Hydrofluoric acid (HF) is a catalyst for the production of linear alkyl benzene (LAB). In this research, the corrosion and perforation in the overhead line of HF neutralization section in Bistoun Petrochemical Company (BPC), in Iran was investigated. The accumulation of sediment and under deposit corrosion has resulted in the perforation of the mentioned line. The main causes of failure were explored by visual checking, chemical characterizations, scanning electron microscopy (SEM), and X-Ray fluorescence (XRF). The effects of process conditions, pipeline design, water content, and oxygen amounts were studied. Corrosion and perforation in the line is based on the composition of the liquid or gases passing through the line and operating conditions. The reverse return of water vapors contaminated with KOH from relief gas scrubber to the overhead line can accelerate the corrosion. Lastly, the suggestions have been proposed for troubleshooting, prevention from failure in the line, and HF leakage.

In a taxonomic study on the genus Podosphaera sect. Sphaerotheca, several newly collected specimens and all specimens from fungus collection of the Ministry of Jihad-e- Agriculture, were examined. A total of 13 taxa including Podosphaera aphanis var. aphanis, P. aphanis var. hyalina, P. balsaminae, P. dipsacacearum, P. erodii, P. euphorbiae, P. ferruginea, P. fugax, P. fusca, P. macularis, P. plantaginis, P. pannosa and P. xanthii were identified. Morphology of the thin-walled apical portion of the asci (oculus) was examined among taxa. The results revealed the usefulness of this feature for identification of some taxa as shown by other researchers. On the basis of morphological characteristics of P. aphanis var. hyalina, it was shown that taxon differrs from type variety in having short appendages, ascus size as well as wider oculi. It seems there is enough evidence to raise this variety as a separate species. Hence, it is necessary to investigate more characteristics especially ribosomal DNA or other genes sequencing to make an indisputable decision. Plant species viz. Hieracium sp., Potentilla hirta and Scabiosa persica are recorded as new hosts for Erysiphaceae of Iran. A key for the Iranian taxa of this section is provided.

Mustard chemical warfare has been neutralized by solution of sodium hydroxide and sodium hypochlorite or calcium hypochlorite. Sulfur mustard has been hydrolyzed with water, and converted to thiodiglicol.

Sarin chemical warfare has been neutralized by solution of sodium hydroxide, sodium carbonate and potassium hydroxide at room temperatures and pH of 13. The hydrolysis of sarin is increased by increasing of pH, and it is strongly depends on pH. The hydrolysis reaction of sarin is as follows...

Since a secure voice or data session is very important in military HF communication, it needs a HF modem designed with cipher capability. Whereas multipath and Doppler affection are very adverse in HF sky-wave mode, so the production of a robust modem is essential for military application to compensate channel distortion. Then channel estimation block is very important and this paper proposes an enhanced method for channel estimation. The OFDM pilot based channel estimation with wiener filtering is a robust method that estimates channel excellently with minimum pilot density. The result show that proposed method can increase bit rate with decrement in pilot density, which allows use of a stronger channel coding and subsequently a lower bit error rate. Simulation shows that the bit-error rate of the proposed method passes the American military standards.

Introduction: Diagnosis of thyroid lesions at the time of operation can help the physician in decision making to select appropriate treatment and to prevent total thyroidectoy and its complications. Using intraoperative cytology and frozen section prepare this opportunity. The main aim of this study is the assessment of the diagnostic value study of intra operative cytology (IOC) as an alternative to Frozen section (FS) in thyroid lesions. This is a cross-sectional study, conducted in 2000, on 126 thyroidectomy specimens in Alzahra hospital. Material and methods: 3 slides, one by frozen section, one by touch print after fixation, and another by paraffin section (PS) were prepared. FS and IOC results were compared with those of PS. Results: Sensitivity and specificity of FS for neoplastic lesions were 79, 97%, and for nonneoplastic lesions 97% and 79%. The validity of FS for neoplastic and nonneoplastic lesions was 77 percent. Sensitivity and specificity of IOC for neoplastic were 79, 91% and for nonneoplastic lesions 91 and 79%, and validity for neoplastic and nonneoplastic 71 and 73% respectively. Conclusion: FS and IOC have equal sensitivity and specificity in diagnosis of neoplastic and nonneoplatic lesions and FS can be replaced by IOC.