Multifactor Effects Research Articles

Pressure Behavior Analysis of Permeability Changes Due to Sand Production in Offshore Loose Sandstone Reservoirs Using Boundary-Element Method

In recent years, sand production has been frequently observed in offshore weakly consolidated sandstone reservoirs. Permeability changes due to sand migration seriously affect the confidence in well test interpretation, production forecasts, and oilfield development plan schedules. The purpose of this paper is to propose a comprehensive model of coupled sand migration, stress sensitivity, and high viscosity oil and to study the effect of sand production induced permeability zoning on transient pressure behavior by combining discrete boundary and discrete wellbore with the boundary element method. In this two-zone composite model, the reservoir can be divided into the inner zone with the improved permeability due to sand migration and the outer zone with initial reservoir permeability. The multifactor effects of stress-sensitive, highly viscous oil, sand migration, and horizontal well are included in this model. Thus, the seepage equation presents a highly nonlinear and difficult to obtain an accurate analytical solution. In this paper, the boundary element method (BEM) is introduced to separate the boundary and wellbore, and the semianalytical solution of the hybrid model is obtained. The comparative analysis of measured pressure curve fitting from a horizontal well, located in the eastern of the South China Sea, proves that this comprehensive model can be used for pressure transient analysis of the weakly consolidated sandstone reservoir. The flow regime analysis indicates that a two-zone composite system may develop seven flow regimes: the wellbore storage stage, early-time radial stage, first transition stage, inner linear stage, inner pseudoradial flow, transition flow from the inner area to the outer area, and outer pseudoradial flow. Sensitivity analysis indicates that the smaller the sand production radius, the shorter the duration of the transition flow from the inner to the outer zone, which suggests the well is mainly affected by the outer boundary in the later period. The larger the permeability ratio, the higher the pressure curves may move up.

Effects of Trace Components in Reclaimed Water Sludge on Wet Flue Gas Desulfurization Process

The paper designed and built a simulation reaction system for the Wet Flue Gas Desulfurization(WFGD) process to analyze the effects of factors on the Oxidation reaction of SO2 for the reuse of reclaimed water sludge. Six trace components including magnesium, iron, chloride, aluminum, PAM and PFS in reclaimed water sludge from reclaimed water softening were selected for analysis factors. The effects of six factors on the oxidation reaction were tested by single factor experiments. The multi-factor effects on the oxidation reaction was studied by adding different proportion of reclaimed water sludge to the desulfurizer of the simulated reaction system. In addition, the effect of reclaimed water sludge on the crystallization and dehydration of desulfurization slurry was analyzed. The results show that six factors have little effects on the SO2 oxidation rate in the test range. The addition of reclaimed water sludge has a significant effect on the crystalline form and dehydration of gypsum.

Risk factors related to bacterial contamination by <i>Enterobacteriaceae</i> and fecal coliforms and the prevalence of <i>Salmonella spp.</i> in Algerian farms, slaughterhouses and butcheries: a two-year follow-up study

<abstract> This study was conducted to investigate first the bacterial contamination by <italic>Enterobacteriaceae,</italic> fecal coliforms and the prevalence of <italic>Salmonella spp.</italic> and second to identify the main associated risk factors in Algerian farms, slaughterhouses and butcheries during a two-years period. Thus, a cross-sectional study was performed using a simple random sampling method to target 20 farms, 10 slaughterhouses and 5 butcheries. A structured questionnaire was further used to assess hygienic status of the farms and slaughterhouses. A total of 265 samples were collected from wall, floor, litter, food, water and animals' samples composed mainly of meat, neck skin and liver. Samples from walls and floors, from different sites were analyzed to evaluate the overall contamination and the hygiene of sites for Total viable bacteria, <italic>Enterobacteriaceae</italic> counts and Fecal coliforms counts. Furthermore, <italic>E.coli</italic> and <italic>salmonella spp</italic>. were identified in all samples. The overall contamination by sampling sites expressed as log_{10 CFU/g} (mean ± SD) for Total Aerobic Microbial Count, Enterobacteriaceae count and fecal coliforms counts were around 4.71 ± 1.1, 4.73 ± 1.3 and 4.68 ± 1.2 respectively. The findings evidenced that the prevalence of <italic>E.coli</italic> and <italic>Salmonella spp.</italic> were 63.40% and 18.49% respectively. The highest rate of <italic>E.coli</italic> contamination was for poultry farms (70%), beef farms (64%) and butcheries (74.54%) followed by poultry meat slaughterhouses (60%) and sheep farms (48%) while beef slaughterhouses have the lowest rate of contamination (33.84%). For <italic>salmonella spp.</italic> the contamination was found to be mainly in poultry meat slaughterhouses (31.11%), butcheries (25.45%), followed by poultry farms (22%), beef farms (20%) and sheep farms (12%) while beef slaughterhouses have the lowest rate of contamination (4.61%). This study evidenced multifactor effects of microbial contamination in farms such as animal density, litter hygiene and scraping, manure storage, water and pest control, contact with other animals and decontamination process. Overall, this trial indicated a high rate of microbial contamination for which further studies are needed to determine all the potential risk factors in order to evaluate the corrective effects. </abstract>

A method for the determination of optimal indoor environmental parameters range considering work performance

Work performance affected by single factors was extensively studied in previous studies. Little researches included quantitative interaction among environmental factors. Central composite design method was proved to be applicable for staff's performance considering multi-factor effects in this paper. Three parameters were mainly discussed: temperature, relative humidity, and fresh air. 18 subjects were recruited for neurobehavioral tasks. The results show that quadric multiple regression orthogonal model was suitable for work performance. Performance was significantly influenced by temperature and humidity, while the effect of fresh air was not as great as traditionally believed. In addition, the optimal ranges of temperature and relative humidity required for the relative performance of more than 95% were: 22.6 °C–26.0 °C and 50%–68%. Fresh air had limited positive effect on the improvement of performance within the setting range. The results obtained in this paper may contribute to the determination of environmental parameters in office buildings in the future. A novel idea for the study of multi-factor interaction in indoor environments was also provided.

Precision micro-milling process: state of the art

Micro-milling is a precision manufacturing process with broad applications across the biomedical, electronics, aerospace, and aeronautical industries owing to its versatility, capability, economy, and efficiency in a wide range of materials. In particular, the micro-milling process is highly suitable for very precise and accurate machining of mold prototypes with high aspect ratios in the microdomain, as well as for rapid micro-texturing and micro-patterning, which will have great importance in the near future in bio-implant manufacturing. This is particularly true for machining of typical difficult-to-machine materials commonly found in both the mold and orthopedic implant industries. However, inherent physical process constraints of machining arise as macro-milling is scaled down to the microdomain. This leads to some physical phenomena during micro-milling such as chip formation, size effect, and process instabilities. These dynamic physical process phenomena are introduced and discussed in detail. It is important to remember that these phenomena have multifactor effects during micro-milling, which must be taken into consideration to maximize the performance of the process. The most recent research on the micro-milling process inputs is discussed in detail from a process output perspective to determine how the process as a whole can be improved. Additionally, newly developed processes that combine conventional micro-milling with other technologies, which have great prospects in reducing the issues related to the physical process phenomena, are also introduced. Finally, the major applications of this versatile precision machining process are discussed with important insights into how the application range may be further broadened.

Development of an integrated PCA-SCA-ANOVA framework for assessing multi-factor effects on water flow: A case study of the Aral Sea

An integrated PCA-SCA-ANOVA framework (abbreviated as PSAF) is advanced to analyze the impacts of multiple factors on water-flow variation. PSAF incorporates techniques of principle component analysis (PCA), stepwise-cluster analysis (SCA), and analysis of variance (ANOVA) within a general framework. PSAF cannot only quantify the sensitivity of water flow to individual and interactive factors, but also simulate water flow effectively under different scenarios. A case study of the Aral Sea is conducted to demonstrate the effectiveness and practicability of PSAF. The Nash-Sutcliffe coefficients for calibration and validation are 0.96 and 0.84, respectively. Results reveal that the key impact factors that cause the variability of water flow from the Amu Darya into the Aral Sea are runoff in the upper reach (contributing 53%), agricultural water use (occupying 23%) and water storage in reservoirs (occupying 3%). Results also disclose that runoff in the upper reach and agricultural water use have obvious interaction; the high level of runoff in the upper reach can enhance the negative effects of agricultural water use on water flow. In the future, to recover the water flow from the Amu Darya into the Aral Sea to the level of that in the 1990s (about 8 km3), the decreasing rates of annual agricultural water use and water storage in reservoirs should be controlled at 1.0% and 0.5%, respectively. The findings are helpful for supporting water resources management and restoring the ecological environment of the Aral Sea.

Deformation behavior of a surface composition of materials with shape memory effect in the conditions of multi-factor impacts

The article presents the study results of the composite design of surface layers made of materials with shape memory effect (SME) by the method of layer-by-layer synthesis and their deformation behavior under conditions of multifactor effects. The use of multicomponent materials with TiNi-based SMEs as part of a layered surface composition made it possible to ensure an effective response of materials to external influences. We proposed an algorithm for designing a multifunctional composite coating for cyclic loading and corrosion-cavitation effects. We formulated recommendations on the choice of structure and architecture of a multifunctional composition. Based on the stress–strain analysis of the propeller blade with the multifunctional composite coating “steel J91171-Ni-TiNiZr-TiNiCo”, we demonstrated the expediency of surface composition made of SME materials in order to increase the functional reliability of the product. The results provided increased durability, increased wear and durability while reducing repair costs.

Cognitive impairment in patients with hematological malignancies at a long-term period after the transplantation of allogeneic hematopoietic stem cells

A comprehensive assessment of clinical, clinico-psychopathological, neurological, neuropsychological and instrumental examinations in a single study allows for a more detailed study of cognitive impairments in patients with CSC at a long-term period (12-15 months) after the transplantation of allogeneic hematopoietic stem cells.Purpose. Assessment of cognitive impairments in patients with hematological malignancies at a long-term period after the transplantation of allogeneic hematopoietic stem cells.Materials and methods. Clinical, psychopathological, clinical, psychological, neuropsychological, neurophysiological and neurovisual methods were used to examine 36 patients with various hematological malignancies in the period of 12-15 months after allo-HSCT. Statistical data analysis was performed using the methods of descriptive statistics, analysis of contingency tables and dispersive (with repeated measurements) analysis.Results and discussion. At a long-term period of the study (12-15 months), it was found that cognitive impairments are largely eliminated under the influence of a temporary factor, as well as the treatment of associated conditions (mental disorders, infectious complications, etc.). However, their level does not reach the normal (or close to them) values characteristics of the pre-transplant stage. Among the causes of this phenomenon, mention may be made of the organic lesions of the central nervous system, which are recorded during EEG, CEP, MRI / CT studies, and toxic encephalopathy due to exposure to chemotherapeutic and immunosuppressive drugs.Conclusion. The dynamics of cognitive impairments in general reflects the dynamics of the multifactor effects of various hazards accompanying the transplantation of allogeneic hematopoietic stem cells on the central nervous system. In this case, it can be stated with confidence that the allo-HSCT procedure in the overwhelming majority of cases does not lead to critical cognitive impairments.

Combinatory Multifactor Treatment Effects on Primary Nanofiber Oligodendrocyte Cultures.

Multiple sclerosis (MS) is a chronic inflammatory demyelinating and neurodegenerative disease of the central nervous system. Neurological deficits are attributed to inflammatory demyelination, which compromises axonal function and survival. These are mitigated in experimental models by rapid and often complete remyelination of affected axons, but in MS this endogenous repair mechanism frequently fails, leaving axons increasingly vulnerable to the detrimental effects of inflammatory and metabolic stress. Understanding the molecular basis of remyelination and remyelination failure is essential to develop improved therapies for this devastating disease. However, recent studies suggest that this is not due to a single dominant mechanism, but rather represents the biological outcome of multiple changes in the lesion microenvironment that combine to disrupt oligodendrocyte differentiation. This identifies a pressing need to develop technical platforms to investigate combinatory and/or synergistic effects of factors differentially expressed in MS lesions on oligodendrocyte proliferation and differentiation. Here we describe protocols using primary oligodendrocyte cultures from Bl6 mice on 384-well nanofiber plates to model changes affecting oligodendrogenesis and differentiation in the complex signaling environment associated with multiple sclerosis lesions. Using platelet-derived growth factor (PDGF–AA), fibroblast growth factor 2 (FGF2), bone morphogenetic protein 2 (BMP2) and bone morphogenetic protein 4 (BMP4) as representative targets, we demonstrate that we can assess their combinatory effects across a wide range of concentrations in a single experiment. This in vitro model is ideal for assessing the combinatory effects of changes in availability of multiple factors, thus more closely modelling the situation in vivo and furthering high-throughput screening possibilities.

Bubble evolution mechanism of pulse spark discharge in seawater

Underwater spark discharge could generate high-pressured bubble oscillations, which has broad application prospects in marine acoustic exploration and medical therapy. Much research has been focused on the first oscillation period, while little attention has been paid to the following periods and discharge efficiency. In this work, we studied the bubble evolution characteristics of three oscillations, as well as the multi-factor effects on radius, oscillation periods and energy efficiency. An experimental method is presented to control several influential factors to analyse their influences on bubble evolution and energy transformation. Notably, an image process algorithm is proposed to accurately describe the bubble evolution and the energy transformation efficiency. In addition, we analysed the jet flow formation during the first bubble growth and the non-uniformly distributed bubble dispersion. These results could provide references to the future optimization of bubble dynamic models and design of controllable acoustic sources.

Effect of additional axial tension on formability of equal curvature-diameter bending without mandrel for 0Cr18Ni9 stainless steel tube

The equal curvature-diameter (ECD; R0/D0 = 1.0; where R0 is the bending radius, and D0 is the outer diameter of tube) bending process without mandrel was regarded as the tube’s minimal bending condition. Compared with pure bending, this represented a very complex physical process with multifactor effects. The quality and forming limit of tube bending are affected by additional axial tension (AAT); therefore, in this study, the ECD bending process without mandrel for tubes was performed by combining the finite element (FE) method and experimental research. The effects of AAT on the bending formability, such as wall thickness variation, cross-section distortion, and springback, were investigated. The results showed that: (1) under a certain friction coefficient between the tube and pressure die, AAT was constant, the maximum wall thickness variation rate, the maximum cross-section minor axis variation rate, and the springback angle all increased with the increase of the bending angle; (2) under a certain bending angle, maximum wall thinning rate, maximum cross-section short axis variation rate, and springback angle were positively associated with the friction coefficient, while the wall thickening rate was negatively associated with it. These data implied that the maximum wall thinning rate, the maximum cross-section short axis variation rate, and the springback angle all increased, while the maximum wall thickening rate decreased with the increase of AAT; (3) when the friction coefficient was too small, AAT was too small. Although the degree of the wall thinning, cross-section distortion, and springback were relatively small, the degree of wall thickening was large and even wrinkled. On the contrary, when the friction coefficient was too large, AAT was too large. Although the degree of maximum wall thickening was relatively small, the degree of maximum wall thinning, maximum cross-section short axis variation rate, and the springback angle were large, and the tube’s surface was extensively scratched. When the friction coefficient was too large, it would have a negative impact on the comprehensive bending formability of tube. In conclusion, our study indicates that in order to ensure a tube’s comprehensive bending formability, AAT should be properly controlled by reducing the friction coefficient between the tube and pressure die.

Assessment of tissue-specific multifactor effects in environmental –omics studies of heterogeneous biological samples: Combining hyperspectral image information and chemometrics

The use of hyperspectral imaging techniques in biological studies has increased in the recent years. Hyperspectral images (HSI) provide chemical information and preserve the morphology and original structure of heterogeneous biological samples, which can be potentially useful in environmental –omics studies when effects due to several factors, e.g., contaminant exposure, phenotype,…, at a specific tissue level need to be investigated. Yet, no available strategies exist to exploit adequately this kind of information.This work offers a novel chemometric strategy to pass from the raw image information to useful knowledge in terms of statistical assessment of the multifactor effects of interest in –omic studies. To do so, unmixing of the hyperspectral image measurement is carried out to provide tissue-specific information. Afterwards, several specific ANOVA-Simultaneous Component Analysis (ASCA) models are generated to properly assess and interpret the diverse effect of the factors of interest on the spectral fingerprints of the different tissues characterized.The unmixing step is performed by Multivariate Curve Resolution-Alternating Least Squares (MCR-ALS) on multisets of biological images related to each studied condition and provides reliable HSI spectral signatures and related image maps for each specific tissue in the regions imaged. The variability associated with these signatures within a population is obtained through an MCR-based resampling step on representative pixel subsets of the images analyzed. All spectral fingerprints obtained for a particular tissue in the different conditions studied are used to obtain the related ASCA model that will help to assess the significance of the factors studied on the tissue and, if relevant, to describe the associated fingerprint modifications.The potential of the approach is assessed in a real case of study linked to the investigation of the effect of exposure time to chlorpyrifos-oxon (CPO) on ocular tissues of different phenotypes of zebrafish larvae from Raman HSI of eye cryosections. The study allowed the characterization of melanin, crystalline and internal eye tissue and the phenotype, exposure time and the interaction of the two factors were found to be significant in the changes found in all kind of tissues. Factor-related changes in the spectral fingerprint were described and interpreted per each kind of tissue characterized.

The effect of phosphorus addition, soil moisture, and plant type on soil nematode abundance and community composition

Environmental variables such as soil moisture and phosphorus (P) might influence above- and below-ground biodiversity. In this study, we investigated the rarely reported individual and interactive multifactor effects of soil moisture and phosphorus addition with the type of above-ground tree species (biological interactions) on the soil nematode community structure. We established a completely randomized experimental design with two plant types (N2-fixer and non-nitrogen fixer) and different combinations of water treatments and P additions (i.e., water with P addition, water only, drought with P addition, and drought only) in a greenhouse and investigated their effects on the soil chemical properties and nematode community. Soil samples were collected at the end of the experiment and were analyzed for soil moisture content (SM), available phosphorus (aP), nitrate nitrogen (NO3−–N), ammonium nitrogen (NH4+–N), dissolved organic carbon (DOC), dissolved organic nitrogen (DON), and nematode community. The following trophic groups were assigned to the nematodes: bacterivores (Ba), fungivores (Fu), omnivores–predators (Op), and plant parasites (PP). The channel index (CI), enrichment index (EI), maturity index (MI), genus richness (GR), and Simpson dominance (Ig) were adopted to indicate the indices of the nematode food web. Phosphorus addition and its interaction with water treatments had no statistically significant effects on the soil nematode community, but there were significant decreasing (p < 0.05) effects of P addition on the total density of nematodes of the N2-fixing tree under optimum water treatment. There were no significant interactive effects of P addition and water treatments on all the trophic groups, but plant type, water treatments, and their interactions significantly affected the density of most nematode trophic groups. The total nematode abundances of bacterivores, plant parasitic, omnivores, and enrichment index were significantly higher in the N2-fixers than in the non-nitrogen-fixing tree. Soil nematode abundance and community composition were more affected by the plant type than by the P addition and its interaction with water treatments. Drought exerted adverse effects on the total density of soil nematodes, the dominant genera, and the trophic groups. This study demonstrated that the rate of drought impact hinges more on the type of tree and that N2-fixing tree could still maintain the soil food web structure irrespective of the environmental changes.

Concrete durability under different circumstances based on multi-factor effects

Concrete durability has become a hot research field in civil engineering. Concrete structures suffer salt-erosion damage to different degrees in the semi-arid region of North China. The environmental condition is one of the important factors affecting the durability of concrete constructions. To realize fully the interaction between various environmental factors, this paper researched concrete durability in the salt environment under combined actions (immersing, freeze–thaw cycles, and wet–dry cycles). According to the laboratory test data, the concrete-durability degradation law under coupling-effect factors was investigated. The results show that concrete's compressive strength decreases with the increase of salt concentration and immersion time. No matter what the environmental conditions were, the compressive strength-loss ratio increased with the test time. The compressive strength-test results indicate that sodium sulfate has the strongest corrosive effect on concrete durability, followed by calcium chloride, with sodium chloride having the weakest corrosion. Compared with the other two environmental factors, the wet–dry cycle is the key factor affecting concrete durability. Therefore, in engineering practice, the influence of environment conditions on the strength and durability of concrete should be taken into full consideration, especially in the wet–dry environment with salt conditions.

Interrelationships of metal transfer factor under wastewater reuse and soil pollution

The transfer of heavy metals under soil pollution wastewater reuse was studied in a Greenhouse experiment using a randomized block design, including 6 treatments of heavy metals mixtures composed of Zn, Mn, Cd, Co, Cu, Cr, Ni, and Pb, where each metal was taking part in the mixture with 0, 10, 20, 30, 40, 50 mg/kg respectively, in four replications. The Beta vulgaris L (beet) was used as a test plant.It was found that the metal transfer factors were statistically significantly related to the: (i) DTPA extractable soil metals, (ii) the soil pollution level as assessed by the pollution indices, (iii) the soil pH, (iv) the beet dry matter yield and (v) the interactions between the heavy metals in the soil. It was concluded that the Transfer Factor is subjected to multifactor effects and its real nature is complex, and there is a strong need for further study for the understanding of its role in metal-plant relationships.

Effects of three global change drivers on terrestrial C:N:P stoichiometry: a global synthesis.

Over the last few decades, there has been an increasing number of controlled-manipulative experiments to investigate how plants and soils might respond to global change. These experiments typically examined the effects of each of three global change drivers [i.e., nitrogen (N) deposition, warming, and elevated CO2 ] on primary productivity and on the biogeochemistry of carbon (C), N, and phosphorus (P) across different terrestrial ecosystems. Here, we capitalize on this large amount of information by performing a comprehensive meta-analysis (>2000 case studies worldwide) to address how C:N:P stoichiometry of plants, soils, and soil microbial biomass might respond to individual vs. combined effects of the three global change drivers. Our results show that (i) individual effects of N addition and elevated CO2 on C:N:P stoichiometry are stronger than warming, (ii) combined effects of pairs of global change drivers (e.g., N addition+elevated CO2 , warming+elevated CO2 ) on C:N:P stoichiometry were generally weaker than the individual effects of each of these drivers, (iii) additive interactions (i.e., when combined effects are equal to or not significantly different from the sum of individual effects) were more common than synergistic or antagonistic interactions, (iv) C:N:P stoichiometry of soil and soil microbial biomass shows high homeostasis under global change manipulations, and (v) C:N:P responses to global change are strongly affected by ecosystem type, local climate, and experimental conditions. Our study is one of the first to compare individual vs. combined effects of the three global change drivers on terrestrial C:N:P ratios using a large set of data. To further improve our understanding of how ecosystems might respond to future global change, long-term ecosystem-scale studies testing multifactor effects on plants and soils are urgently required across different world regions.

Modeling of Electromagnetic Rail Launcher System Based on Multifactor Effects

In this paper, circuit simulation was chosen as the main methodology to analyze the characteristics of an electromagnetic (EM) rail launcher (or EM railgun) system, and a complex simulation model was proposed, which was not merely built on the static electrical parameters. Moreover, practical physical processes contributed to the system have also been taken into consideration and expressed as electrical parameters. Thus, the description of a relatively complex system could be realized by a comparatively simple manner, and the simulation result is more accurate and reliable compared with the traditional circuit simulation ones with the static electrical parameters. A circuit simulation model of an EM launch system based on PSpice software was built, in consideration of multifactor effects, such as current skin effect, contact pressure, and contact resistance on the contact surface of the armature and the barrel, velocity skin effect, friction drag, and temperature coefficient of electrical resistivity. Simulations were made based on the proposed model as well as the traditional one. Last but not the least, a comparison between the simulation results and the experimental ones was made to verify the accuracy and effectivity of the improved model.

Ecosystem-based assessment of a prawn fishery in coastal Kenya using ecological indicators

The study aimed to describe and assess indicators that can potentially contribute to the development of Ecosystem-based Approach to Fisheries Management (EAFM) of prawn stocks in the Malindi-Ungwana Bay, the most productive coastal ecosystem in Kenya. A comprehensive EAFM is required to holistically manage fisheries resources and their associated habitats. The study assessed ecological indicators based on objectives of harvest sustainability and biodiversity conservation. Analyses were performed on data sourced from the State Department of Fisheries, and research databases. Trends in historical landings (1985–2010) of penaeid shrimps from the Malindi-Ungwana Bay were analyzed using LOWESS. Number-size spectra analysis was used to assess the exploitation status of the shrimps, while biomass-trophic level spectra (BTLS) analysis was applied as a potential tool for analyzing multifactor effects on the bay. IndiSeas-based ecosystem indicators were used to assess impact of the prawn trawl fishery on biodiversity of the bay. Results indicate long-term series with two peaks (1997 and 2000) in historical landings of penaeid shrimps and a monotonous decline in catches during 2002–2010. Slopes of number-size spectra suggested increased fishing mortality with time (2008–2012), while patterns of intercepts indicated a general increase in fisheries productivity of the bay. BTLS analysis using demersal fish survey and fish by-catch data suggested reduced levels of biomass across trophic levels and a temporal decline in trophic levels of fish species caught, however, the short time span constrains robust conclusions from the BTLS analysis. Biodiversity and conservation based indicators (e.g. fish sizes, trophic levels and proportion of predators in catches) adopted from the IndiSeas program showed the Malindi-Ungwana Bay to be ecologically degraded. There is need to initiate long-term monitoring programs to strengthen temporal scale of analysis of the datasets and to support use of ecological indicators for resource management and development of an EAFM in data-poor WIO countries.

NEUTRALIZATION OF STEEL FIBER REINFORCED CONCRETE UNDER MULTIPLE INFLUENTIAL FACTORS

In this paper, the durability of steel fiber reinforced concrete/SFRC is tested under the combined effects of carbonization and acid rain erosion. Mass loss rate, splitting tensile strength loss rate, eroded thickness and neutralization depth were taken as evaluation index. Test results indicated that the concrete mass loss rate, splitting tensile strength loss rate, and eroded thickness of SFRC under the multi-combined effects of acid rain and carbonization are greater than that of SFRC affected by the acid rain; the neutralization depth of SFRC are larger under the multi-factor effects of acid rain and carbonization compared to the superposition of them. According to the analysis of combined effects, the carbonization and acid rain has almost equal contribution to the neutralization of concrete. Proper mixture of steel fiber can effectively inhibit the erosion of original concrete under the effect of acid rain and reduce the neutralization depth. According to the varied mixing proportions in the test, the SFRC with the steel fiber mixing proportions of 1.5% has the best durability.

Multi-factor climate change effects on insect herbivore performance

performance Christoph Scherber, David J. Gladbach, Karen Stevnbak, Rune Juelsborg Karsten, Inger Kappel Schmidt, Anders Michelsen, Kristian Rost Albert, Klaus Steenberg Larsen, Teis Norgaard Mikkelsen, Claus Beier & Soren Christensen Agroecology, Department of Crop Science, Georg-August-University of G€ ottingen, Grisebachstrasse 6, D-37077 G€ ottingen, Germany Terrestrial Ecology, Department of Biology, University of Copenhagen, Universitetsparken 15, 2100 Kobenhavn O, Denmark Forest and Landscape, University of Copenhagen, Rolighedsvej 23, 1958 Frederiksberg C, Denmark Department of Geosciences and Natural Resource Management, University of Copenhagen, Rolighedsvej 23, 1958 Frederiksberg, Denmark Department of Chemical and Biochemical Engineering, Technical University of Denmark, DTU, DK-2800 Kgs. Lyngby, Denmark