Small Opening Research Articles

The flow model of the overlap spool valve considering the transition between laminar and turbulent flow

It remains uncertain whether the flow state at the spool valve is laminar or turbulent under small openings. The annular slit flow and the damping hole flow are proposed to be equated to model the spool valve flow. The mutual transition criterion between laminar and turbulent flows is developed. The results indicate that the flow turns from transitional flow to turbulence as the valve opening increases to 5.2 μm. The flow coefficient increases linearly in transitional flow and remains constant in turbulence. Laminar flow may occur when the annular gap's length exceeds 9.45 μm. The effect of structural parameters including overlap, radial clearance, wear fillet, and temperature on flow transition is discussed. Wear on the valve port counteracts the positive overlap. Flow gain continues to rise, pressure gain increases and then falls, reaching a maximum of 5 × 1012 Pa/m. Valve performance exhibits a brief ramp-up time. The theoretical model and analysis aim to elucidate the flow characteristics and performance evolution of the spool valve.

The Source of Nasal Rustle (Nasal Turbulence): An Overview of Current Evidence.

Nasal rustle (also called nasal turbulence) refers to a loud distracting sound that sometimes occurs with audible nasal emission (ANE) during the production of pressure-sensitive consonants in patients with velopharyngeal insufficiency (VPI). This article examines evidence for two hypotheses of causality: vibration of the soft palate (velar flutter) and periodic motion of mucus above the velopharyngeal port (turbulent mucus). A review of the relevant literature shows inconclusive evidence to support velar flutter as a cause of nasal rustle. In contrast, clinical observations and research involving high-speed nasopharyngoscopy suggest that nasal rustle is the result of turbulent mucus above a small velopharyngeal opening. Therefore, it is our contention that a plausible explanation for nasal rustle is one of turbulent mucus and not velar flutter.

Effects of Spatial Type and Scale of Small Urban Open Spaces on Perceived Restoration: An Online Survey-Based Experiment

Small urban open spaces are critical components of high-density urban environments, and could bring multiple health benefits. However, the factors related to the restorative effect of these small urban open spaces are not well studied. This study explored how site type (lawn, water, and plaza) and spatial scales (10 × 10 m, 20 × 20 m, 30 × 30 m, and 40 × 40 m) might be associated with small urban open space’s restorative effects. We created the virtual scene images of the 12 sites and used PRS-11 to measure 1130 participants’ perceived restoration when viewing those images. The results indicated that lawn has the highest restorative effects, and are the most preferred. No significant differences in the restorative effects of sites with different spatial scales were detected, even a 10 × 10 m site has considerable restorative effects. We found high preference contributes to larger differences in the restorative effects of lawns and plazas. Those who prefer the sites may gain more restoration increases when viewing lawn scenes compared to plaza scenes. Moreover, adults over 50 years old have higher perceived restorations, and young adults aged 18–25 have a greater increase in restoration between plaza scenes and natural scenes, indicating young adults could benefit more from the building of small green spaces. These findings have direct implications for design practice. More small urban open spaces of lawn and water should be built to provide more restoration benefits, especially for young people.

Editorial for the Special Issue of Comparative Economic Studies: 50 Years After the End of Bretton Woods—The Experiences of Small Open Economies

AbstractThis special issue of Comparative Economic Studies, commemorating fifty years since the end of the Bretton Woods system, examines the adjustment of small open economies to floating exchange rates and new monetary policy frameworks. Based on a workshop held at the KOF Swiss Economic Institute in June 2023, six papers analyse dimensions such as the evolution of monetary policy regimes, the impact of economic crises and the use of unconventional monetary policies in Canada, Israel, Norway, Sweden and Switzerland. The findings highlight the benefits and limitations of inflation targeting, the challenges of global financial integration and the strategic responses of central banks to maintain stability and independence, providing policymakers with valuable insights into the complex dynamics of monetary policy in the post-Bretton Woods era.

Large-deformation finite-element modelling of face instability during tunnelling in clayey soils: Incorporating dynamic excavation process

Earth pressure balance (EPB) shield tunnelling plays a crucial role in urban infrastructure development but faces challenges due to potential face instability. Previous studies often overlook the impact of dynamic excavation processes on face stability, particularly in clayey soils. This study proposes a three-dimensional coupled Eulerian-Lagrangian (CEL) large-deformation approach to explore the failure process of tunnel face in clayey soils during both EPB shutdown and excavation conditions by incorporating the influence of dynamic excavation process. The findings reveal that the face stability during dynamic excavation conditions is consistently lower than that during EPB shutdown, indicating that neglecting dynamic excavation effects could overestimate face stability, potentially compromising construction safety. Moreover, when considering the dynamic excavation process, the opening ratio ξ (the ratio between the cross-section area of cutterhead opening to the total area of tunnel face) is a critical factor affecting face stability. As expected, the face is more stable for a small opening ratio (e.g., ξ = 15 %) while face stability is reduced for a large opening ratio (e.g., ξ = 30 % and 50 %). This is because for large opening ratio, the soil disturbance caused by the cutterhead excavation process exceeds the supportive effect that the cutterhead panels can provide to the face. Finally, the obtained numerical results were used to calculate support pressure in a real tunnel project considering the dynamic excavation process, which matches well with the measured data in the project, validating the effectiveness and superiority of the current CEL approach in modelling face instability and estimating face support pressure. This study offers a significant advancement over the traditional methods for the design of support pressure in clayey soils, providing new insight into the dynamic cutterhead-soil interaction and valuable guidance for reducing the risk of face collapse.

How Much Price Stickiness in Hong Kong? —Evidence from Small Open Economy DSGE and Indirect Inference

How Much Price Stickiness in Hong Kong? —Evidence from Small Open Economy DSGE and Indirect Inference

Seepage monitoring and leaks detection along an earth dam with a multi-sensor thermal-active system

Thermal investigation using linear sensors installed in the ground is currently one of the most effective methods for analyzing seepage processes in the bodies of earth dams or dikes and their subsoil, including leaks detection. However, linear, fiber-optic temperature sensors present several limitations when applied to existing structures, including installation difficulties and substantial costs. To enhance the applicability of the thermal method for studying subsurface water flow, a novel Multi-Point Thermal-Active Monitoring method has been devised. The approach consists of installing, through hammering, thermal-active sensors side-by-side in the ground, at the same depth in a single line thereby achieving quasi-continuous measurements along the structure. Small openings from sensor installation are secured with bentonite and do not pose a threat to the structure. Each sensor is equipped with a micro-heater, which enables the use of the thermo-active method to determine in-situ seepage velocity. This article describes this method and its initial application in 2014 on one of the Polish earth dams. This application enabled the detection of two leakage zones and the monitoring of their flow velocities, leading to the successful validation of the described technology.

A small opening in the storm clouds: overview of the registry-based study on the management of thyroid storm.

Due to the high mortality rate of TS, effective guidance for its diagnosis and treatment is essential. The diagnostic criteria introduced by the JTA in 2012, along with the Burch-Wartofsky Point Scale, constitute valuable tools for the diagnosis of TS. In 2016, Guidelines on the management of TS were produced by the JTA and the JES. Recently, a prospective multicenter register-based study compared the prognosis and outcome of 110 new-onset TS patients with the results of previous comparable studies and evaluated the efficacy of the Guidelines. The study revealed higher APACHE II scores and significant correlations between lower BMI, post-resuscitation shock, and fever with outcomes and, overall, improved TS prognosis. Most patients in the study received methimazole and potassium iodide, the timely administration of which was linked to lower fatality rates. Adherence to treatment guidelines correlates with lower mortality rates, emphasizing the importance of experienced multidisciplinary teams in ICU settings and the necessity for periodic review of the guidelines to enhance therapeutic approaches and reduce mortality.

Rp3: Ribosome profiling-assisted proteogenomics improves coverage and confidence during microprotein discovery

There has been a dramatic increase in the identification of non-canonical translation and a significant expansion of the protein-coding genome. Among the strategies used to identify unannotated small Open Reading Frames (smORFs) that encode microproteins, Ribosome profiling (Ribo-Seq) is the gold standard for the annotation of novel coding sequences by reporting on smORF translation. In Ribo-Seq, ribosome-protected footprints (RPFs) that map to multiple genomic sites are removed since they cannot be unambiguously assigned to a specific genomic location. Furthermore, RPFs necessarily result in short (25-34 nucleotides) reads, increasing the chance of multi-mapping alignments, such that smORFs residing in these regions cannot be identified by Ribo-Seq. Moreover, it has been challenging to identify protein evidence for Ribo-Seq. To solve this, we developed Rp3, a pipeline that integrates proteogenomics and Ribosome profiling to provide unambiguous evidence for a subset of microproteins missed by current Ribo-Seq pipelines. Here, we show that Rp3 maximizes proteomics detection and confidence of microprotein-encoding smORFs.

Femora nutrient foramina and aerobic capacity in giant extinct xenarthrans.

Nutrient foramina are small openings in the periosteal surface of the mid-shaft region of long bones that traverse the cortical layer and reach the medullary cavity. They are important for the delivery of nutrients and oxygen to bone tissue and are crucial for the repair and remodeling of bones over time. The nutrient foramina in the femur's diaphysis are related to the energetic needs of the femur and have been shown to be related to the maximum metabolic rate (MMR) of taxa. Here, we investigate the relationship between nutrient foramen size and body mass as a proxy to the aerobic capacity of taxa in living and extinct xenarthrans, including living sloths, anteaters, and armadillos, as well as extinct xenarthrans such as glyptodonts, pampatheres, and ground sloths. Seventy femora were sampled, including 20 from extant taxa and 50 from extinct taxa. We obtained the blood flow rate (Q̇) based on foramina area and performed PGLS and phylogenetic ANCOVA in order to explore differences among mammalian groups. Our results show that, among mammals, taxa commonly associated with lower metabolism like living xenarthrans showed relatively smaller foramina, while the foramina of giant extinct xenarthrans like ground sloths and glyptodonts overlapped with non-xenarthran placentals. Consequently, Q̇ estimations indicated aerobic capacities comparable to other placental giant taxa like elephants or some ungulates. Furthermore, the estimation of the MMR for fossil giant taxa showed similar results, with almost all taxa showing high values except for those for which strong semi-arboreal or fossorial habits have been proposed. Moreover, the results are compatible with the diets predicted for extinct taxa, which indicate a strong consumption of grass similar to ungulates and in contrast to the folivorous or insectivorous diets of extant xenarthrans. The ancestral reconstruction of the MMR values indicated a lack of a common pattern for all xenarthrans, strongly supporting the occurrence of low metabolic rates in extant forms due to their particular dietary preferences and arboreal or fossorial habits. Our results highlight the importance of considering different evidence beyond the phylogenetic position of extinct taxa, especially when extinct forms are exceptionally different from their extant relatives. Future studies evaluating the energetic needs of giant extinct xenarthrans should not assume lower metabolic rates for these extinct animals based solely on their phylogenetic position and the observations on their extant relatives.

Effects of current intensities on material removal rate, electrode wear rate, and surface roughness of machining high carbon high chromium steel

AbstractThe electrical discharge machining is very successful and generally recognized for producing complicated shapes and small openings with exceptional precision. The objective of this study is to assess the impact of different electrical discharge machining parameters on the attributes of the machining process. The evaluation of the machining process was conducted based on the workpiece‘s material removal rate, the rate at which the electrodes wear, and the level of surface roughness. Simultaneously achieving a high material removal rate, low electrode wear rate, and high surface roughness is not possible with a specific combination of approaches due to their contradicting nature. Frequently, it is necessary to independently apply many measures instantaneously in order to assess their impact on various responses. This research investigates the machining of high carbon high chromium steel making use of electrical discharge machining with aluminum, copper, and graphite electrodes. The study focuses on the impact of different current intensities on the rate of material removal, electrode wear, and surface roughness. The experimental results demonstrate that the highest material removal rate (mmcubicmin−1) is achieved at a current density of 12 A when using a copper electrode (54.67), as opposed to aluminum electrode (22.91) and graphite electrode (29.43).

The effects of brick wall and RC tie variables on the seismic performance of low-rise confined masonry buildings

An extensive parametric investigation is carried out to determine the effects of different RC tie system and brick wall variables on the performance of confined masonry walls and buildings. The variables considered include: the number of storeys and adjacent walls, the walls aspect ratio, thickness and compressive strength of masonry walls, presence of openings, the RC tie system dimensions, compressive strength and detailing of the longitudinal and transverse reinforcements. The main aim of the investigation is to verify the efficiency of some of the prescriptive code recommendations and to provide a basis for further descriptive guidelines for low-rise confined masonry buildings. Among the major conclusions, it is found that the main affecting parameters are those of the masonry walls themselves. When the walls have sufficient shear capacities, due to lower aspect ratio, higher compressive strength and wall thickness and lack of, or small openings, the flexural demand on the tie system is small and its elements act mainly as axially-loaded tie elements. Therefore, the least affecting parameters are those of the tie system's reinforcement detailing. However, when the masonry walls are weak in shear (low masonry strength and large openings), the demand on the tie system increases, to the point that instead of acting as an integral part of the wall, it acts similar to a weak, moment-resisting frame having infill masonry walls, for which it has not been designed. The scenarios that this will happen include: the wall aspect ratios AR > 2, the masonry compressive strength, f′m < 5.0 MPa and the ratio of length of opening to the length of the wall, Ol/Wl > 0.5. To avoid such behaviour, it is also suggested that the tensile stresses in the longitudinal bars of the RC tie elements be limited to 0.6fy.

D-sORF: Accurate Ab Initio Classification of Experimentally Detected Small Open Reading Frames (sORFs) Associated with Translational Machinery.

Small open reading frames (sORFs; <300 nucleotides or <100 amino acids) are widespread across all genomes, and an increasing variety of them appear to be translating from non-genic regions. Over the past few decades, peptides produced from sORFs have been identified as functional in various organisms, from bacteria to humans. Despite recent advances in next-generation sequencing and proteomics, accurate annotation and classification of sORFs remain a rate-limiting step toward reliable and high-throughput detection of small proteins from non-genic regions. Additionally, the cost of computational methods utilizing machine learning is lower than that of biological experiments, and they can be employed to detect sORFs, laying the groundwork for biological experiments. We present D-sORF, a machine-learning framework that integrates the statistical nucleotide context and motif information around the start codon to predict coding sORFs. D-sORF scores directly for coding identity and requires only the underlying genomic sequence, without incorporating parameters such as the conservation, which, in the case of sORFs, may increase the dispersion of scores within the significantly less conserved non-genic regions. D-sORF achieves 94.74% precision and 92.37% accuracy for small ORFs (using the 99 nt medium length window). When D-sORF is applied to sORFs associated with ribosomes, the identification of transcripts producing peptides (annotated by the Ensembl IDs) is similar to or superior to experimental methodologies based on ribosome-sequencing (Ribo-Seq) profiling. In parallel, the recognition of putative negative data, such as the intron-containing transcripts that associate with ribosomes, remains remarkably low, indicating that D-sORF could be efficiently applied to filter out false-positive sORFs from Ribo-Seq data because of the non-productive ribosomal binding or noise inherent in these protocols.

A Study on Three-Dimensional Multi-Cluster Fracturing Simulation under the Influence of Natural Fractures

Multi-cluster fracturing has emerged as an effective technique for enhancing the productivity of deep shale reservoirs. The presence of natural bedding planes in these reservoirs plays a significant role in shaping the evolution and development of multi-cluster hydraulic fractures. Therefore, conducting detailed research on the propagation mechanisms of multi-cluster hydraulic fractures in deep shale formations is crucial for optimizing reservoir transformation efficiency and achieving effective development outcomes. This study employs the finite discrete element method (FDEM) to construct a comprehensive three-dimensional simulation model of multi-cluster fracturing, considering the number of natural fractures present and the geo-mechanical characteristics of a target block. The propagation of hydraulic fractures is investigated in response to the number of natural fractures and the design of the multi-cluster fracturing operations. The simulation results show that, consistent with previous research on fracturing in shale oil and gas reservoirs, an increase in the number of fracturing clusters and natural fractures leads to a larger total area covered by artificial fractures and the development of more intricate fracture patterns. Furthermore, the present study highlights that an escalation in the number of fracturing clusters results in a notable reduction in the balanced expansion of the double wings of the main fracture within the reservoir. Instead, the effects of natural fractures, geo-stress, and other factors contribute to enhanced phenomena such as single-wing expansion, bifurcation, and the bending of different main fractures, facilitating the creation of complex artificial fracture networks. It is important to note that the presence of natural fractures can also significantly alter the failure mode of artificial fractures, potentially resulting in the formation of small opening shear fractures that necessitate careful evaluation of the overall renovation impact. Moreover, this study demonstrates that even in comparison to single-cluster fracturing, the presence of 40 natural main fractures in the region can lead to the development of multiple branching main fractures. This finding underscores the importance of considering natural fractures in deep reservoir fracturing operations. In conclusion, the findings of this study offer valuable insights for optimizing deep reservoir fracturing processes in scenarios where natural fractures play a vital role in shaping fracture development.

A SWOT Analysis of Small Private Online Courses

While some research has been conducted to identify the strengths and weaknesses of Small Private Open Courses (SPOCs), a significant research gap exists in comprehensively examining the opportunities and threats they face. To determine if SPOCs are beneficial to learners, the authors adopted the PRISMA protocol to filter literature for SWOT analysis in SPOCs. The authors identified and analyzed the strengths, weaknesses, opportunities and threats faced by SPOCs using a SWOT analysis method. The strengths of SPOCs include high-quality content and course delivery, accessibility, and personalization. Weaknesses involve lack of social interaction, limited resources, credentialing issues. Their opportunities consist of market growth, collaboration with other institutions, and access to new student markets. Their threats include competition from traditional courses, technology updates, and student privacy concerns.

Rationale and tips and tricks for transgastric robotic pancreaticogastrostomy by the double purse-string technique.

Pancreaticogastrostomy (PG) is a viable option for selected patients needing a pancreatic anastomosis. The double purse-string technique can facilitate the construction of transgastric PG but in a minimally invasive approach can lead to complications due to lack of tactile feedback. We present an adaptation of double purse-string PG for the robotic surgery, with several modifications. Firstly, the inner purse-string suture is tied through the anterior gastrotomy to improve the approximation of gastric and pancreatic serosae. Secondly, all-around-the-clock intragastric interrupted mattress sutures of e-PTFE are used to secure the pancreatic remnant to the stomach, enhancing improve hemostasis. Thirdly, e-PTFE sutures precise tension calibration due to their elastic properties and resistance to robotic manipulation. Fourthly, retroperitoneal vessels are preemptively covered by passing the pancreatic remnant through a small opening in the omentum, which is rotated upward in the omental bursa. This technique was employed in 20 PGs with no grade C postoperative pancreatic fistula. It offers a viable option robotic pancreatic anastomosis.

Performance of Reinforced Concrete Beams with Rectangular Opening in Flexural and Shear Zone

Transverse openings in reinforced concrete beams use to house the utility services like electricity cable, Internet cable, air-conditioning pipe, fire safety pipe line and water-drainage system. These beams opening pipe line system are usually placed underneath the soffit of the beam in term of dead space. This height of dead space that increase the overall building height. Beam opening in the reinforced concrete beams significantly decreases the ultimate load carrying capacity of beam. Transverse beam opening in the web portion of beam produces discontinuities in the usual flow of stresses and that leading stress concentration around the opening region. The importance of this study is to evaluate the performance of reinforced concrete beam with varying size rectangular opening at flexure and shear location ware investigated. A nonlinear finite element analysis was conducted to investigate the effects of different size openings, in terms of ultimate load carrying capacity, Elemental Stresses, load-deflection plot, crack pattern. The work involves investigating performance of different size of small and large rectangular opening. This paper gives new challenges for engineering practice which is in the field of strengthening of concrete structures especially in transverse RC beams with rectangular openings.

Clonal response of a recalcitrant understory shrub, Labrador tea (Rhododendron groenlandicum Oeder.) to forest gaps

After canopy removing disturbance, recalcitrant understory shrubs can rapidly occupy the forest understory to the detriment of tree regeneration and growth. The expansion of recalcitrant species has been documented following stand replacing disturbances, such as fire and timber harvest. However, there is little information on how these species respond to much smaller canopy gaps created by the senescence and (or) death of single or groups of canopy trees. In this study, we determined the response of Labrador tea ( Rhododendron groenlandicum Oeder.), a recalcitrant ericaceous shrub, to canopy gaps in a late-successional boreal forest in northwestern Ontario, Canada. We evaluated functional traits related to the morphology and regeneration strategy of this plant to elucidate the mechanism of gap filling. We found that R. groenlandicum abundance and vigor were greater at the center of treefall gaps than in gap edges or the forest understory due to aggressive sprouting from buried clonal bud banks. Layering was higher in canopy gaps than in the understory. The composition of ground cover and rooting substrate was more influential on the adventitious rooting of the layered stems than increased light availability in gaps. We found a strong response of R. groenlandicum to small canopy openings, suggesting that the species can form recalcitrant understory layers even in the absence of stand replacing disturbance.

Fire behavior of high‐contents recycled aggregate concrete composite slabs with small openings

AbstractRecycled aggregate concrete (RAC) is increasingly being used in the construction of structural elements. However, the performance of RAC elements under fire is usually considered to be inferior to that of normal concrete (NC) elements. This study investigates the fire behavior of RAC composite steel slabs with and without openings. Ten slabs of size of 1.0 m × 2.2 m were cast either with no opening, one or two circular openings, and one or two square openings. Five of the slabs were manufactured with 100% RAC, while the other five slabs were made with NC. The concrete slabs were loaded and subjected to fire tests at a temperature of about 900°C for 120 min. Test results show that RAC composite slabs have lower stiffness (thus larger mid‐span deflections) under fire exposure compared to their counterpart NC slabs. In terms of the recorded temperature–time curves, RAC slabs showed similar performance to that of NC slabs. The ratio of soffit temperature to the temperature at the top of slab was considerably smaller for RAC slabs compared to NC slabs. RAC slabs also showed more spalling than NC slabs. Experimental test results were numerically verified using PyroSim® software with the two showing good agreement. A series of new design charts for composite RAC slabs with desired fire endurance are proposed. This study is expected to promote the wider use of RAC in construction of structural elements, particularly of composite slabs exposed to extreme temperatures.

Analysis of Pressure Fluctuation of a Pump-Turbine with Splitter Blades on Small Opening in Turbine Mode

Unstable flow in a pump-turbine can cause pressure pulsation, and the resulting vibration deteriorates the stability and operating safety of the unit. This study conducted three-dimensional numerical calculations of the overall flow passage of a pump-turbine with splitter blades under the small guide vane opening, and the unsteady flow characteristics of the turbine were investigated. The results showed that the pressure fluctuation was more severe at lower head operating conditions with lower efficiency, especially in the vaneless area (the runner blade passages). Under the lower head condition, the proportion of 12 times the rotational frequency (12 f/fn) increased in the vaneless area, and the amplitude of 1 f/fn as well as 2 f/fn became larger in the runner blade channel, with more space occupied by vortices and reflux areas. A spiral vortex rope formed in the draft tube, increasing the proportion of 0.4 f/fn and 0.7 f/fn pressure pulses.