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Els empresaris turístics de Costa Brava, Costa Daurada, Terres de l'Ebre i Lleida-Pirineus, davant el futur del sector
No full textEs tracta d'establir la visió dels directius turístics catalans sobre si s'ha de modificar el ritme de creixement actual del sector, si s'ha de limitar o s'han de prendre determinades mesures per apaivagar-lo. L'estudi s'ha focalitzat en quatre destinacions turístiques catalanes: Girona-Costa Brava (G-CB), Costa Daurada (CD), Terres de l'Ebre (TdlE), i Lleida-Pirineus (Ll-P), en les quals s'ha realitzat un seguit de dinàmiques de grup amb empresaris del sector i a la vegada s'han recollit 96 respostes a un qüestionari enviat. A partir de les valoracions obtingudes referides a un seguit d'indicadors, s'ha pogut establir que, excepte G-CB, que estaria disposada a revisar la situació, la resta de les destinacions no vol canviar de model de negoci
El repte del finançament de la dependència a Catalunya mitjançant l’avançament dels lloguers, mantenint la propietat de l’habitatge
No full textEl fort impacte demogràfic a curt termini derivat dels augments del nombre de persones grans i de l’esperança de vida planteja un escenari sense precedents pel que fa al finançament de les depeses que requereixen les persones més grans, amb dependència. En aquests darrers anys de la vida cal fer front a un augment molt important de les despeses, que no es poden assumir amb els ingressos recurrents de les pensions. Aquest fet, conjuntament amb la manca de previsió individual i les limitacions de les administracions per donar aquesta cobertura, plantegen la necessitat de cercar noves alternatives. La proposta plantejada en aquest treball consisteix en una innovació que pot ajudar a donar sostenibilitat al sistema, ja que un elevat percentatge dels ciutadans disposen d’un habitatge en propietat susceptible de facilitar la liquiditat necessària mitjançant l’avançament de lloguers per fer front al pagament de les despeses de la dependència
Aplicació de la metodologia Random Forest en la detecció de maquillatge comptable: Un estudi empíric.
No full textAquest treball investiga la problemàtica de la manipulació comptable. En concret, té l'objectiu d'identificar variables quantitatives i qualitatives que permetin distingir a les empreses maquilladores de les no maquilladores. Per a això, s'utilitza la metodologia Random Forest. A partir d'una mostra equilibrada de 80 empreses, la meitat de les quals han estat identificades com a manipuladores comptables i l'altra meitat identificades com a susceptibles de no haver manipulat els seus estats comptables, s'analitzen un total de 47 senyals d'alerta, tant quantitatives com qualitatives. D'aquesta forma, es determinen quines són les més rellevants a l'hora de discriminar entre tots dos grups. Els resultats permeten tenir més coneixement sobre els senyals d'alerta relacionades amb la manipulació comptable. Aquesta recerca pot ser de gran interès per als usuaris de la informació financera de les empreses, entre els quals podem destacar a: directius, accionistes, inversors, creditors, competidors, analistes bancaris, analistes d'inversió, auditors… així com per a organismes supervisors
Qualitat de l'ocupació industrial
Get PDFLa indústria ha estat tradicionalment un sector motor de l’economia catalana, i és objectiu compartit recuperar el protagonisme d’antuvi donada la seva capacitat tractora, impulsora de la innovació i la competitivitat i on els factors productius poden tenir millors retribucions gràcies als guanys de productivitat. Des de 2023 l’ocupació industrial ha anat creixent fruit d’una recuperació notable de l’activitat industrial en termes de creixement del VAB. Els darrers resultats, del tercer trimestre de 2024, mostren, però, una evolució dispar per subsectors industrials. Sigui com sigui, és essencial vetllar perquè l’ocupació que es generi en el sector sigui de qualitat, amb bones condicions de treball. Aquest informe pretén fer una revisió dels nivells de qualitat en la indústria en contraposició als altres grans sectors econòmics a partir de l’anàlisi de diferents indicadors laborals, com la temporalitat o els salaris, que aproximen aquest concepte de la qualitat, tan difícil d’objectivar i mesurar. Paraules clau:Indústria, qualitat de l’ocupació, temporalitat, salaris, sinistralitat laboral
Fatigue delamination damage analysis in composite materials through a rule of mixtures approach
Get PDFThe present study investigates delamination damage initiation and propagation within a homogenization theory of mixtures, using the concept of virtual layers and virtual interfaces. It eliminates spatial discretization of layers, introducing a resultant damage variable to capture structure’s bulk response under both monotonic and cyclic loads. Fatigue-induced deterioration is classified into sub-critical, critical, and over-critical stages based on interfacial stresses. Calibration is conducted employing the widely-available Wöhler curves for each loading mode independently. An advance-in-time strategy is included in the model to enhance the simulation speed. The reliability of the approach is assessed for crack initiation and propagation separately through standard test coupons, showing good correlation with experimental data in mode I, mode II, and mixed-mode loading conditions. Depending on the calibration procedure adopted, the model is applicable to a wide range of stress ratios. In addition, it could be integrated into any standard finite element framework using the desired number of elements through the thickness regardless of the physical amount of layers. This allows easy modification of stacking sequences or the number of layers within the constitutive law without mesh structure changes, facilitating simulation of large-scale composite laminates with minimal accuracy loss and reduced computational costs
Characterization of composite joints welded by electrical resistance. Effect of processing parameters.
No full textOne of the main advantages of using reinforced thermoplastic materials is the possibility of joining different parts by welding. Welding process avoids the use of mechanical joints, which increase the weight of the component and the manufacturing time; as well as adhesive joints, where it is difficult to ensure their quality.
Welded joints are of special interest when applied in assembly processes with a high production rate. However, welded joints on high-rate components require research into new materials, processes, and inspection techniques. In this line, the present work analyzes the results obtained from different welded joints through heating by electrical resistance without contact. This characterization study includes mechanical, microstructural and physical-chemical properties analysis, as well as its evaluation through non-destructive inspection techniques. As a result, a deeper knowledge of the materials and processes has been obtained, including the effect of the different welding processing parameters.
Different opening mode mechanical tests are presented in this study, as well as thermal analysis by differential scanning calorimetry to evaluate the effect of temperature and time applied during the welding process on the final properties. The quality of the process in the different joining elements has been verified with inspection by means of infrared thermography, correlating indications in the level of IR radiation with localized variations microscopy features (i.e.: amount of resin). In addition, a microstructural study has been carried out to assess the fiber/resin content of the material in the joint areas, as well as a complementary analysis using computed tomography and ultrasound
CHARACTERISATION OF MODE II INTERLAMINAR FRACTURE UNDER FATIGUE
No full textIt is essential to understand the behavior of composite laminates against fatigue crack initiation and growth in order to accurately predict component service life and to establish safe maintenance periods.
In this work, an extrapolation procedure to characterize the mode II fatigue behavior based on the J0i-C0i and Δ0i-C0i master curves is presented and validated.
The extrapolation procedure, based on the compliance variation, assumes that all effects associated with damage are included in the equivalent crack length. In this method, new factored expressions for flexibility (C0i), Integral-J (J0i) and crack tip displacement (Δ0i) are defined and according to their polynomial expressions with respect to the equivalent crack length, invariant relationships between J0i-C0i and Δ0i-C0i are obtained for a given material system and test configuration.
Once the master curves have been calibrated, the extrapolation procedure allows characterizing the fatigue behavior of a material system by determining the Paris law during the fatigue test, monitoring only the test flexibility and the maximum load with respect to the number of cycles
Development of manufacturing processes of hybrid structures made of recycled thermoplastic material with unidirectional inserts
No full textOne of the most important challenges in the automotive field is to deal with the new regulations regarding the material’s recycling, following the guidelines of the Circular Economy, without losing properties. The hybridization of parts of recycled material combined with continuous fiber inserts could be a solution to this problem. Within the framework of the ZeKonp project, a study and optimization of the manufacturing process variables of compression moulding of hybrid structures with unidirectional tape inserts. has been carried out
The starting material has been a plate of a semi-finished hybrid of GMT material obtained by scraps of UD tape from production waste. The reinforcement has been placed with a Multilayer automatic taping equipment.
In order to optimize the process, variables such as the arrangement of the material, temperature and compaction pressure, the strategy and speed of deposition of the strips and the welding process of the materials have been studied.
In addition to the reuse of the materials, the process and life cycles of the final product has also been taken into account in order to reduce the environmental impact throughout its life cycl
CHAPTER 7: RECYCLING AND RECOVERY TECHNOLOGIES OF CARBON AND GLASS FIBERS BY PYROLYSIS
No full textOf all the recycling technologies available for recycling fiber-reinforced composite materials, pyrolysis is one of the most frequently used. This technology allows the recovery of long fibers with good mechanical properties in addition to reusing the resin in the form of energy. This chapter describes this technology, including some variations of it, such as microwave-assisted pyrolysis. It can be concluded that pyrolysis is a suitable technology for the recovery of long fibers, maintaining between 70-95% of their initial mechanical properties. Furthermore, pyrolysis applied to reinforced composites is a technology currently used at an industrial level, both in Europe and in Spain