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Sample records for cellular slime mold

  1. Ground Testing of the EMCS Seed Cassette for Biocompatibility with the Cellular Slime Mold, Dictyostelium Discoideum

    Science.gov (United States)

    Hanely, Julia C.; Reinsch, Sigrid; Myers, Zachary A.; Freeman, John; Steele, Marianne K.; Sun, Gwo-Shing; Heathcote, David G.

    2014-01-01

    The European Modular Cultivation System, EMCS, was developed by ESA for plant experiments. To expand the use of flight verified hardware for various model organisms, we performed ground experiments to determine whether ARC EMCS Seed Cassettes could be adapted for use with cellular slime mold for future space flight experiments. Dictyostelium is a cellular slime mold that can exist both as a single-celled independent organism and as a part of a multicellular colony which functions as a unit (pseudoplasmodium). Under certain stress conditions, individual amoebae will aggregate to form multicellular structures. Developmental pathways are very similar to those found in Eukaryotic organisms, making this a uniquely interesting organism for use in genetic studies. Dictyostelium has been used as a genetic model organism for prior space flight experiments. Due to the formation of spores that are resistant to unfavorable conditions such as desiccation, Dictyostelium is also a good candidate for use in the EMCS Seed Cassettes. The growth substratum in the cassettes is a gridded polyether sulfone (PES) membrane. A blotter beneath the PES membranes contains dried growth medium. The goals of this study were to (1) verify that Dictyostelium are capable of normal growth and development on PES membranes, (2) develop a method for dehydration of Dictyostelium spores with successful recovery and development after rehydration, and (3) successful mock rehydration experiments in cassettes. Our results show normal developmental progression in two strains of Dictyostelium discoideum on PES membranes with a bacterial food source. We have successfully performed a mock rehydration of spores with developmental progression from aggregation to slug formation, and production of morphologically normal spores within 9 days of rehydration. Our results indicate that experiments on the ISS using the slime mold, Dictyostelium discoideum could potentially be performed in the flight verified hardware of

  2. Route 20, Autobahn 7, and Slime Mold: Approximating the Longest Roads in USA and Germany With Slime Mold on 3-D Terrains.

    Science.gov (United States)

    Adamatzky, Andrew I

    2014-01-01

    A cellular slime mould Physarum polycephalum is a monstrously large single cell visible by an unaided eye. The slime mold explores space in parallel, is guided by gradients of chemoattractants, and propagates toward sources of nutrients along nearly shortest paths. The slime mold is a living prototype of amorphous biological computers and robotic devices capable of solving a range of tasks of graph optimization and computational geometry. When presented with a distribution of nutrients, the slime mold spans the sources of nutrients with a network of protoplasmic tubes. This protoplasmic network matches a network of major transport routes of a country when configuration of major urban areas is represented by nutrients. A transport route connecting two cities should ideally be a shortest path, and this is usually the case in computer simulations and laboratory experiments with flat substrates. What searching strategies does the slime mold adopt when exploring 3-D terrains? How are optimal and transport routes approximated by protoplasmic tubes? Do the routes built by the slime mold on 3-D terrain match real-world transport routes? To answer these questions, we conducted pioneer laboratory experiments with Nylon terrains of USA and Germany. We used the slime mold to approximate route 20, the longest road in USA, and autobahn 7, the longest national motorway in Europe. We found that slime mold builds longer transport routes on 3-D terrains, compared to flat substrates yet sufficiently approximates man-made transport routes studied. We demonstrate that nutrients placed in destination sites affect performance of slime mold, and show how the mold navigates around elevations. In cellular automaton models of the slime mold, we have shown variability of the protoplasmic routes might depends on physiological states of the slime mold. Results presented will contribute toward development of novel algorithms for sensorial fusion, information processing, and decision making, and

  3. Star Mapping with Slime Mold Physarum Polycephalum

    Science.gov (United States)

    Mihklepp, M.; Domnitch, E.; Gelfand, D.; Foing, B. H.; van der Heide, E.

    2014-04-01

    Human curiosity and exploration towards outer space has led to many fantastic inventions and given way to alternative scenarios about the origins of life. In the Space Science in the Arts course together with ESTEC with support from ILEWG. I got interested about unicellular slime mold Physarum polycephalum. There has been and still is a lot of research on Physarum polycephalum. This brainless eucaryotic microbe has its smartness and external memory strategies. Physarum can navigate through a maze made of agar using the shortest route possible when two pieces of food are placed at two separate exits of the maze. It can build efficient networks - Physarum created network similar to the existing Tokyo train system. It is being used to control a robot, in USB-sensor and in sound synthesis. Right now there is a lot of research about using Physarum in bio-computing.

  4. Cellular automaton model of crowd evacuation inspired by slime mould

    Science.gov (United States)

    Kalogeiton, V. S.; Papadopoulos, D. P.; Georgilas, I. P.; Sirakoulis, G. Ch.; Adamatzky, A. I.

    2015-04-01

    In all the living organisms, the self-preservation behaviour is almost universal. Even the most simple of living organisms, like slime mould, is typically under intense selective pressure to evolve a response to ensure their evolution and safety in the best possible way. On the other hand, evacuation of a place can be easily characterized as one of the most stressful situations for the individuals taking part on it. Taking inspiration from the slime mould behaviour, we are introducing a computational bio-inspired model crowd evacuation model. Cellular Automata (CA) were selected as a fully parallel advanced computation tool able to mimic the Physarum's behaviour. In particular, the proposed CA model takes into account while mimicking the Physarum foraging process, the food diffusion, the organism's growth, the creation of tubes for each organism, the selection of optimum tube for each human in correspondence to the crowd evacuation under study and finally, the movement of all humans at each time step towards near exit. To test the model's efficiency and robustness, several simulation scenarios were proposed both in virtual and real-life indoor environments (namely, the first floor of office building B of the Department of Electrical and Computer Engineering of Democritus University of Thrace). The proposed model is further evaluated in a purely quantitative way by comparing the simulation results with the corresponding ones from the bibliography taken by real data. The examined fundamental diagrams of velocity-density and flow-density are found in full agreement with many of the already published corresponding results proving the adequacy, the fitness and the resulting dynamics of the model. Finally, several real Physarum experiments were conducted in an archetype of the aforementioned real-life environment proving at last that the proposed model succeeded in reproducing sufficiently the Physarum's recorded behaviour derived from observation of the aforementioned

  5. Theoretical approach to the effects of extremely low freqency electromagnetic fiels on Physarum polycephalum. [Slime molds

    Energy Technology Data Exchange (ETDEWEB)

    Wayland, J.R.

    1977-03-01

    Absolute reaction rate theory is applied to explain the increased time between successive synchronous mitotic division of the slime mold Physarum polycephalum when exposed to extremely low frequency electromagnetic fields. By ignoring the transition period from the normal (control) mitotic cycle to the lengthened mitotic cycle of exposed P. polycephalum, the change in the activation energy is established. This activation energy is in the range of enzyme-catalyzed reactions. The influence of changing frequency on the above transition period is considered to complete the model.

  6. Experimental Verification of Fully Decentralized Control Inspired by Plasmodium of True Slime Mold

    Science.gov (United States)

    Umedachi, Takuya; Takeda, Koichi; Nakagaki, Toshiyuki; Kobayashi, Ryo; Ishiguro, Akio

    This paper presents a fully decentralized control inspired by plasmodium of true slime mold and its validity using a soft-bodied amoeboid robot. The notable features of this paper are twofold: (1) the robot has truly soft and deformable body stemming from real-time tunable springs and a balloon, the former is utilized as an outer skin of the body and the latter serves as protoplasm; and (2) a fully decentralized control using coupled oscillators with completely local sensory feedback mechanism is realized by exploiting the long-distance physical interaction between the body parts induced by the law of conservation of protoplasmic mass. Experimental results show that this robot exhibits truly supple locomotion without relying on any hierarchical structure. The results obtained are expected to shed new light on design scheme for autonomous decentralized control system.

  7. Maternal inheritance of mitochondria: multipolarity, multiallelism and hierarchical transmission of mitochondrial DNA in the true slime mold Physarum polycephalum.

    Science.gov (United States)

    Moriyama, Yohsuke; Kawano, Shigeyuki

    2010-03-01

    Direct evidence of digestion of paternal mitochondrial DNA (mtDNA) has been found in the true slime mold Physarum polycephalum. This is the first report on the selective digestion of mtDNA inside the zygote, and is striking evidence for the mechanism of maternal inheritance of mitochondria. Moreover, two mitochondrial nuclease activities were detected in this organism as-candidates for the nucleases responsible for selective digestion of mtDNA. In the true slime mold, there is an additional-feature of the uniparental inheritance of mitochondria.Although mitochondria are believed to be inherited from the maternal lineage in nearly all eukaryotes, the mating types of the true slime mold P. polycephalum is not restricted to two: there are three mating loci--matA, matB,and matC--and these loci have 16, 15, and 3 alleles,-respectively. Interestingly, the transmission patterns of mtDNA are determined by the matA locus, in a hierarchical-fashion (matA hierarchy) as follows: matA7[matA2[matA11[matA12[matA15/matA16[matA1[matA6.The strain possessing the higher status of matA would be the mtDNA donor in crosses. Furthermore, we have found that some crosses showed biparental inheritance of mitochondria.This review describes the phenomenon of hierarchical transmission of mtDNA in true slime molds, and discusses the presumed molecular mechanism of maternal and biparental inheritance.

  8. Weight loss by Ppc-1, a novel small molecule mitochondrial uncoupler derived from slime mold.

    Directory of Open Access Journals (Sweden)

    Toshiyuki Suzuki

    Full Text Available Mitochondria play a key role in diverse processes including ATP synthesis and apoptosis. Mitochondrial function can be studied using inhibitors of respiration, and new agents are valuable for discovering novel mechanisms involved in mitochondrial regulation. Here, we screened small molecules derived from slime molds and other microorganisms for their effects on mitochondrial oxygen consumption. We identified Ppc-1 as a novel molecule which stimulates oxygen consumption without adverse effects on ATP production. The kinetic behavior of Ppc-1 suggests its function as a mitochondrial uncoupler. Serial administration of Ppc-1 into mice suppressed weight gain with no abnormal effects on liver or kidney tissues, and no evidence of tumor formation. Serum fatty acid levels were significantly elevated in mice treated with Ppc-1, while body fat content remained low. After a single administration, Ppc-1 distributes into various tissues of individual animals at low levels. Ppc-1 stimulates adipocytes in culture to release fatty acids, which might explain the elevated serum fatty acids in Ppc-1-treated mice. The results suggest that Ppc-1 is a unique mitochondrial regulator which will be a valuable tool for mitochondrial research as well as the development of new drugs to treat obesity.

  9. Evolving Transport Networks With Cellular Automata Models Inspired by Slime Mould.

    Science.gov (United States)

    Tsompanas, Michail-Antisthenis I; Sirakoulis, Georgios Ch; Adamatzky, Andrew I

    2015-09-01

    Man-made transport networks and their design are closely related to the shortest path problem and considered amongst the most debated problems of computational intelligence. Apart from using conventional or bio-inspired computer algorithms, many researchers tried to solve this kind of problem using biological computing substrates, gas-discharge solvers, prototypes of a mobile droplet, and hot ice computers. In this aspect, another example of biological computer is the plasmodium of acellular slime mould Physarum polycephalum (P. polycephalum), which is a large single cell visible by an unaided eye and has been proven as a reliable living substrate for implementing biological computing devices for computational geometry, graph-theoretical problems, and optimization and imitation of transport networks. Although P. polycephalum is easy to experiment with, computing devices built with the living slime mould are extremely slow; it takes slime mould days to execute a computation. Consequently, mapping key computing mechanisms of the slime mould onto silicon would allow us to produce efficient bio-inspired computing devices to tackle with hard to solve computational intelligence problems like the aforementioned. Toward this direction, a cellular automaton (CA)-based, Physarum-inspired, network designing model is proposed. This novel CA-based model is inspired by the propagating strategy, the formation of tubular networks, and the computing abilities of the plasmodium of P. polycephalum. The results delivered by the CA model demonstrate a good match with several previously published results of experimental laboratory studies on imitation of man-made transport networks with P. polycephalum. Consequently, the proposed CA model can be used as a virtual, easy-to-access, and biomimicking laboratory emulator that will economize large time periods needed for biological experiments while producing networks almost identical to the tubular networks of the real-slime mould.

  10. EFFECTIVENESS OF CELLULAR INJECTION MOLDING PROCESS

    Directory of Open Access Journals (Sweden)

    Tomasz Garbacz

    2013-06-01

    Full Text Available In a study of cellular injection, molding process uses polyvinylchloride PVC. Polymers modified with introducing blowing agents into them in the Laboratory of the Department of Technologies and Materiase of Technical University of Kosice. For technological reasons, blowing agents have a form of granules. In the experiment, the content of the blowing agent (0–2,0 % by mass fed into the processed polymer was adopted as a variable factor. In the studies presented in the article, the chemical blowing agents occurring in the granulated form with a diameter of 1.2 to 1.4 mm were used. The view of the technological line for cellular injection molding and injection mold cavity with injection moldings are shown in Figure 1. The results of the determination of selected properties of injection molded parts for various polymeric materials, obtained with different content of blowing agents, are shown in Figures 4-7. Microscopic examination of cross-sectional structure of the moldings were obtained using the author's position image analysis of porous structure. Based on analysis of photographs taken (Figures 7, 8, 9 it was found that the coating containing 1.0% of blowing agents is a clearly visible solid outer layer and uniform distribution of pores and their sizes are similar.

  11. Eumycetozoa = Amoebozoa?: SSUrDNA phylogeny of protosteloid slime molds and its significance for the amoebozoan supergroup.

    Directory of Open Access Journals (Sweden)

    Lora L Shadwick

    Full Text Available Amoebae that make fruiting bodies consisting of a stalk and spores and classified as closely related to the myxogastrids have classically been placed in the taxon Eumycetozoa. Traditionally, there are three groups comprising Eumycetozoa: myxogastrids, dictyostelids, and the so-called protostelids. Dictyostelids and myxogastrids both make multicellular fruiting bodies that may contain hundreds of spores. Protostelids are those amoebae that make simple fruiting bodies consisting of a stalk and one or a few spores. Protostelid-like organisms have been suggested as the progenitors of the myxogastrids and dictyostelids, and they have been used to formulate hypotheses on the evolution of fruiting within the group. Molecular phylogenies have been published for both myxogastrids and dictyostelids, but little molecular phylogenetic work has been done on the protostelids. Here we provide phylogenetic trees based on the small subunit ribosomal RNA gene (SSU that include 21 protostelids along with publicly available sequences from a wide variety of amoebae and other eukaryotes. SSU trees recover seven well supported clades that contain protostelids but do not appear to be specifically related to one another and are often interspersed among established groups of amoebae that have never been reported to fruit. In fact, we show that at least two taxa unambiguously belong to amoebozoan lineages where fruiting has never been reported. These analyses indicate that we can reject a monophyletic Eumycetozoa, s.l. For this reason, we will hereafter refer to those slime molds with simple fruiting as protosteloid amoebae and/or protosteloid slime molds, not as protostelids. These results add to our understanding of amoebozoan biodiversity, and demonstrate that the paradigms for understanding both nonfruiting and sporulating amoebae must be integrated. Finally, we suggest strategies for future research on protosteloid amoebae and nonfruiting amoebae, and discuss the

  12. The TOM Complex of Amoebozoans: the Cases of the Amoeba Acanthamoeba castellanii and the Slime Mold Dictyostelium discoideum.

    Science.gov (United States)

    Wojtkowska, Małgorzata; Buczek, Dorota; Stobienia, Olgierd; Karachitos, Andonis; Antoniewicz, Monika; Slocinska, Małgorzata; Makałowski, Wojciech; Kmita, Hanna

    2015-07-01

    Protein import into mitochondria requires a wide variety of proteins, forming complexes in both mitochondrial membranes. The TOM complex (translocase of the outer membrane) is responsible for decoding of targeting signals, translocation of imported proteins across or into the outer membrane, and their subsequent sorting. Thus the TOM complex is regarded as the main gate into mitochondria for imported proteins. Available data indicate that mitochondria of representative organisms from across the major phylogenetic lineages of eukaryotes differ in subunit organization of the TOM complex. The subunit organization of the TOM complex in the Amoebozoa is still elusive, so we decided to investigate its organization in the soil amoeba Acanthamoeba castellanii and the slime mold Dictyostelium discoideum. They represent two major subclades of the Amoebozoa: the Lobosa and Conosa, respectively. Our results confirm the presence of Tom70, Tom40 and Tom7 in the A. castellanii and D. discoideum TOM complex, while the presence of Tom22 and Tom20 is less supported. Interestingly, the Tom proteins display the highest similarity to Opisthokonta cognate proteins, with the exception of Tom40. Thus representatives of two major subclades of the Amoebozoa appear to be similar in organization of the TOM complex, despite differences in their lifestyle.

  13. Analysis of Rheb in the cellular slime mold Dictyostelium discoideum: Cellular localization, spatial expression and overexpression

    Indian Academy of Sciences (India)

    Pynskhem Bok Swer; Pooja Bhadoriya; Shweta Saran

    2014-03-01

    Dictyostelium discoideum encodes a single Rheb protein showing sequence similarity to human homologues of Rheb. The DdRheb protein shares 52% identity and 100% similarity with the human Rheb1 protein. Fluorescence of Rheb yellow fluorescent protein fusion was detected in the D. discoideum cytoplasm. Reverse transcription-polymerase chain reaction and whole-mount in situ hybridization analyses showed that rheb is expressed at all stages of development and in prestalk cells in the multicellular structures developed. When the expression of rheb as a fusion with lacZ was driven under its own promoter, the -galactosidase activity was seen in the prestalk cells. D. discoideum overexpressing Rheb shows an increase in the size of the cell. Treatment of the overexpressing Rheb cells with rapamycin confirms its involvement in the TOR signalling pathway.

  14. A fluid-filled soft robot that exhibits spontaneous switching among versatile spatiotemporal oscillatory patterns inspired by the true slime mold.

    Science.gov (United States)

    Umedachi, Takuya; Idei, Ryo; Ito, Kentaro; Ishiguro, Akio

    2013-01-01

    Behavioral diversity is an essential feature of living systems, enabling them to exhibit adaptive behavior in hostile and dynamically changing environments. However, traditional engineering approaches strive to avoid, or suppress, the behavioral diversity in artificial systems to achieve high performance in specific environments for given tasks. The goals of this research include understanding how living systems exhibit behavioral diversity and using these findings to build lifelike robots that exhibit truly adaptive behaviors. To this end, we have focused on one of the most primitive forms of intelligence concerning behavioral diversity, namely, a plasmodium of true slime mold. The plasmodium is a large amoeba-like unicellular organism that does not possess any nervous system or specialized organs. However, it exhibits versatile spatiotemporal oscillatory patterns and switches spontaneously between these. Inspired by the plasmodium, we built a mathematical model that exhibits versatile oscillatory patterns and spontaneously transitions between these patterns. This model demonstrates that, in contrast to coupled nonlinear oscillators with a well-designed complex diffusion network, physically interacting mechanosensory oscillators are capable of generating versatile oscillatory patterns without changing any parameters. Thus, the results are expected to shed new light on the design scheme for lifelike robots that exhibit amazingly versatile and adaptive behaviors.

  15. Cell Communication during Aggregation and Development of the Cellular Slime Mould Distyostelium discoideum.

    Science.gov (United States)

    1985-01-01

    assistance, and love. With special feelings, I thank my beautiful daughters, Jennifer and Renata, for their many hugs and words of encouragement during times...cellularly throughout development (Bonner et al., 1969; Malkinson and Ashworth , 1972) and it has been suggested that cAMP may induce cells to enter...Axenic Liquid Media (Watts and Ashworth , 1970) Oxoid Bacteriological Peptone 14.3g Oxoid Yeast Extract 7.15g D-Glucose 15.4g Na .12H 20 1.28g KHt2P:O4

  16. Slime mould flora of the Ślęża massif

    Directory of Open Access Journals (Sweden)

    Wanda Stojanowska

    2014-11-01

    Full Text Available In four succeding years 1971-1974 field investigation on the Myxomycetes of Ślęża massif has been carried out. Up to the present only 4 species of slime molds from this region were known. My last investigations give 63 new species and 4 new varieties to slime molds flora of Ślęża massif, and 5 new species to Silesia slime mold flora.

  17. Mold

    Centers for Disease Control (CDC) Podcasts

    2011-05-02

    This podcast answers a listener's question about the risks associated with mold after a natural disaster or severe weather.  Created: 5/2/2011 by National Center for Environmental Health (NCEH).   Date Released: 5/2/2011.

  18. On creativity of slime mould

    Science.gov (United States)

    Adamatzky, Andrew; Armstrong, Rachel; Jones, Jeff; Gunji, Yukio-Pegio

    2013-07-01

    Slime mould Physarum polycephalum is large single cell with intriguingly smart behaviour. The slime mould shows outstanding abilities to adapt its protoplasmic network to varying environmental conditions. The slime mould can solve tasks of computational geometry, image processing, logics and arithmetics when data are represented by configurations of attractants and repellents. We attempt to map behavioural patterns of slime onto the cognitive control vs. schizotypy spectrum phase space and thus interpret slime mould's activity in terms of creativity.

  19. Slime production by Staphylococcus saprophyticus.

    OpenAIRE

    Hjelm, E.; Lundell-Etherden, I

    1991-01-01

    Only 9 of 30 Staphylococcus saprophyticus strains produced slime in trypticase soy broth, while all did so in urine. It was found that urea was essential for the production of slime. The pH, the iron concentration, or the presence of sex hormones did not affect slime production.

  20. Sounds Synthesis with Slime Mould of Physarum Polycephalum

    Institute of Scientific and Technical Information of China (English)

    Eduardo R. Miranda; Andrew Adamatzky; Jeff Jones

    2011-01-01

    This paper introduces a novel application of bionic engineering: a bionic musical instrument using Physarum polycephalum. Physarum polycephalum is a huge single cell with thousands of nuclei, which behaves like a giant amoeba. During its foraging behavior this plasmodium produces electrical activity corresponding to different physiological states. We developed a method to render sounds from such electrical activity and thus represent spatio-temporal behavior of slime mould in a form apprehended auditorily. The electrical activity is captured by various electrodes placed on a Petri dish containing the cultured slime mold. Sounds are synthesized by a bank of parallel sinusoidal oscillators connected to the electrodes. Each electrode is responsible for one partial of the spectrum of the resulting sound. The behavior of the slime mould can be controlled to produce different timbres.

  1. Profile extrusion of wood plastic cellular composites and formulation evaluation using compression molding

    Science.gov (United States)

    Islam, Mohammad Rubyet

    Wood Plastic Composites (WPCs) have experienced a healthy growth during the last decade. However, improvement in properties is necessary to increase their utility for structural applications. The toughness of WPCs can be improved by creating a fine cellular structure while reducing the density. Extrusion processing is one of the most economical methods for profile formation. For our study, rectangular profiles were extruded using a twin-screw extrusion system with different grades of HDPE and with varying wood fibre and lubricant contents together with maleated polyethylene (MAPE) coupling agent to investigate their effects on WPC processing and mechanical properties. Work has been done to redesign the extrusion system setup to achieve smoother and stronger profiles. A guiding shaper, submerged in the water, has been designed to guide the material directly through water immediately after exiting the die; instead of passing it through a water cooled vacuum calibrator and then through water. In this way a skin was formed quickly that facilitated the production of smoother profiles. Later on chemical blowing agent (CBA) was used to generate cellular structure in the profile by the same extrusion system. CBA contents die temperatures, drawdown ratios (DDR) and wood fibre contents (WF) were varied for optimization of mechanical properties and morphology. Cell morphology and fibre alignment was characterized by a scanning electron microscope (SEM). A new compression molding system was developed to help in quick evaluation of different material formulations. This system forces the materials to flow in one direction to achieve higher net alignment of fibres during sample preparation, which is the case during profile extrusion. Operation parameters were optimized and improvements in WPC properties were observed compared to samples prepared by conventional hot press and profile extrusion.

  2. Trans-Canada Slimeways: Slime mould imitates the Canadian transport network

    CERN Document Server

    Adamatzky, Andrew

    2011-01-01

    Slime mould Physarum polycephalum builds up sophisticated networks to transport nutrients between distant part of its extended body. The slime mould's protoplasmic network is optimised for maximum coverage of nutrients yet minimum energy spent on transportation of the intra-cellular material. In laboratory experiments with P. polycephalum we represent Canadian major urban areas with rolled oats and inoculated slime mould in the Toronto area. The plasmodium spans the urban areas with its network of protoplasmic tubes. We uncover similarities and differences between the protoplasmic network and the Canadian national highway network, analyse the networks in terms of proximity graphs and evaluate slime mould's network response to contamination.

  3. Hydrogel Beads: The New Slime Lab?

    Science.gov (United States)

    Brockway, Debra; Libera, Matthew; Welner, Heidi

    2011-01-01

    Creating slime fascinates students. Unfortunately, though intrigue is at its peak, the educational aspect of this activity is often minimal. This article describes a chemistry lab that closely relates to the slime lab and allows high school students to explore the concepts of chemical bonding, properties, and replacement reactions. It involves the…

  4. Achene slime content in some taxa of Matricaria L. (Asteraceae)

    OpenAIRE

    Inceer, Huseyin

    2011-01-01

    The achenes of Matricaria aurea and two varieties of M. chamomilla (var. chamomilla and var. recutita) have slime cells on the surface and they are characterized by slime envelope formation during hydration. The slime in these taxa is composed of pectins and cellulose. The slime could play important role in the distribution and colonisation of new habitats in Matricaria taxa.

  5. Mold Allergy

    Science.gov (United States)

    ... Ask the Allergist Health Professionals Partners Media Donate Allergies Mold Allergy What Is a Mold Allergy? If you have an allergy that occurs over ... basement. What Are the Symptoms of a Mold Allergy? The symptoms of mold allergy are very similar ...

  6. Study on selenium extraction from anode slime

    Institute of Scientific and Technical Information of China (English)

    GU; Heng

    2005-01-01

    Taking a copper anode slime as the raw material, a novel process for selenium extraction was studied. The primary selenium recovery can reach above 88.5 % and the quality index of selenium product can be up to 99.5 %. The economic benefit resulted is remarkable and environment has been protected.

  7. Two HAP2-GCS1 homologs responsible for gamete interactions in the cellular slime mold with multiple mating types: Implication for common mechanisms of sexual reproduction shared by plants and protozoa and for male-female differentiation.

    Science.gov (United States)

    Okamoto, Marina; Yamada, Lixy; Fujisaki, Yukie; Bloomfield, Gareth; Yoshida, Kentaro; Kuwayama, Hidekazu; Sawada, Hitoshi; Mori, Toshiyuki; Urushihara, Hideko

    2016-07-01

    Fertilization is a central event in sexual reproduction, and understanding its molecular mechanisms has both basic and applicative biological importance. Recent studies have uncovered the molecules that mediate this process in a variety of organisms, making it intriguing to consider conservation and evolution of the mechanisms of sexual reproduction across phyla. The social amoeba Dictyostelium discoideum undergoes sexual maturation and forms gametes under dark and humid conditions. It exhibits three mating types, type-I, -II, and -III, for the heterothallic mating system. Based on proteome analyses of the gamete membranes, we detected expression of two homologs of the plant fertilization protein HAP2-GCS1. When their coding genes were disrupted in type-I and type-II strains, sexual potency was completely lost, whereas disruption in the type-III strain did not affect mating behavior, suggesting that the latter acts as female in complex organisms. Our results demonstrate the highly conserved function of HAP2-GCS1 in gamete interactions and suggest the presence of additional allo-recognition mechanisms in D. discoideum gametes.

  8. Magnetic seeding sedimentation (MSS) of coal slimes

    Science.gov (United States)

    Wu, Xiqing; Yue, Tao; Dai, Liang

    2017-01-01

    Magnetic seeding sedimentation (MSS), i.e. adding magnetic seeds and pre-magnetization for sedimentation, is a technique especially for sedimentation of fine slimes, improving the sedimentation performance by introducing the magnetic interactions between particles in a suspension and enlarging the apparent size of the fine particles. The fine coal slimes with a size of 66.68%-38μm were investigated by the MSS. Sedimentation tests were conducted, and some measurements, such as laser size analysis, magnetic susceptibility by vibrating sample magnetometer (VSM), were also applied in order to probe the mechanism of the MSS. Based on the tests, measurements and calculations it was demonstrated that the sedimentation of coal slimes increased with the additions of the magnetic seeds, and in the presence of the polyacrylamide, and also there appeared a relatively large apparent size of slimes after additions of magnetic seeds and/or polyacrylamide. So, the reason for the influence of MSS lies in fact that the presence of the polyacrylamide intensified the adsorption of magnetic seeds on the coal particles and the coverage of the magnetic seeds on the coal surface from 0.2% wt. to1.3% wt., resulting in increased magnetic susceptibility of coal particles from 9.13×10-9m3/kg to 22.17×10-9m3/kg and thus a low magnetic field strength of pre-magnetization needed for the magnetic agglomeration to happen among the coal particles (the threshold of magnetic field strength for agglomeration) from 602mT to 24mT prior to proper sedimentation.

  9. Advances in Physarum machines sensing and computing with Slime mould

    CERN Document Server

    2016-01-01

    This book is devoted to Slime mould Physarum polycephalum, which is a large single cell capable for distributed sensing, concurrent information processing, parallel computation and decentralized actuation. The ease of culturing and experimenting with Physarum makes this slime mould an ideal substrate for real-world implementations of unconventional sensing and computing devices The book is a treatise of theoretical and experimental laboratory studies on sensing and computing properties of slime mould, and on the development of mathematical and logical theories of Physarum behavior. It is shown how to make logical gates and circuits, electronic devices (memristors, diodes, transistors, wires, chemical and tactile sensors) with the slime mould. The book demonstrates how to modify properties of Physarum computing circuits with functional nano-particles and polymers, to interface the slime mould with field-programmable arrays, and to use Physarum as a controller of microbial fuel cells. A unique multi-agent model...

  10. Slime thickness evaluation of bored piles by electrical resistivity probe

    Science.gov (United States)

    Chun, Ok-Hyun; Yoon, Hyung-Koo; Park, Min-Chul; Lee, Jong-Sub

    2014-09-01

    The bottoms of bored piles are generally stacked with soil particles, both while boreholes are being drilled, and afterward. The stacked soils are called slime, and when loads are applied on the pile, increase the pile settlement. Thus to guarantee the end bearing capacity of bored piles, the slime thickness should be precisely detected. The objective of this study is to suggest a new method for evaluating the slime thickness, using temperature compensated electrical resistivity. Laboratory studies are performed in advance, to estimate and compare the resolution of the electrical resistivity probe (ERP) and time domain reflectometry (TDR). The electrical properties of the ERP and TDR are measured using coaxial type electrodes and parallel type two-wire electrodes, respectively. Penetration tests, conducted in the fully saturated sand-clay mixtures, demonstrate that the ERP produces a better resolution of layer detection than TDR. Thus, field application tests using the ERP with a diameter of 35.7 mm are conducted for the investigation of slime thickness in large diameter bored piles. Field tests show that the slime layers are clearly identified by the ERP: the electrical resistivity dramatically increases at the interface between the slurry and slime layer. The electrical resistivity in the slurry layer inversely correlates with the amount of circulated water. This study suggests that the new electrical resistivity method may be a useful method for the investigation of the slime thickness in bored piles.

  11. Allergies, asthma, and molds

    Science.gov (United States)

    Reactive airway - mold; Bronchial asthma - mold; Triggers - mold; Allergic rhinitis - pollen ... Things that make allergies or asthma worse are called triggers. Mold is a common trigger. When your asthma or allergies become worse due to mold, you are ...

  12. Anodic slimes formation in copper electrowinning

    Directory of Open Access Journals (Sweden)

    Ipinza, J.

    2004-02-01

    Full Text Available The slime formation in acidic electrolytes of copper with several metallic impurities has been studied. On Pb-Ca-Sn anode surface firstly the formation of PbSO4 takes place, then, it is transformed in PbO2, which covers the anode surface. It was experimentally established the formation of a manganese dioxide double layer at the anode. This layer was always composed of a thick external layer of non-adhering and easily removable scales, and of a thin internal layer, which adheres relatively well to the surface of the electrode. It was found that the manganese dioxide present in the slime is of different nature: a non-adhering layer produced by electrolysis (ε-MnO2 on the PbO2 surface and a pure chemical precipitate in the solution (β- MnO2. Lead sulfate was found on the β-MnO2layer when iron was in the electrolyte. When arsenic or antimony was present in the electrolyte, the slime was lead sulfate and amorphous compounds of those ions. Slime of Chilean electrowinning (EW plants is also discussed.

    Se estudió la formación de borras anódicas debido a la presencia de varias impurezas metálicas en electrólitos de cobre. Sobre la superficie de un ánodo de Pb-Ca-Sn se forma primero PbSO4 y luego se transforma en PbO2, el cual cubre la superficie del ánodo. Se estableció experimentalmente la formación de una doble capa de dióxido de manganeso en el ánodo. Esta estuvo siempre compuesta por una capa externa gruesa, no adherente y de fácil remoción, y otra interna delgada y adherida a la superficie del electrodo. Se encontró que los óxidos de manganeso en las borras eran de distinta naturaleza: una capa no adherente producida por electrólisis sobre la superficie de PbO2 (ε-MnO2 y una producida sólo por precipitación química en la solución (β-MnO2. A1 existir hierro en el electrólito se encontró sulfato de

  13. How the velvet worm squirts slime

    CERN Document Server

    Concha, Andrés; Morera-Brenes, Bernal; Costa, Cristiano Sampaio; Mahadevan, L; Monge-Nájera, Julián

    2014-01-01

    The rapid squirt of a proteinaceous slime jet endows the ancient velvet worms (Onychophora) with a unique mechanism for defense from predators and for capturing prey by entangling them in a disordered web that immobilizes their target. However, to date neither qualitative nor quantitative descriptions have been provided for this unique adaptation. Here we investigate the fast oscillatory motion of the oral papillae and the exiting liquid jet that oscillates with frequencies $f\\sim 30-60$ Hz. Using anatomical images, high speed videography, theoretical analysis and a physical simulacrum we show that this fast oscillatory motion is the result of an elastohydrodynamic instability driven by the interplay between the elasticity of oral papillae and the fast unsteady flow during squirting. Our results demonstrate how passive strategies can be cleverly harnessed by organisms, while suggesting future oscillating micro-fluidic devices as well as novel ways for micro and nano fiber production using bioinspired strategi...

  14. Vie Physarale: Evaluation of Roman roads with slime mould

    CERN Document Server

    Strano, Emanuele; Jones, Jeff

    2012-01-01

    Roman Empire is renowned for sharp logical design and outstanding building quality of its road system. Many roads built by Romans are still use in continental Europe and UK. The Roman roads were built for military transportations with efficiency in mind, as straight as possible. Thus the roads make an ideal test-bed for developing experimental laboratory techniques for evaluating man-made transport systems using living creatures. We imitate development of road networks in Iron Age Italy using slime mould Physarum polycephalum. We represent ten Roman cities with oat flakes, inoculate the slime mould in Roma, wait till slime mould spans all flakes-cities with its network of protoplasmic tubes, and analyse structures of the protoplasmic networks. We found that most Roman roads, apart of those linking Placentia to Bononia and Genua to Florenzia are represented in development of Physarum polycephalum. Transport networks developed by Romans and by slime mould show strong affinity of planar proximity graphs, and par...

  15. Production and characterization of the slime polysaccharide of Pseudomonas aeruginosa.

    Science.gov (United States)

    Evans, L R; Linker, A

    1973-11-01

    The slime polysaccharides produced by Pseudomonas aeruginosa isolated from a variety of human infections were investigated. Slime production in culture seemed optimal when adequate amounts of carbohydrate were present and under conditions of either high osmotic pressure or inadequate protein supply. The polysaccharides produced by the organisms were similar to each other, to the slime of Azotobacter vinelandii, and to seaweed alginic acids. They were composed of beta-1,4-linked d-mannuronic acid residues and variable amounts of its 5-epimer l-guluronic acid. All bacterial polymers contained o-acetyl groups which are absent in the alginates. The polysaccharides differed considerably in the ratio of mannuronic to guluronic acid content and in the number of o-acetyl groups. The particular composition of the slime was not found to be characteristic for the disease process from which the mucoid variants of P. aeruginosa were obtained.

  16. Are motorways rational from slime mould's point of view?

    CERN Document Server

    Adamatzky, Andrew; Alonso-Sanz, Ramon; van Dessel, Wesley; Ibrahim, Zuwairie; Ilachinski, Andrew; Jones, Jeff; Kayem, Anne V D M; Martinez, Genaro J; de Oliveira, Pedro; Prokopenko, Mikhail; Schubert, Theresa; Sloot, Peter; Strano, Emanuele; Yang, Xin-She

    2012-01-01

    We analyse the results of our experimental laboratory approximation of motorways networks with slime mould Physarum polycephalum. Motorway networks of fourteen geographical areas are considered: Australia, Africa, Belgium, Brazil, Canada, China, Germany, Iberia, Italy, Malaysia, Mexico, The Netherlands, UK, USA. For each geographical entity we represented major urban areas by oat flakes and inoculated the slime mould in a capital. After slime mould spanned all urban areas with a network of its protoplasmic tubes we extracted a generalised Physarum graph from the network and compared the graphs with an abstract motorway graph using most common measures. The measures employed are the number of independent cycles, cohesion, shortest paths lengths, diameter, the Harary index and the Randic index. We obtained a series of intriguing results, and found that the slime mould approximates best of all the motorway graphs of Belgium, Canada and China, and that for all entities studied the best match between Physarum and ...

  17. Mold Testing or Sampling

    Science.gov (United States)

    In most cases, if visible mold growth is present, sampling is unnecessary. Since no EPA or other federal limits have been set for mold or mold spores, sampling cannot be used to check a building's compliance with federal mold standards.

  18. Molds in the Environment

    Science.gov (United States)

    ... on Facebook Tweet Share Compartir Molds in the Environment What are molds? What are some of the ... molds found? Molds are found in virtually every environment and can be detected, both indoors and outdoors, ...

  19. Darcy permeability of hagfish slime: an ultra-soft hydrogel

    Science.gov (United States)

    Chaudhary, Gaurav; Fudge, Douglas; Ewoldt, Randy

    2016-11-01

    When under attack from predators, hagfish produces a large amount of slime. The slime is an exceptional hydrogel, which sets-up in fraction of a second and is known to choke the predators. A small quantity of exudate, released from specialized slime glands, mixes with a large volume of sea water (99.996% w/v) and forms a mucus-like cohesive mass. The exudate has two main constituents: mucins and long intermediate filament based threads. This remarkably dilute material forms into a solid and is hypothesized to have a low hydrodynamic permeability. In this work, we present the first experimental measurements of Darcy permeability of hagfish slime. Our results explain how this ultra-soft hydrogel possesses the so-called 'gill-clogging' ability. We also investigate the roles played by individual components of slime, namely, thread cells and mucins, via a concentration-dependent permeability study. Our results provide vital insights into the roles of individual components and it is evident from our observations that mucins play a vital role in significantly reducing the permeability of the fibrous network formed by threads.

  20. Collective behaviour and swarm intelligence in slime moulds.

    Science.gov (United States)

    Reid, Chris R; Latty, Tanya

    2016-08-29

    The study of collective behaviour aims to understand how individual-level behaviours can lead to complex group-level patterns. Collective behaviour has primarily been studied in animal groups such as colonies of insects, flocks of birds and schools of fish. Although less studied, collective behaviour also occurs in microorganisms. Here, we argue that slime moulds are powerful model systems for solving several outstanding questions in collective behaviour. In particular, slime mould may hold the key to linking individual-level mechanisms to colony-level behaviours. Using well-established principles of collective animal behaviour as a framework, we discuss the extent to which slime mould collectives are comparable to animal groups, and we highlight some potentially fruitful areas for future research.

  1. Recovery of Silver and Gold from Copper Anode Slimes

    Science.gov (United States)

    Chen, Ailiang; Peng, Zhiwei; Hwang, Jiann-Yang; Ma, Yutian; Liu, Xuheng; Chen, Xingyu

    2015-02-01

    Copper anode slimes, produced from copper electrolytic refining, are important industrial by-products containing several valuable metals, particularly silver and gold. This article provides a comprehensive overview of the development of the extraction processes for recovering silver and gold from conventional copper anode slimes. Existing processes, namely pyrometallurgical processes, hydrometallurgical processes, and hybrid processes involving the combination of pyrometallurgical and hydrometallurgical technologies, are discussed based in part on a review of the form and characteristics of silver and gold in copper anode slimes. The recovery of silver and gold in pyrometallurgical processes is influenced in part by the slag and matte/metal chemistry and related characteristics, whereas the extraction of these metals in hydrometallurgical processes depends on the leaching reagents used to break the structure of the silver- and gold-bearing phases, such as selenides. By taking advantage of both pyrometallurgical and hydrometallurgical techniques, high extraction yields of silver and gold can be obtained using such combined approaches that appear promising for efficient extraction of silver and gold from copper anode slimes.

  2. Anti-ulcer potentials of phylum mollusca (tropical snail) slime

    Institute of Scientific and Technical Information of China (English)

    Nwodo NJ; Okonta J M; Ezugwu CO; Attama AA

    2009-01-01

    Objective:The effectiveness of the slimy substance in snail to regenerate and repair damaged areas on its body/shell lead to this investigation.Methods:The anti-ulcer'property of snail slime extracted from phylum mollusca (tropical snail)from the giant African snail Archachatina marginata (Fam.Arionidae)was investi-gated using histamine,stress and indomethacin-induced ulcers.The solubility profile of extract was investiga-ted in different solvents and at different temperatures.Chemical analysis was carried out to determine the types of constituents present in the slim,while acute toxicity test was carried out to evaluate its profile of toxicity. The effect of the snail slim on gastrointestinal motility was investigated in mice,while the guinea pig ileum was used to study the effect of the extract on contraction produced by acetylcholine and histamine.The snail slime contained copious quantity of protein,with varying amounts of simple sugars,carbohydrates and fats.The slime was not soluble in most common solvents and increases in temperature,did not appear to increase its sol-ubility.Results:The result further indicated that although the snail slime exhibited significant (P <0.05)an-ti-ulcer induced by stress and histamine,it was most potent against ulcer induced by indomethacin.The snail slime potently inhibited gastrointestinal movement in mice in a dose-dependent manner;however,it was not a-ble to inhibit contraction induced by acetylcholine and histamine in guinea pig ileum.Conclusion:The snail mucin possesses potent antiulcer properties without any toxic effect.The mechanism responsible for the anti-ul-cer property may not be postulated with certainty but cytoprotective and anti-spasmodic activities are most likely to be involved.

  3. Hagfish slime and mucin flow properties and their implications for defense

    Science.gov (United States)

    Böni, Lukas; Fischer, Peter; Böcker, Lukas; Kuster, Simon; Rühs, Patrick A.

    2016-07-01

    When hagfish (Myxinidae) are attacked by predators, they form a dilute, elastic, and cohesive defensive slime made of mucins and protein threads. In this study we propose a link between flow behavior and defense mechanism of hagfish slime. Oscillatory rheological measurements reveal that hagfish slime forms viscoelastic networks at low concentrations. Mucins alone did not contribute viscoelasticity, however in shear flow, viscosity was observed. The unidirectional flow, experienced by hagfish slime during suction feeding by predators, was mimicked with extensional rheology. Elongational stresses were found to increase mucin viscosity. The resulting higher resistance to flow could support clogging of the attacker’s gills. Shear flow in contrast decreases the slime viscosity by mucin aggregation and leads to a collapse of the slime network. Hagfish may benefit from this collapse when trapped in their own slime and facing suffocation by tying a sliding knot with their body to shear off the slime. This removal could be facilitated by the apparent shear thinning behavior of the slime. Therefore hagfish slime, thickening in elongation and thinning in shear, presents a sophisticated natural high water content gel with flow properties that may be beneficial for both, defense and escape.

  4. The effects of four different drugs administered through catheters on slime production in coagulase negative Staphylococci

    Directory of Open Access Journals (Sweden)

    J. Sedef Göçmen

    2012-12-01

    Full Text Available Objectives: Higher rate of slime production has been found in pathogen bacteria strains. Accordingly, the factors thatcontribute to higher slime production rate increase the infection risk, while the factors that reduce the slime productionrate will reduce the infection risk. The effect of some drugs that are administered through catheters in intensive careunits on slime production with coagulase negative Staphylococci was investigated.Materials and methods: In this study, the effect of four different preparations containing Glyceryl trinitrate (Perlinganit®, Dexmedetomidine (Precedex®, Esmolol (Brevibloc®, and Propofol (Propofol® on slime production of 24Staphylococcus epidermidis strains isolated from blood cultures of patients, and reference strain were investigated. Slimeproduction was determined using ‘the quantitative microdilution plaque test’ described by Christensen.Results: Under controlled medium, eight strains formed slimes, and in the media containing esmolol, glyceryl trinitrate,dexmedetomidine, and propofol slimes were positive for five, 21, 15, and 18 strains, respectively. The rate of slime productionin glyceryl trinitrate, dexmedetomidine, and propofol containing media were higher than that of the controls.Conclusions: In the light of the results of this study, it is concluded that the drugs and/or additives increase the rate ofslime production. The effects of the preparations administered through catheters on slime production should be investigated,and these effects should be kept in mind during their use. J Microbiol Infect Dis 2012; 2(4: 150-154Key words: Slime Production, Coagulase Negative Staphyloccoci, Parenteral drugs

  5. DIVERSITY AND DISTRIBUTION OF PLASMODIAL MYXOMYCETES (SLIME MOLDS FROM LA MESA ECOPARK, QUEZON CITY, PHILIPPINES

    Directory of Open Access Journals (Sweden)

    THOMAS EDISON E. DELA CRUZ

    2010-10-01

    Full Text Available Myxomycetes are ubiquitous in terrestrial forest ecosystems. Thus, this research study looks at the taxonomic diversity and distribution of plasmodial myxomycetes in La Mesa Ecopark in Quezon City, Philippines. A total of 240 moist chambers were prepared from four substrates (aerial and ground leaf litter, twigs and barks collected within this ecopark. Following incubation of moist chambers for eight weeks, a total of 28 species belonging to 10 genera were collected and identified: Arcyria (3, Diderma (2, Didymium (5, Lamproderma (2, Perichaena (3, Physarum (8, Macbrideola (1, Metatrichia (1, Trichia (1 and Stemonitis (2. Highest myxomycete yield (85% was observed in aerial leaf litter. In terms of taxonomic diversity, highest diversity was observed in bark microhabitats, although the lowest number of species was recorded in it. Assessment of their abundance and distribution showed similarities in species composition between aerial and ground leaf litter. This research study is the first report of plasmodial myxomycetes in La Mesa Ecopark in Quezon City, Philippines.

  6. Processing of copper anodic-slimes for extraction of valuable metals.

    Science.gov (United States)

    Amer, A M

    2003-01-01

    This work focuses on processing of anodic slimes obtained from an Egyptian copper electrorefining plant. The anodic slimes are characterized by high concentrations of copper, lead, tin and silver. The proposed hydrometallurgical process consists of two leaching stages for the extraction of copper (H(2)SO(4)-O(2)) and silver (thiourea-Fe3+), and pyrometallurgical treatment of the remaining slimes for production of Pb-Sn soldering alloy. Factors affecting both the leaching and smelting stages were studied.

  7. Demonstration of the Coagulation and Diffusion of Homemade Slime Prepared under Acidic Conditions without Borate

    Science.gov (United States)

    Isokawa, Naho; Fueda, Kazuki; Miyagawa, Korin; Kanno, Kenichi

    2015-01-01

    Poly(vinyl alcohol) (PVA) precipitates in many kinds of aqueous salt solutions. While sodium sulfate, a coagulant for PVA fiber, precipitates PVA to yield a white rigid gel, coagulation of PVA with aluminum sulfate, a coagulant for water treatment, yields a slime-like viscoelastic fluid. One type of homemade slime is prepared under basic…

  8. Bleach Neutralizes Mold Allergens

    Science.gov (United States)

    Science Teacher, 2005

    2005-01-01

    Researchers at National Jewish Medical and Research Center have demonstrated that dilute bleach not only kills common household mold, but may also neutralize the mold allergens that cause most mold-related health complaints. The study, published in the Journal of Allergy and Clinical Immunology, is the first to test the effect on allergic…

  9. Recovery Of Valuable Metals In Tin-Based Anodic Slimes By Carbothermic Reaction

    Directory of Open Access Journals (Sweden)

    Han Chulwoong

    2015-06-01

    Full Text Available This study investigated the recovery of anodic slimes by carbothermic reaction in the temperature range of 973~1,273K and amount of carbon as a function of time. Tin anodic slime samples were collected from the bottom of the electrolytic cells during the electro-refining of tin. The anodic slimes are consisted of high concentrated tin, silver, copper and lead oxides. The kinetics of reduction were determined by means of the weight-loss measurement technique. In order to understand in detail of carbothermic reaction, thermodynamic calculation was carried out and compared with experiments. From thermodynamic calculation and experiment, it was confirmed that Sn-based anodic slime could be reduced by controlling temperature and amount of carbon. However, any tendency between the reduction temperature and carbon content for the reduction reaction was not observed.

  10. Phenolic Molding Compounds

    Science.gov (United States)

    Koizumi, Koji; Charles, Ted; de Keyser, Hendrik

    Phenolic Molding Compounds continue to exhibit well balanced properties such as heat resistance, chemical resistance, dimensional stability, and creep resistance. They are widely applied in electrical, appliance, small engine, commutator, and automotive applications. As the focus of the automotive industry is weight reduction for greater fuel efficiency, phenolic molding compounds become appealing alternatives to metals. Current market volumes and trends, formulation components and its impact on properties, and a review of common manufacturing methods are presented. Molding processes as well as unique advanced techniques such as high temperature molding, live sprue, and injection/compression technique provide additional benefits in improving the performance characterisitics of phenolic molding compounds. Of special interest are descriptions of some of the latest innovations in automotive components, such as the phenolic intake manifold and valve block for dual clutch transmissions. The chapter also characterizes the most recent developments in new materials, including long glass phenolic molding compounds and carbon fiber reinforced phenolic molding compounds exhibiting a 10-20-fold increase in Charpy impact strength when compared to short fiber filled materials. The role of fatigue testing and fatigue fracture behavior presents some insight into long-term reliability and durability of glass-filled phenolic molding compounds. A section on new technology outlines the important factors to consider in modeling phenolic parts by finite element analysis and flow simulation.

  11. Mold design with simulation for chalcogenide glass precision molding

    Science.gov (United States)

    Zhang, Yunlong; Wang, Zhibin; Li, Junqi; Zhang, Feng; Su, Ying; Wang, Zhongqiang

    2016-10-01

    Compare with the manufacturing of the traditional infrared material, such as signal crystal germanium, zinc sulfide, zinc selenide etc, chalcogenide infrared glass is suitable for precision molding for the low soften temperature to have large mass industry production. So the researches of precision glass molding are necessary, especially for the fast development of infrared product. The mold design is one of the key technologies of precision glass molding. In this paper, the mold processing of a sample chalcogenide glass from the technical drawing, mold design, molding to the lens are introduced. From the result of the precision molding, the technology of finite element simulation is a useful way to guiding the mold design. The molded lens by using mold process fit the design requirement.

  12. Silicon micro-mold

    Science.gov (United States)

    Morales, Alfredo M.

    2006-10-24

    The present invention describes a method for rapidly fabricating a robust 3-dimensional silicon-mold for use in preparing complex metal micro-components. The process begins by depositing a conductive metal layer onto one surface of a silicon wafer. A thin photoresist and a standard lithographic mask are then used to transfer a trace image pattern onto the opposite surface of the wafer by exposing and developing the resist. The exposed portion of the silicon substrate is anisotropically etched through the wafer thickness down to conductive metal layer to provide an etched pattern consisting of a series of rectilinear channels and recesses in the silicon which serve as the silicon micro-mold. Microcomponents are prepared with this mold by first filling the mold channels and recesses with a metal deposit, typically by electroplating, and then removing the silicon micro-mold by chemical etching.

  13. Glass molding process with mold lubrication

    Science.gov (United States)

    Davey, Richard G.

    1978-06-27

    Improvements are provided in glass forming processes of the type wherein hot metal blank molds are employed by using the complementary action of a solid film lubricant layer, of graphite dispersed in a cured thermoset organopolysiloxane, along with an overspray of a lubricating oil.

  14. Vacuum Carbothermal Reduction for Treating Tin Anode Slime

    Science.gov (United States)

    Li, Wei; Guo, Weizhong; Qiu, Keqiang

    2013-11-01

    In this work, a process of vacuum carbothermal reduction was proposed for treating tin anode slime containing antimony and lead. During vacuum carbothermal reduction, the antimony and lead were selectively removed simultaneously by reducing and decomposing the less volatile mixed oxide of lead and antimony into the more volatile Sb2O3 and PbO. Then the tin was enriched in the distilland and primarily present as SnO2. Crude tin was obtained via vacuum reduction of the residual SnO2. The results showed that 92.85% by weight of antimony and 99.58% by weight of lead could be removed at 850°C for 60 min with 4 wt.% of reductant and air flow rate at 400 mL/min corresponding to the residual gas pressure of 40 Pa-150 Pa. Under these conditions, an evaporation ratio of 52.7% was achieved. Crude tin with a tin content of 94.22 wt.% was obtained at temperature of 900°C, reduction time of 60 min, reductant dosage of 12.5 wt.%, and a residual gas pressure of 40 Pa-400 Pa. Correspondingly, the direct recovery of tin was 94.35%.

  15. Deep phylogeny and evolution of slime moulds (mycetozoa).

    Science.gov (United States)

    Fiore-Donno, Anna Maria; Nikolaev, Sergey I; Nelson, Michaela; Pawlowski, Jan; Cavalier-Smith, Thomas; Baldauf, Sandra L

    2010-01-01

    Mycetozoa, characterized by spore-bearing fruiting bodies, are the most diverse Amoebozoa. They traditionally comprise three taxa: Myxogastria, Dictyostelia and Protostelia. Myxogastria and Dictyostelia typically have multispored fruiting bodies, but controversy exists whether they are related or arose independently from different unicellular ancestors. Protostelid slime moulds, with single-spored fruiting bodies, are possible evolutionary intermediates between them and typical amoebae, but have received almost no molecular study. Protostelid morphology is so varied that they might not be monophyletic. We therefore provide 38 new 18S rRNA and/or EF-1alpha gene sequences from Mycetozoa and related species, including four protostelids and the enigmatic Ceratiomyxa fruticulosa. Phylogenetic analyses support the monophyly of Dictyostelia, Myxogastria, and Ceratiomyxa (here collectively called "macromycetozoa") and show that protostelids are Amoebozoa, mostly related to non-fruiting amoebae of the class Variosea, but may not be monophyletic; some phylogenetic relationships remain poorly resolved. Ceratiomyxa fruticulosa, originally regarded as a myxogastrid, but in recent decades included in Protostelia, is a deeply diverging sister to Myxogastria. The protostelids studied here plus varipodid amoebae and the flagellates Phalansterium and Multicilia together probably form the outgroup to macromycetozoa plus Archamoebae. Thus protostelids and Variosea are especially significant for understanding the evolutionary transition from solitary amoebae to macromycetozoa.

  16. Mold Image Library

    Science.gov (United States)

    Jump to main content US EPA United States Environmental Protection Agency Search Search Mold Share Facebook Twitter Google+ ... the foundation of this house Fix: It is important that the water drain away from the foundation— ...

  17. Transferability of glass lens molding

    Science.gov (United States)

    Katsuki, Masahide

    2006-02-01

    Sphere lenses have been used for long time. But it is well known that sphere lenses theoretically have spherical aberration, coma and so on. And, aspheric lenses attract attention recently. Plastic lenses are molded easily with injection machines, and are relatively low cost. They are suitable for mass production. On the other hand, glass lenses have several excellent features such as high refractive index, heat resistance and so on. Many aspheric glass lenses came to be used for the latest digital camera and mobile phone camera module. It is very difficult to produce aspheric glass lenses by conventional process of curve generating and polishing. For the solution of this problem, Glass Molding Machine was developed and is spreading through the market. High precision mold is necessary to mold glass lenses with Glass Molding Machine. The mold core is ground or turned by high precision NC aspheric generator. To obtain higher transferability of the mold core, the function of the molding machine and the conditions of molding are very important. But because of high molding temperature, there are factors of thermal expansion and contraction of the mold and glass material. And it is hard to avoid the factors. In this session, I introduce following items. [1] Technology of glass molding and the machine is introduced. [2] The transferability of glass molding is analyzed with some data of glass lenses molded. [3] Compensation of molding shape error is discussed with examples.

  18. Characterization of Raw and Decopperized Anode Slimes from a Chilean Refinery

    Science.gov (United States)

    Melo Aguilera, Evelyn; Hernández Vera, María Cecilia; Viñals, Joan; Graber Seguel, Teófilo

    2016-04-01

    This work characterizes raw and decopperized slimes, with the objective of identifying the phases in these two sub-products. The main phases in copper anodes are metallic copper, including CuO, which are present in free form or associated with the presence of copper selenide or tellurides (Cu2(Se,Te)) and several Cu-Pb-Sb-As-Bi oxides. During electrorefining, the impurities in the anode release and are not deposited in the cathode, part of them dissolving and concentrated in the electrolyte, and others form a raw anode slime that contains Au, Ag, Cu, As, Se, Te and PGM, depending on the composition of the anode. There are several recovery processes, most of which involve acid leaching in the first step to dissolve copper, whose product is decopperized anode slime. SEM analysis revealed that the mineralogical species present in the raw anode slime under study were mainly eucarite (CuAgSe), naumannite (Ag2Se), antimony arsenate (SbAsO4), and lead sulfate (PbSO4). In the case of decopperized slime, the particles were mainly composed of SbAsO4 (crystalline appearance), non-stoichiometric silver selenide (Ag(2- x)Se), and chlorargyrite (AgCl).

  19. Hagfish slime threads as a biomimetic model for high performance protein fibres

    Energy Technology Data Exchange (ETDEWEB)

    Fudge, Douglas S; Hillis, Sonja [Department of Integrative Biology, University of Guelph, Guelph, Ontario, N1G 2W1 (Canada); Levy, Nimrod; Gosline, John M, E-mail: dfudge@uoguelph.c [Department of Zoology, University of British Columbia, Vancouver, British Columbia, V6T 1Z4 (Canada)

    2010-09-15

    Textile manufacturing is one of the largest industries in the world, and synthetic fibres represent two-thirds of the global textile market. Synthetic fibres are manufactured from petroleum-based feedstocks, which are becoming increasingly expensive as demand for finite petroleum reserves continues to rise. For the last three decades, spider silks have been held up as a model that could inspire the production of protein fibres exhibiting high performance and ecological sustainability, but unfortunately, artificial spider silks have yet to fulfil this promise. Previous work on the biomechanics of protein fibres from the slime of hagfishes suggests that these fibres might be a superior biomimetic model to spider silks. Based on the fact that the proteins within these 'slime threads' adopt conformations that are similar to those in spider silks when they are stretched, we hypothesized that draw processing of slime threads should yield fibres that are comparable to spider dragline silk in their mechanical performance. Here we show that draw-processed slime threads are indeed exceptionally strong and tough. We also show that post-drawing steps such as annealing, dehydration and covalent cross-linking can dramatically improve the long-term dimensional stability of the threads. The data presented here suggest that hagfish slime threads are a model that should be pursued in the quest to produce fibres that are ecologically sustainable and economically viable.

  20. Ag recovery from copper anode slime by acid leaching at atmospheric pressure to synthesize silver nanoparticles

    Institute of Scientific and Technical Information of China (English)

    Atefeh Khaleghi; Sattar Ghader; Dariush Afzali

    2014-01-01

    In this paper, recovery of silver from anode slime of Sarcheshmeh copper complex in Iran and subsequent synthesis of silver nanoparticles from leaching solution is investigated. Sarcheshmeh anode slime is mainly consisted of Cu, Ag, Pb and Se. Amount of Ag in the considered anode slime was 5.4%(by weight). The goal was to recover as much as possible Ag from anode slime at atmospheric pressure to synthesize Ag nanoparticles. Therefore, acid leaching was used for this purpose. The anode slime was leached with sulfuric and nitric acid from room to 90 ?C at different acid concentrations and the run which yielded the most recovery of Ag was selected for Ag nanoparticles synthesis. At this condition, Cu, Pb and Se are lea-ched as well as Ag. To separate Ag from leach solution HCl was added and silver was precipitated as AgCl which were then dissolved by ammonia solution. The Ag nanoparticles are synthesized from this solution by chemical reduction method by aid of sodium borohydride in the presence of PVP and PEG as stabiliz-ers. The synthesized Ag nanoparticles showed a peak of 394 nm in UV-vis spectrum and TEM images showed a rather uniform Ag nanoparticles of 12 nm.

  1. Dynamic of taking out molding parts at injection molding

    Directory of Open Access Journals (Sweden)

    E. Ragan

    2012-10-01

    Full Text Available Most plastic parts used in automobile production are manufactured by injection molding. Their quality depends also on taking out molding and on the manipulators for it. Task of this contribution is to theoretically describe a transport of molding at taking out after injection molding in relation on its regulation. The following quantities are derived at it: the transition characteristic of the taking out system, the blocking diagram of taking out molding regulation, the amplitude and phase characteristic and the transition characteristic of action quantity at taking out molding regulation.

  2. Slime mould imitation of Belgian transport networks: redundancy, bio-essential motorways, and dissolution

    CERN Document Server

    Adamatzky, Andrew; Van Dessel, Wesley

    2011-01-01

    Belgium is amongst few artificial countries, established on purpose, when Dutch and French speaking parts were joined in a single unit. This makes Belgium a particularly interesting testbed for studying bio-inspired techniques for simulation and analysis of vehicular transport networks. We imitate growth and formation of a transport network between major urban areas in Belgium using the acellular slime mould Physarum polycephalum. We represent the urban areas with the sources of nutrients. The slime mould spans the sources of nutrients with a network of protoplasmic tubes. The protoplasmic tubes represent the motorways. In an experimental laboratory analysis we compare the motorway network approximated by P. polycephalum and the man-made motorway network of Belgium. We evaluate the efficiency of the slime mould network and the motorway network using proximity graphs.

  3. Bacterial gliding fluid dynamics on a layer of non-Newtonian slime: Perturbation and numerical study.

    Science.gov (United States)

    Ali, N; Asghar, Z; Anwar Bég, O; Sajid, M

    2016-05-21

    Gliding bacteria are an assorted group of rod-shaped prokaryotes that adhere to and glide on certain layers of ooze slime attached to a substratum. Due to the absence of organelles of motility, such as flagella, the gliding motion is caused by the waves moving down the outer surface of these rod-shaped cells. In the present study we employ an undulating surface model to investigate the motility of bacteria on a layer of non-Newtonian slime. The rheological behavior of the slime is characterized by an appropriate constitutive equation, namely the Carreau model. Employing the balances of mass and momentum conservation, the hydrodynamic undulating surface model is transformed into a fourth-order nonlinear differential equation in terms of a stream function under the long wavelength assumption. A perturbation approach is adopted to obtain closed form expressions for stream function, pressure rise per wavelength, forces generated by the organism and power required for propulsion. A numerical technique based on an implicit finite difference scheme is also employed to investigate various features of the model for large values of the rheological parameters of the slime. Verification of the numerical solutions is achieved with a variational finite element method (FEM). The computations demonstrate that the speed of the glider decreases as the rheology of the slime changes from shear-thinning (pseudo-plastic) to shear-thickening (dilatant). Moreover, the viscoelastic nature of the slime tends to increase the swimming speed for the shear-thinning case. The fluid flow in the pumping (generated where the organism is not free to move but instead generates a net fluid flow beneath it) is also investigated in detail. The study is relevant to marine anti-bacterial fouling and medical hygiene biophysics.

  4. [Extracellular slime production and adhesion of Morganella morganii strains to polystyrene].

    Science.gov (United States)

    Michalska, Anna; Zalas-Wiecek, Patrycja; Sielska, Barbara; Gospodarek, Eugenia

    2011-01-01

    The aim of this study was the evaluation of the ability of extracellular slime production and adhesive properties of M. morganii strains. This study included 50 of M. morganii strains isolated from clinical samples. All of these strains were isolated in the Clinical Microbiology Department of dr. A. Jurasz University Hospital in 2008-2009. Five (10.0%) out of 50. M. morganii strains demonstrated extracellular slime production. Adherence to polystyrene revealed 36 (72.0%) of M. morganii strains in it 6 strains (12.0%) adhered strongly, medium - 12 (24.0%) and weakly - 18 (36.0%).

  5. Meer bekend over Black Mold

    NARCIS (Netherlands)

    Duyvesteijn, R.G.E.; Kohrman, E.

    2008-01-01

    In de vollegrondsrozenteelt zorgde Black Mold in 2007 voor een groot aantal mislukte oculaties. In 2008 waren er aanzienlijk minder problemen. Uit onderzoek is meer bekend over de oorzaak en bestrijding van Black Mold.

  6. Diversity of plasmodial slime molds (myxomycetes in coastal, mountain, and community forests of Puerto Galera, Oriental Mindoro, the Philippines

    Directory of Open Access Journals (Sweden)

    Nikki Heherson A. Dagamac

    2015-12-01

    Full Text Available No profiling of diversity of myxomycetes has ever been conducted in one of the biodiversity hotspot areas in the Philippine archipelago, and this necessitates a swift survey of myxomycetes in Puerto Galera, Oriental Mindoro. An assessment of diversity of myxomycetes collected from seven collecting points of three different forest types in the study area showed a total of 926 records of myxomycetes. Of which, 42 morphospecies belonging to 16 genera are reported in this study. Species richness of myxomycetes was higher in collecting points that were found in inland lowland mountain forests, but the most taxonomically diverse species was found in coastal forests. Myxomycete species, namely, Arcyria cinerea, Diderma hemisphaericum, Physarum echinosporum, Lamproderma scintillans, and Stemonitis fusca, were found in all the collecting points. Manmade disturbances and forest structure may affect the occurrence of myxomycetes.

  7. The mitochondrial plasmid of the true slime mold Physarum polycephalum bypasses uniparental inheritance by promoting mitochondrial fusion.

    Science.gov (United States)

    Sakurai, Rakusa; Nomura, Hideo; Moriyam, Yohsuke; Kawano, Shigeyuki

    2004-08-01

    Mitochondrial DNA (mtDNA) is inherited maternally in most eukaryotes. Linear mitochondrial plasmids in higher plants and fungi are also transmitted from the maternal parent to the progeny. However, mF, which is a mitochondrial linear plasmid of Physarum polycephalum, evades uniparental mitochondrial inheritance. We examined 36 myxamoebal strains of Physarum and isolated three novel mF+ strains (JE8, TU111, NG111) that harbored free mF plasmids. These strains were mated with the mF- strain KM88. Of the three mF- x mF+ crosses, only KM88 x JE8 displayed complete uniparental inheritance. However, in KM88 x TU111 and KM88 x NG111, the mtDNA of KM88 and mF of TU111 and NG111 were inherited by the plasmodia and showed recombination. For example, although the mtDNA of TU111 was eliminated, the mF of TU111 persisted and became inserted into the mtDNA of KM88, such that recombinant mtDNA represented 80% of the total mtDNA. The parental mitochondria fused to yield giant mitochondria with two or more mitochondrial nucleoids. The mF appears to exchange mitochondria from the recipient (paternal) to the donor (maternal) by promoting mitochondrial fusion.

  8. Phase separation micro molding

    NARCIS (Netherlands)

    Vogelaar, Laura

    2005-01-01

    The research described in this thesis concerns the development of a new microfabrication method, Phase Separation Micro Molding (PSμM). While microfabrication is still best known from semiconductor industry, where it is used to integrate electrical components on a chip, the scope has immensely expan

  9. Intensification of pretreatment and pressure leaching of copper anode slime by microwave radiation

    Institute of Scientific and Technical Information of China (English)

    杨洪英; 马致远; 黄松涛; 吕阳; 熊柳

    2015-01-01

    The application of microwave irradiation for pretreatment of copper anode slime with high nickel content prior to pressure sulfuric acid leaching has been proposed. The microwave-assisted pretreatment is a rapid and efficient process. Through the technology of microwave assisted pretreatment-pressure leaching of copper anode slime, copper, tellurium, selenium and nickel are almost completely recovered. Under optimal conditions, the leaching efficiencies of copper, tellurium, selenium and nickel are 97.12%, 95.97%, 95.37% and 93.90%, respectively. The effect of microwave radiation on the temperature of copper anode slime and leaching solution is investigated. It is suggested that the enhancement on the recoveries of copper, tellurium and selenium can be attributed to the temperature gradient which is caused by shallow microwave penetration depth and super heating occurring at the solid–liquid interface. The kinetic study shows that the pressure leaching of copper anode slime, with and without microwave assisted pretreatment, are both controlled by chemical reactions on the surfaces of particles. It is found that the activation energy calculated for microwave-assisted pretreatment-pressure leaching (49.47 kJ/mol) is lower than that for pressure leaching which is without microwave assisted pretreatment (60.57 kJ/mol).

  10. Structural elucidation of the EPS of slime producing Brevundimonas vesicularis sp isolated from a paper machine

    NARCIS (Netherlands)

    Verhoef, R.P.; Waard, de P.; Schols, H.A.; Ratto, M.; Siika-aho, M.; Voragen, A.G.J.

    2002-01-01

    The slime forming bacteria Brevundimonas vesicularis sp. was isolated from a paper mill and its EPS was produced on laboratory scale. After production, the exopolysaccharide (EPS) was purified and analysed for its purity and homogeneity, HPSEC revealed one distinct population with a molecular mass o

  11. Colanic acid is an exopolysaccharide common to many enterobacteria isolated from paper-machine slimes

    NARCIS (Netherlands)

    Ratto, M.; Verhoef, R.P.; Suihko, M.L.; Blanco, A.; Schols, H.A.; Voragen, A.G.J.; Wilting, R.; Siika-aho, M.; Buchert, J.

    2006-01-01

    In this study, polysaccharide-producing bacteria were isolated from slimes collected from two Finnish and one Spanish paper mill and the exopolysaccharides (EPSs) produced by 18 isolates were characterised. Most of the isolates, selected on the bases of slimy colony morphology, were members of the f

  12. High Cost/High Risk Components to Chalcogenide Molded Lens Model: Molding Preforms and Mold Technology

    Energy Technology Data Exchange (ETDEWEB)

    Bernacki, Bruce E.

    2012-10-05

    This brief report contains a critique of two key components of FiveFocal's cost model for glass compression molding of chalcogenide lenses for infrared applications. Molding preforms and mold technology have the greatest influence on the ultimate cost of the product and help determine the volumes needed to select glass molding over conventional single-point diamond turning or grinding and polishing. This brief report highlights key areas of both technologies with recommendations for further study.

  13. The Gelation of Polyvinyl Alcohol with Borax: A Novel Class Participation Experiment Involving the Preparation and Properties of a "Slime."

    Science.gov (United States)

    Casassa, E. Z.; And Others

    1986-01-01

    Background information, procedures used, and typical results obtained are provided for an experiment in which students prepare and study the characteristics of a "slime." A list of general, inorganic, and polymer chemistry concepts fostered in the experiment is included. (JN)

  14. Atividade enzimática, produção de slime e sensibilidade a antifúngicos de Candida sp Enzymatic activity, slime production and antifungal agent sensitivity of Candida sp

    Directory of Open Access Journals (Sweden)

    Jaqueline Otero Silva

    2007-06-01

    Full Text Available A habilidade de Candida spp secretar enzimas extracelulares e slime tem sido associada como fatores de patogenicidade. Do total de 37 cepas de Candida sp, 100% foram produtoras de proteinase, 83,8% fosfolipase, 64,9% slime e 100% sensíveis ao fluconazol e itraconazol. Foram encontradas 17 tipagens (enzima/slime. Esta metodologia apresentou um bom índice discriminatório (D=0,93 podendo ser utilizado na caracterização fenotípica das leveduras.Abilith of Candida spp to secrete extracellular enzymes and slime has been associated as pathogenicity factors. Out of a total of 37 strains of Candida sp, 100% were proteinase producers, 83.8% were phospholipase producers, 64.9% were slime producers and 100% were sensitive to fluconazole and itraconazole. Seventeen typings (enzymes/slime were found. This methodology presented a good discrimination rate (D = 0.93 and could be used for phenotypic characterization of yeasts.

  15. Evaluation of Different Phenotypic Techniques for the Detection of Slime Produced by Bacteria Isolated from Clinical Specimens

    Science.gov (United States)

    HRV, Rajkumar; Devaki, Ramakrishna

    2016-01-01

    Introduction  Microorganisms use various strategies for their survival in both the environment and in humans. Slime production by bacteria is one such mechanism by which microbes colonize on the indwelling prosthetic devices and form biofilms. Infections caused by such microorganisms are difficult to treat as the biofilm acts as a shield and protects microbes against antimicrobial agents. There are several methods for the detection of slime produced by bacteria, and they include both phenotypic and molecular methods. The present study evaluated the Congo red agar/broth method, Christensen’s method, dye elution technique, and the latex agglutination method for the demonstration of slime production by different bacterial clinical isolates. Materials & Methods We collected 151 bacterial clinical isolates (both gram-positive and gram-negative bacteria) from various specimens and tested them for the production of slime both by qualitative and quantitative tests. Congo red agar/broth method, Christensen's method, dye elution technique, and latex agglutination methods were used for detecting the slime or slime-like substance. Results  We found that 103 (68.2%) strains were positive for slime production by Congo red agar/broth method. It was found that 18 (94.7%) strains of Klebsiella pneumoniae, 21 (84.0%) strains of S aureus and 25 (65.7%) strains of coagulase-negative Staphylococci were positive for slime or slime-like substances by Congo red agar/broth method. A total of 41.0% of the strains positive by Christensen's method and 15.2% of the strains by dye elution technique were found to be more adherent organisms and that have the potential to form biofilms. Only the gram-positive organisms showed nonspecific agglutination with latex suspension. Conclusion  Among the various phenotypic methods compared in this study the Congo red agar/broth method is a simple, economical, sensitive, and specific method that can be used by clinical microbiology laboratories

  16. Polymeric Nanoelectrodes for Investigating Cellular Adhesion

    Science.gov (United States)

    Thapa, Prem; Paneru, Govind; Flanders, Bret

    2011-03-01

    Polyethylene dioxythiophene nano-filaments were grown on lithographic electrode arrays by the recently developed directed electrochemical nanowire assembly technique. These filaments are firmly attached to the electrode but are not attached to the glass substrate. Hence, they behave like cantilevered rods (with one free end). Individual cells of the slime mold Dictystolium discoideum initiate contact by extending pseudopods to the nanoelectrodes when cultured on the electrode arrays. Scanning electron micrographs of the interfaces show the contact area to be of the order of 0.1 μ m 2 . Confocal images reveal the focal adhesions in the cell-electrode contact region. Deflection of the nanoelectrode by an individual cell can be used to measure the force exerted by the cell. Recent results on this innovative force sensing approach will be discussed. NSF.

  17. Killing effect of peppermint vapor against pink-slime forming microorganisms.

    Science.gov (United States)

    Ihara, Nozomi; Sakamoto, Jin; Yoshida, Munehiro; Tsuchido, Tetsuaki

    2015-01-01

    The killing effect of peppermint vapor (PMV) against pink-slime forming microorganisms, Methylobacterium mesophilicum as a bacterium and Rhodotorula mucilaginosa as a yeast, was investigated by the agar vapor assay. In this method, microbial cells were spread over the agar surface exposed to PMV in a petri dish, and then transferred into a recovery liquid. When 60μl of the peppermint liquid was added to a paper disc, a marked killing effect of PMV was observed after 48h against M. mesophilicum and after 168h against R. mucilaginosa. M. mesophilicum and R. mucilaginosa were found to be more resistant to PMV than Escherichia coli and Candida albicans, used as reference microorganisms, respectively. With the addition of 0.03% sodium pyruvate as a hydrogen peroxide scavenger in agar, the killing effect of PMV against E. coli and C. albicans was decreased, whereas it was little changed against M. mesophilicum and R. mucilaginosa. In fact, the properties of the killing effect of hydrogen peroxide solution at 0.2-1.0mM was in accord with those of PMV. M. mesophilicum and R. mucilaginosa were more resistant to the oxidant than E. coli and C. albicans, respectively. Results obtained suggested that reactive oxygen species (ROS) may be involved in the killing action of PMV and therefore pink-slime formers are more resistant to PMV than non-pink-slime formers because of the presence of carotenoids as an antioxidant in cells. We also suggest that the use of PMV appeared to be a potential tool for the control of pink-slime forming microorganisms occurring in wet areas of houses such as the bathroom and washing room.

  18. Simulating strange attraction of acellular slime mould Physarum polycephaum to herbal tablets

    OpenAIRE

    Adamatzky, Andrew

    2012-01-01

    Plasmodium of acellular slime mould Physarum polycephalum exhibits traits of wave-like behaviour. The plasmodium's behaviour can be finely tuned in laboratory experiments by using herbal tablets. A single tablet acts as a fixed attractor: plasmodium propagates towards the tablet, envelops the tablet with its body and stays around the tablet for several days. Being presented with several tablets the plasmodium executes limit cycle like motions. The plasmodium performs sophisticated routines of...

  19. Mold and Crucible Coatings

    Science.gov (United States)

    1986-04-28

    34;" -"""-"’" " " ""’’ "" "" ’"" ’ j * AD I. AT)-E 9 7 W CONTRACTOR REPORT ARCCD-CR-86007 MOLD AND CRUCIBLE COATINGS Sylvia J. Canino Arthur L. Geary Nuclear...IFnlRpr April 1984_-_December 198, .. AUTNORfo) S. CONTRACT on CRAM? # "I MWef(e)I Sylvia J. Canino and Arthur L. Geary DAAK1O-84-C-0056 PERFORMING

  20. Nanofabrication with molds & stamps

    Directory of Open Access Journals (Sweden)

    Byron D. Gates

    2005-02-01

    Full Text Available A number of methods can be used to fabricate patterns with features having dimensions <100 nm. These techniques, however, can require specialized equipment and are often restricted to a cleanroom environment. Nanofabrication can be made accessible to multiple users by using elastomeric molds or stamps to transfer high-resolution patterns into other materials. These techniques are inexpensive and can transfer patterns into functional materials and onto a number of surfaces. This review describes recent advances in fabricating nanostructures using these techniques.

  1. Injection Compression Molding of Replica Molds for Nanoimprint Lithography

    Directory of Open Access Journals (Sweden)

    Keisuke Nagato

    2014-03-01

    Full Text Available As a breakthrough in the cost and durability of molds for nanoimprint lithography (NIL, replica molds are fabricated by injection compression molding (ICM. ICM is commonly used for optical disks such as DVDs or Blu-ray disks and is also a practical fabrication method for nanostructures. In this paper, I successfully demonstrated the fabrication of cycloolefin polymer replica molds with structures smaller than 60 nm by ICM. Furthermore, ultraviolet (UV-NIL using these replica molds was demonstrated. UV-cured resist was replicated over an area of 60 mm diameter. The degree of replication by UV-NIL in the first usage of each replica mold had good repeatability. Because ICM is a high-throughput, low-cost process, the replica mold can be disposed of after a certain time for UV-NIL. This method leads to a high-integrity UV-NIL process of patterned media because multiple large-area replica molds can be fabricated simultaneously.

  2. Enhanced Injection Molding Simulation of Advanced Injection Molds

    Directory of Open Access Journals (Sweden)

    Béla Zink

    2017-02-01

    Full Text Available The most time-consuming phase of the injection molding cycle is cooling. Cooling efficiency can be enhanced with the application of conformal cooling systems or high thermal conductivity copper molds. The conformal cooling channels are placed along the geometry of the injection-molded product, and thus they can extract more heat and heat removal is more uniform than in the case of conventional cooling systems. In the case of copper mold inserts, cooling channels are made by drilling and heat removal is facilitated by the high thermal conductivity coefficient of copper, which is several times that of steel. Designing optimal cooling systems is a complex process; a proper design requires injection molding simulations, but the accuracy of calculations depends on how precise the input parameters and boundary conditions are. In this study, three cooling circuit designs and three mold materials (Ampcoloy 940, 1.2311 (P20 steel, and MS1 steel were used and compared using numerical methods. The effect of different mold designs and materials on cooling efficiency were examined using calculated and measured results. The simulation model was adjusted to the measurement results by considering the joint gap between the mold inserts.

  3. A novel application of Fourier-transformed infrared spectroscopy: classification of slime from staphylococci.

    Science.gov (United States)

    Karadenizli, Aynur; Kolayli, Fetiye; Ergen, Kivanç

    2007-01-01

    It has been proposed that the virulence of nosocomial Staphylococcus infections associated with indwelling medical devices is related to the ability of the bacterium to colonise these materials by forming a biofilm composed of multilayered cell clusters embedded in a slime matrix. However, the pathogenic role of exopolysaccharide biofilms is not fully understood. A new method was sought for differentiating the structure of slime from two closely related bacterial strains, Staphylococcus aureus and Staphylococcus epidermidis. Using PCR it was confirmed that these strains were positive for the icaA and icaD genes and the complete ica operon (2.7 kb). Monosaccharide analysis by thin-layer chromatography revealed an identical profile for both strains, with xylose and glucose present among the four visible bands. Using Fourier-transformed infrared spectroscopy and hierarchical cluster analysis, three of four S. aureus samples (75%), and four of five S. epidermidis samples were grouped according to species. A novel FTIR approach in classifying slime produced by S. aureus and S. epidermidis is reported.

  4. Mold Materials For Permanent Molding of Aluminum Alloys

    Energy Technology Data Exchange (ETDEWEB)

    John F Wallace; David Schwam; Wen Hong dxs11@po.cwru.edu

    2001-09-14

    A test that involves immersion of the potential mod materials for permanent molds has been developed that provides a thermal cycle that is similar to the experienced during casting of aluminum in permanent molds. This test has been employed to determine the relative thermal fatigue resistance of several different types of mold materials. Four commercial mold coatings have been evaluated for their insulating ability, wear resistance and roughness. The results indicate that composition and structure of the mold materials have considerable effect on their thermal fatigue cracking behavior. Irons with a gray iron structure are the most prone to thermal fatigue cracking followed by compacted graphite irons with the least thermal fatigue cracking of the cast irons experienced by ductile iron. The composition of these various irons affects their behavior.

  5. Thermophilic molds: Biology and applications.

    Science.gov (United States)

    Singh, Bijender; Poças-Fonseca, Marcio J; Johri, B N; Satyanarayana, Tulasi

    2016-11-01

    Thermophilic molds thrive in a variety of natural habitats including soils, composts, wood chip piles, nesting materials of birds and other animals, municipal refuse and others, and ubiquitous in their distribution. These molds grow in simple media containing carbon and nitrogen sources and mineral salts. Polyamines are synthesized in these molds and the composition of lipids varies considerably, predominantly containing palmitic, oleic and linoleic acids with low levels of lauric, palmiotoleic and stearic acids. Thermophilic molds are capable of efficiently degrading organic materials by secreting thermostable enzymes, which are useful in the bioremediation of industrial wastes and effluents that are rich in oil, heavy metals, anti-nutritional factors such as phytic acid and polysaccharides. Thermophilic molds synthesize several antimicrobial substances and biotechnologically useful miscellaneous enzymes. The analysis of genomes of thermophilic molds reveals high G:C contents, shorter introns and intergenic regions with lesser repetitive sequences, and further confirms their ability to degrade agro-residues efficiently. Genetic engineering has aided in ameliorating the characteristics of the enzymes of thermophilic molds. This review is aimed at focusing on the biology of thermophilic molds with emphasis on recent developments in the analysis of genomes, genetic engineering and potential applications.

  6. Detection of methicillin resistance and slime factor production of Staphylococcus aureus in bovine mastitis Detecção de resistência a meticilina e produção do fator slime por Staphylococcus aureus em mastite bovina

    Directory of Open Access Journals (Sweden)

    Alper Ciftci

    2009-06-01

    Full Text Available This study aimed to detect methicillin resistant and slime producing Staphylococcus aureus in cases of bovine mastitis. A triplex PCR was optimized targetting 16S rRNA, nuc and mecA genes for detection of Staphylococcus species, S. aureus and methicillin resistance, respectively. Furthermore, for detection of slime producing strains, a PCR assay targetting icaA and icaD genes was performed. In this study, 59 strains were detected as S. aureus by both conventional tests and PCR, and 13 of them were found to be methicillin resistant and 4 (30.7% were positive for mecA gene. Although 22 of 59 (37.2% S. aureus isolates were slime-producing in Congo Red Agar, in PCR analysis only 15 were positive for both icaA and icaD genes. Sixteen and 38 out of 59 strains were positive for icaA and icaD gene, respectively. Only 2 of 59 strains were positive for both methicillin resistance and slime producing, phenotypically, suggesting lack of correlation between methicillin resistance and slime production in these isolates. In conclusion, the optimized triplex PCR in this study was useful for rapid and reliable detection of methicillin resistant S. aureus. Furthermore, only PCR targetting icaA and icaD may not sufficient to detect slime production and further studies targetting other ica genes should be conducted for accurate evaluation of slime production characters of S. aureus strains.Este estudo objetivou a detecção de Staphylococcus aureus resistente a meticilina e produtor do fator slime em casos de mastite bovina. Um PCR triplex foi otimizado, com alvo no genes 16SrRNA, nuc e mecA para detecção de Staphylococcus spp, S. aureus e resistencia a meticilina, respectivamente. Para detecção das cepas produtoras do fator slime, empregou-se um PCR com alvo nos genes icaA e icaD. No estudo, 59 cepas foram identificadas como S. aureus por testes convencionais e PCR, sendo 13 resistentes a meticilina e quatro positivas para o gene mecA. Embora 22 das 59 cepas

  7. Injection Molding of High Aspect Ratio Nanostructures

    DEFF Research Database (Denmark)

    Matschuk, Maria; Larsen, Niels Bent

    We present a process for injection molding of 40 nm wide and >100 nm high pillars (pitch: 200 nm). We explored the effects of mold coatings and injection molding conditions on the replication quality of nanostructures in cyclic olefin copolymer. We found that optimization of molding parameters...

  8. Rapid control of mold temperature during injection molding process

    Energy Technology Data Exchange (ETDEWEB)

    Liparoti, Sara; Titomanlio, Giuseppe [Department of Industrial Engineering, University of Salerno Via Giovanni Paolo II, 132, 84084 Fisciano (Italy); Hunag, Tsang Min; Cakmak, Mukerrem [Department of Polymer Engineering, The University of Akron, Akron, OH 44325 (United States); Sorrentino, Andrea [Institute for Polymers, Composite and Biomaterials (IPCB) - CNR, P. Enrico Fermi 1, 80055 Portici (Italy)

    2015-05-22

    The control of mold surface temperature is an important factor that determines surface morphology and its dimension in thickness direction. It can also affect the frozen molecular orientation and the mold surface replicability in injection molded products. In this work, thin thermally active films were used to quickly control the mold surface temperature. In particular, an active high electrical conductivity carbon black loaded polyimide composites sandwiched between two insulating thin polymeric layers was used to condition the mold surface. By controlling the heating time, it was possible to control precisely the temporal variation of the mold temperature surface during the entire cycle. The surface heating rate was about 40°C/s and upon contact with the polymer the surface temperature decreased back to 40°C within about 5 s; the overall cycle time increased only slightly. The effect on cross section sample morphology of samples of iPP were analyzed and discussed on the basis of the recorded temperature evolution.

  9. Onychomycosis due to opportunistic molds*

    OpenAIRE

    Martínez-Herrera, Erick Obed; Arroyo-Camarena,Stefanie; Tejada-García, Diana Luz; Porras-López, Carlos Francisco; Arenas, Roberto

    2015-01-01

    Abstract BACKGROUND: Onychomycosis are caused by dermatophytes and Candida, but rarely by non- dermatophyte molds. These opportunistic agents are filamentous fungi found as soil and plant pathogens. OBJECTIVES: To determine the frequency of opportunistic molds in onychomycosis. METHODS: A retrospective analysis of 4,220 cases with onychomycosis, diagnosed in a 39-month period at the Institute of Dermatology and Skin surgery "Prof. Dr. Fernando A. Cordero C." in Guatemala City, and confirmed w...

  10. Prevention of Mold Contamination : Ozone Treatment

    OpenAIRE

    Nakarmi, Kanchan

    2016-01-01

    Mold is a common pest that can cause diseases and decay property. Moreover, certain mold can produce toxic chemicals which leads directly or indirectly to additional health impacts and economic losses. Therefore, prevention of mold growth is a major concern, and disinfection of mold has become a center of attention. The purpose of this thesis was to study about the effect of ozone in the disinfection of mold and the method of producing ozone. The usage of ozone for disinfection in in...

  11. Hydrogen silsesquioxane mold coatings for improved replication of nanopatterns by injection molding

    DEFF Research Database (Denmark)

    Hobæk, Thor Christian; Matschuk, Maria; Kafka, Jan;

    2015-01-01

    We demonstrate the replication of nanosized pillars in polymer (cyclic olefin copolymer) by injection molding using nanostructured thermally cured hydrogen silsesquioxane (HSQ) ceramic coatings on stainless steel mold inserts with mold nanostructures produced by a simple embossing process...

  12. Properties of Solutions for a Nonlinear Parabolic-Elliptic System Modelling Chemotaxis

    Institute of Scientific and Technical Information of China (English)

    钟新华

    2002-01-01

    @@ In 1970 Keller and Segel[1] proposed a mathematical model describing chemotactic aggregation of cellular slime molds which move preferentially towards relatively high concentraions of a chemical secreted by the amoebae themselves. With the cell density of the cellular slime molds u(x, t) and the concentration of the chemical substance v(x, t) at place x and time t, a simplified Keller-Segel model is described as the system

  13. Physarum wires: Self-growing self-repairing smart wires made from slime mould

    CERN Document Server

    Adamatzky, Andrew

    2013-01-01

    We report experimental laboratory studies on developing conductive pathways, or wires, using protoplasmic tubes of plasmodium of acellular slime mould Physarum polycephalum. Given two pins to be connected by a wire, we place a piece of slime mould on one pin and an attractant on another pin. Physarum propagates towards the attract and thus connects the pins with a protoplasmic tube. A protoplasmic tube is conductive, can survive substantial over-voltage and can be used to transfer electrical current to lightning and actuating devices. In experiments we show how to route Physarum wires with chemoattractants and electrical fields. We demonstrate that Physarum wire can be grown on almost bare breadboards and on top of electronic circuits. The Physarum wires can be insulated with a silicon oil without loss of functionality. We show that a Physarum wire self-heals: end of a cut wire merge together and restore the conductive pathway in several hours after being cut. Results presented will be used in future designs ...

  14. A morphological adaptation approach to path planning inspired by slime mould

    Science.gov (United States)

    Jones, Jeff

    2015-04-01

    Path planning is a classic problem in computer science and robotics which has recently been implemented in unconventional computing substrates such as chemical reaction-diffusion computers. These novel computing schemes utilise the parallel spatial propagation of information and often use a two-stage method involving diffusive propagation to discover all paths and a second stage to highlight or visualise the path between two particular points in the arena. The true slime mould Physarum polycephalum is known to construct efficient transport networks between nutrients in its environment. These networks are continuously remodelled as the organism adapts its body plan to changing spatial stimuli. It can be guided towards attractant stimuli (nutrients, warm regions) and it avoids locations containing hazardous stimuli (light irradiation, repellents, or regions occupied by predatory threats). Using a particle model of slime mould we demonstrate scoping experiments which explore how path planning may be performed by morphological adaptation. We initially demonstrate simple path planning by a shrinking blob of virtual plasmodium between two attractant sources within a polygonal arena. We examine the case where multiple paths are required and the subsequent selection of a single path from multiple options. Collision-free paths are implemented via repulsion from the borders of the arena. Finally, obstacle avoidance is implemented by repulsion from obstacles as they are uncovered by the shrinking blob. These examples show proof-of-concept results of path planning by morphological adaptation which complement existing research on path planning in novel computing substrates.

  15. Suction characteristics of a thick material pump at high concentrations of coal slime

    Institute of Scientific and Technical Information of China (English)

    MA Xing-min; ZHAO Qiao-zhi; GAO Shao-gang; WU Miao

    2008-01-01

    A test system was designed to study the parameters affecting the volumetric efficiency of a thick-material pump for coal slime. The parameters studied included solid concentration, the slenderness ratio of the suction cylinder and the running speed of the hydraulic cylinder. In the experiment the concentrations of coal slime were 75.7%, 76.3%, 74.4%, 73.5%, 72.1% and 70.63%; the running speeds were 0.23, 0.18, 0.13, 0.10 and 0.08 m/s; and the slenderness ratios of the suction cylinder were 1.63, 2.26, 2.88, 3.50, 4.13, 4.78 and 5.38. The results show that the suction volumetric efficiency decreases gradually with an increase in material concentration. The critical concentration value is 72%; below 72% the suction volumetric efficiency is above 90%, otherwise it decreases rapidly. When the solid concentration reaches 76.3%, the suction volumetric efficiency is only 40%. When the running speed of the piston is less than or equal to 0.23 m/s, the suction volumetric efficiency increases with an increase in running speed.

  16. Functional nanostructures on injection molded plastic

    DEFF Research Database (Denmark)

    Johansson, Alicia Charlotte; Søgaard, Emil; Andersen, Nis Korsgaard

    Nanotechnology can be used to make inexpensive plastic parts with functional surfaces. The plastic parts can be molded using a standard injection molding process. The nanostructures are directly transferred from the surface of the molding tool to the surface of the molded plastic part during...... the molding process. The main advantage with this method is that surface treatments and chemical additives are avoided, which minimizes health risks and simplifies recycling. Another advantage is that the unique technology enables nanostructuring of free form molded parts. The functional surfaces can have...

  17. Improvement of Cellular Structure and Mechanical Properties for Foam Injection Molding PP/EPDM Blend with Mica%云母粉对注塑发泡PP/EPDM共混物泡孔结构和力学性能的改善

    Institute of Scientific and Technical Information of China (English)

    谢敏讷; 黄汉雄

    2011-01-01

    采用注塑发泡方法制备了质量比为75/25的聚丙烯/三元乙丙橡胶(PP/EPDM)共混物和质量比为75/25/7.5的PP/EPDM/云母粉复合材料制品,分析了两种制品泡孔结构和结晶性能的差异及其对制品力学性能的影响.结果表明:与共混物发泡制品相比,复合材料发泡制品的拉伸屈服强度、拉伸断裂强度、断裂伸长率和无缺口冲击强度分别提高约5%、48%、206%和22%,并呈现应变硬化现象.复合材料发泡制品的泡孔直径明显较小且分布较均匀,泡孔密度明显较大,结晶度较高,这些是使复合材料发泡制品具有较高力学性能的主要原因.%Foamed polypropylene/ethylene-propylene-diene monomer ( PP/EPDM, 75/25, w/w ) blend and PP/EPDM/mica composite (75/25/7.5, w/w) were prepared via injection molding. The difference in the cellular structure and crystallization properties of both foamed parts and its effect on their mechanical properties were studied. The results showed that comparing with the foamed blend part, the foamed composite part exhibited an increase of 5% , 48% , 206% , and 22% in tensile yield strength, tensile facture strength, elongation at break and un-notched impact strength, respectively. Moreover, strain hardening appeared for the latter part. These results were attributed much smaller and more uniform cellular diameters, much larger cell density, and higher crystallinity of the foamed composite parts.

  18. Surface microstructure replication in injection molding

    DEFF Research Database (Denmark)

    Theilade, Uffe Arlø; Hansen, Hans Nørgaard

    2006-01-01

    In recent years, polymer components with surface microstructures have been in rising demand for applications such as lab-on-a-chip and optical components. Injection molding has proven to be a feasible and efficient way to manufacture such components. In injection molding, the mold surface topogra...

  19. Injection Molding of Plastics from Agricultural Materials

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharya, M.; Ruan, R.

    2001-02-22

    The objective of this research was to conduct a systematic study to relate injection molding parameters to properties of blends of starch and synthetic polymer. From this study, we wished to develop a thorough understanding of the injection molding process and gain significant insight into designing molds and aiding in developing products cheaply and efficiently.

  20. Planning an Injection Mold Design Training Program.

    Science.gov (United States)

    Allyn, Edward P.

    With the increased use of plastics worldwide the shortage of trained personnel in moldmaking and design for plastic injection molds is becoming critical. Local schools and community colleges should provide courses in mold design and mold making, since most workers presently learn while working under experienced designers on the job. Following this…

  1. Microbial Variants from Iron Ore Slimes: Mineral Specificity and pH Tolerance.

    Science.gov (United States)

    Abhilash; Ghosh, A; Pandey, B D; Sarkar, S

    2015-12-01

    This paper describes the isolation of the native bacterial strains from the iron ore mines slime pond and its extremophilic characteristics. The two microbial isolates designated as CNIOS-1 and CNIOS-2 were grown in selective silicate broth at pH 7.0 and the organisms were tested for their selective adhesion on silicate and alumina minerals. The silicate bacteria with their exopolymers are very potent to grow over aluminosilicates. It was established that CNIOS-1 grew preferentially in the presence of silicate mineral compared to CNIOS-2 which grew in the presence of alumina. The organisms were tested for growth at various pH and trials were carried to define their efficacy for eventual applications to remove gangue minerals of silica and alumina from the raw material.

  2. Is Mold the New Asbestos?

    Science.gov (United States)

    Colgan, Craig

    2003-01-01

    Mold and indoor air quality (IAQ) are matters of major concern to architects and their educational clients. The Environmental Protection Agency's Indoor Air Quality Tools for Schools program offers help to districts seeking to tackle IAQ issues. Strengthening community relations is one way to be ready in case of a bad environmental or IAQ report.…

  3. Stochastic resin transfer molding process

    CERN Document Server

    Park, M

    2016-01-01

    We consider one-dimensional and two-dimensional models of stochastic resin transfer molding process, which are formulated as random moving boundary problems. We study their properties, analytically in the one-dimensional case and numerically in the two-dimensional case. We show how variability of time to fill depends on correlation lengths and smoothness of a random permeability field.

  4. Hydrogen silsesquioxane mold coatings for improved replication of nanopatterns by injection molding

    OpenAIRE

    Hobæk, Thor Christian; Matschuk, Maria; Kafka, Jan; Pranov, Henrik J.; Larsen, Niels Bent

    2015-01-01

    We demonstrate the replication of nanosized pillars in polymer (cyclic olefin copolymer) by injection molding using nanostructured thermally cured hydrogen silsesquioxane (HSQ) ceramic coatings on stainless steel mold inserts with mold nanostructures produced by a simple embossing process. At isothermal mold conditions, the average pillar height increases by up to 100% and a more uniform height distribution is observed compared to a traditional metal mold insert. Thermal heat transfer simulat...

  5. Two dephosphorylation pathways of inositol 1,4,5-trisphosphate in homogenates of the cellular slime mould Dictyostelium discoideum

    NARCIS (Netherlands)

    Lookeren Campagne, Michiel M. van; Erneux, Cristophe; Eijk, Ronald van; Haastert, Peter J.M. van

    1988-01-01

    Dictyostelium discoideum homogenates contain phosphatase activity which rapidly dephosphorylates Ins(1,4,5)P3 (D-myo-inositol 1,4,5-trisphosphate) to Ins (myo-inositol). When assayed in Mg2+, Ins(1,4,5)P3 is dephosphorylated by the soluble Dictyostelium cell fraction to 20% Ins(1,4)P2 (D-myo-inosito

  6. Implementation of Molding Constraints in Topology Optimization

    DEFF Research Database (Denmark)

    Marx, S.; Kristensen, Anders Schmidt

    2009-01-01

    In many cases the topology optimization method yield inadmissible solutions in respect to a particular manufacturing process, e.g. injection molding. In the present work it is chosen to focus on the most common injection molding parameters/factors determining the quality of the mold geometry, i.......e. uniform thickness, filling of the die and ejection of the molded item, i.e. extrusion. The mentioned injection mold parameters/factors are introduced in the topology optimization by defining a centerline of the initial domain and then penalize elements in respect to the distance to the defined centerline...

  7. Precision injection molding of freeform optics

    Science.gov (United States)

    Fang, Fengzhou; Zhang, Nan; Zhang, Xiaodong

    2016-08-01

    Precision injection molding is the most efficient mass production technology for manufacturing plastic optics. Applications of plastic optics in field of imaging, illumination, and concentration demonstrate a variety of complex surface forms, developing from conventional plano and spherical surfaces to aspheric and freeform surfaces. It requires high optical quality with high form accuracy and lower residual stresses, which challenges both optical tool inserts machining and precision injection molding process. The present paper reviews recent progress in mold tool machining and precision injection molding, with more emphasis on precision injection molding. The challenges and future development trend are also discussed.

  8. A Comparative Study of Electrolyte Flow and Slime Particle Transport in a Newly Designed Copper Electrolytic Cell and a Laboratory-Scale Conventional Electrolytic Cell

    Science.gov (United States)

    Zeng, Weizhi; Wang, Shijie; Free, Michael L.

    2016-08-01

    An innovative copper electrolytic cell was designed with its inlet at the cell top and its outlet near the cell bottom, in opposite to conventional electrolytic cells. It was modeled in COMSOL Multiphysics to simulate copper electrorefining process. Unlike conventional electrorefining cells, downward electrolyte flows are more dominant in the fluid flow field in this cell, which leads to faster settlement of slime particles and less contamination to the cathode. Copper concentration profiles, electrolyte flow velocity field, slime particle movements, and slime particle distributions were obtained as simulation results, which were compared with those in a laboratory-scale conventional electrolytic cell. Advantages of the newly designed electrolytic cell were found: copper ions are distributed more uniformly in the cell with a thinner diffusion layer near the cathode; stronger convection exists in the inter-electrode domain with dominant downward flows; and slime particles have larger possibilities to settle down and are less likely to reach the cathode.

  9. Silane based coating of aluminium mold

    DEFF Research Database (Denmark)

    2013-01-01

    comprising a chemically bonded monolayer of silane compounds on the at least one surface wherein the silane is a halogenated silane. The at least one surface coated with the anti-stiction coating may be configured to withstand an injection molding process at a pressure above 100 MPa. Furthermore, a mold......A method of preparing an aluminum mold for injection molding is provided, the method comprises the steps of providing an aluminum mold having a least one surface, subjecting the at least one surface to a gas or liquid phase silane to thereby form an anti-stiction coating, the anti-stiction coating...... having at least one closed cavity is provided, at least one surface of the at least one cavity being an aluminium surface coated with a silane based coating layer. The silane based anti-stiction coating improves the anti-stiction properties of the mold which may allow for molding and demolding...

  10. Numerical Analysis of Mold Deformation Including Plastic Melt Flow During Injection Molding

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Joon Tae; Lee, Bong-Kee [Chonnam National University, Gwangju (Korea, Republic of)

    2014-07-15

    In the present study, a numerical analysis of an injection molding process was conducted for predicting the mold deformation considering non-Newtonian flow, heat transfer, and structural behavior. The accurate prediction of mold deformation during the filling stage is important to successfully design and manufacture a precision injection mold. While the local mold deformation can be caused by various factors, a pressure induced by the polymer melt is considered to be one of the most significant ones. In this regard, the numerical simulation considering both the melt filling and the mold deformation was carried out. A mold core for a 2D axisymmetric center-gated disk was used for the demonstration of the present study. The flow behavior inside the mold cavity and temperature distribution were analyzed along with the core displacement. Also, a Taguchi method was employed to investigate the influence of the relevant parameters including flow velocity, mold core temperature, and melt temperature.

  11. Compression molding of aerogel microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Pekala, Richard W. (Pleasant Hill, CA); Hrubesh, Lawrence W. (Pleasanton, CA)

    1998-03-24

    An aerogel composite material produced by compression molding of aerogel microspheres (powders) mixed together with a small percentage of polymer binder to form monolithic shapes in a cost-effective manner. The aerogel composites are formed by mixing aerogel microspheres with a polymer binder, placing the mixture in a mold and heating under pressure, which results in a composite with a density of 50-800 kg/m.sup.3 (0.05-0.80 g/cc). The thermal conductivity of the thus formed aerogel composite is below that of air, but higher than the thermal conductivity of monolithic aerogels. The resulting aerogel composites are attractive for applications such as thermal insulation since fabrication thereof does not require large and expensive processing equipment. In addition to thermal insulation, the aerogel composites may be utilized for filtration, ICF target, double layer capacitors, and capacitive deionization.

  12. Compression molding of aerogel microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Pekala, R.W.; Hrubesh, L.W.

    1998-03-24

    An aerogel composite material produced by compression molding of aerogel microspheres (powders) mixed together with a small percentage of polymer binder to form monolithic shapes in a cost-effective manner is disclosed. The aerogel composites are formed by mixing aerogel microspheres with a polymer binder, placing the mixture in a mold and heating under pressure, which results in a composite with a density of 50--800 kg/m{sup 3} (0.05--0.80 g/cc). The thermal conductivity of the thus formed aerogel composite is below that of air, but higher than the thermal conductivity of monolithic aerogels. The resulting aerogel composites are attractive for applications such as thermal insulation since fabrication thereof does not require large and expensive processing equipment. In addition to thermal insulation, the aerogel composites may be utilized for filtration, ICF target, double layer capacitors, and capacitive deionization. 4 figs.

  13. Onychomycosis due to opportunistic molds*

    Science.gov (United States)

    Martínez-Herrera, Erick Obed; Arroyo-Camarena, Stefanie; Tejada-García, Diana Luz; Porras-López, Carlos Francisco; Arenas, Roberto

    2015-01-01

    BACKGROUND: Onychomycosis are caused by dermatophytes and Candida, but rarely by non- dermatophyte molds. These opportunistic agents are filamentous fungi found as soil and plant pathogens. OBJECTIVES: To determine the frequency of opportunistic molds in onychomycosis. METHODS: A retrospective analysis of 4,220 cases with onychomycosis, diagnosed in a 39-month period at the Institute of Dermatology and Skin surgery "Prof. Dr. Fernando A. Cordero C." in Guatemala City, and confirmed with a positive KOH test and culture. RESULTS: 32 cases (0.76%) of onychomycosis caused by opportunistic molds were confirmed. The most affected age group ranged from 41 to 65 years (15 patients, 46.9%) and females were more commonly affected (21 cases, 65.6%) than males. Lateral and distal subungual onychomycosis (OSD-L) was detected in 20 cases (62.5%). The microscopic examination with KOH showed filaments in 19 cases (59.4%), dermatophytoma in 9 cases (28.1%), spores in 2 cases (6.25%), and filaments and spores in 2 cases (6.25%). Etiologic agents: Aspergillus sp., 11 cases (34.4%); Scopulariopsis brevicaulis, 8 cases (25.0%); Cladosporium sp., 3 cases (9.4%); Acremonium sp., 2 cases (6.25%); Paecilomyces sp., 2 cases (6.25%); Tritirachium oryzae, 2 cases (6.25%); Fusarium sp., Phialophora sp., Rhizopus sp. and Alternaria alternate, 1 case (3.1%) each. CONCLUSIONS: We found onychomycosis by opportunistic molds in 0.76% of the cases and DLSO was present in 62.5%. The most frequent isolated etiological agents were: Aspergillus sp. and Scopulariopsis brevicaulis. PMID:26131862

  14. Gating of Permanent Molds for ALuminum Casting

    Energy Technology Data Exchange (ETDEWEB)

    David Schwam; John F. Wallace; Tom Engle; Qingming Chang

    2004-03-30

    This report summarizes a two-year project, DE-FC07-01ID13983 that concerns the gating of aluminum castings in permanent molds. The main goal of the project is to improve the quality of aluminum castings produced in permanent molds. The approach taken was determine how the vertical type gating systems used for permanent mold castings can be designed to fill the mold cavity with a minimum of damage to the quality of the resulting casting. It is evident that somewhat different systems are preferred for different shapes and sizes of aluminum castings. The main problems caused by improper gating are entrained aluminum oxide films and entrapped gas. The project highlights the characteristic features of gating systems used in permanent mold aluminum foundries and recommends gating procedures designed to avoid common defects. The study also provides direct evidence on the filling pattern and heat flow behavior in permanent mold castings.

  15. Effect of Functional Nano Channel Structures Different Widths on Injection Molding and Compression Molding Replication Capabilities

    DEFF Research Database (Denmark)

    Calaon, M.; Tosello, G.; Garnaes, J.

    The present study investigates the capabilities of the two employed processes, injection molding (IM) and injection compression molding (ICM) on replicating different channel cross sections. Statistical design of experiment was adopted to optimize replication quality of produced polymer parts wit...

  16. Porous media heat transfer for injection molding

    Energy Technology Data Exchange (ETDEWEB)

    Beer, Neil Reginald

    2016-05-31

    The cooling of injection molded plastic is targeted. Coolant flows into a porous medium disposed within an injection molding component via a porous medium inlet. The porous medium is thermally coupled to a mold cavity configured to receive injected liquid plastic. The porous medium beneficially allows for an increased rate of heat transfer from the injected liquid plastic to the coolant and provides additional structural support over a hollow cooling well. When the temperature of the injected liquid plastic falls below a solidifying temperature threshold, the molded component is ejected and collected.

  17. Two-gene phylogeny of bright-spored Myxomycetes (slime moulds, superorder Lucisporidia).

    Science.gov (United States)

    Fiore-Donno, Anna Maria; Clissmann, Fionn; Meyer, Marianne; Schnittler, Martin; Cavalier-Smith, Thomas

    2013-01-01

    Myxomycetes, or plasmodial slime-moulds, are one of the largest groups in phylum Amoebozoa. Nonetheless, only ∼10% are in the database for the small subunit (SSU) ribosomal RNA gene, the most widely used gene for phylogenetics and barcoding. Most sequences belong to dark-spored Myxomycetes (order Fuscisporida); the 318 species of superorder Lucisporidia (bright-spored) are represented by only eleven genuine sequences. To compensate for this, we provide 66 new sequences, 37 SSU rRNA and 29 elongation factor 1-alpha (EF-1α), for 82% of the genera of Lucisporidia. Phylogenetic analyses of single- and two-gene alignments produce congruent topologies and reveal both morphological characters that have been overemphasised and those that have been overlooked in past classifications. Both classical orders, Liceida and Trichiida, and several families and genera are para/polyphyletic; some previously unrecognised clades emerge. We discuss possible evolutionary pathways. Our study fills a gap in the phylogeny of Amoebozoa and provides an extensive SSU rRNA sequence reference database for environmental sampling and barcoding. We report a new group I intron insertion site for Myxomycetes in one Licea.

  18. Two-gene phylogeny of bright-spored Myxomycetes (slime moulds, superorder Lucisporidia.

    Directory of Open Access Journals (Sweden)

    Anna Maria Fiore-Donno

    Full Text Available Myxomycetes, or plasmodial slime-moulds, are one of the largest groups in phylum Amoebozoa. Nonetheless, only ∼10% are in the database for the small subunit (SSU ribosomal RNA gene, the most widely used gene for phylogenetics and barcoding. Most sequences belong to dark-spored Myxomycetes (order Fuscisporida; the 318 species of superorder Lucisporidia (bright-spored are represented by only eleven genuine sequences. To compensate for this, we provide 66 new sequences, 37 SSU rRNA and 29 elongation factor 1-alpha (EF-1α, for 82% of the genera of Lucisporidia. Phylogenetic analyses of single- and two-gene alignments produce congruent topologies and reveal both morphological characters that have been overemphasised and those that have been overlooked in past classifications. Both classical orders, Liceida and Trichiida, and several families and genera are para/polyphyletic; some previously unrecognised clades emerge. We discuss possible evolutionary pathways. Our study fills a gap in the phylogeny of Amoebozoa and provides an extensive SSU rRNA sequence reference database for environmental sampling and barcoding. We report a new group I intron insertion site for Myxomycetes in one Licea.

  19. Exploring slime mould diversity in high-altitude forests and grasslands by environmental RNA analysis.

    Science.gov (United States)

    Kamono, Akiko; Meyer, Marianne; Cavalier-Smith, Thomas; Fukui, Manabu; Fiore-Donno, Anna Maria

    2013-04-01

    In spite of the ecological importance of protists, very little data is available on their distribution in soil. This investigation is the first of its kind on what could be the major components of the soil protistan community, the Myxomycetes, or plasmodial slime-moulds, a monophyletic class in the phylum Amoebozoa. Myxomycetes have a complex life cycle culminating in the formation of mainly macroscopic fruiting bodies, highly variable in shape and colour, which can be found in every terrestrial biome. Despite their prevalence, they are paradoxically absent from environmental DNA sampling studies. We obtained myxomycete SSU rRNA gene sequences from soil-extracted RNAs using specific primers. Soil samples were collected in three mountain ranges (France, Scotland and Japan). Our study revealed an unexpectedly high diversity of dark-spored Myxomycetes, with the recovery of 74 phylotypes. Of these, 74% had < 98% identity with known sequences, showing a hidden diversity; there was little overlap between localities, implying biogeographical patterns. Few phylotypes were dominant and many were unique, consistent with the 'rare biosphere' phenomenon. Our study provides the first detailed insight into the community composition of this ecologically important group of protists, establishing means for future studies of their distribution, abundance and ecology.

  20. Analysis of optical properties in injection-molded and compression-molded optical lenses.

    Science.gov (United States)

    Wang, Chung Yen; Wang, Pei Jen

    2014-04-10

    Numerical mold-flow simulations and experimental measurements for injection-molded lenses have been investigated in form accuracy on a two-cavity mold with various process conditions. First, form profiles of the molded lenses have been measured together with the corresponding simulated mold-temperature distribution and displacement distribution of the lens in the z direction. A flow-through type layout of cooling channels has been devised for balance of mold-temperature distribution in mold cavities with various parametric distances for assessments in uniformity of temperature distribution. Finally, a compression-molding process is proposed for the post-process of birefringence relaxation as well as adequate form accuracy of lenses. In conclusion, optimization of process parameters to achieve good form accuracy in a multicavity mold with symmetric geometry but nonuniform cooling conditions is difficult. A good design of cooling channels plus optimized process conditions could provide uniform mold-temperature distribution so that molded lenses of good quality would be possible. Then, the profile deviation of lenses could be further compensated by profile geometry corrections. In conclusion, the post-compression-molding process could make birefringence-free plastic lenses with good form accuracy.

  1. Mold

    Science.gov (United States)

    ... all, may produce toxins or poisonous substances called mycotoxins that may cause effects in humans. Although there are many types of mycotoxins, aflatoxins are probably the best known and most ...

  2. Mechanical Properties of Injection Molded and Compression Molded Samples from Nature-Butadiene Rubber

    Directory of Open Access Journals (Sweden)

    Skrobak Adam

    2016-01-01

    Full Text Available The aim of this paper is to show what extent there is an impact on the mechanical properties (tensile strength and tear strength of a standardized testing sample made of rubber compound based on nature rubber and butadiene rubber produced by injection molding in comparison with a sample produced by classic preparation (cutting out a compression molded plate according to the standard ISO 23529. For realization of this study it was necessary to design and produce an injection mold for all types testing samples. Subsequently, mechanical properties such as the tensile stress-strain and tear strenght of compression molded samples and injection molded samples were studied, compared and discussed.

  3. Nonlinear Modeling of a High Precision Servo Injection Molding Machine Including Novel Molding Approach

    Institute of Scientific and Technical Information of China (English)

    何雪松; 王旭永; 冯正进; 章志新; 杨钦廉

    2003-01-01

    A nonlinear mathematical model of the injection molding process for electrohydraulic servo injection molding machine (IMM) is developed.It was found necessary to consider the characteristics of asymmetric cylinder for electrohydraulic servo IMM.The model is based on the dynamics of the machine including servo valve,asymmetric cylinder and screw,and the non-Newtonian flow behavior of polymer melt in injection molding is also considered.The performance of the model was evaluated based on novel approach of molding - injection and compress molding,and the results of simulation and experimental data demonstrate the effectiveness of the model.

  4. Cellular automata

    CERN Document Server

    Codd, E F

    1968-01-01

    Cellular Automata presents the fundamental principles of homogeneous cellular systems. This book discusses the possibility of biochemical computers with self-reproducing capability.Organized into eight chapters, this book begins with an overview of some theorems dealing with conditions under which universal computation and construction can be exhibited in cellular spaces. This text then presents a design for a machine embedded in a cellular space or a machine that can compute all computable functions and construct a replica of itself in any accessible and sufficiently large region of t

  5. The Thermal Distortion of a Funnel Mold

    Science.gov (United States)

    Hibbeler, Lance C.; Thomas, Brian G.; Schimmel, Ronald C.; Abbel, Gert

    2012-10-01

    This article investigates the thermal distortion of a funnel mold for continuous casting of thin slabs and explores the implications on taper and solidification of the steel shell. The three-dimensional mold temperatures are calculated using shell-mold heat flux and cooling water profiles that were calibrated with plant measurements. The thermal stresses and distorted shape of the mold are calculated with a detailed finite-element model of a symmetric fourth of the entire mold and waterbox assembly, and they are validated with plant thermocouple data and measurements of the wear of the narrow-face copper mold plates. The narrow-face mold distorts into the typical parabolic arc, and the wide face distorts into a "W" shape owing to the large variation in bolt stiffnesses. The thermal expansion of the wide face works against the applied narrow-face taper and funnel effects, so the effect of thermal distortion must be considered to accurately predict the ideal mold taper.

  6. Nanostructuring steel for injection molding tools

    DEFF Research Database (Denmark)

    Al-Azawi, A.; Smistrup, Kristian; Kristensen, Anders

    2014-01-01

    has been produced by injection molding with good structure transfer fidelity. Thus we have demonstrated that by utilizing well-established fabrication techniques, nanostructured steel shims that are used in injection molding, a technique that allows low cost mass fabrication of plastic items...

  7. Mold Remediation in Schools and Commercial Buildings.

    Science.gov (United States)

    Environmental Protection Agency, Washington, DC. Office of Radiation and Indoor Air.

    This document describes how to investigate and evaluate moisture and mold problems in educational facilities, and presents the key steps for implementing a remediation plan. A checklist is provided for conducting mold remediation efforts along with a resource list of helpful organizations and governmental agencies. Appendices contain a glossary,…

  8. The use of IR thermography to show the mold and part temperature evolution in injection molding

    Science.gov (United States)

    Bula, Karol; Różański, Leszek; Marciniak-Podsadna, Lidia; Wróbel, Dawid

    2016-12-01

    This study concerns the application of infrared camera for injection molding analysis by measuring temperatures of both injection molded parts and injection mold cavities in a function of injection cycles. The mold with two cavities, differing in thickness (1 and 3 mm), and a cold direct runner was used. Isotactic polypropylene homopolymer was utilized to produce parts. Mold temperature was set at 22°C and controlled by a water chiller. Five measuring points were determined: SP1, SP2 (placed in the 3 mm cavity), SP3, SP4 (located in the 1 mm cavity) and SP5 around an injection molding gate. Our investigations showed that the highest temperature is localized around SP2 point and the lowest at SP4. Also, it was proved that even after 62 injection molding cycles, temperatures of cavities were not stable, revealing their further increase with each cycle.

  9. The use of IR thermography to show the mold and part temperature evolution in injection molding

    Directory of Open Access Journals (Sweden)

    Bula Karol

    2016-12-01

    Full Text Available This study concerns the application of infrared camera for injection molding analysis by measuring temperatures of both injection molded parts and injection mold cavities in a function of injection cycles. The mold with two cavities, differing in thickness (1 and 3 mm, and a cold direct runner was used. Isotactic polypropylene homopolymer was utilized to produce parts. Mold temperature was set at 22°C and controlled by a water chiller. Five measuring points were determined: SP1, SP2 (placed in the 3 mm cavity, SP3, SP4 (located in the 1 mm cavity and SP5 around an injection molding gate. Our investigations showed that the highest temperature is localized around SP2 point and the lowest at SP4. Also, it was proved that even after 62 injection molding cycles, temperatures of cavities were not stable, revealing their further increase with each cycle.

  10. IC chip stress during plastic package molding

    Energy Technology Data Exchange (ETDEWEB)

    Palmer, D.W.; Benson, D.A.; Peterson, D.W.; Sweet, J.N.

    1998-02-01

    Approximately 95% of the world`s integrated chips are packaged using a hot, high pressure transfer molding process. The stress created by the flow of silica powder loaded epoxy can displace the fine bonding wires and can even distort the metalization patterns under the protective chip passivation layer. In this study the authors developed a technique to measure the mechanical stress over the surface of an integrated circuit during the molding process. A CMOS test chip with 25 diffused resistor stress sensors was applied to a commercial lead frame. Both compression and shear stresses were measured at all 25 locations on the surface of the chip every 50 milliseconds during molding. These measurements have a fine time and stress resolution which should allow comparison with computer simulation of the molding process, thus allowing optimization of both the manufacturing process and mold geometry.

  11. Mold Simulator Study of the Initial Solidification of Molten Steel in Continuous Casting Mold: Part II. Effects of Mold Oscillation and Mold Level Fluctuation

    Science.gov (United States)

    Zhang, Haihui; Wang, Wanlin

    2016-04-01

    The surface quality of the continuous casting strands is closely related to the initial solidification of liquid steel in the vicinity of the mold meniscus, and thus the clear understanding of the behavior of molten steel initial solidification would be of great importance for the control of the quality of final slab. With the development of the mold simulator techniques, the complex interrelationship between the solidified shell surface profile, heat flux, shell thickness, mold level fluctuation, and the infiltrated slag film was well illustrated in our previous study. As the second part, this article investigated the effect of the mold oscillation frequency, stroke, and mold level fluctuation on the initial solidification of the molten steel through the conduction of five different experiments. Results suggested that in the case of the stable mold level, the oscillation marks (OMs) exhibit equally spaced horizon depressions on the shell surface, where the heat flux at the meniscus area raises rapidly during negative strip time (NST) period and the presence of each OMs on the shell surface is corresponding to a peak value of the heat flux variation rate. Otherwise, the shell surface is poorly defined by the existence of wave-type defects, such as ripples or deep depressions, and the heat flux variation is irregular during NST period. The rising of the mold level leads to the longer-pitch and deeper OMs formation; conversely, the falling of mold level introduces shorter-pitch and shallower OMs. With the increase of the mold oscillation frequency, the average value of the low-frequency heat flux at the meniscus increases; however, it decreases when the mold oscillation stroke increases. Additionally, the variation amplitude of the high-frequency temperature and the high-frequency heat flux decreases with the increase of the oscillation frequency and the reduction of the oscillation stroke.

  12. Experimental Studies of the Effects of Anode Composition and Process Parameters on Anode Slime Adhesion and Cathode Copper Purity by Performing Copper Electrorefining in a Pilot-Scale Cell

    Science.gov (United States)

    Zeng, Weizhi; Wang, Shijie; Free, Michael L.

    2016-10-01

    Copper electrorefining tests were conducted in a pilot-scale cell under commercial tankhouse environment to study the effects of anode compositions, current density, cathode blank width, and flow rate on anode slime behavior and cathode copper purity. Three different types of anodes (high, mid, and low impurity levels) were used in the tests and were analyzed under SEM/EDS. The harvested copper cathodes were weighed and analyzed for impurities concentrations using DC Arc. The adhered slimes and released slimes were collected, weighed, and analyzed for compositions using ICP. It was shown that the lead-to-arsenic ratio in the anodes affects the sintering and coalescence of slime particles. High current density condition can improve anode slime adhesion and cathode purity by intensifying slime particles' coalescence and dissolving part of the particles. Wide cathode blanks can raise the anodic current densities significantly and result in massive release of large slime particle aggregates, which are not likely to contaminate the cathode copper. Low flow rate can cause anode passivation and increase local temperatures in front of the anode, which leads to very intense sintering and coalescence of slime particles. The results and analyses of the tests present potential solutions for industrial copper electrorefining process.

  13. Thermoplastic blow molding of metals

    Directory of Open Access Journals (Sweden)

    Jan Schroers

    2011-01-01

    Full Text Available While plastics have revolutionized industrial design due to their versatile processability, their relatively low strength has hampered their use in structural components. On the other hand, while metals are the basis for strong structural components, the geometries into which they can be processed are rather limited. The “ideal” material would offer a desirable combination of superior structural properties and the ability to be precision (net shaped into complex geometries. Here we show that bulk metallic glasses (BMGs, which have superior mechanical properties, can be blow molded like plastics. The key to the enhanced processability of BMG formers is their amenability to thermoplastic forming. This allows complex BMG structures, some of which cannot be produced using any other metal process, to be net shaped precisely.

  14. Challenges in mold manufacturing for high precision molded diffractive optical elements

    Science.gov (United States)

    Pongs, Guido; Bresseler, Bernd; Schweizer, Klaus; Bergs, Thomas

    2016-09-01

    Isothermal precision glass molding of imaging optics is the key technology for mass production of precise optical elements. Especially for numerous consumer applications (e.g. digital cameras, smart phones, …), high precision glass molding is applied for the manufacturing of aspherical lenses. The usage of diffractive optical elements (DOEs) can help to further reduce the number of lenses in the optical systems which will lead to a reduced weight of hand-held optical devices. But today the application of molded glass DOEs is limited due to the technological challenges in structuring the mold surfaces. Depending on the application submicrometer structures are required on the mold surface. Furthermore these structures have to be replicated very precisely to the glass lens surface. Especially the micro structuring of hard and brittle mold materials such as Tungsten Carbide is very difficult and not established. Thus a multitude of innovative approaches using diffractive optical elements cannot be realized. Aixtooling has investigated in different mold materials and different suitable machining technologies for the micro- and sub-micrometer structuring of mold surfaces. The focus of the work lays on ultra-precision grinding to generate the diffractive pattern on the mold surfaces. This paper presents the latest achievements in diffractive structuring of Tungsten Carbide mold surfaces by ultra-precision grinding.

  15. Characterization of fiberglass-filled diallyl phthalate plastic molding resins and molded parts

    Energy Technology Data Exchange (ETDEWEB)

    Whitaker, R.B.; Glaub, J.E.; Bonekowski, N.R.; Gillham, P.D.

    1980-12-01

    Characterization of diallyl phthalate (DAP) molding resins was undertaken by differential scanning calorimetry (DSC) and by combined size exclusion chromatography (SEC)/low angle laser light scattering (LALLS) in order to better predict moldability and storage life limits. Completeness of cure of molded parts, before and after any post-curing, was also determined by thermal analysis. Molecular weights and molecular weight distributions of the DAP molding resins by SEC/LALLS indicated that the better molding resins have lower M/sub w//M/sub n/ ratios. Association effects were observed, which could not be overcome by solvent modification alone. Determination of DAP molding resin heats of reaction by DSC indicated a linear relation between ..delta..H/sub R/ and weight percent filler for the good molding resins. DSC analyses of molded DAP parts showed that 95% cure was achieved in some as-molded parts, with a post-cure temperature of 165/sup 0/C being required to complete the cure to 100%. Thickness of the parts was a factor, with the thicker parts being 100% cured as molded. The glass transition temperature (T/sub g/) of the molded parts increased as cure was completed, to approx. 160 to 165/sup 0/C maximum. These results are consistent with a model of thermoset resin curing behavior which states that 100% cure can be achieved only if a post-curing operation is conducted above the T/sub g infinity/ (T/sub g/ at complete cure) of the polymer.

  16. Cooling simulation of plastic injection molding

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Analyses the cooling of mold and plastic part during injectionmolding and the continued cooling of plastic part after being ejected from mold using the heat transfer theory and Boundary Element Method (BEM) to predict the temperature distribution in both mold and plastic part,and presents the experiments carried out with plates of ABS (Acrylonitrile-Butadiene-Styrene) to verify the validity of the cooling analysis software used to simulate the temperature distribution in ABS plate parts, and concludes that the analysis software agree qualitatively well with actual experimental findings.

  17. Electrical and dielectric properties of foam injection-molded polypropylene/multiwalled carbon nanotube composites

    Science.gov (United States)

    Ameli, A.; Nofar, M.; Saniei, M.; Hossieny, N.; Park, C. B.; Pötschke, P.

    2015-05-01

    A combination of high dielectric permittivity (ɛ') and low dielectric loss (tan δ) is required for charge storage applications. In percolative systems such as conductive polymer composites, however, obtaining high ɛ' and low tan δ is very challenging due to the sharp insulation-conduction transition near the threshold region. Due to the particular arrangement of conductive fillers induced by both foaming and injection molding processes, they may address this issue. Therefore, this work evaluates the application of foam injection molding process in fabricating polymer nanocomposites for energy storage. Polypropylene-multiwalled carbon nanotubes (PP-MWCNT) composites were prepared by melt mixing and foamed in an injection molding process. Electrical conductivity (σ), ɛ' and tan δ were then characterized. Also, scanning and transmission electron microscopy (SEM and TEM) was used to investigate the carbon nanotube's arrangement as well as cellular morphology. The results showed that foam injection-molded composites exhibited highly superior dielectric properties to those of solid counterparts. For instance, foamed samples had ɛ'=68.3 and tan δ =0.05 (at 1.25 vol.% MWCNT), as opposed to ɛ'=17.8 and tan δ=0.04 in solid samples (at 2.56 vol.% MWCNT). The results of this work reveal that high performance dielectric nanocomposites can be developed using foam injection molding technologies for charge storage applications.

  18. Electrical and dielectric properties of foam injection-molded polypropylene/multiwalled carbon nanotube composites

    Energy Technology Data Exchange (ETDEWEB)

    Ameli, A.; Nofar, M.; Saniei, M.; Hossieny, N.; Park, C. B. [Microcellular Plastics Manufacturing Laboratory, Department of Mechanical and Industrial Engineering, University of Toronto, 5 King’s College Road, Toronto, Ontario, Canada M5S 3G8 (Canada); Pötschke, P. [Leibniz-Institut für Polymerforschung Dresden e.V. (IPF), Hohe Strasse 6, D-01069 Dresden (Germany)

    2015-05-22

    A combination of high dielectric permittivity (ε′) and low dielectric loss (tan δ) is required for charge storage applications. In percolative systems such as conductive polymer composites, however, obtaining high ε′ and low tan δ is very challenging due to the sharp insulation-conduction transition near the threshold region. Due to the particular arrangement of conductive fillers induced by both foaming and injection molding processes, they may address this issue. Therefore, this work evaluates the application of foam injection molding process in fabricating polymer nanocomposites for energy storage. Polypropylene-multiwalled carbon nanotubes (PP-MWCNT) composites were prepared by melt mixing and foamed in an injection molding process. Electrical conductivity (σ), ε′ and tan δ were then characterized. Also, scanning and transmission electron microscopy (SEM and TEM) was used to investigate the carbon nanotube’s arrangement as well as cellular morphology. The results showed that foam injection-molded composites exhibited highly superior dielectric properties to those of solid counterparts. For instance, foamed samples had ε′=68.3 and tan δ =0.05 (at 1.25 vol.% MWCNT), as opposed to ε′=17.8 and tan δ=0.04 in solid samples (at 2.56 vol.% MWCNT). The results of this work reveal that high performance dielectric nanocomposites can be developed using foam injection molding technologies for charge storage applications.

  19. Fast prototyping of injection molded polymer microfluidic chips

    DEFF Research Database (Denmark)

    Hansen, Thomas Steen; Selmeczi, David; Larsen, Niels Bent

    2010-01-01

    We present fast prototyping of injection molding tools by the definition of microfluidic structures in a light-curable epoxy (SU-8) directly on planar nickel mold inserts. Optimized prototype mold structures could withstand injection molding of more than 300 replicas in cyclic olefin copolymer (COC...

  20. Evaluation of stability for monolayer injection molding tools coating

    DEFF Research Database (Denmark)

    Cech, Jiri; Taboryski, Rafael J.

    2012-01-01

    We tested and characterized molecular coating of Aluminium and Nickel prototype molds and mold inserts for polymer replication via injection molding (IM). X-Ray photoelectron spectroscopy (XPS) data, sessile drop contact angles with multiple fluids, surface energy and roughness data have been...... and especially suitable for rapid prototyping and mold geometry testing....

  1. Processing integral-skin polyolefin foams in single-charge rotational foam molding

    Science.gov (United States)

    Pop-Iliev, Remon

    This thesis focuses on establishing the scientific and engineering foundations for gaining a fundamental understanding of the mechanisms and critical parameters governing the processing of integral-skin low-density polyolefin foams in rotational foam molding. The presented research is particularly intended to broaden the knowledge in the field of manufacturing adjacent, but clearly distinct, layers of non-cellular and cellular structures, consisting of identical or compatible plastic grades, using a single-charge processing concept. Although this technology is beneficial for the efficacy of the molding process and the structural homogeneity of the moldings, its optimization raised a fairly large number of fundamental issues that had to be resolved through further research. In this context, an attempt has been made to establish rigorous, experimentally validated, theoretical models that describe the phenomena identified as the fundamental challenges of this technology. The major contributions of this thesis include: (i) optimization of the single-charge rotational foam molding process for the manufacture of both PE/PE and PE/PP integral-skin cellular composites, (ii) development of a two-step oven temperature profile that prevents the foamable resins invading the solid skin layer and ensures that skin formation always completes prior to the activation of the foamable resin, (iii) fundamental study of the adherence behavior of powders and foamable pellets to a high-temperature rotating mold wall, (iv) fundamental study of the lifespan of CBA-blown bubbles in non-pressurized non-isothermal polymer melts using hot-stage optical microscopy and digital imaging, (v) development of a detailed theoretical model involving diffusion, surface tension, and viscosity to simulate the observed foaming mechanism, and (vi) fundamental study of the rotofoamablility of polyolefin resins using both dry blending and melt compounding based methods and characterization of rheological and

  2. Bio-Imitation of Mexican Migration Routes to the USA with Slime Mould on 3D Terrains

    Institute of Scientific and Technical Information of China (English)

    Andrew Adamatzky; Genaro J Martinez

    2013-01-01

    Plasmodium ofPhysarum polycephalum (P.polycephalum) is a large single cell visible by an unaided eye.It shows sophisticated behavioural traits in foraging for nutrients and developing an optimal transport network of protoplasmic tubes spanning sources of nutrients.When placed in an environment with distributed sources of nutrients the cell ‘computes’ an optimal graph spanning the nutrients by growing a network of protoplasmic tubes.P.polycephalum imitates development of man-made transport networks of a country when configuration of nutrients represents major urban areas.We employed this feature of the slime mould to imitate mexican migration to USA.The Mexican migration to USA is the World's largest migration system.We bio-physically imitated the migration using slime mould P.polycephalum.In laboratory experiments with 3D Nylon terrains of USA we imitated development of migratory routes from Mexico-USA border to ten urban areas with high concentration of Mexican migrants.From results of laboratory experiments we extracted topologies of migratory routes,and high-lighted a role of elevations in shaping the human movement networks.

  3. Solving depressions formed during production of plastic molding

    Directory of Open Access Journals (Sweden)

    J. Dobránsky

    2015-07-01

    Full Text Available This article deals with improvement of design properties of molded plastic parts. It can be achieved by modifying construction of metal injection mold and optimization of parameters in injection process. The subject of our examination was depressions formed on molded plastic parts which are inacceptable in the process of approval. The problem which has arisen was solved in two phases. The first phase consisted in alteration of injection mold design – enlargement of injection molding gate. In the second phase, we have changed the location of injection molding gate. After performing constructional modifications, new molded plastic parts were manufactured and assessed.

  4. Modelling Morphogenesis: From Single Cells to Crawling Slugs

    NARCIS (Netherlands)

    Savill, N.J.; Hogeweg, P.

    2002-01-01

    We present a three-dimensional hybrid cellular automata (CA)/partial differential equation (PDE) model that allows for the study of morphogenesis in simple cellular systems. We apply the model to the cellular slime mold Dictyostelium discoideum "from single cells to crawling slug". Using simple loca

  5. A new insight into foaming mechanisms in injection molding via a novel visualization mold

    Directory of Open Access Journals (Sweden)

    V. Shaayegan

    2016-06-01

    Full Text Available The complex mechanisms of bubble nucleation and dynamics in foam injection molding have not been uncovered despite many previous efforts due to the non-steady stop-and-flow nature of injection molding and the non-uniform temperature and pressure distributions in the mold. To this end, a new visualization mold was designed and manufactured for the direct observation of bubble nucleation and growth/collapse in foam injection molding. A reflective prism was incorporated into the stationary part of the injection mold with which the nucleation and growth behaviors of bubbles were successfully observed. The mechanisms of bubble nucleation in low- and high-pressure foam injection molding, with and without the application of gas-counter pressure, was investigated. We identified how the inherently non-uniform cell structure is developed in low-pressure foam injection molding with gate-nucleated bubbles, and when and how cell nucleation occurs in high-pressure foam injection molding with a more uniform pressure drop.

  6. Custom molded thermal MRg-FUS phantom

    Science.gov (United States)

    Eames, Matthew D. C.; Snell, John W.; Hananel, Arik; Kassell, Neal F.

    2012-11-01

    This article describes a method for creating custom-molded thermal phantoms for use with MR-guided focused ultrasound systems. The method is defined here for intracranial applications, though it may be modified for other anatomical targets.

  7. Rozen : steeds meer bekend over Black Mold

    NARCIS (Netherlands)

    Smits, A.P.; Kohrman, E.

    2009-01-01

    Onderzoek naar Black Mold heeft al veel informatie opgeleverd over de verspreiding, bestrijding en ontwikkeling van de oculatieschimmel. In dit artikel de nieuwste resultaten van PPO en Cultus Agro Advies

  8. Three-Dimensional Pneumatic Molding of Veneers

    Directory of Open Access Journals (Sweden)

    Milan Gaff

    2014-07-01

    Full Text Available The goal of this paper is to introduce a new testing method suitable for the evaluation of the three-dimensional (3-D moldability of veneers and to use this method to test the impact of specific factors on the 3-D pneumatic molding process. The tested factors included veneer moisture content, wood species, shape of test piece, and fixing method on the maximum wood deflection. Veneers were molded using compressed air on equipment designed by our group for the sole purpose of this experiment. The results indicated that the monitored factors had an effect on deflection during the 3-D molding process. The results of this investigation extend the state-of-the-art knowledge regarding this technology and indicate the possibility of utilizing this innovative testing method for 3-D molded veneers.

  9. Injection molded optical backplane for broadcast architecture

    Science.gov (United States)

    Rosenberg, Paul; Mathai, Sagi; Sorin, Wayne V.; McLaren, Moray; Straznicky, Joseph; Panotopoulos, Georgios; Warren, David; Morris, Terry; Tan, Michael R. T.

    2012-01-01

    A low cost, blind mate, injection molded optical backplane is presented. The optical backplane is comprised of 12 channel optical broadcast buses, operating at 10Gbps/channel with six blindmate optical output ports spaced 1U apart.

  10. Molds on Food: Are They Dangerous?

    Science.gov (United States)

    ... green dots on bread, white dust on Cheddar, coin-size velvety circles on fruits, and furry growth ... below the surface. Moldy foods may also have bacteria growing along with the mold. Hard salami and ...

  11. National Allergy Bureau Pollen and Mold Report

    Science.gov (United States)

    ... the Expert Search Search AAAAI National Allergy Bureau Pollen and Mold Report Date: April 11, 2017 Location: ... 11, 2017 Click Here to View Most Recent Pollen and Spore Levels (04/10/2017) If you ...

  12. 21 CFR 133.184 - Roquefort cheese, sheep's milk blue-mold, and blue-mold cheese from sheep's milk.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Roquefort cheese, sheep's milk blue-mold, and blue-mold cheese from sheep's milk. 133.184 Section 133.184 Food and Drugs FOOD AND DRUG ADMINISTRATION..., sheep's milk blue-mold, and blue-mold cheese from sheep's milk. (a) Description. (1) Roquefort...

  13. Die Casting Mold Design for Aluminum Alloy Shell of Instrument

    Directory of Open Access Journals (Sweden)

    Li Yuanyuan

    2015-01-01

    Full Text Available This paper is about die casting mold design for aluminum alloy shell of instrument. Three-dimensional model of the casting and mold are designed by using Pro/Engineer and AutoCad which can analyze forming quality. Digital design and theoretical calculation can greatly shorten product development cycle and mold design cycle, improve the accuracy of product design and mold design, and reduce the cost of mold design.

  14. Integrated mold/surface-micromachining process

    Energy Technology Data Exchange (ETDEWEB)

    Barron, C.C.; Fleming, J.G.; Montague, S.; Sniegowski, J.J.; Hetherington, D.L.

    1996-03-01

    We detail a new monolithically integrated silicon mold/surface-micromachining process which makes possible the fabrication of stiff, high-aspect-ratio micromachined structures integrated with finely detailed, compliant structures. An important example, which we use here as our process demonstration vehicle, is that of an accelerometer with a large proof mass and compliant suspension. The proof mass is formed by etching a mold into the silicon substrate, lining the mold with oxide, filling it with mechanical polysilicon, and then planarizing back to the level of the substrate. The resulting molded structure is recessed into the substrate, forming a planar surface ideal for subsequent processing. We then add surface-micromachined springs and sense contacts. The principal advantage of this new monolithically integrated mold/surface-micromachining process is that it decouples the design of the different sections of the device: In the case of a sensitive accelerometer, it allows us to optimize independently the proof mass, which needs to be as large, stiff, and heavy as possible, and the suspension, which needs to be as delicate and compliant as possible. The fact that the high-aspect-ratio section of the device is embedded in the substrate enables the monolithic integration of high-aspect-ratio parts with surface-micromachined mechanical parts, and, in the future, also electronics. We anticipate that such an integrated mold/surface micromachining/electronics process will offer versatile high-aspect-ratio micromachined structures that can be batch-fabricated and monolithically integrated into complex microelectromechanical systems.

  15. Cellular Telephone

    Institute of Scientific and Technical Information of China (English)

    杨周

    1996-01-01

    Cellular phones, used in automobiles, airliners, and passenger trains, are basically low-power radiotelephones. Calls go through radio transmitters that are located within small geographical units called cells. Because each cell’s signals are too weak to interfere with those of other cells operating on the same fre-

  16. Fast Mold Temperature Evolution on Micro Features Replication Quality during Injection Molding

    DEFF Research Database (Denmark)

    Liparoti, S.; Calaon, Matteo; Speranza, V.;

    2016-01-01

    lithography and subsequent nickel electroplating. The mold temperature was controlled by a thin heating device (composed by polyimide as insulating layer and polyimide carbon black loaded aselectrical conductive layer) able to increase the temperature on mold surface in a few seconds (40°C/s) by Joule effect...

  17. Development of sheet molding compound solar collectors with molded-in silvered glass reflective surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Champion, R. L.; Allred, R. E.

    1980-12-01

    The reflecting concentrator of a parabolic trough solar collector system comprises approximately 40% of initial system cost. The parabolic concentrator structure is also the most influential component in determining overall system efficiency. Parabolic test moldings have been fabricated from a general purpose sheet molding compound with flat chemically strengthened glass, flat annealed glass, and thermally formed glass. The test panel configuration was a 1.22 m x 0.61 m, 45/sup 0/ rim angle (0.762 m focal length) parabola. Attempts to mold with annealed sheet glass (1 mm thick) and thermally formed glass (1.25 mm thick) were unsuccessful; only the chemically strengthened glass (1.25 mm thick) was strong enough to survive molding pressures. Because of the mismatch in thermal expansion between glass and sheet molding compound, the as-molded panels contained a sizeable residual stress. The results are given of dimensional changes taking place in the panels under accelerated thermal cycling and outdoor aging conditions; these results are compared to an analytical model of the laminate. In addition, the sheet molding compound has been examined for thermomechanical properties and flow behavior in the rib sections. Results indicated that lowering the thermal expansion coefficient of the sheet molding compound through material modifications would produce a more stable structure.

  18. Microcellular foam injection molding with cellulose nanofibers (CNFs)

    Science.gov (United States)

    Ohshima, Masahiro; Kubota, Masaya; Ishihara, Shota; Hikima, Yuta; Sato, Akihiro; Sekiguchi, Takafumi

    2016-03-01

    Cellulose nanofibers (CNFs) nanocomposites polypropylene foams are prepared by microcellular foam injection molding with core-back operation. The modified CNFs were blended with isotactic-polypropylene (i-PP) at different CNFs weight percentages and foamed to investigate the effect of CNFs on cell morphology. CNFs in i-PP increased the elastic modulus and induced a strain hardening behavior. CNFs also shifted the crystallization temperature of i-PP to higher temperature and enhanced crystallization. With these changes in rheological and thermal properties, CNFs could reduce the cell size and increase the cell density of the foams. By adjusting the core-back timing i.e., foaming temperature, the closed cell and the nano-fibrillated open cellular structure could be produced. The flexural modulus and bending strength of foams were measured by three point flexural tester. The flexural modulus and bending strength were increased as the CNFs content in i-PP was increased at any foam expansion ratio.

  19. Effects of mold geometry on fiber orientation of powder injection molded metal matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, Faiz, E-mail: faizahmad@petronas.com.my; Aslam, Muhammad, E-mail: klaira73@gmail.com; Altaf, Khurram, E-mail: khurram.altaf@petronas.com.my; Shirazi, Irfan, E-mail: irfanshirazi@hotmail.com [Mechanical Engineering Universiti Teknologi PETRONAS Malaysia (Malaysia)

    2015-07-22

    Fiber orientations in metal matrix composites have significant effect on improving tensile properties. Control of fiber orientations in metal injection molded metal composites is a difficult task. In this study, two mold cavities of dimensions 6x6x90 mm and 10x20x180 mm were used for comparison of fiber orientation in injection molded metal composites test parts. In both mold cavities, convergent and divergent flows were developed by modifying the sprue dimensions. Scanning electron microscope (SEM) was used to examine the fiber orientations within the test samples. The results showed highly aligned fiber in injection molded test bars developed from the convergent melt flow. Random orientation of fibers was noted in the composites test bars produced from divergent melt flow.

  20. Study On The External Gas-Assisted Mold Temperature Control For Thin Wall Injection Molding

    Directory of Open Access Journals (Sweden)

    ThanhTrung Do

    2017-03-01

    Full Text Available Dynamic mold surface temperature control (DMTC has many advantages in micro-injection molding as well as thin-wall molding product. In this paper, DMTC will be applied for the thin-wall molding part with the observation of the weldline appearance and the weldline strength. The heating step of DMTC will be achieved by the hot air flow directly to the weldline area. The results show that the heating rate could be reached to 4.5C/s, which could raising the mold surface from 30C to over 120C within 15 s. The melt filling was operated with high temperature at the weldline area; therefore, the weldline appearance was eliminated. In addition, the weldline strength was also improved. The results show that the thinner part had the higher strength of the weldline

  1. Injection molding simulation with variothermal mold temperature control of highly filled polyphenylene sulfide

    Science.gov (United States)

    Birkholz, A.; Tschiersky, M.; Wortberg, J.

    2015-05-01

    For the installation of a fuel cell stack to convert chemical energy into electricity it is common to apply bipolar plates to separate and distribute reaction gases and cooling agents. For reducing manufacturing costs of bipolar plates a fully automated injection molding process is examined. The high performance thermoplastic matrix material, polyphenylene sulfide (PPS), defies against the chemical setting and the operation temperature up to 200 °C. To adjust also high electrical and thermal conductivity, PPS is highly filled with various carbon fillers up to an amount of 65 percentage by volume. In the first step two different structural plates (one-sided) with three different gate heights and molds are designed according to the characteristics of a bipolar plate. To cope with the approach that this plate should be producible on standard injection molding machines with variothermal mold temperature control, injection molding simulation is used. Additionally, the simulation should allow to formulate a quality prediction model, which is transferrable to bipolar plates. Obviously, the basis for a precise simulation output is an accurate description of the material properties and behavior of the highly filled compound. This, the design of the structural plate and mold and the optimization via simulation is presented, as well. The influence of the injection molding process parameters, e.g. injection time, cycle times, packing pressure, mold temperature, and melt temperature on the form filling have been simulated to determine optimal process conditions. With the aid of the simulation and the variothermal mold temperature control it was possible to reduce the required melt temperature below the decomposition temperature of PPS. Thereby, hazardous decomposition products as hydrogen sulfide are obviated. Thus, the health of the processor, the longevity of the injection molding machine as well as the material and product properties can be protected.

  2. Environmental impact estimation of mold making process

    Science.gov (United States)

    Kong, Daeyoung

    Increasing concern of environmental sustainability regarding depletion of natural resources and resulting negative environmental impact has triggered various movements to address these issues. Various regulations about product life cycle have been made and applied to industries. As a result, how to evaluate the environmental impact and how to improve current technologies has become an important issue to product developers. Molds and dies are very generally used manufacturing tools and indispensible parts to the production of many products. However, evaluating environmental impact in mold and die manufacturing is not well understood and not much accepted yet. The objective of this thesis is to provide an effective and straightforward way of environmental analysis for mold and die manufacturing practice. For this, current limitations of existing tools were identified. While conventional life cycle assessment tools provide a lot of life cycle inventories, reliable data is not sufficient for the mold and die manufacturer. Even with comprehensive data input, current LCA tools only provide another comprehensive result which is not directly applicable to problem solving. These issues are critical especially to the mold and die manufacturer with limited resource and time. This thesis addresses the issues based on understanding the needs of mold and die manufacturers. Computer aided manufacturing (CAM) is the most frequently used software tool and includes most manufacturing information including the process definition and sometimes geometric modeling. Another important usage of CAM software tools is problem identification by process simulation. Under the virtual environment, possible problems are detected and solved. Environmental impact can be handled in the same manner. To manufacture molds and dies with minimizing the associated environmental impact, possible environmental impact sources must be minimized before the execution in the virtual environment. Molds and dies

  3. Stability of FDTS monolayer coating on aluminum injection molding tools

    DEFF Research Database (Denmark)

    Cech, Jiri; Taboryski, Rafael J.

    2012-01-01

    The injection molding industry often employs prototype molds and mold inserts from melt spun (rapid solidification processing [1,2]) aluminum, especially for applications in optics [3,4], photonics [5] and microfludics. Prototypes are also used for verification of mold filling. The use of aluminum...... tools has reduced lead time (days instead of weeks) and manufacturing cost (30% of conventional mold). Moreover, for aluminum, a surface roughness (RMS) below 5 nm can be obtained with diamond machining [3,4,6]. Conventional mold coatings add cost and complexity, and coatings with thicknesses of a few...

  4. Injection molding of high aspect ratio sub-100 nm nanostructures

    DEFF Research Database (Denmark)

    Matschuk, Maria; Larsen, Niels B

    2013-01-01

    with FDTS. Reduced adhesion forces are consistent with lowered friction that reduces the risk of fracturing the nanoscopic pillars during demolding. Optimized mold surface chemistry and associated injection molding conditions permitted the fabrication of square arrays of 40 nm wide and 107 nm high (aspect......We have explored the use of mold coatings and optimized processing conditions to injection mold high aspect ratio nanostructures (height-to-width >1) in cyclic olefin copolymer (COC). Optimizing the molding parameters on uncoated nickel molds resulted in slight improvements in replication quality...

  5. 煤泥的浮选试验研究%Flotation experimental study of the coal slime

    Institute of Scientific and Technical Information of China (English)

    缪长勇; 郭喜民

    2012-01-01

    That article illustrates the advantages, and takes the coal slime from some company as an example, a research is conducted that makes coMParison between flotation column and flotation machine. Eventually the results show that the flotation column is more predominant in reducing the ash in clean coal and improving the efficiency of sizing coMParing to the flotation machines.%该文阐述了浮选柱的优点,并以某选煤厂煤泥为例,分别进行了浮选柱与浮选机的对比试验研究。结果表明:浮选柱在降低精煤灰分、提高分选效率方面,浮选柱比浮选机具有显著的优越性。

  6. Study on the Efficient Coal Slime Flotation%煤泥高效浮选技术研究

    Institute of Scientific and Technical Information of China (English)

    孙青; 谢华

    2011-01-01

    This article introduces the approaches of reducing production costs and improving the economic efficiency during the coal slime flotation process; focuses on the methods of increasing the output of clean coal and reducing the ash of clean coal and consumption of reagent. It has some reference value on transformation and production of coal preparation plant to improve quality and reduce consumption.%介绍了煤泥浮选过程中,降低生产成本、提高经济效益的途径;重点探讨了提高精煤产量、降低精煤灰分及减少药剂消耗的方法。对选煤厂改造及生产中提质降耗有一定的参考意义。

  7. Gating of Permanent Molds for Aluminum Casting

    Energy Technology Data Exchange (ETDEWEB)

    David Schwam; John F. Wallace; Tom Engle; Qingming Chang

    2004-01-01

    This report summarizes a two-year project, DE-FC07-011D13983 that concerns the gating of aluminum castings in permanent molds. The main goal of the project is to improve the quality of aluminum castings produced in permanent molds. The approach taken was to determine how the vertical type gating systems used for permanent mold castings can be designed to fill the mold cavity with a minimum of damage to the quality of the resulting casting. It is evident that somewhat different systems are preferred for different shapes and sizes of aluminum castings. The main problems caused by improper gating are entrained aluminum oxide films and entrapped gas. The project highlights the characteristic features of gating systems used in permanent mold aluminum foundries and recommends gating procedures designed to avoid common defects. The study also provides direct evidence on the filling pattern and heat flow behavior in permanent mold castings. Equipment and procedure for real time X-Ray radiography of molten aluminum flow into permanent molds have been developed. Other studies have been conducted using water flow and behavior of liquid aluminum in sand mold using real time photography. This investigation utilizes graphite molds transparent to X-Rays making it possible to observe the flow pattern through a number of vertically oriented grating systems. These have included systems that are choked at the base of a rounded vertical sprue and vertical gating systems with a variety of different ingates into the bottom of a mold cavity. These systems have also been changed to include gating systems with vertical and horizontal gate configurations. Several conclusions can be derived from this study. A sprue-well, as designed in these experiments, does not eliminate the vena contracta. Because of the swirling at the sprue-base, the circulating metal begins to push the entering metal stream toward the open runner mitigating the intended effect of the sprue-well. Improved designs of

  8. Modelling and monitoring in injection molding

    DEFF Research Database (Denmark)

    Thyregod, Peter

    2001-01-01

    -conforning unit is only expected very rarely during sampling, a moving sum chart and a CUSUM chart are equivalent. Finally, the correlation structure of 21 process variables has been studied prior to monitoring the process. Is is illustrated how the process can be analysed with multivariate techniques......This thesis is concerned with the application of statistical methods in quality improvement of injection molded parts. The methods described are illustrated with data from the manufacturing of parts for a medical device. The emphasis has been on the variation between cavities in multi-cavity molds...... taken within the same machine set-point did not cause great variation compared to the two preceding sources of variation. A simple graphical approach is suggested for finding patterns in the cavity differences. Applying this method to data from a 16 cavity mold, a clear connection was found between...

  9. Double blind placebo controlled exposure to molds

    DEFF Research Database (Denmark)

    Meyer, H W; Jensen, K A; Nielsen, K F

    2005-01-01

    non-significant, and at the same level as after placebo exposure. The developed exposure system based on the Particle-Field and Laboratory Emission Cell (P-FLEC) makes it possible to deliver a precise and highly controlled dose of mold spores from water-damaged building materials, imitating realistic....... In conclusion this is, to our knowledge, the first study to successfully conduct a human exposure to a highly controlled dose of fungal material aerosolized directly from wet building materials. This short-term exposure to high concentrations of two different molds induced no more reactions than exposure...... to placebo in eight sensitive school employees. However, a statistical type II error cannot be excluded because of the small sample size. PRACTICAL IMPLICATIONS: In this double blind, placebo controlled study of mold exposure changes in symptoms, objective measurements and blood samples were small and mostly...

  10. Injection molded self-cleaning surfaces

    DEFF Research Database (Denmark)

    Søgaard, Emil

    that are superhydrophobic based on topography rather than chemical compounds. Therefore, a novel method for fabricating superhydrophobic polymer surfaces with excellent water-repellant properties is developed. The method is based on microstructure fabrication and superposed nanostructures on silicon wafers. The nano......- and microstructured silicon is electroplated with nickel and the resulting nickel shim with inverse polarity is used in an injection molding process. A versatile injection molding process capable of producing different nano- and microstructures on areas larger than 10 cm2 is developed. Variotherm mold heating is used...... hierarchical structures with nanograss and holes. Water wetting tests are carried out using a pressure cell to control the water pressure. Microscopic wetting behavior of the structures is studied by optical transmission microscopy. Interestingly, it is found that the surface chemistry of the polymer changes...

  11. Single gate optimization for plastic injection mold

    Institute of Scientific and Technical Information of China (English)

    LI Ji-quan; LI De-qun; GUO Zhi-ying; LV Hai-yuan

    2007-01-01

    This paper deals with a methodology for single gate location optimization for plastic injection mold. The objective of the gate optimization is to minimize the warpage of injection molded parts, because warpage is a crucial quality issue for most injection molded parts while it is influenced greatly by the gate location. Feature warpage is defined as the ratio of maximum displacement on the feature surface to the projected length of the feature surface to describe part warpage. The optimization is combined with the numerical simulation technology to find the optimal gate location, in which the simulated annealing algorithm is used to search for the optimum. Finally, an example is discussed in the paper and it can be concluded that the proposed method is effective.

  12. High rate fabrication of compression molded components

    Energy Technology Data Exchange (ETDEWEB)

    Matsen, Marc R.; Negley, Mark A.; Dykstra, William C.; Smith, Glen L.; Miller, Robert J.

    2016-04-19

    A method for fabricating a thermoplastic composite component comprises inductively heating a thermoplastic pre-form with a first induction coil by inducing current to flow in susceptor wires disposed throughout the pre-form, inductively heating smart susceptors in a molding tool to a leveling temperature with a second induction coil by applying a high-strength magnetic field having a magnetic flux that passes through surfaces of the smart susceptors, shaping the magnetic flux that passes through surfaces of the smart susceptors to flow substantially parallel to a molding surface of the smart susceptors, placing the heated pre-form between the heated smart susceptors; and applying molding pressure to the pre-form to form the composite component.

  13. Neonatal Ear Molding: Timing and Technique.

    Science.gov (United States)

    Anstadt, Erin Elizabeth; Johns, Dana Nicole; Kwok, Alvin Chi-Ming; Siddiqi, Faizi; Gociman, Barbu

    2016-03-01

    The incidence of auricular deformities is believed to be ∼11.5 per 10,000 births, excluding children with microtia. Although not life-threatening, auricular deformities can cause undue distress for patients and their families. Although surgical procedures have traditionally been used to reconstruct congenital auricular deformities, ear molding has been gaining acceptance as an efficacious, noninvasive alternative for the treatment of newborns with ear deformations. We present the successful correction of bilateral Stahl's ear deformity in a newborn through a straightforward, nonsurgical method implemented on the first day of life. The aim of this report is to make pediatric practitioners aware of an effective and simple molding technique appropriate for correction of congenital auricular anomalies. In addition, it stresses the importance of very early initiation of ear cartilage molding for achieving the desired outcome.

  14. Ultrasonically-assisted Polymer Molding: An Evaluation

    Science.gov (United States)

    Moles, Matthew; Roy, Anish; Silberschmidt, Vadim

    Energy reduction in extrusion and injection molding processes can be achieved by the introduction of ultrasonic energy. Polymer flow can be enhanced on application of ultrasonic vibration, which can reduce the thermal and pressure input requirements to produce the same molding; higher productivity may also be achieved. In this paper, a design of an ultrasound-assisted injection mold machine is explored. An extrusion-die design was augmented with a commercial 1.5 kW ultrasonic transducer and sonotrode designed to resonate close to 20 kHz with up to 100 μm vibration amplitude. The design was evaluated with modal and thermal analysis using finite-element analysis software. The use of numerical techniques, including computational fluid dynamics, fluid-structure interaction and coupled Lagrangian-Eulerian method, to predict the effect of ultrasound on polymer flow was considered. A sonotrode design utilizing ceramic to enhance thermal isolation was also explored.

  15. The Elastic Mold Deformation During the Filling and Packing Stage of the Injection Molding Process

    Directory of Open Access Journals (Sweden)

    Stefan Kleindel

    2014-03-01

    Full Text Available The accurate numerical prediction of the mold filling process of long and thin walled parts is dependent on numerous factors. This paper investigates the effect of various influencing variables on the filling pattern by means of simulation and experimental validation. It was found that mold temperature, process settings and venting conditions have little effect on the predicted filling pattern. However, in the actual case study, the filling behavior observed during the experiments was significantly different compared to the numerical prediction. A structural finite element analysis of the moving mold half showed an unacceptable large deformation of the mold plates under injection pressure. A very good correlation between simulation and experiment was attained after improving the stiffness of the mold. Therefore it can be concluded, that the elasticity of the mold may have a significant influence on the filling pattern when long and thin walled products are considered. Furthermore, it was shown, that even an apparently stiff mold can exhibit a distinct deformation during filling and packing stage.

  16. Mold Simulator Study of Heat Transfer Phenomenon During the Initial Solidification in Continuous Casting Mold

    Science.gov (United States)

    Zhang, Haihui; Wang, Wanlin

    2017-01-01

    In this paper, mold simulator trials were firstly carried out to study the phenomena of the initial shell solidification of molten steel and the heat transfer across the initial shell to the infiltrated mold/shell slag film and mold. Second, a one-dimensional inverse heat transfer problem for solidification (1DITPS) was built to determine the temperature distribution and the heat transfer behavior through the solidifying shell from the measured shell thickness. Third, the mold wall temperature field was recovered by a 2DIHCP mathematical model from the measured in-mold wall temperatures. Finally, coupled with the measured slag film thickness and the calculations of 1DITPS and 2DIHCP, the thermal resistance and the thickness of liquid slag film in the vicinity of the meniscus were evaluated. The experiment results show that: the total mold/shell thermal resistance, the mold/slag interfacial thermal resistance, the liquid film thermal resistance, and the solid film thermal resistance is 8.0 to 14.9 × 10-4, 2.7 to 4.8 × 10-4, 1.5 to 4.6 × 10-4, and 3.9 to 6.8 × 10-4 m2 K/W, respectively. The percentage of mold/slag interfacial thermal resistance, liquid film thermal resistance, and solid film thermal resistance over the total mold/shell thermal resistance is 27.5 to 34.4, 17.2 to 34.0, and 38.5 to 48.8 pct, respectively. The ratio of radiation heat flux is around 14.1 to 51.9 pct in the liquid slag film.

  17. Natural latex (Hevea brasiliensis) mold for neovaginoplasty

    OpenAIRE

    2008-01-01

    OBJETIVO: avaliar a utilização do molde de látex natural (Hevea brasiliensis) como modificação à neovaginoplastia de McIndoe e Bannister em pacientes portadoras da síndrome de Mayer-Rokitansky-Küster-Hauser (MRKH). MÉTODOS: análise retrospectiva de nove pacientes com o diagnóstico de síndrome de MRKH, submetidas à neovaginoplastia pela técnica de McIndoe e Bannister com molde de látex natural. Foram avaliadas epitelização, amplitude e profundidade das neovaginas, ocorrência de coitos bem como...

  18. Powder injection molding of pure titanium

    Institute of Scientific and Technical Information of China (English)

    GUO Shibo; DUAN Bohua; HE Xinbo; QU Xuanhui

    2009-01-01

    An improved wax-based binder was developed for powder injection molding of pure titanium. A critical powder loading of 69 vol.% and a pseudo-plastic flow behavior were obtained by the feedstock based on the binder. The injection molding, debinding, and sintering process were studied. An ideal control of carbon and oxygen contents was achieved by thermal debinding in vacuum atmosphere (10-3 Pa). The mechanical properties of as-sintered specimens were less than those of titanium made by the conventional press-sintering process. Good shape retention and ±0.04 mm dimension deviation were achieved.

  19. Relationship Between Casting Distortion, Mold Filling, and Interfacial Heat Transfer in Sand Molds

    Energy Technology Data Exchange (ETDEWEB)

    J. K. Parker; K. A. Woodbury; T. S. Piwonka; Y. Owusu

    1999-09-30

    This project sought to determine the relationship between casting dimensions and interfacial heat transfer in aluminum alloy sand castings. The program had four parts; measurement of interfacial heat transfer coefficients in resin bonded and green sand molds, the measurement of gap formation in these molds, the analysis of castings made in varying gatings, orientations and thicknesses, and the measurement of residual stresses in castings in the as-cast and gate removed condition. New values for interfacial heat transfer coefficients were measured, a novel method for gap formation was developed, and the variation of casting dimensions with casting method, gating, and casting orientation in the mold was documented.

  20. Reduction of Injection Pressure for Thin Walled Molding using the Laser Metal Sintered Mold

    OpenAIRE

    米山, 猛; 内藤, 圭亮; 阿部, 諭; 宮丸, 充

    2010-01-01

    Using milling combined laser metal sintering, porous surface has been fabricated on the thin walled cavity closed by the surrounded thick cavity in the injection mold. Resin flows into the cavity of 2mm thick at first around the thin part and then flows into the thin cavity of 0.2mm thick with 11mm square by packing pressure. The packing pressure for filling the thin part was compared among laser metal sintered mold with or without porous surface, steel mold with or without porous block. The ...

  1. Tool steel quality and surface finishing of plastic molds

    Directory of Open Access Journals (Sweden)

    Rafael Agnelli Mesquita

    2010-01-01

    Full Text Available Plastic industry is today in a constant growth, demanding several products from other segments, which includes the plastic molds, mainly used in the injection molding process. Considering all the requirements of plastic molds, the surface finishing is of special interest, as the injected plastic part is able to reproduce any details (and also defects from the mold surface. Therefore, several aspects on mold finishing are important, mainly related to manufacturing conditions - machining, grinding, polishing and texturing, and also related to the tool steel quality, in relation to microstructure homogeneity and non-metallic inclusions (cleanliness. The present paper is then focused on this interrelationship between steel quality and manufacturing process, which are both related to the final quality of plastic mold surfaces. Examples are discussed in terms of surface finishing of plastic molds and the properties or the microstructure of mold steels.

  2. Affordable, Precision Reflector Mold Technology (PDRT08-029) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Advances in replication mold technology that reduce material costs, grinding time, and polishing time would enable fabrication of large, precision molds and possibly...

  3. Exploring the problem of mold growth and the efficacy of various mold inhibitor methods during moisture sorption isotherm measurements.

    Science.gov (United States)

    Yu, X; Martin, S E; Schmidt, S J

    2008-03-01

    Mold growth is a common problem during the equilibration of food materials at high relative humidity values using the standard saturated salt slurry method. Exposing samples to toluene vapor and mixing samples with mold inhibitor chemicals are suggested methods for preventing mold growth while obtaining isotherms. However, no published research was found that examined the effect of mold growth on isotherm performance or the efficacy of various mold inhibitor methods, including their possible effect on the physicochemical properties of food materials. Therefore, the objectives of this study were to (1) explore the effect of mold growth on isotherm performance in a range of food materials, (2) investigate the effectiveness of 4 mold inhibitor methods, irradiation, 2 chemical inhibitors (potassium sorbate and sodium acetate), and toluene vapor, on mold growth on dent corn starch inoculated with A. niger, and (3) examine the effect of mold inhibitor methods on the physicochemical properties of dent corn starch, including isotherm performance, pasting properties, gelatinization temperature, and enthalpy. Mold growth was found to affect starch isotherm performance by contributing to weight changes during sample equilibration. Among the 4 mold inhibitor methods tested, irradiation and toluene vapor were found to be the most effective for inhibiting growth of A. niger on dent cornstarch. However, both methods exhibited a significant impact on the starches' physiochemical properties, suggesting the need to probe the efficacy of other mold inhibitor methods and explore the use of new rapid isotherm instruments, which hamper mold growth by significantly decreasing measurement time.

  4. 240 Mold Sensitization in Chronic Rhinosinusitis Patients

    OpenAIRE

    2012-01-01

    Background It is estimated that about 10% of the population have IgE antibodies to common inhalant molds. Exposure to fungal allergens could be linked to the presence and persistence of asthma, rhinitis and atopic dermatitis. Mold sensitization is a risk factor for development and deterioration of upper airway allergy, especially chronic rhinosinusitis. We addressed the incidence of mold allergy measured as specific IgE to molds and skin prick tests in chronic sinusitis patients. We assessed ...

  5. COMPUTER AIDED THREE DIMENSIONAL DESIGN OF MOLD COMPONENTS

    Directory of Open Access Journals (Sweden)

    Kerim ÇETİNKAYA

    2000-02-01

    Full Text Available Sheet metal molding design with classical methods is formed in very long times calculates and drafts. At the molding design, selection and drafting of most of the components requires very long time because of similar repetative processes. In this study, a molding design program has been developed by using AutoLISP which has been adapted AutoCAD packet program. With this study, design of sheet metal molding, dimensioning, assemly drafting has been realized.

  6. Comparison of two setups for induction heating in injection molding

    DEFF Research Database (Denmark)

    Menotti, Stefano; Hansen, Hans Nørgaard; Bissacco, Giuliano

    2015-01-01

    To eliminate defects and improve the quality of molded parts, increasing the mold temperature is one of the applicable solutions. A high mold temperature can increase the path flow of the polymer inside the cavity allowing reduction of the number of injection points, reduction of part thickness, ...

  7. 21 CFR 874.3430 - Middle ear mold.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Middle ear mold. 874.3430 Section 874.3430 Food... DEVICES EAR, NOSE, AND THROAT DEVICES Prosthetic Devices § 874.3430 Middle ear mold. (a) Identification. A middle ear mold is a preformed device that is intended to be implanted to reconstruct the middle...

  8. Onychomycosis by molds. Report of 78 cases.

    Science.gov (United States)

    Bonifaz, Alexandro; Cruz-Aguilar, Pamela; Ponce, Rosa María

    2007-01-01

    A retrospective study of onychomycohosis by molds was carried out during a 14-year period (1992-2005). All cases were clinically and mycologically proven (repetitive KOH and culture) and then each of the molds was identified. A total of 5,221 cases of onychomycosis were evaluated, 78 of which were molds (1.49%). Mean patient age was 44.1 years. 75/78 cases occurred in toenails. Associated factors were detected in 39/78 (50.0%) cases, with the major ones being: peripheral vascular disease, contact with soil, and trauma. The most frequent clinical presentation was distal and lateral subungual onychomycosis (DLSO), in 54/78 cases (69%). The most frequent causative agents were: Scopulariopsis brevicaulis in 34/78 cases and Aspergillus niger in 13/78 cases. Onychomycoses by molds are infrequent; in this study they accounted for 1.49% of cases. The clinical features are virtually similar to those caused by dermatophytes, which makes the clinicomycological tests necessary.

  9. Mold Die Making. 439-322/324.

    Science.gov (United States)

    Yunke, P.; And Others

    Each unit in this curriculum guide on mold die making contains an introduction, objectives, materials required, lessons, space for notes, figures, and diagrams. There are 10 units in this guide: (1) introduction to Electrical Discharge Machining (EDM); (2) EDM principles; (3) the single pulse; (4) EDM safety; (5) electrode material; (6) electrode…

  10. Progress in Titanium Metal Powder Injection Molding

    Directory of Open Access Journals (Sweden)

    Randall M. German

    2013-08-01

    Full Text Available Metal powder injection molding is a shaping technology that has achieved solid scientific underpinnings. It is from this science base that recent progress has occurred in titanium powder injection molding. Much of the progress awaited development of the required particles with specific characteristics of particle size, particle shape, and purity. The production of titanium components by injection molding is stabilized by a good understanding of how each process variable impacts density and impurity level. As summarized here, recent research has isolated the four critical success factors in titanium metal powder injection molding (Ti-MIM that must be simultaneously satisfied—density, purity, alloying, and microstructure. The critical role of density and impurities, and the inability to remove impurities with sintering, compels attention to starting Ti-MIM with high quality alloy powders. This article addresses the four critical success factors to rationalize Ti-MIM processing conditions to the requirements for demanding applications in aerospace and medical fields. Based on extensive research, a baseline process is identified and reported here with attention to linking mechanical properties to the four critical success factors.

  11. Residual stresses in injection molded products

    NARCIS (Netherlands)

    Jansen, K.M.B.

    2015-01-01

    During the molding process residual stresses are formed due to thermal contraction during cooling as well as the local pressure history during solidification. In this paper a simple analytical model is reviewed which relates residual stresses, product shrinkage as well as warpage to the temperature

  12. Molding cork sheets to complex shapes

    Science.gov (United States)

    Sharpe, M. H.; Simpson, W. G.; Walker, H. M.

    1977-01-01

    Partially cured cork sheet is easily formed to complex shapes and then final-cured. Temperature and pressure levels required for process depend upon resin system used and final density and strength desired. Sheet can be bonded to surface during final cure, or can be first-formed in mold and bonded to surface in separate step.

  13. Flexible Interior-Impression-Molding Tray

    Science.gov (United States)

    Anders, Jeffrey E.

    1991-01-01

    Device used inside combustion chamber of complicated shape for nondestructive evaluation of qualities of welds, including such features as offset, warping, misalignment of parts, and dropthrough. Includes flexible polypropylene tray trimmed to fit desired interior surface contour. Two neodymium boron magnets and inflatable bladder attached to tray. Tray and putty inserted in cavity to make mold of interior surface.

  14. Fabrication of silicon molds for polymer optics

    DEFF Research Database (Denmark)

    Nilsson, Daniel; Jensen, Søren; Menon, Aric Kumaran

    2003-01-01

    A silicon mold used for structuring polymer microcavities for optical applications is fabricated, using a combination of DRIE (deep reactive ion etching) and anisotropic chemical wet etching with KOH + IPA. For polymer optical microcavities, low surface roughness and vertical sidewalls are often...

  15. A REVOLUTION IN MOLD IDENTIFICATION AND ENUMERATION

    Science.gov (United States)

    More than 100 assay were developed to identify and quantify indoor molds using quantitiative PCR (QPCR) assays. This technology incorporates fluorigenic 5' nuclease (TaqMan�) chemistry directed at the nuclear ribosomal RNA operon internal transcribed spacer regions (ITS1 or ITS2...

  16. Residual thermal stresses in injection molded products

    NARCIS (Netherlands)

    Zoetelief, W.F.; Douven, L.F.A.; Ingen Housz, A.J.

    1996-01-01

    Nonisothermal flow of a polymer melt in a cold mold cavity introduces stresses that are partly frozen-in during solidification. Flow-induced stresses cause anisotropy of mechanical, thermal, and optical properties, while the residual thermal stresses induce warpage and stress-cracking. In this study

  17. Injection molding of micro patterned PMMA plate

    Institute of Scientific and Technical Information of China (English)

    Yeong-Eun YOO; Tae-Hoon KIM; Tae-Jin JE; Doo-Sun CHOI; Chang-Wan KIM; Sun-Kyung KIM

    2011-01-01

    A plastic plate with surface micro features was injection molded to investigate the effect of pressure rise of melt on the replication of the micro structures. Prism pattern, which is used in many optical applications, was selected as a model pattern. The prism pattern is 50 μm in pitch and 108° in the vertical angle. The overall size of the plate was 335 mm×213 mm and the thickness of the plate varied linearly from 2.6 mm to 0.7 mm. The prism pattern was firstly machined on the nickel plated core block using micro diamond tool and this machined pattern core was installed in a mold for injection molding of prism patterned plate. Polymethyl methacrylate (PMMA) was used as a molding material. The pressure and temperature of the melt in the cavity were measured at different positions in the cavity and the replication of the pattern was also measured at the same positions. The results show that the pressure or temperature profile through the process depends on the shape and the size of the plate. The replication is affected by the temperature and pressure profiles at the early stage of filling, which is right after the melt reaches the position to be measured.

  18. 浮选柱浮选金矿矿泥半工业试验研究%Semi Industrial Test by Analysis of Flotation Column Flotation Gold Slime

    Institute of Scientific and Technical Information of China (English)

    管乐; 高云; 孙日舜

    2013-01-01

    本文介绍了某金矿应用浮选柱浮选矿泥所进行的半工业试验过程及结果分析。通过试验及数据分析,表明了浮选柱适合该金矿浮选矿泥,并能够取得比较好的技术指标。%This paper introduces the application of flotation column flotation gold slime and the analysis of semi industrial test process and result in a gold mine. Through the test and data analysis, it shows that the flotation column for the gold flotation slime, and can better achieve technical index.

  19. Characteristics and influence factors of mold filling process in permanent mold with a slot gating system

    Institute of Scientific and Technical Information of China (English)

    Chang Qingming; Chen Xia; Chen Changjun; Bao Siqian; David Schwam

    2009-01-01

    The main problems caused by improper gating are entrained aluminum oxide films and entrapped gas. In this study, the slot gating system is employed to improve mold filling behavior and therefore, to improve the quality of aluminum castings produced in permanent molds. An equipment as well as operation procedures for real-time X-ray radiography of molten aluminum flowing into permanent molds have been developed. Graphite molds transparent to X-rays are utilized which make it possible to observe the flow pattern through a number of vertically oriented gating systems. The investigation discovers that there are many influencing factors on the mold filling process. This paper focuses its research on some of the factors, such as the dimensions of the vertical riser and slot thickness, as well as roughness of the coating layer. The results indicate that molten metal can smoothly fill into casting cavity with a proper slot gating system. A bigger vertical riser, proper slot thickness and rougher coating can provide not only a better mold filling pattern, but also hot melt into the top of the cavity. A proper temperature gradient is obtainable, higher at the bottom and lower at the top of the casting cavity, which is in favor of feeding during casting solidification.

  20. 煤泥高效离心脱水机脱水效果的试验研究%Experimental study on dehydration effects of efficient slime centrifuge

    Institute of Scientific and Technical Information of China (English)

    杨建国; 刘传印; 程晓峰; 王兴兴

    2011-01-01

    Aiming at the dehydration process of fine coal with the slime centrifuge, influences of feedings size, feedings concentration, centrifugal factor and residence duration on the dehydration effect are studied. The re sults show that variation of the feedings characters have great influences on the dehydration performance of the slime centrifuge, so when they change, the centrifuge's working parameters need to adjust so as to ensure the dehydration performance. The centrifugal factor and the residence duration of the efficient slime centrifuge can be adjusted precisely as the feedings characters change, thus it has good adaptability for feedings with different characters, and is has more advantages than the traditional slime centrifuge.%针对煤泥离心脱水机对细粒煤的脱水过程,研究了入料粒度、入料浓度、离心因数与停留时间对脱水效果的影响.结果表明,入料性质的变化对煤泥离心脱水机脱水效果的影响较为显著,入料性质变化时应及时调整离心机参数才能确保脱水效果.煤泥高效离心机的离心因数、物料停留时间可根据物料性质的改变进行精确调节,对不同性质的入料均有较好的适应性,相比较传统煤泥离心机有较大的优势.

  1. Computer simulation for centrifugal mold filling of precision titanium castings

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    Computer simulation codes were developed based on a proposed mathematical model for centrifugal mold filling processes and previous computer software for 3D mold filling and solidification of castings (CASM-3D for Windows). Sample simulations were implemented for mold filling processes of precision titanium castings under gravity and different centrifugal casting techniques. The computation results show that the alloy melt has a much stronger mold filling ability for thin section castings under a centrifugal force field than that only under the gravity. A "return back" mold filling manner is showed to be a reasonable technique for centrifugal casting processes, especially for thin section precision castings.

  2. Testing single point incremental forming molds for thermoforming operations

    Science.gov (United States)

    Afonso, Daniel; de Sousa, Ricardo Alves; Torcato, Ricardo

    2016-10-01

    Low pressure polymer processing processes as thermoforming or rotational molding use much simpler molds then high pressure processes like injection. However, despite the low forces involved with the process, molds manufacturing for this operations is still a very material, energy and time consuming operation. The goal of the research is to develop and validate a method for manufacturing plastically formed sheets metal molds by single point incremental forming (SPIF) operation for thermoforming operation. Stewart platform based SPIF machines allow the forming of thick metal sheets, granting the required structural stiffness for the mold surface, and keeping the short lead time manufacture and low thermal inertia.

  3. The Facility and Process Technics of Polyethylene Rotational Molding

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@ 1. Introduction Rotational molding is the process by which hollow plastic parts are formed. It mainly processes the product which Injection molding and Blow molding can not process medium-sized, large-sized and super large-sized plastic parts. The technics may turn out a tub, dustbin, stock tank, sailboat. The research institute of Lanzhou introduces a suit of RS-16 Rotational Molding Machine from Germany Reinhadt Co. on 1990. It mainly put up experiment and smallscale production. RS-16 rotational molding machine is a single arm and di-axial equipment. It is consisting of a gas heated sintering oven, cooling chamber, mouldcarrying carriage and a controlling unit.

  4. Wavelet Packet Decomposition to Characterize Injection Molding Tool Damage

    Directory of Open Access Journals (Sweden)

    Tomaž Kek

    2016-02-01

    Full Text Available This paper presents measurements of acoustic emission (AE signals during the injection molding of polypropylene with new and damaged mold. The damaged injection mold has cracks induced by laser surface heat treatment. Standard test specimens were injection molded, commonly used for examining the shrinkage behavior of various thermoplastic materials. The measured AE burst signals during injection molding cycle are presented. For injection molding tool integrity prediction, different AE burst signals’ descriptors are defined. To lower computational complexity and increase performance, the feature selection method was implemented to define a feature subset in an appropriate multidimensional space to characterize the integrity of the injection molding tool and the injection molding process steps. The feature subset was used for neural network pattern recognition of AE signals during the full time of the injection molding cycle. The results confirm that acoustic emission measurement during injection molding of polymer materials is a promising technique for characterizing the integrity of molds with respect to damage, even with resonant sensors.

  5. Ultra-precision molding of chalcogenide glass aspherical lens

    Science.gov (United States)

    Zhang, Feng; Wang, Zhibin; Zhang, Yunlong; Su, Ying; Guo, Rui; Xu, Zengqi; Liu, Xuanmin

    2016-10-01

    With the development of infrared optical systems in military and civil areas, chalcogenide glass aspherical lens possess some advantages, such as large infrared transmission, good thermal stability performance and image quality. Aspherical lens using chalcogenide glass can satisfy the requirements of modern infrared optical systems. Therefore, precision manufacturing of chalcogenide glass aspheric has received more and more attention. The molding technology of chalcogenide glass aspheric has become a research hotspot, because it can achieve mass and low cost manufacturing. The article of molding technology is focusing on a kind of chalcogenide glass aspherical lens. We report on design and fabrication of the mold that through simulation analysis of molding. Finally, through molding test, the fabrication of mold's surface and parameters of molding has been optimized, ensuring the indicators of chalcogenide glass aspherical lens meet the requirements.

  6. Direct molding of pavement tiles made of ground tire rubber

    Science.gov (United States)

    Quadrini, Fabrizio; Gagliardi, Donatella; Tedde, Giovanni Matteo; Santo, Loredana; Musacchi, Ettore

    2016-10-01

    Large rubber products can be molded by using only ground tire rubber (GTR) without any additive or binder due to a new technology called "direct molding". Rubber granules and powders from tire recycling are compression molded at elevated temperatures and pressures. The feasibility of this process was clearly shown in laboratory but the step to the industrial scale was missing. Thanks to an European Project (SMART "Sustainable Molding of Articles from Recycled Tires") this step has been made and some results are reported in this study. The press used for compression molding is described. Some tests were made to measure the energy consumption so as to evaluate costs for production in comparison with conventional technologies for GTR molding (by using binders). Results show that 1 m2 tiles can be easily molded with several thicknesses in a reasonable low time. Energy consumption is higher than conventional technologies but it is lower than the cost for binders.

  7. Detecção da produção de slime por estafilococos coagulase-negativa isolados de cateter venoso central

    Directory of Open Access Journals (Sweden)

    E. L. Pizzolitto

    2009-01-01

    Full Text Available

    A produção de slime é um importante fator de virulência dos estafilococos coagulase-negativa, permitindo-lhes aderir sobre as superfícies lisas de biomateriais, e por isso, é associada aos processos de infecção de implantes. No presente estudo a produção de slime em 27 cepas de estafilococos coagulase-negativa foi investigada por cultura em ágar vermelho Congo (77,7% de positividade, método espectrofotométrico ou da microplaca (81,4% de positividade e microscopia eletrônica de varredura (88,9% de positividade. Foi também avaliada a resistência de estafilococos coagulasenegativa a vários antimicrobianos usando a técnica do disco difusão. A porcentagem de resistência à penicilina G, oxacilina, eritromicina, clindamicina e gentamicina em estafilococos produtores de slime foi respectivamente de 88,9%; 70,4%; 81,5%; 66,7% e 59,2%; todos os estafilococos coagulase-negativa foram vancomicina sensíveis. As cepas isoladas de cateter venoso central foram identificadas por método convencional e sistema API Staph. Os 27 estafilococos coagulase-negativa foram identificados como: S. saprophyticus (3,7%, S. xylosus (7,4%, S. haemolyticus (14,8%, S. epidermidis (37,0%, S. warneri (14,8%, S. lugdunensis (7,4%, S. hominis (7,4%, S. schleiferi (3,7% e S. chromogenes (3,7%. Pode-se concluir que entre a maioria das espécies Staphylococcus coagulase-negativa houve associação entre a produção de slime, origem nosocomial das cepas e reduzida sensibilidade aos antimicrobianos, sugerindo potencial patogênico no ambiente hospitalar. Palavras-chave: estafilococos coagulase-negativa; slime; fatores de virulência; polissacarídeo extracelular; biofilme; sensibilidade aos antimicrobianos.

  8. An education belief worth reflection: Molding intellectuals

    Institute of Scientific and Technical Information of China (English)

    Lu Jie

    2006-01-01

    Molding intellectuals is one of the expectations people have,which comes from a deep-rooted belief in education.The humanity hypothesis of this belief is to take knowledge and the pursuit of knowledge as the only prescription for human beings.This hypothesis overturns the relation of knowledge and life.Intellectuals make scientific paradigm as the limit of knowledge.Experience and consciousness outside the paradigm are ejected from the scope of knowledge.Accordingly,knowledge of intellectuals is broken away from a human being's life.Under the domination of this conception of knowledge,the world of intellectuals has become a world deficient of meaning.The belief that education molds intellectuals should be deconstructed gradually,with criticism in both practice and theory.

  9. Application of Derrick Corporation's stack sizer technology for slimes reduction in 6 inch clean coal hydrocyclone circuits

    Energy Technology Data Exchange (ETDEWEB)

    Brodzik, P.

    2009-04-15

    The article discusses the successful introduction of Derrick Corporation's Stack Sizer technology for removing minus 200 mesh slimes from 6-inch coal hydrocyclone underflow prior to froth flotation or dewatering by screen bowl centrifuges. In 2006, the James River Coal Company selected the Stack Sizer fitted with Derrick 150 micron and 100 micron urethane screen panels for removal of the minus 100 mesh high ash clay fraction from the clean coal spiral product circuits. After this application proved successful, Derrick Corporation introduced new 75 micron urethane screen panels for use on the Stack Sizer. Evaluation of feed slurry to flotation cells and screen bowl centrifuges showed significant amounts of minus 75 micron that could potentially be removed by efficient screening technology. Removal of the minus 75 micron fraction was sought to reduce ash and moisture content of the final clean coal product. Full-scale lab tests confirmed that the Stack Sizer fitted with Derrick 75 micron urethane screen panels consistently reduced the minus 75 micron percentage in coal slurry from 6-inch clean coal hydrocyclone underflow that is approximately 15 to 20% solid by-weight and 30 to 60% minus 75 micron to a clean coal fraction that is approximately 13 to 16% minus 75 micron. As a result total ash is reduced from approximately 36 to 38% in the hydrocyclone underflow to 14 to 16% in the oversize product fraction form the Stack Sizers. 1 fig., 2 tabs., 5 photos.

  10. Fabrication of cost effective iron ore slime ceramic membrane for the recovery of organic solvent used in coke production

    Institute of Scientific and Technical Information of China (English)

    V.Singh; N.K.Meena; A.K.Golder; C.Das

    2016-01-01

    Improvement of coking properties of sub-bituminous coal (A) and bituminous coal (B) was done using blended organic solvents,namely,n-methyl-2-pyrrolidinone (NMP) and ethylenediamine (EDA).Various solvent blends were employed for the coal extraction under the total reflux condition.A low-cost ceramic membrane was fabricated using industrial waste iron ore slime of M/s TATA steel R&D,Jamshedpur (India) to separate out the dissolved coking fraction from the solvent-coal mixture.Membrane separations were carried out in a batch cell,and around 75 % recovered NMP was reused.The fractionated coal properties were determined using proximate and ultimate analyses.In the case of bituminous coal,the ash and sulfur contents were decreased by 99.3 % and 79.2 %,respectively,whereas,the carbon content was increased by 23.9 % in the separated coal fraction.Three different cleaning agents,namely deionized water,sodium dodecyl sulphate and NMP were used to regain the original membrane permeability for the reusing.

  11. Manufacturing Science of Improved Molded Optics

    Science.gov (United States)

    2013-12-05

    a physical point shear thinning is an unlikely explanation. In a study of friction mechanisms in polymer extrusion , Joshi et al.27 present a...41 Appendix C2 – glass extrusion paper draft 61 Appendix C3 - ring compression test paper draft (Navier law) 97 D. Protective coatings...complex thermo-mechanical behavior of an optical glass during simulation of the lens molding, extrusion and other glass forming processes. This

  12. Diagnosis parameters of mold filling pattern for optimization of a casting system

    OpenAIRE

    2012-01-01

    For optimal design of a gating system, the setting of diagnosis parameters is very important. In this study, the permanent mold casting process was selected because most of the other casting processes have more complicated factors that influence the mold filling pattern compared to the permanent mold casting process, such as the surface roughness of mold, gas generation from the mold wash and binder of sand mold, and the gas permeability through a sand mold, etc. Two diagnosis parameters (fl...

  13. Gastroresistant capsular device prepared by injection molding.

    Science.gov (United States)

    Zema, Lucia; Loreti, Giulia; Melocchi, Alice; Maroni, Alessandra; Palugan, Luca; Gazzaniga, Andrea

    2013-01-20

    In the present work, the possibility of manufacturing by injection molding (IM) a gastro-resistant capsular device based on hydroxypropyl methyl cellulose acetate succinate (HPMCAS) was investigated. By performing as an enteric soluble container, such a device may provide a basis for the development of advantageous alternatives to coated dosage forms. Preliminarily, the processability of the selected thermoplastic polymer was evaluated, and the need for a plasticizer (polyethylene glycol 1500) in order to counterbalance the glassy nature of the molded items was assessed. However, some critical issues related to the physical/mechanical stability (shrinkage and warpage) and opening time of the device after the pH change were highlighted. Accordingly, an in-depth formulation study was carried out taking into account differing release modifiers potentially useful for enhancing the dissolution/disintegration rate of the capsular device at intestinal pH values. Capsule prototypes with thickness of 600 and 900 μm containing Kollicoat(®) IR and/or Explotab(®) CLV could be manufactured, and a promising performance was achieved with appropriate gastric resistance in pH 1.2 medium and break-up in pH 6.8 within 1h. These results would support the design of a dedicated mold for the development of a scalable manufacturing process.

  14. Fractal phenomena in powder injection molding process

    Institute of Scientific and Technical Information of China (English)

    郑洲顺; 曲选辉; 李云平; 雷长明; 段柏华

    2003-01-01

    The complicated characteristics of the powder were studied by fractal theory. It is illustrated that powder shape, binder structure, feedstock and mold-filling flow in powder injection molding process possess obvious fractal characteristics. Based on the result of SEM, the fractal dimensions of the projected boundary of carbonylic iron and carbonylic nickel particles were determined to be 1.074±0.006 and 1.230±0.005 respectively by box counting measurement. The results show that the fractal dimension of the projected boundary of carbonylic iron particles is close to smooth curve of one-dimension, while the fractal dimension of the projected boundary of carbonylic nickel particle is close to that of trisection Koch curve, indicating that the shape characteristics of carbonylic nickel particles can be described and analyzed by the characteristics of trisection Koch curve. It is also proposed that the fractal theory can be applied in the research of powder injection molding in four aspects.

  15. Water modeling of mold powder entrapment in slab continuous casting mold

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The optimal parameters were determined by the water modeling of slab casting. It was found that there are mainly three types of mold powder entrapment in slab continuous casting, i.e., the entrapment caused by the shearing flow near the narrow face of mold, the entrapment caused by vortexes around the submerged entry nozzle (SEN), and the entrapment caused by the Ar bubbling.Both the velocity of the surface flow and the level fluctuation of the liquids are enlarged with increasing the casting speed, reducing the submersion depth of SEN, decreasing the downward angles of the nozzle outlets, and increasing the Ar flowrate, all of which increase the tendency of mold powder entrapment. Among the four above-mentioned factors, casting speed has the largest effect.

  16. Effect of mold treatment by solvent on PDMS molding into nanoholes

    Science.gov (United States)

    Con, Celal; Cui, Bo

    2013-09-01

    Polydimethylsiloxane (PDMS) is the most popular and versatile material for soft lithography due to its flexibility and easy fabrication by molding process. However, for nanoscale patterns, it is challenging to fill uncured PDMS into the holes or trenches on the master mold that is coated with a silane anti-adhesion layer needed for clean demolding. PDMS filling was previously found to be facilitated by diluting it with toluene or hexane, which was attributed to the great reduction of viscosity for diluted PDMS. Here, we suggest that the reason behind the improved filling for diluted PDMS is that the diluent solvent increases in situ the surface energy of the silane-treated mold and thus the wetting of PDMS to the mold surface. We treated the master mold surface (that was already coated with a silane anti-adhesion monolayer) with toluene or hexane, and found that the filling by undiluted PMDS into the nanoscale holes on the master mold was improved despite the high viscosity of the undiluted PDMS. A simple estimation based on capillary filing into a channel also gives a filling time on the millisecond scale, which implies that the viscosity of PMDS should not be the limiting factor. We achieved a hole filling down to sub-200-nm diameter that is smaller than those of the previous studies using regular Sylgard PDMS (not hard PDMS, Dow Corning Corporation, Midland, MI, USA). However, we are not able to explain using a simple argument based on wetting property why smaller, e.g., sub-100-nm holes, cannot be filled, for which we suggested a few possible factors for its explanation.

  17. Mold deformation in soft UV-nanoimprint lithography

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    UV-nanoimprint lithography (UV-NIL) using a soft mold is a promising technique with low cost and high throughput for producing the submicron scale large-area patterns. However, the deformations of the soft mold during imprinting process which can cause serious consequences have to be understood for the practical application of the process. This paper investigated the deformation of the soft mold by theoretical analyses, numerical simulations, and experimental studies. We simulated the mold deformation using a simplified model and finite element method. The simulation and the related experimental results agree well with each other. Through the investigation, the mechanism and affected factors of the mold deformation are revealed, and some useful conclusions have been achieved. These results will be valuable in optimizing the imprinting process conditions and mold design for improving the quality of transferred patterns.

  18. Three-Dimensional Modeling of Glass Lens Molding

    DEFF Research Database (Denmark)

    Sarhadi, Ali; Hattel, Jesper Henri; Hansen, Hans Nørgaard

    2015-01-01

    The required accuracy for the final dimensions of the molded lenses in wafer-based precision glass molding as well as the need for elimination of costly experimental trial and error calls for numerical simulations. This study deals with 3D thermo-mechanical modeling of the wafer-based precision...... glass lens molding process. First, a comprehensive 3D thermo-mechanical model of glass is implemented into a FORTRAN user subroutine (UMAT) in the FE program ABAQUS, and the developed FE model is validated with both a well-known sandwich seal test and experimental results of precision molding of several...... glass rings. Afterward, 3D thermo-mechanical modeling of the wafer-based glass lens manufacturing is performed to suggest a proper molding program (i.e., the proper set of process parameters including preset force-time and temperature-time histories) for molding a wafer to a desired dimension...

  19. Snow molds: A group of fungi that prevail under snow.

    Science.gov (United States)

    Matsumoto, Naoyuki

    2009-01-01

    Snow molds are a group of fungi that attack dormant plants under snow. In this paper, their survival strategies are illustrated with regard to adaptation to the unique environment under snow. Snow molds consist of diverse taxonomic groups and are divided into obligate and facultative fungi. Obligate snow molds exclusively prevail during winter with or without snow, whereas facultative snow molds can thrive even in the growing season of plants. Snow molds grow at low temperatures in habitats where antagonists are practically absent, and host plants deteriorate due to inhibited photosynthesis under snow. These features characterize snow molds as opportunistic parasites. The environment under snow represents a habitat where resources available are limited. There are two contrasting strategies for resource utilization, i.e., individualisms and collectivism. Freeze tolerance is also critical for them to survive freezing temperatures, and several mechanisms are illustrated. Finally, strategies to cope with annual fluctuations in snow cover are discussed in terms of predictability of the habitat.

  20. Replication of optical microlens arrays using photoresist coated molds

    DEFF Research Database (Denmark)

    Chakrabarti, Maumita; Dam-Hansen, Carsten; Stubager, Jørgen

    2016-01-01

    A cost reduced method of producing injection molding tools is reported and demonstrated for the fabrication of optical microlens arrays. A standard computer-numerical-control (CNC) milling machine was used to make a rough mold in steel. Surface treatment of the steel mold by spray coating...... the light engine. Polymer injection molded microlens arrays were produced from both the rough and coated molds and have been characterized for lenslet parameters, surface quality, light scattering, and acceptance angle. The surface roughness (Ra) is improved approximately by a factor of two after...... the coating process and the light scattering is reduced so that the molded microlens array can be used for the color mixing application. The measured accepted angle of the microlens array is 40° which is in agreement with simulations....

  1. Validation of three-dimensional micro injection molding simulation accuracy

    DEFF Research Database (Denmark)

    Tosello, Guido; Costa, F.S.; Hansen, Hans Nørgaard

    2011-01-01

    length, injection pressure profile, molding mass and flow pattern. The importance of calibrated micro molding process monitoring for an accurate implementation strategy of the simulation and its validation has been demonstrated. In fact, inconsistencies and uncertainties in the experimental data must...... be minimized to avoid introducing uncertainties in the simulation calculations. Simulations of bulky sub-100 milligrams micro molded parts have been validated and a methodology for accurate micro molding simulations was established.......Data analysis and simulations on micro-molding experiments have been conducted. Micro molding simulations have been executed taking into account actual processing conditions implementation in the software. Various aspects of the simulation set-up have been considered in order to improve...

  2. Shape retention of injection molded stainless steel compacts

    Institute of Scientific and Technical Information of China (English)

    LI Yi-min; K.A.Khalil; HUANG Bai-yun

    2005-01-01

    The effects of the binder composition, the powder loading, the thermal properties of feedstocks, and the injection molding parameters on the compact shape retention for metal injection molding 17-4PH stainless steel were investigated. The high-density polyethylene is more effective than ethylene vinyl acetate as a second component of the wax-based binder to retain compact shape due to its higher pyrolytic temperature and less heat of fusion. The compact distortion decreases with increasing the powder loading, molding pressure and molding temperature. There exists an optimal process combination including the powder loading of 68%, molding pressure of 120 MPa and molding temperature of 150 ℃. Under this process condition, the percentage of distorted compacts is the lowest.

  3. Effect of superheat, mold, and casting materials on the metal/mold interfacial heat transfer during solidification in graphite-lined permanent molds

    Science.gov (United States)

    Prabhu, K. Narayan; Suresha, K. M.

    2004-10-01

    Heat transfer during the solidification of an Al-Cu-Si alloy (LM4) and commercial pure tin in single steel, graphite, and graphite-lined metallic (composite) molds was investigated. Experiments were carried out at three different superheats. In the case of composite molds, the effect of the thickness of the graphite lining and the outer wall on heat transfer was studied. Temperatures at known locations inside the mold and casting were used to solve the Fourier heat conduction equation inversely to yield the casting/mold interfacial heat flux transients. Increased melt superheats and higher thermal conductivity of the mold material led to an increase in the peak heat flux at the metal/mold interface. Factorial experiments indicated that the mold material had a significant effect on the peak heat flux at the 5% level of significance. The ratio of graphite lining to outer steel wall and superheat had a significant effect on the peak heat flux in significance range varying between 5 and 25%. A heat flux model was proposed to estimate the maximum heat flux transients at different superheat levels of 25 to 75 °C for any metal/mold combinations having a thermal diffusivity ratio (α R) varying between 0.25 and 6.96. The heat flow models could be used to estimate interfacial heat flux transients from the thermophysical properties of the mold and cast materials and the melt superheat. Metallographic analysis indicated finer microstructures for castings poured at increased melt superheats and cast in high-thermal diffusivity molds.

  4. Virtual Mold Technique in Thermal Stress Analysis during Casting Process

    Institute of Scientific and Technical Information of China (English)

    Si-Young Kwak; Jae-Wook Baek; Jeong-Ho Nam; Jeong-Kil Choi

    2008-01-01

    It is important to analyse the casting product and the mold at the same time considering thermal contraction of the casting and thermal expansion of the mold. The analysis considering contact of the casting and the mold induces the precise prediction of stress distribution and the defect such as hot tearing. But it is difficult to generate FEM mesh for the interface of the casting and the mold. Moreover the mesh for the mold domain spends lots of computational time and memory for the analysis due to a number of meshes. Consequently we proposed the virtual mold technique which only uses mesh of the casting part for thermal stress analysis in casting process. The spring bar element in virtual mold technique is used to consider the contact of the casting and the mold. In general, a volume of the mold is much bigger than that of casting part, so the proposed technique decreases the number of mesh and saves the computational memory and time greatly. In this study, the proposed technique was verified by the comparison with the traditional contact technique on a specimen. And the proposed technique gave satisfactory results.

  5. Deformation analysis considering thermal expansion of injection mold

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jun Hyung; Yi, Dae Eun; Jang, Jeong Hui; Lee, Min Seok [Samsung Electronics Co., LTD., Seoul (Korea, Republic of)

    2015-09-15

    In the design of injection molds, the temperature distribution and deformation of the mold is one of the most important parameters that affect the flow characteristics, flash generation, and surface appearance, etc. Plastic injection analyses have been carried out to predict the temperature distribution of the mold and the pressure distribution on the cavity surface. As the input loads, we transfer the temperature and pressure results to the structural analysis. We compare the structural analysis results with the thermal expansion effect using the actual flash and step size of a smartphone cover part. To reduce the flash problem, we proposed a new mold design, and verified the results by performing simulations.

  6. Effect of mold rotation on the bifilar electroslag remelting process

    Science.gov (United States)

    Shi, Xiao-fang; Chang, Li-zhong; Wang, Jian-jun

    2015-10-01

    A novel electroslag furnace with a rotating mold was fabricated, and the effects of mold rotational speed on the electroslag remelting process were investigated. The results showed that the chemical element distribution in ingots became uniform and that their compact density increased when the mold rotational speed was increased from 0 to 28 r/min. These results were attributed to a reasonable mold speed, which resulted in a uniform temperature in the slag pool and scattered the metal droplets randomly in the metal pool. However, an excessive rotational speed caused deterioration of the solidification structure. When the mold rotational speeds was increased from 0 to 28 r/min, the size of Al2O3 inclusions in the electroslag ingot decreased from 4.4 to 1.9 μm. But the excessive mold rotational speed would decrease the ability of the electroslag remelting to remove the inclusions. The remelting speed gradually increased, which resulted in reduced power consumption with increasing mold rotational speed. This effect was attributed to accelerated heat exchange between the consumable electrode and the molten slag, which resulted from mold rotation. Nevertheless, when the rotational speed reached 28 r/min, the remelting speed did not change because of limitations of metal heat conduction. Mold rotation also improved the surface quality of the ingots by promoting a uniform temperature distribution in the slag pool.

  7. A hybrid optimization approach in non-isothermal glass molding

    Science.gov (United States)

    Vu, Anh-Tuan; Kreilkamp, Holger; Krishnamoorthi, Bharathwaj Janaki; Dambon, Olaf; Klocke, Fritz

    2016-10-01

    Intensively growing demands on complex yet low-cost precision glass optics from the today's photonic market motivate the development of an efficient and economically viable manufacturing technology for complex shaped optics. Against the state-of-the-art replication-based methods, Non-isothermal Glass Molding turns out to be a promising innovative technology for cost-efficient manufacturing because of increased mold lifetime, less energy consumption and high throughput from a fast process chain. However, the selection of parameters for the molding process usually requires a huge effort to satisfy precious requirements of the molded optics and to avoid negative effects on the expensive tool molds. Therefore, to reduce experimental work at the beginning, a coupling CFD/FEM numerical modeling was developed to study the molding process. This research focuses on the development of a hybrid optimization approach in Non-isothermal glass molding. To this end, an optimal configuration with two optimization stages for multiple quality characteristics of the glass optics is addressed. The hybrid Back-Propagation Neural Network (BPNN)-Genetic Algorithm (GA) is first carried out to realize the optimal process parameters and the stability of the process. The second stage continues with the optimization of glass preform using those optimal parameters to guarantee the accuracy of the molded optics. Experiments are performed to evaluate the effectiveness and feasibility of the model for the process development in Non-isothermal glass molding.

  8. Study for Application of Slime- flocculate Dispersants%煤泥絮团分散剂的应用研究

    Institute of Scientific and Technical Information of China (English)

    戚冬伟; 宋玲玲; 冯莉; 蒋欧

    2011-01-01

    The author conducted dispersion experiments for Jiahe and Kailuan coal respectively, using sodium hexametaphosphate, sodium carboxymethyl cellulose (CMC) as dispersants. The dispersion effect was verified by viscosity of CWS, and the result of coal flotation after decentralization verified by the flotation experiment. The result~ showed that: both the dispersants had increased viscosities of the dispersions, reaching the purpose of dispersing sludge flocculate. After beins dispersed by sodium hexametaphosphate, both Jiahe and Kailuan clean coal ashes, recoveries were improved within a certain range, but had no regularity; because of the repulsion be- tween CMC and the collector, the clean coal was difficult to float out, though it had better dispersion. So it could not be used as slime - flocculate dispersants of flotation.%分别采用六偏磷酸钠、羧甲基纤维素钠(CMC)作为分散剂,对夹河煤、开滦煤进行分散试验,以自制水煤浆体系黏度大小为表征方法,验证其分散效果;并经由浮选实验结果验证分散处理之后的煤泥浮选效果。结果表明,两种分散剂均使各分散体系的黏度值有所增加,达到了分散煤泥絮团的目的。经六偏磷酸钠分散后,夹河煤和开滦煤的精煤灰分及回收率,在一定范围内均有所提高,但是规律性不强;CMC分散性很好,但因其与捕收剂之间具有排斥作用,难以浮选出精煤,不可用于煤泥浮选浆体分散。

  9. Investigations on injection molded, glass-fiber reinforced polyamide 6 integral foams using breathing mold technology

    Science.gov (United States)

    Roch, A.; Kehret, L.; Huber, T.; Henning, F.; Elsner, P.

    2015-05-01

    Investigations on PA6-GF50 integral foams have been carried out using different material systems: longfiber- and shortfiber-reinforced PA6 as well as unreinforced PA6 as a reference material. Both chemical and physical blowing agents were applied. Breathing mold technology (decompression of the mold) was selected for the foaming process. The integral foam design, which can be conceived as a sandwich structure, helps to save material in the neutral axis area and maintains a distance between load-bearing, unfoamed skin layers. For all test series an initial mold gap of 2.5 mm was chosen and the same amount of material was injected. In order to realize different density reductions, the mold opening stroke was varied. The experiments showed that, at a constant mass per unit area, integral polyamide 6 foams have a significantly higher bending stiffness than compact components, due to their higher area moment of inertia after foaming. At a constant surface weight the bending stiffness in these experiments could be increased by up to 600 %. Both shortfiber- and longfiber-reinforced polyamide 6 showed an increase in energy absorption during foaming.

  10. Injection-molded capsular device for oral pulsatile release: development of a novel mold.

    Science.gov (United States)

    Zema, Lucia; Loreti, Giulia; Macchi, Elena; Foppoli, Anastasia; Maroni, Alessandra; Gazzaniga, Andrea

    2013-02-01

    The development of a purposely devised mold and a newly set up injection molding (IM) manufacturing process was undertaken to prepare swellable/erodible hydroxypropyl cellulose-based capsular containers. When orally administered, such devices would be intended to achieve pulsatile and/or colonic time-dependent delivery of drugs. An in-depth evaluation of thermal, rheological, and mechanical characteristics of melt formulations/molded items made of the selected polymer (Klucel® LF) with increasing amounts of plasticizer (polyethylene glycol 1500, 5%-15% by weight) was preliminarily carried out. On the basis of the results obtained, a new mold was designed that allowed, through an automatic manufacturing cycle of 5 s duration, matching cap and body items to be prepared. These were subsequently filled and coupled to give a closed device of constant 600 μm thickness. As compared with previous IM systems having the same composition, such capsules showed improved closure mechanism, technological properties, especially in terms of reproducibility of the shell thickness, and release performance. Moreover, the ability of the capsular container to impart a constant lag phase before the liberation of the contents was demonstrated irrespective of the conveyed formulation.

  11. Mold Filling Analysis in Vacuum Infusion Molding Process Based on a High-Permeable Medium

    Institute of Scientific and Technical Information of China (English)

    Yingdan ZHU; Hua TAN; Jihui WANG

    2003-01-01

    The objective of this paper is to understand the flow mechanism through visualization experiments and discuss theinfluence of process parameters on mold filling process. A 2D leakage flow model is developed to simulate the moldingprocess, and the simulation results show good agreement with experiments.

  12. Study on Improving the Oxidation Efficiency of Lead Anode Slime%提高铅阳极泥氧化效率的研究

    Institute of Scientific and Technical Information of China (English)

    程永强

    2014-01-01

    影响铅阳极泥氧化的因素较多,本试验主要研究了温度及湿度对阳极泥氧化的影响。通过控制不同的温度和阳极泥含水量,对阳极泥氧化过程进行了监测。当温度在21~35℃范围时,阳极泥氧化速度较快,最佳的氧化温度为21~25℃。在采取保湿措施的同时,减少氧化过程中水分的蒸发,有利于阳极泥的氧化,最佳的湿度条件为阳极泥含水15%~25%。%T here are many influence factors in the oxidation of anode alime . T his test mainly studies the influence of temperature and humidity on the oxidation of anode slime . By controlling the different temperature and anode alime water content , the anode alime oxidation process is monitored . When the temperature is in the range of 21℃ to 35℃ , Anode slime oxidation speed is faster , the best oxidation temperature is 21℃ to 25℃ . As the same time of taking moisturizing measures , water evaporation is reduced in the oxidation process . This is good for the oxidation of anode slime;the best humidity condition is anode alime water content 15% to 25% .

  13. The flexible resin transfer molding (FRTM) process

    Science.gov (United States)

    Foley, Michael F.

    1992-12-01

    An innovative composite manufacturing process, FRTM, which is based on detailed cost analysis intended to be 'cost effective by design', is described. FRTM is based on a combination of the technical characteristics and respective favorable economics of diaphragm forming, and resin transfer molding. The process control system determines the optimal time for compaction and forming using an empirical resin polymerization model, a fluid flow model, and dielectric sensing of in-situ resin properties. The modified FRTM process is capable of producing high-quality parts with low thickness variation, low void content, and high fiber volume.

  14. TBS干扰床分选机对赵官能源粗煤泥分选效果技术研究%Study on the effect of separation technology of TBS interference bed separator of coarse slime Zhao Guan energy

    Institute of Scientific and Technical Information of China (English)

    赵建刚

    2015-01-01

    This paper introduces the factors of the structure and working principle, the inlfuence of TBS interference bed separator, and separation experiments of Zhaoguan energy coarse slime, analyzes the inlfuence of particle size of coarse slime interference bed separator separation effect, combined with energy Zhaoguan coal preparation process, give full play to the advantages of separation equipment, improve the accuracy of coarse slime separation.%该文介绍了TBS干扰床分选机的结构及工作原理、影响因素,并对赵官能源粗煤泥进行分选实验,分析了粗煤泥粒级对干扰床分选机分选效果的影响,结合赵官能源选煤工艺,充分发挥分选设备的优势,提高粗煤泥分选精度。

  15. Characteristics and infl uence factors of mold fi lling process in permanent mold with a slot gating system

    OpenAIRE

    2009-01-01

    The main problems caused by improper gating are entrained aluminum oxide fi lms and entrapped gas. In this study, the slot gating system is employed to improve mold fi lling behavior and therefore, to improve the quality of aluminum castings produced in permanent molds. An equipment as well as operation procedures for real-time X-ray radiography of molten aluminum fl owing into permanent molds have been developed. Graphite molds transparent to X-rays are utilized which make it possible to obs...

  16. Problem analysis and improvement measures of high coal slime water concentration%煤泥水浓度偏高原因分析及处理技术

    Institute of Scientific and Technical Information of China (English)

    宁石茂

    2014-01-01

    煤泥水浓度是影响脱介效果和精煤产品质量的重要因素,在指导分选生产中起着重要作用。以山西焦煤西山煤电屯兰选煤厂煤泥水浓度偏高情况为例,分析了高频筛回收效果差、絮凝剂添加不科学、浓缩机溢流大、重介系统筛板、筛篮跑粗等因素是影响煤泥水浓度偏大的主要原因。针对上述问题提出控制浓缩机溢流电流在280~310 A,絮凝剂配制成0.1%溶液;降低设备底煤厚度等技术方案。改造后,选煤厂煤泥水质量浓度低于13 g / L,提高产品产率,实现节能降耗,提高选煤厂的效率。%Coal slime water concentration was the main factor affecting the medium drainaging and clean coal quality,it also played impor-tant role in guiding flotation.In order to decrease the coal slime water concentration in Tunlan coal preparation plant,this paper analyzed the production flow.The results showed that,poor recycling effects of high frequency vibrating screen,unreasonable flocculant addition, large water from concentrated machine,leakage of coarse slime through the sieve plate and sieve basket of dense medium system were the main influencing factors.To resolve the above problems,the author prepared 0.1% flocculant by adjusting the electriccurrent of overflow ranging from 280 A to 310 A,decreased the equipment bottom coal thickness and other technical schemes.After transformation,the concen-tration of coal slime water was below 13 g/ L,the products yield were improved.The transformation saved the energy and decreased the pol-lutant emissions.

  17. Integrally cored ceramic investment casting mold fabricated by ceramic stereolithography

    Science.gov (United States)

    Bae, Chang-Jun

    Superalloy airfoils are produced by investment casting (IC), which uses ceramic cores and wax patterns with ceramic shell molds. Hollow cored superalloy airfoils in a gas turbine engine are an example of complex IC parts. The complex internal hollow cavities of the airfoil are designed to conduct cooling air through one or more passageways. These complex internal passageways have been fabricated by a lost wax process requiring several processing steps; core preparation, injection molding for wax pattern, and dipping process for ceramic shell molds. Several steps generate problems such as high cost and decreased accuracy of the ceramic mold. For example, costly tooling and production delay are required to produce mold dies for complex cores and wax patterns used in injection molding, resulting in a big obstacle for prototypes and smaller production runs. Rather than using separate cores, patterns, and shell molds, it would be advantageous to directly produce a mold that has the casting cavity and the ceramic core by one process. Ceramic stereolithography (CerSLA) can be used to directly fabricate the integrally cored ceramic casting mold (ICCM). CerSLA builds ceramic green objects from CAD files from many thin liquid layers of powder in monomer, which are solidified by polymerization with a UV laser, thereby "writing" the design for each slice. This dissertation addresses the integrally cored casting ceramic mold (ICCM), the ceramic core with a ceramic mold shell in a single patternless construction, fabricated by ceramic stereolithography (CerSLA). CerSLA is considered as an alternative method to replace lost wax processes, for small production runs or designs too complex for conventional cores and patterns. The main topic is the development of methods to successfully fabricate an ICCM by CerSLA from refractory silica, as well as related issues. The related issues are the segregation of coarse fused silica powders in a layer, the degree of segregation parameter to

  18. 浮选柱单独处理金矿矿泥的试验研究%Experimental study on processing of gold ore slime only using flotation columns

    Institute of Scientific and Technical Information of China (English)

    王攀志; 卞英娟; 姜浩刚

    2011-01-01

    The metal recovery is affected because there is more slime in the gold ore of Jiaojia Gold Mine. In order to study the influence of independent processing slime on recovery, the slime was treated separately. The pilot test for slime processed by flotation column is carried out. The influences of processing capacity, dosage of collector and frother are surveyed, and the flotation effects are contrasted. The results show that processing slime only using flotation column has obvious advantages than processing slime only using flotator, the recov ery rate improves by 10.02%. The study offers technical parameters for the second-stage extension.%焦家金矿处理的矿石含泥量多,影响金属回收.为探明单独处理矿泥对回收率的影响,对选矿工艺中的矿泥进行了浮选柱半工业试验,考察了处理量、捕收剂用量和起泡剂用量等因素的影响,并且与浮选机的浮选效果进行了比较.结果表明,单独采用浮选柱处理矿泥比单独用浮选机处理矿泥具有明显的优势,回收率提高了10.02%,经济效益显著,为二期扩建提供了技术参数.

  19. An Acrasin-Like Attractant from Yeast Extract Specific for Dictyostelium lacteum

    NARCIS (Netherlands)

    Mato, José M.; Haastert, Peter J.M. van; Krens, Frans A.; Konijn, Theo M.

    1977-01-01

    The transition of the unicellular to the multicellular stage in Dictyostelium lacteum is not mediated by cyclic AMP. The attractant for aggregative amoebae of this cellular slime mold species was isolated from yeast extract and purified more than 1000-fold without a significant loss of activity. Sev

  20. Developmental regulation of the Inositol 1,4,5-trisphosphate phosphatases in Dictyostelium discoideum

    NARCIS (Netherlands)

    Bominaar, Anthony A.; Dijken, Peter van; Draijer, Richard; Haastert, Peter J.M. van

    1991-01-01

    The cellular slime mold Dictyostelium discoideum is a microorganism in which growth and development are strictly separated. Starvation initiates a developmental program in which extracellular cAMP plays a major role as a signal molecule. In response to cAMP several second messengers are produced, in

  1. Isolation and Partial Characterization of a Cyclic GMP-Dependent Cyclic GMP-Specific Phosphodiesterase from Dictyostelium discoideum

    NARCIS (Netherlands)

    Bulgakov, Roman; Haastert, Peter J.M. van

    1983-01-01

    The cellular slime mold, Dictyostelium discoideum, contains at least two classes of phosphodiesterase activity. One class of enzymes hydrolyses cyclic AMP (cAMP) and cyclic GMP (cGMP) with approximately equal rates. Another enzyme, which is less than 5% of the total activity, specifically hydrolyses

  2. Cyclic nucleotide specificity of the activator and catalytic sites of a cGMP-stimulated cGMP phosphodiesterase from Dictyostelium discoideum

    NARCIS (Netherlands)

    Kesbeke, Fanja; Baraniak, Janina; Bulgakov, Roman; Jastorff, Bernd; Morr, Michael; Petridis, Georg; Stec, Wojciech J.; Seela, Frank; Haastert, Peter J.M. van

    1985-01-01

    The cellular slime mold Dictyostelium discoideum has an intracellular phosphodiesterase which specifically hydrolyzes cGMP. The enzyme is activated by low cGMP concentrations, and is involved in the reduction of chemoattractant-mediated elevations of cGMP levels. The interaction of 20 cGMP derivativ

  3. Antagonists of chemoattractants reveal separate receptors for cAMP, folic acid and pterin in Dictyostelium

    NARCIS (Netherlands)

    Haastert, Peter J.M. van; Wit, René J.W. de; Konijn, Theo M.

    1982-01-01

    Adenosine 3’,5’-monophosphate (cAMP), folic acid and pterin are chemoattractants in the cellular slime molds. The cAMP analog, 3’-amino-cAMP, inhibits a chemotactic reaction to cAMP at a concentration at which the analog is chemotactically inactive. The antagonistic effect of 3’-amino-cAMP on the ch

  4. Composite fabrication via resin transfer molding technology

    Energy Technology Data Exchange (ETDEWEB)

    Jamison, G.M.; Domeier, L.A.

    1996-04-01

    The IMPReS (Integrated Modeling and Processing of Resin-based Structures) Program was funded in FY95 to consolidate, evaluate and enhance Sandia`s capabilities in the design and fabrication of composite structures. A key driver of this and related programs was the need for more agile product development processes and for model based design and fabrication tools across all of Sandia`s material technologies. A team of polymer, composite and modeling personnel was assembled to benchmark Sandia`s existing expertise in this area relative to industrial and academic programs and to initiate the tasks required to meet Sandia`s future needs. RTM (Resin Transfer Molding) was selected as the focus composite fabrication technology due to its versatility and growing use in industry. Modeling efforts focused on the prediction of composite mechanical properties and failure/damage mechanisms and also on the uncured resin flow processes typical of RTM. Appropriate molds and test composites were fabricated and model validation studies begun. This report summarizes and archives the modeling and fabrication studies carried out under IMPReS and evaluates the status of composite technology within Sandia. It should provide a complete and convenient baseline for future composite technology efforts within Sandia.

  5. Rotational molding of bio-polymers

    Science.gov (United States)

    Greco, Antonio; Maffezzoli, Alfonso; Forleo, Stefania

    2014-05-01

    This paper is aimed to study the suitability of bio-polymers, including poly-lactic acid (PLLA) and Mater-Bi, for the production of hollow components by rotational molding. In order to reduce the brittleness of PLLA, the material was mixed with two different plasticizers, bis-ethyl-hexyl-phthalate (DEHP) and poly-ethylene-glycol (PEG). The materials were characterized in terms of sinterability. To this purpose, thermomechanical (TMA) analysis was performed at different heating rates, in order to identify the endset temperatures of densification and the onset temperatures of degradation. Results obtained indicated that the materials are characterized by a very fast sintering process, occurring just above the melting temperature, and an adequately high onset of degradation. The difference between the onset of degradation and the endset of sintering, defined as the processing window of the polymer, is sufficiently wide, indicating that the polymers can be efficiently processed by rotational molding. Therefore, a laboratory scale apparatus was used for the production of PLLA and Mater-Bi prototypes. The materials were processed using very similar conditions to those used for LLDPE. The production of void-free samples of uniform wall thickness was considered as an indication of the potentiality of the process for the production of biodegradable containers.

  6. Production of Liquid Metal Spheres by Molding

    Directory of Open Access Journals (Sweden)

    Mohammed G. Mohammed

    2014-10-01

    Full Text Available This paper demonstrates a molding technique for producing spheres composed of eutectic gallium-indium (EGaIn with diameters ranging from hundreds of microns to a couple millimeters. The technique starts by spreading EGaIn across an elastomeric sheet featuring cylindrical reservoirs defined by replica molding. The metal flows into these features during spreading. The spontaneous formation of a thin oxide layer on the liquid metal keeps the metal flush inside these reservoirs. Subsequent exposure to acid removes the oxide and causes the metal to bead up into a sphere with a size dictated by the volume of the reservoirs. This technique allows for the production and patterning of droplets with a wide range of volumes, from tens of nanoliters up to a few microliters. EGaIn spheres can be embedded or encased subsequently in polymer matrices using this technique. These spheres may be useful as solder bumps, electrodes, thermal contacts or components in microfluidic devices (valves, switches, pumps. The ease of parallel-processing and the ability to control the location of the droplets during their formation distinguishes this technique.

  7. Lighting molded optics: Design and manufacturing

    Directory of Open Access Journals (Sweden)

    Kočárková H.

    2013-05-01

    Full Text Available Proper design and manufacturing of glass molded lenses need to be performed in several steps. The whole process from customer requirements to f nal functional product is shown on two examples - a lens for street light and a lens for spot light with narrow lighting angle. After discussing customer requirements, optical design is made. Thanks to various commercial softwares with optimization, manufacturer of the lens can work as well as a designer which enables simplif cation and acceleration of lens manufacturing, since limitations of the manufacturing process are considered during creation of the design. When the prototype is made, its functionality needs to be evaluated. This work shows measurement of light distribution for street light lens in a dark room using goniometer and measurement of light intensity for spot lens f xed on an optical bench. These measurements can reveal the root cause in case of lens malfunction, which enables to optimize manufacturing process or modify lens design accordingly. Designing, manufacturing and evaluation of molded optics under one roof enables creation of easily manufacturable design and fast solution of problems.

  8. Sinterability of Zirconia Top Coat of Investment Mold for Ti Alloy

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    In this paper, zirconia is used as top mold material for Ti investment casting. Top mold samples are made by proper mold building technology. The effect of different sintering temperature on chemical composition, microstructure and residual bending strength of the top mold sample is studied. The volume and homogeneity of the air holes in the top mold are determined by sintering temperature, and finally determined the residual bending strength of the mold sample was determined.

  9. Development of the computer-aided process planning (CAPP) system for polymer injection molds manufacturing

    OpenAIRE

    J. Tepić; V. Todić; Lukić, D.; Milošević, M.; Borojević, S.

    2011-01-01

    Beginning of production and selling of polymer products largely depends on mold manufacturing. The costs of mold manufacturing have significant share in the final price of a product. The best way to improve and rationalize polymer injection molds production process is by doing mold design automation and manufacturing process planning automation. This paper reviews development of a dedicated process planning system for manufacturing of the mold for injection molding, which integrates computer-...

  10. Mycotoxins and Antifungal Drug Interactions: Implications in the Treatment of Illnesses Due to Indoor Chronic Toxigenic Mold Exposures

    Directory of Open Access Journals (Sweden)

    Ebere C. Anyanwu

    2004-01-01

    Full Text Available Chronic exposure to toxigenic molds in water-damaged buildings is an indoor environmental health problem to which escalating health and property insurance costs are raising a statewide concern in recent times. This paper reviews the structural and functional properties of mycotoxins produced by toxigenic molds and their interactive health implications with antifungal drugs. Fundamental bases of pathophysiological, neurodevelopmental, and cellular mechanisms of mycotoxic effects are evaluated. It is most likely that the interactions of mycotoxins with antifungal drugs may, at least in part, contribute to the observable persistent illnesses, antifungal drug resistance, and allergic reactions in patients exposed to chronic toxigenic molds. Safe dose level of mycotoxin in humans is not clear. Hence, the safety regulations in place at the moment remain inconclusive, precautionary, and arbitrary. Since some of the antifungal drugs are derived from molds, and since they have structural and functional groups similar to those of mycotoxins, the knowledge of their interactions are important in enhancing preventive measures.

  11. Optimization of Mold Yield in MultiCavity Sand Castings

    Science.gov (United States)

    Shinde, Vasudev D.; Joshi, Durgesh; Ravi, B.; Narasimhan, K.

    2013-06-01

    The productivity of ductile iron foundries engaging in mass production of castings for the automobile and other engineering sectors depends on the number of cavities per mold. A denser packing of cavities, however, results in slower heat transfer from adjacent cavities, leading to delayed solidification, possible shrinkage defects, and lower mechanical properties. In this article, we propose a methodology to optimize mold yield by selecting the correct combination of the mold box size and the number of cavities based on solidification time and mold temperature. Simulation studies were carried out by modeling solid and hollow cube castings with different values of cavity-wall gap and finding the minimum value of the gap beyond which there is no change in casting solidification time. Then double-cavity molds were modeled with different values of cavity-cavity gap, and simulated to find the minimum value of gap. The simulation results were verified by melting and pouring ductile iron in green sand molds instrumented with thermocouples, and recording the temperature in mold at predetermined locations. The proposed approach can be employed to generate a technological database of minimum gaps for various combinations of part geometry, metal and process, which will be very useful to optimize the mold cavity layouts.

  12. Vacuum Infusion Molding Process (Part 2 VIMP Based on Grooves)

    Institute of Scientific and Technical Information of China (English)

    ZHU Ying-dan; DENG Jing-lan; WANG Ji-hui; TAN Hua

    2003-01-01

    The optimal parameters for flow grooves and supply grooves were determined by a series of experiments , and the influences of various molding conditions on the mold filling process were analyzed. Furthermore ,the whole VIMP procedure based on grooves was introduced in detail taking the manufacture of a sandwich panel as an example.

  13. A fabrication method of microneedle molds with controlled microstructures.

    Science.gov (United States)

    Wang, Qi Lei; Zhu, Dan Dan; Chen, Yang; Guo, Xin Dong

    2016-08-01

    Microneedle (MN) offers an attractive, painless and minimally invasive approach for transdermal drug delivery. Polymer microneedles are normally fabricated by using the micromolding method employing a MN mold, which is suitable for mass production due to high production efficiency and repeat-using of the mold. Most of the MN molds are prepared by pouring sylgard polymer over a MN master to make an inverse one after curing, which is limited in optimizing or controlling the MN structures and failing to keep the sharpness of MNs. In this work we describe a fabrication method of MN mold with controlled microstructures, which is meaningful for the fabrication of polymer MNs with different geometries. Laser micro-machining method was employed to drill on the surface of PDMS sheets to obtain MN molds. In the fabrication process, the microstructures of MN molds are precisely controlled by changing laser parameters and imported patterns. The MNs prepared from these molds are sharp enough to penetrate the skin. This scalable MN mold fabrication method is helpful for future applications of MNs.

  14. Two component micro injection molding for MID fabrication

    DEFF Research Database (Denmark)

    Islam, Mohammad Aminul; Hansen, Hans Nørgaard; Tang, Peter Torben

    2009-01-01

    Molded Interconnect Devices (MIDs) are plastic substrates with electrical infrastructure. The fabrication of MIDs is usually based on injection molding and different process chains may be identified from this starting point. The use of MIDs has been driven primarily by the automotive sector, but ...

  15. ASTHMATIC HUMAN SERUM IGE-REACTIVITY WITH MOLD EXTRACTS

    Science.gov (United States)

    Although molds have demonstrated the ability to induce allergic asthma-like responses in mouse models, their role in human disease is unclear. This study was undertaken to provide insight into the prevalence of human IgE-reactivity and identify the target mold protein(s). The st...

  16. IGE IN ASTHMATIC HUMAN SERA IS REACTIVE AGAINST MOLD EXTRACTS

    Science.gov (United States)

    Molds have been associated with various health effects including asthma, but their role in induction of asthma is unclear. However, the presence of mold-specific IgE indicates their capacity to induce allergic responses and possibly exacerbate asthma symptoms. This study was und...

  17. 21 CFR 177.2410 - Phenolic resins in molded articles.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Phenolic resins in molded articles. 177.2410... as Components of Articles Intended for Repeated Use § 177.2410 Phenolic resins in molded articles. Phenolic resins identified in this section may be safely used as the food-contact surface of...

  18. Effect of processing conditions on shrinkage in injection molding

    NARCIS (Netherlands)

    Jansen, K.M.B.; Dijk, van D.J.; Husselman, M.H.

    1998-01-01

    A systematic study on the effect of processing conditions on mold shrinkage was undertaken for seven common thermoplastic polymers. It turned out that the holding pressure was always the key parameter. The effect of the melt temperature is slightly less important. Injection velocity and mold tempera

  19. Multi-height structures in injection molded polymer

    DEFF Research Database (Denmark)

    Andersen, Nis Korsgaard; Taboryski, Rafael J.

    2015-01-01

    We present the fabrication process for injection molded multi-height surface structures for studies of wetting behavior. We adapt the design of super hydrophobic structures to the fabrication constrictions imposed by industrial injection molding. This is important since many super hydrophobic sur...

  20. Taxonomic re-evaluation of black koji molds

    NARCIS (Netherlands)

    Hong, S.B.; Yamada, O.; Samson, R.A.

    2013-01-01

    Black koji molds including its albino mutant, the white koji mold, have been widely used for making the distilled spirit shochu in Northeast Asia because they produce citric acid which prevents undesirable contamination from bacteria. Since Inui reported Aspergillus luchuensis from black koji in Oki

  1. Standard Molded Composite Rocket Pyrogen Igniter - A progress report

    Science.gov (United States)

    Lucy, M. H.

    1978-01-01

    The pyrogen igniter has the function to furnish a controlled, high temperature, high pressure gas to ignite solid propellant surfaces in a rocket motor. Present pyrogens consist of numerous inert components. The Standard Molded Pyrogen Igniter (SMPI) consists of three basic parts, a cap with several integrally molded features, an ignition pellet retainer plate, and a tube with additional integrally molded features. A description is presented of an investigation which indicates that the SMPI concept is a viable approach to the design and manufacture of pyrogen igniters for solid propellant rocket motors. For some applications, combining the structural and thermal properties of molded composites can result in the manufacture of lighter assemblies at considerable cost reduction. It is demonstrated that high strength, thin walled tubes with high length to diameter ratios can be fabricated from reinforced plastic molding compound using the displacement compression process.

  2. THE DURABILITY OF LARGE-SCALE ADDITIVE MANUFACTURING COMPOSITE MOLDS

    Energy Technology Data Exchange (ETDEWEB)

    Post, Brian K [ORNL; Love, Lonnie J [ORNL; Duty, Chad [University of Tennessee (UTK) and Oak Ridge National Laboratory (ORNL); Vaidya, Uday [University of Tennessee, Knoxville (UTK); Pipes, R. Byron [Purdue University; Kunc, Vlastimil [ORNL

    2016-01-01

    Oak Ridge National Laboratory s Big Area Additive Manufacturing (BAAM) technology permits the rapid production of thermoplastic composite molds using a carbon fiber filled Acrylonitrile-Butadiene-Styrene (ABS) thermoplastic. Demonstration tools (i.e. 0.965 m X 0.559 m X 0.152 m) for composite part fabrication have been printed, coated, and finished with a traditional tooling gel. We present validation results demonstrating the stability of thermoplastic printed molds for room temperature Vacuum Assisted Resin Transfer Molding (VARTM) processes. Arkema s Elium thermoplastic resin was investigated with a variety of reinforcement materials. Experimental results include dimensional characterization of the tool surface using laser scanning technique following demolding of 10 parts. Thermoplastic composite molds offer rapid production compared to traditionally built thermoset molds in that near-net deposition allows direct digital production of the net geometry at production rate of 45 kg/hr.

  3. Injection molding of bushes made of tribological PEEK composites

    Directory of Open Access Journals (Sweden)

    2007-12-01

    Full Text Available Polyetheretherketone (PEEK composites have been extensively studied because of the excellent tribological behavior among plastics. However, laboratory specimens and tests are generally discussed, whereas application studies on industrial components are infrequent. In this paper, an injection molded bush made of tribological PEEK was analyzed to correlate wear behavior and molded material structure. Bushes were tested under unlubricated sliding conditions by means of a short wear test. Surface analysis, differential scanning calorimetry (DSC and optical microscopy were used to evaluate the distribution of the different composite fillers (polytetrafluoroethylene, PTFE, graphite particles and carbon microfibers and their effect on the final bush behavior. A significant lack of homogeneity was observed in the molded bush and black bands appeared on the shaft surface after testing due to the sliding. The bush geometry and the injection molding process should be optimized to allow the best tribological behavior of the molded material under working conditions.

  4. Injection-molded nanocomposites and materials based on wheat gluten.

    Science.gov (United States)

    Cho, S-W; Gällstedt, M; Johansson, E; Hedenqvist, M S

    2011-01-01

    This is, to our knowledge, the first study of the injection molding of materials where wheat gluten (WG) is the main component. In addition to a plasticizer (glycerol), 5 wt.% natural montmorillonite clay was added. X-ray indicated intercalated clay and transmission electron microscopy indicated locally good clay platelet dispersion. Prior to feeding into the injection molder, the material was first compression molded into plates and pelletized. The filling of the circular mold via the central gate was characterized by a divergent flow yielding, in general, a stronger and stiffer material in the circumferential direction. It was observed that 20-30 wt.% glycerol yielded the best combination of processability and mechanical properties. The clay yielded improved processability, plate homogeneity and tensile stiffness. IR spectroscopy and protein solubility indicated that the injection molding process yielded a highly aggregated structure. The overall conclusion was that injection molding is a very promising method for producing WG objects.

  5. Mold Flora of Traditional Cheeses Produced in Turkey

    Directory of Open Access Journals (Sweden)

    Musa Yalman

    2016-11-01

    Full Text Available In our country, there are many cheese types that are produced traditionally. Cheeses which produced from cows, sheep and goat milk that matured with spontaneous growth of molds present in livestock skins, pots and similar environments are among them. They are produced traditionally in Mediterrian, Central and Eastern Anatolia regions. Molds that grow spontaneously in cheeses could create public health risk because of their secondary metabolites. Penicillium spp. are the most isolated mold from these cheeses and Penicillium roqueforti is determined as the dominant species. Furthermore, Aspergillus, Alternaria, Mucor, Geotrichum, Cladosporium species have been isolated. It is very important to control the ripening conditions and starter strain selection since some strains were reported as mycotoxin producers. In this review, it has been tried to give general information about traditional production of mold-ripened cheese in Turkey and the mold flora found in traditional cheeses. In addition, public health risk of these cheeses is reported.

  6. The Facility and Process Technics of Polyethylene Rotational Molding

    Institute of Scientific and Technical Information of China (English)

    LI; BaiShun

    2001-01-01

    1. Introduction Rotational molding is the process by which hollow plastic parts are formed. It mainly processes the product which Injection molding and Blow molding can not process medium-sized, large-sized and super large-sized plastic parts. The technics may turn out a tub, dustbin, stock tank, sailboat.  The research institute of Lanzhou introduces a suit of RS-16 Rotational Molding Machine from Germany Reinhadt Co. on 1990. It mainly put up experiment and smallscale production. RS-16 rotational molding machine is a single arm and di-axial equipment. It is consisting of a gas heated sintering oven, cooling chamber, mouldcarrying carriage and a controlling unit.  ……

  7. Mathematical modeling of the in-mold coating process for injection-molded thermoplastic parts

    Science.gov (United States)

    Chen, Xu

    In-Mold Coating (IMC) has been successfully used for many years for exterior body panels made from compression molded Sheet Molding Compound (SMC). The coating material is a single component reactive fluid, designed to improve the surface quality of SMC moldings in terms of functional and cosmetic properties. When injected onto a cured SMC part, IMC cures and bonds to provide a pain-like surface. Because of its distinct advantages, IMC is being considered for application to injection molded thermoplastic parts. For a successful in mold coating operation, there are two key issues related to the flow of the coating. First, the injection nozzle should be located such that the thermoplastic substrate is totally covered and the potential for air trapping is minimized. The selected location should be cosmetically acceptable since it most likely will leave a mark on the coated surface. The nozzle location also needs to be accessible for easy of maintenance. Secondly, the hydraulic force generated by the coating injection pressure should not exceed the available clamping tonnage. If the clamping force is exceeded, coating leakage will occur. In this study, mathematical models for IMC flow on the compressible thermoplastic substrate have been developed. Finite Difference Method (FDM) is first used to solve the 1 dimensional (1D) IMC flow problem. In order to investigate the application of Control Volume based Finite Element Method (CV/FEM) to more complicated two dimensional IMC flow, that method is first evaluated by solving the 1D IMC flow problem. An analytical solution, which can be obtained when a linear relationship between the coating thickness and coating injection pressure is assumed, is used to verify the numerical results. The mathematical models for the 2 dimensional (2D) IMC flow are based on the generalized Hele-Shaw approximation. It has been found experimentally that the power law viscosity model adequately predicts the rheological behavior of the coating

  8. Public health and economic impact of dampness and mold

    Energy Technology Data Exchange (ETDEWEB)

    Mudarri, David; Fisk, William J.

    2007-06-01

    The public health risk and economic impact of dampness and mold exposures was assessed using current asthma as a health endpoint. Individual risk of current asthma from exposure to dampness and mold in homes from Fisk et al. (2007), and asthma risks calculated from additional studies that reported the prevalence of dampness and mold in homes were used to estimate the proportion of U.S. current asthma cases that are attributable to dampness and mold exposure at 21% (95% confidence internal 12-29%). An examination of the literature covering dampness and mold in schools, offices, and institutional buildings, which is summarized in the appendix, suggests that risks from exposure in these buildings are similar to risks from exposures in homes. Of the 21.8 million people reported to have asthma in the U.S., approximately 4.6 (2.7-6.3) million cases are estimated to be attributable to dampness and mold exposure in the home. Estimates of the national cost of asthma from two prior studies were updated to 2004 and used to estimate the economic impact of dampness and mold exposures. By applying the attributable fraction to the updated national annual cost of asthma, the national annual cost of asthma that is attributable to dampness and mold exposure in the home is estimated to be $3.5 billion ($2.1-4.8 billion). Analysis indicates that exposure to dampness and mold in buildings poses significant public health and economic risks in the U.S. These findings are compatible with public policies and programs that help control moisture and mold in buildings.

  9. CENTRAL CONVEYING & AUTO FEEDING SYSTEMS FOR AN INJECTION MOLDING SHOP

    Directory of Open Access Journals (Sweden)

    Sanjeev Kumar

    2011-08-01

    Full Text Available Nowadays injection molding is probably the most important method of Processing of consumer and industrial goods, and is performed everywhere in the world. The developing of injection molding becomes a competition from day to day. This Process now integrated with computer control make the production better in quality and Better quantity. The trends of producing a plastics product in injection molding industries are recently changing from traditional method to using the FEA analysis. For injection molding industries, time and cost is very important aspects to consider because these two aspectswill directly related to the profits at a company. The next issue toconsider, to get the best parameter for the injection molding process, plastics has been waste. Through the experiment, operator will use large amount of plastics material to get the possibly parameters to setup the machine.To produce the parts with better quality and quantity these molding defects are the major obstacles in achieving the targets with quality & quantity. Various defects like Short shot, colour streaks and low productivity rates are associated with the material mixing and feeding as molded plastics are often a blend of two or more materials. Colors (master batch and other additives are often mixed (blended with the raw plastic material prior to the molding process in molding plants. So it is very necessary to work out auto blending and auto feeding of plasticgranules to the machine hopper. This paper will cover the studyof automatic blending unit & central conveying system for plasticgranule feeding to machine & will help in optimizing the injection molding process.

  10. Research on coarse slime separation equipment and process%粗煤泥分选设备及分选工艺研究

    Institute of Scientific and Technical Information of China (English)

    韩恒旺; 李炳才; 訾涛; 刘世理; 鲁合德

    2011-01-01

    通过对粗煤泥分选设备分选原理、结构特点及工艺特点分析,证明了影响设备分选效果的主要因素是上游的分级设备.结合梁北选煤厂生产实际,根据TBS的等沉比分选原理,提出了TBS分级粗煤泥中高灰细泥的设想并进行了相关试验研究.结果表明:TBS可作为高灰细泥的分级设备,解决了粗煤泥分选的难题.%According to analyzing separation principle, structural and process characteristics of coarse slime separation equipment,draw the conclusion that classified equipment is the major factor which influences separation effect. Combining practical production and TBS equal setting ratio separation principle, the method of separating high ash content fine mud from coarse slime with TBS is put forward.

  11. Dicty_cDB: Contig-U15420-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available dd-... 194 e-104 3 ( K03066 ) Slime mold (D.discoideum) mRNA complementary to two... 287 2e-96 3 ( K03070 ) ...e mold (D.discoideum) heat-shock promoter in DI... 64 1e-05 1 ( K03064 ) Slime mold (D.discoideum) mRNA complementary...2 5 ( K03067 ) Slime mold (D.discoideum) DIRS-1 left inverted term... 96 7e-79 6 ( K03073 ) Slime mold (D.discoideum) mRNA complement...ary to the... 184 6e-73 2 ( K03071 ) Slime mold (D.discoideum) DIRS-1 left inverted

  12. Specific mold filling characteristics of highly filled phenolic injection molding compounds

    OpenAIRE

    Scheffler, Thomas; Englich, Sascha; Gehde, Michael

    2016-01-01

    Thermosets show excellent mechanical properties and chemical resistance (for most automotive fluids) even at high temperatures up to 300 °C. Furthermore they can be highly efficient processed by injection molding. So they should be particularly suited for e.g. under the bonnet applications. However, the reality shows that thermosets are, except fiber reinforced composites, heavily underrepresented in technical applications. E.g. thermosetting components only account 0,2 % to a vehicle’s weigh...

  13. IMAGE ANALYSIS DEDICATED TO POLYMER INJECTION MOLDING

    Directory of Open Access Journals (Sweden)

    David Garcia

    2011-05-01

    Full Text Available This work follows the general framework of polymer injection moulding simulation whose objectives are the mastering of the injection moulding process. The models of numerical simulation make it possible to predict the propagation of the molten polymer during the filling phase from the positioning of one point of injection or more. The objective of this paper is to propose a particular way to optimize the geometry of mold cavity in accordance with physical laws. A direct correlation is pointed out between geometric parameters issued from skeleton transformation and Hausdorff's distance and results provided by implementation of a classical model based on the Hele-Shaw equations which are currently used in the main computer codes of polymer injection.

  14. [Biological monitoring in the molding of plastics and rubbers].

    Science.gov (United States)

    Fustinoni, S; Campo, L; Cirla, A M; Cirla, P E; Cutugno, V; Lionetti, C; Martinotti, I; Mossini, E; Foà, V

    2007-01-01

    This survey was carried out in the molding of plastics and rubbers, in the "Professional Cancer Prevention Project" sponsored by the Lombardy region with the objective of developing and implementing protocols for evaluating exposure to carcinogens through the biological monitoring. The realities of molding the thermoplastic polymer ABS, rubber, and thermosetting plastics containing formaldehyde were examined. The carcinogenic substances identified in these processes were: 1,3-butadiene, acrylonitrile and styrene in molding ABS, polycyclic aromatic hydrocarbons (PAH) in molding rubber, and formaldehyde in molding the thermosetting plastics. Only for some of these substances biological indicators are available. The limited exposure to airborne chemicals in molding ABS and the intrinsic characteristics of biological indicators available for 1-3 butadiene have determined the non applicability of biological monitoring to this situation. The absence of a biological indicator of exposure to formaldehyde has made this situation not investigable. Exposure in the rubber molding was studied in 19 subjects applying the determination not metabolized PAH in urine. The levels of these indicators were similar to those measured in other groups of subjects without occupational exposure to PAH, confirming a low airborne contamination in this workplace.

  15. Thermomechanical Behavior in Continuous Bloom Casting with Different Mold Tapers

    Institute of Scientific and Technical Information of China (English)

    LUO Xin; CHEN Yong; SHEN Houfa

    2008-01-01

    A two-dimensional finite element model was used to analyze the thermal and mechanical behavior dunng solidification of the strand in a continuous bloom casting mold.The coupled heat transfer and defermation were analyzed to simulate the formation of the air gap between the mold and the strand.The model was used to investigate the influence of mold taper on the temperature and stress distributions in the strand.The results show that the air gap mainly forms around the strand corner,causing a hoRer and thinner solidifying shell in this region.The mold taper partially compensates for the strand shell shnnkage and reduces the infiuence of the air gap on the heat transfer.The mold taper compresses the shell and changes the stress state around the stmnd comer region.As the strand moves down into the mold,the mold constraint causes compressive stress beneath the comer surface.which reduces the hot tear that forms on the strand.

  16. Review of small aspheric glass lens molding technologies

    Science.gov (United States)

    Yin, Shaohui; Jia, Hongpeng; Zhang, Guanhua; Chen, Fengjun; Zhu, Kejun

    2017-01-01

    Aspheric lens can eliminate spherical aberrations, coma, astigmatism, field distortions, and other adverse factors. This type of lens can also reduce the loss of light energy and obtain high-quality images and optical characteristics. The demand for aspheric lens has increased in recent years because of its advantageous use in the electronics industry, particularly for compact, portable devices and high-performance products. As an advanced manufacturing technology, the glass lens molding process has been recognized as a low-cost and high-efficiency manufacturing technology for machining small-diameter aspheric lens for industrial production. However, the residual stress and profile deviation of the glass lens are greatly affected by various key technologies for glass lens molding, including glass and mold-die material forming, mold-die machining, and lens molding. These key technical factors, which affect the quality of the glass lens molding process, are systematically discussed and reviewed to solve the existing technical bottlenecks and problems, as well as to predict the potential applicability of glass lens molding in the future.

  17. A New Type Machine of Mixing-molding for Polyblends

    Institute of Scientific and Technical Information of China (English)

    WANG Chuan-sheng; LI Li; BIAN Hui-guang

    2009-01-01

    This paper introduces a new type machine for polyblends with excellent mixing capabilities of internal mixer and continuous molding character of extruder. The machine includes two functions -- mixing and extrusion molding that have been composed together by rational design, so a tandem production mode -- "batch + continuous" are opened up. The mathematical model of continuous mixing molding was established and verified availably by experimental research. The main physical mechanical property of vuicanizate, which had met national waterproof material standard, verified the machine practicability. The essential difference from other similar type machines is that this machine is not only suitable in producing granular and powder rubbers but also lumpish tablets.

  18. Desarrollo de moldes de prensado con recubrimientos antidesgaste

    OpenAIRE

    Poyatos, A.; Tur, F.; Pérez, José Antonio; Rodríguez, Miguel A.

    2005-01-01

    [ES] El objetivo del presente trabajo ha sido el desarrollo de una nueva concepción de moldes de prensado para la industria del pavimento y revestimiento cerámicos. El empleo de recubrimientos con materiales compuestos metal-cerámica ha permitido, además de multiplicar la vida útil de los moldes por un factor entre 2 y 3 (1.000.000 – 1.500.000 ciclos de prensado), emplear aceros más económicos en la producción del molde, su reutilización, eliminar etapas de alto consumo energético, c...

  19. Development of Integrated Simulation System for Plastic Injection Molding

    Institute of Scientific and Technical Information of China (English)

    CHENGXue-wen; LIDe-qun; ZHOUHua-min

    2005-01-01

    Numerical simulation of injection molding have had success in predicting the behavior of polymer melt in extremely complicated geometries. Most of the current numerical solutions are based on finite-element/finite-difference/boundary-element/volume-control methods and the surface model. This paper discusses the development of an integrated CAE system for injection molding in detail, and presents the mathematics for numerical simulation of filling, packing,cooling, stress and warpage in injection molding. The developed system named as HsCAE3D is introduced at the end.

  20. The analysis of injection molding defects caused by gate vestiges

    Directory of Open Access Journals (Sweden)

    T. Tabi

    2015-04-01

    Full Text Available Issues of product safety are the most serious problems of an injection molded product due to their risk to human health. Such a safety problem can be the needle-shaped vestige at the gate zone of injection molded products, called a gate vestige. Only observations of the formation of gate vestiges can be found in the literature, but the processing parameters influencing their dimensions, especially their height have not been studied yet. Our goal was to study the effect of various injection molding processing parameters and gate constructions on gate vestige formation.

  1. Recent Developments and Trends in Powder Injection Molding

    Institute of Scientific and Technical Information of China (English)

    Hermina Wang

    2000-01-01

    Injection molding is a productive and widely used technology for shaping plastics. The use of this shaping technique to metal and ceramics powders is termed powder injection molding (PIM). This process combines a certain quantity of a polymer with a metallic or ceramic powder to form a feedstock that can be molded. After shaping, the polymeric binder is extracted and the powder is sintered. When proper powder size or/and its distribution are used, sintered densities of 95% or more, often to near-theoretical densities, are reached and the mechanical properties are, therefore, generally superior to those of traditional PM parts.

  2. Fabrication of micro gear wheels by micropowder injection molding

    Institute of Scientific and Technical Information of China (English)

    Haiqing Yin; Xuanhui Qu; Chengchang Jia

    2008-01-01

    The micropowder injection molding technology was investigated to fabricate the microsized gear wheels on a conventional injection molding machine. The feedstock comprised of carbonyl ferrum powder and a wax-based thermoplastic binder. Microinjection molding was fulfilled at about 423 K under 100 MPa. The heating system was applied to the die to improve the fluidity of the feedstock and subsequently the cooling system was used to enhance the strength of the green compacts after injection by decreasing the temperature of the die. The gear wheels were realized successfully with their addendum circle diameter ranging from 800 to 200 m and with the center hole as small as 60 μtm.

  3. Rapid and low-cost prototyping of medical devices using 3D printed molds for liquid injection molding.

    Science.gov (United States)

    Chung, Philip; Heller, J Alex; Etemadi, Mozziyar; Ottoson, Paige E; Liu, Jonathan A; Rand, Larry; Roy, Shuvo

    2014-06-27

    Biologically inert elastomers such as silicone are favorable materials for medical device fabrication, but forming and curing these elastomers using traditional liquid injection molding processes can be an expensive process due to tooling and equipment costs. As a result, it has traditionally been impractical to use liquid injection molding for low-cost, rapid prototyping applications. We have devised a method for rapid and low-cost production of liquid elastomer injection molded devices that utilizes fused deposition modeling 3D printers for mold design and a modified desiccator as an injection system. Low costs and rapid turnaround time in this technique lower the barrier to iteratively designing and prototyping complex elastomer devices. Furthermore, CAD models developed in this process can be later adapted for metal mold tooling design, enabling an easy transition to a traditional injection molding process. We have used this technique to manufacture intravaginal probes involving complex geometries, as well as overmolding over metal parts, using tools commonly available within an academic research laboratory. However, this technique can be easily adapted to create liquid injection molded devices for many other applications.

  4. 40 CFR 63.5728 - What standards must I meet for closed molding resin operations?

    Science.gov (United States)

    2010-07-01

    ... molding resin operations? 63.5728 Section 63.5728 Protection of Environment ENVIRONMENTAL PROTECTION... Standards for Closed Molding Resin Operations § 63.5728 What standards must I meet for closed molding resin operations? (a) If a resin application operation meets the definition of closed molding specified in §...

  5. The use of birefringence for predicting the stiffness of injection molded polycarbonate discs

    NARCIS (Netherlands)

    Neves, N.M.; Pouzada, A.S.; Voerman, J.H.D.; Powell, P.C.

    1998-01-01

    Polycarbonate discs were injection molded with different sets of molding conditions. The parameters studied were the flow rate, melt- and mold-temperature. The discs were subjected to three point support flexural tests. Those tests are specially intended for injection molded discs because of their i

  6. Mold Simulator Study on the Initial Solidification of Molten Steel Near the Corner of Continuous Casting Mold

    Science.gov (United States)

    Lyu, Peisheng; Wang, Wanlin; Zhang, Haihui

    2016-11-01

    Corner cracks are one of the most widespread surface defects of continuous casting slabs, and they are especially severe for peritectic steels and low-alloy steels. Therefore, a clear understanding of molten steel initial solidification around mold corner would be of great importance for the inhibition of corner cracks. This paper has been conducted with the aim to elucidate this understanding, by using a novel mold simulator equipped with a right-angle copper mold. The responding temperatures and heat fluxes across the mold hot-face and corner were firstly calculated through a 2D-inverse heat conduction program mathematical model, and the results suggested that the cooling ability and the fluctuation of heat fluxes around the mold corner are stronger than those for mold hot-face. With the help of power spectral density analysis and fast Fourier transformation, the four characteristic signals of heat fluxes were discussed in this paper. Next, the relation between the thickness of solidified shell and solidification time was fitted with the solidification square root law; as a result, the average solidification factor bar{K} for the hot-face shell is 2.32 mm/s1/2, and it is 2.77 mm/s1/2 for the shell near-corner. For the same oscillation marks (OMs), it appeared that the OMs positions on the shell corner are lower than those on the shell hot-face along the casting direction, because the stronger shrinkage of shell at the corner allows the overflowing steel to penetrate deeper into the larger gap between the shell corner and mold, which is demonstrated through the heat transfer analysis and metallographic examination. Finally, the interrelation between shell profile, mold oscillation, variation rate of heat flux, high-frequency heat flux and high-frequency temperature was discussed for above two cases, and the results suggested that meniscus conditions (heat transfer and melt flow) around the mold corner are more unsteady.

  7. Mold Simulator Study on the Initial Solidification of Molten Steel Near the Corner of Continuous Casting Mold

    Science.gov (United States)

    Lyu, Peisheng; Wang, Wanlin; Zhang, Haihui

    2017-02-01

    Corner cracks are one of the most widespread surface defects of continuous casting slabs, and they are especially severe for peritectic steels and low-alloy steels. Therefore, a clear understanding of molten steel initial solidification around mold corner would be of great importance for the inhibition of corner cracks. This paper has been conducted with the aim to elucidate this understanding, by using a novel mold simulator equipped with a right-angle copper mold. The responding temperatures and heat fluxes across the mold hot-face and corner were firstly calculated through a 2D-inverse heat conduction program mathematical model, and the results suggested that the cooling ability and the fluctuation of heat fluxes around the mold corner are stronger than those for mold hot-face. With the help of power spectral density analysis and fast Fourier transformation, the four characteristic signals of heat fluxes were discussed in this paper. Next, the relation between the thickness of solidified shell and solidification time was fitted with the solidification square root law; as a result, the average solidification factor bar{K} for the hot-face shell is 2.32 mm/s1/2, and it is 2.77 mm/s1/2 for the shell near-corner. For the same oscillation marks (OMs), it appeared that the OMs positions on the shell corner are lower than those on the shell hot-face along the casting direction, because the stronger shrinkage of shell at the corner allows the overflowing steel to penetrate deeper into the larger gap between the shell corner and mold, which is demonstrated through the heat transfer analysis and metallographic examination. Finally, the interrelation between shell profile, mold oscillation, variation rate of heat flux, high-frequency heat flux and high-frequency temperature was discussed for above two cases, and the results suggested that meniscus conditions (heat transfer and melt flow) around the mold corner are more unsteady.

  8. Technological Practice of Processing Lead Anode Slime by Hydrometallurgy%铅阳极泥湿法处理工艺实践

    Institute of Scientific and Technical Information of China (English)

    黄宗耀

    2014-01-01

    铅阳极泥是提取金、银等贵金属的重要原料.控制电位在400~450 mV,使铜、锑和铋等贱金属优先于贵金属氧化浸出,贵金属得到富集.采用亚硫酸钠二次分银、甲醛还原银的工艺,得到品位98.86%的粗银,经银电解精炼,可得到99.99%的纯银.采用常温氯化分金、SO2还原得到粗金、粗金二次溶解以及草酸煮沸还原等工艺,得到纯金粉,金粉质量达到国标Au-1的标准.从铅阳极泥至金粉、粗银粉,金、银的直收率分别为95.65%和98.08%.整个工艺设计简短合理,技术指标较为理想.%Lead anode slime is an important raw material for extraction of gold,silver and other metals. Metals of copper,antimony and bismuth were oxidatively leached before precious metals by controlling potential in 400-450 mV and precious metals were enriched in residue.The 99.99% silver could be obtained by electrorefining crude silver of 98.86% , which was produced from lead anode slime using two steps of separating silver with sodium sulfite and reducing silver with formaldehyde. Crude gold was received by chloridizing separation of gold at room temperature and reduction with SO2 .Pure gold powder up to the standard of GB Au-1 was obtained by dissolving crude gold and reducing with oxalic acid at boiling temperature.With this process satisfactory results were obtained:the direct recovery rates of gold and silver from lead anode slime reached 95 .65% and 98 .08% respectively.

  9. INVESTIGATION OF THE INFLUENCE OF MOLD ROTATIONAL SPEED ON THE CAST WALL THICKNESS IN THE ROTATIONAL MOLDING PROCESS

    Directory of Open Access Journals (Sweden)

    Tomasz Jachowicz

    2013-09-01

    Full Text Available This paper presents the rotational molding process. The general principles of this polymer processing technology have been described. The main applications have been introduced and leading advantages and typical disadvantages of rotational molding process have been discussed. Based on the conducted experimental tests, the influence of changing one selected technological parameter, which characterized rotational molding process, on selected geometrical features of the polymer cast has been determined. Rotational mold’s speed around axes was changed and a thickness of cast walls has been measured. Laboratory test stand, processing properties of polymer, also test program and experimental test methodology have been described.

  10. Directed self-assembly of large scaffold-free multi-cellular honeycomb structures

    Energy Technology Data Exchange (ETDEWEB)

    Tejavibulya, Nalin; Youssef, Jacquelyn; Bao, Brian; Ferruccio, Toni-Marie; Morgan, Jeffrey R, E-mail: Jeffrey_Morgan@Brown.edu [Department of Molecular Pharmacology, Physiology and Biotechnology, Center for Biomedical Engineering, Brown University, G-B 393, Biomed Center, 171 Meeting St, Providence, RI 02912 (United States)

    2011-09-15

    A significant challenge to the field of biofabrication is the rapid construction of large three-dimensional (3D) living tissues and organs. Multi-cellular spheroids have been used as building blocks. In this paper, we create large multi-cellular honeycomb building blocks using directed self-assembly, whereby cell-to-cell adhesion, in the context of the shape and obstacles of a micro-mold, drives the formation of a 3D structure. Computer-aided design, rapid prototyping and replica molding were used to fabricate honeycomb-shaped micro-molds. Nonadhesive hydrogels cast from these micro-molds were equilibrated in the cell culture medium and seeded with two types of mammalian cells. The cells settled into the honeycomb recess were unable to attach to the nonadhesive hydrogel and so cell-to-cell adhesion drove the self-assembly of a large multi-cellular honeycomb within 24 h. Distinct morphological changes occurred to the honeycomb and its cells indicating the presence of significant cell-mediated tension. Unlike the spheroid, whose size is constrained by a critical diffusion distance needed to maintain cell viability, the overall size of the honeycomb is not limited. The rapid production of the honeycomb building unit, with its multiple rings of high-density cells and open lumen spaces, offers interesting new possibilities for biofabrication strategies.

  11. Flat Cellular (UMTS) Networks

    NARCIS (Netherlands)

    Bosch, H.G.P.; Samuel, L.G.; Mullender, S.J.; Polakos, P.; Rittenhouse, G.

    2007-01-01

    Traditionally, cellular systems have been built in a hierarchical manner: many specialized cellular access network elements that collectively form a hierarchical cellular system. When 2G and later 3G systems were designed there was a good reason to make system hierarchical: from a cost-perspective i

  12. A corneal mold to restore normal corneal dimensions.

    Science.gov (United States)

    Swinger, C A; Kornmehl, E W; York, S; Forman, J S

    1986-01-01

    A corneal mold is described that provides an MK corneal button of normal thickness and curvature from an edematous, post-mortem button. The uniform, processed tissue can then be used for experimental refractive surgery.

  13. Brief Guide to Mold, Moisture, and Your Home

    Science.gov (United States)

    Jump to main content US EPA United States Environmental Protection Agency Search Search Mold Share Facebook Twitter Google+ ... promptly and fix the water problem. It is important to dry water-damaged areas and items within ...

  14. Cork is used to make tooling patterns and molds

    Science.gov (United States)

    Hoffman, F. J.

    1965-01-01

    Sheet and waste cork are cemented together to provide a tooling pattern or mold. The cork form withstands moderately high temperatures under vacuum or pressure with minimum expansion, shrinkage, or distortion.

  15. Moldability Evaluation for Molded Parts Based on Fuzzy Reasoning

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Moldability evaluation for molded parts, which is the basis of concurrent design, is a key design stage in injection molding design. By moldability evaluation the design problems can be found timely and an optimum plastic part design achieved. In this paper, a systematic methodology for moldability evaluation based on fuzzy logic is proposed. Firstly, fuzzy set modeling for six key design attributes of molded parts is carried out respectively. Secondly, on the basis of this, the relationship between fuzzy sets for design attributes and fuzzy sets for moldability is established by fuzzy rules that are based on domain experts' experience and knowledge. At last the integral moldability for molded parts is obtained through fuzzy reasoning. The neural network based fuzzy reasoning approach presented in this paper can improve fuzzy reasoning efficiency greatly, especially for system having a large number of rules and complicated membership functions. An example for moldability evaluation is given to show the feasibility of this proposed methodology.

  16. Residual stresses in injection molded shape memory polymer parts

    Science.gov (United States)

    Katmer, Sukran; Esen, Huseyin; Karatas, Cetin

    2016-03-01

    Shape memory polymers (SMPs) are materials which have shape memory effect (SME). SME is a property which has the ability to change shape when induced by a stimulator such as temperature, moisture, pH, electric current, magnetic field, light, etc. A process, known as programming, is applied to SMP parts in order to alter them from their permanent shape to their temporary shape. In this study we investigated effects of injection molding and programming processes on residual stresses in molded thermoplastic polyurethane shape memory polymer, experimentally. The residual stresses were measured by layer removal method. The study shows that injection molding and programming process conditions have significantly influence on residual stresses in molded shape memory polyurethane parts.

  17. Mold Heating and Cooling Pump Package Operator Interface Controls Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Josh A. Salmond

    2009-08-07

    The modernization of the Mold Heating and Cooling Pump Package Operator Interface (MHC PP OI) consisted of upgrading the antiquated single board computer with a proprietary operating system to off-the-shelf hardware and off-the-shelf software with customizable software options. The pump package is the machine interface between a central heating and cooling system that pumps heat transfer fluid through an injection or compression mold base on a local plastic molding machine. The operator interface provides the intelligent means of controlling this pumping process. Strict temperature control of a mold allows the production of high quality parts with tight tolerances and low residual stresses. The products fabricated are used on multiple programs.

  18. Cavity air flow behavior during filling in microinjection molding

    DEFF Research Database (Denmark)

    Griffiths, C.A.; Dimov, S.S.; Scholz, S.

    2011-01-01

    Process monitoring of microinjection molding (μ-IM) is of crucial importance in understanding the effects of different parameter settings on the process, especially on its performance and consistency with regard to parts' quality. Quality factors related to mold cavity air evacuation can provide...... valuable information about the process dynamics and also about the filling of a cavity by a polymer melt. In this paper, a novel experimental setup is proposed to monitor maximum air flow and air flow work as an integral of the air flow over time by employing a microelectromechanical system gas sensor...... mounted inside the mold. The influence of four μIM parameters, melt temperature, mold temperature, injection speed, and resistance to air evacuation, on two air flow-related output parameters is investigated by carrying out a design of experiment study. The results provide empirical evidences about...

  19. Smart plastic functionalization by nanoimprint and injection molding

    DEFF Research Database (Denmark)

    Zalkovskij, Maksim; Thamdrup, Lasse Højlund; Smistrup, Kristian;

    2015-01-01

    In this paper, we present a route for making smart functionalized plastic parts by injection molding with sub-micrometer surface structures. The method is based on combining planar processes well known and established within silicon micro and sub-micro fabrication with proven high resolution...... the pattern. With this approach, we demonstrate the transfer of down to 140 nm wide holes on large areas with good structure fidelity on an injection molding steel insert. The durability of the sub-micrometer structures on the inserts have been investigated by running two production series of 102,000 and 73......,000 injection molded parts, respectively, on two different inserts and inspecting the inserts before and after the production series and the molded parts during the production series....

  20. Method and mold for casting thin metal objects

    Energy Technology Data Exchange (ETDEWEB)

    Pehrson, Brandon P; Moore, Alan F

    2014-04-29

    Provided herein are various embodiments of systems for casting thin metal plates and sheets. Typical embodiments include layers of mold cavities that are oriented vertically for casting the metal plates. In some embodiments, the mold cavities include a beveled edge such that the plates that are cast have a beveled edge. In some embodiments, the mold cavities are filled with a molten metal through an open horizontal edge of the cavity. In some embodiments, the mold cavities are filled through one or more vertical feed orifices. Further disclosed are methods for forming a thin cast metal plate or sheet where the thickness of the cast part is in a range from 0.005 inches to 0.2 inches, and the surface area of the cast part is in a range from 16 square inches to 144 square inches.

  1. Evaluation of Additive Manufacturing for Composite Part Molds

    Energy Technology Data Exchange (ETDEWEB)

    Duty, Chad E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Springfield, Robert M. [Tru Design, LLC, Knoxville, TN (United States)

    2015-02-01

    The ORNL Manufacturing Demonstration Facility (MDF) collaborated with Tru-Design to test the quality and durability of molds used for making fiber reinforced composites using additive manufacturing. The partners developed surface treatment techniques including epoxy coatings and machining to improve the quality of the surface finish. Test samples made using the printed and surface finished molds demonstrated life spans suitable for one-of-a-kind and low-volume applications, meeting the project objective.

  2. Ion channel recordings on an injection-molded polymer chip

    DEFF Research Database (Denmark)

    Tanzi, Simone; Matteucci, Marco; Christiansen, Thomas Lehrmann;

    2013-01-01

    In this paper, we demonstrate recordings of the ion channel activity across the cell membrane in a biological cell by employing the so-called patch clamping technique on an injection-molded polymer microfluidic device. The findings will allow direct recordings of ion channel activity to be made...... the injection-molded polymer device were in good agreement with data obtained from the commercial system....

  3. Bioprospection of yeasts as biocontrol agents against phytopathogenic molds

    Directory of Open Access Journals (Sweden)

    Márcia Maria Rosa-Magri

    2011-02-01

    Full Text Available Yeasts isolated from sugar cane and maize rhizosphere, leaves and stalks were screened against the phytopathogenic molds Colletotrichum sublineolum and Colletotrichum graminicola, both causal agents of the anthracnose disease in sorghum and maize, respectively. Strains identified as Torulaspora globosa and Candida intermedia were able to inhibit the mold growth, with the first species also exhibiting killer activity. No previous report on the application and potentiality of these yeasts as biocontrol agents were found neither the killer phenotype in Torulaspora globosa.

  4. Bioprospection of yeasts as biocontrol agents against phytopathogenic molds

    OpenAIRE

    Márcia Maria Rosa-Magri; Sâmia Maria Tauk-Tornisielo; Sandra Regina Ceccato-Antonini

    2011-01-01

    Yeasts isolated from sugar cane and maize rhizosphere, leaves and stalks were screened against the phytopathogenic molds Colletotrichum sublineolum and Colletotrichum graminicola, both causal agents of the anthracnose disease in sorghum and maize, respectively. Strains identified as Torulaspora globosa and Candida intermedia were able to inhibit the mold growth, with the first species also exhibiting killer activity. No previous report on the application and potentiality of these yeasts as bi...

  5. The Simulation and Optimization of Aspheric Plastic Lens Injection Molding

    Institute of Scientific and Technical Information of China (English)

    WEN Jialing; WEN Pengfei

    2005-01-01

    For the purpose of reducing the volumetric shrinkage and volumetric shrinkage variation, the process in injection molding of aspheric plastic lens was simulated, and several process parameters which include holding pressure, melt temperature, mold temperature, fill time, holding pressure time and cooling time were optimized by using an orthogonal experimental design method. Finally, the optimum process parameters and the influence degree of process parameters on the average volumetric shrinkage and the volumetric shrinkage variation are obtained.

  6. Material flow data for numerical simulation of powder injection molding

    Science.gov (United States)

    Duretek, I.; Holzer, C.

    2017-01-01

    The powder injection molding (PIM) process is a cost efficient and important net-shape manufacturing process that is not completely understood. For the application of simulation programs for the powder injection molding process, apart from suitable physical models, exact material data and in particular knowledge of the flow behavior are essential in order to get precise numerical results. The flow processes of highly filled polymers are complex. Occurring effects are very hard to separate, like shear flow with yield stress, wall slip, elastic effects, etc. Furthermore, the occurrence of phase separation due to the multi-phase composition of compounds is quite probable. In this work, the flow behavior of a 316L stainless steel feedstock for powder injection molding was investigated. Additionally, the influence of pre-shearing on the flow behavior of PIM-feedstocks under practical conditions was examined and evaluated by a special PIM injection molding machine rheometer. In order to have a better understanding of key factors of PIM during the injection step, 3D non-isothermal numerical simulations were conducted with a commercial injection molding simulation software using experimental feedstock properties. The simulation results were compared with the experimental results. The mold filling studies amply illustrate the effect of mold temperature on the filling behavior during the mold filling stage. Moreover, the rheological measurements showed that at low shear rates no zero shear viscosity was observed, but instead the viscosity further increased strongly. This flow behavior could be described with the Cross-WLF approach with Herschel-Bulkley extension very well.

  7. CAE for Injection Molding — Past, Present and the Future

    Science.gov (United States)

    Wang, Kuo K.

    2004-06-01

    It is well known that injection molding is the most effective process for mass-producing discrete plastic parts of complex shape to the highest precision at the lowest cost. However, due to the complex property of polymeric materials undergoing a transient non-isothermal process, it is equally well recognized that the quality of final products is often difficult to be assured. This is particularly true when a new mold or material is encountered. As a result, injection molding has often been viewed as an art than a science. During the past few decades, numerical simulation of injection molding process based on analytic models has become feasible for practical use as computers became faster and cheaper continually. A research effort was initiated at the Cornell Injection Molding Program (CIMP) in 1974 under a grant from the National Science Foundation. Over a quarter of the century, CIMP has established some scientific bases ranging from materials characterization, flow analysis, to prediction of part quality. Use of such CAE tools has become common place today in industry. Present effort has been primarily aimed at refinements of many aspects of the process. Computational efficiency and user-interface have been main thrusts by commercial software developers. Extension to 3-dimensional flow analysis for certain parts has drawn some attention. Research activities are continuing on molding of fiber-filled materials and reactive polymers. Expanded molding processes such as gas-assisted, co-injection, micro-molding and many others are continually being investigated. In the future, improvements in simulation accuracy and efficiency will continue. This will include in-depth studies on materials characterization. Intelligent on-line process control may draw more attention in order to achieve higher degree of automation. As Internet technology continues to evolve, Web-based CAE tools for design, production, remote process monitoring and control can come to path. The CAE

  8. Localized rapid heating process for precision chalcogenide glass molding

    Science.gov (United States)

    Li, Hui; He, Peng; Yu, Jianfeng; Lee, L. James; Yi, Allen Y.

    2015-10-01

    Precision glass molding is an important process for high volume optical fabrication. However, conventional glass molding is a bulk heating process that usually requires a long thermal cycle, where molding assembly and other mechanical parts are heated and cooled together. This often causes low efficiency and other heating and cooling related problems, such as large thermal expansion in both the molds and molded optics. To cope with this issue, we developed a localized rapid heating process to effectively heat only very small part of the glass. This localized rapid heating study utilized a fused silica wafer coated with a thin graphene layer to heat only the surface of the glass. The graphene coating functions as an electrical resistant heater when a power source was applied across the thin film coating, generating heat on and near the coating. The feasibility of this process was validated by both experiments and numerical simulation. To demonstrate the advantages of the localized rapid heating, both localized rapid heating process and bulk heating process were performed and carefully compared. The uniformity and quality of the molded sample by localized rapid heating process was also demonstrated. In summary, localized rapid heating process by using graphene coated fused silica wafer was characterized and can be readily implemented in replication of micro scale chalcogenide glasses. A fused silica wafer coated with a thin graphene layer was utilized for localized rapid heating only the surface of the glass. The graphene coating functions as an electrical resistant heater when a power source was applied across the thin film coating, generating high temperature on and near the coating. This process is fast and efficient since only interested areas are heated without affecting the entire glass substrate or the mold assembly. The uniformity and quality of the molded sample by localized rapid heating process was demonstrated by comparing both localized rapid heating

  9. Analysis of the volatiles in the headspace above the plasmodium and sporangia of the slime mould (Physarum polycephalum) by SPME-GCMS

    CERN Document Server

    Kateb, Huda al

    2013-01-01

    Solid phase micro-extraction (SPME) coupled with Gas Chromatography Mass Spectrometry (GC-MS) was used to extract and analyse the volatiles in the headspace above the plasmodial and sporulating stages of the slime mould Physarum Polycephalum. In total 115 compounds were identified from across a broad range of chemical classes. Although more (87) volatile organic compounds (VOCs) were identified when using a higher incubation temperature of 75oC, a large number of compounds (79) were still identified at the lower extraction temperature of 30oC and where the plasmodial stage was living. Far fewer compounds were extracted after sporulation at the two extraction temperatures. There were some marked differences between the VOCs identified in the plasmodial stage and after sporulation. In particular the nitrogen containing compounds acetonitrile, pyrrole, 2, 5-dimethyl-pyrazine and trimethyl pyrazine seemed to be associated with the sporulating stage. There were many compounds associated predominantly with the plas...

  10. Prediction of Mold Spoilage for Soy/Polyethylene Composite Fibers

    Directory of Open Access Journals (Sweden)

    Chinmay Naphade

    2015-01-01

    Full Text Available Mold spoilage was determined over 109 days on soy/PE fibers held under controlled temperatures (T ranging from 10°C to 40°C and water activities (aw from 0.11 to 0.98. Water activities were created in sealed containers using saturated salt solutions and placed in temperature-controlled incubators. Soy/PE fibers that were held at 0.823 aw or higher exhibited mold growth at all temperatures. As postulated, increased water activity (greater than 0.89 and temperature (higher than 25°C accelerated mold growth on soy/PE fibers. A slower mold growth was observed on soy/PE fibers that were held at 0.87 aw and 10°C. A Weibull model was employed to fit the observed logarithmic values of T, aw, and an interaction term log⁡T×log⁡aw and was chosen as the final model as it gave the best fit to the raw mold growth data. These growth models predict the expected mold-free storage period of soy/PE fibers when exposed to various environmental temperatures and humidities.

  11. Frequency of Mold Allergens in Allergic Rhinitis Patients

    Directory of Open Access Journals (Sweden)

    Bonyadi, MR. (PhD

    2014-06-01

    Full Text Available Background and Objective: Allergic rhinitis can be stimulated by several allergens. Molds are among these allergens and it is important to assess their frequency in different geographic area. Hence, we aimed at determining the frequency of mold allergens in allergic rhinitis patients referred to specialized clinics of Tabriz Imam Reza hospital, 2011. Material and Methods: This cross-sectional study was conducted on the serums of 90 rhinitis patients diagnosed by specialized physician. Using Immunoblotting method, the level of specific IgE against four molds including Penicillium, Aspergillus, Alternaria and Cladosporium were investigated. Results: Of 90 Patients, 40 were men (44.4% and 50 were women (55.6%. The participants were between 6 to 53 years and the most were 28-31years. The allergy was related to Penicillium (3.3%, Aspergillus (5.6%, Alternaria (13.3% and Cladosporium (4.4%. There was a significant statistical relation between age and allergic rhinitis to Alternaria (P=0.011. Conclusion: Molds can grow and proliferate in very humid environments. Because of low humidity climate in Tabriz (in the northwest of Iran, allergy to molds is relatively low in this region. Key words: Rhinitis Allergic; Mold; Allergy

  12. Precision glass molding of high-resolution diffractive optical elements

    Science.gov (United States)

    Prater, Karin; Dukwen, Julia; Scharf, Toralf; Herzig, Hans P.; Plöger, Sven; Hermerschmidt, Andreas

    2016-04-01

    The demand of high resolution diffractive optical elements (DOE) is growing. Smaller critical dimensions allow higher deflection angles and can fulfill more demanding requirements, which can only be met by using electron-beam lithography. Replication techniques are more economical, since the high cost of the master can be distributed among a larger number of replicas. The lack of a suitable mold material for precision glass molding has so far prevented an industrial use. Glassy Carbon (GC) offers a high mechanical strength and high thermal strength. No anti-adhesion coatings are required in molding processes. This is clearly an advantage for high resolution, high aspect ratio microstructures, where a coating with a thickness between 10 nm and 200 nm would cause a noticeable rounding of the features. Electron-beam lithography was used to fabricate GC molds with highest precision and feature sizes from 250 nm to 2 μm. The master stamps were used for precision glass molding of a low Tg glass L-BAL42 from OHARA. The profile of the replicated glass is compared to the mold with the help of SEM images. This allows discussion of the max. aspect-ratio and min. feature size. To characterize optical performances, beamsplitting elements are fabricated and their characteristics were investigated, which are in excellent agreement to theory.

  13. Development of mold for biodegradable materials

    Energy Technology Data Exchange (ETDEWEB)

    Japitana, F.H.; Jabrica, A.M. [Metals Industry Research and Develeopment Center, Manila (Philippines). Dept. of Science and Technology; Komatsu, M. [Komatsu Consulting Engineer Office, Iwaki City, Fukushima (Japan); Takeuchi, Y. [Osaka Univ., Osaka (Japan). Dept. of Mechanical Engineering

    2008-07-01

    The improper disposal of non-biodegradable plastics adversely affect global environmental factors, principles of sustainability, industrial ecology and ecoefficiency. Therefore, a new generation of bio-based polymeric products has been developed. These polylactides (PLA), cellulose esters, starch plastics and polyhydroxyalkanoates (PHAs) are made from renewable natural resources and are biodegradable. They meet environmental conditions and can compete with their petrochemical counterparts. Among them, PLA is particularly attractive as a sustainable alternative to synthetic polymers and a potential candidate for the fabrication of biocomposites. Certain blends have proved successful in medical implants, sutures and drug delivery systems because of their capacity to dissolve away with time. However, widespread use of PLA is limited because of cost. Biodegradable plastic products are currently 6 to 10 times more expensive than traditional plastics. Environmentalists argue that the cheaper price of traditional plastics does not reflect their true cost when their impact is considered. This paper presented a solution to reduce the production cost of biodegradable plastics. In particular, it described a newly developed plastic injection mold for biodegradable materials which can produce a scrapless product. The system reduces processing time because it is not necessary to remove any gating or runners after the injection process. Takeout robots ensure that the quality of the product is maintained. 12 figs.

  14. Determination of heat transfer coefficients at the polymer-mold-interface for injection molding simulation by means of calorimetry

    Science.gov (United States)

    Stricker, M.; Steinbichler, G.

    2014-05-01

    Appropriate modeling of heat transfer from the polymer material to the injection mold is essential to achieve accurate simulation results. The heat transfer is commonly modeled using convective heat transfer and applying heat transfer coefficients (HTC) to the polymer-mold-interface. The set HTC has an influence on the results for filling pressure, cooling performance and shrinkage, among others. The current paper, presents a new strategy to measure HTC in injection molding experiments using Newtons law of cooling. The heat flux is calculated out of demolding heat (measured by means of calorimetry), injection heat (measured by means of an IR-sensor), cooling time and part mass. Cavity surface area, average mold surface temperature and average part surface temperature lead to the HTC.

  15. Evolution of Surface Texture and Cracks During Injection Molding of Fiber-Reinforced, Additively-Manufactured, Injection Molding Inserts

    DEFF Research Database (Denmark)

    Hofstätter, Thomas; Mischkot, Michael; Pedersen, David Bue

    2016-01-01

    This paper investigates the lifetime and surfacedeterioration of additively-manufactured, injection-moulding inserts. The inserts were produced using digital light processing and were reinforcedwith oriented short carbon fibers. Theinserts were used during injection molding oflow-density polyethy......This paper investigates the lifetime and surfacedeterioration of additively-manufactured, injection-moulding inserts. The inserts were produced using digital light processing and were reinforcedwith oriented short carbon fibers. Theinserts were used during injection molding oflow......-density polyethylene until their failure. The molded products were used to analyse the development of the surface roughness and wear. By enhancing the lifetime of injection-molding inserts,this work contributes to the establishment of additively manufactured inserts in pilot production....

  16. Investigation of Heat Transfer at the Mold/Metal Interface in Permanent Mold Casting of Light Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Robert D. Pehlke; John T. Berry

    2005-12-16

    Accurate modeling of the metal casting process prior to creating a mold design demands reliable knowledge of the interfacial heat transfer coefficient at the mold metal interface as a function of both time and location. The phenomena concerned with the gap forming between the mold and the solidifying metal are complex but need to be understood before any modeling is attempted. The presence of mold coatings further complicates the situation. A commercial casting was chosen and studied in a gravity permanent mold casting process. The metal/mold interfacial heat transfer coefficient (IHTC) was the focus of the research. A simple, direct method has been used to evaluate the IHTC. Both the simulation and experiments have shown that a reasonably good estimate of the heat transfer coefficient could be made in the case studied. It has been found that there is a good agreement between experiments and simulations in the temperature profiles during the solidification process, given that the primary mechanism of heat transfer across the gap in permanent mold casting of light alloys is by conduction across the gap. The procedure utilized to determine the interfacial heat transfer coefficient can be applied to other casting processes. A recently completed project involving The University of Michigan and Mississippi State University, together with several industrial partners, which was supported by the USDOE through the Cast Metals Coalition, examined a number of cases of thermal contact. In an investigation which gave special consideration to the techniques of measurement, several mold coatings were employed and results presented as a function of time. Realistic conditions of coating thickness and type together with an appropriate combination of mold preheat and metal pouring temperature were strictly maintained throughout the investigation. Temperature sensors, in particular thermocouples, play an important part in validating the predictions of solidification models. Cooling

  17. 铅阳极泥中有价金属的分离研究%Research on Separation of Valued Metals from Lead Anode Slime

    Institute of Scientific and Technical Information of China (English)

    吴文花; 刘吉波; 王志坚; 苏正夫

    2013-01-01

    After natural stacking oxidation,lead anode slime was leached with potential controlled at 80 ℃ for four hours in medium of 5 mol/L sulfuric acid added with sodium chloride (c(Cl-) =3 mol/L) and oxidant of sodium chlorate with ratio of solid to liquid of 5 ∶ 1.The results show that the leaching rates of copper,bismuth,antimony and arsenic are all above 99%,the leaching rate of tellurium is above 97%,and the leaching rates of gold and silver are below 1% under the potential controlled leaching conditions including stacking duration of lead anode slime of over 4 days,oxidant dosage of >20%,and potential of 40~500 mV.Copper,bismuth,antimony,arsenic and tellurium are successfully separated from gold and silver.%铅阳极泥经过自然堆放氧化后,在5 mol/L硫酸介质中加入一定量的氯化钠(c(Cl-)=3 mol/L)和氧化剂氯酸钠,液固比为5∶1,80℃控制电位氧化浸出4h.结果表明,当铅阳极泥堆放氧化4天以上,氧化剂用量大于20%,电位400~500 mV时,铜、铋、锑、砷的浸出率均在99%以上,碲浸出率大于97%,金、银入液损失均小于1%,很好地实现了铜、铋、锑、砷、碲与金、银的分离.

  18. Plasma-nitriding assisted micro-texturing into stainless steel molds

    Directory of Open Access Journals (Sweden)

    Aizawa Tatsuhiko

    2015-01-01

    Full Text Available Micro-texturing has grown up to be one of the most promising procedures. This related application required for large-area, fine micro-texturing onto the stainless steel mold materials. A new method other than laser-machining, micro-milling or micro-EDM was awaited for further advancement of this micro-texturing. In the present paper, a plasma nitriding assisted micro-texturing was developed to make various kinds of micro-patterns onto the martensitic stainless steels. First, original patterns were printed onto the surface of substrate by using the ink-jet printer. Then, the masked substrate was subjected to high density plasma nitriding; the un-masked surfaces were nitrided to have higher hardness. This nitrided substrate was further treated by sand-blasting to selectively dig the soft, masked surfaces. Finally, the micro-patterned martensitic stainless steel substrate was fabricated as a mold to duplicate these micro-patterns onto the work materials. The spatial resolution and depth profile controllability of this plasma nitriding assisted micro-texturing was investigated for variety of initial micro-patterns. The original size and dimension of initial micro-patterns were precisely compared with the three dimensional geometry of micro-textures after blasting treatment. The plastic cover case for smart cellular phones was employed to demonstrate how useful this processing is in practice.

  19. Foaming morphology control of microcellular injection molded parts with gas counter pressure and dynamic mold temperature control

    Science.gov (United States)

    Shiu, Tai-Yi; Huang, Chao-Tsai; Chang, Rong-Yu; Hwang, Shyh-Shin

    2014-05-01

    Microcellular injection molding process is a promising solution for products with special requirements such as weight reduction, extra thin wall, high dimensional stability, clamping force reduction, etc. Despite microcellular foaming application used in reciprocating screw injection molding machine was built more than a decade, some limitations, such as poor surface quality or poor foaming control, confine the usage of this technology. Earlier CAE simulation tool for microcellular injection molding was not successful due to insufficient physical and computational considerations, limited by complicated bubble growth mechanism; so that, an economic and efficient tool for examining foaming quality of injection foaming product was lack. In this study, a recent developed three-dimensional simulation tool is used to predict injection foaming process. Predictions are carried out with commodity polypropylene and polystyrene with nitrogen and carbon dioxide supercritical fluids (SCFs). Comparisons of simulations between microcellular injection molding with and without counter pressure are discussed to provide insights into the correlation of surface quality and cell size distribution near the surface of product. Furthermore, comparisons between simulation predictions and experimental results of molding process, which is featured with dynamic mold temperature and gas counter pressure, are given for understanding quality improvement by controlling foaming morphology, and benefit of industrial application.

  20. Characteristics and infl uence factors of mold fi lling process in permanent mold with a slot gating system

    Directory of Open Access Journals (Sweden)

    Chen Changjun

    2009-11-01

    Full Text Available The main problems caused by improper gating are entrained aluminum oxide fi lms and entrapped gas. In this study, the slot gating system is employed to improve mold fi lling behavior and therefore, to improve the quality of aluminum castings produced in permanent molds. An equipment as well as operation procedures for real-time X-ray radiography of molten aluminum fl owing into permanent molds have been developed. Graphite molds transparent to X-rays are utilized which make it possible to observe the fl ow pattern through a number of vertically oriented gating systems. The investigation discovers that there are many infl uencing factors on the mold fi lling process. This paper focuses its research on some of the factors, such as the dimensions of the vertical riser and slot thickness, as well as roughness of the coating layer. The results indicate that molten metal can smoothly fi ll into casting cavity with a proper slot gating system. A bigger vertical riser, proper slot thickness and rougher coating can provide not only a better mold fi lling pattern, but also hot melt into the top of the cavity. A proper temperature gradient is obtainable, higher at the bottom and lower at the top of the casting cavity, which is in favor of feeding during casting solidifi cation.

  1. Effect of cross sectional geometry on PDMS micro peristaltic pump performance: comparison of SU-8 replica molding vs. micro injection molding.

    Science.gov (United States)

    Graf, Neil J; Bowser, Michael T

    2013-10-07

    Two different fabrication methods were employed to fabricate micropumps with different cross-sectional channel geometries. The first was to fabricate rectangular cross-sectional microchannel geometries using the well known fabrication method of replica molding (REM). The second, and far less utilized fabrication technique, was to create microchannel molds using an in-house fabricated handheld micro injection molding apparatus. The injection mold apparatus was designed for use with elastomeric room temperature vulcanization (RTV) polymers, as opposed to most other injection molding machines, which are designed for use with thermoplastic polymers. The injection mold's bottom plate was used as a microchannel molding template. The molding template was created by threading a small-diameter wire (150 μm or less) through the injection mold's bottom plate, with subsequent adhesion and smoothing of a thin piece of aluminum foil over the wire-raised injection mold template. When molded against, the template produced a rounded/Gaussian-shaped PDMS microchannel. The design of the injection mold will be presented, along with a direct comparison for micropump performance metrics such as flow rate, valving characteristics, and maximum backpressures attainable for each of the respective micropump channel geometries.

  2. Analysis of Injection Molding Process Based on MoldFlow/MPI for Large Plastic Pallet%基于MoldFlow/MPI的大型塑料托盘注射成型分析

    Institute of Scientific and Technical Information of China (English)

    段贤勇

    2012-01-01

    运用MoldFlow/MPI模块对大型塑料托盘注射成型过程进行模流分析,预测了可能出现的注射短射等缺陷,根据分析结果,提出了工艺优化方案,从而缩短模具设计制造周期。%Used MoldFlow/MPI to analyze the mold flow for the large plastic pallet molding process, and predict the possible injection molding defects such as injection molding short shot. According to the analysis, it gives process optimization to reduce the mold design and manufacture cycle.

  3. Residual stress distribution in injection molded parts

    Directory of Open Access Journals (Sweden)

    P. Postawa

    2006-08-01

    Full Text Available Purpose: The paper presents the results of the investigations of influence of the amorphous polystyrene (PSprocessing on the diversity of the internal stresses observed in the injection moulded piece.Design/methodology/approach: For the tests, the standardized mould piece designed for the investigations ofthe processing shrinkage of thermoplastics materials has been used. The samples have been prepared using theDesign of Experiment (DoE theory.The state of internal stresses has been analysed by means of photoelastic method (used stress viewer equipmenton the basis of the layout and size of the isochromatics (fields with the same colour, which determine the mouldpiece’s areas where the same value for the difference of main tensions. In the article the results of investigationsof influence of 5 chosen processing parameters such as injection temperature Tw, mould temperature Tf,clamping pressure pd, cooling time tch and the injection speed vw on the changes in isochromatics layout as adeterminant for diversity of internal stresses in injection moulded pieces have been presented.Findings: The performed investigations of the influence of injection conditions on the state of internal stressesreached for injection mould pieces were to determine the parameters of injection at which the achieved state ofthe stresses in the mould piece (described by the difference of main tensions will show the lowest values.Practical implications: Effects of examinations of influence of processing conditions on residual stress ininjection molded parts (presented in the article could find practical application in polymer industry, both smalland large enterprises.Originality/value: New approach to fast estimation of value of residual stresses were present in the paper.

  4. The thermal distortion of continuous-casting billet molds

    Science.gov (United States)

    Samarasekera, I. V.; Anderson, D. L.; Brimacombe, J. K.

    1982-03-01

    Preliminary mathematical analyses involving plate bending theory and two-dimensional elastic calculations have revealed that the dominant component contributing to the distortion of continuous-casting billet molds is thermal expansion in the transverse directions. A three-dimensional, elasto-plastic, finite-element analysis of the mold wall has then shown that localized yielding initiates in a region close to the meniscus. The plastic flow is a result of the high thermal stresses induced by the geometric restraint to bending coupled with the locally high temperatures. The resultant distortion profile of the mold down the centerline of a face exhibits a maximum outward bulge of 0.1 to 0.3 mm, which is bounded above by a region of negative taper (1˜2 pct/m) and below by a region of positive taper (˜0.4 pct/m). Measurements of mold wall movement in an operating billet caster using linear displacement transducers compare favorably with model predictions, except in the meniscus region. Case studies of several industrial billet molds have shown that lowering the meniscus level with respect to the location of constraints, or modifying the method of support of the mold tube within its housing so as to reduce the restraint to thermal expansion in the meniscus region, may minimize the extent of permanent distortion. Also, wall thickness can have a significant effect on thermal distortion. Increasing wall thickness results in an increase in both peak wall temperatures and thermal gradients. The former increases the local distortion while the latter causes higher thermal stress levels and possibly permanent distortion. Of the casting variables that can be manipulated to major advantage, cooling water flow rate is the most important. Increasing the water velocity reduces mold wall temperatures, as well as both the total and permanent distortion of the wall.

  5. Diagnosis parameters of mold filling pattern for optimization of a casting system

    Directory of Open Access Journals (Sweden)

    Jun-Ho Hong

    2012-11-01

    Full Text Available For optimal design of a gating system, the setting of diagnosis parameters is very important. In this study, the permanent mold casting process was selected because most of the other casting processes have more complicated factors that influence the mold filling pattern compared to the permanent mold casting process, such as the surface roughness of mold, gas generation from the mold wash and binder of sand mold, and the gas permeability through a sand mold, etc. Two diagnosis parameters (flow rate difference and arrival time difference of molten metal flow pattern in the numerical simulation are suggested for design of an optimum casting system with a permanent mold. The results show that the arrival time difference can be used as one important diagnosis parameter of the complexity of the runner system and its usefulness has been verified via making aluminum parts using permanent mold casting (Fig. 9.

  6. Improvement of machining quality of copper-plated roll mold by controlling temperature variation

    Institute of Scientific and Technical Information of China (English)

    Tae-Jin JE; Eun-Chae JEON; Sang-Cheon PARK; Doo-Sun CHOI; Kyung-Hyun WHANG; Myung-Chang KANG

    2011-01-01

    Micro prism film used in LCD industry can be manufactured by roll to roll method with copper-plated roll mold. As copper-plated roll mold is getting larger, pitch error is getting severer. The pitch error drops the quality of micro prism film. The main cause of the pitch error was investigated during machining large roll mold whose machined length was 1 200 mm. The temperature of machining system was elevated during machining roll mold, and this elevation induced thermal expansion of the system. The temperature variation around the roll mold also made thermal expansion of the roll mold. The amount of thermal expansion had strong relationship to the amount of pitch error. Therefore, the roll mold was machined after warming-up of machining system and precise temperature controller around copper-plated roll mold was installed, which minimized the temperature variation. Finally,precise micro prism patterns without pitch error were machined on the large roll mold.

  7. Orientation of Carbon Fibers in Copper matrix Produced by Powder Injection Molding

    Directory of Open Access Journals (Sweden)

    Irfan Shirazi M.

    2014-07-01

    Full Text Available Fiber orientation is a big challenge in short fiber reinforced composites. Powder injection molding (PIM process has some intrinsic fiber alignment associated with it. During PIM process fibers in skin region of moldings are aligned as these regions experience higher shear flow caused by the mold walls. Fibers in the core region remain randomly aligned as these regions are far from mold walls and experience lesser shear flow. In this study short carbon fiber (CF reinforced copper matrix composite was developed by PIM process. Two copper composite feedstock formulations were prepared having 5 vol% and 10 vol% CFs and a wax based binder system. Fiber orientation was controlled during injection molding by using a modified mold that has a diverging sprue. The sprue creates converging flow when feedstock enters into the mold cavity. Fiber orientation was analysed after molding using FESEM. The orientation of fibers can be controlled by controlling flow of feedstock into the mold.

  8. UG Mold Wizard in injection mold design application%UG MoldWizard在注射模具设计中的应用

    Institute of Scientific and Technical Information of China (English)

    陆龙福; 黄常翼

    2013-01-01

    Currently plastics increasingly broad application areas, plastic products has become the automotive, aerospace, electrical and electronics, packaging, building materials, agriculture and other fields indispensable parts and plastic parts are produced almost all through the plastic mold molding to obtain The. As technology advances and high-tech product development and continuous innovation, the technical plastics increasingly high demand, relying on manual mold design and manufacturing engineers is difficult to meet the needs of the development of production. UG mold soft-ware emergence and development, has become a contemporary mold design and manufacture of an important and indis-pensable auxiliary tools.%目前塑料制品的应用领域日益广阔,塑料产品已成为汽车、航空航天、电子电气、包装、建材、农业等领域中不可缺少的部分,而塑料制件的生产几乎都是通过塑料模具的成型来获得的。随着技术进步以及高科技产品的不断开发与创新,对塑料制品的各项技术要求越来越高,仅靠模具工程师手工设计与制造很难满足生产发展的需要。 UG模具软件的出现与发展,已成为当代模具设计与制造中不可缺少的重要辅助工具之一。

  9. Mold and mycotoxin problems encountered during malting and brewing.

    Science.gov (United States)

    Wolf-Hall, Charlene E

    2007-10-20

    Fusarium infections in grains can have severe effects on malt and beer. While some degree of Fusarium mycotoxins, such as deoxynivalenol, present in infected barley may be lost during steeping, the Fusarium mold is still capable of growth and mycotoxin production during steeping, germination and kilning. Therefore, detoxification of grain before malting may not be practical unless further growth of the mold is also prevented. Methods to reduce the amount of mold growth during malting are needed. Physical, chemical and biological methods are reviewed. Irradiation looks very promising as a means to prevent Fusarium growth during malting, but the effect on the surviving mold to produce mycotoxins and the effect on malt quality needs further study. Chemical treatments such as ozonation, which would not leave residual chemical in the beer also appear to be promising. Although biological control methods may be desirable, due to the use of "natural" inhibition, the effects of these inhibitors on malt and beer quality requires further investigation. It may also be possible to incorporate detoxifying genes into fermentation yeasts, which would result in detoxification of the wort when mold growth is no longer a problem. Development of these types of technological interventions should help improve the safety of products, such as beer, made from Fusarium infected grain.

  10. Relevant Aspects in Modeling of Micro-injection Molding

    Science.gov (United States)

    Nguyen-Chung, Tham; Jüttner, Gábor; Pham, Tung; Mennig, Günter

    2008-07-01

    Growing demands in the manufacturing of micro and precision components in plastics require new concepts for molding machines and micro molds on the one hand. On the other hand, a deeper understanding of the filling and solidification process in a micro mold is indispensable. In this work, the filling process of a micro spiral was analyzed by modeling the compressible flow using pressure dependent viscosity and adjusted heat transfer coefficients. At the same time, experimental filling studies were carried out on an accurately controlled micro-injection molding machine. Based on the relationship between the injection pressure and the filling degree, essential factors for the quality of the simulation can be identified. It can be shown that the flow behavior of the melt in a micro cavity of high aspect ratio is extremely dependent on the melt compressibility in the injection cylinder which needs to be considered in the simulation in order to predict an accurate flow rate. Moreover, the heat transfer coefficients between the melt and the mold wall vary significantly when changing cavity thickness and processing conditions. It is believed that a pressure dependent model for the heat transfer coefficient would be able to improve the quality of the process simulation.

  11. Measuring mechanical stresses on inserts during injection molding

    Directory of Open Access Journals (Sweden)

    Martina Heinle

    2015-05-01

    Full Text Available Assembly molding presents an interesting approach to innovative product solutions. Here, individual components can be simultaneously positioned, affixed, and provided with a casing. However, while overmolding elements in the mold cavity with hot polymer melt, high mechanical loads occur on, in some cases, very sensitive components such as electronic devices. For the design of such systems, it is important to know these stresses, the influences on their quantities, and mathematical options for their prediction. In this article, a new measurement method for determining the forces acting on a small element in the cavity during the injection molding process in three dimensions is presented. Therefore, a new installation method for a force sensor was developed. The results in this article concentrate on force changes during one molding cycle. Our research shows that there are different mechanical load spectra in the different phases of the molding process. For example, the force component in flow direction on an element in the cavity is positive in the direction of the flow during filling. However, after the filling step, the force becomes negative due to the contraction of the injected material and results in a continuously increasing permanent force.

  12. Computer Texture Mapping for Laser Texturing of Injection Mold

    Directory of Open Access Journals (Sweden)

    Yongquan Zhou

    2014-04-01

    Full Text Available Laser texturing is a relatively new multiprocess technique that has been used for machining 3D curved surfaces; it is more flexible and efficient to create decorative texture on 3D curved surfaces of injection molds so as to improve the surface quality and achieve cosmetic surface of molded plastic parts. In this paper, a novel method of laser texturing 3D curved surface based on 3-axis galvanometer scanning unit has been presented to prevent the texturing of injection mold surface from much distortion which is often caused by traditional texturing processes. The novel method has been based on the computer texture mapping technology which has been developed and presented. The developed texture mapping algorithm includes surface triangulation, notations, distortion measurement, control, and numerical method. An interface of computer texture mapping has been built to implement the algorithm of texture mapping approach to controlled distortion rate of 3D texture math model from 2D original texture applied to curvature surface. Through a case study of laser texturing of a high curvature surface of injection mold of a mice top case, it shows that the novel method of laser texturing meets the quality standard of laser texturing of injection mold.

  13. An investigation into the injection molding of PMR-15 polyimide

    Science.gov (United States)

    Colaluca, M. A.

    1984-01-01

    The chemorheological behavior of the PRM-15 molding compounds were characterized, the range of suitable processing parameters for injection molding in a reciprocating screw injection molding machine was determined, and the effects of the injection molding processing parameters on the mechanical properties of molded PMR-15 parts were studied. The apparatus and procedures for measuring viscosity and for determining the physical response of the material during heating are described. Results show that capillary rheometry can be effectively used with thermosets if the equipment is designed to overcome some of the inherent problems of these materials. A uniform temperature was provided in the barrel by using a circulating hot oil system. Standard capillary rheometry methods can provide the dependence of thermoset apparent viscosity on shear rate, temperature, and time. Process conditions resulting in complete imidization should be carefully defined. Specification of controlled oven temperature is inadequate and can result in incomplete imidization. For completely imidized PMR-15 heat at 15 C/min melt flow without gas evolution occurs in the temperature range of 325 C to 400 C.

  14. An in-mold packaging process for plastic fluidic devices.

    Science.gov (United States)

    Yoo, Y E; Lee, K H; Je, T J; Choi, D S; Kim, S K

    2011-01-01

    Micro or nanofluidic devices have many channel shapes to deliver chemical solutions, body fluids or any fluids. The channels in these devices should be covered to prevent the fluids from overflowing or leaking. A typical method to fabricate an enclosed channel is to bond or weld a cover plate to a channel plate. This solid-to-solid bonding process, however, takes a considerable amount of time for mass production. In this study, a new process for molding a cover layer that can enclose open micro or nanochannels without solid-to-solid bonding is proposed and its feasibility is estimated. First, based on the design of a model microchannel, a brass microchannel master core was machined and a plastic microchannel platform was injection-molded. Using this molded platform, a series of experiments was performed for four process or mold design parameters. Some feasible conditions were successfully found to enclosed channels without filling the microchannels for the injection molding of a cover layer over the plastic microchannel platform. In addition, the bond strength and seal performance were estimated in a comparison with those done by conventional bonding or welding processes.

  15. Microwaves energy in curing process of water glass molding sands

    Directory of Open Access Journals (Sweden)

    Granat K.

    2007-01-01

    Full Text Available This work presents the results of investigation of microwave heating on hardening process of water glass molding sands. Essential influence of this heating process on basic properties such as: compression, bending and tensile strength as well as permeability and abrasion resistance has been found. It has been proved, that all investigated sorts of sodium water glass with a module between 2.0 and 3.3 can be used as a binder of molding sands in microwave curing process. It has been found during analysis of research results of sands with 2.5 % water glass addition that they are practically the same as in case of identical molding sands dried for 120 minutes at the temperature of 110°C, used for comparative purposes. Application of microwave curing of molding sands with water glass, however, guarantees reduction of hardening time (from 120 to 4 minutes as well as significant reduction of energy consumption. Attempts of two stage hardening of the investigated water glass molding sands have also been carried out, that is after an initial hardening during a classical CO2 process (identical sands have also been tested for comparison after CO2 blowing process and additional microwave heating. It has been found that application of this kind of treatment for curing sands with 2.5 % sodium water glass content and module from 2.0 up to 3.3 results in the improvement of properties in comparison to classical CO2 process.

  16. Surface Graphite Degeneration in Ductile Iron Castings for Resin Molds

    Institute of Scientific and Technical Information of China (English)

    Iulian Riposan; Mihai Chisamera; Stelian Stan; Torbjorn Skaland

    2008-01-01

    The objective of this paper is to review the factors influencing the formation of degenerated graph-ite layers on the surfaces of ductile iron castings for chemical rosins-acid molding and coro-making systems and how to reduce this defect. In the rosin mold technique the sulphur in the P-toluol sulphonic acid (PTSA),usually used as the hardener, has been identified as one factor causing graphite degeneration at the metal-mold interface. Less than 0.15% S in the mold (or even less than 0.07% S) can reduce the surface layer depth. Oxygen may also have an effect, especially for sulphur containing systems with turbulent flows in the mold, water-bearing no-bake binder systems, Mg-Silica reactions, or dross formation conditions. Despite the lower level of nitrogen in the iron melt after magnesium treatment (less than 90 ppm), nitrogen bearing res-ins have a profound effect on the frequency and severity of surface pinholes, but a limited influence on sur-face graphite degeneration.

  17. Development of the computer-aided process planning (CAPP system for polymer injection molds manufacturing

    Directory of Open Access Journals (Sweden)

    J. Tepić

    2011-10-01

    Full Text Available Beginning of production and selling of polymer products largely depends on mold manufacturing. The costs of mold manufacturing have significant share in the final price of a product. The best way to improve and rationalize polymer injection molds production process is by doing mold design automation and manufacturing process planning automation. This paper reviews development of a dedicated process planning system for manufacturing of the mold for injection molding, which integrates computer-aided design (CAD, computer-aided process planning (CAPP and computer-aided manufacturing (CAM technologies.

  18. Discussion on compact mechanism of air-stream and synchro-formed clamp plate impact molding

    Directory of Open Access Journals (Sweden)

    Zhenling WANG

    2004-11-01

    Full Text Available Applying the air impact molding method to mold the complicated pattern with wider opening surface and deeper concave, there always exist vaulted phenomenon and lower compactibility of sand mold over the entrance and the concave regions. Using the air-stream and synchro-formed clamp plate impact molding, however, this problem will be preferably solved. In this paper, the compact mechanism of the new molding method and the effect of some configuration factors, such as the area flowed by compressed air and the highness of the protruding block displacement around the diffluent clamp plate, on the compactibility of sand mold were discussed.

  19. Reversible quantum cellular automata

    CERN Document Server

    Schumacher, B

    2004-01-01

    We define quantum cellular automata as infinite quantum lattice systems with discrete time dynamics, such that the time step commutes with lattice translations and has strictly finite propagation speed. In contrast to earlier definitions this allows us to give an explicit characterization of all local rules generating such automata. The same local rules also generate the global time step for automata with periodic boundary conditions. Our main structure theorem asserts that any quantum cellular automaton is structurally reversible, i.e., that it can be obtained by applying two blockwise unitary operations in a generalized Margolus partitioning scheme. This implies that, in contrast to the classical case, the inverse of a nearest neighbor quantum cellular automaton is again a nearest neighbor automaton. We present several construction methods for quantum cellular automata, based on unitaries commuting with their translates, on the quantization of (arbitrary) reversible classical cellular automata, on quantum c...

  20. Application of Vacuum Drying to Silica Sol Ceramic Mold

    Institute of Scientific and Technical Information of China (English)

    Ming ZENG; Xinqiang YUAN; Baoluo SHEN; Yunqiu ZHENG

    2008-01-01

    Silica sol ceramic mold was made at room temperature with JN-30 silica sol, silica powder and NH4Cl. It is found that the harden time of silica sol ceramic mold is only 0.5 to 1.5 h under the amount of NH4CI solution of 7% to 8% with 15% concentration, and less surface cracks occur by using vacuum drying. The proper vacuum drying process parameters: vacuum drying temperature is 80 to 100℃, drying time is 5 h and vacuum is 0.06 to 0.07 MPa. The harden mechanics, vacuum drying mechanics and the reason of less surface cracks of silica sol ceramic mold by vacuum drying were also analyzed in this paper.

  1. Treatment principles for the management of mold infections.

    Science.gov (United States)

    Kontoyiannis, Dimitrios P; Lewis, Russell E

    2014-11-06

    Survival rates among immunocompromised patients with invasive mold infections have markedly improved over the last decade with earlier diagnosis and new antifungal treatment options. Yet, increasing antifungal resistance, breakthrough infections with intrinsically resistant fungi, and potentially life-threatening adverse effects and drug interactions are becoming more problematic, especially with prolonged therapy. Evidence-based recommendations for treating invasive aspergillosis and mucormycosis provide excellent guidance on the initial workup and treatment of these molds, but they cannot address all of the key management issues. Herein, we discuss 10 general treatment principles in the management of invasive mold disease in immunocompromised patients and discuss how these principles can be integrated to develop an effective, individualized treatment plan.

  2. Injection Molding and its application to drug delivery.

    Science.gov (United States)

    Zema, Lucia; Loreti, Giulia; Melocchi, Alice; Maroni, Alessandra; Gazzaniga, Andrea

    2012-05-10

    Injection Molding (IM) consists in the injection, under high pressure conditions, of heat-induced softened materials into a mold cavity where they are shaped. The advantages the technique may offer in the development of drug products concern both production costs (no need for water or other solvents, continuous manufacturing, scalability, patentability) and technological/biopharmaceutical characteristics of the molded items (versatility of the design and composition, possibility of obtaining solid molecular dispersions/solutions of the active ingredient). In this article, process steps and formulation aspects relevant to IM are discussed, with emphasis on the issues and advantages connected with the transfer of this technique from the plastics industry to the production of conventional and controlled-release dosage forms. Moreover, its pharmaceutical applications thus far proposed in the primary literature, intended as either alternative manufacturing strategies for existing products or innovative systems with improved design and performance characteristics, are critically reviewed.

  3. Influence of melt mixer on injection molding of thermoset elastomers

    Science.gov (United States)

    Rochman, Arif; Zahra, Keith

    2016-10-01

    One of the drawbacks in injection molding is that the plasticizing screw is short such that polymers having high concentrations of additives, such as thermoset elastomers, might not mix homogeneously within the short period of time during the plasticizing stage. In this study, various melt mixers inside the nozzle chamber, together forming a mixing nozzle, were developed. Three different materials were investigated, namely nitrile butadiene rubber (NBR), ethylene propylene-diene monomer (EPDM) and fluorocarbon (FKM). The use of these melt mixers resulted in better homogeneity and properties of the molded parts despite a curing time reduction of 10 s. This was due to the increase in mixing and shearing introduced a higher rate of crosslinking formation in the molded parts.

  4. Modeling of Mold Filling and Solidification in Lost Foam Casting

    Institute of Scientific and Technical Information of China (English)

    Fengjun LI; Houfa SHEN; Baicheng LIU

    2003-01-01

    Based on the characteristics of the lost foam casting (LFC) and the artificial neural network technique, a mathematicalmodel for the simulation of the melt-pattern interface movement during the mold filling of LFC has been proposed andexperimentally verified. The simulation results are consistent with the experiments in both the shapes of melt frontand filling sequences. According to the calculated interface locations, the fluid flow and the temperature distributionsduring the mold filling and solidification processes were calculated, and the shrinkage defect of a lost foam ductileiron casting was predicted by considering the mold wall movement in LFC. The simulation method was applied tooptimize the casting design of lost foam ductile iron castings. It is shown that the model can be used for the defectsprediction and for casting design optimization in the practical LFC production.

  5. Long fiber polymer composite property calculation in injection molding simulation

    Science.gov (United States)

    Jin, Xiaoshi; Wang, Jin; Han, Sejin

    2013-05-01

    Long fiber filled polymer composite materials have attracted a great attention and usage in recent years. However, the injection and compression molded long fiber composite materials possess complex microstructures that include spatial variations in fiber orientation and length. This paper presents the recent implemented anisotropic rotary diffusion - reduced strain closure (ARD-RSC) model for predicting fiber orientation distribution[1] and a newly developed fiber breakage model[2] for predicting fiber length distribution in injection and compression molding simulation, and Eshelby-Mori-Tanaka model[3,4] with fiber-matrix de-bonding model[5] have been implemented to calculate the long fiber composite property distribution with predicted fiber orientation and fiber length distributions. A validation study on fiber orientation, fiber breakage and mechanical property distributions are given with injection molding process simulation.

  6. Permanent Mold Casting of JIS-AC4C Aluminum Alloy Using a Low-Temperature Mold

    Science.gov (United States)

    Yamagata, Hiroshi; Nikawa, Makoto

    2011-01-01

    Permanent mold casting using mold temperatures below 200° C was conducted to obtain a high-strength, thin-walled casting. Al-7.36 mass% Si -0.18 Cu- 0.27Mg-0.34Fe alloy JIS-AC4C was cast using a bottom pouring cast plan. The product had a rectangular tube shape (70 mm W x 68 mm D x 180 mm H) with wall thicknesses of 1, 3 and 5 mm. The effect of heat insulation at the melt path was compared when using a sand runner insert and when using a steel runner insert as well as a powder mold release agent. Fine microstructures were observed in the casting. The smaller the thickness, the higher the hardness with smaller secondary dendrite arm spacing (SDAS). However, the hardness and the SDAS were unaffected by the mold temperature. It was proposed that the avoidance of the formation of primary α dendrite at the melt path generates a higher strength casting with adequate mold filling.

  7. Use of the smart tongue to monitor mold growth and discriminate between four mold species grown in liquid media

    Energy Technology Data Exchange (ETDEWEB)

    Zhao Guangying, E-mail: zhaogy-user@163.com [Food Safety Key Lab of Zhejiang Province, Department of Food Quality and Safety, Zhejiang Gongshang University, Hangzhou 310035 (China); Lin Xiaona; Dou Wenchao; Tian Shiyi; Deng Shaoping; Shi Jinqin [Food Safety Key Lab of Zhejiang Province, Department of Food Quality and Safety, Zhejiang Gongshang University, Hangzhou 310035 (China)

    2011-04-01

    A novel voltammetric electronic tongue, smart tongue, was employed to monitor the growth of mold and to differentiate between four types of mold grown in liquid medium. Principal component analysis (PCA) was used to extract the relevant information obtained by the smart tongue. Reference growth curves were based on measurements of dry weight and pH. The growth detected by the smart tongue was basically consistent with that observed by the measurement of dry weight and pH. The optimal combinations of electrodes and frequencies for monitoring growth were as follows: for Aspergillus, both the Pt and Au electrodes at 1 Hz, 10 Hz and 100 Hz; for Penicillium, the Pt and W electrodes at 100 Hz; for Mucor, the Pt, Pd and W electrodes at the three frequency segments; for Rhizopus, the Pd, Ti and Ag electrodes at the three frequency segments. The Ag electrode at 10 Hz or 100 Hz frequency could differentiate well between the four types of mold for culturing 6 h in the liquid media. Therefore, the smart tongue has a promising future as a modern rapid analytical technology for the real time detection of the growth of mold and for the classification model of mold.

  8. 240 Mold Sensitization in Chronic Rhinosinusitis Patients

    Science.gov (United States)

    Gawlik, Radoslaw; Czecior, Eugeniusz

    2012-01-01

    Background It is estimated that about 10% of the population have IgE antibodies to common inhalant molds. Exposure to fungal allergens could be linked to the presence and persistence of asthma, rhinitis and atopic dermatitis. Mold sensitization is a risk factor for development and deterioration of upper airway allergy, especially chronic rhinosinusitis. We addressed the incidence of mold allergy measured as specific IgE to molds and skin prick tests in chronic sinusitis patients. We assessed prevalence of allergic reactions to mould among surgery treated chronic sinusitis patients. Methods A group of 28 chronic sinusitis patients after surgery were included into the study. Routine medical examination, skin prick tests with common inhaled allergens and extended mold panel (Alternaria alternate, Cladosporium herbarium, Aspergilus fumigatus, Candida albicans, Mucor mucedo, Botrytis cinerea, Rhisopus nigricans, Penicilliumi notatum, Fusarum moniliforme Pullularia pullulans (Allergopharma, Germany), tIgE, asIgE measurement were performed (Phadia, Sweden). All investigated patients were consulted by laryngologist and mycological examination was performed. Results We found that sensitization to at least one allergen was present in 43.8(14/32) of sinusitis patients. The most prevalent was sensitization to house dust mite Dermatophagoides pt., found in 21.8 % (7/32) patients. Positive results of skin prick tests with Candida albicans we observed in 18.8% (6/32), with Alternaria alternate in 15,6% (5/32), Cladosporium herbarium in 6,3% (2/32), Aspergilus fumigatus in 3,13 % (1/32). None of investigated patients presented sensitization to other mold allergens. Microbiological methods demonstrated fungal infection only in 2 patients. Conclusions Almost half of chronic sinusitis patients presented sensitization to at least one allergen. Fungal allergy is relatively rare in chronic sinusitis patients.

  9. 煤泥分选超净煤的药剂研究∗%Research on reagent for coal slime separation of ultra-clean coal

    Institute of Scientific and Technical Information of China (English)

    王婕; 付晓恒; 李珞铭; 杨磊; 潘悦怡; 舒元峰

    2016-01-01

    选取动力煤选煤厂煤泥为研究对象,利用傅里叶红外光谱(FTIR)仪和接触角测量仪对比了超细粉碎后的煤泥以及和乳化柴油作用后的煤泥的官能团和润湿性的变化,分析了在絮团浮选中乳化柴油的作用机理.在此基础上,研究了乳化柴油的种类和用量以及分散剂或起泡剂的添加对煤泥絮团分选超净煤的影响.试验结果表明,乳化柴油中的非离子型表面活性剂极性基与煤表面的含氧官能团发生氢键吸附,使煤表面含氧官能团含量减少,接触角增大,疏水性增强;1#乳化柴油的浮选效果优于2#乳化柴油;1#乳化药剂的最佳药剂用量为57.96 kg/t;在分选过程中添加分散剂后得到的超净煤灰分减小,产率也减小;添加起泡剂后分选效果优于单独使用乳化柴油的分选效果.%The authors took coal slime of steam coal preparation plant as object of study, used FTIR and contact angle goniometer to compare the changes of functional groups and wetta-bility of coal slime with or without adding the emulsified diesel oil after ultrafine grinding,ana-lyzed functional mechanism of emulsified diesel during flocculation flotation,and based upon the experiment,studied the influences of types,dosages of emulsified diesel and addition of disper-sant or frother on coal slime flocculation separating ultra-clean coal. The results showed that the hydrogen bonding adsorption occurred between the nonionic surfactant polar groups in emulsified diesel oil and the oxygen-containing functional groups on surface of coal,which leaded reducing on content of oxygen containing functional groups on the surface of coal and increasing of the con-tact angle and wettability,therefore,the flotation results of 1 # emulsified diesel was better than the 2 # emulsified diesel,the optimum dosage of 1 # emulsified diesel was 57.96 kg/t,the ash of the ultra-clean coal with dispersants reduced during separation and

  10. 鸡西地区采用煤泥烘干技术加工电力燃料的可行性分析%Feasibility Study of Processing Power Fuel With the Slime Oven Drying Technology in Jixi District

    Institute of Scientific and Technical Information of China (English)

    毕明涛

    2011-01-01

    煤炭洗选和火力发电是鸡西煤电基地建设中的两个重要产业项目。当前,在电力燃料紧俏的情况下,如果将滞销的煤炭洗选副产品"煤泥"加工成可用的电力燃料对两个产业均有利。阐述了开发煤泥用作电力燃料的可行性,提出了煤泥烘干技术的工艺方案并做了经济效益分析。%Coal washing and thermal power generation are two key industries in Jixi.Considering the shortage of the electric power fuel,the coal slime which is the by-product of coal washing can be turned into the electrical fuel which is benefit for the development of power generation and electrical fuel production.This paper study the feasibility to develop slime as power fuel and put forward a coal slime drying technological scheme.

  11. Biological Control of Olive Green Mold in Agaricus bisporus Cultivation.

    Science.gov (United States)

    Tautorus, T E; Townsley, P M

    1983-02-01

    Successful methods to control the damaging weed mold Chaetomium olivaceum (olive green mold) in mushroom beds are not presently known. An attempt was made to control C. olivaceum by biological means. A thermophilic Bacillus sp. which showed dramatic activity against C. olivaceum on Trypticase soy agar (BBL Microbiology Systems)-0.4% yeast extract agar plates was isolated from commercial mushroom compost (phase I). When inoculated into conventional and hydroponic mushroom beds, the bacillus not only provided a significant degree of protection from C. olivaceum, but also increased yields of Agaricus bisporus.

  12. FIBER ORIENTATION IN INJECTION MOLDED LONG CARBON FIBER THERMOPLASTIC COMPOSITES

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jin; Nguyen, Ba Nghiep; Mathur, Raj N.; Sharma, Bhisham; Sangid, Michael D.; Costa, Franco; Jin, Xiaoshi; Tucker III, Charles L.; Fifield, Leonard S.

    2015-03-23

    A set of edge-gated and center-gated plaques were injection molded with long carbon fiber-reinforced thermoplastic composites, and the fiber orientation was measured at different locations of the plaques. Autodesk Simulation Moldflow Insight (ASMI) software was used to simulate the injection molding of these plaques and to predict the fiber orientation, using the anisotropic rotary diffusion and the reduced strain closure models. The phenomenological parameters of the orientation models were carefully identified by fitting to the measured orientation data. The fiber orientation predictions show very good agreement with the experimental data.

  13. Study on Antigravity Mold Filling by Conservative Scalar Method

    Institute of Scientific and Technical Information of China (English)

    李日; 王友序; 杨根仓; 毛协民

    2003-01-01

    By SIMPLE method and Van-Leer scheme, a program on numerical simulation for 3D mold filling has been developed. The fluid flow field of gas and liquid is calculated in couples by a single phase N-S equation using SIMPLE method, and free surface control equation is handied by Van-Leer scheme. Then it is verified by an anti-gravity mold filling of thin wall plate. In order to demonstrate its ability to simulate 3D casting, an anti-gravity mould filling of a cube is computed by the program.

  14. Polymer microlens array integrated with imaging sensors by UV-molding technique

    Science.gov (United States)

    Lai, Jianjun; Zhao, Yue; Ke, Caijun; Yi, Xinjian; Zhang, TianXu

    2005-01-01

    Fabrication of Polymer microlens array based on UV-molding techniques is presented. UV-molding enables for the integration of polymer microlens array on top of arbitrary substrates like glass, silicon other polymeric films. In this technique, photoresist or glass mold is first fabricated by conventional photolithnic method and subsequently served as transparent replication tool. UV curable polymer resin is then coated on patterned or unpatterned substrates and a contact mask aligner is used to align substrates and replication mold tool and then make the mold immersed into the resin. Replication of polymer on substrates is achieved by UV photopolymerisation of the resin. Resin thickness and gap distance between mold and substrate are carefully controlled in order to obtain acceptable thickness of cured polymer base. The UV molding technique was used to molding of a polymer film carring microlens array on the surface of an experimental CCD imaging sensor chip in this paper to enhance its fill factor and sensitivity.

  15. Evaluation of the mold-filling ability of alloy melt in squeeze casting

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The mold-filling ability of alloy melt in squeeze casting process was evaluated by means of the maximum length of Archimedes spiral line. A theoretical evaluating model to predict the maximum filling length was built based on the flowing theory of the incompressible viscous fluid. It was proved by experiments and calculations that the mold-filling pressure and velocity are prominent influencing factors on the mold-filling ability of alloy melt. The mold-filling ability increases with the increase of the mold-filling pressure and the decrease of the proper mold-filling velocity. Moreover, the pouring temperature relatively has less effect on the mold-filling ability under the experimental conditions. The maximum deviation of theoretical calculating values with experimental results is less than 15%. The model can quantitatively estimate the effect of every factor on the mold-filling ability.

  16. Finite element stress analysis of a compression mold. Final report. [Using SASL and WILSON codes

    Energy Technology Data Exchange (ETDEWEB)

    Watterson, C.E.

    1980-03-01

    Thermally induced stresses occurring in a compression mold during production molding were evaluated using finite element analysis. A complementary experimental stress analysis, including strain gages and thermocouple arrays, verified the finite element model under typical loading conditions.

  17. Application of statistical methods for analyzing the relationship between casting distortion, mold filling, and interfacial heat transfer in sand molds

    Energy Technology Data Exchange (ETDEWEB)

    Y. A. Owusu

    1999-03-31

    This report presents a statistical method of evaluating geometric tolerances of casting products using point cloud data generated by coordinate measuring machine (CMM) process. The focus of this report is to present a statistical-based approach to evaluate the differences in dimensional and form variations or tolerances of casting products as affected by casting gating system, molding material, casting thickness, and casting orientation at the mold-metal interface. Form parameters such as flatness, parallelism, and other geometric profiles such as angularity, casting length, and height of casting products were obtained and analyzed from CMM point cloud data. In order to relate the dimensional and form errors to the factors under consideration such as flatness and parallelism, a factorial analysis of variance and statistical test means methods were performed to identify the factors that contributed to the casting distortion at the mold-metal interface.

  18. Heterogeneous cellular networks

    CERN Document Server

    Hu, Rose Qingyang

    2013-01-01

    A timely publication providing coverage of radio resource management, mobility management and standardization in heterogeneous cellular networks The topic of heterogeneous cellular networks has gained momentum in industry and the research community, attracting the attention of standardization bodies such as 3GPP LTE and IEEE 802.16j, whose objectives are looking into increasing the capacity and coverage of the cellular networks. This book focuses on recent progresses,  covering the related topics including scenarios of heterogeneous network deployment, interference management i

  19. The effect of mold materials on the overlay accuracy of a roll-to-roll imprinting system using UV LED illumination within a transparent mold

    Science.gov (United States)

    Choi, Sungwoo; Kook, YunHo; Kim, ChulHo; Yoo, SoonSung; Park, Kwon-Shik; Kim, Seok-min; Kang, Shinill

    2016-06-01

    Although several studies on the roll-to-roll (R2R) imprinting process have reported achieving flexible electronics, improving the alignment accuracy in the overlay process of R2R imprinting is recognized as the biggest problem for the commercialization of this technology. For an overlay technique with high alignment accuracy, it is essential to develop a roll mold with high positional accuracy. In this study, a method for fabricating a roll mold with high positional accuracy is proposed by wrapping a thin glass substrate flexible mold around the transparent roll base, because it can provide higher mechanical strength and thermal stability than a conventional polymer substrate. To confirm the usability of the proposed process, the prepared roll mold was used to fabricate a test pattern of thin-film transistor backplane for a rollable display. The positional and overlay accuracy of the roll mold with the proposed thin glass substrate flexible mold were compared with the roll mold with a conventional polymer substrate flexible mold. Large-area transparent flexible molds with a size of 470  ×  370 mm were fabricated by an ultraviolet (UV) imprinting process on thin glass and polyethylene terephthalate substrates, and these flexible molds were wrapped around a roll base of 125 mm radius through a precision alignment process. After an anti-adhesion treatment and the wrapping process, the roll mold with the polymer substrate showed a ~180 μm positional error, whereas the thin glass substrate showed a ~30 μm positional error. After the overlay process using the R2R imprinting system with the alignment system, an average overlay error of ~3 μm was obtained when the thin glass flexible wrapped roll mold was used, whereas a ~22 μm overlay error was obtained when the polymer substrate flexible wrapped roll mold was used.

  20. Injection molding of iPP samples in controlled conditions and resulting morphology

    Energy Technology Data Exchange (ETDEWEB)

    Sessa, Nino, E-mail: ninosessa.ns@gmail.com; De Santis, Felice, E-mail: fedesantis@unisa.it; Pantani, Roberto, E-mail: rpantani@unisa.it [Department of Industrial Engineering, University of Salerno, 84084 Fisciano (Italy)

    2015-12-17

    Injection molded parts are driven down in size and weight especially for electronic applications. In this work, an investigation was carried out on the process of injection molding of thin iPP samples and on the morphology of these parts. Melt flow in the mold cavity was analyzed and described with a mathematical model. Influence of mold temperature and injection pressure was analyzed. Samples orientation was studied using optical microscopy.

  1. Theoretical Analysis of the Solidification of Aluminum Alloy Billet in Air-Slip DC Mold

    Institute of Scientific and Technical Information of China (English)

    于赟; 马乃恒; 许振明; 李建国

    2004-01-01

    Based on the heat transfer analysis of Air-Slip DC mold, a numerical model was presented to study the quantitative relationships between critical solidification layer and casting rate, pouring temperature and mold cooling ability etc. The analytical results show that the Air-Slip mold heat transfer condition plays important roles on choices of a casting rate and the pouring temperature, and that the product of billet diameter and casting rate is a certain constant under a certain condition of the mold.

  2. Mold Species in Dust from the International Space Station Identified and Quantified by Mold Specific Quantitative PCR

    Science.gov (United States)

    Vesper, Stephen J.; Wong, Wing; Kuo, C. Mike; Pierson, Duane L.

    2008-01-01

    Dust was collected over a period of several weeks in 2007 from various HEPA filters in the U.S. Laboratory Module of the International Space Station (ISS). The dust was returned on the Space Shuttle Atlantis, mixed, sieved, and the DNA was extracted. Using a DNA-based method called mold specific quantitative PCR (MSQPCR), 39 molds were measured in the dust. Opportunistic pathogens Aspergillus flavus and A. niger and toxin producers Penicillium chrysogenum and P. brevicompactum were found at relatively high concentrations (compared to U.S. homes). No cells of the opportunistic pathogens A. fumigatus, A. terreus, Fusarium solani or Candida albicans were detected.

  3. Quantifying mold biomass on gypsum board: Comparison of ergosterol and beta-N-acetylhexosaminidase as mold biomass parameters

    DEFF Research Database (Denmark)

    Reeslev, M.; Miller, M.; Nielsen, Kristian Fog

    2003-01-01

    Two mold species, Stachybotrys chartarum and Aspergillus versicolor, were inoculated onto agar overlaid with cellophane, allowing determination of a direct measurement of biomass density by weighing. Biomass density, ergosterol content, and beta-N-acetylhexosaminidase (3.2.1.52) activity were...... monitored from inoculation to stationary phase. Regression analysis showed a good linear correlation to biomass density for both ergosterol content and beta-N-acetylhexosaminidase activity. The same two mold species were inoculated onto wallpapered gypsum board, from which a direct biomass measurement...

  4. Materials Research Society, Symposium Proceedings, Volume 521. Porous and Cellular Materials for Structural Applications

    Science.gov (United States)

    2007-11-02

    blowing agent at 680°C. After stirring, the molten material is cured to expand and fill up the mold for about 15 minutes. Then, the foamed molten...closed cell cellular solids. A "perfect" model is first discussed and shown to predict the behavior of PVC foams well. However, this model over...variations (Section VI), and non-uniform cell shapes (Section VII). Fig. 1. Micro graphs of Divinycell [7] HI30 expanded PVC (left) and Alporas [8

  5. MoldFlow软件在梳子注射模结构改进及其成型缺陷分析中的应用%The Application of MoldFlow Software in the Structure Improvement and Analysis of forming Defects of Comb Injection Molding

    Institute of Scientific and Technical Information of China (English)

    陈叶娣

    2012-01-01

    MoldFlow software is applied to improve the mold structure and solve molding defects according to the problems of comb injection molding during trying mold. These will be provided some valuable references. Aunusual power is provided for the wide application of MoldFlow software in the design of injection mold.%根据梳子注射模在试模过程中存在的一些问题,采用MoldFlow软件进行分析,为改进模具结构、解决其成型缺陷提供有价值的参考。

  6. Validation of precision powder injection molding process simulations using a spiral test geometry

    DEFF Research Database (Denmark)

    Marhöfer, Maximilian; Müller, Tobias; Tosello, Guido;

    2015-01-01

    Like in many other areas of engineering, process simulations find application in precision injection molding to assist and optimize the quality and design of precise products and the molding process. Injection molding comprises mainly the manufacturing of plastic components. However, the variant ...

  7. Injection molding of nanopatterned surfaces in the sub-micrometer range with induction heating aid

    DEFF Research Database (Denmark)

    Menotti, Stefano; Hansen, Hans Nørgaard; Bissacco, Giuliano

    2014-01-01

    Replication of sub-micrometer structures by injection molding leads to special requirements for the mold in order to ensure proper replica and acceptable cycle time. This paper investigates the applicability of induction heating embedded into the mold for the improvement of nanopattern replicatio...

  8. Three-dimensional numerical modeling of an induction heated injection molding tool with flow visualization

    DEFF Research Database (Denmark)

    Guerrier, Patrick; Tosello, Guido; Nielsen, Kaspar Kirstein

    2016-01-01

    Using elevated mold temperature is known to have a positive influence of final injection molded parts. Induction heating is a method that allow obtaining a rapid thermal cycle, so the overall molding cycle time is not increased. In the present research work, an integrated multi-turn induction hea...

  9. Differential allergy induction by molds found in water-damaged homes**

    Science.gov (United States)

    Molds are ubiquitous in the environment and exposures to molds contribute to various human diseases including allergic lung diseases. The Institute of Medicine reports (NAS, 2004) and World Health Organization guidelines (WHO, 2009) concluded that the role of molds in asthma indu...

  10. Experimental Investigation of Comparative Process Capabilities of Metal and Ceramic Injection Molding for Precision Applications

    DEFF Research Database (Denmark)

    Islam, Aminul; Giannekas, Nikolaos; Marhöfer, David Maximilian;

    2016-01-01

    The purpose of this paper is to make a comparative study on the process capabilities of the two branches of the powder injection molding (PIM) process—metal injection molding (MIM) and ceramic injection molding (CIM), for high-end precision applications. The state-of-the-art literature does not m...

  11. The history of molded fiber packaging: a 20th century pulp story

    NARCIS (Netherlands)

    Wever, R.; Twede, D.

    2007-01-01

    Molded fiber packaging, which is also referred to as molded pulp packaging, has been around for a little over a hundred years now. From the first patent, dating from 1903, until approximately 25 years ago molded fiber packaging was a niche product used mainly for packing eggs. However, in the last t

  12. 40 CFR Appendix - Alternative Organic HAP Emissions Limits for Open Molding, Centrifugal Casting, and SMC...

    Science.gov (United States)

    2010-07-01

    ... Limits for Open Molding, Centrifugal Casting, and SMC Manufacturing Operations Where the Standards Are..., Table 5 Alternative Organic HAP Emissions Limits for Open Molding, Centrifugal Casting, and SMC... casting—CR/HS 3,4 A vent system that moves heated air through the mold 27 lb/ton. 8. Centrifugal...

  13. Nanostructured cellular networks.

    Science.gov (United States)

    Moriarty, P; Taylor, M D R; Brust, M

    2002-12-01

    Au nanocrystals spin-coated onto silicon from toluene form cellular networks. A quantitative statistical crystallography analysis shows that intercellular correlations drive the networks far from statistical equilibrium. Spin-coating from hexane does not produce cellular structure, yet a strong correlation is retained in the positions of nanocrystal aggregates. Mechanisms based on Marangoni convection alone cannot account for the variety of patterns observed, and we argue that spinodal decomposition plays an important role in foam formation.

  14. Packing parameters effect on injection molding of polypropylene nanostructured surfaces

    DEFF Research Database (Denmark)

    Calaon, Matteo; Tosello, Guido; Hansen, Hans Nørgaard

    2012-01-01

    having a diameter of 500 nm was employed. The tool insert surface was produced using chemical-based-batch techniques such aluminum anodization and nickel electroplating. During the injection molding process, polypropylene (PP) was employed as material and packing phase parameters (packing time, packing...... to the polymer part was mainly influenced by packing pressure level and distance from the gate....

  15. On the Injection Molding of Nanostructured Polymer Surfaces

    DEFF Research Database (Denmark)

    Pranov, Henrik; Rasmussen, Henrik K.; Larsen, Niels Bent;

    2006-01-01

    Well-defined nano-topographies were prepared by electron-beam lithography and electroplated to form nickelshims. The surface pattern consisted of square pillars repeated equidistantly within the plane of the surface in a perpendicular arrangement. The width and distance between the squares both...... mold sub-micrometer surface structures in polymers mainly relates to adhesive energy between polymer and shim....

  16. QTLs for Snow Mold Disease Resistance in Creeping Bentgrass

    Science.gov (United States)

    Snow molds caused by Typhula spp. are the most economically important winter diseases of turfgrass in the northern and alpine regions of the United States and Canada. During winter, the psychrophilic pathogens take advantage of the weakened host plants at low temperatures under persistent snow cover...

  17. Metal Injection Molding of Alloy 718 for Aerospace Applications

    Science.gov (United States)

    Ott, Eric A.; Peretti, Michael W.

    2012-02-01

    The metal injection molding process, used in the automotive, medical, and consumer markets for several decades, was investigated for application to superalloys for small, complex-shaped, aerospace components. With sufficient control on processing, inclusion risks, and chemistry, the process can successfully be applied to superalloy 718 components. Assessments included tensile and fatigue property evaluation, characterization of microstructure, and development of an AMS specification.

  18. Engineering Design Handbook Rotational Molding of Plastic Powders

    Science.gov (United States)

    1975-04-15

    nozzle make up the facility for liquid honing for finishing molds. If pickling is desired, acid and water tanks, and a small heating system are all...pigments or filler materials. Certain pigments such as carbon black and titanium dioxide (white) are very hard to disperse by dry blending. Low

  19. Advanced Polymer Composite Molding Through Intelligent Process Analysis and Control

    Science.gov (United States)

    2004-11-30

    In this project. process analysis of Resin Transfer Molding (RTM) was carried out and adaptive process control models were developed. In addition, a...aforementioned work in three separate sections: (1) process analysis and adaptive control modeling, (2) manufacturing of non-invasive sensor, end (3) list of publications resulting from this project.

  20. Precision glass molding: Toward an optimal fabrication of optical lenses

    Science.gov (United States)

    Zhang, Liangchi; Liu, Weidong

    2016-12-01

    It is costly and time consuming to use machining processes, such as grinding, polishing and lapping, to produce optical glass lenses with complex features. Precision glass molding (PGM) has thus been developed to realize an efficient manufacture of such optical components in a single step. However, PGM faces various technical challenges. For example, a PGM process must be carried out within the super-cooled region of optical glass above its glass transition temperature, in which the material has an unstable non-equilibrium structure. Within a narrow window of allowable temperature variation, the glass viscosity can change from 105 to 1012 Pas due to the kinetic fragility of the super-cooled liquid. This makes a PGM process sensitive to its molding temperature. In addition, because of the structural relaxation in this temperature window, the atomic structure that governs the material properties is strongly dependent on time and thermal history. Such complexity often leads to residual stresses and shape distortion in a lens molded, causing unexpected changes in density and refractive index. This review will discuss some of the central issues in PGM processes and provide a method based on a manufacturing chain consideration from mold material selection, property and deformation characterization of optical glass to process optimization. The realization of such optimization is a necessary step for the Industry 4.0 of PGM.

  1. Effective Control of Molds Using a Combination of Nanoparticles

    Science.gov (United States)

    Martínez-Castañón, Gabriel Alejandro; Slavin, Yael N.; Zhao, Wayne; Asnis, Jason; Häfeli, Urs O.

    2017-01-01

    Molds are filamentous fungi able to grow on a variety of surfaces, including constructed surfaces, food, rotten organic matter, and humid places. Mold growth is characterized by having an unpleasant odor in enclosed or non-ventilated places and a non-aesthetic appearance. They represent a health concern because of their ability to produce and release mycotoxins, compounds that are toxic to animals and humans. The aim of this study was to evaluate commercial nanoparticles (NPs) that can be used as an additive in coatings and paints to effectively control the growth of harmful molds. Four different NPs were screened for their antifungal activities against the mycotoxin producing mold strains Aspergillus flavus and A. fumigatus. The minimal inhibitory concentrations of the NPs were determined in broth media, whereas an agar diffusion test was used to assess the antimold activity on acrylic- and water-based paints. The cytotoxic activity and the inflammatory response of the NPs were also evaluated using the established human derived macrophage cell line THP-1. Results showed that a combination of mix metallic- and ZnO-NPs (50:10 μg/mL) effectively inhibited the fungal growth when exposed to fluorescent light. Neither cytotoxic effect nor inflammatory responses were recorded, suggesting that this combination can be safely used in humid or non-ventilated environments without any health concerns. PMID:28122038

  2. Stability of FDTS monolayer coating on aluminum injection molding tools

    Energy Technology Data Exchange (ETDEWEB)

    Cech, Jiri [Department of Micro- and Nanotechnology, Technical University of Denmark, DTU Nanotech, Building 345E, DK-2800 Kongens Lyngby (Denmark); Taboryski, Rafael, E-mail: rafael.taboryski@nanotech.dtu.dk [Department of Micro- and Nanotechnology, Technical University of Denmark, DTU Nanotech, Building 345E, DK-2800 Kongens Lyngby (Denmark)

    2012-10-15

    Highlights: Black-Right-Pointing-Pointer We present novel and highly useful results on FDTS monolayer coating of aluminum. Black-Right-Pointing-Pointer The coating is particularly applicable for coating of prototyping injection molding tools, which often are made of Al. Black-Right-Pointing-Pointer We have demonstrated that the coating prevails in injection molding conditions and that the coating will prevent wear of the tools. - Abstract: We have characterized perfluorodecyltrichlorosilane (FDTS) molecular coating of aluminum molds for polymer replication via injection molding (IM). X-ray photoelectron spectroscopy (XPS) data, sessile drop contact angles with multiple fluids, surface energies and roughness data have been collected. Samples have been characterized immediately after coating, after more than 500 IM cycles to test durability, and after 7 months to test temporal stability. The coating was deposited in an affordable process, involving near room temperature gas phase reactions. XPS shows detectable fluorine presence on both freshly coated samples as well as on post-IM samples with estimated 30 at.% on freshly coated and 28 at.% on post-IM samples with more than 500 IM cycles with polystyrene (PS) and ABS polymer.

  3. A Recurrent Neural Network for Warpage Prediction in Injection Molding

    Directory of Open Access Journals (Sweden)

    A. Alvarado-Iniesta

    2012-11-01

    Full Text Available Injection molding is classified as one of the most flexible and economical manufacturing processes with high volumeof plastic molded parts. Causes of variations in the process are related to the vast number of factors acting during aregular production run, which directly impacts the quality of final products. A common quality trouble in finishedproducts is the presence of warpage. Thus, this study aimed to design a system based on recurrent neural networksto predict warpage defects in products manufactured through injection molding. Five process parameters areemployed for being considered to be critical and have a great impact on the warpage of plastic components. Thisstudy used the finite element analysis software Moldflow to simulate the injection molding process to collect data inorder to train and test the recurrent neural network. Recurrent neural networks were used to understand the dynamicsof the process and due to their memorization ability, warpage values might be predicted accurately. Results show thedesigned network works well in prediction tasks, overcoming those predictions generated by feedforward neuralnetworks.

  4. Thermal modeling of wafer-based precision glass molding process

    Science.gov (United States)

    Hu, Yang; Shen, Lianguan; Zhou, Jian; Li, Mujun

    2016-10-01

    Wafer based precision glass optics manufacturing has been an innovative approach for combining high accuracy with mass production. However, due to the small ratio of thickness and diameter of the glass wafer, deformation and residual stress would be induced for the nonuniform temperature distribution in the glass wafer after molding. Therefore, thermal modelling of the heating system in the wafer based precision glass molding (PGM) process is of great importance in optimizing the heating system and the technique of the process. The current paper deals with a transient thermal modelling of a self-developed heating system for wafer based PGM process. First, in order to investigate the effect of radiation from the surface and interior of the glass wafer, the thermal modeling is simulated with a discrete ordinates radiation model in the CFD software FLUENT. Temperature distribution of the glass wafer obtained from the simulations is then used to evaluate the performance of heating system and investigate some importance parameters in the model, such as interior and surface radiation in glass wafer, thermal contact conductance between glass wafer and molds, thickness to diameter ratio of glass wafer. Finally, structure modification in the molding chamber is raised to decrease the temperature gradient in the glass wafer and the effect is significant.

  5. Optimizing biomass blends for manufacturing molded packaging materials using mycelium

    Science.gov (United States)

    Polystyrene is one of the most widely used plastics and is commonly produced in three forms: 1) Extruded polystyrene – disposable utensils, CD/DVD cases, yogurt containers, smoke alarm housing, etc.; 2) Expanded polystyrene foam – molded packaging materials and packaging "peanuts"; 3) Extruded polys...

  6. 铜阳极泥综合回收技术研究%Study on Comprehensive Utilization Technique of Copper Anode Slime

    Institute of Scientific and Technical Information of China (English)

    王俊娥

    2013-01-01

    以某铜冶炼厂电解铜阳极泥为原料,对预处理脱铜、硒和碲-浸出渣碳酸钠转化-醋酸浸出铅-除铅渣氯化分金-分金渣亚硫酸钠浸银的阳极泥综合回收工艺进行了详细的研究,结果表明:通过选取合适工艺技术参数,可使金、银、铜、铅、硒、碲的浸出率分别达到:99.23%、99.58%、99.30%、93.96%、86.11%、89.58%。%his paper reports the detailed research on comprehensive utilization of copper anode slime from a copper smeltery.And the main technological processes are:removal of Cu,Se and Te, then transforming lead sulfate to lead carbonate with natronite followed by ethylic acid leaching , then chlorination and extraction of gold , and then leaching of Ag with sodium sulfite .The results show that the leaching rates of Au, Ag, Cu, Pb, Se and Te can reach to 99.23%, 99.58%, 99.30%, 93 .96%, 86 .11%and 89 .58%respectively on proper condition.

  7. Analysis on the TBS coarse slime separation effect of Xinyang coal preparation plant%新阳选煤厂TBS粗煤泥分选效果分析

    Institute of Scientific and Technical Information of China (English)

    李鹏; 张文志; 赵建刚; 朱立强

    2012-01-01

      新阳选煤厂整体工程分两期完成,分别采用不同的分选工艺。文中详述了TBS粗煤泥分选机的工作原理和实际生产的分选效果。通过分析发现,粗煤泥利用TBS分选后精矿灰分波动相对较小,能满足生产需要,但对入料的适应性差,入料变化时,精煤损失到尾矿中,造成尾煤灰分波动较大。%  the Xinyang coal separation plant overall project completed in two phases, using different separation process. This paper intro-duces the working principle and the actual production of the separation effect of coarse slime separation equipment —TBS. Through the analysis we found that, The ash of Concentrate has smaller fluctions by using TBS. It can meet the need of production.But the adaptability of TBS is not good.,When the feeding is changing large amounts of coal loss to the tailings and the ash of coal tailing havs large fluctuation

  8. 新阳选煤厂粗煤泥分选设备评述%Commentary of coarse slime separation equipment of Xinyang coal preparation plant

    Institute of Scientific and Technical Information of China (English)

    李鹏; 张文志; 赵建刚; 朱立强

    2012-01-01

      新阳选煤厂整体工程分两期完成,分别采用不同的分选工艺。文中详述了TBS和RC两种粗煤泥分选设备的工作原理和实际生产的分选效果。两者对比发现,入料发生波动时造成尾煤产品质量不合格,大量精煤损失到尾矿中。相对RC分选机,TBS的适应性稍好。%  the Xinyang coal separation plant overall project completed in two phases, using different separation process. This paper intro-duces the working principle and the actual production of the separation effect of two kinds of coarse slime separation equipment —TBS and RC. The contrast between the two found, feeding fluctuations caused by tail coal product quality, large amounts of coal loss to the tailings. Relative to the RC sorting machine, TBS adaptability slightly better.

  9. Incipient flocculation molding: A new ceramic-forming technique

    Science.gov (United States)

    Arrasmith, Steven Reade

    Incipient Flocculation Molding (IFM) was conceived as a new near-net-shape forming technique for ceramic components. It was hypothesized that the development of a temperature-dependent deflocculant would result in a forming technique that is flexible, efficient, and capable of producing a superior microstructure with improved mechanical properties from highly reactive, submicron ceramic powders. IFM utilizes a concentrated, nonaqueous, sterically stabilized ceramic powder and/or colloidal suspension which is injected into a non-porous mold. The suspension is then flocculated by destabilizing the suspension by lowering the temperature. Flocculation is both rapid and reversible. Cooling to -20°C produces a green body with sufficient strength for removal from the mold. The solvent is removed from the green body by evaporation. The dried green body is subsequently sintered to form a dense ceramic monolith. This is the first ceramic forming method based upon the manipulation of a sterically-stabilized suspension. To demonstrate IFM, the process of grafting polyethylene glycol (PEG), with molecular weights from 600 to 8000, to alumina powders was investigated. The maximum grafted amounts were achieved by the technique of dispersing the alumina powders in molten polymer at 195°C. The ungrafted PEG was then removed by repeated centrifuging and redispersion in fresh distilled water. The rheological behavior of suspensions of the PEG-grafted powders in water, 2-propanol and 2-butanol were characterized. All of the aqueous suspensions were shear thinning. The PEG 4600-grafted alumina powder aqueous suspensions were the most fluid. Sample rods and bars were molded from 52 vol% PEG-grafted alumina suspensions in 2-butanol. The best results were obtained with a preheated aluminum mold lubricated with a fluorinated oil mold-release. The samples were dried, sintered, and their microstructure and density were compared with sintered samples dry pressed from the same alumina powder

  10. Species identification, slime production and oxacillin susceptibility in coagulase-negative staphylococci isolated from nosocomial specimens Identificação de espécies, produção de "slime" e sensibilidade a oxacilina em amostras de Staphylococcus coagulase-negativo isoladas de espécimes nosocomiais

    Directory of Open Access Journals (Sweden)

    Lucía E. Alcaráz

    2003-04-01

    Full Text Available Ninety-two coagulase negative staphylococci (CNS (forty-five of clinical origin and forty-seven of environmental origin, collected in a hospital in San Luis, Argentina, from March to June, 1999, were identified to species level by the ID 32 Staph and API Staph System (bioMérieux. Slime production was investigated by the quantitative and qualitative methods. Oxacillin susceptibility was determined by the disk diffusion test (1 µg, the agar dilution method (0.125 to 4 mg/ml and agar screen (6 µg/ml. The presence of mecA gene was investigated by PCR. The clinical CNS species most commonly isolated were S. epidermidis, S. haemolyticus, S. hominis and S. saprophyticus. The frequency of slime production by clinical and environmental isolates was similar (25/45 and 27/47, respectively and the results obtained by the quantitative and the qualitative methods correlated well. The mecA gene was detected in all S. epidermidis, S. haemolyticus and S. hominis isolates, which were resistant to oxacillin by the phenotypic methods. However, this gene was not present in S. klossii, S. equorum, S. xylosus and S. capitis strains. The gene was neither found in two out of the six S. saprophyticus isolates, in two out of three S. cohnii subsp. urealyticum isolates and in two out of five S. cohnii subsp. cohnii isolates, all of which resulted oxacillin resistant according to MIC. The gene was not found in oxacillin-susceptible strains either. Most of the CNS isolates (enviromental and clinical that were slime producers were found to be oxacillin resistant, which makes the early detection of these microorganisms necessary to prevent their dissemination in hospitals, particularly among immunocompromised patients.Noventa e duas amostras de Staphylococcus coagulase negativo (SCN, (45 amostras clínicas e 47 ambientais, coletadas em um hospital de San Luis, Argentina, durante o período de março a junho de 1999, foram identificadas até espécies, empregando-se os

  11. Raw Coal Density Affected to Surface Zeta Potential of Muddy and Slime Particle%原煤密度对泥化及煤泥颗粒表面ξ电位的影响

    Institute of Scientific and Technical Information of China (English)

    赵晴; 闵凡飞; 刘令云; 李宏亮

    2011-01-01

    The muddy experiment on 50 -0.5 mm different density raw coal from Dingji Coal Preparation Plant of Huainan Mining Area was conducted. The X-ray diffractor and the electrophoresis experiment was individually applied to measure the raw coal mineral composition and the zeta potential on the micro particle surface of the slime. The results showed that the main mineral composition of the raw coal to be prepared would be including quartz, kaolinite, green mudstone and others. The muddy rate of the high density and medium density raw coal was high. In the muddy slime of the +1. 60 g/cmJ raw coal, the -0. 045 mm particles would be the majority and the -0. 025 mm micro particles would be over 90%. With the raw coal density increased and the slime particle reduced, the zeta potential on the micro particle surface of the muddy slime would be reduced in potential. The water hardness, the soluble salt in the raw coal and the particle surface property would have important influence to the zeta potential occurred on the slime micro particle. The zeta potential increased on the slime micro particle surface would cause the particles in the slime water in more stable dispersed state.%对淮南矿区丁集选煤厂50~0.5 mm不同密度级原煤进行了泥化试验,采用X-射线衍射 仪和电泳试验分别对原煤矿物组成和煤泥微细颗粒表面ξ电位进行了测定.结果表明:入选原煤中主要矿物成分有石英、高岭石、绿泥石等;高密度和中间密度级原煤泥化率大,+1.60g/cm3原煤泥化煤泥中-0.045 mm颗粒最多,其中约90%以上为-0.025 mm的微细颗粒;随着原煤密度的增大和煤泥粒度的减小,泥化煤泥微细颗粒表面ξ电位呈减小趋势,水的硬度、原煤中可溶性盐及颗粒表面性质对煤泥微细颗粒ξ电位产生重要影响,微细煤泥颗粒表面ξ电位增大会导致其在煤泥水中处于更加稳定的分散状态.

  12. Solidification process and infrared image characteristics of permanent mold castings

    Science.gov (United States)

    Viets, Roman; Breuer, Markus; Haferkamp, Heinz; Kruessel, Thomas; Niemeyer, Matthias

    1999-03-01

    Interdependence between the development of temperature gradients at the solid-liquid interface during solidification of metals and the formation of local defects demands for thermal investigation. In foundry practice thermocouples are used to control the die's overall cooling-rate, but fluctuations in product quality still occur. Capturing FIR- thermograms after opening the die visualizes the state, when most thermal throughput has already flattened the temperature gradients in the mold. Rapid dissipation of heat from liquid metal to the mold during solidification forces further approach of the process investigation by slowing down the heat flux or the use of transparent mold material. Aluminum gravity casting experiments under technical vacuum conditions lead to decelerated solidification by suppression of convection and image sequences containing explicit characteristics that could be assigned to local shrinkage of the casting. Hence relevant clusters are extracted and thermal profiles are drawn from image series, pointing out correlations between feeding performance from the sink heads and the appearance of local defects. Tracing thermal processes in vacuum casting can scarcely be transferred to image data in foundry practice, since only little analogies exist between atmospheric and vacuum casting. The diagnosis of the casting process requires detection of the still closed mold using a transparent silica- aerogel sheet as part of the die. Hereby thermograms of the initial heat input are recorded by adapting a NIR-camera in addition to the FIR-unit. Thus the entire thermal compensation at the joint face for each casting is visualized. This experimental set-up is used for image sequence analysis related to the intermediate casting phases of mold filling, body formation and solidification shrinkage.

  13. Estudio experimental del llenado de moldes pulvimetalúrgicos

    Directory of Open Access Journals (Sweden)

    Istúriz, A.

    2005-12-01

    Full Text Available Die filling is the first step in the process of powder compaction. The density distribution depends of the powder characteristics and method of filling. In this work we present the first results obtained with different experimental methods of the filling. Results have been analyzed using a video system which permits the observation of the powder flow. The aim of the work is to determinate the effects of size, morphology and nature of the powder, as well as shoe speed, and die geometry on the apparent density distribution in industrial dies of complex geometry.

    En el proceso de conformado pulvimetalúrgico, la consolidación del polvo se inicia con el llenado del molde en el que se fabricará la preforma porosa, el cual está caracterizado por la distribución de densidades del polvo dentro del molde y depende tanto de las propiedades del mismo como del método de llenado utilizado. A continuación, presentamos los primeros resultados obtenidos mediante un montaje experimental que reproduce el llenado de moldes y que, empleando un sistema de video, permite analizar el flujo de las partículas durante el llenado. El objetivo es determinar el efecto del tamaño, naturaleza y morfología del polvo, así como el de la velocidad del cargador y la geometría del molde en la distribución de la densidad aparente en moldes industriales de geometría compleja.

  14. Molding Properties of Inconel 718 Feedstocks Used in Low-Pressure Powder Injection Molding

    Directory of Open Access Journals (Sweden)

    Fouad Fareh

    2016-01-01

    Full Text Available The impact of binders and temperature on the rheological properties of feedstocks used in low-pressure powder injection molding was investigated. Experiments were conducted on different feedstock formulations obtained by mixing Inconel 718 powder with wax-based binder systems. The shear rate sensitivity index and the activation energy were used to study the degree of dependence of shear rate and temperature on the viscosity of the feedstocks. The injection performance of feedstocks was then evaluated using an analytical moldability model. The results indicated that the viscosity profiles of feedstocks depend significantly on the binder constituents, and the secondary binder constituents play an important role in the rheological behavior (pseudoplastic or near-Newtonian exhibited by the feedstock formulations. Viscosity values as low as 0.06 to 2.9 Pa·s were measured at high shear rates and high temperatures. The results indicate that a feedstock containing a surfactant agent exhibits the best moldability characteristics.

  15. Effects of Process Parameters on Replication Accuracy of Microinjection Molded Cyclic Olefins Copolymers Parts

    Science.gov (United States)

    Lin, Hsuan-Liang; Chen, Chun-Sheng; Lee, Ruey-Tsung; Chen, Shia-Chung; Chien, Rean-Der; Jeng, Ming-Chang; Hwang, Jiun-Ren

    2013-04-01

    In this study, the effects of various processing parameters of microinjection molding on the replication accuracy of the micro featured fluidic platform used for DNA/RNA tests are investigated. LIGA-like processes were utilized to prepare a silicon-based SU-8 photoresist, followed by electroforming to make a Ni-Co-based stamp. A cyclic olefin copolymer (COC) was used as the injection molding material. The molding parameters associated with the replication accuracy of micro channel parts were investigated. It was found that for microinjection molded devices, the replication accuracies of the imprint width and depth increase with increasing of mold temperature, melt temperature, injection velocity, and packing pressure.

  16. Measurement of casting parameters in ZnAlCu3 molds created by additive technology

    Directory of Open Access Journals (Sweden)

    S. Medić

    2016-10-01

    Full Text Available This paper examines the parameters of casting ZnAl4Cu3 alloy (volume, castability, density and occupancy of the mold in mold made additive technology. Molds made by additive technology are: cheaper in production of a small number of castings, geometrically more accurate and faster made. From obtained results of this paper it is clearly seen that printed mold must be protected with thermal coating because liquid adhesive of powder otherwise evaporates during casting and creates additional moisture in the mold, as it was noted.

  17. Computer precision simulation for titanium casting centrifugal mold filling of prescision titanium castings

    Directory of Open Access Journals (Sweden)

    Daming XU

    2004-08-01

    Full Text Available Computer simulation codes were developed based on proposed mathematical model for centrifugal mold filling processes and previous computer software for 3D mold filling and solidification of castings. Sample simulations were implemented for mold filling processes of precision titanium castings under gravity and different centrifugal casting techniques. The computation results show that the alloy melt has a much stronger mold filling ability for thin section castings unde a centrifugal force field than that only under the gravity. A "return back" mold filling manner is showed to be a reasonable technique for centrifugal casting processes, especially for thin section prcision castings.

  18. Investigation of micro-injection molding based on longitudinal ultrasonic vibration core.

    Science.gov (United States)

    Qiu, Zhongjun; Yang, Xue; Zheng, Hui; Gao, Shan; Fang, Fengzhou

    2015-10-01

    An ultrasound-assisted micro-injection molding method is proposed to improve the rheological behavior of the polymer melt radically, and a micro-injection molding system based on a longitudinal ultrasonic vibration core is developed and employed in the micro-injection molding process of Fresnel lenses. The verification experiments show that the filling mold area of the polymer melt is increased by 6.08% to 19.12%, and the symmetric deviation of the Fresnel lens is improved 15.62% on average. This method improved the filling performance and replication quality of the polymer melt in the injection molding process effectively.

  19. Temperature and Thermal Stress Distribution for Metal Mold in Squeeze Casting Process

    Institute of Scientific and Technical Information of China (English)

    K.H.Chang; G.C.Jang; C.H.Lee; S.H.Lee

    2008-01-01

    In the squeeze casting process, loaded high pressure (over approximately 100 MPa) and high temperature influence the thermo-mechanical behavior and performance of the used metal mold. Therefore, to safely maintain the metal molds, the thermo-mechanical characteristics (temperature and thermal stress) of metal mold in the squeeze casting must be investigated. In this paper, temperature and thermal stress distribution of steel mold in squeeze casting process were investigated by using a three-dimensional non-steady heat conduction analysis and a three-dimensional thermal elastic-plastic analysis considering temperature-dependent thermo- physical and mechanical properties of the steel mold.

  20. Strength analysis and modeling of cellular lattice structures manufactured using selective laser melting for tooling applications

    DEFF Research Database (Denmark)

    Mahshid, Rasoul; Hansen, Hans Nørgaard; Loft Højbjerre, Klaus

    2016-01-01

    Additive manufacturing is rapidly developing and gaining popularity for direct metal fabrication systems like selective laser melting (SLM). The technology has shown significant improvement for high-quality fabrication of lightweight design-efficient structures such as conformal cooling channels...... in injection molding tools and lattice structures. This research examines the effect of cellular lattice structures on the strength of workpieces additively manufactured from ultra high-strength steel powder. Two commercial SLM machines are used to fabricate cellular samples based on four architectures— solid...

  1. Effects of centrifugal and Coriolis forces on the mold-filling behavior of titanium melts in vertically rotating molds

    Institute of Scientific and Technical Information of China (English)

    Xu Daming; Jia Limin; Fu Hengzhi

    2008-01-01

    The vertical centrifugal-casting technique is widely used in the manufacture of various irregularly-shaped castings of advanced structural alloys with thin walls, complex shapes and/or large sizes. These castings are used in the increasing applications in aero-space/aviation industries, human teeth/bone repairs with near-net shaped components, etc. In a vertically rotating casting system, the mold-filling processes of alloy melts, coupled with solidification-heat transfer, may be much more complicated, because they are driven simultaneously by gravity, centrifugal and Codolis forces. In the present work, an N-S/VOF-equations-based model, solved using a SOLA-VOF algorithm, under a rotating coordinate system was applied to numerically investigate the impacts of centrifugal and Coriolis forces on metallic melt mold-filling processes in different vertical centrifugal-casting configurations with different mold-rotation rates using an authors' computer-codes system. The computational results show that the Coriolis force may cause remarkable variations in the flow patterns in the casting-part-cavities of a large horizontal-section area and directly connected to the sprue via a short ingate in a vertical centrifugal-casting process. A "turn-back" mold-filling technique, which only takes advantage of the centrifugal force in a transient rotating melt system, has been confirmed to be a rational centrifugal-casting process in order to achieve smooth and layer-by-layer casting-cavities-filling control. The simulated mold-filling processes of Ti-6Al-4V alloy melt, in a vertical centrifugal-casting system with horizontally-connected plate-casting cavities, show reasonable agreement with experimental results from the literature.

  2. Precision molding of advanced glass optics: innovative production technology for lens arrays and free form optics

    Science.gov (United States)

    Pongs, Guido; Bresseler, Bernd; Bergs, Thomas; Menke, Gert

    2012-10-01

    Today isothermal precision molding of imaging glass optics has become a widely applied and integrated production technology in the optical industry. Especially in consumer electronics (e.g. digital cameras, mobile phones, Blu-ray) a lot of optical systems contain rotationally symmetrical aspherical lenses produced by precision glass molding. But due to higher demands on complexity and miniaturization of optical elements the established process chain for precision glass molding is not sufficient enough. Wafer based molding processes for glass optics manufacturing become more and more interesting for mobile phone applications. Also cylindrical lens arrays can be used in high power laser systems. The usage of unsymmetrical free-form optics allows an increase of efficiency in optical laser systems. Aixtooling is working on different aspects in the fields of mold manufacturing technologies and molding processes for extremely high complex optical components. In terms of array molding technologies, Aixtooling has developed a manufacturing technology for the ultra-precision machining of carbide molds together with European partners. The development covers the machining of multi lens arrays as well as cylindrical lens arrays. The biggest challenge is the molding of complex free-form optics having no symmetrical axis. A comprehensive CAD/CAM data management along the entire process chain is essential to reach high accuracies on the molded lenses. Within a national funded project Aixtooling is working on a consistent data handling procedure in the process chain for precision molding of free-form optics.

  3. EXPERIMENTAL RESEARCH AND NUMERICAL SIMULATION OF MOLD TEMPERATURE FIELD IN CONTINUOUS CASTING OF STEEL

    Institute of Scientific and Technical Information of China (English)

    X.S. Zheng; M.H. Sha; J.Z. Jin

    2006-01-01

    Mold is the heart of the continuous casting machine. Heat transfer and solidification in a watercooled mold are the most important factors during the continuous casting of steel. For studying the temperature distribution of a mold wall, a simulated apparatus of mold was designed and experiments were performed by it. The measured results indicated that the mold wall temperature approaches the temperature of cooling-water. An equivalent thermal-conductivity coefficient was proposed and deduced on the basis of the conclusion of the experiments. This coefficient was applied to solve the heat transfer between the melt and cooling water, and to characterize the heat transfer capacity of the mold. By this equivalent thermal-conductivity coefficient, it is very easy and convenient to numerically simulate the solidification process of continuous casting. And the calculation results are in agreement with the experiments. The effects of casting speed and water flow rate on the mold temperature field were also discussed.

  4. Analysis of the origin of periodic oscillatory flow in the continuous casting mold

    Science.gov (United States)

    Lee, Jun-young; Kim, Yong-tae; Yi, Kyung-woo

    2015-03-01

    It is very important to understand flow patterns within the continuous casting mold because they have a significant impact on product quality. Water model experiment and particle image velocimetry were conducted to identify the fluid flow pattern in the steel slab continuous casting mold. The fluid flow pattern in the mold is not steady but instead an oscillatory flow with a specific oscillation frequencies. Many studies have been reported about oscillatory flow within the mold. However, these studies do not provide a clear explanation of physical origin of oscillatory flow. We identified the physical origins of various specific oscillation frequencies, and confirmed through experimentation and simulation that each frequency is related to the cross flow and injection stream oscillation. Moreover, the degree of oscillation at each frequency appears differently depending on the location within the mold, and is shown to have a effect near the mold wall. These results provide a better understanding of complex oscillatory flow patterns within the mold.

  5. Modeling and flow analysis of pure nylon polymer for injection molding process

    Science.gov (United States)

    Nuruzzaman, D. M.; Kusaseh, N.; Basri, S.; Oumer, A. N.; Hamedon, Z.

    2016-02-01

    In the production of complex plastic parts, injection molding is one of the most popular industrial processes. This paper addresses the modeling and analysis of the flow process of the nylon (polyamide) polymer for injection molding process. To determine the best molding conditions, a series of simulations are carried out using Autodesk Moldflow Insight software and the processing parameters are adjusted. This mold filling commercial software simulates the cavity filling pattern along with temperature and pressure distributions in the mold cavity. In the modeling, during the plastics flow inside the mold cavity, different flow parameters such as fill time, pressure, temperature, shear rate and warp at different locations in the cavity are analyzed. Overall, this Moldflow is able to perform a relatively sophisticated analysis of the flow process of pure nylon. Thus the prediction of the filling of a mold cavity is very important and it becomes useful before a nylon plastic part to be manufactured.

  6. Fiber Reinforcement in Injection Molded Nylon 6/6 Spur Gears

    Science.gov (United States)

    Senthilvelan, S.; Gnanamoorthy, R.

    2006-07-01

    Injection molded polymer composite gears are being used in many power and or motion transmission applications. In order to widen the utilization of reinforced polymers for precision motion transmission and noise less applications, the accuracy of molded gears should be increased. Since the injection molded gear accuracy is significantly influenced by the material shrinkage behaviour, there is a need to understand the influence of fiber orientation and gate location on part shrinkage behaviour and hence the gear accuracy. Unreinforced and 20% short glass fiber reinforced Nylon 6/6 spur gears were injection molded in the laboratory and computer aided simulations of gear manufacturing was also carried out. Results of the mold flow simulation of gear manufacturing were correlated with the actual fiber orientation and measured major geometrical parameters of the molded gears. Actual orientation of the fibers near the tooth profile, weld line region and injection points of molded gears were observed using optical microscope and correlated with predicted fiber orientation.

  7. EXPERIMENTAL MEASUREMENT OF MAGNETIC FIELD IN A NOVEL FLOW CONTROL OF MOLD

    Institute of Scientific and Technical Information of China (English)

    G.J. Xu; D.H. Li; J.C. He

    2002-01-01

    In order to know the distribution of magnetic field in a novel flow control of mold(NFC Mold) and to provide the experimental data for the electromagnetic structuredesign and the analysis of flow control in continuous casting mold, the magnetic fieldin a NFC Mold were measured by Tesla meter of Model CT-3. The method of vectorsynthesis was adopted in the measurement of magnetic fields. The results showed thatthe magnetic field in the NFC Mold was composed of two main magnetic areas thatwere symmetrical. Although there was leaking magnetic flux between the lower surfaceof the upper pole and the upper surface of the lower pole on the sides, it was restrainedby the main magnetic fields effectively. Therefore the NFC Mold was more preferablysatisfied to be used in controlling the molten steel flow in continuous casting mold.

  8. Increasing the life of molds for casting copper and its alloys

    Science.gov (United States)

    Smirnov, A. N.; Spiridonov, D. V.

    2010-12-01

    The work of the molds intended for casting copper and copper alloys in semicontinuous casters for producing flat billets is considered. It is shown that, to increase the resistance of mold plates, the inner space of the mold should have a taper shape toward the casting direction and take into account the shrinkage of the linear dimensions of the ingot during its motion in the mold. The taper shape increases the intensity and uniformity of heat removal due to close contact between the ingot and the mold inner surface. Testing of new design molds under industrial conditions demonstrates that their resistance increases by a factor of 4.0-4.5. The taper effect of the mold plates is much more pronounced in their narrow faces.

  9. Epigenetics and Cellular Metabolism

    Science.gov (United States)

    Xu, Wenyi; Wang, Fengzhong; Yu, Zhongsheng; Xin, Fengjiao

    2016-01-01

    Living eukaryotic systems evolve delicate cellular mechanisms for responding to various environmental signals. Among them, epigenetic machinery (DNA methylation, histone modifications, microRNAs, etc.) is the hub in transducing external stimuli into transcriptional response. Emerging evidence reveals the concept that epigenetic signatures are essential for the proper maintenance of cellular metabolism. On the other hand, the metabolite, a main environmental input, can also influence the processing of epigenetic memory. Here, we summarize the recent research progress in the epigenetic regulation of cellular metabolism and discuss how the dysfunction of epigenetic machineries influences the development of metabolic disorders such as diabetes and obesity; then, we focus on discussing the notion that manipulating metabolites, the fuel of cell metabolism, can function as a strategy for interfering epigenetic machinery and its related disease progression as well. PMID:27695375

  10. Architected Cellular Materials

    Science.gov (United States)

    Schaedler, Tobias A.; Carter, William B.

    2016-07-01

    Additive manufacturing enables fabrication of materials with intricate cellular architecture, whereby progress in 3D printing techniques is increasing the possible configurations of voids and solids ad infinitum. Examples are microlattices with graded porosity and truss structures optimized for specific loading conditions. The cellular architecture determines the mechanical properties and density of these materials and can influence a wide range of other properties, e.g., acoustic, thermal, and biological properties. By combining optimized cellular architectures with high-performance metals and ceramics, several lightweight materials that exhibit strength and stiffness previously unachievable at low densities were recently demonstrated. This review introduces the field of architected materials; summarizes the most common fabrication methods, with an emphasis on additive manufacturing; and discusses recent progress in the development of architected materials. The review also discusses important applications, including lightweight structures, energy absorption, metamaterials, thermal management, and bioscaffolds.

  11. Cellular blue naevus

    Directory of Open Access Journals (Sweden)

    Mittal R

    2001-01-01

    Full Text Available A 31-year-old man had asymptomatic, stationary, 1.5X2 cm, shiny, smooth, dark blue nodule on dorsum of right hand since 12-14 years. In addition he had developed extensive eruption of yellow to orange papulonodular lesions on extensors of limbs and buttocks since one and half months. Investigations confirmed that yellow papules were xanthomatosis and he had associated diabetes mellitus and hyperlipidaemia. Biopsy of blue nodule confirmed the clinical diagnosis of cellular blue naevus. Cellular blue naevus is rare and its association with xanthomatosis and diabetes mellitus were interesting features of above patients which is being reported for its rarity.

  12. Composite materials molding simulation for purpose of automotive industry

    Science.gov (United States)

    Grabowski, Ł.; Baier, A.; Majzner, M.; Sobek, M.

    2016-08-01

    Composite materials loom large increasingly important role in the overall industry. Composite material have a special role in the ever-evolving automotive industry. Every year the composite materials are used in a growing number of elements included in the cars construction. Development requires the search for ever new applications of composite materials in areas where previously were used only metal materials. Requirements for modern solutions, such as reducing the weight of vehicles, the required strength and vibration damping characteristics go hand in hand with the properties of modern composite materials. The designers faced the challenge of the use of modern composite materials in the construction of bodies of power steering systems in vehicles. The initial choice of method for producing composite bodies was the method of molding injection of composite material. Molding injection of polymeric materials is a widely known and used for many years, but the molding injection of composite materials is a relatively new issue, innovative, it is not very common and is characterized by different conditions, parameters and properties in relation to the classical method. Therefore, for the purpose of selecting the appropriate composite material for injection for the body of power steering system computer analysis using Siemens NX 10.0 environment, including Moldex 3d and EasyFill Advanced tool to simulate the injection of materials from the group of possible solutions were carried out. Analyses were carried out on a model of a modernized wheel case of power steering system. During analysis, input parameters, such as temperature, pressure injectors, temperature charts have been analysed. An important part of the analysis was to analyse the propagation of material inside the mold during injection, so that allowed to determine the shape formability and the existence of possible imperfections of shapes and locations air traps. A very important parameter received from

  13. Influence of mold and substrate material combinations on nanoimprint lithography process: MD simulation approach

    Science.gov (United States)

    Yang, Seunghwa; Yu, Suyoung; Cho, Maenghyo

    2014-05-01

    A molecular dynamics (MD) study was performed to examine the effect of mold-substrate material composition on the pattern transferring and defects of the resist polymer in a thermal Nano Imprint Lithography (NIL) process. As candidate materials, single crystalline nickel (Ni), silicon (Si) and silica (SiO2, α-quartz) for the rigid mold substrate, and amorphous poly-(methylmethacrylate) (PMMA) thin film for the resist were considered for common applications in NIL processes. Three different material compositions of Si mold-Ni substrate, Ni mold-Si substrate, and quartz mold-Ni substrate were considered. In accordance with a real NIL process, a sequence of indentation-relaxation-release processes was quasi-statically simulated using isothermal ensemble simulation on tri-layer molecular structures consisting of a mold, resist, and substrate. To correlate the deformed shape and delamination of PMMA resist from the substrate in indentation and release processes, non-bond interaction energy between a rigid mold and resist was calculated for each combination of mold and substrate materials. The Si mold-Ni substrate combination shows successful pattern transfer to the resist polymer even without an anti-sticking layer as a result of the desirable balance of surface free energy for mold and substrate materials. However, Ni mold-Si substrate combination shows a critical delamination of the resist in the release process due to strong van der Waals adhesion between the resist and Ni mold. Similarly, the quartz mold-Ni substrate combination shows the same delamination in pattern transfer, but the adhesion of the resist to the quartz mold is attributed to electrostatic interaction. In order to provide guidelines for material selection in imprint-like processes where surface adsorption and wetting characteristics are critical design parameters, a simple PMMA-rigid plate model is proposed, with which consistent surface interaction characteristics in the full model NIL process

  14. Cellular rehabilitation of photobiomodulation

    Science.gov (United States)

    Liu, Timon Cheng-Yi; Yuan, Jian-Qin; Wang, Yan-Fang; Xu, Xiao-Yang; Liu, Song-Hao

    2007-05-01

    Homeostasis is a term that refers to constancy in a system. A cell in homeostasis normally functions. There are two kinds of processes in the internal environment and external environment of a cell, the pathogenic processes (PP) which disrupts the old homeostasis (OH), and the sanogenetic processes (SP) which restores OH or establishes a new homeostasis (NH). Photobiomodualtion (PBM), the cell-specific effects of low intensity monochromatic light or low intensity laser irradiation (LIL) on biological systems, is a kind of modulation on PP or SP so that there is no PBM on a cell in homeostasis. There are two kinds of pathways mediating PBM, the membrane endogenetic chromophores mediating pathways which often act through reactive oxygen species, and membrane proteins mediating pathways which often enhance cellular SP so that it might be called cellular rehabilitation. The cellular rehabilitation of PBM will be discussed in this paper. It is concluded that PBM might modulate the disruption of cellular homeostasis induced by pathogenic factors such as toxin until OH has been restored or NH has been established, but can not change homeostatic processes from one to another one.

  15. Cellular Response to Irradiation

    Institute of Scientific and Technical Information of China (English)

    LIU Bo; YAN Shi-Wei

    2011-01-01

    To explore the nonlinear activities of the cellular signaling system composed of one transcriptional arm and one protein-interaction arm, we use an irradiation-response module to study the dynamics of stochastic interactions.It is shown that the oscillatory behavior could be described in a unified way when the radiation-derived signal and noise are incorporated.

  16. Preparation of Ti-Mo getters by injection molding

    Institute of Scientific and Technical Information of China (English)

    ZHAO Zhenmei; WEI Xiuying; XIONG Yuhua; MAO Changhui

    2009-01-01

    Ti-Mo getters have been fabricated via metal injection molding (MIM) using three kinds of Ti powders with different mean particle sizes of 46 μm, 35 μm and 26 μm, respectively. The surface morphology, porosity, and hydrogen sorption properties of Ti-Mo getters formed by MIM using paraffin wax as a principal binder constituent were examined. It has been proven that the powder injection molding is a viable forming technique for porous Ti-Mo getter. The particle size of Ti powders and the powder loading influence the porosity of getters, and this affects the sorption capacity of Ti-Mo getters. Ti-Mo getters produced with the Ti powders possessing a mean particle size of 35 μm using a powder loading of 40 vol.% have a high porosity, resulting in a good sorption capacity.

  17. FPGA-Based Multiprocessor System for Injection Molding Control

    Directory of Open Access Journals (Sweden)

    Roque A. Osornio-Rios

    2012-10-01

    Full Text Available The plastic industry is a very important manufacturing sector and injection molding is a widely used forming method in that industry. The contribution of this work is the development of a strategy to retrofit control of an injection molding machine based on an embedded system microprocessors sensor network on a field programmable gate array (FPGA device. Six types of embedded processors are included in the system: a smart-sensor processor, a micro fuzzy logic controller, a programmable logic controller, a system manager, an IO processor and a communication processor. Temperature, pressure and position are controlled by the proposed system and experimentation results show its feasibility and robustness. As validation of the present work, a particular sample was successfully injected.

  18. Surviving freezing in plant tissues by oomycetous snow molds.

    Science.gov (United States)

    Murakami, Ryo; Yajima, Yuka; Kida, Ken-ichi; Tokura, Katsuyuki; Tojo, Motoaki; Hoshino, Tamotsu

    2015-04-01

    Oomyceteous snow molds, Pythium species, were reported to be less tolerant to chilling and freezing temperatures than other snow mold taxa. However, Pythium species are often found to be pathogenic on mosses in Polar Regions. We investigated the frost resistance of Pythium species from Temperate (Hokkaido, Japan) and Subantarctic Regions. Free mycelia and hyphal swellings, structures for survival, of Pythium iwayamai and Pythium paddicum lost viability within freeze-thaw 3 cycles; however, mycelia in host plants survived the treatment. It was reported that fungi in permafrost are characterized both by the presence of natural cryoprotectants in these ecotopes and by the ability to utilize their inherent mechanisms of protection. It is conceivable that plant substrates or derivatives thereof are natural cryoprotectants, enabling them to provide advantageous conditions to microorganisms under freezing conditions. Our results are the first to experimentally support this hypothesis.

  19. Pressureless sintering behavior of injection molded alumina ceramics

    Directory of Open Access Journals (Sweden)

    Liu W.

    2014-01-01

    Full Text Available The pressureless sintering behaviors of two widely used submicron alumina (MgOdoped and undoped with different solid loadings produced by injection molding have been studied systematically. Regardless of the sinterability of different powders depending on their inherent properties, solid loading plays a critical role on the sintering behavior of injection molded alumina, which greatly determines the densification and grain size, and leads to its full densification at low temperatures. As compared to the MgO-doped alumina powder, the undoped specimens exhibit a higher sinterability for its smaller particle size and larger surface area. While full densification could be achieved for MgO-doped powders with only a lower solid loading, due to the fact that MgO addition can reduce the detrimental effect of the large pore space on the pore-boundary separation.

  20. Characteristics of shell thickness in a slab continuous casting mold

    Institute of Scientific and Technical Information of China (English)

    Di-feng Wu; Shu-sen Cheng; Zi-jian Cheng

    2009-01-01

    The key to reduce shell breakout in the continuous casting process is to control shell thickness in the mold.A numerical simulation on the turbulent flow and heat transfer coupled with solidification in the slab mold using the volume of fluid (VOF) model and the enthalpy-porosity scheme was conducted and the emphasis was put upon the flow effect on the shell thickness profiles in longitudinal and transverse directions.The results show that the jet acts a stronger impingement on the shell of narrow face,which causes a zero-increase of shell thickness in a certain range near the impingement point.The thinnest shell on the slab cross-section locates primarily in the center of the narrow face,and secondly near the comer of the wide face.Nozzle optimization can obviously increase the shell thickness and make it more uniform.

  1. Injection molded polymeric hard X-ray lenses

    DEFF Research Database (Denmark)

    Stöhr, Frederik; Simons, Hugh; Jakobsen, Anders Clemen;

    2015-01-01

    A novel and economical approach for fabricating compound refractive lenses for the purpose of focusing hard X-rays is described. A silicon master was manufactured by UV-lithography and deep reactive ion etching (DRIE). Sacrificial structures were utilized, which enabled accurate control of the et......A novel and economical approach for fabricating compound refractive lenses for the purpose of focusing hard X-rays is described. A silicon master was manufactured by UV-lithography and deep reactive ion etching (DRIE). Sacrificial structures were utilized, which enabled accurate control...... of the etching profile and were removed after DRIE. By electroplating, an inverse nickel sample was obtained, which was used as a mold insert in a commercial polymer injection molding machine. A prototype lens made of polyethylene with a focal length of 350 mm was tested using synchrotron radiation at photon...

  2. Fabrication of Complex Optical Components From Mold Design to Product

    CERN Document Server

    Riemer, Oltmann; Gläbe, Ralf

    2013-01-01

    High quality optical components for consumer products made of glass and plastic are mostly fabricated by replication. This highly developed production technology requires several consecutive, well-matched processing steps called a "process chain" covering all steps from mold design, advanced machining and coating of molds, up to the actual replication and final precision measurement of the quality of the optical components. Current market demands for leading edge optical applications require high precision and cost effective parts in large volumes. For meeting these demands it is necessary to develop high quality process chains and moreover, to crosslink all demands and interdependencies within these process chains. The Transregional Collaborative Research Center "Process chains for the replication of complex optical elements" at Bremen, Aachen and Stillwater worked extensively and thoroughly in this field from 2001 to 2012. This volume will present the latest scientific results for the complete process chain...

  3. Tackification of textile preforms for resin transfer molding

    Institute of Scientific and Technical Information of China (English)

    Wuyunqiqige; YI; Xiao-su

    2005-01-01

    Tackified textile fiber preforms are used widely in resin transfer molding (RTM) to produce aerospace-grade composite parts. In the present study, a new tackifier was developed to improve RTM laminate performance. The influence of tackifier concentration on spring back, thermal properties and mechanical performance was studied . It has showed that the new tackifier was compatible with the matrix resin and improved the textile handling ability; the ILSS was slightly increased without decreasing of thermal properties, modulus and flexural strength.

  4. Presurgical nasoalveolar molding in unilateral cleft lip and palate

    Directory of Open Access Journals (Sweden)

    Rahul J Hegde

    2015-01-01

    Full Text Available Unilateral cleft lip and palate (UCLP patients have an esthetic and functional compromise of the middle third of the face and nasal structures. To improve the esthetic result of lip repair, the concept of presurgical nasoalveolar molding (PNAM was brought into conception. PNAM is an easy and passive method of bringing the alveolus and lips together by redirecting the forces of natural growth. This case report documents a 2-year follow-up of PNAM in UCLP.

  5. Numerical Simulation and Water Analog of Mold Filling Processes

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    This paper demonstrates the potential of a computer code, developed by the authors, in shaping gating systems by modeling the fluid flow phenomena through a complex gating system during mold filling. A plate casting with dimension 200 mm×200 mm×50 mm was chosen as the verifying problem. Water analog studies were carried out on this casting. The comparison indicates that computer simulation could be a powerful tool in shaping gating systems.

  6. ''Heat Transfer at the Mold-Metal Interface in Permanent Mold Casting of Aluminum Alloys'' Final Project Report

    Energy Technology Data Exchange (ETDEWEB)

    Professor R. D. Pehlke, Principal Investigator, Dr. John M. Cookson, Dr. Shouwei Hao, Dr. Prasad Krishna, Kevin T. Bilkey

    2001-12-14

    This project on heat transfer coefficients in metal permanent mold casting has been conducted in three areas. They are the theoretical study at the University of Michigan, the experimental investigation of squeeze casting at CMI-Tech Center (Now Hayes-Lemmerz Technical Center) and the experimental investigation of low pressure permanent mold casting at Amcast Automotive.

  7. Occurrence of Foodborne Pathogens and Molds in Turkish Foods

    Directory of Open Access Journals (Sweden)

    Sebnem Ozturkogu-Budak

    2016-07-01

    Full Text Available A survey of the occurrence of food pathogens like Salmonella, Listeria, Escherichia, Clostridium, Bacillus and Staphylococcus analyses were performed on 301 food samples from 8 different food categories such as dry legumes, milk products, meat products, fish, frozen foods, deserts, nuts and vegetables and fruits. Yeast and mold analyses were also performed on 364 food products from 9 main food categories such as dry legumes, milk products, meat products, seasonings, deserts, nuts, bee products, bakery products and dried fruits produced in Turkey. S. aureus and Salmonella were the most prevalent (1.33% of the six isolated pathogens. The species Cl. perfringens, L. monocytogenes and B. cereus were detected with the ratios of 1.00%, 0.66% and 0.66%, respectively. Total yeast and molds occurrence were 1.65% and 9.06%, respectively. Pathogens were detected in cream cheese, spinach, strawberry and cod fish most prevalently, whereas dried fig, chilli pepper, hazelnut and bakery products were determined as foods prone to the growth of molds. The results of this study suggest that faecal contamination of water needs to be prevented, and the production and storage conditions of food materials should be improved. These findings have implications for the use of these surveillance data in developing evidence-based food policy.

  8. Characterization of mold and moisture indicators in the home.

    Science.gov (United States)

    Mahooti-Brooks, Negar; Storey, Eileen; Yang, Chin; Simcox, Nancy J; Turner, William; Hodgson, Michael

    2004-12-01

    As studies increasingly support the presence of health risks associated with mold and moisture, understanding fungal concentrations and physical measurements as they relate to the microenvironment becomes more important. We conducted a cross-sectional study in the homes of 64 subjects. The primary objective of this study was to use trained inspectors' list of indicators in rooms (bathroom, bedroom, and basement) and determine whether these indicators are associated with higher fungal levels or physical measurements. A new category for combining the concentrations of fungal species, referred to as moisture indicator fungi (MIF), is used in the analysis. Our results show that basements with a musty odor, efflorescence, water sources, or mold have a two- to threefold increase in fungal concentrations over basements without these indicators. The regression model for the basement was highly predictive of indoor MIF concentrations (r2 = .446, p = .017). Basement water sources are substantial predictors of indoor total fungi, MIF, and Aspergillus/Penicillium spp. MIF concentrations are higher in homes with basement water sources, and most notably, the increase in MIF concentrations is significant in other living spaces (bathroom and bedroom) of the dwelling. Basement water sources are important moisture/mold indicators for epidemiologists to use in exposure assessments performed in residential dwellings.

  9. Influence of the Mold Current on the Electroslag Remelting Process

    Science.gov (United States)

    Hugo, Mathilde; Dussoubs, Bernard; Jardy, Alain; Escaffre, Jessica; Poisson, Henri

    2016-08-01

    The electroslag remelting process is widely used to produce high value-added alloys. The use of numerical simulation has proven to be a valuable way to improve its understanding. In collaboration with Aubert & Duval, the Institute Jean Lamour has developed a numerical transient model of the process. The consumable electrode is remelted within a mold assumed to be electrically insulated by the solidified slag skin. However, this assumption has been challenged by some recent studies: the solidified slag skin may actually allow a part of the melting current to reach the mold. In this paper, the evolution of our model, in order to take into account this possibility, is presented and discussed. Numerical results are compared with experimental data, while several sensitivity studies show the influence of some slag properties and operating parameters on the quality of the ingot. Even, a weakly conductive solidified slag skin at the inner surface of the mold may be responsible for a non-negligible amount of current circulating between the slag and crucible, which in turn modifies the fluid flow and heat transfer in the slag and ingot liquid pool. The fraction of current concerned depends mainly on the electrical conductivities of both the liquid and solidified slag.

  10. Drag material change in hot runner injection molding

    Institute of Scientific and Technical Information of China (English)

    蒋炳炎; 黄伯云

    2001-01-01

    Quick material change is often encountered for the different colors or kinds of polymer in hot runner injecting molding process. Time-costing and incompleteness of material change process often affects the quality and productivity of products. In the practical production, multi-injection or white material as the transition material is often adopted for quick material change. Based on the rheological behavior of the new and the previous plastic melt, the researches on the related problems were carried out. The concept of drag material change was originally presented. The physical and mathematical model on the simultaneous flow process of the new and the previous plastic melt in hot runner were built up, which can well explain the influence of the injection speed, pressure, viscosity difference, temperature and mold structure on the drag material change efficiency. When temperature in different position in the mold was increased and adjusted, the viscosity difference between the two kinds of melt can be controlled. Therefore the material change ability can be greatly improved during the whole material change process, getting rid of more and more difficult changing in the late stage.

  11. Modeling injection molding of net-shape active ceramic components.

    Energy Technology Data Exchange (ETDEWEB)

    Baer, Tomas (Gram Inc.); Cote, Raymond O.; Grillet, Anne Mary; Yang, Pin; Hopkins, Matthew Morgan; Noble, David R.; Notz, Patrick K.; Rao, Rekha Ranjana; Halbleib, Laura L.; Castaneda, Jaime N.; Burns, George Robert; Mondy, Lisa Ann; Brooks, Carlton, F.

    2006-11-01

    To reduce costs and hazardous wastes associated with the production of lead-based active ceramic components, an injection molding process is being investigated to replace the current machining process. Here, lead zirconate titanate (PZT) ceramic particles are suspended in a thermoplastic resin and are injected into a mold and allowed to cool. The part is then bisque fired and sintered to complete the densification process. To help design this new process we use a finite element model to describe the injection molding of the ceramic paste. Flow solutions are obtained using a coupled, finite-element based, Newton-Raphson numerical method based on the GOMA/ARIA suite of Sandia flow solvers. The evolution of the free surface is solved with an advanced level set algorithm. This approach incorporates novel methods for representing surface tension and wetting forces that affect the evolution of the free surface. Thermal, rheological, and wetting properties of the PZT paste are measured for use as input to the model. The viscosity of the PZT is highly dependent both on temperature and shear rate. One challenge in modeling the injection process is coming up with appropriate constitutive equations that capture relevant phenomenology without being too computationally complex. For this reason we model the material as a Carreau fluid and a WLF temperature dependence. Two-dimensional (2D) modeling is performed to explore the effects of the shear in isothermal conditions. Results indicate that very low viscosity regions exist near walls and that these results look similar in terms of meniscus shape and fill times to a simple Newtonian constitutive equation at the shear-thinned viscosity for the paste. These results allow us to pick a representative viscosity to use in fully three-dimensional (3D) simulation, which because of numerical complexities are restricted to using a Newtonian constitutive equation. Further 2D modeling at nonisothermal conditions shows that the choice of

  12. Fabrication of Composite Material Using Gettou Fiber by Injection Molding

    Science.gov (United States)

    Setsuda, Roy; Fukumoto, Isao; Kanda, Yasuyuki

    This study investigated the mechanical properties of composite using gettou (shell ginger) fiber as reinforcement fabricated from injection molding. Gettou fiber is a natural fiber made from gettou, a subtropical plant that is largely abundant in Okinawa, Japan. We used the stem part of gettou plant and made the gettou fiber by crushing the stem. The composite using gettou fiber contributed to low shrinkage ratio, high bending strength and high flexural modulus. The mechanical strength of composite using long gettou fiber showed higher value than composite using short gettou fiber. Next, because gettou is particularly known for its anti-mold characteristic, we investigated the characteristic in gettou plastic composite. The composite was tested against two molds: aspergillius niger and penicillium funiculosum. The 60% gettou fiber plastic composite was found to satisfy the JISZ2801 criterion. Finally, in order to predict the flexural modulus of composite using gettou fiber by Halpin-Tsai equation, the tensile elastic modulus of single gettou fiber was measured. The tendency of the experimental results of composite using gettou fiber was in good agreement with Halpin-Tsai equation.

  13. Penerapan Standarisasi Desain untuk Meningkatkan Kualitas dan Masa Pakai Mold Di PT. Takagi Sari Multi Utama

    Directory of Open Access Journals (Sweden)

    Andi Widodo

    2014-10-01

    Full Text Available PT. Takagi Sari Multi Utama adalah perusahaan manufaktur yang bergerak di bidang injeksi plastik untuk produk otomotif terutama pada kendaraan bermotor. Karena begitu banyaknya pelanggan yang mempercayakan produk plastik injectionnya, maka PT. Takagi Sari Multi Utama harus memperhatikan mold yang digunakan sebagai sarana atau alat produksi memiliki kualitas yang tinggi. Karena begitu pentingnya suatu kualitas mold dan daya tahan mold terhadap penjaminan kualitas produksi, maka penulis mencari masalah utama yang terjadi PT. takagi Sari Multi Utama dengan menggunakan diagram pareto. Berdasarkan diagram terebut diperoleh data penyebap kerusakan mold paling tinggi adalah Design and Mold Structur dengan 154 Kejadian. Masalah Design and Mold Structur dipetakan dalam fishbone diagram untuk mengetahui permasalahan apa saja yang menyebapkan. Permasalahan yang ditemukan dilakukan analisa menggunakan FMEA (Failure Mode and Efect Analisis sebagai landasan melakukan perbaikan. Dengan metoda FMEA (Failure Mode and Efect Analisis diperoleh kesimpulan bahwa buruknya desain dan kontruksi mold dikarenakan tidak adanya standar desain yang digunakan sebagai acuhan proses desain dan pemeriksaan mold saat proses manufacturing dengan nilai RPN 567. Oleh karena itu proses perbaikan dilakukan dengan membuat standar desain mold di PT. Takagi Sari Multi Utama kemudian mencoba menerapkannya pada desain mold Cover Side 3/4.

  14. Optimization design of wide face water slots for medium-thick slab casting mold

    Directory of Open Access Journals (Sweden)

    Xue-lin Yin

    2016-09-01

    Full Text Available A three-dimensional finite-element model has been established to investigate the thermal behavior of the medium-thick slab copper casting mold with different cooling water slot designs. The mold wall temperatures measured using thermocouples buried in different positions of the mold with the original designed cooling system were analyzed to determine the corresponding heat flux profile. This profile was then used for simulation to predict the temperature distribution and the thermal stress distribution of the molds. The predicted temperatures during operation matched the plant measurements. The results showed that the maximum temperature, about 635 K in the wide hot surface, was found about 60 mm below the meniscus and 226 mm from the center of the mold. For the mold with the type I modified design, there was an insignificant decrease in temperature of about 5 K, and for the mold with the type II modified design, the maximum temperature was decreased by about 15 K and the temperature of the hot surface was distributed more uniformly along the length of the mold. The corresponding maximum thermal stress at the hot surface of the mold was reduced from 408 MPa to 386 MPa with the type II modified design. The results indicated that the modified design II is beneficial to the increase of mold life and the quality of casting slabs.

  15. Environmental mold and mycotoxin exposures elicit specific cytokine and chemokine responses.

    Directory of Open Access Journals (Sweden)

    Jamie H Rosenblum Lichtenstein

    Full Text Available Molds can cause respiratory symptoms and asthma. We sought to use isolated peripheral blood mononuclear cells (PBMCs to understand changes in cytokine and chemokine levels in response to mold and mycotoxin exposures and to link these levels with respiratory symptoms in humans. We did this by utilizing an ex vivo assay approach to differentiate mold-exposed patients and unexposed controls. While circulating plasma chemokine and cytokine levels from these two groups might be similar, we hypothesized that by challenging their isolated white blood cells with mold or mold extracts, we would see a differential chemokine and cytokine release.Peripheral blood mononuclear cells (PBMCs were isolated from blood from 33 patients with a history of mold exposures and from 17 controls. Cultured PBMCs were incubated with the most prominent Stachybotrys chartarum mycotoxin, satratoxin G, or with aqueous mold extract, ionomycin, or media, each with or without PMA. Additional PBMCs were exposed to spores of Aspergillus niger, Cladosporium herbarum and Penicillium chrysogenum. After 18 hours, cytokines and chemokines released into the culture medium were measured by multiplex assay. Clinical histories, physical examinations and pulmonary function tests were also conducted. After ex vivo PBMC exposures to molds or mycotoxins, the chemokine and cytokine profiles from patients with a history of mold exposure were significantly different from those of unexposed controls. In contrast, biomarker profiles from cells exposed to media alone showed no difference between the patients and controls.These findings demonstrate that chronic mold exposures induced changes in inflammatory and immune system responses to specific mold and mycotoxin challenges. These responses can differentiate mold-exposed patients from unexposed controls. This strategy may be a powerful approach to document immune system responsiveness to molds and other inflammation-inducing environmental agents.

  16. Control on Quality of Molding Sand in Static Pressure Molding Line%静压造型线型砂质量控制

    Institute of Scientific and Technical Information of China (English)

    李锦荣; 令军科; 王新智

    2011-01-01

    High quantities of addition of core sands to molding sand for multiple products production in our molding line has resulted in deteriorative molding sand and batch defect of metal penetration. After adjusting the addition of sand and mix process, stable properties of molding sand have been obtained and quality problems with molding sand and metal penetration of casting defect effectively resolved.%我公司静压造型线因生产品种多,芯砂流入量大,导致型砂性能恶化,铸件出现批量粘砂;通过调整型砂配比及混制工艺,稳定了型砂性能,有效解决了型砂质量问题和铸件粘砂缺陷.

  17. Identification of bacterias from the slime and the study on their bioflim activity%腐浆中细菌的鉴定及其生物膜活性研究

    Institute of Scientific and Technical Information of China (English)

    焦虎美; 时留新

    2012-01-01

    纸机运转过程中的腐浆障碍主要是由系统内微生物所引起的.从UPM常熟纸厂PM2纸机机架的腐浆里筛选得到10株细菌N1、N2……N10,通过对其形态特征、生理生化特性以及16SrRNA序列分析,初步鉴定N1、N3为鞘氨醇单孢菌(Sphingomonas azotifigens)、N2为腐败假单孢菌(Pseudomonas putrefaciens)、N4为未培养细菌(uncultured bacterium)、N5为Filimonas lacunae、N6为Asticcacaulis excentricus、N7为少动假单孢菌(Pseudomonas paucimobilis)、N8为Siphonobacter aquaeclarae、N9为不解糖鞘氨醇单孢菌(Sphingomonas pruni)、N10为Flectobacillus Larkin.将分离后的10株细菌分别回接到含细小纤维的回接试样中,检测腐浆细菌的生物膜对细小纤维的絮聚情况,结果显示N5、N8、N10对细小纤维有很大的絮凝沉淀作用,由此推断这3株细菌的生物膜活性强,是腐浆中的有害细菌.%The slime pulp, causing much trouble for the pulp and paper making industry, is usually produced by bacterium. Ten kinds of bacteria including N1, N2, ..., N10 were screened from the slime hanging on the PM2 paper machine at UPM. They were identified as Sphingomonas azotifigens( Nl , N3) , Pseudomonas putrefaciens( N2 ) , uncultured bacterium ( N4) , FUimonas lacunae ( N5 ) , Asticcacaulis excentricus( N6) , Pseudomonas paucimobilis ( N7) , Siphonobacter aquaedarae ( N8 ) , Sphingomonas pruni ( N9) , Fkctobacillus Lark in (N10) through the morphological observation, physiological & chemical tests and 16S rRNA sequence analysis. Inoculate these bacteria to the simulative white water system and detect whether the slime was produced. It was proved that N5,N8,N10 were the key bacteria for the slime.

  18. Methods of Automatic Parting Mold and Manual Parting Mold for Injection Mold Design Based on UG%基于UG注射模设计的自动分模和手动分模方法

    Institute of Scientific and Technical Information of China (English)

    董海涛

    2012-01-01

    UG software is widely applied in plastic injection mold design,the basic principle of parting mold is introduced in this paper,and the UG application in plastic injection mold design is studied with a concrete case.The process of automatic parting mold and manual parting mold in UG are expatiated,the flexible application of two methods will significantly reduce mold design time and greatly improve the efficiency of injection mold design.%UG软件广泛地应用在注射模设计中,本文介绍了分模原理,并结合实例研究UG软件在注射模设计中的应用。介绍了自动分模和手动分模方法,两种方法的灵活应用可以缩短模具设计周期,提高注射模设计的效率。

  19. Molecular and Cellular Signaling

    CERN Document Server

    Beckerman, Martin

    2005-01-01

    A small number of signaling pathways, no more than a dozen or so, form a control layer that is responsible for all signaling in and between cells of the human body. The signaling proteins belonging to the control layer determine what kinds of cells are made during development and how they function during adult life. Malfunctions in the proteins belonging to the control layer are responsible for a host of human diseases ranging from neurological disorders to cancers. Most drugs target components in the control layer, and difficulties in drug design are intimately related to the architecture of the control layer. Molecular and Cellular Signaling provides an introduction to molecular and cellular signaling in biological systems with an emphasis on the underlying physical principles. The text is aimed at upper-level undergraduates, graduate students and individuals in medicine and pharmacology interested in broadening their understanding of how cells regulate and coordinate their core activities and how diseases ...

  20. A Review of Mold Flux Development for the Casting of High-Al Steels

    Science.gov (United States)

    Wang, Wanlin; Lu, Boxun; Xiao, Dan

    2016-02-01

    Mold flux plays key roles during the continuous casting process of molten steel, which accounts for the quality of final slabs. With the development of advanced high strength steels (AHSS), certain amounts of Al have been added into steels that would introduce severe slag/metal interaction problems during process of continuous casting. The reaction is between Al and SiO2 that is the major component in the mold flux system. Intensive efforts have been conducted to optimize the mold flux and a CaO-Al2O3-based mold flux system has been proposed, which shows the potential to be applied for the casting process of AHSS. The latest developments for this new mold flux system were summarized with the aim to offer technical guidance for the design of new generation mold flux system for the casting of AHSS.

  1. A model for mold collaborative manufacturing execution system based on Web Service

    Institute of Scientific and Technical Information of China (English)

    Zhao Lizhong; Wang Yanbin; Gao Guoan

    2006-01-01

    Mold manufacturing Extended Enterprise (EE) has the following characteristics: distributed in locality, tight cooperation and frequent information exchange. It needs a collaborative, highly efficient, reliable and intelligent manufacturing management system. The background of the Collaborative Manufacturing is introduced. A mold Collaborative Manufacturing Execution System (c-MES) is proposed. The feature of Web Service platform is analyzed. The necessity and feasibility of importing the Web Service to mold c-MES are discussed. Based on Web Service, the model of mold c-MES is built. Every module's function is described in detail, including the functions it supplies and the mechanism of information interaction among them. The feasibility of mold c-MES model is validated by a real mold manufacturing case.

  2. Analysis of Cavity Pressure and Warpage of Polyoxymethylene Thin Walled Injection Molded Parts: Experiments and Simulations

    DEFF Research Database (Denmark)

    Guerrier, Patrick; Tosello, Guido; Hattel, Jesper Henri

    2014-01-01

    , melt and mold temperatures, material rheological and pvT characterization. Factors investigated for comparisons were: injection pressure profile, short shots length, flow pattern, and warpage. A reliable molding experimental database was obtained, accurate simulations were conducted and a number......Process analysis and simulations on molding experiments of 3D thin shell parts have been conducted. Moldings were carried out with polyoxymethylene (POM). The moldings were performed with cavity pressure sensors in order to compare experimental process results with simulations. The warpage...... was characterized by measuring distances using a tactile coordinate measuring machine (CMM). Molding simulations have been executed taking into account actual processing conditions. Various aspects have been considered in the simulation: machine barrel geometry, injection speed profiles, cavity injection pressure...

  3. Geographic Distribution of Environmental Relative Moldiness Index Molds in USA Homes

    Directory of Open Access Journals (Sweden)

    Stephen Vesper

    2011-01-01

    Full Text Available Objective. The objective of this study was to quantify and describe the distribution of the 36 molds that make up the Environmental Relative Moldiness Index (ERMI. Materials and Methods. As part of the 2006 American Healthy Homes Survey, settled dust samples were analyzed by mold-specific quantitative PCR (MSQPCR for the 36 ERMI molds. Each species' geographical distribution pattern was examined individually, followed by partitioning analysis in order to identify spatially meaningful patterns. For mapping, the 36 mold populations were divided into disjoint clusters on the basis of their standardized concentrations, and First Principal Component (FPC scores were computed. Results and Conclusions. The partitioning analyses failed to uncover a valid partitioning that yielded compact, well-separated partitions with systematic spatial distributions, either on global or local criteria. Disjoint variable clustering resulted in seven mold clusters. The 36 molds and ERMI values themselves were found to be heterogeneously distributed across the United States of America (USA.

  4. Study on Type C Coal Fly ash as an Additive to Molding Sand for Steel Casting

    Science.gov (United States)

    Palaniappan, Jayanthi

    2017-04-01

    Study of physio-chemical properties studies such as granulometric analysis, moisture, X ray fluorescence etc. were performed with Type C coal—combustion fly ash to investigate their potential as a distinct option for molding sand in foundry, thereby reducing the dependency on latter. Technological properties study such as compressive strength, tensile strength, permeability and compaction of various compositions of fly ash molding sand (10, 20 and 30 % fly ash substitute to chemically bonded sand) were performed and compared with silica molding sand. Steel casting production using this fly ash molding sand was done and the casting surface finish and typical casting parameters were assessed. It was noted that a good quality steel casting could be produced using type C fly ash molding sand, which effectively replaced 20 % of traditional molding sand and binders thereby providing greater financial profits to the foundry and an effective way of fly ash utilization (waste management).

  5. Analysis of emissions collected from four types of iron casting molds.

    Science.gov (United States)

    Palmer, W G; James, R H; Moorman, W J

    1985-12-01

    The levels of polycyclic aromatic hydrocarbons (PAH) and related compounds, phenols and particulates were determined in emissions collected from iron casting molds composed of four different types of chemical binders: furan, urethane, green sand with sea coal and phenol-formaldehyde resins in shell molds. The shell sample, with 50% particulates, contained the most water-soluble material; green sand, 25% particulates; furan, 10% particulates; and urethane, less than 2% particulate material. The portion of the particulate fraction soluble in cyclohexane varies from 16 to 36% between mold types; emissions from urethane and furan molds contained the lowest quantities of cyclohexane-soluble components and of PAH and related compounds. Phenol, which was found in all four foundry samples, was present in the highest concentration in emissions from urethane molds. Shell mold emissions contained the highest levels of 2- and 4-nitrophenol.

  6. Differentiation of Toxic Molds via Headspace SPME-GC/MS and Canine Detection

    Directory of Open Access Journals (Sweden)

    Kenneth G. Furton

    2007-08-01

    Full Text Available Indoor mold growth has recently become a concern in the legal world in regards to insurance litigation. Hazardous mold exposure to humans has been linked to many acute and chronic adverse health effects including death. As it grows, mold produces several types of primary and secondary metabolites, including microbial volatile organic compounds (MVOCs. Microbial volatile organic compound emission may be used as a preliminary indication of a mold infestation that is invisible to the unaided eye. The objective of the study is to identify the unique odor signatures of three species of molds, Aspergillus versicolor, Penicillium chrysogenum, and Stachybotrys chartarum by SPME-GC/MS analysis. Determining the compounds that are emitted by the selected species has made it possible to conduct validation studies of canine detection of these mold species through a series of field tests.

  7. Environment Aware Cellular Networks

    KAUST Repository

    Ghazzai, Hakim

    2015-02-01

    The unprecedented rise of mobile user demand over the years have led to an enormous growth of the energy consumption of wireless networks as well as the greenhouse gas emissions which are estimated currently to be around 70 million tons per year. This significant growth of energy consumption impels network companies to pay huge bills which represent around half of their operating expenditures. Therefore, many service providers, including mobile operators, are looking for new and modern green solutions to help reduce their expenses as well as the level of their CO2 emissions. Base stations are the most power greedy element in cellular networks: they drain around 80% of the total network energy consumption even during low traffic periods. Thus, there is a growing need to develop more energy-efficient techniques to enhance the green performance of future 4G/5G cellular networks. Due to the problem of traffic load fluctuations in cellular networks during different periods of the day and between different areas (shopping or business districts and residential areas), the base station sleeping strategy has been one of the main popular research topics in green communications. In this presentation, we present several practical green techniques that provide significant gains for mobile operators. Indeed, combined with the base station sleeping strategy, these techniques achieve not only a minimization of the fossil fuel consumption but also an enhancement of mobile operator profits. We start with an optimized cell planning method that considers varying spatial and temporal user densities. We then use the optimal transport theory in order to define the cell boundaries such that the network total transmit power is reduced. Afterwards, we exploit the features of the modern electrical grid, the smart grid, as a new tool of power management for cellular networks and we optimize the energy procurement from multiple energy retailers characterized by different prices and pollutant

  8. Numerical modeling of magnetic induction and heating in injection molding tools

    DEFF Research Database (Denmark)

    Guerrier, Patrick; Hattel, Jesper Henri

    2013-01-01

    Injection molding of parts with special requirements or features such as micro- or nanostructures on the surface, a good surface finish, or long and thin features results in the need of a specialized technique to ensure proper filling and acceptable cycle time. The aim of this study is to increase...... numerical modeling of the induction heating in the mold to investigate how the temperature in the mold will be distributed and how it is affected by different material properties....

  9. Cure Cycle Effect on High-Temperature Polymer Composite Structures Molded by VARTM

    OpenAIRE

    Ahmed Khattab

    2013-01-01

    This paper presents an analytical and experimental investigation of cure cycle effect on carbon-fiber reinforced high-temperature polymer composite structures molded by vacuum assisted resin transfer molding (VARTM). The molded composite structure consists of AS4-8 harness carbon-fiber fabrics and a high-temperature polymer (Cycom 5250-4-RTM). Thermal and resin cure analysis is performed to model the cure cycle of the VARTM process. The temperature and cure variations with time are determined...

  10. Improving Cooling Rate During Solidification by Eliminating the Metal-Mold Interfacial Gap

    Science.gov (United States)

    Zeng, Long; Zhang, Wei; Ji, Yanliang; Huang, Yujin; Li, Jianguo

    2015-07-01

    A new solidification process called non-interfacial-gap permanent-mold casting (NIGPMC) is proposed to improve the cooling rate by eliminating the metal-mold interfacial gap. High-Cr steel ingots were prepared by this process and conventional permanent-mold casing (CPMC) separately. Comparing with CPMC, the primary dendrite arm spacing obtained by NIGPMC is greatly refined. It is demonstrated that the NIGPMC is a promising pathway to refine the microstructure of the large ingot.

  11. Vacuum Infusion Molding Process Part 1:VIMP Based on a High-Permeable Medium

    Institute of Scientific and Technical Information of China (English)

    ZHU Ying-dan; WANG Ji-hui; YANG Zui; TAN Hua

    2003-01-01

    The visualization experiments were carried out to investigate the permeability of the high-permeable medium (HPM) and the roles of the peel ply and the HPM in the mold filling.The influence of process parameters on mold filling is discussed.Furthermore,the whole vacuum infusion molding process (VIMP) procedure is introduced in detail taking the manufacture of a model boat for example.

  12. Preparation of liquefied wood-based resins and their application in molding material

    Institute of Scientific and Technical Information of China (English)

    Zhang Qiu-hui; Zhao Guang-jie; Yu Li-li; Jie Shu-jun

    2007-01-01

    To investigate value in use of liquefied wood-based resin applications in molding material, Chinese fir (Cunninghamia lanceolata) and poplar (Populus tomentosa) wood meal were liquefied in phenol. The reactant was co-condensed with formaldehyde to obtain liquefied wood-based resin. For this paper, we investigated the characterization of the resin and its application in molding material. The result shows that the basic properties of liquefied wood-based resin were satisfactory; the bonding strength of plywood prepared with liquefied Chinese fir and liquefied poplar resin can reach 1.54 and 1.00 MPa, respectively. The compression strengths of the molding material prepared with two kinds of liquefied wood resin were 73.01 and 73.58 MPa, almost the same as that of PF resin molding material. The limiting volume swelling of molding material made with liquefied Chinese resin and liquefied poplar resin were 8.5% and 8.3%, thickness swelling rates of water absorption were 3.3% and 4.2%, and the maximum weight ratios of water absorption were 25.9% and 26.2%, respectively. The soil burial test result shows that the weight loss rate of the molding materials made with liquefied Chinese resin and liquefied poplar resin were 8.3% and 9.1% and that of the PF resin molding material was 7.9%. After the soil internment test, the reduction ratio of compression strength of the two kinds of molding material achieved 16.9%and 17.7%, while that of the PF resin molding material was 15.4%. The test results of wood fungi inoculation on the three surfaces of the molding material indicate the breeding rate of molding material prepared with liquefied Chinese resin and liquefied poplar resin were at level 4 and that of PF resin molding material was at level 1 of the ISO standard.

  13. IMPROVEMENT OF EQUIPMENT FOR EFFECTIVE HARDENING SAND MIXTURE BY VACUUM MOLDING

    Directory of Open Access Journals (Sweden)

    V. S. Doroshenko

    2016-01-01

    Full Text Available The review deals with the design flask tooling and patterns for effective hardening sand mixture in the vacuum molding (V-Process, and molding on a one-off patterns (Lost Foam Casting. Sealing and evacuating sand mixture – two major factors influence the strength of the casting mold and casting quality, management practices which will enable to improve the casting process.

  14. Injection molded polymer chip for electrochemical and electrophysiological recordings from single cells

    DEFF Research Database (Denmark)

    Tanzi, Simone; Larsen, Simon Tylsgaard; Taboryski, Rafael J.

    We present a novel method to fabricate an all in polymer injection molded chip for electrochemical cell recordings and lateral cell trapping. The complete device is molded in thermoplastic polymer and it results from assembling two halves. We tested spin-coated conductive polymer poly(3,4-ethylen......We present a novel method to fabricate an all in polymer injection molded chip for electrochemical cell recordings and lateral cell trapping. The complete device is molded in thermoplastic polymer and it results from assembling two halves. We tested spin-coated conductive polymer poly(3...

  15. Gate Design in Injection Molding of Microfluidic Components Using Process Simulations

    DEFF Research Database (Denmark)

    Marhöfer, David Maximilian; Tosello, Guido; Islam, Aminul

    2016-01-01

    Just as in conventional injection molding of plastics, process simulationsare an effective and interesting tool in the area of microinjection molding. They can be applied in order to optimize and assist the design of the microplastic part, the mold, and the actual process. Available simulation...... software is however actually made for macroscopic injection molding. By means of the correct implementation and careful modeling strategy though, it can also be applied to microplastic parts, as it is shown in the present work. Process simulations were applied to two microfluidic devices (amicrofluidic...

  16. The Relationship between Mold Exposure and Allergic Response in Post-Katrina New Orleans

    Directory of Open Access Journals (Sweden)

    Felicia A. Rabito

    2010-01-01

    Full Text Available Objectives. The study's objective was to examine the relation between mold/dampness exposure and mold sensitization among residents of Greater New Orleans following Hurricane Katrina. Methods. Patients were recruited from the Allergy Clinic of a major medical facility. Any patient receiving a skin prick test for one of 24 molds between December 1, 2005 and December 31, 2008 was eligible for the study. Exposure was assessed using standardized questionnaires. Positive mold reactivity was defined as a wheal diameter >3 mm to any mold genera. Results. Approximately 57% of participants tested positive to any indoor allergen, 10% to any mold. Over half of respondents had significant home damage, 34% reported dampness/mold in their home, half engaged in renovation, and one-third lived in a home undergoing renovation. Despite extensive exposure, and multiple measures of exposure, we found no relationship between mold/dampness exposure and sensitivity to mold allergens. Conclusions. These results along with results of earlier research indicate no excess risk of adverse respiratory effects for residents living in New Orleans after the devastation of Hurricane Katrina.

  17. Gate design in injection molding of microfluidic components using process simulations

    DEFF Research Database (Denmark)

    Marhöfer, D. M.; Tosello, G.; Islam, A.;

    2015-01-01

    Just as in conventional injection molding of plastics, process simulations are an effective tool in the area of micro injection molding. They are applied in order to optimize and aid the design of the micro plastic part, the mold and the actual process. Available simulation software is actually...... made for macroscopic injection molding, but by means of the correct implementation and modelling strategy it can also be applied to micro plastic parts, as it is shown in the presented work. Process simulations are applied to two microfluidic devices (a micro distributor and a micro mixer) which shall...

  18. Atomic layer deposition as pore diameter adjustment tool for nanoporous aluminum oxide injection molding masks.

    Science.gov (United States)

    Miikkulainen, Ville; Rasilainen, Tiina; Puukilainen, Esa; Suvanto, Mika; Pakkanen, Tapani A

    2008-05-06

    The wetting properties of polypropylene (PP) surfaces were modified by adjusting the dimensions of the surface nanostructure. The nanostructures were generated by injection molding with nanoporous anodized aluminum oxide (AAO) as the mold insert. Atomic layer deposition (ALD) of molybdenum nitride film was used to control the pore diameters of the AAO inserts. The original 50-nm pore diameter of AAO was adjusted by depositing films of thickness 5, 10, and 15 nm on AAO. Bis(tert-butylimido)-bis(dimethylamido)molybdenum and ammonia were used as precursors in deposition. The resulting pore diameters in the nitride-coated AAO inserts were 40, 30, and 20 nm, respectively. Injection molding of PP was conducted with the coated inserts, as well as with the non-coated insert. Besides the pore diameter, the injection mold temperature was varied with temperatures of 50, 70, and 90 degrees C tested. Water contact angles of PP casts were measured and compared with theoretical contact angles calculated from Wenzel and Cassie-Baxter theories. The highest contact angle, 140 degrees , was observed for PP molded with the AAO mold insert with 30-nm pore diameter. The Cassie-Baxter theory showed better fit than the Wenzel theory to the experimental values. With the optimal AAO mask, the nanofeatures in the molded PP pieces were 100 nm high. In explanation of this finding, it is suggested that some sticking and stretching of the nanofeatures occurs during the molding. Increase in the mold temperature increased the contact angle.

  19. Micro powder injection molding-large scale production technology for micro-sized components

    Institute of Scientific and Technical Information of China (English)

    YIN HaiQing; JIA ChengChang; QU XuanHui

    2008-01-01

    Micro powder injection molding (μPIM), a miniaturized variant of powder injection molding, has advantages of shape complexity, applicability to many materials and good mechanical properties. Co-injection molding has been realized between metals and ceramics on micro components, which become the first breakthrough within the PIM field. Combined with the prominent characteristics of high features/cost ratio, micro powder injection molding becomes a potential technique for large scale production of intricate and three-dimensional micro components or microstructured components in microsystems technology (MST) field.

  20. Nanopatterning planar and non-planar mold surfaces for a polymer replication

    DEFF Research Database (Denmark)

    Cech, Jiri; Pranov, Henrik; Kofod, Guggi;

    2013-01-01

    , freestanding nickel foil with a reversed pattern. This foil is then used either as a direct master for polymer replication or as a master for an extremely high pressure embossing of such master onto a metallic injection mold cavity surface coated with special coating, which, when cured, forms robust and hard......, glass-like material. We have demonstrated nanopattern transfer on both planar and non-planar geometries and our nanopatterned mold coating can sustain more than 10.000 injection molding cycles. We can coat our nanopatterned mold surfaces with a monolayer of perfluorosilane to further reduce surface...

  1. Experimental method for determination of a suitable temperature range for glasses used in precision molding

    Science.gov (United States)

    Ma, Tao; Chen, Fan; Yu, Jingchi

    2010-10-01

    Viscosity of glass is one of its important technological properties. It is usually adopted as a mark in controlling and evaluating the workability of glass. The viscous features in a glass forming process are strongly relevant to the temperature distribution. Appropriate procedure setting and controlling of temperature is an essential issue for precision glass molding. But the characteristic viscosity of glass is difficult to be observed directly in a practical lens molding. It's not convenient to set up the molding conditions caused by the differences between theoretical data and actual system. The purpose of this experimental study is intended to provide a simple and reliable method for determination of suitable temperature intervals of glasses used in the precision molding fabrication which meets the requirements of process tolerances in the industrial productions. The average glass deforming force and center thickness of molded lens are taken as the two conditions of determination principle for molding temperature ranges. The average force should not less than the minimum value of measurement accuracy and the lens thickness should reach the design target in these temperature ranges. These two conditions are easy to be measured and fit for application in the engineering. The molding temperature ranges of several kinds of glass were obtained in this project. One of them is Schott optical glass P-LASF51 which is selected for evaluating and validating this method. Its suitable molding temperature range is from 590 to 614 . The results of molding experiments demonstrate the method is effective and feasible.

  2. The Development of a Ceramic Mold for Hot-Forging of Micro-Magnets

    Energy Technology Data Exchange (ETDEWEB)

    Christenson, Todd; Garino, Terry

    1999-06-25

    A new mold material has been developed for use in making rare-earth permanent magnet components with precise dimensions in the 10 to 1000 µm range by hot-forging. These molds are made from molds poly(methyl)methacrylate (PMMA) made by deep x-ray lithography (DXRL). An alumina bonded with colloidal silica has been developed for use in these molds. This material can be heated to 950°C without changing dimensions where it develops the strength needed to withstand the hot-fmging conditions (750°C, 100 MPa). In addition, it disintegrates in HF so that parts can be easily removed after forging.

  3. Nasal Outcomes of Presurgical Nasal Molding in Complete Unilateral Cleft Lip and Palate

    Directory of Open Access Journals (Sweden)

    Emily M. Williams

    2012-01-01

    Full Text Available Objective. Short-term nasal forms following primary lip repair were compared between presurgical nasal molding and control groups. Aim. To compare nasal symmetry between patients that had nasal molding and lip repair with those that had only lip repair. Design. Retrospective case-control study Patients. Complete unilateral CL+P patients had basilar and frontal photographs at two time points: (1 initial (2 postsurgical. 28 nasal molding patients and 14 control patients were included. Intervention. Presurgical nasal molding was performed prior to primary lip repair in intervention group. No nasal molding was performed in control group. Hypothesis. Nasal molding combined with lip surgery repair according to the Millard procedure provides superior nasal symmetry than surgery alone for nostril height-width ratios and alar groove ratios. Statistics. Shapiro-Wilk test of normality and Student’s -tests. Results. A statistically significant difference was found for postsurgical nostril height-width ratio (<.05. No other statistically significant differences were found. Conclusions. Nasal molding and surgery resulted in more symmetrical nostril height-width ratios than surgery alone. Alar groove ratios were not statistically significantly different between groups perhaps because application of nasal molding was not early enough; postsurgical nasal splints were not utilized; overcorrection was not performed for nasal molding.

  4. Characterization of Microstructure of Permanent Mold Cast Zinc Alloy ZA27

    Institute of Scientific and Technical Information of China (English)

    CHEN Ti-jun; LI Yuan-dong; HAO Yuan

    2004-01-01

    The microstructure of permanent mold cast zinc alloy ZA27 was examined by SEM and TEM after natural aging for 18 months. It was found that the primary α' phase, peritectic and eutectic β phases all decomposed into the equilibrium well-formed α+η lamellae or irregular α+η structure through cellular reaction. The cell colonies nucleated on the interdendritic eutectic η layer and grew into the primary dendrites, thus first making the β phase in the dendrite edges decompose, and then the α' phase in the dendrite cores. The products from the α' phase appeared in regular lamellae rather than irregular particles. In addition, a fine, dense transitional phase α'm containing 27.8 mass% Al, with a fcc crystal structure and lattice parameter of about 0.4013nm, formed in α lamellae. Copper was preferentially concentrated in Zn-rich η phase and existed in the form of Cu-rich ε phase (CuZr4) particles, with hcp crystal structure and parameters a=0.274nm,c=0.429nm and c/a=1.567.

  5. Solidification Structure of Continuous Casting Large Round Billets under Mold Electromagnetic Stirring

    Institute of Scientific and Technical Information of China (English)

    Tao SUN; Feng YUE; Hua-jie WU; Chun GUO; Ying LI; Zhong-cun MA

    2016-01-01

    The solidification structure of a continuous casting large round billet was analyzed by a cellular-automaton-finite-element coupling model using the ProCAST software.The actual and simulated solidification structures were compared under mold electromagnetic stirring (MEMS)conditions (current of 300 A and frequency of 3 Hz).There-after,the solidification structures of the large round billet were investigated under different superheats,casting speeds,and secondary cooling intensities.Finally,the effect of the MEMS current on the solidification structures was obtained under fixed superheat,casting speed,secondary cooling intensity,and MEMS frequency.The model accurately simulated the actual solidification structures of any steel,regardless of its size and the parameters used in the continuous casting process.The ratio of the central equiaxed grain zone was found to increase with decreasing su-perheat,increasing casting speed,decreasing secondary cooling intensity,and increasing MEMS current.The grain size obviously decreased with decreasing superheat and increasing MEMS current but was less sensitive to the casting speed and secondary cooling intensity.

  6. Nanoindentation Analysis for Mechanical Properties of Electroless NiP Imprinting Mold Replicated from Self-Assembled-Monolayer Modified Master Mold

    Science.gov (United States)

    Lin, Cheng Ping; Saito, Mikiko; Homma, Takayuki

    2013-11-01

    A NiP imprinting mold with patterns, whose size is from nanometer to submicrometer (170, 500, and 1000 nm diameter), was fabricated by electroless deposition of NiP on a 3-aminopropyltriethoxysilane (APTES) modified master mold. The NiP deposit as a replicate mold was then detached from the master mold. The initial NiP deposition in patterns of the master mold was investigated; moreover, nanoindentation was successfully performed on a single NiP pattern for investigating the hardness. The NiP had a similar grain size in different sizes of patterns of the master mold during the initial deposition, as well as the same hardness of the NiP patterns (approximately 12 GPa) was observed. These results indicated that the initial NiP deposition and hardness of NiP were not size dependent above 170 nm. The surface morphology of the NiP detached from the master mold and NiP pattern of different sizes were investigated as well.

  7. Cellular communication through light.

    Directory of Open Access Journals (Sweden)

    Daniel Fels

    Full Text Available Information transfer is a fundamental of life. A few studies have reported that cells use photons (from an endogenous source as information carriers. This study finds that cells can have an influence on other cells even when separated with a glass barrier, thereby disabling molecule diffusion through the cell-containing medium. As there is still very little known about the potential of photons for intercellular communication this study is designed to test for non-molecule-based triggering of two fundamental properties of life: cell division and energy uptake. The study was performed with a cellular organism, the ciliate Paramecium caudatum. Mutual exposure of cell populations occurred under conditions of darkness and separation with cuvettes (vials allowing photon but not molecule transfer. The cell populations were separated either with glass allowing photon transmission from 340 nm to longer waves, or quartz being transmittable from 150 nm, i.e. from UV-light to longer waves. Even through glass, the cells affected cell division and energy uptake in neighboring cell populations. Depending on the cuvette material and the number of cells involved, these effects were positive or negative. Also, while paired populations with lower growth rates grew uncorrelated, growth of the better growing populations was correlated. As there were significant differences when separating the populations with glass or quartz, it is suggested that the cell populations use two (or more frequencies for cellular information transfer, which influences at least energy uptake, cell division rate and growth correlation. Altogether the study strongly supports a cellular communication system, which is different from a molecule-receptor-based system and hints that photon-triggering is a fine tuning principle in cell chemistry.

  8. 潘一选煤厂在煤泥泥化条件下的浮选操作实践%Practice on Flotation Operation under the Condition of Slime Argillization in Panyi Coal Preparation Plant

    Institute of Scientific and Technical Information of China (English)

    王传志

    2014-01-01

    In order to solve the problem of the quality of flotation product due to selected raw coal slime argilliza-tion in Panyi Coal Preparation Plant ,combined with the characteristics of flotation technique process ,the condi-tion of best flotation operation has been determined by orthogonal test ,which exerted sufficiently the reducing dust of desliming pit and second flotation ,effectively reduced the influence of slime argillization on flotation and ensured the quality of flotation product .%为解决潘一选煤厂因入选原煤煤泥泥化严重而影响浮选产品质量的问题,结合浮选工艺流程特点,通过正交试验确定了浮选最佳操作条件,充分发挥脱泥池、二次浮选的降灰作用,有效地降低了煤泥泥化对浮选的影响,保证了浮选产品质量。

  9. Cellular automata: structures

    OpenAIRE

    Ollinger, Nicolas

    2002-01-01

    Jury : François Blanchard (Rapporteur), Marianne Delorme (Directeur), Jarkko Kari (Président), Jacques Mazoyer (Directeur), Dominique Perrin, Géraud Sénizergues (Rapporteur); Cellular automata provide a uniform framework to study an important problem of "complex systems" theory: how and why do system with a easily understandable -- local -- microscopic behavior can generate a more complicated -- global -- macroscopic behavior? Since its introduction in the 40s, a lot of work has been done to ...

  10. Engineering Cellular Metabolism

    DEFF Research Database (Denmark)

    Nielsen, Jens; Keasling, Jay

    2016-01-01

    Metabolic engineering is the science of rewiring the metabolism of cells to enhance production of native metabolites or to endow cells with the ability to produce new products. The potential applications of such efforts are wide ranging, including the generation of fuels, chemicals, foods, feeds...... of metabolic engineering and will discuss how new technologies can enable metabolic engineering to be scaled up to the industrial level, either by cutting off the lines of control for endogenous metabolism or by infiltrating the system with disruptive, heterologous pathways that overcome cellular regulation....

  11. Failover in cellular automata

    CERN Document Server

    Kumar, Shailesh

    2010-01-01

    A cellular automata (CA) configuration is constructed that exhibits emergent failover. The configuration is based on standard Game of Life rules. Gliders and glider-guns form the core messaging structure in the configuration. The blinker is represented as the basic computational unit, and it is shown how it can be recreated in case of a failure. Stateless failover using primary-backup mechanism is demonstrated. The details of the CA components used in the configuration and its working are described, and a simulation of the complete configuration is also presented.

  12. Leaching process of anode slime with high silver and bismuth%高银铋阳极泥浸出工艺研究

    Institute of Scientific and Technical Information of China (English)

    何静; 郭瑞; 蓝明艳; 王灿; 鲁君乐

    2013-01-01

      某厂高银铋阳极泥产粗铋及综合回收有价金属,工艺采用两段浸出法处理此阳极泥,第1段硫酸浸出铜,第2段盐酸浸出铋.分别考察了浸出温度、时间、液固比(质量比)、酸量及氧化剂用量对浸出率的影响.铜的浸出率(液计)96%以上,铋、锑的浸出率(渣计)均在99%以上,铅、银富集于第2段浸出渣中,铅、银渣含Pb 26.63%左右,含Ag 36.77%左右,铅和银的直收率高,分别为97.82%及98.93%.浸出过程为串级联动循环浸出,洗酸洗水均返回下一次浸出,大大地减少了废水量,环境友好.%In order to produce crude bismuth and comprehensively recovery of valuable metals from anode slime with high silver and bismuth ,The process is Two-stage leaching. The first stage is leaching of copper with sulfuric acid and the second stage is leaching of bismuth with hydrochloric acid. Studied on the relationship between the Leaching rate and the leaching temperature, time, ratio of liquid to solid(Quality), dosage of acid and oxidant.The leaching rate (Liquid) of copper is above 96%,and The leaching rate (Slag) of bismuth and antimony are all above 99 %.The lead and silver are enriched in the second stage leaching slag, which containing Pb about 26.63%,Ag about 36.77 %,the direct yield of Pb and Ag are 97.82 % and 98.93 %respectively.The process is cycle leaching, washing water and washing acid are returned to the next leaching, which greatly reduced the amount of wastewater, and good for environmental protection.

  13. Aerobiological study of pollen and mold in Seoul, Korea

    Directory of Open Access Journals (Sweden)

    Jae-Won Oh

    1998-01-01

    Full Text Available In a large number of allergic individuals, inhalant allergens are important causative and triggering agents in respiratory allergies. It is essential to survey the pollen and mold around the patient’s environment for the diagnosis and treatment of airborne allergy. Rotorod samplers were installed at well-ventilated places in seven collecting stations in Seoul, the capital of Korea, which has a population of 12 million. Airborne particles carrying allergens were collected daily from each station for 2 years (1 October 1995 to 30 September 1997. After being stained with Calberla’s fuchsin, they were identified, counted and recorded. The weather in Seoul was also recorded. Pollen was found from the middle of February through to the end of December. The peak date for pollen was 12 May (peak mean daily count: 701 grains/m3/day and for mold it was 23 June (peak mean daily count: 936 spores/m3/day. Alder, birch, pine, oak, maple, elm, juniper, willow, and gingko trees were prevalent during the tree season, lasting from the middle of February to late July. Then sagebrush, ragweed, Japanese hop, and pigweed followed during the weed season, which lasts from the middle of July to the end of December. In skin prick test results, house dust mite was the most common positive allergen in Seoul, followed by cockroach. Among the pollens, mugwort was the most common positive, followed by ragweed mix, alder, birch, and grasses mix. Among the molds, there were high counts of Cladosporium and Alternaria during the year, excluding January. Ascospore of Lepto-spheria was highest during the monsoon season.

  14. Finite Element Analysis of Reciprocating Screw for Injection Molding Machine

    Directory of Open Access Journals (Sweden)

    Nagsen B. Nagrale

    2011-06-01

    Full Text Available This paper deals with, the solution of problem occurred for reciprocating screw of Injection molding machine. It identifies and solves the problem by using the modeling and simulation techniques. The problem occurred in the reciprocating screw of machine which was wearing of threads due to affect of temperature of mold materials(flow materials i.e. Nylon, low density polypropylene, polystyrene, PVC etc., The main work was to model the components of machine with dimensions, assemble those components and then simulate the whole assembly for rotation of the screw. The modeling software used is PRO-E wildfire 4.0 for modeling the machine components like body, movable platen, fixed platen, barrel, screw, nozzle, etc. The analysis software ANSYS is used to analyze the reciprocating screws. The objectives involved are:- • To model all the components using modeling software Pro-E 4.0 • To assemble all the components of the machine in the software. • To make the assembly run in Pro-E software.• Analysis of screw of machine using Ansys 11.0 software. • To identify the wearing of threads and to provide the possible solutions.This problem is major for all industrial injection molding machines which the industries are facing and they need the permanent solution, so if the better solution is achieved then the industries will think for implementing it. The industries are having temporary solution but it will affect the life of the screw, because the stresses will be more in machined screw on lathe machine as compared to normal screw. Also if the screw will fail after some years of operation, the new screw available in the market will have the same problem. Also the cost associated with new screw and its mounting is much more as it is the main component of machine.

  15. Composite manufacturing: Simulation of 3-D resin transfer molding

    Science.gov (United States)

    Tan, Cheng Ping

    1998-10-01

    A technique was developed for simulating the resin transfer molding (RTM) process. The major feature of the technique is a computational steering system that enables the user to make changes during the simulation. Specifically, at any instance, the user can inspect the progress of the resin front. On the basis of the observed resin front position, the user can, as needed, change the port and vent locations, open and close ports and vents, adjust the inlet and exit pressures or flow rates, and reorient the mold with respect to the gravitational field. Additionally, the user can "rewind" the simulator to any previous time in the mold filling process, make any of the above changes and then continue the simulation. The technique is augmented by a computer code which has three main components, the Simulator, the Graphics User Interface (GUI), and the Global Data Storage. The Simulator is a finite element code that calculates the resin flow inside the fiber preform. The GUI serves as the interface between the user and the Simulator; it provides the commands to the Simulator and displays the results. The Global Data Storage is the module that manages the exchange of data between the GUI and the Simulator. The computer code (designated as SUPERTMsb-3D) is suitable for simulating the resin flow inside two-dimensional as well as three-dimensional fiber preforms of arbitrary shapes. The use of this computer code is illustrated through sample problems. These problems demonstrate how (with this code) the designer can establish the port and vent locations, opening and closing sequences of ports and vents such that the fiber preform is filled completely in the shortest time with the fewest number of vents.

  16. Measurement of bulk modulus of coal slime pastes and the application in long pipelines delivering pastes%煤泥体积模量测试及在长距离管道输送中的应用∗

    Institute of Scientific and Technical Information of China (English)

    郝雪弟; 刘亚运; 李娜; 石庆伟; 吴淼

    2014-01-01

    为了实现大流量、长距离煤泥输送管道在电厂锅炉燃烧发电中的应用,解决输送过程中存在的膏体返流和管道冲击振动的问题,采用定义法设计了表征煤泥膏体弹性特征的体积弹性模量的测试装置,并利用该装置对煤泥膏体进行了体积弹性模量测试,研究了压力和质量浓度等参数与煤泥膏体体积弹性模量的关系。对测试装置进行了误差分析,并得出了测试误差随着压力的变化规律,最后对某电厂煤泥管道输送系统进行了返流量预测。结果表明,煤泥膏体体积弹性模量随着其质量浓度的降低而减小,并随着压力呈非线性变化,当压力较小时,体积弹性模量随着压力上升而急剧增大;当压力超过10 MP a时,煤泥膏体体积弹性模量在某一稳定值上下小范围的波动,该稳定值随浓度的变化而变化。%In order to achieve the application of long pipelines with large capacity delivering coal slime pastes in the electric power plant,the problems of reversed flow of pastes and pipeline vibration need to be solved.The test device for finding the main parameter of the coal slime deno-ting the elastic property,the bulk modulus of elasticity was presented by using definition method. The bulk modulus of the coal slime have been tested with this device and the relationship with pa-rameters such as mass concentration and pressure have been studied.Besides,the error analysis of the device has been calculated and the change along with different pressure have been figured. Finally,the amount of reversed flow of the pipelines of the electric power plant delivering coal slime have been predicted.The results showed that the bulk modulus of elasticity decreases with the decline of the mass concentration,while it varies non-linearly along with pressure change. When the pressure was low,it increased rapidly with the raise of the pressure.However,it re-mains stable and fluctuates

  17. A molding method to fabricate the waveguide multilayer card

    Institute of Scientific and Technical Information of China (English)

    ZHOU Wang-ren; LIANG Zhong-cheng; GU Min-fen

    2008-01-01

    Waveguide multilayer optical card(WMOC)is a new kind of three-dimensional storage device.A method of fabricating the WMOC using the moMing techniqBe is introduced in this paper.The fabrication of WMOC mainly includes data writing with hot embossing method and multilayer bonding with PDMS material The structure of the WMOC is comisted with Polyearbonate (PC) as the core layer material and Polydimethylsiloxane (PDMS) as cladding layer.The experimental ICSUIts demonstrate that the molding fabrication method is leasible and effective.

  18. Sintering products molded by injecting ceramic and metal powders

    Institute of Scientific and Technical Information of China (English)

    LIU Ping-an; ZENG Ling-ke; LI Xiu-yan

    2005-01-01

    The injection molding products with different volume ratios of ZrO2 ceramic powder to 316L stainless steel powder were prepared. Properties and structure of the products were characterized by X-ray diffraction(XRD),scanning electron microscope(SEM) and transmission electron microscope (TEM). The results show that the compressive stress exists in the products and the bend strength reaches 300 MPa. ZrO2 phase and stainless steel phase are uniform in samples. The toughness of ceramic increases with the increasing the content of stainless steel.Through TEM study of the interface, some crystalline orientation relationships are determined.

  19. The Influence of runner system on production of injection molds

    Directory of Open Access Journals (Sweden)

    Janostik Vaclav

    2016-01-01

    Full Text Available This experimental study describes the influence of runner system on rheological properties during the injection molding process. Economic effects on the amount of production are discussed as well. Autodesk Moldflow Synergy 2016 (Moldflow was used for the study of the injection process. Three suggestions of the runner system, cold runner system, hot runner system and the combination of cold–hot runner system have been promoted. These three variants underwent the rheological and economic analysis. As a result, recommendations for the application of the runner system for the required amount of production have been suggested

  20. Study on soot purifying of molding shop in coking factory

    Institute of Scientific and Technical Information of China (English)

    LI Duo-song; ZHANG Hui; BAI Xiang-yu

    2006-01-01

    Exhaust gas in molding shop was complicated in component and characteristic in Iow thickness asphalt smoke, mass steam-gas and dust. It was difficult to purify the soot with common purifier. So we must consider them roundly and develop new multifunction purifier. PFP multifunction soot purifier was made on the base of design optimization and was installed at Shenhuo Coking Factory in 2004. The combined effects of multi- mechanism in purifier make purifying ratio keep in high level. The remove ratio of smut reaches at 92.8%, and asphalt smoke at 83.7%.

  1. Cleft Lip Repair, Nasoalveolar Molding, and Primary Cleft Rhinoplasty.

    Science.gov (United States)

    Bhuskute, Aditi A; Tollefson, Travis T

    2016-11-01

    Cleft lip and palate are the fourth most common congenital birth defect. Management requires multidisciplinary care owing to the complexity of these clefts on midface growth, dentition, Eustachian tube function, and lip and nasal cosmesis. Repair requires planning, but can be performed systematically to reduce variability of outcomes. The use of primary rhinoplasty at the time of cleft lip repair can improve nose symmetry and reduce nasal deformity. Use of nasoalveolar molding ranging from lip taping to the use of preoperative infant orthopedics has played an important role in improving functional and cosmetic results of cleft lip repair.

  2. Precision glass molding of complex shaped chalcogenide glass lenses for IR applications

    Science.gov (United States)

    Staasmeyer, Jan-Helge; Wang, Yang; Liu, Gang; Dambon, Olaf; Klocke, Fritz

    2016-09-01

    The use of chalcogenide glass in the thermal infrared domain is an emerging alternative to commonly used crystalline materials such as germanium. The main advantage of chalcogenide glass is the possibility of mass production of complex shaped geometries with replicative processes such as precision glass molding. Thus costly single point diamond turning processes are shifted to mold manufacturing and do not have to be applied to every single lens produced. The usage of FEM-Simulation is mandatory for developing a molding process for complex e.g. non rotational symmetric chalcogenide glass lenses in order to predict the flow of glass. This talk will present state of the art modelling of the precision glass molding process for chalcogenide glass lenses, based on thermal- and mechanical models. Input data for modelling are a set of material properties of the specific chalcogenide glass in conjunction with properties of mold material and wear protective coatings. Specific properties for the mold-glass interaction such as stress relaxation or friction at the glassmold interface cannot be obtained from datasheets and must be determined experimentally. A qualified model is a powerful tool to optimize mold and preform designs in advance in order to achieve sufficient mold filling and compensate for glass shrinkage. Application of these models in an FEM-Simulation "case study" for molding a complex shaped non-rotational symmetric lens is shown. The outlook will examine relevant issues for modelling the precision glass molding process of chalcogenide glasses in order to realize scaled up production in terms of multi cavity- and wafer level molding.

  3. Validation of the NeoFilm for Yeast and Mold Method for Enumeration of Yeasts and Molds in Select Foods.

    Science.gov (United States)

    Caballero, Oscar; Alles, Susan; Le, Quynh-Nhi; Mozola, Mark; Rice, Jennifer

    2015-01-01

    NeoFilm Yeast and Mold (Y&M), also known as Sanita-kun Yeasts and Molds, is a simple, effective device used for the enumeration of yeasts and molds. It consists of a nonwoven fabric on which a layer of microbial nutrients is deposited in a film. A 1 mL sample homogenate is applied to the membrane and this, in turn, is incubated for 48-72 h at 25°C. Sample homogenates were prepared using two different diluents for customer convenience: phosphate buffered saline (PBS) and 0.1% peptone water. In comparative testing of breaded chicken nuggets, dry pet food, orange juice concentrate, yogurt, and cake mix, there were statistically significant differences in the counts obtained by the NeoFilm Y&M and U.S. Food and Drug Administration Bacteriological Analytical Manual reference culture methods only in the following instances: medium level for orange juice with PBS as diluent and low level for pet food with 0.1% peptone water as diluent, where reference method counts were higher than those of NeoFilm; medium level for cake mix with PBS, and low and medium levels for cake mix with 0.1% peptone water, where NeoFilm produced higher counts than the reference method. In addition to the method comparison study with five matrixes, robustness and stability/lot-to-lot testing were also performed. Results of robustness testing showed no significant effect on results even with perturbation to three assay parameters simultaneously. Results of testing of three lots of devices ranging in age from 2 to 26 months post-manufacture showed no significant differences in performance.

  4. Effect of Mold Coating Materials and Thickness on Heat Transfer in Permanent Mold Casting of Aluminum Alloys

    Science.gov (United States)

    Hamasaiid, A.; Dargusch, M. S.; Davidson, C. J.; Tovar, S.; Loulou, T.; Rezaï-Aria, F.; Dour, G.

    2007-06-01

    In permanent mold casting or gravity die casting (GDC) of aluminum alloys, die coating at the casting-mold interface is the most important single factor controlling heat transfer and, hence, it has the greatest influence on the solidification rate and development of microstructure. This investigation studies the influence of coating thickness, coating composition, and alloy composition on the heat transfer at the casting-mold interface. Both graphite and TiO2-based coatings have been investigated. Two aluminum alloys have been investigated: Al-7Si-0.3Mg and Al-9Si-3Cu. Thermal histories throughout the die wall have been recorded by fine type-K thermocouples. From these measurements, die surface temperatures and heat flux density have been evaluated using an inverse method. Casting surface temperature was measured by infrared pyrometry, and the interfacial heat-transfer coefficient (HTC) has been determined using these combined pieces of information. While the alloy is liquid, the coating material has only a weak influence over heat flow and the thermal contact resistance seems to be governed more by coating porosity and thickness. The HTC decreases as the coating thickness increases. However, as solidification takes place and the HTC decreases, the HTC of graphite coating remains higher than that of ceramic coatings of similar thickness. After the formation of an air gap at the interface, the effect of coating material vanishes. The peak values of HTC and the heat flux density are larger for Al-7Si-0.3Mg than for Al-9Si-3Cu. Consequently, the apparent solidification time of Al-9Si-3Cu is larger than that of Al-7Si-0.3Mg and it increases with coating thickness.

  5. Direct molding of dry adhesives with anisotropic peel strength using an offset lift-off photoresist mold

    Science.gov (United States)

    Sameoto, D.; Menon, C.

    2009-11-01

    We demonstrate for the first time a wafer scale, directly molded anisotropic dry adhesive made of silicone that can be produced in a two-mask process. We demonstrate that the peel strength of this adhesive is dependent on the amount of overhang of a thin flexible cap on the top of each fiber. By precisely placing the center of this cap offset to the center of the supporting post, the peel strength of the adhesive can be altered when pulled off in different directions.

  6. Flow of Steel in Mold Region During Continuous Casting

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xing-guo; ZHANG Wen-xiao; JIN Jun-ze; J. W. Evans

    2007-01-01

    The particle image velocimetry (PIV) technique was used to study the fluid flow phenomena that occurred during continuous casting, using a water model with dimensions of 1 840 mm×280 mm. Two types of solidified shells, i.e., the smooth type and the coarse type, were used to characterize the dendrite in order to simulate different liquid-solid interfacial conditions. The influence of the nozzle angle and the immersion depth of nozzle, as well as the casting speed on the flow behavior was investigated quantitatively. The results were as follows: (1) There are two large recirculations above and below the fluid jet in the mold, respectively, under the smooth interface condition. However, in the case of the dendrite solidified shell, it was found that the flow velocity of the fluid decreased and more smaller vortices appeared in the upper region of the mold. (2) The angle and the immersion depth of nozzle are two important factors affecting the flow pattern, and they are also capable of bringing about the change in the flow direction. (3) The higher the casting speed, the higher are the jet stream and the impacting point on the narrow face. However, the high casting speed causes serious fluctuation of the meniscus, and correspondingly leads to various defects.

  7. Resin transfer molding of textile preforms for aircraft structural applications

    Science.gov (United States)

    Hasko, Gregory H.; Dexter, H. Benson; Weideman, Mark H.

    1992-01-01

    The NASA LaRC is conducting and supporting research to develop cost-effective fabrication methods that are applicable to primary composite aircraft structures. One of the most promising fabrication methods that has evolved is resin transfer molding (RTM) of dry textile material forms. RTM has been used for many years for secondary structures, but has received increased emphasis because it is an excellent method for applying resin to damage-tolerant textile preforms at low cost. Textile preforms based on processes such as weaving, braiding, knitting, stitching, and combinations of these have been shown to offer significant improvements in damage tolerance compared to laminated tape composites. The use of low-cost resins combined with textile preforms could provide a major breakthrough in achieving cost-effective composite aircraft structures. RTM uses resin in its lowest cost form, and storage and spoilage costs are minimal. Near net shape textile preforms are expected to be cost-effective because automated machines can be used to produce the preforms, post-cure operations such as machining and fastening are minimized, and material scrap rate may be reduced in comparison with traditional prepreg molding. The purpose of this paper is to discuss experimental and analytical techniques that are under development at NASA Langley to aid the engineer in developing RTM processes for airframe structural elements. Included are experimental techniques to characterize preform and resin behavior and analytical methods that were developed to predict resin flow and cure kinetics.

  8. Metal Injection Molding (MIM of Magnesium and Its Alloys

    Directory of Open Access Journals (Sweden)

    Martin Wolff

    2016-05-01

    Full Text Available Current research has highlighted that magnesium and its alloys as biodegradable material are highly suitable for biomedical applications. The new material fully degrades into nontoxic elements and offers material properties matching those of human bone tissue. As biomedical implants are rather small and complex in shape, the metal injection molding (MIM technique seems to be well suited for the near net shape mass production of such parts. Furthermore, MIM of Mg-alloys is of high interest in further technical fields. This study focusses on the performance of MIM-processing of magnesium alloy powders. It includes Mg-specific development of powder blending, feedstock preparation, injection molding, solvent and thermal debinding and final sintering. Even though Mg is a highly oxygen-affine material forming a stable oxide layer on each particle surface, the material can be sintered to nearly dense parts, providing mechanical properties matching those of as cast material. An ultimate tensile strength of 142 MPa, yield strength of 67 MPa, elastic modulus of 40 GPa and 8% elongation at fracture could be achieved using novel organic polymer binders for the feedstock preparation. Thus, first implant demonstrator parts could be successfully produced by the MIM technique.

  9. Chalcogenide material strengthening through the lens molding process

    Science.gov (United States)

    Nelson, J.; Scordato, M.; Lucas, Pierre; Coleman, Garrett J.

    2016-05-01

    The demand for infrared transmitting materials has grown steadily for several decades as markets realize new applications for longer wavelength sensing and imaging. With this growth has come the demand for new and challenging material requirements that cannot be satisfied with crystalline products alone. Chalcogenide materials, with their unique physical, thermal, and optical properties, have found acceptance by designers and fabricators to meet these demands. No material is perfect in every regard, and chalcogenides are no exception. A cause for concern has been the relatively low fracture toughness and the propensity of the bulk material to fracture. This condition is amplified when traditional subtractive manufacturing processes are employed. This form of processing leaves behind micro fractures and sub surface damage, which act as propagation points for both local and catastrophic failure of the material. Precision lens molding is not a subtractive process, and as a result, micro fractures and sub surface damage are not created. This results in a stronger component than one produced by traditional methods. New processing methods have also been identified that result in an even stronger surface that is more resistant to breakage, without the need for post processing techniques that may compromise surface integrity. This paper will discuss results achieved in the process of lens molding development at Edmund Optics that result in measurably stronger chalcogenide components. Various metrics will be examined and data will be presented that quantifies component strength for different manufacturing processes.

  10. Key Odorants of Lazur, a Polish Mold-Ripened Cheese.

    Science.gov (United States)

    Majcher, Małgorzata A; Myszka, Kamila; Gracka, Anna; Grygier, Anna; Jeleń, Henryk H

    2017-02-15

    Application of gas chromatography-olfactometry (GC-O) carried out on the volatile fraction isolated by solvent-assisted flavor evaporation (SAFE) and solid phase microextraction (SPME) from Lazur mold-ripened cheese revealed 17 odor-active compounds. The highest flavor dilution factor (FD) has been obtained for methanethiol (2048) with a burnt odor note and for 2(3)-methylbutanoic acid (2048) with a cheesy, pungent odor. Further quantitation of the 15 most aroma-active compounds allowed for calculation of their odor activity values (OAV). The highest OAVs were obtained for methanethiol (500), 3(2)-methylbutanoic acid (321), 3-(methylthio)propanal (210), 2,3-butanedione (65), dimethyl trisulfide (22), butanoic acid (20), 1-octen-3-ol (18), (Z)-4-heptenal (14), dimethyl disulfide (14), dimethyl sulfide (13), phenylacetaldehyde (6), 2-ethyl-3,5-dimethylpyrazine (5), and acetic acid (4). An aroma recombination experiment showed slight differences in the perception of cheesy/sweaty and moldy/musty notes. To verify the influence of methyl ketones on the aroma profile of mold-ripened cheese, recombinant has been additionally supplemented with 2-pentanone, 2-heptanone, and 2-nonanone in concentrations determined in Lazur cheese. The aroma profile remained unchanged, which would suggest that methyl ketones, in this particular cheese, do not play a significant role in the formation of aroma.

  11. A Nanofluidic Biosensor Based on Nanoreplica Molding Photonic Crystal

    Science.gov (United States)

    Peng, Wang; Chen, Youping; Ai, Wu; Zhang, Dailin

    2016-09-01

    A nanofluidic biosensor based on nanoreplica molding photonic crystal (PC) was proposed. UV epoxy PC was fabricated by nanoreplica molding on a master PC wafer. The nanochannels were sealed between the gratings on the PC surface and a taped layer. The resonance wavelength of PC-based nanofluidic biosensor was used for testing the sealing effect. According to the peak wavelength value of the sensor, an initial label-free experiment was realized with R6g as the analyte. When the PC-based biosensor was illuminated by a monochromatic light source with a specific angle, the resonance wavelength of the sensor will match with the light source and amplified the electromagnetic field. The amplified electromagnetic field was used to enhance the fluorescence excitation result. The enhancement effect was used for enhancing fluorescence excitation and emission when matched with the resonance condition. Alexa Fluor 635 was used as the target dye excited by 637-nm laser source on a configured photonic crystal enhanced fluorescence (PCEF) setup, and an initial PCEF enhancement factor was obtained.

  12. Influence of engineering variables upon the morphology of filamentous molds

    Energy Technology Data Exchange (ETDEWEB)

    Van Suijdam, J.C.; Metz, B.

    1981-01-01

    A model has been described for the influence of growth rate and shear stresses in the fermentor upon the morphology of filamentous molds. The main concept of this model is the dynamic equilibrium between growth and breakup of the hyphae. The latter has been approached according to well-known engineering theories for dispersion of physical systems. Experiments to verify the model with a strain of Tenicillium chrysogenum in batch and continuous culture revealed that the length of the mycelial particles increased with increasing' growth rate and decreased with increasing power input per unit mass in the fermentor. Although this was qualitatively in agreement with the presented model, quantitatively the model had to be rejected. Variation of the tensile strength of the hyphae with age and culturing conditions could have been one of the causes of disagreement. Oxygen tension, varied independently from stirrer speed, in the range of 12-300 mm Hg was shown to have no influence upon the morphology. With respect to the question of possibly using high-energy inputs in industrial mold fermentation in order to decrease hyphal length and suspension viscosity, it was concluded that this is of little practical value. A substantial decrease in hyphal length requires an enormous increase in energy input.

  13. Cellular image classification

    CERN Document Server

    Xu, Xiang; Lin, Feng

    2017-01-01

    This book introduces new techniques for cellular image feature extraction, pattern recognition and classification. The authors use the antinuclear antibodies (ANAs) in patient serum as the subjects and the Indirect Immunofluorescence (IIF) technique as the imaging protocol to illustrate the applications of the described methods. Throughout the book, the authors provide evaluations for the proposed methods on two publicly available human epithelial (HEp-2) cell datasets: ICPR2012 dataset from the ICPR'12 HEp-2 cell classification contest and ICIP2013 training dataset from the ICIP'13 Competition on cells classification by fluorescent image analysis. First, the reading of imaging results is significantly influenced by one’s qualification and reading systems, causing high intra- and inter-laboratory variance. The authors present a low-order LP21 fiber mode for optical single cell manipulation and imaging staining patterns of HEp-2 cells. A focused four-lobed mode distribution is stable and effective in optical...

  14. Multiuser Cellular Network

    CERN Document Server

    Bao, Yi; Chen, Ming

    2011-01-01

    Modern radio communication is faced with a problem about how to distribute restricted frequency to users in a certain space. Since our task is to minimize the number of repeaters, a natural idea is enlarging coverage area. However, coverage has restrictions. First, service area has to be divided economically as repeater's coverage is limited. In this paper, our fundamental method is to adopt seamless cellular network division. Second, underlying physics content in frequency distribution problem is interference between two close frequencies. Consequently, we choose a proper frequency width of 0.1MHz and a relevantly reliable setting to apply one frequency several times. We make a few general assumptions to simplify real situation. For instance, immobile users yield to homogenous distribution; repeaters can receive and transmit information in any given frequency in duplex operation; coverage is mainly decided by antenna height. Two models are built up to solve 1000 users and 10000 users situations respectively....

  15. Engineering Cellular Metabolism.

    Science.gov (United States)

    Nielsen, Jens; Keasling, Jay D

    2016-03-10

    Metabolic engineering is the science of rewiring the metabolism of cells to enhance production of native metabolites or to endow cells with the ability to produce new products. The potential applications of such efforts are wide ranging, including the generation of fuels, chemicals, foods, feeds, and pharmaceuticals. However, making cells into efficient factories is challenging because cells have evolved robust metabolic networks with hard-wired, tightly regulated lines of communication between molecular pathways that resist efforts to divert resources. Here, we will review the current status and challenges of metabolic engineering and will discuss how new technologies can enable metabolic engineering to be scaled up to the industrial level, either by cutting off the lines of control for endogenous metabolism or by infiltrating the system with disruptive, heterologous pathways that overcome cellular regulation.

  16. Gibberellic acid, ozone and 1-methylcyclopropene on the gray mold control in 'Avant Garde' Rose

    DEFF Research Database (Denmark)

    Favero, B.T.; Benato, E.A.; Dias, G.M.;

    Gray mold caused by Botrytis cinerea is considered the major disease of greenhouse grown flowers. The goal of this study was to evaluate the effects of gibberellic acid (GA3), ozone, and 1-MCP, applied on postharvest, on the gray mold control in 'Avant Garde' rose. Rose flowers were artificially ...

  17. Injection molded nanofluidic chips: Fabrication method and functional tests using single-molecule DNA experiments

    DEFF Research Database (Denmark)

    Utko, Pawel; Persson, Karl Fredrik; Kristensen, Anders;

    2011-01-01

    We demonstrate that fabrication of nanofluidic systems can be greatly simplified by injection molding of polymers. We functionally test our devices by single-molecule DNA experiments in nanochannels.......We demonstrate that fabrication of nanofluidic systems can be greatly simplified by injection molding of polymers. We functionally test our devices by single-molecule DNA experiments in nanochannels....

  18. Mold, Mould, Mole-d: The Three M's of Career Development

    Science.gov (United States)

    Amundson, Norman E.

    2008-01-01

    The author explores a creative idea development process wherein one begins by applying the image of "breaking the mold" to career development and then extending the process further by considering other related images. In this article, the related images include synonyms for mold such as mould and mole-d (the mole is a small burrowing animal with…

  19. Gibberellic acid, ozone and 1-methylcyclopropene on the gray mold control in 'Avant Garde' Rose

    DEFF Research Database (Denmark)

    Favero, B. T.; Benato, E. A.; Dias, G. M.;

    2015-01-01

    Gray mold caused by Botrytis cinerea is considered the major disease of greenhouse grown flowers. The goal of this study was to evaluate the effects of gibberellic acid (GA3), ozone, and 1-MCP, applied on postharvest, on the gray mold control in 'Avant Garde' rose. Rose flowers were artificially ...

  20. Low Cost Injection Mold Creation via Hybrid Additive and Conventional Manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Dehoff, Ryan R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Watkins, Thomas R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); List, III, Frederick Alyious [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Carver, Keith [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); England, Roger [Cummins, Inc, Knoxville, TN (United States)

    2015-12-01

    The purpose of the proposed project between Cummins and ORNL is to significantly reduce the cost of the tooling (machining and materials) required to create injection molds to make plastic components. Presently, the high cost of this tooling forces the design decision to make cast aluminum parts because Cummins typical production volumes are too low to allow injection molded plastic parts to be cost effective with the amortized cost of the injection molding tooling. In addition to reducing the weight of components, polymer injection molding allows the opportunity for the alternative cooling methods, via nitrogen gas. Nitrogen gas cooling offers an environmentally and economically attractive cooling option, if the mold can be manufactured economically. In this project, a current injection molding design was optimized for cooling using nitrogen gas. The various components of the injection mold tooling were fabricated using the Renishaw powder bed laser additive manufacturing technology. Subsequent machining was performed on the as deposited components to form a working assembly. The injection mold is scheduled to be tested in a projection setting at a commercial vendor selected by Cummins.