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1.
Ultrason Sonochem ; 108: 106970, 2024 Aug.
Article in English | MEDLINE | ID: mdl-38943847

ABSTRACT

The paper investigates the oil-water emulsification process inside a micro-venturi channel. More specifically, the possible influence of Kelvin-Helmholtz instability on the emulsification process. High-speed visualizations were conducted inside a square venturi constriction with throat dimensions of 450 µm by 450 µm, both under visible light and X-Rays. We show that cavity shedding caused by the instability results in the formation of several cavity vortices. Their rotation causes the deformation of the oil stream into a distinct wave-like shape, combined with fragmentation into larger drops due to cavitation bubble collapse. Later on, the cavity collapse further disperses the larger drops into a finer emulsion. Thus, it turns out that the Kelvin-Helmholtz instability is similarly characteristic for hydrodynamic cavitation emulsification inside a microchannel as is the Rayleigh-Taylor instability for acoustically driven emulsion formation.

2.
J Environ Manage ; 360: 121144, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38744207

ABSTRACT

Mass transfer in liquid phase is the rate-limiting step for carbon dioxide capture by ammonia water, which results in a low total mass transfer coefficient and thus a poor carbon dioxide removal efficiency. For this issue, this study established a venturi reactor with an excellent mass transfer performance to promote mass transfer rate during carbon dioxide capture, and investigated the effect of operating parameters of the venturi reactor on carbon dioxide removal efficiency and overall mass transfer coefficient. The results showed that with an increasing flow rate of the jet from 8.31 to 12.73 L/min, the carbon dioxide removal efficiency decreased due to the increase of flow rate of flue gas, and the changing trend of overall mass transfer coefficient gradually transited from increasing to decreasing with the extension of reaction time. The carbon dioxide removal efficiency and the overall mass fraction coefficient increased upon the increase of ammonia concentration from 0.1 wt% to 0.75 wt%. With the increase of inlet carbon dioxide concentration from 7% to 19%, the carbon dioxide removal efficiency and the overall mass transfer coefficient decreased. Venturi reactor was of a fast mass transfer rate during carbon dioxide capture, and the maximum CO2 removal efficiency was 96.4% at ammonia concentration of 0.75 wt%, CO2 volume concentration of 15%, flow rate of jet of 8.36 L/min. This study provided a theoretical value for the development of venturi reactor for carbon dioxide capture.


Subject(s)
Ammonia , Carbon Dioxide , Ammonia/chemistry , Bioreactors
3.
Heliyon ; 10(7): e29311, 2024 Apr 15.
Article in English | MEDLINE | ID: mdl-38633649

ABSTRACT

The Venturi flow meter offers a range of measurement options for liquids, gas, steam, and slurries in piped systems. The main criteria for assessing Venturi performance include permanent pressure loss, discharge coefficient, relative pressure loss coefficient, and measurement accuracy. However, the extended length of Venturis, relative to other flow rate measuring instruments, can present limitations in some applications. Furthermore, the manufacturing of shorter Venturis requires less material and energy. This study addresses the challenge by developing shorter Venturi meters that adhere to established performance standards. Previous studies show that cone angles, the ratio of throat diameter to inlet diameter (ß-ratio), and the throat length impact the performance of a Venturi. The scope of this research considers single-phase, incompressible and isothermal flows. The investigation focuses on the effect of cone angles for flows with Reynolds numbers ranging from 5000 to 10,000,000. Two axisymmetric Venturis, with a ß-ratio of 0.7, were designed and evaluated against an ISO-5167 classical Venturi with the same ß-ratio. Despite the ISO-5167 Venturi outperforming the others across the key criteria, a Venturi designed with a 40-degree convergent cone angle and a 10-degree divergent cone angle was 24.9 % shorter than the classical design and demonstrated similar performance to the ISO-5167 Venturi across Reynolds numbers from 100,000 to 10,000,000.

4.
Sci Rep ; 14(1): 8189, 2024 Apr 08.
Article in English | MEDLINE | ID: mdl-38589669

ABSTRACT

While numerous types of chemical cosmetic cleansers have been presented, those with sensitive skin may still experience some irritation while using them. Moreover, the environmental issue of chemical agents has been documented repeatedly. To address these, we suggest the potential application of a micro-sized bubble-laden water jet to cleanse the cosmetics without (or less) using chemical detergents. We devised a venturi-type nozzle with a mesh and air holes capable of generating massive fine bubbles. By testing with the foundation and lip tint (known to be highly adhesive) coated on the synthetic leather and artificial skin surfaces, we measured that the cleansing performance of the bubbly jet is much better (even without the chemical agent) than the single-phase liquid jet. As a mechanism for enhanced removal, it is understood that the greater kinetic energy of the jet due to the acceleration of the effective liquid-air mixture flow and the direct bubble-cosmetic collisions play essential roles. We believe that the present results will spur the development of environment-friendly cleaning methods.

5.
Data Brief ; 54: 110386, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38646196

ABSTRACT

Respiratory data was collected from 20 subjects, with an even sex distribution, in the low-risk clinical unit at the University of Canterbury. Ethical consent for this trial was granted by the University of Canterbury Human Research Ethics Committee (Ref: HREC 2023/30/LR-PS). Respiratory data were collected, for each subject, over three tests consisting of: 1) increasing set PEEP from a starting point of ZEEP using a CPAP machine; 2) test 1 repeated with two simulated apnoea's (breath holds) at each set PEEP; and 3) three forced expiratory manoeuvres at ZEEP. Data were collected using a custom pressure and flow sensor device, ECG, PPG, Garmin HRM Dual heartrate belt, and a Dräeger PulmoVista 500 Electrical Impedance Tomography (EIT) machine. Subject demographic data was also collected prior to the trial, in a questionnaire, with measurement equipment available. These data aim to inform the development of pulmonary mechanics models and titration algorithms.

6.
Materials (Basel) ; 17(4)2024 Feb 16.
Article in English | MEDLINE | ID: mdl-38399162

ABSTRACT

Additive manufacturing technologies such as directed energy deposition use powder as their raw material, and it must be deposited in a precise and controlled manner. Venturi injectors could be a solution for the highly precise transport of particulate material. They have been studied from different perspectives, but they are always under high-pressure conditions and mostly fed by gravity. In the present study, an optimization of the different dimensional parameters needed for the manufacturing of a Venturi injector in relation to a particle has been carried out to maximize the amount of powder capable of being sucked and transported for a specific flow in a low-pressure system with high precision in transport. For this optimization, simulations of Venturi usage were performed using the discrete element method, generating different variations proposed by a genetic algorithm based on a preliminary design of experiments. Statistical analysis was also performed to determine the most influential design variables on the objective, with these being the suction diameter (D3), the throat diameter (d2), and the nozzle diameter (d1). The optimal dimensional relationships were as follows: a D3 34 times the particle diameter, a d2 26.5 times the particle diameter, a d1 40% the d2, a contraction angle alpha of 18.73°, and an expansion angle beta of 8.28°. With these proportions, an 85% improvement in powder suction compared to the initial attempts was achieved, with a maximum 2% loss of load.

8.
Data Brief ; 52: 109874, 2024 Feb.
Article in English | MEDLINE | ID: mdl-38146285

ABSTRACT

Resting breathing data was collected from 80 smokers, vapers, asthmatics, and otherwise healthy people in the low-risk clinical unit at the University of Canterbury. Subjects were asked to breathe normally through a full-face mask connected to a Fisher and Paykel Healthcare SleepStyle SPSCAA CPAP device. PEEP (Positive End-Expiratory Pressure) support was increased from 4 to 12 cmH2O in 0.5 cmH2O increments. Data was also collected during resting breathing at ZEEP (0 cmH2O) before and after the PEEP trial. The trial was conducted under University of Canterbury Human Research Ethics Committee consent (Ref: HREC 2023/04/LR-PS). Data was collected by and Dräeger PulmoVista 500 EIT machine and a custom Venturi-based pressure and flow sensor device connected in series with the CPAP and full-face mask. The outlined dataset includes pressure, flow, volume, dynamic circumference (thoracic and abdominal, and cross-sectional aeration. Subject demographic data was self-reported using a questionnaire given prior to the trial.

9.
HardwareX ; 16: e00489, 2023 Dec.
Article in English | MEDLINE | ID: mdl-38058767

ABSTRACT

Respiratory model-based methods require datasets containing enough dynamics to ensure model identifiability for development and validation. Rapid expiratory occlusion has been used to identify elastance and resistance within a single breath. Currently accepted practice for rapid expiratory occlusion involves a 100 ms occlusion of the expiratory pathway. This article presents a low-cost modular rapid shutter attachment to enable identification of passive respiratory mechanics. Shuttering faster than 100 ms creates rapid expiratory occlusion without the added dynamics of muscular response to shutter closure, by eliminating perceived expiratory blockage via high shutter speed. The shutter attachment fits onto a non-invasive venturi-based flow meter with separated inspiratory and expiratory pathways, established using one-way valves. Overall, these elements allow comprehensive collection of respiratory pressure and flow datasets with relatively very rapid expiratory occlusion.

10.
J Med Case Rep ; 17(1): 446, 2023 Oct 26.
Article in English | MEDLINE | ID: mdl-37880790

ABSTRACT

INTRODUCTION: Ventricular septal defect (VSD) is one of the most common congenital cardiac anomalies. Patients with perimembranous VSD may have aortic regurgitation (AR) secondary to prolapse of the aortic cusp. CASE PRESENTATION: We present a case of 23-year-old White man with VSD, AR and ascending aortic aneurysm. The patient presented to outpatient clinic with weakness and gradual worsening shortness of breath for the past 5 years. Clinical examination revealed regular heart rhythm and loud continuous systolic-diastolic murmur (Lewin's grade 6/6), heard all over the precordium, associated with a palpable thrill. The ECG showed right axis deviation, fractionated QRS in V1 and signs of biventricular hypertrophy. The chest X-ray showed cardiomegaly. Transthoracic and transesophageal echocardiograms showed a perimembranous VSD with moderate restrictive shunt (Qp/Qs = 1.6), aortic regurgitation (AR), and ascending aortic aneurysm. Other clinical and laboratory findings were within normal limits. CONCLUSIONS: Perimembranous VSD, may be associated with aortic regurgitation and ascending aortic aneurysm as secondary phenomenon if it is not early diagnosed and successfully treated.


Subject(s)
Aneurysm, Ascending Aorta , Aortic Valve Insufficiency , Heart Defects, Congenital , Heart Septal Defects, Ventricular , Humans , Male , Young Adult , Aortic Valve Insufficiency/complications , Aortic Valve Insufficiency/diagnostic imaging , Aortic Valve Insufficiency/surgery , Heart Defects, Congenital/complications , Heart Septal Defects, Ventricular/complications , Heart Septal Defects, Ventricular/diagnostic imaging , Echocardiography
11.
Animals (Basel) ; 13(19)2023 Oct 01.
Article in English | MEDLINE | ID: mdl-37835683

ABSTRACT

Respiratory dysfunction often decreases arterial oxygen content. Four common oxygen delivery techniques-flow-by, nasal prongs, a tight-vented mask, and a tight mask connected to a Venturi valve-were evaluated for their effectiveness in increasing the oxygen reserve index (ORi), a dimensionless index of oxygen content that provides additional information compared to traditional pulse oximetry (SpO2) during hyperoxia (PaO2 100-200 mmHg), and that ranges from 0 to 1. Thirty-two dogs sedated with dexmedetomidine and an opioid were evenly divided into four groups based on the technique for oxygen administration. Each dog received oxygen at 1, 2, and 3 L/min by a single technique, and the amount of inhaled oxygen (FiO2) was measured at the level of the cervical trachea. At each flow rate, ORi and SpO2 were recorded. The flow-by method minimally increased the FiO2, and ORi reached its highest value only in 3 out of 8 dogs at the maximum flow rate. Other methods exhibited direct correlations between the oxygen flow rate and ORi (p < 0.001). These methods effectively increased FiO2 and ORi, with over half of the values exceeding 40% and 0.4, respectively. The tight-vented mask showed variable increases in FiO2, ranging between 22 and 90%. Despite method-dependent variations, all devices increased SpO2 > 98% as the FiO2 increased (p = 0.002). In conclusion, nasal prongs and the mask connected to the Venturi valve showed the highest correlation between the oxygen flow rate and the ORi. These results suggest that using these two techniques in conjunction with ORI can help in optimizing oxygen therapy.

12.
Ann Intensive Care ; 13(1): 103, 2023 Oct 17.
Article in English | MEDLINE | ID: mdl-37847454

ABSTRACT

BACKGROUND: in COVID-19 acute respiratory failure, the effects of CPAP and FiO2 on respiratory effort and lung stress are unclear. We hypothesize that, in the compliant lungs of early Sars-CoV-2 pneumonia, the application of positive pressure through Helmet-CPAP may not decrease respiratory effort, and rather worsen lung stress and oxygenation when compared to higher FiO2 delivered via oxygen masks. METHODS: In this single-center (S.Luigi Gonzaga University-Hospital, Turin, Italy), randomized, crossover study, we included patients receiving Helmet-CPAP for early (< 48 h) COVID-19 pneumonia without additional cardiac or respiratory disease. Healthy subjects were included as controls. Participants were equipped with an esophageal catheter, a non-invasive cardiac output monitor, and an arterial catheter. The protocol consisted of a random sequence of non-rebreather mask (NRB), Helmet-CPAP (with variable positive pressure and FiO2) and Venturi mask (FiO2 0.5), each delivered for 20 min. Study outcomes were changes in respiratory effort (esophageal swing), total lung stress (dynamic + static transpulmonary pressure), gas-exchange and hemodynamics. RESULTS: We enrolled 28 COVID-19 patients and 7 healthy controls. In all patients, respiratory effort increased from NRB to Helmet-CPAP (5.0 ± 3.7 vs 8.3 ± 3.9 cmH2O, p < 0.01). However, Helmet's pressure decreased by a comparable amount during inspiration (- 3.1 ± 1.0 cmH2O, p = 0.16), therefore dynamic stress remained stable (p = 0.97). Changes in static and total lung stress from NRB to Helmet-CPAP were overall not significant (p = 0.07 and p = 0.09, respectively), but showed high interpatient variability, ranging from - 4.5 to + 6.1 cmH2O, and from - 5.8 to + 5.7 cmH2O, respectively. All findings were confirmed in healthy subjects, except for an increase in dynamic stress (p < 0.01). PaO2 decreased from NRB to Helmet-CPAP with FiO2 0.5 (107 ± 55 vs 86 ± 30 mmHg, p < 0.01), irrespective of positive pressure levels (p = 0.64). Conversely, with Helmet's FiO2 0.9, PaO2 increased (p < 0.01), but oxygen delivery remained stable (p = 0.48) as cardiac output decreased (p = 0.02). When PaO2 fell below 60 mmHg with VM, respiratory effort increased proportionally (p < 0.01, r = 0.81). CONCLUSIONS: In early COVID-19 pneumonia, Helmet-CPAP increases respiratory effort without altering dynamic stress, while the effects upon static and total stress are variable, requiring individual assessment. Oxygen masks with higher FiO2 provide better oxygenation with lower respiratory effort. Trial registration Retrospectively registered (13-May-2021): clinicaltrials.gov (NCT04885517), https://clinicaltrials.gov/ct2/show/NCT04885517 .

13.
Medicina (Kaunas) ; 59(8)2023 Aug 12.
Article in English | MEDLINE | ID: mdl-37629747

ABSTRACT

Background and Objectives: Postoperative non-invasive ventilation (NIV) has been proposed as an attractive strategy to reduce morbidity in obese subjects undergoing general anaesthesia. The increased body mass index (BMI) correlates with loss of perioperative functional residual capacity, expiratory reserve volume, and total lung capacity. The aim of the current study is to evaluate the efficacy of NIV in a post-anaesthesia care unit (PACU) in reducing post-extubation acute respiratory failure (ARF) after biliointestinal bypass (BIBP) in obese patients. Materials and Methods: A retrospective analysis was conducted from January 2019 to December 2020 to compare acute respiratory failure within the first 72 postoperative hours and oximetry values of obese patients who underwent BIBP after postoperative NIV adoption or conventional Venturi mask. Results: In total, 50 patients who received NIV postoperative protocol and 57 patients who received conventional Venturi mask ventilation were included in the study. After 120 min in PACU pH, pCO2, pO2, and SpO2 were better in the NIV group vs. control group (p < 0.001). Seventy-two hours postoperatively, one patient (2%) in the NIV group vs. seven patients (12.2%) in the control group developed acute respiratory failure. Therefore, conventional Venturi mask ventilation resulted in being significantly associated (p < 0.05) with postoperative ARF with an RR of 0.51 (IC 0.27-0.96). Conclusions: After bariatric surgery, short-term NIV during PACU observation promotes a more rapid recovery of postoperative lung function and oxygenation in obese patients, reducing the necessity for critical care in the days following surgery. Therefore, as day-case surgery becomes more advocated even for morbid obesity, it might be considered a necessary procedure.


Subject(s)
Bariatric Surgery , Noninvasive Ventilation , Obesity, Morbid , Respiratory Insufficiency , Humans , Retrospective Studies , Obesity, Morbid/complications , Obesity, Morbid/surgery , Respiratory Insufficiency/etiology , Respiratory Insufficiency/therapy
14.
Ultrason Sonochem ; 99: 106552, 2023 Oct.
Article in English | MEDLINE | ID: mdl-37556974

ABSTRACT

A novel Hydrodynamic Cavitation-Assisted Oxygen Plasma (HCAOP) process, which employs a venturi tube and oxygen injection, has been developed for enhancing the production and utilization of hydroxyl radicals (·OH) in the degradation of organic pollutants. This study has systematically investigated the fluid characteristics and discharge properties of the gas-liquid two-phase body in the venturi tube. The hydraulic cavitation two-phase body discharge is initiated by the bridging of the cavitation cloud between the electrodes. The discharge mode transitions from diffuse to spark to corona as the oxygen flow rate increases. The spark discharge has the highest current and discharge energy. Excessive oxygen results in the change of the flow from bubbly to annular and a subsequent decrease in discharge energy. The effects of cavitation intensity, oxygen flow rate, and power polarity on discharge characteristics and ·OH production were evaluated using terephthalic acid as a fluorescent probe. It was found that injecting 3 standard liter per minute (SLPM) of oxygen increased the ·OH yield by 6 times with only 1.2 times increase in power, whereas<0.5 SLPM of oxygen did not improve the ·OH yield due to lower breakdown voltage. Negative polarity voltage increased the breakdown voltage and ·OH yield due to asymmetric density and pressure distribution in the throat tube. This polarity effect was explained by numerical simulation. Using indigo carmine (E132) as a model pollutant, the HCAOP process degraded 20 mg/L of dye in 5 L water within 2 min following a first-order reaction. The lowest electric energy per order (EEO) was 0.26 (kWh/m3/order). The HCAOP process is a highly efficient flow-type advanced oxidation process with potential industrial applications.

15.
Sensors (Basel) ; 23(13)2023 Jun 29.
Article in English | MEDLINE | ID: mdl-37447891

ABSTRACT

A test bench with interchangeable venturi tubes was built to automatically measure the flow parameters of pneumatic valves of a wide range of sizes. This measuring stand contained components recommended by the ISO 6358 standard, an individually configured flow meter circuit, and HMI measurement and control panels. The flow meter circuit, individually configured with interchangeable venturi tubes, bypass loops, and Setaram thermal microflow meter, was calibrated using Molbloc/Molbox equipment. The tuning curve and theoretical flow rate characteristics of the tested valve were fitted to the flow rate measurement data. The best fit value of the critical pressure ratio was obtained using the numerical method of least squares minimization. The pneumatic valve with measured flow parameters was compared with data from the catalogue on the discharge characteristics of the compressed air tank. A practical solution for high-pressure tank discharge time using two valves connected in series to the hybrid tricycle bike (HTB) pneumatic propulsion system is presented. This article presents a solution to the practical problem of measuring the flow parameters of industrial pneumatic valves with a wide range of nominal diameters on a test bench with replaceable venturi tubes.

16.
Membranes (Basel) ; 13(7)2023 Jul 14.
Article in English | MEDLINE | ID: mdl-37505031

ABSTRACT

Due to low sludge production and being a clean source without residuals, hydrogen-based autotrophic denitrification appears to be a promising choice for nitrate removal from agricultural drainage waters or water/wastewater with a similar composition. Although the incorporation of hydrogen-based autotrophic denitrification with membrane bioreactors (MBRs) enabled almost 100% utilization of hydrogen, the technology still needs to be improved to better utilize its advantages. This study investigated the anoxic treatment of both synthetic and real drainage waters using hydrogen gas in a recently developed membrane bioreactor configuration, a venturi-integrated submerged membrane bioreactor, for the first time. The study examined the effects of the inflow nitrate concentration, and the use of a venturi device on the removal efficiency, as well as the effects of the presence of headspace gas circulation and circulation rate on membrane fouling. The study found that using the headspace gas circulation through a venturi device did not significantly affect the treatment efficiency, and in both cases, a removal efficiency of over 90% was achieved. When the inlet NO3--N concentration was increased from 50 mg/L to 100 mg/L, the maximum removal efficiency decreased from 98% to 92%. It was observed that the most significant effect of the headspace gas circulation was on the membrane fouling. When the headspace gas was not circulated, the average membrane chemical washing period was 5 days. However, with headspace gas circulation, the membrane washing period increased to an average of 12 days. The study found that the headspace gas circulation method significantly affected membrane fouling. When the upper phase was circulated with a peristaltic pump instead of a venturi device, the membrane washing period decreased to one day. The study calculated the maximum hydrogen utilization efficiency to be approximately 96%.

17.
Neurosurg Rev ; 46(1): 152, 2023 Jun 26.
Article in English | MEDLINE | ID: mdl-37358703

ABSTRACT

Spinal arachnoid web (SAW) is a rare disease entity characterized as band-like arachnoid tissue that can cause spinal cord compression and syringomyelia. This study aimed to analyze the surgical management of the spinal arachnoid web in patients with syringomyelia, focusing on surgical strategies and outcomes. A total of 135 patients with syringomyelia underwent surgery at our department between November 2003 and December 2022. All patients underwent magnetic resonance imaging (MRI), with a special syringomyelia protocol (including TrueFISP and CINE), and electrophysiology. Among these patients, we searched for patients with SAW with syringomyelia following careful analysis of neuroradiological data and surgical reports. The criteria for SAW were as follows: displacement of the spinal cord, disturbed but preserved CSF flow, and intraoperative arachnoid web. Patients were evaluated for initial symptoms, surgical strategies, and complications by reviewing surgical reports, patient documents, neuroradiological data, and follow-up data. Of the 135 patients, 3 (2.22%) fulfilled the SAW criteria. The mean patient age was 51.67 ± 8.33 years. Two patients were male, and one was female. The affected levels were T2/3, T6, and T8. Excision of the arachnoid web was performed in all cases. No significant change in intraoperative monitoring was noted. Postoperatively, none of the patients presented new neurological symptoms. The MRI 3 months after surgery revealed that the syringomyelia improved in all cases, and caliber variation of the spinal cord could not be detected anymore. All clinical symptoms improved. In summary, SAW can be safely treated by surgery. Even though syringomyelia usually improves on MRI and symptoms also improve, residual symptoms might be observed. We advocate for clear criteria for the diagnosis of SAW and a standardized diagnostic (MRI including TrueFISP and CINE).


Subject(s)
Arachnoid Cysts , Spinal Cord Compression , Syringomyelia , Humans , Male , Female , Adult , Middle Aged , Syringomyelia/surgery , Syringomyelia/etiology , Spinal Cord Compression/surgery , Magnetic Resonance Imaging , Arachnoid Cysts/surgery
18.
Pulmonology ; 2023 May 27.
Article in English | MEDLINE | ID: mdl-37248102

ABSTRACT

BACKGROUND: Traditionally, Venturi-based flow generators have been preferred over mechanical ventilators to provide continuous positive airway pressure (CPAP) through the helmet (h-CPAP). Recently, modern turbine-driven ventilators (TDVs) showed to be safe and effective in delivering h-CPAP. We aimed to compare the pressure stability during h-CPAP delivered by Venturi devices and TDVs and assess the impact of High Efficiency Particulate Air (HEPA) filters on their performance. METHODS: We performed a bench study using an artificial lung simulator set in a restrictive respiratory condition, simulating two different levels of patient effort (high and low) with and without the interposition of the HEPA filter. We calculated the average of minimal (Pmin), maximal (Pmax) and mean (Pmean) airway pressure and the time product measured on the airway pressure curve (PTPinsp). We defined the pressure swing (Pswing) as Pmax - Pmin and pressure drop (Pdrop) as End Expiratory Pressure - Pmin. RESULTS: Pswing across CPAP levels varied widely among all the tested devices. During "low effort", no difference in Pswing and Pdrop was found between Venturi devices and TDVs; during high effort, Pswing (p<0.001) and Pdrop (p<0.001) were significantly higher in TDVs compared to Venturi devices, but the PTPinsp was lower (1.50 SD 0.54 vs 1.67 SD 0.55, p<0.001). HEPA filter addition almost doubled Pswing and PTPinsp (p<0.001) but left unaltered the differences among Venturi and TDVs systems in favor of the latter (p<0.001). CONCLUSIONS: TDVs performed better than Venturi systems in delivering a stable positive pressure level during h-CPAP in a bench setting.

19.
Sensors (Basel) ; 23(6)2023 Mar 07.
Article in English | MEDLINE | ID: mdl-36991590

ABSTRACT

The quality of wine is checked both during the production process and upon consumption. Therefore, manual wine-tasting work is still valuable. Due to the nature of wine, many volatile components are released, and it is therefore difficult to determine which elements need to be controlled. Acetic acid is one of the substances found in wine and is a crucial substance for wine quality. Gas sensor systems may be a potential alternative for manual wine tasting. In this work, we have developed a TGS2620 gas sensor module to analyze acetic acid levels in red wine. The gas sensor module was refined according to the Venturi effect along with signal slope analysis, providing promising results. The example included in this paper demonstrates that there is a direct relationship between the slope of the MOS gas sensor response and the acetic acid concentration. This relationship is useful to evaluate the ethanol oxidation in acetic acid in red wine during its production process.

20.
Biotechnol Appl Biochem ; 70(3): 992-1000, 2023 Jun.
Article in English | MEDLINE | ID: mdl-36385710

ABSTRACT

The current approach to gluconic acid production is acetification at 30°C, a temperature that can be difficult to maintain in tropical countries. This study investigated the production of gluconic acid during acetification by Acetobacter aceti WK at high temperatures. An acid-tolerant and thermotolerant species, A. aceti WK, was used for acetification at three different temperatures, namely, 30°C (normal temperature), 37°C, and 40°C (high temperature). Acetification was performed in a 100 L bioreactor with 0.15% CaCl2 for protection of the cells against high temperatures. The production of the organic acids, that is, acetic acid, gluconic acid, 2-keto gluconic acid, glucuronic acid, citric acid, succinic acid, lactic acid, and formic acid, was analyzed. Under acetification in the target total concentration of 80 g/L, the highest acetic acid content (39.3 g/L) was obtained at 37°C with an acetification rate of 0.3013 g/L/h, while the acetic acid content and acetification rate achieved at 30°C were 31 g/L and 0.3089 g/L/h, respectively. Additionally, gluconic acid presented at the highest concentration of 2.17 g/L. The rate of production of gluconic acid was 0.0169 g/L/h at 37°C. This acetification process at 37°C will be valuable as an alternative source for gluconic acid production for commercial applications.


Subject(s)
Acetobacter , Temperature , Fermentation , Acetic Acid
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