Milling parameter optimization through a discrete variable transformation

Although milling is one of the most common chip metal removal processes, little has been done to aid in identifying the optimum operational conditions for milling processes. In this paper, a mathematical model for milling operations is developed and the five primary control variables identified. The model is then decomposed and an efficient optimization procedure developed for control variable identification.     

Top-down versus bottom-up forecasting strategies

Some controversy exists about the advocacy of top-down versus bottom-up forecasting strategies. Top-down forecasting refers to the process of forecasting the demand for the aggregate of items in a class and then inferring individual demands according to a percentage of the total; bottom-up refers to separately forecasting the requirements for each individual item. This paper outlines the relative advantages of each strategy and indicates the situations in which each should be preferred.     

Systematic design of robust control systems using small gain stability concepts

A systematic numerical method for designing robust controllers is developed, based on small gain stability concepts. The procedure is interactive, and makes use of analytically derived expressions for singular value gradients. The underlying theory is discussed and design examples are presented.     

Reliability analysis of production systems with buffer storage

In this paper we present a two-stage production line with buffer storage where each stage may fail in two failure modes. We consider three repair policies; namely, (I) Policy I: failures are repaired with equal probabilities, (2) Policy II: priority of repair is assigned to failures of mode 1 over mode 2, and (3) Policy III: priority of repair is placed on mode 2. Productivity of system operating under policy I is higher than that of system operating under policies II and III.Also,Policy III shows a higher productivity than Policy II.     

Incorporating L-Ascorbyl 6-Palmitate in Bread and Its Shortening-Sparing and Anti-Firming Effects

L-Ascorbyl 6-palmitate (AP) was conveniently incorporated in bread dough by gently premixing AP in vegetable oil or shortening, adding the premix with the remaining ingredients and mixing the dough at conventional speeds. Alternatively, high-speed mixing of AP with formula flour or water also gave fully functional AP in bread doughs as evidenced by complete shortening replacement at 0.38% AP (based on flour weight) and by the absence of dark specks on the crust of bread. Compared to a mixture of 0.38% AP and 3% shortening or a mixture of 0.5% monodiglycerides and 3% shortening, AP alone at 0.38% in bread gave softer crumb after 1 to 5 days storage at 25°C. Sodium stearoyl 2-lactylate (SSL) at 0.38% gave the same softening effect as AP. In no-shortening loaves, 0.38% AP gave better grain than 0.75% L-ascorbyl 6-octanoate or 0.50% L-ascorbyl 6-dodecanoate.     

Sequence dependent set-up times and job sequencing

On many machine tools the set-up times are sequence dependent; that is, the time to set-up for the new part is dependent upon the part for -which the machine is currently set-up. In scheduling lots on the machine, the set-up time is often a significant component of the total time required to complete each lot. Set-up times are frequently not available to the production scheduler, and when they are, they frequently are only averages which conceal the sequence dependency of the set-up times. In this paper, we first develop a procedure that classifies set-up operations and predicts the set-up times and we then develop a method for sequencing the jobs so as to minimize the total set-up time. An example using real world data is used to illustrate these procedures     

Caractérisation de formations végétales mediterranéennes à partir de données ‘Thematic Mapper’ Une étude de cas en Andalousie (Espagne)

Abstract

The study is focused on the characterization of vegetation formations in a Mediterranean area (943 km²) located in southern Spain: herbaceous canopies (rangelands), shrubby vegetation (‘matorral’) and complex woody/herbaceous formations (‘dehesa’). Vegetation formations (physiognomical units) have been characterized by their spectral responses in the six reflective TM channels and by vegetation indices. From the ratio index TM4/TM3 there has been derived a map displaying seven classes (water, bare soil and five biomass levels reflecting the hierarchy of vegetation formations). Channels TM3, TM4 and TM5 have been considered for a supervised classification into nine land-cover categories (seven vegetation formations, bare soil and water). The proportion of correct classification of vegetation formations is about 78 per cent when considering test areas. Classification made from three principal components gives similar results.     

Instant infusion pasteurisation of bovine milk. II. Effects on indigenous milk enzymes activity and whey protein denaturation

Direct heat treatment of two milk types, skimmed and nonstandardised full‐fat, was performed by instant steam infusion and compared with indirect heating. Infusion conditions were temperatures of 72–120°C combined with holding times of 100–700 ms, and indirect heat conditions were 72°C/15 s and 85°C/30 s. The activity of indigenous enzymes such as alkaline phosphatase, lactoperoxidase, xanthine oxidase and γ‐glutamyl transpeptidase was evaluated. Infusion temperature was the main determinant of inactivation. Whey protein denaturation represented by β‐lactoglobulin increased significantly with infusion temperature. The nonstandardised milk had a higher denaturation rate than skimmed milk. The effect of instant infusion on pH and milk fat globule size in relation to whey protein denaturation and association is discussed.     

Effect of Temperature on Collagen Extractability and Kramer Shear Force of Restructured Beef

Collagen extractability and Kramer shear force were measured for raw and heated restructured beef products made with trimmed (epimysium removed) and untrimmed clods (triceps brachii, infraspinatus, and supraspinatus). Collagen extractability was significantly (p < 0.001) higher for untrimmed samples heated at 50°C than for trimmed samples. Kramer shear forces were significantly higher (p < 0.01) for untrimmed than trimmed when raw or heated at 35°C, 45°C, WC, and 55°C. Collagen extractabilities showed no distinct changes with temperature for trimmed samples. Collagen extractability of untrimmed samples increased then decreased as heating temperature increased. Kramer shear forces decreased between 55°C and 60°C for both trimmed and untrimmed samples.     

BIRTH ORDER AND SCHOOL-RELATED BEHAVIOR: A HEURISTIC REVIEW.

EVIDENCE INDICATES A FORMIDABLE LINK BETWEEN BIRTH ORDER AND COLLEGE MATRICULATION. OVERWHELMING EVIDENCE SHOWS THAT 1ST-BORNS OF BOTH SEXES ATTEND COLLEGE IN GREATER NUMBERS THAN LATER-BORN PEERS. WHILE EXPLANATIONS OF THIS PHENOMENON ARE TENUOUS, SUBSTANTIAL EVIDENCE EXISTS INDICATING THAT EARLY PERSONALITY FACTORS FAVORING 1ST-BORNS ARE SUBSTANTIATED AND EXTENDED WHILE IN SCHOOL. 1ST-BORNS MORE FREQUENTLY: (1) MEET TEACHERS' EXPECTATIONS, (2) SHOW MORE SUSCEPTIBILITY TO SOCIAL PRESSURE, AND (3) EXHIBIT GREATER INFORMATION-SEEKING BEHAVIOR AND SEEM MORE SENSITIVE TO TENSION-PRODUCING SITUATIONS. THESE BEHAVIORS MAY STRENGTHEN ACHIEVEMENT MOTIVATION AND ENHANCE ACADEMIC PERFORMANCE. (36 REF.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)