Search results for: electrochemical hydrogen storage

Authors: Vinu Viswanath, Lawrence Dsouza, Ugo Ravon

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Syngas typically and intermediary gas product has a wide range of application of producing various chemical products, such as mixed alcohols, hydrogen, ammonia, Fischer-Tropsch products methanol, ethanol, aldehydes, alcohols, etc. There are several technologies available for the syngas production. An alternative to the conventional processes an attractive route of utilizing carbon dioxide and methane in equimolar ratio to generate syngas of ratio close to one has been developed which is also termed as Dry Reforming of Methane technology. It also gives the privilege to utilize the greenhouse gases like CO2 and CH4. The dry reforming process is highly endothermic, and indeed, ΔG becomes negative if the temperature is higher than 900K and practically, the reaction occurs at 1000-1100K. At this temperature, the sintering of the metal particle is happening that deactivate the catalyst. However, by using this strategy, the methane is just partially oxidized, and some cokes deposition occurs that causing the catalyst deactivation. The current research work was focused to mitigate the main challenges of dry reforming process such coke deposition, and metal sintering at high temperature.To achieve these objectives, we employed three different strategies of catalyst development. 1) Use of bulk catalysts such as olivine and pyrochlore type materials. 2) Use of metal doped support materials, like spinel and clay type material. 3) Use of core-shell model catalyst. In this approach, a thin layer (shell) of redox metal oxide is deposited over the MgAl2O4 /Al2O3 based support material (core). For the core-shell approach, an active metal is been deposited on the surface of the shell. The shell structure formed is a doped metal oxide that can undergo reduction and oxidation reactions (redox), and the core is an alkaline earth aluminate having a high affinity towards carbon dioxide. In the case of metal-doped support catalyst, the enhanced redox properties of doped CeO2 oxide and CO2 affinity property of alkaline earth aluminates collectively helps to overcome coke formation. For all of the mentioned three strategies, a systematic screening of the metals is carried out to optimize the efficiency of the catalyst. To evaluate the performance of them, the activity and stability test were carried out under reaction conditions of temperature ranging from 650 to 850 ̊C and an operating pressure ranging from 1 to 20 bar. The result generated infers that the core-shell model catalyst showed high activity and better stable DR catalysts under atmospheric as well as high-pressure conditions. In this presentation, we will show the results related to the strategy.

Keywords: carbon dioxide, dry reforming, supports, core shell catalyst

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Authors: Oiane Ruiz de Azua, Salvador Borros, Nuria Agullo, Jordi Arbusa

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Tackiness is described as the ability to spontaneously form a bond to another material under light pressures within a short application time. During the first few minutes of the adhesive's curing, it is necessary to have enough tack to keep the substrates together while cohesion is increasing within the adhesive. This property plays a key role in the manufacturing process of pieces. Epoxy adhesives, unlike other adhesives, usually present low tackiness before curing; however, there is very little literature about the use of tackifiers in epoxy adhesives, except for the high molecular weight epoxy additives. In the present work, a tetrafunctional epoxy resin based on Bisphenol-A and Sulfanilamide has been synthesized in order to be used as a tackifier. This additive offers improved specific adhesion to two-component (2K) epoxy adhesives. The dosage of the tackifier has to be done carefully not to alter the mechanical and rheological properties of the adhesive. The synthetized product has been analyzed by FTIR and ¹H-NMR analysis, and the effect of the addition of 1 wt % of the tackifier on rheological properties, viscoelastic behavior, and mechanical properties has been studied. On one hand, the addition of the product in the epoxy resin part showed a significant increase in tackiness regarding the neat epoxy resin. On the other hand, tackiness of the whole formulation was also increased. Curing time of the adhesive has not undergone any relevant changes with the tackifier addition. Regarding viscoelastic properties, Storage Modulus (G') and Loss Modulus (G'') remain also unchanged at ambient temperature. Probably, in case higher tackifier concentration would be added, differences in viscoelastic properties would be observed. The study of mechanical properties shows that hardness and tensile strength also keep their values unchanged regarding neat two component adhesive. In conclusion, the addition of 1 wt % of sulfanilamide/epoxy enhanced the tackiness of the epoxy resin part, improves tack without modifying significantly either the rheological, the mechanical, or the viscoelastic properties of the product. Thus, the sulfanilamide presented could be a good candidate to be used as an additive to the 2k epoxy formulation for the manufacturing process of pieces.

Keywords: epoxy adhesive, manufacturing process of pieces, sulfanilamide, tackifiers

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Authors: Ife Elegbeleye, Nnditshedzeni Eric, Regina Maphanga, Femi Elegbeleye, Femi Agunbiade

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The global potential of other renewable energy sources such as wind, hydroelectric, bio-mass, and geothermal is estimated to be approximately 13 %, with hydroelectricity constituting a larger percentage. Sunlight provides by far the largest of all carbon-neutral energy sources. More energy from the sunlight strikes the Earth in one hour (4.3 × 1020 J) than all the energy consumed on the planet in a year (4.1 × 1020 J), hence, solar energy remains the most abundant clean, renewable energy resources for mankind. Photovoltaic (PV) devices such as silicon solar cells, dye sensitized solar cells are utilized for harnessing solar energy. Polyene-diphenylaniline organic molecules are important sets of molecules that has stirred many research interest as photosensitizers in TiO₂ semiconductor-based dye sensitized solar cells (DSSCs). The advantages of organic dye molecule over metal-based complexes are higher extinction coefficient, moderate cost, good environmental compatibility, and electrochemical properties. The polyene-diphenylaniline organic dyes with basic configuration of donor-π-acceptor are affordable, easy to synthesize and possess chemical structures that can easily be modified to optimize their photocatalytic and spectral properties. The enormous interest in polyene-diphenylaniline dyes as photosensitizers is due to their fascinating spectral properties which include visible light to near infra-red-light absorption. In this work, density functional theory approach via GPAW software, Avogadro and ASE were employed to study the effect of methoxy functionalized group on the spectral properties of polyene-diphenylaniline dyes and their photons absorbing characteristics in the visible region to near infrared region of the solar spectrum. Our results showed that the two-phenyl based complexes D5 and D7 exhibits maximum absorption peaks at 750 nm and 850 nm, while D9 and D11 with methoxy group shows maximum absorption peak at 800 nm and 900 nm respectively. The highest absorption wavelength is notable for D9 and D11 containing additional polyene and methoxy groups. Also, D9 and D11 chromophores with the methoxy group shows lower energy gap of 0.98 and 0.85 respectively than the corresponding D5 and D7 dyes complexes with energy gap of 1.32 and 1.08. The analysis of their electron injection kinetics ∆Ginject into the band gap of TiO₂ shows that D9 and D11 with the methoxy group has higher electron injection kinetics of -2.070 and -2.030 than the corresponding polyene-diphenylaniline complexes without the addition of polyene group with ∆Ginject values of -2.820 and -2.130 respectively. Our findings suggest that the addition of functionalized group as an extension of the organic complexes results in higher light harvesting efficiencies and bathochromic shift of the absorption spectra to higher wavelength which suggest higher current densities and open circuit voltage in DSSCs. The study suggests that the photocatalytic properties of organic chromophores/complexes with donor-π-acceptor configuration can be enhanced by the addition of functionalized groups.

Keywords: renewable energy resource, solar energy, dye sensitized solar cells, polyene-diphenylaniline organic chromophores

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Authors: Juan José Mesas, Luis Sainz

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The motivation for the development of this paper lies in the need for energy networks to reduce losses, improve performance, optimize their operation and try to benefit from the interconnection capacity with other networks enabled for other energy carriers. These interconnections generate interdependencies between some energy networks and others, which requires suitable models and methods for their analysis. Traditionally, the modeling and study of energy networks have been carried out independently for each energy carrier. Thus, there are well-established models and methods for the steady-state analysis of electrical networks, gas networks, and thermal networks separately. What is intended is to extend and combine them adequately to be able to face in an integrated way the steady-state analysis of networks with multiple energy carriers. Firstly, the added value of multi-energy networks, their operation, and the basic principles that characterize them are explained. In addition, two current aspects of great relevance are exposed: the storage technologies and the coupling elements used to interconnect one energy network with another. Secondly, the characteristic equations of the different energy networks necessary to carry out the steady-state analysis are detailed. The electrical network, the natural gas network, and the thermal network of heat and cold are considered in this paper. After the presentation of the equations, a particular case of the steady-state analysis of a specific multi-energy network is studied. This network is represented graphically, the interconnections between the different energy carriers are described, their technical data are exposed and the equations that have previously been presented theoretically are formulated and developed. Finally, the two iterative numerical resolution methods considered in this paper are presented, as well as the resolution procedure and the results obtained. The pros and cons of the application of both methods are explained. It is verified that the results obtained for the electrical network (voltages in modulus and angle), the natural gas network (pressures), and the thermal network (mass flows and temperatures) are correct since they comply with the distribution, operation, consumption and technical characteristics of the multi-energy network under study.

Keywords: coupling elements, energy carriers, multi-energy networks, steady-state analysis

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Authors: Rameh Chauhan

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Tunnel construction in Himalayan rock is a challenging task due to fragile nature of the strata. Tunnel excavation carried out from lower Himalayas to high Himalayas in different metamorphic rock. Therefore application of engineering geology plays a vital role during various stage of the tunneling projects. Engineering geology is defined as application of geology to construction of civil structures through engineering practice. It is applied to the design, construction and performance aspects of engineering structure on the surface or sub-surface like dam, underground and surface power house, cut slopes, tunnels and underground storage cavern for nuclear material. But this paper emphasized mostly on underground structures like big caverns of Power house, desilting chambers, and tunnels of various sizes. Construction of these structures in the fragile rock conditions of Himalayan geology from Western Himalayas to Eastern Himalayas necessitated the application of the engineering geology on the micro-scale base for the stability, performance, and longevity of the civil structures. Number of hydropower projects have been constructed, some of them are under construction and under investigation stage. These projects are located in various parts of Himalayas under various seismic-tectonic zones. Tunneling works are involved in these projects. This paper represents the various engineering geological practices adopted in investigation and construction stage of various projects based on experiences gained during past construction histories in Himalayan geology of young mountains in very fragile geological conditions. Highlighting and sharing of use of these techniques on various platforms will definitely enhance the knowledge for carrying out the construction of various projects for the development of society. Construction of the tunnels, surface, and sub-surface caverns, dams, highway, metro, highway tunnels are all based on engineering geological parameters in combinations with other engineering considerations.

Keywords: cavern-power house, desilting chambers and tunnels, seismic-tectonic-zones, earthquake-prone zones based on intensities

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Authors: Muhammad Nouman, Fahad Tiwana, Muhammad Irfan, Mohsin Tiwana

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Traffic congestion has been increasing significantly in major metropolitan areas as a result of increased motorization, urbanization, population growth and changes in the urban density. Traffic congestion compromises efficiency of transport infrastructure and causes multiple traffic concerns; including but not limited to increase of travel time, safety hazards, air pollution, and fuel consumption. Traffic management has become a serious challenge for federal and provincial governments, as well as exasperated commuters. Effective, flexible, efficient and user-friendly traffic information/database management systems characterize traffic conditions by making use of traffic counts for storage, processing, and visualization. While, the emerging data collection technologies continue to proliferate, its accuracy can be guaranteed through the comparison of observed data with the manual handheld counters. This paper presents the design of tablet based manual traffic counting application and framework for development of traffic database management system for Pakistan. The database management system comprises of three components including traffic counting android application; establishing online database and its visualization using Google maps. Oracle relational database was chosen to develop the data structure whereas structured query language (SQL) was adopted to program the system architecture. The GIS application links the data from the database and projects it onto a dynamic map for traffic conditions visualization. The traffic counting device and example of a database application in the real-world problem provided a creative outlet to visualize the uses and advantages of a database management system in real time. Also, traffic data counts by means of handheld tablet/ mobile application can be used for transportation planning and forecasting.

Keywords: manual count, emerging data sources, traffic information quality, traffic surveillance, traffic counting device, android; data visualization, traffic management

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Authors: Jonathan A. Akinwale, Ibukun J. Agotola

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There is a need to rethink how technology is being disseminated to end users in order to ensure wide adoption and utilisation. Aflasafe bio-control was developed to combat aflatoxin in maize to ensure food safety for the end users. This study was designed to assess how the pull mechanism is enhancing the utilisation of this proven technology among maize farmers in Oyo State, Nigeria. The study determines the awareness of farmers on Aflasafe, sources of purchase of Aflasafe, incentives towards the usage of Aflasafe, constraints to farmers’ utilisation and factors influencing farmers’ utilisation of Aflasafe bio-control measures. Respondents were selected using a multi-stage sampling procedure. Data were collected from respondents through interview schedule and analyzed using descriptive statistics (means, frequencies, and percentages) and inferential statistics (Pearson Product Moment Correlation and regression analysis). The result showed that 89% of the farmers indicated implementers as the outlet for the purchase of Aflasafe. Also, premium payment and provision of technical assistance were the highly ranked incentives to the utilisation of Aflasafe among the farmers. The study also revealed that the major constraints face by respondents were low access to credit facility, inadequate sources of purchase, and lack of storage facilities. A little above half (54%) of the farmers were found to have fully utilized Aflasafe in maize production. Pearson Product Moment Correlation (PPMC) analysis revealed that there was a significant correlation between incentives and utilisation of Aflasafe (r-value=0.274; p ≤ 0.01). The result of the regression analysis indicated maize production experience (β=0.572), output (β=0.531), years of formal education (β=0.404) and household size (β=0.391) as the leading factors influencing farmers utilisation of Aflasafe bio-control in maize production. The study, therefore, recommends that governments and non-governmental organisations should be interested in making Aflasafe available to the maize farmers either through loan provision or price subsidy.

Keywords: Aflasafe bio-control, maize production, production incentives, pull mechanism, utilisation

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Authors: David X. Dong, Qingming Zhang, Meng Lu

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Nitrites enter waterways as runoff from croplands and are discharged from many industrial sites. Excessive nitrite inputs to water bodies lead to eutrophication. On-site rapid detection of nitrite is of increasing interest for managing fertilizer application and monitoring water source quality. Existing methods for detecting nitrites use spectrophotometry, ion chromatography, electrochemical sensors, ion-selective electrodes, chemiluminescence, and colorimetric methods. However, these methods either suffer from high cost or provide low measurement accuracy due to their poor selectivity to nitrites. Therefore, it is desired to develop an accurate and economical method to monitor nitrites in environments. We report a low-cost optical sensor, in conjunction with a machine learning (ML) approach to enable high-accuracy detection of nitrites in water sources. The sensor works under the principle of measuring molecular absorptions of nitrites at three narrowband wavelengths (295 nm, 310 nm, and 357 nm) in the ultraviolet (UV) region. These wavelengths are chosen because they have relatively high sensitivity to nitrites; low-cost light-emitting devices (LEDs) and photodetectors are also available at these wavelengths. A regression model is built, trained, and utilized to minimize cross-sensitivities of these wavelengths to the same analyte, thus achieving precise and reliable measurements with various interference ions. The measured absorbance data is input to the trained model that can provide nitrite concentration prediction for the sample. The sensor is built with i) a miniature quartz cuvette as the test cell that contains a liquid sample under test, ii) three low-cost UV LEDs placed on one side of the cell as light sources, with each LED providing a narrowband light, and iii) a photodetector with a built-in amplifier and an analog-to-digital converter placed on the other side of the test cell to measure the power of transmitted light. This simple optical design allows measuring the absorbance data of the sample at the three wavelengths. To train the regression model, absorbances of nitrite ions and their combination with various interference ions are first obtained at the three UV wavelengths using a conventional spectrophotometer. Then, the spectrophotometric data are inputs to different regression algorithm models for training and evaluating high-accuracy nitrite concentration prediction. Our experimental results show that the proposed approach enables instantaneous nitrite detection within several seconds. The sensor hardware costs about one hundred dollars, which is much cheaper than a commercial spectrophotometer. The ML algorithm helps to reduce the average relative errors to below 3.5% over a concentration range from 0.1 ppm to 100 ppm of nitrites. The sensor has been validated to measure nitrites at three sites in Ames, Iowa, USA. This work demonstrates an economical and effective approach to the rapid, reagent-free determination of nitrites with high accuracy. The integration of the low-cost optical sensor and ML data processing can find a wide range of applications in environmental monitoring and management.

Keywords: optical sensor, regression model, nitrites, water quality

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Authors: Abdullah Al-Nassri, Ahmed Al-Alawi

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Seaweeds are classified into three groups: red, green, and brown. Each group of seaweeds consists of several types that have differences in composition. Even at the species level, there are differences in some ingredients, although in general composition, they are the same. Environmental conditions, availability of nutrients, and maturity stage are the main reasons for composition differences. In this study, two red seaweed species, Melanothamnus somalensis & Gelidium omanense, were collected in September 2021 from Sadh (Dhofar governorate, Oman). Five organic solvents were used sequentially to achieve extraction. The solvents were applied in the following order: hexane, dichloromethane, ethyl acetate, acetone, and methanol. Preparative HPLC (PrepLC) was performed to fraction the extracts. The chemical composition was measured; also, total phenols, flavonoids, and tannins were investigated. The structure of the extracts was analyzed by Fourier-transform infrared spectroscopy (FTIR). Seaweeds demonstrated high differences in terms of chemical composition, total phenolic content (TPC), total flavonoid content (TFC), and total tannin content (TTC). Gelidium omanense showed high moisture content, lipid content and carbohydrates (9.8 ± 0.15 %, 2.29 ± 0.09 % and 70.15 ± 0.42 %, respectively) compared to Melanothamnus somalensis (6.85 ± 0.01 %, 2.05 ± 0.12 % and 52.7 ± 0.36 % respectively). However, Melanothamnus somalensis showed high ash content and protein (27.68 ± 0.40 % and 52.7 ± 0.36 % respectively) compared to Gelidium omanense (8.07 ± 0.39 % and 9.70 ± 0.22 % respectively). Melanothamnus somalensis showed higher elements and minerals content, especially sodium and potassium. This is attributed to the jelly-like structure of Melanothamnus somalensis, which allows storage of more solutes compared to the leafy-like structure of Gelidium omanense. Furthermore, Melanothamnus somalensis had higher TPC in all fractions except the hexane fraction than Gelidium omanense. Except with hexane, TFC in the other solvents’ extracts was significantly different between Gelidium omanense and Melanothamnus somalensis. In all fractions, except dichloromethane and ethyl acetate fractions, there were no significant differences in TTC between Gelidium omanense and Melanothamnus somalensis. FTIR spectra showed variation between fractions, which is an indication of different functional groups.

Keywords: chemical composition, organic extract, Omani seaweeds, biological activity, FTIR

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Authors: Mst. Nilufa Sultana, Shatirah Akib, Muhammad Aqeel Ashraf, Mohamed Roseli Zainal Abidin

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Most people today are aware that global Climate change, is not just a scientific theory but also a fact with worldwide consequences. Global climate change is due to rapid urbanization, industrialization, high population growth and current vulnerability of the climatic condition. Water is becoming scarce as a result of global climate change. To mitigate the problem arising due to global climate change and its drought effect, harvesting rainwater from green roofs, an environmentally-friendly and versatile technology, is becoming one of the best assessment criteria and gaining attention in Malaysia. This paper addresses the sustainability of green roofs and examines the quality of water harvested from green roofs in comparison to rainwater. The factors that affect the quality of such water, taking into account, for example, roofing materials, climatic conditions, the frequency of rainfall frequency and the first flush. A green roof was installed on the Humid Tropic Centre (HTC) is a place of the study on monitoring program for urban Stormwater Management Manual for Malaysia (MSMA), Eco-Hydrological Project in Kualalumpur, and the rainwater was harvested and evaluated on the basis of four parameters i.e., conductivity, dissolved oxygen (DO), pH and temperature. These parameters were found to fall between Class I and Class III of the Interim National Water Quality Standards (INWQS) and the Water Quality Index (WQI). Some preliminary treatment such as disinfection and filtration could likely to improve the value of these parameters to class I. This review paper clearly indicates that there is a need for more research to address other microbiological and chemical quality parameters to ensure that the harvested water is suitable for use potable water for domestic purposes. The change in all physical, chemical and microbiological parameters with respect to storage time will be a major focus of future studies in this field.

Keywords: Green roofs, INWQS, MSMA-SME, rainwater harvesting, water treatment, water quality parameter, WQI

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Authors: Vera Wilden, Benno Hoffmeister, Markus Feldmann

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Glued laminated timber (glulam) is a preferred choice for long span girders, e.g., for gyms or storage halls. While the material provides sufficient strength to resist the bending moments, large spans lead to increased slenderness of such members and to a higher susceptibility to stability issues, in particular to lateral torsional buckling (LTB). Rules for the determination of the ultimate LTB resistance are provided by Eurocode 5. The verifications of the resistance may be performed using the so called equivalent member method or by means of theory 2nd order calculations (direct method), considering equivalent imperfections. Both methods have significant limitations concerning their applicability; the equivalent member method is limited to rather simple cases; the direct method is missing detailed provisions regarding imperfections and requirements for numerical modeling. In this paper, the results of a test series on slender glulam beams in three- and four-point bending are presented. The tests were performed in an innovative, newly developed testing rig, allowing for a very precise definition of loading and boundary conditions. The load was introduced by a hydraulic jack, which follows the lateral deformation of the beam by means of a servo-controller, coupled with the tested member and keeping the load direction vertically. The deformation-controlled tests allowed for the identification of the ultimate limit state (governed by elastic stability) and the corresponding deformations. Prior to the tests, the structural and geometrical imperfections were determined and used later in the numerical models. After the stability tests, the nearly undamaged members were tested again in pure bending until reaching the ultimate moment resistance of the cross-section. These results, accompanied by numerical studies, were compared to resistance values obtained using both methods according to Eurocode 5.

Keywords: experimental tests, glued laminated timber, lateral torsional buckling, numerical simulation

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Authors: Baba Hassane Ahmed Hisseini, Abdelkrim Bennabi, Rabah Hamzaoui, Lamis Makki, Gaetan Blanck

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Most of the clay soils are known as problematic soils due to their water content, which varies greatly over time. It is observed that they are used to be subject to shrinkage and swelling, thus causing a problem of stability on the structures of civil engineering construction work. They are often excavated and placed in a storage area giving rise to the opening of new quarries. This method has become obsolete today because to protect the environment, we are leading to think differently and opening the way to new research for the improvement of the performance of this type of clay soils to reuse them in the construction field. The solidification and stabilization technique is used to improve the properties of poor quality soils to transform them into materials with a suitable performance for a new use in the civil engineering field rather than to excavate them and store them in the discharge area. In our case, the polymerization method is used for bad clay soils classified as high plasticity soil class A4 according to the French standard NF P11-300, where classical treatment methods with cement or lime are not efficient. Our work concerns clay soil treatment study using raw materials as additives for solidification and stabilization. The geopolymers are synthesized by aluminosilicates materials like fly ash, metakaolin, or blast furnace slag and activated by alkaline solution based on sodium hydroxide (NaOH), sodium silicate (Na2SiO3) or a mixture of both of them. In this study, we present the mechanical properties of the soil clay (A4 type) evolution with geopolymerisation methods treatment. Various mix design of aluminosilicates materials and alkaline solutions were carried at different percentages and different curing times of 1, 7, and 28 days. The compressive strength of the untreated clayey soil could be increased from simple to triple. It is observed that the improvement of compressive strength is associated with a geopolymerization mechanism. The highest compressive strength was found with metakaolin at 28 days.

Keywords: treatment and valorization of clay-soil, solidification and stabilization, alkali-activation of co-product, geopolymerization

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Authors: Sthephanie A. Colmenares, Fabio A. Rojas, Pablo A. Arbeláez, Johann F. Osma, Diana Narvaez

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The loss of functional tissue is a ubiquitous and expensive health care problem, with very limited treatment options for these patients. The golden standard for large bone damage is a cadaveric bone as an allograft with stainless steel support; however, this solution only applies to bones with simple morphologies (long bones), has a limited material supply and presents long term problems regarding mechanical strength, integration, differentiation and induction of native bone tissue. Therefore, the fabrication of a scaffold with biological, physical and chemical properties similar to the human bone with a fabrication method for morphology manipulation is the focus of this investigation. Towards this goal, an alginate and coral matrix was created using two production techniques; the coral was chosen because of its chemical composition and the alginate due to its compatibility and mechanical properties. In order to construct the coral alginate scaffold the following methodology was employed; cleaning of the coral, its pulverization, scaffold fabrication and finally the mechanical and biological characterization. The experimental design had: mill method and proportion of alginate and coral, as the two factors, with two and three levels each, using 5 replicates. The coral was cleaned with sodium hypochlorite and hydrogen peroxide in an ultrasonic bath. Then, it was milled with both a horizontal and a ball mill in order to evaluate the morphology of the particles obtained. After this, using a combination of alginate and coral powder and water as a binder, scaffolds of 1cm3 were printed with a SpectrumTM Z510 3D printer. This resulted in solid cubes that were resistant to small compression stress. Then, using a ESQUIM DP-143 silicon mold, constructs used for the mechanical and biological assays were made. An INSTRON 2267® was implemented for the compression tests; the density and porosity were calculated with an analytical balance and the biological tests were performed using cell cultures with VERO fibroblast, and Scanning Electron Microscope (SEM) as visualization tool. The Young’s moduli were dependent of the pulverization method, the proportion of coral and alginate and the interaction between these factors. The maximum value was 5,4MPa for the 50/50 proportion of alginate and horizontally milled coral. The biological assay showed more extracellular matrix in the scaffolds consisting of more alginate and less coral. The density and porosity were proportional to the amount of coral in the powder mix. These results showed that this composite has potential as a biomaterial, but its behavior is elastic with a small Young’s Modulus, which leads to the conclusion that the application may not be for long bones but for tissues similar to cartilage.

Keywords: alginate, biomaterial, bone engineering, coral, Porites asteroids, SEM

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Authors: I. Wlasny, Z. Klusek, A. Wysmolek

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Hexagonal boron nitride is a representative of a widely popular class of two-dimensional Van Der Waals materials. It finds its uses, among others, in construction of complexly layered heterostructures. Hexagonal boron nitride attracts great interest because of its properties characteristic for wide-gap semiconductors as well as an ultra-flat surface.Van Der Waals heterostructures composed of two-dimensional layered materials, such as transition metal dichalcogenides or graphene give hope for miniaturization of various electronic and optoelectronic elements. In our presentation, we will show the results of our investigations of the not previously reported modification of the hexagonal boron nitride layers with focused laser beam. The electrostatic force microscopy (EFM) images reveal that the irradiation leads to changes of the local electric fields for a wide range of laser wavelengths (from 442 to 785 nm). These changes are also accompanied by alterations of crystallographic structure of the material, as reflected by Raman spectra. They exhibit high stability and remain visible after at least five months. This behavior can be explained in terms of photoionization of the defect centers in h-BN which influence non-uniform electrostatic field screening by the photo-excited charge carriers. Analyzed changes influence local defect structure, and thus the interatomic distances within the lattice. These effects can be amplified by the piezoelectric character of hexagonal boron nitride, similar to that found in nitrides (e.g., GaN, AlN). Our results shed new light on the optical properties of the hexagonal boron nitride, in particular, those associated with electron-phonon coupling. Our study also opens new possibilities for h-BN applications in layered heterostructures where electrostatic fields can be used in tailoring of the local properties of the structures for use in micro- and nanoelectronics or field-controlled memory storage. This work is supported by National Science Centre project granted on the basis of the decision number DEC-2015/16/S/ST3/00451.

Keywords: atomic force microscopy, hexagonal boron nitride, optical properties, raman spectroscopy

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Authors: Subesh Panta

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The land is a one of the major boosting factors of production for the agricultural country like Nepal where access to land has been a major source of livelihood of tenants and small farmers. But there is an absence of secure land tenure arrangement which drastically affect the overall production of farmers leading towards food insecurity. Sharecropping is practiced in Nepal especially in tarai region from early period, but there is the gap in the academic study whether the sharecropping has benefitted tenant farmers and make them food sufficient or not. This study attempts to find out the food sufficiency among the tenant households. The research was carried in the three VDCs of Parsa district -Paterwa (Sugauli), Jitpur and Nirchuta. A total of 111 households were determined as the sample size from each of the three VDCs was randomly visited for interview in the study. The size of land rent-in was found to be very small and fragmented. At the same time, the land tenure security was not found to be secured among the tenants. Due to lack of land tenure security, on one hand tenants and small farmers were not found to be motivated to investment in agriculture as they need to share fifty percent of their production with the land owners, and on other hand land owners were also not interested in investing as they have other alternative sources of livelihood rather than agriculture. In conclusion, the study highpoint that the crop production and food sufficiency level of the tenants’ farmers of the Parsa district are decreasing. Many tenants’ farmers are seeking alternative opportunities for livelihood rather than sharecropping due to insecure land tenure, feudalistic practice, lack of storage for agriculture production, lack of proper agro-market. The situation is such that, if no action is taken timely, there may be a situation that we will have to depend on imports for all the food requirements. Thus, the study discloses that the sharecropping could act as catalyst for ensuring food sufficiency for all, if proper land tenure police are promoted to tenants/small farmers with legal titles to their land or promoted with sustainable agriculture methods.

Keywords: agriculture, food sufficiency, land, tenant farmes

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Authors: Yun-Chin Chung, Nileema Divate, Gen-Hung Chen, Pei-Ru Huang, Rupesh Divate

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Many environmental factors, such as glucose concentration, ethanol, temperature, osmotic pressure and pH, decrease the production rate of ethanol using yeast as a starter. Fermentation starters with high tolerance to various stresses are always demanded for brewing industry. Trehalose, a storage carbohydrate in cell wall of yeast, plays an important role in tolerance of environmental stress by preserving integrity of plasma membrane and stabilizing proteins. Furan aldehydes are toxic to yeast and the growth rate of yeast is significantly reduced if furan aldehydes were present in the fermentation medium. In yeast, aldehyde reductase is involved in the detoxification of reactive aldehydes and consequently the growth of yeast is improved. The aims of this study were to construct a genetic recombinant Saccharomyces cerevisiae or Pichia pastoris with furfural and HMF degrading and high ethanol tolerance capacities. Yeast strains were engineered by genetic recombination for overexpression of trehalose-6-phosphate synthase gene (tps1) and aldehyde reductase gene (ari1). TPS1 gene was cloned from S. cerevisiae by reverse transcription-polymerase chain reaction (RT-PCR) and then ligated with pGAPZαC vector. The constructed vector, pGAPZC-tps1, was transformed to recombinant yeasts strain with overexpression of ari1. The transformants with pGAPZC-tps1-ari1 were generated called STA (S. cerevisiae) and PTA (P. pastoris) with overexpression of tps1, ari1. PCR with tps1-specific primers and western blot with his-tag confirmed the gene insertion and protein expression of tps1 in the transformants, respectively. The neutral trehalase gene (nth1) of STA was successfully deleted and the novel strain STAΔN will be used for further study, including the measurement of trehalose concentration and ethanol, furfural tolerance assay.

Keywords: genetic recombinant, yeast, ethanol tolerance, trehalase, aldehyde reductase

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Authors: Tomas Vincze, Michal Micjan, Milan Pavuk, Martin Weis

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In recent years, alternative materials are gaining attention to replace polycrystalline and amorphous silicon, which are a standard for low requirement devices, where silicon is unnecessarily and high cost. For that reason, metal oxides are envisioned as the new materials for these low-requirement applications such as sensors, solar cells, energy storage devices, or field-effect transistors. Their most common way of layer growth is sputtering; however, this is a high-cost fabrication method, and a more industry-suitable alternative is the sol-gel method. In this group of materials, many oxides exhibit a semiconductor-like behavior with sufficiently high mobility to be applied as transistors. The sol-gel method is a cost-effective deposition technique for semiconductor-based devices. Copper oxides, as p-type semiconductors with free charge mobility up to 1 cm2/Vs., are suitable replacements for poly-Si or a-Si:H devices. However, to reach the potential of silicon devices, a fine-tuning of material properties is needed. Here we focus on the optimization of the electrical parameters of copper oxide-based field-effect transistors by modification of precursor solvent (usually 2-methoxy ethanol). However, to achieve solubility and high-quality films, a better solvent is required. Since almost no solvents have both high dielectric constant and high boiling point, an alternative approach was proposed with blend solvents. By mixing isopropyl alcohol (IPA) and 2-methoxy ethanol (2ME) the precursor reached better solubility. The quality of the layers fabricated using mixed solutions was evaluated in accordance with the surface morphology and electrical properties. The IPA:2ME solution mixture reached optimum results for the weight ratio of 1:3. The cupric oxide layers for optimal mixture had the highest crystallinity and highest effective charge mobility.

Keywords: copper oxide, field-effect transistor, semiconductor, sol-gel method

Procedia PDF Downloads 120

Authors: Shang-Hsin Ou, Yang-Chun Lin, Ke-Hao Cheng

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The year 2021 marked a historic drought in Taiwan, posing unprecedented challenges due to record-low rainfall and inadequate reservoir storage. The central region experienced water scarcity, leading to the implementation of "Groundwater Utilization at Construction Sites" for drought-resilient livelihood water supply. This study focuses on the establishment process of temporary groundwater treatment plants at construction sites in Taichung City, serving as a reference for future emergency response and the utilization of construction site groundwater. To identify suitable sites for groundwater reuse projects, site selection operations were carried out based on relevant water quality regulations and assessment principles. Subsequently, the planning and design of temporary water treatment plants were conducted, considering the water quality, quantity, and on-site conditions of groundwater wells associated with construction projects. The study consolidates the major water treatment facilities at each site and addresses encountered challenges during the establishment process. Practical insights gained from operating temporary groundwater treatment plants are presented, including improvements related to stable water quality, water quantity, equipment operation, and hydraulic control. In light of possible future droughts, this study provides an outlook and recommendations to expedite and improve the setup of groundwater treatment plants at construction sites. This includes considering on-site water abstraction, treatment, and distribution conditions. The study's results aim to offer practical guidelines for effectively establishing and managing such treatment plants, while offering experiences and recommendations for other regions facing similar emergencies, water shortages, and drought situations. These endeavors contribute to ensuring sustainable water supply for drought-resilient livelihoods and maintaining societal stability.

Keywords: drought resilience, groundwater treatment, construction site, water supply

Procedia PDF Downloads 70

Authors: Ana C. Sousa, Beatriz C. Santos, Fátima N. Serralha

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The Tagus estuary is heavily affected by industrial and urban activities, making bioremediation studies crucial for environmental preservation. Fuel contamination in the area can arise from various anthropogenic sources, such as oil spills from shipping, fuel storage and transfer operations, and industrial discharges. These pollutants can cause severe harm to the ecosystem and the organisms, including humans, that inhabit it. Nonetheless, there are always natural organisms with the ability to resist these pollutants and transform them into non-toxic or harmless substances, which defines the process of bioremediation. Exploring the microbial communities existing in soil and their capacity to break down hydrocarbons has the potential to enhance the development of more efficient bioremediation approaches. The aim of this investigation was to explore the existence of hydrocarbonoclastic microorganisms in six locations within the Tagus estuary, three on the north bank: Trancão River, Praia Fluvial do Cais das Colinas and Praia de Algés, and three on the south bank: Praia Fluvial de Alcochete, Praia Fluvial de Alburrica, and Praia da Trafaria. In all studied locations, native microorganisms of the genus Pseudomonas were identified. The bioremediation rate of common hydrocarbons like gasoline, hexane, and toluene was assessed using the redox indicator 2,6-dichlorophenolindophenol (DCPIP). Effective hydrocarbon-degrading bacterial strains were identified in all analyzed areas, despite adverse environmental conditions. The highest bioremediation rates were achieved for gasoline (68%) in Alburrica, hexane (65%) in Algés, and toluene (79%) in Algés. Generally, the bacteria demonstrated efficient degradation of hydrocarbons added to the culture medium, with higher rates of aerobic biodegradation of hydrocarbons observed. These findings underscore the necessity for further in situ studies to better comprehend the relationship between native microbial communities and the potential for pollutant degradation in soil.

Keywords: biodegradability rate, hydrocarbonoclastic microorganisms, soil bioremediation, tagus estuary

Procedia PDF Downloads 97

Authors: Vidar Hepsø

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The energy and oil companies on the Norwegian Continental shelf come from a situation where each asset control and manage their energy supply (island mode) and move towards a situation where the assets need to collaborate and coordinate energy use with others due to increased cost and scarcity of electric energy sharing the energy that is provided. Currently, several areas are electrified either with an onshore grid cable or are receiving intermittent energy from offshore wind-parks. While the onshore grid in Norway is well regulated, the offshore grid is still in the making, with several oil and gas electrification projects and offshore wind development just started. The paper will describe the shift in the mindset that comes with operating this new offshore grid. This transition process heralds an increase in collaboration across boundaries and integration of energy management across companies, businesses, technical disciplines, and engagement with stakeholders in the larger society. This transition will be described as a function of the new challenges with increased complexity of the energy mix (wind, oil/gas, hydrogen and others) coupled with increased technical and organization complexity in energy management. Organizational complexity denotes an increasing integration across boundaries, whether these boundaries are company, vendors, professional disciplines, regulatory regimes/bodies, businesses, and across numerous societal stakeholders. New practices must be developed, made legitimate and institutionalized across these boundaries. Only parts of this complexity can be mitigated technically, e.g.: by use of batteries, mixing energy systems and simulation/ forecasting tools. Many challenges must be mitigated with legitimated societal and institutionalized governance practices on many levels. Offshore electrification supports Norway’s 2030 climate targets but is also controversial since it is exploiting the larger society’s energy resources. This means that new systems and practices must also be transparent, not only for the industry and the authorities, but must also be acceptable and just for the larger society. The paper report from ongoing work in Norway, participant observation and interviews in projects and people working with offshore grid development in Norway. One case presented is the development of an offshore floating windfarm connected to two offshore installations and the second case is an offshore grid development initiative providing six installations electric energy via an onshore cable. The development of the offshore grid is analyzed using a capability platform framework, that describes the technical, competence, work process and governance capabilities that are under development in Norway. A capability platform is a ‘stack’ with the following layers: intelligent infrastructure, information and collaboration, knowledge sharing & analytics and finally business operations. The need for better collaboration and energy forecasting tools/capabilities in this stack will be given a special attention in the two use cases that are presented.

Keywords: capability platform, electrification, carbon footprint, control rooms, energy forecsting, operational model

Procedia PDF Downloads 57

Authors: Bolysbek Utelbayev, Tasmagambetova Aigerim, Toktasyn Raila, Markayev Yergali, Myrzakhanov Maxat

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Intensive development of secondary processes of destructive processing of crude oil has led to the occurrence of oil refining factories resources of C2-C4 hydrocarbons. Except for oil gases also contain basically C2-C4 hydrocarbon gases where some of the amounts are burned. All these data has induced interest to the study of producing alkylate from hydrocarbons С2-С4 which being as components of motor fuels. The purpose of this work was studying transformation propane-propene, butane-butene fractions at the presence of the ruthenium-chromic support catalyst whereas the carrier is served pillar - structural montmorillonite containing in native bentonite clay. In this work is considered condition and structure of the bentonite clay from the South-Kazakhstan area of the Republic Kazakhstan. For preparation rhodium support catalyst (0,5-1,0 mass. % Rh) was used chloride of rhodium-RhCl3∙3H2O, as a carrier was used modified bentonite clay. For modifying natural clay to pillar structural form were used polyhydroxy complexes of chromium. To aqueous solution of chloride chromium gradually flowed the solution of sodium hydroxide at gradual hashing up to pH~3-4. The concentration of chloride chromium was paid off proceeding from calculation 5-30 mmole Cr3+ per gram clay. Suspension bentonite (~1,0 mass. %) received by intensive washing it in water during 4 h, pH-water extract of clay makes -8-9. The acidity of environment supervised by means of digital pH meter OP-208/1. In order to prevent coagulation of a solution polyhydroxy complexes of chromium, it was slowly added to a suspension of clay. "Reserve of basicity" Cr3+:/OH-allowing to prevent coagulation chloride of rhodium made 1/3. After endurance processed suspensions of clay during 24 h, a deposit was washed by water and condensed. The sample, after separate from a liquid phase, dried at first at the room temperature, and then at 110°C (2h) with the subsequent rise the temperature up to 180°C (4h). After cooling the firm mass was pounded to a powder, it was shifted infractions with the certain sizes of particles. Fractions of particles modifying clay in the further were impregnated with an aqueous solution with rhodium-RhCl3∙3H2O (0,5-1,0 mаss % Rh ). Obtained pillar structural bentonite approaches heat resistance and its porous structure above the 773K. Pillar structural bentonite was used for preparation 1.0% Ru/Carrier (modifying bentonite) support catalysts where is realised alkylation of C2-C4 hydrocarbons. The process of alkylation is carried out at a partial pressure of hydrogen 0.5-1.0MPa. Outcome 2.2.4 three methyl pentane and 2.2.3 trimethylpentane achieved 40%. At alkylation butane-butene mixture outcome of the isooctane is achieved 60%. In this condition of studying the ethene is not undergoing to alkylation.

Keywords: alkylation, butene, pillar structure, ruthenium catalyst

Procedia PDF Downloads 391

Authors: Renée M. Ripken, Johannes G. E. Gardeniers, Séverine Le Gac

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Controlling the multiphase behavior of aqueous biomass mixtures is essential when working in the biomass conversion industry. Here, the vapor/liquid equilibria (VLE) of ethylene glycol, glycerol, and xylitol were studied for temperatures between 25 and 200 °C and pressures of 1 to 10 bar. These experiments were performed in a microfluidic platform, which exhibits excellent heat transfer properties so that equilibrium is reached fast. Firstly, the saturated vapor pressure as a function of the temperature and the substrate mole fraction of the substrate was calculated using AspenPlus with a Redlich-Kwong-Soave Boston-Mathias (RKS-BM) model. Secondly, we developed a high-pressure and high-temperature microfluidic set-up for experimental validation. Furthermore, we have studied the multiphase flow pattern that occurs after the saturation temperature was achieved. A glass-silicon microfluidic device containing a 0.4 or 0.2 m long meandering channel with a depth of 250 μm and a width of 250 or 500 μm was fabricated using standard microfabrication techniques. This device was placed in a dedicated chip-holder, which includes a ceramic heater on the silicon side. The temperature was controlled and monitored by three K-type thermocouples: two were located between the heater and the silicon substrate, one to set the temperature and one to measure it, and the third one was placed in a 300 μm wide and 450 μm deep groove on the glass side to determine the heat loss over the silicon. An adjustable back pressure regulator and a pressure meter were added to control and evaluate the pressure during the experiment. Aqueous biomass solutions (10 wt%) were pumped at a flow rate of 10 μL/min using a syringe pump, and the temperature was slowly increased until the theoretical saturation temperature for the pre-set pressure was reached. First and surprisingly, a significant difference was observed between our theoretical saturation temperature and the experimental results. The experimental values were 10’s of degrees higher than the calculated ones and, in some cases, saturation could not be achieved. This discrepancy can be explained in different ways. Firstly, the pressure in the microchannel is locally higher due to both the thermal expansion of the liquid and the Laplace pressure that has to be overcome before a gas bubble can be formed. Secondly, superheating effects are likely to be present. Next, once saturation was reached, the flow pattern of the gas/liquid multiphase system was recorded. In our device, the point of nucleation can be controlled by taking advantage of the pressure drop across the channel and the accurate control of the temperature. Specifically, a higher temperature resulted in nucleation further upstream in the channel. As the void fraction increases downstream, the flow regime changes along the channel from bubbly flow to Taylor flow and later to annular flow. All three flow regimes were observed simultaneously. The findings of this study are key for the development and optimization of a microreactor for hydrogen production from biomass.

Keywords: biomass conversion, high pressure and high temperature microfluidics, multiphase, phase diagrams, superheating

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Authors: Thamer Alshuwaili, Yonglin Ren, Bob Du, Manjree Agarwal

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The warehouse beetle, Trogoderma variabile Ballion (Coleoptera: Dermestidae), is a major pest of packaged and processed stored products. Warehouse beetle is the common name which was given by Okumura (1972). This pest has been reported to infest 119 different commodities, and it is distributed throughout the tropical and subtropical parts of the world. Also, it is difficult to control because of the insect's ability to stay without food for long times, and it can survive for years under dry conditions and low-moisture food, and it has also developed resistance to many insecticides. The young larvae of these insects can cause damage to seeds, but older larvae prefer to feed on whole grains. The percentage of damage caused by these insects range between 30-70% in the storage. T. variabile is the species most responsible for causing significant damage in grain stores worldwide. Trogoderma spp. is a huge problem for cereal grains, and there are many countries, such as the USA, Australia, China, Kenya, Uganda and Tanzania who have specific quarantine regulations against possible importation. Also, grain stocks can be almost completely destroyed because of the massive populations the insect may develop. However, the purpose of the current research was to optimize conditions to collect volatile organic compound from Trogoderma variabile at different life stages by using headspace solid phase microextraction (SPME) coupled with gas chromatography-mass spectrometry (GC-MS) and flame ionization detection (FID). Using SPME technique to extract volatile from insects is an efficient, straightforward and nondestructive method. Result of the study shows that 15 insects were optimal number for larvae and adults. Selection of the number of insects depend on the height of the peak area and the number of peaks. Sixteen hours were optimized as the best extraction time for larvae and 8 hours was the optimal number of adults.

Keywords: Trogoderma variabile, warehouse beetle , GC-MS, Solid phase microextraction

Procedia PDF Downloads 115

Authors: Abdulrahman M. Alajlan, Saichao Dang, Qiaoqiang Gan

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Photovoltaic (PV) cells, while pivotal for solar energy harnessing, confront a challenge due to the presence of persistent residual heat. This thermal energy poses significant obstacles to the performance and longevity of PV cells. Mitigating this thermal issue is imperative, particularly in tropical regions where solar abundance coexists with elevated ambient temperatures. In response, a sustainable and economically viable solution has been devised, incorporating water-passive cooling within a Photovoltaic-Thermoelectric (PV-TEG) hybrid system to address PV cell overheating. The implemented system has significantly reduced the operating temperatures of PV cells, achieving a notable reduction of up to 15 °C below the temperature observed in standalone PV systems. In addition, a thermoelectric generator (TEG) integrated into the system significantly enhances power generation, particularly during nighttime operation. The developed hybrid system demonstrates its capability to generate power at a density of 0.5 Wm⁻² during nighttime, which is sufficient to concurrently power multiple light-emitting diodes, demonstrating practical applications for nighttime power generation. Key findings from this research include a consistent temperature reduction exceeding 10 °C for PV cells, translating to a 5% average enhancement in PV output power compared to standalone PV systems. Experimental demonstrations underscore nighttime power generation of 0.5 Wm⁻², with the potential to achieve 0.8 Wm⁻² through simple geometric optimizations. The optimal cooling of PV cells is determined by the volume of water in the heat storage unit, exhibiting an inverse relationship with the optimal performance for nighttime power generation. Furthermore, the TEG output effectively powers a lighting system with up to 5 LEDs during the night. This research not only proposes a practical solution for maximizing solar radiation utilization but also charts a course for future advancements in energy harvesting technologies.

Keywords: photovoltaic-thermoelectric systems, nighttime power generation, PV thermal management, PV cooling

Procedia PDF Downloads 69

Authors: Akbar Khodavirdizadeh, Ali Nemati Babaylou, Hassan Moomivand

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The history of human access to water technique has been one of the factors in the formation of human civilizations in the ancient world. The technique that makes surface water and groundwater accessible to humans on the ground has been a clever technique in human life to reach the water. In this study, while examining the water technique of ancient Iran using the Qanats technique, the water supply system of different regions of the ancient world were also studied and compared. Six groups of the ancient region of ancient Greece (Archaic 480-750 BC and Classical 223-480 BC), Urartu in Tuspa (600-850 BC), Petra (106-168 BC), Ancient Rome (265 BC), and the ancient United States (1450 BC) and ancient Iranian water technologies were studied under water supply systems. Past water technologies in these areas: water transmission systems in primary urban centers, use of water structures in water control, use of bridges in water transfer, construction of waterways for water transfer, storage of rainfall, construction of various types of pottery- ceramic, lead, wood and stone pipes have been used in water transfer, flood control, water reservoirs, dams, channel, wells, and Qanat. The central plateau of Iran is one of the arid and desert regions. Archaeological, geomorphological, and paleontological studies of the central region of the Iranian plateau showed that without the use of Qanats, the possibility of urban civilization in this region was difficult and even impossible. Zarch aqueduct is the most important aqueduct in Yazd region. Qanat of Zarch is a plain Qanat with a gallery length of 80 km; its mother well is 85 m deep and has 2115 well shafts. The main purpose of building the Qanat of Zārch was to access the groundwater source and transfer it to the surface of the ground. Regarding the structure of the aqueduct and the technique of transferring water from the groundwater source to the surface, it has a great impact on being different from other water techniques in the ancient world. The results show that the use of water technologies in ancient is very important to understand the history of humanity in the use of hydraulic techniques.

Keywords: ancient water technologies, groundwaters, qanat, human history, Ancient Iran

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Authors: S. L. J. Tan, N. Billa, C. J. Roberts

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Oral delivery of amphotericin B (AmpB) potentially eliminates constraints and side effects associated with intravenous administration, but remains challenging due to the physicochemical properties of the drug such that it results in meagre bioavailability (0.3%). In an advanced formulation, 1) nanostructured lipid carriers (NLC) were formulated as they can accommodate higher levels of cargoes and restrict drug expulsion and 2) a mucoadhesion feature was incorporated so as to impart sluggish transit of the NLC along the gastrointestinal tract and hence, maximize uptake and improve bioavailability of AmpB. The AmpB-loaded NLC formulation was successfully formulated via high shear homogenisation and ultrasonication. A chitosan coating was adsorbed onto the formed NLC. Physical properties of the formulations; particle size, zeta potential, encapsulation efficiency (%EE), aggregation states and mucoadhesion as well as the effect of the variable pH on the integrity of the formulations were examined. The particle size of the freshly prepared AmpB-loaded NLC was 163.1 ± 0.7 nm, with a negative surface charge and remained essentially stable over 120 days. Adsorption of chitosan caused a significant increase in particle size to 348.0 ± 12 nm with the zeta potential change towards positivity. Interestingly, the chitosan-coated AmpB-loaded NLC (ChiAmpB NLC) showed significant decrease in particle size upon storage, suggesting 'anti-Ostwald' ripening effect. AmpB-loaded NLC formulation showed %EE of 94.3 ± 0.02 % and incorporation of chitosan increased the %EE significantly, to 99.3 ± 0.15 %. This suggests that the addition of chitosan renders stability to the NLC formulation, interacting with the anionic segment of the NLC and preventing the drug leakage. AmpB in both NLC and ChiAmpB NLC showed polyaggregation which is the non-toxic conformation. The mucoadhesiveness of the ChiAmpB NLC formulation was observed in both acidic pH (pH 5.8) and near-neutral pH (pH 6.8) conditions as opposed to AmpB-loaded NLC formulation. Hence, the incorporation of chitosan into the NLC formulation did not only impart mucoadhesive property but also protected against the expulsion of AmpB which makes it well-primed as a potential oral delivery system for AmpB.

Keywords: Amphotericin B, mucoadhesion, nanostructured lipid carriers, oral delivery

Procedia PDF Downloads 151

Authors: Sam Derakhshan Deilami, Iain N. Kings, Lynne E. Macaskie, Brajendra K. Sharma, Anthony V. Bridgwater, Joseph Wood

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This paper reports the application of a bacteria-supported palladium catalyst to the hydrodeoxygenation (HDO) of pyrolysis bio-oil, towards producing an upgraded transport fuel. Biofuels are key to the timely replacement of fossil fuels in order to mitigate the emissions of greenhouse gases and depletion of non-renewable resources. The process is an essential step in the upgrading of bio-oils derived from industrial by-products such as agricultural and forestry wastes, the crude oil from pyrolysis containing a large amount of oxygen that requires to be removed in order to create a fuel resembling fossil-derived hydrocarbons. The bacteria supported catalyst manufacture is a means of utilizing recycled metals and second life bacteria, and the metal can also be easily recovered from the spent catalysts after use. Comparisons are made between bio-Pd, and a conventional activated carbon supported Pd/C catalyst. Bio-oil was produced by fast pyrolysis of beechwood at 500 C at a residence time below 2 seconds, provided by Aston University. 5 wt % BioPd/C was prepared under reducing conditions, exposing cells of E. coli MC4100 to a solution of sodium tetrachloropalladate (Na2PdCl4), followed by rinsing, drying and grinding to form a powder. Pd/C was procured from Sigma-Aldrich. The HDO experiments were carried out in a 100 mL Parr batch autoclave using ~20g bio-crude oil and 0.6 g bio-Pd/C catalyst. Experimental variables investigated for optimization included temperature (160-350C) and reaction times (up to 5 h) at a hydrogen pressure of 100 bar. Most of the experiments resulted in an aqueous phase (~40%) and an organic phase (~50-60%) as well as gas phase (<5%) and coke (<2%). Study of the temperature and time upon the process showed that the degree of deoxygenation increased (from ~20 % up to 60 %) at higher temperatures in the region of 350 C and longer residence times up to 5 h. However minimum viscosity (~0.035 Pa.s) occurred at 250 C and 3 h residence time, indicating that some polymerization of the oil product occurs at the higher temperatures. Bio-Pd showed a similar degree of deoxygenation (~20 %) to Pd/C at lower temperatures of 160 C, but did not rise as steeply with temperature. More coke was formed over bio-Pd/C than Pd/C at temperatures above 250 C, suggesting that bio-Pd/C may be more susceptible to coke formation than Pd/C. Reactions occurring during bio-oil upgrading include catalytic cracking, decarbonylation, decarboxylation, hydrocracking, hydrodeoxygenation and hydrogenation. In conclusion, it was shown that bio-Pd/C displays an acceptable rate of HDO, which increases with residence time and temperature. However some undesirable reactions also occur, leading to a deleterious increase in viscosity at higher temperatures. Comparisons are also drawn with earlier work on the HDO of Chlorella derived bio-oil manufactured from micro-algae via hydrothermal liquefaction. Future work will analyze the kinetics of the reaction and investigate the effect of bi-metallic catalysts.

Keywords: bio-oil, catalyst, palladium, upgrading

Procedia PDF Downloads 163

Authors: Muhammad Afzal, Shahbaz Mushtaq, Duc-Anh-An-Vo, Kathryn Reardon Smith, Thanh Ma

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Climate change has become one of the most challenging environmental issues in the 21st century. Climate change-induced natural disasters, especially floods, are the major factors of livelihood vulnerability, impacting millions of individuals worldwide. Evaluating and mitigating the effects of floods requires an in-depth understanding of the relationship between vulnerability and livelihood capital assets. Using an integrated approach, sustainable livelihood framework, and system thinking approach, the study developed a conceptual model of a generalized livelihood system in District Rajanpur, Pakistan. The model visualizes the livelihood vulnerability system as a whole and identifies the key feedback loops likely to influence the livelihood vulnerability. The study suggests that such conceptual models provide effective communication and understanding tools to stakeholders and decision-makers to anticipate the problem and design appropriate policies. It can also serve as an evaluation technique for rural livelihood policy and identify key systematic interventions. The key finding of the study reveals that household income, health, and education are the major factors behind the livelihood vulnerability of the rural poor of District Rajanpur. The Pakistani government tried to reduce the livelihood vulnerability of the region through different income, health, and education programs, but still, many changes are required to make these programs more effective especially during the flood times. The government provided only cash to vulnerable and marginalized families through income support programs, but this study suggests that along with the cash, the government must provide seed storage facilities and access to crop insurance to the farmers. Similarly, the government should establish basic health units in villages and frequent visits of medical mobile vans should be arranged with advanced medical lab facilities during and after the flood.

Keywords: livelihood vulnerability, rural communities, flood, sustainable livelihood framework, system dynamics, Pakistan

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Authors: Antonio J. Melendez-Martinez

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Beyond their role as natural colorants, some carotenoids are provitamins A and may be involved in health-promoting biological actions and contribute to reducing the risk of developing non-communicable diseases, including several types of cancer, cardiovascular disease, eye conditions, skin disorders or metabolic disorders. Given the versatility of carotenoids, the COST-funded European network to advance carotenoid research and applications in agro-food and health (EUROCAROTEN) is aimed at promoting health through the diet and increasing well-being by means. Stakeholders from 38 countries participate in this network, and one of its main objectives is to promote research on little-studied carotenoids. In this contribution, recent advances of our research group and collaborators in the study of two such understudied carotenoids, namely phytoene and phytofluene, the colorless carotenoids, are outlined. The study of these carotenoids is important as they have been largely neglected despite they are present in our diets, fluids, and tissues, and evidence is accumulating that they may be involved in health-promoting actions. More specifically, studies on their levels in diverse tomato and orange varieties were carried out as well as on their potential bioavailability from different dietary sources. Furthermore, the potential effect of these carotenoids on an animal model subjected to oxidative stress was evaluated. The tomatoes were grown in research greenhouses, and some of them were subjected to regulated deficit irrigation, a sustainable agronomic practice. The citrus samples were obtained from an experimental field. The levels of carotenoids were assessed using HPLC according to routine methodologies followed in our lab. Regarding the potential bioavailability (bioaccessibility) studies, different products containing colorless carotenoids, like fruits, juices, were subjected to simulated in vitro digestions, and their incorporation into mixed micelles was assessed. The effect of the carotenoids on oxidative stress was evaluated on the Caenorhabditis elegans model. For that purpose, the worms were subjected to oxidative stress by means of a hydrogen peroxide challenge. In relation to the presence of colorless carotenoids in tomatoes and orange varieties, it was observed that they are widespread in such products and that there are mutants with very high quantities of them, for instance, the Cara Cara or Pinalate mutant oranges. The studies on their bioaccessibility revealed that, in general, phytoene and phytofluene are more bioaccessible than other common dietary carotenoids, probably due to their distinctive chemical structure. About the in vivo antioxidant capacity of phytoene and phytofluene, it was observed that they both exerted antioxidant effects at certain doses. In conclusion, evidence on the importance of phytoene and phytofluene as dietary easily bioavailable and antioxidant carotenoids has been obtained in recent studies from our group, which can be important shortly to innovate in health-promotion through the development of functional foods and related products.

Keywords: carotenoids, health, functional foods, nutrition, phytoene, phytofluene

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Authors: Bukunola K. Oguntade, Gareth M. Watkins

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The synthesis and characterization of metal-organic frameworks (MOFs) is an area of coordination chemistry which has grown rapidly in recent years. Worldwide there has been growing concerns about future energy supplies, and its environmental impacts. A good number of MOFs have been tested for the adsorption of small molecules in the vapour phase. An important issue for potential applications of MOFs for gas adsorption and storage materials is the stability of their structure upon sorption. Therefore, study on the thermal stability of MOFs upon adsorption is important. The incorporation of two or more transition metals in a coordination polymer is a current challenge for designed synthesis. This work focused on the synthesis, characterization and small molecule adsorption properties of three microporous (one zinc monometal and two bimetallics) complexes involving Cu(II), Zn(II) and 1,2,4,5-benzenetetracarboxylic acid using the ambient precipitation and solvothermal method. The complexes were characterized by elemental analysis, Infrared spectroscopy, Scanning Electron microscopy, Thermogravimetry analysis and X-ray Powder diffraction. The N2-adsorption Isotherm showed the complexes to be of TYPE III in reference to IUPAC classification, with very small pores only capable for small molecule sorption. All the synthesized compounds were observed to contain water as guest. Investigations of their inclusion properties for small molecules in the vapour phase showed water and methanol as the only possible inclusion candidates with 10.25H2O in the monometal complex [Zn4(H2B4C)2.5(OH)3(H2O)]·10H2O but not reusable after a complete structural collapse. The ambient precipitation bimetallic; [(CuZnB4C(H2O)2]·5H2O, was found to be reusable and recoverable from structure collapse after adsorption of 5.75H2O. In addition, Solvo-[CuZnB4C(H2O)2.5]·2H2O obtained from solvothermal method show two cycles of rehydration with 1.75H2O and 0.75MeOH inclusion while structure remains unaltered upon dehydration and adsorption.

Keywords: adsorption, characterization, copper, metal -organic frameworks, zinc

Procedia PDF Downloads 121