•Mode-locking operation at 1075 nm in a DC-YDFL.•A WS2-ZnO deposited on a fiber taper as a saturable absorber.•High power mode-locked dissipative solitons with 3.7 nm 3 dB bandwidth.•Repetition rate ...of 10.98 MHz and Pulse energy of 139.3 nJ.•Higher SA damage threshold due to interaction with evanescent field only.
Efficient and stable mode-locking operation at 1075 nm is demonstrated in a double-clad ytterbium-doped fiber laser (DC-YDFL) with WS2-ZnO deposited on a fiber taper as a saturable absorber (SA). The WS2-ZnO composite is prepared by a simple and cost-effective heating method and deposited onto the fiber taper before being incorporated into the laser cavity. A high power mode-locked normal dispersion output at 1075 nm with a 3 dB bandwidth, repetition rate, pulse width and pulse energy of 3.7 nm, 10.98 MHz, 459 fs and 139.3 nJ respectively are obtained at a pump power of 3.65 W. Due to the interaction of the WS2-ZnO nanoparticles with the evanescent field of the propagating signal instead of directly, the SA has a higher laser damage threshold, therefore allowing for higher pulse powers to be obtained.
Starch is the main component that consumed one third in the human diet. One-third of starch produced in the world is used in non-food application such as rubbers production and plastic. Plastic ...produced from starch which called as bio-plastic is biodegradable and helps in reducing the world pollution which non-degradable plastic now endanger the ecosystem either land or water. Microalgal the easy growing and environmental friendly have opened new potential of revolution for starch-based bio-plastic. The small granules of starch produced from microalgae possess an advantage to replace the starch from food-based, as the small granules able to yield a good quality of bio-plastic. In this study, marine microalgae had been studied for its starch content and could reach up to 19% of total starch content. However, in order to ensure the starch produced from marine microalgae is suitable for bio-plastic application, the characteristics of starch had been studied based on the size of starch granules, amylose/amylopectine content, swelling power and solubility and turbidity. These analyses were done with a comparison of corn starch that used widely in the production of bio-plastic. Hence, by determining these crucial characteristics, the application of starch from microalgae could be expended to various sustainable products.
Colorimeter is a detector that is used to determine the concentration by analyzing the intensity of light transmitted by the solution. The samples used in this study are harmful and harmless dyes. ...The light emitted will pass through the sample, so that the beam of light in the sample will be captured by the photodiode sensor. The photodiode sensor functions to convert light into an output voltage. The output voltage will be amplified by a voltage amplifier circuit. The results of the output voltage are confirmed on the arduino which is then displayed on the LCD. In this paper, we will explain the performance of color detector devices that have been developed and their implications for the field of medicine and food.
This paper aims to provide a description of the implementation of Physic Problem Solving strategy combined with concept maps in General Physics learning at Department of Physics, Universitas Negeri ...Padang. Action research has been conducted in two cycles where each end of the cycle is reflected and improved for the next cycle. Implementation of Physics Problem Solving strategy combined with concept map can increase student activity in solving general physics problem with an average increase of 15% and can improve student learning outcomes from 42,7 in the cycle I become 62,7 in cycle II in general physics at the Universitas Negeri Padang. In the future, the implementation of Physic Problem Solving strategy combined with concept maps will need to be considered in Physics courses.
Environmental sustainability through end-of-life recovery has become the main items of contest in the automotive industries. Component reuse as one of the product recovery strategy is now gaining ...importance in view of its impact on the environment. Disassembly as one of the determinant factors for reuse is a very important and difficult process in life cycle engineering. To enable reuse, a certain level of disassembly of each component is necessary so that parts of the products that have arrived at their end-of life can be easily taken apart. Improvements to the disassembly process of products can be achieved at two levels: in the design phase, making choices that favours the ease of disassembly of the constructional system (design for disassembly) and planning at best and optimising the disassembly sequence (disassembly sequence planning). Hence, finding an optimal disassembly sequence is important to increase the reusability of the product. This paper presents the development work on an optimisation model for disassembly sequence using the genetic algorithms (GA) approach. GA is chosen to solve this optimisation model due to its capability in solving many large and complex optimisation problems compared with other heuristic methods. The fitness function of the GA in this study is dependent on the increment in disassembly time. Comparison of results using different combinatorial operators and tests with different probability factors are shown. This paper will present and discuss the disassembly sequence of an engine block, as a case example which achieves the minimum disassembly time.
A new code structure for spectral-amplitude-coding optical code-division multiple-access system based on double-weight (DW) code families is proposed. The DW code has a fixed weight of two. By using ...a mapping technique, codes that have a larger number of weights can be developed. Modified double-weight (MDW) code is a DW code family variation that has variable weights of greater than two. The newly proposed code possesses ideal cross-correlation properties and exists for every natural number n. Based on theoretical analysis and simulation, MDW code is shown here to provide a much better performance compared to Hadamard and modified frequency-hopping codes.
Abstract
Poor subgrade soil conditions might cause insufficient pavement support and shorten the life of the pavement. The addition of chemical or cementation additives to subgrade soils can help ...pavement to perform better. Chemical additives can be anything from waste to manufactured components like lime and coconut shell ash (CSA). These additives can be used to improve the qualities of a of soils. The efficiency of these additives is determined by the type of soil treated and the amount of additive used. Therefore, this research investigated the properties of expansive clay soil when stabilized by lime and CSA. The physical properties tests were carried out on the natural soil sample for identification and classification; and later, the mechanical properties tests were performed on the soil sample namely California Bearing Ratio (CBR). All the tests were performed in accordance to BS 1377 (1990). The soil sample was added with lime in a constant quantity of 6%, while CSA was added in proportions of 2%, 4%, 6%, and 8% from the total weigh of admixed sample. The constant lime percentage of 6% was used for stabilization as it recorded the highest CBR value during testing. The highest percentage of lime-CSA mixture was achieved at Variation 2 (6% lime + 4% CSA) for 4, 7, and 28 days as the highest value of soaked CBR was observed at this stage. Thus, it is proven that treating expansive soil with CSA combined with lime enhances it strength.
Malaysia is aiming to increase its renewable energy generation capacity from 2% to 20% by 2030. Solar photovoltaic (PV) system will play a huge role in getting this target achieve as it is considered ...a maturing technology in Malaysia and the nation is blessed with ample amount of solar irradiation throughout the year. However, in Malaysia, this technology faces various implementation challenges such as the PV performance degradation due to dust deposition on the PV panels. Generally, coal-fired power plants have an abundant area of coal ash pond that is suitable for installing floating PV systems. However, this area is prone to dust deposition resulting from pulverized coal particles and fly ashes. This paper aims to evaluate the effects of dust deposition on PV panels' performance, specifically for PV systems that will be installed near coal-fired power plants in Malaysia. In this study, PV panels were exposed to four different types of dust deposit conditions, which are coal particles, fly ashes, normal environmental dust as well as control PV panel that was clean on daily basis. The tests were carried out outdoor under natural sunlight. Performance of the PV panels were measured based on the power generated by the panels. The average power drop based on the types of dust deposition on PV panels are; natural dust (2.72%), fly ash (13.16 %) and coal ash (15.82 %).
PDF
