Effects of Vehicle Load on Emissions of Heavy-Duty Diesel Trucks: A Study Based on Real-World Data

Vehicle loads have significant impacts on the emissions of heavy-duty trucks, even in the same traffic conditions. Few studies exist covering the differences in emissions of diesel semi-trailer towing trucks (DSTTTs) with different loads, although these vehicles have a wide load range. In this context, the operating modes and emission rates of DSTTTs were analyzed under varying loads scenarios to understand the effect of vehicle loads on emission factors. First, second-by-second field speed data and emission data of DSTTTs with different loads were collected. Then, the methods for calculating the scaled tractive power (STP) and the emissions model for DSTTTs were proposed to evaluate the effect of different loading scenarios. The STP distributions, emission rate distributions, and emission factor characteristics of different loaded trucks were analyzed and compared. The results indicated that the STP distributions of DSTTTs that under the unloaded state were more narrow than those under fully loaded or overloaded conditions. The emission rates of carbon dioxide (CO2), carbon monoxide (CO) and total hydrocarbon (THC) for DSTTTs under a fully loaded state were significantly higher than those under an unloaded state. However, due to the influence of exhaust temperature, the emission rates of nitrogen oxides (NOx) among fully loaded trucks were lower than those under the unloaded state when STP bin was above 4 kW/ton. The emission factors of CO2, CO, THC, and NOx for fully loaded trucks demonstrated the largest increases at low-speed intervals (0–30 km/h), which rose by 96.2%, 47.9%, 27.8%, and 65.2%, respectively.

Kendali Motor DC Brushless Modifikasi Mengunakan IC Ne555 Dan CD4017

In general, the Brushless DC motor speed controller uses an Atmega 16 microcontroller and a MOSFET, which often increases the MOSFET's temperature, especially when the motor is loaded. This article discusses the use of the IC NE555 and CD4017 as a frequency regulator to the MOSFET gate by periodically igniting the forward voltage from the change in the potentiometer value. We carried out the test in an unloaded and unloaded state with voltage variations of 2.5 Vac, 7.5 Vac, 12.5 Vac, and 19.5 Vac. The test results show an excellent tool response where the higher the frequency value, the motor speed will increase. The maximum speed when unloaded reaches rpm at a frequency of 574.6. Whereas in the load test, the full speed reaches 20987 rpm at a frequency of 524.675 Hz. During the test, there was no temperature increase in the MOSFET.

TRANSVERSE BENDING AND FREE VIBRATIONS OF ELASTIC ISOTROPIC PLATES IN THE FORM OF ISOSCELES TRIANGLES

This paper considers elastic isotropic plates in the form of isosceles triangles with combined boundary conditions (a combination of hinged support and rigid restraint conditions along the sides of the contour). Calculations were performed using FEM to determine the integral physical characteristics in the considered problems F (the maximum deflection of uniformly loaded plates w0 and the fundamental frequency of oscillations in the unloaded state ω). On the basis of the obtained numerical results, approximating functions have been constructed: "maximum deflection - form factor of plates", "basic frequency of oscillations - form factor of plates", the structure of which corresponds to the structure of similar formulas obtained when presenting known exact solutions in the corresponding problems of technical theory of plates in isoperimetric form. Based on the properties of the form factor of plates, these approximating functions limit the whole set of considered integral physical quantities and therefore can be used as reference solutions for the calculation of triangular plates of arbitrary form applying the method of interpolation by form factor (MIFF). We consider an example of calculation of a plate in the form of a rectangular triangle with hinged support of the sides.

Regional and Layer Distribution of Residual Stresses in an Unloaded Aortic Medial Wall

The mechanical and structural characteristics of aortic media have profound effects on the physiology and pathophysiology of an aorta. However, many aspects of the aortic tissue remain poorly understood, partly due to the intrinsic layered wall structure and regionally varying residual stresses. Our recent works have demonstrated that a mechanical interaction between the elastic lamina (EL) and smooth muscle layer in the aortic media can be computationally reproduced using a simplified finite element (FE) model. However, it is questionable whether the simplified FE model we created was representative of the structure of a real medial wall and its modeling technique would be applicable to develop a more sophisticated and structure-based aortic FE model. This study aimed to computationally represent EL buckling in the aortic medial ring at an unloaded state and successfully reproduced transmural variation in EL waviness across the aortic wall. We also aimed at confirming the inner and outer layers of the medial wall are subjected to compressive and tensile residual stresses, respectively, at the unloaded state, implying that the ring model will open spontaneously when it is radially cut. Moreover, the computed residual stresses were found to be within the reasonable range of the predicted values, 1–10 kPa, supporting the validity of our modeling approach. Although further study is required, the information obtained here will greatly help improve the understanding of basic aortic physiology and pathophysiology, while simultaneously providing a basis for more sophisticated computational modeling of the aorta.

State Monitoring of Polymer Composites with Glass Optical Fibre and with Equipment Used in Telecommunication

Thanks to the widespread use of optical fibers in telecommunication, they, and their accompanying equipment have become cost-effective and easily accessible. We have proved that the changed attenuation of a monomodal optical fiber built into a polymer composite can indicate the elongation of the structure compared to its original, unloaded state, before the optical fiber breaks. We also proved that the location of deformation in polymer composite structures can be found with OTDR equipment (used for checking the coupling of optical fibers).

Modeling Prestress-Driven Buckling Behavior of Elastic Lamina in the Aortic Media

Mathematical modeling of the thoracic aorta is important for understanding the development and progression of various cardiovascular diseases, helping to detect extraordinary stress distributions of the hypertensive aortic wall, even in early stages. However, it is difficult to ensure the biofidelity of biological materials in formulating a mathematical model. In a freshly isolated aortic media, composed mainly of smooth muscle cell layers (SMLs) and elastic laminae (ELs), circumferential EL waviness and longitudinal EL undulation are often observed because of the structural “buckling” of ELs. This is considered to be closely associated with residual stresses of SMLs and ELs in the aortic wall but the mechanism underlying such EL buckling behavior remains unclear. In the present study, a series of numerical simulations were designed to identify effective mechanical parameters to reproduce EL buckling in the aortic media. We found that prestress initially administered to ELs in the circumferential and axial directions, and the predefined internodal distance, which couples the SML and EL, are essential to computationally reconstruct the circumferential EL waviness and the longitudinal EL undulation in an unloaded state. We also proposed a set of equations based on the numerical results and successfully predicted EL buckling behaviors of the aorta in vitro.

THE USAGE OF TLS AND PHOTOGRAMMETRY DURING THE RESTORATION PROCESS OF SPANISH NATIONAL MONUMENT

<p><strong>Abstract.</strong> This article presents the multidisciplinary methodology employed in the restoration of a sixteenth century renaissance building with gothic vaults. The use of precise instrumental techniques like TLS (Terrestrial Laser Scanning) or photogrammetry are proposed to obtain the geometry of the building before, during and after the intervention. Obtaining the point clouds of the Refectory of the Santo Domingo de Orihuela School in their different restoration stages allows monitoring the vaults, studying their structural behaviour and deformations with the comparison of their original state, unloaded state and the new loading after the execution works.</p><p>A work methodology that is proposed in this article could be applied to any restoration work of patrimonial architecture. The original deformations have been verified and quantified and the final state of the intervention has been documented with respect to the original state.</p>

COMPARISON OF TWO METHODS FOR ESTIMATING THE UNLOADED STATE FOR ABDOMINAL AORTIC ANEURYSM STRESS CALCULATIONS

Biomechanical analyses can be used to better understand the rupture risk of abdominal aortic aneurysms (AAAs) on a patient-specific basis using vascular geometries obtained from medical imaging. Methodologies of varying complexity are used to estimate the unloaded state of the imaged vessel to provide a reference configuration for finite element simulations. In this work, we compare the implementation and results of two of these methods, one based on geometric scaling and the other using an iterative determination of unloaded vessel geometry. We find that the two methods result in significantly different stress predictions, and that the iterative method offers superior geometric accuracy. Our findings lend context to the variation in finite element results presented in the AAA stress analysis literature.

Reproduction of Kinematic Behavior of Elastic Lamellae in the Thoracic Aortic Media

The thickening of the aortic wall is a mechanical adaptation to the prolonged increase in intravascular pressure resulting from hypertension, which is regulated by the smooth muscle cell layer (SML) and the elastic lamina (EL). Herein, we built a simplified computational model of the aortic media composed of SML and EL and simulated the phenomenon of EL undulation or EL buckling at no-load condition (in vitro) by releasing compressive prestress assigned to the EL. Using the design of experiments approach, we found that the prestress assigned to the EL, the thickness of the EL, and a coupled or interspace connecting length between the SML and the EL are significantly influential factors in representing EL buckling at the unloaded state. We also found that the degree of EL waviness and the change in residual stresses within the SML and the EL are inversely correlated. Furthermore, by increasing the stiffness of the SML, we successfully reconstructed the disappearance of EL undulation at 25% stretch, replicating the dilation of a normal aorta under physiological loading conditions. It can be expected that these findings will help unveil the roles of the SML and the EL in maintaining the mechanical homeostasis of the arterial wall.