3,260 research outputs found

    Dirac-Maxwell correspondence: Spin-1 bosonic topological insulator for light

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    Fundamental differences between fermions and bosons are revealed in their spin and distribution statistics as well as the discrete symmetries they obey (charge, parity and time). While significant progress has been made on fermionic topological phases of matter with time-reversal symmetry, the bosonic counterpart still remains elusive. We present here a spin-1 bosonic topological insulator for light by utilizing a Dirac-Maxwell correspondence. Departing from structural photonic approaches which mimic the pseudo-spin-\textonehalf{} behavior of electrons, we exploit the integer spin and discrete symmetries of the photon to formulate a distinct bosonic topological phase of matter. We introduce a bosonic Kramers theorem and the photonic equivalent of topological quantization, which arises solely from photon spin. Our continuum field theory predicts that photons acquire a mass in the presence of a spatio-temporally dispersive degenerate chirality, a unique form of magneto-electric coupling inside matter fundamentally different from well-known chirality, magneto-electricity, gyrotropy or bi-anisotropy. We predict that this unique dispersive (non-local) degenerate chiral medium has anomalous parity and time-reversal symmetries and if found in nature will exhibit a gapped Quantum spin-1 Hall bosonic phase. Photons do not possess a conductivity transport parameter which can be quantized (unlike electronic systems), but we predict that photon spin quantization of symmetry-protected edge states is amenable to experimental isolation leading to a new bosonic phase of matter.Comment: 13 pages, 4 figure

    Outpatient Physical Therapy Rehabilitation of a Patient with Ehlers-Danlos Syndrome and Received a Total Knee Arthroplasty

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    Background and Purpose. Total knee arthroplasties (TKA) remain the gold standard of surgical interventions to the knee and are often used to treat the knee joint for arthritic changes along with therapeutic exercise. Case Description. This case report describes the physical therapy rehabilitation of a 48-year-old female post left T KA due to increased instability, afthritic changes, and pain caused by her EDS combined with her high BMI. The patient previously had her right knee replaced with a TKA and was acquainted with the rehabilitation process and familiar with all of the therapeutic exercises and proper progression of her activity. Intervention. The treatment of this patient included physical therapy intervention consisting of therapeutic exercises, gait training, manual therapy, electrical stimulation, ultrasound/phonophoresis, low-level laser therapy, and KinesioTaping. Outcomes. The patient had multiple episodes of exacerbated symptoms lasting for weeks and likely caused damage to the surrounding tissue around her left knee from acute injuries that slowed her recovery. The patient required multiple weeks of therapeutic modalities to control her symptoms. She also had physician\u27s orders not to complete any strengthening exercises whatsoever in order to allow for healing. After the patient was cleared for light strengthening exercises, she progressed rapidly and was soon confident enough to discontinue therapy and progress her strengthening on her own. Discussion. Rationale for treatment was based on total knee arthroplasty protocols with special considerations made due to the patient\u27s diagnosis of EDS as well as her physician\u27s guidelines for treatment and the patient\u27s symptoms

    Mechanochemical Synthesis of Fuels from Sustainable Sources Utilizing Solid Catalysts

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    Mechanochemistry requires less solvents which results in less waste generation. The question becomes can we apply mechanochemistry to current chemical reactions and reduce the generation of waste. This process can be simple or can be very extensive resulting in the generation of large amounts of waste and very little product. A significant advantage of mechanochemistry is the reduced need for solvents that would be common place for reactions. Mechanochemistry transfers energy to reagents via impacts from milling media. Energy can be transferred to the reagents no matter their state-of-matter. Much of the current studies in mechanochemistry today are done using reagents in their solid-state, organic or inorganic compounds. Mechanochemistry is not limited to just solid-state, reactions in liquid-state and even gas-state are possible to utilize for reagents. The transition to biofuels as a means of curbing the emissions of greenhouse gases has given rise to several questions such as what to use as the feedstock and which process is most costefficient. Chapter 2 of this research focused on another question that being the interactions between biofuels and different materials. This research performed a long-term study on the interaction between polymers and biofuels. Similar research has been conducted, but where the difference lies is that the polymer selected was given shape, o-ring, to perform a specific function, stop leaks. What was observed is that after prolonged exposure to biofuels the o-ring decreased in volume, which would result in leaking of fuel. To counter this degradation two different aromatic compounds were tested by dissolving them into the biofuels. With as little as 1% w/w of aromatic compound the decrease in volume observed in the biofuels without aromatic compounds was not observed. Propane is commonly used fuel for heating homes, cooking, to fueling vehicles. Currently the primary source of propane is from oil refining. Chapter 3 of this research details the synthesis of propane from biomasses, that would normally be discarded, utilizing mechanochemistry. The methods used reduced the need for solvents and unlike other methods currently employed to make propane, no toxic materials were generated. The starting material was cassava pulp, a biomass high in cellulose. The cellulose was converted to simple sugars, which were then converted to 1,3-dihydroxyacetone, and then finally converted to propane. Each step of this process was performed mechanochemically, reducing the need for solvent, each catalyst was naturally occurring and easily recyclable. The catalyst used for the conversion to propane was itself synthesized mechanochemically with no solvents required. One aspect of green chemistry is the reduction of waste generation from chemical reactions/process. Another aspect of green chemistry is finding new catalysts that are less environmentally damaging. Mechanochemistry has been proven to reduce the need for solvents, or remove the need all together, and transitioning to solid catalysts can reduce the solvent need to extract the catalyst. Chapter 4 of this research combined mechanochemistry and the use of a solid catalyst for the synthesis of oil of wintergreen, a common esterification reaction. Esterification reactions are common in academia, industry, and pharmacology, and as a result large amounts of solvents are needed for wash and separation steps. Utilizing both mechanochemistry and solid catalysts the amount of solvent can be reduced. Similar to esterification transesterification is a common chemical reaction that is performed in academia, industry, and pharmacology typically catalyzed with bases i.e. sodium hydroxide. The advantage of catalysts such as these is that the reactions are very quick with high yields. The disadvantage to using catalysts such as sodium hydroxide is that they cannot be recycled. Chapter 5 focused on the synthesis of biodiesel, which is commonly synthesized via transesterification of triglycerides with a short-chain alcohol. Transitioning to solid catalysts would allow for the recycling of the catalyst, which would reduce waste generation. Another focus was the transitioning from methanol to ethanol. Fatty acid methyl esters are formed from the transesterification of a triglyceride with methanol and is the more commonly synthesized biodiesel as it requires less energy than longer chain alcohols, thus making it faster as well. However, methanol is toxic to people and the environment, where ethanol is safer. The focus of this research became finding a solid catalyst that would promote transesterification using ethanol as the alcohol via mechanochemistry

    The Logic of Faith

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    Two objects of faith are every-where presented in Scripture, and are implied in this passage, namely: God\u27s promise and God\u27s veracity.https://place.asburyseminary.edu/ecommonsatsdigitalresources/1181/thumbnail.jp

    Archaeological Investigations at Moody Reunion and Fairgrounds, Floresville, Wilson County, Texas

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    Archaeologists from the Center for Archaeological Studies (CAS) at Texas State University conducted an intensive pedestrian survey including the excavation of 5 mechanical trenches and 50 shovel tests in Moody Reunion and Fairgrounds, Floresville, Texas, from January 10 through February 23, 2018. The survey was executed in order to assess the project area for potential impacts to cultural resources in advance of the installation of a new baseball complex and associated infrastructure by the City of Floresville. Work was carried out by CAS archaeologists Jacob Hooge and David Macias under Texas Antiquities Permit Number 8276, assigned to Principal Investigator Jacob Hooge. The area of potential effects (APE) includes Floresville River Park, Kiddie Park, and an area extending approximately 1,400 meters northwest of the Floresville Events Center. Other than modern refuse, only one single prehistoric stone tool was observed in a secondary context within a gully near the San Antonio River. The source of the tool could not be identified leading to its classification as an isolated find, and thus, holds little research value, and are not significant to the city’s, state’s or nation’s history. Although soil profiles observed in trenches and a natural erosion feature exhibit potential for buried archaeology, no other prehistoric or historic cultural materials were observed during survey. Accordingly, CAS recommends full regulatory clearance for the installations of all of the proposed features