Designing Simplicity to Achieve Technological Improvement: The General Electric J79 Turbojet Engine; Innovations, Achievements and Effects

With the beginning of powered, manned flight, the piston engine drove a propeller or multiple propellers to provide the thrust for lift required to overcome the forces of drag and gravity for flight. As aircraft speeds gradually increased over time, the power needed to overcome the aerodynamic inefficiencies of the propeller to greater speeds and altitudes were quickly realized as a hindrance to the potential of aircraft. With the turbojet engine, this new mechanism and subsequent aerodynamic changes revolutionized aircraft to increased speeds and altitude never before achievable with a piston engine. The United States, after acquiring further and more extensive turbojet engine knowledge from the British during World War II, steadily developed the technology. In a relatively brief amount of time, the turbojet was able to power aircraft reliably beyond the speed of sound. The General Electric axial flow J79 turbojet engine generated a lasting technological innovation with the first use of production ready variable incidence stator vanes that allowed jet engines to begin to overcome compressor stall. Compressor stall can occur as air flows through the jet engines various air compressing guide and stator vanes with low air pressure building just behind a given blade. The low pressure air cell can cause damaged vanes; build to the point of causing a rotational stall which critically impedes the rotation of the engine, can migrate to the combustion chamber starving the fuel of oxygen needed for ignition, or cause the complete reversal of air flow within the engine. These events can cause minor to catastrophic engine damage or even complete engine failure. Variable incidence stator vanes were no longer static but were adjustable to allow the optimum angle of airflow around the various vanes and thus controlled the compressibility of the airflow through the engine reducing the likelihood of stalls. The use of the this variable stator design within the J79 turbojet allowed the engine to be smaller in diameter, removed complexity, and weighed considerably less than other competing turbojet engines of the time, laying the groundwork for a production run of over thirty years and speeds exceeding Mach 2, or twice the speed of sound. The purpose of this study is to analyze the General Electric J79 Turbojet engine as it relates to its contemporary turbojet engines, the aircraft it powered, and the effects for General Electric and the military powerplant industry. Additionally, the purpose of this study is to illustrate how the engine helped assist aircraft designers and their companies to satisfy Armed Forces proposals for increased speeds, payloads, systems and the missions to meet a national philosophy of deterrence of a newly perceived threat during the Cold War with the Soviet Union and her Warsaw Bloc allies

A Bio-Logical Theory of Animal Learning

This article provides the foundation for a new predictive theory of animal learning that is based upon a simple logical model. The knowledge of experimental subjects at a given time is described using logical equations. These logical equations are then used to predict a subject’s response when presented with a known or a previously unknown situation. This new theory suc- cessfully anticipates phenomena that existing theories predict, as well as phenomena that they cannot. It provides a theoretical account for phenomena that are beyond the domain of existing models, such as extinction and the detection of novelty, from which “external inhibition” can be explained. Examples of the methods applied to make predictions are given using previously published results. The present theory proposes a new way to envision the minimal functions of the nervous system, and provides possible new insights into the way that brains ultimately create and use knowledge about the world

Protein Expr Purif

E6 is a small oncoprotein involved in tumorigenesis induced by papillomaviruses (PVs). E6 often recognizes its cellular targets by binding to short motifs presenting the consensus LXXLL. E6 proteins have long resisted structural analysis. We found that bovine papillomavirus type 1 (BPV1) E6 binds the N-terminal LXXLL motif of the cellular protein paxillin with significantly higher affinity as compared to other E6/peptide interactions. Although recombinant BPV1 E6 was poorly soluble in the free state, provision of the paxillin LXXLL peptide during BPV1 E6 biosynthesis greatly enhanced the protein's solubility. Expression of BPV1 E6/LXXLL peptide complexes was carried out in bacteria in the form of triple fusion constructs comprising, from N- to C-terminus, the soluble carrier protein maltose binding protein (MBP), the LXXLL motif and the E6 protein. A TEV protease cleavage site was placed either between MBP and LXXLL motif or between LXXLL motif and E6. These constructs allowed us to produce highly concentrated samples of BPV1 E6, either covalently fused to the C-terminus of the LXXLL motif (intra-molecular complex) or non-covalently bound to it (inter-molecular complex). Heteronuclear NMR measurements were performed and showed that the E6 protein was folded with similar conformations in both covalent and non-covalent complexes. These data open the way to novel structural and functional studies of the BPV1 E6 in complex with its preferential target motif

Bacterial Flagella: Twist and Stick, or Dodge across the Kingdoms

The flagellum organelle is an intricate multiprotein assembly best known for its rotational propulsion of bacteria. However, recent studies have expanded our knowledge of other functions in pathogenic contexts, particularly adherence and immune modulation, e.g., for Salmonella enterica, Campylobacter jejuni, Pseudomonas aeruginosa, and Escherichia coli. Flagella-mediated adherence is important in host colonisation for several plant and animal pathogens, but the specific interactions that promote flagella binding to such diverse host tissues has remained elusive. Recent work has shown that the organelles act like probes that find favourable surface topologies to initiate binding. An emerging theme is that more general properties, such as ionic charge of repetitive binding epitopes and rotational force, allow interactions with plasma membrane components. At the same time, flagellin monomers are important inducers of plant and animal innate immunity: variation in their recognition impacts the course and outcome of infections in hosts from both kingdoms. Bacteria have evolved different strategies to evade or even promote this specific recognition, with some important differences shown for phytopathogens. These studies have provided a wider appreciation of the functions of bacterial flagella in the context of both plant and animal reservoirs

Effect of CER on DRL responding

The effect of CER on DRL 16 was studied in four rats. All Ss showed complete CER suppression after five CER trials, together with some unconditioned post-shock suppression. This post-shock suppression showed complete recovery in all Ss after 10 days of five CER trials per day, but complete CER suppression continued throughout