Instrumentation Control: Resistance Temperature Detectors

Instrumentation Control: Resistance Temperature Detectors Abstract Within manufacturing, process control is fundamental in order to routinely produce high quality parts. Process control is an engineering discipline which can be defined as maintaining the output of a specific process within a desired range. [1] Temperature regulation is omnipresent in the world we live, for example, every living creature has autonomous bodily functions to regulate temperature. Artificially, central heating systems work in the same way, the user sets the desired temperature and the system detects the current state and makes adjustments to the temperature. A resistance temperature detector (hereby referred to as an RTD) is a temperature sensor which exploits the basic principles of science to play a key role in process control. 1. Literature Review An RTD is a temperature sensor which contains a resistive element. As the elements temperature changes so does its value of electrical resistance. It is this predictable property which enables us to control the temperature of a chosen substance or environment. RTDs are well known for their accuracy, stability and repeatability. The electrical resistance related to the variation of temperature is given as the Callendar-Van Dusen equation: Within a basic RTD the change in resistance of the element is small in comparison to the change in temperature. Therefore a bridge circuit is used to allow the measuring of the voltage drop across the resistor when applying a small constant current. Once the sensing element (see figure 1, below) has been placed where the temperature needs to be monitored or controlled, it will reach thermal equilibrium with its environment. At that temperature, the element will exhibit a certain value of resistance, this resistance is calculated and converted into a temperature which is fed back to the end user. Any change to the temperature of the environment will be represented by the change in electrical resistance of the RTD. There are five different construction variants of RTD elements, these include: Carbon resistor elements- these elements are cheap and popular. At low temperatures these elements are at their most reliable and are highly reproducible. Another advantage is that carbon resistor elements often dont suffer from hysteresis. Strain free elements- used in SPRTs (the highest accuracy of all RTDs) and can work up to 961.78 °C. These elements consist of a wire coil surrounded by inert gas. Thin film elements- a very thin layer of resistive material is deposited onto a ceramic substratum and coated in epoxy. These elements are not as stable as wire-wound or coiled elements, and they are only effective over a small temperature range. However they are smaller and cheaper than the standard wire-wound elements. Wire-wound elements- have a greater accuracy over wider temperature ranges. They consist of a length of pure metal in the form of a wire, usually wrapped around a glass or ceramic core. The elements are usually very fragile, and therefore, need protecting with a sheath. The diameter of the coil minimises the strain on the element by compromising between mechanical stability and expansion of the material. Coiled elements- currently the technology of choice, replacing wire-wound elements. They consist of a stress free design which lets the coil expand and contract freely as the temperature changes. The housing is made from ceramic oxide and the coils are threaded through bores, which are packed with fine ceramic powder. These elements are effective up to 850 °C. The most common materials used as RTD elements are platinum, nickel, copper, balco and tungsten. Platinum is the most popular due to it being very repeatable and quite sensitive, balco and tungsten are very rarely used. Platinum, copper and nickel have temperature ranges of 650 °C, 300 °C and 120 °C respectively and exhibit strong linear properties over a wide range of temperature. (see figure 2, below). 2. PT100 Sensors The most common type of RTD used within industry is the PT100. This RTD has an element of pure platinum and has an electrical resistance of 100à ¢Ã¢â‚¬Å¾Ã‚ ¦ at 0 °C, hence the name PT100. The resistance of a typical PT100 RTD changes at 0.39à ¢Ã¢â‚¬Å¾Ã‚ ¦ per 1 °C. 2.1 Wiring Variations Two wire configuration: As the name suggests, this PT100 RTD uses two wires. However this configuration does include a possible source of error where the resistance of the connecting wires is added to the resistance of the sensor. Should a company or individual choose this configuration they can combat this source of error by mounting a temperature transmitter close to the element. This configuration is best used when high accuracy is not required. Three wire configuration: The three wire configuration is the most widely used minimises the effects of the lead resistances. The two leads to the sensor are on adjoining arms, in each arm there is a lead resistance which is cancelled out if the two lead resistances are accurately the same. Four wire configuration: The accuracy of the measurement of resistance is increased by using the four-wire configuration. Voltage drop in the measuring leads is eliminated using four-terminal sensing. 2.2 Properties of PT100 RTDs 2.2.1 Precision PT100 RTDs are extremely precise. A tolerance of  ±0.75 °C is applied up to 300 °C, for temperatures between 700 °C and 800 °C a tolerance of 1% is applied. 2.2.2 Stability A PT100 RTD has a long term stability of around  ±0.2% of the 0% value over a 1000 hour (one year span). This test was conducted in special ovens with air heated to 800 °C. This property is arguably the greatest property of an RTD. 2.2.3 Speed of Response Speed of response is measured by submerging the PT100 sensor in water or air moving at 1 m/s with a 63.2% step change (see figure x). Thermo-electra show that the response time for one of their PT100 sensors are as follows [5]: Resistance -element mineral insulated Resistance-element with protection tube and insert Diameter 3-6mm 9mm Insertion length 100-500mm 100-150mm Response time in water (s) 0.6-4 30 Response time in air (s) 26-55 140 3. References [1] B.R. Mehta, Y. Jaganmohan Reddy. (2014). Batch Automation Systems. In: B.R. Mehta, Y. Jaganmohan Reddy Industrial Process Automation Systems: Design and Implementation. -: Butterworth-Heinemann. 135. [2] Correge. (). Head- or cable type mineral insulated probes. Available: http://www.correge.fr/rtd-sensor-mineral-insulated.html. Last accessed 11th Dec 2016. [3] Various. (2016). Resistance Thermometer. Available: https://en.wikipedia.org/wiki/Resistance_thermometer. Last accessed 21/12/2016. [4] Acromag. (2011). CRITERIA FOR TEMPERATURE SENSOR SELECTION OF T/C AND RTD SENSOR TYPES . Available: https://www.acromag.com/sites/default/files/RTD_Temperature_Measurement_917A.pdf. Last accessed 21/12/2016. [5] Thermo-electra. (-). Sensor Response Times. Available: http://www.thermo-electra.com/en/producten/technische-informatie/response-times. Last accessed 21/12/2016. [6] electrical4u. (2012). Resistance Temperature Detector or RTD | Construction and Working Principle. Available: http://www.electrical4u.com/resistance-temperature-detector-or-rtd-construction-and-working-principle/. Last accessed 22/12/2016.

The Psychometric Test and the Employee Selection Process Essay examples

The Psychometric Test and the Employee Selection Process Most employers want the ‘perfect fit’ for any position vacant for recruitment. They always tend to want the best man suitable for the job, technically and interpersonally. The common ways of recruiting an employee is by application forms, curriculum vitae, and interviewing sessions. Most candidates are polite at interviews just to put across a good impression to the interviewer. Just interviewing someone is not enough to know if you have the right person for the job. Ability can be relatively easy to assess through interviewing and skills testing. Testing interpersonal skills is another issue. To reduce the risk of hiring the wrong person, the use of psychometric testing has been adopted by more and more organisations to increase the validity and reliability of the recruitment process. Psychometrics is the application of the objective, scientific measurement and mathematics to psychology. It refers top the testing of cognitive of mental functions and personality and the analysis of result. The psychometric test covers a lot of tests used to assess a characters strength or weakness providing accurate profiles of the suitability for a position. â€Å"Psychometric† means measurement of the mind. The Psychometric test is a way of assessing an individual’s ability or personality in a measured and structured way. Also, a psychometric test could be said to be any standardized procedure for measuring sensitivity or memory, or intelligence or aptitude as well as personality. Psychometric tests are one measure by which an employer can discriminate against individuals in the selection process. The tests are often presented in a multiple guess form, either paper or electronically based. There are two types of the psychometric test. They include: . Aptitude/Skills Test- This depends on the nature of the job that has been applied for. This type of test could be numerical or verbal reasoning, spatial awareness or diagrammatic reasoning. They are often time constrained. . Personal Questionnaire- this type of test is used to access the certain personal qualities required of the candidate. Psychometric testing does have real value to add to the selection process. However, it is not limited to the recruitment phase. Many organisations have seen the benefit of psychometri... ...ers for the questions. . As the assessment is not a 100% accurate, there may be little or no correlation between the candidate’s answers and the way he carries out the job. In conclusion, Psychometric test is versatile and can be used as an aid for personnel selection and recruitment, career guidance, career development, team building and personal development. Psychometric test is used by a vast number of large and small companies who appreciate its cost effectiveness when compared to the hard soft and human cost of selection errors. Psychometric tests, although a useful selection tool to implement, have many flaws and in order to be valid must be carried out in a strict and controlled manner in order for an organisation to make the right choice when seeking to recruit an individual into an organisational role. Research now shows that, in comparison with selection by normal interviewing techniques, the use of supporting psychometric testing can significantly improve the match between the individuals and the job. The growing use of psychometric testing in selection and assessment has to some extent outpaced the level of sophistication and knowledge.

Recall Bias in Research Design Essay -- Research Methodology

It is most likely every major text on epidemiology involved in retrospective research is influenced by recall bias. Scientists have identified recall bias to occur when accuracy of recall regarding prior exposure is different for cases versus control (RAPHAEL, 1987). The possibility for recall bias exists whenever historical self-report information is elicited from respondents (RAPHAEL, 1987). Therefore, the potential for the occurrence is likely to be greatest in case-control studies or cross-sectional studies with retrospective elements, as well as some cohort prospective and control randomized trial designs (Hassan, 2006). Since recall bias is an undesired element, intended to potentially distort the study, the initial design of research study needs to implement a proper strategy. In construction of the design, an abstract, methods and conclusion alone do not restrict recall bias. To limit the need for recall itself it would be more desirable to depend on scientific data, as is the most obvious choice. However, research does not provide us with this luxury. Thus, one method to restrict or rule out recall bias is the use of actual exposure status verified through unbiased records (RAPHAEL, 1987). Although this method is most limited as it depends on the unbiased records made available in studies. The initial formatting of questionnaires is another consideration to insure research accuracy and validity scale. A popular form is the Minnesota Multiphasic Personality Inventory used in studies eliciting self-report responses (RAPHAEL, 1987). The MMPI has demonstrated successful outcomes and limited recall bias with an analytical approach to cross sectional studies. As assertive measurements to evaluate recall bias are in place, ... ...his evaluated? The valuable status collected during the initial emergency room visit presents the most usable information to this study, making this study reportable. Alcohol and drug use remain globally problematic and therefore epidemiological scientists continue to report findings of research in hopes of communicating its findings and finally the overall focus of making a change for the better. . References; BORGES, g. L.-M. (2005). A CASE-CONTROL STUDY OF ALCOHOL AND SUBSTANCE USE DISORDERS AS RISK FACTORS FOR NON-FATAL INJURY. Oxford Journals , 257-262. Hassan, E. (2006). Recall Bias can be a Threat to Retrospective and Prospective Research Designs . . The Internet Journal of Epidemiologyâ„ ¢ ISSN: 1540-2614 . RAPHAEL, K. (1987). Recall Bias: A Proposal for Assessment and Control. International Journal of Epidemiology , 167-171.

No More Hiroshima and Slough Poem Comparision Essay

There can be no doubt that â€Å"Slough† and â€Å"No More Hiroshima’s† share a large collection of differences. However, they additionally have similarities. The poem â€Å"Slough† written by John Betjeman and is expressing his hatred for the place. This becomes apparent from the beginning when he ask for â€Å"friendly bombs, come fall on slough. † The satirical humour and juxtaposition of â€Å"friendly† and â€Å"bomb† are ironic and portray a dark image of the place, and this is continued throughout the poem with words such as â€Å"Death†, and â€Å"Hell†. Moreover, the imagery of the poem is ferocious and ghastly which greats a sense of negativity towards Slough. The poem â€Å"No More Hiroshima’s† by James Kirkup shares a similarity with Slough due to the aspect of war. No More Hiroshima’s is constructed around the reconstruction of the city Hiroshima’s after having nuclear bombs released on it. Furthermore, both poets are infuriated by the cities. No More Hiroshima’s begins with the tourist arriving at the station, â€Å"At the station exit, my bundle in hand† this already creates a sense of the poet coming off the train being confused at how busy the station is and how he was expecting to see huge inspirational memorials, however he was astonished and disappointed to see no memorials and compares it to any ordinary Japanese town. The poet in Slough wishes for slough to be obliterated as it says â€Å"come bombs, and blow to smithereens† whereas the No More Hiroshima’s poem doesn’t wish for the place to be wounded as the poet still sees Hiroshima as a precious place but it has just been used in the erroneous way due to commercialization of the demolished city. Consequently I believe this portrays a sense of negativity and is extremely idiosyncratic from the poet Betjeman and this continues throughout the whole poem. In the poem No More Hiroshima’s the poet doesn’t present any characters In a clear manner. Therefore he can talk about the place in a more general manner. Conversely in Slough the poet introduces characters as he feels he has to take his emotions out on the people not the city as it says for example â€Å" and get that man with double chin, who’ll always cheat and always win, who washes his repulsive skin In women’s tears,† the poet here is vehement that the people are additionally a cause for the failure of Slough whereas the in No More Hiroshima’s there isn’t blame on the people.

Narrative Reporting

Narrative reporting and introduction of OFR is an important development in corporate responsibility. The introduction of mandatory OFR made several companies race to meet with the requirements of the law. Subsequently, the OFR was made non mandatory again but awareness has been created. Every investor knows that he should look at the OFR of a company he seeks to invest in. If the OFR is missing it raises doubts about the credibility and the intentions of the company .In future even though the mandatory clause has been withdrawn, companies are likely to produce more comprehensive and informative OFR than ever before.Narrative reporting concentrates on presenting events and actions in certain order so that complications and problems are understood. Narrative reporting concentrates on the descriptions, events and facts that pertain to events, identifying the personnel who are involved and the manner in which the sequence of events took place. The OFR (Operating and financial review) is a report included in a company’s annual report and accounts that is published to meet the requirement of corporate governance that enumerates the operating activities and financial affairs of the company.In the UK the Operating and Financial Review was introduced with the purpose of increasing corporate responsibility. The purpose of this requirement was that social and environmental issues would be described in the OTR and this would provide a wider level of information to the shareholder. In addition, it was expected that the OTR would in a way compel companies to carry out external audit of these issues. Specifically it was intended that the OFR would provide better information to the investors on the likely performance of the companies during the financial year.The contents of the OFR should have an overview of the capital structure of the company and the financial characteristics of the company. In addition, the OFR was required to provide the main risks and uncertaintie s that faced the company. Further, the OFR was required to have descriptions of the brand strength, market strengths, company reputation and R&D, that is the resources that the company enjoyed in the market. Most importantly, the OFR required the companies to disclose the objectives and strategies of the company (Financial Reporting Council 2007).The OFR also required the companies to disclose its relationships with suppliers, customer and employees. In other words the company was required to disclose its relationship with the stakeholders of the company. The company was also required to comment on the reputation of the company, especially in relation to the society and the environment. Moreover, the company was required to comment on the impact the reputation would have on the future performance of the company (Yeldar. R. 2007).In the UK the OFR disclosures have been left to an extent to the directors of the company. Their views on the different points are critical in making the di sclosure useful to the company. Moreover, the government has focused on the OFR to fill the lacunae in reporting that traditional financial statements left in the annual reports (Morris. G, McKay. S & Oates. A, 2006). If the board is so inclined, then the OFR can simply be relegated to a public relations activity of the company.The point is that if companies choose not to include corporate responsibility issues in their OFR then there may be a need for a mandatory inclusion of corporate responsibility indicators in the OFR. Even though OFR is driving the companies to disclose corporate responsibility issues, the final decision to disclose remains with the companies (Gee. P, 2006). The OFRs are required to honestly disclose the performance, development and the position of the company to help the investor make better decisions. In addition, the OFRs are required to provide the salient factors and the important trend that affect the present financial performance and the future status o f the company. It is believed that not too many boards of directors will be eager to make an honest disclosure of these trends.To assess the current state of narrative reporting in the UK let us take a look at the review of narrative reporting published by the ASB on January 15, 2007. The report gives some areas of improvement that is the key performance indicators are missing in narrative reporting, the companies are not careful in their description of the principal risks and uncertainties and do not mention their approaches in mitigating these risks and uncertainties. What is most important is that forward looking information is not disclosed in the narrative reports.The review lauds the companies for reporting an increasing number of environmental, employee and social issues, the companies are giving good description of current developments and present performance and that the companies are providing more or less good descriptions of their current business, markets, strategic pla ns and objectives (Ploix. H, & Charkham. J 2005). The auditors are currently required to comment on whether the OFR is consistent with their knowledge of the Annual Report and accounts. However, it is often seen that currently the companies in their OFR often give spin over substance.The companies over emphasize their favorable performance and avoid mentioning their areas of weaknesses. It is expected that now the companies will be required to product a broader annual report and specify their non financial performance and plans for future. For example, Shell is the biggest emitter of greenhouse gases in the UK and has a share of 23% of all emissions from FTSE 100 companies but this is not mentioned in the OFR of the company. There are no specific plans either to reduce emissions. Similarly, BP and Scottish Power are responsible for 17% of the emissions but this is not clearly mentioned in their annual reports.The lacuna in the law is that the auditor is required to compare the OFR s tatements with the financial reports and accounts and check if the statements in the OFR are in agreement with financial reports and accounts. This does not require the auditor to mention the omissions that have been made from the OFR nor does the audit of the narrative statement require the board of directors to make statements that disclose the weaknesses of the company. It is clear that in case of Shell, BP and Scottish Power if their emission levels of greenhouse gases are mentioned and the weaknesses in their future plans of reducing these emissions are clearly delineated in their annual reports, then several ethical investors may decide to stay away from these companies (Cowan. N, 2006, p 137).The recent history of the OFR is that the OFR was first introduced in 1993 by the ASB. At that time it was not mandatory. The Companies Act 1985(Operating and Financial Review and Directors’ Report etc.) Regulations 2005 required quoted companies to prepare a compulsory OFR and ot her companies to include in their Directors’ Reports a business review. Small companies were exempt from the requirements of this regulation.The Accounting Standards Board issued an accompanying Reporting Standard that those companies that complied with the Reporting Standard 1 would be presumed to have met the OFR Regulations. In November, 2005 the Chancellor announced that the government wanted to do away with the need for quoted companies to prepare an OFR. In January 2006 the Repeal Regulation of 2005 came into force that did away with the need for quoted companies to make an OFR.The Reporting Standard 1 was converted into a Reporting Statement. This remains just as a guiding statement for companies that decided to produce an OFR (Vilers. C, 2006). In the next month that is February 2006 the government requested suggestions and comments on improving the narrative reporting requirements. In May 2006 the government publicized amendments to the Business Review legislation. F inally, in November 2006, The Companies Act was given the final assent. and the Business Review requirements are now given legal sanction.Gordon Brown’s decision to abandon the mandatory nature of the OFR has been supported by two arguments. First, the government claims it wants to reduce bureaucracy. Second, government feels that the new requirements for business review meet the EU requirements for narrative reporting. This is the official line of the government.. However, there are other reasons that are being given as the reason for the abolition of the compulsory clause. It is claimed that the abolition of the mandatory requirement is offered as an incentive to business to remain in the UK and to attract new businesses to the UK. It is a part of the race to make UK attractive to business investors.Several environmental organizations like Friends of Earth and NGOs have decided to file a law suit against the government to force it to see reason. They see the withdrawal of t he mandatory clause as signal to the business sector to continue with their environmentally baneful expansion plans. These organizations had been earlier clamoring for mandatory social and environmental reporting for businesses. From this perspective it seems that Gordon Brown’s decision is not a good one.There are other reasons given to support Gordon Brown’s decision. The claim is that more than 80% of the listed companies will voluntarily comply with the requirements of Reporting Statement and generate OFR statements. Those that do not will face investor reaction and comply with the Reporting Statement requirements. Those that persist in not producing an OFR voluntarily will be perceived as not transparent by the investing public. In addition, the proponents of the abolition of mandatory OFR aver that the size and the complexity of the annual reports daunting to most investors. In 2005 the average length of the annual reports was 71 pages. Adding to this only confus es the shareholders.Finally, the materiality get out clause has made the compulsory OFR ineffective. This has also allowed companies to get out of the need to report their weaknesses. However, we should not write off the OFR as dead. Every business knows that it should have an OFR to inform its shareholder. The need for qualitative, non-financial information has been created in the investors. If a company does not produce an OFR the investor may suspect it several faults. The end result will be that the shareholders will find it prudent to stay away from companies that do not produce a comprehensive OFR. There will be reputed persons who will stay away from the boards of companies that do not produce an OFR that meets the standard prescribed by the ASB.The OFR lives in the business review. The government is not compelling the companies to produce an OFR but the shareholders, investors and other stakeholders will compel the companies to produce and OFR. Environmental organizations an d NGOs will take up the matter with companies that do not report on social and environmental issues. Companies that refuse to make OFRs may be shunned by ethical investors, high profile employees and environmentally conscious business partners. The awareness has been created, guidelines have been drafted and the importance of corporate responsibility has been emblazoned. The OFR has taken on a life of its own and even without compulsion it will feature in the annual reports of most UK companies.As the consciousness of investors increases, as the top employees become choosier and as corporations become more environmentally sensitive, OFR will continue to thrive. There is no need to revive the mandatory clause. Enough consciousness has been created to make the corporate sector aware and alive to its reporting responsibilities, the Business Review is adequate for this purpose. Those companies that do not behave in a responsible manner will suffer because they will not be able to sustai n the interests of stakeholders that matter.To sum, there are a number of reasons given in support of the abolition of the mandatory clause and a number of reasons are being given for the reintroduction of mandatory requirements for OFR However, the importance of the OFA has been driven home to the companies, the investors and other stakeholders. Financial reporting alone does not give enough information to make a decision and he knows that an OFA is important. The OFA continues to live in the UK corporate world even after the mandatory clause has been abolished.References:Cowan. N, 2006 Risk Analysis and Evaluation, Lessons Professional Publishing..Financial Reporting Council 2007 ‘ASB Publishes Review of Narrative Reporting’. Retrieved on January 30, 2007 from http://www.frc.org.uk-Gee. P, 2006 UK GAAP for Business and Practice, ElsevierMorris. G, McKay. S & Oates. A, 2006 Finance Director’s Handbook, Elsevier.Ploix. H, & Charkham. J 2005 Keeping Better Company : Corporate Governance Ten Years on, Oxford University Press.Vilers. C, 2006, Corporate Reporting and Company Law, Cambridge University Press. 205 -209Yeldar. R. 2007 Accounting Standards Board Publishes Review of Narrative Reporting, Retrieved on January 30, 2007 from: http://ry.com/news/news/?id=3345

Ccot Rome 100-600 C.E. Essay

Between 100 and 600 C.E., Rome underwent significant cultural and political changes. Culturally, the empires religious beliefs had changed, resulting in the predominance of Christianity. Politically, Rome’s economy divided. As for continuities, paterfamilias and women’s right remained the same throughout the time period. Religion was a large part of the roman culture, and made a major change to Christianity. When Rome was still n early empire, Paganism, where there was a belief in multiple gods, was the main religion. Initially the poor were the first to switch to Christianity, which later spread to the higher classes of society. The religion was rejected in 100 C.E., but Constantine legalized it in 313 C.E. The Roman Empire was quickly enveloped by Christianity and took over the other religions. A major political change was the division of the once united Roman Empire into the Byzantium to the East, and Rome remaining in the West. Rome was so massive that under one ruler, it was impossible to make everyone happy, which led to dividing the empire. Because of economic and leadership issues, Germanic tribes tried to take over the land to the east and west. Rome had to split its force to fight them, ultimately adding to the chaos that divided the empire. Women’s right had remained constant throughout the time period. Unlike in China and India women, mainly of the upper class, would have a larger participation in business and work. Woman were able to attend schooling together or similar to men at public schools, and attended religious and social events. Paterfamilias was another continuity in 100 to 600 C.E. Rome. The male father had complete control over his family, and his children’s full lives. This included occupations, spouses, possessions, he could even legally kill them.

The Vampire Diaries: The Fury Chapter Two

Stefan's voice was quietly savage. â€Å"That's what you wanted, wasn't it, Damon? And now you've got it. You had to make her like us, like you. It wasn't enough just to kill her.† Damon didn't glance back at him. He was looking at Elena intently through those hooded eyes, still kneeling there holding her chin. â€Å"That's the third time you've said that, and I'm getting a little tired of it,† he commented softly. Disheveled, still slightly out of breath, he was yet self-composed, in control. â€Å"Elena, did I kill you?† â€Å"Of course not,† Elena said, winding her fingers in those of his free hand. She was getting impatient. What were they talking about anyway? Nobody had been killed. â€Å"I never thought you were a liar,† Stefan said to Damon, the bitterness in his voice unchanged. â€Å"Just about everything else, but not that. I've never heard you try to cover up for yourself before.† â€Å"In another minute,† said Damon, â€Å"I'm going to lose my temper.† What more can you possibly do to me? Stefan returned. Killing me would be a mercy. â€Å"I ran out of mercy for you a century ago,† Damon said aloud. He let go, finally, of Elena's chin. â€Å"What do you remember about today?† he asked her. Elena spoke tiredly, like a child reciting a hated lesson. â€Å"Today was the Founders' Day celebration.† Flexing her fingers in his, she looked up at Damon. That was as far as she could get on her own, but it wasn't enough. Nettled, she tried to remember something else. â€Å"There was someone in the cafeteria†¦ Caroline.† She offered the name to him, pleased. â€Å"She was going to read my diary in front of everyone, and that was bad because†¦Ã¢â‚¬  Elena fumbled with the memory and lost it. â€Å"I don't remember why. But we tricked her.† She smiled at him warmly, conspiratorially. â€Å"Oh, ‘we' did, did we?† â€Å"Yes. You got it away from her. You did it for me.† The fingers of her free hand crept under his jacket, searching for the square-cornered hardness of the little book. â€Å"Because you love me,† she said, finding it and scratching at it lightly. â€Å"You do love me, don't you?† There was a faint sound from the center of the clearing. Elena looked and saw that Stefan had turned his face away. â€Å"Elena. What happened next?† Damon's voice called her back. â€Å"Next? Next Aunt Judith started arguing with me.† Elena pondered this a moment and at last shrugged. â€Å"Over†¦ something. I got angry. She's not my mother. She can't tell me what to do.† Damon's voice was dry. â€Å"I don't think that's going to be a problem anymore. What next?† Damon's voice was dry. â€Å"I don't think that's going to be a problem anymore. What next?† â€Å"And where did you go in Matt's car?† â€Å"To Wickery Bridge,† Stefan said, turning back toward them. His eyes were desolate. â€Å"No, to the boardinghouse,† Elena corrected, irritated. â€Å"To wait for†¦ mm†¦ I forget. Anyway, I waited there. Then†¦ then the storm started. Wind, rain, all that. I didn't like it. I got in the car. But something came after me.† â€Å"Someone came after you,† said Stefan, looking at Damon. â€Å"Some thing,† Elena insisted. She had had enough of his interruptions. â€Å"Let's go away somewhere, just us,† she said to Damon, kneeling up so that her face was close to his. â€Å"In a minute,† he said. â€Å"What kind of thing came after you?† She settled back, exasperated. â€Å"I don't know what kind of thing! It was like nothing I've ever seen. Not like you and Stefan. It was†¦Ã¢â‚¬  Images rippled through her mind. Mist flowing along the ground. The wind shrieking. A shape, white, enormous, looking as if it were made out of mist itself. Gaining on her like a wind-driven cloud. â€Å"Maybe it was just part of the storm,† she said. â€Å"But I thought it wanted to hurt me. I got away though.† Fiddling with the zipper to Damon's leather jacket, she smiled secretly and looked up at him through her lashes. For the first time, Damon's face showed emotion. His lips twisted in a grimace. â€Å"You got away.† â€Å"Yes. I remembered what†¦ someone†¦ told me about running water. Evil things can't cross it. So I drove toward Drowning Creek, toward the bridge. And then†¦Ã¢â‚¬  She hesitated, frowning, trying to find a solid memory in the new confusion. Water. She remembered water. And someone screaming. But nothing else. â€Å"And then I crossed it,† she concluded finally, brightly. â€Å"I must have, because here I am. And that's all. Can we go now?† Damon didn't answer her. â€Å"The car's still in the river,† said Stefan. He and Damon were looking at each other like two adults having a discussion over the head of an uncomprehending child, their hostilities suspended for the moment. Elena felt a surge of annoyance. She opened her mouth, but Stefan was continuing. â€Å"Bonnie and Meredith and I found it. I went underwater and got her, but by then†¦Ã¢â‚¬  By then, what? Elena frowned. Damon's lips were curved mockingly. â€Å"And you gave up on her? You, of all people, should have suspected what might happen. Or was the idea so repugnant to you that you couldn't even consider it? Would you rather she were really dead?† people, should have suspected what might happen. Or was the idea so repugnant to you that you couldn't even consider it? Would you rather she were really dead?† Elena opened her mouth again, but Damon laid two fingers on it to keep her quiet. He said smoothly, â€Å"And that's the problem now-or are you too blind to see that, too? You told me to look at her; look at her yourself. She's in shock, irrational. Oh, yes, even I admit that.† He paused for a blinding smile before going on. â€Å"It's more than just the normal confusion after changing. She'll need blood, human blood, or her body won't have the strength to finish the change. She'll die.† What do you mean irrational? Elena thought indignantly. â€Å"I'm fine,† she said around Damon's fingers. â€Å"I'm tired, that's all. I was going to sleep when I heard you two fighting, and I came to help you. And then you wouldn't even let me kill him,† she finished, disgusted. â€Å"Yes, why didn't you?† said Stefan. He was staring at Damon as if he could bore holes through him with his eyes. Any trace of cooperation on his part was gone. â€Å"It would have been the easiest thing to do.† Damon stared back at him, suddenly furious, his own animosity flooding up to meet Stefan's. He was breathing quickly and lightly. â€Å"Maybe I don't like things easy,† he hissed. Then he seemed to regain control of himself once more. His lips curled in mockery, and he added, â€Å"Put it this way, dear brother: if anyone's going to have the satisfaction of killing you, it will be me. No one else. I plan to take care of the job personally. And it's something I'm very good at; I promise you.† â€Å"You've shown us that,† Stefan said quietly, as if each word sickened him. â€Å"But this one,† Damon said, turning to Elena with glittering eyes, â€Å"I didn't kill. Why should I? I could have changed her any time I liked.† â€Å"Maybe because she had just gotten engaged to marry someone else.† Damon lifted Elena's hand, still twined with his. On the third finger a gold ring glittered, set with one deep blue stone. Elena frowned at it, vaguely remembering having seen it before. Then she shrugged and leaned against Damon wearily. â€Å"Well, now,† Damon said, looking down at her, â€Å"that doesn't seem to be much of a problem, does it? I think she may have been glad to forget you.† He looked up at Stefan with an unpleasant smile. â€Å"But we'll find out once she's herself again. We can ask her then which of us she chooses. Agreed?† Stefan shook his head. â€Å"How can you even suggest that? After what happened†¦Ã¢â‚¬  His voice trailed off. â€Å"With Katherine? I can say it, if you can't. Katherine made a foolish choice, and she paid the price for it. Elena is different; she knows her own mind. But it doesn't matter if you agree,† he added, overriding Stefan's new protests. â€Å"The fact is that she's weak now, and she needs blood. I'm going to see that she gets it, and then I'm going to find who did this to her. You can come or not. Suit yourself.† He stood, drawing Elena up with him. Let's go. She recognized the place where they left the wood. She had been there earlier today. Now, however, there was some sort of frenzied activity going on: red and blue lights flashing on cars, spotlights framing the dark huddled shapes of people. Elena looked at them curiously. Several were familiar. That woman, for instance, with the thin harrowed face and the anxious eyes-Aunt Judith? And the tall man beside her-Aunt Judith's fianc.., Robert? There should be someone else with them, Elena thought. A child with hair as pale as Elena's own. But try as she might, she could not conjure up a name. The two girls with their arms around each other, standing in a circle of officials, those two she remembered though. The little red-haired one who was crying was Bonnie. The taller one with the sweep of dark hair, Meredith. â€Å"But she's not in the water,† Bonnie was saying to a man in a uniform. Her voice trembled on the edge of hysteria. â€Å"We saw Stefan get her out. I've told you and told you.† â€Å"And you left him here with her?† â€Å"We had to. The storm was getting worse, and there was something coming-† â€Å"Never mind that,† Meredith broke in. She sounded only slightly calmer than Bonnie. â€Å"Stefan said that if he-had to leave her, he'd leave her lying under the willow trees.† â€Å"And just where is Stefan now?† another uniformed man asked. â€Å"We don't know. We went back to get help. He probably followed us. But as for what happened to-to Elena†¦Ã¢â‚¬  Bonnie turned back and buried her face in Meredith's shoulder. They're upset about me, Elena realized. How silly of them. I can clear that up, anyway. She started forward into the light, but Damon pulled her back. She looked at him, wounded. â€Å"Not like that. Pick the ones you want, and we'll draw them out,† he said. â€Å"Want for what?† â€Å"For feeding, Elena. You're a hunter now. Those are your prey.† Elena pushed her tongue against a canine tooth doubtfully. Nothing out there looked like food to her. Still, because Damon said so, she was inclined to give him the benefit of the doubt. â€Å"Whichever you think,† she said obligingly. Damon tilted his head back, eyes narrowed, scanning the scene like an expert evaluating a famous painting. â€Å"Well, how about a couple of nice paramedics?† Damon tilted his head back, eyes narrowed, scanning the scene like an expert evaluating a famous painting. â€Å"Well, how about a couple of nice paramedics?† Damon barely glanced over his shoulder at Stefan. â€Å"Why not?† â€Å"Because there've been enough attacks. She may need human blood, but she doesn't have to hunt for it.† Stefan's face was shut and hostile, but there was an air of grim determination about him. â€Å"There's another way?† Damon asked ironically. â€Å"You know there is. Find someone who's willing-or who can be influenced to be willing. Someone who would do it for Elena and who is strong enough to deal with this, mentally.† â€Å"And I suppose you know where we can find such a paragon of virtue?† â€Å"Bring her to the school. I'll meet you there,† Stefan said, and disappeared. They left the activity still bustling, lights flashing, people milling. As they went, Elena noticed a strange thing. In the middle of the river, illuminated by the spotlights, was an automobile. It was completely submerged except for the front fender, which stuck out of the water. What a stupid place to park a car, she thought, and followed Damon back into the woods. Stefan was beginning to feel again. It hurt. He'd thought he was through with hurting, through with feeling anything. When he'd pulled Elena's lifeless body out of the dark water, he'd thought that nothing could ever hurt again because nothing could match that moment. He'd been wrong. He stopped and stood with his good hand braced against a tree, head down, breathing deeply. When the red mists cleared and he could see again, he went on, but the burning ache in his chest continued undiminished. Stop thinking about her, he told himself, knowing that it was useless. But she wasn't truly dead. Didn't that count for something? He'd thought he would never hear her voice again, never feel her touch†¦ And now, when she touched him, she wanted to kill him. He stopped again, doubling over, afraid he was going to be sick. Seeing her like this was worse torture than seeing her lying cold and dead. Maybe that was why Damon had let him live. Maybe this was Damon's revenge. And maybe Stefan should just do what he'd planned to do after killing Damon. Wait until dawn and take off the silver ring that protected him from sunlight. Stand bathing in the fiery embrace of those rays until they burned the flesh from his bones and stopped the pain once and for all. Stefan detoured toward the boardinghouse. He needed to clean up before he could let humans see him. In his room, he washed the blood from his face and neck and examined his arm. The healing process had already begun, and with concentration he could accelerate it still further. He was burning up his Powers fast; the fight with his brother had already weakened him. But this was important. Not because of the pain-he scarcely noticed that-but because he needed to be fit. Damon and Elena were waiting outside the school. He could feel his brother's impatience and Elena's wild new presence there in the dark. â€Å"This had better work,† Damon said. Stefan said nothing. The school auditorium was another center of commotion. People ought to have been enjoying the Founders' Day dance; in fact, those who had remained through the storm were pacing around or gathered in small groups talking. Stefan looked in the open door, searching with his mind for one particular presence. He found it. A blond head was bent over a table in the corner. Matt. Matt straightened and looked around, puzzled. Stefan willed him to come outside. You need some fresh air, he thought, insinuating the suggestion into Matt's subconscious. You feel like just stepping out for a moment. To Damon, standing invisible just beyond the light, he said, Take her into the school, to the photography room. She knows where it is. Don't show yourselves until I say. Then he backed away and waited for Matt to appear. Matt came out, his drawn face turned up to the moonless sky. He started violently when Stefan spoke to him. â€Å"Stefan! You're here!† Desperation, hope, and horror struggled for dominance on his face. He hurried over to Stefan. â€Å"Did they-bring her back yet? Is there any news?† â€Å"What have you heard?† Matt stared at him a moment before answering. â€Å"Bonnie and Meredith came in saying that Elena had gone off of Wickery Bridge in my car. They said that she†¦Ã¢â‚¬  He paused and swallowed. â€Å"Stefan, it's not true, is it?† His eyes were pleading. Stefan looked away. â€Å"Oh, God,† Matt said hoarsely. He turned his back on Stefan, pressing the heels of his hands into his eyes. â€Å"I don't believe it; I don't. It can't be true.† â€Å"Matt†¦Ã¢â‚¬  He touched the other boy's shoulder. â€Å"I'm sorry.† Matt's voice was rough and ragged. â€Å"You must be going through hell, and here I am making it worse.† His only other option was to tell Matt the truth. Let Matt make his own choice, knowing everything. â€Å"If there were something you could do for Elena right now,† he said, â€Å"would you do it?† Matt was too lost in emotion to ask what kind of idiotic question that was. â€Å"Anything,† he said almost angrily, rubbing a sleeve over his eyes. â€Å"I'd do anything for her.† He looked at Stefan with something like defiance, his breathing shaky. Congratulations', Stefan thought, feeling the sudden yawning pit in his stomach. You've just won yourself a trip to the Twilight Zone. â€Å"Come with me,† he said. â€Å"I've got something to show you.†