Water-based Liquids Research Articles

N-halamine modified mesoporous silica coated cotton as multipurpose protective fibrous materials

N-halamine-containing mesoporous silica was prepared by treating the silica with (3-(trimethoxysilyl) propyl methacrylate), followed by grafting reaction of an N-halamine precursor, 3-(3′-hydroxypropyl)-5,5-dimethylhydantoin (APDMH). The resulting N-halamine mesoporous silica was applied to the surface of cotton by a coating process. The coated cotton showed good static and dynamic hydrophobic properties (static contact angle, 138.91°). After soaking in household bleach, N-halamines were formed on the coated fabric, which provided good antimicrobial properties against Gram-positive bacteria, Gram-negative bacteria, and fungi. The chlorinated sample inactivated 98.93% of Staphylococcus epidermidis, 97.83% of Escherichia coli O157:H7 and 82.24% of Candida albicans within 60 min, respectively. The coated and chlorinated samples showed high hydrophobicity toward other water-based liquids such as coffee, cola, green tea and milk. Further, the chlorinated fabric samples degraded ammonia in aqueous solutions. These attractive functions make the new N-halamine mesoporous silica coated cotton fabrics as an excellent candidate of multipurpose functional fibrous materials.

Comparison of oscillatory flow conditions in Newtonian and non-Newtonian fluids using PIV and high-speed image analysis

Oscillatory flow in pipelines is common in many industrial applications, including oil well drilling. An experimental investigation of oscillatory flow inside a vertical U-shaped circular pipe is presented in this paper to mimic the practical scenario takes place within a vertical oil well. Flow visualization was deployed to compare the velocity distributions in Newtonian (deionized water) and non-Newtonian fluid (a mixture of three water-based polymeric liquids). The experiments were performed in a 1.2 m high, 50 mm diameter transparent test section, at room temperature (21 °C) and atmospheric pressure.Particle image velocimetry (PIV) technique was used to obtain non-invasive instantaneous flow velocity profiles. Based on local velocities, the streamwise (axial) velocity component within the pipe across its diameter was determined and the cross-sectional average velocity together with the normalized axial velocity were also calculated. In addition, high-speed motion pictures were used to determine the displacement of the air-liquid interface at the top of the U-tube limb. This enabled comparison of the flow field with the overall volumetric oscillating flow. A piston was driven at harmonic motion via a gas buffer, to provide the driving force for the test fluids at four different low frequencies ranging from 0.1 to 0.75 Hz. Oscillatory Reynolds number (Reδ) based on Stokes layer thickness was used as the criteria for determining the specific flow regime. According to the literature, the critical value for the oscillating Reynolds number was considered to be 500, and with this as reference all the experimental cases were within the laminar regime. Eight different experimental cases were tested within the ranges of (4 <Reδ < 116) and Womersley number (3 <Wo < 55).At higher frequencies, the viscous effects for the Newtonian fluid are confined to the Stokes layer and the central core of the velocity profile is plug-type. At the same time, higher frequencies resulted with increased velocity amplitudes. The viscous resistance of the non-Newtonian fluid and the presence of shear layer contribute to an uneven velocity profile across the pipe cross-section. Cross-sectional average velocity provides a more complete picture of the kinematic structure of oscillating flow and its dynamic distribution across the cross-section. Non-Newtonian fluid tends to achieve higher normalized axial velocities compared to that for Newtonian fluid, which is more or less equals to unity.The study was partly motivated by challenges associated with operational procedures during drilling and maintenance of petroleum wells. Furthermore, this study is also part of a comprehensive study aimed at investigating the influence of low frequency oscillations on particle settling in non-Newtonian drilling fluids.

Experimental demonstration of imaging hidden objects in opaque liquid-based media by fusion of single-shot multiview polarized and unpolarized speckle images

Turbid water-based liquids are common scattering media within which imaging objects is challenging, since scattering particles of various origins and sizes may cause severe image degradation, resulting in poor object recovery and resolution. Therefore, counteracting the nontrivial effects of light scattering is a primary challenge, limiting the utility of optical imaging within liquid media. In this work, we sought to circumvent the optical degradation in turbid liquid media and to recover high-quality images of hidden objects by averaging polarized speckle images projected from several directions through a lens array. Inspired by astronomy imaging techniques, the averaging process utilized a Shift-and-Add (SAA) algorithm developed to reconstruct atmospherically-degraded solar images. Both linear and circular polarization strategies were then applied to further improve image reconstruction. Experiments were carried out using two targets, each having a distinct geometrical shape, embedded within turbid liquid media comprising a range of dilutions of commercially available cow's milk in seawater. The media were irradiated with a polarized laser beam, after which multiple polarized speckled images were captured with a CCD camera. Offline, images were first shifted to a common center and then fused, using the SAA algorithm, to yield reconstructed images of each hidden object. Quantitative image quality metrics, including SNR, entropy, and sharpness were applied to evaluate quality of the reconstructed images. The reconstructed images obtained demonstrate successful adaptation of our methodology for the identification of hidden objects within turbid media. To the best of our knowledge, this is the first report to demonstrate successful imaging of hidden object images within turbid liquid media by averaging multiple polarized speckle projections.

Polymer gel dosimeter with AQUAJOINT® as hydrogel matrix

We report a polymer gel dosimeter based on a new gel matrix (AQUAJOINT®) that is a thermo-irreversible hydrogel formed by mixing two types of water-based liquids at room temperature. Normoxic N-vinylpyrrolidone-based polymer gels were prepared with AQUAJOINT® instead of gelatin. This AQUAJOINT®-based gel dosimeter exhibits a 2.5-fold increase in sensitivity over a gelatin-based gel dosimeter and a linear dose–response in the dose range of 0–8 Gy. This gel has heat resistance in a jar and controlled gel properties such as viscoelastic and mechanical characters, which may be useful for deformable polymer gel dosimetry.

ELECTROMAGNETIC RESONANCE VIBROCAVITATOR

Резонансний електромагнітний віброкавітатор призначений для кавітаційного оброблення рідин на основі води. Ці кавітатори ефективні у використанні для очищення води басейнів аквапарків від біологічних забруднень, для покращення структури питної води. Резонансні електромагнітні віброкавітатори автори створили вперше, їх конструктивна будова захищена патентом на винахід. Конструкція цього вібраційного кавітатора доволі універсальна, що створює передумови для успішного використання її як для трубопроводів незначних перерізів у діапазоні від одного до трьох дюймів, так і для промислових труб водогонів діаметром до 250-300 мм. Особливо ефективним, на нашу думку, вібраційний кавітатор мав би виявитись для біологічного знезараження питної води. Простота його конструкції та обслуговування створюють передумови для вмонтовування кавітатора у трубопроводи перепомповування води в басейнах, аквапарках та водоймах громадського використання, де поряд із знезараженням води здійснюватиметься і її очищення. Внаслідок сплескування кавітаційних бульбашок тут утворюються активні хімічні речовини: гідроксильні радикали, озон, пероксид водню тощо. По суті, ця технологія є комбінованим способом очищувального впливу на воду. Основними вузлами цих кавітаторів є статор із електромагнітами, коливний якір із збурювачами кавітації та резонансна пружна система, що з'єднує якір із статором. Продуктивність кавітаційного оброблення води басейнів – 1,5-2,0 м3/год, ступінь очищення стоків молокопереробних підприємств – 97-98 % за продуктивності до 100 л/год. Продуктивність очищення стоків пивоваріння від дріжджів становить 200-250 дм3/год.

Quantitative detection of metallic traces in water-based liquids by microwave-assisted laser-induced breakdown spectroscopy

The enhancement of laser-induced breakdown spectroscopy (LIBS) assisted with microwave radiation is demonstrated for an aqueous solution of indium using the 451.13 nm emission line. Microwave power was delivered via a near-field applicator to the LIBS measurement volume where the indium aqueous solution was presented as a liquid jet. The microwave enhancement effect was observed to decrease with increasing laser pulse fluence at 532 nm resulting in a maximum emission intensity occurring at a laser pulse fluence of 85.2 J∙cm(-2), independent of the microwave power used. The detection limits of indium in an aqueous solution were determined to be 10.8 ± 0.7 and 124 ± 5 ppm for the cases of microwave enhanced and standard LIBS, respectively. The 11.5-fold detection limit enhancement obtained in the liquid phase is of the same order of magnitude as that reported for other elements in solid samples, but lower than that obtained in solid phase utilizing a similar experimental setup. This establishes microwave enhancement as an effective technique for the detection of metals in aqueous solutions. In addition, the temporal evolution of plasma emission intensity was investigated and was found to be qualitatively similar to that of plasma produced from solid phase samples, which reveals the same coupling mechanism between laser generated plasma and microwave radiation.

Potential Controlled Tribological Behavior of Water-Based Ionic Liquids

Increase of energy efficiency, reliability and durability of technical systems in combination with resource conservation using environmentally friendly water-based lubricants would be an overarching goal in all tribological applications. According to this aim the objective of this work is to investigate and identify new water-based lubricants containing ionic liquids (ILs) to reduce friction and wear. Therefore the tribological behavior of different water-based ionic liquid mixtures, compared with a standard water based cooling lubricant emulsion, was studied using a ball-on-disk test. A three electrode setup was used to analyze the influence of different electric potentials. The results show that friction and wear can be improved by using ionic liquid. In addition, the tribological behavior can be strongly influenced by electric potentials. As tribological mechanism the attraction of cations and the formation of a triboactive layer is assumed, due to charging of the surface.

Complex Permittivity of Water-Based Liquids for Liquid Antennas

Liquid antennas have attracted increasing attention recently. In this letter, a promising candidate for liquid antennas, namely water with propylene glycol (PG), is investigated using both measurement and numerical simulation approaches. The nonlinear least-squares fitting routines are employed to derive new formulas for the approximation of the complex permittivity of the liquid. The permittivity of this liquid at various temperatures and substance concentration levels are investigated. The results are obtained and compared to the measurement. Good agreements are obtained, and new comprehensive knowledge is gained. In particular, the permittivity of water with PG at various conditions is reported for the first time. These results should be very useful for a range of applications such as liquid antenna designs.

Solid State Physics View of Liquid State Chemistry — Electrical conduction in pure water

Engineering characterization of water has produced huge varieties of materials with special properties to meet human needs. Equilibrium properties of water-based liquids are well understood via localized atomic and molecular orbital theories. However, the mechanism of electrical conductivity of pure water has proven elusive. We show here it is trapping limited drift of positive and negative quasi-protons (or protons and proton-vacancies) on the extended water lattice, which is accounted for by the long-range correlation inherent in the Fermion (electrons and protons) and Boson (phonons) energy band theory of quasi-particles in solids, with vigorous adherence to equilibrium and nonequilibrium states.

Bioavailability of Oil-Based and β -Lactoglobulin-Complexed Vitamin A in a Rat Model.

β-Lactoglobulin is capable of binding fat-soluble compounds including vitamin A palmitate and is suggested to specifically enhance intestinal uptake of retinol. In this study, bioavailability of a vitamin-A-retinyl palmitate complex in skim milk and in water-based liquids was investigated in vitamin-A-depleted rats. First, rats were fed a vitamin-A-free pellet diet for 6 wk and were thereafter gavage-fed with vitamin A in oil, vitamin-A-β-lactoglobulin complex, vitamin A in oil + skim milk, and vitamin-A-β-lactoglobulin + skim milk for 2 wk and 42 wk. Vitamin A repletion, as judged by vitamin A accumulation in serum and liver, occurred in all the treatments. Vitamin-A-β-lactoglobulin complex treatments had statistical equivalence with oil-based vitamin A treatments. In a second experiment, vitamin-A-depleted rats were fed UHT-processed skim milk fortified with either oil-based or freeze-dried β-lactoglobulin-complexed retinyl palmitate. Liver and serum vitamin A were analyzed by HPLC to indicate vitamin A status in the rats. Results showed no significant difference in bioavailability of retinyl palmitate from milk made with either regular oil-based or β-lactoglobulin-complexed fortifiers. The vitamin-A-β-lactoglobulin complex, being water soluble, may be useful for fortification of nonfat products.

Quantitative analysis of metallic traces in water-based liquids by UV-IR double-pulse laser-induced breakdown spectroscopy

Double-pulse laser-induced breakdown spectroscopy (DP-LIBS) was performed for quantitative analysis of three metallic trace elements: Fe, Pb and Au in aqueous solutions. The plasma was generated using a UV (266 nm) frequency-quadrupled Q-switched Nd:YAG laser (7 ns) and then reheated by a 1064 nm Q-switched Nd:YAG laser (7 ns) in a quasi-collinear geometrical configuration. In order to improve the reproducibility of LIBS measurements, a circulation cell was used, providing a reproducibility of about 4% with a laser repetition rate of 0.3 Hz. The influence of the inter-pulse delay and the fluence of the second laser pulse on the signal-to-noise ratio (SNR) for the analytical lines was investigated and optimized. Analytical figures of merit of DP-LIBS and conventional single-pulse LIBS (SP-LIBS) were evaluated by establishing the calibration curves for the Fe I 358.12 nm, Pb I 405.78 nm and Au I 267.60 nm lines. The signal was greatly enhanced in DP-LIBS while the noise level did not vary as much. An improvement of the relative limit of detection of about 10 was achieved using DP-LIBS when compared to UV SP-LIBS in all cases. Measurement of the electron density as a function of time indicates that the plasma plume lifetime is longer in DP-LIBS. Similar trends in the excitation temperature were not observed for reasons that we attribute to larger uncertainties related to the Boltzmann plot method.

The Effects of Various Adhesives on Dye and Pigment-based Inkjet and Dye Sublimation Prints

This study explored the reactivity of various adhesives on dye and pigment inkjet and dye sublimation prints. Consumers have reported adverse experiences including colorant bleed and yellowing in areas that were in contact with mounting adhesives. An accelerated test was conducted to study chemical interactions that might result in colorant fade, colorant bleed, yellowing, adhesive transfer or physical distortions of the digital prints. Fourteen different adhesives were applied to fine art, polymer and microporous photo papers, inkjet-sized and plain document papers, and dye sublimation paper. Images were printed on the photo and document papers using various inkjet printers and on the dye sublimation paper using a dye sublimation printer. The types of adhesives tested included water-based liquids, pressure sensitive tapes, laminating films, self-sticking notes and spray photo-mounting adhesives. The test combinations included prints without adhesives, prints with adhesives kept at room conditions (21&#xB0;C and 50% RH) and prints with adhesives incubated at 70&#xB0;C and 50% RH for 84 days as specified by ISO 18932 Imaging materials&#x2014;Adhesive mounting systems&#x2014;Specifications. This study provides a better understanding of the vulnerability of inkjet and dye sublimation materials to certain types of adhesives. The results showed colorant bleed, yellowing, adhesive transfer and physical distortions of the digitally printed materials can be caused by some of the adhesives tested in this study.

Magnetization Control of Magnetic Liquids for Sink-Float Separations

The cut-density of sink-float separations with water-based magnetic liquids linearly depends on the magnetization of the process liquid. The control of the magnetization of the liquid, by means of measurement followed by extraction of water from the process liquid by membranes or mixing with water or concentrated magnetic liquid, is therefore a critical part of the technology. A potential problem with mixing-in concentrated magnetic liquid is that the process liquid may become inhomogeneous and will segregate in the magnetic field region. Mixing experiments for various scenarios were carried out on a simplified experimental process line and magnetization levels were compared with theoretical models. The results show as process liquid segregation, due to incomplete mixing, can be avoided for all conceivable control strategies by using static mixers. A measurement tool based on a magneto-gravimetric principle was shown to have sufficient sensitivity to detect and control fluctuations of the magnetization of such a fluid in an industrial environment.

Gas-Discharge Plasma-Assisted Functionalization of Titanium Implant Surfaces

A crucial factor for in-growth of metallic implants in the bone stock is the rapid cellular acceptance whilst prevention of bacterial adhesion on the surface. Such contradictorily adhesion events could be triggered by surface properties. There already exists fundamental knowledge about the influence of physicochemical surface properties like roughness, titanium dioxide modifications, cleanness, and (mainly ceramic) coatings on cell and microbial behavior in vitro and in vivo. The titanium surface can be equipped with antimicrobial properties by plasma-based copper implantation, which allows the release and generation of small concentrations of copper ions during contact with water-based biological liquids. Additionally, the titanium surface was equipped with amino groups by the deposition of an ultrathin plasma polymer. This coating on the one hand does not significantly reduce the generation of copper ions, and on the other hand improves the adhesion and spreading of osteoblast cells. The process development was accompanied by physicochemical surface analyses like XPS, FTIR, contact angle, SEM, and AFM. Very thin modified layers were created, which are resistant to hydrolysis and delamination. These titanium surface functionalizations were found to have either an antimicrobial activity or cell-adhesive properties. Intramuscular implantation of titanium samples coated with the cell-adhesive plasma polymer in rats revealed a reduced inflammation reaction compared to uncoated titanium.

A TDR Method for Real-Time Monitoring of Liquids

Time-domain-reflectometry (TDR) measurements, which were originally used to locate and diagnose faults in transmission lines, have been widely applied in geology and soil science for accurate and flexible measurements of soil moisture and water content. Furthermore, the most attractive advantages of TDR rely on the possible determination of the spatial location and nature of various objects, both in real time and with a nondestructive approach. This makes the TDR technique an appealing candidate for a variety of environmental and industrial applications. Although the TDR instruments are commonly used to date, particularly for the aforementioned purposes, the state of the art is rather lacking in liquid-monitoring applications. This paper describes how the suitable combination of TDR detecting functionalities can lead to a simultaneous monitoring of quantitative and qualitative properties of liquid samples. In fact, the proposed TDR method allows, in one shot, the measurement of liquid levels, the determination of multiple interfaces in layered media, and the evaluation of dielectric properties such as dielectric permittivity or electrical conductivity. Some applications to real cases are proposed, which are referred to petrol-chemical mixtures or water-based liquids, thus validating the approach on a wide range of materials.

Tribological aspects of the use of water-based liquids in the hydraulic systems of vehicles

Tribological aspects of the use of water-based liquids in the hydraulic systems of vehicles

Simultaneous measurement of dielectric properties and levels of liquids using a TDR method

Several monitoring methods, in the recent years, involved microwave/radio frequency (RF) reflectometry techniques, particularly in remote sensing, environmental and industrial application fields. The main advantages using reflectometry are due to its relevant performance characteristics, in terms of high flexibility, high sensitivity and large application conditions. Furthermore, the time domain reflectometry (TDR) presents some attractive advantages, related to the possible determination of the spatial location and nature of various objects, in real-time and with a non-destructive approach. This makes the TDR technique an appealing candidate for a variety of environmental and industrial applications. Although TDR instruments are commonly used today, particularly for the above mentioned purposes, the state of the art is rather lacking in liquid monitoring applications. In this paper we demonstrate that a suitable combination of TDR detecting functionalities, in terms of spatial localization, dielectric properties estimation and coaxial probe performance characteristics, leads to an enhanced quantitative and qualitative monitoring method. Really, in one shot, the analysis of TDR data allows the measurement of liquid levels, the determination of multiple interfaces in layered media, as well as the evaluation of dielectric properties, such as dielectric permittivity or electrical conductivity. Moreover, some applications to real cases are proposed, referred to petrol–chemical mixtures or water-based liquids, thus validating the approach on a wide range of materials.

Do Baby-Friendly Hospitals Influence Breastfeeding Duration on a National Level?

Do Baby-Friendly Hospitals Influence Breastfeeding Duration on a National Level?

Micro-electromechanical systems based on 3C-SiC/Si heterostructures

Wide band gap semiconductors like SiC are excellent materials for high temperature, high frequency and high power applications. Furthermore, the properties of SiC fulfil the requirements for modern applications in micro-sensors, micro-actuators as well as in micro- and nano-electromechanical systems (MEMS and NEMS). Novel applications of SiC/Si based MEMS and NEMS are dosing and sensor systems for micro- and nano-fluidic systems, e.g. for fast and reliable biomedical testing and analysis. We have developed a technology for processing SiC/Si-based MEMS and NEMS. A micro dosing head for pulmonary amounts of water-based liquids was realized. This dosing head consist of parallel operating multi micro pipes running at a defined pressure. Furthermore, we used 3C-SiC/Si heterostructures to process resonator bars having geometries in the μm range and a thickness of 250 nm. These bars open the possibility to evaluate the viscosity of water nano-droplets, to measure the mass of biomolecules, especially proteins, positioned on the bars. The used 3C-SiC layers were grown by a special chemical vapor deposition under ultra high vacuum (UHVCVD) conditions. This kind of deposition process allows us to grow the cubic silicon carbide polytype at relatively low temperature (below 900 °C). Such growth conditions allow reducing the internal stress of the grown monocrystalline layers, which is an important precondition for fabrication of reliable MEMS and NEMS structures based on silicon carbide.

In situ chemical experiments in carbon nanotubes

Understanding the interaction of water-based liquids with carbon at the nanoscale is very important for exploring the potential of carbon nanotubes in nanofluidic chips, probes, and capsules for drug delivery. By using hydrothermal synthesis, we produced closed hydrophilic multiwall carbon nanotubes filled with aqueous fluid. They allow for the first time high-resolution in situ studies of an interface between fluid and carbon in TEM. Strong interaction between the liquid and walls, intercalation of nanotubes with O–H species and dissolution of walls upon heating have been demonstrated. Thermodynamics simulation was used to explain the interaction of nanotubes with fluid.