Search results for: high strain rate

Authors: Precious M. Tshabalala, Thula S. Dlamini, Frikkie Liebenberg, Johann Kirsten

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Numerous studies have been conducted, and the evidence has been unambiguous showing that investing in agricultural research and development increases productivity. Continued investments in agricultural research have led to the development of over 26 successful plum cultivars since 1980 at the Agricultural Research Council’s (ARC) Infruitec/Nietvoorbij in South Africa, and more continue to be developed to meet the specific needs of both producers and consumers. Yet very little is known about the returns on any of these research initiatives. The objective of the study was determine the economic impact of plum research investments at the ARC-the main plum breeding research organization in the country. The rate of return to plum research is estimated by estimating parameters in plum production and expressing research investment as an explanatory variable. The marginal rate of return is then determined to be 14.23 per cent. The rate of return to investment being this high is indicative of an under investment in plum research.

Keywords: Agricultural research investments, productivity and rate of return, plum

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Authors: Nikhil Padhye

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Recently a new phenomenon for bonding of polymeric films in solid-state, at ambient temperatures well below the glass transition temperature of the polymer, has been reported. This is achieved by bulk plastic compression of polymeric films held in contact. Here we analyze the process of cold-rolling of polymeric films via finite element simulations and illustrate a flexible and modular experimental rolling-apparatus that can achieve bonding of polymeric films through cold-rolling. Firstly, the classical theory of rolling a rigid-plastic thin-strip is utilized to estimate various deformation fields such as strain-rates, velocities, loads etc. in rolling the polymeric films at the specified feed-rates and desired levels of thickness-reduction(s). Predicted magnitudes of slow strain-rates, particularly at ambient temperatures during rolling, and moderate levels of plastic deformation (at which Bauschinger effect can be neglected for the particular class of polymeric materials studied here), greatly simplifies the task of material modeling and allows us to deploy a computationally efficient, yet accurate, finite deformation rate-independent elastic-plastic material behavior model (with inclusion of isotropic-hardening) for analyzing the rolling of these polymeric films. The interfacial behavior between the roller and polymer surfaces is modeled using Coulombic friction; consistent with the rate-independent behavior. The finite deformation elastic-plastic material behavior based on (i) the additive decomposition of stretching tensor (D = De + Dp, i.e. a hypoelastic formulation) with incrementally objective time integration and, (ii) multiplicative decomposition of deformation gradient (F = FeFp) into elastic and plastic parts, are programmed and carried out for cold-rolling within ABAQUS Explicit. Predictions from both the formulations, i.e., hypoelastic and multiplicative decomposition, exhibit a close match. We find that no specialized hyperlastic/visco-plastic model is required to describe the behavior of the blend of polymeric films, under the conditions described here, thereby speeding up the computation process .

Keywords: Polymer Plasticity, Bonding, Deformation Induced Mobility, Rolling

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Authors: Kai-Chee Loh, Jingxin Zhang, Yen-Wah Tong

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Hydrolysis and acidogenesis are the rate-controlling steps in an anaerobic digestion (AD) process. Considering that the optimum conditions for each stage can be diverse diverse, the development of a multi-stage AD system is likely to the AD efficiency through individual optimization. In this research, we developed a highly integrate three-stage anaerobic digester (HM3) to combine the advantages of dry AD and wet AD for anaerobic co-digestion of food waste and horse manure. The digester design comprised mainly of three chambers - high-solids hydrolysis, high-solids acidogenesis and wet methanogensis. Through comparing the treatment performance with other two control digesters, HM3 presented 11.2 ~22.7% higher methane yield. The improved methane yield was mainly attributed to the functionalized partitioning in the integrated digester, which significantly accelerated the solubilization of solid organic matters and the formation of organic acids, as well as ammonia in the high-solids hydrolytic and acidogenic stage respectively. Additionally, HM3 also showed the highest volatile solids reduction rate among the three digesters. Real-time PCR and pyrosequencing analysis indicated that the abundance and biodiversity of microorganisms including bacteria and archaea in HM3 was much higher than that in the control reactors.

Keywords: anaerobic digestion, high-solids, food waste and horse manure, microbial community

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Authors: Laredo Alcalá Elan Iñaky, Hernandez Castillo Daniel, Martinez Hernandez José Luis, Arredondo Valdes Roberto, Gonzalez Gallegos Esmeralda, Anguiano Cabello Julia Cecilia

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Plant hormones are a group of molecules that control different processes ranging from the growth and development of the plant until their response to biotic and abiotic stresses. In this study, the capacity of production of various phytohormones was evaluated from a strain of Botryodiplodia theobromae by liquid fermentation system using the modified Mierch medium added with a hydrolyzate compound of mead all in a reactor without agitation at 28 °C for 15 days. Quantification of the metabolites was performed using high performance liquid chromatography techniques. The results showed that a microbial broth with at least five different types of plant hormones was obtained: gibberellic acid, zeatin, kinetin, indoleacetic acid and jasmonic acid, the last one was higher than the others metabolites produced. The production of such hormones using a single type of microorganism could be in the future a great alternative to reduce production costs and similarly reduce the use of synthetic chemicals.

Keywords: biosystem, plant hormones, Botryodiplodia theobromae, fermentation

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Authors: Huma Balouch

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Menochilus sexmaculatus commonly known as six spotted zig zag ladybird, is an aphidophagus and the most misidentified Coccinellids due to the occurrence of numerous color variants. The correct identification of Menochilus sexmaculatus and its strains is necessary to implement the use of biological control. In the present study phenotypic and genotypic polymorphism was investigated in Menochilus sexmaculatus collected from Punjab, NWFP and Sindh provinces of Pakistan. Six different morphs of the species were distinguished by analyzing its Elytral color and spot pattern and then Polymerase Chain Reaction was used to generate random amplification of polymorphic DNA (RAPD) from six different types of Menochilus sexmaculatus. Forty primers (OPA & OPC Kit) were used to perform RAPD PCR on six different types of Menochilus sexmaculatus of which, seven primers revealed different patterns related to the Menochilus sexmaculatus types. These seven primers (OPA-04, OPA-09, OPA-18, OPC-04, OPC-12, OPC-15 and OPC-18) produced 111 clear polymorphic bands and 6 scorable strain specific markers. The cluster analysis applied to RAPD data showed high polymorphism among six types and it can be concluded that these six types are six polymorphic strains of the same species.

Keywords: Menochilus sexmaculatus, aphidophagus, coccinellids, phenotypic and genotypic polymorphism, RAPD-PCR, strain specific markers

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Authors: Emdad K. Z. Balanji, M. Neaz Sheikh, Muhammad N. S. Hadi

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This paper presents results of an experimental investigation on the behaviour of Hybrid Steel Fibre Reinforced High Strength Concrete (HSFR-HSC) cylinder specimens (150 mm x 300 mm) under uniaxial compression. Three different combinations of HSFR-HSC specimens and reference specimens without steel fibres were prepared. The first combination of HSFR-HSC included 1.5% Micro Steel (MS) fibre and 1% Deformed Steel (DS) fibre. The second combination included 1.5% MS fibre and 1.5% Hooked-end Steel (HS) fibre. The third combination included 1% DS fibre and 1.5% HS fibre. The experimental results showed that the addition of hybrid steel fibres improved the ductility of high strength concrete. The combination of MS fibre and HS fibre in high strength concrete mixes showed best stress-strain behaviour compared to the other combinations and the reference specimens.

Keywords: high strength concrete, micro steel fibre (MS), deformed steel fibre (DS), hooked-end steel fibre (HS), hybrid steel fibre

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Authors: Dongjoo Kim, Chang-Sik Son, Won-Seok Kang

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Adequate sleep affects various parts of one’s overall physical and mental life. As one of the methods in determining the appropriate amount of sleep, this research presents a heart rate based sleep quality index. In order to evaluate sleep quality using the heart rate, sleep data from 280 subjects taken over one month are used. Their sleep data are categorized by a three-part heart rate range. After categorizing, some features are extracted, and the statistical significances are verified for these features. The results show that some features of this sleep quality index model have statistical significance. Thus, this heart rate based sleep quality index may be a useful discriminator of sleep.

Keywords: sleep, sleep quality, heart rate, statistical analysis

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Authors: Sifriyani Sifriyani, I Nyoman Budiantara, Sri Haryatmi, Gunardi Gunardi

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East Java Province has a first rank as a province that has the most counties and cities in Indonesia and has the largest population. In 2015, the population reached 38.847.561 million, this figure showed a very high population growth. High population growth is feared to lead to increase the levels of unemployment. In this study, the researchers mapped and modeled the unemployment rate with 6 variables that were supposed to influence. Modeling was done by nonparametric geographically weighted regression methods with truncated spline approach. This method was chosen because spline method is a flexible method, these models tend to look for its own estimation. In this modeling, there were point knots, the point that showed the changes of data. The selection of the optimum point knots was done by selecting the most minimun value of Generalized Cross Validation (GCV). Based on the research, 6 variables were declared to affect the level of unemployment in eastern Java. They were the percentage of population that is educated above high school, the rate of economic growth, the population density, the investment ratio of total labor force, the regional minimum wage and the ratio of the number of big industry and medium scale industry from the work force. The nonparametric geographically weighted regression models with truncated spline approach had a coefficient of determination 98.95% and the value of MSE equal to 0.0047.

Keywords: East Java, nonparametric geographically weighted regression, spatial, spline approach, unemployed rate

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Authors: Sayaka Ono, Ryutaro Imai, Tomoko Ehara, Tetsuya Matsumoto, Hajime Matsumura

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Background: Wound pH affects a number of important factors in wound healing. We previously measured the pH value of the exudates collected from second-degree burns and found that the increase in pH was observed in the burn wounds in which colonized by Staphylococcus spp., and the increase in pH was evident prior to the clinical findings of local infection. To investigate the relationship between the changes of pH value and bacterial growth, we performed in vitro study using Pseudomonas aeruginosa and liquid medium as a locally infected wound equivalent model. Methods: Pseudomonas aeruginosa standard strain (ATCCR 10145TM) was cultured at 37 °C environment in Luria Broth Miller medium. The absorbance rate which means the amount of bacteria was measured by a microplate reader 2300EnSpireTM). The pH was measured using pH-indicator strips (MColorpHastTM). The statistical analysis was performed using the product-moment correlation coefficient of Pearson's. Results: The absorbance rate and pH value were increased along with culture period. There was a positive correlation between pH value and absorbance rate (n = 27, Pearson's r = 0.985). Moreover, there was a positive correlation between pH value and the culture period (n = 18, Pearson's r = 0.901). The bacteria was well growth in the media from pH 6.6 to pH 8.0 and the pH of culture media converged at 8 -9 along with the bacterial growth. Conclusion: From these results, we conclude that pH value of the wound is correlated with the number of viable bacteria and bacterial growth periods.

Keywords: colonization, potential of hydrogen, Pseudomonas aeruginosa, wound

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Authors: Y. Madani, H. Achache, B. Boutabout

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The purpose of this paper is to analyze numerically by the three-dimensional finite element method, using ABAQUS calculation code, the mechanical behavior of a unidirectional and multidirectional delaminated stratified composite under mechanical loading in Mode II. This study consists of the determination of the energy release rate G in mode II as well as the distribution of equivalent von Mises stresses along the damaged zone by varying several parameters such as the applied load and the delamination length. It allowed us to deduce that the high energy release rate favors delamination at the free edges of a stratified plate subjected to bending.

Keywords: delamination, energy release rate, finite element method, stratified composite

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Authors: Daniel O'Shea, Mario M. Attard, David C. Kellermann

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In this paper, we propose a hyperelastic strain energy function that maps isotopic hyperelastic constitutive laws for the use of orthotropic materials without the use of structural tensors or any kind of fiber vector, or the use of standard invariants. In particular, we focus on neo-Hookean class of models and represent them using an invariant-free formulation. To achieve this, we revise the invariant-free formulation of isotropic hyperelasticity. The formulation uses quadruple contractions between fourth-order tensors, rather than scalar products of scalar invariants. We also propose a new decomposition of the orthotropic Hookean stiffness tensor into two fourth-order Lamé tensors that collapse down to the classic Lamé parameters for isotropic continua. The resulting orthotropic hyperelastic model naturally maintains all of the advanced properties of the isotropic counterparts, and similarly collapse back down to their isotropic form by nothing more than equality of parameters in all directions (isotropy). Comparisons are made with large strain experimental results for transversely isotropic rubber type materials under tension.

Keywords: finite strain, hyperelastic, invariants, orthotropic

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Authors: Simin Asadollahi, Amir H. Soruri, Ali Moghimi

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Nowadays, salad oils are used in many countries around the world. Therefore, it is of great importance to ensure the safety of these food products which are usually packaged in Polyethylene terephthalate (PET) bottles and come on the market. This study investigated the effects of storage time and temperature on the migration rate of phthalate compounds from PET bottle to salad oil. In more detail, migration rate of bis (2-ethylhexyl) phthalate from bottles to salad oil samples was measured in 1st, the 30th, and the 60th days of storage at a temperature of either 20 or 40 °C. At both storage temperatures, an increase in the storage time led to a statistically significant increase in the migration rate of phthalate compounds (p<.01). Regarding this, the highest migration rate occurred after 60 days of storage in to the samples. Furthermore, it was revealed bis (2-ethylhexyl) phthalate had a higher migration rate at 40 °C than at 20 °C which showed that an increase in the storage temperature would lead to an increase in the migration rate. The highest migration rate occurred in relation to salad oil stored at 40 °C and after 60 days of storage.

Keywords: salad oil, migration rate, polyethylene terephthalate, bis (2-ethylhexyl) phthalate

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Authors: M. Palizvan, M. H. Sadr, M. T. Abadi

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The representative volume element (RVE) plays a central role in the mechanics of random heterogeneous materials with a view to predicting their effective properties. In this paper, a computational homogenization methodology, developed to determine effective linear elastic properties of composite materials, is extended to predict the effective nonlinear elastoplastic response of long fiber reinforced composite. Finite element simulations of volumes of different sizes and fiber volume fractures are performed for calculation of the overall response RVE. The dependencies of the overall stress-strain curves on the number of fibers inside the RVE are studied in the 2D cases. Volume averaged stress-strain responses are generated from RVEs and compared with the finite element calculations available in the literature at moderate and high fiber volume fractions. For these materials, the existence of an RVE is demonstrated for the sizes of RVE corresponding to 10–100 times the diameter of the fibers. In addition, the response of small size RVE is found anisotropic, whereas the average of all large ones leads to recover the isotropic material properties.

Keywords: homogenization, periodic boundary condition, elastoplastic properties, RVE

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Authors: M. Koray Cetin, Mehmet Mert

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The purpose of the study is to examine impacts on tourism revenues of the exchange rate and country overall security level. There are numerous studies that examine the bidirectional relation between macroeconomic factors and tourism revenues and tourism demand. Most of the studies support the existence of impact of tourism revenues on growth rate but not vice versa. Few studies examine the impact of factors like real exchange rate or purchasing power parity on the tourism revenues. In this context, firstly impact of real exchange rate on tourism revenues examination is aimed. Because exchange rate is one of the main determinants of international tourism services price in guests currency unit. Another determinant of tourism demand for a country is country’s overall security level. This issue can be handled in the context of the relationship between tourism revenues and overall security including turmoil, terrorism, border problem, political violence. In this study, factors are handled for several countries which have tourism revenues on a certain level. With this structure, it is a panel data, and it is evaluated with panel data analysis techniques. Panel data have at least two dimensions, and one of them is time dimensions. The panel data analysis techniques are applied to data gathered from Worldbank data web page. In this study, it is expected to find impacts of real exchange rate and security factors on tourism revenues for the countries that have noteworthy tourism revenues.

Keywords: exchange rate, panel data analysis, security, tourism revenues

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Authors: Zorica Tomičić, Ružica Tomičić, Peter Raspor

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Growing resistance of pathogenic yeast Candida glabrata to many classes of antifungal drugs has stimulated efforts to discover new agents to combat a rising number of invasive C. glabrata infections, which deserves a great deal of concern due to the high mortality rate in immunocompromised populations. One promising strategy is the use of probiotic microorganisms, which, when administered in adequate amounts, confers a health benefit. A selected number of probiotic organisms, Saccharomyces boulardii among them, have been tested as potential biotherapeutic agents. The aim of this study was to investigate the effect of the probiotic yeast S. boulardii on the adhesion of clinical isolates of C. glabrata at different temperatures, pH values, and in the presence of three clinically important antifungal drugs, such as fluconazole, itraconazole and amphotericin B. The method used to assess adhesion was crystal violet staining. The selection of antimycotics concentrations used in the adhesion assay was based on minimum inhibitory concentrations (MICs) obtained by the preliminarily performed microdilution modification of the Reference method for broth dilution antifungal susceptibility testing of yeast (Clinical and Laboratory Standards Institute (CLSI), standard M27-A2). the results showed that despite the nonadhesiveness of S. boulardii cells, probiotic yeast significantly suppressed the adhesion of C. glabrata strains. Besides, at specific strain ratios, a slight stimulatory effect was observed in some C. glabrata strains, which highlights the importance of strain specificity and opens up further research interests. When environmental conditions are considered, temperature and pH significantly influenced co-culture adhesion of C. glabrata and S. boulardii. The adhesion of C. glabrata strains was relatively equally reduced over all tested temperature range (28°C, 37°C, 39°C and 42°C) in the presence of S. boulardii cells, while the adhesion of a few C. glabrata strains were significantly stimulated at 28°C and suppressed at 42°C. Further, the adhesion was highly dependent on pH, with the highest adherence at pH 4 and lowest at pH 8.5. It was observed that S. boulardii did not manage to suppress the adhesion of C. glabrata strains at high pH. Antimycotics on the other hand showed a greater impact, since S. boulardii failed to affect co-culture adhesion at higher antimycotics concentrations. As expected, exposure to various concentrations of amphotericin B significantly reduced the adherence ability of C.glabrata strains both in a single culture and co-culture with S. boulardii. Therefore, it can be speculated that S. boulardii could substitute the effect of antimycotics in a range concentrations and with specific type of strains. This would certainly change the view on the treatment of yeast infections in the future.

Keywords: adhesion, antimycotics, candida glabrata, saccharomyces boulardii

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Authors: Kashif Ahmed

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Recent years researchers have been motivated towards extensive exploring of living organism, which could be utilized effectively in intense industrial conditions. The present study shows enhanced production, purification and characterization of industrial enzyme, invertase (Beta-D-fructofuranosidase) from Penicillium lilacinum. Various agricultural based by-products (cotton stalk, sunflower waste, rice husk, molasses and date syrup) were used as energy source. The highest amount of enzyme (13.05 Units/mL) was produced when the strain was cultured on growth medium containing date syrup as energy source. Yeast extract was used as nitrogen source after 96 h of incubation at incubation temperature of 40º C. Initial pH of medium was 8.0, inoculum size 6x10⁶ conidia and 200 rev/min agitation rate. The enzyme was also purified (7 folds than crude) and characterized. Molecular mass of purified enzyme (65 kDa) was determined by 10 % SDS-PAGE. Lineweaver-Burk Plot was used to determine Kinetic constants (Vmax 178.6 U/mL/min and Km 2.76 mM). Temperature and pH optima were 55º C and 5.5 respectively. MnCl₂ (52.9 %), MgSO₄ (48.9 %), BaCl₂ (24.6 %), MgCl₂ (9.6 %), CoCl₂ (5.7 %) and NaCl (4.2 %) enhanced the relative activity of enzyme and HgCl₂ (-92.8 %), CuSO₄ (-80.2 %) and CuCl₂ (-76.6 %) were proved inhibitors. The strain was showing enzyme activity even at extreme conditions of temperature (up to 60º C) and pH (up to 9), so it can be used in industries.

Keywords: invertase, Penicillium lilacinum, submerged fermentation, industrial enzyme

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Authors: Sahar Mobeen, Anam Rafique, Irum Baig

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Acoustic echo cancellation in multichannel is a system identification application. In real time environment, signal changes very rapidly which required adaptive algorithms such as Least Mean Square (LMS), Leaky Least Mean Square (LLMS), Normalized Least Mean square (NLMS) and average (AFA) having high convergence rate and stable. LMS and NLMS are widely used adaptive algorithm due to less computational complexity and AFA used of its high convergence rate. This research is based on comparison of acoustic echo (generated in a room) cancellation thorough LMS, LLMS, NLMS, AFA and newly proposed average normalized leaky least mean square (ANLLMS) adaptive filters.

Keywords: LMS, LLMS, NLMS, AFA, ANLLMS

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Authors: Kevin Mark Banks, Dannis Rorisang Nkarapa Maubane, Carel Coetzee

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The influence of aluminium content, reheating temperature, and sizing (final) strain on the as-rolled microstructure was systematically investigated in vanadium-microalloyed and C-Mn plate steels. Reheating, followed by hot rolling and air cooling simulations were performed on steels containing a range of aluminium and nitrogen contents. Natural air cooling profiles, corresponding to 6 and 20mm thick plates, were applied. The austenite and ferrite/pearlite microstructures were examined using light optical microscopy. Precipitate species and volume fraction were determined on selected specimens. No influence of aluminium content was found below 0.08% on the as-rolled grain size in all steels studied. A low Al-V-steel produced the coarsest initial austenite grain size due to AlN dissolution at low temperatures leading to abnormal grain growth. An Al-free V-N steel had the finest initial microstructure. Although the as-rolled grain size for 20mm plate was similar in all steels tested, the grain distribution was relatively mixed. The final grain size in 6mm plate was similar for most compositions; the exception was an as-cast V low N steel, where the size of the second phase was inversely proportional to the sizing strain. This was attributed to both segregation and a low VN volume fraction available for effective pinning of austenite grain boundaries during cooling. Increasing the sizing strain refined the microstructure significantly in all steels.

Keywords: aluminium, grain size, nitrogen, reheating, sizing strain, steel, vanadium

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Authors: Mohammad O. Diab, Sahera A. Saleh, Mustapha M. Dichari, Nijez Aloulou, Omar Hamoui, Feras Chehade

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This study sought to evaluate the efficiency of lead-free sterile radiation shield (Radionex) in the reduction of physician's exposure dose during interventional cardiology procedures. Cardiac catheterization procedures are often associated with high radiation doses and high levels of secondary radiation emitted by the patient's body. This study compares physician exposure dose rate during cardiac catheterization procedures done through the femoral artery with sterile radiation shielding to same procedures made without the shielding. The mean operator radiation dose rate without using the shield was found to be 18.4µSv/min compared to a mean dose rate of 5.1 µSv/min when using the shield, rendering a reduction of 72.5% of radiation received by the physician. Sterile radiation shielding is consequently an effective addition to a cardiac catheterization lab radiation protection system.

Keywords: cardiac catheterization, physician exposure dose, sterile radiation shielding, lead-free sterile radiation shields

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Authors: G. Ultanbekova, Zh. Suleimenova, Zh. Rakhmetova, G. Mombekova, S. Mantieva

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Plant Growth Promoting Rhizobacteria (PGPR) are a group of free-living bacteria that colonize the rhizosphere, enhance plant growth of many cereals and other important agricultural crops and protect plants from disease and abiotic stresses through a wide variety of mechanisms. The use of PGPR has been proven to be an environmentally sound way of increasing crop yields by facilitating plant growth. In the present study, strain improvement of PGPR isolates were carried out by chemical mutagenesis for the improvement of growth and yield of lima bean. Induced mutagenesis is widely used for the selection of microorganisms producing biologically active substances and further improving their activities. Strain improvement is usually done by classical mutagenesis which involves exposing the microbes to chemical or physical mutagens. The strains of Pseudomonas putida 4/1, Azotobacter chroococcum Р-29 and Bacillus subtilis were subjected to mutation process for strain improvement by treatment with a chemical agent (sodium nitrite) to cause mutation and were observed for its consequent action on the seeds germination and plant growth of lima bean (Phaseolus lunatus). Bacterial mutant strains of Pseudomonas putida M-1, Azotobacter chroococcum M-1 and Bacillus subtilis M-1, treated with sodium nitrite in the concentration of 5 mg/ml for 120 min, were found effective to enhance the germination of lima bean seeds compared to parent strains. Moreover, treatment of the lima bean seeds with a mutant strain of Bacillus subtilis M-1 had a significant stimulation effect on plant growth. The length of the stems and roots of lima bean treated with Bacillus subtilis M-1 increased significantly in comparison with parent strain in 1.6 and 1.3 times, respectively.

Keywords: chemical mutagenesis, germination, kidney bean, plant growth promoting rhizobacteria (PGPR)

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Authors: Priya Tomar, Pallavi Mittal

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Bioremediation has been recognized as an environment friendly and less expensive method which involves the natural processes resulting in the efficient conversion of hazardous compounds into innocuous products. The pulp and paper mill effluent is one of the high polluting effluents amongst the effluents obtained from polluting industries. The colouring body present in the wastewater from pulp and paper mill is organic in nature and is comprised of wood extractives, tannin, resins, synthetic dyes, lignin, and its degradation products formed by the action of chlorine on lignin which imparts an offensive colour to the water. These mills use different chemical process for paper manufacturing due to which lignified chemicals are released into the environment. Therefore, the chemical oxygen demand (COD) of the emanating stream is quite high. For solving the above problem we present this paper with some new techniques that were developed for the efficiency of paper mill effluents. In the present study we utilized the consortia of fungal and bacterial strain and the treatment named as C1, C2, and C3 for the decolourization of paper mill effluent. During the study, role of carbon source i.e. glucose was studied for decolourization. From the results it was observed that a maximum colour reduction of 66.9%, COD reduction of 51.8%, TSS reduction of 0.34%, TDS reduction of 0.29% and pH changes of 4.2 is achieved by consortia of Aspergillus niger with Pseudomonas aeruginosa. Data indicated that consortia of Aspergillus niger with Pseudomonas aeruginosa is giving better result with glucose.

Keywords: bioremediation, decolourization, black liquor, mycoremediation

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Authors: Abdalrahman D. Alsulaili, Sheikha Y. Aljeraiwi, Athba N. Almanaie, Raghad Y. Alhajeri, Mariam Z. Almijren

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The water accompanying oil in the oil production process is increasing and due to its increasing rates a problem with handling it occurred. Current solutions like discharging into the environment, dumping water in evaporation pits, usage in the industry and reinjection in oil reservoirs to enhance oil production are used worldwide. The water injection method has been introduced to the oil industry with a process that either immediately injects water to the reservoir or goes to the filtration process before injection all depending on the porosity of the soil. Reinjection of unfiltered effluent water with high Total Suspended Solid (TSS) and Oil in Water (O/W) into soils with low porosity cause a blockage of pores, whereas soils with high porosity do not need high water quality. Our study mainly talks about the filtration and adsorption of the water using organic media as the adsorbent. An adsorbent is a substance that has the ability to physically hold another substance in its surface. Studies were done on nutshell and date pits with different surface areas and flow rates by using a 10inch filter connected with three tanks to perform as one system for the filtration process. Our approach in the filtration process using different types of medias went as follow: starting first with crushed nutshell, second with ground nutshell, and third using carbonized date pits with medium flow rate then high flow rate to compare different results. The result came out nearly as expected from our study where both O/W and TSS were reduced from our oily water sample by using this organic material. The effect of specific area was noticed when using nutshell as the filter media, where the crushed nutshell gave us better results than ground nutshell. The effect of flow rate was noticed when using carbonized date pits as the filter media whereas the treated water became more acceptable when the flow rate was on the medium level.

Keywords: date pits, nutshell, oil water, TSS

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Authors: Ahmed F. Azmy, Amal E. Saafan, Tamer M. Essam, Magdy A. Amin, Shaban H. Ahmed

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Bacterial strains capable of degradation of malathion from the domestic sewage were isolated by an enrichment culture technique. Three bacterial strains were screened and identified as Acinetobacter baumannii (AFA), Pseudomonas aeruginosae (PS1),andPseudomonas mendocina (PS2) based on morphological, biochemical identification and 16S rRNA sequence analysis. Acinetobacter baumannii AFA was the most efficient malathion degrading bacterium, so used for further biodegradation study. AFA was able to grow in mineral salt medium (MSM) supplemented with malathion (100 mg/l) as a sole carbon source, and within 14 days, 84% of the initial dose was degraded by the isolate measured by high performance liquid chromatography. Strain AFA could also degrade other organophosphorus compounds including diazenon, chlorpyrifos and fenitrothion. The effect of different culture conditions on the degradation of malathion like inoculum density, other carbon or nitrogen sources, temperature and shaking were examined. Degradation of malathion and bacterial cell growth were accelerated when culture media were supplemented with yeast extract, glucose and citrate. The optimum conditions for malathion degradation by strain AFA were; an inoculum density of 1.5x 1012CFU/ml at 30°C with shaking. A specific polymerase chain reaction primers were designed manually using multiple sequence alignment of the corresponding carboxylesterase enzymes of Acinetobacter species. Sequencing result of amplified PCR product and phylogenetic analysis showed low degree of homology with the other carboxylesterase enzymes of Acinetobacter strains, so we suggested that this enzyme is a novel esterase enzyme. Isolated bacterial strains may have potential role for use in bioremediation of malathion contaminated.

Keywords: Acinetobacter baumannii, biodegradation, malathion, organophosphate pesticides

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Authors: Chiedza Z. Tsvakirai, Precious M. Tshabalala, Frikkie Liebenberg, Johann F. Kirsten

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Agricultural research conducted by the Agricultural Research Council has played an important role in increasing the productivity and profitability of the South African peach and nectarine industry. However, the importance of this research remains unclear to the industry stakeholders because a rate of return for this research has never been done. As a result, funding for the research at Agricultural Research Council has been waning because it is not clear how much value has been created and how much the industry stands to gain with continued research investment. Therefore, this study seeks to calculate the benefit of research investments in a bid to motivate for an increase in funding. The study utilized the supply response function to do this. The rate of return calculation revealed that agricultural research had a marginal internal rate of return of 55.9%. This means that every R1 invested yields a 56 c increase in value in the industry. Being this high, it can be concluded that investment in agricultural research is worthwhile. Thus justifies for an increase in research funding.

Keywords: Benefits of research investment, productivity.

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Authors: Jonathan Olusegun Famoroti, Mathew Ekundayo Rotimi, Mishelle Doorasamy

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This study offers an empirical investigation into some selected macroeconomic drivers of the monetary policy rate in member countries of the West African Monetary Zone (WAMZ), considering both internal and external variables. We employed Autoregressive Distributed Lag (ARDL) to carry out the investigation between monetary policy and some macroeconomic variables in both the long-run and short-run relationship. The results suggest that the drivers of the policy rate in this zone, in the long run, include, among others, global oil price, exchange rate, inflation rate, and gross domestic product, while in the short run, federal fund rate, trade openness, exchange rate, inflation rate, and gross domestic product are core determinants of the policy rate. Therefore, in order to ensure long-run stability in the policy rate among the members’ states, these drivers should be given closer consideration so that the trajectory for effective structure can be designed and fused into the economic structure and policy frameworks accordingly.

Keywords: monetary policy rate, macroeconomic variables, WAMZ, ARDL

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Authors: Gulcan Ozerim, Gunay Anlas

Abstract:

In shape memory alloys, upon loading, stress increases around crack tip and a martensitic phase transformation occurs in early stages. In many studies the stress distribution in the vicinity of the crack tip is represented by using linear elastic fracture mechanics (LEFM) although the pseudo-elastic behavior results in a nonlinear stress-strain relation. In this study, the HRR singularity (Hutchinson, Rice and Rosengren), that uses Rice’s path independent J-integral, is tried to formulate the stress distribution around the crack tip. In HRR approach, the Ramberg-Osgood model for the stress-strain relation of power-law hardening materials is used to represent the elastic-plastic behavior. Although it is recoverable, the inelastic portion of the deformation in martensitic transformation (up to the end of transformation) resembles to that of plastic deformation. To determine the constants of the Ramberg-Osgood equation, the material’s response is simulated in ABAQUS using a UMAT based on ZM (Zaki-Moumni) thermo-mechanically coupled model, and the stress-strain curve of the material is plotted. An edge cracked shape memory alloy (Nitinol) plate is loaded quasi-statically under mode I and modeled using ABAQUS; the opening stress values ahead of the cracked tip are calculated. The stresses are also evaluated using the asymptotic equations of both LEFM and HRR. The results show that in the transformation zone around the crack tip, the stress values are much better represented when the HRR singularity is used although the J-integral does not show path independent behavior. For the nodes very close to the crack tip, the HRR singularity is not valid due to the non-proportional loading effect and high-stress values that go beyond the transformation finish stress.

Keywords: crack, HRR singularity, shape memory alloys, stress distribution

Procedia PDF Downloads 316

Authors: Y.J. Wang, C. Q. Ru

Abstract:

A key issue of cohesive zone models is how to determine the cohesive zone model parameters based on real material test data. In this paper, uniaxial nominal stress-strain curve (SS curve) is used to determine two key parameters of a cohesive zone model (CZM): The maximum traction and the area under the curve of traction-separation law (TSL). To this end, the true SS curve is obtained based on the nominal SS curve, and the relationship between the nominal SS curve and TSL is derived based on an assumption that the stress for cracking should be the same in both CZM and the real material. In particular, the true SS curve after necking is derived from the nominal SS curve by taking the average of the power law extrapolation and the linear extrapolation, and a damage factor is introduced to offset the true stress reduction caused by the voids generated at the necking zone. The maximum traction of the TSL is equal to the maximum true stress calculated based on the damage factor at the end of hardening. In addition, a simple specimen is modeled by Abaqus/Standard to calculate the critical J-integral, and the fracture energy calculated by the critical J-integral represents the stored strain energy in the necking zone calculated by the true SS curve. Finally, the CZM parameters obtained by the present method are compared to those used in a previous related work for a simulation of the drop-weight tear test.

Keywords: dynamic fracture, cohesive zone model, traction-separation law, stress-strain curve, J-integral

Procedia PDF Downloads 459

Authors: Polo G. Yohn Edison, Rocha F. Pedricto

Abstract:

This work presents a study about a retaining structure designed for the duplication of the rail FEPASA on the 74th km between Santos and São Paulo. This structure, an anchored retaining wall, was instrumented in the anchors heads with strain gauges in order to monitor its loads. The load measurements occurred during the performance test, locking and also after the works were concluded. A decrease on anchors loads is noticed at the moment immediately after the locking, during construction and after the works finished. It was observed that a loss of load in the anchors occurred to a maximum of 54%.

Keywords: instrumentation, strain gauges, retaining wall, anchors

Procedia PDF Downloads 476

Authors: Swati Swati, Yuhang Chen, Robert Reuben

Abstract:

Coronary stents are devices resembling the shape of a tube which are placed in coronary arteries, to keep the arteries open in the treatment of coronary arterial diseases. Coronary stents are routinely deployed to clear atheromatous plaque. The stent essentially applies an internal pressure to the artery because its structure is cylindrically symmetrical and this may introduce some abnormalities in final arterial shape. The goal of the project is to develop segmented circumferential arterial compliance measuring devices which can be deployed (eventually) in vivo. The segmentation of the device will allow the mechanical asymmetry of any stenosis to be assessed. The purpose will be to assess the quality of arterial tissue for applications in tailored stents and in the assessment of aortic aneurism. Arterial distensibility measurement is of utmost importance to diagnose cardiovascular diseases and for prediction of future cardiac events or coronary artery diseases. In order to arrive at some generic outcomes, a preliminary experimental set-up has been devised to establish the measurement principles for the device at macro-scale. The measurement methodology consists of a strain gauge system monitored by LABVIEW software in a real-time fashion. This virtual instrument employs a balloon within a gelatine model contained in a split cylinder with strain gauges fixed on it. The instrument allows automated measurement of the effect of air-pressure on gelatine and measurement of strain with respect to time and pressure during inflation. Compliance simple creep model has been applied to the results for the purpose of extracting some measures of arterial compliance. The results obtained from the experiments have been used to study the effect of air pressure on strain at varying time intervals. The results clearly demonstrate that with decrease in arterial volume and increase in arterial pressure, arterial strain increases thereby decreasing the arterial compliance. The measurement system could lead to development of portable, inexpensive and small equipment and could prove to be an efficient automated compliance measurement device.

Keywords: arterial compliance, atheromatous plaque, mechanical symmetry, strain measurement

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Authors: Goutam Dubey, Varun Dutta

Abstract:

In the present study, rotary-electro discharge machining of EN31 tool steel has been carried out using a pure copper electrode. Various response variables such as Material Removal Rate (MRR), Tool Wear Rate (TWR), and Machining Rate (MR) have been studied against the selected process variables. The selected process variables were peak current (I), voltage (V), duty cycle, and electrode rotation (N). EN31 Tool Steel is hardened, high carbon steel which increases its hardness and reduces its machinability. Reduced machinability means it not economical to use conventional methods to machine EN31 Tool Steel. So, non-conventional methods play an important role in machining of such materials.

Keywords: electric discharge machining, EDM, tool steel, tool wear rate, optimization techniques

Procedia PDF Downloads 190