Research on Dynamic Response of Slopes With Weak Interlayers Under Mining Blasting Vibration

As blasting technology starts to be used in a wide range of areas, blast loading has led to an increasing number of geological disasters such as slope deformation, collapses, and soil slippage. Slopes with weak interlayers are more likely to be deformed and damaged under the influence of blast loading. It is of great importance to study the evolution for the deformation of slopes with weak interlayers during blasting excavation. This study constructed a slope model with a weak interlayer to investigate the influence of different factors of blasting, including explosive charge, blast radius, blast origin, and multi-hole blasting, on the internal dynamic response. The deformation mechanism of slopes with weak interlayers under the influence of blast loading was analyzed. Test results show that each layer of the model had a different displacement response (uncoordinated dynamic response) to blasting with various factors. Explosive energy and the pattern of dynamic response of each layer varied depending on different settings of blasting factors such as explosive charge, blast radius, blast origin, and detonation initiation method. When the explosive energy produced under the influence of various factors was small, the change in the uncoordinated dynamic response between layers was significant, and the change gradually became less significant as the explosive energy increased. Therefore, this study has proposed the concept of critical explosive energy, and it is speculated that when the explosive energy produced with various factors is less than critical explosive energy, the dynamic response is mainly affected by the internal structure of the slope (property difference induced geologic layers). In other words, the uncoordinated motion of material’s particles in each layer is caused by different limitations and the degree of movement of the particles, which leads to the uncoordinated dynamic response and uncoordinated deformation of each layer. If the explosive energy is greater than the critical value, the dynamic response of each layer is mainly affected by the explosive energy. The differences in the internal structure of the slope are negligible, and the incoordination of dynamic responses between layers gradually weakens and tends to synchronize.

A New Story on the Multidimensionality of the MSPSS: Validity of the Internal Structure through Bifactor ESEM

The internal structure of the Multidimensional Scale of Perceived Social Support (MSPSS) in adolescents has been evaluated with some factorial analysis methodologies but not with bifactor exploratory structural equation modeling (ESEM), and possibly the inconsistency in the internal structure was dependent on these approaches. The objective of the study was to update evidence regarding its internal structure of MSPSS, by means of a detailed examination of its multidimensionality The participants were 460 adolescents from an educational institution in the Callao region, Lima, Peru. The structure was modeled using unidimensional, three-factor and bifactor models with confirmatory factor analysis (CFA) and ESEM approaches. The models showed good levels of fit, with the exception of the unidimensional model; however, the multidimensionality indicators supported the superiority of the bifactor ESEM. In contrast, the general factor was not strong enough, and the interfactorial correlations were substantially lower. It is concluded that the MSPSS can be interpreted by independent but moderately correlated factors, and there is possible systematic variance that potentially prevented the identification of a general factor.

Model of Filling the Internal Structure of Workpiece with Curved Layers for 3D Printing

This paper presents a solution to the problem of filling the internal structure of the workpiece with curve layer in 3D printing. A generalized model of filling the internal structure of workpiece with curve layer is designed. The results are presented for solving the problem on the example of curved layers of a conical shape with filling along a helical line. The research results can be in demand in the development of algorithms and software for technological equipment. They allow to ensure the formation of the internal structure of products in curved layers during 3D printing.

Psychometric properties of the positive mental health scale in Arequipa (Peru)

La salud mental positiva es un constructo complejo que está relacionado con el funcionamiento óptimo de la persona. Comprende un conjunto de cualidades orientadas al desarrollo del potencial del individuo. La Escala de Salud Mental Positiva es uno de los instrumentos más utilizados para evaluarlo, sin embargo, los antecedentes señalan inconsistencias respecto a su estructura interna. El objetivo del presente estudio fue analizar las propiedades psicométricas de la Escala de Salud Mental Positiva en Arequipa-Perú. Participaron 3933 personas, 50.3% fueron mujeres y 49.7% fueron varones, incluyendo desde adolescentes hasta adultos mayores. La evaluación mediante AFC de la estructura original evidenció índices de ajuste pobres, por lo que se tuvo que evaluar la dimensionalidad y proponer una nueva estructura. Para lo cual, se dividió a la muestra (n1 = 1966 y n2 = 1967). En la primera, se aplicó un AFE y en la segunda se valida mediante un AFC. Se hallaron tres factores y se concluye que tiene un buen ajuste (χ2(431) = 2473.378; CFI = .959; TLI = .956, RMSEA = .049; SRMR = .051). La consistencia interna mostró valores mayores a .81. Finalmente, se evaluó la equivalencia de la medición según el sexo, hallando que el instrumento presenta invarianza de la medición. Positive mental health is a complex construct that is related to the optimal functioning of the person. It comprises a set of qualities aimed at the development of the individual's potential. The Positive Mental Health Scale is one of the most used instruments to evaluate it, however, the antecedents indicate inconsistencies regarding its internal structure. The objective of this study was to analyze the psychometric properties of the Positive Mental Health Scale in Arequipa-Peru. 3,933 people participated, 50.3% were women and 49.7% were men, including from adolescents to the elderly. The evaluation by CFA of the original structure showed poor fit indices, so the dimensionality had to be evaluated and a new structure had to be proposed. For which the sample is divided (n1 = 1,966 and n2 = 1,967). In the first, an EFA was applied and in the second, it is validated by means of a CFA. Three factors were found and it is concluded that it has a good fit (χ2 (431) = 2,473.378; CFI = .959; TLI = .956, RMSEA = .049; SRMR = .051). The internal consistency showed values ​​greater than .81. Finally, the equivalence of the measurement according to sex was evaluated, finding that the instrument presents measurement invariance.