Ordinary electrical cables suffice to carry low frequency alternating current (AC), such as mains power, which reverses direction 100 to 120 times per second, and audio signals. However, they cannot be used to carry currents in the radio frequency range,[1] above about 30 kHz, because the energy tends to radiate off the cable as radio waves, causing power losses. Radio frequency currents also tend to reflect from discontinuities in the cable such as connectors and joints, and travel back down the cable toward the source.[1][2] These reflections act as bottlenecks, preventing the signal power from reaching the destination. Transmission lines use specialized construction, and impedance matching, to carry electromagnetic signals with minimal reflections and power losses. The distinguishing feature of most transmission lines is that they have uniform cross sectional dimensions along their length, giving them a uniform impedance, called the characteristic impedance,[2][3][4] to prevent reflections. Types of transmission line include parallel line (ladder line, twisted pair), coaxial cable, and planar transmission lines such as stripline and microstrip.[5][6] The higher the frequency of electromagnetic waves moving through a given cable or medium, the shorter the wavelength of the waves. Transmission lines become necessary when the transmitted frequency’s wavelength is sufficiently short that the length of the cable becomes a significant part of a wavelength. At microwave frequencies and above, power losses in transmission lines become excessive, and waveguides are used instead,[1] which function as “pipes” to confine and guide the electromagnetic waves.[6] Some sources define waveguides as a type of transmission line;[6] however, this article will not include them. At even higher frequencies, in the terahertz, infrared and visible ranges, waveguides in turn become lossy, and optical methods, (such as lenses and mirrors), are used to guide electromagnetic waves.[6] The theory of sound wave propagation is very similar mathematically to that of electromagnetic waves, so techniques from transmission line theory are also used to build structures to conduct acoustic waves; and these are called acoustic transmission lines.

Constructing your dream house has been a nightmare in Pakistan. A house which everyone dreams of, majority can turn the dream into a reality only once in their lifetime. A dream turns into a nightmare when one gets into the hands of unskilled and non-technical labor resulting in form of financial loss and above all mental stress. Nobody else is to be blamed in this situation, rather the one him/herself, whose lack of knowledge and fine research brings him/her to this stage. As its said “Its never too late”, indeed it is! But to revert the mistakes and wrong doings, extra cost will have to be sustained hence causing the financial loss. Moreover extra time will be spent resulting in time-loss too. Team Overc’s is bringing a series of construction guides to educate viewers about the process of constructing dream house in Pakistan In a market like Pakistan, 80% of construction industry is in the grip of un-professional and non-technical contractors. General public also prefers this contractor system due to budget constraints and cost savings. In this system the construction of house starts without defining any roadmap and the owner or client is provided with literally no idea about approximate end cost. Secondly workmanship plays an important role in construction of house, workmanship comes with teamwork. In contractor system there is no team available to supervise the project at any stage, hence all the burden of supervision rests on the shoulders of client or owner himself. Lets have a brief look at other factors that make house construction a nightmare: Insufficiency of fine research before starting the proceedings Starting the work without making a proper roadmap. Compromising on quality of material for saving the costs Compromising on quality of labor and contractors for saving the costs Lack of self supervision Unprofessional teamwork and workmanship Inappropriate behaviors with labor and contractors Financial constraints Improper paper work and agreements Lack of technical knowledge Artical from Website.

Pakistan has some of the highest values of insolation in the world,[citation needed] with eight to nine hours of sunshine per day, ideal climatic conditions for solar power generation. However, the country has been slow to adopt the technology. The country has solar plants in Pakistani Kashmir, Punjab, Sindh and Balochistan. Initiatives are under development by the International Renewable Energy Agency, the Japan International Cooperation Agency, Chinese companies, and Pakistani private sector energy companies. The country aims to build the world’s largest solar power park, the Quaid-e-Azam Solar Power Park (QASP) in the Cholistan Desert, Punjab, by 2017 with a 1 GW capacity. A plant of this size would be enough to power around 320,000 homes