Deep residual learning in CT physics: scatter correction for spectral CT

Recently, spectral CT has been drawing a lot of attention in a variety of clinical applications primarily due to its capability of providing quantitative information about material properties. The quantitative integrity of the reconstructed data depends on the accuracy of the data corrections applied to the measurements. Scatter correction is a particularly sensitive correction in spectral CT as it depends on system effects as well as the object being imaged and any residual scatter is amplified during the non-linear material decomposition. An accurate way of removing scatter is subtracting the scatter estimated by Monte Carlo simulation. However, to get sufficiently good scatter estimates, extremely large numbers of photons is required, which may lead to unexpectedly high computational costs. Other approaches model scatter as a convolution operation using kernels derived using empirical methods. These techniques have been found to be insufficient in spectral CT due to their inability to sufficiently capture object dependence. In this work, we develop a deep residual learning framework to address both issues of computation simplicity and object dependency. A deep convolution neural network is trained to determine the scatter distribution from the projection content in training sets. In test cases of a digital anthropomorphic phantom and real water phantom, we demonstrate that with much lower computing costs, the proposed network provides sufficiently accurate scatter estimation

Satisfaction of Sanitation Services in Uttar Pradesh with Special Reference to Gorakhpur District of Uttar Pradesh, India

Sanitation is one of the most important aspect for an individuals and also good for the healthy life, and protection from the various diseases. To achieved the complete cleanness in the country, the central and state governments are jointly operating the sanitation related services in the state. This study is an attempt to assess the satisfaction level from the sanitation services in Gorakhpur district of Uttar Pradesh. For this purpose, 285 sample have been selected randomly in both rural (165) and urban (120) habitants of the district. The satisfaction of sanitation services has been measured with respect to three variables that are gender, habitat, and community. For the analysis of data, a descriptive statistics techniques such as Mean, Standard Deviation and ANOVA, have been used. After careful analysis of data, one can find out that the female population (Grand Mean = 8.0446) are less satisfied with sanitation service as compared to male population (Grand Mean = 9.2656). It is also revealed from the data analysis that urban population (Grand Mean = 11.8500) are satisfied with sanitation services as compared to rural population (Grand Mean = 6.2242) of the district. Therefore, the findings of the study advises that a suitable mechanism must be require or available ones need to more straighten to monitored on the sanitation services in rural areas of the district and for better sanitation services government should encourage a women’s self-help group to participate in it

Flame Retardant Mattress Pads

Focus of this research is on developing cotton-based nonwoven mattress pads with flame retardant (FR) properties by blending cotton with other commercially available fibers, binders, and followed by chemical treatments; offering a cost-effective recipe to meet the upcoming flammability standards. Furthermore this research explores the opportunities taking advantage of possible synergistic effects to achieve maximum performance. Recent changes in the flammability regulations require improvements in the flame resistance of cotton-containing consumer goods such as upholstered furniture, mattresses, and pillows. Cotton, synthetic fibers, fabrics, and foam are the basic constituents of these goods that are often the first to be engulfed by fire. Hence there is a need to impart certain degree of flame resistance based on their end use. In case of real fires, these improvements in flame retardancy would provide more time for people to escape from a fire with fewer injuries, and result in savings of life as well as property. Cotton being a highly flammable fiber, to achieve higher degree of flame resistance, it is necessary to incorporate additional fibers and chemicals into cotton products. Choice of appropriate materials can help to achieve a synergistic role in the combustion process to slow down burning, reduce flame spread, or even extinguish the fire. Many of these chemicals are expensive and lead to a spike in the product cost. Moreover there are certain FR chemicals that are likely to pose environmental and health hazards. The FR chemicals used in this research are halogen free and have been considered safe. Finally, a cost effective recipe for constructing mattress pads that passes the latest flammability tests was developed. As planned, these nonwoven pads were produced by blending cotton with other commercially available fibers, binders, and followed by chemical treatments that take advantages of various synergistic effects to achieve maximum performance at low cost. The product of this research is a good candidate for mattress pads as well as other products such as upholstered furniture, mattress ticking, and pillows, which are required to comply with the open flame standards

Processing and Evaluation of Cotton-based Composites for Automotive and Other Applications

Fiber reinforced composites (FRCs) have been used for a long time in structural and semi-structural applications. FRCs have the advantage of lightweight and best property performance compared to traditional materials such as metals. In several instances, disposability of such products becomes a major issue. There has been increasing demand for use of recyclable and or biodegradable composites for automotives, especially due to the recent European Union directives. With the growth of automobiles in the global market, and a simultaneous pressure to address the issue of sustainability, there is continual need for the incorporation of natural fiber based materials into automotives. The focus of this research has been to produce biodegradable cotton fiber-based composites that can be safely disposed off after their intended use without polluting the atmosphere, in an environmentally safe manner. This research deals with cotton-based nonwovens using blends of cotton, flax, kenaf and a biodegradable thermoplastic fiber. Biomax®, Polylactic Acid (PLA), Polyvinyl Acetate (PVAc), and Eastar®bio-copolyester (PTAT) are the chosen thermoplastic fibers that could function as the binders, thus eliminating the use of any non-biodegradable synthetic fiber such as Polypropylene (PP) or a chemical binder. The process involves the fabrication of nonwovens from blends of fibers in different proportions made by air laying or carding to form webs, molding these webs into composites, and subsequent characterization of the composites for their properties such as tensile strength, flexural strength, and acoustic properties. Results from these studies addressing the structure and properties of the composites, contribution from individual constituents, with respect to their suitability for automotive applications are discussed. Basic studies on structure and properties of fibers showed the ability of these natural fibers to form a good bond between thermoplastic polymer such as Eastar, Biomax, and Cellulose Acetate. Fiber bonding studies reinforced this observation. Comparison of Sandwich type composites with Fiber mix type composites showed that the bonding between natural fibers and the binder polymer is better when composites are made from mixed fiber webs. Furthermore, intimate blending is the key to make a composite with good properties. Biodegradable composites were developed from air laid webs of natural fibers (cotton, flax, and kenaf) and binder fibers (Biomax, PLA, and PVAc) by thermal bonding in a hot press. It proved that blending of flax and kenaf increases the tensile strength of the cotton composites. Further, Three point bending test showed that PLA based cotton composites have slightly lower flexural strength compared to conventional PP. Adding about 10% kenaf or flax increases flexural strength substantially, indicating that kenaf and flax act like stiffeners. Acoustics properties of the composites measured by Four point Impedance Tube method showed that blending kenaf or flax increases noise absorption quality of cotton-PLA composites. Notched Izod impact tests showed that the impact strength of PLA and PLAbico binders is higher than that of PP. Moreover blending kenaf or flax increases the impact strength of the composites substantially. Impact strength increases as the composite thickness is raised keeping same basis weight. Comparison of binders, Biomax, PLA, and PVAc fibers in a natural fiber composite showed that PVAc provides more tensile strength and elongation to the cotton or flax rich composite, where as PLA performs similarly in kenaf rich composites. Biomax performance is very close to that of PVAc. In other words, PVAc and Biomax form better composites with cotton and flax than PLA. If PVAc stands out for its superior performance in composites containing more cotton or flax, PLA stands out for the similar performance at lower curing temperature that reduces the bad odor in composites and has processing conditions close to conventional PP. The main advantage of Biomax is its lower cost compared to both PLA and PVAc. Process optimization studies showed that there is an optimum bonding temperature and optimum-curing time for composites. Tensile strength increases as the curing pressure or basis weight/ thickness increases. Increase in tensile strength achieved by blending kenaf or flax (even at 10% level) is substantial. However there is marginal drop in elongation. Further on the basis of these studies, it is expected that viable composite parts containing cotton and other natural fibers can be produced with a thermoplastic binder fiber, that are biodegradable and possess the required properties that are comparable to the traditional polypropylene based composites. Such composites are suitable for automotive and many other semi-structural applications

Child soldiers in transition: A gender aware case study of Maoist young adults in Nepal

This short research paper is an attempt to explore the involvement of girls in the Nepal Maoist war, the push factor, and their empowerment during their association with the Maoist. It also looks at the rights perspective and the conscious decisions taken by the young combatants to join the Maoist to fight for the cause of equality and justice. Contrary to the common outlook of girl soldiers as victims of forced recruitment, abduction and abuse, the paper looks at the voluntary recruitment as expression of agency in the light of a conflict situation where the systems are not geared towards taking care of their needs and rights. The paper draws on interviews from ex-combatants and NGO/INGO personnel and analyses them to get a understanding of their involvement and their present life post the signing of the peace accord

Micromechanical high-Q trampoline resonators from strained crystalline InGaP for integrated free-space optomechanics

Tensile-strained materials have been used to fabricate nano- and micromechanical resonators with ultra-low mechanical dissipation in the kHz to MHz frequency range. These mechanical resonators are of particular interest for force sensing applications and quantum optomechanics at room temperature. Tensile-strained crystalline materials that are compatible with epitaxial growth of heterostructures would thereby allow realizing monolithic free-space optomechanical devices, which benefit from stability, ultra-small mode volumes and scalability. In our work, we demonstrate micromechanical resonators made from tensile-strained InGaP, which is a crystalline material that can be epitaxially grown on III-V heterostructures. The strain of the InGaP layer is defined via its Ga content when grown on (Al,Ga)As. In our case we realize devices with a stress of up to 470\,MPa along the $[1\,1\,0]$ crystal direction. We characterize the mechanical properties of the suspended InGaP devices, such as anisotropic stress, anisotropic yield strength, and intrinsic quality factor. We find that the latter degrades over time. We reach mechanical quality factors surpassing $10^7$ at room temperature with a $Q\cdot f$-product as high as $7\cdot10^{11}$ with trampoline-shaped micromechanical resonators, which exploit strain engineering to dilute mechanical dissipation. The large area of the suspended trampoline resonator allows us to pattern a photonic crystal to engineer its out-of-plane reflectivity in the telecom band, which is desired for efficient signal transduction of mechanical motion to light. Stabilization of the intrinsic quality factor together with a further reduction of mechanical dissipation through hierarchical clamping or machine learning-based optimization methods paves the way for integrated free-space quantum optomechanics at room temperature in a crystalline material platform.Comment: fixed typos, added more material on crystal anisotropy and on fabrication; 15 pages incl. appendix, 13 figure

Vision Encoder-Decoder Models for AI Coaching

This research paper introduces an innovative AI coaching approach by integrating vision-encoder-decoder models. The feasibility of this method is demonstrated using a Vision Transformer as the encoder and GPT-2 as the decoder, achieving a seamless integration of visual input and textual interaction. Departing from conventional practices of employing distinct models for image recognition and text-based coaching, our integrated architecture directly processes input images, enabling natural question-and-answer dialogues with the AI coach. This unique strategy simplifies model architecture while enhancing the overall user experience in human-AI interactions. We showcase sample results to demonstrate the capability of the model. The results underscore the methodology's potential as a promising paradigm for creating efficient AI coach models in various domains involving visual inputs. Importantly, this potential holds true regardless of the particular visual encoder or text decoder chosen. Additionally, we conducted experiments with different sizes of GPT-2 to assess the impact on AI coach performance, providing valuable insights into the scalability and versatility of our proposed methodology.Comment: 6 pages, 2 figure

Optomechanical cooling with coherent and squeezed light: the thermodynamic cost of opening the heat valve

Ground-state cooling of mechanical motion by coupling to a driven optical cavity has been demonstrated in various optomechanical systems. In our work, we provide a so far missing thermodynamic performance analysis of optomechanical sideband cooling in terms of a heat valve. As performance quantifiers, we examine not only the lowest reachable effective temperature (phonon number) but also the evacuated-heat flow as an equivalent to the cooling power of a standard refrigerator, as well as appropriate thermodynamic efficiencies, which all can be experimentally inferred from measurements of the cavity output light field. Importantly, in addition to the standard optomechanical setup fed by coherent light, we investigate two recent alternative setups for achieving ground-state cooling: replacing the coherent laser drive by squeezed light or using a cavity with a frequency-dependent (Fano) mirror. We study the dynamics of these setups within and beyond the weak-coupling limit and give concrete examples based on parameters of existing experimental systems. By applying our thermodynamic framework, we gain detailed insights into these three different optomechanical cooling setups, allowing a comprehensive understanding of the thermodynamic mechanisms at play.Comment: 28 pages, 14 figures, 2 tables Small revision of the main text, corrected typos in the appendices, added study of the stability of the systems and comparison with absorption refrigerators in appendi

Solid Source Metal-Organic Molecular Beam Epitaxy of Epitaxial RuO2

A seemingly simple oxide with a rutile structure, RuO2 has been shown to possess several intriguing properties ranging from strain-stabilized superconductivity to a strong catalytic activity. Much interest has arisen surrounding the controlled synthesis of RuO2 films but, unfortunately, utilizing atomically-controlled deposition techniques like molecular beam epitaxy (MBE) has been difficult due to the ultra-low vapor pressure and low oxidation potential of Ru. Here, we demonstrate the growth of epitaxial, single-crystalline RuO2 films on different substrate orientations using the novel solid-source metal-organic (MO) MBE. This approach circumvents these issues by supplying Ru using a pre-oxidized solid metal-organic precursor containing Ru. High-quality epitaxial RuO2 films with bulk-like room-temperature resistivity of 55 micro-ohm-cm were obtained at a substrate temperature as low as 300 C. By combining X-ray diffraction, transmission electron microscopy, and electrical measurements, we discuss the effect of substrate temperature, orientation, film thickness, and strain on the structure and electrical properties of these films. Our results illustrating the use of novel solid-source MOMBE approach paves the way to the atomic-layer controlled synthesis of complex oxides of stubborn metals, which are not only difficult to evaporate but also hard to oxidize.Comment: 21 pages including 6 figure