Quality Function Deployment (QFD) and TRIZ in Briquette Cookstove Design and Simulation

Poor cookstove design can harm the user's health and environment. This research aims to obtain an efficient cookstove design, environmentally friendly and operated easily. The cookstove design process using a combination of QFD and TRIZ. QFD able to capture customer needs through a questionnaire and interview. The data collected then processed to build a House of Quality (HoQ), one of the tools in QFD. QFD results in the design parameter of the briquette cookstove, which is incorporated in the concept design. The TRIZ method is utilized to understand the problem that might occur in the concept design and focus on solving the root causes. The next step is a detailed design where the dimensions, combustion chamber capacity, and supporting features are explained. The combination of QFD and TRIZ result in a briquette cookstove concept design which is easy to clean and operate. The combustion system is Top-lit Up-Draft (TLUD). The burning chamber has two air inlets, namely primary and secondary. The primary air inlet supplies the air from the bottom of the burning chamber, partially burns the briquette, and produces flue gas. The secondary air inlet is in the shape of an oval to supply air in the burning chamber's upper part to burn the flue gas completely. A complete combustion process will increase combustion efficiency and reduce emissions. A computational simulation shows the velocity distribution inside the burning chamber.

Assessment of the efficiency of non-metallic inclusions removal through the use of centrifugal force at different stages of steel production

Methods for the removal of non-metallic inclusions from steel at various stages of its production are considered: in a teeming ladle, a tundish and a CCM mold. It is proposed to classify methods of non-metallic inclusions removal into two groups: mechanical (inert gas blowing, application of electromagnetic stirrers, etc.) and physical and chemical (modification of non-metallic inclusions, slag treatment, rational deoxidation modes). Particular attention is paid to methods aimed at creating a vortex in the metal, inside which non-metallic inclusions are transported to its axis. The aim of the work is to determine the efficiency of use centrifugal forces to remove non-metallic inclusions at different stages of steel production. To assess the centrifugal force effectiveness, it has been analyzed the transfer time of non-metallic inclusions of various sizes to the vortex axis in the teeming ladle of 50 tons capacity, a rotary chamber of tundish (chamber capacity is 2.0 tons) and the CCM mold of 160 mm in diameter. For typical angular velocities being observed during electromagnetic stirring, the values of the metal inertia moment and the kinetic energy of its rotational motion have been calculated. According to the calculations, the smallest transfer time of inclusions is achieved in the teeming ladle. However, vortex creation in it requires a significant energy. The use of centrifugal force in the mold, although it does not require such a high energy, is also not efficient enough due to the low angular velocity of the vortex, limited by a risk of violating the crust formation in the mold. The possibility of using the kinetic energy of the jet flowing from the teeming ladle to the rotary chamber of the tundish has been assessed.

Design, Fabrication and Performance Evaluation of a Domestic Gas Oven

This study reports on the design, construction and performance evaluation of a domestic gas oven. The oven was designed and was fabricated with an outer dimension of 860 mm length × 660 mm width × 1150 mm height made up of mild steel and the inner dimension of 759 mm length × 559 mm width × 835 mm height made up of mild steel and fiber glass of 40 mm thickness was used as an insulator to reduce cost to a minimal level. The aim of this research work is to improve on the already existing gas baking oven through the incorporation of a vent/chimney for removal of humid air and roller (wheels) for easy movement. Cooking gas is supplied to the burner located in the lower chamber of the oven via a pipe connection to the gas cylinder. Perforations allow for heat dissipation within the lower chamber. Capacity of the baking oven is 12 loaves of bread of 0.5 kg per bread per tray (batch). Using a temperature regulator and from practical determination, the maximum temperature of 210°C was recorded. The performance test on the oven showed that the efficiency of the oven is of 90.7 percent. The oven can be adapted for both domestic and industrial purposes and have been found very useful in bakery industries. The oven was constructed with locally available materials. Estimated production cost is N56, 470 which is $156.86 at the exchange rate of 360 Naira to a US Dollar as at the time of this design. This can be seen in the Bill of Engineering Measurement and Evaluation (BEME) shown in the report.

Minimum Corrosion For Butane Isomerization Units—A Contribution to the Work of NACE Group Committee T-8 On Refining Industry Corrosion(1),★

A review is made of corrosion problems associated with butane isomerization units. In this connection, vapor-phase and liquid-phase butane isomerization are considered separately. Data reported include corrosion rates of nickel and Monel in HCl at 30 C, corrosion of Hastelloy alloys A and B in HCl at room temperature, effect of temperature on corrosion of nickel and Monel in 5 percent HCl, and corrosion of Type 1 Ni-Resist in unaerated HCl at room temperature. In butane isomerization units it is important that the feed be kept dry and that such impurities as sulfur, pentanes and olefins be reduced to a minimum. Adequate guard chamber capacity is a must. Alloys must be carefully selected for use in locations where corrosion is severe. 8.4.3

On the measurement of the ratio of the specific heats using small volumes of gas.—The ratios of the specific heat of air and of hydrogen at atmospheric pressure and a temperatures between 20°C. and —183°C

Introduction .—In nearly all the previous determinations of the ratio of the specific heats of gases, from measurements of the pressures and temperature before and after an adiabatic expansion, large expansion chambers of fror 50 to 130 litres capacity have been used. Professor Callendar first suggests the use of smaller vessels, and in 1914, Mercer (‘Proc. Phys. Soc.,’ vol. 26 p. 155) made some measurements with several gases, but at room temperature only, using volumes of about 300 and 2000 c. c. respectively. He obtained values which indicated that small vessels could be used, and that, with proper corrections, a considerable degree of accuracy might be obtained. The one other experimenter who has used a small expansion chamber, capacity about 1 litre, is M. C. Shields (‘Phys. Rev.,’ 1917), who measured this ratio for air and for hydrogen at room temperature, about 18° C., and its value for hydroger at — 190° C. The chief advantage gained by the use of large expansion chambers is that no correction, or at the most, a very small one, has to be made for any systematic error due to the size of the containing vessels, but it is clear that, in the determinations of the ratio of the specific heats of gases at low temperatures, the use of small vessels becomes a practical necessity in order that uniform and steady temperature conditions may be obtained. Owing, however, to the presence of a systematic error depending upon the dimensions of the expansion chamber, the magnitude of which had not been definitely settled by experiment, the following work was undertaken with the object of investigating the method more fully, especially with regard to it? applicability to the determination of this ratio at low temperatures.

Constants of explosion of cordite and of modified cordite

Objects of the Investigation .—These were to determine, under the conditions of pressure obtaining in a gun, the constants of explosion of cordite and of modified cordite, with special reference to the effects produced by the non­-explosive ingredients, mineral jelly and acetone. The large increase in the percentage of guncotton which characterises modified cordite causes the retention of a greater quantity of volatile matter than was found in the older cordite ; the nature of this volatile matter and its effects on the constants of explosion are examined. Apparatus and Procedure .—The bomb, made to the design of Colonel Holden, F. R. S., at the Royal Gun Factory, had a chamber capacity of 128·32 c. c., was made of gun steel of about 3·3 cm. in thickness, and was fitted with arrangements for obturation and electrical insulation of the firing-pin and for drawing off the gases, which worked well in practice (diagram accompanies paper). The calorimeter and method of ascertaining the water equivalent of the apparatus are described (diagram), as are also the procedure when a shot is fired (diagram) and the means adopted for collecting and measuring the gases evolved (diagram).