Polyvinylchloride (PVC) Essay Example | Topics and Well Written Essays - 250 words

Polyvinylchloride (PVC) - Essay Example PVC is highly unstable and therefore it requires stabilization which can be done in several ways. One of the common ways is prevention of dehydrochlorination. This process involves the addition of other compounds like metal oxides in order to stop or slow dehydroclorination. Most of the commercially available PVC is understood to be anamorphous glass like polymer that has crystalline structure. These crystallites are made up of few monomers that are arranged syndiotactically. As such, the appearance appears to be flowing grains that has primary aggregates embedded in them. It is often claimed that there are sub-primary particles embedded in the flowing grains but this has remained controversial. The PVC’s phase structure combines with several compounds such as chlorinated polyethylene (CPE), ethylene-vinylacetate copolymer (EVA) and acrylo-nitrile-butadiene rubber (NBR). This phase is predicated upon compatibility as well as process temperature and blending during mechanical blending. An increase of the temperature during mechanical processing of PVC to levels higher than the critical levels recommended for first degree particle fusion leads to shift. The shift leads to an inversion whereby there is a higher rubber content with 30% being non

Formation of an Alkene by Alcohol Dehydration Essay Example for Free

Formation of an Alkene by Alcohol Dehydration Essay Beer’s Law is an empirical relationship that relates the absorption of light to the properties of the material through which the light is travelling. In turn, absorbance is proportional to concentration and the higher the concentration, the higher the absorbance. This experiment incorporated Beer’s Law and is focused on determining the stress that various alcohols have on biological membranes. Using five solutions of differing alcohol concentration for each of the three alcohols; methanol, ethanol, and 1-propanol and a small slice of beet, the stirred solution was placed into a plastic cuvette and then into a spectrophotometer and the absorbance of alcohol solutions were determined in order to conclude which alcohol and concentration of alcohol had the greatest effect on biological membranes. The results showed that the most non-polar of the alcohols being tested, 1-proponal, caused the greatest damage to the biological membrane, the beet cell’s vacuole. INTRODUCTION The boundary between any cell and its environment is the plasma membrane, composed of a matrix of phospholipids molecules with many different kinds of proteins. Membranes have different properties and a variety of functions, in large part determined by the specific proteins within the membrane. The purpose of this experiment is to observe the effects of various alcohols on biological membranes, to determine the stress that various alcohols have on biological membranes and to conclude which concentration of alcohol has the greatest effect on biological membranes. The central plant vacuole of plant cells contains water and solutes, including water-soluble pigments. Its membrane, the tonoplast, is normally poorly permeable to water. The central plant vacuole of the root cells of beet contains a water-soluble red pigment, betacyanin, which gives the beet its characteristic color. Since the pigment is water-soluble and not lipid soluble, it remains in the vacuole when cells are healthy. If the tonoplast and the plasma membrane are damaged, the vacuole’s contents will leak out into the surrounding environment. Membrane disruption generally occurs when the cell is dead. Methanol, ethanol and 1-propanol are very similar alcohols, differing only in the number of carbon and hydrogen atoms within the molecule. One possible reason why these alcohols are so toxic to living organisms is that they might damage membranes. The polarity of methanol, ethanol, and 1-propanol comes from the OH group where the electrons are affected. The longer the R group the less the attraction. If 1-propanol is the most non-polar alcohol of the alcohols being tested, then 1-proponol will cause the greatest damage to the biological membrane, the beet cell’s vacuole. The effect of three different alcohols, methanol, ethanol, and 1-propanol, were tested on the beet vacuole membranes in this experiment. A measure of absorbance was collected using a conductivity probe. If a beet cell’s vacuole membrane (the tonoplast) was damaged, the red pigment, betacyanin, leaked out of the cell. The more red pigment that leaked out into the surrounding environment and the more intense the pigment, the greater the absorbance and the amount of cellular damage sustained by the beet. RESULTS The absorbance of methanol, ethanol, and 1-propanol were collected after the alcohol solutions of differing concentrations were placed in the plastic cuvette and then into the spectrophotometer. The absorbance of methanol, ethanol, and 1-proponal followed a general trend; the absorbance of the alcohol increased in relation to the rise in concentration of each alcohol solution. Figure 1. The graph depicts five solution of differing alcohol concentrations for each of the three alcohols; methanol, ethanol, and 1-propanol. The alcohol with the highest measurement of absorbance was the non-polar 1-proponal. (Figure 1) DISCUSSION The results (Figure 1), in general, support the original hypothesis that if 1-propanol is the most non-polar alcohol of the alcohols being tested, then 1-proponol will cause the greatest damage to the biological membrane, the beet cell’s vacuole. Hence, 1-proponal had the highest absorbance. The polarity of methanol, ethanol, and 1-propanol comes from the OH group, where the electrons are effected. The longer the R group the less the attraction between the molecules. In turn, methanol, ethanol, and 1-propanol are arranged from most polar to non-polar. At concentrations of 20% methanol, 10% and 20% ethanol, and 20% 1-propanol, the absorbance did not follow the general trend of data. This is due to sources of error in this experiment. There proved to have many sources of error in this experiment given the data gathered in this study and the evidence to this point. Sources of error include the size and surface area of the beat, cross contamination, and puncturing the beet during the stirring of solution. If the size and surface area of the beet slices were not uniform, bigger slices of beets had the potential to secrete a larger quantity of red pigment and a greater intensity in color in turn, increasing the absorbance. If the alcohol solutions were not stirred in order from lowest concentration to highest concentration, cross contamination would have occurred. If lower concentrations of alcohol are diluted with higher concentrations of alcohol, the absorbance of the lower concentration of alcohol will increase. If the beet was punctured during the stirring process, a greater amount of red pigment leaked out into the surrounding environment and in turn, the absorbance is increased. Beer’s Law is an empirical relationship that relates the absorption of light to the properties of the material through which the light is travelling. Beer’s Law is represented as A = ? bc (1) Where A is equal to the absorbance, ? is equal to the molar absorbtivity, b is equal to path length, and c is equal to concentration. In turn, absorbance is proportional to concentration and the higher the concentration of the red pigment that leaks out into the surrounding environment, the higher the absorbance of the alcohol.

Anton Chekhov’s Use of Grief in Misery and Vengeance Essay -- Misery, V

Anton Chekhov’s Use of Grief in â€Å"Misery† and â€Å"Vengeance.† What is the fascination with grief and suffering that caused Anton Chekhov to entwine these two sad emotional states into everything he wrote? â€Å"Reading Anton Chekhov’s stories, one feels oneself in a melancholy state. Everything is strange, sharp, lonely, motionless, helpless† (Nebraska 1). Further, according to William Gerharde, Chekhov answered this very question with the following: â€Å"When you depict sad or unlucky people, and want to touch the reader’s heart, one should try to be cold— it gives their grief, as it were, a background, against which it stands out in greater relief† (Gerharde 110). While Chekhov uses pain and suffering in all his stories, he does an especially effective job with two short stories â€Å"Misery† and â€Å"Vengeance.† In both, Chekhov introduces a similar theme, although it is first suggested in â€Å"Misery†: â€Å"The theme of the individual isolation is suggested in many of Chekhov’s early stories, but it is first fully developed in the brief sketch ‘Misery’,† (Winner 137). While reading â€Å"Misery,† the reader can absorb Chekhov through the twined themes of loneliness and isolationism. This enables characters to become so real that each reader can relate through the characters and the situation. One reason â€Å"Misery† is so well thought of by critics is that â€Å"the story takes a powerful look at the lack of human involvement and compassion towards one man’s grief† (Guevara 2). Of course, almost all who read the story have felt such loneliness or grief at one ti me or other in their lives and can, therefore, relate to the protagonist’s pain and isolation. In addition, the atmosphere in â€Å"Misery,† suggest grayness and depression, a setting that immediately conveys ... ... is factually correct, a trivial kind of truth, though a kind central to works of verisimilitude; saying that which, by virtue of tone and coherence, does not feel like lying, a more important kind of truth; and discovering and affirming moral truth about human existence— the highest truth of art† (Creighton, 1). Chekhov is able to contribute to all three of the ways there is to â€Å"tell it like it is† when writing fiction. Not only does he tell the truth in his writing, he does so in a down to earth and straightforward way. Reading Chekhov, is like reading someone’s daily journal. It is real, it is intense, and it makes the reader deeply feel for the characters involved in each individual story. Pain and suffering are commonly used emotions, so people can relate easily to the characters. This is what makes Chekhov such a successful writer, and why he was adored by all.

Millennium Development Goals Essay

The term â€Å"sanitation† is applied to a wide range of subjects such as: * Improved sanitation – refers to the management of human faeces at the household level. This terminology is the indicator used to describe the target of the Millennium Development Goal on sanitation, by the WHO/UNICEF Joint Monitoring Programme for Water Supply and Sanitation. * On-site sanitation – the collection and treatment of waste is done where it is deposited. Examples are the use of pit latrines, septic tanks, and Imhoff tanks. * Food sanitation – refers to the hygienic measures for ensuring food safety. * Environmental sanitation – the control of environmental factors that form links in disease transmission. Subsets of this category are solid waste management, water and wastewater treatment,industrial waste treatment and noise and pollution control. * Ecological sanitation – an approach that tries to emulate nature through the recycling of nutrients and water from human and animal wastes in a hygienically safe manner. Sanitation can be of three types Personal sanitation Sanitation at home Sanitation at surroundings. â€Å"Wash your hands before you eat†¦ give those germs a clean sweep.† 1) Personal sanitation :- a) Bathing regularly b) Washing your hands after using washroom c) Washing your hands before having food d) Cutting your hairs clean e) Cutting your nails & keeping them clean f) Drinking clean water,using chlorine tablets or boiling it 2) Sanitation at home a) Keeping your home clean b) Keeping washroom at home clean c) Using washroom rather than going in open d) Eating healthy & nutritious food e) Washing fruits before eating 3) Surroundings a) Saniataion at school b) Sitting on clean benches c) Cleanliness while playing at playgrounds d) Dressing/cleaning your wounds e) Don’t play at dirty places f) Stay away from hazardous chemicals Why sanitation is important 1) To keep you healthy 2) You will smell good 3) Waste attracts disease carrying hosts like rats & other scavengers. 4) In our country most of the diseases are caused due to contaminated water and poor sanitation. In tribal areas, there are shortage of water supply and lack of awareness about proper sanitation till today. People depend on the water of polluted rivers or ponds and suffer from lack of sanitation. These cause highly infectious diseases such as – diarrhea, malaria, cholera, jaundice, plague etc. If we follow clean sanitation and use purified water then we can easily control and avoid many of the above diseases.

Binomial System

Lesson 1 Assignment Questions Describe the scientific system by which plants are classified, in a report of up to 500 words. In this report, Cover: *the significance of the binomial system *why common names of plants should not be used to correctly identify plants. The scientific system to classify and naming plants are controlled and coordinated by botanist throughout the world. The system of classification in plants is to classify them in groups with similar characteristics. Then continue to divide and sub-group until you have one type of plant in each group.The main level of division in plants are as follows: Plants are divided into PHYLA (singular: phylum) Phyla can be divided into DIVISIONS Divisions are divided into CLASSES Classes are divided into ORDERS Orders are divided into FAMILIES Families are divided into GENERA (singular: genus) GENERA are divided into SPECIES Species are sometimes divided into VARIETIES The concept of the binomial system was introduced by Carolus Linn alus (1707-1778) in 1753 for flowering plants. The system gives each plant a name which is made up of two parts.The first part is called the generic name (or genus) and always starts with a capital. The second part is the specific name (or epithet) and always comes after the generic name. The specific name always starts with lower case, unless it is name after a person or place. The reason common names should not be used is that some common names are given to more than one plant creating confusion when communication about plants. Using botanical names allow identification worldwide. Common names can verify from one country to the next.Answer each of the following briefly. A. What are the major divisions found in the plant kingdom? The major divisions found in the plant kingdom is Phyla, Division, Classes, orders, Families, Genera, Species and Varieties. B. List the basic differences between angiosperms and gymnosperms. The basic difference is that angiosperms are a flowering, seed p lant produce seeds within a fruit, while the gymnosperms are naked seed bearing. The gymnosperms have seeds that are not enclosed by an ovary of fruit. C. Define the meaning of the termsFamily: A taxonomic category of related organisms ranking below an order and above a genus. A family usually consists of several genera. Genus: A taxonomic category ranking below a family and above a species and generally consisting of a group of species exhibiting similar characteristics. In taxonomic nomenclature the genus name is used, either alone or followed by a Latin adjective or epithet, to form the name of a species. Species: a. A fundamental category of taxonomic classification, ranking below a genus or subgenus and consisting of related organisms capable of interbreeding. b.An organism belonging to such a category, represented in binomial nomenclature by an uncapitalised Latin adjective or noun following a capitalized genus name, as in Ananas comosus, the pineapple, and Equus caballus, the horse. Subspecies: A taxonomic subdivision of a species consisting of an interbreeding, usually geographically isolated population of organisms. Variety: A taxonomic subdivision of a species consisting of an interbreeding, usually geographically isolated population of organisms. Cultivar: A race or variety of a plant that has been created or selected intentionally and maintained through cultivation.D. Give the scientific names of 10 different plant species not mentioned elsewhere to date in this course. For each, indicate which family they belong to, which name is the genus, which is the species and (if applicable) which is the variety or cultivar. Name:Syzygium australecultivar Family: MyrataceaeGenus:SyzygiumSpecies: S. australe Name:Viola hederaceacultivar Family: ViolaceaeGenus:ViolaSpecies: V. hederacea Name:Hardenbergia violaceacultivar Family: FabaceaeGenus:HardenbergiaSpecies: H. violacea Name:Acacia vertillata Family: MimosaceaeGenus:AcaciaSpecies: A. verticillataName:Bulb ine bulbosa Family: LiliaceaeGenus:BulbineSpecies: B. bulbosa Name:Pultenaea dentata Family: FabaceaeGenus:PultenaeaSpecies: P. dentata Name:Dichelachne rara Family: PoaeceaeGenus:DichelachneSpecies: D. rara Name:Diuris orientis Family: OrchidaceaeGenus:DiurisSpecies: D. orientis Name:Leptospermum scoparium Family: MyrataceaeGenus:LeptospermumSpecies: L. scoparium Name:Wahlenbergia gracilenta Family: CampanulaceaeGenus:WahlenbergiaSpecies: W. gracilenta 3. What is the horticultural significance of juvenility, maturity and senescence in the developmental cycle of a plant.The horticultural significant of juvenility, maturity and senescence in the developmental cycle of a plant is each stages allows different advantages of the plant. The ability for juvenile stage to be influence allows propagators to vegetatively propagate cuttings longer, while to reduce this stage allows flower and fruit growers to reduce their production costs and an earlier crop or return on investment. Because at this stage it has its most rapid rate of growth and has the ability to initiate adventitious roots readily, this is decreased or lost as the plant matures.Maturity is significant for those wanting to see the results of their breeding programs or a harvest from the plants e. g. seeds and fruits. A plant is considered mature when it has the potentially capacity to reproduce. Reproduction from cuttings at this stage is reduced or the plant has no longer got the ability to form adventitious roots. Senescence is referred to the process involving the deterioration of the plant or its organs prior to death. To be able to control or delay this stage allows for a longer harvest time e. g. fruit and flowers. . Answer each of the following questions briefly. A. Describe the structure of the basic plant cell. Explain the function of the different cell organelles. The basic plant cell structure is made many layers which primary consist of three components being the middle lamellum, primary cell wall and secondary cell wall. There are many cell organelles: Nucleus stores the genetic component (chromosomes) of the particular cell. Plastids are collective terms for organelles that carry pigments. Ribosome’s are responsible for the synthesis of proteins.Mitochondria are there to break down the complex carbohydrates and sugars into usable forms for the plant. Golgi Body transports chemical substances in and out of the cell. Endoplasmic Reticulum is the link between the nucleus and the cytoplasm of the plant cell. Vacuoles are used for storage and help to regulate turgor pressure of the plant cell. Peroxisomes is to assist chloroplasts in undergoing photorespiration process. They also contain certain oxidative enzymes. B. Define the term â€Å"Plant Tissue†. Describe the characteristics and basic role of tissue found in flowering plants.Plant Tissue is the references to a collective function of large tracts of cells with similar structure. Plant tissues come in tw o basic types Meristematic tissues and Permanent tissue. The meristematic basic role is to actively divide and differentiate into various cell types. After the Meristematic cells have divide they develop into Permanent tissue. Permanent tissue can be classified into simple or complex. C. Draw and label the cross section of a leaf to show epidermis, xylem, phloem, stomata and parenchyma. â€Å"See Attached†D. Draw and label a cell diagram to show all parts you can remember without referring to your notes. â€Å"See Attached† 5. Answer the following question briefly. A. State the internal differences between monocotyledons and dicotyledons. There are numerous differences between monocotyledons and dicotyledons. |Monocotyledons |Dicotyledons | |A large number of vascular bundles |A limited umber of vascular bundles | |The vascular bundles are scattered in the |The vascular bundles are arranged in a ring | |Parenchyma tissue. | | |Between the cortex and pith there is no | There is a clear distinguish between the corted | |Distinction. And the pith | |No secondary thickening |Secondary thickening can occur | |No annual rings are formed |Due to secondary thickening annual rings are | | |formed | |No cambium occurs between the xylem and |Cambium occurs between the xylem and the | |The phloem. Phloem. | B. How can strengthening tissue establish in monocotyledons in order for perennial growth to occur? The stem strengthening occurs by the many vascular bundles being scattered, rather than in a ring, with support for the bundles being surrounded by extensive fibres. â€Å"See Attached† for 14 plants, 7 review sheets.