Top PDF DESIGN AND FABRICATION OF TWINROTOR UAV

A twin rotor-type UAV is a type of helicopter which is propelled by two rotors. The blades rotate in opposite directions and a tail rotor is not required in order to counter act the angular momentum of the propellers. As a coupled dynamical system, by altering the motor speed, the position is also changed. The system is under actuated and very dynamically unstable. In many situations it is desirable that the system is to be as small as possible to achieve large movements, being able to move both vertically and horizontally. Specific characteristics, such as vertical flight ability and flying at low speeds, allow the model to perform tasks which are difficult to implement through other mechanisms and structures. With demand of applications for this kind of aerial vehicle rapidly increasing, also increases the interest in research, both in industry and academics. Several studies are being conducted on the dynamics and describing methods to regulate their flight by adding automatic stability control through a diversity of hardware and software control schemes.

Shri Tapas Kumar Pal, born in October, 1976 at Kolkata, obtained his M.Sc degree in Physics with specialization in Microwaves from University of Calcutta in 1999. He has worked as a Senior Research Fellow and Senior Scientist at Centre of Advanced Study in Radiophysics & Electronics, University of Calcutta for a period of 2.5 years from Feb 2000 onwards. Later he worked as an Examiner of Patents & Designs at Patent Office, Kolkata till July 2005. Presently he is working as a Scientist ‘D’ at Research Centre Imarat, DRDO, Hyderabad. He is currently engaged in development of MMW Seekers and Sensors. His special interests are Design and Development of MMW IMPATT Diodes, Oscillators and Amplifiers and their computer simulations. He has also been pursuing Ph.D (Tech) Degree at Institute of Radiophysics & Electronics, University of Calcutta, on “Millimeter wave IMPATT Diodes and Oscillators”. He is a Life Member of IETE and Member of IEEE.

ABSTRACT: A remotely controlled airship was designed, fabricated and demonstrated within a tight timespan of under a month after receiving the go-ahead. The main design requirement for this airship was to be able to operate from a Helipad located at an altitude of 6,572 feet AMSL under ISA+20 deg.C. The images of the terrain below were recorded during the light and transmitted in real-time to a ground based system using an onboard telemetry system. The paper describes the methodology followed for sizing of the envelope and key components of the airship, and the  procedure followed for in-house fabrication and testing. The major issues that cropped up during the operation of the airship in harsh weather conditions of rain and mild snow, as well as at night, are also highlighted. The demonstration established the eficacy of remotely controlled airships for aerial photography and data collection by snow scientists.

For this filter design, microstrip line is a good transmission line due to advantages of light weight, planar structure, low cost, compact size and easy integration with other components on a single fabrication method. Conventional low frequency techniques for fabrication do not fit at these frequencies due to the very high losses associated. Although many recent advents of novel materials and fabrication techniques like Micro-Electro- Mechanical Systems (MEMS), Monolithic Microwave Integrated Circuit (MMIC), etc are available, because of easiness; thin microstrip film fabrication technique is preferred [1].

Depending on the piezoelectric deformation mode, this type of technology can be clas- sified into four types: squeeze, shear, push and bend. The squeeze mode was the first to be invented and the tubes with a diameter of about 1 mm are radially polarized [7]. When it is desired to have a droplet ejected, a short time voltage pulse is applied and the contraction of the transducer is made radially. The result is a smaller tube that squeezes the ink and a droplet is expelled. Push and bend modes have the same principle, in both the electric field is generated between the electrodes parallel to the polarization of the piezoelectric material. Applying a voltage to the piezoelectric plate results in a con- traction of the plate thereby causing the diaphragm to bend inwardly into the pressure chamber. This bending, once more, applies pressure on the fluid inside the chamber forcing the droplet to come out. In a similar way, in push mode is applied a voltage that expand the piezoelectric material towards the nozzle. The piezoelectric material push a thin diaphragm, to prevent undesirable interaction between the actuator and the ink, which pushes the ink through the orifice [7]. In a shear mode system, the electric field is designed to be perpendicular to the piezoelectric material. If the electric field is applied parallel to the poling field, then the piezoelectric material reacts in extension mode, i.e., the material lengthness in one dimension and shortness in the other. This was the principle to push and bend mode. But if the electric field is applied perpendicular to the poling field, the piezoelectric material reacts in a shear mode which allows a change in only one dimension. This is the main operation principle of print heads in a shear mode [12].

Abstract— Aviation technology is a revolutionary emerging field. Aeronautical engineering stands as the pillar towards space science. In this regard the developing countries are stepping forward to expand their aviation field although materials and technological constraints play a significant hindrance. In the application of aeronautical engineering, a project of fabricating a homebuilt aeroplane with minimum cost and with alternatives of advanced material and technology is a desire. This may stand out to be the future guide for many others in developing countries who wish to develop the skill of homebuilt aeroplanes while keeping all constraints away to maintain pace with rest of the world.

sion and tolerance problems. On the other hand, it is important that these connections are reversible for two sets of requirements: (1) to allow changes and maintenance during the system service life; and (2) to allow material reuse when the components are no longer useful for their original purpose. Hence it is useful to consider two types of reversible connec- tions. Type I joints can be disassembled at any mo- ment in the system service life while the latter type, Type II is only disassembled at the fabrication or de- construction stages. The latter has lower tolerances and better overall performance while the first type trades structural performance for ease of assembly on site. The types of joints attainable with a given fabrication or construction process dictate the possi- ble material assemblies and consequently the form of a construction system and its expressiveness. This ar- ticle reports our findings on possible alternatives for the design of the joint and for their fabrication with a 3 axis CNC Router. Several options are prototyped, and their mechanical behavior is analyzed using Fi- nite Element Analysis. Based on these findings we propose a possible partition wall construction system that meets the previously mentioned design princi- ples.

Quasi-static tests were made in accordance to the standards of ABNT NBR ISO 7206-04 e ABNT NBR ISO 7206-6, which give the specifications concerning the positioning of the stems for the tests. These specifications say how far the stem needs to be inserted into the setting, both to the respect of the depth and the angle, to represent how it would be placed in the human femur. According to the standard ABNT NBR ISO 7206-04, the angles must be from, α= 10˚ degrees and β = 9˚ degrees, with 1˚ (one degree) of tolerance in both cases, and the insertion of the stem, that is the distance between the center of the sphere to the surface where the setting is, there must be D=80 mm. For the tests in accordance with the standard ABNT NBR ISO 7206-6, the angles must be α=10º and β=9º, com 0.30º (zero point thirty degrees) and 1º (one degree) of tolerance respectively, and the level of insertion of the Figure 3. Fabrication process of the core: (a) Fiber impregnation

Developments in computational design methods and their integration with digital fabrication processes allow us to think of a customized construction paradigm (Naboni & Paoletti 2015). This new process strategy is especially suited to the renovation of buildings built with traditional construction techniques, a diversified corpus in which the interventions are surgical and non-standard. Insulation Cork Board (ICB) is a natural and renewable material which maintains most of the characteristics of raw cork: lightness, buoyancy, viscoelasticity, and improves some like low heat and sound conductivity and acts as a fire retardant (Gil 1998; Fortes et al. 2003; Pereira 2007). Moreover, as a result of its production process, which originates big size blocks, it’s better suited to architectural applications and, as Sousa (2010) demonstrates, appropriate for customization processes with CNC technologies (Figure 1). Wood derivatives like OSB (Oriented Strand Board) and plywood are also natural and renewable materials, which in turn have complementary mechanical properties to ICB, namely, higher mechanical strength. In this context, we foresee that a file-to-factory digital process (Varela et al. 2014) will have several advantages: higher quality and speed, without sacrificing scope or increasing cost (Kieran & Timberlake 2003).

One of the major problems faced by numerous sectors of industry is the excessive abrasion wear of parts of machines and equipment. This phenomenon is particularly evident in the extractive industry, tool-making industry, metallurgy, automotive applications and power engineering. High requirements imposed on modern advanced materials exposed during performance to the effect of loads – thermal, mechanical or chemical – force the industry people to look for new engineering solutions. Here, a very important role can play the technologies related with the fabrication of functional materials, the design of which requires a very precise determination of function that the final product is supposed to perform, as it is usually the product function that determines some specific properties the product should possess, e.g. mechanical, magnetic, acoustic, optical, electrical, chemical, or thermal. The phenomenon observed more and more frequently is that the functional materials are capable of offering the set of

“If  the  Theory  of  making  Telescopes  could  at  length  be  fully  brought  into  Practice,  yet  there   would   be   certain   bounds   beyond   which   telescopes   could   not   perform.   For   the   air   through   which   we   look   upon   the   stars,   is   in   a   perpetual   tremor;   as   may   be   seen   by   the   tremulous   motion   of   shadows   cast   from   high   towers,   and   by   the   twinkling   of   the   fix’d   stars.   But   these   stars   do   not   twinkle   when   viewed   through   telescopes   which   have   large   apertures.   For   the   rays  of  light  which  pass  through  divers  parts  of  the  aperture,  tremble  each  of  them  apart,  and   by   means   of   their   various   and   sometimes   contrary   tremors,   fall   at   one   and   the   same   time   upon  different  points  in  the  bottom  of  the  eye,  and  their  trembling  motions  are  too  quick  and   confused  to  be  perceived  severally.  And  all  these  illuminated  points  constitute  one  broad  lucid   point,   composed   of   those   many   trembling   points   confusedly   and   insensibly   mixed   with   one   another  by  very  short  and  swift  tremors,  and  thereby  cause  the  star  to  appear  broader  than   it   is,   and   without   any   trembling   of   the   whole.   Long   telescopes   may   cause   objects   to   appear   brighter   and   larger   than   short   ones   can   do,   but   they   cannot   be   so   formed   as   to   take   away   that  confusion  of  the  rays  which  arises  from  the  tremors  of  the  atmosphere.  The  only  remedy   is   a   most   serene   and   quiet   air,   such   as   may   perhaps   be   found   on   the   tops   of   the   highest   mountains  above  the  grosser  clouds.”  (NEWTON,  2007).  

This study aimed to formulate, characterize and evaluate the Gliclazide (GLZ) microcapsules prepared with sodium alginate, guar gum and pectin in different ratios by ionotropic-gelation method. The microcapsules were evaluated against different parameters such as particle size and shape, Carr’s index, Hausner’s ratio, rheological studies and drug release kinetics. Fourier Transform Infra Red (FTIR) and Differential Scanning Calorimetric (DSC) studies demonstrated the absence of any drug - polymers interaction. Promising characteristics were observed in rheological behavior and release kinetics. The size of microcapsules and percentage yield was in the range of 676 to 727 µm and 69 to 77%, respectively. Scanning electron micrographs revealed that microcapsules were discrete, spherical and free flowing. Entrapment efficiency and uniform drug release kinetics were some of the probable characteristics depicting the novel formulation design of Gliclazide microcapsules.

In the design and fabrication of many engineering structures and machines, vibrational analysis and dynamical response of structures like beams (or rods or shafts) are important factor to investigate in order to increase the performance of these structures. For the analysis of complex engineering struc- tures like bridges, tall buildings, vehicle guide-ways, huge cranes, turbines and compressor blades, beams can be used as simple model. The dynamical response of beams is governed by linear as well as nonlinear differential equations both in space and time. To study their behavior it is therefore important to design methods for the numerical solutions of these partial differential equations. In this respect, recently some approximate analytical techniques (see for instance, Barari et al., 2010; Bayat et al., 2010; Baghari et al., 2014; Jafari et al., 2014; Bayat et al., 2011;, Ganji, 2012; He, 1999; He, 2006; Khan et al., 2012; Liu and Gurram, 2009; Mirgolbabaei et al., 2010; Sfahani et al., 2011) as well as numerical methods by Lai et al. (2008) (see also, Boukhalfa et al., 2010; Da Silva

Este trabalho aplica tecnologia de fabricação aditiva para fabricar malhas anepécticas bidimensionais, compósitas e leves capazes de demonstrar propriedades auxéticas (Coeficiente de Poisson negativo (NPR)) em combinação com o comportamento de negativa expansão térmica (NTE), usando como materiais constituintes polímeros que não apresentam NTE. Cada malha, obtida pela variação da combinação de material ou do parâmetro de design, foi testada num banho de silicone aquecido para estudar os efeitos das diferentes combinações no coeficiente de expansão térmica (CTE). Foram tiradas fotografias em diferentes etapas do processo de aquecimento e foram analisadas para determinar o CTE de cada malha. Verificou-se que todas as malhas estudadas demonstraram uma combinação bem-sucedida dos comportamentos NPR e NTE, e foi revelado que existe a possibilidade de ajustar as malhas para ativarem o comportamento NTE dentro de uma faixa de temperatura escolhida. Para um caso extremo, um coeficiente de Poisson de -0.06, juntamente com um CTE de −1568  10 -6 (ºC -1 ) foi alcançado.

conventional engine with a different source of power. Thus conventional moulds and manufacturing processes need not be modified to specifically suit our requirements and more importantly existing engines can be converted to run on compressed air. Our project mainly involves design and fabrication of specific parts necessary for the functioning of our vehicle that runs on compressedair [1] , which prior to these modifications would be running on petrol. Hence the project is titled ―Design and Fabrication of a 50cc two wheeler that runs on compressed air‖.

The basic aim behind our project was to make an environmental friendly portable automobile which would be easy to handle by both the sexes and would emit 0% emission. We have used D.C motor as our main power source due to which there is no emission at all and also the problem of fuel consumption is solved. Also keeping in mind the parking problems now days, we decided to make a triscooter which can be folded easily, so after the use one can fold the triscooter and can carry it along with him/her. Our design allows users to easily transport the triscooter using less space when it is “folded” into a compact size. We have made this design with our own innovative ideas and by referring some books and websites .Our project is unique and no foldable triscooter is available in market till now. The versatility of a folding triscooter is also appropriate for air travel and inadequate storage and at places where bike theft is a significant concern.

microtubes. The method is based on repeated immersion of a macroporous silicon template into a liquid PZT precursor under a sub-atmospheric pressure. Upon 20 con- secutive vacuum iniltrations, tubes with an outer dia- meter of 2 μm, length of about 30 μm and wall thickness of 400 nm were achieved. The X-ray diffraction analysis and scanning electron microscopy were employed to conirm a formation of the perovskite phase and hollow structure of the crystallized PZT tubes. The as- synthesized microtubes were assembled, in the next step, from solution onto pre-patterned electrodes using AC dielectrophoresis. A promising aspect of this research is the possibility to quickly and simply create electrical connections to ferroelectric microtubes at ambient conditions, and thereby it allows for making an electrical testing structure for potential applications in high-storage memory capacitors and high-performance piezoelectric actuators and sensors. We examine and discuss the in- luence of a number of dielectrophoretic parameters in details and summarize that careful electrode design and low-frequency low-amplitude square wave signals will allow for arranging high aspect ratio ferroelectric microtube structures at designed positions on silicon wafers.

After making the pot according to requirement (i.e., fixing the pot height depending upon the furnace size as well as the crucible size), the coil is wrapped around the pot. The dimensions (such as the wire diameter and length) of the heating wire are determined specific to our furnace requirement and size. Here we have chosen to go with the APM grade KANTHAL which has the highest temperature range of heating i.e., about 1600 ⁰C in the whole KANTHAL family. The calculation through which we arrived at the conclusion of wire diameter and length is explained in the design section. After getting the wire we have to make it into a helical coil by wrapping and turning it around a thin rod in a lathe, and the ends are made into hooks so that they can be easily connected to the power supply. After that the coil that is obtained from above said process is wrapped around the pot in a helical manner leaving some of the wire at the ends along with the hooks. To fix the coil around the pot the top and bottom end of the coil is tied to the top and bottom of the pot respectively with GI wires and knotted with nose plies. For maintaining uniform heating around the pot equal distance is maintained between two consecutive lines of the helix around which the coil is wrapped and the gaps are filled with thin pieces of ceramic blankets. This avoids any type of contact between any two consecutive coil lines and hence avoids any chances of short circuit. The parts of the coil that we had left at the top and bottom of the coil is covered with small ceramic beads for insulation purpose.

The problems related to the quality of the business environment and underdeveloped institutions contributed to a weak relationship between FDIpc and GDPpc. A weak indirect relationship also exists between PIpc and the level of GDPpc. A strong indirect relationship between REMpc and GDPpc was also observed. The correlation analysis showed that GDPpc was directly and strongly related to CBCpc. The coefficients obtained for CBCpc are statistically significant and point to a direct relationship between GDPpc and CBCpc. The obtained coefficients have been dramatically declining since 2008. This shows that the effects of the global economic crisis have been felt since 2008 and that it is the question of the crucial year for the development of the real and financial markets of CEE-9 countries. Thus, the only statistically significant regressor coefficient is CBCpc, whose positive value points out that an increase in CBCpc leads to an increase in GDPpc. Bearing in mind the downward trend of CBCpc on this market over the past years, in addition to the requests for the diversification of the sources of finance, it is evident that CEE-9 must encourage other forms of capital inflow. Apart from strengthening the domestic deposit base, emphasis must be placed on improving the quality of the business environment and raising the level of competitiveness, thus increasing above all else the level of FDI. This would enable overcoming the problem related to the lack of domestic savings, but the positive effects of this form of capital inflow on economic growth and development, i.e. an increase in GDPpc would also be felt.

The year 1967 saw the formation of the EAC as the permanent tripartite commission for East African Co-operation. This union was short lived as it collapsed in 1977. Through mediation and various meetings the East African Community was once again considered in 1993, however full participation only began in 1996 when the Secretariat was launched in Tanzania (Deaton, 1999). The countries involved were Kenya, Uganda and Tanzania. A meeting to formally establish the EAC and to sign the treaty was held in Tanzania in 1999. Issues that came up at this EAC meeting was for the establishment of a treaty to ensure the understanding of foreign policy co-ordination (Morales, 2012) whereby there would be no tariff rates and to implement the 80% tariff reduction objective set out by the Common Market for Eastern and Southern Africa (COMESA), as well as to tackle how they can combine resources and fight terrorism in their region. At this meeting the admittance of Rwanda and Burundi into the EAC was postponed as it was argued by Tanzania that the joining criteria had not yet been established (Drummond and Ramirez, 2009).