Dhansak consumed for three days after the death of a near one. And dhansak is used to break this abstinence on the fourth day. Hence, dhansak is never prepared on auspicious occasions like festivals and weddings. Dhansak is made by cooking mutton cubes with a mixture of various lentils and vegetables. Traditionally, four lentils (arhar dal, Bengal gram or chana dal, red masoor dal and brown masoor dal) are used, but one or more of the lentils may be omitted or substituted. The vegetables include potato, tomato, brinjal, pumpkin and fenugreek leaves: again, substitutions, such as squash for pumpkin, and sweet
Pulse tube refrigerator developed for cooling of astronomical detectors where liquid cryogens are typically used, such as the Atacama Cosmology Telescope or the Qubic experiment (an interferometer for cosmology studies). PTRs are used as precoolers of dilution refrigerators. Pulse tubes will be particularly useful in space-based telescopes such as the James Webb Space Telescope where it is not possible to replenish the cryogens as they are depleted. It has also been suggested that pulse tubes could be used to liquefy oxygen on Mars. Here the so-called Stirling-type single-orifice pulse-tube refrigerator will be treated operating with an ideal gas (helium) as the working fluid.