Search results for: coupled BEM-FEM

Authors: N. Hedayat, E. Karamifar

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Sustainable food and fiber production is emerging as an irresistible option in agrarian planning. Although one should not underestimate the successes of the Green Revolution in enhancing crop production, its adverse environmental and ecosystem consequences have also been remarkable. The aim of this paper is to identify ways of improving crop production to ensure agricultural sustainability and environmental integrity. Systematic observations are used for data collection on intensive farming, deforestation and the environmental implications of industrial pollutants on agricultural sustainability at national and international levels. These were achieved within a comparative analytical model of data interpretation. Results show that while multiple factors enhance yield, they have a simultaneous effect in undermining the ecosystem and environmental integrity. Results show that application of excessive agrichemical have been one of the major cause of polluting the surface and underground water bodies as well as soil layers in affected croplands. Results consider rapid deforestation in the tropical regions has been the underlying cause of impairing the integrity of biodiversity and oxygen-generation regime. These, coupled with production of greenhouse gasses, have contributed to global warming and hydrological irregularities. Continuous production of pollutants and effluents has affected marine and land biodiversity arising from acid rains generated by modern farming and deforestation. Continuous production of greenhouse gases has also been instrumental in affecting climatic behavior manifested in recurring draughts and contraction of lakes and ponds as well as emergence of potential flooding of waterways and floodplains in the future.

Keywords: agricultural sustainability, environmental integrity, pollution, eco-system

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Authors: Tej Varma Y, Debi D. Pant

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Photophysics and rotational dynamics of the fluorescent probe, 6-methoxyquinoline (6MQ) with cationic surfactant, alkyltrimethylammonium bromide (nTAB) micelle solutions have been investigated (n = 12, 14 and 16). Absorption and emission peaks of the dye have been observed to shift at concentrations around critical micellar concentration (cmc) of nTAB compared to that of bulk solutions suggesting probe is in a lower polar environment. The probe senses changes in polarity (ET (30)) brought about by variation of surfactant chain length concentration and is invariably solubilized in the aqueous interface or palisade layer. The order of change in polarity observed was DTAB > CTAB > TTAB. The binding constant study shows that the probe binds strongest with TTAB (is of the order TTAB > CTAB > DTAB) due to deeper penetration into the micelle. The anisotropy decay for the probe in all the nTAB micelles studied have been rationalized based on a two-step model consisting of fast-restricted rotation of the probe and slow lateral diffusion of the probe in the micelle that is coupled to the overall rotation of the micelle. Fluorescence lifetime measurements of probe in the cationic micelles demonstrate the close proximity of the 6MQ to the Br - counterions. The fluorescence lifetimes of TTAB and DTAB are much shorter than in CTAB. These results indicate that 6MQ resides to a substantial degree in the head group region of the micelles. All the changes observed in the steady state fluorescence, microenvironment, fluorescence lifetimes, fluorescence anisotropy, and other calculations are in agreement with each other suggesting binding of the cationic surfactant with the neutral dye molecule.

Keywords: photophysics, chain length, ntaB, micelles

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Authors: Claudius Peter Van Wyk

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Given the increasingly manifest phenomena, as described in complexity theory, of volatility, uncertainty, complexity and ambiguity (VUCA), Taleb's notion of 'antifragility, has a significant contribution to make to positive psychology applied to wellbeing. Antifragility is argued to be fundamentally different from the concepts of resiliency; as the ability to recover from failure, and robustness; as the ability to resist failure. Rather it describes the capacity to reorganise in the face of stress in such a way as to cope more effectively with systemic challenges. The concept, which has been applied in disciplines ranging from physics, molecular biology, planning, engineering, and computer science, can now be considered for its application in individual human and social wellbeing. There are strong correlations to Antonovsky's model of 'salutogenesis' in which an attitude and competencies are developed of transforming burdening factors into greater resourcefulness. We demonstrate, from the perspective of neuroscience, how technology measuring nervous system coherence can be coupled to acquired psychodynamic approaches to not only identify contextual stressors, utilise biofeedback instruments for facilitating greater coherence, but apply these insights to specific life stressors that compromise well-being. Employing an on-going case study with BMW South Africa, the neurological mapping is demonstrated together with 'reframing' and emotional anchoring techniques from neurolinguistic programming. The argument is contextualised in the discipline of psychoneuroimmunology which describes the stress pathways from the CNS and endocrine systems and their impact on immune function and the capacity to restore homeostasis.

Keywords: antifragility, complexity, neuroscience, psychoneuroimmunology, salutogenesis, volatility

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Authors: Tarek Abdoun, Ricardo Dobry

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This paper is a systematic effort to clarify why field liquefaction charts based on Seed and Idriss’ Simplified Procedure work so well. This is a necessary step toward integrating the states of the art (SOA) and practice (SOP) for evaluating liquefaction and its effects. The SOA relies mostly on laboratory measurements and correlations with void ratio and relative density of the sand. The SOP is based on field measurements of penetration resistance and shear wave velocity coupled with empirical or semi-empirical correlations. This gap slows down further progress in both SOP and SOA. The paper accomplishes its objective through: a literature review of relevant aspects of the SOA including factors influencing threshold shear strain and pore pressure buildup during cyclic strain-controlled tests; a discussion of factors influencing field penetration resistance and shear wave velocity; and a discussion of the meaning of the curves in the liquefaction charts separating liquefaction from no liquefaction, helped by recent full-scale and centrifuge results. It is concluded that the charts are curves of constant cyclic strain at the lower end (Vs1 < 160 m/s), with this strain being about 0.03 to 0.05% for earthquake magnitude, Mw ≈ 7. It is also concluded, in a more speculative way, that the curves at the upper end probably correspond to a variable increasing cyclic strain and Ko, with this upper end controlled by over consolidated and preshaken sands, and with cyclic strains needed to cause liquefaction being as high as 0.1 to 0.3%. These conclusions are validated by application to case histories corresponding to Mw ≈ 7, mostly in the San Francisco Bay Area of California during the 1989 Loma Prieta earthquake.

Keywords: permeability, lateral spreading, liquefaction, centrifuge modeling, shear wave velocity charts

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Authors: Neeraj Kumar, J. P. Narayan

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The effects of multiple Structure-Soil-Structure Interactions (SSSI) on the seismic wave-field is generally disregarded by earthquake engineers, particularly the surface waves which cause more damage to buildings. Closely built high rise buildings exchange substantial seismic energy with each other and act as a full-coupled dynamic system. In this paper, SSI effects on the building responses and the free field motion due to a small city consisting 25- homogenous buildings blocks of 10-storey are quantified. The rocking and translational behavior of building under Rayleigh wave loading is studied for different dimensions of the building. The obtained dynamic parameters of buildings revealed a reduction in building roof drift with an increase in number of buildings ahead of the considered building. The strain developed by vertical component of Rayleigh may cause tension in structural components of building. A matching of fundamental frequency of building for the horizontal component of Rayleigh wave with that for vertically incident SV-wave is obtained. Further, the fundamental frequency of building for the vertical vibration is approximately twice to that for horizontal vibration. The city insulation has caused a reduction of amplitude of Rayleigh wave up to 19.3% and 21.6% in the horizontal and vertical components, respectively just outside the city. Further, the insulating effect of city was very large at fundamental frequency of buildings for both the horizontal and vertical components. Therefore, it is recommended to consider the insulating effects of city falling in the path of Rayleigh wave propagation in seismic hazard assessment for an area.

Keywords: structure-soil-structure interactions, Rayleigh wave propagation, finite difference simulation, dynamic response of buildings

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Authors: Gregory E. Ofili

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Introduction and Objective: Climate change and a global economy mean farmers must adapt and gain access to affordable and reliable automation technologies. Key barriers include a lack of transportation, electricity, and internet service, coupled with costly enabling technologies and limited local subject matter expertise. Methodology/Approach: Resourcefulness is essential to mechanization on a farm. This runs contrary to the tech industry practice of planned obsolescence and disposal. One solution is plug-and-play hardware that allows farmer to assemble, repair, program, and service their own fleet of industrial machines. To that end, we developed a method of manufacturing low-cost utility robots, transport vehicles, and solar/wind energy harvesting systems, all running on an open-source Robot Operating System (ROS). We demonstrate this technology by fabricating a utility robot and an all-terrain (4X4) utility vehicle. Constructed of aluminum trusses and weighing just 40 pounds, yet capable of transporting 200 pounds of cargo, on sale for less than $2,000. Conclusions & Policy Implications: Electricity, internet, and automation are essential for productivity and competitiveness. With planned obsolescence, the priorities of technology suppliers are not aligned with the farmer’s realities. This patent-pending method of manufacturing low-cost industrial robots and electric vehicles has met its objective. To create low-cost machines, the farmer can assemble, program, and repair with basic hand tools.

Keywords: automation, robotics, utility robot, small-hold farm, robot operating system

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Authors: F. Deng, R. Sanchez, A. Beltran, S. Maestre

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The high nutritional value associated with seafood is related to the presence of essential trace elements. Moreover, seafood is considered an important source of energy, proteins, and long-chain polyunsaturated fatty acids. Generally, seafood is consumed cooked. Consequently, the nutritional value could be degraded. Seafood, such as fish, shellfish, and seaweed, could be considered as one of the main iodine sources. The deficient or excessive consumption of iodine could cause dysfunction and pathologies related to the thyroid gland. The main objective of this work is to evaluated iodine stability in hake (Merluccius) undergone different culinary techniques. The culinary process considered were: boiling, steaming, microwave cooking, baking, cooking en papillote (twisted cover with the shape of a sweet wrapper) and coating with a batter of flour and deep-frying. The determination of iodine was carried by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Regarding sample handling strategies, liquid-liquid extraction has demonstrated to be a powerful pre-concentration and clean-up approach for trace metal analysis by ICP techniques. Extraction with tetramethylammonium hydroxide (TMAH reagent) was used as a sample preparation method in this work. Based on the results, it can be concluded that the stability of iodine was degraded with the cooking processes. The major degradation was observed for the boiling and microwave cooking processes. The content of iodine in hake decreased up to 60% and 52%, respectively. However, if the boiling cooking liquid is preserved, this loss that has been generated during cooking is reduced. Only when the fish was cooked by following the cooking en papillote process the iodine content was preserved.

Keywords: cooking process, ICP-MS, iodine, hake

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Authors: Ágota Ábrahám, Md Nurul Islam, Karimane Zeghbib, Gábor Kemenesi, Sazeda Akter

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Collecting palm sap as a food source is an everyday practice in some parts of the world. However, the consumption of palm juice has been associated with regular infections and epidemics in parts of Bangladesh. This is attributed to fruit-eating bats and other vertebrates or invertebrates native to the area, contaminating the food with their body secretions during the collection process. The frequent intake of palm juice, whether as a processed food product or in its unprocessed form, is a common phenomenon in large areas. The range of pathogens suitable for human infection resulting from this practice is not yet fully understood. Additionally, the high sugar content of the liquid makes it an ideal culture medium for certain bacteria, which can easily propagate and potentially harm consumers. Rapid diagnostics, especially in remote locations, could mitigate health risks associated with palm juice consumption. The primary objective of this research is the rapid genomic detection and risk assessment of bacteria that may cause infections in humans through the consumption of palm juice. Utilizing state-of-the-art third-generation Nanopore metagenomic sequencing technology based on 16S rRNA, and identified bacteria primarily involved in fermenting processes. The swift metagenomic analysis, coupled with the widespread availability and portability of Nanopore products (including real-time analysis options), proves advantageous for detecting harmful pathogens in food sources without relying on extensive industry resources and testing.

Keywords: raw date palm sap, NGS, metabarcoding, food safety

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Authors: Ovanes Chakoyan

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MOH (mineral oil hydrocarbons), which consist of mineral oil saturated hydrocarbons(MOSH) and mineral oil aromatic hydrocarbons(MOAH), are present in various products such as vegetable oils, animal feed, foods, and infant formula. Contamination of foods with mineral oil hydrocarbons, particularly mineral oil aromatic hydrocarbons(MOAH), exhibiting carcinogenic, mutagenic, and hormone-disruptive effects. Identifying toxic substances among the many thousands comprising mineral oils in food samples is a difficult analytical challenge. A method based on an offline-solid phase extraction approach coupled with gas chromatography-triple quadrupole(GC-MS/MS) was developed for the determination of MOSH/MOAH in various products such as vegetable oils, animal feed, foods, and infant formula. A glass solid phase extraction cartridge loaded with 7 g of activated silica gel impregnated with 10 % silver nitrate for removal of olefins and lipids. The MOSH/MOAH fractions were eluated with hexane and hexane: dichloromethane : toluene, respectively. Each eluate was concentrated to 50 µl in toluene and injected on splitless mode into GC-MS/MS. Accuracy of the method was estimated as measurement of recovery of spiked oil samples at 2.0, 15.0, and 30.0 mg kg -1, and recoveries varied from 85 to 105 %. The method was applied to the different types of samples (sunflower meal, chocolate ships, santa milk chocolate, biscuits, infant milk, cornflakes, refined sunflower oil, crude sunflower oil), detecting MOSH up to 56 mg/kg and MOAH up to 5 mg/kg. The limit of quantification(LOQ) of the proposed method was estimated at 0.5 mg/kg and 0.3 mg/kg for MOSH and MOAH, respectively.

Keywords: MOSH, MOAH, GC-MS/MS, foods, solid phase extraction

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Authors: Mouhamadou Diop, Mohamed I. Hassan

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Molten metallic flow in metallurgical plant is highly turbulent and presents a complex coupling with heat transfer, phase transfer, chemical reaction, momentum transport, etc. Molten silicon flow has significant effect in directional solidification of multicrystalline silicon by affecting the temperature field and the emerging crystallization interface as well as the transport of species and impurities during casting process. Owing to the complexity and limits of reliable measuring techniques, computational models of fluid flow are useful tools to study and quantify these problems. The overall objective of this study is to investigate the potential of a traveling magnetic field for an efficient operating control of the molten metal flow. A multidimensional numerical model will be developed for the calculations of Lorentz force, molten metal flow, and the related phenomenon. The numerical model is implemented in a laboratory-scale silicon crystallization furnace. This study presents the potential of traveling magnetic field approach for an efficient operating control of the molten flow. A numerical model will be used to study the effects of magnetic force applied on the molten flow, and their interdependencies. In this paper, coupled and decoupled, steady and unsteady models of molten flow and crystallization interface will be compared. This study will allow us to retrieve the optimal traveling magnetic field parameter range for crystallization furnaces and the optimal numerical simulations strategy for industrial application.

Keywords: multidimensional, numerical simulation, solidification, multicrystalline, traveling magnetic field

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Authors: Vijaya K. Srivastava, Davide Spinello

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This paper presents performance of two robust gradient-based heuristic optimization procedures based on 3ⁿ enumeration and tunneling approach to seek global optimum of constrained integer problems. Both these procedures consist of two distinct phases for locating the global optimum of integer problems with a linear or non-linear objective function subject to linear or non-linear constraints. In both procedures, in the first phase, a local minimum of the function is found using the gradient approach coupled with hemstitching moves when a constraint is violated in order to return the search to the feasible region. In the second phase, in one optimization procedure, the second sub-procedure examines 3ⁿ integer combinations on the boundary and within hypercube volume encompassing the result neighboring the result from the first phase and in the second optimization procedure a tunneling function is constructed at the local minimum of the first phase so as to find another point on the other side of the barrier where the function value is approximately the same. In the next cycle, the search for the global optimum commences in both optimization procedures again using this new-found point as the starting vector. The search continues and repeated for various step sizes along the function gradient as well as that along the vector normal to the violated constraints until no improvement in optimum value is found. The results from both these proposed optimization methods are presented and compared with one provided by popular MS Excel solver that is provided within MS Office suite and other published results.

Keywords: constrained integer problems, enumerative search algorithm, Heuristic algorithm, Tunneling algorithm

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Authors: Velázquez Alejandro, Pradhan Sujan, Yoon Rokhyun, Sanada Yasushi

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The utilization of new materials as an alternative solution to decrease the environmental impact of the construction industry has been gaining more relevance in the architectural design and construction industry. One such material is cross-laminated timber (CLT), an engineered timber solution that excels for its faster construction times, workability, lightweight, and capacity for carbon storage. This material is usually used alone for the entire structure or combined with steel frames, but a hybrid with reinforced concrete (RC) is rarer. Since RC is one of the most used materials worldwide, a hybrid with CLT would allow further utilization of the latter, and in the process, it would help reduce the environmental impact of RC construction to achieve a sustainable society, but first, the structural performance of such hybrids must be understood. This paper focuses on proposing a model to predict the seismic performance of RC frames with CLT panels as infills. A series of static horizontal cyclic loading experiments were conducted on two 40% scale specimens of reinforced concrete frames with and without CLT panels at Osaka University, Japan. An analytical model was created to simulate the seismic performance of the RC frame with CLT infill based on the experimental results. The proposed model was verified by comparing the experimental and analytical results, showing that the load-deformation relationship and the failure mechanism agreed well with limited error. Hence, the proposed analytical model can be implemented for the seismic performance evaluation of the RC frames with CLT infill.

Keywords: analytical model, multi spring, performance evaluation, reinforced concrete, rocking mechanism, wooden wall

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Authors: Tsige Reda

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Essential oil of Thymus vulgaris was extracted by means of hydro-distillation. This study was done to investigate the chemical composition, antibacterial and antioxidant activities. The chemical composition of the essential oils was determined using gas chromatography coupled to mass spectroscopy (GC-MS). Using disc diffusion assay the antibacterial activity was assessed on one Gram-positive bacteria and one Gram-negative bacteria. The percentage oil yield of the essential oil was found to be 0.97 ± 0.08% (w/w) with yellow color. The physicochemical constants of the oil were also noted. The phytochemical screening of the plant extract revealed the presence of tannins, saponins, phenol, flavonoids, terpenoids, steroids and alkaloids. A total of 18 chemical constituents were identified by Gas Chromatography-Mass Spectroscopy analysis representing 100% of the total essential oil of Thymus vulgaris, with thymol (31.977%), o-cymene (29.992%), and carvacrol (14.541%). Previous studies have revealed that the thymol, o-cymen and carvacrol components of Thymus vulgaris are responsible for their biological activities. Thymus vulgaris have been used traditionally to treat a wide variety of infections. Based on the extensive use and lack of scientific evidence, a study was embarked upon to determine its bioactivity. The essential oil of Thymus vulgaris leaves exhibited higher activity towards the Gram-positive bacteria (Staphylococcus aurous) than the Gram-negative bacteria (Escherichia coli) and also has good antioxidant activity, and can be used medicinal and therapeutic applications. This activity may be due to the high amount of thymol, o-cymen and carvacrol.

Keywords: hydro-distillation, Thymus vulgaris, essential oil composition, phytochemical screening, physicochemical constants, antioxidant activity, antibacterial activity

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Authors: M. B. Peter

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The Sacrament of Penance and Reconciliation has long been upheld, by the Catholic Church, as one of the Sacraments of healing, mainly due to the sense of peace, tranquility and psychological quiescence it accords the penitent upon receiving Sacramental absolution of sin through the action of the priest. This paper explores the Sacramental character of this practice and the psychological benefits of the celebration of the Sacrament. This is achieved in two parts: firstly, by the intellectual engagement of Sacred Scripture and the consolidated Sacred Tradition that the Catholic magisterium protects and, secondly, via a broad survey of the works of Carl Gustav Jung and Orval Hobart Mowrer regarding confession and forgiveness. The former will serve to demonstrate the Catholic belief of the divine institution of the Sacrament whilst the latter will demonstrate how this belief, coupled with the existing benefit of confessing guilt, collectively bolsters the Sacrament’s overall psychological efficacy. Fundamentally, the analysis of Jung and Mowrer’s works demonstrate that man, as a naturally religious being, has an inherent need for the confession of his wrong that he might be alleviated of psychological guilt in obtaining forgiveness of a (divinely ordained) minister who is sanctioned to absolve, i.e. the priest. The paper also presents the curative effect of the celebration of this Sacrament, illustrating how, without the act of confession, man remains in moral isolation from God and man; and, that with it, man is relieved of the mysterious feeling of guilt which lies at the root of his disquiet of mind and disturbance of will. Thus, the paper penultimately establishes how the Sacrament of Reconciliation is positioned in that place where psychology and theology meet: man’s sense of guilt. It is Jung’s views on confession and forgiveness that ultimately bridge the chasm between psychology and Christianity.

Keywords: Catholic, confession, Jung, Mowrer, penance, psychology, Sacrament of Reconciliation

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Authors: Aleksandr Medvedev, Zakhar Slukovsii

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Waterbodies, which are located either within urban areas or nearby towns, permanently undergo anthropogenic load. The extent of the load can be determined via investigations of chemical composition of both water and sediments. Lakes, as a rule, are considered as a landscape depressions, hence they are capable of natural material accumulating, which has been delivered from the catchment area through rivers as well as temporary flows. As a result, lacustrine sediments (especially closed-basin lakes sediments) are considered as perfect archives, which are served for reconstructing past sedimentation process, assessment of the modern contamination level, and prognostication of possible ways of changing in the future. The purposes of the survey are to define a heavy metals content in lake sediments cores, which were retrieved from four urban lakes located in the southern part of Karelia Republic, and to ascertain the main sources of heavy metals input to these waterbodies. It is really crucial to be aware of heavy metals content in environment, because chemical composition of a landscape may have a significant effect on living organisms and people’s health. Sediment columns were sampled in a field with 2-cm intervals by a gravitational corer called «Limnos». The sediment samples were analyzed by inductively coupled plasma spectrometry (ICP MS) for 8 chemical elements (Pb, Cd, Zn, Cr, Ni, Cu, Mn, V). The highest concentrations of trace elements were established in the upper and middle layers of the cores. It has also been ascertained that the extent of contamination mostly depends on a remoteness of a lake from various pollution sources and features of the sources.

Keywords: bottom sediments, environmental pollution, heavy metals, lakes

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Authors: Alexander N. Pisarchik, Parth Chholak

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Intrinsic brain noise was estimated via magneto-encephalograms (MEG) recorded during perception of flickering visual stimuli with frequencies of 6.67 and 8.57 Hz. First, we measured the mean phase difference between the flicker signal and steady-state event-related field (SSERF) in the occipital area where the brain response at the flicker frequencies and their harmonics appeared in the power spectrum. Then, we calculated the probability distribution of the phase fluctuations in the regions of frequency locking and computed its kurtosis. Since kurtosis is a measure of the distribution’s sharpness, we suppose that inverse kurtosis is related to intrinsic brain noise. In our experiments, the kurtosis value varied among subjects from K = 3 to K = 5 for 6.67 Hz and from 2.6 to 4 for 8.57 Hz. The majority of subjects demonstrated leptokurtic kurtosis (K < 3), i.e., the distribution tails approached zero more slowly than Gaussian. In addition, we found a strong correlation between kurtosis and brain complexity measured as the correlation dimension, so that the MEGs of subjects with higher kurtosis exhibited lower complexity. The obtained results are discussed in the framework of nonlinear dynamics and complex network theories. Specifically, in a network of coupled oscillators, phase synchronization is mainly determined by two antagonistic factors, noise, and the coupling strength. While noise worsens phase synchronization, the coupling improves it. If we assume that each neuron and each synapse contribute to brain noise, the larger neuronal network should have stronger noise, and therefore phase synchronization should be worse, that results in smaller kurtosis. The described method for brain noise estimation can be useful for diagnostics of some brain pathologies associated with abnormal brain noise.

Keywords: brain, flickering, magnetoencephalography, MEG, visual perception, perception time

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Authors: Saurav S. Rath, Birendra K. David

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Generic pharmaceutical industry has to operate in strict timelines of product development and scale-up from lab to plant. Hence, detailed product & process understanding and implementation of appropriate mechanistic modelling and Quality-by-design (QbD) approaches are imperative in the product life cycle. This work provides example cases of such efforts in topical dosage products. Topical products are typically in the form of emulsions, gels, thick suspensions or even simple solutions. The efficacy of such products is determined by characteristics like rheology and morphology. Defining, and scaling up the right manufacturing process with a given set of ingredients, to achieve the right product characteristics presents as a challenge to the process engineer. For example, the non-Newtonian rheology varies not only with CPPs and CMAs but also is an implicit function of globule size (CQA). Hence, this calls for various mechanistic models, to help predict the product behaviour. This paper focusses on such models obtained from computational fluid dynamics (CFD) coupled with population balance modelling (PBM) and constitutive models (like shear, energy density). In a special case of the use of high shear homogenisers (HSHs) for the manufacture of thick emulsions/gels, this work presents some findings on (i) scale-up algorithm for HSH using shear strain, a novel scale-up parameter for estimating mixing parameters, (ii) non-linear relationship between viscosity and shear imparted into the system, (iii) effect of hold time on rheology of product. Specific examples of how this approach enabled scale-up across 1L, 10L, 200L, 500L and 1000L scales will be discussed.

Keywords: computational fluid dynamics, morphology, quality-by-design, rheology

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Authors: Mohamed Gouda

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Antibacterial wound dressings based on cellulose nanofibers containing different metal nanoparticles (CMC-MNPs) were synthesized using an electrospinning technique. First, the composite of carboxymethyl cellulose containing different metal nanoparticles (CMC/MNPs), such as copper nanoparticles (CuNPs), iron nanoparticles (FeNPs), zinc nanoparticles (ZnNPs), cadmium nanoparticles (CdNPs) and cobalt nanoparticles (CoNPs) were synthesized, and finally, these composites were transferred to the electrospinning process. Synthesized CMC-MNPs were characterized using scanning electron microscopy (SEM) coupled with high-energy dispersive X-ray (EDX) and UV-visible spectroscopy used to confirm nanoparticle formation. The SEM images clearly showed regular flat shapes with semi-porous surfaces. All MNPs were well distributed inside the backbone of the cellulose without aggregation. The average particle diameters were 29-39 nm for ZnNPs, 29-33 nm for CdNPs, 25-33 nm for CoNPs, 23-27 nm for CuNPs and 22-26 nm for FeNPs. Surface morphology, water uptake and release of MNPs from the nanofibers in water and antimicrobial efficacy were studied. SEM images revealed that electrospun CMC-MNPs nanofibers are smooth and uniformly distributed without bead formation with average fiber diameters in the range of 300 to 450 nm. Fiber diameters were not affected by the presence of MNPs. TEM images showed that MNPs are present in/on the electrospun CMC-MNPs nanofibers. The diameter of the electrospun nanofibers containing MNPs was in the range of 300–450 nm. The MNPs were observed to be spherical in shape. The CMC-MNPs nanofibers showed good hydrophilic properties and had excellent antibacterial activity against the Gram-negative bacteria Escherichia coli and the Gram-positive bacteria Staphylococcus aureus.

Keywords: electrospinning technique, metal nanoparticles, cellulosic nanofibers, wound dressing

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Authors: Levent Dumenci, Laura A. Siminoff

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Health literacy has been shown to predict a variety of health outcomes. Reliable identification of persons with limited cancer health literacy (LCHL) has been proved questionable with existing instruments using an arbitrary cut point along a continuum. The CHLT-6, however, uses a latent mixture modeling approach to identify persons with LCHL. The purpose of this study was to estimate two-week and six-month stability of identifying persons with LCHL using the CHLT-6 with a discrete latent variable approach as the underlying measurement structure. Using a test-retest design, the CHLT-6 was administered to cancer patients with two-week (N=98) and six-month (N=51) intervals. The two-week and six-month latent test-retest agreements were 89% and 88%, respectively. The chance-corrected latent agreements estimated from Dumenci’s latent kappa were 0.62 (95% CI: 0.41 – 0.82) and .47 (95% CI: 0.14 – 0.80) for the two-week and six-month intervals, respectively. High levels of latent test-retest agreement between limited and adequate categories of cancer health literacy construct, coupled with moderate to good levels of change-corrected latent agreements indicated that the CHLT-6 classification of limited versus adequate cancer health literacy is relatively stable over time. In conclusion, the measurement structure underlying the instrument allows for estimating classification errors circumventing limitations due to arbitrary approaches adopted by all other instruments. The CHLT-6 can be used to identify persons with LCHL in oncology clinics and intervention studies to accurately estimate treatment effectiveness.

Keywords: limited cancer health literacy, the CHLT-6, discrete latent variable modeling, latent agreement

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Authors: Erwan Negre, Ewan J. O'Connor, Juha Toivonen

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The need for CO2 monitoring technologies grows simultaneously with the worldwide concerns regarding environmental challenges. To that purpose, we developed a compact coherent all-fiber ranged-resolved Differential Absorption Lidar (RR-DIAL). It has been designed along a tunable 2x1fiber optic switch set to a frequency of 1 Hz between two Distributed FeedBack (DFB) lasers emitting in the continuous-wave mode at 1571.41 nm (absorption line of CO2) and 1571.25 nm (CO2 absorption-free line), with linewidth and tuning range of respectively 1 MHz and 3 nm over operating wavelength. A three stages amplification through Erbium and Erbium-Ytterbium doped fibers coupled to a Radio Frequency (RF) driven Acousto-Optic Modulator (AOM) generates 100 ns pulses at a repetition rate from 10 to 30 kHz with a peak power up to 2.5 kW and a spatial resolution of 15 m, allowing fast and highly resolved CO2 profiles. The same afocal collection system is used for the output of the laser source and the backscattered light which is then directed to a circulator before being mixed with the local oscillator for heterodyne detection. Packaged in an easily transportable box which also includes a server and a Field Programmable Gate Array (FPGA) card for on-line data processing and storing, our setup allows an effective and quick deployment for versatile in-situ analysis, whether it be vertical atmospheric monitoring, large field mapping or sequestration site continuous oversight. Setup operation and results from initial field measurements will be discussed.

Keywords: CO2 profiles, coherent DIAL, in-situ atmospheric sensing, near infrared fiber source

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Authors: Larry E. Udu, Joseph N. Edeh

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Unarguably, the land is an indispensable factor of production and has been instrumental to numerous conflicts between crop farmers and herders in Nigeria. The conflicts pose a grave challenge to life and property, food security and ultimately to sustainable socio-economic development of the nation. The paper examines the causes of the Fulani herders/farmers conflicts, particularly in the Middle Belt; numerity of occurrences and extent of damage and their socio-economic implications. Content Analytical Approach was adopted as methodology wherein data was extensively drawn from the secondary source. Findings reveal that major causes of the conflict are attributable to violation of tradition and laws, trespass and cultural factors. Consequently, the numerity of attacks and level of fatality coupled with displacement of farmers, destruction of private and public facilities impacted negatively on farmers output with their attendant socio-economic implications on sustainable livelihood of the people and the nation at large. For instance, Mercy Corps (a Global Humanitarian Organization) in its research, 2013-2016 asserts that a loss of $14billion within 3 years was incurred and if the conflict were resolved, the average affected household could see increase income by at least 64 percent and potentially 210 percent or higher and that states affected by the conflicts lost an average of 47 percent taxes/IGR. The paper therefore recommends strict adherence to grazing laws; platform for dialogue bothering on compromises where necessary and encouragement of cattle farmers to build ranches for their cattle according to international standards.

Keywords: conflict, farmers, herders, Nigeria, socio-economic implications

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Authors: A. Fernandez Zuvich, I. Gana Watkins, H. Zolotucho, H. Troiani, A. Caneiro, M. Prado, A. L. Soldati

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The study of actinide nanoparticles (NPs) has attracted the attention of the scientific community not only because the lack of information about their ecotoxicological effects but also because the use of NPs could open a new way in the production of nuclear energy. Indeed, it was recently demonstrated that UO2 NPs sintered pellets exhibit closed porosity with improved fission gas retention and radiation-tolerance , ameliorated mechanical properties, and less detriment of the thermal conductivity upon use, making them an interesting option for new nuclear fuels. In this work, we used a combination of diffraction and microscopy tools to characterize the morphology, the crystalline structure and the composition of UO2 nanoparticles doped with 10%wt Gd2O3. The particles were synthesized by a modified sol-gel method at low temperatures. X-ray Diffraction (XRD) studies determined the presence of a unique phase with the cubic structure and Fm3m spatial group, supporting that Gd atoms substitute U atoms in the fluorite structure of UO2. In addition, Field Emission Gun Scanning (FEG-SEM) and Transmission (FEG-TEM) Electron Microscopy images revealed the presence of micrometric agglomerates of nanoparticles, with rounded morphology and an average crystallite size < 50 nm. Energy Dispersive Spectroscopy (EDS) coupled to TEM determined the presence of Gd in all the analyzed crystallites. Besides, FEG-SEM-EDS showed a homogeneous concentration distribution at the micrometer scale indicating that the small size of the crystallites compensates the variation in composition by averaging a large number of crystallites. These techniques, as combined tools resulted thus essential to find out details of morphology and composition distribution at the sub-micrometer scale, and set a standard for developing and analyzing nanoparticulated nuclear fuels.

Keywords: actinide nanoparticles, burnable poison, nuclear fuel, sol-gel

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Authors: Li Maksym, Prabhakar M. N., Jung-Il Song

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In this study, a flame retardant and hydrophobic cotton textile were prepared by utilizing a renewable halogen-free bio-based solution based on chitosan, urea, and phytic acid, named bio-flame retardant liquid (BFL), through facile dip-coating technology. Deposition of BFL on the surface of the cotton was confirmed by Fourier-transform infrared spectroscopy and scanning electron microscope coupled with energy-dispersive X-ray spectrometer. Thermal and flame retardant properties of the cottons were studied with thermogravimetric analysis, differential scanning calorimetry, vertical flame test, cone calorimeter test. Only with 8.8% of dry weight gain treaded cotton showed self-extinguish properties during fire test. Cone calorimeter test revealed a reduction of peak heat release rate from 203.2 to 21 kW/m2 and total heat release from 20.1 to 2.8 MJ/m2. Incidentally, BFL remarkably improved the thermal stability of flame retardant cotton from expressed in an enhanced amount of char at 700 °C (6.7 vs. 33.5%). BFL initiates the formation of phosphorous and silica contain char layer whichrestrains the propagation of heat and oxygen to unburned materialstrengthen by the liberation of non-combustible gases, which reduce the concentration of flammable volatiles and oxygen hence reducing the flammability of cotton. In addition, hydrophobicity and specific ignition test for upholstery application were performed. In conjunction, the proposed flame retardant cotton is potentially translatable to be utilized as upholstery materials in public transport.

Keywords: cotton farbic, flame retardancy, surface coating, intumescent mechanism

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Authors: Giorgio Visentin, Alexei A. Buchachenko

Abstract:

Recent proposals to use Yb dimer as an optical clock and as a sensor for non-Newtonian gravity imply the knowledge of its interaction potential. Here, the ground-state Born-Oppenheimer Yb₂ potential energy curve is represented by a semi-analytical function, consisting of short- and long-range contributions. For the former, the systematic ab initio all-electron exact 2-component scalar-relativistic CCSD(T) calculations are carried out. Special care is taken to saturate diffuse basis set component with the atom- and bond-centered primitives and reach the complete basis set limit through n = D, T, Q sequence of the correlation-consistent polarized n-zeta basis sets. Similar approaches are used to the long-range dipole and quadrupole dispersion terms by implementing the CCSD(3) polarization propagator method for dynamic polarizabilities. Dispersion coefficients are then computed through Casimir-Polder integration. The semiclassical constraint on the number of the bound vibrational levels known for the ¹⁷⁴Yb isotope is used to scale the potential function. The scaling, based on the most accurate ab initio results, bounds the interaction energy of two Yb atoms within the narrow 734 ± 4 cm⁻¹ range, in reasonable agreement with the previous ab initio-based estimations. The resulting potentials can be used as the reference for more sophisticated models that go beyond the Born-Oppenheimer approximation and provide the means of their uncertainty estimations. The work is supported by Russian Science Foundation grant # 17-13-01466.

Keywords: ab initio coupled cluster methods, interaction potential, semi-analytical function, ytterbium dimer

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Authors: Salama A. Ouf, Amera A. El-Adly, Abdelaleam H. Mohamed

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Dermatophytosis is the infection of keratinized tissues such as hair, nail and the stratum corneum of the skin by dermatophytic fungi. Infection is generally cutaneous and restricted to the non-living cornified layers because of the inability of the fungi to penetrate the deeper tissues or organs of immunocompetent hosts. In Saudi Arabia, Onychomycosis is the most frequent infection (40.3%), followed by tinea capitis (21.9%), tinea pedis (16%), tinea cruris (15.1%), and tinea corporis (6.7%). Several azole compounds have been tried to control dermatophytic infection, however, the azole-containing medicines may interfere with the activity of hepatic microsomal enzymes, sex and thyroid hormones, and testosterone biosynthesis. In this research, antibody-conjugated nanoparticles stimulated by cold plasma and laser were evaluated in vitro against some dermatophytes isolated from the common types of tinea. Different types of nanomaterials were tested but silver nanoparticles (AgNPs) were proved to be most effective against the dermatophytes under test. The use of cold plasma coupled with antibody-conjugated nano-particles has severe impact on dermatophytes where the inhibition of growth, spore germination keratinase activity was more than 88% in the case of Trichophyton rubrum, T. violaceum, Microsprum canis and M. gypseum. Complete inhibition of growth for all dermatophytes was brought about by the interaction of conjugated nanoparticles, with cold plasma and laser treatment. The in vivo test with inoculated guinea pigs achieved promising results where the recovery from the infection reached 95% in the case of M. canis –inoculated pigs treated with AgNPs pretreated with cold plasma and laser.

Keywords: cold plasma, dermatophytes, laser, silver nanoparticles

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Authors: Guo-Hui Lu, Jing-Yi Cai, Ke-Yan Tan, Xiao-Cai Yin, Yu Zheng, Peng-Wei Shao, Yong-Liang Yang

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Soil erosion around abandoned mines is one of the important geological agents for pollutant diffuses to the lower reaches of the local river basin system. River loading of pollutants is an important parameter for remediation of abandoned mines. In order to obtain information on pollutant transport and diffusion downstream in mining area, the small tributary system of the Xiaxi River in Wanshan District of Guizhou Province was selected as the research area. Sediment and suspended matter samples were collected and determined for Pb, As, Hg, Zn, Co, Cd, Cu, Ni, Cr, and Mn by inductively coupled plasma mass spectrometry (ICP-MS) and atomic fluorescence spectrometry (AFS) with the pretreatment of wet digestion. Discussions are made for pollution status and spatial distribution characteristics. The total Hg content in the sediments ranged from 0.45 to 16.0 g/g (dry weight) with an average of 5.79 g/g, which was ten times higher than the limit of Class II soil for mercury by the National Soil Environmental Quality Standard. The maximum occurred at the intersection of the Jin River and the Xiaxi River. The potential ecological hazard index (RI) was used to evaluate the ecological risk of heavy metals in the sediments. The average RI value for the whole study area suggests the high potential ecological risk level. High Cd potential ecological risk was found at individual sites.

Keywords: heavy metal, risk assessment, sediment, suspended matter, Wanshan mercury mine, small tributary system

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Authors: A. Jourani, C. Trevisiol, S. Bouvier

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The aim of this work is to study the coupled effect of microstructure and surface roughness on friction coefficient, wear resistance and wear mechanisms. Friction tests on 35NCD16 steel are performed under different normal loads (50-110 N) on a pin-on-plane configuration at cyclic sliding with abrasive silicon carbide grains ranging from 35 µm to 200 µm. To vary hardness and microstructure, the specimens are subjected to water quenching and tempering at various temperatures from 200°C to 600°C. The evolution of microstructures and wear mechanisms of worn surfaces are analyzed using scanning electron microscopy (SEM). For a given microstructure and hardness, the friction coefficient decreases with increasing of normal load and decreasing of the abrasive particle size. The wear rate increase with increasing of normal load and abrasive particle size. The results also reveal that there is a critical hardness Hcᵣᵢₜᵢcₐₗ around 430 Hv which maximizes the friction coefficient and wear rate. This corresponds to a microstructure transition from martensite laths to carbides and equiaxed grains, for a tempering around 400°C. Above Hcᵣᵢₜᵢcₐₗ the friction coefficient and the amount of material loss decrease with an increase of hardness and martensite volume fraction. This study also shows that the debris size and the space between the abrasive particles decrease with a reduction in the particle size. The coarsest abrasive grains lost their cutting edges, accompanied by particle damage and empty space due to the particle detachment from the resin matrix. The compact packing nature of finer abrasive papers implicates lower particle detachment and facilitates the clogging and the transition from abrasive to adhesive wear.

Keywords: martensite, microstructure, friction, wear, surface roughness

Procedia PDF Downloads 158

Authors: Bhogendra Mishra, Andy Nelson, Mirco Boschetti, Lorenzo Busetto, Alice Laborte

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Rice is grown on over 100 million hectares in almost every country of Asia. It is the most important staple crop for food security and has high economic and cultural importance in Asian societies. The combination of genetic diversity and management options, coupled with the large geographic extent means that there is a large variation in seasonality (when it is grown) and cropping intensity (how often it is grown per year on the same plot of land), even over relatively small distances. Seasonality and intensity can and do change over time depending on climatic, environmental and economic factors. Detecting where and when these changes happen can provide information to better understand trends in regional and even global rice production. Remote sensing offers a unique opportunity to estimate these trends. We apply the recently published PhenoRice algorithm to 14 years of moderate resolution remote sensing (MODIS) data (utilizing 250m resolution 16 day composites from Terra and Aqua) to estimate seasonality and cropping intensity per year and changes over time. We compare the results to the surveyed data collected by International Rice Research Institute (IRRI). The study results in a unique and validated dataset on the extent and change of extent, the seasonality and change in seasonality and the cropping intensity and change in cropping intensity between 2003 and 2016 for the Philippines. Observed trends and their implications for food security and trade policies are also discussed.

Keywords: rice, cropping intensity, moderate resolution remote sensing (MODIS), phenology, seasonality

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Authors: Salma Baig, Bakrudeen Ali Ahmad, Ainnul Hamidah Syahadah Azizan, Hapipah Mohd Ali, Elham Rouhollahi, Mahmood Ameen Abdulla

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Free radical damage induced by reactive oxygen species (ROS) contributes to etiology of many chronic diseases, cancer being one of them. Recent studies have been successful in ROS targeted therapies via antioxidants using mouse models in cancer therapeutics. The present study was designed to scrutinize anticancer activity, antioxidant activity of 5 different extracts of Thymus serpyllum in MDA-MB-231, MCF-7, HepG2, HCT-116, PC3, and A549. Identification of the phytochemicals present in the most active extract of Thymus serpyllum was conducted using gas chromatography coupled with mass spectrophotometry and antioxidant activity was measured by using DPPH radical scavenging and FRAP assay. Anticancer impact of the extract in terms of IC50 was evaluated using MTT cell viability assay. Results revealed that the hexane extract showed the best anticancer activity in HepG2 (Liver Carcinoma Cell Line) with an IC50 value of 23 ± 0.14 µg/ml followed by 25 µg/ml in HCT-116 (Colon Cancer Cell Line), 30 µm/ml in MCF-7 (Breast Cancer Cell Line), 35 µg/ml in MDA-MB-231 (Breast Cancer Cell Line), 57 µg/ml in PC3 (Prostate Cancer Cell Line) and 60 µg/ml in A549 (Lung Carcinoma Cell Line). GC-MS profile of the hexane extract showed the presence of 31 compounds with carvacrol, thymol and thymoquione being the major compounds. Phenolics such as Vitamin E, terpinen-4-ol, borneol and phytol were also identified. Hence, here we present the first report on cytotoxicity of hexane extract of Thymus serpyllum extract in HepG2 cell line with a robust anticancer activity with an IC50 of 23 ± 0.14 µg/ml.

Keywords: Thymus serpyllum L., hexane extract, GC-MS profile, antioxidant activity, anticancer activity, HepG2 cell line

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Authors: Timothy L. Porter, T. Randy Dillingham

Abstract:

Vegetation growth and decomposition, along with soil microbial activity play a complex role in the production of greenhouse gases originating in forest soils. The absorption or emission (respiration) of these gases is a function of many factors relating to the soils themselves, the plants, and the environment in which the plants are growing. For this study, we have constructed a battery-powered, portable field mass spectrometer for use in analyzing gases in the soils surrounding trees, plants, and other areas. We have used the instrument to sample in real-time the greenhouse gases carbon dioxide and methane in soils where plant life may be contributing to the production of gases such as methane. Gases such as isoprene, which may help correlate gas respiration to microbial activity have also been measured. The instrument is composed of a quadrupole mass spectrometer with part per billion or better sensitivity, coupled to battery-powered turbo and diaphragm pumps. A unique ambient air pressure differentially pumped intake apparatus allows for the real-time sampling of gases in the soils from the surface to several inches below the surface. Results show that this instrument is capable of instant, part-per-billion sensitivity measurement of carbon dioxide and methane in the near surface region of various forest soils. We have measured differences in soil respiration resulting from forest thinning, forest burning, and forest logging as compared to pristine, untouched forests. Further studies will include measurements of greenhouse gas respiration as a function of temperature, microbial activity as measured by isoprene production, and forest restoration after fire.

Keywords: forest, soil, greenhouse, quadrupole

Procedia PDF Downloads 116