Potensi Limbah Sagu (Metroxylon SP.) Di Kecamatan Tebing Tinggi Barat Kabupaten Kepulauan Meranti Sebagai Substrat Penghasil Biogas

Biogas is one of alternative energy sources that fulfills future fuel needs. This studyaimed to analyse the potency of sago waste as fermentation substrate for biogasproduction. This research was done experimentally by employing sago waste materialsobtained from Sago Factory Nambus River from District West Tebing Tinggi Sub-province Meranti and fresh cow rumen liquid was obtained from slaughterhouse inPekanbaru. The biogas volume was calculated by measuring the volume of water thatwas pushed every 3 days, where the volume of water driven was proportional to thevolume of biogas produced. The bacterial cell numbers was counted using plate countmethod employing Nutrient Agar (NA). The substrate fermentation temperature and pHwere measured every 3 days. The highest biogas volume was produced by fermenter III(45760 ml) containing solid sago waste, liquid sago waste, and rumen liquid with ratio 1: 1 : 1 and the lowest was produced by fermenter II (1600 ml). The total bacterialinvolved in biogas production ranges from 1,87x10 5 – 2,87x10 8 CFU/ml samples. Thetemperature and pH of substrate fermetation was relatively constant during biogasproduction. The results showed that sago waste is potential as substrate for biogasproduction

Risks and benefits of genetically modified foods

There are claims that fear towards new technology has been caused by the lack of information and education on the subject to the public. Modern biotechnology and its applications have been receiving the same criticism. Thus, the objective of this study is to analyze the trends and coverage of genetically modified food (GMF) related issues available in an online database. In order to achieve this, GMFrelated articles (n = 60) were retrieved from a database, Science Direct, from the year 2005 until 2010. These articles were then analyzed using the annotated bibliography and content analysis techniques. It was found that the highest number of articles was in the ’Technical/Progress’ theme with 22 counts followed by the ‘Attitude’ theme with 13 counts. Meanwhile, the ‘Social Risks and/or Benefits’ theme was the lowest with only 1 paper identified. This trend shows that the focus of the majority of papers published were on the progress of GMF technology followed by attitude studies (such as perceptions and willingness to buy) and only a few were discussing the risk and benefit aspects of GMF. These findings are useful in giving us an insight of what have been discussed on GMF in the existing literature.Key words: Genetically modified food (GMF), themes, risks and benefits, content analysis, biotechnology

CONCENTRIC TUBE-FOULING RIG FOR INVESTIGATION OF FOULING DEPOSIT FORMATION FROM PASTEURISER OF VISCOUS FOOD LIQUID

This paper reports the work on developing concentric tube-fouling rig, a new fouling deposit monitoring device. This device can detect and quantify the level of fouling deposit formation. It can also functioning as sampler for fouling deposit study, which can be attached at any food processing equipment. The design is initiated with conceptual design. The rig is designed with inner diameter of 7 cm and with tube length of 37 cm. A spiral insert with 34.5 cm length and with 5.4 cm diameter is fitted inside the tube to ensure the fluid flows around the tube. In this work, the rig is attached to the lab-scale concentric tube-pasteurizer to test its effectiveness and to collect a fouling sample after pasteurization of pink guava puree. Temperature changes are recorded during the pasteurization and the data is used to plot the heat transfer profile. Thickness of the fouling deposit is also measured. The trends for thickness, heat resistance profile and heat transfer profile for concentric tube-fouling rig matched the trends obtained from lab-scale concentric tube-pasteurizer very well. The findings from this work have shown a good potential of this rig however there is a limitation with spiral insert, which is discussed in this paper

Tapered microchannel for multi-particles passive separation based on hydrodynamic resistance

Researches on separation of multi-particles utilizing microfluidic have been flourishing in recent years with the aid from advancements in microfabrication design and technology. Generally, separation is beneficial for biomedical application especially involving heterogeneous samples. Due to inherent problems of samples isolation, a simple and efficient separation device is required. Here, we present a passive tapered microchannel for multi-particles separation using hydrodynamic principle. Our emphasis is on the effect of hydrodynamic resistance coupled with tapered microchannel design. In the experiment, successful multi-particles samples separation was observed. The results were further analyzed and were in agreement with the proposed concept. This method opens the route toward robust, low-cost and high-throughput, thus it may holds potential to be integrated as one functional module in Micro Total Analysis System (µTAS)

Experimental analysis on the effect of cooling surface area and flow rate for water cooled photovoltaic module

Application of water spray or water flow on the surface of photovoltaic (PV) modules is one of the techniques used to increase efficiency. Main parameter that affect the performance by this technique is water flow rate and cooling surface are. However, there is less study focus on those parameters. Thus, the objective of this paper is to investigate the effect of water-cooled surface area and water flow rate on the temperature and power output of the PV. Orifices were used to create half-cooled and fully-cooled surface area for water to flow as cooling techniques while the hand valve was used to control the flow rate of water at 120 L/h, 180 L/h and 240 L/h flowing onto the panel. A solar simulator was constructed and used to provide 600 W/m2, 1,000 W/m2, and 1,200 W/m2 irradiance for the panel. The testing methodology consists of three different experiments for each irradiance level. It was found that more cooling surface area covered could significantly reduce temperature in any irradiance level, and fully-cooled module could keep the temperature at below 40 °C eventhough the irradiance was at 1,200 W/m2. In addition, the optimum flow rate also depends on the cooling surface area. Thus, there is a unique relation between cooling surface area and optimum flow rate. Thus, further investigation is needed on this relation

Exponential Tapered Balun with Different Sizes for UWB Elliptical Dipole Antenna

This work presents a broadband tapered balun with different sizes using nonlinear transition particularly suitable for planar and three-dimensional (3-D) dipole antennas for ultra-wideband (UWB) applications such as communication, radar systems and geolocation precision. Four baluns with wideband microstrip-to-parallel-strip transition using an elliptical structure for an elliptical dipole antenna are proposed. The initial balun structure consists of a nonlinear profile with a quarter-wavelength for both height and width. By studying the current distributions at the balun surface, it can be reduced to 25%, 50% and 75% from the original size. Measured results based on the reflection coefficients for all baluns are shown to be better than -10 dB from 1.0 GHz to 10 GHz. These baluns are integrated with an elliptical dipole which acts as a feeding circuit. Eight set of antennas with a planar and 3-D configurations with four different sizes are proposed in this work. The planar configurations are named as Planar 1, Planar 2, Planar 3 and Planar 4 while the 3-D configurations are named as 3D Dipole 1, 3D Dipole 2, 3D Dipole 3 and 3D Dipole 4, respectively. The results show that all antennas with the proposed baluns operates within the UWB frequency range

Harmonic Suppression Dual-band Dipole Antenna with Parasitic Elements and a Stub

A dual-band harmonic suppression dipole antenna suitable for energy harvesting system is presented in this paper. A linear dipole with two parasitic elements is designed and fabricated with a capability to eliminate the harmonic of higher order modes. At first, the antenna resonates at 900 MHz and 2.7 GHz. Therefore, a parasitic element is added into each of the dipole’s arm to tune the second frequency band to 2.4 GHz to fit into wireless application. However, the presence of two parasitic elements has generated an unwanted harmonic at 4.0 GHz. Thus, a stub has been integrated into the antenna’s terminal (feed line) to suppress the 4.0 GHz frequency. This technique is suitable for developing a multiband antenna with harmonic suppression. The antenna is fabricated on a FR-4 board with the size of 72×152 mm2 which operates efficiently at 0.8 GHz and 2.4 GHz which is suitable for wireless communication applications. The prototype can suppress the undesired harmful harmonics present within the frequency range of 3 to 5 GHz. The antenna has a good potential to be used in a rectenna system with a dual-band frequency operation but with better performance. Simulation and measurement results obtained are in a good agreement, which have confirmed the proposed design concept