Investigating biological activity spectrum for novel styrylquinazoline analogues

In this study, series of ring-substituted 2-styrylquinazolin-4(3H)-one and 4-chloro-2-styrylquinazoline derivatives were prepared. The syntheses of the discussed compounds are presented. The compounds were analyzed by RP-HPLC to determine lipophilicity. They were tested for their inhibitory activity on photosynthetic electron transport (PET) in spinach (Spinacia oleracea L.) chloroplasts. Primary in vitro screening of the synthesized compounds was also performed against four mycobacterial strains and against eight fungal strains. Several compounds showed biological activity comparable with or higher than that of the standard isoniazid. It was found that the electronic properties of the R substituent, and not the total lipophilicity of the compound, were decisive for the photosynthesis-inhibiting activity of tested compounds

Forensic Engineering of Advanced Polymeric Materials. Part 1 –Degradation Studies of Polylactide Blends with Atactic Poly[(R,S)-3-hydroxybutyrate] in Paraffin

The degradation of the advanced polymeric materials: blends of polylactide with poly[(R,S)-3-hydroxybutyrate] was studied in paraffin (an ingredient used in cosmetics) and compared with the degradation of pure poly[(R,S)-3-hydroxybutyrate]. The interaction between the polymeric materials studied and the paraffin was monitored during the degradation experiments, and the effects of this interaction were reported. Gel permeation chromatography, atomic force microscopy, electrospray mass spectrometry, nuclear magnetic resonance, differential scanning calorimetry and thermal gravimetric analysis revealed that degradation of the investigated materials occurs in the presence of paraffin. In the blends, poly[(R,S)-3-hydroxybutyrate] content was found to extend the disintegration time, and for the blends with good miscibility, reduced the degradation rate in the first step of degradation

Prediction studies of environment-friendly biodegradable polymeric packaging based on PLA. Influence of specimens’ thickness on the hydrolytic degradation profile

Application of new biodegradable polymer packaging based on polylactide (PLA), susceptible to organic recycling, can help in the waste reduction in landfills. In this paper, the results of the study on abiotic degradation of PLA and its blend containing 15 mol% of poly[(R,S)-3-hydroxybutyrate], as a model for the first step of organic recycling were presented. The samples used for this study have different shapes and thicknesses: rigid films and cuboid-bars. Particular emphasis was placed on determining the pattern of degradation products released into the medium. Originally, the results of present study revealed that the application of electrospray ionization mass spectrometry supported by high performance liquid chromatography allowed envisaging the differences in the degradation products pattern released from the studied PLA-based samples differing in thickness. The significant differences in degradation products pattern were predominately observed in the first steps of incubation process and are caused by an autocatalytic effect, which occurs mainly during degradation of the large size PLA samples. Although, the thickness of PLA-based packaging changes the degradation product patterns, however this does not increase the total amounts of acids released to the medium. Thus, it may be concluded that thickness should not affect significantly organic recycling of the packaging

Ocena możliwości zwiększenia nośności wytrzymałościowej kratownicowych mostów suwnic pomostowych

A possibility of increasing the load-carrying strength of truss bridges of overhead travelling cranes by transferring a part of a useful load from the main truss (which transfers directly the load originated from road wheels of the crane carriage) on the parallel auxiliary truss by means of increasing rigidity of truss members joining both trusses - was presented in the paper. The verification of a static relief of the main truss by the auxiliary one as a function of rigidity of transverse and skew space trusses was performed. The A. Blum method was used in analytical calculations. The obtained results were verified by means of the ANSYS 12.1 program utilising the finite element method (FEM).W artykule przedstawiono możliwość zwiększenia nośności wytrzymałościowej kratowych dźwigarów mostów suwnicowych poprzez przeniesienie części obciążenia użytkowego z kraty głównej, przenoszącej bezpośrednio obciążenie pochodzące od nacisku kół biegowych wózka suwnicowego, na równoległą kratę pomocniczą, drogą zwiększenia sztywności prętów wykratowania łączących obie kratownice. Sprawdzono statyczne odciążenie kraty głównej przez kratę pomocniczą w funkcji sztywności prętów wykratowania poprzecznego i ukośnego kratownicy przestrzennej. Do obliczeń analitycznych wykorzystano metodę A. Bluma. Otrzymane wyniki zweryfikowano przy użyciu oprogramowania ANSYS 12.1 wykorzystującego metodę elementów skończonych (MES)

Impact of modification of hydraulic leg piston design on its yield

Analizowano wpływ modyfikacji postaci konstrukcyjnej tłoka stojaka hydraulicznego, polegającej na zwiększeniu objętości przestrzeni podtłokowej, na przebieg czasowy ciśnienia cieczy roboczej oraz współczynnik sprężystości układu. W przypadku niewielkiego wysunięcia rdzennika modyfikacja postaci konstrukcyjnej tłoka skutkuje znaczącą zmianą maksymalnej wartości ciśnienia i wydłużeniem okresu jego drgań.Impact of design modification of the piston of hydraulic leg, consisting in enlarging of annular area of the leg, on time curve of working medium pressure and the coefficient of elasticity of the mechanical system, were analyzed. In case of small advance of upper prop, the design modification of the piston causes significant change of the maximum working medium pressure and extension of pressure oscillation period

Implementation of new technologies – strategy in decision making

W artykule przedstawiono postępowanie w procesie dokonywania wyboru z zakresu: produkować czy kupować (metoda make-orbuy). Jako studium przypadku posłużyła firma Profish, która jest typową firmą handlową, lecz rozważa możliwość podjęcia produkcji. W artykule została przedstawiona strategia rozwoju firmy Profish poprzez inwestycję w produkcję własną. W artykule przedstawiono koszty wytworzenia, które posłużyły do wyznaczenia punktu rentowności produkcji. Analiza wrażliwości, w której szacowany jest wpływ zmiany niektórych czynników tj. kosztów stałych, kosztów zmiennych i ceny usługi na rentowność produkcji potwierdziła opłacalność produkcji.The article presents the process of making a choice between makeor-buy. Profish company, which is a typical trading company, was used as a case study, the company considering the possibility of production. The article presents Profish's development strategy through investment in own production. The article presents manufacturing costs that have been used to determine the viability of production. Sensitivity analysis, where the impact of some factors such as fixed costs, variable costs and outsourcing prices on the profitability of production has been estimated. The Analysis has confirmed the profitability of production

AC voltage standards with calculable AC-DC transfer difference in frequency range from 10 kHz to 1 MHz

W artykule zaprezentowano konstrukcję oraz podstawowe parametry metrologiczne trzech wzorców napięcia przemiennego o liczalnej różnicy transferowej w paśmie częstotliwości 10 kHz - 1 MHz. Artykuł zawiera między innymi obliczone w oparciu o model matematyczny wartości różnic transferowych wzorców oraz niepewności ich wyznaczenia. Ponadto w pracy opisano schemat komparacji wzorców oraz teoretyczne wyniki tej komparacji.The paper presents construction and basic metrological parameters of AC voltage standards with calculable AC-DC transfer difference in the frequency range from 10 kHz to 1 MHz. Three standards cover the AC voltage range from approximately 0.7 to 6 V. Each standard is composed of a series range resistor and a single junction thermal converter (SJTC). The range resistor is made from thin resistive wire and mounted, together with the SJTC, in a coaxial copper-brass enclosure shown in Fig.1. The construction of each standard is similar to those presented in [1]. The nominal values of construction and material parameters, common for all the three standards, are listed in Table 2. The AC-DC transfer difference, given by Eq.3, was calculated using the theoretical model presented in [2], however in the calculations presented in this paper the influence of the Tee-connector was included. In Section 4 the standard uncertainty of the calculated AC-DC differences is estimated according to [3]. The relation between the calculated AC-DC differences and the frequencies of all the three standards, together with the estimated uncertainties are given in Tables 3 - 5. In Section 5 a method for verification of the calculated AC-DC transfer differences is described: the 1.5 V standard will be directly compared with the 3 V standard, and the 3 V standard will be compared with the 6 V standard. The result of such comparisons - the differences of the AC-DC transfer differences of the compared standards were theoretically calculated. They are listed in Table 6

Metrological properties of digital two-phase voltage sources

W pracy zostały przedstawione wyniki badań właściwości metrologicznych dwu wybranych komercyjnych cyfrowych dwufazowych źródeł napięcia przemiennego. Badania były prowadzone pod kątem wykorzystania tych źródeł w precyzyjnych układach służących do komparacji impedancji. Otrzymane wyniki badań wzajemnej stabilności amplitud i stabilności fazy poddanych analizie źródeł potwierdzają, iż realne jest uzyskanie niepewności komparacji wzorców impedancji na poziomie 10-5 zarówno przy wykorzystaniu w układzie generatora Tabor Electronics WW2572A, jak i źródła Audio Precision AP SYS-2722.Metrological properties of commercially available digital two-phase generators are considered in the paper. Two sinewave sources: Tabor Electronics WW2572A and Audio Precision AP SYS-2722 were examined for use in high-precision impedance comparison bridges. The relative stability of the output voltage amplitudes was tested in the measuring circuit shown in Fig. 4. All measurements were made in an electromagnetically screened room shown in Fig. 3. The results obtained (Figs. 5 and 6) prove the short-term magnitude stability of the WW2572A on the level of 15 V/V and the stability of the AP SYS-2722 better than 10 V/V. The phase shift stability was checked with use of a lock-in amplifier Stanford Research System SR830. The measurements were taken for four different phase shifts = CH1 - CH2: 0, -90°, +90°, 180° between the output voltages of Channel 1 and 2. The test results presented in Figs. 7 and 8 show that the relative short-term phase stability is equal to 4 mrad for the WW2572A and 6 mrad for the AP SYS-2722. Total Harmonic Distortion factors of the sinewaves generated by the examined sources were also checked. THD on the level of -100 dB proves very high signal purity. The results of the relative amplitude and phase stability measurements prove that it is possible to obtain the uncertainty of impedance comparison on 10-5 level using the WW2572A or AP SYS-2722 generator in the comparator bridge shown in Fig.

Digitally controlled switch for realization of inductance unit at the Central Office of Measures (GUM, Warsaw)

W artykule przedstawiono koncepcję modernizacji stanowisk do realizacji jednostki Henra w Państwowych Instytucjach Metrologicz-nych. Opisano stanowisko do odtwarzania jednostki w Głównym Urzędzie Miar w Warszawie i - za zgodą GUM - zamieszczono wyniki badań zmodernizowanego stanowiska wyposażonego w multiplekser wzorców indukcyjności własnej. Stabilne i zgodne z otrzymanymi przed modyfikacją wyniki badań zmodernizowanego stanowiska w Głównym Urzędzie Miar świadczą o możliwości zastąpienia przełącznika mechanicznego MCS1 multiplekserem DCS2 przy zachowaniu dobrej powtarzalności i dokładności wyników komparacji.A concept of modernization of stations for realization of inductance unit at National Metrology Institutes is presented in the paper. The concept is based on appliance a new digitally controlled switch for comparison of inductance standards. A station at the Central Office of Measures (GUM) in Warsaw is described. The national primary inductance standard at the GUM consists of four GR1482H inductors (Tab. 1) kept in the thermostat (Fig. 1). The old station at the GUM (Fig. 2) was modernized by the applying the digitally controlled switch DCS2 (Fig. 3) in 2007 [7, 8, 9]. Then the comparison measurements at the old and the new stations were performed to confirm accuracy and usefulness of the new digitally controlled switch. Results of delta L measurements for national inductance standards at the GUM before and after the modernization are presented in Tab 2. In Tab. 3 the corrected results of deltas taking into account reversion of standards are presented. Very stable (and similar to the results achieved at the old station) results of measurements prove that the old mechanical switch can be replaced by the new digitally controlled one. The new digitally controlled switch connected with the modern comparator bridge enables automation of the comparison process and gives a new possibilities of investigation of the measuring current, time and temperature on the comparison results

Fluctuations of the effective value of a sinusoidal signal, generated by sources using direct digital synthesis (DDS)

W pracy dokonano analizy zjawiska fluktuacji wartości skutecznej sygnału cyfrowego, generowanego przez cyfrowe źródła wzorco-wego napięcia przemiennego, wykorzystujące metodę bezpośredniej cyfrowej syntezy sygnału (DDS). Podano wzory umożliwiające wyznaczenie najbardziej i najmniej korzystnych, z punktu widzenia fluktuacji wartości skutecznej, nastaw inkrementu fazy układu DDS. Wzory te umożliwiają zdeterminowanie zakresu przestrajania układu DDS, dla którego wartość międzyszczytowa fluktuacji wartości skutecznej jest mniejsza od założonej wartości.The paper analyzes the phenomenon of fluctuations of effective value of the signal generated by the digital source of standard AC voltage. The source is based on the method of direct digital signal synthesis (DDS) with phase accumulation. Almost all of up to now published papers, dealing with properties of the signal generated by DDS sources, concentrate on spectral purity of the signal and methods of reduction of its unwanted spectral components (spurs). This paper focuses on effective value of the signal generated by the direct digital synthesizer. Authors wanted to check whether it was possible to use DDS in an AC standard voltage source generating a sinusoidal signal with very stable and accurate RMS value. Given are equations for easily setting the most and least favorable phase incre-ments of DDS in terms of fluctuations in the effective value. These equations allow determination of the setting range of the phase increment of the DDS, for which the peak-to-peak fluctuations of the effective value are lower than assumed