A molecular dynamics (MD) modeling and simulations approach has been rationally built and developed to study porous food systems constructed with amylose and dextran chains. The findings from our MD studies indicate that the presence of food macromolecules decreases the energetics of the water–water interactions for the nearby water molecules in the pore space, but provides additional water–macromolecule interactions that can significantly outweigh the partial loss of water–water interactions to make the adjacent water molecules strongly bound to the food macromolecules so that the water activity and water removal rate are decreased as dehydration proceeds and, thus, the dehydration energy requirement would be increased. The effects of pore structures are greater in systems with higher densities of food macromolecules, smaller in size pores, and stronger water–macromolecule interactions. Dehydration of food materials can thus be reasonably expected to start from the largest pores and from the middle of the pores, and to have non-uniform water removal rates and non-planar water–vapor interfaces inside individual pores as well as across sections of the food materials. The food porous structures are found to have good pore connectivity for water molecules. As dehydration proceeds, water content and the support from water–water and water–macromolecule interactions both decrease, causing the food porous structures to adopt more compact conformations and their main body to decrease in size. Dehydration in general also reduces pore sizes and the number of pore openings, increases the water–macromolecule interactions, and leads to the reduction of the overall thermal conductivity of the system, so that more energy (heat), longer times, and/or greater temperature gradients are needed in order to further dehydrate the porous materials. Our thermodynamic analysis also shows that the average minimum entropy requirement for food dehydration is greater when the water–macromolecule interactions are stronger and the food macromolecular density is higher. The importance of the physicochemical affinity of food molecules for water and of the compatibility of the resultant porous structures with water configurational structures in determining food properties and food processing through the water–macromolecule interactions, is clearly and fundamentally verified by the results and discussion presented in this work.

Water, energy, and food are essential for human well-being and for sustainable development. Water is required in almost all types of electricity generation and it is highly consumed in food production. Cities, industry, and crop production have increased their needs for water, energy and land resources, and at the same time, they are facing problems associated with the environmental degradation and, in some regions, resource scarcity. This paper proposes a multiobjective optimization model for the design of a water distribution network from a water–energy–food nexus point of view. Additionally, crop production and cost relationships are integrated to account for the water and energy requirements in the agricultural sector. The economic objective is the maximization of annual gross profit, which accounts for the water, energy and food production; the environmental objective establishes the minimization of overall greenhouse gas emissions, and the social objective is the maximization of the number of jobs. In this paper, because the objectives are opposites, a multistakeholder assessment is proposed in order to analyze and quantify the relationship of the water–energy–food nexus to assess synergies that improve the decision-making process. The mathematical model was applied to a case study located in the Sonoran Desert in Mexico, in which, a series of scenarios were solved to illustrate the capabilities of the proposed optimization approach. The results show strong trade-offs between the considered objectives as well as the quantification of the water–energy–food nexus.

Pressures from growing demands and shrinking supplies have reached a critical junction in major global resources, particularly water, energy, and food (WEF). Recognizing the complex interaction across those highly interconnected resources, the nexus concept evolved to boost efficiencies across all nexus pillars. Several modeling efforts tried to capture the complexity of this problem, but most attempts captured only one or two nexus pillars, remained localized to fixed case-studies or applications, or used simulations to assess pre-defined scenarios rather than solving for optimum solutions under defined objective function and constraints. Here, we present an optimization model for water, energy, and food nexus resource management and allocation at a regional scale. The model was successfully validated using a hypothetical case study to test its efficiency under several resource availability scenarios and different policy targets. The results enhanced the understanding of the interlinkages among the nexus sectors by demonstrating the sensitivity of the WEF nexus to adopted strategies. For example, imposing food variety constraints changed water consumption by an order of magnitude and more than doubled energy requirements. Moreover, adopting renewable energy may cause increased demands for land, but can significantly cut CO₂ emissions. The model serves as an effective decision-making tool that enables policy makers to assess multiple WEF sources and recommends the optimum resource allocation under various policy, technology, and resource constraints.

Chukars (Alectoris chukar) and Sand Partridges (Ammoperdix heyi), two ground—dwelling phasianids, are permanent residents of the Negev desert and are sympatric over much of their ranges. Sand Partridges (body mass = 150—250 g), however, inhabit only arid and very arid areas, whereas Chukars (mb = 350—600 g) are widely distributed and inhabit deserts only at the margins of their ranges. We compared some of the desert adaptations of these phasianids by measuring the seasonal field metabolic rates (FMR) and water influxes (using doubly labelled water), diet selection, and food requirements of free—living Chukars and Sand Partridges at a site where both species occurred. Both species showed adaptation in the form of low energy metabolism, which ranged from 43 to 81% of that expected for birds of similar body mass. During summer, Sand Partridges had lower energy expenditures (5.47 kJ°g— ⁰ . ⁶ ¹°d— ¹) and water influxes 72.3 mL°kg— ⁰.⁷ ⁵°d— ¹) than did Chukars (6.42 kJ°g— ⁰ . ⁶ ¹°d— ¹ and 93.5 mL°kg— ⁰ . ⁷ ⁵°d— ¹, respectively), indicating more pronounced adjustments to arid conditions in the desert specialist. However, both species obtained more than half of their water influx in summer by drinking. Their summer diet was relatively dry, consisting mainly of seeds (80%) along with some green vegetation (18%) and, in Chukars, occasional arthropods. This situation changed abruptly after winter rains, which induced germination and reduced the availability of seeds. Chukars were unable to maintain energy balance in the face of low ambient temperatures and a diet (90% green vegetation) that contained much water but comparatively little energy, and they mobilized fat reserves to meet energy requirements. Most Sand Partridges left the study area after winter rains, apparently migrating to the lower elevation, warmer, and drier Arava (part of the Rift Valley). The winter rainy season appears to be the most stressful time of the year for both species. The adaptations to hot, dry conditions possessed by Sand Partridges may be accompanied by constraints on their abilities to cope with cool, wet conditions, and this may restrict them to arid and very arid habitats.

An increasing world population is projected to increase water, energy and food requirements, three vital resources for humankind. Projected climate change impacts will aggravate water availability, as well as flood risks, especially in urban areas. Nature-based solutions (NBS) have been identified as key concepts to defuse the expected tensions within the Water-Energy-Food (W-E-F) nexus due to their multiple benefits. In this paper, the authors outlined the theories and concepts, analyzed real-life case studies, and discussed the potential of NBS to address the future W-E-F nexus. For this purpose, we performed a systematic literature review on the theories of NBS that address the W-E-F nexus, and we summarized 19 representative real-life case studies to identify the current knowledge gaps and challenges. The quantitative and qualitative data was used to differentiate and discuss the direct and indirect potential benefits of NBS to the W-E-F nexus. The study further expanded on the challenges for the implementation of NBS and highlighted the growing possibilities in the context of circularity and the implementation of NBS in urban planning. It was concluded that the potential impacts of NBS on the W-E-F nexus have been identified, but the quantitative effects have not been analyzed in-depth. Moreover, indicators are mostly single-purpose and not multipurpose, as required to fully characterize the W-E-F nexus and circularity holistically. Overall, there is a need to adopt systemic thinking and promote the multipurpose design of NBS.

Using a multi-disciplinary approach, this paper integrated spatial analysis with agricultural and energy system modelling to assess the impacts of drought on crop water demand, water availability, crop yield, and electricity requirements for irrigation. This was done by a novel spatially-explicit and integrated water-food-energy nexus model, using the spatial climatic data generated by the mesoscale MESAN and STRÅNG models. In this study, the model was applied to quantify the effects of drought on the Swedish irrigation sector in 2013, a typical drought year, for a specific crop. The results show that drought can severely affect the crop yield if irrigation is not applied, with a peak yield reduction of 18 t/ha, about 50 % loss as compared to the potential yield in irrigated conditions. Accordingly, the water and energy requirements for irrigation to halt the negative drought effects and maintain high yields are significant, with the peaks up to 350 mm and 700 kWh per hectare. The developed model can be used to provide near real-time guidelines for a comprehensive drought management system. The model also has significant potentials for applications in precision agriculture, especially using high-resolution satellite data.