and ion-exchange mechanisms, and oxide may play a major role in Cr3+ adsorption process.

Magnetically separable polyaniline (Fe 3 O 4 @SiO 2 –PANI) was prepared by in situ chemical polymerization of aniline on the surface of silica-coated Fe 3 O 4 nanoparticles, and characterized by FTIR spectroscopy, powder X-ray diffraction, elemental analysis, transmission electron microscopy, vibrating sample magnetometry and X-ray photoelectron spectroscopy. Characterization results showed that Fe 3 O 4 @SiO 2 –PANI with amino groups of 1.78 mmol/g and the average diameter of 21.6 nm are superparamagnetic. Adsorption behavior of Fe 3 O 4 @SiO 2 –PANI nanoparticles for humic acid (HA) was investigated by batch experiments and adsorption kinetic tests. HA adsorption amount on the adsorbent decreased with increasing solution pH and the presence of Ca 2+ resulted in the enhanced HA adsorption. HA adsorption on Fe 3 O 4 @SiO 2 –PANI could be well described by Langmuir model and the maximum adsorption amount of the adsorbent for HA at 25 °C was 36.36 mg/g. HA adsorption process on the adsorbent obey pseudo-second-order kinetics and the adsorption rates decrease with increasing initial HA concentration. The XPS analysis verified that HA adsorption over the adsorbent could be attributed to the surface complexation between the disassociated HA molecules and the protonated nitrogen of polyaniline on the adsorbent. HA loaded adsorbent could be magnetically separated and easily desorbed in 0.01 mol/L NaOH solution. Regeneration tests indicated that Fe 3 O 4 @SiO 2 –PANI could be used repeatedly.

Sediments in five national controlling sections of Weihei river in Shaanxi province have been investigated for cadmium (Cd), lead (Pb), zinc (Zn), chromium (Cr), Nickel (Ni) and copper (Cu). The results demonstrated there were highly significant variations among different sampling stations for the concentrations of tested metals. There appeared obvious Zn and Pb enrichment in sediment in all the studied area. Cd was found enrichment in one section. In addition, Pb was found in high percentages in residual fraction and oxidizable fraction, posing less threat of release to water with changing environmental conditions.

Batch adsorption procedures were conducted to remove methylene blue (MB) from aqueous solutions with fly ash (FA). The samples of FA were characterized by scanning electronic microscopy (SEM), and the effects of initial pH value, contact time, MB concentration and dosage of FA on removal efficiency were investigated. The holey characteristics and rough surface of FA made it possible to purify wastewater containing MB. It proved the reaction was fast, at the pH value of 6, the removal efficiency was optimal, lower MB concentration as well as higher dosage of FA could accelerate MB removal. The regeneration reaction on FA with 200 mL of C 3 H 6 O for 30 min was more effective than others. FA was effective in wastewater purification for MB, the ease of handling and low cost made it potential in practical application.

A study of in-cylinder fuel-air mixing distributions in a firing gasoline-direct-injection engine is reported using planar laser-induced fluorescence (PLIF) imaging. A multi-component fuel synthesised from three pairs of components chosen to simulate light, medium and heavy fractions was seeded with one of three tracers, each chosen to co-evaporate with and thus follow one of the fractions, in order to account for differential volatility of such components in typical gasoline fuels. In order to make quantitative measurements of fuel-air ratio from PLIF images, initial calibration was by recording PLIF images of homogeneous fuel-air mixtures under similar conditions of in-cylinder temperature and pressure using a re-circulation loop and a motored engine. This calibration method was found to be affected by two significant factors. Firstly, calibration was affected by variation of signal collection efficiency arising from build-up of absorbing deposits on the windows during firing cycles, which are not present under motored conditions. Secondly, the effects of residual exhaust gas present in the firing engine were not accounted for using a calibration loop with a motored engine.In order to account for these factors a novel method of PLIF calibration is presented whereby 'bookend' calibration measurements for each tracer separately are performed under firing conditions, utilising injection into a large upstream heated plenum to promote the formation of homogeneous in-cylinder mixtures. These calibration datasets contain sufficient information to not only characterise the quantum efficiency of each tracer during a typical engine cycle, but also monitor imaging efficiency, and, importantly, account for the impact of exhaust gas residuals (EGR). By use of this method EGR is identified as a significant factor in quantitative PLIF for fuel mixing diagnostics in firing engines.The effects of cyclic variation in fuel concentration on burn rate are analysed for different fuel injection strategies. Finally, mixture distributions for late injection obtained using quantitative PLIF are compared to predictions of computational fluid dynamics calculations. © 2010 The Combustion Institute.

Six stations in the lower reach region of Changjiang River within Baguazhou Island, Nanjing reach were chosen to investigate the toxic metals pollution characteristic in suspended particle material (SPM). SPM concentration, as well as reflectance spectroscopy characteristic, toxic metal concentrations, and lead isotopes of suspended particle material were studied. SPM concentrations were obtained from fluvial cross-sectional sampling near the surface (20 cm) and the study presents the cross-sectional averages. SPM concentrations varied around 170–300 mg L − 1. Reflectance spectroscopy measurements differed from each other over each cross-section but no common pattern characterizing the cross-sectional behavior of the measurements was observed. The metal concentrations in the SPM decreased in the sequence: Mn > Zn > Cu > Cr > Pb > Cd. The result of lead isotopes analysis proved that lead isotopes composition in SPM are mainly produced by natural contributions and influenced by anthropogenic activity at the same time.

Planar Laser-Induced Fluorescence has been widely accepted and applied to measurements of fuel concentration distributions in IC engines. The need for such measurements has increased with the introduction of Direct Injection (DI) gasoline engines, where it is critical to understand the influence of mixture inhomogeneity on ignition and subsequent combustion, and in particular the implications for cyclic variability. The apparent simplicity of PLIF has led to misunderstanding of the technique when applied to quantitative measurements of fuel distributions. This paper presents a series of engineering methods for optimizing, calibrating and referencing, which together demonstrate a quantitative measure of fuel concentration with an absolute accuracy of 10%. PLIF is widely used with single component fuels as carriers for the fluorescent tracers. This paper shows that this method inadequately describes a real fuel spray, and presents instead a method that uses a fully fractionated multi-component fuel for PLIF diagnostics. A series of measurements is presented of fuel distribution, early injection DI homogeneity and cyclic variation of injector plumes in a DI single cylinder optical research engine. Copyright © 2008 SAE International.

The measurement of in-cylinder, combustion-generated nitric oxide using degenerate four-wave mixing (DFWM) in a firing, methane-fueled research engine is reported. An optical arrangement for producing DFWM in the forward geometry is described that results in reliable signal generation with excellent signal-to-noise ratio from the skip-fired engine. DFWM signals from temperature-insensitive lines were used to infer variations in NO concentration at the end of the expansion stroke at exhaust valve opening. The variation in NO concentration inferred from the DFWM signals was measured as a function of equivalence ratio and ignition timing indicated by peak pressure values. These measurements using DFWM were compared to measurements using line-of-sight optical absorption and a chemiluminescence exhaust gas analyzer. Good agreement was found for all three measurements. The results demonstrate the potential for DFWM to make quantitative spatially and temporally resolved measurements in a firing spark-ignition engine. © 2006 The Combustion Institute.

Color-ratio pyrometry (CRP) is a technique for estimating the temperature and loading of soot, based on its thermal emission spectrum. This technique is contrasted with conventional two-color pyrometry which requires absolute measurements of the radiation intensity, either at two specific wavelengths or ranges of wavelengths. CRP uses two ratios, obtained by measuring the radiation intensity for three wavelengths or wavelength bands. CRP has been implemented here by using a digital CCD camera, and full details of the calibration are reported. Because of uncertainties in the emissivity of reference sources (such as tungsten ribbon lamps, in which the emissivity depends on temperature and wavelength), then a spectroscopic calibration of the CCD camera has been used. Use of a CCD camera is not straightforward because of internal digital signal processing (DSP), so full details are given of the calibration and technique implementation. Calibration results, together with an error analysis, showed an accuracy of ±50K within the combustion temperature range and a preference for the temperature estimates based on the red/green ratio over the red/blue ratio at low temperatures and the red/blue ratio over the red/green ratio at high temperatures. Temperature estimates are shown to be insensitive to the concentration of soot. Combustion imaging was later carried out on a sprayguided direction injection spark ignition engine with optical access. Temperature estimates under various imaging timings and mixture strengths are presented. With a fixed operating point the maximum in-cylinder temperature occurred just after top center, and this coincided with the maximum rate of heat release. When the mixture strength was varied, the maximum temperature (at a particular crank angle) was rich of stoichiometric. Finally, temperature and KL results using the variable KL algorithm were reported together with discussions about soot formation.

A technique has been developed for full bore imaging, and a high speed video camera used to obtain images that have been processed for soot temperature and loading, and flame growth. The soot measurements have been made with a colour ratio technique that avoids the need for an in-situ absolute radiation calibration. Instead, the spectral response of the camera has to be determined for each of the red, green and blue channels. Planar Laser-Induced Fluorescence (PLIF) has been extensively used for visualizing species of combustion and reacting flows. However, the relationship between PLIF signal strength and species concentration is complicated by other dependencies, so careful calibration is essential. In order to study the effects of evaporation of a multi-component fuel in an IC engine, a gasoline-like component fuel has been devised which has three components of low, medium and high-volatility. Each component is made from two non-fluorescing constituents chosen so that the component (as a whole) will co-evaporate with one of three selected tracers: namely acetone, toluene or 1,2,4-trimethylbenzene (TMB). Calibration results are presented along with fuel concentration distributions derived from the PLIF images that have been analyzed on a cycle-by-cycle basis. © IMechE 2007.