Free Essay

Term Paper Me3281

In: Other Topics

Submitted By thestoner37
Words 4736
Pages 19
ME3281
Microsystems Design and Applications

TERM PAPER

DEPARTMENT OF MECHANICAL ENGINEERING

MEMS Energy Harvesters

LIM HUI HUA ALVINA
A0083044M

2014

Table of Contents

1. Introduction: 2
2. Brief History of Electricity Transduction 2
3. Types of Micro Energy Harvesters 3 3.1 Energy Harvesting from Vibration 3
3.1.1 Fabrication Techniques 5
3.1.2 Applications, Challenges and the Future 6 3.2 Energy Harvesting from Thermal Sources 6
3.2.1 Fabrication Techniques 8
3.2.2 Applications, Challenges and the Future. 9 3.3 Energy Harvesting from Electromagnetic Waves 10
3.3.1 Applications, Challenges and the Future 11 3.4 Energy Harvesting from Light Sources 11
3.4.1 Fabrication 12
3.4.2 Applications, Challenges and the Future 13
4. Conclusion 13
References: 14

1. Introduction:

One of the goals of engineers and scientists in this already tech-savvy age is to be able to design a device that is capable of powering itself for its lifetime without having to replace or recharge its battery using a power chord. These allow remote devices to be placed in hostile or inaccessible environments without requiring any or little maintenance such as the changing of batteries. This is especially applicable for silicon-based electronics, such as biomedical implants that have low power consumption, where batteries will largely affect its size; operational cost of the device, or perhaps even release harmful chemicals into the body. In addition, wireless sensor networks (WSN), which tend to be made up of many small sensors, are being deployed in large amounts. Changing its battery can be rather cumbersome and almost impossible. In these two examples, using Micro-electromagnetic system (MEMS) energy harvesters to extend their lifespan or to even make they self-powered will be an obvious benefit.
There are several ways to harvest energy in the micro scale and we will characterise them by their sources. We are able to harvest micro-energy mainly through vibration/mechanical sources, electromagnetism sources, thermal sources and light sources, each with their own strengths and limitations. In micro energy harvesting for device autonomy, there are 2 situations that need to be considered: when the average rate of harvesting energy is either more or less than the power used by the device. This will affect whether the device runs continuously or intermittently. The choice of which source to use would then depend very much on the applications and the working environment of the device.

2. Brief History of Electricity Transduction
Several methods of generating electricity from the environment used typically by MEMS energy harvesters involve the following phenomena. 1. Electromagnetic Induction 2. Photovoltaic effect 3. Piezoelectric effect 4. Seebeck/thermoelectric effect

Electromagnetic induction is a process where a conductor placed in a changing magnetic field or a conductor moving through a stationary magnetic field causes the production of a voltage across the conductor. This process of electromagnetic induction induces an electrical current. Credit of its discovery was given to Michael Faraday in 1831 who published his findings first. He first discovered this phenomenon when he wrapped an iron wring with 2 insulated coils and found that when a current flowed through one coil, a current was induced in the other coil.
The photovoltaic effect, discovered by Alexandre Edmond Becquerel in 1839 while studying the effect of light on electrolytic cells, refers to the phenomenon “in which two dissimilar materials in close contact produce an electrical voltage when struck by light or other radiant energy”[Encyclopaedia Britannica]. Light energy in the form of photons strikes the electrons of crystals such as Silicon and Germanium and transfers their energy to the electrons. These electrons eventually gain enough energy to be freed from their crystal structure and migrate across the junction where the two materials meet. Migration in one direction is easier than the other, giving rise to a higher concentration of electrons on one side causing a negative charge on that end thus forming a potential difference across the junction.
Pierre and Jacques Curie discovered the piezoelectric effect in the 1880s when they successfully predicted and proved that certain crystals exhibit an electric potential across their sides when they are subjected to mechanical stress. Piezoelectric crystals are crystals whose atomic structure is not symmetrical through out the crystal, but are electrically neutral. A positive charge in one place will cancel out a near by negative charge. When the crystal is deformed, the atoms moving closer together or apart disrupt the balance of the charges. This effect ripples through out the entire crystal which gives rise to a net positive and negative charge on the outer edges of the crystal on opposite sides.
Discovered in 1821 by Thomas Seebeck, thermoelectricity, also known as the Seebeck effect, is a means of generating electrical energy from a difference in temperature on one side of a metal to another. Due to the temperature gradient, electrons start to diffuse from the hot end to the cold end or vice versa, depending on the electrical properties of the metal. If electrons diffuse from the hot side to the cold side, a negative potential difference with respect to the hot side is generated. Likewise, a positive potential difference with respect to the hot side is generated if electrons diffuse from the cold side to the hot side.
3. Types of Micro Energy Harvesters
3.1 Energy Harvesting from Vibration

Figure 1 shows a schematic diagram of a typical MEMS energy harvester that harvests energy from vibrations. Inside the housing there is a seismic mass, m along with a spring, k. When the generator vibrates, the mass moves out of phase with the housing. This leads to an overall net movement of the mass that is sinusoidal in amplitude and is able to drive an appropriate transducer to generate energy.

Fig 1: Schematic of vibrational energy harvester

3 mechanisms can be used to generate electricity from the vibration namely the piezoelectric, electromagnetic and electrostatic phenomena. For this simplified version of a typical energy harvester, C. B Williams and R. B. Yates carried out an analysis. They found that ideally, the power generated is a function of the damping factor, vibration frequency and the resonance frequency as shown in the equation below:
Generated Power=mζtY02ωωn3ω31-ωωn22+ 2ζtωωn2 where ζt the transducer damping factor, ωn is the resonance angular frequency (in radians per second), Y0 the amplitude of vibration and ω the angular frequency of vibration. This equation can be applied to any type of electrical transducer that indicates that the amount of power generated is not affected by the choice of transducer. From the equation above, it shows that the power generated it proportional to ω3, meaning that a larger amount of power will be generated if the device is in an environment that experiences more vibration than a stiller one. The graph plotted for power generated against frequency for different damping factors is shown below.

Figure 2: Graphs of Power-Frequency with different damping factors
From the graph above, we can see that the largest amount of power is generated when the mass vibrates at its resonance frequency. It is also observed that at higher damping ratios, the peak of the graph becomes lower and gentler indicating that the damping factor can be used to control the bandwidth of the device at a trade off with the amount of power generated. For a typical generator, assuming a deflection of 50 μm, power can be generated at 1 μW for 70Hz and 0.1 mW for 330 Hz. It has been found that the load matching condition to transfer the maximum power to the load is given by
Rload=Rint+K2cm.
where Rload is the load resistance, Rint is the coil internal resistance, K is the electromechanical coupling (transducer) coefficient, and cm is the mechanical damping coefficient.
3.1.1 Fabrication Techniques To see how MEMS vibrational energy harvesters are fabricated, we will use an example of a piezoelectric power generator [5]. Given an input force, a cantilever is most compliant among the various common MEMS support structures, which is why it is used in this energy harvester. The main techniques of micro-fabrication used in this example are functional films preparation and pattern, bulk silicon micromachining, structure release and mass assemblage. A brief illustration of the fabrication process is shown in figure 3.

Figure 3: Fabrication Process of Micro Piezoelectric Power Generator (1) Functional films preparation: SiO2/Ti/Pt/PZT/Ti/Pt, (2) functional films pattern, (3) silicon slot etching by RIE, (4) back silicon deep etching by KOH solution, (5) cantilever release by RIE, and (6) metal mass micro fabrication and assemblage. [6]
Step 1: A 500 μm thick (100) oriented silicon wafer is wet oxidized to form a 2 μm thick silicon oxide layer to help improve adhesion between the Ti/Pt electrode and the wafer surface, and acts as a mask during silicon wet etching later.
Step 2: Sputter 30nm of Ti and (111) oriented 300nm of Pt on the oxide layer. Forms bottom electrode.
Step 3: Deposit PZT films by sol–gel method. To obtain perovskite phase PZT film, rapid thermal annealing process at 650oC for 30 min. 1.64 μm thick PZT film layer achieved after 15 coats. Top electrodes Ti/Pt were sputtered on PZT film.
Step 4: Standard photolithography technique used to pattern wafer with prepared films. Back oxide window with align-mark created using HF solution etching. Front electrodes and PZT films were patterned orderly using RIE and wet etching respectively, through double side alignment process.
Step 5: Etched bottom electrodes and Si oxide layers using RIE. Bulk Si micromachining of the wafer’s backside. KOH chemical etching stopped with thin Si layer left before the Si wafer was etched through. Silicon RIE process was then utilized to release composite cantilever.
Step 6: Nickel mass fabricated by UV- LIGA SU-8 technique and is glued onto cantilever. PZT film was poled by applying a 10V DC voltage for 5min after wire bonding process.
3.1.2 Applications, Challenges and the Future

There are several applications for vibrational energy harvesters such as placing one in footwear. Electricity is generated by to the piezoelectric effect when a person deforms a piezoelectric material when he steps or lifts his foot off the ground. The power generated ranges from tens to hundreds of mW and the average energy generated in 1 h, by a running person when the generator is coupled to a resistive load doesn’t exceed 51 mJ. Other applications include powering wireless sensors in industries where other external sources, such as solar and thermal, are not available. Such industries include structural monitoring, roads and bridges, and machine monitoring.
According to Steven Grady from Cymbet Corporation, "The challenge of vibrational energy harvesters has been to find the right device tuned for the specific frequency, and getting enough power out of those frequencies for long enough". We have noted from figure 3 that there is a trade off between power and bandwidth. Therefore, scientists and engineers have been trying to reach the “holy grail of vibration harvesting” which would be a broadband device whose power generated does not fall steeply as the vibration frequency shifts away from the resonance frequency. Although this problem can be worked around by using multiple harvesters with each tuned to a different frequency, this method can be costly. Currently, there is research being conducted into extending the vibrational frequency ranges of mass-spring micro vibrational energy harvesters. They aim to: * tune the system periodically using mechanical or electrical methods which may consuming power intermittently or continuously * broaden the bandwidth by using a generator array, a mechanical stopper, nonlinear springs, or bi-stable structures. [14]
Researchers at the CEA-Laboratory for Electronics & Information Technology, Grenoble, France, have managed to design a device that is able to increase up to 30% of its bandwidth autonomously. Using a piezoelectric tuning with an active powered feedback loop into an electrostatic vibrational energy harvester, all of which only needs less than 5 μW to run, does this. To improve the vibration amplitude and frequency range, nonlinear springs were installed.

3.2 Energy Harvesting from Thermal Sources

At microscales, it can be hard to apply or keep thermal gradients. Hence, usually the different thermal resistances of materials in the MEMS are used to help keep the thermal gradient. Thermal energy harvesters work on the principle of the Seebeck effect. In figure 4, a schematic of a thermocouple and a thermopile is shown.

Figure 4: Schematics of a thermocouple (left) and thermopile (right)

The two legs of the thermocouple are made from 2 dissimilar materials and when there is a temperature difference between the top and bottom of the two pillars, a potential difference will be formed between points A and B. The amount of voltage across the two points is given by
V=α1∆T-α2∆T
where α1 and α2 represent the Seebeck coefficients of materials 1 and 2 respectively and ΔT represents the temperature difference. It is common to use semiconductors for the pillars as they have a large Seebeck coefficient. In addition, the Seebeck coefficient for p-type and n-type semiconductors have opposite signs that add up together, increasing the voltage difference between the two points. The most crucial component of a thermal energy harvester is the thermopile, made up a large number of thermocouples connected thermally and electrically in parallel and series respectively. Other than the thermopile, there may also be a radiator for efficient heat dissipation or thermal shunts to direct the heat passing between the hot and cold ends. In order to optimize the thermal energy harvester, proper design of its components is crucial, such as the dimensions and the number of legs the thermopile should have. In addition, source matching of the thermal and electrical interfaces to the energy source and load matching of the generator to these interfaces are also necessary. In the following, we will take a look at the equations governing the performance of the thermal energy harvester.
A temperature difference of ∆T=WG is formed when W amount of heat flows through a thermopile with total thermal conductance G. G is with reference to a single pillar and air space of the thermopile. It can be shown that the thermal conductance of the air and the pillar need to be the same to maximize the power generated. Therefore, the maximum power condition is expressed as ∆T=W2Gair. For a given length a and height h of the pillars, the number of thermocouples n needed to satisfy the maximum power condition is given by n=Gairh2a2gte where gte is the thermal conductivity of thermoelectric materials, which is the same for the two types of pillars for simplicity. The output voltage will then be ∆V=αn∆T. The equation governing the power of the generator is given as P=164α2ρgteWu2Ahgair where Wu is the heat flow per unit area, A is the area. From these equations, we note that the power is directly proportional to h and that the output voltage is directly proportional to ha2 and therefore, it stands to reason that increasing h will increase both power and output voltage. However, because the ratio of h/a is limited by technology, increasing h to increase power beyond a certain amount will require a to be increased as well. This will then reduce the output voltage because a2 increases faster than h. Therefore there is not a lot of room for concurrent optimization of power and voltage.
3.2.1 Fabrication Techniques

Bi2Te3 is one of the most commonly used materials in these types of energy harvesters, along with Poly-SiGe that is commonly used in micro machined thermopiles. To illustrate the fabrication technique of MEMS thermal energy harvesters, we will examine a design by Till Huesgen. [9]

Fig. 5. Schematic of the microstructured thermoelectric generator with optimized heat flow path. The prototype is fabricated with thermopiles made of n-poly-Si and Al.
Module A:
Step 1: 300 nm thick layers of thermal SiO2 and Si3Ni4 (LPCVD) are deposited onto the wafer to act as electrical insulation and support membrane.
Step 2: In situ n-doped poly-Si is deposited and structured using dry etching. The remaining poly-Si bars are coated with a sputtered Al layer, 250 nm thick and is wet etched to form the winding thermopile. To establish electrical contact between the Al and poly-Si, the wafer is tempered for 60 min at 450◦C.
Step 3: Using PECVD, the thermopile is covered by 1.2 μm of SiO2 to electrically insulate the thermocouples from the electrodeposited gold layer. To allow for electrical contact, the bond pads are opened using dry etching.
Module B:
Step 1: Cr/Au is deposited 20/70 nm thick as a starting layer which is then wet etched so as to prevent heat losses from conduction through the film.
Step 2: One 20 μm thick SU-8-2010 layer is spin-coated on the start layer and structured through photolithography. The rest of the SU-8 structures form trenches above one thermocouple junction, then filled with gold via electroplating.
Step3: Another Au layer is deposited on the whole wafer and structured to insulate the bond pads. the top thermal contact pad is formed using electroplating of gold.
Step 4: The backside of the 300 μm thick Si wafer is structured in Module C. A DRIE process in an STS-ICP, to thermally insulate the thermoelectric structure, releases the membrane. The DRIE process is operated with increasing platen power to yield negative angle walls and a small contact line at the thermocouple junction. Over etching further increases the membrane length as described above.
3.2.2 Applications, Challenges and the Future.

Thermoelectric energy generators (TEG) can be used as a power supply in biomedical implants such as pacemakers or for a body area network where heat is scavenged from the human body. According to V. Leonov who did a research on a TEG mounted on a wrist strap, it was found that the amount of power and voltage produced depends on the number of thermocouples. This is shown in figure 6.

Figure 6: Calculated power and voltage obtainable on a human body with BiTe TEG of the proposed design occupying 1 cm' of the skin with a 5 mm-thick radiator.
Seiko has actually already produced a self-powering watch that used 10 thermopiles fabricated through EDM of sintered BiTe. It registered an output of proximately 300mV when a human wore the watch.
One of the challenges faced with micro TEGs is optimizing the device. According to figure 7, the efficiency of the device increases with temperature gradient, which is difficult to achieve. Thus the device has to be designed very carefully. Another method to increase the efficiency is material optimization. Current research and development is already taking place in the direction of improving the thermoelectric properties through nanostructured materials and super lattices, which may replace Bi2Te3 in the future. This will help in optimizing the output power. In addition, there is also research being done to reduce the size of thermopiles using micromachining.

Figure 7: Efficiency – Temperature difference with different ZT numbers.

3.3 Energy Harvesting from Electromagnetic Waves

Energy from electromagnetic waves in the radio band can be harvested for energy. RF energy is readily available due to public telecommunication services such as GSM or WLAN that have very low power density levels. The basic operation principles of a typical RF energy harvester are as follows.

Figure 8: Schematic of RF harvesting device
There is a matching circuit behind the antenna that matches the power to the schottky diode in order to ensure that the energy is transported through the diode. If the power is not matched, very little energy will be transported. The main aim is to be able to transport all of the energy, of a certain radio frequency, through the diode. It is also possible to match the diode for a wideband antenna, however this will result in low efficiency and quality. For a fixed frequency and power, the output voltage is limited by the voltage sensitivity of the diode.

Figure 9: Schematic of Band-Pass Matching
The impedance matching component shown in figure 9 matches the impedance and works together with the diode like a charge pump. The value and arrangements of the components determine which frequency and power the diode is matched for.
Power density levels for single frequencies range from 0.1 to 1.0mW/m2 between distances of 25 to 100m from a GSM base station. For the total forward channel frequencies, the power levels may be multiplied by a factor between 1 and 3, depending on the amount of traffic. For WLAN, the power levels are at least one order of magnitude lower. Hence, a large area must be used for harvesting RF energy to produce enough energy to power a wireless sensor module. One way to conserve the area required is to use a dedicated RF source that can be placed within close distance to the modules to increase the power density 3.3.1 Applications, Challenges and the Future

RF micro energy harvesters can be used for medical implants that can be used from monitoring heart and respiratory activity to sensing and decoding the signals from a human brain. One such example can be an invasive Brain Machine Interface (BMI). An invasive BMI requires electrodes to be stuck directly into the grey matter of the brain in order to receive and transmit signal clear signals. However, as the tissue tends to attenuate the signal that is transmitted out of the skull, a low noise amplifier (LNA) is required to amplify the signals. This LNA is powered by electromagnetic waves which goes through a charge pump circuit that basically converts a high frequency input signal to a DC output. However, this is not yet ideal as there is much room for improvements to be made to the efficiency and quality. Future research can be done into this area to further improve these systems.

3.4 Energy Harvesting from Light Sources

Energy from light sources is harvested using photovoltaic cells that basically convert the energy from incident photons into electrical energy. Generally, all photovoltaic cells have p-n junction in a semiconductor where the potential difference in developed. Depending on the material used, efficiency can range from 5% to 30%. Photovoltaic cells are usually arranged in a large array, in series, so as to increase potential difference generated. The most common photovoltaic cells are the silicon-based cells as they are more sensitive to light, are easily obtainable and offer a practical price to performance ratio.
One of the factors affecting the amount of energy generated by the harvester is the band gap which is a property of the material. The band gap is the minimum amount of energy required for an electron to break free of its bound state and hence determines how much energy is needed from the sun for conduction and how much energy is generated.

3.4.1 Fabrication

Figure 10: Fabrication Process of Solar Cell
Step 1: A 4000Å layer of SiO2 for electrical isolation is deposited onto a 3” <100> Si wafer substrate by plasma enhanced CVD using silane (SiH4) and nitrous oxide (N2O).
Step 2: 1 μm layer of chromium is deposited onto the SiO2 layer by DC sputtering.
Step 3: Cr layer patterned to form a rear contact. 1 μm of a-Si:H p-i-n/ p-i-n/p-i-n triple junctions are deposited by dc glow-discharge decomposition of SiH4, diborane, methane for the p-layer, SiH4 for the i-layer, and SiH4, phosphine for the n-layer respectively.
Step 4: An anti reflective coating is deposited onto this stack and the stack is then mesa etched in 100% (CF4) plasma at 150W incident power. A 1200Å layer of indium tin oxide (ITO) is deposited using RF sputtering, and patterned using 5% hydrofluoric acid to form a series electrical interconnection between individual cells. The sample is then annealed at 220°C for 20 min. using a rapid thermal processor to decrease the sheet resistance of the ITO. 3.4.2 Applications, Challenges and the Future

Photovoltaic harvesters are mostly used in areas where the availability of sunlight is guaranteed such as marine locations and road signs. However, the efficiencies of these cells are relatively low and researchers are looking to refine solar cell materials and technology so as to increase the efficiency. By doing so, the area needed to collect a sufficient amount of energy from the sun can also be reduced.
A study conducted at the University of Florence, Italy, showed a new technology that exploited alternated electro-deposition of Cu, Sn and S to obtain CuxSnySz thin films. These materials are low in cost and have a higher conversion efficiency when used in solar cells. The main finding of this research is that Electrochemical Atomic Layer Epitaxy enables altering the order of deposition and the amount of cycles via a very simple process which gives control over the band gap and thus the amount of energy generated.

4. Conclusion

In conclusion, there are 4 basic methods that can be used to harvest energy from the ambient and the choice of which type to use depends on where the device will be used

Figure 11: Characteristics of various energy sources in the ambient and harvested power.
Figure 11 shows a summary the output power that could be obtained from environmental sources when using optimized devices built with the currently technology available. The table shows that energy harvesters can be used effectively when needed to generate power between 10uW to 1mW, which is typical of WSNs. The different modes of energy harvesting has been summarized in this paper. Despite there being many years of research into this subject, we are only at the tip of the ice berg as there is so much more to learn and to be improved on.
References:
[1] Harb, A. (2010). Energy harvesting - state of the art. Renewable Energy, 36, 2641-2654
[2] C.B. Williams, R.B. Yates, Analysis of a micro-electric generator for microsystems, Sensors and Actuators A 52 (1996) 8–11.
[3] Woodford, C. (2013, September 19). Piezoelectricity. Retrieved from http://www.explainthatstuff.com/piezoelectricity.html
[4] Molki, A. (2010). Simple demonstration of the Seebeck effect. Science Education Review, 9(3),
[5] Sniderman, D. (2012, January). MEMS vibrational micro power generation.
[6] Fang, H. B., Liu, J. Q., Xu, Z. Y., Dong, L., Wang, L., Chen, D., Cai, B. C., & Liu, Y. (2006). Fabrication and performance of mems-based piezoelectric power generator for vibration energy harvesting. Microelectronics Journal, 37(11), 1280-1284.
[7] R.K. Sood, Piezoelectric micro power generator (PMPG): A MEMS- based energy scavenger, MIT dissertation, 2003.
[8] Vullers, R. J. M. (2009). Micropower energy harvesting. Solid-State Electronics, 53(7), 684-693.
[9] Huesgen, T. (2007). Design and fabrication of mems thermoelectric generators with high temperature efficiency. Sensors and Actuators A: Physical, 145-146(2008), 423-429.
[10] Moser, A. (2012). Thermoelectric energy harvesting from transient ambient temperature gradients. Journal of Electronic Materials, 41(6), 1653-1661.
[11] Leonov, V. (2005). Thermoelectric mems generators as a power supply for a body area network . Solid-State Sensors, Actuators and Microsystems, 2005. Digest of Technical Papers. TRANSDUCERS '05. The 13th International Conference on, 1, 291-294.
[12] Shaijk. R. (2010). Challenges of energy harvesting. IMEC, 2010 [13] Ungan T, Reindl LM. Harvesting low ambient rf-sources for autonomous measurement systems. In: Proceedings of I2MTC 2008 – IEEE international instrumentation and measurement technology conference, Victoria, Vancouver Island, Canada; May 12–15, 2008.

[14] Dibin Zhu et al (2010) Meas. Sci. Technol. 21 022001 Strategies for increasing the operating frequency range of vibration energy harvesters: a review

[15] Chalasani, S. (2008). A survey of energy harvesting sources for embedded systems. In Southeastcon, 2008. IEEE (pp. 442 - 447). doi: 10.1109/SECON.2008.4494336
[16] Di Benedetto, F., Bencistà, I., Caporali, S., Cinotti, S., De Luca, A., Lavacchi, A., Vizza, F., Muniz Miranda, M., Foresti, M. L. and Innocenti, M. (2014), Electrodeposition of ternary CuxSnySz thin films for photovoltaic applications. Prog. Photovolt: Res. Appl., 22: 97–106. doi: 10.1002/pip.2386
[17] Honsberg, C. (n.d.). Band gap. Retrieved from http://pveducation.org/pvcdrom/pn-junction/band-gap

Similar Documents

Free Essay

A Love

...Tables and Figures Tables should be labeled and captioned above the table as "Table N," where N denotes the number of the table, and captioned. Material such as photographs, images, charts, and line-drawings should be labeled and captioned below the material as "Figure N" where N denotes the number of the figure, and captioned. Tables and Figures are numbered separately in series, 1….N. Captions for each should describe briefly, in neutral terms, the content of the table or figure. Quotations and Paraphrasing You should have very few, if any, quotations in your paper. Let us repeat that, VERY FEW QUOTATIONS. Quotations that constitute fewer than five lines in your paper should be set off with quotation marks [ “Lions roar” ] and be incorporated within the normal flow of your text. For material exceeding that length, omit the quotation marks and indent the quoted language one inch from your left-hand margin. Any quotation should be followed in parentheses by the source of the quotation. Mostly, you will paraphrase what you read, meaning that you put it in your own words. All your own words! Do not use a quotation with only one or two words changed. Doing this amounts to PLAGIARISM and will be treated as such!! Refer to the pdf at the following web site for additional useful information about avoiding plagiarism: http://sja.ucdavis.edu/files/plagiarism.pdf Citing the Scientific Literature EACH AND EVERY FACT drawn from a reference must be followed in the text by...

Words: 817 - Pages: 4

Free Essay

12345

...BUYBYBF FS FWEFWEWEFfgdsfg ggeragergsfsa fsfwf sfnn lglgleleggrrgegjrejgjrjrjrjrjrjgjjgjergjegjgjsdgdsfkgdfkgkTermPaperWarehouse.com - Free Term Papers, Essays and Research Documents The Research Paper Factory * Join Bottom of Form Factors Affecting The Academic Performance Of College Working Student Factors Affecting The Academic Performance Of Selected Working Student a researcher, the main purpose of the study is to know the factors that affect the academic performance of working students. In addition, this paper aims to provide... Save Paper * Factors Affect The Academic Performance Of Selected Working Student Chapter 1 The Problem And Its... the requirement in Marketing I. This is to certify that the Marketing Plan prepared by the following students: Beriña, Ivan Jan Erick C. Cuarez, Hazel D. Dulay... Save Paper * Significance Study Of Factors Affect The Academic Performance Of Selected Working Student easier access toinformation, that it motivated students to perform at a higher level, and that it providedcurrent information. In addition to these high-frequency... Save Paper * Factors Affect The Academic Performance Of Selected Working Student Submitted by: Bri Let's get physical Get down, get hard, get mean Let's get physical And beat that other team! Submitted by: Bri Hey, Hey Hey hey are you ready... Save Paper * Factors Affecting The Academic Performance Of Selected Working Student The Book Kate skimmed through, with her fingers, through all...

Words: 311 - Pages: 2

Free Essay

Sdaf

...National University Bachelor of Business Administration (Honours) or B.B.A. (Honours) Degree Department of Accounting, Management, Marketing, Finance & Banking Second Year Term Paper Guidelines: (1) Each Department shall form a Term Paper Committee consisting of all teachers of the Department, to monitor the overall supervision of the preparation of Term Papers. The Head of the Department shall be the ex-officio Chairman of the Committee. (2) One student shall submit three (3) copies of Term Paper, first copy for the Supervisor, second copy for Second Examiner and third copy for the Controller of Examination of the National University. (3) The Committee shall select a list of Term Paper Topics during the first month of starting the classes of the second year of BBA (Honours). The Term Paper Topic should be selected on an area only from the major subjects of a student at First Year or Second Year. The number of topics shall be at least ten (10) and shall not be more than 20 (twenty) in total. One Chapter Heading of a Major Subject may be customized for a topic of the Term Paper. (4) Term Paper shall be prepared in English by each student individually and every student shall be assigned under a Supervisor for preparing a Term Paper. (5) The Committee shall assign a Term Paper Topic randomly to the students and shall also select the Supervisor and the Second Examiner randomly from the teachers of the concerned Department. The students of a Department shall be primarily...

Words: 657 - Pages: 3

Free Essay

Essay

...users, mainly because they find code handling and scripts extremely confusing. Well, with some of the screenshots below you might get an idea of how to do it in very simple and easy steps. Once you have a Google account, you can go to (analytics.google.com). Here you will be greeted with three steps that you need to complete for setting your Google Analytics account. On clicking ‘Sign Up’ button you will land of this page where you are required to fill in all important details related to your website After filling in all the details when you click the ‘Submit’ button a page will appear in front of you that would be like this Once you are finished, you will click the ‘Get Tracking ID’ button a pop-up will appear with Google terms and conditions, which you have to agree to. Then you will get your GA Tracking code. This needs to be placed on all pages of your website. The installation depends on the nature of website. For example in a Wordpress site the framework has a specific area where header and footer scripts of GA code can be added. With the code placed on all pages of the site, tracking of visitors as well as other important dimensions will commence. 2. What are the 2-5 most important tools/features that beginning GA users should know? Why are these important? Online Assignment Help for...

Words: 3016 - Pages: 13

Free Essay

The ---

...TermPaperWarehouse.com - Free Term Papers, Essays and Research Documents The Research Paper Factory Join Search Browse Saved Papers Home Page » Science Example of Investigatory Project In: Science Example of Investigatory Project USING POTASSIUM CARBONATE AND SODIUM BORATE AS FIRE RETARDANT IN DIFFERENT KINDS OF CLOTH Team Category Cluster 2 Applied Science Charalin Mae P. Chavez Ashley D. Tumulak Khent Bernard F. Bensi Babag National High School (Science Class) table of contents Title Page ……………………………………………………… i Table of Contents ……………………………………………………… ii Abstract ……………………………………………………… iv Research Plan Research Materials ………………………………………………………1 Research Procedure ………………………………………………………1 Precautionary Measures ………………………………………………………2 Safety Measures ………………………………………………………3 Introduction Research Background ………………………………………………………4 Objectives of the Study ………………………………………………………5 Significance of the Study ………………………………………………………6 Scope and Limitations ………………………………………………………7 Definition of Terms ………………………………………………………8 Review of Related Literature ………………………………………………………9 Results and Discussion ………………………………………………………13 Findings ………………………………………………………14 Summary ………………………………………………………15 Conclusion ………………………………………………………15 Recommendations ………………………………………………………16 References / Bibliography ………………………………………………………17 Appendices ………………………………………………………18 Acknowledgement ………………………………………………………19 ABSTRACT The main aim of this study...

Words: 411 - Pages: 2

Free Essay

Adventures in Cheating

...in Cheating A guide to buying term papers online. Students, your semester is almost over. This fall, did you find yourself pulling many bong hits but few all-nighters? Absorbing much Schlitz but little Nietzsche? Attending Arizona State University? If the answer is yes to any or (especially) all these questions, you will no doubt be plagiarizing your term papers. Good for you—we're all short on time these days. Yes, it's ethically blah blah blah to cheat on a term paper blah. The question is: How do you do it right? For example, the chump move is to find some library book and copy big hunks out of it. No good: You still have to walk to the library, find a decent book, and link the hunks together with your own awful prose. Instead, why not just click on a term paper Web site and buy the whole damn paper already written by some smart dude? Que bella! Ah, but which site? I shopped at several online term paper stores to determine where best to spend your cheating dollar. After selecting papers on topics in history, psychology, and biology, I had each paper graded by one of my judges. These were: Slate writer David Greenberg, who teaches history at Columbia; my dad, who teaches psychology at the University of Rhode Island (sometimes smeared as the ASU of the East); and my girlfriend, who was a teaching assistant in biology at Duke (where she says cheating was quite common). So, which site wins for the best combination of price and paper quality? I compared free sites, sites...

Words: 1732 - Pages: 7

Premium Essay

Syllabus

...Stetson School of Business and Economics The Stetson School of Business and Economics (SSBE) promotes the advancement and integration of quality business education and practice. In support of Mercer University’s mission, the School provides undergraduate and graduate programs that are designed to enable, enhance, and expand professional careers, civic responsibility and lifelong learning. ACC 601 A22 Accounting Theory Fall 2012 Session II Tuesdays: 6:00 P.M. to 10:15 P.M. Professor: Julie Petherbridge Office Phone/Voice Mail: 678-547-6010 Office: 205 BE Bldg Email: petherbrid_j@mercer.edu Fax: (678) 547-6160 Office Hours: 3 - 6 pm Tuesdays and Thursdays and by appointment COURSE DESCRIPTION This course focuses on financial accounting theory, current pronouncements, problems of income determination, and accounting research and research methodology applied to accounting issues. COURSE OBJECTIVES This course discusses broader implications of financial accounting and examines critically accounting theories. It provides theoretical base for financial accounting and reporting in business relationships characterized by information asymmetries. Besides its theoretical orientation, the course discusses institutional structure and different reporting environments of financial accounting and standard setting. It also features considerable coverage of financial accounting literature. Students completing this class should be able to: • To understand...

Words: 1161 - Pages: 5

Free Essay

Hoho

...National University Bachelor of Business Administration (Honours) or B.B.A. (Honours) Degree Department of Accounting, Management, Marketing, Finance & Banking Second Year Term Paper Guidelines: (1) Each Department shall form a Term Paper Committee consisting of all teachers of the Department, to monitor the overall supervision of the preparation of Term Papers. The Head of the Department shall be the ex-officio Chairman of the Committee. (2) One student shall submit three (3) copies of Term Paper, first copy for the Supervisor, second copy for Second Examiner and third copy for the Controller of Examination of the National University. (3) The Committee shall select a list of Term Paper Topics during the first month of starting the classes of the second year of BBA (Honours). The Term Paper Topic should be selected on an area only from the major subjects of a student at First Year or Second Year. The number of topics shall be at least ten (10) and shall not be more than 20 (twenty) in total. One Chapter Heading of a Major Subject may be customized for a topic of the Term Paper. (4) Term Paper shall be prepared in English by each student individually and every student shall be assigned under a Supervisor for preparing a Term Paper. (5) The Committee shall assign a Term Paper Topic randomly to the students and shall also select the Supervisor and the Second Examiner randomly from the teachers of the concerned Department. The students of a Department shall be primarily allocated...

Words: 658 - Pages: 3

Premium Essay

Term Paper

...A term paper is a semester written project that can be in a form of either an essay or a structured research paper. Basically it intends to enhance or develop the skills of the students in the aspects of communication, resourcefulness and discipline. Now what are the parts of a term paper that you should know about? Let me give you the five basic parts necessary for this article. 1. The cover page is the first part of the term paper. Actually it does not contain anything about the topic you have selected. It is just a page that provides the title of your work as well as details about you as the writer. A standard term paper usually has a separate cover page before the main pages of the article. 2. The next part of a term paper is the introduction. This is integrated in the actual page structure of the project. You need to provide a background of the topic that you have written. In this paragraph, make sure that you provide details why the topic is important and what is to be expected in the contents of discussions. You also need to place the thesis statement at the introductory paragraph. 3. The third part of a term paper is the body. Actually you are not limited to using only one paragraph. Depending on the discussions of the topic, you can expand the number of body paragraphs indefinitely. Some research term papers for school will have to contain discussions like methodology, literature review or pictures and diagrams. But always make sure that the body can support the thesis...

Words: 352 - Pages: 2

Free Essay

How to Write Research Ppaper

...Chapter 1. How to Write an A+ Research Paper This Chapter outlines the logical steps to writing a good research paper. To achieve supreme excellence or perfection in anything you do, you need more than just the knowledge. Like the Olympic athlete aiming for the gold medal, you must have a positive attitude and the belief that you have the ability to achieve it. That is the real start to writing an A+ research paper. CONTENTS: STEP 1. CHOOSE A TOPIC STEP 2. FIND INFORMATION STEP 3. STATE YOUR THESIS STEP 4. MAKE A TENTATIVE OUTLINE STEP 5. ORGANIZE YOUR NOTES STEP 6. WRITE YOUR FIRST DRAFT STEP 7. REVISE YOUR OUTLINE AND DRAFT Checklist One Checklist Two STEP 8. TYPE FINAL PAPER STEP 1. CHOOSE A TOPIC Choose a topic which interests and challenges you. Your attitude towards the topic may well determine the amount of effort and enthusiasm you put into your research. Focus on a limited aspect, e.g. narrow it down from "Religion" to "World Religion" to "Buddhism". Obtain teacher approval for your topic before embarking on a full-scale research. If you are uncertain as to what is expected of you in completing the assignment or project, re-read your assignment sheet carefully or ASK your teacher. Select a subject you can manage. Avoid subjects that are too technical, learned, or specialized. Avoid topics that have only a very narrow range of source materials. STEP 2. FIND INFORMATION Surf the Net. For general or background information...

Words: 2333 - Pages: 10

Premium Essay

Business Communication

...VIETNAM NATIONAL UNIVERSITY IN HO CHI MINH CITY HCMC International University School of Business Administration Course Syllabus BUSINESS COMMUNICATION Fall 2013 1. Faculty information: 1.1. Instructor: Loc Do, PgD, MBA, PhD 1.2. Office: N.A. 1.3. Office Hours: upon request. * Contact: the best way to contact me is by email. Please give me at least 24 hours to respond to your email. * Cell phone: 0909260385 * Email: locbusiness@yahoo.com 2. Course Information 3.1. Course Title: Business Communication 3.2. Credits: 3 3.3. Prerequisite: N.A. 3. Course Objectives and Learning Outcomes 4.4. Objectives This course is designed to give students a comprehensive view of communication, its scope and importance in business, and the role of communication in establishing a favorable outside the firm environment, as well as an effective internal communications program. The various types of business communication media are covered. This course also develops an awareness of the importance of succinct written expression to modern business communication. Many of the assignments are to be keyboarded. 4.5. Learning Outcomes * Understand and demonstrate the use of basic and advanced proper writing techniques that today's technology demands, including anticipating audience reaction * Write effective and concise letters and memos * Prepare informal and formal reports * Proofread and edit copies...

Words: 1346 - Pages: 6

Premium Essay

Global Warming

...all your needs? We a the reiable choice of writers to do your homework You have to attend that event yet your assignment is tying u up from moving about with your social activities. Like many students, you might have found yourself in a dilemma faced with a hard task of writing your academic papers. You may have spend numerous hours planning and writing your homework and only end up with discouraging grades. Well, worry no more. Our company is one of the most recognized homework writing services. Here you are assured of an ideal homework that meets all your specifications and it is this facor that has eared us the trust of thousands of studens in universities all over the world seeking homework help. Homework writing service: Dissertation writing service: When the going gets tough, buy custom dissertation online from research paper experts  Phew! Finally, you have completed your coursework and now must write a dissertation? Unless you have written a multitude of formal research papers before this is not going to be amusing. Even to the best of us, writing a dissertation to completion is never a walk in the park. Far from the simple tasks of essay writing or even writing a term paper, the exercise is going to be draining, time consuming, and, if not well prepared or not sure of how to conduct research, analyze data, and present findings, one to forget quickly. There is no two ways about this. Writing a dissertation amounts to completely new exercise, as you now must embark...

Words: 1706 - Pages: 7

Premium Essay

Final Term Paper

...Unit 10 Research Paper Part 6: Final Draft of Research Paper Course Objectives and Learning Outcomes * Demonstrate mastery of the writing process, from invention to revision. * Apply principles of composition to evaluate the effectiveness of multiple rhetorical strategies. * Explain and employ the concepts of purpose, audience and tone in relation to compositions. * Locate, analyze, evaluate, and use information from a variety of sources, including the ITT Tech Virtual Library. * Formulate and execute a practical research plan. * Refine the research paper’s introduction and conclusion. * Revise and complete a final draft based on peer and instructor feedback. Assignment Requirements Use your research diary and the revised copy of your research paper to create your final draft. In your final draft, be sure to include: Introduction 1. Consider to whom you will be delivering this information. * If nothing really comes to mind, free-write about everything you know about your audience. 2. Overall, start broadly and narrow as you go. Consider your thesis as the target. * Other strategies also work well, but remember that the goal of an introduction is to help your reader understand why this information is important and/or interesting. 3. Decide which of the five introductory moves works best. * You may have to try a couple different methods here. Don’t be afraid to experiment with your writing. Talk it out with a...

Words: 1538 - Pages: 7

Free Essay

Term Paper

...How to Make  Term Papers Outline ?   A good term paper outline should have the following sequence and contents to write a term paper. Introduction Introduce the topic of your term paper about which you have to write the term paper and proceed to write thesis statement. Thesis statement Thesis statement is an essential part of any term paper. Develop a thesis statement which clearly states the point you are discussing. Body of the Term Paper The body of the term paper has all the points to discuss and support with favorable evidences, experiments or examples. Present the collected data in a way that supports the thesis statement. Conclusions It is the final part where you have to present all the results you got from the research and make suggestions for further development in the field. Bibliography It is the list of references of the sources of information. There are different formats of referencing the information resources such as APA, MLA, Harvard, etc. So use the one instructed by your supervisor. CONTENTS: STEP 1. CHOOSE A TOPIC STEP 2. FIND INFORMATION STEP 3. STATE YOUR THESIS STEP 4. MAKE A TENTATIVE OUTLINE STEP 5. ORGANIZE YOUR NOTES STEP 6. WRITE YOUR FIRST DRAFT STEP 7. REVISE YOUR OUTLINE AND DRAFT               Checklist One   Checklist Two STEP 8. TYPE FINAL PAPER STEP 1. CHOOSE A TOPIC Choose a topic which interests and challenges you. Your attitude towards the topic may well determine the amount of effort and...

Words: 2167 - Pages: 9

Free Essay

Term Paper

...WORDS TERMPAPER 250 WORDS TERM PAPER TERM PAPER TERMPAPER 250 WORDS TERMPAPER 250 WORDS TERM PAPER TERM PAPER TERMPAPER 250 WORDS TERMPAPER 250 WORDS TERM PAPER TERM PAPER TERMPAPER 250 WORDS TERMPAPER 250 WORDS TERM PAPER TERM PAPER TERMPAPER 250 WORDS TERMPAPER 250 WORDS TERM PAPER TERM PAPER TERMPAPER 250 WORDS TERMPAPER 250 WORDS TERM PAPER TERM PAPER TERMPAPER 250 WORDS TERMPAPER 250 WORDS TERM PAPER TERM PAPER TERMPAPER 250 WORDS TERMPAPER 250 WORDS TERM PAPER TERM PAPER TERMPAPER 250 WORDS TERMPAPER 250 WORDS TERM PAPER TERM PAPER TERMPAPER 250 WORDS TERMPAPER 250 WORDS TERM PAPER TERM PAPER TERMPAPER 250 WORDS TERMPAPER 250 WORDS TERM PAPER TERM PAPER TERMPAPER 250 WORDS TERMPAPER 250 WORDS TERM PAPER TERM PAPER TERMPAPER 250 WORDS TERMPAPER 250 WORDS TERM PAPER TERM PAPER TERMPAPER 250 WORDS TERMPAPER 250 WORDS TERM PAPER TERM PAPER TERMPAPER 250 WORDS TERMPAPER 250 WORDS TERM PAPER TERM PAPER TERMPAPER 250 WORDS TERMPAPER 250 WORDS TERM PAPER TERM PAPER TERMPAPER 250 WORDS TERMPAPER 250 WORDS TERM PAPER TERM PAPER TERMPAPER 250 WORDS TERMPAPER 250 WORDS TERM PAPER TERM PAPER TERMPAPER 250 WORDS TERMPAPER 250 WORDS TERM PAPER TERM PAPER TERMPAPER 250 WORDS TERMPAPER 250 WORDS TERM PAPER TERM PAPER TERMPAPER 250 WORDS TERMPAPER 250 WORDS TERM PAPER TERM PAPER TERMPAPER 250 WORDS TERMPAPER 250 WORDS TERM PAPER TERM PAPER TERMPAPER 250 WORDS TERMPAPER 250 WORDS TERM PAPER TERM PAPER TERMPAPER 250 WORDS TERMPAPER 250 WORDS TERM PAPER TERM PAPER TERMPAPER 250 WORDS TERMPAPER...

Words: 340 - Pages: 2