bluuebunny/crossref_metadata_2025 huggingface dataset:
Curvilinear Moderation of Perceived Co-Worker Support on Bullied Health Professionals: Timelag Study
Authors: Hamid Sarah
Published: May 2021

Objectives.  The research highlights the role of co-worker’s support in bullied health professionals. Investigating the extend of support, firstly, how it helps the bullied professionals not to quit their jobs. Secondly, how the continued constant and increased support from co-workers drastically change it to higher turnover intention.

Material and Methods. Data was gathered from 300 health professionals working in different hospitals in two time-lags with the lapse of almost 6 weeks using convenience sampling technique.

Results. Data analysis revealed the strong positive connection between workplace bullying and turn over intention posing alarming challenge for health professionals and organizations as well. Further the research proved the strong impact of lower and higher levels of perceived co-worker support in manipulating the decision of bullied professionals to turnover.

Conclusion. Workplace bullying is on alarmingly rise affecting the health sector as well and it is the worst type of social stress being evident at workplaces causing serious medical errors and list goes on. This Research helps to understand the role of co-worker’s support on victims opening new avenues, adding new variable for future research on bulling culture.
Brain Tumor Radiotherapy Role and Variation
Authors: Abu Nahlah Eyad Lutfi , Aljubour Raed M. , Abu  Salma Zuhair , Lozi Rakan A. , Alkhawaldeh Hamzeh M. , Al-Hanaqta Motasem M. , Al-Rawabdeh Sura
Published: May 2021

Objectives: We report our experiences of brain tumors management by surgery and radiotherapyWhether It has been used as adjuvant, radical or palliative therapy belonging to benign or malignant tumors over 2 years period at ENT,  neurosurgery and radiotherapy departments royal medical services.
Methods: We used a retrospective study design to review all brain tumor patients(benign, malignant or metastatic) operated in neurosurgical department and referred to radiotherapy after discussing each case in multidisciplinary clinic in 2018 and 2019. Patient files, radiological images computed tomography (CT) or magnetic resonance imaging (MRI) scans), histo-pathological reports and radiotherapy management plan were reviewed for patients.
Results: In total, 137 patients with brain tumor managed byradiotherapy 64 patients were metastatic, 37 patients high grad glioma, 12 patients atypical meningioma, 7 patients medulloblastoma, rest of cases discussed in the study  .
Conclusions: Radiotherapy has been fulfilling crucial part in the treatment of CNS tumors, where it has been implemented as adjuvant therapy or even being the solitary resort where surgery is inapplicable or used as palliative therapy in different regimens according to histopathology, performance status and different sites.
Quantum-chemical studies of rutile nanoparticles toxicity II. Comparison of B3LYP and PM6 data
Authors: Breza Martin
Published: May 2021

The relation between copper atomic charges and metal-ligand interaction energies obtained by PM6 and DFT-B3LYP methods for cytotoxicity prediction of model rutile nanoparticles [Ti40O124H81]7–, [Ti7O28H26]2–, [Ti2O10H10]2–, [Ti7O30H30]2– and their Cu(II) complexes is investigated. Except for Mulliken charges, very good statistical parameters were obtained for the linear relation between the results obtained by both methods if standard accuracy of quantum-chemical calculations is achieved.
Rota-Baxter operators and Bernoulli polynomials
Authors: Gubarev Vsevolod
Published: May 2021

We develop the connection between Rota-Baxter operators arisen from algebra and mathematical physics and Bernoulli polynomials. We state that a trivial property of Rota-Baxter operators implies the symmetry of the power sum polynomials and Bernoulli polynomials. We show how Rota-Baxter operators equalities rewritten in terms of Bernoulli polynomials generate identities for the latter.
Entropy in Thermodynamics: from Foliation to Categorization
Authors: Kycia Radosław A.
Published: May 2021

We overview the notion of entropy in thermodynamics. We start from the smooth case using differential forms on the manifold, which is the natural language for thermodynamics. Then the axiomatic definition of entropy as ordering on a set that is induced by adiabatic processes will be outlined. Finally, the viewpoint of category theory is provided, which reinterprets the ordering structure as a category of pre-ordered sets.
Crystallographic actions on Lie groups and post-Lie algebra structures
Authors: Burde Dietrich
Published: May 2021

This survey on crystallographic groups, geometric structures on Lie groups and associated algebraic structures is based on a lecture given in the Ostrava research seminar in 2017.
Circulant matrices with orthogonal rows and off-diagonal entries of absolute value 1
Authors: Contreras Daniel Uzcátegui , Goyeneche Dardo , Turek Ondřej , Václavíková Zuzana
Published: May 2021

It is known that a real symmetric circulant matrix with diagonal entries d ≥ 0, off-diagonal entries ±1 and orthogonal rows exists only of order 2d + 2 (and trivially of order 1) [Turek and Goyeneche 2019]. In this paper we consider a complex Hermitian analogy of those matrices. That is, we study the existence and construction of Hermitian circulant matrices having orthogonal rows, diagonal entries d ≥ 0 and any complex entries of absolute value 1 off the diagonal. As a particular case, we consider matrices whose off-diagonal entries are 4th roots of unity; we prove that the order of any such matrix with d different from an odd integer is n = 2d + 2. We also discuss a similar problem for symmetric circulant matrices defined over finite rings ℤ
m
. As an application of our results, we show a close connection to mutually unbiased bases, an important open problem in quantum information theory.
A look on some results about Camassa–Holm type equations
Authors: Freire Igor Leite
Published: May 2021

We present an overview of some contributions of the author regarding Camassa–Holm type equations. We show that an equation unifying both Camassa–Holm and Novikov equations can be derived using the invariance under certain suitable scaling, conservation of the Sobolev norm and existence of peakon solutions. Qualitative analysis of the two-peakon dynamics is given.
Metric groups, unitary representations and continuous logic
Authors: Ivanov Aleksander
Published: May 2021

We describe how properties of metric groups and of unitary representations of metric groups can be presented in continuous logic. In particular we find Lω

1

ω
-axiomatization of amenability. We also show that in the case of locally compact groups some uniform version of the negation of Kazhdan’s property (T) can be viewed as a union of first-order axiomatizable classes. We will see when these properties are preserved under taking elementary substructures.
Perioperative nursing principles guided by the concept of enhanced recovery after surgery†
Authors: Xie Hong-Jie , Cui Fan , Shuang Wei-Bing
Published: May 2021

Objective

To explore the clinical effect of perioperative nursing guided by the concept of enhanced recovery after surgery and summarize them.

Methods

Pubmed, Chinese National Knowledge Infrastructure (CNKI), Chinese Biomedical Literature Database (CBM), Wanfang Database, and VIP Database were searched to obtain the relevant literature involving enhanced recovery after surgery (ERAS) guidance, obtain the effective clinical data, review the reports in literature, and obtain the effective scheme.

Results

Compared with the traditional nursing program, perioperative nursing principles guided by the concept of ERAS provide more accurate nursing care to patients and reduce the occurrence of intraoperative stress events through comprehensive nursing measures such as preoperative pre-rehabilitation measures, intraoperative body temperature and fluid management, postoperative analgesia, prevention of nausea and vomiting, early mobilization, catheter nursing, and better out-of-hospital follow-up.

Conclusions

Perioperative nursing principles guided by the concept of ERAS can significantly reduce the incidence of perioperative complications, shorten the hospital stay of patients, and promote postoperative rehabilitation of patients. The transformation and implementation of this concept can bring significant benefits to hospitals, medical care, and patients.
Effects of mother–child interaction on school adaptation of children according to maternal depression
Authors: Lee Hanna , Han Jeong-Won
Published: May 2021

Objective

Factors influencing school adaptation of school-aged children include both executive function (EF) and parent–child interaction. This study aims to investigate the developmental trajectory of mother–child interaction longitudinally using latent growth model analysis.

Methods

A longitudinal descriptive survey study was conducted. The participants comprised of 1,614 mothers and school-aged children, who participated in the Panel Study on Korean Children (6th–8th panel surveys). A model was designed and analyzed using latent growth modeling to estimate the pattern of change over time.

Results

In the group where the maternal depression was within the normal range, only the path by which the change rate of mother–child interaction affected school adaptation of children was statistically nonsignificant (t = 1.007, p = 0.314). In the group where maternal depression was mild or higher, only the paths by which the initial value of mother–child interaction affected EF difficulty (t = −2.75, p = 0.032) and EF difficulty affected school adaptation (t = −7.876, p < 0.001) were statistically significant.

Conclusions

This study confirms the research models developed by dividing mother–child interaction into two groups according to depression levels (i.e., normal range and mild or higher-level depression). The findings provide a basis for construction of individualized interventions.
Correlation among academic self-efficacy, professional identity, and professional attitude of higher vocational nursing students†
Authors: Xu Tian-Liang , Zhao Jiang-Nan , Zhang Yan-Yan , Jing Gai-Li
Published: May 2021

Objective

To analyze the influence of professional identity and academic efficacy on the professional attitude of higher vocational nursing students.

Methods

A total of 656 higher vocational nursing students were investigated with general information questionnaire, academic self-efficacy scale, professional identity scale, and professional attitude scale of nursing students.

Results

The score of professional attitude of higher vocational nursing students was (106.34 ± 9.86), which is found to be in the upper middle level. The professional attitude of higher vocational nursing students is positively correlated with academic self-efficacy (P< 0.05), and with learning ability self-efficacy (P< 0.01). Professional cognition, professional will, and professional values have a positive predictive effect on the professional attitude of higher vocational nursing students (P< 0.05).

Conclusions

Academic self-efficacy and professional identity are important predictors of professional attitude. Learning behavior self-efficacy, professional cognition, professional will, and professional values have a significant impact on the establishment of positive professional attitude.
Research on the effects of family care degree on stigma and psychosocial adaptation among the patients with Parkinson’s disease†
Authors: He Yue-Yue , Yin An-Chun
Published: May 2021

Objective

This study aimed to investigate the status quo of family care degree, stigma and psychosocial adaptation of the patients with Parkinson’s disease (PD), and discuss the effects of family care degree on stigma and psychosocial adaptation among the patients with PD.

Methods

This study was conducted between September 2018 and April 2019 on patients with PD who were admitted to a Tertiary Grade A hospital in Dalian city. A total of 246 PD patients were investigated by convenience sampling method using self-designed general information questionnaire, along with family care index (APGAR), 24-item Stigma Scale for Chronic Illness (SSCI), and Psychosocial Adjustment Scale (PAS) for PD. And patients were divided into two groups according to the level of family care degree and compared with stigma and psychosocial adaptation.

Results

The total score of family care for patients with PD was 6.97 ± 2.46, family function was good in 132 cases (53.7%), moderate barrier in 92 cases (37.4%), and severe barrier in 22 cases (8.9%). The scores of stigma and psychosocial adaptability and their dimensions in the group with high degree family care were higher than the low degree group.

Conclusions

The overall level of family care for PD patients was poor. Improving family care degree can help patients with PD to reduce stigma and improve psychosocial adaptation.
Investigations on the Luminescence Properties of Quartz and Feldspars Extracted from Loess in the Canterbury Plains, New Zealand South Island
Authors: Brezeanu D. , Avram A. , Micallef A. , Cinta Pinzaru S. , Timar-Gabor A.
Published: May 2021

The applicability of the single-aliquot regenerative-dose (SAR) protocol, by using the optically stimulated luminescence (OSL) signal of quartz as well as the post-infrared–infrared (pIRIR) signals of polymineral fine grains, namely pIRIR225 and pIRIR290, was assessed for dating loess in New Zealand South Island. OSL signals of quartz grains displayed low sensitivity. However, the application of repeated irradiation/bleaching cycles did not result in an increase in sensitivity; annealing in the 300–500°C temperature range generated the sensitisation of both the 110°C thermoluminescence (TL) peak as well as the OSL signal, likely by activation of yet unidentified luminescence centres. After heating, the quartz signal is comparable to that of ideal samples, but the annealing is precluding successful dating. On the other hand, feldspar infrared-stimulated signals displayed satisfactory properties, allowing estimation of ages ranging from 14 ± 1–29 ± 3 ka for the investigated deposit. It was shown that pIRIR225 and pIRIR290 methods have potential for dating loess in the South Island of New Zealand, based on the following observations: (i) Dose recovery tests were successful with recovered-to-given dose ratios with a <10% deviation from unity, (ii) constant residual values of about 4 Gy and about 10 Gy were obtained after exposures for 48 h in the case of pIRIR225 signals and 96 h in the case of pIRIR290 signals, respectively, (iii) while a slight dose-dependence of the residual was reported, and for a dose as large as 1600 Gy the residual values are ≅9 Gy and ≅19 Gy for pIRIR225 and pIRIR290 signals, respectively.
Facilitating the employment of people with mental health difficulties in Ireland
Authors: Tighe Margaret , Murphy Caroline
Published: May 2021

The promotion of practices supporting positive mental health at work is increasingly important on employers’ agendas. However, within the HRM literature there is a relative dearth of research on how employers can facilitate reintegration into the workplace or first-time employment for employees with mental health issues. Publicly funded supports are emerging as a strategy that can provide targeted supports to both workers and employers. This paper aims to investigate the effectiveness of this approach by undertaking triadic research with employers, healthcare professionals, and workers using the service in the Irish context. We make recommendations regarding the enhancement of opportunities currently available to those with a mental health difficulty to return to and remain in employment. The paper contributes to our understanding of the nature of supports required to successfully facilitate employing or re-integrating those with a mental health disability or history of mental health problems into the workplace.
Perceived self-efficacy of students in a business simulation game
Authors: Dumblekar Vinod , Dhar Upinder
Published: May 2021

Self-efficacy is an individual's confidence in the personal ability to complete a task under specified conditions. Game self-efficacy is the belief of game players that they would win in a business simulation game competition. To understand the composites of such belief, an instrument of 30 statements was developed and statistically tested on 227 undergraduate students at the end of a business simulation game competition. The factor analysis produced eight factors of perceived game self-efficacy, namely, innovation, experimentation, conviction, openness, focus, proactivity, conceptualisation and determination. These factors have significant research implications for goal-oriented behaviour, goal setting and performance enhancement at work and in games and competitions, and in developing simulation games.
Multilateral teaching in physical education improves resilience and self-efficacy in adolescents and could help reduce bullying behaviors
Authors: Greco Gianpiero
Published: May 2021

Youth with higher levels of resilience and self-efficacy are less likely to engage in aggressive behaviors or be victims of bullying. Previous anti-bullying approaches have often achieved no reduction in bullying behavior. Thus, the aim of this study was to examine the effect of 12 weeks of extracurricular multilateral teaching on the risk for students (aged 14–16 years) to be involved in bullying. Sixty male students were allocated to an experimental group (n = 30) that performed psychoeducational activities combined with physical exercise training and team games (90 min, 2d · week–1) or a control group (n = 30). Before and after the intervention, we used the Child and Youth Resilience Measure (CYRM-28) to assess individual capacities and resources, relationship with primary caregiver, contextual factors, and total resilience; and the Self-Efficacy Questionnaire for Children (SEQ-C) to measure academic, social, emotional, and total self-efficacy. Four participants from the experimental group withdrew. Significant improvements of crucial relevance were found for the resilience and self-efficacy scales (p < 0.05) in the experimental group. We found that multilateral teaching may improve resilience and self-efficacy in adolescents and make them less likely to engage in aggressive behavior or be bullied. Multilateral teaching should be considered an effective alternative to the anti-bullying approach, highlighting the crucial role of physical education teachers in the promotion of proactive educational strategies to reduce bullying behaviors.
How football fans perceive sports heroes – The case of Israel
Authors: Levental Orr , Nudelman Shira Ben-Amram
Published: May 2021

Background: Hero-making and hero-worship are common in human society. Yet despite the universal appeal of heroes, the features attributed to these figures and the attitudes toward them change depending upon the circumstances. Heroes have been the topic of extensive discussion in the academic literature. Nevertheless, little research attention has been directed at sports heroes. Examining soccer heroes is of special importance, particularly in view of soccer’s popularity across the globe and the celebrity status of top soccer stars.

Purpose: The objective of this paper is to examine and map the defining features of soccer heroes as subjectively perceived by their fans.

Methods: We conducted a qualitative study that entailed semi-structured interviews with 18 young Israeli soccer fans as well as content analysis of fan chants.

Results: The research findings indicate that fans attribute special importance to three main characteristics that are not perceived as dominant among heroes in other contexts: loyalty to team and family, modesty and morality, and the ability to influence their surroundings. Based on the findings, the paper discusses the unique nature of soccer heroes in contrast to other elite players and the role played by these heroes for their fans.
A case study: the AFL as a positive institution
Authors: Densten Iain
Published: May 2021

The Australian Football League (AFL) is a leading professional sports organization within the multi-billion-dollar entertainment industry. This case study uses publicly available information to investigate the AFL in terms of its credentials as a positive institution using the good work model developed by Stansbury and Sonenshein (2012). The AFL has taken advantage of the economic rationalism and developed a corporate structure able to deliver a range of good work activities. For example, developmental programs that help players exceeding high community expectations. This study suggests that the good work model is beneficial for cognitive resources, normal functioning, regulatory focus, and impression formation. The AFL appears to answer Cameron et al. (2004) call to identify and enable flourishing and life-giving aspects of their organisation and, thus, represents a kind of positive institution. Finally, the study recognizes positive institutions as worthwhile but raises concerns about the uniqueness and lack of cultural research.
Individual knowledge of, perceptions about, and barriers to physical literacy (PL) in Malaysia
Authors: Zulkifli Ahmad Fahim , Danis Ajau
Published: May 2021

The purpose of this study was to evaluate individuals’ knowledge of, perceptions about, and barriers to promoting physical literacy (PL) in Malaysia. Random samples of 360 participants of different genders, ages, races, and education levels (aged 15–60 years) residing in Malaysia participated in this study, which was conducted on online platforms between the months of February and May, 2019. The participants’ knowledge was assessed using a modified Physical Literacy Knowledge questionnaire (PLKQ). Open-ended questions were also conducted to assess perceived perceptions and barriers to improving participants’ PL, thus strengthening the validity and reliability of data collection. Quantitative data were analyzed using descriptive statistics (e.g., means, SD) and the Pearson correlation coefficient, while the analysis of qualitative data involved the usage of the Interpretive Phenomenological Approach (IPA). The participants showed greater efficacy about standards in physical education and believed that PL is developed throughout one’s lifetime, with (M = 3.2, SD = 1.02) and (M = 3.78, SD = 1.02), respectively. Additionally, most participants pointed to the necessity of having specific skills and experience to develop PL among young people as the main barrier to improving PL in Malaysia, with (M = 3.25, SD = 1.02). This initial study will provide better direction for future researchers and educators to plan an intervention to increase PL among Malaysians and advocate for physical activity in individuals’ daily lives. Additionally, this study will be useful to inform future educators’ teaching practices, particularly in Malaysian schools.
Sport as a tool for public diplomacy in Hungary
Authors: Garamvölgyi Bence , Dóczi Tamás
Published: May 2021

Sport is often utilized as a tool by governments and nation-states in building a favorable international image, seeking external political legitimacy, and strengthening nation-building endeavors across borders. Given its universal appeal, sport is often perceived as a valuable soft power asset for conveying positive messages to foreign publics. Against this backdrop, the present study aims to introduce the sports diplomacy approach of Hungary, specifically focusing on the state-led utilization of sport in public diplomacy under the recent government of Viktor Orbán (2010–2020). With the institutionalization of sport in public diplomacy, Hungary has become a pioneering country in Central and Eastern Europe that can provide an example for other nation-states in the region. The Hungarian government’s sports diplomacy ambitions have not been curbed by the COVID-19 pandemic, and the country continues to invest large amounts of public funding in attracting and organizing international sporting competitions. Hosting the Summer Olympic Games in Budapest remains the ultimate goal of the current government’s sports diplomacy strategy, which focuses on elite sport.
Selected Risks of the Decompression Process. Part I: Selected Inherent Residual Risks in the Decompression Process
Authors: Kłos Ryszard
Published: May 2021

A safe transition from a higher-pressure atmosphere to a lower-pressure atmosphere is achieved by means of a planned decompression process, usually through changes in pressure and/or the composition of the breathing mix as a function of time. However, the decompression process is influenced by a greater number of inherent1 factors than merely changes in pressure and composition of the breathing mixture, the values of which should be maintained within certain ranges. However, there are instances where control over them cannot be maintained, leaving elements of residual risk2 to the decompression process. The safety of decompression should be assessed, inter alia, by analysing this risk for each implementation of the decompression process.
Evaluation of EEG Tests in the Amateur Diving Instructor Group and Correlation with the Occurrence of Sterile Bone Necrosis
Authors: Filipek Bogumił , Roman Stefan
Published: May 2021

The research undertaken was a continuation of previous studies relating to professional divers. The bioelectrical activity of the brain with an electronic electroencephalograph (EEG) was studied in a group of 89 instructors for amateur diving between 21 and 50 years of age. Pathological patterns were found in 15.7% of the subjects. In comparison with professional divers, the disturbances were significantly less frequent, but considerably more frequent in comparison with the control group. There was no relationship between the occurrence of the disorders in relation to the age of the examined person, however, the occurrence of the disorders was more frequent in persons with the least experience. Moreover, a correlation was found in one age group between abnormalities of EEG recording and the occurrence of sterile bone necrosis.
Pulmonary Barotrauma During Hypoxia in a Diver While Underwater
Authors: Kierznikowicz Brunon , Wolański Władysław , Olszański Romuald
Published: May 2021

The article describes a diver performing a dive at small depths in a dry suit, breathing from a single-stage apparatus placed on his back. As a result of training deficiencies, the diver began breathing from inside the suit, which led to hypoxia and subsequent uncontrolled ascent. Upon returning to the surface, the diver developed neurological symptoms based on which a diagnosis of pulmonary barotrauma was made. The diver was successfully treated with therapeutic recompression-decompression.
Epidemiology of Basal Cell Carcinoma – Observations of One Department
Authors: Borzęcka-Sapko Agnieszka , Siermontowski Piotr , Mleczko Mateusz , Borzęcki Andrzej
Published: May 2021

Introduction. Basal cell carcinoma is the most common malignant skin cancer. It is one of the so-called nonmelanoma skin cancers, the incidence of which has increased rapidly worldwide in recent years. Unfortunately, the National Cancer Registry in Poland does not classify basal cell skin cancer separately. Therefore, the precise data on the incidence in the population remain unknown.

Work objective. Retrospective analysis of the incidence of basal cell carcinoma in NZOZ Med-Laser in Lublin in the years 2005 – 2015 depending on gender, age group, place of residence (urban-rural) and clinical form of the disease.

Material and methodology. The data of NZOZ Med-Laser from the years 2005 - 2015 were used in the study. The data concern all patients with histopathologically diagnosed basal cell carcinoma, who during the period covered by the study were consulted either as outpatients or hospitalised in an institution providing dermatological services under contract with the National Health Fund (NFZ). Patients were divided into several groups depending on gender, age and place of residence. All groups were compared quantitatively and the results are shown in the figures below.

Results. The data collected indicate that between 2005 and 2015 a total of 922 patients with basal cell carcinoma received dermatological treatment. Over the years, there has been a clear increase in the number of patients with basal cell carcinoma. The disease occurred mainly in people over 59 years of age, with the majority of women living in cities. The most common locations of the cancer are nose, cheeks, forehead and temporal area. Histopathologically, solidum, superficiale, exulceratum and pseudoadenoides were the most frequently diagnosed forms.

Conclusions. Basal cell carcinoma of the skin is frequent in our society. Its incidence has been increasing in recent years. Therefore, action should be taken to create consistent international registries to gather reliable epidemiological data that would show the scale of the problem, which we are dealing with almost all over the world.
A Combined Method to Predict Impact Pressure on Planing Craft
Authors: Tahmasvand Hossein , Zeraatgar Hamid
Published: May 2021

Prediction of the pressure distribution on a planing craft in waves deeply affects its structural design and safe operation. In this paper, the possibility of pressure prediction for the planing craft in waves is studied. A combined method is formulated by which craft motions in waves are computed using a 2.5D method, and the impact pressure is anticipated by the equivalent wedge method. Experiments are conducted to record the vertical acceleration and pressure time trends on a model. Comparing the results of the combined method with the experiments indicates that this approach successfully predicts the heave and pitch motions and the time evolution of the acceleration and pressure. The method presents good estimations for the peaks of the acceleration and pressure. Using the combined method, a parametric study on maximum peak acceleration and pressure is also conducted for various forward velocities and wave heights. It has been shown that the combined method is a fast and reliable tool for maximum peak pressure prediction. The method may be employed for structural design and optimization.
Prediction of Ship Motions in Irregular Waves Based on Response Amplitude Operators Evaluated Experimentally in Noise Waves
Authors: Bielicki Sebastian
Published: May 2021

The most common methods for predicting ship roll motions in a specified sea state are direct measurements of motions in a representative irregular wave realisation (time domain) or calculations of motions from response amplitude operators (RAOs) in the frequency domain. The result of the first method is valid only for the tested sea state, whilst the second method is more flexible but less accurate. RAO-based predictions are calculated assuming a linear model of ship motions in waves. RAO functions are usually evaluated by means of tests in regular waves for a limited number of frequencies and a constant wave amplitude. This approach is time-consuming and the discrete form of the RAO functions obtained for a limited number of frequencies may lead to discrepancies in the prediction of seakeeping and often does not allow the actual amplitude of the response in resonant frequency to be determined. Another challenge is the appropriate selection of wave amplitude for tests due to the considerable influence of viscous damping on roll response in irregular sea waves. There are alternative methods for the experimental determination of RAO functions and one of them is presented in this study. The presented approach allows RAO functions to be evaluated in one run by the generation of irregular waves characterised by a white or coloured noise spectrum. This method reduces the experiment duration, with almost continuous RAO characteristics obtained. The flat (white noise) and linear (coloured noise) wave spectral energy characteristics are considered in the experiment and the obtained predictions are compared with the results of accurate measurements in irregular waves.
Numerical Study on the Optimization of Hydrodynamic Performance of Oscillating Buoy Wave Energy Converter
Authors: Lai Wenbin , Xie Yonghe , Li Detang
Published: May 2021

The oscillating buoy wave energy converter (OBWEC) captures wave energy through the undulating movement of the buoy in the waves. In the process of capturing wave energy, the hydrodynamic performance of the buoy plays an important role. This paper designed the “Haida No. 1” OBWEC, in which the buoy adopts a form of swinging motion. In order to further improve the hydrodynamic performance of the buoy, a 2D numerical wave tank (NWT) model is established using ADINA software based on the working principle of the device. According to the motion equation of the buoy in the waves, the influence of the buoy shape, arm length, tilt angle, buoy draft, buoy width, wave height and Power Take-off (PTO) damping on the hydrodynamic performance of the buoy is studied. Finally, a series of physical experiments are performed on the device in a laboratory pool. The experimental results verify the consistency of the numerical results. The research results indicate that the energy conversion efficiency of the device can be improved by optimizing the hydrodynamic performance of the buoy. However, the absorption efficiency of a single buoy for wave energy is limited, so it is very difficult to achieve full absorption of wave energy.
Simulations and Tests of Composite Marine Structures Under Low-Velocity Impact
Authors: Zhu Zhaoyi , Li Xiaowen , Chen Qinglin , Cai Yingqiang , Xiong Yunfeng
Published: May 2021

Due to their excellent performance, composite materials are increasingly used in the marine field. It is of great importance to study the low-velocity impact performance of composite laminates to ensure the operational safety of composite ship structures. Herein, low-velocity drop-weight impact tests were carried out on 12 types of GRP laminates with different layup forms. The impact-induced mechanical response characteristics of the GRP laminates were obtained. Based on the damage model and stiffness degradation criterion of the composite laminates, a low-velocity impact simulation model was proposed by writing a VUMAT subroutine and using the 3D Hashin failure criterion and the cohesive zone model. The fibre failure, matrix failure and interlaminar failure of the composite structures could be determined by this model. The predicted mechanical behaviours of the composite laminates with different layup forms were verified through comparisons with the impact test results, which revealed that the simulation model can well characterise the low-velocity impact process of the composite laminates. According to the damage morphologies of the impact and back sides, the influence of the different layup forms on the low-velocity impact damage of the GRP laminates was summarised. The layup form had great effects on the damage of the composite laminates. Especially, the outer 2‒3 layers play a major role in the damage of the impact and the back side. For the same impact energy, the damage areas are larger for the back side than for the impact side, and there is a corresponding layup form to minimise the damage area. Through analyses of the time response relationships of impact force, impactor displacement, rebound velocity and absorbed energy, a better layup form of GRP laminates was obtained. Among the 12 plates, the maximum impact force, absorbed energy and damage area of the plate P4 are the smallest, and it has better impact resistance than the others, and can be more in line with the requirements of composite ships. It is beneficial to study the low-velocity impact performance of composite ship structures.
Hydrodynamic State of Art Review: Rotor – Stator Marine Propulsor Systems Design
Authors: Król Przemysław
Published: May 2021

The paper covers the important topic of rotor–stator propulsor system design and operation. For the stand-alone marine screw propeller, both the design criteria for loading distribution and the theoretical efficiency limits are well described in the basic literature. This is in contrast to the combined propulsor system like a propeller cooperating with a pre-swirl device. The paper describes the current state of the art, summarising results obtained by various researchers by installing energy-saving devices on particular vessels. The design methods utilised are briefly outlined, with the main characteristics underlined. Rough analysis of the gathered data confirms the expected trend that a higher efficiency gain due to ESD installation is possible for a higher propeller loading.
Modelling Ships Main and Auxiliary Engine Powers with Regression-Based Machine Learning Algorithms
Authors: Okumuş Fatih , Ekmekçioğlu Araks , Kara Selin Soner
Published: May 2021

Based on data from seven different ship types, this paper provides mathematical relationships that allow us to estimate the main and auxiliary engine power of new ships. With these mathematical relationships we can estimate the power of the engine based on the ship’s length (L), gross tonnage (GT) and age. We developed these approaches using simple linear regression, polynomial regression, K-nearest neighbours (KNN) regression and gradient boosting machine (GBM) regression algorithms. The relationships presented here have a practical application: during the pre-parametric design of new ships, our mathematical relationships can be used to estimate the power of the engines so that more environmentally friendly ships may be built. In addition, with the machine learning methodology, the prediction of the main engine (ME) and auxiliary engine (AE) powers used in the numerical calculation of ship-based emissions provides data for researchers working on emission calculations. We conclude that the GBM regression algorithm provides more accurate solutions to estimate the main and auxiliary engine power of a ship than other algorithms used in the study.
A Comparative Life Cycle Assessment of Marine Desox Systems
Authors: Cui Mengqi , Lu Yingwei , He Jiahao , Ji Lei , Wang Hui , Liu Shaojun
Published: May 2021

With new sulphur oxides emission limits carried out in 2020, multiple desulphurisation methods have been proposed. The main desulphurisation scrubber systems were chosen and investigated using life cycle assessment. The whole system life is divided into the construction and operational phases. Three different systems classified by desulphurisers, namely, seawater, NaOH, and Mg-based systems, were modelled in GaBi software. Moreover, environmental, economic and energy aspects (3E model) were introduced for further analysis. Through this study, some conclusions have been drawn. As for the environmental aspect, the seawater system has the most pleasing performance since the primary emissions come from 1.24E+03 kg CO2 and 1.48E+01 kg chloride. The NaOH system causes 1000 times more emissions than the seawater. The Mg-based system has less pollution than the NaOH system, with 5.86E+06kg CO2 and 3.86E+03 kg chloride. The economic aspect is divided into capital expenditure (CapEx) and operational expenditure (OpEx) to estimate disbursement. The seawater system also has the most favourable cost appearance, which takes 1.7 million dollars without extra desulphuriser expenses, based on 10MW engine flue gas treatment. The next is the Mg-based system, which cost 2 million dollars in CapEx and $ 1200/year in OpEx for the desulphuriser. NaOH uses about 2.5 million dollars for construction and $ 30000/year in desulphuriser. As for the energy aspect, the seawater and Mg-based systems use less non-renewable energy than the NaOH system in the construction phase. In conclusion, the seawater system shows the best performance and could be an alternative in SOx control technologies. This study sheds light on the comprehensive evaluation of marine environmental protection technologies for further optimisation.
The Matter of Decision-Making Control Over Operation Processes of Marine Power Plant Systems with the Use of their Models in the form of Semi-Markov Decision-Making Processes
Authors: Girtler Jerzy , Rudnicki Jacek
Published: May 2021

The article presents the possibility to control the real operation process of an arbitrary device installed in the marine power plant based on the four-state semi-Markov process, being the model of the process, which describes the transition process of operational states of the device (ek, k = 1, 2, 3, 4), and the transition process of its technical states (sl, l = 1, 2, 3). The operational states ek (k = 1, 2, 3, 4) have the following interpretation: e1 – active operation state resulting from the task performed by the device, e2 – state of ready-to-operate stop of the device, e3 – state of planned preventive service of the device, e4 – state of unplanned service of the device, forced by its damage. Whereas the interpretation of the technical states sl (l = 1, 2, 3) is as follows: s1 – state of full serviceability of the device, s2 – state of partial serviceability of the device, and s3 – state of unserviceability of the device. All these states are precisely defined for the ship main engine (SG). A hypothesis is proposed which justifies the use of this model to examine real state transitions in marine power plant device operation processes. The article shows the possibility to make operating decisions ensuring a rational course of the device operation process when the proposed model of this process and the dynamic programming method based on the Bellman’s principle of optimality are applied. The optimisation criterion adopted when making operating decisions is the expected profit to be gained as a result of functioning of the device in the time interval [τ0, τm], being the sum of the expected profit gained in interval [τ0, τ1] and to be gained in interval [τ1, τm].
Finite Element Fatigue Analysis of Unsupported Crane
Authors: Buczkowski Ryszard , Żyliński Bartłomiej
Published: May 2021

The presented strength and fatigue calculations refer to an unsupported deck crane and its three distinct parts: housing, jib and column. Static loads applied to the structure were due to the crane’s own weight and a maximum working load, corresponding to a maximum lifting capacity at a maximum outreach of the crane. The numerical analysis was aimed at determining the thickness of the skin plating of the column and the number, shape and distribution of stiffeners in the column, housing and jib, ensuring that the crane yields correct strength and fatigue parameters. During the process of designing marine structures, the standard numerical analysis is, in many cases, limited to calculations in the basic strength range. Even when using numerical methods of analysis, complex strength and fatigue calculations are often not performed. The modern numerical analysis chain for marine structures should concentrate not only on strength analysis, but should take a further step, which encompasses fatigue analysis. The article presents a new outlook on design methods, which should be the entry point to the design of marine structures. Based on the acquired number of cycles of fatigue life, it is possible to estimate, with a sufficient degree of accuracy, the practical service life of a structure. To solve the problem, the authors used the finite element analysis software ABAQUS supported by the fe-safe system.
Computational Intelligence in Marine Control Engineering Education
Authors: Lisowski Józef
Published: May 2021

This paper presents a new approach to the existing training of marine control engineering professionals using artificial intelligence. We use optimisation strategies, neural networks and game theory to support optimal, safe ship control by applying the latest scientific achievements to the current process of educating students as future marine officers. Recent advancements in shipbuilding, equipment for robotised ships, the high quality of shipboard game plans, the cost of overhauling, dependability, the fixing of the shipboard equipment and the requesting of the safe shipping and environmental protection, requires constant information on recent equipment and programming for computational intelligence by marine officers. We carry out an analysis to determine which methods of artificial intelligence can allow us to eliminate human subjectivity and uncertainty from real navigational situations involving manoeuvring decisions made by marine officers. Trainees learn by using computer simulation methods to calculate the optimal safe traverse of the ship in the event of a possible collision with other ships, which are mapped using neural networks that take into consideration the subjectivity of the navigator. The game-optimal safe trajectory for the ship also considers the uncertainty in the navigational situation, which is measured in terms of the risk of collision. The use of artificial intelligence methods in the final stage of training on ship automation can improve the practical education of marine officers and allow for safer and more effective ship operation.
Management of epistaxis during COVID-19 pandemic
Authors: Mishra Rahul , Sahoo Anjan Kumar , Gosain Priyanka
Published: May 2021

Epistaxis represents a commonly encountered manifestation in the ENT Emergency Department. Healthcare providers working in the ENT Emergency Department are at high risk of COVID-19 infection both because of the high viral load in the upper airways and because of the asymptomatic presentation of COVID-19 disease. Special focus is needed for managing the balance between appropriate patient care and ensuring the safety of healthcare workers. Adequate preparation and modification of the procedures for bleeding control to minimize risk of spread is necessary. While managing, attention should be kept on less invasive methods with avoidance of aerosol-generating activities. Nonetheless, proper use and disposal of personal protective equipment is of utmost importance in stopping the spread of COVID-19.
Factors associated with survival in diabetic patients with rhino-orbito-cerebral mucormycosis
Authors: Martínez Mario Andrés Sepúlveda , Lugo-Machado Juan Antonio , Canché-Martín Edwin , Sainz-Fuentes Noemí , Reina-Loaiza Roberto , Rodríguez-Quintana Said , Espinoza Alfonso Rubio
Published: May 2021

BACKGROUND. Mucormycosis is an emerging angioinvasive, potentially fatal infection caused by the ubiquitous filamentous fungi of the order Mucorales of the class Phycomycetes. They occur particularly in metabolically decompensated diabetic patients.

OBJECTIVE. To evaluate the factors associated with survival in a group of diabetic patients with rhino-orbito-cerebral mucormycosis.

MATERIAL AND METHODS. A case-control study of a series of cases from January 2013 to May 2020 was designed. Patients with diabetes mellitus and a diagnosis of rhino-orbito-cerebral mucormycosis were included. The clinical findings were considered, as well as age, gender, laboratory and radiological results, and mortality. For the statistical analysis, we used descriptive statistics, Mann Whitney U test. We considered a p-value equal to or less than 0.05 to indicate a statistically significant association or difference. Likewise, the odds ratio was used to determine the relative risk.

RESULTS. 19 cases were included, with an average age of 60.8 years and female gender predominance. In 100% of the cases, nonseptate hyphae were identified in histopathological studies. We had a mortality of 7 (36.8%), where the rhino-orbital complications were the most frequent. The findings of CRP ≤23.1mm/L, an absolute neutrophil count ≥13.2 x1000 /µl and absence of bone erosion in the simple tomography, the rhino-orbital stage, could be related to greater survival.

CONCLUSION. Our series presented mortality close to 40%. Age <64 years, CRP ≤23.1mm/L, absolute neutrophil count ≥13.2 x1000 /µl and absence of bone erosion in the simple tomography, rhino-orbital stage were associated with a better survival in our series.