bluuebunny/crossref_metadata_2025 huggingface dataset:
Medical Students’ Perception of the Research Curriculum and Activating Factors on Research during Medical School
Authors: Kim Insook , Yang Eunbae
Published: September 2015

Including the research in the medical curriculum is regarded as an important issue for medical education. Research experience at medical school has a positive impact on students and it motivates them to undertake further research in the future. The purpose of this study is to explore the factors to activate the research of medical school students. We investigated students perception of the research curriculum in medical school. The survey for this study was conducted among 41 targeted medical school students from across the Republic of Korea. A total of 370 students from 26 medical schools responded. Benefits through research activities were to study about the areas of interest, as researchers had the opportunity to interact with professors and career. Students, furthermore, had difficulties in research due to data collection, the lack of research space and research funding. Requirements to activate the research were the time to participate in research activities, opening regular research courses, preparation of practical research program and motivation for such research. The medical school would need to improve the medical curriculum through the analysis of the environment and situation the school is facing based upon the in-depth analysis results of what the medical school is pursuing through the research activities, what the students want, what the potential difficulties are, and what the requirements are to improve the research curriculum.
The Effect of a Clinical Training Program for Capacity Building of Medical Doctors in a Developing Country
Authors: Yoon Hyun Bae , Shin Jwa-Seop , Lee Seung-Hee , Kim Do-Hwan , Kim Eun Jung , Cho Kyehyeon , Hwang Jinyoung
Published: September 2015

Mongolia is suffering from the inadequate capacity of medical doctors due to a poor education and training system. The purpose of this article is to evaluate the effect of a clinical training program for capacity building of medical doctors in Mongolia, and to suggest an effective model for continuing professional development in developing countries. Based on the results of a needs assessment, Korean and Mongolian medical experts developed a clinical training program and trained the trainers on 32 topics regarding major clinical problems in 6 specialties, including cardiology, endocrinology, pediatrics, obstetrics and gynecology, neurology, and emergency medicine. Surveillance survey and pre/post-test were used on every topic to evaluate the satisfaction and achievement, respectively, of the trainees. Six months after the clinical training program, we interviewed a sample of medical professionals to evaluate the change and impact. A total of 612 (person-year) medical doctors participated in the training, and the average score for satisfaction was 7.69 out of 8. The average score of the pre-test was 46.9 out of 100, while the post-test was 82.4. After the training, the medical doctors were applying their new knowledge and skills to their practice, and using the materials as guidelines, which improved their practice and increased patient satisfaction. They also started their own training program and adopted new equipment at their hospitals. The satisfaction and achievement of the trainees were very high, and there was significant change in the medical practice, education system, and infrastructure after the training program. This training program can be an effective model for capacity building of medical doctors in developing countries.
Poroelastic and Poroplastic Modeling of Hydraulic Fracturing in Brittle and Ductile Formations
Authors: Wang HanYi , Marongiu-Porcu Matteo , Economides Michael J.
Published: September 2015

The prevailing approach for hydraulic-fracture modeling relies on linear-elastic fracture mechanics (LEFM). Generally, LEFM that uses stress-intensity factor at the fracture tip gives reasonable predictions for hard-rock hydraulic-fracturing processes, but often fails to give accurate predictions of fracture geometry and propagation pressure in formations that can undergo plastic failures, such as poorly consolidated/unconsolidated sands and ductile shales. This is because the fracture-process zone ahead of the crack tip, elasto-plastic material behavior, and strong coupling between flow and stress cannot be neglected in these formations. Recent laboratory testing has revealed that in many cases, fracture-propagation conditions cannot be described by traditional LEFM models. Rather, fractures develop in cohesive zones. In this study, we developed a fully coupled poro-elasto-plastic hydraulic-fracturing model by combining the cohesive-zone method with the Mohr-Coulomb theory of plasticity, which not only can model fracture initiation and growth while considering process-zone effects, but also can capture the effects of plastic deformation in the bulk formation. The impact of the formation plastic properties on the fracture process is investigated, and the results are compared with existing models. In addition, the effects of different parameters on fracture propagation in ductile formations are also investigated through parametric study. The results indicate that plastic and highly deforming formations exhibit greater breakdown and propagation pressure. The more plastic the formation (lower cohesion strength), the higher the net pressure required to propagate the fracture. Also, lower cohesion strength leads to shorter and wider fracture geometry. The effect of formation plasticity on a hydraulic fracture is mostly controlled by initial stress contrast, cohesion strength of formation rock, and pore pressure. We also found that altering the effective fracture toughness can only partially mimic the consequences of increased toughness ahead of the fracture tip in ductile formations, but it fails to capture the effect of shear failure within the entire affected area, which can lead to underestimating the fracture width and overestimating the fracture length. For a more-accurate modeling of fracturing in ductile formations, the entire plastic-deformation region induced by the propagating fracture should be considered, especially when shear-failure areas are large.
Proteomics reliability for micropollutants degradation insight into activated sludge systems
Authors: Buttiglieri Gianluigi , Collado Neus , Casas Nuria , Comas Joaquim , Rodriguez-Roda Ignasi
Published: September 2015

Little information is available on pharmaceutical trace compounds degradation pathways in wastewater. The potential of the proteomics approach has been evaluated to extract information on activated sludge microbial metabolism in degrading a trace concentration of a pharmaceutical compound (ibuprofen). Ibuprofen is one of the most consumed pharmaceuticals, measured in wastewater at very high concentrations and, despite its high removal rates, found in different environmental compartments. Aerated and completely mixed activated sludge batch tests were spiked with ibuprofen at 10 and 1,000 μg L−1. Ibuprofen concentrations were determined in the liquid phase: 100% removal was observed and the kinetics were estimated. The solid phase was sampled for proteomics purposes. The first objective was to apply proteomics to evaluate protein profile variations in a complex matrix such as activated sludge. The second objective was to determine, at different ibuprofen concentrations, which proteins followed pre-defined trends. No newly expressed proteins were found. Nonetheless, the obtained results suggest that proteomics itself is a promising methodology to be applied in this field. Statistical and comparative studies analyses provided, in fact, useful information on biological reproducibility and permitted us to detect 62 proteins following coherent and plausible expected trends in terms of presence and intensity change.
Practical aspects of cellular M2M systems design
Authors: Prijic Aneta , Vracar Ljubomir , Vuckovic Dusan , Dankovic Danijel , Prijic Zoran
Published: September 2015

This paper highlights some crucial design challenges of Machine-to-Machine
(M2M) systems. The focus is on the cellular based, wireless wide area network
systems. Design of M2M terminals, used as wireless sensor nodes, is covered
in detail, including the criteria for selecting appropriate core and hard-
ware peripherals. Discussion is extended to modeling and design of terminal?s
embedded software. Communication using framework and backend application
software architectures are explored. Practical examples of the described
design principles are demonstrated.
A note on the proof of Bertrand's theorem
Authors: Jovanovic Vladimir
Published: September 2015

In this paper we fill a common gap in the proof of Bertrand' theorem present
both the in Bertrand's original paper Th?or?me relatif au movement d'un
point attir? vers un centre fixe and in the Arnold's book Mathematical
methods of classical mechanics, by providing missing details which pertain
to the problem of how to single out elastic and gravitational potentials
among the power law ones.
Cenozoic structural and metamorphic evolution and geological map and sections of the NW Indian Himalaya
Authors: Steck Albrecht
Published: September 2015

No abstract
Time-delayed contrast-enhanced MRI improves detection of brain metastases and apparent treatment volumes
Authors: Kushnirsky Marina , Nguyen Vinh , Katz Joel S. , Steinklein Jared , Rosen Lisa , Warshall Craig , Schulder Michael , Knisely Jonathan P. S.
Published: September 2015

OBJECT

Contrast-enhanced MRI is the preeminent diagnostic test for brain metastasis (BM). Detection of BMs for stereotactic radiosurgery (SRS) planning may improve with a time delay following administration of a high-relaxivity agent for 1.5-T and 3-T imaging systems. Metastasis detection with time-delayed MRI was evaluated in this study.

METHODS

Fifty-three volumetric MRI studies from 38 patients undergoing SRS for BMs were evaluated. All studies used 0.1-mmol/kg gadobenate dimeglumine (MultiHance; Bracco Diagnostics) immediately after injection, followed by 2 more axial T1-weighted sequences after 5-minute intervals (final image acquisition commenced 15 minutes after contrast injection). Two studies were motion limited and excluded. Two hundred eighty-seven BMs were identified. The studies were randomized and examined separately by 3 radiologists, who were blinded to the temporal sequence. Each radiologist recorded the number of BMs detected per scan. A Wilcoxon signed-rank test compared BM numbers between scans. One radiologist determined the scan on which BMs were best defined. All confirmed, visible tumors were contoured using iPlan RT treatment planning software on each of the 3 MRI data sets. A linear mixed model was used to analyze volume changes.

RESULTS

The interclass correlations for Scans 1, 2, and 3 were 0.7392, 0.7951, and 0.7290, respectively, demonstrating excellent interrater reliability. At least 1 new lesion was detected in the second scan as compared with the first in 35.3% of subjects (95% CI 22.4%–49.9%). The increase in BM numbers between Scans 1 and 2 ranged from 1 to 10. At least 1 new lesion was detected in the third scan as compared with the second in 21.6% of subjects (95% CI 11.3%–35.3%). The increase in BM numbers between Scans 2 and 3 ranged from 1 to 9. Between Scans 1 and 3, additional tumors were seen on 43.1% of scans (increase ranged from 1 to 14). The median increase in tumor number for all comparisons was 1. There was a significant increase in number of BMs detected from Scan 1 to Scan 2 (p < 0.0367) and from Scan 1 to Scan 3 (p < 0.0264). In 34 of the 51 subjects (66.7%), the radiologist selected the third scan as the one providing the clearest tumor definition. There was an average 25.4% increase in BM volume between Scans 1 and 2 (p < 0.0001) and a 9% increase in BM volume between Scans 2 and 3 (p = 0.0001).

CONCLUSIONS

In patients who are being prepared for SRS of BMs, delayed MRI after contrast injection revealed more targets that needed treatment. In addition, apparent treatment volumes increased with a time delay. To avoid missing tumors that could be treated at the time of planned SRS and resultant "treatment failures," the authors recommend that postcontrast MR images be acquired between 10 and 15 minutes after injection in patients undergoing SRS for treatment of BMs.
Is the lateral jack-knife position responsible for cases of transient neurapraxia?
Authors: Molinares Diana Margarita , Davis Timothy T. , Fung Daniel A. , Liu John Chung-Liang , Clark Stephen , Daily David , Mok James M.
Published: September 2015

OBJECT

The lateral jack-knife position is often used during transpsoas surgery to improve access to the spine. Postoperative neurological signs and symptoms are very common after such procedures, and the mechanism is not adequately understood. The objective of this study is to assess if the lateral jack-knife position alone can cause neurapraxia. This study compares neurological status at baseline and after positioning in the 25° right lateral jack-knife (RLJK) and the right lateral decubitus (RLD) position.

METHODS

Fifty healthy volunteers, ages 21 to 35, were randomly assigned to one of 2 groups: Group A (RLD) and Group B (RLJK). Motor and sensory testing was performed prior to positioning. Subjects were placed in the RLD or RLJK position, according to group assignment, for 60 minutes. Motor testing was performed immediately after this 60-minute period and again 60 minutes thereafter. Sensory testing was performed immediately after the 60-minute period and every 15 minutes thereafter, for a total of 5 times. Motor testing was performed by a physical therapist who was blinded to group assignment. A follow-up call was made 7 days after the positioning sessions.

RESULTS

Motor deficits were observed in the nondependent lower limb in 100% of the subjects in Group B, and no motor deficits were seen in Group A. Statistically significant differences (p < 0.05) were found between the 2 groups with respect to the performance on the 10-repetition maximum test immediately immediately and 60 minutes after positioning. Subjects in Group B had a 10%–70% (average 34.8%) decrease in knee extension strength and 20%–80% (average 43%) decrease in hip flexion strength in the nondependent limb.

Sensory abnormalities were observed in the nondependent lower limb in 98% of the subjects in Group B. Thirty-six percent of the Group B subjects still exhibited sensory deficits after the 60-minute recovery period. No symptoms were reported by any subject during the follow-up calls 7 days after positioning.

CONCLUSIONS

Twenty-five degrees of right lateral jack-knife positioning for 60 minutes results in neurapraxia of the nondependent lower extremity. Our results support the hypothesis that jack-knife positioning alone can cause postoperative neurological symptoms.
FRAMEWORKS TO IDENTIFY BEST PRACTICES AT THE ORGANIZATION LEVEL: AN ANALYSIS
Authors: Cuentas Gerardo Luís Angulo , Pico Jaime Alberto Camacho , Arias Astrid Jaime
Published: September 2015

This paper identifies and analyzes the existing frameworks for supporting the identification and classification of best practices at an organization level. The major contribution of this paper is the proposition and application of three criteria for analyzing, comparing and classifying the four identified frameworks. The first criterion is based on structural complexity, facilitates defining the scope of initiatives to identify best practices. The second one, based on the framework orientation, permits choosing a framework depending of the type of studied processes. While the third criterion based on organizational levels, permits comparing and classifying the frameworks in terms of the strategic, tactic or operational issues.
INDUSTRY CONCENTRATION AND THE CROSS-SECTION OF STOCK RETURNS: EVIDENCE FROM THE UK
Authors: Hashem Nawar , Su Larry
Published: September 2015

In this paper, we examine the relationship between market structure and ex- pected stock returns in the London Stock Exchange during 1985 and 2010. Using Fama- MacBeth regressions, we find that industry concentration is negatively related to average stock returns, even after controlling for beta, size, book-to-market equity, momentum, and leverage. In addition, there is a strong evidence of a growth effect. Firms or industry portfolios with smaller book-to-market ratios have significantly higher returns. In contrast, beta is never statistically significant. The above results are robust to firm- and industry- level regressions, and the formation of firms into 100 size-beta portfolios. Our findings indicate that competitive industries earn, on average, higher risk-adjusted returns than concentrated industries. An explanation is that investors in more competitive industries require larger premiums for greater distress risks associated with these industries. Our paper is one of the first to link market competition with the average stock returns in the UK, and contributes to the asset pricing literature by extending the evidence from the US to another important financial market.
DYNAMICS OF ATTACK ACTIONS IN THE MOBBING STRATEGY: THE CASE OF LITHUANIA
Authors: Zukauskas Pranas , Vveinhardt Jolita , Melnikas Borisas , Grančay Martin
Published: September 2015

The purpose of this research is to determine the occurrence and prevalence of different mobbing actions used against a victim in the context of Lithuanian organisations, taking into account the type of professional activity. A questionnaire was created for the purpose of the research. The reliability of the ques- tionnaire is demonstrated using indicators of the methodological quality of characteristics. The research revealed that in mobbing strategies, most bullying behaviour is interrelated and constructs a particular system, which is driven by insulting communication, defama- tion and isolation. The results draw the attention of managers of organisations to the nature of unethical communication and the need to protect dignity and reputation of employees and prevent mobbing and bullying. An original instrument was developed and used to interview mobbing and bullying vic- tims.
Du vin et du haschisch
Authors: Baudelaire Charles
Published: September 2015

L’ivresse est un thème récurrent dans l’œuvre de Charles Baudelaire. L’essai Du vin et du haschisch paraît en 1851. Le poète s’attache à décrire les comportements sociaux des consommateurs. Il y glorifie le vin, qui « rend bon et sociable ». Le haschisch est condamné parce qu’il est « antisocial », « il est fait pour les misérables oisifs ». Contrairement au vin, il n’incite pas à l’action et annihile toute volonté.
Le dictionnaire de théologie catholique et le statut épistémologique de la théologie
Authors: De Franceschi Sylvio Hermann
Published: September 2015

Publié de 1899 à 1950, le Dictionnaire de théologie catholique a longtemps été considéré comme l’incarnation de positions doctrinales conservatrices. À parcourir les articles qui traitent en son sein des domaines et des méthodes de la théologie, comme les articles Fondamentale ou générale (théologie) du chanoine Albert Michel, Lieux théologiques d’Ambroise Gardeil, Salamanque (théologiens de) de Thomas Deman, Thomisme de Réginald Garrigou-Lagrange ou encore Théologie d’Yves Congar, force est de constater que le Dictionnaire de théologie catholique a en réalité activement participé aux grands débats épistémologiques qui ont contribué à renouveler profondément le champ de la théologie catholique contemporaine.
An Intuitive Teleoperation of Industrial Robots
Authors: Bisson Andrea , Michieletto Stefano , Ferrara Valentina , Romanelli Fabrizio , Menegatti Emanuele
Published: September 2015

Teleoperation of manipulator robots with RGB-D sensors is now mainly done using inverse kinematics techniques. In this chapter, we describe an intuitive way to teleoperate an industrial manipulator through vision sensors by directly controlling manipulator joints retargeting specific human motion. In this way the human operator has the full control of robot movements with practically no training, because of the intuitivity of this teleoperation method. The remapping into the robot joints is done by computing angles between vectors built from positions of human joints, tracked by the selected vision sensor. The obtained system is very modular which allows to change either the tracking sensor or the robot model with some small changes. Finally, the developed teleoperation system has been successfully tested on two real Comau robots, revealing to be fast and strongly reliable.
Spiritual Health Identity
Authors: Harris-Smith Y. Joy
Published: September 2015

This chapter aims to identify the ways in which spirituality, religion and the Black Church help to shape a spiritual health identity in a group of Black women by placing their lived experiences at the center of analysis using methods that are epistemologically consistent with how they understand the world. A spiritual health identity refers to the recognition and consciousness that a healthy spiritual life is essential to one's existence. It effects how they see themselves and their relationships to other people. Black women's ways of knowing are often pushed to the margins and lacking validation in mainstream society. Utilizing a womanist epistemological framework allows Black women to define themselves and lifts up the ways, spaces and places that help them make meaning.
Electronic Patient Records (EPR), Library Services (LS) and Multidisciplinary Team (MDT) Meetings
Authors: Muhammad Shahid , Rigler Malcolm , Adams Meshia
Published: September 2015

Patients with Long-Term Conditions (LTCs) account for around 50% of General Practitioner (GP) appointments, 64% of outpatient appointments and 70% of hospital bed days. There needs to be a wider access to knowledge and understanding such as directories with information leaflets, documents, books on lifestyle, helpful contacts and sources to information that can support patients and the general public on the most important elements their health. This cannot be achieved just through patients accessing their health records in sole. The objective of this paper is to 1) highlight the importance of integrating General Practice (GP), Electronic Patient Records (EPR) with Library Services (LS) and 2) also explore why it would be advantageous to implement patient-centred Multidisciplinary Team (MDT) meetings in primary care for patients with Long-Term Conditions (LTCs). This article provides a UK glance and how primary care services can be improved, integrating for the better. Having access to Electronic Patient Records (EPR) alone will not help or encourage a patient to gain confidence and/ or understanding especially if patients are overwhelmed by their healthcare choices and Health Literacy (HL) complexities. Patients' whose first language is not English for example, approaching more methods to support HL is/ will be challenging. Library and Health Services partnerships should be initiated to allowing access to wider resources. In addition, patient-centred Multidisciplinary Team (MDT) meetings should be arranged at dedicated time points between a doctor and patient/ carer and these can take place in a private section within library setting involving wider participation in care plans. Given that more patients and the public will have opportunity to access their health records, a “Libraries and Health” partnership can help integrate primary healthcare better thus allowing all to access health-related literature, using books, leaflets and digital media in a comfortable environment in a setting that also has staff that can support with HL and technology. An EPR and MDT initiative should be supported with library and health partnerships; this needs to be encouraged.
The Importance of Raising Chronic Kidney Disease (CKD) Awareness for Young People and Parents
Authors: Muhammad Shahid , Sen Barbara
Published: September 2015

Chronic Kidney Disease (CKD) in young people is complex, with many requiring Renal Replacement Therapy (RRT). Young people may be disenfranchised by perceptions of helplessness and feelings of powerlessness against a backdrop of diminished health, consequently impacting on their capacity for effective coping. Not surprisingly, young people and parents/ guardians seek online support through social media which offers advantages over standard forms of engagement/ education. The claim here is that future clinicians are unable to best practice unless they get more involved in patient-led initiatives and better appreciate how young people with CKD and their parents use the internet/ social media as an effective learning resource. Social media can positively influence young people, parents/ guardians to gather resources, supporting them to develop self-care and enhance shared-decision-making, empowering them to adopt coping strategies. Health professionals should have an understanding of what resources are available to young people and parents/ guardians.
Cracking in Brittle Coatings during Nanoindentation
Authors: Lofaj František , Németh Dušan , Podoba Rudolf , Novák Michal
Published: September 2015

The FIB/SEM investigations of the microstructure changes in the hard brittle W-C based coating deposited on softer steel substrate after nanoindentation tests revealed that a set of approximately equidistant circular cracks forms in the coating in a sink-in zone around the indent and single cracks appear under the indenter tip. Finite element modeling (FEM) indicated development and concentration of the highest principal tensile stresses in the sink-in zone and in the zone below the indenter, which are considered to be the reason for the experimentally observed cracking. The distance from the indenter tip to the first circular crack combined with the calibration curve obtained from the FEM of the location of tensile stress maxima in sink-in zone can be used as a simple method for the determination of the strength of the studied coatings.
High Temperature Resistance of Selected HVOF Coatings
Authors: Houdková Šárka , Černý Jan , Pala Zdeněk , Haušild Petr
Published: September 2015

The HVOF (high velocity oxygen fuel) thermal spraying technology is widely used for creation of coatings notable for their resistance against various kinds of loading. Depending on the sprayed material, the coatings suitable for high temperature applications can be sprayed as well. The coatings, based on CrC or Co/Ni alloys, offer the advantageous combination of high temperature oxidation resistance and the wear resistance. In the paper, the attention is paid to the evaluation of the influence of the high temperature on the coatings microstructure and mechanical properties, namely hardness. The stability of the hardness values in respect to the time of the high temperature exposure is presented and related to the phase composition changes.
Influence of Hot Corrosion on Local Mechanical Properties of HVOF Sprayed Coating Based on NiCrBSi Alloy
Authors: Schubert Jan , Česánek Zdeněk , Bláhová Olga
Published: September 2015

Ongoing increase in demands on efficiency of power plants and other facilities leads to increased interest of new progressive materials and technologies. One of the modern methods which lead to enhancement of surface properties is application of coatings on surface of components composed of less quality materials. Commonly used methods protecting components are based on some form of heat treatment. The current pressure on increasing operating temperatures for enhanced performance of steam turbines caused elevation of operating temperature at limit of the applicability of commonly used protections. From this reasons the demand for using an alternative technologies which would provide such a desired protection rises rapidly. One of the key areas of protection in such environment is protection against hot temperature corrosion. Possible solution can be found in application of coatings based on alloys and cermets prepared by HVOF technology. This paper examines local mechanical and microstructural properties of NiCrBSi coating after exposition to extremely severe hot corrosion environment. Furthermore, the nanoindentation measurements of NiCrBSi coating were performed before and after the corrosion test. In this case the mixture of salts composed from 59% Na2(SO)4 with 34.5% KCl and 6.5% NaCl was used. Temperature of test was set on 525°C and 575°C. Duration of exposition to hot corrosion environment was 168 hours in autoclave.
Mapping of Local Changes of Mechanical Properties in Trabecular Interconnections
Authors: Kytýř Daniel , Fenclová Nela , Koudelka Petr , Doktor Tomáš , Šepitka Josef , Lukeš Jaroslav
Published: September 2015

This paper deals with evaluation of mechanical properties of human trabeculae in the interconnection area. Local changes in the trabecular connections were evaluated using both quasi-static nanoindenation and modulus mapping technique. Connecting point of two trabeculae was revealed by precise grinding and polishing. A rectangular region in the interconnection was selected and inspected by modulus mapping procedure. Moreover several quasi-static indentation measurements using cube-corner indenter were performed along distinct lamellae. The obtained elastic properties were then compared with the values of the rod-like trabeculae. The comparison does not indicate significant differences in elastic properties between the trabecular rods and interconnections.
Effect of High Doses Beta Irradiation on the Micromechanical Properties of Surface Layer of Glass-Filled Polypropylene
Authors: Manas David , Manas Miroslav , Mizera Ales , Stanek Michal , Bednarik Martin , Ovsik Martin , Stoklasek Pavel
Published: September 2015

The presented article deals with the research of micro-mechanical properties in the surface layer of modified Polypropylene filled by 25% of glass fibers. These micro-mechanical properties were measured by the Depth Sensing Indentation - DSI method on samples which were non-irradiated and irradiated by different doses of the β - radiation. Radiation doses used were 0, 66 and 99 kGy for filled Polypropylene with the 6% cross-linking agent (triallyl isocyanurate). The change of micromechanical properties is greatly manifested mainly in the surface layer of the modified polypropylene where a significant growth of microhardness values can be observed.
The Use of a 3D Scanner for Evaluating the Morphology of a Sandblasted Concrete Surface
Authors: Czarnecki Sławomir , Hoła Jerzy , Sadowski Łukasz
Published: September 2015

The possibility of the non-destructive testing of concrete surface morphology by means of a new-generation 3D laser scanner is presented. The test results for a reference concrete substrate surface and a sandblasted concrete substrate surface are reported. The effect of sandblasting on the morphology of the concrete surfaces of the substrates is highlighted. The results are presented as three-dimensional images and the values of the morphology parameters are compared in a table.
Fatigue Strength and Damage Mechanisms of Laser Welded Structural Carbon Steel Sheets
Authors: Černý Ivo , Sís Jiří
Published: September 2015

Laser welding is one of advanced and promising joining technologies of metallic materials, characteristic by numerous advantages in comparison with conventional welding processes. The technology still can be considered as fairly new and so, investigations are needed to reach optimum properties of welds in specific application cases, depending on welding parameters. Certification welding procedures usually require to demonstrate sufficient microstructure, mechanical, impact loading and other characteristics, but not fatigue resistance, which is essential for welded dynamically loaded structures. The paper contains results of fatigue resistance investigation of laser welded 10 mm thick sheets of a carbon structural S 355 steel. High cycle fatigue tests were performed after optimizing laser welding parameters. Resulting endurance limit of the welds and heat affected zone was higher than that of basic material. However, high scatter of results and different damage mechanisms were shown for different load amplitudes. The results are discussed on the basis of fractographical analyses, which provided some quite interesting details about crack initiation mechanisms.
Mechanical Joining of Various Materials by Clinching Method
Authors: Kaščák Ľuboš , Spišák Emil , Mucha Jacek
Published: September 2015

Clinching is a simple, cheap and efficient method of joining that enables to join two or more sheets without any additional elements such as rivets, bolts or nuts. In addition, clinching does not require a surface preparation e.g. drilling (riveting), cleaning and roughening of the surface (adhesive boding) and other types of surface preparations (arc welding). Clinching is utilized in a wide range of applications and can be applied to different materials such as low carbon steel sheets, high-strength steel sheets, aluminium alloys, magnesium alloys. The paper presents the results of evaluation of clinched joint properties. The advanced high-strength steel sheet DP600 in combination with the drawing grade steel sheets DC06, DX51D+Z and high-strength low alloy steel sheet H220PD were used for experiments. The influence of position of the sheets relative to the punch and die of the tool on the carrying capacities of the clinched joints was observed as well. The tension test and microhardness test were used for the evaluation of clinched joint properties.
Nanoindentation Study of the Influence of the Loading Rate on the Deformation of Metallic Glasses
Authors: Hurakova Maria , Csach Kornel , Juríková Alena , Miškuf Jozef , Demcak Stefan , Ocelík Václav , de Hosson Jeff T.M.
Published: September 2015

Nanoindentation experiments at the loading rates from 0.05 to 100 mN.s-1 on the amorphous FeNiB alloy were executed. We found that the serrations in the load-displacement (P-h) curve are more pronounced at lower loading rates and gradually disappear upon increasing loading rate. We have estimated the contribution of the inhomogeneous plastic deformation from pop-in events on the P-h curves. The pop-in population was compared with the morphology of indents.
Comparison of the Results of Creep and Micro-Indentation Creep to Irradiated HDPE
Authors: Reznicek Martin , Ovsik Martin , Bednarik Martin , Kratky Petr , Manas David
Published: September 2015

The main goal of this paper is to compare measurements of creep behavior of Crosslinking polymer materials. Creep properties have been measured by two methods, first is micro-indentation with Depth Sensing Indention (DSI) and the second method is long-term creep test in room temperature. By using of these principally different methods can be better analyzed the influence of radiation netting, and therefore better suggest an appropriate dose of radiation with respect to use of polymer material in practice. The evaluation criteria for DSI test is index CIT [%]. The evaluation criteria for the standard creep test is value of average elongation at the end of the test. Comparison of these two values shows slight influence of radiation dose with using the standard creep test instead of using micro-indentation creep test, which shows very slight influence of radiation dose on material.
Experimental Verification of the Effective Thickness of Laminated Glass
Authors: Bouška Petr , Špaček Miroslav , Crhan Drahomír , Bittner Tomáš , Vokáč Miroslav
Published: September 2015

Properties of laminated glass comprising two or more sheets of glass are greatly affected by the composite action of these panes which is influenced by material properties of used interlayer. Generally plastic foil or cast resin is used as the interlayer in lamination process. Laminated glass has been experimentally investigated in the laboratory condition in a four-point bending test on several kinds of interlayers in combination with variable thickness of the annealed glass. This paper establishes the so-called effective bending thickness according to standard method and presents comparisons with experimentally determined values.
Evaluation of Material Parameters of Multiphase Materials Using Drift Distortion Corrected SEM Imaging
Authors: Koudelková Veronika , Koudelka Petr , Kytýř Daniel , Doktor Tomáš , Valach Jaroslav
Published: September 2015

In contrast to imaging in visible spectrum temporally-varying distortion (drift distortion) caused by positional errors of electron beam during the scanning process occurs in SEM devices. This effect is always present in the data from SEM and its magnitude depends on acquisition time, magnification and conductivity of the sample (where lower conductivity causes higher drift distortion). In this paper 2D digital image correlation based on Lucas-Kanade algorithm was used to assess drift distortion characteristics of MIRA II LMU SEM device during imaging of materials with different conductivity and microstructural properties. Using the DIC technique deformations in the micrographs were evaluated and tool for correction of positional errors was developed. As shown on a set of selected multiphase mixtures this tool enables qualitative backscattered electron analysis independently on the material type and imaging parameters including acquisition time. This enables reliable evaluation of material parameters that have influence on effective mechanical properties.
Relationship between Indenter Calibration and Measured Mechanical Properties of Elastic-Plastic Materials
Authors: Čech Jaroslav , Haušild Petr , Nohava Jiri
Published: September 2015

Calibration of Berkovich indenter area function was performed on materials with different elastic-plastic behavior resulting in pile-up and sink-in, respectively. Experimentally obtained results were compared with the results obtained by the application of theoretical area function. The values of Young’s modulus and hardness were significantly affected by the calibration function used. Since the effects of pile-up and sink-in are already included in the used area function, this simple method can lead to more accurate results of Young’s modulus and hardness measurements.
Investigation of Indentation Parameters Near the Interface between Two Materials
Authors: Kocmanová Lenka , Haušild Petr , Materna Aleš , Matějíček Jiří
Published: September 2015

The paper participates in a development of composites. A composite tungsten-steel is studied as materials suitable for a first wall of tokamak, a composite FeAl + Al2O3 is a possible material for fourth generation of a nuclear power plant and a composite Al2O3 + YSZ is a potential implant material. The focus of our study is change of material properties near the interface and a determination of area size which is influenced by the adjacent material. Material properties are investigated by nanoindentation. The task is simulated using finite element method. Simulated specimen is composed of a tungsten part and a steel part. The sharp boundary between materials is a plane which is located parallel to the loading force direction. Elastic modulus is determined in dependence of a distance between the interface and a tip of the indenter. The simulated results are verified experimentally.
Combined Indentation Testing of Spark Plasma Sintered Steels
Authors: Musalek Radek , Tesar Tomas , Strasky Josef , Cech Jaroslav
Published: September 2015

Mechanical properties of two stainless steels (AISI 316L and AISI 410) processed by spark plasma sintering (SPS) were evaluated by four different types of indentation-based tests: hardness mapping, evaluation of indentation stress-strain curves, instrumented indentation and bonded-interface technique. Obtained results showed that the used combination of relatively simple experiments may provide a deeper understanding of mechanical behavior of materials prepared by SPS.
Fracture Process in a Fine-Grained Cement-Based Composite Monitored with Nanoindentation and Acoustic Emission
Authors: Němeček Jiří , Keršner Zbyněk , Schmid Pavel , Havlíková Ivana , Šimonová Hana , Topolář Libor , Veselý Václav , Rovnaník Pavel
Published: September 2015

The contribution is devoted to investigation of the fracture process zone (FPZ) in a fine-grained cement-based composite made from hydrated Portland cement. Particularly, experimental investigations and description of the stable crack propagation using fracture mechanics model are conducted. Three-point bending tests on small composite beams with a central edge notch were performed. The damage due to fracture was monitored by means of nanoindentation performed around the macroscopically observable crack. Acoustic emission events were recorded during the three-point bending test and correlated with load–displacement data. The beneficial effect on the fracture resistance of fine-grained mortar specimens compared to plain cement pastes was quantified.
Influence of Microstructure on Tribological Properties and Nanohardness of Silicon Carbide Ceramics
Authors: Kovalčíková Alexandra , Balko Ján , Dusza Ján
Published: September 2015

The influence of microstructural variations on the tribological properties and nanohardness of liquid phase sintered silicon carbide (LPS SiC) has been observed. In order to modify the microstructures samples were further heat treated at 1650°C and 1850°C for 5 hours to promote grain growth. The depth-sensing indentation tests of SiC materials were performed at several peak loads in the range 10-400 mN. The pin-on-flat dry sliding friction and wear experiments have been made on SiC ceramics in contact with Al2O3 ceramic ball at 10-50 N loads in an ambient environment. The nanohardness of samples with plate-like microstructure was about 34 GPa i.e. 3 GPa higher than nanohardness of SiC with fine globular microstructure. The SiC materials with coarser plate-like microstructure had similar COF (0.4-0.55) and better wear resistance (one order of magnitude at normal forces 10-20N) than SiC materials with fine globular microstructure.
Modelling and Analysis of Reinforced Concrete Beams
Authors: Sucharda Oldrich , Kubosek Jan
Published: September 2015

The goal of the paper is to model and evaluate the total load capacity of the reinforced concrete beams. A non-linear analysis and finite element method were used for that purpose. The model consists of 3D finite elements. The constitutive model of concrete for the non-linear analysis is based on a fracture-plastic theory. The input parameters are the data obtained in previous tests which included both standard tests and additional tests of the testing bodies. There is no shear reinforcement in the beams. The non-linear calculations were carried out for several variants. The study takes into considerations the influence of concrete properties as well as the size of the finite elements.
Study of the Mechanical Properties of Single-Layered and Bilayered CoCrFeSi Ribbons Using Quasistatic and Dynamic Nanoindentation Tests
Authors: Buršík Jiří , Buršíková Vilma , Jirásková Yvonna
Published: September 2015

In this work we have studied local mechanical properties of CoCrFeSiB ribbons prepared by planar flow casting (PFC). Recently improved PFC technology enabled us to use two melts simultaneously and to prepare a bilayered Co69Fe2Cr7Si8B14/Co59Fe12Cr7Si8B14 ribbon with a good homogeneity of the layers and well defined interface. Single-layered ribbons of the two compositions above were prepared as well. The microstructure and the composition profiles were studied by means of analytical electron microscopy. Nanoindentation tests were carried out on the cross sections of the bilayered ribbon as well as of single-layered ribbons. The in-situ SPM imaging was used in order to achieve nanometer precision positioning of the indents and to get information about the surface topography before and after the tests.
Vrede as ’n onontginde navorsingstema in die Nuwe-Testamentiese Wetenskap
Authors: De Villiers Pieter G.R.
Published: September 2015

Peace as research theme in New Testament studies. This research article investigates peace as an underdeveloped theme in New Testament studies. Its first part documents this situation by analysing the role of the Bible and biblical research in the extensive social, theological and ecclesiastical discourse on war, violence and peace. In following parts the article investigates some recent literature in New Testament studies on peace and evaluates its place in the discipline as representing a reversal of the limited attention to peace and as illustration of the need for more research. In a fourth part the reasons why peace as a theme is relatively underdeveloped, are spelled out, whilst a fifth section investigates the need for and challenges to exploring peace adequately within New Testament Studies.
A logistics sector’s perspective of factors and risks within the business environment that influence supply chains’ effectiveness: An explorative mixed method study
Authors: Badenhorst-Weiss Johanna A. , Waugh Beverley J.
Published: September 2015

Background: Supply chains in South Africa operate in a challenging business environment. This environment influences the efficiency and effectiveness of South African businesses and supply chains. These factors further influence the competitiveness of products produced in the country, the economic growth and development of South Africa.Objectives: The purpose of this study was two-fold: Firstly, to obtain insight into the main business environment risks and other factors, from a logistics perspective; and secondly, to demonstrate the use of methodology not often used in logistics research − the sequential mixed method.Method: The explorative study was conducted amongst logistics service providers and cargo owners in 2013 by means of a sequential mixed method study, consisting of a survey to determine the importance of risk factors in the business environment, followed by a qualitative study in the form of a focus group discussion to obtain richer data and insight into these risks and factors. The results of these two methods were integrated with industry literature.Results: It was found that increasing transportation costs, operational management of infrastructure and human resources-related problems pose the biggest challenges in the logistics industry. In addition, it was found that the mixed method research study has application possibilities in logistics research.Conclusion: The factors identified as particularly problematic for the logistics industry, namely ineffective operational management of infrastructure, the general conditions in the labour market and increasing costs (to some extent) are outside the control of individual organisations. However, organisations can control how they react and mitigate these risk factors. It is shown that these factors and risks can change overnight. The use of the explorative mixed method in obtaining qualitative and quantitative inputs and integrating it with existing literature proved to be a workable and usable methodology.