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MECHANICAL RESONANCE: A QUALITATIVE EXPLANATION

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The concept of Mechanical Resonance is fundamental when we speak about engineering, especially in the field of structures and mechanics. It's a phenomenon regarding the dynamic behaviour of a system (whatever you can think about).  What do we mean by "dynamic behaviour"? Simply, dynamic is what moves, the contrary of static, that is, standing, not moving. From a mathematical and physical point of view, a dynamic phenomenon changes during time, i.e, is described by equations in which time is a variable; instead, a static phenomenon doesn’t depend on time, is described by equations in which time doesn’t appear as a variable. If we take some pictures of a static phenomenon during the time, the pictures are all the same, nothing changed during the time. In reality, every system, although it seems to be static, it moves. Let consider, for example, a house: from a macroscopic point of view, a house is static, but in reality, its structure is continuously subjected to

WHAT IS THERMOGRAPHY ?

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Nowadays there is an increasing interest in innovative techniques used to inspect the internal part of materials to check if some flaws are present inside it, to have a quantitative measure of its mechanical properties. The main goal of these innovative techniques is to test the material without destroying it and for this reason these techniques are called non-destructive inspection techniques (NDT). Thermography is an NDT technique that allows detecting flaws inside a material by mean of observing it with a thermal camera. It is largely diffusing among industries and it's becoming a must in the quality checks and inspection phase. There are applications also in the medical field, for illness (like diabetes and vascular disorder) and tumour detection. In this article I will describe the working principle of thermography, providing some examples of real applications. How thermography works Thermography is based on the observation of a body using a thermal camera , exploiting

HOW DOES A THERMAL CAMERA WORK ?

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A thermal camera is an electronic device that allows transforming the infrared radiation emitted by any kind of body in a coloured image. Indeed, any body whose temperature is greater than 0 K (the absolute zero) emits radiation in the infrared spectrum. This is what we call heat . The infrared radiation is not visible to the human eye, so we need a particular device to visualize it. And here the thermal camera comes. But how does a thermal camera works? And how does it allow us to transform this infrared radiation, that is not visible, into a coloured image that we can see on a screen? Let see it more in detail. How a thermal camera works The scheme describing how a thermal camera works is the following: A sensitive element transforms the infrared radiation, namely, the heat emitted by a body into an electrical charge. This is possible also if the observed body is at a certain distance and really near to the thermal camera; This electrical charge is collected on an electron

MATERIALS FOR SPACE APPLICATIONS: A REVIEW

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The importance of materials for Space applications Space is a really harsh environment, not only for astronauts but also for materials. Radiations, atomic oxygen, outgassing, debris and micrometeorites, high and low temperatures are the main problems materials for Space applications have to deal with. For this reason, a structure that wants to stay in Space has to be made with some specific materials, such that it can guarantee mechanical and functional properties and protect astronauts. Let's describe all these problems more in detail and see which are the main adopted solutions. Radiation Radiations represent the most famous problem in Space related to astronauts health. In fact, materials for Space applications have to be able to protect astronauts but also to maintain their mechanical and functional properties. Radiations are divided into two main categories: UV radiations and ionizing radiations .  UV radiation UV radiation has a really detrimental effect on polymeric

ARTIFICIAL INTELLIGENCE IN SPACE APPLICATIONS

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What's the role of Artificial Intelligence in Space applications ? As we have seen in other articles, the general role of Artificial Intelligence is that of optimizing some functions to be able to perform them with the minimum error or adapt some behaviours of a machine to an unpredictable situation, namely, a situation that is difficult to be predicted during the design phase and that gives us some uncertainties. The role of Artificial Intelligence in Space application is exactly the same: it is used to optimize some functions, performance, adapting a machine to unpredictable, uncertain conditions. In this article, I will present a particular example of how Artificial Intelligence in Space applications is used. In particular, we will see how an automatic lander for comet/asteroids works, adapting itself to really uncertain conditions, difficult to predict during the design phase. A brief introduction to asteroids landings The history of landings on asteroids is not muc

THE LUCKIEST AIRPLANE ACCIDENT

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Introduction to airplane accident  Airplane accidents have guided aviation to improve airplanes over time. The analysis of these catastrophic events revealed weaknesses in airplanes design and gave a better understanding of the phenomenona that can lead to airplane accident. For this reason, each airplane accident had a key role in regulamentations (FFAR) updates and design choices, to make the probability of an airplane accident extremely remote. In this article, I will present one of the most famous airplane accident with an incredible lucky end. The luckiest airplane accident: Boeing 737, Aloha Airlines 243 The Boeing 737 of Aloha Airlines 243 flight, 28 April 1988 is the most famous airplane accident in the history of Aeronautics. The accident happened at an altitude of 7300m An entire part of the fuselage was lost due to a crack propagated from fatigue loads (cyclic loads) generated by pressurization cycles, the so-called GAG (Ground-Air-Ground) cycles. The fracture was born

ARTIFICIAL INTELLIGENCE IN DIGITAL MARKETING

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The Importance of Artificial Intelligence in Digital Marketing The impact of Artificial Intelligence in Digital Marketing is huge. Artificial Intelligence in Digital Marketing allows optimizing the public who will see products and services that a vendor wants to sell. It allows contents and advertisements to reach a potential buyer in a very targeted way. In particular, we are talking about Machine Learning, the branch of Artificial Intelligence whose algorithms are based on possessing a sufficient (usually big... so big!) amount of data.  As we know, all Internet services like Google, Facebook Ads and so on have a big database in which navigation data about every person that signed up are contained. All this data give the possibility to the algorithms to target a specific potential buyer. In this article I will give a general and simple idea of how Artificial Intelligence in Digital Marketing works, explaining why understanding it could be really helpful to take bett

ARTIFICIAL INTELLIGENCE VS MACHINE LEARNING : A CLARIFICATION

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Artificial Intelligence vs Machine Learning There is not a real difference between Artificial Intelligence vs Machine Learning . Artificial Intelligence is, in general, the science whose goal is to optimize a machine to do better what it does, executing an algorithm whose aim is to minimize errors. This is possible through continuous measurements, by sensors, of the performance of the machine, or, in other words, of what the machine is doing and how well is doing it. This is why this science is called Artificial Intelligence: the machine is like to be conscious of what it is doing. But actually, it is not, there is nothing really intelligent. We will see later some examples that will better clarify this introduction. Machine Learning Machine Learning is a branch of Artificial Intelligence.  Machine Learning implements algorithms whose objective is to automatically find out the best answer to a request, namely, to answer with the minimum error.  How? Based on

METAL ADDITIVE MANUFACTURING : HOW IT WORKS

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What is Metal Additive Manufacturing Additive Manufacturing is a technology that allows creating objects adding material layer by layer. In Metal Additive Manufacturing the material involved is metal. There are different types of Metal Additive Manufacturing. Here the most important are reported. Directed Energy Deposition (DED) Metal Additive Manufacturing   Directed Energy Deposition is composed of a head from where a laser, or an electron or a plasma ray exits. On the head, a pressurized system is installed, from where metal powder is ejected in a way that hits the ray and melting occurs. Both the head and component can move. It is possible to use, instead of powder, a filament, cheaper but that gives lower quality. Powder Bed Fusion Metal Additive Manufacturing In Powder Bed Fusion , a bed of powder is deposited and material is melted only where necessary. Once the material is melted, another layer of powder is deposited, and so on. Depending on th