A Novel Macroscopic Traffic Model based on Distance Headway

A new model is proposed to characterize changes in traffic at transitions. These changes are affected by driver response. The distance headway between vehicles is considered as it affects driver behavior. Driver response is quick with a small distance headway and slow when the distance headway is large. The variations in traffic are greater with a slow driver while traffic is smooth with a quick driver. A model is developed which characterizes traffic based on driver response and distance headway. This model is compared with the well-known and widely employed Zhang and PW models. The Zhang model characterizes driver response at transitions using an equilibrium velocity distribution and ignores distance headway and driver response. Traffic flow in the PW model is characterized using only a velocity constant. Roe decomposition is employed to evaluate the Zhang, PW, and proposed models over a 270 m circular (ring) road. Results are presented which show that Zhang model provides unrealistic results. The corresponding behavior with the proposed model has large variations in flow with a slow driver but is smooth with a quick driver. The PW model provides smooth changes in flow according to the velocity constant, but the behavior is unrealistic because it is not based on traffic physics. Doi: 10.28991/CEJ-SP2021-07-03 Full Text: PDF

A Macroscopic Traffic Model based on Driver Reaction and Traffic Stimuli

A new macroscopic traffic flow model is proposed, which considers driver presumption based on driver reaction and traffic stimuli. The Payne–Whitham (PW) model characterizes the traffic flow based on a velocity constant C 0 which results in unrealistic density and velocity behavior. Conversely, the proposed model characterizes traffic behavior with velocities based on the distance headway. The performance of the proposed and PW models is evaluated over a 300 m circular road for an inactive bottleneck. The results obtained show that the traffic behavior with the proposed model is more realistic.

An Identification Method of Failure Mechanism Consistency for Rubber Materials in Accelerated Aging Testing

The failure mechanism of rubber materials under accelerated stress in aging process may be different from that under normal conditions. Therefore, identification of the failure mechanism consistency is necessary for the accelerated aging testing of rubber material. To solve the problem, we study the relationship between the aging velocity of permanent compression set value and aging time. Firstly, according to the relationship, the aging velocity constant is obtained through the least square method. Then, combining with the aging velocity constant, we found that the activation energy is equal to the slope of linear function about Arrhenius model. Based on that failure activation energy keeps same under same failure mechanism, an identification method about failure mechanism consistency is developed. Finally, to demonstrate and validate the proposed method, we take the accelerated aging testing for the nitrile rubber-26 sealing gasket as an example.

The Inhibitory Effect of Salinity Anaerobic Microorganism Based on Kinetics Model

This paper compares the inhibitory effect of high CaCl2and MgCl2content on anaerobic microorganism based on kinetics model. Salt inhibition kinetics experiments were performed at granular sludge and activated sludge in order to investigate salt inhibition effects on kinetic constants. Half-velocity constantvalues considerably increased when CaCl2or MgCl2concentration increased from 0 to 35g/L for granular sludge and activated sludge. Salt inhibition biokinetic coefficients (Kρ) were obtained by using Ghose and Tyagi model. For granular sludge,Kρof CaCl2was found to be 130.3 g/L, andKρof MgCl2was found to be 86 g/L. For activated sludge,Kρof CaCl2was found to be 92.8 g/L, andKρof MgCl2was found to be 77.6 g/L. Results showed that the inhibitory CaCl2limit was higher than the inhibitory MgCl2limit for anaerobic microorganisms.

Research on Adaptive Controlled High Building Slow-Down Rescue Apparatus

t firstly set up energy converting control model of high building rescue apparatus (HBRA), and developed a controller of the HBRA by using AVR micro computer unit (MCU), designed the control circuits for electric energy converting to thermal energy, then developed program to generate the PWM control wave. At last, it tested the PWM output wave of the controller, and experimented on the HBRA with the controller on loads of 15kg and 25kg. The results proves the controller can automatic adjust the duty ratio of PWM wave according to the different loads, which can keep the slow-down velocity constant of the loads and help people rescue from high buildings in emergency such as on fire.

Evaluation of Shelf Life and Heat Treatment of Tomato Products

Model storage experiments of pasteurised tomato puree and ketchup were carried out. The sets of samples were boiled at 100°C, during the heating the changes of selected markers were followed and correlated with the sensory evaluation, the markers were: furosine, 2-furaldehyde, 5-hydroxymethyl-2-furaldehyde (HMF) and colour (expressed as: <I>L, a*, b*, a*/b*</I> and &Delta;<I>E</I>). The suitability of selected markers for the assessment of temperature impact on tomato products was evaluated. The correlation matrix for the followed markers of the tomato puree and ketchup was calculated and the courses of changes (expressed as velocity constant) of the markers were compared.

Monocarboxylate transporters, blood lactate removal after supramaximal exercise, and fatigue indexes in humans

The present study investigated whether muscular monocarboxylate transporter (MCT) 1 and 4 contents are related to the blood lactate removal after supramaximal exercise, fatigue indexes measured during different supramaximal exercises, and muscle oxidative parameters in 15 humans with different training status. Lactate recovery curves were obtained after a 1-min all-out exercise. A biexponential time function was then used to determine the velocity constant of the slow phase (γ2), which denoted the blood lactate removal ability. Fatigue indexes were calculated during 1-min all-out (FIAO) and repeated 10-s (FISprint) cycling sprints. Biopsies were taken from the vastus lateralis muscle. MCT1 and MCT4 contents were quantified by Western blots, and maximal muscle oxidative capacity ( Vmax) was evaluated with pyruvate + malate and glutamate + malate as substrates. The results showed that the blood lactate removal ability (i.e., γ2) after a 1-min all-out test was significantly related to MCT1 content ( r = 0.70, P < 0.01) but not to MCT4 ( r = 0.50, P > 0.05). However, greater MCT1 and MCT4 contents were negatively related with a reduction of blood lactate concentration at the end of 1-min all-out exercise ( r = −0.56, and r = −0.61, P < 0.05, respectively). Among skeletal muscle oxidative indexes, we only found a relationship between MCT1 and glutamate + malate Vmax ( r = 0.63, P < 0.05). Furthermore, MCT1 content, but not MCT4, was inversely related to FIAO ( r = −0.54, P < 0.05) and FISprint ( r = −0.58, P < 0.05). We concluded that skeletal muscle MCT1 expression was associated with the velocity constant of net blood lactate removal after a 1-min all-out test and with the fatigue indexes. It is proposed that MCT1 expression may be important for blood lactate removal after supramaximal exercise based on the existence of lactate shuttles and, in turn, in favor of a better tolerance to muscle fatigue.