Reflected Spectrally Negative Stable Processes and their Governing Equations

This paper explicitly computes the transition densities of a spectrally negative stable process with index greater than one, reflected at its infimum. First we derive the forward equation using the theory of sun-dual semigroups. The resulting forward equation is a boundary value problem on the positive half-line that involves a negative Riemann-Liouville fractional derivative in space, and a fractional reflecting boundary condition at the origin. Then we apply numerical methods to explicitly compute the transition density of this space-inhomogeneous Markov process, for any starting point, to any desired degree of accuracy. Finally, we discuss an application to fractional Cauchy problems, which involve a positive Caputo fractional derivative in time

The role of asymmetric prediction losses in smart charging of electric vehicles

Climate change prompts humanity to look for decarbonisation opportunities, and a viable option is to supply electric vehicles with renewable energy. The stochastic nature of charging demand and renewable generation requires intelligent charging driven by predictions of charging behaviour. The conventional prediction models of charging behaviour usually minimise the quadratic loss function. Moreover, the adequacy of predictions is almost solely evaluated by accuracy measures, disregarding the consequences of prediction losses in an application context. Here, we study the role of asymmetric prediction losses which enable balancing the over- and under-predictions and adjust predictions to smart charging algorithms. Using the main classes of machine learning methods, we trained prediction models of the connection duration and compared their performance for various asymmetries of the loss function. In addition, we proposed a methodological approach to quantify the consequences of prediction losses on the performance of selected archetypal smart charging schemes. In concrete situations, we demonstrated that an appropriately selected degree of the loss function asymmetry is crucial as it almost doubles the price range where the smart charging is beneficial, and increases the extent to which the charging demand is satisfied up to 40%. Additionally, the proposed methods improve charging fairness since the distribution of unmet charging demand across vehicles becomes more homogeneous.IA4TES MIA.2021.M04.000

FORVAL for Windows: A computer program for FORest VALuation and investment analysis

FORVAL (FORest VALuation) for Windows is a computer program for cash flow analysis of forestry investments. FORVAL was written in Visual Basic and is available from the Forest and Wildlife Research Center at Mississippi State University. We designed FORVAL to be used without a manual. It is user-friendly and includes a Windows Help file. Users enter the data requested for each box on the form and then press an appropriate button to perform the desired action

First-principles study of Co- and Cu-doped Ni2MnGa along the tetragonal deformation path

The influence of Co and Cu doping on Ni-Mn-Ga Heusler alloy is investigated using the first-principles exact muffin-tin orbital method in combination with the coherent-potential approximation. Single-element doping and simultaneous doping by both elements are investigated in Ni50−xCoxMn25−yGa25−zCuy+z alloys, with dopant concentrations x,y, and z up to 7.5 at. %. Doping with Co in the Ni sublattice decreases the (c/a)NM ratio of the nonmodulated (NM) martensite, but it simultaneously increases the cubic phase stability with respect to the NM phase. Doping with Cu in the Mn or in Ga sublattices does not change the (c/a)NM ratio significantly and it decreases the cubic phase stability. For simultaneous doping by Co in the Ni sublattice and Cu in the Mn or Ga sublattices, the effects of the individual dopants are independent and about the same as for the single-element doping. Thus, the (c/a)NM ratio can be adjusted by Co doping while the phase stability can be balanced by Cu doping, resulting in stable martensite with a reduced (c/a)NM. The local stability of the cubic phase with respect to the tetragonal deformation can be understood on the basis of a density-of-states analysis.Peer reviewe

Economics of direct seeding and planting for establishing oak stands on old-field sites in the South.

On old-field sites in the South, oak stand may be established by direct seeding of acorns, or by planting seed- lings. Planting seedlings costs approximately 21/2 times the cost of direct seeding on a per acre basis, and based on our study of overall costs and returns, we conclude that in most cases the additional costs of planting are not justified by the additional benefits. Direct seeding is therefore an eco- nomically viable alternative to planting, although success with seeding requires careful selection of species/site combinations and proper seed handling and storag

Analiza dubine toplinski pogođene zone površine uzorka kod strojne obrade električnim pražnjenjem s mesinganom žičanom elektrodom

The article deals with detailed evaluation of the depth of heat-affected zone in sub-surface layers of the samples made by technology of wire electrical discharge machining with brass electrode. It is vital to remark at the beginning that the heat impact is an undesirable phenomenon from the standpoint of operating life of parts produced by this progressive technology. Considerable depth of heat-affected zone, its characteristic, and its uneven course along cross-section, noticeably contributes to the decrease of quality and longevity of machine parts, as well as cutting tools. The samples were produced on electroerosion machine AGIECUT from tool steel of 950 MPa strength. Applied cutting tool was wire brass electrode of 0,25 mm diameter. To determine suitable HAZ depth measuring method, it was necessary to take into account properties of the given technology where impact and consecutive micro-hardness change occurs instantly after high temperature spot effect of electric discharge channel which arises between wire electrode (cutting tool) and material (workpiece) during intensive cooling in dielectric medium. Considering this aspect, the influence shows different values in longitudinal and lateral cross-sections (as of wire electrode movement relatively to the workpiece). The course of the values is in the same time greatly affected by combination of technological parameters that inevitably must observe electroerosion cutting process itself, as well as electro-chemical properties of the material. The aim of this paper is to describe the real course of micro-hardness in particular cross-sections and to give recommendations concerning adjustment of main technological parameters so as to achieve HAZ homogenity along the whole cut.Članak se bavi detaljnom procjenom dubine toplinski pogođene zone u pod-površinskim slojevima od uzoraka izrađenih pomoću tehnologije strojne obrade žičanim električnim pražnjenjem upotrebom mesingane elektrode. Važno je napomenuti na početku da je utjecaj topline nepoželjan fenomen sa stajališta operativnog života dijelova proizvedenih od strane ove progresivne tehnologije. Znatna dubina toplinski pogođene zone, njene karakteristike i neujednačena putanja duž presjeka, primjetno doprinosi smanjenju kvalitete i dugovječnosti strojnih dijelova, kao i alati za rezanje. Uzorci su proizvedeni na elektro-erozivnom stroju AGIECUT od alatnog čelika snage od 950 MPa. Primijenjeni rezni alat bila je žica tj. mesingana elektroda promjera od 0,25 mm. Za određivanje prikladne mjerne metode za dubinu toplinski pogođene zone bilo je potrebno uzeti u obzir svojstva dane tehnologije gdje su uzastopne promjene i utjecaji u mikro-tvrdoći nastali istovremeno poslije efekta točke visoke temperature kanala električnog pražnjenja koji nastaje između elektrode žice (reznog alata) i materijala (obradak) tijekom intenzivnog hlađenja u dielektričnom mediju. S obzirom na ovaj aspekt, utjecaj pokazuje različite vrijednosti u uzdužnim i poprečnim presjecima (kao pokretima žičane elektrode u odnosu na obradak). Kretanje vrijednosti je u isto vrijeme uvelike pod utjecajem kombinacije tehnoloških parametara koji neizbježno moraju promatrati proces samog rezanja elektro-erozijom, kao i elektro-kemijska svojstva materijala. Cilj ovog rada je opisati stvarni tijek mikro-tvrdoće posebnim presjecima, te dati preporuke vezane uz prilagođavanje glavnih tehnoloških parametara na način da se postigne homogenost toplinski pogođene zone duž cijelog reza