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Littérature scientifique sur le sujet « LdtE »

Auteur : Grafiati

Publié le 9 mars 2023

Mis à jour le 10 mars 2023

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Articles de revues sur le sujet "LdtE"

Hernández, Sara B., Sónia Castanheira, M. Graciela Pucciarelli, Juan J. Cestero, Gadea Rico-Pérez, Alberto Paradela, Juan A. Ayala et al. « Peptidoglycan editing in non-proliferating intracellular Salmonella as source of interference with immune signaling ». PLOS Pathogens 18, n^o 1 (25 janvier 2022) : e1010241. http://dx.doi.org/10.1371/journal.ppat.1010241.

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Salmonella enterica causes intracellular infections that can be limited to the intestine or spread to deeper tissues. In most cases, intracellular bacteria show moderate growth. How these bacteria face host defenses that recognize peptidoglycan, is poorly understood. Here, we report a high-resolution structural analysis of the minute amounts of peptidoglycan purified from S. enterica serovar Typhimurium (S. Typhimurium) infecting fibroblasts, a cell type in which this pathogen undergoes moderate growth and persists for days intracellularly. The peptidoglycan of these non-proliferating bacteria contains atypical crosslinked muropeptides with stem peptides trimmed at the L-alanine-D-glutamic acid-(γ) or D-glutamic acid-(γ)-meso-diaminopimelic acid motifs, both sensed by intracellular immune receptors. This peptidoglycan has a reduced glycan chain average length and ~30% increase in the L,D-crosslink, a type of bridge shared by all the atypical crosslinked muropeptides identified. The L,D-transpeptidases LdtD (YcbB) and LdtE (YnhG) are responsible for the formation of these L,D-bridges in the peptidoglycan of intracellular bacteria. We also identified in a fraction of muropeptides an unprecedented modification in the peptidoglycan of intracellular S. Typhimurium consisting of the amino alcohol alaninol replacing the terminal (fourth) D-alanine. Alaninol was still detectable in the peptidoglycan of a double mutant lacking LdtD and LdtE, thereby ruling out the contribution of these enzymes to this chemical modification. Remarkably, all multiple mutants tested lacking candidate enzymes that either trim stem peptides or form the L,D-bridges retain the capacity to modify the terminal D-alanine to alaninol and all attenuate NF-κB nuclear translocation. These data inferred a potential role of alaninol-containing muropeptides in attenuating pro-inflammatory signaling, which was confirmed with a synthetic tetrapeptide bearing such amino alcohol. We suggest that the modification of D-alanine to alaninol in the peptidoglycan of non-proliferating intracellular S. Typhimurium is an editing process exploited by this pathogen to evade immune recognition inside host cells.

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Falchi, Federica A., Flaviana Di Lorenzo, Roberto Pizzoccheri, Gianluca Casino, Moira Paroni, Francesca Forti, Antonio Molinaro et Federica Briani. « Overexpression of lpxT Gene in Escherichia coli Inhibits Cell Division and Causes Envelope Defects without Changing the Overall Phosphorylation Level of Lipid A ». Microorganisms 8, n^o 6 (30 mai 2020) : 826. http://dx.doi.org/10.3390/microorganisms8060826.

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LpxT is an inner membrane protein that transfers a phosphate group from the essential lipid undecaprenyl pyrophosphate (C-55PP) to the lipid A moiety of lipopolysaccharide, generating a lipid A tris-phosphorylated species. The protein is encoded by the non-essential lpxT gene, which is conserved in distantly related Gram-negative bacteria. In this work, we investigated the phenotypic effect of lpxT ectopic expression from a plasmid in Escherichia coli. We found that lpxT induction inhibited cell division and led to the formation of elongated cells, mostly with absent or altered septa. Moreover, the cells became sensitive to detergents and to hypo-osmotic shock, indicating that they had cell envelope defects. These effects were not due to lipid A hyperphosphorylation or C-55PP sequestering, but most likely to defective lipopolysaccharide transport. Indeed, lpxT overexpression in mutants lacking the L,D-transpeptidase LdtD and LdtE, which protect cells with outer membrane defects from osmotic lysis, caused cell envelope defects. Moreover, we found that pyrophosphorylated lipid A was also produced in a lpxT deletion mutant, indicating that LpxT is not the only protein able to perform such lipid A modification in E. coli.

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Sanders, Akeisha N., Lori F. Wright et Martin S. Pavelka. « Genetic characterization of mycobacterial l,d-transpeptidases ». Microbiology 160, n^o 8 (1 août 2014) : 1795–806. http://dx.doi.org/10.1099/mic.0.078980-0.

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l,d-Transpeptidases (Ldts) catalyse the formation of 3–3 cross-links in peptidoglycans (PGs); however, the role of these enzymes in cell envelope physiology is not well understood. Mycobacterial PG contains a higher percentage of 3–3 cross-links (~30–80 %) than the PG in most other bacteria, suggesting that they are particularly important to mycobacterial cell wall biology. The genomes of Mycobacterium tuberculosis and Mycobacterium smegmatis encode multiple Ldt genes, but it is not clear if they are redundant. We compared the sequences of the Ldt proteins from 18 mycobacterial genomes and found that they can be grouped into six classes. We then constructed M. smegmatis strains lacking single or multiple Ldt genes to determine the physiological consequence of the loss of these enzymes. We report that of the single mutants, only one, ΔldtC (MSMEG_0929, class 5), displayed an increased susceptibility to imipenem – a carbapenem antibiotic that inhibits the Ldt enzymes. The invariant cysteine in the active site of LdtC was required for function, consistent with its role as an Ldt. A triple mutant missing ldtC and both of the class 2 genes displayed hypersusceptibility to antibiotics, lysozyme and d-methionine, and had an altered cellular morphology. These data demonstrated that the distinct classes of mycobacterial Ldts may reflect different, non-redundant functions and that the class 5 Ldt was peculiar in that its loss, alone and with the class 2 proteins, had the most profound effect on phenotype.

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Genzen, Jonathan R., Jeffrey S. Mohlman, Jerry L. Lynch, Michael W. Squires et Ronald L. Weiss. « Laboratory-Developed Tests : A Legislative and Regulatory Review ». Clinical Chemistry 63, n^o 10 (1 octobre 2017) : 1575–84. http://dx.doi.org/10.1373/clinchem.2017.275164.

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Abstract BACKGROUND Twenty-five years ago, the Food and Drug Administration (FDA) asserted in a draft document that “home brew” tests—now commonly referred to as laboratory-developed tests (LDTs)—are subject to the same regulatory oversight as other in vitro diagnostics (IVDs)4. In 2010, the FDA began work on developing a proposed framework for future LDT oversight. Released in 2014, the draft guidance sparked an intense debate over potential LDT regulation. While the proposed guidance has not been implemented, many questions regarding LDT oversight remain unresolved. CONTENT This review provides an overview of federal statutes and regulations related to IVDs and clinical laboratory operations, with a focus on those potentially applicable to LDTs and proposed regulatory efforts. Sources reviewed include the Code of Federal Regulations, the Federal Register, congressional hearings, guidance and policy documents, position statements, published literature, and websites. SUMMARY Federal statutes regarding IVDs were passed without substantive evidence of congressional consideration toward the concept of LDTs. The FDA has clear oversight authority over IVD reagents introduced into interstate commerce. A 16-year delay in publicly asserting FDA authority over LDTs, the pursuit of a draft guidance approach toward oversight, and establishment of regulations under the Clinical Laboratory Improvement Amendments of 1988 (CLIA'88) applicable to LDTs contributed to community uncertainty toward LDT oversight. Future regulatory and/or legislative efforts may be required to resolve this uncertainty.

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Lichtenberg, Steven, Oxana P. Trifonova, Dmitry L. Maslov, Elena E. Balashova et Petr G. Lokhov. « Metabolomic Laboratory-Developed Tests : Current Status and Perspectives ». Metabolites 11, n^o 7 (26 juin 2021) : 423. http://dx.doi.org/10.3390/metabo11070423.

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Laboratory-developed tests (LDTs) are a subset of in vitro diagnostic devices, which the US Food and Drug Administration defines as “tests that are manufactured by and used within a single laboratory”. The review describes the emergence and history of LDTs. The current state and development prospects of LDTs based on metabolomics are analyzed. By comparing LDTs with the scientific metabolomics study of human bio samples, the characteristic features of metabolomic LDT are shown, revealing its essence, strengths, and limitations. The possibilities for further developments and scaling of metabolomic LDTs and their potential significance for healthcare are discussed. The legal aspects of LDT regulation in the United States, European Union, and Singapore, demonstrating different approaches to this issue, are also provided. Based on the data presented in the review, recommendations were made on the feasibility and ways of further introducing metabolomic LDTs into practice.

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Skedros, John G., et Tanner R. Henrie. « Latissimus Dorsi Tendon Transfer with GraftJacket® Augmentation to Increase Tendon Length for an Irreparable Rotator Cuff Tear ». Case Reports in Orthopedics 2017 (2017) : 1–6. http://dx.doi.org/10.1155/2017/8086065.

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Massive irreparable rotator cuff tears can be reconstructed with latissimus dorsi tendon transfers (LDTT). Although uncommon, the natural length of the latissimus dorsi tendon (LDT) could be insufficient for transfer even after adequate soft tissue releases. Descriptions of cases where grafts were needed to lengthen the LDT are therefore rare. We located only two reports of the use of an acellular dermal matrix to increase effective tendon length in tendon transfers about the shoulder: (1) GraftJacket patch for a pectoralis major tendon reconstruction and (2) ArthroFlex® patch for LDTT. Both of these brands of allograft patches are obtained from human cadavers. These products are usually used to cover soft tissue repairs and offer supplemental support rather than for increasing tendon length. Extending the LDTT with GraftJacket to achieve adequate length, to our knowledge, has not been reported in the literature. We report the case of a 50-year-old male who had a massive, irreparable left shoulder rotator cuff tear that was reconstructed with a LDTT. The natural length of his LDT was insufficient for transfer. This unexpected situation was rectified by sewing two patches of GraftJacket to the LDT. The patient had greatly improved shoulder function at two-year follow-up.

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Gu, Henan, Jian Luo, Guofang Li, Yueling Yao, Yan Huang et Dongjing Huang. « Spatial-Temporal Variations of Active Accumulated Temperature and Its Impact on Vegetation NDVI in the Source Region of China’s Yellow River ». Water 14, n^o 21 (29 octobre 2022) : 3458. http://dx.doi.org/10.3390/w14213458.

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Global climate change has greatly influenced the ecosystems in the Tibetan Plateau. Many studies focused on the direct effects of climate warming on the headwater regions by mean temperature, while less investigating its implication for the eco-environment. To address this, the study discussed the spatial-temporal variations of the bio-related climate indicators ≥0 °C annual accumulated temperature AAT0 and its lasting days LDT0, and corresponding ≥5 °C indicators AAT5 and LDT5 on the source region of the Yellow River (SRYR). The stationarity of indicators during 1979–2018 were tested by Pettitt test, and trends checked by linear regression analysis and Mann-Kendall test. Normalized difference vegetation index NDVI (2001–2016) was adopted to detect the correlation between vegetation activities and indicators. Results show that the AAT and LDT0 exhibited significant increasing trend over the SRYR, while the LDT5 significantly increased mainly under 4000 m. Most LDT extended due to the combined efforts of the early onset and late termination of the given temperature. 1997 was detected in the abrupt change analysis of AAT0 both on the basin scale and most area, and was adopted to divide the period into two stages. The regional mean AAT0 linearly grew at a rate of 96 °C decade−1 during the entire period, and 104 °C decade−1 during the second stage. Except for a drastic jump in the areal mean values, there was a distinct upward-shift of isoline in elevation between stages. NDVI showed strong correlativity with ≥0 °C indicators on the basin scale, according to the Pearson, Spearman and Kendall correlation coefficients, ranging from 0.5 to 0.7. Spatially, the overlap area between Pearson’s γ ≥ 0.5 and linearly rising AAT0 reached 50%, which was fully covered with significantly increasing AAT0 during the recent stage. Thus the rapid growth of ≥0 °C indicators would effectively accelerate NDVI over this major alpine grasslands, especially around the eastern low regions, where indicators are higher and grow faster.

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Stiggins, Chuck, et Dr Phil Allsen. « EXERCISE METHODS NOTEBOOK #30 : Lying dumbbell triceps extension ». National Strength & ; Conditioning Association Journal 9, n^o 3 (1987) : 79. http://dx.doi.org/10.1519/0744-0049(1987)009<0079:ldte>2.3.co;2.

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Vermeersch, Pieter, Tobias Van Aelst et Elisabeth M. C. Dequeker. « The new IVD Regulation 2017/746 : a case study at a large university hospital laboratory in Belgium demonstrates the need for clarification on the degrees of freedom laboratories have to use lab-developed tests to improve patient care ». Clinical Chemistry and Laboratory Medicine (CCLM) 59, n^o 1 (26 janvier 2021) : 101–6. http://dx.doi.org/10.1515/cclm-2020-0804.

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AbstractObjectivesThe new European In Vitro Diagnostic (IVD) Regulation 2017/746 (IVDR) restricts the use of lab-developed tests (LDT) after 26th May 2022. There are no data on the impact of the IVDR on laboratories in the European Union.MethodsLaboratory tests performed in UZ Leuven were divided in four groups: core laboratory, immunology, special chemistry, and molecular microbiology testing. Each test was classified as Conformité Européenne (CE)-IVD, modified/off-label CE-IVD, commercial Research Use Only (RUO) or LDT. Each matrix was considered a separate test.ResultsWe found that 97.6% of the more than 11.5 million results/year were generated with a CE-IVD method. Of the 922 different laboratory tests, however, only 41.8% were CE-IVD, 10.8% modified/off-label CE-IVD, 0.3% RUO, and 47.1% LDT. Off-label CE-IVD was mainly used to test alternative matrices not covered by the claim of the manufacturer (e.g., pleural or peritoneal fluid). LDTs were mainly used for special chemistry, flow cytometry, and molecular testing. Excluding flow cytometry, the main reasons for the use of 377 LDTs were lack of a CE-IVD method (71.9%), analytical requirements (14.3%), and the fact the LDT was in use before CE-IVD available (11.9%).ConclusionsWhile the large majority of results (97.6%) were generated with a CE-IVD method, only 41.8% of laboratory tests were CE-IVD. There is currently no alternative on the market for 71.5% of the 537 LDTs performed in our laboratory which do not fall within the scope of the current IVD directive (IVDD). Compliance with the IVDR will require a major investment of time and effort.

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DE JESÚS, ANTONIO J., et RICHARD C. WHITING. « Modeling the Physiological State of the Inoculum and CO2 Atmosphere on the Lag Phase and Growth Rate of Listeria monocytogenes ». Journal of Food Protection 71, n^o 9 (1 septembre 2008) : 1915–18. http://dx.doi.org/10.4315/0362-028x-71.9.1915.

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In previous studies, the growth of L. monocytogenes has been modeled under different CO2 headspace concentrations; however, the inoculum cells were always in the stationary phase. In this study, the growth of L. monocytogenes under different CO2 concentrations as affected by the physiological state of the cells was investigated. Exponential-growth-phase, stationary-phase, dried, and starved cells were prepared and inoculated at 5°C into brain heart infusion broths that had been preequilibrated under atmospheres of 0, 20, 40, 60, or 80% CO2 (the balance was N2). Lag-phase duration times (LDTs) and exponential growth rates were determined by enumerating cells at appropriate time intervals and by fitting the data to a three-phase linear function that has a lag period before the initiation of exponential growth. Longer LDTs were observed as the CO2 concentration increased, with no growth observed at 80% CO2. For example, the LDTs for exponential-phase, stationary-phase, starved, and dried cells were 2.21, 8.27, 9.17, and 9.67 days, respectively, under the 40% CO2 atmosphere. In general, exponential-growth-phase cells had the shortest LDT followed by starved cells and stationary-phase cells. Dried cells had the longest LDT. Exponential growth rates decreased as the CO2 concentrations increased. Once exponential growth was attained, no retained differences among the various initial physiological states of the cells for any of the atmospheres were observed in the exponential growth rates. The exponential growth rates under 0, 20, 40, 60, and 80% CO2 averaged 0.39, 0.37, 0.23, 0.23, and 0.0 log CFU/day, respectively. Dimensionless factors were calculated that describe the inhibitory action of CO2 on the LDTs and exponential growth rates for the various physiological states.

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Thèses sur le sujet "LdtE"

MORÈ, NICCOLÒ. « Lipopolysaccharide transport and peptidoglycan remodeling : two related processes in Escherichia coli ». Doctoral thesis, Università degli Studi di Milano-Bicocca, 2018. http://hdl.handle.net/10281/198942.

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Il rivestimento dei batteri Gram negativi consiste in una membrana interna (IM) e una membrana esterna (OM) separate da uno spazio periplasmatico contenente un sottile strato di peptidoglicano (PG) ancorato alla OM tramite la lipoproteina di Braun (LPP). Mentre la IM è costituita da un doppio strato di fosfolipidi, la OM è una membrana lipidica asimmetrica, contenente fosfolipidi nel foglietto interno, e un lipide complesso il Lipopolisaccaride (LPS) nel foglietto esterno. Il LPS sintetizzato nel citoplasma, viene traslocato sul lato periplasmatico della IM e preso in carico dal complesso multiproteico Lpt (LPS transport), composto in Escherichia coli da sette proteine essenziali (Lpt ABCDEFG) che si occupano del suo trasporto fino al raggiungimento della sua sede finale, la OM. Analisi biochimiche hanno dimostrato che le sette proteine Lpt formano un complesso “transenvelope” che connette IM e OM e studi di tipo genetico suggeriscono che esse operino in concerto come un singolo macchinario. Infatti, la deplezione di un qualsiasi componente del complesso Lpt causa lo stesso fenotipo, ovvero l’accumulo del LPS nel versante periplasmatico della IM, la decorazione del LPS con acido colanico e la formazione di una IM anomala, con una densità intermedia tra la IM e la OM. Nel nostro laboratorio è stata condotta l’analisi differenziale del proteoma delle membrane totali di E. coli in deplezione di LptC, per studiare la risposta globale al blocco del trasporto del LPS. Tra le proteine il cui livello cambia nel confronto tra il ceppo non depleto e il depleto sono state trovate proteine coinvolte nella biogenesi e nel rimodellamento del PG. Lo scopo di questa tesi è stato lo studio della correlazione tra il blocco del LPS e il rimodellamento del PG. Inizialmente è stata analizzata la struttura del PG in deplezione di LptC. Questa analisi ha evidenziato che in questa condizione la struttura del PG varia sia per composizione che per tipo di legami crociati tra i filamenti glicanici adiacenti. Nei batteri Gram negativi il legame tra i filamenti glicanici è generalmente un legame diretto 3-4, che si forma tra il gruppo aminico del diaminoacido in posizione 3 di un tetrapeptide e il gruppo carbossilico della D-alanina in posizione 4 del tretrapeptide adiacente. Il legame 3-4 avviene ad opera delle D,D transpeptidasi PBP. Un altro tipo di legame crociato presente nel PG è quello tipo 3-3 che si forma tra il gruppo aminico del diaminoacido in posizione 3 ed il gruppo carbossilico del diaminoacido presente nel tetrapeptide del filamento glicanico adiacente ed è catalizzato da L,D-transpeptidasi . In E. coli, sono noti cinque enzimi con attività L,D-transpeptidasica, di cui tre (LdtA, LdtB, LdtC) ancorano la lipoproteina più abbondante della OM (lipoproteina di Braun) al PG e due (LdtD, LdtE) catalizzano il legame crociato 3-3. La delezione di tutti questi geni, singolarmente o in combinazione, non presenta nessun fenotipo, suggerendo che in condizioni normali questo legame è dispensabile. Per studiare la correlazione tra il legame crociato 3-3 e il blocco del trasporto del LPS abbiamo creato mutanti arabinosio dipendenti per alcuni dei componenti del sistema Lpt deleti contemporaneamente per i geni che esprimono le L,D-transpeptidasi LdtD e LdtE. In precedenza, nel nostro laboratorio è stato dimostrato che la deplezione di uno qualsiasi dei geni lpt causa la formazione di cellule filamentose e l’arresto della crescita ma non la lisi cellulare. Invece, nei mutanti ΔldtDΔldtE, in deplezione dei geni lpt, oltre alla formazione di cellule filamentose si osserva la formazione di un setto anomalo e la lisi cellulare. Questi dati suggeriscono che il rimodellamento del peptidoglicano a seguito della formazione di legami 3-3 potrebbe essere una forma di riposta al danno alla membrana esterna.
The cell envelope of Gram-negative bacteria is a complex multi-layered structure consisting of a cytoplasmic and an outer membrane (CM and OM), which delimit the periplasm containing a thin layer of peptidoglycan (PG) called the sacculus. The primary function of the OM is to establish a selective permeability barrier that enables the cell to maintain favourable intracellular conditions even in hash environments and the lipopolysaccharide (LPS) layer greatly contributes to this peculiar property. The integrity of the PG mesh is essential to protect the cell from bursting due to its turgor and maintain the shape of the cell. OM and PG are synthetized and assembled by multiprotein machineries that need to be finely coordinated as imbalanced growth of these layers may compromise structural integrity of the cell. In order to gain more insight in the mechanism by which the cells coordinate the growth of these two layers, we analysed the PG composition when the biogenesis of OM is compromised due to the block of LPS transport. In this work we shown that when OM is impaired, E. coli cells remodel PG architecture by increasing the non-canonical 3- 3 cross-linkage. We can assume that this is a salvage mechanism to prevent cell lysis when OM is damaged.

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Mizutani, Teruyoshi, Kenta Shinmura, Kazue Kaneko, Tatsuo Mori, Mitsugu Ishioka et Tatsuya Nagata. « Space Charge Behavior near LDPE / LDPE Interface ». IEEE, 2000. http://hdl.handle.net/2237/7162.

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Cömert, Engin. « Utvärdering av karboniserad LDPE som egenskapsförbättrande tillsats i nya LDPE-filmer ». Thesis, KTH, Skolan för kemi, bioteknologi och hälsa (CBH), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-240303.

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Tidigare forskning har visat att med hjälp av en speciell mikrovågsugn så kan man omvandla lågdensitetspolyeten (LDPE) till kemikalier med högre värde [1]. Ett försök på att omvandla plastavfall (LDPE) till en produkt med högre värde kommer att göras i detta projekt. Att kunna återvinna plast är en fråga som under de senaste åren har växt och fortsätter växa, i dagsläget så finns det ett intresse att kunna producera nya produkter från återvunnet material [2]. Eftersom plaster succesivt förlorar sina egenskaper varje gång de värms upp så är det ofta enklare för ett företag att skapa och använda ny plast. Plast som kan ha förlorat sina mekaniska egenskaper eller eventuellt har förorenats är inte något som efterfrågas [3] [4]. Kolprickar är ett slags nanomaterial som har fascinerande egenskaper och som börjats forska mer och mer om under de senaste 10 åren. Under detta projekt kommer det stora fokus ligga på om man kan tillverka denna typ av partiklar genom karbonisering av LDPE och hur tillsats av denna typ av partiklar påverkar de mekaniska egenskaperna hos nya LDPE produkter [5]. Under detta projekt användes en speciell mikrovågsugn för karbonisering av polyeten, genom användning av mikrovågsugnen med salpetersyra och saltsyra som katalysatorer så kunde man syntetisera fram dispergerade partiklar (DP) och fasta partiklar (FP) från LDPE. Dispergerade partiklarnas och fasta partiklarnas strukturella egenskaper analyserades genom användning av FT-IR och XRD. Analys av partikelstorlek för dispergerade partiklarna gjordes genom DLS och morfologi undersöktes med SEM. I detta projekt visades det att man hade lyckats ändra polyetenets strukturella egenskaper då nya grupper kunde ses på FT-IR och XRD. Partikelstorleken mättes också och man kom fram till att det var grova partiklar som bildades och att de inte var så homogena. Tillverkning av kompositfilmer innehållande dispergerade partiklar och fasta partiklar lyckades man också åstadkomma. Kompositerna bestod av 0,5 vikt-% DP som blandades med 99,5 vikt-% LDPE pulver. En annan komposit gjordes också fast här ökade man viktsprocenten av partiklar till 2,5 vikt-% DP som blandades med 97,5 vikt-% LDPE pulver. Kompositerna innehållande FP skapades genom att blanda 5 vikt-% och 10 vikt-% FP med 95 vikt-% och 90 vikt-% LDPE pulver. Filmernas mekaniska egenskaper analyserades genom dragprovning, resultaten visade sig att dragspänningen för kompositfilmerna innehållande DP gav ett styvare material än filmen med endast LDPE. Kompositfilmerna med FP fick däremot ett mycket högre modulus än dem andra, materialet hade alltså blivit mycket styvare och en stor del av flexibiliteten hade gått förlorad. Slutsatsen man kunde komma fram till var att metoden kan användas för att skapa ett material som är starkare och mer styvt.
Previous research has shown that with the assistance of a specially formed microwave oven you can degrade low density polyethylene (LDPE) to chemicals with more value, so this project will try to reform plastic waste (LDPE) to a product with more value. Being able to recycle plastic is a question that has grown these past years and is still growing. As things stand there is an interest in being able to produce plastics that can be recycled. Because plastics lose some of their mechanical properties every time they are heated the companies who produce them find it easier and cheaper to just use new plastic. Therefore, to be able to produce a plastic which does not lose its mechanical properties is something that is being strived for. Carbon dots is a new kind of nanomaterial that has fascinating properties and research on it and its properties has been done during the last 10 years. During this project the main focus will therefore be to evaluate whether LDPE can be carbonized to carbon dot like materials and whether addition of these affects the mechanical properties of new LDPE products. By using the special microwave, the synthesis of carbon dots was successful. In addition, solid particles we gained from LDPE. The structural properties of the carbon dots and solid particles were analysed by using FT-IR, NMR and XRD. There was also an analysis on the particle sizes which was done by using DLS and morphological evaluation which was performed by SEM. The synthesized particles were also put into TGA to evaluate their thermal stability. The synthesis was successful, and you could see a change in the particles structure because new functional groups could be found by using FT-IR, NMR and XRD. The particle size was also measured, and the consensus was that the particles were coarse and not that homogenous. Making of the composites with the carbon dots and solid particles is also something that was successfully done. The composites contained 0.5 wt-% of synthesized carbon dots and 99.5 wt-% of LDPE powder and another one where 2.5 wt-% of synthesized carbon dots was mixed with 97.5 wt-% of LDPE powder. The solid particle composites were created by mixing 5 wt-% and 10 wt-% solid particles mixed with 95 wt-% and 90 wt-% of LDPE powder. The mechanical properties were analysed with a tensile testing machine, the result that was retrieved from the machine was that the films made of the composites with DP gave a stiffer material than the film made only by LDPE. The composite films with FP gave a much higher modulus than the other films made by addition of DP. The results show that the films with FP were also a lot stiffer than the film with only LDPE. The conclusion is that you can use this method to create a material that is stronger and stiffer.

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Steffl, Thomas. « Rheological and film blowing properties of various low density polyethylenes and their blends ». [S.l.] : [s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=972028625.

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Olyveira, Gabriel Molina de. « Preparação e caracterização de nanocompósitos de LDPE e LDPE/EVA com partículas de Ag/TIO2 para aplicações antimicrobiais ». Universidade Federal de São Carlos, 2009. https://repositorio.ufscar.br/handle/ufscar/854.

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Universidade Federal de Sao Carlos
This study investigated the use of a charger inorganic (titanium dioxide) as a support for silver nanoparticles and evaluated the use of material obtained as filler in polymer for antimicrobial application.Silver nanoparticles-titanium dioxide were synthesized by the reduction method developed by Turkevich, also known as a method of citrate. Therefore, we used three different types of titanium dioxide in the colloidal synthesis and found that nanometer titanium dioxide showed better results for the deposition of silver nanoparticles. Silver Nitrate was reduced by sodium citrate with and without the presence of a surfactant (PVP-Polyvinylpyrrolidone) resulting in a stable suspension of nanoparticles of silver / titanium dioxide. We also tested NH4OH (ammonium hydroxide) to prevent the growth of nanoparticles during the reaction. Nanocomposite of LDPE and LDPE / EVA were produced by mixing in the molten state with the Ag nanoparticles-titanium dioxide resulting from the colloidal synthesis. By assessing the rheological, thermal and morphological analysis we found that compared with nanocomposite LDPE / EVA, LDPE nanocomposite showed better results with regard to dispersion of the charges, but nanocomposite LDPE / EVA showed better results in antimicrobial assays due to the polar nature the grouping of EVA able to bind more easily to inorganic fillers.
Neste trabalho foi estudada a utilização de um carregador inorgânico (dióxido de titânio) como suporte para as nanopartículas de prata e avaliado o uso do material obtido como carga em polímeros para aplicação antimicrobial. Nanopartículas de prata-dióxido de titânio foram sintetizadas pelo método de redução desenvolvido por Turkevich, também conhecido como método do citrato. Para tanto foram utilizados 3 diferentes tipos de dióxido de titânio na síntese coloidal e verificou-se que os dióxidos de titânio na forma nanométrica apresentaram melhores resultados quanto a deposição das nanopartículas de prata. O Sal de Prata (Nitrato de Prata) foi reduzido pelo citrato de sódio sem e com a presença de um surfactante (PVP- Polivinilpirrolidona) resultando numa suspensão estabilizada de nanopartículas de prata / dióxido de titânio. Foi testado também a presença de um agente moderador da reação, NH4OH (hidróxido de amônia), para evitar o crescimento das nanopartículas durante a reação. Os nanocompósitos de LDPE e LDPE/EVA foram produzidos através da mistura no estado fundido com as nanopartículas de Ag- dióxido de titânio resultantes da síntese coloidal. Através das análises reológicas, térmicas e morfológicas constatou-se que em comparação com o nanocompósito LDPE/EVA, o nanocompósito com LDPE apresentou resultados melhores quanto a dispersão das cargas, porém o nanocompósito LDPE/EVA apresentou melhores resultados nos ensaios antimicrobiais devido a natureza polar do grupamento do EVA capaz de se ligar mais facilmente às cargas inorgânicas.

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Riess, Katrin. « Plasmamodifizierung von Polyethylen ». [S.l. : s.n.], 2001. http://deposit.ddb.de/cgi-bin/dokserv?idn=961745886.

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Andersen, Bistra. « Investigations on environmental stress cracking resistance of LDPE/EVA blends ». [S.l. : s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=972520481.

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Hendry, Benjamin H. « Evaluation of post-residential LDPE recycling in Georgia ». Thesis, Georgia Institute of Technology, 1991. http://hdl.handle.net/1853/28817.

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Chalapati, Sachin. « Toluene Mediated FCC of LDPE Using Ionic liquids ». Thesis, Högskolan i Borås, Institutionen Ingenjörshögskolan, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-17973.

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Polyethylene is one of the most widely used synthetic materials produced by mankind and its accumulation in the biosphere is exceeding at an alarming rate. There are several methods to recycle or remediate the waste polyethene apart from land filling and generation of useful products from the waste is on demand for research and development. Ionic liquids are aggressively replacing several organic compounds due to their robust nature and also have novel properties that allow depolymerization of synthetic materials into simpler short chained paraffins. Initial dissolution of polymer using hot toluene followed by agitated depolymerization using EMIM-Cl (AlCl3) ionic liquid for producing fuel grade high calorie organic molecules might be proven successful. This method uses proton sources like sulphuric acid, hydrochloric acid or waters that aid saturation of organic compounds by hydrogen ion exchange. This could be a novel procedure that aims to produce fuel grade products from waste synthetic polymers like polyethene.
Program: Master of Science with a Major in Resource recovery – Industrial biotechnology

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Rabie, Allan John. « Blends with low-density polyethylene (LDPE) and plastomers ». Thesis, Stellenbosch : Stellenbosch University, 2004. http://hdl.handle.net/10019.1/49870.

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Thesis (MSc)--Stellenbosch University, 2004.
ENGLISH ABSTRACT: This study describes the design, building and optimization of a fully functional preparative TREF (Prep-TREF) apparatus. This apparatus allows for the fractionation of semicrystalline polyolefins according to the crystallizability of the molecules. Various factors, such as the sample cooling rate and the effect of on-support and off-support crystallization, are investigated. The preparative TREF is used to fractionate a commercial low-density polyethylene (LOPE), two commercially available plastomers (polyethylene-l-octene copolymers), as well as blends of the LOPE and the respective plastomers. It is shown that in each case the samples fractionated by crystallizability. The fractions recovered from the Prep-TREF were characterized by CRYSTAF, OSC and NMR analysis. It is shown how the results of this preparative fractionation allow for a better understanding of the molecular heterogeneity in the LOPE and plastomers. New ways of presenting the data from the preparative fractionation, in terms of 3- dimensional plots, are also investigated. These plots offer a novel way of presenting the molecular heterogeneity in the samples in terms of the molecular crystallizability. These plots highlight features that are difficult to detect in the conventional two-dimensional plots. In conclusion, the influences of various blending ratios of LOPE and plastomer on the morphological and physical properties of the blends, such as haze, clarity, and tear-and impact strength are determined.
AFRIKAANSE OPSOMMING: Die doel van hierdie studie was die ontwikkeling en optimisering van 'n ten volle funksionerende TREF. Hierdie tegniek word gebruik om polimeermengsels te fraksioneer deur gebruik te maak van die kristaliseerbaarheid van polimere. Verskeie faktore soos die afkoel spoed en die effect van met en sonder 'n ondersteuning(seesand) vir kristaliseering was ondersoek. Hierna is navorsing gedoen om 'n beter begrip ten opsigte van die meganiese, fisiese en optiese eienskappe van lae-digtheid poliëtileen (LDPE) te ontwikkel. Hierdie LDPE is met die affiniteitsreeks plastomere van die maatskappy, Dow Chemicals, gemeng om tendense in die gefraksioneerde polimere te indentifiseer. Een van Sasol se kommersiële LDPE produkte en twee van Dow Chemicals se plastomere is individueel gefraksioneer. Die mengsel van die twee ongefraksioneerde LDPE en plastomere is nog nooit voorheen op 'n molekulêre basis ondersoek nie. Dit is in hierdie studie gedoen deur van TREF gebruik te maak. Nuwe maniere is ontwikkel om data op 'n nuwe manier voor te stel deur middel van 3 Dimensionele grafieke te skep om resultate voor te stel wat andersins baie moelilik was om voor te stel in een dimensie agv die hoeveelheid data wat geinterpreteer word. Ten slotte is die invloed van die verskillende mengverhoudings van LDPE en plastomere op die morfologiese en fisiese eienskappe soos deursigtigheid, helderheid, skeur- en impaksterkte, ook ondersoek.

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Livres sur le sujet "LdtE"

Klaus Edel Galerie (Ko ln), dir. Ausstellung Gema lde alter Meister : Gema lde alter Meister. Ko ln : Klaus Edel Galerie, 1987.

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Rigs lam ʼphrul lde. Lan-chou : Kan-suʼu mi rigs dpe skrun khȧn, 2005.

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Library of Tibetan Works & Archives, dir. Gser gyi lde mig. Dharamsala : Bod-kyi Dpe-mdzod-khang, 2018.

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nau, Hans Wolfsbauer-Scho. Salzburg : Gema lde und Grafiken. Wien : Springer, 2009.

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Odén, Birgitta. De a ̈ldre i samhället, förr : Fem föreläsningar. Lund : B. Odén, 1985.

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Karma-don-grub-dpal-ldan-bsod-nams-dbaṅ-phyug-tshe-riṅ-rnam-par-rgyal-baʼi-lha. Man ngag lhan thabs kyi lde mig ; Zin tig bdud rtsi thigs paʼi lde mig. Pe-cin : Mi-rigs Dpe-skrun-khang, 2008.

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Smyon-pa-jo-dar. Rdzong ʼphrang ʼphrul gyi lde mig. Pe-cin : Mi rigs dpe-skrun-khang, 2019.

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Fussmann, Klaus. Ansichten : Gema lde, Gouachen, Aquarelle 1968-1992. Bremen : Kunsthalle Bremen, 1992.

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"Bod kyi gso ba rig paʼi gnaʼ dpe phyogs bsgrigs" rtsom sgrig tshogs pa et Min zu chu ban she, dir. Man ṅag lhan thabs daṅ lde mig. Pe-cin : Mi rigs dpe skrun khaṅ, 2005.

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Mahapatro, A. Crosslinking and foaming behaviour of low density polythene foams (LDPE). Manchester : UMIST, 1997.

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Chapitres de livres sur le sujet "LdtE"

Gooch, Jan W. « LDPE ». Dans Encyclopedic Dictionary of Polymers, 422. New York, NY : Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4419-6247-8_6822.

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Zhong, Maiying, Ting Xue, Steven X. Ding et Donghua Zhou. « LDTV Systems and Fault Detection and Estimation for LDTV Systems ». Dans Fault Diagnosis for Linear Discrete Time-Varying Systems and Its Applications, 31–47. Singapore : Springer Nature Singapore, 2022. http://dx.doi.org/10.1007/978-981-19-5438-2_3.

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Ahlheim, Michael. « Ökosteuern - ldee und Wirklichkeit ». Dans Integriertes Steuer- und Sozialsystem, 242–67. Heidelberg : Physica-Verlag HD, 2003. http://dx.doi.org/10.1007/978-3-642-57376-7_12.

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Bashford, David. « Low Density Polyethylene (LDPE) ». Dans Thermoplastics, 143–47. Dordrecht : Springer Netherlands, 1997. http://dx.doi.org/10.1007/978-94-009-1531-2_15.

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Zhong, Maiying, Ting Xue, Steven X. Ding et Donghua Zhou. « Optimal Fault Detection for LDTV Systems ». Dans Fault Diagnosis for Linear Discrete Time-Varying Systems and Its Applications, 89–103. Singapore : Springer Nature Singapore, 2022. http://dx.doi.org/10.1007/978-981-19-5438-2_6.

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Trabelsi, Mounir, et Ali Triki. « Water-Hammer Control in Pressurized Pipe Flow Using Dual (LDPE/LDPE) Inline Plastic Sub Short-Sections ». Dans Lecture Notes in Mechanical Engineering, 953–61. Cham : Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-27146-6_102.

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Belov, Alexey A., Olga G. Andrianova et Alexander P. Kurdyukov. « Anisotropy-Based Analysis of LDTI Descriptor Systems ». Dans Control of Discrete-Time Descriptor Systems, 61–97. Cham : Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-78479-3_3.

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Zhong, Maiying, Ting Xue, Steven X. Ding et Donghua Zhou. « Parity Space-Based Fault Estimation for LDTV Systems ». Dans Fault Diagnosis for Linear Discrete Time-Varying Systems and Its Applications, 227–38. Singapore : Springer Nature Singapore, 2022. http://dx.doi.org/10.1007/978-981-19-5438-2_15.

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Witte, Bernd. « Von der allegorischen Lektüre zur ldee der “integralen Prosa” ». Dans »Magnetisches Hingezogensein oder Schaudernde Abwehr«, 95–121. Stuttgart : J.B. Metzler, 1994. http://dx.doi.org/10.1007/978-3-476-03534-9_5.

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Majeed, Khaliq, Reza Arjmandi et Azman Hassan. « LDPE/RH/MAPE/MMT Nanocomposite Films for Packaging Applications ». Dans Bionanocomposites for Packaging Applications, 209–25. Cham : Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-67319-6_11.

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Actes de conférences sur le sujet "LdtE"

Al-Gunaid, Taghreed Abdulhameed, Anton Popelka et Igor Krupa. « Enhancement of Adhesion Characteristics of Low-density Polyethylene using Atmospheric Plasma Initiated-Grafting of Polyethylene Glycol ». Dans Qatar University Annual Research Forum & Exhibition. Qatar University Press, 2021. http://dx.doi.org/10.29117/quarfe.2021.0056.

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The low-density polyethylene/aluminum (LDPE/Al) joint in Tetra Pak food container provides stability and strength to food packaging, ensures protection against outside moisture, and maintains the nutritional values and flavors of food without the need for additives in the food products. However, it was found that the adhesion strength of LDPE with Al is weak or almost non-existent, due to the non-polar hydrophobic LDPE surface. Therefore, it was necessary to apply surface treatment to LDPE. Plasma-assisted grafting of the LDPE surface with different molecular weight compounds of polyethylene glycol (PEG) was used to improve LDPE/Al adhesion. It was found that this surface modification contributed to significantly improve the wettability of the LDPE surface, as was confirmed by contact angle measurements. The chemical composition changes after plasma treatment and modification process was observed by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). A surface morphology was analyzed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Adhesion characteristics of LDPE/Al adhesive joints were analyzed by the peel tests. The most significant adhesion improvement of the PEG modified LDPE surface was achieved using 10.0 wt.% aqueous (6000 M) PEG solution, while the peel resistance increased by approximately 54 times in comparison with untreated LDPE.

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Al-Gunaid, Taghreed Abdulhameed, et Anton Popelka. « Adhesion Improvement between Polyethylene and Aluminium using Eco-Friendly Plasma Treatment ». Dans Qatar University Annual Research Forum & Exhibition. Qatar University Press, 2020. http://dx.doi.org/10.29117/quarfe.2020.0060.

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Lamina made of low density polyethylene (LDPE) and Aluminium (Al) is used widely in many applications, especially in food packaging (TetraPak containers). However, it's found that the adhesive bond between LDPE-Al is low due to the hydrophobic surface of LDPE. Therefore, there is a strongly need for surface modification of LDPE. Corona discharge, which is considered as an atmospheric pressure plasma technique was used in this research to treat LDPE surface by adding polar functional groups (e.g. hydroxyl, carbonyl, and carboxyl groups) into the exposed non-polar surface which led to increase surface free energy and then greater wettability and a smaller contact angle, and finally the adhesion between LDPE-Al improved significantly.

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Johnstone, Adrian, Elizabeth Scott et Mark van den Brand. « LDT ». Dans the Eleventh Workshop. New York, New York, USA : ACM Press, 2011. http://dx.doi.org/10.1145/1988783.1988792.

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Zhao, Ni, Shengtao Li, Xia Wang et Guochang Li. « Effects of LDPE/nanofilled LDPE interface on space charge formation ». Dans 2013 IEEE International Conference on Solid Dielectrics (ICSD). IEEE, 2013. http://dx.doi.org/10.1109/icsd.2013.6619862.

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Khan, Mujibur R., Hassan Mahfuz et Andreas Kyriacou. « Synthesis and Characterization of Low Density Polyethylene (LDPE) Reinforced With Functionalized CNTs ». Dans ASME 2008 International Mechanical Engineering Congress and Exposition. ASMEDC, 2008. http://dx.doi.org/10.1115/imece2008-68034.

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A systematic approach was undertaken to increase strength, modulus, and toughness of low density polyethylene (LDPE) filaments through infusion of functionalized CNT and ultra high molecular weight polyethylene (UHMWPE). CNTs were functionalized with OH functional groups using chemical treatment. Functionalized CNTs and UHMWPE were first dry mixed with LDPE, and filaments were then drawn using a melt extrusion process. Loading of UHMWPE varied from 8–10 wt% while that of CNT was at 2–4 wt%. LDPE has been infused first with UHMWPE, and then with both UHMWPE and CNT, and filaments were extruded. Neat LDPE filaments were also extruded as control samples. Individual filaments from each category were tested under tension according to ASTM D3379-75. In addition, differential scanning calorimetry (DSC) and X-ray diffraction (XRD) studies were also conducted to measure changes in thermal and crystalline behavior. Filament tests have revealed that the tensile elongation of LDPE can be increased by about 200% with the addition of 10 wt% UHMWPE. This is however, is accompanied by a loss of about 50% ultimate tensile strength. In the next step, when 2 wt% CNTs and 8 wt% UHMWPE are added, tensile strength of the composite filament is restored to the level of neat LDPE (∼ 25 MPa) with an increase in modulus by 44% and in ultimate fracture strain by about 60% compared to that of neat LDPE. The source of improvement has been traced as formation of copolymer between LDPE and UHMWPE and strong interfacial interaction between the CNT and the polymers.

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Rizvi, Reza, et Hani Naguib. « Synthesis and Characterization of LDPE-Carbon Nanotube Composite Foams ». Dans ASME 2008 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. ASMEDC, 2008. http://dx.doi.org/10.1115/smasis2008-444.

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This study details the synthesis and characterization of composites and composite foams of low-density polyethylene (LDPE) and multi-walled carbon nanotubes (MWCNT). LDPE-MWCNT composites were prepared by melt blending the components in a twin screw compounder and their foams were produced by batch foaming using CO2 as the blowing agent. The composites were characterized for dispersion using SEM and image results indicate good dispersability of MWCNT in LDPE with the formation of a MWCNT network in the LDPE matrix. Thermal and rheological properties of the composites were characterized and results indicate that even a small amount (1 wt.%) of MWCNTs can significantly affect the crystallization kinetics and the rheological behavior. Batch foaming results of the composites depict MWCNTs as heterogeneous nucleation sites for gas bubbles as indicated by the increase in cell density of the composite foams when compared to LDPE foams.

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Stan, Felicia, Nicoleta-Violeta Stanciu, Catalin Fetecau et Ionut-Laurentiu Sandu. « Mechanical Recycling of Low-Density Polyethylene/Carbon Nanotube Composites and its Effect on Material Properties ». Dans ASME 2019 14th International Manufacturing Science and Engineering Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/msec2019-2929.

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Abstract In this paper, the impact of recycling and remanufacturing on the behavior of low-density polyethylene/multi-walled carbon nanotube (LDPE/MWCNT) composites is investigated. LDPE/MWCNT composites with 0.1–5 wt.%, previously manufactured by injection molding, were mechanically recycled and remanufactured by injection molding and 3D filament extrusion, and the rheological, electrical, and mechanical properties were analyzed and compared with those of virgin composites under the same conditions. Experimental results demonstrate that the recycled LDPE/MWCNT composites have similar rheological, electrical, and mechanical properties to virgin composites, if not better. Therefore, the recycled LDPE/MWCNT composites have a great potential for being used in engineering applications, while reducing the environmental impact.

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Higashi, Yuma, Tadashi Narabayashi, Yoichiro Shimazu, Masashi Tsuji, Syuichi Ohmori, Michitsugu Mori et Kenichi Tezuka. « Study on Pipe Wastage Mechanism by Liquid Droplet Impingement Erosion ». Dans 17th International Conference on Nuclear Engineering. ASMEDC, 2009. http://dx.doi.org/10.1115/icone17-76029.

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Evaluation of wastage speed for nuclear power plant maintains plant reliability and power up rating is important. There are two main cause of wastage flow accelerated corrosion (FAC) and mechanical erosion. This study is to develop evaluating the wastage speed by liquid droplet impingement erosion (LDIE). LDIE often occurs at downstream of corner of pipe or orifice. In this study, the liquid drop impinging tests were conducted with the test pieces mounted on a high speed rotating disk that cross thin water down jet and produced LDIE phenomena. The amount of the wastage by LDIE was evaluated by changing the rotational speed, the impingement frequency, and test piece materials. In addition, the generation mechanism of erosion was investigated by observing the surface of the test piece with a microscope. There is a method of evaluating by the mass difference before and after experiments. But this method is not correct because error becomes larger for mass measurement in the experiment, for the lost mass by LDIE is very little amount. Therefore, the method was developed to measure the volume in the erosion part. In this method, depth of LDIE was measured by the accuracy of ±0.01μm; therefore accurate measurement of the wastage can be improved.

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Rastimesina, Inna, Olga Postolachi, Valentina Josan, Alina Cotoman et Vera Mamaliga. « Screening of low density polyethylene degrading microorganisms ». Dans National Scientific Symposium With International Participation : Modern Biotechnologies – Solutions to the Challenges of the Contemporary World. Institute of Microbiology and Biotechnology, Republic of Moldova, 2021. http://dx.doi.org/10.52757/imb21.003.

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Bacteria, actinobacteria, and micromycetes stored in the National Collection of NonPathogenic Microorganisms (CNMN) were assessed for the capacity to grow and degrade LDPE. There were tested 15 strains of bacteria from genera Pseudomonas, Bacillus, Streptomyces, and Rhodococcus, and 15 strains of micromycetes from genera Penicillium and Aspergillus. Among the studied bacterial strains, actinobacteria were more effective in LDPE degradation than bacilli and Pseudomonas spp. The members of genus Penicillium, in comparing with Aspergillus spp., degraded LDPE more actively.

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Fetecau, Catalin, Felicia Stan, Petru Timotin, Nicoleta V. Stanciu et Razvan T. Rosculet. « Mechanical Behavior of LDPE/MWCNT Composites After Fatigue and Cryogenic Treatment ». Dans ASME 2018 13th International Manufacturing Science and Engineering Conference. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/msec2018-6532.

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In this study, the effects of fatigue and cryogenic treatments on the mechanical behavior of low-density polyethylene/ multi-walled carbon nanotube (LDPE/MWCNT) composites have been investigated. Injection-molded samples of LDPE/MWCNT composite with different MWCNT weight fractions (0.1–5.0 wt.%) were subjected to cryogenic and fatigue treatments under different testing conditions, and the residual-mechanical properties were investigated. To monitor the fatigue damage, additionally, the electrical conductivity was measured. The results show that the LDPE/MWCNT composites retained good residual-mechanical properties after fatigue (more than 85% of its initial Young modulus) and cryogenic (more than 75% of its initial tensile strength and Young’s modulus) treatment. For the LDPE/MWCNT composites, the electrically conductive nanotube network can be efficiently maintained up to 25 000 fatigue cycles.

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Rapports d'organisations sur le sujet "LdtE"

HEWITT AND ASSOCIATES INC ALBUQUERQUE NM. EM Visualization of Printed Circuit Board Assemblies. A Phase 1 SBIR on behalf of USAF ; SA-ALC/LDAE. Fort Belvoir, VA : Defense Technical Information Center, juin 1994. http://dx.doi.org/10.21236/ada293355.

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Li, Cheng, Xi Gao, Steven Rowan, Bryan Hughes, Jeremy Harris et William Rogers. Experimental investigation on the binary/ternary fluidization behavior of Geldart D type spherical LDPE, Geldart D type cylindrical wood and Geldart B type sand particles. Office of Scientific and Technical Information (OSTI), mars 2021. http://dx.doi.org/10.2172/1776642.

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