Pertinent Requirements Research Articles

Generalized time-delay reverse synchronization with error feedback coefficients

To enhance the application of discrete chaotic systems in secure communication, we introduce a novel generalized time-delay inverse synchronization method with error feedback coefficient. This paper outlines the derivation of an inverse master-slave time-delay generalized synchronization system using the Lyapunov theory with error feedback coefficient design, which is proposed for the first time. To verify the efficacy of the synchronization method, we constructed a new 4D discrete hyperchaotic system. The dynamic properties of the novel system, such as the phase diagram and Lyapunov exponents, are investigated. Empirical outcomes reveal that generalized discrete time-delay synchronization can be accomplished under certain conditions for the error feedback coefficient. The study utilizes the chaotic masking technique to encrypt and decrypt messages in the secure communication system. The experimental findings reveal that by integrating the synchronization approach with the time-delay context of secure communication, the applicable design of the synchronization procedure is adaptable and trustworthy, catering to the pertinent requirements of engineering, and has the capacity to attain instantaneous chaotic synchronization requisites.

Synthesis of CoNi by Electrodeposition Technique and its Application as an Electrocatalyst for Water Splitting

Water splitting is regarded as a highly efficacious methodology for obtaining hydrogen, intending to be employed for the purpose of renewable fuel production. However, the performance of this technique is constrained by the sluggish kinetics of the hydrogen evolution reaction in alkaline environments and the oxygen evolution reaction, which leads to significant energy inefficiency and excessive potential requirements. To enhance the reaction kinetics and efficiency of water splitting, there exists a pertinent requirement for an electrocatalyst that exhibits commendable efficiency. The primary objective of this study is to construct a cobalt-nickel (CoNi) electrocatalyst that facilitates water splitting. The present study employs the technique of electrodeposition for its experimental procedures. The findings of the study indicated that the CoNi sample, as observed through scanning electron microscopy with energy dispersive X-ray spectroscopy (EDX) analysis, exhibited a flattened, circular form and agglomeration. The EDX analysis yielded elemental composition results indicating a cobalt content of 20.51% and nickel content of 79.49% The X-ray diffractometer analysis reveals that the CoNi metal alloy has manifested a crystalline structure with a cubic configuration. The electrochemical impedance spectroscopy found that the charge transfer resistance of CoNi with the electrolyte solution was 1.48 kΩ. The data collected from the chronoamperometry test indicates the presence of a consistent and unchanging electrical current. Additionally, the cyclic voltammetry test presented Epa and Epc values of 0.4469 V and 0.3037 V, respectively, leading to a calculated ∆E of 0.1432 V. The research findings establish that the CoNi alloy, synthesized via the electrodeposition technique, exhibited a performance-effective electrocatalyst that closely approached the desired outcome.

The impact of the COVID-19 pandemic on the incidence of non-suicidal self-injury; a comparison between Iran and Belgium

Introduction The outbreak of COVID-19 has heightened mental health challenges among adolescents worldwide, while also hindering the development of effective emotion regulation strategies. Nevertheless, there exists a pertinent requirement to further investigate the psychological ramifications of COVID-19 on adolescents, as well as to discern disparities in these impacts across various nations. In order to address this gap in research, this study compares the prevalence of NSSI (characterized by purposefully injuring one's own body tissues without suicidal intention or engaging in behaviors that are not socially approved or sanctioned.), emotion regulation strategies, and psychopathology (internalization and externalization) among Belgian and Iranian adolescents pre- and during the COVID-19 pandemic. Method Adolescents between the ages of 13-21 from Iran and Belgium participated in a two-wave longitudinal design. In Iran, the sample consisted of 117 adolescents in wave 1 (April 2019) and 142 adolescents in wave 2 (Nov 2020). The Belgian sample consisted of 376 participants in wave 1 and 356 adolescents in wave 2. NSSI was assessed using the Self-Harm Inventory (SHI). Emotion Regulation was examined via the Emotion Regulation Inventory (ERI). The S trengths and Difficulties Questionnaire for Youth (SDQ) was used to assess psychological symptoms. Result Across the whole sample, lifetime NSSI prevalence was 35% in the first wave and 43.8% in the second wave. Longitudinal analysis across waves and counties did not show an increase in the prevalence of NSSI but did find that emotion dysregulation and internalizing symptoms are important risk factors for NSSI across countries. Emotional suppression and emotional dysregulation were the most prevalent emotion regulation strategies in Iran, whereas emotional integration was most prevalent in the Belgian sample. Conclusion Our study highlights cultural differences on the impact of COVID-19 on adolescent mental health. But it also indicates the importance of certain universal risk factors, for example, emotional dysregulation. These findings can inform developers to tailor programs for (early) intervention culturally.

Analytical Design of Synchrophasor Communication Networks with Resiliency Analysis Framework for Smart Grid

The advent of synchrophasor technology has completely revolutionized the modern smart grid, enabling futuristic wide-area monitoring protection and control. The Synchrophasor Communication Network (SCN) is a backbone that supports communication of synchrophasor data among Phasor Measurement Units (PMUs) and Phasor Data Concentrators (PDCs). The operator at the control center can visualize the health of the smart grid using synchrophasor data aggregated at PDCs from several PMUs. Since the core of the SCN is the existing IP network as an underlying communication infrastructure, the synchrophasor data is subjected to attacks that can compromise its security. The attacks, such as denial-of-service (DoS), can result in degradation of performance and even can disrupt the entire operation of the smart grid, if not controlled. Thus, a resilient SCN is a pertinent requirement in which the system continues to operate with accepted levels of performance even in response to the DoS. This article endeavors to propose a comprehensive resiliency framework for the SCN with enhanced resiliency metrics based on hardware reliability and data reliability. The proposed framework is deployed for a SCN pertaining to a practical power grid in India for its resiliency analysis. The proposed work can be regarded as a significant contribution to smart grid technology, as it provides a framework for resiliency analysis covering different aspects such as hardware reliability, data reliability, and parameters validation using the QualNet network simulator. Nevertheless, an analytical design of the hybrid SCN proposed in this work can even be extended to other topological designs of SCN.

Innovative Treatment Strategies to Accelerate Wound Healing: Trajectory and Recent Advancements.

Wound healing is highly specialized dynamic multiple phase process for the repair of damaged/injured tissues through an intricate mechanism. Any failure in the normal wound healing process results in abnormal scar formation, and chronic state which is more susceptible to infections. Chronic wounds affect patients’ quality of life along with increased morbidity and mortality and are huge financial burden to healthcare systems worldwide, and thus requires specialized biomedical intensive treatment for its management. The clinical assessment and management of chronic wounds remains challenging despite the development of various therapeutic regimens owing to its painstakingly long-term treatment requirement and complex wound healing mechanism. Various conventional approaches such as cell therapy, gene therapy, growth factor delivery, wound dressings, and skin grafts etc., are being utilized for promoting wound healing in different types of wounds. However, all these abovementioned therapies are not satisfactory for all wound types, therefore, there is an urgent demand for the development of competitive therapies. Therefore, there is a pertinent requirement to develop newer and innovative treatment modalities for multipart therapeutic regimens for chronic wounds. Recent developments in advanced wound care technology includes nanotherapeutics, stem cells therapy, bioengineered skin grafts, and 3D bioprinting-based strategies for improving therapeutic outcomes with a focus on skin regeneration with minimal side effects. The main objective of this review is to provide an updated overview of progress in therapeutic options in chronic wounds healing and management over the years using next generation innovative approaches. Herein, we have discussed the skin function and anatomy, wounds and wound healing processes, followed by conventional treatment modalities for wound healing and skin regeneration. Furthermore, various emerging and innovative strategies for promoting quality wound healing such as nanotherapeutics, stem cells therapy, 3D bioprinted skin, extracellular matrix-based approaches, platelet-rich plasma-based approaches, and cold plasma treatment therapy have been discussed with their benefits and shortcomings. Finally, challenges of these innovative strategies are reviewed with a note on future prospects.

Exploring Open and Distance Learning Reform at the National University of Lesotho: A Managerial Perspective

This study investigated how open and distance learning (ODL) reform was managed within the Institute of Extramural Studies (IEMS), at the National University of Lesotho (NUL). The reform was introduced during the 2017/18 academic year with first-year programmes in three departments: (a) Adult Education; (b) Business and Management Development; and (c) Research, Evaluation, and Media. The study employed interviews and analysis of institutional documents as data collection techniques. Interviews were held with eight programme coordinators, four department heads, and the director of IEMS. Purposive sampling was used to select the participants to the study given their strategic position in the management and implementation of the reform. Qualitative content analysis was used to interpret the data. The findings suggested that the ODL programmes were introduced without a policy and comprehensive plan. The implementation faced several challenges such as finance, as well as infrastructural and human resources. Evidence from the literature has suggested that compared to face-to-face strategy, ODL as an educational strategy requires special resources, support, and funding. Thus, curricular materials should be adapted for the ODL context, taking into account students’ characteristics. The study found that these pertinent requirements were not considered, and implementation continued as if the reform still constituted face-to-face or campus-based instruction.

Evidence for largest room temperature magnetic signal from Co2+ in antiphase-free & fully inverted CoFe2O4 in multiferroic-ferrimagnetic BiFeO3-CoFe2O4 nanopillar thin films

The ongoing quest for defect-free thin films systems that are apt for being used as spin filtering materials for spintronic applications did yet not deliver satisfying results regarding materials that would be up to the pertinent requirements. Using soft x-ray absorption spectroscopy (XAS) and x-ray magnetic circular dichroism (XMCD) measurements at the Co-L2,3 and Fe-L2,3 absorption edges, we have investigated the magnetic properties of a nanostructured thin film with self-assembled CoFe2O4 nanopillars embedded in BiFeO3, the latter being a well-known system for its combined multiferroic and spintronic properties. In this BiFeO3-CoFe2O4 heterostructure we observed a significant XMCD signal at the Co-L2,3 edges which turns out to be the largest among the presently reported for Co ions at room temperature. A quantitative analysis of the Co-L2,3 spectra unveils that such a large Co-L2,3 XMCD signal stems from the impeccable fully inverted spinel ordering of the A- and B-sites in antiphase-free CoFe2O4 nanopillars. This twofold perfect CoFe2O4 ordering feature yields an unprecedented optimization within a multifunctional ferrimagnetic-multiferroic thin film system highly relevant for spintronic applications, also resulting in an equally unprecedented macroscopic magnetic moment for such material as compared to its pure form as well as to technologically relevant thin film compound systems.

Channel Sounding and Measurements for Pico Cells for LTE and Future Wireless Networks

Wireless networks are the preferred future access networks for both defense and civilian deployments as part of telecommunication networks. The successful implementation of long term evolution (LTE) networks and applications such as the Internet of Things (IoT) in the telecommunication infrastructure has guaranteed rates of up to 100 Mbps while supporting ultra-dense wireless access network. With the incorporation of LTE-Advanced and fifth-generation wireless protocols, the data rates are expected to reach upto 1 Gbps. Hence, there is a pertinent requirement to carry out channel measurements at sub 1 GHz, 2 GHz, and 3 GHz bands to enable the design and implementation of optimum transceivers for pico-cells of LTE and future wireless networks. For the first time measurements and comparison with standard models of channel impulse response models have also been carried out in five different terrains namely Urban, Semi-Urban, Forest, Rural, and Desert terrains in the Indian sub-continent to effectively cover a variety of deployments of future wireless access networks for defense wireless networks

COVID-19 and International Freedom of Movement: a Stranded Human Right?

Governments confronted with a pandemic have a ‘knee-jerk’ reaction of imposing travel restrictions, despite the effectiveness of such measures not being supported by scientific evidence. In response to COVID-19, most countries imposed a ban on foreign travelers, with some States even closing borders to their own nationals and residents or prohibiting them from leaving. While border control is a legitimate prerogative that States can use to assess the health condition of travelers, travel restrictions are more complex and raise intricate legal questions. This article focuses on a specific category of travel restrictions: travel bans. These measures are a blanket prohibition applied to all or certain individuals, regardless of their health state, from crossing international borders. The validity of such measures depends on several elements. First, one needs to examine the applicable legal framework – the International Health Regulations and human rights treaties – and the standards they contain. Both sets of rules protect international mobility, but with different goals and scopes of application. Freedom of movement across borders is protected by the International Covenant on Civil and Political Rights, and comprises two interdependent rights: the right to leave and the right to return. Determining whether travel bans are lawful also depends on a second element: the status of the traveler, namely, whether they qualify as nationals, residents, or something else. After reviewing the relevant legal framework and (available) information on how travel bans were applied, this article questions whether the pertinent requirements and principles were respected. Some measures that were adopted in the name of public health seem hard (if not impossible) to justify. Entry bans covering nationals and residents are clearly a breach of the right to return. Exit bans are also problematic because they affect the exercise of the right to return. Both types of measures indirectly prevent family members from exercising their right to family reunification. Foreigners do not have a right to entry a foreign country but may be affected if they are prevented from leaving, thus becoming unable to exercise their return to return to their home country. This article examines a few of the more clear-cut cases were travel bans breached the rules and principles that should govern international mobility.

Nano-immobilized biocatalysts and their potential biotechnological applications in bioenergy production

Developing highly efficient biocatalyst is a pertinent requirement for biofuels production, in particularly biodiesel/bioethanol. To circumvent the minimal efficiency of conventionally used biocatalysts, nanotechnology paves a way by indulging nanoparticles as carriers of biocatalysts. The nanobiocatalysts so formed are applied as a tool for utilizing wide set of biomass related molecules into biofuels. The disadvantages of conventional biocatalysts such as catalyst deactivation, mass transfer, poisoning, and long reaction time can be outstripped by novel nanobiocatalysts. Nanobiocatalyst increases the catalytic activity; and this higher activity is because of the increased surface to volume ratio and hence it can act as a deoxygenation catalyst too. In recent years, exploiting modern tools for nanoparticles synthesis and characterization yielded high quality optimized and conditioned nanocatalyst systems such as metal oxide nanoparticles, magnetic nanoparticles, and carbon nanotubes to increase the biofuel productivity. Nanomaterial immobilized lipases and cellulases are predictably innovative catalysts having remarkable properties. The present article is critically discussed various nanomaterial immobilized enzyme development and its influence over production of biofuel. Continuous research and development and novel nanobiocatalyst engineering is essential for stabilization of biofuel producing companies.

Experimental Study on the System Performance of Adjacent Precast Concrete Box Beam Bridges

Analyses of catastrophic collapse of some adjacent precast concrete box beam bridges reveal the fact that the hinge joints between the adjacent beams were not sufficiently designed. The joint failure caused by deterioration is the result of system reliability deficiency of this type of bridges. To understand the system performance of the bridges, the redundancy and robustness of a bridge model with a scale of 1 ∶ 2, based on the prototype design drawings for 10‐meter adjacent box beam bridges in China, were assessed through a system safety evaluation procedure. The result confirmed the assumption that the redundancy and robustness of certain adjacent precast concrete beam bridges did not meet the pertinent requirements proposed in National Cooperative Highway Research Program (NCHRP) reports 406, 458, and 776 as a result of hinge joint failure. To address the current design deficiencies, a system factor is recommended in this paper to calculate the nominal resistance that reflects the level of redundancy of this type of bridges. In addition, a new framework is proposed to address the particular structural feature and topology of adjacent precast concrete beam bridges for the assessment of structural redundancy and robustness, which can reduce the computation complexity compared to existing approaches. The full‐range load test performed in this research verified the previous research results on bridge system safety that were mainly based on theoretical analysis and simulations.

Financial Technology Law: 'Understanding ICOs and the Legal Risks Surrounding Them and Developing a Legal Framework for Classification of Cryptoassets and Their Regulation'

The initiation of the fourth industrial revolution along with its correlated financial and technological innovations like cryptoassets in today’s financial markets, coupled with technological development and innovativeness, is bringing us closer to complete, total and true global interconnectedness. These cryptoasset markets although reasonably new, are evolving fast and furiously and have the potential to disrupt current financial markets and transform the future ones to come. As a product of these financial and technological innovations, Initial Coin Offerings have emerged in which cryptoassets are issued with the aim of raising capital from investors, divergent from traditional venture capital systems. However, new questions pertaining to the regulatory perimeters and classification of cryptoassets for regulatory purposes remain somewhat unanswered. In light of these circumstantial developments, this paper puts forth submissions proposing for the regulation of numerous cryptoassets which at present, remain unregulated, after analyzing and conducting a comparative study substantiating the differences between the US and UK regulatory architecture. Further, a new proposal for development of a framework for cryptoassets predominantly for regulatory purposes has been constructed. This is crucial because this sanctions the ability for the pertinent regulatory requirements and legislative rules to be clearly and readily identified, after having truly and correctly classified the cryptoasset involved. Lastly, propositions and recommendations in regards with work to be carried out in the near future are put forth along with submissions advocating statutory and regulatory amendments to the currently existing legal architecture in place.

Comparison of modelling techniques for assessment of spillways

Theoretical equations, computational fluid dynamics (CFD) and physical modelling are the three main commonly and commercially used techniques to analyse the performance of current or proposed dam spillways. The purpose of this paper is to compare the aforementioned modelling techniques, and ascertain the most appropriate application for pertinent features commonly required for analysis on a typical spillway. My employment allows me the unique opportunity to explore each technique with a critical analysis of individual performance and accuracy. It also allows me access to a great deal of physically modelled dam spillway data, against which to validate the CFD model to ensure accuracy. The paper will study each technique if applicable for the following pertinent requirements: Q/H curve, out-of-channel flow, velocity profiles, energy dissipation, pressure and hydraulic profile.

Abstract 3356: Working together to put kids first: Outreach strategies driving collaborative research, data sharing and cross-disease analysis to accelerate discoveries in pediatric cancer and structural birth defects

Abstract The Gabriella Miller Kids First Pediatric Research Program launched the Kids First Pediatric Data Resource Center (DRC) in 2017 as a collaborative, pediatric research effort with the goal of understanding the genetic causes of and links between childhood cancer and structural birth defects. The DRC is charged with developing data-driven platforms that integrate large amounts of genomic and clinical data, empowering the collaborative discovery, engagement, and necessary partnerships that are crucial for progress in our biological understanding of diseases, enabling rapid translation to personalized treatments for patients and accelerating discovery of genetic causes and shared biologic pathways within and across these conditions. The DRC is comprised of 3 cores including the Data Resource Portal Core, Data Coordination Core and the Administrative & Outreach Core (AOC). The AOC brings together researchers, physicians, and patient and foundation advocates to support collaborative research and data sharing to accelerate discoveries. The AOC specific aims are to employ outreach strategies including print, web, social media, in-person presentations, conferences, videos, webinars, e-newsletters, surveys, communication strategies, and reports to support accelerated discoveries. The AOC is committed to learning from the childhood cancer and birth defect communities. By capturing, synthesizing, and prioritizing unmet needs for development of the Kids First DRC portal, website, and materials, the AOC engages with researchers, clinicians, foundations, and patient advocates in the childhood cancer and structural birth defect communities. In its first year, the AOC partnered with 32 foundations to launch the Kids First DRC Portal and support data sharing throughout the research community. Key findings during the first six months of requirements gathering revealed the following unmet needs: a) Increase understanding of the disease types, research projects, and the investigators that are a part of the Kids First community b) Highlight the need for cross-disease analyses including structural birth defects and childhood cancers and c) Promote education on the data sharing, agreements, data availability and accessibility. The AOC, gathered pertinent user requirements, conducted educational activities, and engaged prospective users of the researcher community resulting in over 200 users and 22,000 portal views since launch and will continue to use feedback from the research community to further inform the development of the Kids First DRC tools and materials to meet the goals of the program. Citation Format: Tatiana S. Patton, Robert Moulder, Erin Alexander, Donna Vito, Jonathan Waller, Colleen Gaynor, Sarah Thomas, Bailey Farrow, Joseph Yamada, Kim Cullion, Danyelle Winchester, Angela Waanders, Allison Heath, Pichai Raman, Adam Resnick, Jena Lilly. Working together to put kids first: Outreach strategies driving collaborative research, data sharing and cross-disease analysis to accelerate discoveries in pediatric cancer and structural birth defects [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3356.

Operational and tegnological requirements for the profitable provision of rail freight transport

This article provides an overview of the most pertinent operational and design requirements of rail freight transport technology that could be instrumental in the profitable participation of rail transport in an economically deregulated freight transport market. The following three aspects are addressed: (1) The market segments that are serviced profitably by rail transport in industrial countries; (2) comparative cost of rail transport and the specific operational methods employed to make rail transport more cost advantageous; and (3) the most pertinent technological requirements set upon rail transport systems to operate commercially viably. Regarding technological requirements, the following aspects are elaborated upon: (1) train types and purpose-built wagons to appropriately serve specific market segments; (2) the type of freight terminals employed to effectively support rail transport operations; and (3) the types of handling equipment needed to enable rail transport to operate smoothly. The purpose-built wagon models and the types of train compositions to optimally adhere to rail transport operators’ specific needs, as well as the the most important factors that underlie wagon design, are discussed. Subsequently the functional requirements of the main terminal facilties that receive freight trains are discussed. Lastly, the handling equipment needed to load, unload and transload transportable freight on, from and between wagons and other modes of transport swiftly, safely and at lowest cost per freight unit are discussed.

A Comparative Analysis of e-government security frameworks Social-Technical Security Aspect

In recent years, most governments invested in the development of electronic government to improve governments efficiency and provide better services to businesses and citizens. As the successful implementation of the e-government depends on the viable security, all the concerns related to it need to be addressed. Security has become one of the crucial factors and primary challenges for achieving an advanced stage of e-government. In this regard, the paper investigates and analyzes six e-government security frameworks to assessing the security weaknesses of these frameworks from socio-technical security aspects. Meta-synthesis methodology used in this study, the meta-synthesis follows the steps used in meta-ethnography which adopted from Noblit and Hare. The finding is clearly showed that the socio-technical security missed to the rest of the security control principles and best practices elements. Therefore there is a clear need of a holistic socio-technical approach to be developed to match the pertinent security requirements into the e-government implementation.

Dynamic voids surrounded by shocked conventional polytropic gas envelopes

With proper physical mechanisms of energy and momentum input from around the centre of a self-gravitating polytropic gas sphere, a central spherical "void" or "cavity" or "bubble" of very much less mass contents may emerge and then dynamically expand into a variety of surrounding more massive gas envelopes with or without shocks. We explore self-similar evolution of a self-gravitating polytropic hydrodynamic flow of spherical symmetry with such an expanding "void" embedded around the center. The void boundary supporting a massive envelope represents a pressure-balanced contact discontinuity where drastic changes in mass density and temperature occur. We obtain numerical void solutions that can cross the sonic critical surface either smoothly or by shocks. Using the conventional polytropic equation of state, we construct global void solutions with shocks travelling into various envelopes including static polytropic sphere, outflow, inflow, breeze and contraction types. In the context of supernovae, we discuss the possible scenario of separating a central collapsing compact object from an outgoing gas envelope with a powerful void in dynamic expansion. Initially, a central bubble is carved out by an extremely powerful neutrinosphere. After the escape of neutrinos during the decoupling, the strong electromagnetic radiation field and/or electron-positron pair plasma continue to drive the cavity expansion. In a self-similar dynamic evolution, the pressure across the contact discontinuity decreases with time to a negligible level for a sufficiently long lapse and eventually, the gas envelope continues to expand by inertia. We describe model cases of polytropic index $\gamma=4/3-\epsilon$ with $\epsilon>0$ and discuss pertinent requirements to justify our proposed scenario.

Targeting and Dissolution Characteristics of Bone Forming and Antibacterial Drugs by Harnessing the Structure of Microspherical Shells from Coral Beach Sand

Pharmaceutical drugs for the treatment of metabolic bone diseases lead to a number of side effects due to the their uncontrollable dispersion throughout the body. [1] Therefore, many groups directed their research to develop devices that are targeted to specific organs or tissues and release the encapsulated drug in a highly regulated way. [2―7] The development of completely resorbable bone-filling biomaterials delivering drugs would offer a therapeutic approach of drug release and bone augmentation in a simple one-step process. [8―11] The biomaterials selected needs custom designs, to control the quantity and the duration of drug release and at the same time inducing desirable host cell responses and preventing bacterial infection. [12―15] Current synthetic biomaterials produced as drug delivery microspheres due to production difficulties contain not very well designed interconnected pores and fail to fill these pertinent requirements. Turning directly to nature such as marine structures for inventive solutions can help to solve these problems due to their structure, chemistry and architecture and their unique designs. [16―20] We demonstrate -for the first time- the potential of unique coral shells with specific microspherical structure and highly organised interconnected intra-pore designs to offer a number of desired functions for targeted delivery of Bisphosphonate (BP) (paminodrate) and an antibiotic (Gentamicin) for bone regeneration, repair and preventive antibacterial slow drug delivery.

Industrial implementation of novel procedures for the prediction of railway wheel surface deterioration

Adequate performance of the wheel-rail interface is essential for satisfactory operation of a railway system in terms of quality of service and maintenance effort. Pertinent requirements on efficiency tend to push the operation conditions towards higher loads and increased speed while the wheel-rail contact remains a small and highly stressed area. Dominating modes of deterioration due to high normal and tangential stresses are wear and rolling contact fatigue. Both kinds lead to surface material loss, in the former case as a slow rate profile geometry change with consequences to the dynamic performance and in the latter case different crack patterns and eventually spalling or shelling requiring reprofiling. In this paper the implementation of emerging technologies for the prediction of wheel surface deterioration in an engineering environment is summarised. Methods for the prediction of wear and profile geometry evolution as well as for the assessment of the risk for the onset of rolling contact fatigue are described. Example results from recent applications are given. In general it may be concluded that the implemented methods are becoming useful for the prediction of profile alterations, for instance hollow wear linked to conicity increase, and flange wear. The fatigue assessment methods are less mature and need further calibration but are still capable of indicating location and significance of risk for damage.

Nonlinear electron oscillations in a viscous and resistive plasma

Nonlinear, spatially periodic, long-wavelength electrostatic modes of an electron fluid oscillating against a motionless ion fluid (Langmuir waves) are given, with viscous and resistive effects included. The cold plasma approximation is adopted, which requires the wavelength to be sufficiently large. The pertinent requirement valid for large amplitude waves is determined. The general nonlinear solution of the continuity and momentum transfer equations for the electron fluid along with Poisson's equation is obtained in simple parametric form. It is shown that in all typical hydrogen plasmas, the influence of plasma resistivity on the modes in question is negligible. Within the limitations of the solution found, the nonlinear time evolution of any (periodic) initial electron number density profile ne(x,t=0) can be determined (examples). For the modes in question, an idealized model of a strictly cold and collisionless plasma is shown to be applicable to any real plasma, provided that the wavelength λ>>λmin(n(0),Te) , where n(0)=const and Te are the equilibrium values of the electron number density and electron temperature. Within this idealized model, the minimum of the initial electron density n(e)(xmin,t=0) must be larger than half its equilibrium value, n(0)/2 . Otherwise, the corresponding maximum n(e)(xmax,t=τ(p)/2) , obtained after half a period of the plasma oscillation blows up. Relaxation of this restriction on n(e)(x,t=0) as one decreases λ , due to the increase of the electron viscosity effects, is examined in detail. Strong plasma viscosity is shown to change considerably the density profile during the time evolution, e.g., by splitting the largest maximum in two.