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Nuclear rockets could travel to Mars in half the time − but designing the reactors that would power them isn’t easy

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theconversation.com – Dan Kotlyar, Associate Professor of Nuclear and Radiological Engineering, Georgia Institute of Technology – 2024-10-04 07:23:18

Nuclear-powered rockets could one day enable faster travel.
NASA

Dan Kotlyar, Georgia Institute of Technology

NASA plans to send crewed missions to Mars over the next decade – but the 140 million-mile (225 million-kilometer) journey to the red planet could take several months to years round trip.

This relatively long transit time is a result of the use of traditional chemical rocket fuel. An alternative technology to the chemically propelled rockets the agency develops now is called nuclear thermal propulsion, which uses nuclear fission and could one day power a rocket that makes the in just half the time.

Nuclear fission involves harvesting the incredible amount of energy released when an atom is split by a neutron. This reaction is known as a fission reaction. Fission technology is well established in power generation and nuclear-powered submarines, and its application to or power a rocket could one day give NASA a faster, more powerful alternative to chemically driven rockets.

NASA and the Defense Advanced Research Projects Agency are jointly developing NTP technology. They plan to deploy and demonstrate the capabilities of a prototype system in space in 2027 – potentially making it one of the first of its kind to be built and operated by the U.S.

Nuclear thermal propulsion could also one day power maneuverable space platforms that would protect American satellites in and beyond Earth’s orbit. But the technology is still in .

I am an associate professor of nuclear engineering at the Georgia Institute of Technology whose research group builds models and simulations to improve and optimize designs for nuclear thermal propulsion . My hope and passion is to assist in designing the nuclear thermal propulsion engine that will take a crewed mission to Mars.

Nuclear versus chemical propulsion

Conventional chemical propulsion systems use a chemical reaction involving a light propellant, such as hydrogen, and an oxidizer. When mixed together, these two ignite, which results in propellant exiting the nozzle very quickly to propel the rocket.

A diagram showing a nuclear thermal propulsion system, with a chamber for hydrogen connected to several pumps, a reactor chamber and a nozzle that the propellant is ejected from.
Scientists and engineers are working on nuclear thermal propulsion systems that would take hydrogen propellant, pump it into a nuclear reactor to generate energy and expel propellant out the nozzle to lift the rocket.
NASA Glenn Research Center

These systems do not require any sort of ignition system, so they’re reliable. But these rockets must carry oxygen with them into space, which can weigh them down. Unlike chemical propulsion systems, nuclear thermal propulsion systems rely on nuclear fission reactions to heat the propellant that is then expelled from the nozzle to create the driving force or thrust.

In many fission reactions, researchers send a neutron toward a lighter isotope of uranium, uranium-235. The uranium absorbs the neutron, creating uranium-236. The uranium-236 then splits into two fragments – the fission products – and the reaction emits some assorted particles.

Fission reactions create lots of heat energy.

More than 400 nuclear power reactors in operation around the world currently use nuclear fission technology. The majority of these nuclear power reactors in operation are light water reactors. These fission reactors use to slow down the neutrons and to absorb and transfer heat. The water can create steam directly in the core or in a steam generator, which drives a turbine to produce electricity.

Nuclear thermal propulsion systems operate in a similar way, but they use a different nuclear fuel that has more uranium-235. They also operate at a much higher temperature, which makes them extremely powerful and compact. Nuclear thermal propulsion systems have about 10 times more power density than a traditional light water reactor.

Nuclear propulsion could have a leg up on chemical propulsion for a few reasons.

Nuclear propulsion would expel propellant from the engine’s nozzle very quickly, generating high thrust. This high thrust allows the rocket to accelerate faster.

These systems also have a high specific impulse. Specific impulse measures how efficiently the propellant is used to generate thrust. Nuclear thermal propulsion systems have roughly twice the specific impulse of chemical rockets, which means they could cut the travel time by a factor of 2.

Nuclear thermal propulsion history

For decades, the U.S. has funded the development of nuclear thermal propulsion technology. Between 1955 and 1973, programs at NASA, General Electric and Argonne National Laboratories produced and ground-tested 20 nuclear thermal propulsion engines.

But these pre-1973 designs relied on highly enriched uranium fuel. This fuel is no longer used because of its proliferation dangers, or dangers that have to do with the spread of nuclear material and technology.

The Global Threat Reduction Initiative, launched by the Department of Energy and National Nuclear Security Administration, aims to convert many of the research reactors employing highly enriched uranium fuel to high-assay, low-enriched uranium, or HALEU, fuel.

High-assay, low- enriched uranium fuel has less material capable of undergoing a fission reaction, with highly enriched uranium fuel. So, the rockets needs to have more HALEU fuel loaded on, which makes the engine heavier. To solve this issue, researchers are looking into special materials that would use fuel more efficiently in these reactors.

NASA and the DARPA’s Demonstration Rocket for Agile Cislunar Operations, or DRACO, program intends to use this high-assay, low-enriched uranium fuel in its nuclear thermal propulsion engine. The program plans to launch its rocket in 2027.

As part of the DRACO program, the aerospace company Lockheed Martin has partnered with BWX Technologies to develop the reactor and fuel designs.

The nuclear thermal propulsion engines in development by these groups will need to comply with specific performance and safety standards. They’ll need to have a core that can operate for the duration of the mission and perform the necessary maneuvers for a fast trip to Mars.

Ideally, the engine should be able to produce high specific impulse, while also satisfying the high thrust and low engine mass requirements.

Ongoing research

Before engineers can design an engine that satisfies all these standards, they need to start with models and simulations. These models researchers, such as those in my group, understand how the engine would handle starting up and shutting down. These are operations that require quick, massive temperature and pressure changes.

The nuclear thermal propulsion engine will differ from all existing fission power systems, so engineers will need to build software tools that work with this new engine.

My group designs and analyzes nuclear thermal propulsion reactors using models. We model these complex reactor systems to see how things such as temperature changes may affect the reactor and the rocket’s safety. But simulating these effects can take a lot of expensive computing power.

We’ve been working to develop new computational tools that model how these reactors act while they’re starting up and operated without using as much computing power.

My colleagues and I hope this research can one day help develop models that could autonomously control the rocket.The Conversation

Dan Kotlyar, Associate Professor of Nuclear and Radiological Engineering, Georgia Institute of Technology

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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The Conversation

Election anxiety doesn’t need to win − here are 3 science-backed strategies from a clinical psychologist to rein in the stress

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theconversation.com – Shannon Sauer-Zavala, Associate Professor of Psychology & Licensed Clinical Psychologist, University of Kentucky – 2024-11-01 15:46:00

The world won’t end if you stop scrolling.
georgeclerk/E+ via Getty Images

Shannon Sauer-Zavala, University of Kentucky

Uncertainty about the election getting to you? Is anxiety the dominant feature of your emotional landscape, maybe with a small sprinkling of impending doom?

You are not alone. A recent survey found 69% of American adults are seriously stressed about the 2024 presidential election.

It’s difficult not to be worked up about in ‘s polarized climate. Regardless of which side of the political aisle you sit on, you may find yourself glued to your browser or TV, gobbling up every tiny tidbit of news and feeling your stress levels skyrocket.

I’m a psychologist who develops and tests strategies for combating anxiety. As I constantly tell my stressed-out clients, when it comes to election news, there’s a fine line between being well informed and being oversaturated with information.

If you’re ready to short-circuit your stress spiral, here are three science-backed strategies for coping with anxiety in times of uncertainty.

Approach your emotions with mindfulness

Being mindful refers to the quality of awareness you bring to your experiences – specifically, nonjudgmental attention focused on what’s right now.

Mindfulness practices originated in Eastern spiritual traditions, Buddhism. Over the past several decades, mindfulness has gained popularity as a powerful tool for managing anxiety. For instance, meditation apps such as Headspace and Calm incorporate it. Even if meditation isn’t your thing, though, you can still apply nonjudgmental awareness, focused on the present, to election-related anxiety.

Be present. Anxiety can draw you into an uncomfortable spiral of “what-ifs” about the future. When you make a point to be present, you remind yourself what is actually happening right now, rather than letting hypothetical fears take over.

Although you may have serious concerns about the fate of the nation, those outcomes have not yet come to bear. As I tell my , “We’ll cross that bridge if we come to it. For now, focus on the step right in front of you.”

If you notice yourself getting carried away by of the future, you can pull yourself back to the present by bringing awareness to simple sensations – the feel of your feet on the floor, the rhythm of your breath, or the sounds around you – and remind yourself that you are safe in the current moment.

Pay nonjudgmental attention. Many people are hard on themselves for feeling strong emotions. This critical mindset might look like telling yourself that you’re overreacting, or that it’s weak to let others see that you’re upset. You might even view that uncomfortable feeling in the pit of your stomach as evidence that negative outcomes are right around the corner.

Making judgments about your emotions only serves to make you feel worse. In fact, researchers find that pushing away emotions or beating yourself up for having them leads to more frequent and stronger anxiety.

Instead, try giving yourself a break. Tell yourself, “This election is high stakes, so it makes sense I’m anxious.” Then, notice if your anxiety is driven by a fear about the future, and bring yourself back to the present.

older woman comforts a younger woman who is looking off into distance
Pull your thoughts back to the here and now.
supersizer/E+ via Getty Images

Get flexible with your thinking

Cognitive flexibility is the ability to shift away from rigid, all-or-nothing thinking about the future.

When people are anxious, they tend to focus on the worst-case scenario. For example, you might be telling yourself, “With this candidate in office, things will be terrible and I won’t be able to cope.”

In this scenario, I encourage my patients to move past that initial thought of how awful it will be and instead consider exactly how they will respond to the inauguration, the next day, week, month and so on.

Cognitive flexibility allows you to explore how you will cope, even in the face of a negative outcome, helping you feel a bit less out of control. If you’re experiencing a lot of anxiety about the election, try thinking through what you’d do if the undesirable candidate takes office – thoughts like “I’ll to causes that are important to me” and “I’ll attend protests.”

Choose your actions with intention

Another tool for managing your anxiety is to consider whether your behaviors are affecting how you feel.

Remember, for instance, the goal of 24-hour news networks is to increase ratings. It’s in their interest to keep you riveted to your screens by making it seem like important announcements are imminent. As a result, it may feel difficult to disconnect and take part in your usual self-care behavior.

Try telling yourself, “If something happens, someone will text me,” and go for a walk or, better yet, to bed. Keeping up with healthy habits can reduce your vulnerability to uncontrolled anxiety.

woman faces away from camera, wearing a 'VOTE' t shirt
It’s not on your shoulders to solve every single problem in the world.
AP Photo/John Hanna

Post-Election Day, you may continue to feel drawn to the news and motivated to show up – whether that means donating, volunteering or protesting – for a variety of causes you think will be affected by the election results. Many people describe feeling guilty if they say no or disengage, leading them to overcommit and wind up overwhelmed.

If this sounds like you, try reminding yourself that taking a break from politics to cook, engage with your or friends, get some work done or go to the gym does not mean you don’t care. In fact, keeping up with the activities that fuel you will give you the energy to contribute to important causes more meaningfully.The Conversation

Shannon Sauer-ZavalaUniversity of Kentucky

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How to overcome your device dependency and manage a successful digital detox

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theconversation.com – Kelley Cours Anderson, Assistant Professor of Marketing, College of Charleston – 2024-11-01 07:39:00

Getting outside – without your phone – is one way to disconnect.
We Are/DigitalVision via Getty Images

Kelley Cours Anderson, College of Charleston and Karen Anne Wallach, University of Alabama in Huntsville

in the digital world can be rewarding. It’s convenient to order groceries for pickup, share photographs or music, and keep in touch with and friends, no matter the distance. However, it can also be draining. The feeling of being constantly “on” and productive has driven people to reconsider their balance in the saturated digital world.

More than 70% of American adults are concerned about how technology affects their mental health and personal relationships. This worry is reinforced through that point to people’s unhealthy habits with social media and phones.

What to do? There is a fuzzy line between healthy and unhealthy digital consumption. Some folks feel the need to fully disconnect from the digital world to understand this boundary. The idea of digital detoxing is gaining popularity. This practice involves intentionally unplugging from digital technologies in the pursuit of balance and digital well-being. Nearly half of Americans report that they are making a conscious effort to regularly step away from their screens.

But is this attempt enough? It’s no surprise that 62% of Americans confess to feeling addicted to their devices and the internet. Despite people’s best efforts to unplug and strike a balance, research indicates that digital detoxes often fall short.

two men in a park grin as one tosses a bean bag
Getting outside, being with someone else and fun are all good approaches to disconnecting from the digital world.
kali9/E+ via Getty Images

Digital well-being is subjective. We research technology and consumer behavior. Our recent research studied the digital detox journey, where people take a much-needed break from digital consumption, aiming to uncover what supports or sabotages those seeking digital well-being. Our findings highlighted four key strategies to improve the outcome of this journey toward achieving a healthier digital balance: replacement practices, social bonds, mindfulness and digital well-being as a journey.

1. Finding replacement practices

We found that feelings of withdrawal during a digital detox are quite common. For many, reaching for their phones and scrolling has become such a ritual that they often don’t realize they are doing it. Many turn to their devices when bored or stressed, much like an adult pacifier. As a result, finding an alternative to distract your mind and occupy your hands can be crucial during a digital detox.

These replacement practices often involve hobbies or activities that result in play. As adults, people sometimes forget what it feels like to have fun. By separating fun from your task list and engaging in play for its own sake, you can significantly reduce stress levels and boost your digital well-being.

2. Shoring up social bonds

Humans are inherently social creatures. Indeed, tools such as email, text messages and social media offer ways to enhance social connections. This innate desire for connection, however, combined with people’s reliance on technology, can lead to feelings of FOMO – fear of missing out – and anxiety during a digital detox.

The average adult now spends 70% less time with friends than they did two decades ago. Digital devices offer connection, but pieces of the experience are missing, such as the joy of in-person contact and trust in others that can be difficult to get online. So while we’re a more connected society, relationships suffer and people are more lonely than ever.

Therefore, during a digital detox it is vital to fill your cup with community, whether through existing friendships or by creating new ones. We recommend engaging in a digital detox alongside others, because FOMO may rear its ugly head if your friend pulls out their phone during a night out.

Taking a short digital detox with the Offline Club.

3. Emphasizing mindfulness

In ‘s fast-paced , finding a moment to pause can feel nearly impossible. Many experience solitude deprivation, meaning people often don’t have moments to be alone with their own thoughts. Yet, the ability to just be can allow time for reflection, helping you consider what makes you happy and healthy. Finding moments where you can step away – to be still and silent – can a much-needed recharge.

With adults spending about 90% of their time indoors, breaking the routine and outside can offer a more holistic perspective on both personal and global well-being. In our study, yoga and meditation were common ways that detoxers found moments to become more aware of their own thoughts, which helped foster more intentional behaviors.

4. Viewing digital well-being as an ongoing journey

Ultimately, digital well-being is a journey. It is not a checklist that, once completed, means you are fulfilled.

Unfortunately, a single detox isn’t enough to cure digital imbalance. Instead, a successful detox often leaves people feeling introspective and curious. Our research participants shared that relapses are common, especially if they don’t set and monitor ongoing goals. Importantly, your needs change and evolve over time. In other words, what works now might not be what you need in the future.

Willpower just isn’t enough. We recommend identifying specific goals for yourself related to your own digital well-being. These aren’t productivity goals but goals to be unproductive. The aim is to unplug in more fulfilling ways. Whether planning a weekly game night with friends or taking a 10-minute walk without your phone, making time to unplug is worth it in the long run.

Researchers still have more to learn to help support digital wellness. We should remember, though, that individual differences play a crucial role in this equation, meaning that the journey to achieving digital harmony is uniquely personal. Thus, as people navigate their tech-saturated lives, it’s clear that finding the right balance is a complex, highly individualized .

The digital detox journey can be challenging, but many people discover it to be rewarding in the end. People are not machines, however, so recognizing your limits and finding ways to reconnect with yourself and others during a detox can significantly enhance your sense of humanity and digital well-being.The Conversation

Kelley Cours Anderson, Assistant Professor of Marketing, College of Charleston and Karen Anne Wallach, Assistant Professor of Marketing, University of Alabama in Huntsville

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‘Safe route’ or ‘sushi route’ − 2 strategies to turn yuck to yum and convince people to eat unusual foods

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theconversation.com – Alexandra Plakias, Associate Professor of Philosophy, Hamilton College – 2024-11-01 07:39:00

By the 1980s, many New Yorkers were all in on sushi, a food that seemed weird just decades before.
Allan Tannenbaum/Getty Images

Alexandra Plakias, Hamilton College

What will the diets of the future look like? The answer depends in part on what foods Westerners can be persuaded to eat.

These consumers are increasingly being told their diets need to change. Current eating habits are unsustainable, and the global demand for meat is growing.

Recent years have seen increased interest and investment in what are called alternative proteins – products that can replace typical meats with more sustainable alternatives. One option is cultivated, or cultured, meat and seafood: muscle tissue grown in labs in bioreactors, using animal stem cells. Another approach involves replacing standard meat with such options as insects or plant-based imitation meats. All of these products promise a more sustainable alternative to factory-farmed meat. The question is, will consumers accept them?

I’m a philosopher who studies food and disgust, and I’m interested in how people react to new foods such as lab-grown meat, bugs and other so-called alternative proteins. Disgust and food neophobia – a fear of new foods – are often cited as obstacles to adopting new, more sustainable food choices, but I believe that recent history offers a more complicated picture. Past shifts in food habits suggest there are two paths to the adoption of new foods: One relies on familiarity and safety, the other on novelty and excitement.

Disgust and the yuck factor

Disgust is a strong feeling of revulsion in response to objects perceived to be contaminating, polluting or unclean. Scientists believe that it evolved to protect human beings from invisible contaminants such as pathogens and parasites. Some causes of disgust are widely shared, such as feces or vomit. Others, including foods, are more culturally variable.

So it’s not surprising that self-reported willingness to eat insects varies across nationalities. Insects have been an important part of traditional diets of cultures around the world for thousands of years, the ancient Greeks.

Many articles about the possibility of introducing insects to Western or American diners have emphasized the challenges posed by neophobia and “the yuck factor.” People won’t accept these new foods, the thinking goes, because they’re too different or even downright disgusting.

If that’s right, then the best approach to win on the plate for new foods might be to try to make them seem similar to familiar menu items.

The safe route to food acceptance

Poster from 1940s with photo of soldier and civilians saluting with heading 'Sure – We'll 'Share the Meat''
During World War II, the worked to make it seem patriotic to not pig out on the usual meat.
U.S. National Archives/Flickr, CC BY

During World War II, the United States government wanted to redirect its limited meat supply to troops on the front lines. So it needed to convince home cooks to give up their steaks, chops and roasts in favor of what it called variety meats: kidneys, liver, tongue and so on.

To figure out how to shift consumer habits, a team of psychologists and anthropologists was charged with studying how food habits and preferences were formed – and how they could be changed.

The Committee on Food Habits recommended stressing these organ meats’ similarity to available, familiar, existing foods. This approach – call it the “safe route” – focuses on individual attitudes and choices. It tries to psychological and practical barriers to individual choice and counteracts beliefs or values that might dissuade people from adopting new foods.

As the name suggests, the safe route tries to downplay novelty, using familiar forms and tastes. For example, it would incorporate unfamiliar cuts of meats into meatloaf or meatballs or grind crickets into flour for cookies or protein bars.

The sushi route

But more recent history suggests something different: Foods such as sushi, offal and even lobster became desirable not despite but because of their novelty and difference.

Sushi’s arrival in the postwar U.S. coincided with the rise of consumer culture. Dining out was gaining traction as a leisure activity, and people were increasingly open to new experiences as a sign of status and sophistication. Rather than appealing to the housewife preparing comfort foods, sushi gained popularity by appealing to the desire for new and exciting experiences.

By 1966, The New York Times reported that New Yorkers were dining on “raw fish dishes, sushi and sashimi, with a gusto once reserved for corn flakes.” Now, of course, sushi is widely consumed, available even in grocery stores nationwide. In fact, the grocery chain Kroger sells more than 40 million pieces of sushi a year. Whereas the safe route suggests sneaking new foods into our diets, the sushi route suggests embracing their novelty and using that as a selling point.

Sushi is just one example of a food adopted via this route. After the turn of the millennium, a new generation of diners rediscovered offal as high-end restaurants and chefs offered “nose to tail” dining. Rather than positioning foods like tongue and pigs’ ears as familiar and comforting, a willingness to embrace the yuck factor became a sign of adventurousness, even masculinity. This framing is the exact opposite of the safe route recommended by the Committee on Food Habits.

Chef displaying a plate of fried bugs with guacamole
Mexico is one place that has a centuries-old tradition of eating some insects.
AP Photo/Dario Lopez-Mills

The future of alternative proteins

What lessons can be drawn from these examples? For dietary shifts to last, they should be framed positively. Persuading customers that variety meats were a necessary wartime substitution worked temporarily but ultimately led to the perception that they were subpar choices. If cultivated meat and insects are pitched as necessary sacrifices, any gains they make may be temporary at best.

Instead, producers could appeal to consumers’ desire for healthier, more sustainable and more exciting foods.

Cultivated meat may be “safe-ly” marketed as nuggets and burgers, but, in principle, the options are endless: Curious consumers could sample lab-grown whale or turtle meat guilt-, or even find out what woolly mammoth tasted like.

Ultimately, the chefs, consumers and entrepreneurs seeking to remake our food don’t need to choose just one route. While we can grind insects into protein powders, we can also look to chefs cooking traditional cuisines that use insects to broaden our culinary horizons.The Conversation

Alexandra Plakias, Associate Professor of Philosophy, Hamilton College

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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