The Contribution of Niobium Bearing Steels and Enhanced Sustainability

With the growing concern for the environmental impact of greenhouse gases and the rapid depletion of important resources,the use of Nb-bearing steels for advanced high strength steel applications can reduce raw material usage and the carbon footprint.The conservation and more efficient use of ironmaking and steelmaking raw materials is an urgent issue for steel producers globally.Recently-developed Nb-microalloyed steel applications provide a more effective product design and reduce CO 2 emissions and energy consumption per tonne of steel.A sustainability structural steelstudy presents the positive cost and reduced environmental impact of Nb-microalloyed steels.This analysis compares the CO 2 emission reduction and energy savings in the steelmaking process melted in both the Basic Oxygen Furnace (BOF) and the Electric Arc Furnace (EAF).Nb-microalloyed structural steels offer the opportunity to reduce the total weight of a given structure compared to a non-microalloyed steel construction.Generally,one considers the savings associated with less material and lower construction costs.In addition,there is an environmental benefit in the reduction in emissions (kilograms of CO 2) and less energy consumption (GJ) due to the fact that less steel is melted.Plus,there are lighter sections and less material weight in the final end user design which reduces transportation and fabrication costs.A forecasted trend is presented which introduces an increased usage of microalloyed steel grades to replace traditional commodity-type non-alloyed higher carbon-manganese grades for environmental benefits and significant cost reduction.

The Spectral Analysis and Application of Low-degree Modified Spheroidal Hotine Kernel

The traditional spheroidal kernel results in the spectrum leakage,and the utilization rate of the removed degrees of the measured data is low.Hence,a kind of spheroidal kernel whose high-and low-degrees are both modified is introduced in this research,which is exampled by the Hotine kernel.In addition,the low-degree modified spheroidal kernel is proposed.Either cosine or linear modification factors can be utilized.The modified kernel functions can effectively control the spectrum leakage compared with the traditional spheroidal kernel.Furthermore,the modified kernel augments the contribution rate of the measured data to height anomaly in the modified frequency domain.The experimental results show that the accuracy of the quasi-geoid by the cosine or linear low-degree modified kernel is higher than that by the traditional spheroidal kernel.And the accuracy equals the accuracy of the quasi-geoid using the spheroidal kernel with high-and low-degrees modified approximately when the low-degree modification bandwidths of these two kinds of kernels are the same.Since the computational efficiency of the low-degree modified kernel is much higher,the low-degree modified kernel behaves better in constructing the(quasi-)geoid based on Stokes-Helmert or Hotine-Helmert boundary-value theory.