scholarly journals Kinetic Parameter Estimation and Mathematical Modelling of Lipase Catalysed Biodiesel Synthesis in a Microreactor

Micromachines ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 759 ◽  
Author(s):  
Gojun ◽  
Pustahija ◽  
Jurinjak Tušek ◽  
Šalić ◽  
Valinger ◽  
...  
Keyword(s):  
Residence Time ◽  
Batch Reactor ◽  
Methyl Esters ◽  
Thermomyces Lanuginosus ◽  
New Approach ◽  
Kinetic Parameter Estimation ◽  
Proposed Model ◽  
Biodiesel Synthesis ◽  
Independent Experimental Data ◽  
Science Production

Development of green, clean, and sustainable processes presents new challenges in today’s science. Production of fuel is no exception. Considering the utilisation of various renewable sources, the synthesis of biodiesel, characterised as more environmentally-friendly then fossil fuel, has drawn significant attention. Even though the process based on chemical transesterification in a batch reactor still presents the most used method for its production, enzyme catalysed synthesis of biodiesel in a microreactor could be a new approach for going green. In this research, edible sunflower oil and methanol were used as substrates and lipase from Thermomyces lanuginosus (Lipolase L100) was used as catalyst for biodiesel synthesis. Experiments were performed in a polytetrafluoroethylene (PTFE) microreactor with three inlets and in glass microreactors with two and three inlets. For a residence time of 32 min, the fatty acids methyl esters (FAME) yield was 30% higher than the yield obtained for the glass microreactor with three inlets. In comparison, when the reaction was performed in a batch reactor (V = 500 mL), the same FAME yield was achieved after 1.5 h. In order to enhance the productivity of the process, we used proposed reaction kinetics, estimated kinetic parameters, and a mathematical model we developed. After validation using independent experimental data, a proposed model was used for process optimization in order to obtain the highest FAME yield for the shortest residence time.

scholarly journals Transesterification in Microreactors—Overstepping Obstacles and Shifting Towards Biodiesel Production on a Microscale

Micromachines ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 457 ◽  
Author(s):  
Martin Gojun ◽  
Matea Bačić ◽  
Anabela Ljubić ◽  
Anita Šalić ◽  
Bruno Zelić
Keyword(s):  
Production Process ◽  
Reaction Path ◽  
Batch Reactor ◽  
Enzymatic Reaction ◽  
Deep Eutectic Solvents ◽  
Biodiesel Production ◽  
Thermomyces Lanuginosus ◽  
Process Equipment ◽  
Enzymatic Transesterification ◽  
Biodiesel Synthesis

Biodiesel, which was earlier used only as an alternative fuel, is now an indispensable component of commercial diesel. Conventional production processes are unable to cope with the increasing demand for biodiesel, and therefore more and more work is being done to intensify the existing processes. The intensification of the biodiesel production process, taking into account the environmental and economic factors, is based on increasing productivity. One way to achieve that is by reducing the volume of production units. The application of the enzymatic reaction path, while reducing the volume of process equipment to the micro-level, has significantly magnified the productivity of the biodiesel production process, which is primarily due to better mass transfer in microsystems. Additional breakthrough is the use of deep eutectic solvents (DES) instead of buffers for enzyme stabilization. In this study, a lipase from Thermomyces lanuginosus (TlL) (both commercial and produced by solid-state fermentation) was used as a catalyst for biodiesel production. Edible and waste sunflower oil, as well as methanol, were used as substrates. The reaction mediums were buffer and DES. The transesterification reaction was carried out in a batch reactor and the emphasis was made on different microreactor configurations. The highest yield of 32% for residence time of only τ = 30 min was obtained in the microreactor system with an emulsion of waste oil and a commercial enzyme suspended in a buffer. This indicates that enzymatic transesterification could be a valuable reaction path for dealing with waste oils. Furthermore, biodiesel synthesis in DES showed somewhat lower yields, but by increasing the water content in the system, the reaction could prove much better results. In the end, the effects of reaction conditions on the volumetric productivity of the process were analyzed.

scholarly journals Noncatalytic biodiesel synthesis from rubber seed oil via supercritical methanol and ethanol

2016 ◽  
Vol 19 (3) ◽  
pp. 129-137
Author(s):  
Viet Tan Tran ◽  
Phung Thi Kim Le ◽  
Anh Tuan Pham ◽  
Khoa Anh Tran
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Methyl Esters ◽  
Seed Oil ◽  
Batch Reactor ◽  
Methyl Esters ◽  
Ethyl Esters ◽  
Supercritical Methanol ◽  
Rubber Seed Oil ◽  
Rubber Seed ◽  
Biodiesel Synthesis

This paper reports the production of fatty acid methyl esters (FAMEs) and fatty acid ethyl esters (FAEEs) by the transesterification reaction of rubber seed oil (RSO) in supercritical methanol and ethanol without using any catalyst. Experiment were carried out in a batch reactor, and reactions were studied at 260, 280, 300 and 320 oC at a pressure of 8.1-19 MPa with various mole ratios of ethanol – to - methanol from 0 to 100%. The extent of the reaction was explored using a convertibility parameter, which corresponds to the maximum ester content attainable from the feedstock. The highest FAME and FAEE contents achieved were 91.8 % and 86.4%, respectively. Results show that transesterification of RSO in methanol was more efficient than that in ethanol; the temperature had the strongest influence.

Intelligent recognition of semantic relationships based on antonymy

2020 ◽  
Vol 16 (3) ◽  
pp. 263-290
Author(s):  
Hui Guan ◽  
Chengzhen Jia ◽  
Hongji Yang
Keyword(s):  
Semantic Similarity ◽  
New Approach ◽  
Word Similarity ◽  
Semantic Relationships ◽  
Proposed Model ◽  
Path Distance ◽  
The Hierarchical Structure ◽  
Thinking Process ◽  
Similarity Measuring ◽  
Intelligent Recognition

Since computing semantic similarity tends to simulate the thinking process of humans, semantic dissimilarity must play a part in this process. In this paper, we present a new approach for semantic similarity measuring by taking consideration of dissimilarity into the process of computation. Specifically, the proposed measures explore the potential antonymy in the hierarchical structure of WordNet to represent the dissimilarity between concepts and then combine the dissimilarity with the results of existing methods to achieve semantic similarity results. The relation between parameters and the correlation value is discussed in detail. The proposed model is then applied to different text granularity levels to validate the correctness on similarity measurement. Experimental results show that the proposed approach not only achieves high correlation value against human ratings but also has effective improvement to existing path-distance based methods on the word similarity level, in the meanwhile effectively correct existing sentence similarity method in some cases in Microsoft Research Paraphrase Corpus and SemEval-2014 date set.

scholarly journals A New Approach to Inform Restoration and Management Decisions for Sustainable Apiculture

2021 ◽  
Vol 13 (11) ◽  
pp. 6109
Author(s):  
Joanne Lee Picknoll ◽  
Pieter Poot ◽  
Michael Renton
Keyword(s):  
Floral Resources ◽  
Pollination Services ◽  
New Approach ◽  
Honey Production ◽  
Proposed Model ◽  
Colony Loss ◽  
Supply Potential ◽  
Australian Case ◽  
Stocking Rates

Habitat loss has reduced the available resources for apiarists and is a key driver of poor colony health, colony loss, and reduced honey yields. The biggest challenge for apiarists in the future will be meeting increasing demands for pollination services, honey, and other bee products with limited resources. Targeted landscape restoration focusing on high-value or high-yielding forage could ensure adequate floral resources are available to sustain the growing industry. Tools are currently needed to evaluate the likely productivity of potential sites for restoration and inform decisions about plant selections and arrangements and hive stocking rates, movements, and placements. We propose a new approach for designing sites for apiculture, centred on a model of honey production that predicts how changes to plant and hive decisions affect the resource supply, potential for bees to collect resources, consumption of resources by the colonies, and subsequently, amount of honey that may be produced. The proposed model is discussed with reference to existing models, and data input requirements are discussed with reference to an Australian case study area. We conclude that no existing model exactly meets the requirements of our proposed approach, but components of several existing models could be combined to achieve these needs.

scholarly journals Remaining Useful Life Prediction for Rotating Machinery Based on Optimal Degradation Indicator

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Aisong Qin ◽  
Qinghua Zhang ◽  
Qin Hu ◽  
Guoxi Sun ◽  
Jun He ◽  
...  
Keyword(s):  
Health Management ◽  
Rotating Machinery ◽  
Remaining Useful Life ◽  
Programming Algorithm ◽  
Wiener Model ◽  
New Approach ◽  
Degradation Modeling ◽  
Proposed Model ◽  
Useful Life ◽  
Degradation Indicator

Remaining useful life (RUL) prediction can provide early warnings of failure and has become a key component in the prognostics and health management of systems. Among the existing methods for RUL prediction, the Wiener-process-based method has attracted great attention owing to its favorable properties and flexibility in degradation modeling. However, shortcomings exist in methods of this type; for example, the degradation indicator and the first predicting time (FPT) are selected subjectively, which reduces the prediction accuracy. Toward this end, this paper proposes a new approach for predicting the RUL of rotating machinery based on an optimal degradation indictor. First, a genetic programming algorithm is proposed to construct an optimal degradation indicator using the concept of FPT. Then, a Wiener model based on the obtained optimal degradation indicator is proposed, in which the sensitivities of the dimensionless parameters are utilized to determine the FPT. Finally, the expectation of the predicted RUL is calculated based on the proposed model, and the estimated mean degradation path is explicitly derived. To demonstrate the validity of this model, several experiments on RUL prediction are conducted on rotating machinery. The experimental results indicate that the method can effectively improve the accuracy of RUL prediction.

Understanding the electrical behavior of the action potential in terms of elementary electrical sources

2015 ◽  
Vol 39 (1) ◽  
pp. 15-26 ◽  
Author(s):  
Javier Rodriguez-Falces
Keyword(s):  
Action Potential ◽  
Action Potentials ◽  
Present Report ◽  
Electrical Potential ◽  
Ionic Currents ◽  
New Approach ◽  
Electrical Potentials ◽  
Proposed Model ◽  
Ionic Mechanisms ◽  
Human Electrophysiology

A concept of major importance in human electrophysiology studies is the process by which activation of an excitable cell results in a rapid rise and fall of the electrical membrane potential, the so-called action potential. Hodgkin and Huxley proposed a model to explain the ionic mechanisms underlying the formation of action potentials. However, this model is unsuitably complex for teaching purposes. In addition, the Hodgkin and Huxley approach describes the shape of the action potential only in terms of ionic currents, i.e., it is unable to explain the electrical significance of the action potential or describe the electrical field arising from this source using basic concepts of electromagnetic theory. The goal of the present report was to propose a new model to describe the electrical behaviour of the action potential in terms of elementary electrical sources (in particular, dipoles). The efficacy of this model was tested through a closed-book written exam. The proposed model increased the ability of students to appreciate the distributed character of the action potential and also to recognize that this source spreads out along the fiber as function of space. In addition, the new approach allowed students to realize that the amplitude and sign of the extracellular electrical potential arising from the action potential are determined by the spatial derivative of this intracellular source. The proposed model, which incorporates intuitive graphical representations, has improved students' understanding of the electrical potentials generated by bioelectrical sources and has heightened their interest in bioelectricity.

scholarly journals Environmentally Benign Neem Biodiesel Synthesis Using Nano-Zn-Mg-Al Hydrotalcite as Solid Base Catalysts

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Karthikeyan Chelladurai ◽  
Manivannan Rajamanickam
Keyword(s):  
Methyl Esters ◽  
Catalytic Performance ◽  
Environmentally Benign ◽  
Bet Surface Area ◽  
Molar Ratio ◽  
Solid Base ◽  
Synthetic Compound ◽  
Solid Base Catalysts ◽  
Base Catalysts ◽  
Biodiesel Synthesis

Hydrotalcite, also known as aluminum-magnesium layered double hydroxide (LDH) or anionic clay, is a synthetic compound that was broadly investigated in the past decade due to its many potential applications. In this work, we present an environmentally benign process for the transesterification (methanolysis) of neem oil to fatty acid methyl esters (FAME) using Zn-Mg-Al hydrotalcites as solid base catalysts in a heterogeneous manner. The catalysts were characterized by XRD, FT-IR, TPD-CO2, and the BET surface area analysis. It is well-known that the catalytic performance of hydrotalcite is dramatically increased through the incorporation of Zn into the surface of Mg-Al hydrotalcite material. The optimized parameters, 10 : 1 methanol/oil molar ratio with 7.5 g catalysts reacted under stirring speed 450 rpm at 65°C for 4 h reaction, gave a maximum ester conversion of 90.5% for the sample with Zn-Mg-Al ratio of 3 : 3 : 1.

A new approach to the M/G/1 processor-sharing queue

1984 ◽  
Vol 16 (1) ◽  
pp. 202-213 ◽  
Author(s):  
R. Schassberger
Keyword(s):  
Residence Time ◽  
Discrete Time ◽  
Round Robin ◽  
Processor Sharing ◽  
New Approach ◽  
Approximating Sequence ◽  
Residence Time Distributions

The M/G/1 processor-sharing queue is studied by way of an approximating sequence of models featuring a round-robin discipline and operating in discrete time. In particular, residence-time distributions of jobs are derived.

scholarly journals A New Approach to Improve Accuracy of Grey Model GMC(1,n)in Time Series Prediction

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Sompop Moonchai ◽  
Wanwisa Rakpuang
Keyword(s):  
Prediction Accuracy ◽  
Time Series Prediction ◽  
Electricity Consumption ◽  
Prediction Equation ◽  
Grey Model ◽  
System Behavior ◽  
New Approach ◽  
Proposed Model ◽  
Improve Accuracy ◽  
Relative Factors

This paper presents a modified grey model GMC(1,n)for use in systems that involve one dependent system behavior andn-1relative factors. The proposed model was developed from the conventional GMC(1,n)model in order to improve its prediction accuracy by modifying the formula for calculating the background value, the system of parameter estimation, and the model prediction equation. The modified GMC(1,n)model was verified by two cases: the study of forecasting CO2emission in Thailand and forecasting electricity consumption in Thailand. The results demonstrated that the modified GMC(1,n)model was able to achieve higher fitting and prediction accuracy compared with the conventional GMC(1,n)and D-GMC(1,n)models.

PROVIDING A DEPENDABLE OPERATION OF THE DATA PROCESSING SYSTEM WITH INTERVAL CHANGES IN THE FLOW CHARACTERISTICS BASED ON ANALYTICAL SIMULATIONS

2021 ◽  
Vol 2021 (3-4) ◽  
pp. 25-30
Author(s):  
Kirill Tkachenko
Keyword(s):  
Data Processing ◽  
Flow Characteristics ◽  
Processing System ◽  
Data Processing System ◽  
New Approach ◽  
Analytical Simulation ◽  
Proposed Model ◽  
Computing Node ◽  
Computer Node ◽  
Adequate Data

The article proposes a new approach for adjusting the parameters of computing nodes being a part of a data processing system based on analytical simulation of a queuing system with subsequent estimation of probabilities of hypotheses regarding the computing node state. Methods of analytical modeling of queuing systems and mathematical statistics are used. The result of the study is a mathematical model for assessing the information situation for a computing node, which differs from the previously published system model used. Estimation of conditional probabilities of hypotheses concerning adequate data processing by a computing node allows making a decision on the need of adjusting the parameters of a computing node. This adjustment makes it possible to improve the efficiency of working with tasks on the computing node of the data processing system. The implementation of the proposed model for adjusting the parameters of the computer node of the data processing system increases both the efficiency of process applications on the node and, in general, the efficiency of its operation. The application of the approach to all computing nodes of the data processing system increases the dependability of the system as a whole.

Sign in / Sign up

Export Citation Format

Share Document