Reduction

This is a contribution to the encyclopedia of systems biology on reduction

Reduction

Reduction and reductionism have been central philosophical topics in analytic philosophy of science for more than six decades. Together they encompass a diversity of issues from metaphysics and epistemology. This article provides an introduction to the topic that illuminates how contemporary epistemological discussions took their shape historically and limns the contours of concrete cases of reduction in specific natural sciences. The unity of science and the impulse to accomplish compositional reduction in accord with a layer-cake vision of the sciences, the seminal contributions of Ernest Nagel on theory reduction and how they strongly conditioned subsequent philosophical discussions, and the detailed issues pertaining to different accounts of reduction that arise in both physical and biological science (e.g., limit-case and part-whole reduction in physics, the difference-making principle in genetics, and mechanisms in molecular biology) are explored. The conclusion argues that the epistemological heterogeneity and patchwork organization of the natural sciences encourages a pluralist stance about reduction

Pohlmeyer reduction revisited

A systematic group theoretical formulation of the Pohlmeyer reduction is presented. It provides a map between the equations of motion of sigma models with target-space a symmetric space M=F/G and a class of integrable multi-component generalizations of the sine-Gordon equation. When M is of definite signature their solutions describe classical bosonic string configurations on the curved space-time R_t\times M. In contrast, if M is of indefinite signature the solutions to those equations can describe bosonic string configurations on R_t\times M, M\times S^1_\vartheta or simply M. The conditions required to enable the Lagrangian formulation of the resulting equations in terms of gauged WZW actions with a potential term are clarified, and it is shown that the corresponding Lagrangian action is not unique in general. The Pohlmeyer reductions of sigma models on CP^n and AdS_n are discussed as particular examples of symmetric spaces of definite and indefinite signature, respectively.Comment: 45 pages, LaTeX, more references added, accepted for publication in JHE

Cutting Fluid Management: Small Machining Operations

This manual has been organized into seven sections. Section 1 introduces the reader to fluid management and potential rewards of a fluid management program. Section 2 provides a brief review of cutting fluid systems, functions of cutting fluids and characteristics a fluid should have in order to perform safely and effectively. Section 3 presents information on cutting fluid selection and types of cutting fluids available. It covers the four types of metalworking fluids used today, their advantages and disadvantages, and factors to consider in selecting a fluid. Section 4 is the main focus of this manual. It discusses the four integral components of fluid management–administration, monitoring, maintenance, and recycling. It provides information on practices that can be readily adopted to prevent the onset of fluid degradation, maintain fluid quality, extend fluid service life and reduce waste. Section 5 presents information on waste management and disposal. It provides an overview of environmental regulations that pertain to spent cutting fluid and reviews possible disposal alternatives for waste cutting fluid. Section 6 looks at alternatives to cutting fluids. Advantages and disadvantages of dry machining and other existing technology is examined, and information is presented on a number of emerging technologies that can extend cutting fluid life or even eliminate traditional cutting fluids altogether. Section 7 provides detailed information on the subject of worker health and safety, and provides sources for additional information on this subject. Appendix A contains several case studies. These studies demonstrate how the many pieces of a cutting fluid management system can be fit together to provide an effective, economical and efficient operation.https://scholarworks.uni.edu/iwrc_facbook/1005/thumbnail.jp

Handbook of Environmental Regulations for Agribusiness

This Handbook is intended to provide the information needed for agribusiness facilities to comply with state and federal environmental regulations. Staff at the Iowa Waste Reduction Center wrote the Handbook. Technical input and review was provided by Dan Eddinger, Nebraska Department of Enviromental Quality; Mark Lohafer and John Whipple, Iowa Department of Land and Agricultural Stewardship; staff at the United States Environmental Protection Agency (U.S.EPA) Region 7; staff at the Iowa Department of Natural Resources (IDNR); and Chris Murray, Agribusiness Association of Iowa.https://scholarworks.uni.edu/iwrc_facbook/1009/thumbnail.jp

Compliance Calendar/Logbook for Bulk Gasoline Plants: Less than 19,999 Gallons/Day Throughput

EPA has new requirements for Gasoline Distribution Bulk Terminals, Bulk Gasoline Plants and Pipeline Facilities under 40 CFR Part 63 Subpart BBBBBB (NESHAP 6B) to reduce air pollution. This calendar has been developed to assist Bulk Gasoline Plants in complying with NESHAP 6B. Additional Iowa specific NESHAP 6B rules are discussed later.https://scholarworks.uni.edu/iwrc_facbook/1004/thumbnail.jp

Golf Course Pollution Prevention Guide

According to the Environmental Protection Agency (EPA), pollution prevention can be defined as: “The use of materials, processes, or practices that reduces or eliminates the creation of pollutants or wastes at the source.” Pollution prevention represents a shift away from the old school of thought, “pollution control,” in which waste was not dealt with until after it was generated. Through pollution prevention, we look at the processes that generate the waste to see if we can avoid creating a waste in the first place, or at least reduce the hazardous nature of the waste. When this is not possible, the next best solution to prevent wastes from having a negative impact on the environment is through careful management and recycling. This manual will help golf course maintenance staff identify areas where pollution prevention techniques can be applied in a practical manner. Each section presents a waste type common to golf courses accompanied by pollution prevention recommendations. Although the focus of this manual is on pollution prevention, regulatory information is given as necessary where it impacts pollution prevention practices and to illustrate how pollution prevention can help reduce regulatory requirements.https://scholarworks.uni.edu/iwrc_facbook/1008/thumbnail.jp

Chemical reduction of hexavalent chromium (VI) in soil slurry by nano zero valent iron

The increasing industrial development of recent decades has lead to the production of increasing quantities of waste containing heavy metals, elements often harmful to the environment, which in the past were not properly disposed of, thus inducing soil and groundwater pollution. In particular, chromium (Cr) and its derivatives are largely used in industries such as textiles, electronics, metallurgy, tanneries. Consequently, large quantities of this element were released into the environment due to leakage or incorrect disposal. Chromium is a transition element present in nature in three stable forms: metallic Cr, trivalent Cr(III) and hexavalent Cr(VI). Metallic Chromium is rarely found in nature, mainly as natural chrome metallic inclusions in diamonds, fragments of as meteorites and metal alloys in fluvial deposits. The trivalent form is characterized by a relatively low toxicity, while the hexavalent chromium present in different compounds of industrial origin, is considered highly toxic towards the respiratory system and carcinogenic. In the present work, lab experiments of Cr(VI) contaminated soil clean-up by chemical reduction with nanoparticles of zero valent iron (nZVI) are presented and discussed. The aim of the work was to optimize the main operative parameters of the reduction process (pH, nZVI concentration, liquid/solid ratio). Cr(VI) reduction using nZVI was found to obey a pseudo-first-order kinetic: the kinetic constant depended upon the nZVI: Cr(VI) ratio. The use of nZVI in combination with sodium dithionite was also studied, by performing tests in batch conditions at pH = 1.3, in order to assess the optimal ratio between nZVI and Cr(VI), and between dithionite and Cr(VI). The results obtained showed an increase of Cr(VI) reduction rate with respect to the tests carried only with nZVI: for long treatment times, up to 24 hours, an almost total removal of Cr(VI) was achieved when a large excess of reagents was used