Experimentally Validated Model of a Domestic Refrigerator with an Immersed Condenser Coil for Water Heating

Missaoui Sami,Driss Zied,Ben Slama Romdhane,Chaouachi Bechir 대한설비공학회 2021 International Journal Of Air-Conditioning and Refr Vol.29 No.3

This study presents a coupled model to simulate the heat transfer process between the helical condenser coil and the water inside the tank. This coupled model was developed using ANSYS Fluent Computational Fluid Dynamics (CFD). The heat flux of the condenser coils is obtained from our experimental investigation and delivered as initial boundary conditions to the tank model. The results obtained are considered essential and are, in turn, capable of assessing the performance of the modified domestic refrigerator for the production of hot water. According to this model, the results confirmed that the coefficient of heat transfer and the performance of the system decreased with an increase in the heating time. The natural heat transfer coefficient Uc falls from 727.26[Formula: see text]W [Formula: see text] m[Formula: see text] [Formula: see text] K[Formula: see text] to 68.64[Formula: see text]W [Formula: see text] m[Formula: see text] [Formula: see text] K[Formula: see text] during the total heating cycle, and the water temperature rises from 20 ∘ C to 50.73∘ C. In addition, the impact of water temperature on the evaporating region was used in this analysis. Therefore, the temperature of the evaporator is unaffected by the development of hot water. As a result, these outcomes will be used for the development of the domestic refrigerator with immersed condenser coil.

Effects of pipe turns on vertical helically coiled tube heat exchangers for water heating in a household refrigerator

Missaoui Sami,Driss Zied,Slama Romdhane Ben,Chaouachi Bechir 대한설비공학회 2022 International Journal of Air-Conditioning and Refr Vol.30 No.1

A new coupled numerical model of the overall vapor-compression cycle and water heater was developed in order to analyze the influence of condenser coil designs on the heat transfer process of a helical coil heat exchanger immersed in a storage tank. The model was developed using the CFD code ANSYS Fluent. In the numerical simulation, the helical condenser coil was treated as an internal heat source and the initial heat flux was obtained from experimental results and delivered to each coil element in the CFD model as boundary condition.The coupled model was validated with experimental results and showed that the numerical results of the proposed model are in good agreement with the experimental data with the deviation of ± 1.6%. Then, the impact of the main representative geometrical parameter on the overall heat transfer coefficient and water temperature distribution was investigated. The results indicated that the temperature distribution and overall heat transfer coefficient increase with the increase of the pipe turns of a helically coiled tube heat exchanger.

HER2 Expression in Ovarian Mucinous Carcinomas in Tunisia

Missaoui, Nabiha,Abdelkarim, Soumaya Ben,Ayachi, Malak,Hmissa, Sihem Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.19

Background: Ovarian mucinous carcinoma has a poor prognosis in advanced stages and a poor response to conventional chemotherapy. An efficient treatment is not yet available. We heere investigated HER2 expression and the potential for trastuzumab therapy in ovarian mucinous tumors. Materials and Methods: Immunohistochemistry was performed in formalin-fixed, paraffin-embedded tissue from 27 ovarian mucinous tumors including 14 carcinomas and 13 borderline tumors diagnosed in the Pathology Department, Farhet Hached Hospital, Sousse, between 1993 and 2013. The HercepTest (DAKO) was used for immunohistochemistry. Results: HER2 expression was observed in only one borderline tumor (7.7%) and in 14.3% of mucinous carcinomas of the ovary. Conclusions: Our results suggest that trastuzumab therapy would be an option for patients with mucinous carcinoma when the tumor has HER2 overexpression.

Prognostic Factors of Prostate Cancer in Tunisian Men: Immunohistochemical Study

Missaoui, Nabiha,Abdelkarim, Soumaya Ben,Mokni, Moncef,Hmissa, Sihem Asian Pacific Journal of Cancer Prevention 2016 Asian Pacific journal of cancer prevention Vol.17 No.5

Background: Prostate cancer is the second most common male cancer and remains a leading cause of cancer death worldwide. Heterogeneity regarding recurrence, tumor progression and therapeutic response reflects the inadequacy of traditional prognostic factors and underlies interest in new genetic and molecular markers. In this work, we studied the prognostic value of the expression of 9 proteins, Ki-67, p53, Bcl-2, PSA, HER2, E-cadherin, $p21^{WAF1/Cip1}$, $p27^{Kip1}$ and $p16^{ink4a}$ in prostate cancer. Materials and Methods: We conducted a retrospective study of 50 prostate cancers diagnosed in Pathology Department of Farhet Hached Hospital, Sousse, Tunisia, during a period of 12 months. Clinico-pathological data and survival were investigated. Protein expression was analyzed by immunohistochemistry on archived material. Results: Expression or over-expression of Ki-67, p53, Bcl-2, PSA, HER2, E-Cadherin, $p21^{WAF1/Cip1}$, $p27^{Kip1}$ and $p16^{ink4a}$ was observed in 68%, 24%, 32%, 78%, 12%, 90%, 20%, 44% and 56% of cases, respectively. Overall five-year survival was 68%. A statistically significant correlation was observed between death occurrence and advanced age (p=0.018), degree of tumor differentiation (p=0.0001), perineural invasion (p=0.016) and metastasis occurrence (p=0.05). Death occurrence was significantly correlated with the expression of p53 (p=0.007), Bcl-2 (p=0.02), Ki-67 (p=0.05) and $p27^{Kip1}$ (p=0.04). Conclusions: The p53, Bcl-2, Ki-67 and $p27^{Kip1}$ proteins may be useful additional prognostic markers for prostate cancer. The use of these proteins in clinical practice can improve prognosis prediction, disease screening and treatment response of prostatic cancer.

p16^INK4A Expression in Squamous Cell Carcinomas of the Vagina and the Vulva in Tunisian Women

Missaoui, Nabiha,Abdelkarim, Soumaya Ben,Mokni, Moncef,Hmissa, Sihem Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.24

Background: The role of $p16^{INK4A}$ expression in uterine cervix cancer is well established. In the remaining female lower genital tract cancers, the importance of $p16^{INK4A}$ up-regulation is less clear. In our study, we analyzed the role of $p16^{INK4A}$ expression and HPV infection in carcinomas of the vulva and the vagina in Tunisian women. Materials and Methods: We conducted a retrospective study of 30 carcinomas including 15 vulvar squamous cell carcinomas (SCCs) and 15 vaginal SCCs. Immunohistochemistry was used to determine $p16^{INK4A}$ expression. HPV detection and typing was by in situ hybridization. Results: $p16^{INK4A}$ expression was detected in 86.7% of vaginal SCCs with a strong and diffuse immunostaining in 60% of cases, and also in 73.3% of vulvar SCCs with focal immunoreactivity in 53.3% The association between $p16^{INK4A}$ expression and HPV infection was significant in vaginal SCCs (p=0.001) but not vulvar SCCs (p>0.05). Conclusions: $p16^{INK4A}$ expression could be used as a useful marker for HPV positivity in vaginal SCCs similar to that described in uterine cervix cancers. However, our data support the presence of 2 different mechanisms for $p16^{INK4A}$ expression in HPV-related and HPV-unrelated vulvar carcinomas.

A Data Mining Approach for Selecting Bitmap Join Indices

Bellatreche, Ladjel,Missaoui, Rokia,Necir, Hamid,Drias, Habiba Korean Institute of Information Scientists and Eng 2007 Journal of Computing Science and Engineering Vol.1 No.2

Index selection is one of the most important decisions to take in the physical design of relational data warehouses. Indices reduce significantly the cost of processing complex OLAP queries, but require storage cost and induce maintenance overhead. Two main types of indices are available: mono-attribute indices (e.g., B-tree, bitmap, hash, etc.) and multi-attribute indices (join indices, bitmap join indices). To optimize star join queries characterized by joins between a large fact table and multiple dimension tables and selections on dimension tables, bitmap join indices are well adapted. They require less storage cost due to their binary representation. However, selecting these indices is a difficult task due to the exponential number of candidate attributes to be indexed. Most of approaches for index selection follow two main steps: (1) pruning the search space (i.e., reducing the number of candidate attributes) and (2) selecting indices using the pruned search space. In this paper, we first propose a data mining driven approach to prune the search space of bitmap join index selection problem. As opposed to an existing our technique that only uses frequency of attributes in queries as a pruning metric, our technique uses not only frequencies, but also other parameters such as the size of dimension tables involved in the indexing process, size of each dimension tuple, and page size on disk. We then define a greedy algorithm to select bitmap join indices that minimize processing cost and verify storage constraint. Finally, in order to evaluate the efficiency of our approach, we compare it with some existing techniques.

The Market Orientation from Dual Perspectives: Customers and Managers Perceptions in Tunisian Banks

Najjar, Faouzi,Missaoui, Yosra International Journal of Computer ScienceNetwork S 2021 International journal of computer science and netw Vol.21 No.11

Several studies have been conducted on market orientation over the last three decades. However, the majority of previous research focused exclusively on an internal vision that conceives the market orientation from an organizational perspective, considering the market orientation as a strictly perceived culture or behavior by company's staff (managers and employees) .This study aims to emphasize the importance of analyzing the market orientation from a dual perspective by investigating simultaneously the perceptions of customers and those of managers. It examines the perceptual gap or perceptual congruence of market orientation between customers and managers. A survey is conducted with Tunisian bank managers and B to B customers to measure their market orientation perception. The results should reveal level of manager's market orientation in Tunisian banks compared to customers' perceptions. The perception gaps of market orientation between managers and customers named congruence is highlighted and categorized. This study provides some contributions to fill the gap emerging from the one-sidedness of market orientation evaluation and gives a dyadic vision of market orientation that helps managers in their continuous learning about markets and sensing customers' needs and expectations. Market orientation level between the two groups is evaluated to give some managerial recommendations.

A Data Mining Approach for Selecting Bitmap Join Indices

Ladjel Bellatreche,Rokia Missaoui,Hamid Necir,Habiba Drias 한국정보과학회 2007 Journal of Computing Science and Engineering Vol.1 No.2

Index selection is one of the most important decisions to take in the physical design of relational data warehouses. Indices reduce significantly the cost of processing complex OLAP queries, but require storage cost and induce maintenance overhead. Two main types of indices are available: mono-attribute indices (e.g., B-tree, bitmap, hash, etc.) and multi-attribute indices (join indices, bitmap join indices). To optimize star join queries characterized by joins between a large fact table and multiple dimension tables and selections on dimension tables, bitmap join indices are well adapted. They require less storage cost due to their binary representation. However, selecting these indices is a difficult task due to the exponential number of candidate attributes to be indexed. Most of approaches for index selection follow two main steps: (1) pruning the search space (i.e., reducing the number of candidate attributes) and (2) selecting indices using the pruned search space. In this paper, we first propose a data mining driven approach to prune the search space of bitmap join index selection problem. As opposed to an existing our technique that only uses frequency of attributes in queries as a pruning metric, our technique uses not only frequencies, but also other parameters such as the size of dimension tables involved in the indexing process, size of each dimension tuple, and page size on disk. We then define a greedy algorithm to select bitmap join indices that minimize processing cost and verify storage constraint. Finally, in order to evaluate the efficiency of our approach, we compare it with some existing techniques.