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Obtaining three-dimensional porous materials for different applications, has required complex methods to achieve the desired structure. Crumpling is an alternative to develop three-dimensional structures by randomly folding a sheet of material and offering a simple yet effective method to generate a unique, stiff and lightweight three-dimensional structure with minimal processing. Here, composite films made from polylactic acid (PLA), and exfoliated graphite (EG) were elaborated using solvent casting method. Additional pore formation is achieved adding calcium carbonate (CaCO3) particles as porogen. Films were characterized to corroborate the integration of exfoliated graphite to the PLA matrix as well as crystallinity changes due to EG and CaCO3 particles. Microscopy help to identify pore formation after CaCO3 remotion. Tensile tests, after increasing EG concentration in PLA, corroborate the formation of stiffer films with lower tensile strength, while pore formation decreased tensile strength and Young's modulus. After adding 0.5% wt. of EG, tensile strength partially recovered while Young's modulus was maintained. Composite films allowed to obtain 3D crumpled structures. Tests under compression help finding that 0.5% wt. of EG in PLA matrix resulted in a yield strength (26.6 MPa) and Younǵs modulus (32.5 MPa) increase, making necessary the application of considerable force to deform them.

In this contribution, the Jacobian analysis of a four-legged six-degrees-of-freedom decoupled parallel manipulator is carried out through the screw theory. As an intermediate step, for the sake of completeness the inverse/forward displacement analysis as well as the computation of the workspace of the robot are achieved by taking advantage of the decoupled orientation and position of the moving platform. Afterward, the input/output equation of velocity of the parallel robot is obtained by harnessing of the properties of reciprocal screw systems. Once the Jacobian matrices are identified and investigated, the analysis of singularities for the robot manipulator emerges as a natural application of the Jacobian analysis. Numerical examples are included with the purpose to show the practicality and versatility of the method of kinematic analysis. Furthermore, the numerical results obtained by means of the theory of screws are successfully verified with the aid of commercially available software like ADAMS.

Ohmic heating, also known as electrical resistance heating, is a novel process of pasteurization that has several advantages including homogeneous heating, low heating time, high inactivation of microorganisms, and organoleptic and nutritional properties. Furthermore, mathematical tools allow for quick and low-cost analysis of behaviors with various operating parameters. This study aimed to improve the ohmic pasteurization process of the mango pulp using computational fluid dynamics (CFD) and response surface methodology (RSM), using the experimental properties of mango pulp. The generated mathematical model is an accurate tool for predicting ohmic pasteurization behavior in an industrial environment; it presents a 4.4% standard deviation error in the experimental data. Furthermore, the arrangement and intensity of the added voltage analysis suggested operating variables with better pasteurization performance. Another observation was that the production speed was related to the voltage intensities of the inlet speed in a non-proportional manner. Additionally, operation at a low inlet velocity may be more susceptible to thermal damage, whereas operation at a high inlet velocity requires a particular proportion of voltage insertion to ensure adequate heat distribution.

Natural porous materials adjust their resulting mechanical properties by the optimal use of matter and space. When these are produced synthetically, they are known as mechanical metamaterials. This paper adds degrees of tailoring of mechanical properties by producing double levels of gradation in lattice structures via cross-section variation in struts in uniformly periodic lattice structures (UPLS) and layered lattice structures (LLS). These were then additively manufactured via material extrusion (ME) and vat photopolymerization (VP). Their effective mechanical properties under compressive loads were characterized, and their stiffness contrasted with finite element models (FEM). According to the simulation and experimental results, a better correlation was obtained in the structures manufactured via VP than by ME, denoting that printing defects affect the correlation results. The brittle natural behavior of the resin caused a lack of a plateau region in the stress–strain curves for the UPLS structures, as opposed to those fabricated with ME. The LLS increased energy absorption up to 244% and increased the plateau stress up to 100% compared to the UPLS. The results presented in this paper demonstrate that the mechanical properties of lattice structures with the same base topology could be modified by incorporating variations in the strut diameter and then arranging these differently.

Due to the high pollution caused by the consumption of energy from fossil fuels, governments have implemented policies that allow the transition to renewable sources, but this depends on many factors associated with the costs and attitudes of the population. This study examines the influence of perceived costs, benefits, and environmental concerns on the behavioral intentions toward renewable energy (RE) adoption in Ciudad Juarez, Mexico. A structural equation model is used to validate five hypotheses and information from 511 responses to a survey to explore how perceived costs (PCO) as an independent variable, perceived benefits (PBE), and environmental concerns (ECO) as mediators support intentions to adopt solar energy technologies. Findings reveal that PCO impacts PBE and ECO directly and influences behavioral intentions (BIN) indirectly. This underscores the importance of analyzing PCO in the context of developing countries due to the low per capita income. The study identifies ECO as the most significant factor affecting BIN and PBE as the primary influencer of ECO, suggesting that promoting the benefits of RE could enhance environmental concerns and, consequently, adoption intentions. Sensitivity analysis indicates the necessity of effectively disseminating cost-related information, as costs often overshadow perceived benefits. The findings advocate for clear communication regarding RE costs and benefits and the formulation of supportive policies to facilitate RE adoption in Mexico, highlighting the crucial role of comprehensive awareness strategies in improving public perception and acceptance of RE technologies, providing valuable insights for policymakers, stakeholders, and educators to promote sustainable energy practices.

Renewable energy, particularly geothermal energy, is on the rise globally. It has been demonstrated that recovering heat lost during geothermal cycles is essential due to the inefficiency of these cycles. This paper pproposes a combined power generation cycle using EES software to model a single-flash geothermal cycle, and a trans-critical carbon dioxide cycle. The study compares the system's performance during its "Without Economizer" and "With Economizer" operational stages. The impact of the economizer on the system's output metrics, including the net power output, energy efficiency, and exergy efficiency, was examined. The results show that the "With Economizer" system's net power output increased from 451.3 kW to 454 kW. The energy efficiency difference between the two systems is based on the first law of thermodynamics, where the value ofthe "Without Economizer" system is 6.036%, and the "With Economizer" system is 6.075%. The system without an economizer had an exergy efficiency value of 26.26%, whereas the system with an economizer reached 26.43%, based on the second law of thermodynamics. Installing the economizer increased the total economic cost rate of the system from 0.225M$/Year to 0.2294M$/Year, which increased the product cost rate from 15.82$/GJ to 16.02$/GJ.

Factors such as fossilisation, diversification of energy resources, sustainable development, and energy security are attracting global attention for the development and expansion of renewable energy sources. Environmental issues arising from fossil fuel consumption are being addressed, but concerns remain about the renewability and availability of new energy sources. Mexico is one of the ten countries in the exploitation of geothermal energy, with a history of approximately five decades. This study examines Mexico's five major geothermal fields: Cerro Prieto, Los Azufres, Los Humeros, Las Tres Vírgenes, and Domo San Pedro. Currently, Mexico is working with international geothermal companies. However, there are more power plants and substantial cooperation to obtain this energy for industry and homes. This study is focused on the potential of geothermal exploitation in Mexico and its position worldwide after the introduction of geothermal energy in Mexico. Next, five geothermal fields are introduced in Mexico, and the potential and capacities of each are discussed. Finally, the future energy scenarios in Mexico are reviewed, with an emphasis on geothermal energy .

The mosquito Aedes spp. holds important relevance for human and animal health, as it serves as a vector for transmitting multiple diseases, including dengue and Zika virus. The microbiome's impact on its host's health and fitness is well known. However, most studies on mosquito microbiomes have been conducted in laboratory settings. We explored the mixed microbial communities within Aedes spp., utilizing the 16S rRNA gene for diversity analysis and shotgun metagenomics for functional genomics. Our samples, which included Ae. aegypti and Ae. albopictus, spanned various developmental stages-eggs, larvae, and adults-gathered from five semiurban areas in Mexico. Our findings revealed a substantial diversity of 8,346 operational taxonomic units (OTUs), representing 967 bacterial genera and 126,366 annotated proteins. The host developmental stage was identified as the primary factor associated with variations in the microbiome composition. Subsequently, we searched for genes and species involved in mosquito biocontrol. Wolbachia accounted for 9.6% of the 16S gene sequences. We observed a high diversity (203 OTUs) of Wolbachia strains commonly associated with mosquitoes, such as wAlb, with a noticeable increase in abundance during the adult stages. Notably, we detected the presence of the cifA and cifB genes, which are associated with Wolbachia's cytoplasmic incompatibility, a biocontrol mechanism. Additionally, we identified 221 OTUs related to Bacillus, including strains linked to B. thuringiensis. Furthermore, we discovered multiple genes encoding insecticidal toxins, such as Cry, Mcf, Vip, and Vpp. Overall, our study contributes to the understanding of mosquito microbiome biodiversity and metabolic capabilities, which are essential for developing effective biocontrol strategies against this disease vector.

Due to the enormous diversity of non-culturable viruses, new viruses must be characterized using culture-independent techniques. The associated host is an important phenotypic feature that can be inferred from metagenomic viral contigs thanks to the development of several bioinformatic tools. Here, we compare the performance of recently developed virus-host prediction tools on a dataset of 1,046 virus-host pairs and then apply the best-performing tools to a metagenomic dataset derived from a highly diverse transiently hypersaline site known as the Archaean Domes (AD) within the Cuatro Ciénegas Basin, Coahuila, Mexico. Among host-dependent methods, alignment-based approaches had a precision of 66.07% and a sensitivity of 24.76%, while alignment-free methods had an average precision of 75.7% and a sensitivity of 57.5%. RaFAH, a virus-dependent alignment-based tool, had the best overall performance (F1_score = 95.7%). However, when predicting the host of AD viruses, methods based on public reference databases (such as RaFAH) showed lower inter-method agreement than host-dependent methods run against custom databases constructed from prokaryotes inhabiting AD. Methods based on custom databases also showed the greatest agreement between the source environment and the predicted host taxonomy, habitat, lifestyle, or metabolism. This highlights the value of including custom data when predicting hosts on a highly diverse metagenomic dataset, and suggests that using a combination of methods and qualitative validations related to the source environment and predicted host biology can increase the number of correct predictions. Finally, these predictions suggest that AD viruses infect halophilic archaea as well as a variety of bacteria that may be halophilic, halotolerant, alkaliphilic, thermophilic, oligotrophic, sulfate-reducing, or marine, which is consistent with the specific environment and the known geological and biological evolution of the Cuatro Ciénegas Basin and its microorganisms.

This study investigated the wind energy potential of Ciudad Juárez (Chihuahua, México) for a whole year. The viability of employing three small-scale wind turbine models, including the S-343, Bergey BWC Excel, and AOC 15/50, in Ciudad Juarez, located in the northern Mexican state of Chihuahua in Mexico, is studied in the first stage using RETScreen software. The performance of these three turbine models was subjected to sensitivity analysis in the following study stage using the three defined economic scenarios, assuming a 7% inflation rate, a 9% discount rate, a 7% fuel cost escalation rate, and a 20-year project duration. Finally, the circumstances under which these turbines operate in Ciudad Juarez are discussed economically. Findings indicate that the study site is not economically appropriate, not even for the installation of specific small wind turbines. Finally, it was suggested that the viability of adopting alternative renewable energy systems, such as solar and hybrid systems (photovoltaic wind), be examined in the upcoming study in Ciudad Juárez.

Highlights The single flash geothermal cycle was subjected to advanced exergy analysis. Endogenous/exogenous and unavoidable/avoidable energy destruction were investigated. The results of the enhanced exergy analysis are distinct and more practical.

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La pandemia por COVID-19 fue difícil para todos y aún más para los hospitales y el personal médico. Los contagios por esta enfermedad fueron muchos en muy poco tiempo debido a esto los hospitales recurrieron a utilizar herramientas de ingeniería para gestión eficaz y eficiente de los pacientes con síntomas graves de COVID-19. Considerando lo anterior es posible aplicar un método de decisión multicriterio para priorizar los objetivos que se requieren cumplir para lograr la mejor atención medica de los pacientes con síntomas graves. Los resultados obtenidos es que el criterio que se debe enfocar primero es la utilización de plataformas digitales para la comunicación como WeChat, WhatsApp, Telegram, debido a que dichas plataformas ofrecen una comunicación instantánea por medio de texto, imágenes, documentos, videos o audios y que no requiere presencia física entre la sala de aislamiento y el exterior, en comparación con los obtenidos en la Universidad de Huazhong, este método definiría el orden de prioridad en que se deben realizar estos objetivos. Finalmente, los resultados obtenidos demuestran que es posible establecer prioridad en la gestión de las cargas de trabajo en la atención de los pacientes con la enfermedad COVID. Palabras claves: MOORA, Escala de Likert, PDCA, COVID-19. Códigos JEL: D14, D61, I31, O33, 035, P18. Recibido: 04/04/2021. Aceptado: 26/07/2021. Publicado: 18/12/2021.

At the end of 2018, a call for papers was made for the Special Issue called “Applied Engineering to Lean Manufacturing Production Systems”, whose objective was to bring together different articles with industrial applications of the different lean manufacturing (LM) tool theories for problem-solving and case studies that improve the indices of the production systems [...]

In industrial production processes, different techniques, tools, philosophies, and methodologies are applied to facilitate their management and control [...]

This study presents a comprehensive approach to evaluate the impact of various Lean Management tools, such as Kaizen, Total Productive Maintenance (TPM), Just-in-Time (JIT), and philosophies like Total Quality Management (TQM)on the social sustainability of manufacturing companies. Using a system dynamics model supported by structural equation analysis, we seek to measure these effects and determine the time required for companies to reach the desired level of implementation of these tools and the point at which they will achieve social sustainability. This innovative approach seeks to fill a gap in the research, as so far, no studies have been conducted that precisely measure the impact of Kaizen, TPM, JIT, and philosophies like TQM on social sustainability using structural equation modeling and system dynamics. This gap in the literature highlights the relevance of this study, which provides detailed results on the impact of Lean Management tools on social sustainability and addresses a significant gap in existing research. Data were collected from 411 surveys, primarily from companies in the automotive sector with more than 1,000 employees. The analysis used tools such as WarpPls 8.0® for structural equation analysis and STELLA ARCHITECT V3.0.1® for system dynamics. The results suggest that continuous improvement is fundamental to achieving social sustainability, serving as an enabler for tools such as TPM and JIT, which are integral to Lean Management, as well as philosophies like TQM. The projection indicates that achieving 100% implementation of these Lean Management tools will take approximately seven years while attaining 100% social sustainability is expected within 10.25 years. It's important to note that while Lean Management tools like TPM and JIT play a crucial role, TQM, as a separate philosophy, also contributes significantly to social sustainability. Although these timelines are ambitious and theoretical, they underscore the critical importance of Lean Management tools for social sustainability. Caution is advised, acknowledging the potential challenges of achieving such ambitious goals, which should be approached with realism. [ABSTRACT FROM AUTHOR]

Several universal genomic traits affect trade-offs in the capacity, cost, and efficiency of the biochemical information processing that underpins metabolism and reproduction. We analyzed the role of these traits in mediating the responses of a planktonic microbial community to nutrient enrichment in an oligotrophic, phosphorus-deficient pond in Cuatro Ciénegas, Mexico. This is one of the first whole-ecosystem experiments to involve replicated metagenomic assessment. Mean bacterial genome size, GC content, total number of tRNA genes, total number of rRNA genes, and codon usage bias in ribosomal protein sequences were all higher in the fertilized treatment, as predicted on the basis of the assumption that oligotrophy favors lower information-processing costs whereas copiotrophy favors higher processing rates. Contrasting changes in trait variances also suggested differences between traits in mediating assembly under copiotrophic versus oligotrophic conditions. Trade-offs in information-processing traits are apparently sufficiently pronounced to play a role in community assembly because the major components of metabolism—information, energy, and nutrient requirements—are fine-tuned to an organism’s growth and trophic strategy.