New high-silicon zeolites of the TsVN series

Translated from Khimiya i Tekhnoloyiya Topliv i Masel, No. 3, pp. 3–5, March, 1989.     

The application of multivariat mathematical-statistical methods to the solution of problems in nutrition theory,nutritional economics and food technology Part 4. Optimization with n ≥ 2 effect variables

The milling industry faces the task of saving energy without impairing the quantity and quality of the products. By applying experimental plans for the optimization of several effect variables, approximations (compromise solutions) between the cause variables (conditioning parameters) and the effect variables (quantity and quality parameters) are sought, which satisfy the aims laid down.     

The development of a stress analysis code for nuclear graphite components in gas-cooled reactors

Most of the UK nuclear power reactors are gas-cooled and graphite moderated. As well as acting as a moderator the graphite also acts as a structural component providing channels for the coolant gas and control rods. For this reason the structural integrity assessments of nuclear graphite components is an essential element of reactor design. In order to perform graphite component stress analysis, the definition of the constitutive equation relating stress and strain for irradiated graphite is required. Apart from the usual elastic and thermal strains, irradiated graphite components are subject to additional strains due to fast neutron irradiation and radiolytic oxidation. In this paper a material model for nuclear graphite is presented along with an example of a stress analysis of a nuclear graphite moderator brick subject to both fast neutron irradiation and radiolytic oxidation.     

Leaching of zinc sulfide concentrate from the ganesh-himal deposit of nepal

The leaching of zinc concentrate obtained from the zinc ore located in the Ganesh-Himal region of Nepal has been carried out in the presence of ammonium persulfate (APS) as an oxidant. Leaching variables such as time, temperature, acid, and oxidant concentration, E _h , and particle size of sphalerite concentrate were studied to optimize the condition and to understand the mechanism of the reaction. The zinc extraction increased up to a temperature of 333 K and a further rise in the temperature to 343 K resulted in lowering of metal extraction. A decrease in particle size and increase in oxidant concentration enhanced the dissolution rate of zinc. The leaching data best fitted to the mixed controlled kinetic model. An activation energy of 43 kJ/mol was obtained for the dissolution of zinc in the temperature range 303 to 333 K with APS. The leaching mechanism was further established by characterizing the original concentrate and the leach residue by X-ray diffraction (XRD) phase identification and scanning electron microscopy (SEM) studies.     

Stormwater reuse: designing biofiltration systems for reliable treatment.

Stormwater reuse is increasing in popularity as a technique for overcoming water shortages in urban Australia. However, technology for the reliable treatment of stormwater for reuse is still not fully developed. This paper presents the first steps in refining biofilters for stormwater reuse. Six different filter media were selected, to target specific stormwater pollutants, as well as support plant growth. They were tested in the laboratory, where the filters were dosed three times per week with semi-synthetic stormwater for five weeks. Pollutant removal performance was monitored, and revealed that all soil-based filters performed similarly (while sand filters behaved somewhat differently). All filters removed more than 80% of solids and greater than 90% of lead, copper, and zinc. Three filter types were able to remove some phosphorus (particularly in the top 30 cm of the media). Apart from sand, all filter media were net producers of nitrogen, leading to an important conclusion that non-vegetated, soil-based filters are not suitable for targeting nutrients. However, since heavy metals are the primary pollutant of concern with respect to stormwater reuse for irrigation (the most popular end-use), it was concluded that biofilters may be promising technologies for treatment of stormwater for reuse.     

Off flavours in large waterbodies: physics, chemistry and biology in synchrony.

The Laurentian Great Lakes of North America are a drinking water source for millions of Canadian and US consumers. These waterbodies have undergone extensive change over the past century as a result of widespread degradation and remediation. Many of the Lakes are prone to taste and odour (T&O), and although these outbreaks have been poorly monitored, evidence suggests that they are increasing in frequency. Tracing and controlling T&O in such large systems presents a challenging task, due to their physical size and complexity. This paper presents an overview of recent investigative and management approaches to T&O in Lake Ontario and its outflow, the St. Lawrence River. We have identified three distinct patterns of T&O in these source-waters, caused by geosmin and 2-methylisoborneol and differing in their planktonic and benthic sources, and temporal and spatial dynamics. Each pattern has required a different approach by scientists and management, in partnership with the water industry. We have shown these T&O outbreaks are caused and moderated by physical, chemical and biological mechanisms over a spectrum of spatial and temporal scales. Canadian municipalities affected by these outbreaks have been key to the investigation of the links between T&O and ecosystem processes with the aim to develop more proactive water treatment and long-term management.     

Computer-aided design: a case of strategy in implementing a newtechnology

In this case study the introduction of computer-aided design (CAD) in an engineering company was analyzed. The process of change as well as repercussions of the new technology on work organization and communication patterns within the company were studied. The designers has received the new technology favorably and were even impatient about the pace of change. As the development of the system was limited to a small group close to the design management, the introduction had less than desirable effects on the work situation of the designers and on the cooperation with other functions that was envisaged in the planned CAD/CAM step. The study confirms that CAD, as such, will have little effect on a bureaucratic organization unless such a change is included as an explicit objective. For a full utilization of any new technology a joint forum for outlining a strategy is needed