Search results for: Rare vascular phenomenon

Authors: Serkan Solmaz, Jean-Baptiste Gouriet, Nicolas Van de Wyer, Christophe Schram

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Efficiency of the cooling process for cryogenic propellant boiling in engine cooling channels on space applications is relentlessly affected by the phase change occurs during the boiling. The effectiveness of the cooling process strongly pertains to the type of the boiling regime such as nucleate and film. Geometric constraints like a non-transparent cooling channel unable to use any of visualization methods. The ultrasonic (US) technique as a non-destructive method (NDT) has therefore been applied almost in every engineering field for different purposes. Basically, the discontinuities emerge between mediums like boundaries among different phases. The sound wave emitted by the US transducer is both transmitted and reflected through a gas-liquid interface which makes able to detect different phases. Due to the thermal and structural concerns, it is impractical to sustain a direct contact between the US transducer and working fluid. Hence the transducer should be located outside of the cooling channel which results in additional interfaces and creates ambiguities on the applicability of the present method. In this work, an exploratory research is prompted so as to determine detection ability and applicability of the US technique on the cryogenic boiling process for a cooling cycle where the US transducer is taken place outside of the channel. Boiling of the cryogenics is a complex phenomenon which mainly brings several hindrances for experimental protocol because of thermal properties. Thus substitute materials are purposefully selected based on such parameters to simplify experiments. Aside from that, nucleate and film boiling regimes emerging during the boiling process are simply simulated using non-deformable stainless steel balls, air-bubble injection apparatuses and air clearances instead of conducting a real-time boiling process. A versatile detection algorithm is perennially developed concerning exploratory studies afterward. According to the algorithm developed, the phases can be distinguished 99% as no-phase, air-bubble, and air-film presences. The results show the detection ability and applicability of the US technique for an exploratory purpose.

Keywords: Ultrasound, ultrasonic, multiphase flow, boiling, cryogenics, detection algorithm

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Authors: Mark Bezner, Shani Deri, Tom Trigano, Kfir Ben-Harush

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Intermediate filament (IF) proteins-based fibers are among the toughest fibers in nature, as was shown by native hagfish slime threads and by synthetic fibers that are based on type V IF-proteins, the nuclear lamins. It is assumed that their mechanical performance stems from two major factors: (1) the transition from elastic -helices to stiff-sheets during tensile load; and (2) the specific organization of the coiled-coil proteins into a hierarchical network of nano-filaments. Here, we investigated the interrelationship between these two factors by using wet-spun fibers based on C. elegans (Ce) lamin. We found that Ce-lamin fibers, whether assembled in aqueous or alcoholic solutions, had the same nonlinear mechanical behavior, with the elastic region ending at ~5%. The pattern of the transition was, however, different: the ratio between -helices and -sheets/random coils was relatively constant until a 20% strain for fibers assembled in an aqueous solution, whereas for fibers assembled in 70% ethanol, the transition ended at a 6% strain. This structural phenomenon in alcoholic solution probably occurred through the transition between compacted and extended conformation of the random coil, and not between -helix and -sheets, as cycle analyses had suggested. The different transition pattern can also be explained by the different higher order organization of Ce-lamins in aqueous or alcoholic solutions, as demonstrated by introducing a point mutation in conserved residue in Ce-lamin gene that alter the structure of the Ce-lamins’ nano-fibrils. In addition, biomimicking the layered structure of silk and hair fibers by coating the Ce-lamin fiber with a hydrophobic layer enhanced fiber toughness and lead to a reversible transition between -helix and the extended conformation. This work suggests that different hierarchical structures, which are formed by specific assembly conditions, lead to diverse secondary structure transitions patterns, which in turn affect the fibers’ mechanical properties.

Keywords: protein-based fibers, intermediate filaments (IF) assembly, toughness, structure-property relationships

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Authors: Dahna Alkahtani, Faryal Suraya, Fadah Alanazi

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Background: Buccal mucosal graft for urethral augmentation has surpassed other grafting options, and is now considered the standard of choice for substitution Urethroplasty. The graft has gained its popularity due to its excellent short and long-term results, easy harvesting as well as its ability in withstanding wet environments. However, although Buccal mucosal grafts are an excellent option, it is not free of complications, potential intraoral complications are bleeding, pain, swelling, injury to the nerve resulting in numbness, lip deviation or retraction. Objectives: The current study aims to evaluate the intraoral complications of buccal mucosa grafts harvested from one cheek, and used in Augmentation Urethroplasty. Methodology: The study was conducted retrospectively using the medical records of patients who underwent open augmentation urethroplasty with a buccal mucosa graft at King Khalid University Hospital, Saudi Arabia. Data collection of demographics included the type of graft used, presence or absence of strictures and its etiological factors. Pre-operative and post-operative evaluations were carried out on the subjects including the medical history, physical examination, uroflowmetry, retrograde urethrography, voiding cystourethrography and urine cultures were also noted. Further, the quality of life and complications of the procedure including the presence or occurrence of bleeding within 3-days post-procedure, the severity of pain, oral swelling after grafting, length of return to normal daily diet, painful surgical site, intake of painkillers, presence or absence of speech disturbance, numbness in the cheeks and lips were documented. Results: Thirty-two male subjects with ages ranging from 15 years to 72 years were included in the current study. Following the procedure, a hundred percent of the subjects returned to their normal daily diet by the sixth postoperative day. Further, the majority of the patients reported experiencing mild pain accounting for 61.3%, and 90.3% of the subjects reported using painkillers to control the pain. Surgical wound Pain was reportedly more common at the perineal site as 48.4% of the subjects experienced it; on the other hand, 41.9% of the patients experienced pain in the oral mucosa. The presence of speech disorders, as assessed through medical history, was found to be present in 3.2% of patients. The presence of numbness in the cheeks and lips was found in 3.2% of patients. Other complications such as parotid duct injury, delayed wound healing, non-healing wound and suture granuloma were rare as 90.3% of the subjects denied experiencing any of them, there were nonetheless reports of parotid duct injury by 6.5% of the patients, and non-healing wound by the 3.2% of patients. Conclusion: Buccal Mucosa Graft in Augmentation Urethroplasty is an ideal source of allograft, although not entirely painless; it is considerably safe with minimal intra-oral complication and undetectable strain on the patients’ quality of life.

Keywords: augmentation, buccal, graft, oral

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Authors: Sabah Khan

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The idea of universal Islam tends to exaggerate the extent of homogeneity in Islamic beliefs and practices across Muslim communities. In the age of migration, various Muslim communities are in diaspora. The immediate implication of this is what happens to Islam in diaspora? How Islam gets represented in new forms? Such pertinent questions need to be dealt with. This paper shall draw on the idea of religious transnationalism, primarily transnational Islam. There are multiple ways to conceptualize transnational phenomenon with reference to Islam in terms of flow of people, transnational organizations and networks; Ummah oriented solidarity and the new Muslim public sphere. This paper specifically deals with the new Muslim public sphere. It primarily refers to the space and networks enabled by new media and communication technologies, whereby Muslim identity and Islamic normativity are rehearsed, debated by people in different locales. A new sense of public is emerging across Muslim communities, which needs to be contextualized. This paper uses both primary and secondary data. Primary data elicited through content analysis of audio-visuals on social media and secondary sources of information ranging from books, articles, journals, etc. The basic aim of the paper is to focus on the emerging Muslim public sphere and the role of media in expanding public spheres of Islam. It also explores how Muslims in diaspora negotiate Islam and Islamic practices through media and the new Muslim public sphere. This paper cogently weaves in discussions firstly, of re-intellectualization of Islamic discourse in the public sphere. In other words, how Muslims have come to reimagine their collective identity and critically look at fundamental principles and authoritative tradition. Secondly, the emerging alternative forms of Islam by young Muslims in diaspora. In other words, how young Muslims search for unorthodox ways and media for religious articulation, including music, clothing and TV. This includes transmission and distribution of Islam in diaspora in terms of emerging ‘media Islam’ or ‘soundbite Islam’. The new Muslim public sphere has offered an arena to a large number of participants to critically engage with Islam, which leads not only to a critical engagement with traditional forms of Islamic authority but also emerging alternative forms of Islam and Islamic practices.

Keywords: Islam, media, Muslims, public sphere

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Authors: Myriam Benraad

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On 5 July 2016, just days before the bloody terrorist attack on the Promenade des Anglais in Nice, the Al-Hayat media centre, one of the official propaganda branches of the Islamic State, broadcast a French nasheed which paid tribute to the Paris and Brussels attacks of November 2015 and March 2016. Entitled 'My Revenge', the terrorist anthem was of rare vehemence. It mentioned, sequentially, 'huddled bodies', in a reference to the civilian casualties of Western air strikes in the Iraqi-Syrian zone, 'explosive belts', 'sharp knives', 'large-calibre weapons' as well as 'localised targets'. France was accused of bearing the responsibility for the wave of attacks on its territory since the Charlie Hebdo massacre of January 2015 due to its 'ruthless war' against the Muslim world. Evoking an 'old aggression' and the 'crimes and spoliations' of which France has made itself guilty, the jihadist hymn depicted the rebirth of the caliphate as 'laudable revenge'. The notion of revenge has always been central to contemporary jihadism, understood both as a revolutionary ideology and a global militant movement. In recent years, the attacks carried out in Europe and elsewhere in the world have, for most, been claimed in its name. Whoever says jihad, says drama, yet few studies, if any, have looked at its dramatic and emotional elements, most notably its tragic vengefulness. This seems all the more astonishing that jihad is filled with drama; it could even be seen as a drama in its own right. The jihadists perform a script and take on roles inspired by their respective group’s culture (norms, values, beliefs, and symbols). The militants stage and perform such a script for a designated audience, either partisan, sympathising or hostile towards them and their cause. This research paper will examine the dramaturgy of jihadism and in particular, the genre that best characterises its violence: revenge tragedy. Theoretically, the research will rely on the tools of social movement theory and the sociology of emotions. Methodologically, it will draw from dramaturgical analysis and a combination of qualitative and quantitative tools to attain valuable observations of a number of developments, trends, and patterns. The choice has been made to focus mainly – however not exclusively – on the attacks which have taken place since 2001 in the European Union and more specific member states that have been significantly hit by jihadist terrorism. The research looks at a number of representative longitudinal samples identifying continuities and discontinuities, similarities, but also substantial differences. The preliminary findings tend to establish the relevance and validity of this approach in helping make better sense of sensitisation, mobilisation, and survival dynamics within jihadist groups, and motivations among individuals who have embraced violence. Besides, they illustrate their pertinence for counterterrorism policymakers and practitioners. Through drama, jihadist groups ensure the unceasing regeneration of their militant cause as well as their legitimation among their partisans. Without drama, and without the spectacular ideological staging of reality, they would not be able to maintain their attraction potential and power of persuasion.

Keywords: Jihadism, dramaturgy, revenge, tragedy

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Authors: Harper Staples

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A necessary outcome of today’s contemporary globalised reality, current views of multilingualism hold that it no longer represents the exception, but rather the rule. As such, the simultaneous acquisition of multiple languages represents a common experience for many of today's students and therefore represents a key area of inquiry in the domain of foreign language learner identity. Second and multilingual language acquisition processes parallel each other in many ways; however, there are differences to be found in the ways in which a student may learn a third language. A multilingual repertoire will have to negotiate complex change as language competencies dynamically evolve; moreover, this process will vary according to the contextual factors attributed to a unique learner. A developing multilingual identity must, therefore, contend with an array of potential challenges specific to the individual in question. Despite an overarching recognition in the literature that pluri-language acquisition represents a unique field of inquiry within applied linguistic research, there is a paucity of empirical work which examines the ways in which individuals construct a sense of their own identity as multilingual speakers in such contexts of learning. This study explores this phenomenon via a mixed-methods, comparative case study approach at four school sites based in Finland, France, Wales, and England. It takes a strongly individual-in-context view, conceptualising each adolescent participant in dynamic terms in order to undertake a holistic exploration of the myriad factors that might impact upon, and indeed be impacted by, a learner's developing multilingual identity. Emerging themes of note thus far suggest that, beyond the expected divergences in the experience of multilinguality at the individual level, there are contradictions in the way in which adolescent students in each site 'claim' their plurilingualism. This can be argued to be linked to both meso and macro-level factors, including the foreign language curriculum and, more broadly, societal attitudes towards multilingualism. These diverse emergent identifications have implications not only for attainment in the foreign language but also for student well-being more generally.

Keywords: foreign language learning, student identity, multilingualism, educational psychology

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Authors: Mohamed Khiatine, Amal Medjnoun, Ramdane Bahar

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The North Algeria is a highly seismic zone, as evidenced by the historical seismicity. During the past two decades, it has experienced several moderate to strong earthquakes. Therefore, the geotechnical engineering problems that involve dynamic loading of soils and soil-structure interaction system requires, in the presence of saturated loose sand formations, liquefaction studies. Bejaia city, located in North-East of Algiers, Algeria, is a part of the alluvial plain which covers an area of approximately 750 hectares. According to the Algerian seismic code, it is classified as moderate seismicity zone. This area had not experienced in the past urban development because of the different hazards identified by hydraulic and geotechnical studies conducted in the region. The low bearing capacity of the soil, its high compressibility and the risk of liquefaction and flooding are among these risks and are a constraint on urbanization. In this area, several cases of structures founded on shallow foundations have suffered damages. Hence, the soils need treatment to reduce the risk. Many field and laboratory investigations, core drilling, pressuremeter test, standard penetration test (SPT), cone penetrometer test (CPT) and geophysical down hole test, were performed in different locations of the area. The major part of the area consists of silty fine sand , sometimes heterogeneous, has not yet reached a sufficient degree of consolidation. The ground water depth changes between 1.5 and 4 m. These investigations show that the liquefaction phenomenon is one of the critical problems for geotechnical engineers and one of the obstacles found in design phase of projects. This paper presents an analysis to evaluate the liquefaction potential, using the empirical methods based on Standard Penetration Test (SPT), Cone Penetration Test (CPT) and shear wave velocity and numerical analysis. These liquefaction assessment procedures indicate that liquefaction can occur to considerable depths in silty sand of harbor zone of Bejaia.

Keywords: earthquake, modeling, liquefaction potential, laboratory investigations

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Authors: Feng-Ming Fan, Xiu-Hui Wen, Po-Feng Chen, Yi-Ching Tu

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Because of inborn natural conditions and man-made sabotage, the water resources insufficient phenomenon in Taiwan is a very important issue needed to face immediately. The regulations and law of water resources protection and recycling are gradually completed now but still lack of specific water recycling effectiveness checking method. The research focused on the industrial parks that already had been certificated with EIA to establish a professional checking system, carry through and forge ahead to contribute one’s bit in water resources sustainable usage. Taiwan Government Policies of Environmental Impact Assessment established in 1994, some development projects were requested to set certain water recycling ratio for water resources effective usage. The water covers and contains everything because all-inclusive companies enter and be stationed. For control the execution status of industrial park water and waste water recycling ratio about EIA commitment effectively, we invited experts and scholars in this filed to discuss with related organs to formulate the policy and audit plan. Besides, call a meeting to set public version water equilibrium diagrams and recycles parameter. We selected nine industrial parks that were requested set certain water recycling ratio in EIA examination stage and then according to the water usage quantity, we audited 340 factories in these industrial parks with spot and documents examination and got fruitful results – the average water usage of unit area per year of all these examined industrial parks is 31,000 tons/hectare/year, the value is just half of Taiwan industries average. It is obvious that the industrial parks with EIA commitment can decrease the water resources consumption effectively. Taiwan government policies of Environmental Impact Assessment took follow though tracking function into consideration at the beginning. The results of this research verify the importance of the implementing with water recycling to save water resources in EIA commitment. Inducing development units to follow EIA commitment to get the balance between environmental protection and economic development is one of the important EIA value.

Keywords: Taiwan government policies of environmental impact assessment, water recycling ratio of EIA commitment, water resources sustainable usage, water recycling

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Authors: Zahra Kazemi Saleh, Bénédicte Poulin-Charronnat, Annie Vinter

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This study examines the effects of aging on visual statistical learning, using eye-tracking techniques to investigate this cognitive phenomenon. Visual statistical learning is a fundamental brain function that enables the automatic and implicit recognition, processing, and internalization of environmental patterns over time. Some previous research has suggested the robustness of this learning mechanism throughout the aging process, underscoring its importance in the context of education and rehabilitation for the elderly. The study included three distinct groups of participants, including 21 young adults (Mage: 19.73), 20 young-old adults (Mage: 67.22), and 17 old-old adults (Mage: 79.34). Participants were exposed to a series of 12 arbitrary black shapes organized into 6 pairs, each with different spatial configurations and orientations (horizontal, vertical, and oblique). These pairs were not explicitly revealed to the participants, who were instructed to passively observe 144 grids presented sequentially on the screen for a total duration of 7 min. In the subsequent test phase, participants performed a two-alternative forced-choice task in which they had to identify the most familiar pair from 48 trials, each consisting of a base pair and a non-base pair. Behavioral analysis using t-tests revealed notable findings. The mean score for the first group was significantly above chance, indicating the presence of visual statistical learning. Similarly, the second group also performed significantly above chance, confirming the persistence of visual statistical learning in young-old adults. Conversely, the third group, consisting of old-old adults, showed a mean score that was not significantly above chance. This lack of statistical learning in the old-old adult group suggests a decline in this cognitive ability with age. Preliminary eye-tracking results showed a decrease in the number and duration of fixations during the exposure phase for all groups. The main difference was that older participants focused more often on empty cases than younger participants, likely due to a decline in the ability to ignore irrelevant information, resulting in a decrease in statistical learning performance.

Keywords: aging, eye tracking, implicit learning, visual statistical learning

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Authors: Dinuka Herath, Shelley Harrington

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This paper prompts debate about whether disorganization can be positioned as a mechanism that facilitates the creation and enactment of important dynamic capabilities within an organization. This particular article is a conceptual exploration of the link between dynamic capabilities and disorganization and presents the case for agent-based modelling as a viable methodological tool which can be used to explore this link. Dynamic capabilities are those capabilities that an organization needs to sustain competitive advantage in complex environments. Disorganization is the process of breaking down restrictive organizational structures and routines that commonly reside in organizations in order to increase organizational performance. In the 20th century, disorganization was largely viewed as an undesirable phenomenon within an organization. However, the concept of disorganization has been revitalized and garnered research interest in the recent years due to studies which demonstrate some of the advantages of disorganization to an organization. Furthermore, recent Agent-based simulation studies have shown the capability of disorganization to be managed and argue for disorganization to be viewed as an enabler of organizational productivity. Given the natural state of disorganization and resulting fear this can create, this paper argues that instead of trying to ‘correct’ disorganization, it should be actively encouraged to have functional purpose. The study of dynamic capabilities emerged as a result of heightened dynamism and consequentially the very nature of dynamism denotes a level of fluidity and flexibility, something which this paper argues many organizations do not truly foster due to a constrained commitment to organization and order. We argue in this paper that the very state of disorganization is a state that should be encouraged to develop dynamic capabilities needed to not only deal with the complexities of the modern business environment but also to sustain competitive success. The significance of this paper stems from the fact that both dynamic capabilities and disorganization are two concepts that are gaining prominence in their respective academic genres. Despite the attention each concept has received individually, no conceptual link has been established to depict how they actually interact with each other. We argue that the link between these two concepts present a novel way of looking at organizational performance. By doing so, we explore the potential of these two concepts working in tandem in order to increase organizational productivity which has significant implications for both academics and practitioners alike.

Keywords: agent-based modelling, disorganization, dynamic capabilities, performance

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Authors: Abouchouaib Belahmira, Joerg W. Schneider, Hafid Saber

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Continental sediments of the uppermost Carboniferous (late Pennsylvanian) El Menizla and Oued Issene formations of the Souss basin, Southwestern High Atlas Mountains, Morocco have yielded abundant well-preserved arthropods. The latter comprise freshwater and terrestrial elements, were found associated with plants, freshwater jellyfish and pelecypods. Arthropods are ubiquitous and typically restricted to the dominated lacustrine black shale taphofacies. The lithofacies interpretation and its correlation with the taphofacies led to the determination of the original depositional environment that was reconstructed as a fluvial-dominated with braided wide channel system and floodplain lakes to peat local backswamps sub-environments. The late Carboniferous fossiliferous strata have been correlated biostratigraphically with many other Pennsylvanian (Kasimovian/Gzhelian) deposits of North America and Europe on the basis of entomological studies. The faunal elements of the lentic biocoenosis of the Souss basin are depauperate, with the vagile forms slightly diverse than sessile ones. The prevailing groups are small shelly fauna, other habitat guild such as apterygotan Monura insect dasyleptids. The fossils recorded from the Souss basin includes crustaceans, of various sizes (µm- to mm) and morphologies, preservation state ranging from poorly preserved to rarely well-preserved specimens. Their remains sporadically found clustered and preserved as internal or external shell molds or steinkerns often disarticulated specimens. Ostracods as more likely Carbonita, their shells are preserved three-dimensionally. The clam shrimps conchostracans record of the Souss basin are often determined as pseudestherids and the Spinicaudatan leaiids. The moldic preservation is somewhat similar to pelecypods, they are known from internal casts or impressions. Monura insects are characterized by their low diversity, thus, only two species are known Dasyleptus lucasi Brongniart and Dasyleptus noli Rasnitsyn. The terrestrial component consists of pterygotan insects. They are diverse, significantly more frequent throughout the Souss basin fossil localities, numerically dominated by the members of Blattodea (cockroaches). The fossil record includes Blattodea, Protorthoptera, Diaphanopterodea, Ephemeroptera (mayfly) , Calneurodea, Grylloblattodea, Miomoptera and Palaeodictyoptera. Additionally, the composition of the preserved insect is mostly represented by completely isolated forewings, rare membranous hindwings, parts of the body or exceptionally preserved specimens, which may reflect a wide spectrum of taphonomic pathways. The steady increase in taxonomic diversity of fossil sites in the Souss basin, together with the taphonomic interpretation of arthropods assemblages, have contributed to provide a novel insight into the complex terrestrial ecosystem that thrived in this paleotropical key region during the late Pennsylvanian and additionally to understand climate-driven paleobiogeography and paleoecology of late Paleozoic non-marine arthropods.

Keywords: Souss, carboniferous, arthropods, taphonomy, paleoecology.

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Authors: Timma Reddy, Srikonda Ramesh

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India has been traditionally vulnerable to natural disasters such as Floods, droughts, cyclones, earthquakes and landslides. It has become a recurrent phenomenon as observed in last five decades. The survey indicates that about 60% of the landmass is prone to earthquakes of various intensities; over 40 million hectares is prone to floods; about 8% of the total area is prone to cyclones and 68% of the area is susceptible to drought. Climate change is likely to be perceived through experience of extreme weather events. There is growing societal concern about climate change, given the potential impacts of associated natural hazards such as cyclones, flooding, earthquakes, landslides etc, hence it is essential and crucial to strengthening our settlements to respond to such calamities. So, the research paper focus is to analyze the effective planning strategy/mechanism to integrate disaster mitigation measures in coastal regions in general and Capital Region of Andhra Pradesh in particular. The basic hypothesis is to govern the appropriate special planning considerations would facilitate to have organized way of protective life and properties from natural disasters. And further to integrate the infrastructure planning with conscious direction would provide an effective mitigations measures. It has been planned and analyzed to Vijayawada city with conscious land use planning with reference to space syntax trajectory in accordance to required social infrastructure such as health facilities, institution areas and recreational and other open spaces. It has been identified that the geographically ideal location with reference to the population densities based on GIS tools the properness strategies can be effectively integrated to protect the life and to save the properties by means of reducing the damage/impact of natural disasters in general earth quake/cyclones or floods in particularly.

Keywords: modular, trajectories, social infrastructure, evidence based syntax, drills and equipments, GIS, geographical micro zoning, high resolution satellite image

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Authors: Zelalem B. Gurmessa, Ignatius W. Ferreira, Henry F. Wissink

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The aim of this paper is to critically examine the factors contributing to academic brain drain in the Sub-Saharan Africa with specific reference to the higher education sector. Africa in general and Sub-Saharan African (SSA) countries, in particular, are experiencing an exodus of highly trained, qualified and competent human resources to other developing and developed countries thereby threatening the overall development of the relevant regions and impeding both public and private service delivery systems in the nation states. The region is currently in a dire situation in terms of health care services, education, science, and technology. The contribution of SSA countries to Science, Technology and Innovation is relatively minimal owing to the migration of skilled professionals due to both push and pull factors. The phenomenon calls for both international and trans-boundary, regional, national and institutional interventions to curb the exodus. Based on secondary data and the review of the literature, the article conceptualizes the antecedents and impacts of human capital flight or brain drain in the SSA countries from a higher education perspective. To this end, the article explores the magnitude, causes, and impacts of brain drain in the region. Despite the lack of consistent data on the magnitude of academic brain drain in the region, a critical analysis of the existing sources shows that pay disparity between developing and developed countries, the lack of enabling working conditions at source countries, fear of security due to political turmoil or unrest, the availability of green pastures and opportunity for development in the receiving countries were identified as major factors contributing to academic brain drain in the region. This hampers the socio-economic, technological and political development of the region. The paper also recommends that further research can be undertaken on the magnitude, causes, characteristics and impact of brain drain on the sustainability and competitiveness of SSA higher education institutions in the region.

Keywords: brain drain, higher education, sub-Saharan Africa, sustainable development

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Authors: Jinchen Cao, Tiantian Du

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As waxy crude oil is easy to crystallization and deposition in the pipeline wall, it causes pipeline clogging and leads to the reduction of oil and gas gathering and transmission efficiency. In this paper, a mesoscopic scale dissipative particle dynamics method is employed, and constructed four pipe wall models, including smooth wall (SW), hydroxylated wall (HW), rough wall (RW), and single-layer graphene wall (GW). Snapshots of the simulation output trajectories show that paraffin molecules interact with each other to form a network structure that constrains water molecules as their nucleation sites. Meanwhile, it is observed that the paraffin molecules on the near-wall side are adsorbed horizontally between inter-lattice gaps of the solid wall. In the pressure range of 0 - 50 MPa, the pressure change has less effect on the affinity properties of SS, HS, and GS walls, but for RS walls, the contact angle between paraffin wax and water molecules was found to decrease with the increase in pressure, while the water molecules showed the opposite trend, the phenomenon is due to the change in pressure, leading to the transition of paraffin wax molecules from amorphous to crystalline state. Meanwhile, the minimum crystalline phase pressure (MCPP) was proposed to describe the lowest pressure at which crystallization of paraffin molecules occurs. The maximum number of crystalline clusters formed by paraffin molecules at MCPP in the system showed NSS (0.52 MPa) > NHS (0.55 MPa) > NRS (0.62 MPa) > NGS (0.75 MPa). The MCPP on the graphene surface, with the least number of clusters formed, indicates that the addition of graphene inhibited the crystallization process of paraffin deposition on the wall surface. Finally, the thermal conductivity was calculated, and the results show that on the near-wall side, the thermal conductivity changes drastically due to the occurrence of adsorption crystallization of paraffin waxes; on the fluid side the thermal conductivity gradually tends to stabilize, and the average thermal conductivity shows: ĸRS(0.254W/(m·K)) > ĸRS(0.249W/(m·K)) > ĸRS(0.218W/(m·K)) > ĸRS(0.188W/(m·K)).This study provides a theoretical basis for improving the transport efficiency and heat transfer characteristics of waxy crude oil in terms of wall type, wall roughness, and MCPP.

Keywords: waxy crude oil, thermal conductivity, crystallization, dissipative particle dynamics, MCPP

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Authors: Ilana Margalith, Adaya Meirowitz, Sigalit Cohavi

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Violence against health professionals by patients and their families have recently become a disturbing phenomenon worldwide, exacting psychological as well as economic tolls. Health workplaces in Israel (e.g. hospitals and H.M.O clinics) provide workshops for their employees, supplying them with coping strategies. However, these workshops do not focus on nursing students, who are also subjected to this violence. Their learning environment is no longer as protective as it used to be. Furthermore, coping with violence was not part of the curriculum for Israeli nursing students. Thus, based on human aggression theories which depict the pivotal role of the professional's correct response in preventing the onset of an aggressive response or the escalation of violence, a workshop was developed for undergraduate nursing students at the Clalit Nursing Academy, Rabin Campus (Dina), Israel. The workshop aimed at reducing students' anxiety vis a vis the aggressive patient or family in addition to strengthening their ability to cope with such situations. The students practiced interpersonal skills, especially relevant to early detection of potential violence, as well as ‘a correct response’ reaction to the violence, thus developing the necessary steps to be implemented when encountering violence in the workplace. In order to assess the efficiency of the workshop, the participants filled out a questionnaire comprising knowledge and self-efficacy scales. Moreover, the replies of the 23 participants in this workshop were compared with those of 24 students who attended a standard course on interpersonal communication. Students' self-efficacy and knowledge were measured in both groups before and after the course. A statistically significant interaction was found between group (workshop/standard course) and time (before/after) as to the influence on students' self-efficacy (p=0.004) and knowledge (p=0.007). Nursing students, who participated in this ‘coping with workplace violence’ workshop, gained knowledge, confidence and a sense of self-efficacy with regard to workplace violence. Early detection of signs of imminent violence amongst patients or families and the prevention of its escalation, as well as the ability to manage the threatening situation when occurring, are acquired skills. Encouraging nursing students to learn and practice these skills may enhance their ability to cope with these unfortunate occurrences.

Keywords: early detection of violence, nursing students, patient aggression, self-efficacy, workplace violence

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Authors: Sonia A. Stoica, Lexi Frankel, Amalia Ardeljan, Selena Rashid, Ali Yasback, Omar Rashid

Abstract:

Introduction Enterococcus is a vast genus of lactic acid bacteria, gram-positivecocci species. They are common commensal organisms in the intestines of humans: E. faecalis (90–95%) and E. faecium (5–10%). Rare groups of infections can occur with other species, including E. casseliflavus, E. gallinarum, and E. raffinosus. The most common infections caused by Enterococcus include urinary tract infections, biliary tract infections, subacute endocarditis, diverticulitis, meningitis, septicemia, and spontaneous bacterial peritonitis. The treatment for sensitive strains of these bacteria includes ampicillin, penicillin, cephalosporins, or vancomycin, while the treatment for resistant strains includes daptomycin, linezolid, tygecycline, or streptogramine. Enterococcus faecalis CECT7121 is an encouraging nominee for being considered as a probiotic strain. E. faecalis CECT7121 enhances and skews the profile of cytokines to the Th1 phenotype in situations such as vaccination, anti-tumoral immunity, and allergic reactions. It also enhances the secretion of high levels of IL-12, IL-6, TNF alpha, and IL-10. Cytokines have been previously associated with the development of cancer. The intention of this study was to therefore evaluate the correlation between Enterococcus infections and incidence of bone carcinoma. Methods A retrospective cohort study (2010-2019) was conducted through a Health Insurance Portability and Accountability Act (HIPAA) compliant national database and conducted using International Classification of Disease (ICD) 9th and 10th codes for bone carcinoma diagnosis in a previously Enterococcus infected population. Patients were matched for age range and Charlson Comorbidity Index (CCI). Access to the database was granted by Holy Cross Health for academic research. Chi-squared test was used to assess statistical significance. Results A total number of 17,056 patients was obtained in Enterococcus infected group as well as in the control population (matched by Age range and CCI score). Subsequent bone carcinoma development was seen at a rate of 1.07% (184) in the Enterococcal infectious group and 3.42% (584) in the control group, respectively. The difference was statistically significant by p= 2.2x10-¹⁶, Odds Ratio = 0.355 (95% CI 0.311 - 0.404) Treatment for enterococcus infection was analyzed and controlled for in both enterococcus infected and noninfected populations. 78 out of 6,624 (1.17%) patients with a prior enterococcus infection and treated with antibiotics were compared to 202 out of 6,624 (3.04%) patients with no history of enterococcus infection (control) and received antibiotic treatment. Both populations subsequently developed bone carcinoma. Results remained statistically significant (p<2.2x10-), Odds Ratio=0.456 (95% CI 0.396-0.525). Conclusion This study shows a statistically significant correlation between Enterococcus infection and a decreased incidence of bone carcinoma. The immunologic response of the organism to Enterococcus infection may exert a protecting mechanism from developing bone carcinoma. Further exploration is needed to identify the potential mechanism of Enterococcus in reducing bone carcinoma incidence.

Keywords: anti-tumoral immunity, bone carcinoma, enterococcus, immunologic response

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Authors: Cristina Gutiérrez Carranza

Abstract:

Digital nomadism is a trend and lifestyle which combines work and traveling. This tourism tendency is motivated by the desire to have a fixed source of financial income while becoming independent from a specific work location. This study contextualizes Costa Rica and its potential prospects to take advantage of this tourism market niche. It explores the dynamics of digital nomadism in the context of Costa Rica, analyzing the current scenario, challenges, and opportunities related to this global phenomenon. The research covers several areas, including the conceptualization of digital nomadism, its historical background, and contemporary manifestations. The investigation delves into the present state of digital nomadism, evaluating the extent of digitalization in Costa Rica, mobile phone coverage, and fixed internet access. As part of the strategies implemented, as the study develops, mapping the most common destinations of digital nomads is a key factor, bringing a sight on the aspects that make Costa Rica an attractive location for this emerging tourist group. Additionally, the paper draws insights from hosting entrepreneurs and digital nomads with work visas in Costa Rica, offering a comprehensive understanding of the experiences and perspectives from both sides. Hence, the study includes data from a sample of 20 digital nomads holding visas for Costa Rica, offering a detailed analysis of their professional activities, experiences and needs as remote workers in the country. As well it adds in perceptions from 10 entrepreneurs engaged in providing accommodation services to digital nomads contribute to a degree of understanding of the way they have faced this growing movement. This research provides significant insights on the dynamics of digital nomadism in Costa Rica by integrating data from specific sources. Policymakers, entrepreneurs, and other stakeholders are anticipated to gain valuable data from the findings regarding the opportunities and challenges of hosting and accommodating digital nomads, which will ultimately aid in the creation of plans to capitalize on this worldwide trend for the nation's socioeconomic development.

Keywords: digital nomads, tourism, sustainability, digital nomads visa, remote jobs

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Authors: Sima Shakoorjavan, Dawid Stawski, Somaye Akbari

Abstract:

In this study, great attempts have been made to initially modify polylactide (PLA) nonwoven surface with poly(amidoamine) (PAMMA) dendritic polymer to create amine active sites on PLA surface through aminolysis reaction. Further, layer-by-layer deposition of four layers of two weak polyelectrolytes, including PAMAM as polycation and polyacrylic acid (PAA) as polyanion on activated PLA, was monitored with turbidity analysis of waste-polyelectrolytes after each deposition step. The FTIR-ATR analysis confirmed the successful introduction of amine groups into PLA polymeric chains through the emerging peak around 1650 cm⁻¹ corresponding to N-H bending vibration and a double wide peak at around 3670-3170 cm⁻¹ corresponding to N-H stretching vibration. The adsorption-desorption behavior of (PAMAM) and poly (PAA) deposition was monitored by turbidity test. Turbidity results showed the desorption and removal of the previously deposited layer (second and third layers) upon the desorption of the next layers (third and fourth layers). Also, the importance of proper rinsing after aminolysis of PLA nonwoven fabric was revealed by turbidity test. Regarding the sample with insufficient rinsing process, higher desorption and removal of ungrafted PAMAM from aminolyzed-PLA surface into PAA solution was detected upon the deposition of the first PAA layer. This phenomenon can be due to electrostatic attraction between polycation (PAMAM) and polyanion (PAA). Moreover, the successful layer deposition through LBL was confirmed by the staining test of acid red 1 through spectrophotometry analysis. According to the results, layered PLA with four layers with PAMAM as the top layer showed higher dye absorption (46.7%) than neat (1.2%) and aminolyzed PLA (21.7%). In conclusion, the complicated adsorption-desorption behavior of dendritic polycation and linear polyanion systems was observed. Although desorption and removal of previously adsorbed layers occurred upon the deposition of the next layer, the remaining polyelectrolyte on the substrate is sufficient for the adsorption of the next polyelectrolyte through electrostatic attraction between oppositely charged polyelectrolytes. Also, an increase in dye adsorption confirmed more introduction of PAMAM onto PLA surface through LBL.

Keywords: surface modification, layer-by-layer technique, weak polyelectrolytes, adsorption-desorption behavior

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Authors: Matej Komanec, Tomas Nemecek, Dmytro Suslov, Petr Chvojka, Stanislav Zvanovec

Abstract:

Nonlinear phenomena in the near- and mid-infrared region are attracting scientific attention mainly due to the supercontinuum generation possibilities and subsequent utilizations for ultra-wideband applications like e.g. absorption spectroscopy or optical coherence tomography. Thulium-based fiber lasers provide access to high-power ultrashort pump pulses in the vicinity of 2000 nm, which can be easily exploited for various nonlinear applications. The paper presents a simulation and experimental study of a pulsed thulium laser based for near-infrared (NIR) and mid-infrared (MIR) nonlinear applications in specialty optical fibers. In the first part of the paper the thulium laser is discussed. The thulium laser is based on a gain-switched seed-laser and a series of amplification stages for obtaining output peak powers in the order of kilowatts for pulses shorter than 200 ps in full-width at half-maximum. The pulsed thulium laser is first studied in a simulation software, focusing on seed-laser properties. Afterward, a pre-amplification thulium-based stage is discussed, with the focus of low-noise signal amplification, high signal gain and eliminating pulse distortions during pulse propagation in the gain medium. Following the pre-amplification stage a second gain stage is evaluated with incorporating a thulium-fiber of shorter length with increased rare-earth dopant ratio. Last a power-booster stage is analyzed, where the peak power of kilowatts should be achieved. Examples of analytical study are further validated by the experimental campaign. The simulation model is further corrected based on real components – parameters such as real insertion-losses, cross-talks, polarization dependencies, etc. are included. The second part of the paper evaluates the utilization of nonlinear phenomena, their specific features at the vicinity of 2000 nm, compared to e.g. 1550 nm, and presents supercontinuum modelling, based on the thulium laser pulsed output. Supercontinuum generation simulation is performed and provides reasonably accurate results, once fiber dispersion profile is precisely defined and fiber nonlinearity is known, furthermore input pulse shape and peak power must be known, which is assured thanks to the experimental measurement of the studied thulium pulsed laser. The supercontinuum simulation model is put in relation to designed and characterized specialty optical fibers, which are discussed in the third part of the paper. The focus is placed on silica and mainly on non-silica fibers (fluoride, chalcogenide, lead-silicate) in their conventional, microstructured or tapered variants. Parameters such as dispersion profile and nonlinearity of exploited fibers were characterized either with an accurate model, developed in COMSOL software or by direct experimental measurement to achieve even higher precision. The paper then combines all three studied topics and presents a possible application of such a thulium pulsed laser system working with specialty optical fibers.

Keywords: nonlinear phenomena, specialty optical fibers, supercontinuum generation, thulium laser

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Authors: Fatemeh Rouhi, Hadi Nassiri

Abstract:

Earning forecast is a key element in economic decisions but there are some situations, such as conflicts of interest in financial reporting, complexity and lack of direct access to information has led to the phenomenon of information asymmetry among individuals within the organization and external investors and creditors that appear. The adverse selection and moral hazard in the investor's decision and allows direct assessment of the difficulties associated with data by users makes. In this regard, the role of trustees in corporate governance disclosure is crystallized that includes controls and procedures to ensure the lack of movement in the interests of the company's management and move in the direction of maximizing shareholder and company value. Therefore, the earning forecast of companies in the capital market and the need to identify factors influencing this study was an attempt to make relationship between moral hazard and corporate governance with earning forecast quality companies operating in the capital market and its impact on Earnings Forecasts quality by the company to be established. Getting inspiring from the theoretical basis of research, two main hypotheses and sub-hypotheses are presented in this study, which have been examined on the basis of available models, and with the use of Panel-Data method, and at the end, the conclusion has been made at the assurance level of 95% according to the meaningfulness of the model and each independent variable. In examining the models, firstly, Chow Test was used to specify either Panel Data method should be used or Pooled method. Following that Housman Test was applied to make use of Random Effects or Fixed Effects. Findings of the study show because most of the variables are positively associated with moral hazard with earnings forecasts quality, with increasing moral hazard, earning forecast quality companies listed on the Tehran Stock Exchange is increasing. Among the variables related to corporate governance, board independence variables have a significant relationship with earnings forecast accuracy and earnings forecast bias but the relationship between board size and earnings forecast quality is not statistically significant.

Keywords: corporate governance, earning forecast quality, moral hazard, financial sciences

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Authors: Mohammad Anwarul Kabir, Fayezul Islam

Abstract:

Language invariably is learned / taught to be used primarily as means of communications. Teaching a language for its native audience differs from teaching it to non-native audience. Moreover, teaching a language for communication only is different from teaching it for specific purposes. Arabic language is primarily regarded as the language of the Quran and the Sunnah (Prophetic tradition). Arabic is, therefore, learnt and spread all over the globe. However, Arabic is also a cultural heritage shared by all Islamic nations which has used Arabic for a long period to record the contributions of Muslim thinkers made in the field of wide spectrum of knowledge and scholarship. That is why the phenomenon of teaching Arabic by different educational institutes became quite rife, and the idea of teaching Arabic for specific purposes is heavily discussed in the academic sphere. Although the number of learners of Arabic is increasing consistently, yet their purposes vary. These include religious purpose, international trade, diplomatic purpose, better livelihood in the Arab world extra. By virtue of this high demand for learning Arabic, numerous institutes have been established all over the world including Bangladesh. This paper aims at focusing on the current status of the language institutes which has been established for learning Arabic for specific purposes in Bangladesh including teaching methodology, curriculum, and teachers’ quality. Such curricula and using its materials resulted in a lot of problems. The least, it confused teachers and students as well. Islamic educationalists have been working hard to professionally meet the need. They are following a systematic approach of stating clear and achievable goals, building suitable content, and applying new technology to present these learning experiences and evaluate them. It also suggests a model for designing instructional systems that responds to the need of non-Arabic speaking Islamic communities and provide the knowledge needed in both linguistic and cultural aspects. It also puts forward a number of suggestions for the improvement of the teaching / learning Arabic for specific purposes in Bangladesh after a detailed investigation in the following areas: curriculum, teachers’ skills, method of teaching and assessment policy.

Keywords: communication, Quran, sunnah, educational institutes, specific purposes, curriculum, method of teaching

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Authors: Kayode Oshinubi, Brice Kammegne, Jacques Demongeot

Abstract:

The use of mathematical tools like Partial Differential Equations and Ordinary Differential Equations have become very important to predict the evolution of a viral disease in a population in order to take preventive and curative measures. In December 2019, a novel variety of Coronavirus (SARS-CoV-2) was identified in Wuhan, Hubei Province, China causing a severe and potentially fatal respiratory syndrome, i.e., COVID-19. Since then, it has become a pandemic declared by World Health Organization (WHO) on March 11, 2020 which has spread around the globe. A reaction-diffusion system is a mathematical model that describes the evolution of a phenomenon subjected to two processes: a reaction process in which different substances are transformed, and a diffusion process that causes a distribution in space. This article provides a mathematical study of the Susceptible, Exposed, Infected, Recovered, and Vaccinated population model of the COVID-19 pandemic by the bias of reaction-diffusion equations. Both local and global asymptotic stability conditions for disease-free and endemic equilibria are determined using the Lyapunov function are considered and the endemic equilibrium point exists and is stable if it satisfies Routh–Hurwitz criteria. Also, adequate conditions for the existence and uniqueness of the solution of the model have been proved. We showed the spatial distribution of the model compartments when the basic reproduction rate $\mathcal{R}_0 < 1$ and $\mathcal{R}_0 > 1$ and sensitivity analysis is performed in order to determine the most sensitive parameters in the proposed model. We demonstrate the model's effectiveness by performing numerical simulations. We investigate the impact of vaccination and the significance of spatial distribution parameters in the spread of COVID-19. The findings indicate that reducing contact with an infected person and increasing the proportion of susceptible people who receive high-efficacy vaccination will lessen the burden of COVID-19 in the population. To the public health policymakers, we offered a better understanding of the COVID-19 management.

Keywords: COVID-19, SEIRV epidemic model, reaction-diffusion equation, basic reproduction number, vaccination, spatial distribution

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Authors: Sima Cheraghi Dehdezi, Nasser Hamdami

Abstract:

Air-drying is the most widely employed method for preserving fruits and vegetables. Most of the dried products must be rehydrated by immersion in water prior to their use, so the study of rehydration kinetics in order to optimize rehydration phenomenon has great importance. Rehydration typically composes of three simultaneous processes: the imbibition of water into dried material, the swelling of the rehydrated products and the leaching of soluble solids to rehydration medium. In this research, squash (Cucurbita pepo) fruits were cut into 0.4 cm thick and 4 cm diameter slices. Then, squash slices were blanched in a steam chamber for 4 min. After cooling to room temperature, squash slices were dehydrated in a hot air dryer, under air flow 1.5 m/s and air temperature of 60°C up to moisture content of 0.1065 kg H2O per kg d.m. Dehydrated samples were kept in polyethylene bags and stored at 4°C. Squash slices with specified weight were rehydrated by immersion in distilled water at different temperatures (25, 50, and 75°C), various dry matter-water ratios (1:25, 1:50, and 1:100), which was agitated at 100 rpm. At specified time intervals, up to 300 min, the squash samples were removed from the water, and the weight, moisture content and rehydration indices of the sample were determined.The texture characteristics were examined over a 180 min period. The results showed that rehydration time and temperature had significant effects on moisture content, water absorption capacity (WAC), dry matter holding capacity (DHC), rehydration ability (RA), maximum force and stress in dried squash slices. Dry matter-water ratio had significant effect (p˂0.01) on all squash slice properties except DHC. Moisture content, WAC and RA of squash slices increased, whereas DHC and texture firmness (maximum force and stress) decreased with rehydration time. The maximum moisture content, WAC and RA and the minimum DHC, force and stress, were observed in squash slices rehydrated into 75°C water. The lowest moisture content, WAC and RA and the highest DHC, force and stress, were observed in squash slices immersed in water at 1:100 dry matter-water ratio. In general, for all rehydration conditions of squash slices, the highest water absorption rate occurred during the first minutes of process. Then, this rate decreased. The highest rehydration rate and amount of water absorption occurred in 75°C.

Keywords: dry matter-water ratio, squash, maximum force, rehydration ability

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Authors: Varvara Roubtsova, Mohamed Chekired

Abstract:

Recent studies on the numerical simulation of geotechnical problems show the importance of considering the soil micro-structure. At this scale, soil is a discrete particle medium where the particles can interact with each other and with water flow under external forces, structure loads or natural events. This paper presents research conducted in a virtual laboratory named SiGran, developed at IREQ (Institut de recherche d’Hydro-Quebec) for the purpose of investigating a broad range of problems encountered in geotechnics. Using Discrete Element Method (DEM), SiGran simulated granular materials directly by applying Newton’s laws to each particle. The water flow was simulated by using Marker and Cell method (MAC) to solve the full form of Navier-Stokes’s equation for non-compressible viscous liquid. In this paper, examples of numerical simulation and their comparisons with real experiments have been selected to show the complexity of geotechnical research at the micro level. These examples describe transient flows into a porous medium, interaction of particles in a viscous flow, compacting of saturated and unsaturated soils and the phenomenon of liquefaction under seismic load. They also provide an opportunity to present SiGran’s capacity to compute the distribution and evolution of energy by type (particle kinetic energy, particle internal elastic energy, energy dissipated by friction or as a result of viscous interaction into flow, and so on). This work also includes the first attempts to apply micro discrete results on a macro continuum level where the Smoothed Particle Hydrodynamics (SPH) method was used to resolve the system of governing equations. The material behavior equation is based on the results of simulations carried out at a micro level. The possibility of combining three methods (DEM, MAC and SPH) is discussed.

Keywords: discrete element method, marker and cell method, numerical simulation, multi-scale simulations, smoothed particle hydrodynamics

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Authors: Kuo-Wei Hsu, Wei-Chin Lo

Abstract:

In these years, urban agriculture development has been wide spreading all over the world. The development of urban agriculture is an evolution process of highly urbanization, as well as an agricultural phenomenon closely related to the development of economy, society and culture in urban areas. It provides densely populated areas with multi-functional uses of land, impacting strategic development of both large and small towns in the area. In addition, the participation of social enterprises keeps industrial competitiveness and makes gains when facing rapid transformation of industrial structures and new patterns of lifestyles in urban areas. They create better living conditions as well as protect the environment with innovative business beliefs, which give new ways for development of urban agriculture. Also, through building up the value chain, these social enterprises are capable of creating value for urban agriculture. Most of research regarding to social enterprises currently explore the relationship between corporate responsibilities and its role play, operational mode and performance and organizational patterns. Merely some of them discuss the function of social entrepreneurship in the development of urban agriculture. Moreover, none of them have explored the value creation for development of urban agriculture processed by social enterprises, as well as how social enterprises operate to increase competitive advantages, which make it possible to achieve industrial innovation, increase corporate value and even provide services with value creation. Therefore, this research mainly reviews current business patterns and operational conditions of social enterprises. This research endowed social responsibilities, and discusses current development process of urban agriculture. This research adopts Value Chain perspective to discuss key factors for value creation with respect to the development of urban agriculture processed by social enterprises. Thereby after organization and integration this research develops the prospect of value creation referring to urban agriculture processed by social enterprises and builds the value chain for urban agriculture. In conclusion, this research explored the relationship between value chain and value creation, which relates to values of customer, enterprise, society and economy referring to the development of urban agriculture uniquely, in consideration of the participation of social enterprises, and hence built the connection between value chain and value creation in the development of urban agriculture by social enterprises. The research found, social enterprises help to enhance the connection between the enterprise value and society value, mold corporate image with social responsibility and create brand value, and therefore impact the increase of economic value.

Keywords: urban agriculture development, value chain, social enterprise, urban systems

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Authors: F. Mohammadsadeghi

Abstract:

Relevance of research: Axial compressors are used in both aircraft engine construction and ground-based gas turbine engines. The compressor is considered to be one of the main gas turbine engine units, which define absolute and relative indicators of engine in general. Failure of compressor often leads to drastic consequences. Therefore, safe (stable) operation must be maintained when using axial compressor. Currently, we can observe a tendency of increase of power unit, productivity, circumferential velocity and compression ratio of axial compressors in gas turbine engines of aircraft and ground-based application whereas metal consumption of their structure tends to fall. This causes the increase of dynamic loads as well as danger of damage of high load compressor or engine structure elements in general due to transient processes. In operating practices of aeronautical engineering and ground units with gas turbine drive the operational stability failure of gas turbine engines is one of relatively often failure causes what can lead to emergency situations. Surge occurrence is considered to be an absolute buckling failure. This is one of the most dangerous and often occurring types of instability. However detailed were the researches of this phenomenon the development of measures for surge before-the-fact prevention is still relevant. This is why the research of transient processes for axial compressors is necessary in order to provide efficient, stable and secure operation. The paper addresses the problem of automatic control system improvement by integrating the anti-surge algorithms for axial compressor of aircraft gas turbine engine. Paper considers dynamic exhaustion of gas dynamic stability of compressor stage, results of numerical simulation of airflow flowing through the airfoil at design and stalling modes, experimental researches to form the criteria that identify the compressor state at pre-surge mode detection. Authors formulated basic ways for developing surge preventing systems, i.e. forming the algorithms that allow detecting the surge origination and the systems that implement the proposed algorithms.

Keywords: axial compressor, rotation stall, Surg, unstable operation of gas turbine engine

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Authors: Vishal Mahale, Jayashree Bijwe, Sujeet K. Sinha

Abstract:

Range of thermal conductivity (TC) of Friction Materials (FMs) is a critical issue since lower TC leads to accumulation of frictional heat on the working surface, which results in excessive fade while higher TC leads to excessive heat flow towards back-plate resulting in boiling of brake-fluid leading to ‘spongy brakes’. This phenomenon prohibits braking action, which is most undesirable. Therefore, TC of the FMs across the brake pads should not be high while along the brake pad, it should be high. To enhance TC, metals in the forms of powder and fibers are used in the FMs. Apart from TC improvement, metals provide strength and structural integrity to the composites. Due to higher TC Copper (Cu) powder/fiber is a most preferred metallic ingredient in FM industry. However, Cu powders/fibers are responsible for metallic wear debris generation, which has harmful effects on aquatic organisms. Hence to get rid of a problem of metallic wear debris generation and to keep the positive effect of TC improvement, incorporation of Cu fabric in NAO brake-pads can be an innovative solution. Keeping this in view, two realistic multi-ingredient FM composites with identical formulations were developed in the form of brake-pads. Out of which one composite series consisted of a single layer of Cu fabric in the body of brake-pad and designated as C1 while double layer of Cu fabric was incorporated in another brake-pad series with designation of C2. Distance of Cu fabric layer from the back-plate was kept constant for C1 and C2. One more composite (C0) was developed without Cu fabric for the sake of comparison. Developed composites were characterized for physical properties. Tribological performance was evaluated on full scale inertia dynamometer by following JASO C 406 testing standard. It was concluded that Cu fabric successfully improved fade resistance by increasing conductivity of the composite and also showed slight improvement in wear resistance. Worn surfaces of pads and disc were analyzed by SEM and EDAX to study wear mechanism.

Keywords: brake inertia dynamometer, copper fabric, non-asbestos organic (NAO) friction materials, thermal conductivity enhancement

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Authors: N. Elgendy, N. Hussein

Abstract:

The current Syrian crisis has caused unprecedented practices of global mobility. The process of forced eviction and the resettlement of refugees could be seen through the insights of the “new mobilities paradigm”. The mobility of refugees in terms of meaning and practice is a subject that calls for further studies. There is a need for the development of an approach to human mobility to understand a practice that is turning into a phenomenon in the 21^st century. This paper aims at studying, from a qualitative point of view, the process of movement within the six constituents of mobility defined as the first phase of the journey of a refugee. The second phase would include the process of settling in and re-defining the host country as new “home” to refugees. The change in the refugee state of mind and crossing the physical and mental borders from a “foreigner” to a citizen is encouraged by both the governmental policies and the local communities’ efforts to embrace these newcomers. The paper would focus on these policies of social and economic integration. The concept of integration connotes the idea that refugees would enjoy the opportunities, rights and services available to the citizens of the refugee’s new community. So, this paper examines this concept through showcasing the two hosting countries of Canada and Egypt, as they provide two contrasting situations in terms of cultural, geographical, economic and political backgrounds. The analysis would highlight the specific policies defined towards the refugees including the mass communication, media calls, and access to employment. This research is part of a qualitative research project on the process of Urban Mobility practiced by the Syrian Refugees, drawing on conversational interviews with new-settlers who have moved to the different hosting countries, from their home in Syria. It explores these immigrants’ practical and emotional relationships with the process of movement and settlement. It uses the conversational interviews as a tool to document analysis and draw relationships in an attempt to establish an understanding of the factors that contribute to the new-settlers feeling of home and integration within the new community.

Keywords: integration, mobility, policy, refugees

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Authors: Pamela Chia, Tay Yoong Chuan

Abstract:

Introduction: Severe pulmonary hypertension (PH) patients requiring non-cardiac surgery risk have increased mortality rates ranging. These patients are plagued with cardiorespiratory failure, dysrhythmias and anticoagulation potentially with concurrent sepsis and renal insufficiency, perioperative morbidity. We present a deaf-mute patient with severe idiopathic PH emergently prepared for ruptured ectopic laparotomy. Case Report: A 20 year-old female, 62kg (BMI 25 kg/m2) with severe idiopathic PH (2DE Ejection Fraction was 41%, Pulmonary Artery Systolic Pressure (PASP) 105 mmHg, Right ventricle strain and hypertrophy) and selective mutism was rushed in for emergency laparotomy after presenting to the emergency department for abdominal pain. The patient had an NYHA Class II with room air SpO2 93-95%. While awaiting lung transplant, the patient takes warfarin, Sildanefil, Macitentan and even Selexipag for rising PASP. At presentation, vital signs: BP 95/63, HR 119 SpO2 88% (room air). Despite decreasing haemoglobin 14 to 10g/dL, INR 2.59 was reversed with prothrombin concentrate, and Vitamin K. ECG revealed Right Bundle Branch Block with right ventricular strain and x-ray showed cardiomegaly, dilated Right Ventricle, Pulmonary Arteries, basal atelectasis. Arterial blood gas showed compensated metabolic acidosis pH 7.4 pCO2 32 pO2 53 HCO3 20 BE -4 SaO2 88%. The cardiothoracic surgeon concluded no role for Extracorporeal Membrane Oxygenation (ECMO). We inserted invasive arterial and central venous lines with blood transfusion via an 18G cannula before the patient underwent a midline laparotomy, haemostasis of ruptured ovarian cyst with 2.4L of clots under general anesthesia and FloTrac cardiac output monitoring. Rapid sequence induction was done with Midazolam/Propofol, remifentanil infusion, and rocuronium. The patient was maintained on Desflurane. Blood products and colloids were transfused for further 1.5L blood loss. Postoperatively, the patient was transferred to the intensive care unit and was extubated uneventfully 7hours later. The patient went home a week later. Discussion: Emergency hemostasis laparotomy in anticoagulated WHO Class I PH patient awaiting lung transplant with no ECMO backup poses tremendous stress on the deaf-mute patient and the anesthesiologist. Balancing hemodynamics avoiding hypotension while awaiting hemostasis in the presence of pulmonary arterial dilators and anticoagulation requires close titration of volatiles, which decreases RV contractility. We review the contraindicated anesthetic agents (ketamine, N2O), choice of vasopressors in hypotension to maintain Aortic-right ventricular pressure gradients and nitric oxide use perioperatively. Conclusion: Interdisciplinary communication with a deaf-mute moribund patient and anesthesia considerations pose many rare challenges worth sharing.

Keywords: pulmonary hypertension, case report, warfarin reversal, emergency surgery

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Authors: Aaron G. Laylo

Abstract:

This paper mainly assumes that social entrepreneurship contributes significantly to youth empowerment i.e., work and community engagement. Two questions are thus raised in order to establish this hypothesis: 1) First, how does social entrepreneurship contribute to youth empowerment?; and 2) secondly, why is social entrpreneurship significantly incremental to youth empowerment? This research aims a) to investigate on the social aspect of entrepreneurship; b) to explore challenges in youth empowerment particularly in respect to work and community engagement; and c) to inquire into whether social enterprises have truly served as a catalyst for, thus an effective response to, youth empowerment. It must be emphasized that young people, which comprise 1.8 billion in a world of seven billion are an asset; Apparently, how to maximize that potential is crucial. By utilizing exploratory research design, the paper endeavors to generate new ideas in regards to both components, develop tentative theories on social entrepreneurship, and refine certain issues that are under observation and seek scholarly attention— a rather emerging phenomenon vis a vis the challenge to empower a significant cluster of the society. Case studies will be utilized as an approach in order to comparatively analyze youth-driven social enterprises in the Philippines that have been widely recognized as successful insofar as social impact is concerned. As most scholars attested, social entrepreneurship is still at its infancy stage. Youth empowerment, meanwhile, is yet a vast area to explore insofar as academic research is concerned. Programs and projects that advocate the pursuit of these components abound. However, academic research is yet to be undertaken to see and understand their social and economic relevance. This research is also an opportunity for scholars to explore, understand, and make sense of the promise that lies in social entrepreneurship research and how it can serve as a catalyst for youth empowerment. Youth-driven social enterprises can be an influential tool in sustaining development across the globe as they intend to provide opportunities for optimal economic productivity that recognizes social inclusion. Ultimately, this study should be able to contribute to both research and development-in-practice communities for the greater good of the society. By establishing the nexus between these two components, the research may contribute to fostering greater exploration of the benefits that both may yield to human progress as well as the gaps that have to be filled in by various policy stakeholders relevant to these units.

Keywords: social entpreneurship, youth, empowerment, social inclusion

Procedia PDF Downloads 305