Search results for: simple chemical precipitation route

Authors: Tomasz Łęga, Marta Sosnowska, Mirosława Panasiuk, Lilit Hovhannisyan, Beata Gromadzka, Marcin Olszewski, Sabina Zoledowska, Dawid Nidzworski

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Toxic heavy metal ion contamination of industrial wastewater has recently become a significant environmental concern in many regions of the world. Although the majority of heavy metals are naturally occurring elements found on the earth's surface, anthropogenic activities such as mining and smelting, industrial production, and agricultural use of metals and metal-containing compounds are responsible for the majority of environmental contamination and human exposure. The permissible limits (ppm) for heavy metals in food, water and soil are frequently exceeded and considered hazardous to humans, other organisms, and the environment as a whole. Human exposure to highly nickel-polluted environments causes a variety of pathologic effects. In 2008, nickel received the shameful name of “Allergen of the Year” (GILLETTE 2008). According to the dermatologist, the frequency of nickel allergy is still growing, and it can’t be explained only by fashionable piercing and nickel devices used in medicine (like coronary stents and endoprostheses). Effective remediation methods for removing heavy metal ions from soil and water are becoming increasingly important. Among others, methods such as chemical precipitation, micro- and nanofiltration, membrane separation, conventional coagulation, electrodialysis, ion exchange, reverse and forward osmosis, photocatalysis and polymer or carbon nanocomposite absorbents have all been investigated so far. The importance of environmentally sustainable industrial production processes and the conservation of dwindling natural resources has highlighted the need for affordable, innovative biosorptive materials capable of recovering specific chemical elements from dilute aqueous solutions. The use of combinatorial phage display techniques for selecting and recognizing material-binding peptides with a selective affinity for any target, particularly inorganic materials, has gained considerable interest in the development of advanced bio- or nano-materials. However, due to the limitations of phage display libraries and the biopanning process, the accuracy of molecular recognition for inorganic materials remains a challenge. This study presents the isolation, identification and characterisation of metal binding phage clones that preferentially recover nickel.

Keywords: Heavy metal recovery, cleaning water, phage display, nickel

Procedia PDF Downloads 99

Authors: P. Karalis, E. Dotsika, A. Godelitsas, M. Tassi, D. Ignatiadou

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Glass artefacts originated from Northern Greece, dated between 1st and 6th AC, were analyzed for their oxygen isotopic and chemical compositions in order to identify their raw materials provenance. The chemical composition of these glasses is rather heterogeneous although they are all obtained with natron as flux, having both K₂O and MgO contents lower than 1.5 wt%. The majority of these samples have a homogeneous oxygen isotopic composition (𝛿18O= 16‰,), which is equal to or very close to the mean value of “Roman” glass (from about 15‰ to 16.0‰). The rest of the samples present heavily enriched 𝛿18O values that indicate that their raw materials differ from those normally used in Roman and Medieval glass production, and this matches with the possibility of the different origins of these materials. So, all these fragments are soda-lime-silica natron-glass produced from natron, possibly coming from more than one source.

Keywords: ancient glass, provenance of raw materials of ancient glass, roman glass, oxygen isotope analysis in glass

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Authors: Wei Ji

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This study was conducted in the Kansas City metropolitan area of the United States, which has experienced significant urban sprawling in recent decades. The remote sensing of land cover changes in this area spanned over four decades from 1972 through 2010. The project was implemented in two stages: the first stage focused on detection of long-term trends of urban land cover change, while the second one examined how to detect the coupled effects of human impact and climate change on urban landscapes. For the first-stage study, six Landsat images were used with a time interval of about five years for the period from 1972 through 2001. Four major land cover types, built-up land, forestland, non-forest vegetation land, and surface water, were mapped using supervised image classification techniques. The study found that over the three decades the built-up lands in the study area were more than doubled, which was mainly at the expense of non-forest vegetation lands. Surprisingly and interestingly, the area also saw a significant gain in surface water coverage. This observation raised questions: How have human activities and precipitation variation jointly impacted surface water cover during recent decades? How can we detect such coupled impacts through remote sensing analysis? These questions led to the second stage of the study, in which we designed and developed approaches to detecting fine-scale surface waters and analyzing coupled effects of human impact and precipitation variation on the waters. To effectively detect urban landscape changes that might be jointly shaped by precipitation variation, our study proposed “urban wetscapes” (loosely-defined urban wetlands) as a new indicator for remote sensing detection. The study examined whether urban wetscape dynamics was a sensitive indicator of the coupled effects of the two driving forces. To better detect this indicator, a rule-based classification algorithm was developed to identify fine-scale, hidden wetlands that could not be appropriately detected based on their spectral differentiability by a traditional image classification. Three SPOT images for years 1992, 2008, and 2010, respectively were classified with this technique to generate the four types of land cover as described above. The spatial analyses of remotely-sensed wetscape changes were implemented at the scales of metropolitan, watershed, and sub-watershed, as well as based on the size of surface water bodies in order to accurately reveal urban wetscape change trends in relation to the driving forces. The study identified that urban wetscape dynamics varied in trend and magnitude from the metropolitan, watersheds, to sub-watersheds in response to human impacts at different scales. The study also found that increased precipitation in the region in the past decades swelled larger wetlands in particular while generally smaller wetlands decreased mainly due to human development activities. These results confirm that wetscape dynamics can effectively reveal the coupled effects of human impact and climate change on urban landscapes. As such, remote sensing of this indicator provides new insights into the relationships between urban land cover changes and driving forces.

Keywords: urban land cover, human impact, climate change, rule-based classification, across-scale analysis

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Authors: Amer Dawoud, Jesy Motchaalangaram, Arati Biswakarma, Wujan Mio, Karl Wallace

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The development of an embedded miniaturized drone-based system for remote detection of Chemical Warfare Agents (CWA) is proposed. The paper focuses on the software/hardware system design of the electrochemical Cyclic Voltammetry (CV) and Differential Pulse Voltammetry (DPV) signal processing for future deployment on drones. The paper summarizes the progress made towards hardware and electrochemical signal processing for signature detection of CWA. Also, the miniature potentiostat signal is validated by comparing it with the high-end lab potentiostat signal.

Keywords: drone-based, remote detection chemical warfare agents, miniaturized, potentiostat

Procedia PDF Downloads 136

Authors: N. Y. H. Konagano

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Riverside population of Brazilian amazon suffers drinking water scarcity, seeking alternative water resources such as well and rivers, ordinary polluted. Although Amazon Region holds high annual river inflow and enough available of underground water, human activities have compromised the conservation of water resources. In addition, decentralized rural households make difficult to access of potable water. Main objective is to analyze quantitatively the potential of rainwater harvesting to human consumption at Marupaúba community, located in northeast of Amazon region, Brazil. Methods such as historical rainfall data series of municipality of Tomé-Açu at Pará state were obtained from Hydrological Information System of National Water Agency (ANA). Besides, Rippl method was used to calculate, mainly, volume of the reservoir based on difference of water demand and volume available through rainwater using as references two houses (CA I and CA II) as model of rainwater catchment and supply. Results presented that, from years 1984 to 2017, average annual precipitation was 2.607 mm, average maximum precipitation peak was 474 mm on March and average minimum peak on September was 44 mm. All months, of a year, surplus volume of water have presented in relation to demand, considering catchment area (CA) I = 134.4m² and demand volume =0.72 m³/month; and, CA II = 81.84 m² and demand volume = 0.48 m³/month. Based on results, it is concluded that it is feasible to use rainwater for the supply of the rural community Marupaúba, since the access of drinking water is a human right and the lack of this resource compromises health and daily life of human beings.

Keywords: Amazon Region, rainwater harvesting, rainwater resource, rural community

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Authors: Divya Pradip Roy, Md. Zahirul Alam Chowdhury

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Electromyography (EMG) sensors are generally used to record the electrical activity produced by skeletal muscles. The conventional EMG sensors available in the market are expensive. This research suggests a low cost EMG sensor design which can be built with simple devices within our reach. In this research, one instrumentation amplifier, two high pass filters, two low pass filters and an inverting amplifier is connected sequentially. The output from the circuit exhibits electrical potential generated by the muscle cells when they are neurologically activated. This electromyography signal is used to control prosthetic devices, identifying neuromuscular diseases and for various other purposes.

Keywords: EMG, high pass filter, instrumentation amplifier, inverting amplifier, low pass filter, neuromuscular

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Authors: Salah Menouar, Sara Hassoul

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The dynamic of time-dependent three coupled oscillators is studied through an approach based on decoupling of them using the unitary transformation method. From a first unitary transformation, the Hamiltonian of the complicated original system is transformed to an equal but a simple one associated with the three coupled oscillators of which masses are unity. Finally, we diagonalize the matrix representation of the transformed hamiltonian by using a unitary matrix. The diagonalized Hamiltonian is just the same as the Hamiltonian of three simple oscillators. Through these procedures, the coupled oscillatory subsystems are completely decoupled. From this uncouplement, we can develop complete dynamics of the whole system in an easy way by just examining each oscillator independently. Such a development of the mechanical theory can be done regardless of the complication of the parameters' variations.

Keywords: schrödinger equation, hamiltonian, time-dependent three coupled oscillators, unitary transformation

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Authors: Ajit Kumar Behera, Saranya P., Sudhir Kumar, Krishnakumar A

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The stable isotope (δ¹⁸ O and δ²H) composition of groundwater of the coastal areas of Periyar and Mahanadi basins falling along East and West coast of India during North-East (NE) monsoon season have been studied. The east and west coast regions are surrounded by the Bay of Bengal and the Arabian Sea respectively, which are considered to be the primary sources for precipitation over India. The major difference between the Bay of Bengal and the Arabian Sea is that a number of large rivers feed the Bay of Bengal, whereas the Arabian Sea is fed by very few small rivers, resulting in enriched stable isotopic composition of the Arabian Sea than the Bay of Bengal. Previous studies have reported depleted ratios of stable isotopes during Northeast monsoon along East and West coasts due to the influence of the Bay of Bengal moisture source. The isotopic composition of groundwater of the Mahanadi delta in the east coast region varies from -6.87 ‰ to -3.40 ‰ for δ¹⁸ O and -45.42 ‰ to -22.43‰ for δ²H. However, the groundwater of the Periyar basin in the west coast has enriched stable isotope value varying from -4.3‰ to -2.5 ‰ for δ¹⁸ O and for δ²H from -23.7 to -6.4 ‰ which is a characteristic of South-West monsoon season. This suggests the groundwater system of the Mahanadi delta and the Periyar basins are influenced by dissimilar moisture sources. The δ¹⁸ O and δ² H relationship (δ²H= 6.513 δ¹⁸ O - 1.39) and d-excess value (< 10) in the east coast region indicates the influence of NE monsoon implying the quick groundwater recharge after precipitation with significant amount of evaporation. In contrast, the δ¹⁸ O and δ²H regression line (δ²H= 8.408 δ¹⁸ O + 11.71) with high d-excess value (>10) in the west coast region implies delayed recharge due to SW monsoon. The observed isotopic enrichment in west coast suggests that NE winter monsoon rainfall does not replenish groundwater quick enough to produce isotopic depletion during the season.

Keywords: Arabian sea, bay of Bengal, groundwater, monsoon, stable isotope

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Authors: Lakshmi Sirisha Kotikalapudi

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Atenolol, the widely used antihypertensive drug is ionisable and degrades in the acidic environment of the GIT lessening the bioavailability. Transdermal route may be selected as an alternative to enhance the bioavailability. Half-life of the drug is 6-7 hours suggesting the requirement of prolonged release of the drug. The present work of transdermal niosomal gel aims to extend release of the drug and increase the bioavailability. Ethanol injection method was used for the preparation of niosomes using span-60 and cholesterol at different molar ratios following central composite design. The prepared niosomes were characterized for size, zeta-potential, entrapment efficiency, drug content and in-vitro drug release. Optimized formulation was selected by statistically analyzing the results obtained using the software Stat-Ease Design Expert. The optimized formulation also showed high drug retention inside the vesicles over a period of three months at a temperature of 4 °C indicating stability. Niosomes separated as a pellet were dried and incorporated into the hydrogel prepared using chitosan a natural polymer as a gelling agent. The effect of various chemical permeation enhancers was also studied over the gel formulations. The prepared formulations were characterized for viscosity, pH, drug release using Franz diffusion cells, and skin irritation test as well as in-vivo pharmacological activities. Atenolol niosomal gel preparations showed the prolonged release of the drug and pronounced antihypertensive activity indicating the suitability of niosomal gel for topical and systemic delivery of atenolol.

Keywords: atenolol, chitosan, niosomes, transdermal

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Authors: Mihaela Beregoi, Horia Iovu, Cristina Busuioc, Alexandru Evanghelidis, Elena Matei, Monica Enculescu, Ionut Enculescu

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Nanomaterials field is very attractive for all researchers who are attempting to develop new devices with the same or improved properties than the micro-sized ones, while reducing the reagents and power consumptions. In this way, a wide range of nanomaterials were fabricated and integrated in applications for electronics, optoelectronics, solar cells, tissue reconstruction and drug delivery. Obviously, the most appealing ones are those dedicated to the medical domain. Different types of nano-sized materials, such as particles, fibers, films etc., can be synthesized by using physical, chemical or electrochemical methods. One of these techniques is electrospinning, which enable the production of fibers with nanometric dimensions by pumping a polymeric solution in a high electric field; due to the electrostatic charging and solvent evaporation, the precursor mixture is converted into nonwoven meshes with different fiber densities and mechanical properties. Moreover, polyaniline is a conducting polymer with interesting optical properties, suitable for displays and electrochromic windows. Otherwise, polyaniline is an electroactive polymer that can contract/expand by applying electric stimuli, due to the oxidation/reduction reactions which take place in the polymer chains. These two main properties can be exploited in order to synthesize smart materials that change their dimensions, exhibiting in the same time good electrochromic properties. In the context aforesaid, a poly(methyl metacrylate) solution was spun to get webs composed of fibers with diameter values between 500 nm and 1 µm. Further, the polymer meshes were covered with a gold layer in order to make them conductive and also appropriate as working electrode in an electrochemical cell. The gold shell was deposited by DC sputtering. Such metalized fibers can be transformed into smart materials by covering them with a thin layer of conductive polymer. Thus, the webs were coated with a polyaniline film by the electrochemical route, starting from and aqueous solution of aniline and sulfuric acid, where sulfuric acid acts as oxidant agent. For the polymerization of aniline, a saturated calomel electrode was employed as reference, a platinum plate as counter electrode and the gold covered webs as working electrode. Chronoamperometry was selected as deposition method for polyaniline, by modifying the deposition time. Metalized meshes with different fiber densities were used, the transmission ranging between 70 and 80 %. The morphological investigation showed that polyaniline layer has a granular structure for all deposition experiments. As well, some preliminary optical tests were done by using sulfuric acid as electrolyte, which revealed the modification of polyaniline colour from green to dark blue when applying a voltage. In conclusion, new multilayered materials were obtained by a simple approach: the merge of the electrospinning method benefits with polyaniline chemistry. This synthesis method allows the fabrication of structures with reproducible characteristics, suitable for display or tissue substituents.

Keywords: electrospinning, fibers, smart materials, polyaniline

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Authors: Jong-Min Park, Hyung-Ki Park, Seok Hong Min, Tae Kwon Ha

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Titanium is widely used due to its high specific strength, good biocompatibility, and excellent corrosion resistance. In order to produce titanium powders, it is necessary to melt titanium, and generally it is conducted by an induction heating method using Al₂O₃ ceramic crucible. However, since titanium reacts chemically with Al₂O₃, it is difficult to melt titanium by the induction heating method using Al₂O₃ crucible. To avoid this problem, we studied the chemical stability of the various crucibles such as Al₂O₃, MgO, ZrO₂, and Y₂O₃ crucibles to molten titanium. After titanium lumps (Grade 2, O(oxygen)<0.25wt%) were placed in each crucible, they were heated to 1800℃ with a heating rate of 5 ℃/min, held at 1800℃ for 30 min, and finally cooled to room temperature with a cooling rate of 5 ℃/min. All heat treatments were carried out in high purity Ar atmosphere. To evaluate the chemical stability, thermodynamic data such as Ellingham diagram were utilized, and also Vickers hardness test, microstructure analysis, and EPMA quantitative analysis were performed. As a result, Al₂O₃, MgO and ZrO₂ crucibles chemically reacted with molten titanium, but Y₂O₃ crucible rarely reacted with it.

Keywords: titanium, induction melting, crucible, chemical stability

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Authors: Sarah Fahad Alajmi, Tamer Ezzat Youssef

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Here, we report a simple method for the direct conversion of 6-Nitro-1H-indole into N-substituted indoles via electrochemical dehydrogenative reaction with halogenated reagents under strongly basic conditions through N–R bond formation. The N-protected indoles have been prepared under moderate and scalable electrolytic conditions. The conduct of the reactions was performed in a simple divided cell under constant current without oxidizing reagents or transition-metal catalysts. The synthesized products have been characterized via UV/Vis spectrophotometry, 1H-NMR, and FTIR spectroscopy. A possible reaction mechanism is discussed based on the N-protective products. This methodology could be applied to the synthesis of various biologically active N-substituted indole derivatives.

Keywords: green chemistry, 1H-indole, heteroaromatic, organic electrosynthesis

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Authors: Christofas Stergianos, Jason Atkin, Herve Morvan

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As air traffic increases, more airports are interested in utilizing optimization methods. Many processes happen in parallel at an airport, and complex models are needed in order to have a reliable solution that can be implemented for ground movement operations. The ground movement for aircraft in an airport, allocating a path to each aircraft to follow in order to reach their destination (e.g. runway or gate), is one process that could be optimized. The Quickest Path Problem with Time Windows (QPPTW) algorithm has been developed to provide a conflict-free routing of vehicles and has been applied to routing aircraft around an airport. It was subsequently modified to increase the accuracy for airport applications. These modifications take into consideration specific characteristics of the problem, such as: the pushback process, which considers the extra time that is needed for pushing back an aircraft and turning its engines on; stand holding where any waiting should be allocated to the stand; and runway sequencing, where the sequence of the aircraft that take off is optimized and has to be respected. QPPTW involves searching for the quickest path by expanding the search in all directions, similarly to Dijkstra’s algorithm. Finding a way to direct the expansion can potentially assist the search and achieve a better performance. We have further modified the QPPTW algorithm to use a heuristic approach in order to guide the search. This new algorithm is based on the A-star search method but estimates the remaining time (instead of distance) in order to assess how far the target is. It is important to consider the remaining time that it is needed to reach the target, so that delays that are caused by other aircraft can be part of the optimization method. All of the other characteristics are still considered and time windows are still used in order to route multiple aircraft rather than a single aircraft. In this way the quickest path is found for each aircraft while taking into account the movements of the previously routed aircraft. After running experiments using a week of real aircraft data from Zurich Airport, the new algorithm (A-star QPPTW) was found to route aircraft much more quickly, being especially fast in routing the departing aircraft where pushback delays are significant. On average A-star QPPTW could route a full day (755 to 837 aircraft movements) 56% faster than the original algorithm. In total the routing of a full week of aircraft took only 12 seconds with the new algorithm, 15 seconds faster than the original algorithm. For real time application, the algorithm needs to be very fast, and this speed increase will allow us to add additional features and complexity, allowing further integration with other processes in airports and leading to more optimized and environmentally friendly airports.

Keywords: a-star search, airport operations, ground movement optimization, routing and scheduling

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Authors: Ekpekpo Arthur

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Thin films can either be conductive or dielectric (non-conductive). It is formed through atom/molecules state or formed after decomposing the materials into atomic/molecular scale by physical or chemical processes. In this study, thin films of Lead Sulphide were deposited on glass substrate prepared from lead acetate and thiourea solution using chemical bath deposition (CBD). The glass slides were subjected to the pretreatment by soaking them in a solution of 50% sulphuric acid and 50% nitric acid. Lead sulphide was deposited at different parameters such as deposition time and temperature. The optical properties of the thin films were determined from spectroscopy measurements of absorbance and reflectance. Optical studies show that the band gap of lead sulphide ranges between 0.41 eV to 300K.

Keywords: lead sulphide, spectroscopy, absorbance, reflectance

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Authors: Michella Alnajjar, Frederic Christien, Krzysztof Wolski, Cedric Bosch

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Additive manufacturing (AM) has gained more interest in the past few years because it allows 3D parts often having a complex geometry to be directly fabricated, layer by layer according to a CAD model. One of the AM techniques is the selective laser melting (SLM) which is based on powder bed fusion. In this work, the corrosion resistance of 17-4 PH steel obtained by SLM is investigated. Wrought 17-4 PH steel is a martensitic precipitation hardenable stainless steel. It is widely used in a variety of applications such as aerospace, medical and food industries, due to its high strength and relatively good corrosion resistance. However, the combined findings of X-Ray diffraction and electron backscatter diffraction (EBSD) proved that SLM-ed 17-4 PH steel has a fully ferritic microstructure, more specifically δ ferrite. The microstructure consists of coarse ferritic grains elongated along the build direction, with a pronounced solidification crystallographic texture. These results were associated with the high cooling and heating rates experienced throughout the SLM process (10⁵-10⁶ K/s) that suppressed the austenite formation and produced a 'by-passing' phenomenon of this phase during the numerous thermal cycles. Furthermore, EDS measurements revealed a uniform distribution of elements without any dendritic structure. The extremely high cooling kinetics induced a diffusionless solidification, resulting in a homogeneous elemental composition. Consequently, the corrosion properties of this steel are altered from that of conventional ones. By using electrochemical means, it was found that SLM-ed 17-4 PH is more resistant to general corrosion than the wrought steel. However, the SLM-ed material exhibits metastable pitting due to its high porosity density. In addition, the hydrogen embrittlement of SLM-ed 17-4 PH steel is investigated, and a correlation between its behavior and the observed microstructure is made.

Keywords: corrosion resistance, 17-4 PH stainless steel, selective laser melting, hydrogen embrittlement

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Authors: Robert Kwame Kpaliba, Dennis Kpakpor Adotey, Yaw Serfor-Armah

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Increase in the oceanic carbon dioxide absorbance from the atmosphere due to climate change has led to appreciable change in the chemistry of the oceans. The change in oceanic pH referred to as ocean acidification poses multiple threats and stresses on marine species, biodiversity, goods and services, and livelihoods. Marine ecosystems are continuously threatened by plethora of natural and anthropogenic stressors including carbon dioxide (CO₂) emissions causing a lot of changes which has not been experienced for approximately 60 years. Little has been done in Africa as a whole and Ghana in particular to improve the understanding of the variations of the carbonate chemistry of seawater and the biophysical impacts of ocean acidification on security of seafood, nutrition, climate and environmental change. There is, therefore, the need for regular monitoring of carbonate chemistry of seawater along Ghana’s coastline to generate reliable data to aid marine policy formulation. Samples of seawater were collected thrice every month for a one-year period from five study sites for the various parameters to be analyzed. Analysis of the measured physico-chemical and the carbonate chemistry parameters was done using simple statistics. Correlation test and ANOVA were run on both of the physico-chemical and carbonate chemistry parameters. The carbonate chemistry parameters were measured using computer software programme (CO₂cal v4.0.9) except total alkalinity and pH. The study assessed the variability of seawater carbonate chemistry in selected portions of the Central Atlantic Coastline of Ghana (Tsokomey/Bortianor, Kokrobitey, Gomoa Nyanyanor, Gomoa Fetteh, and Senya Breku landing beaches) over a 1-year period (June 2016–May 2017). For physico-chemical parameters, there was insignificant variation in nitrate (NO₃⁻) (1.62 - 2.3 mg/L), ammonia (NH₃) (1.52 - 2.05 mg/L), and salinity (sal) (34.50 - 34.74 ppt). Carbonate chemistry parameters for all the five study sites showed significant variation: partial pressure of carbon dioxide (pCO₂) (414.08-715.5 µmol/kg), carbonate ion (CO₃²⁻) (115-157.92 µmol/kg), pH (7.9-8.12), total alkalinity (TA) (1711.8-1986 µmol/kg), total carbon dioxide (TCO₂) (1512.1 - 1792 µmol/kg), dissolved carbon dioxide (CO₂aq) (10.97-18.92 µmol/kg), Revelle Factor (RF) (9.62-11.84), aragonite (ΩAr) (0.75-1.48) and calcite (ΩCa) (1.08-2.14). The study revealed that the partial pressure of carbon dioxide and temperature did not have a significant effect on each other (r² = 0.31) (p-value = 0.0717). There was an appreciable effect of pH on dissolved carbon dioxide (r² = 0.921) (p-value = 0.0000). The variation between total alkalinity and dissolved carbon dioxide was appreciable (r² = 0.731) (p-value = 0.0008). There was a significant correlation between total carbon dioxide and dissolved carbon dioxide (r² = 0.852) (p-value = 0.0000). Revelle factor correlated strongly with dissolved carbon dioxide (r² = 0.982) (p-value = 0.0000). Partial pressure of carbon dioxide corresponds strongly with atmospheric carbon dioxide (r² = 0.9999) (p-value = 0.00000).

Keywords: carbonate chemistry, seawater, central atlantic coastline, Ghana, ocean acidification

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Authors: Asima Shah, F. A. Masoodi, Adil Gani, Bilal Ahmad Ashwar

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The present study was designed to evaluate the effect of γ-rays on the antioxidant and antiproliferative potential of β-glucan isolated from oats. The β-glucan was irradiated with 0, 2, 6, and 10 kGy by gamma ray. The samples were characterized by FT-IR, GPC, and quantitative estimation by Megazyme β-glucan assay kit. The average molecular weight of non-irradiated β-glucan was 199 kDa that decreased to 70 kDa at 10 kGy. Both FT-IR spectrum and chemical analysis revealed that the extracted β-glucan was pure having minor impurities. Antioxidant activity was evaluated by DPPH, lipid peroxidation, reducing power, metal chelating ability and oxidative DNA damage assays. Results revealed that the antioxidant activity of β-glucan increased with the increase in irradiation dose. Irradiated β-glucan also exhibited dose dependent cancer cell growth inhibition with irradiation doses. The study revealed that low molecular weight β-glucan with enhanced antioxidant and antiproliferative activities can be produced by a simple irradiation method.

Keywords: γ-irradiation, antioxidant activity, antiproliferative activity, β-glucan, oats

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Authors: Ramesh Kumar, Rajesh Kumar, Shaktiman Singh, Atar Singh, Anshuman Bhardwaj, Ravindra Kumar Sinha, Anupma Kumari

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A detailed study of the ion chemistry of the Shaune Garnag glacier meltwater has been carried out to assess the role of active glacier in the chemical denudation rate. The chemical compositions of various ions in meltwater of the Shaune Garang glacier were analyzed during the melting period 2015 and 2016. Total 112 of melt water samples twice in a day were collected during ablation season of 2015 and 2016. To identify various factors controlling the dissolved ionic strength of Shaune Garang Glacier meltwater statistical analysis such as correlation matrix, Principle Component Analysis (PCA) and factor analysis were applied to deduce the result. Cation concentration for Ca²⁺ > Mg²⁺ > Na⁺ > K⁺ in the meltwater for both the years can be arranged in the order as Ca²⁺ > Mg²⁺ > Na⁺ > K⁺. Study showed that Ca²⁺ and HCO₃⁻ found to be dominant on the both melting period. Carbonate weathering identified as the dominant process controlling the dissolved ion chemistry of meltwater due to the high ratios of (Ca²⁺ + Mg²⁺) versus TZ+ and (Ca²⁺ + Mg²⁺) versus (Na⁺ + K⁺) in the study area. The cation denudation rate of the Shaune Garnag catchment is 3412.2 m⁻² a⁻¹, i.e. higher than the other glacierised catchment in the Himalaya, indicating intense chemical erosion in this catchment.

Keywords: Shaune Garang glacier, Hydrochemistry, chemical composition, cation denudation rate, carbonate weathering

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Authors: Pratikno Hidayat, Khamdan Cahyari

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Hydrogen is the ultimate choice of energy carriers in future. It contents high energy density (42 kJ/g), emits only water vapor during combustion and has high energy conversion up to 50% in fuel cell application. One of the promising methods to produce hydrogen is from organic waste through dark fermentation method. It utilizes sugar-rich organic waste as substrate and hydrogen-producing microorganisms to generate the hydrogen. Solid waste of sago processing industries in Indonesia is one of the promising raw materials for both producing biofuel hydrogen and mitigating the environmental impact due to the waste disposal. This research was meant to investigate the effect of chemical and biological pretreatment i.e. acid treatment and mushroom cultivation toward lignocellulosic waste of these sago industries. Chemical pretreatment was conducted through exposing the waste into acid condition using sulfuric acid (H2SO4) (various molar i.e. 0.2, 0.3, and 0.4 M and various duration of exposure i.e. 30, 60 and 90 minutes). Meanwhile, biological treatment was conducted through utilization of the solid waste as growth media of mushroom (Oyster and Ling-zhi) for 3 months. Dark fermentation was conducted at pH 5.0, temperature 27℃ and atmospheric pressure. It was noticed that chemical and biological pretreatment could improve hydrogen yield with the highest yield at 3.8 ml/g VS (31%v H2). The hydrogen production was successfully performed to generate high percentage of hydrogen, although the yield was still low. This result indicated that the explosion of acid chemical and biological method might need to be extended to improve degradability of the solid waste. However, high percentage of hydrogen was resulted from proper pretreatment of residual sludge of biogas plant to generate hydrogen-producing inoculum.

Keywords: hydrogen, sago waste, chemical, biological, dark fermentation, Indonesia

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Authors: Joo-Heon Lee, Seo-Yeon Park, Chanyang Sur, Ho-Won Jang

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Satellite-based remote sensing technique has been widely used in the area of drought and environmental monitoring to overcome the weakness of in-situ based monitoring. There are many advantages of remote sensing for drought watch in terms of data accessibility, monitoring resolution and types of available hydro-meteorological data including environmental areas. This study was focused on the applicability of drought monitoring based on satellite imageries by applying to the historical drought events, which had a huge impact on meteorological, agricultural, and hydrological drought. Satellite-based drought indices, the Standardized Precipitation Index (SPI) using Tropical Rainfall Measuring Mission (TRMM) and Global Precipitation Mission (GPM); Vegetation Health Index (VHI) using MODIS based Land Surface Temperature (LST), and Normalized Difference Vegetation Index (NDVI); and Scaled Drought Condition Index (SDCI) were evaluated to assess its capability to analyze the complex topography of the Korean peninsula. While the VHI was accurate when capturing moderate drought conditions in agricultural drought-damaged areas, the SDCI was relatively well monitored in hydrological drought-damaged areas. In addition, this study found correlations among various drought indices and applicability using Receiver Operating Characteristic (ROC) method, which will expand our understanding of the relationships between hydro-meteorological variables and drought events at global scale. The results of this research are expected to assist decision makers in taking timely and appropriate action in order to save millions of lives in drought-damaged areas.

Keywords: drought monitoring, moderate resolution imaging spectroradiometer (MODIS), remote sensing, receiver operating characteristic (ROC)

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Authors: Yang Li, Mingkai Liu, Qiong Rao, Zhongrui Gai, Ying Pan, Hongguang Jin

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Hydrogen is an ideal and potential energy carrier due to its high energy efficiency and low pollution. An alternative and promising approach to hydrogen generation is the chemical looping steam reforming of methane (CL-SRM) over iron-based oxygen carriers. However, the process faces challenges such as high reaction temperature (>850 ℃) and low methane conversion. We demonstrate that Ni-mixed Fe-based oxygen carrier particles have significantly improved the methane conversion and hydrogen production rate in the range of 450-600 ℃ under atmospheric pressure. The effect on the reaction reactivity of oxygen carrier particles mixed with different Ni-based particle mass ratios has been determined in the continuous unit. More than 85% of methane conversion has been achieved at 600 ℃, and hydrogen can be produced in both reduction and oxidation steps. Moreover, the iron-based oxygen carrier particles exhibited good cyclic performance during 150 consecutive redox cycles at 600 ℃. The mid-temperature iron-based oxygen carrier particles, integrated with a moving-bed chemical looping system, might provide a powerful approach toward more efficient and scalable hydrogen production.

Keywords: chemical looping, hydrogen production, mid-temperature, oxygen carrier particles

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Authors: Christodoulou Christos, Politis Anastasios

Abstract:

A large majority of users favoured to wireless LAN connection since it was so simple to use. A wireless network can be the target of numerous attacks. Class hijacking is a well-known attack that is fairly simple to execute and has significant repercussions on users. The statistical flow analysis based on machine learning (ML) techniques is a promising categorization methodology. In a given dataset, which in the context of this paper is a collection of components representing frames belonging to various flows, machine learning (ML) can offer a technique for identifying and characterizing structural patterns. It is possible to classify individual packets using these patterns. It is possible to identify fraudulent conduct, such as class hijacking, and take necessary action as a result. In this study, we explore a way to use machine learning approaches to thwart this attack.

Keywords: wireless lan, quality of service, machine learning, class hijacking, EDCA remapping

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Authors: Ben Salah Nahla

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The problem of water in Tunisia affects the quality and quantity. Tunisia is in a situation of water shortage. It was estimated that 4.6 Mm3/an. Moreover, the quality of water in Tunisia is also mediocre. In fact, 50% of the water has a high salinity (> 1.5g/l). There are several parameters which affect water quality such as sodium, fluoride. An excess of this parameter may induce some human health. Furthermore, the mining basin area has a problem of industrial waste. This problem may affect the water quality of the groundwater. Therefore, the purpose of this work is to assess the water quality in Basin Mining and the impact of fluorine. For this research, some water samples were done in the field and specific water analysis was implemented in the laboratory. Sampling is carried out on eight drilling in the area of the mining region. In the following, we will look at water view composition, physical and chemical quality. A physical-chemical analysis of water from a survey of the Mining area of Tunisia was performed and showed an excess for the following items: fluorine, sodium, sulfate. So many chemicals may be present in water. However, only a small number of them immediately concern in terms of health in all circumstances. Fluorine (F) is one particular chemical that is considered both necessary for the human body, but an excess of the rate of this chemical causes serious diseases. Sodium fluoride and sodium silicofluoride are more soluble and may spread in animals and plants where their toxicity largest organizations. The more complex particles such as cryolite and fluorite, almost insoluble, are more stable and less toxic. Thereafter, we will study the problem of excess fluorine in the water. The latter intended for human consumption must always comply with the limits for microbiological quality parameters and physical-chemical parameters defined by European standards (1.5 mg/l) and Tunisian (2 mg/l).

Keywords: water, minier basin, fluorine, silicofluoride

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Authors: Nursel Koyuncu, Nihal Ata Tutkun

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Frailty model is a survival model that takes into account the unobserved heterogeneity for exploring the relationship between the survival of an individual and several covariates. In the recent years, proposed survival models become more complex and this feature causes convergence problems especially in large data sets. Therefore selection of sample from these big data sets is very important for estimation of parameters. In sampling literature, some authors have defined new sampling schemes to predict the parameters correctly. For this aim, we try to see the effect of sampling design in semi-parametric frailty model. We conducted a simulation study in R programme to estimate the parameters of semi-parametric frailty model for different sample sizes, censoring rates under classical simple random sampling and ranked set sampling schemes. In the simulation study, we used data set recording 17260 male Civil Servants aged 40–64 years with complete 10-year follow-up as population. Time to death from coronary heart disease is treated as a survival-time and age, systolic blood pressure are used as covariates. We select the 1000 samples from population using different sampling schemes and estimate the parameters. From the simulation study, we concluded that ranked set sampling design performs better than simple random sampling for each scenario.

Keywords: frailty model, ranked set sampling, efficiency, simple random sampling

Procedia PDF Downloads 211

Authors: Iyagbaye O. Rich, Omoigberale O. Michael, Iyagbaye A. Louis

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The physical, chemical parameters and some trace contents of Ugbogui in Edo State, Nigeria were investigated from August 2015 to April 2016. Four stations were studied from upstream to downstream using standard methods. A total of thirty-three (33) physical and chemical characteristics and trace metal contents were examined; Air and water temperatures, depth, transparency, colour, turbidity, flow velocity, pH, total alkalinity, conductivity and dissolved solids etc. Other includes dissolved oxygen, oxygen saturation, biochemical oxygen demand, chloride, phosphate, sodium, nitrate, sulphate, potassium, calcium, magnesium, iron, lead, copper, zinc, nickel, cadmium, vanadium and chromium. Eleven (11) parameters exhibited clear seasonal variations. However, there were high significant differences (p < 0.01) in the values of depth, colour, total suspended solid, biochemical oxygen demand, chemical oxygen demand, chloride, bicarbonate, phosphate, sulphate, iron, manganese, zinc, copper, chromium and cadmium among the stations. The anthropogenic activities had negatively impacted at station 3 of the river, although most of the recorded values were still within permissible limits.

Keywords: anthropogenic activities, Nigeria, permissible limits, physical and chemical parameters, trace metal, water quality

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Authors: Hertzog Clara, Sakurai Sho, Hirota Koichi, Nojima Takuya

Abstract:

It is common to see graphics appearing on television while watching a sports game to provide information, but it is less common to see graphics specifically aiming to boost spectators’ dynamism perception. It is even less common to see such graphics designed especially for virtual reality (VR). However, it appears that even with simple dynamic graphics, it would be possible to improve VR sports spectators’ experience. So, in this research, we explain how graphics can be used in VR to improve the dynamism of a broadcasted sports game and we provide a simple example. This example consists in a white halo displayed around the video and blinking according to the game speed. We hope to increase people’s awareness about VR sports spectating and the possibilities this display offers through dynamic graphics.

Keywords: broadcasting, graphics, sports spectating, virtual reality

Procedia PDF Downloads 90

Authors: Andreea Cârâc, Elena Morosan, Ana Corina Ionita, Rica Bosencu, Geta Carac

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Lanthanum carbonate exhibits a considerable ability to bind phosphate and the substitution of Ca2+ ions by divalent or trivalent lanthanide metal ions attracted attention during the past few years. Although Lanthanum carbonate has not been approved by the FDA for treatment of hyperphosphatemia, we prospectively evaluated the efficacy of the combination of Calcium hydroxyapatite and Lanthanum carbonate for the treatment of hyperphosphatemia on mice. Calcium hydroxyapatite commonly referred as CHAp is a bioceramic material and is one of the most important implantable materials due to its biocompatibility and osteoconductivity. We prepared calcium hydroxyapatite and lanthanum carbonate. CHAp was prepared by co-precipitation method using Ca(OH)2, H3PO4, NH4OH with calcination at 1200ºC. Lanthanum carbonate was prepared by chemical method using NaHCO3 and LaCl3 at low pH environment , ph below 4.0 The confirmation of both substances structures was made using XRD characterization, FTIR spectra and SEM /EDX analysis. The study group included 20 subjects-mice divided into four groups according to the administered substance: lanthanum carbonate (group A), lanthanum carbonate + CHAp (group B), CHAp (group C) and salt water (group D). The results indicate a phosphate decrease when subjects (mice) were treated with CHAp and lanthanum carbonate (0.5 % CMC), in a single dose of 1500 mg/kg. Serum phosphate concentration decreased [from 4.5 ± 0.8 mg/dL) to 4.05 ± 0.2 mg/dL), P < 0.01] in group A and to 3.6 ± 0.2 mg/dL] only after the 24 hours of combination therapy. The combination of CHAp and lanthanum carbonate is a suitable regimen for hyperphosphatemia treatment subjects because it avoids both the hypercalcemia of CaCO3 and the adverse effects of CHAp. The ability of CHAp to decrease the serum phosphate concentration is 1/3 that of lanthanum carbonate.

Keywords: calcium hydroxyapatite, hyperphosphatemia, lanthanum carbonate, phosphate, structures

Procedia PDF Downloads 378

Authors: Ahmed Nouasri, Tahar Dob, Toumi Mohamed, Dahmane Dahmane, Soumioa Krimat, Lynda Lamari, Chabane Chelghom

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The aim of this study is to investigate the chemical composition for the first time, and antimicrobial activities of essential oil (EO) of Thymus lanceolatus Desf., an endemic thyme from Tiaret province of Algeria. The chemical composition of hydrodistilled essential oil from flowering aerial parts has been analyzed by GC and GC/MS techniques, the antimicrobial activity was realised by agar disc diffusion method and MIC was determined in solid medium by direct contact. Essential oil of T. lanceolataus has been yielded of 2.336 (w/w) based on dry weight, the analyses cited above, led to the identification of 29 components, which accounted for 97.34% of the total oil. Oxygenated monoterpenes was the main fraction (88.31%) dominated by thymol (80.2%) as major component of this oil, followed by carvacrol (6.25%). The oil was found effective against all tested strains especially fungus, except Pseudomonas aeruginosa were low activity observed, in addition Gram (+) bacteria found to be more sensitive to the EO than Gram (-) bacteria. This activity was ranging from12±2.65mm to 60.00±0.00mm Ø, with the lowest MIC value of under 0.06mg/ml to 12.53mg/ml. This results provided the evidence that the studied plant might indeed be potential sources of natural antimicrobial agents

Keywords: Thymus lanceolatus Desf., essential oil, chemical composition, antimicrobial activities

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Authors: Anjan Hazra, Nirjhar Dasgupta, Chandan Sengupta, Sauren Das

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Tea (Camellia sinensis) has received substantial attention from the scientific world time to time, not only for its commercial importance, but also for its demand to the health-conscious people across the world for its extensive use as potential sources of antioxidant supplement. These health-benefit traits primarily rely on some regulatory networks of different metabolic pathways. Development of microsatellite markers from the conserved genomic regions is being worthwhile for studying the genetic diversity of closely related species or self-pollinated species. Although several SSR markers have been reported, in tea the trait-specific Simple Sequence Repeats (SSRs) are yet to be identified, which can be used for marker assisted breeding technique. MicroRNAs are endogenous, noncoding, short RNAs directly involved in regulating gene expressions at the post-transcriptional level. It has been found that diversity in miRNA gene interferes the formation of its characteristic hair pin structure and the subsequent function. In the present study, the precursors of small regulatory RNAs (microRNAs) has been fished out from tea Expressed Sequence Tag (EST) database. Furthermore, the simple sequence repeat motifs within the putative miRNA precursor genes are also identified in order to experimentally validate their existence and function. It is already known that genic-SSR markers are very adept and breeder-friendly source for genetic diversity analysis. So, the potential outcome of this in-silico study would provide some novel clues in understanding the miRNA-triggered polymorphic genic expression controlling specific metabolic pathways, accountable for tea quality.

Keywords: micro RNA, simple sequence repeats, tea quality, trait specific marker

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Authors: Yasemin Seki, Aysun Akşit

Abstract:

The goal of this research is to modify the surface characterization of jute yarns with different chemical agents to improve the compatibility with a non-polar polymer, polypropylene, when used as reinforcement. A literature review provided no knowledge on surface treatment of jute fibers with sodium perborate trihydrate. This study also aims to compare the efficiency of sodium perborate trihydrate on jute fiber treatment with other commonly used chemical agents. Accordingly, jute yarns were treated with 0.02% potassium dichromate (PD), potassium permanganate (PM) and sodium perborate trihydrate (SP) aqueous solutions in order to enhance interfacial compatibility with polypropylene in this study. The effect of treatments on surface topography, surface chemistry and interfacial shear strength of jute yarns with polypropylene were investigated. XPS results revealed that surface treatments enhanced surface hydrophobicity by increasing C/O ratios of fiber surface. Surface roughness values increased with the treatments. The highest interfacial adhesion with polypropylene was achieved after SP treatment by providing the highest surface roughness values and hydrophobic character of jute fiber.

Keywords: jute, chemical modification, sodium perborate, polypropylene

Procedia PDF Downloads 508