Improved heat exchanger networks for energy conservation in palm oil refineries

In designing a network of heat exchangers for the recovery of waste heat, there is usually a'pinch' at which the minimum approach temperature difference limits energy recovery. Pinch technology emphasizes the importance of utility targets, which are independent of the network design, and so allow a very useful comparison with the utility requirements of actual networks. The design of a heat recovery network of exchangers used in palm oil refining has been examined using such pinch technology targeting procedures. The network was found to be well designed for the situation where steam is a cheaper utility than hot oil. As this was not the case, improved networks were designed. These allowed a significant reduction in heat exchanger surface area for the same energy consumption, or a 25% reduction in energy consumption for a modest increase in network area of about 10%.     

涤纶网络丝仿麻织物的摩擦性能

为改善涤纶网络丝仿麻织物的摩擦性能,分析了纤维、纱线、织物组织结构等因素对涤纶网络丝仿麻织物起毛起球性能、耐磨性能的影响,研究并制定了提高涤纶网络丝仿麻织物摩擦性能的树脂整理工艺。对树脂整理剂浓度、处理液温度、焙烘温度、焙烘时间、柔软剂浓度等工艺参数进行优化。结果表明:涤纶网络丝仿麻织物最佳整理工艺为树脂整理剂质量浓度50 g/L,处理液温度40 ℃,焙烘温度100 ℃,焙烘时间4 min,柔软剂质量浓度3 g/L;经最佳工艺整理后的织物在40 000次摩擦后的质量损失率由未整理时的12.13%下降到 5.34%,织物起毛起球等级由未整理时的1级提升到3~4级,并能基本保持织物原有的手感。     

The effect of adding herbs to labneh on physicochemical and organoleptic quality during storage

The aim of this study was to investigate the influence of different herbs on physicochemical and organoleptic quality of labneh during storage. Analyses were carried out at 10‐day intervals in a storage period of 30 days. There were to significant differences in dry matter, fat and ash contents of the labneh samples. The pH and titratable acidity values were influenced by herbs and storage periods. Adding herb to labneh altered the colour: L* values in all samples decreased, whereas a* and b* values were affected differently from herbs added. Calcium content of the labneh decreased with the addition of herbs, but phosphorus, iron, copper and zinc contents increased. The sensorial scores of the labneh samples were influenced by the variety of herb added and the storage times. Addition of dill and parsley to labneh resulted in the greatest sensory scores.     

Experimental investigation of multiphase flow behavior in drilling annuli using high speed visualization technique

Imaging with high definition video camera is an important technique to visualize the drilling conditions and to study the physics of complex multiphase flow associated with the hole cleaning process. The main advantage of visualizing multiphase flow in a drilling annulus is that the viewer can easily distinguish fluid phases, flow patterns and thicknesses of cutting beds. In this paper the hole cleaning process which involves the transportation of cuttings through a horizontal annulus was studied. The two-phase (solid-liquid) and the three-phase (solid-liquid-gas) flow conditions involved in this kind of annular transportation were experimentally simulated and images were taken using a high definition camera. Analyzing the captured images, a number of important parameters like velocities of different phases, heights of solid beds and sizes of gas bubbles were determined. Two different techniques based on an image analysis software and MATLAB coding were used for the determinations. The results were compared to validate the image analyzing methodology. The visualization technique developed in this paper has a direct application in investigating the critical conditions required for efficient hole cleaning as well as in optimizing the mud program during both planning and operational phases of drilling. Particularly, it would be useful in predicting the cuttings transport performance, estimating solid bed height, gas bubble size, and mean velocities of bubbles/particles.     

CHARACTERISTICS OF BEEF PATTIES USING OKARA POWDER

Four different levels of okara powder (2.5, 5.0, 7.5 and 10%) were used to obtain beef patties that were compared with controls with 10 and 20% fat. Okara addition affected some quality parameters of beef patties. Although the protein, fat, ash and carbohydrate contents of raw beef patties increased by the addition of okara, moisture content decreased. The same trends (except protein content) were observed after cooking. The addition of okara reduced the cholesterol content by about 2–28% for raw beef patties and 6–23% for cooked beef patties. However, addition of okara increased the energy values for raw and cooked beef patties with respect to control with 10% fat. The WHC, cook loss and shrinkage of beef patties improved by the addition of okara. The addition of okara increased the pH, L* and b* values of raw beef patties, but did not affect a* value. The effect of okara on the sensory properties was statistically significant and the overall acceptability scores of samples decreased after more than 7.5% okara powder addition . According to these results, addition of okara powder up to 7.5% can be recommended as an extender in beef patties production to improving certain quality parameters.

PRACTICAL APPLICATIONS

Okara is an abundant by-product of the soy and tofu industries and contains valuable components, including proteins, lipids, fibers and isoflavonoids. The addition of okara powder to beef patties reduces the cholesterol content and improves WHC, cook loss, shrinkage and sensory quality of the products. Okara powder can be added up to 7.5% for the production of patties.     

Finite element analysis of magnetic disk with a horizontal subsurface crack

Sliding contact of a rigid rough surface with a semi‐infinite medium including a horizontal subsurface crack was investigated by using linear elastic fracture mechanics and finite element method (FEM). The fractal geometry was used to characterize the rigid rough surface. The propagation of crack was studied with the shear and tensile stress intensity factors. The effect of surface roughness, crack length to depth ratio and friction at the contact and crack interfaces was investigated by using the FEM. It was shown that increasing friction coefficient at the contact interface increases both K_II and K_I.     

LAGRANGE MULTIPLIERS FOR THE INTERMEDIATE METALLIC REGIONS IN THE COMPUTATION OF THE POTENTIAL DISTRIBUTION OF INSULATOR CHAINS BY FEM

ABSTRACT

It is very important to predict the behaviour of the high voltage insulators at the operating conditions from the point of improving of the design and practical selection of the insulator type. Therefore, it is necessary to compute the potential and electric field distributions and to determine the critical regions forced much more by the electric field. In case the insulator surface is clean or the pollution film at the surface is dry, a little capacitive current flows and the solution of the problem results in a capacitive potential distribution.

In the numerical computational methods of potential distribution of insulator chains, it requires to insert into the resulting equation system as boundary conditions of the intermediate metallic zones that connect two units that have the same potential at every point. In this work, the potential distribution of clean insulator chains have been computed using the Finite Element Method (FEM). The metallic zones between the units have been taken into account as equipotential surfaces by Lagrange Multipliers. The computed results were compared with experimental results obtained by using the Conducting Paper Method and good agreement was observed.     

BOILING TWO-PHASE FLOW HEAT TRANSFER IN A HORIZONTAL BEND

Abstract

A paucity of heat transfer rate data for boiling two-phase flow through bends was noted after an extensive literature survey, The present work was undertaken to redress this shortcoming.

A boiling water loop, capable of being operated at pressures up to 1300 kpa, was used. The lest section was in the form of a U-tube with two straight horizontal sections connected by a 180^° return bend. Using this loop, pressure drop and heat transfer data were gathered over a wide range of mass and heat fluxes. steam qualities and system pressures.

The data obtained were used to investigate the variation in heal transfer coefficients around the radial positions of the bend. Correlations for heat transfer coefficients for four different radial positions (top. bollom, inside and outside of the bend) have been presented for the first time. A possible explanation for the observed variations in heat transfer coefficients has also been suggested.     

The fatty acid levels and physicochemical properties of herby brined cheese, a traditional Turkish cheese

In this study, some gross chemical compositions and fatty characteristics of herby cheeses were investigated. In the present study, the cheeses used as materials were collected from 10 different plants. The cheeses were made from sheep milk, cow's milk or a mixture of them, and stored in brine at 7–8°C and analysed for some proximate chemical compositions and fatty acid composition after 150 days of ripening. Capric acid, palmitic acid, oleic acid, short-chain fatty acids, medium-chain fatty acids, long-chain fatty acids, saturated fatty acids, monounsaturated fatty acids, polyunsaturated fatty acids and other fatty acids as g in 100 g fatty acids were determined.