Portugal has a great diversity of ecoclimatic areas and Sesimbra was chosen to carry out a study on WSP efficiencies over five years (1989 to 1993). According to Pina Manique & Albuquerque (1954), the climate is classified as Atlantic Mediterranean (AM). Some environmental and climatic parameters have been studied in order to define the area. The treatment system at Sesimbra has three ponds: anaerobic, facultative and maturation. The physical and chemical parameters studied in the WSP system were: Temperature, pH, Dissolved Oxygen, Conductivity, BOD5, COD, nitrates, nitrites, ammonia and total nitrogen, total and volatile suspended solids, total phosphorus and orthophosphates. Algal populations and the following microbiological parameters were studied: total and fecal coliforms, fecal Streptococci, Clostridium perfringens, Pseudomonas aeruginosa and some Enterobacteriaceae. The K and K20 kinetic parameters were studied and derived for the three ponds utilizing the seasonal regional characteristics from the surrounding area. These values were then correlated with temperature and the subsequent removal efficiencies for each pond deduced. The data obtained indicate a necessity to determine the seasonal fluctuations of the K and K20 kinetic parameters for the WSP systems.

This paper deals with the engineering aspects related to the rf energy coupling in Plasma Enhanced Chemical Vapour Deposition (PECVD) processes, in a diode-type unit in which an extra grid is used. The main emphasis is given in the determination of the real power delivered to the gas and comparing it with the total power losses, besides determining the best way to control the powder formed during the process. © 1994.

A [2Fe-2S] cluster has been detected in mammalian ferrochelatase, the terminal enzyme of the heme biosynthetic pathway. Natural ferrochelatase, purified from mouse livers, and recombinant ferrochelatase, purified from an overproducing strain of Escherichia coli, were investigated by electron paramagnetic resonance (EPR) and Mossbauer spectroscopy. In their reduced forms, both the natural and recombinant ferrochelatases exhibited an identical EPR signal with g values (g = 2.00, 1.93, and 1.90) and relaxation properties typical of [2Fe-2S](+) cluster. Mossbauer spectra of the recombinant ferrochelatase, purified from a strain of E. coli cells transformed with a plasmid encoding murine liver ferrochelatase and grown in Fe-57-enriched medium, demonstrated unambiguously that the cluster is a [2Fe-2S] cluster. No change in the cluster oxidation state was observed during catalysis, The putative protein binding site for the Fe-S cluster in mammalian ferrochelatases is absent from the sequences of the bacterial and yeast enzymes, suggesting a possible role of the [2Fe-2S] center in regulation of mammalian ferrochelatases.

The aim of this work is to interpret the role of the lateral leakage current on the a-Si:H solar cell performances (J-V characteristics, responsivity and the apparent device degradation behaviour), under low illumination conditions.

Silicon oxycarbide microcrystallinc layers, n- and p-doped, highly conductive and highly transparent have been produced using a Two Consecutive Decomposition and Deposition Chamber (TCDDC) system. The films exhibit suitable properties for optoelectronic applications where wide band gap materials with required conductivity and stability are needed. In this paper we present the role of partial oxygen pressure (po2) in controlling the composition, structure and transport properties (conductivity. δd and optical gap, Eop) of silicon oxycarbide microcrystalline layers. © 1994 Materials Research Society.

This paper presents results of the role of the oxygen partial pressure (pO2) used on the properties exhibited by doped μc silicon oxycarbide films produced by a Two Consecutive Decomposition and Deposition Chamber (TCDDC) system [1], where a spatial separation between the plasma and the growth regions is achieved. The films produced are highly conductive and transparent with suitable properties for optoelectronic applications.

In this paper is analyzed the work organization and the forms of quality control in a robotic welding station in a company of office equipment and metal components manufacturing. The robotic cell is recent and works in two shifts. Quality and production rationalization implied in this firms the adoption of a strategy of organization of teamwork, and it is supported the collaborative tools to decrease the possibilities for errors and to improve means and methods of manufacturing. The analysis of quality control process needed the use of productivity indicators. In this way it was possible to understand the connections between the function quality and the new form of work organization adopted in this innovative experience in Portugal.

A compact cesium ion source with a Wien filter is described. This source has been developed in order to produce a pure beam of cesium ions for positive SIMS analysis. The ions are produced by a surface ionization ion emitter. The initial beam is about 99% pure and the remaining 1% is removed via the Wien filter. An asymmetric einzel lens at the end provides the focusing of the beam on the target. A short description of the source is presented as well as the measured final beam characteristics.