Jenkins' Deliberations on Communal Conflict with the Leaders of Punjab: 1946-47 (Part-I)

Bhim Sen Sacher informed Jenkins about the destruction caused by arson in Lahore. Akbari Mandi, Chune Mandi, Chauhatta Basti, Bhagat Singh Basti, Kucha Kagzian and Pipal Vehra had been burnt down. The fire brigade could not cope with those vast and dispersed areas. If someone tried to extinguish the fire he was shot at by the police. Bhim Sen Sachar suggested that the only way to save Lahore was to impose martial law in the city. He hoped that the Governor would take that step immediately.64 Jenkins thanked Lala Bhim Sen Sachar and Gokul for their letters informing him about Lahore. Jenkins explained that fire brigade had done a good job in spite of constraints and difficulties. He believed that all communities had access to incendiary materials, and could use it without detection by traversing joined roof-tops. Throwing fire-balls from one house to another was wreaking devastation. Checking trouble of that kind was not an easy job, but searches were carried out and culprits were arrested.6

The Effect of Various Substitutions on the Microstructure and Properties of Srtio 3 -Sr 2 Nb 2 O 7 Based Electroceramics for Microwave Applications

Sr 5 Nb 4 TiO 17 is known to exhibit low loss in comparison to other compounds in the SrTiO 3 –Sr 2 Nb 2 O 7 system; therefore, the aim of this work was to investigate the effect of various cation substitutions on the phase, microstructure and electrical properties of Sr 5 Nb 4 TiO 17 for possible microwave (MW) applications. All the compositions were prepared through a mixed oxide solid state sintering route. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used for phase and microstructural analysis, and LCR meter and a vector network analyzer for the measurement of electrical properties. Compositions in the Sr 5-x Ca x Nb 4 TiO 17 (x = 0-5) series formed single phase ceramics at ~1400°C; however, at temperatures ≥1500°C, secondary phases with general formula (Sr,Ca) 6 Nb 4 Ti 2 O 20 formed along with the parent Sr 5-x Ca x Nb 4 TiO 17 phases with x = 0 – 5. Optimum MW dielectric properties (e r ~54 t f ~6.5 ppm/°C, Q u ×f o ~1166 GHz) were achieved for the ~97% dense Sr 2 Ca 3 Nb 4 TiO 17 ceramics. Compositions in the Sr 5-x La x Nb 4-x Ti 1+x O 17 (x = 0-4) series also formed single phase ceramics at 1450°C to 1550°C. Optimum values for Q u ×f o (~ 9969 GHz), e r (~ 61) and t f (~ 117 ppm/°C) were achieved for the Sr 5-x La x Nb 4-x Ti 1+x O 17 composition with x = 4 (i.e. SrLa 4 Ti 5 O 17 ). In an attempt for further improvement in the electrical properties, compositions in the SrLa 4-x A x Ti 5 O 17 series (A = Nd or Sm, x = 0 ≤ x ≤ 4) were also investigated. An analysis of the properties vs. composition plots indicated that the optimum MW dielectric properties i.e. e r ~ 54, Q u ×f o ~ 6000 GHz and t f ~ 0 ppm/°C corresponded to the SrLa 4-x Nd x Ti 5 O 17 composition with x ~ 1.6. SrLa 4-x Sm x Ti 5 O 17 compositions formed single phase ceramics at x ≤ 3 and a mixture of Sm 2 Ti 2 O 7 and SrTiO 3 at x = 4. Here again, an analysis of the results indicated that the optimum properties i.e. e r = 53, t f ~ 0 ppm/ o C and Q u ×f o = 3200 GHz corresponded to the SrLa 4- x Sm x Ti 5 O 17 composition with x~1.4. Compounds in the Sr 1-x Ca x La 4 Ti 5 O 17 (x = 0 - 1) and SrLa 4 Ti 5-x Zr x O 17 (x = 0 – 0.1) composition series exhibited e r ~53.7, Q u ×f o ~11532 GHz and t f ~-1.4 ppm/°C, and e r ~ 57.3, t f ~ +71.5 ppm/°C and Q u ×f o ~9841 GHz for x = 0.6 (Ca 2+ ) and x = 0.1 (Zr 4+ ). Consistent with previous, the substitutions of smaller cations for larger ones led to the development of fine grained microstructures indicating improved density.