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To suppress the adverse effect of the gear windage phenomenon in the high-speed aeronautic industry, a shroud as an effective alternative strategy is usually to enclose gears to reduce the windage behaviors of high-speed gears. To deeply understand these no-load power losses, this paper proposes a new simulation methodology based on the Lattice Boltzmann method to study the windage losses of a shrouded spur gear and conducts a series of numerical studies. The models reproduce a shroud spur gear varying radial and axial clearances to evaluate the influence of casing walls on windage losses. The simulation results were then compared with experimental values, showing a satisfactory agreement. Furthermore, a torque containment factor integrating the air compressibility at high Mach numbers is introduced to represent the reduction in torque (windage power losses) for the shrouded gear compared to the free case, and the theoretical formulae for predicting windage power losses are further improved for better applicability as the tight shroud approaches the gear during the preliminary design stage. [ABSTRACT FROM AUTHOR]

To suppress the adverse effect of the gear windage phenomenon in the high-speed aeronautic industry, a shroud as an effective alternative strategy is usually to enclose gears to reduce the windage behaviors of high-speed gears. To deeply understand these no-load power losses, this paper proposes a new simulation methodology based on the Lattice Boltzmann method to study the windage losses of a shrouded spur gear and conducts a series of numerical studies. The models reproduce a shroud spur gear varying radial and axial clearances to evaluate the influence of casing walls on windage losses. The simulation results were then compared with experimental values, showing a satisfactory agreement. Furthermore, a torque containment factor integrating the air compressibility at high Mach numbers is introduced to represent the reduction in torque (windage power losses) for the shrouded gear compared to the free case, and the theoretical formulae for predicting windage power losses are further improved for better applicability as the tight shroud approaches the gear during the preliminary design stage.

The cooling fan is one of the important noise sources for new energy vehicles, and the research on its aerodynamic and aeroacoustic characteristics is of great help to improve the noise, vibration and harshness performance of new energy vehicles. However, most of these studies focus on the impeller, and little consideration has been given to the study of the shroud. Based on the coupling calculation method of large eddy simulation and the Ffowcs-Williams and Hawkings acoustics model, the aerodynamic and aeroacoustic characteristics in a cooling fan with the shroud are investigated at flow rates from 0.623 kg/s to 1.019 kg/s (where 0.865 kg/s is the flow rate corresponding to the best efficiency point). The accuracy of numerical simulation results is verified by the grid independence verification and the comparison of experimental data. Research shows that several large-scale vortex structures are observed in the clearance between the impeller and the shroud. The maximum peak-to-peak values of pressure fluctuation at different flow rates occur in the intermediate section or outlet section of the shroud. Although the shroud contributes relatively less to the far field noise, its different distribution may change the position of the maximum sound pressure level. The dominant frequency of pressure fluctuation equals the blade passage frequency (BPF) and the maximum SPL is around the BPF, both of which are independent of flow rates. The maximum SPL and the amplitude of the dominant frequency decrease as the flow rate increases. [ABSTRACT FROM AUTHOR]

Abstract In recent urban buildings, there is an interest in using wind turbines inside the buildings. Thus, the rotors of wind turbines are shrouded by the walls of the buildings. A design for using wind turbines in urban areas is to use shrouded turbines on the roof of a building. Since vertical axis wind turbines (VAWTs) with low environmental impacts are recommended for energy supply in urban areas, here, the interaction of two shrouded VAWTs has been studied numerically. Based on the effects of different shroud parts, the diffuser‐shrouded turbines are selected. The arrangement of diffuser‐shrouded VAWTs has been optimized using the response surface method optimization with the Kriging model. The optimization samples are chosen by the design of experiment method to reduce the number of simulations and increase optimization accuracy. The total power coefficient of the optimized cluster is 46.2% higher than the sum of the same individual diffuser‐shrouded turbines and 149.6% higher than the sum of individual bare VAWTs. The economic assessment shows that the levelized cost of energy of the optimized cluster of two diffuser‐shrouded VAWTs is reduced by about 40% compared to two bare VAWTs.

This research aims to analyze the performance of hydrokinetic turbines under yaw misalignment conditions using descriptive statistical methods on coefficient of power (Cp) data. Tests were conducted at water velocities of 0.7, 0.9, and 1.1 m/s for three types of turbine shrouds consisting of turbines without shrouds, turbines with two different types of shrouds, at yaw angles from 0° to 25° with 5° intervals. The study concludes that the performance of each turbine type is significantly influenced by the combination of water flow velocity and yaw angle. The diffuser type has the highest Cp value at every yaw angle, but its performance decreases with increasing yaw angle. The Blade type has poorer performance compared to the diffuser at every yaw angle and has the best performance at a combination of 1.1 m/s velocity and 5° yaw angle. Meanwhile, the shroud type has more stable performance and is not greatly affected by variations in velocity and yaw angle. Based on the analysis of changes in average Cp values with changes in yaw angle at V 0.7 m/s, all three turbine types experienced an increase in Cp value at a yaw angle of 5, with the shroud experiencing the most significant increase. At V 0.9 m/s, the diffuser and shroud types were able to maintain their average Cp values at every yaw angle, while the blade type decreased with increasing yaw angle and experienced a significant decrease at a yaw angle of 25. At V 1.1 m/s, the diffuser and blade types experienced a decrease in performance with every increase in yaw angle, but the shroud type was able to maintain the same Cp value and even experienced a significant increase at a yaw angle of 5.

In recent urban buildings, there is an interest in using wind turbines inside the buildings. Thus, the rotors of wind turbines are shrouded by the walls of the buildings. A design for using wind turbines in urban areas is to use shrouded turbines on the roof of a building. Since vertical axis wind turbines (VAWTs) with low environmental impacts are recommended for energy supply in urban areas, here, the interaction of two shrouded VAWTs has been studied numerically. Based on the effects of different shroud parts, the diffuser‐shrouded turbines are selected. The arrangement of diffuser‐shrouded VAWTs has been optimized using the response surface method optimization with the Kriging model. The optimization samples are chosen by the design of experiment method to reduce the number of simulations and increase optimization accuracy. The total power coefficient of the optimized cluster is 46.2% higher than the sum of the same individual diffuser‐shrouded turbines and 149.6% higher than the sum of individual bare VAWTs. The economic assessment shows that the levelized cost of energy of the optimized cluster of two diffuser‐shrouded VAWTs is reduced by about 40% compared to two bare VAWTs. [ABSTRACT FROM AUTHOR]

The Cycle of services of Novgorod Cathedral of the Holy Wisdom included singing services (ᾀσματική ἀκολουθία) after the practice of the Hagia Sophia in Constantinople. Its description is known since the 13th century from the Novgorod liturgical manuscripts. Since the end of 15th century the double-sided proskynesis icons has been an important integral part of singing service in Novgorod Cathedral. The unique complex of the images of the Saviour, Mother of God, saints, and the Bible scenes was created at this time. The complicated organization composition of the Novgorod series allowed to lay one icon in the church naos at festive day or to carry out all icons with images of saints to square near Cathedral during the rites of the New Year on September 1 and on Sunday of the Last Judgement. The icons replaced one another during the Holy Week. The Shroud with the embroidery image of dead Christ was carried out from altar and put on a table in the middle of naos at Holy Saturday. The icon Resurrection (Descent into Hell) replaced the Shroud at early morning of Resurrection Sunday. It was a real “mystery of images”. Богослужебный цикл в новгородском соборе Святой Софии включал знаменитые песенные последования (ᾀσματική ἀκολουθία) согласно Типикону Святой Софии в Константинополе. Их описания известны в новгородских литургических рукописях с XIII в. С конца XV в. важную роль в совершении песенных последований в Новгороде играли аналойные двусторонние иконы, уникальный комплекс которых с образами Спасителя, Богоматери, святых и библейских сюжетов был создан в это время. Организация серии позволяла как выкладывать на аналой в наосе храма в праздничный день одну икону, так и выносить иконы с образами святых на площадь близ Св. Софии в дни свершения действа Новолетия 1 сентября или в Неделю о Страшном суде. Иконы сменяли друг друга на аналое в Страстную седмицу. Плащаницу с шитым изображением мёртвого Христа выносили из алтаря на стол посредине наоса в Страстную Субботу, его сменяла икона «Воскресение (Сошествие во ад)» ранним утром Пасхального Воскресения. Это была подлинная «мистерия образов».

This research focuses on computational fluid dynamics modeling and experimental analysis of a shrouded wind turbine. A shroud turbine comprises a wind turbine with a flanged shroud encircling it for better wind energy utilization at low wind speed. The effects of diffuser shape and flange angle have been studied by performing flow field analysis in Ansys Fluent for better utilization and condensing of the shroud size. The CFD analysis shows that a cycloid diffuser shape gives 7% more velocity than a straight shape. In addition, the optimum flange angle for a cycloid diffuser is +10°, while compared with the normal flange angle, the optimal flange angle has increased velocity and power by 4.83% and 15%, respectively. This increment is due to the variation in the magnitude of vortex generation behind the flange. Besides, the performance of the proposed 3D, shrouded, and unshrouded wind turbines was numerically analyzed, and a prototype model for the proposed wind turbines was manufactured and tested. The simulation and experimental results agree and lay within the acceptable range. Compared with an unshrouded wind turbine with a similar swept area and wind speed, the shrouded wind turbine increased velocity and power by 1.58 and 5, respectively. This increase in speed and power makes the shrouded turbine suitable for application in low wind speed areas. Moreover, it can be helpful in sparsely populated off-grid areas to generate electricity by being mounted on rooftops.

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With the increasing speed of aviation gear, windage loss has been the main component of power loss. Reducing windage is of great significance to improving the transmission efficiency of aviation spiral bevel gear. Firstly, the calculation model of enclosed spiral bevel gear was established, and the basic physical mechanism of windage power loss was illustrated by numerical simulation, so as to obtain the mechanical and energy characteristics of windage loss. Then, the influence of the geometry and clearance parameters of the shroud on the windage loss was studied by orthogonal test, variance analysis and optimization design. The mechanism of the shroud to reduce the windage loss under the multi-factors was also studied, and their interaction was obtained. The results show that the tooth surface clearance, heel clearance and meshing opening are significant factors, and the most significant factor is the heel clearance. The non-significant factor is the interaction of each factor. The least significant factor is the toe clearance. In other words, the windage power loss can be reduced to the greatest extent by simultaneously reducing the meshing opening of the shroud and the clearance value between shroud and the surface of the gear. Finally, based on the mechanism of reducing windage loss of shroud, the optimization design principle affecting the structural performance of shroud is put forward, which provides theoretical guidance for the practical application of shroud in windage reduction engineering. [ABSTRACT FROM AUTHOR]

Featured Application: This study contributes to the design of mixed inflow turbines to improve their performance in internal combustion engines. The choice of blades for mixed turbines is to achieve the required deflection with minimal losses. In addition, it is necessary that the blade functions without a detachment in a wide area outside the nominal operating point of the machine. In the blade profile study, it is required to satisfy the conditions relating to fluid mechanics and those relating to the possibility of realization of construction. The work carried out presents the effect of the blade deviation angle on the geometric blade shape and the performance of the mixed inflow turbine on keeping the same rotor casing in order to improve its performances. It was remarked that the efficiency is proportional to the deviation angle's increase, but the rotor became heavy. It has been determined that the effect of the blade deviation angle on mixed inflow performances decreases dramatically starting from the angle −20° for a 100% of machine load. It was urged to avoid relying on angles greater than −20 as values for blade deviation angles. The study noted that the maximum obtained in the output work and power is related to the highest the efficiency for a specific optimum design case (−35° of deviation blade angle) due to the increase in the contact surface between the blade and the fluid, but the problem is that the rotor gets a little heavy (4.37% weight gain). Among recommendations, attention was given to the more significant absolute exit kinetic energies, for values of deviation blade angle between -10° and −20°, where an exhaust diffuser is recommended to use to recover a part of it into a greater expansion ratio. These simulation results were obtained using a CFD calculation code-named CFX.15. This code allowed for the resolution of the averaged dynamic equations governing the stationary, compressible, and viscous internal flow. [ABSTRACT FROM AUTHOR]

The shroud is a key component of the frost-free refrigerator and its geometric parameters have great influence on the aerodynamic performance of the whole system. Previous researches mainly focused on the effect of other components, such as the fan, shelves, or plate-evaporator. In this paper, the influence of the shroud with multi-outlets on the flow distributions of a frost-free refrigerator is studied thoroughly with the help of Computational Fluid Dynamics (CFD) tools. A 1/2 3-D CFD model is developed, where the verification of turbulence models and mesh independence tests are performed by comparing the mass flow rate obtained by different model configurations. The standard k-epsilon is deemed as the most suitable turbulence model choice and a mesh with Fine level is considered as mesh independence. To obtain the boundaries of the developed CFD model, an airflow velocity test rig is built and constructed. To convert the measured data to CFD model, Structural Response Vector (SRV) method is implemented for velocity profile fitting, and the fitted surface is assigned by User Defined Functions (UDF) macros in simulations. A series of simulations are carried out with the developed model, and the results indicates that no streamline in the middle two cavities of the original freezer compartment and the airflow velocities at the three outlets of the investigated shroud show a certain difference. To optimize the flow distribution, the agent model based on the BP neural network is established, in which four critical parameters of the shroud are adopted as design variables. The results show that the velocity streamlines in the middle two cavities are significantly increased after optimization and the value of the mean square error model constructed in optimization has a reduction of 61.09% compared with the original design.

This research focuses on computational fluid dynamics modeling and experimental analysis of a shrouded wind turbine. A shroud turbine comprises a wind turbine with a flanged shroud encircling it for better wind energy utili- zation at low wind speed. The effects of diffuser shape and flange angle have been studied by performing flow field analysis in Ansys Fluent for better utiliza- tion and condensing of the shroud size. The CFD analysis shows that a cycloid diffuser shape gives 7% more velocity than a straight shape. In addition, the optimum flange angle for a cycloid diffuser is +10°, while compared with the normal flange angle, the optimal flange angle has increased velocity and power by 4.83% and 15%, respectively. This increment is due to the variation in the magnitude of vortex generation behind the flange. Besides, the performance of the proposed 3D, shrouded, and unshrouded wind turbines was numerically analyzed, and a prototype model for the proposed wind turbines was manufac- tured and tested. The simulation and experimental results agree and lay within the acceptable range. Compared with an unshrouded wind turbine with a similar swept area and wind speed, the shrouded wind turbine increased velocity and power by 1.58 and 5, respectively. This increase in speed and power makes the shrouded turbine suitable for application in low wind speed areas. Moreover, it can be helpful in sparsely populated off-grid areas to generate electricity by being mounted on rooftops. [ABSTRACT FROM AUTHOR]

In the current study, effects of two different underhood geometry modifications namely; fan position relative to shroud and fan tip clearance, on airflow through an agricultural tractor engine cooling system are investigated by utilizing CFD modeling. For the characterization of each modification, the underhood components are reduced to a domain of cooling systems including only fan, shroud, and radiator that allows saving in computational time and cost. The models are validated using a custom designed underhood flow setup, where hotwire velocity measurements at proximity to the radiator are conducted. The mass flow rate and the uniformity of the airflow through the radiator are quantified as performance parameters. For the former modification, position of fan relative to shroud, the computations are performed for the percentages of fan projection into shroud (FPiS) varying from 78% to 0% at fan rotational speeds of 2060 and 2800 rpm. The optimum fan location is found to be around 56–60% for both rotational speeds that leads 8% increase in mass flow rate compared with the pre-design location of 74%. In addition, a noticeable reduction in the relative magnitude of the RMS velocity through the radiator is obtained for the moderate FPiS values. For the latter modification, fan tip clearance, the computations are performed for the tip clearance values varying from 5.25to 12 mm at a fan rotational speed of 2060 rpm. As the tip clearance decreases up to 6 mm, air mass flow rate can be improved by 7%. However, further reduction in tip clearance does not improve the air mass flow rate instead it decreases, suggesting an optimum tip clearance value. The results suggest that the proper geometrical modifications in engine cooling systems might induce significant improvement in the aforementioned performance indicators.

With the increasing speed of aviation gear, windage loss has been the main component of power loss. Reducing windage is of great significance to improving the transmission efficiency of aviation spiral bevel gear. Firstly, the calculation model of enclosed spiral bevel gear was established, and the basic physical mechanism of windage power loss was illustrated by numerical simulation, so as to obtain the mechanical and energy characteristics of windage loss. Then, the influence of the geometry and clearance parameters of the shroud on the windage loss was studied by orthogonal test, variance analysis and optimization design. The mechanism of the shroud to reduce the windage loss under the multi-factors was also studied, and their interaction was obtained. The results show that the tooth surface clearance, heel clearance and meshing opening are significant factors, and the most significant factor is the heel clearance. The non-significant factor is the interaction of each factor. The least significant factor is the toe clearance. In other words, the windage power loss can be reduced to the greatest extent by simultaneously reducing the meshing opening of the shroud and the clearance value between shroud and the surface of the gear. Finally, based on the mechanism of reducing windage loss of shroud, the optimization design principle affecting the structural performance of shroud is put forward, which provides theoretical guidance for the practical application of shroud in windage reduction engineering.

The choice of blades for mixed turbines is to achieve the required deflection with minimal losses. In addition, it is necessary that the blade functions without a detachment in a wide area outside the nominal operating point of the machine. In the blade profile study, it is required to satisfy the conditions relating to fluid mechanics and those relating to the possibility of realization of construction. The work carried out presents the effect of the blade deviation angle on the geometric blade shape and the performance of the mixed inflow turbine on keeping the same rotor casing in order to improve its performances. It was remarked that the efficiency is proportional to the deviation angle’s increase, but the rotor became heavy. It has been determined that the effect of the blade deviation angle on mixed inflow performances decreases dramatically starting from the angle −20° for a 100% of machine load. It was urged to avoid relying on angles greater than −20 as values for blade deviation angles. The study noted that the maximum obtained in the output work and power is related to the highest the efficiency for a specific optimum design case (−35° of deviation blade angle) due to the increase in the contact surface between the blade and the fluid, but the problem is that the rotor gets a little heavy (4.37% weight gain). Among recommendations, attention was given to the more significant absolute exit kinetic energies, for values of deviation blade angle between -10° and −20°, where an exhaust diffuser is recommended to use to recover a part of it into a greater expansion ratio. These simulation results were obtained using a CFD calculation code-named CFX.15. This code allowed for the resolution of the averaged dynamic equations governing the stationary, compressible, and viscous internal flow.

Nowadays, after more than twelve decades of studies involving many scientists from all over the world, we do not know the originary chemistry of the Shroud of Turin. This state of affairs is due to the uncertainty between two possibilities. The first one, deduced by Heller and Adler, asserts that the surface chemistry is linen cellulose structure. The two scientists have obtained this result by microanalysis of the samples extracted from the Linen of Turin. The second one, deduced by Rogers and subsequently studied with Arnoldi, supports the hypothesis that the linen threads were, in origin, covered with a thin layer of impurities. Also this result has been experimentally obtained. In fact, by microchemical tests, using iodine on thread pieces of the Shroud linen, it was detected the starch impurities presence. This study is an attempt to analyze the Rogers' hypothesis: a Maillard reaction between amines (nitrogen compound with a free -NH2 group), coming through the corpse wrapped in the Linen of Turin and reduced sugars, due to the manufacturing procedure, present on the surface of the above linen cloth. Therefore, as it has already affirmed, we have two different visions. However, we must take also into account that the second one hypothesis needs, at same time, the presence of amines and the absence of aromas and/or burial ointments. The aim of this our study is to see if the above hypothesis (the one of Rogers with Arnoldi) is able to yield on the linen a color distribution characterized by a I(z) correlation between the intensity of color and the cloth-body distance, as it occurs to the Shroud of Turin. [ABSTRACT FROM AUTHOR]

Based on Islamic era sources, inscribed robes were one of the valuable art works during the Ale-Buyid period that were gifted to courtiers in official ceremonies as a sign of honor for their loyalty. These robes normally contained the name of the ruler. In the Ale-Buyid period, a combination of both Shi'a and Iranian-Sasanian led to the creation of a new style of art. From the remains of that period, number of textiles with inscriptions was discovered from two enclosures of Broj-e Nagharekhane and Bibi Shahrbanu in Ray. According to archaeological reports, the scripted textiles were used as shrouds or to cover graves. The inscriptions are in both plain and ornamental Kufic styles and in most of the cases, beside its function to convey a massage, had decorative functions too. Based on 25 scripted textile pieces from Ale-Buyid period which mostly were discovered from Ray, this research attempts to reveal the meaning and also the literature sources of the inscriptions. The data has been collected through library studies. This research shows that the texts contain prayers, ethical massage and some poems from Arab poets from the first Hijri to the Ale-Buyid period. In some cases, embroidery has changed the shape of the letters to create a rhythmic pattern in the text and for this reason; the text is illegible or contains a visual or written error. This shows that writing was as important as its content. Most of the fabrics obtained based on the content were robes, and the content of the inscriptions often had an individual audience and a prayer sentence. [ABSTRACT FROM AUTHOR]

The shroud is a key component of the frost-free refrigerator and its geometric parameters have great influence on the aerodynamic performance of the whole system. Previous researches mainly focused on the effect of other components, such as the fan, shelves, or plate-evaporator. In this paper, the influence of the shroud with multi-outlets on the flow distributions of a frost-free refrigerator is studied thoroughly with the help of Computational Fluid Dynamics (CFD) tools. A 1/2 3-D CFD model is developed, where the verification of turbulence models and mesh independence tests are performed by comparing the mass flow rate obtained by different model configurations. The standard k-epsilon is deemed as the most suitable turbulence model choice and a mesh with Fine level is considered as mesh independence. To obtain the boundaries of the developed CFD model, an airflow velocity test rig is built and constructed. To convert the measured data to CFD model, Structural Response Vector (SRV) method is implemented for velocity profile fitting, and the fitted surface is assigned by User Defined Functions (UDF) macros in simulations. A series of simulations are carried out with the developed model, and the results indicates that no streamline in the middle two cavities of the original freezer compartment and the airflow velocities at the three outlets of the investigated shroud show a certain difference. To optimize the flow distribution, the agent model based on the BP neural network is established, in which four critical parameters of the shroud are adopted as design variables. The results show that the velocity streamlines in the middle two cavities are significantly increased after optimization and the value of the mean square error model constructed in optimization has a reduction of 61.09% compared with the original design. [ABSTRACT FROM AUTHOR]

Banville’s latest trilogy Eclipse, Shroud, and Ancient Light forms an interconnected web of narratives that aptly dramatizes Banville’s fictional investigation of subjectivity and otherness. The “other” in these narratives is consistently a female other on whom the narrators bestow a multitude of roles in their narcissist quests for authenticity. The “woman” is represented simultaneously as an enigma, the site of “truth”, the guarantor of the narrators’ authentic self, and the screen onto which the protagonists aim to inscribe their aesthetic signatures. This paper proposes to read these figurations in close relation with the theoretical undertone with which Banville engages throughout his philosophically imbued meta-fiction. It specifically addresses the way in which the figure of the “woman” becomes entangled with Paul de Man’s elaborations on the “ontological crisis” in Romanticism as well as Friedrich Nietzsche’s aesthetics of the “surface”. Banville’s fictional engagement with these thinkers, I claim, offers a way to read the narrators’ ethical failure with regards to the key female characters as an aesthetic critique of ideology.

To achieve higher efficiency and performance, a modern gas turbine withstands the extremely high thermal environment. In the turbine endwall passage, a high and non-uniform heat transfer appears due to various secondary flow. The purge flow injected through the upstream slot between the stationary and rotating pars can thermally protect the endwall surface by forming air film layer on it. However, since an excessive amount of purge flow reduce the system efficiency, it is needed to effectively inject the purge flow with a limited amount. Accordingly, in the present study, the effect of purge slot exit shape on the film cooling effectiveness (hereby FCE) of a shroud surface was discussed. As nondimensional design parameters of the purge slot, L/W s , R W /W s , and R L /W s were defined, representing the geometric features: the slot width (W s), the fillet radius at the windward side (R W) and fillet radius at the leeward side (R L) of slot exit, respectively. The measurement of the FCE was performed in a five-blade linear cascade rig using the PSP (Pressure sensitive paint) technique. The results showed that the FCE increased for wider slot width at a given blowing ratio condition. In addition, the fillet radius at the windward side (R W) has a negative effect on the FCE regardless of blowing ratio condition since the purge flow was easily disturbed by the accelerated mainstream injection. On the other hand, the Case 7 with the R W /W s = 0.9 showed 5.1 % of the improvement of FCE at a higher blowing ratio M = 0.25 compared with the Case 2 with R W /W s = 0, which represents the sharp edge at the windward side of the slot exit. • Film cooling of a gas turbine shroud was studied using pressure sensitive paint technique. • Effects of purge slot exit shape on the film cooling effectiveness were examined. • A narrower slot width was beneficial for higher film cooling effectiveness. • A fillet at the windward side has a negative effect on film cooling effectiveness. • Small radius filler at the leeward side induced higher film cooling effectiveness. [ABSTRACT FROM AUTHOR]

Radiocarbon dating and scanning electron microscopy analyses were used to determine the age and conservation state of a palm mat made with hard fibers and a cotton shroud found in a funerary bundle of Zimapán Hidalgo, México. The fibers were also treated with an innovative treatment of chitosan and polypropylene glycol. The treatment was analyzed with a scanning electron microscopy and radiocarbon dating was applied to the treated fibers. The radiocarbon dating showed dates of 1022 a 1206 cal d.C therefore the textiles are prehispanic, and the treated fibers showed an early date (72-418 cal d.C.). This difference could be explained from the reservoir effect in the marine organisms because the chitosan is obtained from the chitin of crustacean's exoskeletons. The analysis also showed that the treatment for the fibers was effective because the fibers gained consolidation, flexibilization and also microorganisms were killed and removed. [ABSTRACT FROM AUTHOR]

Titanium and its alloys are often used for corrosion protection because they are able to offer high chemical resistance against various corrosive media. In this paper, shrouded plasma spray technology was applied to produce titanium coatings. A solid shroud with an external shrouding gas was used to plasma spray titanium powder feedstock with aim of reducing the oxide content in the as-sprayed coatings. The titanium coatings were assessed by optical microscope, scanning electron microscopy, X-ray diffraction, LECO combustion method and Vickers microhardness testing. The results showed that the presence of the shroud and the external shrouding gas led to a dense microstructure with a low porosity in the plasma-sprayed titanium coatings. The oxygen and nitrogen contents in the titanium coating were kept at a low level due to the shielding effect of the shroud attachment and the external shrouding gas. The dominant phase in the shrouded titanium coatings was mainly composed of α-Ti phase, which was very similar to the titanium feedstock powders. The shrouded plasma-sprayed titanium coatings had a Vickers microhardness of 404.2 ± 103.2 HV. [ABSTRACT FROM AUTHOR]

Abstract An experimental study has been conducted to investigate the heat-transfer characteristics of blade tips and shrouds with and without unsteady wakes. Depending on the presence of unsteady wakes, the local heat/mass-transfer coefficients of the tip and shroud were measured using the naphthalene sublimation method. Wakes from unsteady blades were modeled as wakes generated from moving cylindrical rod bundles. Test conditions were set to a Reynolds number of 100,000, based on an inlet velocity of 11.4 m/s and the axial chord length. The Strouhal number was varied from 0 to 0.22. For the case without unsteady wakes ( St = 0), high heat/mass-transfer coefficients appeared in regions where various flow patterns, such as flow reattachment, swirling flow, and vortices, occurred. Unsteady wakes ( St = 0.22) made high turbulence intensity of the tip leakage flow, and flow patterns ranging from flow reattachment to tip leakage vortex in the tip and shroud were changed and dispersed in the presence of unsteady wakes, thus changing the heat/mass-transfer distributions in these areas. Due to the high thermal load on the tip and shroud under unsteady wake conditions, more detailed cooling designs must be considered, ranging from film cooling holes to the installation of additional structures on the blade tip, especially in the leading edge region and mid-region I of the tip, and the mid-region I and trailing edge region of the shroud. [ABSTRACT FROM AUTHOR]

Banville's latest trilogy Eclipse, Shroud, and Ancient Light forms an interconnected web of narratives that aptly dramatizes Banville's fictional investigation of subjectivity and otherness. The "other" in these narratives is consistently a female other on whom the narrators bestow a multitude of roles in their narcissist quests for authenticity. The "woman" is represented simultaneously as an enigma, the site of "truth", the guarantor of the narrators' authentic self, and the screen onto which the protagonists aim to inscribe their aesthetic signatures. This paper proposes to read these figurations in close relation with the theoretical undertone with which Banville engages throughout his philosophically imbued meta-fiction. It specifically addresses the way in which the figure of the "woman" becomes entangled with Paul de Man's elaborations on the "ontological crisis" in Romanticism as well as Friedrich Nietzsche's aesthetics of the "surface". Banville's fictional engagement with these thinkers, I claim, offers a way to read the narrators' ethical failure with regards to the key female characters as an aesthetic critique of ideology. [ABSTRACT FROM AUTHOR]

Reducing the energy consumption and improving the efficiency of high-speed transmission systems are increasingly common goals; the windage power loss is not negligible in these methods. In this work, the multi-reference frame (MRF) and periodic boundary conditions (PBC) based on the computational fluid dynamics (CFD) method were adopted to investigate the windage phenomena of a single face gear with and without a shroud, and the impact of the gear speed on the windage power loss was analyzed. Furthermore, the effects on the distribution of static pressure due to the distances between the shroud and the gear body in different directions, including the outer radius direction, the inner radius direction, and the addendum direction were investigated. The results indicate that the gear speed significantly affected the windage loss, as the higher the gear speed was, the greater the windage power loss. Additionally, the shroud could effectively reduce the windage power loss, where the optimal distance from the addendum to the shroud was not the minimum distance; however, for the distances from the shroud to the inner radius and the outer radius, the smaller the distance was, the smaller the windage loss. The results can provide a theoretical basis and technical reference for reducing the windage power loss of various face gear drives.

This paper is objected to bring out an unbiased and detailed hydraulic response study in pumps as turbines due to blade rounding, inner and outer shroud rounding of the impeller inlet through high quality measurements of macroscopic parameters. To begin with a theoretical model is proposed where the hydraulic losses are categorized as flow zone and no-flow zone types, while suitable assumptions are made to the shaft and runner (Euler) torque. Four centrifugal pumps having specific speed in the range of 19–54 rpm are selected for this 3-stage impeller rounding investigation. All pumps had backward vane impeller designs. The blade rounding showed greater reduction of flow zone losses compared to increase of runner torque resulting in an efficiency rise of 1–1.5%, while inner shrouds have shown evidence of decrease in losses but an inconsistent behavior of runner torque gains. The final rounding stage at the outer shrouds displayed traces of proof of non-flow zone hydraulic optimization. The consolidated rounding effects were compared to results of other researchers which again showed concurrence and consistency. The paper evokes a sentiment that the technique of fixed geometry optimizations of backward vane impeller has been saturated given that the maximum efficiency rise is only in the range of 1–2.5%., even though the total hydraulic losses constitute 25–30% of the total energy (head) since the achieved best efficiency after modification ranges between 65% and 75%. Therefore, the paper recommends a calibrated methodology to change the backward vane angle so that the inlet relative velocity aligns with the blade and the strong wakes are reduced, which could reduce losses by 5–10%. To conclude the paper pragmatically looks towards the limited scale of PAT application compared to pumping and proposes the study of rounding effects on pump operation to see if there is any positive alleviation of performance, which could have a greater benefit to industry and society. [ABSTRACT FROM AUTHOR]