Cherry Ringor

University of the Philippines Diliman, College of Science - Institute of Environmental Science & Meteorology, Faculty Member

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Andrej Dujella

University of Zagreb

Hemin Koyi

Uppsala University

Jana Javornik

University of East London

Armando Marques-Guedes

UNL - New University of Lisbon

Graham Martin

University of Leicester

Gwen Robbins Schug

University of North Carolina at Greensboro

Gabriel Gutierrez-Alonso

University of Salamanca

John Sutton

Macquarie University

Eros Carvalho

Universidade Federal do Rio Grande do Sul

Kevin Arbuckle

Swansea University

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Papers by Cherry Ringor

High Yield Preparation of Fullerene Nanowhiskers and Nanotubes by the Solution Route

Nano, 2008

The effect of ultraviolet, visible and near-infrared irradiation on the yield and morphology of s... more The effect of ultraviolet, visible and near-infrared irradiation on the yield and morphology of single crystalline C 60 fullerene nanowhiskers (FNWs) and nanotubes (FNTs) was investigated in an effort to produce large-scale quantities of FNWs and FNTs. These fullerene nanomaterials were synthesized by the liquid–liquid interfacial precipitation method using pyridine and isopropyl alcohol (IPA) as solvents. The C 60–pyridine solution was illuminated using different wavelengths for 24 h at ambient pressure and temperature before addition of IPA. High yields (30–38 mg/L) were obtained upon irradiation using wavelengths in the ultraviolet region in accordance with the increased photoabsorption signal of solid C 60 and C 60 dissolved in pyridine acquired by a UV-VIS-NIR spectrophotometer. However, elevated yields (21–27 mg/L) were also obtained in the 600–800 nm regions, where C 60 absorption is particularly weak. Such an enhanced yield of FNTs and FNWs is probably related to the reported rise in transient absorption of the triplet excited state of C 60 in the 740 nm region formed by the decay of the photoexcited singlet C 60 through intersystem crossing. The formation of photopolymerized fullerene nanofibers was also observed by Raman spectroscopy, it is attributed to ultraviolet and visible light irradiation. SEM and TEM observations suggest that preparation of FNWs and FNTs by irradiation using different wavelengths of light does not produce apparent morphological transformations on the surface of these fullerene materials.

Synthesis of Fullerene Nanotubes and Microtubes for Materials Storage, Delivery and Recovery

Nano, 2008

Tubular, needle-like crystals of C 60 with diameters ranging from micro to nano sizes have been s... more Tubular, needle-like crystals of C 60 with diameters ranging from micro to nano sizes have been synthesized by the liquid–liquid interfacial precipitation (LLIP) method. The C 60 nano- and microtubes can absorb various solutions of alcohol and water, showing that they can be promising containers for materials storage and recovery. Further, C 60 microtubes vertically aligned on porous alumina membranes have been successfully prepared for the first time by a modified LLIP method. The vertically aligned C 60 microtubes will find a variety of application for bio and environmental uses.

Synthesis of C-60 fullerene nanotubes by the liquid-liquid interfacial precipitation method

Last interglacial (marine isotope stage 5) sea level and climate changes in southwest Bohol, central Philippines

ABSTRACT

Enhanced Growth of C60 Nanotubes by Illumination with UV Light

Synthesis of C-60 fullerene nanotubes by the liquid-liquid interfacial precipitation method

Synthesis of Fullerene Nanotubes and Microtubes for Materials Storage, Delivery and Recovery

Nano, 2008

Last Interglacial Sea Level Changes Deduced from Coral Reef Terraces in Southwest Bohol, Central Philippines

The Quaternary Research (Daiyonki-Kenkyu), 2004

Structural Analysis of C60 Nanotubes Heat-Treated in Vacuum

IEEJ Transactions on Sensors and Micromachines, 2008

The structural change of C60 nanotubes (C60NTs) by heating in vacuum was investigated using therm... more The structural change of C60 nanotubes (C60NTs) by heating in vacuum was investigated using thermo-gravimetric analysis (TGA), transmission electron microscopy (TEM) and Raman spectroscopy. The C60NTs were prepared by use of a pyridine solution saturated with C60 and isopropyl alcohol (IPA). A weight loss of about 4 % in the C60NTs dried at room temperature was observed by heating up

High Yield Preparation of Fullerene Nanowhiskers and Nanotubes by the Solution Route

Nano, 2008

Covered conduction of individual C 60 nanowhiskers

Nanotechnology, 2008

We investigate the electronic properties of individual C(60) nanowhiskers by exploiting conductiv... more We investigate the electronic properties of individual C(60) nanowhiskers by exploiting conductive atomic force microscopy at room temperature in ambient atmosphere. The pristine individual C(60) nanowhiskers exhibit conducting behavior. The outer C(60) oxide covering, confirmed by Auger electron spectroscopy, shelters the conductive properties of the C(60) nanowhiskers. It is proposed that the insulating outer C(60) oxide covering might be used as the dielectric layer in potential single C(60) nanowhisker-based field-effect transistors for nanoelectronics.

Platinum chloride deposition into C60 nanotubes

Materials Letters, 2008

Deposition of platinum chloride (PtCl 4 ) into C 60 nanotubes (C 60 NTs) was investigated using t... more Deposition of platinum chloride (PtCl 4 ) into C 60 nanotubes (C 60 NTs) was investigated using transmission electron microscopy (TEM). The asprepared C 60 NTs showed a Raman profile indicating the formation of one-dimensionally polymerized structure of C 60 molecules and C 60 dimers. However, the C 60 NTs dried at room temperature turned to van der Waals polymers. The deposition of PtCl 4 was successfully performed by infiltrating an isopropyl alcohol (IPA) solution of PtCl 4 into the C 60 NTs dried in vacuum. It is suggested that the C 60 NTs can be used as carriers for various chemical substances, including the use to recover Pt from liquid wastes.

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Molecular dynamics and structural phase transition in C 60 nanowhiskers

Journal of Physics: Conference Series, 2009

ABSTRACT Nanowhiskers of C60 (C60 NWs) have been formed by a liquid-liquid interfacial precipitat... more ABSTRACT Nanowhiskers of C60 (C60 NWs) have been formed by a liquid-liquid interfacial precipitation method which uses an interface of the concentrated toluene solution of C60/2-propanol. In order to study the motion of C60 molecules in nanowhiskers, we have performed measurements of low-temperature X-ray diffraction, magnetic susceptibility, specific heat and 13C-NMR for C60 NWs. The temperature dependence of lattice constant for C60 NWs is in good agreement with that for pristine C60 powder, which demonstrates the large discontinuity at Tc ~ 265 K caused by the structural phase transition. However, the temperature dependence of magnetic susceptibility for C60 NWs exhibits a faint anomaly at Tc. The temperature dependence of specific heat for C60 NWs shows two small anomalies at 232 K and 254 K. High resolution 13C-NMR measurements of the C60 NWs indicate that both of toluene and 2-propanol molecules interact with the C60 NW molecules in the suspension and the precipitate states obtained from the LLIP method. The broader linewidth of 13C-NMR in the dried C60 NWs compared with that in the pristine C60 powder indicates that the slower molecular reorientation in the dried C60 NWs compared with that in the pristine C60 powder. Since a rapid rotation of C60 molecules could be directly detected by 13C-NMR, polymer formation between C60 molecules is unlikely in C60 NWs at room temperature.

Fabrication of Solution Grown C<SUB>60</SUB> Fullerene Nanotubes with Tunable Diameter

Journal of Nanoscience and Nanotechnology, 2009

Synthesis of C60 nanotubes by liquid–liquid interfacial precipitation method: Influence of solvent ratio, growth temperature, and light illumination

Diamond and Related Materials, 2008

ABSTRACT Nanotubes composed of C 60 fullerene molecules (C 60 NTs) were synthesized at ambient pr... more ABSTRACT Nanotubes composed of C 60 fullerene molecules (C 60 NTs) were synthesized at ambient pressure and temperature using a modified liquid– liquid interfacial precipitation (LLIP) method in the system of C 60 –pyridine and isopropyl alcohol (IPA). A marked improvement in the formation of C 60 NTs was achieved by illuminating the initial C 60 –pyridine solution with visible light (VIS, 436 nm) and ultraviolet light (UV, 302 nm). It was also found that the growth and diameter of C 60 NTs are influenced by the combined effect of solvent ratio and incubation temperature. We present a simple approach of fabricating C 60 NTs designed to optimize rapid growth and to control diameter distributions useful for further discoveries of their chemical and physical properties and in the advancement of their possible applications in nanotechnology. The collected C 60 NTs were characterized by a variety of analytical techniques including scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), and Raman spectroscopy.

EVALUATION OF THE SPATIAL DISTRIBUTION OF EVACUATION CENTERS IN METRO MANILA, PHILIPPINES

by Edward P Cajucom, George Chao, and Cherry Ringor

The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XLII-3/W8, 2019 Gi4DM 2019 – GeoInformation for Disaster Management, 3–6 September 2019, Prague, Czech Republic, 2019

In a densely populated and hazard-prone megalopolis like Metro Manila, the ability to execute a r... more In a densely populated and hazard-prone megalopolis like Metro Manila, the ability to execute a rapid evacuation protocol is crucial in saving lives and minimizing the damage during disastrous events. However, there is no centralized database on the location of evacuation centers (ECs) in Metro Manila and the available lists are not up-to-date. This study geotagged the current list of ECs in Metro Manila obtained from different government agencies to evaluate the spatial distribution using Geographical Information System (GIS). This is important since the immediate evacuation of residents depends on the proximity and safe location of the ECs. A total of 870 ECs were geo-tagged and validated using the street view of Google Earth TM. EC-to-population ratios were calculated for each of the 16 cities and one municipality of Metro Manila. Values range from ~3,000 to 81,000 persons per EC. Distance analysis using Thiessen Polygon shows that the ECs are not evenly distributed with proximity areas ranging from 0.0009 to 9.5 km 2. Out of the total number of mapped ECs, 392 (45%) are situated in flood-prone areas while 108 (12%) are within the 1-km buffer hazard zone of an active faultline. Re-evaluation of the locations and the number of ECs per city or municipality is highly recommended to facilitate prompt evacuation when disasters strike.

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Fullerenes, Nanotubes and Carbon Nanostructures Pleated Surface Morphology of C 60 Fullerene Nanowhiskers Incorporated by Polyaniline in N- Methyl-2-Pyrrolidone

by Cherry Ringor, Katherine Calamba, and Chelo Pascua

The addition of polyaniline emeraldine base dissolved in N-methyl-2-pyrrolidone (PAni/NMP) on ful... more The addition of polyaniline emeraldine base dissolved in N-methyl-2-pyrrolidone (PAni/NMP) on fullerene C 60 whiskers (FW) by direct-mixing technique resulted to the formation of a hybrid material herein called FW/PAni hybrid. The FW/PAni hybrid has a tubular structure with pleated surface texture. It is thinly coated with PAni and has a higher surface area relative to pristine FW and PAni. Beneath the amorphous outer covering, the hybrid shows a crystalline structure as shown by high resolution TEM and selected area electron diffraction. Charge transfer (CT) interaction from electron-rich PAni to electron deficient FW may have resulted to the physical chain entanglement of PAni to FW. The tubular structure of the hybrid is likely caused by the lone pair electrons present in both NMP and PAni causing dissolution inside the whisker. The FW/PAni hybrid having a large surface area and narrow pore size distribution has potential use as hydrogen adsorbent for fuel cell applications, catalysts, and templates for nanofabrication.

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Multiwalled Carbon Nanofibers and Nanocapsules Synthesized from Plant Oil via Atmospheric CVD Process

by Cherry Ringor and Ian Jasper Agulo

Calophyllum inophyllum (CI) oil was used as precursor source material in carbon nanomaterial synt... more Calophyllum inophyllum (CI) oil was used as precursor source material in carbon nanomaterial synthesis. CI is a non-edible and native plant species in the Philippines, which makes production of seeds and kernel sustainable. An atmospheric pressure chemical vapor deposition system was designed and built for the synthesis. Different carbon-based nanostructures were synthesized by varying the Argon gas flow rates (3.5–5 liter/min) and temperatures (1000–1200 C). Crystalline multiwalled nanofibers and iron carbide-encapsulated nanocapsules were formed at 1000 C and a gas flow rate of 5 liter/min. On the other hand, oils synthesized at 1100–1200 C produced amorphous film-like carbon materials. The different morphologies reflect the influence of the gas flow rate on the dilution and atomization of the oil and its decomposition at various temperatures used. Raman spectroscopy and surface potential measurements indicate the potential applications of these nanofibers for hydrogen storage and semiconducting devices.

$Figure 6. AFM images (5.00 x 5.00 um) showing the surface morphol- ogy (a) and the surface potential (b) of multiwalled nanofibers synthe- sized at 1000 °C and Ar gas flow rate of 5 liter/min. The average potential difference is 370 mV. Figure 5. HRTEM images of carbon nanomaterials synthesized at 1100 °C and 5 liter/min gas flow rate. (a) Low-magnification image. (b) Magnified image of a single fiber exhibits the amorphous nature of the material. The XRD profiles shown in Figures 8(a and b) resem- ble the Pseudo-Voight function. The data show that as the experimental temperature increases, the diffraction inten- sities decrease indicating the formation of crystalline and amorphous nanomaterials at lower and higher tempera- tures, respectively (Figs. 8(a—c)). At 1000 °C, the promi- nent peaks were assigned as 002, 100, 101, 102, and 004 peaks of 2H-graphite phase (Fig. 8(a)). The most$

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Net Sediment Transport in Pampanga Bay, Northwestern Manila Bay Derived from Grain Size Trends, Bathymetric Change and Landsat Data

Pampanga Bay receives 50% of the total annual freshwater budget of Manila Bay and has the largest... more Pampanga Bay receives 50% of the total annual freshwater budget of Manila Bay and has the largest river sediment input. The supply of high loads of sediments has significant implications on the aquatic productivity, coastal evolution and contaminant dispersal in the bay. Sediment dispersal patterns were determined using Landsat Thematic Mapper (TM) imageries, trends of grain size parameters, and water depth changes. Satellite data showed a west-southwest and southward alongshore transport of suspended sediments. Transport of bottom sediments is defined by the analysis of grain size trends, showing seaward trending vectors in shallow waters (~5 m depths) and landward trending vectors in deeper waters, which indicate that sediments deposited in the offshore region are further reworked predominantly northward toward the middle part of the bay. This transport pattern is further supported by bathymetric changes over a period of 13 yr. The central region of the bay shows net shoaling while deepening is dominant nearshore. Results of this study generally agree with reported numerical circulation models of the bay except near the mouth of the Pampanga River. The differences can be attributed to high rates of subsidence, which were not considered in the models. This study shows that combination of the different methods yields a better understanding of coastal sediment transport since net and seasonal variations in transport pathways can be established as well as the potential of deposited sediments for reworking. Satellite images provide a significant advantage in that they reveal instantaneous lateral distribution and transport of surface sediments, while analyses of grain size trends and bathymetric changes present information on the long-term fate of the sediments after they are deposited over a longer time scale. This multiple approach is particularly useful in the prediction of areas vulnerable to contamination within the bay.

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High Yield Preparation of Fullerene Nanowhiskers and Nanotubes by the Solution Route

Nano, 2008

Synthesis of Fullerene Nanotubes and Microtubes for Materials Storage, Delivery and Recovery

Nano, 2008

Synthesis of C-60 fullerene nanotubes by the liquid-liquid interfacial precipitation method

Last interglacial (marine isotope stage 5) sea level and climate changes in southwest Bohol, central Philippines

ABSTRACT

Enhanced Growth of C60 Nanotubes by Illumination with UV Light

Synthesis of C-60 fullerene nanotubes by the liquid-liquid interfacial precipitation method

Synthesis of Fullerene Nanotubes and Microtubes for Materials Storage, Delivery and Recovery

Nano, 2008

Last Interglacial Sea Level Changes Deduced from Coral Reef Terraces in Southwest Bohol, Central Philippines

The Quaternary Research (Daiyonki-Kenkyu), 2004

Structural Analysis of C60 Nanotubes Heat-Treated in Vacuum

IEEJ Transactions on Sensors and Micromachines, 2008

High Yield Preparation of Fullerene Nanowhiskers and Nanotubes by the Solution Route

Nano, 2008

Covered conduction of individual C 60 nanowhiskers

Nanotechnology, 2008

Platinum chloride deposition into C60 nanotubes

Materials Letters, 2008

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Molecular dynamics and structural phase transition in C 60 nanowhiskers

Journal of Physics: Conference Series, 2009

Fabrication of Solution Grown C<SUB>60</SUB> Fullerene Nanotubes with Tunable Diameter

Journal of Nanoscience and Nanotechnology, 2009

Synthesis of C60 nanotubes by liquid–liquid interfacial precipitation method: Influence of solvent ratio, growth temperature, and light illumination

Diamond and Related Materials, 2008

EVALUATION OF THE SPATIAL DISTRIBUTION OF EVACUATION CENTERS IN METRO MANILA, PHILIPPINES

by Edward P Cajucom, George Chao, and Cherry Ringor

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Fullerenes, Nanotubes and Carbon Nanostructures Pleated Surface Morphology of C 60 Fullerene Nanowhiskers Incorporated by Polyaniline in N- Methyl-2-Pyrrolidone

by Cherry Ringor, Katherine Calamba, and Chelo Pascua

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Multiwalled Carbon Nanofibers and Nanocapsules Synthesized from Plant Oil via Atmospheric CVD Process

by Cherry Ringor and Ian Jasper Agulo

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Net Sediment Transport in Pampanga Bay, Northwestern Manila Bay Derived from Grain Size Trends, Bathymetric Change and Landsat Data

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