| 1. |
|
|
| 2. |
- Bentham, James, et al.
(författare)
-
A century of trends in adult human height
- 2016
-
Ingår i: eLIFE. - : eLife Sciences Publications Ltd. - 2050-084X. ; 5
-
Tidskriftsartikel (refereegranskat)abstract
- Being taller is associated with enhanced longevity, and higher education and earnings. We reanalysed 1472 population-based studies, with measurement of height on more than 18.6 million participants to estimate mean height for people born between 1896 and 1996 in 200 countries. The largest gain in adult height over the past century has occurred in South Korean women and Iranian men, who became 20.2 cm (95% credible interval 17.5–22.7) and 16.5 cm (13.3– 19.7) taller, respectively. In contrast, there was little change in adult height in some sub-Saharan African countries and in South Asia over the century of analysis. The tallest people over these 100 years are men born in the Netherlands in the last quarter of 20th century, whose average heights surpassed 182.5 cm, and the shortest were women born in Guatemala in 1896 (140.3 cm; 135.8– 144.8). The height differential between the tallest and shortest populations was 19-20 cm a century ago, and has remained the same for women and increased for men a century later despite substantial changes in the ranking of countries.
|
|
| 3. |
|
|
| 4. |
- Tran, Khanh-Quang, 1962, et al.
(författare)
-
A kinetic study of gaseous alkali capture by kaolin in the fixed bed reactor equipped with an alkali detector
- 2005
-
Ingår i: Fuel. - 0016-2361. ; 2-3, s. 169-175
-
Tidskriftsartikel (refereegranskat)abstract
- In this study, the interaction between gas phase potassium species and kaolin was investigated in a fixed bed reactor equipped with a surface ionization detector, which is capable of detecting alkali metals in gas phase at ppb level. The effects of mass transport, space time, sorbent temperature and concentration of KCl on the rate of potassium adsorption on kaolin were studied in air. Kaolin, mainly composed of kaolinite-Al2Si2O5(OH)(4), was found to be very efficient in removing gaseous alkali species from hot flue gases at fluidized bed combustion temperatures. The removal efficiency increased as temperature was decreased or KCl concentration was increased. The capture of potassium by kaolin was irreversible with formation of both water-soluble and water-insoluble products. Kaolin captured KOH almost as effectively as KCl, but K2SO4 was captured much less effectively than KCl. (C) 2004 Elsevier Ltd. All rights reserved.
|
|
| 5. |
|
|
| 6. |
|
|
| 7. |
|
|
| 8. |
|
|
| 9. |
- Tran, Khanh-Quang, 1962
(författare)
-
Measurement and Control of Metal Vapours during Fluidized Bed Combustion of Biomass Fuels
- 2004
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Increased combustion of biomass fuels for heat and power production has created a need to recycle nutrient elements in biomass ash to soils to make the biomass consumption sustainable. It is, however, difficult to recycle the total amount of biomass ash produced due to the high concentrations of heavy metals and their readily soluble forms in some ash fractions. In addition, alkali metals in biomass fuels are directly responsible for problems of fouling and bed agglomeration during the combustion of biomass fuels in fluidized bed combustion (FBC) boilers. Therefore, to understand and control the fate of both alkali and heavy metals in the process is of great importance and the central issue in this thesis. The first part of the thesis deals with further developments of the gas quenching (GQ) probe for measurement of metal vapours in FBC conditions. A new version of the probe with a sintered quartz filter incorporated in a quartz tube module for excluding solid particles from the sampled gas has been constructed and evaluated through field measurements of cadmium in a full-scale FBC research boiler. The results are promising, indicating that the technique can be a valuable tool to characterise the presence of gaseous metal species and obtain mass balances in FBC processes. In addition, a novel particle impactor has been developed for use with the GQ probe instead of the filter. The impactor has been tested at room temperature and gave very sharp cut-off curves with a maximum collection efficiency of about 0.9 and a cut-off size square root of Stk50 of about 0.22. The efficiency of the impactor was compared with the efficiency of a sintered quartz filter of the same type as the filter previously used with the GQ probe. The difference is very small, indicating that the impactor can be used with the GQ probe in FBC conditions. In the second part of the thesis, capture of alkali and/or heavy metals on kaolin in oxidizing or reducing conditions has been investigated in a fixed bed reactor equipped with an on-line alkali detector. Kaolin was found to capture potassium vapours irreversibly and effectively in both oxidizing and reducing conditions. Kaolin captures cadmium in air, but not in reducing conditions. In air, the process was determined to be of a reaction order 1.5 with a rate constant k = 5.2 x 108 cm3 gas/cm3 solid-hr at 850°C, with respect to the KCl concentration in the gas phase. A reducing atmosphere appears to promote the reaction between gaseous potassium species and kaolin, compared to the oxidizing atmosphere. Co-presence of potassium and cadmium compounds promotes the capture of both metals on kaolin in oxidizing conditions. This promotion was more pronounced for potassium than for cadmium, indicating that potassium capture by kaolin is more favourable than cadmium capture. Overall, kaolin is suitable for in-situ and selective removal of alkali during combustion of biomass fuel in FBC conditions.
|
|
