Academic literature on the topic 'Meta3C'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the lists of relevant articles, books, theses, conference reports, and other scholarly sources on the topic 'Meta3C.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Journal articles on the topic "Meta3C"
1
Singh, R. J., and T. Tsuchiya. "Cytogenetics of an unstable trisomie in barley (Hordeum vulgare)." Genome 36, no. 2 (April 1, 1993): 350–55. http://dx.doi.org/10.1139/g93-048.
Full textAbstract:
The origin, identification, meiotic chromosome behavior, and breeding behavior of an unstable trisomic barley were studied. The extra chromosome originated by breakage and fusion of an acrocentric chromosome 3 in a plant from an F2 population of a cross between acrotrisomic 3L3S (2n = 14 + 1 acro3L3S) and a balanced lethal stock, xc. (xantha) ac (albino). The F2 population segregated only for the albino trait. The genotypic constitution of the trisomic plant was ac ac (for both normal chromosome 3) and Ac (for the unstable metacentric chromosome). The unstable extra metacentric chromosome was designated as metacentric 3B (abbreviated as meta3B). Meiotic chromosome behavior in plants with 2n = 14 + 1 meta3B differed from plant to plant and within spikes. Some plants showed only trisomic cells with a chromosome configuration of 1 III + 6 II and 7 II + 1 I at metaphase I, whereas other plants showed both trisomie and disomic cells (7 II) that resulted from the elimination of the extra meta3B. The frequency of ring trivalents was low (6.8%). An average transmission rate of unstable meta3B ranged from 4.3 to 12.9%. The elimination of meta3B, and hence loss of the dominant Ac allele, resulted in albino seedlings as well as white stripes on plants, leaves, and spikes. Chromosome numbers of albino seedlings in the progeny of 2n = 14 + 1 meta3B were all diploid (2n = 14), while green seedlings contained 2n = 14 + 1 meta3B. However, progenies of some spikes of one trisomic plant showed a low frequency of green diploids and metatrisomics (2n = 14 + 1 meta3B), which was attributed to crossing-over.Key words: aneuploid, chromosome elimination, kinetochore, meta3B.
2
Moore, Courtney, Weijue Gao, and Pedram Fatehi. "Cationic Lignin Polymers as Flocculant for Municipal Wastewater." Polymers 13, no. 22 (November 9, 2021): 3871. http://dx.doi.org/10.3390/polym13223871.
Full textAbstract:
The radical polymerization of acid-washed and unwashed softwood kraft lignin with [2-(methacryloyloxy) ethyl] trimethylammonium chloride (METAC) was attempted to investigate the production of lignin-based flocculants for simulated wastewater. The incorporation of METAC onto lignin resulted in a cationic charge density (2.3–3.3 meq/g), increased water solubility (89–96% in neutral pH), and increased molecular weight (70,000–210,000 g/mol) of lignin. The lignin–METAC polymers generated from acid-washed lignin had higher molecular weights than those generated from unwashed lignin. The lignin–METAC polymers showed lower resistance to thermal decomposition than unmodified lignin due to the inclusion of PolyMETAC. The unmodified acid-washed lignin samples did not significantly affect the COD of the wastewater, while the unmodified unwashed lignin samples contributed to the COD, implying that unmodified lignin was not suitable for wastewater treatment. The flocculation of wastewater with lignin–METAC led to the chemical oxygen demand (COD) reduction of 17–23% and total organic carbon (TOC) drop of 51–60%. The lignin–METAC polymer with the highest molecular weight (produced from acid-washed lignin) reached the highest COD removal, while lignin–METAC polymer with the highest charge density (produced from unwashed lignin) reached the highest TOC removal. Focused beam reflectance measurement (FBRM) studies revealed that the lignin–METAC polymer produced from acid-washed lignin with a high molecular weight generated larger and more flocs in wastewater than the lignin–METAC polymer produced from unwashed lignin. The comparison of theoretical and experimental dosages required for neutralizing the charges of wastewater demonstrated that charge neutralization was the main flocculation mechanism, although a bridging mechanism was also involved for component removals from wastewater. The use of 1 mg/L of alum along with 65 mg/L lignin–METAC in a dual coagulation–flocculation system led to higher average phosphorous (42%) and COD (44%) removals than the singular flocculation system only using 65 mg/L of lignin–METAC (with phosphorous removals of 3.4% and COD removals of 18.7%). However, lignin–METAC flocculant slightly increased the ammonia–nitrogen content in both singular flocculation and dual coagulation–flocculation systems due to the residual ammonia content of lignin–METAC. The coagulation–flocculation system determined that the use of lignin–METAC (65 mg/L) could reduce the alum dosage significantly while maintaining a similar organic content reduction of 44% for wastewater.
3
Kohno, Tomoki, Haruaki Kitagawa, Ririko Tsuboi, Fan Deng, Hirohiko Sakai, Tingyi Wu, Yo-Shiuan Fan, Linghao Xiao, and Satoshi Imazato. "Development of Antibacterial Resin Composites Incorporating Poly(METAC) Clusters." Materials 17, no. 4 (February 15, 2024): 896. http://dx.doi.org/10.3390/ma17040896.
Full textAbstract:
This study examined the antibacterial effects and physical properties of a novel resin composite incorporating poly[{2-(methacryloyloxy)ethyl}trimethylammonium chloride] (poly(METAC)), a methacrylate cationic polymer comprising quaternary ammonium compounds (QACs). Resin composites incorporating poly(METAC) were fabricated by adding 6 wt.% METAC aqueous solution to a commercially available resin composite. The FE-SEM/EDS and Raman spec-troscopy analyses showed that METAC was assembled and polymerized in the resin composites after curing. The antibacterial effect was evaluated by inoculating Streptococcus mutans or Strepto-coccus sobrinus suspensions on the surface of cured resin composites, and the experimental resin composites incorporating poly(METAC) clusters exhibited bactericidal effects even after 28 days of ageing. The physical properties of the experimental resin composites were within the ISO-stipulated ranges. Newly fabricated resin composites containing the QAC-based poly(METAC) cluster ex-hibited long-term bactericidal effects against oral bacteria on their surfaces and demonstrated ac-ceptable physical properties for clinical use.
4
Shiga, Toshiki, Hiromitsu Mori, Keiichi Uemura, Ryota Moriuchi, Hideo Dohra, Aika Yamawaki-Ogata, Yuji Narita, Akihiro Saito, and Yohei Kotsuchibashi. "Evaluation of the Bactericidal and Fungicidal Activities of Poly([2-(methacryloyloxy)ethyl]trimethyl Ammonium Chloride)(Poly (METAC))-Based Materials." Polymers 10, no. 9 (August 26, 2018): 947. http://dx.doi.org/10.3390/polym10090947.
Full textAbstract:
Poly([2-(methacryloyloxy)ethyl]trimethyl ammonium chloride) (METAC) and the gels were prepared and evaluated for their bactericidal and fungicidal activities. The antimicrobial properties of poly(METAC) were tested against Escherichia coli (E. coli), Bacillus subtilis (B. subtilis), Saccharomyces cerevisiae (Sa. cerevisiae), methicillin-susceptible Staphylococcus aureus (MSSA), methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa (P. aeruginosa), and Candida albicans (C. albicans). Moreover, the structural forms of the linear and cross-linked poly(METAC) were investigated for their influences on bacterial aggregation, precipitation, and cell-death. To our knowledge, this is the first report on the comparison of the antimicrobial properties of poly(METAC) and poly(METAC)-gels. The bactericidal and fungicidal activities were evaluated by determining minimum inhibitory concentrations (MICs), UV–Vis spectroscopy, and fluorescence and confocal microscopies. The MICs were found to be 123 (MSSA), 123 (MRSA), 123 (P. aeruginosa), 370 (E. coli), 123 (B. subtilis), 370 (C. albicans), and 370 μg/mL (Sa. cerevisiae), as determined by broth dilution, and 370 (MSSA), 370 (MRSA), 370 (P. aeruginosa), 3300 (E. coli), 370 (B. subtilis), 1100 (C. albicans), and >10,000 μg/mL (Sa. cerevisiae), as determined by paper disc diffusion (on solid medium). The poly(METAC)-gels achieved rapid adsorption/precipitation of bacteria via the cationic surface charge. Thus, these poly(METAC)-based polymers can potentially be used as antibacterial materials.
5
Wang, Shoujuan, Fangong Kong, Pedram Fatehi, and Qingxi Hou. "Cationic High Molecular Weight Lignin Polymer: A Flocculant for the Removal of Anionic Azo-Dyes from Simulated Wastewater." Molecules 23, no. 8 (August 11, 2018): 2005. http://dx.doi.org/10.3390/molecules23082005.
Full textAbstract:
The presence of dyes in wastewater effluents made from the textile industry is a major environmental problem due to their complex structure and poor biodegradability. In this study, a cationic lignin polymer was synthesized via the free radical polymerization of lignin with [2-(methacryloyloxy) ethyl] trimethyl ammonium chloride (METAC) and used to remove anionic azo-dyes (reactive black 5, RB5, and reactive orange 16, RO16) from simulated wastewater. The effects of pH, salt, and concentration of dyes, as well as the charge density and molecular weight of lignin-METAC polymer on dye removal were examined. Results demonstrated that lignin-METAC was an effective flocculant for the removal of dye via charge neutralization and bridging mechanisms. The dye removal efficiency of lignin-METAC polymer was independent of pH. The dosage of the lignin polymer required for reaching the maximum removal had a linear relationship with the dye concentration. The presence of inorganic salts including NaCl, NaNO3, and Na2SO4 had a marginal effect on the dye removal. Under the optimized conditions, greater than 98% of RB5 and 94% of RO16 were removed at lignin-METAC concentrations of 120 mg/L and 105 mg/L in the dye solutions, respectively.
6
Xiao, Shengwei, Yuyu Zhao, Shuqi Jin, Zhicai He, Gaigai Duan, Haining Gu, Hongshun Xu, Xingyu Cao, Chunxin Ma, and Jun Wu. "Regenerable bacterial killing–releasing ultrathin smart hydrogel surfaces modified with zwitterionic polymer brushes." e-Polymers 22, no. 1 (January 1, 2022): 719–32. http://dx.doi.org/10.1515/epoly-2022-0055.
Full textAbstract:
Abstract Building long-lasting antimicrobial and clean surfaces is one of the most effective strategies to inhibit bacterial infection, but obtaining an ideal smart surface with highly efficient, controllable, and regenerative properties still encounters many challenges. Herein, we fabricate an ultrathin brush–hydrogel hybrid coating (PSBMA-P(HEAA-co-METAC)) by integrating antifouling polyzwitterionic (PSBMA) brushes and antimicrobial polycationic (P(HEAA-co-METAC)) hydrogels. The smart bacterial killing–releasing properties can be achieved independently by the opposite volume and conformation changes between the swelling (shrinking) of P(HEAA-co-METAC) hydrogel layer and the shrinking (swelling) of PSBMA brushes. The friction test reveals that both METAC and SBMA components support great lubrication. By tuning the initial organosilane (BrTMOS:KH570) ratios, the prepared PSBMA-P(HEAA-co-METAC) coating exhibits different antibacterial abilities from single “capturing–killing” to versatile “capturing–killing–releasing.” Most importantly, 99% of the bacterial-releasing rate can be easily achieved via 0.5 M NaCl treatment. This smart surface not only possesses long-lasting antibacterial performance, only ∼1.09 × 105 cell·cm−2 bacterial residue even after 72 h exposure to bacteria solutions, but also can be regenerated and triggered between water and salt solution multiple times. This work provides a new way to fabricate antibacterial smart hydrogel coatings with bacterial “killing–releasing” functions and shows great potential for biomedical applications.
7
Chang, Cheng, Qing-Fu Wang, Jun-Chao Guo, Duo-Duo Li, Yu-Bo Fan, and Jian-Min Wen. "The Biomechanical Relationship between Hallux Valgus Deformity and Metatarsal Pain." Journal of Healthcare Engineering 2020 (March 26, 2020): 1–7. http://dx.doi.org/10.1155/2020/8929153.
Full textAbstract:
Metatarsal pain is a common pathological outcome in patients with a hallux valgus (HV) deformity. However, the relationship between the degree of HV deformity and metatarsal pain has not been systematically examined. The purpose of the present study was to investigate the correlation between metatarsal pain and the degree of HV deformity. Between October 2017 and September 2018, 512 HV patients (944 feet) participated in an evaluation of their HV angle (HVA) using X-ray images. The participants were divided into four groups corresponding to their HVA (<15°, 15° to 20°, 21° to 40°, or >40°). Load rate, impulse, contact duration, and contact area were measured and recorded as dynamic gait parameters using the RsScan system. Data were evaluated using SPSS statistical software. The visual analog scale (VAS) was used to assess metatarsal pain. For the four HV deformity groups, the peak value of impulse and contact duration was concentrated on the second and third metatarsals (Meta2 and Meta3) (P<0.05); contact area was also shown on metatarsals 1, 2, and 5 (P<0.05). Metatarsal pain on Meta2 had the highest VAS score (VAS: 6.57), followed by Meta3 (Mean VAS: 5.72). In the HV > 40° group, the load location on Meta2 was transferred to Meta1. The percent of pain attributed to Meta2 and Meta3 was also increased in this group. These findings illustrated that metatarsal pain was primarily located on Meta2 and Meta3 in the different degrees of HV deformity. This information can provide the location to target for pain relief and help guide further rehabilitation.
8
Andayani, Santi, and Ni Made Savitri Paramita. "REPRODUKSI WACANA METABO LAW DALAM PEMBENTUKAN STEREOTYPE FAT CHARACTER PADA ANIME JEPANG." IZUMI 7, no. 1 (April 19, 2018): 11. http://dx.doi.org/10.14710/izumi.7.1.11-21.
Full textAbstract:
(Title: The Reproduction Of Metabo Law Discourse In Constructing Fat Characters Stereotype In Japanese Animes) Japanese government through Ministry of Health, Labor and Welfare (MHLW) in 2008 issued the Metabo Law regulation, which is the standard of medical and health guidance that is done specifically with the purpose to decrease the number of obesity which cause the metabolic syndrome. This regulation put the body of each individual to be open to the public. Using Foucault’s perception, this study look how Metabo Law works and how the reproduction of Metabo Law discourses constructing stereotype of fat character in Japanese anime. This study took data from 14 fat character in 13 anime, airing in 2008’s until 2015’s. To complete the data, interview were conducted on 5 Japanese about their understanding about Metabo Law. This study shows that with the normalization process using yearly general checkup and the reproduction of Metabo Law discourses, Japanese government successfully change the Japanese mindset and their behavior in maintained a healthy life style and to stay slim. The stereotype of the fat character that emerge as the product of reproduction of Metabo Law discourses is greedy, careless, cowardly, shy/ have low self-confident, and an otaku.
9
Guan, Xiaolin, Donghai Zhang, Tianming Jia, Yang Zhang, Li Meng, Qijun Jin, Hengchang Ma, Dedai Lu, Shoujun Lai, and Ziqiang Lei. "Intriguingly tuning the fluorescence of AIEgen using responsive polyelectrolyte microspheres." RSC Advances 6, no. 109 (2016): 107622–27. http://dx.doi.org/10.1039/c6ra23380e.
Full textAbstract:
We successfully synthesized counterion-sensitive TPE–METAC polyelectrolyte microspheres and tuned its fluorescence and size by ClO4−, PF6− and TFSI−.
10
Pei, Yi Wen, Jadranka Travas-Sejdic, and David E. Williams. "Synthesis and Characterization of Polysulfobetaines and their Random Copolymers." Materials Science Forum 700 (September 2011): 219–22. http://dx.doi.org/10.4028/www.scientific.net/msf.700.219.
Full textAbstract:
[3-(Methacryloylamino) propyl) dimethyl (3-sulfopropyl) ammonium hydroxide] polymer, known as poly (MPDSAH), and the random copolymers based on methyl methacrylate (MMA), methacryloxyethyltrimethylammonium (METAC) and 3-sulfopropyl methacrylate potassium (SPMA) were synthesized via Reversible Addition-Fragmentation Chain Transfer (RAFT) polymerization technique. Solution properties of these (co) polymers in response to temperature and ionic strength have been studied using dynamic light scattering (DLS). For poly (MPDSAH), polymer size decreased from 500 nm to 10 nm (in diameter) when the polymer aqueous solution was heated up from 15°C to 60°C or added 20 mM sodium chloride. The solution behaviour of poly (METAC-stat-MMA-stat-SPMA) is opposite to that of poly (MPDSAH): the size of polymer increased from 10 nm to 20 nm (in diameter) depending upon the elevating temperature or the addition of salt.
Dissertations / Theses on the topic "Meta3C"
1
Miljana, Prica. "Efekti primene različitih postupaka remedijacije na imobilizaciju teških metala u sedimentu." Phd thesis, Univerzitet u Novom Sadu, Prirodno-matematički fakultet u Novom Sadu, 2009. https://www.cris.uns.ac.rs/record.jsf?recordId=73282&source=NDLTD&language=en.
Full textAbstract:
Predmet izučavanja ove disertacije, osim poređenja različitih metoda procene rizika na osnovu karakterizacije kvaliteta sedimenta vodotokova Vojvodine, bilo je i ispitivanje mogućnosti imobilizacije teških metalau sedimentu primenom različitih remedijacionih tehnika kao i određivanje njihove efikasnosti (npr. solidifikacija/stabilizacija silikatnim materijalima, portland cementom, kalcijum-oksidom itd.) u zavisnosti od brojnih faktora. Osim pseudo-ukupnog sadržaja metala određene su i specifičnije frakcije metala sa posebnimosvrtom na određivanje potencijalno biodostupnih frakcija.Rezultati su ukazali da je naosnovu holandskih preporuka sediment pojedinih vodotokova Vojvodine (Begej, DTD-kanal,Nadela, Sava-Šabac) zagađen metalima (klasa 4) i da je neohodno izmuljivanje i remedijacija. Prema USEPA i kanadskim preporukama, neki uzorci su potencijalno toksični, ali nije zabeležena akutna toksičnost za test vrste u pornoj vodi. Za neke uzorke, i pored visoke pseudo-ukupne koncentracije (klasa 4), nije potvrđena potencijalna toksičnost na osnovu odnosa kiselog volatilnog sulfida i simultano ekstrahovanih metala. Dok se ne primene skuplje metode remedijacije i tretmana sedimenta, najbolje rešenje je izolovano skladištenje na specijalnim deponijama. Naredni koraci bi trebali da budu usresređeni na kontrolu i sprečavanje zagađenja kako bi se obezbedilo da revitalizacija ovih vodotoka ima trajni pozitivan uticaj na životnu sredinu i nesmetanu i bezbednu plovidbu, kao i na primenu određenih remedijacionih metoda. Poređenje rezultata koji su dobijeni različitim procenama kvaliteta sedimenta pokazalo je da ponekad nije dovoljan jedan pristup i da je potrebno je uključiti metode procene biodostupnosti, biotestove i aspekt radioaktivnosti. U uzorku sedimenta koji je korišćen za ispitivanje efikasnosti remedijacionih tretmana, pokazano je da cink, nikal i olovo imaju visok rizik po okolinu, jer seprocenat metala u izmenljivoj i karbonatnoj fazi kretao od 40.1 do 45.2%. Cr i Cd imaju umeren rizik, dok je bakar prisutan u ovim frakcijama u koncentraciji koja predviđa nizak rizik (5.3%). Ovo je u skladu i sa rezultatima analize porne vode i simultano ekstrahovanih metala i kiselog volatilnog sulfida.Istraživanje prikazano u radu je dalo odgovor na pitanje da li remedijacija može uspešno da ukloni zagađenje, u smislu imobilizacije metala u stanje kada oni više neće biti opasnost po okolinu. Svi primenjeni tretmani doveli su dosmanjenja procenta kumulativno izluženih metala iz S/S smeša, ali nijedna smeša tretiranog sedimenta i ispitivanih imobilizacionih agenasa ne pripada grupi inertnog otpada ukoliko se kumulativne izlužene koncentracije metala porede sa koncentracijama koje za otpad propisuje Evropska Unija (2003/33/EC). Ukoliko nam je cilj dobijanje nehazardnog otpada onda moramo primeniti u tretmanu sedimenta kontaminiranog metalima najmanje 30% imobilizaconih agenasa (cementa, kalcijum-oksida). Najveća efikasnost u imobilizaciji metala postignuta je korišćenjem cementa i kalcijum-oksida u smeši (30% cementa i 10% kalcijum-oksida) i primenom termičkog tretmana na višoj temperaturi (11000C) sa glinom (20% gline) što je zaključeno na osnovu koeficijenata difuzije i indeksa izlužljivosti. Dominantan mehanizam izluživanjametala iz ovih smeša je difuzija.This work is concerned with the comparison of the different methods of metal risk assessment in sediments based on examination of the qualityof water courses in Vojvodina. Besides, it deals with the possibility of applying remediation treatments of contaminated sediment and with the efficiency of the different methods, that is the techniques, for immobilization of sediment heavy metals by applying S/S and thermal treatments. A dominant mechanism is proposed for the process of leaching ofthe metals from treated mixtures.Comparison of the results obtained by the different methods of sediment quality assessment showed that in some cases one approach to solving this problem is not sufficient. Metal concentrations in particular sediment samples (the Begej, the DTD Canal, the Nadela, the Sava at Šabac) indicate the presence of contamination, the analyzed samples being of Class 4. According to the Dutch regulations, a sedimentof Class 4 is of unacceptable quality and requires urgent intervention in the sense of sediment dredging, disposal into special depots, and, if possible, remediation. For some samples, despite a high pseudo-total concentration (Class 4), no potential toxicity was confirmed onthe basis of the ratioof the acidic volatile sulfide and simultaneously extracted metals. The results showed that, apart from chemical analyses, biological tests are also necessary, but also sequential extraction analysis, which can more clearly define the way of metal binding to the particular sediment fractions, to allow a more reliable prediction of metal mobility, potential toxicity and bioavailability. In the analysis of sediment quality it is also necessary toinclude the aspect of radioactivity, as it has been shown that the results of this analysis can, not only confirm some of the results of the other analyses, but also indicate the sediment age, origin of contamination and potential toxicity.The subsequent steps should be directed to the control and prevention of contamination, in order to ensure that the water course reviatalization has a lasting positive effect on the environment, an unimpared and safe navigation and application of remediation methods.In the sediment sample (Class 4) that was usedfor the examination of the efficiency of it appeared that zinc, nickel and lead exhibit a high risk, as the percentages of these metals in the exchangeable and carbonate phases were in the range from 40.1 to 45.2%. On the other hand, chromium and cadmium exhibited a moderaterisk, whereas copperin these fractions was present at the levels corresponding to a low risk (5.3%). This is alsoin agreement with the results of pore water analysis and simultaneously extracted metals and acid volatile sulphide examinations.The investigations presented in this work provided an answer to the question whetehr the remediation can successfully remove the contamination in the sense of the immobilization of metals in a state that will not be harmful tothe environment. All the treatments applied yielded a decrease of the percentage of cumulatively leached metals from the S/S mixtures, but none of the mixtures of treated sediments with the tested immobilization agents belongs to the group of inert materials if the cumulative leached concentrations are compared with the concntrations for the wastes given by the EU legislation (2003/33/EC). Ifthe goal is to obtain a non-hazardous material it is necessary to treat the contaminatedsediment with at least 30% of the immobilizing agent (cement or calcium oxide). Based on the diffusion coefficients and leachability index, the highest immobilization efficiency was achieved using a mixture of cement and calcium oxide (30% of cement and 10% of CaO) and by applying thermal treatment at a higher temperature (11000C) with clay (20%). A dominant mechanism of leaching metals from these mixtures is diffusion.
2
Foutel--Rodier, Théo. "Genome-wide effects of T4 phage Ndd protein expression on the Escherichia coli nucleoid." Electronic Thesis or Diss., Sorbonne université, 2021. http://www.theses.fr/2021SORUS553.
Full textAbstract:
La principale partie de ma thèse s’intéresse aux principes d'organisation du génome de la bactérie Escherichia coli. Le génome des bactéries est contenu dans le nucléoïde, un espace fortement organisé par de nombreux facteurs tels que la transcription, le sur-enroulement de l'ADN ou la présence de protéines spécifiques. Toutefois, les mécanismes précis qui régissent l'organisation du nucléoïde restent vaguent. La protéine Ndd du phage T4 provoque une désorganisation radicale du nucléoïde quand elle est exprimée chez E. coli. J'ai utilisé cette protéine Ndd pour tenter de révéler des structures encore inconnues liées à l'organisation du nucléoïde. En utilisant un nouveau système d'expression de Ndd chez E. coli il a été possible de montrer que cette protéine impacte l'ensemble du génome d'E. coli, aussi bien structurellement que transcriptionnellement. Des études en Hi-C ont permis de révéler que la structuration locale du nucléoïde n'est pas affectée par la présence de Ndd. Toutefois, l'expression de Ndd provoque une altération du profil de réplication d'E. coli avec une possible surreplication de la région proximale de l'origine de réplication. Nous avons aussi observé que l'expression de Ndd depuis le chromosome menait à des conséquences très différentes de son expression depuis un plasmide. La recherche de partenaires de Ndd qui pourraient expliquer ces effets par un screen dCas9 n'a donné que peu de candidats qui sont en cours de validation. Nous montrons ici que Ndd semble agir sur un ou des aspects précis mais encore indéterminés de l'organisation du nucléoïde et potentiellement indépendamment de la participation de gènes d'E. coliThe main project of my PhD concerned the principles of organization of the genome of the bacterium Escherichia coli. Bacterial genomes are held in the nucleoid, a space highly organized by many factors such as transcription, DNA supercoiling or the presence of specific proteins. However, some of the precise mechanisms that govern its organization remain unclear. The Ndd protein from phage T4 causes a radical disorganization of the nucleoid when expressed in E. coli. I used this Ndd protein to try to reveal previously unknown structures related to nucleoid organization. Using a novel expression system for Ndd in E. coli, it was possible to show that this protein impacts the entire genome of E. coli, both structurally and transcriptionally. Hi-C studies revealed that the Ndd-disrupted nucleoid remains locally structured in a manner similar to a normal nucleoid. However, Ndd expression causes an alteration in the replication profile of E. coli with possible over-replication at the origin of replication. We also observed that expression of Ndd from the chromosome leads to very different consequences than its expression from a plasmid. The search for a partner of Ndd that could explain these effects by a dCas9 screen yielded few candidates that are currently undergoing validation. Here we show that Ndd appears to act on one or more specific aspects of nucleoid organization and potentially independently of the involvement of genes from E. coli
3
Silva, Marcio Wagner da. "Efeitos da adição de metais básicos aos catalisadores à base de Pd e Ru para a hidrodescloração do pentaclorofenol." [s.n.], 2010. http://repositorio.unicamp.br/jspui/handle/REPOSIP/266936.
Full textAbstract:
Orientadores: Antonio José Gomez Cobo, Antonio Guerrero RuizTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química
Made available in DSpace on 2018-08-17T07:20:21Z (GMT). No. of bitstreams: 1 Silva_MarcioWagnerda_D.pdf: 2089172 bytes, checksum: f1cfbcb71bbf10a37c5a4215dbf395c6 (MD5) Previous issue date: 2010
Resumo: Alguns compostos organoclorados são motivo de grande preocupação, em razão da elevada toxicidade e persistência, tanto no meio ambiente quanto em organismos vivos. Dentre tais compostos, encontra-se o pentaclorofenol, utilizado para a conservação de madeira e na proteção de lavouras. Uma das tecnologias mais promissoras para o tratamento dessa classe de compostos tóxicos é a hidrodescloração catalítica, através da qual é possível recuperar a matéria-prima utilizada na síntese do contaminante. Embora diferentes catalisadores possam ser utilizados nesta reação, destacam-se os sólidos à base de Pd e Ru, notadamente devido à maior atividade catalítica. No entanto, os elevados preços destes metais nobres podem aumentar significativamente os custos do processo. Nesse contexto, o objetivo do presente trabalho é estudar os efeitos da presença dos metais básicos Fe e Ni em catalisadores à base de Pd e Ru, destinados à hidrodescloração do pentaclorofenol em fase líquida. Para tanto, catalisadores monometálicos e bimetálicos, suportados em alumina (Al2O3) ou titânia (TiO2), foram preparados a partir dos precursores clorados, através do método de co-impregnação a seco. Os sólidos obtidos foram caracterizados por meio das técnicas de adsorção de N2 (método BET), microscopia eletrônica de varredura com espectrometria de energia dispersiva de raios-X (MEV-EDX), espectroscopia fotoeletrônica de raios-X (XPS), redução à temperatura programada (TPR) e microscopia eletrônica de transmissão (MET). A hidrodescloração do pentaclorofenol foi conduzida num reator Parr® do tipo "slurry", à temperatura de 383 K e sob pressão de H2 de 0,5 MPa. Na reação de interesse, a adição de Ni ao catalisador de Ru/TiO2 diminui a atividade catalítica, porém mantém a elevada seletividade de cicloexanol, possibilitando, portanto, uma diminuição do custo do catalisador, sem perda de seletividade. Já para o catalisador de Pd/TiO2, a presença de Ni também diminui a atividade catalítica, assim como observado no caso do catalisador de Ru/TiO2, mas verifica-se uma diminuição da seletividade de fenol. Por sua vez, a adição de Fe ao catalisador de Pd/TiO2 tem pouca influência sobre a atividade e a seletividade, possibilitando, assim, uma significativa diminuição do custo do catalisador, sem prejuízo do desempenho catalítico. Os comportamentos catalíticos observados são analisados e interpretados à luz dos resultados obtidos através das caracterizações dos sólidos, assim como das informações disponíveis na literatura
Abstract: Some organic chlorine compounds are of great concern, because of high toxicity and persistence, both the environment and in living organisms. Among these compounds, is the pentachlorophenol, which is used to Wood conservation and for the protection of crops. A very promising technology to treating this class of toxic compounds is the catalytic hydrodechlorination, through which it is possible the recovery of raw material used in the synthesis of the contaminant. Although various catalysts may be used in this reaction, we highlight the solids Pd and Ru, mainly due to higher catalytic activity. However, the high prices of these noble etals can increase significantly the process costs. In this context, the objective of this work is to study the effects of base metals addition, Fe and Ni, in the catalysts based on Pd and Ru, for the pentachlorophenol hydrodechlorination in liquid phase. For this, monometallic and bimetallic catalysts, supported in alumina (Al2O3) or titanium oxide (TiO2), were prepared from chlorinated precursors by the incipient impregnation method. The obtained solids were characterized by techniques of N2 adsorption (BET method), scanning electronic microscopy with X-ray spectrometry analysis (EDX), X-ray photoelectron spectroscopy (XPS), temperature programmed reduction (TPR) and transmission electronic microscopy. The pentachlorophenol hydrodechlorination was carried out in a "slurry" Parr® reactor, at the temperature of 373 K under the hydrogen pressure of 0,5 MPa. In the interest reaction, the addition of Ni to the Ru/TiO2 catalysts reduces the catalytic activity, but the high cyclohexanol selectivity is maintained, enabling thus, decrease the catalyst cost, without loss of selectivity. To the Pd/TiO2 catalyst, the i presence reduce the catalytic activity, like to the observed to the Ru/TiO2 case, but is verified the decreasing of phenol selectivity. In turn, the Fe addition to the Pd/TiO2 catalyst has little influence on the activity and selectivity, leading thus to a significant decrease in the catalyst cost, without prejudice to the catalytic performance. The observed catalytic behaviors are analyzed and interpreted based in the results obtained through the characterization of solids, as well as information available in the literature
Doutorado
Sistemas de Processos Quimicos e Informatica
Doutor em Engenharia Química
4
Mendonça, Marília Assunção. "Reator contínuo com leito de lodo biológico anaeróbio para a remoção de íons metálicos em solução aquosa /." Jaboticabal, 2016. http://hdl.handle.net/11449/142849.
Full textAbstract:
Orientador: Roberto Alves OliveiraCoorientador: Allynson Takehiro Fujita
Banca: Mariana Carina Frigieri
Banca: Luciano dos Santos Rodrigues
Resumo: Reatores contínuos com leito de lodo biológico anaeróbio, in natura e seco em estufa, foram utilizados para a remoção de metais (Cu+2, Mn+2 e Zn+2) em solução aquosa. Com o lodo in natura avaliou-se o efeito conjunto da bioacumulação e biossorção; e com o lodo seco em estufa o efeito exclusivo da biossorção. Foram utilizadas baixas concentrações de Cu+2, Mn+2 e Zn+2 (0,01 a 5,00 mg L-1), tendo em vista que para a ocorrência de bioacumulação devem ser mantidas condições não tóxicas para os micro-organismos. Portanto, os resultados poderão ser aplicados para o pós-tratamento de efluentes com concentrações remanescentes desses metais, que necessitem de polimento para a disposição final, atendendo aos limites legais de qualidade de água do corpo receptor. Os lodos utilizados foram coletados de reatores anaeróbios horizontal (RAH) e de fluxo ascendente com manta de lodo (UASB) utilizados no tratamento de águas residuárias de suinocultura. A temperatura foi controlada a 20°C em todos os ensaios. Foram avaliadas vazões de 5, 10 e 15 mL min-1, valores de pH 4,0 e 6,0 e concentrações de 0,01, 0,5 e 1,0 mg L-1 de Cu2+ e Mn2+, e de 0,05; 2,5 e 5,0 mg L-1 de Zn2+. O pH ótimo para a remoção de Mn2+ e Zn2+ foi 4,0 e para o Cu2+ não foi verificada diferença. A maior eficiência foi encontrada quando utilizou-se os menores valores de concentração e fluxo para os três biossorventes avaliados. Foi verificado que os valores de concentração de metais utilizados demonstraram não serem tóxicos para... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Continuous reactors with anaerobic biological sludge bed, in nature and dry in an oven, were used for removal of metals (Cu+2, Mn+2 and Zn+2 ) in aqueous solution. With the sludge in natura it was evaluated the combined effect of bioaccumulation and biosorption; and the dry sludge in greenhouse sole effect of biosorption. It was used lower concentrations of Cu+2, Mn+2 and Zn+2 (0.01 to 5.00 mg L -1 ), considering that for bioaccumulation occurring should be kept non-toxic conditions for the micro-organisms. Therefore, the results can be applied to the posttreatment of effluents with remaining concentrations of these metals, which require polishing to final disposal, meeting the legal limits of quality of the receiving water body. The used sludges were collected from horizontal anaerobic reactors (RAH) and ascendant upflow sludge blanket (UASB) used in the treatment of swine wastewater. The temperature was controlled at 20°C in all tests. It was analyzed outputs of 5, 10 and 15 ml min-1, pH values 4.0 and 6.0 and concentrations of 0.01, 0.5 and 1.0 mg L- 1 Cu+2 and Mn+2, and 0.05; 2.5 and 5.0 mg L -1 Zn+2 . The optimum pH for the removal of Mn+2 and Zn+2 was 4.0 and the Cu+2 it was not verified difference. The highest efficiency was found when it was used the lowest values of concentration and flux for all three reviews biosorbents. It has been found that the metals concentration values used proved not to be toxic to cells of microorganisms present in the sludge in nature,... (Complete abstract click electronic access below)
Mestre
5
Barrios, André Nozomu Sadoyama [UNESP]. "Modelagem térmica para avaliação da temperatura no fresamento de aços para moldes e matrizes." Universidade Estadual Paulista (UNESP), 2013. http://hdl.handle.net/11449/94485.
Full textAbstract:
Made available in DSpace on 2014-06-11T19:27:13Z (GMT). No. of bitstreams: 0
Previous issue date: 2013-08-23Bitstream added on 2014-06-13T20:35:21Z : No. of bitstreams: 1
barrios_ans_me_ilha.pdf: 1240045 bytes, checksum: a46aee2a6cd45b28e7f169c070d0d6bb (MD5)A usinagem dos metais não é um processo completamente compreendido devido à sua natureza altamente não linear e ao complexo acoplamento entre deformação e o campo de temperatura. O processo de deformação é altamente concentrado em uma zona pequena e as temperaturas geradas nas zonas de deformação afetam ambas a ferramenta e a peça. Conhecendo o fluxo de calor gerado pelo processo de usinagem e, assim, o campo de temperatura, podem-se determinar as melhores condições de corte e também projetar novos produtos com melhor desempenho. Dada a grande importância do estudo térmico para a usinagem, muitas pesquisas continuam hoje sendo desenvolvidos. Este trabalho objetivou estudar a transferência de calor no processo de fresamento de topo do aço comercial VP100, empregado na fabricação de moldes e matrizes. Propôs-se, para isso, um modelo térmico tridimensional resolvido por um método numérico para estimar dois parâmetros: o fluxo líquido de calor e coeficiente de transferência de calor convectivo. Os parâmetros foram estimados através da implementação de um rotina computacional desenvolvida, que teve como dados de entrada as curvas de temperatura experimental do processo de usinagem para um fluido de corte sintético, semissintético e usinagem a seco, utilizando duas velocidades de corte: 200 e 450 m/min. Ademais, foram analisados o perfil de microdureza e a caracterização microestrutural dos corpos de prova, além do desgaste de flanco máximo das ferramentas após a usinagem. Constatou-se que o fluido de corte e a velocidade de corte influenciaram de forma significativa o resfriamento do corpo de prova. Além disso, a usinagem não afetou a microdureza abaixo da superfície fresada da peça, mas a microestrutura até 10 μm de profundidade deformou-se na direção do...
Machining of metals is a process not completely understood because of the highly nonlinear nature and the complex interaction between deformation and temperature field. The process of deformation is highly concentrated in a small zone and the temperatures generated in the deformation zones affect both tool and workpiece. Knowing the heat flux generated by the machining process and thus the temperature field, best conditions for cutting and also for design of new products with improved performance can be determined. Because of the great importance of the thermal effect for machining, several researches have been developed nowadays. This research aimed to study the heat transfer end milling process in commercial VP100 steel, used for producing molds and dies. Thus, a tridimensional thermal model solved by a numerical method was proposed to estimate two parameters: net heat flux and coefficient of convective heat transfer. The parameters were estimated by using computational programming where the input data were temperature curves of the end milling process when using synthetic and semi-synthetic cutting fluid, and dry machining at 200 and 450 m/min cutting speeds. In addition, microhardness and microstructure of workpiece as well as tool wear were analyzed after machining. Cutting fluid and cutting speed significantly influenced on workpiece cooling. Besides, milling process did not affect the part microhardness beneath machined surface, but microstructure up to 10 μm depth was deformed in feed direction of tool, which presented an initial maximum flank wear similar for all cutting conditions (VBBmax ≅ 0.1 mm). Synthetic and semi-synthetic cutting fluids did not presented different cooling capabilities, generating... (Complete abstract click electronic access below)
6
Barrios, André Nozomu Sadoyama. "Modelagem térmica para avaliação da temperatura no fresamento de aços para moldes e matrizes /." Ilha Solteira, 2013. http://hdl.handle.net/11449/94485.
Full textAbstract:
Orientador: Alessandro Roger RodriguesBanca: João Batista Campos Silva
Banca: Paulo André de Camargo Beltrão
Resumo: A usinagem dos metais não é um processo completamente compreendido devido à sua natureza altamente não linear e ao complexo acoplamento entre deformação e o campo de temperatura. O processo de deformação é altamente concentrado em uma zona pequena e as temperaturas geradas nas zonas de deformação afetam ambas a ferramenta e a peça. Conhecendo o fluxo de calor gerado pelo processo de usinagem e, assim, o campo de temperatura, podem-se determinar as melhores condições de corte e também projetar novos produtos com melhor desempenho. Dada a grande importância do estudo térmico para a usinagem, muitas pesquisas continuam hoje sendo desenvolvidos. Este trabalho objetivou estudar a transferência de calor no processo de fresamento de topo do aço comercial VP100, empregado na fabricação de moldes e matrizes. Propôs-se, para isso, um modelo térmico tridimensional resolvido por um método numérico para estimar dois parâmetros: o fluxo líquido de calor e coeficiente de transferência de calor convectivo. Os parâmetros foram estimados através da implementação de um rotina computacional desenvolvida, que teve como dados de entrada as curvas de temperatura experimental do processo de usinagem para um fluido de corte sintético, semissintético e usinagem a seco, utilizando duas velocidades de corte: 200 e 450 m/min. Ademais, foram analisados o perfil de microdureza e a caracterização microestrutural dos corpos de prova, além do desgaste de flanco máximo das ferramentas após a usinagem. Constatou-se que o fluido de corte e a velocidade de corte influenciaram de forma significativa o resfriamento do corpo de prova. Além disso, a usinagem não afetou a microdureza abaixo da superfície fresada da peça, mas a microestrutura até 10 μm de profundidade deformou-se na direção do... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Machining of metals is a process not completely understood because of the highly nonlinear nature and the complex interaction between deformation and temperature field. The process of deformation is highly concentrated in a small zone and the temperatures generated in the deformation zones affect both tool and workpiece. Knowing the heat flux generated by the machining process and thus the temperature field, best conditions for cutting and also for design of new products with improved performance can be determined. Because of the great importance of the thermal effect for machining, several researches have been developed nowadays. This research aimed to study the heat transfer end milling process in commercial VP100 steel, used for producing molds and dies. Thus, a tridimensional thermal model solved by a numerical method was proposed to estimate two parameters: net heat flux and coefficient of convective heat transfer. The parameters were estimated by using computational programming where the input data were temperature curves of the end milling process when using synthetic and semi-synthetic cutting fluid, and dry machining at 200 and 450 m/min cutting speeds. In addition, microhardness and microstructure of workpiece as well as tool wear were analyzed after machining. Cutting fluid and cutting speed significantly influenced on workpiece cooling. Besides, milling process did not affect the part microhardness beneath machined surface, but microstructure up to 10 μm depth was deformed in feed direction of tool, which presented an initial maximum flank wear similar for all cutting conditions (VBBmax ≅ 0.1 mm). Synthetic and semi-synthetic cutting fluids did not presented different cooling capabilities, generating... (Complete abstract click electronic access below)
Mestre
7
Ventura, Luciana Maria Baptista. "Processo de separação por membranas para remoção de sulfato de níquel e zinco de efluente sintético de indústrias metal-mecânicas." Universidade do Estado do Rio de Janeiro, 2008. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=3053.
Full textAbstract:
Fundação de Amparo à Pesquisa do Estado do Rio de JaneiroO objetivo do presente trabalho foi investigar o desempenho de membranas comerciais e funcionalizadas na remoção de metais pesados de efluentes sintéticos, simulando os efluentes gerados pelas indústrias metal-mecânicas. As membranas funcionalizadas foram preparadas em laboratório a partir de diferentes poli (éter imidas) sulfonadas, SPEI, que apresentavam alta hidrofilicidade e capacidade de troca iônica. As permeabilidades hidráulicas das membranas de SPEI aumentaram com o grau de sulfonação. Porém, as rejeições foram ainda muito baixas comparadas as membranas comerciais. Por esta razão, algumas membranas comerciais (NF-90, SW30, HRP98PP e BW30LE) foram investigadas e avaliadas quanto ao comportamento da permeabilidade de água e o grau de rejeição a metais pesados. Os resultados mostraram que a membrana de osmose inversa de baixa energia (BW30LE) tinha o melhor fluxo de água (48,44 L/h.m2) e grau de rejeição a cádmio (98%). Logo, ela foi selecionada para o tratamento dos efluentes sintéticos de indústrias metal-mecânicas contendo níquel e zinco. As indústrias da região de Valencia, na Espanha, forneceram amostras de seus efluentes para análise quantitativa, possibilitando o prepararo de soluções sintéticas modelos. Os resultados foram obtidos variando algumas condições de permeação, tais como a força motriz, o pH e a concentração dos metais na solução de alimentação. Os resultados indicaram que o processo de osmose inversa com a membrana BW30LE é altamente adequado para o tratamento de efluentes contendo metais pesados
The presente work aims to investigate the performance of new functionalized membranes and commercial membranes for heavy metal removal from aqueous effluents. The functionalized membranes were prepared from different sulfonated polyetherimide, SPEI, exhibiting high hydrophilicity and ion exchange capacity. The water permeability of SPEI membranes increased with the sulfonation degree, but with lower saline rejection than commercial membranes. Therefore, commercial membranes (NF-90, SW30, HRP98PP and BW30LE) were used to investigate the relationship between the water permeability and the metals retention. The highest water flux (48.44 L/h.m2) and cadmium rejection (98%) were observed using a reverse osmosis membrane (BW30LE). Then, it was selected to investigate the permeation of a synthetic wastewater containing nickel and zinc as poluted elements. The synthetic solutions were prepared considering samples supplied by industries in the Valencia region, in Spain, which were analyzed quantitatively. The permeation results showed that the membrane performance changed with the driven force (pressure), the pH solution and the metals concentration. The BW30LE membrane showed the best performance for removal of heavy metal in the wastewater treatment
8
Bastos, Silvio Cesar. "Efeito do aquecimento por indução eletromagnetica de tubos sem costura utilizados em motores a diesel." [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/264397.
Full textAbstract:
Orientador: Sergio Tonini ButtonDissertação (mestrado profissional) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica
Made available in DSpace on 2018-08-14T09:44:38Z (GMT). No. of bitstreams: 1 Bastos_SilvioCesar_M.pdf: 4555280 bytes, checksum: 806976ee18b42ffb327e7bb279b89f96 (MD5) Previous issue date: 2009
Resumo: Este trabalho apresenta um estudo sobre o efeito dos processos de recalque a frio e aquecimento por indução eletromagnética sobre as características da microestrutura e dureza do material de tubo de aço sem costura que é utilizado no transporte de fluxo de combustível em sistema de injeção de alta pressão. Por conduzir combustível, a característica de vedação é crítica para as interfaces de montagem destes tubos. Esta interface tem perfil cônico gerado pelo processo de recalque. A microestrutura obtida na região de vedação pode influenciar na dureza do material devido à conformação plástica ocasionada durante processo de recalque de perfil. Os valores de microdureza observados na região de recalque tendem a estar acima da dureza encontrada no material antes da conformação. Este acréscimo de dureza pode influenciar na vedação ocasionando vazamentos, caso o perfil cônico não tenha acomodação uniforme com o perfil da contra-peça, sendo esta o ""rail"" de distribuição ou a bomba de alta pressão de combustível. O processo de aquecimento por indução pode em condições controladas proporcionar alteração da microestrutura e dureza do material, conforme aquecimento e resfriamento desejados.
Abstract: This paper presents a study about the effect of cold upsetting and electromagnetic induction heating on microstructure and hardness characteristics of steel seamles pipe. This pipe studied is applied in fuel flow transport of high pressure fuel system. As fuel is transported the pipe sealing characteristic is critical on assembly interfaces of this pipe. This interface has conic profile produced at upsetting process. The hardness values observed on cold upsetting pipe has a trend to be higher than raw material. There microstructure changed can cause leakage if sealing contact area between conic profile of components has not accommodation enough, being high pressure pump or "rail". The hardness increase can reduce this sealing contact reducing deformation after tight-fitting. The induction heating process under controlled conditions can furnish change of microstructure and hardness material suitable for leak-tightness.
Mestrado
Materiais e Processos de Fabricação
Mestre em Engenharia Mecânica
9
Aguiar, Marcelo Mendes de. "Análise da influência das condições de corte sobre o fresamento em acabamento de aços endurecidos usando altas velocidades." [s.n.], 2012. http://repositorio.unicamp.br/jspui/handle/REPOSIP/264165.
Full textAbstract:
Orientador: Anselmo Eduardo DinizDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica
Made available in DSpace on 2018-08-19T18:33:44Z (GMT). No. of bitstreams: 1 Aguiar_MarceloMendesde_M.pdf: 3795090 bytes, checksum: a76ee2a93e8e7595881459d7a6d71b50 (MD5) Previous issue date: 2012
Resumo: Normalmente, a utilização de aços ferramenta endurecidos, juntamente com as formas complexas típicas das peças utilizadas na área de moldes e matrizes, oferecem dificuldade na usinagem por fresamento, principalmente nas operações de acabamento que exijam o uso de ferramentas longas. A técnica de fresamento HSM (High Speed Machining - usinagem em altas velocidades, ou ainda High Speed Milling - fresamento em altas velocidades) tem se tornado uma alternativa para realizar este tipo de usinagem, reduzindo, ou às vezes até eliminando operações de eletro-erosão e polimento. Tipicamente, as fresas de pastilhas de metal duro intercambiáveis tem sido usadas em operações de desbaste e semi-acabamento, enquanto nas operações de acabamento ou em usinagem de geometrias que exijam ferramentas com pequenos diâmetros ainda predomina o uso de fresas inteiriças. O objetivo principal deste estudo é avaliar a influência de cinco variáveis de processo de fresamento com alta velocidade de corte, sobre o acabamento da superfície usinada. A influência do desgaste das ferramentas sobre o acabamento superficial, ao longo de 400 minutos de usinagem, também foi avaliado, além de uma comparação entre ferramentas inteiriças de metal duro e ferramentas de pastilha intercambiável montada em corpo de metal duro, a fim de avaliar a viabilidade técnica do uso deste segundo tipo de ferramenta, em substituição às tradicionais fresas inteiriças utilizadas em operações de acabamento. Na maioria dos experimentos realizados, pequenos valores de rugosidade foram mantidos, demonstrando que operações de acabamento em aço ABNT H13 IM com dureza de 50 HRC é possível com vida longa de ferramenta, mesmo utilizando-se valor de 500 m/min para velocidade de corte. Além disto, a análise da influência das variáveis de processo utilizadas neste trabalho mostrou que é possível, sob algumas condições, utilizar tanto ferramentas inteiriças, quanto de pastilha intercambiável montada em corpo de metal duro em operações de acabamento
Abstract: Typically, the use of hardened tool steels, along with complex shapes typical of the parts used in the field of molds and dies, offer difficulty in machining by milling, mainly in finishing operations that demand the use of long tool. The HSM (High Speed Machining or High Speed Milling) has become a possible alternative for making this type of machining, reducing, or sometimes eliminating electric discharge machining and polishing operations. Usually, indexable carbide insert mills has been used for roughing and semi-finishing, while in finishing operations or when the machining geometries that require tools with small diameters the integral tools are used yet. The main objective of this study is to evaluate the influence of five process variables, with high cutting speed, on the finish of the machined surface. The influence of tool wear on surface finish through 400 minutes of milling was also evaluated, as well as a comparison between integral carbide mills and indexable insert mounted at cemented carbide toolholder endmills, in order to evaluate the technical feasibility of using this second type of tool, replacing the traditional integral carbide endmills used in finishing operations. In most experiments, small roughness values were maintained, showing that finishing operations on AISI H13 IM with a hardness of 50 HRC is possible with long tool life, even using the cutting speed of 500 m/min. Furthermore, the analysis of the influence of process variables used in this study showed that is possible, under some conditions, the use either integral carbide tools, or indexable insert mounted at cemented carbide toolholder endmills on finishing operations
Mestrado
Materiais e Processos de Fabricação
Mestre em Engenharia Mecânica
10
Lima, Daniel David de. "AvaliaÃÃo da remoÃÃo de metais pesados em efluentes industriais por sulfeto quÃmico e biogÃnico." Universidade Federal do CearÃ, 2013. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=10570.
Full textAbstract:
Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgicoO presente estudo teve o objetivo de avaliar a remoÃÃo de metais pesados em efluentes industriais pelo uso de sulfeto quÃmico e biogÃnico. Inicialmente, foi operado, sob condiÃÃes mesofÃlicas (27  2 ÂC), um reator anaerÃbio de manta de lodo e fluxo ascendente (VÃtil = 2,7 L; TDH = 24 h) suplementado com sulfato (em relaÃÃes DQO/SO42- de aproximadamente 10 e 5) para a produÃÃo de sulfeto biogÃnico. Posteriormente, o efluente das indÃstrias de folheaÃÃo de joias da cidade de Juazeiro do Norte, CearÃ, foi caracterizado para verificar os principais metais contidos e suas faixas de concentraÃÃes, alÃm de outros constituintes. Em seguida, analisou-se a aplicaÃÃo de planejamento experimental multivariado cujos fatores estudados foram concentraÃÃo de metal (20, 80 e 140 mg/L), concentraÃÃo de sulfeto (20, 40 e 60 mg/L) e tempo de reaÃÃo (1, 5 e 9 min), no processo de remoÃÃo dos metais cobre, zinco e nÃquel, tanto na presenÃa quanto na ausÃncia de macro e micronutrientes. Finalmente, foi verificada em experimentos univariacionais a influÃncia das condiÃÃes operacionais tempo de reaÃÃo (15 e 30 min), razÃo molar metal/sulfeto (0,5; 0,7; 1; 1,6; 1,75 e 2) e fonte de sulfeto (quÃmico e biogÃnico) na eficiÃncia de remoÃÃo dos metais pesados analisados. ApÃs a caracterizaÃÃo do efluente das indÃstrias de folheaÃÃo de joias constatou-se que os metais majoritÃrios foram cobre, nÃquel e zinco. O reator sulfetogÃnico apresentou operaÃÃo estÃvel para as relaÃÃes DQO/SO42- estudadas, com remoÃÃo de DQO superior a 70% e reduÃÃo de sulfato acima de 90%. A partir do planejamento experimental multivariado, observou-se que o fator mais significativo foi a concentraÃÃo de metal para todos os casos, sendo que, para o cobre, a concentraÃÃo de sulfeto nÃo teve efeito significativo na presenÃa de macro e micronutrientes. Por sua vez, para o nÃquel, constatou-se que todos os fatores exercem influÃncia sobre a eficiÃncia de remoÃÃo. Jà para o zinco, o tempo nÃo teve influÃncia significativa na ausÃncia de macro e micronutrientes, enquanto que na presenÃa dos mesmos tal variÃvel apresentou significÃncia. Em seguida, nos experimentos univariacionais verificou-se que o tempo de reaÃÃo nÃo influenciou a remoÃÃo de metais estudados. A fonte de sulfeto apresentou efeitos diversos assim como a relaÃÃo molar metal/sulfeto. Por exemplo, com o cobre, em razÃes molares metal/sulfeto menores que 1,6, foram obtidas as maiores diferenÃas na eficiÃncia de remoÃÃo chegando atà 70%. Jà para o zinco, sà foram observadas algumas diferenÃas para razÃes molares acima de 1,6. Finalmente, para o nÃquel, alguma diferenÃa sà foi verificada para razÃes de atà 1.
The present study aimed to assess heavy metals removal from industrial effluents by using chemical and biogenic sulfide. Initially, an upflow anaerobic sludge blanket reactor (working volume = 2.7 L, HRT = 24 h), supplemented with sulfate (COD/SO42- ratio of approximately 10 and 5), was operated under mesophilic conditions (27 Â 2 ÂC) for biogenic sulfide production. Subsequently, the effluent of jewelry plating industries from the city of Juazeiro do Norte, CearÃ, was characterized in order to verify the major metals and their concentration ranges, as well as other constituents. Then, the application of a multivariate experimental design, whose factors were metal concentration (20, 80 and 140 mg/L), sulfide concentration (20, 40 and 60 mg/L) and reaction time (1, 5 and 9 min), in the process of copper, zinc and nickel removal, both in the presence and absence of macro and micronutrients, was analyzed. Finally, in univariate experiments, the influence of the operating conditions, such as reaction time (15 and 30 min), metal/sulfide molar ratio (0.5, 0.7, 1, 1.6, 1.75 and 2) and sulfide source (chemical and biogenic), on the removal efficiency of the tested heavy metals was verified. After the characterization of the jewelry plating industries effluent, it was found that the majority metals were copper, nickel and zinc. The sulfidogenic reactor showed stable operation for the COD/SO42- ratios studied, with COD removal higher than 70% and sulfate reduction above 90%. From the multivariate experimental design, the most significant factor was metal concentration in all cases. For copper, sulfide concentration had no significant effect in the presence of macro and micronutrients. However, for nickel, all the factors have an influence on removal efficiency. And, for zinc, the time had no significant influence in the absence of macro and micronutrients, whereas, in their presence, that variable was significant. From the response surface contour plot, the optimum point, in terms of removal efficiency, obtained for nickel in the presence and absence of macro and micronutrients was [Ni2+] = 140 mg/L, [S2-] = 60 mg/L and t = 1 min. Subsequently, in the univariate experiments, it was found that the reaction time did not affect the removal of metals studied. The sulfide source had different effects as well as the metal/sulfide molar ratio. For example, for copper, at metal/sulfide molar ratios lower than 1.6, the greatest differences in removal efficiency were obtained, which reached up to 70%. However, for zinc, some differences were only observed at molar ratios above 1.6. Finally, for nickel, differences were observed for molar ratios below 1.
Books on the topic "Meta3C"
1
I, Tushinskiĭ L., ed. Coated metal: Structure and properties of metal-coating compositions. Berlin: Springer, 2002.
Find full text
2
author, Weheba Gamal S., ed. Manufacturing processes & materials. Dearborn, Michigan: Society of Manufacturing Engineers, 2015.
Find full text
3
Clair, Claiborne C., Winfrey Martin C, and Thebus Bill, eds. Metals. Buffalo Grove, IL: Schoolcraft Pub., 1992.
Find full text
4
K, Elshennawy Ahmad, and Doyle Lawrence E, eds. Manufacturing processes & materials. 4th ed. Dearborn, Mich: Society of Manufacturing Engineers, 2000.
Find full text
5
(Canada), Mineral Sciences Laboratories. An overview of the metals recycling industry in Canada. Ottawa, Ont: Mineral Sciences Laboratories, 1993.
Find full text
6
Hettig, Arndt. Einflussgrössen auf den Werkzeugbruch beim Voll-Vorwärts-Fliesspressen. Berlin: Springer-Verlag, 1990.
Find full text
7
Metals fabrication: Understanding the basics. Materials Park, Ohio: ASM International, 2013.
Find full text
8
Institution of Mining and Metallurgy (Great Britain), ed. Recycling of metalliferous materials: Papers presented at the Recycling of Metalliferous Materials Conference, organized by the Institution of Mining and Metallurgy and held in Birmingham, England, from 23 to 25 April, 1990. London, England: The Institution, 1990.
Find full text
9
Recycling of Metalliferous Materials Conference (1990 Birmingham, England). Recycling of metalliferous materials: Papers presented at the Recycling of Metalliferous Materials Conference, organized by the Institution of Mining and Metallurgy and held in Birmingham, England, from 23 to 25 April, 1990. London: Institution of Mining and Metallurgy, 1990.
Find full text
10
Architectural metal surfaces. Hoboken, N.J: John Wiley & Sons, 2005.
Find full textBook chapters on the topic "Meta3C"
1
Dunbar, W. Scott, and Jocelyn Fraser. "A Closer Relationship with Our Metals." In Heavy Metal, 127–36. Cambridge, UK: Open Book Publishers, 2024. http://dx.doi.org/10.11647/obp.0373.13.
Full textAbstract:
The existence and availability of metals is taken for granted by most people. However, these perceptions will be challenged as global metal demand increases due to economic development, and supplies are threatened by dwindling geological reserves and shifting geopolitics. Alternative sources and methods of supply must be developed if we are to meet anticipated needs for metals, including those required for the transition to renewable energy systems. The ideal goal is a circular economy, where recycling and reuse of metal-containing products keep these resources available to the economy as long as possible. At the same time, innovation within the existing global metal supply system can provide new access to metal sources and opportunities for improved recovery of metals along the supply chain. The key is to open new points of entry into the metal supply system, identify and remove barriers, introduce necessary technologies, and organize more efficient business models. This includes the targeting of smaller-scale deposits and the more efficient recovery of metals from waste material at various points along the supply chain. If society were more engaged in such developments, metals could be more efficiently supplied with significant economic benefits to a larger number of individuals.
2
Southam, Gordon. "Microbial Mining." In Heavy Metal, 211–18. Cambridge, UK: Open Book Publishers, 2024. http://dx.doi.org/10.11647/obp.0373.28.
Full textAbstract:
With the discovery of a wide range of biological processes affecting metal cycling on Earth, biotechnology is receiving increased attention from the mining industry. The diverse genetic responses of microbes to high metal concentrations metals offer a win-win opportunity, providing exploration targets and new approaches to bioremediation of metal pollution through the enhanced recovery of critical metals. This essay considers how biotechnology could be harnessed across the mining life cycle to improve the discovery and extraction of ore deposits, and the recovery and treatment of potentially hazardous wastes.
3
Prentø, P. "Metals and Metal Salts." In Theory and Strategy in Histochemistry, 223–38. Berlin, Heidelberg: Springer Berlin Heidelberg, 1991. http://dx.doi.org/10.1007/978-3-642-73742-8_17.
Full text
4
Bircher, Andreas J. "Metal Allergy: Other Metals." In Metal Allergy, 467–79. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-58503-1_35.
Full text
5
Holuszko, Maria. "A New Life for Old Metals." In Heavy Metal, 219–28. Cambridge, UK: Open Book Publishers, 2024. http://dx.doi.org/10.11647/obp.0373.29.
Full textAbstract:
The current global economy is based on the extraction of natural resources for use in products that are often disposed of after a short time. Some of the metals used in these products are becoming scarcer and more expensive, and their extraction can be associated with negative social and environmental impacts. This has prompted significant efforts to recover and recycle metals from a wide variety of post-consumer products. With a particular focus on the challenging problem of electronic waste, this essay looks at the technical, social and economic factors shaping metal re-use and recycling. Electronic waste streams can be highly enriched in metals relative to primary mined sources, and they can be considered as the richest ore deposits in the world, often containing elements that are critical for green technology applications. Failure to recover these metals not only presents a significant missed economic opportunity, but also a potential environmental threat to air, water and soil. At present, standards and practices of metal recycling and recovery are highly variable around the world, and a more coordinated effort is needed to increase their efficiency. This will require new technological approaches, alongside economic incentives and regulatory oversight. With the right intention and approaches, there is a significant opportunity to recover valuable materials from metal-rich ‘urban mines’, building robust, resilient and efficient recycling systems that are needed for a truly circular economy.
6
Chung Wai Mak, Thomas, Yu-San Cheung, Gong-Du Zhou, and Ying-Xia Wang. "Structural Chemistry of Alkali and Alkaline-Earth Metals." In Structural Chemistry across the Periodic Table, 39–72. Oxford University PressOxford, 2023. http://dx.doi.org/10.1093/oso/9780198872955.003.0002.
Full textAbstract:
Abstract This chapter covers the following topics: survey of the alkali metals, structure and bonding in inorganic alkali metal compounds, structure and bonding in organic alkali metal compounds, alkalides and electrides, survey of the alkaline-earth metals, structure of compounds of alkaline-earth metals, organometallic compounds of Group 2 elements, alkali and alkaline-earth metal complexes with inverse crown structures, as well as alkaline-earth metal hydrides.
7
V. Chopda, Lakha. "Small Organic Molecule as Corrosion Inhibitors for Mitigating Metal Corrosion." In Introduction to Corrosion - Basics and Advances [Working Title]. IntechOpen, 2023. http://dx.doi.org/10.5772/intechopen.110161.
Full textAbstract:
Metal corrosion constitutes degradation of metals in the presence of favorable corrosive atmosphere. It worsens metal quality. The prevention of metal corrosion is so significant to save metals for their better utility. Corrosion inhibitors are widely used for the mitigation of metal corrosion. Small organic molecules as corrosion inhibitors are showed prominent corrosion inhibitive property because of their unique electron donating capacity to the metal orbitals. The bonding occurred between organic molecules and metals are main aspect to retard the corrosive environment toward metal.
8
Duchin, Faye, and Glenn-Marie Lange. "Processing and Fabrication of Metals." In The Future Of The Environment, 100–119. Oxford University PressNew York, NY, 1995. http://dx.doi.org/10.1093/oso/9780195085747.003.0007.
Full textAbstract:
Abstract Representation of Metals in the World Model The World Model explicitly tracks the extraction of six nonfuel metallic ores: copper (SES), bauxite (aluminum) (SE6), nickel (SE7), zinc (SES), lead (SE9) and iron ore (SElO). There is a single sector for primary processing of metals (XXS). To retain detail about the mix of metals in refined metals, the metal fabricating sectors purchase their refined metal inputs in two parts, the ore directly from the mining sectors (SES-10) and the services for transforming ore to semimanufactured inputs from the refining sector (XX:5). The metal extraction, processing, and principal metal fabricating sectors are shown in Table 7.1.
9
Plemić, Bojana, and Jelena Anđelković Grašar. "We do need an education: youth participation programmes as a method in archaeology dissemination." In Proceedings from the 8th and 9th Scientific Conference Methodology and Archaeometry. Filozofski fakultet Sveučilišta u Zagrebu - FF Press, 2022. http://dx.doi.org/10.17234/metarh.2022.13.
Full text
10
Šošić Klindžić, Rajna. "“If its quacks like a duck” – interpretation of Late Neolithic site Gorjani Kremenjača, Eastern Croatia." In Proceedings from the 8th and 9th Scientific Conference Methodology and Archaeometry. Filozofski fakultet Sveučilišta u Zagrebu - FF Press, 2022. http://dx.doi.org/10.17234/metarh.2022.09.
Full textConference papers on the topic "Meta3C"
1
"Issledovanie neokislitelnoy konversii metana na metall-soderzhashchikh tseolitakh tipa zsm-5." In Perspektivnye materialy s ierarkhicheskoy strukturoy dlya novykh tekhnologiy i nadezhnykh konstruktsiy, Khimiya nefti i gaza. Tomsk State University, 2018. http://dx.doi.org/10.17223/9785946217408/566.
Full text
2
Dogan, Mustafa. "The Influence of Heavy Metals on the Urban Flora / UTICAJ TEŠKIH METALA NA URBANU FLORU." In Drugi međunarodni kolokvijum „BIODIVERZITET – TEORIJSKI I PRAKTIČNI ASPEKTI“ / Second International Colloqium „BIODIVERSITY – THEORETICAL AND PRACTICAL ASPECTS“. Akademija nauka i umjetnosti Bosne i Hercegovine/Academy of Sciences and Arts of Bosnia and Herzegovina, 2012. http://dx.doi.org/10.5644/proc.bd-01.16.
Full text
3
Lin, Yu-Ru, Jimeng Sun, Paul Castro, Ravi Konuru, Hari Sundaram, and Aisling Kelliher. "MetaFac." In the 15th ACM SIGKDD international conference. New York, New York, USA: ACM Press, 2009. http://dx.doi.org/10.1145/1557019.1557080.
Full text
4
Lo, Chieh, and Radu Marculescu. "MetaNN." In BCB '18: 9th ACM International Conference on Bioinformatics, Computational Biology and Health Informatics. New York, NY, USA: ACM, 2018. http://dx.doi.org/10.1145/3233547.3233696.
Full text
5
Wallis, Nicola G., Valerio Berdini, Gilbert Besong, Gianni Chessari, Joe Coyle, Brent Graham, Andrew Madin, et al. "Abstract A1: The physiological form of MetAP2 can be inhibited through binding to either of the two active‐site metals." In Abstracts: AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics--Nov 15-19, 2009; Boston, MA. American Association for Cancer Research, 2009. http://dx.doi.org/10.1158/1535-7163.targ-09-a1.
Full text
6
Ramadan, Hany E., Christopher J. Rossbach, Donald E. Porter, Owen S. Hofmann, Aditya Bhandari, and Emmett Witchel. "MetaTM/TxLinux." In the 34th annual international symposium. New York, New York, USA: ACM Press, 2007. http://dx.doi.org/10.1145/1250662.1250675.
Full text
7
Lundgaard, Stefan, Soon Hock Ng, Michael Mazilu, and Saulius Juodkazis. "Black metals." In Micro + Nano Materials, Devices, and Applications 2019, edited by M. Cather Simpson and Saulius Juodkazis. SPIE, 2019. http://dx.doi.org/10.1117/12.2541118.
Full text
8
Sunk, Werner. "Survey of Metal Recovery in the U.S. WTE Industry." In 15th Annual North American Waste-to-Energy Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/nawtec15-3219.
Full textAbstract:
Part of the WTERT effort to increase the amount of metals recovered by the U.S. Waste-to-Energy industry was a survey to determine the type of equipment used for metal recovery and the quantities of ferrous and non-ferrous metals recovered, and the distribution in percent between front- and back-end recovered metals. A questionnaire was sent to the headquarters of the three major WTE companies and fifty three WTE plants responded with data for the year 2004. As mass burn and RDF plants were examined separately, a comparison of metal recovery by means of these two technologies was possible. The ways to recover metals in the U.S. WTE industry range from only manual separation of large objects at the tipping floor at mass burn facilities, to front-end recovery at RDF plants, to metal separation from the ash at the back-end of the WTE process or at a regional metal recovery facility. Accordingly, the amounts of metals recovered range from very little to over 40.000 tons per year. Comparison of the collected with estimated averages of ferrous (5%) and non-ferrous (0.7%) metals in U.S. MSW, indicated that 48% of ferrous and 9% of non-ferrous metal input are recovered at these 53 WTE facilities every year. The remainder is landfilled and represents a revenue loss that may be as high as $160 millions per year, including the payment of tipping fees for landfilling metals. Mass burn facilities recover an average of 43% of the ferrous and 5% of the non-ferrous metals, while RDF plants recover 71% of ferrous and 30% of non-ferrous of the assumed metal input. However, the metal input in some WTEs may differ from the U.S. average because of effective metal recycling practice in the community. Analysis of the front- and back-end recovery at mass burn and RDF plants shows that the former recover only 1% of the ferrous metal at the front-end and 99% from the bottom ash. In comparison, RDF plants recover 88% of the ferrous metal at the front-end and only 12% after combustion. Mass burn plants recover 94% of the non-ferrous metal at the back end. It is interesting to note that RDF plants also recover most of their non-ferrous metals (98% of the total) at the back-end. Our analysis shows that there is room for increasing metal recovery of both ferrous and non-ferrous metals at selected mass burn facilities that presently recover less than 10% of the input ferrous metals. Non-ferrous metal recovery is very low for mass-burn and low for RDF plants. Since the value of WTE metals has increased appreciably recently, due to increased consumption in China, it is a good time to consider plant modifications that will help increase metal recovery. Some of the most likely WTEs for implementing such modifications have been identified and discussions are under way for effecting plant retrofits at some facilities. A current objective is to obtain similar data from the nearly 30 facilities that were not included in the first part of this survey. We are also trying to determine how metal recycling practice in the communities that supply various WTE facilities correlates with the metal recoveries attained by these facilities.
9
Dodd, Kevin, Joe Robinson, and Maria Lindberg. "BPEO/BPM in Recycling of Low Level Waste Metal in the UK." In ASME 2009 12th International Conference on Environmental Remediation and Radioactive Waste Management. ASMEDC, 2009. http://dx.doi.org/10.1115/icem2009-16210.
Full textAbstract:
Best Practicable Environmental Option (BPEO) and Best Practicable Means (BPM) are concepts well established in the nuclear industry to help guide and inform waste management decision making. The recycling of contaminated metal waste in the UK is not well established, with the majority of waste disposed of at the Low Level Waste Repository (LLWR) at Drigg. This paper presents an overview of the Strategic BPEO study completed by Studsvik examining the options for low level metal waste management and a subsequent BPM study completed in support of a proposed metals recycling service. The environmental benefits of recycling metals overseas is further examined through the application of lifecycle analysis to the metals recycling process. The methodologies used for both studies are discussed and the findings of these studies presented. These indicate that recycling contaminated metal is the preferred option, using overseas facilities until UK facilities are available. The BPM for metals recycling is discussed in detail and indicates that a tool box for processing metal waste is required to ensure BPM is applied on a case by case basis. This is supported by effective management of waste transport and waste acceptance criteria. Whilst the transport of contaminated metal overseas for treatment adds to the environmental burden of metals recycling, this when compared with the production of virgin metal, is shown to remain beneficial. The results of the Studsvik studies demonstrate the benefits of recycling metals, the options available for such a service and challenges that remain.
10
Bingham, Richard G. "The next steps." In Metal Mirrors, edited by Richard G. Bingham and David D. Walker. SPIE, 1993. http://dx.doi.org/10.1117/12.158739.
Full textReports on the topic "Meta3C"
1
Johnson. L51924 Evaluation of Welding Consumables and Processes for X100 Steel. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), October 2003. http://dx.doi.org/10.55274/r0010348.
Full textAbstract:
The primary objective of this study was to evaluate the mechanical properties of weld metals deposited using a number of commercially available welding consumables and welding processes. The secondary objectives of this work included characterizing weld metal microstructure, assessing hydrogen-assisted cracking susceptibility of the weld metal and X100 base metal, and solidification cracking susceptibility of selected welding consumables.
2
Busby, Ryan, Thomas Douglas, Joshua LeMonte, David Ringelberg, and Karl Indest. Metal accumulation capacity in indigenous Alaska vegetation growing on military training lands. Engineer Research and Development Center (U.S.), August 2021. http://dx.doi.org/10.21079/11681/41443.
Full textAbstract:
Permafrost thawing could increase soil contaminant mobilization in the environment. Our objective was to quantify metal accumulation capacities for plant species and functional groups common to Alaskan military training ranges where elevated soil metal concentrations were likely to occur. Plant species across multiple military training range sites were collected. Metal content in shoots and roots was compared to soil metal concentrations to calculate bioconcentration and translocation factors. On average, grasses accumulated greater concentrations of Cr, Cu, Ni, Pb, Sb, and Zn relative to forbs or shrubs, and bioconcentrated greater concentrations of Ni and Pb. Shrubs bioconcentrated greater concentrations of Sb. Translocation to shoots was greatest among the forbs. Three native plants were identified as candidate species for use in metal phytostabilization applications. Elymus macrourus, a grass, bioconcentrated substantial concentrations of Cu, Pb, and Zn in roots with low translocation to shoots. Elaeagnus commutata, a shrub, bioconcentrated the greatest amounts of Sb, Ni, and Cr, with a low translocation factor. Solidago decumbens bio-concentrated the greatest amount of Sb among the forbs and translocated the least amount of metals. A combination of forb, shrub, and grass will likely enhance phytostabilization of heavy metals in interior Alaska soils through increased functional group diversity.
3
Wilkowski. L51487 Predict the Interaction of Fracture Toughness and Constraint Effects for Surface Cracked Pipe. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), April 1985. http://dx.doi.org/10.55274/r0010596.
Full textAbstract:
This report summarizes a program designed to quantify the disagreement between the standard t x 2t bend specimen and surface-cracked pipe data. The effect of untracked ligament length on upper-shelf toughness was also investigated. Ultimately, the findings will have application to pipeline girth welds. But in this first step, unwelded line-pipe steel specimens were used throughout this investigation. Obviously, weld metal specimen data would be more directly applicable to welded pipe. However, weld metal test data exhibit more scatter than base metal data (largely due to material non-homogeneity). This scatter could cloud the general data trends under investigation. Consequently, base metal specimens were used to more clearly establish these trends. This will form a basis for further investigations on weld metals.
4
Clausen, Jay, Samuel Beal, Thomas Georgian, Kevin Gardner, Thomas Douglas, and Ashley Mossell. Effects of milling on the metals analysis of soil samples containing metallic residues. Engineer Research and Development Center (U.S.), July 2021. http://dx.doi.org/10.21079/11681/41241.
Full textAbstract:
Metallic residues are distributed heterogeneously onto small-arms range soils from projectile fragmentation upon impact with a target or berm backstop. Incremental Sampling Methodology (ISM) can address the spatially heterogeneous contamination of surface soils on small-arms ranges, but representative kilogram-sized ISM subsamples are affected by the range of metallic residue particle sizes in the sample. This study compares the precision and concentrations of metals in a small-arms range soil sample processed by a puck mill, ring and puck mill, ball mill, and mortar and pestle prior to analysis. The ball mill, puck mill, and puck and ring mill produced acceptable relative standard deviations of less than 15% for the anthropogenic metals of interest (Lead (Pb), Antimony (Sb), Copper (Cu), and Zinc (Zn)), with the ball mill exhibiting the greatest precision for Pb, Cu, and Zn. Precision by mortar and pestle, without milling, was considerably higher (40% to >100%) for anthropogenic metals. Media anthropogenic metal concentrations varied by more than 40% between milling methods, with the greatest concentrations produced by the puck mill, followed by the puck and ring mill and then the ball mill. Metal concentrations were also dependent on milling time, with concentrations stabilizing for the puck mill by 300 s but still increasing for the ball mill over 20 h. Differences in metal concentrations were not directly related to the surface area of the milled sample. Overall, the tested milling methods were successful in producing reproducible data for soils containing metallic residues. However, the effects of milling type and time on concentrations require consideration in environmental investigations.
5
Calhoun, C. L. Jr, L. E. Nulf, and A. H. Gorin. Sulfur polymer cement encapsulation of RCRA toxic metals and metal oxides. Office of Scientific and Technical Information (OSTI), June 1995. http://dx.doi.org/10.2172/161467.
Full text
6
Franzen, H. F. The metal-rich sulfides and phosphides of the early transition metals. Office of Scientific and Technical Information (OSTI), June 1996. http://dx.doi.org/10.2172/244545.
Full text
7
Mihalczo, John T. Historic Measurement with up to 3 Metric Tons of Weapons Grade HEU Metal. Office of Scientific and Technical Information (OSTI), November 2018. http://dx.doi.org/10.2172/1485137.
Full text
8
Long, Wendy, Zackery McClelland, Dylan Scott, and C. Crane. State-of-practice on the mechanical properties of metals for armor-plating. Engineer Research and Development Center (U.S.), January 2023. http://dx.doi.org/10.21079/11681/46382.
Full textAbstract:
This report presents a review of quasi-static and dynamic properties of various iron, titanium, nickel, cobalt, and aluminum metals. The physical and mechanical properties of these materials are crucial for developing composite armoring systems vital for protecting critical bridges from terrorist attacks. When the wide range of properties these materials encompass is considered, it is possible to exploit the optimal properties of metal alloys though proper placement within the armoring system, governed by desired protective mechanism and environmental exposure conditions.
9
Melton and Bertaso. L52016 Active Flux GTAW Welding Process for Carbon Steel Line Pipe Applications - Phase 1. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), September 2003. http://dx.doi.org/10.55274/r0010376.
Full textAbstract:
The Gas Tungsten Arc Welding (GTAW) process has been used for many years in the joining of carbon steel, alloy steel and non-ferrous alloys. Its capacity to deposit an external root, the ability to choose filler metals for a wide variety of base metals, and its favorable deposition characteristics make this a versatile process which is associated with low defect susceptibility, and excellent weld metal properties. Unfortunately, the GTAW process has not historically been associated with high productivity rates. Past efforts to enhance productivity through "hot wire" technology have improved the GTAW process markedly. Nevertheless, even with "hot wire"technology, the establishment of a GTAW root pass has not been considered competitive with existing GMAW mechanized processes. The objective of this project is to optimize the productivity of the GTAW process for girth welding of pipelines using activating fluxes.
10
Graville. L51764 Hydrogen Cracking in the Heat-Affected Zone of High-Strength Steels-Year 2. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), March 1997. http://dx.doi.org/10.55274/r0010170.
Full textAbstract:
During year 1 of this project a test to evaluate the sensitivity of the heat affected zone (HAZ) to hydrogen cracking was developed. This was in response to a need for a test which provided unambiguous results in contrast to existing test methods which often led to difficulties in interpretation. For example, WIC tests usually cracked in the weld metal rather than the HAZ and therefore did not produce a clear indication of the sensistivity of the HAZ. The new test involves a machined notch which can be placed in the HAZ thus forcing crack initiation to occur in the desired region. A further advantage of the new test is that it is quantitative with each test specimen providing a measure of the sensitivity of the HAZ in that test. Existing tests are usually of the crack/no-crack type requiring a series of tests at different preheats to be carried out in order to establish a critical value. This is an expensive, time-consuming approach. The new test measures the deflection to first load drop (normally the onset of significant cracking) when the welded specimen is loaded in bending. It was also shown during the first year of the project that the simple geometry of the test lends itself to easy analysis enabling the stress/strain distribution to be calculated by finite element analysis. The quantitative measurement of susceptibility in the test enabled the cracking of more complex welds to be predicted on the basis of a local critical hydrogen model. The objective of the work was to extend the notched bend test to the evaluation of weld metal sensitivity to hydrogen cracking. The experiments were designed to determine whether the test could discriminate between two different weld metals and to study the effects of reducing hydrogen content. In addition, finite element analysis of the weld metal test was carried out and finite difference analysis used to predict the local hydrogen concentration. This work modifies the notched bend test, developed for evaluating the sensitivity of the heat affected zone (HAZ), to allow the evaluation of weld metal. The results showed that weld metal could readily be evaluated, with the test discriminating among weld metals of different composition and hydrogen contact. Finite element analysis was undertaken and showed that for the two weld metals tested, cracking occurred at the same local stress when the hydrogen content was the same, despite differences in strength. A finite model was used to calculate the distribution of hydrogen as a function of aging time. Although the general trends were confirmed by the experimental measurements of hydrogen content, there was considerable scatter attributed to the small hydrogen volumes measured.