Orthogonal cut of SPS-sintered composites with ferrous matrix and Fe Mo S particles: Numerical and experimental analysis

Metal-matrix composites with solid lubricant reinforcements may present a suitable alternative to improve the tribological behavior of sintered components. Besides the performance during the application, the presence of solid lubricants may also modify component manufacture, for example, during machining operations to achieve complex shapes not directly obtained from the sintering process. This work describes a numerical and experimental analysis on the orthogonal cut of metal-matrix composites composed of FeMoS particles embedded in an Astaloy 85 Mo (Höganäes AB) matrix. Specimens were prepared using the Spark-Plasma Sintering (SPS) technique, from mixtures containing powders of Astaloy 85 Mo steel and 2 wt% or 4 wt% of molybdenum disulfide (MoS2). An unreinforced Astaloy 85 Mo specimen (without MoS2) was also included in the analysis. Different microstructures were observed after SPS. The unreinforced specimen presented a ferrite-pearlite structure with a porosity level below 2% and the specimen sintered with 2 wt% of MoS2 presented iron sulfide particles dispersed in the steel matrix. The structure of the specimen sintered with 4 wt % was more complex, with two distinct phases dispersed in the Astaloy 85 Mo matrix. Experimental orthogonal cuts were conducted on the three specimens using a shaper machine tool equipped with a tungsten carbide (WCCo) cutting insert. Tests were recorded using a high-speed camera. The machined surfaces were later analyzed with an optical profilometer and in a scanning electron microscope (SEM) with energy-dispersive X-ray spectroscopy (EDS). The chips were also characterized. The cutting operation was simulated by two-dimensional (2D) finite-element analysis. The meshes were prepared based on the specimen microstructures and considering the properties of the individual phases. Results have indicated significant differences in the cutting process. Observation of the chip surfaces indicates plastic deformation on the unreinforced specimen, in opposition to more uniform scratches on the composite surfaces, especially that of the specimen sintered with 4 wt % of MoS2

CHASE-PL Climate Projection dataset over Poland – bias adjustment of EURO-CORDEX simulations

The CHASE-PL (Climate change impact assessment for selected sectors in Poland) Climate Projections – Gridded Daily Precipitation and Temperature dataset 5 km (CPLCP-GDPT5) consists of projected daily minimum and maximum air temperatures and precipitation totals of nine EURO-CORDEX regional climate model outputs bias corrected and downscaled to a 5 km  ×  5 km grid. Simulations of one historical period (1971–2000) and two future horizons (2021–2050 and 2071–2100) assuming two representative concentration pathways (RCP4.5 and RCP8.5) were produced. We used the quantile mapping method and corrected any systematic seasonal bias in these simulations before assessing the changes in annual and seasonal means of precipitation and temperature over Poland. Projected changes estimated from the multi-model ensemble mean showed that annual means of temperature are expected to increase steadily by 1 °C until 2021–2050 and by 2 °C until 2071–2100 assuming the RCP4.5 emission scenario. Assuming the RCP8.5 emission scenario, this can reach up to almost 4 °C by 2071–2100. Similarly to temperature, projected changes in regional annual means of precipitation are expected to increase by 6 to 10 % and by 8 to 16 % for the two future horizons and RCPs, respectively. Similarly, individual model simulations also exhibited warmer and wetter conditions on an annual scale, showing an intensification of the magnitude of the change at the end of the 21st century. The same applied for projected changes in seasonal means of temperature showing a higher winter warming rate by up to 0.5 °C compared to the other seasons. However, projected changes in seasonal means of precipitation by the individual models largely differ and are sometimes inconsistent, exhibiting spatial variations which depend on the selected season, location, future horizon, and RCP. The overall range of the 90 % confidence interval predicted by the ensemble of multi-model simulations was found to likely vary between −7 % (projected for summer assuming the RCP4.5 emission scenario) and +40 % (projected for winter assuming the RCP8.5 emission scenario) by the end of the 21st century. Finally, this high-resolution bias-corrected product can serve as a basis for climate change impact and adaptation studies for many sectors over Poland. The CPLCP-GDPT5 dataset is publicly available at http://dx.doi.org/10.4121/uuid:e940ec1a-71a0-449e-bbe3-29217f2ba31d

Improvement of regeneration in pepper: a recalcitrant species

[EN] Organogenesis is influenced by factors like genotype, type of explant, culture medium components, and incubation conditions. The influence of ethylene, which can be produced in the culture process, can also be a limiting factor in recalcitrant species like pepper. In this work, bud induction was achieved from cotyledons and hypocotyls-from eight pepper cultivars-on Murashige and Skoog (MS) medium supplemented with 22.2 mu M 6-benzyladenine (6BA) and 5.71 mu M indole-3-acetic acid (IAA), in media with or without silver nitrate (SN) (58.86 mu M), a suppressor of ethylene action. In the SN-supplemented medium, the frequencies of explants with buds and with callus formation were lower in both kinds of explant, but higher numbers of developed shoots were isolated from explants cultured on SN. Bud elongation was better in medium with gibberellic acid (GA(3)) (2.88 mu M) than in medium free of growth regulators or supplemented with 1-aminocyclopropane-1-carboxylic acid (ACC) at 34.5 mu M. However, isolation of shoots was difficult and few plants were recovered. The effect of adding SN following bud induction (at 7 d) and that of dark incubation (the first 7 d of culture) was also assessed in order to improve the previous results. When SN was added after bud induction, similar percentages of bud induction were found for cotyledons (average frequency 89.37% without SN and 94.37% with SN) whereas they doubled in hypocotyls (50% without SN and 87.7% with SN). In addition, in both kinds of explant, the number of developed plants able to be transferred to soil (developed and rooted) was greatly increased by SN. Dark incubation does not seem to improve organogenesis in pepper, and hypocotyl explants clearly represent a better explant choice-with respect to cotyledonary explants-for the pepper cultivars assayed.We thank the COMAV germplasm bank at Universitat Politecnica de Valencia and the Arid Lands Institute for pepper seeds and the Tunisian Ministry of Higher Education and Scientific Research who fund N. Gammoudi's stay.Gammoudi, N.; San Pedro-Galan, T.; Ferchichi, A.; Gisbert Domenech, MC. (2018). Improvement of regeneration in pepper: a recalcitrant species. In Vitro Cellular & Developmental Biology - Plant. 54(2):145-153. https://doi.org/10.1007/s11627-017-9838-1S145153542Ashrafuzzaman M, Hossain MM, Razi Ismail M, Shahidul Haque M, Shahidullah SM, Uz Zaman S (2009) Regeneration potential of seedling explants of chilli (Capsicum annuum). Afr J Biotechnol 8:591–596Bortesi L, Fischer R (2015) The CRISPR/Cas9 system for plant genome editing and beyond. Biotechnol Adv 33:41–52Brooks C, Nekrasov V, Lippman ZB, Van Eck J (2014) Efficient gene editing in tomato in the first generation using the clustered regularly interspaced short palindromic repeats/CRISPR-associated9 system. Plant Physiol 166:1292–1297Brown DC, Thorpe TA (1995) Crop improvement through tissue culture. World J Microbiol Biotechnol 11:409–415Carvalho MAF, Paiva R, Stein VC, Herrera RC, Porto JMP, Vargas DP, Alves E (2014) Induction and morpho-ultrastructural analysis of organogenic calli of a wild passion fruit. Braz Arch Biol Technol 57:581–859Christopher T, Rajam MV (1996) Effect of genotype, explant and medium on in vitro regeneration of red pepper. Plant CellTiss Org Cult 46:245–250Dabauza M, Peña L (2001) High efficiency organogenesis in sweet pepper (Capsicum annuum L.) tissues from different seedling explants. Plant Growth Regul 33:221–229De Filippis LF (2014) Crop improvement through tissue culture. In: Ahmad P, Wani MR, Azooz MM, Tran LSP (eds) Improvement of crops in the era of climate changes, vol 1. Springer, New York, pp 289–346Gammoudi N, Ben Yahia L, Lachiheb B, Ferchichi A (2016) Salt response in pepper (Capsicum annuum L.): components of photosynthesis inhibition, proline accumulation and K+/Na+ selectivity. JJ Aridland Agri 2:1–12González A, Arigita L, Majada J, Sánchez Tamés R (1997) Ethylene involvement in in vitro organogenesis and plant growth of Populus tremula L. Plant Growth Regul 22:1–6Grozeva S, Rodeva V, Todorova V (2012) In vitro shoot organogenesis in Bulgarian sweet pepper (Capsicum annuum L.) varieties. EJBio 8:39–44Gunay AL, Rao PS (1978) In vitro plant regeneration from hypocotyls and cotyledon explants of red pepper (Capsicum). Plant Sci Lett 11:365–372Huxter TJ, Thorpe TA, Reid DM (1981) Shoot initiation in light- and dark-grown tobacco callus: the role of ethylene. 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Global sensitivity analysis of stochastic computer models with joint metamodels

The global sensitivity analysis method used to quantify the influence of uncertain input variables on the variability in numerical model responses has already been applied to deterministic computer codes; deterministic means here that the same set of input variables gives always the same output value. This paper proposes a global sensitivity analysis methodology for stochastic computer codes, for which the result of each code run is itself random. The framework of the joint modeling of the mean and dispersion of heteroscedastic data is used. To deal with the complexity of computer experiment outputs, nonparametric joint models are discussed and a new Gaussian process-based joint model is proposed. The relevance of these models is analyzed based upon two case studies. Results show that the joint modeling approach yields accurate sensitivity index estimatiors even when heteroscedasticity is strong

An overview of burst, buckling, durability and corrosion analysis of lightweight FRP composite pipes and their applicability

© 2019 Elsevier Ltd. All rights reserved.The main aim of this review article was to address the performance of filament wound fibre reinforced polymer (FRP) composite pipes and their critical properties, such as burst, buckling, durability and corrosion. The importance of process parameters concerning merits and demerits of the manufacturing methods was discussed for the better-quality performance. Burst analysis revealed that the winding angle of ±55° was observed to be optimum with minimum failure mechanisms, such as matrix cracking, whitening, leakage and fracture. The reduction of buckling effect was reported in case of lower hoop stress value in the hoop to axial stress ratio against axial, compression and torsion. A significant improvement in energy absorption was observed in the hybrid composite pipes with the effect of thermal treatment. However, the varying winding angle in FRP pipe fabrication was reported as an influencing factor affecting all the aforementioned properties. Almost 90% of the reviewed studies was done using E-glass/epoxy materials for the composite pipe production. By overcoming associated limitations, such as replacing synthetic materials, designing new material combinations and cost-benefit analysis, the production cost of the lightweight FRP composite pipes can be decreased for the real-time applications.Peer reviewe

Erratum to: 36th International Symposium on Intensive Care and Emergency Medicine

[This corrects the article DOI: 10.1186/s13054-016-1208-6.]

Regional climate modeling for Asia

The regional climate model (RCM) with higher resolution and sophisticated physical processes can reproduce and project fine-scale climate information, which cannot be captured by the global climate model (GCM). Therefore, we developed the Seoul National University Regional Climate Model (SNURCM) in the 1990s to simulate the intrinsic and detailed climate prevailing in Asia. In this study, we reviewed the developmental processes of the SNURCM and its application researches. In the simulation of regional climate over Asia, systematic errors can be generated because of natural characteristics such as complex land-surface conditions and topography, warm ocean conditions, and strong seasonal monsoon circulation and convection. Numerous methods and techniques have been applied to reduce these errors and improve the SNURCM. For long-term simulations without climate drift, the spectral nudging technique as well as the traditional relaxation method was employed for the boundary conditions. To represent reasonable interactions between earth systems, a simple ocean model and an advanced land-surface model were implemented into the SNURCM. Physical schemes for precipitation and vertical diffusion developed for short-term numerical weather prediction models were optimized or improved for long-term simulation. The SNURCM has been applied to future climate projection, reproduction of extreme climate, and seasonal forecasting. Furthermore, the model has served as a part of the multi-model comparison program and an ensemble of international research programs