Research

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

12 Sep 2024

UP Mindanao

Tarsiers need small forest fragments to survive, making it crucial to protect these isolated environments

The Philippine tarsier Carlito syrichta (Linnaeus, 1758) is considered a specially protected flagship species in the Philippines. However, the species is threatened...

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20 Aug 2024

UP Mindanao

In Visayan and Mindanao epics, the “Man With No Breath” is seen as deathless and invulnerable, contrary to the common view of continuous breathing as a sign of wellbeing

In Visayan and Mindanao epics, one encounters the figure of an enigmatic character called the “Man With No Breath”. This...

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09 Aug 2024

UP Diliman

Height and height differences impact different areas of life including jobs, education, sports and social interactions

This review article examines the meanings and materialities of human stature, from serving as a marker of human difference to...

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02 Aug 2024

UP Los Baños

Saba banana peels offer many health benefits including potential effectiveness in treating obesity and related disorders

This study presents a comprehensive investigation into the potential health benefits of saba banana peel (SBP). The study reveals that...

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29 Jul 2024

UP Manila

Pharmacy students are skilled in nonverbal communication and language use, but less confident in developing and managing treatment plans

Pharmacists are in a unique position to provide important medication information, prevent errors, and help improve patient outcomes. Patient medication...

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19 Jul 2024

UP Los Baños

Large-scale study involving samples from 90 countries reveals that butterflies originated approximately 100 million years ago in what is now the Americas

The research, conducted over seven years and involving over 80 scientists worldwide, aims to contribute to our understanding of butterfly...

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16 Jul 2024

UP Diliman

The dozens of animal engravings discovered in the Atxurra cave in Basque Country, Spain prove that there is planning before artistic production during the Upper Palaeolithic

The Atxurra cave (Basque Country, Spain) is an exceptional place to learn about the Magdalenian artists in Europe. A unique...

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26 Jun 2024

UP Diliman

Traditional Thai music was combined with Western classical music to develop unique chamber music pieces that more people can appreciate

Imagine blending the intricate melodies of Thai traditional music with the rich harmonies of Western classical music to create something...

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18 Jun 2024

UP Diliman

The Vocabulario de Iapon (Japanese Vocabulary) is both typical and unique among books first printed in the Philippines from 1593 to 1640

Books go through a process of transformation from uniformity to uniqueness in the course of their survival. Some of these...

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13 Jun 2024

UP Diliman

The lack of a consistent Southeast Asian values system may explain the ongoing sexual prejudice toward lesbian women and gay men in the region

Homonegativity or negative attitudes towards lesbian women and gay men still persist in Southeast Asian countries. Such attitudes not only...

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11 Jun 2024

UP Diliman

Research investigates how crowdsourcing, digital co-production and collaborative governance can modernize local public transport services

The SafeTravelPH Public Transport Crowdsourcing App, which was designed as part of a bigger research, is a platform that actively...

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04 Jun 2024

UP Diliman

Intrinsic goal orientation or motivation varies among students from different cultural backgrounds

This study investigates the motivation of university students in Indonesia, Thailand, Bangladesh, and China for online learning. It analyzes how...

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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