Liquid Injection Method Research Articles

External liquid calibration method for iodide chemical ionization mass spectrometry enables quantification of gas-phase per- and polyfluoroalkyl substances (PFAS) dynamics in indoor air.

Per- and polyfluoroalkyl substances (PFAS) are manufactured chemicals that have been detected across the globe. Fluorotelomer alcohols (FTOHs) are one PFAS class commonly found in indoor air due to emissions from consumer products (e.g., textiles and food packaging) and are human metabolic, atmospheric oxidative, and industrial precursors of perfluoroalkyl carboxylic acids (PFCAs). We developed a quantitative method for real-time analysis of gas-phase FTOHs, perfluoroalkyl acids (PFCAs and GenX), one perfluorooctane sulfonamide (EtFOSA), one fluorotelomer diol (FTdiOH), and one fluorinated ether (E2) using high-resolution time-of-flight chemical ionization mass spectrometry equipped with iodide reagent ion chemistry (I-HR-ToF-CIMS). Herein, we present a direct liquid injection method for external calibration, providing detection limits of 0.19-3.1 pptv for 3 s averaging and 0.02-0.44 pptv for 120 s averaging, with the exception of E2, which had detection limits of 1700 and 220 pptv for 3- and 120 s averaging, respectively. These calibrations enabled real-time gas-phase quantification of 6 : 2 FTOH in room air while microwaving popcorn, with an average peak air concentration of 31.6 ± 4.5 pptv measured 2 meters from a closed microwave. Additionally, 8 : 2 and 10 : 2 FTOH concentrations in indoor air were measured in the presence and absence of a rain jacket, with observed peak concentrations of 110 and 25 pptv, respectively. Our work demonstrates the ability of I-HR-ToF-CIMS to provide real-time air measurements of PFAS relevant to indoor human exposure settings and allow for PFAS source identification. We expect that real-time quantification of other gas-phase PFAS classes is possible, enabling advances in understanding PFAS sources, chemistry, and partitioning.

A facile method for fabricating super-slippery surface with long term and high-efficiency sustained release performance

Slippery liquid infused porous surfaces (SLIPS) process potential applications in surface liquid repellency, self-cleaning and anti-adhesion, while exhibiting long-term and stable release of lubricants is remaining a great challenge. Herein, an efficient liquid injection method was proposed to construct SLIPS by altering the surface energy and adjusting the inner porous structure using the facile method of direct UV irradiation. The infusion efficiency and release behavior were significantly improved and verified with various techniques such as wetting measurement, confocal fluorescence microscopy and optical microscopy. It was found that the infusion and release behavior of lubricants were varied for different specimens with different UV irradiation time. Compared to the prime substrate, PDMS treated with 90 min UV irradiation showed the highest volume of lubricant penetration which was increased almost by 833 %. Additionally, the amount of infusion consisted with the surface energy and specimens with moderate wetting exhibited the most effective lubricating performance. For the sample with 90 min UV irradiation, an ultra-low friction coefficient of 0.018 was observed under water lubrication and its releasing could be detected even after a long period of 768 h. Our results provided a facile method for the future development of long-term lubricating surfaces which may broaden their applications in fields of anti-corrosion, anti-icing and anti-fog, anti-fouling, micro-flow control and oil-water ultra-slippery occasions.

A review: Total vaporization solid-phase microextraction procedure in different matrixes

Total vaporization solid-phase microextraction (TV-SPME) is a type of extraction technique in which a specific solvent dissolves the analyte. Then a tiny amount of solvent is taken to the vial of SPME. Then, the solvent vaporizes in the SPME vial, and sampling is carried out on the headspace of the SPME fiber. As a result, the partitioning phase of the analyte between the headspace and liquid sample is omitted. The equilibrium phase remains the analyte partitioning between the headspace and SPME. TV-SPME was introduced in 2014 by Goodpaster to increase the recovery compared to the liquid injection method. This review discusses different aspects of TV-SPME, including its impact on sampling techniques, theoretical part, sampling procedure, and method optimization. Special attention was paid to its applications. A comprehensive literature study was conducted in the relevant databases to summarize the research work that has been done on this technique. In TV-SPME, the liquid samples completely vaporized and had a less matrix effect and better adsorption. This method needs no sample preparation, consumes less supply, and can be done automatically. Also, TV-SPME enables a cost-effective and efficient extraction for different matrixes. This review summarizes aspects related to TV-SPME.

Influence of injection method on the fire extinguishing efficiency of liquid nitrogen in urban underground utility tunnel

Liquid nitrogen has excellent ability of cooling and asphyxiating, which is suitable for fire extinguishing in urban underground utility tunnel. In order to obtain the influence of injection method on the fire extinguishing efficiency, a medium-sized square utility tunnel was built. Fire extinguishing experiments with different liquid nitrogen injection methods and distances were carried out. The distribution and the decrease law of oxygen volume fraction and temperature are analyzed. The result shows that the time to extinguish the fire and enter the controllable stage are greatly reduced under both conditions. Among them, the fire extinguishing efficiency of vertical injection is higher. Liquid nitrogen accumulates near the injection port first, which has a great cooling effect on this area, and acts on the fire in two stages. As the distance increases, the cooling effect is weakened and the oxygen volume fraction increases stepwise. Liquid nitrogen shows continuous cooling and asphyxiating effect during horizontal injection. It moves fast in this mode, so the difference in oxygen volume fraction is small. The initial cooling effect of vertical liquid nitrogen injection is better than that of the horizontal injection. However, the temperature at the end recovers earlier after fire extinguishing in the latter condition.

Behaviour of agglomerates formed by liquid injection in fluidized beds

AbstractFormation of agglomerates in fluidized beds can cause operating problems, such as excessive stripper shed fouling, which can lead to premature unit shut down. The focus of this study is to reach a better understanding of how agglomerates move through a fluidized bed to improve the Fluid Cokers and minimize the risk of agglomerates reaching regions where they cause problems. Two experimental methods were used: first, a Gum Arabic binder solution was injected into a two‐dimensional (2D) fluidized bed under conditions that simulate agglomerate formation in Fluid Cokers, and the mass and density of recovered agglomerates were measured; second, a new 2D radioactive particle tracking (RPT) method was developed to track the motion of model agglomerates. The fluidized bed had a steel wall, resulting in significant and non‐uniform radiation absorption. The 2D RPT system was, thus, calibrated by placing the source at 290 locations in the bed, for each fluidization velocity. Since bubble flow patterns greatly affect agglomerate motion and segregation, a tribo‐electric method was used to determine bubble flow distribution in the fluidized bed. The RPT and liquid injection methods gave similar vertical distributions of agglomerates. The main results were that increasing the fluidization velocity reduced segregation, and larger agglomerates were more likely to segregate. There was a strong correlation between the bubbles and agglomerates flow patterns: establishing an asymmetric flow pattern by injecting more fluidization gas in one side of the bed greatly reduced agglomerate segregation.

Laboratory analysis of liquid injection method on hydraulic fracturing initiation and propagation in deep shale formation

Compared with the middle-shallow shale gas reservoirs, deep shale formation often reveals lower fracture complexity, smaller effective stimulated volumes, lower conductivity, and faster declined when the same injection model and technical parameters were used. Therefore, it is necessary to research a special injection model for the deep shale formation. In this paper, a series of laboratory stimulated experiments were carried to analyze the injection method on hydraulic fracturing initiation and propagation in the deep shale formation. The outcrop shale of Longmaxi formation in Sichuan Basin was selected and three different injection methods (constant, stepped-rise and cyclic progressive uplift pump rate) were used in these experiments. The test results showed that the stepped-rise pump rate is conductive to opening the pre-existing natural fracture and bedding planes, the fracture complexity of this injection method is the highest. Meanwhile, the fracturing pressure and total injection volume are the lowest. In contrast, the cyclic-uplift injection method can only form a transverse fracture, and the fracturing pressure is the highest. The research results have an important theoretical guiding value for deep shale hydraulic fracturing operation.

Optimization and validation of in-situ derivatization and headspace solid-phase microextraction for gas chromatography–mass spectrometry analysis of 3-MCPD esters, 2-MCPD esters and glycidyl esters in edible oils via central composite design

This study aimed to develop a headspace solid-phase microextraction gas chromatography–mass spectrometry (HS–SPME–GC–MS) method for the quantification of 3-monochloropropane-1,2-diol fatty acid esters (3-MCPDEs) and 2-monochloropropane-1,3-diol fatty acid esters (2-MCPDEs), and semi-quantification of glycidyl fatty acid esters (GEs) in edible oils. A central composite design was implemented to optimize the derivatization temperature and extraction time, which were 100 °C and 80 min, respectively. HS–SPME coupled with in-situ derivatization was more straightforward (three steps) and sensitive, with a limit of detection of 16% (3.9 µg/L) and 11% (5.3 µg/L) higher than that of liquid injection method, for 3-MCPD and 2-MCPD, respectively. The recoveries of 3-MCPD and 2-MCPD were in the range of 91.1% to 102.1%, with a relative standard deviation ranging from 0.08 to 9.29%. The validated methodology was successfully applied to oil samples. Further efforts will focus on shortening the extraction time, as 80 min is relatively long.

Rising above helium: A hydrogen carrier gas chromatography flame ionization detection (GC-FID) method for the simultaneous quantification of toxic alcohols and ethylene glycol in human plasma specimens

Here we validate a GC, Flame Ionization Detection (GC-FID), liquid injection method using hydrogen as a carrier gas combining analysis of toxic volatile alcohols (VA): methanol, ethanol, isopropanol, acetone, as well as glycols, ethylene glycol (EG) and propylene glycol (PG), in a single method. Methodology200 μL of calibrator, QC, or patient specimen were deproteinized with 400 μL of acetonitrile containing internal standards (10 mmol/L N-propyl alcohol for VA and 2.5 mmol/L 1,2-butanediol for glycols). GC-FID analysis using hydrogen carrier gas and nitrogen makeup gas utilized an Agilent 7890 system equipped with Agilent 7683 liquid autosampler on a 30 m × 530 μm RTX-200 fused silica column. Method validation included repeatability, recovery, carryover, linearity, lower limit of quantification (LLOQ), accuracy, selectivity and measurement uncertainty. ResultsThe 8.3 min from injection to injection reduced time of analysis by 45% over a previously reported method using Helium carrier gas with no loss in resolution. Within-run and Between-run variability were ≤1.4% and ≤6.8% respectively. Recovery was 100% within a 95% confidence interval. Carryover was negligible for all but EG. LLOQ was <1 mmol/L for all analytes. The upper range of linearity was 120 mmol/L for methanol, ethanol and isopropanol, 100 mmol/L for acetone and 50 mmol/L for EG. Analytes demonstrated acceptable accuracy and measurement uncertainty using College of American Pathologists (CAP) criteria. Toluene can cause a false positive EG, while benzene, xylene and 1,3 butanediol can cause false negative EG. ConclusionsConverting from Helium to Hydrogen carrier gas benefits patient care through a reduction in turnaround time and provides a cost savings to the laboratory.

Molasses injection to improve growth and vitality of kesambi (Schleicera oleosa Merr) as lac insect host plant

Lac is a non-timber forest product derived from the secretion of Laccifer lacca insects that are cultivated in kesambi tree (Schleicera oleosa Merr). Low lac production in Indonesia due to poor conditions of host plant indicated by poor growth symptoms, yellowing, and falling leaves. The aim of this research was to study the effect of molasses injection on the growth and vitality of kesambi tree. Molasses were injected into the plant using passive liquid injection methods. Pre-research activities were carried out by the tree trunk injection in 0.5, 1.5, and 2 meters above the ground using gentian violet to determine the best stem injection position, while the main research activity was performed by injection of the kesambi tree trunk using molasses in concentrations of 5, 10, 15% and water as control. The parameters measured at the pre-study was translocation length of gentian violet whereas at the main research were the volume uptake, the increase of branch diameter growth, total sugar content and chlorophyll content. Pre-research results showed that 1.5 meters above the ground is the best injection position. The main research results indicated that the highest volume uptake was water followed by others treatments. Molasses injection at concentration of 10% gives better effect on the increase of branch diameter growth (4.3 mm), obtained sugar content in 18.46%. The vitality of kesambi tree also increased by the molasses injection at concentration of 10%. It was shown by thein creased of chlorophyll a (1.117 mg/g), b (0.416), carotene (0.365), and Anthocyanin (0.094 mg/100g).

Pressure drop for gas-liquid two-phase annular flow across grid spacer with mixing vane in vertical circular pipe

This study investigates the effects of mixing vane (MV) attached to a grid spacer on pressure drop for air-water annular flows in a vertical circular pipe of 16 mm I.D. In order to know the effects of MV, grid spacers with or without MV were installed in the test pipe. Three types of grid spacers with MV which has four MVs inclined 20, 30 degree from the vertical flow axis (4-MV20, 4-MV30) and two MVs inclined 30 degree (2-MV30) were used. In addition, two liquid injection methods (wall and center jet injections) are adopted to control liquid droplet entrainment faction in gas core. In the experiment, pressure drop along the channel upstream and downstream from the spacer was measured with a pressure transducer. In the analysis, the correlation of the pressure drop across the spacer is newly developed based on the present data.

垂直円管内の混合翼付きグリッドスペーサーを通過する気液二相環状流の圧力損失

This study investigates the effects of mixing vane (MV) attached to a grid spacer on pressure drop for air-water annular flows in a vertical circular pipe of 16 mm I.D. In order to know the effects of MV, grid spacers with or without MV were installed in the test pipe. Three types of grid spacers with MV which has four MVs inclined 20, 30 degree from the vertical flow axis (4-MV20, 4-MV30) and two MVs inclined 30 degree (2-MV30) were used. In addition, two liquid injection methods (wall and center jet injections) are adopted to control liquid droplet entrainment faction in gas core. In the experiment, pressure drop along the channel upstream and downstream from the spacer was measured with a pressure transducer. In the analysis, a correlation of the pressure drop across the spacer is newly developed based on the present data.

액체질소를 이용한 강관압입공법의 역학적 수리학적 안정화공법

본 연구에서는 강관압입 공법 적용 시 굴착 선단부에서 수리학적 또는 역학적 불안정으로 인해 발생 가능한 붕괴를 방지하는 목적으로 액체질소를 주입하여 굴착선단부를 안정화하는 공법에 관하여 연구하였다. 강관압입 공법 적용 시 오거 내 중공(中空)에 액체질소 주입관(호스)를 넣어 오거 선단부에 액체질소를 분사하는 방식을 고안하였다. 실내 실험을 위해 직경이 1,000 mm인 강관압입관을 기준으로 1/5축소 모형오거 및 토조를 제작하였다. 화강풍화토로 지반을 조성하여 함수비를 변화시켜가며 액체질소를 주입한 결과 오거 선단부에 동결 구근이 형성되어 강관압입공법 시공 시 발생 가능한 붕괴를 막을 수 있는 것으로 확인되었다. 액체질소를 이용한 동결공법은 지반이 모래일 때 보다는 소성이 있는 화강풍화토일 경우 더 효과적이었으며, 화강풍화토 지반의 경우 함수비가 최적함수비 이상일 경우 동결효율이 증가하는 것을 확인하였다. 액체질소 분사시간이 길어질수록 동결범위가 더 커졌으며 인위적으로 함수비를 급격히 증가시켜 수리학적 불안정을 유발해 보았더니 강관과 오거 전면의 지반이 약 120~300초 이내에 동결 되어 관으로 흙이 유입되지 않았으며, 차수효과가 있는 것으로 분석되었다. 이번 연구에서는 강관압입공법 안정화에 미치는 주요 인자에 대하여 액체질소를 이용하여 강관압입공법 시공 시 역학적 수리학적인 불안정이 발생할 경우, 화강풍화토 지반의 경우 붕괴를 막을 수 있는 효율적인 방법이 될 수 있다는 것을 확인하는데 큰 의의를 둔다. In this study, to prevent possible collapse caused by hydraulic or mechanical instability, liquid nitrogen injection method is developed and implemented at the tip of drilling auger of steel pipe propulsion tunneling. In this study, 1/5-scale model auger and sand chamber were manufactured. The prototype diameter of steel pile (or casing) is assumed about 1,000 mm. For the frictional sandy soils and plastic weathered soils, liquid nitrogen injection methods were tested varying water contents of the soils. For the induced hydraulic instability, the ground near the drilling auger was frozen within approximately 5 minutes preventing mechanical collapse and water infiltration. Securing stability of steel pile propulsion tunneling using liquid nitrogen was much more effective for which the water content of the soil somewhat exceeds the optimum water content.

마이크로 T자형 합류지점에서 기체 및 액체의 주입 방법이 기포 및 액체 슬러그 생성에 미치는 영향

마이크로 T자형 합류지점에서 기체 및 액체의 주입 방법이 기포 및 액체 슬러그 생성에 미치는 영향

Double-focusing mixing jet for XFEL study of chemical kinetics.

Several liquid sample injection methods have been developed to satisfy the requirements for serial femtosecond X-ray nanocrystallography, which enables radiation-damage-free determination of molecular structure at room temperature. Time-resolved nanocrystallography would combine structure analysis with chemical kinetics by determining the structures of the transient states and chemical kinetic mechanisms simultaneously. A windowless liquid mixing jet device has been designed for this purpose. It achieves fast uniform mixing of substrates and enzymes in the jet within 250 µs, with an adjustable delay between mixing and probing by the X-ray free-electron laser beam of up to 1 s for each frame of a `movie'. The principle of the liquid mixing jet device is illustrated using numerical simulation, and experimental results are presented using a fluorescent dye.

Study on Online Mixing Pesticide Technology and Automatic Control and Detection of Concentration

Most pesticides mixing devices adopt open-loop control mode, its mixing precision is affected by undesired signal of mixing medicine line and the precision of pesticide injection equipment.In this paper the online pesticides mixing technology with closed-loop liquid injection method and the concentration tested as the feedback signal was studied in order to obtain the high efficiency and low cost online pesticides mixer. A pesticide mixing ratio detection method and equipment based on light permeability of pesticides, a pesticide injection device controlled by PWM duty cycle and a low power consumption control unit based on single chip microcomputer MSP430F149 are designed in the research. With these units above, an online pesticide mixer with mixing ratio feedback is constructed and a fixed-point tracking experiment on the Paraquat SL mixing pesticide and water by 1:200 is conducted. The result shows that the online pesticide mixer can acquire mixing ratio information in time,automatically adjust injection volume of pesticides and accurately tracks the set of mixing ratio. The error of mixing ratio relatively less than 4.3% and the regulating time not more than 2.6s.These mean that without flowmetre controlling the technological device can realize mixing pesticide online quickly with high precision ,and the device should be economical and practical, easy to generalize, in addition ,it reduced environment pollution and operators poison risk generated by pesticide spraying.

An Integrated Approach To Design Completions for Horizontal Wells for Unconventional Reservoirs

Summary This paper presents a comprehensive and integrated workflow to design completions for a heavy-oil recovery process that involves injection and production through the same well. Unlike in traditional completion design, the transient effects are particularly important to consider while analyzing the long-term performance for these types of completions to capture the effect of variations or uncertainties in reservoir and fluid-flow characteristics over time. The proposed integrated workflow involves initial screening and selection of flow-restricting completions that can meet the desired injection and production performance based on a detailed wellbore hydraulics modeling tool. A select few completions are then analyzed for longer-term performance using a reservoir simulator that couples the flow-restricting nature of completions with flow in the reservoir. The use of best-in-art wellbore hydraulics model and reservoir simulator in a staged process yields an effective way to assess and optimize the completion design for these wells in a reduced time span. The workflow disclosed here can be used to design effective completions for a broad class of cyclic liquid-injection methods for heavy-oil resources.

Two-Phase Modeling of Leachate Recirculation Using Vertical Wells in Bioreactor Landfills

Leachate recirculation or liquid injection is an established practice for operating landfills as bioreactors to enhance the biodegradation of municipal solid waste (MSW). Among other subsurface liquid injection methods, vertical wells (VWs) represent one of the most common methods used for active or closed landfills. The current design and operation of VW systems does not consider the effect of additional liquid injection on the increase in gas pressures. In this study, a two-phase model that assumes landfill leachate and gas as immiscible phases was used to predict the moisture distribution and pore water and pore-gas pressures in a typical bioreactor landfill that uses VWs as its leachate injection or recirculation system. The unsaturated liquid and gas properties of MSW were simulated based on the van Genuchten model. The study evaluates the effect of the unsaturated hydraulic conductivity of MSW, the heterogeneous and anisotropic nature of the MSW, and the geometric configuration of VWs on moisture distribution and pore water and gas pressures. The unsaturated hydraulic properties of MSW significantly influence the wetted area and pore-water pressures during the initial stages of leachate injection and during the gravity drainage that follows. The numerical modeling results show that the gas pressures in the landfill will be of the order of 60 to 150 kPa, which are far above the liquid pressures for most typical liquid injection rates when no gas accumulation in the landfill is assumed due to an active gas extraction system. Hence, the slope stability of bioreactor landfills needs to be assessed by using the effects of gas and liquid pressures, especially when the gas extraction system is operating at below optimum efficiency.

Application of solid phase microextraction on dental composite resin analysis

A direct immersion solid phase microextraction (DI-SPME) method was developed for the analysis of dentin monomers in saliva. Dentine monomers, such as triethylene glycol dimethacrylate (TEGDMA), urethane dimethacrylate (UDMA) and 2,2-bis-[4-(2-hydroxy-3-methacryloyloxypropoxy) phenyl]-propane (Bis-GMA), have a high molecular weight and a low vapor pressure. The polydimethylsiloxane/divinylbenzene (PDMS/DVB) fiber with a medium polarity was employed for DI-SPME, and 215nm of detection wavelength was found to be optimum in the chromatogram of HPLC measurement. The calibration range for DI-SPME was 0.30–300μg/mL with correlation coefficients (r) greater than 0.998 for each analyte. The DI-SPME method achieved good accuracy (recovery 96.1–101.2%) and precision (2.30–8.15% CV) for both intra- and inter-day assays of quality control samples for three target compounds. Method validation was performed on standards dissolved in blank saliva, and there was no significant difference (p>0.2) between the DI-SPME method and the liquid injection method. However, the detection limit of DI-SPME was as low as 0.03, 0.27 and 0.06μg/mL for TEGDMA, UDMA and Bis-GMA, respectively. Real sample analyses were performed on commercial dentin products after curing for the leaching measurement. In summary, DI-SPME is a more sensitive method that requires less sample pretreatment procedures to measure the resin materials leached in saliva.

Quantitative analysis of methanol in wastewater by GC-MS with direct injection or headspace SPME sample introduction

Monitoring methanol (MeOH) concentration in wastewater treatment processes is important because methanol is a widely used carbon source for denitrification. Headspace solid-phase microextraction (HS-SPME) and direct liquid injection coupled with gas chromatography and mass spectrometry (GC/MS) were studied to analyze methanol in municipal wastewater samples in the μg mL−1 range. The conditions applied for both methods are presented. The extraction parameters for the HS-SPME method, such as SPME fiber selection, extraction temperature and time, agitation, pH value of the solution, and salt effect, were investigated. For the liquid injection method, the critical parameter was to select a polar column, the DB-WAX capillary column. Linear calibration curves were obtained over 3 orders of magnitude using methanol-d3 (MeOH-d3) or acetonitrile (ACN) as an internal standard. Both methods were validated with repeatability and recovery experiments. The liquid injection method requires a smaller injection volume and allows for faster analysis and better precision. The HS-SPME method also has reliable performance with less than 10% error. In addition, the comparison of the two methods on practical applications and maintenance is included.

Optimization of solid-phase microextraction (SPME) to determine airborne biogenic volatile organic compounds (BVOCs): An application for measurement of household cleaning products

Biogenic volatile organic compounds (BVOCs) in household cleaning products play key roles in indoor air quality (IAQ) because they are precursors for secondary pollutants formation. An accurate and rapid analytical technique for their measurement is of importance. This paper describes an optimization of a method for solid-phase microextraction (SPME) coupled with gas chromatography/mass spectrometry (GC-MS) for the determination of BVOCs. SPME fibers coated with Carboxen-PDMS are used to collect 12 individual BVOCs under standard conditions with a short exposure time of 5 min. Parameters influencing the extraction processes including sampling time, temperature and relative humidity are also investigated. All of the targeted BVOCs are shown to have limits of detection (LODs) in mixing ratios ranging from 0.31–0.50 ppbv, which are two magnitudes better than the LODs reported. The method precisions are between 1.1% and 6.7%. Comparison studies were carried out on a set of four floor cleaner extracts using the SPME method and traditional liquid injection method. Good agreement of the targeted BVOCs by the two methods was demonstrated. Our results indicated that SPME can serve as a simple and rapid sample collection approach to quantify BVOCs accurately and precisely in the indoor environment.