Effect of nanoclay on thermal behavior of jute reinforced composite

Due to enhanced mechanical strength, superior flame resistance, and decreased gas permeability, montmorillonite nanoclay has been introduced to the jute-polyester resin composite materials for structural application. Long-fiber Bangla tossa special jute is being used as reinforcement materials along with 1, 3, and 5% addition of nanoclay within the matrix-fiber mixture to find the optimum percentage of nanoclay. These doped hand lay-up-processed plates are used to made samples for dynamic mechanical analysis and thermogravimetry testing as per ASTM standards. Temperature-induced weight loss due to thermal decomposition was measured and char residue was calculated up to 1000 °C, where 5% added nanoclay samples showed better thermal stability. Viscoelastic properties through storage modulus and loss modulus showed better stability with 1% nanoclay-added composite in dynamic mechanical analysis.Moisture and temperature did not affect the tested samples significantly in diminutive exposure for 1% nanoclay-added samples even though there is a loss of storage modulus 12 to 30% for 3 and 5% nanoclay-added samples, respectively

Temperature effect and battery charging characteristics analysis based on charging C-rate

Developing fast charging proprieties for LiFePo4 battery is a key issue for a wider deployment of EV. The main drawback of LiFePo4 battery charging is overcharge, overcurrent and high temperature which affects longevity, efficiency, and battery life cycle. In this research, lithium iron phosphate (LiFePo4) battery is investigated for fast, and rapid charging with CC-CV principle. MATLAB/Simulink based custom-designed tool was developed. A dynamic model of lithium-ion phosphate battery is proposed in this research by considering the significant temperature and capacity fading effects. Results have shown that the LiFePo4 battery can be used for fast charging up to 100% and rapid charging up to 85% by maintaining the condition for lifespan of the battery and to shorten the charging time. The simulation results have been showed that, the constructed model can really represent the dynamic performance feature of the lithium-ion battery. The modified model can assess the efficiency of battery execution based on charging C-rate conditions. © BEIESP

HydroDS: Data Services in Support of Physically Based, Distributed Hydrological Models

Physically based distributed hydrologic models require geospatial and time-series data that take considerable time and effort in processing them into model inputs. Tools that automate and speed up input processing facilitate the application of these models. In this study, we developed a set of web-based data services called HydroDS to provide hydrologic data processing ‘software as a service.’ HydroDS provides functions for processing watershed, terrain, canopy, climate, and soil data. The services are accessed through a Python client library that facilitates developing simple but effective data processing workflows with Python. Evaluations of HydroDS by setting up the Utah Energy Balance and TOPNET models for multiple headwater watersheds in the Colorado River basin show that HydroDS reduces the input preparation time compared to manual processing. It also removes the requirements for software installation and maintenance by the user, and the Python workflows enhance reproducibility of hydrologic data processing and tracking of provenance

Antioxidant Potential and Brine Shrimp Lethality bioassay of Spilanthes acmella Flower Extract

The current research study has been carried out to explore the antioxidant activity and brine shrimp lethality bioassay of different fractions from the flower extract of Spilanthes acmella. Besides, this experiment was also assessed to find out the proximate analysis and phytochemical screening by following the perfect protocol. To fractionate by soxhletion using sequential extraction techniques powdered flower of the plant were treated with different solvents including n-hexane, chloroform, ethanol and water. For the evaluation of antioxidant activity, total antioxidant capacity determination, determination of total phenolic content and total Flvonoids contents by aluminium tricholoride method were used. In addition, ascorbic acid and gallic acid was used as a standard antioxidant compound in these studies. Concerning the proximate analysis, moisture content, total ash value, acid insoluble ash and water soluble ash value were found 8.6%, 3.76%, 3.30%, 3.20% respectively. To evaluate cytotoxicity, the brine shrimp lethality bioassay was used. For phytochemical screening different extract of those solvents were utilized that disclosed the presence of alkaloids, flavonoids, phenolic compounds, Tannins, amino acids on different fractions but the absence of reducing sugar and saponins. The results of all assay showed that all the extracts of Spilanthes acmella flower possess significant antioxidant activity. In brine shrimp lethality bioassay, ethanol extract of flower effect to brine shrimp nauplii and exhibiting highest toxicity having LC50 value 1.20 μg/ml as compared to standard dimethyl sulfoxide (LC50 1.31 µg/ml). These evaluations suggest that Spilanthes acmella flowers might be a better source of antioxidants and possess important cytotoxic effect

Structural applications and emerging trends of nano- and biocomposites: a review

Composite materials are currently being used in applications for aerospace, leisure, construction, sport, packaging and automotive industries, especially for the last mentioned application.Yet, present day trends such as a rise in interest in environmentally-friendly materials and the advancement of nanotechnology has led to the emergence of nano- and biocomposites. These materials offer comparable mechanical properties to conventional composites, with biocomposites having the added benefit of being biodegradable. This paper explores the nano- and biocomposites, focussing additionally on structural applications and emerging trends of this growing market

Mechanical performance of montmorillonite dispersed jute reinforced composite

Surface treated jute accomplished by chemical treatments which enhanced the adhesion between polyester resin and modified surface within the composite. Baking time for 6 hours also reduced the moisture content and diminishes the hydrophilic properties of the corchorus olitorius jute fiber. Montmorillonite shell type nanoclay was dispersed 1%, 3% and 5% within the jute fiber polyester matrix to enhance the mechanical performance. Effect of temperature and high humidity were evaluated for this nanoclay filled composite through hydrothermal test for 15 days in the environmental chamber. Environmental degradation was not remarkable due to the exposure of the temperature 80ᴼC and 95% RH for this time period. Ductile properties like yield strength (YS), % of elongation were calculated for two different stoke rate to understand the strain rate effect. 1% addition of nanoclay within the composite shows the better performance in terms of yield, flexural and impact strength while 5% dispersed of nanoclay does not have any beneficial effect within the composite due to the density and non-homogeneous mixture of the clay. Fracture morphology by SEM/ FESEM revealed voids, broken fibers and nano particles within the matrix

Prediction of crack growth propagation of a super alloy through ANN modeling

Linear-elastic fracture mechanics based technique was used to measure the fracture toughness in terms of K1C of a solid solution super alloy. Due to thermal fatigue and high temperature exposure for various application of Alloy 617, it was demanded to measure crack growth behaviour of this alloy. Pre-cracked compact tension (CT) specimens ware used to determine the crack growth rate (CGR) of alloy 617 by direct current potential drop (DCPD) in-situ crack monitoring technique. Artificial Neural network (ANN) statistical model computed different fracture parameters from experimental inputs by feeding information to the network. This feed-forward network calculated the threshold fracture toughness, number of cycle to failure, slope of the Paris curve for the alloy at different temperatures and load ratios. The computational model correlates and converges with the experimental results with a maximum deviation of 6%. Thus, the model is recommended for complex and stochastic application of the nickel base super alloy 617

Physically Based Modeling of the Impacts of Climate Change on Streamflow Regime

Understanding the implications of climate change on streamflow regime is complex as changes in climate vary over space and time. However, a better understanding of the impact of climate change is required for identifying how stream ecosystems vulnerable to these changes, and ultimately to guide the development of robust strategies for reducing risk in the face of changing climatic conditions. Here I used physically based hydrologic modeling to improve understanding of how climate change may impact streamflow regimes and advance some of the cyberinfrastructure and GIS methodologies that support physically based hydrologic modeling by: (1) using a physically based model to examine the potential effects of climate change on ecologically relevant aspects of streamflow regime, (2) developing data services in support of input data preparation for physically based distributed hydrologic models, and (3) enhancing terrain analysis algorithms to support rapid watershed delineation over large area. TOPNET, a physically based hydrologic model was applied over eight watersheds across the U.S to assess the sensitivity and changes of the streamflow regime due to climate change. Distributed hydrologic models require diverse geospatial and time series inputs, the acquisition and preparation of which are labor intensive and difficult to reproduce. I developed web services to automate the input data preparation steps for a physically based distributed hydrological model to enable water scientist to spend less time processing input data. This input includes terrain analysis and watershed delineation over a large area. However, limitations of current terrain analysis tools are (1) some support only a limited set of specific raster and vector data formats, and (2) all that we know of require data to be in a projected coordinate system. I enhanced terrain analysis algorithms to extend their generality and support rapid, web-based watershed delineation services. Climate change studies help to improve the scientific foundation for conducting climate change impacts assessments, thus building the capacity of the water management community to understand and respond to climate change. Web-based data services and enhancements to terrain analysis algorithms to support rapid watershed delineation will impact a diverse community of researchers involved terrain analysis, hydrologic and environmental modeling

Application of TOPNET model for quantifying stream flow regime variables over different watersheds in US

This paper illustrates the application of TOPNET, a distributed physically based hydrologic model in different watersheds across US to determine streamflow regime variables which are a significant influencing factor for both in and out –of stream environments. The models are being established so as to be able to predict and examined changes in flow regimes due to climate change. This paper discusses the model parameterization and calibration parts of the work. A 30 m DEM obtained from National elevation dataset was used to delineate streams and sub watersheds. TauDEM (Tarboton 2002) software was used for delineating stream networks and obtaining slope and catchment area. For this application, the TOPNET model used daily precipitation and temperature data from Daymet, which has fine spatial (1km x1km) and temporal resolution (daily). Initial model parameters for each subbasin were estimated from SSURGO soil and National Land Cover (NLCD) data. USGS streamflow data was used as observed for model calibration. The calibration used a multiplier for each parameter which was estimated using a controlled elitist multi objective genetic algorithm. Automation of all input data preparation workflows and calibration of the model make implementation of TOPNET over those watersheds efficient. Visual comparison of time series plots and statistical measures namely, Nash-Sutcliffe efficiency (NS), percent bias (PBIAS) and root mean square error (RMSE) were used to evaluate the model performance. For most of the watersheds, the model performed relatively well and gave a good representation of the flow hydrographs of the watersheds. Stream flow regime variables derived from calibrated flow were nicely comparable to those from observed flow. The promising simulation results obtained in this study reveal the usefulness of the TOPNET model for estimating streamflow regime variables