Thursday, March 19, 2020
Most Common Plastics Below are five of the most common plastics used for different applications along with their properties, uses and trade names. Polyethylene Terephthalate (PET) Polyethylene Terephthalate- PET or PETE- is a durable thermoplastic that shows tough resistance to chemicals, high energy radiation, moisture, weather, wear, and abrasion. This clear or pigmented plastic is available with trade names such as: Ertalyte TX, Sustadur PET, TECADUR PET, Rynite, Unitep PET, Impet, Nuplas, Zellamid ZL 1400, Ensitep, Petlon, and Centrolyte. PET is a general purpose plastic that is made by polycondensation of PTA with ethylene glycol (EG). PET is commonly used for making soft drink and water bottles, salad trays, salad dressing containers, peanut butter containers, medicine jars, biscuit trays, rope, bean bags, and combs. High-Density Polyethylene (HDPE) High-Density Polyethylene (HDPE) is a semi flexible to hard plastic that can be easily processed by catalytic polymerization of ethylene in slurry, solution, or gas phase reactors. It is resistant to chemicals, moisture, and any sort of impact but cannot stand temperatures exceeding 160 degrees C. HDPE is naturally in the opaque state but can be colored to any requirement. HDPE products can be safely used for storing food and drinks and so it is used for shopping bags, freezer bags, milk bottles, ice cream containers, and juice bottles. It is also used for shampoo and conditioner bottles, soap bottles, detergents, bleaches, and agricultural pipes. HDPE is available under trade names of HiTec, Playboard, King Colorboard, Paxon, Densetec, King PlastiBal, Polystone, and Plexar.Ã Polyvinyl Chloride (PVC) Polyvinyl Chloride (PVC) is present in both rigid and flexible forms as unplasticised Polyvinyl Chloride PVC-U and Plasticised Polyvinyl Chloride PCV-P. PVC can be obtained from ethylene and salt by vinyl chloride polymerization. PVC is resistant to fires because of its high chlorine content and is also resistant to oils and chemicals except aromatic hydrocarbons, ketones and cyclic ethers. PVC is durable and can withstand aggressive environmental factors. PVC-U is used for plumbing pipes and fittings, wall cladding, roof sheeting, cosmetic containers, bottles, window frames, and door frames. PVC-P is commonly used for cable sheathing, blood bags, blood tubing, watch straps, garden hoses, and shoe soles. PVC is commonly available under trade names of Apex, Geon, Vekaplan, Vinika, Vistel, and Vythene. Polypropylene (PP) Polypropylene (PP) is a strong yet flexible plastic that can withstand high temperatures up to 200 degrees C. PP is manufactured from propylene gas in presence of a catalyst such as titanium chloride. Being a lightweight material, PP has high tensile strength and is highly resistant to corrosion, chemicals, and moisture. Polypropylene is used to make dip bottles and ice cream tubs, margarine tubs, potato chip bags, straws, microwave meal trays, kettles, garden furniture, lunch boxes, prescription bottles, and blue packing tape. It is available under trade names such as Valtec, Valmax, Vebel, Verplen, Vylene, Oleplate and Pro-Fax. Low Density Polyethylene (LDPE) Low Density Polyethylene (LDPE) is soft and flexible as compared to HDPE. Low Density Polyethylene shows good chemical resistance and excellent electrical properties. At low temperatures, it shows high impact strength. LDPE is compatible with most foods and household chemicals and acts as a poor oxygen barrier. Because it has very high elongation as a result of its molecular structure, LDPE is used in stretch wraps. This translucent plastic is mainly used for plastic food wrap, garbage bags, sandwich bags, squeeze bottles, black irrigation tubes, garbage bins, and plastic grocery bags. Low density polyethylene is made from the polymerization of ethylene in an autoclave or tubular reactors at very high pressures. LDPE is available in the market under the following trade names: Venelene, Vickylen, Dowlex, and Flexomer.
Tuesday, March 3, 2020
Can You Take the SAT in College SAT / ACT Prep Online Guides and Tips For many students, the SAT is one of the biggest stressors to comeup during high school. Few anticipate, though, that it may still be a concern during college. Occasionally, however,you might find that you need new SATscores after high school. So can you take the SAT in college? Yes, you absolutely can. There is no regulation that forbids it. In fact, the College Board's website specifically discusses non-high school testers. This article will discuss why you might need to take the test as a college student and coversome solid information about that process- and what makes it both unique and challenging. 2 Common Reasons to Take the SAT in College The SAT isn't a ton of fun. Why would yousubject yourselfto it when you're already in college? Well, actually, there are a few reasons youmay need to take the SAT in college. Applying for Jobs or Scholarships More and more job applications are requiring test scores, and there are scholarships out there for people who score within a certain range. Usually, high school scores serve for these purposes, but not everyone takes the test in high school. Thus, aneed to take the test later arises. It's important torealize that every company and every organization is different. You must adhere to the policies ofthese individual companies and organizations if you want them to take you seriously. Do your research, and, if you can't find the answer on the internet, make sure you call or email for clarification. The hope is that you'll get a message like this the moment a companysee your scores. Transferring Schools The most commonreason that you may need to take the SAT in college is if you are seeking to transfer schools. It's immensely importantfor anyone thinking about transferring to do research into the specific requirements of the school in question. A good place to start would be to read our complete guide to how test scores play into a transfer. Many schools require test scores from potential transfers. Some have different requirementsif you transfer in your first or second year versusif you transfer later on. This is very specific to the school. Some schools recommend including test scores under certain circumstances, but not others- this is often related to how soon after high school you began your college career. Some schools ask for test scores but permit exceptions for those who never took the SAT in high school or for whom taking the SAT now would be unduly difficult. Still other schools are test-optional or test-blind. In other words, they don't require scores. At test-optional schools, you can send scores if you wish, and at test-blind schools, your scoreswill not be considered under any circumstance. This applies to both transfer students and applicants goinginto college for the first time. It may be worthwhile to read our complete guide on the topic. All this goes to show that colleges are all a little bit different. Know the policy of the school you're applying to. The first place to check for this information is on the college's website. Many have a special page covering transfers, which you can find through the admissions or application page. If you can't find the specifics you're looking for on the website, though, there's nothing wrong with emailing a contact person at the school for clarification. Ideally, you should write to someone in the admissions department (as listed on the college's website). Failing that, though, give the college a call- a phone number for their offices should definitely be listed. Yes, that's right: make a real, old-fashioned phone call. Logistics of Taking the SAT in College There are quite a few hoops to jump through when it comes to taking the test, regardless of whether you're in high school or college. It's important to know what you're getting into. How to Register You can register online or by mail. This will involve answering a number of questions about basic personal information, courses taken, etc., as well as submitting a photograph of yourself. It's a good idea to get familiar with the process before you dive right into it. Where You Can Take It You'll be taking the SAT at one of the same test centers as all the local high school students. When you register online, you can easily search for and select the most convenient option. You may have some options; you may be able to choose a location such as a local university or communitycollege campus. Regardless, you will be taking the test with high school students. Choose the test center where you'll feel most comfortable. What's Different Taking It Now Logistically, the big differences are the more stringent requirements when it comes to identification and the difficulty of getting on the waitlist. You should also note that this is age-based; college students younger than 21 don't need to sweat these differences. If you're 21 years old (or older), a student ID is unacceptable identification on test day. You must bring official, government-issued identification, such as a driver's license or passport. Also, if you're 21 years old (or older), you simply cannot be placed on the waitlist. It's impossible, by the College Board's decree. The moral of the story, then, is to register on time and avoid the issue altogether. Additionally, you should be aware that the SAT recently underwent a complete overhaul. If you're in college now, you likely took the SAT on the 2400-scale (if you did take it). We're now on a 1600-scale. The essay is technically optional, though advisable in most cases. Some content has been redesigned, abandoned, or added.Sentence completion questions, asking you to define vocab with minimal or no context, are gone. Trigonometry, on the other hand, now makes an appearance. The essay no longer asks you to argue an opinion but to analyze a passage. In short, it's not quite the test you may remember. Advice for Testers in College Remember that the SAT tests high school topics, not college topics. Don't be fooled into thinkingthat means it's very basic or somehow below you; itdoesn't necessarily make matters easier. There are likely to be a few fundamental concepts that you've gotten rusty on. This may be especially true depending on your major. If you haven't taken any math classes in college, you may have forgotten certain exponent rules or whether47 is a prime number. In other words, even though the topics may not be college-level,per se, you still need to prepare. C'mon, it won't bethat miserable. 3 Key Tips for SAT Prep in College Once again, I cannot stress enough the importance of taking some time to prepare for this test. #1: Familiarize Yourself With the SAT's Specific Style Oddly enough, the SAT tends to reward pretty literal thinking on reading and writing (don't stray far from what the textactually says), while it rewards fairly creative thinking on math (be prepared to move expressions around into novel configurations). #2: Dust Off Rusty Topics Some of the material on the SAT may feel ancient and unfamiliar. This will not do; you've got to get handy with this content. There are many helpful resources out there, but don't forget that practice makes perfect. From full-length practice tests to individual practice problems, dive into experiencing the content firsthand. #3: Consider Your Schedule and Your Needs For many people, college is a very busy season of life. From gruelingclasses, to vibrant social events, to extracurricular commitments, things tend to move at a fast pace. Nonetheless, you still need to prepare before taking the SAT. So, start your preparationprogram well ahead of the test date. Consult your calendar (and syllabi) before committing to a specific test date. You definitelydon't want to wind up taking the SAT the weekend before/after a major exam or project. You don't want to overbook yourself. Conclusion In this guide, we've covered some basics regarding why to take the SAT in college and how to get that ball rolling. While there are a few definite differences versus taking the test in high school, the fundamentals are basically the same. Logistically, the process is almost identical. You'll be at the same sort of test center, and you'll register the same way. All the same rules and regulations apply, only you will need official government-issued identification and you can't get on the waiting list(depending on your age). You will still need to prepare, just like any high school student. Don't dismiss this step- it's crucial. In fact, give yourself extra time, considering how busy college can get. What's Next? The big question is how to prepare for the test. Remember that it's not quite like it was when you were in high school, and take a peek at our complete guide to studying for the test (revisions and all). If you're shooting for a perfect score, there are a few tips that can really boost your chances- including the simple advice of viewing all questions as analytical. There are some great resources out there, such as those created by the College Board's officiallyendorsed resource, Khan Academy. However, Khan Academy will never be enough- learn why. Want to improve your SAT score by 160 points?We've written a guide about the top 5 strategies you must be using to have a shot at improving your score. Download it for free now: