Search

When using a new powder material in each individual selective laser melting unit, the process engineer has to conduct process development works (PDW) to find the optimal combination of process parameters. The results of the PDW are analysed manually by the process engineer without the use of process decision support tools. Due to the expanding technological capabilities of the equipment and the available range of material properties, the possible set of parameters is also expanding, complicating the already non-trivial process of searching for printing process parameters. In order to reduce the PDW time, in this paper we proposed a rapid analysis tool to select individual experimental results with single welded tracks of AlSi10Mg powder. The process of conducting the experiment on domestic equipment was reviewed and the efficiency of the automation tool was investigated in comparison with the traditional manual selection approach. It is concluded that it is possible to apply the developed tool for materials and installations of additive manufacturing not considered in the study.

Layered manufacturing (LM) technology has the capability to fabricate 3D physical models efficiently, overcoming the limitations of geometric complexities. However, the surface quality of LM-processed parts often falls short compared to parts made through traditional numerically controlled manufacturing technology. This issue of surface roughness has become a significant concern, despite the numerous potential advantages offered by LM. To address this, an elaborate methodology is proposed to predict the surface roughness of LM-processed parts. The proposed methodology takes into account both theoretical and real-world characteristics of surface roughness distributions to accurately reflect the actual roughness distributions in the predictions. This methodology was tested and used to evaluate properties of the H15N5D4B and KH28M6 materials. To achieve this, a design of the testing sample was developed, and a roughness distribution expression was introduced, utilizing measured roughness data from the aforementioned sample. This expression allows engineers to obtain surface roughness values for all surface angles, i.e., desired 3D models. The methodology also includes a prediction application, which demonstrates the validity and effectiveness of the proposed approach through several application examples.

On the basis of 20 years of research in Northeast Russia, issues concerning the validity, ecology, and zoogeography of N. tumidus van Cleave et Bangham, 1949 are discussed. This paper presents data on the infection of arctic chars of the genus Salvelinus by acanthocephalans in several mountain lakes of this region. Finds of N. tumidus in whitefish (Coregonidae) from lakes of other mountain regions of Southern and Western Siberia are described. Paleogeographic reconstructions of vast lake basins in Siberia are considered. These hypotheses give an idea of probable habitats of ancestral forms of salmonid fish which currently serve as obligatory definitive hosts of N. tumidus in their Asian range. Based on the available data on the ways of formation of isolated populations of arctic char and whitefish in continental mountain areas, it is suggested that the modern range of the acanthocephalan N. tumidus is related to the distribution of such fish populations in North Asia. Keywords: Acanthocephala, Neoechinorhynchus tumidus, arctic chars, coregonid fish, mountain lakes, Siberia, Northeast Russia. [ABSTRACT FROM AUTHOR]

Museums provide unique learning opportunities in soil science. The Bob Campbell Geology Museum in Clemson, SC, features an exhibit of minerals and rocks common in the state and in its geologic history. We developed a hands-on laboratory exercise utilizing an exhibit that gives college students an opportunity to visualize regional minerals and rocks from which regional soil parent materials are derived. Clemson University students from various majors had a field trip and a hands-on experience with the local minerals and rocks during FNR 204: Soil Information Systems course taught in the fall 2008, summer 2011, and fall 2011 (134 students total). Students were then asked to fill out a survey providing answers to 15 questions related to their learning experience. Sixty-six percent of the students had never visited a Geology Museum before this field trip and 40% of the students did not know about the Geology Museum's existence on campus. Ninety-three percent of the students thought the visit to the Geology Museum would be helpful with preparation for class quizzes and exams, and 92% of the students would recommend that their friends visit this museum in their free time. Overall, student responses to the questionnaire about their laboratory experience at the Geology Museum were positive. Laboratory exercises that are specifically designed to bridge university-level course material and museum collections produce learning synergy that is greater than either an independent museum visit or classroom instruction. (Contains 5 figures and 4 tables.)