Investigation of heat and mass transfer in a gauze‐type structured packing liquid desiccant dehumidifier

In this experimental investigation, a packed bed column suitable for 5‐ton hybrid cooling system has been designed to study the absorption of water vapour from moist air by contact with aqueous solutions of calcium chloride. The packing material used in the study was two elements of the BXPEP structured packing and the height of the each element was 17 cm. This packed bed dehumidifier handles desiccant flow rates from 10 to 32 l/min. This paper presents results from a detailed experimental investigation of the heat and mass transfer between a liquid desiccant (calcium chloride) and air in a gauze‐type structured packing dehumidifier. The effects of different independent variables such as air inlet absolute humidity, desiccant inlet temperature, flow rate and its concentration on the performance of the dehumidifier have been investigated. Copyright © 2002 John Wiley & Sons, Ltd.     

Volumetric Mass Transfer Coefficient in non‐Newtonian Fluids in Spout Fluid Beds

The volumetric liquid‐phase mass transfer coefficient, k_La, was determined by absorption of oxygen in air using six different carboxy‐methyl cellulose (CMC) solutions with different rheological values in three phase spout‐fluid beds operated continuously with respect to both gas and liquid. Three cylindrical columns of 7.4 cm, 11.4 cm, and 14.4 cm diameters were used. Gas velocity was varied between 0.00154–0.00563 m/s, liquid velocity between 0.0116–0.0387 m/s, surface tension between 0.00416–0.0189 N/m, static bed height between 6.0–10.8 cm, and spherical glass particles of 1.75 mm diameter were used as packing material. A single nozzle sparger of 1.0 cm diameter was used in the spouting line. The volumetric mass transfer coefficient was found to increase with gas velocity, liquid velocity, and static bed height and to decrease with the increase of the effective liquid viscosity of the CMC solution. A dimensionless correlation was developed and compared with those listed in the literature.     

Investigation of the specific interfacial area of a palm oil–water system

Oil–water dispersions have many important applications in the chemical and oleochemical industries. A measure of the specific interfacial area of the dispersed phase provides a direct indication of the quality of the dispersion. In this study, the specific interfacial area for the palm oil–water system was determined using a microscopic technique. The effects of oil volume fraction, agitation speed and temperature on the specific interfacial area have been determined experimentally and an empirical correlation to predict the total specific interfacial area under different operating conditions is proposed. This correlation can be used in the design of reaction and non‐reaction systems using palm oil–water dispersions. Copyright © 2004 Society of Chemical Industry     

Measurement of large gasndashliquid interfacial areas

The light attenuation technique has been modified to expand the range of its applicability up to AL values of 460. This has been accomplished through the use of a laser as the source of monochromatic collimated light, and a very sensitive low-bias picoammeter. The data obtained using the photographic technique were found to agree reasonably well with those from light attenuation.     

Evaluation of dams as a recharge method

Dams are used for recharge purposes in many parts of Saudi Arabia. In spite of the importance of such a method, no detailed study exists on its performance. As a part of a comprehensive research project dealing with all aspects of dams as a recharge tool in the central region of the country, data on reservoirs’ water levels, meteorological parameters and observation wells were collected at two recharge dam sites. These data were used in a water budget approach to estimate efficiency. Contrary to the established belief that this method of recharge is poor, results show that between 82% and 94.5% of water stored in the two reservoirs was taken into the soil.     

Physics students' conceptions of energy and technological development in energy

There has been strong international interest in students' understanding concerning phenomenon taught in physics. Many studies have been conducted to find out students' conceptions in various concepts in physics. This study was designed to find out students' conceptions of the relationship of energy use and technological development in energy. It was conducted by administering a questionnaire to 133 first year physics students at a university. A questionnaire entitled “Questionnaire On Energy And Technological Development” was used to collect data for this study. The results were analyzed to identify students' conceptions on energy use and technological development in energy. Finally, implications on teaching of energy is discussed in this paper.     

Liquid dispersion in static in-line mixers

Liquid/liquid dispersion in static mixers has been investigated using Lightnin “In-liner” mixing elements. The average drop size was found to decrease with increasing residence time, gradually approaching an equilibrium size whose magnitude agrees reasonably well with Kolmogoroff's theory for drop rupture in turbulent flows. The efficiency at which mechanical energy is utilized in the generation of new interfacial area was evaluated as a function of design and operating conditions and was found to be highest when the final drop size is much larger than the achievable equilibrium value.     

A method for determining the settling behavior of dense suspensions

An accelerated method for evaluating the compaction behavior of dense suspensions is presented, in which centrifugal force is used to enhance settling rates and a highly-compensated compound pendulum is used to detect the resultant small shifts in centre of gravity. The results obtained by following the temporal variation in suspension characteristics indicate that a Richardson and Zaki type of equation can describe the subsidence of very concentrated suspensions. The exponent n, and the ultimate sediment compaction density were found to be strongly influenced by small changes in the physicochemical characteristics of the suspended solids.     

一种新颖的超大点阵分束实现方法

首次提出了一种实现超大卢、阵光束分束的新方法，它是利用位相迭加原理和ＶＬＳＩ技术将光栅分束器和位相型菲涅耳微透镜列阵集成为一体，构成了一种新型的光束分束列阵器件—一菲涅耳计算机源生全息分来器（ＣＧＦＢＳ），以实现１２８×１２８，甚至更高卢、阵数的光点分束。     

Scientific-Technical Support for Innovation at Companies, Research Institutes, and Other Organizations in the Metallurgical Sector

A recent seminar explored new innovations in metallurgical technology and provided a forum for discussing how companies and research organizations manage and plan activities in this area. Two of the specific cases examined were the work done by the Moscow Institute of Steel and Alloys to find new ways to develop the Udokan copper deposit and the efforts of the institute Stal’proekt to provide engineering-technical support to companies interested in modernizing their furnaces. Among the other topics covered were technical consulting on the use of technogenic materials, the recycling of such materials by the Romelt process, an energy-saving method of producing cast iron and ferroalloys in a new type of furnace — an oxygen reactor — and the development and introduction of automated production units in metallurgy. Reports were also given on new high-strength corrosion-resistant steels, the possible use of new protective coatings on steel plates and tubes, and aspects of micro-metallurgy.Translated from Metallurg, No. 1, pp. 45–49, January, 2005.