bluuebunny/crossref_metadata_2025 huggingface dataset:
Listening to Alzheimer's
Authors: Beard Renee L. , O'Connor Maureen K.
Published: August 2015

After outlining major trends in the literature base, highlighting the shortcomings, and suggesting future areas of study, this chapter calls for including more sociological analysis, namely attention to social location, in research on the individual's changing perspectives in Alzheimer's Disease (AD), or AD narratives. Rather than assuming that illness experiences can be universalized, variables such as race/ethnicity, marital status, class, gender, religiosity, and age as well as the roles of mass media and medicine, matter deeply in how AD is interpreted and experienced. This chapter proposes that psychosocial studies of the topic need to systematically explore at least five areas: 1) comprehensive illness narratives, including the potential positive aspects, 2) the role of sociodemographic variables, 3) the narrative transformations throughout the illness trajectory, 4) the bioethical implications of diagnosing individuals increasingly earlier, and 5) the impact of institutional forces like mass media and modern medicine on illness narratives.
Stable Self-Concepts and Flexible Coping Strategies of People with Dementia Attending Dementia Self-Help Groups in Germany
Authors: von Kutzleben Milena , Panke-Kochinke Birgit
Published: August 2015

In this chapter, results from the qualitative longitudinal Selbstbestimmung und Intervention (SEIN) study conducted at the DZNE site in Witten are presented and discussed against the background of a previously conducted systematic review of the subjective needs, demands, and coping strategies of community-dwelling people with dementia. The objective of the study was to examine how participants of dementia self-help groups in the early and middle stages of the condition cope with their illness. A phenomenological approach with a life-course perspective served as the framework for the study. The findings suggest that a person's self-concept is not changed by dementia but instead adapts over the trajectory of the illness. Struggling between external control (defence against stigmatization) and external protection (being taken seriously), and aiming for “Inner Security” were central concerns for the participants. Biographical background and social network are determining factors in the development and use of coping strategies.
Self-Preservation in Individuals with Alzheimer's Disease
Authors: Fazio Sam , Mitchell David B
Published: August 2015

The purpose of this chapter is to highlight empirical evidence for the presence and persistence of self in individuals with Alzheimer's disease. First, the authors review their previous findings (Fazio & Mitchell, 2009) that revealed the persistence of self via language usage and delayed visual self-recognition data. Second, the authors present previously unpublished data demonstrating that both level of impairment (mild or moderate) and setting (residential or day center) are related to language usage. Third, the authors review the most recent literature about the self in individuals with Alzheimer's disease, as well as discuss social positioning and its impact on individualized care.
Changing Perception in Alzheimer's
Authors: Power G. Allen
Published: August 2015

In this chapter, the author will explain how the predominant models for viewing Alzheimer's and other forms of dementia fail to provide an adequate understanding of the changing perceptions of people who live with these conditions and consequently limit our ability to provide effective support. An alternative “experiential” model will be presented and used to reframe several concepts regarding the changing mind. New insights from this model inform an innovative approach to understanding and supporting people whose perceptual mechanisms and communication abilities differ from those of their care partners, and suggest a strength-based framework for enhancing several aspects of well-being, regardless of one's diagnosis or cognitive ability.
Quality and Safety
Authors: Rubin Daniel , Tung Avery
Published: August 2015

Quality improvement is a goal of all institutions but effective quality improvement programs have been difficult to create and sustain. Cardiac surgery has long been a pioneer in the quality improvement process through protocolization, large database analysis, and evidence based research. This chapter will discuss the theoretical foundation for quality improvement in medicine, and address current quality improvement strategies in the cardiothoracic ICU including care bundles, large database review, and externally promulgated quality programs such as the Surgical Care Improvement Project (SCIP) or the Physician Quality Reporting Initiative (PQRS). Controversies from national quality improvement programs including SCIP, extended staffing, and the value of quality culture will be discussed.
Antiarrhythmics, Inotropes, and Vasopressors
Authors: Tellor Bethany R. , Balsara Keki R.
Published: August 2015

Arrhythmias, low cardiac output syndromes, and low blood pressure are commonly faced complications in the cardiothoracic surgery patient. In order to provide appropriate clinical management, one must identify underlying etiologies while recognizing and understanding available treatment options. The objective of this chapter is to review common agents utilized to manage arrhythmias and maintain hemodynamic stability following cardiac surgery. Mechanisms of action, key clinical pearls and relevant literature pertaining to each agent will be discussed.
Anticoagulation Options
Authors: Mazzeffi Michael , Lowery Ashleigh
Published: August 2015

There are multiple indications for anticoagulation in the cardiac surgery intensive care unit including cardiac valve replacement, mechanical circulatory pumps (ECMO and ventricular assist devices), deep vein thrombosis prophylaxis, treatment of heparin-induced thrombocytopenia, and treatment of other thrombotic conditions including pulmonary embolism. Anticoagulant medications broadly fall into two categories: antiplatelet drugs and inhibitors of protein clotting factors. In this chapter we will review anticoagulant medications, therapeutic drug monitoring, common indications for anticoagulation, and the risks associated with anticoagulation after cardiac surgery.
Sedation and Analgesia
Authors: Brand Jordan
Published: August 2015

Patients in the cardiothoracic intensive care unit (CTICU) are subject to numerous physical and mental stresses. While most of these cannot be completely eliminated, intensivists have many tools in their armamentarium to alleviate patients' pain and suffering. This chapter will consider the importance of analgesia and sedation in the CTICU and the relevant consequences of over- or under-treatment. We will examine the tools available for monitoring and titrating analgesia and sedation in critically ill patients. The major classes of medications available will be reviewed, with particular attention to their clinical effects, metabolism and excretion, and hemodynamic characteristics. Lastly, experimental evidence will be assessed regarding the best strategies for treatment of pain and agitation in the CTICU, including use of non-pharmacologic adjuvants.
Vasodilating Agents
Authors: Kumar Shreyajit R. , Sosa Andrew , Margulis Ilan
Published: August 2015

This chapter discusses the salient features of arterial and venous dilating agents commonplace in the management of the post-cardiotomy surgical patient. A keen understanding of the underlying cellular mechanism, pharmacology, indication, safety profile, and controversies of clinical utility of vasodilating agents is imperative for routine use. The evidenced-based examination of each therapeutic modality will strengthen the practitioner's fund of knowledge for management of each pathophysiological state.
Acute Kidney Injury following Cardiac Surgery
Authors: Romito Bryan , Meltzer Joseph
Published: August 2015

The primary goal of this chapter is to provide the reader with an overview of basic renal physiology and function and to review the identification, pathogenesis, and treatment of acute kidney injury following cardiac surgery. Particular focus will be directed toward the diagnostic criteria for acute kidney injury, short- and long-term impacts on patient outcomes, role of novel biomarkers, mechanisms of acute renal injury, general management principles, preventative strategies, and the influence of anesthetic and surgical techniques on its development. The content of this chapter will serve to underscore a particularly harmful but likely underappreciated problem affecting patients in the cardiothoracic critical care setting.
Infection and Immune System
Authors: von Homeyer Peter
Published: August 2015

Infections are a major cause of mortality in intensive care unit (ICU) patients and the most common non-cardiac complications after cardiac surgery. Commonly encountered infections in the cardiothoracic ICU include pneumonia, bloodstream infections, and surgical site infections. At the beginning of this chapter, general measures of infection control and prevention are introduced. Those can help reduce infections and are best implemented in a bundled care fashion. Specifically for ICU patients, care bundles aimed at ventilator-associated pneumonia and central line-associated bloodstream infection have been successfully implemented, studied, and revised. In the next section, antibiotic treatment principles are described. Treatment with antibiotic drugs is an important part of therapy for infectious complications and is under continuous revision given the changing and diverse spectrum of microorganisms and the emergence of multidrug-resistance. In the central part of the chapter, specific infections are discussed in detail with regards to etiology, incidence, diagnosis, and therapy. Finally, the concept of systemic inflammatory response is described which is a common clinical problem after cardiac surgery, particularly with the use of cardiopulmonary bypass. Several immunologic mechanisms have been found to be associated with this and the clinical picture can be confused with sepsis.
Hematology and Transfusion
Authors: Antongiorgi Zarah , Gudzenko Vadim
Published: August 2015

The cardiac perioperative period presents a unique clinical scenario where the risk of life-threatening hemorrhage is balanced against the risk of thrombosis. Management practices are in a continual flux as practitioners respond to evidence showing the serious harms independently associated with anemia, bleeding and transfusion of blood (Ranucci, Aronson, et al., 2011a). Despite comprehensive transfusion guideline recommendations rates of blood transfusion range from 7.8% to 92.8% across US hospitals (Bennett-Guerrero et al., 2010). In this chapter we navigate the complex hemostasis and transfusion issues in cardiac surgery to provide clinicians a comprehensive understanding of the coagulation system in this specialized population. We emphasize a multidisciplinary team approach focused on risk stratification with preoperative optimization to minimize coagulopathy and bleeding followed by a tailored and conservative use of blood products for maximum patient benefit.
Endocrine and Metabolic Management in the Cardiothoracic ICU
Authors: Schulman Rifka C. , Mechanick Jeffrey I.
Published: August 2015

In this chapter, we review several important endocrine disorders frequently encountered in patients undergoing cardiothoracic surgery. Hyperglycemia, common in patients with and without diabetes mellitus (DM) in the perioperative period, has been linked to poor outcomes. Use of an intravenous insulin infusion early in the postoperative course, followed by transition to subcutaneous insulin, with maintenance of moderate glycemic targets (100-180 mg/dL) is currently the standard of care. Oral intake should be encouraged in the postoperative period, but if not possible, nutrition support with enteral nutrition should be considered. Critical illness related corticosteroid insufficiency (CIRCI) should be suspected in critically ill patients with refractory hypotension requiring vasopressors, especially in the setting of septic shock. Although diagnositic criteria are controversial, if suspected, empiric treatment with corticosteroids should be initiated. Nonthyroidal illness syndrome (NTIS) is common in critically ill patients and thyroid function tests should be interpreted with caution in this population.
Coronary Artery Disease
Authors: Arora Rakesh C. , Singal Rohit
Published: August 2015

Coronary artery bypass grafting (CABG), first introduced in 1968, is now one of the most common surgical procedures and the most common cardiac procedures worldwide. It is estimated that over 800,000 CABG surgeries are performed worldwide each year. The goals of CABG are to reduce mortality, prevent the progress of heart failure and reduce symptoms associated with coronary artery disease. This chapter deals with cardiac critical care issues that pertain to the patient undergoing CABG and potential post-operative complications.
Physiologic Monitoring
Authors: Osorio James , Tam Christopher
Published: August 2015

This chapter will provide a review of modern concepts of cardiovascular monitoring with emphasis on essential hemodynamic variables in the early post cardiac surgery patient. When defining circulatory function, importance of the entire circulatory system is underscored. This includes the function and interaction of the heart, blood vessels and circulatory blood volume to deliver sufficient amount of oxygenated blood to tissue beds. In post cardiac surgery patients, the pulmonary artery catheter remains the most widely used technology to assess cardiac function. This chapter highlights the importance of validation of less invasive and noninvasive hemodynamic monitors for the management of critically ill patients and early post cardiac surgery patients. In addition, this chapter describes the evolution of monitoring of post cardiac surgery and critically ill patients, examines different monitoring technologies and address controversial questions in modern practice as well as future directions.
Management of Bleeding in the Postoperative Cardiac Patient
Authors: Hensley Nadia , Sussman Marc
Published: August 2015

Bleeding in the postoperative cardiac surgical patient can be multifactorial. This chapter examines the preoperative and intraoperative risk factors for having significant postoperative bleeding. It also discuss the advantages and disadvantages of standard laboratory testing as well as point-of-care tests, such as thromboelastography (TEG) and thromboelastometry (ROTEM), in their diagnostic capabilities. Finally, we conclude with different treatment strategies in this challenging patient population along with diagnostic criteria of clinically significant postoperative bleeding and when to return to the operating room for re-exploration.
Cloud Computing Technologies for Open Connected Government
Authors: Mahmood Zaigham
Published: August 2015

Cloud Computing is an attractive paradigm for organisations that have a requirement to process large scalable distributed applications. It allows for self-provisioning of cloud resources to develop and host applications as well as acquire storage and networking resources. Connected Government (c-government) is an area where cloud technologies can be effectively used to achieve the benefits that the cloud paradigm promises. Social Media, Web 2.0 and mobile technologies can all help to further enhance the connected government capabilities. Using such technologies, governments and citizens can engage in real time in the electronic participation of a government's functioning. In this chapter, we introduce the cloud paradigm and then discussing the requirements of c-government, we outline how cloud technologies can help to achieve an open and transparent c-government. The aim is to provide the basics of relationship between c-government and cloud computing to set the scene for other contributions in this volume.
Adoption of Social Media as Communication Channels in Government Agencies
Authors: Alotaibi Reemiah , Ramachandran Muthu , Kor Ah-Lian , Hosseinian-Far Amin
Published: August 2015

Social media has become an integral part of many people's lives around the world. The main use of this communication channel is to connect with social circles. It is also widely used for commercial and business purposes. Governments are also keen to use social media as an alternative to the traditional communication channels. Nonetheless, when the level of use of social media in the government is compared to other fields, a clear gap becomes apparent. This chapter investigates the adoption of social media as a communication channel between citizens, public agencies and government departments; and considers a wide range of factors that affect the issue from the perspective of public agencies. This chapter presents an extensive literature review and proposes a framework that organises the critical factors that affect public agencies' efforts while implementing social media. We also provide a list of hypotheses to validate and evaluate the significance of these factors.
E-Government Initiatives through Cloud Computing
Authors: Anshari Muhammad , Almunawar Mohammad Nabil
Published: August 2015

The recent development of Web 2.0, cloud computing and its related technologies are contributing towards the tendency to utilize mobile services and e-participation through Web 2.0. It offers users the ability to have greater control of information flow in public spaces, making active participation highly possible. Citizens are empowered in the sense that they control the process of interaction(s), either with the government or with other citizens. This chapter presents a model for empowerment of citizens in e-government systems to enhance e-participation in e-government business processes through the cloud. We believe cloud computing is a platform to implement e-participation using Web 2.0 as many of the existing Web 2.0 applications are deployed in the cloud. The model is derived based on contemporary literature on empowerment and participation in e-government services. This model is expected to fill the gap in identifying a strategy of citizen empowerment in e-participation systems.
Cloud Computing Applications in the Public Sector
Authors: Manzoor Amir
Published: August 2015

Cloud computing brings key advantages to the governments facing conflicting IT challenges. However, the cloud paradigm is still fragmented and concerns over data privacy and regulatory issues presents significant barriers to its adoption. Cloud computing is expected to provide new ways to run IT in public sector. At the same time, it presents significant challenges for governments, and to make the most of cloud, public sector organizations need to make some important decisions. Governments planning to migrate to the cloud are actively moving to harness digital services but with different focus, reasons, and strategy. However, the degree of cloud adoption by the public sector around the globe varies significantly. Most governments are piloting cloud computing but there are huge differences between each country. This chapter explores the state of the art of cloud computing applications in the public sector; various implications and specific recommendation are also provided.
Security and Privacy Issues in Cloud-Based E-Government
Authors: Susanto Heru , Almunawar Mohammad Nabil
Published: August 2015

Cloud computing services have grown rapidly over the years. Government agencies are also interested in cloud-based provision for their E-government processes. Despite the advantages of cloud-related technologies, there are many security issues as well that fall into several categories of breaches with serious impacts. All these breaches have serious legal and reputational implications. Therefore, governments need to ensure that inherent security threats can be neutralized to ensure that data or information stored in the cloud are well protected. It is imperative for cloud-based e-government (CB-eGov) to use an information security management system (ISMS) to effectively manage CB-eGov. The purpose of this chapter is to discuss how cloud computing can be incorporated in an e-government implementation to improve its efficiency without compromising information security. As such, the government needs to take special care in ensuring security, privacy, and confidentiality of information stored in the cloud.
Cost Benefits of Cloud Computing for Connected Government
Authors: Chen Chin Kang , Almunawar Mohammad Nabil
Published: August 2015

Adoption of cloud computing is on the increase mainly to take advantage of the benefits offered and the potential utilization of the paradigm in implementing connected government (c-government) systems. Although, world governments have already recognized the usefulness of c-government in improving communication and coordination, service delivery, transparency and citizen's engagement, they need to also realise the recent development of cloud computing models in order to develop a proper strategy to incorporate cloud computing in implementing c-government. This chapter aims to discuss how c-government can benefit from the recent progress of cloud computing. Of course, cloud computing also brings some challenges. In this context, this chapter first presents the benefit and challenges of cloud computing for c-government implementation and then discusses the cost benefit of cloud computing for c-government and total cost ownership of cloud computing based systems. The chapter also highlights best practises and a migration strategy.
Exploring Vectorization and Prefetching Techniques on Scientific Kernels and Inferring the Cache Performance Metrics
Authors: Banu J. Saira , Babu M. Rajasekhara
Published: August 2015

Performance improvement in modern processor is staggering due to power wall and memory wall problem. In general, the power wall problem is addressed by various vectorization design techniques. The Memory wall problem is diminished through prefetching technique. In this paper vectorization is achieved through Single Instruction Multiple Data (SIMD) registers of the current processor. It provides architecture optimization by reducing the number of instructions in the pipeline and by minimizing the utilization of multi-level memory hierarchy. These registers provide an economical computing platform compared to Graphics Processing Unit (GPU) for compute intensive applications. This paper explores software prefetching via Streaming SIMD extension (SSE) instructions to mitigate the memory wall problem. This work quantifies the effect of vectorization and prefetching in Matrix Vector Multiplication (MVM) kernel with dense and sparse structure. Both Prefetching and Vectorization method reduces the data and instruction cache pressure and thereby improving the cache performance. To show the cache performance improvements in the kernel, the Intel VTune amplifier is used. Finally, experimental results demonstrate a promising performance of matrix kernel by Intel Haswell's processor. However, effective utilization of SIMD registers is a programming challenge to the developers.
A Novel Multi-Dimension Resource Recycling Mechanism for Cloud Data Centers
Authors: Chang Hong-Yi , Lin Tu-Liang , Huang Cheng-Kai
Published: August 2015

Cloud servers can be started with ineffective resource arrangement, and extra costs are produced if unnecessary servers are started. This is a substantial fee for the cloud service provider. Therefore, each cloud data center needs an efficient resource allocation mechanism to prevent unnecessary cloud servers from being started. In general, resource allocation problems can be classified into either one-dimension or multi-dimension aspects. In 2013, the authors have proposed a multi-dimension resource allocation algorithm that can improve the utilization of cloud servers by as much as 97%. However, most of previous studies are more concerned with solving the resource allocation problem. In fact, after a period of time, the applications will finish their jobs, and resources been occupied on the servers will be released, thus decreasing the utilization of cloud servers. Therefore, this paper proposes a novel multi-dimension resource recycling algorithm to optimize the server resource again, to recycle the excess cloud resources and to reduce the unnecessary operating cloud servers.
Research Trends in the Use of Mobile Learning in Mathematics
Authors: Crompton Helen , Burke Diane
Published: August 2015

The use of mobile learning in education is growing at an exponential rate. To best understand how mobile learning is being used, it is crucial to gain a collective understanding of the research that has taken place. This research was a systematic review of 36 studies in mobile learning in mathematics from the year 2000 onward. Eight new findings emerged: (1) The primary purpose of most studies was to focus on evaluating mobile learning. (2) Case studies and experimental design were the main research methods. (3) Most studies report positive learning outcomes; (4) Mobile phones were the mobile device used most often. (5) Elementary school settings were the most common research context. (6) The majority of researchers did not identify a specific mathematical concept being studied. (7) The majority of the studies took place in formal educational contexts; and (8) research on mobile learning in mathematics is geographically diverse.
A Design Based Research Framework for Implementing a Transnational Mobile and Blended Learning Solution
Authors: Palalas Agnieszka , Berezin Nicole , Gunawardena Charlotte , Kramer Gretchen
Published: August 2015

The article proposes a modified Design-Based Research (DBR) framework which accommodates the various socio-cultural factors that emerged in the longitudinal PA-HELP research study at Central University College (CUC) in Ghana, Africa. A transnational team of stakeholders from Ghana, Canada, and the USA collaborated on the development, implementation, and subsequent modification of the DBR framework. The recommended framework is a result of lessons learned during this project in Ghana and as such, it is shaped by the need to be responsive to the local cultural and contextual contingencies. The article offers practical recommendations on the implementation of a mobile learning project in a cross-cultural setting, and provides a discussion of the salient cultural factors and the corresponding culturally-sensitive adaptations needed in the design research process. The Cross-Culture Design-Based Research (CC-DBR) framework is proposed to inform future transcultural m-learning studies.
Towards Linked Open Business Registers
Authors: Varytimou Anastasia , Loutas Nikolaos , Peristeras Vassilios
Published: August 2015

Business data is high-value data and has a high reuse potential both in national and in cross-border settings. National business registers, tax authorities and others are currently holding such data. Opening up basic business data and making it available in machine-readable formats will definitely increase its reuse. In this work, the authors present, following a stepwise approach, how this can be achieved. They used a part of the dataset of legal entities, comprising approximately 29000 entities, maintained by the Greek Tax Authorities and described it with the Registered Organization vocabulary (RegOrg). The authors followed a publishing and consumption pipeline and made this data available as Linked Open Government Data (LOGD). They conclude this work with a number of findings and lessons learnt which can be useful for base registers and other owners of authoritative data that are considering moving towards LOGD.
Some Provisions of Rational Contact Conditions for a Composite Cutting Tool during Turning Operations on Intermittent Areas
Authors: Pavlov Evgeniy V. , Chervyakov Leonid M.
Published: August 2015

The possibility to improve the conditions of cutting rotary workpieces with intermittent areas by applying conventional tool materials is limited. However the use of tools with working members made from polycrystalline ultra-hard materials (composites) can be very efficient, provided that a negative influence of load impacts on the tool point and the major cutting edge at the moment of the tool lead-in is mitigated.The described method of turning (boring) intermittent surfaces offers more rational conditions for the contact between the tool cutting member and machined workpiece surface and permits eliminating negative effects of impact loads on the tool point. Proper conditions of cutting intermittent surfaces by tools made from 03 composite (petbor) or 10 composite (hexanite-r) can improve machining efficiency by up to 25% due to the intensification of cutting operations as well as to decrease tool purchase expenses by about 20%.
Analysis of the Influence of High Temperature Synthesis Parameters on the Structure Formation in the Mechanically Activated 3Ti+Al Powder Mixture
Authors: Loginova Marina V. , Filimonov Valeriy Yu. , Yakovlev Vladimir I. , Sytnikov Alexander A. , Negodyaev Alexey Z. , Shreifer Denis V.
Published: August 2015

The influence of basic high-temperature synthesis parameters on the process of structure formation in the mechanically activated powder mixture 3Ti+Al was investigated in the study. The synthesis was realized by the method of induction heating in the thermal explosion mode. The heating temperature of the mixture reached 1500°C during the solid state reaction. This temperature exceeded the adiabatic combustion temperature. The investigations of the phase structure formation processes were conducted by XRD methods. In order to obtain a Ti3Al single-phase compound, the optimal time-temperature parameters of the synthesis were determined.
Cladding of Ni-Cr-Si-B Powder Coatings by an Electron Beam Injected into the Atmosphere
Authors: Zimoglyadova Tatyana A. , Drobyaz Ekaterina , Bataev Vladimir , Kornienko Elena , Mul Daria , Ivanchik Ilija
Published: August 2015

The influence of the cladding rate on the structure and microhardness parameter of coatings obtained by non-vacuum electron beam treatment of Ni-Cr-Si-B powder mixtures was investigated. Modified layers characterized by the gradient structure and consist of dendritic grains and a eutectic located at the grain boundaries. It was found that the lowest microhardness level (300 HV) was characteristic of the coatings obtained when the workpiece was moving relative to an electron beam with a speed of 10 mm per second. This treatment regime allowed obtaining high-quality coatings 2.5 mm in thickness. However, a large thickness of fusion penetration led to the interfusion of the base metal with a coating material and a decrease in the concentration of alloying elements in the coating. Reducing the lifetime of the liquid phase during treatment prevented intensive diffusion processes. Increasing the treatment velocity to 20 mm per second doubled the cladded layer microhardness (up to 650 HV).
Depth Distribution of Temperature in Steel Parts during Surface Hardening by High Frequency Currents
Authors: Ivancivsky Vladimir , Parts Kristina , Popov Vyacheslav
Published: August 2015

Quenching of steel 45 using high-frequency induction-heating (440000 Hz) with simultaneous shower water cooling was studied. The possibility of liquid-phase creation in the bulk (appr. 0.2 mm) in the material being treated in the absence of melting on the surface was clearly demonstrated by both numerical simulation of the temperature field in the material during hardening and experimental results
Design of a Combined Setup for Simultaneous Measurements of the Microstructural and Thermo-Analytical Parameters of Nanogram-Size Samples
Authors: Rosenthal Martin , Melnikov Alexey P. , Rychkov Andrei A. , Doblas David , Anokhin Dmitriy V. , Burghammer Manfred , Ivanov Dmitriy A.
Published: August 2015

In the present paper, we describe an experimental setup combining micro- and nano-focus X-ray scattering and chip calorimetry (nanocalorimetry), which is designed for in-situ measurements on nanogram-size samples. Such combination of techniques capable to simultaneously probe the micro-structural and thermodynamic properties of materials can be useful for studies of materials having a complex phase behavior or prone to form metastable states. The setup is made compatible with micro- and nano-focus synchrotron beamlines.
Dry Sliding Wear Behavior and Wear Mechanisms of Thermally Sprayed WCCo-Coatings
Authors: Gontarenko Alexandra , Möhwald Kai , Deißer Todd Alexander , Maier Hans Jurgen
Published: August 2015

Thermal spraying is one of the most efficient methods to deposit hard wear resistant coatings. The coatings deposited by High-Velocity-Oxygen-Fuel spraying (HVOF) are characterized by high wear resistance and outstanding tribological characteristics. One of the most challenging tasks for tribologists is to develop surface treatments that allow for both operating the component without lubricants and at the same time minimize wear. WC-based cermets are a group of thermally sprayed coatings known to have high wear resistance under sliding friction conditions. An experimental study on the dry sliding wear behavior of WCCo HVOF-sprayed coating deposited onto a steel substrate is presented in the current paper. A pin-on-disc tribometer was used to carry out the wear tests.
Effects of Heating Atmosphere on Structure and Thermal Expansion of Aluminum Alloys
Authors: Afanasyef Vladimir , Popova Marina , Prudnikov Aleksandr
Published: August 2015

This paper analyses effects of boiling treatment of aluminum alloys (Al–(5-10)% Cu and Al–(5-10)% Si) in oxidizing atmosphere on their microstructure, hydrogen content and coefficient of linear thermal expansion (CLE). Boiling treatment was conducted in water solutions of KMnO4and KOH. Following an increase of boiling time from 15 to 75 hours hydrogen content in alloys first increases and then decreases which correlates with the dynamics of alloys’ microstructure and their coefficient of linear expansion. This study shows that atmosphere with high oxygen content induces acceleration of diffusion processes in aluminum alloys. If boiling time does not exceed 30 hours, hydrogen content in solid solution and etchability of grain boundaries of α-solid solution decrease and intermediate phases get partially dissolved. In our empirical study we demonstrated that boiling treatment of aluminum alloys in oxidizing atmosphere in the range of test temperatures 50-450°С leads to a reduction of the coefficient of linear expansion. The decrease of the coefficient of linear expansion is especially strong in the temperature range of 250-350°С. In particular, after boiling treatment of alloys Al–(5-10)% Cu in oxidizing athmosphere in the temperature range of 50–250°С their coefficient of linear expansion goes down by 10-12%. For alloys Al–(5-10)% Si boiling has a stronger effect on the coefficient of linear expansion – in the temperature range 250-350°С the CLE of these alloys decreases by 24-28%.
Energy Approach to Material Hardness Determination
Authors: Ogar Peter , Gorokhov Denis , Phedorov Ilya
Published: August 2015

Energy hardness is defined as energy density of material plastic displacement from the initial surface level. It is convenient to determine it from the kinetic indentation diagram constructed in the coordinates , where is a relative load, is a relative penetration of a spherical indenter. It dhould be note that a relative energy density is equal to multiplied by the parameter where varies within a narrow range for constructional materials used in machine building. A mean relative error in finding energy hardness by this approach does not exceed 5%. It is shown that for the majority of mechanical engineering materials energy hardness is intermediate between plastic hardness and Meyer’s hardness.
Influence of Thermal Cyclic Deformation and Hardening Heat Treatment on the Structure and Properties of Steel 10
Authors: Prudnikov Aleksandr , Popova Marina , Prudnikov Vladimir
Published: August 2015

The results of the influence of preliminary thermal cyclic deformation and subsequent hardening heat treatment on the microstructure and mechanical properties of hot-rolled sheet steel 10 are presented. It is shown that the use of preliminary thermal cyclic deformation of the steel 10 stock material results in a fine-grained structure of a hot-rolled sheet (3 mm thick) produced by an industrial technology. Deformation occurred at a temperature above AC3 (1250 °C), with cooling to 200-300 °C during 10 cycles and the deformation ratio per cycle being 6-8 %. Such a treatment before sheet hot-rolling allows increasing the strength characteristics (tensile strength, yield strength) by almost 30 %. It has been established that the use of subsequent heat treatment (quenching, 900 °C, water and tempering 1 h, 600 °C) leads to a further increase in strength characteristics by 15-20% while maintaining a sufficient level of ductility of sheet steel.
Mechanical and Tribological Properties of γ-TiAl-Based Coatings Produced by the Laser Cladding Technology
Authors: Maliutina Iuliia N. , Si-Mohand Hocine , Piolet Romain , Missemer Florent , Bertrand Philippe
Published: August 2015

Coatings from the γ-TiAl-based powder characterized by enhanced microhardness compared to that of titanium substrates were produced by the laser cladding technology. In the current paper wear mechanisms of substrates and coating materials under sliding friction conditions are described in detail. The wear of the substrate material was due to the seizure mechanism related to the mass transport of a considerable volume of the specimen material and a steel indenter. Only shallow notches without any mutual mass transport signs were observed on the coating surface after a sliding friction test.
Simulation of Structure Formation Processes of Dissimilar Steels Welded Joints Using an Intermediate Layer
Authors: Nikulina Aelita , Skeeba Vadim Yu. , Chevakinskaya Alexandra , Komarov Pavel
Published: August 2015

This paper shows the results of solving a 3D problem to define types of structures and tensions which can appear during the butt contact welding process of dissimilar steels through low carbon steel inserts. The finite element method to calculate welded structures was used. The thickness of inserts was the main variable parameter. According to the results of numerical simulation using inserts can increase the reliability of welded joints between pearlitic high-carbon steel and austenitic chromium-nickel steel. The best result was obtained by using an insert with a thickness less than 20 mm. Structural studies of the welded joints between high-carbon steel and chromium-nickel steel through low-carbon inserts confirm the results of mathematical modeling.
Efficiency of Steel Casting Production by Aluminothermic Metal Reduction
Authors: Sapchenko Igor G. , Zhilin Sergey G. , Komarov Oleg N. , Abashkin Evgeniy E. , Potianikhin Dmitrii A.
Published: August 2015

Conventional recycling methods of industrial waste such as ferrous and non-ferrous chips and broken graphite are ineffective. In this paper we investigate exothermic remelting of industrial waste. Parameters of the most effective recycling conditions which result in a maximal yield of reduced metal and high efficiency of steel casting have been determined. The influence of the aluminothermic mixture density, a fraction and a granulometric composition of the mixture initial components on the metallic yield is shown in the paper. The possibilities of reducing the material content in the thermite mixture are also discussed. The most productive process of steel casting with the use of industrial waste which makes it possible to reduce the overall dimensions of casting molds and the bulk of molding materials is proposed.
Surface Alloying of Cylindrical Steel Parts Using Non-Vacuum Electron Beam Treatment
Authors: Losinskaya Anna , Golovin Dmitry , Lenivtseva Olga , Lozhkina Elena
Published: August 2015

The technology of formation of high-carbon layers on the pipes of low-carbon steel using non-vacuum electron beam cladding is analyzed. Carbon fiber fabrics are used as a carbon source. High-carbon layers are formed on the surfaces of steel pipes due to the electron beam impact. The carbon concentration in high-carbon layers reaches 5.5 wt. % and decreases toward the base metal. The hardness of the obtained coatings reaches 8 GPa. Cladding of high-carbon layers allows increasing wear resistance of the material by 23 % compared to cemented and quenched steel.
The Effect of Heat Temperature on the Structure of Plasma Coating of the Ni-Cr-Si-B System
Authors: Kornienko Elena , Nikulina Aelita , Drobyaz Ekaterina , Plotnikova Natalya V. , Lapushkina Elizaveta , Kuz'min Victor
Published: August 2015

The powder of the Ni-Cr-Si-B system was applied on tubes of low carbon steel (0.2 % C) with the help of air-plasma spraying. The effect of heating temperature on the microstructure of obtained coatings was analyzed in this paper. The coatings were heated up to 500, 600, 700, 800, 900, 1000, and 1100 °C and cooled in the air. It was shown by the method of optical and scanning electron microscopy (SEM) and the X-ray diffraction analysis (XRD) that the same phases (γ-Ni, Ni3B, Ni3Si and Cr2B) were present in the coatings before and after heating. Chromium carbide Cr7C3 was observed in the coating structure after heating to above 1000 °C. Coatings which were heated to 1000 °C consisted of grains of the solid nickel base solution, micro volumes of the Ni+Ni3Si eutectic with inclusions of Ni3B and particles of Cr7C3. The coatings which were crystallized from a liquid state (heated up to 1100 °C) consisted of large areas of the solid nickel base solution and particles of chromium carbide Cr7C3. The space between nickel areas is filled by the Ni3Si+Ni3B eutectic.
Features of Forming the Surface Microrelief of Low-Wear Coatings by Electro-Diamond Grinding
Authors: Yanpolskiy Vasily V. , Rakhimyanov Konstantin Kh.
Published: August 2015

The results of electrochemical dissolution of coatings based on the PS12NVK powder composition in a water solution of neutral salts of NaNO3, Na2SO4 and NaCl are presented in the paper. It is shown that the dissolution of the mentioned material in the chosen compositions of electrolytes occurs in an active state in the range of the anode potential from φ=0 V to φ=4,5 V. The dissolution character of this coating is determined by electrochemical dissolution of coating materials, namely nickel (Ni) and cobalt (Co). It is revealed that an active dissolution of nickel (Ni) and cobalt (Co) leads to an irregular electrochemical dissolution of the coating surface, which decreases the machining quality. The results of studying the surface roughness relationship between the material with the coating based on the powder composition PS12NVK and electro-diamond grinding modes are presented. It is found that a minimum surface roughness magnitude Ra=0.9 μm is obtained when the table longitudinal feed is 90 mm/min.
Wear-Resistant Coating on Hard Alloy
Authors: Oskolkova Tatiana N.
Published: August 2015

In this research new data on the effect of zirconium as an ingredient of the ionic-plasma (Ti, Zr)N coating which is spread on the alloy VK10 KS was obtained. It was found that the introduction of zirconium into the coating composition led to an increase in nanohardness by 23 % up to 38500 MPa and in Young’s modulus – by 67 %, which indicated an increase of energy of atomic bonds and in strength of materials. Also, it led to an increase in an antifriction ability and decrease in the friction constant of the coating up to μ = 0,07, a satisfactory adhesive strength of coating, i.e. in general improved the service features of the whole alloy.
X-Ray Studies of Welded Joints of Ferrite-Pearlite Steels Working in Conditions of Low-Frequency Temperature and Force Loading
Authors: Golikov Nikolay I. , Platonov Anatoliy A. , Saraev Yuriy N.
Published: August 2015

The article is aimed to solve one of the important scientific and technical problems of improving operational reliability and safety of critical constructions exploited in Siberia and the Far North by developing new technological approaches to welding. In the article the results of X-ray diffraction studies of welded joints of steel 09G2S, obtained by different conditions of welding. Research results prove that pulsed arc welding is more preferred than direct current welding.
Equipment for In Situ Studies of the Surface Structure of Thin Surface Layers in the Process of their Formation
Authors: Bataev Vladimir Andreevich , Burov Vladimir G. , Grigorian Souren , Ivanov Dimitri A. , Plotnikova Natalya V. , Smirnov Alexander I.
Published: August 2015

The widespread use of polymeric semiconductor compositions for creating flexible and inexpensive solar cells can be achieved by providing the higher values of the coefficient of efficiency. The cost-effective production of polymer solar cells is expected at the efficiency of them not less than 10 %, while now its real level does not exceed 4 %. Many laboratories work to develop semiconductor compositions of organic materials as donors and acceptors which are fullerene derivatives or nanosize particles of semiconductor inorganic compounds [1-6]. The prospect of polymer used depends on the photovoltaic materials and the polymer purity and to a greater extent on the structure of the films formed from the compositions under development. In the search for ways to achieve higher performance of solar cells it is essential to optimize the technology of polymeric composition preparation, of which the active layer is formed, as well as optimization of the layer formation. In order to get information about the relationship between the structure of formed layer and its photovoltaic characteristics it is suggested to analyze the structure of the active layer simultaneously with the monitoring of its current-voltage characteristics. The study of the material structure directly in the process of its evolution seems an urgent task, since the majority of modern methods of structure investigation (light and electron microscopy, X-ray analysis) is not able to detect structural changes occurring in a short period of time. The most useful tool for monitoring the structure of polymer active layer is high intensity X-ray diffraction.
Metal Explosion Chambers and their Application
Authors: Shtertser Alexandr , Zlobin Boris , Stoyanovskii Oleg
Published: August 2015

The paper presents the principles of stress calculations for metal shells sustaining internal impulse loading. The designs of metal explosion chambers (EC) are described; examples of their utilization in scientific research and engineering applications are presented. Aside from conventional methods of the EC use, i.e. explosion welding, explosion hardening, powder compacting, synthesis of new materials, etc., recently the EC has found ever-widening applications in recycling discarded parts containing explosives, such as ammunition. The metal EC provides localization of every explosion damaging effect, improves the safety of works, and enables performing blasting operations both in industrial and laboratory conditions.
Prospective Designs of Flap Grinding Wheels – New Opportunities and Approaches to Import Substitution of Grinding Tools
Authors: Korotkov Alexander , Shatko Dmitry
Published: August 2015

At the present time the problem of import substitution of grinding tools is particularly of current interest. The current situation makes many foreign producers gradually leave the Russian market while domestic enterprises cannot offer competitive grinding tools that possess the characteristics and quality comparable to foreign analogs.
Specifications of Machine-Tool Equipment: Forecasting Techniques
Authors: Zverev Egor A. , Tregubchak Pavel , Vakhrushev Nikita , Ptitsyn Stanislav
Published: August 2015

The problems of theoretical grounds of machine tools specifications based on mathematic operational simulation are discussed in the paper. The proposed approach is based on the probability theory and mathematical statistics apparatus. It is universal and makes it possible to use automated design engineering systems at an initial development phase of the general concept of new equipment.