Tensile Properties of Polypropylene

Tensile Properties of Polypropylene Introduction If an engineer wanted to design a bridge to span a river, it would be absurd to consider building it out of papier-mà ¢chà © or rubber. We know this because we know something about the demands that will be put on the bridge and we know that these materials do not satisfy the requirements. After considering other materials, perhaps titanium or high tech aluminium alloys, we may discount them on the grounds of cost even if they do have suitable mechanical properties to make a good bridge. Eventually we may decide on steel; but which one? There are thousands to choose from. Which has the best properties at an affordable price? The cost effectiveness of any material is a matter not to be dealt with here but we must ask which steel has the most appropriate physical properties. In order to answer this question, we must conduct tests on different steels and compare the results when samples of the steel are tested to destruction. Polypropylene has the ability to crystallise which was a very exciting prospect as it is also an economical material so the popularity of it grew and production began all across most of Europe its use. Lots of different types of polypropylene have been under production since the early 1950s mainly because of its insulating properties. it is used in many different fields, bumpers and some of the interior in a car is developed using polypropylene its also widely used in electrical components because of its great electrical resistance at high temperatures. It has similar properties to polyethylene. Because of its use in many different fields its necessary to test the material in a variety of ways. In this test the tensile properties will be examined at different testing speeds. This test is done because The test process involves placing the test specimen in the testing machine and slowly extending it until it fractures. During this process, the elongation of the gauge section is recorded against the applied force. The data is manipulated so that it is not specific to the geometry of the test sample. Theory Polypropylene, like other plastics, typically starts with the distillation of hydrocarbon fuels into lighter groups called fractions some of which are combined with other catalysts to produce plastics (typically via polymerisation or poly-condensation) For example, the polymerisation of propylene, which is identical to ethylene except that one hydrogen substituent has been replaced by a methyl (CH3) group, yields polypropylene. This material has a higher melting point (160-170 oC), higher tensile strength, and greater rigidity than polyethylene. Figure 1- Propylene monomers polymerisation to polypropylene Depending on how they are linked or joined (chemical bonds or intermolecular forces) and on the arrangement of the different chains that forms the polymer, the resulting polymeric materials can be classified as: Thermoplastics Elastomers Thermosets Depending on the chemical composition, polymers can be inorganic such as glass, or they can be organic, such as adhesives of epoxy resin. Organic polymers can be also divided into natural polymers such as proteins and synthetic polymers as thermosets materials. Description of apparatus The apparatus used the most for the testing part of the experiment was the zwick tensile testing machine this is a highly accurate piece of equipment as it has high resolution angle measurement which allows excellent repeat accuracy. This type of machine has two crossheads; one is adjusted for the length of the specimen and the other is driven to apply tension to the test specimen he machine must be able to generate enough force to fracture the specimen. The machine must be able to apply the force quickly or slowly enough to properly mimic the actual application. Finally, the machine must be able to accurately and precisely measure the gauge length and forces applied Figure 2- Tensile testing machine (diagrammatic sketch form) Test procedure The test will be carried out using the Zwick tensile testing machine, with 3 different specimens each of them will be extended at different speeds Specimen 1: Extension speed= 100 mm/min Specimen 2: Extension speed= 50 mm/min Specimen 3: Extension speed= 12.5 mm/min Before testing the specimens, they must be measured before and after the test to see what impact the test had on the specimens After the measurement, have been taken its required to make a table to compare the load to the extension this graph will be required to estimate relevant values that will be needed to complete the calculations. For all the specimens you are required to obtain a verity of tensile properties including: Nominal yield stress Youngs modulus Fracture stress (nominal and true) Tensile ductility Results Specimen (mm) Average (mm) Av.CSA = tw ( 1 T 2.13 2.18 2.20 2.17 10.20 W 4.68 4.73 4.70 4.70 2 T 2.13 2.15 2.16 2.14 10.10 W 4.68 4.72 4.71 4.70 3 T 2.14 2.15 2.16 2.15 10.11 W 4.70 4.72 4.69 4.70 Specimen 1 calculated results when extended at speed of 100 mm/min Gauge Length (mm) 33.00 Initial cross-sectional area () 10.21 Fracture length (mm) (55-33) 22.00 Thickness at fracture (mm) 0.91 Width at fracture (mm) 2.50 Cross-sectional area at Fracture () 2.28 Load at yield (N) 270.00 Load at fracture (N) 170.00 Nominal yield stress () 26.45 Extension at high yield (mm) 1.54 Young modulus () 566.79 Nominal fracture stress () 16.65 True fracture stress () 74.56 Tensile Ductility (mm) 0.66 Specimen 2 calculated results when extended at speed of 50 mm/min Gauge Length (mm) 33.00 Initial cross-sectional area () 10.10 Fracture length (mm) (123-33) 90.00 Thickness at fracture (mm) 0.93 Width at fracture (mm) 2.61 Cross-sectional area at Fracture () 2.43 Load at yield (N) 262.50 Load at fracture (N) 172.50 Nominal yield stress () 25.99 Extension at high yield (mm) 1.54 Young modulus () 556.93 Nominal fracture stress () 17.08 True fracture stress () 70.98 Tensile Ductility 2.72 Specimen 3 calculated results when extended at speed of 12.5 mm/min Gauge Length (mm) 33.00 Initial cross-sectional area () 10.11 Fracture length (mm) (242-33) 209.00 Thickness at fracture (mm) 0.88 Width at fracture (mm) 2.01 Cross-sectional area at Fracture () 1.77 Load at yield (N) 273.75 Load at fracture (N) 267.50 Nominal yield stress () 27.08 Extension at high yield (mm) 110.26 Young modulus () 8.08 Nominal fracture stress () 26.46 True fracture stress () 151.13 Tensile Ductility 6.33 Calculations of average cross sectional area specimen 1 Average cross sectional area = Average thickness x Average width Average cross sectional area = 2.17 mm x 4.70 mm = 10.20 Calculations of specimen 1 Nominal yield = Nominal yield = = 26.45 Youngs modulus= Youngs modulus= = 566.79 Nominal fracture stress = Nominal fracture stress = = 16.65 True fracture stress = True fracture stress = = 74.56 Tensile ductility = Tensile ductility = = 0.66 mm Graphs Figure 3- Graph of load vs extension for specimen 1- Figure 4- Graph of load vs extension for specimen2- Figure 5- Graph of load vs extension for specimen 3- Discussion Unsurprisingly when you inspect between the three graphs you can see a slight pattern occur which is that the faster you extend the Polypropylene the quicker it breaks. The graph readings are used to find how much it was extended when broken so that the tensile ductility can be worked out. There have been errors in the graphs because in the laboratory the measured extension of the break was 22mm whereas the zwick tensile testing machine made a graph that showed it to be a lot less around 8mm which is surprising to have such a varied result. Retrieving most of the results from the graph required a lot of estimation because specimens one and two had scales of 20 and specimen 3 had a scale of 50 these both arent precise enough to get an accurate reading of the graph so a lot of estimation was required. As it can be seen in the results the extension at high yield point was very different for specimen 3 compared to the other specimens, this at first glance could be considered as an anomaly even though this was expected because the less stress that is put on the specimen meant that the extension of the yield would be higher but such a big gap wasnt expected. However, looking at the results of the other groups in the lab it shows that the result is acceptable. The other result that differed in specimen 3 when compared to the other specimens was the load at fracture this is because specimen 3 extended for a much longer distance then the other two so there was much more load at fracture which meant that the fracture stress was much greater too as shown in the results. Also, glass transition temperature had to be controlled so that the polypropylene wasnt too brittle, as temperature is hard to get accurate most of the readings might have differed because of it. Conclusion It can be seen in this test how speed effects the tensile properties of polypropylene, as the results and graphs show that when tension is applied quicker as its done in the first specimen it can take a lot less stress to break the polypropylene compared to the 3rd specimen which took a lot more tension because it expanded much more than the other 2 specimens as seen in figure 6. The results of the test are reliable but improvements could have been made the graph could have a much smaller scale which would have made the readings off the graph much easier to obtain. Also, there were assumptions that were made while doing this for example when working out the youngs modulus we had to assume that the line between the origin and the high yield point is linear. Figure- 6 Photos of the 3 specimens before and after the test. References Information https://www.creativemechanisms.com/blog/all-about-polypropylene-pp-plastic http://www.bpf.co.uk/plastipedia/polymers/pp.aspx https://en.wikipedia.org/wiki/Tensile_testing Images http://www.chemistry.wustl.edu/~edudev/Designer/session4.html

Philosophy of Curriculum Essay

My philosophy of curriculum as it pertains to this course and through my new eyes at the end of the course, points to the constructivist-style curriculum as the most logical, meaningful, purposeful, intellectual, and authentic exemplars to model after. Focusing on a more educational description of constructivism, the meaning is intimately connected with experience. I believe students come into a classroom with their own experiences and a cognitive structure based on those experiences. These preconceived structures are valid, invalid or incomplete. The learner will reformulate his/her existing structures only if new information or experiences are connected to knowledge already in memory. Inferences, elaborations and relationships between old perceptions and new ideas must be personally drawn by the student in order for the new idea to become an integrated, useful part of his/her memory. Memorized facts or information that has not been connected with the learner’s prior experien ces will be quickly forgotten. In short, the learner must actively construct new information onto his/her existing mental framework for meaningful learning to occur. So what is the support structure for a constructivist learning setting and how do they differ from a classroom based on the traditional or didactic model? The current American classroom, whether grade school or college level, tends to resemble a one-person show with a captive but often comatose audience. Classes are usually driven by â€Å"teacher-talk† and depend heavily on textbooks for the composition of the course. There is the idea that there is a fixed world of knowledge that the student must come to know. Information is divided into parts and built into a whole concept. Teachers serve as pipelines and seek to transfer their thoughts and meanings to the passive student. There is little room for student-initiated questions, independent thought or interaction between students. The end result is that the instruction set forth for the learner is solely memorization of the facts and no conceptual depth and understanding (Erickson 30). In a constructivist setting, knowledge is not objective; mathematics and science are viewed as systems with models that describe how the world might be rather than how it is. This is an example of the differences between the world of the declarative and procedural knowledge and thinking to understanding the critical empirical and explanatory principles within the curriculum. The role of the teacher is to organize information around conceptual clusters as seen in a concept map and in Gowin’s Vee, in order to help pose questions and unusual situations to engage the student’s interest. Teachers assist the students in developing new insights and connecting them with their previous learning. Ideas are presented holistically as broad concepts and then broken down into parts. The activities are student centered and students are encouraged to ask their own questions, carry out their own experiments, make their own analogies and come to their own conclusions and then eventually applying the new found knowledge and information to brand new situations. Becoming a constructivist teacher is a difficult change since most teachers are prepared for teaching in the traditional manner. It has taken me these past two school years to â€Å"shift my paradigm† and adopt a new one but it does work if you are dedicated to putting in the time and effort to building your own curriculum built around the standards and back by the foundations that have been laid by Piaget, Dewey, Novak, Gowin, Erickson and the many others. These psychologists and experts in the mind and education have contributed to the following characteristics of what I believe is a representation of a constructivist teacher: 1. One of many resources that the student may learn from, not the primary source of information. 2. Engage students in experiences that challenge previous conceptions of their existing knowledge. 3. Allow student responses to drive lessons and seek elaboration of students’ initial responses. Allow student some thinking time after posing questions. 4. Encourage questioning by asking thoughtful, open-ended questions. Encourage thoughtful discussion among students. 5. Use cognitive terminology such as â€Å"classify,† â€Å"analyze†, and â€Å"create† when framing tasks. 6. Encourage and accept student autonomy and initiative. Be willing to let go of classroom control. 7. Use raw data and primary sources, along with manipulative and interactive physical materials. 8. Don’t  separate knowing from the process of finding out. 9. Insist on clear expression from students. When students can communicate their understanding, then they have truly learned. In summary, constructivist teaching offers a bold departure from traditional didactic classroom strategies. The goal is for the learner to play an active role in absorbing knowledge onto his/her existing mental framework. The ability of students to apply their school-learned knowledge to the real world much more valued over memorizing bits and pieces of knowledge that may seem unrelated to them. Curriculum designed with the constructivist approach requires the teacher to relinquish his/her role as sole information-dispenser and instead to continually analyze his/her curriculum planning and instructional methodologies. Clearly, the constructivist approach opens new avenues for learning as well as challenges for the teacher trying to implement it but isn’t it worth it? I believe it is worth every ounce.

Bookbinders Book Club Essay

1. Before beginning any case, students should familiarize themselves with the model being used. Marketing Engineering for Excel comes with tutorials that demonstrate the capability of each model. The tutorial can be found under each model within the ME>XL menu after starting Excel. These tutorials are designed to work with our OfficeStar examples which are located in the My Marketing Engineering directory, usually installed in My Documents during software installation. The data required for this case is located in two files in the My Marketing Engineering directory (usually located within My Documents): Bookbinders Book Club Data (Customer Choice). xls Bookbinders Book Club Data (Customer Choice) Holdout Sample. xls 2. Introduction About 50,000 new titles, including new editions, are published in the United States each year, giving rise to a $20+ billion book publishing industry. About 10 percent of the books are sold through mail order. Book retailing in the 1970s was characterized by the growth of chain bookstore operations in concert with the development of shopping malls. Traffic in bookstores in the 1980s was enhanced by the spread of discounting. In the 1990s, the superstore concept of book retailing was responsible for the double-digit growth of the book industry. Generally situated near large shopping centers, superstores maintain large inventories of anywhere from 30,000 to 80,000 titles. Superstores are putting intense competitive pressure on book clubs, mail-order firms and retail outlets. Recently, online superstores, such as www. amazon. com, have emerged, carrying 1–2. 5 million titles and further intensifying the pressure on book clubs and mail-order firms. In response to these pressures, book clubs are starting to look at alternative business models that will make them more responsive to their customers’ preferences. Historically, book clubs offered their readers continuity and negative option programs that were based on an extended contractual relationship between the club and its subscribers. In a continuity program, popular in such genres as children’s books, a reader signs up for an offer of several books for a few dollars each (plus shipping and handling on each book) and agrees to receive Copyright  © 2008 by DecisionPro, Inc. To order copies or request permission to reproduce materials, go to www. decisionpro. biz. No part of this publication may be reproduced, stored in a retrieval system, used in a spreadsheet, or transmitted in any form or by any means – electronic, mechanical, photocopying, recording or otherwise – without the permission of DecisionPro, Inc. a shipment of one or two books each month thereafter. In a negative option program, subscribers get to choose which and how many additional books they will receive, but the default option is that the club’s selection will be delivered to them each month. The club informs them of the monthly selection and they must mark â€Å"no† on their order forms if they do not want to receive it. Some firms are now beginning to offer books on a positive-option basis, but only to selected segments of their customer lists that they deem receptive to specific offers. Book clubs are also beginning to use database marketing techniques to work smarter rather than expand the coverage of their mailings. According to Doubleday president Marcus Willhelm, â€Å"The database is the key to what we are doing†¦. We have to understand what our customers want and be more flexible. I doubt book clubs can survive if they offer the same 16 offers, the same fulfillment to everybody. †2 Doubleday uses modeling techniques to look at more than 80 variables, including geography and the types of books customers purchase, and selects three to five variables that are the most influential predictors. The Bookbinders Book Club The BBB Club was established in 1986 for the purpose of selling specialty books through direct marketing. BBBC is strictly a distributor and does not publish any of the books it sells. In anticipation of using database marketing, BBBC made a strategic decision right from the start to build and maintain a detailed database about its members containing all the relevant information about them. Readers fill out an insert and return it to BBBC which then enters the data into the database. The company currently has a database of 500,000 readers and sends out a mailing about once a month. BBBC is exploring whether to use predictive modeling approaches to improve the efficacy of its direct mail program. For a recent mailing, the company selected 20,000 customers in Pennsylvania, New York and Ohio from its database and included with their regular mailing a specially produced brochure for the book The Art History of Florence. This resulted in a 9. 03 percent response rate (1806 orders) for the purchase of the book. BBBC then developed a database to calibrate a response model to identify the factors that influenced these purchases. For this case analysis, we will use a subset of the database available to BBBC. It consists of data for 400 customers who purchased the book, and 1,200 customers who did not, thereby over-representing the response group. The dependent variable for the analysis is Choice — purchase or no purchase of The Art History of Florence. BBBC also selected several independent variables that it thought might explain the observed choice behavior. Below is a description of the variables used for the analysis: Choice: Whether the customer purchased the The Art History of Florence. 1 corresponds to a purchase and 0 corresponds to a nonpurchase. Gender: 0 = Female and 1 = Male. Amount purchased: Total money spent on BBBC books. Frequency: Total number of purchases in the chosen period (used as a proxy for frequency. ) Last purchase (recency of purchase): Months since last purchase. First purchase: Months since first purchase. P_Child: Number of children’s books purchased. BOOKBINDERS BOOK CLUB CASE 2/4 P_Youth: Number of youth books purchased. P_Cook: Number of cookbooks purchased. P_DIY: Number of do-it-yourself books purchased. P_Art: Number of art books purchased. To assess the performance of the model, the data set includes a second sheet with 2300 customers–a holdout sample representative of the entire target market. The use of such a validation sample is an appropriate way to compare alternative models. BOOKBINDERS BOOK CLUB CASE 3/4 EXERCISES BBBC is evaluating three different modeling methods to isolate the factors that most influenced customers to order The Art History of Florence: an RFM (Recency, Frequency and Monetary Value) model, an ordinary linear regression model, and a binary logit model. 1. Summarize the results of your analysis for all three models. Develop your models using the case data files and then assess them on the holdout data sample. Interpret the results of these models. In particular, highlight which factors most influenced the customers’ decision to buy or not to buy the book. Bookbinders is considering a similar mail campaign in the Midwest where it has data for 50,000 customers. Such mailings typically promote several books. The allocated cost of the mailing is $0. 65/addressee (including postage) for the art book, and the book costs Bookbinders $15 to purchase and mail. The company allocates overhead to each book at 45 percent of cost. The selling price of the book is $31. 95. Based on the model, which customers should Bookbinders target? How much more profit would you expect the company to generate using these models as compared to sending the mail offer to the entire list? Based on the insights you gained from this modeling exercise, summarize the advantages and limitations of each of the modeling approaches. Look at both similar and dissimilar results. As part of your recommendations to the company, indicate whether it should invest in developing expertise in any of these methods to develop an in-house capability to evaluate its direct mail campaigns. How would you simplify and automate your recommended method(s) for future modeling efforts at the company. 2. 3. 4. 5. 6. 1 The case and the database were developed by Professors Nissan Levin and Jacob Zahavi at Tel Aviv University. We have adapted these materials for use with our software, with their permission. 2 DM News, May 23, 1994. BOOKBINDERS BOOK CLUB CASE 4/4

As Mentioned Above, There Have Been Many Lives Lost During

As mentioned above, there have been many lives lost during the civil war that has raged for years in Syria. The estimated casualties in the chemical attack on April 4th are reported to be 131 citizens, 41 of those children (Perez, 2017). Many more people were also affected by the attack that day. There are the countless friends and family members who lost loved ones. There are surely many others who lost homes and other possessions that will be forced to try to find new places to live and support themselves. In a much broader sense, the effects are seen on global society by the reactions of political leaders, press coverage by media outlets, and even individuals whose reactions are displayed on social media. In many ways, events like this†¦show more content†¦Again, these violations of social rights have become acceptable to some degree because they are thought to be necessary to prevent future attacks and ultimately stop those responsible. Many refugees of war are left with no way to provide for themselves or their families and become dependent on the donations and kindness of others. These effects demonstrate how events like the Syrian attack can have far reaching side effects on not only the direct victims, but for society across the globe. The victims of this attack are in need of medical assistance and many other basic needs as a result of this attack. While most people see and recognize this need, the social perception of terrorism and middle eastern countries involvement in these acts affects how people and governments react around the world. The social beliefs and values of cultures in the US and many other countries result in delays and debates in appropriate actions to help the people affected by this tragedy. The result is the continuation of the suffering of the Syrian people and uncertainty about if or when a resolution to this war will come. The analysis of this event brings about a much larger question as well, which is why do acts of wa r like the Syrian chemical attack continue to be issues after centuries of war and the lessons that society has learned from these experiences. Applying theShow MoreRelatedThe Battle Of Gettysburg As My Topic1083 Words   |  5 Pagesselected the Battle of Gettysburg as my topic to research. The reason I appointed this event as my subject matter was on the fact that I reside close to Gettysburg, and have heard of some of the events that developed there during the Civil War. Even though I live close to Gettysburg, I haven’t seen the reenactments that occur there or been on the tours Gettysburg offers. Since I would like to take part in a tour along with seeing the reenactments, I figured it would be helpful to gain a broader understandingRead MoreReading: Entertainment and Brain Exercise Essay622 Words   |  3 Pagesin the end. â€Å"Heightened connectivity in other parts of the brain suggested that readers may experience â€Å"embodied semantics,† a process in which brain connectivity during a thought-about action mirrors the connectivity that occurs during the actual action.†(www.theatlantic.com). This study out of Emory University, along with many others, shows that the neuron changes created by reading a book are associated with physical sensation and movement systems in your brain. When reading a word like coffeeRead MoreThe Black s Anatomy, And Acts As A Doctor Essay1350 Words   |  6 Pagesimportance of black lives and injustices. Throughout Jesses speech he discussed various prevalent issues regarding police brutality, inhumane deaths in African American communities; through ethos, pathos and logos, Williams effectively promotes a demand for social change. Throughout Jesse’s speech, he often used the terms â€Å"they and their†; thus, I presume that the audience omits the minority, in a reference to the â€Å"oppressors†, and prejudice people who do not want the minority to have equal opportunityRead MoreThe Victims Of Hate Essay1500 Words   |  6 PagesNikhil Simhambhatla Ms. Samantha Payne Language Arts II 11 May 2015 Victims of Hate Essay â€Å"Treat others as how you would like to be treated.† This is considered to be the â€Å"Golden Rule†. It is a rule embedded in many cultures and religions as a format on how to live life. Now, with that in mind, imagine a world where one is stuck in daily oppression, aloneness, and dogged, for nominal money if not none. Imagine a world where one is stuck in the world of an animal’s, eating out of troughs where theRead MoreLost Of A Romantic Comedy By Sofia Coppola1221 Words   |  5 PagesLost in Translation Lost in Translation, widely considered an independent film, but with overtones of a romantic comedy, written and directed by Sofia Coppola, is an intimate portrayal of loneliness and human connection told through two Americans called Bob and Charlotte who meet in Tokyo, Japan. Charlotte is having an early 20s existential â€Å"what do I do with my life† crisis whereas Bob who is much older than charlotte, is having a midlife crisis. Both characters are two people at opposite endsRead MoreHuman Rights And Its Effects On Society Essay1672 Words   |  7 Pagesshould have in society. As individuals, it’s our natural right to have the right to life. No one should be executed or discriminated because they do not fit in certain characteristics that those that are superior have outlined as fit for society. Many countries suffer from the lack of protecting their citizens’ human rights. For instance, citizens have been executed and discriminated because of their gender, race, and religion affiliations, which is unjust. Individuals have lost their lives becauseRead MoreThe Importance Of The Civil Rights Movement1692 Words   |  7 Pagespreserve. We shall nobly save, or meanly lose, the last best, hope of earth.†-Abraham Lincoln. The United States have been through numerous community changes that occurred and altered the history. The Civil Rights Movement of the 1960’s was one of the most significant and important for the equality of all people and their free rights. Since the ending of slavery in 1863, there had been a continuous conflict between the races of people who lived in the United States. In addition, the Civil Rights ActRead MoreReligion Fights Back1273 Words   |  6 PagesReligion Fights Back Introduction Before the Holocaust, Jewish people had ordinary lives. Children went to school, parents went to work or owned their own business. They carried on spiritual traditions and strived for their own goals. During the Holocaust though, Jews lost the meaning of life (Michalczyk 177). They were considered useless and a burden to the Germans. This was continuously beat into their minds not only mentally but also physically (Michalczyk 177). Some were able to beat theseRead MoreTechnology Is A Great Enhancement1565 Words   |  7 PagesTechnology is a great enhancement to human advancement. Throughout history, technology has always improved the lives of individuals. Technology has transformed the lives of numerous generations.This whole wave of technology was initiated by the invention of the plow. The plow launched the the agricultural revolution. The invention of the plow manipulated and changed the way people lived their lives. We all associate technology with all things progressive b ut most people do not associate it with negativeRead MoreBlack Political Thought And Activism1358 Words   |  6 Pages1963- 1968 saw a profound shift in black political thought and activism, it is a radical shift for black seeking to fight against racial oppression, establishment of black politic, and the improvement of black economy. Blacks had been through many oppressions from the whites. They were treated as the second class citizens even though they were also American. Those oppressions were mostly formed from the racism matter. With no longer endure to the oppression, a big wave of the black’s political thought