SHORT COMMUNICATION: EVOLUTION OF BACTERIAL COMMUNITY IN A PYRITIC REFRACTORY GOLD ORE COLUMN LEACHING ENVIRONMENT

This short communication highlights important biological features of a pyritic refractory gold ore heap-leaching environment. Acidithiobacillus ferrooxidans and Leptospirillum ferrooxidans were to be two of only three bacterial species detected on the ore surfaces at ambient temperature. Sulfobacillus was not originally introduced in the inoculum, but was later detected in the column. Only organisms of the Leptospirillum genus were present in the ferric sulfate leaching solution. Ignoring that the ore hosted approximately 500 times more microorganisms than the solution can greatly underestimate the oxidizing potential. One or more of these microorganisms oxidized ferrous ions, leading to a rise in the solution potential. They also oxidized elemental sulfur, resulting in a higher sulfate yield than measured in sterile medium.     

NATIONAL SECURITY/EMERGENCY PREPAREDNESS AND DISASTER RECOVERY COMMUNICATIONS VIA ACTS

During the period from early 1993 to 1994, the U.S. National Communication System (NCS), a government agency, sponsored the development and execution of several fixed and mobile experiments using the advanced communications technology satellite (ACTS). The purpose of these experiments was to evaluate the feasibility of integrating an ACTS-like communications system into national security/emergency preparedness (NS/EP) operational scenarios. These experiments focused on clear and secure voice communications in both the fixed and mobile environment. For the mobile experiments, the focus was on the performance of both clear and secure voice in the land-mobile satellite communications channel. For the fixed experiments, the focus was on the use of a T1 terminal for restoration of communication services in the event of a disaster and for remote user communications. The results of these experiments are described in this paper.     

An implicit enumeration approach to tolerance allocation in sequential tolerance control

The accuracy and precision of a manufactured dimension is largely dependent on the accuracy and precision of the technological processes selected for its execution. It is not unusual to have available several competing technological processes for execution of each manufacturing operation specified in a process plan, where it is generally assumed that as the precision of the technological process improves, the associated cost and yield of the operation increase. This paper presents an implicit enumeration approach to the selection of an optimum subset of technological processes required to execute a process plan under a. sequential (or adaptive) tolerance control strategy.     

Knudsen Effusion Study of the Vaporization of CdO(s)

Knudsen effusion studies were conducted on CdO(s) in fused-SiO₂ Knudsen cells from 889 to 1110 K. The orifice size was varied; the largest cell orifice yielded a calculated pressure significantly lower than could be accounted for by experimental error. Average-slope- and average-free-energy-function-based values of Δ H ^c₂₉₈ were 86.9 ± 1.1 and 88.8 ± 0.5 kcal/mol, respectively. The data from the present work were combined with those of previous investigators using a method discussed by McCreary and Thorn; a Δ H ^c₂₉₈ of 88.2 ± 0.2 kcal/mol was obtained. Using this combined value for Δ H ^c₂₉₈ and ΔS^c₂₉₈= 51.40 ± 0.1 eu (obtained from the literature), the equilibrium constant for the reaction CdO(s)= Cd(g)+ 1/2 O₂(g) at 900 to 1380 K was calculated to be log K = 10.6-18,800(I/T).     

Modelling the effects of peanut flour, feed moisture content, and extrusion temperature on physical properties of an extruded snack product

A mixture experimental design was used to evaluate the combined effects of non-fermented (PDPF) and fermented (F-PDPF) peanut flours, added feed moisture content, and extrusion temperature on physical properties of extruded cornstarch-peanut flour-based snacks. Moisture content, expansion ratio, bulk density, modified Kramer compression-shear force and colour of extrudates were significantly affected by the amount of PDPF and F-PDPF in the formulation. Oil absorption by extrudates was only influenced by the type of peanut flour. Within the range of (per 1-kg batch) 0.30–0.34 g g⁻¹ added water, 0.16–0.20 g g⁻¹ PDPF and/or F-PDPF, and extrusion temperatures of 125 to 150°C, extrudates with a wide range of functional characteristics can be produced.     

Asymptotic tracking by a reinforcement learning-based adaptive critic controller

Adaptive critic (AC) based controllers are typically discrete and/or yield a uniformly ultimately bounded stability result because of the presence of disturbances and unknown approximation errors. A continuous-time AC controller is developed that yields asymptotic tracking of a class of uncertain nonlinear systems with bounded disturbances. The proposed AC-based controller consists of two neural networks (NNs) – an action NN, also called the actor, which approximates the plant dynamics and generates appropriate control actions; and a critic NN, which evaluates the performance of the actor based on some performance index. The reinforcement signal from the critic is used to develop a composite weight tuning law for the action NN based on Lyapunov stability analysis. A recently developed robust feedback technique, robust integral of the sign of the error (RISE), is used in conjunction with the feedforward action neural network to yield a semiglobal asymptotic result. Experimental results are provided that illustrate the performance of the developed controller.     

MINE VENTILATION EXPERT SYSTEM

A growing trend in the area of artificial intelligence is the development of software that simulates the decision-making process of human experts. The purpose of this paper is to advance the use of available tools from the area of artificial intelligence, and in particular expert systems, into the field of mine ventilation management. The authors have developed an expert system (i.e., a smart manager) that controls the operation of a mine ventilation network. The expert system is rule based and hence can be (independently) enhanced in an incremental fashion. It serves as a smart interface between the monitoring and control components of a mine ventilation system.     

Improving water use efficiency in grapevines: potential physiological targets for biotechnological improvement

Improving water use efficiency (WUE) in grapevines is essential for vineyard sustainability under the increasing aridity induced by global climate change. WUE reflects the ratio between the carbon assimilated by photosynthesis and the water lost in transpiration. Maintaining stomata partially closed by regulated deficit irrigation or partial root drying represents an opportunity to increase WUE, although at the expense of decreased photosynthesis and, potentially, decreased yield. It would be even better to achieve increases in WUE by improving photosynthesis without increasing water loses. Although this is not yet possible, it could potentially be achieved by genetic engineering. This review presents current knowledge and relevant results that aim to improve WUE in grapevines by biotechnology and genetic engineering. The expected benefits of these manipulations on WUE of grapevines under water stress conditions are modelled. There are two main possible approaches to achieve this goal: (i) to improve CO₂ diffusion to the sites of carboxylation without increasing stomatal conductance; and (ii) to improve the carboxylation efficiency of Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco). The first goal could be attained by increasing mesophyll conductance to CO₂, which partly depends on aquaporins. The second approach could be achieved by replacing Rubisco from grapevine with Rubiscos from other C₃ species with higher specificity for CO₂. In summary, the physiological bases and future prospects for improving grape yield and WUE under drought are established.     

轻量级——莲花Lotus Eagle

英国莲花跑车可以说是当今最有个性的车型之一，高强度粘合工艺造就了其超轻量化的车身，越的性能使其成为很多车迷的猎物。