Inkjet printing of metal nanoparticles is an attractive method for front-side metallization of silicon solar cells. It is owing to noncontact, low-cost, low-waste, and simple process. In this work, we proposed the ink-jet printing and electroless technology to fabricate the seed layer and electrode layer, respectively. Furthermore, we used electroplating method to increase the electrode conductivity. In this way, the energy conversion efficiency up to 12.22% without AR coating can be obtained on 100 × 100 mm c-Si cell.

The aim of this study was to justify the method to determine biochemical methane potential (BMP) of biosludges and investigate the effect of ozonation and sonication on the biosludge from textile mill effluent to its biodegradability and toxicity. This study revealed that the exented anaerobic toxicity assay at a chemical oxygen demand (COD) concentration in the assay of about 1,500 mg/L was the appropiate technique to determine BMP of the biosludge. Moreover, it was found that the biodegradability of biosludge was satisfactorily increased by both of ozonation and sonication. The use of ozone dose of 0.005 g O₃/g COD and 0.01 O₃/g COD increased the biodegradability from 62% to 69% and 76%, respectively. While for sonication on frequency 51 kHz ±6%, 120 W for 30 and 60 min increased the biodegradability from 62% to 68% and 73%, respectively.

A novel method is developed to capture and analyze several experimental flow regimes through a gross pollutant trap (GPT) with fully and partially blocked screens. Typical flow conditions and screen blockages are based on findings from field investigations that show a high content of organic matter in urban areas. Fluid motion of neutral buoyant particles is tracked using a high-speed camera and particle image velocimetry (PIV) software. The recorded fluid motion is visualized through an image-based, line integral convolution (LIC) algorithm, generally suitable for large computational fluid dynamics (CFD) datasets. The LIC method, a dense representation of streamlines, is found to be superior to the point-based flow visualization (e.g., hedgehog or arrow plots) in highlighting main flow features that are important for understanding litter capture and retention in the GPT. Detailed comparisons are made between the flow regimes, and the results are compared with CFD data previously obtained for fully blocked screens. The LIC technique is a useful tool for identifying flow structures in the GPT and areas that are subjected to abnormalities difficult to detect by conventional methods. The novel method is found to be useful both in the laboratory and in the field, with little preparation and cost. The enhancements and pitfalls of the LIC technique along with the experimentally captured flow field are presented and discussed.

The promotion of good indoor air quality in schools is of particular public concern for two main reasons: (1) school-age children spend at least 30% of their time inside classrooms and (2) indoor air quality in urban areas is substantially influenced by the outdoor pollutants, exposing tenants to potentially toxic substances. Two schools in Curitiba, Brazil, were selected to characterize the gaseous compounds indoor and outdoor of the classrooms. The concentrations of benzene, toluene, ethylbenzene, and the isomers xylenes (BTEX); NO₂; SO₂; O₃; acetic acid (HAc); and formic acid (HFor) were assessed using passive diffusion tubes. BTEX were analyzed by gas chromatography-ion trap mass spectrometry and other collected gasses by ion chromatography. The concentration of NO₂ varied between 9.5 and 23 µg m⁻³, whereas SO₂ showed an interval from 0.1 to 4.8 µg m⁻³. Within the schools, BTEX concentrations were predominant. Formic and acetic acids inside the classrooms revealed intermediate concentrations of 1.5 µg m⁻³ and 1.2 µg m⁻³, respectively.

The kinetics of the adsorption of Pb²⁺ and Cd²⁺ by sodium tetraborate (NTB)-modified kaolinite clay adsorbent was studied. A one-stage and two-stage optimization of equilibrium data were carried out using the Langmuir and time-dependent Langmuir models, respectively. Increasing temperature was found to increase the pseudo-second order kinetic rate constant and kinetic data for Pb²⁺ adsorption were found to fit well with the pseudo-second order kinetic model (PSOM) while that for Cd²⁺ were found to show very good fit to the modified pseudo-first order kinetic model (MPFOM). Binary solutions of Pb²⁺ and Cd²⁺ reduced the adsorption capacity of the modified adsorbent for either metal ion with increased initial sorption rate due to competition of metal ions for available adsorption sites. The use of NTB-modified kaolinite clay adsorbent reduces by approximately 72.2% and 96.3% the amount of kaolinite clay needed to adsorb Pb²⁺ and Cd²⁺ from wastewater solutions. From the two-stage batch adsorber design study, the minimum operating time to determine a specified amount of Pb²⁺ and Cd²⁺ removal was developed. The two-stage batch adsorption process predicted less than half the minimum contact time to reach equilibrium in the one-stage process for the adsorption of Pb²⁺ and Cd²⁺ by NTB-modified kaolinite clay adsorbent and requires 0.05 times the mass of the adsorbent for the single-stage batch adsorption at the same operating conditions.

pH monitoring data for public water bodies in Niigata and Gifu prefectures in central Japan were tested by the nonparametric seasonal Mann-Kendall method to evaluate long-term acidification. A significant long-term declining trend in river water pH was found in several watersheds in Niigata and Gifu prefectures. In Niigata, the declining trend was observed only in areas receiving drainage from granitic rocks, and the acid neutralizing capacity of the river waters was in fact low in those areas. In Gifu, a declining trend was observed in some remote watersheds, where there was no clear relationship between the geology and the long-term trends. Since Niigata and Gifu receive the highest level of acid loading from the atmosphere in Japan, river water acidification in several watersheds may be attributable to the effects of the acid deposition. Other factors, such as hot spring drainage, changes in land use, and natural sea salt deposition, cannot adequately explain the acidification phenomena observed in this study.

We report observations of primary and secondary atmospheric pollutants such as nitrogen oxides, sulfur dioxide, toluene, and ozone during the period February 2002 to August 2003 in Puertollano, an industrial area located in central-southern Spain. The measurements were performed using a commercial differential optical absorption spectroscopy instrument. From the hourly data, we have analyzed the mean seasonal levels and the daily evolution and we have examined the occurrence of elevated pollution episodes. The daily cycles of NO, NO₂, SO₂, and toluene were characterized by an early-morning maximum whereas O₃ peaks were monitored around noon. Seasonally, the highest hourly mean concentrations of NO, NO₂, SO₂, and toluene, 14.2, 27.0, 34.4, and 12.1 μg m⁻³ respectively, were found in the winter while O₃ summer levels reached 119.1 μg m⁻³. The dataset presented here shows episodic occurrences of elevated concentrations that exceeded the maximum levels established in the European Directives. For instance, hourly values for SO₂ were repeatedly measured above 350 μg m⁻³. During the period of measurements, the O₃ thresholds (i.e., hourly value of 240 μg m⁻³) defined to protect the human health have also been exceeded numerous times. Finally, we investigate daily and seasonal patterns in pollution levels within the context of local meteorology and photochemistry, vehicular traffic, and industrial emissions.

The degradation of benzene in groundwater at concentrations as high as 2,000 mg L⁻¹ was studied using a four-column trickling-flow fixed-film biological reactor with recirculation. A decrease in the content of benzene was achieved, its concentration falling to 0.55 µg L⁻¹. On the contrary, high levels of diesel fuel were not diminished sufficiently with this mode of operation of the reactor. Thus, a submerged reactor was tested as a modification to the conventional trickling-flow configuration. This modified fixed-film reactor was effective when high loadings of diesel were present as an emulsion. The concentration of diesel was reduced from 2,000 to 0.12 mg L⁻¹ after 8 days of treatment. In both cases, the reactors were packed with a carbonaceous material and were operated in semibatch mode with recirculation. The final concentration of benzene fell below the permissible limit established by Mexican law, and the results for both pollutants also met the concentration limits required by the German law for drinking water, 0.001 mg L⁻¹ for benzene and 0.1 mg L⁻¹ for total hydrocarbons.

The objectives of this study were to determine the capacity of the freshwater calanoid copepod Argyrodiaptomus falcifer (Daday, 1905) to accumulate Cr from water, to know the bioconcentration factors in order to evaluate its potential as a biomonitor, and to compare this with data previously obtained with Daphnia magna Straus under identical conditions. By static bioassays using triplicates and a control, a pool of A. falcifer was exposed to three concentrations of Cr (VI): 150 μg/L (T1), 280 μg/L (T2), and 350 μg/L (T3) for 48 h to later determine by Instrumental Neutron Activation Analysis the amount of Cr accumulated. A. falcifer accumulated Cr in all the three concentrations tested. The comparison of T1, T2, and T3 and the control showed significant differences (p < 0.05) but not between the treatments (p > 0.05). On the other hand, A. falcifer accumulated more Cr than D. magna, but these differences were not significant (p > 0.05). Almost no information is available about metal toxicity in freshwater copepods so the reported results are of high importance in order to detect good biomonitors of freshwater Cr-polluted environments.

Deep drainage technique utilised for flood mitigation in low-land coastal areas of Australia during the late 1960s has resulted in the generation of sulphuric acid in soil by the oxidation of pyritic materials. Further degradation of the subsurface environment with widespread contamination of the underlying soil and groundwater presents a major and challenging environmental issue in acid sulphate soil (ASS) terrains. Although several ASS remediation techniques recently implemented in the floodplain of Southeast Australia including operation of gates, tidal buffering and lime injections could significantly control the pyrite oxidation, they could not improve the long-term water quality. More recently, permeable reactive barriers (PRBs) filled with waste concrete aggregates have received considerable attention as an innovative, cost-effective technology for passive in situ clean up of groundwater contamination. However, long-term efficiency of these PRBs for treating acidic groundwater has not been established. This study analyses and evaluates the performance of a field PRB for treating the acidic water over 2.5 years. The pilot-scale alkaline PRB consisting of recycled concrete was installed in October 2006 at a farm of southeast New South Wales for treating ASS-impacted groundwater. Monitoring data of groundwater quality over a 30 month period were assessed to evaluate the long-term performance of the PRB. Higher pH value (~pH 7) of the groundwater immediately downstream of the PRB and higher rates of iron (Fe) and aluminium (Al) removal efficiency (>95%) over this study period indicates that recycled concrete could successfully treat acidic groundwater. However, the overall pH neutralising capacity of the materials within the barrier declined with time from an initial pH 10.2 to pH 7.3. The decline in the performance with time was possibly due to the armouring of the reactive material surface by the mineral precipitates in the form of iron and aluminium hydroxides and oxyhydroxides as indicated by geochemical modelling.