bluuebunny/crossref_metadata_2025 huggingface dataset:
Protein Structure Prediction using Homology Modeling
Authors: Gupta Akanksha , Mohanty Pallavi , Bhatnagar Sonika
Published: May 2016

Sequence-structure deficit marks one of the critical problems in today's scenario where high-throughput sequencing has resulted in large datasets of protein sequences but their corresponding 3D structures still needs to be determined. Homology modeling, also termed as Comparative modeling refers to modeling of 3D structure of a protein by exploiting structural information from other known protein structures with good sequence similarity. Homology models contain sufficient information about the spatial arrangement of important residues in the protein and are often used in drug design for screening of large libraries by molecular docking techniques. This chapter provides a brief description about protein tertiary structure prediction and Homology modeling. The authors provide a description of the steps involved in homology modeling protocols and provide information on the various resources available for the same.
A Framework for Improving Logistics Operations at Container Terminals
Authors: Mar-Ortiz Julio , Gracia Maria D. , González-Ramírez Rosa G.
Published: May 2016

Container terminals as strategic nodes in global supply chains require improving logistics operations in order to compete. This chapter addresses the problem of how to improve logistics operations to increase the container terminal's throughput and capacity by lean logistics principles and simulation optimization methods. Current research in container terminals is focused on solving specific decision problems at container terminals, e.g., determining the optimal number of equipment to increase productivity. However, there is little evidence of studies related to designing operations to increase performance indicators, such as truck turnaround times or crane productivity, through simulation-optimization models and lean logistics principles. Consequently, the aim of this chapter is to describe a methodological framework for improving logistics operations at container terminals using lean logistics principles and simulation-optimization techniques. A research agenda to explore the applicability and usefulness of the proposed approach on a set of integrated problems is finally proposed.
Improving the Supply Chain (SC) Stream with Green Product Design (GPD) Strategy
Authors: Villanueva Rodrigo , Jimenez-Macias Emilio , Blanco-Fernandez Julio
Published: May 2016

The current Supply Chain (SC) is under change. The traditional way to generate a product contained the following stages: product design, raw material selection, material transportation, manufacturability, distribution and disposition at end of life. Product design for instance, is considered an extremely important stage of a product, being that, it directs the way the product can potentially be managed along the SC. It defines the raw material to be used, the possible supplier to select, the industrial processes involved in its fabrication, the packaging for its transportation and the newest stage where the product reaches its end of life and needs to be disposed. The Product design then becomes Green Product Design (GPD), where energy, time, resources become critical for a company. GPD takes into account the whole product life cycle. This chapter presents the importance of having a GPD process into the SC, the way to incorporate it, and the benefits of implementing it into the SC.
Ergonomic Assessment of Material Handling in CV Joint Assembly
Authors: Hernández-Arellano Juan Luis , Serratos-Perez J. Nieves , Peinado Coronado Porfirio
Published: May 2016

Work-Related Musculoskeletal Disorders (WRMSD) is one of the most common problems that affect productivity in industrial processes. This chapter presents the ergonomic evaluation of the main tasks in a Constant Velocity (CV) Joint assembly process. Tasks selected and evaluated using ergonomic methods were the transport of manufacturing parts on carts, parts supply at the workstation, materials handling within the workstation, and loading of the finished product on pallets. The ergonomic evaluation was performed by applying both Rapid Entire Body Assessment (REBA) method, and Rodgers' Biomechanical analysis. The analysis showed the existence of very high and high risk levels. Body regions most affected were elbow, shoulder, trunk, hip, legs, arm, and wrist. Ultimately, this research highlights the urgent need to perform corrective actions and further assessment for the CV Joint assembly process tasks studied.
Operational Risk Management in Third Party Logistics (3PL)
Authors: Manotas-Duque Diego Fernando , Osorio-Gómez Juan Carlos , Rivera Leonardo
Published: May 2016

Supply chain risk management processes are among the most important activities in the value chain of any industry. The supply chain risk management process includes different activities, focused on the identification, measurement, assessment, and mitigation of the main risk sources that can affect a supply chain. The increasing complexity facing global supply chains generates the need for suppliers to collaborate in different processes in a supply chain. In this context, Third Party Logistics Providers (3PL) have been widely promoted by the phenomenon of outsourcing, on which companies increasingly rely. The growth in logistics outsourcing is mainly attributed to the benefits it brings in terms of reducing costs, improving performance, allowing companies to focus on their core businesses and building virtual enterprises through strategic alliances. In this chapter we develop a model to identify the operational risk factors of a 3PL provider.
Automatic Defect Detection and Classification of Terminals in a Bussed Electrical Center Using Computer Vision
Authors: Villegas Osslan Osiris Vergara , Sánchez Vianey Guadalupe Cruz , Domínguez Humberto de Jesús Ochoa , García-Alcaraz Jorge Luis , Jorge Ricardo Rodriguez
Published: May 2016

In this chapter, an intelligent Computer Vision (CV) system, for the automatic defect detection and classification of the terminals in a Bussed Electrical Center (BEC) is presented. The system is able to detect and classify three types of defects in a set of the seven lower pairs of terminals of a BEC namely: a) twisted; b) damaged and c) missed. First, an environment to acquire a total of 56 training and test images was created. After that, the image preprocessing is performed by defining a Region Of Interest (ROI) followed by a binarization and a morphological operation to remove small objects. Then, the segmentation stage is computed resulting in a set of 12-14 labeled zones. A vector of 56 features is extracted for each image containing information of area, centroid and diameter of all terminals segmented. Finally, the classification is performed using a K-Nearest Neighbor (KNN) algorithm. Experimental results on 28 BEC images have shown an accuracy of 92.8% of the proposed system, allowing changes in brightness, contrast and salt and pepper noise.
The Role of Strategic Outsourcing in Global Business
Authors: Kasemsap Kijpokin
Published: May 2016

This chapter reveals the role of strategic outsourcing in global business, thus describing the theoretical and practical concept of strategic outsourcing; the management theories related to strategic outsourcing; the applications of Business Process Outsourcing (BPO) and Information Technology Outsourcing (ITO); and the significance of strategic outsourcing in global business. The fulfillment of strategic outsourcing is vital for modern organizations that seek to serve suppliers and customers, improve business performance, enhance competitiveness, and reach continuous achievement in global business. Therefore, it is necessary for modern organizations to explore their strategic outsourcing, establish a strategic plan to usually check their practical advancements, and immediately respond to strategic outsourcing needs of customers in modern organizations. The chapter argues that applying strategic outsourcing in global business has the potential to increase organizational performance and attain business goals in the digital age.
The Management Commitment and Its Impact on Economic and Competitive Benefits Gained by the Implementation of Kaizen in the Industry
Authors: Oropesa Midiala , Del Risco Ricardo , Pérez Roberto , Lara Jesús M.
Published: May 2016

This chapter provides an analysis of the effect of management commitment as a critical success factor Kaizen, on the economic and competitive benefits obtained by implementing the same in industrial enterprises during their planning stage is presented. To collect information apply 423 questionnaires distributed to 68 companies in the states of Tabasco, Sinaloa and Chihuahua in Mexico. The partial least squares method was used with the software WarpPLS 4.0 software to develop a model of structural equations that explain such effects. The results show that when there is a high management commitment, this impacts on the economic and competitive benefits to companies directly and positiva.Como result of this study is shown in a tangible way, the impact of a certain critical success factor Kaizen, the benefits of implementing it, essential to their sustainability over time element.
Sustainable Operation Planning and Optimization in Manufacturing
Authors: Vikas  , Roy Supriyo , Kumar Kaushik
Published: May 2016

Demands on today's products have become very complex as buyers expect enhanced quality. Choosing a proper integrated manufacturing technology is the most difficult and time consuming act for enterprises. Again, Planning plays a crucial role in embedding sustainability into the day to day operations and businesses maintain a strong focus on factors that have a clear and direct effect on their economic performance like cost of materials, profit etc. Electro-Discharge Machining (EDM) is a thermoelectric energy based non-traditional machining processes with Material Removal Rate (MRR), Overcut and Surface Roughness as important outputs. People working on EDM have used a number of ways to optimize them. The objectives being more efficient material removal coupled with reduction in overcut and improved surface quality. In this study the same are individually and simultaneously optimized using Taguchi method on EN41 material and the best combination of the input parameters were identified. Results are validated to show its efficacy in using these in different manufacturing shop floors
Management Practices for Processes Optimization
Authors: Nedelko Zlatko , Potocan Vojko
Published: May 2016

The main purpose of this paper is to examine utilization of management practices in Slovenian industrial organizations. The focus is on examination of the level of utilization of management practices in industrial organizations and comparison to the level and pattern of use with Slovenian organizations in services. The paper discusses the role and importance of typical industrial practices for processes optimization and processes outcomes. Research results reveal that employees in industrial organizations significantly more use management practice to support their processes then those employees working in services organizations. Also the pattern of management practices utilization in industrial and service organizations is rather different. The sample for this study includes 357 responses from employees in Slovenian organizations. In discussion we addressed the link between management practices and processes optimizations, while in practical implications are outlined suggestions how to use management practices in order to improve performance of industrial processes.
Evaluating Learning Experience through Educational Social Network Support in Blended Learning
Authors: Mirabolghasemi Marva , Iahad Noorminshah A.
Published: May 2016

The Community of Inquiry (CoI) model has been used for exploring various aspects of blended learning courses using technology such as Course Management Systems (CMSs). However, there is a lack of research literature evaluating CoI in environments where students use an educational social network in addition to a CMS and face to face teaching and learning. This study investigates a learning experience in blended learning that combines the usage of a CMS, Edmodo, which is an educational Social Network Site (SNS) and face to face teaching and learning. The results have shown a significant relationship and prediction of overall learning experience in relation to teaching, cognitive and social presence in blended learning. Moreover, social presence is the most significant factor to predict the overall learning experience of students.
Learning about Blended Learning through Students' Experiences
Authors: Carter Margaret Anne , Pagliano Paul , Knight Cecily , Goldie Donna
Published: May 2016

The digital age together with the political and economic agenda to make higher education more accessible and cost effective are challenging teaching academics worldwide to rethink and redesign their pedagogical practices. The challenges include how to respond to increasingly diverse twenty first century learners who demand flexibility, and the requirements of a more service driven economy. For a program to be successful in higher education's current learnscape, teaching and learning need to optimise students' experiences and learning outcomes. The exploratory study discussed in this chapter investigates seventy-three postgraduate students' experiences with blended learning in guidance and counselling programs in one Australian university with an offshore branch campus in Singapore. The study aims to inform the future design and delivery of teaching and learning within blended learning spaces with a focus on pedagogical practices for student engagement. As such, it contributes to the body of knowledge about learning design that enhances student learning experiences.
Improving Teaching Practice in Early Childhood Supported by Mobile Technology
Authors: MacCallum Kathryn , Bell Heather R.
Published: May 2016

This chapter discusses the findings of an ethnographic case study investigating the implementation of mobile learning at an early childhood centre in Hawkes Bay, New Zealand. The study describes how mobile technology is being used to support children's learning and communication. The findings show that the devices are an integral part of the learning culture of the centre. The devices are being used to actively engage children in the learning environment and support teaching inquiry. As one of the early studies to investigate how mobile technology is being used in early childhood education, the current study provides pedagogically sound examples and insight on how mobile technology can be embedded into early childhood. The study is seen as a starting place for more in-depth investigations into the impact of mobile learning on young children's learning.
Increasing Learner Interaction in Large-Scale Lectures by Using a Mobile Learning Application
Authors: Lehmann Katja , Söllner Matthias , Leimeister Jan Marco
Published: May 2016

Universities face increasing numbers of students leading to increasingly large lectures, and decreasing interaction and feedback, which are important factors for individual learning success and satisfaction. The use of IT can help in overcoming this challenge by increasing the interaction in large-scale lectures without massively increasing the workload of lecturers. This paper presents the design, use and evaluation of a mobile-learning application aiming to increase the interaction in large-scale lectures and the success of learners. For designing the application, the authors follow a design science research approach. The authors rely on insights from interaction theory as well as requirements gathered from lecturers and students in a focus group workshop. With the implementation, large-scale lecture related limitations can be overcome and the results help lecturers to face the according challenges. The results emphasize the potential of IT for university teaching and provide transferable insights for practical use in other learning scenarios.
Create, Transform, and Share
Authors: Ranieri Maria , Bruni Isabella
Published: May 2016

This chapter explores the potential of mobile learning for creativity in formal and informal contexts of learning with a focus on media production and self-expression. In doing so it attempts to move beyond binary views around the nature of creativity and the role of technologies for creative learning. It presents the literature on how creativity and its relationship with technologies have been conceptualized, especially in education, and provides the theoretical underpinnings that supported the study. In particular, it refers to the Vygotskyan perspective of creativity as a transformative (social) process of culture and the self, and looks at digital technologies' affordances to reflect on their potential for learning. It describes three projects addressing young people and entailing the creation of digital artefacts through mobile devices. It highlights learners' and teachers' perspectives and shows how mobile devices can serve as cultural resources that young people may use for meaning making and transforming themselves.
Mobile Application Development by Students to Support Student Learning
Authors: Dekhane Sonal , Tsoi Mai Yin , Johnson Cynthia
Published: May 2016

The ubiquity of mobile devices, their portability and their unique gesture recognition features make them an apt educational tool, especially in the STEM fields. The traditional pen and paper practice method can be transferred to a digital format and the content can be made available to students anywhere and at any time. In this chapter the authors discuss how mobile application development projects can be used to benefit students in multiple STEM disciplines at the same time by creating a symbiotic, business-like relationship between students enrolled in a software development course and students in other STEM courses (end-users). The authors will discuss the learning needs of students and the details of thoughtful mobile application design incorporating various learning theories. This chapter will also discuss various examples of educational mobile apps created, their usability testing results and their effect on student learning.
Mobile Learning in Science and Mathematics Teaching
Authors: Almeida Rosiney Rocha , Araújo Jr. Carlos Fernando
Published: May 2016

This chapter, the authors analyze mobile learning literature addressing formal teaching situations in the field of science/mathematics education. The chapter describes a systematic review of relevant literature, investigating work published between 2005 and 2014. Based on the findings of this review, the results reveal that since 2009 interest in the academic community for research involving m-learning in science and mathematics teaching has intensified. An emphasis on the growing need for research involving m-learning at undergraduate levels is evident. The study notes positive reported results on the impact of m-learning in science and mathematics teaching, notably in assisting ease of learning, promoting student interest and collaborating with positive, motivating attitudes, encouraging meaningful commitment among students in learning activities.
Taking Advantage of MOOCs in K-12 Education
Authors: Briggs Samantha , Crompton Helen
Published: May 2016

Technological opportunities are opening new ways for educators to enhance K-12 instruction. While many educators are incorporating digital technologies into their teaching, there is evidence to show that K-12 educators have a lack of training, time, and resources to implement learner-centered digital instruction. Massive Open Online Courses (MOOCS) have gained a reputation for providing online learning in higher education and are now extending to K-12. The unique digital advantages as well as the rising number of students enrolled in schools has led to discussions about the potential of MOOCS for students in K-12 (ages 4-19 years) education. This chapter provides a review of the literature of early pioneering work of MOOCs in K-12 within North America. Early MOOC classes are explicated and positives and challenges discussed. It appears from the review that there is a place for MOOCs to be embedded into a blended K-12 environment to extend and enhance existing curricula.
Glossário hipermídia no ensino-aprendizagem implícito de vocabulário em língua inglesa
Authors: Procópio Renata Bittencourt , Ribeiro Patrícia Nora de Souza
Published: May 2016

Considerando a carência de estudos sobre a influência da proficiência linguística no aprendizado implícito de vocabulário em ambiente hipermídia, este estudo investiga a relevância do glossário hipermídia no ensino-aprendizagem implícito de vocabulário de alunos de nível elementar de inglês como língua estrangeira. No plano teórico, o estudo é fundamentado nos pressupostos das seguintes teorias: Abordagem Conexionista, que busca explicar a cognição humana e a aquisição de conhecimento, e Teoria Cognitiva do Aprendizado Multimídia, proposta por Mayer (2001), que busca explicar o processamento da informação em ambiente de aprendizagem multimodal. Este estudo apresenta a seleção e o desenvolvimento de um ambiente hipermídia de leitura contendo um glossário hipermídia orientado por parâmetros delimitados no plano teórico. Esse material, utilizado na geração de dados, foi aplicado a 39 alunos de nível elementar de inglês da Universidade Federal de Juiz de Fora, divididos em dois grupos (A e B). O ganho médio de aprendizagem obtido tanto no Grupo A, 28,5 [p.p.], quanto no Grupo B, 21 [p.p.], indicam que o glossário hipermídia pode contribuir para o aprendizado implícito de vocabulário de alunos de nível elementar, com destaque para a anotação visual.
Oh, oh, o gigante acordou! Brasil, junho de 2013: conceptualizações e metáforas das manifestações
Authors: Almeida Ariadne Domingues
Published: May 2016

Apresentam-se resultados de um estudo cujo principal objetivo foi examinar o processo de conceptualização das manifestações brasileiras de 2013 e dos seus agentes sociais. Como norte teórico-metodológico, seguiram-se os pressupostos da Linguística Cognitiva, baseando-se em autores como Lakoff e Johnson (1980), Kövecses (2009), Grady (1997), entre outros. O corpus examinado foi constituído por postagens feitas no Facebook, coletadas em junho de 2013. Após a análise qualitativa dos dados, concluiu-se que as manifestações, por exemplo, podem ser conceptualizadas, por meio do mecanismo da metáfora, como guerra.
A análise do discurso está na moda?
Authors: Paixao Humberto , Sousa Katia Menezes de
Published: May 2016

Este artigo busca articular análise do discurso francesa e moda. Com o intuito de responder à questão ‘A análise do discurso está na moda?’, o texto divide-se em duas partes: primeiro, levando em consideração que a moda pode ser entendida como um construto, propõe-se uma reflexão sobre a sua inserção no campo da AD e, segundo, sobre a própria existência e sucesso desta disciplina no interior dos estudos linguísticos, o que a faz estar hoje ‘na moda’.
Agraciamento da Grande Medalha da Inconfidência a João Stédile sob a perspectiva da Linguística Sistêmico-funcional
Authors: Modolo Marcelo , Oliveira Alfredo Vital
Published: May 2016

Este artigo visa a apresentar uma análise de seis textos que tratam da repercussão do recebimento da Grande Medalha da Inconfidência por João Pedro Stédile, coordenador do Movimento dos Sem-Terra, em cerimônia pública, que ocorreu em 21 de abril de 2015, em Belo Horizonte, Estado de Minas Gerais. Para tanto, utilizou-se o sistema sociossemântico desenvolvido a partir da Linguística Sistêmico-funcional de Halliday e Matthiessen (2004). Os textos do corpus foram analisados e classificados dentro de quatro grandes grupos (materiais, mentais, relacionais e verbais), de acordo com a classificação cognitivo-funcional de Lavid, Arús, e Zamorano-Mansilla (2010). Dos resultados dessa análise, pode-se verificar que os autores utilizaram, de forma semelhante, o processo material como o mais frequente; que os sites que, em tese, possuem um público mais escolarizado utilizaram com maior frequência processos mentais; que autores mais bem definidos ideologicamente adotam uma rígida postura, ou positivas ou negativas, e, raramente, utilizam da voz de terceiros, para indicar seus posicionamentos. Assim, ficou nítida a influência do contexto de cultura (onde se inclui a ideologia) de cada um dos autores dos textos nas escolhas linguísticas de cada um, observadas sob a perspectiva da metafunção ideacional, e analisadas por meio do sistema da transitividade dos processos oracionais.
NKG2D–NKG2D Ligand Interaction Inhibits the Outgrowth of Naturally Arising Low-Grade B Cell Lymphoma In Vivo
Authors: Raju Saravanan , Kretzmer Lena Z. , Koues Olivia I. , Payton Jacqueline E. , Oltz Eugene M. , Cashen Amanda , Polic Bojan , Schreiber Robert D. , Shaw Andrey S. , Markiewicz Mary A.
Published: May 2016

It is now clear that recognition of nascent tumors by the immune system is critical for survival of the host against cancer. During cancer immunoediting, the ability of the tumor to escape immune recognition is important for tumor development. The immune system recognizes tumors via the presence of classical Ags and also by conserved innate mechanisms. One of these mechanisms is the NKG2D receptor that recognizes ligands whose expression is induced by cell transformation. In this study, we show that in NKG2D receptor–deficient mice, increasing numbers of B cells begin to express NKG2D ligands as they age. Their absence in wild-type mice suggests that these cells are normally cleared by NKG2D-expressing cells. NKG2D-deficient mice and mice constitutively expressing NKG2D ligands had increased incidence of B cell tumors, confirming that the inability to clear NKG2D ligand–expressing cells was important in tumor suppression and that NKG2D ligand expression is a marker of nascent tumors. Supporting a role for NKG2D ligand expression in controlling the progression of early-stage B cell lymphomas in humans, we found higher expression of a microRNA that inhibits human NKG2D ligand expression in tumor cells from high-grade compared with low-grade follicular lymphoma patients.
Andrographolide Restores Steroid Sensitivity To Block Lipopolysaccharide/IFN-γ–Induced IL-27 and Airway Hyperresponsiveness in Mice
Authors: Liao Wupeng , Tan W. S. Daniel , Wong W. S. Fred
Published: May 2016

LPS and IFN-γ alone or in combination have been implicated in the development of steroid resistance. Combined LPS/IFN-γ strongly upregulates IL-27 production, which has been linked to steroid-resistant airway hyperresponsiveness (AHR). Andrographolide, a bioactive molecule isolated from the plant Andrographis paniculata, has demonstrated anti-inflammatory and antioxidant properties. The present study investigated whether andrographolide could restore steroid sensitivity to block LPS/IFN-γ–induced IL-27 production and AHR via its antioxidative property. The mouse macrophage cell line Raw 264.7, mouse primary lung monocytes/macrophages, and BALB/c mice were treated with LPS/IFN-γ, in the presence and absence of dexamethasone and/or andrographolide. Levels of IL-27 in vitro and in vivo were examined and mouse AHR was assessed. Dexamethasone alone failed to inhibit LPS/IFN-γ–induced IL-27 production and AHR in mice. Andrographolide significantly restored the suppressive effect of dexamethasone on LPS/IFN-γ–induced IL-27 mRNA and protein levels in the macrophage cell line and primary lung monocytes/macrophages, mouse bronchoalveolar lavage fluid and lung tissues, and AHR in mice. LPS/IFN-γ markedly reduced the nuclear level of histone deacetylase (HDAC)2, an essential epigenetic enzyme that mediates steroid anti-inflammatory action. LPS/IFN-γ also decreased total HDAC activity but increased the total histone acetyltransferase/HDAC activity ratio in mouse lungs. Andrographolide significantly restored nuclear HDAC2 protein levels and total HDAC activity, and it diminished the total histone acetyltransferase/HDAC activity ratio in mouse lungs exposed to LPS/IFN-γ, possibly via suppression of PI3K/Akt/HDAC2 phosphorylation, and upregulation of the antioxidant transcription factor NF erythroid-2–related factor 2 level and DNA binding activity. Our data suggest that andrographolide may have therapeutic value in resensitizing steroid action in respiratory disorders such as asthma.
Dendritic Cells and Monocytes with Distinct Inflammatory Responses Reside in Lung Mucosa of Healthy Humans
Authors: Baharom Faezzah , Thomas Saskia , Rankin Gregory , Lepzien Rico , Pourazar Jamshid , Behndig Annelie F. , Ahlm Clas , Blomberg Anders , Smed-Sörensen Anna
Published: May 2016

Every breath we take contains potentially harmful pathogens or allergens. Dendritic cells (DCs), monocytes, and macrophages are essential in maintaining a delicate balance of initiating immunity without causing collateral damage to the lungs because of an exaggerated inflammatory response. To document the diversity of lung mononuclear phagocytes at steady-state, we performed bronchoscopies on 20 healthy subjects, sampling the proximal and distal airways (bronchial wash and bronchoalveolar lavage, respectively), as well as mucosal tissue (endobronchial biopsies). In addition to a substantial population of alveolar macrophages, we identified subpopulations of monocytes, myeloid DCs (MDCs), and plasmacytoid DCs in the lung mucosa. Intermediate monocytes and MDCs were highly frequent in the airways compared with peripheral blood. Strikingly, the density of mononuclear phagocytes increased upon descending the airways. Monocytes from blood and airways produced 10-fold more proinflammatory cytokines than MDCs upon ex vivo stimulation. However, airway monocytes were less inflammatory than blood monocytes, suggesting a more tolerant nature. The findings of this study establish how to identify human lung mononuclear phagocytes and how they function in normal conditions, so that dysregulations in patients with respiratory diseases can be detected to elucidate their contribution to immunity or pathogenesis.
A comparative study on four different transmission lines in LTCC for 60 GHz applications
Authors: Isapour A. , Bahloul D. , Kouki A. B.
Published: May 2016

The wireless telecommunication systems have an undeniable role in today's society. The rapid progress of wireless services and applications accelerates demands for high data-rate reliable systems. The 60 GHz band with its 5 GHz globally unlicensed available spectrum, provides a great opportunity for the next generation of high data-rate wireless communication. Despite this attractive bandwidth surrounding 60 GHz, there are still many challenges to be addressed such as the loss performance and the integration with other systems. Low Temperature Cofired Ceramic (LTCC) technology, with its unique and mature multilayer fabrication process, has excellent capability of realizing miniaturized 3D low loss structures to overcome these challenges. Since, one of the key components in any communication system for both interconnecting and designing components is Low loss transmission lines, in this article we overview the performances and challenges for four different most practical transmission lines at 60 GHz in LTCC: Microstrip, Stripline, Coplanar Waveguide (CPW), and LTCC Integrated Waveguide (LIW).
Solutions for thermally mismatched brazing operations for ceramic tokamak magnetic sensor
Authors: Jacq Caroline , Maeder Thomas , Ellenrieder Benoit R. , Windischhofer Philipp , Jiang Xinyue , Toussaint Matthieu , Testa Duccio , Ryser Peter
Published: May 2016

To monitor high-frequency fluctuations of the equilibrium magnetic field in tokamaks, a 3D magnetic sensor has been developed. The sensor, which is positioned inside the vacuum vessel behind the protective tiles of the tokamak and is exposed to potential temperatures up to 400°C, is based on thick-film and LTCC (low-temperature co-fired ceramic) technology. To connect the sensor to the cabling that runs inside the vacuum vessel, mineral-insulated cables have to be brazed to the sensor to ensure electrical connection together with mechanical robustness and sufficient thermal stability. As the brazing temperature is about 600°C, direct brazing to the alumina sensor substrate can cause failure by cracking induced by thermal stresses. It arises both by temperature gradients stemming from the localised heating and by the high thermal mismatch of alumina with the braze and wire materials. In previous work, high stresses from temperature gradients were efficiently decoupled by brazing indirectly to alumina beams attached to the main substrate, and local thermal stresses between alumina and braze/wire by using a porous metallisation. However, as the slender alumina beams protruding out of the substrate are somewhat cumbersome and fragile, three alternatives were studied in the present work: 1) testing shorter and more robust beams, 2) replacing the alumina beam by a silver wire, and 3) depositing a porous temperature- and stress-decoupling dielectric to enable direct brazing on the main alumina substrate. These solutions are characterised with respect to their mechanical robustness and of the degree of thermal decoupling with the substrate they provide.
Multilayer Ferrite Inductor Substrate for Ceramic-Based High Current Point-of-Load (POL) Converter
Authors: Zhang Wenli , Su Yipeng , Lee Fred C.
Published: May 2016

High power-density and high efficiency are the two driving forces for point-of-load (POL) converters used in portable electronics and other applications where system miniaturization is required. Discrete passive components, especially bulky inductors, have become the bottleneck for downsizing POL converters. Low-temperature sintered Ni-Cu-Zn ferrite tapes for multilayer chip inductors have been widely studied and used in high-frequency power electronics applications. In our previous study, a low-profile, planar inductor substrate with lateral flux pattern was fabricated using mixed commercial low-fire Ni-Cu-Zn ferrite tapes and compatible low temperature co-fired ceramic (LTCC) processing. However, thermal interface material was used between active circuit board and passive layer (ferrite substrate), which increases the total volume of the converter and becomes a potential threat for reliability due to the mismatch of coefficient of thermal expansion among different layers. Additionally, this hybrid integration method requires labor-intensive manual steps which are not compatible with cost-sensitive power electronics market.

A fully ceramic-based POL module with integrated multilayer ferrite inductor has been proposed. The circuit and other components are designed to be directly built on top of the multilayer ferrite inductor substrate. This presented work focuses on the development of the multilayer ceramic substrate with embedded planar, lateral-flux inductor by co-firing of ferrite and dielectric tapes with conductor paste. Commercial dielectric LTCC and ferrite tapes were chosen for the fabrication of multilayer ferrite inductor substrate. Different silver pastes were co-fired with ceramic tapes to form the inductor winding. The sintering behavior and compatibility of dielectric, magnetic, and conductive components in one co-firing process was studied in order to realize a cohesive multilayer ceramic substrate. The embedded inductors present lower inductance than pure ferrite inductors sintered alone using the same profile when the output current is smaller than 10 A. The inductance of both types of inductors are very similar when output current is above 15 A. The inductor embedded in dielectric tapes exhibits higher core loss density than its counterpart. Future work will focus on the integration of high current POL module using this developed multilayer ferrite inductor substrate.
LTCC Breakdown Voltage Investigation
Authors: Dorczynski Mateusz , Fabinska Wiktoria , Roguszczak Henryk , Golonka Leszek
Published: May 2016

High voltage properties of the LTCC (Low Temperature Co-Fired Ceramics) cofired ceramic tape are presented. Chauvin Arnoux C.A. 6555 insulation tester is used to measure the leakage current and the resistance. Measurement is possible up to 15 kV. The DuPont 951 test structures are manufactured. The electrodes are fabricated of Ag (DP 6142) and PdAg (DP 6146) pastes. The leakage current dependence upon the temperature up to 320°C is measured. The ceramics properties depend on the temperature, especially beyond 200°C. Moreover, the current characteristics as a function of electrical field are presented and the breakdown voltage is determined.
MEMS Fabrication on LTCC Substrates for RF Applications: Challenges and Perspectives
Authors: Bahloul Dorra , Amar Achraf Ben , Kouki Ammar B.
Published: May 2016

Microelectromechanical Systems (MEMS) are often used in transceiver modules, especially for telecommunication and radar applications. In this paper, we present recent progress in the development on a MEMS-on-LTCC process. We focus on the Low Temperature Co-fired Ceramic (LTCC) substrate issues and we present a successful solution for overcoming the substrate challenges through surface pre-treatment using a chemical mechanical surface polishing (CMP) process which allows us to reach the required smoothness for the fabrication of MEMS devices. We discuss various process parameters such as slurry type, rotating pad and rotation speed, and show their impact on the final surface finish. With an optimized process, the maximum roughness was decreased from more than 10μm to less than 0.5 μm over a 640 × 640 μm2 LTCC sample. Also, we present the various MEMS process steps starting with the deposition and patterning of various layers to a prototype switch highlighting the validated steps and the challenges encountered. A brief discussion of the perspectives for the integration of MEMS and LTCC technologies is also presented.
High Resolution LTCC Laser Processing in the Green and Fired State for Future Technologies
Authors: Gutzeit Nam , Welker Tilo , Drüe Karl-Heinz , Müller Jens
Published: May 2016

In this publication the results of laser structuring processes of LTCC substrates, screen printed and laser structured gold thick film lines and the processing procedures are presented. To investigate the compatibility of the laser processes into the conventional LTCC process chain the laser structuring was done in green as well as in fired state. Typical easy electrical patterns like miniaturized interdigital structures and meanders serve as examples of the reached resolution and geometrical borders of the laser structuring techniques at the Center of Micro- and Nanotechnologies of the TU Ilmenau (IMN Macro Nano®). The lateral precision and the topological shape are determined by laser scanning microscopy. The aimed structures have lines and spaces of 30 μm. A statistical evaluation is done to show the possibilities and the limits of the new laser structuring processes with picosecond UV laser ablation systems.
Integrated Microchannel Cooling for Power Electronic Modules
Authors: Zhang Wenli , Yang Fengchang , Qiao Rui , Boroyevich Dushan
Published: May 2016

The power electronic module plays a key role in the power system by providing the needed physical support, electrical contact and insulation, and thermal pathway for power devices. Using wide bandgap power semiconductors in the power modules enables high-frequency and low-loss switching at relatively high temperatures for efficient power conversion. These advantages could lead to an increase in power-density for the power module as well as a reduction of cost, weight, and volume at the system level. However, the highly integrated power module requires advanced thermal management solutions for effective heat removal from the active chips to achieve high reliability. The evaluation of thermal performance for the power module is critical for its packaging design, because most of the heat generated by the semiconductors is dissipated through the module package. It is even more critical for the gallium nitride (GaN)-based power modules due to the lower thermal conductivity of the GaN material compared with that of silicon and silicon carbide.

This paper provides a brief introduction of power modules in conventional packaging design and a review of several new packaging structures with advanced thermal management solutions. The direct-bonded-copper (DBC) substrate with integrated microchannel cooling designed for a new packaging structure is proposed for highly integrated power modules. In this design, the cooling microchannels are embedded inside the aluminum nitride (AlN) layer of the DBC substrate. In finite element analysis (FEA) simulation model of the new package, six high-voltage GaN transistors are arranged on the top surface of the DBC substrate to realize a three-phase inverter circuit. Three straight embedded microchannels with a cross-sectional area of 0.3 mm × 5 mm are located underneath the GaN devices. The average maximum temperature of the GaN devices in the new package is around 72 °C (50 W power loss applied on each die), which is about 16 °C lower than that in the traditional power module package. A thermal transfer coefficient of 2000 W/m2 K, which is equivalent to the liquid cooling condition, is applied on the bottom surface of the baseplate in the traditional package. Enhanced heat dissipation capability is demonstrated using this integrated microchannel cooling method. Further study will focus on the fabrication of a prototype and experimental testing.
LTCC Thick Film Process Characterization
Authors: Girardi M. A. , Peterson K. A. , Vianco P. T.
Published: May 2016

Low temperature cofired ceramic (LTCC) technology has proven itself in military/space electronics, wireless communication, microsystems, medical and automotive electronics, and sensors. The use of LTCC for high frequency applications is appealing due to its low losses, design flexibility and packaging and integration capability. The LTCC thick film process is summarized including some unconventional process steps such as feature machining in the unfired state and thin film definition of outer layer conductors. The LTCC thick film process was characterized to optimize process yields by focusing on these factors: 1) Print location, 2) Print thickness, 3) Drying of tapes and panels, 4) Shrinkage upon firing, and 5) Via topography. Statistical methods were used to analyze critical process and product characteristics in the determination towards that optimization goal.
A Unified ASIC and LTCC Module Design Kit for High-Temperature High-Density Circuits
Authors: Holmes Jim , Francis A. Matthew , Getreu Ian , Glover Michael
Published: May 2016

State of the art high temperature ASIC design requires the complement of high temperature modules and circuit boards. Certain LTCC tape systems have coefficients of thermal expansion that are well matched to advanced high temperature semiconductors such as SiC, making them an attractive option for low to mid-volume high temperature products.

A computer aided process design kit that supports unified design of high temperature SiC ASICs and the corresponding LTCC module is presented herein. The CAD tools used in the design kit are open source and include basic features such as schematic capture layout drafting, design rule checking, and schematic to layout equivalency checking. In addition, advanced features are included such as automatic routing, automatic pad frame generation, and parasitic extraction for high-fidelity simulation. The kit also allows for the generation of a 3D mock-up rendering of the ASIC and LTCC co-design. Most importantly, pattern file generation for ASIC and LTCC manufacturing data formats is supported. Revision control is also easily accomplished, making collaboration within large design teams tractable. A 12-Volt high-temperature amplifier design using a SiC ASIC process and a compatible LTCC process is presented as a case study.
Co-selection of antibiotic and heavy metal resistance in freshwater bacteria
Authors: Di Cesare Andrea , Eckert Ester , Corno Gianluca
Published: May 2016

Antibiotic resistant bacteria are found in most environments, especially in highly anthropized waters. A direct correlation between human activities (e.g., pollution) and spread and persistence of antibiotic resistant bacteria (ARB) and resistance genes (ARGs) within the resident bacterial communities appears more and more obvious. Furthermore, the threat posed for human health by the presence of ARB and ARGs in these environments is enhanced by the risk of horizontal gene transfer of resistance genes to human pathogens. Although the knowledge on the spread of antibiotic resistances in waters is increasing, the understanding of the driving factors determining the selection for antibiotic resistance in the environment is still scarce. Antibiotic pollution is generally coupled with contamination by heavy metals (HMs) and other chemicals, which can also promote the development of resistance mechanisms, often through co-selecting for multiple resistances. The co-selection of heavy metal resistance genes and ARGs in waters, sediments, and soils, increases the complexity of the ecological role of ARGs, and reduces the effectiveness of control actions. In this mini-review we present the state-of-the-art of the research on antibiotic- and HM-resistance and their connection in the environment, with a focus on HM pollution and aquatic environments. We review the spread and the persistence of HMs and/or ARB, and how it influences their respective gene co-selection. In the last chapter, we propose Lake Orta, a system characterized by an intensive HM pollution followed by a successful restoration of the chemistry of the water column, as a study-site to evaluate the spread and selection of HMs and antibiotic resistances in heavily disturbed environments.
Catchment liming creates recolonization opportunity for sensitive invertebrates in a smelter impacted landscape
Authors: Gunn John M. , Kielstra Brian W. , Szkokan-Emilson Erik
Published: May 2016

The response of a sensitive indicator species to the effects of catchment liming was assessed in a lake severely impacted by atmospheric emissions from a metal smelter in Sudbury, Canada. The lake chemistry recovered following the closure of the local smelter and major reductions (approximately 95%) in acid and metal emissions from other area smelters, leading to recolonization of the lake with fish and other biota. However, the littoral macrobenthos community remain severely impoverished. The catchment liming sustained improved stream water quality for 20 years after the initial aerial treatment and created a littoral zone hot spot for the recolonization of Hyalella azteca. Colonization at delta sites of untreated catchment drainage areas, in the same lake, were low and highly variable, and these sites appeared to be impacted from soil erosion and episodic release of acid and metals. This study demonstrated the need to both reduce air pollutants and to conduct land reclamation in severely damaged watersheds, before lake ecosystems themselves can be fully recovered.