ALBERT

Description: It is well known that working photovoltaic (PV) plants show several maintenance needs due to wiring and module degradation, mismatches, dust, and PV cell defects and faults. There are a wide range of theoretical studies as well as some laboratory tests that show how these circumstances may affect the PV production. Thus, it is mandatory to evaluate the whole PV plant performance and, then, its payback time, profitability, and environmental impact or carbon footprint. However, very few studies include a systematic procedure to quantify and supervise the real degradation effects and fault impacts on the field. In this paper, the authors first conducted a brief review of the most frequent PV faults and the degradation that can be found under real conditions of operation of PV plants. Then, they proposed and developed an innovative Geographic Information System (GIS) application to locate and supervise them. The designed tool was applied to both a large PV plant of 108 kWp and a small PV plant of 9 kWp installed on a home rooftop. For the large PV plant, 24 strings of PV modules were modelized and introduced into the GIS application and every module in the power plant was studied including voltage, current, power, series and parallel resistances, fill factor, normalized PV curve to standard test conditions (STC), thermography and visual analysis. For the small PV installation three strings of PV panels were studied identically. It must be noted that PV modules in this case included power optimizers. The precision of the study enabled the researchers to locate and supervise up to a third part of every PV cell in the system, which can be adequately georeferenced. The developed tool allows both the researchers and the investors to increase control of the PV plant performance, to lead to better planning of maintenance actuations, and to evaluate several PV module replacement strategies in a preventive maintenance program. The PV faults found include hot spots, snail tracks, ethylene vinyl acetate (EVA) discoloration, PV cell fractures, busbar discoloration, bubbles and Si discoloration.

Description: Sustainability, Vol. 10, Pages 2413: Human Capital Sustainability Leadership to Promote Sustainable Development and Healthy Organizations: A New Scale Sustainability doi: 10.3390/su10072413 Authors: Annamaria Di Fabio José María Peiró Human resource management that aims to promote employee wellbeing calls for a new style of leadership. Such a strategy focuses on fostering flourishing and resilient workers to build up thriving businesses and robust and sustainable organizations. In this framework, we developed a new integrated construct of human capital sustainability leadership, and a scale to assess it. This leadership style has its roots in the existing definition of the term but aims to achieve higher integration of different functions and of the four dimensions of leadership, including ethical, sustainable, mindful and servant leadership. In this study, we analyze the psychometric properties of the new scale for assessing human capital sustainability leadership for Italian workers. The results of the exploratory factor analysis reveal a factor structure with the four dimensions that have good reliability and validity. The confirmatory factor analysis confirms this four-dimensional structure, which is integrated into the construct of human capital sustainability leadership as a single second-order factor.

Description: IJERPH, Vol. 15, Pages 1633: From Office Environmental Stressors to Work Performance: The Role of Work Patterns International Journal of Environmental Research and Public Health doi: 10.3390/ijerph15081633 Authors: Aida Soriano Malgorzata W. Kozusznik Jose M. Peiró Background: Different studies have shown a relationship between office environmental stressors and performance. However, studying environmental stress in the workplace requires analyzing more specific patterns to generate knowledge about the type of employees who are more or less vulnerable to environmental stressors. The present study analyzes the mediating role of health symptoms and negative emotions in the relationship between stressors and performance in different work patterns (task complexity and interactivity). Methods: There were 83 office workers (n = 603 time points) that took part in a diary study with multilevel design. Results: The appraisal of the environmental stressors is positively related to health-related symptoms, which in turn increase negative emotions, and then decrease the performance of workers who perform complex tasks and interact frequently with other people at work. This mediation is not significant when office workers do not interact frequently with other people at work and/or perform simple, rather than complex tasks. Conclusions: Work patterns play an important role when studying the mediating role of health-related symptoms and negative emotions in the relationship between the appraisal of environmental stressors and performance in office workers. In other words, employees in the ‘interactive and complex’ pattern are more vulnerable to the negative effects of office stressors on performance.

Description: Data collection is a key scenario for the Internet of Things because it enables gathering sensor data from distributed nodes that use low-power and long-range wireless technologies to communicate in a single-hop approach. In this kind of scenario, the network is composed of one coordinator that covers a particular area and a large number of nodes, typically hundreds or thousands, that transmit data to the coordinator upon request. Considering this scenario, in this paper we experimentally validate the energy consumption of two Medium Access Control (MAC) protocols, Frame Slotted ALOHA (FSA) and Distributed Queuing (DQ). We model both protocols as a state machine and conduct experiments to measure the average energy consumption in each state and the average number of times that a node has to be in each state in order to transmit a data packet to the coordinator. The results show that FSA is more energy efficient than DQ if the number of nodes is known a priori because the number of slots per frame can be adjusted accordingly. However, in such scenarios the number of nodes cannot be easily anticipated, leading to additional packet collisions and a higher energy consumption due to retransmissions. Contrarily, DQ does not require to know the number of nodes in advance because it is able to efficiently construct an ad hoc network schedule for each collection round. This kind of a schedule ensures that there are no packet collisions during data transmission, thus leading to an energy consumption reduction above 10% compared to FSA.

Description: Recent standardization efforts on low-power wireless communication technologies, including time-slotted channel hopping (TSCH) and DASH7 Alliance Mode (D7AM), are starting to change industrial sensing applications, enabling networks to scale up to thousands of nodes whilst achieving high reliability. Past technologies, such as ZigBee, rooted in IEEE 802.15.4, and ISO 18000-7, rooted in frame-slotted ALOHA (FSA), are based on contention medium access control (MAC) layers and have very poor performance in dense networks, thus preventing the Internet of Things (IoT) paradigm from really taking off. Industrial sensing applications, such as those being deployed in oil refineries, have stringent requirements on data reliability and are being built using new standards. Despite the benefits of these new technologies, industrial shifts are not happening due to the enormous technology development and adoption costs and the fact that new standards are not well-known and completely understood. In this article, we provide a deep analysis of TSCH and D7AM, outlining operational and implementation details with the aim of facilitating the adoption of these technologies to sensor application developers.

Description: IJERPH, Vol. 15, Pages 127: How Work Characteristics Are Related to European Workers’ Psychological Well-Being. A Comparison of Two Age Groups International Journal of Environmental Research and Public Health doi: 10.3390/ijerph15010127 Authors: Laura Lorente Núria Tordera José Peiró This study aimed to analyze the mechanisms through which work characteristics are related to psychological well-being, exploring the mediational role of work meaningfulness and job satisfaction, and investigating differences in the patterns of relationships between two age groups. The sample was composed of 36,896 workers from the 5th European Working Conditions Survey. Structural equation modeling analyses and multiple group analyses were performed. The results revealed a parallel mediational model, in which work meaningfulness and general job satisfaction mediate the relationships between work characteristics and well-being. Additionally, job satisfaction partially mediates the relationship between meaningfulness and well-being. These results were confirmed in both age groups (under 55 years old and older workers), but age moderates the relationships between social support and the mediating variables and the relationships between the mediating variables and general well-being. The present study uncovers significant pathways through which time pressure, decision latitude, and social support are related to psychological well-being, depicting an important step in better understanding how and when work characteristics are related to positive outcomes. It provides important clues for promoting psychosocial health at work at the European level.