Experimental Research Articles

Experimental study on the deformation and failure characteristics of cement stone under true triaxial stress state

The cement stone is widely utilized to fill the gap between the formation and the casing in wells. A clear understanding of the deformation and failure mode of cement stone under true triaxial stress state is necessary to ensure the safety and stability of wells. To analyze the three-dimensional deformation and failure characteristics of cement stone, the loading paths with constant Lode angle were employed in conducting true triaxial tests on cement stone. The stress-strain curve and failure mode of cement stone are first analyzed. Then, the three-dimensional deformation characteristics are discussed in meridian and deviatoric planes. Both peak strength and deformability increase with minimum principal stress, but show a tendency to increase and then decrease with intermediate principal stress coefficient. With the increase of minimum principal stress and intermediate principal stress coefficient, the failure mode of cement stone transforms from brittle to ductile behavior. Under elastic stage, the strain path in the meridian plane is a straight line, and is under constant Lode angle within the deviatoric plane. Due to the existence of plastic strain, the strain path in the meridian plane displays a downward convex shape. The strain path in the deviatoric plane deviates from the reference of constant Lode angle for stress, directly reflecting the Lode angle dependence of deformation. Both deformation and failure characteristics of cement stone are dominated by the three-dimensional stress state. Besides, deformation of cement stone is closely related to the failure characteristics of cement stone.

Non-Invasive Assessment of Coronary Microvascular Dysfunction Using Vascular Deformation-Based Flow Estimation.

Non-invasive computation of the index of microcirculatory resistance from coronary computed tomography angiography (CTA), referred to as IMR[Formula: see text], is a promising approach for quantitative assessment of coronary microvascular dysfunction (CMD). However, the computation of IMR[Formula: see text] remains an important unresolved problem due to its high requirement for the accuracy of coronary blood flow. Existing CTA-based methods for estimating coronary blood flow rely on physiological assumption models to indirectly identify, which leads to inadequate personalization of total and vessel-specific flow. To overcome this challenge, we propose a vascular deformation-based flow estimation (VDFE) model to directly estimate coronary blood flow for reliable IMR[Formula: see text] computation. Specifically, we extract the vascular deformation of each vascular segment from multi-phase CTA. The concept of inverse problem solving is applied to implicitly derive coronary blood flow based on the physical constraint relationship between blood flow and vascular deformation. The vascular deformation constraints imposed on each segment within the vascular structure ensure sufficient individualization of coronary blood flow. Experimental studies on 106 vessels collected from 89 subjects demonstrate the validity of our VDFE, achieving an IMR[Formula: see text] accuracy of 82.08 %. The coronary blood flow estimated by VDFE has better reliability than the other four existing methods. Our proposed VDFE is an effective approach to non-invasively compute IMR[Formula: see text] with excellent diagnostic performance. The VDFE has the potential to serve as a safe, effective, and cost-effective clinical tool for guiding CMD clinical treatment and assessing prognosis.

Passive Blowing Strategy to Enhance Aerodynamic Performance and Noise of a Hollow-bladed Axial Fan: An Experimental Study

Passive Blowing Strategy to Enhance Aerodynamic Performance and Noise of a Hollow-bladed Axial Fan: An Experimental Study

Experimental Study on Early-Age Cracking Behavior of Hooked-End Steel Fiber–Reinforced Concrete under Different Curing Temperatures

Experimental Study on Early-Age Cracking Behavior of Hooked-End Steel Fiber–Reinforced Concrete under Different Curing Temperatures

Ultrasound-guided minimally invasive cubital tunnel thread release: An experimental study.

Cubital Tunnel Syndrome is characterized by the compression of the ulnar nerve in the cubital tunnel and can cause restrictions to the activities of daily living. Traditional treatment includes conservative methods and, in more severe cases, different types of surgery. In these cases, common side effects of surgery may limit the clinical success. A new alternative could be a minimally invasive Ultrasound-guided (US-guided) thread release of cubital tunnel retinaculum also known as the Osborne's ligament. The aim of this study was to assess the efficacy and safety of ultrasound-guided thread cubital tunnel release (TCuTR) in an anatomical specimen model. In this single-center prospective experimental study, US-guided thread cubital tunnel release (TCuTR) was performed on 11 softly embalmed anatomic specimens. Subsequently, the elbows were dissected to assess the transection of Osborne's ligament and potential damage to adjacent structures. Due to calcification, one specimen was ineligible for the intervention. In all remaining ten interventions, Osborne's ligament (OL) was completely transected, without any damage to the surrounding nerves, blood vessels, tendons, or muscles. US-guided decompression has demonstrated a high success rate in transecting Osborne's ligament while averting damage to neighboring structures. This emerging technique appears to present an efficient and secure alternative to existing procedures.

Experimental study on reliable combustion of a 15-kw sofc exhaust gas burner across a wide range of operating conditions

Experimental study on reliable combustion of a 15-kw sofc exhaust gas burner across a wide range of operating conditions

Experimental study and techno-economic evaluation of an active fault detection kit in the prospect of future zero energy building installations

This article presents an active fault detection kit, applicable to low voltage single-phase electrical installations, in the prospect of the Zero Energy Building concept, integrating on-site renewable energy generation and energy storage. This simple, flexible, self-powered and compact kit is capable of detecting faults, such as power theft (meter tampering), unintentional islanding and neutral conductor loss. Its operation is based on harmonic voltage injection, in series with the electrical installation, through a low-power H-bridge inverter and a current transformer, along with the corresponding harmonic current measurement, to estimate the impedance and effectively detect faulty conditions; the fast and robust Goertzel algorithm is utilized. Moreover, it features IoT communication capabilities, employing the ESP32 microcontroller, to exchange data and information with the installation meters. The functionality and effective fault detection of the proposed device are validated, through experimental tests on a custom-developed hardware prototype; IoT connectivity and data uploading are experimentally tested and verified, too. Finally, a sustainability assessment study is performed, using the Life Cycle Cost Analysis tool.

Bond–Slip Behavior of Concrete Pile–Cemented Soil Interface Considering Thermal–Temporal Effect: Experimental Study and Constitutive Modeling Based on Disturbed State Concept

Bond–Slip Behavior of Concrete Pile–Cemented Soil Interface Considering Thermal–Temporal Effect: Experimental Study and Constitutive Modeling Based on Disturbed State Concept

Experimental study on inhibiting methane-coal dust explosion by APP-diatomite composite explosion suppressant in the pipe network

To prevent and control the methane/coal dust compound explosion disaster, the APP-diatomite composite powder inhibition of methane/coal dust compound explosion experiments were carried out in the self-constructed pipe network. The composite powder was characterized by scanning electron microscopy and X-ray photoelectron spectroscopy. The change rules of methane/coal dust composite explosion pressure and flame propagation velocity were analyzed using different compounding ratios of powders in several monitoring points. The results show that the composite powder exhibited irregular morphology and the APP powder is uniformly distributed on the diatomite porous mesh structure. When the APP loading on the surface of diatomite is 40 wt%, composite powder has the best effect on explosion suppression, with the peak maximum explosion overpressure and the peak maximum flame propagation velocity reduced by 71.5% and 92.2%, respectively. The explosion suppression mechanism is revealed through pyrolysis properties, explosion products, and chain reaction.

Conceptual Change and Developing Mental Motivation in Physics: Effects of Transformational Learning Theory

This study to investigate the effect of using transformative learning theory (TLT) -based teaching model on a conceptual change and developing mental motivation in Physics for secondary school students. The study follows the descriptive, analytical, and experimental method with a quasi-experimental design for experimental and control groups. sample consisted of (70) students from 1st-grade secondary school who are divided into two groups: the experimental group (34) students and the control group (36) students. To achieve the objectives of the study, A Conceptual Change Test (CCT) and A Mental Motivation Scale (MMS) were constructed. The results revealed that a TLT-based teaching model has effects on changing concepts and developing mental motivation in Physics. Moreover, there is a statistically significant correlation (r= 0.358) between the growth of mental motivation and the inducing of a conceptual change in physics for secondary school students. In light of the results, the study recommended conducting further studies on transformational learning theory (TLT) and conceptual change and mental motivation in various fields and learning stages.

Mechanical Behavior of BFRP Cable Rock Bolts: Experimental and Analytical Study

Mechanical Behavior of BFRP Cable Rock Bolts: Experimental and Analytical Study

The therapeutic effects of mesenchymal stem cells and their secretome on oral squamous cell carcinoma.

Oral cancers are prevalent in the human population, particularly in unindustrialized countries. In 90 % of oral cancers, the tumors arise from squamous cells, which is called oral squamous cell carcinoma (OSCC). Despite new treatment strategies, the morbidity and mortality rates are still high. Current treatment options including surgery, chemotherapy, and radiotherapy are not effective in the treatment of the tumor. Cell therapy with mesenchymal stem cells (MSCs) is considered one of the leading strategies in cancer treatment. However, the field of MSC therapy in OSCC is immature and ongoing studies are being conducted in experimental and pre-clinical studies. Here, we reviewed these studies to figure out whether the use of MSCs could be worthwhile in OSCC therapy or not. Both native and engineered MSCs as well as their secretome have been used in the treatment of OSCC. It seems that genetically modified MSCs or their secretome could inhibit the tumorigenesis of OSCC. However, further pre-clinical studies are required to come to a conclusion.

Go with your gut! The beneficial mood effects of intuitive decisions.

People make countless decisions every day. We explored the self-regulatory function of decisions and assumed that the very act of making a decision in everyday life enhances people's mood. We expected that this decision-related mood change would be more pronounced for intuitive decisions than for analytical ones. The ease of making a decision and the feeling of rightness were expected to mediate the effect of intuitive (vs. analytical) decisions on participants' mood. In a preregistered experimental experience sampling study, participants from the general population were asked to report when they were about to make an everyday decision over the course of 14 days (N = 256 participants, 6,779 decisions). For each decision, participants were randomly instructed to decide either based on their intuition or based on careful analysis. We assessed several variables before and immediately after the decision. Participants also reported retrospectively on their choices in voluntary follow-up assessments. Making a decision per se immediately enhanced participants' mood. This mood enhancement was stronger for intuitive compared to analytic decisions and persisted until follow-up. Ease of decision, but not feeling of rightness, mediated this effect. Intuitive decisions compared to analytic decisions were more likely to be implemented and led to greater satisfaction and pleasantness of the chosen option. Having more options for a particular decision led to generally higher mood improvement and satisfaction. This is the first empirical demonstration showing that using one's gut has beneficial effects in everyday life. Study limitations and implications for theory and practice are discussed. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Experimental and Numerical Study on the Seismic Performance of Self-Centering Isolated Piers

Experimental and Numerical Study on the Seismic Performance of Self-Centering Isolated Piers

Ammonia Sprays for Combustion: A Review

Ammonia is a globally transported chemical used for a variety of applications, most notably, the production of fertiliser. Over the past decade, attention has been afforded to the use of ammonia as an energy carrier, coupling global supply of renewable energy to demand regions. Ammonia’s advantages as an energy carrier include its ease of liquefaction and established international transportation routes; overcoming its low reactivity, excessive production of nitrogen oxides and its toxicity remain as challenges. For energy applications, fuel delivery is a critical aspect of effective combustion in boilers, burners and engines. Due to its adaptable phase change characteristics, ammonia fuel may be injected as a liquid or vapour, each with respective advantages or disadvantages. The focus of this review concerns the characterisation of liquid ammonia fuel injection for combustion, including recent research findings from experimental and simulation studies. Liquid ammonia injection can result in the highly dynamic so-called ‘flashing’ or ‘flash boiling’ phenomena. Research findings have been drawn from other related applications such as accidental hazardous releases. Bespoke optical experimental rigs together with diagnostic techniques and two-phase computational fluid dynamics (CFD) simulations have enabled studies of the flashing jets under various initial or final conditions, with recent work also examining ammonia spray combustion. The review concludes with an insight into future trends and requirements for liquid ammonia combustion. Reciprocating engines for marine propulsion are cited as potential early adopters of ammonia energy.

Flexural Behavior of GFRP–Aluminum Space Truss Strengthened with Prestressed CFRP Tendons: Experimental and Theoretical Study

Flexural Behavior of GFRP–Aluminum Space Truss Strengthened with Prestressed CFRP Tendons: Experimental and Theoretical Study

Nuclear Structure and Decay Data for A=230

The experimental reaction and decay studies producing nuclei in the A=230 mass chain have been reviewed. Data on elements from radon (Z=86) to americium (Z=95) are included, and level and decay schemes are presented for these nuclides. This work supersedes the previous evaluation for this mass chain (2012Br12).

Supercritical carbon dioxide chelation extraction of heavy metal ions from drilling fluid waste: Experiment and simulation

This study evaluates the application of supercritical carbon dioxide chelation extraction technology for treating heavy metal ions (Zn2+ and Cr3+) in drilling fluid waste. Through a combination of experimental and molecular dynamics simulation methods, the influence of extraction parameters (temperature, pressure, duration, and chelating agents) on the extraction efficiency are investigated. Findings show that increased duration and pressure significantly improve extraction efficiency, while temperature has a complex effect, initially increasing efficiency but plateauing and slightly decreasing at higher temperatures. The optimum extraction condition with pressure of 220 bar, temperature 348.15 K and an extraction duration of 70 min using ethylene diamine tetraacetic acid (EDTA) as the chelating agent has been determined. Importantly, molecular simulation analysis revealed that citric acid outperforms EDTA in terms of Zn2+ and Cr3+ aggregation by forming larger aggregates with greater numbers of molecules while reducing overall aggregate count. Furthermore, optimization of extraction pressure in the EDTA system shows potential benefits. These results suggest that supercritical carbon dioxide chelation extraction technology has strong potential for environmentally friendly and reliable waste management in the drilling industry. This study represents a significant step forward in developing sustainable solutions for heavy metal removal from drilling fluid waste.

Effect of Adsorption of Two Green Biopolymers on the Corrosion of Aluminum in 1.0 M NaCl Solution: Physicochemical, Spectroscopic, Surface and Quantum Chemical Exploration

Although aluminum is an extremely versatile material and can be manufactured and used for a wide range of industrial purposes, it has a limited resistance to corrosion. Hence, the efficacy of two linear biopolymers, keratan (Ker) and chitosan (Chi), was explored, for the first time, as ecologically safe metallic corrosion inhibitors (CIs) for Al in 1.0M NaCl solution at different temperatures. For performing this study, several experimental and theoretical methods were applied. By combining these methods, it was confirmed that the investigated biopolymers were set to be effective inhibitors for Al corrosion in 1.0M NaCl solution. Using a 500mg/L dose of CIs, inhibition efficiencies (% IEs) of 92.7% and 86.4% were achieved for Ker and Chi, respectively, indicating their strong adsorption on the metal surface. Thermodynamic and kinetic investigations signified that the adsorption was founed to be physical and obeyed the Langmuir isotherm. The kinetics and mechanism of Al corrosion as well as its inhibition by the tested biopolymers were inspected. The results demonstrated that these biopolymers behaved as mixed-type and interface-type inhibitors. To investigate the inhibition mechanism, theoretical quantum chemical methods were also applied. The experimental investigations were validated by theoretical computations.

Emerging Phytochemicals to Treat Leishmaniasis: A Review of Experimental Studies from 2011 to 2021

: Leishmaniasis is a protozoan disease caused by a parasite from the genus Leishmania. It is known as a neglected tropical disease by WHO and is the second-leading cause of death by parasites after malaria. Chemotherapy is the only effective way to control the disease, but treatment options for leishmaniasis are limited. The majority of the drugs are costly, have serious side effects and necessitate hospitalisation. The lack of an effective vaccine, in addition to the emergence of resistance to currently available drugs, has all been raised as major concerns, especially in endemic areas of developing countries. Phytochemicals might contribute to the development of novel and effective drugs for the treatment of leishmaniasis by providing selectively targeted intervention in parasites. Many phytochemicals (quinones, alkaloids, terpenes, saponins, phenolics) and their derivatives are quite active against diverse groups of pathogens, such as viruses, bacteria, fungi and parasites. To date, many phytochemicals have shown potent anti-leishmanial activity with highly selective mode of action. However, due to a lack of interaction between academician and pharma industries none of them has undergone the clinical assessment. The present review will analyse the most promising phytochemicals and their synthetic compounds, which have shown antileishmal activity in in-vitro and subsequently in animal studies from 2011-2021. These phytochemicals are apigenin, hydroxyflavanone, Epigallocatechin-O-3 gallate, caffeic acid, α-bisabolol, β-caryophyllene, ursolic acid, quinones, which have shown notable anti-leishmanial activities in several independent studies.