Piezoelectric

As per the Regional Human Development Report of the United Nations
Development Programme (UNDP) on April 26, 2016, India’s working population
between the ages of 15-64 will rise above 1 billion by 2050. Working in a
professionally driven environment is highly cumbersome at times; especially, when the
individual is surrounded with the office and household responsibilities. Household
responsibilities include various things such as taking care of the grocery stocks,
paying various bills on time and other basic daily chores. While fulfilling official
duties, it is common for the working individual to be oblivious to his household
responsibility. While it is difficult to take care of others’ professional work, domestic
work can be easily taken care. Through this project, we intend to reduce the
significant amount of time devoted by people on replenishing their groceries by
providing them with the concept of ’Smart jar’. Apart from refilling the items, through
the A.I. model this project not only selects the desired quality, but also a type of
delivery based on an individual’s buying pattern at the least possible price. This new
concept can be a revolutionary as it intends for a paradigm shift in the conventional
grocery shopping technique.

While most microbes play an important role in nature, certain potentially harmful microbes can contaminate food and water, and cause a plethora of infectious diseases in both animals and humans. Conventional methods for detecting microbial contamination have primarily ...

Autonomous systems present the future of wireless networks and applications. Systems that are able to go anywhere and be truly "autonomous" have a huge advantage over those dependent on finite power sources. They do not require regular maintenance of a battery; therefore they can be put into places where it might be difficult to replace components. The question is "How

ABSTRACT
INTRODUCTION: Maxillofacial bone defects occur for various reasons as infections, tumor and cysts or physiologic loss of bone after
extraction of teeth. There are a lot of controversies among dental practitioners in the material used for filling of bone defects to increase the
volume of bone in favor of good placement of the implant. Autogenous bone is the gold standard for bone reconstruction due to osteogenic,
osteoinductive, and osteoconductive properties.
OBJECTIVES: The aim of this study was to evaluate clinically and radiographically the efficiency of using maxillary tuberosity as a block
bone graft for augmentation of anterior maxillary defects.
MATERIALS AND METHODS: Twelve patients with anterior maxillary bone defects were treated with bone graft harvested from the
maxillary tuberosity with an age range of 20 and 50 years old. Piezotome 2 was used for bone harvesting from the tuberosity. Osteosynthesis
microscrews were used to fix the block graft in place.
RESULTS: Bone density and width showed statistical significant difference detected by cone beam computed tomography (CBCT).
CONCLUSIONS: The large and accessible maxillary tuberosity is a reliable source to use as autogenous bone block for augmentation of jaw
defects
KEYWORDS: Autogenous bone graft, maxillary tuberosity, guided bone regeneration (GBR), piezosurgery.

Book Description This monograph covers the fundamentals, fabrication, testing, and modeling of ambient energy harvesters based on three main streams of energy-harvesting mechanisms: piezoelectrics, ferroelectrics, and pyroelectrics. It addresses their commercial and biomedical applications, as well as the latest research results. Graduate students, scientists, engineers, researchers, and those new to the field will find this book a handy and crucial reference because it provides a comprehensive perspective on the basic concepts and recent developments in this rapidly expanding field.

1. Pengertian dan Sejarah
Piezoelektrik berasal dari bahasa Yunani yaitu piezo yang artinya tekanan dan elektrik yang berarti listrik. Bahan piezoelektrik adalah suatu bahan yang apabila diberi stress (tekanan) mekanik akan menghasilkan medan listrik sebaliknya apabila medan listrik diterapkan pada bahan piezoelektrik akan terjadi deformasi mekanik atau perubahan dimensi bahan.[1]
Piezoelektrik ini untuk pertama kalinya di temukan pada tahun 1880 oleh dua orang bersaudara pieze curie dan Jacques curie, dan akhirnya pada tahun 1950 piezoelektrik dapat diaplikasikan untuk alat-alat industri setelah memalui proses yang panjang. Sejak itu, pemanfaatan prinsip pengukuran ini telah mengalami pertumbuhan konstan dan dapat dianggap sebagai teknologi yang matang dan telah berhasil digunakan dalam berbagai aplikasi seperti misalnya di medis, aerospace, instrumentasi nuklir dan mobile pad touch screen sebagai sensor tekanan.[2]
Jacques dan Pierre Curie mengombinasikan pengetahuan akan piroelektrisitas (kemampuan bahan‐bahan tertentu untuk menghasilkan sebuah potensial listrik saat bahan‐bahan itu dipanaskan atau didinginkan) dengan pemahaman akan struktur dan perilaku sebuah kristal pada kristal turmalin, kuarsa, ratna cempaka, dan garam rossel. Dari uji coba tersebut diketahui bahwa kristal kuarsa dan garam rossel memperlihatkan kemampuan piezoelektrisitas paling besar saat itu.
Piezoelektrik didefenisikan sebagai suatu kemampuan yang dimiliki sebagian kristal maupun bahan-bahan tertentu lainnya yang dapat menghasilkan tegangan listrik jika mendapatkan perlakuan tekanan atau  regangan. Piezoelektrik adalah suatu efek yang reversibel, dimana terdapat efek piezoelektrik langsung (direct piezoelectric effect) yaitu produksi potensial listrik akibat adanya tekanan mekanik dan efek piezoelektrik balikan (converse piezoelectric effect)  yaitu produksi tekanan akibat pemberian tegangan listrik yang menghasilkan perubahan dimensi (Triwahyuni, 2010).
Bahan piezoelektrik adalah suatu bahan yang apabila diberi stress(tekanan) mekanik akan menghasilkan medan listrik sebaliknya apabila medan listrik diterapkan pada bahan piezoelektrik akan terjadi deformasi mekanik (perubahan dimensi bahan).
Karakteristik dari bahan piezo elektrik adalah :
1. Bisa mengubah energi mekanik menjadi energi listrik dan sebaliknya.
Kesebarisan mutualisme antara momen-momen dipol dari suatu sel satuan yang jumlah nya banyak ini menghasilkan polarisasi dimana muatan positif terkumpul di salah satu ujung dan muatan negatif diujung yang lainnya. Perhatikan gambar  (b) dan (d). Kompresi (atau tarik) kristal dengan tegangan s. Akan terdapat regangan e, yang ditentukan oleh modulus elastisnya. Regangan ini akan mengubah panjang dipol d dan langsung mempengaruhi polarisasinya(=ΣQd/v) karena Q dan V pada dasarnya adalah konstan. Dengan polarisasi yang lebih kecil (dari kompresi), akan terdapat kelebihan densitas muatan pada kedua ujung kristal tersebut . jika kedua ujung kristal tersebut diisolasi , beda tegangan akan terjadi(gambar b). Tidak ada tekanan yang dikeluar pada gambar (d). Alih-alih, diberikanlah suatu tekanan yang menaikkan densitas muatan pada kedua ujung . muatan-muatan negatif dalam bahan , tertarik ke suatu arah yang sama dan muatan-muatan positifnya tertarik ke arah yang lawannya, sehingga mengubah tidak hanya panjang dipolnya (d), tetapi juga dimensi bahan(kristalnya). Alat yang memiliki kemampuan seperti ini disebut material tranduser .[8]


Bahan Piezoelektrik terbentuk oleh keramik yang terpolarisasi sehingga beberapa bagian molekul bermuatan positif dan sebagian yang lain bermuatan negative membentuk elektroda ‐elektroda yang menempel pada dua sisi yang berlawanan dan menghasilkan medan listrik material yang dapat berubah akibat gaya mekanik. Pada saat medan listrik melewati material, molekul yang terpolarisasi akan menyesuaikan dengan medan listrik, dihasilkan dipole yang terinduksi dengan molekul atau struktur Kristal materi. Penyesuaian molekul akan mengakibatkan material berubah dimensi. Fenomena ini disebut electrostriction (efek piezoelektrik). Fenomena efek piezoelektrik dapat digambarkan sebagai berikut:[7]

(A) Sebelum diberi tekanan atau medan listrik.
(B) Ketika diberi medan listrik, bahan memanjang.
(C) Diberi medan listrik berlawanan, bahan memendek.
(D) Ketika diberi tekanan, induksi polarisasi dan tegangan luar terjadi.

This paper evaluates a new and simple controller design method based on QFT (quantitative feedback theory) for a two-link manipulator whose first link is rigid and the second is flexible. A piezoelectric patch is attached to the surface of the flexible link for vibration suppression of it. This system is modeled as a nonlinear multi-input multioutput (MIMO) control systems whose inputs are two motor torques which are applied on the joints and a voltage which is applied on the piezoelectric patch. To control the manipulator’s end point position, motion of the manipulator is divided to two rigid and flexible parts. To control both parts, nonlinear equations of the motion is replaced by a family of uncertain linear time-invariant equivalent systems using Rafeeyan-Sobhani’s method(RS method) which results in three decoupled transfer functions established in the Laplace domain. Then the QFT method is used to design a diagonal matrix as the prefilter of the system an another diagonal matrix as the system controller. Results demonstrate the remarkable performance of the proposed controllers in reduction of residual vibration of elastic link and tracking a circular trajectory by the manipulator end point.

The piezoelectric devices, based on micro–nano electromechanical systems, are well known nowadays due to their small features, ability for integration with the integrated circuit in a single platform, robust, and easily fabricated in bulk. The enhanced performance of piezoelectric systems, which is soft, flexible, and stretchable made them have unique opportunities to be used in bio-integrated applications as nanodevices for energy harvesting, sensing, actuation, and cell stimulation. The selection of optimized configurations depends on thin geometries, neutral mechanical plane construction, and controlled buckling, while inorganic piezoelectric materials are preferred for interfaces with human bodies. The key considerations in designs, the analytical derivations for voltage and displacement, and the effect of the voltmeter resistance on the voltage measurements are presented. Devices for energy harvesting from natural motions of internal organs, sensors, and actuators for medical applications are reviewed. The PMN-PT energy harvester that produced current of 0.22 mA is higher than the rest of the discussed harvesters. Thus, it is more suitable to be used as a sufficient source of energy in biomedical applications. The use of piezoelectric nanowires and ribbons proved successful, and the dual features of device (sensor and actuator) seem advantageous.

Piezoelectric properties and adequate porosity play important roles in bone tissue engineering. In this paper we describe the fabrication of piezoelectric polypropylene (PP) foam using injection molding to be utilized as a potential cost-effective scaffold for bone tissue engineering. One-side mechanical skin removal from the foam was used to investigate the effect of the solid skin on the piezoelectric performance. The microcellular structure, relative density, crystalline structure, mechanical properties, piezoelectric properties under repeated impact pressure and biocompatibility of the scaffolds were investigated using scanning electron microscopy (SEM), water displacement method, differential scanning calorimetry (DSC), uniaxial tension tests, piezoelectric tests and MTT assays, respectively. Uniform spherical cells, with an average size of 75 mm and a density of 1.23 Â 10 6 cells/cm À3 , suitable for bone regeneration, were imaged by SEM. The DSC results showed b crystals formation in the PP foam during the foaming process which would be valuable for mechanical properties. The foaming process did not reduce the mechanical properties significantly. The foaming process promoted the piezoelectric responses by 134, 922, and 87%, respectively, for the PP samples with 3, 2 and 1 mm thickness. The biocompatibility test suggested improved cellular biocompatibility by foaming. Overall, the results demonstrated the development of a cost-effective scaffold for tissue engineering. ARTICLE HISTORY

Altering the natural frequencies of slender thin walled laminated composite beams by changing its stiffness has been reported
in the literature. This had been performed either using optimal mechanical and thermal induced stresses or using
collocated piezoelectric patches bonded on the structure. It was shown that for the cases of a beam equipped with piezoelectric
patches, restraining the beam’s axial displacements at its two ends can lead to either softening or stiffening of the
beam stiffness, as a function of the voltage supplied to the patches.
However, when those structures behave like a cantilevered beam, or a free-free beam, classical beam theories show that the
lateral vibrations of those beams cannot be altered by applying a constant electric voltage to the collocated surface bonded
piezoelectric layers or patches. This occurs because the resultant force on each cross section of the beam is always identically
zero (due to the fact that no axial external forces are applied on the beam).
It is the aim of the present manuscript to show that under certain circumstances one can alter also the natural frequencies
of a cantilevered piezo laminated beam. The present paper will investigate this phenomenon, and provide a new insight
into this topic.

Piezoelectric utilization as a generator is an effort to obtain electrical energy that refers to the concept of energy harvesting referring the development of piezoelectric as a generator that converts the pressure or vibration generated from steps into electrical energy that can be used on low-power electronic devices. Because the use of piezoelectric as a generator allows the use in charging low voltage, a larger resource is required in different series. Based on the problem, an energy harvesting device and a voltage amplifier are created to increase the voltage of the pizoelectric output. An arduino microcontroller is used to control the energy harvesting device and voltage booster. It is required approximately 10 steps to charge four AA 1.2 Volt batteries and 80 steps to charge two 12 volt batteries respectively.

This paper proposes a robust control methodology for piezoelectric actuation systems to track specified motion trajectories. This is motivated by the search for an effective control strategy to deal with the problem of nonlinear behaviour in the piezoelectric actuation systems. The basic concept associated with this approach lies in the specification of a target performance and the formulation of a robust control scheme for the system to ensure the convergence of the position tracking error to zero in the presence of parametric uncertainties and hysteresis effect inclusive of other un-modelled disturbances. Stability of the control system is proven theoretically and the robust control methodology is demonstrated to possess a promising tracking ability through the control experiments. Implementation of the control law requires only a knowledge of the estimated parameters and their corresponding bounds as well as the bound of the hysteresis effect including disturbances. Being capable of handling uncertainties and disturbances, the robust control methodology is very attractive in the field of micro/nanomanipulation in which high-precision control applications could be realised

Traveling Wave Ultrasonic Motor (TWUM) is a compact, precise, and silent actuator generating high torque at low speed without gears. Moreover, the TWUM has a high holding torque without supply, which makes this motor as an attractive solution for holding position of robotic arms. However, their nonlinear dynamics, and the presence of load-dependent dead zones often limit their use. Those issues can be overcome in closed loop with effective and precise controllers. In this paper, robust H-infinity (H∞) and discrete time RST position controllers are presented. The H∞ controller is designed in continuous time with additional weighting filters to ensure the robustness in the case of uncertain motor model and external disturbances. Robust RST controller based on the pole placement method is also designed and compared to the H∞. Simulink model of TWUM is used to validate the stability and the robustness of the two proposed controllers