Performance of the Bond Graph Approach for the Detection and Localization of Faults of a Refrigerator Compartment Containing an Ice Quantity

Abderrahmene Sellami,Emna Aridhi,Dhia Mzoughi,Abdelkader Mami 대한설비공학회 2018 International Journal Of Air-Conditioning and Refr Vol.26 No.3

In this paper, a robust fault diagnosis for a refrigerator compartment containing a quantity of ice using the bond graph (BG) approach is performed by linear fractional transformations (LFTs). The BG model describes heat transfers supported by the amount of ice placed in the refrigerator compartment, as well as a water container. The LFT modeling of BG elements offers advantages from the point of view of structural analysis and data processing implementation. We have introduced four faults, which consist of ice temperature rise, water leakage, insulation failure at the hot walls of the refrigerator and an increase of the internal temperature due to poor door sealing. The faults are in the form of additional heat fluxes. The simulation results show the effectiveness of the proposed method for detecting and localizing faults. In addition, the lack of door sealing has the most influence on the temperatures in the internal cooling space, water, and ice compared to the other faults.

Initiation and propagation of a crack in the orthopedic cement of a THR using XFEM

Gasmi, Bachir,Abderrahmene, Sahli,Smail, Benbarek,Benaoumeur, Aour Techno-Press 2019 Advances in computational design Vol.4 No.3

The sealing cement of total hip arthroplasty is the most widely used binder in orthopedic surgery for anchoring implants to their recipient bones. Nevertheless, this latter remains a fragile material with weak mechanical properties. Inside this material cracks initiate from cavities. These cracks propagate under the effect of fatigue and lead to the failure of this binder and consequently the loosening of the prosthesis. In this context, this work consists to predict the position of cracks initiation and their propagations path using the Extended Finite Element Method (XFEM). The results show that cracks can only be initiated from a sharp edges of an ellipsoidal cavity which the ratio of the minor axis over the major axis is equal to 0.1. A maximum crack length of 19 ?m found for a cavity situated in the proximal zone position under a static loading. All cracks propagate in same(almost) way regardless of the cavity(site of initiation) position and its inclination in the proximal zone.

Influence of hydraulic retention time on biogas production during leachate treatment

Souaad Baati,Fatima Benyoucef,Abdelhadi Makan,Abdelaziz El Bouadili,Abderrahmene El Ghmari 대한환경공학회 2018 Environmental Engineering Research Vol.23 No.3

The main objective of this study is to investigate the influence of hydraulic retention time (HRT) on biogas production during leachate treatment using an anaerobic reactor type Upflow Anaerobic Sludge Blanket. For this purpose, four HRTs ranging from 12 to 48 h were experienced. The obtained results showed that higher amount of biogas could be produced during longer HRTs. However, HRTs longer than 48 h could not affect clearly the biogas generation and considered as unnecessary given the small additional amount of biogas produced during the degradation process. A volume of 0.434 L/Lleachate/d was achieved during the treatment with a HRT of 48 h. The higher biogas production, the smaller chemical oxygen demand (COD) values achieved. Besides, COD removal and biogas production positively correlate, showing that the active biomass has degraded effectively the organic load to produce biogas. Moreover, all the analyzed physicochemical parameters have experienced a decrease after 48 h except for the pH, which increased to approximately neutral value. More precisely, a decrease of 93.8%, 89.7%, 95%, 70%, 77%, and 84.4% was recorded for COD, electrical conductivity, total suspended solid, turbidity, NH₄⁺-N, and NO₃⁻-N, respectively.

KMMR: An Efficient and scalable Key Management Protocol to Secure Multi-Hop Communications in large scale Wireless Sensor Networks

( Abderrahmen Guermazi ),( Abdelfettah Belghith ),( Mohamed Abid ),( Sofien Gannouni ) 한국인터넷정보학회 2017 KSII Transactions on Internet and Information Syst Vol.11 No.2

Efficient key distribution and management mechanisms as well as lightweight ciphers are the main pillar for establishing secure wireless sensor networks (WSN). Several symmetric based key distribution protocols are already proposed, but most of them are not scalable, yet vulnerable to a small number of compromised nodes. In this paper, we propose an efficient and scalable key management and distribution framework, named KMMR, for large scale WSNs. The KMMR contributions are three fold. First, it performs lightweight local processes orchestrated into upward and downward tiers. Second, it limits the impact of compromised nodes to only local links. Third, KMMR performs efficient secure node addition and revocation. The security analysis shows that KMMR withstands several known attacks. We implemented KMMR using the NesC language and experimented on Telosb motes. Performance evaluation using the TOSSIM simulator shows that KMMR is scalable, provides an excellent key connectivity and allows a good resilience, yet it ensures both forward and backward secrecy. For a WSN comprising 961 sensor nodes monitoring a 60 hectares agriculture field, KMMR requires around 2.5 seconds to distribute all necessary keys, and attains a key connectivity above 96% and a resilience approaching 100%. Quantitative comparisons to earlier work show that KMMR is more efficient in terms of computational complexity, required storage space and communication overhead.

Genetic analysis of milk production traits of Tunisian Holsteins using random regression test-day model with Legendre polynomials

Zaabza, Hafedh Ben,Gara, Abderrahmen Ben,Rekik, Boulbaba Asian Australasian Association of Animal Productio 2018 Animal Bioscience Vol.31 No.5

Objective: The objective of this study was to estimate genetic parameters of milk, fat, and protein yields within and across lactations in Tunisian Holsteins using a random regression test-day (TD) model. Methods: A random regression multiple trait multiple lactation TD model was used to estimate genetic parameters in the Tunisian dairy cattle population. Data were TD yields of milk, fat, and protein from the first three lactations. Random regressions were modeled with third-order Legendre polynomials for the additive genetic, and permanent environment effects. Heritabilities, and genetic correlations were estimated by Bayesian techniques using the Gibbs sampler. Results: All variance components tended to be high in the beginning and the end of lactations. Additive genetic variances for milk, fat, and protein yields were the lowest and were the least variable compared to permanent variances. Heritability values tended to increase with parity. Estimates of heritabilities for 305-d yield-traits were low to moderate, 0.14 to 0.2, 0.12 to 0.17, and 0.13 to 0.18 for milk, fat, and protein yields, respectively. Within-parity, genetic correlations among traits were up to 0.74. Genetic correlations among lactations for the yield traits were relatively high and ranged from $0.78{\pm}0.01$ to $0.82{\pm}0.03$, between the first and second parities, from $0.73{\pm}0.03$ to $0.8{\pm}0.04$ between the first and third parities, and from $0.82{\pm}0.02$ to $0.84{\pm}0.04$ between the second and third parities. Conclusion: These results are comparable to previously reported estimates on the same population, indicating that the adoption of a random regression TD model as the official genetic evaluation for production traits in Tunisia, as developed by most Interbull countries, is possible in the Tunisian Holsteins.

Comparison of the Effects of Four Cooking Methods on Fatty Acid Profiles and Nutritional Composition of Red Mullet (Mullus barbatus) Muscle

Aida Koubaa,Nourhène Boudhrioua Mihoubi,Abdelwaheb Abdelmouleh,Abderrahmen Bouain 한국식품과학회 2012 Food Science and Biotechnology Vol.21 No.5

This study was performed to examine the effects of different cooking methods (frying, steaming, oven cooking, and microwave cooking) on proximate chemical composition, mineral contents, and fatty acids profiles of red mullet (Mullus barbatus) fillets. The frying process caused a significant increase in fat content (from 13.37±0.04 to 34.44±0.20 g/100 g d.w.) and reduced the proportion of the palmitic acid of 50.73% and saturated fatty acids of 56.9%. While, the proportion of polyunsaturated fatty acids (PUFA) increased from 4.04% of total fatty acids for raw fillet to 49.17% of total fatty acids for fried fillets. The steamed, oven-cooked, and microwave-cooked fillets showed the best proportion of fat content, PUFA, and ω-6/ω-3 ratio as compared with fried red mullet fillets. Na, Mg,and Zn contents of cooked fish fillets significantly decreased.