Optimization of a ventilation system integrated into a window frame using CFD simulations

A decentralized ventilation system has the potential to decrease the pressure drop in a ventilation system and consequently, increase the efficiency of the system and building skin. Including a decentralized ventilation system in a window cavity allows independent regulation of the fresh air quality in each room and can be easily installed without any additional brickwork. In this study, a novel ventilation system integrated into a window-frame is examined and the most critical region regarding pressure drop is identified using computational fluid dynamic (CFD) simulations. The entire fresh air channel including the optimized section is compared with the original volume regarding system resistance and satisfaction of the required airflow according to Swiss standards. The results suggest a relocation of the restricting control unit and an increased cross-section to decrease the air velocity and the pressure drop. The simulations predicted that the required airflow for sufficient indoor air quality is exceeded using the optimized geometry

Terata of two legume species with radialized corolla: some correlations in floral symmetry

Most papilionoid legumes (Leguminosae) are characterized by zygomorphic flowers. Features of monosymmetry are inherent to all floral whorls. We compare flowers of two species of papilionoid legumes with anomalously radialized corollas. Except for vexilloid mode of all five petals, these flowers were remarkable with their free androecium and (in case of Clitoria ternatea) actinomorphic calyx. The symmetry of the gynoecium remains unaltered. These correlations point at a strong interrelation between perianth and androecium symmetry control, possibly governed by the same genes. A review on floral symmetry in related papilionoid genera indicates that staminal fusion is only possible in case of a discernible adaxial petal (flag). This rule has some exceptions which contribute to the idea of independent recurrent origin of monosymmetry in different leguminous clades

Relationships among the A Genomes of Triticum L. Species as Evidenced by SSR Markers, in Iran

The relationships among 55 wheat accessions (47 accessions collected from Iran and eight accessions provided by the Institute of Plant Biology of the University of Zurich, Switzerland) belonging to eight species carrying A genome (Triticum monococcum L., T. boeoticum Boiss., T. urartu Tumanian ex Gandilyan, T. durum Desf., T. turgidum L., T. dicoccum Schrank ex Schübler, T. dicoccoides (Körn. ex Asch. & Graebner) Schweinf. and T. aestivum L.) were evaluated using 31 A genome specific microsatellite markers. A high level of polymorphism was observed among the accessions studied (PIC = 0.77). The highest gene diversity was revealed among T. durum genotypes, while the lowest genetic variation was found in T. dicoccoides accessions. The analysis of molecular variance (AMOVA) showed a significant genetic variance (75.56%) among these accessions, representing a high intra-specific genetic diversity within Triticum taxa in Iran. However, such a variance was not observed among their ploidy levels. Based on the genetic similarity analysis, the accessions collected from Iran were divided into two main groups: diploids and polyploids. The genetic similarity among the diploid and polyploid species was 0.85 and 0.89 respectively. There were no significant differences in A genome diversity from different geographic regions. Based on the genetic diversity analyses, we consider there is value in a greater sampling of each species in Iran to discover useful genes for breeding purposes

Thermal resistance of ventilated air-spaces behind external claddings; definitions and challenges (ASHRAE 1759-RP)

The presence of an air-space within a building envelope is known to have a varying contribution to the overall thermal performance of the wall assembly due to the combined effect of convection and radiation in the air cavity. In particular, the thermal resistance of a ventilated air-space can vary significantly depending on multiple environmental and thermo-physical parameters. Although the thermal resistance of enclosed air-spaces in the building structures has been thoroughly investigated in the literature, it has not been defined for a ventilated cavity. This paper aims to introduce the plausible definitions of the thermal resistance of a vertical ventilated air-space behind external cladding systems. Both theoretical and applied formulations are provided and compared. The energy balance method is used to model the steady-state heat transfer through two types of traditional external wall systems (i.e., brick and vinyl siding) in summer and winter conditions. A range of air exchange rates in the cavity is examined, and the effect of the presence of reflective insulation in the air-space on the thermal resistance of the air gap is analyzed. The results show that the presence of a ventilated cavity in the wall assembly can influence the thermal performance of the building envelope. In particular, the effective thermal resistance of a ventilated air-space behind a brick cladding wall could be between 0.17 and 1.85 times the thermal resistance of the cladding in the range of air change rate in the cavity from 0 to 100 1/h. The effective thermal resistance of the ventilated air gap behind vinyl siding could reach up to 9 times the thermal resistance of the cladding

Review on ventilation rates in the ventilated air-spaces behind common wall assemblies with external cladding

For many decades, ventilated cavities in wall assemblies of buildings have been essential for creating moisture resilient constructions by allowing airflow within the air gap to promote drying. In addition to that, the airflow in the cavity can enhance the thermal performance of the building envelope, depending on the air change rate and outdoor conditions. Therefore, the effective factors on the air change rate in the ventilated cavity behind common wall assemblies with external cladding are specified in the present study. As a first step, the analysis of the stack effect and wind effect as mechanisms that drive the airflow in the ventilated air-space available in the literature is reviewed. Moreover, the hydraulic network of pressure losses along the wall cavity is analyzed, and various correlations for the loss factors are described. Despite separate studies analyzing the effect of the ventilated cavity on moisture dissipation through water-permeable materials, a comprehensive overview of the airflow rates behind the ventilated wall assemblies is still lacking. Therefore, as the second step in this paper, existing methods of predicting air-change rates behind the ventilated cladding systems are classified and compared with the measured data. The amount of air change rate in the ventilated air gaps behind brick, cement & stucco, ceramic, wood, and other types of external facades are studied through a comprehensive review of relevant publications. Based on the observations, the maximum air change rate in the air-spaces behind open joint claddings such as the ceramic wall is nearly two times compared to the closed joint claddings such as the brick wall

Measuring the effective thermal resistance of ventilated air-spaces behind common wall assemblies: Theoretical uncertainty analysis and recommendations for the hot box method modifications (ASHRAE 1759-RP)

A well-designed ventilated wall that incorporates air-space behind cladding can reduce energy use for conditioning buildings by adding a thermally resistive layer. The scarcity of thermal performance data and standardized test methods is a particular barrier for practitioners to implement ventilated air gaps behind the facades. The current standardized test method to evaluate the thermal performance of a wall structure, such as ASTM 1363-19, does not consider the effect of the ventilated air-space behind external claddings. Therefore, testing and design recommendations are required to account for the impact of ventilation airflow on the thermal resistance of vertical air-spaces behind common cladding materials. In this study, the theoretical uncertainty analysis of the effective thermal resistance of the ventilated cavity is performed for a steady-state condition. The results revealed that temperature sensors with an absolute uncertainty of ±0.18°F (±0.1 °C) and heat flux sensors with a relative uncertainty of 3% or lower are required to capture a wide range of the effective thermal resistance of the ventilated air gap. Thereafter, based on the uncertainty of temperature and heat flux measurements, the modifications of the ASTM C1363-19 test method to account for the airflow effects on the thermal performance of the wall assembly are proposed. A detailed description of the experimental setup is provided, and protocols for collecting, analyzing, and evaluating data are suggested. An example demonstrating how the proposed method can be practically used to measure the thermal resistance of a ventilated air-space is also presented

Enoxaparin Plus Ticlopidine: An Effective Combination Therapy for Intracardiac Thrombi in Thalassemia Intermedia

Objective: Patients with thalassemia intermedia have an increased risk of thrombotic events as compared to the general population. Case Presentation:We describe two cases of thalassemia intermedia with intracardiac thrombi who failed to response to traditional anticoagulation therapy with Unfractionated Heparin and Aspirin; but thrombolysis occurred following combination therapy with Ticlopidine and Enoxaparin. Conclusion: Our experience in patients shown combination of Enoxaparin and Ticlopidine is effective for treatment of ventricular thrombus in TI patients

A taxonomic revision of Eremopoa persica (Trin.) Roshev. and E. songarica (Schrenk.) Roshev. using morphological features and cytological data

A total of 58 accessions of Eremopoa persica and E. songarica belongigng to the family Poaceae and tribe Festuceae (Poacea) were morphologically studied. Three polidy levels diplo, triplo and tetraploid were counted from chromosome number counting of 7 accessions of the root tips as: 2n=14 and 21 for E. persica and 2n=28 for songarica. Based on the results of this study it could be suggested that the two Eremopoa species (E. persica and E. songarica) might to be considered as two varieties of E. persica

Karyotype analysis of some species of Vicia L. section Vicia (Fabaceae Lindl.) in Iran

The somatic chromosome numbers and karyotypic analysis of six taxa belonging to Vicia sect. Vicia (Fabaceae) were performed. We found three basic chromosome numbers (x=5, 6 and 7) in this section. All of the taxa were diploid. The chromosome number of V. lathyroides, V. grandiflora, V. sativa var. cordata and V. sativa var. amphicarpa were presented for the first time in Iran. Karyotype formula was different in the taxa, so that in the taxa V. lathyroides (2n=12), V. sativa var. sativa (2n=12), V. sativa var. angustifolia (2n=12), V. sativa var. cordata (2n=10), V. sativa var. amphicarpa (2n=14), V. grandiflora (2n=14) karyotype the formula were 6st, 2m+4st, 1m+1sm+4st, 5st, 3sm+4st and 5sm+2st respectively. The taxa studied were placed in 3A (V. sativa var. angustifolia and V. grandiflora), 3B (V. sativa var. amphicarpa) and 4A (V. lathyroides, V. sativa var. sativa and V. sativa var. cordata) classes of Stebbines. Based on A1 and A2 parameters, V. grandiflora and V. sativa var. cordata had symmetrical and asymmetrical karyotypes respectively

Notes on Aegilops cylindrica (Triticeae, Poaceae) in Iran

The present paper deals with the study of the taxonomy of one hundred accessions of Aegilops cylindica collected all around the country, and also Iranian materials and type specimens and related species housed in the Natural History Museum Vienna (W), the Botanic Garden and Botanical Museum Berlin (B), were studied morphologically. The results showed that morphological traits such as length of spike, length of awn, number of spikelet in each spike, presence/absence of hair on spikelets and rachis were highly variable among the studied materials. Based on the results of this study A. cylindica was recognized as having three varieties, all new records, for Iran