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Advances in high-pressure grinding roll (HGPR) technology since its first commercial application in the cement industry include new roll wear protection techniques and new confinement systems. The latter contribute to reductions in the edge effects in an attempt to reach a more homogenous product size along the rolls. Additional advances in this technology have been made in recent years, while modeling and simulation tools are also reaching maturity and can now be used to subject such novel developments to detailed scrutiny. This work applies a hybrid approach combining advanced simulations using the discrete element method, the particle replacement model and multibody dynamics to a phenomenological population balance model to critically assess two recent advances in HPGR technology: spring-loaded cheek plates and the offset roller press. Force and torque controllers, included in the EDEM 2022.1 software, were used to describe the responses of the geometries in contact with the granular material processed. Simulations showed that while the former successfully reduced the lateral bypass of the material by as much as 65% when cheek plates became severely worn, the latter demonstrated lower throughput and higher potential wear but an ability to generate a finer product than the traditional design.

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Considering the continuous increase in production costs and resource optimization, more than a strategic objective has become imperative in the copper mining industry. In the search to improve the efficiency in the use of resources, the present work develops models of a semi-autogenous grinding (SAG) mill using statistical analysis and machine learning (ML) techniques (regression, decision trees, and artificial neural networks). The hypotheses studied aim to improve the process's productive indicators, such as production and energy consumption. The simulation of the digital model captures an increase in production of 4.42% as a function of mineral fragmentation, while there is potential to increase production by decreasing the mill rotational speed, which has a decrease in energy consumption of 7.62% for all linear age configurations. Considering the performance of machine learning in the adjustment of complex models such as SAG grinding, the application of these tools in the mineral processing industry has the potential to increase the efficiency of these processes, either by improving production indicators or by saving energy consumption. Finally, the incorporation of these techniques in the aggregate management of processes such as the Mine to Mill paradigm, or the development of models that consider the uncertainty of the explanatory variables, could further increase the performance of productive indicators at the industrial scale.

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Based on 74 ore-processing plants and their energy meter's coordinates in Zaruma-Portovelo, we determined the energy consumption profiles for each ore-processing plant following the methodologies of Gonçalves (2016) and Cabezas (2016). In doing so, the total energy consumption in comminution processes was calculated. Data show a rising trend in energy consumption in ore processing in Zaruma-Portovelo. The data can be of immense use in designing sectoral reforms for transparency in the mining sector and developing cross-sectoral coordination between ARCOM and ARCONEL. The data can also help the state agencies in assessing the quantity of ore processed and preventing the leakage of revenue from the extractive sectors (Gaudry et al., 2020). Finally, the scientific community may benefit from this data, particularly those working on energy consumption, efficiency, and its forecasts in extractive sectors (Gaudry et al., 2020).

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Abstract The use of two-implant overdentures improves mastication of edentulous elderly patients. However, little is known about the effects of single-implant overdentures (SIO) on oral perception and masticatory function in such elders. This study compared the effects of conventional complete dentures (CD) and SIO on the oral sensorimotor ability (OSA), masticatory function, and nutritional intake of elderly people with residual alveolar mandibular height classified as Class III or IV according to the American College of Prosthodontics. Twelve elders first received new conventional CD, which were later converted to SIO. All variables were evaluated after use of each prosthesis for 2 months. To evaluate OSA, elders closed their eyes and orally identified test pieces prepared from raw carrots. A kinesiographic device was used to measure chewing movements during mastication of a test material (Optocal). Masticatory performance (MP) was determined with the sieving method, and a 3-day food diary verified nutrient intake based on a standard Brazilian Food Composition Table. Data were analyzed using the Wilcoxon signed rank test and Student's paired t test (P < 0.05). OSA results did not differ according to prosthesis type. However, opening and closing velocities during chewing and MP increased after SIO insertion (P < 0.05). Although no difference was observed in the intake of most nutrients, sodium ingestion decreased after SIO insertion (P < 0.05). SIO use had no effect on OSA, but significantly improved mastication and sodium intake of elders with decreased residual ridges height (Brazilian Registry of Clinical Trials #RBR-3kgttj).

Resumo A utilização de overdentures suportadas por dois implantes melhora a mastigação de pacientes idosos edêntulos que apresentam rebordos residuais reabsorvidos. No entanto, pouco se sabe sobre os efeitos de overdentures suportadas por único implante central mandibular (SIO) em relação à percepção oral e função mastigatória em tais idosos. O atual estudo comparou os efeitos de próteses totais convencionais (CD) e SIO na capacidade de sensorimotora oral (OSA), função mastigatória e ingestão nutricional de idosos com altura de rebordos mandibulares tipo III e IV de acordo com a Colégio Americano de Prótese. Doze idosos receberam primeiramente novas CD convencionais, as quais, posteriormente, foram transformadas em SIO. Variáveis foram avaliadas após o uso de cada prótese durante 2 meses. Para avaliar OSA, os idosos fecharam os olhos e testaram oralmente a identificação de formatos geométricos confeccionados de cenouras cruas. Um dispositivo cinesiográfico foi utilizado para medir os movimentos durante a mastigação de material de teste (Optocal). A performance mastigatória (MP) foi determinada com o método de fracionamento de peneiras e um diário de alimentação aplicado por 3 dias consecutivos verificou a ingestão de nutrientes com base em uma Tabela Brasileira Padrão de Composição de Alimentos. Os dados foram analisados utilizando os testes Wilcoxon signed rank test e Student's paired t test (p<0,05). OSA resultados não diferiram de acordo com o tipo de prótese. No entanto, as velocidades de abertura e fechamento durante a mastigação e MP aumentaram após a inserção de SIO (p<0,05). Embora não tenha sido observada diferença na ingestão da maioria dos nutrientes, a ingestão de sódio diminuiu após a inserção de SIO (p<0,05). O uso de SIO não teve efeito sobre OSA, mas melhorou significativamente a mastigação e a ingestão de sódio de idosos com altura de rebordos residuais reduzidas (Registro Brasileiro de Ensaios Clínicos # RBR-3kgttj).

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RESUMEN: El trauma maxilofacial por arma de fuego representa un desafío terapéutico principalmente debido a la gran conminución de tejidos que genera. Específicamente, en casos de fracturas mandibulares conminutadas, las modalidades de tratamientos incluye la reducción cerrada, fijación con tutor externo, fijación interna con alambres y reducción abierta y fijación interna utilizando placas y tornillos. El objetivo del presente trabajo es describir un tratamiento inicial con un método de fijación para fracturas mandibulares conminutadas como dispositivo alternativo al tutor externo clásicamente utilizado. Se desarrolla una revisión de la literatura actual acerca del tratamiento inicial o de urgencia de fracturas mandibulares conminutadas por impacto de proyectil balístico, haciendo énfasis en las indicaciones de cada modalidad de tratamiento y sus respectivas ventajas y desventajas. Luego se describe detalladamente el proceso de confección de un método de fijación alternativo junto con la exposición de casos clínicos donde fue utilizado como alternativa de tratamiento. La reducción y fijación obtenida por el dispositivo presentado logra resultados satisfactorios, sin encontrarse diferencias significativas a los elementos de fijación clásicos. Tanto el uso de placas de reconstrucción como el de tutor externo constituyen alternativas válidas para el tratamiento de fracturas mandibulares conminutadas. El dispositivo descrito y utilizado en los pacientes es una alternativa eficiente, de fácil confección y bajo costo económico demostrando buenos resultados en relación a la consolidación de fracturas conminutadas. Se debe conocer las indicaciones para la aplicación de cada modalidad de tratamiento.

ABSTRACT: Ballistic maxillofacial trauma represents a challenge for surgeons because of the important comminution process it presents. Specifically, in cases of mandibular comminuted fractures, the different treatment modalities include closed reduction, external fixation and internal fixation. The purpose of this case series is to describe an initial treatment modality, with a fixation method for comminuted mandibular fractures as an alternative for the classic external fixator. We conducted a literature review about the initial treatment for ballistic comminuted mandibular fractures, emphasizing indications of each treatment modality and their respective advantages and disadvantages. Next, we described the preparation process of an alternative fixation method along with a case series, where it was used as a therapeutical alternative. The reduction as well the fixation achieved by the external fixator, showed satisfactory results without significant differences noted with traditional fixation methods. Both, reconstruction plates and external fixators, are valid alternatives for treating comminuted mandibular fractures. The method described and used in these patients is and efficient alternative, easy to make and at a low cost, with good results in relation to fracture consolidation. We propose that every treatment modality and its indications should be evaluated in order to treat each case adequately.

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Due to the environmental impact of construction and demolition waste (CDW), recycling is mandatory. It is also important that recycled concrete aggregates (RCA) are used in concrete to meet market demands. In the literature, the influence of RCAs on concrete has been investigated, but very limited studies have been conducted on how the origin of concrete waste and comminution processes influence RCA characteristics. This paper aims to investigate the influence of three different comminution and sizing processes (simple screening, crushing and grinding) on the composition, shape and porosity characteristics of RCA obtained from concrete block waste. Crushing and grinding implies a reduction of RCA porosity. However, due to the presence of coarse quartz rounded river pebbles in the original concrete block mixtures, the shape characteristics deteriorated. A large amount of powder (<0.15 mm) without detectable anhydrous cement was also generated.

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OBJECTIVE: The acetabular buttress-plate has been widely used in treating difficult cases with satisfying clinical results. However, the biomechanical properties of a postoperative acetabular fracture fixed by the buttress-plate are not clear. The purpose of this study was to evaluate the biomechanical properties of stability after the anterior tube buttress-plate fixation of complex acetabular fractures in the quadrilateral area. METHODS: A construct was proposed based on anterior construct plate - 1/3 tube buttress plate fixation for acetabular both-column fractures. Two groups of six formalin-preserved cadaveric pelvises were analyzed: (1) group A, the normal pelvis and (2) group B, anterior construct plate-1/3 tube buttress plate with quadrilateral area fixation. The displacements were measured, and cyclical loads were applied in both standing and sitting simulations. RESULTS: As the load was added, the displacements were A<B, increasing in line. In the 600 N physiological loading, the differences were significant (standing position: p = 0.013; sitting position: p = 0.009) between groups A and B. CONCLUSION: The anterior construct plate - 1/3 tube buttress plate fixation provided a better stable construct for early sitting. The standing mode yielded more significant differences between the groups. Placing a 1/3 tube buttress-plate via an anterior approach is a novel method of providing quadrilateral area support in this setting. .

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