5,483 research outputs found
Design analysis of potential grid connected floating photovoltaic system in UTHM
Every month Universiti Tun Hussein Onn (UTHM) management pays around RM 1 million for electricity bills. The aim of this project is to explore the feasibility of implementing a grid connected Floating Photovoltaic (FPV) system at the campus of UTHM. There are multiple unutilized water bodies (ponds/lakes) within the campus premises covering a total area of more than 50,000 m2. A 4000 m2 located at the lake near faculty of technical and vocational education (FPTV) is considered of the total available area for the feasibility study. A total of 1372.6 kW can be generated by deploying 335W mono crystalline PV modules with 21% efficiency on a floating mechanism (floaters) on the selected area. The FPV system is then simulated using MATLAB Simulink to observe the performance parameters of the FPV system such as total harmonic distortion (THD), current and voltage waveforms. Hybrid Optimization Model for Electric Renewable (HOMER) software has been used to obtain results such as the net present cost (NPC), cost of operation (COE), CO2 emissions impact and the payback period of the grid connected FPV system. The FPV system provides the lowest cost of energy (LCOE) RM0.418 kWh and a total net present cost (NPC) of RM 52.3 million. This system can decrease CO2 emissions by about 1241 t/yr
Mechanical and physical properties of fly ash foamed concrete
Foamed concrete has become most commercial material in construction industry. Fly
ash is receiving more attention now since their uses generally improve the properties
of blended cement concrete, cost saving and reduction of negative environmental
affects. The physical and mechanical properties of foamed concrete differ according
to a different type of mixture and its composition. Therefore, this research
investigates physical and mechanical properties of fly ash foamed concrete. Fly ash
was used as fine aggregate. Six series of fly ash foamed concrete for target densities
(1000, 1100,1200,1300,1400 and 1500 kg/m
) with constant cement to fly ash ratio
(1:1.5) and cement to water ratio (1:0.65) by weight were prepared and tested. Tests
were conducted to study physical properties (work ability, water absorption, drying
shrinkage and carbonation) and mechanical strengths properties (compressive,
splitting tensile and flexural strengths). Three types of specimens (cube, cylinder and
prism) were used in different quantity and different purposes. The specimens of
drying shrinkage test were opened after one day but, others specimens were demoulded
after
three
days
and
subjected
to air
curing
under
room
temperature.
As
result,
the findings
from
this
project
are
very
encouraging
towards
the
use
of
fly
ash
foamed
concrete
density
of
1100 and
1200 kg/m
3
in block application due to its
compressive strength (3.7 – 6.7 MPa) whereas density of 1300, 1400 and 1500 kg/m
3
3
in structural application due to its high compressive strength (10 – 18.8 MPa) and
moderate water absorption that was below 10%. It was also found that the physical
properties of fly ash foamed concrete are high drying shrinkage between -666 to 1022
micro
strain,
high
water
absorption
for
density
less than 1300
kg/m
, higher
workability (115 -180 mm diameter) and high carbonation depth that make it a good
breathable material that removes carbon dioxide from our environment. Lastly
comparative analyses were done to determine the relationships between the various
mechanical properties parameters of the fly ash foamed concrete, namely the
compressive strength, flexural strength, splitting tensile strength and mathematical
equations were derived
Effect of nitrogen fertilization on morphological and biochemical traits of some Apiaceae crops under arid region conditions in Egypt
Khalid KA. 2013. Effect of nitrogen fertilization on morphological and biochemical traits of some Apiaceae crops under arid region conditions in Egypt. Nusantara Bioscience 5: 15-20. Arid regions in Egypt are characterized by poor nutrients content and unfavorable environmental conditions which negatively affect growth and productivity of medicinal and aromatic plants including anise, coriander and sweet fennel. So the main objective of the present investigation was to study the effect of different levels of N, namely 0 (control), 100, 150 and 200 kg ha-1 used as ammonium sulphate [(NH4)2SO4] (20% N), on selected morphological and biochemical characteristics of anise, coriander and sweet fennel plants cultivated under arid regions conditions during two successive seasons. The most effective dose of nitrogen was 200 kg ha-1 of N, resulting in a positive increase in vegetative growth characters and content of essential oil, fixed oil, total carbohydrates, soluble sugars, protein and nutrients (NPK)
Testing Semi-strong Form Efficiency of Stock Market
The efficient market hypothesis suggests that stock markets are “informationally efficient”. That is, any new information relevant to the market is spontaneously reflected in the stock prices. A consequence of this hypothesis is that past prices cannot have any predictive power for future prices once the current prices have been used as an explanatory variable. In other words the change in future prices depends only on arrival of new information that was unpredictable today hence it is based on surprise information. Another consequence of this hypothesis is that arbitrage opportunities are wiped out instantaneously. Empirical tests of the efficient market hypothesis actually test for these consequences in various ways. Some of them have been summarised in earlier chapters. These tests generally could not conclusively accept the random-walk hypothesis of stock returns even when GARCH effects were accounted for. Many studies have found empirical regularities that are contrary to the efficient market hypothesis. For example, the monthly, weekly and daily returns on stocks tend to exhibit discernable patterns, such as seasonal affects, month of the year affect, day of the week affect, hourly affect etc. In case of Pakistan’s stock markets too such affects are identified. Such as the Ramadan affect [see Hussain and Uppal (1999)], seasonal effects and day of the week affect. Further, the wide spread use of “technical analysis” among stock traders and their ability to predict to some extent the direction of movements in the prices of individual stocks over medium term testifies to the existence of patterns and seasonal trends.
THE RELATIONSHIP BETWEEN PROLACTIN LEVEL AND THE DURATION OF LACTATIONAL AMENORRHOEA IN LACTATING SUDANESE WOMEN
Background: This study aimed to assess the relationship between the prolactin (PRL) level and the duration of lactational amenorrhoea in lactating Sudanese women.
Methods: Sudanese women (135) from Omdurman area with different ages (18-41 years) and stages of lactation were included, 61 of them participated by giving venous blood samples and filling a questionnaire, while the others by filling the questionnaire only. Pregnant women, contraceptives users, and hypothyroid patients were excluded. The subjects were divided into lactational amenorrhoeic (Group I), and lactating menstruating subjects (Group II). Then each group was subdivided according to the duration of lactation into: -
Lactating for six months or less.
Lactating for more than six months.
Prolactin level was measured using radioimmunoassay (RIA).
Results: In this study the mean prolactin level in-group I (2934.99 mU/L) was significantly higher compared with group II (707.46 mU/L) (P<0.05).
For the duration of lactation, PRL level in the first six months was higher (4414 mU/L), (1506.60 mU/L) in group I, and group II respectively, while this level decreased after six months (1538 mU/L), (517.19 mU/L) for the two groups.
Also we found that factors like breast-feeding patterns, utilization of supplementary foods, and the number of parities had a significant effect on the duration of lactational amenorrhoea.
Conclusions: There was a positive relationship between PRL level and the duration of lactational amenorrhoea (r=0.39)
A simplified dynamic systems approach for the energy rating of dwellings
The drive to reduce carbon emissions and energy utilisation, directly associated with dwellings and to achieve a zero carbon home, suggests that the assessment of energy ratings will have an increasingly prioritised role in the built environment. Created by the Building Research Establishment (BRE), the Standard Assessment Procedure (SAP) is the UK Government’s recommended method of assessing the energy ratings of dwellings. This paper describes a new, simplified dynamic method (hence known as IDEAS – Inverse Dynamics based Energy Analysis and Simulation) of assessing the controllability of a building and its servicing systems. The IDEAS method produces SAP Comparable results. Results suggest this design approach could enhance the SAP Methodology by the addition of advanced systems controllability and dynamic values
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