521 research outputs found
Development of bioplastics from agro-wastes
During centuries synthetic polymers have been used in a variety of applications in the everyday of human
life. They became essential due to its versatility, durability and low cost [1]. However, due to their excessive
use, several drawbacks as its resistance to the decomposition, toxicity after incineration and accumulation in
the environment induce negative ecological impact in landfills and water contamination [2]. Moreover,
plastics production implies the use of non-renewable resources, such as, oil and natural gas that represents
about 8 % of global consumption [1,2]. Therefore, become crucial to search for new ecological materials
toward innovative and cost-effective fabrication of environmentally degradable plastics demonstrating
similar performance to conventional ones [1,3]. Simultaneously, the high amount of agro-wastes generated
from food industry have been a growing concern, around 1.3 billion tons are leftover, which became an
environmental and financial issue [1]. Among these agro-waste stands out, food waste, halum and stems of
vegetables/fruits, grains and seeds, from which it is possible to obtain natural polymers [3]. Biopolymers
exhibit unique properties and can be produced from plants and crops wastes. Rubber, proteins, starch and
cellulose are some of the examples [4]. Cellulose has been used for the production of biopolymers,
nevertheless, because of the difficulty inherent in its extraction process, various methods have been studied
in order to optimize this process. Currently, cellulose derivatives are used, which is an example of cellulose
acetate, whose chemical purification process is quite costly and lengthy [1]. Thus, the present work, aims to
directly synthetize biopolymers from agro-wastes. Green chemistry methodology is applied to extract natural
polymers, such as cellulose, from vegetable wastes. Structural, morphological and mechanical
characterization of the produced materials are accessed and compared with conventional synthetic polymers.
Also, biodegradability assays will be performed to check the microorganisms’ capability to assimilate the
produced bioplastics
Information systems project management success
This paper aims to provide new insights into information systems (IS) project management success. Even though many studies found in the literature show results of software development projects, few studies address the success of IS (socio-technical) projects. Responses to an international survey, regarding 472 projects in total, showed that IS project management is achieving high levels of success; yet, only a minority of projects end without changes in scope, schedule or cost. Furthermore, the results show that changes in scope, schedule or cost are frequent in this kind of project and do not significantly affect the perception of success. These results provide researchers and practitioners with a better understanding of IS project management success evaluation.- (undefined
The example of the Quartzite from the "Upper Quartzite Formation", "Trás-os-Montes e Alto Douro" (NE Portugal). Its characterization as natural stone for construction
The example of the quartzite from the Upper Quartzite Formation, from Trás-os-Montes e Alto Douro (Northern Portugal); its characterization to use as natural stone
Comunicação apresentada em: "Global Stone Congress 2012", Borba, Portugal, 16-20 July, 201
Os "xistos" do Grupo do Douro como recurso geológico
Os xistos, nomeadamente os do Grupo do Douro, antigamente designado Complexo Xisto-Grauváquico, por serem pouco
deformados e de baixo grau de metamorfismo podem ter interesse económico por possuírem características geoquímicas e
físico-mecânicas que permitem o seu aproveitamento como rocha natural. Nesta contribuição, apresentamos os casos de Eucísia, Nozelos e Poio
Motivations for high performance teams of information systems projects
As equipas de elevado desempenho apresentam características únicas que as diferenciam das restantes, sendo um dos aspetos fundamentais a motivação dos seus elementos. Neste trabalho são apresentados os resultados parciais de um estudo de caso focado no elevado desempenho das equipas de projetos de sistemas de informação. Muito concretamente, identifica-se um conjunto de aspetos que contribuem para a motivação dos elementos de uma equipa, de acordo com a sua própria perspetiva. Este trabalho visa proporcionar uma melhor compreensão dos aspetos que influenciam a motivação dos elementos das equipas de elevado desempenho e, assim, contribuir para o estudo e prática da gestão de projetos de sistemas de informação.High performance teams present unique characteristics that make them distinct from the others,
being one of the fundamental aspects the motivation of its elements. In this paper are presented
the partial results of a case study focused on high performance teams of information systems
projects. Specifically, it is identified a set of aspects that contribute to the motivation of the
team’s elements, according to their own perspective. This work aims to provide a better
understanding of the aspects that influence the motivation of the elements for high performance
teams and thus contribute to the study and practice of information systems project management.This work has been supported by COMPETE: POCI-01-0145-FEDER-007043 and FCT – Fundação
para a Ciência e Tecnologia within the Project Scope: UID/CEC/00319/2013.info:eu-repo/semantics/publishedVersio
"Schist" from "Trás-os-Montes e Alto Douro" (NE Portugal) - Potential use as Natural Stone
Publicado em: "Key Engineering Materials", Vol. 548 (2013), p. 205-21
Cancer Models on Chip:Paving the Way to Large Scale Trial Applications
Cancer kills millions of individuals every year all over the world (Global Cancer Observatory). The physiological and biomechanical processes underlying the tumor are still poorly understood, hindering researchers from creating new, effective therapies. Inconsistent results of preclinical research, in vivo testing, and clinical trials decrease drug approval rates. Three-dimensional tumor-on-chip models integrate biomaterials, tissue engineering, fabrication of microarchitectures, and sensory and actuation systems in a single device, enabling reliable studies in fundamental oncology and pharmacology. This review includes a critical discussion about their ability to reproduce the tumor microenvironment, the advantages and drawbacks of existing tumor models and architectures, and major components and fabrication techniques. The focus is on current materials and micro/nanofabrication techniques used to manufacture reliable and reproducible microfluidic tumor-on-chip models for large-scale trial applications.</p
- …