Influence of CNC milling strategies on complex surface machining

Milling strategies are an integral part of CAD/CAM systems. Every CAD/CAM system offers unique strategies to differentiate itself from the competition. The article deals with analysis of CNC milling strategies in CAD/CAM system Edgecam 2017 R2. Analysis is divided into two parts. In first part are analysed roughing strategies with focus based on time necessary for removal of material. Second part is focused on finishing strategies and achieving the highest quality of surface. In conclusion, the article deals with the analysis of existing milling strategies and the creation of a database for the assignment of optimal roughing and finishing strategies for specified components

Użytkowanie systemu baz danych wykorzystujących protokół STEP

Information systems in today’s manufacturing enterprises are distributed. Data exchange and share can be performed by computer network systems. The present manufacturing scenario demands the efficient database systems for manufacturing to perform the operations globally. Database systems are the key to implementing information modeling. Engineering informations modeling requires database support. This paper proposes a manufacturing database system for STEP-NC data from EXPRESS entities.We współczesnych przedsiębiorstwach przemysłowych systemy informatyczne występują powszechnie i są niezbędne. Udostępnienie i wymiana danych odbywa się przy wykorzystaniu sieci komputerowych. Realizacja procesu wytwórczego wymaga wydajnych systemów produkcyjnych baz danych do wykonywania operacji w ujęciu globalnym. Systemy baz danych są kluczem do zarządzania przepływem informacji. Inżynieria zarządzania informacją wymaga odpowiednich metod obsługi bazy danych. Niniejszy artykuł proponuje produkcyjną bazę danych opartą na modelu STEP-NC korzystającą ze języka programowania EXPRESS

Rodzaje danych w języku EXPRESS

Defined data types are provided as part of the language. Every attribute, local variable or formal parameter has an associated data type. The core information modelling language consists of data types that determine its modelling capabilities. Based on the data types of traditional programming languages, language EXPRESS absorbing mechanisms used in object-oriented technologies, such as inheritance mechanism which is used to describe the production data, using a wide range of data types. This article dealt with the data types of EXPRESS language, and describe their basic options.Zdefiniowane typy danych są dostarczane jako część języka programowania. Każdy atrybut, zmienna lokalna lub parametr formalny ma skojarzony typ danych. Kod źródłowy języka programowania zawiera typy danych, które określają jego możliwości programowania. W oparciu o typy danych z tradycyjnych języków programowania, język EXPRESS wykorzystuje mechanizmy stosowane w technologiach programowania obiektowego, takie jak mechanizm dziedziczenia, który jest używany do opisu procesu produkcyjnego, przy użyciu szerokiego zakresu typów danych

Thermococcus kodakarensis Genetics: TK1827-Encoded β-Glycosidase, New Positive-Selection Protocol, and Targeted and Repetitive Deletion Technology▿ †

Inactivation of TK1761, the reporter gene established for Thermococcus kodakarensis, revealed the presence of a second β-glycosidase that we have identified as the product of TK1827. This enzyme (pTK1827) has been purified and shown to hydrolyze glucopyranoside but not mannopyranoside, have optimal activity at 95°C and from pH 8 to 9.5, and have a functional half-life of ∼7 min at 100°C. To generate a strain with both TK1761 and TK1827 deleted, a new selection/counterselection protocol has been developed, and the levels of β-glycosidase activity in T. kodakarensis strains with TK1761 and/or TK1827 deleted and with these genes expressed from heterologous promoters are described. Genetic tools and strains have been developed that extend the use of this selection/counterselection procedure to delete any nonessential gene from the T. kodakarensis chromosome. Using this technology, TK0149 was deleted to obtain an agmatine auxotroph that grows on nutrient-rich medium only when agmatine is added. Transformants can therefore be selected rapidly, and replicating plasmids can be maintained in this strain growing in rich medium by complementation of the TK0149 deletion

The impact of selected technological and material parameters on the strength of adhesive steel sheets joints

The following paper analyses selected problems regarding the impact of technological parameters and the type of adherend material on the strength of adhesive-bonded steel sheet joints. The subject of the test was a single-lap adhesive joint of S235JR steel sheet. Joints were formed on two types of substrates: with or without corrosion products on the surface. The surface of steel sheet adherends was pre-treated with three cleaning solutions: acetone, Wiko industrial degreasing agent and Cortanin F anti-corrosion agent, depending on the state of the surface. Adhesive joints were formed with Epidian 53/ET/100:15 epoxy adhesive. The formed joints were subjected to one of three ageing variants: 14 days, two months and 3 months, which were followed by destructive testing to determine the shear strength of joints. The analysis of results obtained in the tests indicates that the strength performance of adhesive joints of corrosion-free adherends was characterised by higher values than in corroded steel sheets, regardless of ageing time

Histones in Crenarchaea

Archaeal histone-encoding genes have been identified in marine Crenarchaea. The protein encoded by a representative of these genes, synthesized in vitro and expressed in Escherichia coli, binds DNA and forms complexes with properties typical of an archaeal histone. The discovery of histones in Crenarchaea supports the argument that histones evolved before the divergence of Archaea and Eukarya

Spontaneous trpY Mutants and Mutational Analysis of the TrpY Archaeal Transcription Regulator▿

Over 90% of Methanothermobacter thermautotrophicus mutants isolated as spontaneously resistant to 5-methyl tryptophan had mutations in trpY. Most were single-base-pair substitutions that identified separate DNA- and tryptophan-binding regions in TrpY. In vivo and in vitro studies revealed that DNA binding was sufficient for TrpY repression of trpY transcription but that TrpY must bind DNA and tryptophan to assemble a complex that represses trpEGCFBAD

Polarity in Archaeal Operon Transcription in Thermococcus kodakaraensis▿

An in vivo archaeal gene reporter system has been established based on TK1761, a gene that encodes a nonessential β-glycosidase in Thermococcus kodakaraensis. Following the introduction of nonsense codons into promoter-proximal genes, polarity in operon expression in this archaeon has been established by both microarray hybridization assays and a reporter gene expression system