Open Hole Research Articles

A 3D printed acoustofluidic nozzle-diffuser microfluidic pump

Microfluidic flow control systems are critical components for on-chip biomedical applications. This study introduces a new micropump for on-chip sample preparation and analysis by using an acoustic nozzle diffuser mechanism. The micropump implements a commercially available transducer and control board kit with 3D-printed fluid reservoirs. In this micropump, conic-shaped micro-holes on the metal sheet cover of the transducer are employed as oscillating nozzle diffuser micro arrays to achieve directional flow control. The micropump is shown to efficiently pump water and particle mixtures exceeding flow rates of 515 µl/min at a 12-volt input voltage. In addition, owing to the small size of the nozzle hole opening, larger particles can also be filtered out from a sample solution during fluid pumping enabling a new function. Importantly, the micropump can be fabricated and assembled without needing a cleanroom, making it more accessible. This feature is advantageous for researchers and practitioners, eliminating a significant barrier to entry. By combining commercially available components with 3D printing technology, this micropump presents a cost-effective and versatile solution for on-chip applications in biomedical research and analysis.

Hole size influence on the open hole tensile and flexural characteristics of aramid-basalt/epoxy composites

Hole size influence on the open hole tensile and flexural characteristics of aramid-basalt/epoxy composites

METHODOLOGY FOR EXPERIMENTAL RESEARCH OF THE FIRE HAZARD OF POWER LITHIUM-ION BATTERIES OF ELECTRIC VEHICLES UNDER THE INFLUENCE OF A HEATING PANEL

Even though lithium-ion batteries (LIBs) are the subject of various tests and research at the production stage, there are no isolated cases of electric vehicle fires, and the development dynamics are unpredictable. The particular danger of such fires lies in the oxygen release during an irreversible exothermic reaction in LIBs, which creates new challenges for fire and rescue services when extinguishing such fires. The study aims to develop the main provisions of the methodology for experimental studies of electric vehicle power batteries in terms of fire hazards using an electric heating panel. The ultimate goal of the study is to determine the temperatures at which an irreversible exothermic reaction, the opening of ventilation holes, and the combustion (explosion) of electric vehicle power batteries begin, as well as the time parameters at which such processes occur. Taking into account the peculiarities of the occurrence and course of the irreversible exothermic reaction, we have developed a methodology, the essence of which is to determine the temperatures of the onset of the irreversible exothermic reaction of the electric vehicle power battery, the opening of ventilation holes, and the combustion (explosion) of electric vehicle power batteries, the combustion temperatures of ventilation gases, as well as the time parameters at which these processes occur, which may change during battery operation and not correspond to the declared parameters of the manufacturer. For this purpose, we exposed LIBs to thermal energy from an electric heating panel and recorded the temperature and time during which an irreversible exothermic reaction occurs from the moment of an internal short circuit to a fire or explosion. The use of the proposed methodology of experimental studies of the elements of power batteries of electric vehicles regarding the fire hazard of an electric heating panel will make it possible to determine the temperature limits of the occurrence of irreversible exothermic reactions in LIBs, as well as the time parameters under which these processes occur. Keywords: electric vehicle fire, irreversible exothermic reaction, lithium-ion battery.

Ramie Fiber Woven Composite: The Effect of Number of Layers of Woven Fibers on the Thrust Force in the Drilling Process

Composite material is a combination of two or more materials to obtain better properties and capabilities of the constituent materials. Applications for the use of composites can now be found in industrial equipment to household appliances. To produce these products required machining process. The aim of the study was to determine the effect of the number of layers of woven fiber and the diameter of the drill bit on the thrust of the ramie woven fiber composite in the machining process. The research method was based on ASTM D 5766/D 5766M-02 (Standard Test Method for Tensile Strength Open Hole Laminated Polymer Matrix Composites), the method of making composite material specimens using the hand lay-up method, and the drilling process was carried out with various machining parameters such as composite thickness with variations of 3 layers, 4 layers, 5 layers, and without layers (0 layers). The maximum thrust value obtained was 153.54 ± 3.3 N, with 5 layers of hemp fiber reinforcement, the highest feed rate was 0.15 mm/rev, and the lowest spindle speed was 88 rpm, while the minimum thrust value was 29.52. ± 3.12 N with 0 layers of ramie fiber reinforcement, and the lowest feed rate is 0.05 mm/rev with the highest spindle speed of 1500 rpm.

Influence of Size of Open Hole on Stability of Compressed Plate Made of Carbon Fiber Reinforced Polymer

Influence of Size of Open Hole on Stability of Compressed Plate Made of Carbon Fiber Reinforced Polymer

Delamination mechanism in CF/EPOXY with open hole under mode II loading at different distances

This research addresses limitations in current aviation composite assembly techniques, often constrained by certification challenges. To enhance bonded composite components, open holes are frequently introduced, leading to increased vulnerability to delamination, a prominent failure mode in composite laminates. This study focuses on observing the impact of open holes on the mode II behavior of composites under various distances and hole diameter conditions. Results illustrate distinct load–displacement curves influenced by hole size, with shorter distances accelerating crack propagation, evidenced by reduced elastic regions and lower load values. Analyzing specimen appearances and crack patterns highlights stress concentration at the hole, influencing initiation and propagation. In the absence of a hole, cracks exhibit a zig-zag pattern near the loading point, while with a hole, they concentrate around it. Elastic region length varies with the pre-crack-to-hole distance, indicating accelerated crack propagation in shorter distances. This study underscores the direct influence of hole size on load values, emphasizing its pivotal role in determining composite mechanical properties. This research provides valuable insights into hole characteristics’ interplay with delamination behavior in carbon fiber-reinforced composites, essential for optimizing aerospace component design and structural integrity.

Analysis of Surge and Swab ECD of Herschel Bulkley Fluids in Rumaila Iraqi Oil Field

Surge and swab pressures are frequently produced during various stages of well construction, including casing running and tripping operations. Managing downhole pressure within the mud window is crucial for mitigating the risks associated with drilling operations including wellbore failure, lost circulation, kicks, and well control issues. The primary objectives of this study are to emphasize the theoretical foundation of surge and swab pressures, forecast the optimum pipe and casing tripping speeds, as well as identify the changes in surge and swab pressures (i.e., equivalent circulating density-ECD) for both open-ended and close-ended drill strings. To achieve these goals, a steady state surge and swab model was used to simulate a case study in the Rumaila oil field, located in Southern Iraq, by utilizing landmark-well plan software. The results of this study support the evidence that the string trip speed plays a substantial role in controlling the swab and surge pressures. It was found that pulling out the 5" drill string from the 12 1/4" open hole section drilled with a 9.51 ppg water-based mud at a speed of 10 sec/stand resulted in a swab ECD below the formation pore pressure against all formations, thus resulting in a kick. Moreover, it was found that the annular clearance had a significant impact on the surge and swab ECD whereas the surge ECD at the bit was bigger than that obtained at the previous hole casing shoe. For example, in our case study pulling speeds ranging from 10-190 sec/stand for the 9 5/8" casing could cause the swab ECD to be below the formation pore pressure gradient at total depth (TD), which is 9.23 ppg. While it was safe to run the same casing through the same interval within 55-190 sec/stand. Furthermore, the results emphasized high trip speeds ranging between 10-30 sec/stand, where for close-ended drill strings, greater surge ECD was observed compared to the open-ended ones. The surge ECD of a 5" close-ended drill string at 30 sec/stand (60 m/min) at bit was 9.92 ppg, while an open-ended string at the same speed was 9.9 ppg.

Transportation conditions of calves upon arrival at major livestock auction markets in Québec, Canada

The objective of this cross-sectional observational study was to describe the transport conditions of calves at the time of their arrival at the 2 major livestock auction markets in the province of Québec, Canada, and to identify characteristics that affect bedding cleanliness. A particular emphasis was placed on the transport environment of young dairy calves commonly being marketed for veal production. During 4 d per auction site (n = 2 sites), 2 d in summer and 2 d in winter, the descriptive characteristics including type of transports, number of calves per transport, separation from other transported animals, as well as presence of ventilation sources (e.g., open holes allowing natural ventilation), bedding, and bedding cleanliness, were determined. A total of 507 different transports were included, representing a total of 4,054 calves sold during these 8 d. The vast majority of calves (95% [n = 3,845]) were transported by commercially designed trailers (long commercial trailers (n = 358; 70.6% of all transport types), short commercial trailers (n = 62; 12.2%), or multideck trailers (n = 15; 3%). A minority of calves (5%) were either transported by homemade trailers (n = 30; 5.9% of transport) or other types of transports (n = 42; 8.3%). The presence of any ventilation source in the calves' transportation area was observed in 86% of transports and increased in summer versus winter (odds ratio: 2.75 [95% CI: 1.58–4.79]). Bedding was present in 96% of evaluated transports. The majority (68%) of calves' transport flooring area was considered clean, with less than 33% of the calves' area soiled with manure. The dirtiness of calves' transport flooring area was lower in winter than in summer (odds ratio = 0.63 [0.43–0.92]) and in site B than in site A (odds ratio = 0.57 [0.38–0.94]). This study gives interesting insight into transportation and unloading conditions of surplus calves in commercial auction markets.

Solver-free reduced order homogenization for nonlinear periodic heterogeneous media

Reduced-order homogenization (ROH) and related methods are important computational tools for simulating the material behavior of composites. These methods generally sacrifice accuracy in exchange for superior computational efficiency, relative to methods such as classical computational homogenization (CCH). In this study, building on the recently developed solver-free CCH, we propose a fine-scale solver-free reduced order homogenization approach that avoids solving the fine-scale equilibrium equations and approximates the phase-average eigenstrains by sampling the fine-scale eigenstrain at a small number of points. The proposed method, which we call solver-free ROH, works by pre-computing history-dependent eigenstrain influence function tensors and sampling point contribution factors based on training data from a small set of CCH simulations. Then, during the online stage of the computation, phase-average eigenstrains are computed from sampling point eigenstrains and used to compute homogenized stresses and strains. Focusing on small-deformation problems, this paper formulates and verifies the solver-free ROH approach for nonlinear periodic heterogeneous media. First, in the formulation, we delineate a sampling point approximation of the phase eigenstrains and describe the use of this approximation within the coarse-scale stress update. Next, we verify the solver-free ROH using loading cases outside the training data set. Finally, we use the proposed method to simulate a multilayer composite plate in three point bending (3pt-bend) and open hole tension (OHT), demonstrating the method’s efficiency and accuracy relative to the CCH.

Assessing the hazard of fault triggering by deep geothermal energy production in an active fault system via a 1D stress model and 3D fault mapping

Borehole image data and a 1D-stress model built on open hole logs, leak-off tests (LOT) and image logs are used to evaluate the potential of seismicity caused by fault triggering during geothermal heat production in the city of Vienna. Data were derived from a 4220 m deep geothermal exploration well that investigated the geothermal potential of fractured carbonates below the Miocene fill of the Vienna Basin. The well penetrated several normal faults of the Aderklaa Fault System (AFS) that offset Pleistocene terraces at the surface and hence are regarded as active. Stress-induced borehole failures and 1D geomechanical modeling proves that the potential reservoirs are in a normal fault stress regime with Sv > SHmax > Shmin. While stress magnitudes in the upper part of the well (down to about 2000 m) are significantly below the magnitudes that would trigger the rupture of critically oriented faults including the AFS, stresses in the lower part of the drilled section in the pre-Neogene basement (below about 3300 m) are not. Data evidence a rotation of SHmax for about 45° at a fault of the AFS at 3694 m to fault-parallel below the fault suggesting that the fault is active. Critical or near-critical stressing of the fault is corroborated by the stress magnitudes calculated from the 1D geomechanical model. The safety case to exclude unintended triggering of seismic fault slip by developing geothermal reservoirs in close vicinity to one of the branch faults of the AFS may therefore be difficult or impossible to make.Graphical

Experimental evaluation on compression-after-impact behavior of perforated sandwich panel comprised of foam core and glass fiber reinforced epoxy hybrid facesheets

Abstract To study the impact response and compression-after-impact (CAI) behavior of perforated sandwich panels comprised of foam core and glass fiber-reinforced epoxy hybrid facesheets, the hole diameter of specimens is changed in the fabrication via vacuum-assisted resin infusion. Furthermore, low-velocity-impact tests with various impact distances between the impact point and hole are carried out. With the help of the digital image correlation technique, CAI testing is conducted, and the strain evolution of specimens is monitored carefully. The mechanical response history, damage morphology, and compressive process are discussed in detail. The results show that the impact and CAI performance of specimens are weakened because of open holes. Compared with the non-perforated specimen, the maximum force of the specimen with a 6-mm hole and the 5-mm impact distance decreases by 41.21%, and its maximum displacement increases by 38.60%. During the CAI process, in comparison with the impact damage, more significant stress concentration and buckling around the hole are found.

Study on the Hole-Forming Performance and Opening of Mulching Film for a Dibble-Type Transplanting Device

In order to improve the quality of transplanting devices and solve the problems of the poor effect on soil moisture conservation and more weeds easily growing due to the high mulching-film damage rate with an excessive number of hole openings, we developed a dibble-type transplanting device consisting of a dibble-type transplanting unit, a transplanting disc, and a dibble axis. The ADAMS software Adams2020 (64bit) was used to simulate and analyze the kinematic track of the transplanting device. The results of the analysis show that, when the hole opening of the envelope in the longitudinal dimension was the smallest, the transplanting characteristic coefficient was 1.034, the transplanting angle was 95°, and the transplanting frequency had no influence. With the help of the ANSYS WORKBENCH software Ansys19.2 (64bit), an analysis of the process of the formation of an opening in the mulching film and a mechanical simulation of this process were completed. The results indicate that, when the maximum shear stress of the mulching film was the smallest, the transplanting characteristic coefficient was 1.000, the transplanting frequency was 36 plants·min−1, and the transplanting angle was 95°. In addition, the device was tested in a film-breaking experiment on a soil-tank test bench to verify the hole opening in the mulching film. The bench test showed that, when the longitudinal dimension was the smallest, the transplanting characteristic coefficient was 1.034, the transplanting frequency was 36 plants·min−1, and the transplanting angle was 95°. When the lateral dimension was the smallest, the transplanting characteristic coefficient was 1.034, the transplanting frequency was 36 plants·min−1, and the transplanting angle was 90°. The theoretical analysis, kinematic simulation, and soil-tank test results were consistent, verifying the validity and ensuring the feasibility of the transplanting device. This study provides a reference for the development of transplanting devices.

The Effect of Air Flow and Stirring Frequency in Continuous Thermophilic Composting

Continuous Thermophilic Composting (CTC) was developed as a modification of continuous composting carried out in the thermophilic phase, where the organic waste degradation process runs quickly. Previous CTC research used lamps as a heat source, which was then changed to use a heater. Several important factors in composting are stirring and air circulation to increase oxygen levels so that the aerobic composting process occurs. The machine has been modified by making air holes and setting automatic stirring. This research aims to determine the air hole openings and stirring frequency that provide the best results. The research was carried out in 2 stages. The first stage is to look for air hole openings with 3 variations: closed, half open, and fully open. Continue by finding the best stirring frequency with 3 variations: once a day, 2 times a day, and 6 times a day. The parameters measured include temperature measured humidity and pH during the composting process, and chemical analysis of fresh waste, compost starter, and mature compost resulting from the process. The research was carried out for 8 days with the addition of 1 kg of artificial waste per day. The results showed that half-open air holes produced better compost quality and temperature consistency in the thermophilic phase. And the stirring frequency of 2 times a day produces consistent temperature results in the thermophilic phase and compost quality that meets SNI 19-7030-2004 of Compost Specifications from Domestic Organic Waste.

Performance optimization of PERC solar cells based on laser ablation forming local contact on the rear

Abstract To improve the photoelectric conversion efficiency (η) of the solar cell, a green wavelength (532 nm) laser source in a nanosecond range was used to ablate the passivated emitter and rear cell (PERC) to form the contact holes. If the laser ablation hole opening process was not set properly, the diameter or the external expansion of holes would be too large, causing the decline of the PERC performance. The Gaussian distribution of the laser is regulated by the output power (P o) and the repetition frequency (f rep) of the incident pulse laser, so that the optimized morphology of holes is obtained on the back of the PERC solar cells. After the contact holes are screen printed by the aluminum paste, the local back surface field is finally formed. The experimental results showed that the outward expansion decreases obviously with the increase of laser P o. Second, the spacing of the holes decreases with the increase of the laser f rep. It was found that under the laser P o of 33.0 W and f rep of 1,400 kHz, the η of the industrial PERC solar cells was the highest. The Quokka simulations indicated that small outward expansion, small diameter, and long spacing of holes would further decrease the recombination parameter in the rear surface. With the optimized morphology of contact holes and the low contact resistance, the PERC cell’s calculated V oc and η improvements were 6.5 mV and 0.48%, respectively, which was verified with experimental findings.

One-dimensional acoustic modeling of the şimşal considering the external Interaction of the open finger holes

A one-dimensional model in Python was developed to analyze the acoustic behavior of the Kurdish wind instrument, the şimşal. This model was developed using the Transmission Matrix Method (TMM), which was refined by taking into account the external interactions between the open tone holes. This research focuses on the acoustic resonator part of the şimşal with the lattice of finger holes in different cross-fingering patterns. The results were validated by measurements using an impedance probe, CapteurZ, which was developed by LAUM[1] and CTTM[2] The results are in good agreement with the measurement and despite the possible sources of error, which are discussed, the deviations are within an acceptable range. [1] The Acoustics Laboratory of the University of Le Mans [2] Le Mans Technology Transfer Center.

Spectral behavior of recorder tones during transitions between notes

We have studied note transitions in a soprano recorder as tone holes are opened or closed. Experimental results with an instrument excited by an artificial blowing machine are compared to Navier-Stokes-based simulations for an essentially identical instrument geometry. Several different cases have been studied. (1) Transitions involving the opening or closing of a single tone hole, with the notes separated by two semitones; e.g., transitions between C5 and D5. (2) Transitions involving the opening or closing of several tone holes simultaneously; e.g., transitions between C5 and G5. (3) Transitions involving a single tone hole but for notes separated by a major fifth; transitions between C5 and G5 using a forked fingering. Our work has focused on tone hole openings and closings at speeds typical of a human player but interesting behavior was also observed for longer tone hole switching times for cases (2) and (3), in which the sound field inside and outside the instrument was found to take much longer than the tone hole switching time to reach steady state. Work supported by NSF grant PHY2306035

Study of the Load-Bearing Capacity of Composite Structures with Various Reinforcement Patterns in the Zone of the Open Hole

Study of the Load-Bearing Capacity of Composite Structures with Various Reinforcement Patterns in the Zone of the Open Hole

Analysis of the Effect of an Open Hole on the Buckling of a Compressed Composite Plate.

This paper investigates the effect of an open hole on the stability of a compressed laminated composite plate. The study was carried out in two ways: using experimental tests and numerical analysis. As a result of the experiment, the buckling form and path of the plate were recorded. The form of buckling was determined using the ARAMIS non-contact measurement system. The critical load value was determined from the working path using the approximation method. The experimental results were verified by numerical analysis based on the finite element method. FEM investigations were carried out in terms of a linear eigenproblem analysis. This allowed the bifurcation load and the corresponding buckling form of the numerical model of the plate to be determined. Investigating the effect of the hole in the compressed plate at a critical state showed high agreement between the proposed test methods. No clear effect of the hole size on the buckling of the plate was observed. In contrast, a clear effect of the hole on the critical load value was determined. The maximum decrease in the critical load value was 14%. The same decrease was observed for the stiffness of the post-critical characteristics. It was shown that the [45|-45|90|0]s composite plate had more than three times lower strength compared to [0|-45|45|90]s and [0|90|0|90]s. The novelty of this article is the development of a research methodology based on new interdisciplinary research methods for describing the influence of the central hole on the stability of compressed composite plates. The ABAQUS system was used for the numerical analysis.

Research on New Whitening and Water-Saving Technology Based on Industrial Equipment

Energy conservation and consumption reduction have always been the goals pursued by the power industry. Based on these goals, this study explored a new type of whitening and water-saving technology for industrial equipment. Unlike existing direct heating and condensation heating technologies, the main innovation of this work lies in not changing the saturated wet flue gas before it is discharged into the atmospheric environment. A series of experiments were conducted on electrode plates with different wind speeds, supersaturation levels, and porosities using three principles, namely droplet electrostatic adsorption, ionic-wind-enhanced condensation, and droplet dipole deflection, through the construction of a parameter-adjustable and -controllable enthalpy and humidity chamber and a pilot development platform with a wind volume of 10,000 m3/h. In addition, the collection efficiency was calculated using thermodynamic laws. The results showed that, under the working conditions of white mist supersaturation of 5.77 g/kg, a hole opening rate of 70%, and a wind speed of 3 m/s, the water collection efficiency was the highest—close to 60%—verifying the feasibility of this technology. This technology not only eliminates white smoke but also saves water resources and has certain economic benefits, providing support for the development of industrial equipment for smoke removal in the future.

Analysis of Fluid Field in Fish Tank of Breeding Vessel with Perforated Broadsides under Wave Conditions

For a fish tank of breeding vessels with perforated broadsides, in order to analyze its fluid characteristics under wave conditions, this paper presents a numerical method and predicts the fluid field in a fish tank with opening holes. Therein, three critical problems were solved, which include wave generation, the fluid–structure interaction of waves and vessel motion, and the sloshing phenomenon in the tank. The feasibility of the method was validated through a comparison with theoretical and experimental results. On this basis, the fluid characteristics in the fish tank of a fixed breeding vessel with opening holes on side walls were discussed. Firstly, the effects of wave direction, wave height, and wave period on the flow field in the tank were mainly analyzed. Next, the fluid characteristics in the tank of a floating vessel with opening holes equipping a multi-point mooring system were investigated. Finally, the influence of motion responses of breeding vessels on the fluid field in the fish tank was examined.