Search results for: intermediate temperature solid oxide fuel cells

Authors: O. W. Lawal, L. O. Ahmed, Y. K. Ali

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The unsteady MHD Poiseuille flow of a third grade fluid between two parallel horizontal nonconducting porous plates is studied with heat transfer. The two plates are fixed but maintained at different constant temperature with the Joule and viscous dissipation taken into consideration. The fluid motion is produced by a sudden uniform exponential decaying pressure gradient and external uniform magnetic field that is perpendicular to the plates. The momentum and energy equations governing the flow are solved numerically using Maple program. The effects of magnetic field and third grade fluid parameters on velocity and temperature profile are examined through several graphs.

Keywords: exponential decaying pressure gradient, MHD flow, Poiseuille flow, third grade fluid

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Authors: Y. Chabouni, F. Amireche

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Densities of glycerol + 1-butanol or 2-butanol mixtures were measured over the temperature range 293.15 to 303.15 K at atmospheric pressure, over the entire composition range, with a vibrating tube densimeter. Excess molar volumes, apparent and partial molar volumes of glycerol and butanol, thermal isobaric expansivities of the mixture and partial molar expansivities of the components were calculated. The excess molar volumes of the mixtures are negative at all temperatures, and deviations from ideality increase with increasing temperature. Excess molar volumes were fitted to the Redlich–Kister equation. Partial molar volumes of glycerol decrease with increasing butanol concentration.

Keywords: 1-Butanol, 2-Butanol, density, excess molar volume, glycerol, partial molar property, thermal isobaric expansivities

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Authors: Agman Gupta, Rajashekar Badam, Noriyoshi Matsumi

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Introduction: Recently, silicon has been recognized as one of the potential alternatives as anode active material in Li-ion batteries (LIBs) to replace the conventionally used graphite anodes. Silicon is abundantly present in the nature, it can alloy with lithium metal, and has a higher theoretical capacity (~4200 mAhg-1) that is approximately 10 times higher than graphite. However, because of a large volume expansion (~400%) upon repeated de-/alloying, the pulverization of Si particles causes the exfoliation of electrode laminate leading to the loss of electrical contact and adversely affecting the formation of solid-electrolyte interface (SEI).1 Functional polymers as binders have emerged as a competitive strategy to mitigate these drawbacks and failure mechanism of silicon anodes.1 A variety of aqueous/non-aqueous polymer binders like sodium carboxy-methyl cellulose (CMC-Na), styrene butadiene rubber (SBR), poly(acrylic acid), and other variants like mussel inspired binders have been investigated to overcome these drawbacks.1 However, there are only a few reports that mention the attempt of addressing all the drawbacks associated with silicon anodes effectively using a single novel functional polymer system as a binder. In this regard, here, we report a novel highly robust n-type bisiminoacenaphthenequinone (BIAN)-paraphenylene-based crosslinked polymer as a binder for Si anodes in lithium-ion batteries (Fig. 1). On its application, crosslinked-BIAN binder was evaluated to provide mechanical robustness to the large volume expansion of Si particles, maintain electrical conductivity within the electrode laminate, and facilitate in the formation of a thin SEI by restricting the extent of electrolyte decomposition on the surface of anode. The fabricated anodic half-cells were evaluated electrochemically for their rate capability, cyclability, and discharge capacity. Experimental: The polymerized BIAN (P-BIAN) copolymer was synthesized as per the procedure reported by our group.2 The synthesis of crosslinked P-BIAN: a solution of P-BIAN copolymer (1.497 g, 10 mmol) in N-methylpyrrolidone (NMP) (150 ml) was set-up to stir under reflux in nitrogen atmosphere. To this, 1,6-dibromohexane (5 mmol, 0.77 ml) was added dropwise. The resultant reaction mixture was stirred and refluxed at 150 °C for 24 hours followed by refrigeration for 3 hours at 5 °C. The product was obtained by evaporating the NMP solvent under reduced pressure and drying under vacuum at 120 °C for 12 hours. The obtained product was a black colored sticky compound. It was characterized by 1H-NMR, XPS, and FT-IR techniques. Results and Discussion: The N 1s XPS spectrum of the crosslinked BIAN polymer showed two characteristic peaks corresponding to the sp2 hybridized nitrogen (-C=N-) at 399.6 eV of the diimine backbone in the BP and quaternary nitrogen at 400.7 eV corresponding to the crosslinking of BP via dibromohexane. The DFT evaluation of the crosslinked BIAN binder showed that it has a low lying lowest unoccupied molecular orbital (LUMO) that enables it to get doped in the reducing environment and influence the formation of a thin (SEI). Therefore, due to the mechanically robust crosslinked matrices as well as its influence on the formation of a thin SEI, the crosslinked BIAN binder stabilized the Si anode-based half-cell for over 1000 cycles with a reversible capacity of ~2500 mAhg-1 and ~99% capacity retention as shown in Fig. 2. The dynamic electrochemical impedance spectroscopy (DEIS) characterization of crosslinked BIAN-based anodic half-cell confirmed that the SEI formed was thin in comparison with the conventional binder-based anodes. Acknowledgement: We are thankful to the financial support provided by JST-Mirai Program, Grant Number: JP18077239

Keywords: self-healing binder, n-type binder, thin solid-electrolyte interphase (SEI), high-capacity silicon anodes, low-LUMO

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Authors: Luz Stella Cadavid-Rodriguez, Viviana E. Castro-Lopez

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Fish waste (FW) has a high content of potentially biodegradable components, so it is amenable to be digested anaerobically. In this line, anaerobic digestion (AD) of FW has been studied for biogas production. Nevertheless, intermediate products such as volatile fatty acids (VFA), generated during the acidogenic stage, have been scarce investigated, even though they have a high potential as a renewable source of carbon. In the literature, there are few studies about the Inoculum-Substrate (I/S) ratio on acidogenesis. On the other hand, it is well known that pH is a critical factor in the production of VFA. The optimum pH for the production of VFA seems to change depending on the substrate and can vary in a range between 5.25 and 11. Nonetheless, the literature about VFA production from protein-rich waste, such as FW, is scarce. In this context, it is necessary to deepen on the determination of the optimal operating conditions of acidogenic fermentation for VFA production from protein-rich waste. Therefore, the aim of this research was to optimize the volatile fatty acid production from artisanal fishing waste, studying the effect of pH and the I/S ratio on the acidogenic process. For this research, the inoculum used was a methanogenic sludge (MS) obtained from a UASB reactor treating wastewater of a slaughterhouse plant, and the FW was collected in the port of Tumaco (Colombia) from the local artisanal fishers. The acidogenic fermentation experiments were conducted in batch mode, in 500 mL glass bottles as anaerobic reactors, equipped with rubber stoppers provided with a valve to release biogas. The effective volume used was 300 mL. The experiments were carried out for 15 days at a mesophilic temperature of 37± 2 °C and constant agitation of 200 rpm. The effect of 3 pH levels: 5, 7, 9, coupled with five I/S ratios, corresponding to 0.20, 0.15, 0.10, 0.05, 0.00 was evaluated taking as a response variable the production of VFA. A complete randomized block design was selected for the experiments in a 5x3 factorial arrangement, with two repetitions per treatment. At the beginning and during the process, pH in the experimental reactors was adjusted to the corresponding values of 5, 7, and 9 using 1M NaOH or 1M H2SO4, as was appropriated. In addition, once the optimum I/S ratio was determined, the process was evaluated at this condition without pH control. The results indicated that pH is the main factor in the production of VFA, obtaining the highest concentration with neutral pH. By reducing the I/S ratio, as low as 0.05, it was possible to maximize VFA production. Thus, the optimum conditions found were natural pH (6.6-7.7) and I/S ratio of 0.05, with which it was possible to reach a maximum total VFA concentration of 70.3 g Ac/L, whose major components were acetic acid (35%) and butyric acid (32%). The findings showed that the acidogenic fermentation of FW is an efficient way of producing VFA and that the operating conditions can be simple and economical.

Keywords: acidogenesis, artisanal fishing waste, inoculum to substrate ratio, volatile fatty acids

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Authors: Sabrina Sebbane, Alina Elena Parvu

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Introduction: Santolina rosmarinifolia is a plant of the Santolina genus, a family made of medicinal plants widely used. Some of the Santolina species have been proven to have potent anti-inflammatory and anti-oxidant effects. However, no in vivo study has been made to demonstrate this in Santolina rosmarinifolia. The aim of our study is to experimentally evaluate the potential anti-inflammatory and anti-oxidant effects of Santolina rosmarinifolia plant extracts on acute inflammation in rats. These effects are defined by measuring the modifications on nitric oxide, reactive oxygen species and anti-oxidant response in serum. Materials and Methods: Rats were divided into 5 groups (n=6). Three groups were given Santolina rosmarinifolia extract by gavage in different concentrations(100%, 50%, 25%) for a week. Inflammation was induced by i.m injection of turpentine oil on the 8th day. One group was only given turpentine oil and the fifth group acted as control and was given only saline solution. Blood was collected and serum separated. Global tests were used to measure the oxidative stress, total oxidative status (TOS), total antioxidant reactivity (TAR) and the modified method of Griess assay to measure NO synthesis. Malondilaldehyde (MDA) and thiols levels were also assessed. Results: Santolina rosmarinifolia did not significantly change the TOS levels (p > 0.05). Santolina rosmarinifolia 25% and 50% decreased significantly the TAR levels (p < 0.001). Santolina 100% didn't have a significant effect on TAR (p > 0.05). All concentrations of Santolina rosmarinifolia increased the oxidative stress index (OSI) significantly(p < 0.05). Santolina rosmarinifolia 100% significantly decreased NO synthesis (p value < 0.05). In the diluted Santolina groups, no significant effect on NO synthesis was observed. In the groups treated with Santolina 100% and Santolina rosmarinifolia 50%, thiols concentration were significantly higher compared to the inflammation group (p < 0.02). A higher stimulatory effect was found in the Santolina 25% group (p value < 0.05). MDA levels were not significantly modified by the administration of Santolina rosmarinifolia (p > 0.05). Conclusion: All three solutions of Santolina rosmarinifolia had no important effect on oxidant production. However, Santolina rosmarinifolia solutions had a positive effect by increasing the thiols concentration in the serum of the models. The sum of all the effects produced by the administration of Santolina did not show a significant decrease of nitro-oxidative stress. Further experiments including smaller concentrations of Santolina rosmarinifolia will be made. Santolina rosmarinifolia should also be tested as a curative treatment.

Keywords: inflammation, MDA, nitric oxide, santolina rosmarinifolia, thiols, TAR, TOS

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Authors: Dehni Abdellatif, Lounis Mourad

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The new approach of applied spatial geostatistics in materials sciences, agriculture accuracy, agricultural statistics, permitted an apprehension of managing and monitoring the water and groundwater qualities in a relationship with salt-affected soil. The anterior experiences concerning data acquisition, spatial-preparation studies on optical and multispectral data has facilitated the integration of correction models of electrical conductivity related with soils temperature (horizons of soils). For tomography apprehension, this physical parameter has been extracted from calibration of the thermal band (LANDSAT ETM+6) with a radiometric correction. Our study area is Oran region (Northern West of Algeria). Different spectral indices are determined such as salinity and sodicity index, the Combined Spectral Reflectance Index (CSRI), Normalized Difference Vegetation Index (NDVI), emissivity, Albedo, and Sodium Adsorption Ratio (SAR). The approach of geostatistical modeling of electrical conductivity (salinity), appears to be a useful decision support system for estimating corrected electrical resistivity related to the temperature of surface soils, according to the conversion models by substitution, the reference temperature at 25°C (where hydrochemical data are collected with this constraint). The Brightness temperatures extracted from satellite reflectance (LANDSAT ETM+) are used in consistency models to estimate electrical resistivity. The confusions that arise from the effects of salt stress and water stress removed followed by seasonal application of the geostatistical analysis in Geographic Information System (GIS) techniques investigation and monitoring the variation of the electrical conductivity in the alluvial aquifer of Es-Sénia for the salt-affected soil.

Keywords: geostatistical modelling, landsat, brightness temperature, conductivity

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Authors: Butchi Kameswara Rao Chittem, Rooban Kumar

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Cement concrete is a complex mixture of different materials. Concrete is believed to have a good fire resistance. Behaviour of concrete depends on its mix proportions and its constituent materials when it is subjected to elevated temperatures. Loss in compressive strength, loss in weight or mass, change in colour and spall of concrete are reported in literature as effects of elevated temperature on concrete. In this paper results are reported on the behaviour of normal strength concrete and high strength concrete subjected to temperatures 200°C, 400°C, 600°C, and 800°C and different cooling regimes viz. air cooling, water quenching. Rebound hammer test was also conducted to study the changes in surface hardness of concrete specimens subjected to elevated temperatures.

Keywords: normal strength concrete, high-strength concrete, temperature, NDT

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Authors: K. Daoudi, Z. Othmen, S. El Helali, M.Oueslati, M. Oumezzine

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La0.7Sr0.3CoO3 thin films have been epitaxially grown on LaAlO3 and SrTiO3 (001) single-crystal substrates by metal organic deposition process. The structural and micro structural properties of the obtained films have been investigated by means of high resolution X-ray diffraction, Raman spectroscopy and transmission microscopy observations on cross-sections techniques. We noted a close dependence of the crystallinity on the used substrate and the film thickness. By increasing the annealing temperature to 1000ºC and the film thickness to 100 nm, the electrical resistivity was decreased by several orders of magnitude. The film resistivity reaches approximately 3~4 x10-4 Ω.cm in a wide interval of temperature 77-320 K, making this material a promising candidate for a variety of applications.

Keywords: cobaltite, thin films, epitaxial growth, MOD, TEM

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Authors: Nada A. El-Shahaw, Anas A.Salem, M. Kobeisy, Hoda M. Shabaan

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Reactive oxygen species (ROS) is collective term both oxygen radical, such superoxide (O₂•), hydroxyl(OH•), peroxyl (RO₂), and hydroperoxyl (HO₂•), and certain non-radical oxidizing agents, such as hydrogen peroxide (H₂O₂), hypochlorous acid (HOCL), and ozone (O₃), that can be convert easily to radical. The importance of antioxidants is shown here punicalagin. Punicalagin is preventing the harmful effect of (ROS) in all cells, specially gonadal cells. So, the aim of study was to investigate effects of punicalagin (PL) on maternal live body weight (MLBW), number of services/conception (NS), conception rate (CR), gestation length (GL), kindling rate (KR), total litter size (TLS), live litter size (LLS), kit weight (KW), progesterone (P4) and estradiol-17 (E2) concentrations at 1st and 2nd pregnancy of young does. A total of 28 healthy virgin does (6 months old) were divided into 2 equal groups. Group I, each doe, was injected IM with 100 ug PL twice/week pre-mating and one time 3 days post-mating. Group II, each doe was injected IM with sterilized water (control). Blood samples were taken at pre-mating, mating, post-mating, throughout pregnancy, and immediately post-kindling for assaying P4 and E2. All does were naturally mated with fertile bucks. Results revealed that PL displayed their significant impacts on MLBW, NS/conception, CR, GL, KR, TLS, LLS, KWs (birth and weaning), P4 and E2 concentrations either at 1ˢᵗ/2ⁿᵈ pregnancy or both of them. Conclusively, PL improved pregnancy outcomes of young do particularly at 2ⁿᵈ pregnancy and could be recommended in rabbit's farms.

Keywords: punicalagin, pregnancy, estradiol-17β, progesterone, does

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Authors: Ayuko Itsuki, Sachiyo Aburatani

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The seasonal (January, April, July and October) and monthly soil respiration rate and the monthly litter fall amounts were examined in the laurel-leaved (B_B-1) and Cryptomeria japonica (B_B-2 and PW) forests in the Kasugayama Hill Primeval Forest (Nara, Japan). The change of the seasonal soil respiration rate corresponded to that of the soil temperature. The soil respiration rate was higher in October when fresh organic matter was supplied in the forest floor than in April in spite of the same temperature. The seasonal soil respiration rate of B_B-1 was higher than that of B_B-2, which corresponded to more numbers of bacteria and fungi counted by the dilution plate method and by the direct count method by microscopy in B_B-1 than that of B_B-2. The seasonal soil respiration rate of B_B-2 was higher than that of PW, which corresponded to more microbial biomass by the direct count method by microscopy in B_B-2 than that of PW. The correlation coefficient with the seasonal soil respiration and the soil temperature was higher than that of the monthly soil respiration. The soil respiration carbon was more than the litter fall carbon. It was suggested that the soil respiration included in the carbon dioxide which was emitted by the plant root and soil animal, or that the litter fall supplied to the forest floor included in animal and plant litter.

Keywords: field soil respiration rate, forest soil, litter fall, mineralization rate

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Authors: S. K. Jain, M. K. Mishra

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Oblique propagation of ion-acoustic solitons in magnetized electron-positron-ion (EPI) plasma with warm adiabatic ions and isothermal electrons has been studied. Korteweg-de Vries (KdV) equation using reductive perturbation method has been derived for the system, which admits an obliquely propagating soliton solution. It is found that for the selected set of parameter values, the system supports only compressive solitons. Investigations reveal that an increase in positron concentration diminishes the amplitude as well as the width of the soliton. It is also found that the temperature ratio of electron to positron (γ) affects the amplitude of the solitary wave. An external magnetic field do not affect the amplitude of ion-acoustic solitons, but obliqueness angle (θ), the angle between wave vector and magnetic field affects the amplitude. The amplitude of the ion-acoustic solitons increases with increase in angle of obliqueness. Magnetization and obliqueness drastically affect the width of the soliton. An increase in ionic temperature decreases the amplitude and width. For the fixed set of parameters, profiles have been drawn to study the combined effect with variation of two parameters on the characteristics of the ion-acoustic solitons (i.e., amplitude and width). The result may be applicable to plasma in the laboratory as well as in the magnetospheric region of the earth.

Keywords: ion-acoustic solitons, Korteweg-de Vries (KdV) equation, magnetized electron-positron-ion (EPI) plasma, reductive perturbation method

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Authors: Chaiyakrit Raoupatham, Ram Hari Dhakal, Chalermchai Wanichlamlert

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This paper is aimed to introduce the solution of concrete slump recovery using chemical admixture type-F (superplasticizer, naphthalene base) to the practice, in order to solve unusable concrete problem due to concrete loss its slump, especially for those tropical countries that have faster slump loss rate. In the other hand, randomly adding superplasticizer into concrete can cause concrete to segregate. Therefore, this paper also develops the estimation model used to calculate amount of second dose of superplasticizer need for concrete slump recovery. Fresh properties of ordinary Portland cement concrete with volumetric ratio of paste to void between aggregate (paste content) of 1.1-1.3 with water-cement ratio zone of 0.30 to 0.67 and initial superplasticizer (naphthalene base) of 0.25%- 1.6% were tested for initial slump and slump loss for every 30 minutes for one and half hour by slump cone test. Those concretes with slump loss range from 10% to 90% were re-dosed and successfully recovered back to its initial slump. Slump after re-dosed was tested by slump cone test. From the result, it has been concluded that, slump loss was slower for those mix with high initial dose of superplasticizer due to addition of superplasticizer will disturb cement hydration. The required second dose of superplasticizer was affected by two major parameter, which were water-cement ratio and paste content, where lower water-cement ratio and paste content cause an increase in require second dose of superplasticizer. The amount of second dose of superplasticizer is higher as the solid content within the system is increase, solid can be either from cement particles or aggregate. The data was analyzed to form an equation use to estimate the amount of second dosage requirement of superplasticizer to recovery slump to its original.

Keywords: estimation model, second superplasticizer dosage, slump loss, slump recovery

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Authors: Nursac Akyol, Merve S. Turan, Mustafa Ozcelik, Erdogan Kucukoner, Erkan Karacabey

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Traditional raisin production is a long time drying process under sunlight. During this procedure, grapes are open to some environmental effects besides the adverse effects of the long drying period. Thus, there is a need to develop an alternative method being applicable instead of traditional one. To this extent, a combination of a potential pretreatment (carbonic maceration, CM) with convectional oven drying was examined. CM application was used in raisin production (grape drying) as a pretreatment process before oven drying. Pressure, temperature and time were examined as application parameters of CM. In conventional oven drying, the temperature is a process variable. The aim is to find out how CM and convectional drying processes affect the drying characteristics of grapes as well as their physical and chemical properties. For this purpose, the response surface method was used to determine both the effects of the variables and the optimum pretreatment and drying conditions. The optimum conditions of CM for raisin production were 0.3 MPa of pressure value, 4°C of application temperature and 8 hours of application time. The optimized drying temperature was 77°C. The results showed that the application of CM before the drying process improved the drying characteristics. Drying took only 389 minutes for grapes pretreated by CM under optimum conditions and 495 minutes for the control group dried only by the conventional drying process. According to these results, a decrease of 21% was achieved in the time requirement for raisin production. Also, it was observed that the samples dried under optimum conditions had similar physical properties as those the control group had. It was seen that raisin, which was dried under optimum conditions were in better condition in terms of some of the bioactive contents compared to control groups. In light of all results, it is seen that CM has an important potential in the industrial drying of grape samples. The current study was financially supported by TUBITAK, Turkey (Project no: 116R038).

Keywords: drying time, pretreatment, response surface methodlogy, total phenolic

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Authors: Chane-Yu Lai, Xiang-Yu Huang

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This study conducted an assessment of sampling result by using the new development rotation filtration device (RFD) filled with porous media filters integrating the method of cyclone centrifugal spins. The testing system established for the experiment used corn oil and potassium sodium tartrate tetrahydrate (PST) as challenge aerosols and were produced by using an Ultrasonic Atomizing Nozzle, a Syringe Pump, and a Collison nebulizer. The collection efficiency of RFD for oil aerosol was assessed by using an Aerodynamic Particle Sizer (APS) and a Fidas® Frog. The results of RFD for the liquid particles condition indicated the cutoff size was 1.65 µm and 1.02 µm for rotation of 0 rpm and 9000 rpm, respectively, under an 80 PPI (pores per inch）foam with a thickness of 80 mm, and sampling velocity of 13.5 cm/s. As the experiment increased the foam thickness of RFD, the cutoff size reduced from 1.62 µm to 1.02 µm. However, when increased the foam porosity of RFD, the cutoff size reduced from 1.26 µm to 0.96 µm. Moreover, as increased the sampling velocity of RFD, the cutoff size reduced from 1.02 µm to 0.76 µm. These discrepancies of above cutoff sizes of RFD all had statistical significance (P < 0.05). The cutoff size of RFD for three experimental conditions of generated liquid oil particles, solid PST particles or both liquid oil and solid PST particles was 1.03 µm, 1.02 µm, or 0.99 µm, respectively, under a 80 PPI foam with thickness of 80 mm, rotation of 9000 rpm, and sampling velocity of 13.5 cm/s. In addition, under the best condition of the experiment, two hours of sampling loading, the RFD had better collection efficiency for particle diameter greater than 0.45 µm, under a 94 PPI nickel mesh with a thickness of 68 mm, rotation of 9000 rpm, and sampling velocity of 108.3 cm/s. The experiment concluded that increased the thickness of porous media, face velocity, and porosity of porous media of RFD could increase the collection efficiency of porous media for sampling oil particles. Moreover, increased the rotation speed of RFD also increased the collection efficiency for sampling oil particles. Further investigation is required for those above operation parameters for RFD in this study in the future.

Keywords: oil aerosol, porous media filter, rotation, filtration

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Authors: Ashna Babu, Deepshikha Jaiswal Nagar

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Cuprate high-temperature superconductors (HTSCs) have been immensely studied during the past few decades because of their structure which is described as a superlattice of superconducting CuO₂ layers. In particular, YBa₂Cu₃O₆₊δ (YBCO), with its critical temperature of 93 K, has received the most attention due to its well-defined metal stoichiometry and variable oxygen content that determines the carrier doping level. Substitution of metal ions at the Cu site is known to increase the critical current density without destroying superconductivity in YBCO. The construction of vortex phase diagrams is very important for such doped YBCO materials both from a fundamental perspective as well as from a technological perspective. By measuring field-dependent magnetization on annealed single crystals of Al-doped YBCO, YBa₂Cu₃₋ₓAlₓO₆₊δ (Al-YBCO), we were able to observe a second magnetization peak anomaly (SMP) in a very large part of the phase diagram. We were also able to observe the SMP anomaly in temperature-dependent magnetization measurements, the first observation to our knowledge. Critical current densities were calculated using Bean’s critical state model, flux jumps associated with symmetry reorientation of vortex lattice were studied, the oxygen cluster distribution was also analysed, and by incorporating all observations, we made a vortex phase diagram for oxygenated Al-YBCO single crystal.

Keywords: oxygen deficient clusters, second magnetization peak anomaly, flux jumps, vortex phase diagram

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Authors: Isalira Peroba Ramos, Cherley Borba Vieira de Andrade, Grazielle Suhett, Camila Salata, Paulo Cesar Canary, Guilherme Visconde Brasil, Antonio Carlos Campos de Carvalho, Regina Coeli dos Santos Goldenberg

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Background: The therapeutic options for patients with cancer now include increasingly complex combinations of medications, radiation therapy (RT), and surgical intervention. Many of these treatments have important potential adverse cardiac effects and are likely to have significant effects on patient outcomes. Cell therapy appears to be promising for the treatment of chronic and degenerative diseases, including cardiomyopathy induced by RT, as the current therapeutic options are insufficient. Aims: To evaluate the potential of bone marrow mesenchymal cells (BMMCs) in radioinduced cardiac damage Methods: Female Wistar rats, 3 months old (Ethics Committee 054/14), were divided into 2 groups, non-treated irradiated group (IR n=15) and irradiated and BMMC treated (IRT n=10). Echocardiography was performed to evaluate heart function. After euthanasia, 3 months post treatment; the left ventricle was removed and prepared for RT-qPCR (VEGF and Pro Collagen I) and histological (picrosirius) analysis. Results: In both groups, 45 days after irradiation, ejection fraction (EF) was in the normal range for these animals (> 70%). However, the BMMC treated group had EF (83.1%±2.6) while the non-treated IR group showed a significant reduction (76.1%±2.6) in relation to the treated group. In addition, we observed an increase in VEGF gene expression and a decrease in Pro Collagen I in IRT when compared to IR group. We also observed by histology that the collagen deposition was reduced in IRT (10.26%±0.83) when compared to IR group (25.29%±0.96). Conclusions: Treatment with BMMCs was able to prevent ejection fraction reduction and collagen deposition in irradiated animals. The increase of VEGF and the decrease of pro collagen I gene expression might explain, at least in part, the cell therapy benefits. All authors disclose no financial or personal relationships with individuals or organizations that could be perceived to bias their work. Sources of funding: FAPERJ, CAPES, CNPq, MCT.

Keywords: mesenchymal cells, radioation, cardiotoxicity, bone marrow

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Authors: J. P. Gorninski, J. M. L. Reis

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This present work was aimed to develop polymeric mortars having as binder two polyester resins namely isophtalic and orthophtalic polyester. The inorganic phase was composed by medium-size river sand and fly ash fíller, a by-product of the burning of coal in power plants. The compositions in this study are high performance mortars and were assessed by mechanical properties, through compressive strength and flexural strength, by durability strength when exposed to the cyclical variation of temperature from -400C to +300C and by the chemical aggression test. The composites displayed good performance when exposed to cyclical temperature variations and chemical solutions. The mechanical strength values reached the 100 MPa, the flexural strength yielded values of about twenty percent of mechanical strength.

Keywords: polymer mortar, mechanical strength, cyclical temperatures, chemical strength, sustainability

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Authors: Jayanwita Sarkar, Usha Chakraborty, Bishwanath Chakraborty

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Plants are constantly interacting with various abiotic and biotic stresses. In changing climate scenario plants are continuously modifying physiological processes to adapt to changing environmental conditions which profoundly affect plant-pathogen interactions. Spot blotch in wheat is a fast-rising disease in the warmer plains of South Asia where the rise in minimum average temperature over most of the year already affecting wheat production. Hence, the study was undertaken to explore the role of elevated temperature in spot blotch disease development and modulation of antioxidative responses by plant growth promoting rhizobacteria (PGPR) for biocontrol of spot blotch at high temperature. Elevated temperature significantly increases the susceptibility of wheat plants to spot blotch causing pathogen Bipolaris sorokiniana. Two PGPR Bacillus safensis (W10) and Ochrobactrum pseudogrignonense (IP8) isolated from wheat (Triticum aestivum L.) and blady grass (Imperata cylindrical L.) rhizophere respectively, showing in vitro antagonistic activity against Bipolaris sorokiniana were tested for growth promotion and induction of resistance against spot blotch in wheat. GC-MS analysis showed that Bacillus safensis (W10) and Ochrobactrum pseudogrignonense (IP8) produced antifungal and antimicrobial compounds in culture. Seed priming with these two bacteria significantly increase growth, modulate antioxidative signaling and induce resistance and eventually reduce disease incidence in wheat plants at optimum as well as elevated temperature which was further confirmed by indirect immunofluorescence assay using polyclonal antibody raised against Bipolaris sorokiniana. Application of the PGPR led to enhancement in activities of plant defense enzymes- phenylalanine ammonia lyase, peroxidase, chitinase and β-1,3 glucanase in infected leaves. Immunolocalization of chitinase and β-1,3 glucanase in PGPR primed and pathogen inoculated leaf tissue was further confirmed by transmission electron microscopy using PAb of chitinase, β-1,3 glucanase and gold labelled conjugates. Activity of ascorbate-glutathione redox cycle related enzymes such as ascorbate peroxidase, superoxide dismutase and glutathione reductase along with antioxidants such as carotenoids, glutathione and ascorbate and osmolytes like proline and glycine betain accumulation were also increased during disease development in PGPR primed plant in comparison to unprimed plants at high temperature. Real-time PCR analysis revealed enhanced expression of defense genes- chalcone synthase and phenyl alanineammonia lyase. Over expression of heat shock proteins like HSP 70, small HSP 26.3 and heat shock factor HsfA3 in PGPR primed plants effectively protect plants against spot blotch infection at elevated temperature as compared with control plants. Our results revealed dynamic biochemical cross talk between elevated temperature and spot blotch disease development and furthermore highlight PGPR mediated array of antioxidative and molecular alterations responsible for induction of resistance against spot blotch disease at elevated temperature which seems to be associated with up-regulation of defense genes, heat shock proteins and heat shock factors, less ROS production, membrane damage, increased expression of redox enzymes and accumulation of osmolytes and antioxidants.

Keywords: antioxidative enzymes, defense enzymes, elevated temperature, heat shock proteins, PGPR, Real-Time PCR, spot blotch, wheat

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Authors: Ayman Hijazi, Witold Kwapinski, J. J. Leahy

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Finding a sustainable alternative energy to fossil fuel is an urgent need as various environmental challenges in the world arise. Therefore, formic acid (FA) decomposition has been an attractive field that lies at the center of biomass platform, comprising a potential pool of hydrogen energy that stands as a new energy vector. Liquid FA features considerable volumetric energy density of 6.4 MJ/L and a specific energy density of 5.3 MJ/Kg that qualifies it in the prime seat as an energy source for transportation infrastructure. Additionally, the increasing research interest in FA decomposition is driven by the need of in-situ H2 production, which plays a key role in the hydrogenation reactions of biomass into higher value components. It is reported elsewhere in literature that catalytic decomposition of FA is usually performed in poorly designed setup using simple glassware under magnetic stirring, thus demanding further energy investment to retain the used catalyst. it work suggests an approach that integrates designing a novel catalyst featuring magnetic property with a robust setup that minimizes experimental & measurement discrepancies. One of the most prominent active species for dehydrogenation/hydrogenation of biomass compounds is palladium. Accordingly, we investigate the potential of engrafting palladium metal onto functionalized magnetic nanoparticles as a heterogeneous catalyst to favor the production of CO-free H2 gas from FA. Using ordinary magnet to collect the spent catalyst renders core-shell magnetic nanoparticles as the backbone of the process. Catalytic experiments were performed in a jacketed batch reactor equipped with an overhead stirrer under inert medium. Through a novel approach, FA is charged into the reactor via high-pressure positive displacement pump at steady state conditions. The produced gas (H2+CO2) was measured by connecting the gas outlet to a measuring system based on the amount of the displaced water. The novelty of this work lies in designing a very responsive catalyst, pumping consistent amount of FA into a sealed reactor running at steady state mild temperatures, and continuous gas measurement, along with collecting the used catalyst without the need for centrifugation. Catalyst characterization using TEM, XRD, SEM, and CHN elemental analyzer provided us with details of catalyst preparation and facilitated new venues to alter the nanostructure of the catalyst framework. Consequently, the introduction of amine groups has led to appreciable improvements in terms of dispersion of the doped metals and eventually attaining nearly complete conversion (100%) of FA after 7 hours. The relative importance of the process parameters such as temperature (35-85°C), stirring speed (150-450rpm), catalyst loading (50-200mgr.), and Pd doping ratio (0.75-1.80wt.%) on gas yield was assessed by a Taguchi design-of-experiment based model. Experimental results showed that operating at lower temperature range (35-50°C) yielded more gas while the catalyst loading and Pd doping wt.% were found to be the most significant factors with a P-values 0.026 & 0.031, respectively.

Keywords: formic acid decomposition, green catalysis, hydrogen, mesoporous silica, process optimization, nanoparticles

Procedia PDF Downloads 44

Authors: Nadia Yaghoobi, Seyed Majid Esmaeilzadeh

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Due to advancements in wireless communication, new sensor capabilities have been created. In addition to the automation industry, the Internet of Things (IoT) has been used in environmental issues and has provided the possibility of communication between different devices for data collection and exchange. Water quality depends on many factors which are essential for maintaining the minimum sustainability of water. Regarding the great dependence of fishes on the quality of the aquatic environment, water quality can directly affect their activity. Therefore, monitoring water quality is an important issue to consider, especially in the fish farming industry. The conventional method of water quality testing is to collect water samples manually and send them to a laboratory for testing and analysis. This time-consuming method is a waste of manpower and is not cost-effective. The water quality measurement system implemented in this project monitors water quality in real-time through various sensors (parameters: water temperature, water level, dissolved oxygen, humidity and ambient temperature, water turbidity, PH). The Wi-Fi module, ESP8266, transmits data collected by sensors wirelessly to ThingSpeak and the smartphone app. Also, with the help of these instantaneous data, water temperature and water level can be controlled by using a heater and a water pump, respectively. This system can have a detailed study of the pollution and condition of water resources and can provide an environment for safe fish farming.

Keywords: dissolved oxygen, IoT, monitoring, ThingSpeak, water level, water quality, WiFi module

Procedia PDF Downloads 184

Authors: Amina Ben Abla, Sylvie Changotade, Geraldine Rohman, Guilhem Boeuf, Cyrine Dridi, Ahmed Elmarjou, Florence Dufour, Didier Lutomski, Abdellatif Elm’semi

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Understanding cell adhesion and interaction with the extracellular matrix is essential for biomedical and biotechnological applications, including the development of biomaterials. In recent years, numerous biomaterials have emerged and were used in the field of tissue engineering. Nevertheless, the lack of interaction of biomaterials with cells still limits their bio-integration. Thus, the design of bioactive biomaterials to improve cell attachment and proliferation is of growing interest. In this study, bio-functionalized material was developed combining a synthetic polymer scaffold surface with selected domains of type III human fibronectin (FNIII-DOM) to promote cell adhesion and proliferation. Bioadhesive ligand includes cell-binding domains of human fibronectin, a major ECM protein that interacts with a variety of integrins cell-surface receptors, and ECM proteins through specific binding domains were engineered. FNIII-DOM was produced in bacterial system E. coli in 5L fermentor with a high yield level reaching 20mg/L. Bioactivity of the produced fragment was validated by studying cellular adhesion of human cells. The adsorption and immobilization of FNIII-DOM onto the polymer scaffold were evaluated in order to develop an innovative biomaterial.

Keywords: biomaterials, cellular adhesion, fibronectin, tissue engineering

Procedia PDF Downloads 135

Authors: Caiyun Liu, A. Hernandez-Manas, N. Grimi, E. Vorobiev

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Drying is one of the most used methods for food preservation, which extend shelf life of food and makes their transportation, storage and packaging easier and more economic. The commonly dried method is hot air drying. However, its disadvantages are low energy efficiency and long drying times. Because of the high temperature during the hot air drying, the undesirable changes in pigments, vitamins and flavoring agents occur which result in degradation of the quality parameters of the product. Drying process can also cause shrinkage, case hardening, dark color, browning, loss of nutrients and others. Recently, new processes were developed in order to avoid these problems. For example, the application of pulsed electric field provokes cell membrane permeabilisation, which increases the drying kinetics and moisture diffusion coefficient. Microwave drying technology has also several advantages over conventional hot air drying, such as higher drying rates and thermal efficiency, shorter drying time, significantly improved product quality and nutritional value. Rehydration kinetics of dried product is a very important characteristic of dried products. Current research has indicated that the rehydration ratio and the coefficient of rehydration are dependent on the processing conditions of drying. The present study compares the efficiency of two processes (1: room temperature air drying, 2: microwave/air drying) in terms of drying rate, product quality and rehydration ratio. In this work, potato slices (≈2.2g) with a thickness of 2 mm and diameter of 33mm were placed in the microwave chamber and dried. Drying kinetics and drying rates of different methods were determined. The process parameters included inlet air velocity (1 m/s, 1.5 m/s, 2 m/s) and microwave power (50 W, 100 W, 200 W and 250 W) were studied. The evolution of temperature during microwave drying was measured. The drying power had a strong effect on drying rate, and the microwave-air drying resulted in 93% decrease in the drying time when the air velocity was 2 m/s and the power of microwave was 250 W. Based on Lewis model, drying rate constants (kDR) were determined. It was observed an increase from kDR=0.0002 s-1 to kDR=0.0032 s-1 of air velocity of 2 m/s and microwave/air (at 2m/s and 250W) respectively. The effective moisture diffusivity was calculated by using Fick's law. The results show an increase of effective moisture diffusivity from 7.52×10-11 to 2.64×10-9 m2.s-1 for air velocity of 2 m/s and microwave/air (at 2m/s and 250W) respectively. The temperature of the potato slices increased for higher microwaves power, but decreased for higher air velocity. The rehydration ratio, defined as the weight of the the sample after rehydration per the weight of dried sample, was determined at different water temperatures (25℃, 50℃, 75℃). The rehydration ratio increased with the water temperature and reached its maximum at the following conditions: 200 W for the microwave power, 2 m/s for the air velocity and 75°C for the water temperature. The present study shows the interest of microwave drying for the food preservation.

Keywords: drying, microwave, potato, rehydration

Procedia PDF Downloads 264

Authors: Zwalnan Selfa Johnson, Caleb Nanchen Nimyel, Gideon Duvuna Ayuba

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Air conditioning accounts for a significant share of the overall energy consumed in residential buildings. Solar thermal gains in buildings account for a significant component of the air conditioning load in buildings. This study compares the solar thermal gain and air conditioning load of a proposed building design with a typical conventional building in the climatic conditions of Jos, Nigeria, using a combined experimental and computational method using TRNSYS software. According to the findings of this study, the proposed design building's annual average solar thermal gains are lower compared to the reference building's average solar heat gains. The study case building's decreased solar heat gain is mostly attributable to the lower temperature of the building zones because of the greater building volume and lower fenestration ratio (ratio external opening area to the area of the external walls). This result shows that the proposed building design adjusts to the local climate better than the standard conventional construction in Jos to maintain a suitable temperature within the building. This finding means that the air-conditioning electrical energy consumption per volume of the proposed building design will be lower than that of a conventional building design.

Keywords: solar heat gain, building zone, cooling energy, air conditioning, zone temperature

Procedia PDF Downloads 83

Authors: Ana Maria Muț, Georgeta Coneac, Ioana Olariu, Ștefana Avram, Ioana Zinuca Pavel, Ionela Daliana Minda, Lavinia Vlaia, Cristina Adriana Dehelean, Corina Danciu

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Oregano essential oil is obtained from different parts of the plant Origanum vulgare (fam. Lamiaceae) and carvacrol and thymol are primary components, widely recognized for their antimicrobial activity, as well as their antiviral and antifungal properties. Poloxamers are triblock copolymers (Pluronic®), formed of three non-ionic blocks with a hydrophobic polyoxypropylene central chain flanked by two polyoxyethylene hydrophilic chains. They are known for their biocompatibility, sensitivity to temperature changes (sol-to-gel transition of aqueous solution with temperature increase), but also for their amphiphilic and surface active nature determining the formation of micelles, useful for solubilization of different hydrophobic compounds such as the terpenes and terpenoids contained in essential oils. Thus, these polymers, listed in European and US Pharmacopoeia and approved by FDA, are widely used as solubilizers and gelling agents for various pharmaceutical preparations, including topical hydrogels. The aim of this study was to investigate the posibility of solubilizing oregano essential oil (OEO) in polymeric micelles using polyoxypropylene (PPO)-polyoxyethylene (PEO)-polyoxypropylene (PPO) triblock polymers to obtain semisolid systems suitable for topical application. A formulation screening was performed, using Pluronic® F-127 in concentration of 20%, Pluronic® L-31, Pluronic® L-61 and Pluronic® L-62 in concentration of 0.5%, 0.8% respectively 1% to obtain the polymeric micelles-based systems. Then, to each selected system, with or without 10% absolute ethanol, 5% or 8% OEO was added. The obtained transparent poloxamer-based hydrogels containing solubilized OEO were further evaluated for pH, rheological characteristics (flow behaviour, viscosity, consistency and spreadability), using consacrated techniques like potentiometric titration, stationary shear flow test, penetrometric method and parallel plate method. Also, in vitro release and permeation of carvacrol from the hydrogels was carried out, using vertical diffusion cells and synthetic hydrophilic membrane and porcine skin respectively. The pH values and rheological features of all tested formulations were in accordance with official requirements for semisolid cutaneous preparations. But, the formulation containing 0.8% Pluronic® L-31, 10% absolute ethanol, 8% OEO and water and the formulation with 1% Pluronic® L-31, 5% OEO and water, produced the highest cumulative amounts of carvacrol released/permeated through the membrane. The present study demonstrated that oregano essential oil can be successfully solubilized in the investigated poloxamer-based hydrogels. These systems can be further investigated as potential topical therapy for cutaneous papillomas. Funding: This research was funded by Project PN-III-P1-1.1-TE2019-0130, Contract number TE47, Romania.

Keywords: oregano essential oil, carvacrol, poloxamer, topical hydrogels

Procedia PDF Downloads 108

Authors: Laura Gantley, Vanessa M. Conn, Stuart Webb, Kirsty Kirk, Marta Gabryelska, Duncan Holds, Brett W. Stringer, Simon J. Conn

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Trinucleotide repeat disorders comprise ~20 severe, inherited human neuromuscular and neurodegenerative disorders, which are a result of an abnormal expansion of repetitive sequences in the DNA. The most common of these, Huntington’s disease, results from the expansion of the CAG repeat region in exon 1 of the HTT gene via an unknown mechanism. Non-coding RNAs have been implicated in the initiation and progression of many diseases; thus, we focus on one circular RNA (circRNA) molecule arising from non-canonical splicing (back splicing) of HTT pre-mRNA. This circRNA and its mouse orthologue were transgenically overexpressed in human cells (SHSY-5Y and HEK293T) and mouse cells (Mb1), respectively. High-content imaging and flow cytometry demonstrated the overexpression of this circRNA reduces cell proliferation, reduces nuclear size independent of cellular size, and alters cell cycle progression. Analysis of protein by western blot and immunofluorescence demonstrated no change to HTT protein levels but altered nuclear-cytoplasmic distribution without impacting the expansion of the HTT repeat region. As these phenotypic and genotypic changes are found in Huntington’s disease patients, these results may suggest that this circRNA may play a functional role in the progression of Huntington’s disease.

Keywords: cell biology, circular RNAs, Huntington’s disease, molecular biology, neurodegenerative disorders

Procedia PDF Downloads 93

Authors: Yoftahe Nigussie Worku

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This report unveils a meticulous project focused on the design intricacies of a Fire Tube Boiler tailored for the efficient generation of saturated steam. The overarching objective is to produce 2000kg/h of saturated steam at 12-bar design pressure, achieved through the development of an advanced fire tube boiler. This design is meticulously crafted to harmonize cost-effectiveness and parameter refinement, with a keen emphasis on material selection for component parts, construction materials, and production methods throughout the analytical phases. The analytical process involves iterative calculations, utilizing pertinent formulas to optimize design parameters, including the selection of tube diameters and overall heat transfer coefficients. The boiler configuration incorporates two passes, a strategic choice influenced by tube and shell size considerations. The utilization of heavy oil fuel no. 6, with a higher heating value of 44000kJ/kg and a lower heating value of 41300kJ/kg, results in a fuel consumption of 140.37kg/hr. The boiler achieves an impressive heat output of 1610kW with an efficiency rating of 85.25%. The fluid flow pattern within the boiler adopts a cross-flow arrangement strategically chosen for inherent advantages. Internally, the welding of the tube sheet to the shell, secured by gaskets and welds, ensures structural integrity. The shell design adheres to European Standard code sections for pressure vessels, encompassing considerations for weight, supplementary accessories (lifting lugs, openings, ends, manhole), and detailed assembly drawings. This research represents a significant stride in optimizing fire tube boiler technology, balancing efficiency and safety considerations in the pursuit of enhanced saturated steam production.

Keywords: fire tube, saturated steam, material selection, efficiency

Procedia PDF Downloads 66

Authors: Jungkyun Na, Jaesang Lee, Yang Mo Koo

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

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

Procedia PDF Downloads 211

Authors: Amjad Abdullah, Amjad Yahya, Bushra Aljohani, Amani Alghamdi

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Change point detection is an important part of data analysis. The presence of a change point refers to a significant change in the behavior of a time series. In this article, we examine the detection of multiple change points of parameters of the exponential Lomax distribution, which is broad and flexible compared with other distributions while fitting data. We used the Schwarz information criterion and binary segmentation to detect multiple change points in publicly available data on the average temperature in the ozone layer. The change points were successfully located.

Keywords: binary segmentation, change point, exponentialLomax distribution, information criterion

Procedia PDF Downloads 168

Authors: Coriolano Salvini

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The increasing utilization of renewable energy sources for electric power production calls for the introduction of energy storage systems to match the electric demand along the time. Although many countries are pursuing as a final goal a “decarbonized” electrical system, in the next decades the traditional fossil fuel fed power plant still will play a relevant role in fulfilling the electric demand. Presently, such plants provide grid ancillary services (frequency control, grid balance, reserve, etc.) by adapting the output power to the grid requirements. An interesting option is represented by the possibility to use traditional plants to improve the grid storage capabilities. The present paper is addressed to small-medium size systems suited for distributed energy storage. The proposed Energy Storage System (ESS) is based on a Compressed Air Energy Storage (CAES) integrated into a Gas-Steam Combined Cycle (GSCC) or a Gas Turbine based CHP plants. The systems can be incorporated in an ex novo built plant or added to an already existing one. To avoid any geological restriction related to the availability of natural compressed air reservoirs, artificial storage is addressed. During the charging phase, electric power is absorbed from the grid by an electric driven intercooled/aftercooled compressor. In the course of the discharge phase, the compressed stored air is sent to a heat transfer device fed by hot gas taken upstream the Heat Recovery Steam Generator (HRSG) and subsequently expanded for power production. To maximize the output power, a staged reheated expansion process is adopted. The specific power production related to the kilogram per second of exhaust gas used to heat the stored air is two/three times larger than that achieved if the gas were used to produce steam in the HRSG. As a result, a relevant power augmentation is attained with respect to normal GSCC plant operations without additional use of fuel. Therefore, the excess of output power can be considered “fuel free” and the storage system can be compared to “pure” ESSs such as electrochemical, pumped hydro or adiabatic CAES. Representative cases featured by different power absorption, production capability, and storage capacity have been taken into consideration. For each case, a technical optimization aimed at maximizing the storage efficiency has been carried out. On the basis of the resulting storage pressure and volume, number of compression and expansion stages, air heater arrangement and process quantities found for each case, a cost estimation of the storage systems has been performed. Storage efficiencies from 0.6 to 0.7 have been assessed. Capital costs in the range of 400-800 €/kW and 500-1000 €/kWh have been estimated. Such figures are similar or lower to those featuring alternative storage technologies.

Keywords: artificial air storage reservoir, compressed air energy storage (CAES), gas steam combined cycle (GSCC), techno-economic analysis

Procedia PDF Downloads 204

Authors: Miaomiao Zhang, Sabrina Beckmann, Haluk Ertan, Rocky Chau, Mike Manefield

Abstract:

Phenazines are a large class of nitrogen-containing aromatic heterocyclic compounds, which are almost exclusively produced by bacteria from diverse genera including Pseudomonas and Streptomyces. Phenazine-1-carboxylic acid (PCA) as one of 'core' phenazines are converted from chorismic acid before modified to other phenazine derivatives in different cells. Phenazines have attracted enormous interests because of their multiple roles on biocontrol, bacterial interaction, biofilm formation and fitness of their producers. However, in spite of ecological importance, degradation as a part of phenazines’ fate only have extremely limited attention now. Here, to isolate PCA-degrading bacteria, 200 mg L-1 PCA was supplied as sole carbon, nitrogen and energy source in minimal mineral medium. Quantitative PCR and Reverse-transcript PCR were employed to study abundance and activity of functional gene MFORT 16269 in PCA degradation, respectively. Intermediates and products of PCA degradation were identified with LC-MS/MS. After enrichment and isolation, a PCA-degrading strain was selected from soil and was designated as Rhodanobacter sp. PCA2 based on full 16S rRNA sequencing. As determined by HPLC, strain PCA2 consumed 200 mg L-1 (836 µM) PCA at a rate of 17.4 µM h-1, accompanying with significant cells yield from 1.92 × 105 to 3.11 × 106 cells per mL. Strain PCA2 was capable of degrading other phenazines as well, including phenazine (4.27 µM h-1), pyocyanin (2.72 µM h-1), neutral red (1.30 µM h-1) and 1-hydroxyphenazine (0.55 µM h-1). Moreover, during the incubation, transcript copies of MFORT 16269 gene increased significantly from 2.13 × 106 to 8.82 × 107 copies mL-1, which was 2.77 times faster than that of the corresponding gene copy number (2.20 × 106 to 3.32 × 107 copies mL-1), indicating that MFORT 16269 gene was activated and played roles on PCA degradation. As analyzed by LC-MS/MS, decarboxylation from the ring structure was determined as the first step of PCA degradation, followed by cleavage of nitrogen-containing ring by dioxygenase which catalyzed phenazine to nitrosobenzene. Subsequently, phenylhydroxylamine was detected after incubation for two days and was then transferred to aniline and catechol. Additionally, genomic and proteomic analyses were also carried out for strain PCA2. Overall, the findings presented here showed that a newly isolated strain Rhodanobacter sp. PCA2 was capable of degrading phenazines through decarboxylation and cleavage of nitrogen-containing ring, during which MFORT 16269 gene was activated and played important roles.

Keywords: decarboxylation, MFORT16269 gene, phenazine-1-carboxylic acid degradation, Rhodanobacter sp. PCA2

Procedia PDF Downloads 217