Attention Defecit Hyperactivity Disorder - 2565 Words

Introduction Attention Deficit Hyperactivity Disorder (ADHD) a neurobehavioral and cognitive disorder that is characterized by inattentive, impulsive and hyperactivity symptoms (Ko et al., 2013). It is a highly prevalent disorder among child and adolescent populations although approximately 15% of patients have been found to meet full symptom criteria into adulthood (Hoogman et al., 2013). ADHD has been related to various cognitive deficits in major areas of executive functioning such as planning, working memory decision making, goals setting, emotional attending (Ernst et al., 2003; Ko et al., 2013; Hulvershorn et al., 2014). In the past several decades, as technology has advanced and become more available for research purposes, researchers have been interested in looking at the neurological substrates that underpin Attention Deficit Hyperactivity Disorder. Many studies since have found that abnormalities in various regions of the brain are closely associated with specific behavior al and cognitive deficits that that are characterized by ADHD. The purpose of this paper is to examine more in depth the neurological substrates and underpinnings of ADHD and its associated behavioral deficits. An extensive review of the past research in this area has revealed a myriad of different brain regions and networks which are related to various deficits and behaviors in individuals who have ADHD. I will be describing and discussing the general findings of these studies in hopes toShow MoreRelatedHey Teacher, leave recess alone! In her Huffington Post blog article titled Here’s One Way to Wreck700 Words   |  3 PagesA longitudinal study that followed over 10,000 students between the ages of 8 and 9 concluded that student recess of at least 15 minutes resulted in better behavior as rated by teachers (Samuels, 2009). Case studies of boys with attention-defecit hyperactivity disorder at a private school conducted by Andrea Ridgeway and her colleagues concluded that behavior problems increased considerably when the boys were not given recess. Sometimes as much as a 30% increase in problematic behavior comparedRead More Attention Defecit Disorder Essay2038 Words   |  9 PagesAttention Defecit Disorder Attention deficit disorder, also called ADD, is defined as a disorder primarily a characteristic of childhood, marked by a consistent problem in paying attention, in the book, The Lifespan by Guy R. Lefrancois (1999). It is more common among boys than girls but can effect all ages. Focusing on children between the ages of five thru ten, it is estimated that three to five percent, which is 1.35 - 2.25 million, of all children are living with ADD. When accompaniedRead MoreADHD: A Pandemic Without a Disease1954 Words   |  8 Pagesyou know there is a medically diagnosed disorder that affects over two American children?† Experts on the subject say there are many more undiscovered cases out there and the cause is still unknown. It sounds like we have a really big problem. The thing is, the disorder that affects all these children, isn’t a disorder at all. Attention-deficit/hyperactivity disorder is a set of behaviors that are considered a medical problem. In reality, it isn’t a disorder. It is a fad that somehow got started

Behavior Of Plastic Fibers In Concrete - Myassignmenthelp.Com

Question: Discuss about the Behavior Of Plastic Fibers In Concrete. Answer: Introduction Various fields including science and construction industry have been greatly attracted by the Use of plastic fibers to strengthen concrete as compared to other types of steel. This paper has analytically presented the present state of information and technology of adopting plastic fibers to reinforce concrete. A detailed review of the effects of plastic fibers on the fresh and hardened concrete properties have also been covered in this paper(Ozel, 2009, p. 552). Among the many reasons for the occurrence of cracks, ion concrete elements are the deformation as a result of shrinkage. The concrete elements vary ranging from pavements, overlays and even slabs. Polypropylene fibers in most cases help to improve the cement based composites which are more vulnerable to shrinkage. The deformations may be caused by very many factors such as restrained shrinkage, autogenously and also increased composite resistance. In the first 12 hours of concrete shrinkage, the plastic fibers reduce and lessen the presence of cracks by harnessing the strength and capacity of the cement paste(Mertz, 2008, p. 844). When these cracks are not controlled, the small tiny cracks formed due to the drying shrinkage results in the growth of larger cracks. The fibers also help in reducing the width of the cracks thereby preventing harmful substances from the environment from penetrating. Generally, the control of cracks is vital for the advancement of more durable and long-lasting structures. Literature review Fiber Reinforced Concrete that contains a tough material enhances the structural integrity of the concrete due to the uniformly distributed fibers. There are two Types of Fibers which include the; Steel Fibers Synthetic Fibers- this includes the plastic fibers. These Fibers are primarily used in concrete for the below purposes; For the prevention of cracking which forms as a result of both drying and plastic shrinkage(bton, 2007, p. 322). Besides, the fibers help to enhance the robustness of the concrete. Fibers also help to limit the penetrability of the concrete and thereby lessening water leakage during construction. Advantages of Fiber Polypropylene and Nylon Fibers these type of fibers are mostly applied due to their property of improving the mixing cohesion and also the ability to pump over longer distances. They also exhibit the property of increasing the resistance that results from freeze-thaw or explosive palling during incidents of severe fire .for this reason, these fibers have been internationally recommended since apart from offering protection to the concrete it also helps to protect lives and property(Hensher, 2016, p. 985). Steel Fibers- these type of fibers also are advantageous in terms of Improving the structural strength of concrete and Reducing the size of the cracks by firmly holding and in turn promoting its durability nevertheless, steel fibers Improves abrasion resistance and freeze-thaw resistance(Paramanantham, 2015, p. 548) Role of fibers The process of crack formation in concrete elements plays a key role since it constantly exposes the structures to a high risk of corrosion. Theses crack lower the quality of the concrete, therefore, affecting their durability and also their aesthetic value. Hence there is a need to minimize the size of these cracks and more particularly this is achieved with the addition of plastic fibers. There are various reasons behind the formation of these cracks including; Fire damage, plastic shrinkage, freeze-thaw damage and also plastic settlement as discussed below. Plastic shrinkage These stakes place when the water present at the surface evaporates prior to the bleeding water reaching the surface. The addition of the plastic fibers will help minimize the extent of the shrinkage crack due to their property of flexibility and also ability to fit into form(Pielert, 2011, p. 646). Plastic settlement This occurs when there is a high rate of bleeding and the presence of some resistance when settling. The plastic fiber when added will help to fix this problem since they are uniformly distributed and flexible thereby ionizing the resistance experienced(A.E. Naaman, 2014, p. 993). Freeze-thaw damage The addition of plastic fibers in concrete helps to limit the flow of water by inhibiting the flow of water through the small nodes. This implies that there will be an improvement in cement hydration and also a reduction of the water flow or leakage which results in the cracking(R.N. Swamy, 2015, p. 763). Fire damage The presence of heat or fire creates penetrative ways into the concrete thereby disporting the moisture which is present on the outer layer. These moisture vapors get back into the cold interior parts and get reabsorbed. These vapours when accumulates increases the pressure rapidly and eventually results into palling and concrete racks. The addition of plastic fibers releases the vapor pressure into new voids thus reducing the extent of spalling(Antonio Nanni, 2014, p. 420). Properties of Plastic Fiber Reinforced Concrete Prior to the mixing of concrete, certain variables that are adjusted to inhibit the fibers from balling. These variables may include the fiber length, amount and design mix variables. Best mixes typically will comprise of an increased volume of mortar as matched to the conventional concrete mixes which are normally restricted between 100 and 200 to minimize difficulties that may arise during construction. Conventionally, plastic fibers are randomly and uniformly distributed in the concrete; nonetheless, to obtain greater strengths the concrete is placed such that the fibers get lined up in the direction of applied stress Below are some of the properties of the plastic fibers These fibers are applied in two ways i.e. In thin sheet components where they provide the primary reinforcement and the volume content of fiber is comparatively high such that it exceeds 5% purposefully to attain both solidification and strengthening(Yin, 2017, p. 777). The other way of applications is when the volume content is relatively low such that it less than 0.3% thereby providing the secondary reinforcement for specifically for crack control, Effects of plastic fibers on concrete Plastic fibers have various influences on both fresh and hardened concrete as discussed below Effects on Fresh Concrete The workability of fresh concrete is normally determined by a parameter known as the slump test. The value of the slump is influenced by the content of water and its absorption properties. Also, it is attributed to the texture, shape and the surface characteristics of the components forming the mixture. The addition of the plastic fibers to the concrete decreases these value slowly. Thereby resulting in an increase in the bond and cohesiveness of fresh concrete. The plastic fibers shear apart during the mixing of the components thus creating an interconnection of the individual fibers and the fiber filaments. As a result of the large surface area, the fibers mechanically anchor to the cement paste(Clarke, 2009, p. 877). This mixture has a reduced rate of bleeding and aggregate settlement due to the firm holding of the concrete by the plastic fibers. As a result of the high tensile strength of the plastic fibers, early plastic shrinkage cracking is greatly managed by improving the tensile capacity of plain concrete to provide resistance to the tensile stresses initiated by the typical volume changes. Moreover, the fibers uniformly distribute these tensile tensions all over the concrete and with the decrease in plastic shrinkage cracking, concrete cracks get reduced. In the event that shrinkage cracks get formed, they get managed by the plastic fibers which reduce their size and width(James Shackelford, 2007, p. 542). Below is a table of the effect of the plastic fibers Effects on Hardened Concrete. Plastic fibers do not have a significantly greater effect on the compressive strength or elastic modulus but only on the tensile strength. As discussed below, the Addition of plastic fibers intensifies the splitting of the tensile strength by approximately 30% to 60%. Compressive strength This is a vital factor in concrete since it determines other parameters such as the tension and flexure among others. It is realized that the addition of plastic fibers will either reduce or increases the compressive strength of concrete through the overall effect is always negligible. Flexural tensile strength: it is observed that with an increase in the amount of the added plastic fiber, the tensile strength increases(AL-GHAMDY, 2012, p. 763). Bond strength: Typically, the bond between the matrix and the fiber should be desirable and upon attaining the strengthening critical fiber volume, multiple racking then gets easier to achieve. These multiple cracks when loosely spaced reduces the possibility of harmful substances from penetrating. The plastic fibers offer High bond strength that helps to provide close crack spacing(Singh, 2016, p. 552). Fracture Properties: the addition of fibers improves the failure behavior of high-strength concrete. Creep and shrinkage properties: Fibers help to minimize the creep strain rate and also concrete shrinkage that is caused by the removal of water from concrete during drying. Since the fibers do not shrink, they will be able to delay the process of shrinkage thereby overall reducing the deformation(Jochen Bundschuh, 2010, p. 998). Chloride penetration: Apart from the improved mechanical properties, the addition of plastic fibers also reduces the possibility of penetration by chemical substances such as chloride since the interfacial transition zone in the direction perpendicular is blocked(Baoguo Han, 2017, p. 620). Obstacles in Use of Plastic fibers Despite the use of plastic fibers gaining popularity, there is still need to do some improvements. Of significant note is the poor bond provided by some plastic fibers which provide a reduced pull-out strength. Incidents of fire also may result in cracking of greater porosity. The plastic fibers are also prone to destruction when exposing to too much sunlight and oxygen since they do not have a well-designed protection system. Further, due to reduced elasticity as compared to the cement matrix, the fibers sometimes acts as an initiator of the small cracks thus creating more pores in the cement elements(Berga, 2011, p. 531). Evaluation Analysis The recent design and construction of new buildings have taken into recognition the use of plastic fibers for the purposes of controlling shrinkage cracking and deformation. The application of these fibers is recommended for concrete structures as a result of the improved performances and effective cost-benefit ratio. Below are some of the advantages that make the plastic fibers recommendable for use in concrete structures(Mindess, 2014, p. 332). Plastic fibers are compact and easy to pump and place, Plastic fibers provides a safer working environment Plastic fibers also limit the rebound effect by improving the strength of wet concrete. Since the plastic fibers are entirely synthetic, chances of corrosion are greatly reduced. Plastic fibers also show enhanced impact resistance when compared to conventionally reinforce brittle concrete(Gustavo J. Parra-Montesinos, 2012, p. 542). Besides, plastic fibers improves the abrasive resistance in concrete floors by regulating the bleeding during the early stages of concrete cracking Also, plastic fibers increase the tensile strength and impact resistance thereby providing a reduction in the weight and thickness of structural components(Ying-shu Yuan, 2015, p. 833). Conclusion In conclusion, the research was based on the determination of the behavior of plastic fiber on concrete. It has been noted that plastic fibers offer the best reinforcement to concrete as compared to other reinforcement fibers. Below were some of the reason that demonstrated the best characteristics of plastic fibers in the prevention of crack formations in concrete elements. When concrete is reinforced with plastic fiber, there is improved cohesion in the mixture and also the ability to pump over longer distances. Cases of fire breakouts also are countered by offering a stronger resistance to the explosive spalling. Besides, apart from improved structural strength and ductility of the mixture, plastic fiber offers a high resistance to the shrinkage during. The research also indicates that plastic fibers help to improve the resistance to freezing thaw and abrasion. The above properties ensure that the width of the crack formed in the concrete material is greatly reduced thereby improving the lifespan and the aesthetic value of the concrete. References A.E. Naaman, H. R., 2014. High-Performance Fiber Reinforced Cement Composites 2. 5th ed. Chicago: CRC Press. AL-GHAMDY, D. O., 2012. EFFECT OF MATRIX COMPOSITION ON STEEL FIBER REINFORCED CONCRETE PROPERTIES. 3rd ed. Chicago: University of MICHIGAN, Antonio Nanni, A. D. L. H. J. Z., 2014. Reinforced Concrete with FRP Bars: Mechanics and Design. 3rd ed. Carlisle: CRC Press. Baoguo Han, L. Z. J. O., 2017. Smart and Multifunctional Concrete Towards Sustainable Infrastructures. 5th ed. Westminster: Springer, Berga, L., 2011. Dams and Reservoirs, Societies and Environment in the 21st Century. 3rd ed. Chicago: Taylor Francis,. bton, f. F. i. d., 2007. FRP Reinforcement in RC Structures. 4th ed. new york: fib Fdration Internationale du bton. Clarke, J., 2009. Alternative Materials for the Reinforcement and Prestressing of Concrete. 4th ed. Westminster: CRC Press, Gustavo J. Parra-Montesinos, H. W. R., 2012. High-Performance Fiber Reinforced Cement Composites. 2nd ed. Chicago: Springer Science Business Media. Hensher, D. A., 2016. Fiber-Reinforced-Plastic (FRP) Reinforcement for Concrete Structures:. 3rd ed. Carlisle: Elsevier, James Shackelford, R. H. D., 2007. Ceramic and Glass Materials: Structure, Properties and Processing. 2nd ed. Carlisle: Springer Science Business Media. Jochen Bundschuh, M. C. S. A., 2010. Introduction to the Numerical Modeling of Groundwater and Geothermal Systems: Fundamentals of Mass, Energy and Solute Transport in Poroelastic Rocks. 3rd ed. Westminster: CRC Press. Mertz, D. R., 2008. Application of Fiber Reinforced Polymer Composites to the Highway Infrastructure, 2nd ed. new york Transportation Research Board. Mindess, S., 2014. Developments in the Formulation and Reinforcement of Concrete. 5th ed. new york Elsevier. Ozel, M., 2009. The behaviour of concrete beams reinforced with 3-D fibre reinforced plastic grids. 2nd ed. Chicago: University of Wisconsin--Madison, Paramanantham, N. S., 2015. Investigation of the Behavior of Concrete Columns Reinforced with Fiber Reinforced Plastic Rebars. 2nd ed. Westminster: Lamar University. Pielert, J. H., 2011. The significance of Tests and Properties of Concrete and Concrete-making Materials. 2nd ed. Chicago: ASTM International,. R.N. Swamy, B. B., 2015. Fibre Reinforced Cement and Concretes: Recent Developments. 3rd ed. Westminister: CRC Press, Singh, H., 2016. Steel Fiber Reinforced Concrete: Behavior, Modelling and Design. 3rd ed. Melbourne: Springer. Singh, H., 2016. Steel Fiber Reinforced Concrete: Behavior, Modelling and Design. 2nd ed. Carlisle: Springer. Ying-Shu Yuan, S. P. S. H.-l. L., 2015. PRO 32: International Conference on Advances in Concrete and Structures. 5th ed. new york RILEM Publications. Yin, S., 2017. Development of Recycled Polypropylene Plastic Fibres to Reinforce Concrete. 2nd ed. Chicago: Springer.

Sports Info Essay Example For Students

Sports Info Essay supplements range from protein shakes to illegal anabolic steroids. Some sports izzle out, while others still work well but do more damage than good in the long run. In the past athletes had to turn to such things as anabolic steroids or blood doping (the process of taking out blood and adding oxygen to it and putting it back into your body in order to increase a persons endurance). However, these procedures have many drawbacks. Mainly, thCreatine One of the primary things an athlete will do is put supplements into their body. ey are illegal. An athlete may be suspended from playing their perspective sport for using them. They have many long terms and short term side effects. Many supplements are as simple as packaged energy and others require a strict exercise and eating regimen. I will explore sports supplements focusing on creatine and its effect on the sport world. The first and most basic sports supplements are protein weight gainers. This normally comes in the form of powder and works best when mixed with milk. The main reason for taking extra protein is to gain weight and muscle mass. In todays athletics, whether it is high school, college, or professional, the athletes are getting bigger and stronger. Protein works the best when the athlete is on a strict work out regimen. Many sports supplements are a combination of herbs and proteins. A popular supplement of this sort is called Heat. Heat has many different ingredients in it that allow the athlete to experience more energy by creating more heat. This allows the athletes body to work more efficiently and therefore work faster, stronger, and longer. This is very important in the sports world because it is becoming harder and harder to compete at an unsupplemented level. Athletes want every advantage that he or she can receive. Now there is a substance that can give an athlete the edge that they desire. One of the most popular and effective sports supplements on the market today is Pure creatine Monohydrate. Creatine was first introduced to the US in 1993 by a supplement company called Experimental and Applied Sciences. Since that time it has become one of the most demanded items on the market. The creatine that is bought in stores duplicates the natural creatine that is produced by the kidney, liver, and pancreas. Creatine Monohydrate has been proven to significantly enhance athletic performance in the areas of power, strength, and muscle mass. Most importantly though, it doesnt seem to have any serious side effects. Also, since Creatine is found naturally in the body and in foods, it is likely that it will not be removed from sports. What is Creatine? Creatine is a nutrient that is found in many foods. It is most highly concentrated in lean red meat. A half-pound of red meat contains about two grams of Creatine. Every human body also produces Creatine in very small amounts, though some people produce more than others. Creatine is necessary for proper cell functions and cell reproduction, it is also a primary storage for energy in muscles. How does Creatine work? When somebody is exercising, his or her muscles demand energy. The energy that the muscle gets is called adenosine triphosphate (ATP). As the muscles keep contracting, the ATP is turned into adenosine diphosphate (ADP). ADP causes your muscles to fatigue. Creatine Phosphate helps to convert ADP into ATP when the ATP is gone. In doing this, the athlete has better endurance during his of her workout or event. Creatine producers and users claim it to have many advantages, such as increased endurance, increased overall work potential, increased speed of muscular action, and the potential to further increase muscle mass. Creatine also accelerates protein synthesis. If all this were true, it would be easy to see why athletes are turning to Creatine for an edge on their competition. But are these claims real? Is their scientific proof of what Creatine does? Yes, since Creatine came onto the supplement market it has been tested extensively. Research in human sports science indicates that if you supplement a normal diet with Creatine it will increase the Creatine content in the muscles. Truth Exposed in Body Rituals among the Naciremas Essay If anything creatine requires one to increase their workouts and effort, because the bodys tolerance to exhaustion is higher. Another problem that people may see with creatine is the cost factor. A Creatine supply for a month will average close to forty-five dollars. With the cost of this and other supplements being so high, it seems that the higher class athletes would have an advantage, which causes many critics of creatine(or supplements in general) to deem it unfair. Their case is, athletes of one group should not be permitted to have an advantage over another due to something such as money. In conclusion, Creatine is and can be a very effective supplement for athletes, it doesnt help everyone. Depending on the person and the sport they are participating in creatines effects can be either positive or negative. Though long term research on the effects of creatine have not been confirmed, as of now the only side effects are diarrhea, nausea, and weight gain. These are outweighed by the increased success that one may have in their strength and performance in sports. Creatine has a positive effect on sports as well as its negative effect, therefore each person should weigh the positive and negative, then make the decision for themselves. Fall Back On Fitness As we head into the cooler autumn months, we undoubtedly expect that the upcoming holiday seasons surrounding Thanksgiving, Halloween, and (yes, already) Christmas will lead to our spending more and more time indulging and less and less time keeping ourselves healthy and fit. This doesnt have to be the case. We are not bears, and regardless of what one may think, we do not need to store up extra fat so that we may hibernate for the winter! Awareness of the potential pitfalls of the holiday season can prevent the pounds from sneaking up on you. Treat yourself to an early gift by purchasing a journal in which you can keep a daily record of your eating, exercise and stress behaviours. Keep an eye on your journal entries so that youll notice your less than healthy behaviours and make changes before you get overwhelmed. One suggestion is to weigh yourself once a week during the holiday season. One study of weight loss over a 50-week period found that some study participants gained 500 percent more weight per week during holiday weeks as compared to non-holiday weeks. But the good news: Participants who consistently monitored and recorded their own behaviours were able to lose weight during the holidays. (Published in Health Psychology, July 1998.) The next suggestion is to remember that your body needs movement more than ever during the holiday season. Exercise releases tension, expends the calories of those holiday goodies, increases your energy levels so you can shop til you drop, elevates your mood so you can combat holiday-related depression and be the life of the party, and gives you the gift of time for yourself. Here are some great ways to fit exercise into the busy fall season: ? Exercise first thing in the morning before you begin your busy day. ? Try to plan holiday activities around family and friends, instead of around food. Tell family and friends to bring walking shoes and comfortable clothes to your celebration. Then take a 30-minute walk together. You can do it in shifts so someones always basting the turkey! ? Get into a routine now, before the holidays strike! Those who have previously developed a solid exercise habit will make the time to exercise even when they feel like they are ?too busy? to find the time. Sports and Games