Final Na Final

7/25/2019 Final Na Final

http://slidepdf.com/reader/full/final-na-final 1/46

Technological University of the Philippines

Taguig Campus

Km 14 East Service Rd Western icutan Taguig City

AN ALTERNATIVE SOURCE OF ENERGY USING HYBRID P-TEG (PIEZO-TRIBOELECTRIC GENERATOR)

! STU"# PRESE$TE" T% T&E '!CU(T# %' T&E

E(ECTR%$)CS E$*)$EER)$* "EP!RT+E$T

)n Partial 'ulfillment of the re,uirements for the

achelor-s "egree of Electronics and Communications Engineering

Su.mitted .y/

4SE 0 SEcE

!pale 2ayson T3

!urino 'rancis 2oseph +3

(oriaga 2ohn Eric '3

+agana +erry 2oy +3

Rivera Kevin S3

Su.mitted to/

Engr3 "anilo +3 +iranda

2une 5617

Chapter 1



AN ALTERNATIVE SOURCE OF ENERGY USING HYBRID P-TEG (PIEZO-TRIBOELECTRICGENERATOR) 2016

A222

THE PROBLE AND ITS BAC!GROUND

1"1 I#tr$%&'t$#

)magine life 8ithout electricity3 )s it possi.le to survive a day or 8ee 8ithout

using computers and cellular phones9 %r last a moment 8ithout using daily

appliances such as television refrigerator 8ashing machine etc39

)t is really hard to live a life 8ithout electricity3 !t present it has .ecome a .asic

necessity in life :ust lie food and 8ater3 )n this moderni;ation period the electrical

consumption of man drastically increases along 8ith the 8orld-s increasing

population together 8ith the ne8 innovations and concepts in technology3 !s long as

this pro.lem e<ists it 8ill .ecome a hassle to manind in the near future and if

remain unsolved electricity 8ill soon .e gone3

$o8adays scientists and researchers all across the glo.e are searching for

alternatives in producing electricity3 !s of no8 people can supply their homes .y

using solar energy 8hich is coming from the sun or .y using 8ind energy 8hich is

coming from 8indmills3 !lso they can simply use 8ater to produce hydroelectric

energy or tur.ines 8hich converts mechanical energy to electricity .y the help of

generators3

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!nother promising 8ay to generate energy 8ithout harming the environment is

the &y.rid P=TE*3 )t com.ines the energy harvesting capa.ility of a pie;oelectric

and the materials that produces the so=called tri.oelectric effect3

1" Ba'*+r$&#% $, the t&%.

+any countries specifically Philippines e<perienced great po8er loss3 This

drastic diminishing of electrical energy in every country is 8hat this pro:ect inspires to

do3

!ccording to the la8 of thermodynamics any mechanical stress or e<ternal

forces applied can .e a great pro.a.le source of energy3 &o89 y using pie;o

material 8e can convert this mechanical 8ave into electric signals3 The pie;oelectric

effect descri.es the relation .et8een mechanical stress and an electrical voltage in

solids3 !n applied mechanical stress 8ill generate a voltage and an applied voltage

8ill change the shape of the solid .y a small amount3 )n electronics a pie;oelectric

material is a type of transducer that can convert energy from one form to another

especially converting the sound energy into electrical energy3 Transducers are found

from microphones loudspeaers etc3

)n this technology era there 8ill al8ays .e an update 8hen it comes to

innovations .ecause man must fulfill his needs in life3 Transducers can no8 .e

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A222

su.stituted .y pie;oelectric sensors 8hich are no8 used in research and control3

Pie;oelectric sensor is a device that uses pie;oelectric effect 8hich had .een

discussed to measure changes in pressure acceleration temperature strain or

force .y converting them to an electrical charge3 The said electronic device 8ill .e

used in this pro:ect as a purpose of converting the applied forces into electrical

charges>signals3

Tri.oelectric generators 8ere introduced in 5615 and 8ere firstly demonstrated

.y a group of students in *eorgia )nstitute of Technology in the year 56153 !s for this

po8er generation unit in the inner circuit a potential is created .y the tri.oelectric

effect due to the charge transfer .et8een t8o thin organic>inorganic films that e<hi.it

opposite tri.o=polarity? in the outer circuit electrons are driven to flo8 .et8een t8o

electrodes attached on the .ac sides of the films in order to .alance the potential3

The tri.oelectric generator can .e applied to harvest all ind mechanical energy that

is availa.le .ut 8asted in daily life such as human motion 8aling vi.ration

mechanical triggering rotating tire 8ind flo8ing 8ater and more3

The com.ination of .oth materials can produce much more efficient and relia.le

source of energy since they .oth e<hi.ited the purpose of generating electricity .y

means of mechanical force such as vi.ration3 This study 8ill help the researchers to

understand if there is a change of output po8er 8hen the t8o sources of energy

com.ined3

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1"/ State0e#t $, the Pr$2e0

The pro.lem of a pie;oelectric generator is its lo8 output3 !ccording to 2edol

"ayou @5A the po8er output from a single pie;oelectric film is very lo8 at the range

of 635 micro8atts3 )n this condition direct application of the pie;oelectric film as a

po8er source is not yet practical3 This leads the researchers to conduct this study on

ho8 to increase the output of a pie;oelectric .y adding Teflon that 8ill esta.lish the

so=called tri.oelectric effect3

1"3 O4e't5e $, the t&%.

1"3"1" Ge#era2 O4e't5e

The general o.:ective of the pro:ect is to create a hy.rid generator that

applies the theories and principles of pie;oelectric and tri.oelectric effect maing it a

good source of energy3

1"3"" Spe',' O4e't5e

The specific o.:ectives of this study are to/

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13 "esign and construct a hy.rid P=TE*53 "esign and construct an energy harvesting circuit3B3 "esign a platform to protect the said device and to 8ithstand the force

of a footstep of a human43 Test analy;e and evaluate the output of the hy.rid pie;oelectric

material and tri.oelectric generator and compare it to the outputs of only a

pie;oelectric material 8ithout tri.oelectric effect3a3 'unctionality test

The test includes/1313 +easurement of the voltage and current that the hy.rid P=TE*

gives off 1353 The consistency of generating electricity

13B3 Production of electricity that can charge a .attery1343 Testing the output po8er of the hy.rid P=TE*

.3 "ura.ility TestThe test includes/

1313 'orce applied on the hy.rid P=TE*S+#,'a#'e $, the St&%.

T$ the reear'her

This study 8ill help the researcher gain further no8ledge to discover a

uni,ue or more effective 8ay to apply the principles of pie;oelectric and tri.oelectric

effect for harvesting energy3

T$ the E2e'tr$#' Depart0e#t

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The pro:ect 8ill help .roaden the no8ledge of the faculty and the students in

the electronics department to innovate and research further the concept of the

pro:ect3

T$ the t&%e#t

The pro:ect is intended to increase the a8areness of students in utili;ing the

a.undant rene8a.le energy around the environment3

S'$pe a#% De20tat$#

S'$pe

• This pro:ect intends to demonstrate the effect of tri.oelectricity 8hen

applied to a pie;oelectric material3

• +echanical vi.ration 8ill .e used as input in the pro:ect3

• Can .e used to drive lo8 po8er electronic devices

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De20tat$#

• The pro:ect is limited for application inside the university

• The pro:ect is limited only in charging a .attery

• +easuring ho8 long the machine can last 8ill not .e covered

Chapter II

REVIE6 OF RELATED LITERATURE AND STUDIES

A" Reear'h 2terat&re

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A222

1" Pe7$e2e'tr't.

Pie;oelectricity is the electric charge that accumulates in certain solid materials

such as crystals certain ceramics and .iological matter such as .one "$! and

various proteins in response to applied mechanical stress3 The

8ord piezoelectricity means electricity resulting from pressure3 )t is derived from

the *ree piezo or piezein 8hich means to s,uee;e or press

and electric or electron 8hich means am.er an ancient source of electric

charge3 Pie;oelectricity 8as discovered in 1DD6 .y 'rench

physicists 2ac,ues and Pierre Curie3

Pie;oelectric effect is understood as the linear electromechanical interaction

.et8een the mechanical and the electrical state in crystalline materials 8ith

no inversion symmetry3 The pie;oelectric effect is a reversi.le process in that

materials e<hi.iting the direct pie;oelectric effect the internal generation of electrical

charge resulting from an applied mechanical force also e<hi.it the reverse

pie;oelectric effect the internal generation of a mechanical strain resulting from an

applied electrical field3 'or e<ample lead ;irconate titanate crystals 8ill generate

measura.le pie;oelectricity 8hen their static structure is deformed .y a.out 631F of

the original dimension3 Conversely those same crystals 8ill change a.out 631F of

8

https://en.wikipedia.org/wiki/Electric_charge

https://en.wikipedia.org/wiki/Crystal

https://en.wikipedia.org/wiki/Ceramic

https://en.wikipedia.org/wiki/DNA

https://en.wikipedia.org/wiki/Protein

https://en.wikipedia.org/wiki/Stress_(physics)


https://en.wikipedia.org/wiki/Greek_language

https://en.wikipedia.org/wiki/Amber

https://en.wikipedia.org/wiki/Jacques_Curie

https://en.wikipedia.org/wiki/Pierre_Curie

https://en.wikipedia.org/wiki/Poling_(piezoelectricity)

https://en.wikipedia.org/wiki/Centrosymmetry

https://en.wikipedia.org/wiki/Reversible_process_(thermodynamics)

https://en.wikipedia.org/wiki/Force

https://en.wikipedia.org/wiki/Lead_zirconate_titanate

https://en.wikipedia.org/wiki/Crystal

https://en.wikipedia.org/wiki/Ceramic

https://en.wikipedia.org/wiki/DNA

https://en.wikipedia.org/wiki/Protein


https://en.wikipedia.org/wiki/Greek_language

https://en.wikipedia.org/wiki/Amber

https://en.wikipedia.org/wiki/Jacques_Curie

https://en.wikipedia.org/wiki/Pierre_Curie

https://en.wikipedia.org/wiki/Poling_(piezoelectricity)

https://en.wikipedia.org/wiki/Centrosymmetry

https://en.wikipedia.org/wiki/Reversible_process_(thermodynamics)

https://en.wikipedia.org/wiki/Force

https://en.wikipedia.org/wiki/Lead_zirconate_titanate

https://en.wikipedia.org/wiki/Electric_charge




A222

their static dimension 8hen an e<ternal electric field is applied to the material3 The

inverse pie;oelectric effect is used in production of ultrasonic sound 8aves3

Pie;oelectricity is found in useful applications such as the production and

detection of sound generation of high voltages electronic fre,uency

generation micro.alances to drive an ultrasonic no;;le and ultrafine focusing of

optical assem.lies3 )t is also the .asis of a num.er of scientific instrumental

techni,ues 8ith atomic resolution the scanning pro.e microscopies such

as ST+ !'+ +T! S$%+ etc3 and everyday uses such as acting as the ignition

source for cigarette lighters push=start propane .ar.ecues and ,uart; 8atches3

" Pe7$e2e'tr' E,,e't

Pie;oelectric Effect is the a.ility of certain materials to generate an electric

charge in response to applied mechanical stress3 The 8ord Pie;oelectric is derived

from the *ree pie;ein 8hich means to s,uee;e or press and pie;o 8hich is *ree

for GpushH3

%ne of the uni,ue characteristics of the pie;oelectric effect is that it is reversi.le

meaning that materials e<hi.iting the direct pie;oelectric effect the generation of

electricity 8hen stress is applied also e<hi.it the converse pie;oelectric effect the

generation of stress 8hen an electric field is applied3

9

https://en.wikipedia.org/wiki/Microbalance

https://en.wikipedia.org/wiki/Ultrasonic_nozzle

https://en.wikipedia.org/wiki/Scanning_probe_microscopy

https://en.wikipedia.org/wiki/Scanning_tunneling_microscopy

https://en.wikipedia.org/wiki/Atomic_force_microscopy

https://en.wikipedia.org/wiki/Microthermal_analysis

https://en.wikipedia.org/wiki/Scanning_near-field_optical_microscopy

https://en.wikipedia.org/wiki/Lighters

https://en.wikipedia.org/wiki/Barbecue#Natural_gas_and_propane

https://en.wikipedia.org/wiki/Quartz_clock


https://en.wikipedia.org/wiki/Microbalance

https://en.wikipedia.org/wiki/Ultrasonic_nozzle

https://en.wikipedia.org/wiki/Scanning_probe_microscopy

https://en.wikipedia.org/wiki/Scanning_tunneling_microscopy

https://en.wikipedia.org/wiki/Atomic_force_microscopy

https://en.wikipedia.org/wiki/Microthermal_analysis

https://en.wikipedia.org/wiki/Scanning_near-field_optical_microscopy

https://en.wikipedia.org/wiki/Lighters

https://en.wikipedia.org/wiki/Barbecue#Natural_gas_and_propane





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When pie;oelectric material is placed under mechanical stress a shifting of

the positive and negative charge centers in the material taes place 8hich then

results in an e<ternal electrical field3 When reversed an outer electrical field either

stretches or compresses the pie;oelectric material3

The pie;oelectric effect is very useful 8ithin many applications that involve the

production and detection of sound generation of high voltages electronic fre,uency

generation micro.alances and ultra fine focusing of optical assem.lies3 )t is also the

.asis of a num.er of scientific instrumental techni,ues 8ith atomic resolution such

as scanning pro.e microscopes ST+ !'+ etc3 The pie;oelectric effect also has

its use in more mundane applications as 8ell such as acting as the ignition source

for cigarette lighters3

/" Te,2$#

Polytetrafluoroethylene PT'E or Teflon is a synthetic fluoro polymer of

tetrafluoroethylene that has numerous applications3 The .est no8n .rand name of

PT'E=.ased formulas is Teflon .y Chemours3 Chemours is a spin=off of "uPont Co3

8hich discovered the compound in 1IBD3

PT'E is a fluorocar.on solid as it is a high=molecular=8eight compound

consisting 8holly of car.on and fluorine3 PT'E is hydropho.ic/ neither 8ater nor

10

https://en.wikipedia.org/wiki/Fluoropolymer

https://en.wikipedia.org/wiki/Tetrafluoroethylene

https://en.wikipedia.org/wiki/Chemours

https://en.wikipedia.org/wiki/Corporate_spin-off

https://en.wikipedia.org/wiki/DuPont

https://en.wikipedia.org/wiki/Fluorocarbon

https://en.wikipedia.org/wiki/Molecular_weight

https://en.wikipedia.org/wiki/Carbon


https://en.wikipedia.org/wiki/Fluorine

https://en.wikipedia.org/wiki/Hydrophobic

https://en.wikipedia.org/wiki/Fluoropolymer

https://en.wikipedia.org/wiki/Tetrafluoroethylene

https://en.wikipedia.org/wiki/Chemours

https://en.wikipedia.org/wiki/Corporate_spin-off

https://en.wikipedia.org/wiki/DuPont









A222

8ater=containing su.stances 8et PT'E as fluorocar.ons demonstrate

mitigated (ondon dispersion forces due to the high electronegativity of fluorine3

PT'E has one of the lo8est coefficients of friction of any solid3

The ma:or application of PT'E consuming a.out J6F of production is for 8iring

in aerospace and computer applications e3g3 hooup 8ire coa<ial ca.les3 This

application e<ploits the fact that PT'E has e<cellent dielectric properties3 This is

especially true at high radio fre,uencies maing it suita.le for use as

an insulator in ca.les and connector assem.lies and as a material for printed circuit

.oards used at micro8ave fre,uencies3 Com.ined 8ith its high melting temperature

this maes it the material of choice as a high=performance su.stitute for the 8eaer

and lo8er=melting=point polyethylene commonly used in lo8=cost applications3 PT'E

can .e taen as a measuring matri< for characteri;ing the performance of the

material in the tri.oelectric nanogenerators TE$*3

3" Tr$e2e'tr' E,,e't

The tri.oelectric effect occurs 8hen materials .ecome electrically charged after

they come into contact 8ith another different material through pressing together or

friction 8hich greatly enhances the effect3 'or e<ample ru..ing glass or a plastic

com. 8ith fur or 8ool can trigger tri.oelectricity3

11

https://en.wikipedia.org/wiki/London_dispersion_force

https://en.wikipedia.org/wiki/Electronegativity

https://en.wikipedia.org/wiki/Friction

https://en.wikipedia.org/wiki/Dielectric

https://en.wikipedia.org/wiki/Radio_frequency

https://en.wikipedia.org/wiki/Electrical_insulation

https://en.wikipedia.org/wiki/Cable

https://en.wikipedia.org/wiki/Electrical_connector

https://en.wikipedia.org/wiki/Printed_circuit_board


https://en.wikipedia.org/wiki/Microwave

https://en.wikipedia.org/wiki/Polyethylene





https://en.wikipedia.org/wiki/Dielectric

https://en.wikipedia.org/wiki/Radio_frequency

https://en.wikipedia.org/wiki/Electrical_insulation

https://en.wikipedia.org/wiki/Cable

https://en.wikipedia.org/wiki/Electrical_connector



https://en.wikipedia.org/wiki/Microwave





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)n a simplistic 8ay its possi.le to say that materials in most cases insulating

materials are charged 8hen electrons are ru..ed off .y the atoms of one material

from another3 ut the actual process is ,uite complicated3 !fter coming into contact

.y friction or ru..ing a chemical .ond is formed .et8een some parts of the t8o

surfaces called adhesion and as a result electrical charges move from one material

to the other in a complicated 8ay3

The material that LstealsL electrons from the other is said to have a stronger

affinity for electrons negative charge3 !fter separation this material has a surplus of

electrons and the meaning is that its surface 8ill .ecome negatively charged and in

the same 8ay the other material 8hich lost electrons 8ill .ecome positively charged3

"ifferent materials have different a.ilities to tae electrons from other materials =

8hat is called electron affinity3 +aterials 8ith a higher electron affinity are supposed

to LstealL electrons from materials 8ith lo8er affinities and as a result to .e

negatively charged3 +aterials could .e arranged in an ordinary 8ay according to

their relative strength of affinity = 8hat 8e call tri.oelectric series3

+ost everyday static electricity phenomena are tri.oelectric3 ecause the surface

of a certain material is electrically charged .y a ru..ing effect either negatively or

positively any contact 8ith an uncharged conductive o.:ect or 8ith an o.:ect having

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an opposite charge may cause an electrical discharge in an attempt to e,uali;e the

electrical charges and this triggers a spar3

8" E#er+. Har5et#+

Energy harvesting also no8n as po8er harvesting or energy scavenging is the

process .y 8hich energy is derived from e<ternal sources e3g3 solar po8er thermal

energy 8ind energy salinity gradients and inetic energy captured and stored for

small 8ireless autonomous devices lie those used in 8eara.le electronics and

8ireless sensor net8ors3

Energy harvesters provide a very small amount of po8er for lo8=energy

electronics3 While the input fuel to some large=scale generation costs resources oil

coal etc3 the energy source for energy harvesters is present as am.ient

.acground and is free3 'or e<ample temperature gradients e<ist from the operation

of a com.ustion engine and in ur.an areas there is a large amount of

electromagnetic energy in the environment .ecause of radio and television

.roadcasting3

13

https://en.wikipedia.org/wiki/Energy

https://en.wikipedia.org/wiki/Solar_power


https://en.wikipedia.org/wiki/Wearable_computer

https://en.wikipedia.org/wiki/Sensor_network

https://en.wikipedia.org/wiki/Energy


https://en.wikipedia.org/wiki/Wearable_computer

https://en.wikipedia.org/wiki/Sensor_network




A222

9" Batter.

!n electric .attery is a device consisting of one or more electrochemical cells 8ith

e<ternal connections provided to po8er electrical devices3 ! discharging .attery has

a positive terminal or cathode and a negative terminal or anode3 The terminal

mared negative is the source of electrons that 8hen connected to an e<ternal circuit

8ill flo8 and deliver energy to an e<ternal device3 When a .attery is connected to an

e<ternal circuit electrolytes are a.le to move as ions 8ithin allo8ing the chemical

reactions to .e completed at the separate terminals and so deliver energy to the

e<ternal circuit3 )t is the movement of those ions 8ithin the .attery 8hich allo8s

current to flo8 out of the .attery to perform 8or3 &istorically the term L.atteryL

specifically referred to a device composed of multiple cells ho8ever the usage has

evolved to additionally include devices composed of a single cell3

B" Reear'h St&%e

a" F$re+# St&%e

1" E#er+. Har5et#+ ,r$0 Ra#%$0 Vrat$# $, Pe7$e2e'tr' Ca#t2e5er

a#% Sta'* (Sh$#+ Zha$)

Electromechanical modeling efforts in the research field of vi.ration=.ased

energy harvesting have .een mostly focused on deterministic forms of vi.rational

input as in the typical case of harmonic e<citation at resonance3 &o8ever am.ient

14

https://en.wikipedia.org/wiki/Electrochemical_cell


https://en.wikipedia.org/wiki/Cathode


https://en.wikipedia.org/wiki/Anode

https://en.wikipedia.org/wiki/Electrolyte



https://en.wikipedia.org/wiki/Anode

https://en.wikipedia.org/wiki/Electrolyte




A222

vi.rational energy often has .roader fre,uency content than a single harmonic and

in many cases it is entirely stochastic3 !s compared to the literature of harvesting

deterministic forms of vi.rational energy fe8 authors presented modeling

approaches for energy harvesting from .road.and random vi.rations3 These efforts

have com.ined the input statistical information 8ith the single=degree=of=freedom

S"%' dynamics of the energy harvester to e<press the electromechanical

response characteristics3 )n most cases the vi.rational input is assumed to have

.road.and fre,uency content such as 8hite noise3 White noise has a flat po8er

spectral density PS" that might in fact e<cite higher vi.ration modes of an

electroelastic energy harvester3 )n particular cantilevered pie;oelectric energy

harvesters constitute such continuous electroelastic systems 8ith more than one

vi.ration mode3

The main component of this thesis presents analytical and numerical

electroelastic modeling simulations and e<perimental validations of pie;oelectric

energy harvesting from .road.and random e<citation3 The modeling approach

employed herein is .ased on distri.uted=parameter electroelastic formulation to

ensure that the effects of higher vi.ration modes are included3 The goal is to predict

the e<pected value of the po8er output and the mean=s,uare shunted vi.ration

response in terms of the given PS" or time history of the random vi.rational input3

The analytical method is .ased on the PS" of random .ase e<citation and

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distri.uted=parameter fre,uency response functions of the coupled voltage output

and shunted vi.ration response3

" E#er+.-Har5et#+ Street T2e Ge#erate P$:er ,r$0 Pa5e0e#t P$&#%er

(;1/)

These special GEnergy &arvesting TilesH 8ere developed .y (ondon=.ased

Pavegen Systems3 The po8er thus generated can .e used to run lo8=voltage

e,uipment such as streetlights and vending machines3 The concept is the .rainchild

of (aurence Kem.all=Coo 8ho founded Pavegen in 566I to commerciali;e it3

Pavegen uses 8hat it calls a hy.rid .lac .o< technology to convert the energy

of a footstep into electricity 8hich is either stored in a .attery or fed directly to

devices3 ! typical tile is made of recycled polymer 8ith the top surface made from

recycled truc tires3 ! foot stomp that depresses a single tile .y five millimeters

produces .et8een one and seven 8atts3 These tiles generate electricity 8ith a hy.rid

solution of mechanisms that include the pie;oelectric effect an electric charge

produced 8hen pressure is e<erted on crystals such as ,uart; and induction 8hich

uses copper coils and magnets3

Pavegen is not alone in harvesting human inetic energy to generate electricity3

+a< "onelan founder of Canada=.ased ionic Po8er 8hich has developed a

8eara.le nee .race that harvests energy 8hile 8aling says the .races Gcan .e

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useful 8hen you need electricity 8ithout having to rely on the po8er grid3 'or

e<ample our nee .races are .eing developed for military use in places lie

!fghanistan 8here .attery cells are e<or.itantly e<pensive3H

Energy=harvesting tiles may .e :ust one step for man .ut taing many such

steps may lead to a more po8erful and sustaina.le future3

/" F#+er t.p#+ %r5e# tr$e2e'tr' #a#$+e#erat$r a#% t &e ,$r

#ta#ta#e$&2. 2+ht#+ &p LED (;1)

&arvest mechanical energy 8ith varia.le fre,uency and amplitude in our

environment for .uilding self=po8ered systems is an effective and practically

applica.le technology to assure the independently and sustaina.le operation of

mo.ile electronics and sensor net8ors 8ithout the use of a .attery or at least 8ith

e<tended lifetime3 )n this study 8e demonstrated a novel and simple arch=shaped

fle<i.le tri.oelectric nanogenerator TE$* that can efficiently harvesting irregular

mechanical energy3 The mechanism of the TE$* 8as intensively discussed and

illustrated3 The instantaneous output po8er of singlet TE$* device can reach as

high as M4315J mW .y a finger typing 8hich is high enough to instantaneously drive

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J6 commercial .lue (E"s connected in series demonstrating the potential

application of the TE$* for self=po8ered systems and mo.ile electronics3

3" Star'ae P$:er Ge#erat$# U#+ Pe7$-E2e'tr' Tra#%&'er (B.< V"

Praa##aa2a4= R" Ra*eh= S" Sara0 a#% S" aheh= Electronics and

Instrumentation Engineering,,Sri SaiRam Engg College, Chennai. )

With the decrease in energy consumption of porta.le electronic devices the

concept of harvesting rene8a.le energy in human surrounding arouses a rene8ed

interest3 )n this conte<t 8e are proposing the prototype of a pie;oelectric generator

that harvests mechanical vi.rations energy availa.le on a Staircase3 Em.ared

pie;oelectric transducer 8hich is an electromechanical converter undergoes

mechanical vi.rations therefore produce electricity3 ! static converter transforms the

electrical energy in a suita.le form to the targeted lighting application3

8" A N$5e2 Ar'h-Shape Na#$+e#erat$r Bae% $# Pe7$e2e'tr' a#%

Tr$e2e'tr' e'ha#0 ,$r e'ha#'a2 E#er+. Har5et#+

! simple and cost=effective approach 8as developed to fa.ricate pie;oelectric

and tri.oelectric nanogenerator P=TE$* 8ith high electrical output3 !dditionally

pyramid micro structures fa.ricated atop a polydimethylsilo<ane P"+S surface

8ere employed to enhance the device performance3 'urthermore pie;oelectric

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.arium titanate T nanoparticles and multi8alled car.on nanotu.e +WC$T 8ere

mi<ed in the P"+S film during the forming process3 +ean8hile the composition of

the film 8as optimi;ed to achieve output performance and favora.le toughness 8as

achieved after thermal curing3 !n arch=shape )T%>PET electrode 8as attached to the

upper side of the polari;ed composite film and an aluminum film 8as placed under it

as the .ottom electrode3 With periodic e<ternal force at 56 &; electrical output of

this P=TE$* reached a pea voltage of 55 N and current of I O! 8ith a pea current

density of 131B O!>cm5 8hich 8as si< times that of the tri.oelectric generator

8ithout T and +WC$T nanoparticles3 The nanogenerator can .e directly used to

lighten 5D commercial light=emitting diodes (E"s 8ithout any energy storage unit

or rectification circuit under human footfalls.

" L$'a2 St&%e1" E2e'tr't. Ge#erat#+ F$$t:ear - Ge#erate E2e'tr't. B. 6a2*#+"evelopment of the Pro:ect/

The po8er generating soles are one of the first concept pro:ects3 &e started his

first prototype last five years ago although it 8as a very primitive compared to his

current design3 &is old prototype had t8o to three plastic spacer sand8iched

.et8een t8o pie;o=discs3 )t produces a fair amount of current enough to charge a

$oia BB163

Concept .ehind The Pro:ect/

Pie;oelectricity 8as present ever since mid=1Dth century3 Pie;oelectricity is

19




A222

the electric charge that accumulates in certain solid materials such as crystals

certain ceramics in response to applied mechanical stress3 #ou can actually find

those pie;o elements in your old> outdated earphones from the I6s3

" A%apt5e pe7$e2e'tr' e#er+. har5et#+ 'r'&t

This pro:ect descri.es an approach to harvesting electrical energy from a

mechanically e<cited pie;oelectric element3 a vi.rating pie;oelectric device differs

from a typical electrical po8er source in that it has a capacitive rather than inductive

source impedance and may .e driven .y mechanical vi.rations of varying

amplitude3

!n analytical e<pression for the optimal po8er flo8 from a rectified pie;oelectric

device is derived and an energy harvesting circuit is proposed 8hich can achieve

this optimal po8er flo83

The harvesting circuit consists of an ac=dc rectifier 8ith an output capacitor

an electrochemical .attery and a s8itch=mode dc=dc converter that controls the

energy flo8 into the .attery3 !n adaptive control techni,ue for the dc=dc converter is

used to continuously implement the optimal po8er transfer theory and ma<imi;e the

po8er stored .y the .attery3 E<perimental result reveal that the use of the adaptive

dc=dc converter increases po8er transfer .y over 466F as compared to 8hen the

dc=dc converter is not used3

20




A222

/" I#-:hee2 Pe7$e2e'tr' Ge#erat$r ,$r L+ht#+ App2'at$# $, ##+

Tr$22e. (;11)

Electricity has .een a necessity in todays culture3 This is 8hy harvesting

allo8a.le form of energy .ecome relevant3 There are many 8ays of generating

alternative energy3 %ne e<ample is through a transducer called the pie;oelectric

crystal3 The pie;oelectric crystal generates electric charges on its surface 8hen

mechanical strain is applied to it3 That is 8hy pie;oelectric crystals are ideal for

heavy 8eight pressure3 ! perfect e<ample for this ind of pressure is the 8eight in

the 8heels of a mining trolley3

Since these carts carry very intense mining loads the 8eight can .e ma<imi;ed

.y inserting a pie;oelectric transducer to the 8heels to harvest energy3 The potential

generated from the 8heels can .e used in the lighting of the mining trolley and

having this ind of energy the consumption of electrical energy may .e minimi;ed

from po8er line companies3 The purpose of this study is to generate energy using

pie;oelectric crystals .y applying great pressure to it through the 8heels of a mining

trolley3 This 8ill serve as an alternative po8er source in supplying energy to the

lighting of the mining trolleys3 With this o.:ective the study aims to minimi;e energy

21




A222

consumption from po8er plants and instead generate energy in a more efficient and

practical 8ay3

'" C$#'ept&a2 Fra0e:$r*

This study 8ill re,uire inputs from Kno8ledge People8are and &ard8are3 )t

8ill re,uire the e<pertise of an Electronics Engineer for the circuit and for the concept

designing3 !pplying hard8are 8ill .e a great help to improve the pro:ect such as for

analysis and designing process3

The process sho8n .elo8 'ig31 tacles the undergoing of the statement of

the pro.lem to clearly define the mindset of 8hat the researchers 8ill .e addressing

in the pro:ect study3 Clearly e<plaining or defining the statement of the pro.lem 8ill

serve as guidelines for the researchers for data gathering and to collect information

a.out the concepts of the pro:ect3 !fter collecting the desired data needed for the

study there 8ill .e a system design 8hich 8ill apply the concepts and ideas that the

researchers gathered3 !fter this prototype development follo8s3 This process 8ill

apply the designed system that the researchers made3 $e<t 8ill .e the testing of the

prototype3 This 8ill initially test the said prototype and 8ill chec if it 8ors and>or if it

ans8ered the stated pro.lem3 )f the prototype fails or doesn-t 8or the researchers

8ill need to redesign the prototype and retest again if it no8 8ors3 %nce the

redesigned prototype 8ors developing its final system development comes ne<t

22




A222

and 8ill ready for the final testing and evaluation3 )f it 8ors the second time around

the researchers 8ill implement its system as to .e 8oring3

The fulfillment of the process 8ill conclude the pro:ect concept of &y.rid P=

TE*3

23



INPUTOUTPUTPROCESS

edge

tor system design

nality of the electronic components of the system used

cal !no"ledge

ser

ity

ware

nic &ircuit %ngineers

cians

are

$e 'ridge recti(er

ectric ensor

,egulators

ectric generator .o

/es

.o

/es

AN ALTERNATIVE SOURCE OF ENERGY USING HYRI

tatement of the )ro'lem

ata Gathering and ,esearch

ystem esign

)rototype e$elopment

oring

-esting

Final ystem e$elopment

-esting and %$aluation

oring

ystem mplementation


A222

24

Fig. 1




A222

C" De,#t$# $, Ter0

E#er+. Har5et#+ 'r'&t

- Circuit used for collecting unconventional source of energy such as

mechanical vi.ration3 The circuit consists of t8o full8ave .ridge rectifier and

a capacitor

H.r% p$:er

= Com.ination .et8een different technologies to produce po8er3

H.r% P-TEG

= !lso called hy.rid pie;o=tri.oelectric generator3

Pe7$e2e'tr' e,,e't

- The a.ility of certain materials to generate an electric charge in response to

applied mechanical stress3

Pe7$e2e'tr' ,20

= Polyvinylidene 'luoride or PN"' or Pie;oelectric 'ilm is a specialty plastic

material in the fluoropolymer family? it is used generally in applications

25




A222

re,uiring the highest purity strength and resistance to solvents acids .ases

and heat and lo8 smoe generation during a fire event3 Compared to other

fluoropolymers it has an easier melt process .ecause of its relatively lo8

melting point of around 1 QC3

Te,2$#

= Polytetrafluoroethylene or PT'E or Teflon is a fluorocar.on solid as it is a

high=molecular=8eight compound consisting 8holly of car.on and fluorine3

PT'E is hydropho.ic/ neither 8ater nor 8ater=containing su.stances 8et

PT'E as fluorocar.ons demonstrate mitigated (ondon dispersion forces due

to the high electronegativity of fluorine3 PT'E has one of the lo8est

coefficients of friction of any solid

Tr$e2e'tr' e,,e't

= a type of contact electrification in 8hich certain materials .ecome electrically

charged after they come into frictional contact 8ith a different material3

Tr$e2e'tr' Na#$+e#erat$r (TENG)

26




















A222

- is an energy harvesting device that converts the e<ternal mechanical energy

into electricity .y a con:unction of tri.oelectric effect and electrostatic

induction3

Chapter III

RESEARCH DESIGN

A" Pr$4e't C$#'ept&a27at$#

27

-ri'oelectric.anogenerato

%nergy

har$ester circuit+i'rationnput

atter

y)ie*oelectric

generator

https://en.wikipedia.org/wiki/Energy_harvesting

https://en.wikipedia.org/wiki/Triboelectric_effect


https://en.wikipedia.org/wiki/Energy_harvesting





A222

Fig. 2 Project Conceptualization

The mechanical vi.ration coming from the footstep of a person stepping onto

the pro:ect 8ill .e the input of the process3 The pro:ect consists of t8o 5 processes

from a single Gtouch and releaseH activity3 )n the touch activity the arch layered that

consists of pie;oelectric film 8ill mae contact to the Teflon3 Pie;oelectric film has

positive charges 8hile Teflon has negative charges so it 8ill undergo tri.oelectric

effect 8herein the opposite charges 8ill attract to each other causing electrical

charges3 When it reaches in the release activity there 8ill .e a separation of the t8o

.ut there 8ill .e an electric charge in the pie;oelectric film due to the phenomenon

called pie;oelectric effect3 )n the end there 8ill .e a simultaneous production of

electrical charges and these charges 8ill .e captured .y an energy harvester circuit

and .e stored into a .attery3

Upon pressing or stepping on the upper part of the device it 8ill undergo in

the effect called Gtri.oelectric effect3H The positive charges on the pie;oelectric film

and negative charges in the teflon 8ill attract to each other until they create electric

28




A222

charges 8hich are analog signals as sho8n in 'ig3 B3 The charges 8ill then .e

captured .y the energy harvesting circuit and stored into the .attery

Upon releasing on the upper part of the device 8hich you had stepped on

the materials pie;oelectric materials and teflon 8ill not .e in contact no8 so they

8ould .e neutral3 !side from this the pie;oelectric material 8ill undergo in the

process called Gpie;oelectric effectH coming from the material itself3 Upon releasing

the mechanical stress in the material it 8ill create charges 8hich 8ill .e passing

through the energy harvesting circuit as analog signals as sho8n in 'ig3 4 and then it

8ill .e stored into a .attery3

29

%nergy

har$esti'gcircuit

attery -ri'o %lectric

generator

#ser

nput

nalog

Fig. 3 ri!oelectric generator "lo#

%nergyhar$esting

circuit

)ie*oGenerato

attery#sernput

nalo

Fig. $ Piezoelectric generator "lo#




A222

B" Pr$4e't De+# a#% I#tr&0e#tat$#

The generator is made up of four materials namely/ Teflon PT'E

pie;oelectric film PN"' Polyimide 'ilm P) and aluminum electrodes3 The

pie;oelectric film and the P) film are arch=shaped to ensure that the device e<hi.its

pie;oelectric effect .y pressing or stepping3 The purpose of the P) film is to

strengthen the pie;oelectric film from tensile or compressive stress3 The

pie;oelectric film is the main component in the production of pie;oelectricity and it

has positively charges to .e used for the attraction of the negatively charges coming

from the Teflon to produce tri.oelectricity3 The Teflon is a measuring matri< to for

characteri;ing the performance of the material3 The aluminum electrode underneath

30

Fig. % Project &esign




A222

the Teflon has the purpose of improving the negative charges of the Teflon3 The

dimension of this device is 53JH<37BH<637H3

The device has three connecting 8ires pie;oelectric input tri.oelectric input

and ground3 The t8o inputs 8ill .e connected to the energy harvesting circuit and

then .e connected to the .attery for storage3

31

Fig. '.( Plat"orm &esign

)IS*+ERIC IE-




A222

32

Fig. '.2 Plat"orm &esign

FR*/ IE-

Fig. '.3 Plat"orm &esign

)RI01 SI&E IE-




A222

The proposed pro:ect consists of t8o pieces of (ight8eight Wood sheets four

pieces of arch = shape hy.rid P=TE* four pieces of springs t8o pairs of metal

support a metal guide and a .lac casing that contains the energy harvesting circuit3

The pro:ected dimension for the aluminum sheet is 17-- < D-- < 1--3 )t is given

that in .et8een of the t8o light8eight 8ood sheets are four pieces of arch 0 shape

hy.rid pie;o 0 tri.oelectric generator3 !dding a spring on each of the four corners of

the platform 8ill ena.le it to move up and do8n3 To ensure that the height of the

platform 8on-t e<ceed a metal support 8ill .e attached at the .ac and the front of

the platform3 To ensure also the s8aying of the platform a guide supported in each

side of the platform is attached3!fter securing everything the generator 8ill .e

connected to the .lac casing 8hich contains the energy harvesting circuit3

C" Pr$4e't De5e2$p0e#t

&-+-/),).%.- . F% , ),

1 2 3 4 5 6 7 8 9 10

11

12

13

14

),): F - :%- -;,%% <3= ),%&- --:%

):%#,.:,G

G.,+%,

33




A222

%:%&-. F .% F -;% -;,%% <3= ),%&- --:% / -;% #%&-

+%,

):%#,.:,GG.,+%,

&.-,#&-. F&;)-%, 1 . :: F

- &).%.-

):%

#,.:,GG.,+%,

%:%&-. F -;%),%&- --:% F -;%&: . F+% <5= --:%/ -;% #%&- +%,

):%#,.:,GG.,+%,

+.G F -;% &:.- F+% <5= G,#)

-; 5>6 %%,

):%#,.

:,GG.,+%,

,%+. F &;)-%, 1. :: F -&).%.-

):%

#,.:,GG.

,+%,

&.-,#&-. F&;)-%, 2 . 3 .

:: F - &).%.-

):%

#,.:,GG.

,+%,

#. F -;%&):%-% &;)-%, -

-;% #%&- +%,

):%

#,.:,GG.

,+%,

34

a!le (. 0antt chart +ethods o" Research




A222

The ta.le sho8s the activities during +ethods of Research and the

involvement of each mem.er3 The first activity is started 8ith selecting three pro:ect

titles to .e proposed to the su.:ect adviser .y each student3 The su.:ect adviser 8ill

choose only one pro:ect proposal to each student and each proposal must have

Chapter 13 !fter that the su.:ect adviser 8ill choose only five title proposals among

the 57 proposals and thus creating five groups for those proposals3 With the groups

that have .een created revision of chapter and construction of chapter 5 and B 8ill

tae place3 The moment the activities are finished it 8ill no8 .e su.mitted to the

su.:ect adviser3

&-+-/),).%.- ),: /

1 2 3 5 6

%:%&-. F -;%+%,

):%#,.:,GG.,+%,

&):%-. F&;)-%,

1? 2? 3

):%#,.:,GG.,+%,

&.+.G F-%,:

):%#,.:,GG.,+%,

):%#,.

35




A222

&.#:--. F -;%+%,

:,GG.,+%,

Ta.le 5 sho8s the activities that had .een done during summer3 Each group

must have at least one thesis adviser for consultation The adviser 8ill chec the

papers of the pro:ect3 When the activity is finished the group must canvas materials

and e,uipments needed for the pro:ect3 !fter the said activity consultation of thesis

adviser 8ill tae place3

&-+-/),).%.- #.% #:/ #G %)

1 2 3 4 5 6 7 8 9 10

11

12

13

14

&.#:--.?)#,&;.G F

%@#)%.-A-:

):%#,.:,GG.,+%,

),--/)% !.G

):%

#,.:,GG.,+%,

-%-.G . %+:#-.

):%#,.:,GG.,+%,

&):%-. F ))%,. &#%.-

):%#,.

:,GG.

36

a!le 2. 0antt chart Summer




A222

,+%,

),--/)% %F%.%

):%#,.:,GG.,+%,

The pro:ect is under development and still is conceptuali;ing3 The ta.le a.ove

sho8s the possi.le division of la.or per 8ee .y every mem.er in the group3 )n the

first activity the pro:ect must .e consulted and a list of materials must have in order

to go to the second activity3 )n prototype maing the researchers must create a

prototype that 8ill sho8 the concept of their thesis3 !fter that the prototype must .e

tested and evaluated if there 8ill .e pro.lems in the device3 )f there is the

researchers must create a solution and go .ac to create an improved prototype3 )f

the prototype has good results the researchers must finish the papers and

documents for the final defense3

&-+-/ 3, -%,

),).%.- . F% , ),1 2 3 4 5 6 7 8 9 1

011

12

13

14

,%+. F &;)-%, 4):%

#,.:,GG.,+%,

),+%%.- F -;%),--/)%

):%#,.:,G

G.,+%,

37

a!le 3. 0antt chart itle &e"ense and PS(




A222

&.-,#&-. F&;)-%, 5

):%#,.:,GG.,+%,

#,+%/ . %+:#-.

):%#,.:,GG.,+%,

&):%-. F ))%,

):%#,.:,GG.,+%,

F.: %F%.%

):%#,.:,GG.,+%,

D" Pr$4e't A't&a27at$#

>t. U#t Na0e U#t Pr'e T$ta2

1 Pc PT'E 'ilm PJ66366 PJ66366

1 Pc3 Poly)mide Tape

Roll

P1I66366 P1I66366

4 Pcs Pie;oelectric

'ilm

P1666366 P4666366

1 Pc3>Per pac of

16

!luminum

Electrode Strips

PD66366 PD66366

1 Sheet Wooden sheet PBJ6366 PBJ6366

38

a!le $. 0antt chart Proposed PS 2




A222

platform

D Pcs3 *ermanium

diode

P7366 P44366

1 Pc3 )CD6J P166366 P166366

B +eter 1D Solid Wire PJ366 P1J366

1 Pcs3 Capacitor P1366 P1366

T$ta2 P??1;

E" Pr$4e't Tet#+@E5a2&at$#

Testing>E<periment Procedure

The current and voltage outputs of the hy.rid generator is a

measura.le performance3 The outputs in the pie;oelectric generator is

different as in the outputs of the tri.oelectric generator3The researchers must follo8 the steps .elo8 to measure test and

evaluate the output results of the device according to its functionality and

dura.ility3

1" 'unctionality

i3 Circuitry design

a3 Construct the hy.rid generator according to the structural design3

39

a!le . 4ill o" +aterials




A222

13 Connect the positive terminal and ground terminal of the

hy.rid generator to the oscilloscope and onto the signal

generator

53 Connect the oscilloscope to the signal generator

B3 Step on the hy.rid generator to mae it 8or

43 %.serve the voltage and current output on in the

%scilloscope

J3 Ta.ulate the results3

.3 Construct the energy harvesting circuit and connect them to the

.uilt hy.rid generator3

13 Connect the positive terminal and ground terminal of the

circuit to the oscilloscope and onto the signal generator




%scilloscope

J3 Ta.ulate the results and compare them to the previous

results3

ii3 %utput Comparison

40




A222

a3 Remove the Teflon part of the hy.rid generator This set=up 8ill let

the researchers no8 if there is an effect 8hen there is no

tri.oelectricity taing place3

13 Connect the positive terminal and ground terminal

of the hy.rid generator to the oscilloscope and

onto the signal generator




%scilloscope

J3 Ta.ulate the results3

73 Evaluate and compare the results to the result of

the generator having tri.oelectric effect3

53 "ura.ility

i3 Platform "esign

a3 Construct the platform for the hy.rid generator .ased on the

given structural design3

.3 Weight threshold

41




A222

13 !ssign three=five persons 8ith different 8eights

regardless of its age and gender and each of them 8ill

step onto the hy.rid generator

53 +easure the output of the generator .y a multimeter

for each step of each person3

B3 %.serve the results and ta.ulate them3

Evaluation Procedure

Evaluation 8ill .e done through testing and surveys .y ,uestionnaires3 This

8ill .e the most effective 8ay to evaluate the pro:ect .ecause the usa.ility of the

pro:ect 8ill depend on the effectivity of the generator3 The respondents 8ill .e the

students 8ho 8ill test out the device .y stepping on it3

42




A222

Re,ere#'e

Art'2e Re,ere#'e<

13 N3 Prasanna.ala:i et al3 561B3 !dvance in Electronic and Electric

Engineering3 Staircase Po8er *eneration Using Pie;o 0 Electric Transducers

Nolume B p34353 "ayou 23 et al3 566I3 *enerating Electricity Using Pie;oelctric +aterial3

E<perimental Results and "iscussions pg3 J6B3 &oller '3 2ames? Soog "ouglas !? Crouch Stanley R 5663 LChapter 1L3

Principles of )nstrumental !nalysis 7th ed3 p3I43 hao S3 561B3 Energy &arvesting from Random Ni.rations of Pie;oelectric

Cantilevers and Stacs3 LSummaryL pg3 <v

6ete Re,ere#'e<

13 23 hong et al3 'inger typing driven tri.oelectric nanogenerator and its

use for instantaneously lighting up (E"s $ano Energy 5615

http/>>d<3doi3org>1631617>:3nanoen35615311361J53 Tru.in 2ulian What is the The Tri.oelectric Effect9 The Tri.oelectric Effect

%cto.er 5615

http/>>8883physicsdemos3:uliantru.in3com>physicsvideos>tri.oelectriceff

ect3htmlB3 2ohnson Electric356173 $anomotion3The Pie;oelectric Effect3 61 'e.

5617 http/>>8883nanomotion3com>pie;o=ceramic=motor=

technology>pie;oelectric=effect>

43

http://dx.doi.org/10.1016/j.nanoen.2012.11.015

http://www.physicsdemos.juliantrubin.com/physics_videos/triboelectric_effect.html


http://www.nanomotion.com/piezo-ceramic-motor-technology/piezoelectric-effect/


http://dx.doi.org/10.1016/j.nanoen.2012.11.015








A222

43 L"uPont = "uPont Completes Spin=off of The Chemours CompanyL3

investors3dupont3com3 Retrieved 5617=6B=61J3 !scas3 56143 Electricity *enerating 'oot8ear = *enerate Electricity y

Waling3 "ec3 5614 http/>>8883instructa.les3com>id>Electricity=*enerating=

'oot8ear>

73 !lley Charles? !t8ood Kenneth 1IB3 Electronic Engineering3 $e8 #or

and (ondon/ 2ohn Wiley Sons3 p3 JB4

https/>>en38iipedia3org>8ii>NoltageregulatorReferences

3 &oro8it; Paul? &ill Winfield 1IDI3 The !rt of Electronics Second ed33

Cam.ridge University Press3 pp3 4404

https/>>en38iipedia3org>8ii>"iode.ridge

D3 "hanan:ay Khadilar !pril 56 561B3 Energy=&arvesting Street Tiles

*enerate Po8er from Pavement Pounder

http/>>8883scientificamerican3com>article>pavement=pounders=at=paris=

marathon=generate=po8er>

I3 et al3 Chenyang5ue) 5614 . 6ey 7a!oratory o" Instrumentation Science

and &ynamic +easurement o" +inistry o" Education, /orth 8ni9ersity o"

China, aiyuan :3::(,

China ,https/>>doa:3org>article>1c5J.IDId7I41B5IefBIe7e54J5Jdf

163C3 "avis and *3 (esieutre L!n actively tuned solid=state vi.ration a.sor.er

using capacitive shunting of pie;oelectric stiffnessL ;. Sound i!ration

44

http://www.scientificamerican.com/author/dhananjay-khadilkar/

https://doaj.org/article/1c25b9879d6941329ef39e6e24525df7

http://www.scientificamerican.com/author/dhananjay-khadilkar/

https://doaj.org/article/1c25b9879d6941329ef39e6e24525df7




A222

vol3 5B5 no3 B pp3 761=1 5666@CrossRefA

http/>>ieee<plore3ieee3org><pl>a.stractReferences3:sp9

tpVarnum.erV16BJ141urlVhttpFB!F5'F5'ieee<plore3ieee3org

F5'<plsF5'a.sall3:spFB'arnum.erFB"16BJ141

113 ustamante $icole !le<andra "3 et al3 56113 Thesis !rchive

http/>>8883dlsu3edu3ph>academics>colleges>coe>research>files>5611>esg=

61=1611=63asp

http://dx.doi.org/10.1006/jsvi.1999.2755

http://dx.doi.org/10.1006/jsvi.1999.2755

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