Rib Type Research Articles

Fluid Flow and Heat Transfer in an Annulus With Ribs on the Rotating Inner Cylinder Surface

Abstract Numerical studies on heat transfer in Taylor-Couette-Poiseuille flow in a cylindrical annulus with ribs mounted on the rotating inner cylinder are presented. The present study focuses on two different types of ribs, namely, longitudinal ribs and helical ribs. Three-dimensional, steady, incompressible, turbulent fluid flow is solved using a semi-implicit method for pressure linked equations (SIMPLE) algorithm based finite volume method. The numerical solution method is validated using two sets of benchmark experimental data. Extensive numerical computations are carried out at various Reynolds numbers (2100 < Re < 2400) and modified Taylor numbers (30,000 < Tam < 90,000) for annulus with and without ribs. Ribs enhance the transport of heat and momentum by inducing more vorticity and turbulence in the flow. The overall performance is presented in terms of thermal performance factor (TPF), which takes in to account the heat transfer as well as pressure drop in the ribbed annulus. Helical ribs are found to offer superior thermal performance than its longitudinal counterpart.

Numerical Analysis of CW Raman Amplifier in Silicon-on-Insulator Nano-Waveguides

Numerical analysis of continuous wave (CW) on-off optical Raman gain in Silicon-On-insulator (SOI) nano-waveguides has been investigated. Two types of waveguide structures rib and strip waveguides have been incorporated. The waveguide structures have designed to be 220 nm in height. Three different widths of (350, 450, 1000) nm were studied. At telecommunication wavelength of 1550 nm, Raman amplification was calculated to be about 65 dB in rib SOI waveguide. The obtained Raman amplification is the heist reported value at relatively low pump power. High Raman gain amplification in SOI nano-waveguides presents an important step towards integrated on-chip optoelectronic devices.

Comparative and contrast study of Karbandie’s Masonry ribs brick arrangements

Abstract Karbandies’ masonry ribs construction technology is influenced by form and size, on one hand, and traditional architects’ creativity, on the other hand. Some of the exclusive characteristics of construction techniques of Kar-bandies’ ribs are revealed, after investigating and identifying of some of traditional construction ways of them, investigating contemporary studies conducted in the field and comparing the methods. The masonry ribs have been built in different forms over time and such different forms result in formation of different construction technologies. The masonry ribs’ form and size and the bricks’ arrangement way have direct effect on their construction process. The aim of the present paper is to determine construction technology of the masonry ribs used in different Karbandies. Hence, in line with achieving this goal, it also tries to investigate geometric arrangement of bricks in masonry ribs. The present study, for the first time, presents a comparative structure to study different implementation ways of Kar-bandies’ masonry ribs and reasons for similarities and differences among different samples. Moreover, the present study tries to draw implementation way of different types of ribs with the aid of 2D and 3D software and by doing library studies, field understandings and interviewing the related masters and then the collected data were studied, comparatively. Data-gathering of this research included library studies which included written, listening and visual methods of books, articles and dissertations. Interviewing traditional masters, who are expertise in the field, were used in the samples analysis. Then according to the master builders’ advice, structural form of karbandi ribs was modelled using three-dimensional software type. In this study karbandie’s masonry ribs were divided into three categories of radial brick vault, pitched brick vault and a combination of them based on their brick arrangement way. Investigation of the results indicated that the bricks due to their geometrical form and variety in shape can result in various combinations. Different factors including materials, centering, dimensions, bay size and other factors are influential in bricks arrangement of the ribs. ter builders’ advice, structural form of karbandi ribs was modelled using three-dimensional software type. In this study karbandie’s masonry ribs were divided into three categories of radial brick vault, pitched brick vault and a combination of them based on their brick arrangement way. Investigation of the results indicated that the bricks due to their geometrical form and variety in shape can result in various combinations. Different factors including materials, centering, dimensions, bay size and other factors are influential in bricks arrangement of the ribs.

Assessment of Thermal Performance of Non-Conventional Grooved Stepped Shoe Ribs by CFD Technique

In improvement of the thermal performance there is necessity of the heat transfer augmentation. Heat transfer enhancement can be achieved with enlarged or extended surface, impeded boundary level, augmentation in the turbulence etc. It is desired to keep the size of heat exchanger compact for better working conditions. In the proposed work, we made the Computational Fluid Dynamics (CFD) analysis of the non-conventional type of ribs. In this work the non-conventional Stepped grooved shoe shaped ribs were studied by changing its geometry parameters like rib height (15, 20,22mm), thickness of the rib (4, 5,10 mm), and the ratio between these entities. The numerical analysis was done to study change in rate of heat transfer and pressure drop. The effects of variation in staggered arrangements and truncation gap on thermal performance were also studied. It was observed that providing staggered arrangement with truncation gap of 20 mm gives the optimum value of thermal enhancement factor of 1.33.

Recognition and classification of protrusion features on thin-wall parts for mold flow analysis

Thin-wall plastic parts exist in many products and are frequently manufactured by injection molding. The inner surface of a thin-wall part has many functional and structural features, typically divided into depressions and protrusions. While recognition of protrusion features is important in mold flow analysis, this recognition is difficult owing to the complexity and variety of the designed shapes. The purpose of this study was to develop a method for the detection and classification of protrusion features on thin-wall plastic parts. In the proposed algorithm, the inner and outer faces of a part model were detected first. Auxiliary faces, including translational, wall, and bottom faces, were recognized next. With auxiliary faces available, protrusion faces can thus be recognized and grouped in accordance with their neighboring relationship. A feature classification algorithm was finally implemented to classify five types of protrusions, namely tubes, ribs, columns, polygon blocks, and irregular extrusions. A detailed description of the procedures in each step of the proposed algorithm is provided. Twelve CAD models and analysis results are also presented to demonstrate the feasibility of the proposed protrusion recognition algorithm.

Crushing behavior of circumferentially corrugated square tube with different cross inner ribs

Abstract In this paper, new designed circumferentially corrugated square tubes (CCSTs) with cosine and triangular corrugation cross-sectional profiles, respectively, are proposed for energy absorption. Three types of cross inner ribs, namely, crisscross, X shape and star shape, are introduced to induce the deformation of CCSTs. Quasi-static crushing test and finite element simulation were used to investigate the crushing performance of the CCSTs. The results showed that all triangular profile CCSTs can not deform stably, and only the crisscross inner rib can induce the cosine profile CCSTs to deform progressively. The performance of cosine profile CCSTs with crisscross inner rib (i.e., CTC_C) under different geometric parameters was therefore further studied. It was found that the CTC_C develops four different deformation modes, and the ordered progressive mode Ⅱ (OPM Ⅱ) showed better energy absorption efficiency than the other modes. Finally, a theoretical model based on Simplified Super Folding Element method was presented to predict the mean crushing force of CTC_C deforming with OPM Ⅱ. By comparing with the experimental and FE results, the theoretical model was proved to be very accurate.

Phenetic analysis of natural apricot populations in the Mountainous Dagestan for endocarp (stone) features

Background. Studying the intraspecies diversity of fruit crop wild relatives is one of the leading trends in botanical and genetic resource research associated with identification and utilization of the phenotypic potential of the population and species, the initial stage in plant breeding and introduction processes, and a prerequisite to solving a number of problems posed by the theory of microevolution, biosystematics and population biology. Currently, large tracts of wild apricot populations (Prunus armeniaca L. = Armeniaca vulgaris Lam.) have been preserved in Central Asia, China and Dagestan. The natural populations of apricot in the Mountainous Dagestan are spread along the valleys of the Avar Koysu, Andi Koysu, Kazikumukh Koysu and Kara Koysu rivers, at altitudes of 350–1500 m ASL, and (sporadically) over the southern slopes – up to 1900 m ASL. They prefer crushed limestone hillsides, where they form the so-called ‘apricot savannah’, rarely assembling into dense massifs. With this in mind, it seems theoretically and practically interesting to evaluate various forms in the diversity of natural apricot populations in the Mountainous Dagestan, with qualitative traits of their endocarp (stone) as a target.Materials and methods. To analyze the diversity of endocarp (stone) forms in natural apricot populations under the conditions of the Mountainous Dagestan, three model cenopopulations (CPs) were selected: in Gunibsky District, along the Kara Koysu (Lower Keger Vlg., 900–1200 m ASL) and Bagdakuli rivers (Salta Vlg., 900–1100 m ASL), and in Levashinsky District, along the Kazikumukh Koysu river (Burtanimakhi Vlg., 1000–1200 m ASL). Stones were collected along the slopes by using transect itineraries. Morphological description of endocarps was made for 328 trees according to 11 qualitative features by standard techniques.Results. A comparative analysis of natural apricot populations showed high variation in the size and shape of the endocarp. Five classes were identified for stone size; of these, the very small (37.8%) and small (37.5%) types had the highest percentage. There were seven types of the endocarp’s shape (rounded, ellipsoid, ovoid, oblong, prolate, teardrop-shaped, and semicordate). Ovoid or rounded shape was observed in an overwhelming majority of apricot trees: their share was 65.3% of the total diversity. Correlation analysis of the endocarp’s features revealed credible positive correlations between the traits (1) ‘keel height’ and ‘rib width’, and (2) ‘lateral rib type’ and ‘rib width’. Creditable negative correlations were found for the trait ‘keel pattern’ with ‘lateral rib type’ and ‘keel height’.

Influence of Test Configuration on Bond Strength of GFRP Bars

It is well-known that test configuration affects bond behaviour of steel reinforcement, but this effect has not yet been sufficiently quantified when using FRP reinforcement. This paper presents partial results from an ongoing experimental programme that deals with the bond strength of GFRP bars with concrete, with regards to the effect of the surface treatment of the rebars and test configuration. A modified beam test is presented in this study along with a pull-out test with an eccentric bar placement. The bond strength of GFRP reinforcement with sand-coated treatment using silica sand and ribbed type with milled ribs was tested. The sand-coated bars exhibit different bond behaviour compared to the ribbed ones due to different forces transfer from the reinforcement to the concrete. Thickness of the concrete cover layer also has a significant effect on the bond behaviour of the reinforcement.

Mallomonas gusakovii sp. nov. (Chrysophyceae, Synurales), a new species from Phu Quoc Island, Vietnam

Mallomonas gusakovii sp. nov. is described from Vietnam based on silica-scale morphology studied by means of transmission and scanning electron microscopy. This species belongs to section Quadratae and is characterized by large and broad scales of three types with an internal reticulation, V-shaped rib and a forward projecting wing. Different types of the V-shaped rib in taxa from section Quadratae are discussed. Scales of Mallomonas gusakovii were found only in two sites in Phu Quoc Island, Southern Vietnam.

Finite Element Analysis and Influence Factors of Flexural Behavior of HFRP Reinforced Concrete Beams

HFRP (Hybrid Fiber Reinforced Plastics) ribs are a new type of composite rib made of a mixture of two or more continuous reinforcing fibers. Since the HFRP ribs have a "pseudo-yield" phase similar to that of steel bars, the mechanical properties of HFRP reinforced concrete structures are quite different from those of single FRP reinforced concrete, and should be studied in depth. In this paper, the finite element analysis of the hybrid effect of HFRP bars and the flexural behaviour of HFRP reinforced concrete beams is carried out. The ANSYS finite element analysis software is used to simulate the bending test of carbon/glass HFRP reinforced concrete beams with three different hybrid ratios. The calculation results are compared with the experimental results, and the rationality of the finite element model is verified. On this basis, the influence of mixing ratio, reinforcement ratio and concrete strength on the deflection of concrete beams is further analysed.

Approaches to Nordifikation of High-Latitude Construction Engineering

The simple mechanical transfer of structural technologies to high-latitude construction engineering is not efficient. But construction engineering nordifikation seems to be effective and expedient, for example working camps. Severe, extreme conditions in the Arctic are similar to extraterrestrial, for example, Martian therefore use of space technologies is required here. From this point of view, it is expedient to build space frame constructions such as: domes, lenses, spheres, Rello’s cones united by the covered transitions of ribbed type or the common covering, having good aerodynamics. In this article is emphasized the rationality of designs made of timber itself and wood materials that defines need of creation of the glued elements industry, that is possible only in presence of government support

Lateral-Torsional Buckling of Beams Elastically Restrained and Loaded with Concentrated Moments at Supports

The study presents the results of theoretical investigations into lateral-torsional buckling (LTB) of free supported bi-symetric I-beams, elastically restrained against warping at supports. Beams with loaded by moments focused at supports (with a variable the ratio of moments) and with different types of ribs were taken into account. To determine the critical moment (Mcr) of LTB of beams, the MLTB,EL program [7] and proposed in this article formula were used. The obtained results were compared with the results received from approximation formulas [6] and with FEM (LTBeam, Abaqus).

Live weight and age dynamics in Karakul lambs of Kyzylkum factory type

The article presents data on the studied dynamics of live weight of plant-type lambs of the Kyzylkumtupe from birth to 4 months of age compared to black colored lambs. The data summarized in the table show that there are certain differences in terms of live weight between colors. Moreover, higher rates, although they are statistically unreliable, are observed in black lambs at birth. Such differences in lambs of a semi circular curlicue type are 0.05 kilograms, ribbed type 0.08 kilograms, flat type 0.11 kilograms, over grown type 0.17 kilograms, and a weighted average of 0.09 kilograms. The same trend is observed at 4 months of age. Moreover, higher rates, although they are statistically unreliable, are observed in black lambs at birth. Such differences in lambs of a semi circular curlicue type are 0.05 kilograms, ribbed type 0.08 kilograms, flat type 0.11 kilograms, over grown type 0.17 kilograms, and a weighted average of 0.09 kilograms. The same trend is observed at 4 months of age. However, it should be noted that the slightly low live weight of sura lambs does not say that they are to some extent under developed. The performance of these lambs may well provide them with a sufficiently high vitality and productivity.

Determination of the Pallet Quantity Using Simulation in the FMS for Aircraft Parts

This study deals with the case study on the pallet quantity determination problem for the flexible manufacturing system producing 32 different types of aircraft wing ribs which are major structures of an aircraft wings. A Korean company has constructed the WFMS (wing rib flexible manufacturing system) that is composed of several automated equipments such as the 5-axis machining centers, the RGV (rail guided vehicles)s, the AS/RS (automated storage and retrieval system), the loading/unloading stations, and so on. Pallets play a critical role in the WFMS to maintain high system utilization and continuous work flow between 5-axis machining machines and automated material handling devices. The discrete event simulation method is used to evaluate the performance of the WFMS under various pallet mix alternatives for wing rib manufacturing processes. Four performance measures including system utilization, throughput, lead-time and work in process inventory level are investigated to determine the best pallet mix alternative. The best pallet mix identified by the simulation study is adopted in setting up and operating a real Korean aircraft parts manufacturing shop. By comparing the real WFMS’s performances with those of the simulation study, we discussed the cause of performance difference observed and the necessity of developing the CPS (cyber physical system).

Investigations into film cooling and unsteady flow characteristics in a blade trailing-edge cutback region

Unsteady flow characteristic and film cooling effect in the blade trailing edge cutback region are numerically investigated using DES (detached eddy simulation) method at three blowing ratios, four lip thickness ratios and three rib geometries. With the experimental data, reliability and accuracy of the numerical methods are validated. The results indicate that, compared with RANS (Reynolds-averaged Navier-Stokes) equations solutions, the DES method has a superior accuracy in predicting the film cooling effectiveness on trailing-edge cutback. The lip thickness has a pronounced effect on shedding vortex scale downstream the slot. As the lip thickness ratio decreases, the film cooling effect on trailing edge cutback is improved. Compared with the line ribs, the arrangement of pin fin ribs enhances the uniformity of coolant coverage on trailing edge cutback along lateral direction. However, with different types of rib, the film cooling effectiveness on the trailing edge cutback is mainly determined by the stable cooling flow structures and mixing effect between mainstream and coolant. The development of vortex system downstream the slot is significantly affected by the blowing ratio, which in turn influences the film cooling effect on trailing edge cutback.

Ultrafast water harvesting and transport in hierarchical microchannels.

Various natural materials have hierarchical microscale and nanoscale structures that allow for directional water transport. Here we report an ultrafast water transport process in the surface of a Sarracenia trichome, whose transport velocity is about three orders of magnitude faster than those measured in cactus spine and spider silk. The high velocity of water transport is attributed to the unique hierarchical microchannel organization of the trichome. Two types of ribs with different height regularly distribute around the trichome cone, where two neighbouring high ribs form a large channel that contains 1-5 low ribs that define smaller base channels. This results in two successive but distinct modes of water transport. Initially, a rapid thin film of water is formed inside the base channels (Mode I), which is followed by ultrafast water sliding on top of that thin film (Mode II). This two-step ultrafast water transport mechanism is modelled and experimentally tested in bio-inspired microchannels, which demonstrates the potential of this hierarchal design for microfluidic applications.

Evolutionary trends in the columnar cactus genus Eulychnia (Cactaceae) based on molecular phylogenetics, morphology, distribution, and habitat

Populations of the columnar cactus genus Eulychnia (Cactaceae) are an iconic sight in the Chilean Atacama Desert. The most recent taxonomic treatment of the genus suggested to accept up to seven taxa at species level based on morphological data. To date, species boundaries and infrageneric relationships in Eulychnia have not been investigated using a molecular approach. In this study, sequence data were generated for six chloroplast markers (rpl32-trnL, trnH-psbA, trnL-trnF, trnQ-rps16, trnS-trnG, and ycf1) for the seven species. Where possible, samples were collected from the south and north of the distribution range of widely distributed species, as well as plants from two morphologically distinct populations in the Atacama and Coquimbo Regions. Evolutionary trends of morphological characters were investigated using ancestral state reconstruction, and the habitat of the Chilean taxa was taken into account based on latitudinal and altitudinal distribution, precipitation regime, and vegetation zones. Two major clades were retrieved in the molecular phylogenetic hypotheses, a northern clade and a southern clade, which can easily be distinguished morphologically by differences in rib shape and type of the indumentum of the pericarpel and the hypanthium. The only Eulychnia taxon found outside Chile is most commonly accepted as Eulychnia iquiquensis subsp. ritteri. However, its isolated geographic distribution and the fact that this taxon is not most closely related to E. iquiquensis but was retrieved as sister to the rest of the northern clade in our molecular phylogenetic results support the recognition of E. ritteri at species level. Our results also provide some support for the two recently published species, E. chorosensis (previously placed in E. acida s.l.) and E. taltalensis (previously considered to be part of E. breviflora s.l.). The relationships in the southern clade need further study.

Numerical Analysis of Solar Heat Exchanger with Different Types of Ribs to Enhance Heat Transfer

Numerical Analysis of Solar Heat Exchanger with Different Types of Ribs to Enhance Heat Transfer

Numerical investigation and performance analyses of rectangular mini channel with different types of ribs and their arrangements

An investigation of a three-dimensional rectangular minichannel with different types of longitudinal vortex generators, (rectangular and trapezoidal) which are considered as ribs along the channel, is carried out. Five different models with different angles of attack and height of ribs have been designed and studied numerically for analyzing the heat transfer and overall performance of the channel in single-phase laminar flow. The results indicate that the configurations with the attack angles of 60° have the best heat transfer performance. An augmentation for heat transfer performance improves with the increase of rib's height and the Reynolds number in the channel, however, flow resistance increases in return. Minichannels with both rectangular and trapezoidal ribs have better results for heat transfer and flow performance in comparison to a minichannel with rectangular ribs only. The model with all trapezoidal ribs leads to best overall performance due to its better flow performance, which is a crucial factor in the overall efficiency. The overall performance of the minichannel enhanced by 52.7% for the case “M3” in comparison with the smooth channel.

Photosensitive adhesive bonding process of magnetooptic waveguides with Si guiding layer for optical nonreciprocal devices

A photosensitive adhesive bonding process for a magnetooptic waveguide for an optical isolator employing a nonreciprocal guided-radiation mode conversion is investigated at 1.55 µm. The magnetooptic waveguide is a straight rib type, and it is fabricated by bonding the Si guiding layer to a magnetic garnet. In the fabrication process, an adhesive material is diluted to obtain a certain thickness before depositing on a silicon-on-insulator (SOI) substrate. The relationship between the percent dilution ratio and the thickness of the adhesive layer is considered. The smallest gap thickness is found to be 0.66 µm at a dilution ratio of 2%.