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In lunar and deep-space farming, saline stress (SS) induced by human urine in hydroponically grown vegetables constitutes one of the prime concerns in its utilization for plant nutrition. Therefore, an indoor hydroponic trial was performed to assess the effectiveness of foliar feeding of citric acid (CA, 50 µM as two sprays at 26 days and 38 days after germination using a common hand-held sprayer) and the control treatment (a standardized plant nutrient with 10% synthetic urine replacement and 50 mM NaCl-induced SS) for sugar beets. The response variables included vegetative growth traits of sugar beets, such as the height of plants and stem girth along with lengths and fresh weights of leaves, roots, and whole plants. The recorded findings demonstrated that at the fourth week of germination, CA foliar feeding did not produce a statistically significant impact on the leaf width and plant height of sugar beets. However, CA produced 17%, 14%, and 35% taller plants at the six, eight, and ten weeks of germination, respectively. Likewise, the control treatment recorded 32% and 30% smaller leaf widths of sugar beets compared to the CA foliar feeding treatment at the 8th and 10th weeks of germination, respectively. In addition, it was found that CA foliar feeding was effective in enhancing the stem length and root length by 16% and 38%, respectively compared to the control under SS. Moreover, CA foliar feeding enhanced stem diameter (26%) and root fresh weight (29%) compared to the control treatment. As far as leaf length and fresh weight along with whole plant fresh weight were concerned, foliar feeding of CA demonstrated its effectiveness by producing 32%, 21%, and 42% greater values, respectively compared to the control treatment. Therefore, CA foliar feeding could serve as a potent strategy to mitigate the deleterious effects of saline stress and boost the vegetative growth of hydroponically grown sugar beets. [ABSTRACT FROM AUTHOR] more...

A critical issue facing extraterrestrial expansion has always been long-term life support capabilities. The large energy requirements to move even small amounts of material from Earth necessitate the ability to reuse and recycle as much as possible, particularly waste. The weight of food supplies eventually starts to limit the length of the expedition. Hydroponic growth systems offer the ability to grow plants, and with them, a miniature ecosystem. This offers the ability to repurpose both carbon dioxide and waste salts such as ammonia and other compounds, such as those found in urine. A major issue facing hydroponic systems is the need to provide a stable water-based nutrient stream. Direct contact membrane distillation (DCMD) was tested for viability as a method of re-concentrating and stabilizing the nutrient-rich water stream. Polytetrafluoroethylene (PTFE)- and polyvinylidene (PVDF)-based polymer hydrophobic membranes were used to separate solutes from water. The DCMD method was tested with the feed stream operating at temperatures of 50 °C, 65 °C, and 80 °C. The results were analyzed using UV-Visible spectroscopy to determine concentrations. The benefits and limitations of the PTFE and PVDF membranes in DCMD were compared. The larger-pore PTFE membranes concentrated solutions effectively at 80 °C, while the PVDF membranes removed more water at lower temperatures, but permitted detectable phosphate ion leakage. Adjusting temperature and flow rates can help maintain stable ion and water transfer, benefiting hydroponic systems in achieving reliable nutrient levels. [ABSTRACT FROM AUTHOR] more...

Direct Contact Membrane Distillation (DCMD) uses low heat sources to separate water from urea, which was then used as a plasticizer in regolith-based cement to make it more workable. The work investigated separating potable water and urea from artificial urine using DCMD and then characterizing the products. Water was successfully separated from the artificial urine solution as characterized by density, conductivity, pH, and substance concentrations. The concentrated urine solution was used in regolith-based cement cured under vacuum at temperatures that simulated temperatures that would be expected in construction on the Moon. Workability and other properties were improved by replacing water with concentrated urine solution in the mix. [ABSTRACT FROM AUTHOR] more...

Appropriate nutrient sources and optimized doses of plant nutrients for space and lunar farming have remained key challenges prompting investigations to sort out biologically viable options including human urine. Therefore, a trial was performed to compare the hydroponic growth of sugar beets using a standard nutrient solution and the same nutrient solution with a 10% replacement of an artificial urine solution that had been concentrated using direct contact membrane distillation (DCMD). The response variables included yield-contributing traits and root parameters (plant height, stem diameter, length and fresh weight of leaf and root, whole plant fresh weight), along with beet characteristics (diameter, length, and fresh weight at harvest). The results revealed that 10% synthetic urine treatment produced significantly taller plants (33%, 3%, and 8% at the 4th, 6th, and 10th week after sowing, respectively) and recorded 52% and 40% greater leaf width at the 4th and 6th weeks, respectively, compared to the control. In contrast, 10% replacement with synthetic urine in the nutrient performed statistically below par compared to the control treatment by producing 9% and 17% lower leaf width at the 8th and 10th weeks, respectively. Additionally, at the harvest, 10% synthetic urine treatment gave taller plants with greater stem length and root length (2.3%, 8.6%, and 59%, respectively) than the control. Moreover, the replacement treatment remained superior by showing higher root weight and stem diameter at harvest but performed below par compared to the control in leaf width and whole plant fresh weight. At harvest, both treatments remained statistically non-significant in terms of beet length, however the control surpassed synthetic urine treatment by yielding 37% and 103% higher width and fresh weight of beets, respectively. Based on recorded findings, it may be inferred that synthetic urine holds potential as a valuable plant nutrient source for producing sugar beets in an indoor hydroponic system, though not comparable in some respects with the control (standardized plant nutrient medium) for some plant measurements. [ABSTRACT FROM AUTHOR] more...

Sustainable structures are an important area of research, particularly for anticipated extended human presence on the Moon or Mars. Persistent human presence on the Moon will require building materials that are already present at the site to construct bases. The high cost associated with reinforcing metal (rebar) in mission payloads necessitates the exploration of alternative reinforcement methods for sustained lunar bases. Human hair is strong in tensile strength and will become available in any long-term mission. By using otherwise wasted hair instead of heavy metal, mission payloads and costs could be lowered. Concrete workability, compressive strength, and porosity were measured for a series of different cement compositions. These compositions consisted of combinations of Ordinary Portland Cement (OPC), lunar regolith, deionized (DI) water and human hair. Increased workability and porosity were found for increasing hair concentrations. Compressive strength slightly decreased with increased hair concentration. [ABSTRACT FROM AUTHOR] more...

The development of each nation is evaluated by its infrastructure, and each nation is competing with the others in infrastructure advancement, especially in the construction of roadways, since they play a vital role in the economic and social development of the nation. The conventional materials used for road construction are concrete and asphalt, which pose significant environmental challenges. This research gives insight into the potential of fly ash (FA) and corn stover (CS) in synthesizing geopolymer, as an alternative material for the construction of roads. This study examines the impact of three FA and CS mixture percentages and the particle size of CS on the compressive strength and porosity of geopolymer. The results indicate that incorporating larger amounts of CS in fly ash-based geopolymer may decrease the compressive strength of the geopolymer. Smaller CS particle sizes also tend to lead to lower compressive strength. Porosity of the geopolymer tended to increase with the incorporation of higher percentages of CS, particularly for smaller corn stover sizes. As a fine aggregate replacement for geopolymer, CS incorporation has the potential to reduce mined aggregate obtained from a process that harms the environment. [ABSTRACT FROM AUTHOR] more...

Phase behavior, density, viscosity, conductivity, pH, and surface tension were measured, and FTIR was performed for a series of mixtures of sugar (glucose, fructose, xylose, and sucrose), water, and choline chloride (ChCl) at specific molar ratios. These mixtures, called sugar-based natural deep eutectic solvents (NADESs), were investigated as a function of temperature. Contact angle measurements indicated that NADES exhibited slightly lower wettability but higher surface tension than water. Temperature was found to greatly impact density, viscosity, and conductivity. The optimum water molar ratio for lower viscosity was found at ratios higher than those reported in the literature, indicating that the NADES investigated may have industrial process applications. [ABSTRACT FROM AUTHOR] more...