bluuebunny/crossref_metadata_2025 huggingface dataset:
Thermal Transpiration As a Co-Located Micro-Scale Source of High Pressure Gas for MEMS Devices
Authors: Young M. , Shiflett G. , Muntz E. P. , Vargo S.
Published: November 2021

Applications of the Knudsen Compressor, a thermal transpiration pump, as a co-located source of high-pressure gas (greater than 1 atm.) for MEMS valves, actuators, and fluid flow devices has been investigated. Relying only on existing materials and technologies, it is shown that it should be possible to construct MEMS Knudsen Compressors to provide compressed gas up to pressures of about 10 atm while making use of ambient gases as the working medium. The theoretical performance of Knudsen Compressors operating from 1 atm up to 10 atm is evaluated with a previously developed rarefied gas dynamic, transitional flow model for Knudsen Compressor cascades. In one design a 27 stage Knudsen Compressor provides a pressure increase from 1 atm to 10 atm at a flow rate of 2 × 10−3 atm-cm3/s. The compressor occupies a volume of 40 mm3 and has a power requirement of 0.25W. An apparent high-pressure limit for Knudsen Compressors, roughly 100 atm, is discussed. The pressure range between 10 atm. and 100 atm. requires nanometer and smaller size capillaries in the transpiration membrane. Several physical effects that become important at these small dimensions are identified and discussed along with their qualitative influence on the performance of the Knudsen Compressor. It is concluded that existing materials with sub-nanometer capillaries have thermal conductivities that are too high, leading to inappropriate power consumption for a MEMS device; for now, the practical upper limit on the pressure to which a MEMS Knudsen Compressor can operate is around 10 atm.
A Pressure-Controlled Torsion-Type Check Microvalve
Authors: Hong Chien-Chong , Lee Sang-Mae , Ahn Chong H. , Nielsen Matthew , McManus Keith
Published: November 2021

In this work, a pressure controlled torsion-type check microvalve has been simulated, designed, fabricated and successfully characterized for a high pressure control. Structural and fluidic analysis for a check microvalve has been performed and compared with experimental results of the fabricated device. A nickel structure fabricated using UV-LIGA techniques has been adopted as a pressure-controlled torsion bar. The results obtained from simulations and measurements show an excellent accordance at low pressure. The device realized in this work has a high potential as a high pressure passive valve for small scale propulsion system.
MEMS, MOEMS and Optoelectronics
Authors: Gilleo Ken
Published: November 2021

Traditional MEMS (Micro-Electro-Mechanical Systems) devices have been with us for decades. A micromechanical motion sensor connected to the airbag electronics in your vehicle is always ready to send the instant message that can save your life. Sensing an abrupt change in motion indicating a crash, the MEMS accelerometer sends the command to fire the airbag. Today, multiple-axis motion-monitoring chips are on the market, so sensitive, that they can measure subtle hand motions. The ADI 202 will be demonstrated as part of this presentation. MEMS sensors are in wide use today but much more advanced activator type products are gaining market recognition as this technology advances.

MOEMS (MicroOptoElectroMechanical Systems), or optical MEMS, adds “light” or optics to the technology cluster to provide the most advanced nano-devices yet. Texas Instruments is a pioneer in the MOEMS field with their highly successful Digital Micromirror Device (DMD™) now used in the best digital projectors and in cinemas. The DMD has more moving parts than a Boeing 777 and the Space Shuttle combined. We will do a case study of the DMD technology and review three products including “Redtooth” fiberless optics wireless.

Optoelectronics, an “old-new” technology, is now the centerpiece of advanced communications especially for long-haul communications. A single optical fiber replaces over 4-million copper wires because of the unimaginable bandwidth resulting from the million-times higher frequency of light and the ability to multiplex hundreds of signals over a single fiber using Wave Division Multiplexing (WDM). But Internet links must be switched back and forth between electronic and photonic media. The reason is that routers and switches depend on electronics while transmission utilizes photonics. Many believe that MOEMS-based switches will solve the multiple conversion bottleneck allowing all-optical systems to smoothly handle traffic. So while MEMS, MOEMS and OE are separate, they all come together in fields like telecom. This paper will highlight these technologies and show how they will merge in an incredible future.
Low Temperature Eutectic Bonding for In-Plane Type Micro Thermoelectric Cooler
Authors: Yao Da-Jeng , Chen Gang , Kim Chang-Jin “CJ”
Published: November 2021

We report the fabrication of a micro thermoelectric (TE) cooler (μ-TEC), lithographically patterned and integrated with silicon micromachining technologies, with an emphasis on two low temperature eutectic bonding techniques used to connect p- and n-type TE microbeams. The result is a microscale cooling spot suspended only by microbridges made purely of TE material at the center of a silicon frame. With no additional material in contact with the cooling spot, thermal leakage is minimized — the critical requirement in making effective μ-TEC’s. Since TE materials degrade at high temperature (> 400°C), connections of p-n microbeams are limited to only low temperature (∼250°C) bonding methods. The overall fabrication procedure has been designed such that most TE thin films can be used without the need to redesign the remaining process flow of the device as TE materials research continues to advance.
Laser Micromachining of MEMS Packaging Materials
Authors: Kancharla Vijay V. , Hendricks Kira K. , Chen Shaochen
Published: November 2021

Tools for microfabrication on planar silicon substrates have led to remarkable advances in miniaturization of MEMS silicon devices. Silicon however has a limited functionality in many MEMS applications. Applications in which there are requirements for electrically or thermally insulating substrates, low capacitance, resistance to corrosion, or hermetic sealing limit some capabilities of silicon as a MEMS material. The introduction of packaging materials such as ceramics, polymers, and glass in MEMS fabrication makes it easy to fabricate 3-D meso or large-scale devices for a wide range of applications at cheaper cost. The application of these materials helps in constructing complex multilayer MEMS structures, which is one of the limitations of traditional Silicon MEMS devices. In this work we investigate and report laser micromachining of MEMS packaging materials such as ceramics and polymers for non-silicon MEMS device fabrication. A review of and general discussion is also presented in regard to the role of lasers in fabricating non-silicon MEMS devices. The experimental results of microstucturing these materials, SEM micrographs, surface morphology after machining, and their applications are reported.
Micromachined Flexible Interconnect for Wafer Level Packaging
Authors: Joung Yeun-Ho , Allen Mark G.
Published: November 2021

Wafer Level Packaging (WLP) of microelectronic circuitry, in which critical package elements are formed on the silicon wafer prior to dicing, has several advantages over conventional packaging techniques, such as one-step testability of multiple chips on a silicon wafer prior to dicing, and the possibility of high input-output (I/O) density. One of the critical elements of WLP is the interconnect. Freely movable interconnects, which act like springs when thermally and mechanically loaded, can be used to relieve thermal and bonding-generated stresses, potentially resulting in improved testablility and reliability in WLP. In this work, flexible free-standing and no-underfill inteconnects were fabricated in a CMOS-compatible surface micromachining technology directly on a silicon wafer. The compliance of these interconnects up to 50 microns in the direction normal to the wafer was measured. Deflections and thermal expansions under mechanical-thermal stress were also simulated using finite element methods. Good agreement was achieved between the measured compliance and that predicted by the finite element analysis.
New Approach to Development of Packaging for MEMS Inertial Sensors
Authors: Pryputniewicz Ryszard J. , Marinis Thomas F. , Hanson David S. , Furlong Cosme
Published: November 2021

Development of MEMS inertial sensor packages for high performance applications cannot be accomplished by analysis alone. There are too many unknown material properties, process conditions, and assembly tolerances to make this feasible. Extensive performance evaluation of packaged sensors is also prohibitively expensive and time consuming. However, recent advances in the ACES methodology of micro-interferometric measurements coupled with analytical and computational analysis offer a considerable promise for effective optimization of the design of advanced sensor packages. Sub-micron displacements of sensors can be readily measured with nanometer accuracy over a range of environmental conditions. This greatly facilitates the validation and refinement of quantitative models of packages and complex material structures. This paper describes the new approach, based on optoelectronic laser interferometric microscope methodology, to development of packaging for MEMS inertial sensors and discusses preliminary results that have been obtained.
A Device for Fabricating Protein Chips Using Surface Acoustic Wave Atomizer and Electrostatic Deposition
Authors: Kim Joonwan , Yamagata Yutaka , Inoue Kozo , Higuchi Toshiro
Published: November 2021

To fabricate protein chips from solution, we propose an advanced system by utilizing the surface acoustic wave atomizer and electrostatic deposition. The system mainly consists of three components: the protein solution supply system, the piezo-SAW atomizer, and the electrostatic particle collector. Protein chips are successfully formed by the device and the particle diameter ranged from 0.2 to 1μm using BSA. The chip of luciferase from firefly was formed by the device and was dissolved in reaction mixture to show strong luminescence. Chips of Anti-mouse IgG was also formed and cross-linked and their activity as immuno globulin was verified by fluorescence method. By utilizing insulation mask, protein chips with desired shapes like rectangular or circular are formed with relatively uniform thickness. Though there are rooms for improvements in terms of deposition efficiency, the device proved to be very effective in forming biochemical active protein chips.
A Capillary Electrophoresis Platform With “On-Chip” Electrochemical Detection: Experimental and Computational Flow Studies
Authors: Roussel Thomas J. , Keynton Robert S. , Walsh Kevin M. , Crain Mark M. , Naber John F. , Jackson Douglas J. , Baldwin Richard P.
Published: November 2021

The purpose of this study was to compare experimental electrokinetic plug flow velocities to computational flow models of microfabricated capillaries. Electroosmotic flow studies of dichlorofluorescein and electrophoretic separation of dopamine and catechol in a microfabricated capillary electrophoresis (CE) system were performed both experimentally and computationally. A “balanced cross design” consisting of a bent 2 cm long injection channel and a straight 2 cm long separation channel was used. The geometry of the capillary was 65 μm wide and 20 μm deep. For the fluorescein study, separation voltages ranging between 0.25 kV and 1 kV were applied, while voltages ranging from 100 V to 550 V were used in the separation studies. Laser Induced Fluorescent (LIF) images were obtained for flow visualization and qualitative analysis in the electroosmotic flow studies, while electrochemical potentials were acquired using “on-chip” electrodes interfaced to a custom-designed power supply and electrochemical detection (ECD) circuit. Finite element models of the experimental device were generated and flows were simulated using commercially available software. For the electroosmotic flow studies, the computational results were found to be within ± 11% of the experimentally obtained values. Similarly, the results of the computational separations of catechol and dopamine predicted plug velocities that were within ± 7.6% of the experimentally determined values.
Constrained Layer Damping Treatments for Microstructures
Authors: Hsu Yi-Chu , Shen I. Y.
Published: November 2021

This paper presents a bulk micro-machining process to fabricate micro-constrained layer treatments (MCLT) on a microstructure to increase its damping. MCLT consists of a silicon base beam or plate, a viscoelastic photoresist layer, and an aluminum constraining layer. Silicon base beams and plates are fabricated from {100} wafer through EDP etch and BOE etch. A 4.5-μm thick photoresist AZ4620 is deposited on the silicon base beam as the viscoelastic layer. Finally, an aluminum layer is deposited through LPVD as the constraining layer. To evaluate damping performance of MCLT, silicon beams with and without MCLT are subjected to swept-sine excitations by PZT from 0 to 100 kHz. In addition, laser Doppler vibrometer and spectrum analyzer were used to measure frequency response functions (FRF) of the specimen. A finite element analysis identifies the resonance modes measured in FRF. Experimental results confirm that MCLT can increase damping of silicon beams by at least 40%. Significantly larger damping improvement is expected, when the fabrication process is refined.
Process Modeling of Projection Micro Stereo Lithography for Three-Dimensional MEMS
Authors: Sun Cheng , Fang Nicholas , Zhang Xiang
Published: November 2021

We present in this paper a high-resolution projection micro stereo lithography (PμSL) process by using a spatial light modulator as the dynamic mask. This unique technology provides a parallel fabrication of highly complex 3D microstructures for MEMS. Based on the understanding of underlying mechanism, the process model has been developed and verified by experiment. The UV doping effect has been examined as it can effectively reduce the curing depth without compromising the chemical property of the resin. Finally, the fabrication of complex 3D microstructures, such as matrix, micro-spring array, with the smallest feature of 10 μm has been reported.
High Temperature Supersonic Jet Facility for Aeroacoustic Studies
Authors: Greska Brenton J. , Krothapalli Anjaneyulu
Published: November 2021

This paper describes a newly built experimental facility at the Florida State University to develop innovative technologies for the noise suppression and mixing control of high-speed jets. This facility is capable of generating jet flows up to a maximum jet exit Mach number of about 2.5 at stagnation temperatures reaching up to 1500K. The facility can accommodate nozzles having an exit diameter of about 80 mm. At the maximum operating conditions, the jet can be run continuously for about 15 minutes. The jet exhausts into an anechoic room that measures 5.2 m (width) × 5.8 m (length) × 4 m (height). A sudden expansion (SUE) burner using Ethylene as its fuel is used to heat the high-pressure air. The instrumentation includes: High Resolution Infrared camera, stereoscopic Particle Image Velocimetry and Laser Speckle Displacement method for flow field measurements, high temperature unsteady pressure probes for the measurement of pressure fluctuations in the hydrodynamic field, and microphones with high speed data acquisition for far-field narrow band sound measurements.
ARL/PENN State Pump Test Loop
Authors: Hambric Stephen A. , Yocum Adam M. , Cawley Thomas , Willits Steven M.
Published: November 2021

A new pump test facility has been designed and built at the Applied Research Laboratory at Penn State University (ARL/PSU). The loop, which complements the many other hydroacoustic measurement facilities at ARL/PSU, can accommodate a wide range of inflow piping, operating conditions, and pump configurations and has been constructed of high quality components to ensure its longevity as a world-class test facility. Measurements of pump hydrodynamic and hydroacoustic performance, as well as measurements of the characteristics of the turbulent flow entering pumps and other devices may be made in the facility. Measurements of the hydroacoustic character of passive devices, such as control valves, are also possible in the loop. The pump loop has been designed to minimize background noise contamination of vibration and fluid acoustic pressure measurements. Loop background noise levels measured with various sources in the building operating (compressors, motors, and other machinery) are extremely low and show that the noise control measures are effective. Wide optical access for Laser Doppler Velocimetry (LDV) measurements allows for measuring space-time correlations of pipe flow turbulence. Sample measurements of turbulence spectra and space-time correlations downstream of a 90 degree elbow are shown, and are of excellent quality.
Experimental Investigations of an Electro-Dynamically Driven Thermoacoustic Cooler
Authors: Mongeau Luc , Alexander Aaron , Minner Brian , Paek In-Su , Braun James E.
Published: November 2021

Experimental investigations of an electro-dynamically thermoacoustic cooler prototype were performed. The prototype was designed to provide 140 W of cooling across a 22 °C temperature lift. Operation using a 55% helium-argon mixture at a mean pressure of 20 bar and a frequency near 180 Hz was targeted. The prototype used a tuned “moving magnet” electro-mechanical actuator. Initial investigations aimed at characterizing the electro-mechanical behavior and performance of the driver. The acoustic response of the system with no cooling elements was then investigated to validate the experimental procedures. The thermal performance of the complete system was then measured over a range of operating conditions, for varying gas mixtures. Detailed sound pressure and temperature measurements provided information from which the overall efficiency, capacity, and temperature lift of the cooling system were estimated, in addition to the heat exchange coefficients and performance of the heat exchangers. Net acoustic power inputs of up to 120 W were achieved with an electro-acoustic transduction efficiency varying between 20% and 50%, reaching values as high as 60% in a few cases. In comparison, the theoretical maximum driver efficiency was 65%. The measured cooling capacity varied greatly and peaked near 130 W for a temperature lift of 12°C. The acoustic pressure amplitudes were near 3% of the mean pressure in the stack region, and the heat rejected to a secondary fluid reached 250 W. The best relative coefficient of performance achieved was less than 3% of Carnot, based on the net input acoustic power. The best overall efficiency achieved was thus 1.2% of Carnot. While the acoustic power level exceeded the target value for the desired cooling load, the cooling power was well below the expected value, and the target temperature lifts and efficiencies were not achieved. This was generally attributed to “nuisance” heat loads, acoustic streaming effects, and migration of species within the inhomogeneous mixture. The non-dimensional heat exchanger performance in the thermoacoustic system was found to be slightly less than that in a steady uniform flow when the root-mean-square particle velocity is used for a velocity scale, and the stack end temperature is used in the calculation of the temperature lift. It was also found that this performance value is significantly better than that predicted by linearized boundary layer models often used in linear acoustic models.
Optimum Stiffener Design to Reduce Broadband Vibration and Sound Radiation
Authors: Lee Dongjai , Belegundu Ashok D. , Koopmann Gary H.
Published: November 2021

This paper presents a rib-stiffener pattern design method for reducing vibration energy and/or radiated acoustic power from a vibrating structure. Structural dynamics, acoustics and optimization are programmed in a unified code. To avoid difficulties in defining proper design variables such as the location, the number and the size of stiffeners to be attached on a structure, this paper adopts the idea of “topology optimization”, based on finite elements. This approach enables one to find an optimal rib-stiffener pattern by using a simple design variable, e.g., the density of finite elements. To illustrate this method, a rectangular plate with clamped edges is optimized to reduce the radiated sound power/kinetic energy and the results are compared to that the same plate but without rib-stiffeners.
A New Numerical Technique for the Unification of Propagation and Scattering Problems in Underwater Acoustics
Authors: Sidorovskaia Natalia A.
Published: November 2021

A new numerical algorithm for obtaining a normal mode solution of the Helmholtz equation for an arbitrary sound speed profile in the ocean is discussed. The new method represents the solution as a series expansion in terms of basis modal functions corresponding to the solution of a reference iso-velocity problem. The numerical optimization procedures that allow improving the computational performance of the code are considered. An important advantage of the presented algorithm is a straightforward transformation of the solution into spherical representation suitable for mapping an incident waveguide field into a scattered one to describe a scattering process from an elastic object in a waveguide. The mathematical formulation of the transformation is presented. The numerical model has already proved to be competitive with Navy standard propagation simulation tools.
Computation of Noise From Fully-Expanded Supersonic Jet Using Low-Dispersion Methodology
Authors: Baysal Oktay , Idres Moumen M.
Published: November 2021

A novel mathematical model and its solution are presented to simulate the generation and the propagation of supersonic jet noise. An objective in developing this model was to seek an approach that would be feasible in a design environment, where a number of consecutive simulations would be needed. Hence, a judicious compromise was afforded between the computational efficiency and the overall accuracy of the methodology in representing the underlying physics. The noise generation was modeled as axisymmetric or helical instabilities introduced in the upstream boundary. The propagation was simulated by solving the three-dimensional and linearized Euler equations in a very efficient way by a dispersion-relation-preserving scheme. The predicted relative values of the sound pressure level contours have successfully been compared with the experimental data and other computational approaches.
Reconstruction of Transient Acoustic Radiation From Impulsively Accelerated Objects
Authors: Bajwa Manjit S. , Wu Sean F.
Published: November 2021

The HELS method (Wu, 2000) is extended to reconstruction of transient acoustic radiation from an impulsively accelerated object. The temporal acoustic pressure field is reconstructed by taking an inverse Fourier transformation of the acoustic pressure in the frequency domain. The infinite integral is replaced by a contour integral and evaluated using the residue theory. The formulations thus derived are valid for a spherical surface with an arbitrary normal velocity distribution. These formulations are used to reconstruct the normal surface velocities and transient acoustic fields generated by explosively expanding sphere, impulsively accelerating sphere, and impulsively accelerating baffled sphere. Results show that satisfactory reconstruction can be obtained with relatively few measurements taken around the object under consideration.
Active Acoustic Control of Conical Bores Through Actuating Boundary Conditions
Authors: Farinholt Kevin M. , Leo Donald J.
Published: November 2021

This paper presents an investigation into control of sealed conical bores. Beginning with an impedance model of the enclosure, frequency domain and state-space models of the system are developed as functions of the geometric and mechanical properties of the cone. A discussion of coupling this acoustic model with the electrical and mechanical dynamics of a permanent magnet speaker are also presented. Using a sample geometry, the accuracy of this coupled model is validated against experimental results, indicating accuracy levels of 1.75% or lower in prediction of resonance frequencies. This paper concludes with a study on applying Linear Quadratic Regulator techniques to this system, relating trade-offs between average pressure and control voltages. The results of our simulations indicate that pressure reductions of 40.5% are attainable with average control voltages of 3.26 volts when subject to low level impulse disturbances, as applied to an example geometry.
Principles for Procedure System Management
Authors: Sturdivant Maggie , Carnes Earl
Published: November 2021

This paper provides a preview of a DOE Technical Standard “Principles for Procedure System Management” due to be released in the fall of 2001. Procedures are identified as causal factors in accidents, operating events, and lessons learned within the U.S. Department of Energy (DOE), the commercial nuclear industry, and other complex industries. While literature exists regarding the control, production, and use of procedures, DOE has not provided guidance on the collective elements and attributes of an effective procedure system. This paper describes a set of design control features that can systematically improve development and maintenance of procedures.
Case Study: The Safety of Wood Railings
Authors: Barnett Ralph L. , Switalski William G.
Published: November 2021

When the handrail assembly broke away from a wooden deck attached to the rear of a private residence, the victim fell 12 feet to the lawn and sustained injuries rendering him a quadriplegic. Although the local building code required the handrail to withstand a 200 lb load applied in any direction at any point on the handrail, no guidance was given to the do-it-yourselfer who built the deck and railings to assure him that the final construction would produce an acceptable railing. The authors conducted testing and a statistical analysis of railing strength comparing the construction method used by the builder of the accident railing to another construction method utilizing a commercially available handrail bracket. The test program demonstrates that the strength of the wood used to build handrails can vary greatly and that a controlled method of building a handrail is necessary to ensure the integrity of a product intended to be consumer customized and assembled. It is necessary to have acceptable methods of railing construction because the failure of a railing joint can be life threatening. This is especially true in the consumer/do-it-yourself market where the designer/builder is not necessarily knowledgeable about building codes or construction methods. A commercially available handrail bracket known as Create-A-Rail® can provide the consumer with the guidance necessary to assure an acceptable handrail / post joint.
Outline of the E&TM Group Symposium “Partnering to Succeed: Keys to Managing Technology Development, Risk and Globalization”
Authors: Honda Hiroshi
Published: November 2021

The current paper introduces an outline of the subject symposium with “twenty-six sessions,” shown in Table 1, for ASME 2001 IMECE.(1)
Virtual Teams: Communicating in a Global Business
Authors: Schlueter Carolyn A. , Lloyd John R. , Hinds Timothy J. , Goodman Erik D.
Published: November 2021

Globally distributed engineering design teams face many additional challenges to their success over traditional teams where the team members are co-located. Not only are these international teams burdened with the tasks of proper team formation and selection of effective communication tools, but they must also overcome the barriers of distance, time, language, and culture. Virtual teams can be effective when proper communication tools are implemented and team management issues are understood. The practice of engineering has become an international practice, and the concept of team work has taken on a new level of interaction. In the near future, virtual teams will evolve from being a competitive business edge to common practice. Key issues are discussed in this paper.
Basic Needs of Human Beings As the Purposes and Foundations for the Existence of Governing Institutions and the Advancement of Science and Technology
Authors: Wong Po Kee
Published: November 2021

This paper summarizes the most recent advancement of space technologies and its impacts to our social-economic management systems based on the needs of energies by all human beings for survival. The paper contains two subsections as a part for the solution of the educational and social-economic problems. The one with education is entitled “EVIDENCES OF IMPACTS AND RESISTANCES TO IMPLEMENT A CONTROVERSIAL, SCIENTIFIC PROBLEM IN CURRICULUM DEVELOPMENT” and the other is entitled “FORMULATION OF THE PHYSICAL ECONOMIC THEORY AND ITS APPLICATION IN COST AND PRICE ANALYSIS FOR CONTRACT ADMINISTRATION ORGANIZATIONS”.
Paradigm Shift: A Move Toward Renewable Energies
Authors: Krimmel Jeffrey J. , Sokol Jacqueline A.
Published: November 2021

With the recent realization that the United States will be unable to meet regulations set forth at the Kyoto Climate Conference and the excessive burden the energy shortage in California has placed on the southwestern portion of United States, U.S. companies are beginning to look for alternative means of energy production. Broad-based carbon taxes are among the most promising and important of the new tools for achieving reductions in greenhouse gas emissions and promoting the use of alternative energy resources. Many private sector entities are shifting vast amounts of resources to the research and development of alternative means of energy production, but these efforts are futile without a far-reaching governmental initiative to reach the same ends. With other global powers, including Japan and many European nations, producing inquiries into the benefits attained through greenhouse gas taxation, the United States is in a pivotal position to take the lead in efforts toward global sustainable development.

A carbon tax, phased in gradually sector-by-sector or implemented in an immediate fashion, would promote more environmentally friendly means of energy production while not hampering the competitiveness of one of the nation’s most important industries. This initiative would send a clear signal to all levels of corporate management that energy production and consumption issues must be addressed in order to continue thriving in a greener U.S. economy. The boom in alternative energy resources will trigger an increase in the development of new technologies and research opportunities, which would require more highly trained mechanical engineers in the workforce.

This paper will briefly discuss several carbon tax alternatives. Such a tax would allow the United States to realize three significant advantages not offered by today’s antiquated means of energy production: (1) generating a larger amount of total revenue from a smaller total tax burden, (2) evenly affecting the competitiveness of the residential, industrial, and commercial economic sectors so as not to punish any one disproportionately, and (3) promoting enhanced environmental quality through the increased research and use of renewable and other alternative energies. Mechanical engineers have an extremely important role in the growth of the alternative fuel industry, while the industry itself would have a major impact on many of the important decisions that will shape our futures.
Using Project-Based Education and Interactive Web Resources in Undergraduate Heat Transfer
Authors: Howell John
Published: November 2021

Two approaches to increasing student retention and interest have been implemented in the undergraduate heat transfer course at The University of Texas at Austin.

The first approach, under a Department-wide initiative in Project Based Education, is to assign a semester-long project that requires most of the basic material in the traditional heat transfer course to examine a practical engineering system. Three projects used to date will be briefly discussed.

Second, a series of web-accessible interactive modules has been constructed. The objective is to develop intuitive understanding of phenomena generally taught in the undergraduate heat transfer course. These modules allow students to vary the important aspects of a problem and immediately see the result. For example, one module demonstrates the characteristics of fins added to a surface to improve heat loss. Envision the handle on a frying pan; the student can vary the handle material, the cooling of the handle by increasing air flow velocity over it, etc. and see the temperature that results along the handle length. Such effects are difficult to show with chalk and talk. The instructor may also use the modules in class with computer projection to demonstrate these effects.

Nine modules have been developed to date. These demonstrate heat transfer by conduction through planar and cylindrical walls; heat transfer from materials with internal energy generation; fins; conduction in two-dimensional systems (under development); transient conduction in semi-infinite and finite-width slabs; convective heat transfer in flow over flat plates; convective heat transfer for flow in pipes; heat exchangers; and radiation in rectangular enclosures. Modules are programmed in JAVA for interactive use using any browser (Netscape or Explorer), and do not require a particular platform.
Multiple electron beam generation from InGaN photocathode
Authors: Sato Daiki , Shikano Haruka , Koizumi Atsushi , Nishitani Tomohiro , Honda Yoshio , Amano Hiroshi
Published: November 2021

In this study, we generated 25 multielectron beam (MEB) using an InGaN photocathode with a negative electron affinity state irradiating with 25 multilaser beam. The uniformity of the MEB and the total electron beam current were evaluated. A laser beam was split into 25 laser beams using a spatial light modulator. The coefficient of variation (CV) of laser power was 20%. The CV of quantum efficiency was 1.1%. The CV of electron beam current was 12%, and the total current was about 1.2 μA. These results will enhance the development of the MEB-defect inspection using the InGaN photocathode.
Born approximation of acoustic radiation force and torque on inhomogeneous objects
Authors: Jerome Thomas S. , Hamilton Mark F.
Published: November 2021

The Born approximation developed previously to model acoustic radiation force and torque exerted on homogeneous compressible objects of arbitrary shape [Jerome et al., J. Acoust. Soc. Am. 145, 36–44 (2019)] is extended to include objects that are inhomogeneous. The same general restrictions apply to this extended model, mainly that the incident field is not too similar to a progressive plane wave, that the material properties of the object do not differ substantially from those of the surrounding fluid, and that the size of the object is not much larger than a wavelength. Two applications of the model are presented, one for objects consisting of connected homogeneous regions with different material properties, and the other for objects with continuously varying material properties. Calculations are presented for spheres, finite cylinders, and prolate spheroids.
Tracking time differences of arrivals of multiple sound sources in the presence of clutter and missed detections
Authors: Gruden Pina , Nosal Eva-Marie , Oleson Erin
Published: November 2021

Acoustic line transect surveys are often used in combination with visual methods to estimate the abundance of marine mammal populations. These surveys typically use towed linear hydrophone arrays and estimate the time differences of arrival (TDOAs) of the signal of interest between the pairs of hydrophones. The signal source TDOAs or bearings are then tracked through time to estimate the animal position, often manually. The process of estimating TDOAs from data and tracking them through time can be especially challenging in the presence of multiple acoustically active sources, missed detections, and clutter (false TDOAs). This study proposes a multi-target tracking method to automate TDOA tracking. The problem formulation is based on the Gaussian mixture probability hypothesis density filter and includes multiple sources, source appearance and disappearance, missed detections, and false alarms. It is shown that by using an extended measurement model and combining measurements from broadband echolocation clicks and narrowband whistles, more information can be extracted from the acoustic encounters. The method is demonstrated on false killer whale (Pseudorca crassidens) recordings from Hawaiian waters.
Pupillary response to dynamic pitch alteration during speech perception in noise
Authors: Shen Jing
Published: November 2021

Dynamic pitch, also known as intonation, conveys both semantic and pragmatic meaning in speech communication. While alteration of this cue is detrimental to speech intelligibility in noise, the mechanism involved is poorly understood. Using the psychophysiological measure of task-evoked pupillary response, this study examined the perceptual effect of altered dynamic pitch cues on speech perception in noise. The data showed that pupil dilation increased with dynamic pitch strength in a sentence recognition in noise task. Taken together with recognition accuracy data, the results suggest the involvement of perceptual arousal in speech perception with dynamic pitch alteration.
The metabolic adaptation evoked by arginine enhances the effect of radiation in brain metastases
Authors: Marullo Rossella , Castro Monica , Yomtoubian Shira , Calvo-Vidal M. Nieves , Revuelta Maria Victoria , Krumsiek Jan , Cho Andrew , Morgado Pablo Cresta , Yang ShaoNing , Medina Vanina , Roth Berta M. , Bonomi Marcelo , Keshari Kayvan R. , Mittal Vivek , Navigante Alfredo , Cerchietti Leandro
Published: November 2021

Arginine enhances the effect of radiation in patients with brain metastasis by metabolic suppression of cancer cells.
Positive interactions are common among culturable bacteria
Authors: Kehe Jared , Ortiz Anthony , Kulesa Anthony , Gore Jeff , Blainey Paul C. , Friedman Jonathan
Published: November 2021

Positive interactions between bacteria, often described to be rare, occur commonly and primarily as parasitisms.
Two interacting transcriptional coactivators cooperatively control plant immune responses
Authors: Chen Huan , Li Min , Qi Guang , Zhao Ming , Liu Longyu , Zhang Jingyi , Chen Gongyou , Wang Daowen , Liu Fengquan , Fu Zheng Qing
Published: November 2021

EDS1 acts as a transcriptional coactivator that interacts with NPR1 and Mediator to promote plant defense.
Gut microbes may help malnourished children
Authors: Pennisi Elizabeth
Published: November 2021

Commonplace foods restore bacteria that can improve health.
Was our species in Europe 210,000 years ago?
Authors: Wade Lizzie
Published: November 2021

Skepticism greets startling conclusion from skull fragment found in Greek cave.
Late Pleistocene exploration and settlement of the Americas by modern humans
Authors: Waters Michael R.
Published: November 2021

How humans colonized the Americas

The arrival and spread of humans across the American continent is a research topic of abiding interest. Numerous archaeological finds in recent years have led to a reappraisal of the timing of the first occupations, before the Clovis culture of 13,000 years ago. Genetic research—especially genomic research over the past 5 years—also points to probable earlier dates for the founder populations that spread from Beringia ∼15,000 years ago. Waters reviews these research advances and provides signposts to the promise of future genomic studies for enriching our knowledge of the ancestral history of humans in the Americas.

Science
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Shape memory nanocomposite fibers for untethered high-energy microengines
Authors: Yuan Jinkai , Neri Wilfrid , Zakri Cécile , Merzeau Pascal , Kratz Karl , Lendlein Andreas , Poulin Philippe
Published: November 2021

Getting the most out of muscles

Materials that convert electrical, chemical, or thermal energy into a shape change can be used to form artificial muscles. Such materials include bimetallic strips or host-guest materials or coiled fibers or yarns (see the Perspective by Tawfick and Tang). Kanik
et al.
developed a polymer bimorph structure from an elastomer and a semicrystalline polymer where the difference in thermal expansion enabled thermally actuated artificial muscles. Iterative cold stretching of clad fibers could be used to tailor the dimensions and mechanical response, making it simple to produce hundreds of meters of coiled fibers. Mu
et al.
describe carbon nanotube yarns in which the volume-changing material is placed as a sheath outside the twisted or coiled fiber. This configuration can double the work capacity of tensile muscles. Yuan
et al.
produced polymer fiber torsional actuators with the ability to store energy that could be recovered on heating. Twisting mechanical deformation was applied to the fibers above the glass transition temperature and then stored via rapid quenching.

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Supplemental Material: Eocene fault-controlled fluid flow and mineralization in the Paradox Basin, United States
Authors: Bailey Lydia , al. et
Published: November 2021

Methods, notes, and supplemental tables and figures.
Erratum to: A New Mass Burial of Cave Bears (Carnivora, Ursidae, Ursus kanivetz, Vereshchagin, 1973) from the Middle Urals
Authors: Kosintsev P. A. , Gimranov D. O. , Lavrov I. A. , Kisagulov A. V.
Published: November 2021

An Erratum to this paper has been published: https://doi.org/10.1134/S0012496621050112
Effect modification by age of the association between obstructive lung diseases, smoking, and COVID-19 severity
Authors: Moschovis Peter P , Lu Mengdi , Hayden Douglas , Yonker Lael M , Lombay Jesiel , Taveras Elsie , Arauz Boudreau Alexy , Triant Virginia A , Foulkes Andrea S , Bassett Ingrid , Hibberd Patricia L , Kinane T Bernard
Published: November 2021

Introduction

Obstructive lung diseases (asthma and chronic obstructive pulmonary disease (COPD)) and smoking are associated with greater risk of respiratory infections and hospitalisations, but conflicting data exist regarding their association with severity of COVID-19, and few studies have evaluated whether these associations differ by age.

Objectives

To examine the associations between asthma, COPD and smoking on the severity of COVID-19 among a cohort of hospitalised patients, and to test for effect modification by age.

Methods

We performed a retrospective analysis of electronic health record data of patients admitted to Massachusetts General Hospital, assigning the maximal WHO Clinical Progression Scale score for each patient during the first 28 days following hospital admission. Using ordered logistic regression, we measured the association between maximal severity score and asthma, COPD and smoking and their interaction with age.

Measurements and main results

Among 1391 patients hospitalised with COVID-19, we found an increased risk of severe disease among patients with COPD and prior smoking, independent of age. We also found evidence of effect modification by age with asthma and current smoking; in particular, asthma was associated with decreased COVID-19 severity among older adults, and current smoking was associated with decreased severity among younger patients.

Conclusions

This cohort study identifies age as a modifying factor for the association between asthma and smoking on severity of COVID-19. Our findings highlight the complexities of determining risk factors for COVID-19 severity, and suggest that the effect of risk factors may vary across the age spectrum.
Engineered coastal berm-dune renourishment in New Jersey: can coastal communities continue to hold the line?
Authors: Kolodin Jesse , Lorenzo-Trueba Jorge , Hoagland Porter , Jin Di , Ashton Andrew
Published: November 2021

Following the significant coastal changes caused by Hurricane Sandy in 2012, engineered berm-dunes were constructed along the New Jersey coastline to enhance protection from future storms. Following construction, property values on Long Beach Island, NJ, increased in three beachfront communities. The projects were financed entirely through federal disaster assistance, but the percentage of future maintenance costs must be covered by local communities. Whether communities are willing or capable of financially contributing to maintenance remains unclear because (i) some homeowners prefer ocean views over the protection afforded by the berm-dune structures, and (ii) stakeholder risk perceptions can change over time. To investigate the relationships between berm-dune geometries, values of coastal protection, and ocean view values, we developed a geoeconomic model of the natural and anthropogenic processes that shape beach and dune morphology. The model results suggest that coastal communities may exhibit significant differences in their capabilities to maintain engineered dunes depending on stakeholder wealth and risk perception. In particular, communities with strong preferences for ocean views are less likely to maintain large-scale berm-dune structures over the long term. If these structures are abandoned, the vulnerability of the coast to future storms will increase.
Potential of typical highland and mountain forests in the Czech Republic for climate-smart forestry: ecosystem-scale drought responses
Authors: Jocher Georg , Kowalska Natalia , Acosta Manuel , Krejza Jan , Marková Irena , Marshall John D. , Uchytilová Tereza , Pavelka Marian , Marek Michal V.
Published: November 2021

Climate-smart forestry (CSF) consists of an extensive framework of actions directed to mitigating and adapting to global climate change impacts on the resilience and productivity of forest ecosystems. This study investigates the impact of the pan-European 2018 drought on carbon exchange dynamics in typical highland and mountain forests in the Czech Republic, including two coniferous stands (Norway spruce at Bílý Kříž and Rajec) and one deciduous stand (European beech at Štítná). Our results show that the annual net ecosystem CO2 uptake at Rajec decreased by 50% during the drought year in comparison to a reference year with normal climatic conditions. The Bílý Kříž stand is less affected by drought, as the local microclimate ensures sufficient water supply. The European beech forest at Štítná is most resilient against drought and its negative impacts — there we detect no differences in carbon exchange dynamics between the drought year and the reference year. We consider the matching of tree species to site conditions as crucial in the context of CSF, specifically regarding the stand response to water limitation and water supply and demand. Successively replacing spruce with beech trees in areas with high water demand but limited water supply, like Rajec, will support the goals of CSF.