Health-care systems in the USA and most of western Europe face challenges in the coordination and integration of care for patients, particularly those with chronic conditions. In response to these problems, interest in the patient-centred medical home (PCMH) model has increased significantly in recent years in the USA, with PCMH implementation underway in a wide variety of practice settings across the country. Despite this enthusiasm, there have been relatively few attempts to examine the empirical evidence on the effects of PCMH on quality and access-related outcomes for patients. This article reviews findings from empirical evaluations of the effects of PCMH on patient-related outcomes and critically examines methodological and conceptual issues in the growing body of PCMH literature. The results of this review suggest that published evaluations are predominantly weighted towards findings that indicate that PCMH is associated with a wide range of positive patient outcomes. However, methodological and measurement issues present in much of this research should be considered when evaluating these findings. The article concludes with recommendations for future PCMH evaluation.

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The increasing heat densities in electronic components and focus on energy efficiency have motivated utilization of embedded two-phase cooling, which reduces system-level thermal resistance and pumping power. To achieve maximum benefit, high heat fluxes and vapor qualities should be achieved simultaneously. While many researchers have achieved heat fluxes in excess of 1 kW/cm2, vapor qualities are often below 10%, requiring a significantly large amount of energy spent on subcooling or pumping power, which minimizes the benefit of using two-phase thermal transport. In this work, we describe our recent work with cooling devices utilizing film evaporation with an enhanced fluid delivery system (FEEDS). The design, calibration, and experimental testing of a press-fit and bonded FEEDS test section are detailed here. Heat transfer and pressure drop performance was characterized and discussed. With the press-fit Si test chip, heat fluxes in excess of 1 kW/cm2 were obtained at vapor qualities approaching 45% and a coefficient of performance (COP) approaching 1400. With the bonded SiC test chip, heat fluxes in excess of 1 kW/cm2 were achieved at a vapor quality of 85% and heat densities approaching 490 W/cm3.

This work presents the design and characterization of a two-phase, embedded manifold-microchannel (MMC) system for cooling of high heat flux electronics. The study uses a thin-Film Evaporation and Enhanced fluid Delivery System (FEEDS) MMC cooler for high heat flux cooling of electronics. The work builds upon our group’s earlier work in this area with a particular focus on the use of an improved bonding structure and implementation of uniform heat flux heaters that collectively contribute to enhanced performance of the system. In many MMC systems targeted for high heat flux applications microchannels and manifolds are fabricated separately due to different dimensions and tolerances required for each. However, assembly of the system often leaves a gap between the channels and the manifold, thus causing the working fluid to leak through the top of the microfins leading to decreased cooler performance. The effect of this gap is parametrized and analyzed with ANSYS Fluent CFD simulations and discussed in this paper. The findings show that even a few microns wide gap can cause a noticeable degradation of the MMC system performance. Imperfect assembly and the deformation of a microchannel chip due to working fluid pressure can cause gaps, indicating the necessity of uniform and hermetic bonding between the manifold and the tips of the microfins. Furthermore, this work presents the need for better heater designs to enable uniform and high heat flux to the heat transfer surface. Serpentine heaters are often used to mimic electronics in a laboratory environment, but there is a lack of study on the performance characterization of the heaters themselves. In the current work, the performance of a conventional serpentine heater is characterized using ANSYS thermo-electric modeling software. The results show that conventional serpentine heaters are insufficient at providing uniform heat flux in applications where there is a lack of heat spreading-such as in the current embedded cooler — showing deviations ranging over 200 % of the nominal value. The deviations are caused by the many bends present in a serpentine pattern where current density concentrations vary significantly. Two alternate designs are proposed, and numerical simulations show that these new heater designs are capable of providing uniform heat flux, not deviating more than 20% from the nominal heat flux value. The conventional and newly proposed heaters are fabricated, tested, and analyzed with a working FEEDS system.

NASA’s Dragonfly mission is a rotorcraft lander which will explore several geologic locations on Saturn’s moon, Titan and investigate evidence of surface-level prebiotic chemistry as well as search for chemical signatures of water-based and/or hydrocarbon-based life. To perform molecular composition investigations in-situ, the payload includes the Dragonfly Mass Spectrometer (DraMS), being developed at NASA’s Goddard Space Flight Center (GSFC). DraMS will utilize laser desorption mass spectrometry (LDMS) to interrogate surface samples and measure the organic composition. Enabling this science capability is the Throttled Hydrocarbon Analysis by Nanosecond Optical Source (THANOS) laser being developed at NASA-GSFC. The THANOS laser is comprised of a solid state, passively Q-Switched Nd:YAG oscillator which is frequency converted to 266 nm and utilizes a RTP high voltage electro-optic for pulse energy control. The laser outputs <2.0 ns pulses with a maximum energy of approximately 200 uJ which can be emitted in 1 - 50 shot bursts at 100 Hz while performing LDMS science operations. The laser has the capability to throttle its UV pulse energy output from full attenuation to maximum energy to provide varying levels of fluence on samples in the DraMS instrument. We report on the THANOS’ laser technology development and space qualification effort including vibration, thermal vacuum cycling, radiation as well as optical damage testing due to Titan’s atmospheric composition, performed at NASA-GSFC from 2019 through 2022.

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