Geometric variability and surface finish of weld zones in Yb:YAG laser welded advanced high strength steels

Laser welding is used for joining advanced high strength steels (AHSS) to improve formability and performance. In this paper, the geometric variability observed in the fusion zones and heat affected zones of several combinations of AHSS (different types, coatings and thicknesses), which were butt welded using a Trumpf TRUDISK 6000^® Yb:YAG laser beam, is presented. The surface texture parameters such as roughness and waviness of laser welds were also measured and correlated with geometric variability. Results indicate that although high quality welds with minimal defects can be obtained using the Yb:YAG laser welding process, there is considerable variation in both the shape and the dimensions of weld zones. The variability increased with an increase in thickness differentials between the sheets being welded. Analysis of the top of the weld surfaces also suggested that aluminum coating on USIBOR samples contributes significantly to increased roughness. An increase in laser power coupled with corresponding increase in welding speed did not impact variability. A fair correlation between the surface roughness and weld region variability exists, although this needs further study.     

Identification and characterization of extracted microplastics from agricultural soil near industrial area: FTIR and X-ray diffraction method

Microplastics have been found in large quantities in agricultural soil and now become a major global issue. Different types of microplastic have adverse effects on agricultural soil. The most widely used method for the extraction of microplastics in agricultural soil is the density floatation method by using saturated NaCl solution. This method includes the pre-digestion of soil samples with H₂O₂ to remove all the organic matter present in the soil. Different types of microplastic particles were extracted and identified by using ATR-FTIR viz polypropylene, polybutylene tetrapthalate, polyethylene, polystyrene, and polyethylene tetrapthalate. The crystalline nature of extracted microplastic was checked by employing XRD analytical technique. Floatation with higher density saturated sodium chloride (NaCl) solution recovered approximately 80% MPs from soil. Floatation methods were found to be effective for extracting microplastics from soils.     

The Synthesis and FTIR, Kinetics and TG/DTG/DTA Study of Inter Penetrating Polymer Networks (IPNs) Derived from Polyurethanes of Glycerol Modified Castor Oil and Cardanol Based Dyes

Interpenetrating polymer networks from agricultural products such as glycerol modified castor oil polyurethanes and cardanol based dyes have not been extensively studied so far. Such polymers were synthesized using benzoyl peroxide as initiator and ethylene glycol dimethacrylate as cross-linker. Characterizations of these polymers were performed by Fourier Transform infra red spectra and thermal analysis techniques such as thermogravimetric analysis, derivative thermogravimetry and differential thermal analysis. The kinetic parameters such as activation energies and orders of reaction were estimated by using Freeman?CAnderson??s method. The effects of changes in polyurethane to dye monomer weight ratio and NCO/OH molar ratio of polyurethanes on the properties of such polymers were studied.     

Toxicological impact of anilofos on some physiological processes of a rice field cyanobacterium Anabaena torulosa

This study deals with the toxicological impact of the herbicide anilofos on photosynthesis, respiration, nitrogen assimilation, and antioxidant system in a diazotrophic rice field cyanobacterium Anabaena torulosa. Treatment of anilofos (1.25, 2.5, and 5?mg?L^?1) affected growth, photosynthetic pigments, photosynthesis, and respiration of the cyanobacterium. Although all the photosynthetic pigments were affected, a maximum effect of the herbicide was observed on phycocyanin (51% reduction) followed by the carotenoids. The effect of the herbicide on photosynthetic pigments resulted in 57% decrease in photosynthetic O₂ evolution. Studies on the photochemical activity demonstrated that both photosystems (PS I and PS II) were affected by the herbicide. Decrease in the photosynthesis rate resulted in decreased nitrogen assimilation, as revealed by reduced nitrate (20%) and ammonium (26%) uptake and decreased activities of nitrogenase (63% decrease) and glutamine synthetase (22% decrease). This ultimately resulted in the reduced growth of the organism. Activities of superoxide dismutase, catalase, and peroxidase in the presence of anilofos increased by 1.8–3.5 times over control cultures. Proline content increased by 1.6 times, while the content of ascorbate decreased slightly. These results indicate that the organism was able to tolerate the herbicide stress by activating oxidative stress defense mechanism.     

Synthesis of nanoparticles using microorganisms and their applications: a review

Environmental Chemistry Letters - Nanoparticles synthesis under green conditions has been performed using natural resources to diminish the use of toxic chemicals. For instance, microbial synthesis...     

Integrated process approach for degradation of p-cresol pollutant under photocatalytic reactor using activated carbon/TiO2 nanocomposite: application in wastewater treatment

Environmental Science and Pollution Research - Over the years, biodegradation has been an effective technique for waste water treatment; however, it has its own limitations. In order to achieve a...     

Impact of river flow modification on wetland hydrological and morphological characters

A good number of researchers investigated the impact of flow modification on hydrological, ecological, and geomorphological conditions in a river. A few works also focused on hydrological modification on wetland with some parameters but as far the knowledge is concerned, linking river flow modification to wetland hydrological and morphological transformation following an integrated modeling approach is often lacking. The current study aimed to explore the degree of hydrological alteration in the river and its effect on downstream riparian wetlands by adopting advanced modeling approaches. After damming, maximally 67 to 95% hydrological alteration was recorded for maximum, minimum, and average discharges. Wavelet transformation analysis figured out a strong power spectrum after 2012 (damming year). Due to attenuation of flow, the active inundation area was reduced by 66.2%. After damming, 524.03 km² (48.9% of total pre-dam wetland) was completely obliterated. Hydrological strength (HS) modeling also reported areas under high HS declined by 14% after post-dam condition. Wetland hydrological security state (WSS) and HS matrix, a new approach, are used to explore wetland characteristics of inundation connectivity and hydrological security state. WSS was defined based on lateral hydrological connectivity. HS under critical and stress WWS zones deteriorated in the post-dam period. The morphological transformation was also well recognized showing an increase in area under the patch, edge, and a decrease in the area under the large core area. All these findings established a clear linkage between river flow modification and wetland transformation, and they provided a good clue for managing wetlands.

     

Role of competition in phytoplankton population for the occurrence and control of plankton bloom in the presence of environmental fluctuations

Termination of harmful algal blooms (HABs) and coexistence of phytoplankton–zooplankton populations are of great importance to human health, ecosystem, environment, tourism and fisheries. In this paper, we propose a three component model consisting of non-toxic phytoplankton (NTP), toxin producing phytoplankton (TPP) and zooplankton (Z). The growth of zooplankton species is assume to reduce due to toxic chemicals released by TPP population. We have extended the model proposed by Chattopadhyay et al. [Chattopadhyay, J., Sarkar, R.R., Pal, S., 2004. Mathematical modelling of harmful algal blooms supported by experimental findings. Ecol. Comp. 1, 225–235] by including competition terms between TPP and NTP. We observe the effect of competition factors both in the presence and absence of the environmental fluctuation. From our field as well as model analysis we observe that competition helps in the coexistence of the species, but if the effect of competition is very high on the TPP population, it results in planktonic bloom. It is shown that the coexistence equilibrium loses its stability when the competition coefficient crosses a critical value and resulting Hopf-bifurcation around the positive equilibrium depicting oscillations phenomena of the populations.     

Characterizing ammonia emissions from swine farms in eastern North Carolina: part 1--conventional lagoon and spray technology for waste treatment

Ammonia (NH3) fluxes from waste treatment lagoons and barns at two conventional swine farms in eastern North Carolina were measured. The waste treatment lagoon data were analyzed to elucidate the temporal (seasonal and diurnal) variability and to derive regression relationships between NH3 flux and lagoon temperature, pH and ammonium content of the lagoon, and the most relevant meteorological parameters. NH3 fluxes were measured at various sampling locations on the lagoons by a flowthrough dynamic chamber system interfaced to an environmentally controlled mobile laboratory. Two sets of open-path Fourier transform infrared (FTIR) spectrometers were also used to measure NH3 concentrations for estimating NH3 emissions from the animal housing units (barns) at the lagoon and spray technology (LST) sites. Two different types of ventilation systems were used at the two farms. Moore farm used fan ventilation, and Stokes farm used natural ventilation. The early fall and winter season intensive measurement campaigns were conducted during September 9 to October 11, 2002 (lagoon temperature ranged from 21.2 to 33.6 degrees C) and January 6 to February 2, 2003 (lagoon temperature ranged from 1.7 to 12 degrees C), respectively. Significant differences in seasonal NH3 fluxes from the waste treatment lagoons were found at both farms. Typical diurnal variation of NH3 flux with its maximum value in the afternoon was observed during both experimental periods. Exponentially increasing flux with increasing surface lagoon temperature was observed, and a linear regression relationship between logarithm of NH3 flux and lagoon surface temperature (T1) was obtained. Correlations between lagoon NH3 flux and chemical parameters, such as pH, total Kjeldahl nitrogen (TKN), and total ammoniacal nitrogen (TAN) were found to be statistically insignificant or weak. In addition to lagoon surface temperature, the difference (D) between air temperature and the lagoon surface temperature was also found to influence the NH3 flux, especially when D > 0 (i.e., air hotter than lagoon). This hot-air effect is included in the statistical-observational model obtained in this study, which was used further in the companion study (Part II), to compare the emissions from potential environmental superior technologies to evaluate the effectiveness of each technology.     

Correction to: Water‑induced erosion potentiality and vulnerability assessment in Kangsabati river basin,eastern India

Environment, Development and Sustainability -