Nanostructured thermoelectric generator for energy harvesting

This paper presents the development processes towards a new generation of nanostructured thermoelectric generators for power harvesting from small temperature gradients by using a combination of traditional silicon microfabrication techniques, electroplating and submicron ion-track nanolithography. Polyimide nanotemplates with pore diameters ranging from 30nm to 120 nm were fabricated. Preliminary results for Bi2Te3 nanowires (50 and 120 nm diameter) electroplated into polycarbonate ion-track commercial membranes are presented. Bi2Te3 nanowires of R ̄ 3m structure, with preferential orientation in the (015) and (110) crystallographic plans with nearly stoichiometric composition were electroplated. The fine-grained observed microstructure (6-10 nm) and (110) crystalline orientation appear extremely promising for improving thermoelectric material properties

An electromagnetic, vibration-powered generator for intelligent sensor systems

This paper describes the design of miniature generators capable of converting ambient vibration energy into electrical energy for use in powering intelligent sensor systems. Such a device acts as the power supply of a microsystem which can be used in inaccessible areas where wires can not be practically attached to provide power or transmit sensor data. Two prototypes of miniature generator are described and experimental results presented. Prototype A is based around two magnets coupled to a coil attached to a cantilever; prototype B is based around four magnets. For prototype A, experimental results are given for its resonant frequency and its open circuit and loaded output as a function of vibration amplitude. For prototype B, experimental results are given for the generator's Q factor in air and vacuum, its output voltage as a function of vibration amplitude as well as its magnetic field strength. This generator has been tested on a car engine and shown to produce a peak power of 3.9 mW with an average power of 157 micro watts

An electromagnetic vibration powered generator for intelligent sensor systems

This paper describes the design of a miniature generator capable of converting ambient vibration energy into electrical energy for use in powering intelligent sensor systems. Such a system can be used in inaccessible areas where wires can not be practically attached to provide power or transmit sensor data. A miniature generator, based around four magnets coupled to a coil attached to a cantilever, is discussed in detail. The miniature generator has been tested on a car engine and has been shown to produce a peak power of 3.9 mW with an average power of 157 µW. Experimental results are also given for the generator's Q factor in air and vacuum, the output voltage as a function of vibration amplitude as well as its magnetic field strength

Design and modelling of a vibration-powered microgenerator

Sensors are being used in increasingly diverse application areas where physical connections to the outside world are difficult. Examples include medical implants, sensors in nuclear processing plants, environmental monitoring and structural monitoring. If the sensor is embedded within a structure, routine maintenance duties such as changing batteries may cause significant problems. The need for having a power supply that will last for the lifetime of the sensor is therefore evident. A popular approach is to use the ambient energy within the environment of the sensor. Possible sources include solar energy, thermal energy from temperature gradients and kinetic energy in the form of environmental vibrations. Each of these approaches offers its own advantages and disadvantages, but of the three techniques mentioned the latter has attracted the least interest to date. The general approach gives rise to the term self-powered microsystem, and a review of such devices is covered by G1ynne-Jones and White]. One of the issues for vibration-based generators is that of energy storage, as the vibrations may not necessarily be present in a continuous and uniform manner. Potential storage media include lithium batteries and super capacitors. The remainder of this paper will be dedicated to the design and modelling of two possible techniques for producing vibration-based generators. The first device is a magnet and coil arrangement where relative movement between the coil and the poles of a permanent magnet generates electricity by electromagnetic induction. The second device is based on using a piezo-electric material to generate electrical energy from vibration-induced deformations (the direct piezo-electric effect). The device is fabricated using thick-film technology, with a piezo-electric paste based on lead zirconate titanate (PZT)2.Analytical solutions have been derived for a wide range of physical effects and, where appropriate, provide a relatively simple technique for modelling microsystem characteristics. In the case of the microgenerator they have been used to calculate resonant frequencies and electrical power output. Finite element analysis (FEA) is a very powerful and flexible technique for modelling complex geometries and is widely used in the design of microsystems. Typically, the structure is divided into a finite number of elements, each with precisely defined material and physical properties, and computers are used to solve the resulting matrix equations. Many FEA packages exist; the work presented here was performed using the ubiquitous ANSYS® software. FEA is particularly useful in microsystems designs to simulate characteristics such as stress distributions, deflections, resonant frequencies and mode shapes, viscous damping effects, piezo-electric coupling and thermal distributions

Micromachined silicon generator for harvesting power from vibrations

Dans cet article, l’auteur explique que, à partir du début des années 1990, une sorte de cercle vicieux s’est noué à travers des processus de criminalisation et de judiciarisation conduisant à une intensification du traitement policier et judiciaire de la délinquance des adolescents (voire des enfants) et se traduisant dans une augmentation des statistiques de prises en charge, augmentation qui laisse croire - à tort - que c’est la réalité comportementale qui se transforme. Pour ce faire, il commence par examiner les données statistiques produites par les administrations policières et judiciaires, en observant notamment les évolutions et éventuelles ruptures survenues depuis les années 1970 et 1980. Puis il les met en parallèle avec les données issues des enquêtes en population générale qui mesurent l’évolution des comportements indépendamment de la réaction institutionnelle. Enfin, pour résoudre les énigmes et les contradictions apparentes entre ces données institutionnelles et ces enquêtes en population générale, il analyse les processus de criminalisation et de judiciarisation à l’œuvre dans la société française.In this article, the author explains that, since the early 1990s, a sort of vicious circle has been established through criminalisation and judicialisation processes leading to an intensification of police and judicial treatment of adolescent (and even child) delinquency and resulting in an increase in the number of cases taken into care, an increase which leads to, wrongly, believe that it is the behavioural reality that is changing. To do this, he begins by examining the statistical data produced by the police and judicial administrations, observing in particular the evolutions and possible breaks that have occurred since the 1970s and 1980s. He then compares them with data from general population surveys that measure the evolution of behaviour independently of institutional response. Finally, in order to solve the enigmas and apparent contradictions between these institutional data and these general population surveys, he analyses the processes of criminalisation and judicialisation at work in the French society.على هذا المقال، يوضح المؤلف أنه بداية من السنوات التسعينات، تشكلت حلقة مفرغة من حلال سيرورات التجريم والإخضاع القضائي المؤدية إلى تكثيف المعاينة الشراطية والقضائية لجنوح المراهقين (حتى لا نقول الأطفال) وهو ما يترجمه ارتفاع الاحصائيات الحاصة بالتكفل، وهو ارتفاع يدفع إلى القول وبالخطأ -أنه الواقع السلوكي هو الذي اصبح يتغير- ولهذا، فإنه يقوم في البداية بمعاينة المعطيات الإحصائية الناجمة عن إرادات الشرطة والقضاء، ومن حلال ملاحظة أيضا التطورات والانقطاعات المحتملة الواقعة منذ سنوات 1970 و1980 ثم يضعها في موازات مع المعطيات الناجمة عن التحقيقات المنجزة في الأوساط العامة للسكان والتي تقيس تطور السلوكيات المستقلة عن ردة الفعل المؤسساتية. في الأخير وحتى يتم فهم المشاكل والتناقضات الظاهرة تبين هذه المعطيات المؤسساتية وهذه التحقيقات في وسط عامة الناس، يحلل المؤلف سيرورات التجريم والاخضاع القضائية المتواجدة في المجتمع الفرنسي