bluuebunny/crossref_metadata_2025 huggingface dataset:
The Malaysian Polypropylene Industry Outlook In Facing ASEAN Free Trade Area (AFTA) Deregulation
Authors: Ismail Ahmad Zaki Bin Hj. , Selamat Sarun Bin , Ahmed Elsadig Musa
Published: March 2016

The objective of this study is to focus specifically on the Malaysian polypropylene industrys performance in order to further understand the current situation. As the future of the plastics industry is becoming more competitive due to the uncertainties of the global economy, it is hoped that this study could help to assist the Malaysian polypropylene industry to understand the future potential challenges better. Another aspect of the future challenges for the industry is the lifting of the trade barrier within the ASEAN countries. By early 2003, the ASEAN Free Trade Area (AFTA) has imposed in the ASEAN regions and there will be little or no tariff at all between the ten ASEAN countries. Based on the surveys results, the Malaysian polypropylene industry is still very much dependent on the domestic market. The overall domestic market share commands about 60% of the total business. The trend to expand the export market is still in progress and in line with the overall Malaysian plastics industry. At the moment, only the large polypropylene industries are very aggressive in capturing the export market. If the current market segmentation of the overall industry is maintained, the AFTA deregulation could affect the future outlook of the industry as the alternative domestic market is not available in time in case of any penetration happens to this major market segment. As the small and medium polypropylene industries are very much dependent on the domestic market, they could be the first segment of the industry that would face the immediate effect or challenges of AFTA to the industry.
Educating Business Professionals For Year 2010 And Beyond: Six Critical Management Themes And Skills To Emphasize
Authors: Akbari Hamid
Published: March 2016

In this paper, based on the recent global and technological developments, I propose six critical themes/skills which need to be given a substantially more emphasis and coverage for educating business professionals in management for year 2010 and beyond. While there is interdependence among these six themes, they are separated for the reasons of focus and understanding.
The Cultures Of International Management
Authors: Gonzalez Carlos B.
Published: March 2016

In this paper I present an approach based on Cultural Studies to conceive of and pursue cultural inquiry in international management. For this purpose, I first develop a genealogical framework for understanding how the international management literature has engaged with culture over the past forty years. This framework focuses on decisions that international management scholars have made as they attempt to address culture in their research. It also focuses on the consequences of these decisions, which have skewed the field towards certain intellectual positions and have maintained culture as a problematic concept. In the last section I present an alternative approach situated within Cultural Studies to address the problem of culture in international management scholarship.
Comparing Monetary And Fiscal Policy Transmission Across The Americas And The Emu-Area
Authors: Tsoukalas Dimitrios
Published: March 2016

This paper estimates structural VAR models to compare the transmission mechanism of monetary and fiscal policy in the Americas and the EMUarea countries. First, the NAFTA countries are considered and the estimation results are compared with those for the EMU-area countries. Attention is also paid to interaction of macroeconomic policies and the effects of shocks in financial markets. Results show that the Americas except for the U.S. and Canada react rather differently to monetary and fiscal policy shocks than the EMU- area countries.
Intra-day Trading Volume Patterns Of Equity Markets: A Study Of US And European Stock Markets
Authors: Ozenbas Deniz
Published: March 2016

We investigate the pattern of intra-day volume of trading in five different equity markets: The New York Stock Exchange and NASDAQ in the US, and The London Stock Exchange, Deutsche Boerse, and Euronext Paris in Europe. For the European markets, we repeat our investigation for two separate study periods to check for the consistency of our results and also to account for important rule changes that took place in the middle of the year in those markets. For the US markets, the intra-day pattern of volume is a reverse J-shape, consistent with previous literature. On the other hand, for all the European markets, volume is quite low at the open and picks up towards the end of the trading day. The most striking case is the London Stock Exchange, where, at the beginning of the day, the volume is the lowest across all markets studied. Additionally, we find that the rule changes in the European markets pertaining to introduction of call auctions, and extension of trading hours met with mixed success.
Examining The Day Of The Week Effect In Istanbul Stock Exchange (ISE)
Authors: Cinko Murat , Avci Emin
Published: March 2016

The existence of day of the week effect for Istanbul Stock Exchange (ISE) was analyzed on the basis of ISE-100 index returns, the returns of all stocks traded in ISE and market capitalization based portfolio returns during 1995-2008. In line with the previous findings, the results of the study presented that the ISE-100 index, ISE traded stocks and market capitalization based portfolios had significant negative Monday and significant positive Thursday and Friday returns.
The New Strategic Imperative: Understanding the Female Business Traveler
Authors: Newth Francine
Published: March 2016

This paper explores the characteristics, needs, and behaviors of women who travel on business and analyzes the data for potential segmentation. The study focuses exclusively on the female business traveler. The sample consists of 235 female business travelers from a variety of industries. The statistical methods include correlation analyses, factor analysis, and cluster analysis. The findings show that 6 factors explain 60.4% of the variance in characteristics, behaviors and needs of female business travelers. Cluster analysis further identifies 3 clusters: the Connective, the Empowered, and the Productive. The results show that there are three distinct types of women who travel on business. Strategies are suggested for organizations to use the findings to respond to female business travelers.
Career Competencies And Career Success Of Thai Employees In Tourism And Hospitality Sector
Authors: Lertwannawit Aurathai , Serirat Sirivan , Pholpantin Siroj
Published: March 2016

This research assesses the relationship between career competencies and career success of Thai employees in the tourism and hospitality sector. The authors distinguished and operationalized four career competencies, i.e. computer and language skills, work spirits and ethics, team working and leadership, and tourism and hospitality knowledge and skills, and two career successes, i.e. objective and subjective career successes. A quantitative study was performed using 800 employees in four industries, i.e. restaurant, hotel, travel and tour operation, and airline business. Pearson correlation and regression analyses were used to analyze data. The results indicate that career competencies have moderately positive relation with career success. Furthermore, three career competencies, i.e. computer and language skills, team work and leadership, and tourism and hospitality knowledge and skills have effect on career success. The results are discussed with respect to facilitate organizations training programs, which enhance employees career success.
Age Distribution Model For GCC Countries
Authors: Rahman Shafiqur
Published: March 2016

Efficient and reliable estimates of the proportions of population at different age levels are essential for making quality budget of any developing or developed nation. These estimates are obtained from the best-fitted age distribution model and can be used to find the number of school age children, number of pensioners etc. Past population census data of GCC countries are analyzed to find the best-fitted age distribution model applying chi-square goodness of fit test and model selection criteria and observed that the age distribution of most of the GCC countries is exponential. A comparative study of the age distributions of six GCC countries with some developed countries is also provided.
Service Quality of On-Campus Student Housing: A South African Experience
Authors: Radder Laetitia , Han Xiliang
Published: March 2016

This study adds to the service quality literature on student housing, particularly within a South African context. The study proposes and confirms a modified model of SERVQUAL and assesses the quality of on-campus student housing at a South African university based on 430 respondents expectations and perceptions. Exploratory, first- and second-order confirmatory factor analyses performed as part of the data analysis confirmed that on-campus student housing service quality can be viewed as a second-order construct defined by four first-order dimensions: interaction, empathy, general amenities, and room amenities. T-tests and ANOVA tests show that neither age nor gender relates significantly to service quality perceptions. The data also reveal a four-tier structure of service quality which can guide residence managers in allocating limited resources to those service dimensions students regard as most important, but least satisfactory.
The Realms Of Knowledge Management From An Organizational Perspective
Authors: Wajidi M. Abu Zar , Asim Muhammad
Published: March 2016

The international scenario of industrial competitiveness has tremendously transformed during the last few decades. Organizations competing in the global economy are facing different challenges in order to survive and make progress. The rapid advancements in computer technology, emergence of the internet, World Wide Web, and telecommunication devices have profoundly affected the activities of business organizations. These trends have forced the organizations to reshape and redefine their economic and business strategies. This factor can be counted as the knowledge boom which, in todays developed world, is more appropriately referred to as the knowledge management. Knowledge Management is one of the burning topics nowadays, which has brought significant changes in organizations in developed countries and gave new impetus for global competition and new challenges for the organization in developing countries. This paper aims at providing a ground work for organizations in developing countries. It will help organizations provide a framework for contribution to knowledge management aspect and also enable organizations in developing countries, especially large organizations intending to globalize their operations, to analyze their position and design a future strategy accordingly.
The Role Of End-User Training In Technology Acceptance
Authors: Marshall Bryan , Mills Robert , Olsen David
Published: March 2016

The purpose of this paper is to examine the role end-user training has on performance expectancy and effort expectancy, two variables associated with technology acceptance. The technology-based elements of the HIPAA security rules among oral surgeons were used for the study. The method of the investigation was a cross-sectional correlational study using a self-reported mailed questionnaire. The survey was created using preexisting scales from the Unified Theory of Acceptance and Use of Technology. Results suggest end-user training is positively correlated with both performance expectancy and effort expectancy.
Neural Networks In Business Time Series Forecasting: Benefits And Problems
Authors: Zhao Lin
Published: March 2016

Many studies examine the use of Neural Networks (NNs) as a tool for business time series forecasting, but the findings have been mixed and inconsistent. This paper explores the conditions under which NNs can improve business time series forecasting based on studies that compare NNs with traditional statistical models. The findings are that NNs generally outperform alternatives when data are nonlinear or discontinuous, building effective NNs for time series forecasting, including designing and selecting the structure, simulation functions, stopping rules, training algorithms and evaluation criteria remains challenging. A case study is discussed to illustrate these findings, and implications for future research and practice are also provided.
An Integrated Approach To Teaching Web Development
Authors: Hauser Karina , Olsen David , Fadel Kelly
Published: March 2016

The growing use of the Internet has led to a steep increase in the demand for web developers who possess web design, database, and programming skills.  The demand for these skills is reflected in the new IS2007 model curriculum, which suggests that web developers obtain in-depth knowledge of databases and web programming. While these topics are commonly covered in Information Systems (IS) curricula, they are traditionally taught independently in separate courses, leaving students with a fragmented view of how to integrate the various components of a data-driven web application.  Research on learning has shown that activation of existing knowledge is an important step in the learning process. This study shows how a common business case can be used to support the activation of existing knowledge in different classes related to web development. The detailed examples show how to use the same business case to teach database, web design, and programming skills.
What Is Important When Shopping Online?
Authors: McKinzie Kaye , Griffin Ken , Cantrell Pat , Chen Vicky
Published: March 2016

Shoppers have many avenues on where to purchase products, one of which is online. Many online retailers do not apply state and local sales taxes on products they sell, thus allowing them to sell their products cheaper than can be found at local retailers. If the physical presence nexus rule is altered and Internet sales tax is applied for all online transactions, it could potentially change online shopping. The results of a survey of 154 persons are presented, discussing the potential impact of the changing of the physical presence nexus rule and requiring Internet sales tax.
Marketing And The Rise Of Web 2.0: Expanding Opportunity, Increasing Challenge
Authors: Rosen Peter A. , Phillips Mark H.
Published: March 2016

As the Internet has become an increasingly central element of daily life, marketers have scrambled to adapt their methods to this new medium. While early online marketing efforts consisted primarily of repackaged print materials, the rise of Web 2.0 sites with their increasingly interactive experiences has forced marketers to broaden their offerings in order to remain relevant. This analysis considers the broad dimensions of the new online marketing landscape. It assesses the major Web 2.0 sites and evaluates their current scope and reach, concluding that firms utilizing Web 2.0 tools for marketing purposes must insure consistency across their various sites, invest adequate resources to provide prompt service, and recognize that customer expectations for such service will continue to rise for the foreseeable future.
Evolution Of Fair Business Performance As A Tool Of Marketing In Spain
Authors: Cordente-Rodriguez Maria , Mondejar-Jimenez Juan-Antonio , Gazquez-Abad Juan-Carlos
Published: March 2016

Although the distance communication systems have been developed in the last years thanks to the development of communication and information technologies, recent studies argue that simple ways of communication like fairs maintain and increase their weigh cause of their profitability. In this way the fairs represent an important communication platform, whose use is generalized in the all economic areas. The aim of this paper is analyze the evolution of fair business in Spain, in the period 2002-2009, to solve two important questions which revolve about the efficiency of this communication tool and its power to maintain and establish new business relationship. For this, this paper analyzes the main characteristics or indicators of fair business, such as number of celebrated events, areas of interest, number of exhibitors or the number of attendees, from the information of Spanish Association of Fairs.
Do You Have Social Profile? Users And Non-Users Of Social Networking Sites In The Web 2.0
Authors: Lorenzo-Romero Carlota , Alarcon-del-Amo Maria-del-Carmen , Gomez-Borja Miguel-Angel
Published: March 2016

In light of the increasing importance of Social Networking Sites (SNSs) for both personal and professional relationships, the aim of this work is to contribute to the knowledge framework regarding the interactive behaviour of Internet users, particularly within Web 2.0, describing its evolution from Web 1.0. Moreover, this paper analyses the different behaviours on the Web by people who use or not use SNSs, as well as to determine whether any such differences are significant in order to discover the reasons why these people participate. As results, initial characterization of the users themselves is followed by an analysis of the main differences between users and non-users of these applications. With this information, companies can play an active role in this Social Web by becoming company 2.0 and participating actively in already existing SNSs or creating their own social network service.
Violence Against Women: The Treatment In The Spanish Criminal Law
Authors: Ochaita Silvia Valmana
Published: March 2016

In the last years we have been witnesses of how the legal reforms about gender violence have been followed one another in Spain, and how they were fruitful in the social conscience. Nevertheless, the legal effectiveness of the reforms is still questioned, the judicial decisions often are contradictory, and the violence level is greater than ever or, at least, more visible. This work tries an approach to the study of this matter throw the legislative evolution, analyzing the lights and shadows of the Spanish Criminal System.
The Association Between Fundraising Efficiency, Financial Vulnerability, And Subsequent Donations To Not-For-Profits
Authors: Surysekar Krishnamurthy , Turner Elizabeth H.
Published: March 2016

In this paper, we empirically study the association between past year fundraising efficiency and current year donations to not-for-profit organizations. First, our data show that prior year fundraising inefficiency (fundraising expenses as a proportion of total donations) is negatively associated with current year donations and is robust to an inclusion of prior year financial vulnerability as an explanatory variable. Secondly, we find that prior year levels of fundraising expenses and program expenses are positively associated with current year donations. Finally, prior-year financial vulnerability, which is measured in our paper consistent with Greenlee and Trussel (2000), is negatively associated with current year donations.
IT Knowledge: What Do Accounting Students Think They Know? Do You Know More Than I Do? An Exploratory Study
Authors: Strong Joel , Portz Kris
Published: March 2016

In recognition of the growing role of information technology (IT) in teaching accounting, we surveyed students at three Midwestern universities to determine their self-reported knowledge levels of 36 specific information technologies and difference in those IT knowledge levels between universities.  Unlike other areas of accounting, there are no set standards for the IT curriculum for accounting education.  Because of this, we expect to find significant differences in IT knowledge between these three universities.  These findings are analyzed in light of authoritative guidance on appropriate accounting technology topics and research on the current status of IT in accounting education.  We find accounting students have a low level of self-perceived IT knowledge.  These students are not proficient in requisite technologies even after completing most of their undergraduate course work.  We also find that there are significant differences in IT knowledge between the three universities in the study.  These findings imply that we may be doing a disservice to accounting students and the accounting profession by not having a set IT curriculum.  We conclude that it is time to assess IT knowledge and IT skill requirements necessary for accounting students and develop a standard IT curriculum in accounting education.
Let Your Students Have A Piece Of The Action: Real World Projects For AIS Courses
Authors: Lenk Margarita Maria
Published: March 2016

This paper describes a variety of accounting information systems projects that send students into the business world. The projects are easy to organize and are consistent with AECC recommendations. The students acquire and enhance their research, communication, creativity, teamwork and technology skills. Exit interviews have indicated many benefits to all parties involved.
The Role Of External Review Agents In Information Systems Disaster Recovery Planning (DRP) In Community-Based Institutions
Authors: Dreher Felix F. , English John B.
Published: March 2016

A survey of credit unions, school districts, and hospitals provided a sample of computer users subject to external financial, regulatory, and accreditation reviews in which DRP1 is considered an essential part of the process. This study examined the perceptions of top-level managers in these three institutions toward the role of external review agents in increasing the awareness of management to their responsibilities in DRP. The findings indicate that the managers surveyed perceive the influence of external DRP review agents to be relatively unimportant. This attitude represents a stark deviation from the recommendations provided in current DRP research literature.
Developing a Data Warehouse: Some Guidelines and Suggestions
Authors: Curtis Mary B. , Joshi Kailash
Published: March 2016

Although accounting information systems (AIS) are an important source of information for strategic development, the systems possess overriding limitations. Data Warehousing (DW) has emerged as an important tool to overcome these limitations by making use of existing data storage and database management technologies to organize the storage of relevant corporate data spanning several sources and time periods into one central location. Because DW projects are risky and expensive undertakings, however, care must be taken in their planning and development. This paper includes recommendations for the successful implementation of a DW project, addressing effectiveness, efficiency, and security issues.
Early Employment Experiences Of Accountants: Initial Placement, Job Satisfaction, And Migratory Patterns
Authors: Larkin Joseph M. , Leauby Bruce A. , Hiltebeitel Kenneth M.
Published: March 2016

Issues Statement No. 4 from the Accounting Education Change Commission (AECC) addresses the early employment work experiences of accountants. The AECC recommends a number of actions supervisors can employ to improve the job satisfaction of entry-level accountants. The current study examines the correlation between supervisory actions and job satisfaction of accountants employed by the Big-5 and accountants employed in non-Big-5 positions, private industry, governmental positions and not-for-profit organizations. Initial job placement and migratory patterns are also examined from a sample of 532 recent graduates from three universities.
A Sales Processing Simulation Exercise And Database For The Accounting Information Systems Course
Authors: Bagranoff Nancy A. , Cashell James
Published: March 2016

This paper presents a classroom simulation of a sales processing system, with an inter-active database, that was designed to enhance the learning of several important con-cepts in the introductory accounting information systems course. The experience of actually participating in the business process and interacting with the database can help students achieve a better understanding of business processes, internal control concepts, data modeling, and database software. Educational research suggests that simulations are an active teaching strategy that can be effective in teaching factual course material, and that they help stimulate students interest in the classroom expe-rience. As designed, the exercise illustrates selected system and control weaknesses that should foster critical thinking and discussion. Additionally, the database is built on the REAL model and provides students with a working example as they later learn to design and develop databases themselves.
Implementation Of Enterprise Resource Planning In Business Curriculums
Authors: Neureuther Brian D.
Published: March 2016

SAP, the most pervasive enterprise resource planning software package in the world, is currently being used in several universities across the US. The use of this software varies from institution to institution, primarily by the degree in which it permeates the business curriculum. From a personal perspective, the author seeks to examine why SAP is fully integrated in some curriculums and why it is sporadically used in other curriculums. The question of how SAP can be successfully implemented into the business curriculum is addressed and explained.
Towards an automatic model transformation mechanism from UML state machines to DEVS models
Authors: González Ariel , Luna Carlos , Cuello Roque , Pérez Marcela , Daniele Marcela
Published: March 2016

The development of complex event-driven systems requires studies and analysis prior to deployment with the goal of detecting unwanted behavior. UML is a language widely used by the software engineering community for modeling these systems through state machines, among other mechanisms. Currently, these models do not have appropriate execution and simulation tools to analyze the real behavior of systems. Existing tools do not provide appropriate libraries (sampling from a probability distribution, plotting, etc.) both to build and to analyze models. Modeling and simulation for design and prototyping of systems are widely used techniques to predict, investigate and compare the performance of systems. In particular, the Discrete Event System Specification (DEVS) formalism separates the modeling and simulation; there are several tools available on the market that run and collect information from DEVS models. This paper proposes a model transformation mechanism from UML state machines to DEVS models in the Model-Driven Development (MDD) context, through the declarative QVT Relations language, in order to perform simulations using tools, such as PowerDEVS. A mechanism to validate the transformation is proposed. Moreover, examples of application to analyze the behavior of an automatic banking machine and a control system of an elevator are presented.
Structural Transformation and Economic Diversification in West African Countries
Authors: YILMAZ Mesut , OSKENBAYEV Yessengali
Published: March 2016

In the history of modern trade theory, the capitalized countries set up ridiculous pretensions as specialization for being an industrialized country. Thus, well-know words according to their idea is “Africa has a strong comparative advantage in natural resources, so, they should specialize on them.” But today, new theories on over-specialization are to keep away commodity dependent countries from specialization. As mentioned above, there are many new concepts which are not available for Africa continent. In this article, new concepts such as Natural Curse Arguments (paradox of plenty), Dutch Disease, Immiserising Growth, windfall gain argument and over-specialization were discussed.
Macroeconomic Determinants of Industrial Development in Nigeria
Authors: AIYEDOGBON John O. , ANYANWU Sarah O.
Published: March 2016

The paper focuses on the impact of macroeconomic determinants on industrial productivity in Nigeria for the period, 1981-2013. It was discovered that while the Nigerian government had embarked on a number of industrial development strategies with the sole purpose of boasting industrial productivity in Nigeria, they seem to have yielded little or no result. The macroeconomic variables in the study include industrial production index, exchange rate, consumer price index, interest rate, broad money supply, foreign direct investment, credit to manufacturing sector and gross domestic product. The study employed OLS technique and found that exchange rate exert significant positive impact on industrial productivity in Nigeria.  Also, the impact of interest rate, FDI and real GDP on industrial production index is positive. On the other hand, consumer price index, broad money supply and credit to manufacturing sector exert negative impact on industrial development in Nigeria. The paper recommended that a workable M2 that can enhance credit to manufacturing sector and at the same time control interest rate to boast investment should be determined.
Totems and Pantheons: Paradigmatic Muses in Achebe’s Poetry
Authors: OKOYE Chike , ASIKA Ikechukwu Emmanuel
Published: March 2016

Poetry is arguably the most ancient, direct and forceful genre of literature; whether written or oral. African’s foremost novelist and widely acclaimed father of literature, Nigeria’s Chinua Achebe, is mostly known for his prose works, especially the novel Things Fall Apart. Little comparatively, is known of his poetry. But the fact remains that Achebe is a good poet as he is widely recognized as a good novelist. Although the scale of preference tilts more to his prose works than poetry nevertheless; he made lasting impressions and remarks with his poems which are worthy of note. The collection, Beware Soul Brother exists to bear testimony on the personality of Achebe as a poet and what poetry achieves in society. Incidentally, his collection of poems, Beware Soul Brother is a veritable and worthwhile corpus of his characteristic package of Igbo lore, reminiscences, experiences and unique writing style; in the grand genre of poetry. Select poems in the collection make deft use of Igbo religious and cultural tenets which Achebe the poet masterfully weaves as muse, paradigm and cultural rooting in order to portray the Igbo cosmology and worldview. This paper explores his art and style in presenting the gods, totems and guiding ancestral wisdom of the rich, ancient lore of the Igbo. Select poems from the collection form the crux and illustrations of the thrust of this paper and demonstrates Achebe’s strong affinity with the cultural artefacts of his native custom.  The implications of these in his culture are also predicated on his poems for effectiveness and to achieve a desired goal of portraying the poet as not just purveyor of his native custom and tenets but a crusader who preaches for social restoration and the need to mend walls and build bridges after years of war and wreckages.
Avaliação em obra da resistência superficial de revestimentos de argamassa
Authors: Carasek H. , Cascudo O. , Dos Santos M. S. J. , Lemes N.
Published: March 2016

RESUMOO presente trabalho tem como objetivo avaliar, em obra, a resistência superficial à tração (RST) de revestimentos de argamassa. O ensaio para avaliação dessa propriedade ainda não é normalizado no Brasil, merecendo, portanto, estudos visando a sua futura padronização, haja vista ser a resistência superficial de um revestimento de argamassa um dos aspectos relevantes no que tange ao seu desempenho. Neste sentido, foram realizadas avaliações em duas obras de diferentes construtoras na cidade de Goiânia (estado de Goiás, Brasil), onde foram analisadas a influência do operador do ensaio, as influências do traço, local de aplicação e idade do revestimento, e a influência da ergonomia durante a produção do revestimento. Os resultados obtidos foram analisados empregando procedimentos estatísticos, tendo sido calculado o tamanho da amostra e realizadas análises de variâncias, além de correlações entre a RST e outros ensaios realizados. Como resultado, obteve-se que o tamanho da amostra compatível com a variabilidade obtida no ensaio é de 10 a 15 corpos-de-prova por situação individual de análise. Também se verificou que as variáveis estudadas (traço da argamassa, idade do revestimento e ação de intempéries) exercem influência significativa nos resultados de RST. Foram observadas correlações satisfatórias entre a RST e os resultados de ensaios de resistência de aderência (r=0,87), permeabilidade (r=0,81) e índice esclerométrico (r=0,99).
La resistividad eléctrica como parámetro de control del hormigón y de su durabilidad
Authors: Andrade C. , D’Andrea R.
Published: March 2016

La necesidad de calcular la durabilidad del hormigón ha llevado a buscar un ensayo que fuera capaz de cuantificar todas las fases del proceso desde la fabricación del hormigón hasta su curado y endurecimiento. La resistividad eléctrica como inversa de la conductividad-difusividad es una propiedad del hormigón que permite su control de forma no destructiva y por ello, accesible al autocontrol. La resistividad es un indicador del fraguado y de la resistencia mecánica, del grado de saturación del hormigón y por ello del grado de curado y de la impermeabilidad o resistencia al ingreso de sustancias agresivas en el hormigón. Finalmente tiene una relación directa con la velocidad de corrosión al indicar el grado de humedad del hormigón. Por todo ello es un parámetro que permite relacionar al microestructura con el comportamiento durable del hormigón. En el artículo se describen los fundamentos de sus posibilidades.
Revisión tratadística de las proporciones empleadas en la construcción de la estructura de la iglesia de San Juan bautista en Tiripetío, Michoacán, México. Comentarios a los resultados del análisis estructural a botareles de contrafuertes y su restauració
Authors: Bedolla-Arroyo J. A. , Martí­nez-Molina W. , Alonso-Guzmán E. M. , Briansó-Penalva J. L.
Published: March 2016

El edificio en estudio es emblemático. Se encuentra desplantado sobre un suelo arcilloso. Ha sufrido modificaciones por motivos estructurales, arquitectónicos, estéticos y funcionales. La construcción de este templo data del siglo XVI. Se construyó con mampostería de piedra natural junteada con arcilla y techumbre de madera. Su planta está conformada por una sola nave rectangular de 12 m de ancho x 50 m de largo, la cual contempla 5 contrafuertes laterales, que presentan falla estructural en sus extremos superiores e inferiores Al analizar las causas del origen de las fracturas presentes, se comprueba que el edificio se construyó de acuerdo a la geometría propuesta en diversos tratados antiguos, lo que supondría un adecuado comportamiento mecánico. Se presentan las principales conclusiones obtenidas del análisis estructural realizado a los botareles de los contrafuertes, así como del estudio de Mecánica de Suelos realizado, concluyéndose que las fracturas presentes en los botareles de los contrafuertes se deben a la inadecuada selección de la mampostería natural empleada y a un inadecuado procedimiento constructivo.
Palabras clave: fábrica; tratados; edificios históricos; contrafuertes; botareles.
Teoría y experiencias en el incremento de ductilidad de los hormigones de alta resistencia reforzados con fibras de acero
Authors: Fernández Cánovas Manuel
Published: March 2016

Las acciones de impacto y cargas impulsivas provocadas por misiles o choque de aeronaves sobre edificios de contención de reactores nucleares o sobre grandes depósitos de almacenamiento de gas licuado, o de vehículos o buques contra pilas de puentes, plataformas petrolíferas marinas, etc., o de ondas explosivas sobre edificios civiles o militares, siempre han tenido una gran importancia en ingeniería, pero las tienen más en estos últimos tiempos debido a la proliferación de actos terroristas. Las estructuras sometidas a estas acciones deben presentar un comportamiento diferente a las tradicionales debido a las grandes cantidades de energía que tienen que absorber y disipar en tiempos muy cortos, de aquí que los elementos estructurales formados por hormigón y acero, tengan que poseer una ductilidad suficiente para que mediante grandes deformaciones anelásticas no llegue a colapsar. En experiencias realizadas frente a acciones dinámicas parecidas a las provocadas por los sismos o a la acción de explosivos o de impacto de proyectiles hemos podido comprobar como el confinamiento de los elementos estructurales conseguido conarmadura tradicional y fibras de acero puede producir una ductilidad notable. Este artículo tiene por objeto presentar los resultados de algunos trabajos de investigación en los que se muestra el comportamiento de elementos de hormigón armado reforzado con fibras de acero frente a este tipo de acciones.
Palabras clave: ductilidad; impacto; cargas impulsivas; sismos; hormigón de alta resistencia; fibras de acero; cráter de salida
Tratamento de superfície com silicato de sódio para concreto: penetração de cloretos e absorção de água
Authors: Medeiros Marcelo H. F. , Pereira E. , Helene P.
Published: March 2016

Entre os tipos de tratamento de superfície para concreto, está o Na2SiO3, que reage com o NaOH presente na solução dos poros do concreto dando origem a compostos insolúveis. Este trabalho objetiva apresentar o efeito deste produto sobre o transporte de água e íons cloretos através do concreto. Para isso, são apresentados resultados de ensaios de absorção por imersão, absorção por sucção capilar e migração de cloretos. Os resultados indicam que este tratamento realmente reduz a penetração de água através do concreto, devendo intervir na cinética do processo de corrosão do concreto armado. Contudo, os resultados de absorção de água por imersão indicaram que este produto não deve ser aplicado em casos em que haja pressão de água, ou seja, o mecanismo de penetração seja a permeabilidade. Finalmente, foi demonstrado que o tratamento com Na2SiO3 reduz o coeficiente de difusão de cloretos resultando no aumento da vida útil da estrutura.
Palavra-Chave: concreto; proteção superficial; silicato de sódio; durabilidade; vida útil
Diagnóstico patológico y propuesta de intervención de los cimientos y de los muros de contención de derrames de dos tanques de almacenamiento de ácido sulfúrico para usos industriales
Authors: Dikdan M.Y. , De Corrales R. M. , Avon D.
Published: March 2016

En los muros y la losa de piso de una piscina de contención de derrames de tanques metálicos de ácido sulfúrico se evidenciaron sintomatologías de fallas. Se observó desagregación en las bases de los tanques y en la losa de piso. En la parte inferior de los muros se evidenció pérdida de conexión con la losa de piso. Mediante la extracción de núcleos al concreto se determinó: carbonatación, porosidad, penetración de sulfatos y resistencia a compresión. Al acero se le midió: espesor de recubrimiento, diámetro, potenciales y velocidad de corrosión. Se determinó la capacidad remanente del muro mediante cálculo estructural. Como conclusión la estructura se apreció muy afectada. Se recomienda el diseño especial de concreto con revestimiento antiácido y dos acciones, una inmediata mediante la construcción de tacos que garanticen apoyo y estabilidad a los tanques, y otra definitiva, reubicación del sistema de los tanques y la piscina.
Palabras clave: Tanques, Ácido sulfúrico, Desagregación, Corrosión, Muros.
La capilla del hospital “Yurhixo” en Angahuan, Michoacán, México. Su antecedente técnico – arquitectónico y su proceso de restauración
Authors: Bedolla-Arroyo J. A. , Alonso-Guzmán E. M. , Martí­nez W. , Bedolla E. , Chávez H. , Lara-Gómez C.
Published: March 2016

La antigua capilla del hospital “Yurhixo” de Angahuan, forma parte importante del contexto histórico de las construcciones edificadas durante los primeros años de la colonización española en la sierra tarasca de la región de Michoacán, México. Esta obra arquitectónica, representante de las capillas de hospital del siglo XVI, muestra la sencillez de solución arquitectónica con la que se cubrían las necesidades de evangelización en esa época.La investigación se centra en realizar un análisis y registro del inmueble, identificando las alteraciones y deterioros materiales, indicando un dictamen del estado de conservación del mismo, así como proponer una intervención del inmueble, abordando las actividades referentes a consolidación de muros de mampostería exteriores, portada de fachada principal, pisos y recubrimientos interiores, así como la restauración completa de la estructura de madera, indicándose también un proceso de restauración de la cubierta.
Palabras clave: Monumentos históricos, restauración, capilla hospital
Inspección de una losa de 70 años de un edificio en el Golfo de México
Authors: Castro-Borges P. , Balancán-Zapata M. , López-González A. , Córdova-Quintal M.
Published: March 2016

El muelle de Progreso alberga un edificio de setenta años de antigüedad, expuesto a unambiente agresivo en el Golfo de México. Debido a la exposición a cloruros y la falta demantenimiento, su losa mostró síntomas de corrosión y desprendimientos de concreto. Enuna inspección estructural previa se sugirió un costoso y poco comprensible método dereparación, lo cual hizo pensar a las autoridades portuarias en la demolición sin prever dañoscolaterales a otros elementos como columnas y vigas. Debido al nivel de deterioro, losautores de este trabajo sugirieron una segunda inspección antes de demoler, la cual se realizóen zonas representativas. El objetivo de este trabajo es discutir detalles y resultados de ésta yde la inspección previa, así como del diagnóstico, el cual indicó la necesidad de demolerpartes específicas de la cubierta inferior de la losa y la sustitución de la armadura por CFRP.Palabras clave: Inspección, reparación, cloruros, técnicas electroquímicas
Importancia de la modelación numérica en la puesta en valor de estructuras patrimoniales de mampostería en zona sísmica
Authors: González del Solar G. , Martí­n P. , Calderón F. , Maldonado N. G. , Maldonado I.
Published: March 2016

Se aplica la modelación numérica de un edificio de mampostería cerámica cocida de fines delsiglo XIX en la zona de mayor riesgo sísmico de Argentina mediante el método de loselementos finitos. Para la verificación estructural se formula un modelo no lineal, utilizandoelementos tipo shell que simulan el comportamiento no lineal de la mampostería a fin deverificar la estructura ante distintas acciones considerando el daño existente y por otro lado, seanaliza la estructura en forma lineal para diseñar y verificar el refuerzo propuesto. Para elcomportamiento del suelo se utiliza el modelo de Mohr Coulomb elasto-plástico. La validez delos resultados obtenidos implica utilizar parámetros derivados de estudios de campo ylaboratorio a escala natural, de muretes de espesores similares. La eficiencia de la puesta envalor se analiza mediante técnicas de identificación de sistemas previo a la rehabilitación yposterior a ella.Palabras clave: mampostería, gran espesor, sismo, modelación
Valorización de cenizas de lodo de depuradora como componente de hormigones para prefabricados
Authors: Baeza Brotons F. , Garcás Terradillos P. , Payá Bernabeu J. , Galao Malo O.
Published: March 2016

Se plantea la combinación binaria y ternaria de cenizas de lodo de depuradora (CLD) con ceniza volante,polvo de mármol y ceniza de cáscara de arroz, como sustitución parcial o como adición respecto al cementoPortland en hormigones, con una dosificación similar a la utilizada en la prefabricación de bloques(consistencia muy seca). Se llevaron a cabo ensayos físico-mecánicos sobre probetas de mortero yhormigón con edades de curado de 28 y 90 días: densidad, absorción y resistencia a compresión. Secomprueba que la sustitución de cemento por CLD supone una disminución de la densidad y de laresistencia respecto a la muestra patrón, sin embargo, las combinaciones con otros residuos mejorannotablemente las características de los materiales cementantes. La adición de CLD proporcionó densidadesy resistencias similares a la muestra de control y reduce significativamente la absorción de agua.Palabras claves: sostenibilidad, subproductos industriales, adiciones minerales.
Caracterización química y físico-mecánica de cementos adicionados de filer calizo en Venezuela
Authors: Bolognini H. , Martí­nez N. , Troconis de Rincón O.
Published: March 2016

En los últimos años en Venezuela, se ha presentado una crisis sobre la demanda, comercialización y producción del cemento, principal material de construcción. En este trabajo se presentará la caracterización química y físico- mecánica realizada a las principales marcas comerciales de cementos adicionados en el país, caracterizándolos de acuerdo a: composición química, finura Blaine, tiempo de fraguado y resistencia mecánica a compresión. Los resultados demuestran que estos cementos no cumplen con los requisitos mínimos establecidos en la norma venezolana para su uso en la elaboración de concreto estructural.
Palabras clave: Cemento Adicionado, Corrosión, Concreto Armado.
Terrestrial plants and marine algae from the Late Jurassic lithographic limestone of the Causse Méjean (Lozère, southern France)
Authors: Moreau Jean-David , Baret Louis , Lafaurie Gérard , Chateau-Smith Carmela
Published: March 2016

A new Late Jurassic flora was discovered in the fossiliferous lithographic limestone of the Causse Méjean, Lozère (southern France). It consists of the first Kimmeridgian/Tithonian plants from this area. Fossil plants are represented by megaremains preserved as impressions. This flora shows a co-occurrence of terrestrial plants and marine algae. The land plants include vegetative remains ascribed to bennettitaleans (Zamites Brongniart, 1828), conifers (Brachyphyllum Brongniart, 1828), and pteridosperms (Cycadopteris Zigno, 1853). Marine algae were ascribed to dasyclads (Goniolina D’Orbigny, 1850). Lithological and palaeontological features suggest preservation in a flat, homogeneous, protected environment, perhaps a brackish or marine lagoon, influenced by both continental and marine inputs. This discovery complements the few existing reports of European Late Jurassic floras, and indicates that coastal habitats were dominated by sub-arborescent vegetation, consisting of bennettitaleans and pteridosperms, and arborescent plants, such as conifers. Both the palaeoenvironmental context and certain xerophytic features suggest that these terrestrial plants from the Causse Méjean were well adapted to the hot, dry conditions of coastal areas.
Characterizing cell surface of blooming Microcystis in Lake Taihu, China
Authors: Liu Lizhen , Huang Qi , Qin Boqiang , Zhu Guangwei , Wu Pan , Wu Yongming
Published: March 2016

Microcystis occurs as colonies in the natural environment but disaggregates into single cells in laboratory cultures. In order to explore the mechanism of how Microcystis forms colonies, the zeta potentials of Microcystis cells from the laboratory and the field were studied, and the hydrophobicity of Microcystis colonies in different sizes was investigated in Lake Taihu. The incubation experiment indicated that the zeta potentials of Microcystis cells were affected by growth phase and species. The absolute values in exponential phase were lower than those in stationary phase, suggesting that the cells with rapid growth easily formed colonies due to more instability on the cell surface. The values of Microcystis aeruginosa were higher than those of Microcystis flos-aquae, which confirmed that M. aeruginosa prevailed in waters for a longer time and at a larger size compared with M. flos-aquae. In another aspect, the absolute zeta potentials of Microcystis spp. at pH 7.0 decreased from spring to autumn in the field; the values in spring were higher than those in summer, suggesting that a large-sized Microcystis colony would more easily form in summer. Additionally, differences in hydrophobicity exist among Microcystis colonies of various sizes. The surface hydrophobicity of colonies in the <20 μm size class was higher than that of larger colonies. This characteristic allowed small colonies to easily form large colonies to survive better. These results would be helpful to understand the mechanism of the bloom formation, especially the colony formation, in Microcystis.