Publications

One way of generally classifying natural fiber-reinforced plastic (NFRP) composites is according to the type of polymeric resin used as matrix. The thermoplastic-based NFRP composites are presently obtaining a continually expanding range of applications; however, the major portion of the NFRP market is still comprised of biofiber reinforced thermoset-based composites. Thermoset matrix systems dominate the composites industry because they are more reactive and easier to impregnate with fillers. They also play an important role in the industry due to their high flexibility for tailoring desired ultimate properties. Various thermosetting resins have been utilized in the manufacture of composites for their excellent chemical stability, which allows the possibility of long-term applications such as pipes and chemical tank linings. They are also suitable for high temperature applications such as insulators. However, thermosetting resins are brittle at room temperature and have low fracture toughness- hence the necessity for reinforcements such as fibers.

This chapter reviews the recent studies on the manufacture of thermoset biocomposites, which may be produced either by using biothermoset matrices or by using biofiber reinforcements. Because natural fibers, though highly eco-friendly, have poor mechanical strength and low stability, the use of thermosetting matrices offer a distinct advantage when it comes to fabricating NFRP composites designed for very long service lifetime applications.

In this study, the degradation behavior of circulating fluidized bed (CFB) fly ash reinforced unsaturated polyester composites at different loadings of 0%, 10%, 20%, 30%, and 40% CFB fly ash were observed at different temperatures of 30°C, 50°C, and 80°C under acidic environment. The mass uptakes of the samples were recorded at specified time intervals to determine the effects of fly ash content and temperature. Scanning electron microscopy was used to show if there were changes in the microstructure of the samples. Moreover, the glass transition temperature found from the differential scanning calorimetry showed that the types of diffusion behavior that may take place were the Fickian and non-Fickian (Case II). However, the empirical diffusion model used illustrated that only the Fickian diffusion had occurred.

This paper proposes a method for modeling production function of education using a stochastic frontier model with spatial temporal terms. Using a unique dataset that combines school achievement scores with school characteristics from 2005-2008, the efficiency of 4,900 public high schools in the Philippines in converting school inputs into test scores was estimated. Results show that the average inefficiency is at 41% and that there is a significant positive spatial externality in efficiency, which means that efficiency in one school can spill over to its neighbors. The model was found to be robust to various environmental variables included in the estimation. The results of the study will be important to guide policy makers in allocating limited resources to public schools.

Given a multiple time series sharing common autoregressive patterns, we estimate an additive model. The autoregressive component and the individual random effects are estimated by integrating maximum likelihood estimation and best linear unbiased predictions in a backfitting algorithm. The simulation study illustrated that the estimation procedure provides an alternative to the Arellano–Bond generalized method of moments (GMM) estimator of the panel model when T > N and the Arellano–Bond generally diverges. The estimator has high predictive ability. In cases where T ≤ N, the backfitting estimator is at least comparable to Arellano–Bond estimator.

This study examined the different firm-level factors that affect listed Philippine companies’ decision to use derivatives for corporate hedging. Data from annual reports of 74 corporations over a span of five years (2007 to 2011) were gathered, resulting in 329 firm-year observations. Results of random-effects logistic regression showed that, on one hand, firm size and presence of employee stock option plans were significant incentives for firms to use corporate hedging. On the other hand, liquidity and the existence of growth opportunities were negative influences on derivatives usage. These results may be consistent with the reality that the Philippine derivatives market is underdeveloped relative to the rest of Asia. Only large and financially sophisticated firms, such as those that can develop stock option plans, are more likely to utilize corporate hedging techniques. The negative effect of liquidity further supports this assertion. Philippine firms in the sample would rather use liquidity than derivatives as a way of anticipating potential cash flow volatility. Philippine firms may prefer to use financial buffer, rather than financially sophisticated tools such as derivatives. The study exposed that only large or financially savvy corporations are more likely to take advantage of the benefits of hedging. Philippine regulatory agencies and market participants must work harder to make corporate hedging an alternative that all corporations can take advantage of.

This article examines the challenges elderly Filipinos face today. Based on 15 in-depth interviews, I characterize how senior citizens, especially women, aspire to play a productive role in their families in spite of their physical frailties and financial limitations. Contrary to the continuity approach in sociology of aging, this article argues that the elderly wish to redeem their independence— not to pursue an individualized identity but to fulfil obligations to their family. The article also aims to add more nuances to the political economy and dependency accounts of aging by illustrating the different ways the elderly negotiate their roles and aspirations in their current life phase.

Titled Hay, Naku! 2013: Pagsusuma ng Isang Peryodista, the book is authored by Danilo Araña Arao. It is a collection of essays he wrote for Pinoy Weekly in 2013. The articles are divided into 11 chapters on language, propaganda, media, history, elections, law, culture, politics, education, tragedy and mass action. An e-book version is available at http://flipreads.com/hay-naku-2013.

For this paper, the researcher attempts to describe the clause structure of Tagalog using Cognitive Grammar. Abiding by the said framework, sentences are regarded as grammatical constructions that represent different event schemas, which are then categorised into situations in: (1) the material world, or how the structured world exists, changes, or undergoes processes; and (2) the psychological world, or the internal world of human sensation, emotion, perception and thought. Analysing the semantic grammar of Tagalog, that is, looking at linguistic utterances as motivated by the meaning that the speaker wants to express, this study aims to provide new insights with regards to the characteristics of the components of grammar as a reflection of cognition.

Principal components regression (PCR) is used in resolving the multicollinearity problem but specification bias occurs due to the selection only of the important principal components to be included resulting in the deterioration of predictive ability of the model. We propose the PCR in a nonparametric framework to address the multicollinearity problem while minimizing the specification bias that affects predictive ability of the model. The simulation study illustrated that nonparametric PCR addresses the multicollinearity problem while retaining higher predictive ability relative to parametric principal components regression model.

A fossil femur excavated by Euge`ne Dubois between 1891–1900 in the Lower/Middle Pleistocene bonebed of the Trinil site (Java, Indonesia) was recognised by us as that of a Hylobatidae. The specimen, Trinil 5703 of the Dubois Collection (Leiden, The Netherlands), has the same distinctive form of fossilization that is seen in many of the bonebed fossils from Trinil in the collection. Anatomical comparison of Trinil 5703 to a sample of carnivore and primate femora, supported by morphometric analyses, lead to the attribution of the fossil to gibbon. Trinil 5703 therefore provides the oldest insular record of this clade, one of the oldest known Hylobatidae fossils from Southeast Asia. Because living Hylobatidae only inhabit evergreen rain forests, the paleoenvironment within the river drainage in the greater Trinil area evidently included forests of this kind during the Lower/Middle Pleistocene as revealed here.

Although exercise motivation is a well-established research area in exercise and sport psychology in the West, relatively little work on this topic is available in the Philippines. This study explored motives for exercise among Filipinos using an open-ended methodology. Five hundred ninety-two Filipinos aged 15 to 69 were asked to free-list possible motives for exercise participation. Two thousand ninety-five responses (about four per participant) were coded by two independent judges via direct content analysis and using themes derived from the Exercise Motivation Inventory subscales (EMI-2; Markland & Ingledew, 1997). The most frequently identified motives for exercise were highly extrinsic – Filipinos exercise for weight management, positive health, and strength and endurance. Challenge, social recognition, and competition were the least frequently cited motives. Results also surfaced participation motives outside those in the EMI-2, such as exercising to satisfy a requirement, to improve posture, and due to directed social influence from peers and family.