717 research outputs found
Sustainable machining of Ti-6Al-4V using cryogenic cooling: an optimized approach
Abstract Cryogenic machining is an effective, sustainable cooling approach in machining hard-to-cut materials. In this work, two multi-objective optimization techniques, namely; non-dominated sorting genetic algorithm, and grey relational analysis, were used to optimize the cutting performance during turning Ti-6Al-4V alloys under flood and cryogenic cooling. The machining performance was optimized in terms of surface roughness, material removal rate, tool performance and cutting forces. The optimal solutions, including cutting conditions and cooling technique, were determined for different machining strategies (i.e. roughing, finishing, and productivity). It was found that cryogenic cooling offers better cutting performance with a higher optimization index than flood approach
Hadron Production in Neutrino-Nucleon Interactions at High Energies
The multi-particle production at high energy neutrino- nucleon collisions are
investigated through the analysis of the data of the experiment CERN-WA-025 at
neutrino energy less than 260GeV and the experiments FNAL-616 and FNAL-701 at
energy range 120-250 GeV. The general features of these experiments are used as
base to build a hypothetical model that views the reaction by a Feynman diagram
of two vertices. The first of which concerns the weak interaction between the
neutrino and the quark constituents of the nucleon. At the second vertex, a
strong color field is assumed to play the role of particle production, which
depend on the momentum transferred from the first vertex. The wave function of
the nucleon quarks are determined using the variation method and relevant
boundary conditions are applied to calculate the deep inelastic cross sections
of the virtual diagram.Comment: 6 pages PDF forma
Biostimulation and reproductive performance of artificially inseminated rabbit does (Oryctolagus cuniculus)
[EN] Biostimulation is a non-hormonal and practical technique that has not yet been widely utilised when applied immediately before insemination to improve reproductive efficiency in livestock species. This study was conducted to determine the influence of short-term male biostimulation on behavioural and reproductive performance of inseminated rabbit does. A total of 142 female New Zealand White rabbits were randomly assigned to 3 groups. Females were either exposed to male odour (Odour group) or an adult aproned male (Male group), while the remaining does that were neither exposed to the male odour nor the adult male are considered the control group. All females were inseminated after the 2 h exposure session. Conception rates were determined by abdominal palpation 12 d after insemination. The results showed that conception rate of the male odour group (79.59%) was greater than that of male presence group (76.09%) and that of the control group (68.09%). Moreover, biostimulated does showed significant behavioural activities during the 2 h exposure session compared to the control group. Although no significant differences were recognised, litter size at birth and at weaning was slightly increased in biostimulated compared to control females. Nor were there any significant difference in serum oestradiol concentrations between treated groups. Conclusively, short-term 2 h biostimulation of rabbit does resulted in the appearance of various behavioural responses followed by differences in conception rates between groups after routine artificial insemination.El-Azzazi, FE.; Hegab, IM.; Hanafy, AM. (2017). Biostimulation and reproductive performance of artificially inseminated rabbit does (Oryctolagus cuniculus). World Rabbit Science. 25(4):313-321. doi:10.4995/wrs.2017.7446SWORD31332125
Facies analysis, glauconite distribution and sequence stratigraphy of the middle Eocene Qarara Formation, El-Minya area, Egypt
AbstractThe Qarara Formation consists mainly of shale at the base and overlain by limestone at the top. The formation is Middle Eocene (Lutetian) in age. Three sections located at the eastern bank of the Nile River in El-Minya Province have been measured, described, and sampled. These sections from north to south are: Gebel Qarara, El-Sheikh Fadl, and Gebel El-Ahmar.The main microfacies identified in the studied sections are: silty claystone, silty shale, fossiliferous glauconite, glauconitic (green) sand, glauconitic fossiliferous ironstone, glauconitic bioclastic wacke-packstone, glauconitic bioclastic lime-mudstone-wackestone. These microfacies have been deposited in shallow open marine environment.Collectively the studied rocks contain two principal facies: lower argillaceous facies and upper carbonate facies that separated by glauconitic fossiliferous ironstone bed. The lower argillaceous part represents highstand systems tract (HST), whereas the upper carbonate part represents transgressive systems tract (TST). The glauconitic fossiliferous ironstone bed is recognized as a sequence boundary (SB)
A novel fabrication approach for multifunctional graphene-based thin film nano-composite membranes with enhanced desalination and antibacterial characteristics
A practical fabrication technique is presented to tackle the trade-off between the water flux and salt rejection of thin film composite (TFC) reverse osmosis (RO) membranes through controlled creation of a thinner active selective polyamide (PA) layer. The new thin film nano-composite (TFNC) RO membranes were synthesized with multifunctional poly tannic acid-functionalized graphene oxide nanosheets (pTA-f-GO) embedded in its PA thin active layer, which is produced through interfacial polymerization. The incorporation of pTA-f-GOL into the fabricated TFNC membranes resulted in a thinner PA layer with lower roughness and higher hydrophilicity compared to pristine membrane. These properties enhanced both the membrane water flux (improved by 40%) and salt rejection (increased by 8%) of the TFNC membrane. Furthermore, the incorporation of biocidal pTA-f-GO nanosheets into the PA active layer contributed to improving the antibacterial properties by 80%, compared to pristine membrane. The fabrication of the pTA-f-GO nanosheets embedded in the PA layer presented in this study is a very practical, scalable and generic process that can potentially be applied in different types of separation membranes resulting in less energy consumption, increased cost-efficiency and improved performance.Hanaa M. Hegab, Ahmed ElMekawy, Thomas G. Barclay, Andrew Michelmore, Linda Zou, Dusan Losic, Christopher P. Saint and Milena Ginic-Markovi
Comparative evaluation of surface quality, tool wear, and specific cutting energy for wiper and conventional carbide inserts in hard turning of aisi 4340 alloy steel
This paper presents an experimental study into the comparative response of wiper and round-nose conventional carbide inserts coated with TiCN + ALO + TiN when turning an AISI 4340 steel alloy. The optimal process parameters, as identified by pre-experiments, were used for both types of inserts to determine the machined surface quality, tool wear, and specific cutting energy for different cutting lengths. The wiper inserts provided a substantial improvement in the attainable surface quality compared with the results obtained using conventional inserts under optimal cutting conditions for the entire range of the machined lengths. In addition, the conventional inserts showed a dramatic increase in roughness with an increased length of the cut, while the wiper inserts showed only a minor increase for the same length of cut. A scanning electron microscope was used to examine the wear for both types of inserts. Conventional inserts showed higher trends for both the average and maximum flank wear with cutting length compared to the wiper inserts, except for lengths of 200–400 mm, where conventional inserts showed less average flank wear. A higher accumulation of deposited chips was observed on the flank face of the wiper inserts than the conventional inserts. The experimental results demonstrated that edge chipping was the chief tool wear mechanism on the rake face for both types of insert, with more edge chipping observed in the case of the conventional inserts than the wiper inserts, with negligible evidence of crater wear in either case. The wiper inserts were shown to have a higher specific cutting energy than those detected with conventional inserts. This was attributed to (i) the irregular nose feature of the wiper inserts differing from the simpler round nose geometry of the conventional inserts and (ii) a higher tendency of chip accumulation on the wiper inserts
GROWTH PARAMETERS, IRRIGATION REQUIREMENTS AND PRODUCTIVITY OF MAIZE IN RELATION TO SOWING DATES UNDER NORTH-DELTA OF EGYPT CONDITIONS
Field experiments were conducted in El-Bosaily farm in the Northern Coastal of Egypt during summer seasons of 2015 and 2016 to study the response of the single Cross 10 maize (Zea mays L.) hybrid to three sowing dates (1st of May, 1st of June and 1st of July) and three levels of irrigation; 60%, 80% and 100% of irrigation requirements (IR) which applied by drip irrigation system. The experimental design was split plot with four replications where the sowing dates and the irrigation levels were located in the main plots and the sub-plots, respectively. Germination percentage, vegetative growth, indices yield and yield components and water use efficiency were compared under the various sowing dates and irrigation level treatments. The main results were as follows: Vegetative growth traits, yield and water use efficiency of maize were decreased as sowing date delayed beyond the 1st of May. Sowing maize seeds at 1st of July gave the lowest vegetative growth traits and productivity compared to the other sowing dates during both seasons. Meanwhile application of 60% (IR) decreased vegetative growth traits as well as grain yield. Nevertheless, the 100% (IR) irrigation treatments gave the highest vegetative traits and grain yield. In contrary, results showed that the 60% (IR) irrigation requirement gave the highest water use efficiency (WUE). Increasing irrigation water above 60% (IR) led to decrease the values of water use efficiency. Meanwhile, the highest water use efficiency was obtained from the first sowing date (1st May) followed by the second sowing date (1st June) while the lowest value was obtained by the third sowing date (1st July)
Geological and Geotechnical Assessment of Gabal Ataqa Dolostones, for Pavement Construction in Egypt
Aggregate is a collective term for the mineral materials such as sand, gravel and crushed stone. By weight, aggregate generally occupies about 92-96 percent of the hot mix asphalt (HMA), and about 79-85 percent of the Portland cement concrete (PCC). Aggregate is also used for Base and Sub-base courses for both flexible and rigid pavements. This research aims to investigate the geological and geotechnical properties of Gabal Ataqa dolostone for pavement construction projects in Egypt. A total of six dolomite microfacies were recognized and classified according to the dolomite rock classification. The X-Ray Diffraction (XRD) analysis showed that Ataqa dolostones consist mainly of dolomite (89.79%) and calcite (7.74%), while quartz (2.3 %) and halite (0.18 %) were found in small amounts in some samples. Generally Ataqa dolostone is around stoichiometric (50.96%), and may belong to dolomite of late diagentic coarse crystalline dolomite. The chemical investigation showed that the major elements of the investigated dolostone rocks are SiO2 (1.72 %); CaO (32.03%), MgO (19.18%), Fe2O3 (0.22 %), Na2O (0.11%), and Al2O3 (0.05%) while the loss on ignition is about (46.19 %.). The trace elements consist of strontium (116 ppm), barium (14.0 ppm); and very low amount of zirconium (3 ppm). Petrographic, chemical, mineralogical, and compressive strength of Ataqa dolostone rocks beside, geotechnical properties of the produced coarse aggregates were investigated. Los Angeles abrasion, apparent specific gravity, water absorption, disintegration, and stripping were evaluated. The results of the conducted testing indicate that Ataqa dolostone rocks are suitable for road construction and concrete industry.
Inclusive production of charged pions in p+C collisions at 158 GeV/c beam momentum
The production of charged pions in minimum bias p+C interactions is studied
using a sample of 377000 inelastic events obtained with the NA49 detector at
the CERN SPS at 158 GeV/c beam momentum. The data cover a phase space area
ranging from 0 to 1.8 GeV/c in transverse momentum and from -0.1 to 0.5 in
Feynman x. Inclusive invariant cross sections are given on a grid of 270 bins
per charge thus offering for the first time a dense coverage of the projectile
hemisphere and of the cross-over region into the target fragmentation zone.Comment: 31 pages, 30 figures, submitted to European Journal of Physic
Conserved peptides within the E2 region of Hepatitis C virus induce humoral and cellular responses in goats
The reason(s) why human antibodies raised against hepatitis C virus (HCV) E2 epitopes do not offer protection against multiple viral infections may be related to either genetic variations among viral strains particularly within the hypervariable region-1 (HVR-1), low titers of anti E2 antibodies or interference of non neutralizing antibodies with the function of neutralizing antibodies. This study was designed to assess the immunogenic properties of genetically conserved peptides derived from the C-terminal region of HVR-1 as potential therapeutic and/or prophylactic vaccines against HCV infection. Goats immunized with E2-conserved synthetic peptides termed p36 (a.a 430–446), p37(a.a 517–531) and p38 (a.a 412–419) generated high titers of anti-p36, anti-p37 and anti-P38 antibody responses of which only anti- p37 and anti- p38 were neutralizing to HCV particles in sera from patients infected predominantly with genotype 4a. On the other hand anti-p36 exhibited weak viral neutralization capacity on the same samples. Animals super-immunized with single epitopes generated 2 to 4.5 fold higher titers than similar antibodies produced in chronic HCV patients. Also the studied peptides elicited approximately 3 fold increase in cell proliferation of specific antibody-secreting peripheral blood mononuclear cells (PBMC) from immunized goats. These results indicate that, besides E1 derived peptide p35 (a.a 315–323) described previously by this laboratory, E2 conserved peptides p37 and p38 represent essential components of a candidate peptide vaccine against HCV infection
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