Search results for: vapor injection

Authors: Shantanu Prakash, Suruchi Shukla, Amita Jain

Abstract:

Introduction: The hepatitis C virus (HCV) is a major public health problem and a leading cause of chronic liver disease. Injection drug use and individuals receiving blood and blood products are the primary modes of HCV transmission. Our study aims to establish the prevalent genotypes/ subtypes of HCV circulating in Uttar Pradesh, North India, as reported from a tertiary care hospital. Methods: It is a retrospective observational analysis of consecutive 404 HCV RNA positive cases referred to our hospital during September 2014 to April 2017. The study was approved by an institutional ethics committee. Written informed consent was taken from each participant. Clinical and demographic details of these patients were recorded using predesigned questionnaires. All the laboratory testing was carried on stored serum sample of enrolled cases. Genotyping of all 404 strains was done by Sanger’s sequencing of the core region. The phylogenetic analysis of 179 HCV strains with high -quality sequencing data was performed. Results: The distribution of prevalent genotypes/ subtypes as noted in the present study was; Genotype (GT)1a [n-101(25%)], GT1b [n-12(2.9%)], GT1c [1(0.25%)], GT3a [275(68.07%)], GT3b [9(2.2%)], GT3g [2(0.49%)], GT3i [3(0.74%)], and GT4a [1(0.24%)]. HCV genotypes GT2, GT5 and GT6 were not detected from our region. Sequence analysis showed high genotypic variability in HCV GT3. Phylogenetic analysis showed that HCV GT3 and GT1 circulating in our region were related to Indian strains reported earlier. Conclusions: HCV genotypes 3a and 1a are commonest circulating genotypes in Uttar Pradesh (UP), India.

Keywords: Hepatitis C virus, genetic variation, bioinformatics, genotype, HCV

Procedia PDF Downloads 143

Authors: Youssef Wardeh, Elias Kinab, Pierre Rahme, Gilles Escadeillas, Stephane Ginestet

Abstract:

Urban heat islands designate a local phenomenon that appears in high density cities. This results in a rise ofambient temperature in the urban area compared to the neighboring rural area. Solar radiation plays an important role in this phenomenon since it is partially absorbed by the materials, especially roads and parking lots. Cool pavements constitute an innovative and promising technique to mitigate urban heat islands. The cool pavements studied in this work allow to limit the increase of the surface temperature, thanks to evaporation of the water conducted through capillary pores, from the humidified base to the surface exposed to solar radiation. However, the performance or the cooling capacity of a pavement sometimes remained difficult to characterize. In this work, a new definition of the cooling capacity of a pavement is presented, and a correlation between the latter and the hydrothermal properties of cool pavements is revealed. Firstly, several porous concrete pavements were characterized through their hydrothermal properties, which can be related to the cooling effect, such as albedo, thermal conductivity, water absorption, etc. Secondly, these pavements initially saturated and continuously supplied with water through their bases, were exposed to external solar radiation during three sunny summer days, and their surface temperatures were measured. For draining pavements, a strong second-degreepolynomial correlation(R² = 0.945) was found between the cooling capacity and the term, which reflects the interconnection of capillary water to the surface. Moreover, it was noticed that the cooling capacity reaches its maximum for an optimal range of capillary pores for which the capillary rise is stronger than gravity. For non-draining pavements, a good negative linear correlation (R² = 0.828) was obtained between the cooling capacity and the term, which expresses the ability to heat the capillary water by the energystored far from the surface, and, therefore, the dominance of the evaporation process by diffusion. The latest tests showed that this process is, however, likely to be disturbed by the material resistance to the water vapor diffusion.

Keywords: urban heat islands, cool pavement, cooling capacity, hydrothermal properties, evaporation

Procedia PDF Downloads 85

Authors: N. Prabavathy, R. Balasundaraprabhu, S. Shalini, Dhayalan Velauthapillai, S. Prasanna, N. Muthukumarasamy

Abstract:

Dye sensitized solar cell (DSSC) has become a significant research area due to their fundamental and scientific importance in the area of energy conversion. Synthetic dyes as sensitizer in DSSC are efficient and durable but they are costlier, toxic and have the tendency to degrade. Natural sensitizers contain plant pigments such as anthocyanin, carotenoid, flavonoid, and chlorophyll which promote light absorption as well as injection of charges to the conduction band of TiO2 through the sensitizer. But, the efficiency of natural dyes is not up to the mark mainly due to instability of the pigment such as anthocyanin. The stability issues in vitro are mainly due to the effect of solvents on extraction of anthocyanins and their respective pH. Taking this factor into consideration, in the present work, the anthocyanins were extracted from the flower Caesalpinia pulcherrima (C. pulcherrimma) with various solvents and their respective stability and pH values are discussed. The usage of citric acid as solvent to extract anthocyanin has shown good stability than other solvents. It also helps in enhancing the sensitization properties of anthocyanins with Titanium dioxide (TiO2) nanorods. The IPCE spectra show higher photovoltaic performance for dye sensitized TiO2nanorods using citric acid as solvent. The natural DSSC using citric acid as solvent shows a higher efficiency compared to other solvents. Hence citric acid performs to be a safe solvent for natural DSSC in boosting the photovoltaic performance and maintaining the stability of anthocyanins.

Keywords: Caesalpinia pulcherrima, citric acid, dye sensitized solar cells, TiO₂ nanorods

Procedia PDF Downloads 277

Authors: Nadia Chougui, Nawal Makhloufi, Farouk Rezgui, Elias Benramdane, Carmen S. R. Freire, Carla Vilela, Armando J. D. Silvestre

Abstract:

Native to Mexico, Opuntia ficus-indica was introduced in southern Spain, and thereafter, it was spread throughout the Mediterranean Basin by the Spanish conquerors in the 16th and 17th centuries. O. ficus-indica is a tropical and subtropical plant able to grow in arid and semi-arid regions, such as the Mediterranean and Central America regions. The culture of Opuntia covers about 200,000 ha in North Africa. This tree is used against soil erosion and desertification for fruit production and is encouraged to promote the livestock sector. It has recently received ever-increasing attention from researchers worldwide for the multivalent pharmaceutical and cosmetical potential of its different compartments (fruits, seeds, cladodes). The present study investigated the elaboration by casting method and characterization of new biodegradable films composed of cladodes powder (CP) of the plant raw material mentioned above, and a marine seaweed derivative, namely agar (A). The effect of glycerol concentration on the properties of the films was evaluated at four different contents (30, 40, 50 and 60 wt.%). The films present UV-blocking properties, thermal stability as well as moderate mechanical performance and water vapor transmission rate (WVTR). The results point to an increase in thickness, elongation at break, moisture content, water solubility, and WVTR with increasing glycerol content. On the contrary, Young’s modulus, tensile strength and contact angle decreased as glycerol concentration increased. The best combination is obtained for the film with 30% glycerol, based on an intermediate compromise between physical, mechanical, thermal and barrier properties. All these outcomes express the potentiality of the powder obtained from grinding the OFI cladodes as raw material to produce low-cost films for the development of sustainable packaging materials.

Keywords: Opuntia ficus-indica cladodes powder, agar, biobased films, effect of plasticizer, sustainable packaging

Procedia PDF Downloads 60

Authors: Samad Lotfollahzadeh

Abstract:

Escherichia coli (E.coli) is the most isolated bacteria from blood circulation of septicemic calves. Given the prevalence of septicemia in animals and its economic importance in veterinary practice, better understanding of changes in clinical signs following disease, may contribute to early detection of the disorder. The present study has been carried out to detect changes of clinical signs in induced sepsis in calves with E.coli. Colisepticemia has been induced in 10 twenty-day old healthy Holstein- Frisian calves with intravenous injection of 1.5 X 109 colony forming units (cfu) of O111: H8 strain of E.coli. Clinical signs including rectal temperature, heart rate, respiratory rate, shock, appetite, sucking reflex, feces consistency, general behavior, dehydration and standing ability were recorded in experimental calves during 24 hours after induction of colisepticemia. Blood culture was also carried out from calves four times during the experiment. ANOVA with repeated measure is used to see changes of calves’ clinical signs to experimental colisepticemia, and values of P≤ 0.05 was considered statistically significant. Mean values of rectal temperature and heart rate as well as median values of respiratory rate, appetite, suckling reflex, standing ability and feces consistency of experimental calves increased significantly during the study (P<0.05). In the present study, median value of shock score was not significantly increased in experimental calves (P> 0.05). The results of present study showed that total score of clinical signs in calves with experimental colisepticemia increased significantly, although the score of some clinical signs such as shock did not change significantly.

Keywords: calves, clinical signs scoring, E. coli O111:H8, experimental colisepticemia

Procedia PDF Downloads 365

Authors: Malinwo Estone Ayikpa

Abstract:

With the rapid increase of grid-connected PV systems over the last decades, genuine challenges have arisen for engineers and professionals of energy field in the planning and operation of existing distribution networks with the integration of new generation sources. However, the conventional distribution network, in its design was not expected to receive other generation outside the main power supply. The tools generally used to analyze the networks become inefficient and cannot take into account all the constraints related to the operation of grid-connected PV systems. Some of these constraints are voltage control difficulty, reverse power flow, and especially voltage unbalance which could be due to the poor distribution of single-phase PV systems in the network. In order to analyze the impact of the connection of small and large number of PV systems to the distribution networks, this paper presents an efficient optimization tool that minimizes voltage unbalance in three-phase distribution networks with active and reactive power injections from the allocation of single-phase and three-phase PV plants. Reactive power can be generated or absorbed using the available capacity and the adjustable power factor of the inverter. Good reduction of voltage unbalance can be achieved by reactive power control of the PV systems. The presented tool is based on the three-phase current injection method and the PV systems are modeled via an equivalent circuit. The primal-dual interior point method is used to obtain the optimal operating points for the systems.

Keywords: Photovoltaic system, Primal-dual interior point method, Three-phase optimal power flow, Voltage unbalance

Procedia PDF Downloads 325

Authors: Yi Zhang, Yuan Tian, Jiehua Chen, Sihong Gu

Abstract:

Chip-scale spin-exchange relaxation free (SERF) atomic magnetometer makes use of millimeter-scale vapor cells micro-fabricated by Micro-electromechanical Systems (MEMS) technique and SERF mechanism, resulting in the characteristics of high spatial resolution and high sensitivity. It is useful for biomagnetic imaging including magnetoencephalography and magnetocardiography. In a prevailing scheme, circularly polarized on-resonance laser beam is adapted for both pumping and probing the atomic polarization. And the magnetic-field-sensitive signal is extracted by transmission laser intensity enhancement as a result of atomic polarization increase on zero field level crossing resonance. The scheme is very suitable for integration, however, the laser amplitude modulation (AM) noise and laser frequency modulation to amplitude modulation (FM-AM) noise is superimposed on the photon shot noise reducing the signal to noise ratio (SNR). To suppress AM and FM-AM noise the paper puts forward a novel scheme which adopts circularly polarized on-resonance light pumping and linearly polarized frequency-detuning laser probing. The transmission beam is divided into transmission and reflection beams by a polarization analyzer, the angle between the analyzer's transmission polarization axis and frequency-detuning laser polarization direction is set to 45°. The magnetic-field-sensitive signal is extracted by polarization rotation enhancement of frequency-detuning laser which induces two beams intensity difference increase as the atomic polarization increases. Therefore, AM and FM-AM noise in two beams are common-mode and can be almost entirely canceled by differential detection. We have carried out an experiment to study our scheme. The experiment reveals that the noise in the differential signal is obviously smaller than that in each beam. The scheme is promising to be applied for developing more sensitive chip-scale magnetometer.

Keywords: atomic magnetometer, chip scale, differential detection, spin-exchange relaxation free

Procedia PDF Downloads 161

Authors: Waqar Ahmad Butt, Gholamreza Vakili Nezhaad, Ali Soud Al Bemani, Yahya Al Wahaibi

Abstract:

Minimum miscibility pressure (MMP) plays a great role in determining the displacement efficiency of different gas injection processes. Experimental techniques for MMP determination include industrially recommended slim tube, vanishing interfacial tension (VIT) and rising bubble apparatus (RBA). In this paper, MMP measurement study using slim tube and VIT experimental techniques for two different crude oil samples (M and N) both in live and stock tank oil forms is being presented. VIT measured MMP values for both 'M' and 'N' live crude oils were close to slim tube determined MMP values with 6.4 and 5 % deviation respectively. Whereas for both oil samples in stock tank oil form, VIT measured MMP showed a higher unacceptable deviation from slim tube determined MMP. This higher difference appears to be related to high stabilized crude oil heavier fraction and lack of multiple contacts miscibility. None of the different nine deployed crude oil and CO2 MMP computing correlations could result in reliable MMP, close to slim tube determined MMP. Since VIT determined MMP values for both considered live crude oils are in close match with slim tube determined MMP values, it confirms reliable, reproducible, rapid and cheap alternative for live crude oil MMP determination. Whereas VIT MMP determination for stock tank oil case needed further investigation about stabilization / destabilization mechanism of oil heavier ends and multiple contacts miscibility development issues.

Keywords: minimum miscibility pressure, interfacial tension, multiple contacts miscibility, heavier ends

Procedia PDF Downloads 261

Authors: Mehdi Abbasi, Shadan Navid, Mohammad Pourahmadi, M. Majidi Zolbin

Abstract:

We have recently reported that melatonin as antioxidant enhances the efficacy of colonization of spermatogonial stem cells (SSCs). Melatonin as an antioxidant plays a vital role in the development of SSCs in vitro. This study aimed to investigate evaluation of sertoli cells and melatonin simultaneously on SSC proliferation following transplantation to testis of adult mouse busulfan-treated azoospermia model. SSCs and sertoli cells were isolated from the testes of three to six-day old male mice.To determine the purity, Flow cytometry technique using PLZF antibody were evaluated. Isolated testicular cells were cultured in αMEM medium in the absence (control group) or presence (experimental group) of sertoli cells and melatonin extract for 2 weeks. We then transplanted SSCs by injection into the azoospermia mice model. Higher viability, proliferation, and Id4, Plzf, expression were observed in the presence of simultaneous sertoli cells and melatonin in vitro. Moreover, immunocytochemistry results showed higher Oct4 expression in this group. Eight weeks after transplantation, injected cells were localized at the base of seminiferous tubules in the recipient testes. The number of spermatogonia and the weight of testis were higher in the experimental group relative to control group. The results of our study suggest that this new protocol can increase the transplantation of these cells can be useful in the treatment of male infertility.

Keywords: colonization, melatonin, spermatogonial stem cell, transplantation

Procedia PDF Downloads 161

Authors: Ntalamagka N., Sanchis-Benlloch P. J., Mayoral-Serrano R., Tena-Medialdea J., García-March J. R.

Abstract:

The pen shell Pinna nobilis population has declined dramatically since 2016 due to die-off events observed in the whole extent of the Mediterranean Sea associated with the protozoan Haplosporidium pinnae. As of 2019, it is considered a critically endangered species. Due to its ecological importance and its endangered status, several initiatives have been developed for its salvation and recovery. This research is an effort to understand and control its reproduction under captivity. As a limited number of Pinna nobilis individuals could be used for experimentation, the possibility of using the Pinna rudis as a model animal was explored. The molecular mechanism that regulates the reproduction of both species is unknown; consequently, transcriptomic analysis was performed to identify neuropeptides that are expressed in the key regulatory tissues of the visceral ganglia and gonads of both species. Neuropeptides form an important group of signaling peptides that regulate reproductive, behavioral and physiological functions in molluscs. In total, 17 neuropeptide precursors were identified in P. nobilis and 14 in P. rudis transcriptomes; 14 of them were identical in both species. This affinity verified the genetic similarity of these species at the reproduction level. APGWamide, buccalin, ELH and GnRH were tested in P. rudis and demonstrated their capacity to advance gonadal maturation and trigger spawning while spawning was recorded in P. nobilis after the usage of APGWamide and buccalin. The neuropeptides were administered using intramuscular injection and cholesterol implants following relative literature as well as a new method was developed for external administration without the use of anesthesia using a mathematical model. The know-how of this research will not only lead to the survival of the species but also will narrow the horizons of broodstock conditioning of other similar species.

Keywords: neuropeptides, Pinna nobilis, reproduction, transcriptomics

Procedia PDF Downloads 84

Authors: Aschalew C. Workneh, K. S. Hari Prasad, C. S. P. Ojha

Abstract:

The crop water stress index (CWSI) is a cost-effective, non-destructive, and simple technique for tracking the start of crop water stress. This study investigated the feasibility of CWSI derived from canopy temperature to detect the water status of wheat crops. Artificial intelligence (AI) techniques have become increasingly popular in recent years for determining CWSI. In this study, the performance of two AI techniques, adaptive neuro-fuzzy inference system (ANFIS) and self-organizing maps (SOM), are compared while determining the CWSI of paddy crops. Field experiments were conducted for varying irrigation water applications during two seasons in 2022 and 2023 at the irrigation field laboratory at the Civil Engineering Department, Indian Institute of Technology Roorkee, India. The ANFIS and SOM-simulated CWSI values were compared with the experimentally calculated CWSI (EP-CWSI). Multiple regression analysis was used to determine the upper and lower CWSI baselines. The upper CWSI baseline was found to be a function of crop height and wind speed, while the lower CWSI baseline was a function of crop height, air vapor pressure deficit, and wind speed. The performance of ANFIS and SOM were compared based on mean absolute error (MAE), mean bias error (MBE), root mean squared error (RMSE), index of agreement (d), Nash-Sutcliffe efficiency (NSE), and coefficient of correlation (R²). Both models successfully estimated the CWSI of the paddy crop with higher correlation coefficients and lower statistical errors. However, the ANFIS (R²=0.81, NSE=0.73, d=0.94, RMSE=0.04, MAE= 0.00-1.76 and MBE=-2.13-1.32) outperformed the SOM model (R²=0.77, NSE=0.68, d=0.90, RMSE=0.05, MAE= 0.00-2.13 and MBE=-2.29-1.45). Overall, the results suggest that ANFIS is a reliable tool for accurately determining CWSI in wheat crops compared to SOM.

Keywords: adaptive neuro-fuzzy inference system, canopy temperature, crop water stress index, self-organizing map, wheat

Procedia PDF Downloads 40

Authors: Carlos Alberto Ríos Reyes

Abstract:

Traditionally, clays have been considered as one of the main problems in the flow of fluids in hydrocarbon reservoirs. However, there is not known the significance of zeolites formed from the reactivity of clays and their effect not only on the costs of operations carried out by the oil industry in the world but also on production. The present work focused on understanding the interaction between clay minerals with brines and alkaline solutions used in the oil industry. For this, a comparative study was conducted where the reaction of sedimentary rocks under laboratory conditions was examined. Original and treated rocks were examined by X-ray powder diffraction (XRPD) and Scanning Electron Microscopy (SEM) to determine the changes that these rocks underwent upon contact with fluids of variable chemical composition. As a result, zeolite Linde Type A (LTA), sodalite (SOD), and cancrinite (CAN) can be formed after experimental work, which coincided with the dissolution of kaolinite and smectite. Results reveal that the Oil Industry should invest efforts and focus its gaze to understand at the pore scale the problem that could arise as a consequence of the clay-fluid interaction in hydrocarbon reservoir rocks due to the presence of clays in their porous system, as well as the formation of zeolites, which are better hydrocarbon absorbents. These issues could be generating losses in world production. We conclude that there is a critical situation that may be occurring in the stimulation of hydrocarbon reservoirs, where real solutions are necessary not only for the formulation of more efficient and effective injection fluids but also to contribute to the improvement of production and avoid considerable losses in operating costs.

Keywords: clay minerals, zeolites, rock-fluid interaction, experimental work, reactivity

Procedia PDF Downloads 69

Authors: A. Hadadi, M. Abdollahi, A. Dustmohammadi

Abstract:

The growing use of DGs in distribution networks provide many advantages and also cause new problems which should be anticipated and be solved with appropriate solutions. One of the problems is transient voltage drop and short circuit in the electrical network, in the presence of distributed generation - which can lead to instability. The appearance of the short circuit will cause loss of generator synchronism, even though if it would be able to recover synchronizing mode after removing faulty generator, it will be stable. In order to increase system reliability and generator lifetime, some strategies should be planned to apply even in some situations which a fault prevent generators from separation. In this paper, one fault current limiter is installed due to prevent DGs separation from the grid when fault occurs. Furthermore, an innovative objective function is applied to determine the impedance optimal amount of fault current limiter in order to improve transient stability of distributed generation. Fault current limiter can prevent generator rotor's sudden acceleration after fault occurrence and thereby improve the network transient stability by reducing the current flow in a fast and effective manner. In fact, by applying created impedance by fault current limiter when a short circuit happens on the path of current injection DG to the fault location, the critical fault clearing time improve remarkably. Therefore, protective relay has more time to clear fault and isolate the fault zone without any instability. Finally, different transient scenarios of connection plan sustainability of small scale synchronous generators to the distribution network are presented.

Keywords: critical clearing time, fault current limiter, synchronous generator, transient stability, transient states

Procedia PDF Downloads 186

Authors: M. Sangeetha, D. Chamundeeswari, C. Saravanababu, C. Rose, V. Gopal

Abstract:

Rheumatoid arthritis (RA) is a chronic, progressive, systemic inflammatory disorder affecting the synovial joints and typically producing symmetrical arthritis that leads to joint destruction, which is responsible for the deformity and disability. Despite improvements in the treatment of RA over the past decade, there still is a need for new therapeutic agents that are efficacious, less expensive, and free of severe adverse reactions. The present study aimed to investigate role of inflammatory markers in arthritic rats treated with ethanolic bark extract of Albizia procera. The protective effect of ethanolic bark extract of Albizia procera against complete Freund’s adjuvant (CFA) induced arthritis in rats. Arthritis was induced by an intradermal injection of 0.1 ml FCA in the foot pad of left hind limb of rats. ETBE (100 and 200 mg/kg b.wt./p.o) and the reference drug diclofenac (25 mg/kg b.wt./p.o) were administered to arthritic rats. Paw volume was measured for all the animals before inducing arthritis and thereafter once in seven days by using plethysmometer for 42 days. Gene expression of inflammatory markers such as IL-1β and IL-10 were investigated in paw tissues. Up regulation of IL-1β and Down regulation IL-10 were observed in CFA injected rats when compared to normal rats. ETBE attenuated these alterations dose dependently when compared to the vehicle treated rats. These results provide insights into the mechanism of anti-arthritic activity, and unravel potential therapeutic use of Albizia procera in arthritis.

Keywords: CFA-Complete Freund’s adjuvant, ETBE – ethanolic bark extract, IL- interleukins, RA-rheumatoid arthritis

Procedia PDF Downloads 271

Authors: Zi-Yan Liao, Shan-Yu Zhang, Ya-Xian Lin, Ya-Lun Lee, Shih-Chuan Huang, Hong-Ru Lin

Abstract:

Traditional wound dressings, such as gauze, bandages, etc., are easy to adhere to the tissue fluid exuded from the wound, causing secondary damage to the wound during removal. This study takes this as the idea to develop a hydrogel dressing, to explore that the dressing will not cause secondary damage to the wound when it is torn off, and at the same time, create an environment conducive to wound healing. First, the temperature-sensitive material N-isopropylacrylamide (NIPAAm) was used as the substrate. Due to its low mechanical properties, the hydrogel would break due to pulling during human activities. Polyvinyl alcohol (PVA) interpenetrates into it to enhance the mechanical properties, and a semi-interpenetration (semi-IPN) composed of poly(N-isopropylacrylamide) (PNIPAAm) and polyvinyl alcohol (PVA) was prepared by free radical polymerization. PNIPAAm was cross-linked with N,N'-methylenebisacrylamide (NMBA) in an ice bath in the presence of linear PVA, and tetramethylhexamethylenediamine (TEMED) was added as a promoter to speed up the gel formation. The polymerization stage was carried out at 16°C for 17 hours and washed with distilled water for three days after gel formation, and the water was changed several times in the middle to complete the preparation of semi-IPN hydrogel. Finally, various tests were used to analyze the effects of different ratios of PNIPAAm and PVA on semi-IPN hydrogels. In the swelling test, it was found that the maximum swelling ratio can reach about 50% under the environment of 21°C, and the higher the ratio of PVA, the more water can be absorbed. The saturated moisture content test results show that when more PVA is added, the higher saturated water content. The water vapor transmission rate test results show that the value of the semi-IPN hydrogel is about 57 g/m²/24hr, which is not much related to the proportion of PVA. It is found in the LCST test compared with the PNIPAAm hydrogel; the semi-IPN hydrogel possesses the same critical solution temperature (30-35°C). The semi-IPN hydrogel prepared in this study has a good effect on temperature response and has the characteristics of thermal sensitivity. It is expected that after improvement, it can be used in the treatment of surface wounds, replacing the traditional dressing shortcoming.

Keywords: hydrogel, N-isopropylacrylamide, polyvinyl alcohol, hydrogel wound dressing, semi-interpenetrating polymer network

Procedia PDF Downloads 69

Authors: Jianguo Chen, Fenggang Zang, Yu Yang, Liangang Zheng

Abstract:

Reactor Pressure Vessel (RPV) is an important security barrier in nuclear power plant. Crack like defects may be produced on RPV during the whole operation lifetime due to the harsh operation condition and irradiation embrittlement. During the severe loss of coolant accident, thermal shock happened as the injection of emergency cooling water into RPV, which results in re-pressurization of the vessel and very high tension stress on the vessel wall, this event called Pressurized Thermal Shock (PTS). Crack on the vessel wall may propagate even penetrate the vessel, so the safety of the RPV would undergo great challenge. Many assumptions in structure integrity evaluation make the result of deterministic fracture mechanics very conservative, which affect the operation lifetime of the plant. Actually, many parameters in the evaluation process, such as fracture toughness and nil-ductility transition temperature, have statistical distribution characteristics. So it is necessary to assess the structural integrity of RPV subjected to PTS event by means of Probabilistic Fracture Mechanics (PFM). Structure integrity evaluation methods of RPV subjected to PTS event are summarized firstly, then evaluation method based on probabilistic fracture mechanics are presented by considering the probabilistic characteristics of material and structure parameters. A comprehensive analysis example is carried out at last. The results show that the probability of crack penetrates through wall increases gradually with the growth of fast neutron irradiation flux. The results give advice for reactor life extension.

Keywords: fracture toughness, integrity evaluation, pressurized thermal shock, probabilistic fracture mechanics, reactor pressure vessel

Procedia PDF Downloads 243

Authors: Md Imtiaz, Sanchita Dei, Shubham Damke

Abstract:

In recent years, there has been a rapidly accelerating shift from traditional surface processing operations to subsea processing operation. This shift has been driven by a number of factors including the depletion of shallow fields around the world, technological advances in subsea processing equipment, the need for production from marginal fields, and lower initial upfront investment costs compared to traditional production facilities. Moving production facilities to the seafloor offers a number of advantage, including a reduction in field development costs, increased production rates from subsea wells, reduction in the need for chemical injection, minimization of risks to worker ,reduction in spills due to hurricane damage, and increased in oil production by enabling production from marginal fields. Subsea processing consists of a range of technologies for separation, pumping, compression that enables production from offshore well without the need for surface facilities. At present, there are two primary technologies being used for subsea processing: subsea multiphase pumping and subsea separation. Multiphase pumping is the most basic subsea processing technology. Multiphase pumping involves the use of boosting system to transport the multiphase mixture through pipelines to floating production vessels. The separation system is combined with single phase pumps or water would be removed and either pumped to the surface, re-injected, or discharged to the sea. Subsea processing can allow for an entire topside facility to be decommissioned and the processed fluids to be tied back to a new, more distant, host. This type of application reduces costs and increased both overall facility and integrity and recoverable reserve. In future, full subsea processing could be possible, thereby eliminating the need for surface facilities.

Keywords: FPSO, marginal field, Subsea processing, SWAG

Procedia PDF Downloads 404

Authors: Mohsin Raza, Rizwan Latif, Syed Adnan Qasim, Imran Shafi

Abstract:

High torque low-speed diesel engine has a wide range of industrial and commercial applications. In literature, it’s found that lot of work has been done for the high-speed diesel engine and research on High Torque low-speed is rare. The fuel injection plays a key role in the efficiency of engine and reduction in exhaust emission. The fuel breakup plays a critical role in air-fuel mixture and spray combustion. The current study explains numerically an important phenomenon in spray combustion which is deformation and breakup of liquid drops in compression ignition internal combustion engine. The secondary breakup and its influence on spray and characteristics of compressed gas in-cylinder have been calculated by using simulation software in the backdrop of high torque low-speed diesel like conditions. The secondary spray breakup is modeled with KH - RT instabilities. The continuous field is described by turbulence model and dynamics of the dispersed droplet is modeled by Lagrangian tracking scheme. The results by using KH - RT model are compared against other default methods in OpenFOAM and published experimental data from research and implemented in CFD (Computational Fluid Dynamics). These numerical simulation, done in OpenFoam and Matlab, results are analyzed for the complete 720- degree 4 stroke engine cycle at a low engine speed, for favorable agreement to be achieved. Results thus obtained will be analyzed for better evaporation in near nozzle region. The proposed analyses will further help in better engine efficiency, low emission and improved fuel economy.

Keywords: diesel fuel, KH-RT, Lagrangian , Open FOAM, secondary breakup

Procedia PDF Downloads 254

Authors: Khimmatali Nomozovich Juraev

Abstract:

Silicon carbide is one of the promising materials with potential applications in electronic devices using high power, high frequency and high electric field. Currently, silicon carbide is used to manufacture high power and frequency diodes, transistors, radiation detectors, light emitting diodes (LEDs) and other functional devices. In this work, the effects of magnetic field on p-n junctions based on 4H-SiC were experimentally studied. As a research material, monocrystalline silicon carbide wafers (Cree Research, Inc., USA) with relatively few growth defects grown by physical vapor transport (PVT) method were used: Nd dislocations 104 cm², Nm micropipes ~ 10–10² cm-², thickness ~ 300-600 μm, surface ~ 0.25 cm², resistivity ~ 3.6–20 Ωcm, the concentration of background impurities Nd − Na ~ (0.5–1.0)×1017cm-³. The initial parameters of the samples were determined on a Hall Effect Measurement System HMS-7000 (Ecopia) measuring device. Diffusing Ni nickel atoms were covered to the silicon surface of silicon carbide in a Universal Vacuum Post device at a vacuum of 10-⁵ -10-⁶ Torr by thermal sputtering and kept at a temperature of 600-650°C for 30 minutes. Then Ni atoms were diffused into the silicon carbide 4H-SiC sample at a temperature of 1150-1300°C by low temperature diffusion method in an air atmosphere, and the effects of the magnetic field on the I-V characteristics of the samples were studied. I-V characteristics of silicon carbide 4H-SiC p-n junction sample were measured in the magnetic field and in the absence of a magnetic field. The measurements were carried out under conditions where the magnitude of the magnetic field induction vector was 0.5 T. In the state, the direction of the current flowing through the diode is perpendicular to the direction of the magnetic field. From the obtained results, it can be seen that the magnetic field significantly affects the I-V characteristics of the p-n junction in the magnetic field when it is measured in the forward direction. Under the influence of the magnetic field, the change of the magnetic resistance of the sample of silicon carbide 4H-SiC p-n junction was determined. It was found that changing the magnetic field poles increases the direct forward current of the p-n junction or decreases it when the field direction changes. These unique electrical properties of the 4H-SiC p-n junction sample of silicon carbide, that is, the change of the sample's electrical properties in a magnetic field, makes it possible to fabricate magnetic field sensing devices based on silicon carbide to use at harsh environments in future. So far, the productions of silicon carbide magnetic detectors are not available in the industry.

Keywords: 4H-SiC, diffusion Ni, effects of magnetic field, I-V characteristics

Procedia PDF Downloads 86

Authors: Alaa E. El-sisi, Sherin Zakaria

Abstract:

Rebamipide is an antiulcer drug with unique properties such as anti-inflammatory action. It induces endogenous prostaglandin e2 (PGE2). PGE2 is considered as a potent physiological suppressor of liver fibrosis. Aim of study: This study investigated the effect of rebamipide on hepatic fibrosis. Material and Method: Hepatic fibrosis was induced by intraperitoneal injections (IP) injection of CCl4 (0.45 mL/kg) in corn oil 1:5 twice a week for 4 weeks. Rats were divided into four groups as follow: Group 1 treated with CCL4 only, group 2 and 3 treated with CCL4 and rebamipide 60 mg/kg/day (group2) or 100 mg/kg/day (group3), and the fourth group was considered as control group and treated with vehicles. ALT, AST, and Bilirubin were assayed in serum. Antioxidant markers such as malondialdhyde (MDA) and superoxide dismutase (SOD) and fibrotic markers such as hyaluronic acid (HA) and procollagen-III (procol-III) were evaluated in liver tissues. IL-10 as well as PGE2 were also assayed in liver tissues. Pathologic changes in the liver were detected by hematoxylin and eosin staining. Collagen precipitation in liver tissues was visualized using masson trichrom stain. Results: Rebamipide inhibit CCL4 induced increase in ALT and AST significantly (p < 0.05). Rebamipide exerted an antioxidant effect as it inhibits CCL4 induced increased MDA level and decreased SOD activity. Fibrotic markers assay revealed that repamipide (60 or 100 mg/kg/day) decreased the level of procol-III and HA compared to CCl4 (p < 0.05). Oral administration of Rebamipide was associated with a significant increase (p < 0.05) of PGE2 and IL-10. Rebamipide especially at the dose of (100 mg/kg/day) restores liver histology structure and abolish collagen precipitation in liver tissues. Conclusion: Rebamipide retards hepatic fibrosis induced by CCL4 may be through the induction of PGE2 level.

Keywords: fibrotic markers, hepatic fibrosis, PGE2, rebamipide

Procedia PDF Downloads 477

Authors: Yasufumi Yoshimoto, Enkhjargal Tserenochir, Eiji Kinoshita, Takeshi Otaka

Abstract:

Next generation bio-alcohols produced from non-food based sources like cellulosic biomass are promising renewable energy sources. The present study investigates engine performance, combustion characteristics, and emissions of a small single cylinder direct injection diesel engine fueled by four kinds of next generation bio-alcohol isomer and diesel fuel blends with a constant blending ratio of 3:7 (mass). The tested bio-alcohol isomers here are n-butanol and iso-butanol (C₄ alcohol), and n-pentanol and iso-pentanol (C₅ alcohol). To obtain simultaneous reductions in NOx and smoke emissions, the experiments employed supercharging combined with EGR (Exhaust Gas Recirculation). The boost pressures were fixed at two conditions, 100 kPa (naturally aspirated operation) and 120 kPa (supercharged operation) provided with a roots blower type supercharger. The EGR rates were varied from 0 to 25% using a cooled EGR technique. The results showed that both with and without supercharging, all the bio-alcohol blended diesel fuels improved the trade-off relation between NOx and smoke emissions at all EGR rates while maintaining good engine performance, when compared with diesel fuel operation. It was also found that regardless of boost pressure and EGR rate, the ignition delays of the tested bio-alcohol isomer blends are in the order of iso-butanol > n-butanol > iso-pentanol > n-pentanol. Overall, it was concluded that, except for the changes in the ignition delays the influence of bio-alcohol isomer blends on the engine performance, combustion characteristics, and emissions are relatively small.

Keywords: alternative fuel, butanol, diesel engine, EGR (Exhaust Gas Recirculation), next generation bio-alcohol isomer blended fuel, pentanol, supercharging

Procedia PDF Downloads 154

Authors: Ji Won Kim, Moo Yeol Lee, Keon Wook Kang

Abstract:

GV-1001, 16 amino acid fragment of human telomerase reverse transcriptase catalytic subunit (hTERT), has been developed as an injectable cancer vaccine for many types of solid tumors showing high-level of telomerase activity. In the present study, we evaluated the anti-cancer effect of GV-1001 on androgen-receptor-positive prostate cancer. Two signaling pathways, Gs-adenylate cyclase-cAMP and Gq-IP3-Ca2+ pathways play a central role in GnRH receptor (GnRHR)-mediated activities. We found that leuprolide acetate (LA) mainly acted on Gq-mediated Ca2+ signaling, while GV-1001 preferentially acted on cAMP signaling; and both the effects were counteracted by cetrorelix, a GnRHR antagonist. We further tested whether GV-1001 affects tumor growth of human prostate cancer cells in vivo. Prostate tumor xenografts were established using LNCap, androgen receptor-positive prostate cancer cells, and the nude mice bearing tumors were subcutaneously injected with GV-1001 (0.01, 0.1, 1, 10 microg/kg/day) and LA (0.01 microg/kg/day) for 2 weeks. GV-1001 (1 and 10 microg/kg/day) significantly inhibited tumor growth of LNCap xenografts. Interestingly, mRNA expression of MMP2 and MMP9 was significantly suppressed by GV-1001 injection, but not by LA administration. Boyden chamber assay revealed that GV-1001 potently inhibited cell migration of LNCap. Our finding suggests that GV-1001 as a novel GnRHR ligand, has anti-proliferative and anti-migratory effects on androgen receptor-positive prostate cancer cells.

Keywords: GV-1001, GnRH, hTERT, prostate cancer

Procedia PDF Downloads 355

Authors: Rotimi Larayetana, Yahaya Abdulrazaq, Oladunni O. Falola, Abayomi Ajayi

Abstract:

The aim of this study was to perform green synthesis of silver nanoparticles (AgNPs) with the aqueous extract of Moringa oleifera Lam (M oleifera) leaves and determine its effects on benign prostatic hyperplasia in Wistar rats. Silver nitrate (AgNO₃) solution was reduced using the aqueous extract of Moringa oleifera Lam leaves, the resultant biogenic AgNPs were characterized by Fourier transformed infrared spectrophotometric, SEM, TEM and X-ray diffraction analysis. Animal experiments involved thirty (30) adult male Wistar rats randomly divided into five groups (A to E; n ₌ 5). Group A received only subcutaneous injection of olive oil daily while the other groups got 3 mg/kg/daily of testosterone propionate (TP) subcutaneously plus 50 mg/kg/daily of AgNPs intraperitoneally (B), 3 mg/kg/daily of TP plus 25 mg/kg/daily of AgNPs (C), 3 mg/kg/daily of TP only (D) and 25 mg/kg/daily of AgNPs only (E). The animals were sacrificed after 14 days, and the prostate gland, liver, and kidney were processed for histological analysis. Phytochemical screening and GC-MS analysis were performed to determine the composition of the M oleifera extract used. Biogenic AgNPs with an average diameter of 23 nm were synthesized. Biogenic AgNPs ameliorated hormone-induced prostate enlargement, and the inhibition of prostatic hypertrophy could be due to the presence of a significant amount of plant fatty acids and phytosterols in the aqueous extract of M oleifera extract. However, the administration of biogenic AgNPs at higher doses impacted negatively on the cytoarchitecture of the liver. Green synthesis of AgNPs with the aqueous extract of Moringa oleifera might be beneficial for the treatment of BPH.

Keywords: benign prostatic hyperplasia, biogenic synthesis, Moringa oleifera, silver nanoparticles, testosterone

Procedia PDF Downloads 76

Authors: Jun Yang, Ching-Liang Hsieh, Yi-Wen Lin

Abstract:

Chronic inflammatory pain results from peripheral tissue injury or local inflammation to increase the release of protons, histamines, adenosine triphosphate, and several proinflammatory cytokines. Transient receptor potential vanilloid 1 (TRPV1) is involved in fibromyalgia, neuropathic, and inflammatory pain; however, its exact mechanisms in chronic inflammatory pain are still unclear. We investigate the analgesic effect of EA by injecting complete Freund’s adjuvant (CFA) in the hind paw of mice to induce chronic inflammatory pain ( > 14 d). Our results showed that EA significantly reduced chronic mechanical and thermal hyperalgesia in the chronic inflammatory pain model. Chronic mechanical and thermal hyperalgesia was also abolished in TRPV1−/− mice. TRPV1 increased in the dorsal root ganglion (DRG) and spinal cord (SC) at 2 weeks after CFA injection. The expression levels of downstream molecules such as pPKA, pPI3K, and pPKC increased, as did those of pERK, pp38, and pJNK. Transcription factors (pCREB and pNFκB) and nociceptive ion channels (Nav1.7 and Nav1.8) were involved in this process. Inflammatory mediators such as GFAP (Glial fibrillary acidic protein), S100B, and RAGE (Receptor for advanced glycation endproducts) were also involved. The expression levels of these molecules were reduced in EA (electroacupuncture) and TRPV1−/−mice but not in the sham EA group. The present study demonstrated that EA or TRPV1 gene deletion reduced chronic inflammatory pain through TRPV1 and related molecules. In addition, our data provided evidence to support the clinical use of EA for treating chronic inflammatory pain.

Keywords: auricular electric-stimulation, epileptic seizures, anti-inflammation, electroacupuncture

Procedia PDF Downloads 162

Authors: Bharat Kumar, Deepak Kumar, Vijay Chaudhry

Abstract:

Zirconium alloys are used as core components of nuclear reactors due to their high wear resistance, good corrosion properties, and good mechanical stability at high temperatures. The present work simulates the contact between the calandria tube and the liquid injection shutdown system (LISS) nozzle. The Calandria tube is the outer covering of the pressure tube. Water flows inside the pressure tube through fuel claddings which produces vibration in the pressure tube along with vibration in the calandria tube. Fretting wear takes place at the point of contact between the calandria tube and the LISS nozzle. Fretting tests were performed under different conditions, such as; varying fretting duration (i.e., 1 to 4 hours), varying frequency (i.e., 5 to 6.5 Hz), and varying amplitude (100 to 400 µm). The formation of the oxide layer was observed during the fretting wear test; as a result, the worn product. The worn surfaces were analyzed with scanning electron microscopy (SEM) to analyze the wear mechanism involved in the fretting test, and Energy dispersive x-ray spectroscopy (EDS) and Raman spectroscopy were used to confirm the presence of an oxide layer on the worn surface. The oxide layer becomes more uniform with fretting duration in case of water submerged condition as compared to dry contact condition. The oxide layer is deeply removed at high amplitude due to the change of wear mechanism from adhesion to abrasion, as confirmed by the presence of micro ploughing and micro cutting. Low amplitude fretting favors the formation of the tribo-oxide layer.

Keywords: tribo-oxide layer, wear, mechanically mixed layer, zircaloy

Procedia PDF Downloads 68

Authors: Bartlomiej S. Witkowski, Lukasz Wachnicki, Sylwia Gieraltowska, Rafal Pietruszka, Marek Godlewski

Abstract:

Zinc oxide is extensively studied II-VI semiconductor with a direct energy gap of about 3.37 eV at room temperature and high transparency in visible light spectral region. Due to these properties, ZnO is an attractive material for applications in photovoltaic, electronic and optoelectronic devices. ZnO nanorods, due to a well-developed surface, have potential of applications in sensor technology and photovoltaics. In this work we present a new inexpensive method of the ultra-fast growth of ZnO nanorods from the aqueous solution. This environment friendly and fully reproducible method allows growth of nanorods in few minutes time on various substrates, without any catalyst or complexing agent. Growth temperature does not exceed 50ºC and growth can be performed at atmospheric pressure. The method is characterized by simplicity and allows regulation of size of the ZnO nanorods in a large extent. Moreover the method is also very safe, it requires organic, non-toxic and low-price precursors. The growth can be performed on almost any type of substrate through the homo-nucleation as well as hetero-nucleation. Moreover, received nanorods are characterized by a very high quality - they are monocrystalline as confirmed by XRD and transmission electron microscopy. Importantly oxygen vacancies are not found in the photoluminescence measurements. First results for obtained by us ZnO nanorods in sensor applications are very promising. Resistance UV sensor, based on ZnO nanorods grown on a quartz substrates shows high sensitivity of 20 mW/m2 (2 μW/cm2) for point contacts, especially that the results are obtained for the nanorods array, not for a single nanorod. UV light (below 400 nm of wavelength) generates electron-hole pairs, which results in a removal from the surfaces of the water vapor and hydroxyl groups. This reduces the depletion layer in nanorods, and thus lowers the resistance of the structure. The so-obtained sensor works at room temperature and does not need the annealing to reset to initial state. Details of the technology and the first sensors results will be presented. The obtained ZnO nanorods are also applied in simple-architecture photovoltaic cells (efficiency over 12%) in conjunction with low-price Si substrates and high-sensitive photoresistors. Details informations about technology and applications will be presented.

Keywords: hydrothermal method, photoresistor, photovoltaic cells, ZnO nanorods

Procedia PDF Downloads 427

Authors: Haolun Sun, Ping Wang, Mei Wu, Meng Zhang, Bin Hou, Ling Yang, Xiaohua Ma, Yue Hao

Abstract:

Gallium nitride (GaN) is an attractive material for next-generation power devices. It is noted that the performance of GaN-based high electron mobility transistors (HEMTs) is always limited by the self-heating effect. In response to the problem, integrating devices with polycrystalline diamond (PCD) has been demonstrated to be an efficient way to alleviate the self-heating issue of the GaN-based HEMTs. Among all the heat-spreading schemes, using PCD to cap the epitaxial layer before the HEMTs process is one of the most effective schemes. Now, the mainstream method of fabricating the PCD-capped HEMTs is to deposit the diamond heat-spreading layer on the AlGaN surface, which is covered by a thin nucleation dielectric/passivation layer. To achieve the pattern etching of the diamond heat spreader and device preparation, we selected SiN as the hard mask for diamond etching, which was deposited by plasma-enhanced chemical vapor deposition (PECVD). The conventional diamond etching method first uses F-based etching to remove the SiN from the special window region, followed by using O₂/Ar plasma to etch the diamond. However, the results of the scanning electron microscope (SEM) and focused ion beam microscopy (FIB) show that there are lots of diamond pillars on the etched diamond surface. Through our study, we found that it was caused by the high roughness of the diamond surface and the existence of the overlap between the diamond grains, which makes the etching of the SiN hard mask insufficient and leaves micro-masks on the diamond surface. Thus, a cyclic etching method was proposed to solve the problem of the residual SiN, which was left in the F-based etching. We used F-based etching during the first step to remove the SiN hard mask in the specific region; then, the O₂/Ar plasma was introduced to etch the diamond in the corresponding region. These two etching steps were set as one cycle. After the first cycle, we further used cyclic etching to clear the pillars, in which the F-based etching was used to remove the residual SiN, and then the O₂/Ar plasma was used to etch the diamond. Whether to take the next cyclic etching depends on whether there are still SiN micro-masks left. By using this method, we eventually achieved the self-terminated etching of the diamond and the smooth surface after the etching. These results demonstrate that the cyclic etching method can be successfully applied to the integrated preparation of polycrystalline diamond thin films and GaN HEMTs.

Keywords: AlGaN/GaN heterojunction, O₂/Ar plasma, cyclic etching, polycrystalline diamond

Procedia PDF Downloads 109

Authors: Hager Elsheikh, Matthias Sendler, Juliana Glaubnitz

Abstract:

In pancreatitis, an inflammatory reaction occurs in the pancreatic secretory cells due to premature activation of proteases, leading to pancreatic self-digestion and necrotic cell death of acinar cells. Acute pancreatitis in patients is characterized by a severe immune reaction that could lead to serious complications, such as organ failure or septic shock, if left untreated. Chronic pancreatitis is a recurrence of episodes of acute pancreatitis resulting in a fibro-inflammatory immune response, in which the type 2 immune response is primarily driven by AAMs in the pancreas. One of the most important signaling pathways for M2 macrophage activation is the IL-4/STAT6 pathway. Pancreatic fibrosis is induced by the hyperactivation of pancreatic stellate cells by dysregulation in the inflammatory response, leading to further damage, autodigestion and possibly necrosis of pancreatic acinar cells. The aim of this research is to investigate the effect of STAT6 knockout in disease severity and development of fibrosis wound healing in the presence of different macrophage populations, regulated by the type 2 immune response, after inducing chronic and/or acute pancreatitis in mice models via cerulean injection. We further investigate the influence of the JAK/STAT6 signaling pathway on the balance of fibrosis and regeneration in STAT6 deficient and wild-type mice. The characterization of resident and recruited macrophages will provide insight into the influence of the JAK/STAT6 signaling pathway on infiltrating cells and, ultimately, tissue fibrosis and disease severity.

Keywords: acute and chronic pancreatitis, tissue regeneration, macrophage polarization, Gastroenterology

Procedia PDF Downloads 53

Authors: K. Godazandeh, K. Sadeghy

Abstract:

In the present study, the effect of magnetic field on the hydrodynamic instability of Taylor-Couette flow between two concentric rotating cylinders has been numerically investigated. At the beginning the basic flow has been solved using continuity, Cauchy equations (with regards to Lorentz force) and the constitutive equations of a viscoelastic model called "Giesekus" model. Small perturbations, considered to be normal mode, have been superimposed to the basic flow and the unsteady perturbation equations have been derived consequently. Neglecting non-linear terms, the general eigenvalue problem obtained has been solved using pseudo spectral method (combination of Chebyshev polynomials). The objective of the calculations is to study the effect of magnetic fields on the onset of first mode of instability (axisymmetric mode) for different dimensionless parameters of the flow. The results show that the stability picture is highly influenced by the magnetic field. When magnetic field increases, it first has a destabilization effect which changes to stabilization effect due to more increase of magnetic fields. Therefor there is a critical magnetic number (Hartmann number) for instability of Taylor-Couette flow. Also, the effect of magnetic field is more dominant in large gaps. Also based on the results obtained, magnetic field shows a more considerable effect on the stability at higher Weissenberg numbers (at higher elasticity), while the "mobility factor" changes show no dominant role on the intense of suction and injection effect on the flow's instability.

Keywords: magnetic field, Taylor-Couette flow, Giesekus model, pseudo spectral method, Chebyshev polynomials, Hartmann number, Weissenberg number, mobility factor

Procedia PDF Downloads 381

Authors: Basem Elarbe, Ibrahim Elganidi, Norida Ridzuan, Norhyati Abdullah

Abstract:

Wax deposition in production pipelines and transportation tubing from offshore to onshore is critical in the oil and gas industry due to low-temperature conditions. It may lead to a reduction in production, shut-in, plugging of pipelines and increased fluid viscosity. The most significant popular approach to solve this issue is by injection of a wax inhibitor into the channel. This research aims to determine the amount of wax deposition of Malaysian crude oil by estimating the effective parameters using (Design-Expert version 7.1.6) by response surface methodology (RSM) method. Important parameters affecting wax deposition such as cold finger temperature, inhibitor concentration and experimental duration were investigated. It can be concluded that SA-co-BA copolymer had a higher capability of reducing wax in different conditions where the minimum point of wax reduction was found at 300 rpm, 14℃, 1h, 1200 ppmThe amount of waxes collected for each parameter were 0.12g. RSM approach was applied using rotatable central composite design (CCD) to minimize the wax deposit amount. The regression model’s variance (ANOVA) results revealed that the R2 value of 0.9906, indicating that the model can be clarified 99.06% of the data variation, and just 0.94% of the total variation were not clarified by the model. Therefore, it indicated that the model is extremely significant, confirming a close agreement between the experimental and the predicted values. In addition, the result has shown that the amount of wax deposit decreased significantly with the increase of temperature and the concentration of poly (stearyl acrylate-co-behenyl acrylate) (SABA), which were set at 14°C and 1200 ppm, respectively. The amount of wax deposit was successfully reduced to the minimum value of 0.01 g after the optimization.

Keywords: wax deposition, SABA inhibitor, RSM, operation factors

Procedia PDF Downloads 270