Wave-Packet Scattering off the Kink-Solution

We investigate the propagation of a wave--packet in the $\phi^4$ model. We solve the time-dependent equation of motion for two distinct initial conditions: The wave-packet in a trivial vacuum background and in the background of the kink soliton solution. We extract the scattering matrix from the wave-packet in the kink background at very late times and compare it with the result from static potential scattering in the small amplitude approximation. We vary the size of the initial wave-packet to identify non-linear effects as, for example, the replacement of the center of the kink.Comment: 15 pages, 7 figures (from 14 eps files), 4 tables, Int. J. Mod. Phys. A, in prin

Measurements of energy loss of cosmic ray μ - mesons and protons

The aim of the work concerns the use of Conversi Counters (Neon Flash Tubes), in conjunction with a nuclear active particle spectrograph, to measure the energy loss of mesons and protons of known momentum, in the range 0.1 - 10 GeV/c. The experimental results are related to theoretical work in this field, with special reference to that of Sternheimer (1956), and Lloyd (1960).The results show that neon flash tubes are satisfactory indicators of energy loss for mesons, and their performance is in substantial agreement with expectation on the basis of the model for flash tube behaviour suggested by Lloyd (1960). The situation concerning the energy loss for protons is that the data are not sufficiently precise to allow a satisfactory comparison to be made. Some additional results have been taken from the plastic scintillator detector in the apparatus. The mean pulse amplitude from the plastic scintillator has been taken as a measure of energy loss, for mesons and protons of various momenta. Good agreement with theory has been shown for mesons. Some comparison has been outlined between the results, and the work of other authors using the same and other techniques. Results were also obtained from a water Čerenkov detector, which operated in the apparatus, to study the characteristics of Čerenkov pulse amplitude versus momentum for mesons

Groundwater studies in arid areas in Egypt using LANDSAT satellite images

Various features are interpreted which have strong bearing on groundwater in the arid environment. These include the nature of geological and lithologic units, structural lineaments, present and old drainage systems, distribution and form of water pools, geomorphologic units, weathering surfaces and other weathering phenomena, desert soils, sand dunes and dune sand accumulations, growths of natural vegetation and agriculture, and salt crusts and other expressions of salinization. There are many impressive examples which illustrate the significance of satellite image interpretation on the regional conditions of groundwater which could be traced and interconnected over several tens or even several hundreds of kilometers. This is especially true in the northern Western Desert of Egypt where ground water issuing from deep strata comes to the surface along ENE-WSW and ESE-WNW fault lines and fracture systems. Another striking example is illustrated by the occurrence of fresh to brackish groundwater on the Mediterranean Sea Coastal Zone of the Western Desert where the groundwater is found in the form of lenses floating on the saline sea water

Application of LANDSAT satellite imagery for iron ore prospecting in the Western Desert of Egypt

Prospecting for iron ore occurrences was conducted by the Remote Sensing Center in Bahariya Oasis-El Faiyum area covering some 100,000 km squared in the Western Desert of Egypt. LANDSAT-1 satellite images were utilized as the main tool in the regional prospecting of the iron ores. The delineation of the geological units and geological structure through the interpretation of the images corroborated by field observations and structural analysis led to the discovery of new iron ore occurrences in the area of investigation

Design modern structure for heterojunction quantum dot solar cells

This paper proposal new structure for improving the optical, electrical characteristics and efficiency of 3rd generation heterojunction quantum dot solar cell (HJQDSC) (ITO/CdS/QDPbS/Au) model by using the quantum dot window layer instead of bulk structure layers cell. Also, this paper presents theoretically analysis for the performance of the proposal HJQDSC (ITO/QDCdS/QDPbS/Au) structure. The new design structure was applied on traditional (SnO2/CdS/CdTe/Cu) and (ZnO/CdS/CIGS/Mo) thin film solar cells which based on sub-micro absorber layer thickness models by replacing the bulk CdTe, CIGS absorber layers and CdS window layer with quantum dot size materials to achieve higher efficiency with lesser usage layer material. Also, it has been studied the effect of using semiconductors layers in quantum dots size on electric and optical properties of thin film solar cells and the effect of window and absorber layers quantum dots radii on the performance of solar cells. Finally, a thermal efficiency analysis has been investigated for explaining the importance of new structure HJQD solar cells

Interaction of CO molecules with (Cu , Ag and Au) deposited on regular and defective MgO and BaO(001) surfaces: Density functional calculations

The adsorption properties and characteristics of CO on Cu, Ag and Au atoms deposited on various sites of the alkaline earth oxide MgO and BaO. The three members of morphological irregularities, terrace, edge, and oxygen terminated corner of MgO and BaO (001) surface have been studied by means of density functional calculations and embedded cluster model. The examined clusters were embedded in the simulated Coulomb fields that closely approximate the Madelung fields of the host surfaces. The  adsorption  properties  of  CO  have  been  analyzed  with reference  to  the  nature  of  the  oxide  support,  pairwise  and  non-pairwise  ..........Please read the full paper

Investigation of the Axial Rotor Thrust in Centrifugal Compressors استقصاء الدفع المحورى على العضور الدوار فى الضواغط النابذة

الهدف من البحث هو دراسة وتحليل والتعين الدقيق للدفع المحورى علىالعضو الدوار فى الضواغط الطاردة المرکزية. نشرح العوامل التى تؤثر علىالدفع المحورى مثل زيادة الأحمال على ضاغط ثانى أکسيد الکربون عنأوضاع التشغيل التصميمية له . کما تتضمن العوامل تأثير وجود Fouling مع الغاز مما ينتج عنه تراکم على الأسطح الداخلية لدفاعات العضو الدوارفيتسبب فى زيادة الدفع المحورى وتقليل من أداء الضاغط . يتناول البحثشرح العلاقة مابين الدفع المحورى للعضو الدوارفى وجود نسبة Foulingمع الغاز فى خلال فترة زمنية محددة من بعد عمل عمرة کاملة لضاغط ثانىأکسيد الکربون . بعد الدراسة والتحليل نقف على کيفية تقليل الدفع المحورىعلى العضو الدوار وذلک بوضع اسطوانة اتزان على العضور الدوار لخلققوى معاکسة له تتناسب مع جميع الظروف التشغيلية لضاغط ثانى أکسيدالکربون بحيث أن الدفع المحورى للعضو الدوار بعدها لا يتعدى 50 % منحمل الکرسى. النتائج النهائية التى تم الحصول عليها: عند استخدام قطراسطوانة اتزان = 158.6686 mmt D تکون أعلى قيمة للدفع المحورى عنأوضاع التشغيل المختلفة للضاغط هى 93.193 % من حمل الکرسى. عنداستخدام قطر اسطوانة اتزان = 186.065 mmt D تکون أعلى قيمة للدفعالمحورى عن أوضاع التشغيل المختلفة للضاغط هى 73.35 % من حملالکرسى. عند استخدام قطر اسطوانة اتزان = 174.595 mmt D تکونأعلى قيمة للدفع المحورى عن أوضاع التشغيل المختلفة للضاغط هى41.22 % من حمل الکرسى مع وجود Fouling مع الغاز وعند أقصى حملللضاغط بعد العمرة فى عدم وجود Fouling مع الغازهى 0 % من حملالکرسى وهذا يعتبرأنسب قطر يستخدم لاسطوانة الاتزان (Balance drum)لان الدفع المحورى يکون أقل من % 50 من حمل الکرسى.Abstract: This article is a study, analysis, and determine accurately the axial rotor thrust for centrifugal compressors. Are explained the factors that affect axial rotor for carbon dioxide compressor during operating conditions. Also, the effect of the existence of fouling with gas, results in the accumulation of fouling on the internal surfaces of the impellers leading to an increase in axial rotor thrust and reduction of the performance of the compressor. The relationship between axial rotor thrust and fouling ratio with time is discussed after complete overhaul for the carbon dioxide compressor. The axial rotor thrust on the carbon dioxide compressor is reduced by placing balance drum on rotor of the compressor in the opposite direction of the axial force which is suitable for all operating conditions of the compressor. The resultant axial force didn’t exceed 50 % of rated bearing load, and the analysis method is then approved to be effective. The residual thrust load for high pressure rotor for the compressor before modification at design operating condition is equal to 13.68 % of rated bearing load, while at the high load without fouling effect for the compressor is equal to 58.47 % of rated bearing load and compressor with fouling effect is equal to 110.9 % of rated bearing load. When using the balance drum diameter Dt =158.6686 mm, the highest value of axial thrust force is equal to 93.193 % of rated bearing load. When using the balance drum diameter Dt =174.595 mm, the highest value of axial thrust force is equal to 41.22 % of rated bearing load. When using the balance drum diameter Dt =186.065 mm, the highest value of axial thrust force is equal to 73.35 % of rated bearing load

Efficient Catalytic Production Of Biodiesel Using Nano-sized Sugar Beet Agro-industrial Waste

This paper addresses the use of agro-industrial residue as a promising heterogeneous catalyst for the efficient production of biodiesel. That is, CaO-rich Sugarbeet agro-industrial waste (smashed down to nano-size) shows superb catalytic activity for biodiesel production via transesterification process employing sunflower oil and methanol. Physicochemical properties of the proposed catalyst are probed by TGA–DTG, XRF, XRD, FT-IR, SEM, BET, and CO2-TPD techniques. Biodiesel conversion (%) of Ca. 93% is achieved under the optimal conditions (catalyst loading of 1 wt%, methanol/oil molar ratio of 4.5:1, refluxed at 75 °C for 60 min). The relatively short reaction time indicates the enhanced kinetics of the process using the proposed agro-industrial residue which imparts its economic feasibility. Also, the proposed CaO-rich residue can be reused twice while retaining its catalytic activity. The thus-produced biodiesel fuel compiles the ASTM D6751 and EN-14214 specifications