Series Of Tests Research Articles

Synthesis of novel green nanocomposites by considering enhanced oil recovery and asphaltene adsorption effectiveness in calcite and dolomite formations

Asphaltene deposition is known as the main issues in reservoirs, which causes formation damage in reservoir. This research investigated the effects of a newly introduced green nanocomposites, namely eucalyptus/CuO/Fe3O4/xanthan nanocomposites (EC-NCs), on the inhibition of asphaltene precipitation in calcite and dolomite formations. First, at two time steps of 48 and 96 h, asphaltene adsorption on EC-NCs surfaces was examined through scanning electron microscope (SEM) tests in both calcite and formation tests. Moreover, asphaltene adsorption on the surface of EC-NCs was confirmed through isotherm models including Langmuir and Freundlich and the interfacial tension between CO2 and oil. Finally, a series of static and dynamic tests were performed at the highest adsorption pressure points, including 4200, 3950, and 3700 psi, and at the highest adsorption time step, i.e., 96 h, and the effects of asphaltene adsorption were seen on permeability reduction and asphaltene precipitation. EC-NCs exhibited superior efficacy in both asphaltene adsorption and precipitation inhibition. Two separate pressure changes were observed, and the ratios of the interfacial tension slope in the 2nd to the 1st regions [1st: 200–2700 psi, 2nd:2700–4200 psi] were changed from 19.44 % to 25.00 % and 29.74 % in 48 and 96 h, respectively, and this confirms that asphaltene had indeed adhered to the surface of the EC-NCs. Moreover, at 48, and 96 h, the size reductions of particles in SEM for calcite and dolomite were (29.27 %, 56.81 %), and (59.09 %, 62.25 %), respectively, which shows asphaltene adsorption was more efficient in dolomite formation, and in 96 h.

Quantitative Study of Thermal Response of Timber–Concrete Composite Structures Under Traveling Fire Using Energy Equivalence Method

ABSTRACTThe time equivalent method can be used to quantify the fire intensity of a traveling fire into the time of action of the standard fire, which in turn can be used to assess the extent of damage to a structure under a traveling fire. However, an effective time equivalence method for timber structures has not been developed yet. Therefore, this paper proposed an energy‐based time equivalent method, referred to as the “energy equivalence method (EEM)”, for evaluating the fire resistance of timber structures under traveling fire, and validates its effectiveness through a series of fire tests. The results demonstrate that the EEM effectively quantifies the fire intensity endured by glulam under traveling fire as the equivalent exposure time under the standard fire. Furthermore, the EEM was utilized to investigate the damage behavior of a single‐layer Timber‐Concrete Composite (TCC) frame under traveling fire. The results reveal variations in the fire intensity experienced by the structure at different locations under the same traveling fire scenario, with the most severe damage occurring at a position 40% relative to the ignition end. The fire scale determines the non‐uniformity of the fire intensity and the extent of structural damage, as smaller‐scale fires (fire sizes between 10% and 40%) not only result in significant variations in damage levels at different locations but also have a more adverse impact on the structure. In fire safety design, the selection of standard and traveling fire design methods should be based on the fire scale.

Effect of kaolin ratio on wear, water absorption, acidic resistance, and mechanical properties of thermoset composites

Natural fiber reinforced composites are easy to decompose in nature compared to synthetic fiber reinforced composites. However, due to environmental effects, natural fibers cannot maintain their properties for a long time. This situation has led researchers to search for natural but non-degradable materials. Kaolin is one of the most abundant minerals in nature and is an easy material to obtain. This study investigated the use of kaolin as a potential natural additive for polymer composites. In this direction, different proportions by weight of kaolin were added to two different polymer matrices (polyester and polyvinylester) materials. Mechanical tests were performed on the samples, and a series of tests were carried out to understand the acid resistance, wear resistance and water absorption properties of the samples. Also, SEM images of the fracture surface, wear surface, and surface exposed to the acidic solutions were taken and examined. According to test results, kaolin improved compression strength while reducing tensile and flexural strength. However, serious improvements have been achieved by nearly 45% and 115% in the tensile modulus and nearly 84% and 218% in the flexural modulus of polyester and polyvinylester composites, respectively. Also, kaolin improved acid resistance and wear properties and reduced the water absorption rate of the composites.

Leak-Rate Through Carbon Brush Seals: Experimental Tests Versus Predictions From a Porous Medium Approach

Abstract This study presents a detailed comparative analysis between experimental leakage flow rates and numerical predictions for carbon brush seals with long bristles, utilizing a porous medium model approach. A series of tests were carried out on a static rig (without rotor rotation). The experimental setup allows tests under various interference conditions, revealing significant insights into the flow behavior through the brush seal. A numerical model based on the Darcy-Forchheimer equation is developed to interpret the complex flow dynamics within the brush seal, accounting for viscous, compressible and inertial effects. The study evaluates the impact of brush deformation and porosity on flow resistance, leveraging experimental data to refine the numerical model parameters. This investigation not only deepens the understanding of brush seal flow physics but also improves the predictive accuracy of the numerical model in simulating operational conditions.

A Two-Finger Gripper Actuated by Shape Memory Alloy for Applications in Automation Technology with Minimized Installation Space

The increasing demand for innovative grippers and actuators for the automation sector encourages the development of new and innovative functional principles. Intelligent materials are particularly suitable for this purpose based on their high energy density. In this study, a two-finger gripper driven by shape memory alloys (SMA) for use in automation technology is presented. Previous grippers driven by SMA can only be found in the field of micro gripping due to the limited stroke generated by SMA. Based on a methodical product development, a new type of gripper was developed and is presented in this study, which can achieve an opening width comparable to conventional grippers based on transmission mechanisms. Two different variants of the gripper are shown and compared aiming to minimize the installation space and weight of the gripper. In addition to the design presentation, a prototype is built, and the functionality is demonstrated through various test series.

Total Positivity and Accurate Computations Related to q-Abel Polynomials

The attainment of accurate numerical solutions of ill-conditioned linear algebraic problems involving totally positive matrices has been gathering considerable attention among researchers over the last years. In parallel, the interest of q-calculus has been steadily growing in the literature. In this work the q-analogue of the Abel polynomial basis is studied. The total positivity of the matrix of change of basis between monomial and q-Abel bases is characterized, providing its bidiagonal factorization. Moreover, well-known high relative accuracy results of Vandermonde matrices corresponding to increasing positive nodes are extended to the decreasing negative case. This further allows to solve with high relative accuracy several algebraic problems concerning collocation, Wronskian and Gramian matrices of q-Abel polynomials. Finally, a series of numerical tests support the presented theoretical results and illustrate the goodness of the method where standard approaches fail to deliver accurate solutions.

A study of professional practices, attitudes and barriers to blended tube feeding in Australia and New Zealand.

This study investigates the utilisation of blended tube feeding by health professionals in Australia and New Zealand, assessing factors influencing its implementation following the Australasian Society of Parenteral and Enteral Nutrition blended tube feeding consensus statement. A cross-sectional survey was conducted targeting health professionals across Australia and New Zealand. The survey comprised 35-questions including multiple choice, Likert scales and open-ended responses, to gain insights into blended tube feeding practices and perspectives. The effect of the health professional factors on outcomes was explored in pairs with a series of Chi-squared tests. Odds ratios (ORs) were calculated using standard univariate logistic regression. An exploratory content analysis was used to code the open-ended text responses to the survey questions which were then categorised and further synthesised into overarching themes. Out of 89 health professionals who completed the survey, the majority were dietitians, 63% reported managing fewer than five patients using blended tube feeding within their services. Parental request was the leading reason for adoption. Notable barriers included clinician time constraints, resource limitations and a lack of formal guidelines. Some health professionals considered the primary risk associated with blended tube feeding to be poor growth and/or weight loss. Professional development was pivotal in increasing confidence and advocating for blended tube feeding, with significant correlations observed between blended tube feeding training and clinical practice. This study emphasises the essential role of education, resource availability and institutional policy in promoting blended tube feeding practices for health professionals. Findings suggest that focusing on professional development and standardised resources could significantly enhance knowledge, confidence and competence of health professionals in blended tube feeding application. The outcomes point towards the need for a coordinated approach to support evidence-based blended tube feeding practices, aligning with the Australasian Society of Parenteral and Enteral Nutrition blended tube feeding resources and recommendations.

Continuous Biological Ex Situ Methanation of CO2 and H2 in a Novel Inverse Membrane Reactor (IMR)

A promising approach for carbon dioxide (CO2) valorization and storing excess electricity is the biological methanation of hydrogen and carbon dioxide to methane. The primary challenge here is to supply sufficient quantities of dissolved hydrogen. The newly developed Inverse Membrane Reactor (IMR) allows for the spatial separation of the required reactant gases, hydrogen (H2) and carbon dioxide (CO2), and the degassing area for methane (CH4) output through commercially available ultrafiltration membranes, enabling a reactor design as a closed circuit for continuous methane production. In addition, the Inverse Membrane Reactor (IMR) facilitates the utilization of hydraulic pressure to enhance hydrogen (H2) input. One of the process’s advantages is the potential to utilize both carbon dioxide (CO2) from conventional biogas and CO2-rich industrial waste gas streams. An outstanding result from investigating the IMR revealed that, employing the membrane gassing concept, methane concentrations of over 90 vol.% could be consistently achieved through flexible gas input over a one-year test series. Following startup, only three supplemental nutrient additions were required in addition to hydrogen (H2) and carbon dioxide (CO2), which served as energy and carbon sources, respectively. The maximum achieved methane formation rate specific to membrane area was 87.7 LN of methane per m2 of membrane area per day at a product gas composition of 94 vol.% methane, 2 vol.% H2, and 4 vol.% CO2.

Toward a Better Understanding of Reflood Thermal Hydraulics: A Summary of the OECD/NEA RBHT Project

Reflood thermal hydraulics remains a difficult and complex subject, and understanding the physical phenomena that occur during a reflood transient is important to nuclear safety. The Organisation for Economic Co-operation and Development/Nuclear Energy Agency (OECD/NEA) Rod Bundle Heat Transfer (RBHT) project was designed to provide unique experimental data for code assessment and model development. Participants, which came from 21 international organizations, used analysis codes including APROS, ATHLET, CATHARE, CTF, MARS, RELAP5, TRACE, and SPACE to simulate the tests performed in the RBHT facility. The experimental campaign carried out within the OECD/NEA RBHT project produced data for a total of 16 reflood tests conducted in two test series. An “open” test series consisted of 11 experiments, and a “blind” test series consisted of 5 experiments. In the blind tests, only the initial and boundary conditions were provided to participants prior to simulation of those experiments. Reflood rates ranged from 0.5 to 15 cm/s, thus producing data applicable to dispersed flow film boiling and inverted annular flow film boiling. Inlet subcooling ranged from 2.8 to 80 K. Tests with variable reflood rates and oscillatory reflood rates were included in the test matrix. This paper describes the project and presents a summary of major experimental and analytical findings.

Factors influencing static and cyclic behaviour of polymer-grouted sands

ABSTRACT In this study, thorough laboratory research was conducted in order to increase knowledge of the beneficial effect of water-soluble epoxy resin on the monotonic or cyclic triaxial strength of different sands. Seven sand fractions (with different particle sizes, uniformity coefficients and mineralogical compositions) were injected with solutions of epoxy resin and water, at ratios of 3.0, 2.0 and 1.5. To evaluate the influence of chemical treatment on the static strength behaviour of grouted sands, a series of monotonic triaxial tests on dry specimens and isotropically consolidated undrained (CIU) triaxial tests, were conducted on samples cured for 90 days. CIU cyclic triaxial compression tests were also performed, to assess improvements in the cyclic resistance of treated sands. The experiments showed that this resinous grouting resulted in an appreciable increase in cohesion values, particularly for fine sands and well-graded sands, ranging from 0.15 to 0.66 MPa. Despite the fact that friction angle values were reduced, the overall shear strength increased over a wide range of stresses. Moreover, all grouted sands exhibited a substantial improvement in cyclic properties, with failure occurring at significantly elevated stress levels and after enduring a larger number of loading cycles, compared to their untreated counterparts.

Detection of novel pathogenic variants of Fusarium oxysporum f. sp. lactucae in California

AbstractFusarium wilt, caused by the soilborne fungal pathogen Fusarium oxysporum f. sp. lactucae (FOL), is an economically important disease of lettuce (Lactuca sativa) throughout the world. Four pathogenic races of FOL are reported, though only race 1 is known to exist in the United States. Recently, Californian lettuce growers have expressed increasing concern about Fusarium wilt, as some race 1‐resistant cultivars have exhibited susceptibility, and some susceptible cultivars have displayed reduced disease severity. To determine whether such changes in disease patterns are responses to potentially novel variants, we collected infected plants from commercial fields in the Salinas Valley and Santa Maria regions, isolated the fungus, and conducted a series of pathogenicity tests using a set of FOL race differential cultivars over 2 years (2022 and 2023) in controlled conditions. Pathogenicity tests revealed two new FOL variants that elicited novel disease reaction patterns on the set of differential cultivars that have not been previously described. Isolates Fol621 and Fol621s were less aggressive on race 1‐susceptible Banchu Red Fire, designated Variant‐1. Isolate VSP‐0916 incited severe Fusarium wilt on race 1‐resistant Costa Rica No. 4, designated Variant‐2. Moreover, VSP‐0916 exhibited high aggressiveness and the ability to induce disease in other race 1‐resistant cultivars. This study is the first documentation, to our knowledge, of the occurrence of FOL‐inciting Fusarium wilt on race 1‐resistant lettuce in the United States. Our work provides valuable information critical for the development of Fusarium wilt management strategies, including broad‐spectrum resistance breeding efforts against multiple FOL races.

Mechanical, microstructural, and environmental performance of industrial byproducts in peat reinforcement

Peat is widely regarded as one of the most challenging soil types due to its unfavorable engineering characteristics. Traditional methods for addressing peat-related challenges often involve costly and unsustainable approaches such as soil replacement or chemical treatment with cement. This study aims to introduce novel insights into a sustainable solution for peat stabilization by utilizing industrial waste, thereby promoting sustainable development. Palm oil fuel ash (POFA) is a prevalent industrial byproduct generated in Southeast Asian countries, presenting significant disposal challenges. This research evaluates the performance of POFA as a green binder for peat stabilization through a series of mechanical, microstructural, and environmental tests. The findings demonstrate that POFA serves as an environmentally sound and effective binder, substantially improving the engineering properties of peat while also immobilizing toxic elements within the stabilized peat matrix. Consequently, this environmentally friendly and sustainable approach enhances the poor engineering properties of peat.

Printability Metrics and Engineering Response of HDPE/Si3N4 Nanocomposites in MEX Additive Manufacturing.

Herein, silicon nitride (Si3N4) was the selected additive to be examined for its reinforcing properties on high-density polyethylene (HDPE) by exploiting techniques of the popular material extrusion (MEX) 3D printing method. Six different HDPE/Si3N4 composites with filler percentages ranging between 0.0-10.0 wt. %, having a 2.0 step, were produced initially in compounds, then in filaments, and later in the form of specimens, to be examined by a series of tests. Thermal, rheological, mechanical, structural, and morphological analyses were also performed. For comprehensive mechanical characterization, tensile, flexural, microhardness (M-H), and Charpy impacts were included. Scanning electron microscopy (SME) was used for morphological assessments and microcomputed tomography (μ-CT). Raman spectroscopy was conducted, and the elemental composition was assessed using energy-dispersive spectroscopy (EDS). The HDPE/Si3N4 composite with 6.0 wt. % was the one with an enhancing performance higher than the rest of the composites, in the majority of the mechanical metrics (more than 20% in the tensile and flexural experiment), showing a strong potential for Si3N4 as a reinforcement additive in 3D printing. This method can be easily industrialized by further exploiting the MEX 3D printing method.

Can digital technology adoption promote environmental innovation in small and medium-sized enterprises (SMEs)? Evidence from China

Despite the widespread acknowledgment in both industry and academia of the substantial potential of digital technology for fostering innovation and sustainable development, there remains uncertainty surrounding whether integrating these technologies can improve environmental innovation in small and medium-sized enterprises (SMEs) due to the liability of smallness. This paper utilizes a panel dataset comprising 1036 Chinese manufacturing SMEs listed between 2011 and 2020 to investigate the influence of different digital technology adoption strategies—specifically, digital technology adoption breadth (DTAB) and digital technology adoption depth (DTAD)—on SMEs' environmental innovation. Additionally, we examine the moderating effects of government subsidies and industrial agglomeration on these relationships. The results reveal that (1) DTAB has a negative effect on SMEs' environmental innovation; (2) DTAD positively affects SMEs' environmental innovation; and (3) both government R&D subsidies and environmental subsidies can positively moderate the relationships among DTAB, DTAD, and environmental innovation within SMEs. These findings are extended and upheld after undergoing a series of further analyses, endogeneity analyses, and robustness tests. Our research suggests that SMEs are not as suited to the broad adoption of digital technologies as large firms; instead, they should focus on the deep application of specific digital technologies to promote environmental innovation.

Threshold of Saturation Degree of Unsaturated Sand to Cause Liquefaction Considering the Sample Volumetric Strain: Modelization and Experimental Laboratory Investigation

ABSTRACT This paper aims to determine a non-liquefiable domain corresponding to the threshold of saturation degree where liquefaction does not occur under cyclic loading. To determine this threshold, sample volumetric strain at liquefaction state of unsaturated soil was modeled considering the suction. In low saturation degree zones, capillary suction is taken into account. In a high saturation degree zone, spherical suction caused by surface tension of air bubbles is considered by using its microscopic analysis and its equivalent size. Finally, three series of experimental tests have been made to give the data and verify the presented model.

Design of Nanosecond Pulse Laser Diode Array Driver Circuit for LiDAR

The pulse laser emission circuit plays a crucial role as the emission unit of time-of-flight (TOF) LiDAR. This paper proposes a nanosecond-level pulse laser diode array drive circuit for LiDAR, primarily aimed at addressing the issue of high-speed scanning drive for the laser diode array at the emission end of solid-state LiDAR. Based on the single pulse laser diode drive circuit, this paper innovatively designs a circuit that includes modules such as a boost circuit, linear power supply, high-speed gate driver, GaN field-effect transistor, and pulse narrowing circuit, realizing an 8-channel laser diode array drive circuit. This circuit can achieve a pulse laser array drive with a single channel operating frequency of greater than 100 kHz, an output pulse width of less than 5 ns, a peak power greater than 75 W, and a channel switching time that does not exceed 1 μs. A field programmable gate array (FPGA) is used to control the operation of this circuit and perform a series of performance tests. Experimental results show that this circuit has a high repetition rate, large output power, a narrow pulse width, and fast switching speeds, making it highly suitable for use in the optical emission module of solid-state LiDAR.

Bone-targeted ultrasound-responsive nanobubbles for siRNA delivery to treat osteoporosis in mice

This project aimed to study the efficacy of a bone-targeted ultrasound-responsive nanobubble (NB) platform to deliver gene-silencing cathepsin K (CTSK) siRNA into the bone for osteoporosis treatment using in vitro and in vivo studies. To this end, characterization of CTSK siRNA loaded NB functionalized with alendronate (NB-CTSK siRNA-AL) was performed using transmission electron microscopy (TEM) imaging, and a release profile was obtained through fluorescent spectroscopy. In vitro studies were conducted by culturing NB-CTSK siRNA-AL with osteoclasts to evaluate siRNA uptake, CTSK expression, and the expression of tartrate-resistant acid phosphatase (TRAP). A control group and an NB-CTSK siRNA-AL treated group of ovariectomized (OVX) mice (n = 4) were tested. The OVX group that received treatment underwent weekly sessions for 4 weeks, during which they were exposed to low-intensity pulsed ultrasound (LIPUS) stimulation following administration of NB-CTSK siRNA-AL, prior to being sacrificed. Both groups underwent a series of tests to evaluate the bone targeting, safety, and efficacy of the nanoplatform. These tests included biodistribution studies conducted at 4 h and 24 h post-injection, a 3-point bending test of the femurs, nano-computed tomography analysis, as well as Hematoxylin & Eosin histological staining, Masson's Trichrome staining, and CTSK staining. The biodistribution showed the accumulation of NB-CTSK siRNA-AL in the bone and liver. Results showed that the OVX mice treated with NB-CTSK siRNA-AL had increased distal cortical bone thickness (174.4 ± 5.28 μm vs. 144.3 ± 10.66 μm, p > 0.05)) and bone volume fraction (16.5 ± 3.96 % vs. 6.55 ± 0.13 % (p > 0.05)). A reduced collagen degradation and downregulated CTSK expression were evident in the staining procedures. No adverse effects were recorded within histological assessments on the liver, kidney, and heart post-treatment. Morphology was shown to be normal and healthy within muscle cells post-LIPUS stimulation of NB-CTSK siRNA-AL. From these results, it can be concluded that an ultrasound-mediated NB-CTSK siRNA-AL can serve as a reliable, safe CTSK siRNA carrier to bone-specific targets for in vivo osteoporosis treatment.

Dynamic Inversion-Enhanced U-Control of Quadrotor Trajectory Tracking

This study proposes a universal (U)-control enhanced with dynamic inversion for a class of multiple-input multiple-output (MIMO) quadrotor flight tracking operations. In the technique, a robust compensator is integrated with the U-controller to achieve stabilisation at the equilibrium and setpoint tracking in the presence of any unmodelled uncertainties and external disturbances. A series of bench tests of simulated and real experiments on a Parrot Mambo quadrotor are conducted to show the design framework from the academic formulation to Simulink simulation and real flight tests.

An evaluation of square footing response on lime-treated geotextile-reinforced silty sand: contrasting experimental and computational approaches

Improving soil strength and reducing the anticipated settlement and construction cost is a great paradox for civil as well as geotechnical engineers. In this paper, these aspects and other suitable types of ground improvement are discussed based on the principles of using geosynthetics for soil reinforcement. A series of load-settlement tests were also performed to compare strength and settlement of the silty sand reinforced with lime and one layer of geotextile. The study finds the maximum insertions of geotextile at 0.2D (3.0 cm) beneath the square footing base, and the lime percentage of 5.0% increases the UBC substantially. The UBC of lime-treated and geotextile-reinforced silty sand was to an optimum of 1,360 kN/m2 that has shown an enhancement of 258% compared to that of untreated and unreinforced silty sand that is approximately 380 kN/m2. Furthermore, comparative analysis between two ANN models was performed to provide improved estimate of the UBC, namely artificial neural network (ANN) and extreme learning machine (ELM). The developed computational models were then compared with experiment data, which proved that such models are more economical and effective than the expensive and time consuming conventional techniques. Consequently, based on the results, it was further validated that ELM possesses better generalization capability compared to ANN for predictive efficiency and thereby proves the efficiency of the model in estimating the ultimate bearing capacity of square footings incorporated with geotextile and lime-treated silty sand. This places the ELM model as a useful tool in the initial conceptual as well as the design for improvement steps of soil reinforcement.

Design and vibration test of first mirror mount assembly for ITER divertor VUV spectrometer

The divertor vacuum ultraviolet (VUV) spectrometer is a diagnostic system in the ITER tokamak, monitoring impurity content and behavior in the divertor region. The first mirror of the spectrometer, made of silicon carbide (SiC), is exposed to harsh environmental conditions, including high temperatures and significant inertial loads from electromagnetic disruption events. To ensure its reliable performance, we have designed and tested a robust mirror holder assembly. This paper introduces a novel design of the first mirror holder assembly for the ITER divertor VUV spectrometer and presents the results from comprehensive vibration tests conducted on a full-scale mock-up. The design features a double-holder structure with spring plate assemblies to accommodate thermal expansion and resist vibrational loads. The mock-up underwent a series of resonance search, sine dwell, and random vibration tests, replicating the expected loads during vertical displacement events in ITER. The mirror holder assembly and the dummy mirror successfully withstood the vibration tests without damage, validating the design for the ITER environment. The results demonstrate the robustness and reliability of the mirror holder assembly, ensuring the accurate and reliable operation of the divertor VUV spectrometer in ITER.