https://mjst.ustp.edu.ph/index.php/mjst/issue/feed Mindanao Journal of Science and Technology 2020-06-05T00:32:03+00:00 Ruel R. Cabahug, Ph.D. mjst@ustp.edu.ph Open Journal Systems <div id="panel-7268-2-0-0" class="so-panel widget widget_heading panel-first-child" data-index="3"> <div class="thim-widget-heading thim-widget-heading-base"> <div class="sc_heading text-center"><center><strong>EDITORIAL BOARD</strong><center></center></center></div> </div> </div> <div id="panel-7268-2-0-1" class="so-panel widget widget_sow-editor panel-last-child" data-index="4"> <div class="so-widget-sow-editor so-widget-sow-editor-base"> <div class="siteorigin-widget-tinymce textwidget"> <table> <tbody> <tr> <td><img src="/public/site/images/mjst_admin/Cabahug.jpg" width="130" height="130"><br><strong>Editor-in-Chief</strong><br><strong>Ruel R. Cabahug, Ph.D.</strong><br>University of Science and Technology of Southern Philippines<br>Philippines</td> </tr> </tbody> </table> <table> <tbody> <tr> <td><img src="http://cdo.ustp.edu.ph/wp-content/uploads/2017/11/Maglaya.jpg" alt="" width="130" height="130"><br><strong>Archie B. Maglaya, Dr. Tech.</strong><br>De La Salle University<br>Philippines</td> <td><img src="http://cdo.ustp.edu.ph/wp-content/uploads/2017/11/Chambers.jpg" alt="" width="130" height="130"><br><strong>Therese Chambers, Ph.D.</strong><br>University of Technology<br>Jamaica</td> </tr> <tr> <td><img src="http://cdo.ustp.edu.ph/wp-content/uploads/2017/11/Yassin.jpg" alt="" width="130" height="130"><br><strong>Mohamed Fathy Yassin, Ph.D.</strong><br>Kuwait University<br>Kuwait</td> <td><img src="http://cdo.ustp.edu.ph/wp-content/uploads/2017/11/Oloke.jpg" alt="" width="130" height="130"><br><strong>David A. Oloke, Ph.D.</strong><br>University of Wolverhampton<br>United Kingdom</td> </tr> <tr> <td><img src="http://cdo.ustp.edu.ph/wp-content/uploads/2017/11/Metillo.jpg" alt="" width="130" height="130"><br><strong>Ephrime B. Metillo, Ph.D.</strong><br>Mindanao State University - Iligan Institute of Technology<br>Philippines</td> <td> <p><img src="http://cdo.ustp.edu.ph/wp-content/uploads/2017/11/Reyes.jpg" alt="" width="130" height="130"><br><strong>Rosula SJ Reyes, Ph.D.</strong><br>Ateneo de Manila University<br>Philippines</p> </td> </tr> <tr> <td><img src="http://cdo.ustp.edu.ph/wp-content/uploads/2017/11/Edwards.jpg" alt="" width="130" height="130"><br><strong>David J. Edwards, Ph.D.</strong><br>Birmingham City University<br>United Kingdom</td> <td><img src="http://cdo.ustp.edu.ph/wp-content/uploads/2017/11/Hjorth.jpg" alt="" width="130" height="130"><br><strong>Peder Hjorth, Ph.D.</strong><br>Lund Institute of Technology-Lund University<br>Lund, Sweden</td> </tr> <tr> <td><img src="http://cdo.ustp.edu.ph/wp-content/uploads/2017/11/Mgaya.jpg" alt="" width="130" height="130"><br><strong>Yunus D. Mgaya, Ph.D.</strong><br>University of Dar es Salaam<br>Tanzania</td> <td><img src="http://cdo.ustp.edu.ph/wp-content/uploads/2017/11/Murad.jpg" alt="" width="130" height="130"><br><strong>Masrah Azrifah Azmi Murad, Ph.D.</strong><br>University of Putra Malaysia<br>Malaysia</td> </tr> <tr> <td><img src="http://cdo.ustp.edu.ph/wp-content/uploads/2017/11/Albina.jpg" alt="" width="130" height="130"><br><strong>Dionel O. Albina, Ph.D.</strong><br>University of Science and Technology of Southern Philippines<br>Philippines</td> <td><img src="/public/site/images/mjst_admin/Dr._Canencia_2.jpg" width="130" height="130"><br><strong>Oliva P. Canencia, Ph.D.</strong><br>University of Science and Technology of Southern Philippines<br>Philippines</td> </tr> <tr> <td><img src="http://cdo.ustp.edu.ph/wp-content/uploads/2017/11/Robson.jpg" alt="" width="130" height="130"><br><strong>Mark G. Robson, Ph.D.</strong><br>The State University of New Jersey<br>United States of America</td> <td><img src="http://cdo.ustp.edu.ph/wp-content/uploads/2017/11/Bergado.jpg" alt="" width="130" height="130"><br><strong>Dennes T. Bergado, Ph.D.</strong><br>Asian Institute of Technology<br>Thailand</td> </tr> <tr> <td><img src="http://cdo.ustp.edu.ph/wp-content/uploads/2017/11/Cultura.jpg" alt="" width="130" height="130"><br><strong>Ambrosio B. Cultura, II, Ph.D.</strong><br>University of Science and Technology of Southern Philippines<br>Philippines</td> <td><img src="http://cdo.ustp.edu.ph/wp-content/uploads/2017/11/Parn.jpg" alt="" width="130" height="130"><br><strong>Erika Pärn</strong><br>Birmingham City University<br>United Kingdom</td> </tr> <tr> <td><img src="http://cdo.ustp.edu.ph/wp-content/uploads/2017/11/Khatib.jpg" alt="" width="130" height="130"><br><strong>Jamal Khatib, Ph.D.</strong><br>University of Wolverhampton<br>United Kingdom</td> <td><img src="/public/site/images/mjst_admin/Dr._Nwagboso_2.jpg" width="130" height="130"><br><strong>Christopher O. Nwagboso, Ph.D.</strong><br>University of Wolverhampton<br>United Kingdom</td> </tr> <tr> <td><img src="/public/site/images/mjst_admin/Dr._Raheem_.jpg" width="130" height="130"><br><strong>Shehata&nbsp;Eldabie&nbsp;A. Raheem, Dr.Eng.</strong><br>Assiut University<br>Egypt</td> <td><img src="/public/site/images/mjst_admin/Dr._Gogi_.jpg" width="130" height="130"><br><strong>Muhammad D. Gogi, Ph.D.</strong>&nbsp;<br>University of Agriculture, Faisalabad<br>Pakistan</td> </tr> </tbody> </table> </div> </div> </div> https://mjst.ustp.edu.ph/index.php/mjst/article/view/377 Enhancing Graft-Take Success in Jackfruit (Artocarpus heterophyllus Lam.) Var. “EVIARC Sweet” Seedlings by Pre-Grafting Treatments 2020-06-04T23:46:22+00:00 Jasper A. Basalo asper_18sanctuary@yahoo.com Dario P. Lina jasper_18sanctuary@yahoo.com <p>The effects of different pre-grafting treatments in enhancing graft-take success in jackfruit seedlings were evaluated. This study aimed to assess the effects of wounding in reducing latex in rootstock and the effects of cold temperature and flowing water as scion pre-grafting treatments. The study was laid out in 2 x 3 factorial experiment arranged in randomized complete block design (RCBD) with three replications. The treatments were composed of different rootstock and scion pre-grafting treatments. Days from grafting to shoot and leaf emergence, percent graft-take, number of leaves, average numbers of shoots per grafted seedling, moisture content of the medium, chemical properties of the scion, chemical properties of the potting medium and agroclimatic data were gathered and subjected to analysis of variance for RCBD. The results revealed that the highest percent graft-take (55%) was obtained from unwounded rootstocks grafted with pre-cured scions with flowing water treatment. Lowest percent graft-take (38.33%) was achieved by wounded rootstocks grafted with pre-cured scions under cold temperature treatment. Pre-cured scions without pregrafting treatment and pre-cured scion with flowing water,regardless of the rootstocks used,revealed the lowest number of days to shoot and leaf emergence. On the contrary, pre-cured scions subjected to cold temperature showed the highest number of days for the shoot and leaf to emerge. Moreover, pre-cured scion with flowing water gave significantly the highest number of shoots and leaves, while pre-cured scions without pre-grafting and cold temperature treatment showed the lowest number of shoots and leaves.</p> 2020-05-27T00:00:00+00:00 ##submission.copyrightStatement## https://mjst.ustp.edu.ph/index.php/mjst/article/view/378 A Comparative Analysis of Techno-Economic Viability of Hybrid Renewable Systems as Sustainable Alternative for Energizing Selected Base Transceiver Station in Ogun State, Nigeria 2020-06-04T23:53:56+00:00 Ignatius K. Okakwu igokakwu@yahoo.com Olakunle E. Olabode igokakwu@yahoo.com Akintunde S. Alayande igokakwu@yahoo.com Olanike O. Ade-Ikuesan igokakwu@yahoo.com Adedoyin M. Sulaiman igokakwu@yahoo.com <p>This paper presents a comparative analysis of techno-economic viability of four different system configurations (photovoltaic [PV]/diesel generator [DG], PV/battery [BAT], DG/BAT and DG-only) for energizing outdoor telecommunication sites located within the latitude 7.15˚N and longitude 3.35˚E of Abeokuta, Ogun State, Nigeria. The site used in this study has a maximum and average load of 1697 W and 39.6 kWh/day, respectively. Among all configurations examined, PV/BAT system configuration achieved the lowest life cycle cost (LCC) of ₦133,064,109 and cost of energy (COE) of ₦0.70 with a renewable fraction of 100%, adjured as the most cost-benefit configuration. However, the configuration with the least initial capital cost of ₦4,375,000 (DG-only) was the worst system configuration due to its high LCC (₦593,667,359) and COE (₦12.95). Suffice it to know that both high fuel consumption and exorbitant cost of maintenance account for this unfavorable scenario of DG-only system configuration. In line with the results obtained, it is unarguable that the system configuration with least initial capital cost might not be necessarily be the most suitable system configuration for any proposed telecommunication site. Conclusively, hybrid renewable system configuration showed superior performance relative to the long-used orthodox DG-only system.</p> 2020-05-27T00:00:00+00:00 ##submission.copyrightStatement## https://mjst.ustp.edu.ph/index.php/mjst/article/view/379 Design, Construction, and Effectiveness of Electrical Outlet Box with Built-in High and Low Voltage Cut-off and Power-on Delay Circuit 2020-06-04T02:48:08+00:00 Jeff. L. Homeres jeff.homeres@evsu.edu.ph <p>The electrical outlets installed in houses and buildings have no means of protection to prevent the plugged-in electrical appliances from the risk of being hit by the voltage fluctuations, and sudden loss and recurrence of electricity. This study designed and constructed an electrical outlet box that disconnects the appliance from the power source when high and low voltage levels occurs. It also delays the connection to the power source at normal voltage level. It comprises a plastic enclosure securing therein the interconnections of a power supply circuit, a high and low voltage cut-off circuit, a power-on delay circuit, a relay driver circuit, a double pole double throw relay switch, and electrical outlet. The variable alternating current transformer was used to apply the high and low voltage levels to the electrical outlet box where the industrial fan was plugged. Results showed that the electrical outlet box disconnected the industrial fan from the power source at 231 and 199 V. Also, there was a four-minute waiting period before the industrial fan was connected to the power source when the 201-229 V was applied. Therefore, this device is effective in preventing appliances from being hit by voltage fluctuations and sudden loss and recurrence of electricity.</p> 2020-05-27T00:00:00+00:00 ##submission.copyrightStatement## https://mjst.ustp.edu.ph/index.php/mjst/article/view/381 Slope Stability Analysis for Deterministic Shallow Landslide Assessment and Mapping: A Case Study in Kibawe, Bukidnon 2020-06-04T23:55:30+00:00 Vera Karla S. Caingles khaicaingles@yahoo.com.ph Glen A. Lorenzo khaicaingles@yahoo.com.ph <p>The slope’s stability in mountainous or hilly region is significantly important for the safety and protection of the people and the environment. Intensive field sampling was carried out in the study sites at Kibawe, Bukidnon, Philippines and soil samples were subjected to laboratory tests. The study applied the deterministic method through slope stability analysis to calculate the factor of safety (FOS) for landslide assessment. It also used Geographic Information System (GIS) particularly the ArcGIS software for FOS mapping. The results revealed that the study sites have mostly inorganic but highly expansive fine-grained soils. The values of the FOS varied in each steady-state condition. For fully-saturated and dry conditions, the values ranged from 1.54-9.98 and 1.94-12.66, respectively. For partially-saturated condition where m = 0.75, m = 0.5 and m = 0.25, the values of FOS ranged from 1.65-10.65; 1.74-11.32; and 1.84- 11.99, respectively. In general, the FOS values signified that the study area was stable against sliding; however, there was a considerable decrease in FOS values when the slope changed from completely dry to fully-saturated condition. The created set of FOS maps lay out a visual impression and the variation of slope stability condition in the study area. The findings provide a baseline reference study for the area’s slope stability that is essential in planning or further assessment of the study area. Furthermore, this can be directly used by the local government for land-use planning and future development.</p> 2020-05-29T00:00:00+00:00 ##submission.copyrightStatement## https://mjst.ustp.edu.ph/index.php/mjst/article/view/382 Large-Scale Prototype Testing of a Composite Geosynthetics Reinforced Earth Structure for Riverbank Slope Protection Using Fine Grained Sandy Soil 2020-06-04T03:20:40+00:00 Ulmen Riff L. Circulado engr.urlc@gmail.com Glen A. Lorenzo engr.urlc@gmail.com <p>This paper presents the field evaluation of large scale prototypes of an innovative composite geosynthetic reinforced earth (CGRE) structure as an alternative for the conventional earth retaining structures, hence a green engineering design for riverbank slope protection. This reinforced earth structure comprises of a geogrid that serves as the main reinforcement and the cover of the facing member of the structure; and a geotextile as separator medium between the infill soil and intermediate horizontal gravel drainage. Three large scale prototypes at full, half, and no gravel drainage were built, monitored, and tested. Clayey sand soil was the fill material used and a 3/2” to 2” sub-rounded gravel was used for the drainage and facing members. CGRE prototypes were evaluated in saturated conditions, and tested under incremental surcharge loadings with a total applied stress of 40 kPa. Lateral displacements for every layer of the structure were determined using horizontal rods where readings were taken from line gauges. Results showed that prototypes with gravel drainage displaced lower than the permissible limit of 4.0%. The CGRE prototype with full gravel drainage had the smallest average total lateral displacement of 1.28%. Hence, it had a higher interface friction resistance, and pull-out capacity than the one with less or no gravel drainage. Overall, the incorporation of gravel drainage improved the performance of the reinforced earth system by reducing the lateral movements of the structure. Therefore, the CGRE structure is a viable slope protection alternative even under saturated conditions</p> 2020-05-29T00:00:00+00:00 ##submission.copyrightStatement## https://mjst.ustp.edu.ph/index.php/mjst/article/view/383 Site-Specific Response Spectra: 2nd District of Cagayan de Oro City, Philippines 2020-06-04T03:21:37+00:00 Israel A. Baguhin israel.baguhin@ustp.edu.ph Jerson N. Orejudos israel.baguhin@ustp.edu.ph <p>Building codes are updated advertently to address the catastrophic effect of earthquakes. One way of mitigating it is the development of a site-specific response spectrum. In the Philippines, the National Structural Code of the Philippines (NPSC) is the recognized National Building Code adopting the 1997 Uniform Building Code (UBC). The NSCP uses the 10% probability of exceedance in a 50-year period with a return period of 475 years. In this study, site-specific response spectra were developed in the 2nd District of Cagayan de Oro City using a 300-km radius, with coordinates of 8.235° (latitude) and 124.024° (longitude) as the center point of the study area, using the same probability of exceedance in a 50-year period. Historical earthquake catalogs were gathered from the United States Geological Survey and the Department of Science and Technology – Philippine Institute of Volcanology and Seismology. Local soil condition was assimilated in the study to take into account the soil response. Finally, site-specific response spectra were developed using the probabilistic seismic hazard analysis where substantial results are achieved, i.e., the UBC 1997 design response spectrum is remarkably high in spectral acceleration values at 0.01, 0.20, 1.0, 2.0, 3.0, 4.0 and 5.0 s at 0.44, 1.1, 1.1, 0.7, 0.36, 0.26 and 0.20 g compared to the maximum site-specific response spectra of the study area of the same period at 0.39, 0.92, 0.23, 0.10, 0.07, 0.05 and 0.04 g spectral accelerations, respectively.</p> 2020-05-29T06:24:57+00:00 ##submission.copyrightStatement## https://mjst.ustp.edu.ph/index.php/mjst/article/view/384 Development and Use of Antimicrobial Durian Starch-Carrageenan/Carvacrol Films 2020-06-04T03:22:32+00:00 Elizabeth Marie Z. Velasco nvfundador@up.edu.ph Noreen Grace V. Fundador nvfundador@up.edu.ph <p>Durian starch (DS) was isolated from durian seeds by aqueous extraction with 0.5% NaHSO3. The percent yield and purity of the starch were 11.42 and 42%, respectively. The DS-carrageenan (CG) films containing different concentrations (0, 4, 6, 8, and 10%) of carvacrol were prepared. The antimicrobial activity of the DS-CG/carvacrol films was evaluated against Staphylococcus aureus BIOTECH 1582 using disk diffusion assay. Results revealed that the zone of inhibition increased with carvacrol concentration and application of prediffusion treatment. Films containing 8% carvacrol had a zone of inhibition of 15.89 mm. The DS-CG/carvacrol films were found effective in controlling the growth of S. aureus in commercial durian candy. After 24 h of storage at 4 °C, the microbial count was reduced by 0.79 log cycle (83.6% reduction). The findings of this research suggest the potential of the DS-CG/carvacrol films as an active biodegradable packaging system to prevent the growth of S. aureus.</p> 2020-05-29T00:00:00+00:00 ##submission.copyrightStatement## https://mjst.ustp.edu.ph/index.php/mjst/article/view/385 eCarte: An Interactive Restaurant Menu with Feedback Collection 2020-06-04T03:23:40+00:00 Kristian Andrew R. Romano urielmelendres@gmail.com Rheabel S. Masilungan urielmelendres@gmail.com Ladelyn Cacho urielmelendres@gmail.com Uriel M. Melendres urielmelendres@gmail.com <p>The restaurant industry has grown over the years along with the modernization of technology. Like any other area of this industry, the menu presentation also demands improvement. Possessing smartphones proved to be a necessity nowadays and regular restaurant customers with their phones bring an opportunity to materialize the concept. The idea of accessing the restaurant menu through smartphones is new to a restaurant in Oriental Mindoro, Philippines. Hence, the proponents were motivated to develop the eCarte – an interactive restaurant menu with feedback collection. The development of this system can improve the customer's experience which would be beneficial to the restaurant. Proponents used incremental development as a software development method to come up with an efficient system. The developed system is userfriendly and interactive. The customers will be able to see the actual picture of the dish with a short description, and other customers’ reviews. Selected Information Technology Faculty, restaurant owners and customers evaluated the system. The five evaluation criteria used were adapted from ISO 25010 software quality standards. Based on the evaluation result, eCarte is usable and met its expected functions in terms of functional suitability (4.93), performance efficiency (4.88), usability (4.84), security (4.83), and maintainability (4.84). The system is generic, not expensive, easy to maintain and suitable to any smartphone regardless of its operating system which makes it applicable to any local restaurant. For further improvement, the proponent recommends applying an algorithm like the High Adjective Count algorithm and Max Opinion Score algorithm to effectively analyze the customer's feedback.</p> 2020-05-29T00:00:00+00:00 ##submission.copyrightStatement## https://mjst.ustp.edu.ph/index.php/mjst/article/view/386 Acoustic Characterization of Retrofit Vertical Duct Soundproof Enclosure for Portable Mini-Generators 2020-06-04T03:24:38+00:00 Cornelius O. A. Agbo cornelius.agbo@unn.edu.ng <p>Environmental noise pollution from electric power generators has become seemingly intractable in most developing countries due to the epileptic power supply. Families as well as corporate organizations now rely on these standby generators for their daily electricity needs. The concern of this paper was the characterization of the developed vertical duct soundproof acoustic enclosure on mitigating the noise produced by portable mini generators. A total of six acoustic parallelepiped boxes were produced using chopped strand E-glass fiber mat reinforced composite panels with polyurethane foam inner lining. The generator noise spectra with and without the enclosure were obtained for comparative analysis. The sound pressure level of the generator noise at each enclosure height was also measured. It was found out that the noise level reduced by 12.8 dBA when the sound pressure levels at both conditions were taken and compared at optimal enclosure height (1600 mm). The result from exhaust ducting showed that exhaust duct projection, channeling out the fumes, did not significantly impact the enclosure insertion loss. The enclosure and the generator were also found to be in stable, acceptable thermal conditions while operating at rated load with a maximum temperature of 39 °C measured inside the enclosure. This eliminates the need for artificial cooling and its consequent power drain.</p> 2020-05-29T00:00:00+00:00 ##submission.copyrightStatement## https://mjst.ustp.edu.ph/index.php/mjst/article/view/387 Low-Cost Garbage Level Monitoring System in Drainages Using Internet of Things in the Philippines 2020-06-04T03:28:30+00:00 Rio Allen G. Parilla junjunobiso@gmail.com Oliver Joseph C. Leorna junjunobiso@gmail.com Roces Dave P. Attos junjunobiso@gmail.com Maria Gemel B. Palconit junjunobiso@gmail.com Jun-Jun A. Obiso junjunobiso@gmail.com <p>A common problem in a developing tropical country like the Philippines is the flooding during downpours. One of the causes is the clogging of drainages due to garbage accumulation, which results in overflowing. A countermeasure to minimize this problem is the deployment of an internet of things-based garbage monitoring system. In this system, the ultrasonic sensors were used to provide input data on the level of the garbage in the drainage. These data were then transmitted to the web application for visualization. A message, informing the status of the garbage level in real-time, was sent to the registered user. Also, a strainer was used to serve as a stopper of the accumulated garbage in the drainage. This strainer was set up in the middle of the manhole so that the detected level of garbage and water would be compared. In addition, the ultrasonic sensors were mounted on the top and the back of the strainer to detect the garbage level and serve as a comparative sensor, respectively. Furthermore, to assess the performance of the developed system, several tests were conducted in Cebu City, Philippines. These tests included the short message service delay, internet speed, and the garbage level. The results showed that the developed system can effectively deliver its desired operations. However, since the system is reliant on internet connectivity, it is highly recommended to use such in a 5G network.</p> 2020-05-29T00:00:00+00:00 ##submission.copyrightStatement## https://mjst.ustp.edu.ph/index.php/mjst/article/view/391 Experimental Laboratory Investigation on the Threshold of Soil Saturation and Profile on Slopes Prone to Extended Rains 2020-06-04T23:57:38+00:00 Emmanuel B. Barbas emmb_123@rocketmail.com Glen A. Lorenzo emmb_123@rocketmail.com <p>The increase in the degree of soil saturation by rainwater infiltration is detrimental to the stability of slopes. For an accurate assessment of the potential triggering of rainfall-induced slope instabilities, the use of analytical assessment methods must be complemented with more precise information regarding the dynamic saturation behavior of the investigated soil. To obtain such soil-specific data, this study conducted a series of laboratory saturation simulations by exposing the variably sloped soil sample to artificial rains of moderate and typhoon-patterned intensities. The recorded data were consolidated to profile the temporal saturation responses of the soil, provide empirical equations for estimation of the normal movement of the infiltration front, and determine the saturation threshold of the tested soil. Based on the results, it was found out that the wettest possible soil state could be attained under partially saturated conditions but only for gentle slopes of up to 20°. The fully saturated zone originated at the bottom as opposed to the wetting front concept. For steeper slopes of 30° and above, surface runoff was more dominant that the infiltrated water could barely increase the soil moisture content at a depth of 0.626 m by less than 5%. High saturation thresholds were observed at the bottom (0.626 m depth) at values ranging from 83.7 to 99.7%.</p> 2020-05-31T00:00:00+00:00 ##submission.copyrightStatement## https://mjst.ustp.edu.ph/index.php/mjst/article/view/392 Landscape and Soil Characteristics of LandslideAffected Cadac-an Watershed in Leyte, Philippines 2020-06-04T23:58:56+00:00 Jorge P. Cabelin, Jr. cabelinjorge@gmail.com Beatriz C. Jadina cabelinjorge@gmail.com <p>The continuous and increasing degradation problem in Leyte watershed due to landslide occurrences explains the importance of the characterization of these areas. Hence, this study was carried out to characterize the landscape and soil properties in the landslide-prone watershed. Landslide cuts, serving as representative soil profiles in Cadac-an watershed, were used for examination and characterization. Among the landscape characteristics determined were fault line, geomorphology and land use. Profiles were sampled for the analyses of soil properties such pH (Potentiometric method), percent organic matter (OM) (loss of weight on ignition), available phosphorus (P) (Olsen extraction method), cation exchange capacity (CEC) (ammonium acetate method) and exchangeable bases: calcium (Ca), magnesium (Mg), sodium (Na), and potassium (K). Cadac-an watershed was observed to be dominated by andesitic materials characterized by the presence of the active Leyte segment of the Philippine Fault. It is rugged and mountainous with brushes and grasses as the dominant vegetation. Generally, soils from the landslide areas in Cadac-an watershed had a very strongly acidic to moderately alkaline pH, high to low OM and P content, very high to low CEC, high to low exchangeable K, Ca and Mg, and low exchangeable Na.</p> 2020-05-31T00:00:00+00:00 ##submission.copyrightStatement## https://mjst.ustp.edu.ph/index.php/mjst/article/view/393 Insights into Compatibilization of Poly(ε-caprolactone)-based Biocomposites with Diisocyanates as Modifiers of Cellulose Fillers 2020-06-05T00:32:03+00:00 Aleksander Hejna aleksander.hejna@pg.edu.pl Paulina Kosmela aleksander.hejna@pg.edu.pl <p>This study aimed to analyze the impact of cellulose fillers’ modification with diisocyanates on the performance of composites based on the poly(ε-caprolactone) (PCL) matrix. Four most commonly used diisocyantes (isophorone, hexamethylene, toluene, and methylene diphenyl) were applied as modifiers of cellulose fillers (5 and 15 wt% per mass of filler). Modified fillers were introduced in the amount of 30 wt% into the PCL matrix. Chemical structure, thermal, static and dynamic mechanical properties of composites were investigated using Fourier transform infrared spectroscopy, differential scanning calorimetry, tensile, hardness and rebound resilience tests, and dynamic mechanical analysis, respectively. Modifications of cellulosic fillers resulted in the decrease of matrix crystallinity and enhancement of interfacial interactions, causing even a two-fold increase of tensile strength and a 25% rise of modulus. These results indicate that through proper adjustment of type and content of diisocyanate modifier, composites’ properties may be engineered.</p> <p>&nbsp;</p> 2020-05-31T00:00:00+00:00 ##submission.copyrightStatement## https://mjst.ustp.edu.ph/index.php/mjst/article/view/395 Performance of Dye-Sensitized Solar Cells with Natural Dye from Local Tropical Plants 2020-06-03T02:09:23+00:00 Gee Jay C. Bartolome al.torres3154@gmail.com Jhon Patrick S. de Mesa al.torres3154@gmail.com Judy Ann C. Adoña al.torres3154@gmail.com Al Eugene L. Torres al.torres3154@gmail.com <p>Dye-sensitized solar cell (DSSC) is a class of third generation solar cells that are formed by placing a semiconductor between a photosensitized anode and an electrolyte, which allows the light to pass through the cell. Synthetic dyes, usually ruthenium-based and commonly used in DSSCs, are environmentally toxic and expensive than natural dyes. The aim of the study was to investigate native and cheap sources of natural dyes as photosensitizers for DSSCs using tropical plants. Dyes from four different local plant sources were successfully extracted, prepared, and characterized and were used as alternative, non-toxic, natural photosensitizers. The visible spectra of the extracts with peaks between 430-440 nm suggest that they are dominated by chlorophyll a (430-662 nm) and chlorophyll b (453-642 nm). When observed under ambient conditions, the fabricated DSSCs demonstrated high outputs for OCVmax wherein 433, 397, 311, and 203 mV were obtained using dye-sensitizers from dried talisay leaves (Terminalla catappa), spent coffee grounds (Coffea spp.), fresh talisay leaves, and alugbati fruit (Basella alba), respectively. The observed open circuit potentials were comparable with other reported DSSCs. The output current, fill factor, and cell efficiency can be improved by co-sensitization and increasing the lightscattering capability, among other methods of constructing the DSSCs. Generally, with the limited impacts to the environment and cheap production cost, this research has opened opportunities for application of natural dye from local sources for renewable energy technologies.</p> 2020-05-31T00:00:00+00:00 ##submission.copyrightStatement##