Experimental demonstration of cap transmitter using very high speed IC hardware description language (VHDL)

Carrierless Amplitude Phase (CAP) Modulation is a multidimensional and multilevel of modulation scheme which it is strongly inspired by QAM modulation scheme. CAP does not depend on a carrier and it is much simpler. Lots of CAP modulation experiments have been proposed and demonstrate but none of them were introduced in real time system. Therefore Very High Speed IC Hardware Description Language (VHDL) has been chosen as a method to investigate the modulation of CAP transmitter in real time. This project focused on 2D CAP transmitter implementation in VHDL. The aim of this project is to investigate the CAP transmitter modulation by using Fast Fourier Transform (FFT) and implement the core signal processing blocks using VHDL. Therefore 4 selected blocks of CAP transmitter: random generator, constellation mapper, modulation and Inverse Fast Fourier Transform (IFFT) were designed and analyzed. Then they were compared to the theory of CAP modulation and Quadrature Amplitude Modulation (QAM).The transition table was created based on modulation theory for proofing purposed. Quartus II has been used for simulation in implementing 4 RAMs, 1 radix butterfly and designing an IFFT. 3 stages were connected with each other using CORDIC algorithm and 23 multiplexers. We believe that this project is a good start for implementing 2D-CAP in the real time. Real time is good because it is timeliness, fast, low loss rate, low end to end delay and very cost effectively

Optimization of oxygen transfer through venturi-based systems applied to the biological sweetening of biogas

Peer ReviewedPostprint (published version

Bio-Processes of the Oxidation Ditch When Subjected to a Sub-Arctic Climate

Alaska's far northern area is sparsely populated primarily because of a severe climate which varies from northern temperate to Arctic. Construction and power costs are high. Skilled operating personnel are scarce and expensive, if available. Receiving streams are said to be delicate, particularily in the winter, when little possibility for reaeration exists due to a total ice cover. The oxidation ditch modification of the extended aeration activated sludge process appears to be well suited for the treatment of wastes in this environment. Past operating data on a plant of this type located in Interior Alaska (near Fairbanks) indicated it may be well suited to treat small volumes of domestic waste economically, with low sludge production, and minimal sensitivity to low temperatures.The work reported on herein was done under Contract No. RFP DACA 897l- R-0006 from the U. S. Army Cold Regions Research and Engineering Laboratory, Hanover, New Hampshire

Forecasting wind speed data by using a combination of ARIMA model with single exponential smoothing

Wind serves as natural resources as the solution to minimize global warming and has been commonly used to produce electricity. Because of their uncontrollable wind characteristics, wind speed forecasting is considered one of the best challenges in developing power generation. The Autoregressive Integrated Moving Average (ARIMA), Simple Exponential Smoothing (SES) and a hybrid model combination of ARIMA and SES will be used in this study to predict the wind speed. The mean absolute percentage error (MAPE) and the root mean square error (RMSE) are used as measurement of efficiency. The hybrid model provides a positive outcome for predicting wind speed compare to the single model of ARIMA and SES

A new combined approach to improved lipid production using a strictly aerobic and oleaginous yeast

Microbial lipids have potential applications in energy, and food industry, because most of those lipids are triacylglycerol with long-chain fatty-acids that are comparable to conventional vegetable oils and can be obtained without arable land requirement. Rhodosporidium toruloides is a strictly aerobic strain, where oxygen plays a crucial role in growth, maintenance, and metabolite production, such as lipids and carotenoids. Dissolved oxygen concentration is one of the major factors affecting yeast physiological and biochemical characteristics. In this context, different approaches have been developed to increase available oxygen by the increasing the aeration and the addition of an oxygen-vector. The growth of R. toruloides in 2-L mechanical stirred tank reactor equipped with 1 or 2 porous spargers and a 70 C/N ratio, revealed a lipid content of 0.47 and 0.52 g/g and a lipidic productivity of 0.16 and 0.17 g/L day, respectively. The oxygen-vector addition, increased the lipidic productivity for 0.20 g/L day and a lipid contend of 0.51 g of lipids/g of biomass. The combined approach, combining high aeration (AA), and 1% of n-dodecane addition (DA), produced a significant improvement in the lipid accumulation (62%, w/w), when compared with the DA (51%, w/w) and the AA (52%, w/w) approaches. The increasing of lipids accumulation and smaller culture time are key factors for the success of scale-up and profitability of a bioprocess.info:eu-repo/semantics/publishedVersio

Application of NASA-developed technology to the automatic control of municipal sewage treatment plants

A search was made of NASA developed technology and commercial technology for process control sensors and instrumentation which would be applicable to the operation of municipal sewage treatment plants. Several notable items were found from which process control concepts were formulated that incorporated these items into systems to automatically operate municipal sewage treatment plants. A preliminary design of the most promising concept was developed into a process control scheme for an activated sludge treatment plant. This design included process control mechanisms for maintaining constant food to sludge mass (F/M) ratio, and for such unit processes as primary sedimentation, sludge wastage, and underflow control from the final clarifier

Influence of temperature on the performance of a full-scale activated sludge process operated at varying solids retention times whilst treating municipal sewage

In this study, the solid retention time (SRT) was varied with the ambient temperature for a full-scale municipal activated sludge plant with capacity of 200,000 PE (Population Equivalent) located in a humid sub-tropical environment. The effects of ambient temperature on treatment performance were investigated. Off-line samples were collected and analyzed from the treatment plant. The actual temperature variation during the study period was divided into three overlapping ranges and the SRT was adjusted accordingly with temperature in order to achieve the desired effluent quality. The plant’s observed effluent quality and thereby its overall removal efficiency was evaluated in terms of measuring standard biochemical parameters. The results indicate that significant improvement in effluent quality can be obtained by applying the variable SRT (5–7 days) dependent on temperature variation

The Design of Automated Control System for Wastewater Treatment Plant

Currently, because of the daily human waste to environment, the water, the air breathed by humans are not clean. Even though most developed countries are having improved system of wastewater treatment system, the treatment process is done partly by human and sometimes problem can occur during the process which reduces the quality of the effluent wastewater. In order to overcome human errors, the use of digital computer to control the process of the wastewater treatment processes is needed. This report discusses about the process of wastewater treatment process and how to design the automated control system for the system. Domestic wastewater can be treated in many ways: physical, chemical and biological unit processes. Since the wastewater treatment process is vast and at the same time, the most important process in wastewater treatment, activated sludge process, will be discussed. Automated control system design for the plant is also built using activated sludge wastewater treatment proces

A study of the effect of substrate composition on the microbial ecology of activated sludge

Eighty percent of all biologically treated waste waters in Europe are oxidised by the activated sludge process. Bulking sludge caused by the proliferation of filamentous organisms is the primary cause of failure of this system. The effect of various substrates in both laboratory scale, fully mixed and sequencing batch (SBR) reactor configurations were used to assess their combined effect on activated sludge microbial ecology and hence sludge settlement. Five different substrate types were used ; synthetic sewage, a basic monosaccharide, disaccharides, polysaccharides and amino acids. In all cases using the fully mixed reactor, bulking occurred while, good settling sludge was produced in the sequencing batch reactor. The cause of this bulking was deemed to be due to the lack of so called "selector effect" within the fully mixed reactor characterised by :- i) high rates of substrate consumption ii) high oxygen (or generally: electron acceptor) up take rate iii) enhanced growth of zoogleal bacteria iv) increased metabolic diversity This laboratory work was compared and contrasted with a pure oxygen activated sludge (VITOX) system treating a high strength pea processing waste water. This fully mixed system had proved difficult to operate since its installation and in the first two years of this study suffered bulking caused by low dissolved oxygen levels. In the third year a combination of a hydraulic problem and subsequent lack of control led to filamentous bulking. This particular bulking incident was controlled by the addition of chlorine to the aeration tank which was selectively toxic to the filamentous organisms present. Due to the studies carried out at both laboratory and full scale an initial contact zone was installed within the main aeration tank prior to the 4th year of this study so as to create an area of high floc loading and high substrate uptake. This initial anoxic contact zone proved successful in preventing the development of a poorly settling sludge and is in line with common practice for the elimination of filamentous bulking reported in the literature. Oxidation Reduction Potential (ORP) proved a reliable and appropriate monitor of conditions of low to zero D.O. experienced in the laboratory scale reactors and at full scale in the anoxic contact zone. It was also found that ORP could be used to detect when D.O. levels became completely depleted and monitor reductions in nitrate levels