The Structure and Function of the Border Parenchyma and Vein-Ribs of Certain Dicotylendon Leaves

The border parenchyma has long been recognized as a structural constant in the many kinds of angiosperm leaves. As an unbroken sheath it invests all minor veins and is an intermediary between the conductive channels and the mesophyll. Though the presence of the border parenchyma has long been known, references to it have been casual and its significance has not been adequately appreciated. The uniform presence of this sheath in an organ marked by economy of tissue has invited this attempt to evaluate its place in the foliage leaf as a whole. Schubert (24) discussed the structure of the border parenchyma in various plant families and recognized two classes of starch sheaths : those in which there was nerve parenchyma associated with the sheath, and others in which it was lacking. The former refers undoubtedly to the vein-ribs described later in the present paper while the latter is the border parenchyma proper. The nerve parenchyma , he said, was generally present in large leaves and absent in small ones. This generalization was found to be incorrect for the sixty species studied in this research. Schubert was more accurate in his suggestion that it is possible that the nerve tissue assists in the transport of assimilate

Retrofitting Gas Turbines With Computer Control.

LecturePg. 99-104Retrofitting gas turbines with microprocessor based controls has improved reliability and performance in the areas of speed control, temperature control, and load control. The rationale behind control system retrofits is described. Installation problems and benefits derived from retrofits also is discussed. The details of six heavy duty single-shaft gas turbine retrofits are presented. These turbines drive both process compressors and electric generators at the Amoco Oil Company, Texas City refinery. Turbomachinery control system retrofits can improve reliability and decrease operating costs

Hanford solid waste management system simulation

This paper describes systems analysis and simulation model development for a proposed solid waste management system at a U.S. Department of Energy Site. The proposed system will include a central storage facility, four treatment facilities, and three disposal sites. The material managed by this system will include radioactive, hazardous, and mixed radioactive and hazardous wastes. The objective of the modeling effort is to provide a means of evaluating throughput and capacity requirements for the proposed treatment, storage, and disposal facilities. The model is used to evaluate alternative system configurations and the effect on the alternatives of changing waste stream characteristics and receipt schedules. An iterative modeling and analysis approach is used that provides macro-level models early in the project and establishes credibility with the customer. The results from the analyses based on the macro models influence system design decisions and provide information that helps focus subsequent model development. Modeling and simulation of alternative system configurations and operating strategies yield a better understanding of the solid waste system requirements. The model effectively integrates information obtained through systems analysis and waste characterization to provide a consistent basis for system and facility planning

Field, capital and the policing habitus: nderstanding Bourdieu through The NYPD’s post-9/11 counterterrorism practices

This article extends existing Bourdieusian theory in criminology and security literature through examining the practices of the New York City Police Department in the post-9/11 counterterrorism field. This article makes several original contributions. First, it explores the resilient nature of the policing habitus, extending Bourdieusian criminological findings that habitus are entrenched and difficult to change. Second, this article examines the way the resilient habitus drives subordinate factions to displace dominant factions in a field’s established social hierarchy through boundary-pushing practices, a concept previously unexamined in Bourdieusian criminology. Drawing on original documentary analysis, this article uses the illustrative example of the NYPD’s post-9/11 counterterrorism practices, exploring how it sought to displace the existing social structure by using its aggressive policing habitus and an infusion of ‘War on Terror’ capital to challenge the dominant position of the FBI in the post-9/11 counterterrorism field. The NYPD’s habitus driven counterterrorism practices were novel and unprecedented, creating strain with both the FBI and local communities

A thin-slice of institutionalised police brutality: a tradition of excessive force in the Chicago Police Department

In the Chicago Police Department, a sustained tradition of tolerating violent conduct has contributed to the fostering of a police culture in which the use of force is celebrated. Evidence suggests that there has been a historical reluctance to take action to discipline officers accused of misconduct – many of whom are highly decorated veterans of the Chicago Police Department. It is the contention of this article that the long-standing endorsement of excessive force in Chicago policing has compromised officers’ ability to thin-slice, a psychological process in which people are able to draw on their experiences and socio-cultural context to make quick decisions under pressure. Instead, officers are instinctively drawn to engage in misconduct as a means to an end, with the confidence that their actions will not attract the sanction of their superiors