How to clean your Android phone thoroughly: erase all trash safely

New year, new life, they say. And this also concerns the mobile: nothing like doing a thorough cleaning to leave it glowing in the face of 2020. Now, it is convenient to know the operation of the phone to perform the cleaning safely, if there can be no problems. And that we have proposed today: we will eliminate all the garbage so that your Android is as clean as if it were new again. Learn more about new devices at

We will proceed step by step to adapt the level of cleanliness to your needs. As we ascend the cleaning will be deeper; And, with it, there will also be certain side effects. So, before proceeding with the deletion, you should make a backup of your smartphone, including photos, messages, and contacts.

Our first recommendation is clear: do not install applications that promise to wipe out all the garbage on your phone. Much of these apps get the opposite effect: instead of wiping your phone will end up dirtying advertising, they will slow down and can even infect you with malware. Go very carefully.

Remove apps you don’t use

This point is basic: the first step of any cleaning must be to end the superfluous. That is all those applications that you installed “just in case” and that in the end are occupying unnecessary space on the phone. They can even consume data and battery even if you have never opened them.

Do not have contemplations: finish with everything you do not use. Apps that have become unused, games you tried one day and ended up staying on the phone, take out everything that has no direct utility for you. Your phone will thank you (and you too).

Goodbye to the WhatsApp gallery

After unused applications, the gallery left by WhatsApp and company messages is the element that accumulates the most trash of the entire phone. Because does that ton of photos with funny memes that send you from the three hundred groups in which you signed up really serve you? The same goes for videos: to the garbage container. And without going through recycling.

To delete the WhatsApp gallery you have to do the following:

  • Access the reel of the application (it is in a folder called the same as the messaging app, inside the gallery) and review the content in case there is something you want to save. It is always good to make sure.
  • Once you have saved what is important (if there is anything), do not have mercy and delete the folder. In case you can’t do it from the gallery, use a file manager.
  • To prevent WhatsApp from automatically downloading multimedia content to the gallery, preventing it from being filled again with “garbage”, you just have to go to its settings and enter Data and storage. Leave “No file” selected to download with mobile data, Wi-Fi and roaming. This will only save what you download manually.

Remember to make frequent cleaning of the folders in the gallery where the photos of the chats are stored: they tend to become huge.

Delete unwanted photos and videos

At the previous point, it’s time to take a look at the gallery to eliminate everything you don’t want to keep. Screenshots (it is a must-see folder), images that you only used to share promptly and videos that have lost all meaning: if you do not think they are really worth it, it is best to remove them from your mobile. Also, if you have a cloud backup of all the content you can also delete some photos and videos that interest you from the phone. Having a secure backup will free up a lot of mobile space.

Make sure that after deleting the photos and videos, they do not remain in the recycle bin: there are custom layers that do not directly delete the content just in case you would like to recover it (the quarantine is usually one month). Enter the settings of your gallery, access the recycle bin and completely eliminate what you do not want.

Clear cache yes or no?

Usually, the application cache is usually considered as system garbage, but this is not entirely true: thanks to that cache all apps can boot faster since they store content that they do not have to generate again. Now, not all apps behave correctly with the cache as there are real storage eaters. Google Chrome and Facebook are two good examples.

Our recommendation is that you do not delete cache unless the application has saved too many MB and you really need the space. Check the settings of the most controversial apps (Chrome, Facebook, Instagram or Twitter, for example) and, if spread, delete your cache: the option is in the storage settings.

This robot is capable of imitating the handwriting of any person

Just by looking at the target image of a word or sketch, the robot can reproduce each stroke as a continuous action thanks to an algorithm developed by Brown University scientists.

The algorithm thus makes it very difficult for us to distinguish whether the text was written by the robot or if it was written by a human.

Deep Learning

The algorithm makes use of deep learning networks that analyze images of handwritten words or sketches and can deduce the likely series of pencil strokes that created them. The algorithm was trained using a Japanese character set until it was able to reproduce the characters and strokes that created them with approximately 93% accuracy.

The algorithm ended up reproducing very different types of characters that I had never seen before: English letters and italics, for example. As the authors explain:

To illustrate how our system works in various robotic environments, we tested our model with two robots, Baxter and Movo. We applied our trained model directly to the actual robotic environment, creating a need to process the original target image to match the image format of our training data.

Using a global model that considers the image as a whole, the algorithm identifies a likely starting point for the first stroke. Once the stroke has begun, the algorithm zooms in, looking at the image pixel by pixel to determine where that stroke should go and how long it should last. When it reaches the end of the stroke, the algorithm calls back the global model to determine where the next stroke should begin, and then returns to the expanded model. And so on.

That’s how we’ve changed screens for over 70 years.

We often go too far as alarmists when a new technology appears. Now it’s up to the screens (mobile, tablet, basically), to which we assign all sorts of negative aspects: what if the blue light, if it hypnotizes us, if we spend too much time looking at them, and so on. These are questions that, one by one, will have to be investigated little by little, but which, ironically, do not differ much from the criticisms that were made of television and, even further back, of books. Yes, there was a time when books were criticized in the same way that the Internet is now criticized.

We must be alert, without being doomsayers, then, because besides, the screens are changing at great speed. In short, maybe they won’t be screens in the classic sense. In only 70 years, in fact, screens have changed in this way.

70 years

1959: Ben-Hur, the most expensive Hollywood film with the most expensive campaign in history, was released. It became the blockbuster film, just after Gone with the Wind. At this time, the movie industry was the third in the United States, after grocery stores and cars.

1965: More than 90 percent of households now have television. People spend more than five hours in front of it. They are less likely to go to the movies. The number of seats bought by an adult fell from about 25 a year in 1950 to 4 in 2015.

Beginning of the 21st century: People start subscribing to television, paying for personalized content. Time Warner and Disney start earning more money from cable channels than from their film divisions.

This is the first spacecraft to raise its orbit around the Earth using sunlight.

Weighing just 5 kilograms, this cubeSat (small, standardized spacecraft that have made space flight more affordable), the size of a loaf of bread called LightSail 2 from the Planetary Society, is set to become the first spacecraft to raise its orbit around the Earth using sunlight: it will take off on June 22 aboard a Falcon Heavy Space X rocket from Kennedy Space Center in Florida.

LightSail 2, arrived in space, will deploy a solar sail and attempt to raise its orbit with the gentle thrust of the solar photons. While light has no mass, it has an impulse that can be transferred to other objects. A solar candle takes advantage of this impulse for propulsion.

LightSail 2
The sails, which have a combined area of 32 square metres, will turn towards the Sun during half of each orbit, which will give the spacecraft a small push which in microgravity conditions will be more than sufficient. For about a month after the deployment of the sail, this continuous impulse should increase the orbit of LightSail 2 by a measurable amount.

LightSail 2 will travel into space aboard the Department of Defense Space Test Program (STP-2) mission scheduled for launch on June 22, 2019. This is an unprecedented milestone, according to Planetary Society CEO Bill Nye:

Forty years ago, my professor Carl Sagan shared his dream of using a solar-sailed spacecraft to explore the cosmos. The Planetary Society is realizing the dream. Thousands of people from all over the world came together and supported this mission. We couldn’t have done it without them. Carl Sagan, and his colleagues Bruce Murray and Louis Friedman, created our organization to empower people everywhere to advance space science and exploration.

Science and data say one thing and airlines another: this would be the perfect boarding on an aeroplane.

We are in the age of data, but those who handle it don’t always seem to want to heed what that data reveals. It happens, for example, with boarding the plane before take-off, a tedious process that usually condemns us to long waits, as well as to some tension and stress.

All this could be minimised if airlines paid more attention to the data. Some do, but science is very clear that the boarding method often used is not optimal. Hopefully those who manage that process will read us.

Shipping Methods: There Are Them, There Are Them

A Boeing study long ago revealed that the boarding of an airplane was 50% slower in 1998 than in 1970. We will have made progress on many things, but the rate of passengers entering the plane by the minute has worsened dramatically in recent years.

We already mentioned in the past that there are several shipping methods that have been used over the years. The best known and most popular are the following:

From back to front: if the shipment is from the door closest to the nose, it is normal to find a process that tries to go from the last rows, the closest to the tail, to the first. The aim is to try to avoid crowds in the first rows with people trying to access the last ones.
From outside to inside (“Wilma method”): first the windows, then the intermediate seats and finally the aisle seats.
By seat numbering: a combination of the two above that takes both factors into account.
Random: it does not take into account any of these possible boarding priority parameters and instead chooses rows and seats entirely at random.

To evaluate the differences in these different boarding modes there are studies like Menkes van den Briel’s, the problem is that although in the first few minutes improvements can be noticed between them, they all converge to a very similar end time.

Much more detailed is the fantastic study (PDF) of Jason Steffen, an astrophysicist from the Fermi National Laboratory in Illinois who even devised his own boarding method through his results.

The so-called “Steffen method” organizes boarding in alternate rows with the window seats first moving backwards and forwards. Thus, 12A would be followed by 10A, 8A, etc., and then we would return to 9A, 7A, 5A, and so on, and then fill the middle seats and the aisle seats below.

That theory was singular, but would it really be fulfilled? That’s what a television producer named Jon Hotchkiss proposed to Steffen. To get the idea off the ground, he created a kind of model of a Boeing 757 and had the help of 72 volunteers who acted as virtual passengers.

The result, as shown in the table above, was surprising: the Wilma method was very good, but his method confirmed his theory and was even better at making a shipment in the shortest possible time.

These experiments did not stop there: the popular TV series “Myth Hunters” studied precisely this question in episode 222.

Those responsible for the program simulated the boarding of an airplane with 173 passengers and even took into account realistic situations and indicated to 5% of the passengers that they were “problematic”: to sit in the seat that was not, to travel with children or to lose time by putting their luggage in very quietly and obstructing the passage of other passengers.

In this process there were several curious results, mainly because the boarding time was evaluated as well as the satisfaction of the passengers who boarded. The quickest (except priority, that each passenger choose their place) was the one that generated the worst satisfaction.

The most complete was probably the singular inverse pyramid (priotaries in the first place, after which a “cascade” of zones was used that was dispersed from the rear window seats), above Wilma and Wilma with blocks: it took a little longer than these methods, but it was the one that caused more satisfaction.

There are other equally interesting variants, and one of the most striking is the so-called “magic carpet” which even has its own website and promises the best results. Referring to the program “Myth Hunters” in which the best was the inverse pyramid with about 15 minutes of boarding time, the magic carpet would achieve shipments of 13 minutes that could even be lower.

Studies in this field are surprisingly numerous: we have the Michael Schultz and Hartmut Fricke (2011), plus an update from the same authors and a third contributor, Thomas Kunze (2013).

Even more recent is the work of Shafagh Jafer and Wei Mi (2017) which concludes that the most appropriate method is the Wilma, but we can also run our own simulations with alternatives such as Simul8, whose responsible coincided with the good behavior of the Wilma method.

Time is money, and more in an air plane

It is difficult to know what factors airlines take into account when developing their boarding systems, but it is clear that the economic factor is one of the most important.

In fact, a study of the impact of flight delays published by the University of Berkeley in California showed how an estimate of the total cost of flight delays in the United States cost the industry $32.9 billion, of which $16.7 billion had a “passenger component.

A stopped plane costs between 40 and 337 dollars when stopped, the study said, so saving on boarding times should be a priority for these airlines.

This is another reason why some airlines require different additional payments depending on which cabin baggage we carry or which one we want to check: being clear about what we are going to carry and pay before can save more than a displeasure, and not only does it allow airlines to earn extra revenue, but they can also better organize boarding and reduce times with these measures.

Such measures have become the norm in highly controversial airlines such as Ryanair, which has long charged between EUR 6 and EUR 10 for hand luggage if we are foresighted, but that amount amounts to more than EUR 25 if we carry more hand luggage than is permitted at the boarding gate.

These measures work, of course, and charging more for checking in any type of baggage is one of the systems to increase revenue: in 2016 alone, US airlines received 4.2 billion dollars for this type of payment, accounting for 2.5% of their total revenue that year.

This measure does not comply with the Spanish regulations of the Air Navigation Law, but it is also that the conditions of each airline vary on a fundamental issue such as the measurements of suitcases allowed for cabin luggage, which are different depending on the company. The consensus here is non-existent, something that generates additional stress among passengers.

Some airlines do try to improve on this. American Airlines spent two years studying its boarding processes and came to the conclusion that a partially random system based on zones was the most appropriate. A little later it introduced a modification, and allowed passengers who didn’t need to put anything in the cabin compartments to have priority in boarding.

How are boarding groups created?

Each airline uses different boarding procedures involving different parameters. These parameters include the priority of passengers – whether they are members of loyalty programs, frequent flyers, etc. – what they have paid for the ticket or even the boarding systems they use on that airline.

This means that we may encounter situations that should be analogous in different companies but are not: often those who pay an extra have higher shipping priority.

In the meantime, groups with lower priority may have rented a car next to the passenger or a hotel and a group that embarks later could do so because they have paid only for the ticket without any extra, but this argument is often mixed with others that result in different situations.

In StackExchange they explained for example how in American Airlines for example the priority is for first class passengers, then business class, then high level frequent passengers, low level and then groups 1 to 4.

Group 1 would have paid an extra to board earlier or paid by credit card. In group 2 there would be people who use online check-in or who have a connecting flight with another airline, group 3 is people who use one of the ticketing terminals at the airport and group 4 is people who get a boarding pass with an agent, for example when checking in.

This system is different from United Airlines, which uses very different groups from 1 to 5. Group 1 includes first and business class passengers as well as high level frequent flyers. Group 2 would include the remaining frequent flyers, people who have paid for earlier boarding, and people with United credit cards.

Group 3 would include all passengers who go in window seats, while group 4 would include the remaining passengers who sit in the middle seat and group 5 would include the remaining passengers (aisle seats).

In Spain the same thing happens and each airline has its own procedure. Iberia, for example, has four groups, while uqe Vueling has three different groups and Ryanair, as we explained in depth a few months ago, has its own method of maximising extra revenue after buying the ticket.

There are group boarding processes of all types, and for example Lufthansa has different policies for different types of flight. In the long distance (outside Europe) while Japan Airlines has a process in which after the pre-boarding used by many airlines (people with temporary or permanent disabilities, families with small children) embark priority passengers (First, Business, frequent travelers) and then go to a boarding back to front.

There are many conclusions to be drawn from this analysis. First and foremost, that airlines do not have a unified, standard process that could help make everything easier for passengers, who are disadvantaged by these differences. The second is that economic revenue is once again being sent.

And third, that science and data seem to matter very little: there are theoretically better methods than the airlines use for boarding, but they don’t seem interested in taking advantage of them. As we mentioned at the beginning, let us hope that some of them will read to us and consider changes in a system that would not only be beneficial for passengers, but also for them thanks to time savings.

This robot not only flies, it compresses to enter small spaces.

The FSTAR hybrid (flying sprawl-tuned autonomous robot) is not only a robot capable of flying like a quadricopter, but of driving in difficult terrain and transforming itself to access reduced spaces, using the same engines, as you can see in the following video.

FSTAR will be presented at the 2019 International Conference on Robotics and Automation in Montreal on 21 May.

Developed at Ben-Gurion University in the Negev by Mechanical Engineering professor David Zarrouk and his graduate student, Nir Meiri, the FSTAR adjusts its width to crawl or run on flat surfaces, climb large obstacles and climb very separate walls, or go through a tunnel, pipe or narrow spaces.

He can also run on the ground at speeds of up to 2.6 meters per second, as Zarrouk explains:

We plan to develop larger and smaller versions to expand this family of extensive robots for different applications, as well as algorithms that will help exploit the speed and transport cost of these flying robots/drivers.

NASA funds cryogenic hydrogen system to power all-electric aeroplanes

Advances in engine systems have increased flight efficiency over the last few decades, but dependence on fossil fuels means that aircraft continue to contribute to greenhouse gas emissions.

To solve this problem, NASA, together with specialists from the University of Illinois, proposes the idea of using sustainable energy sources instead of fossil fuels for commercial aircraft, with a view to the introduction of cryogenic hydrogen.


The Center for High Efficiency Cryogenic Electric Technologies for Aircraft (CHEETA) will investigate the technology needed to produce a practical all-electric design to replace conventional fossil fuel propulsion systems. Although the project is still in its conceptual stage, and there are still several technical hurdles to overcome, researchers have a firm vision of the technology and its potential.

Basically, the program focuses on the development of an all-electric aircraft platform that uses cryogenic liquid hydrogen as a method of energy storage.

The chemical energy of hydrogen is converted into electrical energy through a series of fuel cells, which power the ultra-efficient electric propulsion system. The low temperature requirements of the hydrogen system also provide the opportunity to use superconducting or lossless power transmission.

The CHEETA project is a consortium of eight institutions including the Air Force Research Laboratory, Boeing Research and Technology, General Electric Global Research, Ohio State University, Massachusetts Institute of Technology, University of Arkansas, University of Dayton Research Institute and Rensselaer Polytechnic Institute.

Something important for us to start relying on autonomous cars: that they show feedback like humans.

Perhaps, in a short time, we will discover and collectively assume that autonomous cars are much safer than cars driven by humans. However, until that time comes, we are going to have to take intermediate steps to ensure that people do not feel uncomfortable or tense.

When we are going to cross a zebra crossing, for example, we underestimate the importance of creating a mind theory of the car’s conduit that is about to cross just above that zebra crossing as well.

That is, we can make eye contact with the driver, warn that he has seen us, or signal to the driver that we have seen him. That he wants to stop, or that he pretends to continue. All this non-verbal language based on predicting intentions is impossible if the driver of the autonomous car is an algorithm. We cannot create a theory of mind from an algorithm.

First steps

A possible solution to this problem has been proposed by, a company that operates autonomous vans in Texas. The bright orange and blue vehicles have LED signs on all four sides that respond to the context with messages to provide some feedback not only to pedestrians, but also to eventual occupants of the vehicle.

These signals can tell a pedestrian who wants to cross in front of the car something like “I’ll wait for you to pass” or they can warn him: “Wait for me to pass”.

A related strategy is aimed at passengers, not pedestrians: screens on Waymo vehicles show car occupants a simple, animated version of what the autonomous vehicle is seeing. These screens can also show what the vehicle is doing, as if it were stopping to allow a human to cross.

All of which means that if vehicles are predictable and do what they say they will do, people are more likely to trust them. Little by little.

Reducing energy costs associated with cooling buildings by up to 50% is possible with this new wood.

A ‘cooled wood’ can reduce the cost of air conditioning a home by 50%, because this new wood-based material, designed by scientists at the universities of Maryland and Colorado, successfully reflects heat or infrared radiation.

Buildings account for more than 40% of total U.S. energy demand, almost half of which is used for heating and cooling.

Eight times stronger
This wood is eight times stronger than natural wood, is highly reflective and capable of passive radiative cooling.

To achieve this, the researchers improved the qualities of the material by compressing the wood that has been stripped of its lignin (polymers that help harden plant cells), and impregnated it with impressive mechanical and radiative cooling properties.

The complete denitrification and deification process not only makes the wood significantly stronger, but also produces partially aligned cellulose nano fibers, giving the cooling wood its highly solar-reflective surface and high infrared emissivity.