LESS: Label-efficient Multi-scale Learning for Cytological Whole Slide Image Screening

In computational pathology, multiple instance learning (MIL) is widely used to circumvent the computational impasse in giga-pixel whole slide image (WSI) analysis. It usually consists of two stages: patch-level feature extraction and slide-level aggregation. Recently, pretrained models or self-supervised learning have been used to extract patch features, but they suffer from low effectiveness or inefficiency due to overlooking the task-specific supervision provided by slide labels. Here we propose a weakly-supervised Label-Efficient WSI Screening method, dubbed LESS, for cytological WSI analysis with only slide-level labels, which can be effectively applied to small datasets. First, we suggest using variational positive-unlabeled (VPU) learning to uncover hidden labels of both benign and malignant patches. We provide appropriate supervision by using slide-level labels to improve the learning of patch-level features. Next, we take into account the sparse and random arrangement of cells in cytological WSIs. To address this, we propose a strategy to crop patches at multiple scales and utilize a cross-attention vision transformer (CrossViT) to combine information from different scales for WSI classification. The combination of our two steps achieves task-alignment, improving effectiveness and efficiency. We validate the proposed label-efficient method on a urine cytology WSI dataset encompassing 130 samples (13,000 patches) and FNAC 2019 dataset with 212 samples (21,200 patches). The experiment shows that the proposed LESS reaches 84.79%, 85.43%, 91.79% and 78.30% on a urine cytology WSI dataset, and 96.88%, 96.86%, 98.95%, 97.06% on FNAC 2019 dataset in terms of accuracy, AUC, sensitivity and specificity. It outperforms state-of-the-art MIL methods on pathology WSIs and realizes automatic cytological WSI cancer screening.Comment: This paper was submitted to Medical Image Analysis. It is under revie

Modelling, Investigation of Process Responses, Surface Assessment and Parametric Optimization in Powder Mixed Electrical Discharge Diamond Grinding of TI6AL4V Utilizing Grey-Based Taguchi Approach

In this study, the powder mixed electrical discharge diamond grinding (PMEDDG) process was designed and a set-up for machining hard electrically conductive material surfaces built. The paper presents empirical models, investigation, an optimal setting of factors and the distinct surface production in the PMEDDG of Ti6Al4V with aluminium (Al) and silicon carbide (SiC) powder mixed dielectric fluid. The response surface methodology was applied to the modelling. One set of 32 experiments with Al powder and another set of 32 experiments with SiC powder mixed dielectric fluid were performed on a PMEDDG set-up. Current, pulse on time, wheel speed, duty cycle, and volumetric proportion of the powder were taken as input machining variables. Material removal rate and surface roughness were computed as outputs. The behaviour of the input factors against the responses was studied and compared with the SiC and Al powder mixed dielectric fluid used in the PMEDDG process. Further, scanning electron microscopy (SEM) investigations were carried out to determine the impact of different factors on the PMEDDG-produced surfaces as well as the effect of powder presence in the dielectric fluid on white recast layer thickness of the produced surfaces. The grey-based Taguchi approach was used to determine an optimal set of process variables when aluminium powder is used and a confirmation test was conducted on the optimal set to estimate the effectiveness of this approach

Optimisation of welding parameters to mitigate the effect of residual stress on the fatigue life of nozzle–shell welded joints in cylindrical pressure vessels.

Doctoral Degree. University of KwaZulu-Natal, Durban.The process of welding steel structures inadvertently causes residual stress as a result of thermal cycles that the material is subjected to. These welding-induced residual stresses have been shown to be responsible for a number of catastrophic failures in critical infrastructure installations such as pressure vessels, ship’s hulls, steel roof structures, and others. The present study examines the relationship between welding input parameters and the resultant residual stress, fatigue properties, weld bead geometry and mechanical properties of welded carbon steel pressure vessels. The study focuses on circumferential nozzle-to-shell welds, which have not been studied to this extent until now. A hybrid methodology including experimentation, numerical analysis, and mathematical modelling is employed to map out the relationship between welding input parameters and the output weld characteristics in order to further optimize the input parameters to produce an optimal welded joint whose stress and fatigue characteristics enhance service life of the welded structure. The results of a series of experiments performed show that the mechanical properties such as hardness are significantly affected by the welding process parameters and thereby affect the service life of a welded pressure vessel. The weld geometry is also affected by the input parameters of the welding process such that bead width and bead depth will vary depending on the parametric combination of input variables. The fatigue properties of a welded pressure vessel structure are affected by the residual stress conditions of the structure. The fractional factorial design technique shows that the welding current (I) and voltage (V) are statistically significant controlling parameters in the welding process. The results of the neutron diffraction (ND) tests reveal that there is a high concentration of residual stresses close to the weld centre-line. These stresses subside with increasing distance from the centre-line. The resultant hoop residual stress distribution shows that the hoop stresses are highly tensile close to the weld centre-line, decrease in magnitude as the distance from the weld centre-line increases, then decrease back to zero before changing direction to compressive further away from the weld centre-line. The hoop stress distribution profile on the flange side is similar to that of the pipe side around the circumferential weld, and the residual stress peak values are equal to or higher than the yield strength of the filler material. The weld specimens failed at the weld toe where the hoop stress was generally highly tensile in most of the welded specimens. The multiobjective genetic algorithm is successfully used to produce a set of optimal solutions that are in agreement with values obtained during experiments. The 3D finite element model produced using MSC Marc software is generally comparable to physical experimentation. The results obtained in the present study are in agreement with similar studies reported in the literature

NASA Space Engineering Research Center for utilization of local planetary resources

Because of a change in the NASA funding cycle, the present reporting period covers only the six months from March to September 1991. Nevertheless, remarkable progress was made in a number of areas, some of the most noteworthy of which are: (1) Engineering operation of a breadboard CO2 yields O2 demonstration plant that produced over 10 grams of oxygen per day during several runs of over 100 hours each with a single electrolytic cell. Complete automation of controls, monitoring of various inputs/outputs and critical internal variables, diagnostics, and emergency shutdown in an orderly manner were also included. Moreover, 4-cell and 16-cell units, capable of much higher rates of production, were assembled and tested. (2) Demonstration of a 200 percent increase in the carbothermal reduction of ilmenite through vapor deposition of carbon layers on particles of that material. (3) Demonstration of the deposition of strong iron films from carbonyl chemical vapor deposition, establishing the crucial role of additive gases in governing the process. (4) Discovery of an apparent 800 percent increase in the conversion rates of a modified ilmenite simulant in a plasma-augmented reactor, including direct enhancement by solar radiation absorption. (5) Proof that test specimens of lunar soil with small amounts of metallic additives, recrystallized at moderate temperatures, exhibit an improvement of several orders of magnitude in ductility/tensile strength. (6) Experiments establishing the feasibility of producing silicon-based polymers from indigenous lunar materials. (7) Application of CCD technology to the production of maps of TiO2 abundance, defining primary ilmenite deposits, on the disk of the full moon. (8) Attainment of a discovery rate of approximately 3 new near-Earth asteroids per month by Spacewatch, more than doubling the previous global rate. (9) Coordination of industry and university magma electrolysis investigations in a workshop designed to define remaining problem areas and propose critical experiments

Latest Advancements in Micro Nano Molding Technologies – Process Developments and Optimization, Materials, Applications, Key Enabling Technologies

Micro- and nano-molding technologies are continuously being developed due to enduring trends like increasing miniaturization and higher functional integration of products, devices, and systems. Furthermore, with the introduction of higher performance polymers, feedstocks, and composites, new opportunities in terms of material properties can be exploited, and, consequently, more micro-products and micro/nano-structured surfaces are currently being designed and manufactured.Innovations in micro- and nano-molding techniques are seen in the different processes employed in production (injection molding, micro injection molding, etc.); on the use of new and functional materials; for an ever-increasing number of applications (health-care devices, micro-implants, mobility, and communications products, optical elements, micro-electromechanical systems, sensors, etc.); in several key enabling technologies that support the successful realization of micro and nano molding processes (micro- and nano-tooling technologies, process monitoring techniques, micro- and nanometrology methods for quality control, simulation, etc.) and their integration into new manufacturing process chains.This Special Issue reprint showcases research papers and review articles that focus on the latest developments in micro-manufacturing and key enabling technologies for the production of both micro-products and micro-structured surfaces

Effect of Pulsed Current Micro Plasma Arc parameters on weld bead geometry of AISI 316Ti Austenitic Stainless Steel

Micro Plasma Arc Welding (MPAW) is one of the important arc welding system normally using in sheet metal enterprise for production metal bellows, metallic diaphragms and so forth. Inside the present work Pulsed present day Micro Plasma Arc Welding is used for becoming a member of 0.three mm thick Austenitic stainless-steel sheets of AISI 316 Ti. peak contemporary, Base modern, Pulse rate and Pulse Width are taken into consideration as input parameters and weld bead geometry parameters namely front width, lower back width, front peak, lower back peak are taken into consideration as output responses. Response surface approach (RSM) with box-Benhken design is adopted and for 4 factors and three level, total 27 experiments are completed. Weld bead geometry parameters particularly front width, returned width, the front height and lower back top are measured the use of metallurgical microscope. Empirical mathematical models are evolved using statistical software. Analysis of Variance (ANOVA) is executed at ninety five% self belief degree. Predominant and interplay outcomes are studied. Scatter plots are attracted to apprehend the version of actual and predicted values of weld bead parameters

Artifacting Identity. How Grillz, Ball Gags and Gas Masks Expand the Face

By questioning the attribution of a primary role to the eyes as bearers of identity within traditional Western culture, this paper will problematize the agentivity performed by the lower mereology of the face, identified with the mouth-nose assemblage. In particular, the study will focus on the manipulation of such facial spatiality through the intervention of three “lower face” artifacts: the grill, the ball gag and the gas mask. This piece of work will examine their plastic and figurative dimensions in the technological interaction with the facial organs. Furthermore, we will take into consideration the sociocultural context of wearability performed by the different bearers with the aim of grasping the identity shift that the artifacts trigger. The study, therefore, will organize the corpus as a sequence that starts inside the oral cavity where the grill is worn; then moves to a progressive exteriority with the ball gag that emerges from the mouth through the straps fastened around the head; eventually dealing with the exterior projection operated by the gas mask which by means of its filters portends beyond the anatomical face. Ultimately the three artifacts are presented as a threefold articulation of a liminal agency towards an expanded form of humanity including animality embedded within and without the space of meaning represented by the face

NASA Space Engineering Research Center for Utilization of Local Planetary Resources

In the processing of propellants, volatiles, and metals subject area, the following topics are discussed: reduction of lunar regolith; reduction of carbon dioxide; and reduction of carbonaceous materials. Other areas addressed include: (1) production of structural and refractory materials; (2) resource discovery and characterization; (3) system automation and optimization; and (4) database development. The majority of these topics are discussed with respect to the development of lunar and mars bases. Some main topics of interest include: asteroid resources, lunar resources, mars resources, materials processing, construction materials, propellant production, oxygen production, and space-based oxygen production plants

Development of quality assurance procedures and methods for the CBM Silicon Tracking System

The Compressed Baryonic Matter (CBM) experiment at the future Facility for Antiproton and Ion Research (FAIR) aims to study the properties of nuclear matter at high net-baryon densities and moderate temperatures. It is expected that, utilizing ultra-relativistic heavy-ion collisions, a phase transition from hadronic matter to QCD matter will be probed. Among the key objectives are the determination of the nature and order of the transition (deconfinement and/or chiral) and the observation of a critical end-point. To measure and determine the physics phenomena occurring in these collisions, appropriate detectors are required. The Silicon Tracking System (STS) is the key detector to reconstruct charged particle tracks created in heavy-ion collisions. In order to assure the necessary detector performance, about 900 silicon microstrip sensors must be checked and tested for their quality. For these tasks highly efficient and highly automated procedures and methods have to be developed. The first part of this dissertation reports on a novel automated inspection system developed for the optical quality control of silicon microstrip sensors. Proposed methods and procedures allow to scan along the individual sensors to recognize and classify sensor defects. Examples of these defects are: surface scratches, implant defects, metalization layer lithography defects and others. In order to separate and classify these defects various image-processing algorithms based on machine vision are used. The silicon sensors are also characterized geometrically to ensure the mechanical precision targeted for the detector assembly procedures. Since the STS detector will be operated in a high radiation environment with a total non-ionizing radiation dose up to 1x10^14 n_eq/cm^2 over 6 years of operation, the silicon sensors need to be kept in the temperature range of -5 to -10 °C at all times to minimize reverse annealing effects and to avoid thermal runaway. The second part of this work is devoted to the development and optimization of the design of cooling bodies, which remove the thermal energy of overall more than 40 kW produced by the front-end readout electronics. In particular, thermodynamical models were developed to estimate the cooling regimes and thermal simulations of the cooling bodies were carried out. Based on the performed calculations an innovative bi-phase CO2 cooling system of up to 200 W cooling power was built and allowed to verify the simulated cooling body designs experimentally.In der geplanten Experimentieranlage für Antiprotonen- und Ionenforschung (Facility for Antiproton and Ion Research, FAIR) wird das Compressed Baryonic Matter Experiment (CBM) nukleare Materie bei hoher Baryonendichte und moderaten Temperaturen untersuchen. Der Phasenübergang zwischen hadronischer und QCD-Materie kann mithilfe von ultrarelativistischen Schwerionenkollisionen untersucht werden. Die wichtigsten Ziele sind die Bestimmung der Art des Übergangs (Deconfinement- und/oder chiraler Phasenübergang) und die Untersuchung des kritischen Endpunktes im Phasendiagramm. Um diese Phänomene zu untersuchen, sind geeignete Detektorsysteme notwendig. Das Silicon Tracking System (STS) ist der zentrale Detektor, mit Hilfe dessen die Spuren der in den Schwerionenkollisionen erzeugten geladenen Teilchen rekonstruiert werden. Um die volle Funktionsfähigkeit des STS sicherzustellen, müssen die mehr als 900 Siliziumstreifensensoren vor dem Zusammenbau überprüft und getestet werden. Hierfür müssen die hocheffiziente und automatisierte Prozeduren und Methoden entwickelt werden. In erstem Teil dieser Dissertation wird über ein automatisiertes optisches Inspektionssystem berichtet. Das System erlaubt es, die einzelnen Siliziumsensoren auf potentielle vorhandene Oberflächendefekte zu untersuchen und sie zu klassifizieren. Beispiele hierfür sind: Kratzer auf der Oberfläche, Implantierungsdefekte oder Lithographiedefekte der Metallisierungsschicht. Für das Erkennen dieser Defekte werden mehrere “Machine Vision” Bildbearbeitungsalgorithmen benutzt. Außerdem werden die geometrischen Parameter der Sensoren, die für den Zusammenbau des STS wichtig sind, optisch kontrolliert. Der STS Detektor wird bei extrem hohen Kollisionsraten betrieben. Innerhalb einer Betriebsbszeit von 6 Jahren wird eine Strahlungsdosis von bis zu 1x10^14 n_eq/cm^2 akkumuliert, was zu einer deutlichen Erhöhung des Dunkelstrom führt und letztlich des “end-of-life” Kriterium darstellt. Die Siliziumsensoren müssen deswegen auf -5 bis -10 °C gekühlt werden, um “reverse Annealing” Effekte zu minimieren und das “Thermal Runaway” Phänomen zu verzögern. Durch die Ausleselektronik werden andererseits mehr als 40 kW an thermischer Energie nahe der Sensoren produziert, die deshalb mit Kühlkörpern komplett abgeleitet werden muß. Das zweite Teil dieser Dissertation wurde der Optimierung von Kühlkörpern gewidmet. Dafür wurden thermodynamische Modelle implementiert und entsprechende thermische Simulationen durchgeführt. Im Rahmen der Arbeit wurde ein 200 W CO2 Kühlungssystem gebaut, das es erlaubt, die Modellberechnungen und Simulationen einer Kühlung mit 2-phasigem CO2 zu überprüfen