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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Can Space Time Encoding and Adaptive Equalization Benefit Rotary-Wing Missions at the Yuma Proving Ground?

Diehl, Michael, Swain, Jason, Wilcox, Tab 10 1900 (has links)
ITC/USA 2015 Conference Proceedings / The Fifty-First Annual International Telemetering Conference and Technical Exhibition / October 26-29, 2015 / Bally's Hotel & Convention Center, Las Vegas, NV / The US Army Yuma Proving Ground (YPG) utilizes telemetry in several critical ways. Data, video, and voice from test aircraft provides YPG the information necessary to effectively execute missions. This information must be displayed real-time for efficient use of available flight time, making a robust telemetry link vital. In seeking an increased telemetry downlink capability, YPG considered three new technologies: Space Time Coding (STC), Adaptive Equalization (EQ), and Low Density Parity Check (LDPC). These technologies have shown reduced multipath and increased datalink reliability on fixed-wing aircraft; however, YPG's concern was the technology's benefits on rotary wing aircraft tested here. To assess potential benefits of these technologies, YPG conducted flight tests using representative flight profiles and vendor-supplied equipment to collect quantitative and qualitative data.
32

The MED-PED project : presymptomatic diagnosis in families with disease- related LDL receptor gene mutations

Vergotine, Joseph Vincent 03 1900 (has links)
Thesis (MSc)--Stellenbosch University, 2000. / ENGLISH ABSTRACT: Familial hypercholesterolaemia (FH) contributes significantly to the high death rate from cardiovascular disease worldwide. FH is a common autosomal co-dominant disease characterised by raised cholesterol levels and premature coronary heart disease (CHD). Whilst these features usually are very prominent in homozygotes the clinical diagnosis of heterozygotes is complicated by variable phenotypic expression. Specific founder genes in the low-density lipoprotein receptor (LDLR) gene have increased the prevalence of FH in South African Afrikaners, Indians, Jews and Coloureds, and screening for these known mutations allows unequivocal diagnosis of FH-affected individuals. The systematic molecular analysis of FH resulted in the identification of at least ten founder-type LDLR gene mutations among the 56 different gene defects described to date in the diverse South African population. DNA screening of 792 at-risk family members for the FH-related mutations identified in 379 index cases, allowed accurate disease diagnosis in an additional 340 relatives and exclusion of the relevant mutation in 452 individuals. This effort forms part of the MED PED FH initiative, a collaborative project to "Make Early Diagnosis and Prevent Early Deaths in MEDical PEDigrees with FH". Evaluation of clinical criteria versus DNA diagnosis of three founder-related mutations (D154N, D206E and V408M) in the South African population demonstrated that the sensitivity and specificity of diagnoses, based on total cholesterol values measured in family members of index cases recruited for this study, were 88% and 77%, respectively. A population-directed DNA diagnosis of FH is therefore justified in South Africa on a routine basis, since expression of the defective gene measured in biochemical tests does not allow accurate diagnosis of FH in all cases. The application of mutation detection was illustrated by prenatal diagnosis of FH performed for a couple who are both heterozygous for the most common Afrikaner mutation, D206E. The mutation was absent in the foetus and a normocholesterolaemic infant was born. Prenatal diagnosis of FH, aimed at the detection of homozygous cases, is particularly applicable in populations and families with molecularly defined LDLR gene mutations. The MED-PED approach resulted in accurate diagnosis and subsequent treatment of FH in more patients, and referral to lipid clinics where they could receive the intensive care their condition justifies. Molecularly diagnosed FH patients will be the first to benefit from future treatment approaches based on mutation type. / AFRIKAANSE OPSOMMING: Familiële hiprcholesterolemie dra grootliks by tot die wêreldwye hoë sterftesyfer van kardiovaskulêre siekte. FH is 'n algemene outosomale ko-dominante siekte wat gekenmerk word deur verhoogde cholesterolvlakke en vroeë koronêre hartsiekte. Terwyl hierdie kenmerke prominent is in homosigote, word die kliniese diagnose van heterosigote bemoeilik deur variasie in fenotipiese uitdrukking. Spesifieke stigtergene in die lae-digtheids lipoproteien reseptor (LDLR) geen het die voorkomssyfer van FH verhoog in Suid Afrikaanse Afrikaners, Indiërs, Jode en Kleurlinge. Sifting vir hierdie bekende mutasies maak akkurate diagnose van FH geaffekteerde individue moontlik. Die sistematiese molekulêre analise van FH het aangetoon dat ten minste tien van die 56 verskillende geen defekte wat tot dusver beskryf is in die Suid-Afrikaanse populasie stigtertipe LDLR geen mutasies is. DNA sifting van 792 familielede vir die FH-verwante mutasie in 379 indeksgevalle geïdentifiseer is, het akkurate diagnose moontlik gemaak in 340 addisionele familielede, en uitsluiting daarvan in 452 individue. Hierdie poging vorm deel van die MED-PED FH ("Make Early Diagnosis and Prevent Early Deaths in MEDical PEDigrees with FH) inisiatief. Evaluering van kliniese kriteria teenoor DNA diagnose van drie stigter verwante mutasies (D154N, D206E en V408M) in die Suid Afrikaanse populasie het getoon dat die sensitiwiteit en spesifisiteit van die diagnose, wat gebasseer is op totale cholesterol waardes in familielede van indeksgevalle, onderskeidelik 88% en 77% was. 'n Populasie gerigte DNA diagnose van FH is dus geregverdig in Suid-Afrika op "n roetine basis, omdat die defektiewe geen nie altyd in biochemiese toetse uitgedruk word nie. Die waarde van mutasie opsporing is geillustreer deur 'n voorgeboortelike diagnose van FH wat aangevra is vir ouers wat beide heterosigoties is vir die mees algemene Afrikaner mutasie, D206E. Die mutasie was afwesig in die fetus en 'n normocholesterolemiese baba is gebore. Voorgeboortelike diagnose van FH, wat gemik is op die opsporing van homosigotiese gevalle, is veral van toepassing in populasies en families met bekende LDLR geen mutasies. Die MED-PED benadering het gelei tot akkurate diagnose en daaropvolgende behandeling van FH in meer pasiënte, en verwysings na lipiedklinieke waar hulle intensiewe aandag kan geniet. Molekulêre gediagnoseerde FH pasiënte sal die eerste wees om baat te vind by toekomstige behandeling wat moontlik gebasseer sal word op mutasie status.
33

Καταγραφή μεταλλάξεων του γονιδίου LDL-R σε ασθενείς οικογενούς υπερχοληστερολαιμίας

Κοχλιάδη, Ιωάννα 26 July 2013 (has links)
Οικογενής Υπερχοληστερολαιμία (FH) είναι η επικρατής αυτοσωμική νόσος, κατά την οποία τα επίπεδα χοληστερόλης στο αίμα είναι αυξημένα, εμφανίζονται ξανθώματα και ένα αυτοσωμικό επικρατές χαρακτηριστικό για στεφανιαία αρτηριακή νόσος (CAD). Η FH προκαλείται από ανωμαλία στο γονίδιο LDL-R και κάποιες φορές και στο γονίδιο APOB (apolipoprotein B-100). Η ετεροζυγία του LDLR συναντάται σε αναλογία πληθυσμού 1:500. Πρόσφατα παρατηρήθηκε ότι και το γονίδιο PCSK9 (proprotein convertase subtilisin/kexin type 9) προκαλεί FH. Τα γονίδια APOB και PCSK9 αποκλείστηκαν από τη συγκεκριμένη έρευνα. Στόχοι της διατριβής ήταν (α) η καταγραφή των μεταλλάξεων του γονιδίου LDLR (Low Density Lipoprotein Receptor) σε 21 πληθυσμούς, (β) ο υπολογισμός της συχνότητας αυτών των μεταλλάξεων και (γ) η προσθήκη αυτών των δεδομένων σε μία γενετική βάση δεδομένων, την FINDbase, η οποία δίνει πληροφορίες για τη συχνότητα μιας μετάλλαξης σε κάθε χώρα καθώς και το φαρμακευτικό δείκτη της. Από τους 21 πληθυσμούς, οι 14 προέρχονταν από Ευρωπαϊκές χώρες (Ελλάδα, Γερμανία,Πορτογαλία, Τσεχία, Ολλανδία, Ισπανία, Βρετανία, Ιταλία, Πολωνία, Σουηδία, Γαλλία, Αυστρία, Βέλγιο και Δανία) και οι υπόλοιποι από την Κίνα, την Ιαπωνία, την Μαλαισία, το Λίβανο, τις Φιλιππίνες, την Ταϊβάν και το Καναδά. Τα δεδομένα των μεταλλάξεων σε κάθε πληθυσμό αντλήθηκαν από άρθρα (papers) μέσω της Βάσης Δεδομένων Pubmed και της μηχανής αναζήτησης Google. Τα άρθρα επιλέχθηκαν με βάση (1) το μέγεθος του δείγματος και (2) τη χρονολογία πραγματοποίησης της έρευνας στο συγκεκριμένο πληθυσμό. Η συχνότητα υπολογίστηκε σε σύνολο χρωμοσωμάτων, δηλαδή στο διπλάσιο του μεγέθους του δείγματος. Ως ιδανικό μέγεθος δείγματος θεωρήθηκε ένα σύνολο τουλάχιστον 100 χρωμοσωμάτων, δηλ. 50 άτομα. Η καταγραφή των δεδομένων έγινε σε λογιστικό φύλλο Excel. Τα αποτελέσματα έδειξαν ότι υπάρχει μεγάλη ανομοιογένεια σε επίπεδο μεταλλάξεων ανάμεσα στους 21 πληθυσμούς. / Familial hypercholesterolaemia (FH), defined as the heritable occurence of severe hypercholesterolaemia with cholesterol deposits in tendons and premature heart disease, is caused by at least four genes in sterol and lipoprotein pathways and displays varying gene-dose effects. The genes are the low-density lipoprotein (LDL) receptor, apolipoprotein (apo) B, proprotein convertase subtilisin/kexin 9, and the autosomal recessive hypercholesterolaemia (ARH) adaptor protein. The world-wide prevalence of FH is about 1 in 500 people. In this assessment, the genes apoB, PCSK9 and ARH have been excluded. The aim of this study was the recording of LDLR mutations in 21 populations, the calculation of the mutations’ frequencies in each population and the introduction of these data in the National Ethnic Mutation DataBase (NEΜDB), FINDbase, which gives information about a mutation’s frequency in each country and also about its pharmacogenomic marker. Among 21 populations, 14 were of European origin (Greece, Germany, Portugal, Czech Republic, Netherlands, Spain, Great Britain, Italy, Poland, Sweden, France, Austria, Belgium and Denmark) and the remainders from China, Japan, Malaysia, Lebanon, Philippines, Taiwan and Canada. The mutation data in each population were derived from papers through the database of references, PubMed and the search engine, Google. The selection of papers was based on (1) the size of patient group and (2) the date of paper publication. The calculation of mutation frequency was based on the total number of chromosomes, which was the double size of the patient group. An ideal size of sample was at least 100 chromosomes, which means 50 index patients. The data were inserted in an excel file. The results showed that there is a great ανομοιογένεια in mutation level among 21 populations.
34

7,8-Dihydroneopterin-mediated protection of low density lipoprotein, but not human macrophages, from oxidative stress

Firth, Carole Anne January 2006 (has links)
Any lipoproteins and cells present in the inflammatory environment of atherosclerotic plaques are likely to be exposed to high levels of oxidative stress. As 7,8-dihydroneopterin (7,8-NP) is synthesized by interferon-γ (IFN-γ)-activated macrophages, this pteridine is also thought to exist at sites of inflammation. 7,8-NP s in vivo role remains controversial, but numerous in vitro studies have identified a radical scavenging activity. The possibility of 7,8-NP protecting against oxidative damage in inflammatory environments like plaque was investigated in this thesis. Both human monocyte-derived macrophages (HMDMs) and low density lipoprotein (LDL) were used as substrates. The extent of protein hydroperoxide formation in each model, and 7,8-NP s effect on this process, were specifically studied since most previous research has focussed on lipid rather than protein peroxidation. For the first time, neopterin (including oxidized 7,8-NP) was also directly detected by high performance liquid chromatography in the inflammatory environments of 19 pus and two atherosclerotic plaque samples. Peak concentrations even reached the low micromolar range. The positive correlation identified in the pus between neopterin and a well known antioxidant, vitamin E, further hinted at a potential antioxidant function. However, no significant association was noted between neopterin and markers of protein or lipid oxidation. Exposure of HMDMs to the AAPH peroxyl radical generator resulted in significant quantities of lipid hydroperoxides but not protein hydroperoxides, as detected by the FOX assays. This is likely due to the large accumulation of polyunsaturated fatty acidrich lipid in the primary HMDMs during differentiation in 10% human serum and is of relevance to atherosclerotic plaque, where macrophages also become lipid-loaded. The addition of up to 200μM 7,8-NP failed to prevent AAPH-induced lipid peroxidation and was also unable to inhibit a loss of cellular thiols or viability. This lack of effect suggests the damaging peroxyl radicals are not being scavenged by 7,8-NP. The high lipid content of HMDM cells appears to cause the AAPH and/or 7,8-NP to localize to a cellular site, where they are unable to interact. Macrophage-mediated oxidation of LDL in iron(II)-supplemented Hams F10 was associated with the formation of 30-40 moles of protein hydroperoxides per mole of LDL. The close parallel between protein and lipid peroxidation supports the theory that lipid-derived radicals are involved in protein hydroperoxide formation on LDL and indicates that protein hydroperoxides are an early product of LDL oxidation. Their detection during exposure of LDL to both the THP-1 macrophage cell line and primary HMDM cells confirms that protein hydroperoxides are also a normal consequence of macrophage-mediated LDL oxidation. Incubation of LDL with micromolar 7,8-NP prevented macrophage-mediated protein hydroperoxide formation in a concentration-dependent manner. Lipid oxidation and vitamin E loss were similarly inhibited by 7,8-NP during the cell-mediated attack of LDL. Kinetic analysis revealed protection due to extension of the lag phase, with 7,8-NP depletion and initiation of the propagation phase coinciding. This supports a radical scavenging activity for 7,8-NP, resulting in protection of the entire LDL particle. By contrast, the release of nanomolar quantities of 7,8-NP by IFN-γ-stimulated THP-1 macrophages failed to prevent LDL oxidation. HMDMs activated by IFN-γ did significantly inhibit LDL oxidation, including protein hydroperoxide formation, for up to 48 hours but this antioxidant effect was not due to the de novo synthesis of 7,8-NP. These results indicate that both the prevalence of protein hydroperoxides, and the ability of 7,8-NP to act as an antioxidant, depend on the system under investigation. Neopterin exists in inflammatory environments but, considering the lack of protection against AAPH-mediated HMDM oxidation and the 7,8-NP concentration required to inhibit macrophage-mediated LDL oxidation, strong evidence for an antioxidant activity of 7,8-NP in atherosclerotic plaque is currently lacking.
35

Study of Numerical Model Parameters and Crack Tip of a Packaging Materials

Kodavati, Venkata Seshank, Buraga, Devi Prasad January 2017 (has links)
Packaging industries widely use Low-Density Polyethylene (LDPE) in manufacturing different types of containers to store the food products. They are difficult to model numerically in order to have similar experimental response. This research deals with the study of numerical material model parameters of continuum LDPE. It is carried out with the help of experiments along with the numerical simulation of LDPE. Study of stress-strain distribution at crack tip and elements close to the tip is carried out in the LDPE material with the pre-existing center crack with varying lengths. By implementing an optimization algorithm and automating the simulation with the help of python code, we obtain a set of parameters. This obtained data for the material can be used directly for numerical simulation in the future without carrying out additional experimental studies. After implementing the optimization algorithm is also validated, against the results that were close to the experimental response.
36

Efeito da imunização passiva com fragmentos variáveis de cadeia única anti-LDL eletronegativa na aterosclerose experimental / Passive immunization effect with anti-electronegative LDL single chain fragments variable in experimental atherosclerosis

Cavalcante, Marcela Frota 04 October 2012 (has links)
A aterosclerose é uma doença crônico-inflamatória multifatorial com o envolvimento do sistema imunológico, sendo o resultado da interação de diferentes elementos celulares. A lipoproteína de baixa densidade eletronegativa [LDL(-)], capaz de induzir o acúmulo de ésteres de colesterol em macrófagos e a subsequente formação de células espumosas, desempenha um papel-chave na doença. Anticorpos recombinantes têm sido gerados nas últimas décadas, como o scFv (single chain fragment variable), com o intuito de serem utilizados como uma novas alternativas de prevenção para o surgimento da lesão. Diante do papel da LDL(-) na aterosclerose, este projeto avaliou o efeito da imunização passiva de camundongos LDLr-/-- com scFv anti-LDL(-) em solução e scFv anti-LDL(-) conjugado a nanocápsulas, em relação ao desenvolvimento e progressão da aterosclerose. Após obtenção do scFv e sua conjugação à nanocápsulas (NC-scFv), ensaios in vitro determinaram a diminuição da captação de LDL(-) em macrófagos tratados com o scFv 2C7 anti-LDL(-) em solução. No entanto, o tratamento com NC-scFv promoveu o aumento da internalização de LDL(-) em relação ao controle, possivelmente por um mecanismo de endocitose mediada por receptor específico. Estudos in vivo determinaram que camundongos LDLr-/- com idade entre 2 e 3 meses tratados com o scFv em solução apresentaram menor área de lesão aterosclerótica (p<0,05) quando comparados ao controle e que animais com 3 a 4 meses de idade tratados com NC-scFv demonstraram uma tendência à diminuição do mesmo parâmetro. Na análise da expressão de proteínas por imunohistoquímica, ambos os grupos tratados com scFv 2C7 anti-LDL(-) em solução e NC-scFv demostraram redução significativa da expressão dos receptores CD14 e TLR-4 no local da lesão. Esse achado tem grande importância, uma vez que dados da literatura apresentam ambos os receptores como possíveis candidatos ao reconhecimento da LDL(-). Diante dos dados obtidos, o estudo evidenciou a eficácia do scFv 2C7 anti-LDL(-) em solução e da formulação NC-scFv no contexto da aterosclerose, possibilitando a sua utilização como estratégias terapêuticas na intervenção precoce para prevenir o desenvolvimento e a progressão da doença. / Atherosclerosis is a chronic inflammatory multifactorial disease related to the immune system and being the result of interaction of different cellular elements. The electronegative LDL, since the changes undergone by this particle are able to induce the accumulation of cholesterol esters in macrophages and the subsequent formation of foam cells, plays a key role in atherosclerosis. Recombinant antibodies have been generated in recent decades, such as scFv, (single chain fragment variable), and they may be used as a new alternative treatment for atherosclerosis treatment or prevention. Considering the role of LDL(-) in atherosclerosis, this project evaluated the effects of the treatment with anti-LDL(-) scFv 2C7 solution and anti-LDL(-) scFv conjugated to nanocapsules as a passive immunization strategy on atherosclerosis induced in LDL receptor knockout mice. After obtaining the anti-LDL(-) scFv 2C7 solution and its conjugation to nanocapsules (NC-scFv), in vitro tests led to the decrease in LDL(-) uptake in macrophages treated with anti-LDL(-) scFv 2C7. However, the treatment of macrophages with NC-scFv promoted increased internalization of LDL(-) as compared to control, possibly due to a mechanism of specific receptor-mediated endocytosis. In vivo studies have determined that LDLR-/- mice aged 2 and 3 months treated with anti-LDL(-) scFv 2C7 solution showed less atherosclerotic lesion area (p <0.05) compared to control and animals aged 3 to 4 months treated with NC-scFv showed a decreasing tendency of the same parameter. In the analysis of protein expression by immunohistochemistry, both groups treated with anti-LDL(-) scFv 2C7 solution and NC-scFv showed significant reduction of CD14 receptor expression and TLR-4 at the lesion site. This finding is of great importance, since the literature has both receptors as candidates for recognition of the LDL(-). From the data obtained, the study demonstrated the efficacy of treatments anti-LDL(-) scFv 2C7 in solution and NC-scFv in the context of atherosclerosis, enabling their use as therapeutic strategies in the early intervention to prevent the development and progression of the disease.
37

cDNA cloning and transcriptional regulation of the vitellogenin receptor from the imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae)

Chen, Mei-Er 17 February 2005 (has links)
Receptors that transport vitellogenin into oocytes are of vital importance to egg-laying species because they promote oocyte development. In this study, we describe the cloning of the first hymenopteran vitellogenin receptor (VgR) cDNA. Using reverse transcription polymerase chain reaction (RT-PCR) and both 5’- and 3’- rapid amplification of cDNA ends (RACE), cDNA fragments encompassing the entire coding region of a putative VgR from fire ant (= SiVgR) were cloned and sequenced. The complete SiVgR cDNA has a length of 5764 bp encoding a 1782-residue protein with a predicted molecular mass of 201.3 kDa. The deduced amino acid sequence of the SiVgR revealed that it encoded a protein belonging to the low-density lipoprotein receptor superfamily. The number and arrangement of modular domains of SiVgR are the same as those of mosquito and fruit fly VgRs, except there are only four Class A cysteine-rich repeats in the first ligand binding domain of SiVgR compared to five in the mosquito and fruit fly. The deduced amino acid sequence of the SiVgR exhibited 35% and 31% identity to those of the mosquito and fruit fly VgRs, respectively. Northern blot analysis demonstrated that the 7.4-kb SiVgR mRNA was present only in Northern blot analysis demonstrated that the 7.4-kb SiVgR mRNA was present only in ovaries of reproductive females − both alates (virgins) and queens (mated) and was more abundant in alates. The developmental profile of transcriptional expression was determined by semiquantitative RT-PCR. It showed that the SiVgR transcript increased 6-fold from 0- to 10-days after mating, then remained constant through 30 days. It also showed that the SiVgR transcripts increased with age in alate virgin females. The transcriptional expression of the SiVgR was up-regulated more than two-fold by methoprene, a juvenile hormone analog, as determined by using an in vitro system. This suggested the SiVgR gene is JH regulated.
38

PSPの低圧力域における基礎特性に関する研究

新美, 智秀, NIIMI, Tomohide, 吉田, 昌記, YOSHIDA, Masaki, 近藤, 誠, KONDO, Makoto, 大島, 佑介, OSHIMA, Yusuke, 森, 英男, MORI, Hideo, 江上, 泰広, EGAMI, Yasuhiro, 浅井, 圭介, ASAI, Keisuke, 西出, 宏之, NISHIDE, Hiroyuki 12 1900 (has links)
No description available.
39

In-line Extrusion Monitoring and Product Quality

Farahani Alavi, Forouzandeh 15 September 2011 (has links)
Defects in polyethylene film are often caused by contaminant particles in the polymer melt. In this research, particle properties obtainable from in-line melt monitoring, combined with processing information, are used to predict film defect properties. “Model” particles (solid and hollow glass microspheres, aluminum powder, ceramic microspheres, glass fibers, wood particles, and cross-linked polyethylene) were injected into low-density polyethylene extruder feed. Defects resulted when the polyethylene containing particles was extruded through a film die and stretched by a take-up roller as it cooled to form films 57 to 241mm in thickness. Two off-line analysis methods were further developed and applied to the defects: polarized light imaging and interferometric imaging. Polarized light showed residual stresses in the film caused by the particle as well as properties of the embedded particle. Interferometry enabled measures of the film distortion, notably defect volume. From the images, only three attributes were required for mathematical modeling: particle area, defect area, and defect volume. These attributes yielded two ”primary defect properties”: average defect height and magnification (of particle area). For all spherical particles, empirical correlations of these properties were obtained for each of the two major types of defects that emerged: high average height and low average height defects. Analysis of data for non-spherical particles was limited to showing how, in some cases, their data differed from the spherical particle correlations. To help explain empirical correlations of the primary defect properties with film thickness, a simple model was proposed and found to be supported by the high average height defect data: the “constant defect volume per unit particle area” model. It assumes that the product of average defect height and magnification is a constant for all film thicknesses. A numerical example illustrates how the methodology developed in this work can be used as a starting point for predicting film defect properties in industrial systems. A limitation is that each prediction yields two pairs of primary defect property values, one pair for each defect type. If it is necessary to identify the dominant type, then measurement of a length dimension of sufficient defects in the film is required.
40

In-line Extrusion Monitoring and Product Quality

Farahani Alavi, Forouzandeh 15 September 2011 (has links)
Defects in polyethylene film are often caused by contaminant particles in the polymer melt. In this research, particle properties obtainable from in-line melt monitoring, combined with processing information, are used to predict film defect properties. “Model” particles (solid and hollow glass microspheres, aluminum powder, ceramic microspheres, glass fibers, wood particles, and cross-linked polyethylene) were injected into low-density polyethylene extruder feed. Defects resulted when the polyethylene containing particles was extruded through a film die and stretched by a take-up roller as it cooled to form films 57 to 241mm in thickness. Two off-line analysis methods were further developed and applied to the defects: polarized light imaging and interferometric imaging. Polarized light showed residual stresses in the film caused by the particle as well as properties of the embedded particle. Interferometry enabled measures of the film distortion, notably defect volume. From the images, only three attributes were required for mathematical modeling: particle area, defect area, and defect volume. These attributes yielded two ”primary defect properties”: average defect height and magnification (of particle area). For all spherical particles, empirical correlations of these properties were obtained for each of the two major types of defects that emerged: high average height and low average height defects. Analysis of data for non-spherical particles was limited to showing how, in some cases, their data differed from the spherical particle correlations. To help explain empirical correlations of the primary defect properties with film thickness, a simple model was proposed and found to be supported by the high average height defect data: the “constant defect volume per unit particle area” model. It assumes that the product of average defect height and magnification is a constant for all film thicknesses. A numerical example illustrates how the methodology developed in this work can be used as a starting point for predicting film defect properties in industrial systems. A limitation is that each prediction yields two pairs of primary defect property values, one pair for each defect type. If it is necessary to identify the dominant type, then measurement of a length dimension of sufficient defects in the film is required.

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