Search results

This study aims to carry out an investigation of design approaches that should be used for the design of unconventional, innovative transmission system for construction yards to privilege a smooth behaviour efficiency, and the use of innovative production techniques. Results are quite surprising, as with a proper method it is possible to demonstrate that a cycloidal drive with Wolfrom topology should be an interesting solution for the proposed application.

With a functional approach, also considering materials and specifications related to the investigated application, it is possible to demonstrate that possible optimal solutions should be quite different respect to the ones that can be suggested with a conventional approach. In particular for proposed applications constraints related to encumbrances, the choice of new material has led to the innovative unconventional choice of a Wolfrom cycloidal speed reducer.

Provided solution is innovative respect current state of the art for machine currently used in construction yards: in terms of adopted transmission layout; in terms of chosen materials, resulting in an innovative solution.

Current research has strong implications on the adoption of polimeric materials for the construction of reliable transmission for harsh industrial environment as the proposed case study (concrete mixer for construction yard).

Proposed transmission system is absolutely original and innovative respect current state of art also considering proposed materials and consequently production methods. This is an example of transmission designed to be built with polymeric materials by optimizing chosen topology respect to chosen material.

This paper aims to examine the short-term effect of the Arizona Immigration Law of 2010 (SB 1070) on the noncitizen Hispanic state population.

To get a consistent estimate of this effect, a synthetic control method has been used to calculate a suitable counterfactual.

Results indicate that this bill produced a statistically significant short-term reduction in the proportion of noncitizen Hispanics in Arizona between 10 and 15 per cent. However, the evidence suggests that this effect vanishes after a few months.

These findings are consistent with previous evidence of the high mobility of the undocumented population in the US, and contribute to the understanding of the effects of federal and state-level immigration legislation.

Este artículo examina el efecto a corto plazo de la Ley de Inmigración de Arizona de 2010 (SB 1070) sobre la población hispana no ciudadana.

Para obtener una estimación consistente sobre este efecto, he utilizado un método de control sintético para calcular una hipótesis de contraste adecuada.

Los resultados indican que este proyecto produjo una reducción a corto plazo estadísticamente significativa en la proporción de hispanos no ciudadanos en Arizona —entre el 10% y el 15%—. Sin embargo, la evidencia sugiere que este efecto desaparece después de unos meses.

Estos hallazgos son consistentes con la evidencia previa de la alta movilidad de la población indocumentada en los Estados Unidos, y contribuyen a la comprensión de los efectos de la legislación de inmigración federal y estatal.

Población hispana, Inmigración ilegal, Control sintético

Artículo de investigación

The main purpose of the present study was to improve and develop previously proposed models for Iran telecommunication networks. It should be noted that the six-dimensional (6D) sustainability model used in this study will be a useful and comprehensive model for industries. Since, the new dimension of IT along with the five well-known economic, social, environmental, technical and institutional aspects of organizations is considered to have great impacts on supply chain sustainability; the proposed framework can be practical.

According to the related literature review, there are two research streams in supply chain management. The first stream is exploratory research, seeking out conceptual discussions in this area. The second one is associated with mathematical models and techniques, aiming to set decision-making rules in this regard (Agrell et al., 2004). In this study, evaluation was performed using the FMEA method as an analytical technique based on the principle of pre-occurrence prevention to identify potential failure factors in sensitive systems (Mohammadfam and Kianfari, 2008).

After identifying the risks and causes of the incidence and effects and consequences of risks, preventive and risk control measures and advisory strategies were presented. Customers with 45.76% share in critical risks are threatening to maintain supply chain in these companies. During this study, it was found that 33.9% of the main source of supply chain critical risks was customers, constituting 45.76% of such risks, accompanied by organization, having a 38.88% share of critical risk generation. The study findings also revealed that 33.9% of critical risks were mainly (equally) related to economic and technical aspects of supply chain sustainability in telecommunication networks. Moreover, as a newly-introduced sixth dimension, IT represented 10.17% of critical risks threatening supply chain sustainability in such networks. Critical risks are mainly related to the economic and technical aspects (equally) with the sustainability of the telecommunication networks supply chain. Also, as a new finding and the sixth dimension, 10.17% of the critical risks that threaten the sustainability of the telecommunication networks supply chain have the information technology dimension.

The internet and fixed and mobile data services are provided by several private companies in Iran, which are relatively similar in terms of their supply chains. In order to manage the sustainability of Iran's telecommunication supply chain, telecommunication networks affiliated to Iran Telecommunication Company (ITC), operating in the field of data and internet services and fixed telephone were selected in 31 provinces. The intended networks were also providing an important part of the country's needs including Mobile Telecommunication Company of Iran, a subsidiary of Iran's telecommunication networks, as one of the top companies in this industry. Accordingly, all the networks studied in this study needed to be identified with regard to communication sustainability risks, since they provide management solutions to each other by segregating risks. In this study, 68 managers and 72 experts participated in different work teams of telecommunication networks.

Polymer laser powder bed fusion (PBF-LB/P) is an additive manufacturing technology that is sustainable due to the possibility of recycling the powder multiple times and allowing the fabrication of gears without the aid of support structures and subsequent assembly. However, there are constraints in the process that negatively affect its adoption compared to other additive technologies such as material extrusion to produce gears. This study aims to demonstrate that it is possible to overcome the problems due to the physics of the process to produce accurate mechanism.

Technological aspects such as orientation, wheel-shaft thicknesses and degree of powder recycling were examined. Furthermore, the evolving tooth profile was considered as a design parameter to provide a manufacturability map of gear-based mechanisms.

Results show that there are some differences in the functioning of the gear depending on the type of powder used, 100% virgin or 50% virgin and 50% recycled for five cycles. The application of a groove on a gear produced with 100% virgin powder allows the mechanism to be easily unlocked regardless of the orientation and wheel-shaft thicknesses. The application of a specific evolutionary profile independent of the diameter of the reference circle on vertically oriented gears guarantees rotation continuity while preserving the functionality of the assembled mechanism.

In the literature, there are various studies on material aging and reuse in the PBF-LB/P process, mainly focused on the powder deterioration mechanism, powder fluidity, microstructure and mechanical properties of the parts and process parameters. This study, instead, was focused on the functioning of gears, which represent one of the applications in which this technology can have great success, by analyzing the two main effects that can compromise it: recycled powder and vertical orientation during construction.

The purpose of the study was to test the usability of the MyLA app prototype by its potential users. Furthermore, the Web app will be introduced in the framework of “Mobile Learning Analytics”, a cooperation project between the Cooperative State University Mannheim and University of Mannheim. The participating universities focus on the support of personalized and self-regulated learning. MyLA collects data such as learning behavior, as well as personality traits. Last but not least, the paper will contribute to the topic of learning analytics and mobile learning in higher education.

For the empirical investigation, a mixed-method design was chosen. While 105 participants took part in the conducted online survey, after testing the app prototype, seven students joined an additional eye tracking study. For the quantitative part, a selected question pool from HIMATT (highly integrated model assessment technology and tools) instrument was chosen. The eye tracking investigation consisted of three tasks the participants had to solve.

The findings showed that the students assessed the idea of the app, as well as the navigation positively. Only the color scheme of the prototype was not very attractive to a noticeable amount of the participants. So, it requires slight modifications concerning the app design. For the eye tracking study, it can be stated that the students viewed the relevant parts, and they basically had no difficulties to solve the tasks.

Due to the empirical testing of the app prototype, the project team was able to adjust the application and to add further features. Furthermore, the backend was programmed and an additional tool (MyLA dashboard) was developed for lecturers. A mutual understanding of the targets, privacy issue and relevant features are indispensable for further development of the project.

A global trend of type 2 diabetes prevalence is rising. Preventing and managing of systemic and dental complications is crucial to decrease negative effects on glycemic control. The purpose of this paper is to estimate the efficacy of Brief Lifestyle Change in conjunction with Dental Care (Brief-LCDC) Programs to decrease glycemic level and improve periodontal status in patients with type 2 diabetes.

Health Center 54 conducted randomized controlled trial among 192 patients (96 intervention and 96 control) from February to August 2018. Group education for lifestyle modification, individual oral hygiene instruction and lifestyle counseling by motivational interviewing was provided to the intervention group at baseline. Motivation of lifestyle modification every month by multimedia was also provided to the intervention group. The usual program was provided to the control group. At baseline and a six-month follow-up, glycemic level and periodontal status were assessed from participants. Data were analyzed by descriptive statistic, t-test, χ² test, Fisher’s exact test, Repeated measure ANOVA and multiple linear regression.

Glycemic level and periodontal status were lower in the intervention group than the control group at the sixth-month followed up with statistical significances. Glycemic level and periodontal status had negatively correlated to intervention group with statistically significant.

Brief-LCDC Program which incorporated lifestyle modification and oral health care had efficacious to decrease glycemic level and improve periodontal status in patients with type 2 diabetes. Early prevention program by Brief-LCDC Program is crucial to prevent dental complications.

Buckling should be carefully considered in steel assemblies with members subjected to compressive stresses, such as bracing systems and truss structures, in which angles and built-up steel sections are widely employed. These type of steel members are affected by torsional and flexural-torsional buckling, but the European (EN 1993-1-2) and the American (AISC 360-16) design norms do not explicitly treat these phenomena in fire situation. In this work, improved buckling curves based on the EN 1993-1-2 were extended by exploiting a previous work of the authors. Moreover, new buckling curves of AISC 360-16 were proposed.

The buckling curves provided in the norms and the proposed ones were compared with the results of numerical investigation. Compressed angles, tee and cruciform steel members at elevated temperature were studied. More than 41,000 GMNIA analyses were performed on profiles with different lengths with sections of class 1 to 3, and they were subjected to five uniform temperature distributions (400–800 C) and with three steel grades (S235, S275, S355).

It was observed that the actual buckling curves provide unconservative or overconservative predictions for various range of slenderness of practical interest. The proposed curves allow for safer and more accurate predictions, as confirmed by statistical investigation.

This paper provides new design buckling curves for torsional and flexural-torsional buckling at elevated temperature since there is a lack of studies in the field and the design standards do not appropriately consider these phenomena.

The purpose of this paper is to review possibilities of implementing ceramic additive manufacturing (AM) into electronic device production, which can enable great new possibilities.

A short introduction into additive techniques is included, as well as primary characterization of structuring capabilities, dielectric performance and applicability in the electronic manufacturing process.

Ceramic stereolithography (SLA) is suitable for microchannel manufacturing, even using a relatively inexpensive system. This method is suitable for implementation into the electronic manufacturing process; however, a search for better materials is desired, especially for improved dielectric parameters, lowered sintering temperature and decreased porosity.

Relatively inexpensive ceramic SLA, which is now available, could make ceramic electronics, currently restricted to specific applications, more available.

Ceramic AM is in the beginning phase of implementation in electronic technology, and only a few reports are currently available, the most significant of which is mentioned in this paper.

The post-operative management of flexor tendon injuries has been the focus of considerable exploration and there continues to be variation in approaches and methods of mobilisation. The purpose of this paper is to explore therapy management following repair to flexor tendons at zone II and flexor pollicis longus (FPL) (all zones) in Ireland.

A descriptive survey questionnaire design through an online format was used. Therapists were recruited through the Irish Association of Hand Therapists, the national bodies for occupational therapy and physiotherapy, and therapy managers in acute hospitals, with 29 therapists participating in the study. Descriptive statistics were used to analyse the survey data.

Patients were generally seen three to five days following surgery. Early active mobilisation approaches were favoured by all but one therapist, with 62% using the Belfast protocol and 34% the Manchester Short Splint (MSS) protocol. Each early active protocol exercise session commences with passive motion followed by graded active flexion. Tenodesis is incorporated by the majority of respondents within the first four weeks. Therapy programme and splints are modified based on patient presentation. Resistance exercises are commenced from week seven. Patient compliance was identified as the most influential factor in the post-operative intervention approach taken.

This study provides the first Irish profile of current practice in the post-operative management of flexor tendon repairs at zone II and FPL which has not previously been reported. Further research should explore the reasoning behind the interventions chosen and also the implications for practice of changes to surgical techniques.

This study aims to analyze the role of corporate social responsibility (CSR) customer perceptions, customer–company identification and customer trust on customer engagement (CE), paying special attention to the moderating effects of two types of social media communication, firm-generated content and user-generated content.

The study uses a mixed-methods’ approach. First, a single-factor experiment using Twitter posts as stimuli with 227 hotel guests. The structural model was analyzed using SmartPLS 3.2.7. Second, structured in-depth interviews were undertaken with three hotel industry experts to complement the conclusions of the quantitative study.

The results show that when a customer trusts a hotel and identifies with its corporate values, CSR tweets generate CE toward the hotel. CSR communications made by customers reinforce the impact of CSR tweets on customer trust more than CSR tweets posted by hotels. Hotel industry experts give insights to explain these results in different types of hotels.

CSR communications made through Twitter affect customers’ perceptions of a hotel’s CSR activities and customer trust in hotels, especially if they originate from a source external to the company. This result can be of use for hotel managers who have not previously given importance to active CSR communications or the interactivity of social media.

The authors show the moderating effect of user-generated content in the relationship between CSR customer perceptions and customer trust, thus contributing to the research into the effectiveness of social media. They use a mixed-methods’ approach to increase the validity of the results.

Este estudio analiza el papel de las percepciones de RSC, la identificación cliente-empresa (CCI) y la confianza en el engagement del cliente (CE), prestando especial atención al efecto moderador de dos tipos de comunicación en redes sociales: Contenido Generado por la Empresa (FGC) y Contenido Generado por el Usuario (UGC).

Se emplean métodos mixtos: un experimento de un factor usando publicaciones de Twitter como estímulo con 227 huéspedes del hotel, cuyo modelo estructural se analizó con SmartPLS 3.2.7., y 3 entrevistas en profundidad con expertos de la industria hotelera.

Los resultados muestran que, cuando un cliente confía en el hotel y se identifica con sus valores corporativos, los tweets de RSC generan engagement. La comunicación de RSC emitida por usuarios refuerza el impacto de los tweets de RSC en la confianza del cliente más que los tweets publicados por hoteles. Los expertos de la industria hotelera aportan nociones para explicar estos resultados en diferentes tipos de hoteles.

La comunicación de RSC realizada a través de Twitter afecta las percepciones del cliente sobre las actividades de RSC del hotel y la confianza en el mismo, especialmente si proceden de una fuente externa a la empresa. Este resultado puede ser útil para gerentes de hoteles que no se benefician de la comunicación activa de RSC o la interactividad de las redes sociales.

Se valida el efecto moderador del UGC en la relación entre las percepciones de RSC y la confianza de los clientes, contribuyendo así a la investigación sobre la efectividad de las redes sociales. Se emplea un diseño mixto para incrementar la validez de los resultados.

Comunicación de RSC, Engagement del Consumidor, Fuente del mensaje, Contenido generado por la empresa, Contenido generado por el usuario, Twitter, Compromiso con el cliente

Trabajo de investigación