1. elektronické vydání 1 online zdroj (206 stran)
Kniha se zabývá vybranými aspekty německé menšiny v Olomouci v době první ČSR. Zaobírá se i demografickými poměry ve městě se zvláštním zaměřením na národnostní vztahy. Hlavní část knihy je věnována Němcům a česko-německým vztahům v komunální politice. V této části je sledován chronologický vývoj komunální politiky.; Kniha se zabývá vybranými aspekty německé menšiny v Olomouci v době první ČSR. Zaobírá se i demografickými poměry ve městě se zvláštním zaměřením na národnostní vztahy. Hlavní část knihy je věnována Němcům a česko-německým vztahům v komunální politice. V této části je sledován chronologický vývoj komunální politiky. Stručně jsou popsány i životopisy jednotlivých aktérů německé politiky. Spolkový život je představen na ukázce několika německých spolků. V knize je představený i německojazyčný periodický tisk. Dále jsou popsány konflikty ve školství, vývoj německého školství, školská správa a systém německých škol ve městě. Stručně je představena i činnost Německé veřejné knihovny.
The paper describes transesterification of oil by methanol with use of cosolvents such as ethyl acetate, tetrahydrofuran, hexane, acetone and diethyl ether at catalyst homogeneous (potassium hydroxide) and heterogeneous (mixed oxides). The cosolvents dissolve oil and methanol to form a single (homogeneous) phase, which increases the reaction rate. Therefore, the biodiesel production will be environmentally friendly because less energy is consumed, which increases sustainability. The whole binodal curve of ternary plots of oil, methanol and cosolvent was determined to find the molar ratio, in which the reaction mixture forms a single phase. The ethyl acetate and tetrahydrofuran have relatively small heterogeneous region, because of the similarity of their electric dipole moment with methanol. After transesterification, the detailed analysis of ester and also glycerol phase was carried out. For homogeneous catalyst, the highest esters content in the ester phase was achieved with tetrahydrofuran. For heterogeneous catalyst, the ester content was lower with cosolvent than without cosolvent, probably due to dilution of reaction components by cosolvent or bonding of cosolvent to the active sites of the catalyst.
- MeSH
- biopaliva * MeSH
- esterifikace MeSH
- estery * MeSH
- katalýza MeSH
- methanol MeSH
- oleje rostlin MeSH
- Publikační typ
- časopisecké články MeSH
The effects of phase separation temperatures (5-90°C) on losses of higher fatty acid (C(16) and C(18)) ethyl esters in the glycerol phase were investigated. Losses of ethyl esters produced from ethanolysis of rapeseed oil were 30-60% higher when NaOH rather than KOH was used as homogeneous catalyst. The losses decreased with an increase in separation temperature, resulting in an increase in the yield of the ester phase. The concentration of impurities (e.g. alkali metals, free glycerol and glycerides) in the ester phase increased with increasing separation temperature due reversible transesterification and reciprocal solubility of the compounds. Carbonates formed during neutralization of the catalysts are also transesterification catalysts and they cause reverse reaction. The ethyl ester bound in the glycerol phase during NaOH-mediated catalysis can be extracted by heating the separated glycerol phase to 60-90°C. The ester yield is increasing with increasing separation temperature, however with decreasing quality.
Glycerol is a by-product of biodiesel produced by transesterification and is contained in the glycerol phase together with many other materials such as soaps, remaining catalyst, water, and esters formed during the process. The content of glycerol is approximately 30-60 wt.%. In this paper, treatments of the glycerol phase to obtain glycerol with a purity of 86 wt.% (without distillation) and a mixture of fatty acids with esters (1:1) or only a mixture of fatty acids with a purity of 99 wt.% are presented. The treatment was carried out by removing of alkaline substances and esters. Fatty acids were produced by saponification of the remaining esters and subsequent neutralization of alkaline substances by phosphoric, sulfuric, hydrochloric, or acetic acids. Salts are by-products and, in the case of phosphoric acid can be used as potash-phosphate fertilizer. The process of treatment is easy and environmentally friendly, because no special chemicals or equipment are required and all products are utilizable.
The Chad Basin lies in the middle of the Sudanic African belt between the Sahara and the tropical rain forests. Its present-day settlement is a result of Holocene climatic changes and human immigrations from different parts of Africa. This study presents a statistical analysis of the relationships of physical features (stature and five main craniofacial measurements) and mitochondrial (mtDNA) haplogroup classifications in a sample of 282 adult individuals belonging to seven populations of different ethno-linguistic groups living in the Chad Basin. Drawing on the analysis of variance, we identified a female-specific DNA association between mtDNA haplogroup assignment and facial height. More specifically, the mtDNA haplogroups of East-African origin occur more frequently in females with relatively longer faces and, conversely, the mtDNA of West-African origin are found more frequently in females with lower faces. Interestingly, this kind of association is not found in the males of the same populations. Our interpretation refers mainly to population history; we suggest that facial height and mtDNA haplogroup co-variance in Chad Basin females reflects a long-term east-west population distribution in the past that made the facial differentiation possible. Copyright 2008 Wiley-Liss, Inc.
- MeSH
- antropometrie MeSH
- dospělí MeSH
- financování organizované MeSH
- haplotypy MeSH
- kefalometrie MeSH
- lebka anatomie a histologie MeSH
- lidé středního věku MeSH
- lidé MeSH
- maxilofaciální vývoj fyziologie genetika MeSH
- mitochondriální DNA analýza MeSH
- obličej anatomie a histologie MeSH
- pilotní projekty MeSH
- populační dynamika MeSH
- populační genetika MeSH
- referenční hodnoty MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Geografické názvy
- subsaharská Afrika MeSH
- Súdán MeSH
