Aileen A. Jara1, Ramon A. Razal1, Veronica P. Migo2, Menandro N. Acda1, Margaret M. Calderon3 and Leonardo M. Florece4
1Department of Forest Products and Paper Science, College of Agriculture and Food Science
2Department of Chemical Engineering, College of Engineering and Agro-Industrial Technology
3Institute of Renewable Natural Resources, College of Agriculture and Food Science
4School of Environmental Science and Management, College of Agriculture and Food Science
UP Los Baños
Chemical Composition of Bambusa vulgaris Shoots as Influenced by Harvesting Time and Height,
Philippine Journal of Crop Science (PJCS), December 2018, 43 (3):1-9
Bambusa vulgaris shoot
Extraction of water soluble extractives from bamboo shoots
Bamboo shoots are available as potential raw materials for various applications. Determining the chemical characteristics of bamboo shoots is vital in assessing their suitability for different treatments. However, research on the chemical properties of bamboo had so far been mostly confined to the mature culms and freshly emerged edible shoots of selected species. Information on height or age groups, such as those of older shoots, is rather limited. Considering the influence of the chemical makeup of a raw material to production processes, the importance of determining the chemical properties of bamboo shoots cannot be overlooked.
To investigate the chemical characteristics of bamboo shoots, Bambusa vulgaris Schrad. Ex Wendl. shoots having heights of 30, 60 and 90 cm were harvested in Los Baños, Laguna, Philippines at the onset and towards the end of the rainy season. Chemical analyses revealed that the shoots consisted of 36.7-49.9% holocellulose, 14.2–29.6% α-cellulose, 11.6 – 20.3% lignin, 5.3-9.2% cyclohexane-ethanol extractives, 24.4-34.9% hot water extractives, and 9.1%-11.6% ash. Shoots harvested at the onset of the rainy season contained more lignin and hot water extractives, and less holocellulose, alpha-cellulose and ash compared to those harvested at the end of the rainy season. Both lignin and ash contents increased with shoot height. The study suggests that harvesting time and shoot height could influence the chemical composition of the shoots; as such, should be taken into consideration for the more efficient utilization of the resource.
Significance:
This study investigated the chemical characteristics of bamboo shoots, in particular, Bambusa vulgaris shoots. Bamboo shoots can serve as potential feedstocks for different bioconversion processes. Chemical characterization of a raw material is vital in determining its suitability for various applications and treatments. However, research on the chemical properties of bamboo had so far been mostly confined to the mature culms and freshly emerged edible shoots of selected species. Information on height or age groups, such as those of older shoots, is rather limited. Considering the influence of the chemical makeup of a raw material to production processes, the importance of determining the chemical properties of bamboo shoots cannot be overlooked. Moreover, since optimizing the harvest time may be one strategy for obtaining more suitable material for subsequent processing, this study focused on the effects of shoot growth, as represented by height, and harvesting time or season, on the chemical properties of the shoots.
Link to the article: https://www.cabdirect.org/cabdirect/abstract/20193038057
Impact factor: (2017/2018) 0.135
Ralph Kristoffer B. Gallegos
Institute of Agricultural Engineering
College of Engineering and Agro-Industrial Technology
UP Los Baños
Small flags in rectangular channels: Dynamics and mean wake characteristics, International Journal of Mechanical Sciences, 155, 518–535. https://doi.org/10.1016/j.ijmecsci.2019.02.033
Oscillation shapes, vortex formation mechanism and wake flow fields of small flags in channels
The paper talks about the behavior of a flapping flag inside a rectangular tube, how it flutters and the characteristics of the flow created around the flag. The motivation for the study came from the potential use of fluttering flags to improve cooling and mixing of air (or any fluid) in thermal and energy systems, like electronics and power systems. For them to work properly, energy and electronic systems need an efficient means of heat transfer or heat dissipation. For heat transfer to be efficient, the air flow around electronic parts should be turbulent and unsteady. This study demonstrated that the use of fluttering flags is an effective way of increasing the turbulence and unsteadiness of the flow, and hence, has great potential for cooling different electronic systems. The study further revealed how the flag interacts with the flow so that vortices are created, which leads to the enhancement of turbulence and flow unsteadiness inside the channel.
Significance:
The paper is a product of the PhD research work of the main author. The study aims to characterize the oscillation dynamics of flexible plates or flags inside rectangular channels. It revealed a mechanism on how vortices were formed inside the channel and the resulting flow field behind the flag. New observations and insights have been extracted from the results, which helped describe the complex behavior of the flag and the flow inside the channel. The results further show that the flag in channel system is effective in increasing the flow unsteadiness and turbulence inside the channel which may be exploited to enhance heat transfer and mixing in thermal and energy systems. Enhanced heat transfer translates to improved heat dissipation or cooling in various applications like electronics and energy systems. Enhanced flow mixing, on the other hand, can be used for effective processing in food and other process industries.
Link to the article: https://www.sciencedirect.com/science/article/pii/S002074031930030X
Impact factor: (2018/2019) 4.134
Ralph Kristoffer B. Gallegos
Institute of Agricultural Engineering,
College of Engineering and Agro-Industrial Technology
UP Los Baños
Heat transfer performance of flag vortex generators in rectangular channels, Int. J. Therm. Sci., vol. 137, pp. 26–44, 2019.
Nusselt number comparison for different channel sizes and flow conditions
Energy and electronic systems need efficient means of heat transfer or heat dissipation for optimum performance. The research focused on the use of small flags as turbulence enhancers to improve the heat transfer inside a rectangular tube. The flag creates vortices as it flaps, thereby enhancing the mixing and turbulence inside the channel, hence the flag is termed vortex generator (VG). The performance of the tube with flag VG is compared to a bare channel, i.e., a channel without flag. The concept has proven to be effective in enhancing heat transfer, increasing the Nusselt number (an indicator of performance) ay as high as 1.62 (62% increase) times bare channel values. However, due to the inclusion of the flag inside the tube, the energy required to drive the flow increased. Thus optimization of parameters is needed to fully exploit the benefits of flag VG.
Significance:
The paper is a product of the PhD research work of the main author. The study aims to characterize the heat transfer enhancement capabilities of flapping flags in rectangular channels. The results show the huge potential of using flags for enhancing heat transfer in thermal and energy systems. The system can be used to improve heat dissipation or cooling in various applications like electronics and energy systems. It can also be used to enhance the mixing of substances flowing inside the channel, which can be beneficial in food and other process industries.
Link to the article: https://www.sciencedirect.com/science/article/pii/S1290072918311013
Impact factor: (2018/2019) 3.488
Binoe E. Abuan
Department of Mechanical Engineering
College of Engineering
UP Diliman
The performance and hydrodynamics in unsteady flow to the performance of horizontal axis tidal turbine, Renewable Energy, Volume 133C, January 2019, Pages 1338-1351, https://doi.org/10.1016/j.renene.2018.09.045
Current designs of horizontal axis tidal turbine in the market are based on steady flow calculations. It means that the fluctuation of the water velocity due to turbulence and other factors are neglected and are assumed to be non-existent to certain levels. The study looks at the effect of water flows that are not steady to the performance output of the HAWT. Comparison with steady flow calculations has been made and results showed that there is a significant decrease in the average performance of HAWT in unsteady flows. Knowing this, designers and engineers can now include this effect of unsteadiness when creating new iterations of current tidal energy extraction devices in the market.
Significance:
The study shows the hydrodynamics of tidal turbines in unsteady flow which is not usually presented because of the complexity of the fluid problem. The results of the study will give new insights and considerations when it comes to design and analysis of horizontal axis tidal turbine performance as this study is the closest we can get to real flow analysis.
Link to the article: https://doi.org/10.1016/j.renene.2018.09.045
Impact Factor: Not yet available
Alexandra B. Santos-Putungan1 and Francis Norman C. Paraan2
1Institute of Mathematical Sciences
College of Arts and Sciences
UP Los Baños
2National Institute of Physics
College of Science
UP Diliman
Strong chemisorption of CO2 on B10–B13 planar-type clusters, J. Phys.: Condens. Matter 31, 145504 (2019)
One of the major problems we are currently facing is the continuous increase of earth’s temperature. One reason for this is the continuous use of fossil fuels that we need to produce energy (electricity). However, among the by-products of burning fossil fuel is carbon dioxide (CO2). CO2 is a greenhouse gas that contributes to global warming. Many researches focus on finding ways to capture and store CO2 from the atmosphere. These include designing and developing complicated structures or materials to capture CO2. In our work, we investigated (using computer simulations) simple Boron structures, which are called Boron clusters, that are comprised of 10-13 atoms, and found that the Boron clusters were able to capture CO2. Also, we calculated that the binding energy is huge such that the CO2 molecule will stick on these Boron clusters. Furthermore, we explained why these sticking of CO2 molecule on Boron clusters could happen by looking on the properties of both the molecule and cluster. Because of this observation, this could pave way and help on designing simple materials that could capture, and minimize, CO2 in the environment.
Significance:
Carbon dioxide (CO2) is a greenhouse gas that contributes to global warming. Various efforts were exerted to develop materials that would capture and sequester CO2 in our atmosphere. In our work, we found a strong adsorption of CO2 molecule on Boron (B) clusters (Bn, n=10-13) using first principles density functional theory. We provide an explanation on how B clusters were able to adsorb CO2, and that the strong adsorption (chemisorption) we found is of great use in designing and fine-tuning future materials for capture and sequestration technology.
Link to the article: https://iopscience.iop.org/article/10.1088/1361-648X/aafebd
Impact factor: (2018/2019) 2.617
Marvin U. Herrera1, Rontgen B. Gapusan2 and Mary Donnabelle L. Balela2
1Institute of Mathematical Sciences and Physics
College of Arts and Sciences
UP Los Baños
2Department of Mining, Metallurgical, and Materials Engineering
College of Engineering
UP Diliman
Removal of methyl orange dye and copper (II) ions from aqueous solution using polyaniline-coated kapok (Ceiba pentandra) fibers, Water Sci Technol (2018) 78 (5): 1137-1147
SEM micrographs of (a,b) kapok fibers and (c,d) polyaniline-coated kapok fibers at 6,000x
Composite of kapok fibers and polyaniline was prepared as an adsorbent that could potentially remove anionic dyes and heavy metals from wastewater. The large surface area of kapok fiber could enhance the efficiency of polyaniline as an adsorbent. The kapoks fibers were extracted from the seed pods of kapok tree. The fibers were washed thoroughly with distilled water and ethanol to remove the unnecessary particulates and substances. Then, the fibers were treated with bleach to remove the waxy layer on its surface, thereby improving the adhesion of the polyaniline. The preparation of kapok and polyaniline composite was initiated by dispersing the kapok fibers in a solution containing hydrochloric acid and aniline (source of polyaniline). A separate solution that contains hydrochloric acid and ammonium persulfate was also prepared. The mixture of kapok fibers, hydrochloric acid and aniline was transferred in an ice bath. The solution of hydrochloric acid and ammonium persulfate was added dropwise to start the formation of polyaniline on the surface of the kapok fiber. The final mixture was left at room temperature for 16 hours. Afterwards, the product was rinsed with distilled water and ethanol, and dried in an oven. Several tests such as electron microscopy and infrared spectroscopy were done on the composite to confirm if the deposition of polyaniline onto the surface of kapok was successful. After the confirmation, the composite were tested for anionic dye and heavy metal removal.
Significance:
Natural tubular cotton-like fiber locally known as kapok was utilized as a template for the deposition of polyaniline for anionic dye and heavy metal removal. Kapok fiber is abundant in our country and it is commonly used as filling in pillows and mattresses. Due to its high surface area-to-volume ratio, thanks to its microtubular structure, we chose it as the substrate for polyaniline. Polyaniline is widely used as an absorbent because of the large amount of nitrogen-based functional groups, that serve as active adsorption sites, present on its polymeric chain. However, application of pure polyaniline is limited due to its low surface area. In addition, product recovery could be a problem because it requires a special filtration process to remove all the adsorbent from the wastewater after adsorption. Deposition of polyaniline on a template such as microtubular fiber could help solve these problems.
Link to the article: https://doi.org/10.2166/wst.2018.385
Impact factor: (2017/2018) 1.247
Clarisson Rizzie P. Canlubo
Institute of Mathematics
College of Science
UP Diliman
Weak Algebra Bundles and Associator Varieties, Philippine Journal of Science, vol. 148 no. 2, 315-322
Vector bundles are important objects associated to geometric objects. They serve as shadows to the geometric structure under consideration. Algebra bundles are vector bundles with an additional structure, one that allows the tools of algebra to be used. Although these bundles are important and appears in many areas in math, their structure is too restrictive. In this research work, we weaken the structure of an algebra bundle to come up with what we call a weak algebra bundle. We showed in the article that they are more natural than their strict counterpart. In particular, we pointed out one particular weak algebra bundle, called the classifying weak algebra bundle, that for a particular dimension controls the other weak algebra bundle of the same dimension. Lastly, we gave a necessary and sufficient condition when a weak algebra bundle is a strict algebra bundle. In other words, we gave a way to determine whether the weak structure at hand is among the classically studied ones.
Significance:
The research under consideration defines a weak algebra bundle, called the classifying weak algebra bundle, that plays the role the Grassmanian spaces play for ptincipal O(n)-bundles.
Link to the article: http://philjournalsci.dost.gov.ph/next-issue
Impact factor: Not yet available
Deborah N. Tangunan and Alyssa M. Peleo-Alampay
National Institute of Geological Sciences
College of Science
UP Diliman
Late Pleistocene to Holocene productivity changes in the western equatorial Pacific (Sulu Sea, Philippines) from calcareous nannofossils. Marine Micropaleontology,143, 1-11. doi:10.1016/j.marmicro.2018.07.001
Multicore samples collected from Sulu Sea during the PhilEx research expedition onboard RV Melville. The fossils in this study were extracted from these sediments.
Photomicrographs of calcareous nannofossils from Sulu Sea. Scale bar= 2 microns. (A) Calcidiscus leptoporus; (B) Ceratolithus cristatus; (C) Emiliania huxleyi; (D) Florisphaera profunda; (E) Gephyrocapsa oeanica; (F) G. ericsonii; (G) Helicosphaera carteri; (H) Neosphaera coccolithomorpha; (I) Reticulofenestra minuta; (J) Umbellosphaera irregularis; (K) Umbilicosphaera sibogae; (L) U. tenuis.
Calcareous nannofossils called coccolithophores reflect past oceanographic conditions due to their high sensitivity to environmental factors. In this study, coccolithophores were used as proxies to reconstruct past productivity and oceanographic conditions in the Sulu Sea. Two sediment cores from the Sulu Sea were subjected to coccolithophore and sediment geochemistry analyses. One core was located in the high productivity, upwelling area off Zamboanga Peninsula while the other core was situated at a non-upwelling area off Panay Island. Results showed that high productivity indicator species were more abundant in the core obtained off Zamboanga Peninsula. On the other hand, low productivity indicator species were more abundant in the core from off Panay Island. Several upwelling events were recorded off Zamboanga Peninsula. This high productivity area probably started as early as 2500 B.P. while the low productivity area off Panay Island possibly initiated around 4000 years B.P.
Significance:
The Sulu Sea is a deep water basin bordered by the Palawan in the northwest, Panay and Negros in the northeast, Zamboanga in the southeast, and Sabah in the southwest. The basin is regarded as one of the major fishing grounds of the Philippines. The study aims to obtain knowledge on the short and long term productivity trends in the Sulu Sea. This information may be used in improving management of fish and other marine resources in the area.
Link to the article: https://www.sciencedirect.com/science/article/pii/S0377839816301219
Impact factor: (2017/2018) 1.874
Kloudene A. Salazar, Allan Christopher C. Yago and Roland V. Sarmago
National Institute of Physics
College of Science
UP Diliman
Combination of post-growth treatments and their effects on ZnO microrods as potential UV Phosphors, Optical Materials 86, 12-17 (2018)
SEM images of the ZnO microrods with different post-growth treatments.
TIPL spectra of the ZnO microrods with different post-growth treatments
The continued interest on Zinc Oxide (ZnO) is fueled by its potential as a base material for the production of various optoelectronic devices such as UV photodetectors, lasers, gas sensors, and other light-activated smart materials. Research efforts are then aimed at modifying ZnO properties not only through material growth but also through post – growth treatment to capitalize on the versatility and functionability of the ZnO semiconductor. This study aims to investigate and compare the effects of PVP coating, annealing and PVP coating with subsequent annealing on the properties of hydrothermal-grown micorods, and to provide an insight to the potential application of ZnO microrods. Results show that the post-growth treatments through PVP coating and thermal annealing offer a way to reduce the defect related visible emission and improves the relative UV emission efficiency without degrading the crystallinity of the ZnO microrods. Coupled with with intense picosecond UV emission, improved UV emission efficiency, and stable crystal structure, the ZnO microrods could be developed as fast UV phosphors which when embedded into a suitable polymer matrix can offer a wider range of optoelectronic applications as functional composite materials.
Significance:
The continued interest on Zinc Oxide (ZnO) is fueled by its potential as a base material for the production of various optoelectronic devices such as UV photodetectors, lasers, gas sensors, and other light-activated smart materials. However, a common problem for ZnO is the presence of both shallow, and deep donor and acceptor defect states. These defect states are often addressed by using a different fabrication method. In an attempt to address this problem, and to develop the functionality and versatility of ZnO semiconductor, research efforts are then aimed at modifying ZnO properties not only through material growth but also through post – growth treatment.
This research to investigate the effects of PVP coating, annealing, and PVP coating with subsequent annealing on the properties of the hydrothermal-grown microrods, and to provide an insight to the potential application of ZnO microrods.
Link to the article: https://doi.org/10.1016/j.optmat.2018.09.018
Impact factor: (2017/2018) 2.687
