Search results for: formation and concentration and growth of TiC

Authors: Amir Ali, Laura Yael Mendoza

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The application of nanomaterials is becoming the most effective strategy of elicitation to produce a desirable level of plant biomass with complex medicinal compounds. This study was designed to check the influence of phytosynthesized iron nanoparticles (FeNPs) on physical growth characteristics, antioxidant status, and production of steviol glycosides of in vitro grown Stevia rebaudiana. Effect of different concentrations of iron nanoparticles replacement of iron sulfate in MS medium (stock solution) on invitro stevia plant growth following positive control (MS basal medium), negative control (iron sulfate devoid medium), iron sulfate devoid MS medium and supplemented with FeNPs at different concentrations (5.6 mg/L, 11.2 mg/L, 16.8 mg/L, 22.4 mg/L) was evaluated. The iron deficiency leads to a drastic reduction in plant growth. In contrast, applying FeNPs leads to improvement in plant height, leave diameter, improved leave morphology, etc., in a concentration-dependent manner. Furthermore, the stress caused by FeNPs at 16.8 mg/L in cultures produced higher levels of total phenolic content (3.7 ± 0.042 mg/g dry weight: DW) and total flavonoid content (1.9 ± 0.022 mg/g DW and antioxidant activity (78 ± 4.6%). In addition, plants grown in the presence of FeNPs at 22.4 mg/L resulted in higher enzymatic antioxidant activities (SOD = 3.5 ± 0.042 U/mg; POD = 2.6 ± 0.026 U/mg; CAT = 2.8 ± 0.034 U/mg and APx = 3.6 ± 0.043 U/ mg), respectively. Furthermore, exposure to a higher dose of FeNPs (22.4 mg/L) exhibited the maximum amount of stevioside (stevioside: 4.6 ± 0.058 mg/g (DW) and rebaudioside A: 4.9 ± 0.068 mg/g DW) as compared to other doses. The current investigation confirms the effectiveness of FeNPs in growth media. It offers a suitable prospect for commercially desirable production of S. rebaudiana biomass with higher sweet glycosides profiles in vitro.

Keywords: cell culture, stevia, iron nanoparticles, antioxidants

Procedia PDF Downloads 72

Authors: Sadeg Abdurahman, Claudio Stockle, James Harsh, Marc Beutel, Usama Zaher

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Pollution of the environment is a phenomenon which has taken a big part of importance of the world governments since the second half of the last century, this takes dangerous environmental, economic and social ranges dimensions especially after industrial advancement in industrialized country and good industrial expansion supported with modern technology and as chromium is known to be used in tannery factories. Chromium is considered a harm element to the environment due to its danger and transference through food, air, and water to the plants, animals and people. In this study the capacity of Arundo donax against chromium pollution was conducted. A. donax plants were grown-up under greenhouse conditions in pots contain nursery soil and feeding by Cr synthetic wastewater (0, 0.1, 1.0 and 2.0 mg L-1 ) for four weeks. Leaves, roots and stems dry matter production, color degree values, chlorophyll, growth parameters, and morphological characters were measured. The high Cr concentration was in roots was 1.15 mg kg-1 . Similarly, Cr concentration in stem was 0.469 mg kg-1 at 2.0 mg L-1 supplied Cr. In case of leaves, the maximum Cr concentration was 0.345 mg kg-1 at 2.0 g L-1 supplied Cr. The bioaccumulation and translocation factors was calculated. The macrophyte A. donax L. may be considered to be the most promising plant species in remediation of Cr-contaminated soil and wastewater due to its deeper root system as well as has higher efficiency to absorb chromium and other heavy metals as well.

Keywords: Arundo donax, Chromium pollution, heavy metals, phytoremediation, wastewater

Procedia PDF Downloads 647

Authors: Vijay Kumar, Jaspreet Singh, Manoj Wadhwa

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Piezo-resistive pressure sensors were one of the first developed micromechanical system (MEMS) devices and still display a significant growth prompted by the advancements in micromachining techniques and material technology. In MEMS based piezo-resistive pressure sensors, temperature can be considered as the main environmental condition which affects the system performance. The study of the thermal behavior of these sensors is essential to define the parameters that cause the output characteristics to drift. In this work, a study on the effects of temperature and doping concentration in a boron implanted piezoresistor for a silicon-based pressure sensor is discussed. We have optimized the temperature coefficient of resistance (TCR) and temperature coefficient of sensitivity (TCS) values to determine the effect of temperature drift on the sensor performance. To be more precise, in order to reduce the temperature drift, a high doping concentration is needed. And it is well known that the Wheatstone bridge in a pressure sensor is supplied with a constant voltage or a constant current input supply. With a constant voltage supply, the thermal drift can be compensated along with an external compensation circuit, whereas the thermal drift in the constant current supply can be directly compensated by the bridge itself. But it would be beneficial to also compensate the temperature coefficient of piezoresistors so as to further reduce the temperature drift. So, with a current supply, the TCS is dependent on both the TCπ and TCR. As TCπ is a negative quantity and TCR is a positive quantity, it is possible to choose an appropriate doping concentration at which both of them cancel each other. An exact cancellation of TCR and TCπ values is not readily attainable; therefore, an adjustable approach is generally used in practical applications. Thus, one goal of this work has been to better understand the origin of temperature drift in pressure sensor devices so that the temperature effects can be minimized or eliminated. This paper describes the optimum doping levels for the piezoresistors where the TCS of the pressure transducers will be zero due to the cancellation of TCR and TCπ values. Also, the fabrication and characterization of the pressure sensor are carried out. The optimized TCR value obtained for the fabricated die is 2300 ± 100ppm/ᵒC, for which the piezoresistors are implanted at a doping concentration of 5E13 ions/cm³ and the TCS value of -2100ppm/ᵒC is achieved. Therefore, the desired TCR and TCS value is achieved, which are approximately equal to each other, so the thermal effects are considerably reduced. Finally, we have calculated the effect of temperature and doping concentration on the output characteristics of the sensor. This study allows us to predict the sensor behavior against temperature and to minimize this effect by optimizing the doping concentration.

Keywords: piezo-resistive, pressure sensor, doping concentration, TCR, TCS

Procedia PDF Downloads 164

Authors: Temitope L. A. Leshoro

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This study explored several variables that enhance economic growth in South Africa, based on different growth theories while using the vector error correction model (VECM) technique. The impacts and contributions of each of these variables on GDP in South Africa were investigated. The motivation for this study was as a result of the weak economic growth that the country has been experiencing lately, as well as the continuous increase in unemployment rate and deteriorating health care system. Annual data spanning over the period 1974 to 2013 was employed. The results showed that the major determinants of GDP are trade openness, government spending, and health indicator; as these variables are not only economically significant but also statistically significant in explaining the changes in GDP in South Africa. Policy recommendations for economic growth enhancement are suggested based on the findings of this study.

Keywords: economic growth, GDP, investment, health indicator, VECM

Procedia PDF Downloads 252

Authors: Inga Balarjishvili, Ia Natsvlishvili

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Article aims to discuss the controversial character of the institutional preferences of elites and society in modern Georgia. Desktop research method is used to formulate the findings and analyze the outcomes. It is accepted that transformation process in Post-Soviet Georgia went with the prevalence of elites’ institutional preferences over the needs of the society that induced voluntarism in the process of formation of institutions. Hypothesis of 'quasi-inclusion trap' is put forward in the article as an effect of authoritarian modernization that is proved by instable paces of wealth and economic growth in the post-authoritarian period. On the one hand, monopolization of institutional choice by the elites, blocking formation of inclusive political and economic institutions for fear of losing status-quo worsen perspectives for achieving free availability regime. On the other hand, consciousness of the society is dominated by informal institutions, judicial nihilism and orientation on 'self-survival values.' This hinders its consolidation as a 'collective principal' against 'institutional utilitarianism,' result of which is hindered economic development.

Keywords: elites, hypothesis of 'quasi-inclusion trap', institutional preferences, post-Soviet Georgia

Procedia PDF Downloads 233

Authors: S. F. Afzali, W. L. Wong

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The epizootic ulcerative syndrome (EUS) causes by the oomycete fungus, Aphanomyces invadans; known to be one of the infectious fish diseases for farmed and wild fishes in fresh and brackish-water from the Asia-pacific region, America and Africa. Although, EUS had been documented by the Office International des Epizooties (OIE) since 1995, hitherto, there is neither standard chemical agents that can be used for successful treatment of this destructive infection in the time of outbreak; nor available vaccine for prevention. Plant-based remedies in controlling fish diseases are gaining much attention recently as an alternative to chemical treatments, which possess negative effects to the environment and human. In present study, Sonneratia alba, a mangrove plant belongs to the Sonneratiaceae family, was screened in vitro and in vivo for its antifungal activity against A. invadans mycelium growth and its effects on fish innate immune system and disease resistant. The in vitro tests was performed using the disc diffusion methods with measurements of minimum inhibitory concentration (MIC) and inhibition zone. For in vivo study, the S. alba extract supplemented diets were administrated at 0.0, 1.0%, 3.0%, and 5.0% on healthy goldfish, Carassius auratus, which challenged with A. invadans zoospores (100 spores/ml). To compare the significant differences in the hematological and immunological parameters obtained from the experiments, the data were analysed using the SPSS. The methanol extract of S. alba effectively inhibited the mycelial growth of A. invadans at a minimum concentration of 1000 ppm for agar and filter paper diffusion experiments. In the agar diffusion test, 500 ppm of the extract inhibited the fungus mycelial growth up to 96 hours after exposure. The mycelial growth from the edge of the pre-inoculated A. invadans agar discs treated with S. alba extracts at concentrations of 100, 500 and 1000 ppm were 15, 8 and 0 mm respectively. The results of the filter paper disc test showed that the S. alba extract at its minimal inhibitory concentration (1000 ppm) has similar qualitative inhibitory effect as malachite green at 1 ppm and formalin at 250 ppm. According to the in vivo tests findings, in the infected fish fed with 3.0% and 5.0% supplementation diet, the numbers of white blood cell and myeloperoxidase activity significantly increased after the second week of treatment. Whilst the numbers of red blood cell significantly decreased in the infected fish fed with 0.0 and 1.0% supplementation diet. After the third week of feeding, significant increases in the total protein, albumin level, lysozyme activity were recorded in the infected fish fed with 3.0% and 5.0% supplementation diet. Also, the enriched diets increased the survival rate as compared to the untreated group that suffered from 90% mortality. The present study indicated that S. alba extract may inhibit the mycelial growth of A. invadans effectively, suggesting an alternative to other chemotherapeutic agents, which brought much environmental and health concerns to the public, for EUS treatment.

Keywords: fungal pathogen, goldfish, organic extract, treatment

Procedia PDF Downloads 259

Authors: Gopal Ji, Priyanka Dwivedi, Shanthi Sundaram, Rajiv Prakash

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Inhibition effect of aqueous Argemone Mexicana root extract (AMRE) on mild steel corrosion in 1 M HCl has been studied by weight loss, Tafel polarization curves, electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) and atomic force microscopy (AFM) techniques. Results indicate that inhibition ability of AMRE increases with the increasing amount of the extract. A maximum corrosion inhibition of 94% is acknowledged at the extract concentration of 400 mg L-1. Polarization curves and impedance spectra reveal that both cathodic and anodic reactions are suppressed due to passive layer formation at metal-acid interface. It is also confirmed by SEM micro graphs and FTIR studies. Furthermore, the effects of acid concentration (1-5 M), immersion time (120 hours) and temperature (30-60˚C) on inhibition potential of AMRE have been investigated by weight loss method and electrochemical techniques. Adsorption mechanism is also proposed on the basis of weight loss results, which shows good agreement with Langmuir isotherm.

Keywords: mild steel, polarization, SEM, acid corrosion, EIS, green inhibition

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Authors: Maryam Maimota

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Words are the basic building blocks of a language. In everyday usage of a language, words are used and new words are formed and reformed in order to contain and accommodate all entities, phenomena, qualities and every aspect of the entire human life. This research study seeks to examine and compare some of the word formation processes and how they are used in forming new words in English and Hausa languages. The study focuses its main attention on blending and compounding as word formation processes and how the processes are used adequately in the formation of words in both English and Hausa languages. The research aims to find out, how compounding and blending are used, as processes of word formation in these two languages. And also, to investigate the word formation processes involved in compounding and blending in these languages, and the nature of words that are formed. Therefore, the research tries to find the answers to the following research questions; What types of compound and blended forms are found and how they are formed in the English and Hausa languages? How these compounded and blended forms functioned in both English and Hausa languages in different context such as in phrases and sentences structures? Findings of the study reveal that, there exist new kind of words formed in Hausa and English language under blending, which previous findings did not either reveal or explain in detail. Similarly, there are a lot of similarities found in the way these blends and compounds forms in the two languages, however, the data available shows that, blends in the Hausa language are more, when compared to the blends in English. The data of this study will be gathered based on discourse found in newspaper, articles, novels, and written literature of the Hausa and English languages.

Keywords: blending, compounding, morphology, word formation

Procedia PDF Downloads 352

Authors: Maria Manzoor, Iram Gul, Muhammad Arshad, Jean Kallerhoff

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The potential of fungal isolates to be used in phytoremediation of widespread lead contaminated soil has been evaluated in this study. Five different fungal isolates (Trichoderma harzianum, Penicillium simplicissimum, Aspergillus flavus, Aspergillus niger and Mucor spp.) were obtained and tested for their tolerance to increasing concentration of lead (Pb) i.e. 100, 200, 300, 400 and 500 mgL-1 on PDA and PDB culture experiment. All strains were tolerant up to 500 mgL-1 following sequence; A. flavus > A. niger > Mucor spp. > P. simplicissimum > T. harzianum. Further the isolates were then monitored for possible effect on Pb solubility/mobility through soil incubation experiments and characterized for essays including pathogenicity, germination and root elongation and plant growth promoting activities including IAA (indole acetic acid), phosphorus solubilization and gibberellic acid (GA3) production. Results revealed that fungal isolates have positive effect on Pb mobility in soil and plant biomass production. Pb solubility was significantly (P> 0.05) increased in soil upon application of Mucor spp. P. simplicissimum and T. harzianum. when compared to control. Among different strains three isolates (Mucor spp., P. simplicissimum and T. harzianum) were nonpathogenic because no inhibitory effect of fungus was observed to plant growth when exposed to these strains in root shoot elongation essay. Particularly T. harzianum and P. simplicissimum showed great ability to increase root length by 1.1 and 1.3 folds and shoot length by 1.47 and 1.5 folds respectively under Pb stress (500 mgL-1). Significantly high production of IAA was observed in A. niger (26.7 μg/ml), Phosphorus solubilization was observed in T. harzianum (9.15 μg/ml) and GA3 production was observed in P. simplicissimum (11.02 μg/ml). From results it is concluded that Mucor spp., P. simplicissimum and T. harzianum have potential to increase Pb mobility and improving plant growth under highy Pb contamination, therefore can be used in microbially assisted phytoremediation of Pb contaminated soil.

Keywords: Pb tolerant fungus, Pb mobility, plant growth promoting activities, indole acetic acid (IAA)

Procedia PDF Downloads 249

Authors: Gabriel Wosiak, Jeyse da Silva, Sthefany S. Sena, Renato N. de Andrade, Ernesto Pereira

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The bubble formation during hydrogen production by electrolysis and several electrochemical processes is an inherent phenomenon and can impact the energy consumption of the processes. In this work, it was reported both experimental and computational results describe the effect of bubble displacement, which, under the cases investigated, leads to the formation of a convective flow in the solution. The process is self-sustained, and a solution vortex is formed, which modifies the bubble growth and covering at the electrode surface. Using the experimental data, we have built a model to simulate it, which, with high accuracy, describes the phenomena. Then, it simulated many different experimental conditions and evaluated the effects of the boundary conditions on the bubble surface covering the surface. We have observed a position-dependent bubble covering the surface, which has an effect on the water-splitting efficiency. It was shown that the bubble covering is not uniform at the electrode surface, and using statistical analysis; it was possible to evaluate the influence of the gas type (H2 and O2), current density, and the bubble size (and cross-effects) on the covering fraction and the asymmetric behavior over the electrode surface.

Keywords: water splitting, bubble, electrolysis, hydrogen production

Procedia PDF Downloads 73

Authors: B. Guezzen, M.A. Didi, B. Medjahed

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A factorial design of experiments and a response surface methodology were implemented to investigate the liquid-liquid extraction process of zinc (II) from acetate medium using the 1-Butyl-imidazolium di(2-ethylhexyl) phosphate [BIm⁺][D2EHP^-]. The optimization process of extraction parameters such as the initial pH effect (2.5, 4.5, and 6.6), ionic liquid concentration (1, 5.5, and 10 mM) and salt effect (0.01, 5, and 10 mM) was carried out using a three-level full factorial design (3³). The results of the factorial design demonstrate that all these factors are statistically significant, including the square effects of pH and ionic liquid concentration. The results showed that the order of significance: IL concentration > salt effect > initial pH. Analysis of variance (ANOVA) showing high coefficient of determination (R² = 0.91) and low probability values (P < 0.05) signifies the validity of the predicted second-order quadratic model for Zn (II) extraction. The optimum conditions for the extraction of zinc (II) at the constant temperature (20 °C), initial Zn (II) concentration (1mM) and A/O ratio of unity were: initial pH (4.8), extractant concentration (9.9 mM), and NaCl concentration (8.2 mM). At the optimized condition, the metal ion could be quantitatively extracted.

Keywords: ionic liquid, response surface methodology, solvent extraction, zinc acetate

Procedia PDF Downloads 353

Authors: Zubda Zia, Zainab Masood

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This study has investigated the relationship between renewable energy, urbanization, industrialization, and economic growth in Pakistan, through the years 1990-2016. All the three explanatory variables play a pivotal role in their contribution to growth in any economy, especially a developing one such as Pakistan. Auto-regressive distributive lag (ARDL) model has been used to determine the co-integration and relationship between the variables. The empirical results indicate that there exists a positive and significant relationship between all the three variables and economic growth and that there is a stable, long-run relationship among them. Policy suggestions that incorporate the results include having a larger share of renewable energy in the energy sector, using urbanization as a means to remove the big city trend and move towards, smaller sustainable cities, etc.

Keywords: economic growth, energy crisis, industrialization, renewable energy, SGDs, urbanization

Procedia PDF Downloads 164

Authors: Frantisek Odvarka

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Based on the data from the Moravian Karst, the influence of the calcite speleothem growth by selected meteorological factors was evaluated. External temperature was determined as one of the main factors influencing speleothem growth in Moravian Karst. This factor significantly influences the CO₂ concentration in soil/epikarst, and cave atmosphere in the Moravian Karst and significantly contributes to the changes in the CO₂ partial pressure differences between soil/epikarst and cave atmosphere in Moravian Karst, which determines the drip water supersaturation with respect to the calcite and quantity of precipitated calcite in the Moravian Karst cave environment. External air temperatures and cave air temperatures were measured using a COMET S3120 data logger, which can measure temperatures in the range from -30 to +80 °C with an accuracy of ± 0.4 °C. CO₂ concentrations in the cave and soils were measured with a FT A600 CO₂H Ahlborn probe (value range 0 ppmv to 10,000 ppmv, accuracy 1 ppmv), which was connected to the data logger ALMEMO 2290-4, V5 Ahlborn. The soil temperature was measured with a FHA646E1 Ahlborn probe (temperature range -20 to 70 °C, accuracy ± 0.4 °C) connected to an ALMEMO 2290-4 V5 Ahlborn data logger. The airflow velocities into and out of the cave were monitored by a FVA395 TH4 Thermo anemometer (speed range from 0.05 to 2 m s⁻¹, accuracy ± 0.04 m s⁻¹), which was connected to the ALMEMO 2590-4 V5 Ahlborn data logger for recording. The flow was measured in the lower and upper entrance of the Imperial Cave. The data were analyzed in MS Office Excel 2019 and PHREEQC.

Keywords: speleothem growth, carbon dioxide partial pressure, Moravian Karst, external temperature

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Authors: Waleed Sulaiman Shingaly

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The Ordivician-Khabour Formation from the Northern Thrust Zone of Iraqi-Kurdistan comprises between 500 and 800 m of alternating predominantly greenish-grey sandstones, siltstones and shales. The succession has revealed an abundant ichnofossils characterized by 11 ichnogenus, namely: Helminthopsis, Gordia, Cruziana, Rusophycus, Monomorphichnus, Rhizocorallium, Thalassinoide, Planolite, Paleophycus, Deplocraterion and Skolithose. Ethologically these ichnogenera display dwelling and feeding activities of the infaunal organisms. This association of ichnofossils contains elements of the Skolithose and Cruziana ichnofacies. The presence of Skolithos ichnofacies indicates sandy shifting substrate and high energy conditions in foreshore zone while the Cruziana ichnofacies indicate unconsolidated, poorly sorted soft substrate and low energy condition in the shore face/offshore zone. These ichnogenera indicate shoreface-offshore zone of shallow-marine environment for the deposition of the rocks of the Khabour Formation.

Keywords: Ichnofossils, shoreface-offshore zone, Khabour Formation, Iraq

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Authors: Godwin Chigozie Okpara, William Chimee Nwaoha

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The paper set out to stress on how financial inclusion index could be calculated and also investigated the impact of inclusive finance on inclusive growth in an emerging economy. In the light of these objectives, chi-wins method was used to calculate indexes of financial inclusion while co-integration and error correction model were used for evaluation of the impact of financial inclusion on inclusive growth. The result of the analysis revealed that financial inclusion while having a long-run relationship with GDP growth is an insignificant function of the growth of the economy. The speed of adjustment is correctly signed and significant. On the basis of these results, the researchers called for tireless efforts of government and banking sector in promoting financial inclusion in developing countries.

Keywords: chi-wins index, co-integration, error correction model, financial inclusion

Procedia PDF Downloads 629

Authors: Mukunda Upreti, Jill Storry, Rafael Björk, Emilie Louvet, Johan Normark, Sven Bergström

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Borrelia duttonii and most other relapsing fever species are Gram-negative bacteria which cause a blood borne infection characterized by the binding of bacterium to erythrocytes. The bacteria associate with two or more erythrocytes to form clusters of cells into rosettes. Rosetting is a major virulence factor and the mechanism is believed to facilitate persistence of bacteria in the circulatory system and the avoidance of host immune cells through masking or steric hindrance effects. However, the molecular mechanisms of rosette formation are still poorly understood. This study aims at determining the molecules involved in the rosette formation phenomenon. Fractionated serum, using different affinity purification methods, was investigated as a rosetting agent and IgG and at least one other serum components were needed for rosettes to form. An IgG titration curve demonstrated that IgG alone is not enough to restore rosette formation level to the level whole serum gives. IgG hydrolysis by IdeS ( Immunoglobulin G-degrading enzyme of Streptococcus pyogenes) and deglycosylation using N-Glycanase proved that the whole IgG molecule regardless of saccharide moieties is critical for Borrelia induced rosetting. Complement components C3 and C4 were also important serum molecules necessary to maintain optimum rosetting rates. The deactivation of complement network and serum depletion with C3 and C4 significantly reduced the rosette formation rate. The dependency of IgG and complement components also implied involvement of the complement receptor (CR1). Rosette formation test with Knops null RBC and sCR1 confirmed that CR1 is also part of Borrelia induced rosette formation.

Keywords: complement components C3 and C4, complement receptor 1, Immunoglobulin G, Knops null, Rosetting

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Authors: Muhammad Rafi Ullah Khan, Yaodong Guo, Vanee Chonhenchob, Jinjin Pei, Chongxing Huang

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The effect of sodium alginate (1%) based edible coating incorporated natural essential oils; thymol, carvone and carvacrol as antimicrobial agents at different concentrations (0.1, 0.5 and 1.0 %) on the quality changes of fresh-cut pineapple were investigated. Pineapple dipped in distilled water was served as control. After coating, fruit were sealed in a modified atmosphere package (MAP) using high permeable film; and stored at 5 °C. Gas composition in package headspace, color values (L*, a*, b*, C*), TSS, pH, ethanol, browning, and microbial decay were monitored during storage. Oxygen concentration continuously decreased while carbon dioxide concentration inside all packages continuously increased over time. Color parameters (L*, b*, c*) decreased and a* values increased during storage. All essential oils significantly (p ≤ 0.05) prevented microbial growth than control. A significantly higher (p ≤ 0.05) ethanol content was found in the control than in all other treatments. Visible microbial growth, high ethanol, and low color values limited the shelf life to 6 days in control as compared to 9 days in all other treatments. Among all essential oils, thymol at all concentrations maintained the overall quality of the pineapple and could potentially be used commercially in fresh fruit industries for longer storage.

Keywords: essential oils, antibrowning agents, antimicrobial agents, modified atmosphere packaging, microbial decay, pineapple

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Authors: Lingfeng Wang, Zhipeng Chen, Shuang Qiu, Shijian Ge

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The effects of wastewater, with four different nutrient loadings, from synthetic centrate on biomass production of Chlorella vulgaris, nutrient removal, microalgal settling, and lipid production were investigated in photobioreactors under both batches and, subsequently, semi-continuous operations. At higher centrate concentration factors (17.2% and 36.2%), hydraulic retention time and pH adjustments could be employed to sustain acceptable microalgal growth rates and wastewater treatment. Similar nutrient removals efficiencies (>95%) and biomass production (0.42-0.51 g/L) were observed for the four centrate concentrations. Both the lipid productivity and lipid content decreased with increasing nutrient loading in the wastewater. The results also demonstrated that the mass ratio of carbohydrate to protein could provide a good indication of microalgal settling performance, rather than sole component composition or total extracellular polymeric substances.

Keywords: lipid production, microalgae, nutrient removal, wastewater

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Authors: Ružica Tomičić, Zorica Tomičić, Peter Raspor

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An abundant growth of unwanted yeasts in food processing plants can lead to problems in quality and safety with significant financial losses. Candida and Pichia are the genera mainly involved in spoilage of products in the food and beverage industry. These contaminating microorganisms can form biofilms on food contact surfaces, being difficult to eradicate, increasing the probability of microbial survival and further dissemination during food processing. It is well known that biofilms are more resistant to antimicrobial agents compared to planktonic cells and this makes them difficult to eliminate. Among the strategies used to overcome resistance to antifungal drugs and preservatives, the use of natural substances such as plant extracts has shown particular promise, and many natural substances have been found to exhibit antifungal properties. This study aimed to investigated the impact of growth medium (Malt Extract broth (MEB) or Yeast Peptone Dextrose (YPD) broth) and temperatures (7°C, 37°C, 43°C for Candida strains and 7°C, 27°C, 32°C for Pichia strains) on the adhesion of Candida spp. and Pichia spp. to stainless steel (AISI 304) discs with different degrees of surface roughness (Ra = 25.20 – 961.9 nm), a material commonly used in the food industry. We also evaluated the antifungal and antiadhesion activity of plant extracts such as Humulus lupulus, Alpinia katsumadai and Evodia rutaecarpa against C. albicans, C glabrata and P. membranifaciens and investigated whether these plant extracts can interfere with biofilm formation. The adhesion was assessed by the crystal violet staining method, while the broth microdilution method CLSI M27-A3 was used to determine the minimum inhibitory concentration (MIC) of plant extracts. Our results indicated that the nutrient content of the medium significantly influenced the amount of adhered cells of the tested yeasts. The growth medium which resulted in a higher adhesion of C. albicans and C. glabrata was MEB, while for C. parapsilosis and C. krusei was YPD. In the case of P. pijperi and P. membranifaciens, YPD broth was more effective in promoting adhesion than MEB. Regarding the effect of temperature, C. albicans strain adhered to stainless steel surfaces in significantly higher level at a temperature of 43°C, while on the other hand C. glabrata, C. parapsilosis and C. krusei showed a different behavior with significantly higher adhesion at 37°C than at 7°C and 43°C. Further, the adherence ability of Pichia strains was highest at 27°C. Based on the MIC values, all plant extracts exerted significant antifungal effects with MIC values ranged from 100 to 400 μg/mL. It was observed that biofilm of C. glabrata were more resistance to plant extracts as compared to C. albicans. However, extracts of A. katsumadai and E. rutaecarpa promoted the growth and development of the preformed biofilm of P. membranifaciens. Thus, the knowledge of how these microorganisms adhere and which factors affect this phenomenon is of great importance in order to avoid their colonization on food contact surfaces.

Keywords: adhesion, Candida spp., Pichia spp., plant extracts

Procedia PDF Downloads 177

Authors: Xiao-Hua Zhu, Xin Yuan, Yi-Ran Zhao

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High-cadmium pollution in rice is a serious problem in many parts of China. Many kinds of remediation technologies have been tested and applied in many farmlands. Because of the productive function of the farmland, most technologies are inappropriate due to their destruction to the tillage soil layer. And the large labours and expensive fees of many technologies are also the restrictive factors for their applications. The conception of 'Root Micro-Geochemical Barrier' was proposed to reduce cadmium (Cd) bioavailability and the concentration of the cadmium in rice. Remediation and mitigation techniques were demonstrated on contaminated farmland in the downstream of some mine. According to the rule of rice growth, Cd would be absorbed by the crops in every growth stage, and the plant-absorb efficiency in the first stage of the tillering stage is almost the highest. We should create a method to protect the crops from heavy metal pollution, which could begin to work from the early growth stage. Many materials with repair property get our attention. The materials will create a barrier preventing Cd from being absorbed by the crops during all the growing process because the material has the ability to adsorb soil-Cd and making it losing its migration activity. And we should choose a good chance to put the materials into the crop-growing system cheaply as soon as early. Per plant, rice has a little root system scope, which makes the roots reach about 15cm deep and 15cm wide. So small root radiation area makes it possible for all the Cd approaching the roots to be adsorbed with a small amount of adsorbent. Mixing the remediation materials with the seed-raising soli and adding them to the tillage soil in the process of transplanting seedlings, we can control the soil-Cd activity in the range of roots to reduce the Cd-amount absorbed by the crops. Of course, the mineral materials must have enough adsorptive capacity and no additional pollution. More than 3000 square meters farmlands have been remediated. And on the application of root micro-geochemical barrier, the Cd-concentration in rice and the remediation-cost have been decreased by 90% and 80%, respectively, with little extra labour brought to the farmers. The Cd-concentrations in rice from remediated farmland have been controlled below 0.1 ppm. The remediation of one acre of contaminated cropland costs less than $100. The concept has its advantage in the remediation of paddy field contaminated by Cd, especially for the field with outside pollution sources.

Keywords: cadmium pollution, growth stage, cost, root micro-geochemistry barrier

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Authors: Padmanabhan D, Kavitha S

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The purpose of the study is to investigate arsenic resistance ability of indigenous microflora and its ability to utilize arsenic species form containing water source. PS-6 potential arsenic tolerance bacterium was screened from thirty isolates from Pichavaram Mangroves of India having tolerance to grow up to 1000 mg/l of As (V) and 800 mg/l of As (III) and arsenic utilization ability of 98 % of As (V) and 97% of As (III) with initial concentration of 3-5 mg/l within 48 hrs. Optimum pH and temperature was found to be ~7-7.4 and 37°C. Active growth of PS-6 in minimal salt media (MSB) helps in cost effective biomass production. Dry weight analysis of PS-6 has shown significant difference in biomass when exposed to As (III) and As (V). Protein level study of PS-6 after exposing to As (V) and As (III) shown modification in total protein concentration and variation in SDS-PAGE pattern. PS-6 was identified as Bacillus licheniformis based on partially sequenced of 16S rRNA using NCBI Blast. Further investigation will help in using this potential bacterium as a well-grounded source for urgency.

Keywords: arsenite, arsenate, Bacillus licheniformis, utilization

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Authors: Bryan D. Llenarizas, Maria Carla F. Manzano

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The rapid growth of electricity demand has led to a pursuit of alternative energy sources with high power output and not harmful to the environment. The fuel cell is a device that generates electricity via chemical reactions between the fuel and oxidant. Fuel cells have been known for decades, but the development of high-power output and durability was still one of the drawbacks of this energy source. This study investigates the potential of layer-by-layer composite for fuel cell applications. A two-electrode electrochemical cell was used for the galvanostatic electrochemical deposition method to fabricate a Polypyrrole/rGO|Polypyrrole/ZnO layer-by-layer composite material for fuel cell applications. In the synthesis, the first layer comprised 0.1M pyrrole monomer and 1mg of rGO, while the second layer had 0.1M pyrrole monomer and variations of ZnO concentration ranging from 0.08M up to 0.12M. A constant current density of 8mA/cm² was applied for 1 hour in fabricating each layer. Scanning electron microscopy (SEM) for the fabricated LBL material shows a globular surface with white spots. These white spots are the ZnO particles confirmed by energy-dispersive X-ray spectroscopy, indicating a successful deposition of the second layer onto the first layer. The observed surface morphology was consistent for each variation of ZnO concentrations. AC measurements were conducted to obtain the AC resistance of the fabricated film. Results show a decrease in AC resistance as the concentration of ZnO increases.

Keywords: anode, composite material, electropolymerization, fuel cell, galvanostatic, polypyrrole

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Authors: Jungkyun Na, Jaesang Lee, Yang Mo Koo

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In this study to find a replacement for expensive secondary recrystallization in GO electrical steel production, effect of heat treatment on the formation of columnar grain and Goss texture is investigated. The composition of the sample is Fe-2.0Si-0.2C. This process involves repeating of cold rolling and decarburization as a replacement for secondary recrystallization. By cold-rolling shear band is made and Goss grain grows from shear band by decarburization. By doing another cold rolling, some Goss texture is newly formed from the shear band, and some Goss texture is retained in microbands. To determine whether additional heat treatment with H2 atmosphere is needed on decarburization process for growth of Goss texture, comparing between decarburization and heat treatment with H2 atmosphere is performed. Also, to find optimum condition for heat treatment, heat treatment with various time and temperature is performed. It was found that increase in the number of cold rolling and heat treatment increases Goss texture. Both high Goss texture and good columnar structure is achieved at 900℃, and this temperature is within a+r phase region. Heat treatment at a temperature higher than a+r phase region caused carbon diffusion and this made layer with Goss grain decrease.

Keywords: electrical steel, Goss texture, columnar structure, normal grain growth

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Authors: Sean Taylor, Sayantani Neogi, Julia Budka

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The important Egyptian New Kingdom settlement at Sai Island Sudan presents a complex stratigraphic archaeological record. This study takes the theoretic stance that it, not just the archaeological material being retrieved from the deposits but the sediments themselves that reflect human agency. These anthropogenic sediments reflect the use life of the buildings and spaces between and the post-depositional processes which operate to complicate the archaeological record. The application of soil micromorphology is a technique that takes intact block samples of sediment and analyses them in thin section under a petrological microscope. A detailed understanding of site formation processes and a contextualized knowledge of the material culture can be understood through careful and systematic observation of the changing facies. The major findings of the study are that soil and sedimentary information can provide valuable insights to the use of space during the New Kingdom and elucidate the complexities of site formation processes.

Keywords: anthropogenic sediment, New Kingdom, site formation processes, soil micromorphology

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Authors: Debajyoti Choudhuri, Ratan Kumar Giri, Shesadev Pradhan

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The perturbed nonlinear Schrodinger equation involving the p-biharmonic and the p-Laplacian operators involving a real valued parameter and a continuous real valued potential function defined over the N- dimensional Euclidean space has been considered. By the variational technique, an existence result pertaining to a nontrivial solution to this non-linear partial differential equation has been proposed. Further, by the Concentration lemma, the concentration of solutions to the same problem defined on the set consisting of those elements where the potential function vanishes as the real parameter approaches to infinity has been addressed.

Keywords: p-Laplacian, p-biharmonic, elliptic PDEs, Concentration lemma, Sobolev space

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Authors: Hamid Khachab, Yamani Abdelkafi, Mouna Barhmi

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The epitaxial growth has great important in the fabricate of the new semi-conductors devices and upgrading many factors, such as the quality of crystallization and efficiency with their deferent types and the most effective epitaxial technique is the molecular beam epitaxial. The MBE growth modeling allows to confirm the experiments results out by atomic beam and to analyze the microscopic phenomena. In of our work, we determined the growth processes specially the ZnSe epitaxial technique by Kinetic Monte Carlo method and we also give observations that are made in real time at the growth temperature using reflection high energy electron diffraction (RHEED) and photoemission current.

Keywords: molecular beam epitaxy, II-VI, morpholy, photoemission, RHEED, simulation, kinetic Monte Carlo, ZnSe

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Authors: Deepti Kohli, Meeta Keswani Mehra

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The paper develops a theoretical model of electoral competition with purely opportunistic candidates and a uni-dimensional policy using the probability voting approach while focusing on the aspect of lobby formation to analyze the inherent complex interactions between centripetal and centrifugal forces and their effects on equilibrium policy platforms. There exist three types of agents, namely, Left-wing, Moderate and Right-wing who comprise of the total voting population. Also, it is assumed that the Left and Right agents are free to initiate a lobby of their choice. If initiated, these lobbies generate donations which in turn can be contributed to one (or both) electoral candidates in order to influence them to implement the lobby’s preferred policy. Four different lobby formation scenarios have been considered: no lobby formation, only Left, only Right and both Left and Right. The equilibrium policy platforms, amount of individual donations by agents to their respective lobbies and the contributions offered to the electoral candidates have been solved for under each of the above four cases. Since it is assumed that the agents cannot coordinate each other’s actions during the lobby formation stage, there exists a probability with which a lobby would be formed, which is also solved for in the model. The results indicate that the policy platforms of the two electoral candidates converge completely under the cases of no lobby and both (extreme) formations but diverge under the cases of only one (Left or Right) lobby formation. This is because in the case of no lobby being formed, only the centripetal forces (emerging from the election-winning aspect) are present while in the case of both extreme (Left-wing and Right-wing) lobbies being formed, centrifugal forces (emerging from the lobby formation aspect) also arise but cancel each other out, again resulting in a pure policy convergence phenomenon. In contrast, in case of only one lobby being formed, both centripetal and centrifugal forces interact strategically, leading the two electoral candidates to choose completely different policy platforms in equilibrium. Additionally, it is found that in equilibrium, while the donation by a specific agent type increases with the formation of both lobbies in comparison to when only one lobby is formed, the probability of implementation of the policy being advocated by that lobby group falls.

Keywords: electoral competition, equilibrium policy platforms, lobby formation, opportunistic candidates

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Authors: Mutaju Marobhe, Pastory Dickson

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This study explores the role of Foreign Direct Investment (FDI) in stimulating economic growth of emerging economies. FDIs have been associated with higher economic growth rates in developed countries due to the presence of conducive business conditions e.g. advanced financial markets which may accelerate the rate at which FDI boosts economic growth. So this study sets out to evaluate this macroeconomic phenomenon in emerging economies using the case study of Southern Africa Development Community (SADC) countries. The study uses Ease of Doing Business Index as a variable that moderates the relationship between FDI and economic growth. Panel data ranging from 2010 to 2019 from all SADC members are used and due to the unbalanced nature of the data, fixed effects regression analysis with moderation effect is used to assess this phenomenon. The conclusions and recommendations generated by this study will enable emerging economies to depict how they can be able to significantly improve FDI’s role in accelerating economic growth similarly to developed economies.

Keywords: ease of doing business, economic growth, emerging economies, foreign direct investment

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Authors: Henrique Alpalhão

Abstract:

This paper attempts to model the widely studied relationship between a country's economic growth and its level of democracy, with an emphasis on possible non-linearities. We adopt the concept of 'political capital' as a measure of democracy, which is extremely uncommon in the literature and brings considerable advantages both in terms of dynamic considerations and plausibility. While the literature is not consensual on this matter, we obtain, via panel Arellano-Bond regression analysis on a database of more than 60 countries over 50 years, significant and robust results that indicate that the impact of democratization on economic growth varies according to the stage of democratic development each country is in.

Keywords: democracy, economic growth, political capital, political economy

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Authors: Aderet M. Pantierer, Shmuel Pantierer, Raphael Cordina, Yougashwar Budhoo

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Stress concentration occurs when there is an abrupt change in geometry, a mechanical part under loading. These changes in geometry can include holes, notches, or cracks within the component. The modifications create larger stress within the part. This maximum stress is difficult to determine, as it is directly at the point of the minimum area. Strain gauges have yet to be developed to analyze stresses at such minute areas. Therefore, a stress concentration factor must be utilized. The stress concentration factor is a dimensionless parameter calculated solely on the geometry of a part. The factor is multiplied by the nominal, or average, stress of the component, which can be found analytically or experimentally. Stress concentration graphs exist for common loading conditions and geometrical configurations to aid in the determination of the maximum stress a part can withstand. These graphs were developed from historical data yielded from experimentation. This project seeks to verify a stress concentration graph for combined loading conditions. The aforementioned graph was developed using CATIA Finite Element Analysis software. The results of this analysis will be validated through further testing. The 3D modeled parts will be subjected to further finite element analysis using Patran-Nastran software. The finite element models will then be verified by testing physical specimen using a tensile testing machine. Once the data is validated, the unique stress concentration graph will be submitted for publication so it can aid engineers in future projects.

Keywords: stress concentration, finite element analysis, finite element models, combined loading

Procedia PDF Downloads 409