Xianfang Yue

Contribution from Urban Heating to China's 2020 Goal of Emission Reduction

To reduce inhalable particle and SO(x) pollution from coal-based urban central heating (UCH), China has been vigorously developing natural gas-based UCH for years. The CO(2) emissions of UCH, having an average annual growth rate of 10.3%, accounted for 4.4% of Chinas total CO(2) emissions in 2009. This paper analyzes the feasibility of replacing UCH with heat pump heating (HPH) in Chinas climatic suitable regions and evaluates the corresponding potential for energy saving and emission reduction. Current strategy of replacing coal-based UCH with natural gas-based UCH is expected to decrease CO(2) emissions by 63.5%. However, the CO(2) emissions of HPH are 55.4% less than those of natural gas-based UCH. Replacing coal-based UCH with HPH is capable of decreasing CO(2) emissions by 83.7% and consequently decreases the CO(2) emissions per unit of gross domestic product (GDP) by 4.2% by 2020 compared with 2005 level. This contributes about 10.5% to Chinas 2020 CO(2) emission reduction target. For controlling environmental pollution and protecting ecological environment better, China should adjust its strategy for CO(2) emission reduction by shifting its attention from replacing coal-based UCH with natural gas-based UCH to popularizing HPH in climatic suitable regions.

Tissue modeling and analyzing with finite element method: a review for cranium brain imaging.

For the structure mechanics of human body, it is almost impossible to conduct mechanical experiments. Then the finite element model to simulate mechanical experiments has become an effective tool. By introducing several common methods for constructing a 3D model of cranial cavity, this paper carries out systematically the research on the influence law of cranial cavity deformation. By introducing the new concepts and theory to develop the 3D cranial cavity model with the finite-element method, the cranial cavity deformation process with the changing ICP can be made the proper description and reasonable explanation. It can provide reference for getting cranium biomechanical model quickly and efficiently and lay the foundation for further biomechanical experiments and clinical applications.

Amendment on the strain measurement of thin-walled human skull shell as intracranial pressure changes

Abstract The human skull, composed of tabula externa, tabula interna, and a porous diploe sandwiched in between, is deformed with changing intracranial pressure (ICP). Because the human skulls thickness is only 6 mm, it is simplified as a thin-walled shell. The objective of this article is to analyze the strain of the thin-walled shell by the stress-strain calculation of a human skull with changing ICP. Under the same loading conditions, using finite element analysis (FEA), the strains of the human skull were calculated and the results were compared with the measurements of the simulative experiment in vitro . It is demonstrated that the strain of the thin-walled shell is totally measured by pasting the one-way strain foils on the exterior surface of the shell with suitable amendment for data. The amendment scope of the measured strain values of the thin-walled shell is from 13.04% to 22.22%.

Finite Element Analysis on Strains of Viscoelastic Human Skull and Duramater

Human skull and duramater has the viscoelasticity.Using the viscoelastic option of the ANSYS finite element program,this study analyzed the deformation of human skull and duramater with the changing ICP (Intracranial Pressure).The strains calculations were performed of three-dimensional finite element model of hollow shell simulating cranial cavity in this paper.The viscoelastic models for human skull and duramater were constructed.The result shows that the viscous strains account for about 40% and the elastic strains about 60% of total strains of human skull and duramater.

Intelligent simulation on refrigeration system using artificial neural network

Because of the dynamic, nonlinear and multi-parameter characteristic of the refrigeration system, it is difficult to keep the system operating under the optimal state. Based on the improved back-propagation (BP) of artificial neural network (ANN) with the momentum factor, the program to predict the performance of refrigeration system at part-load condition is established by Visual C++ 6.0. The training or testing data is from a refrigeration experiment system with HCFC22. The input layer includes 3 neurons, i.e. the indoor and outdoor air temperature and compressor frequency. The prediction result indicates that the artificial neural network method is a kind of effective way to analyze the performance of refrigeration system. This work can provide guidance on the saving-energy control method of refrigeration system at part-load condition.

Tissue Modeling and Analyzing for Cranium Brain with Finite Element Method

Numerous methods for measuring intracranial pressure (ICP) have been described, and many of them are suitable for different clinical disorders [1-5]. One method for ICP monitoring is through the ventricular system [6,7], which requires stereotaxic techniques and may not be practical for surgical experiments in the brain regions. Ventricular monitoring of ICP is also associated with intracerebral hemorrhage and infection [6]. Another method to monitor ICP is through the subarachnoid space at the cisterna magna, in which catheter placement may be difficult and dangerous due to the anatomy [8,9]. Some studies monitored ICP via epidural [10,12], which has limitations in measuring acute changes in ICP and is inaccurate in some cases when compared with ventricular monitoring [8]. These methods have many disadvantages of invasion, low-accuracy, cross-infection, etc [13,14]. Although many efforts have recently been made to improve the minitraumatic or non-invasive methods [15-19], noninvasive means of measuring ICP do not exist unfortunately in clinic [20,21]. With the significance of raised ICP in the studies of intracranial pathophysiology, espacially in neurosurgical disorders, it would be valuable to have a simple and reliable method to monitor intracranial pressure (ICP) in clinic. Therefore, the minitraumatic or non-invasive, accurate and simple method to measure ICP is an important question of research in neurosurgery. In this study, we propose a new, minitraumatic, simple, and reliable measurable system that can be used to monitor ICP from the exterior surface of skull bone.

Potential therapeutic actions of hypothermia: Finite-element simulation of human skull deformation with hypothermia treatment

OBJECTIVE: A quantitative effect of the hypothermia treatment was made on the cranial-cavity deformation with the increasing intracranial pressure (ICP). METHORDS: Finite element software-ANSYS was used to construct a human cranial cavity model, and simulate the deformations with and without hypothermia treatment. RESULTS: The deformation of the cranial-cavity model with hypothermia treatment is 0.56% less on average than the results without hypothermia treatment. CONCLUSION: The influence of hypothermia on the cranial-cavity deformation should be considered in clinical situations.

New Minitraumatic Method for a Simulation of Continuous Intracranial Pressure Curves with Strain Electrometric Technology in Rats

Monitoring intracranial pressure (ICP) is crucial in the study of neurosurgical disorders. In the present study, we propose a new minitraumatic method for monitoring ICP with strain-electrometric technology in rats. Strain foils were placed on the exterior surface of parietal skull to record the strains of skull bone. A small incision was made on the skin in the rat’s head and the area is shaved for about 11 mm2. ICP variation was recorded simultaneously via strain foils on the skull. Three anesthetized adult rats were subjected to baseline recording followed by either experimental raising ICP induced by Middle cerebral artery occlusion (MCAO). A similar acute response was recorded in both the strains and ICP variation. The strain foils continuously and accurately monitored strain–ICP, and reliable pressure tracings were obtained for up to 4h after MCAO. ICP decreased for the leaking blood from the carotid artery. The strains of skull bone can be measurable with the changing ICP. The strains can reflect the ICP change. This new strain-ICP method is simple, safe, reliable, and feasible in rats. Continued strain-ICP measurements provided monitoring for up to 4 h after experimental manipulation.