A high-throughput method for the fabrication of ordered arrays of Au nanoparticles is presented. It is based on pulsed electrodeposition into porous anodic alumina templates. In contrast to many synthesis routes, it is cyanide-free, prior separation of the alumina template from the aluminium substrate is not required, and the use of contaminating surfactants/capping agents often found in colloidal synthesis is avoided. The aspect ratio of the nanoparticles can also be tuned by selecting an appropriate electrodeposition time. We show how to fabricate arrays of nanoparticles, both with branched bases and with hemispherical bases. Furthermore, we compare the different morphologies produced with electron microscopies and grazing-incidence synchrotron X-ray diffraction. We find the nanoparticles are polycrystalline in nature and are compressively strained perpendicular to the direction of growth, and expansively strained along the direction of growth. We discuss how this can produce dislocations and twinning defects that could be beneficial for catalysis.

This paper documents the seventeenth data release (DR17) from the Sloan Digital Sky Surveys; the fifth and final release from the fourth phase (SDSS-IV). DR17 contains the complete release of the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey, which reached its goal of surveying over 10,000 nearby galaxies. The complete release of the MaNGA Stellar Library accompanies this data, providing observations of almost 30,000 stars through the MaNGA instrument during bright time. DR17 also contains the complete release of the Apache Point Observatory Galactic Evolution Experiment 2 survey that publicly releases infrared spectra of over 650,000 stars. The main sample from the Extended Baryon Oscillation Spectroscopic Survey (eBOSS), as well as the subsurvey Time Domain Spectroscopic Survey data were fully released in DR16. New single-fiber optical spectroscopy released in DR17 is from the SPectroscipic IDentification of ERosita Survey subsurvey and the eBOSS-RM program. Along with the primary data sets, DR17 includes 25 new or updated value-added catalogs. This paper concludes the release of SDSS-IV survey data. SDSS continues into its fifth phase with observations already underway for the Milky Way Mapper, Local Volume Mapper, and Black Hole Mapper surveys.

Studies of parity (P) and time-reversal (T) symmetry violations using molecules are important and attractive because they are complementary to the high-energy tests of physics beyond the Standard Model of elementary particles. The focus of our present work is to surpass the current accuracies of the quantity X, an enhancement factor for the nuclear Schiff moment (Q), and the nucleon electric dipole moments for the (TlF)-Tl-205 molecule. We obtain X = 6856 a.u. using a relativistic coupled-cluster singles and doubles and perturbative triples (CCSD(T)) approach. This new value of X improves the upper limits for Q and the proton EDM by about ten percent over the previous ones. [GRAPHICS] .

Betong är ledande byggnadsmaterial med många goda egenskaper men också förhållandevisstora koldioxidutsläpp. Cementtillverkningen står idag för fem procent av världens utsläpp avväxthusgaser. Betongbyggandet måste ständigt förbättra sin hållbarhet och ta till sig åtgärderför att minska klimatpåverkan. Boverket har ställt ett krav att nybyggnationer måste klimatdeklareras som en vägledning mot mer hållbart byggande. Denna studie syftar till att undersöka och använda en modellbaserad LCA-analys där klimatförbättrad betong ställs mot en traditionell betong. Detta utfördes genom att en befintlig BIM modell av en fastighet på Kapellvägen undersöktes. Miljöpåverkans förbättringsmöjlighet besvaras genom att ta fram koldioxidutsläpp ekvivalentför betong i denna fastighet och jämföra det mot koldioxidutsläpp ekvivalent för enklimatförbättrad betong för att visa en potentialkoldioxid besparing. En kvantitativ metod väljs för denna studie, genom användning av LCA bedömning. LCA bedömningen utförs med hjälp av flera datorbaserade BIM program för att kunna ta fram simuleringar och beräkningar. Dessa BIM program är Autodesk Revit, Autodesk Insight, Bidcon och Solibri. En referensbyggnad som representerar ett vanligt flerbostadshus i Sverige ligger till grunden av bedömningen. LCA görs utifrån endast koldioxidutsläppmiljöindikator. Livscykelbedömningen för de två betongsorterna omfattar byggskedet och dess moduler A1-A5 samt modulen B6 driftsenergi som ingår i användningsskedet enligt svensk standard SS-EN 15978:2011. För energiförbrukning (kWh/BTA) i referensbyggnaden som motsvarar driftsenergi B6, tas det hänsyn endast till klimatskärmen. Inga hänsyn tas till eventuella skillnader i hållfasthet-, brand- ochljudklasser vid utbyte av material. LCC begränsas till nyttokalkyl.Resultat visar att den totala klimatpåverkan från stommen med traditionell betong beräknas till161 tonCO₂e för flerbostadshuset i Kapellvägen 11. Medan den totala klimatpåverkan frånstommen med klimatförbättrad betong beräknas till 104 tonCO₂e. Totala priset ökar med cirka 49 tusen kronor om man ersätter den traditionella betongen med en klimatförbättrad variant.Materialbytet i betongstommen leder till minskning av koldioxidutsläpp med cirka 57 ton CO₂e. Koldioxidutsläppbesparingen motsvarar en kostnad på 0,86 kr/kgCO2e. Investeringen i den klimatförbättrade betongen motsvarar cirka 0,34% av den totala grundinvesteringen, medan koldioxidutsläppet är 13,3% mindre för hela byggnaden. På långsikt om 100 år ökar nuvärdet av investeringen i materialbytet med ca 222%. Driftskostnad förblir densamma innan och eftermaterialets byte. Klimatpåverkans förbättringar är möjliga och målet på färdplanen 2045 kan nås om alla i bygg- och anläggningssektor samarbetar. Minskning i klimatpåverkan för betongen gör att byggmaterialet blir mer hållbart i framtiden och hjälper delvis i färdplanen 2045 för en klimatneutral bygg- och anläggningssektor. Tanken är att få fler aktörer till en konkurrens om vem som har minst klimatavtryck på deras klimatförbättrade betong. Klimatförbättrad betong har idag begränsningar inom exponerings och hållfasthetsklasser, men mycket betong används inomhus med låga laster och exponeringsklasser som klimatförbättrad betong förser.

This paper documents the 16th data release (DR16) from the Sloan Digital Sky Surveys (SDSS), the fourth and penultimate from the fourth phase (SDSS-IV). This is the first release of data from the Southern Hemisphere survey of the Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2); new data from APOGEE-2 North are also included. DR16 is also notable as the final data release for the main cosmological program of the Extended Baryon Oscillation Spectroscopic Survey (eBOSS), and all raw and reduced spectra from that project are released here. DR16 also includes all the data from the Time Domain Spectroscopic Survey and new data from the SPectroscopic IDentification of ERosita Survey programs, both of which were co-observed on eBOSS plates. DR16 has no new data from the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey (or the MaNGA Stellar Library "MaStar"). We also preview future SDSS-V operations (due to start in 2020), and summarize plans for the final SDSS-IV data release (DR17).

High energy surface x-ray diffraction (HESXRD), x-ray reflectivity (XRR), mass spectrometry (MS) and surface optical reflectance (SOR) have been combined to simultaneously obtain sub-second information on the surface structure and morphology from a Pd(100) model catalyst during in situ oxidation at elevated temperatures and pressures resulting in Pd bulk oxide formation. The results show a strong correlation between the HESXRD and SOR signal intensities during the experiment, enabling phase determination and a time-resolved thickness estimation of the oxide by HESXRD, complemented by XRR measurements. The experiments show a remarkable sensitivity of the SOR to changes in the surface phase and morphology, in particular to the initial stages of oxidation/reduction. The data imply that SOR can detect the formation of an ultrathin PdO surface oxide layer of only 2-3 angstrom thickness.

The oxidation and reduction of an Ir(100) surface using 2.5, 5, and 10 mbar O₂ partial pressure and a sample temperature of 775 K have been studied by using high-energy surface X-ray diffraction (HESXRD) which allowed to record large volumes of reciprocal space in short time periods. The complex 3D diffraction patterns could be disentangled in a stepwise procedure. For the 2.5mbar experiment the measurements indicate the formation of an Ir(100)-O c(2 × 2) oxygen superstructure along with the onset of epitaxial IrO₂(110) bulk oxide formation. For the 5 and 10 mbar O₂ partial pressures the formation of additional IrO₂ bulk oxide epitaxies with (100) and (101) orientations as well as of polycrystalline IrO₂ was observed. Upon CO reduction, we found the IrO₂ islands to be reduced into epitaxial and metallic Ir(111) and (221) oriented islands.

Detta examensarbete presenterar en teoretisk undersökning av energin och stabiliteten hos gränssnitt i järnkarbidföreningar och fokuserar specifikt på α-Fe/Cr₇C₃-systemet. Studien syftar till att fylla kunskaps tomrummet gällande ytegenskaperna hos dessa gränssnitt genom användning av densitetsfunktionalteori (DFT). Sex olika α-Fe/Cr₇C₃-gränssnitt konstruerades α-Fe(001)/Cr₇C₃(024), α-Fe(001)/Cr₇C₃(202), α-Fe(001)/Cr₇C₃(040), α-Fe(110)/Cr₇C₃(024), α-Fe(110)/Cr₇C₃(202) och α-Fe(110)/Cr₇C₃(040). På grund av begränsade beräkningsresurser analyserades endast ett av dem för att bestämma dess gränssnittsenergivärde. Resultaten visade att gränssnittsenergin för α-Fe(001)/Cr₇C₃(040)- gränssnittet ligger inom intervallet för inkoherenta gränssnitt, vilket indikerar dess stabilitet. De beräknade gränssnittsenergivärdena varierade mellan 0,94 och 3,39 J/m² , vilket är i linje med liknande studier där järngränssnitt studeras. Minimi och lokala minimipunkter i gränssnittets energikurva, vilket representerar stabila konfigurationer vid specifika avstånd mellan gränssnittet. Förekomsten av en minimipunkt vid ett gränssnittsavstånd på d = 1,35 Å med en gränssnittsenergi på 0,94 J/m² indikerar den mest stabila konfigurationen, medan en lokal minimipunkt vid d = 2,27 Å med en gränssnittsenergi på 2,12 J/m² antyder en annan stabil konfiguration för gränssnittet. Slutsatsen dras att beräkningarna utfördes korrekt med ett gränssnittsenergivärde på 0,94 J/m² för den mest stabila konfigurationen vid en supercellslängd (a_Supercell) på 22,23 Å. Fynden från denna forskning har betydande implikationer för framtida undersökningar och tillämpningar. För det första fyller denna studie kunskapsgapet gällande de otillräckligt utforskade ferrit-karbidgränssnitten med teoretisk data. För det andra bidrar den erhållna kunskapen från studiet av dessa gränssnitt till förståelsen av väteinteraktioner, vilket är grundläggande för övergången till en väteekonomi. Dessutom innebär gränssnittets inkoherenta natur utmaningar när det gäller att förstå materialbeteende och egenskaper, vilket kräver ytterligare undersökningar för att utforma effektiva system. Framtida arbete inkluderar experimentell validering av gränssnittet mellan α-Fe/Cr₇C₃ för att jämföra teoretiska och experimentella energier och stabilitet. Att undersöka återstående gränssnitt och undersöka effekterna av att introducera väteatomer i dessa gränssnitt och beräkna motsvarande vätefällningsenergier är viktiga forskningsområden. Gränssnittsdesign, flerskalig modellering och studier av andra järnkarbid-system kan ytterligare främja förståelsen av dessa gränssnitt.

Dagens hantverkare har fler verktyg och redskap till sitt förfogande än någonsin förr. För att utföra sitt arbete är hantverkare beroende av sina verktyg och materiel och måste därför alltid ha tillgång till dem. Byxväskor till hantverkare finns i olika slag som ett komplement till fickor på arbetskläder. En variant producerats av Cirk-L men dessa saknar en förvaringslösning för smidig transport. Deras byxväskor är ämnade till att bytas vid behov av olika verktyg och material. Problemet är att det inte finns ett system att förvara byxväskorna och dess innehåll när de inte brukas på arbetsplatser. Syftet med arbetet är att utveckla en lösning som gör det möjligt att smidigt transportera Cirk-Ls byxväskor. Målet är att utveckla en prototyp av en förvaringslösning genom en konceptutvecklingsprocess, materialval, CAD-modellering med detaljritningar samt finita element-analys för hållfasthetsberäkningar.Förvaringslösningen kan bära sex stycken byxväskor utvändigt och diverse verktyg invändigt. Beräkningar utförs med hjälp av MATLAB tillägget CALFEM och simuleras i Creo för att dimensioneras. Materialval för samtliga komponenter utförs med hänsyn till hållbarhet ur ett miljöperspektiv. Processen resulterar i en prototyp som uppfyller de krav och önskemål som formulerats. Förvaringslösningen kan bära sex stycken byxväskor utvändigt och diverse verktyg invändigt.

Digitalization has the potential to radically change the way buildings are designed, produced, and operated. In this digital transformation, the establishment of information standards play an important role. However, despite substantial efforts in the development of both technology and standards, these are not yet fully adopted in construction. This study aims to review the adoption of standards and to examine whether suppliers of prefabricated concrete elements have transformed their business models. The purpose is to strengthen the understanding of the interplay between the adoption of standards and business model renewal. Driving forces for the adoption of standards are identified and coupled with suppliers' arguments for business model protection and renewal, explained in terms of a market and a hierarchy approach. The market approach embraces the adoption of open standards for improved competition and information exchange along with the further adoption of industrialized construction. This study identifies that common standards for precast elements are lacking, which leads to waste in terms of structural re-design and liability uncertainties. On the other hand, a market situation with open standards is challenging for suppliers to utilize and benefit from their existing operational platforms. Suppliers of precast elements strive for a hierarchy approach, that is, the adoption of the whole value chain, to protect their market position and continue offering structural frameworks and services. This concurs with arguments for industrialized construction, which emphasize the benefits of continuous improvements. This study contributes to the understanding of drivers and impediments for the up-take of standards versus business model renewal in construction.

Digitalization transforms the design, construction and operation of buildings and brings promises of integrated information exchange, ease of communication and productivity improvements for the whole construction sector. These promises depend significantly on the establishment of common information standards, i.e. rules and classification of information. However, despite rigorous efforts on development of standards and considerable technology advancements, standards are not yet fully adopted in construction and benefits from digitalization are not fully capitalized. The objective of this study is to review the adoption of standards and business model renewal for industrialized suppliers of precast concrete elements, with the purpose of reaching enhanced understanding of the mechanisms of standards adoption and business model renewal. The study identifies driving forces for adoption of standards that counteract with arguments for business renewal, explained in terms of a market versus a hierarchy approach in this context. The market approach promotes adoption of open standards for enhanced competition, ease of communication and information exchange as well as improved utilization of industrialized construction. The existing lack of common standards for precast elements, identified in this study, render e.g. waste due to structural re-design and liability uncertainties. However, on a market with open standards, the precast suppliers find it difficult to fully utilize and benefit from their existing operational platforms. Precast supplier search for adoption of the whole value chain of precast structural frameworks, i.e. a hierarchy approach, to protect their market position and maintain their business offerings of complete structural frameworks that include design, manufacturing, logistical services as well as on-site assembly. The integrated hierarchy approach concurs with arguments for industrialized construction, i.e. collecting experiences from design, manufacturing, logistics and assembly as a basis for continuous improvements. The study thus contributes to the understanding of drivers and impediments for adoption of standards versus business renewal in construction.

The shipbuilding, automotive and aerospace industries are examples of industries offering product service systems (PSS) to their customers, i.e. they combine physical products with services to add increased value. While product service systems are well established in many manufacturing industries, it has barley emerged in construction, which is mainly explained by the well-established project-based organisation of construction work. Thus, implementation of product and service systems in construction will challenge the established utilisation of technical solutions and systems, production processes and supply chains. The objective of this study is to identify and critically review examples of product service systems in construction supply chains, with the purpose of describing how it challenges prevailing business systems and organisation of construction work. The study rests upon empirical data collected in two case studies at Gyproc Saint-Gobain in Denmark and Celsa Steel Service in Sweden. The two case studies reveal significant challenges related to the implementation and marketing processes of product service systems. Companies that develop and expand their business offers by providing new product service systems find themselves operating in two parallel market segments, i.e. the traditional market of construction components and the new market of product service systems. The product service systems reviewed in the two case studies show a strong focus and emphasis on the development of the offer and the operational platform, while the companies’ roles and market positions remain unchanged. Thus, the case study companies organise and operate their businesses and market relations as before the implementation of the product service system. The conclusion is that development and implementation of product service systems in construction supply chains, even at the low end of product complexity represented by single building components, require awareness in the companies’ offer of products and services, development in operational platforms as well as clear market position.

The shipbuilding, automotive and aerospace industries are examples of industries offering product service systems (PSS) to their customers, i.e. they combine physical products with services to add increased value. While product service systems are well established in many manufacturing industries, it has barely emerged in the fragmented and project-based organisation of construction. The objective of this study is to identify and critically review examples of product service systems in construction supply chains, with the purpose of describing how it challenges prevailing business systems and organisation of construction work. The study rests upon two case studies carried out at Gyproc Saint-Gobain in Denmark and Celsa Steel Service in Sweden. The findings reveal significant challenges related to the implementation and marketing of the product service systems provided. Companies that develop and expand their business offers by providing new product service systems tend to find themselves operating in two parallel market segments, i.e. the traditional market of construction components and the new market of product service systems. The PSS-offers reviewed in the case studies show a strong focus and emphasis on the development of the offer and the operational platform, while the companies’ market positions remain unchanged. Thus, the case study companies organise and operate their businesses and market relations as before the implementation of the product service system. The conclusion is that development and implementation of product service systems in construction supply chains requires awareness in the companies’ offer of products and services, well-established operational platforms, and particularly, a renewed market position.

Multiconfiguration Hartree-Fock (MCHF) and multiconfiguration Dirac-Hartree-Fock (MCDHF) calculations are performed for the 2p(5) P-2 degrees, 2p(4)(P-3)3s P-4, 2p(4)(P-3)3s P-2, and 2p(4)(P-3)3 p S-4 degrees states of F-19 I to determine their hyperfine constants. Several computing strategies are considered to investigate electron correlation and relativistic effects. High-order correlation contributions are included in MCHF calculations based on single and double multireference expansions. The largest components of the single reference MCHF wave functions are selected to define the multireference (MR) sets. In this scheme, relativistic corrections are evaluated in the Breit-Pauli approximation. A similar strategy is used for the calculation of MCDHF relativistic wave functions and hyperfine parameters. While correlation and relativistic corrections are found to be rather small for the ground state, we highlight large relativistic effects on the hyperfine constant A(3/2) of 2p(4)(P-3)3 p(4)S(degrees) and, to a lesser extent, on A(1/2) of 2p(4)(P-3)3s P-4. As expected for such a light system, electron correlation effects dominate over relativity in the calculation of the hyperfine interaction of all other levels considered. We also revisit the hyperfine constants of 2p(3)((4)(S))3s S-5 degrees and 2p(3)(S-4)3 p P-5 in O-17 using similar strategies. The results are found to be in excellent agreement with experiment.

The numerical simulation of the induction heating process can be computationally expensive, especially if ferromagnetic materials are studied. There are several analytical models that describe the electromagnetic phenomena. However, these are very limited by the geometry of the coil and the workpiece. Thus, the usual method for computing more complex systems is to use the finite element method to solve the set of equations in the multiphysical system, but this easily becomes very time consuming. This paper deals with the problem of solving a coupled electromagnetic - thermal problem with higher computational efficiency. For this purpose, a semi-analytical modeling strategy is proposed, that is based on an initial finite element computation, followed by the use of analytical electromagnetic equations to solve the coupled electromagnetic-thermal problem. The usage of the simplified model is restricted to simple geometrical features such as flat or curved surfaces with great curvature to skin depth ratio. Numerical and experimental validation of the model show an average error between 0.9% and 4.1% in the prediction of the temperature evolution, reaching a greater accuracy than other analyzed commercial softwares. A 3D case of a double-row large size ball bearing is also presented, fully validating the proposed approach in terms of computational time and accuracy for complex industrial cases.

Rolling contact fatigue is a unique mode of fatigue that components under cyclic contact loading experience. In this work, the impact of induction hardening residual stresses in rolling contact fatigue lifetime is investigated experimentally and numerically using the Dang Van multiaxial criterion. Various residual stress fields from induction hardening are simulated using the finite element method and are mapped into a classical monocontact finite element model. The impact of induction hardened residual stresses on the lifetime of a component has been investigated, and the importance of incorporating the residual stress profile into fatigue life assessments is affirmed.

The usage of induction hardening in the industry has increased in the last years due to its efficiency and repeatability. Induction hardening produces a hard martensitic layer on the specimen surface, which is accompanied by the generation of compressive residual stresses in the hardened case and tensile stresses in the untreated core. Residual stresses generated by induction hardening greatly impact on fatigue performance, as they act as crack growth retardants. In this work, a multiphysical coupled finite element model is developed to simulate induction hardening and compute the final residual stress state of the specimens along the microstructural transformations and hardness evolution. The impact of the transformation induced plasticity strain in the stress-state of the specimen during the process is also studied. The experimental validation shows that considering the transformation induced plasticity in induction hardening simulations improves the residual stress predictions, concluding that this effect should be included to achieve good residual stress predictions, especially in the subsurface region.

Induction hardening is widely used in the industry as a surface heat treatment that improves the surface and the subsurface hardness of components greatly. The hardened case, which usually is a few mm, highly impacts the surface and structural integrity of the component. In this work, we simulate the scanning induction hardening process by means of finite element modeling. The computed hardness, microstructure, and residual stress profile are compared with experimentally measured data using several surface and subsurface characterization techniques. A very good agreement is found between the simulated and experimentally measured residual stresses, which were characterized by the incremental hole drilling technique.

Induction hardening has the potential to produce favorable surface integrity that can improve fatigue performance and extend the lifetime of a component. The localized superficial heating provided by induction is the main advantage of this process, as it allows the core to remain intact and, therefore, ductile, while the surface is hardened. Achieving favorable characteristics in the hardened case is of great importance, as this process is usually applied to load bearing and wear-susceptible metallic components. The simulation of the hardening process by induction heating is a complex and challenging task at which many efforts have been directed in the last years. Due to the numerous interactions of the many physics that take part in the process (electromagnetic, thermal, microstructural and mechanical), a highly coupled finite element model is required for its numerical simulation. In this work, a semi-analytical induction heating model is used to compute the induction hardening process, predicting the size and shape of the hardened layer and the distribution of the hardness. Using the semi-analytical model allows the computational time to be much faster compared to a fully coupled model using a commercial software, where the time consumption for the presented 2D case is reduced by 20 %. Experimental validation is presented for cylindrical 42CrMo4 billets heated by a short solenoidal inductor, which shows good agreement with the predicted results, reaching an average error of 3.2 % in temperature estimations.

A first-order asymptotic analysis of the Griffith energy balance in the Johnson-Kendall-Roberts model of adhesive contact under non-symmetric perturbation of the contact geometry is presented. The pull-off force is evaluated in explicit form. A particular case of adhesive contact between a relatively stiff sphere and an elastic half-space is considered under the assumption that the sphere geometry is changed by the application of an arbitrary lateral normal surface loading. The effect of the sphere Poisson's ratio on controlling the adhesive pull-off force is considered.

This article is part of a discussion meeting issue 'A cracking approach to inventing new tough materials: fracture stranger than friction'.

In recent years, the method of dimensionality reduction (DR) has started to figure as a very convenient tool for dealing with a wide class of elastic contact problems. The MDR modeling framework introduces an equivalent punch profile and a one-dimensional Winkler-type elastic foundation, called henceforth Popov's foundation. While the former mainly accounts for the geometry of contact configuration, the Popov foundation inherits the main characteristics of both the contact interface (like friction and adhesion) and the contacting elastic bodies (e.g., anisotropy, viscoelasticity or inhomogeneity). The discussion is illustrated with an example of the Kendall-type adhesive contact for an isotropic elastic half-space.

A vanishing at infinity solution of the three-dimensional Laplace equation is sought in an a priori unknown domain with overdetermined boundary conditions, the right-hand sides of which depend on the unit normal to the free boundary. A perturbation analysis of the nonstandard free boundary problem that models deep abrasive drilling has been performed under the assumption that the free boundary is close to the surface of a given semi-infinite cylinder, the longitudinal position of which depends on the boundary data, and the leading-order asymptotic solution has been developed.

Unilateral adhesive contact between a rigid indenter and a uniformly stretched membrane of arbitrary shape is considered. The generalized Johnson-Kendall-Roberts (JKR)-type and Derjaguin- Muller-Toporov (DMT)-type models of non-axisymmetric adhesive contact are presented for short- and long-range adhesion, respectively, and the JKR-DMT transition is established in the framework of the generalized Maugis-Dugdale model. A refined method of matched asymptotic expansions is applied to construct the leading-order asymptotic model for indentation mapping of freestanding two-dimensional materials with an axisymmetric probe, using the approximate analytical solution obtained in explicit form for an infinite membrane in the limit of short-range adhesive contact with an indenter in the form of an elliptic paraboloid. The cases of a spherical indenter and a rectangular membrane are studied in detail.

A contact problem of electroadhesion for a conductive elastic body pressed against a rigid plane surface of a dielectric coating covering a conductive substrate is formulated applying the Johnsen-Rahbek approximation for the attractive surface stresses and the Derjaguin-Muller-Toporov (DMT) hypothesis about the influence of the adhesive stresses on the deformable shape of the elastic body. An approximate solution is obtained using the Winkler-Fuss deformation model with the equivalent (contact load dependent) stiffness coefficient evaluated according to the Xydas-Kao soft finger model. The friction force under applied voltage is evaluated as the product of the coefficient of friction and the integral of the macro contact pressure over the apparent contact area. The upper and lower estimates for the friction force are discussed in the case of absence of any external normal load.

A simple mathematical model for free vibrations of an elastically clamped beam is suggested to interpret the results of the resonance frequency analysis developed for implant stability measurements in terms of the Implant Stability Quotient (ISQ) units. It is shown that the resonance frequency substantially depends on the lateral compliance of the implant/bone system. Based on the notion of the lateral stiffness of the implant/bone system, a new measure of the implant stability is introduced in the form similar to the ISQ scale and is called the Implant Clamping Quotient (ICQ), because it characterizes the jawbone’s clamp of the implant. By definition, the ICQ unit is equal to a percentage of the original scale for the lateral stiffness of the implant/bone system.

A first-order asymptotic model for describing waves propagating along the surface of a functionally graded isotropic elastic half-space is constructed in the long-wave limit under the assumption of a finitely supported perturbation of the half-space properties. Explicit approximations for the Rayleigh waves are derived under the assumption that the semi-infinite elastic medium is slightly inhomogeneous

The problem of contact deformation of an elastic body loaded by gravitational forces and laying on several small rigid supports is considered in the framework of the linear theory of elasticity. Using the method of matched asymptotic expansions, the limit asymptotic model for determining the support reactions and the kinematic parameters of the body settling is derived. The effect of the body surface reinforcement is discussed. The case of a uniform (symmetric) settling is considered in detail.

Application of artificial neural networks (ANNs) for modeling of vapor-liquid equilibrium in multicomponent mixtures is considered. Two novel ANN-based models are introduced, which can be seen as generalizations of the Wilson model and the NRTL model. A unique feature of the proposed approach is that an ANN approximation for the molar excess Gibbs energy generates approximations for the activity coefficients. A special case of the ternary acetic acid-n-propyl alcohol-water system (at 313.15 K) is used to illustrate the efficiency of the different models, including Wilson's model, Focke's model, and the introduced generalized degree-1 homogeneous neural network model. Also, the latter one-level NN model is compared to the Wilson model on 10 binary systems. The efficiency of the two-level NN model is assessed by a comparison with the NRTL model. (C) 2019 Elsevier B.V. All rights reserved.

The so-called minimal model is formulated for describing the enthalpy relaxation and recovery in glass transition. The model is based on the Arrhenius law for the enthalpy relaxation, which uses two-dimensional parameters, namely the activation energy and the so-called pre-factor (relaxation time at relatively high temperature). A numerically effective exact analytical solution is obtained for the case of constant-rate differential scanning calorimetry. The developed model is analyzed according to the logic of the model itself without introducing additional simplifying assumptions of thermodynamic nature. For typical range of the model parameters, the resulting differential equation contains a large parameter, which offers an opportunity for the application of asymptotic and approximate techniques. A number of simple approximations have been provided for some thermodynamic quantities of interest.

An axisymmetric frictionless adhesive contact problem for a spherical indenter pressed against an isotropic elastic incompressible half-space under equibiaxial stretching is studied in the framework of the generalized Johnson-Kendall-Roberts (JKR) theory, which accounts for the effect of weak coupling between fracture modes I and II by means of a phenomenological mode-mixity function. The model predicts that contact area can withstand a larger level of the substrate stretch under moderate pre-pulling force. We have provided simple formulas to evaluate the pull-off force and the critical contact radius at the detachment point.

Adhesive contact of the Hertzian indenter with an incompressible elastic substrate bi-directionally stretched along the indenter principal planes of curvature is considered in the Johnson-Kendall-Roberts theoretical framework. An approximate model is constructed by examining energy release rate conditions only on the edges of the minor and major axes of the contact ellipse. The effect of weak coupling between fracture modes I and II is introduced using a phenomenological mode-mixity function. This study was motivated by the need to model a passive-adhesive mechanism in cell mechanics on stretchable substrates.

We present extensive multiconfiguration Dirac-Hartree-Fock and relativistic configuration interaction calculations including 106 states in doubly ionized silicon (Si III) and 45 states in triply ionized silicon (Si IV), which are important for astrophysical determination of plasma properties in different objects. These calculations represents an important extension and improvement of earlier calculations especially for Si III. The calculations are in good agreement with available experiments for excitation energies, transition properties, and lifetimes. Important deviations from the NIST-database for a selection of perturbed Rydberg series are discussed in detail.

Multiconfiguration Dirac-Hartree-Fock (MCDHF) and relativistic configuration interaction (RCI) calculations are performed for 22 states in singly ionized tin (Sn II) belonging to the 5s2ns (n=6,7), 5s2nd (n=5,6), 5s5p2 even parity configurations and the 5s2np (n=5,6,7), 5s24f odd parity configurations. Valence-valence and core-valence correlation effects are taken into account through configuration state function (CSF) expansions. Complete and consistent data sets of level energies, wavelengths, oscillator strengths, lifetimes and transition rates among all these states are given. The results are compared with existing theoretical and experimental results. There is an excellent agreement for calculated excitation energies with experimental data from the NIST database. Lifetimes and transition rates are also in agreement with the results from previous calculations and available measurements for most of the transitions.

We have in a previous study introduced a novel elliptic operator Delta((p,q))u = vertical bar del u vertical bar(q) Delta(1)u + (p - 1) vertical bar del u vertical bar(p-2)Delta(infinity) u, p >= 1, q >= 0, as a generalization of the p-Laplace operator. In this paper, we establish the well-posedness of the parabolic equation u(t) =vertical bar del u vertical bar(1-q) Delta((1+q,q)), where q = q(vertical bar del u vertical bar) is continuous and has range in [0, 1], in the framework of viscosity solutions. We prove the consistency and convergence of the numerical scheme of finite differences of this parabolic equation. Numerical simulations shows the advantage of this operator applied to image enhancement.

Den ökande växthuseffekten bidrar till uppvärmning av vår planet och byggbranschen står fören betydande del av utsläppen. I Sverige står bygg- och fastighetssektorn för 21 procent av detotala utsläppen av växthusgaser där importvaror inkluderas. Uppförande av nya byggnaderstår för en tredjedel av de totala utsläppen som orsakas av Bygg- och fastighetssektorn.Sverige har som mål att uppnå noll nettoutsläpp senast år 2045. Trots en minskning med 45procent utsläpp av växthusgaser inom bygg- och fastighetssektorn, krävs det ytterligareåtgärder för att uppnå Sveriges klimatmål.Syftet med studien är att undersöka hur mycket beräknad klimatpåverkan skiljer sig åt omklimatdatan till största del består av specifik data respektive generisk data. I studienundersöktes vilka skillnader som uppstår vid framtagning av klimatdeklarationer i tre olikaprogramvaror.För uppnå studiens syfte och besvara uppsatta frågeställningar utfördes en litteraturstudie,intervjustudie och en kvantitativ undersökning. Intervjustudien bestod av 10 respondentersom arbetar med klimatdeklarationer dagligen. Den kvantitativa undersökningen baserades påatt ta fram fem olika klimatdeklarationer för en fiktiv byggnad som tillhandahölls frånOneClick LCA.Fem olika klimatdeklarationer togs fram, där tre av klimatdeklarationerna utfördes iberäkningsverktyget Oneclick-LCA, ett i Bidcon och ett i beräkningsverktyget IVL-BM. Tvåav de tre klimatberäkningar som utfördes i Oneclick-LCA baserades på cirka 90 procentspecifik klimatdata i form av EPD:er där den faktiska klimatpåverkan för en produktredovisas. Den tredje klimatberäkningen framtagen Oneclick-LCA baserades på endastgenerisk klimatdata från Boverkets klimatdatabas. I beräkningsverktyget Bidcon och IVL-BMbaserades klimatberäkningarna på endast generisk klimatdata från boverkets klimatdatabas.Nämnda programvaror är mest kända bland utvalda respondenter. Resultatet avklimatdeklarationerna redovisas nedan.

● Oneclick LCA specifik klimatdata 1: 230 600 kg CO₂e

● Oneclick- LCA specifik klimatdata 2: 179 300 kg CO₂e

● OneClick LCA generisk klimatdata: 269 000 kg CO₂e

● Bidcon generisk klimatdata: 273 000 kg CO₂e

● IVL Byggsektorns miljöberäkningsverktyg generisk klimatdata: 266 000 kg CO₂e

Studien visade att skillnaden på den totala beräknade klimatpåverkan är marginell mellan deolika beräkningsprogrammen som undersöktes. Studien visade även att klimatberäkningarsom till största del baseras på specifik data resulterar i en lägre beräknad klimatpåverkan ijämförelse med generisk data. Trots val av EPD:er med hög klimatpåverkan blev resultatet avden totala beräknade klimatpåverkan 16 procent lägre i jämförelse med generisk data.

Försäljningen av trehjuliga motorcyklar beräknas att öka de kommande åren. Efterfrågan ökar framför allt på eldrivna trehjuliga motorcyklar. För att lyckas i fordonsbranschen behöver fordonen som utvecklas vara säkra. Säkerhet är av hög prioritet i utvecklingen av Omotion AB:s fordon. OMotion har två problem med sin senaste trehjuliga motorcykel där lösningarna kan bidra till ökad säkerhet. Instrumentpanel bakom ratt skyms när ratten vrids. Föregående modell av styrsystemet interagerar ej med 3D-modellen av fordonet på ett verklighetstroget sätt. Nytt koncept med prototyp av display tas fram med en produktutvecklingsprocess. Produktutvecklingsprocessen innefattar en konceptutveckling, utveckling på systemnivå, detaljutveckling och testning. 3D-modell för nytt styrsystem som interagerar på ett korrekt sätt tas fram med CAD-programmet SolidWorks. Enklare fysikaliska beräkningar utförs med kunskap inom hållfasthetslära och maskinelement. Resultatet är lösningar på OMotions två problem. En fysisk och analytisk prototyp för rattens integrerade display är framtagen samt en verklighetstrogen 3D-modell av styrsystemet. Styrsystemsmodellen möjliggör styrning av motorcykelmodellen i SolidWorks. 

The relativistic multiconfiguration Dirac-Hartree-Fock and the nonrelativistic multiconfiguration Hartree-Fock methods have been employed to calculate the magnetic dipole and electric quadrupole hyperfine structure constants of zinc. The calculated electric field gradients for the 4s4p P-3(1)degrees and 4s4p P-3(2)degrees states, together with experimental values of the electric quadrupole hyperfine structure constants, made it possible to extract a nuclear electric quadrupole moment Q((67) Zn) = 0.122(10) b. The error bar was evaluated in a quasistatistical approach-the calculations were carried out with 11 different methods, and then the error bar was estimated from the differences between the results obtained with those methods.

In previous work devoted to ab initio calculations of hyperfine-structure constants in nitrogen and fluorine atoms, we observed sizable relativistic effects, a priori unexpected for such light systems, that can even largely dominate over electron correlation. We observed that the atomic wave functions calculated in the Breit-Pauli approximation describe adequately the relevant atomic levels and hyperfine structures, even in cases for which a small relativistic LS-term mixing becomes crucial. In the present work we identify levels belonging to the spectroscopic terms 2p(4)(P-3)3d(2,4)(P, D, F) of the fluorine atom, for which correlation effects on the hyperfine structures are small, but relativistic LS-term admixtures are decisive to correctly reproduce the experimental values. The Breit-Pauli analysis of the hyperfine matrix elements nails cases with large cancellation, either between LS pairs for individual hyperfine operators or between the orbital and the spin dipole contributions. Multiconfiguration Dirac-Hartree-Fock calculations are performed to support the Breit-Pauli analysis.

The cleaning process of the bimetallic Pt3Sn(111) surface has been studied by means of low-energy electron microscopy (LEEM), microspot low-energy electron diffraction (mu.-LEED), and X-ray photoemission electron microscopy (XPEEM). Different cleaning procedures, performed under ultra-high vacuum conditions (UHV), including sputtering with argon ions and repeated cycles of annealing up to 1500 K were investigated. In this work, we show that a clean Pt3Sn(111) surface of high structural quality with a sharp and brilliant (2 x 2) bulk reconstruction in LEED as well as a perfectly smooth surface with terraces of micron size can be achieved by sputtering, annealing at very high temperatures, followed by a subsequent slow (0.09 K/s) and careful cooling procedure. Additionally, we show the possibility of tailoring the Sn concentration in the topmost layers of Pt3Sn(111) as a function of annealing temperature and subsequent cooling rate. Structural changes of the surface are induced by Sn segregation combined with a surface order-disorder transition at 1340 K. Moreover, two new surface reconstructions depending on the cooling rate are reported.

Context. Elemental abundances can be determined from stellar spectra, making it possible to study galactic formation and evolution. Accurate atomic data is essential for the reliable interpretation and modeling of astrophysical spectra. In this work, we perform laboratory studies on neutral aluminium. This element is found, for example, in young, massive stars and it is a key element for tracing ongoing nucleosynthesis throughout the Galaxy. The near-infrared (NIR) wavelength region is of particular importance, since extinction in this region is lower than for optical wavelengths. This makes the NIR wavelength region a better probe for highly obscured regions, such as those located close to the Galactic center.

Aims. We investigate the spectrum of neutral aluminium with the aim to provide oscillator strengths (f-values) of improved accuracy for lines in the NIR and optical regions (670–4200 nm).

Methods. Measurements of high-resolution spectra were performed using a Fourier transform spectrometer and a hollow cathode discharge lamp. The f-values were derived from experimental line intensities combined with published radiative lifetimes.

Results. We report oscillator strengths for 12 lines in the NIR and optical spectral regions, with an accuracy between 2 and 11%, as well as branching fractions for an additional 16 lines.

Denna kunskapssammanställning över bland annat regelverk, vägledningar och frivilligakrav för ljus, dagsljus, solljus, utblick och belysning visar att det finns många verktyg attta hjälp av för att styra kvaliteten inom området. Det är viktigt med robusta lösningar försådant som inverkar på människors hälsa.

Vid stadsförtätning och maximering av markanvändning finns en risk att dagsljusnivåer ibefintliga byggnader minskar kraftigt. Många nya stadsdelar byggs med så hög täthet attdagsljustillgången inte lever upp till dagens krav i alla vistelserum. Kvantitativadagsljuskraven fungerar som en garant för att trender att rationalisera bort tillgång tilldagsljus och utblick inte drivs alltför långt.

Det finns inslag i moderna byggprojekt som bidrar till lägre energianvändning somsamtidigt leder till lägre dagsljusinsläpp. Minskad fönsterarea ger som konsekvensminskad dagsljusnivå vilken i sin tur får följden att elektrisk belysning måste tändasoftare, särskilt på lägre våningar. Dagsljus är en fri/gratis ljus- och energikälla, sombidrar till resiliens vid elavbrott.

Elektrisk belysning är ett relativt nytt fenomen. Glödlamporna och lysrören uppfannsomkring 1880 respektive 1930 dvs. för mindre än 150 år sedan. Före dessa uppfinningarvar alla byggnader belysta av dagsljus och byggplanerna och stadsplaneringen ritadesnoggrant för att säkerställa god tillgång till dagsljus.

Med dagens energi- och elkris är det värt att poängtera att en av de viktigasteenergikällorna (dagsljus) och också styr tidsanpassning och påverkar utvecklingen avalla arter på jorden, inklusive människor, ända ner till cellnivå. Ny forskning publicerasvarje månad som visar hur varje band av den elektromagnetiska strålningen - från UVtill infraröd - är kopplad till dygnsrytmen och att dygnsrytmen är allmänt grundläggandeför hälsa.

Det är viktigt att byggbranschen håller sig ajour med pågående medicinsk forskning omcirkadiska cykler och hur dagsljus, solljus, utblick och belysning på verkar hälsa.Nya rekommendationer kommer allt tätare.

Många av de byggtekniska åtgärder som används för att reducera buller påverkardagsljustillgång och till en viss del även utblick negativt. Vid tekniskt samråd är det inteovanligt att akustikkrav väger tyngre än kraven på dagsljus samt utblick.

Några av de senaste trenderna i utformningen av nya byggprojekt har lett till reduceradedagsljusnivåer inomhus (t.ex. oregelbunden och asymmetrisk placering av fönster,mörka fasadmaterial, avskärmning via fasadelement).

Elektrisk belysning inomhus behöver utformas för att underlätta seendet, dvs. utanflimmer och bländning. En god visuell miljö minskar mängden ögonbesvär, huvudvärk,muskel och ledbesvär och kan påverka prestationsförmåga och produktivitet på ettpositivt sätt.

I detaljplaner fastställs förutsättningarna för exploateringsgraden. Byggnadersmöjligheter att uppfylla krav på ljus, dagsljus, solljus och utblick ska prövas.Vid framtagande av detaljplaner är det därför viktigt att se till att kraven är möjliga attuppfyllas. Idag finns många verktyg som också lämpar sig för tidiga skeden, men det ärinte alltid som de tillämpas eller att exploateringsgraden anpassas till resultaten i destudier som görs. Vid hantering först vid startbesked är projekteringsarbetet långtframskridet och anmärkningar skulle få stora konsekvenser.

När alla rum i kritiska lägen kontrolleras i projekteringen är det vanligt med avvikelserfrån kraven på dagsljusfaktor. En del kan lösas på ritbordet men inte allt. Ibland ärförutsättningarna för svåra och det går inte att hitta lösningar som tillgodoser alla krav.Djupa rum ger svårare förutsättningar än grunda rum, eftersom ljuset avtar kraftigt medavståndet från fönstret.

I en tätt byggd stad har inte alla samma möjlighet att välja boende – högst upp i huseteller i gathuset där dagsljuset flödar. Mycket få föredrar mörkare bostäder men många ärberedda att kompromissa bort dagsljustillgången för att få tillgång till stadens puls.Dagsljus ska inte bara vara en lyx som privilegierade kan unna sig, det ska vara entillgängligt för alla.

I tätbebyggda kvarter är det ofta en utmaning att efterleva regelverket. Dagsljuset i Sverige är relativt svagt, och lågt stående sol, dessutom ofta skymd av omgivandebyggnader, ger långa skuggor. Historien visar att svenska städer kan förse alla boendemed ljusa bostäder men om förtätandet fortsätter enligt samma mönster som tidigare såmåste både lagstiftare och planaktörer ha verktyg att förstå dess begränsningar.Misslyckas planeringen av framtidens städer finns en risk att hälsa och välmående för desom bor i den attraktiva kvartersstaden i all mening äventyras.

Folkhälsomyndigheten och Arbetsmiljöverket utgår från att brist på dagsljus kan genegativa effekter för hälsan. Uppskattningsvis 80 % av levnadstiden spenderas inomhus.Det är en av anledningarna att miniminivåer för dagsljus i vistelserum är nödvändiga ibyggregler.

Dagsljusfaktorn är ett bra mått för att bedöma tillgången av dagsljus. Dagsljusfaktornbeskrivs i en nyare standard där den bedöms över en yta och inte i en punkt.BBR hänvisar till föråldrade metoder. Ett kvantitativt dagsljuskrav säkerställer attvistelserum erhåller tillräckligt med dagsljus för att inte riskera människors hälsa.Byggnadens gestaltning får inte riskera människors tillgång till ett hälsosamtdagsljusinsläpp.

Boverket ser ett behov av en kunskapssammanställning kring nuläget inom termisk komfort i Sverige för att ha en så bred och korrekt förståelse som möjligt för vem branschen är, vilka regler som tillämpas, var det finns kunskapscentra och vilka utvecklingsbehov som behöver stödjas för att branschen ska kunna ta större ansvar.

Några faktafrågeställningar som vi författare noterat och som kan vara värda att kartlägga ytterligare:

Metoder att simuleraKlimatdata för analyser och simuleringarBetydelsen av värmeöarÅtgärder för att minska värmelaster på byggnaderörbereda plats i byggnader för komfortkylaRisker med fukt och påväxt vid komfortkylaPrioriterade rum för termisk komfortUpplåtelseformers inverkan, utsatta grupper och lokala reglerVädring och fläktarPrioritera passiva åtgärderPortabel luftkylning/komfortkylaTillsyn och bygglovKrav som inte är samordnade (energi, dagsljus, buller, etc.)VarningssystemFörhoppningen är att kartläggning av termisk komfort ska bidra till kunskapsspridning om bransch, aktörer, teknik, system, konstruktion, kontroller, drift och underhåll samt forskning och utveckling.

The high-resolution Sentinel-2 data potentially enable the estimation of gross primary productivity (GPP) at finer spatial resolution by better capturing the spatial variation in a heterogeneous landscapes. This study investigates the potential of 10 m resolution reflectance from the Sentinel-2 Multispectral Instrument to improve the accuracy of GPP estimation across Nordic vegetation types, compared with the 250 m and 500 m resolution reflectance from the Moderate Resolution Imaging Spectroradiometer (MODIS). We applied linear regression models with inputs of two-band enhanced vegetation index (EVI2) derived from Sentinel-2 and MODIS reflectance, respectively, together with various environmental drivers to estimate daily GPP at eight Nordic eddy covariance (EC) flux tower sites. Compared with the GPP from EC measurements, the accuracies of modelled GPP were generally high (R-2 = 0.84 for Sentinel-2; R-2 = 0.83 for MODIS), and the differences between Sentinel-2 and MODIS were minimal. This demonstrates the general consistency in GPP estimates based on the two satellite sensor systems at the Nordic regional scale. On the other hand, the model accuracy did not improve by using the higher spatial-resolution Sentinel-2 data. More analyses of different model formulations, more tests of remotely sensed indices and biophysical parameters, and analyses across a wider range of geographical locations and times will be required to achieve improved GPP estimations from Sentinel-2 satellite data.

Since 2002, the European Union (EU) has promoted individual metering of energy consumption as an ef- fective tool to improve energy efficiency in buildings. In 2012, the Energy Efficiency Directive has set mandatory the individual heat accounting in buildings when centralized heating/cooling systems are present, when technically feasible and cost efficient. As a consequence, EU Member States adopted dif- ferent allocation rules mainly due to differences in building stocks and climatic conditions. This measure has led to a series of technical, legal and consumer protection issues which still need to be solved. In this paper, more than 130 publications have been analysed and critically reviewed, highlighting the dif- ferent approaches adopted in EU Member States concerning heat accounting and the related issues. To this aim, the authors focussed the following subjects: (i) the allocation rules adopted by EU Member States, (ii) the heat metering and sub-metering technologies, (iii) the cost-benefit analysis of individual heat metering and accounting systems. This review is useful for researchers since the existing regulation and technologies for heat accounting and their related potential are discussed together with the analysis of the existing gap in terms of technical standard and consumer protection. Finally, the analysis provides policy makers with several suggestions to improve transparency and reliability of allocation rules.

Refractory high/medium entropy nitrides (HENs/MENs) exhibit comprehensive application prospects as protective films on mechanical parts, particularly those subjected to sliding contacts at elevated temperatures. In this study, a new MEN system TiNbWN, forming a single fcc solution, is designed and its wear performance at temperatures ranging from 25 to 750 °C is explored. The wear mechanisms can be rationalized by examining the subsurface microstructural evolutions using the transmission electron microscopy as well as calculating the phase diagrams and interfacial adhesion behavior employing calculation of phase diagram (CALPHAD) and density functional theory (DFT). To be specific, increased wear losses occur in a temperature range of 25–600 °C, being predominantly caused by the thermally-induced hardness degradation; whereas at the ultimate temperature (750 °C), the wear loss is refrained due to the formation of nanocrystalline oxides (WnO3n−2, TiO2, and γTiOx), as synergistically revealed by microscopy and CALPHAD, which not only enhance the mechanical properties of the pristine nitride film, but also act as solid lubricants, reducing the interfacial adhesion. Thus, our work delineates the role of the in situ formed nanocrystalline oxides in the wear mechanism transition of TiNbWN thin films, which could shed light on the high-temperature wear behavior of refractory HEN/MEN films.

An extensive set of level energies, wavelengths, line strengths, oscillator strengths, lifetimes, hyperfine structures, Lande g(J)-factors, electric dipole (E1), magnetic dipole (M1), electric quadrupole (E2), and magnetic quadrupole (M2) radiative transition rates among the lowest 318 states arising from the 2s(2)2p(4), 2s2(p)5, 2p(6), 2s(2)2p(3)3l (l = 0, 1, 2), 2s2p(4)31 (l = 0, 1, 2), 2p(5)3l (l = 0, 1, 2), and 2s(2)2p(3)4l (l = 0, 1, 2, 3) configurations has been obtained for Se XXVII. These new data, calculated within the frameworks of the multi-configuration Dirac-Hartree-Fock method and the second-order many-body perturbation theory, fill in the gap existing in the atomic data needed for the diagnostic processes of tokamak plasmas. Using two methods allowed us to make an intercomparison and to estimate the uncertainties on the obtained data. The results arising in the two sets of calculations are quite close, suggesting that there is a high degree of convergence achieved in our work. i.e., our two sets of energies agree to better than 0.02%, and the lifetimes mostly agree to within 2%. Comparison is also made with the limited number of experimental data and previous computations to assess the accuracy of our calculations. (C) 2017 Elsevier Ltd. All rights reserved.

The individual heat cost allocation is one of the recent topics which is well-known not only for the possibility of increasing the energy efficiency but also for the related problems. However, there is no comprehensive work where the main problems are shown and adequate solutions are proposed. This article presents the main aspects which are important in the area of heat cost allocation. Firstly, the policy issues were underlined and the recommendations for the introduction of general rules for heating costs allocation at the level of a given country were provided. Secondly, the main possibilities, problems and solutions connected to the devices and methods for heat cost allocation were introduced. Then, the energy savings obtained using heat cost allocation were shown on the example of long term field research (8 heating seasons) carried out for six residential buildings, where heat cost allocators were uninstalled. Lastly, comprehensive recommendations were provided, the introduction of which will allow to minimizing the problems connected with heat cost allocation and maximizing the energy savings while maintaining the thermal comfort in the heated rooms.

Context. Classical Cepheids (CCs) are solid distance indicators and tracers of young stellar populations. Dating back to the beginning of the 20th century, they have been safely adopted to trace the rotation, kinematics, and chemical enrichment history of the Galactic thin disk.

Aims. The main aim of this investigation is to provide iron, oxygen, and sulfur abundances for the largest and most homogeneous sample of Galactic CCs analyzed so far (1118 spectra of 356 objects). The current sample, containing 70 CCs for which spectroscopic metal abundances are provided for the first time, covers a wide range in galactocentric distances, pulsation modes, and pulsation periods.

Methods. Optical high-resolution spectra with a high signal-to-noise ratio that were collected with different spectrographs were adopted to provide homogeneous estimates of the atmospheric parameters (effective temperature, surface gravity, and microturbulent velocity) that are required to determine the abundance. Individual distances were based either on trigonometric parallaxes by the Gaia Data Release 3 (Gaia DR3) or on distances based on near-infrared period-luminosity relations.

Results. We found that iron and α-element radial gradients based on CCs display a well-defined change in the slope for galactocentric distances larger than ~12 kpc. We also found that logarithmic regressions account for the variation in [X/H] abundances from the inner to the outer disk. Radial gradients for the same elements, but based on open clusters covering a wide range in cluster ages, display similar trends. This means that the flattening in the outer disk is an intrinsic feature of the radial gradients because it is independent of age. Empirical evidence indicates that the S radial gradient is steeper than the Fe radial gradient. The difference in the slope is a factor of two in the linear fit (−0.081 vs. −0.041 dex kpc−1) and changes from −1.62 to −0.91 in the logarithmic distance. Moreover, we found that S (explosive nucleosynthesis) is underabundant on average when compared with O (hydrostatic nucleosynthesis). The difference becomes clearer in the metal-poor regime and for the [O/Fe] and [S/Fe] abundance ratios. We performed a detailed comparison with Galactic chemical evolution models and found that a constant star formation efficiency for galactocentric distances larger than 12 kpc accounts for the flattening observed in both iron and α-elements. To further constrain the impact of the predicted S yields for massive stars on radial gradients, we adopted a toy model and found that the flattening in the outermost regions requires a decrease of a factor of four in the current S predictions.

Conclusions. CCs are solid beacons for tracing the recent chemical enrichment of young stellar populations. Sulfur photospheric abundances, when compared with other α-elements, have the key advantage of being a volatile element. Therefore, stellar S abundances can be directly compared with nebular sulfur abundances in external galaxies.