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Search results for: minimum sample size
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Investigation of Wood Flour Size, Aspect Ratios, and Injection Molding Temperature on Mechanical Properties of Wood Flour/Polyethylene Composites
PublicationIn the present research, wood flour reinforced polyethylene polymer composites with a coupling agent were prepared by injection molding. The effects of wood flour size, aspect ratios, and mold injection temperature on the composites’ mechanical properties were investigated. For the preparation of the polymer composites, five different formulations were created. The mechanical properties including tensile strength and the modulus,...
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The size of enterprises in which graduates of the Gdańsk University of Technology work – years 2010-2018
Open Research DataThe dataset includes data from the survey on the Gdańsk University of Technology graduates from years 2010-2018 on the size of enterprises in which they work. The survey was conducted in the period from 2012 to 2020, two years after the respondents obtained graduate status. The research sample included 12776 respondents. To summarize, the Gdańsk University...
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Size effect in concrete beams under bending – influence of the boundary layer and the numerical description of cracks
PublicationIn the paper the size effect phenomenon in concrete is analysed. The results of numerical simulations of using FEM on geometrically similar un-notched and notched concrete beams under bending are presented. Concrete beams of four different sizes and five different notch heights under three-point bending test were simulated. In total 18 beams were analysed. Two approaches were used to describe cracks in concrete. First, eXtended...
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Dagmara Nikulin dr
PeopleBio: Dagmara Nikulin Dagmara Nikulin has been employed at the Faculty of Management and Economics as a research and teaching assistant professor since 2014. Initially, she worked at the Department of Economic Sciences, and now at the Department of Statistics and Econometrics. She is a graduate of the Faculty of Economics at the Poznań University of Economics (2009) and the Faculty of Social Sciences of the Adam Mickiewicz University...
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Explicit Size-Reduction-Oriented Design of a Compact Microstrip Rat-Race Coupler Using Surrogate-Based Optimization Methods
PublicationIn this paper, an explicit size reduction of a compact rat-race coupler implemented in a microstrip technology is considered. The coupler circuit features a simple topology with a densely arranged layout that exploits a combination of high- and low-impedance transmission line sections. All relevant dimensions of the structure are simultaneously optimized in order to explicitly reduce the coupler size while maintaining equal power...
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Wojciech Wojnowski dr inż.
PeopleUkończył V Liceum Ogólnokształcące w Gdańsku w klasie o profilu matematyczno-fizycznym z wykładowym językiem angielskim. W 2009 roku rozpoczął studia na Wydziale Chemicznym PG na kierunku technologia chemiczna, uzyskując w 2012 roku tytuł inżyniera, a w 2013 tytuł magistra. W latach 2013–2015 studiował sinologię na Uniwersytecie w Nankinie dzięki uzyskaniu Stypendium Rządu ChRL. Po powrocie do Polski w 2015 roku rozpoczął studia...
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Sample processing for DNA chip array-based analysis of enterohemorrhagic Escherichia coli (EHEC)
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Relationships between biomarkers of inflammation, ovarian steroids, and age at menarche in a rural polish sample
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A Robust Method for Sample Preparation of Gastrointestinal Stromal Tumour for LC/MS Untargeted Metabolomics
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Sample Concentration of Charged Small Molecules and Peptides in Capillary Electrophoresis by Micelle to Cyclodextrin Stacking
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Evaluation of occupational exposure in a slide bearings factory on the basis of urine and blood sample analyses
PublicationZbadano wpływ pracy w zakładach łożysk ślizgowych na zdrowie pracowników. Przeprowadzono analizę próbek moczu i krwi pobranych od 42 pracowników i 6 osób zatrudnionych w administracji przedsiębiorstwa, stanowiących grupę kontrolną. Oznaczono zawartość Al, Cu, Pb i Zn we krwi i moczu pracowników dwukrotnie, przed i po terapii za pomocą chelatowania, stosując ICP-MS oraz metodę dodatku wzorca. Istotność różnic w zawartości pierwiastków...
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Patch size setup and performance/cost trade-offs in multi-objective antenna optimization using domain patching technique
PublicationA numerical study concerning multi-objective optimization of antenna structures using sequential domain patching (SDP) technique has been presented. We investigate the effect of various setups of the patch size on the operation of the SDP algorithm and possible trade-offs concerning the quality of the Pareto set found by SDP and the computational cost of the optimization process. Our considerations are illustrated using a UWB monopole...
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Long-Term Impact of Wind Erosion on the Particle Size Distribution of Soils in the Eastern Part of the European Union
PublicationWind erosion is the leading cause of soil degradation and air pollution in many regionsof the world. As wind erosion is controlled by climatic factors, research on this phenomenon isurgently needed in soil and land management in order to better adapt to climate change. In thispaper, the impact of wind erosion on the soil surface in relation to particle size distribution wasinvestigated. Changes in percentage of sand, silt and...
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Particle size distribution (laser granulometry) of pristine bismuth oxide (Bi2O3) and gadolinium oxide (Gd2O3) structures
Open Research DataData contain raw results of particle size distribution (by volume) of Bi2O3 and Gd2O3 particles determined using a laser diffraction method (Malvern Mastersizer 2000, Worcestershire, UK).
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On Decision-Making Strategies for Improved-Reliability Size Reduction of Microwave Passives: Intermittent Correction of Equality Constraints and Adaptive Handling of Inequality Constraints
PublicationDesign optimization of passive microwave components is an intricate process, especially if the primary objective is a reduction of the physical size of the structure. The latter has become an important design consideration for a growing number of modern applications (mobile communications, wearable/implantable devices, internet of things), where miniaturization is imperative due to a limited space allocated for the electronic circuitry....
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PSYCHOMETRIC PROPERTIES OF THE POLISH VERSION OF THE GENERALIZED ANXIETY DISORDER 7-ITEM SCALE (GAD-7) IN A NON-CLINICAL SAMPLE OF EMPLOYEES DURING PANDEMIC CRISIS
PublicationObjectives: The COVID-19 outbreak is an example of a crisis that triggered an increase in generalized anxiety disorder. The study aims to validate the Polish version of the Generalized Anxiety Disorder 7-item scale (GAD-7) by Spitzer et al. among a non-clinical sample of employees and examine the invariance depending on the gender and age of working adults. Material and Methods: For assessing factor structure of the Polish version...
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Inverse modeling for fast design optimization of small-size rat-race couplers incorporating compact cells
PublicationIn the paper, a framework for computationally-efficient design optimization of compact rat-race couplers (RRCs) is discussed. A class of hybrid RRCs with variable operating conditions is investigated, whose size reduction is obtained by replacing ordinary transmission lines with compact microstrip resonant cells (CMRCs). Our approach employs a bottom-up design strategy leading to the development of compact RRCs through rapid design...
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The Influence of the Application of EP Additive in the Minimum Quantity Cooling Lubrication Method on the Tool Wear and Surface Roughness in the Process of Turning 316L Steel
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Body size and wing asymmetry in bees along an urbanization gradient
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IFF/SSR rectangular patch antenna with reduced transversal size
PublicationW artykule przedstawiono antenę mikropaskową dla systemów IFF/SSR, zasilaną poprzez szczelinę typu H. Zastosowanie tego typu szczeliny pozwoliło na 36-procentową redukcję wymiaru poprzcznego anteny,co jest szczególnie istotne ze względu na potencjalne zastosowanie anteny w szykach.Pomierzone parametry eektryczne anteny to: VSWR < 1.5; stosunek polaryzacji ortogonalnej do właściwej < 30 dB w obu płaszczyznach;zysk > 7 dBi.
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Feature type and size selection for adaboost face detection algorithm
PublicationThe article presents different sets of Haar-like features defined for adaptive boosting (AdaBoost) algorithm for face detection. Apart from a simple set of pixel intensity differences between horizontally or vertically neighboring rectangles, the features based on rotated rectangles are considered. Additional parameter that limits the area on which the features are calculated is also introduced. The experiments carried out on...
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Specific cutting resistance while sawing of wood - the size effect
PublicationW artykule przedstawiono wyniki analiz zmian właściwego oporu skrawania, przy zastosowaniu współczesnej mechaniki pękania z uwzględnieniem wiązkości. Analizy wykonano dla procesu przecinania drewna na pilarce ramowej PRW15M drewna jesionu i jesionu modyfikowanego termicznie. Zastosowane podejście pozwala na wyjaśnienie zjawiska wzrostu właściwego powierzchniowego oporu skrawania dla niewielkich grubości warstwy skrawanej jako efektu...
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Tighter bounds on the size of a maximum P3-matching in a cubic graph
PublicationW pracy pokazano, że największe P3-skojarzenie dla dowolnego grafu o n>16 wierzchołkach składa się z przynajmniej 117n/152 wierzchołków.
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Applications of compression techniques for reducing the size of multibeam sonar records
PublicationJednym z najczęściej używanych urządzeń służących do szeroko rozumianego telemonitoringu morskiego są sonary wielowiązkowe (ang. Multibeam systems - MBS). Ich wysoka wydajność w tworzeniu informacji o obiektach znajdujących się pod wodą skutkuje w dużych ilościach danych pozyskiwanych podczas rejsów badawczych i pomiarowych. W tym kontekście, proces przechowywania i zarządzania takim magazynem danych staje się istotnym problemem...
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Potential of Mean Force of Hydrophobic Association: Dependence on Solute Size
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The estimation of norwegian cod size distribution from acoustic data
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Analysis of size and shape of abrasive micrograins in lapping of assembly joints
PublicationPrzedstawiono skomputeryzowana analizę wielkości i kształtu mikroziaren ściernych. W badaniach mikroziaren węglika boru, węglika krzemu i elektrokorundu zastosowano mikroskopie optyczna oraz specjalistyczne oprogramowanie MultiScan v.6.08
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FE-simulations of size effects in granular and quasi-brittle materials
PublicationW artykule przedstawiono symulacje efektów skali w materiałach granulowanych i kruchych. Obliczenia wykonano dla ściskania dwuosiowego i fundamentu w przypadku materiałów granulowanych oraz belek zginanych w przypadku materiałów kruchych. Do obliczeń wykorzystano mikropolarne prawo hipoplastyczne i sprężysto-plastyczne prawo z nielokalnym osłabieniem.
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Deterministic and statistical size effect during shearing of granular layer
PublicationArtykuł omawia deterministyczny i statystyczny efekt skali w materiałach granulowanych podczas ścinania cienkiej warstwy piasku między dwoma bardzo szorstkimi ścianami. Obliczenia wykonano metodą elementów skończonych na bazie mikropolarnego prawa hipoplastycznego. Pokazano wyniki efektu skali przy zastosowaniu różnych metod redukujących ilość realizacji pól losowych dla początkowego wskaźnika porowatości..
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Effect of particle size of aluminosilicate microspheres on the change of hydration heat of cement mortars and selected physical, chemical, and mechanical properties.
Open Research DataThis subject of the work is the study of selected properties of cement mortars containing two fractions of aluminosilicate microspheres with grain size in the range of 125 to 250 μm and from 250 to 500 μm. Mortar mixtures with ordinary Portland cement (OPC 42.5R) and three substitution rates of cement by microspheres, 1.5%, 3.5%, and 5.0%, were investigated....
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Bee Bread Exhibits Higher Antimicrobial Potential Compared to Bee Pollen
PublicationThis study aimed at investigation of the antimicrobial potential of ethanolic extracts of bee bread (BB) and bee pollen (BP) and suspensions of these products in MHB (Mueller Hinton Broth). We covered 30 samples of BP and 19 samples of BB harvested in Polish apiaries. Slightly lower activity was observed against Gram-negative bacteria compared to Gram-positive staphylococci. BB extracts exhibited higher inhibitory potential with...
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INNOWACYJNA METODA WZMOCNIENIA PRZYCZÓŁKA WIADUKTU PRZY UŻYCIU INIEKCJI GEOPOLIMEROWYCH
PublicationW obecnych czasach szybki rozwój infrastruktury i nowoczesnych technologii niejednokrotnie narzuca projektantom oraz wykonawcom takie rozwiązania, aby prowadzone roboty budowlane, były jak najmniej uciążliwe dla uczestników ruchu i jak najmniej ingerowały w system komunikacyjny. Dotyczy to zarówno budowy nowych obiektów jaki i remontu obiektów już istniejących. W niniejszej pracy przedstawiono nowatorską koncepcję remontu wiaduktu...
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Corrosion Resistance and Surface Bioactivity of Ti6Al4V Alloy after Finish Turning under Ecological Cutting Conditions
PublicationThe influence of cooling conditions and surface topography after finish turning of Ti6Al4V titanium alloy on corrosion resistance and surface bioactivity was analyzed. The samples were machined under dry and minimum quantity lubrication (MQL) conditions to obtain different surface roughness. The surface topographies of the processed samples were assessed and measured using an optical profilometer. The produced samples were subjected...
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Study on Dry Sliding Wear and Friction Behaviour of Al7068/Si3N4/BN Hybrid Composites
PublicationHybrid aluminium metal matrix composites have the potential to replace single reinforced aluminium metal matrix composites due to improved properties. Moreover, tribological performance is critical for these composites, as they have extensive application areas, such as the automotive, aerospace, marine and defence industries. The present work aims to establish the tribological characteristics of Al7068/Si3N4/BN hybrid metal matrix...
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Study of Non-Newtonian biomagnetic blood flow in a stenosed bifurcated artery having elastic walls
PublicationFluid structure interaction (FSI) gained attention of researchers and scientist due to its applications in science felds like biomedical engineering, mechanical engineering etc. One of the major application in FSI is to study elastic wall behavior of stenotic arteries. In this paper we discussed an incompressible Non-Newtonian blood fow analysis in an elastic bifurcated artery. A magnetic feld is applied along x direction. For...
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Performance and Emission Modelling and Simulation of Marine Diesel Engines using Publicly Available Engine Data
PublicationTo analyse the behaviour of marine diesel engines in unsteady states for different purposes, for example to determine the fuel consumption or emissions level, to adjust the control strategy, to manage the maintenance, etc., a goal-based mathematical model that can be easily implemented for simulation is necessary. Such a model usually requires a wide range of operating data, measured on a test stand. This is a time-consuming process...
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Shaking table experimental study on pounding between adjacent structures founded on different soil types
PublicationThe aim of this study is to extensively investigate the effect of the soil type on the response of colliding structures based on shaking table experimental tests. Two single-storey models of steel buildings with different dynamic parameters were considered in this study. Three pounding scenarios were taken into account by applying different seismic gaps (0.5 cm, 1 cm and 1.5 cm as well as the no pounding case). First, the effect...
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Understanding the Electronic Structure and Optical Properties of Vacancy-Ordered Double Perovskite A2BX6 for Optoelectronic Applications
PublicationOver the past few years, metal halide perovskite solar cells have made significant advances. Currently, the single-junction perovskite solar cells reach a conversion efficiency of 25.7%. Perovskite solar cells with a wide band gap can also be used as top absorber layers in multi-junction tandem solar cells. We examined the dynamical and thermal stability, electronic structure, and optical features of In2PtX 6 (X = Cl, Br, and I)...
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The atlas of inequality aversion: theory and empirical evidence on 55 countries from the Luxembourg Income Study database
PublicationResearch background: In the distributive analysis, the constant relative inequality aversion utility function is a standard tool for ethical judgements of income distributions. The sole parameter ε of this function expresses a society’s aversion to inequality. However, the profession has not committed to the range of ε. When assessing inequality and other welfare characteristics, analysts assume an arbitrary level of ε, common...
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Bi-GRU-APSO: Bi-Directional Gated Recurrent Unit with Adaptive Particle Swarm Optimization Algorithm for Sales Forecasting in Multi-Channel Retail
PublicationIn the present scenario, retail sales forecasting has a great significance in E-commerce companies. The precise retail sales forecasting enhances the business decision making, storage management, and product sales. Inaccurate retail sales forecasting can decrease customer satisfaction, inventory shortages, product backlog, and unsatisfied customer demands. In order to obtain a better retail sales forecasting, deep learning models...
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Cost-Efficient EM-Driven Size Reduction of Antenna Structures by Multi-Fidelity Simulation Models
PublicationDesign of antenna systems for emerging application areas such as the Internet of Things (IoT), fifth generation wireless communications (5G), or remote sensing, is a challenging endeavor. In addition to meeting stringent performance specifications concerning electrical and field properties, the structure has to maintain small physical dimensions. The latter normally requires searching for trade-off solutions because miniaturization...
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Seeking genetic signature of radiosensitivity - a novel method for data analysis in case of small sample sizes
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Monitoring of volatile organic compounds (VOCs) in atmospheric air. Part II. Sample collection and preparation
PublicationThe paper reviews literature information on air sampling techniques commonly used for monitoring volatile organic compounds (VOCs) levels in atmospheric air. It describes containers for collecting samples of atmospheric air, such as vacuum canisters and bags made from synthetic materials. It discusses dynamic, passive and denudational techniques for sampling analytes from air combining isolation with preliminary enrichment, and...
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Self-adjusting sub-sample delay estimator based on fractional delaying Hilbert transform filter
PublicationZaprezentowano nowe rozwiązanie samo-nastrajalnego estymatora opóźnienia sygnału sinusoidalnego, działającego w czasie dyskretnym. Zastosowano filtr Hilberta o skończonej odpowiedzi ipulsowej (FIR od ang. finite impulse response) zagregowany z filtrem ułamkowo-opóźniającym. Zilustrowano performancję estymatora, również w obecności szumu. Przeanalizowano jego złożoność numeryczną.
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Sample preparation for gas chromatographic determination of halogenated volatile organic compounds in environmental and biological samples
PublicationPodstawowym elementem przygotowania próbek środowiskowych i biologicznych do analizy jest etap izolacji i/lub wzbogacania polegający na przeniesieniu analitów z matrycy pierwotnej charakteryzującej się złożonym i często zmiennym składem (próbka oryginalna) do matrycy wtórnej z równoczesnym usunięciem substancji przeszkadzających (izolacja)i zwiększeniem stężenia analitów do poziomu powyżej granicy oznaczalności stosowanego przyrządu...
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Evaluation of sample injection precision in respect to sensitivity in capillary electrophoresis using various injection modes
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The Indirect Relationship Between Spiritual Experiences and Subjective Wellbeing Through Hope? A Sample of Chilean Students
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Determination of environmental pollutants in soil and sediments - some aspects of sample clean-up and GC analysis
PublicationPrzedstawiono wstępne wyniki badań nowej procedury analitycznej przeznaczonej do badań próbek i osadów dennych na zawartość związków organicznych (WWAPCB). Procedura składa się z następujących etapów: - ekstrakcji analitów z wykorzystaniem techniki ASE, - oczyszczania ekstraktów (kolumienki), - chromatograficznego rozdzielania i oznaczania analitów.
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Mechanical Properties, Microstructure and Surface Quality of Polypropylene Green Composites as a Function of Sunflower Husk Waste Filler Particle Size and Content
PublicationAgricultural waste is a still untapped source of materials that can, in case of proper utilization, significantly improve the sustainability of polymers and their composites. In this work, polymer composites based on isotactic polypropylene were produced incorporating ground sunflower husk in the amount of 10 wt% and 20 wt%. The work’s main objective is to evaluate how preliminary fractioning of this agricultural waste filler affects...
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Size and mass minimization of capacitor bank in a power converter DC line of DC drive with closed loop control system with PWM and current limitation
PublicationPaper deals with evaluation equations for power filter of AC-DC power converter which allows to provide size and mass minimization of capacitor bank in DC drive closed loop systems with PWM and current limitation. Reliability of provided equations is proved by simulation in MATLAB/Simulink