Investigating Rates of Reactions Essay Example for Free

Investigating Rates of Reactions Essay Investigate which factors out of temperature, surface area and concentration speed up the reaction between magnesium and hydrochloric acid the most. Chemical reaction: Mg (s)+ 2HCI (aq)== MgCI2 (aq)+H2 (g) Prediction: I think the most effective factor to speed up the rate of reaction will be temperature, I say this because when the molecules are at a higher temperature they will have greater kinetics energy and move more rapidly, so they will collide more frequently and most importantly with greater energy. Then surface area will be second greatest effect, increasing the surface area of the solid increases the number of collisions between solid and particles in solutions. If we take into consideration a cube with each side 1cm long it has a total surface area of 6cm2, halve each of the cubes so that there are eight cubes each with 0. 5cm long sides and the total surface area has doubled to 12cm, now halve the size of these smaller cubes. Surface area of 1 cube, sides 1cm= 6 sides x (1cm x1cm) = 6cm2 Surface area of 8 cubes sides 0. 5cm= 8 sides x 6 sides x (0. 5 x 0. 5)=12cm2 Surface area of 64 cubes, sides 0. 25cm= 64 cubes x 6 sides x (0. 25 x 0. 25)= 24cm2 Having the average size of the particles in a given quantity of solid, doubles the surface area. So making a solid reactant in a lump form into powder considerably increases the surface area. Concentration will be the third greatest factor, which will speed up the rate of reaction. Any increase in concentration should also increase the rate of reaction; if there are more molecules present there will be more collisions. Increasing the number of collisions does not always increase the rate of reaction. What matters is the numbers of effective, effective collisions have to involve the relevant molecules, in the correct orientation, with energy at the least equal to the activation level. Equipment   Conical flask   Hydrochloric acid of 4 different molars (0. 1, 0. 5, 1, 2) Stop clock Basin of water   Bung with the tube   Magnesium   Measuring tube   Top pan balance Plan: Concentration Four different concentrations will be used. (0. 1, 0. 5, 1, 2) firstly I will use the 0.1 molar of hydrochloric, 6cm of magnesium in conjunction with the 15 ml of hydrochloric acid. When the bung is put into the conical flask the amount of gas given off can be read. I will leave the magnesium and the acid for 1 minute and I will check how much gas is given off every 10 seconds and I will record it. This will be done for all the other ranges of concentrations. Temperature I will be using 4 different temperatures (fridge 12oC, room 24oC, 50oC, 60oC). The high temperature acids will be placed in a water of their designated temperature. The other acids will be placed in their obvious places. The acid will be put in the conical flask with 6 cm of magnesium then the gas given off will be read and recorded as done previously for the concentration. Surface Area For surface I will be using 5 different lengths of magnesium ribbon, (6, 5, 2, 1, 0. 5cm) I will also be using 0. 06g of magnesium powder. Each measurement of magnesium will be used in conjunction with 15ml of hydrochloric acid. When both elements are put into the conical flask the gas given off will be read and record in the same fashion as the other tests. For each test I will do it twice to make sure my results are realiable. Fair test To ensure that I carry out a fair test I will make sure I will use the same amount of magnesium apart from when I am testing that particular variable. Also I will also use the same amount of hydrochloric acid, also I will use the same concentration apart from when Im testing that variable. I will also time each test for the same amount of time. Safety   Safety goggles worn at all times.   Precautions taken when dealing with acids.   Follow all the rules of the lab so that I can work efficiently alongside others when they are doing their experiments. Results  Concentration 2nd set of results Temperature  Fridge 4 Conclusion From doing this investigation I have successfully achieved my aim, my aim was to investigate the factors, which affect the rate of reaction. My prediction was also correct. For concentration the gas given off for o. 1 molar of hydrochloric acid was much less that what was given off for 2 molar. When powder was used for surface area ample amounts of gas was given off where as when 6cm was used not much was given off. When the acid was at a higher temperature more gas was given off, this hypothesis wasnt backed up with the results from the first test, which is why it was good that I repeated all the tests. Evaluation On a whole I thought I worked quite well, but the investigation could have been conducted in a better fashion. The particular method we used to collect the gas wasnt that effective. If a gas syringe in conjunction with a clamp stand was used our results would have been much better. I think doing the investigation twice was a good decision because doing this made it manifest that the first set of results werent as reliable, this is because when the first set of results were compared to the 2nd set of results they were quite different especially room temperature and 50oC. In the experiment the amount of gas given off for those specific temperatures were lower than the second experiment. Scientific knowledge proves that when the temperature is raised the rate of reaction will be faster. Also another thing I could of done was to do all experiments in the method we did to collect gas and also kept everything the same but the variable to change could have been the method in which we collect the gas. By doing this I could of seen which method to collect the gas would have been most effective. Show preview only The above preview is unformatted text This student written piece of work is one of many that can be found in our GCSE Patterns of Behaviour section.

Pest Detection on Leafs Using Robot and Processing Labview

Pest Detection on Leafs Using Robot and Processing Labview ABSTRACT: Recent century is a full of technology. None field cant remain without the use of the technology. Agriculture is one of those fields. Agriculture is the backbone of India. Most of the scientists are doing research to increase the cultivate of crops. But one problem still exist which is a major concern of the cultivation of crop and that is crop pests. Due to these problems, The cultivation decreases and hence all the farmers and in turn the country suffers from lack of cultivation of crop. With the recent advancement in image processing and similar related techniques, it is possible to develop an autonomous system for pest classification. Early detection of pest or the initial presence of a bio aggressor is a key-point for crop management. If we are able to detect it at the initial stage, we can prevent pest on leaves without spreading all over the field, which reduces the loss of crop and money. In recent years, the development of the robots in agriculture has agriculture introduced. These robots should be capable of working 24 hours a day, in all weather condition. So if we use robots instead of farmers for detecting the pests on leafs efficiently, we can reduce the loss of crop and money. I. INTRODUCTION Agriculture is the backbone of India. Most  of the scientists are doing research to increase the cultivity of crops. But one problem still exist which is a major concern of the cultivation of crop and that is crop pests. Due to these problems, the cultivation decreases and hence all the farmers and in turn the country suffers from  lack of cultivation of crop. Different types of pesticides are there in market which are used to avoid the damage to fruit and vegetable, but the amount of pesticides to be used is not known due to which the cost as well as the environmental pollution gets affected. A strong demand now exists in many countries for non-chemical control methods for pests or diseases. Greenhouses are considered as biophysical systems with inputs, outputs and control process loops. Most of these control loops are automatized (e.g., climate and irrigation control). However no automatic methods are available which precisely and periodically detect the pests on plants. In fact, in production conditions, periodically observes plants and search for pests. This manual method is too time consuming. Diagnosis is most difficult task to perform manually as it is a function of a number of parameters such as environment, nutrient, organism etc. With the recent advancement in image processing and similar related techniques, it is possible to develop an autonomous system for pest classification. Early detection of pest or the initial presence of a bio aggressor is a key- point for crop management. The detection of biological objects as small as such insects (dimensions are about 2mm) is a real challenge, especially when considering greenhouses dimensions (10- 100m long). For this purpose different measures are undertaken such as manual observation of plants. This method does not give accurate measures. Hence automatic detection is very much important for ea rly detection of pests. Hence we have to detect the pest at the earlier stage not to spread all over the field. If we are able to detect it at the initial stage, we can prevent pest on leafs without spreading all over the field, which reduces the loss of crop and money.  In recent years, the development of robots in agriculture has introduced. These robots should be capable of working 24 hours a day, in all weather conditions. So if we use robots instead of farmers for detecting the pests on leafs efficiently, we can reduce the loss of crop and money. II.  LITERATURE  SURVEY Recent papers are describing to detect  mainly pests like aphids, whiteflies, thrips, etc using various approaches suggesting the various implementation ways as illustrated and discussed below. [1] Proposed a cognitive vision system that combines image processing, learning and knowledge-based techniques. They only detect mature stage of white fly and count the number of flies on single leaflet. They used 180 images as test dataset .among this images they tested 162 images and each image having 0 to 5 whitefly pest. They calculate false negative rate (FNR) and false positive rate (FPR) for test images with no whiteflies (class 1), at least one white fly (class 2) and for whole test set. [2] Extend implementation of the image processing algorithms and techniques to detect pests in controlled environment like greenhouse. Three kinds of typical features including size, morphological feature (shape of boundary), and color components were considered and investigated to identify the three kinds of adult insects, whiteflies, aphids and trips. [3] Promote early pest detection in green houses based on video analysis. Their goal was to define a decision support system which handles a video camera data. They implemented algorithms for detection of only two bioagressors name as white flies and aphids. The system was able to detect low infestation stages by detecting eggs of white flies thus analyzing behavior of white flies. [4] Proposed pest detection system including four steps name as color conversion, segmentation, reduction in noise and counting whiteflies. A distinct algorithm name as relative difference in pixel intensities (RDI) was proposed  for detecting pest named as white fly affecting various leaves. The algorithm not only works for greenhouse based crops but also agricultural based crops as well. The algorithm was tested over 100 images of white fly pest with an accuracy of 96%. [5] Proposed a new method of pest detection and positioning based on binocular stereo to get the location information of pest, which was used for guiding the robot to spray the pesticides automatically.[14] introduced contextual parameter tuning for adaptive image segmentation, that allows to efficiently tune algorithm parameters with respect to variations in leaf color and contrast. III.EXISTING  SYSTEM In earlier days in order to detect the pest  on leafs they used early pest detection in green houses based on video analysis. Their goal was to define a decision support system which handles a video camera data. They implemented algorithms for detection of only two bioagressors name as white flies and aphids. The system was able to detect low infestation stages by detecting eggs of white flies thus analyzing behavior of white flies. But this project has many limitations like it is time consuming process and also the output will not get accurately. So in order to eliminate these limitations ,we are going to proposed a system named pest detection on leafs by using robot and processing in LabVIEW. IV.PROPOSED  SYSTEM In this proposed system we are making  use of robots in order to take the live images from field section to monitoring section. The images taken by the robot processed and the type of disease is displayed accurately. By using this project we can get the output accurately and the type of disease. As we are making use of LabVIEW (Laboratory Virtual Instrumentation Engineering Workbench) software ,in this software instead of text there are making use of icons in order to create the programs. compared to the other softwares this software as many advantages like it will not show any errors at the time of executing the program, whereas other softwares even a small error is there means we will not get the output showing there is some errors, it eliminates the limitations in the existing system. Once you taken the image and create the class mentioning the type of samples in LabVIEW, definitely we will get the output mentioning the type of diseases. Workload on farmers is minimized by using these type of system. By making a track for robot it will be worked properly in slippery and unequal surfaces. If we use chain instead of wheels in the field, robot can work more effectively on unequal surface of the field. Farmers dont have to go in the field because robots do their work properly and effectively. Time consumed by the robots for detecting the pest on leafs is less than mankind, which can work efficiently. Fig 1:Block Diagram V.WORKING In block diagram we are using the web camera in order to take the live pictures from field section to the monitoring section. We are using high definition web camera model number (jil-2247).This web camera takes the images of affected leaf which are caused due to pests. Generally we prefer this type of web camera because it has high flexibly, as well the cost of this type of web camera is very less. It will send  live pictures from field section to monitoring section up to 10 meters distance. We are using wired web camera and this web camera is connected to system through USB cable. This web camera is generally monitored through the system. Next we are using Arduino UNO. The Arduino Uno is a Microcontroller board based on the ATmega328 (datasheet).it has 14 digital input/output pins(of which 6 can be used as PWM outputs),6 Analog inputs,16 MHZ crystal oscillator , a USB connection , a power jack , an ICSP header , and a reset button. In this project we are making use of only 4 digital input/output pins (i.e. pin nos 8, 9, 10, 11), 5v in and Ground pin. These 4 digital pins acts as output pins and also we are making use of 5v output pin as well as ground Pin. Remaining pins we are not using in this project. These 4pins are connected to 4 relays . Relay is nothing more than a switch. A Relay is an electromechanical switch used for one or more of the four (4) purposes 1. To turn something ON. 2. To turn something or disable something. 3. To change the polarity of a wire. 4. To increase the current supply of a wire. In this project we are using four (4) relays 1. for moving forward 2. for moving backward 3. for moving left side 4. for moving right side The main use of these four relays is to move the robot either forward, backward, left side, right side. Based on our request, the particular relay will be on and move in particular direction. These four relays are connected to the two dc motors. In order to work the dc motors we need power supply, so we are using 5v battery. Based on our request the particular relay will be on and this relay will be connected to dc motors and move in a particular direction. Lastly this dc motors are connected to the wheels to rotate. Instead of wheels we can use chains ,this chains can move in even in uneven flat surfaces. This robot take the live pictures from field section to monitoring section without the use of human effort and it will finds whether the leaf had caused marks and based on the marks it will intimate the type of disease. VI.  SOFTWARE  REQUIREMENTS The following are the software requirements used  in this project i. Virtual instrumentation ii. LabVIEW Virtualinstrumentation Virtual Instrumentation is the use of  customizable software and modular measurement hardware to create user-defined measurement systems, called virtual instruments. The concept of a synthetic instrument is a subset of the virtual instrument concept. A synthetic instrument is a kind of virtual instrument that is purely software defined. A synthetic instrument performs a specific synthesis, analysis, or measurement function on completely generic, measurement agnostic hardware. Virtual instruments can still have measurement specific hardware, and tend to emphasize modular hardware approaches that facilitate this specificity. Hardware supporting synthetic instruments is by definition not specific to the measurement, nor is it necessarily (or usually) modular. Leveraging commercially available technologies, such as the PC and the analog to digital converter, virtual instrumentation has grown significantly since its inception in the late  1970s. Additionally, software packages like National Instruments Lab VIEW and other graphical programming languages helped grow adoption by making it easier for non- programmers to develop systems. LabVIEW Lab VIEW (short for Laboratory Virtual  Instrumentation Engineering Workbench) is a platform and development environment for a visual programming language from National Instruments. Originally released for the Apple Macintosh in 1986, Lab VIEW is commonly used for data acquisition, instrument control, and industrial automation on a variety of platforms including Microsoft Windows, various flavors of  UNIX, Linux, and Mac OS. The programming language used in Lab VIEW, is a dataflow language. Execution is determined by the structure of a graphical block diagram. LabVIEW programs are called virtual instruments (VIs).Controls are inputs and indicators are outputs. Each VI contains three main parts: a. Front panel How the user interacts with the VI b. Block diagram The code that controls the program In LabVIEW, you build a user interface by using a set of tools and objects. The user interface is known as the front panel. You then add code using graphical representations of functions to control the front panel objects. The block diagram contains this code. If organized properly, the block diagram resembles a flowchart. VII.  SCHEMATIC  DIAGRAMS  IN LAB  VIEW Front  Panel: When you have created a new VI or  selected an existing VI, the Front Panel and the Block Diagram for that specific VI will appear as shown in below figure In LabVIEW, you build a user interface, or front panel, with controls and indicators. Controls are knobs, push buttons, dials, and other input devices. Indicators are graphs, LEDs, and other displays. You build the front panel with controls and indicators, which are the interactive input and output terminals of the VI, respectively. Controls are knobs, push buttons, dials, and other input devices. Indicators are graphs, LEDs, and other displays. Controls simulate instrument input devices and supply data to the block diagram of the VI. Indicators simulate instrument output devices and display data the block diagram acquires or generates. Fig 2: Front Panel VIII.  BLOCK  DIAGRAM After you build the user interface, you add  code using VIs and structures to control the front panel objects. The block diagram contains this code. In some ways, the block diagram resembles a flowchart. After you build the front panel, you add code using graphical representations of functions to control the front panel objects. The block diagram contains this graphical source code. Front panel objects appear as terminals, on the block diagram. Block diagram objects include terminals, subVIs, functions, constants, structures, and wires, which transfer data among other block diagram objects. It will accompany the program for the front panel which is shown in below figure Fig 3: Block Diagram IX. WORKING Vision  Acquisition In order to detect the pest in leafs, first we have to acquire the image (i.e. take the image of any one leaf in the field).for taking the image of the leafs we require one web camera. This web camera sends live picture from field section to the monitoring section. The below figure shows the image of the affected leaf which was taken from field Fig4:  Acquiring  the  image  of the  affected leaf Vision  Assistant After acquiring the image of the  affected leaf, assist the image (i.e. mentioning the type of the disease).create a class mentioning the type of disease and take the different samples of the image and store these in particular class. The below figures shows how to create a class, the samples of the different classes and also the samples of the affected leafs created in a particular in a particular class is as shown below Fig 5: a class of the affected leaf Fig 6: Samples of the affected leaf RobotControl After creating a class and storing the samples of the affected leaf in that particular class, take photo of the another leaf which was affected by same pest in another field with the help of robot by moving either forward, backward, left side, right-side in front panel. The below figures represents the field section and monitoring section, photo taken in front panel Fig 7:Image taken with the help of robot Fig 8: Monitoring section and Field section RESULTCONCLUSION By using this project we can detect the pest on affected leafs and also we can detect two or more diseases in one particular leaf. after taking the image in front panel ,it will be displayed on the screen as image is detected and the type of disease is:.the below figure represents the result of the affected leaf mentioning whether the disease is detected or not. Figure represents the image taken for the affected leaf with the help of robot and figure represents the output of the image whether the leaf is detected or not: and also the type of disease is as mentioned in the figure INPUT: Fig 9: Image taken with the help of robot OUTPUT Fig10: screenshot showing the disease of the affected leaf We are taking the image of the affected leaf with the help of web camera using robot by moving either left side, right side, backward, downward and after processing it finds whether the disease is detected, if it is detected the type of disease is displayed on the screen. CONCLUSIONFUTURESCOPE Future scope of this type of robots are  very bright because it is very useful in agriculture and reduce the workload. It reduce the time consumed in spraying the pesticide liquid and works very effectively. It will help the farmers to do work in any season and conditions. It will reduce the danger for the farmers from different breathing and physical problems. This type of robots are being used in bicontrol of avocao posttharvest diseases. This type of robots are used for managing diseases in greenhouse crops as well as many other crops. This type of robots are also used in the  fields to detect the fruit is ripen or not and also used for many other purposes REFERENCES [1]. P. Boissard, V. Martin, S. Moisan A  Cognitive Vision Approach to Early Pest Detection in Greenhouse Crops Computer and Electronics in Agriculture Journal,  62(2):83-93, April 2008. [2]. J. Cho, J. Choi Automatic identification ofwhiteflies, aphids and thrips in greenhouse based on image analysis International journal of mathematics and computers in simulation March 27,2007. [3]. Sanjay B. Patil, Dr. Shrikant K. Bodhe Leaf disease severity measurement using image Processing International Journal of Engineering and Technology Vol.3 (5),  2011, 297-301. [4]. M. T. Maliappis, K. P. Ferentinos, H. C.  Passam And A. B. Sideridis [2008] Gims: A Web based GreenhouseIntelligent Management System,World Journal of AGRICLTURAL Sciences 4(5):640-647. [5]. C. Bauch and T. Rath, Prototype of a Vision Based System for Measurements of White Fly Infestation,Institute of Horticultural and Biosystems Engineering, University of Hannover. [6]. Ganesh Bhadane, Sapana Sharma and Vijay B. Nerkar, Early Pest Identification in Agricultural Crops using Image Processing Techniques, International Journal of Electrical, Electronics and Computer Engineering 2(2): 7782(2013). [7]. Presents an automatic method for classification of the main agents that cause damages to soybean leaflets,i.e., beetles and caterpillars using SVM classifier.[12] proposed Back propagation neural network for recognition of leaves, diseases, pests.

Advantage Of Star Topology

Advantage Of Star Topology Star Topology: In a typical star topology, all computers/ stations are connected to a central device, usually a switch. They are connected to this central device via cable segments. Such cable segments are Unshielded Twisted Pair (UTP) and Shielded Twisted Pair, as well as, fibre optic cabling. http://www.inetdaemon.com/img/topology_star.gif Advantage of star topology: With the star topology, if one cable of device goes down, the rest of the network is not affected (fault tolerance). Disadvantage of star topology: However, because management of communication is centralized, if the main switch or hub goes down the whole network goes down. Extended Star Topology: As the name implies, it is a bit more advanced than the typical star topology. In this topology, there is also a central device, usually a switch, in the middle of the network. However, instead of computers being directly connected to this central switch, other switches or hubs are connected to its ports. Computers and other peripherals are then connected to these switches or hubs, forming other stars; hence an extended star is the final result. http://t0.gstatic.com/images?q=tbn:O2WYXsb8K_NPNM:http://upload.wikimedia.org/wikipedia/ro/b/b5/Extended_star_topology.png Advantage of extended star topology: As a result of there being a central switch, it is easy to locate and troubleshoot any problematic areas. Disadvantage of extended star topology: Again, because of the use of the centralized switch, once the switch goes down it creates problems for the entire network. Ring Topology: In this particular network topology, each computer/ station is directly connected to the next one in line and ends at the very first computer/ station, resulting in a circular formation/ arrangement of the cables. Each computer has the responsibility of retransmitting communication messages. The communication messages all travel in one direction and as a result of having no end in the circular formation, there is no real need for termination. http://www.inetdaemon.com/img/topology_ring.gif Advantage of ring topology: Due to the topologys structure, there is no need for terminators. Disadvantage of ring topology: Any break or fault in the cable can disrupt communications. Bus/ Linear-Bus Topology: This structure utilizes a single cable segment which connects all the computers in a single straight line. All computers in this topology share this single cable segment and as a result a terminator is needed. This is due to the fact that the signals need to be absorbed as they reach the end of the bus in order to free the network for fresh and newer communications. http://www.inetdaemon.com/img/topology_bus.png Advantage of bus topology: This is an inexpensive topology to install. Disadvantage of bus topology: With all the devices sharing the same backbone cable, communication speeds are lowered. Tree Topology: Logically, this is an extension to the less complex bus topology. www.networkdictionary.com states that The transmission medium is a branching cable with no closed loops. The tree layout begins at a point called the head-end, where one or more cables start, and each of these may have branches. The branches in turn may have additional branches to allow quite complex layouts. It is often referred to as the star- bus topology. Available from: www.networkdictionary.com/networking/lanat.php [Date accessed: October 24th 2009] graphics/04fig11.gif Advantage of tree topology: This topology allows point to point wiring for individual sectors. Disadvantage of tree topology: A break in the main backbone cable will affect the entire network. Mesh Topology: In the mesh topology, each device in a network is connected to every other device in the particular network. The mesh topology is typically used to connect several LANs together to create a WAN (it is more WAN based technology) e.g. the internet is a perfect example of a mesh topology. http://www.google.tt/images?q=tbn:MKaJ7Z8cc3BUJM::www.erealmedia.com/cms102/uploads/NetworkingPrinciples/Chapter1/1_23_MeshTopology.jpgt=1h=196w=176usg=__QGrcgQACaPCnhXDPW-hE9X5a-Rw= Advantage of mesh topology: Due to the fact that all devices are interconnected to each other, there are various alternate routes, which improve fault tolerance. Disadvantage of mesh topology: Managing and troubleshooting this architecture is very difficult, complex and expensive. 1.2.0 Advantages and Disadvantages of LAN media The media used in a typical LAN (Local Area Network) are Coaxial cables, Twisted-pair cables (Unshielded and shielded twisted pair) and Fibre Optic cables. 1.2.1 Advantages of Coaxial cables: Appropriate for Broadband system: Coaxial cables possess adequate ranges of frequency that can support several network channels and as a result of such capability, allows for much greater throughput. Better bandwidth: Compared to twisted pair cables, coaxial offers a better bandwidth system wide, as well as, better bandwidth for each network channel. As a result of this, there is support for a diverse range of service. Network functionalities such as data, voice, video and even multimedia can profit from the improved capacity. An even better spacing between amplifiers: Due to the cable shielding possessed by coaxial, there is a reduction in noise and crosstalk, thereby allowing amplifiers to be spaced farther apart. Lower error rate: Noise resistance is enhanced because the inner conductor is in a wire mesh and coaxial has lesser error rates. Better channel capacity: Extensive capacity is offered from each of the several channels. Disadvantages of Coaxial cables: Installation can be expensive Prone to damage from lightning strikes: People residing in areas, in which lightning strikes frequently occur, must be cautious. If the lightning is conducted by a coaxial, chances are that the equipment connected to the end of that particular coaxial, may be fried. Noise: The path of return has noise exertion and the end apparatus requires additional aptitude to deal with error control. Deployment architecture problems: The bus topology in which the coaxial is set up is vulnerable to noise, clogging and security can be jeopardized. Bidirectional (two-way) upgrade is required: In countries where there is a history of cable television, these systems are designed and built for broadcasting, not interactive communications. For a service provider to offer a subscriber any form of two-way communication services, the current network system needs to be upgraded to a Bidirectional system. 1.2.2 Advantages of Twisted pair cables: The cost of installing twisted pair on site is low High availability: Billions telephone subscriber lines established on twisted-pair have been set up and because it is already in the ground, the telecommunication companies will use it. Low cost for local moves, additions and changes in places: Individuals can swap twisted-pair terminating in a modular plug with another jack. This can be done without a service technician, given that the wiring is already in place. Disadvantages of Twisted pair cables: Frequency spectrum is limited: The total serviceable frequency spectrum of is about 1MHz. High error rates: It is extremely susceptible to interferences in signal communications, caused by EMI (Electromagnetic Interference) or RFI (Radio Frequency Interference). Data rates are limited: The longer the distance the signal travels over cable, the lower the data rate will be. At 30 feet (100m), twisted-pair is capable of carrying 100Mbps. At 3.5 miles (5.5km), the data rate can drop to 2Mbps or possibly less. Short distances are required between repeaters. 1.2.3 Advantages of Fibre Optic cables: Fibre optic cables have higher bandwidth compared to other mediums. It is impossible to tap into fibre optic cables. This makes them much more secure compared to other mediums. One can add equipment to provide extra capability over a fibre without having to change it. No electricity passes through the cables what so ever, and as a result they do not conduct lightning strikes They are light weight Disadvantages of Fibre Optic cables: They are more fragile compared to other mediums. Installation of the cables is quite expensive. Termination of fibre optic cables is quite complex and requires special tools 1.3.0 Recommendation After much investigation of the various LAN topologies and media, I have gathered comprehensive information and have come to a conclusion which topology and media type should be used. With respects to the LAN topology, I strongly recommend that the extended star topology be implemented. The extended star offers fault tolerance in that, if failure in one cable or device occurs, it doesnt pose as a threat to the rest of the network. If at all there are problems with particular cables or devices, the task of locating them is quite easy. Management is centralized due to the use of the centralized switch and it is easy to add devices as the network expands. Also, it can be upgraded for faster speeds and better performance, not to mention that it is the most widely used, so much support is available. Such a LAN topology proves to be quite costly but with all its benefits it is worth the expense. With regards to network media, if the extended star LAN topology is to be in use, the unshielded twisted-pair cables are a suitable medium. The installation costs are low and in addition, any changes or additions are cheaper compared to other media types. Furthermore, telecommunication companies will use subscriber lines that already exist, so there is no need for additional costs of running lines. Bibliography K. Wilson Jarrett and L. Goleniewski, (Oct. 12th, 2007), Traditional Transmission Media for Networking and Telecommunications. (Coaxial Cable) www.informit.com/articles/article.aspx?p=683070seqNum=2# [Date accessed: October 24th 2009] K. Wilson Jarrett and L. Goleniewski, (Oct. 12th, 2007), Traditional Transmission Media for Networking and Telecommunications. (Twisted-Pair) http://www.informit.com/articles/article.aspx?p=683070 [Date accessed: October 24th 2009] K. Wilson Jarrett and L. Goleniewski, (Oct. 12th, 2007), Traditional Transmission Media for Networking and Telecommunications. (Fibre Optics) http://www.informit.com/articles/article.aspx?p=683070seqNum=5 [Date accessed: October 24th 2009] Network Dictionary, (2004-2010), LAN Architectures and Topologies: Bus, Star, Ring and Tree. www.networkdictionary.com/networking/lanat.php [Date accessed: October 24th 2009] Task 2 a) 2.1.0 Internet services required 2.1.1 E mail: The abbreviation for electronic mail; this is a system of exchanging information/ messages digitally via the internet. 2.1.2 Voice/VoIP: The abbreviation for Voice Over internet Protocol; this is a system used in telecommunications for the transmission of voice traffic/phone calls over any network based on IP (Internet Protocol) e.g. the internet. 2.1.3 FTP: The abbreviation for File Transfer Protocol; this is the TCP/IP standard used for the transferring of files from one computer to another. 2.1.4 TELNET: This is the TCP/IP standard used for remote terminal services. It allows users at one site to transparently interact with a remote system or network at another site, whilst appearing as a local terminal. 2.1.5 Video communication: J. Wilcox Pg.3 states, Video communication is real-time exchange of digitized video images and sounds between conference participants at two or more separate sites. 2.2.0 Required connection speeds 2.3.1 With regards to Audio and Data communication, 64 Kbits/s is sufficient enough for use of this service. In the case of Video communication, bandwidth of 2Mbits/s or more may be required for proper transmission. Furthermore, www.whichvoip.com states VoIP requires anywhere from about 24Kbits/s to about 90Kbits/s. Overall, once serviced with an appropriate broadband package, these requirements will be addressed. Available from: http://www.whichvoip.com/voip/speed_test/ppspeed.html [Date accessed: October 27th 2009] 2.3.0 Internet Service Providers (ISPs) In Trinidad, there are various internet service providers from which one can subscribe for broadband services. Blink, Flow, and Lisa Communications are such ISPs. 2.3.1 Blink Packages 2.3.2 Flow Packages 2.3.3 Lisa communications 2.4.0 Recommendation After investigations on ISPs in Trinidad regarding their services and prices offered, I have seen favourable packages with one particular ISP, Flow. Flow offers its customers bandwidth speeds ranging from 512k/1Mbps to 3Mbps/9Mbps. Also they provide free static IP addresses and email addresses, and the number of IP email addresses one receives depends on the package one chooses. The packages are as follows:

Literary elements used by poe :: essays research papers

Literary Elements in Poe’s Writing   Ã‚  Ã‚  Ã‚  Ã‚  In the writings of great authors it is easy to pick out the literary elements used by them. Edgar Allan Poe is one of these authors. He makes use of the same literary elements in many of his stories. Three of the most used literary elements are irony, antagonists and foreshadowing.   Ã‚  Ã‚  Ã‚  Ã‚  Irony is used very often by Poe. Irony is when something occurs that is the exact opposite of how it should be or seem. Irony varies in that it may be displayed through someone’s actions or an ironic happening. An example of irony in someone’s action are in the Cask of Amontillado is when Montressor repeatedly seems concerned for Fortunato’s health, even though his real intentions are to kill him. It also may be considered ironic that Poe named the enemy of Monstressor, Fortunato. Being that Fortunato means fortunate or lucky in Italian, it is ironic that he is very unlucky in that he his buried alive in a wall.   Ã‚  Ã‚  Ã‚  Ã‚  The Antagonist is also a literary element used by Poe is this story. We see how Forunato so ignorantly and thoughtlessly antagonized the questionably insane Montressor. The consequence for this antagonist was death by dehydration and starvation.   Ã‚  Ã‚  Ã‚  Ã‚  One of the most common literary elements used by Poe throughout many of his works is foreshadowing. Poe loved foreshadowing what is to come as much as he can. We see him often use little things to foreshadow. Such as, the infamous raven, or the dichromatic beating of the heart within a dead man buried in the floor. In the Cask of Amontillado, we see foreshadowing in the speech of Monstressor and Fortunato. When Fortunato states, â€Å"I shall not die of a mere cough†, Monstressor enthusiastically agrees with him.

College Admissions Essay: A Life Changing Experience :: College Admissions Essays

A Life Changing Experience    The experience of the APEC Youth Science festival was incredible. It has had an enormous impact on me in many ways, changing the way I look at the world and connecting me with people and events far beyond my formerly limited experience. I am extremely glad to have had this opportunity. It was a wonderful experience on multiple levels. It challenged me and expanded me intellectually and socially. I feel that this experience has had an immense impact on me.    Through this program I had first-hand access to some of the brightest young minds in both the United States and the world. The sharing among students of ideas and experiences in science, and in other areas as well, was enlightening. I felt like I had the chance to absorb knowledge from those around me. This environment spread beyond the students and also included the faculty and speakers. We had access to incredible faculty who were able to give much to the experience and share their own science insights. The program also brought in speakers and other science professionals from around the world who were at the top of their respective fields. This festival gave me real access to the movers and shakers of the science world, an experience beyond any available to me anywhere else.    The most fascinating aspect of this experience, for me, was the exposure to new cultures. This includes the twist culture puts on science. I found huge difference in the viewpoints of many cultures towards science related issues surprising. For instance many cultures had vastly different ways of looking at the forthcoming issues surrounding the implications of genetic engineering. The Asian and American cultures were very different in many work habit areas as well. There was an interesting group dynamic as culturally mixed groups strove to collectively complete group projects. The cultural sharing in science went beyond how questions were answered to how they were asked to which questions were most important and even which questions were addressed. while observing the cultural spin on science and work habits was an interesting pastime, the true wonder was cultural sharing on a greater scale.    This program exposed me to Asian cultures in a way I had never thought possible. Living in an Asian country, even for only a week, and being mixed with students from around the world brought me face to face with cultures I had never before truly experienced.

The Reluctant Fundamentalist

How does Hamid employ symbolism throughout the novel? Is his use of symbolism effective? What is lost and gained through the use of symbolism? The Reluctant Fundamentalist is a novel in which an American immigrant Changez is living a dream with a great job, money, and the â€Å"regal† Erica by his side. However after the 9/11 attacks Changez’s perception on America shifted, he was forced to question where his allegence lies and this developed into contempt for America.If you read The Reluctant Fundamentalist by Mohsin Hamid, and fail to dig below to the surface of the text then the novel will hold an entirely different meaning to you. Hamid used heavy sybolism to convey meanings and themes that are better not said outright, and overall altered the impression the novel leaft. While reading The Reluctant Fundamentalist it became apperant that Changez’s love interest Erica symbolized America. Besides the obvious that Erica is the last five letters of America, there were multiple parallels in the story Hamid built for Erica and the way he portrayed America.When Changez first met Erica he says, â€Å"She had a presence †¦a naturalist would likely have compared her to a lioness: strong, sleek, and invariably surrounded by her pride†(22). Changez also comments of the pride America shows with, â€Å"stickers of flags adorned windshields and windows; large flags fluttered from buildings. They all seemed to proclaim: We are America†¦the mightiest civilization the world has ever known. †(79). Akin to America after 9/11, Erica seemed to be, â€Å"utterly detached, lost in a world of her own†¦ she was struggling against a current that pulled her within herself†(86).Similarly after 9/11 Changez felt that America, â€Å"retreated into myths of your own difference, assumptions of your own superiority†(168). The grief that Erica felt over the loss of Chris was representative of the grief America felt after 9/11 and how that prevented both Erica and America from moving on and accepting Changez. When Changez goes to see Erica at her clinic he is told by a nurse that, â€Å"It did not matter that the person Erica was in love with was deceased; for Erica he was alive enough, and that was the problem. †(133) America, too, was increasingly giving itself over to a dangerous nostalgia,† he claimed that he, â€Å"had always thought of America as a nation that looked forward; for the first time I was stuck by its determination to look back. †(115) The grief that Erica felt over the loss of Chris was representative of the grief America felt after 9/11 and how that prevented both Erica and America from moving on and accepting Changez. When Changez goes to see Erica at her clinic he is told by a nurse that, â€Å"It did not matter that the person Erica was in love with was deceased; for Erica he was alive enough, and that was the problem. (133) If Erica represents America and their in ability to move on from their grief, then Chris is a symbol for 9/11. When Changez goes to visit Erica in the clinic,the nurse he meets when he first enters tells him that, â€Å"It did not matter that the person Erica was in love with was This was included to show Cahngez’s changing relationship with America and an alternative way to show how America is broken and how because of America’s tendency to look back, and hold on to the past prevented America fro building relationships with outher countriesIf you did not connect that Erica was America you might hink that this was about a Pakistany that came to American and wound up hating and criticisming it until he left. In reality it was about a man, or boy rather, that had big dreams of his life in America, ones that seemed to be coming true. But just as Erica could not let go of the past, America couldn’t let go of the hatred and fear they held for those who seemed un-American.

Unchopping a Tree Summary

SUMMARY OF UNCHOPPING A TREE by William Stanley Merwin Merwin’s Unchopping a Tree is a procedural essay as we can infer from the title alone. Here, Merwin describes what it takes for one to put together again a tree that has been cut down. Note that the author is very accurate in his steps so as to ensure that the tree will be exactly what it was when the rebuilding is done. According to Merwin, we have to start with the leave sand all others that belong to the tree’s crowning glory.They have to be put back exactly the way they used to be. Everything that used to be there has to be there again—exactly the way it was. Next in line is the trunk. Everything has to fit like the pieces of a jigsaw puzzle. There must not be a single misplaced splinter. The next thing to do is to raise the trunk and place it on the stump. This, he says, is no small enterprise because you have to use the proper fixative and that is difficult since, as he says, â€Å"again we have no dup licate for the original substance†.Now for the last step—we lower the splintered trunk unto the stump. Here, you have to gather the chips and sawdust and they must be returned to their former positions. Another problem is presented in this last step—bark sawdust decomposes very quickly if exposed to the elements. Once that problem is dealt with, you now have to find a translucent adhesive that is not so rigid. So your tree is now erected but is still held upright by the support of the scaffolding.And you take a restless night. In the morning, you remove the scaffolding. You cross your fingers in hope that the gentle breeze won’t push the tree over and that’s all you can do. And there we can conclude that a tree is really difficult to â€Å"unchop†. But, may I ask, why do we easily take down trees? Would we still find it easy to chop a lot of trees down once we’d experience unchopping just one tree?