Miguel Morales, Carlos Correa, Juan Antonio Porro, Carlos Molpeceres and José Luis Ocaña
Laser shock peening (LSP) is mainly a mechanical process, but in some cases, it is performed without a protective coating and thermal effects are present near the surface. The…
Abstract
Purpose
Laser shock peening (LSP) is mainly a mechanical process, but in some cases, it is performed without a protective coating and thermal effects are present near the surface. The numerical study of thermo‐mechanical effects and process parameter influence in realistic conditions can be used to better understand the process.
Design/methodology/approach
A physically comprehensive numerical model (SHOCKLAS) has been developed to systematically study LSP processes with or without coatings starting from laser‐plasma interaction and coupled thermo‐mechanical target behavior. Several typical results of the developed SHOCKLAS numerical system are presented. In particular, the application of the model to the realistic simulation (full 3D dependence, non‐linear material behavior, thermal and mechanical effects, treatment over extended surfaces) of LSP treatments in the experimental conditions of the irradiation facility used by the authors is presented.
Findings
Target clamping has some influence on the results and needs to be properly simulated. An increase in laser spot radius and an increase in pressure produces an increase of the maximum compressive residual stress and also the depth of the compressive residual stress region. By increasing the pulse overlapping density, no major improvements are obtained if the pressure is high enough. The relative influence of thermal/mechanical effects shows that each effect has a different temporal scale and thermal effects are limited to a small region near the surface and compressive residual stresses very close to the surface level can be induced even without any protective coating through the application of adjacent pulses.
Originality/value
The paper presents numerical thermo‐mechanical study for LSP treatments without coating and a study of the influence of several process parameters on residual stress distribution with consideration of pulse overlapping.
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Uroš Trdan, Sebastjan Žagar, Janez Grum and José Luis Ocan˜a
The purpose of this paper is to investigate the effect of shock waves and strain hardening effect of laser and shot peening on precipitation‐hardened aluminium alloy AA 6082‐T651.
Abstract
Purpose
The purpose of this paper is to investigate the effect of shock waves and strain hardening effect of laser and shot peening on precipitation‐hardened aluminium alloy AA 6082‐T651.
Design/methodology/approach
The hardened layer was evaluated by means of surface integrity with optical microscopy, scanning electron microscope (SEM), energy dispersive spectroscopy, analysis of microhardness and residual stress profiles. Corrosion anodic polarization tests in a 3.5 per cent NaCl water solution were carried out to express a pitting potential and the degree of pitting attack, which was verified on SEM and with 3D metrology.
Findings
Research results indicated significant differences between two treatment techniques which had an important influence on the final condition of the surface layer. Potentiodynamic polarization tests inferred that laser peening enabled shift of the pitting potential to more positive values, which ensures higher corrosion resistance.
Originality/value
Results confirmed that the higher corrosion resistance of the laser‐peened specimens against pitting corrosion depends on the modification of the surface, due to ablation during plasma generation. Despite increased surface roughness, laser‐peened specimen exhibits beneficial increase of the pitting/breakdown potential and in reduction of pitting attack degree at the specimen surface.
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Luis Lisandro López Taborda, Eduar Pérez, Daniel Quintero, José Fernando Noguera Polania, Habib Zambrano Rodriguez, Heriberto Maury and Ivan E. Esparragoza
This study aims to evaluate the impact breaking energy of the parts manufactured by the fused filament fabrication (FFF) method. The evaluation considers the use of the epoxy…
Abstract
Purpose
This study aims to evaluate the impact breaking energy of the parts manufactured by the fused filament fabrication (FFF) method. The evaluation considers the use of the epoxy resin coating, different materials and different printing orientations.
Design/methodology/approach
The authors developed an experimental statistical design using 54 experimental trials. The experiments’ output variable is the impact break energy of the parts manufactured by the FFF method. The input variables for the experiments consist of an epoxy resin coating (XTC-3D®, generic resin and without resin coating), different filament materials (nylon + carbon fiber, polyethylene terephthalate and polycarbonate) and different printing orientations (flat, edge and vertical) used. The authors carried out the tests following the EN ISO 179-1.
Findings
The use of resin coating has a significant influence on the impact energy of parts manufactured using the FFF method. The resin coating increases the impact resistance of parts processed by FFF by almost 100% of the value as compared to the parts without a resin coating. Post-processing is useful on ductile materials and increases impact breaking energy at weak print orientations.
Originality/value
This research opens a new opportunity to improve the mechanical properties of parts manufactured using the FFF method. The use of a resin coating reinforces the parts in weak print orientation.
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Jonathan Ruiz-Jaramillo, Luis José García-Pulido, Laura Montiel-Vega, Carmen M. Muñoz-Gonzalez and María Dolores Joyanes-Diaz
Heritage landmarks and historical values often coexist with places and regions of remarkable environmental and landscape wealth. This article studies their capacity to generate…
Abstract
Purpose
Heritage landmarks and historical values often coexist with places and regions of remarkable environmental and landscape wealth. This article studies their capacity to generate global understanding of their territory through the creation of cultural routes. The proposed methodology is verified through the study of the defensive features of the ancient Nasrid Kingdom, the last Islamic territory in the Iberian Peninsula from the thirteenth to the fifteenth century, which shaped the Spanish region known as the Kingdom of Granada until the nineteenth century.
Design/methodology/approach
To assist in the proposal of new routes, a precise collection of physical data (topography, landmarks, resources, population centres …), existing public paths and protected natural sites was carried out. Those cultural routes relevant to the area of study were also selected and mapped through GIS. A set of indicators prioritised through an analytic hierarchy process (AHP) have evaluated the proposed itineraries.
Findings
The methodology enables the integral evaluation of parameters such as natural heritage, existing paths networks, defensive architectural heritage (watchtowers), existing cultural routes or proximity to basic services. The methodology's application allows an index to be obtained that quantifies the global implications of these parameters in the design of new itineraries. This leads to the development of a network with its own narrative that provides a historical, environmental and cultural meaning.
Originality/value
Watchtowers in this region have previously been studied as isolated and locally relevant architectural features. This work studies them from an overall perspective, considering each tower as a piece of a complex defensive and territorial system. Cultural routes arise from this joint interpretation as tools to restore and highlight the interrelationship between architectural heritage and territory and people.
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Edna Carolina Sastoque-Ramírez
This article studies how the Regenerative Government (1880–1903) in Colombia positioned monetary policy as one of the central subjects in the political arena by the end of the…
Abstract
This article studies how the Regenerative Government (1880–1903) in Colombia positioned monetary policy as one of the central subjects in the political arena by the end of the nineteenth century, and how the struggles of this attempt transformed the political economy of the period. In the background of the monetary, debates were some relevant characteristics: the country was facing serious difficulties as a consequence of an uneven integration of sectors to international trade, the de facto bimetallic regime, the formation of conglomerates of regions, and the difficulty of implementing paper money. Facing this situation, the Regenerating Governments found themselves in the need of imposing monetary and credit rules. They attempted to implement the scientific rules prevailing at the time and the possibilities that the national reality allowed them. As a consequence, the interests of the merchant elites and bankers had eroded the existing free banking system. Some bankers took advantage of the situation of the dubious management that the State gave to the monetary issue and succeeded on speculative finance increasing their wealth. Others, on the other hand, tried to strengthen their relations with the State. In this perspective, this article will synthesize the main aspects by agents of the debate between free banking and forced course.
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André Luís Policani Freitas, Gustavo Antonio Pessanha Monteiro and Helder Gomes Costa
Despite existing advances in information technology infrastructure services (ITISs), there remains no consensus in the literature regarding what dimensions or criteria are best…
Abstract
Purpose
Despite existing advances in information technology infrastructure services (ITISs), there remains no consensus in the literature regarding what dimensions or criteria are best suited for the measurement of their quality. The purpose of this paper is to fill this gap, proposing a methodological approach to measuring the quality of ITISs, as perceived by users.
Design/methodology/approach
Cronbach’s α and item-total correlations were used to measure the reliability of the questionnaire; multiple linear regression analysis was employed to determine the items (criteria) most related to the quality of ITISs; and finally, importance–performance analysis was conducted to determine the most critical criteria in service provision. An exploratory study was conducted to evaluate the quality of ITISs at a Brazilian university.
Findings
Control of the activities of the information technology (IT) team, periodic maintenance of hardware and software, the security policy and the skill of the labor affect the quality of services most, relative to the dimensions of infrastructure, people and processes.
Practical implications
The results indicate what dimensions and items should be considered by IT managers to improve the quality of ITISs. Special attention should be paid to the effective use of equipment, software and network infrastructure: it should be ensured that these are in good working order and can be utilized by users who expect to be trained to take advantage of their functions.
Originality/value
This paper shows how to integrate relevant techniques to assess the quality of ITISs. An original set of criteria to evaluate the quality of ITISs, derived from a systematic review of the literature, is suggested.
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María Higueras, Ana Carrasco-Huertas, Ana Isabel Calero-Castillo, Manuel Moreno Alcaide and Francisco José Collado Montero
This paper aims to study the suitability of a selection of 3D printing liquid photopolymer resins for their application in the cultural heritage context.
Abstract
Purpose
This paper aims to study the suitability of a selection of 3D printing liquid photopolymer resins for their application in the cultural heritage context.
Design/methodology/approach
The main concerns regarding the conservation and restoration of cultural assets are the chemical composition and long-term behavior of the new materials that will be in contact with the original object. Because of this, four different LED curing resins were exposed to an accelerated aging procedure and tested to identify the materials which demonstrated a better result. Some specific properties of the material (color, glossiness, pH and volatile organic compound emissions) were measured before and after the exposure.
Findings
Some of the properties measured reported good results demonstrating a decent stability against the selected aging conditions. The main changes were produced in the colorimetric aspect, probably indicating other chemical reactions in the material. Likewise, a case study could be also executed to demonstrate the usefulness of these materials in the cultural field.
Research limitations/implications
It is necessary to study in more detail the long-lasting behavior of the materials employed with these technologies. Further analysis should be carried out highlighting the chemical composition and degradation process of the materials proposed.
Originality/value
This paper contributes to the introduction of curing 3D printing resins in the restoration methodologies of cultural assets. For this, the study of a selection of properties represents the first stage to suggest or reject their use.
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Guiselle M. Romero-Lora, Juan C. Rivero-Isla and Brenda E. Lopez-Chavez
During the COVID-19 pandemic, Local Educational Management Units (UGELs), the key government stakeholders in the provision of education services in Peru, implemented responsive…
Abstract
Purpose
During the COVID-19 pandemic, Local Educational Management Units (UGELs), the key government stakeholders in the provision of education services in Peru, implemented responsive interventions. This paper analyses the relationship between UGEL organisational resilience and their responses during this period.
Design/methodology/approach
A survey was conducted to measure UGEL management practices, with 251 valid responses from directors and managers. Based on organisational resilience theory, 67 questions were grouped into 13 factors and 3 components: (1) leadership and organisational culture, (2) preparation for change, and (3) networks building on the Organisational Resilience Index (ORI). These factors correlated with the number of interventions and the impact of those interventions implemented by UGELs.
Findings
The findings indicated that of all ORI components, leadership and organisational culture ranked the highest. Moreover, the ORI is positively associated with the number of interventions and the perceived impact produced by those interventions. Interestingly, it was found that when the gender variable is included in the correlation between the ORI and the number of interventions, women leading UGELs display a higher number of interventions than their male counterparts; and the coefficient increases even more when women lead a UGEL in a more challenging context (i.e., when the UGEL is located in a low-income area and operates under scarce resources).
Originality/value
This is the first study in Peru which analyses organisational resilience in the education sector, specifically about UGELs during the COVID-19 pandemic. It may help set priorities for institutional strengthening initiatives aimed at improving organisational resilience, which is particularly important in such uncertain and changing contexts.