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1
artículo
Publicado 2024
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The valorization and use of lignocellulosic biomass from food processing to obtain value-added products is crucial to improve sustainability and reduce waste management costs. This potential for cost reduction is a reason for optimism, as it allows agro-industrial waste to be transformed into valuable resources, contributing to the circular economy. This study focused on the compositional and structural characterization of eleven types of lignocellulosic biomass (LCB) to evaluate their potential in producing nanopolysaccharides and polyhydroxyalkanoates. Parameters such as humidity, ash, proteins, extractives, structural carbohydrates, and lignin were analyzed in passion fruit peels, artichoke bracts, asparagus peels, lemon peels, orange peels, avocado seed, potato peels, cassava peels, sugar cane bagasse, rice husk, and rice straw. The results showed that fruit peels and other waste had...
2
artículo
Publicado 2019
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The mechanical behavior of advanced composites can be modeled mathematically through unknown variables and Shear Strain Thickness Functions (SSTFs). Such SSTFs can be of polynomial or non-polynomial nature and some parameters of non-polynomial SSTFs can be optimized to get optimal results. In this paper, these parameters are called “r” and “s” and they are the argument of the trigonometric SSTFs introduced within the Carrera Unified Formulation (CUF). The Equivalent Single Layer (ESL) governing equations are obtained by employing the Principle of Virtual Displacement (PVD) and are solved using Navier method solution. Furthermore, trigonometric expansion with Murakami theory was implemented in order to reproduce the Zig-Zag effects which are important for multilayer structures. Several combinations of optimization parameters are evaluated and selected by different criteria of aver...
3
artículo
Publicado 2016
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This paper presents a static analysis of functionally graded single and sandwich beams by using an efficient 7DOFs quasi-3D hybrid type theory. The governing equations are derived by employing the principle of virtual works in a weak form and solved by means of the Finite Element Method (FEM). A C1 cubic Hermite interpolation is used for the vertical deflection variables while C0 linear interpolation is employed for the other kinematics variables. Convergence rates are studied in order to validate the finite element technique. Numerical results of the present formulation are compared with analytical and FEM solutions available in the literature.
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5
artículo
Publicado 2020
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In this paper, a three-dimensional numerical solution for the bending study of laminated composite doubly-curved shells is presented. The partial differential equations are solved analytically by the Navier summation for the midsurface variables; this method is only valid for shells with constant curvature where boundary conditions are considered simply supported. The partial differential equations present different coefficients, which depend on the thickness coordinates. A semi-analytical solution and the so-called Differential Quadrature Method are used to calculate an approximated derivative of a certain function by a weighted summation of the function evaluated in a certain grin domain. Each layer is discretized by a grid point distribution such as: Chebyshev-Gauss-Lobatto, Legendre, Ding and Uniform. As part of the formulation, the inter-laminar continuity conditions of displacement...
6
artículo
Publicado 2015
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This paper presents an analytical solution for the thermoelastic bending analysis of advanced composite sandwich plates by using a new quasi-3D hybrid type HSDT with 6 unknowns which is based on a generalized formulation. In addition, the nonlinear term of the temperature field is included in the generalized mathematical formulation in such way that it can be freely chosen and if desired can be different from the shear strain shape functions of the displacement field. So, infinite quasi-3D hybrid type HSDTs with just 6 unknowns can be derived from the present generalized formulation. The thermoelastic bending governing equations are obtained through the principle of virtual works and solved via Navier Method. Interesting results are obtained and compared with quasi-3D and 2D HSDTs. Transverse shear stress results are strongly influenced by nonlinear temperature field and for different HS...
7
artículo
Publicado 2020
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El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado.
8
artículo
Publicado 2019
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The mechanical behavior of advanced composites can be modeled mathematically through unknown variables and Shear Strain Thickness Functions (SSTFs). Such SSTFs can be of polynomial or non-polynomial nature and some parameters of non-polynomial SSTFs can be optimized to get optimal results. In this paper, these parameters are called “r” and “s” and they are the argument of the trigonometric SSTFs introduced within the Carrera Unified Formulation (CUF). The Equivalent Single Layer (ESL) governing equations are obtained by employing the Principle of Virtual Displacement (PVD) and are solved using Navier method solution. Furthermore, trigonometric expansion with Murakami theory was implemented in order to reproduce the Zig-Zag effects which are important for multilayer structures. Several combinations of optimization parameters are evaluated and selected by different criteria of aver...
9
artículo
Publicado 2022
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This paper deals with stability of solution for a one-dimensional model of Rao–Nakra sandwich beam with Kelvin–Voigt damping and time delay given by 1ℎ1 − 1ℎ1 − (− + + ) − − ( ・ , − ) = 0, 3ℎ3 − 3ℎ3 + (− + + ) − = 0, ℎ + − (− + + ) − = 0. A sandwich beam is an engineering model that consists of three layers: two stiff outer layers, bottom and top faces, and a more compliant inner layer called “core layer”. Rao–Nakra system consists of three layers and the assumption is that there is no slip at the interface between contacts. The top and bottom layers are wave equations for the longitudinal displacements under Euler–Bernoulli beam assumptions. The core layer is one equation that describes the transverse displacement under Timoshenko beam assumptions. By using the semigroup theory, the well-posedness is given by applying the Lumer–Phillips ...
10
tesis de maestría
Publicado 2025
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Artículo sustentado el 02 de diciembre 2025 para la obtención del grado académico de Maestro en Ciencias de la Ingeniería.
11
artículo
Tooth wear is the loss of hard tissue of multiple aetiology and may be due to functional or parafunctional factors. Depending on this, a restorative treatment should be chosen based on the severity of the wear, as it can result in loss of vertical dimension of occlusion (VOD), tooth sensitivity, and decreased quality of life. In these cases, the choice of restoration strategy must follow evidence-based treatment protocols, which include direct and indirect restoration techniques, as well as minimally invasive treatments based on composite resins that emerge as an alternative to conventional restorations of ceramics. This clinical case describes the treatment of a patient with severe dental wear through oral rehabilitation with composite resins through direct and indirect techniques, with the aim of preserving the tooth structure as much as possible and having greater aesthetic-functional...
12
artículo
Publicado 2020
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In the present investigation we present a polysiloxane composite functionalized with silver nanoparticles (NPs-Ag). NPs-Ag was synthesized, by reduction of a silver nitrate solution (AgNO3) with sodium borohydride (NaBH4), the NPs-Ag were characterized by the UVvisible spectrophotometric method, finding that between 400 - 410 nm the typical peak of NPs-Ag by surface plasmon resonance. In the Dynamic Light Scattering (DLS) analysis of the NPs-Ag, a polydisperse distribution was found with two populations of 59.78 nm in 70% and 4.33 nm in 30%. Subsequently, the polysiloxane gel was synthesized by hydrolyzing chlorosilane, using diethyl ether as the solvent, the obtained polysiloxane was characterized by infrared Fourier transform spectrophotometry (FTIR). In the spectrum peaks are observed in the region of 1258.88 cm-1 corresponding to methyl, between 1000 - 1100 cm-1 a peak corresponding ...
13
artículo
Publicado 2017
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This work was supported by the DGCYT [MAT2015-63955-R]; the Vice-Rectorate for Research of the Pontificia Universidad Católica del Perú and the National Council of Science, Technology and Technological Innovation of Peru (CONCYTEC/FONDECYT).
14
artículo
This work studies the dependence of Cs-137 root uptake on the structure of landscape, especially on the properties of soils, under controlled conditions. Researches were carried out at various levels of Cs-137 contamination (from 20 up 1000 kBq/m²), with five different types of soils, which differ in texture and granulometric composition. The results showed that transfer factor (TF) values of Cs-137 differ 5 times for the natural grassy coenoses. The correlation between Cs-137 TF values and granulometric composition of soil was determined for both automorphic and hydromorphic mineral soils.
15
artículo
Publicado 2017
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This study describes and compares the key structural units present in water-soluble organic carbon (WSOC) fraction of atmospheric aerosols collected in different South American (Colombia – Medellín and Bogotá, Peru – Lima, Argentina – Buenos Aires, and Brazil – Rio de Janeiro, São Paulo, and Porto Velho, during moderate (MBB) and intense (IBB) biomass burning) and Western European (Portugal – Aveiro and Lisbon) locations. Proton nuclear magnetic resonance (1H NMR) spectroscopy was employed to assess the relative distribution of non-exchangeable proton functional groups in aerosol WSOC of diverse origin, for the first time to the authors’ knowledge in South America. The relative contribution of the proton functional groups was in the order H-C > H–C–C= > H-C-O > Ar-H, except in Porto Velho during MBB, Medellín, Bogotá, and Buenos Aires, for which the relative contribu...
16
artículo
Publicado 2022
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Nomophobia understood as fear of not being able to contact or make use of a smartphone, irrational fear of losing it, running out of batteries or being without an internet signal, which generates high rates of anxiety. The consumer behaviors of this virtual society lead to the postponement of personal, academic and work objectives because more time is spent performing online activities, which turn out to be more attractive and less complex. The main objective of this research has been to determine the factorial structure, validity and reliability of the Nomophobia Scale (NMPQ). 300 students participated in a State University of Metropolitan Lima. The confirmatory factor analysis corroborated a structure of four factors, showing adequate adjustment indicators composed of CFI= .997, TLI= 0.997 and RMSEA= 0.084. confirming a second-order model, plus a first-order model. Cronbach's a...
17
artículo
Publicado 2025
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The sequence of a comprehensive oral rehabilitation is described in a patient with generalized loss of tooth structure, highlighting the importance of restoring stomatognathic system function through a multidisciplinary approach. The patient was a 57-year-old woman diagnosed with occlusal disharmony, generalized attrition due to parafunction, mild dental crowding, defective restorations, carious lesions, and partial mandibular edentulism. Treatment was performed in two phases: initially, an esthetic mini-JIG was used, and occlusion was stabilized by increasing the vertical dimension using stamped composite resins restorations. In the second phase, veneers, vonlays, and implant-supported crowns were placed in the maxilla, along with a removable partial denture in the mandible, followed by delivery of a protective occlusal splint. The combination of analog and digital techniques allowed fo...
18
artículo
Publicado 2022
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Thermal regulation and ultrasound affect the physical, chemical, and antioxidant properties of essential oils and hydrosols extracted by microwaves from the leaves of Tagetes elliptica S. (chincho). The leaves were conditioned by dehydration or freezing, then pre-treated with ultrasound for 15 or 30 minutes at 40 Hz to finally obtain the essential oil (AECH) and hydrolat (HCH) through microwave extraction (500 W and 30 minutes). Yields, phenolic content, antioxidant capacity, leaf structure by optical microscopy, and chemical composition by gas chromatography and mass spectrometry (GC-MS) were evaluated. The conditioning of the leaves by freezing and sonication for 30 minutes obtained the best performance, 8.86±0.1% and 67.40 ± 4.8%, phenolic content of 39.4±0.1 mg EAG/mL and 346.2 ± 13.6 mg EAG/mL, and antioxidant capacity of 35.7 μmol EqT/mg and 0.25 μmol EqT/mg equivalent, for A...
19
artículo
El desgaste dental patológico, ocasionado por el bruxismo, es una alteración que se observa frecuentemente en la clínica odontológica. En este caso clínico fue realizado un procedimiento mínimamente invasivo, a fin de restablecer una guía anterior alterada por desgaste dental, asociado a otros tratamientos, tales como, el blanqueamiento dental y el ajuste oclusal. Este abordaje restaurador directo, asociado a las otras técnicas, posibilitó la máxima preservación de estructura dental remanente, alcanzando un excelente resultado estético y funcional, con una correcta adaptación del sistema estomatognático. MINIMALLY INVASIVE DENTISTRY FOR THE TREATMENT OF TOOTH WEARThe dental tooth wear due to bruxism is an alteration that is seen frequently in the today´s clinic. In this clinical case, a minimal invasive procedure was conducted aiming to restor...
20
artículo
The increasing demand of patients for esthetics dentistry treatments has led to the development of multidisciplinary communication between approaches among different specialties to achieve treatment success. The gummy smile is a frequent esthetic problem, which consists of excessive exposure of the gum when smiling. Treatment modalities range from gingivectomy to flap lift for the removal of excess bone. Restoration with direct veneers of composite resins is suitable for the preservation and esthetic improvement of the anterior sector, with optimal aesthetics and durability. In addition, minimally invasive treatment can be considered due to its conservative concepts of preserving the dental structure. The present case describes the treatment of a young patient with gummy smile and alteration in shape and color of the anterior teeth, through minimally invasive procedures such as gingivect...
