scholarly journals Effects of long-term deep freezing on human femoral cartilage: differential scanning calorimetric (DSC) analysis and histopathological evaluations

2021 ◽  
Author(s):  
Ivett Szabó ◽  
Balázs Patzai ◽  
Dénes Lőrinczy
Keyword(s):  
Detailed Analysis ◽  
Storage Time ◽  
Morphological Changes ◽  
Qualitative Evaluation ◽  
Cartilage Destruction ◽  
Differential Scanning Calorimetric ◽  
Scanning Calorimetry ◽  
Human Cartilage ◽  
Deep Freezing ◽  
Long Time

AbstractResults from our previous study proved that differential scanning calorimetry (DSC) is a reliable method for qualitative evaluation of morphological changes in human cartilage samples caused by cryopreservation and storage time correlates with graft quality [1, 2]. Our current aim was to specify/characterise the effects of deep-freezing on hyaline cartilage in conjunction with length of storage time. Detailed analysis included DSC and histological measurements which showed distinctive differences. Based on our histological examinations, we could not confirm significant association between cartilage destruction and long-time storage, but the DSC results exhibited a definite change in thermal parameters after the 6th week cryopreservation. A modified and more detailed analysis would be useful to determine the effects of deep-freezing.

scholarly journals Laboratory Study of the Ultraviolet Radiation Effect on an HDPE Geomembrane

Membranes ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 390
Author(s):  
Fernando Luiz Lavoie ◽  
Marcelo Kobelnik ◽  
Clever Aparecido Valentin ◽  
Érica Fernanda da Silva Tirelli ◽  
Maria de Lurdes Lopes ◽  
...  
Keyword(s):  
Ultraviolet Radiation ◽  
Morphological Changes ◽  
Field Performance ◽  
Melt Flow Index ◽  
Flow Index ◽  
Test Results ◽  
Upward Trend ◽  
Scanning Calorimetry ◽  
Ultraviolet Exposure ◽  
Brittle Behavior

High-density polyethylene (HDPE) geomembranes are polymeric geosynthetic materials usually applied as a liner in environmental facilities due to their good mechanical properties, good welding conditions, and excellent chemical resistance. A geomembrane’s field performance is affected by different conditions and exposures, including ultraviolet radiation, thermal and oxidative exposure, and chemical contact. This article presents an experimental study with a 1.0 mm-thick HDPE virgin geomembrane exposed by the Xenon arc weatherometer for 2160 h and the ultraviolet fluorescent weatherometer for 8760 h to understand the geomembrane’s behavior under ultraviolet exposure. The evaluation was performed using the melt flow index (MFI) test, oxidative-induction time (OIT) tests, tensile test, differential scanning calorimetry (DSC) analysis, and Fourier transform infrared spectroscopy (FTIR) analysis. The sample exposed in the Xenon arc equipment showed a tendency to increase the MFI values during the exposure time. This upward trend may indicate morphological changes in the polymer. The tensile behavior analysis showed a tendency of the sample to lose ductility, without showing brittle behavior. The samples’ OIT test results under both device exposures showed faster antioxidant depletion for the standard OIT test than the high-pressure OIT test. The DSC and FTIR analyses did not demonstrate the polymer’s changes.

Morphological basis for the complex melting behaviour of isotactic polystyrene

e-Polymers ◽  
2002 ◽  
Vol 2 (1) ◽  
Author(s):  
Mahmoud Al-Hussein ◽  
Gert Strobl
Keyword(s):  
Morphological Changes ◽  
Melting Behaviour ◽  
Temperature Dependent ◽  
Molten Material ◽  
Scanning Calorimetry ◽  
Isotactic Polystyrene ◽  
X Ray ◽  
Long Period ◽  
X Ray Scattering ◽  
Increasing Temperature

AbstractTemperature-dependent small-angle X-ray scattering spectroscopy of isothermally cold crystallized isotactic polystyrene revealed considerable morphological reorganization during subsequent heating to the melt. Both the crystalline thickness and the long period increased continuously with increasing temperature before the samples finally melted. The temperature dependence of these changes correlated very well with the melting behaviour observed with differential scanning calorimetry. As the temperature increased during a heating scan, the initial lamellae that formed during isothermal crystallization showed only little reorganization until they started to melt. Then, the molten material recrystallized continuously into increasingly thicker lamellae at increasing temperature until they finally melted. As the crystallization temperature approached the final melting temperature of the recrystallized lamellae, the initial lamellae melted without further recrystallization and no morphological changes were seen in this case.

scholarly journals MODERN CONCEPTION AS TO THE FUNCTIONAL MORPHOLOGY OF THE OLFACTORY SYSTEM AND ITS CHANGES UNDER THE INFLUENCE OF SOME EXOGENOUS POLLUTANTS

2019 ◽  
Vol 23 (3-4) ◽  
pp. 37-40
Author(s):  
A.D. Shkodina ◽  
R.M. Hrinko ◽  
I.I. Starchenko
Keyword(s):  
Environmental Factors ◽  
Olfactory Epithelium ◽  
Functional Organization ◽  
Morphological Changes ◽  
Human Life ◽  
Experimental Studies ◽  
Experimental Models ◽  
Functional Changes ◽  
Olfactory Analyzer ◽  
Long Time

The interaction between a body and an environment provides the main aspects of human life. The study of the functional structure of the olfactory analyzer plays an important role both in clinical and in experimental studies, but the question of its features in humans needs detailed research. The paper presents the modern data of the structural and functional organization of the olfactory analyzer. Particular attention is paid to the structural organization of olfactory bulbs as most complicated and least studied component of the olfactory analyzer. The morphological and functional changes of the olfactory analyzer are developing in some diseases and in action of adverse environmental factors are described while the accentuation is placed on the differences of the mechanism in the pathogenesis of damage to the olfactory analyzer, depending on the nature of the influence of pathogenic factors. In this way as the result of short-term intense effects of the pollutant, irreversible atrophic changes are primarily affected to the olfactory epithelium, thus, to some extent, preventing the spread of the toxin to other analyzer structures. Conversely, a long-term exposure to low doses usually retains the functional activity of the olfactory epithelium, while harmful substances penetrate the central unit of the olfactory analyzer. In such cases, the olfactory dysfunction can be diagnosed after a long time after the start of the cohort with certain pollutants. Currently, studies of the influence of exogenous toxins on various parts of the olfactory analyzer on animal experimental models are quite active. At the same time, the issue of functional and morphological changes in various structural components of the human olfactory analyzer under the influence of negative environmental factors remains poorly understood and requires further morphological and biochemical studies, in order to be able to further develop effective therapeutic and prophylactic means.

scholarly journals Statistical Analysis of the Results of Test Artillery Tracers

2020 ◽  
Vol 11 (4) ◽  
pp. 9-26
Author(s):  
Dariusz AMPUŁA
Keyword(s):  
Statistical Analysis ◽  
Storage Time ◽  
Test Methodology ◽  
Diagnostic Decision ◽  
Laboratory Test Results ◽  
Long Time ◽  
Evaluation Module ◽  
The Impact ◽  
Shooting Decisions

A statistical analysis of multiyear laboratory test results of artillery tracers number 8 is presented in this article. This analysis was aimed at testing the impact of a natural ageing process on quality indicators during the long-time storage of these tracers. The influence of storage time on taking a diagnostic decision, relating to quality of lots after the conducted laboratory tests and on different classes of inconsistencies that occurred during these tests, was analysed. A detailed analysis of the impact of the storage time on diagnostic shooting decisions taken was also presented. The conducted statistical analysis suggests an assumption, that it is possible to change an evaluation module in the previous test’s methodology. Modification of this evaluation module will not negatively impact on the quality of further diagnostic tests. It will not negatively impact on correct evaluation of the prediction process of the tested elements of ammunition such as artillery tracers. The statistical analysis, carried out in the article, may have a significant impact on the modification of test methodology of the artillery tracers.

Tuning the Mechanical Properties of High-Density Polyethylene by ECAE Process

2015 ◽  
Author(s):  
Catalin Fetecau ◽  
Felicia Stan ◽  
Laurentiu Sandu ◽  
Florin Susac
Keyword(s):  
Mechanical Properties ◽  
High Density Polyethylene ◽  
Equal Channel Angular Extrusion ◽  
Morphological Changes ◽  
Longitudinal Axis ◽  
High Density ◽  
Scanning Calorimetry ◽  
Plastic Deformations ◽  
The Third ◽  
Indentation Tests

This paper investigates the ability of the equal channel angular extrusion (ECAE) process to induce morphological changes and hence tune the mechanical properties of high-density polyethylene (HDPE). In this study, differential scanning calorimetry (DSC), compression and cylindrical macro-indentation tests have been used to investigate the evolution of the mechanical properties of HDPE processed by ECAE up to four passes via route BC, i.e. counter clockwise 90° billet rotation about its longitudinal axis. It was found that the ECAE process induces significant plastic deformations with changes in the crystalline structure. The ECAE process increased the HDPE crystallinity by 10 to 15%. The number of ECAE passes has a significant effect on the magnitude of the mechanical properties especially on the elastic modulus and yield stress. Young’s modulus and yield strength decreased with increasing the number of ECAE passes and reached a stationary state after the third pass.

Differential Scanning Calorimetric Analysis for Incompatibility: Sodium Stearate/Magnesium Stearate and Acidic Compounds

2020 ◽  
Vol 859 ◽  
pp. 307-312
Author(s):  
Pornsit Chaiya ◽  
Thawatchai Phaechamud
Keyword(s):  
Sodium Stearate ◽  
Pharmaceutical Formulations ◽  
Pharmaceutical Compounds ◽  
Magnesium Stearate ◽  
Differential Scanning Calorimetric ◽  
Salt Form ◽  
Scanning Calorimetry ◽  
Calorimetric Analysis ◽  
Pharmaceutical Excipient ◽  
Acidic Compounds

Compatibility investigation was performed between stearate lubricants (sodium stearate and magnesium stearate) and acidic pharmaceutical compounds (ibuprofen, indomethacin and valproic acid) and citric acid as acidic pharmaceutical excipient using differential scanning calorimetry (DSC). Alteration in DSC thermogram was found in all mixtures. There was a presence of melting endothermic peak of stearic acid in all mixtures (except that of stearate lubricants and indomethacin) indicating breakage of salt form of stearate lubricants depended on the physicochemical properties of drug compounds and pharmaceutical excipient. Therefore, the avoidance for using stearate lubricants with acidic pharmaceutical compounds and excipient should be concerned in development of pharmaceutical formulations.

scholarly journals Crisis in Boeing 787 Dreamliner: An Investigation from Project Management Control Perspective

2018 ◽  
Vol 8 (4) ◽  
pp. 242
Author(s):  
Suchandra Paul
Keyword(s):  
Project Management ◽  
Detailed Analysis ◽  
Management Control ◽  
The Other ◽  
Management Process ◽  
Final Phase ◽  
Entire Process ◽  
Innovative Solutions ◽  
Long Time

The organizational project management control has been the area of great interest from long time among the investigators who validated that there is a great necessity of control approaches in an organization to acquire their goals. In this paper, a detailed analysis describing the stages associated with control in project management process has been illustrated. In the first phase the proposed plans are outlined with a follow up on the deviation of the plans with causes. In the final phase a detailed solution analysis was carried on what the company did to fix the series of delays along with some suggestions stating proper ways of dealing the situations. This research gives a wide overview on the problems that 787 Dreamliner faced during its manufacturing and delivery process. The analysis was done on the control perspective. Innovative solutions was laid down which if applied during the service procedures could have avoided the problems related to delay of 787 Dreamliner’s delivery. The main intention of this research is that the solutions and strategies provided can be implemented successfully to the other organization for better planning and handling of entire process ultimately minimizing the downtime and increasing the productivity of the organization.

scholarly journals Comparative analysis of crystallization behavior induced by different mineral fillers in polypropylene nanocomposites

2020 ◽  
Vol 10 ◽  
pp. 184798042092275
Author(s):  
Luciana A. Castillo ◽  
Silvia E. Barbosa
Keyword(s):  
Thermal Properties ◽  
Comparative Analysis ◽  
Crystallization Behavior ◽  
Morphological Changes ◽  
Filler Concentration ◽  
Mineral Particle ◽  
Scanning Calorimetry ◽  
Crystalline Phases ◽  
Polypropylene Nanocomposites ◽  
Mineral Fillers

A comparative analysis of crystallization behavior induced by several mineral fillers in polypropylene nanocomposites was performed. Morphological changes and thermal properties of nanocomposites were evaluated, considering the influence of shape, crystalline morphology, and concentration of mineral particles. For this study, hydrated magnesium silicates with different particle morphologies, such as platelets (talc) and fibers (sepiolite), were used for nanocomposites. In addition, to analyze the effect of mineral crystallinity on nanocomposites, talc and sepiolite from different origin and genesis were selected. Nanocomposites were compounded and injection molded, using different filler concentration (0, 1, and 3% w/w) for each mineral particle. To evaluate the particle influence on nanocomposite crystallinity, X-ray diffraction was used to determine crystalline phases and crystal orientation, meanwhile differential scanning calorimetry was performed to obtain thermal properties. Main results revealed that talc has a higher nucleating effect on polypropylene matrix than sepiolite fibers, regardless of their origin and genesis. Meanwhile, a transcrystalline layer that surrounds the fiber surface is observed for nanocomposite containing sepiolite. Moreover, Argentinean talc induces different crystalline phases in nanocomposite with respect to Australian one, which partly influences on mechanical properties.

Two New Thermotropic Liquid Crystalline Polyesters and their Composites: Synthesis and Characterization

2009 ◽  
Vol 87-88 ◽  
pp. 154-159
Author(s):  
Chuan Ji Zhang ◽  
Zhi Xiong Huang ◽  
Min Xian Shi ◽  
Ming Zhang
Keyword(s):  
Mechanical Properties ◽  
Liquid Crystalline ◽  
Synthesis Process ◽  
Differential Scanning Calorimetric ◽  
Melting Points ◽  
Texture Characteristic ◽  
Scanning Calorimetry ◽  
Heating And Cooling ◽  
Melt Polycondensation ◽  
Monomer Structure

Two new series of liquid crystalline polyesters were synthesized using melt polycondensation reaction.Glass fiber,as a reinforcement,was meltpolymerized with 4-acetoxybenzoic(ABA),4,4＇-diacetoxybiphenyl, isophthalic acid(IA) and terephthalic acid(TA) to make TLCP/GF composites with a good mechanical properties.All the obtained compounds were characterized by conventional spectroscopic methods. The structure of the target compounds and intermediates was conformed by the IR, 1H NMR and SEM. The thermal behavior of the polymers has been characterized using polarized optical microscopy and differential scanning calorimetry. The effect of monomer structure and mechanical properties has been investigated on the prepared polyesters. These compounds show a high birefringent Schlierene texture characteristic of the nematic phase on heating and cooling experiments. This was further confirmed using differential scanning calorimetric investigations.The melting points of polymers having a central 4,4’-biphenyldicarboxylate residue have broad endotherms. The glass transition temperature values of polyesters are not effect by the glass fiber.According to the SEM result showed that the composite had strong fiber-matrix adhesion.The effect of copolymerization with added glass fiber in synthesis process is compared with that of the anlogous homopolyesters by other processing mode.Our finding shows that the copolymers exhibit reduced technical process and maintained mechanical properties.

Halogenated methacrylate-based aluminum oxide (Al2O3) nanocomposites

2015 ◽  
Vol 30 (6) ◽  
pp. 762-772
Author(s):  
Kathikar Abdul Wasi ◽  
Sakvai Mohammed Safiullah ◽  
Kottur Anver Basha
Keyword(s):  
Aluminum Oxide ◽  
Polymer Matrix ◽  
Glycidyl Methacrylate ◽  
Morphological Changes ◽  
Thermal Studies ◽  
Gel Permeation Chromatography ◽  
Decomposition Temperature ◽  
Scanning Calorimetry ◽  
Initial Decomposition Temperature ◽  
Mixing Techniques

The aim of the work is to prepare the halogenated methacrylate-based polymer nano-aluminum oxide (Al2O3) composites and to study the effect of incorporated nano-Al2O3 on morphological and thermal studies. A functional 2,4,6-tribromophenyl methacrylate- co-glycidyl methacrylate copolymer microspheres (poly(TBPMA- co-GMA); pTG) by emulsion solvent evaporation techniques, whereas (2,4,6-tribromophenyl methacrylate- co-glycidyl methacrylate)-Al2O3 nanocomposites (pTG-Al2O3 nanocomposites) were prepared by solution mixing techniques. The pTG and its Al2O3 nanocomposites were structurally characterized by Fourier transform infrared (FTIR) spectroscopy. Thermal studies of pTG and its Al2O3 nanocomposites were carried out by thermogravimetric analysis and differential scanning calorimetry . The molecular weight of the pTG was determined by gel permeation chromatography. The size distribution and morphology of the pTG and its Al2O3 nanocomposites were determined by scanning electron microscopy (SEM). The FTIR results reveal that there is no significant interaction between the polymer matrix and Al2O3 nanoparticle. The significant increase in the initial decomposition temperature and glass transition temperature of pTG-Al2O3 nanocomposites compared to its polymer was due to the incorporation of nano-Al2O3 in the polymer matrix. The SEM observation provides the information about the morphological changes that arise in polymer matrix due to the incorporation of nano-Al2O3.

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