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Since its launch in January 2021, Ki Culture's Waste and Materials Ki Book has been downloaded over 5,000 times by practitioners of cultural heritage worldwide, establishing the online sustainability manual as one of the leading guides for mitigating the environmental burden of materials we encounter in conserving cultural heritage. The sustainability manual initially focused on finding alternatives to reduce waste and lessen the environmental impact of the plastic materials we encounter in collections care and transport. This led to exploring emerging alternative materials such as bioplastics as potential replacements for petroleum-derived plastics. Terms such as 'biodegradable', 'compostable', 'green', 'environmentally friendly', and 'sustainable' are commonly used in the marketing strategies for bioplastics and biobased materials. However, the question arises: are these alternatives better options for the environment and cultural heritage than their plastic counterparts? Some of the materials highlighted in the Waste and Materials Ki Book showed evidence of greenwashing. What constitutes a sustainable material, and how do we identify and trust the 'green' alternatives available? By honing our criteria for environmentally responsible materials and examining the terminology associated with bioplastics, we can identify greenwashing. This paper critically evaluates so-called green alternatives in conservation, with a focus on greenwashing associated with polylactic acid (PLA). Emphasizing the need for informed decision-making, the study directly reflects the ongoing revision of the Waste and Materials Ki Book. [ABSTRACT FROM AUTHOR]

Copyright of Revista Iberoamericana de Ingeniería Mecánica is the property of Editorial UNED and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The use of polylactic acid (PLA) in the technology of fused deposition modeling (FDM), better known as 3D printing, to create all kinds of parts, from prototypes and simple pieces to highly technical end products, is a significant contender due to its wide range of properties compared to other petrochemical-based composite materials. The aim of this study was to evaluate the use of polylactic acid (PLA) for the construction of unmanned aerial vehicles (UAVs) through 3D printing. Power and force calculations for the UAV were performed, and a structural analysis using SolidWorks software was conducted to calculate maximum and minimum stresses and determine optimal manufacturing parameters. Additionally, an aerodynamic analysis using ANSYS software was carried out to determine the drag coefficient and the forces acting on the UAV. It was found that the force exerted by the motors on the arms is 13,63 N, and the power is 536 N. In the structural analysis, it was determined that the minimum stresses are located in the chassis arms, while the maximum stresses are found where the chassis is attached, with a value of 6,604 MPa and a safety factor of 3,23. In the aerodynamic analysis, a drag force of 1 N and a flight power of 108,44 N were calculated. The UAV achieved a flight height of 48 m and a flight autonomy of 17 minutes, concluding that 3D printing technology is a viable and cost-effective alternative. [ABSTRACT FROM AUTHOR]

La producción de materiales poliméricos a nivel mundial representa un consumo estimado en volumen de 359 millones de toneladas en el último año. Los polímeros, por su versatilidad de producción y aplicación en diversos campos de la industria, hoy en día están generando un problema ambiental por las grandes cantidades de residuos que se generan para su disposición final. Con el objetivo de encontrar aplicaciones amigables con el medio ambiente, se han venido desarrollando diferentes tipos de materiales como son los biopolímeros, que se pueden utilizar para fabricar materiales compuestos de matriz polimérica con algún tipo de carga de origen orgánico como las fibras naturales, para elaborar productos para el sector alimenticio, de construcción y automotriz, entre otros. Los polímeros biodegradables se han convertido en una buena opción para ser empleados como material sustituto que puedan mitigar en cierta proporción el impacto ambiental generado por los polímeros convencionales. El presente trabajo reporta una revisión bibliográfica que muestra la tendencia de aplicación de los biopolímeros de matriz polimérica con fibra natural. Para este propósito, se generó una búsqueda de información relevante sobre las tendencias de estos materiales, como también de sus diferentes aplicaciones en diversos sectores de la industria a nivel mundial, que permitan dar un conocimiento claro de las nuevas tendencias de la investigación para futuros desarrollos e investigaciones.

The conservation of the environment has led to research some polysaccharides with the objective of obtain bioplastics that can be dosed with other polymers and to has better properties. In this research, carried out a thermomechanical study of a dosage between polylactic acid obtained from potato starch with a thermoplastic polymer aliphatic polyester type called adipate socianate polybutylene. They were made different mixtures and analyzes such as differential scanning, thermogravimetric, infrared spectroscopy, fluidity index, hardness "SHORE" and a mechanical thermo-dynamic; and based on the results obtained, was determined the type of processing that the dosage can undergo. The dosages stated was from 94.5% PLA with 5% PBSA to 20% PLA with 79.5% PBSA adding 0.5% crodamide as a lubricating agent. The results concluded that the bioplastic in general can be processed by extrusion and thermoforming, because the values of the melt index are relatively low. [ABSTRACT FROM AUTHOR]

The main objective of this research study was to develop a bilayer active biocomposite (BA) from cassava bran, fique, and glycerol with a coating of polylactic acid (PLA) and nisaplin® that would allow its implementation in high humidity food matrices. Mechanical and thermal properties, water absorption, and antimicrobial effect on Escherichia coli were evaluated. A one-factorial completely randomized experimental design was performed with four concentrations of nisin. The flexural test revealed that the addition of PLA and nisin had no significant effect on stress or flexural modulus. Thermal analysis by differential scanning calorimetry (DSC) resulted in two endothermic peaks, one exothermic peak, and one glass transition peak. The BA's water absorption test had a percentage of 35%. It is concluded that the BA had no inhibitory effect on E. coli, but showed promissory potential for its application in high humidity foods. [ABSTRACT FROM AUTHOR]

El alto índice de contaminación plástica en la actualidad ha llevado a la búsqueda de soluciones que sean amigables con el ambiente. Se presenta un estudio de la fabricación de polímero biodegradable a base de almidón de tubérculos panameños seleccionados (yuca, ñame, otoe y ñampí) y su evaluación mediante un análisis de tensión y biodegradación. Se generó un procedimiento para la extracción de almidón de los tubérculos, así como de la fabricación de biopolímero. El ensayo de tensión se hizo de manera artesanal con una probeta ASTM D638-14 tipo IV incrementando progresivamente el peso y registrando fotográficamente hasta su fractura. El ensayo de biodegradación se monitoreaba la presencia de hongos, se hizo un ensayo con una solución con enzimas digestivas que contenía amilasa, registrando su desintegración en 24 horas y por último, se sembraron los segmentos directamente al suelo y se registró su descomposición después de 7 y 15 días. Se pudo extraer el almidón y fabricar biopolímeros de todos los tubérculos mediante la metodología presentada. La acuosidad del almidón decantado variaba según el tubérculo. El biopolímero generado por ambos fue muy similar y dos de los óptimos para fabricar y cortar. En los ensayos de tensión el biopolímero de otoe mostro mayor resistencia al esfuerzo y deformación previa a la fractura comparado con los demás tubérculos y biopolímero de almidón de maíz utilizando la misma metodología de fabricación. Todos los biopolímeros mostraron avances en su proceso de biodegradación.

The production of polymeric materials worldwide in a wide range of applications represented an estimated consumption volume of 359 million tons last year. Polymers, due to their versatility of production and application in various fields of industry, are currently generating an environmental problem due to the large amounts of waste generated for their final disposal. To find environmentally friendly applications, different types of materials have been developed, such as biopolymers, which can be used to manufacture polymeric matrix composite materials with some type of organic filler such as natural fibers to produce products for the food, construction, and automotive sectors, among others. Biodegradable polymers have become a good option to be used as a substitute material that can mitigate to a certain extent the environmental impact generated by conventional polymers. This bibliographic review shows the application trend of polymeric matrix biopolymers with a natural fiber. For this purpose, a search for relevant information on the trends of these materials, as well as their different applications in various sectors of the industry worldwide, was made to provide a clear understanding of the new trends for future developments and research. [ABSTRACT FROM AUTHOR]

Introduction: since 2017 we have developed a 3D printing program in the Orthopedic Surgery and Traumatology Unit of the Central Hospital of Defense «Gómez Ulla». The objective of this work is to present the preliminary results obtained and the difficulties encountered in the use of 3D printing technology applied to military surgery. Material and methods: impressions of surgical instruments usually used in orthopedic surgery were made, recording the model of the printer used, the time required for printing it, the material used, as well as the quality of the product obtained. Subsequently, the instruments were tested and their resistance was recorded. Results: twenty-seven surgical instrument devices were created by additive manufacture using Polylactic Acid (PLA) and Acrylonitrile Butadiene Styrene (ABS) with two 3D printer models. The unit price of the devices printed in PLA did not exceed 2 euros, while that of those printed in ABS was 3 euros. Average print times were similar on both 3D printer models. Failures were recorded in four devices printed in PLA, while the models printed in ABS did not present failures and obtained better scores in the aspects surveyed. Conclusions: using 3D printing, models of surgical instruments similar to those we use in surgical steel were obtained. The production of these models is relatively fast, being these more resistant and reliable when using ABS as a printing material. More studies are necessary in this research line to define the limits of 3D printing applied to military surgery. [ABSTRACT FROM AUTHOR]

Hoy, los avances tecnológicos han llevado al descubrimiento de métodos de fabricación desarrollados recientemente. La tecnología de fabricación aditiva con impresora tridimensional (3D) es uno de estos nuevos métodos. En este método, se pueden fabricar piezas con geometría compleja que no se pueden producir mediante métodos convencionales. El método más popular y de bajo precio entre las tecnologías de fabricación aditiva es FDM (Fused Deposition Modeling). En este estudio, se ha realizado el diseño y la fabricación de impresoras 3D utilizando tecnología FDM. Se han determinado cinco geometrías de relleno diferentes, como reloj de arena (HG), giroide (GY), octaédrico (OC), triángulo (TR) y cuadrícula (GR), luego se aplicaron las pruebas de tracción y flexión de 3 puntos a las muestras fabricadas de polímero de ácido poliláctico (PLA) y las propiedades mecánicas se compararon entre sí. El aspecto más importante del estudio es la comparación de la geometría del relleno de la rejilla, que se ha estudiado ampliamente en la literatura, y las geometrías raramente estudiadas como el reloj de arena, el giroide, el octaédrico y el triángulo en términos de propiedades mecánicas. Se concluyó que el tipo de sección transversal diferente tiene un efecto significativo, especialmente en la resistencia a la tracción. Los valores de resistencia más altos se determinaron en las muestras con geometría de relleno triangular.

The quality of some polymers to change their final physical and chemical properties by adding nanoparticles to the polymer matrix to produce a composite material (MC) is well known. This research is based on obtaining a MC from polylactic acid (PLA) and multi-walled carbon nanotubes (CNTMW), widely used in the packaging industry and biomedical devices, in order to expand its industrial profile. Four mixtures of PLA and CNTMW were developed, and polyethylene glycol (PEG) was used as a plasticizer. Their morphological, thermal, mechanical, thermo-mechanical, spectroscopic, contact angle, and crystallographic properties were evaluated. It was observed that the composites showed thermal degradation at temperatures below the matrix without CNTMW, as well as an increase in the modulus of flexion and tension in some of the samples. Likewise, it was observed that the CNTMW can increase the crystallinity of the material and that, in some cases, its rigidity is increased, acting as a useful additive for applications of greater mechanical stress than the matrix. From the effect of adding PEG in the composites, the CNTMW do not restrict the mobility of the polymer chains and a plasticizing effect occurs, which allows greater mobility of the amorphous zone of the polymer chains. In general terms, it was concluded that at higher CNTMW contents, better values were generated in the flexural modulus, maximum flexural stress, elongation modulus, maximum load stress and rupture stress, among other evaluated properties. [ABSTRACT FROM AUTHOR]

Las guías quirúrgicas son dispositivos biomédicos indispensables para la inserción adecuada de los implantes dentales; actualmente se dispone de 2 tipos de guías: las “restrictivas” y las “no restrictivas”, siendo las primeras las que brindan un mayor grado de estabilidad y exactitud, pero a un costo muy elevado. En este trabajo se propone la elaboración de un nuevo tipo de guía que combina una determinación protésica y la incorporación de información tomográfica con técnicas de impresión 3D para obtener un dispositivo con buen ajuste y adecuada exactitud, pero a un menor precio. El producto obtenido fue elaborado en ácido poliláctico y mostró unas buenas propiedades de adaptación, rigidez y estabilidad lo que puede garantizar un buen desempeño clínico. Si bien las guías convencionales son muy económicas presentan problemas de estabilidad que comprometen la seguridad del procedimiento quirúrgico y por lo tanto la salud del paciente; con la técnica propuesta se puede obtener una guía quirúrgica precisa, estable y a un precio razonable conservando los principios de la predeterminación protésica y asegurando que los procedimientos quirúrgicos sean adecuados y seguros. La elaboración del dispositivo mediante impresión 3D a partir de una predominación protésica es técnicamente viable, sin mayores complejidades técnicas y podría ser una alternativa real a las guías restrictivas las cuales aún son demasiado complejas y costosas.

En esta investigación, nanofibras de celulosa (CNF) de Chusquea quila fueron usadas como refuerzo del ácido poliláctico (PLA) en la fabricación de membranas en electrospinning. El objetivo de este trabajo fue analizar la incidencia de las CNF en las propiedades mecánicas del PLA. Para demostrar lo anterior, fueron elaboradas membranas sin adición de CNF y membranas con CNF en porcentajes de 1%, 3% y 5% con respecto al peso del PLA. Las CNF y las membranas fueron caracterizadas morfológicamente. Además, las CNF fueron acetiladas para lograr dispersión en el PLA. Asimismo, las membranas fueron sometidas a ensayos de tracción y resistencia al desgarro. Se encontró que la adición del 1% de CNF refuerza el material ante esfuerzos de tracción y desgarro. [ABSTRACT FROM AUTHOR]

Surgical guides are essential biomedical devices for the proper insertion of dental implants; there are two types of guides, a "restrictive" and "non-restrictive" these are currently available in the dental field, the first one provides a great degree of stability and accuracy, but at a very high cost. This paper proposes the development of a new type of guide that combines a prosthetic determination and the incorporation of tomographic information with 3D printing techniques to obtain a device with good fit and adequate accuracy but at a lower price. The product obtained was elaborated in polylactic acid and showed good adapting properties, rigidity and stability which would guarantee a good clinical performance. Even though conventional guides are very economical, they present a lot of stability problems that compromises the security of the surgical procedure and therefore patient's health; with the proposed technique an accurate, stable and reasonably price surgical guide can be obtained keeping the principles of prosthetic predetermination and ensuring that surgical procedures are adequate and safe. The manufacturing of devices through 3D printing from a from predominance of the prosthesis is technically viable, without major technical complexities and could be a real alternative to restrictive guides which are still too complex and expensive. [ABSTRACT FROM AUTHOR]

Os autores avaliam clinicamente 19 pacientes (19 joelhos - 15 meniscos mediais e 5 laterais) submetidos à sutura de menisco, utilizando 2 tipos de implantes absorvíveis (ácido polilático) Arrow® e Clear fix®. O estudo compõe-se de 15 homens e 4 mulheres com idades entre 16 e 44 anos, com média de 26,8 anos. O tempo de seguimento médio foi de 24 meses, com mínimo de 18 e máximo de 32 meses. A técnica operatória constituiu-se da sutura de um ou ambos os meniscos (1 caso), via artroscópica com Arrow® em 15 pacientes e Clear fix® em 4. Dos 19 indivíduos, 6 foram submetidos à sutura meniscal isolada, 11 associada à reconstrução do LCA e 2 à reconstrução do LCA com osteotomia valgizante da tíbia. Os resultados foram avaliados segundo exame físico incluindo as manobras de Appley e Mc Murray. A avaliação funcional pré e pós-operatória do joelho foi realizada pela escala de Lysholm modificada. Todos os pacientes tiveram suas manobras meniscais negativadas no pós-operatório. A pontuação média pré-operatória segundo a escala de Lysholm foi de 39,8 subindo para 91,5 no pós-operatório. Os autores concluem que a sutura de menisco, utilizando implantes absorvíveis, tem se mostrado eficiente até o momento, e que tecnicamente ela é mais simples que a sutura convencional.The authors clinically assessed 19 patients (19 knees - 15 medial meniscus and 5 lateral meniscus) submitted to meniscus suture using 2 kinds of absorbable implants (polylactic acid) Arrow® and Clear fix®. The study is composed of 15 males and 4 females, ages ranging 16 - 44 years old (average = 26.8 years old). The mean follow-up time was 24 months, ranging from 18 to 32 months, at most. The surgical technique was constituted of a suture in one or both meniscus (1 case), through arthroscopy with Arrow® in 15 patients and Clear fix® in 4. From the 19 individuals, 6 were submitted to isolated meniscal suture, 11 combined to ACL reconstruction and 2 to ACL reconstruction with tibial valgusing osteotomy. The results were assessed according to physical examinations including the maneuvers of Appley and Mc Murray. Pre- and postoperative functional evaluation of the knee was performed using a modified Lysholm scale. All patients had negative meniscal maneuvers postoperatively. The average preoperative score according to Lysholm scale was 39.8 reaching 91.5 postoperatively. The authors conclude that the meniscus suture using absorbable implants has shown to be efficient so far, and that, technically, it is simpler than conventional suture.

Copyright of DYNA - Ingeniería e Industria is the property of Publicaciones Dyna SL and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Superficies y Vacío is the property of Sociedad Mexicana de Ciencia y Tecnologia de Superficies y Materiales and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The polilactic acid (PLA), is a thermoplastic biopolymer which precursor molecule is the lactic acid. Due to its biodegradability, barrier properties and biocompatibility; this biopolymer had found industrial and medicals applications since it presents a wide range of unusual properties, from the amorphous to the crystalline state. These properties could be manipulate with blends between D(-) and L(+) isomers, molecular weight and copolymerization. This article is a review of polilactic acid its polymerizations forms, physicals and mechanicals interesting properties, biodegradability and reabsorption mechanisms and applications in different fields. Besides, it tried about the biotechnological production process of its precursor molecule, emphasizing the research in news substrates, new producers microorganism and different methods of purification. [ABSTRACT FROM AUTHOR]