A study on the effects of lime on the mechanical properties and behaviour of London clay

Lime is commonly used as a stabiliser to improve the engineering properties of soils in particular for roads and pavement foundation. Despite the popularity of the technique, only a limited amount of existing experimental data for lime treated soils from advanced testing is available, in part due to the length of the tests. As lime stabilisation is increasingly used for other engineering applications (e.g. embankments, railway layers, canal linings, earth dams, buildings...etc), advanced testing to describe the mechanical behaviour of the treated soils is required. In this research a comprehensive experimental program was carried out to investigate the engineering properties and behaviour of a lime treated high plasticity clay (London Clay). A number of Unconsolidated Undrained (UU), Consolidated Drained (CD) and Consolidated Undrained (CU) triaxial tests were performed to identify the effect of lime dosage, compaction water content and curing time on the shear strength parameters, stressstrain behaviour, volumetric response and dilation of the treated soil. Moreover the study focused on understanding the mineralogical and physicochemical transformations occurring during the curing stage. Based on a number of additional tests (XRD analysis, pH measurement and other chemical testing) they provided a useful reference for the interpretation of the triaxial test results; in order to support hypotheses made on the evolution of the chemical reactions and the development of cementation bonds. Results from CD tests showed that yield, peak, and ultimate strength were greatly improved by an increase in lime content. London Clay samples treated with lime showed a considerable increase in peak stress ratio ( ) peak q / , particularly at lime addition beyond p' the initial consumption of lime (ICL). An increase in the angle of shearing resistance and cohesion intercept with increasing lime content was observed consistently. The stress– strain behaviour of treated London Clay was observed to be nonlinear with a contractive– dilative response. This response is found to be strongly influenced by lime content and the curing period. An increase in dilation with lime amount as well as a progressive suppression in the dilation by the effective stress increase was also observed. A Critical State Soil Mechanics (CSSM) framework was used to interpret the results. Lime addition, curing time and compaction water content were observed to have an impact on the critical iv state parameters in the compression plane (v − p'). However, the overall critical state line (CSL) in the stress space (q − p') of lime treated London Clay appears to be almost parallel to untreated London Clay CSL at the same M value, but lying above the untreated CSL with a cohesion intercept. Moreover, the domain where the untreated soil subsists was observed to expand with lime addition and further enlarge with an increase in the lime content. These features can be further explored by deriving a suitable constitutive model for predicting the mechanical behaviour of lime treated soils

Automatic supervision of Pv systems and degradation analysis of thin film PV modules

Monitoring and regular performance analysis of Grid-Connected Photovoltaic (GCPV) systems are of primal importance in order to ensure an optimal energy harvesting and reliable power production at competitive costs. Main faults in GCPV systems are caused by short-circuits or open-circuits in PV modules, inverter disconnections, PV module degradation and the presence of shadows on the PV array plane. Detecting these faults can minimize generated losses by reducing the time in which the PV system is working below its optimum point of power generation. In addition, the degradation of Tin Film PV (TFPV) modules under outdoor exposure is still not fully understood and is currently object of research. A better understanding on this topic would be important for selecting the best PV technology for the appropriate climatic condition and for improving the reliability and performance of PV systems. Simulations play a crucial role in both outdoor behaviour forecasting and automatic fault detection of GCPV systems. Two PV module/array models have been used in the present thesis in order to simulate the outputs of GCPV systems of different topologies and solar cell technologies, as well as in the fault detection procedure. Moreover, five different algorithms were used for estimating the unknown parameters of both PV models in order to see how these estimated parameters affect their accuracy in reproducing the outdoor behaviour of three GCPV systems. The obtained results show that the metaheuristic algorithms are more efficient than the Levenberg-Marquardt algorithm (LMA) especially in bad weather conditions and both PV models perform well when used in the automatic fault detection procedure. A new approach for automatic supervision and remote fault detection of GCPV systems by means of OPC technology-based monitoring is presented in this thesis. The fault detection procedure used for the diagnosis of GCPV systems is based on the analysis of the current and voltage indicators evaluated also from monitored data and expected values of current and voltage obtained from the model of the PV generator. Three GCPV systems having different sizes, topologies and cell technologies have been used for the experimental validation of the proposed fault detection method. The analysis of current and voltage indicators has demonstrated effectiveness in the detection of most probable faults occurred in the PV arrays in real time. Furthermore, obtained results show that the combination of OPC monitoring along with the proposed fault detection procedure is a robust tool which can be very useful in the field of remote supervision and diagnosis of GCPV systems. Finally, the study of degradation issues of TFPV modules corresponding to four technologies: a-Si:H, a-Si:H/µc-Si:H, CIS and CdTe, deployed under outdoor conditions for long term exposure is also addressed in the present thesis. The impact of the degradation on the output power of the PV modules is analysed, in order to determine their annual degradation rate and their stabilization period. The degradation rate is obtained through a procedure based on the evolution of the module effective peak power over time. The stabilization period is evaluated by means of two methods: the evolution of DC-output power of the PV module, and the power-irradiance technique. The obtained results show that the CIS PV module is the most stable compared to the other technologies, when deployed under Continental-Mediterranean Climate. The a-Si:H and a-Si:H/µc-Si:H PV modules also perform quite well, showing degradation rates and stabilization periods similar to the expectations. The CdTe module shows poor performances, with the highest degradation rate, and long stabilization period of 32 months. Lastly, the parameter extraction technique has been also applied to analyse the evolution of model parameters for a-Si:H and a-Si:H/µc-Si:H arrays working in outdoor conditions for long term exposure.Los fallos principales en los SFCR son causados por cortocircuitos o circuitos abiertos en módulos fotovoltaicos, desconexiones de inversores, degradación de módulos fotovoltaicos y presencia de sombras en el plano del generador fotovoltaico. La detección de estos fallos puede minimizar las pérdidas generadas al reducir el tiempo en que el sistema fotovoltaico está funcionando por debajo de su punto óptimo de generación de energía. Por otro lado, la degradación de los módulos fotovoltaicos de capa delgada (TFPV) en condiciones reales de trabajo sigue siendo actualmente objeto de investigación. Una mejor comprensión de este tema es importante para seleccionar la tecnología fotovoltaica más adecuada para cada condición climática específica y mejorar así tanto la fiabilidad como el rendimiento de los sistemas fotovoltaicos. Las simulaciones desempeñan un papel crucial tanto en el pronóstico del comportamiento real como en la detección automática de fallos en los SFCR. En la presente tesis se han utilizado dos modelos de módulos fotovoltaicos para simular las salidas de los sistemas de diferentes topologías y tecnologías de células solares, así como en el procedimiento de detección de fallos. Se han utilizado cinco algoritmos diferentes para estimar los parámetros de ambos modelos con el fin de ver cómo estos parámetros afectan a su precisión en la reproducción del comportamiento real de tres SFCR. Los resultados obtenidos muestran que los algoritmos meta-heurísticos son más eficientes que el algoritmo de Levenberg-Marquardt (LMA) especialmente en malas condiciones climáticas, aunque ambos modelos pueden ser utilizados para la supervisión y la detección automática de fallos. En esta tesis se presenta un nuevo enfoque para la supervisión automática y la detección remota de fallos en SFCR mediante la monitorización basada en la tecnología OPC. El procedimiento de detección de fallos utilizado para el diagnóstico de SFCR se basa en el análisis de los indicadores de corriente y tensión evaluados también a partir de datos monitorizados y valores esperados de corriente y tensión obtenidos a partir del modelo del generador fotovoltaico. Se han utilizado tres SFCR de diferentes tamaños, topologías y tecnologías fotovoltaicas para la validación experimental del método de detección de fallos propuesto. El análisis de los indicadores de corriente y tensión ha demostrado efectividad en la detección de los fallos más probables en generadores fotovoltaicos en tiempo real. Además, los resultados obtenidos muestran que la combinación de monitorización OPC junto con el procedimiento de detección de fallos propuesto es una herramienta robusta que puede ser muy útil en el campo de la supervisión remota y el diagnóstico de SFCR. Finalmente, en la presente tesis se aborda el estudio de los problemas de degradación de módulos fotovoltaicos de capa delgada correspondientes a cuatro tecnologías: a-Si:H, a-Si:H/µc-Si:H, CIS y CdTe, en condiciones de trabajo a la intemperie durante periodos prolongados de exposición. Se analiza el impacto de la degradación en la potencia de salida de los módulos fotovoltaicos para determinar su tasa de degradación anual y su período de estabilización. Los resultados obtenidos muestran que el módulo fotovoltaico CIS es el más estable comparado con las otras tecnologías, cuando trabajan en condiciones de clima continental mediterráneo. Los módulos fotovoltaicos a-Si:H y a-Si:H/µc-Si:H también presentan un buen comportamiento, mostrando tasas de degradación y períodos de estabilización similares a los esperados. El módulo de CdTe muestra las peores prestaciones, con una mayor tasa de degradación y un largo período de estabilización de 32 meses. Por último, se ha aplicado también la técnica de extracción de parámetros para analizar la evolución de los parámetros del modelo para generadores fotovoltaicos de módulos de a-Si: H y a-Si:H/µc-Si:H en condiciones reales de trabajo durante largos periodos de tiempo

Pathogénicité de l'adénovirus aviaire sérotype 11 sur les embryons de poulet exempts d'agents pathogènes spécifiques

Inclusion body hepatitis (IBH) associated with fowl aviadenovirus (FAdV) infection has a world-wide distribution, especially for broilers aged 3 to 5 weeks, causing significant economic losses to poultry industry. In present study, we evaluated the pathogenicity of Moroccan FAdV serotype 11 (MOR111115 strain) in specific pathogen free (SPF) white leghorn chicken embryos. FAdV (titre 10?/ml) was inoculated to SPF embryonated chicken eggs through the chorioallontoic membrane (CAM). The mortality, gross and microscopical lesions of the embryos were evaluated and the presence of the virus was checked by PCR. 100% cumulative embryonic mortality was observed at 7 days post-infection (dpi). The inoculated embryos were hemorragic and the liver was friable and swollen, with yellow to greenish discoloration. Microscopically, we highlighted a multifocal necrosis of hepatocytes groups with the presence of basophilic and eosinophilic intra-nuclear inclusion bodies within hepatocytes. The presence of the virus was confirmed by conventional polymerase chain reaction based on hexon gene from liver.that is a major target organ of FAdV infections. This is the first study of pathogenicity of fowl aviadenovirus in SPF chicken embryos in Morocco. Keywords: Fowl aviadenovirus-11, Inclusion body hepatitis, Pathogenicity, Chicken embryosL'hépatite à corps d'inclusion (IBH) associée à l'infection par l'aviadénovirus aviaire (FAdV) a une distribution mondiale, en particulier chez les poulets de chair âgés de 3 à 5 semaines, entraînant des pertes économiques importantes de l'industrie avicole. Dans la présente étude, nous avons évalué la pathogénicité du virus FAdV- sérotype 11 isolé au Maroc (souche MOR111115) chez les embryons de poulets exempts d’agent pathogène (SPF). Le FAdV (titre 10? / ml) a été inoculé à des œufs embryonnés SPF à travers la membrane chorioallontoique (CAM). La mortalité, les lésions macroscopiques et microscopiques des embryons ont été évaluées et la présence du virus a été confirmé par réaction de polymérisation en chaine (PCR). La mortalité embryonnaire cumulative de 100% a été observée 7 jours après l'infection (dpi). Les embryons inoculés étaient hémorragiques et le foie était hypertrophié et friable, avec une décoloration jaune à verdâtre. Au microscope, nous avons mis en évidence une nécrose multifocale des groupes d'hépatocytes avec la présence de corps d'inclusion intra-nucléaires basophiles et éosinophiles dans les hépatocytes. La présence du virus a été confirmée par PCR conventionnelle basée sur le gène hexon à partir des prélèvements du foie, qui constitue l’organe cible des infections à FAdV. Il s'agit de la première étude de la pathogénicité de l'aviadénovirus aviaire dans les embryons de poulet SPF au Maroc. Mots clés: Adénovirus aviaire, Hépatite à corps d’inclusion, Pathogénicité, Embryon de poule

De l’économie du développement à l’économie de la transition : une lecture de l’économie algérienne

La première partie de cet article fait le bilan de deux courants opposés de l’économie du développement : l’économie structuraliste (industrialiste) du développement des années 1960-85 et l’économie du développement éclectique tournée vers la transition à l’économie de marché. Une première hypothèse soutient que la théorie structuraliste du développement donne comme priorité l’accumulation, c’est-à-dire le processus de formation des actifs. Une seconde hypothèse pose que la théorie standard de la transition part d’une base d’actifs déjà plus ou moins constituée. La préoccupation est alors celle de la valorisation de ces actifs en économie de marché. La deuxième partie de cet article discute la dualité historique de l’économie en développement de l’Algérie sur la période 1963-2006. Une lecture critique souligne que l’ancrage structuraliste et la transition renvoient à leurs propres limites. Cette lecture conduit à proposer un dépassement théorique au croisement de l’économie structuraliste (industrialiste) et du vieil institutionnalisme américain.The article first part takes stock of two development economics conflicting trends: the development structuralist economics of the 1960-85 period, and the eclectic development economics whose subject is market economy transition. A first hypothesis upholds that accumulation (that is to say assets formation process) is given as priority in the development structuralist economics. The second hypothesis sets down that transition standard theory is based on assets basis more or less constituted already. The concern is then assets appreciation in market economy. The article second part discusses the historical duality of Algerian development economics of the 1963-2006 period. A critical analysis underlines structuralist basis and transition limits. This discussion leads to suggest theoretical overtaking between structuralist economics and American old institutionalism

Comparison of two PV array models for the simulation of PV systems using five different algorithms for the parameters identification

Simulation is of primal importance in the prediction of the produced power and automatic fault detection in PV grid-connected systems (PVGCS). The accuracy of simulation results depends on the models used for main components of the PV system, especially for the PV module. The present paper compares two PV array models, the five-parameter model (5PM) and the Sandia Array Performance Model (SAPM). Five different algorithms are used for estimating the unknown parameters of both PV models in order to see how they affect the accuracy of simulations in reproducing the outdoor behavior of three PVGCS. The arrays of the PVGCS are of three different PV module technologies: Crystalline silicon (c-Si), amorphous silicon (a-Si:H) and micromorph silicon (a-Si:H/µc-Si:H). The accuracy of PV module models based on the five algorithms is evaluated by means of the Route Mean Square Error (RMSE) and the Normalized Mean Absolute Error (NMAE), calculated for different weather conditions (clear sky, semi-cloudy and cloudy days). For both models considered in this study, the best accuracy is obtained from simulations using the estimated values of unknown parameters delivered by the ABC algorithm. Where, the maximum error values of RMSE and NMAE stay below 6.61% and 2.66% respectively.Peer ReviewedPostprint (author's final draft

Degradation analysis of thin film photovoltaic modules under outdoor long term exposure in Spanish continental climate conditions.

The present study analyses the degradation of thin film photovoltaic modules corresponding to four technologies: a-Si:H, a-Si:H/µc-Si:H, CIS and CdTe, under 5 years of outdoor long term exposure in Leganés, Spain. The period of outdoor exposure ranges from January 2011 to December 2015. The degradation rate and the stabilization period are analysed by using two different techniques. Moreover, the evolution of the fill factor and performance ratio is assessed. The CdTe module was found to have the highest degradation rate:-4.45 %/year, while the CIS module appears to be the most stable with a degradation rate of -1.04 %/year. The a-Si:H and a-Si:H/µc-Si:H modules present stabilization periods of 24 and 6 months respectively. The CdTe module degrades significantly for a period of 32 months, while the CIS module is the least degraded PV specimen over the whole experimental campaign.Peer ReviewedPostprint (author's final draft

Avian Hepatitis E virus: Preliminary investigations in layer hens and broiler breeders

L’hépatite virale E aviaire (AHVE), encore appelée maladie du gros foie et de la grosse rate, Big Liver and Spleen disease (BLS) est due à un Hepevirus de la famille des Orthohepevirus. Elle se manifeste par une mortalité brusque chez la poule pondeuse et la poule reproductrice, associée à une chute de ponte sans dégradation de la qualité des œufs. Elle est d’apparition récente et a été rapportée dans quelques pays seulement dont les USA, le Canada, l’Espagne, la Hongrie, la Chine et la Pologne. Depuis quelques années, des mortalités brusques pouvant atteindre 0.3% par semaine et des chutes de ponte pouvant aller jusqu’à 12-15 % ont constitué régulièrement des motifs de consultations. Le diagnostic lésionnel macroscopique n’est pas évident en raison de la similitude des lésions observées sur le foie avec celles rencontrées dans le cas des stéatoses hépatiques, pathologie avec laquelle le diagnostic différentiel s’impose. Les lésions trouvées généralement consistent en une hépatomégalie avec présence ou non d’une stéatose, cependant les hémorragies sont toujours constantes avec une splénomégalie variable. Le présent travail se rapporte à des investigations préliminaires réalisées sur plusieurs cas de poules pondeuses et de reproductrices présentant les symptômes et lésions précitées. Outre les aspects épidémiologiques et lésionnels macroscopiques observés, les investigations ont porté sur l’analyse des résultats des examens anatomo-pathologiques, des sérologies Elisa réalisées sur des sérums provenant des élevages concernés, de même que la réalisation sur les foies et rates d’animaux atteints de tests de PCR en temps réel spécifiques à cette pathologie. Parallèlement, une étude séro-épidémiologique a porté sur un échantillon de 9255 sérums prélevés durant les années 2017 à 2020. Les résultats préliminaires sont mitigés mais pointent davantage sur la nécessité d’élargir le champ d’investigation en développant les outils de diagnostic sérologiques et moléculaires plus spécifiques au contexte épidémiologique marocain. Cette étude rapporte les premières descriptions de la pathologie au Maroc.   Mots clés: Hépatite virale E, Stéatose hépatique, anatomopathologie, RT-PCR, ELISAAvian Viral hepatitis E (VHE), also called Big Liver and Spleen disease (BLS) is caused by a Hepevirus of the Orthohepevirus family.  It is characterized by sudden death in laying and breeding hens, associated with an egg drop and no degradation of egg quality.  It is of recent occurrence and has been reported in only a few countries including the US, Canada, Hungary, Spain, China and Poland.  During latest years, sudden mortalities of up to 0.3% per week and drops in production of up to 12-15% have been regular reasons for consultations.  The macroscopic pathologic diagnosis was not obvious because of similarities between lesions observed on livers of VHE affected birds and those encountered in the case of hepatic steatosis, pathology with which the differential diagnosis is essential.  The lesions found generally consisted of hepatomegaly with or without the presence of steatosis. However, hepatic bleeding is constant always present with varying splenomegaly. The present work describes preliminary results of investigations carried out on several farm-cases of laying hens and breeders presenting the aforementioned clinical signs and lesions.  In addition to the epidemiological aspects and macroscopic changes observed, the investigations performed included histopathological examinations, Elisa serology carried out on sera from the affected farms, as well as specific real-time PCR testing on liver and spleen samples.  In parallel, a sero-epidemiological analysis focused on a batch of 9,255 sera harvested from layers and breeders during the years 2018 to 2020.  The preliminary results are mixed up but point out more the need to broaden the field of investigation by developing serological and molecular diagnostic tools more specific to the Moroccan epidemiological context.  This study reports the first descriptions of the disease in Morocco.  Key words: Hepatitis E virus, Big liver and spleen, Fatty liver, anatomopathology, RT-PCR, ELIS

Avortements et séroprévalence de la chlamydiose et de la brucellose chez les caprins dans les provinces de Chefchaoune et Tétouan (Maroc)

In order to determine the importance of abortions and the seroprevalence of two abortive infections namely brucellosis and chlamydiosis in goats in the Northern area of Morocco, a survey was carried out in 11 goat herds and 5 slaughter houses from the provinces Chefchaouene and Tetouan. A total of 374 serums was collected from slaughtered goats. In herds, 26 and 55 samples were collected from goats with and without history of abortion, respectively. Screening for brucellosis was conducted using the Card-test and for chlamydiosis using the micro- method of the complement fixation test. Mean abortion rate in surveyed herds was 25%. All tested sera were negative for brucellosis. However, chlamydisois was found to be prevalent with a mean prevalence rate of 14.8%. A prevalence of 19.2% was found in aborting goats against 12.7% in non aborting ones. The seroprevalence in adult-goats sampled and tested in slaughterhouses was found to be of 16.9%. Keywords: Goats - Abortion - Brucellosis - Chlamydiosis - Chefchaouene - Tetouan - MoroccoDans le but de déterminer l’importance des avortements et la séroprévalence de deux infections abortives à savoir la brucellose et la chlamydiose chez les caprins dans les provinces du Nord, une enquête sérologique a été réalisée au niveau de 5 abattoirs ruraux et de 11 élevages de la province de Chefchaouène et de Tétouan. Un total de 374 échantillons de sérums a été prélevé à partir de caprins abattus au niveau des 5 abattoirs. Au niveau des élevages, des enquêtes sur les avortements ont été réalisées et des prises de sang ont été effectuées sur 26 chèvres ayant avorté et 55 chèvres ayant mis bas normalement. Le dépistage sérologique de la brucellose a été réalisé par le test à l’antigène tamponné (Card-Test) et celui de la chlamydiose par la technique de fixation du complément selon une micro-méthode de type Kolmer. La fréquence des avortements dans les élevages enquêtés était de 25%. Aucun sérum ne s’est révélé positif à la brucellose. La chlamydiose a été détectée dans 6 parmi les 11 élevages visités avec une séroprévalence globale de 14,8%. Le pourcentage de séropositivité enregistré chez les chèvres avortantes testées est de 19,2% contre 12,7% chez les chèvres à mise bas normale. Pour les échantillons de sérums prélevés à partir de femelles adultes abattues dans les 5 abattoirs précités, une séroprévalence chlamydienne totale de 16,9% a été enregistrée. Mots clés: Caprins - Avortements - Brucellose - Chlamydiose - Chefchaouène - Tétouan - Maro

Remote supervision and fault detection on OPC monitored PV systems

This paper presents a new approach for automatic supervision and remote fault detection of grid connected photovoltaic (PV) systems by means of OPC technology-based monitoring. The use of standard OPC for monitoring enables data acquisition from a set of devices that use different communication protocols as inverters or other electronic devices present in PV systems enabling universal connectivity and interoperability. Using the OPC standard allows promoting interoperation of software objects in distributed-heterogeneous environments and also allows incorporating in the system remote supervision and diagnosis for the evaluation of grid connected PV facilities. The supervision system analyses the monitored data and evaluates the expected behaviour of main parameters of the PV array: Output voltage, current and power. The monitored data and evaluated parameters are used by the fault detection procedure in order to identify possible faults present in the PV system. The methodology presented has been experimentally validated in the supervision of a grid connected PV system located in Spain. Results obtained show that the combination of OPC monitoring along with the supervision and fault detection procedure is a robust tool that can be very useful in the field of remote supervision and diagnosis of grid connected PV systems. The RMSE between real monitored data and results obtained from the modelling of the PV array were below 3.6% for all parameters even in cloudy days.Peer ReviewedPostprint (published version

Immunodéficience combinée chez le poulain Arabe

L'immunodéfience combinée a été diagnostiquée chez trois poulains pur-sang Arabe nés au Maroc. Cliniquement, ces animaux ont présenté une pneumonie chronique rebelle à une antibiothérapie intense. Sur le plan histopathologique, une sévère hypoplasie lymphoïde a été notée au niveau des organes lymphoïdes en association avec des pneumopathies à adénovirus