scholarly journals GIS-BASED THERMAL LOAD ESTIMATION OF BUILDINGS IN THE NATIONAL SCIENCE COMPLEX, UP DILIMAN

2021 ◽  
Vol XLVI-4/W6-2021 ◽  
pp. 289-294
Author(s):  
C. A. Tatlonghari ◽  
J. A. Principe
Keyword(s):  
Thermal Load ◽  
Fossil Fuels ◽  
The Philippines ◽  
Small Scale ◽  
Surface Model ◽  
Load Estimation ◽  
Cooling Load ◽  
National Science ◽  
Set Up ◽  
Future Work

Abstract. Building thermal load is the energy exhausted to maintain a specific indoor temperature in comparison to the outdoor temperature. Majority of this energy makes use of a considerable amount of fossil fuels which contributes to greenhouse gases emission leading to global warming. Thermal load estimation of buildings allows people to identify infrastructures in need for retrofit for a more sustainable and smart urban management. This paper presents a small-scale study to estimate the thermal cooling load of fourteen (14) buildings in the National Science Complex of the University of the Philippines Diliman. Results of the annual cooling load calculation for the year 2020 was reported with an estimated lowest cooling load of 1,618 kW for the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) observatory and the highest cooling load of 13,484 kW for the Institute of Mathematics. The values calculated was an overestimation as the entire building was set up as a homogenous cold room without any windows or doors. For future work, it is recommended that input data be supplemented with digital surface model (DSM) and triangulated irregular network (TIN) raster data derived from Light Detection and Ranging (LiDAR) to not only categorize but assign specific values over each building group of the study area.

scholarly journals Modification of a Solar Thermal Collector to Promote Heat Transfer inside an Evacuated Tube Solar Thermal Absorber

2021 ◽  
Vol 11 (9) ◽  
pp. 4100
Author(s):  
Rasa Supankanok ◽  
Sukanpirom Sriwong ◽  
Phisan Ponpo ◽  
Wei Wu ◽  
Walairat Chandra-ambhorn ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Pipe ◽  
Solar Thermal ◽  
Heat Transfer Fluid ◽  
Small Scale ◽  
Medium Temperature ◽  
Change Behavior ◽  
Set Up ◽  
Evacuated Tube ◽  
Heating Medium

Evacuated-tube solar collector (ETSC) is developed to achieve high heating medium temperature. Heat transfer fluid contained inside a copper heat pipe directly affects the heating medium temperature. A 10 mol% of ethylene-glycol in water is the heat transfer fluid in this system. The purpose of this study is to modify inner structure of the evacuated tube for promoting heat transfer through aluminum fin to the copper heat pipe by inserting stainless-steel scrubbers in the evacuated tube to increase heat conduction surface area. The experiment is set up to measure the temperature of heat transfer fluid at a heat pipe tip which is a heat exchange area between heat transfer fluid and heating medium. The vapor/ liquid equilibrium (VLE) theory is applied to investigate phase change behavior of the heat transfer fluid. Mathematical model validated with 6 experimental results is set up to investigate the performance of ETSC system and evaluate the feasibility of applying the modified ETSC in small-scale industries. The results indicate that the average temperature of heat transfer fluid in a modified tube increased to 160.32 °C which is higher than a standard tube by approximately 22 °C leading to the increase in its efficiency by 34.96%.

scholarly journals A Selective Solar Absorber for Unconcentrated Solar Thermal Panels

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 900
Author(s):  
Davide De Maio ◽  
Carmine D’Alessandro ◽  
Antonio Caldarelli ◽  
Daniela De Luca ◽  
Emiliano Di Gennaro ◽  
...  
Keyword(s):  
Fossil Fuels ◽  
High Vacuum ◽  
Optimization Procedure ◽  
Energy Transition ◽  
Spectral Emissivity ◽  
Thermal Conversion ◽  
Stagnation Temperature ◽  
Solar Absorber ◽  
Analytical Formulas ◽  
Set Up

A new Selective Solar Absorber, designed to improve the Sun-to-thermal conversion efficiency at mid temperatures in high vacuum flat thermal collectors, is presented. Efficiency has been evaluated by using analytical formulas and a numerical thermal model. Both results have been experimentally validated using a commercial absorber in a custom experimental set-up. The optimization procedure aimed at obtaining Selective Solar Absorber is presented and discussed in the case of a metal dielectric multilayer based on Cr2O3 and Ti. The importance of adopting a real spectral emissivity curve to estimate high thermal efficiency at high temperatures in a selective solar absorber is outlined. Optimized absorber multilayers can be 10% more efficient than the commercial alternative at 250 °C operating temperatures, reaching 400 °C stagnation temperature without Sun concentration confirming that high vacuum flat thermal collectors can give important contribution to the energy transition from fossil fuels to renewable energy for efficient heat production.

scholarly journals Endoscopic Pan/Tilt Camera for Thorax Interventions – Design and first results

2019 ◽  
Vol 5 (1) ◽  
pp. 517-519
Author(s):  
Alexander Mrokon ◽  
Peter P. Pott ◽  
Volker Steger
Keyword(s):  
Minimally Invasive ◽  
Inclination Angle ◽  
Magnetic Circuit ◽  
Mechanical Stability ◽  
Fem Simulation ◽  
Camera System ◽  
Design Changes ◽  
First Results ◽  
Set Up ◽  
Future Work

AbstractMinimally invasive surgery in some cases suffers from a limited view because certain areas are obscured by others. In this paper, a system is described, which can be used in minimally invasive procedures as an addition to a standard endoscope to improve the range of view. Through FEM simulation a magnetic circuit was designed to position the camera head. Subsequently, a camera positioning system was set up that includes an extracorporeal and an intracorporeal unit. The first controls the intracorporeal system. The latter has a camera inclination angle of up to 65° and an additional vertically downward viewing angle when aligned in parallel (inclination angle 0°). The panning angle is 360°. The camera system was evaluated in lab and cadaver trials. It has been found that the size of the intracorporeal system (16 × 10 × 150 mm) represents a major problem. Future work will focus of the reduction of the system’s size, the improvement of the camera image quality, and design changes considering mechanical stability.

A numerical study of the transition of jet diffusion flames

1990 ◽  
Vol 431 (1882) ◽  
pp. 301-314 ◽  
Keyword(s):  
Reynolds Number ◽  
Diffusion Coefficient ◽  
Large Scale ◽  
Numerical Study ◽  
Small Scale ◽  
Surface Model ◽  
Flame Surface ◽  
Transition Mechanism ◽  
Air Stream ◽  
Scale Fluctuation

A numerical study on the transition from laminar to turbulent of two-dimensional fuel jet flames developed in a co-flowing air stream was made by adopting the flame surface model of infinite chemical reaction rate and unit Lewis number. The time dependent compressible Navier–Stokes equation was solved numerically with the equation for coupling function by using a finite difference method. The temperature-dependence of viscosity and diffusion coefficient were taken into account so as to study effects of increases of these coefficients on the transition. The numerical calculation was done for the case when methane is injected into a co-flowing air stream with variable injection Reynolds number up to 2500. When the Reynolds number was smaller than 1000 the flame, as well as the flow, remained laminar in the calculated domain. As the Reynolds number was increased above this value, a transition point appeared along the flame, downstream of which the flame and flow began to fluctuate. Two kinds of fluctuations were observed, a small scale fluctuation near the jet axis and a large scale fluctuation outside the flame surface, both of the same origin, due to the Kelvin–Helmholtz instability. The radial distributions of density and transport coefficients were found to play dominant roles in this instability, and hence in the transition mechanism. The decreased density in the flame accelerated the instability, while the increase in viscosity had a stabilizing effect. However, the most important effect was the increase in diffusion coefficient. The increase shifted the flame surface, where the large density decrease occurs, outside the shear layer of the jet and produced a thick viscous layer surrounding the jet which effectively suppressed the instability.

Credit—Without Banking—In Early Nineteenth-Century Puerto Rico

1962 ◽  
Vol 19 (2) ◽  
pp. 149-171 ◽  
Author(s):  
Adam Szászdi
Keyword(s):  
Puerto Rico ◽  
The Philippines ◽  
Early Nineteenth Century ◽  
College Professors ◽  
Savings Banks ◽  
Mineral Wealth ◽  
Economic Stagnation ◽  
Financial Expert ◽  
Set Up ◽  
State Of Affairs

The title of this article seems to give the impression that its author is a financial expert. Unhappily, this is not the case. But—for quite unknown reasons—college professors are apt to acquire some empirical knowledge of credit facilities. Besides, I do not intend to give practical advice to anybody. I shall only try to show, how people in Puerto Rico, a century and a half ago, managed to survive—and at times prosper—in the midst of what some people used to call, not very affectionately, the “money complex.”What makes the question interesting is the lack of banks or other credit institutions. Apparently, the first small savings banks did not appear until the 1870's. The paucity, if not the absolute absence, of liquid capital characterizes Puerto Rico until the period under study. Such a state of affairs had remote causes. Puerto Rico, as Spain's second colony in the New World, had had a prosperous start in the sixteenth century. Some gold was found, and the firstingeniowas set up. But in the 1520's an exodus was set off by the attraction of the fabulous mineral wealth of the continent that was being conquered, an exodus that the threat of the death penalty was not able to stop effectively. The lack of sufficient settlers was then the initial cause of Puerto Rico's economic stagnation. Naturally, the following two hundred years should have been more than sufficient to allow recovery, for—popular beliefs to the contrary—mineral wealth was not the only source of economic prosperity in the Spanish monarchy. As a sample, the Philippines exported Chinese goods, Central America cocoa and dyestuff, Venezuela cocoa and tobacco, Guayaquil cocoa and timber, Quito textiles, Peru wine and flour, Chile flour and timber, Tucumán mules, Buenos Aires hides, and Cuba sugar and tobacco.

scholarly journals A new bedrock and surface elevation dataset for modelling the Greenland ice sheet

2003 ◽  
Vol 37 ◽  
pp. 351-356 ◽  
Author(s):  
Jonathan L. Bamber ◽  
Duncan J. Baldwin ◽  
S. Prasad Gogineni
Keyword(s):  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Detailed Comparison ◽  
Radar Data ◽  
The Arctic ◽  
Small Scale ◽  
Surface Model ◽  
Rock Outcrops ◽  
Bed Topography ◽  
Elevation Model

AbstractA new digital elevation model of the surface of the Greenland ice sheet and surrounding rock outcrops has been produced from a comprehensive suite of satellite and airborne remote-sensing and cartographic datasets. The surface model has been regridded to a resolution of 5 km, and combined with a new ice-thickness grid derived from ice-penetrating radar data collected in the 1970s and 1990s. A further dataset, the International Bathymetric Chart of the Arctic Ocean, was used to extend the bed elevations to include the continental shelf. The new bed topography was compared with a previous version used for ice-sheet modelling. Near the margins of the ice sheet and, in particular, in the vicinity of small-scale features associated with outlet glaciers and rapid ice motion, significant differences were noted. This was highlighted by a detailed comparison of the bed topography around the northeast Greenland ice stream.

Numerical Study of Methane and Air Combustion Inside Heat-Recirculating Combustors

2013 ◽  
Author(s):  
Yanxia Li ◽  
Zhongliang Liu ◽  
Yan Wang ◽  
Jiaming Liu
Keyword(s):  
Gas Flow ◽  
Numerical Study ◽  
Convection Heat Transfer ◽  
Central Area ◽  
Small Scale ◽  
Inlet Velocity ◽  
Strong Convection ◽  
Simulation Results ◽  
Lean Fuel ◽  
Set Up

A numerical model on methane/air combustion inside a small Swiss-roll combustor was set up to investigate the flame position of small-scale combustion. The simulation results show that the combustion flame could be maintained in the central area of the combustor only when the speed and equivalence ratio are all within a narrow and specific range. For high inlet velocity, the combustion could be sustained stably even with a very lean fuel and the flame always stayed at the first corner of reactant channel because of the strong convection heat transfer and preheating. For low inlet velocity, small amounts of fuel could combust stably in the central area of the combustor, because heat was appropriately transferred from the gas to the inlet mixture. Whereas, for the low premixed gas flow, only in certain conditions (Φ = 0.8 ～ 1.2 when ν0 = 1.0m/s, Φ = 1.0 when ν0 = 0.5m/s) the small-scale combustion could be maintained.

scholarly journals Accurate age estimation in small-scale societies

2017 ◽  
Vol 114 (31) ◽  
pp. 8205-8210 ◽  
Author(s):  
Yoan Diekmann ◽  
Daniel Smith ◽  
Pascale Gerbault ◽  
Mark Dyble ◽  
Abigail E. Page ◽  
...  
Keyword(s):  
Life History ◽  
Bayesian Approach ◽  
Age Estimation ◽  
Human Life ◽  
The Philippines ◽  
Monte Carlo Algorithm ◽  
Small Scale ◽  
Hunter Gatherers ◽  
Cultural Life ◽  
Ranking Order

Precise estimation of age is essential in evolutionary anthropology, especially to infer population age structures and understand the evolution of human life history diversity. However, in small-scale societies, such as hunter-gatherer populations, time is often not referred to in calendar years, and accurate age estimation remains a challenge. We address this issue by proposing a Bayesian approach that accounts for age uncertainty inherent to fieldwork data. We developed a Gibbs sampling Markov chain Monte Carlo algorithm that produces posterior distributions of ages for each individual, based on a ranking order of individuals from youngest to oldest and age ranges for each individual. We first validate our method on 65 Agta foragers from the Philippines with known ages, and show that our method generates age estimations that are superior to previously published regression-based approaches. We then use data on 587 Agta collected during recent fieldwork to demonstrate how multiple partial age ranks coming from multiple camps of hunter-gatherers can be integrated. Finally, we exemplify how the distributions generated by our method can be used to estimate important demographic parameters in small-scale societies: here, age-specific fertility patterns. Our flexible Bayesian approach will be especially useful to improve cross-cultural life history datasets for small-scale societies for which reliable age records are difficult to acquire.

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