Self-designed Apparatus Research Articles

Effects of Temperature, Ionic Strength and Humic Acid on the Transport of Graphene Oxide Nanoparticles in Geosynthetic Clay Liner.

With the wide application of graphene oxide nanoparticles (GONPs), a great amount of GONP waste is discarded and concentrated in landfills. It has been proven that GONPs have strong toxicity and could gather toxic substances due to their high adsorption capacity. GONPs will seriously pollute the surrounding environment if they leak through the geosynthetic clay liner (GCL) in landfills. To investigate various factors (temperature, ionic strength (IS) and humic acid (HA)) on the transport and retention of GONPs in the GCL, a self-designed apparatus was created and column tests were carried out. The experimental results show that GONPs could be transported through the GCL. The mobility and sorption ratio of GONPs in GCL decreased with an increase in temperature and IS, and increased with an increase in HA. The temperature had little effect on the deposition ratio of GONPs in the GCL. The deposition ratio of GONPs in the GCL increased with IS, and decreased with an increase in HA. The transport of GONPs in GCL, glass beads and quartz sand was compared, and the results show that the retention ability of the GCL is much better than other porous materials. The experimental results could provide significant references for the pollution treatment in landfills.

Experimental study on freezing point of deep clay under high external load conditions

A rational evaluation of freezing point of deep clay under high pressure is required for artificial freezing construction of deep mining works. The freezing point of deep clay under high external load was measured via a self-designed apparatus with soil temperature monitored by high-precision temperature transducer and external load applied by servo-hydraulic system. The feasibility of the apparatus was verified by comparing the test result to that of the common cooling curve method under no external load. Cooling curves for deep clay sampled from a coal mine at 510–515 m were acquired at six load levels (0.0, 2.0, 4.0, 6.0, 8.0 and 10.0 MPa) and four water contents (25.0%, 30.0%, 34.0% and 38.0%). Results show that the greater the water content, the more pronounced the equilibrium freezing stage. In the absence of external load, equilibrium freezing was observed, whereas temperature jump becomes more noticeable with increasing load. Freezing point and initial nucleation temperature both rise with greater water content, while depress approximately linearly with higher load. A simple model for evaluating the freezing point of deep clay was developed based on the Mizoguchi model, incorporating both matric and pressure potential. The results will provide theoretical evidence for determining the thickness and location of frozen wall during artificial freezing construction in deep strata.

Electromechanical degradation of REBCO coated conductor tapes under combined tension and torsion loading

In this study, the electromechanical and critical current degradation behaviors of rare earth–barium–copper–oxide (REBCO) coated conductors (CCs) under uniaxial tension, torsion, and tension–torsion deformations were experimentally and theoretically investigated. A self-designed apparatus was established to provide a 77 K cooling environment incorporated with a mechanical loading fixture to determine the critical current (Ic) under different deformation modes. The effects of the deformation and mechanical properties of REBCO CCs on the Ic and its degradation were addressed. Uniaxial tensile tests demonstrated that the irreversible Ic degradation was mainly related to the plastic failure of the conductor. A comparative analysis of the electromechanical behavior of the three deformation modes indicated that the longitudinal strain in the REBCO superconducting film was responsible for Ic degradation, unifying the characterization of different deformation modes. Furthermore, the degradation modeling of the strain dependence of Ic based on the Ekin power-law formula and Weibull distribution function was extended to examine the influence of different deformation modes. The phenomenological model can predict Ic degradation behavior effectively, including reversible and irreversible processes in the combined tension–torsion deformation mode.

Enhanced Biomechanically Mediated "Phagocytosis" in Detached Tumor Cells.

Uptake of particles by cells involves various natural mechanisms that are essential for their biological functions. The same mechanisms are used in the engulfment of synthetic colloidal drug carriers, while the extent of the uptake affects the biological performance and selectivity. Thus far, little is known regarding the effect of external biomechanical stimuli on the capacity of the cells to uptake nano and micro carriers. This is relevant for anchorage-dependent cells that have detached from surfaces or for cells that travel in the body such as tumor cells, immune cells and various circulating stem cells. In this study, we hypothesize that cellular deformability is a crucial physical effector for the successful execution of the phagocytosis-like uptake in cancer cells. To test this assumption, we develop a well-controlled tunable method to compare the uptake of inert particles by cancer cells in adherent and non-adherent conditions. We introduce a self-designed 3D-printed apparatus, which enables constant stirring while facilitating a floating environment for cell incubation. We reveal a mechanically mediated phagocytosis-like behavior in various cancer cells, that was dramatically enhance in the detached cell state. Our findings emphasize the importance of including proper biomechanical cues to reliably mimic certain physiological scenarios. Beyond that, we offer a cost-effective accessible research tool to study mixed cultures for both adherent and non-adherent cells.

Apparatus for testing He leakage through flange gaskets at elevated pressure and temperature

The study focuses on the measurement of He leakage from the cooling circuits of the helium-cooled GFR (gas-cooled fast reactor). It is necessary to measure two phenomena, namely losses of He from the pipeline circuit through flange joints and the contamination of helium inside the pipeline by the diffusion of permanent gases from the external environment (i.e. against the pressure gradient). Methods for determining the tightness of flange joints according to current standards are not fully suitable for these purposes. For this reason, a self-designed apparatus was constructed in order to measure both effects at pressures up to 20 MPa and temperatures within the range from ambient values up to 400 °C. Gas chromatography with a PDHID detector was used to determine the rate of diffusion of nitrogen and other permanent gases through the flange into pure He. On the other hand, the He leakage through the piping flange joint into the external environment was measured using a gas chromatograph with a high sensitivity TCD. The issues of heat distribution within the high-pressure measuring vessel are discussed as well.

Photocatalytic Pretreatment of Commercial Lignin Using TiO2-ZnO Nanocomposite-Derived Advanced Oxidation Processes for Methane Production Synergy in Lab Scale Continuous Reactors

The photocatalytic pretreatment of lignocellulosic biomass to oxidize lignin and increase biomass stability has gained attention during the last few years. Conventional pretreatment methods are limited by the fact that they are expensive, non-renewable and contaminate the anaerobic digestate later on. The present study was focused to develop a metal-derived photocatalyst that can work with visible electromagnetic spectra light and oxidize commercial lignin liquor. During this project the advanced photocatalytic oxidation of lignin was achieved by using a quartz cube tungsten T3 Halogen 100 W lamp with a laboratory manufactured TiO2-ZnO nanoparticle (nanocomposite) in a self-designed apparatus. The products of lignin oxidation were confirmed to be vanillic acid (9.71 ± 0.23 mg/L), ferrulic acid (7.34 ± 0.16 mg/L), benzoic acid (6.12 ± 0.17 mg/L) and p-coumaric acid (3.80 ± 0.13 mg/L). These all products corresponded to 85% of the lignin oxidation products that were detectable, which is significantly more than any previously reported lignin pretreatment with even more intensity. Furthermore, all the pretreatment samples were supplemented in the form of feedstock diluent in uniformly operating continuously stirred tank reactors (CSTRs). The results of pretreatment revealed 85% lignin oxidation and later on these products did not hinder the CSTR performance at any stage. Moreover, the synergistic effects of pretreated lignin diluent were seen that resulted in 39% significant increase in the methane yield of the CSTR with constant operation. Finally, the visible light and nanoparticles alone could not pretreat lignin and when used as diluent, halted and reduced the methane yield by 37% during 4th HRT.

Synthesis and Modification of Polyurethane Foam Doped with Multi-walled Carbon Nanotubes for Cleaning up Spilled Oil from Water

Marine oil spills have raised widespread environmental concerns. Adsorbents with high oil absorption efficiency and reusability are highly desirable. This paper demonstrates a technical route for the manufacture of polyurethane-based adsorbents, aiming at developing robust and efficient materials for treating oil-contaminated water or remedying emergency oil spill accidents. The investigation includes the synthesis of polyurethanes modified with multi-walled carbon nanotubes, the characterizations of their properties, and the analysis of the capacity and feasibility of their applications in oil–water separation. The compositions of the products were characterized by FTIR, XPS, and Raman spectroscopy; the morphologies were analyzed by SEM; the hydrophobicities were tested by the water contact angle, and the thermal properties by TGA; the mechanical properties were depicted by Young’s modulus and the tensile-strain response performance; and the measurements of the absorption capacities and their performance in applications for oils-water separation were conducted in a self-designed apparatus and determined by gravimetric analysis. The results indicate that the developed adsorbents are superhydrophobic and highly robust with a water contact angle of 159°, tensile strain 27% higher and compressive strain 35% lower than regular polyurethanes, absorption capacity up to 60 g g−1, and reusability of 900 absorption–desorption cycles. The high oil absorption efficiency, capacity, and reusability of the adsorbents were confirmed by various oil/organics-water systems, such as engine oil-, silicone oil-, chloroform-, hexane-, toluene-, and kerosene-water system. It is concluded that the adsorbents are efficient not only for floating oils/organics-water but also for well dispersed or mixed oils/organics-water systems; and they can be operated in not only a batch mode for high absorption–desorption cycles but also in a continuous mode for a long operational period, which exhibits great potential and is of particular interest for the adsorbents to be used in large scale oil/organics spill cleanups.

Dynamic Experimental Study on the Paraffin Deposition Prevention Performance of Tungsten Alloy Coating Pipe in Simulating Vertical Wellbore.

In this study, a self-designed apparatus was used to provide a quantitative evaluation of the wax prevention effect of tungsten alloy-coated tubing compared with ordinary tubing in oil production. The paraffin deposition of both pipes at different temperatures and different flow rates was studied. The efficiency of paraffin deposition prevention of the tungsten alloy coating pipe was analyzed. The results show that using this apparatus can efficiently and accurately calculate the wax prevention rate and can accurately obtain the wax deposit and wax thickness of the inner wall. The paraffin deposition of both pipes reaches the highest point at 290.15 K, and it reduces with the increase of flow rate. The use of the tungsten alloy coating pipe results in about 30% reduction in paraffin deposition. It provides a promising method for the paraffin inhibition to extend the wax removal cycle.

The measurement of helium leakages through flange gaskets for gas-cooled fast reactors

The study deals with the development of a method that would reliably determine the tightness of flange joints of the helium circuit of a gas-cooled fast reactor (GFR). The proposed procedure and equipment enable the parallel measurement of the helium leakage from a high-pressure cell and He contamination in the cell by the diffusion of gases from the ambient atmosphere against the pressure gradient. The self-designed apparatus is constructed for the performance of long-term tests of both parameters (i.e. both He leakage and its contamination) at a temperature of 400 °C and a pressure of 20 MPa. Nevertheless, the construction limits of the device at which the measurement can be safely carried out are 450 °C/35 MPa. The permanent gases diffusing into helium through the gasket were analyzed by a gas chromatograph with a PDHID detector, whereas the He leakage was determined using a high-sensitivity TCD. The article presents continuous results of tests carried out at ambient temperature. The procedures for data measurement and evaluation are demonstrated on one selected type of gasket with the inner diameter of 44 mm, the outer diameter of 79 mm and the thickness of 14.2 mm.

Dynamics of Biochar-Silty Clay Interaction Using In-House Fabricated Cyclic Loading Apparatus: A Case Study of Coastal Clay and Novel Peach Biochar from the Qingdao Region of China

Biochar has been recently investigated as an eco-friendly material in bio-engineered slopes/landfill covers. A majority of recent studies have focused on analyzing water retention behavior while very few have examined dynamic behavior (i.e., cyclic loading due to earthquake, wind, or wave) of biochar amended soil. As far as the authors are aware, there is no study on the dynamic behavior of biochar amended soils. Considering the above mentioned study as a major objective, field excavated soil was collected and mixed with in-house produced biochar from peach endocarps, at three amendment rates (5%, 10%, and 15%). The un-amended bare soil and biochar amended soil were imposed to a cyclic load in a self-designed apparatus and the corresponding stress-strain parameters were measured. Dynamic parameters such as shear modulus and damping ratio were computed and the results were compared between bare and biochar amended soil. Furthermore, the residual cyclic strength of each soil types were correlated with an estimated void ratio to understand the interrelation between dynamic loading responses and biochar amended soils. The major outcomes of this study show that the addition of biochar decreases the void ratio, thereby increasing the shear modulus and residual cyclic strength. However, the modulus and strength values attenuates after 15 cycles due to an increase in pore water pressure. In contrary, at higher amendment rates, Biochar Amended Soils (BAS) forms clay-carbon complex and decreases both shear modulus and residual cyclic strength.

Experimental study of non-linear fluid flow though rough fracture based on fractal theory and 3D printing technique

In this note, the non-linear fluid flow through rough fracture is investigated experimentally. The rough surface of fracture is generated synthetically based on the fractal dimension (D) and standard deviation (σ). 3D printing technique is used to produce the fracture specimen, in which, different components of the specimen are printed and assembled so that the fracture roughness and aperture can be easily controlled. After that, the self-designed apparatus is used to conduct the fluid flow test on the fractured specimens under various pressure gradients. It is found that, the surface roughness imposes an important impact on the nonlinear characteristics of fluid flow through fracture; and the root-mean-square of the first derivative of profile, Z2, is found effective in characterizing the fracture roughness. Based on the test results and the derived parameters in Forchheimer equation, an empirical equation is proposed to relate the hydraulic aperture (eh) to Z2 and mechanical aperture (em). Furthermore, the correlation among the nonlinear coefficient β, em and Z2 is established.

All-Silicon Zeolite Supported Pt Nanoparticles for Green On-Board Inert Gas Generation System

ABSTRACT Green On-board Inert Gas Generation System (GOBIGGS) is regarded as one of the most promising routes for fuel tank inerting, whose operation efficiency can be remarkably promoted by an excellent catalyst. In the present work, three kinds of all-silicon zeolite-supported Pt nanoparticles, Pt/Si-Beta, Pt/Si-ZSM-5, Pt/SBA-15 were prepared and characterized. The activities of these catalysts for flameless combustion of fuel samples were investigated on a self-designed apparatus. The results show that among these tested catalysts, Pt/Si-Beta has the best catalytic activity, which can catalyze the complete combustion of methylcyclohexane and aviation kerosene RP-3 at 166°C and 241°C, respectively. The superb activity of Pt/Si-Beta can be ascribed to its striking hydrocarbon adsorption capacity. It can also be found that the 1.0 wt% loading amount of Pt is appropriate to meet the actual demand of the GOBIGGS system, considering catalytic effects and costs. Moreover, Pt/Si-Beta tends to exhibit superior activity and stability even in different humidity and space velocity environments for a long time. It can maintain a conversion rate of around 98% even after 30 h of continuous using. All of these show that Pt/Si-Beta has the potential to be applied to the GOBIGGS system.

Application of the ASTM D5470 standard test method for thermal conductivity measurements of high thermal conductive materials

Purpose: The purpose of the present study was to demonstrate the procedure for determining the thermal conductivity of a solid material with relatively high thermal conductivity, using an original self-designed apparatus. Design/methodology/approach: The thermal conductivity measurements have been performed according to the ASTM D5470 standard. The thermal conductivity was calculated from the recorded temperature values in steady-state heat transfer conditions and determined heat flux. Findings: It has been found from the obtained experimental results that the applied standard test method, which was initially introduced for thermal conductivity measurements of thermal interface materials (TIMs), is also suitable for materials with high thermal conductivity, giving reliable results. Research limitations/implications: The ASTM D5470 standard test method for measurement of thermal conductivity usually gives poor results for high conductive materials having thermal conductivity above 100 W/mK, due to problems with measuring heat flux and temperature drop across the investigated sample with reasonably high accuracy. Practical implications: The results obtained for the tested material show that the presented standard test method can also be used for materials with high thermal conductivity, which is of importance either for the industrial or laboratory applications. Originality/value: The thermal conductivity measurements have been carried out using an original self-designed apparatus, which was developed for testing broad range of engineering materials with high accuracy.

The impact of variable carbonation and decarbonation conditions on the CO2 sorption capacity of CaO-based sorbents

The study focuses on the utilisation of natural limestones for repeatable high-temperature chemisorption of carbon dioxide from flue gas. Two methods are compared to improve the problem of the capacity decrease with repeated uses: the steam regeneration of limestone and the conversion of the same limestone to a CaO-based sorbent via an organic intermediate. Moreover, the study extends the knowledge of the sorption behaviour of the limestones by assessing the impact of the composition of the calcination and carbonation atmosphere measured independently using a self-designed laboratory apparatus with a fluidised-bed reactor. After ten cycles, performed without any regeneration procedure, the capacity achieved by the natural limestones decreased from ca 290 to 370 to only 80 and 130 mg g−1. The application of steam regeneration showed good results in capacity stabilisation. From the fifth to the tenth cycles, the limestones had an average capacity of 220 mg g−1. Steam regeneration was not, however, the only method to improve the capacity effectively. The CaO sample prepared by the chemical modification of the natural limestone was resistant to the drop in capacity and achieved the value of 210 mg g−1 after ten cycles. Since the pilot-scale units used worldwide utilise oxy-fuel combustion flue gas as the decarbonation medium, the influence of pure CO2 on sorption capacity has been investigated as well. This atmosphere supports a decrease in the capacity of limestones, which drops to 30–50 mg g−1 after ten cycles. The CaO sample exhibited higher resistance and maintained the capacity of ca 110 mg g−1. In addition, the influence of the residual concentrations of sulphur dioxide present in the simulated flue gas has been tested. It has been confirmed that SO2 seriously deteriorates sorption properties; therefore, its presence in the gas feed must be avoided.

Ultrasonic flexible microextrusion forming of ZK60 Mg alloy at room temperature

A novel method of ZK60 magnesium formed through ultrasonic flexible microextrusion at room temperature was developed. A self-designed apparatus was applied for the ultrasonic flexible microextrusion experiments. The results showed that the forming ability and surface quality of products was improved via ultrasonic flexible microextrusion forming method. The extrusion stress distribution could be more uniform by using ultrasonic plasticizing flexible punch, compared with rigid punch.

Evaluation of casting fluidity and filling capacity of Zr-based amorphous metal melts

Understanding the flow characteristics of amorphous metal melts is important for casting and molding processes. Fluidity of Zr-based amorphous metal melts was determined by using a self-designed apparatus. Phase analysis demonstrated that the fluidity test samples were fully amorphous structure. The onset crystallization temperature significantly moved toward high temperature with the increases of casting temperature, which improved the glass-forming ability and thermal stability of Zr-based amorphous metal. Fluidity test results demonstrated that the fluidity length increased monotonically with the increases of temperature, pressure, and runner diameter. By identifying the types and quantities of the defect in castings, it could conclude that smooth filling processes occurred under appropriate conditions. Experimental results indicated that the flow behavior of the Zr-based amorphous metal melts strongly depended on the casting temperature and equivalent thickness. Constitutive equation based on Newton’s law of heat exchange and Rayleigh rule was established to evaluate the fluidity of Zr-based amorphous metal melts. Theoretical calculations and experimental tests were basically coincided with each other. The determined optimal casting temperatures and equivalent thicknesses were adopted to successfully fabricate a series of fully shaped castings through gravity casting.

A Study of the Pressure-Induced Solidification of Polymers.

By using a self-designed pressure-jump apparatus, we investigated the melt solidification behavior in the rapid compression process for poly-ethylene-terephthalate (PET), polyether-ether-ketone (PEEK), isotactic polypropylene (iPP), high-density polyethylene (HDPE), and the living polymer sulfur. The experimental results clearly show that crystallization could be inhibited, and some melts were solidified to the full amorphous state for PET, PEEK, and sulfur. Full amorphous PEEK that was 24 mm in diameter and 12 mm in height was prepared, which exceeded the size obtained by the melt quenching method. The bulk amorphous sulfur thus obtained exhibited extraordinarily high thermal stability, and an abnormal exothermic transition to liquid sulfur was observed at around 396 K. Since the solidification of melt is realized by changing pressure instead of temperature and is not essentially limited by thermal conductivity, it is a promising way to prepare fully amorphous polymers. In addition, novel properties are also expected in these polymers solidified by the pressure-jump within milliseconds.

Study of a New Biological Control Method Combining an Enteropathogen and a Chemical Insecticide Against Solenopsis invicta (Hymenoptera: Formicidae).

Solenopsis invicta (Buren; Hymenoptera: Formicidae) is a species that has invaded China in recent years. Currently, S. invicta is mainly controlled by chemical treatment, though long-term use of chemical pesticides can cause serious environmental pollution. In this study, a microbial insecticide formulated for the control of S. invicta was screened for laboratory toxicity and field efficacy. The co-toxicity coefficients (CTCs) of the combination of Beauveria bassiana and thiacloprid at various mass ratios were 356.53, 251.20, 182.50, 215.03, and 143.19. When B. bassiana powder and thiacloprid were mixed at a mass ratio of 8:2, the CTC was 356.53, demonstrating a very significant synergistic effect. According to a field efficacy test, at 3 d after treatment, the efficacy of mound injection was significantly better than that of mound drenching. In this study, the insecticidal activity of pathogenic microorganisms against S. invicta was markedly enhanced by using a self-designed apparatus for mound injection of the tested preparation of a complex containing a pathogenic microbe. The results show that S. invicta can be sustainably controlled while ensuring the safety of the environment. The findings are a good reference for the promotion and application of safe control of S. invicta in the future.

Ultrasonic-assisted extrusion of ZK60 Mg alloy micropins at room temperature

A new model of ZK60 magnesium micropins formed through ultrasonic-assisted extrusion at room temperature was developed. The billet was transmitted by the ultrasonic wave during the micropin-forming process. A self-designed apparatus was applied for the ultrasonic-assisted extrusion experiments. The effects of amplitude on the load–displacement curve, load reduction, temperature, microstructure, diameter after extrusion, microhardness, and compressibility of micropins were investigated. The results showed that the punch was always in contact with the billet when the displacement of the punch was larger than the amplitude. The maximum reduction of load was approximately 80% because of the dynamic recrystallization and ultrasonic softening. In addition, load reduction was almost similar under different amplitudes when the diameters of micropins after extrusion were 0.3 and 0.5mm as a result of the size effect. The microhardness of the micropins increased at the amplitude of 39 and 42μm as compared with the traditional extrusion. This finding was inconsistent with the results for copper and aluminum. The compression ratio of micropins prepared through ultrasonic-assisted extrusion improved by 14–20% on average at room temperature.

Manufacture of low-benzo(a)pyrene sesame seed (Sesamum indicum L.) oil using a self-designed apparatus.

The aim of this study was to lower benzo(a)pyrene (BaP) contents in sesame seed oil (SSO) during manufacture by using a self-designed apparatus, to determine its optimal conditions, and to analyze antioxidants in SSO which might be related to BaP content reduction. Washing and spin-drying steps reduce exogenous BaP contamination, and the reduced moisture in seeds lowered BaP content in final SSO. A ventilation system in the roasting step inhibits BaP formation and reabsorption, followed by a controlled compression step. The optimal condition, a single washing cycle with 2-min spin-drying, 1350-rpm ventilation, and a single compression cycle, reduced the BaP content in SSO to 2.93 μg/kg, where the raw seeds had been spiked with 10-μg/kg BaP. Total phenolic contents showed a reversal pattern to the distribution of BaP contents. Sesamol and sesamolin were quantified by a high performance liquid chromatography-ultraviolet detector, and it was suggested that sesamol which is a strong antioxidant might have prevented BaP formation during the roasting step. This study enabled the commercial production of low-BaP SSO, and the data could be used in further investigations of the BaP content reduction mechanism with quantitative chemical analysis of the SSO composition.