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Accelerated hydrolysis of PLA fibers at low temperature
No full textThe polylactide (PLA) is the most common biodegradable material. However, its biodegradation requires hydrolysis of PLA to oligomers or monomers before microbes can act. Hydrolytic degradation of PLA depends on temperature, time and relative humidity. It takes months and years until complete biodegradation. If a catalyst is introduced, i.e. alkali or alcohol, it can be done in weeks. In this article, the alkaline hydrolysis was performed at low temperatures 40-60°C without and with the addition of cationic compound as an accelerator for the purpose of saving energy and time for complete PLA degradation. It has been shown that complete degradation can be achieved in only 10 min at 40°C
Ocena zawartości srebra w wybranej grupie wyrobów biomedycznych metodą atomowej spektroskopii absorpcyjnej
No full textThermal behavior of a multi-layer laminated fabric containing PCMS
No full textPhase change material (PCM)-incorporated fabrics have been developed for personal temperature
regulation. To avoid leakage of melting PCMs from the fabric, various methods have been developed,
including microencapsulated PCM (MPCMs), form-stable PCMs (FSPCMs) and solid-solid PCMs
(SSPCMs). However, the poor physical property and the limited thermal behavior of such materials are
found. To keep the thermal behavior of PCM-incorporated fabrics without leakage as high as possible,
a multi-layer PCM fabric consisting of PEG-coated viscose fabric and PA 6-laminated fabric was
proposed in this work. The leakage and thermal buffering effect of the multi-layer laminated fabric
containing PEG were investigated. As a result, the PA 6-laminated fabric successfully resisted against
the melting of PEG and no leakage was found. Correspondingly, the thermal buffering effect was found.
We propose that this work provides a facile method to fabricate PCM fabrics and extends the application
of laminated fabrics
Lit night, a clear threat to nature - ALAN'S impact on migratory birds
No full textNegatywne oddziaływanie sztucznego oświetlenia (Artificial Light
at Night – ALAN) jest jedną z głównych, antropogenicznych przyczyn odpowiedzialnych
za bezpośrednią śmiertelność ptaków migrujących nocą. Do
udokumentowanego, negatywnego wpływu ALAN na ptaki zaliczane są: efekt
przyciągania i efekt dezorientacji. Efekt bariery z kolei jest przedmiotem badań,
jednak brakuje jak dotąd jednoznacznego stwierdzenia na temat charakteru
tego zjawiska. Większość badań wskazuje, że za efekt przyciągania,
przyczyniający się do kolizji z różnymi konstrukcjami na lądzie i na morzu,
odpowiedzialne jest oświetlenie o barwie niebieskiej i zielonej. Jednak
czerwone i białe światło również wskazywane było w badaniach jako
wywierające wpływ na przyciąganie ptaków. Z uwagi na te rozbieżności,
konieczne są dalsze badania, w efekcie których będzie możliwe określenie, jaka
barwa światła będzie najbezpieczniejsza dla ptaków. W chwili obecnej zasadne
wydaje się rekomendowanie wykorzystania źródeł światła o barwach ciepłych
(żółtej, bursztynowej) o temperaturze barwowej nieprzekraczającej 3000 K.The negative impact of excessive artificial light at night (ALAN)
affects birds migrating nocturnally, and is one of the major causes of direct
mortality of birds due to human activities. Among the recognized negative
impacts of ALAN on migratory birds are: attraction, disorientation, and barrier
effects. The nature of these impacts can directly affect mortality rates as well
as contribute to them indirectly by increasing energy expenditure during
migration as a result of disorientation and migration route changes. The
majority of studies indicate that the effect of attraction, and therefore
mortality, for both land and offshore structures is significantly greater with
blue and green light, however, there are papers indicating greater bird
attraction to red and white light. Because of these discrepancies, further
research is needed to answer what color of the light (wavelength) is most
important in attracting migratory birds to the ALAN source. At present, we
recommend the use of warm-colored lights with a maximum temperature of
3,000 K
Effect of knit stitches percentage on physical parameters of weft-knitted fabrics
No full textIn this study 100% cotton 29.5 tex yarn was used to develop hybrid knitted structures with a combination
of knit, tuck and miss stitches. A single jersey circular weft machine (FUKUHARA, Japan, 1992) with
diameter 30 inches and gauge 20E was used to develop the samples. The samples were scoured,
bleached, dyed, and treated with softener. The physical properties of the samples, e.g. area density,
thickness, and wale and course density were determined according to the standard test methods. It was
concluded from the analysis of results that fabric area density and thickness were found to depend on
the percentage of different stitches in the fabric structure
Evaluation the resistance of pre-deformed multi-layer 3D fabrics against knife penetration
No full textThe high-performance fibres are employed largely as reinforced polymer fabrics and composites in the
flexible and stiff stab-resistant personal protection equipment. To simulate the knife attack on the human
body, a new methodology named pre-deformed stabbing is developed to characterise the stab
performance taking into account the fabric’s deformations. Three-dimensional warp interlock fabrics
(3DWIFs) were manufactured using high-molecular-weight polyethylene (HMWPE) yarns. The
forming was performed on the tested 3DWIFs before the stabbing. The stabbing results are influenced
by the different mode deformations created during the forming. Based on the in-plane shearing map,
three different stabbing locations were chosen. The effect of locations on the stab resistance of 3DWIFs
was explored with the same impact energy level. The effect of stabbing localization on the deformed
fabric is significant. The shear-locking angle in the location area is critical for the stab resistance of both
[0°/90°]8 and [0°/90°, -45°/45°]4 deformed fabrics in the studied cases
Organizational Learning Based on Scrum Teams
No full textIn recent years, the dominant approach in the IT industry has become an agile
approach to both project and enterprise management. In order to increase
their flexibility, companies related to the production of IT products have declared
and adopted actions according to the Scrum methodology.
A survey carried out on the representatives of the population of IT companies
allows for indicating companies’ actual activities in the Scrum methodology.
The questions posed concern both implementing the assumptions of this methodology
and the activities and characteristics of the learning organization.
This allows for the analysis of the correlation between these two factors
A review of lcam datasets and sève whiteness proposal
No full textIn our recent work, we investigated the validity of the newly proposed whiteness formula by Robert
Sève [1] for our LCAM whiteness datasets under a LED light source of correlated color temperature
(CCT) 5000K combined with Wood's UV-A lamp.We compared the CIE whiteness formula, the Ganz
whiteness formula, and the Séve proposal to the results of visual assessment of forty white samples
assessed by ten observers with normal color vision under experimental light source. Because the Sève
proposal was derived from the CIE formula for whiteness considering whitespace, we were interested
to see its impact on our datasets under test lighting different from D65.We have found that the Sève
whiteness formula can predict maximum whiteness as a function of saturation for light conditions other
than CIE D65, but visual observations of whiteness lead to an assessment of a significant drop in
whiteness for materials with saturation between - 40 and -70 and luminance factor between 70 and 90.
As expected, both the CIE whiteness formula and the Ganz formula correlated strongly with visual
observations. In the case of the CIE equation, a high correlation coefficient of 0.84 was measured
compared to the newly proposed W2,n equation where a value of 0.71 was found. In other words, with a
very intense UV source, the intensity of which is above the UV fraction of the corresponding CIE
illuminations D, the colouration of the samples containing FWA is highly saturated. This fact is not
taken into account in the case of the CIE equation. Dr. Sève's new proposal addresses this problem, but
sufficient new visual experiments need to be set up so that the parameters of this equation can be
optimised