Center for Engineering and Industrial Development

The Santa Catarina Dam (Querétaro, Mexico) is a freshwater reservoir supporting agriculture and aquaculture, but anthropogenic pressure has intensified nutrient enrichment and contamination. Water samples were collected from two points for physicochemical characterization and shotgun metagenomic profiling. DNA sequences were quality filtered, assembled, and classified to quantify taxonomic composition and functional gene abundance. Processed data were statistically analyzed in Python 3.0 to compare physicochemical parameters, taxa, and gene abundance. Results showed that chemical oxygen demand (COD) and hydrogen potential (pH) exceeded recommended limits. Fecal coliform counts (FCC) were high at both points, while biochemical oxygen demand (BOD5) and total nitrogen (TN) approached critical thresholds. Significant differences in water temperature (WT), dissolved oxygen (DO), and total phosphorus (TP) were observed between sites. The microbial communities presented high diversity and a moderate dissimilarity among points. Besides, three cyanobacterial species were identified within the top 10 most abundant taxa. Functional annotation of the combined dataset revealed high gene abundance associated with energy production (35.40%), stress resistance (18.00%), and unknown functions (14.54%). These results indicate an eutrophic state of the water body and potential health risks. Differential statistical analysis revealed site-specific taxa and genes, several of which may have biotechnological applications.

The rapid evolution of innovative materials and their 4D printing on fabrics allows textiles to change shape or properties when exposed to external stimuli. This work reviews the fundamentals of 4D printing, briefly revisiting additive manufacturing technology and materials, as both are extensively described in various articles and reviews. It also outlines the advancements in smart textiles and their functionality as multifunctional fabrics. The review focuses primarily on reviewing the technical foundations and emerging applications of 4D-printed smart polymers and their integration onto passive textiles for smart applications. Finally, a critical review is presented, emphasizing the numerous individual developments undertaken not only in academia but also by young students, independent engineers, and entrepreneurs who showcase their progress and various challenges through social media. Easy access to knowledge, digital communication, and an interest in creating new materials and structures with a relatively low budget will allow the advancement and development of 4D printing processing strategies for functional materials, promoting the creation of intelligent and adaptive textile systems.

The majority of maize-based foods are produced via nixtamalization, which includes toasted tortillas (tostadas). Women artisanal producers in Chiapas, Mexico, have refined key quality parameters, such as texture and resistant starch content, by using native maize varieties that preserve traditional traits. Nixtamalization modifies maize functionality through the formation of resistant starch, which resists digestion and supports beneficial colonic microbiota via short-chain fatty acid production. This study aimed to evaluate the functional, sensory, and structural properties of tostadas that were prepared via two cooking processes using native maize from Chiapas. In this research, starch gelatinization was achieved through three different processes: traditional nixtamalization (control), short boiling, and full boiling. The resulting tostadas were: nixtamalized corn tostadas (NCT), partially-burst tostadas (PBT), and fully-burst tostadas (FBT), respectively. Tostada sensory attributes were analyzed by a trained panel that assessed multiple parameters, namely crunchiness, fracturability, hardness, corn aroma, nixtamal aroma, corn taste, nixtamal taste, and stickiness. On the other hand, consumer testing was used to evaluate chewing parameters. Partially-burst tostada (PBT) and fully-burst tostada (FBT) exhibited structural, functional, and sensory properties that are associated with the sensation of satiety and liking. Corn races did not have a statistically significant effect on the rheological or sensory properties of tostadas. However, the nixtamalization method significantly influenced stickiness and taste parameters. Stickiness intensity (4.50) and eating rate (62.66 g/min) for FBT were statistically different from PBT’s respective values (3.75 and 56.12 g/min). These characteristics favor the chewing process. When maize is cooked for longer periods, the peak of amylose–lipid complexes is more easily detected. Resistant starch in FBT was higher (5.6%) than in PBT and NCT, which were 3.7% and 2.4%, respectively. Key tostada quality parameters, such as chewiness and sensory characteristics, correlated well with the structural and rheological properties of the modified starch (partial gelatinization) formed during tostada preparation.

Porosity characterization in metallic alloys is a fundamental aspect of materials engineering due to its influence on mechanical and structural properties. This study presents a method based on digital image processing for detecting and analyzing porosity in the AlSi10Mg aluminum alloy, additively manufactured using laser powder bed fusion (L-PBF). X-ray computed tomography, segmentation algorithms and filtering techniques were employed to identify and quantify the porosity present in the material’s microstructure. The research demonstrates that combining numerical methods with qualitative analysis provides a comprehensive understanding of porosity characteristics. Notably, the effectiveness of the proposed image processing methods was validated by comparing the results with actual material density measurements. However, challenges such as the need for proper calibration and potential imaging artifacts affecting accuracy were identified. This study represents a significant advancement in materials engineering, offering a detailed methodology for porosity analysis in aluminum alloys that not only enhances quality control and process optimization, but also improves segmentation accuracy and facilitates the reliable detection of small and interconnected pores in complex additively manufactured geometries.

Perfect crystals can be obtained, hypothetically, only at absolute zero. Though the nanomaterials are so small, they are more prone to defects than their bulk counterparts. Irregularities in the crystal arrangement and periodicity are related to defects, which, in turn, have certain energy associated with them. Thus, defects are considered as active sites. For that reason, the structural features of lattice defects can significantly influence the properties of nanomaterials, highlighting their advantages. The study of such imperfections is crucial to understand the performance of nanomaterials. Hence, the comprehension of such imperfections can allow innovations in several fields of science and technology. In this chapter, the surface defects are analyzed and discussed in the context of their impact over the properties related to energy production and storage in nanomaterials. Furthermore, in this chapter, the surface defect typology as well as their formation are also addressed.

Thermoacoustic refrigerators offer a promising alternative to conventional refrigeration technologies because their unique operating principles pose no harm to the environment. This study focuses on key performance indicators (KPIs) for thermoacoustic refrigerators, relative to their performance efficiency. The coefficient of performance (COP), the Carnot coefficient of performance (COPC) and the coefficient of performance relative to Carnot’s COP (COPR), crucial KPIs, are analyzed within the framework of Carnot efficiency (temperature difference). By comparing the analyzed performance metrics of a thermoacoustic refrigerator, such as COP and COPR, for a case study, the analysis provides insights into areas for improvement and optimization. The results highlight the potential and limitations of the temperature difference in current thermoacoustic technologies and suggest pathways for enhancing their efficiency to meet or exceed traditional refrigeration benchmarks.