A+ A A-

Automatic Cooling System Using PIC 18F4550 For Solar Panel

 


Automatic Cooling System Using PIC 18F4550 For Solar Panel
 

 

 

 

 

Solar photovoltaic (PV) power generation is an attractive technique to reduce consumption of fossil fuels and as a renewable energy. The temperature of PV panel increases when it absorbs solar radiation, causing a decrease in efficiency. The power and efficiency of PV panel usually falls at the rate of ~0.5 %/˚C and ~0.05 %/˚C respectively as increase of ambient temperature. To actively cool the PV panel, an automatic solar cooling system is design by using DC brushless fan and DC water pump with inlet/outlet manifold. This system is needed for uniform airflow and water flow distribution at the back and front surface of PV panel. Temperature sensors were installed on the PV panel to detect temperature of PV. PIC 18F4550 was used to control the operation of DC brushless fan and water pump depending on temperature PV panel. This controller system is an intelligent system because it will run the DC hybrid cooling system when the temperature of PV panel reaches setting level that detected by temperature sensors automatically and avoid waste electrical energy.

The maximum voltage output, maximum current output and maximum power output and every change temperature on PV panel were shown to compare the performance with and without cooling system. The results showed that the PV panel with cooling system is higher in term of power output compare to without cooling system. The higher efficiency of PV panel, the payback period of the system can be shorted and the lifespan of PV panel can also be longer.

Keywords:PV panel, DC hybrid cooling system, PIC controller, Temperature, Power Output

Mitigating Interference in a Heterogeneous Wireless Network using Channel Selection


Mitigating Interference in a Heterogeneous Wireless Network using Channel Selection

 

 

 


 

 

 

 

 

 


 
With the extensive development of heterogeneous wireless communication technology, combined with the advances of data acquisition, emerges a new trend of networked acquisition systems. Among this range of wireless technology, Wireless Sensor Networks (WSNs) has attracted much interest and visibility due to its huge application space. One challenge using the WSN is the short range of the sensor nodes that increases the complexity of transporting the data to a central server. The integration with Wireless Mesh Networks (WMNs) expands the communication range and allows mobility of the device. Thus, WSN can be used for forming the underlying sensing and WMN supports the network infrastructure in pervasive computing environments. However, interference is a problem as these networks share the same 2.4GHz industrial, scientific and medical (ISM) unlicensed band. The impact of the interference on the IEEE 802.11g (WMN) using OFDM modulation and on IEEE 802.15.4 (WSN) using DSSS is investigated in this research. Results from a series of experiments on the AIT wireless mesh campus network under realistic load conditions are presented. Packet retransmission and packets drop rate were measured and based on this knowledge, a channel interference classification (CIC) method is presented to identify the interfering operating channel. The method introduced is based on a technique proposed by Chowdhury et. al. for channel selection based on reference power values. This work modifies the technique to account for differences on channel spectrum characteristic found in tests on the Mesh Campus Network. A channel selection algorithm was then developed for WSN to decide on the operating transmission channel that is not under interference, hence reducing packet losses in the network. This paper will be of interest to network operators and organisations where critical information retrieval over wide area networks is required.

Keywords: Wireless sensor networks (WSNs), IEEE 802.15.4, channel interference, wireless network coexistence.

Polymer Nanocomposites for Piping Application

 


Polymer Nanocomposites for Piping Application
 

 



 

 

 

 

 



Epoxy based nanocomposites incorporating nanoclay and several types of geopolymer raw materials obtained from Saudi Arabia were explored for piping application. The flexural and compressive properties and performance were studied from several series of epoxy nanocomposites containing different ratio of epoxy/hardener, and nanoclay/geopolymer. In addition, different kinds of geopolymer raw materials such as fly ash, kaolin, pozzolonic, silica sand and white clay were employed as filler. The effect of different combination and ratio of these materials on the mechanical properties and morphology of the resulted nanocomposites were investigated. Preliminary studies showed promising properties of these nanocomposites for further development in pipe application.

Keywords:Polymer, Nanocomposite, Nanoclay, Geopolymer, Pipe, compressive strength, flexural strength, flexural modulus.

Studies of Geopolymerization Route For Metakaolin Geopolymeric Materials


Studies of Geopolymerization Route For Metakaolin Geopolymeric Materials

 

 

 


 

 

 

 

 

 


 
Investigation on production of metakaolin geopolymeric powder was aimed to increase the productivity and application of geopolymer products. Geopolymerization process was applied in the manufacturing of metakaolin geopolymeric powder to be used in geopolymer synthesis. Geopolymer slurry was made by alkaline activation of metakaolin in alkali activator solution (a mixture of NaOH and sodium silicate solutions). The geopolymer slurry was heated in an oven to produce pre-cured paste and then pulverized to get uniform particle size geopolymeric powder. By adopting the concept of “just add water”, the metakaolin geopolymeric powder was mixed with water and then oven-cured to produce resulting geopolymer pastes. The results showed that the optimum conditions for producing highest strength resulting paste are by using 8M of NaOH solution, solids/liquid ratio of 0.80, an activator ratio of 0.20, pre-curing of 80°C for 4 hours, 22% of mixing water and curing regime of 60°C for 72 hours. The resulting geopolymer pastes have low bulk density and were potential for a lightweight material. Upon the mixing of water with geopolymeric powder, densification of the structure occurred with the formation of compact geopolymer gels. The geopolymeric powder and resulting pastes showed the combination of amorphous and crystalline phases as analyzed by XRD. After ageing, the intensities of zeolites crystalline phases increased and this emphasized the benefit of zeolites in strength development of resulting pastes. This study clearly demonstrates that the production of metakaolin geopolymeric powder was able to be used in manufacturing geopolymer pastes.

Keywords: Geopolymer, powder, activator solution, geopolymerization, water

Advanced Anaerobic Suspended Growth Closed Bioreactor (ASGCB) for the Production of Biomethane Gas

 

 

Advanced Anaerobic Suspended Growth Closed Bioreactor (ASGCB) for the Production of Biomethane Gas
 


 

 

The Anaerobic Suspended Growth Closed Bioreactor (ASGCB) was developed to generate bio-methane gas from the palm oil wastewater. The ASGCB offers high potential for rapid disintegration of organic matter to produce bio-methane gas that can be used to generate electricity. A significant amount of bio-methane gas is produced from the ASGCB for the treatment of palm oil wastewater. The ASGCB provides pilot scaled proved operational control in order to achieve optimal performance. Pilot scaled proved that the value of methane yield at 0.45 L CH4/ g CODreduction and 0.34 L CH4/ g CODreduction for thermophilic and mesophilic ASGCB are so far the highest methane yield for palm oil wastewater.
The COD reduction efficiency of the thermophilic and mesophilic ASGCB was in the range of 90.90% - 83.58% and 89.66% - 79.83%, respectively, between the HRT 8 days and 24 days. The pH for both ASGCB were in the range of 8.05 to 7.74 and 7.80 to 7.35. High amounts of biogas were produced from 19.86 L biogas/day to 64.56  L biogas/day and 17.79 L biogas/day to 46.76  L biogas/day, respectively. The daily methane gas production were from 14.92 L CH4/day to 44.54 L CH4/day and from 12.92 L CH4/day to 30.81 L CH4/day, respectively, in the thermophilic and mesophilic ASGCB. The methane gas content ranged from 75.11 % to 68.99 % and 72.50 % to 65.90 % for both ASGCB.

Keywords: Anaerobic Degradation Process, Palm Oil Mill Effluent, Biogas Production, Methane Gas, Renewable Energy, Volatile Fatty Acids, 16S rDNA Bacterial Identification.

Surface Functionalization of Carbon-Based Transistor For Aptamer Immobilization In Protein Sensor Application

 


Surface Functionalization Of Carbon-Based Transistor For Aptamer Immobilization In Protein Sensor Application
 

 

 

 

 

 


Carbon-based material including carbon nanotubes (CNTs), diamond and graphene are central materials in nanoscience. Their unique electrical, physical, mechanical and chemical properties are widely studied so as to develop biosensor devices. The current trend of biosensing is moving towards the realization of point-of-care diagnostic systems, which involve the integration of all the analytical stages on a single chip. In this study, a combination of aptamer modified multiwalled carbon nanotube integrated with field effect transistor (MWCNT-FET) were demonstrated for human immunodeficiency virus-1 (HIV-1) Tat protein detection. The effect of surface functionalization of multiwalled carbon nanotube (MWCNT) is investigated by introducing carboxyl functional group through chemical surface treatment.

The functional group on CNTs surface were characterized by using Fourier transform infra red (FTIR), Scanning electron microscope (SEM), Thermo gravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS). RNA aptamer were immobilized on the CNT functionalized surface by covalent binding. Aptamer act as molecular recognition element for HIV-1 Tat protein. The current-voltage measurements were studied before and after aptamer immobilization. A series of analyte concentration were measured to determine the limit of detection for CNTs-FET biosensor. The specificity of the aptamer probe and the stability of the device detection has been investigated. The device will be validate on the usage of the real sample from human bodily fluid to evaluate the effectiveness of detection. The performance of the biosensor were demonstrated not only by current-voltage measurement but also cyclic voltammetry. There were also supporting test on colorimetric study conducted to confirmed the reaction between the aptamer and protein.

Keywords: MWCNT, RNA Aptamer, HIV-1 Tat Protein, Surface Functionalization.