Venturi Pump Research Articles

Phacoemulsification Systems

Phacoemulsification Systems

Solid waste decontamination by thermal desorption and catalytic oxidation methods

AbstractCombined thermal desorption and catalytic oxidation for soil decontamination was studied at the pilot plant scale. Gasoline, xylene, and 2-methylnaphthalene were used as model contaminants in the concentrations from 2 g to 10 g per kg of soil. To guarantee the flow of the exhaust gas from the thermal desorption unit into the catalytic oxidation unit, a Venturi pump was used. Based on the laboratory scale catalytic tests, the commercial catalyst EnviCat® VOC-1544 was employed in the catalytic oxidation. Residual concentrations of hydrocarbons in soil after the thermal desorption were below the detection limits of the applied analytical method (GC-MS). Although the contaminant concentrations at the inlet of the catalytic reactor significantly varied during the experiments, the efficiency of catalytic oxidation was higher than 90 % in all cases.

Real Time Analysis of Brain Tissue by Direct Combination of Ultrasonic Surgical Aspiration and Sonic Spray Mass Spectrometry

Direct combination of cavitron ultrasonic surgical aspirator (CUSA) and sonic spray ionization mass spectrometry is presented. A commercially available ultrasonic surgical device was coupled to a Venturi easy ambient sonic-spray ionization (V-EASI) source by directly introducing liquified tissue debris into the Venturi air jet pump. The Venturi air jet pump was found to efficiently nebulize the suspended tissue material for gas phase ion production. The ionization mechanism involving solely pneumatic spraying was associated with that of sonic spray ionization. Positive and negative ionization spectra were obtained from brain and liver samples reflecting the primary application areas of the surgical device. Mass spectra were found to feature predominantly complex lipid-type constituents of tissues in both ion polarity modes. Multiply charged peptide anions were also detected. The influence of instrumental settings was characterized in detail. Venturi pump geometry and flow parameters were found to be critically important in ionization efficiency. Standard solutions of phospholipids and peptides were analyzed in order to test the dynamic range, sensitivity, and suppression effects. The spectra of the intact tissue specimens were found to be highly specific to the histological tissue type. The principal component analysis (PCA) and linear discriminant analysis (LDA) based data analysis method was developed for real-time tissue identification in a surgical environment. The method has been successfully tested on post-mortem and ex vivo human samples including astrocytomas, meningeomas, metastatic brain tumors, and healthy brain tissue.

Electrospray Post-Ionization Mass Spectrometry of Electrosurgical Aerosols

The feasibility of electrospray (ES) ionization of aerosols generated by electrosurgical disintegration methods was investigated. Although electrosurgery itself was demonstrated to produce gaseous ions, post-ionization methods were implemented to enhance the ion yield, especially in those cases when the ion current produced by the applied electrosurgical method is not sufficient for MS analysis. Post-ionization was implemented by mounting an ES emitter onto a Venturi pump, which is used for ion transfer. The effect of various parameters including geometry, high voltage setting, flow parameters, and solvent composition was investigated in detail. Experimental setups were optimized accordingly. ES post-ionization was found to yield spectra similar to those obtained by the REIMS technique, featuring predominantly lipid-type species. Signal enhancement was 20- to 50-fold compared with electrosurgical disintegration in positive mode, while no improvement was observed in negative mode. ES post-ionization was also demonstrated to allow the detection of non-lipid type species in the electrosurgical aerosol, including drug molecules. Since the tissue specificity of the MS data was preserved in the ES post-ionization setup, feasibility of tissue identification was demonstrated using different electrosurgical methods.

On‐line reaction monitoring by extractive electrospray ionisation

The design and development of a novel extractive electrospray ionisation (EESI) device for on-line reaction monitoring is described. The EESI apparatus uses a secondary, grounded nebuliser to produce an analyte aerosol and a Venturi pump is then used to transfer a sample of the aerosol to an electrospray source where it is ionised. The EESI apparatus was then tested with a variety of small, organic molecules to assess sensitivity, linearity and dynamic range. The performance of the technique will depend on the mass spectrometer used for the experiments; in the configurations used here it has a usable dynamic range of around 3.5 orders of magnitude with a linear range of around 2.5 orders of magnitude and is capable of analysing species present down to low µg/mL with signal-to-noise ratio greater than 2.5. The use of EESI for reaction monitoring was validated using a series of mock reaction mixtures and then used to monitor the base hydrolysis of ethyl salicylate to salicylic acid.

Comparison of peristaltic and Venturi pumps in bimanual microincisional cataract surgery

Comparison of peristaltic and Venturi pumps in bimanual microincision phacoemulsification on the success of the cataract surgery by using sleeveless phaco tip. Bimanual microincision phacoemulsification was done in 49 eyes using a 1.4-mm temporal clear corneal incision. A peristaltic pump was used in 23 eyes, and a Venturi pump was used in 26 eyes for phacoemulsification. Intraoperative complications, anterior chamber stability, and mean duration of surgery were recorded. Duration of surgery was shorter in the Venturi pump group. Anterior chamber stability could not be established in 17 eyes in the peristaltic pump group; it was established in all eyes in the Venturi pump group. Corneal burns were observed in two eyes in the peristaltic pump group and no eyes in the Venturi pump group. Use of a Venturi pump system and a vented gas-forced infusion system can significantly shorten surgery time and reduce risk of thermal burns.

391 La pointe en « petite trompette » de la pièce à main du phaco-émulsificateur dans la chirurgie de la cataracte : un an d’expérience

To evaluate the performance of “Tromb tip”, a new phacoemulsification tip for cataract surgery and to report outcomes after an 18-month follow-up period. Fifty-two eyes of 52 patients (24 male and 28 female; mean age 67±12 years), scheduled for phacoemulsification cataract surgery were included in the study. All patients underwent a 2.1 mm clear corneal incision, biaxial phacoemulsification with the flat-shaped “Tromb tip”, and a foldable intraocular lens (IOL) implant. All patients underwent complete ophthalmologic examination, corneal topography, and non-contact specular microscopy 1 week before and 12 months after surgery. Visual outcomes, surgical induced astigmatism (SIA), central corneal endothelial cell (CCEC) count and surgical instrumental parameters were considered in the analysis. The mean best corrected visual acuity increased from 0.4 to 0.9; mean SIA was 0.55±0.50 diopters; and, CCEC loss was 7±5%. There were no intraoperative or postoperative complications in our cohort of patients. Surgical phacoemulsification duration ranged from 45 to 180 s. Mean ultrasound percentage was 25% (range 10-40%). Mean vacuum rate (Venturi pump) was 90 mmHg. The Tromb-tip has a flat tip that fits well in the corneal incision without inducing stretch or deformation. There is greater surface contact between the tip and the cornea, thus causing less friction energy and heat production per unit of contact area. The 17 Gauge lumen, also maximizes aspiration (which requires greater irrigation) and shortens surgical time. The Tromb-tip is a good alternative to the traditional round phaco-tips.

Cataract surgery using the bimanual phacoemulsification technique with an Accurus system and Mackool microphaco tip

To investigate the safety and effectiveness of the Accurus vitreoretinal and phacoemulsification system (Alcon, Inc.) for bimanual phacoemulsification surgery. Kosei Chuo Hospital, Tokyo, Japan. Phacoemulsification for age-related cataract was performed using a bimanual technique in 55 eyes and a coaxial technique in 31 eyes. The Accurus system with a venturi pump and a sleeveless ultrasonic tip or a Mackool microphaco tip was used in all cases. The 2 techniques were compared. In bimanual phacoemulsification, the 2 tips were evaluated to determine whether either reduced ocular tissue impairment. The mean best corrected visual acuity 1 day after the surgery was 20/20 in both groups. There was no significant difference between the bimanual group and coaxial group except in ultrasound output (bimanual 22%, coaxial 28%; P = .01). Iris impairment was observed only in the bimanual group but was reduced by the use of the Mackool sleeved microphaco tip. Bimanual phacoemulsification for cataract surgery using the Accurus system with a venturi pump and a Mackool microphaco tip was safe and effective and may provide a means of performing combined or successive cataract and vitreoretinal surgery.

Objective Measurement of Postocclusion Surge During Phacoemulsification in Human Eye-Bank Eyes

To objectively compare the postocclusion vacuum surge among different phacoemulsification machines and devices. Experimental study. Infiniti, Legacy, Millennium, and Sovereign were tested in an eye-bank eye. All the machines were tested with 20-gauge non-ABS tips, 430 mm Hg vacuum pressure, 24 ml/minute aspiration rate, peristaltic pump, and 75 cm bottle height. In addition, Infiniti and Legacy were also tested with 20-gauge bypass tips (ABS), 125 cm bottle height, and 40 ml/minute flow rate. We also tested 19-gauge tips with Infiniti and Sovereign and the venturi pump for Millennium. Significant differences were found between all the machines tested with Millennium peristaltic generating the least and Millennium Venturi the most surge. ABS tips significantly decreased the surge for Legacy but not for Infiniti. Cruise Control (CC) had a significant effect on Sovereign but not on Millennium. Increasing the bottle height decreased surge while increasing the flow increased surge for both Infiniti and Legacy. The 19-gauge tips increased surge for both Infiniti and Sovereign. Surge varied over a range of 40 microm to more than 2 mm. ABS and CC decrease surge, especially when the machine is not functioning near the limits of surge prevention. Certain parameters, such as a 19-gauge tip and high flow, dramatically increased surge, whereas elevating the bottle ameliorates it. Understanding the impact of all these features will help in minimizing the problem.

Comparaison des différents systèmes de vitrectomie

The vitrectomy systems in use today have greatly improved from a technical point of view since the introduction of this surgical technique in the 1970s. The TSV 25 (Transconjunctival Standard vitrectomy) using 25-gauge vitrectomy probes and the high-speed vitrectomy module is one of the latest significant advances. This new system does a complete vitrectomy without opening or closing the conjunctiva. At the present time, three different aspiration modes (venturi, peristaltic and concentrix), two different probe diameters (20- and 25-gauge) and two cutting modes (pneumatic and high-speed) are available. The author assessed and compared the efficacy of the two different probe diameters and the two different cutting modes available with the venturi pump on the Millennium (Millennium Microsurgical system, Bausch & Lomb, Saint Louis, MO). These estimates highlighted the better efficacy of the high-speed cutting mode in comparison to the pneumatical mode. Regarding the probe diameters, the 25-gauge probe is less efficient than the 20-gauge probe. Nevertheless, the flow difference between the two is minimal in comparison to its clinical benefit.

In-vivo test of bi-directional venturi pump for emergency transtracheal lung ventilation

In-vivo test of bi-directional venturi pump for emergency transtracheal lung ventilation

Venturi-assisted liquid removal from the sump of a gas well

Gas wells produce not only gas, but also a small amount of liquid which, being dense, can collect at the bottom of the well. The well may slowly fill with liquid, and gas production is reduced, or stopped completely, when the perforations through which gas flows into the well are submerged. A simple Venturi pump can be used to re-disperse the liquid into the gas flowing to the surface. The pressure available for lifting liquid into the Venturi throat is not large, and it is therefore advantageous if gas is mixed into the liquid, thereby reducing the effective density of the mixture which has to be lifted. An analysis based solely on Bernoulli’s equation and hydrostatic pressures is surprisingly rich, and gives good agreement with experiment when empirical relations for turbulent wall friction are included.

Implantation and capsular bag stability of single-piece, foldable easacryl 1 intraocular lenses

Purpose To assess the folding and implantation of the single-piece EasAcryl 1 intraocular lens (IOL) and the maintenance of the tunnel structure and capsular bag stability after implantation. Setting S. Orsola Hospital Department of Pathophysiologic Optics, University of Bologna, Bologna, Italy. Methods This study comprised 300 cases of EasAcryl 1 IOL implantation. First, a 3.2 mm corneal incision was made according to preoperative astigmatism followed by a 5.5 mm ± 0.3 (SD) capsulorhexis. After sutureless phacoemulsification using a venturi pump, the 6.0 mm optic, 11.0 mm diameter IOL was implanted using a hexagonal cartridge. The IOLs were implanted using a 2-step maneuver when the superior haptic was grasped with the forceps (first case) or a 1-step maneuver when only the Microsert injector was used. The cartridge was never pushed beyond the tunnel. The preoperative and postoperative incision size and the corneal surgically induced astigmatism were recorded. The IOL rotation was measured 30 ± 5 days and 8 ± 1 months postoperatively. Results No intraoperative complications occurred after the learning curve. No alteration in astigmatism was observed. The mean IOL rotation was 1.04 ± 0.5 degrees at 30 ± 5 days and 1.02 ± 0.2 degrees at 8 ± 1 months. Conclusions The EasAcryl 1 was easily implantation through a 3.2 mm tunnel without altering the natural architecture. The unfolding of the IOL was well controlled, and the IOL remained well centered. A short learning curve is required.

Causes and prevention of photochemical reduction of hexavalent chromium during x‐ray photoelectron spectroscopy

AbstractWe report on the photoreduction of hexavalent chromium during exposure to soft x‐rays used in x‐ray photoelectron spectroscopy (XPS). Photoreduction of hexavalent chromium to the tetravalent state in both CrO3 and K2CrO4 was found to involve hydrocarbons adsorbed onto the sample surface during rough pumping with a rotary pump during sample entry. When rough pumping was performed by a Venturi pump and a sorption pump, no photoreduction was observed over a period of 6 h of exposure to soft x‐rays. We also observed that Cr(IV) was stable under soft x‐ray radiation. In the presence of water vapor in the vacuum chamber, Cr(IV) was chemically reduced to Cr(III). The findings of this study bring into question the applicability of current models explaining the photoreduction of high‐valent chromium oxides during XPS, and are also of general interest. Copyright © 2001 John Wiley & Sons, Ltd.

New class of microminiature Joule — Thomson refrigerator and vacuum package

Progress is reported on the development of a two-stage, fast cooldown Joule — Thomson refrigerator using nitrogen gas and a nitrogen — hydrocarbon gas mixture as the refrigerants. The refrigerator incorporates a microminiature Venturi pump to reduce the pressure of the exhaust of the main boiler to bring the operating temperature of the cold stage to < 70 K in as little as 10 s. The vacuum package for the refrigerator contains no organic materials and is designed to provide a ten year shelf life. Special glass strengthening techniques are being used to achieve cooler survival of acceleration tests of up to 100 000g.

水スプレー冷却炉蓋

Water-cooled-panels for electric arc furnaces have been very popular with the spread of the ultra-high-powered operation. These panels, however, have the problem that cooling water pours in furnace through the hole caused by thermal fatigue and thermal overload. To improve the water-cooled-panels, the spray-cooled-roof system has been developed by Ucar Carbon Co., Inc. This system is characterized by that water spray hits the roof panel and the sprayed water is drained by Venturi pump to maintain the atmospheric pressure in the roof structure.Daido Steel has introduced this technology and conducted the test operation using the 70 tons electric arc furnace in Chita plant. As a results, it is expected the elongation of the service life, the improvement of operational rate, safer operation and the decrease in maintenance costs. Based on these test results, this system will be applied to the commercial production line in Japan.

Voltammetric determination of airborne 2-chloronitrobenzene using a recirculating absorbent vapour sampler.

A system designed to pre-concentrate atmospheric vapour samples into a recirculating absorbent and which is suitable for direct voltammetric analysis is described. A Meinhard nebuliser operates as a venturi pump to allow circulation and dispersion of the absorbent into a fine aerosol, suitable for efficient collection of vapour samples. The incoming gas phase drives the nebuliser from which the mixed aerosol-vapour sample is condensed in a length of glass tubing. The pre-concentrated sample is circulated through an electrochemical cell for voltammetric detection at a hanging mercury drop electrode. The optimum electrochemical conditions for the determination of test atmospheres containing 2-chloronitrobenzene at levels of 1.5–4.3 × 10–4 g m–3 for sampling periods of between 30 and 813 s at a flow-rate of 0.18 dm3 s–1 are described.