Single Row Research Articles

Evaluating Structural Performance of U-shaped Precast Concrete Modular Joints

We conducted a joint tensile test and a wall cyclic loading test to assess the structural performance of the U-shaped precast concrete (PC) modular joint. The rebar experienced fracture at the edge of the L-shaped steel during the joint tensile test. The calculated average ratio of the maximum load to the nominal strength, based on the strength of the rebar, was 1.07. The result of the wall cyclic loading test showed that the PW-1R specimen, featuring a single row of PC joints, exhibited ratios of the maximum moment to a nominal bending moment of 1.19 and 1.00 in the positive (+) and negative (-) directions, respectively. Meanwhile, the ratios of the maximum moment to the nominal bending moment for the PW-2R specimen with two rows of PC joints were 1.20 and 1.06 in the positive (+) and negative (-) directions, respectively. The adequate edge distance for the joint hardware must be ensured to increase the strength of the PC joint wall.

Kahakuloa operculispora, a new Hawaiian simple thalloid liverwort in a new genus and family, Kahakuloaceae (Fossombroniales)

Kahakuloa operculispora, a new simple thalloid liverwort endemic to Hawaiʻi, so far only known from high elevation bogs in western Maui, is described and illustrated. The thallus has prominent reddish-purple rhizoids, uniseriate ventral slime papillae and lacks scales. The plants are dioicous; male plants have antheridia sunken in several rows of dorsal chambers, subtended by scales, while female plants have clustered archegonia enclosed by thick, barrel-shaped involucres that develop serially at the plant apex, before fertilization, and are arranged in a single dorsal row at maturity; perichaetial scales and pseudoperianths (defined as involucres developing after fertilization) are lacking. The capsules are spherical, 2−3 stratose, and dehisce irregularly; the spores are areolate and have a unique operculum-like disk on the proximal face. Molecular and morphological evidence supports placement of the plant in a new genus and family in the order Fossombroniales, suborder Fossombroniineae. Kahakuloa is the first liverwort genus endemic to Hawaiʻi, and Kahakuloaceae is the only known endemic Hawaiian land plant family.

NITROGEN USE EFFICIENCY IN SUNFLOWER (HELIANTHUS ANNUUS L.) INFLUENCED BY VARIOUS FERTIGATION AND BED PLANTING TECHNIQUES

Low nitrogen fertilizer use efficiency and high losses of nitrogen are the critical challenges being faced by sunflower grower. To address these concerns, an experiment was carried out during spring 2021 at the Agronomic research area of the Agriculture University, Faisalabad. The randomized complete block design experiment was used with three replications under split plot arrangement. The 5m x 3m net plot size was kept with sowing procedures retained in the main plot and nitrogen application techniques kept in the sub plot. The experiment was planted on 20-02-2021. The matured crop was reaped on 18 June, 2021 manually. The single row hand drill was used to sow sunflower crop. The 75 cm line to line and 25 cm plant to plant distance was maintained. The results indicated that plant population ranged from 73 to 74 with maximum plant height of 174.33 cm, stem diameter (3.70 cm), head diameter (23.13 cm), number of achenes per head (1237.6), 1000-achene weight (68.17 g), highest biological yield (10.92 t ha-1), achene yield (3.22 t ha-1), harvest index (29.48 %) and protein contents (29.03 %) was observed in treatment where nitrogen was applied by fertigation method and sunflower was sown on beds. But maximum oil contents (41.78 %) were observed where nitrogen was side dressed and flat sowing technique was adopted for crop sowing. It is found that use of fertigation method of nitrogen application and bed planting techniques proved to be the best combination for improving growth, yield & yield relating attributes and improve fertilizer use efficiency with lower nitrogen losses for sunflower (Hybrid-33) under agro-climatic conditions of Faisalabad.

Flame propagation modes for iron particle clusters in air — Part I: Transition from continuous to discrete propagation mode under weak convection effects

Iron powder can serve as an energy carrier and help generate heat and power in a clean and sustainable manner. In this paper, we analyze one of the challenges related to iron combustion: the mode of flame propagation. Depending on the conditions, an iron dust flame can propagate in either the continuous mode, with neighboring particles burning simultaneously, or in a discrete mode, with each particle burning separately, i.e. as a percolating wave. We use particle-resolved simulations including the heterogeneous reaction of iron with oxygen and detailed transport models. Simulations are carried out with multiple particles in a single row with hot gas at the inlet for initiating combustion under weak convection effects. Continuous and discrete flame propagation modes are identified and the particle distance, at which the transition from the continuous to the discrete propagation mode occurs, is calculated for different particle diameters. It is found that the transition from one mode to another occurs close to stoichiometry and the maximum flame reaction front speed is within the range of experiments with similarly sized particles. The flame propagation mode transitions to the discrete mode for larger particles at slightly lower particle distances than smaller particles due to higher thermal inertia. The discreteness parameter is modified to take into account the effect of heating from burnt particles on the unburnt ones. This results in an overall adequate prediction of the numerically found transitional distances under weak convection effects.Novelty and significance: As a carbon-free energy carrier, there is a great requirement for exploring the fundamental and application aspects of iron combustion. One critical issue for the heterogeneous combustion of iron is the mode of flame propagation. While previous studies have relied on simplified models and simplifying assumptions, in this work, we carry out detailed boundary layer resolved simulations of multiple particles with varying distances between the particles. Beyond a critical particle spacing, the mode of flame propagation transitions from the continuous mode where multiple particles burn simultaneously, to the discrete mode where the particles burn standalone. The scaling of such a transition is improved with the help of appropriate temperature based properties and the length scale. Our work is significant in understanding the fundamentals of flame propagation in iron clusters and can help in the development of Euler–Lagrangian models where tens of thousands of particles need to be simulated.

Assessment of the Existing Feeding and Housing Management Practices of Dairy Animals in Rajbanshi Dairy Farmers

Feeding and housing play a very significant role in utilizing the real potential of dairy animals as both are prerequisite factors for milk production. The study was conducted in the Coochbehar district of West Bengal to explore the existing feeding and housing management practices followed by Rajbanshi dairy farmers. A total sample size of 200 dairy farm families was taken using multistage random sampling for the present study. It was observed that the majority of dairy farmers (63.00%) followed the system of stall feeding and for feeding green fodder majority (94.50%) of dairy farmers depended on naturally grown vegetation/ pastures. The study revealed that the majority (68.00%) of dairy farmers fed paddy straw as dry fodder followed by 32.00 percent of dairy farmers who fed both paddy straw and wheat straw to their animals. The majority (83.00%) of the dairy farmers did not feed mineral mixtures to their animals. Among animal sheds a vast majority (83.50%) were kaccha and the maximum percentage (87.50%) of the housing systems were single row. The majority (83.00%) of the sheds had a full wall in addition to this the walls were made up of tin sheets (45.00%) as well as jute sticks (37.00%). Rice straw was used as bedding material in the winter season by 62.00% percent of dairy farmers. The existing feeding and housing practices among Rajbanshi dairy farmers need improvement, including increased awareness of fodder cultivation, promotion of home-prepared feed, mineral supplementation, better shed construction, sanitation, and waste management.

Mallomonas rimosa sp. nov. (Synurales, Chrysophyceae)—a rare tropical species from Vietnam

A new species, Mallomonas rimosa sp. nov., is described from Vietnam based on silica-scale morphology observed using scanning and transmission electron microscopy. Mallomonas rimosa belongs to section Torquatae and is most similar to M. eoa, M. prora, M. serrata, M. scrobiculata, M. pumilio var. dispersa, M. caverna, and M. lanalhuensis. The main distinctive features of scales of the newly described species are the shield ornamentation with small, circular, and evenly spaced pits and the single row of papillae on each side of the anterior flange. Mallomonas rimosa was found in water bodies with acidic conditions, low mineralization, and high temperature.

Optimization of Three-Dimensional Blade and Variable Stators for Efficiency and Stability Enhancement of Multistage Axial Flow Compressor at Variable Speeds

Abstract High efficiency and wide stability at variable speeds are equally important to the design and operation of multistage axial flow compressors. However, published research works on three-dimensional design optimization of compressors are so far mainly limited to a single blade row or stage at design speed due to the curse of dimensionality. Moreover, optimization of variable inlet guide vanes (IGV)/stators for off-design operations is carried out by using a rapid but low-fidelity prediction tool and is generally independent of design optimization of blade geometry. To tackle these issues, a three-dimensional holistic design and adjustment optimization method is developed in which both three-dimensional blade geometry and variable IGV/stators are optimized simultaneously for better efficiency and stability at design and off-design conditions. Metamodel-interpreted data mining method and adaptive infilling strategy are used respectively to enhance the capability of the metamodeling and optimization. The developed method is then applied to a modern highly loaded 3.5-stage transonic axial flow compressor at both design and part-design speeds. The results show that the stall margin is extended from 8.23% to 19.65% at 70% design speed while peak efficiency is slightly improved at design speed. The flow mechanisms responsible for the efficiency enhancement at design speed are mainly associated with the reduced total pressure loss in stators as well as inter- and intra-stage loading redistribution. The stability enhancement at 70% design speed is mainly achieved by loading the front blade rows while unloading the limiting rear blade row through variable IGV/stators adjustment. The developed holistic design and adjustment optimization method with the aid of metamodel-interpreted data mining is of great application value for the design and adjustment of advanced multistage axial flow compressors.

Endoscopic Hip Abductor Tendon Repair Results in Successful Outcomes With 5- to 10-Year Follow-up

PurposeThe purpose of this study is to report the outcomes of endoscopic repair in a consecutive series of patients with follow-up ranging from five to ten years. MethodsSixty-five consecutive hips in 63 patients (2 bilateral) undergoing endoscopic abductor tendon repair with minimum five-year follow-up were assessed with modified Harris Hip Scores (mHHS). The minimal clinically important difference (MCID) was determined as one half the standard deviation of the amount of improvement. ResultsMean age was 56.6 years (SD 11.3) with 58 females and 5 males. Follow-up was obtained on 64 hips (98.5%) at mean 85 months (SD 15.7). There were 33 full-thickness and 32 partial-thickness tears; 40 gluteus medius tears, 23 medius and minimus tears, and 2 isolated minimus tears. 50 patients (52 hips) underwent concomitant arthroscopy of the hip joint, including 15 with correction of Femoroacetabular Impingement (FAI)). The mean preop mHHS was 48.4 (SD 15.7) and postop 83.4 (SD 15.9); reflecting of 34.9 (95% confidence interval 34.9 ± 4.3) with 92.2% achieving the MCID of 8.7. There were no complications. Three patients underwent further surgery: One underwent total hip replacement at 11 months following abductor repair; one underwent repeat arthroscopy for joint debridement at 12 months following repair; and one underwent revision abductor repair at 6 years postop. ConclusionsCollectively, with 5-10 year follow-up, patients undergoing endoscopic abductor tendon repair can respond exceptionally well, with 92.2% achieving MCID; even among a heterogeneous group of single and two tendon involvement with partial and full thickness tears, undergoing single and double row repair. Level of EvidenceLevel IV, Case Series

Experimental and numerical investigation on the film-cooling a gas turbine vane pressure side with various internal rib angles

To study the effects of the internal rib angles on the film cooling performance of turbine vane, a single row of film cooling holes on the pressure side was investigated using pressure sensitive paint (PSP) technology and numerical approaches. For the four internal ribbed cooling channels (smooth channel, 30°, 60° and 90° ribs), the distributions of film cooling effectiveness at three blowing ratios (0.3, 0.5, 0.8) and two density ratios (1.0, 1.5) were studied. Experimental results showed that the 30° rib is the most effective for most working conditions, followed by the smooth channel. When the blowing ratio (M) increases from 0.3 to 0.8, the film cooling effectiveness improvement of the 30° rib increases from 32.2% to 96.4% compared with the smooth channel. With the exception of slight variations at the local level, the area-average film cooling effectiveness for various angled ribs decreases as the blowing ratio increases within the scope of the experiment. The adherence of the cooling jet improves as the density ratio increases. For different angled ribs, the spanwise coverage of the film expands, the area with high cooling effectiveness expands, and the spanwise average film cooling effectiveness increases at the downstream regions of the film holes. With the increase of blowing ratio, the increment of density ratio on film cooling effectiveness is increased. The increment ratio for the smooth channel is the largest as the density ratio increased from 1.0 to 1.5 and it reaches 135 % when blowing ratio is 0.8. The film cooling effectiveness of film discharge for a turbine vane is systematically investigated with different rib configurations. The current study is useful for designing the pressure side of turbine vanes.

Baetidae (Insecta: Ephemeroptera) of Aurès Mountains (Algeria): A New Species of the Baetis alpinus Species Group, with Notes on Baetis Laech, 1815 Biogeography within Maghreb.

A new species, Baetis (Baetis) dihyaesp. nov., belonging to the Baetis alpinus species group, is described and illustrated based on larval material collected in the Aurès Mountains (northeastern Algeria) in 2020-2021. This new species is closely related to three European species, e.g., Baetis (B.) alpinus (Pictet, 1843); B. (B.) nubecularis Eaton, 1898; and B. (B.) pasquetorum Righetti & Thomas, 2002 by the combination of the following characteristics: (i) more than one short, stout bristle at the tip of segment II of the maxillary palp and (ii) a well-developed paracercus. However, the new species clearly differs from all congeners of the Baetis alpinus species group primarily by the (a) structure of mouthparts-with 14-18 long submarginal setae arranged in a single irregular row on the dorsal surface of the labrum; 2-6 short, stout bristles at the tip of segment II of the maxillary palp; and segment II of the labial palp without a considerably developed apico-internal lobe); (b) setation of abdominal terga, with a few triangular-shaped scales sparsely scattered near the posterior margin only; and (c) a well-developed paracercus, comprised of more than 50 segments. Primary data on the biology and distribution of this new species are provided, and molecular affinities are verified by the analysis of COI (barcode) sequences. Detailed notes on the distribution of mayfly species belonging to the Baetis alpinus species group common in Western Europe and the western part of North Africa are presented. The historical movement of Baetis representatives between Europe, North West Africa, and subsequently Algeria, with the land bridges 'Strait of Gibraltar' and 'Strait of Sicily' as colonization routes, is discussed in detail and identified in the present study as the Western Algeria colonization path and Eastern Algeria colonization path, respectively.

Description of a new species of the genus Awaous Valenciennes, 1837 (Gobiiformes: Oxudercidae) from the middle stretch of the Mahanadi River, Odisha, India, with comments on the Awaous species from India.

A new species of the genus Awaous (Oxudercidae), Awaous motla sp. nov., is described based on 18 specimens collected from the Mahanadi River near Sonepur, Subarnapur District, and 3 specimens from the same river near Boudh bridge, Boudh District of Odisha, India. This species is distinct from its congeners by having a combination of characteristics: relatively small eyes, diameter of 6.6-8.4 in head length (LH); robust and long snout, 2.0-2.6 in LH; eye diameter 2.7-4.1 in snout length; cephalic sensory pore system interrupted with eight pores; predorsal scales 13-15; longitudinal scale series 55-58; gill rakers 2 + 1 + (6-7) on the first gill arch; teeth small, conical, and in a single row on the upper jaw and multiserial (2-3) on the lower jaw. This species is also differentiated from some of its congeners in the nucleotide composition of the cytochrome c oxidase I gene by 8.3%-13.8% Kimura two-parameter (K2P) distance and belongs to a separate cluster in the maximum likelihood tree analysis. This finding is also supported by the species delimitation analysis based on Assemble Species by Automatic Partitioning. The new species holds high commercial value in its locality and needs special conservation attention for sustainable utilization.

Experimental Study on Energy Dissipation Performance of SPA Shear Plate Metal Damper Based on Jacket Platform

Aiming at the problem of excessive vertical vibration caused by seismic primary waves in jacket structures located in seismic zones in China, a new type of shear plate metal damper with upper and lower elliptical openings (SPA) is proposed in this paper. The seismic model test is carried out to compare the shear plate metal damper with three traditional opening forms, central elliptical opening, single row opening, and double row opening, and the hysteretic curve, skeleton curve, and cyclic hysteretic energy dissipation capacity are analyzed. The results show that the energy dissipation performance of the new shear plate metal damper with upper and lower elliptical openings proposed in this paper is better than that of the other three types of dampers.

Two new species of small‐bodied pachycephalosaurine (Dinosauria, Marginocephalia) from the uppermost Cretaceous of North America suggest hidden diversity in well‐sampled formations

AbstractHere we report two new small‐bodied pachycephalosaurines: one from the Dinosaur Park Formation of Alberta and the other from the Hell Creek Formation of Montana, each represented by an isolated squamosal. These two new specimens are approximately the same size as squamosals of Sphaerotholus buchholtzae, and possess several overlapping morphologies with the genus (such as a strongly posteroventrally projecting and laterally tapering parietosquamosal bar). Therefore, these two new specimens are identified as belonging to the genus Sphaerotholus. However, a suite of characters and combinations differentiate these two new specimens from the other three Sphaerotholus species. Most notably, they possess multiple posterior and lateral node rows on the squamosal, and lack a parietosquamosal node (a single row and a parietosquamosal node define these other species in the genus). Specifically, the Alberta specimen possesses two posterior and two lateral node rows, whereas the Montana specimen has three of each. This analysis provides phylogenetic support for the evolutionary hypothesis that a single‐rowed and parietosquamosal node‐less taxon underwent a cladogenetic event that gave rise to a single‐rowed and parietosquamosal node‐bearing lineage and a multi‐rowed, parietosquamosal node‐less lineage (the two taxa described herein). In turn, these two Sphaerotholus lineages possibly underwent anagenetic change throughout the latest Maastrichtian. Additionally, these new taxa suggest that while large‐bodied taxa from well sampled formations are to be found with decreasing frequency, the inverse holds true for small‐bodied taxa and that pachycephalosaurines were more diverse than previously recognized, and continued to diversify up until the very end of the Cretaceous.

Simulation of the Impurity Absorption from a Laminar Flow in a System of Hollow-Fiber Membranes

The external stationary flow of a viscous incompressible fluid and the convective-diffusion mass transfer of a solute in an ordered system of parallel hollow fiber membranes arranged normally to the flow direction are calculated in the ranges of Reynolds numbers \(\operatorname{Re} \) = 0.01–100 and Schmidt numbers \({\text{Sc}}\) = 1–1000. The Navier–Stokes equations and the equation of convective diffusion were solved using the methods of computational fluid dynamics with a no-slip boundary condition and with a constant solute concentration condition on the outer surface of the streamlined fiber. The calculations were performed for a row of fibers and for a multi-fiber system consisting of four and sixteen rows of fibers. The outlet concentrations and the fiber solute retention efficiencies \(\eta \) were calculated depending on the packing density of the fibers and the \(\operatorname{Re} \) and \({\text{Sc}}\) numbers. It is shown that it is possible to use the fiber solute retention efficiency \(\eta \) defined for a single row of fibers to predict the retention efficiency of an extended multi-row fibrous bed.

Effects of tree species and planting density on the total yield of an agroforestry system in the Brazilian Cerrado

ABSTRACT This study aimed to evaluate the effects of spacing and population density of three tree species on the primary yield of an agroforestry system in the Cerrado. The experiment was conducted in the experimental area of the State University of Goiás, São Luís de Montes Belos, Brazil. The experiment was designed to assess the effects of tree species, density, and spacing in a factorial scheme of 3 × 2 × 3, totaling 18 treatments with two tree rows each. The tree species assessed were Corymbia citriodora (seedlings), Eucalyptus cloeziana (seedlings), and an Eucalyptus urophylla clone. The trees were planted in single and triple rows (Trees planted in single and triple rows, varying density). In the first year of the experiment, maize (Zea mays) and Crotalaria juncea were sown, maize and Marandu palisadegrass (Uroclhoa brizantha cv. Marandu) in the second year, and a monoculture of Marandu palisadegrass during the third and fourth years. Due to the larger tree-covered area, the arrangement in triple rows reduced maize yield by 36% in the first year, silage yield by 40% in the second year, and pasture yield by approximately 30%. Reducing tree density is crucial to ensure the functionality of the agroforestry system.

Ultrastructural and immunofluorescence features of the epidermal cells and its secretory granules in the amphioxus Branchiostoma lanceolatum L.

Background and purpose: In the vertebrate family, the epidermis of terrestrial animals is keratinized while in aquatic forms and amphibians can produce mucus. Amphioxus, a cephalochordate, is an important animal model in the study of chordate phylogeny. Major cytoskeletal and extracellular matrix proteins in epidermal cells of amphioxus (Branchiostoma lanceolatum L.) were investigated using transmission electron microscopy and immunofluorescence. Materials and methods: Amphioxus specimens were fresh caught in the Adriatic Sea. Tissue samples were fixed and prepared for transmission electron microscopy and immunofluorescence techniques. Results: The epidermis consisted of one-layered columnar epithelium. Epithelial cells contained voluminous nucleus, a well-developed supranuclear Golgi apparatus, abundant vesicles and apical secretory vesicles surrounded by cytokeratin filaments. A single row of smaller vesicles also appeared close to the basal cell membrane. Strong positive immunolocalization of hyaluronic acid and collagen type I was observed in the apical domain of the plasma membrane of amphioxus, respectively. The positive signal of hyaluronan and collagen proteins referred to the secretory granules in the apical domain of the epidermal cell. Strong positive labelling of aggrecan was seen around the cell nucleus, deep below the apical domain, suggesting that aggrecan is not located in the secretory granules. A strong signal of the cytokeratin 10 protein was seen throughout the cytoplasm of the epidermal cells. Conclusion: Due to its morphology and histochemical composition, epidermal cells of amphioxus may contribute to course surface protection and the mucous layer in amphioxus may serve as a physical barrier between the body and its environment.

Photovoltaic panel’s angle optimization for a better reflected irradiation collection using empiric data and Excel functions approximation

There are many unused surfaces (places) where is practical to install PV panels and still there is a lack of research in this domain. That is why this article presents research for a single row, from W-E, PV panels module output at different installation angle for a better indirect radiation collection, in special areas, like: roof, water-surface and shore. It contains experimental data correlated with simulation data.

Single-row versus double-row arthroscopic repair in the treatment of rotator cuff tears. A systematic review.

The purpose of this study is to perform a systematic review of the scientific literature to compare single and double row techniques for rotator cuff tears in terms of functional, pain improvement and structural healing of the tendon. In order to carry out the research, a systematic selection of scientific articles has been made by consulting PubMed and The Cochrane Library databases. The articles included in the present study compare the single-row and double-row techniques, with publication date between 2016 and 2021. Diverse results are observed in the UCLA, SST, Constant and ASES assessment scales and in the range of mobility, therefore, the superiority of one technique in terms of functional results is not established. The double row technique may show superiority in the strength variable, although there is a methodological variability in its measurement. The double-row technique may be related to more intense postoperative pain, while the single-row technique to residual shoulder pain. However, the variables strength and pain show non-homogeneous or coincident data. The superiority of the double row repair in the structural healing of the tendon and a lower re-tear rate than the single row technique is established with statistically significant results, being the most homogeneous and coincident studies.

FE MODELLING FOR CAPACITIES OF HEADED STUD SHEAR CONNECTORS IN COMPOSITE STEEL BEAMS WITH SLABS CONCRETE

This study discusses the overall performance of the behavior the shear stud in the composite steel beam. The work has been modeled by using ANSYS APDL program. Under of the influence of lateral horizontal pressure. The analyzed structure is a composite of beam-slab. The beam section is (254 X 254 X 73 kg/m) with slab of (1600 mm length, 1200 mm width and 150 mm height) and 6 headed studs 19mm diameter with 100 mm high featuring a single row of pointed studs spaced at 150 mm intervals. First, the study was placed on 200 mm from the end of the slabs on both sides. Headed studs and the value of the limited load are the most relevant dimensions for the aims of this study. One parameter was changed which was the load value. The resulted composite steel was analyzed for each change in the parameters. The results were compared to those from the experimental which revealed a possible alternate analysis that included the selected changes. Besides, the Von-mises stresses and stress intensity have been studied. It was found through structural analysis that there were stresses in the area of the studs which they are resistance to horizontal slips caused by lateral pressure loading. Four composite steel were evaluated at each parameter and were checked with the other factors. For this aim a utilizing parametric analysis software using ANSYS. Language of Design (APDL) was constructed to examine the behavior of the structure.

Comparative study on flexural behavior of steel-UHPC composite beams and steel-ordinary concrete composite beams in the negative moment zone

To compare the flexural behavior of steel-UHPC (ultra-high performance concrete) composite beams and steel-ordinary concrete composite beams under a negative bending moment, 4 steel–concrete composite beams were tested under a negative bending moment. The effects of slab materials and stud number on flexural failure mode, crack development, stiffness ductility, cracking load and ultimate flexural capacity of composite beams were investigated. The results show that the UHPC can significantly improve the flexural behavior of steel–concrete composite beams under a negative bending moment. For the steel-UHPC composite beams with a single row, the cracking load is 135 % higher than that of steel-ordinary concrete composite beams, and the overall stiffness increased by 108 %, the yield stiffness increased by 40 %, the ultimate flexural capacity increased by 9 %, and the ductility increased by 133 %; for the steel-UHPC composite beams with double row, the cracking load is 102 % higher than that of the steel-normal concrete composite beam, the overall stiffness is increased by 34 %, the yield stiffness is increased by 44 %, the ultimate flexural capacity is increased by 6 %, and the ductility is increased by 75 %. Increasing the number of studs can significantly improve the overall ductility of composite beams, while the improvement of cracking load, overall stiffness, and ultimate flexural capacity of composite beams is not significant. The cracking load, overall stiffness, yield stiffness, ultimate load, and ductility of double-row stud steel–concrete composite beams are 23 %, 53 %, 13.2 %, 12 %, and 115 % higher than those of single-row stud steel–concrete composite beams, respectively; while those of double-row steel-UHPC composite beams increases by 6 %, 8 %, 16 %, 8 % and 62 % higher than those of single-row stud steel–concrete composite beams, respectively. A simplified calculation model for the flexural capacity of steel-UHPC composite beams in a negative moment zone was established.