Test Liquid Research Articles

Application of Carboxymethyl Chitosan on Adsorbent Detoxification of Paralytic Shellfish Poisoning Toxins from <i>Chlamys nobilis</i>

This study investigates the effectiveness of adding carboxymethyl chitosan during steam cooking as an adsorbent for detoxifying paralytic shellfish poisoning toxins (PSP toxins) in the scallop Chlamys nobilis. Toxin analysis using a mouse bioassay test and hydrophilic interaction liquid chromatography–tandem mass spectrometry method (LC–MS) showed that most of the PSP toxins (>80%) were contained in the visceral compartment of the raw scallops. Overall, 82.2Mu/100g of PSP toxins were released from scallop tissues during steaming. The toxicity of the soup steamed with 0.1%, 0.3%, 0.6%, 1.0% and 1.5% carboxymethyl chitosan decreased the toxin content by 35.6%, 44%, 48.4%, 53.3% and 56.9% (p<0.005), respectively. The relative PSP toxin content in the raw adductor muscle was comparable to those after steaming or steaming with carboxymethyl chitosan (p > 0.05).The PSP toxin concentrations in the adductor muscles, gills + mantle and visceral compartments steamed with 0.1%, 0.3%, 0.6%, 1% and 1.5% carboxymethyl chitosan were not significantly different from those in the corresponding raw samples. The LC–MS analysis showed that the adsorbance of carboxymethyl chitosan for each of the PSP toxins was positive correlation with concentration, although the uptake efficiency of each toxin was different. The reduction in toxin content of all analyzed toxins reached 45.6%, 30.2%, 44.5%, 55.9% and 37.6% under the corresponding carboxymethyl chitosan concentrationsis.

Low in vitro third-body wear on total hip prostheses induced by calcium sulphate used for local antibiotic therapy.

In case of implant associated infection, implant preservation is associated with high failure rates. Therefore, a removal or exchange of the implant is most often mandatory for treatment success. Alternatively, under certain conditions, local antibiotic delivery can be applied - preserving the implant, using for example calcium sulphate as a resorbable carrier. In this work, third-body wear on total hip prostheses caused by calcium sulphate particles was tested in a hip simulator. Inlays made of ultra-high-molecular-weight polyethylene (UHMWPE) and cross-linked polyethylene (XLPE) against 28 mm CoCrMo heads and 36 mm alumina pairings were tested in triplicate, both with and without calcium sulphate particles in the test liquid. Neither the alumina articulations nor the CoCrMo heads were affected by the calcium sulphate particles since calcium sulphate is a relatively soft material. The polyethylene inlays showed 39-89 % higher wear during exposure compared to references, but wear returned to normal when no more particles were added. Thus, calcium sulphate might be used as antibiotic carrier even in the presence of total hip prostheses without fearing excessive third-body wear.

Evaluation of roughness, wettability, and morphology of an yttria-stabilized tetragonal zirconia polycrystal ceramic after different airborne-particle abrasion protocols

Airborne-particle abrasion is an effective method of roughening a zirconia surface and promoting micromechanical interlocks with luting cements. However, the effect of different airborne-particle abrasion protocols on the micromechanical retention mechanism has been poorly investigated. The purpose of the study was to evaluate the effect of airborne-particle abrasion protocols on the surface roughness, wettability, and morphology of an yttria-stabilized tetragonal zirconia polycrystal ceramic. A total of 140 zirconia specimens (14 × 14 × 1.4 mm) were made from Lava and divided into 7 groups. Their surfaces were treated as follows (n = 20): as-sintered (control); airborne-particle abraded with 50-μm Al2O3 particles; 120-μm Al2O3 particles; 250-μm Al2O3 particles; 30-μm silica-coated Al2O3 particles (Rocatec Soft); 110-μm silica-coated Al2O3 particles (Rocatec Plus); and 120-μm Al2O3 particles followed by Rocatec Plus. The surface roughness (Ra) and wettability analyses were performed on the same specimens of each group. The test liquid used for the wettability analysis was the silane RelyX Ceramic Primer. Two additional specimens (6.0 × 6.0 × 1.0 mm) per group were prepared to evaluate the surface morphology with scanning electron microscopy. The roughness (Ra) data were analyzed by 1-way ANOVA and the Dunnett C test (α = .05), and the wettability data with 1-way ANOVA (α = .05). The Spearman correlation analysis was applied to test for a possible correlation between roughness and wettability. The control group (0.35 μm) exhibited the lowest mean roughness value (Ra), which was followed by Rocatec Soft (0.40 μm), 50-μm Al2O3 particles (0.52 μm), Rocatec Plus (0.69 μm), 120-μm Al2O3 particles (0.80 μm)/120-μm Al2O3 particles + Rocatec Plus (0.79 μm), and 250-μm Al2O3 particles (1.13 μm). No significant difference was found among the groups concerning wettability. No correlation (rs = -0.09; P = .27) was found between the 2 dependent variables. The scanning electron microscopy analysis indicated that the different airborne-particle abrasion protocols produced differences in the morphologic patterns. Although roughness and morphology of the zirconia surface varied according to the airborne-particle abrasion protocol, no close relationship was found between them. The roughness increase seemed to have followed the size of the particles.

Carbon capture and sequestration: an exploratory inhalation toxicity assessment of amine-trapping solvents and their degradation products.

Carbon dioxide (CO2) absorption with aqueous amine solvents is a method of carbon capture and sequestration (CCS) from flue gases. One concern is the possible release of amine solvents and degradation products into the atmosphere, warranting evaluation of potential pulmonary effects from inhalation. The CCS amines monoethanolamine (MEA), methyldiethanolamine (MDEA), and piperazine (PIP) underwent oxidative and CO2-mediated degradation for 75 days. C57bl/6N mice were exposed for 7 days by inhalation of 25 ppm neat amine or equivalant concentration in the degraded mixture. The aqueous solutions were nebulized to create the inhalation atmospheres. Pulmonary response was measured by changes in inflammatory cells in bronchoalveolar lavage fluid and cytokine expression in lung tissue. Ames mutagenicity and CHO-K1 micronucleus assays were applied to assess genotoxicity. Chemical analysis of the test atmosphere and liquid revealed complex mixtures, including acids, aldehydes, and other compounds. Exposure to oxidatively degraded MEA increased (p < 0.05) total cells, neutrophils, and lymphocytes compared to control mice and caused inflammatory cytokine expression (statistical increase at p < 0.05). MEA and CO2-degraded MEA were the only atmospheres to show statistical (p < 0.05) increase in oxidative stress. CO2 degradation resulted in a different composition, less degradation, and lower observed toxicity (less magnitude and number of effects) with no genotoxicity. Overall, oxidative degradation of the amines studied resulted in enhanced toxicity (increased magnitude and number of effects) compared to the neat chemicals.

Evapoporometry determination of pore-size distribution and pore fouling of hollow fiber membranes

Hollow fiber (HF) membranes are used in many applications for which characterization of the pore-size distribution (PSD) is necessary. Current techniques for determining the PSD require relatively expensive dedicated equipment. Moreover, most techniques are not applicable for characterization of fouled membranes. Evapoporometry (EP) is a novel characterization technique based on vapor-pressure depression that can detect the full spectrum of pore sizes in ultrafiltration (UF) membranes. In prior studies EP was used to determine the PSD of only flat sheet membranes using just isopropyl alcohol (IPA) as the volatile wetting test liquid. Here it is extended to HF membranes using both IPA and water as the test liquids. The average pore diameter of polyvinylidene fluoride (PVDF) HF membranes using IPA and water as the test liquids was 30.2±1.4nm and 27.4±2.0nm, respectively. The average pore diameter using IPA and water for polyacrylonitrile (PAN) HF membranes was 11.8±1.0nm and 12.1±2.8nm, respectively. Liquid displacement porometry (LDP) gave a markedly smaller average pore diameter of 20.7±3.8nm for the PVDF membranes compared to evaluating the pore diameter with EP owing to compaction under displacement pressures as high as 6MPa. LDP gave a substantially larger average pore diameter of 26.5±1.0nm for the PAN membranes compared to evaluating the pore diameter with EP owing to its inability to characterize pores smaller than 14nm. EP characterization of the PSD before and after fouling the PVDF membrane with humic acid and bentonite showed a 35% reduction in the effective average pore diameter owing to internal pore fouling.

Tölgy fafelületek néhány paraméterének vizsgálata megmunkálás után

&lt;p class="p1"&gt;&lt;span class="s1"&gt;Faanyagok ragasztásakor és felületkezelésekor nagyon fontos szerep jut a nedvesítésnek. A faanyag nedvesíthetősége egyenes arányban áll a felületi feszültséggel, &lt;/span&gt;azaz minél nagyobb az anyag felületi feszültsége a folyadékhoz képest, annál jobban nedvesíti a folyadék a felületet. Jelen tanulmányban a fa felületi érdességének nedvesítésre, felületi feszültségre gyakorolt hatását vizsgáltuk, meghatározott, a gyakorlat számára is releváns érdesség tartományban. A kocsánytalan tölgy (&lt;em&gt;Quercus petraea&lt;/em&gt;&lt;span class="s1"&gt;) alapanyagot három különböző szemcsefinomságú (60, 80, 100) csiszolópapírral csiszoltunk, majd a mintatesteken felületi érdesség és felületi feszültség méréseket végeztünk. &lt;/span&gt;Míg a vizsgált felületek érdességében szignifikáns különbségeket tapasztaltunk, addig a felületi feszültség értékei egymáshoz igen közel állnak, a mért adatokban nem volt szignifikáns különbség. Feltételezzük, hogy az érdességnek ebben a tartományában az 5 µl &lt;span class="s1"&gt;űrtartalmú vízcsepp a lokális érdesség durva felszínű viszonyai közepette túl &lt;/span&gt;nagy ahhoz, hogy 2-3-4 egymás mellé sorolódó érdesség csúcs adta érdességet kimutasson.&lt;/p&gt;

Method for digital measurement of phase-frequency characteristics for a fixed-length ultrasonic spectrometer

One of the most accurate methods for measuring the compressibility of liquids is resonance measurement of sound velocity in a fixed-length interferometer. This method combines high sensitivity, accuracy, and small sample volume of the test liquid. The measuring principle is to study the resonance properties of a composite resonator that contains a test liquid sample. Ealier, the phase-locked loop (PLL) scheme was used for this. In this paper, we propose an alternative measurement scheme based on digital analysis of harmonic signals, describe the implementation of this scheme using commercially available data acquisition modules, and give examples of test measurements with accuracy evaluations of the results.

Chemical Sensing via Chemotaxis of &lt;i&gt;Euglena gracilis&lt;/i&gt; Confined in an Isolated Micro-Aquarium

On-chip cytotoxicity sensing for liquid substances was investigated by using the microbial chemotaxis of Euglena gracilis. The Euglena cells were confined in a closed-type micro-aquarium in a PDMS microchip, and the micro-aquarium was isolated from two microchannels to flow test and reference liquid substances. Small molecules of liquids permeated into PDMS and diffused into the water in the micro-aquarium, and thus, the chemical concentration gradient of test liquids was built in the micro-aquarium. The negative chemotactic movements of Euglena cells were observed for ethanol down to 0.5% within 2-5 min after the injection of diluted ethanol into one of the separated microchannels (counter reference = pure water). On the other hand, when 0.5% H2O2 was introduced as a test liquid (counter reference = pure water), the Euglena cells fell into continuous rotation instead of single step turning and/or straight forward swimming. As a result, total swimming activity in the micro-aquarium decreased even after H2O2 flow was switched back to water. The observation shows that the types of cytotoxic effects can be identified through the cell movement analysis.

Pharmacokinetic-pharmacodynamic model of the antihypertensive interaction between telmisartan and hydrochlorothiazide in spontaneously hypertensive rats

The goal of this study was to establish an integrated indirect response pharmacokinetic-pharmacodynamic model between telmisartan and hydrochlorothiazide to describe the antihypertensive interaction of these two drugs in spontaneously hypertensive rats. The blood pressure and plasma concentrations were measured by the tail-cuff test and high performance liquid chromatography-mass spectrometry, respectively, in spontaneously hypertensive rats. The current pharmacokinetic-pharmacodynamic model was based on the non-competitive pharmacodynamic interaction of two drugs acting on different physiological processes. This model was able to acquire the temporal changes in drug concentration and blood pressure after administration of telmisartan or hydrochlorothiazide. The noncompetitive pharmacodynamic interaction assumed that the decreased blood pressure was attributed to the inhibitory function of telmisartan and stimulatory function of hydrochlorothiazide after administration of these two drugs. There was no significant pharmacokinetic change of telmisartan and hydrochlorothiazide in the different groups tested. The model predicted a synergistic pharmacodynamic interaction when telmisartan was administered in combination with hydrochlorothiazide, which was notably stronger than if the effects were additive. The results showed that the presented pharmacokinetic-pharmacodynamic model was suitable for describing the antihypertensive interaction between telmisartan and hydrochlorothiazide.

Heat Transfer and Pressure Drop Studies Through a Square Duct Fitted With Increasing and Decreasing Order of Twisted Tape

Experimental investigation of heat transfer and friction factor characteristics of a square duct fitted with an increasing and decreasing order of twist ratio set have been studied under a nearly uniform wall temperature condition for laminar flow using water as test liquid. The Reynolds number was varied from 100 to 2100. Cold water flows through the inner square duct, and hot water passes through the circular annulus, in countercurrent fashion. There is not much change in the magnitude of heat transfer coefficient enhancement with increasing twist ratio and with decreasing twist ratio set, as the intensity of swirl generated at the inlet or at the outlet in the order of increasing twist ratio or decreasing twist ratio is the same in both the cases. The experimental results show that Nusselt numbers were found to be 1.33–4.27 and 0.9–3.46 times the plain square duct forced convection values based on constant flow rate and constant pumping power criteria, for increasing and decreasing order of twist ratio sets, respectively.

Research on Mechanism of Fluid Flow Characteristics in a Stirred Tank with Stirrer Composed of Perturbed Six-Bent-Bladed Turbine

The power consumption and pressure distribution of Newtonian fluid and pseudoplastic fluid in a stirred tank with stirrer composed of perturbed six-bent-bladed turbine (6PBT) were calculated by CFD combined with laminar viscosity model. The test liquid used were glycerine and 1.25% (wt) xanthan gum solution, a pseudoplastic fluid with a yield stress. Compared with the stirrer composed of six-bent-bladed turbine (6BT), the effects of the 6PBT impeller on fluid pressure distribution were extensively analyzed, and the Coriolis force role of strengthening swirling motion and efficient agitation mechanism of 6PBT impeller were made a thorough inquiry, respectively. Results show that 6PBT impeller can lead to an energy saving effect as the increasing speed, and generate a larger low pressure region in flow field at the same time, so this is more beneficial to the whole circulation. Moreover, the stronger swirling motion may emerge in stirred tank with 6PBT impeller under the action of Coriolis force, which is exceedingly advantageous to promotion of mixing efficiency. As a result, 6PBT impeller is found to have a obvious superiority on mixing process of pseudoplastic fluid. The research results provide valuable references and instructions for the development of new type impeller.

New experimental system for high pressure and high temperature flashing evaporation experiments

Considering the high pressure and high temperature flash evaporation appearing frequently in industry, we design and build an experimental system to explore the flash evaporation under high pressure and high temperature that has not been studied very well. This system includes a very large chamber that provides enough space for the flash wave to spread and also allows two large visualization windows on it, so more image information can be obtained. The chamber is designed to have the cylindrical inner shape to satisfy the strength requirements while the outer shape is cubic. Of particular feature is the boiler as the heat system, which is used in our system to heat the water in the chamber. The Fiber Bragg Grating sensors are used to measure the temperature of the test liquid (water) and a high speed CCD digital camera is set in front of the visualization window to record the pictures of the flash phenomenon. Finally we carried out a test to verify this system.

Subcooled pool film boiling heat transfer from small horizontal cylinders at near-critical pressures

Experimental results for subcooled pool film boiling on small horizontal cylinders at near-critical pressures are presented. Experiments were performed with CO2 was the test liquid and platinum wires (25.4, 76.2 and 100μm diameter, D) as the test heaters. The pressure (P), liquid subcooling (ΔTsub) and bulk liquid temperature (Tb) were varied parametrically. For the range of parameters investigated, the heat transfer coefficient (h) was found to be proportional to D−0.5. Because the dependence of h on D varies, a criterion has been developed to predict a priori what this dependence would be any given situation. Subcooled pool film boiling heat transfer coefficient data have been correlated. The correlation developed predicts almost all the experimental data from the current study to within ±10%. The strength of the new correlation is that it is applicable to a much wider range of experimental conditions (including level of gravity) and fluids as demonstrated by the fact that it predicts all of the data reported in the literature to within ±20%. Visual observations during experiments showed that the transitions in film boiling patterns are a function of the dimensionless cylinder diameter.

Wettability characterization and adhesion enhancement of arc-treated surface of aluminum alloys

The aim of this study is to determine the wettability-enhancing effects of an atmospheric pressure, direct current (DC) plasma arc discharge on the surface of aluminum alloys. Wettability is a critical factor in engineering applications such as biomedical implants, painting, and adhesive bonding. For example, in the realm of adhesive bonding, greater wettability improves a metal substrate's attraction to an adhesive material and results in a higher bond quality. In this study, the contact angle was determined and compared as a measure of the wettability using two different techniques: the sessile drop and the ballistic deposition with water as a test liquid. The effect of different arc discharge process parameters on the wettability, including arc current and plasma torch velocity, was studied. A two-dimensional finite element analysis based on the volume-of-fluid model was carried out to explore the behavior of droplet (e.g., spreading and stabilization) on an ideal surface. Additionally, the values of the dynamic receding contact angle were measured through the simulation by applying the tilted plate method and considering the surface roughness to compare the results with the values obtained from the ballistic deposition method. Studying the wettability alteration of the surface of aluminum alloys subjected to the arc treatment revealed the wettability reduction over time. Additionally, it was found that there was a linear correlation between the contact angle value and the strength of adhesively bonded joints using two structural adhesives. The results of this study in the wettability modification of aluminum subjected to the arc treatment and wettability alteration of the treated substrate over time may be used as a quality assurance tool to design the production process and achieve the desired quality and strength in adhesively bonded joints.

Liquid volume measurements in the cavity formed by single droplet impacts into a thin, static liquid film

The time variation of the liquid volume beneath the cavity formed by the impact of a single droplet into a static liquid film (termed the “sub-cavity volume”) over an unheated, horizontal surface has been measured for the first time, using water as the test liquid. Droplet Weber numbers, Reynolds numbers, and initial liquid film thickness-to-drop diameter ratios were studied that are representative of the impact conditions that are expected for typical sprays. The thin liquid film thickness beneath the droplet impact cavity (the “sub-cavity liquid film thickness”) was measured using a non-contacting optical thickness sensor, as a function of both time and radial distance away from the impact cavity centerline. These data have been numerically integrated to determine the time variation of the sub-cavity liquid volume. The measured liquid film thickness decreases away from the cavity centerline in the immediate vicinity of the inner crown wall. The sub-cavity volume is typically between 30% and 35% of the droplet volume, and remains near this plateau value over much of the cavity lifetime. The measured sub-cavity liquid volume and cavity lifetime are used for one example case to demonstrate the predicted values of both the local heat flux averaged over an individual cavity, and the overall heater average heat flux, that would be required to dry out the cavity prior to cavity fill in. The computed average heat flux value for this first example case, on the order of 4–6MW/m2, is the same order of magnitude as the range of measured overall critical heat flux values referenced in the spray cooling literature.

EXPERIMENTAL STUDY OF BUBBLE DYNAMICS DURING NUCLEATE FLOW BOILING ON HORIZONTAL AND VERTICAL SURFACES

Knowledge of the physical mechanisms governing bubble dynamics and two-phase heat transfer is required to develop mechanistic models and to accurately predict and scale the performance of two-phase systems in reduced gravity environments. To better understand the effect of the magnitude of gravity on flow boiling, especially the dynamics of single bubbles under different levels of bulk liquid velocity, surface orientation at earth normal gravity and contact angle effects were studied in this work. A microfabricated nucleation site (10 mm in diameter) at the center of a flat heating surface was used to generate bubbles. Silicon and aluminum were used as substrate materials, with static contact angles of 56° and 19°, respectively, and water as the test liquid. Bulk liquid velocities ranged from 0 to 0.25 m/s, for horizontal and vertical surface orientations, in upflow conditions. Bulk liquid temperature was set close to saturation temperature, with bulk liquid subcooling less than 1°C, and wall superheat was maintained between 5.0°C and 6.0°C. The experimental results for bubble growth, departure diameter and time for departure, bubble sliding distance and velocity, bubble lift-off diameter and time for lift-off, and bubble base diameter are reported for vertical and horizontal orientations, as the system variables were varied parametrically. It is found that irrespective of orientation and contact angle, departure and lift-off diameters decrease with increase in bulk liquid velocity. At a given velocity, departure diameter decreases with increase in the component of gravity parallel to the heater surface. For a given bulk liquid velocity, increase in contact angle results in increase in bubble departure and lift-off diameters, for all orientations. For given conditions, bubble lift-off diameter increases with decrease in the component of gravity normal to the heater surface. The effect of gravity on lift-off diameter is reduced at high liquid bulk velocities. For given orientation and flow velocity, sliding distance decreases monotonically with decrease in contact angle. The bubble velocity at lift-off increases with increase in flow velocity and increase in the component of gravity parallel to heater surface.

S1110503 噴流キャビテーションによる非衝突面の壊食 : 円筒状試験片による実験([S111-05]第20回卒業研究コンテスト(5),機素潤滑設計部門)

Experiment on cavitation erosion caused by a cavitating oil jet was performed. The mineral oil type hydraulic fluid with VG 32 was used as the test liquid and the oil temperature was kept at 40℃. The cylindrical specimens with the length of 20 mm, the outer diameter of 20 mm, and the inner diameter of 5, 10, and 15 mm were prepared. The inner diameter of the test chamber was 170 mm, the diameter of the nozzle was 1 mm, the upstream absolute pressure was 10.1 MPa, and the cavitation number defined by the ratio of the downstream pressure to the upstream pressure was 0.02. The stand-off distance was varied from 10 to 25 mm by 2.5 mm. The specimen was eroded partially on the inner wall at a location from the downstream-side end of the specimens. The eroded location was slightly moved to the upstream-side as the stand-off distance became large. The erosion was less observed for specimens with a large inner diameter and for a location with a long stand-off distance.

A131 MEMS技術を用いた沸騰熱伝達機構の圧力依存性(第二報)

The present paper investigated an effect of pressure on boiling heat transfer mechanism by using the MEMS technology. Steady state pool boiling experiments were conducted by using a copper thin-film for the test heater and pure water at atmospheric condition for the test liquid. The system pressure was 0.010 and 0.10 MPa, respectively. The heaters were made of a printed circuit board and a quartz glass with sputtering copper film. The test heaters had an artificial cylindrical-cavity. The cavities were fabricated by using the MEMS technology, i.e., wet etching technology. The mechanism of critical heat flux on a single boiling bubble was examined through observations of the present experiments.

20303 マイクロチャンネル内の二相流圧力損失および流動沸騰熱伝達に関する研究

The pressure drop and the heat transfer characteristics in mini pipes were investigated experimentally. Diameter of the present mini pipes was 0.089mm, respectively. Length of the test pipes channels was 20mm. The test liquid temperature was room-temperature, i.e. 20℃. A range of Reynolds number was 85<Re<384. The Present experimental results for D=0.089mm showed to be in good agreement with the conventional correlations of the pressure drop for laminar flow. The present experimental data for D=0.089mm showed to be similar to value by the conventional correlations for laminar flow.

Percolation of composite poly(vinyltrimethylsilane) membranes with carbon nanotubes

Recent years have seen a flurry of activity in research on the use of nanoparticles to improve the properties of polymeric membranes. It is known that the change in the macroscopic properties of these hybrid materials is associated with the parameters of the cluster of incorporated nanoparticles. The percolation threshold is higher than 15 vol % for the spherical particles and decreases with the increasing aspect ratio of the embedded nanoparticles of another shape. The paper presents the results of study on the permeability of gases (N2, O2, CH4 and C3H8) and a test liquid (ethanol) through hybrid membranes based on the glassy polymer poly(vinyltrimethylsilane) (PVTMS) with embedded multiwall carbon nanotubes (MWCNT) with a concentration of 0.3–3 wt %. It has been found that the permeability of gases and liquids alters at MWCNT concentrations above 0.4 wt %, which corresponds to the percolation threshold for the given particles as proved by calculations. In addition, the gas permeability coefficients measured indicate a change in the transport mechanism and selectivity of the membrane.