Abstract The development of an original low-cost hardware/software apparatus to optically control the laser beam and measure quality parameters by image analysis using a monochrome matrix sensor is described, along with experimental validation. Laser parameters, namely beam waist, divergence, Rayleigh range and M2, which are the most relevant in manufacturing operations (like optical measurement and laser processing), have been physically and mathematically characterized. Strategies for the apparatus size reduction are also presented, including the use of a prism to reduce by half the optical path, and a camera model to simulate the sensor resolution.

With its ability to fabricate fully dense three-dimensional structures by selectively melting micro-sized metal powder, the additive manufacturing process of laser beam melting (LBM) is considered by many to be a significant technology that is complementary to the conventional forming and subtractive manufacturing processes. However, even with its ability to fabricate structures with characteristics comparable to conventional fabrication, the LBM process often lacks the consistency and degree of repeatability essential for its industrial acceptance for certain end-product applications. Inconsistency in the characteristics of structures is often related to a combination of variations in system technology, process, and user influence. In order to understand fully the potential and limitations of the LBM process, the paper discusses the design, methodology, and results of a round robin test conducted within the Collaborative Working Group (CWG) lasers in production at the International Academy of Production Engineering (CIRP). Observed mechanical characteristics for samples from each of the participants are presented. The experiments are designed to obtain data related to mechanical characteristics for different build orientations and processing conditions in addition to the inherent system technology variations. The paper further discusses the observed process phenomena and their association with the induced mechanical characteristics.

Die additiewe laserstraal smeltproses word deur kenners as 'n noemenswaardige tegnologie wat bydra tot die konvensionele vorming- en masjineringvervaardigingsprosesse geag, omdat dit oor die vermoë beskik om digte, driedimensionele strukture te vervaardig. Selfs met dié vermoë om strukture met eienskappe soortgelyk aan die konvensioneel vervaardigde strukture, ly die laserstraal smeltproses dikwels aan n tekort aan konsekwentheid en herhaalbaarheid wat krities is tot die industriële aanvaarding daarvan. Die veranderlikheid in die eienskappe van strukture is dikwels verwant aan 'n kombinasie van variasies in die sisteem tegnologie, proses- en gebruikerinvloed. Hierdie navorsing bespreek n rondomtalie toets wat op verskeie laserstraal smelters, wat by die Internasionale Akademie van Produksieingenieurs (CIRP) in gebruik is, uitgevoer is. Die toetse se mikpunt was om die potensiaal en beperkinge geassosieer met die laserstraal smeltproses beter te verstaan. Die waargeneemde meganiese eienskappe van monsters van elkeen van die monsters word voorgehou. Die eksperimente is ontwerp om data, wat verwant is aan die meganiese eienskappe wanneer verskeie veranderlikes tydens die vervaardigingsproses teenwoordig is, te verkry. Die waargeneemde prosesverskynsels en hul assosiasies met die geïnduseerde meganiese eienskappe, word dan bespreek.

Abstract Studies have shown that the supplementation of vegetable oils, in poly(3-hydroxybutyrate) production, provides an increase in the process productivity, besides inducing lipase activity in the medium. The supplementation with miniemulsified oils could potentialize these results. In this work, the influence of supplementation of the medium with soybean oil, without treatment and miniemulsified, on polymerr production was evaluated. The best moment to supplement the medium and its influence on lipase activity were also analyzed. The results showed that the supplementation with miniemulsified soybean oil promoted an increase of 9.7% in polymer content and the productivity increased from 0.58 to 0.63 g.L-1.h-1, when compared with the culture without supplementation. The best time to add the supplement is in the beginning of the production phase. The lipase activity was higher for the culture supplemented with miniemulsified soybean oil, promoting the use of the oil.

This work describes the calibration of a gas chromatograph equipped with a sulfur chemiluminescent detector with dual plasma (GC-SCD-DP) for analysis of sulfur-containing petroleum refinery gaseous streams. A packed column in an inert tube (Sulfinert) and an inlet system resistant to reactive sulfur compounds were used. The behavior of the calibration procedure over time depended on the sulfur compound: hydrogen sulfide (H2S), carbonyl sulfide (COS), methanethiol (MeSH) and dimethylsulfide (DMS) gave constant responses, whereas SO2 presented a systematic increase and dimethyldisulfide (DMDS) showed a systematic decrease of their response factors. In all cases, the response factors were lower than the ones found in the ASTM D 5504-08 method. The GC-SCD-DP technique proved to be a suitable tool for quantification of sulfur compounds (including SO2) at µg.m-3 levels in several petroleum refinery gaseous streams.

O monitoramento da ocorrência de plantas de capim-arroz resistentes ao herbicida quinclorac foi realizado no Rio Grande do Sul e em Santa Catarina, visando determinar a origem da resistência e sua disseminação, bem como detectar práticas de manejo ou condições edafoclimáticas provavelmente envolvidas na seleção e distribuição geográfica do biótipo resistente. As sementes foram coletadas, purificadas e homogeneizadas, sendo os estudos realizados em laboratório e casa de vegetação. Em laboratório, foi conduzido teste de germinação padrão, embebendo as sementes dos biótipos nas doses de 0x, 1x, 2x, 6x, 16x e 32x a concentração recomendada de quinclorac (375 g ha-1), sendo avaliadas a curva de germinação e a porcentagem de controle aos 14 dias após semeadura (DAS); em casa de vegetação, foram utilizadas as mesmas doses, aspergidas sobre as plantas aos 20 dias após a emergência (DAE), com as plantas no estádio de quatro folhas a um perfilho. Foram avaliadas a porcentagem de controle e a massa seca aos 35 DAE; biótipos com coeficiente de resistência (RI) superior a quatro foram considerados resistentes. Neste estudo foram encontradas sementes de capim-arroz resistentes ao herbicida quinclorac. Elaborou-se mapa de distribuição dos biótipos resistentes nas áreas amostradas dos Estados do Rio Grande do Sul e Santa Catarina. O herbicida profoxydim é alternativa de controle dos biótipos de capim-arroz resistentes a quinclorac.

The monitoring of Echinochloa sp. plants resistant to quinclorac was conducted in Rio Grande do Sul and Santa Catarina, Brazil to determine the origin of resistance and its dissemination, as well as to detect practices or climatic conditions related to the selection and geographic distribution of the resistant biotype. The seeds were collected, purified and standardized, and trials conducted under growth chamber and greenhouse conditions. In the growth chamber, a standard germination test was conducted with the seeds being submitted to rates of 0x, 1x, 2x, 6x, 16x and 32x and to the recommended rate of quinclorac, followed by germination curve and seedlings survival evaluation 14 days after sowing (DAS); the same herbicide rates were evaluated under greenhouse conditions, applied over the plants 20 days after emergence (DAE). Dry weight and control were evaluated 35 DAE, and biotypes with RI above four were considered resistant. A map of both states was elaborated where distribution of resistance to quinclorac was showed graphically, followed by herbicide profoxydim test as an alternative for the resistant biotype control.

Yeast multi-copy vectors carrying the formaldehyde-resistance marker gene SFA have proved to be a valuable tool for research on industrially used strains of Saccharomyces cerevisiae. The genetics of these strains is often poorly understood, and for various reasons it is not possible to simply subject these strains to protocols of genetic engineering that have been established for laboratory strains of S. cerevisiae. We tested our vectors and protocols using 10 randomly picked baker's and wine yeasts all of which could be transformed by a simple protocol with vectors conferring hyperresistance to formaldehyde. The application of formaldehyde as a selecting agent also offers the advantage of its biodegradation to CO2 during fermentation, i.e., the selecting agent will be consumed and therefore its removal during down-stream processing is not necessary. Thus, this vector provides an expression system which is simple to apply and inexpensive to use