Recent Studies on Alternative Fuel of Dimethyl Ether

With the development of industrialization, a large number of non-renewable fuels (such as coal and crude oil) are consumed, and the harmful substances produced in the combustion process of a large number of fossil fuels have caused serious pollution to the atmosphere, and the harmful gases produced by combustion have caused disastrous damage to the ecological balance. Therefore, finding clean energy and exploring alternative fuels are very important in today's society. This paper mainly reviews the studies on the alternative fuels of dimethyl ether (DME). Firstly, the types of alternative fuels currently researched by society and their respective advantages and disadvantages are analyzed, and the preparation of dimethyl ether and its advantages and disadvantages are analyzed in detail. In addition, the physicochemical properties, combustion and emission characteristics of dimethyl ether and diesel are compared and analyzed. The conclusion is that the injection delay angle of dimethyl ether is larger than that of diesel, the ignition delay period is shorter than that of diesel, and the maximum explosion pressure, maximum pressure rise rate and combustion noise of dimethyl ether are lower than that of diesel. The diffusion combustion speed of DME is faster than that of diesel, and the combustion duration is shorter than that of diesel. At the same time, as an alternative energy, dimethyl ether engine has a significant reduction in NOx emission, a very low level of HC and CO emission, and zero soot emission. In conclusion, the DME engine has good performance and emission characteristics.Citation: Zhang, J. (2022). Recent Studies on Alternative Fuel of Dimethyl Ether. Trends in Renewable Energy, 9(1), 1-10. DOI: 10.17737/tre.2023.9.1.0014

A deformed Hermitian Yang-Mills Flow

We study a new deformed Hermitian Yang-Mills Flow in the supercritical case. Under the same assumption on the subsolution as Collins-Jacob-Yau \cite{cjy2020cjm}, we show the longtime existence and the solution converges to a solution of the deformed Hermitian Yang-Mills equation which was solved by Collins-Jacob-Yau \cite{cjy2020cjm} by the continuity method.Comment: This version is more readable and some references are adde

Analysis of a duopoly game with heterogeneous players participating in carbon emission trading

In this paper, a price competition model with two heterogeneous players participating in carbon emission trading is formulated. The stable conditions of the equilibrium points of this system are discussed. Numerical simulations are used to show bifurcation diagrams, strange attractors, and sensitive dependence on initial conditions. We observe that the speed of adjustment of bounded rational player may change the stability of the Nash equilibrium and cause the system to behave chaotically. In addition, we find that the price of emission permits plays an important role in the duopoly game. The chaotic behavior of the system has been stabilized on the Nash equilibrium point by applying delay feedback control method

The parabolic quaternionic Monge-Amp\`{e}re type equation on hyperK\"{a}hler manifolds

We prove the long time existence and uniqueness of solution to a parabolic quaternionic Monge-Amp\`{e}re type equation on a compact hyperK\"{a}hler manifold. We also show that after normalization, the solution converges smoothly to the unique solution of the Monge-Amp\`{e}re equation for $(n-1)$-quaternionic psh functions

An Approximate Algorithm Combining P Systems and Ant Colony Optimization for Traveling Salesman Problems

This paper proposes an approximate optimization algorithm combining P systems with ant colony optimization, called ACOPS, to solve traveling salesman prob- lems, which are well-known and extensively studied NP-complete combinatorial optimization problems. ACOPS uses the pheromone model and pheromone update rules defined by ant colony optimization algorithms, and the hierarchical membrane structure and transformation/communication rules of P systems. First, the parameter setting of the ACOPS is discussed. Second, extensive experiments and statistical analysis are investigated. It is shown that the ACOPS is superior to Nishida's algorithms and its counterpart ant colony optimization algorithms, in terms of the quality of solutions and the number of function evaluations

The Monge-Amp\`{e}re equation for (n−1)(n-1)-quaternionic PSH functions on a hyperK\"{a}hler manifold

We prove the existence of unique smooth solutions to the quaternionic Monge-Amp\`{e}re equation for $(n-1)$-quaternionic plurisubharmonic functions on a hyperK\"{a}hler manifold and thus obtain solutions for the quaternionic form type equation. We derive $C^0$ estimate by establishing a Cherrier-type inequality as in Tosatti and Weinkove [22]. By adopting the approach of Dinew and Sroka [9] to our context, we obtain $C^1$ and $C^2$ estimates without assuming the flatness of underlying hyperK\"{a}hler metric comparing to previous results [14].Comment: 31 page

On the connectivity of p-diamond-free vertex transitive graphs

AbstractLet G be a graph of order n(G), minimum degree δ(G) and connectivity κ(G). We call the graph G maximally connected when κ(G)=δ(G). The graph G is said to be superconnected if every minimum vertex cut isolates a vertex.For an integer p≥1, we define a p-diamond as the graph with p+2 vertices, where two adjacent vertices have exactly p common neighbors, and the graph contains no further edges. Usually, the 1-diamond is triangle and the 2-diamond is diamond. We call a graph p-diamond-free if it contains no p-diamond as a (not necessarily induced) subgraph. A graph is vertex transitive if its automorphism group acts transitively on its vertex set.In this paper, we give some sufficient conditions for vertex transitive graphs to be maximally connected. In addition, superconnected p-diamond-free (1≤p≤3) vertex transitive graphs are characterized

The Adsorption Capacity, Pore Structure, and Thermal Behavior of the Modified Clay Containing SSA

Sewage sludge ash (SSA) was created by burning municipal sludge. The potential of clay containing 1 or 3 or 5% SSA was assessed for use as a landfill liner-soil material. Batch adsorption, low temperature N2 adsorption, and TG-DTA tests were performed to evaluate the adsorption capacity, micropore structure, thermostability, and components of soils under Cr(VI) and Pb(II) chemical solutions. With the increasing amount of SSA in modified clay, the adsorption capacity of Cr(VI) and Pb(II) to the modified clay increases gradually. After absorption, the pore size of modified clay ranges from 2 nm to 8 nm. With the increasing amount of absorption, the pore volume decreases and the specific surface area increases. With the increasing of adsorption concentration of Cr(VI) and Pb(II), the mass loss percentage of modified clay increases to 23.4% and 12.6%, respectively. The modified clay containing SSA may be used as a good barrier material to attenuate contamination of Cr(VI) and Pb(II) in landfills

Sliding mode sensorless control of wind turbine pitch motor with ESO feedforward compensation in the offshore wind power system

In order to improve the dynamic performance of the control system, a variable frequency sliding mode sensorless control strategy based on Extended State Observer (ESO) feedforward compensation was proposed in order to improve the disturbance and jitter problems of pitch motors in offshore wind power generation systems. The fast exponential reaching law is designed in the velocity loop, and the integrated sliding surface is adopted, which reduces the steady-state error of the traditional sliding surface and weakens the jitter phenomenon of the moving point on the sliding surface. The traditional sliding mode observer is improved, and the variable cut-off frequency filter is used instead of the low-pass filter in the filtering process to filter the signals of each speed band. At the same time, in order to estimate the disturbances in the system, the Linear Extended State Observer (LESO) is designed to observe and compensate for the unknown disturbances, which improves the robustness of the system. The simulation results show that the control strategy in this paper solves the problems of traditional Sliding Mode Control (SMC), which not only shortens the response time of the system, but also significantly improves the anti-disturbance performance of the system, and the overall effect is significantly improved