bluuebunny/crossref_metadata_2025 huggingface dataset:
Advanced oxidation technologies for the treatment and detoxification of olive mill wastewater: a general review
Authors: Elkacmi Reda , Bennajah Mounir
Published: October 2019

Olive oil production has an economic importance for Mediterranean countries, ensuring employment opportunities and export earnings. The crushing units produce two types of residues, one solid (pomace) and the other liquid, called olive mill wastewater (OMW). This by-product has adverse effects on the olive oil sector and particularly on the quality of waters into which they are discharged. Hence, there is a critical need to orient the scientific research toward the treatment of this hazardous waste. Several techniques have been proposed and developed for OMW management. However, the advanced oxidation processes (AOP) remain the most advantageous with high treatment efficiencies. This trend allowed achieving a significant detoxification of OMW. A considerable amount of effort has been expanded to provide detailed and critical reviews on the use of this alternative technology in the treatment of water and wastewaters. Regrettably most, if not all, of these review papers were not focused mainly on OMW application. This paper aims to highlight the ancient and recent progress of various types of oxidation techniques for OMW treatment. Moreover, principles, advantages, limitations, and efficiencies of each method are presented, to gain a more scientific understanding of the most feasible approach regarding the treatment of this harmful residue.
An Overview on Pyranocoumarins: Synthesis and Biological Activities
Authors: Vlachou Evangelia-Eirini N. , Litinas Konstantinos E.
Published: October 2019

Pyrano- and dipyranocoumarins are classes of naturally occurring organic compounds with very interesting biological activities. This review focuses on the synthetic strategies for the synthesis of pyranocoumarins and dipyranocoumarins and the biological properties of those compounds. The synthesis involves the formation of the pyran ring, at first, from a coumarin or the formation of pyranone moiety from an existing pyran. Pyranocoumarins and dipyranocoumarins present anti-HIV, anti-cancer, neuroprotective, antidiabetic, antibacterial, antifungal, anti-inflammatory activities. Especially khellactones and calanolides are usually potent and selective in anti-HIV activity. Decursin and decursinol derivatives are effective as anticancer, neuroprotective, antidiabetic, antibacterial, and antifungal agents.
Understanding the Mechanism of Cell Death in Gemcitabine Resistant Pancreatic Ductal Adenocarcinoma: A Systems Biology Approach
Authors: Aier Imlimaong , Varadwaj Pritish K.
Published: October 2019

Background:

Gemcitabine is the standard chemotherapeutic drug administered in advanced
Pancreatic Ductal Adenocarcinoma (PDAC). However, due to drug resistance in PDAC patients, this
treatment has become less effective. Over the years, clinical trials for the quest of finding novel compounds
that can be used in combination with gemcitabine have met very little success.

Objective:

To predict the driving factors behind pancreatic ductal adenocarcinoma, and to understand
the effect of these components in the progression of the disease and their contribution to cell growth
and proliferation.

Methods:

With the help of systems biology approaches and using gene expression data, which is generally
found in abundance, dysregulated elements in key signalling pathways were predicted. Prominent
dysregulated elements were integrated into a model to simulate and study the effect of gemcitabine-
induced hypoxia.

Results:

In this study, several transcription factors in the form of key drivers of cancer-related genes
were predicted with the help of CARNIVAL, and the effect of gemcitabine-induced hypoxia on the
apoptosis pathway was shown to have an effect on the downstream elements of two primary pathway
models; EGF/VEGF and TNF signalling pathway.

Conclusion:

It was observed that EGF/VEGF signalling pathway played a major role in inducing drug
resistance through cell growth, proliferation, and avoiding cell death. Targeting the major upstream
components of this pathway could potentially lead to successful treatment.
Human Microbiome and Allergic Diseases in Children: Pathogenetic Role and Therapeutic Options
Authors: Musso Paola , Chiappini Elena , Bernardini Roberto
Published: October 2019

:

The recent and extensive study of the microbiome has provided an enormous amount of
data concerning the type and possible functions of microorganisms present in the gut, airways, genital
tract, and skin. These data showed interpersonal differences in the composition of the microbiome
and these differences suggest a link between the microbiome, the immune modulation, and the
pathogenesis of allergic diseases.

:

This research is particularly relevant in paediatrics, since allergic diseases are constantly increasing
and there is evidence in the paediatric age that shows that the composition of the microbiome in the
foetal and neonatal period plays a key role in the development of the immune system: vaginal delivery,
breastfeeding, childhood spent in rural environments and/or in contact with animals result in
a greater biodiversity of the microbiome with the presence of protective species that reduce the activation
of Th2 lymphocytes, involved in allergic reactions.

:

Further studies are necessary to better understand the microbiota role in the pathogenesis of atopy
in order to understand if specific probiotics and prebiotics, administered orally or topically, can affect
the microbiota composition and modulate immune system functions, producing a therapeutic
effect in the treatment of allergic diseases.

:

This narrative review analysed the available literature regarding the correlation between the microbiome
and the development of allergic diseases and with special focus on paediatric studies. The
skin, gut or lung dysbiosis can be a cofactor in the pathogenesis of allergies and the remodulation
of the microbiome becomes an important therapeutic challenge.
A Review of Analytical Methods for the Determination of Tibolone: Pharmacokinetics and Pharmaceutical Formulations Analysis and Application in Doping Control
Authors: Ângelo Marilene Lopes , de Lima Moreira Fernanda , Araújo Santos Ana Laura , Nunes Salgado Hérida Regina , de Araújo Magali Benjamim
Published: October 2019

Background::

Tibolone is a synthetic steroid commercialized by Organon under the brand
name Livial (Org OD14), which is used in hormone therapy for menopause management and treatment
of postmenopausal osteoporosis. Tibolone is defined as a selective tissue estrogenic activity regulator
(STEAR) demonstrating tissue-specific effects on several organs such as brain, breast, urogenital tract,
endometrium, bone and cardiovascular system.

Aims::

This work aims to (1) present an overview of important published literature on existing methods
for the analysis of tibolone and/or its metabolites in pharmaceutical formulations and biological fluids
and (2) to conduct a critical comparison of the analytical methods used in doping control, pharmacokinetics
and pharmaceutical formulations analysis of tibolone and its metabolites.

Results and conclusions: :

The major analytical method described for the analysis of tibolone in pharmaceutical
formulations is High Pressure Liquid Chromatography (HPLC) coupled with ultraviolet
(UV) detection, while Liquid Chromatography (LC) or Gas Chromatography (GC) used in combination
with Mass Spectrometry (MS) or tandem mass spectrometry (MS/MS) is employed for the analysis of
tibolone and/or its metabolites in biological fluids.
A Metaheuristic Based Approach for Threshold Optimization for Spectrum Sensing in Cognitive Radio Networks
Authors: Mahendru Garima , Shukla Anil K. , Patnaik Lalit M.
Published: October 2019

Background:

The mounting growth of wireless technology is attracting a high demand
for the frequency spectrum. The measurements of spectrum usage depict that a significant portion
of the spectrum lays unoccupied or overcrowded. The main cause of the glitch is the existing inefficient
and fixed scheme of spectral allocation. Cognitive radio is one such technology that permits
wireless devices to detect the unused frequency band and reconfigure its operating parameters to attain
the required quality of service.

Objective:

To permit the dynamic allocation of the frequency band, spectrum sensing is performed
which is an essential function of Cognitive radio and involves detection of an unused spectrum space
to set up a communication link.

Method:

This paper presents a meta-heuristic approach for selection of a decision threshold for energy
detection based spectrum sensing. At low SNR and in the presence of noise uncertainty, the
performance of energy detection method fails. A novel adaptive double threshold based spectrumsensing
method is proposed to avoid such a sensing failure. Further, the metaheuristic approach employs
Particle Swarm Optimization (PSO) algorithm to compute an optimal value of the threshold to
attain robustness against noise uncertainty at low SNR.

Results:

The simulation results of the proposed metaheuristic double threshold based spectrum sensing
method demonstrate enhanced performance in comparison to the existing methods in terms of
reduced error rate and increased detection probability. Some of the existing methods have been analyzed
and compared from a survey of recent patents on spectrum sensing methods to support the new
findings The concept of adaptive thresholding improves the detection probability by 39 % and 27
% at noise uncertainty of 1.02 and 1.04, respectively at a signal to noise ratio of -10 dB. Furthermore,
the error probability reduces to 58% at the optimal threshold using Particle Swarm Optimization
(PSO) algorithm for the signal to noise ratio of -9 dB.

Conclusions:

The main outcome of this work is the reduction in the probability of sensing failure
and improvement in the detection probability using adaptive double thresholds at low SNR. Further,
particle swarm optimization helps in obtaining the minimum probability of error under noise uncertainty
with an optimal threshold.
Vasorelaxant Effect of Novel Nitric Oxide-Hydrogen Sulfide Donor Chalcone in Isolated Rat Aorta: Involvement of cGMP Mediated sGC and Potassium Channel Activation
Authors: Sherikar Amol , Dhavale Rakesh , Bhatia Manish
Published: October 2019

Background and Objective: :

Recently, nitric oxide (NO) and hydrogen sulfide (H2S)
donating moieties were extensively studied for their role in the vasculature as they are responsible for
many cellular and pathophysiological functioning. The objective of the present study is to evaluate
novel NO and H2S donating chalcone moieties on isolated rat aorta for vasorelaxation, and to
investigate the probable mechanism of action.

Methods::

To extend our knowledge of vasorelaxation by NO and H2S donor drugs, here we
investigated the vasorelaxing activity of novel NO and H2S donating chalcone moieties on isolated rat
aorta. The mechanism of vasorelaxation by these molecules was investigated by performing in vitro
cGMP mediated sGC activation assay and using Tetraethylammonium chloride (TEA) as a potassium
channel blocker and Methylene blue as NO blocker.

Results::

Both NO and H2S donating chalcone moieties were found to be potent vasorelaxant. The
compound G4 and G5 produce the highest vasorelaxation with 3.716 and 3.789 M of pEC50,
respectively. After the addition of TEA, G4 and G5 showed 2.772 and 2.796 M of pEC50, respectively.
The compounds Ca1, Ca2, and D7 produced significant activation and release of cGMP mediated sGC
which was 1.677, 1.769 and 1.768 M of pEC50, respectively.

Conclusion: :

The vasorelaxation by NO-donating chalcones was blocked by Methylene blue but it did
not show any effect on H2S donating chalcones. The vasorelaxing potency of NO-donating molecules
was observed to be less affected by the addition of TEA but H2S donors showed a decrease in both
efficacy and potency. The cGMP release was more in the case of NO-donating molecules. The tested
compounds were found potent for relaxing vasculature of rat aorta.
A DPOC na Área Metropolitana do Porto e o efeito das ondas de calor e de frio na enfermidade
Authors: Silveira Rafael Brito , Alves Maikon Passos Amilton , Sousa Carlos Miguel , Gonçalves Paula , Monteiro de Sousa Ana Maria Rodrigues , Franke Alberto Elvino
Published: October 2019

Caracterizou-se a doença pulmonar obstrutiva crónica (DPOC) e os possíveis aspectos socioeconómicos associados à enfermidade e avaliaram-se os efeitos que as ondas de calor (OdC) e as ondas de frio (OdF) podem ter no aumento dos internamentos hospitalares nas pessoas residentes na Área Metropolitana do Porto (AMP) entre 2000 e 2015. Os efeitos das OdC e das OdF nas admissões hospitalares por DPOC foram investigados por meio da análise de regressão linear múltipla, com nível de significância de α = 5%. A análise estatística e cartográfica da distribuição geográfica dos internamentos hospitalares por DPOC, por grupos etários, por taxa de analfabetismo e por taxa de desemprego, à escala de freguesia, permitiu explicar os efeitos das OdC e das OdF no agravamento desta enfermidade. Do ponto de vista da caracterização das admissões por DPOC na AMP, concluiu-se que, em geral, esta doença está associada às freguesias com condições socioeconómicas mais precárias e com a população mais envelhecida. A intensidade e a duração, de acordo com o modelo utilizado, explicam o aumento nas taxas de admissões por DPOC durante os eventos de OdC e OdF. Todavia, a duração contribuiu mais nos eventos de calor e a intensidade nos eventos de frio. A severidade média foi o único parâmetro que não compôs o modelo.
Geopoética dos sentidos, a/r/tografia e o patrimoniável em chave descolonial: por uma poética do Sul
Authors: Mancilla Claudio Andrés Barría
Published: October 2019

O presente artigo propõe uma releitura dos conceitos de aura da arte (BENJAMIN), memória e identidade no contexto latino-americano em chave descolonial, isto é, tendo a diferença colonial como lócus de enunciação, para senti-pensar dispositivos de descolonização da memória e da escrita, em diálogo com os conceitos de geopoética dos sentidos e do patrimoniável (AMARAL) a partir de experiências a/r/tográficas vivenciadas em mergulhos poéticos no lugar, como mediação cultural e ativação de territórios realizadas na cidade do Rio de Janeiro, que questionam sobre outros patrimônios possíveis, contra o desperdício da experiência (SANTOS, 2010), em alinhamento a uma poética do Sul.
Ecotoxicity Study of Iron Oxide Nanoparticles on Chlorella Sp. and Daphnia Magna
Authors: ERTİT TAŞTAN Burcu , KARS DURUKAN İlknur , ATEŞ Mehmet
Published: October 2019

Nanoparticles have great impact due to their tremendous industrial
applications. However, their applications have produced toxicity effects on the
aquatic environments and their detailed analyses are not clearly understood.
Iron oxide nanoparticles (Fe2O3 NPs) are being used
extensively in many industries but are considered highly toxic to aquatic
species residing in surface waters. This paper demonstrates the acute
toxicity of a-Fe2O3 and g-Fe2O3NPs in two aquatic
species. The effects of various concentration (0, 50, 100, 250, 500 and 1000
mg/L) of a-Fe2O3 and g-Fe2O3 on the sensitivity
response of the Chlorella sp. and D. magna were investigated. The growth
of microalgal decreased with increased concentration of the a-Fe2O3 and g-Fe2O3 NPs concentrations but
did not show a significant toxic effect. The EC50 concentration
value was 500 mg/L and LD50 concentration value was 1000 mg/L for a-Fe2O3 treated daphnids in 72 h,
respectively. The findings demonstrate the significant evidence in
understanding acute toxicity of Fe2O3 NPs for environmental
protection as part of risk assessment strategies.
Editorial
Authors: Jama-Zambrano Victor Reinaldo
Published: October 2019

Editorial
DIVERSITY OF ARTHROPOD PREDATOR IN SWAMP RICE FIELDS IN SOUTH SUMATERA
Authors: Meidalima Dewi , Kawaty Ruarita Ramadhalina , B. Gunawan Erlan
Published: October 2019

The abundance and diversity of arthropod in agro ecosystem depend on the level of synthetic pesticide contamination.  This study aimed to explore, identify and analyze the diversity and abundance of predatory arthropods in swamp rice fields treated with pesticide application (in Pemulutan) and without pesticide application (in Musi 2). The swamp rice fields in Pemulutan are bordered by village, river and forest. The methods were survey and direct observation on 3 ha and 2 ha of swamp rice fields in Pemulutan and Musi 2, Palembang. Sampling of predatory arthropods were conducted at 20, 50, 80 and 110 days after rice planting using pitfall trap.  Identification of  predatory arthropods  was conducted at Laboratory of Entomology showing that the arthropod collected consisted of 17 species of insects and 9 species of Arachnida. In Pemulutan Ogan Ilir were found 19 species (10 species of insect and 9 species of Arachnida) at the village area. In the area that was bordered by river were found 8 species (7 insect and 1 Arachnida). In the area bordered by forest were found 22 species (10 species of insects and 12 species of Arachnida). The diversity level, number of species, and arthropod specimen in the field without pesticide application at Musi 2 were higher than those in the fields with pesticide application in Pemulutan.
GENOTYPIC SELECTION ON RED CHILI PLANTS RESISTANT TO ANTHRACNOSE DISEASE AT M2 GENERATION
Authors: Sa'diyah Nyimas , Adawiah Adawiah , Prasojo Ibnu , Rugayah Rugayah , Ratih Dirmawati Suskandini
Published: October 2019

Genotypic selection on red chili palnts resistant to anthracnose disease at m2 generation. A superior anthracnose resistant cultivar was sought to overcome the low production due to anthracnose in red chili. For the development of superior cultivars, it was necessary to select genotypes that were resistant to anthracnose. Selection effectiveness was determined by wide diversity and high reliability. The purpose of this study was to see the diversity and heritability of agronomic characters and resistance to anthracnose on chili plants, and to select genotypes that were resistant to anthracnose. This research was conducted with a design without repetition. The plant material used was the seed of the results of gamma ray mutations in generation M2. The results of this study were: the broad diversity of phenotypes found in all characters observed, while all characters of the genotype observed had broad criteria except plant height at flowering and harvest, and at seedling period. The genotype that should be planted in the next generation was genotype number 136. Genotype number 136 was very resistant to anthracnose infection.
Analysis of the Effectiveness of Learning in the Use of Learning Modules Against Student Learning Outcomes
Authors: Rahmawati Rika , Lestari Fitria , Umam Rofiqul
Published: October 2019

At present there are still students who have difficulty in learning, due to limited learning resources. One effort that can be done is the use of modules in learning. Modules are printed teaching materials designed to be studied independently by learning participants. This study aims to determine the effect of the use of modules on the learning outcomes of students in MTs Hasanuddin Teluk Betung. Through the analysis of diffrences in the average of mathematics learning outcomes between those who used modules and those who did not use modules. The method used in this study is experiments with quantitative exploratory levels. The basic data collection technique uses a test technique that is to determine students learning outcomes. Testing hypotheses by using the t-test statistical formula. Based on the results of hypothesis testing it was concluded that the average mathematics learning outcomes of students using modules were higher than students who did not use the module.
Management of Hemorrhage Related to Direct Action Oral Anticoagulant Medication
Authors: Ramos Ali Ganem Isabela , Behrmann Martins Luiz Claudio , Mendonça Tomé Carlos Eduardo
Published: October 2019

Introduction: Direct Oral Anticoagulant – DOACs) are a new class of anticoagulant that directly inhibit the trombine (dabigatran) or Xa factor (rivaroxabane , edoxabane and apixabane) in the coagulation cascade. These medications are being more frequently used for the treatment and prevention of thrombolytic events, mainly in patients with atrial fibrillation, in substitute to varfrine or other vitamin K antagonists (VKAs). Although the incidence of hemorrhage is higher in AVKs than in DOACs, these events may also occur in this group, even in the form of intracranial hemorrhage (ICH), with risk of death. Nowadays, DOACs indications have progressively enhanced and the availability of their specific reverse agents certainly will enhance the safety of their usage. Idarucizumab,
reverse agent of dabigatrane, and alpha andexanet, reverse agent of Xa factor, have been approved by the Food and Drug Administration in the United States and ciraparantag may be approved in a near future. Objective: To review the literature on the manage of hemorrhage related to the use of DOACs. Methods: Review of literature that used articles from 1998 to 2017, from several platforms and journals. Conclusion: DOACs constitute a great advance in prophylaxis and treatment of thrombolytic diseases, which presents elevated morbidymortality, and hemorrhages are the main adverse events related to their usage, being rarely necessary the immediate reverse of the anticoagulation. However, the existence of DOACs specific reverse agents enhance the safety of patients, whose anticoagulation may be rapidly reversed if necessary.
The relations between the quality of financial statements and corporate governance
Authors: Franczak Iwona
Published: October 2019

Business entities operated in the form of capital companies, to maintain reliability and transparency of the activities conducted, should observe general supervisory framework of legal nature. The primary objective of the information policy is to provide stock market participants with appropriate standards of company transparency which through the corporate governance regulations should lead to the improvement in the quality of financial reporting. Financial statements should be reliable as it is only then that their aims and targets are met, and the image of business they depict should be created according to the true and fair principle, invoking the responsibility of individuals supervising the process of drawing up a financial statement. The aim of the paper is to indicate the essence of the relationship between the quality of financial statements and the application of corporate governance principles. The paper uses the analysis of regulations and review of literature in the field of corporate governance and reporting of listed companies. The results of the analysis confirm that the quality of reported information determines the effectiveness of corporate supervision; that integrated reporting (IR) is a tool enabling organizations to communicate their value to investors; and that corporate supervision allows said organizations to adopt the comprehensive approach in developing sustainable value.
Gravelling Test for Rail Windshield
Authors: Bilar Adam , Boguszewicz Paweł , Perkowski Witold
Published: October 2019

During preliminary tests of locomotive windshield resistance to gravelling, according to the applicable standard PN-EN 15152:2007, carried out in the Institute of Aviation, the problem of the projectile overturning after leaving the cannon barrel was detected. Three tests recorded with a high-speed camera are presented in this article. This problem was found to be due to the incorrect projectile geometry.

In order to stabilise the trajectory of the projectile, four types of projectiles were made using military experience. All of them meet relevant test conditions from the point of view of the test piece (locomotive windshield). The best projectile modification was obtained in the tests with an average deviation of the expected impact angle of 11° compared to 75° for a projectile made exactly according to the guidelines of the standard. Each of 22 modified projectiles hit the test piece with the tip, while out of the 12 original projectiles only 4 hit the test piece with the tip. The impact test results confirm that it is possible to perform a gravelling test according to the standard concept, but it seems necessary to clarify the standard requirements and to modify the projectile shape.

The article contains a proposal for the projectile modification and highlights inaccuracies in the standard concerning the gravelling test.
Estimation of the Vessel's Sailing Resistance in the Preliminary Analyses
Authors: Charchalis Adam
Published: October 2019

In this article is presented the methodology of calculation of principal parameters of hull a vessel and resistance components. The approximate method is based on the analysis of the results of model tests and surrender tests presented in the literature. Ship owners' preliminary assumptions for new ship consist of deadweight, speed-shipping line and others. This goal needs definition of principal dimensions of a vessel, which are the basis for further calculations of hull’s resistance and evaluation of necessary power of main engine to fulfil shipping requirements. The route and its environment, type of cargo, quantity to be moved, and value of the cargo and port facilities are typical features, which will be considered when evolving the size, speed, and specification of a suitable ship. Specific service requirements will be similarly considered when evolving vessels such as warships, passenger ships or fishing vessels. Selection of main dimensions of vessel is limited by related to seaways or harbours characteristic and limitations rules regarding buoyancy, stability, hull strength, manoeuvring capability, etc. The influence of the main dimensions of the ship and their coefficients of maritime and strength properties of the ship were presented. Moreover, formulas for calculation of the ship's resistance components, such as friction resistance, and wave shape, as well as the results of calculations for different types of ships, for the assumed deadweight and speed of sailing, are presented.
Wavelet Transform in Vibroacoustic Diagnostic of Machines
Authors: Haller Piotr , Jankowski Antoni , Kaźmierczak Andrzej , Wróbel Radosław
Published: October 2019

This article discusses the use of wavelet decomposition in the diagnostics of vibrometric signals of an engine. Apart from presenting the possibility of using wavelets in diagnostics, the authors take up the subject of the applicability range of processing for stationary signals, which until now has been reserved for non-stationary signals. A unified definition of signal stationarity has been proposed, which is not based on statistics. The authors presented methods of wavelet decomposition of a vibrometric signal of combustion engine vibrations, measured with the use of LDV (Laser Doppler Vibrometry). Laser measurements allows for studying an object without ‘touching’ its housing. Basing on the relative velocity of engine vibrations, the authors indicate how reliable vibrations are in diagnostics. Despite higher costs, this measurement method gives better results (for specific cases) than acoustic studies. Transform – wavelet decomposition is a solution hardly ever used in machine diagnostics; it is more often applied in medicine and image recognition. The authors presented the differences that can be obtained for different levels of decomposition, and also presented the impact on the engine condition assessment through the use of filtering (windowing) the signal before decomposition.
Influence of Marine Main Engine Foundations on the Results of Vibration Calculations
Authors: Murawski Lech
Published: October 2019

The article presents an influence of foundations of slow-speed main engine body on the results of numerical analysis of the engine dynamic stiffnesses and thermal deformations. The engine body is much stiffer than its foundation pads and ship hull (double bottom) – boundary conditions of the engine. Especially for the high power, marine engines, the correct model of the boundary conditions plays a key role during the analyses. Therefore, modelling method of engine foundation (boundary conditions) of that kind of model is essential during the analyses. During shaft line alignment and crankshaft springing analyses, knowledge of dynamic stiffnesses characteristics and thermal displacements of radial (main) bearings is significant. Those data of marine main engine body are difficult to estimate because of lack of available documentation and complicated shape of the engine and ship hull. The article presents the methodology of the characteristics determination of the marine engine's body as well as the example of computations for a MAN B&W K98MC type engine (power: 40000 kW, revolutions: 94 rpm) mounted on a 3000 TEU (twenty-foot container equivalent unit) container ship (length: 250 m). Numerical analyses were performed with usage of Nastran software based on Finite Element Method. The FEM model of the engine body comprised over 800 thousand degree of freedom.
Subjective Risk Estimation of the Rare Event
Authors: Nguyen Hoang
Published: October 2019

In the safety engineering, the most frequently disadvantage in risk estimation is the lack of data. In such cases, we have to rely on subjective estimations made by persons with practical knowledge in the field of interest, i.e. experts. However, in some realistic situations, they may have uncertainty in the perceiving and evaluation of the problem considered or limited knowledge of the rare events, such as the consequences of the seagoing ship propulsion failures. The probabilistic models of the risk estimation turn out to be insufficient in modelling the subjective uncertainty. The fuzzy methods are viewed to be powerful in dealing with ambiguity and uncertainty that can be used to handle with the subjective estimation. This article addresses the intuitionistic fuzzy method in the subjective estimation of the ship propulsion failure consequences as rare event risk. In the article, a subjective model of the ship propulsion risk is developed as scenarios of the different subsequent consequences of loss of ship propulsion function until a seriously severe accident resulting in loss of seaworthiness. The model proposes an approach combining AHP method and intuitionistic fuzzy method to assess the occurrence probability and severe probability of these rare events based on the expert opinions. In order to show the applicability of the proposed model, a study case of the propulsion risk of the container carrier operating on the North Atlantic lines is conducted.
Determination of Coefficients of Energy Losses Occurring in a Constant Capacity Pump Working in a Typical Hydrostatic Drive
Authors: Skorek Grzegorz
Published: October 2019

In order to assess possibilities of energy saving during hydrostatic drive system operation, should be learned, and described losses occurring in system. Awareness of proportion of energy, volume, pressure, and mechanical losses in elements is essential for improving functionality and quality of hydrostatic drive systems characterized by unquestionable advantages. In systems with too low efficiency there is increase of load, mainly in case of pump load, which can lead to higher risk of failure, necessity of repair or replacement, as well as to shorten service life of system. Coefficients ki, given in subject literature by Paszota, describe relative value of individual losses in element. They make it possible to assess proportions of losses and assess value of energy efficiency (volumetric, pressure, mechanical) resulting from losses occurring at nominal pressure pn of system in which element is used. As a result, thanks to knowledge of coefficients ki of individual losses, it is possible to determine losses and energy efficiency of components operating in hydraulic system as well as efficiency of system with defined structure of motor speed control as function of speed and load coefficient of motor. Knowledge of coefficients of energy losses occurring in system elements (pump, hydraulic motor, conduits, and motor) allows building models of losses and energy efficiency of element working in system and energy efficiency of system as whole composed of elements. Mathematical models of losses and energy efficiency in system must take into account conditions resulting from applied structure of system, from level of nominal pressure, from rotational speed of motor driving pump shaft, from viscosity change of applied hydraulic oil. Article presents method of determining coefficients of axial piston pump used in typical hydrostatic drive system with proportional control. Values that can be assumed for these loss coefficients for other hydraulic pumps are also given.
Health Monitoring in Landing Gears
Authors: Skorupka Zbigniew , Tywoniuk Andrzej
Published: October 2019

Every mechanical construction loses its properties in time due to the usage wear that leads to malfunctions and, in the end, to failure. Widely used method of failure time prediction base on extended laboratory tests where a device is tested against fatigue and wear. This method is well established but is expensive, time-consuming, and costly. Another way of failure prediction is to calculate it using advanced algorithms what is faster and cheaper but less accurate than actual tests. Furthermore, both methods are not optimal due to the principle of operation based on simplified assumptions. In such cases, it is common to make the lifespan of the safety wise devices for example landing gears much less than real in case of fatal failure not covered by the predictions. This can lead to much higher price and maintenance costs of the landing gear. Nowadays the worldwide trend is to monitor the behaviour of the devices in real time and predict failure using actual state. There are several methods of health monitoring, most of them including sensors, acquisition systems and computer software for analysis.

In this article, authors describe possible landing gears health monitoring methods based on authors ’ laboratory experience in sensor appliance and test data analysis. The authors also present their idea of adding health monitoring to existing landing gears where no dedicated infrastructure was initially designed.
Modelling of Vane and Rotor Blade Rows in Simulations of Gas Turbine Performance
Authors: Sznajder Janusz
Published: October 2019

A method of modelling of nozzle and rotor blade rows of gas turbine dedicated to simulations of gas turbine performance is proposed. The method is applicable especially in early design stage when many of geometric parameters are yet subject to change. The method is based on analytical formulas derived from considerations of flow theory and from cascade experiments. It involves determination of parameters of gas flow on the mean radius of blade rows. The blade row gas exit angle, determined in turbine design point is a basis for determination of details of blade contour behind the throat position. Throat area is then fixed based on required maximum mass flow in critical conditions. Blade leading edge radius is determined based on flow inlet angle to the blade row in the design point. The accuracy of analytical formulas applied for definition of blade contour details for assumed gas exit angle was verified by comparing the results of analytical formulas with CFD simulations for an airfoil cascade. Losses of enthalpy due to non-isentropic gas flow are evaluated using the analytical model of Craig and Cox, based on cascade experiments. Effects of blade cooling flows on losses of total pressure of the gas are determined based on analytical formulas applicable to film cooling with cooling streams blowing from discrete point along blade surface, including leading and trailing edges. The losses of total pressure due to film cooling of blades are incorporated into the Craig and Cox model as additional factor modifying gas flow velocities.
An Overview of Different Possibilities to Master the Challenge of Coupling an AE-Sensor to an Object of Interest Partly Using Examples of Previous Investigations
Authors: Ziegler Burkhard , Dudzik Krzysztof
Published: October 2019

Acoustic emission analysis is defined as a passive, non-destructive investigation method, which only listens for AE-waves (AEW), generated actively by an object of interest. Therefore, the AEW must have the possibility to propagate from their source to an acoustic emission sensor (AES). By virtue of the piezoelectric effect, the AEW transmitted into electrical signals inside of the AES. During the analysation of these electrical signals we earn–online–information about the object of interest, e.g. the operating characteristic of a machine or the strength of the friction of a tribolocical system. To enable the AEW to propagate into the AES, the sensor has to be fixed suitable onto the object of interest. Hereby has to be strictly respected, that the sensor is fixed in a reproducible mechanical way as well as to ensure that the through-transmission has a weak attenuation (couplant). Standard AES have the shape of a circular cylinder (diameter and height depend on the operation purpose), the AEW pass through one of the frontends into the sensor. The objects of interest can have different geometry of the surface (e.g. plane, cylindrical, unspecific) or temperatures which usually conflicting the operating range of the sensor. Depending on the operational purpose, there are many different couplants to use. This article offers help to master the different connecting challenges within the range of acoustic emission analysis.
Are We Ready for Electric Cars?
Authors: Karczewski Mirosław , Szczęch Leszek , Polak Filip
Published: October 2019

Cars with electric drive are becoming more fashionable. More and more of them appear on the roads, especially in the centres of big cities. However, electric cars must be charged, preferably from high-power energy sources. In domestic environment, (if somebody owns a house) power available is usually of 10-16 kW. Users have to increase the level of household power or charge the car for several hours, because car charger is not the only home energy receiver. Some of the users are installing energy storage systems solution based on energy storage systems but this require additional expenses for batteries, inverter, circuit breakers and additional equipment. Other disadvantages of such solution are that they are mostly dedicated for stand-alone houses. What could be done by electric cars owners who live on the 10th floor in a block of flats? What would happen if everyone in the same time decided to buy an electric car? What will happen if everyone at the same time charges his or her cars? Do we have an adequate supply of energy potential? On the other hand, do we need to build new energy power plants? Will the electric grid cope with such a load or will have to build new transmission lines, transformer stations, and charging stations?
Models of the Reference Departure and Arrival IFR Procedures for the Purpose of Research in RPAS Integration in Controlled Airspace
Authors: Lichoń Daniel , Orkisz Marek
Published: October 2019

The air operations in controlled airspace performed according to Instrument Flight Rules (IFR) are composed of three main flight phases, i.e. departure, cruise, arrival. Controlled airspace is divided into the terminal area and en-route airspace. The terminal area encloses the departure and arrival phases while the en-route airspace encloses the cruise phase. The IFR procedures are designed for manned aviation to ensure the safety of air operations. Development of the aviation concerns among others the increase in the number of unmanned aviation operations. Currently, on the European level, there is an on-going, long-term program of integration of the unmanned aviation in the uniform (non-segregated) airspace. This work concerns the research in the integration of the Remotely Piloted Aircraft Systems (RPAS) in the IFR procedures of the controlled airports. The objective was to build the reference models of Standard Instrument Departure and Arrival Procedures (SID and STAR). Basing on the procedure design guidelines the models of procedural nominal track, tolerance area, obstacle clearance area, climb or descend gradient, manoeuvres in SID and STAR were done. The guidelines describe the operational minima thus the statistics of existing procedures was done to select the suitable procedure parameters such as a number of navigational points, segments lengths, altitudes, climb or descent gradients. Reference models of SID include straight departure and turning departure procedures. Reference models of STAR include non-precision approach procedures according to used navigational aids, i.e. GNSS, VOR. The reference procedures were numerically implemented which will be used in the further works on RPAS integration problem by simulations of the RPAS ability to execute of the SID and STAR.
The Full or Partial Replacement of Commercial Marine Engine Oil with Bio Oil, on the Example of Linseed Oil
Authors: Malinowska Małgorzata
Published: October 2019

The bio-oils are considered to sustainable, alternative and environmentally friendly source of lubricants compared to commercial engine oils, on the base a mineral, synthetic or semi-synthetic. They are obtained from natural raw material (vegetable or animal oils), which are renewable and non-toxic to humans, living organisms and environment. The vegetable oils called green oils, natural oils, bio-oils or natural esters. They can be obtained from plant seeds, that may be consumed – edible oils (for instance: rapeseed oil) or which cannot be consumed – inedible (for example: linseed oil).

The conducted research into linseed oil and its different quantity additives (25% and 50%) to commercial marine mineral oil intended for a medium-speed 4-stroke, trunk marine engine (i.e. Marinol RG 1240). The flash point and dependence of viscosity and temperature were compared and assess. It has been proven that vegetable oils have a high ignition temperature and very small viscosity change in the range of temperatures presented, i.e. high viscosity index.

According to the results, it can be recommended the addition of 25% linseed oil in the base lubricant is the relevant for lubricating a medium speed 4-stroke marine engine. The vegetable additives can improve a viscosity index a lube oil, and they will be positively affected environmental protection.
Characteristics of Carbon Dioxide and Product Water Exhausts in a Direct Methanol Fuel Cell with Serpentine Channels
Authors: Nakashima Kohei
Published: October 2019

This study utilized a transparent direct methanol fuel cell, with serpentine channels with a width of 2 mm and an initial depth of 2 mm, and investigated the relationship between the behaviours of carbon dioxide (CO2) slugs, product water accumulations, and voltage fluctuation. It examined the exhaust volumes of CO2 slugs and product water accumulations from the channels over time, comparing an anode channel with a depth of 1.2 mm to one with a depth of 2 mm (without changing the cathode depth of 2 mm, nor the width of 2 mm in both the anode and the cathode). Results indicated that cell voltage fluctuated, rising while CO2 slugs were ejected, and falling between ejections. In the case of an anode channel depth of 2 mm and a lower methanol-water solution flow rate, CO2 slugs were ejected less frequently, so cell voltage fluctuated widely. (Product water accumulations in the cathode had a minimum effect on this cell voltage fluctuation.) In the case of a higher methanol-water solution flow rate, CO2 slugs were ejected more frequently, with less exhaust volume per CO2 slug, reducing the fluctuation in cell voltage. Finally, with an anode channel depth of 1.2 mm, the exhaust volume per CO2 slug became even smaller, and these small CO2 slugs were rapidly ejected. With this shallow depth, the cell voltage increased with a lower methanol-water solution flow rate, but decreased with a higher methanol-water solution flow rate by crossover.
Analysis of Ratios of Propulsion Energy Demand for Transport by Bulk Carriers
Authors: Polanowski Stanisław
Published: October 2019

The article presents the results of calculations and analysis of the eM ratio of the propulsion energy consumption per the nautical mile and the eMt ratio of the propulsion energy demand for the transport of 1-ton cargo per the nautical mile for bulk carriers. The relationship between eM and eMt indicators with the EIV (Estimated Index Value) ratio is shown. The output data for the determination of eM and eMt indicators was taken from the quoted MAN publication, reading (reproducing) the values of power, velocity v and DWT tonnage from the charts included in this publication. Calculations and analyses were made for velocity v between 11-15 knots and for DWT from 5-400 kt (kilo tonnes). The graphs of eM and eMt ratios in the function of speed v and load capacity DWT are presented. Using the stepwise method of least squares, models of statistical dependence of indicators on velocity v and load capacity of bulk carriers were developed. They were based on generalized polynomials with integer exponents. Derivatives deM / dv and deMt / dv and derivatives deM / dDWT and deMt / dDWT were determined. The main observations resulting from the conducted analyses are observed with the increase of DWT (within the range of 80-100 kt) a significant decrease in the value of the eM index. For DWT values> 100 kt, the decrease in eMt is slow − eMt asymptotically tends to a constant value. The results of the analyses carried out can be used at the stage of designing the transport capacity (tonnage) and nominal speed of the ship as well as selection of ship tonnage and travel speed in a given transport situation.
Strength Analysis of Polymer Conical Gear Wheel Made with 3D Printing Technique
Authors: Śpiewak Szczepan , Awrejcewicz Jan
Published: October 2019

The article deals with the problem of designing conical gears with a curved line contour. The contour of the tooth flank is described by means of a helix and involutions. In the work, a conical gear designed to drive of the lower limb rehabilitation exoskeleton has analysed. Parameters of the conical gearbox have been adapted to design requirements of the exoskeleton. Gear wheels were made with ABS material using 3D printing technique. The article presents the results of strength calculations obtained using the method classical design of the gear wheals described in the norm ISO 6336-1996. In the strength calculations, bending and contact stresses were taken into account. Creating the contour of gears was aided through the gearbox wizard available in Inventor program. The work contains the results of a static tensile test of the material from which the gear wheels were made. In experimental and numerical studies, the orthotropy of the material used was taken into account. The orthogonal values of the Young’s modulus, the Poisson’s ratio and the Kirchhoff’s modulus were determined. The publication also includes partial results of fatigue tests in the area of normal stresses. In the research used to finite element method (FEM), determine of internal loads in the gear. A structure of the FEM model is described in detail. Maximum values of contact pressures determined by use to FEM models have been compared with the results obtained on the basis of Hertz’s formulas. The article presents basic geometrical and strength parameters of the designed gear. The work demonstrates the validity of the material models used. Limitations in the application of the classic method of calculating conical gears made of orthotropic materials have been indicated. The results of analytical and numerical calculations are presented in tabular and graphical form.