J i ř í LU K A S , P o k u s o r e k o n s t r u k c i n á l e z u , s . 2 6 – 2 8
Reconstruction attempt in the case of the hoard of the deniers dating back to the
10th century found near Ústí nad Labem (Based on hand-written notes by E. Fiala)
The article offers a partial reconstruction attempt focused on the hoard of the
Bohemian deniers struck under Boleslaus II (972–999) discovered in the
surroundings of Ústí nad Labem sometimes before 1895. The reconstruction is
based on analysis of older literature and the hand-written notes produced by the
J i ř í LU K A S , N o v é e x e m p l á ř e m o r a v s k é h o d e n á r u , s . 1 2 8 – 1 4 1
New Moravian deniers of the C 301 type struck under Břetislaus I and found at
the Vraclav hillfort
Two fragments of extraordinarily rare Moravian deniers of the C 301 type
struck under Břetislaus I before 1030 were found during archaeological surface
examinations at the Vraclav hillfort (Ústí nad Orlicí district, Pardubice region)
in 2006–2016. There is the name of Břetislaus without his princely title on
obverse, and the name of St. Clement, the
J a n V I D E MA N , K p o s t a v e n í t z v . i m i t a t i v n í c h r a ž e b , s . 1 0 – 2 5
Notes to the role of the so-called imitative coins at the beginning of the Bohemian
(and Moravian) coinage of the 10th century
The article is focused on problems with the so-called imitative coins, i.e. deniers
copying the Bavarian and Bohemian prototypes which are documented in hoards
together with official issues. In the case of the earliest phase of production of the first
Bohemian coins – dating to the third quarter of the 10th century – also the
This study investigates the effect of material composition on moisture management properties. Fiber type has significant influence on the moisture management properties of knitted fabrics. In this article, single jerseys knitted fabric samples with different yarn compositions were prepared. Liquid moisture transportation properties including wetting time, absorption rate, spreading speed, one-way transportation capability, and OMMC were evaluated by Moisture Management Tester (MMT) and vertical wicking was evaluated using thermography system and image analysis. Knitted sample having fine cotton yarns with coolmax and micro denier multifilament polypropylene showed best liquid transportation properties. There is a strong co-relation between OMMC and accumulative oneway transport index with vertical wicking of knitted samples.
A simple and general mathematical model has been developed to calculate filter-filtration efficiency, which is based on practical design parameters: pressure drop, filter dimension, flow rate, and filament denier. This model has been verified by examining published experimental data, which include a broad range of design parameters. This model surpasses other models currently described in the literature in terms of accuracy. The drag force of the filter (which is accounted for by the pressure drop times the circumference squared, DP • C2) appears to be the most important contribution to filter-filtration efficiency, but its contribution can be drastically reduced by varying design parameters.
The transfer of high-boiling cigarette smoke components from a filter to the trapping system was studied by adding carbon-14 labelled compounds to filters, smoking cigarettes attached to them, and determining the radioactivity which had escaped from the filter. Transfer or elution was slight when air was puffed through the filter, but appreciable when smoke was puffed through it. Elution is proposed to take place as a result of a compound's vapourizing from a fiber and, instead of recondensing on the fiber, being trapped by an aerosol particle which subsequently escapes from the filter. The effect of the properties of the compound being studied, the aerosol properties, and the filter parameters on elution were investigated. From the study of elution of several compounds on an individual-puff basis, it was found that the relative affinity between the eluted compound and the aerosol or the filter has an important influence on elution. Use of straight-chain hydrocarbons led to the conclusion that there is a linear relationship between percentage of elution and the logarithm of the vapour pressure of the compound being eluted by cigarette smoke. Decrease in aerosol concentration decreases elution; increase in filter and/or aerosol temperature increases elution. Aerosol composition can be important in elution behaviour, as in the apparent relationship between increased moisture content of the aerosol and increased elution of nicotine during the last puffs. Increase in filter length slightly decreases elution, decrease in total denier slightly decreases elution, and change in denier per filament causes no change in elution.
A number of filters were studied to determine the effect of air dilution on smoke filtration, both in well characterized acetate tow items and also in commercial filters that incorporated air dilution. A direct reduction of condensate and nicotine was observed in proportion to the degree of air dilution. Particulate filtration efficiency increased with air dilution. Gas phase delivery of aldehydes and CO decreased in greater proportion than the amount of air dilution. The commercial brands tested closely fitted the model developed in the filter tow study, except where mouthpieces or other flow channeling devices altered the filtration characteristics of the cigarette in varying degrees. Significantly, the results of the studies showed that the amount of air dilution, and not the physical means of air mixing, was the defining parameter to predict filter performance. Ventilation gives a useful design capacity that extends control of smoke filtration behaviour. By appropriate selection of tow denier per filament, total denier and cross-section shape, filter length and diameter, and the level of air dilution, filter properties can be adjusted to control gas and particulate phase deliveries, and the proportionality between the two.
The amount of particulate matter captured by the upstream and downstream segments of ventilated filters was directly determined by a UV method. With 25 mm 3.3 dpf/35000 total denier filters the dry particulate matter efficiency of the upstream section approximately doubled and the nicotine efficiency increased by about a half in going from 0 to 70 % tip ventilation. The efficiency of the downstream segment showed only minor variations. This resulted in an increase of total filtration efficiency from 48 % to 63 % for dry particulate matter and from 40 % to 49 % for nicotine. The dry particulate matter/nicotine ratio decreased from about 15 for non-ventilated cigarettes to less than 10 at 70 % tip ventilation because the tobacco column produced smoke containing relatively more nicotine and the difference between dry particulate matter and nicotine filtration efficiencies became successively larger as ventilation increased.
This study examined the mechanical properties of a para-aramid filament according to the processing conditions of air-jet textured yarns (ATY). The specimens were prepared by changing the yarn speed, over feed ratio, air pressure, and heater temperature, which are important processing factors in the ATY process. The basic physical properties of the ATY, such as denier, tenacity, breaking strain, and initial modulus, were measured and their thermal shrinkage, such as dry and wet shrinkage, were measured to determine the thermal stability of the aramid ATY. In addition, the instability of para-aramid ATY were measured and assessed with the loop formation of ATY, according to the ATY process parameters. An examination of the effects of process parameters on the physical properties of aramid ATY revealed the core overfeed and air pressure to be the main factors. A high core overfeed and air pressure make the aramid ATY crimpy in the yarn core and entangle the fluffy loops on the yarn surface, resulting in an increase in the yarn linear density and breaking strain as well as a decrease in the tenacity and initial modulus. In contrast, these yarn physical properties were unaffected by the yarn speed, heater temperature, and wetting treatment. In addition, the dry and wet thermal shrinkage were unaffected by the process parameters of ATY. On the other hand, the instability decreased with increasing core overfeed and heater temperature and increased with increasing air pressure. These results showed that a high core overfeed makes the aramid ATY crimpy with an entangled yarn structure, and high air pressure helps provide small loops on the yarn surface. Finally, a high heater temperature makes the crimpy ATY structure more stable due to the strong heat set, which results in low instability.
References Kuenen, J. H. Denier van der Gon, A. Visschedijk, H. van der Brugh , High resolution European emission inventory for the years 2003 – 2007, TNO report TNO-060-UT-2011-00588, Utrecht, 2011 European Environment Agency: The European environment – state and outlook 2010: synthesis, European Environment Agency, Copenhagen, 2010 Visschedijk, A.J.H., Zandveld, P.Y.J., Denier van der Gon , H.A.C., 2007. A High Resolution Gridded European Emission Database for the EU Integrate Project GEMS. TNO-report 2007-A-R0233/B Werner, M., Kryza, M., Ojrzyńska, H., Skjøth