Stainless Steel Rods Research Articles

Trace Detection of Pb(II) using Square Wave Anodic Stripping Voltammetry with Stainless Steel Electrodes

<p>Lead (Pb(II)) is well known as a dangerous environmental contaminant that harms public health worldwide. Early Pb(II) detection before release into the water system is important. This work describes an inexpensive Pb(II) determination using 5 mm diameter stainless steel rod type 304 as a working electrode. Using a batch system, the research employed 10 mL of 0.1 M acetate buffer at pH 4.5. The best operation was at a deposition potential of -1.2V for 300 s. It provides a linear range in the concentration range of 0.075 – 1 µg/mL Pb(II) (r = 0.994). The limit of detection (LOD) and limit of quantification (LOQ) of Pb(II) were at 0.057 µg/mL and 0.189 µg/mL, respectively. Repeatability and reproducibility were expressed in the relative standard deviation range of 1.26-3.71% in the testing a Pb(II) concentration range of 0.2-1.0 µg/mL and 5.32% in testing a Pb(II) concentration of 0.4 µg/mL. A very low-cost stainless-steel electrode proposed a high operational stability up to 10 measurements with RSD of 4.39%.</p>

Influence of Surface Pretreatment on the Bond Strength of a Resin Luting Cement to Saliva-contaminated Enamel and Dentin.

This study aimed to evaluate the influence of surface pretreatment on the shear bond strength (SBS) of a resin luting cement to enamel and dentin with saliva contamination. The surface free energies (SFE) of the adherent surfaces were also determined. Bovine enamel and dentin were used in this study. For the saliva-contamination, human saliva was applied to the adherent surface for 60 seconds and then air-dried, and the specimens without saliva contamination served as controls. One group of contaminated surfaces was untreated (SC), and the others were pretreated with Katana Cleaner (KC), Multi Etchant (ME), or Ultra-Etch (UE). Fifteen specimens were prepared to measure the SBS for each test group.The mixed resin luting cement paste was applied to the alumina-blasted surface of a stainless-steel rod and placed on the prepared tooth surface. The luting cement was light irradiated for 40 seconds. The bonded specimens were stored for 24 hours at 37°C and half of the bonded specimens underwent 10,000 thermal cycles. The SBS and SFE of the specimens after different pre-treatments were measured. The two-way ANOVA revealed that the factors of pretreatment agent and storage condition had a significant effect on the SBS to enamel and dentin. The SFE values of the SC group were significantly lower than those of the other groups in both enamel and dentin. The SFE of pretreated surface was material dependent. A pretreatment agent containing functional monomers was shown to be effective in removing saliva contaminants and in creating an effective bonding surface for the resin luting cement.

Evaluation of Fe Content on the Fluidity of A356 Aluminum Alloy by New Fluidity Index

AbstractElements that are deliberately added to aluminum alloys or are incorporated into the alloy later depending on the production process affect the final product properties. In addition, liquid metal cleaning is important in minimizing undesirable elements. Considering the production process, one of the most harmful impurities that is likely to pass into the alloy via diffusion for aluminum is the element, Fe. It is known that this is due to the fact that although Fe is highly soluble in liquid aluminum and its alloys, it has very little solubility in solids. Depending on the Fe content, mechanical properties, porosity and fluidity properties are affected in aluminum alloys. In this study, stainless and carbon steel rods were dipped into the melt at 700 °C and 750 °C for 1, 2 and 5 h. Castings were performed before and after degassing. Four-channel fluidity mold with different section thickness was used in the trials. Additionally, microstructure characterization was performed under varying casting conditions. Fluidity Index was proposed which is a single value measured from all fluidity values in different sections. When the results were examined, it was determined that the diffusion material, holding time, casting temperature and liquid metal cleanliness had an effect on the fluidity. Due to the increase in diffusion time, a decrease in fluidity was observed in both carbon steel and stainless steel. It was found that fluidity was significantly reduced when using stainless steel.

Thermochemical battery prototypes with conductive heat extraction

Thermochemical energy storage is a viable option for large-scale storage of renewable energy. Functional storage systems require a high cycling capacity and an efficient heat extraction unit to guarantee reliable energy storage and subsequent power production. This article investigates the performance of thermochemical battery prototypes that use conductive heat extraction via metallic rods. The thermodynamics and kinetics of the storage material, CaCO3-Al2O3 (20 wt%), used in the prototypes, were studied along with the cyclic carbon dioxide sorption capacity, which was retained at 60 %. The reaction thermodynamics and kinetics of this doped CaCO3 compound are similar to those reported for pure calcium carbonate (ΔHdes = 173 ± 10 kJ.mol−1 CO2 and ΔSdes = 147 ± 9 J.mol−1 CO2·K−1). The two prototypes were constructed using either a stainless-steel rod or a stainless-steel tube with a copper core as conductive heat exchanger. The thermochemical battery prototypes (∼1 kg) cycled >30 times, with thermal charging (calcination) and discharging (carbonation) at ∼900 °C. The storage material is sensitive to the operating conditions of pressure and temperature, which influence the formation of various calcium aluminium oxide compounds that either catalyse or inhibit the cyclic capacity. The carbon dioxide sorption capacity in the prototypes was found to be limited (20 %) and capacity loss was correlated to the temperature distribution through the storage material and limited by the heat transfer rate of the heat extraction system. The heat transfer performance of the stainless-steel rod was inadequate, while the copper core allowed for better system performance.

Optimize the corrosion behaviour and mechanical properties of AISI 316 stainless steel under heat treatment and previous cold working

Abstract Improving corrosion resistance in alloys made of stainless steel is an important innovation on the petroleum trade. The effect of heat treatments (HT) and cold working on the corrosion behaviour, surface hardness, and microstructure of 316 stainless steel was investigated experimentally. The corrosion environment is seawater and crude oil. The corrosion rates (CRs) were obtained using the mean loss of weight approach, which was then optimised using the Taguchi method. The specimens used in this study are made of 316 stainless steel rod, which is first annealed to obtain the qualities of the raw material before being put through a tensile test to assess the mechanical characteristics of the metal. After cold working, the hardness test, the corrosion test utilising the lost weight method, and the microstructure test are all carried out. By performing these tests, the metal show excellent mechanical properties such as yield stress, tensile stress, and hardness; in the corrosion test, the raw metal show higher resistance in both seawater and crude oil, while in cold working and HT with cold working, samples show higher corrosion The HT samples had the lowest corrosion resistance as the cold working percentage increased. In this work, the input parameters such as ultimate corrosion media, HT and cold work (CW) are optimised utilising a multiple objective optimisation approach that uses weighted grey relational analysis. Two objectives, that are CR and Hardness (H), are simultaneously optimised. We suggested a quantitative approach to establish the weight factors of various responses for grey relational analysis called weighted grey relational analysis. The optimum input parameters were determined using weighted grey relational analysis, and the outcomes showed that HT is the most relevant parameter. Cold working has been observed in association with stress-related twinning and austenite phase deformation, resulting in fast grain splitting and the production of a microstructure that resembles a ribbon composed of austenite and ferrite.

475 Molybdenum-Rhenium Rods in Complex Adult Spine Surgery Without Rod Fractures: A Multicenter Retrospective Case Series

INTRODUCTION: In complex spine surgery, current pedicle screw systems with 5.5 mm titanium, cobalt chromium or stainless steel rods have rod failure rates of approximately 9% with a minimum of 1-year follow-up. The fracture rate with these alloys increases to approximately 22% in PSO cases.1 Molybdenum-rhenium has demonstrated superior yield strength and fatigue endurance limit compared to Ti-6Al-4V and CoCr. METHODS: Retrospective, multicenter, case series. Inclusion criteria were = 4 levels posterior instrumented fusion with 4.5 mm molybdenum-rhenium rods, age = 18 yrs and 6 months or longer radiographic and followup. RESULTS: One hundred and fifty-nine (159) consecutive patients from ten different medical centers that had spinal surgery from August 2019 until April 2022 met inclusion criteria. Mean age was 63 ± 11.8 years; 50% women; 31% smokers; 19% diabetic and the mean BMI was 30 ± 7.3. The mean number of levels fused was 5.9 ± 2.7; 22.6% 4 levels, 64.2% 5-9 levels and 13.2% 10 levels or greater. Approximately half were thoracolumbar (27.7%) or thoracolumbar to pelvis (24.5%) and approximately half were lumbar-sacral (47.2%). Thirty-eight patients (24%) had a PSO and 59 patients (39%) had a SPO. All cases were done with molybdenum-rhenium 4.5 mm diameter rods. There were no RFs reported in the 159 cases (0/159; 0.0%) at 22.36 months mean follow-up. CONCLUSIONS: There was no incidence of RF in the 159 consecutive patients who underwent complex spine surgery involving multiple levels and osteotomies. A pedicle screw system based upon molybdenum-rhenium 4.5 mm rods provides superior fracture resistance particularly in complex spine procedures. 1 Smith JS, et al., Prospective multicenter assessment of risk factors for rod fracture following surgery for adult spinal deformity. J Neurosurg Spine. 2014 Dec; 21(6): 994-1003.

Comparing Various Resin Luting Cement Systems in Different Etching Modes Through Bond Durability and Morphological Features.

This study aimed to investigate bond performance of various resin luting cement (RLC) systems on enamel and dentin in different etching modes and to compare the RLC-tooth interface morphology using scanning electron microscopy (SEM). The self-adhesive RLC systems used in combination with universal adhesives were as follows: Scotchbond Universal Adhesive Plus + RelyX Universal (3M Oral Care) and Clearfil Universal Bond Quick ER + SA Luting Multi (Kuraray Noritake Dental). These RLC systems were also used alone as self-adhesive RLC systems without universal adhesives (self-adhesive mode). The conventional RLC systems for comparison materials were as follows: BeautiBond Xtream + ResiCem EX (Shofu) and Tooth Primer + Panavia V5 (Kuraray Noritake Dental). Twelve specimens were prepared for each group to measure shear bond strength (SBS) in different etching modes. A stainless-steel rod was used as a substitute for indirect restorations. Bonded specimens were allocated to baseline (stored for 24 hours) and artificially aged (thermocycling [TC] for 10,000 cycles) groups. Representative treated tooth surfaces and RLC-tooth interfaces were observed using SEM. Three-way analysis of variance (ANOVA) revealed that all the factors (etching mode, storage period, and RLC system) had a significant influence on the enamel SBS values (p<0.05). Enamel SBS was significantly higher in etch-&-rinse (ER) mode than in self-etch (SE) mode, regardless of RLC system or storage period. Three-way ANOVA showed that all the factors had a significant influence on the dentin SBS values (p<0.001). Most RLC systems showed significantly higher dentin SBS in SE mode than in ER mode, regardless of storage period. However, the combination with Scotchbond Universal Adhesive Plus and RelyX Universal showed no significant difference in SBS values between etching modes at the baseline and showed a significantly higher SBS value in ER mode than in SE mode after TC. The self-adhesive RLC systems with universal adhesives tended to show higher enamel and dentin bond performance than the self-adhesive RLC systems alone. The morphology of treated tooth surfaces and resin cement-tooth interfaces were dependent on the RLC system and etching mode used. The RLC systems with primer application showed a thin, high-density layer above the intact dentin in both etching modes, suggesting chemical interaction.

Semi-analytical solution to elastic–plastic contact-impact between a 316 stainless steel rod with truncated cone nose and rigid flat

When subjected to impacts, rods suffer local large deformation and global vibrational deformation along with abrupt kinematic and mechanical response changes. Studies on the responses during impact are beneficial to structural health monitoring. In this study, both kinds of deformation of rods with truncated-cone noses were investigated. A semi-analytical solution describing the vibrational responses of the rod was obtained based on the plastic contact model of the truncated-cone nose against a rigid flat and the one-dimension hypothesis of the rod. The theoretically predicted results agreed well with those calculated by finite element model (FEM), and the scaling law in rod response was theoretically derived and verified by FEM. Besides, the compression degree of the rod with three truncated-cone noses was considered, and the rod nose of lower contact stiffness presented better buffering effects. Finally, the applicability map of the semi-analytical solution was depicted according to the scope of the contact model.

Influence of different curing modes on the bonding effectiveness of self-adhesive resin luting cements in combination with universal adhesives

ObjectivesThis study aimed to investigate the immediate dentin bond performance and bond durability of self-adhesive resin luting cements (RLCs) in combination with universal adhesives in different curing modes. MethodsTwo self-adhesive RLCs were used with universal adhesives as primers. They were also used alone as self-adhesive RLCs. Two multiple-step RLC systems were used as comparison materials. To measure the shear bond strength (SBS) in different curing modes, 12 specimens were prepared for each group. Stainless-steel rods were bonded to bovine dentin, and the bonded specimens were assigned to the baseline group (stored for 24 h) and artificially aged group (thermal cycling [TC], 10,000 cycles). After each storage period, the SBS of the bonded specimens was measured. The Knoop hardness number (KHN) of the cured RLCs was measured with or without primer application in different curing modes at 24 h and after 10,000 TC. The representative RLC/dentin interfaces were observed using scanning electron microscopy (SEM). ResultsDentin SBS was significantly influenced by the RLC system but not by the curing mode. Self-adhesive RLCs alone showed significantly lower SBS values than self-adhesive RLCs with primer regardless of the curing mode or storage period. The storage period, curing mode, and RLC system significantly influenced the KHN. SignificanceThe use of universal adhesives as a primer may help enhance the immediate dentin bond performance and bond durability of self-adhesive RLCs.

The effect of low-electrical voltage as a method to eradicate Acinetobacter baumannii bacteria

Introduction: Acinetobacter baumannii is one of the bacteria in critical priority according to WHO in 2017 and one of the causes of nosocomial infections in the world. These bacteria usually become resistant to antibiotics (Multi Drug Resistant Organism, MDRO), infect the bloodstream, and cause pneumonia. This study aimed to examine the effect of low-voltage electricity as a method to kill Acinetobacter baumannii by using a different electric current. Methods: This study is experimental research in the Microbiology Laboratory of RSAB Harapan Kita. Experiments were carried out using a solution of Acinetobacter baumannii non-MDRO and MDRO bacteria with a parallel design device opposite to the GPS 3030D power supply with a power of 90 W. Each tube was fitted with a 12 cm stainless steel rod conductor with a diameter of 3 mm and delivered amperage 1 mA, 2 mA, 5 mA, and 10 mA and 0.5V with each amperage performed 5 times and measured using DensiCHEK. Result: From 20 Acinetobacter baumannii non-MDRO experiments and 20 MDRO experiments, it was found that from 1 mA, 2 mA, 5 mA, and 10 mA with monitoring time of 30 minutes, 2 hours, and 4 hours, the results of bacterial eradication by DC stimulation with 5 mA and the most optimal time is 30 minutes according to what has been applied. Conclusion: Using an electric current of 5 mA and a duration of 30 minutes can reduce Acinetobacter baumannii MDRO and non-MDRO bacteria with more optimal results in the non-MDRO group.

An Improved Fixture to Quantify Corrosion in Bolted Flanged Gasketed Joints

Abstract This study discusses the corrosion behavior of bolted flanged gasketed joint systems. A novel fixture is proposed to quantify the corrosion at the gasket–flange interface under service conditions. Due to the presence of crevices and potential differences between gaskets and flanges, corrosion widely occurs in such joints. Crevice corrosion and galvanic corrosion can create paths to leakage of the pressurized fluid and may cause catastrophic failure. Corrosion in bolted gasketed joints was investigated previously; however, the effects of the operating conditions were not reported. Operating conditions include fluid flow, pressure, pH, conductivity, temperature, and average gasket contact stress. This study starts by introducing a new experimental setup to examine the corrosion behavior of bolted flanged gasketed joints. The developed fixture consists of a pressurized bolted gasketed joint that enables real-time monitoring and recording of the corrosion parameters under the influence of service conditions. Second, potentiodynamic polarization testing is conducted to measure the corrosion rate and obtain data on the corrosion behavior of a pair of flange and gasket materials. These tests are performed using the novel setup that reproduces the behavior of industrial bolted flanged gasketed joint systems. It consists of a working electrode (flange material), a reference electrode (Ag/AgCl), and an auxiliary electrode (a stainless steel rod). Three types of graphite gaskets compressed in the fixture are subject to electrochemical corrosion tests with a 0.6 M NaCl solution. The morphology of the specimen's corroded surfaces is examined via confocal laser microscopy.

Experimental investigation of radiative heat propagation in a simplified generic packed bed

A novel test rig for the investigation of radiative heat transfer in packed beds has been developed and is introduced with representative experimental results. The individual components and the calibration are discussed. The generic packed bed is realized in a simplified way by an arrangement of parallel rods, which represent particles in pseudo-2D. In this arrangement, electrically heated rods provide the radiation propagating through the rod array to heat the passive counterparts. A sophisticated temperature-control scheme with a large number of thermocouples and infrared-imaging provides in-depth information about heat transfer in the system. Spectral radiation intensities are determined with a Fourier-transform infrared spectroscopy, which has been modified and validated for this specific application. In order to compare the influence of different surface properties of particles on the heat propagation and surface reflections, rod samples made of stainless steel and magnesium oxide are used. The influence of material properties becomes clearly visible by comparing the high radiation intensities resulting from a stainless steel rod array to the same geometry built from magnesium oxide rods. In addition, the influence of the surface properties is particularly evident in the infrared images since the reflections are significantly higher for the stainless steel samples than for the magnesium oxide samples. The experimental results in the current work demonstrate the ability of the test rig to provide data with a well-defined accuracy as a validation base for numerical radiation simulations in packed beds.

Electrical Conductivity of Low-Temperature KF-Naf-AlF3 Melts with CaF2 and Al2O3 Addition

Replacing consumable carbon anodes with oxygen evolving inert anodes, in aluminium reduction cells, has long been a goal for the aluminium industry. Using inert anodes would have several advantages, one of them being the elimination of greenhouse gas emission during the electrolysis process. Metallic alloys have proven to be a promising category of material candidates for inert anodes. The industrial electrolyte is a cryolite based fluoride, and the process temperature is around 960°C. This is a very corrosive environment for the anodes, which have failed to be inert. Lowering the electrolysis temperature is key to improving anode performance. The liquidus can be lowered by reducing the NaF ratio, often termed Cryolite Ratio (CR), of the NaF-AlF3 melt, but that is not feasible as it drastically reduces the alumina solubility. If some, or all, of the NaF in the melt is replaced by KF, acceptable alumina solubility is maintained even at the low CR necessary for melting point down to 700°C. Replacing NaF with KF is known to reduce the electrical conductivity, and therefore it is of interest to determine the electrical conductivity of KF-NaF-AlF3-Al2O3 melts with different parameters. In the present study, we determine the electrical conductivity of KF-NaF-AlF3 melt at different parameters such as temperature, cryolite ratio (CR = xNaF+xKF/xAlF3), potassium ratio (xKF/xKF+xNaF) and composition of CaF2 and Al2O3 additives. Continuously varying cell constant (CVCC) technique is used to determine the electrical conductivity of the melt, which is governed by equation (1). (1)Here κ is the electrical conductivity of the melt in S cm−1, A is the cross-sectional area of the conductivity cell in cm2, l is the length of the cell in cm, and Rm is the melt resistance in Ω. The experiments are performed at various cell geometries, as shown in figure 1a.Electrochemical impedance spectroscopy (EIS) is used to determine the resistance (R) of the conductivity cell. AC-technique with a small amplitude of 10 mV and high frequencies ranging from 100 Hz to 100 kHz is used. R = Rm + Rp + Rc (2) Rm is the melt resistance, Rp is the polarisation resistance, and Rc is the resistance related to electrical connections. When EIS is performed at different l values, Rp and Rc remain constant while Rm changes. Thus, the Rp+Rc value can be estimated by extrapolating the line plotted between R and cell constant to 0 (cell constant value) (see figure 1b). Figure 1a. Conductivity cell: 1: Stainless steel rod, 2: Alumina tube, 3: BN tube, 4: Molten electrolyte, 5: Counter electrode electrical connector, 6: Graphite working electrodes, 7: Graphite crucible/counter electrode, 8: k-type thermocouple. 1b. An example graph plotted between the cell resistance and cell constant to estimate the melt resistance. Figure 1

Turbidity Removal from a Model Solution by Continuous Mode Electrocoagulation and Evaluation of Energy Consumption

The purpose of the research has been the construction of a new electrocoagulation (EC) equipment and its technical evaluation in the treatment of a model solution with a high level of turbidity. The EC system contains six cells installed in series, coupled to a flocculator and a clarifier (sludge decanter), each cell unit is composed of a cylindrical aluminum (Al) anode and a solid stainless-steel rod as cathode in connection with a DC power supply, the aluminum anodes are replaced by iron (Fe) according to the proposed tests. The influence of two factors, such as the applied electric potential and the type of electrode used, on turbidity removal performance, total dissolved solids (TDS) and electrical energy consumption were examined. The tests were carried out using a two-factor factorial design, electrical potential at (0, 3, 6 and 9 V) and type of anode (aluminum and iron). The investigation of the operating parameters was carried out in continuous mode. The initial turbidity of the water to be treated was set at 84.5 NTU, a value generally found in surface water. The results showed that the best conditions for turbidity removal were at an electrical potential of nine volts reaching a removal of 82.29 % and an energy consumption for aluminum electrodes of 0.7142 kWh/m3. It is also observed that the value of total dissolved solids after treatment is still slightly high. In conclusion, electrocoagulation with Al/steel electrodes proved to be an appropriate technology for water treatment due to its turbidity removal efficiency and low electrical energy consumption.

Recycling metal cutting chips into a consolidated deposition with friction surfacing

The objective of this research is to evaluate the feasibility of using metal cutting chips as a feedstock in solid-state metal additive manufacturing, with friction surfacing used as a demonstrator. To date, the recycling of metal cutting chips is an energy-intensive process. Compared to recycling processes that melt down metal chips, friction surfacing is a solid-state process, which should reduce the overall embodied energy needed to reuse the chips. While friction surfacing is primarily used for coating surfaces to improve their wear properties, it is also showing promising results as an additive manufacturing process for repair / remanufacturing features on large metal parts. Metal cutting chips of 316L stainless steel, produced by a milling operation, were pressed into hollow 304L stainless steel rods. The chip-filled rods were used as the [consumable] friction surfacing tools to deposit on 304L stainless steel substrates. The properties of the resultant deposits are analyzed and compared with deposits made by solid 304L and 316L tools, including deposition geometry, efficiency, process forces, and bond strength. Results indicate that a fully consolidated deposition can be created from the metal cutting chips using this process. Compared with a solid 304L tool, deposits made with metal chip-filled tools were narrower but thicker in the steady-state region when deposited with the same process parameters.

Analgesic Effect of Tuina on Rat Models with Compression of the Dorsal Root Ganglion Pain.

Neuropathic pain is a prevalent condition that affects 6.9%-10% of the population and results from nerve damage due to various etiologies, such as lumbar disc herniation, spinal canal stenosis, and intervertebral foramen stenosis. Although Tuina, a traditional Chinese manual therapy, has shown analgesic effects in clinical practice for the treatment of neuropathic pain, its underlying neurobiological mechanisms remain unclear. Animal models are essential for elucidating the basic principles of Tuina. In this study, we propose a standardized Tuina protocol for rats with compression of the dorsal root ganglion (DRG), which involves inducing DRG compression by inserting a stainless steel rod into the intervertebral foramen, performing Tuina manipulation with specific parameters of location, intensity, and frequency in a controlled environment, and assessing the behavioral and histopathological outcomes of Tuina treatment. This article also discusses the potential clinical implications and limitations of the study and suggests directions for future research on Tuina.

Identification of predominant bacterial species involved in microbial fuel cell assisted electricity generation using fish market wastewater

Microbial Fuel Cells (MFCs) are a rapidly expanding area of sustainable technology that treats wastewater and generates energy from biodegradable wastes at the same time. However, the power generation from MFC is strongly restricted by the biofilm (microorganism) electron transfer rate which improves electrical power density. The current study provides insight into the effectiveness in electricity production, and wastewater treatment using MFC technique by identifying microbial electricigens on various electrodes using raw fish market wastewater effluent as a substrate. Galvanised iron, aluminium, brass, stainless steel (metal-based electrodes), and graphite rod (carbon-based electrode) were used for the study. MALDI-TOF MS tests were performed to identify the predominant bacterial species from each electrode containing reactors. Raoultella ornithinolytica, Comamonas testosteroni, and Klebsiella pneumonia were among the microbes that were identified and isolated from the anodic biofilm of different MFC reactors. In the current study, four out of the five reactors contained R. ornithinolytica, which was found to be effective at generating electricity. The fuel cell produced maximum current density of 325.13 mA/m2, and power density of 87.78 mW/m2. The COD removal efficiency was found to be 86 %. This study demonstrates the significance of bacterial community characterization and identification in MFC-assisted current generation in fish market wastewater.

Liquid jet dispersion after impact on a highly curved surface

A liquid jet impacting on a wire mesh is a phenomenon that occurs in such industrial applications as rotating packed beds or agricultural spraying. To derive a fundamental understanding of the behaviour of a dispersion generated by the whole mesh, a simple geometric case needs to be studied. This paper focuses on the dispersion of a liquid jet impacting on a single stainless steel rod studied with a high-speed visualisation. It is found that two liquid sheets are formed with sheet characteristics described by a dispersion angle αe, a sheet velocity vs, and a breakup length Lb. Three stages of the angular development of the dispersion are observed based on the liquid flow rate and the exit orifice diameter. A correlation for the dispersion angle growth is proposed based on the experimental results. Perforated, segmented and wave-assisted sheet breakup regimes are found in the recorded images with their presence dependent on the impact velocity. A correlation for the breakup length is proposed for the sheets based on similarities with flat fan nozzle theory.

Experimental Investigation on Cooling Performance of Borated Water During Immersion Quenching at the Saturated and Sub-Cooled Conditions

Film boiling occurs when an overheated sample is rapidly plunged into the liquid. The study of film boiling is paramount in many engineering applications, like, cooling of nuclear reactor fuel rods, regenerative cooling of rockets, and wet treatment of blast slag furnaces. The objective of the present study is to explore the influence of boric acid at various concentrations (0.5%, 1%, 3%, and 5% vol.) and subcooling temperature on film boiling heat transfer using stainless steel rod (304 L). We performed vertical immersion quenching experiments in subcooled (50 °C) and saturation temperature at atmospheric conditions. Under saturated conditions, the sample quenched in deionized water took 73 s to cool down to 100 °C, while in the subcooled condition, the sample only took 13 s. At both saturated and subcooled conditions, 1% vol. boric acid solution accelerated the quenching rate and facilitated lowest film boiling time than other solutions considered. Conversely, film boiling time is higher when the sample is quenched in deionized water with 5% vol. of boric acid. The coolant temperature and additive concentration influence the film boiling time and Leidenfrost temperature, with a local build-up of boric acid concentration at the liquid–vapor interface being the governing mechanism.

3D fatigue crack path deflection and residual stresses in 17-4PH stainless steel rod

Damage tolerant structures require accurate fatigue crack growth rate models for life prediction. Central to these models are fracture mechanics similitude and empirically gathered growth rates. In this work, standard test methods failed to achieve similitude for 17-4PH stainless steel round-rod but succeeded for plate. Material product form differences are interrogated through constant ΔK tests, crack path analysis, residual stress (RS) characterization, and growth rate simulation. Analyses revealed that quench-induced RS in the round-rod promoted a non-planar, 3D crack path with closure effects. Strategies to mitigate the RS/path effects are evaluated by controlling constraint, closure, environment, and heat treatment.