Geothermal cooling via a closed-loop thermal heat sink system shows promise in improving solar performance in hot regions.

Geothermal cooling via a closed-loop thermal heat sink system shows promise in improving solar performance in hot regions. 
 
Finding ways to enhance and improve the efficacy of photovoltaic (PV) systems is critical as the use of green power solutions continues to grow around the world. The concept behind one such solution to improve the performance of photovoltaic solar modules came to Ignacio Valiente-Blanco, a mechanical engineering professor in the Department of Signal Theory and Communications at the University of Alcalá (UAH) in Madrid, when he was hiking in the mountains near his home in Spain.

Cool Water Boosts Solar Efficiency

Conductive flakes enable an economical additive manufacturing method to yield results.

Conductive flakes enable an economical additive manufacturing method to yield results. 
&nbsp; 
&nbsp; 
The standard manufacturing and assembly processes for heat exchangers can be expensive and time-consuming. They also limit the geometric configurations that can be considered during the design process. 
Additive manufacturing (AM), when viable, can be a more efficient manufacturing process and gives engineers much more design freedom, often allowing them to create features that standard machining cannot. 
Researchers are looking for ways to build high-performance heat exchangers using AM. However, most metal-based AM processes are so expensive that commercial production is not viable. 
Looking to see if another approach might work, a research team led by Gregory F. Nellis, a professor at the University of Wisconsin (UW), designed and built an efficient and cost-effective heat exchanger using lower-cost, deposition-based AM processes. The team successfully printed a heat exchanger using fused deposition modeling that has sufficient thermal conductivity to outperform standard heat exchangers, at a more affordable cost.

Printing Better, Cheaper Heat Exchangers

Using Smart Trains to Find Defective Rails

Use of additive manufacturing (AM) has exploded since its conception over 40 years ago. With more and more eyes looking skyward, from space tourism to NASA&rsquo;s return to the moon, the potential AM holds for use in orbit and beyond is notable. &nbsp; 
 
But the &ldquo;future of space exploration is dependent on technologies that maximize mission endurance and self-sufficiency. As missions venture further away from Earth, resupply logistics fail to accommodate the probability of component failure and uncertainty about which component may fail,&rdquo; according to &ldquo;In-Space Additive Manufacturing: A Review,&rdquo; published in ASME&rsquo;s Journal of Manufacturing Science and Engineering in February. 
 
n-space manufacturing (ISM), of which in-space additive manufacturing (ISAM) is a part, is a promising solution, the study suggests, which would integrate repair and fabrication techniques into space missions, &ldquo;providing on-demand capabilities to adapt to unforeseen situations.&rdquo; &nbsp; 
 
The study provides a literature review of ISAM and its related technologies and summarizes numerous studies available on this subject, while also discussing ISAM and identifying knowledge gaps. 
 
Lead author Miguel Hoffmann, a doctoral student at the Wm Michael Barnes &lsquo;64 Department of Industrial and Systems Engineering at Texas A &amp; M University, and principal investigator Alaa Elwany, associate professor and ASME Foundation Swanson Fellow, College of Engineering Eugene Webb Faculty Fellow, and director of the Texas A&amp;M Metal Additive Manufacturing Research Laboratory (AMTex), recently shared some additional insights on ISAM and what may lie ahead.

Francesco Lanza di Scalea, professor of experimental mechanics, NDE and SHM Laboratory, Department of Structural Engineering, University of California, San Diego, La Jolla, Calif., discusses the use of ultrasonic high-speed inspection of train track rails to detect internal defects and potentially avoid costly damages.

Miguel Hoffmann and Alaa Elwany of Texas A&amp;M University discuss the prospect of manufacturing in orbit and beyond.

Better Grip for Laparoscopy

To pull objects from the tightest spaces, researchers devise a clever little claw.

To pull objects from the tightest spaces, researchers devise a clever little claw.

April-June 2023

New research from the University of Salerno provides methods on how to detect and protect connected vehicles from cyberattacks.

<var>What if your car was as vulnerable to hack into as your laptop? The reality is cars today are basically a computer on wheels. According to Car and Driver, 40 percent of a new car&rsquo;s cost is driven by electronic components. The New York Times reported that a modern vehicle could contain more than 3,000 computer chips. Electronics are such an essential part of a car&rsquo;s design that the shortage of semiconductors due to supply chain disruption from the pandemic has impacted auto assembly lines worldwide, creating a lack of new vehicles on the market.</var> 
 
By introducing computer systems into vehicles, hackers have found ways to exploit their vulnerabilities. In 2015, Black Hat security researchers Charlie Miller and Chris Valasek hacked a Jeep Cherokee via its infotainment system. Miller and Valasek exploited how the vehicle autogenerated its Wi-Fi password based on the time when the car&rsquo;s multimedia system would turn on. Through the infotainment system, the hackers could manipulate the air conditioner, the radio, the windshield wipers, and even the transmission. On a road test with Wired magazine, the hackers cut the transmission as the vehicle was driving 70 mph on the highway. This past February, German teenager David Colombo identified a vulnerability in the TeslaMate, a third-party application used by Tesla owners to analyze car performance. By hacking the app, Colombo was able to unlock doors, turn on and off the headlights, and control the radio. He was even able to track in real-time the location of the car.

Advancing Cybersecurity in Connected Vehicles

Explore how adverse weather conditions can impact autonomous vehicles&rsquo; lidar cameras.

<var>Lidar, or light detection and ranging, is a popular remote sensing method used for measuring the exact distance to an object. These imaging systems are increasingly used in the development of autonomous vehicles (AVs). However, final technology implementation cannot yet be achieved because major AV manufacturers are only now starting to select providers for data collection units that can be introduced in commercial vehicles.</var> 
One of the biggest unknowns in the development of AVs is how adverse weather conditions challenge the development of safe and reliable advanced autonomous systems for sensing and perception. How does the diffraction of light through rain, fog, and snow limit lidar performance?

How Self-Driving Cars See in Extreme Weather

Interview with Luca Capriotti

Luca Capriotti, former president of the International Youth Nuclear Congress, shares his passion for nuclear energy and beliefs that it can become a viable, safe power source to be used globally and responsibly in the future.

The Future of Power is Nuclear

Infographic: Sodium-Cooled Fast Reactor

<var>Most nuclear reactors in operation today use water as a coolant, but one promising alternative looks to replace water with liquid sodium. Sodium can be heated to high temperatures before boiling, which means that a sodium-cooled reactor can operate at atmospheric pressure and can use a thinner reactor vessel. These reactors also will produce less radioactive waste. Explore the diagram of a sodium-cooled fast reactor below.</var>

Sodium-Cooled Fast Reactor

July-September 2022

<var>Using 3D scanning, 3D simulation, and CAD, engineers at the Queensland University of Technology have created a patient-specific contoured mattress that successively supports patients in the operating room.</var>
Paige Little is an expert on using state-of-the-art imaging technology to understand ideal body position and support for enhancing the quality of sleep. It&rsquo;s the kind of research used to improve beds for the home. But in 2018, Little was contacted by a consultant who asked for something more serious. Could she design a customized, patient-specific surgical mattress for a 10-year-old about to undergo spinal surgery?

The patient had Morquio syndrome, a disorder that causes skeletal abnormalities and neuromuscular scoliosis. She would need to lie safely on her stomach and the front of her body for the duration of the surgery.

&ldquo;Intraoperative patient position is always a critical factor in spinal surgery, particularly in the case of prone patient positioning, where the anatomy and physiology of the torso is such that additional pressure may have adverse effects on the cardiopulmonary system as well as causing skin and muscle necrosis,&rdquo; Little said. &ldquo;Optimal patient positioning for spine surgery is vital for surgical success and the minimization of complications intra and postoperatively.&rdquo;

Little, an associate professor at the school of mechanical, medical, and process engineering at Queensland University of Technology, is up to the challenge. Using an innovative digital workflow involving 3D surface scanning, 3D simulation and computer-aided design (CAD), she successfully created a customized theater mattress with the patient&rsquo;s specific body-contour requirements. The operation was a success, and the surgical team praised the mattress and its positive impact on patient outcome.
<img alt="" src="~/getmedia/3cd9331a-8fc6-47de-8bf9-c54a38524afa/patient-img1.jpg" /> <var>Dr Paige Little at Research Centre Qld Children&rsquo;s Hospital.</var>

<h5>Patient-specific design</h5>

Little&rsquo;s goal was to create a customized mattress to hold the patient safely and reduce possible skin damage during the surgery procedure. By using digital simulation tools and CAD, she was able to create a patient-specific surgical mattress that fit the contours of the patient&rsquo;s body. This made it easier for the surgeon to relieve load bearing on prominent anatomical features during the surgery because the support surface was tailored to the patient&rsquo;s anatomy for the lengthy procedure.

&ldquo;The design process is based in CAD, and for many of the mattresses I have designed, I use Solidworks to create the mattress contours,&rdquo; Little said. &ldquo;We have recently explored the use of CNC machining to create the surface contours in the polyurethane foam, and with high spindle speeds it is possible to machine this foam using standard tooling. The machining is very successful with well-defined surface contours, and relatively little post-process cleaning is needed to remove dust waste. The foams do not require freezing to machine them. They also do not release toxic fumes or particulate matter.&rdquo;

Topographic scanning of the entire patient was required to create a mattress contour. &ldquo;The contour is not a replica of the patient&rsquo;s anatomy, but rather is custom-designed using the topographic scan as a basis,&rdquo; Little said. &ldquo;The design process cannot be parameterized&mdash;the design is created for each patient using CAD methods to alleviate pressure on the skin surface over areas that are delicate, or regions of the anatomy that cannot bear load for long periods of time. For some corrective surgeries, the patient may be lying stationary for many hours.&rdquo;

Manufacture is currently a manual, just-in-time process. The process may benefit from CNC machining or robotic manufacturing, especially for mattress contours that are for large or tall individuals or have deep cutouts and/or overhangs.

Sealy of Australia then manufactured the final mattress product. Technicians used the 3D model to hand-cut and piece together multiple layers of soft hypo-allergenic foam to conform exactly to the patient&rsquo;s anatomy.

The custom mattress is effectively contoured to the patient&rsquo;s anterior anatomy during surgery. Intraoperative monitoring indicated the patient was not under undue cardiovascular strain over the course of the operation &ldquo;and she successfully remained in the prone position for the entire eight-hour operation,&rdquo; Little said. &ldquo;Immediately postoperatively, there was no evidence of excessive interface pressure between the patient and the support, suggesting the custom-fit mattress successfully distributed the patient&rsquo;s body weight, alleviating regions of excessive pressure.&rdquo;
<img alt="" src="~/getmedia/a3cf9bdb-f951-4224-a7dc-5c8ec7269b24/patient-img2.jpg" /><var>Sealy of Australia R&amp;D manager Daniel Green exams form that contours to the patient&rsquo;s torso.</var>

<h5>Moving Forward</h5>

Since the first use of the surgical mattress, Little has designed 11 other supportive mattresses for pediatric patients with unique anatomies requiring support during surgery&mdash;all with successful results.

The next step is to continue showcasing the mattresses to a broader clinical audience so other patients can benefit from the use of customized body supports during surgery. &ldquo;Their surgical teams will also gain confidence in reducing the risks of complications due to extended periods of weight-bearing in patients with unique conditions,&rdquo; Little said.

The digital workflow she used to design the mattresses can also be applied to the design and advanced manufacturing of other custom-fit devices to assist in treatment and/or rehabilitation of patients. &ldquo;These same techniques&mdash;3D topographic scanning, 3D simulation, and CAD methods&mdash;can be applied to the design of customized corrective/rehabilitation orthoses,&rdquo; Little said, &ldquo;or to the custom design of supports for radiation therapy to ensure the patient is positioned in a repeatable position between treatment appointments.&rdquo;

Using 3D scanning, 3D simulation, and CAD, engineers at the Queensland University of Technology have created a patient-specific contoured mattress that successively supports patients in the operating room.

<var>Using 3D scanning, 3D simulation, and CAD, engineers at the Queensland University of Technology have created a patient-specific contoured mattress that successively supports patients in the operating room.</var>

Paige Little is an expert on using state-of-the-art imaging technology to understand ideal body position and support for enhancing the quality of sleep. It&rsquo;s the kind of research used to improve beds for the home. But in 2018, Little was contacted by a consultant who asked for something more serious. Could she design a customized, patient-specific surgical mattress for a 10-year-old about to undergo spinal surgery?

The patient had Morquio syndrome, a disorder that causes skeletal abnormalities and neuromuscular scoliosis. She would need to lie safely on her stomach and the front of her body for the duration of the surgery.

&ldquo;Intraoperative patient position is always a critical factor in spinal surgery, particularly in the case of prone patient positioning, where the anatomy and physiology of the torso is such that additional pressure may have adverse effects on the cardiopulmonary system as well as causing skin and muscle necrosis,&rdquo; Little said. &ldquo;Optimal patient positioning for spine surgery is vital for surgical success and the minimization of complications intra and postoperatively.&rdquo;
Little, an associate professor at the school of mechanical, medical, and process engineering at Queensland University of Technology, is up to the challenge. Using an innovative digital workflow involving 3D surface scanning, 3D simulation and computer-aided design (CAD), she successfully created a customized theater mattress with the patient&rsquo;s specific body-contour requirements. The operation was a success, and the surgical team praised the mattress and its positive impact on patient outcome.

Patient Support Via Customized Surgical Mattresses

<var>Hydrogen seems like an ideal fuel, but a feasibility analysis reveals the factors that will determine its success.</var>
Hydrogen has the highest energy density by weight of any fuel. So it only makes sense that compressed hydrogen gas is being considered as a carbon-free replacement for diesel in heavy-duty trucks. A hydrogen-fueled truck fleet would substantially reduce greenhouse gas emissions and other pollutants from the freight industry.

Before that can happen, engineers need to work out the optimum technology to make hydrogen economical as well as clean.

​&ldquo;Hydrogen technology is currently expensive because of relatively low deployment. Once it is more common, the refueling infrastructure cost should decrease significantly. Hydrogen refueling infrastructure can be implemented immediately. It has the potential to be very economical,&rdquo; said Wahiba Yaici, a research scientist at the CanmetENERGY Research Centre, Natural Resources Canada in Ottawa, Ontario.

The cost of hydrogen itself looms as the main element in the acceptance of compressed hydrogen. It is rarely found isolated and must go through processes to extract it. Each hydrogen production method involves separating hydrogen from some compound. Common extraction processes include natural gas reforming, biomass gasification, and coal gasification. So-called green hydrogen is produced by using renewable energy such as solar and wind to power the electrolysis of water or other hydrogen-making reactions.
<img alt="A truck cab with visible hydrogen fuel tank" src="~/getmedia/c92a71b0-061d-466a-b7d5-8b3ffeabf1ff/hydrogen-img1.jpg" /><var>Generally, green hydrogen is more expensive than hydrogen produced by other methods, but it also has the advantage of producing zero carbon emissions.</var>

Storing hydrogen is another issue. Hydrogen at a fueling station can be stored either as a gas or a liquid. Storing hydrogen as a gas typically requires high-pressure tanks at 5,000 to 10,000 psi. Storage as a liquid requires cryogenic temperatures, as the boiling point of hydrogen at one atmosphere pressure is &minus;252.8 &deg;C (-423 &deg;F).

The main options for onboard hydrogen storage in vehicles are gaseous storage at 5,000 psi or at 10,000 psi in thermally insulated tanks or in materials with superior chemical properties, like metal hydrides or organic compounds,&rdquo; Yaici said.

To address the hydrogen refueling scenario for big trucks, Yaici teamed with Michela Longo, an associate professor at the Politecnico di Milano in Italy, to write a paper, &ldquo;Hydrogen Gas Refueling Infrastructure for Heavy-Duty Trucks: A Feasibility Analysis,&rdquo; for the ASME Journal of Energy Resources Technology. Both authors are mechanical engineers. The pair chose to pursue hydrogen because it can be used as fuel in modified internal combustion engines (ICEs), reducing the need to purchase new vehicles. Existing diesel engines can easily be modified to burn hydrogen. This is in contrast to the fuel-cell-powered vehicles most people think of when talking hydrogen; fuel cells combine hydrogen and oxygen, yielding water, heat, and electricity used to power an electric motor that drives the vehicle.

This paper investigates the feasibility of developing a nationwide network of hydrogen refueling infrastructure to help convert the long-haul, heavy-duty (LHHD) truck fleet from diesel fuel to hydrogen. Diesel is currently the main fuel used to transport freight over the road.

The team carried out a technical analysis to estimate the number of hydrogen refueling stations needed to convert the fleet of LHHD vehicles to hydrogen. They also did an economic analysis to evaluate the final selling price of hydrogen.

According to Yaici, &ldquo;Results from the techno-economic study showed that hydrogen prices can vary significantly.&rdquo; On average, they found hydrogen to cost 239 percent more than diesel due to the diverse costs of the various production methods for hydrogen. Hydrogen also has about 2.6 times the energy density of diesel fuel by weight, which serves as an equalizer. Energy density by volume is another matter because at the operating temperature of trucks, diesel is a liquid while hydrogen is a gas, giving it a lower energy density by volume if it is not liquefied by cryogenics. Regardless of the hydrogen production method, the process can occur at a central facility or locally where it is needed.

&ldquo;A central system can increase the scope of production by producing hydrogen at large facilities that take advantage of bulk processes to reduce costs per unit,&rdquo; Yaici said. &ldquo;Nevertheless, hydrogen must be transported to its destination via pipeline or trucks. This will increase the operational fees. A distributed process, one where hydrogen is produced on demand locally, eliminates the need to deliver hydrogen over long distances.&rdquo;
<img alt="A hydrogen &quot;gas&quot; pump accompanied by a small array of solar panels" src="~/getmedia/7f96ca95-97e5-4062-9f56-5da4b3d880e5/hydrogen-img2.jpg" />
Hydrogen stations are built to refuel vehicles in similar manner to those used by diesel stations. Each refueling station will consist of a compressor, storage tanks, and at least one dispenser. Yaici pointed out the versatility of the feasibility study. &ldquo;The methodology and models proposed can be used for studying the techno-economics of hydrogen refueling stations in any country and for other types of ICE fleets or fuel cell vehicles,&rdquo; he said.

This includes refueling stations for vehicle fleets powered by renewable fuels such as renewable natural gas or biofuels. Engineering analyses such as this one will help shape the future of transportation.

Hydrogen seems like an ideal fuel, but a feasibility analysis reveals the factors that will determine its success.

<var>Hydrogen seems like an ideal fuel, but a feasibility analysis reveals the factors that will determine its success.</var>
Hydrogen has the highest energy density by weight of any fuel. So it only makes sense that compressed hydrogen gas is being considered as a carbon-free replacement for diesel in heavy-duty trucks. A hydrogen-fueled truck fleet would substantially reduce greenhouse gas emissions and other pollutants from the freight industry.

Before that can happen, engineers need to work out the optimum technology to make hydrogen economical as well as clean.

Putting Hydrogen to the Economic Test

Interview with Moncef Krarti

Moncef Krarti, head of the Building System Program at the University of Colorado, Boulder, discusses ways to turn down the temperature on hot, overcrowded urban areas.

Cooling Cities by Combating Heat Islands

Infographic: Pneumatic Help for Grasping

<div class="infogram-embed" data-id="_/JNK9h2xLuaalwUNVZqrN" data-title="Pneumatically-Powered Help for Grasping" data-type="interactive">&nbsp;</div>
 
&nbsp;

Researchers hope this pneumatic grip glove could soon help relieve industrial workers of some pain.

Workers who must repeat forceful actions with their hands&mdash;whether operating industrial hand tools or typing on a keyboard&mdash;are often subject to carpal tunnel syndrome and other cumulative trauma disorders, which not only are painful but also diminish grip strength. Naveen Chandrashekar, a professor of mechanical and mechatronics engineering at the University of Waterloo in Ontario, and graduate student Daniel Loewen, now chief technology officer at ioAirFlow in Winnipeg, looked for a way to reduce the force needed by workers operating hand tools, which would lean to less wear and tear on the hands and wrists.

Pneumatic Help for Grasping

October-December 2022

Through a complete review of published research over the last 60 years, researchers aim to propel development of new head injury metrics forward.

<var>Through a complete review of published research over the last 60 years, researchers aim to propel development of new head injury metrics forward.</var>

Metrics that help engineers design safer helmets and vehicles to prevent fatalities went mostly unchanged for about 50 years. Now, researchers are looking for better metrics to help prevent brain injuries&mdash;from mild concussions to traumatic damage.

In &ldquo;A Review of Head Injury Metrics Used in Automotive Safety and Sports Protective Equipment,&rdquo; published in the ASME Journal of Biomedical Engineering, authors Stefan Duma and Bethany Rowson examined every major metric that has been published over the past 60 years, including some of the original work done at Wayne State University in the 1960s and 1970s that examined skull fractures and were used for early football helmet and vehicle design standards. This effort summarizes existing head injury metrics and their applications for head and brain injuries.

Duma is Harry C. Wyatt Professor of Engineering and director of the Institute for Critical Technology and Applied Science (ICTAS) at Virginia Tech and Rowson is a former Virginia Tech research assistant professor. The team defined a metric as any variable or combination of variables that is &ldquo;used to assess injury severity, while a criterion is any quantitative value that is considered a threshold for injury or is assigned a predicted risk of injury.&rdquo;

The Virginia Tech team has about 30 years of history in automobile safety. About 20 years ago, they started working more in the sports and football area. Today, about 40 faculty and students at Virginia Tech work on brain-related research.

Advancing Head Injury Metrics Research

Researchers at Vanderbilt University have invented a nitrogen gas-powered thruster that is worn on the back that can correct falls as they start, restoring balance and averting potential injury.

<var>Researchers at Vanderbilt University have invented a nitrogen gas-powered thruster that is worn on the back that can correct falls as they start, restoring balance and averting potential injury.</var>

Falls can lead to severe and fatal injuries, particularly for elderly people. According to the U.S. Centers for Disease Control and Prevention, millions of people fall each year, with one in five suffering serious injury.

Michael Goldfarb, a professor of mechanical engineering at Vanderbilt University, has first-hand experience dealing with this health risk. &ldquo;As my parents grew older, both had experiences with fall risk that really limited their quality of life,&rdquo; he said. &ldquo;My father, in particular, had Parkinson&rsquo;s disease.&rdquo;

Goldfarb began thinking about new ways to correct occasional states of imbalance. Robotic exoskeletons can offer balance assistance, but have design challenges, such as having to coordinate a recovery response with the user. To avoid requiring a large frame or other structure (which would impede independence), he decided to focus on building a backpack-worn system that can apply forces directly to a person&rsquo;s body using a thruster.

&ldquo;This research challenge seemingly has not received much attention and therefore there were a lot of unknowns,&rdquo; Goldfarb said. &ldquo;Correcting a fall is a shared task between the person falling and the device helping to arrest the fall. What is the distribution of shared effort? How much force is appropriate to correct an impending fall? For how long is the force required? Can the magnitude of assistance required be provided by a compact cold-gas thruster?&rdquo;

Goldfarb and fellow researchers Almaskhan Baimyshev and Michael Finn-Henry then set out to create a lightweight, cold-gas thruster (CGT) jetpack that senses when a fall has been initiated and can provide a restoring force to help the person recover his or her balance.

Backpack Could Reduce the Risk of Fall

Paul P. Palies, director of the Combustion and Propulsion for Aviation Research Center at the University of Tennessee Space Institute, discusses the prospects for fueling aircraft with hydrogen.

Flying with Hydrogen

Ro-Bats, Bat-Bots, and Other Bat-like Robots

For these engineers, the allure of biologically inspired flight still remains strong.

January-March 2023

Silicate-based glasses have several physical and chemical properties that make them preferred manufacturing materials, such as high thermal and chemical stability, stiffness, and high optical transparency. They are also relatively low cost. 
&nbsp; 
However, glasses can also be hard to work with; For example, there are difficulties in precisely controlling heat and pressure. The standard methods for making glass objects tend to be slow and expensive, especially for more complex pieces and shapes that take more time and require greater precision. 
&nbsp; 
These challenges might compel engineers to try established additive manufacturing (AM) technologies instead for creating transparent glass pieces; however, these methods also have material challenges (for example, the high molten viscosity of glass limits bubble consolidation and release in powder bed processes). 
&nbsp; 
To improve the viability of 3D-printing glass objects, researchers at the University of Notre Dame have developed a new AM method that can 3D-print hollow glass tubes using a unique digital glass-forming (DGF) process that is more accurate and efficient than existing methods. 
&nbsp; 
They published their results in the paper, &ldquo;Printing Hollow Tubes Using Digital Glass Forming,&rdquo; in the January 2023 issue of Journal of Manufacturing Science and Engineering. 
 
&nbsp; 
<img alt="A spiral ball made from a printed glass tube." src="~/wwwasmeorg/media/Magazines/RDPulse/Summer-2023/3D-printing-with-glass-tubes-article-image-1.png" style="height:750px;width:797px;" /> 
A spiral ball made from a printed glass tube is filled with fluorescent fluid. 
Credit: Capps, et al. 
 
 
How It Works 
&nbsp; 
&ldquo;The DGF process uses a laser to locally heat continuously fed glass feedstock so that it can be plastically deformed,&rdquo; said team member Edward Kinzel, associate professor of aerospace and mechanical engineering at at the university. &ldquo;This allows it to be bent and deposited onto a workpiece.&rdquo; 
 
The workpiece is positioned relative to the laser using precision four-axis computer numerical control stages. The intersection between the laser and the feedstock remains stationary, while a glass substrate of the same material is moved into position, allowing the two materials to be fused. 
&nbsp; 
The deposition process is monitored in situ by several instruments, &ldquo;including infrared and visible cameras to monitor the temperature and morphology at the process zone,&rdquo; Kinzel said. &ldquo;The feedstock is guided to the process zone from the feeder through a steel tube that minimizes the deflection of the glass.&rdquo; 
&nbsp; 
The DFG process can use hollow tube feedstock instead of solid glass cane; however, tubes are prone to collapsing during the deposition process. By pressurizing the tube with air, it can be kept open during deposition. Even so, there are still challenges fusing tubes to a workpiece due to overheating, which can result in a blowout. 
&nbsp; 
After discussions with Kiva Ford, a professional scientific glass blower at the university, the system was re-configured so that the CO2 laser is delivered from the side and directly heats the intersection of the feedstock/workpiece. 
&nbsp; 
Bending the glass into the desired shape is the result of interactions among mechanical forces, load rates, and temperature-dependent material properties, all of which must be controlled to create complex geometries with constant diameter tubes. 
&nbsp; 
&ldquo;By applying a pneumatic pressure to the inside of the tube, these collapsing forces can be resisted,&rdquo; Kinzel said. &ldquo;Loading on the laser-heated region is controlled by the stages as well as pneumatic pressure in the tube, which allows the printing of complex shapes without the tube collapsing.&rdquo; 
&nbsp; 
Although glasses with different chemistries can be fused, the coefficient of thermal expansion for the feedstock and the substrate must be compatible to avoid the creation of thermal stress/shock upon cooling. If thermal stress is present, it can be removed by heating the substrate and cooling it down, followed by a post-deposition annealing process. 
&nbsp; 
Using this digital glass-forming process, Kinzel and his team successful created fully dense transparent parts including lenses, freestanding structures from filaments, and waveguides from optical fiber feedstock. They also printed open channels in both 2D and 3D freestanding structures. 
&nbsp; 
&ldquo;From these experimental results, the important features of both on-substrate and free-space deposition can be combined, allowing for the creation free-standing complex shapes,&rdquo; Kinzel said. 
&nbsp; 
The digital glass-forming process requires the management of significant reaction forces. This is due to the high viscosity of the glass, even when it is molten. 
&nbsp; 
&ldquo;These forces can make the process more challenging&mdash;for example, deflection of the filament relative to the laser during printing free-standing structures,&rdquo; Kinzel said. &ldquo;Our method also affords significant control of the molten region through the ability to control the diameter of tubes pneumatically.&rdquo; 
 
 
<img alt="Four-leaf clover 3D printed in glass." src="~/wwwasmeorg/media/Magazines/RDPulse/Summer-2023/3D-printing-with-glass-tubes-article-image-2.png" style="height:590px;width:897px;" /> 
The researchers printed this four-leaf clover using the method they pioneered. 
Credit: Capps, et al. 
 
 
Moving Forward 
&nbsp; 
By adding pneumatic pressure, the digital glass forming process allows the printing of smooth, open tube structures. These can be fused to a substrate or freestanding structures, with the ability to control the open tube area by altering the processing parameters for the glass deposition (power, feed rate, pressure). 
&nbsp; 
&ldquo;Our work shows the ability to scale some of the traditional scientific glass blowing processes to small scales with computer numerical control,&rdquo; Kinzel said. 
&nbsp; 
The research team is currently working to improve the speed of the process. This includes volumetric heating of the glass as well as co-axial heating. They continue to improve the precision of the process and are adding closed loop feedback control, as well as the track morphology, the track locations (particularly for freestanding structures), and surface form for dense structures. &ldquo;We are working on printing photonics,&rdquo; Kinzel said, &ldquo;including integrating microfluidics.&rdquo; 
&nbsp; 
Other research is focused on the range of free-standing structures such as lattices that can be deposited, as well as the types of glasses and other AM materials that can be used with this method. 
&nbsp; 
Mark Crawford is a technology writer in Corrales, N.M. 
&nbsp;

Using pneumatic pressure inside of the tube to keep it open, researchers develop a new way to manufacture glass components.

Silicate-based glasses have several physical and chemical properties that make them preferred manufacturing materials, such as high thermal and chemical stability, stiffness, and high optical transparency. They are also relatively low cost. 
&nbsp; 
However, glasses can also be hard to work with; For example, there are difficulties in precisely controlling heat and pressure. The standard methods for making glass objects tend to be slow and expensive, especially for more complex pieces and shapes that take more time and require greater precision. 
&nbsp; 
These challenges might compel engineers to try established additive manufacturing (AM) technologies instead for creating transparent glass pieces; however, these methods also have material challenges (for example, the high molten viscosity of glass limits bubble consolidation and release in powder bed processes).

3D Printing with Glass Tubes

Over the past two decades, wind power has become an increasingly important source of electricity worldwide, and large, three-bladed turbines are a familiar sight. While most of those blades are formed as a simple airfoil, researchers have been studying whether new shapes could yield greater performance. 
&nbsp; 
<img alt="Winglets" src="~/getmedia/2b142444-eeac-4c5a-8c52-734effb4094a/Cutting-Wind-Image_1.jpg" /> 
 
The team added winglets and tubercles to wind turbine blades to test their effect on the efficiency of wind turbines. 
&nbsp; 
For instance, winglets&mdash;extensions to the tip to guide tip vortices rolling off the end of the wing in a manner that increases lift and reduce induced drag &mdash;have been used on aircraft for decades to improve performance. And recent research into tubercles, which are small protuberances such as the kind found on the flippers of whales, has shown some promising results in improving airfoil aerodynamics. The tubercles are thought to channel the airflow over the airfoil into more narrow streams, creating higher velocities and more lift, while at the same time reducing drag due to wingtip vortices. 
&nbsp; 
A team at the University of Wisconsin-Milwaukee led by Ryoichi S. Amano has looked into the effect of adding both of these features onto a standard wind turbine blade. Their research was published in the ASME Journal of Energy Resources Technology in January 2023. 
&nbsp; 
Using both computational fluid dynamics models and physical experiments in an on-campus wind tunnel, the team studied an 8-inch-wide, three-bladed turbine with a relatively new airfoil shape, one that features a higher lift-to-drag ratio, lower thickness, and more curvature than other commonly employed shapes. After getting baseline readings in the wind tunnel, the team developed a CFD model of an 80-foot-diameter turbine, and then modified the model to add winglets and tubercles. 
&nbsp; 
The various configurations were simulated at wind speeds of 7.5 m/s, 12.5 m/s, and 17.5 m/s, or 17 mph, 28 mph, and 39 mph, respectively. 
&nbsp; 
Compared to the unaltered airfoil, adding winglets improved power output and efficiency at all wind speeds. The best-performing winglet bent 60 degrees from the plane of the blade; turbines with blades featuring that winglet showed power improvement by between 8 percent and 10 percent. 
&nbsp; 
<img alt="Tubercles" src="~/getmedia/f8054642-a1e8-4f44-8cd1-83de6ed844c6/Cutting-Wind-Image_2.jpg" style="height:1177px;width:900px;" /> 
 
The team tested five different sets of tubercles. Only the fourth one shown had any positive impact. Winglets angled at 30, 60, and 90 degrees were also tested. 
&nbsp; 
The performance of the tubercles was not so promising. The team tried out five different configurations of various degrees of coarseness. Four of the five demonstrated much worse power production compared to the baseline blade. One set of small and finely spaced tubercles did improve the aerodynamics of the blades, though it was a fraction of what the winglets provided. 
&nbsp; 
<img alt="This model shows the vortices shed by the tip of the wind turbine blade." src="~/getmedia/01548883-673f-4912-8192-d168aa0c2ae3/Cutting-Wind-Image_3-inverse.jpg" />&nbsp; 
 
This model shows the vortices shed by the tip of the wind turbine blade as it turns in the wind. Since vortices produce drag on the airfoil, the goal of the research was to find shapes that kept vortices from shedding off the broad surface of the blade. 
 
To test whether the combination of the two features might lead to better results, the team added the three winglet types to four of the tubercle configurations. For each wind speed, the performance of the winglet-tubercle combination was worse than that of the tubercle or the winglet by itself. The researchers concluded that the issue was that the mechanisms the two features used to improve aerodynamics interfered with each other. In their paper, the team wrote, &ldquo;When tubercles are incorporated with a winglet on the same blade, the tubercle&rsquo;s mechanism of enhancing the chordwise flow interferes with the ability of the winglet to move the tip vortex away from the rotor plane toward the wake&rsquo;s downstream direction and hence the inefficient reduction of induced drag on the blade.&rdquo; 
&nbsp; 
Just as with commercial aircraft, it seems possible that wind turbine blades could sport winglets to improve performance in the coming years. But don&rsquo;t expect to see bumpy blades anytime soon. 
&nbsp; 
Jeffrey Winters is editor in chief of Mechanical Engineering magazine. 
&nbsp;

The efficiency of wind turbines depends on how smoothly they can slice through the air. Can combining new blade shapes produce superior results?

Over the past two decades, wind power has become an increasingly important source of electricity worldwide, and large, three-bladed turbines are a familiar sight. While most of those blades are formed as a simple airfoil, researchers have been studying whether new shapes could yield great performance.

Cutting Through the Wind

Use of additive manufacturing (AM) has exploded since its conception over 40 years ago. With more and more eyes looking skyward, from space tourism to NASA&rsquo;s return to the moon, the potential AM holds for use in orbit and beyond is notable. 
&nbsp; 
But the &ldquo;future of space exploration is dependent on technologies that maximize mission endurance and self-sufficiency. As missions venture further away from Earth, resupply logistics fail to accommodate the probability of component failure and uncertainty about which component may fail,&rdquo; according to &ldquo;In-Space Additive Manufacturing: A Review,&rdquo; published in ASME&rsquo;s Journal of Manufacturing Science and Engineering in February 2023. 
&nbsp; 
In-space manufacturing (ISM), of which in-space additive manufacturing (ISAM) is a part, is a promising solution, the study suggests, which would integrate repair and fabrication techniques into space missions, &ldquo;providing on-demand capabilities to adapt to unforeseen situations.&rdquo; 
&nbsp; 
The study provides a literature review of ISAM and its related technologies and summarizes numerous studies available on this subject, while also discussing ISAM and identifying knowledge gaps. 
&nbsp; 
Lead author Miguel Hoffmann, a doctoral student at the Wm Michael Barnes &lsquo;64 Department of Industrial and Systems Engineering at Texas A &amp; M University, and principal investigator Alaa Elwany, associate professor and ASME Foundation Swanson Fellow, College of Engineering Eugene Webb Faculty Fellow, and director of the Texas A&amp;M Metal Additive Manufacturing Research Laboratory (AMTex), recently shared some additional insights on ISAM and what may lie ahead.

Use of additive manufacturing (AM) has exploded since its conception over 40 years ago. With more and more eyes looking skyward, from space tourism to NASA&rsquo;s return to the moon, the potential AM holds for use in orbit and beyond is notable.

Manufacturing Among the Stars

Mouthpieces Measure Movement with Precision

Stock car racing fans like to listen to &ldquo;mic&rsquo;d up&rdquo; drivers. But how about when NASCAR drivers sport custom-made mouthpieces to pick up more than action reactions? 
&nbsp; 
To collect real-time data on exposure to acceleration and vibrations, about half of all NASCAR drivers &ldquo;put instrumented, custom-fit mouthpieces inside their mouths,&rdquo; explained Joel Stitzel, a professor of biomedical engineering at the Wake Forest University School of Medicine in Winston-Salem, N.C. 
&nbsp; 
This helps researchers collect kinematics of drivers&rsquo; experience when performing practice laps or on race day. The results were released in the paper, &ldquo;Pilot Collection and Evaluation of Head Kinematics in Stock Car Racing,&rdquo; published in the March 2023 issue of Journal of Biomechanical Engineering. 
&nbsp; 
NASCAR has put a lot of effort into addressing driver safety&mdash;especially mitigating injury because of severe crashes. Head and neck restraints have reduced the incidence of severe brain injury, for example. 
&nbsp; 
But while crash safety and reduced numbers of concussions in sport grabs all the headlines, the need to understand the effects of regular and expected environmental exposure to subconcussive head impacts are also a concern. 
&nbsp; 
Moreover, while we may have an abundance of data on the protective equipment that comes into play during a high-speed crash scenario, less is known about what typical high-speed laps during practice and on race day expose drivers to. 
&nbsp; 
To better understand driver exposure and to inform future potential equipment or racing policy, in the past NASCAR and other sports collected data using sensors on helmets and other head gear, skin patches, or even from instruments worn in the ears. But the current strategy has proven to work well in this group to collect accurate and precise information about head kinematics. 
&nbsp; 
Because collecting accurate head kinematics is a vital step in assessing driver safety systems and better understanding exposure to injury risk and environmental factors, &ldquo;The goal of this work is to collect more accurate on-track driver head kinematics using instrumented mouthpieces and get a better understanding of environmental exposure to accelerations and vibrations during real-life, real-time race day and during practice laps,&rdquo; explained Stitzel in the paper. Research found that a custom instrumented mouthpiece is an excellent method for collecting accurate head acceleration data. 
&nbsp; 
<img src="~/wwwasmeorg/media/Magazines/RDPulse/Summer-2023/Mouthpieces-Measure-Movement-with-Precision_1.jpg" style="height:732px;width:750px;" />
Researchers at the Wake Forest University School of Medicine collected data from NASCAR drivers to monitor potentially brain-damaging accelerations.

Image credit: Wake Forest University School of Medicine
&nbsp; Six Drivers 
&nbsp; 
The ongoing study began using 3D dental scans for six stock car drivers. The team took the detailed scans of the top and bottom of drivers&rsquo; mouths to make each of them custom, tight-fitting mouthpieces. Approved by the Wake Forest University School of Medicine Institutional Review Board, the retainer-style devices contained motion-sensing instrumentation and partially covered the palate for direct measurement of skull movements. 
&nbsp; 
The mouthpiece sensors contained a tri-axial accelerometer and an angular rate sensor, and &ldquo;collected data both in interval mode during practice and impact mode during races,&rdquo; Stitzel explained. A member of the research team configured and deployed each mouthpiece device at each of four tracks and used a custom-built Android app. 
&nbsp; 
Researchers collected data at a total of nine on-track events: three organizational testing environments, three prerace practices, and three races. 
&nbsp; 
Moreover, at each data collection event, research staff recorded video to identify driver location on the track. This, along with quasi-continuous data collection with the mouthpiece enabled extraction and segmentation of complete laps of kinematic data for analysis. 
&nbsp; 
The final study examined data from a total of 42 complete laps from the NASCAR drivers. 
&nbsp; 
<img src="~/wwwasmeorg/media/Magazines/RDPulse/Summer-2023/Mouthpieces-Measure-Movement-with-Precision_2.jpg" style="height:500px;width:750px;" />
The data set included measurements taken during actual NASCAR races.

Image credit: Getty Images
&nbsp; 
Other Drivers 
&nbsp; 
This NASCAR-funded study has established the feasibility of using an instrumented mouthpiece to measure head movement with the hope of wider acceptance of the device within the larger population of drivers. 
&nbsp; 
This will allow the sport to better monitor head motion and when the movement exceeds certain thresholds, the mouthpiece records those moments, allowing for analyses and future safety improvements, explained John Patalak, vice president of safety engineering at NASCAR in Concord, N.C. 
&nbsp; 
&ldquo;Back in 2002 we put incident data recorders in the cars and that allowed us to do much better research and made us smarter,&rdquo; he said. Fast forward to the technology in the mouthpieces, &ldquo;it&rsquo;s a remarkably similar approach. We are measuring the kinematics of the driver during a crash. And that&#39;s very informative on our human body modeling efforts and our crash reconstructions. It&#39;s the same process. We can compare the data we&#39;re getting out of the live human drivers in real crashes with what the crash test dummy&#39;s instrumentation is telling us.&rdquo; 
&nbsp; 
This way NASCAR can improve its test processes, Patalak said, &ldquo;and how we evaluate safety equipment. We&rsquo;ve already taken data from mouthpiece sensors where drivers have come back and said, &lsquo;that was a hard hit where that&#39;s uncomfortable.&rsquo; And we&#39;ve taken those specific cases and&mdash;taking deep dives with the mouthpiece sensor data&mdash;to understand what types of movement they had experienced. And then we use that to recreate simpler tests, such as drop or sled testing. This way, we use that data as a basis for the speeds or the angles that we&#39;re running and where to make improvements. And we can make those improvements&mdash;better solutions&mdash;faster and with more confidence.&rdquo; 
&nbsp; 
Stitzel added, &ldquo;There are other sports where head kinematics need to be studied,&rdquo; such as soccer and gymnastics. Stitzel and Jillian Urban, an assistant professor of biomedical engineering at Wake Forest, have a patent pending on the mouthpiece instrumentation. 
&nbsp; 
Cathy Cecere is membership content program manager.

NASCAR drivers help Wake Forest researchers collect better data to measure drivers&#39; exposure to acceleration and vibration.

Stock car racing fans like to listen to &ldquo;mic&rsquo;d up&rdquo; drivers. But how about when NASCAR drivers sport custom-made mouthpieces to pick up more than action reactions? 
&nbsp; 
To collect real-time data on exposure to acceleration and vibrations, about half of all NASCAR drivers &ldquo;put instrumented, custom-fit mouthpieces inside their mouths,&rdquo; explained Joel Stitzel, a professor of biomedical engineering at the Wake Forest University School of Medicine in Winston-Salem, N.C. 
&nbsp; 
This helps researchers collect kinematics of drivers&rsquo; experience when performing practice laps or on race day. The results were released in the paper, &ldquo;Pilot Collection and Evaluation of Head Kinematics in Stock Car Racing,&rdquo; published in the March 2023 issue of Journal of Biomechanical Engineering.

NASCAR drivers help Wake Forest researchers collect better data to measure drivers&#39; exposure to acceleration and vibration.

July-September 2023

July-September 2024

October-December 2023

Air Force engineers 3D print turbine blades suitable for a drone engine.

Engineers are always trying to squeeze more power out of engines, and those in the military have added incentive. Military researchers looking to increase the power and thrust of a commercial compact jet engine turned to ceramics to meet the increased turbine inlet temperature that prevented them from using metals. Using finite element analysis and 3D printing, they showed that a turbine rotor made of silicon nitride could handle the higher temperatures and still provide increased power and thrust. 
 
&ldquo;We wanted to take something that was a small-scale engine that was already fairly power-dense to begin with and try to make it more power dense,&rdquo; said U.S. Air Force Lt. Col. Brian Bohan. &ldquo;There&rsquo;s a big gap in the commercial sector for this scale. We were trying to come up with ways to make an engine as powerful as some of the more expensive military engines, but at a more cost-effective price point.&rdquo;

Ceramic Boost for Small Jet Engines

To the annoyance of parents everywhere, children love playing with tape measures. They will lock the extended tape in place and notice how a slight curve keeps the metal strip rigid. Then they will release the lock and delight in how a spring retracts the tape with a satisfying thwack. 
 
Roboticists at the University of California, Los Angeles have been playing with tape measures, too. They have discovered that the rigid but bendy tape can be used as a new type of limb that acts something like a spider monkey&rsquo;s arm or an octopus&rsquo;s tentacle.

A new type of robotic arm takes its inspiration from the toolbox favorite.

Made to Measure

Scarlett Miller of Penn State discusses how engineering teams can build psychological safety in their members.

Members of teams with high levels of psychological safety feel free to express ideas and opinions. This feeling of safety promotes creativity and innovation. However, little evidence exists that shows how best to facilitate or build psychological safety within teams, especially in an educational context. Scarlett Miller, professor of engineering design and industrial engineering and director of the Center for Research in Design and Innovation at The Pennsylvania State University, recently led a team of researchers that published a study on this topic in the ASME Journal of Mechanical Design. She discusses the impact of interventions aimed at improving psychological safety in engineering design student teams.

Comfortable Enough to Innovate

Frigid temperatures can be lethal. New research sets a baseline for manufacturers developing insulated fabrics.

Extremely cold, sub-zero weather conditions can kill, even after only a short time. Poorly insulated clothing can result in life-threatening respiratory and cardiovascular problems, as well as frostbite and hypothermia. 
 
People survive longer in severe cold if they wear clothing and outerwear that are specially designed for cold-weather conditions. Knowing the amount of a time a person can survive for a set of environmental conditions is critical for developing new fabrics and clothing that extend survival time. 
 
To improve the design of advanced, cold-weather fabrics, researchers at the Department of Mechanical Engineering at the Indian Institute of Technology in New Delhi undertook a series of experiments to evaluate how three key factors&mdash;ambient temperature, fabric insulation, and metabolic heat (heat generated by a person as a function of the physical work performed)&mdash;impact survival time. Their research is described in a paper published by the Journal of Heat and Mass Transfer in July 2023.

Surviving the Cold

January-March 2024

Digital twin technology (DT) has been successfully deployed in fields as varied as aviation, manufacturing, and oil and gas. But civil engineering, especially for field-related applications, has not been a venue for DT, in part because it relies on a variety of external technologies and approaches that were developed for other engineering fields. The most frequent and consistent use of DT in civil engineering projects is in the operations and maintenance phase, whereas building information modeling (BIM) is pervasively utilized in the first phase of planning/design.&nbsp; 
 
To better understand how DT can be more uniformly applied in civil engineering, a research team led by Ruda Zhang, assistant professor of civil and environmental engineering at the University of Houston, conducted an in-depth literature review to develop a phase-based approach for using DT in the architecture, engineering, and construction (AEC) industry. The team also established a five-level rating system for defining the complexity and depth of the DT being used within these phases.&nbsp; 
 
&ldquo;Our systematic literature review studied the conventional techniques employed at each civil engineering phase,&rdquo; Zhang said. &ldquo;We then identified enabling technologies such as computer vision for extended sensing and the Internet of Things for reliable integration. Our goal is to show how DT is an important tool across the entire lifecycle of civil engineering projects and hopefully nudge researchers to think more holistically in their quest to integrate DT in civil engineering applications.&rdquo; &nbsp; 
 
Taiwo A. Adebiyi and Nafeezat A. Ajenifuja, both at the University of Houston, authored the paper with Zhang. The study, &ldquo;Digital Twins and Civil Engineering: Reorienting Adoption Strategies,&rdquo; appeared in the Journal of Computing and Information Science in Engineering in October 2024. &nbsp; 
 
&nbsp;
<h3>Three phases&nbsp;</h3>
 
One reason for the slow pace of DT adoption in civil engineering is the profession&rsquo;s resistance to change and the complexity of its projects. Every civil engineering project must go through three distinct and sequential phases: planning/design, construction, and operations and maintenance. Each of these phases utilizes AI in different ways, making it difficult to integrated the flow of DT across phases. The team researched how each phase uses DT and explored the different concepts/frameworks for phase-based DT applications.&nbsp;
<h4> 
Planning/Design Phase: Five Levels of BIM Growth&nbsp;</h4>
 
The integration of DT with BIM systems has been transformative for planning and design. The long-established practice of BIM has gradually evolved into a powerful digital tool. &nbsp; 
 
&ldquo;BIM has evolved from its inherent static configuration to an integrated dynamic powerhouse as an enabler for DT development in the built environment,&rdquo; Zhang said. BIM has grown from a rudimentary virtual reality &nbsp; program to include simulation, sensor technologies, and &nbsp;artificial intelligence (AI), all of which enable an advanced DT in the built environment.&nbsp;
<h4> 
Construction: Sensing, Internet of Things &nbsp;</h4>
 
How DT in deployed in the construction phase depends the other digital technologies being used, including sensing and the Internet of Things. &nbsp; 
 
&ldquo;Sensing technologies paved the way for real-time construction monitoring, enabling improved productivity, hazard identification, construction waste management, and clash detection,&rdquo; Zhang said. &ldquo;Laser scanners, RGB cameras, and depth cameras are used for mapping sensors; however, laser scanners are limited by the lack of color information&mdash;hence their combination with digital cameras to obtain colorized 3D point clouds.&rdquo;&nbsp;
<h4> 
Operations and Maintenance: Structural Health &nbsp;</h4>
 
Structural health monitoring (SHM) is an important application that relies on advanced DT technologies. SHM is segmented into two categories: diagnosis and prognosis. Most of the DT work done in this phase is diagnostic (damage detection, localization, and evaluation) with fewer advances in the prognosis category (for example, residual life prediction). Nonetheless, &ldquo;the advent of several miniaturized or sensor-based SHM systems directly attached to modern structures has paved the way for real-time monitoring of the structures via model updating and parameter estimations, otherwise known as system identification,&rdquo; Zhang said.&nbsp; 
 
When these and other DT tools are in place, the prognosis of aspect of SHM will become more attainable, &ldquo;including prediction, learning, management, optimization, and other context-specific functionalities&mdash;all of which are encompassed in a virtual duplicate of a physical infrastructure tagged DT,&rdquo; Zhang added.&nbsp; 
 
&nbsp;
<h3>A competitive tool&nbsp;</h3>
 
Zhang&rsquo;s research shows how BIM, sensing, and IoT are essential technologies/processes for developing highly sensitive digital twin technology for civil engineering applications. DT capabilities include data acquisition and processing through sensing technologies, data processing such as feature extraction via machine-learning methods, and data interpretation from extracted features or raw data using computer vision.&nbsp; 
 
Two other functions needed for effective DT development are uncertainty quantification and model updating. &nbsp; 
 
&ldquo;Model updating is a must for an accurate depiction of the digital states of the corresponding physical states of an asset,&rdquo; Zhang said. &ldquo;However, the need for continuous model updates can be computationally expensive due to the repetitive need for evaluations.&rdquo;&nbsp; 
 
More research is needed to determine the most efficient approach for model updates for the DT development of structural systems. For both uncertainty quantification and model updates, randomization of parameters for probabilistic evaluations is critical.&nbsp; 
 
If DT can be as advanced in civil engineering as it is in aviation and manufacturing, especially for mission planning optimization, &ldquo;it will become a competitive tool for sustainable and resilient civil engineering amidst the mounting environmental and social challenges in the AEC profession,&rdquo; Zhang concluded.&nbsp; 
 
Mark Crawford is a technology writer in Corrales, N.M.&nbsp;

The technology has uses beyond the aviation and manufacturing sectors. A new study found all three phases of civil engineering projects&mdash;planning/design, construction, and operation and maintenance&mdash;can find value in digital twins.

Digital twin technology (DT) has been successfully deployed in fields as varied as aviation, manufacturing, and oil and gas. But civil engineering, especially for field-related applications, has not been a venue for DT, in part because it relies on a variety of external technologies and approaches that were developed for other engineering fields. The most frequent and consistent use of DT in civil engineering projects is in the operations and maintenance phase, whereas building information modeling (BIM) is pervasively utilized in the first phase of planning/design.

Digital Twins Can Support Civil Engineering Projects

Gears are key components in automotive transmissions. Electrification of automotive powertrains over the coming years will pressure gear manufacturers to increase gear production. Any improvements that can maximize efficiency in the gear production chain will be in high demand for keeping up with market growth and reducing production costs. &nbsp; 
 
One way to do this is by improving the gear-grinding process. Grinding is important because it eliminates surface flaws, maximizes load capacity, and minimizes running noise. However, standard grinding of high-performance gears is a &ldquo;wet&rdquo; process&rdquo; that is time-consuming and requires multiple steps. Wet grinding typically uses a large amount of lubricant. Energy consumption for lubrification and cooling represents almost two-thirds of the total energy consumption of a typical grinding machining center&mdash;a cost that gear manufacturers would love to eliminate.&nbsp; 
 
To make dry grinding (no lubricants) more viable and cost-effective, a research team led by Erica Liverani, a senior assistant professor in the Department of Industrial Engineering at the University of Bologna in Italy, compared the high-performance gears made with conventional wet grinding with two other processes: superfinishing and dry grinding. By adjusting a variety of parameters, Liverani&rsquo;s team developed a dry grinding system that outperformed the other two methods. &nbsp; 
 
&ldquo;This shows that the complete elimination of lubricant in gear production is possible, leading to a more sustainable process without compromising gear performance,&rdquo; she said.&nbsp; 
 
Liverani and six coauthors published a paper on the topic, &ldquo;Dry Grinding: A More Sustainable Manufacturing Process for the Production of Automotive Gears,&rdquo; in the October 2024 issue of the Journal of Manufacturing Science and Engineering.&nbsp; 
 
&nbsp;
<h3>Ready, set&mdash;grind &nbsp;</h3>
 
The material and manufacturing processes that were used prior to grinding were the same in all cases, followed by grinding performed by the same manufacturer. &ldquo;The dimensional accuracy, roughness, microstructure, residual stress state, and wear resistance of gear flanks were then analyzed to compare the overall performance of each grinding process,&rdquo; Liverani said.&nbsp; 
 
Three grinding processes were selected based on current manufacturing standards and new requirements for carbon neutrality: &nbsp; 
 
Wet grinding (WG) served as a benchmark&nbsp; 
 
Dry hard finishing (DHG) performed without the use of lubricants &nbsp; 
 
Superfinishing (SF), a wet process that increases micro-pitting &nbsp; 
 
After grinding, all gears were analyzed with an optical microscope and scanning electron microscope for microstructure evaluation, an optical profiler for the acquisition of the surface topography and roughness, a Klingelnberg measuring system for evaluation of geometric errors, and an X-ray diffraction analysis for residual stress measurement. Finally, wear tests were performed to evaluate the influence of grinding on gear durability.&nbsp; 
 
<img alt="" src="~/getmedia/134c0c26-16b9-4bec-a00a-7d00d2961a99/gear-grinding-1.jpg" />
<div style="text-align: center;">Microscope images of gear teeth ground through different methods: a) wet grinding, b) and c) dry grinding, and d) and e) super finishing. Scuffing and micro-pitting are highlighted with white and black arrows, respectively. Image: Alessandro Fortunato, et al. in the Journal of Manufacturing Science and Engineering.</div>
&nbsp;

<h3> 
Cycle parameters&nbsp;</h3>
 
In terms of dimensional accuracy, roughness, and microstructure, &ldquo;the goal was to &nbsp;identify the best combination of parameters for achieving the best level of surface integrity,&rdquo; Liverani said. &ldquo;The grinding cycle parameters and grinding wheel specifications were changed depending on the grinding process being used.&rdquo;&nbsp; 
 
The results show that dry grinding can produce gears with acceptable geometric accuracy, no microstructure defects, and greater wear resistance than gears finished with conventional wet grinding or superfinishing. Findings include:&nbsp;
<ul>
	<li>No significant variations were found in the geometric accuracy of gears due to the grinding processes over the tested parameter range.</li>
	<li>Wet grinding and superfinishing achieved lower roughness, which could be detrimental for wear resistance.</li>
	<li>No significant variations were found in the microstructures of gears due to the grinding processes.</li>
	<li>Correct selection of process parameters allowed ground surfaces to be obtained without burns or a white layer.</li>
	<li>Dry-ground gears show slight tensile residual stresses in the flank surface, but a higher hardness was measured below the same surface with respect to wet grinding conditions.&nbsp;</li>
</ul>
&nbsp; 
<img alt="" src="~/getmedia/1d2a62f4-fe9c-447b-85fe-9a9a2d844c39/gear-grinding-2.jpg" />
<div style="text-align: center;">A schematic and photos of the experimental setup (a and b) and images of the gears ground in the experiment (c and d). Images: Alessandro Fortunato, et al. in the Journal of Manufacturing Science and Engineering.</div>

<h3 style="text-align: center;">&nbsp;</h3>

<h3> 
Stronger wear resistance</h3>
 
The flank profile of gears subject to dry grinding shows slight tensile values as a result of a high thermal gradient, which also causes microstructural defects if grinding parameters are not optimized. &nbsp; 
 
&ldquo;Nonetheless, in the tested conditions of this study, high hardness and beneficial topography assume a higher weight with respect to residual stresses, and wear tests revealed that dry ground gears have the longest durability,&rdquo; Liverani said. &ldquo;Based on these results, dry grinding could be an alternative to conventional wet grinding that satisfies the mechanical and geometric requirements of car manufacturers, while improving wear resistance, reducing waste, and increasing the sustainability of gear production in the strategic automotive market.&rdquo;&nbsp; 
 
Perhaps the greatest discovery was that the wear resistance of gears finished with dry grinding was considerably greater than that of gears finished with wet grinding or superfinishing. &ldquo;This is a fundamental advantage for electric vehicles, where noise must be minimized,&rdquo; Liverani said. &ldquo;The elimination of lubricant makes this solution more sustainable, improving wear resistance without compromising geometric accuracy.&rdquo;&nbsp; 
 
Mark Crawford is a technology writer in Corrales, N.M.

Researchers at the University of Bologna in Italy have developed a method of dry grinding for automotive gears&mdash;without using oils and other lubricants.

Gears are key components in automotive transmissions. Electrification of automotive powertrains over the coming years will pressure gear manufacturers to increase gear production. Any improvements that can maximize efficiency in the gear production chain will be in high demand for keeping up with market growth and reducing production costs. &nbsp; 
 
One way to do this is by improving the gear-grinding process. Grinding is important because it eliminates surface flaws, maximizes load capacity, and minimizes running noise. However, standard grinding of high-performance gears is a &ldquo;wet&rdquo; process&rdquo; that is time-consuming and requires multiple steps. Wet grinding typically uses a large amount of lubricant. Energy consumption for lubrification and cooling represents almost two-thirds of the total energy consumption of a typical grinding machining center&mdash;a cost that gear manufacturers would love to eliminate.

A More Sustainable Way to Make Automotive Gears

The first large-scale implementation of an air-conditioning system was at the Sackett-Wilhelms Lithographing &amp; Publishing Company in Brooklyn in 1902, which used the then-new invention to limit the amount of moisture absorbed by paper. Today, most factories are climate controlled. But not all factory owners optimize their heating, ventilation, and air conditioning (HVAC) systems for energy efficiency. &nbsp; 
 
Forooza Samadi, assistant director of the Alabama Industrial Training and Assessment Center and assistant professor of mechanical engineering at the University of Alabama in Tuscaloosa, recently studied ways factories could cut costs and carbon emissions. She was coauthor on the paper, &ldquo;Strategic Evaluation of Sustainable Practices for HVAC Systems in Small- and Medium-Sized U.S. Manufacturers,&rdquo; published in the ASME Journal of Engineering for Sustainable Buildings and Cities in August 2024. Here, she described some of her findings.

Manufacturers rely on heating, cooling, and ventilation systems to provide optimal environments for their equipment&mdash;and workers. University of Alabama researcher Forooza Samadi describes ways companies can optimize these systems.

Q&A: Improving Efficiency in HVAC Systems

<div class="infogram-embed" data-id="c5427764-aac3-494d-bbf4-bdc77c799903" data-title="Robot Throwing" data-type="interactive">&nbsp;</div>
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It&rsquo;s not all about power&mdash;a robotic arm needs the right technique and architecture to hurl an object efficiently.

April-June 2023

In This Issue

article

Cool Water Boosts Solar Efficiency

article

Printing Better, Cheaper Heat Exchangers

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Q & A

Using Smart Trains to Find Defective Rails

infographic

Better Grip for Laparoscopy

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