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A reverse osmosis system driven by photovoltaic energy is an eco-friendly and sustainable way to produce freshwater in rural areas without connection to a power grid and with available brackish water sources. This paper describes a project where a photovoltaic-driven low-pressure reverse osmosis system (LPRO-PV) was designed, tested under laboratory conditions, and installed in Samalayuca, Chihuahua, Mexico, to evaluate the technical feasibility and social impact of this technology. The LPRO-PV system was tested with synthetic water with a salinity of 2921 ± 62.3 mg/L; the maximum freshwater volume produced was 1.8 ± 0.06 m3/day with a salinity value of 91 ± 1.9 mg/L. The LPRO-PV system satisfied the basic freshwater requirements for a local family of three members for one year, including the mobility-restriction period due to the COVID-19 pandemic. The social evaluation analysis reflects the importance of considering the technical aspects derived from the experimental tests, as well as the users’ perception of the performance and operation of the system. As a result of the implementation of this technology and the benefits described by the users, they committed to the maintenance activities required for the LPRO-PV system’s operation. This technology has great potential to produce fresh water in arid and isolated regions with high-salinity groundwater sources, thus fulfilling the human right to safe and clean drinking water.

This article reports a model regarding the structural equations of the impact of the planning phase and the benefits acquired in the implementation of the kanban system. It begins with a literature review of the activities of the planning phase, based on which a questionnaire was developed and applied in manufacturing companies in the state of Baja California, in the municipalities of Ensenada, Tijuana, Tecate, and Mexicali. The responses were obtained from 118 questionnaires and were validated by the Cronbach’s alpha index for internal validity and the R-squared index for predictive validity. A model of the structural equations of the planning phase was developed and validated through three latent variables, namely, human resources, preliminary analysis, and kanban integration, which correspond to 22 activities and one variable that integrate 11 operational benefits. The model shows six hypotheses to verify the causal relationships between these variables. Partial least-squares algorithms are used to validate the hypothesis, and the results indicate that the preliminary analysis is the basis for the success of the implementation of the kanban in the planning stage, through the application of activities, such as 5’s, value stream mapping (VSM), material handling, flow diagram, and visual aids with a sustainable approach, according to the efficient flow of materials and minimum downtime.

Spain has been pinpointed as one of the European countries at major risk of extreme urban events. Thus, Spanish cities pursue new urban plans to increase their resilience. In this scenario, experiences in the implementation of Sustainable Urban Drainage Systems (SUDS) have increased substantially. Nevertheless, few cities have developed a global urban strategy for SUDS, lacking, in many cases, a method to identify strategic areas to maximize their synergetic benefits. Furthermore, there is still a need for a holistic Multicriteria Decision Analysis (MCDA) framework that considers the four pillars of SUDS design. The city of Gijón, NW Spain, has been selected as a case study due to its environmental and climatic stresses. This research presents the methodology developed for this city, which aims to analyze the need for SUDS implementation throughout the identification of strategic areas. With this aim, a combination of Geographic Information System (GIS) software and the MCDA Analytical Hierarchical Process (AHP) were proposed. The results show the potential for SUDS’ implementation, according to nine criteria related to the SUDS’ design pillars. We found that the areas where the implementation of SUDS would bring the greatest functional, environmental and social benefits are mainly located in consolidated urban areas.

The world’s growing energy demand poses several concerns regarding the rational and efficient use of energy resources. This is also the case for many industrial processes, where energy losses and particularly thermal losses are common. Thermoelectric generators offer an alternative to address some of these challenges by recovering wasted heat and thereby increasing the overall efficiency of these processes. However, the successful operation of the thermoelectrical modules meant to carry this process is only possible when pairing these to an external control system; such a system plays an important role in predicting and operating such modules at its maximum power point. In this review paper, recent developments in the field of thermoelectric technology are discussed along with their mathematical models, applications, materials, and auxiliary devices to harvest thermal energy. Moreover, new advancements in phenomenological models are also discussed and summarized. The compiled evidence shows that the thermal dependence properties on the thermoelectric generator material’s modules and the mismatching thermal conditions play an important role in predicting power output in those systems, which prove the importance of including those parameters to enhance the accuracy of the energy production prediction. In addition, based on the evaluation of the mathematical models, it is shown that more studies are required to fill the gap between the current state-of-the-art of the technology and adjacent modeling techniques for the design and evaluation of thermal energy harvesting systems employing thermoelectric arrays under mismatching thermal conditions.

The increase of energy access to households has been a global priority. By 2018, 89.59% of the world population had access to electricity, while 97.26% of the persons living in urban areas (The Mexican Government reports it at 99.99%) had access. We must now move beyond access to electricity and address energy poverty in urban spaces. A household is energy poor when their inhabitants are incapable of securing proper domestic energy services. Several different methodologies were developed to measure energy poverty. The Multidimensional Energy Poverty Index (MEPI) by Nussbaumer has been successfully used in Africa and in Latin-America. The MEPI considers five dimensions: cooking, lighting, household appliances, entertainment/education and communication. We developed a Multidimensional Energy Deprivation Index (MEDI), based on MEPI. Thermal comfort has been included as sixth dimension, by considering the temperature of the region where the household is located. We found important differences between MEPI and MEDI for Mexico at the national level (urban-MEPI at 0.028 vs. 0.071 urban-MEDI, which implies a higher degree of energy poverty). Also, differences between geopolitical and bioclimatic regions were found. Having better ways to assess energy poverty in the urban context is a key factor to develop effective public policies that might alleviate it.

The building sector is considered a key area for sustainable development, due to the potential to reduce greenhouse gas emissions in the numerous economic activities that this sector involves. A low-cost lightweight cementitious composite consisting in perlite mortar was fabricated and evaluated. The thermal conductivity and heat capacity of the proposed composite were tested in the laboratory. The lightweight composite was integrated into a prototypical house and its thermal performance was tested for two different arid climates during a typical meteorological year. A techno-economic analysis of this integration was carried out, which showed the lightweight system integration could reduce the energy demand up to 10.3% due to the decreased use of heating and cooling systems. The CO2 emissions associated with electricity and gas use on cooling and heating systems could be reduced up to 10.9%.

Natural asphalts (NAs) can be an economical and environmental alternative in pavement construction. Most studies have investigated them as binder and asphalt mixture modifiers due to their high compatibility with conventional asphalts. In this article, some of the studies carried out on the use of NA in pavements are summarized and described in a chronological order. The main aspects described in the reviewed studies were the type of asphalt binder or modified mixture, the type and content of the modifier, the manufacturing processes of the asphalt or modified mixture, tests performed, and main results or conclusions. In general terms, NAs show better performance as binder and asphalt mixture modifiers in high-temperature climates. Additionally, they tend to improve water and ageing resistance. As main limitations, it is reported that NAs tend to negatively affect the workability and performance of asphalt mixtures in low-temperature climates. Finally, recommendations for future study topics are provided at the end of this paper.

In this paper, a methodology termed MODELI (methodology for the design of educational digital objects for indigenous languages) is presented for the development of digital learning objects (DLOs) for the Mixtec language, which is an indigenous Mexican language. MODELI is based on the spiral model of software development and integrates three important aspects for the analysis and design of DLOs: pedagogical, affective-emotional and technological-functional. The premise of MODELI is that the emotional aspect with the inclusion of cultural factors has an important effect on the learning motivation of indigenous users when interacting with the DLO. Principles of the visual, auditory (or aural), read/write, kinesthetic (VARK) model and Kansei engineering were considered for the inclusion of the pedagogical, emotional and technological-functional aspects within the spiral model for the development of MODELI. The methodology was validated with the development of a DLO for a previously unknown variant of the Mixtec language. Usability tests of the DLO built with MODELI evidenced an improvement on the learning motivation and the value of cultural identity of indigenous children. These results are important for the preservation of indigenous languages in Mexico, because most of them are partially documented, and there is social rejection of indigenous culture caused by discrimination of ethnic communities.