Water Chamber Research Articles

Исследования процессов удаления воздуха из трубопроводов балластных систем плавучих доков

Object and purpose of research. The objective of the study are modern technical solutions for removal of air masses penetrating into the pipelines of ballast systems of floating docks used in shipbuilding. The purpose of the paper is to determine the effectiveness of various design solutions and special devices used in the process of design, construction and operation of floating docks by modeling the separation processes of aerated spatial flows in pumping chambers and collectors of ballast systems in experimental installation. Materials and methods. Official information materials in the field of science and technology in the area of analytical and experimental studies of air removal processes in marine systems. Methodology of fluid mechanics, methods of dimension theory, experimental methods. Main results. Achievements in the field of design, construction and operation of ballast systems for floating docks and floating drilling rigs, as well as in hydraulic structures were considered. To control the processes of separation and removal of air penetrating into suction pipelines, tests of a number of special technical solutions used in ballast systems of floating structures were carried out on an experimental hydraulic installation using modifiable models according to the developed program and methodology. In connection with the well-known continuing problem of prolonging the operation of ballast pumps at the final stages of deballasting of floating dock compartments, an experimental assessment of the ingenuity and progressiveness of a number of layout design solutions used in the water ducts of pumping compartments of floating docks was carried out. In ballast systems, imperfections of internal devices in collecting pipelines-collectors and pumping chambers were manifested, due to the hydromechanical phenomena of the interaction of two-phase flows in an enclosed confined space. The current state of the art is characterized by the insufficient level of knowledge of flows in the conditions under consideration governing the development of the objects under study at the present stage. The main patterns of excessively aerated flows behaviour in conditions of ballast system ducts in pumping compartment with physical parameters set, according to the specifications, for the standard pumping equipment used in the systems, are revealed. The performed studies fill in the missing information about the behaviour and interaction of aerated flows inside collectors and pumping chambers of various structural designs. The characteristic significant reasons hindering the optimization of the ongoing separation processes are identified, promising design directions for improving the applied ballast systems are identified. Conclusion. The achieved results of the development allow us to make rational decisions about the use of a specific type of equipment and outfit in certain operating conditions as part of ballast systems of floating docks and other floating structures of similar purpose. The proposed technical solutions are relevant for the development of a more advanced structural design of collecting pipelines and pumping chambers. Experimental materials are also suitable for the development of requirements in design of ballast systems of floating docks and other floating structures with high-performance pumps. The obtained data on behaviour of aerated spatial fluid flows inside closed chambers with a variable flow section as the medium flows to the pump can also be useful in designing rational water chambers in hydraulic structures with high-performance vane pumps.

NEMA characterization of the SAFIR prototype PET insert

BackgroundThe SAFIR prototype insert is a preclinical Positron Emission Tomography (PET) scanner built to acquire dynamic images simultaneously with a 7 T Bruker Magnetic Resonance Imaging (MRI) scanner. The insert is designed to perform with an excellent coincidence resolving time of 194 ps Full Width Half Maximum (FWHM) and an energy resolution of 13.8% FWHM. These properties enable it to acquire precise quantitative images at activities as high as 500 MBq suitable for studying fast biological processes within short time frames (< 5 s). In this study, the performance of the SAFIR prototype insert is evaluated according to the NEMA NU 4-2008 standard while the insert is inside the MRI without acquiring MRI data.ResultsApplying an energy window of 391–601 keV and a coincidence time window of 500 ps the following results are achieved. The average spatial resolution at 5 mm radial offset is 2.6 mm FWHM when using the Filtered Backprojection 3D Reprojection (FBP3DRP) reconstruction method, improving to 1.2 mm when using the Maximum Likelihood Expectation Maximization (MLEM) method. The peak sensitivity at the center of the scanner is 1.06%. The Noise Equivalent count Rate (NECR) is 799 kcps at the highest measured activity of 537 MBq for the mouse phantom and 121 kcps at the highest measured activity of 624 MBq for the rat phantom. The NECR peak is not yet reached for any of the measurements. The scatter fractions are 10.9% and 17.8% for the mouse and rat phantoms, respectively. The uniform region of the image quality phantom has a 3.0% STD, with a 4.6% deviation from the expected number of counts per voxel. The spill-over ratios for the water and air chambers are 0.18 and 0.17, respectively.ConclusionsThe results satisfy all the requirements initially considered for the insert, proving that the SAFIR prototype insert can obtain dynamic images of small rodents at high activities (sim 500 MBq) with a high sensitivity and an excellent count-rate performance.

Corrosion behavior of TiN layer fabricated by laser irradiation of Ti target in N2/liquid water environment

Laser modification of the titanium (Ti) surface is a practical method to improve Ti mechanical properties such as hardness, corrosion resistance as well as wear resistance. Herein, we presented a simple, cost-effective, and green process to generate the ceramic structure of titanium nitride (TiN) on the Ti metal surface. In this research, for the first time, N2 gas was purged in distilled water chamber and was used as an irradiation environment. The effect of various laser scanning cycles on the structure and corrosion resistance of irradiated samples has been investigated. Different analytical methods were applied to study the characteristics of the irradiated Ti samples. The analysis results confirmed the TiN formation in all laser scanning cycles and a small amount of TiO2 at higher laser scanning cycles. In addition, the Ti surface treatment using laser clearly affects the corrosion behavior in Ringer's solution. The obtained TiN layers show lower corrosion current density and higher polarization resistance than bare Ti. Therefore, by laser irradiation of Ti in N2/liquid water environment, the TiN layer is easily formed, presenting desirable surface properties in the corrosion resistance.

High efficient and continuous recovery of iodine in saline wastewater by flow-electrode capacitive deionization

Iodine (I) is a non-renewable and important scarce resource and an essential trace element for human body. Meanwhile, the low concentration radioactive iodine produced by the nuclear industry can cause serious harm to the environment and human beings. The purpose of this study is to investigate the removal and recovery of low-concentration iodine in wastewater by flow-electrode capacitive deionization (FCDI) technology to achieve sustainable utilization of iodine. We systematically investigate the effect of FCDI on iodine enrichment performance under different operating parameters. The results indicate that compared with Cl−, I− is preferentially removed. Cl− and I− have different removal behaviors from brackish water to brine concentration, but I− show a better removal behavior and has a higher selectivity. The iodine removal efficiency remains above 96% after continuous100 cycles under the optimal operating parameters of the FCDI unit with high charge utilization efficiency. Long-term batch experiments show that the low-concentration feed iodine solution (100 mg/L) can be effectively concentrated to 18 times after 24 h operation, with the final iodine concentration dropping to 8.2 mg/L in the feed water chamber and rising to 1818.5 mg/L in the concentration chamber. Overall, the excellent concentration effect, high removal efficiency, and low-energy consumption of the FCDI system in the iodine removal and recovery make it a promising method for the treatment of iodine-containing wastewater.

Electrodialysis ion-exchange membrane bioreactor (EDIMB) to remove nitrate from water: Optimization of operating conditions and kinetics analysis

Nitrate pollution has become a worldwide problem. In this study, we remove nitrate from water by electrodialysis ion-exchange membrane bioreactor (EDIMB) and enabling simultaneous nitrate enrichment and denitrification. In this reactor, nitrate migrated from the water chamber to the biological chamber via electrodialysis and was degraded by microorganisms. The effects of voltage and biomass concentration on the reactor performance were examined, and the kinetics data of the water chamber and biological chamber were fitted. The experimental results showed that the migration of nitrate in the water chamber conformed to the first-order model, and the constructed zero-Michaelis-Menten model described changes in nitrate concentration in the biological chamber. Furthermore, when the inflow nitrate concentration was 40 mg N/L, 5 V was the best voltage, and 3.00 g VSS/L was the best biomass concentration. The nitrate removal rate in the water chamber was 98.94%, and there was no accumulation of nitrate or nitrite in the biological chamber. Compared with traditional ED processes, the nitrate removal efficiency was 8.86% higher, and the current efficiency was 22.14% higher. The total organic carbon (TOC) of the water chamber was only 1.43 mg C/L, which proves that the structure of the EDIMB confined the denitrifying bacteria and organic carbon donors in the biological chamber and avoided secondary pollution in the water chamber. Microbial community analysis showed that Thauera (66.06%) was the dominant bacterium in the EDIMB system, and Azoarcus (9.81%) was a minor denitrifying genus.

Mechanism to form ring-like distributed oxidation-induced stacking fault bands through relaxing thermal stress during stopping the growth in CZ silicon crystals

This paper aims to study the mechanism to form ring-like distributed oxidation-induced stacking fault (R-OSF) bands in CZ silicon. In this experiment, pulling crystals was stopped during the growth, and the crystals were held for predetermined periods contacting the melt while the seed rotation and converse crucible rotation were maintained. Then, the crystals were detached from the melt and cooled rapidly to freeze the defect distribution. In CZ crystals during the growth, high-temperature mass (crystalized silicon) is transferred upward from the growth interface with the crystal pulling. The top of the crystals is directly cooled by the cooling water chamber, while the peripheral part is heated by the radiation from the heater through the gap under the heat shield and the radiation from the melt surface. Thus, the temperature of the upper center part becomes lower than that of the peripheral part, and isotherms in the crystal form U-shape. When the growth is stopped, the crystals also stop raising the “high-temperature mass” from the growth interface. Thus, cooling rapidly proceeds from the center upper part to the growth interface, and the U-shape isotherms fall downward. When the temperature of a region along a U-shaped isotherm decreases to around 1000 ℃, and a temperature gradient exceeding a certain threshold also forms vertically to the U-shaped isotherm, a thermal stress (expansion stress) is applied from the high-temperature side part to the low-temperature center part. At this time, oxygen precipitates, the nuclei of the R-OSFs, are presumably generated there to relax the thermal stress. Although some researchers have presumed that the R-OSF band is a vacancies (Vs)/interstitials (Is) boundary formed at a temperature near the melting point, the results of this study contradict their presumption.

Implementation of an ultrasonic fluid manipulation experiment on the International Space Station

The International Space Station (ISS) provides a unique opportunity to investigate acoustic radiation force interactions with a minimal interference from gravity. There are many design considerations to make when creating an experiment that is suited for use on board the ISS. NASA’s primary concerns with all experiments implemented in the ISS are with the safety of the crew and the success of the mission. Acoustic experiments are surprisingly rare on the ISS and present additional unique design challenges. This is especially true for experiments operated under water. Our work implements a high-intensity acoustic vortex beam under water for single droplet tractoring and capture operated inside the Microgravity Science Glovebox (MSG) on the ISS. The experiment payload consists of a signal generator, an amplifier module, and a sealed water chamber. A secondary fluid immiscible with water is injected into the chamber for acoustic manipulation, and the results of the experiment are recorded as high-definition video.

Implementation of Bubble Continuous Positive Airway Pressure in the Delivery Room and NICU.

Implementation of Bubble Continuous Positive Airway Pressure in the Delivery Room and NICU.

Influence of phosphate layer on adhesion properties between a steel surface and an organic coating

In this paper, tests of some physico-chemical properties of protective epoxy coating on non-alloy structural steel grade type S235JRG2 have been carried out. This is a significant construction material whose use is remarkably important for many steel products such as H beam, I beam, transmission towers, steel pipe etc. Coatings represent one of the ways to protect metal from corrosion. The properties of coating thickness, hardness, gloss, and adhesion were investigated. The same properties were tested by exposing the sample non-alloy steel plates to corrosive conditions of the salt and humid chamber and seawater. Part of the samples prior to application of the coating were immersed to phosphate solution to further investigate the effects of phosphatization on the properties of the coating. After exposure of the plates to the humidity chamber conditions, no traces of corrosion products, cracking or peeling of the coating were found on the surfaces. The plates tested in the sea water and salt chamber showed a minor damage on protective coating. The traitability properties were tested by the Pull off Adhesion test. Force pull adhesion off test shows less value for unphosphated samples than for phosphated ones.

Complexity and bifurcations in the motion of a self-propelled rectangle confined in a circular water chamber.

We consider the motion of a self-propelled object of rectangular shape inside a circular water chamber. The mathematical model of self-motion includes equations for the orientation and location of the rectangle and reaction-diffusion equation with an effective diffusion coefficient for the time evolution of the surface concentration of active molecules. Numerical simulations of motion were performed for different values of the ratio between the supply rate S and the evaporation rate a of active molecules. Treating S0 = S/a as a control parameter, we found the critical behavior in variables characterizing the trajectory and identified different types of motion. If the value of S0 is small, the rectangle rests at the chamber center. For larger S0, a reciprocal motion during which the rectangle passes through the center is observed. At yet higher supply rates, the star-polygonal motion appears, and the trajectory remains at a distance from the chamber center. In the experiments with a rectangle made of camphor-camphene-polypropylene plastic moving in a Petri dish, we observed the transition from the star-polygonal motion to the reciprocal motion in time. This transition can be understood on the basis of the developed model if we assume that the supply rate decreases in time.

Investigating the ability of bacteria isolated from various artificial respiratory systems to resist antibiotics and biofilms formation

Respiratory infections associated with ventilators represent a significant risk to individuals in intensive care units, particularly children under 3 years of age. 100 sample were collected Between October 2021 and February 2022, from Mosul hospitals (Ibn Al-Atheer Teaching Hospital, Ibn Sina Teaching Hospital, Al-Salam Hospital, and Al-Khansa Teaching Hospital) at ages 1 day to 3 years. A swab was taken from the water chamber of the artificial breathing devices, and the catheter head was collected, where the mucous material was cultured in three different mediums (blood agar, MacConkey agar, and Chocolate agar). 80 bacterial isolates were collected. The highest percentage was determined to be connected to Gr- bacteria, with 65 isolates 81.25%, and 15 isolates 18.75% being Gr+ bacteria. Using the Kirby-Bauer disc diffusion method, it was discovered that all isolates had great resistance to the antagonist’s ampicillin and ceftriaxone, but high sensitivity to both Imipenem and Meropenem. The tube method was found to be more efficient than the Congo red agar method in the detection of biofilms. Klebsiella pneumoniae, Stenotrophomonas maltophilia, Burkholderia cepacia group, and Pseudomonas mendocina were biofilm-forming in both ways by up to 100%. The current investigation found that the tube approach produced 100% biofilm, but the Congo red agar method produced 41.25% biofilm.

Characterization of Carbonatation Rate of Alkali-Activated Blast Furnace Slag in Various Environments

Carbonatation represents one of the potential degradation processes whose can negatively affect the service life of constructions based on the inorganic binders. The carbonatation depth of the constructions when exposed to various environments is significantly dependent on the existing conditions. The most crucial parameters are the partial pressure of carbon dioxide and humidity. There were selected four environments for the deposition of samples made of the alkali-activated blast furnace slag mortars (exterior, interior, water and CO2 chamber) in this study. These types of environments guarantee the variation of desired parameters influencing the carbonatation rate. The progress of carbonatation was evaluated with a selected technique in time intervals of 28; 56 and 84 days of the sample's exposition to the selected environments. The characterization was done using the destructive techniques (compressive and flexural strength, phenolphthalein method) as well as the non-destructive one like the Impact-Echo or the Ultrasound time passage measurement. The combination of these techniques allows to determine and evaluate the progress of carbonation without the destructive testing of the samples which is necessary for the real applications of these materials.

Diagnostic of Loose Parts Event in Water Chamber of Steam Generator

During the hot performance test in a nuclear power plant, the alarm event of the loose parts of the steam generator occurred. In order to explore the alarm cause for the loose parts and evaluate the damage of the equipment, it is necessary to confirm the loose parts in time. By establishing the diagnosis and analysis model of the loose parts, the original data of the loose event is analyzed in detail, and the propagation speed of the loose signal, the quality and energy of the loose parts are estimated. Finally, the harmfulness of the loose alarm event is evaluated. The results show that the loose part in the steam generator is a moving metal part, which is a loose part of the internal structure of the reactor. The impact frequency of the loose part is 8700~9300 Hz, the peak range of impact acceleration is 3g~90g, the propagation group velocity of the loose signal is 3200~3300 m/s, and the mass of the loose part is estimated to be about 0.1 kg. The impact energy is 0.45~0.89 J. The diagnostic results of mass and energy are in good agreement with the actual situation, which shows that the proposed method is effective.

Research on pressure fluctuation of coolant with new type of boundary impedance at opening ports of water chamber

Liner cavitation erosion results from pressure fluctuation of water coolant around cylinders. The characteristics of acoustic field of water chamber are especially important to estimate the potential of liner cavitation. The specialty of water chamber geometry requires a new impedance model of the opening ports, which was simulated by combining a one dimensional sound pipe with piston sound source at infinite plate. The validity of the proposed impedance model has been confirmed by the comparison of attenuation ratio with experiment of actual cylinder block. By changing the clearance between piston and cylinder liner, the influence of cylinder vibration acceleration on water pressure variation was studied, which revealed that the larger clearance results in stronger pressure fluctuation dominated by certain frequencies components. The pressure fluctuation induced by the vibration of whole walls was compared with that induced by the vibration of one cylinder, it revealed that integration of liner and cylinder block may reduce the amplitude of pressure fluctuation.

PHYSIOLOGICAL PARAMETERS OF COTTON CULTIVARS IN WEST PAULISTA

Cotton varieties develop differently because they present different physiological characteristics in production environments. This study aimed to know the physiological characteristics of cotton. The experiment was carried out at the São Paulo Agribusiness Technology Agency (APTA), Alta Paulista region. The experimental design used was Entirely Randomized (DIC), with six cotton cultivars: IMA5801B2RF; FM975WS; TMG47B2RF; TMG81WS; FM944GL and IACRDN. Where the following physiological parameters were determined: Assimilation rate CO2, leaf transpiration, stomatal conductance, internal concentration of CO2 in the substomatic chamber and efficient use of water. The cotton varieties showed different physiological characteristics, the IMA5801B2RF variety had the lowest performance, which may reflect low productivity. Further physiological studies are needed to understand the Cotton varieties behavior

Dynamic Cutting Force and Stress Distribution of Carbide Insert during Asymmetric Milling of 508III Steel

In the milling process of water chamber head, the service life of cemented carbide inserts is low, and inserts are prone to premature breakage and impact fracture. Dynamic cutting force is one of the main factors leading to insert failure. In this paper, a dynamic cutting force model is established based on the characteristics of asymmetric milling of water chamber head and the characterization of cutting area variables. By comparing the calculated value with the experimental value, the model can describe the change of dynamic cutting force. Through theoretical analysis and insert stress distribution simulation, it is found that under the impact load of cutting force, the radial tension stress between the compression zone and the stretching zone is the main reason for the insert to crack and break. The results of this paper provide reference for the study of carbide insert failure.

An in depth experimental investigation into effects of incident wave characteristics front wall opening and PTO damping on the water column displacement and air differential pressure in an OWC chamber

Efficiency of an OWC depends solely on the water column heave motion and air pressure differential in the chamber. In this study, an extensive experimental campaign is conducted to investigate the displacement of water column surface (WCS) and chamber air pressure under different incident waves, chamber underwater opening heights and applied PTO dampings. It is found that, transmitted wave height (μ) and transmitted wave pressure (Pw) exponentially decay with the dimensionless wave frequency (Kh) irrespective of the relative opening (α) and orifice ratio (τ) (PTO damping), however, the decay rate slows down as the orifice ratio decreases. Effects of orifice ratio on μ and Pw heavily depend on the value of the Kh such that as Kh increases transmitted wave height, μ and pressure, Pw become less sensitive to variations in the orifice ratio, τ. Pw increase with the relative opening in a linear fashion but the upward trend declines for larger dimensionless wave frequencies. An almost perfect linear association is detected between transmitted wave height and pressure, and, captured wave length (δ) (incident wave length divided by chamber length). In the design stage, in order to prevent sloshing in the chamber δ smaller than approximately 4 should not be selected. Negative pressure peaks are always found to be larger than positive pressure peaks in magnitude. Further, a novel dimensionless pressure number NPR is proposed, which is found to be proportional to μ. Proportionality constant is also presented. Accordingly, prediction of μ or Pw yields the value of the other in an accurate manner. Despite the complex wave-energy conversion processes the most important aspects and the related parameters can be described using very accurate simple analytical models.

Occurrence and removal of drugs and endocrine disruptors in the Bolonha Water Treatment Plant in Belém/PA (Brazil).

This study aimed to investigate the occurrence of drugs and endocrine disrupters in water supplies and in water for human consumption. Twelve sampling campaigns were carried out during the rainy and dry season at four sampling points in the Bolonha Complex, in the city of Belém, northern region of Brazil: Bolonha reservoir (catchment) and Water Treatment Plant (WTP) Bolonha (filtered water chamber, treated water tank, and washing water from the filters). The determination of the compounds was performed by solid phase extraction followed by gas and liquid chromatography coupled to mass spectrometry. The results confirmed the anthropic influence that the reservoir and WTP-Bolonha have been suffering, as consequence of the discharge of domestic sewage in natura. Among 25 microcontaminants analyzed, 12 were quantified in raw water and 10 in treated water. The antiallergic Loratadine (LRT) was the contaminant that occurred most frequently in all sample points, having been poorly removed (median 12%) in the conventional treatment used. Losartana (LST), 4-octylphenol (4-OP), and Bisphenol A (BPA) also occurred very frequently in raw water with concentrations ranging from 3.7 to 194ng L-1. Although such contaminants occurred in treated water in concentrations varying from 4.0 to 135ng L-1, the estimated margin of exposure ranged from 55 to 3333 times which indicates low risk of human exposure to such contaminants through ingestion of treated water.

Real-time heart rate monitoring system for cardiotoxicity assessment of Daphnia magna using high-speed digital holographic microscopy

Machine vision techniques for monitoring heart rates in aquatic bioassays have been applied to cardiotoxicity assessment. However, the requisite large data sizes and long calculation times make long-term observations of heart rates difficult. In this study, we developed a real-time heart rate monitoring system for individual Daphnia magna in a water chamber mounter that immobilizes their movement in 100mL media. Heart rates are calculated from real-time, time-resolved relative phase information from digital holograms acquired with a 200 fps camera and parallel computation using a graphics processing unit. With this system, we monitored the real-time changes in the heart rates of individual D. magna specimens exposed to H2O2 as a positive control for reactive oxygen species (ROS) levels in an aquatic environment for 10h, a period long enough to observe dynamic heart rate responses to the mounting process and exposure and to establish heart rate trends. An additional group analysis was conducted to compare to conventional cardiotoxicity assessment, with results of both assessments showing that the heart rates reduced according to ROS level by H2O2 exposure concentration. Notably, the results of our real-time dynamic heart rate monitoring in aquatic conditions indicated that establishing a relaxation heart rate before measurements could improve the accuracy of toxicity assessment. It is believed that the system developed in this study, achieving the simultaneous measurement, analysis, and display of reconstructed results, will find wide application in other aquatic bioassays.

Results of experimental studies of changes in the level and heating of the main condensate in mixing-type LPH

In the thermal circuits of domestic steam turbines, mixing-type low-pressure heaters (LPH) with free-flow jet water distribution and counter-flow of water and steam are widely used. The choice of the counterflow variant of the media movement ensures the most efficient heat transfer. However, the technical problem of ensuring reliable operation of LPH in the entire range of design loads of TPP and NPP power units is still relevant.During the commissioning and operation of mixing-type LPH in 800÷1200 MW turbines of TPP and NPP, the presence of metal knocks in the zone of the check valve, hydraulic shocks in the heating section were revealed. A priori, these phenomena indicated design flaws in LPH or manufacturing defects in their production. Research carried out by NPO CKTI specialists showed that periodic hydraulic shocks in the heating section and metal knocks occur as a result of uneven distribution around the circumference of the main condensate and steam supply. This leads to a breakdown of the check valve and the destruction of perforated plates and off-design heating of water in the volume of the annular LPH water chamber. To clarify the causes of the damage, develop recommendations for the reconstruction of the apparatus and further account for the design, two series of experimental studies were carried out on mixing-type heaters of 800 MW turbine units PNSV-2000-1 and PNSV-2000-2 manufactured at PJSC Krasny Kotelshchik. The purpose of the experimental studies was to determine the change in the water level in the water chamber and the heating of the main condensate in the elements of the heating compartment during normal operation of the power unit at loads of 400÷850 MW. Based on the results of the research, the method for calculating the mixing-type LPH has been refined, taking into account the revealed non-uniformity of water heating in the water chamber, recommendations for their reconstruction have been developed and implemented.