Experimental observations of chemical and thermal gradients in an experimental BOF

The objective of this investigation was to determine the chemical and thermal gradients during steel making in a pilot size basic oxygen furnace. It was postulated that if these gradients could be determined under different conditions, conflicting theories of operation could be tested and optimum operating conditions would be indicated. New sample probe techniques were developed in which the probes are inserted through the side of the vessel to desired locations. Shortly after reaching the desired locations, the tip of an evacuated tube inside the probe opens and delivers metal to the other end of the probe outside the vessel. Temperatures were determined throughout the bath by specially reinforced but sensitive thermocouple probes. Important differences in both chemical and thermal gradients were found. The gradients were greatest with shallow penetration of the jet-for example after 3 min in a heat with about 1 in. penetration, the P content varied from 0.05 to 0.17 pct, silicon from 0.05 to 0.20 pct and the temperature from 2500° to 2900° F. These variations were found in a bath only 6 in. deep and 15 in. diam. By contrast, with deeper jet penetration to the center of the bath, the gradients were greatly reduced. Regardless of the operating conditions employed, the data indicate a metal circulation pattern which is upward from the jet cavity and radially outward at the surface. Even more important, by inserting a spray collector above the bath, it was found that with hard blowing the jet pumps out a volume of droplets during a heat which is equal to the bath volume. These droplets are rapidly oxidized,e.g. from 3.6 to 0.4 pct C, in their flight above the bath and are an important consideration in refining.     

Pavlovian appetitive contingencies and approach versus withdrawal to conditioned stimuli in pigeons.

Investigated the directed skeletal movements of 21 female White Carneaux pigeons toward signals of food or no food in 3 experiments. Ss approached and pecked an illuminated key that was positively correlated with food delivery, and positioned themselves relatively far from an illuminated key that was negatively correlated with food delivery. Key illuminations alone, random presentations of key illuminations and food, and backward pairings of key illuminations and food did not produce keypecking or consistent approach-withdrawal. Therefore, directed skeletal behavior-often believed to be conditioned and maintained primarily or exclusively by operant procedures-also emerges on Pavlovian procedures. Several kinds of alternative explanations (e.g., conditioned reinforcement effects, and stimulus substitution) for these phenomena are considered, and some potential implications for operant discrimination learning are briefly explored. (17 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Securing the Operating System: Does lesser-known mean less at risk? Is the OS an example of security though obscurity?

It is no secret that Microsoft Windows NT is the hacker’s favourite Operating System (OS). According to defacement-tracking site Attrition.org, (www.Attrition.org) Windows NT received 54.41% of all recorded OS attacks between August 1999 and April 2001. In stark contrast, some of the lesser-known Operating Systems made up for as little as 0.1% of all OS attacks. However, despite the huge difference in the quantity of attacks, companies that employ the lesser-known systems may be at greater risk…     

Synthesis and characterization of citric acid-based pH-sensitive biopolymeric hydrogels

Biocompatible hydrogels based on citric acid (CA) with varying glycol unit, viz., ethylene glycol (EG), diethylene glycol and triethylene glycol were prepared along with acrylic acid. The formations of various hydrogels were confirmed using spectral techniques such as FT-IR and ¹H NMR. Thermal stability (thermogravimetric analysis, DTA and differential scanning calorimetry) and morphology (SEM) of the synthesized hydrogels were investigated. Swelling studies of hydrogels at various pH values ranging from 4.0 to 10.0 were also investigated. The results of swelling studies show that the percentage of swelling is comparatively higher at higher pH than lower pH. Swelling equilibrium for various hydrogels was also found. Increased composition of CA in hydrogels at different pH values of 4.0, 6.0, 7.4, 8.0 and 10.0 enhanced the swelling equilibrium.     

Mixed‐cation LiCa‐LSX zeolite with minimum lithium for air separation

The aim of this work was to reduce/minimize Li in Li‐LSX by replacing the 70% Li⁺ cations in Li‐LSX that are bonded to the interior or inaccessible sites which are not used for adsorption. Thus, mixed‐cation LiCa‐LSX containing minimum lithium were prepared by exchanging small fractions of Li⁺ into Ca‐LSX, followed by dehydration under mild conditions to avoid migration/equilibration of Li cations. Comparisons of adsorption isotherms of N₂/O₂ and heats of adsorption for the LiCa‐LSX samples with that for pure‐cation Li‐LSX and Ca‐LSX provided strong evidence that significant amounts of these Li cations indeed remained on the exposed sites (SIII). The mixed‐cation LiCa‐LSX samples were compared against the pure‐cation Ca‐LSX and Li‐LSX based on their performance for oxygen production by PSA, via model simulation. The results showed that the mixed‐cation LiCa‐LSX samples yielded significantly higher O₂ product productivities at the same product purity and recovery than their pure‐cation precursor (Ca‐LSX). © 2017 American Institute of Chemical Engineers AIChE J, 64: 406–415, 2018     

Classification of soil‐ and bedrock‐dominated landslides in British Columbia using segmentation of satellite imagery and DEM data

Landsat Enhanced Thematic Mapper Plus (ETM+) and digital elevation model (DEM) data were used in a segmentation and classification procedure to classify slide scars in the northern Cascade Mountains of British Columbia, Canada. The area was stratified into features that were likely candidates for landsliding and those that were not; shape criteria were applied that were used to identify objects as slides; and finally, rules based on shape, texture and neighbouring features were used to separate soil‐dominated slides from bedrock‐dominated slides, an important distinction in mass movement inventories and for applied and theoretical studies. Approximately 65% classification accuracy was obtained. Slopes experiencing multiple failures, which can create less distinct features on the ground, may have contributed to some of the error in classification.