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1.
Multipurpose incinerators for bulky industrial waste . The rising cost of fuel and power has forced us to develop new and improved methods also in the disposal of bulky industrial waste. A series of factors must be taken into consideration. For the conventional technique of incineration it would at first appear that the efficient disposal of bulky industrial waste presents an almost insurmountable problem. However, practical experience gained on various plants has shown that there are a number of useful solutions to the problem. It is possible to incinerate bulky industrial waste up to certain unit sizes in an ecologically unobjectionable manner. In the long term, considerable economical advantages are forseeable. However, detailed planning is indispensible for the optimization of such processes.  相似文献   

2.
Multipurpose batch processes entail various operational policies that have been widely investigated in published literature. In this paper, no-intermediate-storage (NIS), zero-wait (ZW) and common-intermediate-storage (CIS) operational policies are of particular interest. In all these policies, no dedicated storage facility is available between two consecutive units. Unlike the other operational policies, these particular policies bear some subtle practical infeasibility that has gone unnoticed in literature. In essence, this infeasibility has been reported as optimal, thus assumed to be feasible, by various authors using mathematical programming techniques. It pertains to a unit transferring product to one or more units whilst simultaneously receiving feed from another, which is practically infeasible and as such need not be considered as a possible solution. This feature is particularly conspicuous in batch processes with complex recipes wherein production paths can be in opposite directions. This paper presents the unique feature of the S-graph framework to isolate cross-transfer during optimization, whereas the available mathematical programming methods inherently fail neither to detect nor to eliminate this infeasibility. A few examples taken from published literature are presented for demonstration purposes.  相似文献   

3.
In order to survive in a hostile habitat, plants have to manage the available resources to reach a delicate balance between development and defense processes, setting up what plant scientists call a trade-off. Most of these processes are basically responses to stimuli sensed by plant cell receptors and are influenced by the environmental features, which can incredibly modify such responses and even cause changes upon both molecular and phenotypic level. Therefore, significant differences can be detected between plants of the same species living in different environments. The comprehension of plant growth-defense trade-offs from the molecular basis to the phenotypic expression is one of the fundamentals for developing sustainable agriculture, so with this review we intend to contribute to the increasing of knowledge on this topic, which have a great importance for future development of agricultural crop production.  相似文献   

4.
5.
The need for flame-retardant finishing of textiles is examined in the context of the hazards of textile flammability, associated legislation and procedures for assessing textile burning behaviour. The functions of flame-retardant finishes and durable finishes developed specifically for cellulose, wool and man-made fibres are described in depth. Multipurpose finishes for both cellulose and wool textiles in which flame retardancy is only one property conferred on the textile are examined. Fibre blends present a particular problem and special attention is paid to discussing those finishes applied to polyester/cotton blended fabrics. The laundering behaviour and consequent finish durability are reviewed. In addition, the effects that applying flame-retardant finishes have on textile properties and performance are considered. Recent developments in methods used to apply flame-retardant finishes are outlined.  相似文献   

6.
Planning of Coupled Production in Multipurpose Chemical Plant. This article considers strategies for computer-aided planning of coupled production for systems of net worked multipurpose plant. Reasons are given for the failure of classical strategies such as are used in PPS systems. A procedure is described which, starting from a final product, automatically generates a cascade of previous product jobs and assigns them to production lines along a time axis (simultaneous material, pecursor, and production line assignment planning). Possibilities of interactive improvements of a given solution on consideration of factors such as storage costs and turnover are presented.  相似文献   

7.
Ecdysteroids (ECs) are steroid hormones originally found in the animal kingdom where they function as insect molting hormones. Interestingly, a relatively high number of these substances can also be formed in plant cells. Moreover, ECs have certain regulatory effects on plant physiology, but their role in plants still requires further study. One of the main aims of the present study was to verify a hypothesis that fenarimol, an inhibitor of the biosynthesis of ECs in the animal kingdom, also affects the content of endogenous ECs in plants using winter wheat Triticum aestivum L. as a model plant. The levels of endogenous ECs in winter wheat, including the estimation of their changes during a course of different temperature treatments, have been determined using a sensitive analytical method based on UHPLC-MS/MS. Under our experimental conditions, four substances of EC character were detected in the tissue of interest in amounts ranging from less than 1 to over 200 pg·g−1 FW: 20-hydroxyecdysone, polypodine B, turkesterone, and isovitexirone. Among them, turkesterone was observed to be the most abundant EC and accumulated mainly in the crowns and leaves of wheat. Importantly, the level of ECs was observed to be dependent on the age of the plants, as well as on growth conditions (especially temperature). Fenarimol, an inhibitor of a cytochrome P450 monooxygenase, was shown to significantly decrease the level of naturally occurring ECs in experimental plants, which may indicate its potential use in studies related to the biosynthesis and physiological function of these substances in plants.  相似文献   

8.
Saudi Arabia is an arid desert country without rivers or sweet water lakes, however, it does have vast amount of groundwater and seawater. In order to make these waters suitable for human consumption and industrial use, most of their salts must be removed by some means. The desalination methods most frequently used in the Kingdom are: Multistage flash (MSF) evaporation, reverse osmosis (RO), and electrodialysis (ED).During the last decade, we have witnessed a spectacular growth of desalination plants. This growth is expected to continue in the next decade. The present production capacity of all desalting plants in Saudi Arabia is estimated to be 750,000 m3/day; this figure will be most likely tripled in the next five years.This paper is a report on a performance study of the most significant desalination plants in the Kingdom. The plants, which include MSF and seawater and brackish water RO plants, were selected either because of their size or their importance to the desalination technology. The plants are briefly described and their performances are discussed.  相似文献   

9.
Along the Gulf Coast there are three Saudi main desalination sites. These are, South to North, Al-Khobar, Al-Jubail and Al-Khafji. In these plants some 300 MIGD of distillate could be produced when all 58 MSF evaporators are run at a low top brine temperature (TBT) of 90°C. An additional 50 MIGD could be produced when the 52 evaporators designed as well, for high TBT of 113°C or more are run near this temperature. All these 58 evaporators are designed with additive scale control. Therefore additive treatment and cost are vital to East Coast Saudi Arabian plants.This paper will review original design operating parameters and performance. It will also report on some revisions reviewed or developed and executed at these plants. The changes were developed and adopted in an attempt to optimize production cost particularly scale control additive dose levels at different top temperatures. These plants were designed and undergone performance and trial runs at additive dose levels of 12 to 3 ppm. These were then reduced after the warranty periods to extremely low values of 2.2 to 0.8 ppm at different top temperatures.  相似文献   

10.
Rapid changes in the Earth’s atmosphere and climate associated with human activity can have significant impacts on agriculture including livestock production. CO2 concentration has risen from the industrial revolution to the current time, and is expected to continue to rise. Climatic changes alter physiological processes, growth, and development in numerous plant species, potentially changing concentrations of plant secondary compounds. These physiological changes may influence plant population density, growth, fitness, and toxin concentrations and thus influence the risk of toxic plants to grazing livestock. Locoweeds, swainsonine-containing Astragalus species, are one group of plants that may be influenced by climate change. We evaluated how two different swainsonine-containing Astragalus species responded to elevated CO2 concentrations. Measurements of biomass, crude protein, water soluble carbohydrates and swainsonine concentrations were measured in two chemotypes (positive and negative for swainsonine) of each species after growth at CO2 levels near present day and at projected future concentrations. Biomass and water soluble carbohydrate concentrations responded positively while crude protein concentrations responded negatively to elevated CO2 in the two species. Swainsonine concentrations were not strongly affected by elevated CO2 in the two species. In the different chemotypes, biomass responded negatively and crude protein concentrations responded positively in the swainsonine-positive plants compared to the swainsonine-negative plants. Ultimately, changes in CO2 and endophyte status will likely alter multiple physiological responses in toxic plants such as locoweed, but it is difficult to predict how these changes will impact plant herbivore interactions.  相似文献   

11.
North Carolina contains several extensive areas of shale deposits, which are favorably located for working and which in their slightly weathered condition have been recently found to be well adapted to the manufacture of face brick, hollow blocks, sewer pipes, etc. As a result of these discoveries a number of clay working plants have been recently set in operation and others are in course of construction.  相似文献   

12.
Plants have evolved several adaptive strategies through physiological changes in response to herbivore attacks. Plant secondary metabolites (PSMs) are synthesized to provide defensive functions and regulate defense signaling pathways to safeguard plants against herbivores. Herbivore injury initiates complex reactions which ultimately lead to synthesis and accumulation of PSMs. The biosynthesis of these metabolites is regulated by the interplay of signaling molecules comprising phytohormones. Plant volatile metabolites are released upon herbivore attack and are capable of directly inducing or priming hormonal defense signaling pathways. Secondary metabolites enable plants to quickly detect herbivore attacks and respond in a timely way in a rapidly changing scenario of pest and environment. Several studies have suggested that the potential for adaptation and/or resistance by insect herbivores to secondary metabolites is limited. These metabolites cause direct toxicity to insect pests, stimulate antixenosis mechanisms in plants to insect herbivores, and, by recruiting herbivore natural enemies, indirectly protect the plants. Herbivores adapt to secondary metabolites by the up/down regulation of sensory genes, and sequestration or detoxification of toxic metabolites. PSMs modulate multi-trophic interactions involving host plants, herbivores, natural enemies and pollinators. Although the role of secondary metabolites in plant-pollinator interplay has been little explored, several reports suggest that both plants and pollinators are mutually benefited. Molecular insights into the regulatory proteins and genes involved in the biosynthesis of secondary metabolites will pave the way for the metabolic engineering of biosynthetic pathway intermediates for improving plant tolerance to herbivores. This review throws light on the role of PSMs in modulating multi-trophic interactions, contributing to the knowledge of plant-herbivore interactions to enable their management in an eco-friendly and sustainable manner.  相似文献   

13.
液化天然气(LNG)工业曾经在相当长的一段时间里都把注意力放在陆上大规模基荷型(base-load LNG)液化项目。近几年来,LNG工业开始显现出一些新的发展趋势,如北美的页岩气热、海上天然气资源的开发、使用LNG作为车船用燃料以及在极寒地区建设液化设施等。这些新趋势带来新的挑战,要求人们对工艺技术选择进行谨慎思考。在这个大背景下,最近筹建和在建的新兴LNG项目多具有与传统项目不同的特征,如原料气来源、驱动方式与燃料要求、海洋运动对设备的影响以及外部气候条件等。与此同时,这些项目在可靠性、易操作性、效率和产能等方面也具有不同的要求和侧重点。本文首先对传统基荷型LNG项目在液化工艺技术方面需要考虑的问题进行综述,然后重点论述如何针对新LNG项目优化这些问题以期达到更好的投资回报。以使用2个LNG项目作为案例分析,来展示如何进行正确的工艺技术选择以保证项目成功。  相似文献   

14.
Plants must adapt to cope with adverse environmental conditions that affect their growth and development. To overcome these constraints, they can alter their developmental patterns by modulating cellular processes and activating stress-responsive signals. Alongside the activation of the antioxidant (AOX) system, a high number of genes are expressed, and proteins must be distributed to the correct locations within the cell. The endomembrane system and associated vesicles thus play an important role. Several pathways have been associated with adverse environmental conditions, which is the case for the exocyst-positive organelle—EXPO. The present work, using Arabidopsis mutants with T-DNA insertions in the gene EXO70, essential for EXPO vesicles formation, was designed to characterise the anatomical (morphology and root length), biochemical (quantification of stress markers and antioxidant system components), and molecular responses (gene expression) to abiotic stresses (saline, drought, oxidative, and metal-induced toxicity). The results obtained showed that mutant plants behave differently from the wild type (WT) plants. Therefore, in the exo70 mutant, morphological changes were more noticeable in plants under stress, and the non-enzymatic component of the antioxidant system was activated, with no alterations to the enzymatic component. Furthermore, other defence strategies, such as autophagy, did not show important changes. These results confirmed the EXPO as an important structure for tolerance/adaptation to stress.  相似文献   

15.
Under natural environments, light quality and quantity are extremely varied. To respond and acclimate to such changes, plants have developed a multiplicity of molecular regulatory mechanisms. Non-photochemical quenching of chlorophyll fluorescence (NPQ) and thylakoid protein phosphorylation are two mechanisms that protect vascular plants. To clarify the role of thylakoid protein phosphorylation in energy-dependent quenching of chlorophyll fluorescence (qE) in rice plants, we used a direct Western blot assay after BN-PAGE to detect all phosphoproteins by P-Thr antibody as well as by P-Lhcb1 and P-Lhcb2 antibodies. Isolated thylakoids in either the dark- or the light-adapted state from wild type (WT) and PsbS-KO rice plants were used for this approach to detect light-dependent interactions between PsbS, PSII, and LHCII proteins. We observed that the bands corresponding to the phosphorylated Lhcb1 and Lhcb2 as well as the other phosphorylated proteins were enhanced in the PsbS-KO mutant after illumination. The qE relaxation became slower in WT plants after 10 min HL treatment, which correlated with Lhcb1 and Lhcb2 protein phosphorylation in the LHCII trimers under the same experimental conditions. Thus, we concluded that light-induced phosphorylation of PSII core and Lhcb1/Lhcb2 proteins is enhanced in rice PsbS-KO plants which might be due to more reactive-oxygen-species production in this mutant.  相似文献   

16.
Water, re-entering a marine ecosystem after transit through a desalination plant, may be altered in three major ways. One, its thermal energy may be increased; two, its chemical make up may be altered; and three, its microbial biota may be modified. The effect of thermal enrichment on natural marine ecosystems varies with the change in temperature, the duration of that temperature change, and its geographical extent. If the desalination plant is sited in such a manner so as to allow rapid dissipation of the thermal input, the effect of the temperature change will be minimized. Signs of thermal effect on marine ecosystems could be manifested by changes in community structure (types of organisms), as well as the changes in features of individual species. The most obvious chemical changes in desalination effluents may include increase in salinity, a decrease in dissolved oxygen, an increase in dissolved organics, and an increase in pretreatment chemicals. As with thermal input, the effect of these chemical changes in the effluent on natural ecosystem will depend upon the rate of entrance and dispersion. As the rate of dispersion is increased, the effect of chemical changes on ecosystems is correspondingly decreased. Desalination plants, due to their design, provide surface areas for rapid microbial proliferation. Depending upon the sequence of chemical pretreatment, it is possible that these viable microbes will enter the ecosystem and supplement the existing biota, if conditions permit their continued growth.The environmental impact in several types of desalination plants (distillation and reverse osmosis) on natural marine ecosystems will be discussed. The problems imposed on the environment by these desalination plants will be presented and similarities to problems encountered in other types of condenser-heat exchanger systems (Power plants and ocean thermal energy converters) will be analyzed.  相似文献   

17.
On the Future of Solid Processing Techniques The chemical industry is experiencing major changes. The experts of the “Solids Processing Industrial Network” expect that in the future two kinds of chemical plants will develop: on the one hand the polyvalent, multipurpose, modular plant and on the other hand the world‐scale plants. At the same time the high percentage of solids as products of chemical processes will continue to increase and therefore new challenges have to be met. Small‐scale production of solids has to be customized to the individual customer needs, which means that product design will be a technology that defines the competitiveness. For large plants techniques have to be developed that enable large volumes to be produced but that also allow the reliable scale‐up from laboratory scale to world‐scale production. Automatization will play a crucial role in the success of solids processing, which will depend on the availability of on‐line measurement systems and the development of simulation models for the processes and the particle properties involved.  相似文献   

18.
Fatty acids serve many functions in plants, but the effects of some key genes involved in fatty acids biosynthesis on plants growth and development are not well understood yet. To understand the functions of 3-ketoacyl-acyl-carrier protein synthase I (KASI) in tobacco, we isolated two KASI homologs, which we have designated NtKASI-1 and NtKASI-2. Expression analysis showed that these two KASI genes were transcribed constitutively in all tissues examined. Over-expression of NtKASI-1 in tobacco changed the fatty acid content in leaves, whereas over-expressed lines of NtKASI-2 exhibited distinct phenotypic features such as slightly variegated leaves and reduction of the fatty acid content in leaves, similar to the silencing plants of NtKASI-1 gene. Interestingly, the silencing of NtKASI-2 gene had no discernibly altered phenotypes compared to wild type. The double silencing plants of these two genes enhanced the phenotypic changes during vegetative and reproductive growth compared to wild type. These results uncovered that these two KASI genes had the partially functional redundancy, and that the KASI genes played a key role in regulating fatty acids synthesis and in mediating plant growth and development in tobacco.  相似文献   

19.
Effects of Genetic Modification on Herbivore-Induced Volatiles from Maize   总被引:3,自引:0,他引:3  
Large-scale implementation of transgenic crop varieties raises concerns about possible nontarget effects on other organisms. This study examines the effects of genetic modification on plant volatile production and its potential impact on arthropod population dynamics. We compared herbivore-induced volatile emissions from Bacillus thuringiensis Berliner (Bt) maize plants to those from a nontransformed isoline following exposure to various types of leaf damage. When equal numbers of Helicoverpa zea Boddie (Lepidoptera: Noctuidae) larvae fed on Bt and non-Bt maize, volatile emissions were significantly lower in the transgenic plants, which also exhibited less leaf damage. When damage levels were controlled by adding more larvae to Bt plants, the plants' volatile emissions increased but displayed significant differences from those of nontransgenic plants. Significantly higher amounts of linalool, β-myrcene, and geranyl acetate were released from transgenic maize than from non-Bt plants. Manipulating the duration of feeding by individual larvae to produce similar damage patterns resulted in similar volatile profiles for Bt and non-Bt plants. Controlling damage levels more precisely by mechanically wounding leaves and applying larval regurgitant likewise resulted in similar emission patterns for Bt and non-Bt maize. Overall, changes in the herbivore-induced volatile profiles of Bt maize appeared to be a consequence of altered larval feeding behavior rather than of changes in biochemical plant defense pathways. The implications of these findings for understanding the impacts of plant-mediated cues on pest and natural enemy behavior in transgenic crop systems are discussed.  相似文献   

20.
Crystal-bearing cells or idioblasts, which deposit calcium oxalate, are located in various tissues and organs of many plant species. The functional significance of their formation is currently unclear. Idioblasts in the leaf parenchyma and the development of crystal-bearing cells in the anther tissues of transgenic tomato plants (Solanum lycopersicon L.), expressing the heterologous FeSOD gene and which showed a decrease in fertility, were studied by transmission and scanning electron microscopy. The amount of calcium oxalate crystals was found to increase significantly in the transgenic plants compared to the wild type (WT) ones in idioblasts and crystal-bearing cells of the upper part of the anther. At the same time, changes in the size and shape of the crystals and their location in anther organs were noted. It seems that the interruption in the break of the anther stomium in transgenic plants was associated with the formation and cell death regulation of a specialized group of crystal-bearing cells. This disturbance caused an increase in the pool of these cells and their localization in the upper part of the anther, where rupture is initiated. Perturbations were also noted in the lower part of the anther in transgenic plants, where the amount of calcium oxalate crystals in crystal-bearing cells was reduced that was accompanied by disturbances in the morphology of pollen grains. Thus, the induction of the formation of crystal-bearing cells and calcium oxalate crystals can have multidirectional effects, contributing to the regulation of oxalate metabolism in the generative and vegetative organs and preventing fertility when the ROS balance changes, in particular, during oxidative stresses accompanying most abiotic and biotic environmental factors.  相似文献   

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