Papers by Abdelkader Hammami
Journal of Horticulture and Forestry, Aug 31, 2010
Leaf analysis is a useful tool to evaluate the nutrient status of citrus trees, but diagnosis sta... more Leaf analysis is a useful tool to evaluate the nutrient status of citrus trees, but diagnosis standards for 'Clementine mandarin' are not available. Nutrition recommendations of the current fertilization practices are mainly based on the same recommended nutrient rates for orange trees. A three-year (2005-2007) field experiment was conducted in North Eastern Tunisia (El Gobba). This experiment was carried out using 25 years old 'Clementine mandarin' trees (Citrus reticulata Osbeck) on 'Sour orange' (Citrus aurantium Osbeck) rootstock; grown on a sandy soil; to establish leaf nutrient (N and K) concentration standards for optimum biomass tree growth, fruit production and quality. Nitrogen and potassium rates ranging from 160 to 232 and 200 to 290 kg/ha/yr, respectively, were applied in a drip irrigation system (12 fertigations events/yr). Irrigation was scheduled based on tensiometer readings at the root zone. Fruit yield was positively associated with N (r 2 = 0.91) and K (r 2 = 0.84) rates; as well as with leaf N concentration (r 2 = 0.92) and tree fruit load (r 2 = 0.91). Leaf N concentration was significantly correlated with N rates (r 2 = 0.72) and biomass tree growth (r 2 = 0.52). These findings indicate that 192 and 200 kg/ha/yr of N and K 2 O (N:K = 0.9), respectively, are required to support optimal fruit yield of 43 T/ha/yr with tree fruit load of 2.4 kg/m 3 (fruit yield/tree canopy size ratio) and optimum fruit quality. At 90% of maximum relative fruit yield, leaf N and K concentrations were 27 to 29 and 10 to 12 g/kg , respectively. Leaf nutrient concentration ranging from 27 to 29 g/kg for N; and from 10 to 12 g/kg for K corresponding to a fertilizer management program of 192 kg/ha/yr and 200 kg/ha/yr, could be recommended as optimum levels of N and K for 'Clementine mandarin' grown under Mediterranean conditions.
A mes parents A tous ceux qui me sont chersRESUME COURT tel-00797918, version 1- 7 Mar 2013 Cette... more A mes parents A tous ceux qui me sont chersRESUME COURT tel-00797918, version 1- 7 Mar 2013 Cette thèse est une contribution au traitement du problème de conception et de pilotage d’une chaîne logistique dans un réseau d’entreprises. Elle examine plus spécifiquement le cas d’un réseau coopératif où tous les partenaires jouissent des mêmes privilèges (il n’y a pas de partenaire leader). Compte tenu des différents problèmes inhérents à ce type d’organisations, une démarche d’aide à la décision basée sur les concepts d’optimisation multicritère a été proposée. Cette démarche consiste à répartir les activités entre membres du réseau en deux étapes. Elle permet de satisfaire simultanément les objectifs de performance à court terme et d’évolution de compétences à long terme au sein du réseau. Par ailleurs, elle intègre l’aspect stochastique qui peut affecter la performance globale de ce type d’organisations et ce à travers un modèle basé sur les concepts de fiabilité. La thèse a débouché ...
Leaf nitrogen and potassium concentrations for optimum fruit production, quality and biomass tree... more Leaf nitrogen and potassium concentrations for optimum fruit production, quality and biomass tree growth in Clementine mandarin under
Leaf analysis is a useful tool to evaluate the nutrient status of citrus trees, but diagnosis sta... more Leaf analysis is a useful tool to evaluate the nutrient status of citrus trees, but diagnosis standards for ‘Clementine mandarin’ are not available. Thus, a three-year (2005-2007) field experiment was conducted in North East Tunisia with 25 years old ‘Clementine mandarin’ trees (Citrus reticulata Osbeck) on ‘Sour orange’ (Citrus aurantium Osbeck) rootstock; grown on a sandy soil (loamy mixed thermic mollic xerofluvent); to establish leaf nutrient (N and K) concentration standards for optimum fruit production and Quality. Nitrogen and potassium rates from 160 to 232 kg ha-1yr-1 and 200 to 290 kg ha-1yr-1, respectively, were applied through a drip irrigation system. Irrigation was scheduled based on tensiometer readings at the root zone. Fruit yield was significantly correlated with N (r2=0.91) and K (r2=0.84) rates; it was also correlated with leaf N concentrations (r2=0.92). These findings indicate that 192 and 200 kg ha-1yr-1 of N and K2O, respectively, are needed to support optima...
The Proceedings of the International Plant Nutrition Colloquium Xvi, Jun 23, 2009
Collaborative Business Ecosystems and Virtual Enterprises, 2002
Networks of SMEs can be seen as particular instantiations of the virtual enterprise concept. Due ... more Networks of SMEs can be seen as particular instantiations of the virtual enterprise concept. Due to the reactivity and flexibility abilities required by this emerging organisation, modelling frameworks need to be adapted. For this purpose, a diagnostic-based framework, able to capture the organisational evolutions is proposed and connected to traditional modelling approaches so that configuration models and strategic scenarii can be integrated.
Collaborative Business Ecosystems and Virtual Enterprises, 2002
This paper describes a case study about an order allocation method for networks of firms. The met... more This paper describes a case study about an order allocation method for networks of firms. The method we present aims to calculate satisfying routes for each order, according to antagonist criteria such as resource occupation and knowledge acquisition. The order allocation procedure is first based on a product description (focusing on required activities and competencies), and second on the identification of the available competencies within networks of SMEs. Thanks to several work meetings, the network partners can define the strategy of the network and the policy of competencies development. These decisions enable us to represent the competencies map as below:
RESUME: L'évolution du contexte économique a remis en question les stratégies manufacturières des... more RESUME: L'évolution du contexte économique a remis en question les stratégies manufacturières des entreprises qui se sont trouvées obligées de rationaliser leurs efforts, pour consolider leurs positions sur le marché. Pour ce faire, certaines se sont regroupées en des structures en réseau rendues possibles grâce aux technologies de l'information et de la communication. La dynamique de ces architectures industrielles a intéressé des chercheurs de différentes disciplines. On se propose dans cette communication, de faire le point sur des éléments relatifs à l'étude des structures en réseau, à savoir la modélisation et les chaînes logistiques, pour s'intéresser ensuite de plus près à un modèle coopératif d'entreprise réseau, à sa configuration, sa dynamique et ses mécanismes de prise de décision.
All Days, 1997
Four commercial solvents and o-xylene have been tested for their effectiveness in remediating par... more Four commercial solvents and o-xylene have been tested for their effectiveness in remediating paraffin (wax) depositions from three different dead oils. The dead oils were sampled from the North Sea, Alberta and Gulf of Mexico, respectively. Representative field solvent/oil concentrations of 2000 and 4000 ppm (vol) were prepared for each oil and solvent considered in this work. Two state-of-the-art techniques, namely a cross polar microscopy (CPM) and a rheometrics mechanical spectrometer (RMS 800), were used to study paraffin crystal habits and/or morphologies at 32°F, wax dissolution temperatures (WDT), and pour point temperatures of the three dead oils with and without solvents. It is found that in almost all cases, the 2000 ppm (vol) solvent concentration yielded similar or better remediation results than mixtures with 4000 ppm (vol) solvents. More importantly, it is shown that the remediation of wax deposition depends not only on the solvent concentration but also the type of o...
Proceedings of the 15th IFAC World Congress, 2002, 2002
This paper exposes an order allocation model for networks of firms. We assume that networks of fi... more This paper exposes an order allocation model for networks of firms. We assume that networks of firms need e-manufacturing tools to coordinate fairly their collaborative activities, and that these tools must both prevent opportunism and enable learning processes within networks. The tool we present aims to calculate satisfying routes for each order, according to antagonist criteria such as resource occupation and knowledge acquisition.
Médecine et Maladies Infectieuses, 2008
International Journal of Production Economics, 2003
In a context of profound transformation of the relations between firms, an organizational paradig... more In a context of profound transformation of the relations between firms, an organizational paradigm is developing rapidly: the network. Networks of firms are specific co-ordination modes between market and hierarchy, and need collaborative tools to regulate their activities fairly and to limit opportunism. This paper exposes a method to calculate satisfying routes for customers’ orders within manufacturing networks of SMEs. This method aims at designing the routing of activities, so as to meet the customers’ needs in terms of cost, quality and delivery time (short-term performance constraints), and to promote learning processes and skills exchanges within the network (long-term performance criteria). The method is illustrated with a case study.
International Journal of Computer Integrated Manufacturing, 2005
ABSTRACT
Fuel, 1996
The liquid-solid phase behaviour and thermal characteristics of n-C&H52 + n-CZ8H5s and n-C44H90+ ... more The liquid-solid phase behaviour and thermal characteristics of n-C&H52 + n-CZ8H5s and n-C44H90+ n-C~oH,~z binary systems have been studied using differential scanning calorimetry (d.s.c.). Both the melting and crystallization thermograms for n-C2sH52 f n-C2sH5s mixtures exhibited two major peaks (CZ and p) corresponding to the liquid-solid and solid-solid transitions. Hence, isomorphous solid solutions were formed in these mixtures. The ~-CUH~~ + n-C50H102 mixtures displayed eutectic or isomorphous behaviour depending on the thermal treatment of prepared samples. A recently proposed model for the non-isothermal crystallization kinetics of pure n-paraffins has been extended to binary mixtures by deriving appropriate mixing rules for the three parameters in the model. Accurate predictions of the onset-of-crystallization temperature for the n-C25H52 + n-C2sHSs and the n-CUH9,, + n-C 5O H 102 binary systems were obtained at different cooling rates. Predictions of the relative crystallinity in the isomorphous mixtures have been presented and compared with the data.
Publikationsansicht. 31009435. Modélisation technico-économique d'une chaîne logistique d... more Publikationsansicht. 31009435. Modélisation technico-économique d'une chaîne logistique dans une entreprise réseau / (2003). Hammami, Abdelkader. Abstract. Thèse de doctorat présentée en cotutelle à la Faculté des sciences ...
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Papers by Abdelkader Hammami