A specific effect of alkali-metal iodides and thiocyanates on the viscosity of solutions of poly(methacrylic acid) in methanol

The solution properties of poly(methacrylic acid) (PMA) in methanol are specifically affected by thiocyanates and iodides of alkali metals. The relative decrease in the reduced specific viscosity of PMA in dilute methanolic solutions due to KSCN depends only on the ratio of concentrations of polymer and salt, and is independent of temperature and polymer molecular weight. With copolymers of methacrylic acid and 2-hydroxyethyl methacrylate, the effect is weaker.     

A Temperature Control System for Small Biological Preparations, Displaying Relatively Fast Heating and Cooling Capability

An apparatus is described with which it is possible to warm and cool the main duct of rabbit submaxillary gland in 10cc Ringer solution between 0°C and 50°C. The apparatus can be used for any small biological preparations such as muscles, nerves, etc. The heating and cooling is performed by a peltier element together with its control unit. Temperature is measured with a Cu-Const. thermocouple-with the reference placed in melting ice. The absolute accuracy of the temperature is ±0.5°C but reproducibility is within 0.10C. Speed of warming up for a large temperature change (AT) is 0.8°C/s. Cooling is-stower, i.e., 0.4°C/s. For AT 5°C the speed of warming up is about 0.60°C/s and the cooling rate in this case varies between 0.5°C/s and 0.16°C/s depending upon starting temperature. Full details are given about the construction of the control unit and the perfusion chamber in which the main duct is mounted. Some modifications are discussed with which it is also possible to use the system for flat biological preparations. The use of the apparatus as a programmable temperature system or as a temperature function generator is also discussed.     

Kinetics and equilibria of the hydration of propene over a strong acid ion exchange resin as catalyst

The kinetics and equilibria of the direct hydration of propene over a strong acid ion exchange resin (C8P ex AKZO) were studied. The experiments were c     

Supercritical carbon dioxide extraction ofDimorphotheca pluvialis oil seeds

The possibility of extraction ofDimorphotheca oil with supercritical carbon dioxide is demonstrated in this article. Before extraction, the seeds have to be pretreated to improve extraction yield. Experiments showed that the best pretreatment procedure forDimorphotheca was heating the seeds under reduced pressure to 100°C for 60 min, followed by flaking or milling. To give an impression about the efficiency of the supercritical extraction, a mathematical model has been developed to estimate the overall mass transfer coefficient (A _p K). Also, an empirical relation betweenA _p K and the interstitial velocity has been found. The physical properties of the supercriticalDimorphotheca oil are in good agreement with those of conventionally extracted oil, except for a lower phospholipid content. It is expected that further refining of supercriticalDimorphotheca oil will be marginal.     

Fabrication and properties of point structures formed on <Emphasis Type="Italic">n</Emphasis>-InSe single crystals

Point structures based on InSe single crystals were obtained by the method of electric discharge. The steady-state current-voltage characteristics and the photosensitivity of the structures (point contact)/n-InSe were studied. Rectification was found and the first spectra of photosensitivity of the structures obtained by electric discharge were measured. The broadband character and excitonic feature of the photosensitivity spectra of the structures (point contact)/n-InSe were observed and discussed. It is established that the point structures can be used as broadband photoconverters of optical radiation.     

Behaviour of coal mineral matter in sintering and slagging of ash during the gasification process

The mineral matter in typical feed coals used in South African gasification processes and the ash derived from gasifying such coals have been investigated using a variety of mineralogical, chemical and electron microscope techniques. The mineral matter in the feed coals consists mainly of kaolinite, with minor proportions of quartz, illite, dolomite, calcite and pyrite plus traces of rutile and phosphate minerals. The calcite and dolomite occur in veins within the vitrinite macerals, and are concentrated in the floats fraction after density separation. Some Ca and Ti also appear to be present as inorganic elements associated with the organic matter.Electron microscope studies show that the gasification ash is typically made up of partly altered fragments of non-coal rock, bonded together by a slag-like material containing anorthite and mullite crystals and iron oxide particles, with interstitial vesicular glass of calcic to iron-rich composition. Ash formation and characteristics thus appear to be controlled by reactions at the particle scale, allowing the different types of particles within the feed coal to interact with each other in a manner controlled mainly by the modes of mineral occurrence. Integration of such techniques provides an improved basis for evaluating ash-forming processes, based on quantitative phase identification, bulk and particle chemistry, and the geometric forms in which the different phases occur.     

Annual planning of harvesting resources in the forest industry

A cost‐efficient use of harvesting resources is important in the forest industry. The main planning is carried out in an annual resource plan that is continuously revised. The harvesting operations are divided into harvesting and forwarding. The harvesting operation fells trees and puts them in piles in the harvest areas. The forwarding operation collects piles and moves them to storage locations adjacent to forest roads. These operations are conducted by machines (harvesters, forwarders and harwarders), and these are operated by crews living in cities/villages that are within some maximum distance from the harvest areas. Machines, harvest teams and harvest areas have different characteristics and properties and it is difficult to find the best possible match throughout the year. The aim of the planning is to find an annual plan with the lowest possible cost. The total cost is based on three parts: production cost, traveling cost and moving cost. The production cost is the cost for the harvesting and forwarding. The traveling cost is the cost for driving back and forwards (daily) from the home base to the harvest area and the moving cost is associated with moving the machines and equipment between harvest areas. The Forest Research Institute of Sweden (Skogforsk), together with a number of Swedish forest companies, has developed a decision support platform for the planning. One important element of this platform is that it should find high‐quality plans within short computational times. One central element is an optimization model that integrates the assignment of machines to harvest areas and schedules the harvest areas during the year for each machine. The problem is complex and we propose a two‐phase solution method where, first, we solve the assignment problem and, second, the scheduling. In order to be able to control the scheduling in phase 1 as well, we have introduced an extra cost component that controls the geographical distribution of harvest areas for each machine in phase 1. We have tested the solution approach on a case study from one of the larger Swedish forest companies. This case study involves 46 machines and 968 harvest areas representing a log volume of 1.33 million cubic meters. We describe some numerical results and experience from the development and tests.     

Jammed architectural structures: towards large-scale reversible construction

This paper takes a first step in characterizing a novel field of research—jammed architectural structures—where load-bearing architectural structures are automatically aggregated from bulk material. Initiated by the group of Gramazio Kohler Research at ETH Zürich and the Self-Assembly Lab at Massachusetts Institute of Technology, this digital fabrication approach fosters a combination of cutting-edge robotic fabrication technology and low-grade building material, shifting the focus from precise assembly of known parts towards controlled aggregation of granular material such as gravel or rocks. Since the structures in this process are produced without additional formwork, are fully reversible, and are produced from local or recycled materials, this pursuit offers a radical new approach to sustainable, economical and structurally sound building construction. The resulting morphologies allow for a convergence of novel aesthetic and structural capabilities, enabling a locally differentiated aggregation of material under digital guidance, and featuring high geometrical flexibility and minimal material waste. This paper considers (1) fundamental research parameters such as design computation and fabrication methods, (2) first results of physical experimentation, and (3) the architectural implications of this research for a unified, material-driven digital design and fabrication process. Full-scale experimentation demonstrates that it is possible to erect building-sized structures that are larger than the work-envelope of the digital fabrication setup.     

Fumonisin-Producing Fusarium from Maize Grains in Tretep,Indonesia

Fusarium species commonly occur in maize are fungal pathogen which produce mycotoxins, such as fumonisin, trichothecene and zearalenone. In this study, Fusarium species were isolated from maize kernel from Tretep, maize producer region and were identified based on microscopic- and macroscopic characters as well as molecular characters using PCR assays and the partial sequence of TEF 1-α gene （Translation Elongation Factor 1-α. The fumonisin-producing ability of these Fusarium was determined by growing them in corn medium and analyzed their fumonisin by ELISA （enzyme-linked immuno assay）. Among 9 isolates, three of them were identified as Fusarium verticillioides, two as Fusarium temperatum, two as Fusarium globosum, one as Fusarium proliJeratum and one as Fusarium subglutinans. Fusarium temperatum is similar morphologically to F. subglutinans, however, both of their differences can be found by molecular analysis. Fumonisin-producing abilities of Fusarium were determined in concentrations 20.51 pg/g-1,109.74 pg/g medium with the highest producer was identified as F. globosum.