Search results for "lead"
showing 10 items of 1360 documents
New Insight on Archaeological Metal Finds, Nails and Lead Sheathings of the Punic Ship from Battle of the Egadi Islands
2023
The wreck of the Punic ship exhibited at the Archaeological Park of Lilybaeum (Marsala, Italy) is a unique example in the world. In this paper, the investigation of some metal finds (30 nails and 3 fragments of sheathings) belonging to the wreck of the Punic ship is reported. Portable X-ray fluorescence and Raman spectroscopy allowed us to identify the elements and compounds constituting them and make some deductions about their composition. X-ray diffractometry, polarised optical microscopy and scanning electron microscopy of the collected micro-samples allowed us to explain the degradation that occurred in the underwater environment.
One-dimensional nanostructures of lead and lead dioxide for application in lead-acid batteries
2010
Fabrication of Pb and PbO2 nanostructures was undertaken with the aim of building low cost lead acid micro-batteries with high performance. Despite environmental problems and the relatively low specific energy in comparison with other galvanic generators, lead acid batteries are still extensively used in the field of energy accumulation, owing to a well known and reliable technology. Thus, it is of high technological interest to develop procedures for fabricating these devices at a micrometer scale or less. PbO2 nanowires were grown in different electrochemical deposition conditions leading to pure -PbO2, pure -PbO2 and mixture [1-2]. Several parameters, like temperature, electrolyte…
The Effect of Dopants on Sintering and Microstructure of Lead-free KNN Ceramics
2011
Lead-free potassium sodium niobate (K0.5Na0.5)NbO3 (KNN) has been prepared via conventional ceramic processing method. The influence of 0.5 wt% - 1.5 wt% MnO2 and WO3 addition on the sintering, crystallographic structure, microstructure and dielectric properties of KNN has been investigated. Optimal sintering temperatures of KNN ceramics were observed to be in the narrow interval: 1090 °C - 1110 °C for MnO2 doped KNN; 1150 °C - 1170 °C for pure KNN and doped with WO3. XRD patterns showed that all the samples have single perovskite structure with monoclinic structure. Microstructure of ceramics was changed greatly by using dopants.http://dx.doi.org/10.5755/j01.ms.17.1.251
MANAGING THE LEADERSHIP CHALLENGES
2010
Even if since ancient times wealth and power have been associated with having physical resources, and the traditional production factors were predominantly physical, knowledge revolution is the shift from physical-based economy to predominantly knowledge-based economy. Experts have lately noticed the increase of economic importance of technologies, information, economic processes, human capital, the organisation’s abilities and skills, each of these factors having a significant importance to the knowledge management. It is expected that future wealth and power shall mainly be derived from intangible intellectual resources, from the knowledge capital. This is why we considered it of absolute…
Incoherent Yet Still Moral? Followers’ Perceptions of Their Leaders’ Integrity
2022
The aim of this study was to broaden the current understanding of leader integrity by applying a social-cognitive process model to leaders’ moral decision-making. Leaders (n = 223) were classified into different integrity styles (informational, normative, or diffuse-avoidant) based on their personal descriptions of how they approach moral questions and make moral decisions at work. We then investigated how followers (n = 963) perceived these leaders’ integrity (moral behavior, behavioral integrity, and consistency) and their leader-member exchange (LMX) quality by using a hierarchical leader-follower sample. Followers evaluated normative leaders to show the highest amount of consistency com…
LMX and Well-Being: Psychological Climates as Moderators of their Concurrent and Lagged Relationships
2020
The importance of the quality of leader member exchange (LMX) for workers’ health and well-being is acknowledged in the literature, and empirical research addressing this issue is beginning to accumulate. However, recent reviews on this topic recommend making a greater effort to include time and boundary conditions in this relationship. The present study aims to analyze the effects of LMX on employees’ well-being, and the moderating role of psychological climate, by means of a longitudinal study with a 12-month time lag. Data were obtained from 119 employees working in the Public Health Service . Results show that LMX had concurrent and lagged positive effects on well-being. Perceptions of …
Leader-Member Exchange, Transformational Leadership, and Value System
2005
This study looked at the relationship between leader-member exchange (LMX), transformational leadership, and terminal and instrumental value system congruence between leader and follower, and their relative impact on four outcomes, using a sample of 100 pairs of managers and subordinates from a non-profit organization in the United States. The four outcomes studied are perceived effectiveness of leader and work unit, follower satisfaction with leader, follower’s motivation to put in extra effort, and follower’s intention to quit the organization. Results of correlation analyses indicate that LMX is positively related to transformational leadership, which in turn is positively related to ter…
Focalisation sur le leadership collaboratif
2017
Des chercheurs suggerent que la gestion des defis et des changements de plus en plus nombreux ainsi que la resolution de problemes complexes en education pourraient etre facilitees par le leadership collaboratif. Ainsi, le present article vise a eclaircir le concept de leadership collaboratif et, plus precisement, ii repond aux questions suivantes : Qu'est-ce que le leadership collaboratif? Qu'est-ce que le modele TenKeys* (dix clés) propre au leadership collaboratif? De quelle facon le leader peut-il faire preuve de leadership collaboratif? Quels sont les effets du leadership collaboratif selon les recherches effectuees? Par l'entremise de ces questions, nous ferons egalement valoir que l…
Shed vesicles are involved in the release of some leaderless proteins.
2006
Most proteins destined for secretion in the extracellular matrix are characterized by the presence of N-terminal signal peptides which direct their translocation into the endoplasmic reticulum, they are subsequently transferred to the Golgi apparatus and then secreted in the extracellular space. A growing number of secreted proteins, are being identified which, however, lack signal peptides allowing their entrance into the endoplasmic reticulum. They include the inflammatory cytokine interleukin 1b, galactins, macrophage migration inhibitory factor (MIF), acid and basic fibroblast growth factors (FGF-1, FGF-2) and Sphingosine kinase1(SphK-1). These proteins are secreted from the cell by unc…
Conglomerate Diversification and Strategic Leadership : allocation, management, and reconfiguration of resources at General Electric Co.
2017
leadership conglomerate diversification