Packaging Technologies for Millimeter Scale Microsystems in Harsh Environment Applications

Microsystems capable of sensing temperature, pressure and other parameters are needed for many applications, for example, gathering information in downhole environments for oil and gas exploration. Certain target locations limit the size of the microsystems to millimeter or even sub-millimeter scale. In addition, the high temperature, high pressure, and corrosive ambient environments are challenging for microsystems. Target environments include 125°C temperature, 50 MPa pressure, and salinity standards consistent with American Petroleum Institute (API) brine (8% NaCl + 2% CaCl2). Other chemicals including hydrocarbons and cement slurry are also found in these environments. The system package plays a critical role as it protects the system components against environment, while also providing the physical coupling to the environment, e.g., for communication modules and pressure sensors. The package must be made of mechanically and chemically robust materials. High temperature assembly steps must be avoided in the packaging process (such as bonding above 200°C), because these steps are generally incompatible with embedded batteries and polymer-based sensors. The development of system package and relevant technologies is the focus of this dissertation. This dissertation first describes the design and fabrication of sapphire-on-steel packages in two sizes (0.8 mm and 8 mm), which are capable of isolating high pressure while allowing optical communication. These packages have been operated with embedded electronics at 125ºC and ≈70 MPa in API brine, hydrocarbons, and cement slurry. Additionally, polymer-in-tube packages are reported, which allow the embedded pressure sensors to couple with the environment. These packages have been successfully operated with embedded electronics and sensors at 125ºC and 50 MPa in API brine. A third approach of encapsulation that is reported involves polymer film encapsulation, which has the potential to significantly improve the chemical resistance of microsystems. Finally a batch-mode packaging process is presented based on micro-crimping, enabling room temperature assembly for sub-millimeter scale packages made by metal alloys. This packaging process has been demonstrated by a 5×5 array of 0.5 mm packages. These packages have survived at least 200 MPa pressure and at least 72 h in API brine.PHDMechanical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/135761/1/yushuma_1.pd

Efficient display of active lipase LipB52 with a Pichia pastoris cell surface display system and comparison with the LipB52 displayed on Saccharomyces cerevisiae cell surface

<p>Abstract</p> <p>Background</p> <p>For industrial bioconversion processes, the utilization of surface-displayed lipase in the form of whole-cell biocatalysts is more advantageous, because the enzymes are displayed on the cell surface spontaneously, regarded as immobilized enzymes.</p> <p>Results</p> <p>Two <it>Pichia pastoris </it>cell surface display vectors based on the flocculation functional domain of FLO with its own secretion signal sequence or the α-factor secretion signal sequence were constructed respectively. The lipase gene <it>lipB52 </it>fused with the <it>FLO </it>gene was successfully transformed into <it>Pichia pastoris </it>KM71. The lipase LipB52 was expressed under the control of the <it>AOX1 </it>promoter and displayed on <it>Pichia pastoris </it>KM71 cell surface with the two <it>Pichia pastoris </it>cell surface display vectors. Localization of the displayed LipB52 on the cell surface was confirmed by the confocal laser scanning microscopy (CLSM). The LipB52 displayed on the <it>Pichia pastoris </it>cell surface exhibited activity toward <it>p</it>-nitrophenol ester with carbon chain length ranging from C₁₀to C₁₈, and the optimum substrate was <it>p</it>-nitrophenol-caprate (C₁₀), which was consistent with it displayed on the <it>Saccharomyces cerevisiae </it>EBY100 cell surface. The hydrolysis activity of lipase LipB52 displayed on <it>Pichia pastoris </it>KM71-pLHJ047 and KM71-pLHJ048 cell surface reached 94 and 91 U/g dry cell, respectively. The optimum temperature of the displayed lipases was 40°C at pH8.0, they retained over 90% activity after incubation at 60°C for 2 hours at pH 7.0, and still retained 85% activity after incubation for 3 hours.</p> <p>Conclusion</p> <p>The LipB52 displayed on the <it>Pichia pastoris </it>cell surface exhibited better stability than the lipase LipB52 displayed on <it>Saccharomyces cerevisiae </it>cell surface. The displayed lipases exhibited similar transesterification activity. But the <it>Pichia pastoris </it>dry cell weight per liter (DCW/L) ferment culture was about 5 times than <it>Saccharomyces cerevisiae</it>, the lipase displayed on <it>Pichia pastoris </it>are more suitable for whole-cell biocatalysts than that displayed on <it>Saccharomyces cerevisiae </it>cell surface.</p

Advanced Nanoparticle Coatings for Stabilizing Layered Ni‐Rich Oxide Cathodes in Solid‐State Batteries

Improving the interfacial stability between cathode active material (CAM) and solid electrolyte (SE) is a vital step toward the development of high-performance solid-state batteries (SSBs). One of the challenges plaguing this field is an economical and scalable approach to fabricate high-quality protective coatings on the CAM particles. A new wet-coating strategy based on preformed nanoparticles is presented herein. Nonagglomerated nanoparticles of the coating material (≤5 nm, exemplified for ZrO$_{2}$) are prepared by solvothermal synthesis, and after surface functionalization, applied to a layered Ni-rich oxide CAM, LiNi$_{0.85}$Co$_{0.10}$Mn$_{0.05}$O$_{2}$ (NCM85), producing a uniform surface layer with a unique structure. Remarkably, when used in pelletized SSBs with argyrodite Li$_{6}$PS$_{5}$Cl as SE, the coated NCM85 is found to exhibit superior lithium-storage properties (q$_{dis}$ ≈ 204 mAh g$_{NCM85}$$^{-1}$ at 0.1 C rate and 45 °C) and good rate capability. The key to the observed improvement lies in the homogeneity of coating, suppressing interfacial side reactions while simultaneously limiting gas evolution during operation. Moreover, this strategy is proven to have a similar effect in liquid electrolyte-based Li-ion batteries and can potentially be used for the application of other, even more favorable, nanoparticle coatings

A Quasi‐Multinary Composite Coating on a Nickel‐Rich NCM Cathode Material for All‐Solid‐State Batteries

Inorganic solid-state batteries are attracting significant interest as a contender to conventional liquid electrolyte-based lithium-ion batteries but still suffer from several limitations. The search for advanced coatings for protecting cathode materials in solid-state batteries to achieve interfacial stability is a continuing challenge. In the present work, the surface of an industrially relevant Ni-rich LiNi$_x$Co$_y$Mn$_z$O$_2$ cathode material, NCM-851005 (85 % Ni), was modified by applying a coating containing Li, Nb and Zn, aiming at a composition Li$_6$ZnNb$_4$O$_14$, by means of sol-gel chemistry. Detailed characterization using scanning transmission electron microscopy combined with energy-dispersive X-ray spectroscopy and nano-beam electron diffraction showed that the surface layer after heating in O$_2$ at 500 °C contains Li$_3$NbO$_4$ nanocrystals and Li$_2$CO$_3$, with Zn presumably acting as a dopant. The protective coating on the NCM-851005 secondary particles significantly increased the cycling performance (reversible capacity, rate capability etc.) and stability of full cells using argyrodite Li$_6$PS$_5$Cl as solid electrolyte. Interestingly, the level of improvement is superior to that achieved with conventional LiNbO$_3$ coatings

Spatiotemporal patterns and spatial risk factors for visceral leishmaniasis from 2007 to 2017 in Western and Central China: a modelling analysis

Visceral leishmaniasis (VL) is a neglected disease caused by trypanosomatid protozoa in the genus Leishmania, which is transmitted by phlebotomine sandflies. Although this vector-borne disease has been eliminated in several regions of China during the last century, the reported human VL cases have rebounded in Western and Central China in recent decades. However, understanding of the spatial epidemiology of the disease remains vague, as the spatial risk factors driving the spatial heterogeneity of VL. In this study, we analyzed the spatiotemporal patterns of annual human VL cases in Western and Central China from 2007 to 2017. Based on the related spatial maps, the boosted regression tree (BRT) model was adopted to explore the relationships between VL and spatial correlates as well as predicting both the existing and potential infection risk zones of VL in Western and Central China. The mined links reveal that elevation, minimum temperature, relative humidity, and annual accumulated precipitation make great contributions to the spatial heterogeneity of VL. The maps show that Xinjiang Uygur Autonomous Region, Gansu, western Inner Mongolia Autonomous Region, and Sichuan are predicted to fall in the highest infection risk zones of VL. Approximately 61.60 million resident populations lived in the high-risk regions of VL in Western and Central China. Our results provide a better understanding of how spatial risk factors driving VL spread as well as identifying the potential endemic risk region of VL, thereby enhancing the biosurveillance capacity of public health authorities

Resolving the Role of Configurational Entropy in Improving Cycling Performance of Multicomponent Hexacyanoferrate Cathodes for Sodium‐Ion Batteries

Mn-based hexacyanoferrate (Mn-HCF) cathodes for Na-ion batteries usually suffer from poor reversibility and capacity decay resulting from unfavorable phase transitions and structural degradation during cycling. To address this issue, the high-entropy concept is here applied to Mn-HCF materials, significantly improving the sodium storage capabilities of this system via a solid-solution mechanism with minor crystallographic changes upon de-/sodiation. Complementary structural, electrochemical, and computational characterization methods are used to compare the behavior of high-, medium-, and low-entropy multicomponent Mn-HCFs resolving, to our knowledge for the first time, the link between configurational entropy/compositional disorder (entropy-mediated suppression of phase transitions, etc.) and cycling performance/stability in this promising class of next-generation cathode materials

Predictors of lung adenocarcinoma with leptomeningeal metastases: A 2022 targeted-therapy-assisted molGPA model

Objective: To explore prognostic indicators of lung adenocarcinoma with leptomeningeal metastases (LM) and provide an updated graded prognostic assessment model integrated with molecular alterations (molGPA). Methods: A cohort of 162 patients was enrolled from 202 patients with lung adenocarcinoma and LM. By randomly splitting data into the training (80%) and validation (20%) sets, the Cox regression and random survival forest methods were used on the training set to identify statistically significant variables and construct a prognostic model. The C-index of the model was calculated and compared with that of previous molGPA models. Results: The Cox regression and random forest models both identified four variables, which included KPS, LANO neurological assessment, TKI therapy line, and controlled primary tumor, as statistically significant predictors. A novel targeted-therapy-assisted molGPA model (2022) using the above four prognostic factors was developed to predict LM of lung adenocarcinoma. The C-indices of this prognostic model in the training and validation sets were higher than those of the lung-molGPA (2017) and molGPA (2019) models. Conclusions: The 2022 molGPA model, a substantial update of previous molGPA models with better prediction performance, may be useful in clinical decision making and stratification of future clinical trials