Kg Of Oxygen Research Articles

Innovative multi-generation system producing liquid hydrogen and oxygen: Thermo-economic analysis and optimization using machine learning optimization technique

This research investigates the multi-objective optimization of a geothermal-driven multi-generation system designed to produce liquid hydrogen and oxygen as its primary outputs. The system incorporates a Proton Exchange Membrane (PEM) Electrolyzer alongside a modified ejector-based Organic Rankine Cycle to generate the required Energy (heating bar, cooling bar, electricity and hydrogen). Case studies were conducted in three distinct locations: Zanjan in Iran, Aarhus in Denmark, and San Bernardino in the United States, utilizing actual geological and meteorological data for accuracy. Simulations were executed applied Engineering Equation Solver & optimization of the system was carried out to enhance performance by focusing on the objective functions of system exergy efficiency and cost reduction. This was accomplished by utilizing response surface methodology (RSM) along with Minitab software (MS).To optimize the system, six decision variables were identified as critical parameters influencing performance. The optimization results indicated that the system can achieve an exergy efficiency of 53.74 % while maintaining a cost rate of $31.56 per hour. The overall cost rate for the geothermal system was determined to be $54.50 per hour, with $10.10 per hour allocated to hydrogen production and $44.40 per hour to electricity generation. Site-specific analyses highlighted San Bernardino as the most favorable location for implementing this system, projecting an annual production of 90.8 tons of liquid hydrogen and 208.3 kg of oxygen. In August, the geothermal system in San Bernardino can produce up to 7691.6 kg/h of liquid hydrogen, while in December, production decreases to 7402.8 kg/h, marking the lowest output for the year. In contrast, Zanjan and Aarhus demonstrated lower production capacities, underscoring the system's feasibility as dependent on site-specific conditions.

Review of Studies on Performance of Dowel Connections Loaded Perpendicular to Grain

Wood as a sustainable building material demonstrates significant advantages in terms of environmental protection, economy and functionality. Studies showed that adding 1.0m3 of wood could absorb 1.0kg of carbon dioxide, produce 730kg of oxygen, and fix 270kg of carbon, which plays an important role in ecological environment protection. In addition, in addition, wood has good thermal insulation performance, can adjust indoor humidity, beneficial to human health.China's wooden structure architecture has a long history. As an important technology in China's traditional architecture, mortise and tenon connection technology constitutes an important part of Chinese traditional architectural heritage through the insertion of wood components. As a prefabricated building form, modern wood structure has a history of more than 100 years in developed countries. The main forms include heavy wood structure, light wood structure, square wood wood structure and wood mixed structure. In recent years, wood structure architecture has attracted wide attention in scientific research and application in China. Whether for new construction or large-scale reconstruction projects, wood structure buildings are widely adopted because of their design flexibility, high strength and aesthetics, as shown in Figure 1.1. Modern wood structure buildings show the advantages of energy conservation and environmental protection, good earthquake resistance, convenient construction and safety and comfort, and its development is fully in line with the national sustainable development strategy.

Integrating solar chimney power plant with electrolysis station for green hydrogen production: A promising technique

This paper explores the use of Solar Chimney Power Plants (SCPPs) for the production of green hydrogen as a means to store excess electrical energy generated from renewable energy resources (RESs). The proposed structure produces electrical energy and distilled water by heating the air under the SCPP. The electrolyzer is integrated into the seawater pool and installed at the solar chimney's base. The weather conditions at the proposed location of the SCPP including solar radiation, temperature, humidity, and wind speed, are analyzed to assess their impact on the performance of the SCPP. The potential applications and economic feasibility of the SCPP are discussed, considering its contribution to renewable energy generation and the benefits of hydrogen as a clean energy carrier. The results show that solar radiation levels and favorable temperature profiles play an important role in the performance of the SCPP. The SCPP could produce 380,263 kW h of electrical energy and 139,443 tons of distilled water annually. The results also showed that the SCPP could produce 13,000 kg of green hydrogen and 173,224 kg of oxygen annually. The revenue generated from the production of H2 and O2 has improved the levelized cost of energy (LCOE) for the SCPP to 0.51 $/kWh and made it compete with other energy production facilities. Monthly variations in electrical energy, H2, O2, and distilled water production, highlight the dependence of hydrogen production on solar intensity and temperature. Overall, the research demonstrates the potential of SCPPs and hydrogen production as a sustainable and efficient solution for storing and utilizing excess renewable energy.

Combining renewable sources towards negative carbon emission hydrogen

Multi-energy systems that combine different energy sources and carriers to improve the overall technical, economic, and environmental performance can boost the energy transition. In this paper we posit an innovative multi-energy system for green hydrogen production that achieves negative carbon emissions by combining bio-fuel membrane-integrated steam reforming and renewable electricity electrolysis. The system produces green hydrogen and carbon dioxide, both at high purity. We use thermo-chemical models to determine the system performance and optimal working parameters. Specifically, we focus on its ability to achieve negative carbon emissions.The results show that in optimal operating conditions the system can capture up to 14.1 g of CO2 per MJ of stored hydrogen and achieves up to 70% storage efficiency. Therefore, we prove that a multi-energy system may reach the same efficiency of an average electrolyzer while implementing carbon capture. In the same optimal operating conditions the system converts 7.8 kg of biogas in 1 kg of hydrogen using 3.2 kg of oxygen coming from the production of 6.4 kg of hydrogen through the electrolyzer. With such ratios we estimate that the conversion of all the biogas produced in Europe with our system, could result in the installation of additional dedicated 800 GWp - 1280 GWp of photovoltaic power, or of 266 GWp - 532 GWp of wind power, without affecting the distribution grid and covering yearly the 45% of the worldwide hydrogen demand while removing from the atmosphere more than 2% of the European carbon dioxide emissions.

Thermochemical process and compact apparatus for concentrating oxygen in extraterrestrial atmospheres: a feasibility study

The Martian atmosphere contains 0.16% oxygen, which is an example of an in-situ resource that can be used as precursor or oxidant for propellants, for life support systems and potentially for scientific experiments. Thus, the present work is related to the invention of a process to concentrate oxygen in the oxygen-deficient extraterrestrial atmosphere by means of a thermochemical process and the determination of a suitable best-case apparatus design to carry out the process. The perovskite oxygen pumping (POP) system uses the underlying chemical process, which is based on the temperature-dependent chemical potential of oxygen on multivalent metal oxide, to release and absorb oxygen in response to temperature swings. The primary goal of this work is therefore to identify suitable materials for the oxygen pumping system and to optimize the oxidation–reduction temperature and time, required to operate the system, to produce 2.25 kg of oxygen per hour under the Martian most-extreme environmental conditions and based on the thermochemical process concept. Radioactive materials such as 244Cm, 238Pu and 90Sr are analyzed as a heating source for the operation of the POP system, and critical aspects of the technology as well as weaknesses and uncertainties related to the operational concept are identified.

The Use of Enhanced External Counterpulsation in Complex Medical Rehabilitation of Stable Coronary Heart Disease in Patients Permanently Residing in Humid Subtropics

Aim. To study the dynamics of overall tolerance in patients in the early recovery period of ischemic stroke (IS) with mild and moderately severe paresis, to evaluate the effect of aerobic training in this group of patients on exercise tolerance during inpatient treatment as of Compulsory Medical Insurance (CMI). Material and methods. The first group of 30 patients were examined (17 women, 13 men, the average age – 60,6±6,45 years old) during the 4-6 week of IS. Total points of the FIM scale were 118±5,2 /121,8±4,5. The second group- control group consisted of 30 patients with chronic cerebral ischemia (CCI). The following were mainly dominated among the vascular risk factors in both groups of patients: atherosclerosis of brachiocephalic artery of various degrees of severity poorly controlled arterial hypertension, smoking, dyslipidemia. Physical exercise tolerance was assessed by cardiopulmonary testing on a bicycle ergometer using the Quark CPET spiroergometer system from COSMED (Italy). The peak oxygen consumption (VO2 peak), the maximum load performed in metabolic units (MET), the percentage of the proper maximum oxygen consumption (% pred VО2 peak) with constant ECG monitoring, blood pressure during the exercise test were evaluated. Patients with stroke received aerobic training during rehabilitation treatment – 10-12 sessions according to the target indicators. Results and discussion. The minimum required values of VO2 peak to provide an active daily life equals on average 15 -18 ml/min *kg of oxygen. Analysis of the results of our study showed a decrease in the VO2 peak in group 1 of stroke patients to 13.22 ± 3.32 ml/min * kg. The VO2 peak at stroke is only 54.96% ± 12.82 of the proper average values of VO2 and corresponds to 3.73 ± 0.92 MET. The results of the study confirm a very low level of exercise tolerance in the stroke group, which is significantly lower than in the CCI group (VO2 peak is 19.43 ± 4.77 ml/min * kg, which is 83.96 ± 12.93% of the proper average values and corresponds to 5.74 ± 1 .65 MET). The results of the study confirm a very low level of exercise tolerance in the stroke group, which is significantly lower than in the CCI group (VO2 peak is 19.43 ± 4.77 ml/min * kg, which is 83.96 ± 12.93% of the proper average values and corresponds to 5.74 ± 1.65 MET). Cardiopulmonary testing showed the absence of reliable dynamics of VO2 peak (p=0.29) and MET (p= 0.4) at the end of the rehabilitation course. A significant increase in VO2 peak was observed only in some patients who reached a load intensity level of 70% or more of the peak heart rate during training. Later a control study was conducted among 16 patients of the stoke group after 6 months. Cardiopulmonary testing showed the absence of reliable dynamics of the studied parameters in the absence of cardio training ambulatory. Our study of the patients’ with stroke condition in dynamics showed that there was no possibility of spontaneous (without aerobic exercise) restoration of exercise tolerance. Conclusion. In the early recovery period of IS, patients have a persistent long-term decrease of overall tolerance. Aerobic exercises have shown safety and good tolerance in IS rehabilitation programs. Aerobic exercises should be long-term, begin in a hospital and continue during ambulatory treatment. The intensity of training is a key parameter in the adjustment of Aerobic exercises for the patients with IS.

Estimating the scale of Space Resource Utilisation (SRU) operations to satisfy lunar oxygen demand

The production of oxygen from lunar regolith is analogous to metal production from ore in a terrestrial mine. The process flowsheets both include excavation, haulage and beneficiation of the regolith or ore to provide the feedstock for the chemical extraction of oxygen or metal. The production rate of oxygen depends on the mass rate of regolith treated and the efficiency of converting the regolith to oxygen. To date, the development of Space Resource Utilisation (SRU) has been concerned with the technological development of the process, particularly the excavation and oxygen extraction. However, the required operating mass rates of the mine operation and the oxygen extraction stage have not been considered in any great detail.Previous estimates of mining scale for lunar oxygen production are reviewed, and converted to a comparable regolith mining rate of kg/h. Beneficiation of the regolith before oxygen extraction is considered, and the effects of pre-sizing and removal of a specific component, agglutinates, are considered. The oxygen yield and operational availability are also included. It is estimated that the minimum mining rate to produce 1000 kg of oxygen per annum is at least five times higher than previous estimates, 30 kg/h, for equivalent efficiency assumptions.Monte-Carlo simulations were performed for statistical confidence in the estimates of the mining mass rate and the required oxygen extraction feedstock rate. To be 95% confident that the 1000 kg/y O2 will be met, the designed mining rate should be at least 65 kg/h, and the beneficiated feedstock rate 16 kg/h.This study has revised and increased the estimate of the lunar regolith mining scale required for the production of a given amount of oxygen. It has also estimated the mass rate of feedstock required for oxygen extraction, if the regolith is first beneficiated.The findings have a significant impact on the practical implementation of lunar mining and oxygen extraction, particularly the process design and whether the operation will be by batch- or continuous processing. The mass scale and beneficiation approaches bring terrestrial mining and processing concepts to SRU, and for the first time estimates the effect that regolith beneficiation and uncertainty have on the estimated scale of both the mining and extraction operations.

Design and automation of a solar-powered floating-type aeration system (SPFTAS) for fish ponds

Aeration helps improve water quality and make it favorable to fish. SPFTAS was designed based on the environment and characteristics of freshwater ponds. SPFTAS consist of floating platform, power source, sensors, signaling and aeration system. It functions to disperse and increase dissolved oxygen (DO). It possessed capability to monitor real time condition of water, store data and send it through short messaging service (SMS). The SPFTAS oxygen transfer rate was 0.07 kg of oxygen using four diffusers and the standard aeration efficiency of 0.2710 kg oxygen/hp-hr. The standard oxygen transfer efficiency was 0.36 at 18 kg of oxygen transferred. SPFTAS increased DO level to 1.32 ppm and rated highly effective during the test. DO levels using 1, 2, 3 and 4 diffusers at different depths, distances and time results were significantly different. The DO level using different diffusers at time intervals was highest at 7.16 ppm in three hours operation. The total cost of automated SPFTAS was ₱ 170, 385.75. The cost analysis of using the machine indicated a breakeven point of 1, 440 hours per year. The annual operation expected save ₱ 32, 737.39 and expected recover the investment in 5.33 years. Finally, machine was found beneficial to increase DO concentration in fishponds.

INVESTIGATION OF THE CHANGE OF CHEMICAL COMPOSITION OF CHROMIUM BORIDE BY THE REFINING, STORAGE AND HEATING IN THE AIR

The investigation of the change of chemical composition of the nanopowder of chromium boride CrB2 by the refining, storage and heating in the air is investigated. The conditions of effective refining of chromium boride from free boron, carbon and chromium, including consistently held alkaline (NaOH) and acid (HCl) treatment are identified. The interaction of chromium boride with atmospheric gases (oxygen and moisture), taking place on the adsorption-diffusion mechanism and accompanied by a significant increase in oxidation in the first 24 hours is studied. It is established that with increasing of the particle size from 26 to 75 nm, the value of oxidation is changed from 17,01·10–7 to 10,82·10–7 kg of oxygen ∙ m–2 of surface of the powder. The analytical dimensional dependence is received for oxidation. The temperature of the beginning of oxidation in the air depends on the level of dispersion and it is 763 К for the nanopowder and 793 K for micropowder.

Evaluation of laboratory-scale in-vessel co-composting of tobacco and apple waste

Efficient composting process requires set of adequate parameters among which physical–chemical properties of the composting substrate play the key-role. Combining different types of biodegradable solid waste it is possible to obtain a substrate eligible to microorganisms in the composting process. In this work the composting of apple and tobacco solid waste mixture (1:7, dry weight) was explored. The aim of the work was to investigate an efficiency of biodegradation of the given mixture and to characterize incurred raw compost. Composting was conducted in 24L thermally insulated column reactor at airflow rate of 1.1Lmin−1. During 22days several parameters were closely monitored: temperature and mass of the substrate, volatile solids content, C/N ratio and pH-value of the mixture and oxygen consumption. The composting of the apple and tobacco waste resulted with high degradation of the volatile solids (53.1%). During the experiment 1.76kg of oxygen was consumed and the C/N ratio of the product was 11.6. The obtained temperature curve was almost a “mirror image” of the oxygen concentration curve while the peak values of the temperature were occurred 9.5h after the peak oxygen consumption.

NASA's biomass production chamber: A testbed for bioregenerative life support studies

The Biomass Production Chamber (BPC) located at Kennedy Space Center, FL, USA provides a large (20 m 2 area, 113 m 3 vol.), closed environment for crop growth tests for NASA's Controlled Ecological Life Support System (CELSS) program. Since the summer of 1988, the chamber has operated on a near-continuous basis (over 1200 days) without any major failures (excluding temporary power losses). During this time, five crops of wheat (64–86 days each), three crops of soybean (90 to 97 days), five crops of lettuce (28–30 days), and four crops of potato (90 to 105 days) were grown, producing 481 kg of dry plant biomass, 196 kg edible biomass, 540 kg of oxygen, 94,700 kg of condensed water, and fixing 739 kg of carbon dioxide. Results indicate that total biomass yields were close to expected values for the given light input, but edible biomass yields and harvest indices were slightly lower than expected. Stand photosynthesis, respiration, transpiration, and nutrient uptake rates were monitored throughout growth and development of the different crops, along with the build-up of ethylene and other volatile organic compounds in the atmosphere. Data were also gathered on system hardware maintenance and repair, as well as person-hours required for chamber operation. Future tests will include long-term crop production studies, tests in which nutrients from waste treatment systems will be used to grow new crops, and multi-species tests.

On the problem of the Martian atmosphere dissipation: Phobos: 2 TAUS Spectrometer results

The measurements of proton spectra obtained by the TAUS spectrometer on board the Phobos 2 spacecraft in elliptical orbits near Mars are presented. A strong deceleration of the solar wind upstream of the Martian bow shock was revealed. It can be caused by the mass loading of the plasma flow by ions originating from the hot oxygen/hydrogen corona of Mars and/or by protons specularly reflected from the bow shock. In the first case the deceleration of the solar wind by about 100 km/s implies that the hot oxygen corona of Mars could be several times denser than it was anticipated to be (at least during the observation period that was close to solar cycle maximum). Furthermore, the loss of planetary oxygen through the corona appears to be the main process of oxygen loss from Mars. The upper limit of loss rate for such a process is determined to be 1026 oxygen atoms or 2.5 kg of oxygen per second.

Light-enhanced convective throughflow increases oxygenation in rhizomes and rhizosphere of Phragmites australis (Cav.) Trin. ex Steud.

The convective throughflow of gases found recently in Phragmites australis increased with increasing fluxes of photosynthetically active radiation. Despite this, the oxygen in the venting gases remained lower than in air and the convection is thought to depend mainly on a humidity-induced diffusion of atmospheric gases across the leaf sheaths. When convection was prevented, and aeration was dependent entirely upon diffusion, no photosynthetic enhancement of rhizome and root aeration could be detected. In terms of oxygen transport, rapid rates of convection were much more effective than diffusion and substantially enhanced the entry of oxygen into the rhizome system. This resulted in large increases in the efflux of oxygen into the rhizospheres of basal laterals and apical and sub-apical regions of the adventitious roots. This effect was attributed to a greater diffusion of oxygen from rhizome to root. Substantial diurnal fluctuations in rhizome oxygen regimes and in root oxygen efflux occurred. It is estimated that because of convection and diffusion, up to 0.31 kg of oxygen d-1 m-1 may enter the rhizome system of vigorous stands of Phragmites during summer months. By comparison, diffusion alone could be expected to supply less than 0.01 kg d-1 . Scanning electron micrographs of root-shoot junctions showed that the resistance to gaseous diffusion from rhizome to roots must be especially small in Phragmites.

Oxygen Transfer Calculations for a Tractor-Powered Paddlewheel Aerator

Standardized aeration tests were conducted for a tractor-powered paddlewheel aerator of the type often used for emergency aeration of fish ponds. The greatest oxygen transfer coefficient (30.0 hour−1) and oxygen transfer rate (35.1 kg of oxygen per hour) were obtained at 108 rpm (revolutions per minute) and 54 cm paddle depth. All trials at 108 or 128 rpm with paddle depths of 36 cm or more had oxygen transfer coefficients and rates greater than 20 hour−1 and 20 kg of oxygen per hour, respectively. There was good agreement between the size and shape of spray patterns and oxygen transfer coefficients and rates.