| 1. |
- Jäverberg, Nadejda, 1977-, et al.
(författare)
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Dielectric Properties of Alumina-filled Poly (ethylene-co-butyl acrylate) Nanocomposites Part I - Dry Studies
- 2012
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Ingår i: IEEE transactions on dielectrics and electrical insulation. - 1070-9878 .- 1558-4135. ; 19:2, s. 383-390
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Tidskriftsartikel (refereegranskat)abstract
- The dielectric properties of poly (ethylene-co-butyl acrylate) with 13 wt% of butyl acrylate (EBA) filled with alumina nanoparticles were studied as a function of particle size, particle coating, filler content (2, 6 or 12wt%) and temperature. The particles were either unmodified or surface-treated with either aminopropyltriethoxy silane or octyltriethoxy silane. The complex permittivity was measured with frequencies varying between 1 mHz and up to 1 kHz at different temperatures (25, 45 and 65 degrees C). Measurements were performed in dry conditions. From the dielectric spectroscopy measurements it can be seen that the tan delta for the dry samples is almost independent of the type of the particle coating used. It does, however, depend on the particle size, filler content and temperature.
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| 2. |
- Jäverberg, Nadejda, 1977-, et al.
(författare)
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Dielectric Properties of Alumina-filled Poly (ethylene-co-butyl acrylate) Nanocomposites Part II - Wet Studies
- 2012
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Ingår i: IEEE transactions on dielectrics and electrical insulation. - 1070-9878 .- 1558-4135. ; 19:2, s. 391-399
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Tidskriftsartikel (refereegranskat)abstract
- The influence of moisture on the dielectric properties of different types of poly (ethylene-co-butyl acrylate) filled with alumina nanoparticles was systematically investigated by varying the type of aluminum oxide, particle surface treatment and filler content (2, 6 and 12 wt%). The nanoparticles were either unmodified or surface-treated with either aminopropyl triethoxysilane or octyltriethoxy silane. The complex permittivity was measured with an IDA200 dielectric spectroscopy analyzer at applied voltage of 200 V-peak with frequencies varying between 1 mHz and 1 kHz. The measurements were performed at 25 degrees C and relative air humidities of 24, 54 and 86 %. In order to expand the frequency range the HP 4284A precision LCR meter was used for measuring sample impedance at the frequency range of 100 Hz to 1 MHz. From the frequency dependence of dielectric losses it can be seen that absorbed water plays a significant role in determining the dielectric properties of the nanocomposites. The magnitude of tan delta seems to be determined primarily by the particle size and filler content, while the peak frequency is mostly influenced by the amount of absorbed water and the type of particle coating.
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| 3. |
- Lozano, Rafael, et al.
(författare)
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Measuring progress from 1990 to 2017 and projecting attainment to 2030 of the health-related Sustainable Development Goals for 195 countries and territories: a systematic analysis for the Global Burden of Disease Study 2017
- 2018
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Ingår i: The Lancet. - : Elsevier. - 1474-547X .- 0140-6736. ; 392:10159, s. 2091-2138
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Tidskriftsartikel (refereegranskat)abstract
- Background: Efforts to establish the 2015 baseline and monitor early implementation of the UN Sustainable Development Goals (SDGs) highlight both great potential for and threats to improving health by 2030. To fully deliver on the SDG aim of “leaving no one behind”, it is increasingly important to examine the health-related SDGs beyond national-level estimates. As part of the Global Burden of Diseases, Injuries, and Risk Factors Study 2017 (GBD 2017), we measured progress on 41 of 52 health-related SDG indicators and estimated the health-related SDG index for 195 countries and territories for the period 1990–2017, projected indicators to 2030, and analysed global attainment. Methods: We measured progress on 41 health-related SDG indicators from 1990 to 2017, an increase of four indicators since GBD 2016 (new indicators were health worker density, sexual violence by non-intimate partners, population census status, and prevalence of physical and sexual violence [reported separately]). We also improved the measurement of several previously reported indicators. We constructed national-level estimates and, for a subset of health-related SDGs, examined indicator-level differences by sex and Socio-demographic Index (SDI) quintile. We also did subnational assessments of performance for selected countries. To construct the health-related SDG index, we transformed the value for each indicator on a scale of 0–100, with 0 as the 2·5th percentile and 100 as the 97·5th percentile of 1000 draws calculated from 1990 to 2030, and took the geometric mean of the scaled indicators by target. To generate projections through 2030, we used a forecasting framework that drew estimates from the broader GBD study and used weighted averages of indicator-specific and country-specific annualised rates of change from 1990 to 2017 to inform future estimates. We assessed attainment of indicators with defined targets in two ways: first, using mean values projected for 2030, and then using the probability of attainment in 2030 calculated from 1000 draws. We also did a global attainment analysis of the feasibility of attaining SDG targets on the basis of past trends. Using 2015 global averages of indicators with defined SDG targets, we calculated the global annualised rates of change required from 2015 to 2030 to meet these targets, and then identified in what percentiles the required global annualised rates of change fell in the distribution of country-level rates of change from 1990 to 2015. We took the mean of these global percentile values across indicators and applied the past rate of change at this mean global percentile to all health-related SDG indicators, irrespective of target definition, to estimate the equivalent 2030 global average value and percentage change from 2015 to 2030 for each indicator. Findings: The global median health-related SDG index in 2017 was 59·4 (IQR 35·4–67·3), ranging from a low of 11·6 (95% uncertainty interval 9·6–14·0) to a high of 84·9 (83·1–86·7). SDG index values in countries assessed at the subnational level varied substantially, particularly in China and India, although scores in Japan and the UK were more homogeneous. Indicators also varied by SDI quintile and sex, with males having worse outcomes than females for non-communicable disease (NCD) mortality, alcohol use, and smoking, among others. Most countries were projected to have a higher health-related SDG index in 2030 than in 2017, while country-level probabilities of attainment by 2030 varied widely by indicator. Under-5 mortality, neonatal mortality, maternal mortality ratio, and malaria indicators had the most countries with at least 95% probability of target attainment. Other indicators, including NCD mortality and suicide mortality, had no countries projected to meet corresponding SDG targets on the basis of projected mean values for 2030 but showed some probability of attainment by 2030. For some indicators, including child malnutrition, several infectious diseases, and most violence measures, the annualised rates of change required to meet SDG targets far exceeded the pace of progress achieved by any country in the recent past. We found that applying the mean global annualised rate of change to indicators without defined targets would equate to about 19% and 22% reductions in global smoking and alcohol consumption, respectively; a 47% decline in adolescent birth rates; and a more than 85% increase in health worker density per 1000 population by 2030. Interpretation: The GBD study offers a unique, robust platform for monitoring the health-related SDGs across demographic and geographic dimensions. Our findings underscore the importance of increased collection and analysis of disaggregated data and highlight where more deliberate design or targeting of interventions could accelerate progress in attaining the SDGs. Current projections show that many health-related SDG indicators, NCDs, NCD-related risks, and violence-related indicators will require a concerted shift away from what might have driven past gains—curative interventions in the case of NCDs—towards multisectoral, prevention-oriented policy action and investments to achieve SDG aims. Notably, several targets, if they are to be met by 2030, demand a pace of progress that no country has achieved in the recent past. The future is fundamentally uncertain, and no model can fully predict what breakthroughs or events might alter the course of the SDGs. What is clear is that our actions—or inaction—today will ultimately dictate how close the world, collectively, can get to leaving no one behind by 2030.
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| 4. |
- Murray, Christopher J. L., et al.
(författare)
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Population and fertility by age and sex for 195 countries and territories, 1950–2017: a systematic analysis for the Global Burden of Disease Study 2017
- 2018
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Ingår i: The Lancet. - 1474-547X .- 0140-6736. ; 392:10159, s. 1995-2051
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Tidskriftsartikel (refereegranskat)abstract
- Background: Population estimates underpin demographic and epidemiological research and are used to track progress on numerous international indicators of health and development. To date, internationally available estimates of population and fertility, although useful, have not been produced with transparent and replicable methods and do not use standardised estimates of mortality. We present single-calendar year and single-year of age estimates of fertility and population by sex with standardised and replicable methods. Methods: We estimated population in 195 locations by single year of age and single calendar year from 1950 to 2017 with standardised and replicable methods. We based the estimates on the demographic balancing equation, with inputs of fertility, mortality, population, and migration data. Fertility data came from 7817 location-years of vital registration data, 429 surveys reporting complete birth histories, and 977 surveys and censuses reporting summary birth histories. We estimated age-specific fertility rates (ASFRs; the annual number of livebirths to women of a specified age group per 1000 women in that age group) by use of spatiotemporal Gaussian process regression and used the ASFRs to estimate total fertility rates (TFRs; the average number of children a woman would bear if she survived through the end of the reproductive age span [age 10–54 years] and experienced at each age a particular set of ASFRs observed in the year of interest). Because of sparse data, fertility at ages 10–14 years and 50–54 years was estimated from data on fertility in women aged 15–19 years and 45–49 years, through use of linear regression. Age-specific mortality data came from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2017 estimates. Data on population came from 1257 censuses and 761 population registry location-years and were adjusted for underenumeration and age misreporting with standard demographic methods. Migration was estimated with the GBD Bayesian demographic balancing model, after incorporating information about refugee migration into the model prior. Final population estimates used the cohort-component method of population projection, with inputs of fertility, mortality, and migration data. Population uncertainty was estimated by use of out-of-sample predictive validity testing. With these data, we estimated the trends in population by age and sex and in fertility by age between 1950 and 2017 in 195 countries and territories. Findings: From 1950 to 2017, TFRs decreased by 49·4% (95% uncertainty interval [UI] 46·4–52·0). The TFR decreased from 4·7 livebirths (4·5–4·9) to 2·4 livebirths (2·2–2·5), and the ASFR of mothers aged 10–19 years decreased from 37 livebirths (34–40) to 22 livebirths (19–24) per 1000 women. Despite reductions in the TFR, the global population has been increasing by an average of 83·8 million people per year since 1985. The global population increased by 197·2% (193·3–200·8) since 1950, from 2·6 billion (2·5–2·6) to 7·6 billion (7·4–7·9) people in 2017; much of this increase was in the proportion of the global population in south Asia and sub-Saharan Africa. The global annual rate of population growth increased between 1950 and 1964, when it peaked at 2·0%; this rate then remained nearly constant until 1970 and then decreased to 1·1% in 2017. Population growth rates in the southeast Asia, east Asia, and Oceania GBD super-region decreased from 2·5% in 1963 to 0·7% in 2017, whereas in sub-Saharan Africa, population growth rates were almost at the highest reported levels ever in 2017, when they were at 2·7%. The global average age increased from 26·6 years in 1950 to 32·1 years in 2017, and the proportion of the population that is of working age (age 15–64 years) increased from 59·9% to 65·3%. At the national level, the TFR decreased in all countries and territories between 1950 and 2017; in 2017, TFRs ranged from a low of 1·0 livebirths (95% UI 0·9–1·2) in Cyprus to a high of 7·1 livebirths (6·8–7·4) in Niger. The TFR under age 25 years (TFU25; number of livebirths expected by age 25 years for a hypothetical woman who survived the age group and was exposed to current ASFRs) in 2017 ranged from 0·08 livebirths (0·07–0·09) in South Korea to 2·4 livebirths (2·2–2·6) in Niger, and the TFR over age 30 years (TFO30; number of livebirths expected for a hypothetical woman ageing from 30 to 54 years who survived the age group and was exposed to current ASFRs) ranged from a low of 0·3 livebirths (0·3–0·4) in Puerto Rico to a high of 3·1 livebirths (3·0–3·2) in Niger. TFO30 was higher than TFU25 in 145 countries and territories in 2017. 33 countries had a negative population growth rate from 2010 to 2017, most of which were located in central, eastern, and western Europe, whereas population growth rates of more than 2·0% were seen in 33 of 46 countries in sub-Saharan Africa. In 2017, less than 65% of the national population was of working age in 12 of 34 high-income countries, and less than 50% of the national population was of working age in Mali, Chad, and Niger. Interpretation: Population trends create demographic dividends and headwinds (ie, economic benefits and detriments) that affect national economies and determine national planning needs. Although TFRs are decreasing, the global population continues to grow as mortality declines, with diverse patterns at the national level and across age groups. To our knowledge, this is the first study to provide transparent and replicable estimates of population and fertility, which can be used to inform decision making and to monitor progress. Funding: Bill & Melinda Gates Foundation.
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| 5. |
- Nawaz, Sohail, et al.
(författare)
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Antioxidant activity in aluminium oxide - Poly(ethylene-co-butyl acrylate) nanocomposites
- 2012
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Ingår i: Polymer degradation and stability. - : Elsevier BV. - 0141-3910 .- 1873-2321. ; 97:6, s. 1017-1025
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Tidskriftsartikel (refereegranskat)abstract
- The antioxidant activity of Irganox 1010 (0.2 wt%) in aluminium oxide (2-12 wt%) - poly(ethylene-co-butyl acrylate) nanocomposites was studied. The aluminium oxide nanoparticles were in three different forms: uncoated and coated with either octyltriethoxysilane or aminopropyltriethoxysilane. The activity of the stabilizer in the nanocomposites was assessed by determining the oxidation induction time (OIT) using DSC. Composites with untreated aluminium oxide nanoparticles showed a much shorter OIT than the pristine polymer with the same overall antioxidant concentration indicating adsorption of the antioxidant onto the nanoparticle surfaces. The adsorption of antioxidant onto both uncoated and coated nanoparticles was confirmed by X-ray photoelectron spectroscopy. Composites containing coated nanoparticle fillers showed a significantly smaller depression of the OIT, indicating that the replacement of hydroxyl groups with organic silane tails decreased the concentration of available adsorption sites on the particle surfaces. Composites with a filler coated with a silane having terminal aliphatic amine groups showed an increased OIT with respect to that of the pristine polymer suggesting a synergistic on the stability effect between the antioxidant and the amine groups. The long-term activity of the stabilizer was assessed by measuring the OIT on samples after ageing in air at 90°C for 720 h. The decrease in OIT with increasing ageing time of the nanocomposites was slower than for the unfilled polymer. A possible interpretation of these data is that the antioxidant was slowly released from the adsorption sites on extended ageing.
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| 6. |
- Nawaz, Sohail, et al.
(författare)
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Migration and chemical consumption of deltamethrin and piperonyl butoxide from polyethylene in aqueous media
- 2013
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Ingår i: Polymers from Renewable Resources. - : SAGE Publications. - 2041-2479 .- 2045-1377. ; 4:1, s. 1-18
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Tidskriftsartikel (refereegranskat)abstract
- Deltamethrin (DM), an important insecticide (synthetic pyrethroid) together with synergist piperonyl butoxide (PBO), is used for food storage and insect control purposes. It is often impregnated in polymers for controlled and effective release of insecticide. The migration and chemical consumption of DM and PBO from moulded polyethylene sheets was studied. The thermal behaviour of pristine DM and the prepared polyethylene compound was studied by differential scanning calorimetry. DM did not crystallize and remained in a liquid state after cooling to room temperature. Evaporation rates and activation energies of evaporation were determined by thermogravimetry for pristine DM, PBO, a solution of DM and PBO and for the PE compound. Evaporation from the DM/PBO solution was greater than that predicted from the evaporation rates of the individual compounds, which suggested that the DM/PBO solution obeyed non-ideal solution properties. The migration of DM and PBO from the polyethylene was studied in liquid water at 80 and 95 °C and in air of different relative humidities (60 and 80%) at 80 °C. Exposure to liquid water caused degradation and hydrolysis of the ester bond in DM, present in the prepared material, and generated species containing hydroxyl groups. Liquid chromatography and infrared spectroscopy showed a significant migration of the active species in liquid water, whereas the loss of DM and PBO in air at 80°C (60 and 80 %RH) was negligible over 30 days.
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| 7. |
- Nawaz, Sohail, et al.
(författare)
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Migration of a phenolic antioxidant from aluminium oxide-poly(ethylene-co- butyl acrylate) nanocomposites in aqueous media
- 2013
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Ingår i: Polymer degradation and stability. - : Elsevier BV. - 0141-3910 .- 1873-2321. ; 98:2, s. 475-480
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Tidskriftsartikel (refereegranskat)abstract
- The migration of a phenolic antioxidant (Irganox 1010) from nanocomposites based on aluminium oxide (2-12 wt.%; uncoated or coated with aminopropyltriethoxysilane or octyltriethoxysilane) and poly(ethylene-co-butyl acrylate) (EBA) with 13 wt.% butyl acrylate nanocomposites in aqueous media (liquid water or air with 100%RH) at 90°C was studied. The concentration of effective antioxidant in the composites was assessed by the oxidation induction time (OIT) measured by DSC. The flat OIT-profiles through the materials showed that the migration was controlled by the boundary conditions. The boundary antioxidant loss rates to the different media were (in relative units): 1 (dry air; data reported earlier), 1.5-3 (humid air) and 4-10 (liquid water). OIT-profiles for two-layer sandwich samples (a pristine EBA layer and a nanocomposite layer containing 0.2 wt.% Irganox 1010) showed that the antioxidant diffusivity was lowest in the composites containing uncoated nanoparticles (which had the highest surface concentration of hydroxyl groups of all the studied nanoparticles). The presence of water in the composites had only a small effect on the diffusivity; it was 10-50% greater than in the dry systems.
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| 8. |
- Nawaz, Sohail, 1984-
(författare)
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Preparation and long-term performance of poly(ethylene-co-butyl acrylate) nanocomposites and polyethylene
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The current study discusses the preparation and long-term performance of polymer composites used for various purposes under different ageing conditions.The first part deals with the preparation and characterization of polymer nanocomposites based on poly(ethylene-co-butyl acrylate) (EBA–13 and EBA–28 with 13 and 28 wt % butyl acrylate, respectively) and 2–12 wt % (0.5–3 vol %) of aluminum oxide nanoparticles (two types with different specific surface areas and different hydroxyl-group concentrations; uncoated and coated with, respectively, octyltriethoxysilane and aminopropyltriethoxysilane). The nanocomposite with EBA–13 showed better overall nanoparticle dispersion while EBA–28 resulted in poor dispersion, probably due to insufficiently high shear forces acting during extrusion mixing which were unable to break down nanoparticle agglomerates.The activity of hindered phenolic antioxidant (0.2 wt%) in all EBA nanocomposites was assessed by determining the oxidation induction time using DSC. The composites containing uncoated aluminium oxide nanoparticles showed a much shorter initial OIT than the pristine polymer with the same initial concentration of antioxidant, indicating adsorption of antioxidant onto the nanoparticle surfaces. Composites containing coated nanoparticles showed a significantly smaller decrease in the initial OIT, suggesting the replacement of hydroxyl groups with organic silane tails, decreasing the concentration of available adsorption sites on the nanoparticle surfaces. The decrease in OIT with increasing ageing time in dry air at 90 °C of the nanocomposites was slower thanthat of the unfilled pristine polymer, suggesting a slow release of antioxidant from adsorption sites.The EBA nanocomposites exposed to liquid water at 90°C showed faster decrease of OIT than samples exposed to dry or humid air. The migration rate of antioxidant was controlled by the boundary conditions in the case of ageing in humid air and liquid water. The antioxidant diffusivity was lower for the composites containing uncoated ND than for the composites containing ND coated with octyltriethoxysilane or aminopropyltriethoxysilane.The migration and chemical consumption of deltamethrin DM, (synthetic pyrethroid) and synergist piperonyl butoxide from molded polyethylene sheets was also studied. Deltamethrin and piperonyl butoxide are often used for food storage and insect control purposes. DM showed no signs of crystallization and remained in a liquid state after being cooled to room temperature. Exposure of polyethylene compound sheets to liquid water (at 80 & 95 °C), caused degradation and hydrolysis of the ester bond in the DM, present in the prepared material, and generated species containing hydroxyl groups. Liquid chromatography and infrared spectroscopy showed a significant migration of the active species in liquid water, whereas in air at 80 °C (60 and 80 %RH) the loss of DM and PBO was negligible over 30 days.The long-term performance of medium-density polyethylene stabilized with six different phenolic antioxidants (0.1 wt%) in aqueous chlorinated media at 70 °C was studied. The results were compared with data for previously studied solutions of antioxidants in squalane (a liquid, low molar mass analogue of polyethylene). A linear relationship was established between the time to reach antioxidant depletion in polyethylene tape samples and the time in squalane samples. Infrared spectroscopy and scanning electron microscopy of drawn samples revealed the onset of surface oxidation and surface embrittlement in tape samples exposed beyond the time for antioxidant depletion.
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| 9. |
- Nawaz, Sohail, et al.
(författare)
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Stabilizer activity in Al2O3/ poly(ethylene-co-butylacrylate) nanocomposites
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Ingår i: Polymer degradation and stability. - 0141-3910 .- 1873-2321.
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The stabilizer activity of polymer nanocomposites based on poly(ethylene-co-butylacrylate) and 0.5 - 3 vol. % of two different types of Al2O3 nanoparticles was investigated. The nanoparticles were either functionalized using octyl- or amino-terminated silanes, or used as received. The nanocomposites also contained 0.2 wt. % of Irganox 1010, a hindered phenolic stabilizer. The activity of the stabilizer in the samples was analyzed by Differential Scanning Calorimetry (assessment of Oxidation Induction Time (OIT)), and compared those obtained for the pristine polymers. The stabilizer was adsorbed to the untreated Al2O3 nanoparticles resulting in a significant reduction in OIT. The reduction increased with increasing total surface area of the particles. Surface silanization of the nanoparticles resulted in an increase in OIT, compared to the untreated particles. The activity of the stabilizer was evaluated by OIT after thermal ageing of the nanocomposites in hot-air oven at 90C up to 30 days. No surface oxidation was observed on any of the samples using reflection infrared spectroscopy. The ageing showed that the stabilizer was not irreversibly adsorbed to the particle surfaces, resulting in a gradual release with the ageing time. This resulted in a slower reduction in OIT as function of aging time for the nanocomposites, compared to the pristine polymer. In order for the nanocomposites to exhibit similar or higher OIT values after thermal ageing, compared to unfilled EBA, > 0.5 mg of stabilizer per m2 of octyl- or amine-coated Al2O3 nanoparticles was needed. The loss of stabilizer was controlled by the evaporation rate of the stabilizer from the surface of the samples to the surrounding air.
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| 10. |
- Nordell, Patricia, et al.
(författare)
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Preparation and characterization of aluminum oxide-poly(ethylene-co-butyl acrylate) nanocomposites
- 2012
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Ingår i: Journal of Applied Polymer Science. - : Wiley. - 0021-8995 .- 1097-4628. ; 125:2, s. 975-983
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Tidskriftsartikel (refereegranskat)abstract
- This article describes the preparation and characterization of composites containing poly(ethylene-co-butyl acrylate) (EBA13 and EBA28 with 13 and 28 wt % butyl acrylate, respectively) and 212 wt % (0.53 vol %) of aluminum oxide nanoparticles (two types differing in specific surface area and hydroxyl-group concentration; uncoated and coated with, respectively, octyltriethoxysilane and aminopropyltriethoxysilane). A greater surface coverage was obtained with aminopropyltriethoxysilane than with octyltriethoxysilane. An overall good dispersion was obtained in the EBA-13 composites prepared by extrusion compounding. Composites with octyltriethoxysilane-coated nanoparticles showed the best dispersion. The addition of the nanoparticles to EBA28 resulted in poor dispersion, probably due to insufficiently high shear forces acting during extrusion mixing which were unable to break down nanoparticle agglomerates. The nanoparticles had no effect on the crystallization kinetics in the EBA13 composites, but in the EBA28 composites the presence of the nanoparticles led to an increase in the crystallization peak temperature, suggesting that the nanoparticles had a nucleating effect in this particular polymer.
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