This paper investigate a low altitude air-to-ground channel over a sea surface in the tropical region at C band. It is found that, compared to a high altitude air-to-ground channel where a free space propagation condition can be assumed, the sea surface reflection and other multipath propagation phenomena for lower altitude air-to-ground channel can readily be observed. Therefore, for low altit...

since nox family, one of the most important causes of air pollution, is the primary source of acid rains, ozone layer depletion, and breathing disorders, mitigation of these pollutants is now a global concern. in the off-gases of internal combustion engines running with oxygen excess, non-thermal plasmas (ntps) have an oxidative potential, which results in an effective conversion of no to no2. ...

The aim of this study was to establish whether the air-conditioning system in buses constitutes an additional source of indoor air contamination with fungi, and whether or not the fungi concentration depends on the period from the last disinfection of the system, combined with replacement of the cabin dust particle filter. The air samples to fungi analysis using impact method were taken in 30 b...

Microclimate in open space affected by the urban layout and spatial forms plays an important role in the outdoor comfort, thus the outdoor activities based on the comfort sensation will directly affected by the spatial forms. An outstanding open space should satisfy different requirements of outdoor activities and create relatively comfortable place.Most studies have been conducted on the...

Subcutaneous emphysema in the head and neck is a well known clinical condition. It is an uncommon clinical complication of dental treatment caused by forceful injection of air into the loose connective tissue below the dermal layer. The trapped air is often limited by subcutaneous space in the head and neck. This paper presents a clinical case in which subcutaneous emphysema developed immediate...

We report a case of spontaneous interlobar pneumothorax, an uncommon condition. The diagnosis was suspected from the frontal chest X-ray, which showed an incompletely circumscribed air-containing space, with a fluid level. The diagnosis was confirmed by the lateral projections of standard X-ray and tomography, and by thoracic computed tomography (CT). Such air-fluid levels should not be confuse...

Pneumocephalus is a rare consequence of epidural anesthesia, which may occur following inadvertent or unidentified dural puncture when the loss of resistance to air technique is applied to identify the epidural space. Headache is the most common symptom presented in this condition, usually with sudden onset. This case report describes an unusual presentation of diffuse pneumocephalus after an u...

In this paper we get estimation of the absolute condition number a Hilbert space operator, which is related with the outer generalized inverse of a given operator.