Leftside bias and Holistic effect in face recognition Lab Report

Leftside bias and Holistic effect in face recognition - Lab Report Example One hundred twenty trials were done for each orientation (Upright: Left or Right and Inverted: Left or Right), that is 120 upright images (60 adult and 60 baby images) and 120 inverted images (60 adult and 60 baby images) were shown to the participants. Group data was analyzed using T - test. Results showed a significant difference (p Participant's T-test (two tailed, independent sample) was performed to compare the mean probability of the study group with the null hypothesis (i.e. probability of the participants holding the left-left face as the original face whether the image is upright or inverted is 0.5). In this study, 120 trials were done. Therefore to analyze the group data N = 60 was considered and to analyze individual data N = 120 was considered. For statistical calculations probability of null hypothesis was taken as 0.05. To find out if there was any significant difference between the two groups in terms of chimeric face chosen (left-left or right-right) with respect to how the images are positioned (upright or inverted), an Independent T - test was done. Table 2 and 3 shows the results of the T - tests (also the Descriptive Analysis is shown). Table 2 Descriptive Analysis The Descriptive Analysis showed that greater than 50 percent of the participants chose a left-left chimeric face. This result is in resemblance of the 'left-side bias' observed by Hsiao and Cottrell (2009). Table 3 T-test Results The t-test results revealed a significant difference of participants choosing a left-left chimeric face on both upright and inverted images. Discussion This study was carried out to identify whether the orientation of images upon presentation has a significant effect on the decisions made participants of the facial likeness task. One hundred twenty trials were done for each orientation (Upright: Left or Right and Inverted: Left or Right), that is 120 upright images (60 adult and 60 baby images) and 120 inverted images (60 adult and 60 baby images) were shown to the participants. Group data was analyzed using T - test. To find out if there was

Is Childhood Discipline Effective Research Paper

Is Childhood Discipline Effective - Research Paper Example The essay would hereby initially trace the historical background of using corporal punishment, particularly smacking, as a tool for childhood discipline. In addition, the discourse would present a general overview of different positions or contentions on the issue of smacking as the most effective technique for childhood discipline. Finally, the concluding portion would highlight the crucial points discussed and present a speculation and recommendation on the most effective tool for childhood discipline in the future. Relevant History and Background The roots of corporal punishment could be traced from the earliest published article in a periodical, the San Francisco Call, dated March 23, 1893 entitled â€Å"Slap or Spank?: School Punishment Query in Alameda† where the School Board of Alameda supposedly sought to determine the manner by which parents would agree and stipulate the kind of chastisement to be used to discipline the children (corpun.com 1). At that time, the conte nts of the article generated different reactions and responses from school administrators, teacher and parents; with the final recommendation that â€Å"the general verdict of all those seen is to the effect that the spanking process is far superior to the regulation strap method, but all concurred in saying that the best way of all in such matters was to leave it entirely with the teachers, who should be kept within bounds regarding the severity of the punishment inflicted by rules laid down by the Board of Education† (corpun.com 1). Suffice it to say that even at the earliest published article on corporal punishment through spanking or smacking, the issue was elicited diverse and conflicting arguments. Some parents averred that they do not want their children to be spanked at all. Other parents support smacking on prescribed areas of the body, but never on the face. And still, surprisingly, one parent remarked that â€Å"’taken across the knee and spanked, by all me ans. That's the old way, and I have found it very efficient.’ And the obedience of the little ones clustered about her was good evidence of the truth of the statement† (corpun.com 1). These diverse reactions have evolved through centuries and until contemporary times, smacking continues to be a controversial issue. In current times, Gershoff and Larzelere disclosed that, â€Å"corporal punishment remains a widely used discipline technique in most American families, but it has also been a subject of controversy within the child development and psychological communities† (par. 1). The controversial nature is clearly depicted from the contradictory arguments advocated by parents, to wit: â€Å"The consultation document issued this month by the Department of Health on the physical punishment of children states clearly that ‘many parents would welcome support in learning effective measures of disciplining their child which do not involve physical punishmentâ₠¬â„¢ while adding that ‘there may still be occasions when parents †¦ may consider it appropriate to discipline a child through physical punishment’† (Waterston 261). In this regard, parents, social workers, health professionals and policymakers all provide different perspectives on the subject of corporal punishme

Multidimensional Chromatography Essay Example | Topics and Well Written Essays - 2000 words

Multidimensional Chromatography - Essay Example Hence, essentially speaking, one dimensional chromatographic separation is definitely not the last word for isolation and characterization of biomolecules, chiefly proteins. The limitation is due to its low resolving power in presenting a homogenous protein sample from a complex mixture of several other unwanted proteins, associated matrix components and metabolites that can otherwise be segregated in a much more efficient way by various types of matrix loaded multiple columns utilizing their differential properties and affinities. Moreover, combination of two or more analytical separation steps involve perfectly standardized pre-treatment processes that are to be coordinated in an automated way for a complete segregation of the test samples. (Mondello, P. 251) Multidimensional separation techniques were first devised with the implementation of two dimensional separation beds, in which two different parameters for migration corresponding to two distribution coefficients help to identify the separated components on the bed with more certainty and a high peak capacity than that achieved by one dimensional separation procedures. (Cortes, P. 14 - 15) A high value of peak density is an important requisite for effective separation process and it can easily be achieved by combining two or more chromatographic separation techniques. The greater the number of peaks that can be resolved effectively in a given multidimensional separation procedure within a fixed time frame greater is the overall efficiency of the process. Likewise with effective resolution of a higher number of peaks more and more complex samples can be duly segregated, characterized and analyzed for further investigation. In a simple two dimensional chromatographic process that is c arried out by a combination of two different columns, the maximum peak capacity will be the product of the peak capacities of the individual columns, thereby generating a higher capacity of resolution for the overall analytical process. As for example, the peak capacities for each separation process being 100 and 200, the combined value of the maximum peak capacity of the two dimensional separation procedure becomes a product of the two, that is, 20000, thereby ensuring high resolution and larger separation between the collected fractions. (Chromatography Online.com, 1998 - 2008) Multidimensional chromatography, therefore, finds a maximum usage in biomedical research and especially in proteomics, where investigation of biological samples of protein mixtures requires prior separation and characterization in order to tag the target protein. In protein analysis research several novel methods of multidimensional chromatographic separations are being currently used in complementation with the 2-D polyacrylamide gel electrophoretic separation (2D-PAGE), for a much better resolution and greater separation space between analyzable eluents. Multidimensional approach involving multidimensional liquid chromatography (MDCL) used in unison with bio-mass

IPad's Security Breach Essay Example | Topics and Well Written Essays - 1000 words

IPad's Security Breach - Essay Example Subsequent to this breach of AT&T’s security, a lot of security issues have since arisen for the firm and other computer security firms. In addition, many interested parties have questioned the justification of hacking activities as well as the role of ethical statements and policies of computer security firms, which promote activities such as website hacking. This paper explores the subjects of the possibility of the justification of hacking, computer security firms’ ethics that promote hacking, and the social responsibilities of media firms such as Gawkers Media LLC. Justification of Hacking into Websites Most hackers state that they hack into websites not as criminals but as interested parties seeking to identify flaws in computer systems or reveal certain information. By hacking, they claim, it becomes possible for computer security firms to prevent or rectify any damaging security leaks. However, due to the side effects of hacking and the damages it causes to compu ter firms’ images and business, questions have a risen on the issue of justification for hacking and activities. While others insist that hacking can never be justifiable, others believe it is a justifiable practice, depending on the reasons for which it is done (Harper’s Forum, 1999). ... peoples’ data worldwide, hackers believe they compel these companies to ensure that they have tamperproof systems that keep their clients’ data confidential. Therefore, hackers are watchdog for the public on the security weaknesses of technology firms. Hacking is thus justifiable since it addresses the vulnerabilities inherent in technology products that expose clients’ confidential information (Harper’s Forum, 1999). Hacking could also be justifiable if its exposes illegal political activities by discredited groups. In addition, hacking may be justified if it reveals certain publicly important information, which the public is denied by governments, organizations, or politicians. Importantly, hackers reveal malpractices and criminal activities that may be happening without the knowledge of the public and the law enforcement agencies. That is, when a hacker discovers the criminal operations of certain individuals or organizations and such reports are sent t o law enforcers, that hacking is certainly justified since it benefits the society and does not harm the public or any private person in any way (Harper’s Forum, 1999). Various factors have been found to promote hacking activities. Among these factors are the various ethical statements by computer security firms. Corporate Ethics Statement That Promote Hacking The ethical issue regarding the freedom to access information is perhaps the number one motivator of hackers to indulge in their activities. In fact, the ethic on which hackers justify their actions is that they investigate issues, allowing every individual in the society to gain information and knowledge on the various hidden issues affecting their lives (Ermann, 1997). Once a corporate computer firm issues ethical statements that emphasize the

The Badja Essay Example for Free

The Badja Essay Introduction: The Badjao – which literally means fisherfolk or simply fishermen – is a group of indigenous people that are usually referred to as â€Å"Sea Gypsies,† making use of small wooden boats known locally as â€Å"vinta.† In their houseboats, also known as â€Å"Lepa† and â€Å"Pelang,† they usually carry all their belongings and valuables as they travel from one place to another. According to Dr. Pendatun I. Talib, Secretary General and Founder of the National Sama-Badjao Movement, Inc., and currently director of the Bureau of Fisheries and Aquatic Resources-Regional Fisheries Training Center in the Zamboanga Peninsula, the children of the Badjao people feel more at home whenever they are aboard their vintas because of their ties with the sea – having been at the sea. Objectives: To know the Badjao’s way of living To know how they live in their current places To know their basic daily routine, traditions, beliefs, and practices Hypothesis: If I would continue my research about the badjao’s, then I would know their way of living. Significance of Study: If I would continue my research and studies about this, it would: Change not only my way but also other people’s way of treating the badjao people. Change my first impression on ethnic groups like the badjaos. Let me know the way how they live and how they kept alive their culture. Let me know the traditions, routines, practices, and beliefs of the badjao people. Conceptual Framework: Definition of Terms: Badjao in its origin simply means Man of the Seas â€Å"Vinta†, small wooden boats known locally. â€Å"Lepa† and â€Å"Pelang,† other term for houseboats. The patadjung/tadjong has many uses. Among the Badjao it is large enough to fit any person and is worn by both men and women as a skirt or gown tucked at the chest level.It can serve as putung (headcover), waistband, sash, blanket, hammock, shoulder bag, cradle, pouch, hood, or pillow. A simpay (band) forms the front opening and extends to the back from a small collar. The gallang (bracelet) is the most popular ornament. Lampblack is used to outline a rectangle on her forehead and this is emphasized by yellow ginger juice. The leleng is sung for any occasion, by anyone of any age. It is also sung for special occasions like weddings, haircuts, or circumcisions. Binoa is similarly chanted as the leleng. Igal or pangalay, performed by the female, is the basic traditional dance movement. Pag-Omboh – A ritual that traces its origin to the Pre-Islamic times, it is observed by the people who believe that performing it is necessary to ensure a sense of well being and to preserve the harmony between the material and spirit worlds. This practice is usually done when illness/death strikes the family. This misfortune is seen as a sign of the patient having offended or displeased a spirit; Pag-Jinn – It is an opportunity for the faith healers and shamans to commune with the spirit to help sustain and enhance their healing powers. It captures the depth of animism that is an integral part of the belief system of the people; Pag-Diwata – it is characterized by intense and frenetic ritual dancing to the tune of the Agong and Kulintang; Pag Tulak Balah – It is a water ritual of symbolic cleansing; Pagtimbang and Paggunting – The child is placed on a weighing scale traditionally made of a wooden pole with Patadjong, wherein ritual goods equal to his or her weight are placed. While the Paggunting is traditionally held to coincide with the Maulidin-Nabi, the day when the Holy Prophet Muhammad was born; Pag Tammat – One way to achieve this is through the Pangadji series of tutorials with the local guru or imam, who inculcates the importance of the Holy Qu’ran into the life of the learner; Pagkawin – A wedding begins with the Magpahanda, the formal presentation of a marriage proposal with a request for parental consent. The Mahal (dowry) is brought to the bride’s house. The marriage is solemnized with witnesses with duwa’a (prayer), hutbah nika (counseling), and ends with â€Å"pagbatal,† or when the groom touches the forehead of the bride with his thumb; System of Pag Kubol – The body is bathed amid prayers, it is then shrouded with a new white cloth followed by the Sambahayang Mayat (prayer) to be led by an Imam. Pagkubol must take place within 24 hours of death; Putikaan – Consulting the Putikaan for the auspicious time to set out for any activity or voyages ensures success; and, Hinang-Hinang (Barang) – An Spiritual Act that causes harm to other people using some needle materials, scissors, and egg, or maybe using some other objects.

Evaluating a Torsional Pendulum Experiment Essay Example for Free

Evaluating a Torsional Pendulum Experiment Essay I will firstly work out the overall experimental error and how far it was from the true value, using the same formula used in the preliminary. =2? = 10.36 Therefore the total error from what the true value should be is [(11.368-10.36)/11.368] x 100= 8.89% This shows that my experimental results had an overall 8.89% error, where as in my preliminary I had an error of 15.89%, therefore I believe my improvements have improved the accuracy of my results. From the 2 graphs above I can see that the result for 0. 1 meter length seems to be the furthest away from the line of best fit, and may be considered as an anomalous result, however I dont think its necessary to remove this result. The reason for this error could be any of the ones stated below, or possibly as it was the first reading I took, there could have been an initial fault in my experiment set up. Even though I have improved the accuracy of my experiment there are still many errors which will have decreased the accuracy of my results. I will now state each one and estimate percentage errors for the reading error and also experimental error if possible. * The meter ruler is accurate to à ¯Ã‚ ¿Ã‚ ½0.5mm, therefore error on the smallest length would be (0.5/100)x100=0.5% and largest length (0.5/500)x100=0.1% . Therefore the error here can be no greater than 0.5%, so this is not a very significant error. However there is also a large span for experimental error, the length of string may not have been fully straight due to not being stretched fully, and also every time I change the length of the wire there will be a new random error generated. These cant be avoided but overall these experimental errors may have been about à ¯Ã‚ ¿Ã‚ ½0.3cm , meaning the maximum error would be (3/100)x100=3% error, which is therefore very significant. * The micrometer is accurate to à ¯Ã‚ ¿Ã‚ ½0.005mm, therefore the error on my diameter of 0.49mm was (0.005/0.49)x100=1.02%, this shows a reduced error that of the preliminary, however a 1% error on the diameter can still be a major factor. This is due to the fact that the diameter is raised to the power of 4 in the equation. Therefore a very small change in the diameter may cause a larger than expected change in time period. Therefore I think the error of the diameter may have been the most significant error. If the diameter had been 0.48mm then the percentage error calculated above would have been only 5%, this shows how significant it was. The experimental error is also a factor due to the fact I had to twist two wires together to make a larger diameter. After taking 5 readings of the diameter, which were 0.49, 0.49, 0.48,0.49,0.47mm. I decided to use 0.49 as my value being the mode, however the fact that the diameter varied slightly meant there was an error. The range was 0.02mm, this could therefore have caused an error (0.02/0.49)x100=4.08%, therefore also very significant. Also the fact that I twisted two wires together, after some use, parts of the wire may have untwisted meaning the diameter would change again, this again contributes to the error above. One of the major improvements was the recording of the time period. Using the light gate and an interval of 0.01seconds, the error was only to à ¯Ã‚ ¿Ã‚ ½0.005seconds therefore the maximum error was (0.005/4.15)x100=0.12% and smallest error (0.005/8.40)x100=0.060%, this shows the improvement in recording the time period, where the human error is eliminated. However one small difficulty in taking the actual reading was knowing where to take the intervals. However there was also an experimental error where I had to estimate where the middle of the peak was, and this was slightly different for each run. However the peak was never longer than about 0.1 seconds, therefore the largest error would only have been (0.1/4.15)x100=2.4%. Again the experimental error is greater than the reading error, but the overall error was much lower than the preliminary. * The value for shear modulus I used was 44.7x109GPa, however when doing research for this value, there were more than one of the same value, so there is no guarantee that the value I used was the value of my copper wire. The following website gave me a range of 40-47GPa. http://www.efunda.com/materials/common_matl/common_matl.cfm?MatlPhase=SolidMatlProp=Mechanical However, as the shear modulus is so large the error will be so small. Its difficult to work out the percentage error, therefore my error is just a range of 40-47GPa * The scale is accurate to à ¯Ã‚ ¿Ã‚ ½0.05 grams so error on my bar was (0.05/196.3)=0.0254% error, there is no real experimental error in this reading. The percentage errors above show that the overall error should have decreased, where time period is now a very small error, reduced from about 8% in the preliminary. From my log log graph I got 0.4532 as my gradient. However theoretically it should have been 0.5. I also found that if I exclude the 0.1meter length and time period from the log log graph then my gradient would change from 0.4532 to 0.4963, which is very close to 0.5. This again shows that the 0.1m length may be considered as an anomalous result. To work out the percentage error for the gradient, I have to consider the error on the time period and the length, by adding these errors. Therefore the error on the gradient is approximately [{(0.5+3)/2}+{(0.12+2.4)/2}]=3.01%, this was using the average of the reading and experimental errors. From the percentage errors above I believe the main source of error was the diameter of the wire, this had the highest total percentage error and as seen from the equation any error in the diameter will cause a major difference due to being raised to power 4. Reliability of results Time Period(seconds) Experiment Results T=11.368 x l^0.4532 T=2?(I/K)^0.5 Difference1 Difference 2 4.20 4.00 3.27 0.19 0.92 4.65 4.81 4.01 -0.16 0.64 5.23 5.48 4.63 -0.25 0.60 6.16 6.06 5.18 0.10 0.99 6.51 6.59 5.67 -0.07 0.84 7.10 7.06 6.13 0.04 0.98 7.50 7.50 6.55 0.00 0.95 8.04 7.92 6.95 0.12 1.09 8.38 8.30 7.32 0.07 1.05 The table above shows my actual experimental results in the first column. Then the expected experimental result using the relationship I found in the second column. The third column is the theoretical result using the equation derived in my research. The forth column shows the difference between the values I obtained in my experiment and the expected values from the relationship I determined through experiment. And as you can see the maximum difference is only 0.25 seconds away. Therefore this relationship has very strong correlation, as shown on the previous graphs. However, in the fifth column, which shows the difference between my experimental value and the theoretical value according to the equations I noticed that I was constantly above the expected value. Also I was constantly about 1 second above for almost every length measured. From this I came to the conclusion that there must clearly have been some sort of systematic error. This will have increased the time period by approximately a constant amount each time. From my error analysis earlier I believe this may have been the diameter of the wire, as even being 0.1mm away from the true value will cause a large change in time period, which is what may have happened. Improvements to final method If I was to perform this experiment again I would try to further decrease the reading and experimental errors in the following ways. * As I found diameter to be the largest error I would ensure that the wire I am using has a constant diameter, by using only one wire and ensuring it has not been stretched in any way before using it. I would then also measure the diameter of the wire at least 5 times for each length, as when the length is decreased the weight will be pulling down on a wire of shorter length, and may stretch the wire more. Therefore I will record the diameter for each length I do and if it changes take these new diameters into consideration. * The shear modulus of copper ranged from 40-47GPa, therefore I was unable to even come up with an actual error for this. Therefore to reduce the error to almost zero I would measure the actual shear modulus of the copper wire I am using to do the experiment. This can be done using the following formulae G = E / [2(1+?)] where G is the shear modulus, E is the tensile modulus, and ? is the Poissons ratio of the material.

Materials for Constructing a Multi-Storey Bulding

Materials for Constructing a Multi-Storey Bulding When dealing with a multi-storey building it is important to get the right materials as these materials will hold the structure together, the multi-storey building itself is very large and will be constantly in use as it is a hotel so the building will be subjected to different loads and situations. Loadings on beams, columns, frames, pads and floors can cause many structural differences the behave and performance of the material may change due to stress and strain on them, the materials I am going to look at are steel and concrete, these materials are used throughout the construction industry and loads on these materials are important as if the material is not up to the job and does not fulfil the need the beam, column, frame, pad or floor could collapse and cause many injuries and be a health and safety danger so it is important to use the materials in the right way. both materials steel and concrete have the advantages and disadvantages when used, when dealing with a multi-storey building it is important that the material can withstand the pressure it is put under so it would not collapse or break, if this does occur the knock on effect would result in the building to collapse and cause large injurys to civilians within and around the building, to stop this the materials which are used and put under a subject of tests such as being compressed and stretched rapidly any faults such as the material does not meet to the UK standard would be out lined and amended or discharged from use on site, this is also done for health and safety reasons. First looking at concrete it is used often through put construction it is used due to its durability and workability, to get to a workable mix the concrete needs to be cured and portioned first, it is important that the concrete meets the needs this could be the concrete is used to construct a concrete beam and this beam is put under a lot of loads; therefore the beam would need to be able to receive the load and distributed. Every material has Strength this is the ability of the material to resist the forces set up within them by the applied load, when a load is applied movement is made so therefore Stability is needed stability is the ability of the structure to resist overall movement, any load (force) tends to move to a downward direction for the material to keep to its state it should maintain a equilibrium this is done by the material resisting the equal and opposite force, any load that is applied is called a active force, this force can also be distributed this is when the load is applied over full length or area of a structural member this would be used in a pad foundation, also other loads may be called can be concentrated or point where the load is put to a single point or over a very restricted area this is used with conjunction of columns and beams. When the load is put to a material in a form of a beam, column, frame, pad or floor the structural material may be affected in the following ways: Stretch called the tensile force, tend to stretch the material Compress called the compressive force , which tends to squeeze a material Shear force when the force causes one part to slide past the other force which tends to make surfaces of a material slide. Torsional force causes the member to twist If the load is not distributed this can result in the beam could form cracks and collapse due to the load it is receiving this works in vise versa if the beam is being crushed for example the building could encounter an earth quake and the beam is being crushed the beam needs to withstand this to help keep the structure of the building; so therefore tests are made up such as a crushing test this is at the stage where the concrete is being made/ produced (mixing/curing), the concrete is mixed and cured (curing can take weeks) depending on the ratio used in the mix, the crushing test is the mix is set into cubes and at different curing stages, each cube is put under a load at which could be put on the multi-storey structure, once the results of each cube are collected the results are analysed and then a decision is made in which grade of concrete to work with for the build, the formula for the test is: These tests are made to find of the: Shear forces Bending moment Deflected shape Reactions at supports As you can see from the example I have given as time goes on the crunching load has increased, this shows that the concrete cube has become more diverse in strength by every week, from these crushing loads the different concrete grade can be used at different points in in construction. Stress is derived by dividing the load applied by the cross-sectional area of the member Stress (f) = Load/ Area = W/A= N/mm2 Strain is measured by dividing the change in length by the original length Strain = change in length Original length The purpose of beams, columns, frames, pads and floors are to: Resist loads imposed upon it. Transfer loads to the foundation. Provide vertical and lateral stability to the structure. Resist bending. A  Beam  is a horizontal structural member resting on  two  or more supports. Beams can be in many forms such as: Simply  supported   where the beam is resting on two supports. Fixed where the ends firmly built in and do not move Cantilever   where one is   firmly built in at one end and the other end is free Continuous   where the beam is resting on three or more supports. A  Column  is a vertical structural member used in the construction industry to transmit  imposed loads  to other members or to the foundation. Compression, Tension and Shear   When the force on a structural member stretches called the tensile force tends to stretch the material. When a force squashes or compresses the member, this is called compressive force , which tends to squeeze the material When the force causes one part to slide past the other force which tends to make surfaces of a material slide. This is called a shear force Bending, Buckling and Deflection this is most common in columns, columns are mostly made of concrete or steel due to their strength properties, timber may also be used but if a large load it put on the Colum buckling could occur (bend sideways).   A beam could be affected by defection if a large load is put on it, the beam could be made of either steel or timber.   A  bending moment  is occurs when the material resists a force this occurs with beams. concrete is a mixture of cement, fine aggregate, course aggregate and water when these are mixed at a good ratio to each other when set it will form a hard solid mass or artificial stone, there is a rule which is used in construction the greater the proportion of cement, the stronger strength of the aggregate , but the water content in the cement is important this process happens in curing the cement over a couple of weeks, as there is more water the cement may not be able to be at its full strength, due to the strength, workability and density of concrete it can be easily made and humans have the ability to create concrete with very specific properties, therefore this material is used allot in design and construction where the manufacture produces a mix when set concrete produced will have desired properties needed. The multi-storey building is made of concrete would consist of: Slabs Columns Shear walls Foundations Reinforced concrete suspended floors Ribbed floors Hollow pot floors Beams Precast concrete floors Concrete is easy to maintain, the first and up most important thing to do is to allow proper curing of the mix as this will allow maximum design characteristics of the concrete mix to be achieved, the concrete when set can be covered in a water resistance paint this will protect the set concrete from water as water is concretes worst enemy; if water sits on the concrete this can stain the surface, allow cracks to form and mold spores to develop making the concrete slippery, this could cause major defects in the construction itself,  the most important thing is to look at temperature when dealing with concrete as concrete can expand and contract, which can force cracking and leave the concrete exposed to increased water intrusion so if crakes do occur these should be filled in and dealt with straight away. Concrete helps to minimise the amount of energy that a building consumes and ensure that the building maintains a level of thermal comfort that is appropriate for its occupants. C oncrete helps buildings to achieve this, as a heavyweight material, concrete acts as a store (or buffer) during the heating season by utilising free heat gains, concrete can It can only be renewed if it is crushed down and grinned into sand. Steel is made up of alloy of iron and carbon, steel can be very useful to the industry of construction, it is used from protective shoes to large beams to small nails, the material is so versatile due to its melting and strengths properties but yet it is lightweight for easy handling this means economical shipping. Precise measurements can be taken meaning very precise cuts of steel can be made so less wastage is made, steel acts as Great protection against the worst weather conditions, Installation is fast and simple, Steel is also recyclable so it is environmentally friendly the steel can be easily malted down and re used for another purpose, to maintain steel it would need to be cleaned regularly and checked for any defeats, when using steel in construction it is important to take in account energy efficiency; if a whole home was built of steel it would be less energy efficient than a wooden house, insulation would be needed to keep in heat this is because metal transfers heat to a colder area more quickly than wood sometimes up to 400 times more rapidly steel studs can create a thermal bridge to the outside of the house, to stop this when the house is being constructed the steel can be warped in insulating board this would help to keep in heat and reduce the thermal bridge, but also one adv antage of steel is the fact that steel can be recycled with ease it can be melted down with not a lot of hassle and the steel can be used to make other things. The sustainability of steel is very good as this material allows, rapid construction on site (therefore reducing site activity) and disruption to neighbors, steel can be precut and delivered in so a system called just-in-time can be used this will reduce site congestion, steel structures are inherently adaptable and extendable, and also steel is multi-cyclable, being 100% recyclable without down cycling. Steel is located in the ground so it would need to be dug out to be used as it is made of carbon and iron, When it is all finished there will be no more. That is why recycling steel is so important. Steel is widely used in construction, due to its properties it is used for mostly columns frames , these would be made of entirely of steel; this is good as steel is very strong but when a load is but on steel from both ends such as a column the column could compress and buckling effect could happen, also if the load is great enough column could break (snap) .