Microfabricated Bulk Piezoelectric Transformers

Piezoelectric voltage transformers (PTs) can be used to transform an input voltage into a different, required output voltage needed in electronic and electro- mechanical systems, among other varied uses. On the macro scale, they have been commercialized in electronics powering consumer laptop liquid crystal displays, and compete with an older, more prevalent technology, inductive electromagnetic volt- age transformers (EMTs). The present work investigates PTs on smaller size scales that are currently in the academic research sphere, with an eye towards applications including micro-robotics and other small-scale electronic and electromechanical sys- tems. PTs and EMTs are compared on the basis of power and energy density, with PTs trending towards higher values of power and energy density, comparatively, indicating their suitability for small-scale systems. Among PT topologies, bulk disc-type PTs, operating in their fundamental radial extension mode, and free-free beam PTs, operating in their fundamental length extensional mode, are good can- didates for microfabrication and are considered here. Analytical modeling based on the Extended Hamilton Method is used to predict device performance and integrate mechanical tethering as a boundary condition. This model differs from previous PT models in that the electric enthalpy is used to derive constituent equations of motion with Hamilton’s Method, and therefore this approach is also more generally applica- ble to other piezoelectric systems outside of the present work. Prototype devices are microfabricated using a two mask process consisting of traditional photolithography combined with micropowder blasting, and are tested with various output electri- cal loads. 4mm diameter tethered disc PTs on the order of .002cm 3 , two orders smaller than the bulk PT literature, had the followingperformance: a prototype with electrode area ratio (input area / output area) = 1 had peak gain of 2.3 (± 0.1), efficiency of 33 (± 0.1)% and output power density of 51.3 (± 4.0)W cm -3 (for output power of80 (± 6)mW) at 1M? load, for an input voltage range of 3V-6V (± one standard deviation). The gain results are similar to those of several much larger bulk devices in the literature, but the efficiencies of the present devices are lower. Rectangular topology, free-free beam devices were also microfabricated across 3 or- ders of scale by volume, with the smallest device on the order of .00002cm 3 . These devices exhibited higher quality factorsand efficiencies, in some cases, compared to circular devices, but lower peak gain (by roughly 1/2 ). Limitations of the microfab- rication process are determined, and future work is proposed. Overall, the devices fabricated in the present work show promise for integration into small-scale engi- neered systems, but improvements can be made in efficiency, and potentially voltage gain, depending on the applicatio

Catalyst-free, scalable heterocyclic flow photocyclopropanation

Industrial process development is driven by several factors, including safety, cost, robustness and environmental aspects. However, attempts to establish aryl diazo esters - which are highly valued in academic research for their reactivity as carbene precursors - in the chemical industry have been limited by their explosivity and toxicity. Their catalyst-free photolysis in continuous flow improves safety, sustainability and scalability compared to batch reactions. Herein, we report the continuous flow catalyst-free photocyclopropanation of heterocycles in up to grams per h productivity in a non-chlorinated, biodegradable solvent. Highly-functionalized cyclopropanated products are key intermediates in the synthesis of drugs and pharmaceutically-relevant compounds. Optimal conditions and process understanding were obtained by a Design of Experiments approach. In comparison with a large scale batch experiment, continuous flow conditions improved yield, productivity and process safety

Caldesmon ablation in mice causes umbilical herniation and alters contractility of fetal urinary bladder smooth muscle

The actin-, myosin-, and calmodulin-binding protein caldesmon (CaD) is expressed in two splice isoforms: h-CaD, which is an integral part of the actomyosin domain of smooth muscle cells, and l-CaD, which is widely expressed and is involved in many cellular functions. Despite extensive research for many years, CaD's in vivo function has remained elusive. To explore the role of CaD in smooth muscle contraction in vivo, we generated a mutant allele that ablates both isoforms. Heterozygous animals were viable and had a normal life span, but homozygous mutants died perinatally, likely because of a persistent umbilical hernia. The herniation was associated with hypoplastic and dysmorphic abdominal wall muscles. We assessed mechanical parameters in isometrically mounted longitudinal strips of E18.5 urinary bladders and in ring preparations from abdominal aorta using wire myography. Ca2+ sensitivity was higher and relaxation rate was slower in Calc1(-/-) compared with Cold1(+/+) skinned bladder strips. However, we observed no change in the content and phosphorylation of regulatory proteins of the contractile apparatus and myosin isoforms known to affect these contractile parameters. Intact fibers showed no difference in actin and myosin content, regardless of genotype, although KO-induced force tended to be lower in homozygous and higher in heterozygous mutants than in WTs. Conversely, in skinned fibers, myosin content and maximal force were significantly lower in Cold1(-/-) than in WTs. In KO abdominal aortas, resting and U46619 elicited force were lower than in WTs. Our results are consistent with the notion that CaD impacts smooth muscle function dually by (1) acting as a molecular brake on contraction and (2) maintaining the structural integrity of the contractile machinery. Most importantly, CaD is essential for resolution of the physiological umbilical hernia and ventral body wall closure

Li–Pd–Rh-D2O electrochemistry experiments at elevated voltage

In 2013, the U.S. Navy disclosed an electrochemistry procedure intended to produce MeV-energy nuclear particles, based on eV-energy electrical inputs, which may be indicative of a new scientific phenomenon. This work is based on the 2013 disclosure and shows initial evidence validating the prior claims of nuclear particle generation. Additionally, several variations on the 2013 electrochemical recipe are made in order to find a highly repeatable recipe for future replications by other teams. The experiments described here produced dense collections of tracks in solid-state nuclear track detectors, radio frequency (RF) emissions, and anomalous heat flux, which are indicative of potential nuclear, or unusual chemical, reactions. Experimental results include tracks in solid-state nuclear track detectors similar in size to tracks produced by 4.7 MeV alpha particles on identical detectors exposed to radioactive Th-230; RF pulses up to 6 dB above the noise floor, which indicate that these signals were likely not background noise and not caused by known chemical reactions; and heat flux of 10 s of kJ, measured to 6σ significance, over and above input electrical energy, indicative of unknown exothermic reactions. Six out of six nuclear track detectors, utilized in experiments and interrogated for tracks post-experiment, produced positive results that our team attributes to thousands of individual particle impacts in dense clusters, likely with energies between 0.1 and 20 MeV. Similar nuclear particle, thermal, and RF results have separately appeared in prior reports, but in this work, all three categories of anomalous behavior are reported. Results indicate that the 2013 procedure may be a useful guide toward a set of highly repeatable reference experiments, showing initial but not overwhelming evidence of a new scientific phenomenon. Repeatable recipes are shared so that other groups may replicate and extend the present work