Coal consumption and industrial production nexus in USA: Cointegration with two unknown structural breaks and causality approaches

The paper investigates the causality relationships among industrial production index, coal consumption and employment in industrial sector for the period of 1973:1–2011:10 in USA. After noticing that there are breaks in the regression model, the Hatemi-J test for cointegration is employed to the cases that take into account two possible regime shifts. It is concluded that there is a long run relationship between industrial production and industrial coal consumption with the breaks at 1983:4 and 1998:4. We found a negative relationship between coal consumption and industrial production for the period of 1973:1–1983:4 and positive relationship for 1983:5–1998:4 period. For the last period that covers 1983:5–2011:10, the cointegration relationship turned to negative. In addition, the results show that causal relationship between coal consumption and industrial production changes over time.     

Prioritization methodology of dangerous substances for water quality monitoring with scarce data

Monitoring and control of dangerous substances discharged into receiving waters have attracted more attention lately. Since it is not possible to analyze every single substance, a prioritization methodology is needed for the selection of those to be monitored. Existing well-developed models require significant amount of data for reliable outcomes. This paper presents a methodology to prioritize the dangerous substances having adverse effects on freshwaters in Turkey, where data are scarce. Such a methodology will also serve as a solid model for other countries with limited background data. The adopted methodology enabled the elimination of chemicals to generate a candidate list composed of 608 substances among more than 5000 substances. Further screening and prioritization were conducted using different assessment methods (i.e., Total Hazard Value, Total Impact Value, Combined Monitoring-based, and Modelling-based Priority Setting) to obtain a proposed Final Candidate Specific Pollutants List of 150 dangerous substances. The proposed Candidate National Pollutant List of Turkey was established by combining 45 priority pollutants of the European Union with a list of candidate specific pollutants. According to the outcomes of this study, monitoring and controlling of 195 dangerous substances in freshwaters are recommended. Further detailed studies should be conducted in order to observe the actual levels of these dangerous substances in freshwaters followed by a review of the monitoring list accordingly. Moreover, further revisions might be required in the proposed list due to some possible versatile conditions in terms of sampling points (i.e., change in the location of industries).     

Antenna miniaturization for vehicular platforms using printed coupled lines emulating magnetic photonic crystals

A miniature printed antenna exploiting magnetic photonic crystal (MPC) modes is presented. The MPC mode is typically found in volumetric anisotropic materials and is realized here using a set of coupled printed transmission lines. The printed element is formed by a pair of unit cells, cascaded to realize a circularly periodic structure. To excite the nonreciprocal MPC mode, the coupled microstrip lines are printed on a uniform substrate with magnetic material inserts. A printed and slot (cavity-backed) version of the MPC-based element is designed and constructed. It is found that the cavity-backed version is better suited for reducing platform interactions, thus, avoiding detuning when installed on smaller platforms. Tunable magnetic biasing is also explored to improve functionality. The paper concludes by providing the in situ performance of the cavity-backed and recessed MPC antennas.     

Boron Compounds as Hydrogen Storage Materials

Abstract

Hydrogen exhibits the highest heating value per mass of all chemical fuels. Furthermore, hydrogen is regenerative and environmentally friendly. Hence, hydrogen storage is very important for humans. Hydrogen storage in metal hydrides is considered as one of the most attractive methods. In the present work, the hydrogen absorption-desorption behavior of the boron compounds has been compared. We present recent developments in the search for hydrogen-storage capacity of boron. Boron compounds have a very high energy density, much better than that of liquid hydrogen and also a lot safer. LiBH₄ is a complex hydride that consists of 18 mass% of hydrogen. It has stability compared with other chemical hydrides and an easy conversion to H₂. Thus, there are a good many reasons that hydrogen-storage materials for LiBH₄ will be used in the future at many ranges for power sources. The future warrants further investigations of the B-H system from the viewpoint of hydrogen energy storage.     

Reliability-Aware Heterogeneous 3D Chip Multiprocessor Design

Ability to stack separate chips in a single package enables three-dimensional integrated circuits (3D ICs). Heterogeneous 3D ICs provide even better opportunities to reduce the power and increase the performance per unit area. An important issue in designing a heterogeneous 3D IC is reliability. To achieve this, one needs to select the data mapping and processor layout carefully. This paper addresses this problem using an integer linear programming (ILP) approach. Specifically, on a heterogeneous 3D CMP, it explores how applications can be mapped onto 3D ICs to maximize reliability. Preliminary experiments indicate that the proposed technique generates promising results in both reliability and performance.     

Lipoprotein Subfraction Profile and HDL-Associated Enzymes in Sickle Cell Disease Patients

Although hypocholesterolemia is a reported finding in sickle cell disease (SCD), low-density lipoprotein (LDL)/high-density lipoprotein (HDL) subfractions and HDL-associated enzymes have not been determined in SCD patients. Blood was collected from 38 hemoglobin (Hb)A volunteers and 45 homozygous HbSS patients who had not received blood transfusions in the last 3 months. Serum lipids were measured by automated analyzer while LDL and HDL subfraction analysis was done by continuous disc polyacrylamide gel electrophoresis. Serum levels of cholesteryl ester transfer protein (CETP), lecithin-cholesterol acyltransferase (LCAT), apolipoprotein B (apoB) and apolipoprotein A-1 (apoA-I) were determined by enzyme-linked immunosorbent assay (ELISA). Total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) levels were significantly decreased, while TG levels were significantly increased in SCD patients compared to controls. A significant decrease in intermediate-density lipoprotein (IDL)-C, IDL-B, IDL-A and LDL-1 fractions were seen in SCD patients, while no significant difference was observed in small dense LDL particles. A significant decrease was seen in HDL-large, HDL-intermediate and HDL-small fractions in SCD patients versus controls. Levels of LCAT and ApoA-1 protein measured in SCD patients were significantly lower while no significant difference was observed in CETP and ApoB protein levels compared to controls. The reduction observed in LDL- and HDL-C in SCD patients was reflected as significantly decreased IDL, LDL-1 and HDL-subfractions. Decreased HDL subfractions may possibly lead to the reduced ApoA-1 and LCAT protein levels observed in SCD patients.     

A comprehensive study on mechanical properties of Bi1.8Pb0.4Sr2MnxCa2.2Cu3.0Oy superconductors

This study manifests the crucial change in the mechanical performances of Bi_1.8Pb_0.4Sr₂Mn_xCa_2.2Cu_3.0O_y superconductor samples (x = 0, 0.03, 0.06, 0.15, 0.3 and 0.6) prepared by conventional solid-state reaction method by use of Vickers microhardness (H_v) measurements carried out at different applied loads, (0.245 N ≤ F ≤ 2.940 N). Load dependent microhardness, load independent microhardness, Young’s (elastic) modulus and yield strength values being account for the potential technological and industrial applications are evaluated from the hardness curves and compared with each other. It is found that the H_v, elastic modulus and yield strength obtained decrease (increase) with the enhancement of the applied load for the undoped (doped) samples. Surprisingly, the results of the H_v values illustrate that the samples doped with x = 0.03, 0.06, 0.15, 0.3 and 0.6 exhibit reverse indentation size effect (RISE) feature whereas the pure sample obeys indentation size effect (ISE) behavior. Furthermore, the experimental results are examined with the aid of the available methods such as Meyer’s law, proportional sample resistance model (PSR), elastic/plastic deformation (EPD), Hays–Kendall (HK) approach and indentation-induced cracking (IIC) model. The results inferred show that the hardness values calculated by PSR and EPD models are far from the values of the plateau region, meaning that these models are not adequate approaches to determine the real microhardness value of the Mn doped Bi-2223 materials. On the other hand, the HK approach is completely successful for the explanation of the ISE nature for the pure sample while the IIC model is obtained to be the best model to describe the hardness values of the doped materials exhibiting the RISE behavior. Additionally, the bulk porosity analysis for the samples reveals that the porosity increases monotonously with the increment in the Mn inclusions inserted in the Bi-2223 system, presenting the degradation of the grain connectivity.     

Effect of Deep Cryogenic Treatment on Wear Resistance of AISI 52100 Bearing Steel

In this study, the effects of deep cryogenic treatment (DCT) on the wear resistance of AISI 52100 bearing steel were investigated. For this purpose, a number of bearing steel samples were held for different times (12, 24, 36, 48, 60 h) at deep cryogenic temperatures (?145 °C). The wear experiments were carried out in a ball–disk arrangement, by applying loads of 10 and 20 N and a sliding velocity of 0.15 m/s. After conducting the experimental studies, 36 h was found to be the optimal holding time. At this holding time, the wear rate and friction coefficient were decreased, while the hardness reached to maximum values. It was observed that DCT led to significant microstructural changes, which resulted in improved tribological properties.