Simultaneous heat exchanger network synthesis for direct and indirect heat transfer inside and between processes

Process plants are typically divided into different process parts having specific processing tasks with possibly different ownership. Heat integration between these processes can increase the energy- and economic efficiency for both the overall plant and the individual processes. In this paper we present a heat exchanger network synthesis MINLP-model that allows simultaneous heat integration directly between streams in the same process and both directly and indirectly between streams in different processes. The indirect heat transfer is accomplished by using intermediate streams. Two examples, one small explanatory one and one from the literature, are optimized. The results verify that the model works logically.     

网络拱桥──一种适合中国的桥梁

阐述了网络拱桥的特点，设计原理，节点形式及架设安装。对中国大跨度简支架桥的发展有一定的借鉴作用．     

Ideas on downward arched and other underwater concrete tunnels

The downward arched submerged floating tunnel (SFT) with no stays is the most economical alternative for free spans up to 1.5 km in deep Norwegian fjords, and in fjords with similar conditions. The SFT is reached through tunnels in the solid rock at both shores. When the clay bed method is used for supporting tunnels with square cross-section, clay can be pumped through the floor to compensate for settlements during the life-time of the tunnel.     

A framework for local and regional energy system integration between industry and municipalities—Case study UPM-Kymmene Kaukas

The integration of different energy systems, e.g., industrial and municipal, is potentially important for the efficient utilization of energy. It is important that the tools for analysing this type of integration can handle the energy systems on different levels, e.g., regional, site, plant and process levels. In this work, a framework for investigating the cost-efficient integration of large-scale energy systems is presented and tested at the UPM-Kymmene Kaukas pulp and paper plant and in the municipality of Lappeenranta, Finland. In addition to the different levels, the framework also aims to take into account several sub-problems, e.g., fuel logistic, optimal heat exchanger network and overall efficiency versus flexibility. The case in question shows that the presented framework can be used as a systematic tool for analysing the potential of integrating large energy systems and that it is able to handle both the synthesis of flexible heat exchanger networks and analyse the cost-efficiency of changes to the existing systems.     

Changes in folate status as determined by reduction in total plasma homocysteine levels during leucovorin modulation of 5-fluorouracil therapy in cancer patients

We measured plasma total homocysteine (tHcy) in 14 patients (13 patients with colorectal cancer and 1 patient with breast cancer) during their first treatment with 5-fluorouracil (5-FU) plus leucovorin [LV (5-FULV)]. Eight of these patients were investigated a second time after 3-10 cycles (median, 4 cycles) with 5-FULV. Each cycle consisted of two administrations of 5-FU (500 mg/m2) and LV (60 mg/m2) given 24 h apart. The first administration of 5-FULV on day 1 of the first cycle induced a rapid reduction of the tHcy level from 12.5 micromol/liter (10.4-15.1 micromol/liter; geometric mean with 95% confidence interval of the mean) to 9.1 micromol/liter (7.5-11.1 micromol/liter) in 24 h. tHcy remained stable at this level after the second administration of 5-FULV. In addition, the 5-FULV regimen caused a concurrent 4-fold increase in both serum and erythrocyte folate. The fifth cycle with 5-FULV had only marginal effects on the tHcy level. 5-FU without LV modulation had no effect on the plasma tHcy or folate status in eight breast cancer patients. Our data establish the reduction of tHcy as a responsive indicator of LV pharmacodynamics.     

Key concepts in a framework for analysing visual landscape character

A transparent and theory-based scheme for analysing visual character is presented. Based on a literature review, nine key visual concepts are identified: stewardship, coherence, disturbance, historicity, visual scale, imageability, complexity, naturalness and ephemera. The nine visual concepts are presented in a framework of four levels of abstraction, described through the concepts' visual dimensions, landscape attributes contributing to the concepts and potential visual indicators suggested for mapping and quantifying the concepts. Each of these concepts focuses on different aspects of the landscape important for visual quality, where visual quality is an holistic experience of them all. The visual concepts presented are used to describe different characteristics of visual landscapes, rather than presenting a normative value for visual quality. It is believed that this framework can be important for landscape assessment and the compilation of landscape character.     

Relationships between visual landscape preferences and map-based indicators of landscape structure

There is increasing awareness of the need to monitor trends in our constantly changing agricultural landscapes. Monitoring programmes often use remote sensing data and focus on changes in land cover/land use in relation to values such as biodiversity, cultural heritage and recreation. Although a wide range of indicators is in use, landscape aesthetics is a topic that is frequently neglected. Our aim was to determine whether aspects of landscape content and configuration could be used as surrogate measures for visual landscape quality in monitoring programmes based on remote sensing. In this paper, we test whether map-derived indicators of landscape structure from the Norwegian monitoring programme for agricultural landscapes are correlated with visual landscape preferences. Two groups of people participated: (1) locals and (2) non-local students. Using the total dataset, we found significant positive correlations between preferences and spatial metrics, including number of land types, number of patches and land type diversity. In addition, preference scores were high where water was present within the mapped image area, even if the water itself was not visible in the images. When the dataset was split into two groups, we found no significant correlation between the preference scores of the students and locals. Whilst the student group preferred images portraying diverse and heterogeneous landscapes, neither diversity nor heterogeneity was correlated with the preference scores of the locals. We conclude that certain indicators based on spatial structure also have relevance in relation to landscape preferences in agricultural landscapes. However, the finding that different groups of people prefer different types of landscape underlines the need for care when interpreting indicator values.     

Integrating landscape-based values—Norwegian monitoring of agricultural landscapes

An accumulating body of research identifies the importance of landscape structure for a wide range of countryside interests. Landscape structure reflects the results of policies and practices, and is well-suited as a target for management actions. New landscape metrics represent a potential for indicator-based management, provided such metrics relate consistently to the landscape values of interest. In this paper we propose that aspects of landscape structure, specifically heterogeneity, may be related to landscape-based values such as biodiversity, cultural heritage and human appreciation. Birds and vascular plants correlated well with our index for the heterogeneity of land types, whereas insects did not. Occurrence of prehistoric graves was also associated with land type heterogeneity, though other types of cultural remains were not. Landscape experience seems to be associated with the heterogeneity of landscape space rather than heterogeneity of land types. Different aspects of heterogeneity, scale, and variation over time all contribute to explain how our measures of landscape-based values vary in their relationship to landscape heterogeneity. Successful integration between disciplines in landscape studies depends on having a common operational framework, a shared theoretical basis, and a harmonised approach to data collection.     

Model study for subsurface trajectory of 75FeSi and SiMn ferroalloys in steel

The present study, using a low temperature model, is aimed at examining the feasibility of subsurface melting of 75FeSi and SiMn alloys added to steel baths. Wooden objects, simulating 75FeSi and SiMn of various sizes and shapes, were prepared so as to have same density ratio of 75FeSi and SiMn to steel, and their subsurface trajectories in water or zinc chloride solution following three meters of free fall through air were analyzed using video images. In general, subsurface retention times were observed to gradually increase with size of object up to a steady value. For those objects simulating 75FeSi, it was found to be dependent on shapes, spherical objects having longer retention times. The effect of shape was less pronounced for objects simulating SiMn. In a gas stirred bath, smaller cuboids for SiMn were entrained. Comparisons with estimated melting times of 75FeSi suggest that regular sized 75FeSi (ex. 20 to 50 mm) will float up and melt at the surface, when dropped to the steel bath in a ladle. A similar situation is expected with SiMn alloys. Subsurface melting may be feasible by reducing the size of 75FeSi addition from 1 to 5 mm dia. and of SiMn down to about 10 mm while simultaneously applying sufficient turbulent mixing of steel bath or providing entraining downflow velocities in the range of 10 to 30 cm/s.