Detailed field mapping of a 120-km-long segment of the northwestern Red Sea margin reveals the existence of a number of sediment-input sites where Lower Miocene sediments form coarse-grained fan delta systems. Localizations of the fan deltas at the sediment-input sites (Wadis Gassus, Guesis, Quwyh and Sharm El Bahari) are controlled by structural and topographic elements, including relay ramps between interacting normal fault segments, cross-trend transfer faults, reactivated Precambrian basement fabrics and the plunge directions of tilted fault blocks. Sedimentary facies and geometrical characteristics of the fan deltas indicate that they are progradational and “Gilbert-type” fan delta systems. Variations in size and composition of the conglomerate clasts reflect the heterogeneous lithologies of the Precambrian basement and pre-rift strata in the source areas along the rift margin. Palaeocurrent data show marked changes in paleoflow directions, from northeast in the northernmost fans to east and southeast directions in the southern fans. This change occurs across the Duwi accommodation zone which formed a topographic high separating the oppositely dipping half-grabens in the study area. The data presented in this paper clearly demonstrates that the structural architecture of the northwestern Red Sea margin together with its related topographic expressions played a fundamental role in controlling the drainage network systems, sediment dispersal and localization of the fan deltas in this part of the rift system.

This work studies the influence of plasma-activated water (PAW) on the decontamination of beef and its influence on the color, pH, the thiobarbituric acid reactive substance values (TBARS), and total volatile basic nitrogen (TVBN) values of meat. PAW was generated using non-thermal atmospheric pressure plasma jet (NTAPPJ). He + 0.2% N 2 and He + 0.2% O 2 were used as worker gas to generate PAW. The PAW produced by the He + O 2 plasma system exhibited a higher potential for decontamination of beef than that produced by the He + N 2 plasma system. The lightness value ( L *) of treated beef does not exhibit a noticeable difference with the control one. TBARS values of all treated beef were lower than the rancidity threshold but significantly greater than that of control samples. The TVBN value of control beef samples reached the decay threshold after 18 days of stockpiling, but treated beef remained good. This work reveals that PAW can potentially inhibit the growth of microorganisms in beef.

The Red Sea and Gulf of Aden constitute parts of the Afro-Arabian rift systemthat are in themost advanced stages of continental break-up. These basins have therefore received extensive scrutiny in the geoscientific literature, but several aspects of their evolution remain enigmatic. Many of their most important features lie beneath several kilometers of water, in places covered by several kilometers of evaporite deposits, and along international political boundaries. All these factors greatly complicate the acquisition and interpretation of both subsurface wellbore and geophysical datasets. Much of our understanding of the evolution of the Red Sea has therefore relied on the integration of outcrop geology and land-based analytical studies with these more difficult to obtain marine observations. While stratigraphic, radiometric and structural data indicate that extension and rifting initiated in the southern Red Sea during the LateOligocene (similar to 28-25 Ma), the start of rifting in the northern Red Sea is more difficult to constrain due to paucity of rift-related volcanismand reliable biostratigraphy of the oldest syn-kinematic sedimentary strata. A regionalNW-SE trending alkali basalt dike swarm, with associated extensive basalt flows in the vicinity of Cairo, appears to mark the onset of crustal-scale extension and continental rifting. These dikes and scarce local flows, erupted at the Oligocene-Miocene transition (similar to 23 Ma) and coeval with similar trending dikes along the Yemen and Saudi Arabian Red Sea margin, are interbedded with the oldest part of the paleontologically dated siliciclastic syn-rift stratigraphic section (Aquitanian Nukhul Fm.), and are associated with the oldest recognized extensional faulting in the Red Sea. Bedrock thermochronometric results from the Gulf of Suez and bothmargins of the Red Sea also point to a latest Oligocene onset of major normal faulting and rift flank exhumation and large-magnitude early Miocene extension along the entire length of theRed Sea rift. This early phase of rifting along the Egyptian Red Seamargin and in theGulf of Suez resulted in the formation of a complex, discontinuous fault pattern with very high rates of fault block rotation. The rift was segmented into distinct sub-basins with alternating regional dip domains separated by well-defined accommodation zones. Sedimentary facies were laterally and vertically complex and dominated by marginal to shallowmarine siliciclastics of the Abu Zenima, Nukhul and Nakheil Formations. Neotethyan faunas appeared throughout all of the sub-basins at this time. During the Early Burdigalian (similar to 20 Ma) tectonically-driven subsidence accelerated and was accompanied by a concordant increase in the denudation and uplift of the rift shoulders. The intra-rift fault networks coalesced into through-going structures and fault movement became progressively more focused along the rift axis. This reconfiguration of the rift structure resulted in more laterally continuous depositional facies and the preponderance of moderate-to-deep marine deposits of the Rudeis, Kareem and Ranga Formations. The early part of the Middle Miocene (similar to 14 Ma) was marked by dramatic changes in rift kinematics and sedimentary depositional environments in the Red Sea and Gulf of Suez. The onset of the left-lateral Gulf of Aqaba transform fault system, isolating the Gulf of Suez from the active northern Red Sea rift, resulted in a switch from orthogonal to oblique rifting and to hyperextension in the northern Red Sea. The open marine seaway was replaced by an extensive evaporitic basin along the entire length of the rift from the central Gulf of Suez to Yemen/Eritrea. In Egypt these evaporites are ascribed to the Belayim, South Gharib, Zeit and Abu Dabbab Formations. Evaporite deposition continued to dominate in the Red Sea until the end of the Miocene (similar to 5 Ma) when a subaerial unconformity developed across most of the basin. With the onset of seafloor spreading in the southern Red Sea, Indian Ocean marine waters re-entered through the Bab el Mandab in the earliest Pliocene and re-established open marine conditions. During the Pleistocene, glacial-isostatic driven sea-level changes resulted in the formation of numerous coral terraces and wave-cut benches around the margins of the Red Sea, Gulf of Suez and Gulf of Aqaba. Their present elevations suggest that the Egyptian Red Sea margin has been relatively vertically stable since the Late Pleistocene. While there is general agreement that full seafloor spreading, producingwell-definedmagnetic stripes, has been occurring in the southern Red Sea since similar to 5 Ma, there is ongoing debatewhether andwhen lithospheric break-up has occurred in the northern Red Sea. Industry wellbore and seismic data demonstrate that continental crust extends at least several tens of kilometers offshore from the present-day coastline, and that the northernRed Sea is a non-volcanic rifted-margin. On the basis of integrated geophysical, petrological, geochemical and geological datasets, we contend that true, laterally integrated sea-floor spreading is not yet manifest in the northern Red Sea.

A helium cold atmospheric pressure plasma jet (HCAPPJ) driven by a commercial neon power supply was designed and utilized for inactivation bacteria. The generated reactive spices by HCAPPJ were investigated by optical emission spectroscopy. The reactive species of OH, OI, OI, N 2 1+ , N 2 1+ and He were identified in the UV–Vis wavelength region. The reactive species was not detected between 200 nm and 300 nm, as the flow rate of helium gas increased that led to the plasma temperature reducing to a value near to the room temperature. In this work, we studied the impact of HCAPPJ on Gram-positive and Gram-negative bacteria. The survival amounts of the two types of bacteria were decreased vastly when the rate flow rate was equal to 10 L/min.

AISI 304 austenitic substrates with different thicknesses were treated using rf plasma nitriding. This is to study the influence of the temperature gradient on the surface properties of the treated samples including nitrogen diffusivity and microstructure. X-ray diffraction, optical microscopy and scanning electron microscopy were used to characterize the treated samples. The results revealed that the surface temperature and temperature gradient of the nitrided substrate are substrate thickness dependent. It was found that the thickness of nitrided samples increases substantially as the temperature gradient increases from 1.93 x 10 5 to 10x10 5o C/m. The microstructure is characterized mainly by the nitride phases of nitrogen expanded austenite (γN) and chromium nitride (CrN). Furthermore, the iron nitride phase of Fe4N is detected at temperature gradient of 4.1x10 5o C/m and lower. A maximum value of the nitriding rate of 1.21 μm 2 /s have been observed with the temperature gradient of 10x10 5o C/m. Keywords—Temperature gradient, AISI 304 stainless steel, rf plasma nitriding, surface morphology.

Nickel-titanium (Ni-Ti) shape memory alloys (SMAs) are attractive materials for orthopedic and dental implants, due to its two intrinsic properties including shape memory effect (SME) and superelasticity (SE), which may not be found in other commonly- used surgical metals. Possible Ni ion release, however, hampers their medical applications, particularly in orthopedic implants where fretting is always expected at the articulating surface. Inductively coupled radio frequency plasma (ICRFP) was employed to alter the surface of equiatomic Ni-Ti discs in order to create a barrier to out-diffusion of Ni ions from the bulk material. The ICRFP experiments were carried out with nitrogen, which promoted the formation of a titanium nitride layer on the surface of the Ni-Ti samples. The present paper explores the biocompatibility and performance of the ICRFP treated and untreated Ni-Ti samples. The results confirm that nitrogen plasma modified Ni-Ti alloys are potentially suitable materials for orthopedics without inducing harmful biological effects.

The Sinai hinge belt is a major crustal boundary in northern Sinai separating different tectonic terranes. This boundary started as a number of ENE–WSW-oriented faults of Precambrian or Palaeozoic age and played a major role in the Mesozoic and Cenozoic tectonic evolution of NE Africa. The Sinai hinge belt was reactivated by normal faulting during Early Mesozoic opening of Neotethys and was later reactivated by dextral transpression during Late Cretaceous–Early Tertiary closure of Neotethys and dextral transtension in the Miocene. This study highlights the structural characteristics of the hinge belt and the nature of deformation of its fault segments. It also highlights the role of this basement structure as a crustal boundary between terranes of different tectonic settings as well as its relationship to the structural development of the nearby areas in NE Africa. Supplementary material: A Google Earth image and structural form-line map of Rishat Saada Fault, Google Earth image and Landsat TM image of Rishat Lehman Fault and G. Ras Ebeid, geological map of El Risha El Hamra Fault, Landsat TM image and structural form-line map of the Burqa–Riash Fault, and Google Earth image and geological map of El Bruk Fault are available at www.geolsoc.org.uk/SUP18697.

Nickel titanium (NiTi) alloys are potentially useful in biomedical applications due to their unique superelasticity behaviour and shape memory effects (SME). However, these alloys are vulnerable to surface corrosion and the most serious issue is outdiffusion of toxic Ni ions from the substrate into body tissues and fluids. Hence, it is necessary to produce a surface barrier to impede the out-diffusion of Ni ions from the alloys. The inductively coupled radio frequency plasma (ICRFP) is an efficient technique for modifying the surfaces of NiTi alloys. The results exhibit the enhancement of the corrosion resistance and tribological properties of the NiTi substrate, but also effectively suppress the Ni ions release from the substrate. All these improvements can be attributed to the formation of titanium nitride (TiN) on the surface of NiTi alloys. KeywordsNickel Titanium (NiTi); Superelasticity; Shape Memory Effect SME; Inductively Coupled Radio Frequency Plasma (ICRFP); Corrosion Resistance; Fraction Coefficient

We report here on the effect of annealing time, in air and at 800°C for time periods of (6-30 h), on the fluctuation induced excess conductivity ∆σ in Bi2-xPbx: 2223 superconductors with various x values. The logarithmic plots of ∆σ and the reduced temperature e reveal three different exponents corresponding to two different crossover temperatures in the slope of each plot. The first exponent in the normal region is at a temperature of (Tc^(mf) ＜＜ T ＜ 2Tc ^(mf) ) and its values are close 2.5, in which the order parameter dimensionality (OPD) is not 0D. The second exponent is at a temperature of T ＞ Tc^(mf) , and its values are close to 1, in which the OPD is 2D. The third exponent is in the critical-field region at a temperature of (Tc ＜ T ≤ Tc^(mf)), and its values are close to 0.5, in which the OPD is 3D. Furthermore, the interlayer coupling J, Ginzburg-Landau coherence length ζc(0), temperature width (To-T^c(mf)), and resistivity slope (dp/dT) are also calculated for the two examined samples, and their values are affected by changing both the annealing time and Pb content. Our results are discussed in terms of the correlation between the carrier concentration and volume fraction of the high Tc phase for the considered samples.

Powder compacts of the system Bi2–xPbxSr2Ca2Cu3Oy with 0 ≤ x ≤ 0.5 molar ratio using both techniques; isothermal hot pressing and the solid state reaction (sintering). The XRD of the hot pressed powder compacts of the nominal compositions Bi2–xPbxSr2Ca2Cu3Oy showed 2212 and 2223 phases. The resistivity temperature variations belonging to the composition Bi1.8Pb0.2Sr2Ca2Cu3Oy showed metal-superconducting transition at Tons = 143 K for the annealed sample for 24 h. The annealed nominal composition Bi1.5Pb0.5Sr2Ca2Cu3Oy for 18 h showed metal to superconducting transition at 80 K.

The influences of (isothermal hot pressing-doping) treatment on the microstructure, electrical and mechanical properties of Bi2Sr3-xCaxCu2O8+δ (BSCCO), x ranging from 0.0 to 2 are assessed. BSCCO pellets were prepared by isothermal hot pressing (IHP) technique. The experimental works in this study consists of dc electrical resistivity measurements for electrical and superconducting properties, microhardness tests for mechanical characteristics, powder x-ray diffraction (XRD) for phase analyses (phase ratio), differential thermal analysis (DTA) for melting behaviour and scanning electron microscopy (SEM) for microstructure investigations. The results indicated that the Ca2+ doping and isothermal hot pressing increased significantly the superconducting transition temperature (Toc), which promotes the formation of high-Tc phase. Additionally, Vickers microhardness (VHN), Young's modulus, fracture toughness, brittleness index and elastic stiffness coefficient were also improved. Moreover, IHP-Doping improved the microstructure and the density of the BSCCO studied samples. Microhardness was found to be load dependent. Otherwise, we evaluated the load independent hardness, Young's modulus, fracture toughness and brittleness index of BSCCO samples. The possible reasons for the observed enhancement in electrical and mechanical properties due to (i) the homogeneity of grain region distribution (ii) the enhancement of superconducting phases.

As the cost of energy and hence the cost of producing Portland cement increase, the question arises as to whether we are obtaining optimum performance from the admixtures we use. As an example, data are presented indicating that a significant improvement in strength and shrinkage can be achieved by optimizing the sulfate content of the cement for given cement–admixture combinations. It is shown that the optimum SO3 is clearly a function of the initial temperature of the concrete, particularly during the first 24 h after casting, a characteristic of considerable importance in hot weather concreting and steam curing of concrete products. It is recommended that more attention be directed towards optimizing the effectiveness of chemical admixtures in both the ready-mixed concrete and precast concrete industries.

Carbonitriding of AISI 304 austenitic stainless steel was performed at a plasma-processing power of 450 W using inductively coupled radio frequency (rf) plasma in a gas mixture of 50% N2 and 50% C2H2. The rate of carbonitriding, microhardness, phase structure of the compound layer, surface microstructure and cross-section morphology were studied before and after the annealing process. At the annealing temperature up to 800°C, the microhardness values of the compound zones decrease, while the associated values of the diffused zones increase. Little change was found in the thickness of the compound and diffused zones when the carbonitrided samples were annealed up to 400°C. However, at a higher annealing temperature, the thicknesses of both zones increase. The γ-Fe austenite is the main crystalline phase that can be detected by X-ray diffraction. As the annealing temperature increases up to 500°C, X-ray spectra show α-Fe and Fe5C2 phases. Nitrogen diffuses more deeply from the near surface to the interior of the treated sample as the annealing temperature increases up to 800°C and this might explain the extent of carbonitrided thickness and the enhanced microhardness of the diffused zone.

The nitriding behavior of cold rolled Fe93Ni4Ti3 specimens was compared with that of hot rolled specimens of the same materials. Radio frequency (rf) nitriding was performed for 10 minutes in a 10-2 mbar nitrogen atmosphere. The continuous plasma power was varied from 300-550 W in steps 50 W or less. Results of optical microscopy (OM), x-ray diffraction (XRD) and microhardness measurements (Hv) are presented and discussed with regard to the influence of kind rolling on the nitriding behavior, particularly nitride formation and nitride layer growth on mechanical properties. The results show a remarkable increase of nitrogen diffusivity and microhardness of cold rolled nitride samples. These best results may be attributed to enhancement of the defect and/or a compressive stress.

Experiments were performed with an aim of studying the effect of hot-rolled temperature (600 and 900°C) on radio frequency (rf) plasma nitriding of Fe93Ni4Zr3 alloy. Nitriding was carried out for 10 min in a nitrogen atmosphere at a base pressure of 10−2 mbarr. Different continuous plasma processing powers of 300–550 W in steps 50 W or less were applied. Nitrided hot-rolled specimens were characterized by optical microscopy (OM), X-ray diffraction (XRD) and microhardness measurements. The results reveal that the surface of hot-rolled rf plasma nitrided specimens at 600°C is characterized with a fine microstructure as a result of the high nitrogen solubility and diffusivity. Moreover, the hot-rolled treated samples at 600°C exhibit higher microhardness value than the associated values of hot-rolled treated samples at 900°C. The enhancement of microhardness is due to precipitation and predominance of new phases (γ and ε phases). Mainly, this conclusion has been attributed to the high defect densities and small grain sizes of the samples hot-rolled at 600°C. Generally, the refinement of grain size plays a dramatic role in improvement of mechanical properties of tested samples.

Laser Induced Breakdown Spectroscopy (LIBS) is a well known spectrochemical elemental analysis technique. In our investigations of the LIBS spectra it has been found that there is a remarkable correlation between the ionic to atomic spectral lines emission ratio and the surface hardness of solid targets. This phenomenon is related to the repulsive force of the laser induced shockwaves. The present study revealed a confirmation of the above mentioned correlation and the interpretation of the phenomenon in view of the laser induced shockwaves velocity has been also proved experimentally. The relation between the target surface hardness and the ionic to atomic spectral lines intensity ratio of Zr in specially prepared steel alloys treated thermally to have different surface hardness, has been estimated via LIBS. The obtained LIBS spectra have been used to obtain I-ionic/I-atomic for certain spectral lines of minor elements in the investigated alloys. The obtained linear relation between the steel samples surface hardness (measured mechanically) and the spectral lines ratio confirm the same effect.The above investigations open the door for LIBS to be exploited not only as a spectrochemical analytical technique but also as an easy way to measure the surface hardness of solid targets.

Samples of pure titanium were laser nitrided by continuous wave CO2 laser irradiation in mixtures of nitrogen and argon gas with different ratios. In all cases, TiN formed in the surface. The properties and the characteristics of the processed samples were evaluated using a nanoindentation technique, optical microscopy, surface roughness measurements, x-ray diffraction and wear resistance measurements. It was found that the nitrogen content in the gas atmosphere has a massive effect on the microstructure and the mechanical properties of the laser nitrided samples. For all treated samples, the mechanical properties improve with the nitrogen content in the gas atmosphere. Moreover, the thickest TiN layers with high values of the microhardness and good wear resistance were obtained for the titanium sample that was treated in 80% N-2 and 20% Ar. In addition, the strain and the grain size of the coatings formed at the surface of the laser nitrided titanium samples were determined from x-ray data.

The rf plasma carbonitriding of AISI-304 austenitic stainless steel was examined as a function of plasma time. The properties of the carbonitrided layer were determined using optical microscopy, scanning electron microscopy, X-ray diffraction and microhardness testing. For the sample treated for 10 min, the rate of carbonitriding was calculated to be ∼0.5 μm2/s. The surface hardness of the carbonitrided layer processed for 10 min was 1715 Hv, 0.1 as compared to 228 Hv, 0.1 for the untreated surface. The high rate of carbonitriding and the excellent microhardness of the compound layer have been explained in terms of nitrogen and carbon concentration gradients, microcracks formed in the surface during the plasma process and temperature gradients.

The present work reports on the effect of input plasma processing power in the range of 350–650W on the microstructure and mechanical properties of plasma nitrided Ti. The plasma processing time was 20min and a gas mixture of 15% C2H2 and 85% N2 was used. The characteristics of the carbonitrided layer have been investigated by microhardness measurements, surface roughness measurements, optical microscopy, and X-ray diffraction. The measured surface hardness values of the compound layer shows a maximum of 2050HV0.1 for the sample treated at a plasma power of 550W. The thickness of the carbonitrided layer continuously increases as the plasma power increases. Moreover, the highest carbonitriding rate of 3.52μm2/s was observed when the input plasma power was adjusted at 600W. This high carbonitriding rate of treated titanium samples is ascribed to the high concentration of active carbon and nitrogen species in the plasma atmosphere and the formed microcracks in the near surface of the sample during the plasma processing.