Continuous Oxygen Flow Research Articles

Randomized crossover trial of a demand oxygen delivery system in nocturnal hypoxemia

The newly developed portable oxygen concentrator with an auto-demand oxygen delivery system (auto-DODS) automatically switches between 3 sensitivities according to the negative pressure gradient of inhalation and supplies oxygen only during inhalation. The aim of this study was to verify the effectiveness and safety of auto-demand devices compared with a continuous flow oxygen concentrator, during sleep, in a randomized crossover noninferiority trial. We alternatively used an auto-DODS or a continuous-flow oxygen concentrator, all night on separate days for HOT (Home Oxygen Therapy) patients with nocturnal hypoxemic symptoms. The primary endpoints were the mean value of oxygen saturation (SpO2) over the total sleep time. The secondary endpoints included the efficacy endpoints and the safety endpoints. Regarding the primary endpoint, the difference in SpO2 between the auto-DODS and continuous flow was 0.835%. Since the upper limit of this difference did not exceed 2.8, which was set as the noninferiority margin, it was shown that the auto-DODS did not reduce SpO2 by at least 2.8% on average compared to continuous flow. No equipment failure or exacerbation of disease was observed, confirming the safety of the auto-DODS during the night.

Synthesis and Characterization of DOPO-Containing Poly(2,6-dimethyl-1,4-phenylene oxide)s by Oxidative Coupling Polymerization.

A set of polyphenylene oxides incorporating DOPO (9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide) functionality, denoted as DOPO-R-PPO, was synthesized by copolymerization of 2,6-dimethylphenol (2,6-DMP) with various DOPO-substituted tetramethyl bisphenol monomers. In the initial step, a Friedel-Crafts acylation reaction was employed to react 2,6-DMP with different acyl chlorides, leading to the formation of ketone derivatives substituted with 2,6-dimethylphenyl groups. Subsequently, the ketones, along with DOPO and 2,6-DMP, underwent a condensation reaction to yield a series of DOPO-substituted bisphenol derivatives. Finally, polymerizations of 2,6-dimethylphenol with these DOPO-substituted bisphenols were carried out in organic solvents using copper(I) bromide/N-butyldimethylamine catalysts (CuBr/DMBA) under a continuous flow of oxygen, yielding telechelic PPO oligomers with DOPO moieties incorporated into the polymer backbone. The chemical structures of the synthesized compounds were characterized using various analytical techniques, including Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (1H NMR), phosphorus nuclear magnetic resonance (31P NMR), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). When compared to conventional poly(2,6-dimethyl-1,4-phenylene oxide)s with a similar molecular weight range, all DOPO-PPOs exhibited higher glass transition temperatures, enhanced thermal degradability, and increased char yield formation at 800 °C without compromising solubility in organic solvents.

Methodical control of the difficult pediatric airway: two case reports

BackgroundManagement of children who present with a history of impossible mask ventilation or difficult tracheal intubation is fraught with challenges. Despite this, the “airway stress test” of an inhalational induction is frequently employed risking airway obstruction, breath holding, apnea, and laryngospasm.Case presentationsWe present two cases of children with anticipated difficult airway management. The first child (14-year-old African American boy) had severe mucopolysaccharidosis with a history of failed anesthetic induction and failed airway management. The second child (3-year-old African American girl) had progressive lymphatic infiltration of the tongue, resulting in severe macroglossia. We describe a technique that forgoes inhalational induction, incorporates recent pediatric airway guidelines, and provides a greater margin of safety. The technique encompasses the use of drugs that facilitate sedation for intravenous access, without respiratory depression or airway obstruction, titrated use of medications to achieve anesthetic depth while preserving ventilatory drive and airway tone, and the continuous provision of directed oxygen flow during airway manipulation. Propofol and volatile gases were avoided to preserve airway tone and respiratory drive.ConclusionsWe emphasize that an intravenous induction technique utilizing medications that preserve airway tone and ventilatory drive, and the use of continuous oxygen flow throughout airway manipulation, allows for successful management of children with a difficult airway. The common practice of volatile inhalational induction should be avoided in anticipated difficult pediatric airways.

Systematic review and meta-analysis of efficacy and safety of continuous positive airways pressure versus high flow oxygen cannula in acute bronchiolitis

IntroductionThere are a trend towards increasing use of High-Flow Nasal Cannula (HFNC), outside of paediatric intensive care unit. Give this trend is necessary to update the actual evidence and to assess available published literature to determinate the efficacy of HFNC over Continuous Positive Air Pressure (CPAP) as treatment for children with severe bronchiolitis.MethodsWe searched MEDLINE, EMBASE, LILACS, and COCHRANE Central, and gray literature in clinical trials databases (www.clinicaltrials.gov), from inception to June 2022. The inclusion criteria for the literature were randomized clinical trials (RCTs) that included children < 2 years old, with acute moderate or severe bronchiolitis. All study selection and data extractions are performed independently by two reviewers.ResultsThe initial searches including 106 records. Only five randomized controlled trial that met the inclusion criteria were included in meta-analysis. The risk of invasive mechanical ventilation was not significantly different in CPAP group and HFNC group [OR: 1.18, 95% CI (0.74, 1.89), I² = 0%] (very low quality). The risk of treatment failure was less significantly in CPAP group than HFNC group [OR: 0.51, 95% CI (0.36, 0.75), I² = 0%] (very low quality).ConclusionIn conclusion, there was no significant difference between HFNC and CPAP in terms of risk of invasive mechanical ventilation. CPAP reduces de risk of therapeutic failure with a highest risk of non severe adverse events. More trials are needed to confirm theses results.

Evaluation of Over-the-Counter Portable Oxygen Concentrators Utilizing a Metabolic Simulator.

Supplemental oxygen is designed to raise alveolar PO2 to facilitate diffusion into arterial blood. Oxygen is generally delivered by nasal cannula either by continuous or pulsatile flow. Battery-powered portable oxygen concentrators (POCs) facilitate ambulation in patients experiencing exertional hypoxemia. In the United States, the Food and Drug Administration (FDA) clears these devices to be sold by physician prescription. Recently, however, lower-cost devices described as POCs have been advertised by online retailers. These devices lack FDA clearance and are obtained over the counter (OTC) without prescription. This study determined whether a selected group of OTC POCs have oxygen delivery characteristics suitable for use by hypoxemic patients. A metabolic simulator, capable of simulating a range of metabolic rates and minute ventilations, determined effects of oxygen supplementation delivered by a variety of devices on alveolar PO2 . Devices tested included 3 OTC POCs, an FDA-cleared POC, and continuous-flow oxygen from a compressed oxygen cylinder. End-tidal PETO2 , a surrogate of alveolar PO2 , was determined at each of each device's flow settings at 3 metabolic rates. Continuous-flow tank oxygen yielded a linear PETO2 increase as flow increased, with progressively lower slope of increase for higher metabolic rate. The prescription POC device yielded similar PETO2 elevations, though with somewhat smaller elevations in pulse-dose operation. One OTC POC was only technically portable (no on-board battery); it provided only modest PETO2 elevation that failed to increase as flow setting was incremented. A second OTC POC produced only minimal PETO2 elevation. A third OTC POC, a pulsed-dose device, produced meaningful PETO2 increases, though not as great as the prescription device. Only one of 3 OTC POCs tested was potentially of use by patients requiring ambulatory oxygen. Physicians and respiratory therapists should inform patients requiring portable oxygen that OTC devices may not meet their oxygenation requirements.

Retro-fitment of an oxygen system in a transport aircraft of Indian Air Force: Decompression chamber trials to assess system functionality

The aeromedical concerns of sudden onset hypoxia and rapid decompression are an omnipresent threat to flight safety when flying over 10,000 ft. The concept of Time of Useful Consciousness (TUC) provides the aircrew a window to correct his predicament. The issues of hypoxia are mitigated in transport aircraft with cabin pressurization. However, the requirement of an oxygen system in these aircraft is considered essential in an emergency in case of cabin failure of cabin pressurization or rapid decompression, despite adequate TUC, as it provides immediate succor from anxiety, and subtle performance decrements, especially in VIP carriage or casevac roles. With this background, a requirement for retro-fitment of a functional oxygen system of a small transport ac of Indo-German origin into a pressurized medium-lift cargo aircraft of British Origin was envisaged. Toward this, ground-based simulator trials were conducted on the oxygen system to assess its functionality before undertaking flight trials in the aircraft. The assessment consisted of the ground trial of the test oxygen system in the Explosive Decompression Chamber with three experiment protocols. The experimentation involved exposure to a simulated altitude of 15,000 ft for 25 min and rapid decompression from 7000 to 15,000 ft. Physiological parameters, endurance, and flow of oxygen in the system were evaluated. The trial results indicated that the physiological parameters (heart rate, respiratory rate, oxygen saturation [SpO2], and end-tidal carbon dioxide [EtCO2]) were within normal limits during the entire duration of exposure to 15,000 ft and decompression from 7000 ft to 15,000 ft. In addition, the physiological parameters were also within normal limits during exposure to 1 min of simulated hyperventilation. Neither any subjective or objective symptoms of hypoxia were observed nor any appreciation of increased breathing resistance reported by the subjects. The endurance of the system in terms of delivering continuous oxygen flow at 15,000 ft was assessed to be 73 min. From the trials, it was inferred that the oxygen system in a single crew configuration could be used satisfactorily up to the operational ceiling altitude specified for the subject aircraft.

Comparison of Efficacy of Epinephrine to Salbutamol and Ipratropium Bromide Combined in Acute Bronchiolitis

Background: Epinephrine, an alpha receptor agonist, has been suggested to be a supreme bronchodilator. A biologically active drug name Ipratropium bromide is helpful for the treatment of bronchiolitis among infants and improves on the signs and symptoms of bronchiolitis. Objective: To compare effectiveness of combined nebulized salbutamol with nebulized adrenaline and ipratropium bromide in bronchiolitis affected children in terms of mean improvement in RDAI score. Methodology: After approval from ethical committee this randomized control trial of 6 month duration is carried out by Randomization of patients in 2 groups. Group A received salbutamol (0.15mg/kg) combined with ipratropium bromide (250 micrograms per dose) with isotonic sodium chloride solution 0.9% (2 mL) and Group B received a dose of epinephrine (0.5mg/kg in concentration of 1:1000(max 5 mg), distributed by nebulizer with the help of a face mask with continuous oxygen flow at 6L/min Prior to each drug administration and at 30 mints, the researcher evaluated the condition of infant’s and records the respiratory rate, RDAI score9, heart rate and SaO2. RESULTS: Comparison of effectiveness of combined nebulized salbutamol with nebulized adrenaline and ipratropium bromide in bronchiolitis affected children in terms of mean improvement in RDAI score shows that at baseline in Group-A it was 10.73+1.59 and 10.98+1.42, p value was 0.27, it was reduced after 30 minutes of treatment in Group-A 3.23+0.52 and 2.67+0.47 in Group-B, p value was 0.001. Conclusion: We concluded that Epinephrine is better than salbutamol and ipratropium combined in terms of mean improvement in RDAI score Keywords: Bronchiolitis, children, salbutamol and ipratropium Bromide, Epinephrine.

Helium-flushed sheathed nickel tube reactor for continuous flow oxygen stable isotope compound-specific analysis.

Compound-specific oxygen stable isotope analysis has been commercially available for about 20 years but the technique has been infrequently applied and practical operating knowledge is limited. Existing reactor designs and chemistry fail to fully exclude contaminating oxygen, are chromatographically flawed, and are generally fabricated from expensive platinum tubing. As a new interface between the gas chromatograph and isotope ratio mass spectrometer, we used a nickel tube reactor (containing no platinum wires) in a ceramic sheath with countercurrent helium flushing, operated at 1250°C. We analyzed suites of four long-chain alcohols (LCAs), defining the least and most 18 O-enriched LCAs as internal standards. The other two LCAs, co-injected in varying amounts, were treated as unknowns and amplitude-corrected during data reduction. With this design, signals from non-oxygenated compounds are minimized with a hydrogen trickle, while excessive graphitization is counterproductive. A balance of hydrogen and graphite is required to maintain a proper, stable redox state in the reactor. With low extraneous oxygen, the exact hydrogen flow has little effect on final δ18 O data quality. Overall average δ18 O values precisions and errors for the unknowns were better than 0.4‰ for injections between 2 and 7nmol per component. Our actively flushed sheath reduces oxygen infiltration to negligible levels and results in a chromatographic flow devoid of dead or poorly swept volumes. The improved design allows measurement of LCAs with accuracy and precision sufficient to enable investigating real processes, and may also have wider applications to other isotopes.

Oxygenation and Hemodynamic Changes in Traumatic Brain Injury: A Literature Review

Traumatic brain injury (TBI) is a major public health problem and the main cause of death and disability worldwide. TBI can causing primary and secondary injury. Primary brain injury occurs within a moment after a collision and worsen by acute systemic damage such as hypoxia, bleeding, and neurotoxic pathway activation. Under normal conditions, brain has several mechanisms for regulating pressure and volume to prevent ischemia. The purpose of these mechanisms is to maintain a continuous cerebral blood flow (CBF) and adequate oxygen supply.

Changes of blood gas and serum indexes in patients with acute heart failure complicated with respiratory failure treated by noninvasive ventilator.

Objective:To observe the changes of blood gas and serum indexes in patients with acute heart failure complicated with respiratory failure treated by noninvasive ventilator-assisted ventilation.Methods:The records of patients with acute heart failure and respiratory failure, treated in our hospital from June 2019 to June 2021, were selected and stratified based on the received therapy. Of a total of 168 patients, 81 received continuous low flow oxygen therapy (control group) and 87 received noninvasive ventilator (NIV)-assisted ventilation therapy (NIV group). The blood gas and serum indexes of the two groups were compared and analyzed.Results:After 48 hours of treatment, the blood oxygen saturation (SaO2), arterial partial pressure of oxygen (PaO2) and oxygenation index (PaO2/FiO2) in patients in the NIV group were higher than those in the control group, while the expression of arterial partial pressure of carbon dioxide (PaCO2) was lower than that in the control group (P<0.05). After 24 hours and 48 hours of treatment, there was an increase in the expression of N-terminal pro-B-type natriuretic peptide (NT-pro BNP) and Cardiac troponin I (cTnI) in both groups. The expression of NT-pro BNP and cTnI in the NIV group was significantly lower than that in the control group (P<0.05).Conclusion:In patients with acute heart failure and respiratory failure, noninvasive ventilator-assisted ventilation results in improved blood gas analysis indexes and lower levels of heart disease markers, NT-pro BNP and cTnI.

Decomposition of Hydrogen Peroxide using Chemical and Catalytic Methods: A Reactor-based Approach

A feasible catalytic reactor for oxygen evolution has been proposed, which could complement the current methods of O2 evolution efficiently and ensure the availability of pure oxygen on a wider scale. Several chemicals, such as NaI, MnO2, NiSO4, etc. can generally decompose hydrogen peroxide by producing oxygen as a product via chemical reactions. Meanwhile, the Pt-Pd catalyst efficiently catalyzes hydrogen peroxide decomposition reactions and generates pure oxygen without any unfriendly species. The excellence of the bi-metallic catalyst has been validated by the evaluation of turnover number (TON) and turnover frequency (TOF). Implementing the knowledge of chemical reactions and heterogenous catalysis, the proposed catalytic reactor could be helpful for generating a continuous flow of oxygen. Surely, the oxygen produced in this process is higher in amount compared to the oxygen present in the atmosphere at ambient conditions which might facilitate the breathing support for critically ill patients.

Robust, maintainable, emergency invasive mechanical ventilator.

To develop a simple, robust, safe and efficient invasive mechanical ventilator that can be used in remote areas of the world or war zones where the practical utility of more sophisticated equipment is limited by considerations of maintainability, availability of parts, transportation and/or cost. The device implements the pressure-controlled continuous mandatory ventilation mode, complemented by a simple assist-control mode. Continuous positive airway pressure is also possible. The consumption of compressed gases is minimized by avoiding a continuous flow of oxygen or air. Respiratory rates and inspiration/expiration time ratios are electronically determined, and an apnea/power loss alarm is provided. The pressure profiles were measured for a range of conditions and found to be adjustable within a ± 2.5cmH2O error margin and stable well within this range over a 41-hour period. Respiratory cycle timing parameters were precise within a few percentage points over the same period. The device was tested for durability for an equivalent period of four months. Chemical and biological tests failed to identify any contamination of the gas by volatile organic compounds or microorganisms. A ventilation test on a large animal, in comparison with a well established ventilator, showed that the animal could be adequately ventilated over a period of 60 minutes, without any noticeable negative aftereffects during the subsequent 24-hour period. This ventilator design may be viable, after further animal tests and formal approval by the competent authorities, for clinical application in the abovementioned atypical circumstances.

Manual Conservation of Supplemental Oxygen in Low-Resource Settings During the COVID-19 Pandemic.

Summary StatementUsing a simulated adult COVID-19 patient with hypoxemia, we investigated whether caregivers interrupting oxygen flow by manually occluding oxygen tubing with pliers during exhalation can conserve oxygen while maintaining oxygenation. Oxygen pinching reduced oxygen use by 51% to 64%, maintained simulated oxygen saturation between 88% and 90%, and increased simulated average alveolar partial pressure of oxygen from a room air baseline of approximately 131 to 294–424 mm Hg compared with 607 mm Hg with 10 liters per minute (LPM) continuous oxygen flow. Simulation provided a methodology to rapidly evaluate a technique that has begun to be used with COVID-19 patients in low-resource environments experiencing an acute oxygen shortage.

How prepared is Mozambique to treat COVID-19 patients? A new approach for estimating oxygen service availability, oxygen treatment capacity, and population access to oxygen-ready treatment facilities

BackgroundThis study aims to assess the COVID-19 response preparedness of the Mozambican health system by 1) determining the location of oxygen-ready public health facilities, 2) estimating the oxygen treatment capacity, and 3) determining the population coverage of oxygen-ready health facilities in Mozambique.MethodsThis analysis utilizes information on the availability of oxygen sources and delivery apparatuses to determine if a health facility is ready to deliver oxygen therapy to patients in need, and estimates how many patients can be treated with continuous oxygen flow for a 7-day period based on the available oxygen equipment at health facilities. Using GIS mapping software, the study team modeled varying travel times to oxygen-ready facilities to estimate the proportion of the population with access to care.Results0.4% of all health facilities in Mozambique are prepared to deliver oxygen therapy to patients, for a cumulative total of 283.9 to 406.0 patients-weeks given the existing national capacity, under varying assumptions including ability to divert oxygen from a single source to multiple patients. 35% of the population in Mozambique has adequate access within one-hour driving time of an oxygen-ready health facility. This varies widely by region; 89.1% of the population of Maputo City was captured by the one-hour driving time network, as compared ot 4.4% of the population of Niassa province.ConclusionsThe Mozambican health system faces the dual challenges of under-resourced health facilities and low geographic accessibility to healthcare as it prepares to confront the COVID-19 pandemic. This analysis also illustrates the disparity between provinces in preparedness to deliver oxygen therapy to patient, with Cabo Delgado and Nampula being particularly under-resourced.

A feasibility study evaluating a reservoir storage system for continuous oxygen delivery for children with hypoxemia in Kenya

BackgroundSupplemental oxygen is an essential treatment for childhood pneumonia but is often unavailable in low-resource settings or unreliable due to frequent and long-lasting power outages. We present a novel medium pressure reservoir (MPR) which delivers continuous oxygen to pediatric patients through power outages.MethodsAn observational case series pilot study assessing the capacity, efficacy and user appraisal of a novel MPR device for use in low-resource pediatric wards. We designed and tested a MPR in a controlled preclinical setting, established feasibility of the device in two rural Kenyan hospitals, and sought user feedback and satisfaction using a standardized questionnaire.ResultsPreclinical data showed that the MPR was capable of bridging power outages and delivering a continuous flow of oxygen to a simulated patient. The MPR was then deployed for clinical testing in nine pediatric patients at Ahero and Suba Hospitals. Power was unavailable for 2% of the total time observed due to 11 power outages (median 4.6 min, IQR 3.6–13.0 min) that occurred during treatment with the MPR. Oxygen flowrates remained constant across all 11 power outages. Feedback on the MPR was uniformly positive; all respondents indicated that the MPR was easy to use and provided clinically significant help to their patients.ConclusionWe present a MPR oxygen delivery device that has the potential to mitigate power insecurity and improve the standard of care for hypoxemic pediatric patients in resource-limited settings.

Hospital El Salvador: a novel paradigm of intensive care in response to COVID-19 in central America

Hospital El Salvador: a novel paradigm of intensive care in response to COVID-19 in central America

Removal of Pollution by Intensive Aeration Technology for Landfill Leachate Treatment.

Background.Landfill leachate is a source of environmental pollution and a major concern for human health because it contains high concentrations of organic and inorganic contaminants.Objectives.The objective of the present study is to validate the efficiency of the forced aeration treatment technique, which consists of intensively injecting a continuous oxygen flow of 16.75 kg/m3/h for 30 days using a bubble air diffuser in a relatively small volume of 1 m3. The principle of the technique is essentially based on acceleration of the degradation of the effluent as well as reduction of the organic and nitrogenous matter contents.Methods. Forced aeration technology was used for the treatment of leachate from the Mohammedia-Benslimane landfill. The sample was treated by injecting a flow of oxygen to accelerate the biodegradability of the pollutants by the microorganisms.Results.The physicochemical characterization of the raw leachate at the inlet of the aeration tank showed high values for chemical oxygen demand (COD) (38,600 mg O2/l), biological oxygen demand (BOD5) (24,000 mg O2/l), and total Kjeldahl nitrogen (TKN) (5,932.45 mg/L). The proposed treatment technique allowed relatively high purification yields to be achieved, with abatement rates for the major elements COD, BOD5 and TKN of 73%, 98%, and 85%, respectively.Conclusions.The treatment of leachate by intensive aeration technology reduces considerably the pollutant load and achieves a high purification yield.Competing Interests.The authors declare no competing financial interests.

Feasibility and Efficacy of Pulsed-Dose Oxygen Delivery During Noninvasive Ventilation.

It is difficult to apply noninvasive ventilation (NIV) simultaneously with pulsed-dose oxygen delivery. We evaluated the feasibility and efficacy of pulsed-dose oxygen delivery during NIV. A bench study was conducted using a simulated lung during NIV, with a breathing frequency of 10 or 20 breaths/min and 3 oxygen injection sites (site A on face mask, site B proximal to face mask, and site C at the ventilator outlet) with continuous flow oxygen delivery of 1, 3, or 5 L/min) or pulsed-dose oxygen delivery (numerical settings of 1, 3, or 5 representing the oxygen pulse characteristics). [Formula: see text] under different experimental conditions and the influence of mode of oxygen delivery on NIV (compared to baseline and continuous flow oxygen delivery vs pulsed-dose oxygen delivery) were compared. In the clinical study, we enrolled 10 subjects with COPD exacerbation who received NIV with either continuous flow oxygen delivery or pulsed-dose oxygen delivery. Under the same targeted pulse oxygen saturation (88-92%), the numerical settings of different modes of oxygen delivery were titrated, and the clinical parameters during the different modes of oxygen delivery were compared. In the bench study, the ratio of the [Formula: see text] with pulsed-dose oxygen delivery to the [Formula: see text] with continuous flow oxygen delivery at the same numerical setting was 0.94 ± 0.15. The oxygen injection site had a significant influence on [Formula: see text] in pulsed-dose oxygen delivery or continuous flow oxygen delivery mode (P < .05). Pulsed-dose oxygen delivery worked effectively with the ventilator, as demonstrated by the fine synchronization in the breathing cycle of the ventilator, the simulated lung, and the pulsed-dose oxygen delivery. When compared with each other or compared to the baseline individually, pulsed-dose oxygen delivery and continuous flow oxygen delivery showed no clinically important effects on NIV (all P > .05 or changes < 10%). In the clinical study, the mean numerical settings for pulsed-dose oxygen delivery and continuous flow oxygen delivery modes after titration were 2.68 ± 0.32 and 2.31 ± 0.56 L/min, respectively. There was no significant difference between continuous flow oxygen delivery and pulsed-dose oxygen delivery (P > .05). Integration of pulsed-dose oxygen delivery into NIV could achieve efficacy similar to that achieved with continuous flow oxygen delivery.

Design of a Sustainable Automated Solar Powered Aquaponic System – Case of St Peter’s Mbare Secondary School – Harare, Zimbabwe

As population is growing, limitations on natural resources is also increasing. Consequently, there is a need to use natural resources such as water and land efficiently as much as possible. Traditional farming methods depend on reliable rainfall. In the realm of rainfall variability, other methods are needed to avert famine. Currently, in Zimbabwe, aquaponic systems are being considered as the best way to avert famine. This study was done at St. Peter’s Mbare Secondary School where there is complete and operational aquaponic system. The system basically faced the frequent power outages leading to interruptions in running of pumps. This impacted continuous oxygen flow causing the fish dying. However, Zimbabwe has enormous potential of solar PV not yet exploited. The objective of this research was to harness solar energy and integrate it to traditional aquaponics thereby making the system sustainable and innovative (automated) supplied by a standalone PV system. A 1.6 kW solar PV array was sized to run an electrical load of 293.2 W meant of water pump, aerator and electronics devices. The system was automated using Arduino based system to monitor the pH, temperature and water flow velocity in the Aquaponic system. The designed system is scalable and would serve a model to be implemented in other localities.

RF Magnetron Sputtering Deposition of TiO2 Thin Films in a Small Continuous Oxygen Flow Rate

Rutile titanium oxide (TiO2) thin films require more energy to crystallize than the anatase phase of TiO2. It is a prime candidate for micro-optoelectronics and is usually obtained either by high substrate temperature, applying a substrate bias, pulsed gas flow to modify the pressure, or ex situ annealing. In the present work, we managed to obtain high enough energy at the substrate in order for the particles to form rutile TiO2 at room temperature without any intentional substrate bias in a continuous gas flow. The rutile TiO2 thin films were deposited by a reactive radiofrequency magnetron sputtering system from a titanium target, in an argon/oxygen gas mixture. Investigations regarding the film’s structure and morphology were performed by X-ray diffraction (XRD), X-ray reflectivity (XRR), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDAX), while the optical properties were investigated by means of ellipsometry.