Filters
total: 1822
filtered: 1564
-
Catalog
Chosen catalog filters
displaying 1000 best results Help
Search results for: FINANCIAL INSTABILITY
-
A literature survey of the influence of preform reheating and stretch blow moulding with hot mould process parameters on the properties of PET containers – part 2.
PublicationThe hot fill process is an inexpensive conventional filling technology for high-acidity products (pH < 4.5). It allows certain drinks (sensitive beverages such as fruit and vegetable juices, nectars, soft drinks, vitaminised water) to be stored at ambient temperature without the need for chemical preservatives. The primary feature of the bottles used in the hot fill process is their temperature stability, i.e. the ability to retain...
-
A literature survey of the influence of preform reheating and stretch blow molding with hot mold process parameters on the properties of PET containers. Part I.
PublicationThe hot fill process is an inexpensive conventional filling technology for high-acidity products (pH < 4.5). It allows certain drinks (sensitive beverages such as fruit and vegetable juices, nectars, soft drinks, vitaminized water) to be stored at ambient temperature without the need for chemical preservatives. The primary feature of the bottles used in the hot fill process is their temperature stability, i.e. the ability to retain...
-
Production of new non-matrix reference material of ethene
PublicationThe main objective of the research is to produce new non-matrix reference materials of ethene. The study are based on thermal decomposition of surface compound chemically bonded with the surface of glass fibers coated with thin layer of aluminum. Positivehomogeneity test, stability test and organization of inter-laboratory comparison are leading to find new non-matrix reference materials which are indispensable tools in the analysis...
-
Enzyme immobilization on magnetic nanoparticles
PublicationImmobilized enzymes have been commonly used in many branches of industry, biotechnology, medicine and also in analytical chemistry. Their use provides many advantages in comparison with free enzymes including repeated, easy recovery of the enzyme and improvement in enzyme stability. Enzymes are strong and specific catalysts, but are also expensive and fragile. Their immobilization and stabilization may reduce reaction costs, which...
-
Distortional buckling of thin-walled columns of closed quadratic cross-section
PublicationThe elastic stability of axially compressed column related to the cross-section distortion is investigated. Two kinds of closed quadratic cross-sections are taken into consideration with internal walls and without it. The governing differential equation is derived with aid of the principle of stationary total potential energy. The critical loads for the simply supported columns are found in an analytical form and compared with...
-
Detailed investigation of the phase transition inKxP4W8O32and experimental arguments for a charge density wave due to hidden nesting
PublicationDetailed structural and magnetotransport properties of monophosphate tungsten bronze Kx(PO2)4(WO3)8 single crystals are reported. Both galvanomagnetic and thermal properties are shown to be consistent with a charge density wave electronic transition due to hidden nesting of the quasi-1D portion of the Fermi surface. We also observe the enhancement of electronic anisotropy due to reconstruction of the Fermi surface at the Peierls...
-
Construction of glucosamine-6-phosphate synthase with an internal hexahistydyl fragment
PublicationL-Glutamine: D-fructose-6-phosphate aminotransferase (EC 2.6.1.16), known also as glucosamine-6-phosphate (GlcN-6-P) syntase, catalyzes the first committed step in the amino sugar biosynthetic pathway in prokaryotic and eukaryotic organisms. The enzyme carries out a complex reaction involving ammonia transfer and sugar phosphate isomerization. GlcN-6-P syntase is an important point of metabolic control of amino sugar biosynthesis...
-
On mixing in the class of quadratic stochastic operators
PublicationWe study different types of limit behavior of quadratic stochastic operators acting on ℓ^1 (or ℓ^1_d) spaces in both strong and uniform topologies. The main motif of the paper is to express the uniform and strong asymptotic stability of the quadratic stochastic operator in terms of convergence of the associated (linear) nonhomogeneous Markov chain. We also examine which type of uniform convergence of iterates of the quadratic...
-
Influence of the shoe type on the ground reaction forces
PublicationThe aim of this work was to estimate a relationship between the type of the footwear and ground reactions. Differences in medio-lateral, anterior-posterior and vertical reactions are compared for different shoe-types for male and female volunteers. Each of the participants gait was recorded in case of different shoes and without them, also stabilograms were analyzed. Results revealed differences in ground reaction forces for different...
-
REALIZACJA USŁUGI DSR NA PRZYKŁADZIE DOMÓW JEDNORODZINNYCH
PublicationW artykule przedstawiono ideę usługi DSR, czyli reakcji strony popytowej, dla odbiorców rozproszonych. Polega ona na zmniejszeniu zapotrzebowania na energię elektryczną lub przesunięcia go w czasie. Wdrożenie usługi może w znaczny sposób wpłynąć na pracę systemu elektroenergetycznego – usługa DSR może wspomóc bilansowanie systemu elektroenergetycznego, a także pozytywnie oddziaływać na jego elastyczność, wydajność oraz stabilność....
-
Extraction and evaluation of gas-flow-dependent features from dynamic measurements of gas sensors array
PublicationGas analyzers based on gas sensors are the devices which enable recognition of various kinds of volatile compounds. They have continuously been developed and investigated for over three decades, however there are still limitations which slow down the implementation of those devices in many applications. For example, the main drawbacks are the lack of selectivity, sensitivity...
-
Giant Reed (Arundo donax L.) Fiber Extraction and Characterization for Its Use in Polymer Composites
PublicationThis work describes an extraction method for giant reed fibers from stems and leaves based on chemical soaking and crushing through a rolling mill. Obtained fibers, together with the shredded plant (stems + leaves), are characterized in terms of chemical composition, thermal stability, morphology, and crystallinity. Mechanical properties of fibers have also been assessed (single fiber tensile tests). The results show that the proposed...
-
Ship weather routing optimization with dynamic constraints based on reliable synchronous roll prediction
PublicationShip routing process taking into account weather conditions is a constrained multi-objective optimization problem and it should consider various optimization criteria and constraints. Formulation of a stability-related, dynamic route optimization constraint is presented in this paper. One of the key objectives of a cross ocean sailing is finding a compromise between ship safety and economics of operation. This compromise should...
-
Ternary Bismuthide SrPtBi2: Computation and Experiment in Synergism to Explore Solid-State Materials
PublicationA combination of theoretical calculation and the experimental synthesis to explore the new ternary compound is demonstrated in the Sr–Pt–Bi system. Because Pt–Bi is considered as a new critical charge-transfer pair for superconductivity, it inspired us to investigate the Sr–Pt–Bi system. With a thorough calculation of all the known stable/metastable compounds in the Sr–Pt–Bi system and crystal structure predictions, the thermodynamic...
-
A framework for onboard assessment and monitoring of flooding risk due to open watertight doors for passenger ships
PublicationPost-accident safety of ships is governed by damage stability, affected by watertight subdivisions which limit accidental flooding. This is important for passenger ships with watertight doors (WTDs) often fitted in the bulkheads. Awareness of the ship flooding risk due to open WTDs and the conditions under which the associated risk level changes are prerequisites for proactive risk mitigation. Accident risk is often expressed as...
-
Thermal buckling of functionally graded piezomagnetic micro- and nanobeams presenting the flexomagnetic effect
PublicationGalerkin weighted residual method (GWRM) is applied and implemented to address the axial stability and bifurcation point of a functionally graded piezomagnetic structure containing flexomagneticity in a thermal environment. The continuum specimen involves an exponential mass distributed in a heterogeneous media with a constant square cross section. The physical neutral plane is investigated to postulate functionally graded material...
-
Historical crane on the redesigned original trestle bridge as a memorial of Gdansk Shipyard
PublicationThe paper includes selected aspects of the study, whose goal is to hold the historical crane 642-24 in its current location after the modification of trestle bridge static scheme. The scope of the paper includes the assessment of current technical condition of the object, a presentation of FEM analyses, a description of the assumed load cases, results of the static calculations, checking the effort of construction elements, global...
-
Nowe substancje psychoaktywne CZ. II. SYNTETYCZNE KANNABINOIDY - CHARAKTERYSTYKA, METODY OZNACZANIA I WYZWANIA ANALITYCZNE
PublicationDo nielegalnego obrotu co roku trafiają nowe związki o działaniu psychoaktywnym. Dostęp do takich substancji nie jest trudny, gdyż są one łatwo dostępne w wielu krajach, głównie w sklepach internetowych. Ponadto, organy ścigania i wymiar sprawiedliwości nie nadążają z wprowadzaniem tych substancji na listy substancji zakazanych przez co ich kontrola jest bardzo utrudniona. Syntetyczne kannabinoidy to grupa związków chemicznych,...
-
Rigid polyurethane foams with different flame retardants and their physical and mechanical properties
PublicationRigid polyurethane foams (PUFs) containing 3, 6 or 9 % of one of of two selected fire retardants (FR): oligomeric ethyl ethylene phosphate (Fyrol PNX) and expandable graphite (EG) were prepared, inspected and compared to foam without that fillers as the control. The thermal stability of PUFs was described by horizontal test according to norm: UL 94 HB. Compressive strength and physical properties (density, fragility and water absorption)...
-
Dynamics of a simplified HPT model in relation to 24h TSH profiles
PublicationWe propose a simplified mathematical model of the hypothalamus-pituitary-thyroid (HPT) axis in an endocrine system. The considered model is a modification of the model proposed by Mukhopadhyay and Bhattacharyya in [10]. Our system of delay differential equations reconstructs the HPT axis in relation to 24h profiles of human in physiological conditions. Homeostatic control of the thyroid-pituitary axis is considered by using...
-
State Observer for Doubly-fed Induction Generator
PublicationIn the paper a new state observer for doubly-fed generator has been proposed. In the new approach an extended mathematical model of the doubly fed generator is used to form equations of the introduced z type observer. Stability of the observer has been verified through poles placement analyses. The active and reactive powers of the generator are controlled by a nonlinear multiscalar control method. Simulation and experimental results...
-
DiSTFAG method robust to gross errors in monitoring displacements and strains in unstable reference systems
PublicationThe DiSTFA method (Displacements and Strains using Transformation and Free Adjustment) was presented in Kamiński (2009). The method has been developed for the determination of displacements and strains of engineering objects in unstable reference systems, as well as for examining the stability of reference points. The DiSTFAG (Gross errors) method presented in the paper is the extension of the DiSTFA method making it robust to...
-
Wpływ imperfekcji geometrycznych na bezpieczeństwo montażu i naprawy zbiorników cylindrycznych metoda podbudowy
PublicationW pracy zajęto się wyznaczeniem nośności granicznej zbiorników stalowych o osi pionowej montowanych lub naprawianych z zastosowaniem hydraulicznego systemu podnoszenia konstrukcji. Podniesiony zbiornik jest szczególnie narażony na utratę stateczności, a obciążenie wiatrem utrudnia prowadzenie prac. Jakiekolwiek deformacje blach, szczególnie w pobliżu zamocowań podnośników mogą w znacznym stopniu obniżyć obciążenie krytyczne konstrukcji....
-
The Business Environment of Georgia and Ukraine: Approaches to a Comparative Analysis
PublicationThe formation of a favourable business environment and the intensification of entrepreneurial activity on this basis is one of the priorities of economic policy of governments around the world. The aim of this article is to conduct a comparative analysis of some of the characteristics of the business environment of Georgia and Ukraine. The theoretical basis of the study is the understanding of the business environment as a necessary...
-
Effects of La0.8Sr0.2MnO3 and Ag electrodes on bismuth-oxide-based low-temperature solid electrolyte oxygen generators
PublicationIn this study, La0.8Sr0.2MnO3 (LSM) was used as the ceramic electrode in a (Bi1.50Y0.50)0.98Zr0.04O3+δ (BYO)-based solid electrolyte oxygen generator (SEOG) and its performance was compared with that of a previously studied high-fire Ag electrode. Among La0.6Sr0.4Co0.2Fe0.8O3, LaNi0.6Fe0.4O3, Cu1.4Mn1.6O4, and LSM materials, only LSM materials did not trigger any chemical reaction or interdiffusion with BYO at temperatures up to...
-
Self-organized multilayered graphene-boron doped diamond hybrid nanowalls for high performance electron emission devices
PublicationCarbon nanomaterials like nanotubes, nanoflakes/nanowalls and graphene have been used as electron sources due to their superior field electron emission (FEE) characteristics. Nevertheless, these materials show poor stability and a short lifetime, preventing them from being used in practical device applications. The intention of this study was to find an innovative nanomaterial, possessing both high robustness and reliable FEE behavior....
-
Impact of diffusion coefficient averaging on solution accuracy of the 2D nonlinear diffusive wave equation for floodplain inundation
PublicationIn the study, the averaging technique of diffusion coefficients in the two-dimensional nonlinear diffusive wave equation applied to the floodplain inundation is presented. As a method of solution, the splitting technique and the modified finite element method with linear shape functions are used. On the stage of spatial integration, it is often assumed that diffusion coefficient is constant over element and equal to its average...
-
The influence of the welding environment on the properties of Tekken joints made from S355J2C+N steel
PublicationThere are three main methods of underwater welding: dry, wet and intermediate between them, by using the local dry chamber. Due to low costs, the most common method is the wet welding with the use of covered electrodes. Water as a welding environment carries out a lot of problems. The first is limited visibility and instability of the welding arc. The biggest problem during underwater welding is high susceptibility to cold cracking,...
-
Viability of fruit seed oil O/W emulsions in personal care products
PublicationThe use of fruit seed oils in personal care products is of significance to both their function and image. Poland is an important processor of fruit products within the EU, and thus has a large availability of seeds from domestic fruits, which are normally considered to be a waste material or feed for livestock. Unfortunately, current literature is scarce of the suitability of these oils for topical dermatological use in the form...
-
Hyaluronan-Chondroitin Sulfate Anomalous Crosslinking Due to Temperature Changes
PublicationGlycosaminoglycans are a wide class of biopolymers showing great lubricating properties due to their structure and high affinity to water. Two of them, hyaluronic acid and chondroitin sulfate, play an important role in articular cartilage lubrication. In this work, we present results of the all-atom molecular dynamics simulations of both molecules placed in water-based solution. To mimic changes of the physiological conditions,...
-
Application of soil nailing technique for protection and preservation historical buildings
PublicationSoil nailing is one of the recent in situ techniques used for soil improvement and in stabilizing slopes. The process of soil nailing consists of reinforcing the natural ground with relatively small steel bars or metal rods, grouted in the pre-drilled holes. This method has a wide range of applications for stabilizing deep excavations and steep slopes. Soil nailing has recently become a very common method of slope stabilisation...
-
Influence of silver-core gold-shell nanoparticle parameters on the variation of surface-enhanced Raman spectra
PublicationThe detection of molecules by surface-enhanced Raman spectroscopy (SERS) is dependent on the nanomaterial used to induce the enhancement effect. This depends on a variety of parameters of the substrate such as the metal used for their creation, their shape, size and size distribution, concentration, as well as the parameters of the solution, such as packing of the nanoparticles, the complexity of the sample, the solvent, etc. It...
-
Investigation of Thermoplastic Polyurethanes Synthesized via Two Different Prepolymers
PublicationThe man aim of this work was to investigate the effect of the molecular weight of polyols, mixture of prepolymers, and [NCO]/[OH] molar ratio used during the prepolymer chain extending step on the chemical structure, thermomechanical and mechanical properties, and thermal stability of thermoplastic poly(ether-urethane)s In this work thermoplastic poly(ether-urethane)s were synthesized by using polyols with a various molecular weight,...
-
Enzymatic and Chemical Cross-Linking of Bacterial Cellulose/Fish Collagen Composites—A Comparative Study
PublicationThis article compares the properties of bacterial cellulose/fish collagen composites (BC/Col) after enzymatic and chemical cross-linking. In our methodology, two transglutaminases are used for enzymatic cross-linking—one recommended for the meat and the other proposed for the fish industry—and pre-oxidated BC (oxBC) is used for chemical cross-linking. The structure of the obtained composites is characterized by scanning electron...
-
COMPUTER-AIDED DESIGN OF ORGANOPHOSPHORUS INHIBITORS OF UREASE
PublicationBased on the structure of the most potential inhibitor diamidophosphate, various novel groups of inhibitors were developed by knowledge-based design approach with covalent carbon-phosphorus or carbon-phosphorus-carbon bond to improve hydrolytic stability to inhibit the microbial ureases. Designed compounds were evaluated with 10 (LigScore1, LigScore2, PLP1, PLP2, JAIN, PMF, PMF04, LUDI_1, LUDI_2 and LUDI_3) different scoring functions...
-
Theoretical study of thermofrictional oscillations due to negative friction-temperature characteristic
PublicationAnalytical study on oscillations of a body on a moving counterbody has been done by assuming imperfect frictional thermal contact and friction that decreases with contact temperature. It has been shown that stick-slip oscillation occurs due to decrease of friction coefficient when the body moves in the opposite direction to the counterbody. Dynamical characteristics, such as conditions for stable sliding and limit cycles, have...
-
Osoby starsze wobec innowacyjnych form świadczenia usług ubezpieczeniowych
PublicationPrzedmiotem zainteresowania badawczego w niniejszym tekście są usługi ubezpieczeniowe świadczone z wykorzystaniem innowacyjnych środków komunikacji: Internetu lub telefonu. W artykule skoncentrowano się na osobach powyżej 50 roku życia, szczególnie narażonych na zjawisko wykluczenia cyfrowego. Na podstawie przeglądu literatury sformułowano hipotezę badawczą: Cechy społeczno – demograficzne osób powyżej 50 roku życia wpływają na ich...
-
Chemorezystancyjny czujnik gazu na bazie polimeru przewodzącego PEDOT
PublicationPolimery przewodzące, takie jak Poli(3,4-etylenodioksytiofen) (PEDOT) są atrakcyjnymi materiałami elektrodowymi, które posiadają takie zalety, jak biokompatybilność, duża przewodność i elastyczność. Elektroprzewodzące polimery można otrzymać w wyniku chemicznej polimeryzacji lub elektropolimeryzacji. W niniejszej pracy przedstawiono zostanie koncepcja czujnika gazów składająca się z elektrody grzebieniowej oraz polimeru przewodzącego...
-
Termooksydacyjna i fotooksydacyjna degradacja pianek poliuretanowych
PublicationPrzeprowadzono ocenę efektywności działania wybranych środków przeciwstarzeniowych w sztywnych piankach poliuretanowych, otrzymywanych na drodze syntezy jednoetapowej. Ocenę tę oparto na pomia-rach zmian barwy oraz wytrzymałości mechanicznej zsyntezowanych materiałów. Na podstawie analizy uzyskanych wyników stwierdzono, iż dodatek 3% mieszaniny I rzędowego antyutleniacza fenolowego oraz benzotriazolowego absorbera UV znacząco zmniejsza...
-
Weighted difference schemes for systems of quasilinear first order partial functional differential equations
PublicationThe paper deals with initial boundary value problems of the Dirichlet type for system of quasilinear functional differential equations. We investigate weighted difference methods for these problems. A complete convergence analysis of the considered difference methods is given. Nonlinear estimates of the Perron type with respect to functional variables for given functions are assumed. The proof of the stability of difference problems...
-
Computer-aided analysis of resonance risk in power system with Static Var Compensators
PublicationStatic Var Compensators operation in a power system may significantly improve voltage profiles in nodes and the reactive power balance, as well as ensure greater system stability in emergency conditions. However these devices may be a cause of a resonance in the system. The aim of this paper is to call attention to the need to include resonance phenomena in a compensator’s location evaluation process. The analysis performed in...
-
Solid Oxide Fuel Cells with Ni infiltrated perovskite anode
PublicationNiobium-doped strontium titanate was used as the anode for a solid oxide fuel cell. Electrolyte-supported cells were prepared with pure perovskite and composite perovskite–yttria–stabilized-zirconia (YSZ) anodes. Fuel cell tests demonstrated significant improvement in power density after infiltration with a small amount of Ni. The obtained values of power densities are comparable with conventional Ni/YSZ cermet anode. In addition,...
-
Synthesis and Testing of BCZY/LNZ Mixed Proton–electron Conducting Composites for Fuel Cell Applications
PublicationA composite of BaCe0.6Zr0.2Y0.2O3–δ and Li2O:NiO:ZnO was investigated for fuel cell applications. The composite was successfully synthesized and its phase stability was confirmed at temperatures up to 900 °C. The influence of sintering and pressing aids on density was also investigated. Electrical properties were measured. DC electrical conductivity was about 8•10-4 S/m at 845 K. Open circuit voltage measurements in wet hydrogen...
-
Reduction of Computational Complexity in Simulations of the Flow Process in Transmission Pipelines
PublicationThe paper addresses the problem of computational efficiency of the pipe-flow model used in leak detection and identification systems. Analysis of the model brings attention to its specific structure, where all matrices are sparse. With certain rearrangements, the model can be reduced to a set of equations with tridiagonal matrices. Such equations can be solved using the Thomas algorithm. This method provides almost the same values...
-
ECONOMICAL AND SAFE METHOD OF GRANULAR MATERIAL STORAGE IN SILOS IN OFFSHORE PORT TERMINALS
PublicationThe article discusses issues related with storage of granular materials in silos made of corrugated sheets and reinforced with vertical ribs. Advantages and disadvantages of these structures are named, and typical technological solutions used by largest silo producers are presented. Moreover, basic assumptions of Eurocode 3 are discussed in the context of determining the buckling load capacity of a ribbed jacket. Alternative methods...
-
Analysis of a gene expression model
PublicationWe study a mathematical model of gene transcription and protein synthesis with negative feedback. We consider a system of equations taking into account the number of active binding sites, the way in which dimers bind to DNA and time delay in translation process. For a simplified model that consist of three ordinary differential equations with time delay we derive conditions for stability of the positive steady state and for the...
-
Sensorless Rotor Position Estimation of Doubly-Fed Induction Generator Based on Backstepping Technique
PublicationThis paper proposes a speed observer algorithm for the sensorless control of a doubly-fed induction generator based on classical adaptive backstepping technique. The sensorless control is shown using classic stator field oriented control which is used to active and reactive power control. Performance of the proposed algorithm of a speed observer is validated by simulation and experimental results obtained using a small-rating generator...
-
Participatory Budgeting in Poland – Missing Link in Urban Regeneration Process
PublicationIn last thirty years Poland has gone a long way toward democracy and decentralization. Role of public participation in planning is increasing rapidly and recently many new instruments of empowering the community is being introduced, participatory budgeting is one of the most important. On the other hand, urban regeneration is one of the most important challenges of polish cities are facing. Technical and transport infrastructure...
-
Protection and viability of fruit seeds oils by nanostructured lipid carrier (NLC) nanosuspensions
PublicationIn this paper, we focused on the development of nanostructured lipid carriers (NLCs) for dermal application. The NLC matrix was designed as a protective reservoir of biological active compounds that naturally occur in domestic fruit seed oils. Over the years, emulsions, as a popular physicochemical form of personal care products, were refined in order to obtain the best possible penetration into the skin of any bioactive compound...
-
The Effect of Cobalt Incorporation into Nickel–Iron Oxide/(oxy)hydroxide Catalyst on Electrocatalytic Performance Toward Oxygen Evolution Reaction
PublicationThis work presents a study on the influence of the addition of cobalt into state-of-the-art nickel–iron (NiFe) mixed oxides/hydroxides/(oxy)hydroxides on their structural and morphological properties, and oxygen evolution reaction (OER) catalytic activity. A one-step electrodeposition process is performed without any additives to fabricate NiFe and x cobalt-doped nickel/iron (xCoNiFe) layer-double-hydroxide catalysts directly on...