Small Channels Research Articles

On the river flow motion in the bend channel cross-section

At the river bed curves, secondary flow normal to the main flow direction are formed. Depending on the channel geometry, there may be several secondary flows in the cross-section, and they may have different scales. Even a small secondary cross-section flow affects the parameters of the hydrodynamic flow and this influence must be taken into account when modeling riverbed processes and researching coast deformations of the channel. Three-dimensional modeling of such multi-scale processes requires large computational costs and is currently possible only for small model channels. Therefore, a reduced-dimensional model is proposed in this paper to study coastal processes. The performed reduction of the problem from a three-dimensional model of river flow motion to a two-dimensional one in the plane of the channel cross-section assumes that the hydrodynamic flow is quasi-stationary and the hypotheses on the asymptotic behavior of the flow along the flow coordinate are fulfilled for it. Taking into account these limitations, a mathematical model of the problem of a stationary turbulent calm river flow in a channel cross-section is formulated in this work. The problem is formulated in a mixed velocity–vortex–stream function formulation. Specifying of the boundary conditions on the flow free surface for the velocity field determined in the normal and tangential directions to the cross-section axis is required as additional conditions for the problem reduction. It is assumed that the values of this velocity field should be determined from the solution of auxiliary problems or obtained from data of natural or experimental measurements. The finite element method in the Petrov–Galerkin formulation is used for the numerical solution of the formulated problem. A discrete analog of the problem is obtained and an algorithm for its solution is proposed. The performed numerical studies showed generally good agreement between the obtained solutions and the known experimental data. The authors associate the errors in the numerical results with the need for a more accurate determination of the radial component of the velocity field in the cross-section by selecting and calibrating a more suitable model for turbulent viscosity calculating and a more accurate determination of the boundary conditions on the cross-section free boundary.

A Study on the Flow Measurement Performance of the Plate Flowmeter and Its Effect on Channel Flow Velocity Distribution

The plate flowmeter offers a novel method for water flow measurement in small channels. Characterized by its simple construction, absence of siltation, and consistent relationship between the deflection angle and flow rate, this device possesses significant potential. Our study, employing rigorous experimental techniques, validated that the gate-hole outflow calculation model is effectively applicable to this plate flowmeter. Additionally, our research investigated the device’s impact on flow velocity distribution. Our findings reveal that the plate flowmeter can be effectively combined with the sluice gate outflow model. It has been verified that the maximum relative error is 14.57%, the minimum relative error is 0.35%, and most relative errors are below 10%. Both water level and flow rate contribute to the flat plate device’s relative head loss, with water level exerting a more significant effect. At various points along the channel, the plate flowmeter affects flow velocity distribution differently. Upstream, the device minimally impacts vertical flow velocity distribution, resulting in steady velocity changes. Conversely, downstream, the flat plate flow meter significantly alters flow velocity distribution, prompting redistribution that persists until 1.26 m downstream, where device influence ceases. These insights offer a solid theoretical foundation for enhancing the structural design of the plate flowmeter, thus improving its overall performance and efficacy.

Theory of Gas Purification by Liquid Absorber in Small Rotating Channels with Application to the Patented Rotational Absorber Device

A new design for absorbing vapour-phase impurities from gases is presented. It consists of small channels packed in a rotating vertical cylinder. Gas flows through the channels adjacent to a thin film of absorber liquid. The liquid film is pressed to the radially outward side of each channel by the centrifugal force and flows downwards by gravity. Formulae are presented which describe the concentration distributions of gaseous impurities subject to absorption in gas and liquid. Results include expressions for laminar and turbulent diffusion coefficients to be used in mass balance equations. The role of rotation is quantified including the effect on wavy motion and enhanced diffusion in the liquid layer. Application in design is indicated for the case of separation of the greenhouse gas CO2 from flue gases of fossil fuel combustion processes. At other equal dimensions, the height of the Rotational Absorber Device is calculated to be 25 times shorter than the enormous heights of conventional tray and packed columns.

Nitric Oxide and Small and Intermediate Calcium-Activated Potassium Channels Mediate the Vasodilation Induced by Apigenin in the Resistance Vessels of Hypertensive Rats.

Apigenin (4',5,7-trihydroxyflavone), a flavonoid with potential cardiovascular benefits, has unclear mechanisms of action. This study investigates its effects on vascular function in Spontaneously Hypertensive Rats (SHRs). Mesenteric vascular beds (MVBs) were isolated from SHRs and perfused with increasing doses of apigenin after pre-contraction with phenylephrine. To explore the mechanisms, different MVBs were pre-perfused with antagonists and inhibitors, including indomethacin, L-NAME, and potassium channel blockers (tetraethylammonium, a non-specific potassium channel blocker; glibenclamide, an ATP-sensitive potassium channel blocker; 4-aminopyridine, a voltage-gated potassium channel blocker; charybdotoxin a selective intermediate-conductance calcium-activated potassium channel blocker; and apamin, a selective small-conductance calcium-activated potassium channel blocker). Apigenin induced a dose-dependent reduction in perfusion pressure in MVBs with intact endothelium, an effect abolished by endothelium removal. L-NAME reduced apigenin-induced vasodilation by approximately 40%. The vasodilatory effect was blocked by potassium chloride and tetraethylammonium. The inhibition of small and intermediate calcium-activated potassium channels with charybdotoxin and apamin reduced apigenin-induced vasodilation by 50%, and a combination of these blockers with L-NAME completely inhibited the effect. Apigenin promotes vasodilation in resistance arteries through endothelial nitric oxide and calcium-activated potassium channels. These findings suggest that apigenin could have therapeutic potential in cardiovascular disease, warranting further clinical research.

Comprehensive Review of Inner Ear Anatomy on Photon-Counting CT.

The inner ear contains many fissures and canals that can mimic pathology. Photon-counting CT allows greater spatial and contrast resolution of these structures over traditional energy-integrating CT detectors. Small channels containing nerves, arteries, and normal anatomy such as the cochlear cleft and cochlear and vestibular aqueducts are commonly encountered on temporal bone imaging. The improved visualization of these structures poses challenges for radiologists who are new to photon-counting CT. This article updates the existing temporal bone anatomy literature with a detailed anatomic review of the inner ear and major nerves frequently encountered when reviewing temporal bone imaging.

Morphometric analysis and watershed delineation of the Karnaphuli river basin: A comparative study using different DEMs in Chittagong, Bangladesh

AbstractThe present study aimed to delineate a robust watershed boundary and extract its morphometric parameters in the Karnaphuli watershed, Bangladesh, using different digital elevation models (DEMs). Two DEMs, the shuttle radar topographic mission (SRTM) and the terra advanced spaceborne thermal emission and reflection radiometer (ASTER), were employed to delineate watershed boundaries and evaluate various morphometric characteristics. Raster data such as fill sinks, flow direction, and flow accumulation were utilized to delineate the watershed. The morphometric analysis included the estimation of linear, areal, and relief parameters. The findings revealed a noticeable difference between the datasets; ASTER delineated a larger watershed area than SRTM. Regarding stream order, there were streams ranging from 1st to 6th order, encompassing numerous small, medium, and main channels of the river. Drainage density was calculated as 0.52 km/km² for SRTM and 0.51 km/km² for ASTER, both having a spatial resolution of 30 m. The bifurcation ratio ranged from 1.94 for SRTM to 2.45 for ASTER, indicating varying degrees of structural disturbance influenced by geological factors. The form factor indicated an elongated shape of the study area. The overall dimensions of the streams and the watershed extent suggest moderate mean annual rainfall discharge. The watershed exhibited relatively high denudation rates, attributed to the basin relief. A low drainage density indicated the importance of infiltration processes. The findings of this study provide valuable insights into the spatial variability of watershed characteristics, highlighting the need for tailored management strategies for the Karnaphuli River. Implementing targeted conservation measures and watershed management practices based on these morphometric parameters can enhance water resource sustainability and ecological health in the region.

Uranyl–Nickel(II) Cation–Cation Interaction in a Triperiodic Framework with cis‐1,2‐Cyclohexanedicarboxylate and Isonicotinate Ligands

Uranyl and nickel(II) nitrates have been reacted with cis‐1,2‐cyclohexanedicarboxylic (H2chdc) and isonicotinic (Hint) acids under solvo‐hydrothermal conditions, giving the heterometallic, mixed‐ligand complex [(UO2)2Ni(chdc)2(int)2]⋅CH3CN (1). The uranyl cation is bound to carboxylate groups of both ligands while NiII is attached to two carboxylate and two nitrogen donors, with two strong additional interactions with uranyl oxo groups giving a nearly regular octahedral environment. The short Ni–O(oxo) bond length of 2.114(3) Å amounts to 67% of the sum of van der Waals radii. The trimetallic (UO2)2Ni6+ clusters thus formed are assembled by chdc2– ligands into linear chains which are further bridged by int– links to give a triperiodic framework with the dia topology, in which small channels encompass two rows of acetonitrile solvent molecules. Complex 1 does not display uranyl luminescence under excitation in the solid state.

Channel breakdown and avulsion in arroyos feeding the Little Colorado River, Arizona, USA

Improved knowledge regarding dryland river character and behaviour is important as the increasing threats of climate change and anthropogenic activities exacerbate water security issues in channels prone to discontinuity and termination. Dryland river character and behaviour is determined by a complex and dynamic interplay between extrinsic controls and intrinsic processes. Polacca and Oraibi Wash are two discontinuous dryland rivers, tributaries of the Little Colorado River in semi-arid, north-eastern Arizona, USA. Valley-scale morphometrics and downstream longitudinal trends were derived from remote sensing and geospatial analyses, hydraulic modelling, and field measurements, to assess the key controls, patterns, and processes driving channel diminution and discontinuity. Both rivers are entrenched along most of their valleys and experience downstream hydro-geomorphic changes as valley confinement eases in their low gradient floodplains. The rivers exhibit non-equilibrium responses to a concomitant decline in calculated discharge (from ∼82 to <4 m3 s−1), stream power (from ∼334 to <5 W m−2), and channel cross-sectional area (from ∼82 to <3 m2), which are the principal factors contributing to channel breakdown and the development of broad floodouts. Small distributary channels and avulsions are evident in the lowland reaches where channel discontinuity occurs, with a dominance of knickpoints in distal floodout reaches as they attempt to re-establish channel continuity. Using historical aerial imagery we show that knickpoint headcut retreat rates have ranged from ∼1.7 to 53 m a−1. Channel breakdown patterns and processes in the Polacca and Oraibi Washes are similar to other dryland rivers around the world, and reveal common underlying factors that are central to river termination and reformation. This study reveals a combination of intrinsic erosion and sedimentation processes and avulsion threshold responses that trigger channel adjustment resulting from downstream fluvial decline. However, key extrinsic controls, such as valley confinement and hydroclimate, influence and limit the rate and nature of these adjustments. Early recognition of these geomorphic changes can inform river, land, and water management strategies across the American southwest.

A sexually dimorphic signature of activity-dependent BDNF signaling on the intrinsic excitability of pyramidal neurons in the prefrontal cortex.

Autism spectrum disorder (ASD) is a group of neurodevelopmental disorders with strong genetic heterogeneity and more prevalent in males than females. We and others hypothesize that diminished activity-dependent neural signaling is a common molecular pathway dysregulated in ASD caused by diverse genetic mutations. Brain-derived neurotrophic factor (BDNF) is a key growth factor mediating activity-dependent neural signaling in the brain. A common single nucleotide polymorphism (SNP) in the pro-domain of the human BDNF gene that leads to a methionine (Met) substitution for valine (Val) at codon 66 (Val66Met) significantly decreases activity-dependent BDNF release without affecting basal BDNF secretion. By using mice with genetic knock-in of this human BDNF methionine (Met) allele, our previous studies have shown differential severity of autism-like social deficits in male and female BDNF+/Met mice. Pyramidal neurons are the principal neurons in the prefrontal cortex (PFC), a key brain region for social behaviors. Here, we investigated the impact of diminished activity-dependent BDNF signaling on the intrinsic excitability of pyramidal neurons in the PFC. Surprisingly, diminished activity-dependent BDNF signaling significantly increased the intrinsic excitability of pyramidal neurons in male mice, but not in female mice. Notably, significantly decreased thresholds of action potentials were observed in male BDNF+/Met mice, but not in female BDNF+/Met mice. Voltage-clamp recordings revealed that the sodium current densities were significantly increased in the pyramidal neurons of male BDNF+/Met mice, which were mediated by increased transcriptional level of Scn2a encoding sodium channel NaV 1.2. Medium after hyperpolarization (mAHP), another important parameter to determine intrinsic neuronal excitability, is strongly associated with neuronal firing frequency. Further, the amplitudes of mAHP were significantly decreased in male BDNF+/Met mice only, which were mediated by the downregulation of Kcnn2 encoding small conductance calcium-activated potassium channel 2 (SK2). This study reveals a sexually dimorphic signature of diminished activity-dependent BDNF signaling on the intrinsic neuronal excitability of pyramidal neurons in the PFC, which provides possible cellular and molecular mechanisms underpinning the sex differences in idiopathic ASD patients and human autism victims who carry BDNF Val66Met SNP.

Viscoelastic liquid flow dynamics in small porous-medium channels under pressure and velocity forces

Viscoelastic liquid flow dynamics in small porous-medium channels under pressure and velocity forces

From the Northern Hajar Foothills to the Batinah Coast &amp;ndash; a Geoarchaeological Survey at Saham and Dahwa (Northern Oman)

This geoarchaeological survey was dedicated to (i) the Umm an-Nar (2700–2000 BCE) settlement site of Dahwa and surrounding areas in the foothills of the Hajar Mountains as well as (ii) the coastal area near Saham on the Batinah coastal plain in northern Oman, the latter without focus on a specific cultural epoch. Stratigraphic sections from the proximal coastal plain provide insights into highly dynamic episodic sedimentation patterns with thick units of variable grain sizes and sorting. In one of the stratigraphic profiles in the town of Saham, a small anthropogenic pit or channel was found, interpreted as a pit hearth used by the Samad culture (300 BCE–100/200 CE) based on granulometry, thin-section analysis, clustered macro-charcoals, amorphous organic remains, as well as luminescence and 14C dating. Our coincidental discovery of this site indicates that there might be abundant traces of the Samad culture buried in the thick alluvium, from a period of hydrologically favourable conditions c. 50–300 CE. The Umm an-Nar dating of the Dahwa archaeological site in the foothills of the Hajar Mountains was confirmed for the first time by luminescence dating, although the low dose rate and high scatter of equivalent doses pose substantial challenges to the regional application of this method.

Energy-saving, high-pressure resistant mini valve based on a bistable electromagnetic actuator

As core components of microfluidic and wearable pneumatic electronic systems, mini valves are attracting a growing intellectual interest. However, most existing mini valves exhibit either excessive energy consumption or limited flow rate and holding pressure. To address these issues, this study proposes an energy-saving mini valve with large flow rate and high holding pressure. The implementation of electromagnetic bistable structure allows the valve to remain open or closed without energy consumption. In contrast to the small and intricate flow channels seen in conventional mini valves, the straight-through flow channel design with reduced flow resistance improves its flow rate properties. And the pressure resistance characteristics are enhanced by the use of permanent magnetic attraction for sealing. Furthermore, the valve is driven by a single coil to switch between two steady states, resulting in a more compact structure. We have developed valve prototypes with diameters of 10 mm and 6 mm. Performance evaluation tests have shown that it sustains a holding pressure as high as 100 kPa and a flow rate of 1.5 L/min (@ 3 kPa), while only expending an energy of 0.37 J during switch transitions. Given these attributes, this valve demonstrates significant potential for integration within wearable pneumatic electronic systems.

Compressibility effects in microchannel flows between two-parallel plates at low reynolds and mach numbers: Numerical analysis

Under certain circumstances, flow in microchannels can exhibit compressibility effects even at Reynolds numbers (Re) around (below 2,300) and low Mach numbers (below 0.3). This is particularly true for gases, especially when the flow undergoes significant pressure changes or acceleration within the microchannel. This study investigates the compressibility effects encountered in two-parallel plates microchannels at these low Reynolds and Mach numbers, due to the high-pressure drop associated with the small scale of the microchannels. This uncommon flow is characterized by an exceptionally small channel diameter-to-length aspect ratio (∼10–3), resulting in a friction coefficient that deviates from the typical value for laminar flow between parallel plates (f = 96/Re). Both steady and transient effects on the flow field are examined under low Re subsonic flow, assuming continuum behavior. The ideal gas equation is used to model gas density, while the isothermal Tait-Murnaghan equation models liquid density. For gases, compressibility effects are observed primarily when the inlet pressure ratio exceeds 0.1. The results show that these effects are less pronounced for liquids, even at elevated inlet pressure ratios. Additionally, a flow delay across the channel exhibits a first-order transient response. For liquid flow, this effect depends on the channel resistance, the total fluid volume within the channel, and the liquid's bulk properties, rather than the inlet pressure ratio.

Whole-channel acoustic energy and acoustophoretic efficiency frequency spectrum by the in-flow focusing method

The in-flow focusing method, introduced herein, enables rapid and straightforward measurements of the whole-channel acoustic energy of acoustic flow-through devices. The method is applied to assess the whole-channel acoustic energy and acoustophoretic efficiency frequency spectra of a bottom-actuated silicon-glass and a side-actuated glass chip. The input variables are the time-independent geometrical shape of the particle trajectories along the manipulation chamber, the channel cross-section geometry, the physical properties of the reference particles and fluid, and the volumetric flowrate. The outputs are the total acoustic energy, the acoustophoretic efficiency, as well as the acoustic energy density distribution along the channel, which provide a comprehensive overview of the performance of acoustically driven lab-on-a-chip setups. The acoustophoretic efficiency is an important parameter that relates the energy dissipation, and therefore the heat development in the device, to the useful acoustic energy in the channel. Unlike the current state-of-the-art methods such as particle image velocimetry, particle tracking velocimetry, and optical trapping, which are typically limited to small channel areas and are time-consuming, the in-flow focusing method can be applied to long channels and enables rapid measurements of the whole-channel acoustic energy. Published by the American Physical Society 2024

Improving broadband absorption of carbon dot conjugated melanin via pre-doping strategy as interfacial photothermal evaporator

Photothermal seawater desalination harnesses solar energy to induce heat and expediates seawater evaporation and purification. The desalination efficacy heavily relies on the light absorption capability and microstructure of the solar evaporator. Polydopamine (PDA) represents a typical synthetic melanin with broad spectral absorption characteristics. However, its absorption capacity within the near-infrared (NIR) region is limited, leading to inadequate photothermal conversion efficiency. To overcome this challenge, we adopt a straightforward approach involving the pre-doping of N,S-doped carbon quantum dots (N,S-CQDs) with dopamine through covalent interaction to fabricate CQDs-loaded mesoporous polydopamine (MPDA-8). This strategy effectively reduces the band gap of PDA by fostering additional donor–acceptor pairs and π-stacking structures, thereby broadening the absorption capacity across the UV–Vis-NIR spectrum through nonradiative transitions. The MPDA-8 coated Balsa wood and cellulose evaporator achieved high evaporation rates of 1.82 kg m−2 h−1 and 2.10 kg m−2 h−1, respectively, overcoming the limit of 2D interfacial evaporator. The small pores and fiber channels within the wood, coupled with the hydrophilicity of MPDA-8, facilitates efficient water transportation and reduces evaporation enthalpy. Outdoor evaporation experiments conducted under sunlight corroborated the practical viability of this material. This study introduces a new perspective for advancing synthetic melanins in photothermal applications through the nanoparticle pre-doping strategy.

The induced non-uniformity of magnetic field enables to enhance heat transfer through the annular gap in a uniform magnetic field three – five times

We have investigated the influence of the induced non-uniformity on thermomagnetic convection when the inner cylinder of an annular gap has high magnetic permeability and a special wave-like shape. The outer uniform magnetic field induces a non-uniformity, which causes thermomagnetic convection. The problem is analyzed numerically. The in-house code uses the finite volume method with exponential interpolation functions for vorticity and temperature and linear functions for the stream function and magnetic field potential. It was found that increasing the periodicity and amplitude of the wave-like structure enhances heat transfer by 30–50 % compared to a circular annular gap filled with magnetic fluid, and 3–5 times compared to an annular gap filled with ordinary fluid. Such a way of creating induced non-uniformity of magnetic field and convection enhancement is especially effective for microfluidics, as the gravitational Rayleigh number is low in this case, and it is a hard technical problem to create a non-uniform magnetic field in small channels by directly using permanent magnets.

Hydrological and morphological responses in the São Francisco River Basin (Northeast Brazil) resulting from river damming and climate changes in a tropical region

AbstractThe São Francisco River in Northeast Brazil has seen hydrological and morphological changes due to extensive damming and climate change over the past century. In this study, we examine the influence of human activities and natural fluctuations in precipitation on the hydrological patterns of the basin and the morphological responses of the lower course of the river (LOW‐SF) to these alterations over a span of several decades. The findings indicate a decrease in water release by 41% from 1995 to 2013 and 54% from 2013 to 2018, solely attributed to human actions. Furthermore, the operation of the reservoirs of the large dams resulted in a reduction in hydrological seasonality. The changing hydrological regime caused morphological changes that resulted in an expansion of the exposed subaerial fluvial bars in the LOW‐SF and a reduction in channel width. As a result, the abandonment of small secondary channels occurred, leading to the cessation of inundation in previously buried elevated portions of bars, even during certain seasons. Another important factor was the spread of morphological changes in the LOW‐SF, which started from the areas farthest from the last dam in the series of large dams, the Xingó Dam, and spread to the nearby regions. This is due to the lack of major tributaries in the semiarid region of the LOW‐SF. The integrated assessment presented in this study illustrates both natural and anthropogenic influences. Moreover, in light of projected declines in precipitation, it is anticipated that natural phenomena could result in a substantial 73% decrease in water flow by the mid‐20th century. This climatic scenario will lead to increased utilization of hydroelectric plants and more stringent control of water flow downstream of the dam cascade, intensifying the already documented adverse effects and posing the possibility of novel morphological adaptations.

Computer Design of the Regulating Working Element of the Channel Cleaning Equipment

Cleaning devices of channel systems used for irrigation of agricultural plants and mechatronic parts regulating their operations were analyzed, the issues of automation of construction design, measurement and management in this field were examined and the purpose of the work was determined. As the goal of the work, the issue of automation of the construction design, technological measurement and management process of the working body for efficient cleaning of small and medium-sized concrete-covered channels, bathtubs from sludge and weeds was set. A complex scheme of information, algorithmic and software support for the automation of the design, technological measurement and control of the mechatronic parts of the working body used for cleaning the channel and bathtub was proposed, and the issues of logical modeling and simulation of the drawing of 2- and 3-dimensional images of the working body were solved. Algorithms were developed using the production modeling method to automate the process of technological measurement, implementation and management, which accurately regulates the operations of the working body of the mechanical device of complex construction. In Solid Edge 2D, 3D software environments, the determination of the geometric shapes of the individual mechanical parts of the channel cleaning unit with a milling cutter, their sizes and types of materials is ensured, and the algorithm was developed using the logical modeling method. For the automation of the structural design process, the information security of the mechanical parts of the application object and the elements of the new design milling cutter device was created for the management of the database of drawings.

Construction of 2D zinc(II) MOFs with tricarboxylate and N-donor mixed ligands for multiresponsive luminescence sensors and CO2 adsorption.

The solvothermal reactions of ZnCl2·6H2O, benzene-1,3,5-tribenzoic acid (H3btb), and N-heterocyclic ancillary imidazole (Im) or aminopyrimidine (a mp) ligands led to the creation of two-dimensional (2D) zinc(II) based metal-organic frameworks (MOFs), (Me2NH2)2[Zn2(btb)2(Im)2]·2DMF·3MeOH (1) and (Me2NH2)2[Zn2(btb)2(amp)]·H2O·2DMF·MeOH (2). The btb3- ligands in 1 and 2 form an anionic 2D layered structure with a (63) honeycomb (hcb) topology by linking to Zn(II) centres through their carboxylate groups. The incorporation of N-heterocyclic auxiliary ligands Im and amp into the hcb nets resulted in the formation of a 2D hydrogen-bonded and covalently pillared bilayer structure featuring two-fold interpenetrating networks. Each of these networks consists of small channels that are occupied by Me2NH2 cations and solvent molecules. Both 1 and 2 emit blue luminescence emissions in the solid state at room temperature and exhibit a great selectivity and sensitivity for the detection of acetone and multiple heavy metal ions including Hg2+, Cu2+, Fe2+, Pb2+, Cr3+, and Fe3+ ions. At 1 bar, activated 1 and 2 demonstrate moderate capacities for adsorbing CO2 at room temperature, with a preference for CO2 over N2. Notably, at higher pressures (up to 20 bar), their activated samples 1 and 2 show a temperature-dependent enhancement of CO2 uptake while retaining good stability.

Thermal performance of a novel hybrid heat pipe with composite heat transfer characteristics

Considering the capillary threshold of oscillating heat pipes (OHP), a novel hybrid heat pipe (HHP) was designed with channels with hydraulic diameters that alternately exceed and fall below this threshold, parallelly arrayed within a unified copper substrate. This technology attains a comprehensive heat transfer performance within the HHP, seamlessly transitioning from pure phase change heat transfer to hybrid pulsating flow heat transfer to effectively accommodate the escalating demands of heat load. Performance and visualization are used to analyze the operational characteristics of HHP. The results indicate that the HHP mainly transfers heat through the phase change in the large channels in lower heat input, while the working fluid in the small channels remains calm. Once the heat input is sufficient, the geyser boiling in the large channels and the liquid slug pulsating in the small channels jointly carry out heat transfer. Furthermore, the liquid content in the large and small channels can be adaptively adjusted to each other. The high-speed liquid in the small channels can be squeezed into the large channels to ensure the sufficient pulsating space and achieve efficient heat transfer under high heat input. In addition, the operation of the HHP can be significantly impacted by the filling ratio (FR). In the phase change stage, the FR of 47.6 % can be considered as the turning point. After transitioning to the hybrid pulsating flow stage, the HHP with low FR can get a better performance. This new type of heat pipe with gradually changing operation characteristics may be critical to solve thermal problems in variable heat load domain.