An integrated control on thermal and noise environment of tropical building material

The environmental problems of thermal and noise environment are recently considered the most important contributors to the tropical building in an urban area. The porous tropical materials provide both a solution for cooling and airborne noise problem from the source to receiver when the wind is in the same direction. This research optimizes the integrated control of thermal and noise environment which are directed into building material evaluation. Surabaya is selected as representative of the hotter area of the lowland while Malang is determined as the colder urban area of the highland. An eco-tropical lightweight material, wood, is examined as a case study. The field measurement for surface material temperature and its transmission loss were conducted in order to give information on thermal and acoustical properties of the material. The optimization is conducted by comparing Sound Reduction Index and by Conduction Heat Flow. The results highlighted that for the same material, the thickness that effect on its mass is important for both thermal and noise control. The higher the thickness is, the higher the Sound Reduction Index and the lower the conduction heat flow are. Modifying material by adding the thickness of wood results that by material mass minimum 36.5 kg/m2, the critical lowland building meets the standard of World Health Organization noise limits and has lower heat gain.

Analysis of Thermal Stresses in a Layered Circuit Board

When choosing materials for a printed circuit board (PCB), it appears that a common misconception is that the coefficients of thermal expansion should be matched as closely as possible to minimize the stresses. In this paper it is shown that this is not necessarily true. A one-dimensional thermal stress analysis is considered for a printed circuit board (PCB) with N layers. Bending is neglected and average axial normal stresses and shear stresses are accounted for. It is shown that the solution for the shear stresses between layers can be written in the form of a difference equation (recurrence relation). For the first example, a two-layer board is considered. The solution leads to a design guideline. If there is a shear stress design limit then based on this a plot can be made to choose the optimum ratio of CTEs for the layers depending upon whether the conduction heat flow q is zero or not and depending upon magnitude of temperature change.. If q = 0, then matching the coefficients of expansion α1 and α2 reduces the stress to zero. However if q is not zero at some times, then a choice of the CTE ratio α1/α2 should be made to keep the stress between the design limits. For three or more layers with different properties a design optimization scheme can be used to choose values of the coefficients of thermal expansion.

Positive test of the paleomagnetic method for estimating burial depth using a dike contact

Detailed magnetic measurements were made on specimens from profiles across the contact zones of two unmetamorphosed Miocene diabase dikes. The dikes cut Cretaceous plutonic rocks of the Coast Crystalline Complex near Bella Bella, British Columbia. The dikes feed flat-lying basalts that outcrop nearby. This indicates post-Miocene uplift is less than 1 km in the area. Alternating field demagnetization, magnetic susceptibility, thermal demagnetization, and magnetic force balance measurements were made on the specimens. From them, the distance from the contact and the maximum reheated temperature of the magnetic hybrid zone were determined. Results are reported for the Thorburne Island contact only because the other contact had unsuitable remanence characteristics. Using standard conduction heat flow equations the ambient temperature of the host rock at the time of intrusion was found to be 18 ± 5 °C giving a determined depth for the present erosion surface at the time of intrusion of 0.3 ± 0.1 km. This is the first positive test of the magnetic paleogeobarometric method.