Single Row Research Articles

Modeling the performance of a single rotor row in a turbomolecular pump using the TPMC method: effects of operational and geometric variables

Modeling the performance of a single rotor row in a turbomolecular pump using the TPMC method: effects of operational and geometric variables

EARLY RESULTS OF GLUTEAL CUFF RECONSTRUCTION AND AUGMENTATION

Gluteal Tendinopathy is a poorly understood condition that predominantly affects post-menopausal women. It causes lateral hip pain, worse when lying on the affected side or when walking up a hill or stairs. It has been labelled ˜Greater Trochanteric Pain Syndrome” a name that recognises the lack of understanding of the condition.Surgical reconstruction of the gluteal cuff is well established and has been undertaken numerous times over the last 16 years by the senior author (AJL). However, the quality of collagen in the tendons can be very poor and this leads to compromised results. We present the results of gluteal cuff reconstruction combined with augmentation using a bioinductive implant.14 patients (11 female, 3 male; mean age 74.2 ± 6.3 years) with significant symptoms secondary to gluteal tendinopathy that had failed conservative treatment (ultrasound guided injection and structured physiotherapy) underwent surgical reconstruction by the senior author using an open approach. In all cases the iliotibial band was lengthened and the trochanteric bursa excised. The gluteal cuff was reattached using Healicoil anchors (3–5×4.75mm anchors; single anchors but double row repair) and then augmented using a Regeneten patch. Patients were mobilised fully weight bearing post-operatively but were asked to use crutches until they were no longer limping. All had structured post-surgery rehabilitation courtesy of trained physiotherapists.There were no post-operative complications and all patients reported an improvement in pain levels (Visual Analogue Scale 7.8 pre-op; 2.6 post-op) and functional levels (UCLA Activity Score 3.5 pre-op; 7.1 post-op) at 6 months post surgery.Surgery for gluteal tendinopathy produces good outcomes and the use of Regeneten as an augment for poor quality collagen is seemingly a safe, helpful addition. Further comparative studies would help clarify this.

Early ray‐finned herbivores: the dental system of Eurynotoidiidae (Actinopterygii; middle–late Permian, European Russia) and implications for palaeobiology and palaeoecology

AbstractEurynotoidiformes are a little‐known group of actinopterygian fishes from the Permian of European Russia, characterized by the possession of multicuspid marginal teeth arranged in a single row. Morphologically, the teeth resemble those of Recent Cichlidae, Acanthuridae, Siganidae or Serrasalmidae, suggesting similar trophic adaptations related to herbivory. Tooth histology is similar to the majority of basal actinopterygians (composed of dentine, acrodin and collar enamel). Teeth are ankylosed in their attachment, and labial pleurodont in implantation, strengthening the tooth. The multicuspid tooth crowns derive from conical teeth of predatory or omnivorous ancestors, analogous to the evolution of multicuspid teeth in cichlid fishes. Tooth replacement in eurynotoidiforms is most comparable to an alternating pattern, with a possible simultaneous, unilateral replacement occurring in the whole jaw, similar to characiform fishes. Replacement teeth were formed extraosseously. Teeth of the inner dental arcade were conical. Based on comparisons with the teeth of extant actinopterygians specialized for herbivory, along with functional morphological analysis and consideration of wear patterns, we hypothesize that eurynotoidiforms represent the oldest known actinopterygians specialized for herbivory. Several strategies of herbivory in Recent actinopterygians were already realized by eurynotoidiforms as early as the Late Palaeozoic (middle and late Permian): grazing/cutting filamentous algae (Lapkosubia spp., Isadia suchonensis), browsing/biting off macrophyte fragments (Isadia aristoviensis), scraping/harvesting periphyton from hard substrates (Isadia opokiensis, I. arefievi). However, notable morphological differences in the jaws (elongate) and tooth arrangement (homodont along the jaw, functional teeth separated) suggest that this Permian experiment in herbivory followed different pathways compared to extant taxa.

Effect of plant density on total oil quality and fatty acid compositions in peanut (Arachis hypogaea L.) cultivars

Research in the Eastern Mediterranean Transition Region of Türkiye has demonstrated that plant density impact yield of peanut (Arachis hypogaea L.) cultivars differentially. It is suspected that interactions of plant density and cultivar could also impact oil quality and fatty acid composition when grown in this region. This topic has not been addressed in the country; therefore, the objective of this research was to determine if plant density can affect those variables. The study was conducted in 2020 and 2021 in the zone of Osmaniye to determine total oil content of kernels, and contents of oleic acid, palmitic acid, arachidonic acid, linoleic acid, stearic acid, and lignoceric acid, as well as iodine value and oleic/linoleic ratio for the cultivars Halisbey, Rigel, Aysehanım, NC 7, and Masal. Plant response was in most instances different regardless of plant populations made up of a single row planting pattern with rows spaced 70 cm apart (95.000 plants ha-1) compared with a twin row planting pattern with rows spaced 20 cm apart on 90 cm centers with an intra-row distance of 15 cm (148.000 plants ha-1). It is concluded that no differences in oil quality and fatty acid composition were noted when comparing cultivars established at various combinations of planting pattern and plant population, but there were notable differences among the cultivars.

Optimal design and experiment of bionic vacuum suckers with high attachment properties

A variety of bionic vacuum suckers with papillae structures of different parameters were developed to improve the attachment performance of vacuum suckers. The oral sucker of the suckermouth catfish served as the bionic prototype and bionic suckers were made by taking the diameter of papillae, the number of single rows of papillae, the center distance between adjacent rows of papillae, and the distance between the outermost row of papillae and the edge as influencing factors. The single-factor tests and response surface tests were carried out respectively with the growth rates of vertical and horizontal attachment forces as the response values. Twenty-five groups of bionic suckers and one group of standard suckers were fabricated and tested for attachment forces. The experimental results revealed that the bionic suckers had higher vertical and horizontal attachment forces than standard suckers and that their maximum growth rates for these forces were 5.16% and 59.87%, respectively. This suggested that the bionic suckers had better attachment performance. The significant orders of the factors affecting response values were established and their interaction was also analyzed. Besides, the optimal parameter combination of papillae structures of the bionic suckers with optimal vertical and horizontal attachment properties was obtained, respectively. Finally, the influence mechanism of papillae structures on the attachment properties of bionic suckers was analyzed. The studies can serve as a guide for the application of bionic suckers in agricultural production areas such as fruit picking and handling, and the improvement of attachment performance of associated machinery.

Morphological and molecular description of a new species of sandfly, Sergentomyia (Neophlebotomus) ashwanii sp. nov. (Diptera: Psychodidae) from Western Ghats, India

Objective: To report a new species of sandfly, Sergentomyia (Neophlebotomus) ashwanii sp. nov. (Diptera: Psychodidae) from Western Ghats, India. Methods: A systematic sandfly survey was conducted in the Thrissur and Kollam districts of Kerala, India using mechanical aspirators, light and sticky traps, both indoor and outdoor habitats, for a period of one year. Deoxyribonucleic acid barcoding of samples was performed targeting mitochondrial cytochrome oxidase I (COI) gene and sequence generated was subjected to phylogenetic analysis. Results: Sergentomyia (Neophlebotomus) ashwanii, a new sandfly species is recorded and described in this communication. A single row of 10-12 pointed teeth in the cibarium with 4-6 small denticles or fore-teeth are the key characteristics that is distinctive from other members of the subgenus Neophlebotomus. Mitochondrial COI barcode followed by phylogenetic analysis of the nucleotide sequence confirms that specimens of the species belong to the same taxonomic group while the genetic distance (14.2%) with the congeners established it to be a different species. Conclusions: The Western Ghats' being an important biodiversity hotspot and has dearth of systematic entomological surveys on sandflies. The current study tried to fill the void and also report a new sandfly species.

Research on the Effect of Structural Parameters on Cavitation Performance of Shear Hydrodynamic Cavitation Generator

The method of cavitation is increasingly applied in water environmental protection. Based on the numerical simulation method, a study on the structural parameters of the shear-type hydrodynamic cavitation generators for wastewater treatment is proceeded. The internal flow field is described by employing the mixed multiphase flow model and the Zwart cavitation model. Experiments were conducted by applying the wastewater from a dyeing factory as the medium. The degradation rate of COD in water characterizes the cavitation performance of the hydrodynamic cavitation generator, and the rationality of the numerical simulation approach is validated. The findings indicate that different structural parameters have a great influence on the cavitation performance. The appropriate number of tooth rows creates a flow field with a greater vapor and velocity than the other parameters. The number of teeth in a single row, the outer diameter of the hydrodynamic cavitation generator and the tooth bevel angle also affect the cavitation performance to some extent, and there is an optimal value. The study provides a reference for the applicability of a numerical simulation of the flow field inside the hydrodynamic cavitation generator and the structural optimization of the rotary hydrodynamic cavitation generator.

Pseudo-static analysis of 3D unsaturated bench slopes stabilized by multiple rows of piles

Bench slopes incorporated with multiple rows of anti-slide piles remain an effective technique in landslide disaster preventions and are widely employed in the design of new subgrades and embankments. To provide more realistic results for engineering guidance, the three-dimensional (3D) effect and suction in soils require explicit considerations. Employing the upper bound limit analysis method, a 3D limit analysis of bench slopes stabilized by multiple rows of piles is performed in this paper. The upper bound solutions of several illustrative slopes are optimized and compared with the published ones, indicating the validity of the optimization program and the proposed method. A series of parameter analyses are conducted regarding the roles of suction and anti-slide piles in slope safety assessments. The results show that the suction effect and pile reinforcement increase continually as the pile location increases and the influence of bench width can be ignored. The stability of bench slopes stabilized by multiple rows of piles differ with that of slopes stabilized by single row of piles dramatically. The maximum pile reinforcement reaches 70% for sandy soil slopes but only 30% for clayey soil slopes. The influences of surcharge load and seismic load on the pile reinforcement can nearly be neglected.

SDEWES 2023: Barriers and Possibilities for the Development of Short-Rotation Coppice as an Agroforestry System for Adaptation to Climate Change in Central European Conditions

This article compares different production, economic, and selected environmental aspects of agroforestry systems in a standard (alley cropping) and a newly proposed design with fast-growing trees grown in short-rotation coppice. Our models of agroforestry systems (AFSs) are as follows: (i) alley cropping AFS with cherry and walnut trees in single rows (tree strips) with 28 m-wide arable fields between them (crop strips), and (ii) coppiced tree belt AFS with poplars and willows and 25 m-wide arable fields between them (crop strips). To evaluate the production characteristics of trees, we used yield curves from experimental plantations in conditions of the Czech Republic from previous research projects. Cost data were collected from long-term experimental plantations and combined with current operation and energy prices. The article presents an economic methodology for assessing the competitiveness of biomass production in AFSs under the current identified market conditions. Our results show that AFSs with short-rotation coppice can have similar economic and production results as annual crops if grown on suitable sites and with appropriate quality of agronomy. In comparison, alley cropping AFSs with fruit trees would not be economically viable for farmers without a significant subsidy for establishment and maintenance in the first years after establishment. Concerning the latest economic and political developments, the product from SRC (energy woodchips) can be evaluated as strategic, increasing the producer’s independence from purchased energy fuels.

Biocomposite Anchors Have Greater Yield Load and Energy Compared With All-Suture Anchors in an In Vitro Ovine Infraspinatus Tendon Repair Model

PurposeTo compare tensile fatigue and strength measures of biocomposite and all-suture anchors in an ovine humerus-infraspinatus tendon model of rotator cuff repair. MethodsInfraspinatus tendons on adult ovine humeri were sharply transected at the insertion. One of each pair was randomly assigned for fixation with two biocomposite or all-suture anchors. Constructs were tested with 200 cycles of 20-70 N tensile load and gap formation was measured at the incised tendon end every 50 cycles. They were subsequently tested to failure. Outcome measures including fatigue stiffness, hysteresis, creep and gap formation, and tensile stiffness, and yield and failure displacement, load, and energy were compared between anchors. ResultsBiocomposite anchors had higher yield load (134.1 ± 6.5 N, p<.01) and energy (228.6 ± 85.7 J, p<.03) than all-suture anchors (104.7 ± 6.5 N, 169.8 ± 85.7 J). Fatigue properties were not different between anchors, but stiffness and gap formation increased and hysteresis and creep decreased significantly with increasing cycle number. ConclusionsWhile the yield displacement of both anchors was within the range of clinical failure, the tensile yield load and energy of ovine infraspinatus tendons secured to the humerus with two single-loaded all-suture anchors in a single row were significantly lower than those secured with two biocomposite anchors in the same configuration. Clinical RelevanceIt is important to understand the biomechanical properties for selecting anchors for rotator cuff repair. A direct comparison of fatigue testing followed by failure strength of infraspinatus tendon fixation with all-suture and biocomposite anchors could help guide anchor selection and post-operative mobility recommendations.

Design of a Self-propelled Single Row Zero-till Pea Planter for Hills

A self-propelled single row zero-till pea planter was designed for use in hill agriculture in North-east India. An inverted T-type 30 mm wide furrow opener was designed to cut and open the untilled clay soil for planting seeds. The power required to cut the soil and overcome rolling resistance were determined for the design of the furrow opener. A vertical plate seed metering device with positive seed knockout device suitable for pea seeds was used in the planter. The seed hopper was designed to cover an area of 1000 m2 in one filling. A pair of steel rollers was designed to maintain an uniform depth of furrow and covering seeds with soil. A ground wheel was designed to provide power to the seed metering shaft. Accessories, namely the handle, wheels and shaft assembly, main frame and vertical frame were designed for better performance of the planter. The power transmission system was also designed with a belt-tension-type clutch and gearbox to transfer power from the engine to the wheels. A 6.5 kW IC petrol engine was used as a power source. The designed planter was fabricated, and performance of the planter was evaluated under actual field condition using pea seeds at two forward speeds of 0.59 and 0.67 m.s-1 at 60 mm depth of planting. The average seed-to-seed spacing and depth of seed placement were 105.7 mm and 42.5 mm, respectively. The planter could cover an area of 0.06 ha.h-1 with 75.3% field efficiency.

Genetic improvement of Egyptian cotton (Gossypium barbadense L.) for high yield and fiber quality properties under semi arid conditions

Between 2016 and 2018, the Agriculture Research Center's Sakha Agriculture Research Station conducted two rounds of pedigree selection on a segregating population of cotton (Gossypium barbadense L.) using the F2, F3, and F4 generations resulting from crossing Giza 94 and Suvin. In 2016, the top 5% of plants from the F2 population were selected based on specific criteria. The superior families from the F3 generation were then selected to produce the F4 families in 2017, which were grown in the 2018 summer season in single plant progeny rows and bulk experiments with a randomized complete block design of three replications. Over time, most traits showed increased mean values in the population, with the F2 generation having higher Genotypic Coefficient of Variance (GCV) and Phenotypic Coefficient of Variance (PCV) values compared to the succeeding generations for the studied traits. The magnitude of GCV and PCV in the F3 and F4 generations was similar, indicating that genotype had played a greater role than the environment. Moreover, the mean values of heritability in the broad sense increased from generation to generation. Selection criteria I2, I4, and I5 were effective in improving most of the yield and its component traits, while selection criterion I1 was efficient in improving earliness traits. Most of the yield and its component traits showed a positive and significant correlation with each other, highlighting their importance in cotton yield. This suggests that selecting to improveone or more of these traits would improve the others. Families number 9, 13, 19, 20, and 21 were the best genotypes for relevant yield characters, surpassing the better parent, check variety, and giving the best values for most characters. Therefore, the breeder could continue to use these families in further generations as breeding genotypes to develop varieties with high yields and its components.

Predicting turbulent wake flow of marine hydrokinetic turbine arrays in large-scale waterways via physics-enhanced convolutional neural networks

We present a physics-enhanced convolutional neural network (PECNN) algorithm for reconstructing the mean flow and turbulence statistics in the wake of marine hydrokinetic (MHK) turbine arrays installed in large-scale meandering rivers. The algorithm embeds the mass and momentum conservation equations into the loss function of the PECNN algorithm to improve the physical realism of the reconstructed flow fields. The PECNN is trained using large eddy simulation (LES) results of the wake flow of a single row of turbines in a virtual meandering river. Subsequently, the trained PECNN is applied to predict the wake flow of MHK turbines with arrangements and positionings different than those considered during the training process. The PECNN predictions are validated using the results of separately performed LES. The results show that the PECNN algorithm can accurately predict the wake flow of MHK turbine farms at a small fraction of the cost of LES. The PECNN can improve the accuracy by around 1% and reduce the physical constraint indices by around 50% compared to the CNN without physical constraints. This work underscores the potential of PECNN to develop reduced-order models for control co-design and optimization of MHK turbine arrays in natural riverine environments.

Cost Minimization for Equilibrium Transition

In this paper, we delve into the problem of using monetary incentives to encourage players to shift from an initial Nash equilibrium to a more favorable one within a game. Our main focus revolves around computing the minimum reward required to facilitate this equilibrium transition. The game involves a single row player who possesses m strategies and k column players, each endowed with n strategies. Our findings reveal that determining whether the minimum reward is zero is NP-complete, and computing the minimum reward becomes APX-hard. Nonetheless, we bring some positive news, as this problem can be efficiently handled if either k or n is a fixed constant. Furthermore, we have devised an approximation algorithm with an additive error that runs in polynomial time. Lastly, we explore a specific case wherein the utility functions exhibit single-peaked characteristics, and we successfully demonstrate that the optimal reward can be computed in polynomial time.

Dynamics of soil penetration resistance, moisture depletion pattern and crop productivity determined by mechanized cultivation and lifesaving irrigation in zero till blackgram

Rice fallow black gram is grown under the residual moisture situation as a relay crop in heavy texture montmorillonite clay soil under zero till condition. Since the crop is raised during post monsoon season, the crop often experiences terminal stress due to limited water availability and no rainfall. Surface irrigation in montmorillonite clay soil is determent to pulse crop as inundation causes wilting. Therefore, zero tilled rice fallow black gram has to be supplemented with micro irrigation at flowering stage (35 days after sowing) to alleviate moisture stress and to increase the productivity as well. Hence micro farm pond in a corner of one ha field was created to harvest the rain water during monsoon season and the same was utilized to supplement the crop with lifesaving irrigation through mobile sprinkler at flowering stage for the crop grown under conservation agriculture. Soil cracking is also the common phenomena of montmorillonite clay soil where evaporations losses would be more through crack surfaces. The present study was therefore conducted to study the changes in the soil physical properties, crop establishment and productivity in conjunction with mechanized sowing and harvest and supplemental mobile sprinkler irrigation. Sowing of black gram by broadcasting 10 days prior to the manual harvest of rice, manual drawn single row seed drill after the machine harvest of rice and sowing by broadcasting at 4 days prior to machine harvest of rice was experimented separately and in combination with lifesaving irrigation. Results indicated that the number of wheel passes and lifesaving irrigation had a very strong impact on soil penetration resistance and soil moisture. Combined harvester followed by no till seed drill increased the soil penetration resistance in all the layers (0–5 cm, 5–10 cm and 10–15 cm). Two passes of wheel increased the mean soil penetration resistance from 407 KPa to 502 KPa. The soil penetration resistance (0–5 cm) at harvest shown that black gram sown by manual broadcasting 10 days prior to manual harvest of paddy supplemented with life irrigation on 30 DAS reduced the soil penetration resistance from 690 Kpa to 500 Kpa, 740 Kpa to 600 Kpa and 760 Kpa to 620 Kpa respectively at 0–5 cm, 5–10 cm and 10–15 cm layer. In general, moisture depletion rate was rapid in the surface layer of 0–5 cm as compared to other layers of 5–10 cm and 10–15 cm up to 30 DAS (Flowering stage). The moisture content and the soil penetration resistance had an inverse relationship. The soil penetration resistance also had an inverse relationship with the root length in which the root length lowers as the soil penetration resistance increases. The soil crack measured at 60 DAS was deeper with no till seed drill (width of 3.94 cm and depth of 13.67 cm) which was mainly due to surface layer compaction. The relative water content, specific leaf weight and chlorophyll content were significantly improved through the supplemental irrigation given on 30 DAS irrespective of crop establishment methods. The results further indicated that compaction of ploughed layer in the moist soil due to combined harvester and no till seed drill had a negative impact on yield (457 kg ha−1), which was improved by 19.03 per cent due to increased soil moisture with supplemental irrigation. The mean yield increase across different treatments due to supplemental lifesaving irrigation through mobile sprinkler was 20.4 per cent.

Assessing the effect of cultural practices on Mississippi corn production: 2. Grain composition

AbstractGlobal demand for corn (Zea mays L.) is increasing, and it remains one of the most consumed crops by both humans and animals due to its high calorie content. However, corn grain quality research is sparse and often focused only on a few selected influencing factors. Therefore, two side‐by‐side studies (Addition and Deletion) were conducted in 2020 and 2021 in Mississippi to assess the grain composition including protein, starch, oil, and moisture of corn under several management practices. A randomized complete block design was implemented in both experiments involving a complete factorial of three factors including two plant populations (32,000 and 40,000 seed acre−1), two‐row configurations (single and twin), and six combinations of nutrients plus fungicide application (NF). The trials differed based on the manner of NF applications. In the trial termed Addition, all NF treatments were added incrementally, whereas in the Deletion trial they were withheld in a stepwise manner. Conditional inference tree analysis was conducted to examine interaction effects among the three factors over 3 site‐years. Corn protein content ranged between 8.2% and 9.8% across all years and locations. All three factors and certain interactions significantly influenced both protein and starch content. Specifically, single row planting, 40,000 seeds acre−1, and higher rates of N resulted in higher protein content. Contrarily, the starch content was positively influenced by twin row, 32,000 seeds acre−1 and only N application. Single row configuration resulted in higher oil than twin rows. This study determined that different management factors have the potential to positively influence protein, starch, and oil. These management strategies could extend farmers profitability and provide superior products for industrial purposes with additional implications for livestock feed supplements.

Analyzing Unsteady Turbomachinery Flow Simulations With Mixing Entropy

Abstract The prediction of unsteady aerodynamic loads is a central problem during the design of turbomachinery. Over the last 20 years, harmonic balance methods have been shown to be highly efficient for this task. A CPU-cost optimal setup of a harmonic balance simulation, however, requires knowledge of relevant harmonics. In the case of a single blade row with a periodic disturbance this question amounts to the classical problem of harmonic convergence, a problem which is solely due to the nonlinearity of the unsteady flow physics. In contrast, for multi-stage configurations, the choice of harmonics is further complicated by the fact that the interactions of disturbances with blade rows may give rise to a vast spectrum of harmonics that possibly have important modal content, e.g., Tyler–Sofrin modes. The aim of this paper is to show that the mixing entropy attributed to circumferential modes of a given harmonic can serve as a disturbance metric on the basis of which a criterion could be derived whether a certain harmonic should be included or not. The idea is based on the observation that the entropy due to the temporal and circumferential mixing of the flow at a blade row interface may be decomposed, up to third-order terms, into independent contributions from different frequencies and mode orders. For a given harmonic balance (and steady) flow result, the mixing entropy attributed to modes that are simply mixed out, rather than resolved in the neighboring row, is shown to be a natural indicator of a potential inaccuracy. We present important features of the mixing entropy for unsteady disturbances, in particular a close relationship to sound power for acoustic modes. The problem of mode selection in a 1.5-stage compressor configuration serves as a practical example to illustrate our findings.

Assessment of Machine Learning Wall Modeling Approaches for Large Eddy Simulation of Gas Turbine Film Cooling Flows: An a Priori Study

Abstract In this work, a priori analysis of machine learning (ML) strategies is carried out with the goal of data-driven wall modeling for large eddy simulation (LES) of gas turbine film cooling flows. High-fidelity flow datasets are extracted from wall-resolved LES (WRLES) of flow over a flat plate interacting with the coolant flow supplied by a single row of 7-7-7 shaped cooling holes inclined at 30 degrees with the flat plate at different blowing ratios (BR). The WRLES are performed using the high-order Nek5000 spectral element computational fluid dynamics (CFD) solver. Light gradient boosting machine (LightGBM) is employed as the ML algorithm for the data-driven wall model. Parametric tests are conducted to systematically assess the influence of a wide range of input flow features (velocity components, velocity gradients, pressure gradients, and fluid properties) on the accuracy of ML wall model with respect to prediction of wall shear stress. In addition, the use of spatial stencil and time delay is also explored within the ML wall modeling framework. It is shown that features associated with gradients of the streamwise and spanwise velocity components have a major impact on the prediction fidelity of wall model, while the effect of gradients of wall-normal velocity component is found to be negligible. Moreover, adding flow feature information from an x-y-z spatial stencil significantly improves the ML model accuracy and generalizability compared to just using local flow features from the matching location. Overall, highest prediction accuracy is achieved when both spatial stencil and time delay features are incorporated within the data-driven wall modeling paradigm.

Arthroscopic Modified Double-Pulley Suture-Bridge Repair of Medium-Sized Supraspinatus Tendon Tears

At present, the repair patterns for medium-sized supraspinatus tendon tears are double- and single-row repairs. However, the limitations of double-row repair include excessive anchor implantation and incremental surgical cost and time, whereas a deficient tendon-bone contact area exists with single-row repair. The modified double-pulley suture-bridge repair presented in this study is an arthroscopic technique using 3 double-loaded suture anchors combined with a double-pulley technique to form a hybrid repair pattern with a double row as the mainstay and a single row as the supplement. In the treatment of medium-sized tendon tears, the modified double-pulley suture-bridge repair can not only maximize the tendon-bone contact area but also lower the surgical cost and shorten the operative time. The surgical technique is described, including pearls and pitfalls, as well as advantages and disadvantages.

Experimental study on the effect of partial shear studs layout on flexural behavior of steel-concrete composite beams

In steel-concrete composite beams, partial shear connection offers advantages including greater ductility and lower cost. However, partial shear connection constraints on composite beam structural performance, such as reduced beam stiffness, increased steel-concrete interface slip, etc., should not be neglected. Several researches have revealed that shear connector layout is one of the main approaches to limit partially composite beam vulnerability. Shear connector layout optimization has not been completely investigated experimentally, and its effect on composite beam structural performance is still unknown. This paper focusses on the experimental study of the effect of shear connectors layout on the flexural performance of composite beams. It reports the optimization of the layout of shear connectors based on blocked distribution of shear connectors laid in a single row, while concentrating the highest number of shear studs towards the supports of a simply supported composite beam. A fully composite beam with normal layout of shear studs was tested as control specimen, while the rest of the beams used partial shear connection (η = 0.5). Beams with partial shear connection had 3 different layouts of shear studs. The first had uniformly distributed shear studs, and the rest had shear studs laid out in 2 and 3 blocks each of uniform spacing respectively. The results showed that the beam with 3 blocks layout each of equal spacing of shear studs had the closest best structural performance to the fully composite beam and had better ductility than the latter.