Thermosyphons :: physics

Tasked with the quest to economically and efficiently extend civilization into the Northern regions, the construction industry has been hindered by the presence of perennially frozen ground. The thermosyphon is a device that facilitates the harmonious union of structure and ice. This paper will serve as a tutorial on thermosyphons, and present an exploration into the physical concepts that allow their operation. The physical concepts and phenomenon that enable the operation of thermosyphons can at times be complex-but don’t be scared. This tutorial will start with the most rudimentary explanation of thermosyphons, and proceed from there to deliver more in depth examinations in a step by step process. Let’s get right down to business. The steps in thermosyphon operation are: STEP 1-Heat flows into the thermosyphon, STEP 2-Heat flows through the thermosyphon tube, and STEP 3-Heat is released into the atmosphere. Simply stated, a thermosyphon is a device which moves heat from one place to another. There are different types of thermosyphons which are used for different applications, but for the purposes of this primer we will concentrate on thermosyphons used by the construction industry to stabilize frozen ground. For example, consider a road built over permafrost.. In this situation it is desirable to keep the ground from thawing, otherwise the road embankment will be destroyed. A thermosyphon â€Å"collects heat† from the frozen ground. This collected heat is brought to the top of the thermosyphon and the cooling fins, where it is released into the atmosphere. In this way, the ground remains frozen. Now, the thought of frozen soil warming the atmosphere may be hard to grasp. This brings us to an important point about the thermosyphon- they only work when the ambient air temperature is below the temperature of the soil (less than 31 degrees Farenheight). With this in mind, we can consider thermosyphons from a different perspective; a thermosyphon increases the exposure of sub-surface soil to freezing temperatures. Another thought, although not totally correct from a physical standpoint, is that the thermosyphon brings cold into the soil. Let’s examine the thermodynamic process by which a thermosyphon operates. This process is outlined below in a step by step chronology. Step 1-There is an accumulation of the working fluid in the bottom of the thermosyphon. The most important factor that governs the choice of a working fluid is that it must have an extremely low boiling point. Permafrost soil is typically at a temperature of 31F and consequently the fluid boiling point should be less than 31F.

Jeronimo Martins Group’s Consolidated Balance Sheet Essay

Jeronimo Martins Group’s Consolidated Balance Sheet as of 31 December 2011 and 31 December 2010, has been analyzed respectively the correspondents values, structure and relevant changes for assets and Liabilities & Shareholder’s Equity with following conclusions: I.The main assets of Jeronimo Martins Group are noncurrent (about 75%) concentrated mostly in tangible assets (about 50%) followed for the intangible assets (about 18%); II.The current assets are mostly inventories and cash or cash equivalent; III.The main liabilities of Jeronimo Martins Group are current (about 55%) concentrated mostly in trade creditors, accrued costs and deferred income; IV.The noncurrent liabilities are mostly Borrowings; V.Total Shareholders’ Equity represent around 30% of Total Shareholders’ Equity and Liabilities; VI.The biggest changes in assets, 2010 to 2011, are referred to derivative financial Instruments (-78%) and Cash and Cash equivalents (74%); VII.Changes, 2010 to 2011, in current assets are 27,1% and noncurrent are 2,4%; VIII.The biggest changes in liabilities and total equity are referred to retained earnings (250%) and fair value and other reserves (-101%), provisions for risk and contingences (106%); IX.Changes, in 2010 to 2011, in current liabilities are 11% and noncurrent are -27% and total equity are 32,63%; The structure, values and changes listed above means that Jeronimo Martins Group had, in 2010 and 2011, mostly of its assets as noncurrent, which aren’t expect to be converted into cash or consumed within 12 month. The current ratio is below 1, so this company doesn’t have a big liquidity. Analyzed the 10 biggest companies in the food area, the current ratio is below those values observed such as in Dole food company (current ratio is 1,5). The current ratio is an entity ability to meet its current obligations or to maturing short term obligations, is an important measure of its financial health. This company present 0,406 (2010) and 0,464 (2011) current ratios, more current liabilities than current assets. The total debt to equity ratio represents the long term viability of the company, measure the degree of the indebtedness relative to its equity funding. This company present 2 (2010 and 2011) total debt to equity ratio, more total debt than equity, this imply that greater is this ratio greater is strain on the company to make regular payments to debts holders and higher is the risk of bankruptcy.

The Benefits of Attending an All-Girls School

Not every student can excel in a coeducational classroom, and thats why many students opt for single-sex schools. When it comes to girls, in particular, these important developmental years can be greatly enhanced by attending the right school. So, what are the benefits of attending a girls school? Why should your daughter attend a girls school instead of a coed school? Girls Schools Empower Students to Excel Many girls cannot achieve their full potential in a coeducational school. With the impact of peer pressure and the perceived need to conform to popular opinion and thinking, including the desire to be accepted, can all impact girls. These are just some of the reasons which make many girls suppress their own personalities and individuality in a coed academic setting. Left to their own devices in a single-sex environment, girls are often  more likely to take on challenging math and science subjects and engage wholeheartedly in serious sports - all things girls arent supposed to like. Competition is a Good Thing Girls will ignore gender stereotypes and develop their competitive side more fully in a single-sex academic setting. There are no boys to impress, no boys to compete for between other girls. They dont have to worry about being called tomboys. Their peers understand whats happening. Everybody feels comfortable being themselves. Laying Foundations for Leadership Women have made significant advances in the leadership arena. Hilary Clinton ran for the office of President of the United States. Clinton, Madeleine Albright, and Condoleezza Rice have been Secretary of State. Golda Meir was Premier of Israel. Margaret Thatcher was Prime Minister of England and so on. Carleton Fiorina was CEO of Hewlett-Packard. These excellent achievements notwithstanding, women still find it difficult rising to senior positions in any endeavor. Why? Because girls lack inspiring role models and appealing presentation of critical subjects like math, technology and science which give men the competitive edge in their career paths. Skilled teachers who understand girls and the way they learn can kindle a girls interest in non-traditional subjects. They can encourage a young lady to dream outside of the box and want a career as a captain of industry as opposed to just being a teacher or a nurse. Girls at Single-Sex  Schools are More Likely to Excel at Athletics Its true, and theres  research  to support this finding. Middle school girls are more likely to engage in competitive athletics than their peers at  coed  schools. A single-sex environment often feels empowering to students, especially girls, and encourages them to try new things. When boys arent around, girls are more likely to take a risk and try something new.   Girls Schools are Inspirational Learning and Living Environments Until youve actually spent time at an all-girls school, its hard to fully appreciate the environment of encouragement and inspiration that is created. When a school is limited to only educating girls, the pedagogy changes, and the science behind how a female brain works and how girls grow and mature all become part of the core educational paths set forth for students. Students report feeling more free to speak and express themselves, which leads to a stronger development of a love of learning.   Girls Schools may Offer More Opportunities to Succeed According to the National Coalition of Girls Schools, nearly 80% of girls school students report feeling challenged to the point of achieving their full potential, and more than 80% of graduates from all-girls schools report that they consider their academic performance as highly successful. Students enrolled in these single-sex environments also report having more confidence than their peers at coeducational institutions. Some even report that their college professors can spot an all-girls school graduate. An all-girls school can help your daughter be all she can be simply by encouraging and nurturing her. Everything is possible. Nothing is off limits. Resources Find Girls Schools here.The National Association For Single Sex Public Education enriches the debate with some compelling research.The Bromley Brook School for Girls makes a great case in its Philosophy article. Article edited by  Stacy Jagodowski