Publications Repository - Gdańsk University of Technology

Buckling of thin-walled columns accounting for initial geometrical imperfections

• Czesław Szymczak
• Marcin Kujawa

2017 INTERNATIONAL JOURNAL OF NON-LINEAR MECHANICS

The paper is devoted to the effect of some geometrical imperfections on the critical buckling load of axially compressed thin-walled I-columns. The analytical formulas for the critical torsional and flexural buckling loads accounting for the initial curvature of the column axis or the twist angle respectively are derived. The classical assumptions of theory of thin-walled beams with non-deformable cross-sections are adopted. The non-linear differential equations are derived and the critical buckling loads are approximated by means of the Galerkin’s method. Comparison of analytical results to numerical analysis of simply supported I-columns by means of finite element method (FEM) is provided. Moreover the analytical formulas is adapted to I-columns with lipped flanges and satisfactory agreement of analytical and numerical results of stability analysis is observed.

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Building Dedicated Project Management Process Basing on Historical Experience

• Miłosz Kurzawski
• Cezary Orłowski
• Artur Ziółkowski
• Tomasz Deręgowski

2017 Full text

Project Management Process used to manage IT project could be a key aspect of project success. Existing knowledge does not provide a method, which enables IT Organizations to choose Project Management methodology and processes, which would be adjusted to their unique needs. As a result, IT Organization use processes which are not tailored to their specific and do not meet their basic needs. This paper is an attempt to fill this gap. It describes a method for selecting management methodologies, processes and engineering practices most adequate to project characteristic. Choices are made on the basis of organization’s historical experience. Bespoken Project Management process covers technical and non-technical aspects of software development and is adjusted to unique project challenges and needs. Created process is a hybrid based on CMMI for Development Model, it derives from different sources, uses elements of waterfall and Agile approaches, different engineering practices and process improvement methods.

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Building Information Modelling as an opportunity and risk for stakeholders involved in construction investment process

• Beata Grzyl
• Emilia Miszewska
• Magdalena Apollo

2017 Full text Procedia Engineering

The requirements to apply Building Information Modelling (BIM) in public investments worldwide are currently very high. Significant interest (sometimes formulated also as a requirement) in BIM technology can be observed also among private investors. Design technology that applies BIM is supported by many private investors due to its numerous advantages. A growing group of construction designers (steel, concrete and reinforced concrete among others) and installation designers, producers of prefabricated elements (steel and reinforcements), engineers, architects, construction companies, developers, contract managers and investors in Poland and worldwide notices opportunities offered by using BIM technology in preparation and construction phase, as well as building management. At the same time experts in construction industry draw attention to the low level of competitiveness of Polish construction companies in global and European market caused, among others, by insufficient application of modern technology and innovation, as well as lack of public investor’s initiative in promoting the application of BIM. It is difficult to assess the level of BIM implementation in Polish companies (due to lack of wider research results). The goal of this paper is to present the results of initial research regarding the level of knowledge of BIM and the scope of its implementation in Polish construction companies. The goal of the research was also to establish the level of interest and ability to implement BIM by public investors, architecture and construction companies. The paper also presents the scope of actions undertaken by the state, in the context of public investments using BIM.

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Building Knowledge for the Purpose of Lip Speech Identification

• Andrzej Czyżewski
• Bożena Kostek
• Marcin Szykulski
• Tomasz Ciszewski

2017 Advances in Intelligent Systems and Computing

Consecutive stages of building knowledge for automatic lip speech identification are shown in this study. The main objective is to prepare audio-visual material for phonetic analysis and transcription. First, approximately 260 sentences of natural English were prepared taking into account the frequencies of occurrence of all English phonemes. Five native speakers from different countries read the selected sentences in front of three cameras. Video signals, synchronized with audio, were registered and then analyzed. Encountered problems related to video registration and results achieved are discussed.

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Bus bays inventory using a terrestrial laser scanning system

• Katarzyna Bobkowska
• Jakub Szulwic
• Paweł Tysiąc

2017 Full text MATEC Web of Conferences

This article presents the use of laser scanning technology for the assessment of bus bay geo-location. Ground laser scanning is an effective tool for collecting three-dimensional data. Moreover, the analysis of a point cloud dataset can be a source of a lot of information. The authors have outlined an innovative use of data collection and analysis using the TLS regarding information on the flatness of bus bays. The results were finalized in the form of colour three-dimensional maps of deviations and pavement type. Bus bays inventory using a terrestrial laser scanning system. Available from: https://www.researchgate.net/publication/319051349_Bus_bays_inventory_using_a_terrestrial_laser_scanning_system [accessed Sep 27, 2017].

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Business angels jako alternatywne źródło finansowania start-upów

• Gabriela Golawska-Witkowska
• Ewa Mazurek-Krasodomska
• Anna Rzeczycka

2017

Podmioty gospodarcze jako element każdego modelu gospodarki są bardzo istotne z punktu widzenia funkcjonowania każdego systemu ekonomicznego na świecie. Stan gospodarki jest bowiem silnie zależny od dynamicznego rozwoju sektora przedsiębiorczości. Zależność ta zachodzi na wszystkich etapach rozwoju gospodarczego, może ona jednak przybierać różne nasilenie i charakter. W Polsce, podobnie jak na całym świecie, powstaje wiele nowych przedsiębiorstw. Główną barierą ich rozwoju w początkowej fazie jest niewątpliwie brak kapitału. Wdrożenie i realizacja obiecujących pomysłów jest bardzo często niemożliwa z powodu braku funduszy. Dlatego też celem niniejszego artykułu jest ocena roli aniołów biznesu w finansowaniu przedsiębiorstw w zalążkowej lub początkowej fazie rozwoju. Aniołowie biznesu pełnią bardzo ważną rolę na rynku kapitału ryzyka. Aktywnie oddziałują na zmniejszenie luki kapitałowej występującej w potrzebach start-upów. Zapewniają dostęp do kapitału nowym, innowacyjnym firmom, bez którego nie mogłyby funkcjonować i rozwijać się. Business angels stanowią więc kluczowy element rozwoju przedsiębiorstw, stymulując rozwój sektora małych i średnich firm Dlatego należy tworzyć zachęty fiskalne dla potencjalnych inwestorów i zwiększyć poziom wiedzy z zakresu finansów i przedsiębiorczości. Przełoży się to na wzrost realizowanych przez anioły biznesu inwestycji i znaczny wzrost innowacyjności polskiej gospodarki.

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Bydgoska retencja +2050

• Ziemowit Suligowski

2017 Inżynieria Morska i Geotechnika

Program retencji bydgoskiej dla perspektywy 2050. Główne założenia programu. Wnioski wynikające z przeprowadzonej dyskusji.

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C-1311 (Symadex), a potential anti-cancer drug, intercalates into DNA between A and G moieties. NMR-derived and MD-refined stereostructure of the d(GAGGCCTC) 2 :C-1311 complex

• Tomasz Laskowski
• Julia Borzyszkowska-Bukowska
• Jakub Grynda
• Jan Mazerski

2017 JOURNAL OF MOLECULAR STRUCTURE

Imidazoacridinone C-1311 (Symadex®) is an antitumor agent which has been recommended for Phase II clinical trials a few years ago. Previously, it was shown experimentally that during the initial stage of its action C-1311 forms stable intercalation complexes with DNA duplexes. Herein, a NMR-derived stereostructure of d(GAGGCCTC)2:C-1311 complex was reported. The ligand was found locating itself between A and G moieties, forming symmetrical DNA:drug 1:2 mol/mol complex. Intercalation site was located upon the DNA-ligand proton/proton dipolar couplings observed in the NOESY spectrum and the performed MD simulations. NMR-derived stereostructure was hence refined by restrained MD using distance restraints obtained from the NOESY data and the result was compared with MD-derived structure of the proposed complex, obtained from the calculations performed with distance restraints applied only for hydrogen bonds in the terminal GC base pairs. The results of both simulations were coherent. Basing on the observed C-1311's intercalation sites and on our previous results concerning the d(CGATCG)2:C-1311 complex, we stated that AG/GA sequences are the preferred binding sites of imidazoacridinone C-1311.

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Calculation method for flow boiling and flow condensation of R134a and R1234yf in conventional and small diameter channels

• Dariusz Mikielewicz
• Blanka Jakubowska

2017 Full text Polish Maritime Research

The paper presents the results of calculations performed using the authors’ model to predict the heat transfer coefficient during flow boiling for two refrigerants R134a and R1234yf. The experimental data from various past studies have been collected and the calculations have been conducted for the full range of quality variation and a wide range of mass velocity. The aim of the study was to test the sensitivity of the in-house flow boiling and flow condensation model. The importance of taking into account the surface tension as the parameter exhibiting its importance in case of the flow in minichannels, as well as the influence of the reduced pressure were analysed. The obtained numerical results show good consistency with those recorded in the experiments.

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Cancer-selective, single agent chemoradiosensitising gold nanoparticles

• Sophie Grellet
• Konstantina Tzelepi
• Meike Roskamp
• Phil Williams
• Aquila Sharif
• Richard Slade-Carter
• Peter Goldie
• Nicky Whilde
• Małgorzata Śmiałek-Telega
• Nigel J. Mason
• Jon Golding

2017 Full text PLOS ONE

Two nanometre gold nanoparticles (AuNPs), bearing sugar moieties and/or thiol-polyethylene glycol-amine (PEG-amine), were synthesised and evaluated for their in vitro toxicity and ability to radiosensitise cells with 220 kV and 6 MV X-rays, using four cell lines representing normal and cancerous skin and breast tissues. Acute 3 h exposure of cells to AuNPs, bearing PEG-amine only or a 50:50 ratio of alpha-galactose derivative and PEG-amine resulted in selective uptake and toxicity towards cancer cells at unprecedentedly low nanomolar concentrations. Chemotoxicity was prevented by co-administration of N-acetyl cysteine antioxidant, or partially prevented by the caspase inhibitor Z-VAD-FMK. In addition to their intrinsic cancer-selective chemotoxicity, these AuNPs acted as radiosensitisers in combination with 220 kV or 6 MV X-rays. The ability of AuNPs bearing simple ligands to act as cancer-selective chemoradiosensitisers at low concentrations is a novel discovery that holds great promise in developing low-cost cancer nanotherapeutics.

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Canonical switched capacitor converters. Comments, complements, and refinements

• Marek Makowski
• Alexander Kushnerov

2017

Switched Capacitor Converters (SCC) form useful blocks in low/medium power applications as they are suitable for integration, both as off-chip and on-chip IC realizations. However, the problem with SCC is that their voltage conversion ratio is topology-dependent. By changing the SC circuit configuration, we can gain control over voltage conversion but the available ratio remains of a discrete nature, i.e. it maps into a countable set of target voltages. Recent papers, on two-phase and multi-phase converters have attempted to solve the so-called canonical circuit realization problem. A converter circuit is canonical in the sense that it can realize all theoretically attainable ratios, the said realizations are not necessarily unique, it contains the minimum number of circuit elements needed for such a circuit, and it takes the form of expandable modular blocks. We briefly review reported SCC topologies with large numbers of ratios and critically filter out and assess the candidates for canonicity. We focus on two illustrative examples based on our previous research. Finally, we comment on open questions and theoretical peculiarities found.

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Capacitively coupled ECG measurements - a CMRR circuit improvement

• Adam Bujnowski
• Mariusz Kaczmarek
• Kamil Osiński
• Marta Gońka
• Jerzy Wtorek

2017

A typical galvanic-connected electrocardiogram (ECG) measurement system utilizes two signal’s electrodes and a third one in driven-right-leg (DRL) circuit for improving a common-mode rejection ratio(CMRR) of the acquisition system. In capacitive-coupled ECG similar techniques are used, however it is expected, that the utilized DRL subsystem is formed using a capacitive coupling approach, too. An improvement of the acquisition system performance by improving DRL circuit is presented in the paper.

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Capillary pumped loop as a tool for collecting large heat fluxes from electronic devices on warships

• Dariusz Mikielewicz
• Paweł Szymański

2017 Full text Polish Maritime Research

The combat potential of future warships will be directly related to the use of modern electronic devices being parts of advanced systems, such as, for instance, radar systems, fire aiming systems, fire detection systems, electric drive systems, and even electronic and radio-electronic weaponry, railguns and lasers, installed on these warships. The capacity and functionality of these devices is continually increasing, at decreasing mass and dimensions, which results in higher power consumption. Heat collection becomes a growing problem in operation of these devices. The paper presents a concept of the use of the CPL (Capillary Pumped Loop) cycle for passive heat collection from precise electronic devices used on warships. It also includes the description of the experimental rig and discussion of the results of laboratory tests performed on this rig and confirmed using the mathematical model developed by the authors.

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Carbon nanowalls: A new versatile graphene based interface for laser desorption/ionization-mass spectrometry detection of small compounds in real samples.

• Ioana Hosu
• Michał Sobaszek
• Mateusz Ficek
• Robert Bogdanowicz
• Hervé Drobecq
• Luc Boussekey
• Alexandre Barras
• Oleg Melnyk
• Rabah Boukherroub
• Yannick Coffinier

2017 NANOSCALE

Carbon nanowalls, vertically aligned graphene nanosheets, attract attention owing to their tunable band-gap, high conductivity, high mechanical robustness, high optical absorbance and other remarkable properties. In this paper, we report for the first time, the use of hydrophobic boron-doped carbon nanowalls (CNWs) for laser desorption/ionization of small compounds and their subsequent detection by mass spectrometry (LDI-MS). The proposed method offers sensitive detection of various small molecules in absence of organic matrix. The CNWs were grown by microwave plasma enhanced chemical vapor deposition (MW-PECVD), using a boron-carbon gas flow ratio of 1200 in H2/CH4 plasma, on silicon <100> wafer. The hydrophobicity of the surface offers a straightforward MS sample deposition, consisting in drop casting solutions of analytes and drying in air. Limit of detections in the picomolar and femtomolar range (25 fmol/µl for neurotensin) were achieved for different types of compounds (fatty acids, lipids, metabolites, saccharides and peptides) having clinical or food industry interests. This rapid and sensitive procedure can also be used for quantitative measurements without internal standards with RSDs <19%, as in the case of glucose in either aqueous solutions (LOD=0.32±0.02 pmol), blood serum or soft drinks, as well. Moreover, melamine (63±8.19 ng/µL), a toxic compound, together with creatinine and paracetamol, were detected in urine samples, while lecithin was detect in food supplements.

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Carboxy derivative of dioxydiphenylpropane diglycydyl ether monomethacrylate as an addtive for composites

• Michael Bratychak
• Oksana Latsyshyn
• Olena Shyshchak
• Atsakhova Olena
• Helena Janik

2017 Full text Chemistry & Chemical Technology

The modifier of composites was used in the presence of polyetylene polyamine. Physico-mechanical properties and chemical stability of coatings thus obtained were analyzed.

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Carotid Artery Stenting and Blood–Brain Barrier Permeability in Subjects with Chronic Carotid Artery Stenosis

• Arkadiusz Szarmach
• Grzegorz Halena
• Mariusz Franciszek Kaszubowski
• Maciej Piskunowicz
• Michal Studniarek
• Piotr Lass
• Edyta Szurowska
• Pawel Winklewski

2017 Full text INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES

Failure of the blood-brain barrier (BBB) is a critical event in the development and progression of diseases such as acute ischemic stroke, chronic ischemia or small vessels disease that affect the central nervous system. It is not known whether BBB breakdown in subjects with chronic carotid artery stenosis can be restrained with postoperative recovery of cerebral perfusion. The aim of the study was to assess the short-term effect of internal carotid artery stenting on basic perfusion parameters and permeability surface area-product (PS) in such a population. Forty subjects (23 males) with stenosis of >70% within a single internal carotid artery and neurological symptoms who underwent a carotid artery stenting procedure were investigated. Differences in the following computed tomography perfusion (CTP) parameters were compared before and after surgery: global cerebral blood flow (CBF), cerebral blood volume (CBV), mean transit time (MTT), time to peak (TTP) and PS. PS acquired by CTP is used to measure the permeability of the BBB to contrast material. In all baseline cases, the CBF and CBV values were low, while MTT and TTP were high on both the ipsi- and contralateral sides compared to reference values. PS was approximately twice the normal value. CBF was higher (+6.14%), while MTT was lower (−9.34%) on the contralateral than on the ipsilateral side. All perfusion parameters improved after stenting on both the ipsilateral (CBF +22.66%; CBV +18.98%; MTT −16.09%, TTP −7.62%) and contralateral (CBF +22.27%, CBV +19.72%, MTT −14.65%, TTP −7.46%) sides. PS decreased by almost half: ipsilateral −48.11%, contralateral −45.19%. The decline in BBB permeability was symmetrical on the ipsi- and contralateral sides to the stenosis. Augmented BBB permeability can be controlled by surgical intervention in humans.

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Cast iron in the 19th-century building equipment

• Michał Kwasek
• Aleksander Piwek

2017 Full text IOP Conference Series: Materials Science and Engineering

Cast iron is a material, characteristics of which enable to receive extremely artistic elements. It maintains good strength properties at the same time. That combination of these seemingly contrary traits makes it a commodity that was widely used in the 19th century industry and architecture. These usages were not only as decorative elements, technical and structural ones. The production of new household utilities started, which made people’s lives more comfortable. Cast iron allowed for fast and cheap production while maintaining high aesthetic qualities. Useful elements, which often were ornamental parts of buildings were created. The aim of the article is to characterise elements of interior equipment of the 19th century building that are made of cast iron. As it appears from performed bibliography, archival and field studies, the ways of exploitation are very broad. Some were mounted into the building; the others were a mobile equipment. As it occurred they were most commonly used as functional items. Cast iron was used to produce the minor elements, which were only parts of the bigger wooden or stone items. Notwithstanding, there were also bigger ones casted as a whole, and frequently ones that were assembled from many elements. Nowadays, elements of an interior feature are one of the subjects of study during the restoration work of the buildings. They can provide important information about the building and the way people lived and are considered as the essential part of historical objects.

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Cast polyurethanes obtained from reactive recovered polyol intermediates via crude glycerine decomposition process

• Patrycja Jutrzenka Trzebiatowska
• Ilona Deuter
• Janusz Datta

2017 Full text REACTIVE & FUNCTIONAL POLYMERS

In this work, the possibility of applying intermediates from polyurethane waste recycling in polyurethane synthesis was presented. Polyurethanes were synthesised in a two-step method using a mixture of petrochemical polyol and glycerolysate, used as a reactive component, 4,4-diphenylmethane diisocyanate (MDI) and 1,4-buthanediol (BD). Glycerolysates were produced during decomposition of polyurethane elastomer by crude glycerine from biodiesel production. The glycerolysates were incorporated into polyurethane structure and co-created a soft segment with their functional groups. Chemical structure and properties of the cast polyurethanes were characterised by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA) and mechanical tests. Results showed that higher incorporation of glycerolysates shifts the glass transition to higher temperatures and the mechanical properties indicates that material exhibits more stiff structure. Prepared polyurethanes which contained glycerolysates have good and similar (in a small amount of glycerolysate) properties to the reference polyurethane which indicates the possibility of glycerolysate application as a polyol in the polyurethane synthesis.

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Castelo Branco Cityscapes

• Jacek Krenz

2017

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Catalytic impact of alloyed Al on the corrosion behavior of Co50Ni23Ga26Al1.0 magnetic shape memory alloy and catalysis applications for efficient electrochemical H2 generation

• Amin Mohammed
• Nader El-bagoury
• Mohamed Mahmoud
• Mahmoud Hessien
• Sayed El-rehim
• Joanna Wysocka
• Jacek Ryl

2017 Full text RSC Advances

The electrochemical and corrosion behaviour of Co50Ni23Ga27-xAlx (x = 0 and 1.0 wt%) magnetic shape memory alloys (MSMAs) was studied in 0.5 M NaCl solutions using various electrochemical techniques. Results showed remarkable activation of the tested MSMA toward pitting corrosion upon alloying it with Al. XPS examination confirmed the activation influence of alloyed Al. It proved that the presence of Al in the alloy's matrix weakens its passivity, as manifested by lower amount of gallium oxides and Cl- adsorption in aluminium containing MSMA sample. Alloyed Al also activated significantly the tested MSMA for the hydrogen evolution reaction (HER), as indicated by cathodic polarization, electrochemical impedance spectroscopy (EIS), and Faradaic efficiency (FE) measurements. Such measurements were performed in 0.1 M KOH solutions and showed that Co50Ni23Ga26Al1.0 alloy is much more active for the HER than Co, Ni, Co50Ni50, and Co50Ni23Ga27 electrodes. The catalytic impact of pitting corrosion, proved to be catalyzed by Al, on the HER activity of CoNiGaAl alloy was also studied. The pitted Co50Ni23Ga26Al1.0 MSMA, the best catalyst here, exhibited high HER catalytic performance with an exchange current density (jo) of 0.2 mA cm-2 and FE 96%, thus approached Pt/C (jo = 0.6 mA cm-2 and FE ~ 100%). Our best catalyst also showed good stability and durability after 3000 cycles of cathodic polarization between the corrosion potential (Ecorr) and -1.0 V vs. RHE, and 24h of electrolysis at a high cathodic current density of 100 mA cm-2. Microstructure changes made by Al, together with findings obtained from SEM/EDX mapping and XPS studies, were used to interpret its activation influence towards the HER

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