Row Of Rods Research Articles

An experimental investigation of the thermal performance of solar collectors utilizing finned aluminum can pipes

An innovative experimental study is presented to improve the performance of solar collectors designed for solar drying systems, focusing on the use of recycled aluminum can waste and the development of the air solar collector. The latter’s absorber is made up of 10 cans with a diameter of 65 mm, a length of 160 mm and a thickness of 0.3 mm, forming a cylindrical finned pipe. Several collector configurations under identical weather conditions, including four collectors with different rows of rods (4, 8, 12–14 rows) and a single collector, were analyzed and compared. The thermal performance of this new collector model was assessed on the basis of solar fluxes and collector inlet and outlet temperatures, collected during the month of September 2021. Experimental results revealed that this collector can increase the outlet temperature of air from 32°C up to 130°C, in the case of a 14-row collector. The study also showed that, at low flow rates, the can-equipped collector achieves an efficiency of 54% for the case of a 14-row collector, compared with 34% for the simple case, representing a 20% improvement over the single case. The study also showed that, at low flow rates, the can-equipped collector achieves higher outlet temperatures.

Instability mechanism and failure criteria of large-span flexible PV support arrays under severe wind

Compared with independent flexible PV support, the entire structure force performance and transfer mechanism of inter-row cables and inter-span rods of flexible PV support arrays are more complex, it is easy to have large vibration or even instability failure under strong wind. In this study, the three-span and five-row flexible PV support array of a 66 MW Fishery-PV Complementary demonstration site in the eastern coastal region of China is used as the research object. The rigid body pressure measurement wind tunnel test was designed and carried out, and the wind pressure distribution characteristics of the PV panels surface were analyzed. A three-dimensional explicit dynamics model of the flexible PV support array considering inter-row cables and inter-span rods is established, and the wind-induced dynamic response characteristics and instability processes of the large-span flexible PV support array are effectively simulated. Finally, the instability mechanism of the large-span flexible PV support array is revealed, and the dual failure criteria based on structural deformation and energy increment are proposed. Results demonstrated that the maximum values of displacement and von Mises stress of the large-span flexible PV support array are concentrated in the 1st row of the span in the windward side. The array under 0° and 180° wind direction angles induces local instability and failure at wind speeds of 51 m/s and 46 m/s due to the failure of the 1st row of triangular rods and crossed diagonal rods on the windward side, respectively, and the rods instability mechanisms are Eulerian buckling mechanism and Limit point buckling mechanism, respectively. When the axial compression ratio [Δ] > 0.1 or the strain energy increment [ΔU] > 1.0 × 105J of the instability rod, the structure will be locally destabilized. This paper presents a systematic work around the wind-induced response and instability characteristics of the large-span flexible PV support array, the results are of significance for the engineering application of solar energy generation structures.

Tunable topological slow-light in gyromagnetic photonic crystal waveguides with unified magnetic field.

We have proposed a tunable topological slow-light in a photonic crystal (PC) waveguide with unified magnetic field. The waveguide is constructed by bringing close two gyromagnetic photonic crystals (GPCs) with different structural parameters and introducing a row of Al2O3 rods as the coupling layer. The two GPCs are applied with a unified external static magnetic field (ESMF) instead of two opposite ESMFs. Such waveguide supports a slow-light state originated from the coupling effect of two one-way edge states on both sides of the waveguide. By simply changing the strength of ESMF, one can achieve a tunable slow-light state with large normalized delay-bandwidth product (NDBP) (0.36< NDBP <0.84). Based on these excellent properties, we further design an optical delayer with a compact structure and expansibility simultaneously. This unique topological slow-light state with simple unified magnetic condition, high maneuverability and strong immunity to defects holds promise for many fields such as signal processing, optical modulation, and the design of various slow-light devices.

Characterization of Nepalese Bread Wheat Landraces Based on Morpho-Phenological and Agronomic Traits

Due to the presence of valuable genes that contribute to a variety of functional traits, landraces kept in Genebank can be extremely important in wheat breeding. A study was conducted based on agro-morphological traits of Nepalese bread wheat landraces to explore genetic diversity among them. Using a replicated rod row design, 200 landraces were evaluated during the winter season of 2018 and 2019 at Khumaltar, Lalitpur, Nepal. The degree of variations among landraces was determined using univariate and multivariate statistical tools. The Shannon-Weaver diversity index (H’) showed a wide range of variations among the studied landraces, ranging from 0.55 to 0.91 in quantitative traits and 0.63 to 0.85 in qualitative traits.Principal component (PC) analysis with an eigenvalue greater than 1 reveals that 68% of the variability for quantitative traits is contributed by the first five principal components whereas 67% of the variability of qualitative traits is governed by the first four principal components. UPGMA (Unweighted pair-groups methods through arithmetic average) clustered 202 landraces into five groups according to quantitative charterers.Identified advantageous adaptive traits through the analysis of variability within the accessions, will be used by breeders for crosses in the breeding or used directly by farmers.

Digital Regeneration and Database Construction of Hunan Embroidery Needlework under the Perspective of Artificial Intelligence

Abstract In order to explore the development path of Hunan embroidery under the vision of artificial intelligence, promote the digital regeneration and database construction of Hunan embroidery stitches, the communication, and interaction between Hunan embroidery brands and the public, and create more possibilities for revitalizing the culture and industrial development of non-heritage Hunan embroidery. In this paper, a mechanics model of Hunan embroidery stitch is established based on the finite element idea under the view of artificial intelligence. The single yarn in the yarn is regarded as a frictionless articulation of some rows of elastic rods with a circular cross-section. The elastic rod can only be subjected to axial force without a moment, and it is a uniform, continuous, and completely elastic isotropic body. Using the displacement method, the displacement of the unit node is taken as the basic unknown quantity, the displacement in the unit is assumed to be linearly distributed, and the displacement of any node in the unit is obtained by linear interpolation. The strain, stress, and stiffness matrices of the elastic rod unit are derived, the equilibrium equations are given, and a database is established. The results of the study showed that consumers of all age levels thought that the patterns representing Hunan embroidery mainly include Hunan characteristic landscapes, portraits of Hunan great men, traditional flowers, birds and animals, and totems of Chu culture, etc., among which Hunan characteristic landscape accounted for 54% of the largest proportion. It provides a development direction for the inheritance and protection of Hunan embroidery skills.

Rainbow trapping and releasing based on the topological photonic crystals and a gradient 1D array

Topological photonic crystal provides a platform for robust energy transport in photonic systems. In this letter, we propose a method for realizing rainbow trapping and releasing based on the topologically protected defect modes in dielectric photonic crystals. The photonic states of different frequencies are separated and trapped at different positions to form the topological rainbow. The all-dielectric planar nanostructures consist of deformed honeycomb lattices and a gradient 1D array, which is distinct from previous platforms where edge states appear at the interface between trivial and nontrivial crystals. Due to the simplification of the configuration, we can selectively control the stop position of the wave by modifying the bottom row of dielectric rods so that light can switch between the trapping state and releasing state. The robustness of the slowing light system is also investigated. These results are beneficial to multiple frequency tuning. The simplified structure could offer a novel method for micro-miniaturizing and applying optical communication equipment, such as optical storage and optical buffer.

Thermal analysis of baffle jetting in fuel rod assembly

Baffle jetting plays a significant role when it comes to safe operation of nuclear power plants. The baffle jetting phenomenon is the generation of horizontal flow impingement on fuel/control rods during the outward flow of the primary coolant into a nuclear reactor. To understand the flow and heat transfer characteristics under the baffle jetting conditions, large eddy simulations (LES) of flow around a 6×6 fuel rod assembly were conducted. Three Reynolds numbers based on jet width and inlet velocity were considered 5010, 10 000, and 20 000. A temperature difference of 5°C between the inlet fluid and the heated rods was considered to analyze the heat transfer characteristics within the assembly under baffle jetting. Various flow parameters were computed such as pressure coefficients along different rods, mean and fluctuating forces, Strouhal number, local and averaged Nusselt numbers. LES results were validated against experimental measurements and other numerical data. It was observed that the effect of the baffle jet was more significant on the first stream-wise row of rods with the stagnation points at the lower part of these rods. Furthermore, the averaged Nusselt number was found to be higher on rods in the stream-wise direction of the jet, rather than at other locations.

Towards Perfect Ultra-Broadband Absorbers, Ultra-Narrow Waveguides, and Ultra-Small Cavities at Optical Frequencies.

In this study, we design ultra-broadband optical absorbers, ultra-narrow optical waveguides, and ultra-small optical cavities comprising two-dimensional metallic photonic crystals that tolerate fabrication imperfections such as position and radius disorderings. The absorbers containing gold rods show an absorption amplitude of more than 90% under 54% position disordering at nm. The absorbers containing silver rods show an absorptance of more than 90% under 54% position disordering at nm. B-type straight waveguides that contain four rows of silver rods exposed to air reveal normalized transmittances of 75% and 76% under 32% position and 60% radius disorderings, respectively. B-type L-shaped waveguides containing four rows of silver rods show 76% and 90% normalized transmittances under 32% position and 40% radius disorderings, respectively. B-type cavities containing two rings of silver rods reveal 70% and 80% normalized quality factors under 32% position and 60% radius disorderings, respectively.

Super strong wide TM Mie bandgaps tolerating disorders

This study demonstrates the appearance of super intense and wide Mie bandgaps in metamaterials composed of tellurium, germanium, and silicon rods in air that tolerate some disordering of rod position and rod radius under transverse magnetic (TM) polarized light waves. Tellurium metamaterials reveal {mathrm{TM}}_{01}, {mathrm{TM}}_{11}, {mathrm{TM}}_{21}, {mathrm{TM}}_{02}, {mathrm{TM}}_{12} Mie bandgap modes in which {mathrm{TM}}_{01}, {mathrm{TM}}_{11}, and {mathrm{TM}}_{21} tolerate high rod-position disordering of 50% and rod-radius disordering of 34 and 27%, respectively. Results for germanium metamaterials show Mie bandgap modes {mathrm{TM}}_{01}, {mathrm{TM}}_{11}, and {mathrm{TM}}_{21}, in which {mathrm{TM}}_{01} and {mathrm{TM}}_{11} tolerate rod-position disordering of 50%, and rod-radius disordering of 34 and 20%, respectively. Using these characteristics of {mathrm{TM}}_{11} in germanium metamaterials under position and radius disordering, ultra-narrow straight, L-shaped, and crossing waveguides that contain 14, four, and two rows of germanium rods in air are designed. Also, it is shown that {mathrm{TE}}_{01} Mie bandgap appears in metamaterials containing a high refractive index, and disappears in metamaterials with a lower refractive index such as silicon; in contrast, a new phenomenon of intense and broadband {mathrm{TM}}_{01}, {mathrm{TM}}_{11}, and {mathrm{TM}}_{21} in metamaterials with a lower refractive index such as silicon appear. In silicon-based metamaterials, {mathrm{TM}}_{01} tolerates high rod-position and rod-radius disordering of 40% and 34%, respectively, and {mathrm{TM}}_{11} shows robustness to rod-position and rod-radius disordering of 20%. This strong tolerance of disordering of TM modes in tellurium, germanium, and silicon metamaterials opens a new way to design small, high-efficient, and feasible fabrication optical devices for optical integrated circuits.

Chalcogenide Photonic Crystal: Channel Drop Filter

In the present paper, we have studied a two-dimensional photonic crystal structure of square lattice as channel drop filter application. Photonic crystal structure of square lattice was constructed with circular rods are embedded in air medium. The channel drop filter was designed with a point defect cavity nearby a waveguide, which constructed by removing a single row of rods near cavity. The cavity was designed by removing a number of rods, which characterized with dimension of the cavity. The transmission spectra were analyzed for the channel drop filter with the dimension of the cavity.

Bipolar electrodeposition of spongy lead from alkaline solutions on a flow wire cathode

For alkali solution electrolysis resulting in the production of lead dioxide on anode and lead sponge on cathode, the concentration of lead on cathode should be high and that on anode should be low. To prevent sponge from coming off of the cathode leading to electrode bridging, low current densities should be used. In this case, the adhesion of sponge to cathode will be stronger. Another solution would be to use a dielectric mesh to separate the cathode and the anode. To improve the process conditions, it is proposed to use a porous lead sponge to separate catholyte from anolyte. The sponge can act as a flow cathode at the same time. A metallic mesh, a row of parallel rods or plates or other type of permeable cathode are proposed as the basis for growing the sponge. The proposed technique helps precipitate the lead sponge predominantly on the backside of the cathode preventing the cathode deposit from hitting the anode and thus preventing electrode bridging. As the cathode sponge goes all the way across the section of the cell, the pregnant solution concentrates in between the cathodes while the weak solution concentrates near the anodes. This leads to a higher depletion of the solution and helps lower the concentration of lead near the anodes and control the generation of lead oxides on anode. Compared with conventional techniques when the sideways growth of the spongy precipitate is constrained by the cross section of the cell (from 200&ndash;300 to 400&ndash;500 A/m2), this technique also helps significantly increase the current density at low power consumption and obtain a high-purity lead sponge. In comparison with high-intensity electrolysis techniques, the above described technique helps significantly decrease the power consumption, improve the purity of cathode deposits and lower the concentration of lead in the spent electrolyte. This process does not require higher temperatures, thus there is no need in alkaline vapour suppression equipment.

Ultra-narrow, highly efficient power splitters and waveguides that exploit the TE01 Mie-resonant bandgap.

In this paper, ultra-narrow and highly-efficient straight and Ω-shaped waveguides, and Y-shaped and T-shaped optical power splitters composed of two rows of two-dimensional germanium rods in air are designed and simulated. The position-disordering effect on the waveguides is considered. Finite-difference time-domain numerical simulation results for two rows of straight and Ω-shaped waveguides with no position disordering at the normalized frequency of a λ=0.327 show optical transmission of 90%, and two rows of Y-shaped and T-shaped power splitters with no position disordering have transmissions >46% for each output branch at the normalized frequency of a λ=0.327. Also, the straight and Ω-shaped waveguides with four rows of germanium rods tolerated position disordering of η = 10%. The proposed ultra-narrow waveguides and power splitters are vital components in high-density and all-dielectric optical integrated circuits.

Characterization and Diversity Assessment of Nepalese Garlic (Allium sativum L.) Landraces

A research was carried out at the field of National Agriculture Genetic Resources Centre (NAGRC), Khumaltar, Lalitpur, Nepal in 2019 with the objective of phenotypic characterization and genetic diversity assessment of thirty-seven local garlic landraces. The phenotypic diversity was assessed based on fifteen qualitative and nine quantitative characters by sing non replicated rod row design following the descriptors developed by IPGRI, 2001. Descriptive statistics were calculated by using MS Excel 2016 and UPGMA clustering and PCA was done with MINITAB-17. The diversity index (H’) and coefficient of variation for different traits ranged from 0.54-0.96 and 16.89-87.85, respectively. Four clusters identified and CO 10307, CO 10482 and CO 10615 of fourth clusters were superior in terms of quantitative characters. Five principal components contributed95.2% of the cumulative variance. This result will be helpful for breeder and researchers to comprehensively understand the agro-morphological characters as well as diversity of the Nepalese garlic collection.

An Experimental Study of the Leakage Flow Effect on the Film Cooling Effectiveness of a Gas Turbine Shroud

Abstract In the vicinity of gas turbine blades, a complex flow field is formed due to the flow separation, reattachment, and secondary flows, and this results in a locally non-uniform and high heat transfer on the surfaces. The present study experimentally investigates the effects of leakage flow through the slot between the gas turbine vane and blade rows on the film cooling effectiveness of the forward region of the shroud ring segment. The experiment is carried out in a linear cascade with five blades. Instead of the vane, a row of rods at the location of the vane trailing edge is installed to consider the wake effect. The leakage flow is introduced through the slot between the vane and blade rows, and additional coolant air is injected from the cooling holes installed at the vane’s outer zone. The effects of the slot geometry, cooling hole configuration, and blowing ratio on the film cooling effectiveness are experimentally investigated using the pressure-sensitive paint (PSP) technique. CO2 gas and a mixture of SF6 and N2 (25% + 75%) are used to simulate the leakage flow to the mainstream density ratios of 1.5 and 2.0, respectively. The results indicate that the area-averaged film cooling effectiveness is affected more by the slot width than by the cooling hole configuration at the same injection conditions, and the lower density ratio cases show higher film cooling effectiveness than the higher density ratio case at the same cooling configuration.

Hydrodynamics of coolant in VVER reactor core with fuel assemblies of various designs

The article presents the results from experimental investigations into local coolant flow fluid dynamics that were carried out on the fragmental model of a VVER-type pressurized water reactor’s mixed core consisting of two types of fuel assemblies (FAs): TVSA-T (one segment) and TVSA-T.mod.2 (two segments). The coolant flow processes in the fuel rod bundle were simulated on an aerodynamic test bench. The pressure field in the flow was measured using a five-channel pneumometric probe. The obtained pressure field in the flow was recalculated for the coolant velocity vector according to the dependences derived during calibration. For drawing up a detailed flow motion pattern, a characteristic model cross section area was separated, which included the space between the assemblies and four fuel rod rows in each TVSA-type fuel assembly. The spatial distribution of coolant flow velocity projections was analyzed, as a result of which it became possible to reveal the regularities associated with the streamlining of spacer, mixing-, and combined-spacer grids in TVSA assemblies by coolant; to determine coolant cross flows resulting from streamlining of hydraulically nonidentical grids and to determine their localization in the experimental model longitudinal and cross sections; and to reveal the effect of accumulating flow hydrodynamic disturbances in the model longitudinal and cross sections resulting from the staggered arrangement of hydraulically nonidentical grids. The results obtained from investigations of interassembly interaction of coolant between the neighboring TVSA-T and TVSA-T.mod.2 assemblies have been adopted for practical use at JSC “Afrikantov OKBM” in estimating the thermal reliability of VVER-type reactor cores and have been included in the database for verification of computation fluid dynamics computer programs (CFD codes) and detailed cell-wise numerical analysis of VVER reactors’ core.

Screening of rice genotypes for leaf blast resistance under field condition

Blast, caused by Pyriculariagrisea (Sacc.) is the most destructive disease of rice in Nepal. To identify the sources of leaf blast resistance in rice genotypes, a field experiment was conducted under natural epiphytotic condition at National Plant Pathology Research Centre (NPPRC), Khumaltar, Lalitpur, Nepal during summer season in 2018 and 2019.A total of 128 rice genotypes in 2018 and 291during 2019 including resistant check (Sabitri) and susceptible check (Shankharika/Mansuli) were tested. Field experiment was conducted in single rod row design. Leaf blast disease assessment was done according to 0-9 scale. During 2018, 59 entries were highly resistant (Score 0), 34 resistant (Score 1), 26 moderately resistant (Score 2-3), 5 were moderately susceptible (Score 4-5), 4 susceptible (Score 6-7) and none of them were highly susceptible (Score 8-9) to leaf blast. Similarly, in 2019, 6 lines were highly resistant, 70 resistant, 196 moderately resistant, 15 lines were moderately susceptible, 4 susceptible and none of them were highly susceptible to the disease. Only, one genotype NR2179-82-2-4-1-1-1-1 (Score 1) was found resistant in both years. Similarly, genotype NR2182-22-1-3-1-1-1 (Score 2-3) was found moderately resistant. Some of the genotypes were found resistant in 2018 which become moderately resistant in 2019, they were NR2180-20-2-5-1-1-1-1, IR97135-8-3-1-3, IR98786-13-1-2-1, NR2181-139-1-3-1-1-1-1, and IR13F402. So, findings of these resistant and moderately resistant genotypes could be used in resistant source for the development of leaf blast resistant rice varieties through hybridization in future.

A Zebrafish Model of Retinitis Pigmentosa Shows Continuous Degeneration and Regeneration of Rod Photoreceptors.

More than 1.5 million people suffer from Retinitis Pigmentosa, with many experiencing partial to complete vision loss. Regenerative therapies offer some hope, but their development is challenged by the limited regenerative capacity of mammalian model systems. As a step toward investigating regenerative therapies, we developed a zebrafish model of Retinitis Pigmentosa that displays ongoing regeneration. We used Tol2 transgenesis to express mouse rhodopsin carrying the P23H mutation and an epitope tag in zebrafish rod photoreceptors. Adult and juvenile fish were examined by immunofluorescence, TUNEL and BrdU incorporation assays. P23H transgenic fish expressed the transgene in rods from 3 days post fertilization onward. Rods expressing the mutant rhodopsin formed very small or no outer segments and the mutant protein was delocalized over the entire cell. Adult fish displayed thinning of the outer nuclear layer (ONL) and loss of rod outer segments, but retained a single, sparse row of rods. Adult fish displayed ongoing apoptotic cell death in the ONL and an abundance of proliferating cells, predominantly in the ONL. There was a modest remodeling of bipolar and Müller glial cells. This transgenic fish will provide a useful model system to study rod photoreceptor regeneration and integration.

Combined Numerical and Experimental Investigations into the Local Fluid Dynamics of Coolant Flow in the Mixed Core of a VVER Reactor

The article presents the results from experimental investigations into local coolant flow fluid dynamics that were carried out on the fragmental model of a VVER-type pressurized water reactor’s mixed core consisting of two types of fuel assemblies (FAs): TVSA-T (one segment) and TVSA-T.mod.2 (two segments). The coolant flow processes in the fuel rod bundle were simulated on an aerodynamic test bench. The pressure field in the flow was measured using a five-channel pneumometric probe. The obtained pressure field in the flow was recalculated for the coolant velocity vector according to the dependences derived during calibration. For drawing up a detailed flow motion pattern, a characteristic model cross section area was separated, which included the space between the assemblies and four fuel rod rows in each TVSA-type fuel assembly. The spatial distribution of coolant flow velocity projections was analyzed, as a result of which it became possible to reveal the regularities associated with the streamlining of spacer-, mixing-, and combined-spacer grids in TVSA assemblies by coolant; to determine coolant cross flows resulting from streamlining of hydraulically nonidentical grids and determine their localization in the experimental model longitudinal and cross sections; and to reveal the effect of accumulating flow hydrodynamic disturbances in the model longitudinal and cross sections resulting from the staggered arrangement of hydraulically nonidentical grids. The results obtained from investigations of inter-assembly interaction of coolant between the neighboring TVSA-T and TVSA-T.mod.2 assemblies have been adopted for practical use at AO Afrikantov OKBM in estimating the thermal reliability of VVER-type reactor cores and have been included in the database for verification of computation fluid dynamics computer programs (CFD codes) and detailed cell-wise numerical analysis of the core of VVER reactors.

Surface wave photonic quasicrystal

In developing strategies for manipulating surface electromagnetic waves, it has been recently recognized that a complete forbidden bandgap can exist in a periodic surface-wave photonic crystal, which has subsequently produced various surface-wave photonic devices. However, it is not obvious whether such a concept can be extended to a quasi-periodic surface-wave system that lacks translational symmetry. Here, we experimentally demonstrate that a surface-wave photonic quasicrystal that lacks short-range order can also exhibit a forbidden bandgap for surface electromagnetic waves. The lower cutoff of this forbidden bandgap is mainly determined by the maximum separation between the nearest neighboring pillars. Point defects within this bandgap show distinct properties compared to a periodic photonic crystal in the absence of translational symmetry. A line-defect waveguide, which is crafted out of this surface-wave photonic quasicrystal by shortening a random row of metallic rods, is also demonstrated to guide and bend surface waves around sharp corners along an irregular waveguiding path.

Analysis of flow at the vicinity of vegetation stems in the floodplain of a compound open channel

ABSTRACT An analysis of flow was carried out in this study to find the effects of trees on the flow structure in a straight compound open channel. To resemble the vegetation stem, two rows of vertical rods were installed on the floodplain of an asymmetrical compound channel. Two-dimensional flow velocity was measured using Particle Image Velocimetry. The results showed a decreasing trend in turbulent kinetic energy and turbulent intensity along the floodplain. At low flow depth, a significant decrease was observed in mean velocity and kinetic energy. Similar reduction was observed at the intersection of floodplain and main channel and around the stems. Under this condition, the direction of velocity vectors changed from floodplain to the main channel. However, this trend was reversed at higher flow depths. This reversal was due to the changes in momentum transfer and shear stress at the intersection of floodplain and main channel. Additionally, a numerical analysis showed that vortices are formed at the junction of the floodplain and main channel.