Unit Total Area Research Articles

Secondary Spaces of Entrance, Corridor, and Balcony in Tehran Housing - A Comparative Analysis with Nagoya Residences

Due to increasing costs and shrinkage of Tehran housing, interior layout plays a more critical role. In addition to the main spaces, such as the bathroom, kitchen, and bedroom, which are present and vital in each residential unit, we identified entrance, corridor, and balcony in our Tehran samples as secondary spaces. We aimed to investigate these spaces' role in Tehran's current housing; we analyzed their existence, size, and relationship with the unit's total area by considering the background and history of these spaces. Japan's experience in small housing convinced us to utilize under 100 m2 of Nagoya samples for comparison. Results revealed sufficient area for these three spaces in all Nagoya samples. In contrast, these spaces in a large percentage of Tehran samples did not exist or lacked efficiency contrary to related rules and regulations. There was a weak correlation between unit size and the lack of entrance and balcony, but corridor was usually removed in smaller units. We suggest separate entrance and corridor as essential spaces and not optional, regardless of unit size. Also, transparent, and visible balconies, especially in dense urban areas, are incompatible with the Iranian lifestyle and should be adjusted to cultural beliefs and norms.

Performance of a pyramid solar still with stepped trays: Experimental approach

The present experimental work aims to enhance the daily productivity of solar stills. A stepped pyramidal still with three trays was fabricated and tested under Tanta conditions, Egypt in September 2016. The still was tested with the brine feed being uninterrupted in one experiment, and with intermittent brine supply in another experiment. For continuous brine supply, the accumulated distillate was 4.95 L. For intermittent brine supply, the accumulated distillate was 4.6 L. Per unit total area, the average daily distillate water productivity is 5.5 and 5.11 L/m2 for the continuous and the intermittent feed stills, respectively. In the two ways, the still yielded a greater productivity than that of conventional pyramid solar still which is 4.4 L/m2 .

Plasticity in mesophyll volume fraction modulates light-acclimation in needle photosynthesis in two pines

Acclimation potential of needle photosynthetic capacity varies greatly among pine species, but the underlying chemical, anatomical and morphological controls are not entirely understood. We investigated the light-dependent variation in needle characteristics in individuals of Pinus patula Schlect. & Cham., which has 19-31-cm long pendulous needles, and individuals of P. radiata D. Don., which has shorter (8-17-cm-long) stiffer needles. Needle nitrogen and carbon contents, mesophyll and structural tissue volume fractions, needle dry mass per unit total area (M(A)) and its components, volume to total area ratio (V/A(T)) and needle density (D = M(A)/(V/A(T))), and maximum carboxylase activity of Rubisco (V(cmax)) and capacity of photosynthetic electron transport (J(max)) were investigated in relation to seasonal mean integrated irradiance (Q(int)). Increases in Q(int) from canopy bottom to top resulted in proportional increases in both needle thickness and width such that needle total to projected surface area ratio, characterizing the efficiency of light interception, was independent of Q(int). Increased light availability also led to larger M(A) and nitrogen content per unit area (N(A)). Light-dependent modifications in M(A) resulted from increases in both V/A(T) and D, whereas N(A) changed because of increases in both M(A) and mass-based nitrogen content (N(M)) (N(A) = N(M)M(A)). Overall, the volume fraction of mesophyll cells increased with increasing irradiance and V/A(T) as the fraction of hypodermis and epidermis decreased with increasing needle thickness. Increases in M(A) and N(A) resulted in enhanced J(max) and V(cmax) per unit area in both species, but mass-based photosynthetic capacity increased only in P. patula. In addition, J(max) and V(cmax) showed greater plasticity in response to light in P. patula. Species differences in mesophyll volume fraction explained most of the variation in mass-based needle photosynthetic capacity between species, demonstrating that differences in plastic adjustments in mass-based photosynthetic activities among these representative individuals were mainly associated with contrasting investments in mesophyll cells. Greater area-based photosynthetic plasticity in P. patula relative to P. radiata was associated with larger increases in M(A) and mesophyll volume fraction with increasing irradiance. These data collectively demonstrate that light-dependent increases in mass-based nitrogen contents and photosynthetic activities were associated with an increased mesophyll volume fraction in needles at higher irradiances. They also emphasize the importance of light-dependent anatomical modifications in determining needle photosynthetic capacity.

Light-acclimation of cladode photosynthetic potentials in Casuarina glauca: trade-offs between physiological and structural investments.

Many arid and saline habitat species possess sparse canopies with cylindrical foliage that is considered relatively invariable along environmental gradients. However, even in sparse canopies strong gradients of light develop between the canopy top and bottom. We studied structural and photosynthetic acclimation to within-canopy light gradient in Casuarina glauca Sieb. ex Spreng., the photosynthetic organs of which are cylindrical cladodes. Seasonal average integrated quantum flux density (Qint) varied 25-fold between the canopy top and the canopy bottom. Cladode cross-sectional shape was unaffected by irradiance, but cladode dry mass per unit total area (MA) varied 2-fold within the canopy light gradient. This resulted primarily from light-dependent changes in cladode thickness (volume to total area ratio,V / AT) and to a lesser extent from changes in cladode density (D, MA = DV / AT). Nitrogen content, and the volume of mesophyll per unit surface area increased with increasing Qint and V / AT, resulting in positive scaling of foliage photosynthetic potential (capacity of photosynthetic electron transport and maximum Rubisco carboxylase activity per unit area) with light. However, nitrogen content per unit dry mass and the volume fraction of mesophyll decreased with increasing irradiance. This was explained by greater fractional investment in mechanical tissues in cladodes with greater volume to surface area ratio. This trade-off between photosynthetic and support investments reduced the cladode photosynthetic plasticity. Our study demonstrates a significant acclimation potential of species with cylindrical foliage that should be included in larger-scale carbon balance estimations of arid and saline communities.