Background and Aiims: Percutaneous dilational tracheostomy (PDT) is a common procedure in intensive care unit (ICU) patients requiring long-term mechanical ventilation. PDT has gradually replaced ...surgical tracheostomy because it is associated with minimal invasiveness, reduced bleeding and simplicity in technique.This study was conducted to compare ultrasound-guided PDT versus conventional tracheostomy in terms of duration of the procedure, number of passes and immediate peri-procedural complications. Methods: A total of 72 patients with clinical indications of tracheostomy were recruited. A total of 12 patients met the exclusion criteria. The remaining were randomly assigned into two groups of 30 each: Group A (Landmark) with traditional anatomical landmark and Group B (USG) with real-time ultrasound guidance. Puncture positions were recorded with bronchoscopy. Midline deviation was captured on a bronchoscopy image using a protractor. Data on procedural safety and efficacy were also collected. Results: Group B had significantly fewer cases of midline deviation (11.33 ± 9.51) in comparison to Group A (16.60 ± 12.31). Trials > 2 were equal to 11 in Group A and 2 in Group B. However, the duration of the procedure was higher in Group B (20.07 ± 3.25 min) as compared to Group A (15.20 ± 3.71 min). Peri-procedural and post-procedural complications were also higher in the Landmark group. Conclusion: Ultrasound-guided PDT showed superiority over landmark PDT in terms of less number of trials, midline puncture and fewer complications. However, it took a little longer to perform USG-guided PDT.
Mechanistic modeling of micro-drilling cutting forces Anand, Ravi Shankar; Patra, Karali; Steiner, Markus ...
International journal of advanced manufacturing technology,
2017/1, Letnik:
88, Številka:
1-4
Journal Article
Recenzirano
This paper presents a mechanistic model for micro-drilling cutting forces that includes the cutting edge radius and the minimum chip thickness size effects. The proposed model considers three ...different cutting regions, i.e., ploughing-dominant, transition, and shearing-dominant, based on these size effects. Specific normal force and specific friction force coefficients have been determined through model calibration using micro-drilling experimental results. Model is validated with micro-drilling experimental results of different cutting conditions and of different machining environments. Comparisons of model simulated and experimental results show that ploughing force contributions are significant, especially at low feed rates. The proposed model has also been applied to characterize size effects in micro-drilling.
Iron pisoliths and nodules are common within the fluvio-lacustrine kaolinitic clays of Tertiary paleochannels developed in the Yilgarn Craton of southern Western Australia. Deposition within these ...channels began in the Late Eocene with sediments comprised a fining upward sequence, from sands at the base, to lacustrine clay deposits above. Iron pisoliths are found randomly distributed in the clays in deposits more than 300km apart. The pisoliths are composed of goethite and hematite and minor quartz and clays, they are 2 to 30mm in diameter and formed of an inner nucleus surrounded by up to 200 iron oxide laminations. There is no evidence for transportation of pisoliths into the channels but the internal fragmented nature of some of the pisoliths suggests some movement has occurred and multiple generations of pisoliths have developed. The interface between river water and sediment was a redox boundary between reduced slightly acidic sediments and oxidised river water. Pisoliths formed on, or just beneath the surface of the sediment by redox reactions likely mediated by microorganisms. Pisoliths have undergone cycles of exposure, growth and movement linked to the height and course of the palaeoriver system.
The ferricrete units (Fe oxide cemented colluvial-alluvial sediment) of the Yilgarn Craton in Western Australia formed during the humid tropical and sub-tropical climates of the Cenozoic. Ferricretes ...are generally developed on long-lived paleodrainage systems and are products of the ferruginisation of detritus provided by the continuous erosion of upslopes. These iron-rich accumulations can become Au-enriched, as is the case in several locations previously discovered in the Yilgarn Craton; many of these host economic secondary gold deposits (e.g., Moolart Well, Mt Gibson, and Bulchina), typically occurring downslope of low saprolite hills and near paleovalleys (i.e., inset-valleys). Inset-valleys are a common paleotopographic feature buried under Quaternary alluvial and colluvial sedimentary cover. Maps of these ancient channel networks can be used as a proxy for targeting ferricrete gold deposits. These inset-valley systems generally form dendritic and noisy patterns in high-resolution aeromagnetic data due to the presence of maghemite-rich nodules and detrital magnetic pisoliths on their flanks. The main aim of this study was to use high-resolution aeromagnetic data to target ferricrete units related to inset-valleys systems across the Yilgarn Craton. A spatial predictive model was used to learn and predict the geological units of interest from pre-processed aeromagnetic data. The predicted inset-valleys systems were able to confine the exploration space and define a new exploration frontier for ferricrete gold deposits.
As the fault‐based attacks are becoming a more pertinent threat in today's era of edge computing/internet‐of‐things, there is a need to streamline the existing tools for better accuracy and ease of ...use, so that we can gauge the attacker's power and a proper countermeasure can be devised in the long run. In this regard, we propose a machine learning (ML) assisted tool that can be used in the context of a differential fault attack. In particular, finding the exact fault location by analysing the output difference (typically the XOR of the nonfaulty and the faulty ciphertexts) is somewhat nontrivial. During the literature survey, we notice that the Pearson's correlation coefficient dominantly is used for this purpose, and has almost become the defacto standard. While this method can yield good accuracy for certain cases, we argue that an ML‐based method is more powerful in all the situations we experiment with. We substantiate our claim by showing the relative performances (we choose the commonly used multilayer perceptron as our ML tool) with two variants of Grain‐128a (a stream cipher, and a stream cipher with authentication), the lightweight stream cipher LIZARD and the lightweight block cipher SIMON‐32 (where the faults are injected at the fifth last rounds). Our results demonstrate that a common ML tool can outperform the correlation with the same training/testing data. We believe that our work extends the state‐of‐the‐art by showing how traditional cryptographic methods can be replaced by a more powerful ML tool.
Ferruginous nodules and pisoliths that cap deeply weathered profiles and transported cover are characteristic of the Yilgarn Craton, Western Australia. Here we show how ferruginous nodules and ...pisoliths formed in the paleochannel sediments during Miocene can be used to locate buried Au mineralization. Three types of ferruginous nodules and pisoliths were identified in paleochannel sediments and saprolite, representing different parent materials and environments covering the Garden Well Au deposit: (i) ferruginous nodules formed in saprolite on the flanks of the paleochannel (NSP), (ii) ferruginous pisoliths formed in the Perkolilli Shale in the middle of the paleochannel (PPS) and (iii) ferruginous nodules formed in the Wollubar Sandstone at the bottom of the paleochannel (NWS). The appearance, mineralogy and geochemistry of ferruginous nodules and pisoliths vary according to their origin. The PPS and NWS are goethite-rich whereas NSP is a mixture of goethite and hematite which make them all suitable for (U–Th)/He dating. The average age of goethite in the NSP is 14.8 Ma, in the NWS is 11.2 Ma and in the PPS is 18.6 and 14 Ma. The goethite ages in ferruginous nodules and pisoliths are thought to be younger than the underlying saprolite (Paleocene-Eocene) and were formed in different environmental conditions than the underlying saprolite. Anomalous concentrations of Au, As, Cu, Sb, In, Se, Bi, and S in the cores and cortices of the NWS and the PPS reflect the underlying Au mineralization, and thus these nodules and pisoliths are useful sample media for geochemical exploration in this area. These elements originating in mineralized saprolite have migrated both upwards and laterally into the NWS and the PPS, to form spatially large targets for mineral exploration.
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