Airframe Structure Failure and Survivability Essay Example for Free

Airframe Structure Failure and Survivability Essay There are many different variables that come into play during an aircraft accident. It is an investigators job to find out what caused the failure. Failure of an aircraft primary structure is ranked high on the list of risks aircrews would rather not face. Mechanical component failure which can lead to loss of control of the aircraft is not far behind. Another issue which must be addressed in any aircraft accident is the question and of crash survivability. Even if no one was injured the investigator must find out what worked and what didnt. If there were injuries, several questions should be asked. The chapters I will be covering will give the investigator a look into what causes structural failure, and how to determine crash survivability. An aircraft accident investigators job is to determine what caused the crash. Structural failure is a vital part of the investigation. The term structure failure means where the material fails to carry below it was intended to carry. A structure can fail in one of two general ways. One way is it can be fractured, which means broken into two or more pieces. Another way is when the structure shape is changed so that it can no longer carry its load. With this kind of failure, the structure is still in one piece. It could be bent, stretched, corroded, or so worn that it can no longer do its intended job. Over the next few pages, I will be going into detail about the different ways structures can fail. There are many reasons why an airplane structure can fail. As I have just gone over a few in the last paragraph, there are many different ways this can happen. In chapter 35, the book talks about overload. This is, when an in-flight load exceeds the weight the part was designed for. All structures to include bridges, buildings or airplanes are created to withstand only specific loads. It is unrealistic to assume that airplanes can be designed and built to withstand any conceivable load it can experience. If a structure is exposed to a load greater than which it was designed for, it will structurally fail. Be it deforming, or fracturing into two or more pieces. These are two general reasons why aircraft structures fail. Aircraft structures are designed to withstand loads generated by air at some maximum airspeed and the loads generated while maneuvering at some G load. Most aircraft can be flown at speeds and G loads which can place excessive loads on the aircraft structure. Aircraft that is directly exposed to onrushing air could be damaged as the dynamic pressure of the air stream is converted to static pressure pressing inward on the structure. Excessive speed can reduce the airplanes stability. The bottom line is that a lot of bad things can happen when an aircraft exceeds it’s redline airspeed. One of the clearest reasons for failure of a structural component is that the component lacked the proper strength to withstand the loads created while the aircraft is flown at its normal operating limits. There are numerous reasons why a structural component could be understrength. It is possible that the engineering of the structure was inadequate. The designer could have possibly made an error which was not caught during the testing phase. Another reason could be that wear and tear caused a weakening to the structure. Service life issues are normally divided into four sub areas; fatigue cracking, corrosion, wear and creep. The four of these progressive failures which cannot be undone as the aircraft accumulates flight hours ground-air-ground cycles. An aircraft structure can be weakened in a somewhat short period of time. Exposure to heat can greatly reduce a metals strength. For example, some aluminum alloys that are exposed to temperatures of 400Â ° for 5 minutes can reduce the alloys strength by 80%. Jet engine hot sections and compressor bleed airlines are made of materials such as stainless steel or titanium alloys which maintain most of their strength in relatively high temperatures. This problem happens when structure which is not been designed for high temperature is exposed to high temperatures. Some aircraft which can reach high supersonic speeds require the leading edge structures to be able to withstand the extremely high temperatures generated at these speeds. There are two general areas when it comes to aircraft structures. You have a primary structure, and a secondary structure. The primary structure is parts of the aircraft that are necessary to safely fly its mission. The following components are normally considered to be part of the primary structure: wing structure, fuselage structure carrying flight, ground and cabin pressurization loads, empennage, landing gear structure, engine mounts and supporting structure. The primary structures can be further sub categorized as either critical structure or principal structure elements. Critical elements are those whose failure would result in catastrophic failure of the aircraft. Principal elements are those that contribute significantly to carrying flight, ground and pressurization loads whose failure could or could not result in catastrophic failure. The following components are considered to be the secondary structure: aerodynamic fairings, tail cones, and landing gear doors. There are other mechanical components which carry flight critical loads. Even though these components have failure modes that are closely related to those exhibited by the primary and secondary structures, they do not fall into either of those categories. Components like hydraulic pressure lines, drive shafts, electric alternators, and gear teeth in transmissions all have modes of failure which can give clues concerning the nature of the loads which caused them to fail. In aircraft accident investigator will have a firm understanding of the loads that airplane structured caries and the physical evidence that these loads leaves behind when they fail. The many types of loads are vectors and have both magnitude and direction. You can change the load by either changing its magnitude, for example increasing or decreasing the pounds of force being applied, or by changing its direction by applying force upward instead of down. Loads can take a finite length of time to be imposed. Even though loads can be applied in a very short period of time they can be applied or changed instantaneously. The fact that loads take time to apply and or change is important for the accident investigator understand. The book separates loads into three general areas; static loads, dynamic loads, and repeated loads. Knowing the difference between the three types is important because the nature of the load has a lot to do with the failure of the structure and the evidence left behind. If a load were applied so slowly that the structure to which the load was being applied to stayed equal at all times the load would be considered a static load. A static load can be either for short or long period of time. A dynamic load happens when the loads are applied fast enough to prevent the structure from carrying the load while remaining in equilibrium as the load is being applied. Dynamic loads can be divided into two subcategories, sudden, and impact. A sudden load will impose stronger internal stresses in the structure. Components such as landing gear are tested with dynamic loads. Impact loads are applied at faster rates than sudden, causing the structure to fracture almost every time. Impact loads are usually limited to high-speed bird impacts and crash tests. Repeated loads are just like they sound, loads that are repeated over and over again. Due to the behavior of dynamic impacts and longtime static loads, it makes them unlikely candidates for repeated loads. Short time static and sudden dynamic loads can be repeated over and over again. If a component goes through lots of repeated load cycles before it fails due to fatigue cracking it is said to have experienced high cycle fatigue. By lots of cycles the book means hundreds of thousands or millions or tens of millions of cycles. One of the ways investigators look at structure failure is to consider the time it took for the failure to occur. If the failure happened at the instance of a single load, it is called an instantaneous failure. If the failure took a period of time to occur, that is called a progressive failure. If a structural component contained a load that caused significant distortion, but did not exceed the materials yield stress, and the structure springs back to its original shape after the load is removed is called an elastic deformation/distortion failure. Now if the same events occur and the structure does not spring back to its original shape after the load is removed, that is called plastic deformation/distortion. This is a permanent shape change, unlike the elastic which is a temporary shape change. Now if the load reaches the point where internal stresses not only cause significant plastic deformation, they exceed the materials ultimate stress, the structure will then fracture and separate into two or more pieces. This is called a fracture failure. An experienced investigator can tell the difference between the five different types of structural failure. Another form that causes structural failures is corrosion. Corrosion is the natural disintegration of material as it is attacked by one or more substances in its environment. During the refining process, energy is added to metal ores and other raw materials in order to produce the mechanical properties necessary in structural components. Mother Nature the great equalizer, doesnt like variances in energy levels and sets to work trying to bring the material back to the low energy levels existing in the products of corrosion. When it comes to aircraft structural components, mother natures attack will reduce the strength and ductility of components turning strong metals into meek metallic oxides, hydroxides or sulfates. If these compounds are not removed from the structure they can worsen the problem by providing an environment which is ever more favorable to continued corrosion. There are many different forms of corrosion. Some can be the result of a direct chemical attack by reactive substances in the environment. Pitting is a common form of corrosion. Small holes that are randomly located across the metal surface are called pits and sometimes may be accompanied with a powdery residue. Even though pits may appear to have damaged only a small percentage of the surface, they penetrate deeply in a branching matter causing loss of strength and ductility which is way out of proportion to metals surface appearance. Chemical corrosion involves the reaction between a metal structure and some chemical agent. If you introduce corrosive acid on a metal wing, the acid and the metal will react to form new and undesirable compounds. A selective attack is when corrosive actions seem to favor one part of the components or assembly above another. The primary type of selective attack is intergranular corrosion. This type of attack centers on the grain boundaries with in a metal component before consuming the grains themselves. Similar to pitting the damage from this kind of attack causes a loss of strength and ductility which is out of portion the amount of metal that is corroded. Another form intergranular corrosion is exfoliation, whose progress and go undetected until all structural integrity is lost. Grain boundaries attacked by this type of corrosion are normally flattened and or elongated grains of extruded or rolled metals. This type of corrosion can move undetected along the grain boundaries. Slow removal of material from the surface of the component by a mechanical action is referred to as wear. In most cases wear is undesirable, wear during break in on new or overhauled equipment is often a necessary ingredient in establishing proper operation and long service life. The type of wear the book talks about is the kind that leads to premature failure and breakdown. Abrasive wear happens when small abrasive particles cut into and remove material from surfaces of two components which are held together while moving. When this type of wear happens one question an investigator must ask is, where did the particles come from? Adhesive wear occurs when microscopic projections of the surfaces of the two components which are sliding across each other may contact, weld together and break off. A question that an investigator can ask is was the surface lubricated? Erosive wear is similar to abrasive wear in that foreign particles are cutting tiny chunks out of the surface. Its a little different from abrasive wear in that the abrasive particles gain their penetrating energy by a fluid that is carrying them along. How did the particles enter into the fluids is a question an investigator could pose. To prevent structure failure, the components go through an inspection called non-destructive inspection (NDI). NDI are inspection techniques which will not do significant harm to the object being inspected. Other names for this type of inspection is called non-destructive evaluation (NDE) or non-destructive testing (NDT). There are six specific techniques for these inspections. First, visual inspection is the simplest form and most common of the NDI process and uses your God-given gift of sight. To assist this type of inspection, illumination, magnification, and remote viewing are used to help. Another type is dye penetrant. This inspection is used to detect small surface cracks and discontinuities which may not be visible during strictly visual inspections. This technique is simple, but time-consuming. The component being inspected is covered with a colored liquid which is absorbed into surface cracks. The liquid includes a phosphorescent material which when exposed to ultraviolet light glows in the dark so small surface cracks are visible to the naked eye. Magnetic particle inspection provides another way to assist the eye by increasing the conspicuity of a surface crack. This process requires more specialized equipment then the dye penetrant process, it makes the crack even more obvious if properly used. This inspection makes use of the fact that when a magnetic field is induced in a component made of Ferro-magnetic material, surface cracks will alter the components magnetic field. When magnetic particles are placed on a magnetized surface it will align themselves along the magnetic field showing any variations caused by the cracks. If the magnetic particles are phosphorescent and viewed in a dark room under an ultraviolet light pattern around the cracks will be more visible. Eddy current is the first technique that is discussed that does not require direct viewing of the crack. This process involves the use of a probe to generate both an electromagnetic field and sense and evaluate the Eddy current generated in the material being inspected. When either or surface or near surface cracks are in the material it will alter the shape of the Eddy current and magnetic field it generates. This can be as simple as a twitch on a meters needle. The equipment needed for this type of inspection must be calibrated for the specific design being inspected and the size of the crack being search. Ultrasonic inspections make use of high-frequency sound to find surface and subsurface defects. The high-frequency sound waves are generated by a transducer and then beamed through the part being inspected. The reflective waves or the remnants of waves which penetrate the part are being measured with a receiver and electronically evaluated. There are two different ways the sound waves can be applied to and retrieved from the part being inspected; immersion of the part into a fluid which carries the sound waves to and from the part and direct contact inspection where the transducer and receiver are in direct contact with the part. The direct contact technique is much more mobile allowing use in the field of the aircraft or major fabrications. Radiographic inspection in its simplest form is not much different than that of an x-ray. Very short wave electromagnetic radiation are generated and directed through the part being inspected and towards unexposed radiographic film. Rays passing through cracks, flaws, voids and corroded areas will not be attenuated as much as raise passing through sound material. To the untrained eye, cracks, flaws, voids and corrosion may appear to be just another shadow on the film. Orientation of the x-rays so as to illuminate the discontinuities and proper interpretation of the film are therefore important aspects in ensuring the thoroughness of the inspection. One of the issues which must be addressed in any aircraft accident is a question of crash survivability. Even if no one was injured, the question of what worked and what didnt work should always be asked. Did the restraint systems operate as designed? Whether or not escape hatches were needed, could they have been opened if needed? Did the emergency lighting system work? How crash survival equipment is designed is based on experience, history, and sound engineering judgment. To know if these components work correctly design requires an accident for verification. The accident is a chance to validate our judgment and we cannot afford to pass it up. To make investigation of aircraft crashes a little easier requires a systematic approach by breaking down a complicated series of events into smaller, more digestible bites. The approach chapter 36 goes over is the CREEP method. CREEP stands for: Container, Restraint, Energy absorption, Environment, and Post-crash factors. The first four of the five CREEP elements relate to the dynamic portion of the crash itself. These four factors are concerned with the initial and any subsequent impacts with the terrain, the associated deceleration forces acting on the aircraft and its current occupants, and the deformation and dislocation of aircraft structure and its contents. The fifth factor relates to the occupants attempts to egress the aircraft before suffering additional injuries not directly resulting from the dynamic portion of the crash. In order to survive a crash it is first necessary to provide a living space for the occupants during the dynamic portion of the crash. If the space is crushed or punctured, the chances of survival fall drastically. This factor is container. Now if the occupants have been provided with adequate living space, the next series of questions should deal with the restraint of the crew and its passengers and equipment and components around them. Occupants of any moving vehicle must be protected from injuring collisions with in the vehicle, for example being thrown against the sides of the living space or having objects such as cargo or equipment thrown at them. The strength of all restraints should be sufficient to prevent injury at the force levels which can be expected during the most severe but survivable crash. The investigator should examine all restraints system failures to determine if there failure contributed to injuries experienced by the crew or passengers. The deceleration forces created during a crash may be high enough to cause fatal or serious injuries, even if a safe living space, adequate crew and passenger restraints, and a delethalized flailing envelope are provided. Since crew and passenger bodies are not strongly attached to the airframe, the design of the aircraft structure and seeds may cause the acceleration forces experienced by the crew and passengers to be either amplified or attenuated. A soft deep seat cushion can greatly amplified the vertical Gs experienced by someone sitting in the seat. The deep seat cushion deforms at high loads absorbing energy as it gives can greatly reduce the vertical crash loads to which a seat occupant is subjected. Hopefully, the designers will build a secure box around the crew and passengers and secure them to it. Although we may be able to restrain the torso, it is normally impractical to secure the head and limbs of the crew and passengers. The volume through which the unrestrained extremities can be expected to move shouldve been the legalized to the maximum degree possible. Obstructions which could cause injury should either remove from within the flailing envelope or padded to reduce the severity or probability of injury. This is the environment that the creep method covers. All too commonly, crew or passengers survived the dynamic portion of the crash, only to suffer additional injuries or death when they are unable to safely exit the aircraft in a timely manner. The two primary factors in the causation of fatalities during otherwise survivable crashes is, post-crash fire and inability to quickly exit the damaged aircraft. Fire is the most significant post-crash hazard by a long shot. Not only can the fire kill and injure directly through heat, the toxic fumes and smoke produced when material and the aircraft interior burn are more often the direct cause of death. This post-crash condition is a top priority in controlling to prevent death. Design of airplane exits is predicated on the normal parked attitude and configuration. Obviously, this is not always the case. Sometimes occupants will have to exit from an airplane that is an abnormal attitude and perhaps in a very unusual configuration. Part 125 airplanes have specific emergency exit acquirements levied on them, many general aviation airplanes have only one exit which can be easily jammed in the airplane ends up inverted. In conclusion, nobody is expert on all types of structural failures. With so many different variables, it takes a highly detailed investigator to pinpoint what kind of failure causes a crash. And without a systematic approach of investigation of a crash, the investigators are left with an accident that is difficult to determine whether or not the occupants should have survived the impact.

Analysis Of The Musical Grease Film Studies Essay

Analysis Of The Musical Grease Film Studies Essay In this musical written by Jim Jacobs and Warren Casey, it is 1959 and Rydell high is crowded with defiant, fun-loving students. In the middle of this landscape, Sandy Dumbrowski arrives as the new girl in school. It turns out that over the summer she and Danny Zuko, leader of the Burger Palace Boys gang, have had a brief love affair. While Sandy tells her new classmates about the emotional involvement she had with Danny, he makes of tales about the sexual side of their relationship. As the show progresses the kids at Rydell High have to deal with issues surprising to people who have a romanticized view of the 1950s; love, gang violence, teen pregnancy, and friendship. In the end, Sandy and Danny work out their differences with each other and their friends and end up together and happy. I saw this production at the JSU/McClellan Theatre in Anniston, Alabama. The stage in this theatre is of the proscenium type. I think that overall, this is the perfect type of stage for this play but the arrangement of the theatre was a little lacking for this production mainly because of the seating challenges. There were three sections of seating. The middle section was fairly large and centered with the stage. There were two sections on either side that hugged the wall. The section on the far right was behind the orchestra. The orchestra pit was not really a pit and was actually on level with the seating. Therefore, those people in the rows behind the orchestra had a very difficult time seeing over the musicians and instruments; especially the harp that was used in this production. I know this because I was one of those unlucky enough to be sitting behind the aforementioned musicians. I spent the play with my head tilted at an odd angle trying to see around them. What I did have a good view of was the wing, stage left and unfortunately I could see the actors getting ready to make entrances and exits which ruined a little of the ambience. Had I been sitting in the center section and further back I believe it would have been much more enjoyable. This play had elements of the realistic and the non-realistic. It dealt with very real themes such as teen pregnancy, bullying, peer pressure, drinking, and gang violence. The non-realistic bits were obviously the musical numbers. In real life, we do not just burst into song because we broke up with a boyfriend or girlfriend or had a teenage romance. The sets of this play were not what I would call realistic. They attempted realism but it seemed as if the budget of the play and the way it had to be staged left them with no choice but leave it slightly abstract. The sets were very basic and the car set used for the Greased Lightning and Alone at a Drive-In Movie numbers was very cartoonish. The costumes in this play attempted realism but fell short. In the dance scenes, the dresses looked like leftovers from a 1980s prom sale that had been re-cut in an attempt to make them look like they were from the fifties. The clothing in the earlier scenes was a little bit better and closer to th e true fifties flavor. The use of props was done well. The actors used actual props for the most part, there was very little miming of actions. This play was a musical with elements of comedy. The comedy was mostly verbal with subtle inflections of tone. There were a few physical comedic elements mostly used by the characters of Eugene Florczyk and Cha-Cha DiGregorio, who did an excellent job making the audience laugh. The character of Jan played by Michelle Bain combined a few elements of physical with verbal comedy. Betty Rizzo, played by Judy Shealy was amazingly funny with her dry quips and very sarcastic delivery of Rizzos best lines. This play was structured episodically. This play was very entertaining. There were a few elements of it that could be taken as social messages such as the drinking and rebelliousness that resulted in a pregnancy scare for one of the characters. The playwright and director seemed to work in beautiful harmony for this production. You could see that there was a lot of effort put into the acting and the direction. The letter from the artistic director that was printed in the front of the program gave a small amount of background. For someone who was not familiar with the work it would have helped them to perhaps understand a little bit more of the motivation behind the play. There were several stand out performers in this play and also a few disappointments. Hands down Judy Shealys portrayal of Betty Rizzo was the show stealer. She gave the character real life. From the wisecracking to the sad and scared she made you care about what happened to her. Her performance of There Are Worse Things I Could Do was one of the standouts of the play. As I mentioned earlier the characters of Eugene and Cha-Cha played by Daniel King Jr. and Georgia Cook were wonderful. Both of these characters were very funny and entertaining. Jacob Cummings Teen Angel was excellent. The Teen Angel scene is one that I rank among my least favorites and it usually bores me, but I found myself loving this portrayal. Cummings sang excellently and lent a degree of humor to the role that was refreshing. Michelle Bain as Jan was another standout. She is a very good comic actress and her affected accent was very funny. I was not however thrilled with Heather Garlick or Joshua Cody Hunt who pl ayed the roles of Danny and Sandy. These are the two main characters and should carry the show. I found myself bored I am sad to say when they were on. Heathers performance as Sandy was wooden, one- dimensional and not at all believable. I found myself bored whenever she was on. Joshua Hunt as Danny was almost as bad although when he was interacting with the Burger Palace Boys he seemed to shine a little more. The scenery was low budget and it was obvious. It did detract a little from the overall performance. It was almost as if a high school had thrown the production together at the last minute as far as the scenery is concerned. The lighting was acceptable, but the band was excellent. They and the actors worked together well and there seemed to be no missed cues and everything flowed seamlessly. Overall, this was a very acceptable performance. The actors were as a whole very good, with the exceptions noted above. The band and actors worked flawlessly together and were very enjoyable. There was obviously a great deal of effort put into the choreography of the dance scene and it came off very well. It was a fun evening and certainly put a smile on my face. I came away nostalgic for a time I was not even alive to witness. Production Details Your name Cassie Patterson Name of production Grease Author Jim Jacobs and Warren Casey Producing organization or theatre where you attended Community Actors Studio Theatre Date of performance October 3, 2010 Style of performance (realistic, non-realistic, Combination combination) Structure of the play (climactic, episodic, ritualistic, Episodic Etc.) Form of the play (tragedy, drama, comedy, etc.) Musical Stage space (proscenium, arena, etc.) Proscenium Acting styles (realistic, melodramatic, exaggerated, Realistic, comedic etc.) Style of scenic designs (realistic, abstract, etc.) Abstract Style of costume designs (fantasy, abstract, etc.) Realistic Style of lighting designs (realistic, abstract, etc.) Realistic Production Personnel: Director Kimberly Dobbs Scenic Designer Eric Key Costume Designer Hayley Long, Lolly Payne, Sara Semmes Lighting Designer Terri Sherrill Stage Manager Pat Tiller, Chrissy Patterson, Cierra Parker, Tristan Waid, Janet Harbor, Tim Doyle, Alexandre de Lavalette

Repression of Women in Euripides The Bacchae Essay -- Feminism Women

Repression of Women in Euripides' The Bacchae      Ã‚   Many different interpretations can be derived from themes in Euripides's The Bacchae, most of which assume that, in order to punish the women of Thebes for their impudence, the god Dionysus drove them mad. However, there is evidence to believe that another factor played into this confrontation. Because of the trend of male dominance in Greek society, women suffered in oppression and bore a social stigma which led to their own vulnerability in becoming Dionysus's target. In essence, the Thebian women practically fostered Dionysian insanity through their longing to rebel against social norms. Their debilitating conditions as women prompted them to search for a way to transfigure themselves with male qualities in order to abandon their social subordination.    According to research, the role of women in classical Greece was extremely limited. Men and women were segregated all over in the Greek society, even in the home (Source 9). Women were secluded in their homes to the point of not being able to leave their own quarters except on special religious occasions or as necessity dictated (Source 10). All women were tightly controlled and confined to the home to insure that their husbands were provided legitimate male heirs. Beyond this, women had no true value (Source 6). Clearly, male domination in Greek society was like enslavement to women. A marriage contract dated 92 B.C. can be located in Women's Life in Greece & Rome by Mary R. Lefkowitz and Maureen B. Fant which defines unacceptable behavior within the union of marriage. The document requires that both husband and wife be chaste within the context of the household, but although nothing prevents ... ...because their position in life made them more susceptible to this kind of delirium.    Works Cited Williams, C.K. The Bacchae of Euripides Faraone, Christopher A. Ancient Greek Love and Magic Http://www.hup.harvard.edu/catalog/FARANC.html Gleason, Maud W. Making Men: Sophists and Self-Presentation in Ancient Rome Http://pup.princeton.edu/titles/5574.html Lefkowitz, Mary R. And Maureen B. Fant Women's Life in Greece & Rome http://uky.edu/ArtsSciences/Classics/wlgr/wlgr-greeklegal101.html Http://didaskalia.berkeley.edu/supplements/supp1/rabinowitz.html Http://novaonline.nv.cc.va.us/eli/eng251/agamemguide.html Http://pup.princeton.edu/titles/5665.html Http://www.classicnote.com/ClassicNotes/Titles/bacchae/themes.html Http://www.ifi.uio.no/~thomas/ai/ai03.txt Http://www.iwu.edu/~mblodget/hypergoddess.html   

Classroom Discipline and Management Philosophy Essay -- Classroom Manag

The goal in our classroom is to teach self-discipline, responsibility, cooperation, and problem-solving skills. Common causes of misbehavior include an attempt to meet unmet needs (belonging, significance, fun); a lack of needed skills (social and academic); inappropriate expectations; lack of structure; and a lack of sense of relevance. We will be focusing on non-punitive solutions to problems based on kindness, firmness, dignity and respect. True discipline comes from an internal locus of control (self-discipline), not an external locus of control (punishments and rewards inflicted by someone else). Some of the strategies used in our classroom will be proactive and some will be reactive. Many proactive strategies will be in place so that the use of reactive strategies is limited. These strategies include, but are not limited to: . Classroom Organization- Typically a Proactive Strategy although can be reevaluated as a Reactive Strategy- Classroom is thoughtfully designed to welcome all children, value everyone’s ideas and work, support active and engaged learning, support diverse developmental levels and learning styles, fosters independence, responsibility and cooperation, cultivates the care of materials and equipment, and gives students some choices in the learning process . Reinforcing teacher language- Proactive Strategy- Based on the idea of noticing what students are doing that we want them to keep doing; Names concrete or specific behaviors; Reflects important goals and values . Reminding teacher language- Proactive and/or Reactive Strategy- Reflects clearly established expectations; May be a question or a statement; Is brief and direct; is used when both the teacher and th... ... be sent to a â€Å"buddy room† to allow them a new environment to regain composure within) . Referral to Director, Assistant Director, or School Counselor- Reactive Strategy- Referrals to individuals outside of our classroom occur occasionally when o A Student’s behavior prohibits the class from moving forward in a productive way o If something occurs that the teacher believes needs immediate attention that cannot be given by the teacher at that moment o Others are perceived to be in danger References Nelsen, Jane. Positive Discipline. New York: Ballantine Books, 2006. Nelsen, Jane, Lynn Lott, and H. Stephen Glenn. Positive Discipline in the Classroom, 3rd ed. New York: Three Rivers Press, 2000. Responsive Classroom, Level II Resource Book. Turner Falls, M.A.: Northeast Foundation For Children, Inc., 2008.

Lenzs Law And Faradays Law Of Induction :: essays research papers

Lenz's Law and Faraday's Law of Induction 1. With this definition of the flux being , we can now return to Faraday's investigations. He found that the magnitude of the emf produced depends on the rate at which the magnetic flux changes. Faraday found that if the flux through N loops of wire changes by an amount , during a time delta t, the average induced emf during this time is This fundamental result is known as Faraday's law of induction. The minus sign is placed there to remind us in which direction the induced emf acts. Experiment shows that an induced emf always gives rise to a current whose magnetic field opposes the original change in flux. This is known a Lenz's law. Let us apply it to the case of relative motion between a magnet and a coil. The changing flux induces an emf, which produces a current in the coil; and this induced current produces its own magnet field. If the distance between the coil and the magnet decreases; so the magnetic field, and therefore the flux, through the coil increases. The magnetic field of the magnet points upward. To oppose this upward increase, the field produced by the induced current must point downward. Thus Lenz's law tells us that the current must move by the use of the use of the right hand rule. If the flux decreases, so the induced current produces an upward magnetic field that is "trying" to maintain the status quo. Let us consider what would happen if Lenz's law were just the reverse. The induced current would produce a flux in the same direction as the original change; this greater change in flux would produce an even larger current, followed by a still larger change in flux, and so on. The current would continue to grow indefinitely, producing power (=) even after the original stimulus ended. This would violate the conservation of energy. Such "perpetual - motion" devices do not exist. It is important to note, which I believe was forgotten in the class lecture, is that Faraday's investigation, as summarized in Faraday's law, says that an emf is induced whenever there is a change in flux. Thus an emf can be induced in two ways: (1) by changing the magnetic field B; or (2) by changing the area A of the loop or its orientation theta with respect to the field. A motor turns and produces mechanical energy when a current is made to flow in it. You might expect that the armature would accelerate indefinitely as a result of applied torque. Lenzs Law And Faradays Law Of Induction :: essays research papers Lenz's Law and Faraday's Law of Induction 1. With this definition of the flux being , we can now return to Faraday's investigations. He found that the magnitude of the emf produced depends on the rate at which the magnetic flux changes. Faraday found that if the flux through N loops of wire changes by an amount , during a time delta t, the average induced emf during this time is This fundamental result is known as Faraday's law of induction. The minus sign is placed there to remind us in which direction the induced emf acts. Experiment shows that an induced emf always gives rise to a current whose magnetic field opposes the original change in flux. This is known a Lenz's law. Let us apply it to the case of relative motion between a magnet and a coil. The changing flux induces an emf, which produces a current in the coil; and this induced current produces its own magnet field. If the distance between the coil and the magnet decreases; so the magnetic field, and therefore the flux, through the coil increases. The magnetic field of the magnet points upward. To oppose this upward increase, the field produced by the induced current must point downward. Thus Lenz's law tells us that the current must move by the use of the use of the right hand rule. If the flux decreases, so the induced current produces an upward magnetic field that is "trying" to maintain the status quo. Let us consider what would happen if Lenz's law were just the reverse. The induced current would produce a flux in the same direction as the original change; this greater change in flux would produce an even larger current, followed by a still larger change in flux, and so on. The current would continue to grow indefinitely, producing power (=) even after the original stimulus ended. This would violate the conservation of energy. Such "perpetual - motion" devices do not exist. It is important to note, which I believe was forgotten in the class lecture, is that Faraday's investigation, as summarized in Faraday's law, says that an emf is induced whenever there is a change in flux. Thus an emf can be induced in two ways: (1) by changing the magnetic field B; or (2) by changing the area A of the loop or its orientation theta with respect to the field. A motor turns and produces mechanical energy when a current is made to flow in it. You might expect that the armature would accelerate indefinitely as a result of applied torque.

Plant layout Essay

PLANT LAYOUT Outline of Contents: What is Plant layout? Necessity of good layout Factors affecting good layout Principles of good layout Advantages of good layout Symptoms of poor layout Types of layout What is PLANT LAYOUT? Plant layout refers to the arrangement of physical facilities such as machines, equipment, tools, furniture etc. in such a manner so as to have quickest flow of material at the lowest cost and with the least amount of handling in processing the product from the receipt of raw material to the delivery of the final product. Plant Layout is a plan of an optimum arrangement of facilities including personnel, operating equipment, storage space, material handling equipments and all other supporting services along with the design of best structure to contain all these facilities. A good layout is one which allows material rapidly and directly for processing. This reduces transport handling, clerical and other costs down per unit. Space requirement are minimized and it reduces idle machine time and idle time of man. Necessity of good plant layout Minimization of material handling Optimum utilization of available floor space Elimination of bottlenecks through balancing of all capacities Minimization o production delays Easy supervision and better manpower resources through elimination of idle time Elimination of physical efforts required by workers Elimination or improvement of objectionable operations. E.g. Operations with bad odor, vibrating operations etc. Avoiding industrial accidents Better working conditions like light, ventilation, noise control etc. Optimum utilization of machinery and equipment through proper use. Minimization of cost so that product will be available at cheaper rate to customer and  delivery in time. Factors affecting facility Layout Nature of plant-Engineering/Process Industry Type of Production-Mass/Flow, Batch, Job Shop Type of Production-Make to Stock/order, std/spec Plant Location-Area available, building type-storey Volume of Production-Scale of production Types of machines and equipment-automation Repairs and maintenance -Policy, schedule on site Arrangement of material handling equipment Future expansion plan Principles of good Layout Minimum Handling Interdependence Minimum investment Integration of factors-3M Minimum movement-Distance/Flow Continuous flow-forward Optimum utilization of available space Maximum visibility Maximum accessibility Maximum Flexibility Safety, Security and Satisfaction Advantages of Good Plant Layout Proper and efficient utilization of available floor space Transportation of work from one point to another point without any delay Proper utilization of production capacity. Reduce material handling costs Utilize labor efficiently Reduce accidents Provide for volume and product flexibility Provide ease of supervision and control Provide for employee safety and health Allow easy maintenance of machines and plant. Improve productivity Symptoms of Poor Layout Delays and work stoppage in manufacturing process Slow movement of material through the plant Congestion of materials, components and work in progress Poor utilization of space High material handling and transportation costs Excessive handling by skilled workers Production cycles and delays in delivery Mental or physical strain on operators Difficulties in maintain effective supervision and control Underutilization of machines and workers Lack of flexibility and difficulty in production planning and control Types Of Layout: There are mainly four types of plant layout: (a) Product or line layout (b) Process or functional layout (c) Fixed position or location layout (d) Combined or group layout Product or line layout: In this type of layout the machines and equipments are arranged in one line depending upon the sequence of operations required for the product. It is also called as line layout. The material moves to another machine sequentially without any backtracking or deviation i.e. the output of one machine becomes input of the next machine. It requires a very little material handling. It is used for mass production of standardized products. Advantages of Product layout: Low cost of material handling, due to straight and short route and absence of backtracking Smooth and continuous operations Continuous flow of work Lesser inventory and work in progress Optimum use of floor space Simple and effective inspection of work and simplified production control Lower manufacturing cost per unit Disadvantages of Product layout: Higher initial capital investment in special purpose machine (SPM) High overhead charges Breakdown of one machine will disturb the production process. Lesser flexibility of physical resources. Process layout: In this type of layout the machines of a similar type are arranged together at one place. This type of layout is used for batch production. It is preferred when the product is not standardized and the quantity produced is very small. Advantages of Process layout Lower initial capital investment is required. There is high degree of machine utilization, as a machine is not blocked for a single product The overhead costs are relatively low Breakdown of one machine does not disturb the production process. Supervision can be more effective and specialized. Greater flexibility of resources. Disadvantages of Process layout: Material handling costs are high due to backtracking More skilled labour is required resulting in higher cost. Work in progress inventory is high needing greater storage space More frequent inspection is needed which results in costly supervision Combined layout: A combination of process & product layout is known as combined layout. Manufacturing concerns where several products are produced in repeated numbers with no likelihood of continuous production, combined layout is followed Fixed position or location layout: Fixed position layout involves the movement of manpower and machines to the product which remains stationary. The movement of men and machines is advisable as the cost of moving them would be lesser. This type of layout is preferred where the size of the job is bulky and heavy. Example of such type of layout is locomotives, ships, boilers, generators, wagon building, aircraft manufacturing, etc. Advantages of Fixed position layout: The investment on layout is very small.  The layout is flexible as change in job design and operation sequence can be easily incorporated. Adjustments can be made to meet shortage of materials or absence of workers by changing the sequence of operations. Disadvantages of Fixed position layout: As the production period being very long so the capital investment is very high. Very large space is required for storage of material and equipment near the product. As several operations are often carried out simultaneously so there is possibility of confusion and conflicts among different workgroups.

Black Panther Party during the 1960s Essay

The Black Panther Party was a left-wing organization founded in 1966 for the defense of African Americans (Katsiaficas, and Cleaver 3). It was founded in Oakland, California by Bobby Seale and Huey Newton and would go on to gain fame all over the United States for its deep commitment to defend the rights of the African American population as a minority group (Katsiaficas, and Cleaver 3). For the decade it lasted, the Black Panther Party was able to tackle one of the most pertinent issues of the time: Racism. In this essay, I seek to explain the role the Black Panther Party, whose initial objective was to defend African Americans from police brutality, played in American society in the 1960s. Black Panther Party began as a result of a prior history of activism where African American opinion leaders were pushing for equality and an end to racial prejudices and police brutality (Katsiaficas, and Cleaver 71). African Americans had for long demanded that authorities address the issues that were affecting them as a minority in the American society. The Black Panther Party the discipline and calmness preached by renown African American activist Malcolm X to become the heroes of the African American cause (Smethurst 21). The party symbolized self determination and pride, and initiated programs aimed at educating African Americans politically as an attempt to achieve a revolution in diction, the free spirit and commitment to the cause. It became a symbol of African American culture and even had an impact on fashion. The Black Panther Party, through its Ten Point Program, was able to grasp the attention of the authorities and the American public about the issues that were affecting the African American community (Katsiaficas, and Cleaver 76). It gave an outcry about the oppression that was perpetuated against members of its target community and their lack of control in the political and social institutions that were meant to serve them. The party also petitioned the government and demanded it honors its obligation to provide employment or guarantee an income for all people (Katsiaficas, and Cleaver 76). The other demands in the Ten Point program included a call to end economic exploitation of the African American and other minority communities and the honor of the promise for forty acres of land and a mule that had been made 100 years earlier as reparation for slavery (Jones 177). The party also demanded better housing to be made available in African American neighborhoods failure to which the land should be made cooperative land so that African Americans could build their own decent housing. The Black Panther Party managed to petition authorities about the poor quality of educational infrastructure in African American neighborhoods as well as pushing the agenda for free healthcare for impoverished Americans (Jones 179). Police brutality was rampant in those days, targeting African American and Hispanic men. The Black Panther Party wanted an end to all this; and through sensitizing the public, it helped create an awareness and knowledge of human rights which was later to become instrumental in later activism (Smethurst 26). The Black Panther Party followed the ideals of Chinese revolutionary leader Mao Zedong as he outlined them in his manual, The Little Red Book, to orchestrate economic and social awareness campaigns among African American people through what it called Survival Programs (Katsiaficas, and Cleaver 81). Through these programs, it fought drug abuse and rehabilitated drug addicts, organized free medical clinics and offered emergency response and ambulance services. In addition it founded the Inter-communal Youth Institute with Ericka Huggins as the director to demonstrate how African American youth must be educated so that they would be empowered politically and economically (Katsiaficas, and Cleaver 81). There were also other programs, most of which had an impact on live in areas where the party was operational. The Black Panther Party had an impact on the political landscape during the time it existed. The party assumed the role of teaching African Americans their political rights and their guarantees as legal American citizens to basic human rights, individual freedoms and liberties (Jones 178). To be more effective, it briefly combined efforts with the Student Non-violent Coordinating Committee which was headed by Stokely Carmichael who later renamed himself Kwame Ture in line with his Pan African ideals (Jones 178). This was just after it was founded. In the year 1967, the Black Panther Party organized a street march in which many African Americans were involved in a procession to the California State Capital to oppose a proposed directive to ban the carrying of loaded weapons to public places (Katsiaficas, and Cleaver 81)). The panthers (members of the party) had already begun exercising that right; and on this procession they all carried rifles. The Black Panther Party sought to empower African Americans politically; and having garnered widespread support from African Americans and other sympathizers, its Minister of Information, Eldridge Cleaver ran for president in the 1968 presidential elections (Katsiaficas, and Cleaver 85). The party made a bigger impact than its opposite, the White Panther Party. Its biggest role was perhaps in the human rights movement. Even though the party lasted for only 14 years, it left a lasting impression on the struggle for rights and equality, and its ideals of community service are still present in many African American communities today. Works cited Jones, Charles. The Black Panther Party (Reconsidered). Baltimore, MD: Black Classic Press, 1998. Katsiaficas, George, and Cleaver, Kathleen. Liberation, Imagination and the Black Panther Party: A New Look At The Panthers and Their Legacy. New York: Rutledge, 2001. Smethurst, James. The Black Arts Movement: Literary Nationalism in the 1960s and 70s. Chapel Hill, NC: University of North Carolina Press, 2005.