A Grey Box Neural Network Model of Basal Ganglia for Gait Signal of Patients with Huntington Disease

Introduction: Huntington disease (HD) is a progressive neurodegenerative disease which affects movement control system of the brain. HD symptoms lead to patient’s gait change and influence stride time intervals. In this study, we present a grey box mathematical model to simulate HDdisorders. This model contains main physiological findings about BG. Methods: We used artificial neural networks (ANN) and predetermined data to model healthy state behavior, and then we trained patients with HD with this model. All blocks and relations between them were designed based on physiological findings. Results: According to the physiological findings, increasing or decreasing model connection weights are indicative of change in secretion of respective neurotransmitters. Our results show the simulating ability of the model in normal condition and diferent disease stages. Conclusion: Fine similarity between the presented model and BG physiological structure with its high ability in simulating HD disorders, introduces this model as a powerful tool to analyze HD behavior

A Grey Box Neural Network Model of Basal Ganglia for Gait Signal of Patients with Huntington Disease

Introduction: Huntington disease (HD) is a progressive neurodegenerative disease which affects movement control system of the brain. HD symptoms lead to patient’s gait change and influence stride time intervals. In this study, we present a grey box mathematical model to simulate HDdisorders. This model contains main physiological findings about BG. Methods: We used artificial neural networks (ANN) and predetermined data to model healthy state behavior, and then we trained patients with HD with this model. All blocks and relations between them were designed based on physiological findings. Results: According to the physiological findings, increasing or decreasing model connection weights are indicative of change in secretion of respective neurotransmitters. Our results show the simulating ability of the model in normal condition and diferent disease stages. Conclusion: Fine similarity between the presented model and BG physiological structure with its high ability in simulating HD disorders, introduces this model as a powerful tool to analyze HD behavior

Using novel integrated Maisotsenko cooler and absorption chiller for cooling of gas turbine inlet air

Performance reduction of gas turbine power plants during the hot seasons has persuaded the specialists to propose different inlet air temperature reducer techniques. Accessible free heat at the exhaust of the turbine justifies the absorption chiller as a potential solution. However, based on the evaluations of present research, almost for all climate conditions a huge capacity/size/number of absorption chillers are required to reach the ISO condition (15 °C and RH 100% which is the design point of gas turbine) which means considerable amount of initial, operating and maintenance cost. As the M-cycle cooler (which has very simpler structure and lower costs) is able to reduce the air temperature toward the dew point temperature without adding any moisture, present research proposes an integrated cycle of M-cycle and absorption chiller (which notably reduces the whole cost of the cooling process) for said aim. In present novel cycle, the air is precooled by M-cycle toward its dew point temperature before entering to the absorption chiller which significantly reduces the required capacity of absorption chiller for the rest of the cooling process. The most amazing feature of the integrated cycle is that the condensed water from the air during the cooling process by absorption chiller can be employed as the M-cycle water consumption. For some climate conditions, M-cycle is able to provide ISO condition (or colder temperatures) without the requirement of absorption chiller. Many other outstanding results are obtained which can be used in real industrial applications.Hamed Sadighi Dizaji, Eric Jing Hu, Lei Chen, Samira Pourhedaya

Development and validation of an analytical model for perforated (multi-stage) regenerative M-cycle air cooler

Maisotsenko cycle based coolers are able to reduce the air temperature below the wet-bulb temperature of the inlet air without adding any moisture to the product air and without the use of any compressor or refrigerant (CFC). These positive features of M-cycle have encouraged the researchers to enthusiastically consider the thermal-fluid characteristics of M-cycle cooler via numerical, analytical and experimental techniques. In this paper attempts are made to present an analytical solution for thermal behavior of perforated (multi-stage) regenerative M-cycle exchanger which has not been carried out before. Indeed, all previous analytical solutions of M-cycle have been provided for the simplest structure of M-cycle exchanger (single-stage, without perforation) and the perforated M-cycle cooler (multistage) has been investigated only via experimental and numerical techniques (including finite difference method, numerical ε-NTU technique, statistical design tools all of which are sophisticated and require high computational time). However, the precision aspect and analysis speed of analytical approach is undeniable and it is considered as the priority in most engineering problems. Hence, in this study, an analytical model is developed for three-stage regenerative M-cycle exchanger which can be developed for any number of perforations. All modeling process is described in detail (step by step) to make it ease understanding for readers. Evaluation methods of all required parameters are described in detail as well. Finally, the model is verified with numerical results.Hamed Sadighi Dizaji, Eric Jing Hu, Lei Chen, Samira Pourhedaya

A critique of effectiveness concept for heat exchangers; theoretical-experimental study

In this study attempts are made to clarify some hidden features of effectiveness concept (the ratio of ac- tual heat transfer to maximum possible heat transfer) of heat exchangers and provide a critique viewpoint and comprehensive description about that. It is shown in present paper that the effectiveness parame- ter requires much more attention when it is used in fluid-flow parametric or sensitivity studies of heat exchangers and lack of consideration of its hidden features may lead to incorrect or imperfect decision- makings on curve behavior of effectiveness. Indeed, it is shown that the curve trend of effectiveness against the Reynolds number of one side of heat exchanger can be ascending, descending, or ascending- descending depending on the mass flow rate ( Re number) of the other side fluid. Although this critique viewpoint is not considered as a weakness of the effectiveness definition for heat exchangers, inattention may lead to wrong or imperfect inferences in sensitivity analysis of effectiveness parameter. Moreover, it is not logical to provide empirical correlation for effectiveness against flow parameters without the con- sideration of described features of effectiveness in this study. In order to support the described viewpoint some experiments are performed on double helical tube heat exchanger to evaluate the related thermal parameters and describe the mentioned features of effectiveness statistically. However, the provided anal- ysis is valid for any other type heat exchanger as well.Shu-Rong Yan, Hazim Moria, Samira Pourhedayat, Mehran Hashemian, Soheil Asaadi, Hamed Sadighi Dizaji, Kittisak Jermsittiparser