University of Wah

About: University of Wah is a education organization based out in Rawalpindi, Pakistan. It is known for research contribution in the topics: Per capita income & Rhizobacteria. The organization has 258 authors who have published 466 publications receiving 4719 citations.

Does Materials Technology Pay its Carbon Price

Abstract: Since new technologies largely promote materials costs in the form of high mass carbon emissions, thus the green materials technologies are the sustainable policy options to mitigate carbon emissions through carbon pricing.

Transient Stability Analysis of the IEEE-9 Bus System under Multiple Contingencies

Abstract: The determination of the transient stability of an electric power system is a crucial step in power system analysis. This paper investigates the transient stability of an IEEE-9 bus system consisting of three generators and nine buses. At first, a load flow analysis is conducted in order to determine the pre-fault conditions. Secondly, fault analysis is performed to analyze post fault conditions like the fast fault clearing time and load switching in order to determine the system stability. For transient stability analysis, Euler and Runga methods are compared and applied on the frequency and rotor angle of the system to analyze the system variations under different fault conditions. The simulations were done on the Power World Simulator (PWS) software. It is concluded that Critical Fault Clearing Time (CFCT) is a very important factor in keeping the power system within the stability bounds. A slight increase in Clearing Time (CT) from the critical value causes un-synchronism.

Development of zirconium and potassium perchlorate igniter for AP/HTPB composite propellant base bleed grain

Abstract: For effective and reliable ignition of ammonium perchlorate and hydroxyl-terminated polybutadiene (AP/HTPB) solid composite propellant base bleed (BB) grain a simple, reproducible and high-energy igniter composition were studied. Zirconium and potassium perchlorate (ZPP)-based compositions were developed with and without nitrocellulose (NC) lacquer as binder. The effects of different ratios of Zr/KClO4 were investigated by using fuse wire technique for burning rates, bomb calorimeter for calorific value and high-pressure closed vessel (CV) for pressure–time (P–t) curve, pressure maximum (Pmax), time to reach Pmax (tPmax), and rate of change of pressure change (dP/dt). It was observed that composition K-8 with fuel, oxidizer, and binder ratio of 1:1:0.02 gave reliable burning rate, calorific value, Pmax, and dP/dt. After careful analysis of combustion performance, composition K-8 was further investigated for burning rate and P–t data after 10 h of temperature conditioning at − 40 °C, + 21 °C and + 50 °C, respectively. Selected composition was then press-filled in specially designed steel igniter cups which were press-fitted in base bleed kit igniter bodies. Several static firings were performed by initiating igniter with electric squib for recording the burning time, igniter mass burning behavior, and reproducibility of successful ignition results. ZPP igniter was finally fitted in base bleed kit equipped with AP/HTPB composite propellant BB grain and tested on static as well as dynamic level by firing with 155-mm artillery projectile. Dynamic testing after temperature conditioning of complete projectile equipped with BB kit at + 21 °C, + 50 °C and − 40 °C for 24 h. Igniter provided successful ignition to base bleed grain until it achieved stable burning. All fired rounds achieved enhanced range of 30% approximately, with controlled uniform muzzle velocity and chamber pressure. ZPP igniter is recommended to be used for AP/HTPB solid composite propellant base bleed grain.

On-demand radiosynthesis of N-succinimidyl-4-[18F]fluorobenzoate ([18F]SFB) on an electrowetting-on-dielectric microfluidic chip for 18F-labeling of protein

Abstract: An all-electronic, droplet-based batch microfluidic device, operated using the electrowetting on dielectric (EWOD) mechanism was developed for on-demand synthesis of N-succinimidyl-4-[18F]fluorobenzoate ([18F]SFB), the most commonly used 18F-prosthetic group for biomolecule labeling. In order to facilitate the development of peptides, and proteins as new diagnostic and therapeutic agents, we have diversified the compact EWOD microfluidic platform to perform the three-step radiosynthesis of [18F]SFB starting from the no carrier added [18F]fluoride ion. In this report, we established an optimal microliter droplet reaction condition to obtain reliable yields and synthesized [18F]SFB with sufficient radioactivity for subsequent conjugation to the anti-PSCA cys-diabody (A2cDb) and for small animal imaging. The three-step, one-pot radiosynthesis of [18F]SFB radiochemistry was adapted to a batch microfluidic platform with a reaction droplet sandwiched between two parallel plates of an EWOD chip, and optimized. Specifically, the ratio of precursor to base, droplet volume, reagent concentration, reaction time, and evaporation time were found be to be critical parameters. [18F]SFB was successfully synthesized on the EWOD chip in 39 ± 7% (n = 4) radiochemical yield in a total synthesis time of ∼120 min ([18F]fluoride activation, [18F]fluorination, hydrolysis, and coupling reaction, HPLC purification, drying and reformulation). The reformulation and stabilization step for [18F]SFB was important to obtain a high protein labeling efficiency of 33.1 ± 12.5% (n = 3). A small-animal immunoPET pilot study demonstrated that the [18F]SFB-PSCA diabody conjugate showed specific uptake in the PSCA-positive human prostate cancer xenograft. The successful development of a compact footprint of the EWOD radiosynthesizer has the potential to empower biologists to produce PET probes of interest themselves in a standard laboratory.