Narrow Results

The lifespan and performance of the industrial components used in aero engine’s and IC engines can be considerably increased by depositing thermal barrier coatings (TBCs). High-pressure gas turbines’ rotor blades and stator vanes are some of the world’s most heavily loaded engineering parts. In order to safeguard such components, more research is being conducted on TBCs, since the size of deployment and the production techniques used lead to improved life, economics, efficiency, and durability. This paper concentrates on the technological developments in the field of TBCs over the past few years in order to achieve maximum output. Current coating R&D has also placed an emphasis on the factors that contributed to the development of cutting-edge advanced coating-fabrication techniques, such as electron-beam physical vapor deposition (EB-PVD), suspension plasma spray (SPS), additive manufacturing (AM), functionally graded material (FGM) and incorporation of artificial intelligence (AI) in manufacturing of TBCs. This paper examines the current state of TBCs, including the most recent developments in terms of their performance and manufacturing, associated challenges, and suggestions for their potential usage in high temperature sector.

In this research paper, the comprehensive results on the double differential yield of ${\pi }^{\pm }$ and $k^{\pm }$ mesons, protons and antiprotons as a function of laboratory momentum are reported. These hadrons are produced in proton–carbon interaction at 60 GeV/c. EPOS 1.99, EPOS-LHC and QGSJETII-04 models are used to perform simulations. Comparing the predictions of these models show that QGSJETII-04 model predicts higher yields of all the hadrons in most of the cases at the peak of the distribution. In this interval, the EPOS 1.99 and EPOS-LHC produce similar results. In most of the cases at higher momentum of the hadrons, all the three models are in good agreement. For protons, all models are in good agreement. EPOS-LHC gives high yield of antiprotons at high momentum values as compared to the other two models. EPOS-LHC gives higher prediction at the peak value for ${\pi }^{+}$ mesons and protons at higher polar angle intervals of $100<𝜃<420$ and $100<𝜃<360$, respectively, and EPOS 1.99 gives higher prediction at the peak value for ${\pi }^{-}$ mesons for $140<𝜃<420$. The model predictions, except for antiprotons, are compared with the data obtained by the NA61/SHINE experiment at 31 GeV/c proton–carbon collision, which clearly shows that the behavior of the distributions in models are similar to the ones from the data but the yield in data is low because of lower beam energy.

In this research paper, comprehensive results on the double differential yield of ${\pi }^{\pm }$ and $K^{\pm }$ mesons, protons and antiprotons as a function of laboratory momentum in several polar angle ranges from 0–420 mrad for pions, 0–360 mrad for kaons, proton and antiproton are reported. EPOS 1.99, EPOS-LHC and QGSJETII-04 models are used to perform simulations. The predictions of these models at 90 GeV/c are plotted for comparison, which shows that QGSJETII-04 model gives overall higher yield for ${\pi }^{+}$ mesons in the polar angle interval of 0–40 mrad but for the ${\pi }^{-}$ the yield is higher only up to 20 mrad. For ${\pi }^{+}$ mesons after 40 mrad, EPOS-LHC predicts higher yield as compared to EPOS 1.99 and QGSJETII-04 while EPOS-LHC and EPOS 1.99 give similar behavior in these two intervals. However, for ${\pi }^{-}$ mesons EPOS-LHC and EPOS 1.99 give similar behavior in these two intervals. For of $K^{\pm }$ mesons, QGSJETII-04 model gives higher predictions in all cases from 0–300 mrad, while EPOS 1.99 and EPOS-LHC show similar distributions. In case of protons, all models give similar distribution but this is not true for antiproton. All models are in good agreement for p$>$ 20 GeV/c. EPOS 1.99 produce lower yield compared to the other two models from 60–360 mrad polar angle interval.

In this work, we investigate the production of ${\pi }^{\pm }$, $K^{\pm }$ mesons, protons and antiprotons, by exploiting the theoretical hadron production models: EPOS 1.99, EPOS-LHC and QGSJETII-04, using proton–carbon collisions at a potential laboratory momentum of 158 GeV/c. Laboratory momentum-dependent double differential yields of these particles are studied where it is produced at a polar angle ranging from 0 mrad to 420 mrad for ${\pi }^{\pm }$ mesons while for $K^{\pm }$ mesons, protons and antiprotons, the angle ranges from 0 mrad to 360 mrad. The QGSJET predicts high yields of the ${\pi }^{\pm }$ mesons for a polar angle ranging from 0 mrad to 20 mrad at the peak of the distribution while beyond 20 mrad, the high yield is demonstrated by EPOS-LHC. In the case of $K^{\pm }$ mesons and antiprotons, the QGSJETII-04 gives higher yield at the peak of the distribution in all the cases, whereas the EPOS-1.99 and EPOS-LHC produce similar results. In most of the cases at high momentum of the hadrons, the trios are in very good agreement with each other.

The yield of $\mathrm{\Upsilon }$ associated with open charm has been estimated with different approaches. The crucial differences between SPS and DPS predictions are discussed.

Projects proposed for the long baseline neutrino and cosmic rays’ experiments require high precision hadron production measurements, using proton beam on different targets, to achieve their physics goals. The predictions of neutrino beam depend on the modeling of protons interacting within the targets. Thus, different hadronic models are being used for this purpose with different precisions, which depend on the projectile protons energy and material of the target used. The comparison of different hadron production models predictions, in proton–carbon interactions at 31 GeV/c, is reported in this paper. Double differential yield of ${\pi }^{\pm }$, $K^{\pm }$ mesons, protons and antiprotons in several polar angle ranges is presented as a function of laboratory momentum. EPOS1.99, EPOS-LHC and QGSJETII-04 models are used to perform simulations. The results of the simulated data are compared with hadron production measurements in proton–carbon interactions at 31 GeV/c performed by the NA61/SHINE experiment at the SPS CERN [Eur. Phys. J. C76, 84 (2016)]. None of the models completely describes all the distributions. In most of the cases, EPOS1.99 describes the experimental data very well. EPOS-LHC results are also similar in some cases, but QGSJETII-04 predictions failed to reproduce the experimental data.

The pure iron and aluminum powders were milled with 3wt.% and 7wt.% of alumina nanoparticles in planetary ball mill in order to produce iron aluminide by mechanical alloying technique. The resulting powder mixture was sintered after the formation of iron aluminide by spark plasma sintering (SPS) method to achieve specimens with the highest densification. SPS technique was utilized on specimens under the condition of 40MPa pressure at 950^∘C for 5min. The microstructures were analyzed after sintering using scanning electron microscopy and EDS analysis. The results indicated that the aluminide iron phase has been produced at high purity. The sintered specimens were treated under hardness and density tests, and it was characterized that the specimen included 3wt.% of alumina nanoparticles had the highest microhardness. Likewise, it was revealed that the unreinforced sample had a maximum relative density. The wear behavior of specimens was performed at 600^∘C. The results of weight loss showed after 1000m of wear test, the weight loss of unreinforced specimen was reduced up to 0.21g while the specimen with 3wt.% of alumina nanoparticle indicated the lowest weight loss about 0.02g. The worn surfaces were evaluated by scanning electron microscopy which indicated that the main wear mechanism at high temperature included adhesive wear and delamination.

Two series of porphyrin liquid crystalline compounds, meso-tetra-[(p-alkacyloxy-m-ethyloxy)phenyl]porphyrin (TPAMEP), and [5-(p-alkacyloxy) phenyl-10,15,20-tri-phenyl] porphyrin (APTPP) are synthesized and display a hexagonal columnar discotic columnar (Col_h) phase. Their structure and properties were studied by elemental analysis, molar conductance, UV-visible and infrared spectra. Luminescence spectra of the compounds were discussed. Quantum yields of the Q band are in the region 0.007935-0.05847. The electrochemical studies show that the redox potentials do not change with the variation of the chain length. The surface photovoltage (SPV) response of the compounds was investigated by means of surface photovoltage spectroscopy (SPS) and field-induced surface photovoltage spectroscopy (FISPS), and the bands are analogous with the UV-visible absorption spectra.

Simon van der Meer was a brilliant scientist and a true giant of accelerator science. His seminal contributions to accelerator science have been essential to this day in our quest for satisfying the demands of modern particle physics. Whether we talk of long base-line neutrino physics or antiproton–proton physics at Fermilab or proton–proton physics at LHC, his techniques and inventions have been a vital part of the modern day successes. Simon van der Meer and Carlo Rubbia were the first CERN scientists to become Nobel laureates in Physics, in 1984. Van der Meer's lesser-known contributions spanned a whole range of subjects in accelerator science, from magnet design to power supply design, beam measurements, slow beam extraction, sophisticated programs and controls.

By any standards, John Adams had a most remarkable career. He was involved in three important, emerging technologies, radar, particle accelerators and controlled fusion, and had an outstanding impact on the last two. Without a university education, he attained hierarchical positions of the highest level in prestigious national and international organizations. This article covers the CERN part of his career, by offering some personal insights into the different facets of his contributions to major accelerator projects, from the first strong-focusing synchrotron, the PS, to the SPS and its conversion to a proton–antiproton collider. In particular, it outlines his abilities as a leader of an international collaboration, which has served as an example for international initiatives in other disciplines.

We assess the literature on public and private quality standards and their impact in food markets, international trade, and global supply chains. We focus on their effects on welfare, trade, industrial organization, and labor markets and with special attention to the North-South context. We also attempt to better characterize when these measures constitute protectionism, a complicated task. We look at studies investigating public and private standards and across various quantitative approaches and countries. These standards have complex effects. The evidence is mixed regarding standards as catalyst for or as impediment against trade and development, reflecting the complexity of these effects and their specificity to industries and countries. The analysis of standard-like non-tariff measures and their impacts does not lead to sweeping prescriptions for policy reforms. We identify more modest prescriptions and make some recommendations for fruitful research directions.

A meta-analysis explains the variation in estimated trade effects of technical barriers to trade broadly defined, using available estimates from the empirical international trade literature, and accounting for data sampling and methodology differences. Agriculture and food industries tend to be more impeded by these barriers than other sectors. SPS regulations on agricultural and food trade flows from developing exporters to high-income importers tend to impede trade. Not controlling for “multilateral resistance” barriers increase the likelihood to overstate the trade impeding effect of technical measures and not accounting for their potential endogeneity with trade does the opposite. Studies using direct maximum residue limits tend to find more trade impeding effects than other measures and clearer policy implications. Other technical measures proxies tend to muddle results and increase the likelihood of inconclusive results and few policy implications.

The price-wedge method yields a tariff-equivalent estimate of technical barriers to trade (TBT). An extension of this method accounts for imperfect substitution between domestic and imported goods and incorporates recent findings on trade costs. We explore the sensitivity of this revamped TBT estimate to its key determinants (substitution elasticity, preference for home good, and trade cost). We use the augmented approach to investigate the recent Japan-U.S. apple trade dispute and find that removing the Japanese TBT would yield limited export gains to the United States. We then draw policy implications of our findings.

The expansion of the U.S. corn seed trade is not well understood. This article econometrically investigates world demand for U.S. corn seeds, focusing on trade costs impeding exports, including transportation, tariffs, and sanitary and phytosanitary (SPS) regulations. The analysis estimates a derived demand for seed by foreign corn producers using data from 48 countries for the years 1989 to 2004. An SPS count variable captures shifts in the cost of seeds faced by foreign users. A sample selection framework accounts for the large presence of zero trade flows. All trade costs have a significantly negative impact on U.S. com seed exports.

Simon van der Meer was a brilliant scientist and a true giant of accelerator science. His seminal contributions to accelerator science have been essential to this day in our quest for satisfying the demands of modern particle physics. Whether we talk of long base-line neutrino physics or antiproton–proton physics at Fermilab or proton–proton physics at LHC, his techniques and inventions have been a vital part of the modern day successes. Simon van der Meer and Carlo Rubbia were the first CERN scientists to become Nobel laureates in Physics, in 1984. Van der Meer’s lesserknown contributions spanned a whole range of subjects in accelerator science, from magnet design to power supply design, beam measurements, slow beam extraction, sophisticated programs and controls.

By any standards, John Adams had a most remarkable career. He was involved in three important, emerging technologies, radar, particle accelerators and controlled fusion, and had an outstanding impact on the last two. Without a university education, he attained hierarchical positions of the highest level in prestigious national and international organizations. This article covers the CERN part of his career, by offering some personal insights into the different facets of his contributions to major accelerator projects, from the first strong-focusing synchrotron, the PS, to the SPS and its conversion to a proton—antiproton collider. In particular, it outlines his abilities as a leader of an international collaboration, which has served as an example for international initiatives in other disciplines.