HALOGEN-FREE FLAME-RETARDANT POWDER MATERIALS FOR LASER SINTERING: EVALUATION AND PROCESS STABILITY ANALYSIS

The high flammability of components manufactured by laser-based powder bed fusion of plastics (PBF-LB/P) using standard polyamide 12 (PA12) powder still severely restricts their use in industries such as electronics, aviation, and transportation. A key factor for the further establishment of PBF-LB/P is the expansion of the material portfolio with, for example, refreshable and halogen-free flame-retardant (FR) powder materials. Accordingly, various halogen-free FRs are investigated in this work and evaluated with respect to their use in PBF-LB/P. First, their decomposition behavior and mode of action are examined. Subsequently, the additives are dry blended with PA12 to investigate properties relevant for PBF-LB/P, such as particle morphology, thermal behavior, and melt viscosity. Afterwards, test specimens for UL94 vertical flame-retardancy tests are produced by processing the dry blends on an EOS P3 PBF-LB/P system. Finally, the process stability of the process-aged powder blends is investigated by again examining thermal behavior and melt viscosity.Mechanical Engineerin

Assessing the Impact of the Powder Production Method on Ceramic-filled Polyamide Composites made by Laser Sintering

Polymer composites represent the industry standard in injection molding for the production of plastic components with increased requirements in terms of heat resistance and stiffness. In the field of laser sintering (LS), these materials are less common so far. In order to extend the available material variety for the LS process, new ceramic-filled Polyamide 613 powders are investigated within the scope of this work. Here, the resulting properties from two different powder production methods are compared. One filled powder is produced by dry blending and the other powder with the same filler and filling ratio is produced by encapsulating the filler particles inside the polymer particles within the dissolution-precipitation process. It was found that encapsulating the filler particles can provide certain benefits for the processability, for example an improved powder flowability or better filler dispersion. However, encapsulating the filler also alters the thermal properties of the precipitated powder.Mechanical Engineerin

COMPETITION AMONG HOSPITALS AND ITS MEASUREMENT: THEORY AND A CASE STUDY

Our paper provides several insights on the characteristics of the concept of “Poles d’Excellence Rurale” (PER) through bilateral comparisons with that of Competitive Pole (CP) and cluster. The concept of PER is a French government’ initiative designed for the development of rural areas similar to that of the Competitive Pole. We emphasize important particularities of these concepts by analyzing some of their similarities and major differences.Pole d’Excellence Rurale, Competitive Pole, cluster, rural development

Comparative fish impingement at two adjacent water intakes on the mid-Columbia River

Fish impingement on the mid-Columbia River is a concern only from April through June, and is limited to a few species. A comparison of fish impingement was made from May through June 1977 at two water intake facilities located 276 m (900 ft) apart on the Columbia River at River Mile 380. The intakes each have a capacity of over 25 m/sup 3//s (891 cfs), are similarly designed, and have comparable water intake velocities. Collections from traveling screens at 100-N intake yielded 89 dead chinook salmon fry. During the same period 766 chinook salmon fry were collected at the Hanford Generating Project (HGP). These data represent an estimated impingement of 2695 chinook salmon fry, 97% of which survived. Impingement for other fish species was similar at both intakes, except that HGP impinged twice as many yellow perch fry as 100-N (2642 versus 1296). Several hypotheses are offered to explain the differences in impingement between intakes. These include subtle differences in forebay configuration, curtain wall location, and possible differences in fish behavioral responses to the intake facilities

Feiras livres como alternativa de comercialização de produtos da agrofloresta.

Com a busca por alternativas comerciais socialmente justas como maneira de otimizar a comercialização de produtos provenientes de agricultura familiar, destaca se a venda direta através de feiras, livres, que permite acesso direto ao consumidor sem necessidade de intermediadores. O Grupo de Produtores Agroflorestais Gralha Azul, de Morretes-PR, iniciou plantios de agroflorestas agroecológicas em 2009, sendo formado, atualmente, por 12 famílias de agricultores. Há um ano, o Gralha Azul iniciou sua participação na Matinfeira, feira semanal de produtos da agricultura familiar em Matinhos, PR. Com o objetivo de caracterização dos produtos, produtores e do processo de comercialização, foram acompanhados e sistematizados em planilha a comercialização destes produtos em 22 feiras semanais, entre maio e dezembro de 2012. Onze produtores participaram da Matinfeira, comercializando entre 13 e 29 variedades de alimentos, e proporcionando uma renda que variou de R$101,00 a R$ 386,50, por semana. Mensalmente, as feiras permitiram uma receita bruta de R$ 141,17 por produtor familiar agroflorestal. Apesar desse baixo valor, há que se considerar que o mesmo reflete os primeiros seis meses de atuação do Grupo no processo de comercialização na feira (Matinfeira). A venda direta através desta feira livre mostra potencial como alternativa comercial socialmente justa para os produtores em transição agroecológica do Grupo Gralha Azul

Preliminary survey of polychlorinated biphenyls (PCBs) in aquatic habitats and Great Blue Herons on the Hanford Site. [Ardea herodias]

Polychlorinated biphenyls (PCBs), constituents of insulating fluids used in electrical transformers and capacitors, were identified during a preliminary survey of waters, sediments, and fish from five locations on the Hanford Site in southeastern Washington State: Gable Mountain Pond, B Pond, West Pond, White Bluffs Slough on the Columbia River, and a pond on the Wahluke Slope. These aquatic areas are all within the foraging range of great blue herons (Ardea herodias) that nest on the Hanford Site. Of those waters that contained PCBs, concentrations were found to be somewhat over 1 ng/L, but less than 20 ng/L, and equal to or less than concentrations reported for other freshwater regions of the United States. The PCBs in sediments and fish closely resembled the chromatographic profile of Aroclor 1260, a commercial PCB mixture produced in the United States by the Monsanto Company. Concentrations of PCBs detected in the sediments were 10 to 100 times lower than those found in soils and sediments from other areas of the nation. Concentrations of PCBs in fat from Hanford great blue herons ranged from 3.6 to 10.6 ppM, while PCB concentrations in herons from other areas of the Pacific Northwest ranged from 0.6 to 15.6 ppM. Great blue herons at Hanford contained PCB isomer distributions closely matching that of Aroclor 1260; great blue herons from other locations contained isomer distributions indicating the presence of a mixture of aroclors. 21 refs., 13 figs., 8 tabs

Consanguinity and pregnancy outcomes in a multi-ethnic, metropolitan European population

Objective The aim of the present study was to assess the risk of major anomalies in the offspring of consanguineous couples, including data on the prenatal situation. Methods Over 20 years (1993–2012), 35 391 fetuses were examined by prenatal sonography. In 675 cases (1.9%), parents were consanguineous, with 307 couples (45.5%) related as first cousins, 368 couples (54.5%) beyond first cousins. Detailed information was retrieved on 31 710 (89.6%) fetuses, (consanguineous 568: 1.8%). Results Overall prevalence of major anomalies among fetuses with non-consanguineous parents was 2.9% (consanguineous, 10.9%; first cousins, 12.4%; beyond first cousins, 6.5%). Adjusting the overall numbers for cases having been referred because of a previous index case, the prevalences were 2.8% (non-consanguineous) and 6.1% (consanguineous) (first cousin, 8.5%; beyond first cousin, 3.9%). Further adjustment for differential rates of trisomic pregnancies indicated 2.0%/5.9% congenital anomalies (non-consanguineous/consanguineous groups), that is, a consanguinity-associated excess of 3.9%, 6.1% in first cousin progeny and 1.9% beyond first cousin. Conclusions The prevalence of major fetal anomalies associated with consanguinity is higher than in evaluations based only on postnatal life. It is important that this information is made available in genetic counselling programmes, especially in multi-ethnic and multi-religious communities, to enable couples to make informed decisions