Research

As the national university, we champion and support innovative research that addresses the country’s most pressing challenges.

28 Feb 2025

UP Diliman

Transforming higher education requires a more diverse and inclusive landscape especially for women and minority groups in STEAM

This research dives into how higher education can be transformed through leadership focused on Equity, Diversity, and Inclusion (EDI). In...

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26 Feb 2025

UP Diliman

The proposed Input-Process-Output-Outcome/Result Model evaluates the success of the Philippine Olympic Committee Athletes’ Commission

The paper discusses the various institutions, laws, policies and programs of Olympic governance in the Philippines from the American era...

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25 Feb 2025

UP Diliman

Approximately 30% of older adults worldwide suffer from falls each year, making falls a critical public health issue

This study utilized baseline survey data from the Longitudinal Study of Ageing and Health in the Philippines (LSAHP) and the...

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18 Feb 2025

UP Diliman

Preventing frailty and depression may improve sleep health in those who are food insecure

Extensive research reveals the close relationship between food insecurity and the occurrence of sleep problems due to mental health. In...

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17 Feb 2025

UP Los Baños

Verb-controlled that-clauses are the most useful finite complement clauses in applied linguistics, communication, and measurement and evaluation research articles

The study cross-investigated finite complement clauses (FCCs) in qualitative (QUALI) and quantitative (QUANTI) research articles (RAs) written by Filipino academic...

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12 Feb 2025

UP Los Baños

Machine learning can identify cancerous samples with almost 100% accuracy and could thus replace the current, more traumatic screening methods

The success rate of treating colorectal cancer (CRC) can be greatly increased through the early and accurate diagnosis of the...

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11 Feb 2025

UP Diliman

Roger Felix Salditos’s writings offer a key perspective on the persistence of one of the world’s longest-running rural insurgencies

Roger Felix V. Salditos was among seven Filipino revolutionaries who were summarily executed by police and military forces in San...

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11 Feb 2025

UP Visayas

Boracay, Gigantes and Guimaras islands are in potentially sustainable status according to locals and visitors

This study considered the interaction or nexus of people and the natural resources in small island tourist destinations in the...

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10 Feb 2025

UP Diliman

Can we use acoustic indices to estimate the relative number of bird species in urban areas?

Birds are used as biological indicators of ecosystem health. They are often surveyed through point count method which requires skilled...

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10 Feb 2025

UP Diliman

Mindset and emotional resilience, known as psychological capital, can improve the overall educational experience of students and teachers

This paper delves into how the mindset and emotional resilience—referred to as psychological capital or PsyCap—of students and teachers in...

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07 Feb 2025

UP Manila

The use of skin-lightening products is linked to psychological distress among Filipinos

The Philippines is one of Southeast Asia’s top consumers of beauty products. There have been few studies on the psychological...

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06 Feb 2025

UP Los Baños

Two species belonging to the group of species commonly known as lagundi were found to be endemic to the Philippines

The Vitex trifolia complex in the Philippines consists of economically important medicinal species, including five species collectively referred to as medicinal “lagundi”. The V. trifolia complex...

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Research

The behavior of granular materials subjected to shaking or vibration remains a complex puzzling phenomenon. A reliable strategy in science to deal with such challenges is to use toy models as a starting point for a more complete and nuanced understanding. A toy model is an idealized version of the real thing reduced to its essential features. (The determination of what is essential is not simple and depends on one’s interest and purpose.)

The inelastic bouncing ball model (IBBM) was identified as a toy model for shaken granular materials. The IBBM treats the bulk of granular materials as a single inelastic ball on a harmonically vibrating container. The ball plate detaches from the container once its acceleration exceeds gravity and loses all its kinetic energy whenever it collides with the container.

The next step towards understanding is to analyze the discrepancies between the toy model and the real thing. More than a decade ago, it was observed that the time-of-flight of the shaken granular materials is less than what is predicted by IBBM. The researchers back then suspected that this discrepancy was due to the failure to consider the duration of the collision. However, this line of thought was not fully pursued until recently.

Recently, the team of researchers from the University of the Philippines consisting of Junius Andre F. Balista of UP Los Banos and Christian Jay P. Magsigay and Caesar Saloma of UP Diliman revisited the problem. Using numerical simulation (discrete element method) and analytical modeling, they analyzed the collision between the granular material and the container. They proposed a modification to IBBM by considering the collision time between the ball and its container as the range of uncertainty of the lift-off time of the ball.

There is more to be done but this is the first successful effort to include collision time in the formulation of IBBM, not to mention that not much has been accomplished on the issue in more than a decade. The modification of IBBM makes it applicable to other granular material phenomena driven by the material properties of the grains, such as the mixing and segregation of granular mixtures.

Authors: Junius Andre F. Balista (Institute of Mathematical Sciences and Physics, University of the Philippines Los Baños), Christian Jay P. Magsaysay (National Institute of Physics, University of the Philippines Diliman) and Caesar A. Saloma (National Institute of Physics, University of the Philippines Diliman)

Read the full paper: https://link.springer.com/article/10.1007/s10035-024-01403-9