Search results for: unconventional and tight reservoirs

Authors: Ali D. El-mehdawi, Ibrahim E. Elkanouni

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Thick pre-Upper Cretaceous sandstones, sandstones intercalated with red/black shale or quarzitic sandstones, traditionally known to range in age from Cambrian to Early Cretaceous, mostly overlie the subsurface basement rocks of the Sirt Basin of Libya. These sediments known as Nubian, Sarir, Amal or Cambro-Ordovician sandstones. They are usually barren of any age datable palynomorphs and microfossils and represent the main hydrocarbon reservoirs in the basin. As a part of an ongoing regional project concerned with revision and updating of the stratigraphic nomenclature of the Sirt Basin and adjacent areas, sixteen core and ditch cutting samples from four wells penetrating the known Cambro-Ordovician sediments in the central and eastern parts of the basin were examined palynologicaly to investigate its age and the depositional paleoenvironment. The samples proved to be barren or yielded rare palynomorph assemblage, which dominated by dark grey to black small and large-sized sphaeromorph acritarchs assemblage of leiosphaerid types. The dominated species are Kildinosphaera chagrinata, K. cf. chagrinata, Kildinella ripheica, Kilinella timanica, Leiosphaeridia asperata and Leiosphaeridia spp. These leiosphaerides assemblage are comparable to those have been reported from the Late Precambrian, late Riphean age in Cyrenaica Platform, NE Libya, and would indicated shallow marine depositional environment. The age assignment suggests that this interval most probably equates to Mourizide, Bir Bayai and Wadi alHayt formations known in the Murzuq, Kufrah and Cyrenaica areas, respectively. This study proves the presence of Precambrian sediments in Jaghbub high and Amal Platform in the eastern part of Sirt Basin and probably in Maradah Trough and Aj Jahamah/Zoltun Platform northwestern part of the Sirt Basin.

Keywords: palynology, leiosphaerides, precambrian, sirt basin, libya

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Authors: Yu-Yao Wang, Xiao-Meng Hu, Joanne Yeung, Xiao-Yan Li

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The high private cost and unquantified external cost limit the development of reclaimed water. In this study, an integrated framework comprising life cycle assessment (LCA), quantitative microbial risk assessment (QMRA), and life cycle costing (LCC) was developed to evaluate both costs of reclaimed water supply in water systems of various scales. LCA assesses the environmental impacts, and QMRA estimates the associated pathogenic impacts. These impacts are monetized as external costs and analyzed with the private cost by LCC to count the total life cycle cost. The framework evaluated the Hong Kong urban water system in the baseline scenario (BS) and five wastewater reuse scenarios (RS). They are RSI: substituting freshwater for toilet flushing only, RSII: substituting both freshwater and seawater for toilet flushing, RSIII: using reclaimed water for all non-potable uses, RSIV: using reclaimed water for all non-potable uses and indirect potable uses, and RSV: non-potable use and indirect potable use by conveying 100% reclaimed water to recharge the reservoirs. The results show that substituting freshwater and seawater for toilet flushing has the least total life cycle cost, exhibiting that it is the most cost-effective option for Hong Kong. Meanwhile, the evaluation results show that the external cost of each scenario is comparable to the corresponding private cost, indicating the importance of the inclusion of comprehensive external cost evaluation in private cost assessment of water systems with reclaimed water supply.

Keywords: life cycle assessment, life cycle costing, quantitative microbial risk assessment, water reclamation, reclaimed water, alternative water resources

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Authors: Naeimehsadat Hosseininam, Rui Wang, Dishita Shah

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In recent years, new experimental approaches with the help of the new technology have bridged the gaps between the application of natural materials and creating unconventional forms. Clay has been one of the oldest building materials in all ancient civilizations. The availability and workability of clay have contributed to the widespread application of this material around the world. The aim of this experimental research is to apply the Clay 3D printing technology to create a load bearing and visually dynamic and undulating façade. Creation of different unique pieces is the most significant goal of this research which justifies the application of 3D printing technology instead of the conventional mass industrial production. This study provides an abbreviated overview of the similar cases which have used the Clay 3D printing to generate the corresponding prototypes. The study of these cases also helps in understanding the potential and flexibility of the material and 3D printing machine in developing different forms. In the next step, experimental research carried out by 3D printing of six various options which designed considering the properties of clay as well as the methodology of them being 3D printed. Here, the ratio of water to clay (W/C) has a significant role in the consistency of the material and the workability of the clay. Also, the size of the selected nozzle impacts the shape and the smoothness of the final surface. Moreover, the results of these experiments show the limitations of clay toward forming various slopes. The most notable consequence of having steep slopes in the prototype is an unpredicted collapse which is the result of internal tension in the material. From the six initial design ideas, the final prototype selected with the aim of creating a self-supported component with unique blocks that provides a possibility of installing the insulation system within the component. Apart from being an undulated façade, the presented prototype has the potential to be used as a fence and an interior partition (double-sided). The central shaft also provides a space to run services or insulation in different parts of the wall. In parallel to present the capability and potential of the clay 3D printing technology, this study illustrates the limitations of this system in some certain areas. There are inevitable parameters such as printing speed, temperature, drying speed that need to be considered while printing each piece. Clay 3D printing technology provides the opportunity to create variations and design parametric building components with the application of the most practiced material in the world.

Keywords: clay 3D printing, material capability, undulating facade, load bearing facade

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Authors: Renata Szewczyk, Beata Lachtara, Kinga Wieczorek, Jacek Osek

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Campylobacter is recognized as the main cause of bacterial gastrointestinal infections in Europe. A main source of the pathogen is poultry and poultry meat; however, other animals like pigs and cattle can also be reservoirs of the bacteria. Human Campylobacter infections are often self-limiting but in some cases, macrolide and fluoroquinolones have to be used. The aim of this study was to determine antimicrobial resistance patterns (AMR) of Campylobacter isolated from pig and cattle carcasses. Between July 2009 and December 2015, 735 swabs from pig (n = 457) and cattle (n = 278) carcasses were collected at Polish slaughterhouses. All samples were tested for the presence of Campylobacter by ISO 10272-1 and confirmed to species level using PCR. The antimicrobial susceptibility of Campylobacter isolates was determined by a microbroth dilution method with six antimicrobials: gentamicin (GEN), streptomycin (STR), erythromycin (ERY), nalidixic acid (NAL), ciprofloxacin (CIP) and tetracycline (TET). It was found that 167 of 735 samples (22.7%) were contaminated with Campylobacter. The vast majority of them were of pig origin (134; 80.2%), whereas for cattle carcasses Campylobacter was less prevalent (33; 19.8%). Among positive samples C. coli was predominant species (123; 73.7%) and it was isolated mainly from pig carcasses. The remaining isolates were identified as C. jejuni (44; 26.3%). Antimicrobial susceptibility indicated that 22 out of 167 Campylobacter (13.2%) were sensitive to all antimicrobials used. Fourteen of them were C. jejuni (63.6%; pig, n = 6; cattle, n = 8) and 8 was C. coli (36.4%; pig, n = 4; cattle, n = 4). Most of the Campylobacter isolates (145; 86.8%) were resistant to one or more antimicrobials (C. coli, n = 115; C. jejuni, n = 30). Comparing the AMR for Campylobacter species it was found that the most common pattern for C. jejuni was CIP-NAL-TET (9; 30.0%), whereas CIP-NAL-STR-TET was predominant among C. coli (47; 40.9%). Multiresistance, defined as resistance to three or more classes of antimicrobials, was found in 57 C. coli strains, mostly obtained from pig (52 isolates). On the other hand, only one C. jejuni strain, isolated from cattle, showed multiresistance with pattern CIP-NAL-STR-TET. Moreover, CIP-NAL-STR-TET was characteristic for most of multiresistant C. coli isolates (47; 82.5%). For the remaining C. coli the resistance patterns were CIP-ERY-NAL-TET (7 strains; 12.3%) and for one strain of each patterns: ERY-STR-TET, CIP-STR-TET, CIP-NAL-GEN-STR-TET. According to the present findings resistance to erythromycin was observed only in 11 C. coli (pig, n = 10; cattle, n = 1). In conclusion, the results of this study showed that pig carcasses may be a serious public health concern because of contamination with C. coli that might features multiresistance to antimicrobials.

Keywords: antimicrobial resistance, Campylobacter, carcasses, multi resistance

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Authors: Jianzhou Ni, Hua Fan

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It has been determined that supervisor support has a major influence on postgraduate students' academic emotions and is considered a method of successfully anticipating postgraduates' good psychological well-being levels. As a result, by assessing the mediating influence upon academic emotions for contemporary postgraduates in China, this study investigated the tight reciprocal relationship between psychological empowerment and positive mental well-being among postgraduates. To that end, a help enables a theoretical analysis of role clarity, academic emotion, and positive psychological health was developed, and its validity and reliability were demonstrated for the first time using the normalized postgrad relationship with supervisor scale, academic emotion scale, and positive mental scale, as well as questionnaire data from Chinese postgraduate students. This study used the cross-lagged (ARCL) panel model data to longitudinally measure 798 valid data from two survey questions polls taken in 2019 (T1) and 2021 (T2) to investigate the link between supervisor support and positive graduate student mental well-being in a bidirectional relationship of influence. The study discovered that mentor assistance could have a considerable beneficial impact on graduate students' academic emotions and, as a result, indirectly help learners attain positive mental health development. This verifies the theoretical premise that academic emotions partially mediate the effect of mentor support on positive mental health development and argues for the coexistence of the two. The outcomes of this study can help researchers gain a better knowledge of the dynamic interplay among three different research variables: supervisor support, academic emotions, and positive mental health, as well as fill gaps in previous research. In this regard, the study indicated that mentor assistance directly stimulates students' academic drive and assists graduate students in developing good academic emotions, which contributes to the development of positive mental health. However, given the restricted measurement time in this study's cross-lagged panel data and the potential effect of moderating effects other than academic mood on graduate students' good mental health, the results of this study need to be more fully understood and validated.

Keywords: supervisor support, academic emotions, positive mental health, interaction effects, longitudinal cross-lagged measurements

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Authors: Yu-Che Cheng, Min-Lih Chang, Ke-Hao Cheng, Chuan-Cheng Wang

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Taiwan is an island located along the southeastern coast of the Asian continent, located between Japan and the Philippines. It is surrounded by the sea on all sides. However, due to the presence of the Central Mountain Range, the rivers on the east and west coasts of Taiwan are relatively short. This geographical feature results in a phenomenon where, despite having rainfall that is 2.6 times the world average, 58.5% of the rainwater flows into the ocean. Moreover, approximately 80% of the annual rainfall occurs between May and October, leading to distinct wet and dry periods. To address these challenges, Taiwan relies on large reservoirs, storage ponds, and groundwater extraction for water resource allocation. It is necessary to construct water treatment facilities at suitable locations to provide the population with a stable and reliable water supply. In general, the construction of a new water treatment plant requires careful planning and evaluation. The process involves acquiring land and issuing contracts for construction in a sequential manner. With the increasing severity of global warming and climate change, there is a heightened risk of extreme hydrological events and severe water situations in the future. In cases of urgent water supply needs in a region, relying on traditional lengthy processes for constructing water treatment plants might not be sufficient to meet the urgent demand. Therefore, this study aims to explore the use of simplified water treatment procedures and the construction of rapid "temporary water treatment plants" to tackle the challenges posed by extreme climate conditions (such as a century-long drought) and situations where water treatment plant construction cannot keep up with the pace of water source development.

Keywords: temporary water treatment plant, emergency water supply, construction site groundwater, drought

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Authors: Lei Zhao, Yi Song, Tim Dunne, Jiaxiang (Jason) Ren, Wenhan Yue, Lei Yang, Li Wen, Yu Liu

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Fasting dissolving magnesium (DM) alloy technology has contributed significantly to the “Shale Revolution” in oil and gas industry. This application requires DM downhole tools dissolving initially at a slow rate, rapidly accelerating to a high rate after certain period of operation time (typically 8 h to 2 days), a contradicting requirement that can hardly be addressed by traditional Mg alloying or processing itself. Premature disintegration has been broadly reported in downhole DM tool from field trials. To address this issue, “temporary” thin polymers of various formulations are currently coated onto DM surface to delay its initial dissolving. Due to conveying parts, harsh downhole condition, and high dissolving rate of the base material, the current delay coatings relying on pure polymers are found to perform well only at low temperature (typical < 100 ℃) and parts without sharp edges or corners, as severe geometries prevent high quality thin film coatings from forming effectively. In this study, a coating technology combining Plasma Electrolytic Oxide (PEO) coatings with advanced thin film deposition has been developed, which can delay DM complex parts (with sharp corners) in corrosive fluid at 150 ℃ for over 2 days. Synergistic effects between porous hard PEO coating and chemical inert elastic-polymer sealing leads to its delaying dissolution improvement, and strong chemical/physical bonding between these two layers has been found to play essential role. Microstructure of this advanced coating and compatibility between PEO and various polymer selections has been thoroughly investigated and a model is also proposed to explain its delaying performance. This study could not only benefit oil and gas industry to unplug their High Temperature High Pressure (HTHP) unconventional resources inaccessible before, but also potentially provides a technical route for other industries (e.g., bio-medical, automobile, aerospace) where primer anti-corrosive protection on light Mg alloy is highly demanded.

Keywords: dissolvable magnesium, coating, plasma electrolytic oxide, sealer

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Authors: Morteza Taherinezhad, Ahmad Reza Rabbani, Morteza Asemani, Rudy Swennen

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Oil-oil correlation is one of the most important issues in geochemical studies that enables to classify oils genetically. Oil-oil correlation is generally estimated based on non-polar fractions of crude oil (e.g., saturate and aromatic compounds). Despite several advantages, the drawback of using these compounds is their susceptibility of being affected by secondary processes. The polar fraction of crude oil (e.g., asphaltenes) has similar characteristics to kerogen, and this structural similarity is preserved during migration, thermal maturation, biodegradation, and water washing. Therefore, these structural characteristics can be considered as a useful correlation parameter, and it can be concluded that asphaltenes from different reservoirs with the same genetic signatures have a similar origin. Hence in this contribution, an integrated study by using both non-polar and polar fractions of oil was performed to use the merits of both fractions. Therefore, five oil samples from oil fields in the Persian Gulf were studied. Structural characteristics of extracted asphaltenes were investigated by Fourier transform infrared (FTIR) spectroscopy. Graphs based on aliphatic and aromatic compounds (predominant compounds in asphaltenes structure) and sulphoxide and carbonyl functional groups (which are representatives of sulphur and oxygen abundance in asphaltenes) were used for comparison of asphaltenes structures in different samples. Non-polar fractions were analyzed by GC-MS. The study of asphaltenes showed the studied oil samples comprise two oil families with distinct genetic characteristics. The first oil family consists of Salman and Reshadat oil samples, and the second oil family consists of Resalat, Siri E, and Siri D oil samples. To validate our results, biomarker parameters were employed, and this approach completely confirmed previous results. Based on biomarker analyses, both oil families have a marine source rock, whereby marl and carbonate source rocks are the source rock for the first and the second oil family, respectively.

Keywords: biomarker, non-polar fraction, oil-oil correlation, petroleum geochemistry, polar fraction

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Authors: Vinda B. Manurung, Laila Warkhaida, David Hutabarat, Sentanu Wisnuwardhana, Christovik Simatupang, Dhani Sanjaya, Ashadi, Redha B. Putra, Kiki Yustendi

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The geothermal drilling environment presents many obstacles that have limited the use of directional drilling and logging-while-drilling (LWD) technologies, such as borehole washout, mud losses, severe vibration, and high temperature. The case study presented in this paper demonstrates a practice to enhance data logging in geothermal drilling by deploying advanced telemetry and LWD technologies. This operation is aiming continuous improvement in geothermal drilling operations. The case study covers a 12.25-in. hole section of well XX-05 in Pad XX of the Sorik Marapi Geothermal Field. LWD string consists of electromagnetic (EM) telemetry, pressure while drilling (PWD), vibration (DDSr), and acoustic calliper (ACAL). Through this tool configuration, the operator acquired drilling mechanics and caliper logs in real-time and recorded mode, enabling effective monitoring of wellbore stability. Throughout the real-time acquisition, EM-PPM telemetry had provided a three times faster data rate to the surface unit. With the integration of Caliper data and Drilling mechanics data (vibration and ECD -equivalent circulating density), the borehole conditions were more visible to the directional driller, allowing for better control of drilling parameters to minimize vibration and achieve optimum hole cleaning in washed-out or tight formation sequences. After reaching well TD, the recorded data from the caliper sensor indicated an average of 8.6% washout for the entire 12.25-in. interval. Washout intervals were compared with loss occurrence, showing potential for the caliper to be used as an indirect indicator of fractured intervals and validating fault trend prognosis. This LWD case study has given added value in geothermal borehole characterization for both drilling operation and subsurface. Identified challenges while running LWD in this geothermal environment need to be addressed for future improvements, such as the effect of tool eccentricity and the impact of vibration. A perusal of both real-time and recorded drilling mechanics and caliper data has opened various possibilities for maximizing sensor usage in future wells.

Keywords: geothermal drilling, geothermal formation, geothermal technologies, logging-while-drilling, vibration, caliper, case study

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Authors: Denise Bianco

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Several studies on innovation and creativity in organisations emphasise the need to expand horizons and take on alternative and unexpected views to produce something new. This paper theorises the potential impact artists can have as creative catalysts, working embedded in non-artistic organisations. It begins from an understanding that in today's ever-changing scenario, organisations are increasingly seeking to open up new creative thinking through deviant behaviours to produce innovation and that art residencies need to be critically revised in this specific context in light of their disruptive potential. On the one hand, this paper builds upon recent contributions made on workplace creativity and related concepts of deviance and disruption. Research suggests that creativity is likely to be lower in work contexts where utter conformity is a cardinal value and higher in work contexts that show some tolerance for uncertainty and deviance. On the other hand, this paper draws attention to Artist-in-Residence as a vehicle for epistemic friction between divergent and convergent thinking, which allows the creation of unparalleled ways of knowing in the dailiness of situated and contextualised social processes. In order to do so, this contribution brings together insights from the most relevant theories on organisational creativity and unconventional agile methods such as Art Thinking and direct insights from ethnographic fieldwork in the context of embedded art residencies within work organisations to propose a redefinition of Artist-in-Residence and their potential impact on organisational creativity. The result is a re-definition of embedded Artist-in-Residence in organisational settings from a more comprehensive, multi-disciplinary, and relational perspective that builds on three focal points. First the notion that organisational creativity is a dynamic and synergistic process throughout which an idea is framed by recurrent activities subjected to multiple influences. Second, the definition of embedded Artist-in-Residence as an assemblage of dynamic, productive relations and unexpected possibilities for new networks of relationality that encourage the recombination of knowledge. Third, and most importantly, the acknowledgment that embedded residencies are, at the very essence, bi-cultural knowledge contexts where creativity flourishes as the result of open-to-change processes that are highly relational, constantly negotiated, and contextualised in time and space.

Keywords: artist-in-residence, convergent and divergent thinking, creativity, creative friction, deviance and creativity

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Authors: Chukwuka Justus Iwegbu, Monye Christopher Prayer

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Propeller aircraft engines, and more generally engines with a large rotating part (turboprops, high bypass ratio turbojets, etc.) are widely used in the industry and are subject to numerous developments in order to reduce their fuel consumption. In this context, unconventional architectures such as open rotors or distributed propulsion appear, and it is necessary to consider the influence of these systems on the aircraft's stability in flight. Indeed, the tendency to lengthen the blades and wings on which these propulsion devices are fixed increases their flexibility and accentuates the risk of whirl flutter. This phenomenon of aeroelastic instability is due to the precession movement of the axis of rotation of the propeller, which changes the angle of attack of the flow on the blades and creates unsteady aerodynamic forces and moments that can amplify the motion and make it unstable. The whirl flutter instability can ultimately lead to the destruction of the engine. We note the existence of a critical speed of the incident flow. If the flow velocity is lower than this value, the motion is damped and the system is stable, whereas beyond this value, the flow provides energy to the system (negative damping) and the motion becomes unstable. A simple model of whirl flutter is based on the work of Houbolt & Reed who proposed an analytical expression of the aerodynamic load on a rigid blade propeller whose axis orientation suffers small perturbations. Their work considered a propeller subjected to pitch and yaw movements, a flow undisturbed by the blades and a propeller not generating any thrust in the absence of precession. The unsteady aerodynamic forces were then obtained using the thin airfoil theory and the strip theory. In the present study, the unsteady aerodynamic loads are expressed for a general movement of the propeller (not only pitch and yaw). The acceleration and rotation of the flow by the propeller are modeled using a Blade Element Momentum Theory (BEMT) approach, which also enable to take into account the thrust generated by the blades. It appears that the thrust has a stabilizing effect. The aerodynamic model is further developed using Theodorsen theory. A reduced order model of the aerodynamic load is finally constructed in order to perform linear stability analysis.

Keywords: advancing, entrepreneurial, knowledge, industralization

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Authors: Ghadeer Aly, Yasmeen Hanafy

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The way we research travel options and decide where to go has substantially changed in the digital age. Atypical search engines like social networking sites like TikTok have evolved, influencing the preferences of various generations. The influence of TikTok use as a search engine for choosing travel locations and its effect on a country's destination branding are both examined in this study. The study specifically focuses on the comparative preferences and actions of Generations Y and Z within the Egyptian community, shedding light on how these generations interact with travel related TikTok content and how it influences their perceptions of various destinations. It also investigates how TikTok Accounts use tourism branding techniques to promote a country's tourist destination. The investigation of how social media platforms are changing as unconventional search engines has theoretical relevance. This study can advance our knowledge of how digital platforms alter information-seeking behaviors and affect the way people make decisions. Furthermore, investigating the relationship between TikTok video and destination branding might shed light on the intricate interplay between social media, perceptions of locations, and travel preferences, enhancing theories about consumer behavior and communication in the digital age. Regarding the methodology of the research, the study is conducted in two stages: first, both generations are polled, and from the results, the top three destinations are chosen to be subjected to content analysis. As for the research's theoretical framework, it incorporates the tourism destination branding model as well as the conceptual model of nation branding. Through the use of the survey as a quantitative approach and the qualitative content analysis, the research will rely on both quantitative and qualitative methods. When it comes to the theoretical framework, both the Nation Branding Model and the Tourism Branding Model can offer useful frameworks for analyzing and comprehending the dynamics of using TikTok as a search engine to choose travel destinations, especially in the context of Generation Y and Generation Z in the Egyptian community. Additionally, the sample will be drawn specifically from both Gen-Y and Gen-Z. 100 members of Gen Z and 100 members of Gen Y will be chosen from TikTok users and followers of travel-related accounts, and the sample for the content analysis will be chosen based on the survey's results.

Keywords: tiktok, nation image, egyptian community, tourism branding

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Authors: I. Farid, K. Zouari

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An attempt has been made to examine the effect of water storage structures on groundwater recharge in a semi-arid agroclimatic setting in Jeloula Basin (Central Tunisia). In this area, surface water in rivers is seasonal, and therefore groundwater is the perennial source of water supply for domestic and agricultural purposes. Three pumped storage water power plants (PSWPP) have been built to increase the overall water availability in the basin and support agricultural livelihoods of rural smallholders. The scale and geographical dispersion of these multiple lakes restrict the understanding of these coupled human-water systems and the identification of adequate strategies to support riparian farmers. In the present review, hydrochemistry and isotopic tools were combined to get an insight into the processes controlling mineralization and recharge conditions in the investigated aquifer system. This study showed a slight increase in the groundwater level, especially after the artificial recharge operations and a decline when the water volume moves down during drought periods. Chemical data indicate that the main sources of salinity in the waters are related to water-rock interactions. Data inferred from stable isotopes in groundwater samples indicated recharge with modern rainfall. The investigated surface water samples collected from the PSWPP are affected by a significant evaporation and reveal large seasonal variations, which could be controlled by the water volume changes in the open surface reservoirs and the meteorological conditions during evaporation, condensation, and precipitation. The geochemical information is comparable to the isotopic results and illustrates that the chemical and isotopic signatures of reservoir waters differ clearly from those of groundwaters. These data confirm that the contribution of the artificial recharge operations from the PSWPP is very limited.

Keywords: Jeloula basin, recharge, hydrochemistry, isotopes

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Authors: Dumont Maxime, Correia Carlos, Sauvage Jean-François, Schwartz Noah, Gray Morgan

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Context: The concept of the segmented telescope is unavoidable to build extremely large telescopes (ELT) in the quest for spatial resolution, but it also allows one to fit a large telescope within a reduced volume of space (JWST) or into an even smaller volume (Standard Cubesat). Cubesats have tight constraints on the computational burden available and the small payload volume allowed. At the same time, they undergo thermal gradients leading to large and evolving optical aberrations. The pupil segmentation comes nevertheless with an obvious difficulty: to co-phase the different segments. The CubeSat constraints prevent the use of a dedicated wavefront sensor (WFS), making the focal-plane images acquired by the science detector the most practical alternative. Yet, one of the challenges for the wavefront sensing is the non-linearity between the image intensity and the phase aberrations. Plus, for Earth observation, the object is unknown and unrepeatable. Recently, several studies have suggested Neural Networks (NN) for wavefront sensing; especially convolutional NN, which are well known for being non-linear and image-friendly problem solvers. Aims: We study in this paper the prospect of using NN to measure the phasing aberrations of a segmented pupil from the focal-plane image directly without a dedicated wavefront sensing. Methods: In our application, we take the case of a deployable telescope fitting in a CubeSat for Earth observations which triples the aperture size (compared to the 10cm CubeSat standard) and therefore triples the angular resolution capacity. In order to reach the diffraction-limited regime in the visible wavelength, typically, a wavefront error below lambda/50 is required. The telescope focal-plane detector, used for imaging, will be used as a wavefront-sensor. In this work, we study a point source, i.e. the Point Spread Function [PSF] of the optical system as an input of a VGG-net neural network, an architecture designed for image regression/classification. Results: This approach shows some promising results (about 2nm RMS, which is sub lambda/50 of residual WFE with 40-100nm RMS of input WFE) using a relatively fast computational time less than 30 ms which translates a small computation burder. These results allow one further study for higher aberrations and noise.

Keywords: wavefront sensing, deep learning, deployable telescope, space telescope

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Authors: Aishwarya Pothula

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Euthanasia in India is a politically dormant policy issue in the sense that discussions around it are sporadic in nature (usually with developments in specific cases) and it stays as a dominant issue in the public domain for a fleeting period. In other words, it is a non-political issue that has been unable to successfully get on the policy agenda. This paper studies how the Supreme Court of India (SC) plays a role in euthanasia’s policy making. In 2011, the SC independently put a law in place that legalized passive euthanasia through its judgement in the Aruna Shanbaug v. Union of India case. According to this, it is no longer illegal to withhold/withdraw a patient’s medical treatment in certain cases. This judgement, therefore, is the empirical focus of this paper. The paper essentially employs two techniques of discourse analysis to study the SC’s system of argumentation. The two methods, Text Analysis using Gasper’s Analysis Table and Frame Analysis – are complemented by two discourse techniques called metaphor analysis and lexical analysis. The framework within which the analysis is conducted lies in 1) the judicial process of India, i.e. the SC procedures and the Constitutional rules and provisions, and 2) John W. Kingdon’s theory of policy windows and policy entrepreneurs. The results of this paper are three-fold: first, the SC dismiss the petitioner’s request for passive euthanasia on inadequate and weak grounds, thereby setting no precedent for the historic law they put in place. In other words, they leave the decision open for the Parliament to act upon. Hence the judgement, as opposed to arguments by many, is by no means an instance of judicial activism/overreach. Second, they define euthanasia in a way that resonates with existing broader societal themes. They combine this with a remarkable use of authoritative and protective tones/stances to settle at an intermediate position that balances the possible opposition to their role in the process and what they (perhaps) perceive to be an optimal solution. Third, they soften up the policy community (including the public) to the idea of passive euthanasia leading it towards a Parliamentarian legislation. They achieve this by shaping prevalent principles, provisions and worldviews through an astute use of the legal instruments at their disposal. This paper refers to this unconventional role of the SC as ‘judicial entrepreneurship’ which is also the first scholarly contribution towards research on euthanasia as a policy issue in India.

Keywords: argumentation analysis, Aruna Ramachandra Shanbaug, discourse analysis, euthanasia, judicial entrepreneurship, policy-making process, supreme court of India

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Authors: E. N. Masri, E. Takács

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Amplitude Versus Offset (AVO) and simultaneous model-based impedance inversion techniques have not been utilized for geothermal exploration commonly; however, some recent publications called the attention that they can be very useful in the geothermal investigations. In this study, we present rock physical attributes obtained from 3D pre-stack seismic data and well logs collected in a study area of the NW part of Pannonian Basin where the geothermal reservoir is located in the fractured zones of Triassic basement and it was hit by three productive-injection well pairs. The holes were planned very successfully based on the conventional 3D migrated stack volume prior to this study. Subsequently, the available geophysical-geological datasets provided a great opportunity to test modern inversion procedures in the same area. In this presentation, we provide a summary of the theory and application of the most promising seismic inversion techniques from the viewpoint of geothermal exploration. We demonstrate P- and S-wave impedance, as well as the velocity (Vp and Vs), the density, and the Vp/Vs ratio attribute volumes calculated from the seismic and well-logging data sets. After a detailed discussion, we conclude that P-wave impedance and Vp/Vp ratio are the most helpful parameters for lithology discrimination in the study area. They detect the hot water saturated fracture zone very well thus they can be very useful in mapping the investigated reservoir. Integrated interpretation of all the obtained rock-physical parameters is essential. We are extending the above discussed pre-stack seismic tools by studying the possibilities of Elastic Impedance Inversion (EII) for geothermal exploration. That procedure provides two other useful rock-physical properties, the compressibility and the rigidity (Lamé parameters). Results of those newly created elastic parameters will also be demonstrated in the presentation. Geothermal extraction is of great interest nowadays; and we can adopt several methods have been successfully applied in the hydrocarbon exploration for decades to discover new reservoirs and reduce drilling risk and cost.

Keywords: fractured zone, seismic, well-logging, inversion

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Authors: A. Yousuf, M. Iqbal, A. Mir, S. Aziz

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This study deals with the women’s right to land for gender equality. Economic Transformation Initiative, Gilgit-Baltistan (ETI-GB), an ambitious program supported by International Fund for Agricultural Development United Nation (IFAD, UN), aims to strengthen land reforms process in disputed area of Gilgit-Baltistan (GB) Pakistan, that is taking place first time in the history. This project is a brick to build the foundation of land reforms and land policies in GB. The ETI-GB provides substantive support to government of GB in developing policy measures and initiatives to promote women’s right to have and to own land is kind of unconventional step in a very traditional society. It would be interesting to have discussion and document the people’s response regarding this project. The study has used mixed method for data collection. For qualitative data, content analysis is used to have a thorough understanding of different types of land reforms across the globe particularly in South Asia. Theoretical understanding of the literature is essential which provides the basis why land reforms are important and how far it plays an important role when it comes to eliminating inequality. Focused group discussion was carried out for verification and triangulation of data. For quantitative, survey was conducted to take responses from the people of the region and analyzed. The program is implemented in Ghizer district of GB. 2340 households were identified as beneficiaries of newly developed land. Among them, 2285 were men households, and 55 were women households. There is a significant difference between men and women households. In spite of great difference, it is a great achievement of the donor that in history of GB, first time women are going to be entitled to land ownership. GB is a patriarchal society, many social factors like cultural, religious play role for gender inequality. In developing countries, such as Pakistan, the awareness of land property rights has not been given proper attention to gender equality development frameworks. It is argued that land property rights of women have not been taken into mainstream policymaking in the development of nation building process. Consequently, this has generated deprivation of women’s property rights, low income level, lack of education and poor health. This paper emphasises that there should have proper land property right of women in Gilgit-Baltistan Pakistan, provided that the gender empowerment could be increased in terms of women’s property rights.

Keywords: gender equality, women right to land ownership, property rights, women empowerment

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Authors: Ragi Poyyara, Vijaya Patnana, Mohammed Alam

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When acid is pumped into damaged reservoirs for damage removal/stimulation, distorted inflow of acid into the formation occurs caused by acid preferentially traveling into highly permeable regions over low permeable regions, or (in general) into the path of least resistance. This can lead to poor zonal coverage and hence warrants diversion to carry out an effective placement of acid. Diversion is desirably a reversible technique of temporarily reducing the permeability of high perm zones, thereby forcing the acid into lower perm zones. The uniqueness of each reservoir can pose several challenges to engineers attempting to devise optimum and effective diversion strategies. Diversion techniques include mechanical placement and/or chemical diversion of treatment fluids, further sub-classified into ball sealers, bridge plugs, packers, particulate diverters, viscous gels, crosslinked gels, relative permeability modifiers (RPMs), foams, and/or the use of placement techniques, such as coiled tubing (CT) and the maximum pressure difference and injection rate (MAPDIR) methodology. It is not always realized that the effectiveness of diverters greatly depends on reservoir properties, such as formation type, temperature, reservoir permeability, heterogeneity, and physical well characteristics (e.g., completion type, well deviation, length of treatment interval, multiple intervals, etc.). This paper reviews the mechanisms by which each variety of diverter functions and discusses the effect of various reservoir properties on the efficiency of diversion techniques. Guidelines are recommended to help enhance productivity from zones of interest by choosing the best methods of diversion while pumping an optimized amount of treatment fluid. The success of an overall acid treatment often depends on the effectiveness of the diverting agents.

Keywords: diversion, reservoir, zonal coverage, carbonate, sandstone

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Authors: Ali Alahmari

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Saudi Arabia is facing increasing challenges in managing urban drainage, due to a combination of factors including climate change and urban expansion. Traditional drainage systems are unable to cope with demand, resulting in flooding and damage to property. Consequently, new ways of dealing with this issue need to be found and Sustainable Urban Drainage Systems (SUDS) appear to be a possible solution. This paper suggests that knowledge is a central issue in the adoption of Sustainable Urban Drainage approaches, as revealed through qualitative research with representative officials and professionals from key government departments and organisations in Riyadh. Semi-structured interviews were conducted with twenty-six participants. The interviews explored the challenges of adopting sustainable drainage approaches, and grounded theory analysis was used to examine the role of knowledge. However, a number of barriers have been identified with regard to the adoption of sustainable drainage approaches, such as the marginal status of sustainability in drainage decisions; lack of technical standards for other unconventional drainage solutions, and lack of consideration by decision makers of contributions from environmental and geographical studies. Due to centralisation, decision-making processes are complex and time-consuming, resulting in the discouragement of the adoption of new knowledge and approaches. Stakeholders with knowledge of sustainable approaches are often excluded from the hierarchical system of urban planning and drainage management. In addition, the multiplicity of actors involved in the implementation of the drainage system, as well as the different technical standards involved, often causes problems around coordination and cooperation. Although those with procedural and explicit knowledge have revealed a range of opportunities, such as a significant increase in government support for rainwater drainage in urban areas, they also identified a number of obstacles. These are mainly related to the lack of specialists in sustainable approaches, and a reluctance to involve external experts. Therefore, recommendations for overcoming some of these challenges are presented, which include enhancing the decision-making process through applying decentralisation and promoting awareness of sustainability through establishing educational and outreach programmes. This may serve to increase knowledge and facilitate the adoption of sustainable drainage approaches to promote sustainable development in the context of Saudi Arabia.

Keywords: climate change, decision-making processes, new knowledge and approaches, resistance to change, Saudi Arabia, SUDS, urban expansion

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Authors: Kun Hua O., Dong Woon Kim, Won Hyung Lee

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Introduction: Neuropathic pain induced by spinal or peripheral nerve injury is highly resistant to common painkillers, nerve blocks, and other pain management approaches. Recently, several new therapeutic drug candidates have been developed to control neuropathic pain. In this study, we used the spinal nerve L5 ligation (SNL) model to investigate the ability of intrathecal or intravenous Evans blue to decrease pain behavior and to study the relationship between Evans blue and the neural structure of pain transmission. Method: Neuropathic pain (allodynia) of the left hind paw was induced by unilateral SNL in Sprague-Dawley rats(n=10) in each group. Evans blue (5, 15, 50μg/10μl) or phosphate buffer saline(PBS,10μl) was injected intrathecally at 3days post-ligation or intravenously(1mg/200 μl) 3days and 5days post-ligation . Mechanical sensitivity was assessed using Von Frey filaments at 3 days post-ligation and at 2 hours, days 1, 2, 3, 5,7 after intrathecal Evans blue injection, and on days 2, 4, 7, and 11 at 14 days after intravenous injection. In the intrathecal group, microglia and glutaminergic neurons in the dorsal horn and VNUT(vesicular nucleotide transporter) in the dorsal root ganglia were tested to evaluate co-staining with Evans blue. The experimental procedures were performed in accordance with the animal care guideline of the Korean Academy of Medical Science(Animal ethic committee of Chungnam National University Hospital: CNUH-014-A0005-1). Results: Tight ligation of the L5 spinal nerve induced allodynia in the left hind paw 3 days post-ligation. Intrathecal Evans blue most significantly(P＜0.001) alleviated allodynia at 2 days after intrathecal, but not an intravenous injection. Glutaminergic neurons in the dorsal horn and VNUT in the dorsal root ganglia were co-stained with Evans blue. On the other hand, microglia in the dorsal horn were partially co-stained with Evans blue. Conclusion: We confirmed that Evans blue might have an analgesic effect through the central nervous system, not another system in neuropathic pain of the SNL animal model. These results suggest Evans blue may be a potential new drug for the treatment of chronic pain. This research was supported by the National Research Foundation of Korea (NRF-2020R1A2C100757512), funded by the Ministry of Education.

Keywords: neuropathic pain, Evas blue, intrathecal, intravenous

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Authors: Xianwei Zheng, Yuan Yan Tang

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Classical window Fourier transform has been widely used in signal processing, image processing, machine learning and pattern recognition. The related Gabor transform is powerful enough to capture the texture information of any given dataset. Recently, in the emerging field of graph signal processing, researchers devoting themselves to develop a graph signal processing theory to handle the so-called graph signals. Among the new developing theory, windowed graph Fourier transform has been constructed to establish a time-frequency analysis framework of graph signals. The windowed graph Fourier transform is defined by using the translation and modulation operators of graph signals, following the similar calculations in classical windowed Fourier transform. Specifically, the translation and modulation operators of graph signals are defined by using the Laplacian eigenvectors as follows. For a given graph signal, its translation is defined by a similar manner as its definition in classical signal processing. Specifically, the translation operator can be defined by using the Fourier atoms; the graph signal translation is defined similarly by using the Laplacian eigenvectors. The modulation of the graph can also be established by using the Laplacian eigenvectors. The windowed graph Fourier transform based on these two operators has been applied to obtain time-frequency representations of graph signals. Fundamentally, the modulation operator is defined similarly to the classical modulation by multiplying a graph signal with the entries in each Fourier atom. However, a single Laplacian eigenvector entry cannot play a similar role as the Fourier atom. This definition ignored the relationship between the translation and modulation operators. In this paper, a new definition of the modulation operator is proposed and thus another time-frequency framework for graph signal is constructed. Specifically, the relationship between the translation and modulation operations can be established by the Fourier transform. Specifically, for any signal, the Fourier transform of its translation is the modulation of its Fourier transform. Thus, the modulation of any signal can be defined as the inverse Fourier transform of the translation of its Fourier transform. Therefore, similarly, the graph modulation of any graph signal can be defined as the inverse graph Fourier transform of the translation of its graph Fourier. The novel definition of the graph modulation operator established a relationship of the translation and modulation operations. The new modulation operation and the original translation operation are applied to construct a new framework of graph signal time-frequency analysis. Furthermore, a windowed graph Fourier frame theory is developed. Necessary and sufficient conditions for constructing windowed graph Fourier frames, tight frames and dual frames are presented in this paper. The novel graph signal time-frequency analysis framework is applied to signals defined on well-known graphs, e.g. Minnesota road graph and random graphs. Experimental results show that the novel framework captures new features of graph signals.

Keywords: graph signals, windowed graph Fourier transform, windowed graph Fourier frames, vertex frequency analysis

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Authors: Irena Baranowska-Bosiacka, Mateusz Bosiacki, Patrycja Kupnicka, Anna Lubkowska, Dariusz Chlubek

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Physical activity and a balanced diet are among the key factors of "healthy ageing". Physical effort, including swimming in cold water (including bathing in natural water reservoirs), is widely recognized as a hardening factor, with a positive effect on the mental and physical health. At the same time, there is little scientific evidence to verify this hypothesis. In the literature to date, it is possible to obtain data on the impact of these factors on selected physiological and biochemical parameters of the blood, at the same time there are no results of research on the effect of immersing in cold water on mineral metabolism, especially bones, hence it seems important to perform such an analysis in relation to the key elements such as calcium (Ca), magnesium (Mg) and phosphorus (P). Taking the above into account, a hypothesis was put forward about the possibility of a positive effect of exercise in cold water on mineral metabolism and bone density in aging rats. The aim of the study was to evaluate the effect of an 8-week swimming training on mineral metabolism and bone density in aging rats in response to exercise in cold water (5oC) in comparison to swimming in thermal comfort (36oC) and sedentary (control) rats of both sexes. The examination of the concentration of the examined elements in the bones was carried out using inductively coupled plasma atomic emission spectrometry (ICP-OES). The mineral density of the femurs of the rats was measured using the Hologic Horizon DEXA System® densitometer. The results of our study showed that swimming in cold water affects bone mineral metabolism in aging rats by changing the Ca, Mg, P concentration and at the same time increasing their bone density. In males, a decrease in Mg concentration and no changes in bone density were observed. In the light of the research results, it seems that swimming in cold water may be a factor that positively modifies the bone aging process by improving the mechanisms affecting their density.

Keywords: swimming in cold water, adaptation to cold water, bone mineral metabolism, aging

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Authors: Camila Lozano-Vivas, Camila Quevedo-Villamil, Ingrid Munoz-Quijano, Diego Loaiza

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Colombia's limited oil reserves make the finding of new fields of extraction or the potentiate of the existing ones a more important task to do every day; the exploration projects that allow to have a better knowledge of the oil basins are essential. The upper Magdalena Valley basin - VSM, whose reserves are limited, has been one of the first basins for the exploration and production of hydrocarbons in Colombia. The Hondita and Lomagorda formations were deposited in the Late Cretaceous Middle Albian to the Coniacian and are characterized by being the hydrocarbon-generating rocks in the VSM basin oil system along with the Shale de Bambucá; therefore multiple studies have been made. In the oil industry, geochemical properties are used to understand the origin, migration, accumulation, and alteration of hydrocarbons and, in general, the evolution of the basin containing them. One of the most important parameters to understand this evolution is the formation temperature of the oil system. For this reason, a microthermometric study of fluid inclusions was carried out to recognize formation temperatures and to determine certain basic physicochemical variables, homogenization temperature, pressure, density and salinity of the fluid at the time of entrapment, providing evidence on the history of different events in different geological environments in the evolution of a sedimentary basin. Prior to this study, macroscopic and microscopic petrographic analyses of the samples collected in the field were performed. The results of the mentioned properties of the fluid inclusions in the different samples analyzed have salinities ranging from 20.22% to 26.37% eq. by weight NaCl, similar densities found in the ranges of 1.05 to 1.16 g/cc and an average homogenization temperature at 142.92°C, indicating that, at the time of their entanglement, the rock was in the window of generation of medium hydrocarbons –light with fragile characteristics of the rock that would make it useful to treat them as naturally fractured reservoirs.

Keywords: homogenization temperature, fluid inclusions, microthermometry, salinity

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Authors: Sonia Barbouchi, Meriem Samcha

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Scale deposition during water injection into aquifer of oil reservoirs is a serious problem experienced in the oil production industry. One of the primary causes of scale formation and injection well plugging is mixing two waters which are incompatible. Considered individually, the waters may be quite stable at system conditions and present no scale problems. However, once they are mixed, reactions between ions dissolved in the individual waters may form insoluble products. The purpose of this study is to identify the causes of well plugging in a southern Tunisian oilfield, where fresh water has been injected into the producing wells to counteract the salinity of the formation waters and inhibit the deposition of halite. X-ray diffraction (XRD) mineralogical analysis has been carried out on scale samples collected from the blocked well. Two samples collected from both formation water and injected water were analysed using inductively coupled plasma atomic emission spectroscopy, ion chromatography and other standard laboratory techniques. The results of complete waters analysis were the typical input parameters, to determine scaling tendency. Saturation indices values related to CaCO3, CaSO4, BaSO4 and SrSO4 scales were calculated for the water mixtures at different share, under various conditions of temperature, using a computerized scale prediction model. The compatibility study results showed that mixing the two waters tends to increase the probability of barite deposition. XRD analysis confirmed the compatibility study results, since it proved that the analysed deposits consisted predominantly of barite with minor galena. At the studied temperatures conditions, the tendency for barite scale is significantly increasing with the increase of fresh water share in the mixture. The future scale inhibition and removal strategies to be implemented in the concerned oilfield are being derived in a large part from the results of the present study.

Keywords: compatibility study, produced water, scaling, water injection

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Authors: Ali Alahmari

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Urban drainage in Saudi Arabia is an increasingly challenging issue due to factors such as climate change and rapid urban expansion. The existing infrastructure, based on traditional drainage systems, is not always able to cope with the increased precipitation, sometimes leading to rainwater runoff and floods causing disturbances and damage to property. Therefore, there is a need to find new ways of managing drainage, such as Sustainable Urban Drainage Systems (SUDS). The research has highlighted the main driving forces behind the need for change, revealed by the participants, to the need to adopt new ideas and approaches for urban drainage. However, while moving towards this, certain factors that may hinder the aim of using the experiences of other countries and taking advantage of innovative solutions. The research illustrates an initial conceptual model for these factors emerging from the analysis. It identifies some of the fundamental issues affecting the resistance to change towards the adoption of the concept of sustainability in Saudi Arabia, with Riyadh city as a case study. This was by using a qualitative approach, whereby, through two phases of fieldwork during 2013 and 2014, twenty-six semi-structured interviews were conducted with a number of representative officials and professionals from key government departments and organisations related to urban drainage management. Grounded Theory approach was followed to analyse the qualitative data obtained. Resistance to change was classified to: firstly: individual inertia (e.g. familiarity with the conventional solutions and approaches, lack of awareness, and considering sustainability as a marginal matter in urban planning). This resulted in not paying the desired attention, and impact on planning and setting priorities for development. Secondly: institutionalised inertia (e.g. lack of technical and design specifications for other unconventional drainage solutions, lack of consideration by decision makers in other disciplines such as contributions from environmental and geographical studies, and routine work and bureaucracy). This contributes to the weakness of decision-making, weakness in the role of research, and a lack of human resources. It seems that attitudes towards change may have reduced the ability to move forward towards sustainable development, in addition to contributing towards difficulties in some aspects of the decision-making process. Thus, the chapter provides insights into the current situation in Saudi Arabia and contributes to understanding the decisions that are made regarding change.

Keywords: climate change, new knowledge and approaches, resistance to change, Saudi Arabia, SUDS, urban drainage, urban expansion

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Authors: Lin Meng, Xi Lu, Haibo Wang, Yong Song, Lili Cao, Wenfang Song, Yong Hu

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China has abundant heavy oil resources, and thermal recovery is the main recovery method for heavy oil reservoirs. However, high energy consumption, high carbon emission and high production costs make heavy oil thermal recovery unsustainable. It is urgent to explore a replacement for developing technology. A low Carbon and cost technology of heavy oil recovery, chemical viscosity-reduction in layer (CVRL), is developed by the petroleum exploration and development research institute of Sinopec via investigated mechanisms, synthesized products, and improved oil production technologies, as follows: (1) Proposed a cascade viscous mechanism of heavy oil. Asphaltene and resin grow from free molecules to associative structures further to bulk aggregations by π - π stacking and hydrogen bonding, which causes the high viscosity of heavy oil. (2) Aimed at breaking the π - π stacking and hydrogen bond of heavy oil, the copolymer of N-(3,4-dihydroxyphenethyl) acryl amide and 2-Acrylamido-2-methylpropane sulfonic acid was synthesized as a viscosity reducer. It achieves a viscosity reduction rate of>80% without shearing for heavy oil (viscosity < 50000 mPa‧s), of which fluidity is evidently improved in the layer. (3) Synthesized hydroxymethyl acrylamide-maleic acid-decanol ternary copolymer self-assembly plugging agent. The particle size is 0.1 μm-2 mm adjustable, and the volume is 10-500 times controllable, which can achieve the efficient transportation of viscosity reducer to enriched oil areas. CVRL has applied 400 wells until now, increasing oil production by 470000 tons, saving 81000 tons of standard coal, reducing CO2 emissions by 174000 tons, and reducing production costs by 60%. It promotes the transformation of heavy oil towards low energy consumption, low carbon emissions, and low-cost development.

Keywords: heavy oil, chemical viscosity-reduction, low carbon, viscosity reducer, plugging agent

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Authors: D. Ramajo, S. Corzo, M. Nigro

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A Multi-dimensional computational fluid dynamics (CFD) two-phase model was developed with the aim to simulate the in-core coolant circuit of a pressurized heavy water reactor (PHWR) of a commercial nuclear power plant (NPP). Due to the fact that this PHWR is a Reactor Pressure Vessel type (RPV), three-dimensional (3D) detailed modelling of the large reservoirs of the RPV (the upper and lower plenums and the downcomer) were coupled with an in-house finite volume one-dimensional (1D) code in order to model the 451 coolant channels housing the nuclear fuel. Regarding the 1D code, suitable empirical correlations for taking into account the in-channel distributed (friction losses) and concentrated (spacer grids, inlet and outlet throttles) pressure losses were used. A local power distribution at each one of the coolant channels was also taken into account. The heat transfer between the coolant and the surrounding moderator was accurately calculated using a two-dimensional theoretical model. The implementation of subcooled boiling and condensation models in the 1D code along with the use of functions for representing the thermal and dynamic properties of the coolant and moderator (heavy water) allow to have estimations of the in-core steam generation under nominal flow conditions for a generic fission power distribution. The in-core mass flow distribution results for steady state nominal conditions are in agreement with the expected from design, thus getting a first assessment of the coupled 1/3D model. Results for nominal condition were compared with those obtained with a previous 1/3D single-phase model getting more realistic temperature patterns, also allowing visualize low values of void fraction inside the upper plenum. It must be mentioned that the current results were obtained by imposing prescribed fission power functions from literature. Therefore, results are showed with the aim of point out the potentiality of the developed model.

Keywords: PHWR, CFD, thermo-hydraulic, two-phase flow

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Authors: Sotirios Longinos, Anna Loskutova, Assel Tolegenova, Assem Imanzhussip, Lei Wang

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Hot, dry rock (HDR) has substantial potential as a thermal energy source. It has been exploited by hydraulic fracturing to extract heat and generate electricity, which is a well-developed technique known for creating the enhanced geothermal systems (EGS). These days, LN2 is being tested as an environmental friendly fracturing fluid to generate densely interconnected crevices to augment heat exchange efficiency and production. This study examines experimentally the efficacy of LN2 cryogenic fracturing for granite samples in Kazakhstan with immersion method. A comparison of two different experimental models is carried out. The first mode is rock heating along with liquid nitrogen treatment (heating with freezing time), and the second mode is multiple times of heating along with liquid nitrogen treatment (heating with LN2 freezing-thawing cycles). The experimental results indicated that with multiple heating and LN2-treatment cycles, the permeability of granite first ameliorates with increasing number of cycles and later reaches a plateau after a certain number of cycles. On the other hand, density, P-wave velocity, uniaxial compressive strength, elastic modulus, and tensile strength indicate a downward trend with increasing heating and treatment cycles. The thermal treatment cycles do not seem to have an obvious effect on the Poisson’s ratio. The changing rate of granite rock properties decreases as the number of cycles increases. The deterioration of granite primarily happens within the early few cycles. The heating temperature during the cycles shows an important influence on the deterioration of granite. More specifically, mechanical deterioration and permeability amelioration become more remarkable as the heating temperature increases.LN2 fracturing generates many positives compared to conventional fracturing methods such as little water consumption, requirement of zero chemical additives, lessening of reservoir damage, and so forth. Based on the experimental observations, LN2 can work as a promising waterless fracturing fluid to stimulate hot, dry rock reservoirs.

Keywords: granite, hydraulic fracturing, liquid nitrogen, Kazakhstan

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Authors: Aimen Saleh

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The Silurian Lower Acacus sandstone is one of the main reservoirs in North West Libya. Our aim in this study is to grasp a robust understanding of the hydrocarbon potential and distribution in the area. To date, the depositional environment of the Lower Acacus reservoir still open to discussion and contradiction. Henceforth, building three dimensional (3D) property modelling is one way to support the analysis and description of the reservoir, its properties and characterizations, so this will be of great value in this project. The 3D model integrates different data set, these incorporates well logs data, petrophysical reservoir properties and seismic data as well. The finalized depositional environment model of the Lower Acacus concludes that the area is located in a deltaic transitional depositional setting, which ranges from a wave dominated delta into tide dominated delta type. This interpretation carried out through a series of steps of model generation, core description and Formation Microresistivity Image tool (FMI) interpretation. After the analysis of the core data, the Lower Acacus layers shows a strong effect of tidal energy. Whereas these traces found imprinted in different types of sedimentary structures, for examples; presence of some crossbedding, such as herringbones structures, wavy and flaser cross beddings. In spite of recognition of some minor marine transgression events in the area, on the contrary, the coarsening upward cycles of sand and shale layers in the Lower Acacus demonstrate presence of a major regressive phase of the sea level. However, consequently, we produced a final package of this model in a complemented set of facies distribution, porosity and oil presence. And also it shows the record of the petroleum system, and the procedure of Hydrocarbon migration and accumulation. Finally, this model suggests that the area can be outlined into three main segments of hydrocarbon potential, which can be a textbook guide for future exploration and production strategies in the area.

Keywords: Acacus, Ghadames , Libya, Silurian

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Authors: J. Satya Eswari, J. Sekhar Babub, Meena Murmu, Govardhan Bhat

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Electrical Discharge Machining (EDM) is an unconventional manufacturing process based on removal of material from a part by means of a series of repeated electrical sparks created by electric pulse generators at short intervals between a electrode tool and the part to be machined emmersed in dielectric fluid. In this paper, a study will be performed on the influence of the factors of peak current, pulse on time, interval time and power supply voltage. The output responses measured were material removal rate (MRR) and surface roughness. Finally, the parameters were optimized for maximum MRR with the desired surface roughness. RSM involves establishing mathematical relations between the design variables and the resulting responses and optimizing the process conditions. RSM is not free from problems when it is applied to multi-factor and multi-response situations. Design of experiments (DOE) technique to select the optimum machining conditions for machining AISI 4140 using EDM. The purpose of this paper is to determine the optimal factors of the electro-discharge machining (EDM) process investigate feasibility of design of experiment techniques. The work pieces used were rectangular plates of AISI 4140 grade steel alloy. The study of optimized settings of key machining factors like pulse on time, gap voltage, flushing pressure, input current and duty cycle on the material removal, surface roughness is been carried out using central composite design. The objective is to maximize the Material removal rate (MRR). Central composite design data is used to develop second order polynomial models with interaction terms. The insignificant coefficients’ are eliminated with these models by using student t test and F test for the goodness of fit. CCD is first used to establish the determine the optimal factors of the electro-discharge machining (EDM) for maximizing the MRR. The responses are further treated through a objective function to establish the same set of key machining factors to satisfy the optimization problem of the electro-discharge machining (EDM) process. The results demonstrate the better performance of CCD data based RSM for optimizing the electro-discharge machining (EDM) process.

Keywords: electric discharge machining (EDM), modeling, optimization, CCRD

Procedia PDF Downloads 338