Investigation of hybrid manufacturing of stainless steel 316L components using direct energy deposition

Direct energy deposition (DED) has been established as one of the methods for additive manufacturing metallic parts. The combination of DED capabilities with traditional machining centre capabilities has enabled over the past few years the creation of Hybrid manufacturing cells that are able to additively manufacture and finish machine components under one platform. This paper investigates the production of geometries using a hybrid, additive and subtractive approach. The parameters for depositing stainless steel 316L are initially investigated followed by an assessment of machinability of the additively manufactured material. Finally the quality of the deposited and machined material was thoroughly examined with a series of destructive and nondestructive methods

A new species of australian frog (Myobatrachidae:Uperoleia) from the New South Wales mid-north coast sandplains

The discovery of new vertebrate species in developed countries is still occurring at surprising rates for some taxonomic groups, especially the amphibians and reptiles. While this most often occurs in under-explored areas, it occasionally still happens in well-inhabited regions. We report such a case with the discovery and description of <i>U. mahonyi</i> <b>sp. nov.</b>, a new species of frog from a highly populated region of New South Wales, Australia. We provide details of its morphology, calls, embryos and tadpoles, and phylogenetic relationships to other species of eastern <i>Uperoleia</i>. We also provide the results of targeted surveys to establish its distribution and provide observations of its habitat associations. As a consequence of these surveys, we comment on the likely restricted nature of the species' distribution and habitat, and place this in the context of a preliminary assessment of its putative conservation status, which should be assessed for listing under the IUCN's red list. We note this species, which is morphologically distinct, has gone unnoticed for many decades despite numerous eco-logical surveys for local development applications

Perovzalates : a family of perovskite-related oxalates

Authors would like to thank the University of St Andrews (studentship to AJB) and the EPSRC (doctoral studentship to RC: DTG012 EP/K503162-1) for funding.A family of hybrid Perovskite-oxalates (“Perovzalates”) of general composition AILi3MII(C2O4)3 (A = K+, Rb+, Cs+; M = Fe2+, Co2+, Ni2+) are presented. All eight new compounds are isostructural with the previously reported examples NH4Li3Fe(C2O4)3 and KLi3Fe(C2O4)3, crystallising in the rhombohedral space group Rc, with a ∼11.3–11.6 Å, c ∼14.8–15.2 Å. In contrast to other families of “hybrid perovskites” such as the formates, these compounds can be regarded as closer structural relatives to inorganic (oxide) perovskites, in the sense that they contain direct linkages of the octahedral sites via bridging oxygen atoms (of the oxalate groups). It is of note, therefore, that monoatomic cations as large as Cs+ can be incorporated into the perovskite-like A sites of this structure type, which is not feasible in traditional ABO3 perovskites; indeed CsLi3Ni(C2O4)3 appears to exhibit the ‘mostly tightly bound’ 12-coordinate Cs+ ion in an oxide environment, according to a bond valence analysis.PostprintPeer reviewe

Formal Analysis of Key Integrity in PKCS#11

PKCS#11 is a standard API to cryptographic devices such as smarcards, hardware security modules and usb crypto-tokens. Though widely adopted, this API has been shown to be prone to attacks in which a malicious user gains access to the sensitive keys stored in the devices. In 2008, Delaune, Kremer and Steel proposed a model to formally reason on this kind of attacks. We extend this model to also describe flaws that are based on integrity violations of the stored keys. In particular, we consider scenarios in which a malicious overwriting of keys might fool honest users into using attacker’s own keys, while performing sensitive operations. We further enrich the model with a trusted key mechanism ensuring that only controlled, non-tampered keys are used in cryptographic operations, and we show how this modified API prevents the above mentioned key-replacement attacks

Security by Spatial Reference:Using Relative Positioning to Authenticate Devices for Spontaneous Interaction

Spontaneous interaction is a desirable characteristic associated with mobile and ubiquitous computing. The aim is to enable users to connect their personal devices with devices encountered in their environment in order to take advantage of interaction opportunities in accordance with their situation. However, it is difficult to secure spontaneous interaction as this requires authentication of the encountered device, in the absence of any prior knowledge of the device. In this paper we present a method for establishing and securing spontaneous interactions on the basis of emphspatial references that capture the spatial relationship of the involved devices. Spatial references are obtained by accurate sensing of relative device positions, presented to the user for initiation of interactions, and used in a peer authentication protocol that exploits a novel mechanism for message transfer over ultrasound to ensures spatial authenticity of the sender

From Waste to Employment Opportunities and Wealth Creation: A Case Study of Utilization of Livestock By-Products in Hargeisa, Somaliland

This article was conducted to establish the involvement of vulnerable women and youths in creating alternative employment opportunities and diversify wealth creation livelihood activities through DFID UKaid Sustainable Employment and Economic Development (SEED) funded programme and implemented by FAO Somalia in the security fragile state of Somaliland.Mqaalkan waxaa loo sameeyey si haweenka nugul loogu abuuro shaqo ay ka heli karaan masaruufka reerka. Waxaana barnaamijlaas Hargeysa ku hirgeliyay FAO (DFID UK e SEED).Questo articolo è stato condotto per stabilire la partecipazione di donne vulnerabili e giovani nella creazione di opportunità di lavoro alternative e nella diversificazione delle attività creatrici di sostentamento attraverso programmi DFID UK e SEED sovvenzionati dalla FAO in Somaliland

Extending periodic eddy covariance latent heat fluxes through tree sap-flow measurements to estimate long-term total evaporation in a peat swamp forest

A combination of measurement and modelling was used to find a pragmatic solution to estimate the annual total evaporation from the rare and indigenous Nkazana Peat Swamp Forest (PSF) on the east coast of Southern Africa to improve the water balance estimates within the area. Actual total evaporation (ETa) was measured during three window periods (between 7 and 9 days each) using an eddy covariance (EC) system on a telescopic mast above the forest canopy. Sap flows of an understory tree and an emergent tree were measured using a low-maintenance heat pulse velocity system for an entire hydrological year (October 2009 to September 2010). An empirical model was derived, describing the relationship between ETa from the Nkazana PSF and sap-flow measurements. These overlapped during two of the window periods (R2 = 0.92 and 0.90), providing hourly estimates of ETa from the Nkazana PSF for a year, totalling 1125 mm (while rainfall was 650 mm). In building the empirical model, it was found that to include the understory tree sap flow provided no benefit to the model performance. In addition, the relationship between the emergent tree sap flow with ETa between the two field campaigns was consistent and could be represented by a single empirical model (R2 = 0.90; RMSE = 0.08 mm h−1). During the window periods of EC measurement, no single meteorological variable was found to describe the Nkazana PSF ETa satisfactorily. However, in terms of evaporation models, the hourly FAO Penman–Monteith reference evaporation (ETo) best described ETa during the August 2009 (R2 = 0.75), November 2009 (R2 = 0.85) and March 2010 (R2 = 0.76) field campaigns, compared to the Priestley–Taylor potential evaporation (ETp) model (R2 = 0.54, 0.74 and 0.62 during the respective field campaigns). From the extended record of ETa (derived in this study from sap flow) and ETo, a monthly crop factor (Kc) was derived for the Nkazana PSF, providing a method of estimating long-term swamp forest water-use from meteorological data. The monthly Kc indicated two distinct periods. From February to May, it was between 1.2 and 1.4 compared with June to January, when the crop factor was 0.8 to 1.0. The derived monthly Kc values were verified as accurate (to one significant digit) using historical data measured at the same site, also using EC, from a previous study. The measurements provided insights into the microclimate within a subtropical peat swamp forest and the contrasting sap flow of emergent and understory trees. They showed that expensive, high-maintenance equipment can be used during manageable window periods in conjunction with low-maintenance systems, dedicated to individual trees, to derive a model to estimate long-term ETa over remote heterogeneous forests. In addition, the contrast in annual ETa and rainfall emphasised the reliance of the Nkazana PSF on groundwater