Articles de revues : « Carbon Dits »

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Suvanam, Sethu Saveda, David M. Martin, Carl Mikael Zetterling et Anders Hallén. « Tailoring the Interface between Dielectric and 4H-SiC by Ion Implantation ». Materials Science Forum 821-823 (juin 2015) : 488–91. http://dx.doi.org/10.4028/www.scientific.net/msf.821-823.488.

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In this paper effects of carbon (C), silicon (Si) and nitrogen (N) implantation on the interface properties of 4H-SiC/SiO2and the implications for 4H-SiC bipolar junction transistors (BJT) passivation are discussed. 4H-SiC epi-layer have been implanted with12C,14N and28Si ion at three different doses with energies of 3, 3.5 and 6 keV, respectively, resulting in a projected range of 8 nm for the three ions. Then metal oxide semiconductor (MOS) structures with SiO2as dielectric have been fabricated. Capacitance voltage measurements show an increase in the negative fixed charges for all the implanted samples as a function of implantation induced damage. Similarly, in the case of C and Si, the surface roughness increases as a function of dose and the mass of the ions. No reduction of Dits due to the implantations is seen for any of the ions. Furthermore, TCAD device simulations of npn bipolar junction transistors (BJT), using the interface and fixed charges extracted from CV measurements, show a way to further optimize current gain and breakdown properties for the BJT.

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Azuma, Hideto. « A New Structural Model for Nongraphitic Carbons ». Journal of Applied Crystallography 31, n^o 6 (1 décembre 1998) : 910–16. http://dx.doi.org/10.1107/s0021889898008085.

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A structural analysis using a new, simple model describing the stacking structure of nongraphitic carbons is presented. The model is based on the idea that there is only a nearest-neighbour interaction between carbon layers. The nearest-neighbour interaction is described by the distribution of interlayer dist-ances, which, assuming a linear conjugate of two independent Gaussian distributions, gives a good fit to the obtained X-ray diffraction profile of carbon. This model is applied to a heat-treated series of nongraphitizing carbons from phenolic resin. The result shows that the average interlayer distances are about 0.4 nm. The model allows the diffraction intensity from carbon layers and the scattering intensity due to the porous structure of the carbon samples to be differentiated.

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Pelícia, Vanessa Cristina, Kelen Cristiane Zavarize, Carlos Ducatti, Ana Cristina Stradiotti, Antonio Celso Pezzato, Priscila Cavalca de Araujo, Mariela Akie Okino Mituo, Luciene Aparecida Madeira et José Roberto Sartori. « Nucleotídeos na dieta de frangos de corte e seus efeitos sobre taxa de turnover da mucosa intestinal antes e após lesões causadas por coccidiose ». Ciência Rural 41, n^o 9 (septembre 2011) : 1652–59. http://dx.doi.org/10.1590/s0103-84782011000900027.

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O objetivo deste trabalho foi avaliar o efeito da dieta suplementada com nucleotídeos sobre taxa de turnover da mucosa intestinal de frangos antes e após lesões causadas por coccidiose por meio de análise isotópica, utilizando a variação do carbono-13 em plantas C3 e C4. Foram utilizados 264 pintos submetidos a dois tratamentos: dieta controle e dieta suplementada com 0,07% nucleotídeos. Os pintos possuíam sinais isotópicos em seus tecidos semelhantes ao de ditas C4. Após o alojamento, para avaliar taxa de turnover da mucosa, as aves receberam dietas predominantemente C3. Com 16 dias de idade, 50% das aves de cada tratamento foram inoculadas com oocistos de Eimeria acervulina e, a partir de 21 dias, para avaliar a taxa de turnover após desafio, as aves passaram a receber dieta predominantemente C4. Amostras de mucosa foram analisadas isotopicamente por espectrometria de massa. Na fase inicial, a suplementação com nucleotídeos propiciou aceleração na troca do carbono na mucosa, com meia-vida de 1,06 e 1,01 dias para dieta controle e com nucleotídeos, respectivamente, acelerando o crescimento intestinal. Na fase de 21 a 42 dias de idade, para os grupos não desafiados com coccidiose, as meias-vidas do carbono foram 1,81 e 1,80 dias para dieta controle e com nucleotídeos, respectivamente, não havendo influência dos tratamentos. Porém, nos grupos desafiados, as meias-vidas foram 1,01 dias no grupo controle e 0,75 dias no que recebeu dieta com nucleotídeos, indicando maior turnover da mucosa nesse último grupo. A adição de nucleotídeos promove aceleração no processo de renovação da mucosa intestinal e na regeneração após danos causados por coccidiose.

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Hilding, Jenny, Eric A. Grulke, Z. George Zhang et Fran Lockwood. « Dispersion of Carbon Nanotubes in Liquids ». Journal of Dispersion Science and Technology 24, n^o 1 (2 janvier 2003) : 1–41. http://dx.doi.org/10.1081/dis-120017941.

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Albernaz, Danilo Fernandes, et Risely Ferraz-Almeida. « English PERFORMANCE AND EFFICIENCY OF GLASS AND CARBON FIBER BARS FOR SELF-PROPELLED SPRAYERS ». ENERGIA NA AGRICULTURA 35, n^o 3 (29 septembre 2020) : 330–38. http://dx.doi.org/10.17224/energagric.2020v35n3p330-338.

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PERFORMANCE AND EFFICIENCY OF GLASS AND CARBON FIBER BARS FOR SELF-PROPELLED SPRAYERS DANILO FERNANDES ALBERNAZ1, RISELY FERRAZ-ALMEIDA1 1Luiz de Queiros College of Agriculture, Departament of Soil Sciente, University of São Paulo, Avenida Pauda Dias, 11, 13418-900, Piracicaba, São Paulo, Brazil, albernazdanilof@hotmail.com; rizely@gmail.com ABSTRACT: Agribusiness has a fundamental role in the Brazilian economy, responsible for stimulating the Gross Domestic Product, creating investment and development opportunities. High yields have been faced in pest-free areas in different crop regions. However, pest control with high efficiency is a challenge for many farmers. In this context, self-propelled sprayers with a high efficiency are necessary to increase the quality and speed of application with a direct decreasing equipment's operational cost. This work aims: (i) present the advantages of using carbon fiber booms in the performance of self-propelled sprayers; (ii) compare weight and fuel consumption of self-propelled sprayers with carbon fiber booms and conventional carbon steel booms. The results showed that the self-propelled sprayers with glass/carbon fiber boom presented better application performances, considered 6% more productive, 1.8% lighter, and 44% more economical in fuel consumption than the conventional carbon steel boom. Based on the results, the self-propelled glass/carbon fiber boom is a better alternative to increase agricultural spraying productivity. Keywords: efficiency of the application, carbon fiber, composite, fuel consumption. DESEMPENHO E EFICIÊNCIA DE BARRAS DE VIDRO E FIBRA DE CARBONO PARA PULVERIZADORES AUTO-PROPELIDO RESUMO: O agronegócio tem papel fundamental na economia brasileira com significante participação no Produto Interno Bruto, criando oportunidades de investimento e desenvolvimento no Brasil. Em todas as culturas, altas produtividades estão associadas a áreas livres de pragas, no entanto, o controle de pragas é um desafio para muitos agricultores. Nesse contexto, a escolha de pulverizadores eficientes para aplicação de pesticidas torna-se uma necessidade para aumentar a qualidade e velocidade da aplicação, e diminuir o custo operacional deste equipamento. Este trabalho tem como objetivos: (i) apresentar as vantagens do uso de barras de fibra de carbono no desempenho de pulverizadores; (ii) comparar o peso e o consumo de combustível de pulverizadores com barras de fibra de carbono, e pulverizadores com barras convencionais de aço carbono. Os resultados mostraram que os pulverizadores com barra de fibra de vidro/carbono apresentaram melhores desempenhos de aplicação, considerado 6% mais produtivo, 1,8% mais leve, e 44% mais econômico em consumo de combustível em comparação com a barra de aço carbono convencional. Portanto, pode-se concluir que para otimizar a pulverização de culturas agrícolas, a barra de fibra de vidro/carbono é uma alternativa mais eficiente para aumentar a produtividade na pulverização agrícola. Palavras-chaves: eficiência de aplicação, fibra de carbono, composto, consumo de combustível.

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Dixon, Kiera A., Malia K. Michelsen et Catherine L. Carpenter. « Modern Diets and the Health of Our Planet : An Investigation into the Environmental Impacts of Food Choices ». Nutrients 15, n^o 3 (30 janvier 2023) : 692. http://dx.doi.org/10.3390/nu15030692.

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Popular modern diets are often seen as a panacea for improving health and promoting weight reduction. While there is a large body of literature reporting the health benefits of popular diets, few studies have described their planetary benefits. Our investigation aims to evaluate the simultaneous impacts of six popular diets within the United States on both human and planetary health. Using carbon footprint databases and representative meal plans, the environmental and health-related impacts of the Standard American, Mediterranean, vegan, paleo, keto, and climatarian diets are compared using the currently available literature. Results indicate that diets that exhibit lower carbon footprints also have positive effects on human health. The diets found to have the lowest environmental impacts were the vegan, climatarian, and Mediterranean diets. These low-carbon-footprint diets can likely be attributed to a reduced reliance on ruminant meat (cattle and sheep) and processed food consumption, while diets with high carbon footprints are more dependent on ruminant meat and saturated fat. Moderate consumption of meats such as chicken, pork, and fish in conjunction with an emphasis on locally grown fruits and vegetables can be maintained without adversely affecting the planetary carbon footprint and with the added benefit of promoting good health. Thus, making simple substitutions within each individual’s diet can be advertised as an effective approach to collectively lower the environmental impact in tandem with improving health and longevity.

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Febvay, G., Y. Rahbe, M. Rynkiewicz, J. Guillaud et G. Bonnot. « Fate of dietary sucrose and neosynthesis of amino acids in the pea aphid, acyrthosiphon pisum, reared on different diets ». Journal of Experimental Biology 202, n^o 19 (1 octobre 1999) : 2639–52. http://dx.doi.org/10.1242/jeb.202.19.2639.

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The fate of sucrose, the major nutrient of an aphid's natural food, was explored by radiolabeling in the pea aphid Acyrthosiphon pisum. To investigate the influence of nitrogen quality of food on amino acid neosynthesis, pea aphids were reared on two artificial diets differing in their amino acid composition. The first (diet A) had an equilibrated amino acid balance, similar to that derived from analysis of aphid carcass, and the other (diet B) had an unbalanced amino acid composition similar to that of legume phloem sap. Aphids grown on either diet expired the same quantity of sucrose carbon as CO(2), amounting to 25–30 % of the ingested sucrose catabolized in oxidation pathways. On diet A, the aphids excreted through honeydew about twice as much sucrose carbon as on diet B (amounting to 12.6 % of the ingested sucrose for diet A and 8.4 % for diet B), while amounts of sucrose carbons incorporated into exuviae were almost identical (1.9 % of the ingested sucrose on diet A and 2.7 % on diet B). There was also no difference in the amounts of sucrose carbon incorporated into the aphid tissues, which represented close to 50 % of the ingested sucrose. Sucrose carbons in the aphid tissues were mainly incorporated into lipids and the quantities involved were the same in aphids reared on either diet. On diet B, we observed neosynthesis of all protein amino acids from sucrose carbons and, for the first time in an aphid, we directly demonstrated the synthesis of the essential amino acids leucine, valine and phenylalanine. Amino acid neosynthesis from sucrose was significantly higher on diet B (11.5 % of ingested sucrose carbons) than on diet A (5.4 %). On diet A, neosynthesis of most of the amino acids was significantly diminished, and synthesis of two of them (histidine and arginine) was completely suppressed. The origin of amino acids egested through honeydew was determined from the specific activity of the free amino acid pool in the aphid. Aphids are able to adjust to variation in dietary amino acids by independent egestion of each amino acid. While more than 80 % of excreted nitrogen was from food amino acids, different amino acids were excreted in honeydew of aphids reared on the two diets. The conversion yields of dietary sucrose into aphid amino acids determined in this study were combined with those obtained previously by studying the fate of amino acids in pea aphids reared on diet A. The origin of all the amino acid carbons in aphid tissues was thus computed, and the metabolic abilities of aphid are discussed from an adaptive point of view, with respect to their symbiotic status.

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Sun, Xiangcheng. « Microstructure and Magnetic Properties of Carbon‐Coated Nanoparticles ». Journal of Dispersion Science and Technology 24, n^o 3-4 (7 janvier 2003) : 557–67. http://dx.doi.org/10.1081/dis-120021812.

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Gupta, Sachin D., et Sunil S. Bhagwat. « Adsorption of Surfactants on Carbon Black‐Water Interface ». Journal of Dispersion Science and Technology 26, n^o 1 (janvier 2005) : 111–20. http://dx.doi.org/10.1081/dis-200042721.

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Galvão, Franklin, Cátia Regina Augustin, Gustavo Ribas Curcio, Nelson Cosmo, Carina Kozera, Bruno Polli Domanowski et Alison Tadeu Sawczuk. « IMPACTO DE Guadua paraguayana SOBRE REMANESCENTE DE FLORESTA OMBRÓFILA MISTA ALUVIAL – UMA ABORDAGEM BIOGEOQUÍMICA ». FLORESTA 42, n^o 2 (14 mai 2012) : 355. http://dx.doi.org/10.5380/rf.v42i2.19847.

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Guadua paraguayana Döll, um bambu nativo da porção meridional da América do Sul particularmente agressivo, está invadindo áreas de preservação permanente no segundo planalto paranaense, com supressão da vegetação instalada e modificações nos padrões de sucessão local. Após estabelecer sua autoecologia, para melhor avaliar seu impacto sobre um dos últimos remanescentes da Floresta Ombrófila Mista Aluvial (FOMA), principalmente na ciclagem de nutrientes e no fluxo de carbono orgânico para o ambiente, estudou-se a composição química da espécie, a produção e decomposição de serapilheira e a distribuição das raízes. A área em estudo (25º 13’20,8” S e 50º04’26,8” W, Ponta Grossa/PR) é uma planície de inundação degradada às margens do rio Tibagi. Os valores anuais de produção de serapilheira de G. paraguayana foram estimados em 7.500 kg/ha, com meia vida superior a 260 dias para os limbos e 360 dias para as bainhas foliares. No período analisado, as folhas retornaram ao ambiente 164,27 kg/ha de macronutrientes. Com base na concentração de carbono da folha, o fluxo de carbono orgânico da vegetação para o solo foi estimado em 2.800 kg/ha/ano. Em comparação com os valores de FOMA melhor preservada, a presença dominante desse bambu reduz a quantidade de nutrientes e de carbono devolvidos ao meio.Palavras-chave: Bambu; serapilheira; ciclagem de nutrientes. AbstractGuadua paraguayana’s impacts on a remaining of Subtropical Ombrophilous Alluvial Forest – a biogeochemistry approach. Guadua paraguayana Döll, a particularly aggressive native bamboo from the southern portion of South America, is invading permanent preservation areas located in the second plateau of Parana, causing suppression of the current vegetation and modifications in the local succession patterns. After determine its autecology, to better assess its impact on one of the last remaining of Subtropical Ombrophilous Alluvial Forest, mainly on nutrient cycling and organic carbon flux to the environment, it was studied the species’ chemical composition and the production and decomposition of litter, and roots distribution. The focused area (25º13’20.8” S and 50º04’26.8” W, Ponta Grossa-PR, BR) is a degraded floodplain of Tibagi river. The annual litter production values of G. paraguayana were estimated at 7,500kg/ha, with a half-life of more than 260 days for the bladesand 360 days for the sheaths. Within this period, the photosynthetic leaves returned to the environment (bars) 164.27kg/ha of macronutrients. Based on the concentration of carbon in the leaf, the flux of organic carbon from vegetation to soil was estimated at 2,800kg/ha/year. The dominant presence of bamboo in the area decreases the amount of carbon and nutrients returned to the environment, when confronted with Subtropical Ombrophilous Alluvial Forest better preserved. Keywords: Bamboo; litter; nutrient cycling.

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Omont, A., et H. F. Bettinger. « Correlation between UV resilience and wavelength of narrow diffuse interstellar bands ». Astronomy & ; Astrophysics 637 (mai 2020) : A74. http://dx.doi.org/10.1051/0004-6361/201937071.

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Carriers of diffuse interstellar bands (DIBs) still need to be identified. In a recent paper, we reported a correlation between the DIB wavelength and the apparent UV resilience (or boost) of their carriers. We proposed that this might be an indication of the important role of conjugated elongated molecules among the DIB carriers. The aim of this paper is to further understand the origin of this correlation. The analysis of 509 optical DIBs on the lines of sight of HD 183143 and/or HD 204827 reported in the literature shows that this correlation mainly implies the 386 narrow DIBs with a band width <1.1 Å, which include most of the identified DIBs of the C2 and ζ families, while the majority of the 123 broader DIBs, including the identified σ DIBs, do not display such a correlation. We present a possible origin of this correlation from very strong bands of large conjugated elongated molecules, such as carbon chains, polyacenes, or other catacondensed polycyclic aromatic hydrocarbons. The total amount of carbon contained in all the carriers of these narrow DIBs is a very small fraction of the interstellar carbon if their oscillator strengths are ≥1. The amount of carbon locked in the carriers of the broader DIBs is higher, especially if their oscillator strengths are significantly weaker.

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Bruno, Morena, Marianne Thomsen, Federico Maria Pulselli, Nicoletta Patrizi, Michele Marini et Dario Caro. « The carbon footprint of Danish diets ». Climatic Change 156, n^o 4 (1 août 2019) : 489–507. http://dx.doi.org/10.1007/s10584-019-02508-4.

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Yang, Xiaoke, Zhihang Zhang, Huangyixin Chen, Rongrong Zhao, Zhongyue Xu, Anguo Xie et Qiuhua Chen. « Assessing the Carbon Emission Driven by the Consumption of Carbohydrate-Rich Foods : The Case of China ». Sustainability 11, n^o 7 (28 mars 2019) : 1875. http://dx.doi.org/10.3390/su11071875.

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Background: Carbohydrate-rich (CR) foods are essential parts of the Chinese diet. However, CR foods are often given less attention than animal-based foods. The objectives of this study were to analyze the carbon emissions caused by CR foods and to generate sustainable diets with low climate impact and adequate nutrients. Methods: Twelve common CR food consumption records from 4857 individuals were analyzed using K-means clustering algorithms. Furthermore, linear programming was used to generate optimized diets. Results: Total carbon emissions by CR foods was 683.38g CO2eq per day per capita, accounting for an annual total of 341.9Mt CO2eq. All individuals were ultimately divided into eight clusters, and none of the popular clusters were low carbon or nutrient sufficient. Optimized diets could reduce about 40% of carbon emissions compared to the average current diet. However, significant structural differences exist between the current diet and optimized diets. Conclusions: To reduce carbon emissions from the food chain, CR foods should be a research focus. Current Chinese diets need a big change to achieve positive environmental and health goals. The reduction of rice and wheat-based foods and an increase of bean foods were the focus of structural dietary change in CR food consumption.

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Weiner, Bruce B., Walther W. Tscharnuter et William Bernt. « Characterizing ASTM Carbon Black Reference Materials Using a Disc Centrifuge Photosedimentometer ». Journal of Dispersion Science and Technology 23, n^o 5 (11 janvier 2002) : 671–78. http://dx.doi.org/10.1081/dis-120015370.

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Zhong, Guo-Chao, Qu-Jin Li, Peng-Fei Yang, Yun-Bing Wang, Fa-Bao Hao, Kang Wang, Jie-Jun Hu et Jing-Jing Wu. « Low-carbohydrate diets and the risk of pancreatic cancer : a large prospective cohort study ». Carcinogenesis 42, n^o 5 (22 janvier 2021) : 724–32. http://dx.doi.org/10.1093/carcin/bgab006.

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Abstract Low-carbohydrate diets have become a popular approach for weight loss in recent years. However, whether low-carbohydrate diets are associated with the risk of pancreatic cancer remains to be elucidated. Hence, we examined the association of low-carbohydrate diets with the risk of pancreatic cancer in a US population. A population-based cohort of 95 962 individuals was identified. A low-carbohydrate-diet score was calculated to quantify adherence to this dietary pattern, with higher scores indicating greater adherence. Cox regression was used to calculate risk estimate for the association of the low-carbohydrate-diet score with the risk of pancreatic cancer. Subgroup analysis was used to identify the potential effect modifiers. After an average follow-up of 8.87 years (875856.9 person-years), we documented a total of 351 pancreatic cancer cases. In the fully adjusted model, the highest versus the lowest quartiles of the overall low-carbohydrate-diet score were found to be associated with a reduced risk of pancreatic cancer (hazard ratioquartile 4 versus 1: 0.61; 95% confidence interval: 0.45, 0.82; Ptrend < 0.001). Subgroup analysis found that the inverse association of low-carbohydrate diets with the risk of pancreatic cancer was more pronounced in individuals aged ≥65 years than in those aged <65 years (Pinteraction = 0.015). Similar results were obtained for animal and vegetable low-carbohydrate-diet scores. In conclusion, low-carbohydrate diets, regardless of the type of protein and fat, are associated with a lower risk of pancreatic cancer in the US population, suggesting that adherence to low-carbohydrate diets may be beneficial for pancreatic cancer prevention. Future studies should validate our findings in other populations.

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Narkis, Nava, et Svetlana Yusim. « Advanced Treatment of Effluents by Simultaneous Powdered Activated Carbon Adsorption and Flocculation ». Journal of Dispersion Science and Technology 25, n^o 5 (janvier 2005) : 695–702. http://dx.doi.org/10.1081/dis-200027330.

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Kang, Shi‐Zhao, Ze‐Yi Cui, Ling‐Yun Liu et Jin Mu. « Sensitizing Effect of Oxazine on the Photoluminescence of Cyclodextrin‐Modified Carbon Nanotubes ». Journal of Dispersion Science and Technology 27, n^o 1 (1 juin 2006) : 45–47. http://dx.doi.org/10.1081/dis-200066711.

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Sherne, V. S., А. Y. Lavrentyev et N. V. Danilova. « ACTIVE CARBON FEED ADDITIVE IN PIGLET DIETS ». Niva Povolzhya, n^o 3 (2022) : 2002. http://dx.doi.org/10.36461/np.2022.63.3.009.

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Iskandar, Ahmad, Mochammad Johansyah et Rohmat Slamet. « ANALISIS KARAKTERISTIK BAJA DC 53 PADA DIES HOT CUT MESIN EXTRUDER TWIN SCREW ». Motor Bakar : Jurnal Teknik Mesin 5, n^o 2 (11 octobre 2021) : 22. http://dx.doi.org/10.31000/mbjtm.v5i2.6225.

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Dalam dunia industri manufacture, mesin extruder banyak digunakan untuk memproduksi kebutuhan rumah tanggga yang berbahan plastik. Dies adalah salah satu komponen di dalam mesin extruder twin screw yang berfungsi sebagai cetakan/alur keluar bahan plastik. Bahan material dalam pembuatan dies harus mempunyai sifat yang keras, ulet, tahan terhadap gesekan. Salah satu bahan yang mempunyai sifat itu ialah baja DC 53. Untuk mendapatkan performa dies berbahan baja DC 53, perlu dilakukan perlakuan panas. Hasil pengujian karakteristik kekerasan material dihasilkan kekerasan rata rata 23.0 HRC dan hasil kekerasan rata rata 63,3 HRC setelah heat treatment. Hasil pengujian komposisi kimia dihasilkan, kadar carbon yang terkandung di dalam dies sebesar 1,40%, dengan hasil tersebut dies masuk dalam kelompok high carbon steel. Pengujian pemakaian di lapangan dies hot cut mampu menurunkan down time sebesar 220 menit (3,26 jam) selama dua bulan beroperasi terhadap dies import. Untuk kapasitas dies hot cut mampu menekan angka reject sebesar 327 kg, dan performa terhadap ketahanan gesekan, dies hot cut mampu menurunkan angka penggantian cutting sebanyak 109 kali. Secara keseluruhan dies hot cut treatment mampu menurunkan down time, reject, penggantian cutting terhadap dies hot cut import yang selama ini bermasalah.

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Grant, Jonathan, et Peter J. Cranford. « Carbon and Nitrogen Scope for Growth as A Function of Diet in the Sea Scallop Placopecten Magellanicus ». Journal of the Marine Biological Association of the United Kingdom 71, n^o 2 (mai 1991) : 437–50. http://dx.doi.org/10.1017/s0025315400051699.

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Laboratory feeding experiments with the sea scallop Placopecten magellanicus were carried out to compare scope for growth (SFG) to measured growth and determine the effect of diet on carbon and nitrogen SFG. Diets consisting of cultured phytoplankton, kelp detritus, and resuspended sediment were provided daily for 52 days (October-December). Measurements of clearance rate, absorption efficiency, respiration, O/N ratio, and carbon and nitrogen content of diets and scallop tissue were used to construct carbon and nitrogenbudgets for each diet. Growth coefficients were calculated from change in tissue weight during the study period.

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Kharitonov, V. A., et M. Yu Usanov. « Choice of a method of carbon wire drawing ». Ferrous Metallurgy. Bulletin of Scientific , Technical and Economic Information 77, n^o 11 (12 novembre 2021) : 1177–85. http://dx.doi.org/10.32339/0135-5910-2021-11-1177-1185.

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At present for wire production various methods of drawing are used. To choose an effective drawing method or their combination, a methodology is needed to estimate existing and new methods of drawing. A methodology of simultaneous estimation of strain-stress state of carbon wire in the area of deformation and force conditions of drawing presented. Based on it an analysis of drawing in monolith dies, roller dies of radial-shear broach, classic two- and multi-roller dies was carried out. A module-combined method of drawing was also considered. Recommended modes of reduction for drawing in monolith dies presented. It was shown that to obtain a wire of 4.0 mm diameter max, the drawing in monolith dies is most effective. For production of wire of larger diameters, roller dies are more advisable. Application of the technology of radial-shear deformation enables to obtain a fine-grained structure in the surface layers of wire. It was shown that application of a module comprising a roller die and a monolith die is most effective. An example of drawing of a round wire from 8.0 mm diameter to 3.0 mm diameter by a route developed with their application considered. Recommendations on application of various methods of drawing for wires of diameter from 0.007 mm to 15.0 mm presented.

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Sponheimer, Matt, Todd Robinson, Linda Ayliffe, Ben Passey, Beverly Roeder, Lisa Shipley, Elvia Lopez, Thure Cerling, Denise Dearing et Jim Ehleringer. « An experimental study of carbon-isotope fractionation between diet, hair, and feces of mammalian herbivores ». Canadian Journal of Zoology 81, n^o 5 (1 mai 2003) : 871–76. http://dx.doi.org/10.1139/z03-066.

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The carbon-isotope composition of hair and feces offers a glimpse into the diets of mammalian herbivores. It is particularly useful for determining the relative consumption of browse and graze in tropical environments, as these foods have strongly divergent carbon-isotope compositions. Fecal δ13C values reflect the last few days consumption, whereas hair provides longer term dietary information. Previous studies have shown, however, that some fractionation occurs between dietary δ13C values and those of hair and feces. Accurate dietary reconstruction requires an understanding of these fractionations, but few controlled-feeding studies have been undertaken to investigate these fractionations in any mammalian taxa, fewer still in large mammalian herbivores. Here, we present data from the first study of carbon-isotope fractionation between diet, hair, and feces in multiple herbivore taxa. All taxa were fed pure alfalfa (Medicago sativa) diets for a minimum period of 6 months, at which point recently grown hair was shaved and analyzed for carbon isotopes. The mean observed diethair fractionation was +3.2, with a range of +2.7 to +3.5. We also examined dietfeces fractionation for herbivores on alfalfa and bermudagrass (Cynodon dactylon) feeds. The mean dietfeces fractionation for both diets was 0.8, with less fractionation for alfalfa (0.6) than bermudagrass (1.0). Fecal carbon turnover also varies greatly between taxa. When diets were switched, horse (Equus caballus) feces reflected the new diet within 60 h, but alpaca (Lama pacos) feces did not equilibrate with the new diet for nearly 200 h. Thus, fecal carbon isotopes provide far greater dietary resolution for hindgut-fermenting horses than foregut-fermenting alpacas.

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Jacovella, U., Jack T. Buntine, Mariah Cotter, Giel Muller, Michael S. Scholz et Emmanuel Dartois. « On the possible contribution of cationic oxygenated carbon chains CnO+, HCnO+, and OCnO+ (n = 4–9) to the diffuse interstellar bands ». Monthly Notices of the Royal Astronomical Society 511, n^o 4 (31 janvier 2022) : 5171–79. http://dx.doi.org/10.1093/mnras/stac277.

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ABSTRACT Only four of the diffuse interstellar bands (DIBs) are currently accounted for, ascribed to electronic transitions of C$_{60}^+$. Investigations into carriers of other DIBs historically focus on charged and neutral hydrocarbons, and little information is available regarding oxygenated carbon and hydrocarbon species that result from the two most abundant heavy elements in the interstellar medium, C and O. In this study, we assess whether CnO+, HCnO+, and OCnO+ (n = 4–9) cations are viable candidates to account for DIBs using both density-functional theory (DFT) and coupled cluster single-double and perturbative triple theory, CCSD(T). For these species, the linear structures are the most stable isomers with the lowest dissociation threshold corresponding to CO loss. Optical absorptions of the oxygenated carbon chain cations are characterized by calculated vertical excitation wavelengths and their corresponding oscillator strengths using the equation-of-motion CCSD (EOM-CCSD) method. Aside from HC4O+ and HC2n +1O+, all of the species considered in this study have calculated electronic transitions that lie in the visible or near-infrared spectral regions. Minimal column densities necessary for these cations to account for DIBs have been estimated. Based on present results and the known column densities for neutral oxygenated carbon chains in TMC-1, the growth rate of charged O-bearing carbon chains via ion-neutral reaction mechanisms is judged to be too low to form a sufficient population to give rise to DIBs.

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Eustachio Colombo, Patricia, Liselotte Schäfer Elinder, Anna Karin Lindroos et Alexandr Parlesak. « Designing Nutritionally Adequate and Climate-Friendly Diets for Omnivorous, Pescatarian, Vegetarian and Vegan Adolescents in Sweden Using Linear Optimization ». Nutrients 13, n^o 8 (22 juillet 2021) : 2507. http://dx.doi.org/10.3390/nu13082507.

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Low-carbon diets can counteract climate change and promote health if they are nutritionally adequate, affordable and culturally acceptable. This study aimed at developing sustainable diets and to compare these with the EAT-Lancet diet. The Swedish national dietary survey Riksmaten Adolescents 2016–2017 was used as the baseline. Diets were optimized using linear programming for four dietary patterns: omnivores, pescatarians, vegetarians and vegans. The deviation from the baseline Riksmaten diet was minimized for all optimized diets while fulfilling nutrient and climate footprint constraints. Constraining the diet-related carbon dioxide equivalents of omnivores to 1.57 kg/day resulted in a diet associated with a reduction of meat, dairy products, and processed foods and an increase in potatoes, pulses, eggs and seafood. Climate-friendly, nutritionally adequate diets for pescatarians, vegetarians and vegans contained fewer foods and included considerable amounts of fortified dairy and meat substitutes. The optimized diets did not align very well with the food-group pattern of the EAT-Lancet diet. These findings suggest how to design future diets that are climate-friendly, nutritionally adequate, affordable, and culturally acceptable for Swedish adolescents with different dietary patterns. The discrepancies with the EAT diet indicate that the cultural dietary context is likely to play an important role in characterizing sustainable diets for specific populations.

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Psathas, Petros, Edward Sander, Won Ryoo, Daniel Mitchell, Richard Lagow, Kwon Taek Lim et Keith Johnston. « Interfacial Studies of the Formation of Microemulsions of Water in Carbon Dioxide with Fluorinated Surfactants ». Journal of Dispersion Science and Technology 23, n^o 1&3 (2002) : 81–91. http://dx.doi.org/10.1081/dis-120003306.

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Ehrenfreund, P., N. Cox, J. Cami, B. H. Foing, L. Kaper, L. d’Hendecourt, J. P. Maier et al. « Magellanic Diffuse Interstellar Bands and Carbon Chemistry ». Highlights of Astronomy 13 (2005) : 864–66. http://dx.doi.org/10.1017/s1539299600017342.

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AbstractWith the Ultraviolet Visual Echelle Spectrograph mounted at the Very Large Telescope, we have observed at unprecedented spectral resolution the absorption spectrum toward reddened stars in the Magellanic Clouds over the wavelength range of 3500-10500 Å. This range covers the strong transitions associated with neutral and charged large carbon molecules of varying sizes and structures. We report the first detection of diffuse interstellar bands (DIBs) at 5780 and 5797 Å in the Small Magellanic Cloud and the variation of those DIBs toward several targets in the Large Magellanic Cloud. The variation of DIBs in the Magellanic Clouds compared with Galactic targets may be governed by a combination of the different chemical processes prevailing in low-metallicity regions and the local environmental conditions. The analysis of high-resolution absorption spectra allows us to reveal the global effects in the chemistry and recycling of cosmic dust in the Magellanic Clouds which are relevant for the chemical pathways forming large organic molecules in external galaxies.

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Herrmann, Marius, Björn Beckschwarte, Henning Hasselbruch, Julian Heidhoff, Christian Schenck, Oltmann Riemer, Andreas Mehner et Bernd Kuhfuss. « Diamond-Like-Carbon Coated Dies for Electromagnetic Embossing ». Materials 13, n^o 21 (3 novembre 2020) : 4939. http://dx.doi.org/10.3390/ma13214939.

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Electromagnetic forming is a high-speed process, which features contactless force transmission. Hence, punching operations can be realized with a one-sided die and without a mechanical punch. As the forces act as body forces in the part near the surface, the process is especially convenient for embossing microstructures on thin sheet metals. Nevertheless, the die design is critical concerning wear like adhesion. Several die materials were tested, like aluminum, copper as well as different steel types. For all die materials adhesion phenomena were observed. To prevent such adhesion an a-C:H-PVD (Physical Vapor Deposition)-coating was applied to steel dies (X153CrMoV12) and tested by embossing aluminum sheets (Al99.5). By this enhancement of the die adhesion was prevented. Furthermore, the die surface was structured with tribology-effective patterns that were generated by micro hard milling. The embossing quality was topographically analyzed with respect to different initial surface states of the sheets. It was identified that thicker sheets facilitate better embossing results. Moreover, the initial sheet surface has a decisive influence on the embossing quality, whereby the characteristic of the topography showed different susceptibility on the initial sheet surface state.

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Willits-Smith, Amelia, Miguel Angel Lopez, Keelia O'Malley et Diego Rose. « Self-Selected Diets in the US Show a Reduction in Carbon Footprints Over Ten Years ». Current Developments in Nutrition 6, Supplement_1 (juin 2022) : 83. http://dx.doi.org/10.1093/cdn/nzac050.013.

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Abstract Objectives Growing evidence indicates the need for demand-side changes to global food systems to meet nutritional needs while staying within planetary boundaries. Previous research documented the greenhouse gas emissions (GHGE, or carbon footprint) of self-selected diets in the US from the 2005–2010 National Health and Nutrition Examination Survey (NHANES), but more recent such data do not exist. To address this gap, we assessed the carbon footprint of diets reported in the 2015–2016 NHANES, and analyzed the 10-year trend from the 2005–2006 wave. Methods Foods eaten by adults (N = 5,060), ages 18 years and older, reported in a one-day 24-hour recall in NHANES 2005–2006 were translated to commodity intakes using recipes from the US Environmental Protection Agency's Food Commodity Intake Database (FCID). GHGE (kg carbon dioxide equivalents, or CO2-eq, per kg of edible portion) in the production of these commodities were calculated from the database of Food Impacts on the Environment for Linking to Diets (dataFIELD), then summed for each person to get a total one-day dietary carbon footprint. Newly reported foods consumed by adults (N = 4,982) in 2015–2016 required new recipes to be translated to commodity intakes. We developed these recipes by modifying similar existing FCID recipes. If no similar food existed, recipes were constructed using ingredients and proportions from the US Department of Agriculture's FoodData Central. Results Mean food-related GHGE decreased 7.9% across the ten-year period, from 4.9 to 4.5 kg CO2-eq/day. Controlling for energy intake, age, gender, race, and income-to-poverty ratio, one-day food-related GHGE were still lower in 2015–2016 than they were in 2005–2006, by 0.3 kg CO2-eq (p < 0.02). Conclusions The average carbon footprint of US adults’ self-selected diets has decreased over time. This is a positive development for efforts to slow climate change. However, evidence reported elsewhere shows that US diets do not meet current nutritional recommendations. Additional research is needed to find and encourage “win-win” diets that meet nutritional objectives, while reducing environmental impacts. Funding Sources Wellcome Trust, National Cancer Institute, Health Resources and Services Administration.

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Da Silveira, Lidimara Souza, Renato Tavares Martins et Roberto da Gama Alves. « Invertebrate Colonization During Leaf Decomposition of Eichhornia azurea (Swartz) Kunth (Commelinales : Pontoderiaceae) and Salvinia auriculata Aubl. (Salvinales : Salvinaceae) in a Neotropical Lentic System ». EntomoBrasilis 9, n^o 1 (29 avril 2016) : 10–17. http://dx.doi.org/10.12741/ebrasilis.v9i1.548.

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Abstract. The decomposition of macrophytes is an essential process for cycling of carbon and nutrients, and it is source of organic matter for invertebrates in lakes. We evaluated the colonization by aquatic invertebrates in decomposing leaves of two species of macrophytes in a Neotropical lentic system. The experiment was conducted from November 2007 to February 2008, with the use of 54 litter bags (Eichhornia azurea (Swartz): n = 27 and Salvinia auriculata Aubl.: n= 27), each containing 10 g of dry leaves. Three bags of each species were retrieved after 2, 4, 8, 12, 24, 36, 48, 60 and 72 days of incubation. The remaining leaf mass of the two macrophytes species tended to decrease with time, although at different rates. The decomposition of E. azurea and S. auriculata leaves were classified as rapid and intermediate, respectively. In general, during the experiment carbon: nitrogen ratio declined in E. azurea and increased in S. auriculata, and presented difference among the days of the experiment and between the macrophyte species. In E. azurea mass loss was negatively correlated with carbon: nitrogen ratio of the leaves, but the same pattern was not observed for the S. auriculata leaves. The composition and richness of invertebrates differed among days, but not between macrophytes species. We concluded that the succession process along the detritus chain was more important in structuring the invertebrate community than the variation in the nutritional quality of the leaf litter for these two species of macrophytes.Colonização por Invertebrados Durante a Decomposição foliar de Eichhornia azurea (Swartz) Kunth (Commelinales: Pontoderiaceae) e Salvinia auriculata Aubl. (Salvinales: Salvinaceae) em um Sistema Lêntico NeotropicalResumo. A decomposição de macrófitas é um processo essencial para ciclagem de carbono e nutrientes, e é fonte de matéria orgânica para invertebrados em lagos. Avaliamos a colonização por invertebrados aquáticos em folhas em decomposição de duas espécies de macrófitas em um sistema lêntico Neotropical. O experimento foi conduzido entre novembro de 2007 e fevereiro de 2008, com a utilização de 54 sacos de detrito (Eichhornia azurea (Swartz): n = 27 e Salvinia auriculata Aubl.: n = 27), cada um contendo 10 g de folhas secas. Três sacos de cada espécie foram recuperados após 2, 4, 8, 12, 24, 36, 48, 60 e 72 dias de incubação. A massa remanescente de folha das duas espécies de macrófitas tendeu a diminuir com o tempo, embora a velocidades diferentes. A decomposição de folhas de E. azurea e S. auriculata foram classificadas como rápida e intermédia, respectivamente. Em geral, durante o experimento a razão carbono: nitrogênio diminuiu em E. azurea e aumentou em S. auriculata, e apresentou diferença entre os dias de experimento e entre as espécies de macrófitas. Em E. azurea perda de massa foi negativamente correlacionada com a razão de carbono: nitrogênio das folhas, mas o mesmo padrão não foi observado para as folhas de S. auriculata. A composição e riqueza de invertebrados diferiram entre os dias, mas não entre espécies de macrófitas. Concluímos que o processo de sucessão ao longo da cadeia de detritos foi mais importante na estruturação da comunidade de invertebrados do que a variação na qualidade nutricional do detrito de folha para estas duas espécies de macrófitas.

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Murakawa, M., N. Koga et S. Takeuchi. « Diamondlike Carbon-Coated Dies for Deep Drawing of Aluminum Sheets ». Journal of Manufacturing Science and Engineering 121, n^o 4 (1 novembre 1999) : 674–78. http://dx.doi.org/10.1115/1.2833101.

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Soft and hard diamondlike carbon die coatings were used to deep draw aluminum sheets with a very light and environment-friendly water-soluble oil lubricant and even without a lubricant. The water-soluble oil lubricant with poor lubrication ability caused premature rupture of the aluminum blank when drawn with a noncoated steel die, whereas a die coated with soft diamondlike carbon (WC/C) had a lifetime of over 7000 drawing operations. A cost-effective die could be made of a die steel body on which a sintered tungsten carbide alloy overlayer was deposited by high-velocity thermal spraying and further coated with a hard diamondlike carbon (DLC), which gave a life of up to 6000 operations even without a lubricant. Tool life was almost equal to that for a solid sintered carbide alloy die coated with DLC.

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Hadwen, Wade L., et Stuart E. Bunn. « Tourists increase the contribution of autochthonous carbon to littoral zone food webs in oligotrophic dune lakes ». Marine and Freshwater Research 55, n^o 7 (2004) : 701. http://dx.doi.org/10.1071/mf04068.

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Tourists can adversely influence the ecology of oligotrophic lakes by increasing algal production via direct nutrient inputs and/or re-suspension of sediments. To assess the influence of tourists on food web dynamics, we used the natural abundance of stable isotopes of carbon and nitrogen to calculate the relative importance of autochthonous and allochthonous carbon sources to littoral zone food webs across five variously visited perched dune lakes on Fraser Island, Australia. The relative importance of autochthonous (phytoplankton and periphyton) carbon to littoral zone consumers was highly variable across taxa and lakes. Despite the potential influence of algal biomass, ambient nutrient concentrations and tannin concentrations on the contribution of autochthonous carbon to littoral zone food webs, none of these variables correlated to the per cent contribution of autochthonous carbon to consumer diets. Instead, autochthonous sources of carbon contributed more to the diets of aquatic consumers in heavily visited lakes than in less visited lakes, suggesting that tourist activities might drive these systems towards an increased reliance on autochthonous carbon. The assessment of the contribution of autochthonous carbon to littoral zone food webs may represent a more robust indicator of the impact of tourists in oligotrophic lakes than standard measures of nutrient concentrations and/or algal biomass.

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Yan, Wentao, Dafa Jiang, Xiao Yuan, Bin Zhou et Feng Lin. « A novel design of a high-strength high-temperature graphite die ». Proceedings of the Institution of Mechanical Engineers, Part E : Journal of Process Mechanical Engineering 233, n^o 1 (16 janvier 2018) : 138–46. http://dx.doi.org/10.1177/0954408917753531.

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Graphite die is a critical component in material processing, especially at high temperature. However, its strength is a bottleneck. In this study, we propose a novel, efficient, and economical solution to remarkably enhance the strength of graphite dies by employing the pre-stressed carbon fiber winding technology. An engineering application of a graphite die for hot pressing at 1273 K demonstrated the reliability and practicality: the original graphite die breaks under a punch pressure of 70 MPa and the carbon fiber wound graphite dies work well under a punch pressure up to 100 MPa. The finite element simulations illustrate that the 1-mm-thick layer of carbon fiber is able to reduce the maximum principal stress of the graphite die effectively from 130 MPa to 30 MPa. This is the first application of the pre-stressed carbon fiber winding technique to high-temperature components.

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Damanhuri, Deni, Ahmad Iskandar et Muhammad Rafif Asy-syauqi. « Analisis Karakteristik Material Cutting Tools Extrudertwin Screw Type Spring Steel 1074 ». Motor Bakar : Jurnal Teknik Mesin 6, n^o 1 (2 août 2022) : 1. http://dx.doi.org/10.31000/mbjtm.v6i1.6664.

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Dalam dunia industri manufacture, mesin extruder banyak digunakan untuk memproduksi kebutuhan rumah tanggga yang berbahan plastik. Salah satu mesin yang dapat memproduksi plastik dengan kapasitas dan kualitas yang baik tersebut adalah mesin extruder twin screw. Maka dari itu cutting perlu di lakukan pengujian supaya kita mengetahui karateristik dan struktur mikro dari material cutting tools type A228 dan cutting tools type AISI 1074 yang maksimal, maka di lakukan pengujian terkait performa terhadap kapasitas, down time, reject serta ketahanan terhadap gesekan dies. Metode yang digunakan dalam penelitian ini adalah metode eksperimen. Hasil pengujian terhadap karateristik kekerasan cutting tools type A228 di hasilkan kekerasan rata rata 877 hv dan hasil pengujian terhadap karateristik kekerasan cutting tools type AISI 1074 di hasilkan kekerasan rata rata 511.2 hv. Hasil pengujian komposisi kimia di hasilkan, kadar carbon yang terkandung di dalam cutting tools type A228 sebesar 0,814%, dengan hasil tersebut cutting tools type A228 masuk dalam kelompok medium carbon steel. Hasil pengujian komposisi kimia di hasilkan, kadar carbon yang terkandung di dalam cutting tools type AISI 1074 sebesar 0.735%, dengan hasil tersebut cutting tools type AISI 1074 masuk dalam kelompok medium carbon steel. Pengujian pemakaian di lapangan cutting tools type AISI 1074 mampu menurunkan down time sebesar 54 menit selama satu bulan beroperasi terhadap dies. Untuk kapasitas cutting tools type AISI 1074 mampu menekan angka reject sebesar 59 kg, dan terkait performa terhadap ketahanan gesekan, cutting tools type AISI 1074 mampu menurunkan angka penggantian dies sebanyak 27 kali pergantian. Secara keseluruhan cutting tools type A228 mampu menurunkan down time, reject, pergantian cutting terhadap dies .

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Machado, Glauco B. O., Fosca P. P. Leite et Erik E. Sotka. « Nutrition of marine mesograzers : integrating feeding behavior, nutrient intake and performance of an herbivorous amphipod ». PeerJ 6 (9 novembre 2018) : e5929. http://dx.doi.org/10.7717/peerj.5929.

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Consumers can regulate the acquisition and use of nutrients through behavioral and physiological mechanisms. Here, we present an experimental approach that simultaneously integrates multiple nutritional traits, feeding assays, and juvenile performance to assess whether a marine herbivore (the amphipod Ampithoe valida) regulates the intake of elements (carbon and nitrogen), macronutrients (protein and non-protein) or both when offered freeze-dried tissues of seaweeds varying in nutritional content. We assessed behavioral regulation of nutrients in three ways. First, during no-choice assays, we found that amphipods ingested similar amounts of carbon, but not nitrogen, non-protein and protein, across algal diets. Second, herbivore intake rates of carbon, protein and non-protein components across no-choice assays was similar to intake rates when offered a choice of foods. Third, variation in intake rates of carbon and non-protein components among algal diets was significantly greater than was tissue content of these components, while variation in intake rates of nitrogen was significantly lower; differences in protein intake variation was equivocal. While these analytical approaches are not uniformly consistent, carbon and nitrogen seem to emerge as the nutrient components that are more strongly regulated by A. valida. Juveniles reared on single diets shown patterns of survivorship, growth and reproduction that could not be predicted by these feeding preferences, nor nutrient content. We conclude that an integrative approach that considers the intake of multiple nutrients potentially yields insights into feeding behavior and its performance consequences.

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ITO, Hiroaki, Shin MURAMATSU, Koh-ichi SUGIMOTO, Hajime OSAKA et Takafumi SATO. « Electrical Discharge Machining of Glass-like Carbon/Vapor Grown Carbon Fiber Composite Dies ». Journal of the Japan Society for Precision Engineering 76, n^o 4 (2010) : 443–47. http://dx.doi.org/10.2493/jjspe.76.443.

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Reis, Daiane Felix, Francisco Roberto da Silva Machado Junior, Joana Da Costa Ores, Ailton Cesar Lemes, Carlos Andre Veiga Burkert et Janaina Fernandes de Medeiros Burkert. « Influência do CO2 no Crescimento de Haematococcus Pluvialis e na Produção de Carotenoides ». UNICIÊNCIAS 22, n^o 3Esp (24 janvier 2019) : 25. http://dx.doi.org/10.17921/1415-5141.2018v22n3espp25-29.

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O crescimento celular da microalga de água doce Haematococcus pluvialis e a bioprodução de carotenoides são influenciados pelas diferentes condições de cultivo, como deficiência de nutrientes, iluminância, aeração, agitação, temperatura e pH, alterando sua morfologia celular e produzindo cistos avermelhados (carotenogênese). A aeração nos cultivos de microalgas está relacionada a alguns fatores que influenciam no crescimento celular. As microalgas absorvem e utilizam CO2 como a principal fonte de carbono no crescimento celular. Logo, a biossíntese de pigmentos pode ocorrer pela limitação do nitrogênio em presença de excesso de fontes de carbono. O objetivo desse trabalho foi investigar a influência do emprego de CO2 na aeração do cultivo da microalga Haematococcus pluvialis sob o crescimento celular e a bioprodução de carotenoides. No cultivo foi utilizado o meio mixotrófico BBM (Bold Basal Medium) e acetato de sódio, empregando 20% de inóculo em pH inicial de 7,0, aeração de 0,30 L.min-1, com 30% de injeção de CO2 uma vez ao dia durante 1 h, sob iluminância de 6 klux, à 25 ºC durante 22 dias. Nestas condições o crescimento celular alcançou o máximo de 1,13±0,39 g.L-1 (10 dias) e os carotenoides totais 2949,91±988,65 µg.g-1, onde foi observado que a suplementação de CO2 como fonte de carbono dissolvida no meio de cultivo pode influenciar o crescimento celular e os carotenoides totais. Palavras-chave: Microalga. Pigmento. Aeração. Cultivo. AbstractThe cellular growth of the freshwater microalgae Haematococcus pluvialis and the bioproduction of carotenoids are influenced by the different culture conditions, such as nutrient deficiency, illuminance, aeration, agitation, temperature and pH, altering its cellular morphology and producing reddish cysts (carotenogenesis). Aeration in microalgae cultures is related to some factors that influence cell growth. Microalgae absorb and utilize CO2 as the main source of carbon in cell growth. Therefore, the biosynthesis of pigments can occur by the limitation of nitrogen in the presence of excess carbon sources. The objective of this work was to investigate the influence of the use of CO2 on the aeration of the microalgae Haematococcus pluvialis under cell growth and bioproduction of carotenoids. In the culture, mixotrophic medium BBM (Bold Basal Medium) and sodium acetate were used, using 20% of inoculum at initial pH of 7.0, aeration of 0.30 L.min-1, with 30% of CO2 injection once a day for 1 h under 6 Klux illuminance at 25 ° C for 22 days. Under these conditions the cell growth reached a maximum of 1.13 ± 0.39 g. L-1 (10 days) and the total carotenoids 2949.91 ± 988.65 μg.g-1, where it was observed that CO2 supplementation as a source of carbon dissolved in the culture medium may influence cell growth and total carotenoids. Keywords: microalgae; pigment; aeration; cultivation.

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GA, Mousa. « Fungal Pectinase Production Optimization and its Application in Buffaloe’s Diets Degradation ». International Journal of Zoology and Animal Biology 3, n^o 1 (2020) : 1–12. http://dx.doi.org/10.23880/izab-16000199.

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Pectinase production for improving buffalo’s diets digestion is the main objective of this work. Effects of fungal strains and different cultivation conditions on pectinase production have been studied. In vitro batch culture technique was used for investigate impact of the produced pectinase compared with commercial pectinase (SMIZYME ® ) on rumen fermentation parameters and diet degradation. Penicillium chrysogenum exhibited the highest pectinase activity at 3 days of incubation period , initial pH 4 of the growth medium, yeast extract as a sole nitrogen source and pomegranate peel as a carbon source at a concentration of 15 % (W/V). Three (g/kg) of the both enzymes supplementation significantly increased treated diet’s dry matter (DM), neutral detergent fiber (NDF), acid detergent fiber (ADF) degradability with increase total gas production ( TGP) and short chain fatty acids (SCFA) concentration. The enlargement of pectinase production locally will lead to animal production improvement, encourage self-reliance and reduce the cost of enzymes importation.

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Rose, Donald, Martin C. Heller, Amelia M. Willits-Smith et Robert J. Meyer. « Carbon footprint of self-selected US diets : nutritional, demographic, and behavioral correlates ». American Journal of Clinical Nutrition 109, n^o 3 (29 janvier 2019) : 526–34. http://dx.doi.org/10.1093/ajcn/nqy327.

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ABSTRACT Background A substantial portion of greenhouse gas emissions (GHGE) has been attributed to the food sector, but little is known about the association between the carbon footprint of individual self-selected diets in the United States and nutritional quality. Objectives The aims of this study were to assess the GHGE from individual self-selected diets in the United States and examine their association with nutritional quality of the diets, demographic patterns, and food-related behaviors. Methods The dietary GHGE from US adults (>18 y, N = 16,800) in the 2005–2010 National Health and Nutrition Examination Survey (NHANES) were calculated by linking all foods consumed in their 24-h recall diets to our new database of food environmental impacts. Diets were ranked by GHGE/1000 kcal. Those in the top and bottom quintiles were compared on the US Healthy Eating Index (HEI) and on the amounts of specific nutrients known to be under- or overconsumed in the US population. Demographic and behavioral variables from the NHANES were also correlated to these dietary carbon footprints. Results Diets in the bottom quintile accounted for one-fifth the total emissions (GHGE/1000 kcal) of those in the top quintile, yet had significantly higher (P < 0.001) HEI scores by 2.3 ± 0.7 points on a 100-point scale. These low-GHGE diets contained higher amounts of fiber and vitamin E and lower amounts of sodium and saturated fats, whereas high-GHGE diets contained higher amounts of vitamins A and D, choline, calcium, iron, and potassium. Low-GHGE diets had less meat, dairy, and solid fats, and more poultry, plant protein foods, oils, whole and refined grains, and added sugars. Conclusions Food patterns responsible for lower GHGE had a better overall diet quality and were more nutritious on several key dimensions, although not all. These results can inform dietary guidance and other policies that seek to address the goals of improved dietary intakes and reduced food-related emissions.

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Wainfan, Elsie, Mark Dizik, Margaret Hluboky et M. Earl Balis. « Altered tRNA methylation in rats and mice fed lipotrope-deficient diets ». Carcinogenesis 7, n^o 3 (1986) : 473–76. http://dx.doi.org/10.1093/carcin/7.3.473.

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Ebrahimnia, Mohamad, Hamzeh Baghjari, Mohamad Ajdari, Alireza Hajesmaeli et Milad Hojati. « Application of a Low Heat Input Deposition Process for Refurbishment of Worn PM Forming Dies Using Fe-Ni Based Filler Metal ». Powder Metallurgy Progress 18, n^o 2 (1 novembre 2018) : 116–20. http://dx.doi.org/10.1515/pmp-2018-0013.

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Abstract Refurbishment of worn Dies is an interesting research area which also has high economic benefit. Material which is used in PM dies for compacting powders are high carbon steel which have very low weldabilitis. Due to the high hardness, high carbon content and martensitic microstructure, these Dies are very sensitive to the thermal shock produced from fusion welding. For successfully refurbishing the worn Dies, Fine spark deposition was used for deposition of a new layer on the cold work 1.2436 steel. Different heat inputs were used for deposition of nickel based material and finally microstructure and HAZ were studied. Results show the HAZ area is very narrow, free from cracks and HAZ microstructure is similar to the base metal. GTAW welding using same filler metal induced many cracks in HAZ of weld which is detrimental to the refurbished Die performance. Results show increasing heat input in Fine spark deposition can results in crack formation in HAZ even if the weld pool does not occurred in base metal. However these cracks are much smaller than those occurred in GTAW.

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Xu, Bing, Zhaoyan Gu, Jingtai Han, Zongxiu Liu, Yunpeng Pei, Yanwu Lu, Naiqin Wu et Yongfu Chen. « Radiocarbon and Stable Carbon Isotope Analyses of Land Snails from the Chinese Loess Plateau : Environmental and Chronological Implications ». Radiocarbon 52, n^o 1 (2010) : 149–56. http://dx.doi.org/10.1017/s0033822200045094.

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Paired radiocarbon and stable carbon analyses have been carried out on aragonite shells and organic soft bodies of snails from the Chinese Loess Plateau in order to explore the possibility of using these kinds of samples as environmental and chronological indicators. Results show that the soft bodies exhibit 14C concentrations similar to those of plant leaves, indicating that carbon in the soft bodies is fixed from organic diets. The aragonite shells are depleted in 14C compared to the soft bodies due to ingestion of 14C-depleted carbonate. This depletion shows a consistent pattern across the Chinese Loess Plateau, implying a good potential for the snail shells to be applicable for 14C dating with a simple correction. The δ13C values measured for aragonite shells display a linear relationship with those obtained for the soft bodies with a constant offset. In addition, the carbon derived from organic diets accounts for more than 70% of the total shell carbon. This fact suggests that stable carbon isotope composition of aragonite shells mainly reflects that of organic diet, and could be used as a reliable indicator of paleodiet in the Chinese Loess Plateau.

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Pitcher, C. S., P. C. Stangeby, D. H. J. Goodall, G. F. Matthews et G. M. McCracken. « Carbon impurity transport around limiters in the DITE tokamak ». Journal of Nuclear Materials 162-164 (avril 1989) : 337–42. http://dx.doi.org/10.1016/0022-3115(89)90291-2.

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Capozzi, Vito, Cristina Flesia et Antonio Minafra. « Anomalous dips in extinction spectra of disordered carbon grains ». Optics Communications 68, n^o 3 (octobre 1988) : 166–70. http://dx.doi.org/10.1016/0030-4018(88)90177-0.

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Zack, L. N., et J. P. Maier. « Laboratory Electronic Spectra of Carbon Chains and Rings ». Proceedings of the International Astronomical Union 9, S297 (mai 2013) : 237–46. http://dx.doi.org/10.1017/s1743921313015949.

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AbstractCarriers of the diffuse interstellar bands (DIBs) cannot be definitively identified without laboratory spectra. Several techniques, including matrix isolation, cavity ringdown spectroscopy, resonance enhanced multiphoton ionization, and ion trapping, have been used to measure the electronic spectra of carbon chains and their derivatives. The gas-phase laboratory spectra could then be compared to the astronomical data of known DIBs. The choice of molecules studied in the gas phase depends on the presence of strong electronic transitions at optical wavelengths, the lifetimes of excited electronic states, and chemical feasibility in diffuse astrophysical environments. Collisional-radiative rate models have also be used in conjunction with laboratory spectra to predict absorption profiles under interstellar conditions.

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Halffman, Carrin M., Ben A. Potter, Holly J. McKinney, Takumi Tsutaya, Bruce P. Finney, Brian M. Kemp, Eric J. Bartelink et al. « Ancient Beringian paleodiets revealed through multiproxy stable isotope analyses ». Science Advances 6, n^o 36 (septembre 2020) : eabc1968. http://dx.doi.org/10.1126/sciadv.abc1968.

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The earliest Native Americans have often been portrayed as either megafaunal specialists or generalist foragers, but this debate cannot be resolved by studying the faunal record alone. Stable isotope analysis directly reveals the foods consumed by individuals. We present multi-tissue isotope analyses of two Ancient Beringian infants from the Upward Sun River site (USR), Alaska (~11,500 years ago). Models of fetal bone turnover combined with seasonally-sensitive taxa show that the carbon and nitrogen isotope composition of USR infant bone collagen reflects maternal diets over the summer. Using comparative faunal isotope data, we demonstrate that although terrestrial sources dominated maternal diets, salmon was also important, supported by carbon isotope analysis of essential amino acids and bone bioapatite. Tooth enamel samples indicate increased salmon use between spring and summer. Our results do not support either strictly megafaunal specialists or generalized foragers but indicate that Ancient Beringian diets were complex and seasonally structured.

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Korb, Rebecca. « Lack of dietary specialization in adult Aplysia californica : evidence from stable carbon isotope composition ». Journal of the Marine Biological Association of the United Kingdom 83, n^o 3 (9 avril 2003) : 501–5. http://dx.doi.org/10.1017/s0025315403007422h.

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Natural abundance, 13C/12C ratios (δ13C) of Californian sea hares, Aplysia californica, (Gastropoda: Opisthobranchia) were measured for comparison with the animals preferred red algal diets, Plocamium cartilagineum and Laurenciapacifica. Isotopic compositions of animals collected from around Santa Catalina Island, did not reflect those of the favoured red algal diets, nor the majority of algal species found in the field. However, animals held in seawater tanks and fed diets with a constant carbon isotopic composition exhibited δ13C values similar to their food. Fast turnover tissue, such as the muscle tissue of actively growing juveniles or egg masses laid by adults, showed δ13C values within ±2‰ of the algal diet. Slow turnover tissue, such as the muscle tissue of large adults, reflected the diet over several months. Stable carbon isotope ratios thus proved a useful tool to clarify the extent to which specialized feeding in A. californica can occur upon algae which are only moderately to rarely common.

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Gerasimova, Alla A., Sergey Gorbatyuk et Dmitry Efremov. « Modeling of Tool for Cold Extrusion of Steel and Tooling with Proportional Bandaging ». Solid State Phenomena 299 (janvier 2020) : 513–17. http://dx.doi.org/10.4028/www.scientific.net/ssp.299.513.

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In the article the results of the finite element modeling of cold extrusion of carbon steel, the stress-strain state of massive dies at high cyclic stresses characteristic of the cold extrusion of steel are presented. The possibility of significant amplification of dies in their working area by creating a variable external pressure from the rims of a special design is shown. Dies banding with variable external pressure, proportional to the internal pressure in the die, is aimed at increasing the technical resource of the tool.

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Wainfan, Elsie, Mark Dizik, Martin Kilkenny et James P. O'Callaghan. « Prolonged survival of female AKR mice fed diets supplemented with methionine and choline ». Carcinogenesis 11, n^o 3 (1990) : 361–63. http://dx.doi.org/10.1093/carcin/11.3.361.

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Reinikainen, Michael, Anthony W. D’Amato, John B. Bradford et Shawn Fraver. « Influence of stocking, site quality, stand age, low-severity canopy disturbance, and forest composition on sub-boreal aspen mixedwood carbon stocks ». Canadian Journal of Forest Research 44, n^o 3 (mars 2014) : 230–42. http://dx.doi.org/10.1139/cjfr-2013-0165.

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Low-severity canopy disturbance presumably influences forest carbon dynamics during the course of stand development, yet the topic has received relatively little attention. This is surprising because of the frequent occurrence of such events and the potential for both the severity and frequency of disturbances to increase as a result of climate change. We investigated the impacts of low-severity canopy disturbance and average insect defoliation on forest carbon stocks and rates of carbon sequestration in mature aspen mixedwood forests of varying stand age (ranging from 61 to 85 years), overstory composition, stocking level, and site quality. Stocking level and site quality positively affected the average annual aboveground tree carbon increment (CAAI), while stocking level, site quality, and stand age positively affected tree carbon stocks (CTREE) and total ecosystem carbon stocks (CTOTAL). Cumulative canopy disturbance (DIST) was reconstructed using dendroecological methods over a 29-year period. DIST was negatively and significantly related to soil carbon (CSOIL), and it was negatively, albeit marginally, related to CTOTAL. Minima in the annual aboveground carbon increment of trees (CAI) occurred at sites during defoliation of aspen (Populus tremuloides Michx.) by forest tent caterpillar (Malacosoma disstria Hubner), and minima were more extreme at sites dominated by trembling aspen than sites mixed with conifers. At sites defoliated by forest tent caterpillar in the early 2000s, increased sequestration by the softwood component (Abies balsamea (L.) Mill. and Picea glauca (Moench) Voss) compensated for overall decreases in CAI by 17% on average. These results underscore the importance of accounting for low-severity canopy disturbance events when developing regional forest carbon models and argue for the restoration and maintenance of historically important conifer species within aspen mixedwoods to enhance stand-level resilience to disturbance agents and maintain site-level carbon stocks.

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Auclair, Olivia, et Sergio A. Burgos. « Carbon Footprint of Canadian Self-Selected Diets : Trade-Offs With Nutrient Intakes and Diet Quality ». Current Developments in Nutrition 5, Supplement_2 (juin 2021) : 84. http://dx.doi.org/10.1093/cdn/nzab060_002.

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Abstract Objectives Individuals' dietary choices are critical determinants of human and planetary health. Although the environmental impact of animal-based foods typically exceeds that of plants, trade-offs among nutritional outcomes and environmental sustainability in the context of self-selected diets are less understood. The objectives were to estimate the carbon footprint of Canadian self-selected diets and to compare low- and high-GHGE diets in terms of intake of food groups, nutrients, and diet quality. Methods Twenty-four-hour recalls from the 2015 Canadian Community Health Survey (CCHS) – Nutrition were used to determine dietary intake among adults ≥19 y (n = 13,612). Estimates from the database of Food Impacts on the Environment for Linking to Diets were used to link foods and beverages reported in the CCHS to their greenhouse gas emissions (GHGE). Intake of food groups, nutrients, and diet quality based on the Alternative Healthy Eating Index – 2010 were compared between low- and high-GHGE diets (lowest and highest quintiles of dietary GHGE expressed per 1,000 kcal). Results Dietary GHGE (mean ± SE) was 3.98 ± 0.06 kg CO2-equivalents (eq) per person per d or 2.15 ± 0.03 kg CO2-eq per person per 1,000 kcal. Animal-based foods contributed three-quarters of Canadians' total dietary GHGE, with red and processed meat alone accounting for 47.05 ± 0.82%. High-GHGE diets contained more animal-based foods, but also more vegetables and fruits and miscellaneous foods and beverages; low-GHGE diets contained more cereals, grains, and breads. High-GHGE diet respondents had higher intakes of nutrients of public health concern (iron, potassium, calcium, and vitamin D), but also higher intakes of nutrients to limit (saturated fat and sodium). Moreover, low-GHGE diets had higher diet quality scores compared to high-GHGE diets (55.31 ± 0.49 vs. 47.27 ± 0.46 points; p < 0.0001). Conclusions Self-selected Canadian diets with the highest GHGE contained more animal-based foods and were characterized by higher intakes of nutrients of concern but a lower overall diet quality. These trade-offs warrant attention in shaping future food policy and dietary guidance in Canada aimed at meeting global targets for climate change. Funding Sources None.

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