Experimental Investigation Research Articles

An experimental investigation on the flow control of the partially stepped NACA0012 airfoil at low Reynolds numbers

An experimental study of flow control around a NACA0012 airfoil modified with fully and partially step geometry was conducted at Reynolds numbers of 6 × 104 and 1.2 × 105. Partially step geometries, the location of the step on the airfoil, and Reynolds number are varied to show their effect on aerodynamic performance and flow structures on the airfoil. Experimental results show that fully and partially step geometries are effective for flow control around the airfoil and aerodynamic performance enhancement. The maximum increase in lift coefficient is approximately 46%, and the stall angle is shifted about 1° by the SM4 model at Re of 6x104 while the step geometry is on the pressure side. For a Reynolds number of 1.2 × 105, the highest increase in the lift-to-drag ratio of the airfoil is observed about 17.1 at an angle of attack of 6° by the SM2 model when step geometry is placed on the pressure side of the airfoil. In the event of partially or fully stepped at the pressure side of the model, step flow structures, including the reattachment line, recirculation zone, and corner eddy, are obtained. However, even though the step geometry is at the suction surface of the model, the formation of a laminar to turbulent transition is observed. The overall results suggest that the partially stepped geometry length, Reynolds number, and step location side on the airfoil have an important role in flow control to improve aerodynamic performance for various angles of attack.

Experimental investigation on structural behaviour of castellated column under axial load

Experimental investigation on structural behaviour of castellated column under axial load

Experimental Investigation on the Effects of Microwave Irradiation in Pore Structures of LN2 Freezing Coal for Coalbed Methane Extraction

Experimental Investigation on the Effects of Microwave Irradiation in Pore Structures of LN2 Freezing Coal for Coalbed Methane Extraction

Experimental investigation on the mechanical behavior and fracture mechanism of sandstone after heat treatment

Experimental investigation on the mechanical behavior and fracture mechanism of sandstone after heat treatment

Study on the effects of inorganic salts and ionic surfactants on the wettability of coal based on the experimental and molecular dynamics investigations

Through the evaluation and preparation of a novel inorganic salt composite solution consisting of sodium dodecyl benzene sulfonate (SDBS), the nonionic surfactants polyethylene glycol pisooctyl phenyl ether (Triton X-100), and inorganic salt Na2SO4, based on surface tension, contact angle, settling time, wetting rate, and changes in the surface microstructure and functional groups of coal, this study analyzed the wetting behavior of the solution on coal dust and its adsorption capacity on the surface of coal particles. The results demonstrate that the composite solution of inorganic salts can significantly enhance the wettability of coal samples, reducing the contact angle to 21.54° and lowering the surface tension to 26.10 mN/m. After treatment with the solution, the relative content of oxygen-containing functional groups in the microscopic structure of the coal sample increased to 59.6 % and pores more prominent than 25 nm increased to 34.63 %. Molecular dynamics (MD) simulations of the water-inorganic salt composite solution-coal system are conducted using Materials Studio software, revealing that after the addition of the composite solution, the self-diffusion coefficient (D) of water molecules is 6.3 × 10-9 m2/s, the starting point of the composite solution is 15 Å, and the system's interaction energy increase to 14000 kcal/mol. It further elucidated the modification of the surface molecular structure of coal dust by the inorganic salt composite solution, increasing hydrogen bonds, enhancing wetting, and demonstrating a solid adsorption capability of the inorganic salt composite solution on the surface of coal dust.

The Effectiveness of Emotionally Focused Couple Therapy Training (Hold Me Tight) on Couples' Emotional Abuse

Aim: The aim of this study was to determine the effectiveness of Emotional Couple Therapy Training (Hold Me Tight) on couples' emotional abuse. Methods: The current study was an experimental ABA single-subject design investigation. The statistical population consisted of all couples who had attended counseling centers in city of Bojnord (Iran) during 2021. From this population, three couples who had met the inclusion criteria were purposefully selected. The Emotional Abuse Scale (EAS) was used to collect data in three stages (baseline, intervention, and follow-up). The intervention consisted of the emotional couple therapy training (hold me tight) that was administered in eight 120-minute sessions for each of the 3 pair of couples. Data analysis primarily included visual analyses, such as level, trend, and variability at three stages of baseline, intervention, and follow-up, both as within-condition, and between-condition layers. Findings: Results showed that the emotional couple therapy training (Hold Me Tight) is effective in reducing emotional abuse. The effectiveness of the results lasted for two months after the intervention. Conclusion: Given the effectiveness of emotional couple therapy, therapists are recommended to draw on this protocol to help couples struggling with emotional problems such as abuse and violence.

Experimental investigation for in-situ hydrogen production by electrochemical reforming of glycerol

In this paper, hydrogen production from glycerol have been investigated in a cubic electrolysis cell with/without membrane and in the system with membrane electrode assembly (MEA). Membrane and electrode effects on hydrogen production were examined in the electrolysis cell originally designed and manufactured. A constant current density value of about 10 mA/cm2 was recorded in the electrochemical reforming of glycerol in acidic electrolyte conditions in the system using Nafion 117 membrane at room temperature under 2 V constant potential. The highest current density value was reached in the case where the oxidation of glycerol at the anode occurred on the Zn electrode and the hydrogen evolution reaction at the cathode occurred on the Pt electrode. The current density value increased by 24 % using a Pt electrode instead of Zn at the cathode. According to the results of the cathode peak area in the gas chromatography analysis, the highest hydrogen formation was recorded under these conditions. To create MEA, 5.7 mg/cm2 10 % Pt/C (0.57 mg/cm2 Pt) and 5 mg/cm2 Zn were loaded for the cathode and anode respectively. A nozzle-type current collector made of copper material was selected among the current collectors of different geometries and materials used in the electrochemical reforming of glycerol. A constant current density value of approximate 500 mA/cm2 was achieved under the specified conditions and with diverse system improvements.

New Insights in ATP Synthesis as Therapeutic Target in Cancer and Angiogenic Ocular Diseases.

Lactate and ATP formation by aerobic glycolysis, the Warburg effect, is considered a hallmark of cancer. During angiogenesis in non-cancerous tissue, proliferating stalk endothelial cells (ECs) also produce lactate and ATP by aerobic glycolysis. In fact, all proliferating cells, both non-cancer and cancer cells, need lactate for the biosynthesis of building blocks for cell growth and tissue expansion. Moreover, both non-proliferating cancer stem cells in tumors and leader tip ECs during angiogenesis rely on glycolysis for pyruvate production, which is used for ATP synthesis in mitochondria through oxidative phosphorylation (OXPHOS). Therefore, aerobic glycolysis is not a specific hallmark of cancer but rather a hallmark of proliferating cells and limits its utility in cancer therapy. However, local treatment of angiogenic eye conditions with inhibitors of glycolysis may be a safe therapeutic option that warrants experimental investigation. Most types of cells in the eye such as photoreceptors and pericytes use OXPHOS for ATP production, whereas proliferating angiogenic stalk ECs rely on glycolysis for lactate and ATP production. (J Histochem Cytochem XX.XXX-XXX, XXXX).

Laboratory investigation and prediction of permeability of fresh to five-year-old municipal solid wastes of low and high food contents

The permeability of municipal solid wastes (MSWs) is important for the design and operation of landfills. This study presented the experimental investigation of the permeability of low food content- (LF-) and high food content- (HF-) MSWs prepared in laboratory-scale bioreactors for up to 5 years. The permeability of MSWs with diverse degrees of decomposition (DOBs), void ratios, and permeation liquids was measured (288 tests). The measured permeability was compared to that predicted from the (modified) Kozeny-Carman (K-C) equations in four different forms. The results indicated that the permeability of both LF- and HF-MSWs decreased significantly (p < 0.05) with decomposition under a given void ratio. The predicted permeability using the original K-C equation fitted well with that of fresh MSWs. The permeability of decomposed MSWs was closer to the predicted results using the modified K-C equation with the effective void ratio. This can be attributed to the increase in the fine fractions due to degradation. The reduction in the effective voids was more significant with HF-MSWs. The parameters required in the (modified) K-C equations showed a good correlation with DOB and effective particle size (d10). The predicted permeability based on the relationship between DOB (or d10) and equation parameters was within 3 times the difference compared to the measured values. The above results indicated that the modified K-C equation can be adopted to predict the permeability of fresh and degraded MSWs while more field-scale experiments should be conducted to further evaluate its feasibility.

Simulation and Experimental Investigation of a Combined Control Method for Stray Grain During Single Crystal Blade Solidification

Simulation and Experimental Investigation of a Combined Control Method for Stray Grain During Single Crystal Blade Solidification

Experimental Investigation on the 3D Printing of Nylon Reinforced by Carbon Fiber through Fused Filament Fabrication Process, Effects of Extruder Temperature, and Printing Speed

This study investigated how the extruder temperature, printing speed, and specimen geometry interact during a tensile test of continuous carbon fiber-reinforced nylon matrix composites produced by the fused deposition modelling (FDM) process. The investigation utilized statistical techniques. For this purpose, tensile examinations were done on manufactured samples using a testing apparatus. The study’s objective is to identify the most efficient specimen geometry for tensile testing result optimization and to maximize the 3D printing process’s capability for producing complex, freeform patterns in these composites. In this study, the input parameters required for the response surface methodology (RSM) were varying extruder temperature (240-255°C) and printing speed (60-80 mm/s), and experimental responses included modulus, elongation at break, and weight. The findings of the regression analysis showed output responses are influenced by both input variables. The results showed that the strength of the samples was significantly influenced by the input parameters. To draw the surface and residual plots, the software of design expert software was used. The interaction between the two input variables suggests raising the extruder temperature and decreasing printing speed, which leads to printing heavier samples. Inversely, the diversity between the forecasted and real responses for the optimal specimens is less than 10% which is assumed to be acceptable for the design of experiments (DOE). The analysis took into account the lower and upper ranges of the input variable with the goal of enhancing both the most modulus and fracture elongation while simultaneously degrading the weight of the specimens. To achieve this objective, the extruder temperature and printing speed are between 240 and 250°C and 65 and 75 mm/s, respectively.

Impact of colloidal properties of cupric oxide-water nanofluid on cooling of miniaturized systems: a numerical and experimental investigation

Impact of colloidal properties of cupric oxide-water nanofluid on cooling of miniaturized systems: a numerical and experimental investigation

Regulating the Topology of Covalent Organic Frameworks for Boosting Overall H2O2 Photogeneration

AbstractPhotocatalytic oxygen reduction reactions and water oxidation reactions are extremely promising green approaches for massive H2O2 production. Nonetheless, constructing effective photocatalysts for H2O2 generation is critical and still challenging. Since the network topology has significant impacts on the electronic properties of two dimensional (2D) polymers, herein, for the first time, we regulated the H2O2 photosynthetic activity of 2D covalent organic frameworks (COFs) by topology. Through designing the linking sites of the monomers, we synthesized a pair of novel COFs with similar chemical components on the backbones but distinct topologies. Without sacrificial agents, TBD‐COF with cpt topology exhibited superior H2O2 photoproduction performance (6085 and 5448 μmol g−1 h−1 in O2 and air) than TBC‐COF with hcb topology through the O2‐O2⋅−‐H2O2, O2‐O2⋅−‐O21‐H2O2, and H2O‐H2O2 three paths. Further experimental and theoretical investigations confirmed that during the H2O2 photosynthetic process, the charge carrier separation efficiency, O2⋅− generation and conversion, and the energy barrier of the rate determination steps in the three channels, related to the formation of *OOH, *O21, and *OH, can be well tuned by the topology of COFs. The current study enlightens the fabrication of high‐performance photocatalysts for H2O2 production by topological structure modulation.

Effects of Channel Flow Blockage on Metal Foam Heat Transfer

Abstract High porosity aluminum foams have the potential to dissipate large heat flux in a channel flow configuration due to their large surface area-to-volume ratio and the ability to enhance mixing due to flow tortuosity. It is well documented that the interstitial heat transfer coefficient has a power law dependence on the flow velocity at the pore-scale. For asymmetrical heating (single wall), a flow blockage concept is proposed with an aim to locally enhance flow speed near the heated wall. To this end, experimental and numerical investigation is carried out on a high porosity (95%) aluminum foam (10 pores per inch) with flow blockages, both upstream and downstream of the metal foam placed in a square channel. The opening was provided closer to the heated wall, where flow blockage was varied from 0% to 87%. With air as working fluid, experiments were conducted for channel Reynolds number varying from 3000 to 13,000. It was found that all flow blockages resulted in enhanced heat transfer over no-blockage case, however, at a high pressure drop penalty. An upstream flow blockage of 70% was found to have the highest thermal-hydraulic performance among other flow blockages (including 0% blockage).

Experimental and theoretical investigation on magnetorheological elastomers containing carbonyl iron particles coated with silane coupling agent

Abstract Magnetorheological (MR) elastomer composites, comprising soft silicone rubber, various additives, and different weight fractions of carbonyl iron particles (CIPs) coated with silane coupling agent, are produced via a novel manufacturing process in an anisotropic state. This study encompasses both experimental and modeling investigations into the dynamic viscoelastic properties of MREs in shear mode under varying magnetic fields, displacement amplitudes, and frequencies. Two MRE vibration mitigation devices are fabricated to experimentally assess the shear storage modulus and the loss factor of MREs. The experimental findings reveal a pronounced MR effect in the MRE devices, where both the shear storage modulus and the loss factor increase with rising magnetic fields, frequencies, and particle weight fractions, yet decrease with higher displacement amplitudes. A modified fractional-derivative equivalent parametric model, grounded in a magnetic field- and frequency- dependent shear modulus model along with internal variable theory, is proposed to describe the effects of these key influencing factors on the MREs' dynamic viscoelastic properties. Comparative analysis of experimental and numerical data demonstrates that this refined mathematical model can accurately represent the dynamic viscoelastic properties of MREs.

Experimental investigation of bond behavior with lap splice for CFRP-steel composite bars in coral sea-sand aggregate seawater concrete

The pull-out tests on a total of 81 lap-spliced specimens in 27 groups were conducted to investigate the lap-spliced behavior and the appropriate splice length for CFRP-steel composite bars (C-FSCB) in coral sea-sand aggregate seawater concrete (CSSC). The test variables included the C-FSCB diameter (dc), splice length, concrete cover thickness, concrete strength, lap spacing, stirrup ratio, and materials type. Then, the influence of various test variables on the lap-spliced behavior of C-FSCB in CSSC was analyzed. The results showed that when the splice length was less than 17dc, the specimens exhibited pull-out and concrete splitting failure, while C-FSCB fracture failure occurred when the splice length exceeded 17dc. Severe shear damage was observed on the C-FSCB surface in the case of pull-out and concrete splitting failure. When the splice length was less than 14dc, the bond strength of the specimens was approximately 7.2 MPa. As the splice length increased beyond 14dc, the bond strength gradually decreased. After the cover thickness was greater than 4dc or the compressive strength of CSSC was greater than 30 MPa, the variation in bond strength of the specimens can be negligible. Increasing the stirrup ratio led to an increase in bond strength and a significant reduction in crack width. Compared to specimens with steel bars, the bond strength reduction for specimens with C-FSCB exceeded 25%. Based on the test results, calculation formulas for the bond strength and splice length of C-FSCB in CSSC were established. Furthermore, referring to the approach in the Chinese code GB 50010–2010, a simplified calculation formula for splice length was proposed.

Investigation of Machining Parameters for Turning Process

Manufacturing industries mainly concentrates on how to minimize the cost of the products. The process planers have to prepare the process plan of the product based on the availability of the recourses. All the information is available in the plan including inspection and delivery date of the product. Based on the recommendation of the manufacturing and inspection methods, components are produced at affordable cost. Most of the research work concentrated on selection of machining parameters using optimization techniques and also prove that the machining time / cost were minimized for the particular components / operations. In this work, tool nomenclature is to be considered for the investigation for selection of machining parameters. Work presents an experimental investigation of the influence of the three most important machining parameters of depth of cut, feed rate and spindle speed on surface roughness during turning of aluminium alloy. In this study, the design of experiment which is a powerful tool for experimental design is used to optimize the machining parameters for effective machining of the work piece. L9 orthogonal array experimental design method as well as analysis of variance (ANOVA) is used to analyse the influence of machining parameters on MRR &amp; Machining Time. Two different grade of aluminium alloy i.e. AL 6063 &amp; AL 6068 were machined with input parameters of depth of cut and speed. The output parameters are MRR and machining time. Based on the results empirical equations are formed and optimized results are validation .The optimal results are recommended to manufacturing industries.

Experimental investigation of concrete incorporating recycled concrete aggregates

Experimental investigation of concrete incorporating recycled concrete aggregates

Experimental Investigation of Phase Equilibria in the Al–Mo–Hf Ternary System at 400 °C and 600 °C

This study investigates the phase equilibria of the Al-Mo-Hf ternary system at 400 °C and 600 °C using X-ray diffraction (XRD) and electron probe microanalysis (EPMA/WDS) techniques. Seven three-phase and five two-phase regions were identified at 400 °C, while eight three-phase and four two-phase regions were identified at 600 °C. Despite variations in the solid solubility ranges of certain compounds, the distribution of phase zones in the isothermal cross-section remained consistent at both temperatures. Using the experimental results and logical deductions, isothermal cross-sections were constructed for the Al-Mo-Hf ternary system at 600 °C and 400 °C.

Experimental Study of White Light Interferometry in Mach–Zehnder Interferometers Based on Standard Single Mode Fiber

In this work, we experimentally analyzed and demonstrated the performance of an in-line Mach–Zehnder interferometer in the visible region, with an LED light source. The different waist diameter taper and asymmetric core-offset interferometers proposed used a single-mode fiber (SMF). The visibility achieved was V = 0.14 with an FSR of 23 nm for the taper MZI structure and visibilities of V = 0.3, V = 0.27, and V = 0.34 with FSRs of 23 nm, 17 nm, and 8 nm and separation lengths L of 2.5 cm, 4.0 cm, and 5.0 cm between the core-offset structure, respectively. The experimental investigation of the response to the temperature sensor yielded values from 50 °C to 300 °C; the sensitivity obtained was 3.53 a.u./°C, with R2 of 0.99769 and 1% every 1 °C in the transmission. For a range of 50 °C to 150 °C, 20.3 pm/°C with a R2 of 0.96604 was obtained.