Titanium carbide coatings for aerospace ball bearings

In conventional ball bearings, steel to steel contacts between the balls and the raceways are at the origin of microwelds which lead to material transfer, surface roughening, lubricant breakdown, and finally to a loss in the bearing performances. To minimize the microwelding tendencies of the contacting partners it is necessary to modify their surface materials; the solid to solid collisions themselves are difficult to avoid. The use of titanium carbide coated steel balls can bring spectacular improvements in the performances and lifetimes of both oil-grease lubricated and oil-grease free bearings in a series of severe applications

Wear-resistant ball bearings for space applications

Ball bearings for hostile environments were developed. They consist of normal ball bearing steel parts of which the rings are coated with hard, wear-resistant, chemical vapor deposited (C.V.D) TiC. Experiments in ultrahigh vacuum, using cages of various materials with self-lubricating properties, have shown that such bearings are suitable for space applications

Opportunity to Test non-Newtonian Gravity Using Interferometric Sensors with Dynamic Gravity Field Generators

We present an experimental opportunity for the future to measure possible violations to Newton's 1/r^2 law in the 0.1-10 meter range using Dynamic gravity Field Generators (DFG) and taking advantage of the exceptional sensitivity of modern interferometric techniques. The placement of a DFG in proximity to one of the interferometer's suspended test masses generates a change in the local gravitational field that can be measured at a high signal to noise ratio. The use of multiple DFGs in a null experiment configuration allows to test composition independent non-Newtonian gravity significantly beyond the present limits. Advanced and third-generation gravitational-wave detectors are representing the state-of-the-art in interferometric distance measurement today, therefore we illustrate the method through their sensitivity to emphasize the possible scientific reach. Nevertheless, it is expected that due to the technical details of gravitational-wave detectors, DFGs shall likely require dedicated custom configured interferometry. However, the sensitivity measure we derive is a solid baseline indicating that it is feasible to consider probing orders of magnitude into the pristine parameter well beyond the present experimental limits significantly cutting into the theoretical parameter space.Comment: 9 pages, 6 figures; Physical Review D, vol. 84, Issue 8, id. 08200

Synthetic CT generation for radiotherapy treatment planning using deep learning

LAUREA MAGISTRALELa generazione di immagini TC sintetiche rappresenta un'importante sfida nel contesto della radioterapia basata solo su risonanza magnetica (MRI-only), in quanto l'obiettivo è ridurre la dipendenza dalle tradizionali immagini TC. Questa tesi indaga l'applicazione e l'efficacia del framework Pix2Pix, un GAN condizionale, per la traduzione delle immagini MRI cerebrali nelle corrispondenti TC sintetiche. Lo studio esplora diverse tecniche di preparazione dei dati, tra cui i formati a 8-bit e 16-bit, le modalità a colori RGB e un approccio 2.5D, per determinare il metodo più efficace per generare immagini sintetiche di alta qualità. Metodi di valutazione come l'Errore Quadratico Medio (MSE), il Rapporto Segnale-Rumore di Picco (PSNR) e la Misura dell'Indice di Somiglianza Strutturale (SSIM) vengono utilizzati per valutare sia la fedeltà dell'immagine sia la precisione strutturale. Inoltre, le immagini TC sintetiche sono ulteriormente valutate utilizzando un algoritmo di segmentazione per isolare e analizzare le strutture anatomiche. Infine, viene condotta un'analisi comparativa confrontando i risultati con la classifica synthRAD2023. I risultati rivelano che l'uso di un approccio 2.5D migliora notevolmente la qualità delle ricostruzioni sintetiche e la precisione strutturale. Questo suggerisce che approcci geometrici basati su patch 3D possano migliorare la continuità spaziale e ridurre utleriormente gli errori nelle immagini TC sintetiche generate.The generation of synthetic CT images is a critical challenge in the context of MRI-only radiotherapy, which aims to reduce the reliance on traditional CT imaging. This thesis investigates the application and the effectiveness of the Pix2Pix framework, a conditional GAN, for translating brain MRI images into their corresponding synthetic CTs. The study explores various data preparation techniques, including 8-bit and 16-bit formats, RGB color modes, and a 2.5D model approach, to determine the most effective method for generating high-quality synthetic images. Metrics evaluation such as Mean Squared Error (MSE), Peak Signal-to-Noise Ratio (PSNR), and Structural Similarity Index Measure (SSIM) are employed to assess both image fidelity and structural accuracy. Additionally, synthetic CT images are further evaluated using a segmentation algorithm to isolate and analyze anatomical structures. A comparative analysis is conducted by benchmarking the results against the synthRAD2023 challenge leaderboard. The results reveal that the use of stacked 16-bit grayscale slices, yield the best image quality and structural accuracy. It suggests that 3D patch-based geometrical approaches can possibly enhance spatial continuity and further reduce errors in the generated synthetic CT images

Ciliate Endosymbiont Imaging Methodology

Ciliates, a phylum of diverse microbial eukaryotes, are found in a wide range of environments, including anoxia. Anaerobic ciliates host intracellular methanogenic archaea – a unique type of symbiosis. Despite their importance, anaerobic ciliates and their symbiotic relationships remain understudied. Included in this is the ability to image and quantify the intracellular methanogenic symbionts in a precise, timely and replicable procedure. This project aimed to improve the current fluorescence microscopy methodology used for endosymbiont quantification. The proposed method is intended for use with the Opera Phenix, a high throughput spinning disk confocal microscope which can count large amounts of individual cells automatically. Cells obtained from anaerobic cell cultures were fixed in paraformaldehyde, washed, and filtered before imaging. The findings of the study indicate that the method developed has potential. A challenge that remains is removing fine debris from the sample that interfere with automatic cell counting, while ensuring high ciliate concentrations that can be quantified. Once this challenge is addressed, the method developed could aid in gaining new insights into the complex relationship between ciliates and their endosymbionts

Pillaithamil Texts by Tamizhkuzhavi

Literary genres in the context of Tamil literature have varied from time to time. A poet Tamilkuzhavi who is making a great achievement in the 21st century in Pillaithamil poetry. Pillaithamil has written the lives of saints who have done charity in Tamil Nadu as literature. Tamilkuzhavi was a poet who wrote about Pillaittamil, one of the minor literary genres in Tamil literature. Pillaithamil sings social activist leaders to make the world aware of their pride. Care and Protect prays for the leaders who strive to eradicate the injustices occurring in the society during the first season of the ten seasons. But it can be seen through this article that the poet presents Bharat Mata, Thirukkural, Tamilannai, Parasakthi and Alvars as deities that come through the tradition of Tamil women

Depictions of Society in Arumugam Novel by Imaiyam

The reason Tamil literature is called folk literature is that it portrays the real life of the people living in the society. The novel is based on a broad base of Tamil literature. Tamil literature has been created by different authors in different eras and the reason why it is outstanding even today is because of writing the problems happening in the society in their language. Socially oriented novels are a huge hit with people. In the novels of the centre, he has expressed ideas such as social inequality, economic problems, oppressive methods and humanistic thoughts in the novels. Society has various norms, customs and traditions. Imaiyam has told in the novel Arumugam that every person in the society is facing problems every day. This article examines the problems faced by the family after the death of the father who has to take care of the family. The author has realistically created the present day social environment in the novel Arumugam with the depiction of the society

An Innovative Approach to Tracking Sediment Transport along Roads

A study of sediment transport was carried out in the New England area of the United States where large quantities of sediments and other debris accumulate along roads. These sediments are mostly transported by roadway runoff and stormwater drainage structures, where present, tend to concentrate them. However, polluted sediments might also find their way into ecologically sensitive areas. Our research aimed at tracking the transport of these sediments as they move along a road. Further, we attempted to quantify the rate by which the sediments were transported. Glass microbeads in the size range of sand were released as a tracer of sediment transport at six comparable locations. Over a period of 10 months, their movement was tracked using microscopy. Our results indicate that this type of tracer was successful in following along the sediment transport. More research is required to establish this new method under different stormwater runoff regimes or different roadside maintenance conditions

Permeability analysis in bisized porous media: wall effect between particles of different size

The permeability of binary packings of glass beads with different size ratio – 13.3, 20, and 26.7, was investigated. In the Kozeny–Carman equation, the dependence of the tortuosity τ on the mixture porosity ε(xD) was described according to τ = 1/εn for different volume fraction of large particles in the mixture, xD. Obtained data on packing permeability shows that the parameter n is a function of the volume fraction and particle size ratio, with values between 0.5 and 0.4. This can be explained by the wall effect resulting from the arrangement of the small particles occurring near the large particle surface. A model taking in account this effect was suggested that can be useful in the characterization of transport phenomena in granular beds as well as in engineering applications.Fundação para a Ciência e a Tecnologia (FCT) - SFRH/BPD/18128/2004; Project POCI_EQU_58337/2004

Induced Bank Filtration: Hydraulic Testing of Pilot Filters

Hydraulic tests were performed on two pilot scale filters as part of a water treatment project in the village of Nersa, Karnataka, India. The filters use locally sourced alluvial material to filter E.coli contamination using natural processes that mimic those in Riverbank Filtration (RBF). Two pilot scale filters were tested, one containing locally sourced granular activated carbon (GAC) and one without. A falling head test and tracer test were preformed, and breakthrough curves were used to analyze the hydraulic performance. E.coli data were also collected, and percent removal was calculated to determine the effectiveness of the filters. Relative to the influent water, the E.coli removal percentage of Filter 1 (no GAC) was consistently high and ranged between 97.1% and 100% E.coli. The addition of GAC did not improve performance in this study. Overall, the effectiveness in bacteria removal observed in the non GAC filter warranted construction of a full-scale system