Large Diameter Research Articles

Design and control of a parallel-axis twin-rotor counter-rotating marine current turbine for the shallow sea conditions

The ocean contains a large amount of marine current energy which is considered to be one of the most promising renewable energy sources for commercialization. In contrast to the high-velocity currents in straits close to the mainland or islands, the velocities of the currents in most of the sea are low. The exploitation of low-velocity currents is of great significance to the regions with such energy sources. Although the technology for harvesting marine current energy is developing rapidly, the exploitation of low-velocity current energy is often neglected due to its low power density. When the existing marine current turbine (MCT) technology developed for high-velocity currents is used for low-velocity currents, it will result in large rotor diameters and low performance of starting current velocities, which is subject to the water depth and the levelized cost of energy. To solve those problems, a direct-drive parallel-axis twin-rotor marine current turbine (TRMCT) was developed in this research, with a focus on the design of the transmission and generator of the MCT, as well as the improvement of the control strategy. Firstly, the structure of the TRMCT and its characteristics were given. Secondly, the improved optimal torque control strategies for the TRMCT were designed. Finally, to verify the feasibility of the TRMCT and its control strategy, the mathematical model was built and simulated, and the starting performance and operating performance were analyzed. The results show that the proposed TRMCT can start to work at about 0.2 m/s and the conversion efficiency of the whole system can reach about 25%. Compared to the scheme using two identical single-rotor MCTs, the TRMCT's output power can increase by up to 26%. Besides, the torque imbalance caused by the difference in the current velocities on the two rotors can be well coped with.

Research on Dual Fuel Combustion Characteristics of PFI Natural Gas +DI Gasoline in Large Cylinder Diameter Engine

A 3D simulation model of a single cylinder of a natural gas engine was established. PFI natural gas DI gasoline was used to control the time matching between injection and ignition, so that gasoline could form a small active stratified area near the spark plug. The combustion characteristics under different matching conditions were studied, and finally compared with pure natural gas. It is found that gasoline can be used in large cylinder diameter natural gas engine in a small range, which can accelerate the combustion of natural gas fuel, shorten the time used by CA0-CA5 by 77.6%, shorten the time used by CA5-CA90 by 26.5%, and increase the indicated thermal efficiency of natural gas engine by 1.4%.

Distribution status and roost characteristics of Indian Flying Fox Pteropus medius Temminck, 1825 (Mammalia: Chiroptera: Pteropodidae) in Kurukshetra district, Haryana, India

The Indian Flying Fox Pteropus medius plays a major role in the maintenance of a healthy ecosystem and is very specific in selecting roosting sites. The present study was conducted from January 2021 to March 2022 to document the occurrence of roosting colonies, the roosting sites and the population characteristics of P. medius in Kurukshetra district, Haryana. Of the 10 roosting sites identified in four tehsils of Kurukshetra district, 60% were located close to water sources, 20% were near agricultural fields, and the remaining sites were in roadside plantations. Eight roosting sites were observed to be permanent and two were temporary. A total of 233 trees belonging to seven families, eight genera, and nine species were identified as roost trees for this species. Our survey results show that P. medius preferred (77.42%) roosting majorly on trees of the Myrtaceae family (Eucalyptus), while very few individuals (0.5%) were recorded on Phoenix dactylifera. A positive Pearson correlation between the population of the roosting bats and the roost tree characteristics such as height (r = 0.320, p <0.001), dbh (r = 0.226, p <0.001), and circumference (r = 0.293, p <0.001) was also observed. The findings of the current study revealed that P. medius prefers to roost on tall trees with large diameters at breast height, located near water bodies and agricultural fields. Protecting such large and tall trees would benefit the conservation of roosting sites of this species and its populations.

Fishpole Bamboo [Phyllostachys aurea (Andre) Riviere and C. Riviere] in the Philippines: Its Properties and Potential Utilization

This study focused on assessing the morphological, anatomical, and physico-mechanical properties of fishpole bamboo [Phyllostachys aurea (André) Rivière and C.Rivière] grown in Baguio City, the Philippines. The aim of this study was to establish baseline information about these properties and recommend potential applications beyond ornamental use. The results showed that the relative density, modulus of rupture, and stress at the proportional limit of the fishpole bamboo were higher than those of commercial bamboo species. In terms of morphological properties, the culm diameter and culm wall thickness tended to decrease significantly by 64.0 and 39.96%, respectively, toward the top portion. In contrast, the internode length increased significantly from bottom to middle by 41.57%. With respect to anatomical properties, the fiber length, fiber and lumen diameter, and cell wall thickness significantly decreased from bottom to top by 14.89, 13.63, 23.32, and 10.67%, respectively. Conversely, its relative density and radial shrinkage significantly increased by 23.06% and 26.77%, respectively, toward the top. Regarding the mechanical properties, the modulus of rupture, stress at the proportional limit, and modulus of elasticity increased significantly by 62.41, 88.25, and 45.51% from the bottom of the culm to the top, respectively. However, the compressive strength (29.40 MPa) and shear strength (2.83 MPa) deviated from this trend. Fishpole bamboo can be employed as a raw material for furniture, window frames, and handicrafts, wherein a large diameter is not required. Additionally, it can be used for canes, walking sticks, umbrella and fan handles, and souvenir materials. Notably, culms with diameters exceeding 5.0 cm can be used as raw materials for laminated and engineered bamboo. They can also be used as raw materials for preparing pellets and briquettes.

Transrectal ultrasound for intraoperative interstitial needle guidance in cervical cancer brachytherapy

ObjectiveThis study aimed to prospectively assess the visibility of interstitial needles on transrectal ultrasound (TRUS) in cervical cancer brachytherapy patients and evaluate its impact on implant and treatment plan quality.Material and methodsTRUS was utilized during and after applicator insertion, with each needle’s visibility documented through axial images at the high-risk clinical target volume’s largest diameter. Needle visibility on TRUS was scored from 0 (no visibility) to 3 (excellent discrimination, margins distinct). Quantitative assessment involved measuring the distance between tandem and each needle on TRUS and comparing it to respective magnetic resonance imaging (MRI) measurements. Expected treatment plan quality based on TRUS images was rated from 1 (meeting all planning objectives) to 4 (violation of High-risk clinical target volume (CTVHR) and/or organ at risk (OAR) hard constraints) and compared to the final MRI-based plan.ResultsAnalysis included 23 patients with local FIGO stage IB2-IVA, comprising 41 applications with a total of 230 needles. A high visibility rate of 99.1% (228/230 needles) was observed, with a mean visibility score of 2.5 ± 0.7 for visible needles. The maximum and mean difference between MRI and TRUS measurements were 8 mm and –0.1 ± 1.6 mm, respectively, with > 3 mm discrepancies in 3.5% of needles. Expected treatment plan quality after TRUS assessment exactly aligned with the final MRI plan in 28 out of 41 applications with only minor deviations in all other cases.ConclusionReal-time TRUS-guided interstitial needle placement yielded high-quality implants, thanks to excellent needle visibility during insertion. This supports the potential of TRUS-guided brachytherapy as a promising modality for gynecological indications.

Impact of cannula diameter on pregnancy outcomes after minimally invasive fetal laser surgery in the treatment of twin-to-twin transfusion syndrome: A systematic review and meta-analysis.

Preterm prelabor rupture of membranes (PPROM) remains a major complication of fetal laser surgery in the treatment of twin-to-twin transfusion syndrome (TTTS). The aim of the study was to determine the impact of cannula size on pregnancy outcomes, with a particular focus on PPROM. The protocol was developed and registered in the PROSPERO database under registration number CRD42022333630. The PubMed, Web of Science, and EMBASE databases were searched electronically on May 18, 2022, and updated on March 2, 2023, utilizing a combination of the relevant MeSH terms, keywords, and word variants for "TTTS" and "laser". Randomized controlled trials, prospective and retrospective cohorts, case-control studies, and case reports/series with more than five participants were considered eligible for inclusion. Studies reporting the cannula diameter and PPROM rate after laser surgery in the treatment of monochorionic pregnancies affected by TTTS between 16- and 26 weeks' gestation were included. Data was extracted independently, and when appropriate, a random-effects meta-analysis was undertaken to calculate pooled estimates and their confidence intervals. Heterogeneity in the effect estimates of the individual studies was calculated using the I2 statistic. The primary outcome was PPROM rate. Secondary outcomes were survival rate, preterm birth, and incomplete surgery. The quality of the included studies was assessed using a modified quality in prognosis study tool. We included a total of 22 studies, consisting of 3426 patients. Only one study was scored as low quality, seven as moderate quality, and the remaining 14 as high quality. The mean PPROM rate after laser surgery treating TTTS was 22.9%, ranging from 11.6% for 9 French (Fr) to 54.0% for 12 Fr. Subsequent meta-regression for the clinically relevant PPROM rate before 34 weeks of gestation, showed increased PPROM rates for increased cannula size (p-value 0.01). This systematic review confirmed PPROM as a frequent complication of fetal laser surgery, with a mean PPROM rate of 22.9%. A larger cannula diameter relates to a significant higher PPROM risk for PPROM before 34 weeks gestation. Hence, the ideal balance between optimal visualization requiring larger port diameters and shorter operation time and more complete procedures that benefit from larger diameters is crucial to reduce iatrogenic PPROM rates.

Quasi-static compressive properties and damage behavior of aluminum matrix syntactic composites with different diameters of glass cenospheres

Aluminum matrix syntactic composites have broad applications, including aerospace, transportation, military industries, and our daily life owing to lightweight and high energy absorption properties. However, its strength and energy absorption capacity still need improvement. In this study, we prepared an aluminum matrix syntactic composite with smaller diameters glass cenospheres. Due to the higher porosity of the glass cenospheres, the density of the syntactic composites ranged from 1.20–1.27 g cm−3, and the strength and energy absorption could reach up to 172.8 MPa and 75.3 MJ m−3, respectively. Combining finite element and in-situ digital image correlation results, the aluminum matrix syntactic composites with large diameter tend to form 45–90° cracks, resulting in a decrease in material strength with increasing glass cenospheres diameter.

Analysis and experimental research on the reliability of the connection between large-diameter bridge piles and caps

This article investigated the construction conditions of the pile foundation in the Wuxing section of the “Shanghai Suzhou Huzhou” railway bridge project. To test the reliability of large diameter connectors, it has established a finite element model with ABAQUS software for numerical simulation. Based on on-site tests, the reliability of the connection between the pipe pile and the cover steel was studied. According to the simulation results, when the load is P= 900 kN, the displacements of A2 and A3 steel pipe piles are 55.8 mm and 60.1 mm, respectively. The load-displacement relationship shows a high-order curve distribution. According to the results of on-site experiments, the displacements are 77.9 mm and 60.2 mm, respectively. The load-displacement relationship is linear. The results for the simulation and on-site testing are consistent. This study provides a basis to the research on the reliability of the connection between large-diameter steel pipe piles.

Investigation of the effect of different structure parameters and operating factors on the integrated exhaust aftertreatment system for diesel engines and parameter importance analysis

With diesel emission regulations growing more stringent, it is important to study the effect of different structure parameters and operating factors on the integrated aftertreatment system consisting of diesel oxidation catalyst (DOC), catalytic diesel particulate filter (CDPF) and selective catalytic reduction (SCR) during the design and optimization of the aftertreatment system. In this paper, a simulation model capable of exploring the interaction between the aftertreatment components was developed based on some relevant reaction mechanism, and the model accuracy was verified well using the experiment data. Then the effect of different parameters on the overall performance of the aftertreatment system was analyzed qualitatively. Finally, the importance score of each parameter was determined quantitatively based on Latin Hypercubic Sampling method and Random Forests algorithm. The results showed that larger diameter or larger cell density in DOC could improve the aftertreatment performance effectively. The increase in the wall thickness of each component had a negative impact on the aftertreatment system, except for CDPF wall thickness, which improved the filtration efficiency for particular matter (PM). When total aftertreatment length was fixed, high conversion efficiencies for carbon monoxide (CO) and total hydrocarbons (THC) were distributed in the region with large DOC length ratio, and NOx conversion efficiency was affected simultaneously by the length ratio of DOC, CDPF and SCR. An increase in CDPF length ratio and a decrease in DOC and SCR length ratios could contribute to the reduction of total pressure drop. Finally, Random Forests algorithm provided a good identification of the importance score of each parameter. DOC length and diameter played a dominant role in CO and THC conversion. The aftertreatment diameter had higher effect on NOx conversion efficiency than SCR length and PM filtration efficiency was mainly affected by DOC and CDPF length. Based on these qualitative and quantitative results, a design strategy for the integrated aftertreatment system was proposed, which provided some ideas for improving aftertreatment performance.

Redox conditions of Datangpo-type manganese ores constrained by statistical analysis of pyrite framboids and iron isotopes

Datangpo-type manganese ores which originated in the Cryogenian Datangpo Formation, are overlaid and underlaid by Nantuo diamicite and Tiesi'ao silistones, respectively. A thorough understanding of the manganese mineralization process is currently limited by the continued uncertainty regarding the metallogenic redox condition of the Mn-bearing rock series. This study employed statistical analysis of pyrite framboid sizes and iron isotope (δ56Fe) to determine the redox conditions and constrain the mineralization process of Datangpo-type manganese ores in South China, considering the Gaolou in Chongqing, Yanglizhang in Guizhou, and Minle and Zhenxing in Hunan as examples. The results showed that Tiesi'ao siltstones mainly developed relatively larger diameter (7.29–7.68 μm) framboidal pyrites, whereas mudstones in the Datangpo Formation developed relatively smaller diameter (2.63–5.56 μm) framboidal pyrites. Furthermore, manganese ores produce non-framboidal pyrites. In three profiles, framboidal pyrite concentrations were found to be negatively correlated with Mn contents. These characteristics suggested that siltstones, mudstones, and manganese ores were deposited in oxic-anoxic, dysoxic-euxinic, and oxic-dysoxic conditions, respectively. The δ56Fe of whole rocks (δ56FeWR) exhibited a range from −0.73 ‰ to +0.48 ‰ (average of −0.32 ‰), whereas pyrite (δ56FePy) varied from +0.03 ‰ to +0.83 ‰ (average of +0.36 ‰). Furthermore, δ56FePy in manganese ore (average = +0.27 ‰) were lighter than those in mudstone (average = +0.49 ‰). The results of this study demonstrated that oxidation deposition played a role in pyrite formation, with manganese ores exhibiting more oxic conditions compared to mudstones. The findings of this study suggested that idiomorphic pyrite formation was similar to that of manganese ore, in which Mn precipitated in the form of manganese (hydro)oxides under oxic seawater, and then converted into rhodochrosite under anoxic sulfidic diagenetic conditions, with the involvement of microbes. This research has the potential to enhance comprehension regarding redox conditions and the regulation of sedimentary manganese ores via redox transformation.

In Situ-Sprayed Bioinspired Adhesive Conductive Hydrogels for Cavernous Nerve Repair.

Cavernous nerve injury (CNI), resulting in erectile dysfunction (ED), poses a significant threat to the quality of life for men. Strategies utilizing conductive hydrogels have demonstrated promising results for the treatment of peripheral nerves with a large diameter (>2mm). However, integrating convenient minimally invasive operation, antiswelling and immunomodulatory conductive hydrogels for treating small-diameter injured cavernous nerves remains a great challenge. Here, a sprayable adhesive conductive hydrogel (GACM) composed of gelatin, adenine, carbon nanotubes, and mesaconate designed for cavernous nerve repair is developed. Multiple hydrogen bonds provide GACM with excellent adhesive and antiswelling properties, enabling it to establish a conformal electrical bridge with the damaged nerve and aiding in the regeneration process. Additionally, mesaconate-loaded GACM suppresses the release of inflammatory factors by macrophages and promotes the migration and proliferation of Schwann cells. In vivo tests demonstrate that the GACM hydrogel repairs the cavernous nerve and restores erectile function and fertility. Furthermore, the feasibility of sprayable GACM in minimally invasive robotic surgery in beagles is validated. Given the benefits of therapeutic effectiveness and clinical convenience, the research suggests a promising future for sprayable GACM materials as advanced solutions for minimally invasive nerve repair.

Enhanced flow in deformable carbon nanotubes

Many researchers observed enhanced water flow through carbon nanotubes (CNTs) and attributed the reason to large slips. Even after taking significant slip effects into account, there remain unaddressed observations of significant improvements in flow rates. As CNTS are deformable, we represent nanotubes with a deformable-wall using a linear pressure–area relationship. We assume lubrication assumption, and using the properties of nanoconfined water, we derive the model for deformable-nanotubes. We validated our derived model in its limiting cases with the previously reported results in the literature. We compare the predictions by our deformable-wall and rigid-wall model with the experimental results and the MD-simulation predictions by multiple literature studies. Many studies were well-predicted by the rigid-wall model with slips. However, we find that there are many studies with high porosity and thin wall tubes, where elasticity or deformability of the tube is essential in modeling, which is well-predicted by our deformable-wall model with slips. In our study, we focus on investigating the impact of two key factors: the deformability, and the slip length on the flow rate. We find that the flow rate inside the tube increases as the deformability increases or the thickness T and elastic modulus E of the tube-wall decrease). We also find that the flow rate in deformable tubes scales as m˙deformable∼1/α0 for (Δp/αAo)≪1, m˙deformable∼1/α for (Δp/αAo)∼O(10−1) and m˙deformable∼α2 for (Δp/αAo)∼O(1). Further, for a given deformability, the percentage change in flow rate in the smaller diameter of the tube is much larger than the larger diameter. As the tube diameter decreases for the given pressure, Δm˙/m˙ increases. We find that for rigid-tube, the flow rate varies m˙rigid∼Δp, whereas for the deformable-tubes, the flow rate scales as m˙deformable∼Δp2 for (Δp/αAo)∼O(10−1), and finally to m˙deformable∼Δp3 for (Δp/αAo)∼O(1). We further find that slip also significantly increases flow rate, but, deformability has more substantial effect.

The prognostic role of single cell invasion and nuclear diameter in early oral tongue squamous cell carcinoma

BackgroundThe clinical significance of single cell invasion and large nuclear diameter is not well documented in early-stage oral tongue squamous cell carcinoma (OTSCC).MethodsWe used hematoxylin and eosin-stained sections to evaluate the presence of single cell invasion and large nuclei in a multicenter cohort of 311 cases treated for early-stage OTSCC.ResultsSingle cell invasion was associated in multivariable analysis with poor disease-specific survival (DSS) with a hazard ratio (HR) of 2.089 (95% CI 1.224–3.566, P = 0.007), as well as with disease-free survival (DFS) with a HR of 1.666 (95% CI 1.080–2.571, P = 0.021). Furthermore, large nuclei were associated with worse DSS (HR 2.070, 95% CI 1.216–3.523, P = 0.007) and with DFS in multivariable analysis (HR 1.645, 95% CI 1.067–2.538, P = 0.024).ConclusionSingle cell invasion and large nuclei can be utilized for classifying early OTSCC into risk groups.

Optimizing the temporal and spatial resolutions and light throughput of Fresnel incoherent correlation holography in the framework of coded aperture imaging

Fresnel incoherent correlation holography (FINCH) is a well-established digital holography technique for 3D imaging of objects illuminated by spatially incoherent light. FINCH has a higher lateral resolution of 1.5 times that of direct imaging systems with the same numerical aperture. However, the other imaging characteristics of FINCH, such as axial resolution, temporal resolution, light throughput, and signal-to-noise ratio (SNR), are lower than those of direct imaging systems. Different techniques were developed by researchers around the world to improve the imaging characteristics of FINCH while retaining the inherent higher lateral resolution of FINCH. However, most of the solutions developed to improve FINCH presented additional challenges. In this study, we optimized FINCH in the framework of coded aperture imaging. Two recently developed computational methods, such as transport of amplitude into phase based on the Gerchberg Saxton algorithm and Lucy–Richardson–Rosen algorithm, were applied to improve light throughput and image reconstruction, respectively. The above implementation improved the axial resolution, temporal resolution, and SNR of FINCH and moved them closer to those of direct imaging while retaining the high lateral resolution. A point spread function (PSF) engineering technique has been implemented to prevent the low lateral resolution problem associated with the PSF recorded using pinholes with a large diameter. We believe that the above developments are beyond the state-of-the-art of existing FINCH-scopes.

Recycled Polystyrene Waste to Triboelectric Nanogenerators: Volumetric Electromechanically Responsive Laminates from Same‐Material Contact Electrification

Millions of tonnes of polystyrene (PS) are produced annually, with only an estimated 12% being recycled. Herein, the upcycling of expanded or foamed PS waste into electromechanically responsive triboelectric laminates (TLs) is described. These TLs possess internal triboelectric dipoles offering an alternative to ferroelectric fluoropolymers, and, when manufactured into triboelectric nanogenerators (TENGs), are able to generate over 200 V and 12 μA from motion. This energy harvesting is enabled by electrospinning alternating layers of small and large diameter PS fibers, which upon friction establish an effective dipole moment within the TL. The PS‐TENG shows remarkable stability and is able to charge a 0.47 μF capacitor to 15 V in 200 s of vibration from same material contact electrification, with piezoelectric contact‐mode testing showing that a single PS laminate is comparable to state‐of‐the‐art piezoelectric fluoropolymers for overall electromechanical conversion.

Slope Stability Analysis of Mounded Storage Tank under Different Compaction Coefficients

Mounded storage tank is to cover the storage tank with compacted soil on the ground to avoid steam cloud explosion, ensuring the stability and safety of the storage tank. In view of the influence of large diameter and surface radian of the tank, slope stability of mounded storage tank under different compaction coefficients has become the focus of research. In this paper, a series of laboratory tests were carried out to obtain the physical and mechanical parameters of the soil samples collected from the overburden of one specific engineering project. On this basis, Plaxis2D finite element software was used to establish a numerical model of the horizontal tank with a diameter of 7.6 m and a length of 76 m and the mounded slope with a height of 16.25 m as the research object. The effects of different compaction coefficients, slope angles, and overburden thicknesses on the slope stability of the mounded storage tank are investigated. Results indicate that the slope stability coefficients increase with the increase of compaction coefficient but decrease with the increase of slope angle and overburden thickness. Under the condition of the compaction coefficient 0.75–0.95, slope angle 30°–60°, and overburden thickness 0.5–1.3 m, the sensitivity ranking on the slope stability of mounded storage tank is: compaction coefficient, slope angle, and overburden thickness. The analysis results can provide an important theoretical basis and technical support for the safety and stability evaluation of mounded horizontal tank project.

Application of the strip clear-cutting system in a running bamboo (Phyllostachys glauca McClure) forest: feasibility and sustainability assessments.

As a renewable forest resource, bamboo plays a role in sustainable forest development. However, traditional cutting systems, selection cutting (SeC) and clear-cutting (ClC), result in an unsustainable production of bamboo forests due to labor-consuming or bamboo degradation. Recently, a strip clear-cutting (StC) was theoretically proposed to promote the sustainability of bamboo production, while little is known about its application consequence. Based on a 6-year experiment, we applied the strip clear-cutting system in a typical running bamboo (Phyllostachys glauca McClure) forest to assess its feasibility and sustainability. Using SeC and ClC as controls, we set three treatments with different strip widths (5 m, 10 m, and 20 m) for strip clear-cutting, simplified as StC-5, StC-10, and StC-20, respectively. Then, we investigated leaf physiological traits, bamboo size and productivity, population features, and economic benefits for all treatments. The stands managed by StC had high eco-physiological activities, such as net photosynthetic rate (P n), photosynthetic nitrogen use efficiency (PNUE), and photosynthetic phosphorus use efficiency (PPUE), and thus grew well, achieved a large diameter at breast height (DBH), and were tall. The stand biomass of StC (8.78 t hm-2 year-1) was 1.19-fold and 1.49-fold greater than that of SeC and ClC, respectively, and StC-10 and StC-20 were significantly higher than SeC or ClC (p< 0.05). The income and profit increased with the increase in stand density and biomass, and StC-20 and StC-10 were significantly higher than SeC or ClC (p< 0.05). Using principal components analysis and subordinate function analysis, we constructed a composite index to indicate the sustainability of bamboo forests. For the sustainability assessment, StC-10 had the highest productive sustainability (0.59 ± 0.06) and the second highest economic sustainability (0.59 ± 0.11) in all cutting treatments. StC-10 had the maximum overall sustainability, with a value of 0.53 ± 0.02, which was significantly higher than that of ClC (p< 0.05). The results verified that StC for Phyllostachys glauca forests is feasible and sustainable as its sustainability index outweighs those of traditional cutting systems (SeC and ClC), and 10 m is the optimum distance for the strip width of StC. Our findings provide a new cutting system for managing other running bamboo forests sustainably.

Making the case for resistance training in improving vascular function and skeletal muscle capillarization.

Through decades of empirical data, it has become evident that resistance training (RT) can improve strength/power and skeletal muscle hypertrophy. Yet, until recently, vascular outcomes have historically been underemphasized in RT studies, which is underscored by several exercise-related reviews supporting the benefits of endurance training on vascular measures. Several lines of evidence suggest large artery diameter and blood flow velocity increase after a single bout of resistance exercise, and these events are mediated by vasoactive substances released from endothelial cells and myofibers (e.g., nitric oxide). Weeks to months of RT can also improve basal limb blood flow and arterial diameter while lowering blood pressure. Although several older investigations suggested RT reduces skeletal muscle capillary density, this is likely due to most of these studies being cross-sectional in nature. Critically, newer evidence from longitudinal studies contradicts these findings, and a growing body of mechanistic rodent and human data suggest skeletal muscle capillarity is related to mechanical overload-induced skeletal muscle hypertrophy. In this review, we will discuss methods used by our laboratories and others to assess large artery size/function and skeletal muscle capillary characteristics. Next, we will discuss data by our groups and others examining large artery and capillary responses to a single bout of resistance exercise and chronic RT paradigms. Finally, we will discuss RT-induced mechanisms associated with acute and chronic vascular outcomes.

Influence of en-APTAS membrane on NO gas selectivity of HfO2-based memristor gas sensors

Memristor-based gas sensors (gas sensor + memristor, gasistor) have gained popularity due to their high response characteristics and ability to operate at RT. In this paper, N-[3-(Trimethoxysilyl)propyl]ethylenediamine (en-APTAS), a commonly used membrane for NO x gas sensors, is applied in the gasistor with carbon nanotubes (CNTs)-top electrode (TE). As a result, we have demonstrated the response time was reduced by 104 s, and the response to 10 ppm Nitric oxide (NO) gas increased to 3.69, indicating an enhanced sensing property in a range of 10–50 ppm. Furthermore, when decorated with the proposed en-APTAS, the gasistor with CNTs-TE demonstrated a 3.76-fold increase in response to NO gas compared to NO2 gas, demonstrating remarkable selectivity. These improved features are attributed to the high adsorption energy of en-APTAS and the large kinetic diameter of NO2. The research proposal will be a foundational stage towards attaining selectivity in other gasistor studies.

Insights Into Frictional Brush Seal Hysteresis

Abstract Brush seals offer a superior sealing effectiveness compared to labyrinth seals. However, widespread use of brush seals is constrained by deleterious behaviors such as pressure-stiffening and hysteresis. For the latter, the bristles bend during the shaft incursion process and do not fully recover during the shaft retraction process. An opening gap is created, which increases seal leakage unless the pressure load drops to a certain level. In this work, analytical and numerical models based on a single bristle are proposed to capture the seal's response to shaft displacement with and without pressure loading. The models are validated using static stiffness tests at an unpressurized condition from literature. The main results show that modeling of the backing ring friction is essential to capture the bristle hang-up behavior. Shaft friction dominates at unpressurized conditions, while backing ring friction dominates at high pressure loading. An expression for shaft hang-up displacement has been derived. A sensitivity study shows that seals with shallow lay angle, short bristle length, and large bristle diameter are less prone to hang-up problems. The models developed in the present framework have been shown to qualitatively capture the pressure stiffening, hysteresis, bristle hang-up, and shaft rotation effects.