A fully integrated,highly linear CMOS T/R switch for X‐Band phased array radars

This paper presents the design and implementation of a single‐pole, double‐throw transmit/receive (T/R) switch for X‐Band (8–12 GHz) phased array radar applications. The T/R switch was fabricated in a 0.25‐µm SiGe BiCMOS process and occupies 0.44‐mm² chip area, including pads. The design focuses on the techniques, primarily, to achieve higher power handling capability (P_1dB), along with higher isolation and better insertion loss (IL) of the T/R switch. These techniques include resistive‐body floating, using on‐chip impedance transformation networks and DC biasing of all terminals of the T/R switch. In addition, optimization of transistor widths and parallel resonance technique are used to improve IL and isolation, respectively. All these design techniques resulted in a measured IL of 3.6 dB, isolation of 34.8 dB and IP_1dB of 28.2 dBm at 10 GHz. The return losses at both input and output ports are better than 16 dB from 8 to 12 GHz. To our knowledge, this paper presents the single‐ended CMOS T/R switch with the highest IP_1dB, competitive isolation and comparable IL at X‐Band, compared to other reported works in the literature and attributed to the unique design methodologies and techniques. Copyright © 2012 John Wiley & Sons, Ltd.     

Efects of Die Corner Radius and Temperature on the Formability of AA7075-T6 Alloy

This study focused on the formability of aluminium alloy（7075-T6） sheets through hydroforming route. Formability of these sheets was tested using a warm forming setup at three diferent temperatures and four diferent die corner radii. Forming limit diagrams（FLD） were generated by measuring the grids of the sheet formed. The results show that the forming limit of AA7075-T6 can be significantly improved when the blank was heated to 140–250℃. It was also observed that as the temperature increases above 140℃, dome height began to decrease. Also the results indicated that both the die corner radius and temperature have a significant efect on the stress-strain curve and warm forming of AA7075-T6 sheets. Thus, with the temperature increased from room temperature（RT） to 140℃, the flow stress decreased and the strain increased, hence, the formability is enhanced. However, further increase in temperature causes decreases the flow stress and strain. Similar changes of the flow curve were seen in die corner radius. Decreasing the die corner radius decreases the flow stress and increase the strain. Moreover, an equation was obtained by establishing correlations between the experimental parameters and their results. In this way, it became possible to make predictions.     

Pathogen Re-Growth in UASB Effluent Disinfected By UV,O3, H2O2, and Advanced Oxidation Processes

Disinfection of anaerobically treated effluent (UASB) was carried out to eliminate the enteric pathogens by using UV irradiation, peracetic acid, H₂O₂, O₃ and advanced oxidation processes (O₃/H₂O₂, O₃/UV and H₂O₂/UV). Re-growth potential of these pathogens was monitored in terms of time and temperature. Inactivation of pathogens by ozone at the rate of 300 mg/h for 20 minutes approached 99%. UV irradiation resulted in 99% pathogen removal at irradiation time of 120 seconds. A dose of 170 mg/L H₂O₂ eliminated more than 99% pathogens. Samples disinfected with UV, H₂O₂ and O₃ showed gradual re-growth with an increase in time and temperature (from 20 to 35°C). However, disinfection with AOPs proved to be the most effective tool resulting in reduction of treatment time taken by individual processes, also the disinfected samples showed minimal re-growth revealing the superiority of their combined effects.     

Osteoporosis after spinal cord injury

Immobilisation secondary to spinal cord injury (SCI) is associated with marked and rapid atrophy of trabecular bone. The purpose of this study was to evaluate bone mineral density (BMD) in both the upper and lower extremities following SCI sustained for various lengths of time and to correlate the BMD to the level of the lesion, time from injury, spasticity and serum calcium, phosphorus and alkaline phosphatase (ALP) levels. A study was undertaken in 41 SCI patients with a mean age of 35.8 +/- 12.7 years. A significant difference in BMD between upper and lower extremities of the paraplegics were found. BMD of upper and lower extremities were similar in tetraplegies. The BMD values were significantly different when the upper extremity scores of paraplegics and tetraplegics were compared but BMD scores of the lower extremities were similar in the two groups. The decrease in BMD was less in the spastic patients when compared to the flaccid group. There was a positive correlation between time from injury and the degree of BMD deficit in the paralysed areas. In the whole group of patients a significant positive correlation was found between the duration of SCI and serum ALP levels.     

Industrial use of conglomerate from the Kayranlik Mountains, Turkey

The Kayranlik Mountain (Goksun) in Kahramanmaras is a rich resource of an attractive conglomerate with many uses in the construction industry including blocks, shaped stones, pavement, sidewalks and landscape architecture. The paper reports a study to assess their compliance with the relevant Turkish and European Standards and provides correlations between the uniaxial compressive strength, flexural strength, Brazilian tensile strength, water absorption, abrasion and density.     

Effect of Si on austenite stabilization,martensite morphology,and magnetic properties in Fe-26%Ni-x%Si alloys

The effect of Si on the austenite stabilization, martensite morphology, and magnetic properties in Fe-26%Ni-x%Si (x=3.5, 5, and 6) alloys have been studied by means of transmission electron microscopy (TEM) and M?ssbauer spectroscopy techniques. TEM observations reveal that the martensite morphology is closely dependent on the Si content. The volume fraction changes of martensite and austenite phases, the hyperfine magnetic field, and isomer shift values have been determined by Mssbauer spectroscopy. The M...     

Changes during ripening in chemical composition,proteolysis, volatile composition and texture in Kashar cheese made using raw bovine,ovine or caprine milk

Kashar cheeses were manufactured from pure ovine (OV), bovine (BV) and caprine (CP) milk, and the chemical composition, cheese yield, proteolysis, hardness, meltability and volatile composition were studied during 90 days. Gross chemical composition, cheese yield and level of proteolysis were higher in OV cheeses than those of BV or CP cheeses. Glu, Val, Leu, Phe and Lys were the most abundant free amino acids (FAA) in the samples, and the concentrations of individual FAA were at the highest levels in OV cheeses with following BV and CP cheeses. Urea‐PAGE patterns and RP‐HPLC peptide profiles of the BV cheeses were completely different from the small ruminants’ milk cheeses (OV or CP). Higher and lower hardness and meltability values were observed in CP cheeses, respectively. OV cheeses resulted in higher levels of the major volatile compounds. In conclusion, the Kashar cheese made using OV milk can be recommended due to high meltability, proteolysis and volatiles.     

Synthesis of polyacrylamide hydrogels as p–n‐junction with ionic charge carriers

Three different designs for p–n junctions were formed with p‐and n‐type polyacrylamide hydrogels (PAAm) doped with positive (Na⁺) and negative (Br^?) ions as charge carriers. First, previously synthesized p‐and n‐type gels in slab forms were contacted physically with together. Second, having synthesized p‐type gel, n‐type pregel solution was poured onto p‐type slab gel for synthesis. Thus, p‐and n‐type gels were synthesized as to be contacted chemically together. Third, first p‐type and n‐type pregel solutions were mixed together, then the mixing was poured into a pot to form a layer, and then the reaction was performed under an electric field for directing the dopants on the opposite sides. The rectification efficiencies of all these junctions were discussed in detail. POLYM. ENG. SCI., 54:2799–2805, 2014. © 2013 Society of Plastics Engineers