scholarly journals Three-Dimensional Magnetotelluric (MT) Modeling of the Northern Negros Geothermal Project, Central Philippines

2021 ◽  
Author(s):  
◽  
Carlos Emmanuel Fajardo Los Banos
Keyword(s):  
High Temperature ◽  
Bottom Layer ◽  
The Philippines ◽  
Conductive Layer ◽  
Resistivity Structure ◽  
Resistive Layer ◽  
Transient Electromagnetic ◽  
Phase Tensor ◽  
Short Period ◽  
Alteration Minerals

<p>The latest magnetotelluric (MT) survey was conducted in the Northern Negros Geothermal Project (NNGP), which is one of the geothermal fields being developed in the Philippines, from December, 2010 to April, 2011. 66 new MT soundings were added to the previous MT dataset. The new stations were located mainly in the southeastern and southern regions to define the extent of drilled high-temperature resource in these areas.  Phase tensor analysis show that the MT data in general is only 1-D in the short period range of <1 s and becomes 3-D at longer periods. 1-D, 2-D and 3-D modeling were performed on the MT dataset after stripping it for distortion based on the phase tensor and correcting for static shifts using Transient Electromagnetic (TEM) data. The resistivity structure from all models show three main layers: a >100 ohm-m resistive top layer, a middle <10 ohm-m conductive layer and a >20 ohm-m moderately resistive bottom layer. The highly resistive top layer is associated with the relatively fresh volcanic deposits of the Canlaon Volcanics (CnV). Correlating the 3-D resistivity structure with subsurface data from the drilled wells shows that the thick conductive layer overlaps with the low-temperature alteration minerals such as smectite while the moderately resistive bottom layer coincides with the high-temperature alteration minerals like illite and epidote. These observations are also consistent with the measured well temperatures wherein the elevated temperatures drilled beneath the Pataan sector coincide with the shallow occurence or doming portion of the bottom resistive layer.  Tracing the shallow occurrence of the bottom resistive layer revealed a northeast extension to the drilled resource beneath Pataan. The delineated resource area in Pataan is about 3 to 7 km².  Other possible high-temperature areas are located within the Upper Hagdan and Hardin Sang Balo sectors. However, resolution of the resistivity structure is not well pronounced in these areas due to limited data coverage.</p>

scholarly journals Three-Dimensional Magnetotelluric (MT) Modeling of the Northern Negros Geothermal Project, Central Philippines

2021 ◽  
Author(s):  
◽  
Carlos Emmanuel Fajardo Los Banos
Keyword(s):  
High Temperature ◽  
Bottom Layer ◽  
The Philippines ◽  
Conductive Layer ◽  
Resistivity Structure ◽  
Resistive Layer ◽  
Transient Electromagnetic ◽  
Phase Tensor ◽  
Short Period ◽  
Alteration Minerals

<p>The latest magnetotelluric (MT) survey was conducted in the Northern Negros Geothermal Project (NNGP), which is one of the geothermal fields being developed in the Philippines, from December, 2010 to April, 2011. 66 new MT soundings were added to the previous MT dataset. The new stations were located mainly in the southeastern and southern regions to define the extent of drilled high-temperature resource in these areas.  Phase tensor analysis show that the MT data in general is only 1-D in the short period range of <1 s and becomes 3-D at longer periods. 1-D, 2-D and 3-D modeling were performed on the MT dataset after stripping it for distortion based on the phase tensor and correcting for static shifts using Transient Electromagnetic (TEM) data. The resistivity structure from all models show three main layers: a >100 ohm-m resistive top layer, a middle <10 ohm-m conductive layer and a >20 ohm-m moderately resistive bottom layer. The highly resistive top layer is associated with the relatively fresh volcanic deposits of the Canlaon Volcanics (CnV). Correlating the 3-D resistivity structure with subsurface data from the drilled wells shows that the thick conductive layer overlaps with the low-temperature alteration minerals such as smectite while the moderately resistive bottom layer coincides with the high-temperature alteration minerals like illite and epidote. These observations are also consistent with the measured well temperatures wherein the elevated temperatures drilled beneath the Pataan sector coincide with the shallow occurence or doming portion of the bottom resistive layer.  Tracing the shallow occurrence of the bottom resistive layer revealed a northeast extension to the drilled resource beneath Pataan. The delineated resource area in Pataan is about 3 to 7 km².  Other possible high-temperature areas are located within the Upper Hagdan and Hardin Sang Balo sectors. However, resolution of the resistivity structure is not well pronounced in these areas due to limited data coverage.</p>

Permafrost mapping by audiofrequency magnetotellurics

1978 ◽  
Vol 15 (10) ◽  
pp. 1539-1546 ◽  
Author(s):  
A. Koziar ◽  
D. W. Strangway
Keyword(s):  
Mackenzie Delta ◽  
Conductive Layer ◽  
Frequency Range ◽  
Layer Model ◽  
Resistive Layer ◽  
Asymptotic Models ◽  
Two Layer Model ◽  
Electrical Methods ◽  
Permafrost Mapping ◽  
Lateral Variations

The audiofrequency magnetotelluric (AMT) method has been used to study permafrost thickness near Tuktoyaktuk, N.W.T. in the Mackenzie Delta. In the frequency range of 10 Hz–10 kHz the permafrost behaves as a simple resistive layer over a conductive layer. This simple two-layer model can be inverted by asymptotic models to give a unique value for the thickness of the highly resistive frozen layer. In areas of simple layering, these results correlate well with drilling. In areas of sharp lateral variations in resistivity, depths tend to be underestimated. Unlike other electrical methods, AMT is not hampered by the presence of a surface melt layer in the summer if the conductivity–thickness product of this 'active layer' is less than about 0.03 mho (0.03 S).

Behavioural aspects of microhabitat segregation of different age stages in the wetland land snail Vertigo moulinsiana (Eupulmonata: Vertiginidae) in the laboratory

2020 ◽  
Vol 86 (3) ◽  
pp. 228-232
Author(s):  
Zofia Książkiewicz-Parulska
Keyword(s):  
High Temperature ◽  
Land Snail ◽  
Snail Species ◽  
High Humidity ◽  
Short Period ◽  
Temperature And Humidity ◽  
In The Wild ◽  
Different Response ◽  
Behavioural Aspects ◽  
Microhabitat Segregation

ABSTRACT This laboratory study investigated behavioural differences between adults and juveniles of the wetland land snail species Vertigo moulinsiana with respect to temperature and humidity. Juveniles of V. moulinsiana, for example, tend to remain within the shaded, humid and cool layer of the litter, while adults usually climb above wet vegetation to a height of over 2 m. Adults are thus exposed to greater variation in temperature and humidity than juveniles. My experiments showed that adults of V. moulinsiana remain active longer than juveniles when subject to high temperature (36 °C) and low relative humidity (RH 30%). Conversely, juveniles stay active longer than adults in high humidity (22 °C, RH 100%). A short period of starvation lengthened the time needed for the juveniles to become active after dormancy, possibly indicating a different response between adults and juveniles to lack of nutritional reserves. These behavioural differences to food availability and the risk of water loss correspond to the microhabitat differences observed between adults and juveniles in the wild.

Seed Germination Ecology of Itchgrass (Rottboellia cochinchinensis)

Weed Science ◽  
2011 ◽  
Vol 59 (2) ◽  
pp. 182-187 ◽  
Author(s):  
Grace E-K. Bolfrey-Arku ◽  
Bhagirath S. Chauhan ◽  
David E. Johnson
Keyword(s):  
High Temperature ◽  
Seed Germination ◽  
Seedling Emergence ◽  
Soil Surface ◽  
The Philippines ◽  
Integrated Weed Management ◽  
Burial Depth ◽  
Soil Burial ◽  
Dark Regime ◽  
Temperature Pretreatment

Itchgrass is a weed of many crops throughout the tropics and one of the most important grass weeds of rainfed rice. Experiments were conducted in the laboratory and screenhouse to determine the effects of light, alternating day/night temperatures, high temperature pretreatment, water stress, seed burial depth, and rice residue on seed germination and seedling emergence of itchgrass in the Philippines. Two populations were evaluated and the results were consistent for both populations. Germination in the light/dark regime was greater at alternating day/night temperatures of 25/15 C than at 35/25, 30/20, or 20/10 C. Light was not a requirement for germination, but a light/dark regime increased germination by 96%, across temperature and population. A 5-min high temperature pretreatment for 50% inhibition of maximum itchgrass germination ranged from 145 to 151 C with no germination when seeds were exposed to ≥ 180 C. The osmotic potential required for 50% inhibition of maximum germination was −0.6 MPa for itchgrass, although some seeds germinated at −0.8 MPa. Seedling emergence was greatest for seeds placed on the soil surface, and emergence declined with increasing soil burial depth; no seedlings emerged from seeds buried at 10 cm. The addition of rice residue to soil surface in pots at rates equivalent to 4 to 6 Mg ha−1reduced itchgrass seedling emergence. Since seedling emergence was greatest at shallow depths and germination was stimulated by light, itchgrass may become a problem in systems where soil is cultivated at shallow depths. Knowledge gained in this study could contribute to developing components of integrated weed management strategies for itchgrass.

scholarly journals Beach sands deposite identification using very low frequency method in the Benteng Lubuk, Krueng Raya coastal area

2021 ◽  
Vol 869 (1) ◽  
pp. 012058
Author(s):  
M Jannah ◽  
M Muhammad ◽  
Marwan ◽  
Z Jalil
Keyword(s):  
Sea Water ◽  
Low Frequency ◽  
High Resistivity ◽  
Conductive Layer ◽  
Inversion Process ◽  
Frequency Method ◽  
Sea Water Intrusion ◽  
Resistive Layer ◽  
Very Low Frequency ◽  
Beach Sands

Abstract The 2D subsurface identification work of iron sands in Benteng Lubuk, Krueng Raya was successfully studied using the very low frequency method based on resistivity mode (VLF-R). This study aims to identify iron sand deposits in coastal areas using electromagnetic inversion. The inversion process shows a conductivity zone of iron sand area, where the resistive layer is strongly covered by a conductive layer above it. High resistivity values were found at 80-100 m stations. This layer has a resistivity value between 20000 – 40000 m and the conductivity value tend to be low. It is estimated that at this point there will only be manifestations of iron sand or sea water intrusion, due to the location of the track close to the coastline.

Characterization of Ti/TiN and TiN Conductive Layer for High Temperature MEMS Devices

2005 ◽  
Vol 872 ◽  
Author(s):  
Peter Lange ◽  
Birger Ohlsen ◽  
Sebastian Puls ◽  
Joerg Syre
Keyword(s):  
Thermal Stability ◽  
High Temperature ◽  
Elevated Temperature ◽  
Mechanical Stability ◽  
Fast Response ◽  
Conductive Layer ◽  
Mems Devices ◽  
Thermal Isolation ◽  
Effects Of Temperature

AbstractThe effects of temperature on micro heaters made of Ti/TiN stacks and pure TiN layers on bulk micromachined membranes have been studied. Ti/TiN stacks show a thermal stability up to 380°C, beyond that temperature an enhanced interaction within the stack and/or with adjacend layers leads to a degradation of the resistance. The pure TiN layers withstand temperatures up to 600 °C, this limitation is only given by the mechanical stability of the membran stack, which is destroyed beyond this temperature. These layers are suitable for sensors in which an elevated temperature provided by heating lines on a membran for thermal isolation and fast response is necessary for functionality.

scholarly journals High Temperature Structure in Cool Binary Stars

1996 ◽  
Vol 152 ◽  
pp. 141-145
Author(s):  
A.K. Dupree ◽  
N.S. Brickhouse ◽  
G.J. Hanson
Keyword(s):  
High Temperature ◽  
Binary Stars ◽  
Binary Systems ◽  
Emission Measure ◽  
Temperature Structure ◽  
Differential Emission Measure ◽  
Absolute Size ◽  
Hot Plasma ◽  
Short Period ◽  
Different Temperatures

Strong high temperature emission lines in the EUVE spectra of binary stars containing cool components (Alpha Aur [Capella], 44ι Boo, Lambda And, and VY Ari) provide the basis to define reliably the differential emission measure of hot plasma. The emission measure distributions for the short-period (P ≤ 13 d) binary systems show a high temperature enhancement over a relatively narrow temperature region similar to that originally found in Capella (Dupree et al. 1993). The emission measure distributions of rapidly rotating single stars 31 Com and AB Dor also contain a local enhancement of the emission measure although at different temperatures and width from Capella, suggesting that the enhancement in these objects may be characteristic of rapid rotation of a stellar corona. This feature might be identified with a (polar) active region, although its density and absolute size are unknown; in the binaries Capella and VY Ari, the feature is narrow and it may arise from an interaction region between the components.

scholarly journals How Do Millennial Managers Lead Older Employees? The Philippine Workplace Experience

SAGE Open ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 215824402091465
Author(s):  
Arneil G. Gabriel ◽  
Gloria M. Alcantara ◽  
Josephina D. G. Alvarez
Keyword(s):  
Leadership Styles ◽  
Participant Observation ◽  
The Philippines ◽  
Factors Affecting ◽  
Leadership Attributes ◽  
Older Employees ◽  
Global Workforce ◽  
Workplace Experience ◽  
Short Period ◽  
And Performance

As millennial workers enter and dominate the global workforce by 2025, understanding their leadership styles is vital to bring about higher level of performance and productivity in the workplace. The Millennials, the next generation of leaders, are entering the workforce and assuming leadership positions in a relatively short period. More often, they found themselves leading employees that are older than themselves and yet their leadership traits and styles are not fully understood. The study explores factors affecting leadership styles of millennial managers and how they are manifested and applied in managing and resolving conflict involving older subordinates. Using a qualitative approach, it employs interviews, participant observation, and prolonged engagement with four millennial managers from the National Food Authority in the Philippines as they lead, manage, and interact with their older staff. Data collected were triangulated by document analysis and interview of the millennial managers’ subordinates themselves. The results of the study show that the participants’ leadership competencies are in the early stages of development. The participants consider building good impression and rapport highlighting the importance of soft skills in leadership, strong sense of respect, reverse mentoring, delegation of tasks, and the ability to handle expectations and performance as factors in managing older employees. This study draws the attention to examining the leadership attributes and potentials of Filipino millennial managers in the context of Philippine workplace culture using insights from Public Administration, Social Sciences, and Psychology.

Spatial averaging of the vertical magnetic field in central‐loop configuration

Geophysics ◽  
1993 ◽  
Vol 58 (10) ◽  
pp. 1507-1510 ◽  
Author(s):  
Wei Qian ◽  
Laust B. Pedersen
Keyword(s):  
Tensor Decomposition ◽  
Data Interpretation ◽  
Impedance Tensor ◽  
Logarithmic Scale ◽  
Resistivity Structure ◽  
One Dimensional ◽  
Transient Electromagnetic ◽  
The Earth ◽  
Band Limited ◽  
Central Loop

Local resistivity heterogeneities can cause static shifts in the magnetotelluric (MT) impedance tensor that severely complicate data interpretation; the apparent resistivity is shifted on a logarithmic scale across the recorded frequency range while the phase has a band‐limited response. Different techniques such as electromagnetic array profiling (EMAP) (Torres‐Verdín and Bostick, 1992) and tensor decomposition (Zhang et al., 1987; Groom and Bailey, 1989; 1991) have been developed in the MT community to recognize and remove static shifts. Sternberg, et al. (1988) and Pellerin and Hohmann (1990) suggest that central‐loop transient electromagnetic (TEM) soundings can obtain an unbiased estimate of the regional resistivity structure of the earth and thereby correct for magnetotelluric static shifts. The regional resistivity structure of the earth must be one‐dimensional (1-D) for this method to work well.

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