Search results for: droplets and particle concentrations

Authors: Ankit Kumar Yadav, Nagendra R. Velaga

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Driving under the influence of alcohol impairs the driving performance and increases the crash risks worldwide. The present study investigated the effect of different Blood Alcohol Concentrations (BAC) on the accelerating and braking behaviour of drivers with the help of driving simulator experiments. Eighty-two licensed Indian drivers drove on the rural road environment designed in the driving simulator at BAC levels of 0.00%, 0.03%, 0.05%, and 0.08% respectively. Driving performance was analysed with the help of vehicle control performance indicators such as mean acceleration and mean brake pedal force of the participants. Preliminary analysis reported an increase in mean acceleration and mean brake pedal force with increasing BAC levels. Generalized linear mixed models were developed to quantify the effect of different alcohol levels and explanatory variables such as driver’s age, gender and other driver characteristic variables on the driving performance indicators. Alcohol use was reported as a significant factor affecting the accelerating and braking performance of the drivers. The acceleration model results indicated that mean acceleration of the drivers increased by 0.013 m/s², 0.026 m/s² and 0.027 m/s² for the BAC levels of 0.03%, 0.05% and 0.08% respectively. Results of the brake pedal force model reported that mean brake pedal force of the drivers increased by 1.09 N, 1.32 N and 1.44 N for the BAC levels of 0.03%, 0.05% and 0.08% respectively. Age was a significant factor in both the models where one year increase in drivers’ age resulted in 0.2% reduction in mean acceleration and 19% reduction in mean brake pedal force of the drivers. It shows that driving experience could compensate for the negative effects of alcohol to some extent while driving. Female drivers were found to accelerate slower and brake harder as compared to the male drivers which confirmed that female drivers are more conscious about their safety while driving. It was observed that drivers who were regular exercisers had better control on their accelerator pedal as compared to the non-regular exercisers during drunken driving. The findings of the present study revealed that drivers tend to be more aggressive and impulsive under the influence of alcohol which deteriorates their driving performance. Drunk driving state can be differentiated from sober driving state by observing the accelerating and braking behaviour of the drivers. The conclusions may provide reference in making countermeasures against drinking and driving and contribute to traffic safety.

Keywords: alcohol, acceleration, braking behaviour, driving simulator

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Authors: Jin-Hyeong Park, Hong-Seok Kim, Jin-Hyeok Yim, Young-Ji Kim, Dong-Hyeon Kim, Jung-Whan Chon, Kun-Ho Seo

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Salmonella contamination in chicken samples can cause major health problems in humans. However, not only the effects of antibiotic treatment during growth but also the impacts of poultry slaughter line on the prevalence of Salmonella in final chicken meat sold to consumers are unknown. In this study, we compared the isolation rates and antimicrobial resistance of Salmonella between antibiotic-free, conventional, conventional Korean native retail chicken meat samples and clonal divergence of Salmonella isolates by multilocus sequence typing. In addition, the distribution of extended-spectrum β-lactamase (ESBL) genes in ESBL-producing Salmonella isolates was analyzed. A total of 72 retail chicken meat samples (n = 24 antibiotic-free broiler [AFB] chickens, n = 24 conventional broiler [CB] chickens, and n = 24 conventional Korean native [CK] chickens) were collected from local retail markets in Seoul, South Korea. The isolation rates of Salmonella were 66.6% in AFB chickens, 45.8% in CB chickens, and 25% in CK chickens. By analyzing the minimum inhibitory concentrations of β -lactam antibiotics with the disc-diffusion test, we found that 81.2% of Salmonella isolates from AFB chickens, 63.6% of isolates from CB chickens, and 50% of isolates from CK chickens were ESBL producers; all ESBL-positive isolates had the CTX-M-15 genotype. Interestingly, all ESBL-producing Salmonella were revealed as ST16 by multilocus sequence typing. In addition, all CTX-M-15-positive isolates had the genetic platform of blaCTX-M gene (IS26-ISEcp1-blaCTX-M-15-IS903), to the best of our knowledge, this is the first report in Salmonella around the world. The Salmonella ST33 strain (S. Hadar) isolated in this study has never been reported in South Korea. In conclusion, our findings showed that antibiotic-free retail chicken meat products were also largely contaminated with ESBL-producing Salmonella and that their ESBL genes and genetic platforms were the same as those isolated from conventional retail chicken meat products.

Keywords: antibiotic-free poultry, conventional poultry, multilocus sequence typing, extended-spectrum β-lactamase, antimicrobial resistance

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Authors: Rupas Kumar M., Saravana Kumar M., Amarendra Kumar S., Likhita Komal V., Sree Deepthi M.

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The demand for water is increasing at an alarming rate due to rapid urbanization and increase in population. Due to freshwater scarcity, Groundwater became the necessary source of potable water to major parts of the world. This problem of freshwater scarcity and groundwater dependency is very severe particularly in developing countries and overpopulated regions like India. The present study aimed at evaluating the Ground Water Quality Index (GWQI), which represents overall quality of water at certain location and time based on water quality parameters. To evaluate the GWQI, sixteen water quality parameters have been considered viz. colour, pH, electrical conductivity, total dissolved solids, turbidity, total hardness, alkalinity, calcium, magnesium, sodium, chloride, nitrate, sulphate, iron, manganese and fluorides. The groundwater samples are collected from Kadapa City in Andhra Pradesh, India and subjected to comprehensive physicochemical analysis. The high value of GWQI has been found to be mainly from higher values of total dissolved solids, electrical conductivity, turbidity, alkalinity, hardness, and fluorides. in the present study, citrus limetta (sweet lemon) peel powder has used as a coagulant and GWQI values are recorded in different concentrations to improve GWQI. Sensitivity analysis is also carried out to determine the effect of coagulant dosage, mixing speed and stirring time on GWQI. The research found the maximum percentage improvement in GWQI values are obtained when the coagulant dosage is 100ppm, mixing speed is 100 rpm and stirring time is 10 mins. Alum is also used as a coagulant aid and the optimal ratio of citrus limetta and alum is identified as 3:2 which resulted in best GWQI value. The present study proposes Citrus limetta peel powder as a potential natural coagulant to treat Groundwater and to improve GWQI.

Keywords: alum, Citrus limetta, ground water quality index, physicochemical analysis

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Authors: A. Durgadevi, S. Pushpavanam

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For the past several decades, CO2 levels have been dramatically increasing in the atmosphere due to the man-made emissions such as fossil fuel-fired power plants. With the increase in CO2 emissions, CO2 concentration in the atmosphere has increased resulting in global warming. This shows the need to study different ways to capture the emitted CO2 directly from the exhausts of power plants or atmosphere. There are several ways to remove CO2, such as absorption into a liquid solvent, adsorption into a solid, cryogenic separation, permeation through membranes and photochemical conversion. In most industries, the absorption of CO2 in chemical solvents (in absorption towers) is used for CO2 capture. In these towers, the mass transfer along with chemical reactions take place between the gas and liquid phase. This helps in the separation of CO2 from other gases. It is important to understand these processes in detail. These flow patterns are difficult to maintain in large scale industrial absorbers. So to get accurate information controlled gas-liquid absorption experiments are carried out in milli-channels in this work under controlled atmosphere. The absorption experiments of CO2 in varying concentrations of sodium hydroxide solution are carried out in T-junction glass milli-channels with a circular cross section (inner diameter of 2mm). The gas and liquid flow rates are controlled by a mass flow controller (MFC) and a Harvard syringe pump respectively. The slug flow in the channel is recorded using a camera and the videos are analysed. The gas slug of pure CO2 is found to decrease in size along the length of the channel due to absorption of gas in the liquid. This is also captured with the model developed and the mass transfer characteristics are studied. The pressure drop across the channel is determined by sum of the pressure drops from the gas slugs and the liquid plugs. A dimensionless correlation for the mass transfer coefficient is developed in terms of Sherwood number and compared with the existing correlations in the literature. They are found to be in close agreement with each other. In this case, due to the presence of chemical reaction, the enhancement of mass transfer is obtained. This is quantified with the help of an enhancement factor.

Keywords: absorption, enhancement factor, mass transfer coefficient, Sherwood number

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Authors: Jaeyoung Kim, Heeju Lee, Huijin Jung, Heesoo Pyo, Seungki Kim, Joonseok Lee

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Avian influenza viruses (AIV) are the primary cause of highly contagious respiratory diseases caused by type A influenza viruses of the Orthomyxoviridae family. AIV are categorized on the basis of types of surface glycoproteins such as hemagglutinin and neuraminidase. Certain H5 and H7 subtypes of AIV have evolved to the high pathogenic avian influenza (HPAI) virus, which has caused considerable economic loss to the poultry industry and led to severe public health crisis. Several commercial kits have been developed for on-site detection of AIV. However, the sensitivity of these methods is too low to detect low virus concentrations in clinical samples and opaque stool samples. Here, we introduced a background-free near-infrared (NIR)-to-NIR upconversion nanoparticle-based lateral flow immunoassay (NNLFA) platform to yield a sensor that detects AIV within 20 minutes. Ca²⁺ ion in the shell was used to enhance the NIR-to-NIR upconversion photoluminescence (PL) emission as a heterogeneous dopant without inducing significant changes in the morphology and size of the UCNPs. In a mixture of opaque stool samples and gold nanoparticles (GNPs), which are components of commercial AIV LFA, the background signal of the stool samples mask the absorption peak of GNPs. However, UCNPs dispersed in the stool samples still show strong emission centered at 800 nm when excited at 980 nm, which enables the NNLFA platform to detect 10-times lower viral load than a commercial GNP-based AIV LFA. The detection limit of NNLFA for low pathogenic avian influenza (LPAI) H5N2 and HPAI H5N6 viruses was 10² EID₅₀/mL and 10³.⁵ EID₅₀/mL, respectively. Moreover, when opaque brown-colored samples were used as the target analytes, strong NIR emission signal from the test line in NNLFA confirmed the presence of AIV, whereas commercial AIV LFA detected AIV with difficulty. Therefore, we propose that this rapid and background-free NNLFA platform has the potential of detecting AIV in the field, which could effectively prevent the spread of these viruses at an early stage.

Keywords: avian influenza viruses, lateral flow immunoassay on-site detection, upconversion nanoparticles

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Authors: Ilze Dimanta, Zane Rutkovska, Vizma Nikolajeva, Janis Kleperis, Indrikis Muiznieks

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Majority of word’s steadily increasing energy consumption is provided by non-renewable fossil resources. Need to find an alternative energy resource is essential for further socio-economic development. Hydrogen is renewable, clean energy carrier with high energy density (142 MJ/kg, accordingly – oil has 42 MJ/kg). Biological hydrogen production is an alternative way to produce hydrogen from renewable resources, e.g. using organic waste material resource fermentation that facilitate recycling of sewage and are environmentally benign. Hydrogen gas is produced during the fermentation process of bacteria in anaerobic conditions. Bacteria are producing hydrogen in the liquid phase and when thermodynamic equilibrium is reached, hydrogen is diffusing from liquid to gaseous phase. Because of large quantities of available crude glycerol and the highly reduced nature of carbon in glycerol per se, microbial conversion of it seems to be economically and environmentally viable possibility. Such industrial organic waste product as crude glycerol is perspective for usage in feedstock for hydrogen producing bacteria. The process of biodiesel production results in 41% (w/w) of crude glycerol. The developed lab-scale test system (experimental bioreactor) with hydrogen micro-electrode (Unisense, Denmark) was used to determine hydrogen production yield and rate in the liquid phase. For hydrogen analysis in the gas phase the RGAPro-100 mass-spectrometer connected to the experimental test-system was used. Fermentative bacteria strains were tested for hydrogen gas production rates. The presence of hydrogen in gaseous phase was measured using mass spectrometer but registered concentrations were comparatively small. To decrease the hydrogen partial pressure in liquid phase reactor with a system for continuous bubbling with inert gas was developed. H2 production rate for the best producer in liquid phase reached 0,40 mmol H2/l, in gaseous phase - 1,32 mmol H2/l. Hydrogen production rate is time dependent – higher rate of hydrogen production is at the fermentation process beginning when concentration increases, but after three hours of fermentation, it decreases.

Keywords: bio-hydrogen, fermentation, experimental bioreactor, crude glycerol

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Authors: Selim M. Khan

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Indoor air quality is strongly influenced by the presence of radioactive radon (222Rn) gas. Indeed, exposure to high 222Rn concentrations is unequivocally linked to DNA damage and lung cancer and is a worsening issue in North American and European built environments, having increased over time within newer housing stocks as a function of as yet unclear variables. Indoor air radon concentration can be influenced by a wide range of environmental, structural, and behavioral factors. As some of these factors are quantitative while others are qualitative, no single statistical model can determine indoor radon level precisely while simultaneously considering all these variables across a complex and highly diverse dataset. The ability of AI- machine (deep) learning to simultaneously analyze multiple quantitative and qualitative features makes it suitable to predict radon with a high degree of precision. Using Canadian and Swedish long-term indoor air radon exposure data, we are using artificial deep neural network models with random weights and polynomial statistical models in MATLAB to assess and predict radon health risk to human as a function of geospatial, human behavioral, and built environmental metrics. Our initial artificial neural network with random weights model run by sigmoid activation tested different combinations of variables and showed the highest prediction accuracy (>96%) within the reasonable iterations. Here, we present details of these emerging methods and discuss strengths and weaknesses compared to the traditional artificial neural network and statistical methods commonly used to predict indoor air quality in different countries. We propose an artificial deep neural network with random weights as a highly effective method for assessing and predicting indoor radon.

Keywords: radon, radiation protection, lung cancer, aI-machine deep learnng, risk assessment, risk prediction, Europe, North America

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Authors: Volker Landersheim, Daria Manushyna, Thinh Pham, Dai-Duong Tran, Thomas Geury, Omar Hegazy, Steven Wilkins

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Air pollution is one of the emerging problems in our society. Targets of reduction of CO₂ emissions address low-carbon and resource-efficient transport. (Plug-in) hybrid electric propulsion concepts offer the possibility to reduce total cost of ownership (TCO) and emissions for public transport vehicles (e.g., bus application). In this context, typically, diesel engines are used to form the hybrid propulsion system of the vehicle. Though the technological development of diesel engines experience major advantages, some challenges such as the high amount of particle emissions remain relevant. Gaseous fuels (i.e., compressed natural gases (CNGs) or liquefied petroleum gases (LPGs) represent an attractive alternative to diesel because of their composition. In the framework of the research project 'Optimised Real-world Cost-Competitive Modular Hybrid Architecture' (ORCA), which was funded by the EU, two different hybrid-electric propulsion concepts have been investigated: one using a diesel engine as internal combustion engine and one using CNG as fuel. The aim of the current study is to analyze specific benefits for the aforementioned hybrid propulsion systems for predefined driving scenarios with regard to emissions and total cost of ownership in bus application. Engine models based on experimental data for diesel and CNG were developed. For the purpose of designing optimal energy management strategies for each propulsion system, maps-driven or quasi-static models for specific engine types are used in the simulation framework. An analogous modelling approach has been chosen to represent emissions. This paper compares the two concepts regarding their CO₂ and NOx emissions. This comparison is performed for relevant bus missions (urban, suburban, with and without zero-emission zone) and with different energy management strategies. In addition to the emissions, also the downsizing potential of the combustion engine has been analysed to minimize the powertrain TCO (pTCO) for plug-in hybrid electric buses. The results of the performed analyses show that the hybrid vehicle concept using the CNG engine shows advantages both with respect to emissions as well as to pTCO. The pTCO is 10% lower, CO₂ emissions are 13% lower, and the NOx emissions are more than 50% lower than with the diesel combustion engine. These results are consistent across all usage profiles under investigation.

Keywords: bus transport, emissions, hybrid propulsion, pTCO, CNG

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Authors: Venkateswara R. Naira, Debasish Das, Soumen K. Maiti

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Achieving high cell densities of microalgae under obligatory light-limiting and high light conditions of diurnal (low-high-low variations of daylight intensity) sunlight are further limited by CO₂ supply and dissolved oxygen (DO) accumulation in large-scale photobioreactors. High DO levels cause low growth due to photoinhibition and/or photorespiration. Hence, scalable elevated CO₂ levels (% in air) and their effect on DO accumulation in a 10 L cylindrical membrane photobioreactor (a vertical tubular type) are studied in the present study. The CO₂ elevation strategies; biomass-based, pH control based (types II & I) and diurnal light based, were explored to study the growth of Chlorella sp. FC2 IITG under single-sided LED lighting in the laboratory, mimicking diurnal sunlight. All the experiments were conducted in fed-batch mode by maintaining N and P sources at least 50% of initial concentrations of the optimized BG-11 medium. It was observed that biomass-based (2% - 1st day, 2.5% - 2nd day and 3% - thereafter) and well-known pH control based, type-I (5.8 pH throughout) strategies were found lethal for FC2 growth. In both strategies, the highest peak DO accumulation of 150% air saturation was resulted due to high photosynthetic activity caused by higher CO₂ levels. In the pH control based type-I strategy, automatically resulted CO₂ levels for pH control were recorded so high (beyond the inhibition range, 5%). However, pH control based type-II strategy (5.8 – 2 days, 6.3 – 3 days, 6.7 – thereafter) showed final biomass titer up to 4.45 ± 0.05 g L⁻¹ with peak DO of 122% air saturation; high CO₂ levels beyond 5% (in air) were recorded thereafter. Thus, it became sustainable for obtaining high biomass. Finally, a diurnal light based (2% - low light, 2.5 % - medium light and 3% - high light) strategy was applied on the basis of increasing/decreasing photosynthesis due to increase/decrease in diurnal light intensity. It has resulted in maximum final biomass titer of 5.33 ± 0.12 g L⁻¹, with total biomass productivity of 0.59 ± 0.01 g L⁻¹ day⁻¹. The values are remarkably higher than constant 2% CO₂ level (final biomass titer: 4.26 ± 0.09 g L⁻¹; biomass productivity: 0.27 ± 0.005 g L⁻¹ day⁻¹). However, 135% air saturation of peak DO was observed. Thus, the diurnal light based elevation should be further improved by using CO₂ enriched N₂ instead of air. To the best of knowledge, the light-based CO₂ elevation strategy is not reported elsewhere.

Keywords: Chlorella sp., CO₂ elevation strategy, dissolved oxygen accumulation, diurnal light based CO₂ elevation, high cell density, microalgae, scale-up

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Authors: Tooba Aslam, Efthalia Chatzisymeon

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UV-assisted irradiation technologies are well-established for water and wastewater treatment. UVC treatments are widely used at large-scale, while UVA irradiation has more often been applied in combination with a catalyst (e.g. TiO₂ or FeSO₄) in smaller-scale systems. A technical issue of these systems is the formation of fouling on the quartz sleeves that houses the lamps. This fouling can prevent complete irradiation, therefore reducing the efficiency of the process. This paper investigates the effects of operational parameters, such as the type of wastewater, irradiation source, H₂O₂ addition, and water pH on fouling formation and, ultimately, the treatment of municipal wastewater. Batch experiments have been performed at lab-scale while monitoring water quality parameters including: COD, TS, TSS, TDS, temperature, pH, hardness, alkalinity, turbidity, TOC, UV transmission, UV₂₅₄ absorbance, and metal concentrations. The residence time of the wastewater in the reactor was 5 days in order to observe any fouling formation on the quartz surface. Over this period, it was observed that chemical oxygen demand (COD) decreased by 30% and 59% during photolysis (Ultraviolet A) and photo-catalysis (UVA/Fe/H₂O₂), respectively. Higher fouling formation was observed with iron-rich and phosphorous-rich wastewater. The highest rate of fouling was developed with phosphorous-rich wastewater, followed by the iron-rich wastewater. Photo-catalysis (UVA/Fe/H₂O₂) had better removal efficiency than photolysis (UVA). This was attributed to the Photo-Fenton reaction, which was initiated under these operational conditions. Scanning electron microscope (SEM) measurements of fouling formed on the quartz sleeves showed that particles vary in size, shape, and structure; some have more distinct structures and are generally larger and have less compact structure than the others. Energy-dispersive X-ray spectroscopy (EDX) results showed that the major metals present in the fouling cake were iron, phosphorous, and calcium. In conclusion, iron-rich wastewaters are more suitable for UV-assisted treatment since fouling formation on quartz sleeves can be minimized by the formation of oxidizing agents during treatment, such as hydroxyl radicals.

Keywords: advanced oxidation processes, photo-fenton treatment, photo-catalysis, wastewater treatment

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Authors: Retang A. Mokua, Julia Glenday, Jacobus M. Nel

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Understanding hydrological processes in mountain headwater catchments, such as the Jonkershoek Valley, is crucial for improving the predictive capability of hydrologic modeling in the Cape Fold Mountain region of South Africa, incorporating the influence of the Table Mountain Group fractured rock aquifers. Determining the contributions of various possible surface and subsurface flow pathways in such catchments has been a challenge due to the complex nature of the fractured rock geology, low ionic concentrations, high rainfall, and streamflow variability. The study aimed to describe the mechanisms of streamflow generation during two seasons (dry and wet). In this study, stable isotopes of water (18O and 2H), hydrochemical tracer electrical conductivity (EC), hydrometric data were used to assess the spatial and temporal variation in flow pathways and geographic sources of stream water. Stream water, groundwater, two shallow piezometers, and spring samples were routinely sampled at two adjacent headwater sub-catchments and analyzed for isotopic ratios during baseflow conditions between January 2018 and January 2019. From these results, no significance (p > 0.05) in seasonal variations in isotopic ratios were observed, the stream isotope signatures were consistent throughout the study period. However, significant seasonal and spatial variations in the EC were evident (p < 0.05). The findings suggest that, in the dry season, baseflow generation mechanisms driven by groundwater and interflow as discharge from perennial springs in these catchments are the primary contributors. The wet season flows were attributed to interflow and perennial and ephemeral springs. Furthermore, the observed seasonal variations in EC were indicative of a greater proportion of sub-surface water inputs. With these results, a conceptual model of streamflow generation processes for the two seasons was constructed.

Keywords: electrical conductivity, Jonkershoek valley, stable isotopes, table mountain group

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Authors: Sangho Park, Mansoo Kim, Kyujung Chae, Junhyuk Yang

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The International Maritime Organization (IMO) recognized the problem of invasive species invasion and adopted the "International Convention for the Control and Management of Ships' Ballast Water and Sediments" in 2004, which came into force on September 8, 2017. In 2011, the IMO approved the "Guidelines for the Control and Management of Ships' Biofouling to Minimize the Transfer of Invasive Aquatic Species" to minimize the movement of invasive species by hull-attached organisms and required ships to manage the organisms attached to their hulls. Invasive species enter new environments through ships' ballast water and hull attachment. However, several obstacles to implementing these guidelines have been identified, including a lack of underwater cleaning equipment, regulations on underwater cleaning activities in ports, and difficulty accessing crevices in underwater areas. The shipping industry, which is the party responsible for understanding these guidelines, wants to implement them for fuel cost savings resulting from the removal of organisms attached to the hull, but they anticipate significant difficulties in implementing the guidelines due to the obstacles mentioned above. Robots or people remove the organisms attached to the hull underwater, and the resulting wastewater includes various species of organisms and particles of paint and other pollutants. Currently, there is no technology available to sterilize the organisms in the wastewater or stabilize the heavy metals in the paint particles. In this study, we aim to analyze the characteristics of the wastewater generated from the removal of hull-attached organisms and select the optimal treatment technology. The organisms in the wastewater generated from the removal of the attached organisms meet the biological treatment standard (D-2) using the sterilization technology applied in the ships' ballast water treatment system. The heavy metals and other pollutants in the paint particles generated during removal are treated using stabilization technologies such as thermal decomposition. The wastewater generated is treated using a two-step process: 1) development of sterilization technology through pretreatment filtration equipment and electrolytic sterilization treatment and 2) development of technology for removing particle pollutants such as heavy metals and dissolved inorganic substances. Through this study, we will develop a biological removal technology and an environmentally friendly processing system for the waste generated after removal that meets the requirements of the government and the shipping industry and lays the groundwork for future treatment standards.

Keywords: biofouling, ballast water treatment system, filtration, sterilization, wastewater

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Authors: Sospeter P. Maganga, Alphonce Wikedzi, Mussa D. Budeba, Samwel V. Manyele

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This study characterizes complex gold ores (elemental and mineralogical composition, gold distribution, ore grindability, and mineral liberation) for preliminary process selection. About 200 kg of ore samples were collected from each location using systematic sampling by mass interval. Ores were dried, crushed, milled, and split into representative sub-samples (about 1 kg) for elemental and mineralogical composition analyses using X-ray fluorescence (XRF), fire assay finished with Atomic Absorption Spectrometer (AAS), and X-ray Diffraction (XRD) methods, respectively. The gold distribution was studied on size-by-size fractions, while ore grindability was determined using the standard Bond test. The mineral liberation analysis was conducted using ThermoFisher Scientific Mineral Liberation Analyzer (MLA) 650, where unsieved polished grain mounts (80% passing 700 µm) were used as MLA feed. Two MLA measurement modes, X-ray modal analysis (XMOD) and sparse phase liberation-grain X-ray mapping analysis (SPL-GXMAP), were employed. At least two cyanide consumers (Cu, Fe, Pb, and Zn) and kinetics impeders (Mn, S, As, and Bi) were present in all locations investigated. Copper content at Kapanda (0.77% Cu) and Ibindi (7.48% Cu) exceeded the recommended threshold of 0.5% Cu for direct cyanidation. The gold ore at Ibindi indicated a higher rate of grinding compared to other locations. This could be explained by the highest grindability (2.119 g/rev.) and lowest Bond work index (10.213 kWh/t) values. The pyrite-marcasite, chalcopyrite, galena, and siderite were identified as major gold, copper, lead, and iron-bearing minerals, respectively, with potential for economic extraction. However, only gold and copper can be recovered under conventional milling because of grain size issues (galena is exposed by 10%) and process complexity (difficult to concentrate and smelt iron from siderite). Therefore, the preliminary process selection is copper flotation followed by gold cyanidation for Kapanda and Ibindi ores, whereas gold cyanidation with additives such as glycine or ammonia is selected for Mawemeru and Itumbi ores because of low concentrations of Cu, Pb, Fe, and Zn minerals.

Keywords: complex gold ores, mineral liberation, ore characterization, ore grindability

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Authors: Shih-Ping Liu, Cheng-Hsuan Chang, Yu-Chuen Huang, Shih-Yin Chen, Woei-Cherng Shyu

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Embryonic stem cells (ES) and induced pluripotnet stem cells (iPS) are both pluripotent stem cells. For mouse stem cells culture technology, leukemia inhibitory factor (LIF) was used to maintain the pluripotency of stem cells in vitro. However, LIF is an expensive reagent. The goal of this study was to find out a pure compound extracted from Chinese herbal medicine that could maintain stem cells pluripotency to replace LIF and improve the iPS generation efficiency. From 20 candidates traditional Chinese medicine we found that Cordycepsmilitaris triggered the up-regulation of stem cells activating genes (Oct4 and Sox2) expression levels in MEF cells. Cordycepin, a major active component of Cordycepsmilitaris, also could up-regulate Oct4 and Sox2 gene expression. Furthermore, we used ES and iPS cells and treated them with different concentrations of Cordycepin (replaced LIF in the culture medium) to test whether it was useful to maintain the pluripotency. The results showed higher expression levels of several stem cells markers in 10 μM Cordycepin-treated ES and iPS cells compared to controls that did not contain LIF, including alkaline phosphatase, SSEA1, and Nanog. Embryonic body formation and differentiation confirmed that 10 μM Cordycepin-containing medium was capable to maintain stem cells pluripotency after four times passages. For mechanism analysis, microarray analysis indicated extracellular matrix and Jak/Stat signaling pathway as the top two deregulated pathways. In ECM pathway, we determined that the integrin αVβ5 expression levels and phosphorylated Src levels increased after Cordycepin treatment. In addition, the phosphorylated Jak2 and phosphorylated Sat3 protein levels were increased after Cordycepin treatment and suppressed with the Jak2 inhibitor, AG490. The expression of cytokines associated with Jak2/Stat3 signaling pathway were also up-regulated by Q-PCR and ELISA assay. Lastly, we used Oct4-GFP MEF cells to test iPS generation efficiency following Cordycepin treatment. We observed that 10 Μm Cordycepin significantly increased the iPS generation efficiency in day 21. In conclusion, we demonstrated Cordycepin could maintain the pluripotency of stem cells through both of ECM and Jak2/Stat3 signaling pathway and improved iPS generation efficiency.

Keywords: cordycepin, iPS cells, Jak2/Stat3 signaling pathway, molecular biology

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Authors: Julia Cristina Bonaldo, Christophe L. Martin, Severine Romero Baivier, Stephane Mazerat

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Alumina refractories are commonly used in steel and foundry industries. These refractories are prepared through a powder metallurgy route. They are a mixture of hard alumina particles and graphite platelets embedded into a soft carbonic matrix (binder). The powder can be cold pressed isostatically or uniaxially, depending on the application. The compact is then fired to obtain the final product. The quality of the product is governed by the microstructure of the composite and by the process parameters. The compaction behavior and the mechanical properties of the fired product depend greatly on the amount of each phase, on their morphology and on the initial microstructure. In order to better understand the link between these parameters and the macroscopic behavior, we use the Discrete Element Method (DEM) to simulate the compaction process and the fracture behavior of the fired composite. These simulations are coupled with well-designed experiments. Four mixes with various amounts of Al₂O₃ and binder were tested both experimentally and numerically. In DEM, each particle is modelled and the interactions between particles are taken into account through appropriate contact or bonding laws. Here, we model a bimodal mixture of large Al₂O₃ and small Al₂O₃ covered with a soft binder. This composite is itself mixed with graphite platelets. X-ray tomography images are used to analyze the morphologies of the different components. Large Al₂O₃ particles and graphite platelets are modelled in DEM as sets of particles bonded together. The binder is modelled as a soft shell that covers both large and small Al₂O₃ particles. When two particles with binder indent each other, they first interact through this soft shell. Once a critical indentation is reached (towards the end of compaction), hard Al₂O₃ - Al₂O₃ contacts appear. In accordance with experimental data, DEM simulations show that the amount of Al₂O₃ and the amount of binder play a major role for the compaction behavior. The graphite platelets bend and break during the compaction, also contributing to the macroscopic stress. Firing step is modeled in DEM by ascribing bonds to particles which contact each other after compaction. The fracture behavior of the compacted mixture is also simulated and compared with experimental data. Both diametrical tests (Brazilian tests) and triaxial tests are carried out. Again, the link between the amount of Al₂O₃ particles and the fracture behavior is investigated. The methodology described here can be generalized to other particulate materials that are used in the ceramic industry.

Keywords: cold compaction, composites, discrete element method, refractory materials, x-ray tomography

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Authors: Noppadol Poomvises, Prateep Pakdeerod, Anchalee Kongsuk

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In the middle of September 2017, a tropical storm named ‘DOKSURI’ swept through Udon Thani, Northeastern Thailand. The storm dumped heavy rain for many hours and caused large amount of water flowing into Huai Phueng reservoir. Level of impounding water increased rapidly, and the extra water flowed over a service spillway, morning-glory type constructed by concrete material for about 50 years ago. Subsequently, a sinkhole was formed on the dam crest and five points of water piping were found on downstream slope closely to spillway. Three techniques of geophysical investigation were carried out to inspect cause of failures; Electrical Resistivity Imaging (ERI), Multichannel Analysis of Surface Wave (MASW), and Ground Penetrating Radar (GPR), respectively. Result of ERI clearly shows evidence of overtop event and heterogeneity around spillway that implied possibility of previous shape of sinkhole around the pipe. The shear wave velocity of subsurface soil measured by MASW can numerically convert to undrained shear strength of impervious clay core. Result of GPR clearly reveals partial settlements of freeboard zone at top part of the dam and also shaping new refilled material to plug the sinkhole back to the condition it should be. In addition, the GPR image is a main answer to confirm that there are not any sinkholes in the survey lines, only that found on top of the spillway. Integrity interpretation of the three results together with several evidences observed during a field walk-through and data from drilled holes can be interpreted that there are four main causes in this account. The first cause is too much water flowing over the spillway. Second, the water attacking morning glory spillway creates cracks upon concrete contact where the spillway is cross-cut to the center of the dam. Third, high velocity of water inside the concrete pipe sucking fine particle of embankment material down via those cracks and flushing out to the river channel. Lastly, loss of clay material of the dam into the concrete pipe creates the sinkhole at the crest. However, in case of failure by piping, it is possible that they can be formed both by backward erosion (internal erosion along or into embedded structure of spillway walls) and also by excess saturated water of downstream material.

Keywords: dam inspection, GPR, MASW, resistivity

Procedia PDF Downloads 237

Authors: A. Heshmati, M. Y Alikhani, M. T. Godarzi, M. R. Sadeghimanesh

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Herbal essential oil and extracts are a good source of natural antioxidants and antimicrobial compounds. Hypericum is one of the potential sources of these compounds. In this study, the antioxidant and antimicrobial activity of essential oil and aqueous, methanol, ethanol, ethyl acetate and acetone extract of Hypericum scabrum was assessed. Flowers of Hypericum scabrum were collected from the surrounding mountains of Hamadan province and after drying in the shade, the essential oil of the plant was extracted by Clevenger and water, methanol, ethanol, ethyl acetate and acetone extract was obtained by maceration method. Essential oil compounds were identified using the GC-Mass. The Folin-Ciocalteau and aluminum chloride (AlCl₃) colorimetric method was used to measure the amount of phenolic acid and flavonoids, respectively. Antioxidant activity was evaluated using DPPH and FRAP. The minimum inhibitory concentration (MIC) and the minimum bacterial/fungicide concentration (MBC/MFC) of essential oil and extracts were evaluated against Staphylococcus aureus, Bacillus cereus, Pseudomonas aeruginosa, Salmonella typhimurium, Aspergillus flavus and Candida albicans. The essential oil yield of was 0.35%, the lowest and highest extract yield was related to ethyl acetate and water extract. The most component of essential oil was α-Pinene (46.35%). The methanol extracts had the highest phenolic acid (95.65 ± 4.72 µg galic acid equivalent/g dry plant) and flavonoids (25.39 ± 2.73 µg quercetin equivalent/g dry plant). The percentage of DPPH radical inhibition showed positive correlation with concentrations of essential oil or extract. The methanol and ethanol extract had the highest DDPH radical inhibitory. Essential oil and extracts of Hypericum had antimicrobial activity against the microorganisms studied in this research. The MIC and MBC values for essential oils were in the range of 25-25.6 and 25-50 μg/mL, respectively. For the extracts, these values were 1.5625-100 and 3.125-100 μg/mL, respectively. Methanol extracts had the highest antimicrobial activity. Essential oil and extract of Hypericum scabrum, especially methanol extract, have proper antimicrobial and antioxidant activity, and it can be used to control the oxidation and inhibit the growth of pathogenic and spoilage microorganisms. In addition, it can be used as a substitute for synthetic antioxidant and antimicrobial compounds.

Keywords: antimicrobial, antioxidant, extract, hypericum

Procedia PDF Downloads 317

Authors: Soumita Mitra, Santosh Kumar Sarkar

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Hooghly river estuary (HRE), situated at the north eastern part of Bay of Bengal has global significance due to its holiness. It is of immense importance to the local population as it gives perpetual water supply for various activities such as transportation, fishing, boating, bathing etc. to the local people who settled on both the banks of this estuary. This study was done to assess the dissolved and particulate trace metal in the estuary covering a stretch of about 175 Km. The water samples were collected from the surface (0-5 cm) along the salinity gradient and metal concentration were studied both in dissolved and particulate phase using Graphite Furnace Atomic Absorption Spectrophotometer (GF-AAS) along some physical characteristics such as water temperature, salinity, pH, turbidity and total dissolved solids. Although much significant spatial variation was noticed but little enrichment was found along the downstream of the estuary. The mean concentration of the metals in the dissolved and particulate phase followed the same trend and as follows: Fe>Mn>Cr>Zn>Cu>Ni>Pb. The concentration of the metals in the particulate phase were much greater than that in dissolved phase which was also depicted from the values of the partition coefficient (Kd)(ml mg-1). The Kdvalues ranged from 1.5x105 (in case of Pb) to 4.29x106 (in case of Cr). The high value of Kd for Cr denoted that the metal Cr is mostly bounded with the suspended particulate matter while the least value for Pb signified it presence more in dissolved phase. Moreover, the concentrations of all the studied metals in the dissolved phase were many folds higher than their respective permissible limits assested by WHO 2008, 2009 and 2011. On the other hand, according to Sediment Quality Guidelines (SQGs), Zn, Cu and Ni in the particulate phase lied between ERL and ERM values but Cr exceeded ERM values at all the stations confirming that the estuary is mostly contaminated with the particulate Cr and it might cause frequent adverse effects on the aquatic life. Multivariate statistics Cluster analysis was also performed which separated the stations according to the level of contamination from several point and nonpoint sources. Thus, it is found that the estuarine system is much polluted by the toxic metals and further investigation, toxicological studies should be implemented for full risk assessment of this system, better management and restoration of the water quality of this globally significant aquatic system.

Keywords: dissolved and particulate phase, Hooghly river estuary, partition coefficient, surface water, toxic metals

Procedia PDF Downloads 271

Authors: D. H. Tejavathi

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Medicinal plants are globally valuable sources of herbal products. Wild populations of many medicinal plants are facing threat of extinction because of their narrow distribution, endemicity, and degradation of specific habitats. Micropropagation is an established in vitro technique by which large number of clones can be obtained from a small bit of explants in a short span of time within a limited space. Mycorrhization can minimize the transient transplantation shock, experienced by the micropropagated plants when they are transferred from lab to land. AM fungal association improves the physiological status of the host plants through better uptake of water and nutrients, particularly phosphorus. Consequently, the growth performance and biosynthesis of active principles are significantly enhanced in AM fungal treated plants. Bacopa monnieri, Andrographis paniculata, Agave vera-curz, Drymaria cordata and Majorana hortensis, important medicinal plants used in various indigenous systems of medicines, are selected for the present study. They form the main constituents of many herbal formulations. Standard in vitro techniques were followed to obtain the micropropagated plants. Shoot tips and nodal segments were used as explants. Explants were cultured on Murashige and Skoog, and Phillips and Collins media supplemented with various combinations of growth regulators. Multiple shoots were obtained on a media containing both auxins and cytokinins at various concentrations and combinations. Multiple shoots were then transferred to rooting media containing auxins for root induction. Thus, obtained in vitro regenerated plants were subjected to brief acclimatization before transferring them to land. One-month-old in vitro plants were treated with AM fungi, and the symbiotic effect on the overall growth parameters was analyzed. It was found that micropropagation coupled with mycorrhization has significant effect on the enhancement of biomass and biosynthesis of active principles in these selected medicinal plants. In vitro techniques coupled with mycorrhization have opened a possibility of obtaining better clones in respect of enhancement of biomass and biosynthesis of active principles. Beneficial effects of AM fungal association with medicinal plants are discussed.

Keywords: cultivation, medicinal plants, micropropagation, mycorrhization

Procedia PDF Downloads 166

Authors: Kremena Ivanona, Bistra Kunovska, Jana Djunova, Desislava Djunakova, Zdenka Stojanovska

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In recent decades, the general public has become increasingly interested in the impact of air pollutions on their health. Currently, numerous studies are aimed at identifying pollutants in the indoor environment where they carry out daily activities. Internal pollutants can be of both natural and artificial origin. With regard to natural pollutants, special attention is paid to natural radioactivity. In recent years, radon has been one of the most studied indoor pollutants because it has the greatest contribution to human exposure to natural radionuclides. It is a known fact that lung cancer can be caused by radon radiation and it is the second risk factor after smoking for the onset of the disease. The main objective of the study under the National Science Fund of Bulgaria, in the framework of grant No КП-06-Н23/1/07.12.2018 is to evaluate the indoor radon as an important air pollutant in school buildings in order to reduce the exposure to children. The measurements were performed in 48 schools located in 55 buildings in one Bulgarian administrative district (Kardjaly). The nuclear track detectors (CR-39) were used for measurements. The arithmetic and geometric means of radon concentrations are AM = 140 Bq/m3, and GM = 117 Bq/m3 respectively. In 51 school rooms, the radon levels were greater than 200 Bq/m3, and in 28 rooms, located in 17 school buildings, it exceeded the national reference level of 300 Bq/m3, defined in the Bulgarian ordinance on radiation protection (or 30% of the investigated buildings). The statistically significant difference in the values of radon concentration by municipalities (KW, р < 0.001) obtained showed that the most likely reason for the differences between the groups is the geographical location of the buildings and the possible influence of the geological composition. The combined effect of the year of construction (technical condition of the buildings) and the energy efficiency measures was considered. The values of the radon concentration in the buildings where energy efficiency measures have been implemented are higher than those in buildings where they have not been performed. This result confirms the need for investigation of radon levels before conducting the energy efficiency measures in buildings. Corrective measures for reducing the radon levels have been recommended in school buildings with high radon levels in order to decrease the children's exposure.

Keywords: air pollution, indoor radon, children exposure, schools

Procedia PDF Downloads 165

Authors: Chouahda Salima, Soltani Noureddine

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The present study is a part of biological control against mosquitoes. It aims to assess the impact of two xenobiotics (a selective insect growth regulator: halofenozide and heavy metals: cadmium, more toxic and widespread in the region) in mosquitofish: Gambusia affinis. Several approaches were examined: Acute toxicity of cadmium and halofenozide: The acute toxicity of cadmium and halofenozide was examined in juvenile and adult males and females of G. affinis at different concentrations, cadmium causes mortality of the species studied with a relation dose-response. In laboratory conditions, the impact of cadmium was determined on two biomarkers of environmental stress: glutathione and acetylcholinesterase. The results show that the juvenile followed by adult males are more susceptible than adult females, while the halofenozide does not have any effect on the mortality of juvenile and adult males and females of G.affinis. Chronic toxicity of cadmium and halofenozide: both xenobiotics were added to the water fish raising at different doses tested in juveniles and adults males and females during two months of experience. Growth and metric indices; results show that halofenozide added to the water juveniles of G. affinis has no effect on their growth (length and weight). On the other side, the cadmium at the dose 5 µg/L shows a higher toxicity against juvenile, where he appears to reduce significantly their linear growth and weight. In females, the both xenobiotics have significant effects on metric indices, but these effects are more important on the hepatosomatic index that the gonadosomatic index and the coefficient of condition. Biomarkers; acetylcholinesterase (AChE), glutathione S-transferase (GST) and glutathione (GSH) used in assessing of environmental stress were measured in juveniles and adults males and females. The response of these biomarkers reveals an inhibition of AChE specific activity, an induction of GST activity, and decrease of GSH rates in juveniles in the end of experiment and during chronic treatment adult males and females. The effect of these biomarkers is more pronounced in females compared to males and juveniles. These different biomarkers have a similar profile for the duration of exposure.

Keywords: gambusia affinis, insecticide, heavy metal, morphology, biomarkers, chronic toxicity, acute toxicity, pollution

Procedia PDF Downloads 306

Authors: Mehrnaz Mostafavi, Alireza Azani, Mahtab Shabani, Fatemeh Ghafari

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While filled with promise and wonder, space exploration also presents significant challenges, one of the foremost being the threat of cosmic radiation to astronaut health. Recent advancements in assessing these risks and developing protective strategies have shed new light on this issue. Cosmic radiation encompasses a variety of high-energy particles originating from sources like solar particle events, galactic cosmic rays, and cosmic rays from beyond the solar system. These particles, composed of protons, electrons, and heavy ions, pose a substantial threat to human health in space due to the lack of Earth's protective atmosphere and magnetic field. Researchers have made significant progress in assessing the risks associated with cosmic radiation exposure. By employing advanced dosimetry techniques and conducting biological studies, they have gained insights into how cosmic radiation affects astronauts' health, including increasing the risk of cancer and radiation sickness. This research has led to personalized risk assessment methods tailored to individual astronaut profiles. Distinctive protection strategies have been proposed to combat the dangers of cosmic radiation. These include developing spacecraft shielding materials and designs to enhance radiation protection. Additionally, researchers are exploring pharmacological interventions such as radioprotective drugs and antioxidant therapies to mitigate the biological effects of radiation exposure and preserve astronaut well-being. The findings from recent research have significant implications for the future of space exploration. By advancing our understanding of cosmic radiation risks and developing effective protection strategies, we pave the way for safer and more sustainable human missions beyond Earth's orbit. This is especially crucial for long-duration missions to destinations like Mars, where astronauts will face prolonged exposure to cosmic radiation. In conclusion, recent research has marked a milestone in addressing the challenges posed by cosmic radiation in space exploration. By delving into the complexities of cosmic radiation exposure and developing innovative protection strategies, scientists are ensuring the health and resilience of astronauts as they venture into the vast expanse of the cosmos. Continued research and collaboration in this area are essential for overcoming the cosmic radiation challenge and enabling humanity to embark on new frontiers of exploration and discovery in space.

Keywords: Space exploration, cosmic radiation, astronaut health, risk assessment, protective strategies

Procedia PDF Downloads 56

Authors: A. O. Ogunkeyede, D. Amuchi, A. A. Adebayo

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Heavy metal contaminations in soil have received great attention. Anthropogenic activities such as vehicular emission, industrial activities and constructions have resulted in elevated concentration of heavy metals in the surface soils. The metal particles can be free from the surface soil when they are disturbed and re-entrained in air, which necessitated the need to investigate surface soil at market environment where adults and children are present on daily basis. This study assesses concentration of heavy metal pollution, ecological and health risk factors in surface soil at Effurun market. 8 samples were collected at household material (EMH), fish (EMFs), fish and commodities (EMF-C), Abattoir (EMA 1 & 2), fruit sections (EMF 1 & 2) and lastly main road (EMMR). The samples were digested and analyzed in triplicate for contents of Lead (Pb), Nickel (Ni), Cadmium (Cd) and Copper (Cu). The mean concentration of the Pb mg/kg (112.27 ± 1.12) and Cu mg/kg (156.14 ± 1.10) were highest in the abattoir section (EMA 1). The mean concentrations of the heavy metal were then used to calculate the ecological and health risk for people within the market. Pb contamination at EMMR, EMF 2, EMFs were moderately while Pb shows considerable contamination at EMH, EMA 1, EMA 2 and EMF-C sections of the Effurun market. The ecological risk factor varies between low to moderate pollution for Pb and EMA 1 has the highest potential ecological risk that falls within moderate pollution. The hazard quotient results show that dermal exposure pathway is the possible means of heavy metal exposure to the traders while ingestion is the least sources of exposure to adult. The ingestion suggested that children around the EMA 1 have the highest possible exposure to children due to hand-to-mouth and object-to-mouth behaviour. The results further show that adults at the EMA1 will have the highest exposure to Pb due to inhalation during burning of cow with tyre that contained Pb and Cu. The carcinogenic risk values of most sections were higher than acceptable values, while Ni at EMMR, EMF 1 & 2, EMFs and EMF-C sections that were below the acceptable values. The cancer risk for inhalation exposure pathway for Pb (1.01E+17) shows a significant level of contamination than all the other sections of the market. It suggested that the people working at the Abattoir were very prone to cancer risk.

Keywords: carcinogenic, ecological, heavy metal, risk

Procedia PDF Downloads 137

Authors: Rahul Saraswat

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More recently, a focus has been given to replacing machined stainless steel metal flow fields with inexpensive wire mesh current collectors. The flow fields are based on simple woven wire mesh screens of various stainless steels, which are sandwiched between a thin metal plate of the same material to create a bipolar plate/flow field configuration for use in a stack. Major advantages of using stainless steel wire screens include the elimination of expensive raw materials as well as machining and/or other special fabrication costs. The objective of the project is to improve the performance of the passive direct methanol fuel cell without increasing the cost of the cell and to make it as compact and light as possible. From the literature survey, it was found that very little is done in this direction, and the following methodology was used. 1. The passive direct methanol fuel cell (DMFC) can be made more compact, lighter, and less costly by changing the material used in its construction. 2. Controlling the fuel diffusion rate through the cell improves the performance of the cell. A passive liquid feed direct methanol fuel cell (DMFC) was fabricated using a given MEA (Membrane Electrode Assembly) and tested for different current collector structures. Mesh current collectors of different mesh densities along with different support structures, were used, and the performance was found to be better. Methanol concentration was also varied. Optimisation of mesh size, support structure, and fuel concentration was achieved. Cost analysis was also performed hereby. From the performance analysis study of DMFC, we can conclude with the following points: Area specific resistance (ASR) of wire mesh current collectors is lower than the ASR of stainless steel current collectors. Also, the power produced by wire mesh current collectors is always more than that produced by stainless steel current collectors. 1. Low or moderate methanol concentrations should be used for better and stable DMFC performance. 2. Wiremesh is a good substitute for stainless steel for current collector plates of passive DMFC because of its lower cost (by about 27 %), flexibility, and light in weight characteristics of wire mesh.

Keywords: direct methanol fuel cell, membrane electrode assembly, mesh, mesh size, methanol concentration, support structure

Procedia PDF Downloads 74

Authors: Eugene Y. J. Aw, J. W. Koh, S. H. Chew, K. E. Chua, P. L. Goh, Grace H. B. Foo, M. L. Leong

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This paper presents the evaluation of various soil testing methods such as the four-probe soil electrical resistivity method and cone penetration test (CPT) that can complement a newly developed novel rapid soil classification scheme using computer vision, to improve the accuracy and productivity of on-site classification of excavated soil. In Singapore, excavated soils from the local construction industry are transported to Staging Grounds (SGs) to be reused as fill material for land reclamation. Excavated soils are mainly categorized into two groups (“Good Earth” and “Soft Clay”) based on particle size distribution (PSD) and water content (w) from soil investigation reports and on-site visual survey, such that proper treatment and usage can be exercised. However, this process is time-consuming and labor-intensive. Thus, a rapid classification method is needed at the SGs. Four-probe soil electrical resistivity and CPT were evaluated for their feasibility as suitable additions to the computer vision system to further develop this innovative non-destructive and instantaneous classification method. The computer vision technique comprises soil image acquisition using an industrial-grade camera; image processing and analysis via calculation of Grey Level Co-occurrence Matrix (GLCM) textural parameters; and decision-making using an Artificial Neural Network (ANN). It was found from the previous study that the ANN model coupled with ρ can classify soils into “Good Earth” and “Soft Clay” in less than a minute, with an accuracy of 85% based on selected representative soil images. To further improve the technique, the following three items were targeted to be added onto the computer vision scheme: the apparent electrical resistivity of soil (ρ) measured using a set of four probes arranged in Wenner’s array, the soil strength measured using a modified mini cone penetrometer, and w measured using a set of time-domain reflectometry (TDR) probes. Laboratory proof-of-concept was conducted through a series of seven tests with three types of soils – “Good Earth”, “Soft Clay,” and a mix of the two. Validation was performed against the PSD and w of each soil type obtained from conventional laboratory tests. The results show that ρ, w and CPT measurements can be collectively analyzed to classify soils into “Good Earth” or “Soft Clay” and are feasible as complementing methods to the computer vision system.

Keywords: computer vision technique, cone penetration test, electrical resistivity, rapid and non-destructive, soil classification

Procedia PDF Downloads 228

Authors: Mohd Shazad, Kamal Kumar Gupta

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Aedes aegypti (Diptera: Culicidae), commonly known as tiger mosquito is the vector of dengue fever, yellow fever, chikungunya and zika virus. In the absence of any effective vaccine against these diseases, control the mosquito population is the only promising mean to prevent the diseases. Currently used chemical insecticides cause environmental contamination, high mammalian toxicity and hazards to non-target organisms, insecticide resistance and vector resurgence. Present research work aimed to explore the potentials of phytochemicals present in the Ocimum sanctum in management of mosquito population. The leaves of Ocimum were extracted with ethanol by ‘cold extraction method’. 0-24h old fourth instar larvae of Aedes aegypti were treated with the extract of concentrations 50ppm, 100ppm, 200ppm and 400ppm for 24h. Survival, growth and development of the treated larvae were evaluated. The adults emerged from the treated larvae were used for the reproductive fitness studies. Our results indicate 77.2% mortality in the larvae exposed to 400 ppm. At lower doses, although there was no significant reduction in the survival after 24h however, it decreased during subsequent days of observations. In control experiments, no mortality was observed. It was also observed that the larvae survived after treatment showed severe growth and developmental abnormalities. There was significant increase in larval duration. In control, fourth instar moulted into pupa after 3 days while larvae treated with 400 ppm extract were moulted after 4.6 days. Larva-pupa intermediates and the pupa-adult intermediates were observed in many cases. The adults emerged from the treated larvae showed impaired mating and oviposition behaviour. The females exhibited longer preoviposition period, reduced oviposition rate and decreased egg output. GCMS analysis of the ethanol extract revealed presence of JH mimics and intermediates of JH biosynthetic pathway. Potentials of Ocimum sanctum in integrated vector management programme of Aedes aegypti were discussed.

Keywords: Aedes aegypti, Ocimum sanctum, oviposition, survival

Procedia PDF Downloads 178

Authors: Raviv Harris, Maggie Levy

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Natural product-based pesticides may serve as an alternative to the traditional synthetic pesticides, which have a potentially damaging effect, both to human health and for the environment. Along with plants, microorganisms are a prospective source of such biological pesticides. A unique and active strain of P. aphidis (designated isolate L12, Israel 2004), an epiphytic and non-pathogenic basidiomycete yeast, was isolated in our lab from strawberry leaves. P. aphidis L12 secretions were found to inhibit broad range of plant pathogens. This work demonstrates that metabolites isolated from the biocontrol agent P. aphidis (isolate L12) can inhibit varied fungal and bacterial phytopathogens. Biologically active metabolites were extracted from P. aphidis biomass, using the organic solvent ethyl acetate. The antimicrobial activity of the extract was demonstrated, both in vitro and in planta. Using disk diffusion assays, the following inhibition zones were obtained: 43cm² for Pseudomonas syringae pv. tomato, 28.5cm² for Xanthomonas campestris pv. vesicatoria, 59cm² for Clavibacter michiganensis subsp. michiganensis, 34cm² for Erwinia amylovora and 34cm² for Agrobacterium tumefaciens. Additionally, strong inhibitory activity of the extract against fungi mycelial growth was established, with IC₅₀ values of 606µg ml⁻¹ for Botrytis cinerea, 221µg ml⁻¹ for Pythium spp., 519µg ml⁻¹ for Rhizoctonia solani, 455µg ml⁻¹ for Sclerotinia sclerotiorum, 2270µg ml⁻¹ for Fusarium oxysporum f. sp. lycopersici, and 2038µg ml⁻¹ for Alternaria alternata. The results of the in planta experiments demonstrated a dose-dependent reduction in disease infection. Significant inhibition of B. cinerea lesions on tomato plants was obtained when a spore suspension of this pathogen was treated with extract concentrations higher than 4.2mg ml⁻¹. Concentration of 7mg ml⁻¹ caused a reduction of over 95% in the lesion size of B. cinerea on tomato plants. The strong antimicrobial activity demonstrated both in vitro and in planta against varied phytopathogens, may indicate that the extracted antimicrobial metabolites have potential to serve as natural pesticides in the field.

Keywords: antimicrobial, B. cinerea, metabolites, natural pesticides, P. aphidis

Procedia PDF Downloads 227

Authors: Imen Blibech, Mohieddine Ksantini, Manohar Shete

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Bactrocera oleae is one of the most economically damaging insects of olive in Tunisia and other producing countries of olive trees. As a reliable alternative to synthetic chemical insecticides, botanical insecticides are considered natural control methods safe for the environment and human health. The certified botanical insecticide ULTRA-ACT® effectively on large scale of insects is approved per Indian and International organic standards certified organic pesticides. Olives with signs of olive fly infestation were collected from productive olive trees in three Sahel localities of Tunisia. Infested fruits were separated daily for larval stage control purposes, into new rearing boxes under microclimatic conditions at 75% R.H, 25 ± 3°C and 8 L-16D. Treatment with ULTRA-ACT® extract solutions was made by dipping methods; each fruit was pipetted in 5 mL of extract for 10 seconds then air- dried. Five doses of ULTRA-ACT® were used for a bioassay, plus a water-only control. A total of 200 infested olive fruits were treated in separate dishes with a proportion of 10 olives per dish. A total of 20 dishes were used for each concentration treatment as well as 20 dished utilized as control. The bioassay was conducted with 3 replicates. The development of the larval and pupal stages was recorded since the egg hatching until emergence of adults. It was determined that ULTRA-ACT® extracts on succeeding concentrations; 0.25, 0.5, 1 and 2% show significant effect on the biology of the pest. Increased concentration decreased significantly adult emergence from pupae and affect the egg hatchability percentage. Therefore, larval mortality increased insignificantly with the increase of the product concentration. The 2nd instar larvae were more susceptible to the product and after 72 hours the maximum mortality (75%) was observed with ULTRA-ACT® 2%. The present work aimed to give a possible and efficient alternative solution for B. oleae biological control with a promising botanical insecticide.

Keywords: Bactrocera oleae, olive insect pest, Ultra Act®, larval mortality, pupal emergency, biological control

Procedia PDF Downloads 131

Authors: V. Kumar, K. Jha

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The present study is done to explore design modifications of the vortex finder, as it has a significant effect on the cyclone separator performance. It is evident that modifications of the vortex finder improve the performance of the cyclone separator significantly. The study conducted strives to improve the overall performance of cyclone separators by utilizing a converging-diverging (CD) vortex finder instead of the traditional uniform diameter vortex finders. The velocity and pressure fields inside a Stairmand cyclone separator with body diameter 0.29m and vortex finder diameter 0.1305m are calculated. The commercial software, Ansys Fluent v14.0 is used to simulate the flow field in a uniform diameter cyclone and six cyclones modified with CD vortex finders. Reynolds stress model is used to simulate the effects of turbulence on the fluid and particulate phases, discrete phase model is used to calculate the particle trajectories. The performance of the modified vortex finders is compared with the traditional vortex finder. The effects of the lengths of the converging and diverging sections, the throat diameter and the end diameters of the convergent divergent section are also studied to achieve enhanced performance. The pressure and velocity fields inside the vortex finder are presented by means of contour plots and velocity vectors and changes in the flow pattern due to variation of the geometrical variables are also analysed. Results indicate that a convergent-divergent vortex finder is capable of decreasing the pressure drop than that achieved through a uniform diameter vortex finder. It is also observed that the end diameters of the CD vortex finder, the throat diameter and the length of the diverging part of the vortex finder have a significant impact on the cyclone separator performance. Increase in the lower diameter of the vortex finder by 66% results in 11.5% decrease in the dimensionless pressure drop (Euler number) with 5.8% decrease in separation efficiency. Whereas 50% decrease in the throat diameter gives 5.9% increase in the Euler number with 10.2% increase in the separation efficiency and increasing the length of the diverging part gives 10.28% increase in the Euler number with 5.74% increase in the separation efficiency. Increasing the upper diameter of the CD vortex finder is seen to produce an adverse effect on the performance as it increases the pressure drop significantly and decreases the separation efficiency. Increase in length of the converging is not seen to affect the performance significantly. From the present study, it is concluded that convergent-divergent vortex finders can be used in place of uniform diameter vortex finders to achieve a better cyclone separator performance.

Keywords: convergent-divergent vortex finder, cyclone separator, discrete phase modeling, Reynolds stress model

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Authors: Suboohi Nasrin, MHD. Shahid, Abduraheem K.

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India is a tropical country, and it is estimated that biological and abiological agents are the major factors in the destruction and deterioration of archival materials like herbarium, paper, cellulose, bookbinding, etc. Silverfish, German Cockroaches, Termites, Booklice, Tobacco beetle and Carpet beetles are the common insect's pests in the museum, which causes deterioration to collections of museum specimens. Among them, silverfish is one of the most notorious pests and primarily responsible for the deterioration of Archival materials. So far, the investigation has been carried to overcome this existing problem as different management strategies such as chemical insecticides, fungicides, herbicides, nematicides, etc., have been applied. Moreover, Synthetic molecules lead to affect the ecological balance, have a detrimental effects on human health, reduce the beneficial microbial flora and fauna, etc. With a view, numbers of chemicals have been banned and advised not to be used due to their long-lasting persistency in soil ecosystem, water and carcinogenic. That’s why the authors used natural products with biocidal activity, cost-effective and eco-friendly approaches. In this study, various concentrations (30, 60 and 90 ml/L) of clove and lemongrass essential oil at different treatment duration (30, 60, 90 and 120-minutes) were investigated to test its properties as a silverfish repellent and insecticidal effect. The result of two ways ANOVA revealed that the mortality was significantly influenced by oil concentration, treatment duration and interaction between two independent factors was also found significant. The mortality rate increased with increasing the oil concentration in clove oil, and 100 % mortality was recorded in 0.9 ml at 120-minute. It was also observed that the treatment duration has the highest effect on the mortality rate of silverfish. The clove oil had the greatest effect on the silverfish in comparison to lemongrass. While in the case of percentage, repellency of adult silverfish was oil concentration and treatment duration-dependent, i.e., increase in concentration and treatment duration resulted in higher repellency percentage. The clove oil was found more effective, showing maximum repellency of 80.00% at 0.9ml/cm2 (highest) concentration, and in lemongrass highest repellency was observed at 33.4% at 0.9 ml/cm2 concentration in the treated area.

Keywords: adult silverfish, oils, oil concentration, treatment duration, mortality (%) and repellency

Procedia PDF Downloads 162