Numerical Variation Research Articles

Strain localization and deformation behavior in ferrite-pearlite steel unraveled by high-resolution in-situ testing integrated with crystal plasticity simulations

This paper attempts to study the microstructural stress-strain evolution and strain localization in the ferrite-pearlite steel by high-resolution experimental-numerical integrated testing. Ferrite crystal orientations measured by electron backscatter diffraction (EBSD) were mapped onto precise scanning electron microscopy (SEM) micrographs of ferrite and cementite lamellar morphologies. Furthermore, in-situ SEM tensile testing was employed to map strains during the deformation using digital image correlation (DIC) at high spatial resolutions. Finally, spectral solver-based crystal plasticity (CP) simulations loaded by the local SEM-DIC boundary conditions were performed and compared to the experimental data. Crucially, all microstructure data was carefully aligned, and strains were filtered to the same spatial resolution, measured to be as small as ~75 nm. This integrated methodology yields new insights in the high degree of plastic strain partitioning between ferrite grains and pearlite colonies, and ferrite and cementite lamellae inside pearlite. One-to-one experimental-numerical comparison augmented with the numerical variation of the ferrite constitutive model, pearlite interlamellar spacing, and lamellar orientation reveals how the ferrite-cementite strain partitioning and the onset of strain localization depend on the morphology and distribution of ferrite grains and pearlite colonies. Importantly, this comparison showcases the limitations of state-of-the-art simulations in their capability to predict specific mechanisms and correct degrees of strain heterogeneity.

Dynamics of unsteady reactive flow of viscous nanomaterial subject to Ohmic heating, heat source and viscous dissipation

Owing to the improved thermophysical properties of nano-materials, the nanofluid convey novel applications in industries, engineering as well as bio-medicals. With high efficiency performances, the nanoparticles include applications in various cooling and heating systems, energy production, aerospace engineering, thermal extrusion, bio-medical applications like treatment of diseases, brain tumour, surgical applications and many more. Moreover, the magneto-nanofluids have the characteristics in the flow of blood in the human artery. The current analysis deals with the free convective unsteady flow of viscous nanofluid subject to the magnetic force over a vertical plate in presence of porous space. The heat transfer phenomenon is accessed by utilizing the additional features like Joule heating, viscous dissipation and absorption coefficients. In addition to the volume fraction of the nanofluid, the effect of the chemical reaction is also introduced. The solution procedure for the modified time-dependent boundary value problem is performed by using the code in-build MATLAB namely Built-in-Shooting method. The change in velocity, temperature and concentration of nano-materials is examined through various graphs. The physical consequences of flow parameters like porosity parameter K p 1 ⩽ K p ⩽ 3 , thermal Grashoff number Gr 1 ⩽ G r ⩽ 3 , solutal Grashoff number Gc 1 ⩽ G c ⩽ 3 , magnetic field parameter M 1 ⩽ M ⩽ 3 , thermal radiation parameter Nr 0.1 ⩽ N r ⩽ 1 , radiation absorption parameter Q 0 ⩽ Q ⩽ 0.5 , Prandtl number Pr 2 ⩽ Pr ⩽ 21 , Eckert number Ec 0 ⩽ E c ⩽ 0.4 , heat source S - 0.2 ⩽ S ⩽ 0.2 , chemical reaction parameter Kc 1 ⩽ K c ⩽ 4 , nanoparticles volume fraction ϕ 0.0 ⩽ ϕ ⩽ 0.1 , Lewis number Le 1 ⩽ L e ⩽ 10 on velocity, temperature and concentration distributions is graphically analyzed. The results show that skin friction coefficients decline with buoyant forces. A lower numerical variation in Nusselt number is resulted with heat source parameter. Moreover, a sharp fall in nanofluid concentration is noticed with increment of chemical reactants and Lewis number.

Parametric study of plate heat exchanger for eventual use in a solar pasteurization process designed for small milk collection centers in Tunisia

In this study, we propose to design a solar pasteurization system for small productions collection centers. This system allows minimizing the amount of rejected milk during transport process from the producer to the factory. It consists of solar water collector system, plate hate exchangers (PHE) and an absorption chiller. A numerical study is conducted to evaluate the behavior of the mass and heat transfer through the PHE. An experimental study is performed to determine the plate heat exchanger thermal performances. A comparison between the measured and numerical variation of different fluids temperatures is also conducted. Principal numerical results point out that the turbulence depends on the angle of plate corrugations inclination (β). Experimental results show that for fixed cold fluid flow, the PHE global heat transfer coefficient increases with the hot fluid flow. Its thermal efficiency can reach 80% for a hot water inlet temperature of 80 °C and for a flow rate of 386 l.h−1.

The crystalline waters of the Bodoquena Plateau revealed Hypostomus froehlichi (Siluriformes: Loricariidae), a new armored catfish from the rio Paraguay basin in Brazil.

The menaced and poorly-known waters of the Bodoquena Plateau revealed a new resident, the stunning Hypostomus froehlichi sp. n., a large-sized armored catfish, which is finally described after more than twenty years since its discovery. The Bodoquena Plateau is drained by the rio Paraguay basin, and is located in the state of Mato Grosso do Sul, Brazil. The new species differs from its congeners on the Bodoquena crystalline waters by having teeth with morphological and numerical variation in adult specimens. There is a continuous range of specimens having about 20 thick and worn teeth to specimens having about 50 thin teeth with intact crowns and lanceolate main cusps. Additional diagnostic characters are: dentaries angled more than 90 degrees, dark blotches, one plate bordering supraoccipital, moderate keel along dorsal series of plates, usually two rows of blotches per interradial membrane on dorsal, pectoral and ventral fins, and by attaining comparatively large size. Hypostomus froehlichi seems to be endemic to the area of the Bodoquena Plateau, in rivers draining to the rio Miranda. The description of the new species reveals a potential conservation flagship species as it is one of the most seen and documented fish by visitors and divers in the clear waters from the touristic, though menaced, Bonito region in Brazil.

A New Variant B Chromosome in Auchenipteridae: The Role of (GATA)n and (TTAGGG)n Sequences in Understanding the Evolution of Supernumeraries in Trachelyopterus

Basic and molecular cytogenetic techniques were carried out in 3 Neotropical region populations of catfishes, two of Trachelyopterus galeatus (one from the marshlands of Paraguay River basin and another from Lago Catalão, Amazon River basin) and one of Trachelyopterus porosus, a sympatric population to T. galeatus from the Amazon River basin. This study aimed to describe and understand the structure and evolution of Trachelyopterus B chromosomes, mainly through physical mapping of repetitive elements. A diploid number of 58 chromosomes was found for all individuals, as well as the presence of B chromosomes. For T. porosus this is the first report of a supernumerary. The sympatric species of T. galeatus and T. porosus from Amazon River had 1–3 B chromosomes and T. galeatus from Paraguay River had 1–2 B chromosomes, all of them showed intra- and interindividual numerical variation. Two females of T. porosus exhibited a new variant B chromosome (B2), previously not seen in Auchenipteridae, which might have originated from B1 chromosomes. All B chromosomes were entirely heterochromatic. In contrast to all complement A and B2 chromosomes, in which the telomeric sequences were found in the telomeric regions, B1 chromosomes of all populations were totally marked by (TTAGGG)_n probes. (GATA)_n sequence sites were found through all complement A chromosomes, but B1 and B2 chromosomes exhibited only a clustered block in one of the chromosome arms. The most frequent B chromosomes (B1) in all populations/species, including those previously studied in Auchenipteridae catfishes, share the following characteristics: totally heterochromatic, small, metacentric, with accumulation of repetitive (TTAGGG)_n sequences, and a low number of (GATA)_n copies, which might suggest a common ancient origin in Trachelyopterus species/populations.

First chromosomal analysis in Deinopidae (Araneae) reveals Sex Chromosome System X1X2X3X4, B chromosomes and polymorphism for centric fusion

Here we present the first cytogentic study concerning Deinopidae and their controversial phylogenetic position. This study karyologically analyzed one population of Deinopis biaculeata Simon, 1906 and five populations of Deinopis plurituberculata Mello-Leitão, 1925. The majority of specimens of D. plurituberculata exhibited 2n♂ = 40 and 2n♀ = 44 telocentric chromosomes (however some of them showed B chromosomes, belongs to Aquidauana and Botucatu population). The Deinopis biaculeata and D. plurituberculata meiosis of males showed 18 autosomal bivalents + X1X2X3X4, n = 22 and n = 18, a rare sex chromosome system (SCS) in spiders. Some individuals of D. plurituberculata from the Campo Grande population exhibited 2n♂ = 39 and 2n♀ = 43, with a metacentric chromosome (heterozygotes for centric fusion). The D. plurituberculata males with the rearrangement exhibit diplotenes with 16 autosomal bivalents + 1 autosomal trivalent + X1X2X3X4 and metaphases II with n = 22 (18 telocentric autosomes + X1X2X3X4), n = 21 (16 telocentric autosomes + a metacentric autosome + X1X2X3X4), n = 18 (18 telocentric autosomes) and n = 17 (16 telocentric autosomes + a metacentric autosome). The Ag-NORs (silver impregnation) are terminally located in a pair, coinciding with secondary constriction, which is the most common configuration for Araneae. The relatively high diploid number in Deinopis corroborates phylogenies that place it in a basal position among Entelegynes, in the UDOH grade (Uloboridae, Deinopidae, Oecobiidae and Hersiliidae). Centric fusion in only one population of D. plurituberculata suggests low dispersion capacity of this species and an absence of homozygotes for fusion suggests their low viability or a need to increase the population sampling of D. plurituberculata exhibiting the rearrangement. B chromosomes were detected in D. plurituberculata, with interpopulacional, intrapopulacional and intraindividual numerical variation, with cells presenting 0 - 3 and 0 - 6 B chromosomes in populations of Aquidauana and Botucatu, respectively.

Morphological and numerical variation patterns of floral organs in two species of Eranthis

There is wide diversity in flower structure and pattern in nature. The number and morphological variation of flower organs in Eranthis of the family Ranunculaceae is high, but the pattern of flower structure variation in this genus is unclear. In this study, the morphological and numerical variation in organs of Eranthis stellata Maxim. and Eranthis lobulata W. T. Wang were observed with stereomicroscopy and scanning electron microscopy, and the patterns of variation were summarized statistically. The results showed the following: (1) The structural patterns of the two species of Eranthis were not stable. There were 232 flower structural patterns among 300 individuals of E. stellata and 55 among 100 individuals of E. lobulata. The number of floral organs in E. lobulata was significantly less than that in E. stellata. (2) The morphological variation in flower organs in Eranthis mainly occurred in petals, especially in the upper lip, pseudonectaries and lower lip, e.g., the number of lobes, and pseudonectaries and inconsistency in the upper lip edge. (3) The coefficient of variation (CV) of flower organs was greater than 20%, with some values close to 40%, which indicates that the number of floral organs of the two species differ substantially, and that the number of floral organs was extremely unstable. The range in stamen number was the largest while that in sepal number was the smallest, and this fluctuation might be caused by the spiral phyllotaxis of floral organs.

High chromosomal evolutionary dynamics in sleeper gobies (Eleotridae) and notes on disruptive biological factors in Gobiiformes karyotypes (Osteichthyes, Teleostei).

The order Gobiiformes is made up of more than 2200 species, representing one of the most diverse groups among teleost fishes. The biological causes for the tachytelic karyotype evolution of the gobies have not yet been fully studied. Here we expanded cytogenetic data for the Eleotridae family, analyzing the neotropical species Dormitator maculatus, Eleotris pisonis, Erotelis smaragdus, and Guavina guavina. In addition, a meta-analytical approach was followed for elucidating the karyotype diversification versus biological aspects (habitat and egg type) of the Gobiiformes. The species E. smaragdus and E. pisonis present 2n = 46 acrocentric chromosomes (NF = 46), D. maculatus 2n = 46 (36sm + 4st + 6a; NF = 86), and G. guavina, the most divergent karyotype, with 2n = 52 acrocentric chromosomes (NF = 52). Besides numeric and structural diversification in the karyotypes, the mapping of rDNAs and microsatellites also showed noticeable numerical and positional variation, supporting the high chromosomal evolutionary dynamism of these species. In Gobiiformes, karyotype patterns which are more divergent from the basal karyotype (2n = 46a) are associated with characteristics less effective to dispersion, such as the benthic habit. These adaptive characteristics, connected with the organization of the repetitive DNA content in the chromosomes, likely play a synergistic role in the remarkable karyotype diversification of this group.

Three-dimensional morphological changes of potato slices during the drying process

Hot air drying is a common method for drying potato slices. In this paper, the three-dimensional (3D) morphological changes incurred during hot air drying of potato slices were investigated. The effect of drying on the thickness and diameter of potato slices was of special interest. The results showed that the potato slices underwent stages of regular warping, collapse, and curling during the drying process. After classifying the numerical variation in characteristics into the standard deviation in mean height (SDMH) and the rate of change in mean height (RCMH) of potato slices, the RCMH was selected to describe the 3D morphological changes in the potato drying process. A critical point and a termination point for RCMH of potato slices in the drying process were observed. Samples varied widely after the critical point was reached. A logarithmic function model was used to assess differences in the RCMH at the critical point and the termination point. The R-squared (R2) value of 0.9 suggested a strong correlation between the parameters of the experiment and changes in slice thickness and diameter. The model proposed in this paper could accurately characterize the late-stage changes in potato slice qualities during hot air drying of potato slices.

Numerical simulation and experiment on generation dynamics of a Ho3+-doped fiber laser with an intracavity Mach–Zehnder modulator

We present the numerical simulation and experimental results on generation dynamics of an all-fiber holmium laser with an intracavity modulator based on a Mach–Zehnder interferometer. The experimental data were compared with numerical simulation results in a wide range of parameters. An explanation for the observed increase in the pulse repetition rate from 5.8 to 11.6 kHz, as well as the transition to the chaotic pulsations mode, was given. A numerical variation of the unknown or difficult-to-measure losses in the experiment was carried out. The obtained set of parameters allowed us to implement the correct numerical optimization of an active medium and cavity. As a result, the peak powers of about 9.5 and 13 W were obtained during the experiments, as well as in the numerical simulation.

A Study of the Simulation and Analysis of the Flow Field of Natural Convection for a Container House

Natural disasters, such as earthquakes, windstorms, and tsunamis, can occur all over the world, and disasters caused by human factors, such as civil wars, are also a source of major disturbance. The temporary rehousing of the population is a major problem when disasters occur. The installation of the combination house is time consuming, and tents cannot be used in the event of strong rain and wind; therefore, the container house is the most effective way of solving the rehousing problem. Natural ventilation is the main factor affecting the indoor air quality, thermal comfort, and health inside a container house, and solar radiation heat can also affect temperature changes inside. The air flow field inside a dwelling is very complex, and its flow mode is affected by inlet wind speed, inlet temperature, solar radiation heat, and the size of doors and windows, etc. In this paper, the influence of natural ventilation on the ventilation inside container houses is analyzed. Assuming that there is complex fluid motion in the activity space of the container house, it is not easy to use conventional methods to predict the flow rate. Based on the correlation analysis motion between the corresponding internal flow rates, the calculation and application method of flow is simplified from the results of the wind speed coefficient obtained previously. In addition, an analysis of flow characteristics in the container house is made; simulation analysis in the container house is made by carrying out the numerical analysis of several factors, including velocity field and temperature field. The variation state of the temperature of the environment and a numerical variation of the three-dimensional space are obtained by numerical calculation; the standard k-ε turbulence model is adopted to describe the turbulence phenomena of the fluid, and the mathematical model matched by B-spline surface is used for data analysis through the surface algorithm in order to deal with complex simulation data. The research results show that, regarding the influence of natural ventilation on container houses, the ideal relative position of openings includes the combination of asymmetric windows, followed by the central positioning of the door. The four-opening configurations, where better natural ventilation performance can be achieved, are located at different diagonal positions. The average flow velocity vector form, velocity amplitude, radiation temperature distribution, and the effect of the air volume coefficient of temperature change are analyzed. The research results show that the design of container houses can meet the requirements of air flow, such as the energy consumed by the thermal comfort space. Measurements taken over time and algorithms can also check the residents’ indoor natural ventilation and provide health care by the use of various sensors.

Perfil das internações por encefalite viral no Brasil em 2018 por unidade da federação, sexo e faixa etária

Introdução: A encefalite viral é uma condição com altas taxas de morbimortalidade, e um melhor entendimento de sua epidemiologia pode colaborar para a construção de estratégias de prevenção e controle. Diante disso, este estudo se propôs a traçar um perfil epidemiológico para a encefalite viral no Brasil no ano de 2018 a partir de dados de internações hospitalares no Sistema Único de Saúde (SUS). Métodos: Estudo ecológico de análise espacial. Os dados estudados foram relativos às internações hospitalares por encefalite viral no SUS em 2018, estratificadas por unidade da federação (UF), sexo e faixa etária. A distribuição geográfica foi abordada exploratoriamente, já as variáveis sexo e faixa etária foram abordadas analiticamente. Resultados: Foram registradas 2075 internações, com taxa de 0,99/105 habitantes. As taxas para cada UF foram representadas a partir de um mapa colorimétrico, enquanto as taxas para cada sexo e faixa etária foram representadas em uma tabela comparativa univariada. Discussão: Observou-se ampla variação numérica das taxas de internação dentre as UF, sendo Pernambuco o estado com maior incidência (4,13/105 habitantes) e Paraíba o estado com menor (0,29/105 habitantes). Foi constatada associação significativa com risco de internação hospitalar por encefalite viral para o sexo masculino e para as faixas etárias de 1 a 4 anos (RR: 3,28) e menores de 1 ano (RR: 6,02). Conclusão: UF, gênero e faixa etária foram determinantes importantes da taxa de internação hospitalar por encefalite viral. Todavia, carecem de estudos atuais no Brasil e no mundo para a melhor caracterização da epidemiologia da encefalite viral.

Analysis of the performance of a low-power atmospheric burner for gas appliances for households and their impact on the emission and stability of the burner

The paper presents results of theoretical numerical research dealing with CO and NOx emission performed in the process of optimization of the performance of low-power atmospheric burners. The theoretical part of this paper, whose main goals were better understanding of the complex issues of methodology and establishment of performance prediction and optimization of low-power atmospheric gas burner included numerical variation of independent parameters, such as burner geometry, the coefficients of primary and secondary air and different gaseous fuels including biogas. The findings of theoretically obtained performance prediction and optimization of atmospheric burners were experimentally investigated in purpose built test rigs for a number of variable parameters. The obtained results fully justified the proposed models of performance prediction and burner optimization.

Population dynamic of <i>Diclidophlebia irvingiae</i>, Burckhardt et al. (Hemiptera: Psylloidea), psyllid pest of <i>Irvingia gabonensis</i> Baill (Irvingiaceae, Rutales) in Bamenda, North-West region of Cameroon

Diclidophlebia irvingiae is a sap-sucking insect of Irvingia gabonensis inducing important damage to its host plant which has medicinal and nutritional importance in Africa particularly in Cameroon. The aim of the survey was to study numerical variation of the pest during the year and impact of biotic and abiotic factors on numerical variation. The study was carried in Bamenda from March 2018 to March 2019 where larvae and adults of D. irvingiae were collected monthly. The study permitted us to record 3290 individuals 1341 males, 1396 females and 553 larvae. Population fluctuation of the pest during the year showed five periods of individual outbreak corresponding to the generation number of the pest. As most tropical and sub-tropical psyllid species D. irvingiae is a multivoltine species with five annual generations. The outbreak periods depend principally on the phenology of host plant. The statistical test showed that the numerical individual variation of D. irvingiae is not directly related to climatic factors because they do not show significant probability.Keywords: Impact, Biotic, Abiotic, Factors, Insect, Faunistic.

Transforming kinks into compactons in the [formula omitted]-sigma model

In this work, we investigate the solutions of vortices in the O(3)-sigma model with the gauge field governed by the Chern–Simons term and subject to a hyperbolic self-dual potential. We show that this model admits both topological and nontopological soliton solutions. Employing numerical analysis, we realize that the topological solutions of the model can be transformed into compacton-like solutions. On the other hand, after modifying the model by the introduction of a dielectric constant, an exciting feature appears; namely, the nontopological solutions can be transformed into kink-like solutions through the numerical variation of the dielectric constant. Furthermore, we discuss the degeneracy for the topological solitons in a given sector. Finally, we present the numerical solutions of the first model.

Correlated energy uncertainties in reaction rate calculations

Context. Monte Carlo methods can be used to evaluate the uncertainty of a reaction rate that arises from many uncertain nuclear inputs. However, until now no attempt has been made to find the effect of correlated energy uncertainties in input resonance parameters. Aims. Our goal is to investigate the impact of correlated resonance energy uncertainties on reaction rates. Methods. Using a combination of numerical and Monte Carlo variation of resonance energies, the effect of correlations are investigated. Five reactions are considered: two fictional, illustrative cases and three reactions whose rates are of current interest. Results. The effect of correlations in resonance energies depends on the specific reaction cross section and temperatures considered. When several resonances contribute equally to a reaction rate, and when they are located on either side of the Gamow peak, correlations between their energies dilute their effect on reaction rate uncertainties. If they are both located above or below the maximum of the Gamow peak, however, correlations between their resonance energies can increase the reaction rate uncertainties. This effect can be hard to predict for complex reactions with wide and narrow resonances contributing to the reaction rate.

Impact of Varying High- and Low-Pressure Turbine Purge Flows on a Turbine Center Frame and Low-Pressure Turbine System

Abstract This paper presents the experimental and numerical evaluation and comparison of the different flow fields downstream of a turbine center frame duct and a low-pressure turbine (LPT) stage, generated by varying the inlet flow conditions to the turbine center frame (TCF) duct. The measurements were carried out in an engine-representative two-stage two-spool test turbine facility at the Institute for Thermal Turbomachinery and Machine Dynamics at Graz University of Technology. The rig consists of a high-pressure turbine (HPT) and a LPT turbine stage, connected via a TCF with non-turning struts. Four individual high-pressure turbine purge flowrates and two low-pressure turbine purge flowrates were varied to achieve different engine-relevant TCF and LPT inlet flow conditions. The experimental data were acquired by means of five-hole-probe (5HP) area traverses upstream and downstream of the TCF and downstream of the LPT. A steady Reynolds-averaged Navier–Stokes (RANS) simulation taking all purge flows in account was used for comparison, and additional insights are gained from a numerical variation of the HPT and LPT purge flowrates. The focus of this study is on the impact of the variations in TCF inlet conditions on the secondary flow generation through the TCF duct and the carryover effects on the exit flow field and performance of the LPT stage. Existing work is limited by either investigating multistage LPT configurations with generally very few measurements behind the first stage or by not including relevant HPT secondary flow structures in setting up the LPT inflow conditions. This work addresses both of these shortcomings and presents new insight into the TCF and LPT aerodynamic behavior at varying the HPT and LPT purge flows. The results demonstrate the importance of the HPT flow structures and their evolution through the TCF duct for setting up the LPT inflow conditions and ultimately for assessing the performance of the first LPT stage.

Lyriform vibration receptors in the web‐building spider, Nephila clavata (Araneidae: Araneae: Arachnida)

AbstractVibration receptors appear to be more necessary for web‐building spiders, but most knowledge of arachnid lyriform organs comes from the study of wandering spiders affected by ground vibrations. Here, we examined the fine structural aspects of the lyriform organs in the web‐building spider Nephila clavata using field emission scanning electron microscopy (FESEM) to fill the gap. The lyriform organ is found in all appendages, including the femur, patella, tibia, and metatarsal segments. A number of slit receptors of various sizes are distributed in the parallel orientation of the cuticle along the long axis. According to its fine structural characteristics, all lyriform organs of this spider are classified as a compound type with multiple cuticular slits. However, the number of cuticular slits per each lyriform organ varies considerably from a minimum of three to a maximum of 17. A total 35 pairs of lyriform organs were counted from an adult female spider. Except for small numerical variation in the 4th appendage, the distribution is remarkably constant within each appendage. Comparing the total number of cuticular slits per each appendage, the 3rd appendage has the highest number (85), but the 4th appendage shows the least number (63). Based on the total number of cuticular slits per leg segment, the patella segment seems to be the most sensitive to vibration reception in this orb‐web spider.

Population dynamics of Cacopsylla sp. (Hemiptera: Psylloidea: Psyllidae), pest insect of Prunus africana (Rosaceae), medicinal plant species in Cameroon

Prunus africana is threatened in Cameroon by xylophagous and sap-sucking pest as Cacopsylla sp. This last causes deformations of the young leaves and buds and the plant end up losing all its leaves. Effective control of phytophagous pests requires a thorough understanding of their seasonal population dynamics. The objective of this work carried out on 150 young plants of P. africana in the nursery in Dschang, was to study the population dynamics of Cacopsylla sp. and the impact of climatic factors on the population. From January 2006 to December 2007, monthly collections of larvae, males and females of Cacopsylla sp. were carried out. The results showed, in 2006, three peaks (March, August and December) and two peaks in 2007 (March and August) with larvae. The fluctuation of males' population showed five peaks with two peaks in 2006 (March and December) and three peaks in 2007 (March, June and December) while in females' population, four peaks with two peaks in 2006 (March and December) and two peaks in 2007 (March and November). The annual numerical variation of Cacopsylla sp. individual is statistically correlated with variation of precipitations and the insolation. The precipitations have a negative effect on the numerical variation of males (r=-0.430, p<0.0360) and females (r=-0,434, p<0.0336) of Cacopsylla sp. The insolation has a positive effect on the numerical variation of males (r=0.732, p<0.0000002), females (r=0.653, p<0.000523) and the total individuals (r=0.601, p<0.00197) of Cacopsylla sp. With the larvae, the correlation was negative and non-significant. This work showed that March and December were better indicated to engage the fight against Cacopsylla sp. in Dschang.

Assessment of priorities in critical material recovery from Waste Electrical and Electronic Equipment

A major problem in developing environmental management systems for assessing recovery priorities for high added-value materials such as critical metals from wastes is that the input data required are contained in a variety of databases compiled for different purposes with different levels of content and accuracy. To deal with decision-making priorities for environmental issues where uncertainties and inconsistencies are inherent in input data sources a Multi-Criteria Decision Analysis (MCDA) approach using an Analytic Hierarchy Process (AHP) to determine weights and fuzzy numbers to account for input data uncertainties is developed and is illustrated for determination of critical metal recovery priorities from Waste Electrical and Electronic Equipment (WEEE) in Europe. A spreadsheet programme with many user-friendly input and output features is developed to aid data-handling and the calculations required in the MCDA approach. Where data uncertainties exist, weighted input parameters for the critical metals are determined by an absolute judgement panel of key stakeholders and include data on: recovery potential, geographical supply concentration and stability, end use substitution, future metal demand and economic importance in key industrial sectors. Sensitivity analyses can be carried out on results of recovery priority outputs by simple numerical variation of input parameters and/or by the use of specialist input decision panels representing stakeholder groups with differing priorities, and the results suggest that recovery priorities in the European situation should concentrate on gallium, indium and germanium. The spreadsheet-MCDA program set up in developing the methodology for criticality has wide general application in environmental decision-making analysis particularly where uncertainties exist in the input data required.