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Anisotropic Structure of Glass Wool Determined by Air Permeability and Thermal Conductivity Measurements

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Journal of Surface Engineered Materials and Advanced Technology 2016年第2期6卷 72-79页

作者： Laurent Marmoret Hussein Humaish Anne Perwuelz hassen Béji Université de Picardie Jules Verne-Laboratoire des Technologies Innovantes-Equipe Phénomènes de Foundation of Technical Institutes Technical Institute Department of Surveying Al-Kut Iraq University Lille-Nord de France Lille France ENSAIT GEMTEX Roubaix France

We want to conclude on the interest of the “crimping” process used to produce the glass wool and to make a comparison for anisotropic factor obtained from structural property (air permeability) as well as thermal property (thermal conductivity and diffusivity). The main structural (densities, porosity, specific surface, air permeability) and the thermal (conductivity, diffusivity, heat capacity) characteristics of this glass wool are presented. Thermal results are determined by using several methods (Hot disc (HD), Heat Flow Meter (HFM) and Guarded Hot Plate).

关键词： Fibrous Insulation Material Glass Wool Air Permeability Thermal Conductivity Anisotropic Factor

Data Consistency Tests through the Use of Neural Networks and Virial Equation. Application of the Proposed Methodology to Critical Study of Density Data

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Open Journal of Physical Chemistry 2011年第3期1卷 61-69页

作者： Abdeslam hassen Meniai Serge Laugier Hakim Madani Dominique Richon 不详

This paper focuses on a very important point which consists in evaluating experimental data prior to their use for chemical process designs. Hexafluoropropylene P, ρ, T data measured at 11 temperatures from 263 to 362 K and at pressures up to 10 MPa have been examined through a consistency test presented herein and based on the use of a methodology implying both neural networks and Virial equation. Such a methodology appears as very powerful to identify erroneous data and could be conveniently handled for quick checks of databases previously to modeling through classical thermodynamic models and equations of state. As an application to liquid and vapor phase densities of hexafluoropropylene, a more reliable database is provided after removing out layer data.

关键词： Consistency Tests Hexafluoropropylene Neural Networks Vibrating Tube Densimeter Virial Equation

Nitrogen intake and utilisation pattern in the digestive tract of sheep grazing four subtropical foggages

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Nitrogen intake and utilisation pattern in the digestive tra...

Squamous Cell Carcinoma of the External Ear in a Child

ⅩⅪ International Grassland Congress and the Ⅷ International Rangeland Congress

作者： W.A van Niekerk Abubeker hassen Department of Animal and Wildlife Sciences University of PretoriaPretoria 0002South Africa

＜正＞Introduction Winter poses a critical problem in the fodder flow in many parts of South Africa due to poor nutritive value of the *** of feed in the form of hay or silage is *** excess forage can be utilised in the form of *** study compares the intake and utilisation pattern of nitrogen in sheep grazing four subtropical grass foggages.

关键词： anthephora pubescens chloris gayana digitaria eriantha foggage panicum maximum

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International Journal of Otolaryngology and Head & Neck Surgery 2015年第5期4卷 338-343页

作者： Waheed Rahman Rashid Sheikh hassen Mohammed Zeynel Abidin Dogan Department of Otorhinolaryngology and Head & Neck Surgery Hamad Medical Corporation Doha Qatar

Tumors involving the head and neck are uncommon in children. Furthermore, those which involve the external ear are extremely rare. In the external ear itself, the most commonly encountered malignancy is Squamous Cell Carcinoma, both in the adult and pediatric age groups. We encountered one such case of a 14 years old male with a recurring skin lesion involving the right external ear. In this report, we wish to highlight and address the difficulty in recognizing and managing such an unwonted pathology as Squamous Cell Carcinoma in the pediatric age group.

关键词： Squamous Cell Carcinoma External Ear External Auditory Canal

Identification and Chemical Composition of Major Camel Feed Resources in Degahbur District of Jarar Zone, Somali Regional State, Ethiopia

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Open Journal of Animal Sciences 2022年第3期12卷 366-379页

作者： Guled hassen Kawnin Abdimahad Berhan Tamir Abdihakin Ma’alin Tadele Amentie Department of Animal and Range Sciences College of Dryland Agriculture Jigjiga University Jigjiga Ethiopia Department of Animal Production College of Veterinary Medicine and Agriculture Addis Ababa University Addis Ababa Ethiopia

This study was conducted to identify major available camel feed resources and determine their chemical composition in Degahbur district. A total of 120 respondents were selected using purposive sampling technique. Data from the selected actors were collected using a semi-structured questionnaire survey, focus group discussion and field observations. The study revealed that the majority (82.5%) of the respondents in the study area were male headed households. Browsing trees and shrubs were the major available livestock feed resources both in dry (51.6%) and wet (68%) season, and followed by herbaceous species (26.6 and 23.7% for dry and wet season, respectively). The study identified about 20 herbaceous, 24 trees, 11 shrubs, 7 bush and 17 grass species which are used as camel feed in the study area. Chemical composition analyses of the sampled feeds indicated that there was a significant difference in crude protein (CP), neutral detergent fiber (NDF) and acid detergent fiber (ADF) between species in different seasons. The NDF contents in the current study were above the critical value of 60% which was reported to result in decreased voluntary feed intake, feed conversion efficiency and longer rumination time. In general, the findings indicated that the use of improved forages and agro-industrial by-products as camel was minimal;thus, camels were fed on available feed resources which are poor in nutritional quality without any supplementation. Therefore, the study suggests the need for improving camel feeding practices in the study area to enhance camel productivity.

关键词： Camel Feed Browse Species Grass Species Herbaceous

Predictive Models for the Ultimate Tensile and Yield Stresses Occurring in Joints of Untreated Friction Stir Welded 2017AA (ENAW-AlCu4MgSi) Plates

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Open Journal of Metal 2013年第2期3卷 7-18页

作者： Mohamed-Ali Rezgui Ali-Chedli Trabelsi hassen Bouzaiene Mahfoudh Ayadi Department of Mechanical Engineering Taibah University College of Engineering Yanbu Saudi Arabia Department of Mechanical Engineering University of Carthage National Engineering School of Bizerte ENIB Bizerte Tunisia UR-MSSDT (99-UR11-46) Tunis National Higher School of Engineering University of Tunis ENSIT Tunisia

Friction Stir Welding (FSW) processes have been applied in numerous industrial fields and broadly embraced by the research community. In this paper, given three FSW process parameters, namely, the tool rotation speed N (rpm), the tool traverse feed F(mm/min) and the tool pin/shoulder diameters ratio (r%), we purpose to ascertain their impact on joints Ultimate Tensile Stress (UTS) and joints Yield Stress (YS). The FSW has been executed using 6 mm thick rolled plate in 2017AA. For the design of experiments strategy, we conducted a face centered central composite strategy through which 18 trials have been executed. Then, we utilized the RSM technique to formulate the predictive models which are relevant to the (UTS) and (YS) outputs. Accordingly, the study has pointed out the prevalence of the tool rotation speed and the tool diameters ratio factors;however, the tool traverse feed (F) was found trivial and statistically insignificant. Likewise, the sensitivity analysis regarding factors N, F and r% on both (UTS) and (YS) has exhibited the dominance of the tool diameters ratio (r%), indistinctively.

关键词： Friction Stir Welding Response Surface Methodology ANOVA Sensitivity Analysis Yield Stress 2017AA

A 2.4-GHz-Low-Power CMOS RF Transmitter for IEEE 802.15.4 Standard

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Wireless Sensor Network 2012年第6期4卷 173-176页

作者： Mohen Nasri Amina Msolli Abdelhamid Helali hassen Maaref Laboratory of Micro-Optoelectronics and Nanostructures (LMON) Faculty of Sciences of Monastir Boulevard de L’environnement Monastir Tunisia

This paper presents the experimental results of a low-power RF transmitter for 2.4-GHz-band IEEE 802.15.4 standard in 0.18-μm CMOS technology. In order to make an adaptive RF transmitter, several factors must be considered. The most important factors are performances, power consumption, output power, noise factor, and cost. The RF transmitter comprises a quadrature passive mixer, and a power amplifier. The proposed RF transmitter consumes only 10.8-mW under a supply voltage of 1.8-V.

关键词： IEEE 802.15.4 Transmitter CMOS Low Cost Low Power Wireless Sensor Network

Effect of Combined Chemical Treatment on Physical, Mechanical and Chemical Properties of Posidonia Fiber

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Advances in Materials Physics and Chemistry 2016年第11期6卷 275-290页

作者： Saoussen Zannen Lassaad Ghali Mohamed Taher Halimi Mohamed Ben hassen Textile Engineering Laboratory Monastir University Monastir Tunisia Industrial Engineering Department College of Engineering Taibah University Medina Kingdom of Saudi Arabia

The aim of this study is to investigate the effect of chemical treatment method on the properties of Posidonia fibers. The chemical treatment which is carried out is a combined hydrogen peroxide and sodium hydroxide treatment. First, an investigation of the treatment processes was undertaken. Secondly, the physical properties (linear density, diameter and ratio length per diameter), the mechanical properties (tenacity, elongation) and chemical properties (FT-IR spectra and X ray diffraction) of posidonia fibers were investigated. The optimum operating conditions were identified using a factorial design.

关键词： Posidonia Fiber Combined Treatment Physical Properties Mechanical Properties Chemical Properties

Effect of Blending Ratio of Fibers on the Properties of Nonwoven Fabrics Based of Alfa Fibers

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Advances in Materials Physics and Chemistry 2014年第6期4卷 116-125页

作者： Lassaad Ghali Mohamed Taher Halimi Mohamed Ben hassen Faouzi Sakli Textile Engineering Laboratory Monastir University Monastir Tunisia

Natural fibers are nowadays increasingly employed for making nonwoven, replacing the synthetic materials due to economic and environmental considerations. In this setting, we examine the use of Alfa fibers in nonwoven. Extracted Alfa fibers present satisfying mechanical properties that allow them to be used to produce nonwoven textiles materials. Therefore, Alfa fibers are, mainly, blended with cotton, polyester, Tencel and wool. Webs are prepared using cotton or wool cards in regular width. The nonwoven consolidation is made by needle-punching method. The weight, thickness, air permeability, adiathermic capacity and tensile properties are investigated. The results exhibit that the air permeability increases with the increase of Alfa fibers ratio for the nonwoven Alfa blended with short fibers. It decreases in case of Alfa/Wool blend. We can conclude also that the nonwoven Alfa blended with wool fibers have the highest properties values for all the Alfa fibers blends. Data also revealed that the tensile properties are reduced with the increment of Alfa fibers ratio.

关键词： Alfa Fibers Nonwoven Air Permeability Specific Strength