Effect of Speed and Boot Opening on Aerodynamics, Fuel Consumption, and CO2 Emission of Minibus

Overspeeding and overloading contribute to road accidents. In developing countries, overloading is often indicated by open boot due to commercial transporters’ motivation to carry an excess load to boost revenue. Therefore, there is a need to provide measures to control or eliminate the practice of overspeeding and overloading. This study aims to conduct a parametric study to determine the effect of vehicle speed and boot opening on the aerodynamics of airflow around a typical minibus, fuel consumption, and CO2 emission, and recommend optimum boot opening. Computational Fluid Dynamics is employed using the FLUENT™ program. Results show the existence of a wavy pattern for drag coefficient, fuel consumption, and CO2 emission concerning boot opening. Furthermore, two boot opening regions exist: and . The first region exhibits low prediction error (maximum of 7.25%) and better fit of regression model to FLUENT™ data. The first region also has lower susceptibility to exhibit handling instability. Therefore, boot opening around is recommended as the optimum boot opening, to ensure minimum fuel consumption and CO2 emissions, improve handling and safety. The developed regression models could inform regulatory bodies’ formulation and implementation of policies to mitigate road accidents. Keywords—Boot Opening, CO2 emission, Fuel Consumption, Pressure drag, Total Drag, Minibus, Viscous Drag

Impact of Overloaded School Backpacks: An Emerging Problem

The possible adverse effects of overloading students' backpacks are a public concern and should be considered by the scientific and educational community. This topic has gained particular importance due to the childhood development process, which can increase the promotion of future disorders (e.g., back pain, low back pain, spinal column deviations). In this brief review, we critically analyze the impact of excess load in students' backpacks and attempt to identify solutions that can be useful to minimize the effects of this problem. It is necessary to find a viable alternative to classic backpacks that can contribute to minimizing the effects of backpack loads on children.

Performance of Francis Turbine Operating at Excess Load Condition

Computational fluid dynamics simulations are conducted to characterize the spatial and temporal characteristics of the flow field inside a Francis turbine operating in the excess load regime. A high-fidelity Large Eddy Simulation (LES) turbulence model is applied to investigate the flow-induced pressure fluctuations in the draft tube of a Francis Turbine. Probes placed alongside the wall and in the center of the draft tube measure the pressure signal in the draft tube, the pressure over the turbine blades, and the power generated to compare against previous studies featuring design point and partial load operating conditions. The excess load is seen during Francis turbines in order to satisfy a spike in the electrical demand. By characterizing the flow field during these conditions, we can find potential problems with running the turbine at excess load and inspire future studies regarding mitigation methods. Our studies found a robust low-pressure region on the edges of turbine blades, which could cause cavitation in the runner region, which would extend through the draft tube, and high magnitude of pressure fluctuations were observed in the center of the draft tube.

Association of Maternal Iodine Intake with Congenital Hypothyroidism

The iodine intake in a pregnant woman has been closely correlated with development of transient congenital hypothyroidism which leads to decline in neurocognitive abilities of the child later in life as the effects are very subtle at birth. Both low and excess ingestion of iodine has been found to contribute to this cause, although iodine deficiency is more commonly observed in women of underdeveloped nations. It poses risks not only to the foetus but also to the mother leading to obstetric complications such as still birth and spontaneous abortions. It can be prevented using WHO recommended daily iodine supplementation in deficient regions or decreasing the excess load in groups exposed to high iodine. Programmes designed to screen the new-born at birth can also help in improving the quality of life of the child. The deficient iodine condition is managed by administration of levothyroxine in dosage range of 10-15 mcg/kg/day. Generally, the prognosis of infants starting treatment early in life have a better neurocognitive outcome as compared to the treated infants late age at a later age. Avoidance of agents causing iodine exposure has resulted in decrease in the abnormal thyroid function levels.

Failure analysis and repair of the telescopic beam belonging to the spreader of a reach stacker for port operations

Reach stackers land equipment operating in ports of the Colombian Caribbean, are subject to several critical working conditions such as; corrosive environment, excess working hours, overload and lack of predictive maintenance. This work focuses on the failure analysis and the elaboration of the welding repair procedure of the telescopic beam belonging to the spreader of a Reach stacker that operates in a Colombian Caribbean seaport. Initially the fault zone was characterized; by mean a metallographic analysis and a hardness profile to identify the type of structural steel of which the beam is composed, obtaining an A514 grade C of 110KSI of tensile strength and 34HRC of hardness. The equipment manufacturer was verified and the established by the laboratory tests was corroborated. After identifying the material, the fracture area was analyzed where patterns of beach markings were found, typical of a fatigue failure which extended from the circumference of separating pins to the surface of the beam. The inclusion of the separators in the initial design generates stress concentrators in the welding of the pins which increases the fatigue zone combined with the excess load with which the equipment works. This fact could be verified with a technical bulletin published by the manufacturer brand "Taylor" where it indicates this type of failure for the telescopic beam of the Reach stackers. Successively, an FCAW type welding repair procedure is developed in accordance with AWS code D1.1, where the electrode to be used, the cords to be applied, the preheating, and the speeds and conditions recommended for filling the materials are selected cracks. Finally it could be concluded that the fault was generated by fatigue and overload in the welding of the telescopic beam separator pins and its repair will be carried out according to a welding procedure of the AWS code D1.1. The analysis of these types of cases will allow the company to take actions to minimize the new occurrence of the failure such as periodic reviews in that area after the work hours recommended by the manufacturer and the awareness of the equipment operators with the handling of loads on the dock.