Al-Mustansiriyah Journal of Science

In the last few years, and due to the vast widespread of social media applications, texts have become more important and get more attention. Since texts, in general,are carrying a lot of information, that can be extracted and analyzed. Several researchers have done significant works in text classification. Within different scripts such as English and other western languages, several challenges and obstacles have beenaddressed with such a field of research. Regarding the Arabic language, the process is different from other vital languages since Arabic is considered an orthographic language that depends on the word shape. It is not easy to apply the standard text preprocessing techniques since it affects the word meaning. This paper evaluates Arabic short text classification using three standard Naïve Bayes classifiers. In our method, we classify the thesis and dissertations using their titles to perform the classification process. The collected dataset is collected from different repositories by using standard scrapping techniques. Our method classifies the document based on their titles to be placed in the desired specialization. Several preprocessing techniques have been applied, such as (punctuation removal, stop words removal, and space vectorization). For feature extraction, we adopt the TF-IDF method. We implemented three types of Naïve Bayes classifiers, which are (Multinomial Naïve Bayes, Complemented Naïve Bayes, and Gaussian Naïve Bayes). The study results showed that Complemented Naïve Bayes Classifier proposed the best performance with (0.84) of accuracy for the testing phase. The results of the study are promising to be applied with different short text classifications.

The aim of this paper is to study Z-transform to solve non-linear difference equations, after converting them to linear difference equations by one of the conversion methods. This is because the z-transform cannot be directly applied to the nonlinear difference equations

Thin film was formed by the method of thermal evaporation of tin.To studying the obtained thin film, we used a field emission scanning electron microscope. The resulting image is processed using the Gwyddion 2.20 program, which is used to determine the values of the contact angles of wetting with a tin of the substrate surface and the diameter of the drops. Droplet experiments were carried out to describe the wettability behavior of the textured surfaces used in this research. The clusters can take various forms, for example, a sphere or a hemisphere. We saw that the adhesion is good when the temperature is 250 C for a substrate. In addition, an important parameter at the stage of clusters is their size distribution, since it significantly affects the morphology of the film grown at the second stage

In this research, thin films of gallium oxide β-Ga₂O₃nanostructures were prepared by pulsed laser ablation in distilled water (PLAL). Then,deposited on quartz substrate by the drop-casting method at 90 oC. The Nd-YAG laser was used with a wavelength of 1064 nm and a repetition rate of 5 Hz. The effect of increasing laser fluencies on the structural and optical properties was investigated by, Transmission electron microscope (TEM), Atomic force microscopy (AFM), X-ray diffraction (XRD), scanning electron microscopy (SEM) and spectrophotometer microscopy (UV-VIS). Crystallite size for all samples increased with the increasing the fluency of laser excepting at the fluency of laser 5.57 J/cm2was 9.78 nm. The formation of nanoparticles, spindle-like, nanosheet and core-shell of β-Ga₂O₃have been observed by the images of TEM at the fluencies of laser 4.77, 5.57, 5.97, and 6.36 J/cm2, respectively. The nanocluster and nanoroads of the β-Ga₂O₃thin films can be seen by the SEM images at the all fluencies of laser 4.77, 5.97, 6.36 and 5.57 J/cm2. Theresults of XRD investigations showedthat the diffractions patern of β-Ga₂O₃transformed from the monoclinic phase with (-201), (-402),and(-603) into orthorhombic phase with(002) ,)004(, and(006) when increased the fluency of laser.The energy bandgap decreased with the increase of laser fluencies, and the absorption peak was located in the UV region

Pulsed laser ablation technique in distilled water (PLAL) was employed to prepare colloid of spindle-like β-Ga₂O₃nanostructure and then deposit on the quartz substrate by the drop-casting method to produce cactus-like β-Ga₂O₃nanostructures at 900C. The Nd-YAG Q-Switched laser is the method to formation nanostructure from a gallium metal target by using a wavelength1064 nm, the repetition rate of about 5 Hz and the fluency of laser about 5.57 J/cm2. All the investigations of the Transmission electron microscope (TEM) and Scanning electron microscopy (SEM) showed that the formation of spindle-like β-Ga₂O3and cactus-like β-Ga₂O₃nanostructures, respectively. X-ray diffraction (XRD) of the cactus-like β-Ga₂O₃nanostructures was investigated with a crystallite size of about 9.78 nm. The formation of cactus-like β-Ga₂O₃nanostructures is the result of transformation fromthe prepared spindle-like β-Ga₂O₃nanostructures with the optimum fluency of laser of about 5.57 J/cm2

Questionnaires were designed containing questions relating to 222Rn, to know the student’s awareness of the dangers of 222Rn gas. The questionnaire was distributed randomly to 30 students of the fourth stage of both sexes in the departments of the college of science. The survey shows that the 222Rn awareness of fourth-stage students for all departments of the college of science, Mustansiriyah university is scarce.

Welding process is one of the most widely applied processes in the industry. This is due to the ease of the process and it's a quantitative process. The addition of metallic powders to the welding area has not been widely emphasized as a solution to amelioration the tribology characteristic of the welding area therefore the effect of adding metallic powders (SnS nanoparticles) to the welding area on tribology properties was studied. This effect was studied at the values of coefficientof friction, coefficient of wear and wear rate by using the ring –on –disc sliding wear test equipment was used to study the tribological behavior of low carbon steel (A 106 grade B) as pure, 6010 welded and SnS-6010 welded) under changing loads with constant velocity and in one hour for each run the dry condition at ambient temperature. The results show the coefficientof friction, coefficient of wear and wear rate increased with up load

The corrosion-resistant on the inner surface of the carbon pipeline welding alloys for two sections of the corrosion-resistant welding alloys (pure welding alloy) andwelding alloys added Tin Disulfide Nanoparticles(SnS NPs) were welded by tungsten inert gas welding (TIG). The electrochemical behavior of the weld alloy was investigated at room temperature in 3.5% NaCl solution using potentiodynamic polarization. To reveal the corrosion resistance of alloys welded joints, some significant characterization parameters such as Ecorr, Icorrand in polarization curves were analyzed and compared. The surface morphology of corrosion products was also analyzed by Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) for two cases. The results show that the corrosion resistance for welding alloys added SnS Nps appeared high corrosion resistance, lower corrosion rate, and higher protection efficiency by 48% compared with pure welding alloy.

In this study, Natural radioactivity Levels of water from samples of 10 well and at different depths 7, 3, and 12 metersmeasured with a gamma-ray spectroscopy device using High-Purity Germanium HPGedetector. The sampleswere collected from different areas of Sadr City, east of Baghdad Governorate. Al-Sadr city is Considered as one of the important areas in the capital, Baghdad, due to its population density, which constitutes about 45% of the province’s population. It is very important to assess the radiation risks in these samples because the population still depends on this water in their daily life. The concentration of naturally occurring radionuclides was determined U-238, Th-232, K-40 as all sample’s concentration is higher than the permissible limits according to UNSCEAR 2000. Measurements included the values of natural radioactivity were calculated as the Radium Equivalent Activity Raeq 0.22, External Hazard Index Hex 0.000595, Internal Hazard Index H_in 0.00119, Representative Level were collected The index Iγ 0.001467 and the alpha index I_α 0.0011, the exposure rate Raexp μR/h 0.418, and also calculated the air absorbed dose Dγin nGy/h 0.10164, Dγout nGy/h 0.2024, Dγtotal nGy/h 0.30404, AGED 0.6798, AEDEin 0.000124, AEDE_out 0.000993 and AEDEtotal 0.001117, lifetime cancer risk ELCRout 0.000436, ELCRin 0.003475 and ELCRtotal 0.003911.

The importance of investigating ultra-high energy cosmic ray particles interactions was investigated in this work. Different hadronic interaction models such as (SIBYLL, EPOS, and QGSJET) were usedair showers simulation AIRES program (version 19.04.00). In addition, the shower size of Extensive Air Showers (EAS) was calculated by estimating the longitudinal development. Moreover, the longitudinal development simulation of the two primary particles (iron nuclei and proton) was performed, taking into account theirprimary energies effect as well the zenith angle for charged particles that produced in the EAS, with energies (1017and 1019) eV. At such extremely high energies (1017and 1019) eV, new parameters as a function of the primary energy were obtained by fitting the longitudinal development curves of EAS using Lorentz function. Comparison of the results showed a good agreement between the values obtained from the parameterized longitudinal development using the Lorentz function with experimental results by Pierre Auger EAS observatory as well the simulated results by Sciutto for the primaries iron nuclei as well proton, with the electrons and the charged muons secondary particles of high energies

Hard disk drive (HDD) and storage media have the potential to revolutionize future information technology. Heat-assisted magnetic recording (HAMR) is a promising method for increasing hard disk storage density and it is one of the applications of this study. The essential component of nanoscale spintronic devices is spin current. The simulation of a thermal gradient to generate a pure spin current using an ultrafast femtosecond (fs) laser in a multilayer thin film is presented. The trilayer sample (ferromagnetic/spacer/magnetic insulator) is the candidate toachieve the spin current. Ultrafast laser with fs pulse width simulated to creates a spin diffusion spark. These pulses penetrate within the trilayer reaching the magnetic insulator due to the penetration depth that record the effect. COMSOL Multiphysics software® is used to simulate the thermal behavior within the trilayer with three-dimensional (3-D) view. The thickness of the ferromagnetic layer (Ni81Fe19) has been shown to generate a high-temperature gradient within the magnetic insulator and thereforea larger spin current.KEYWORDS: Spintronics; Spin current; Ultrafast laser; HAMR; Ferromagnetic materials; Spin current generation; COMSOL Multiphysicsالخلاصةالقرص الصلب ووسائط التخزين لديها القدرة على إحداث ثورة في تكنولوجيا المعلومات في المستقبل. يعد التسجيل المغناطيسي بمساعدة الحرارة (HAMR) طريقة واعدة لزيادة سعة التخزين على القرص الصلب وهو أحد تطبيقات هذه الدراسة. المكون الأساسي لأجهزة spintronicالنانوية هو تيار برم الإلكترون. يتم عرض محاكاة التدرج الحراري لتوليد تيار دوران نقي باستخدام ليزر فيمتو ثانية فائق السرعة في فيلم رقيق متعدد الطبقات. العينة ثلاثية الطبقات (مادة فيرومغناطيسية/ فاصل/عازل مغناطيسي) سوف تستخدم للحصول على تيار برم الإلكترون. ليزر فائق السرعة بعرض نبضة فيمتو ثانية يتم محاكاته لبدء الحصول على انتشار برم الإلكترون. تخترق هذه النبضات إلى داخل الطبقة الثلاثية لتصل إلى العازل المغناطيسي بسبب عمق الاختراق الذي يسجل برم الإلكترون. تم استخدام برنامج COMSOL Multiphysics®لمحاكاة السلوك الحراري داخل الطبقة الثلاثية مع عرض ثلاثي الأبعاد. لقد ثبت أن سمك الطبقة الفيرومغناطيسية (19Fe81Ni)ضروري لتوليد تدرج حراري عالي داخل العازل المغناطيسي وبالتالي تيار دوران أكبرINTRODUCTIONPure spin currents are made up of a flow of spins with no net charge present. There are no losses associated with electrical resistance when such pure spin currents are created with no associated charge currents, making it possible to develop a new generation of low power and environmentally friendly devices utilizing the spin of the electron, known as Spintronics [1-3]. Spin currents are important in spintronics, much as charge currents are in electronics. The spin current carries an angular momentum that can be passed to a ferromagnetic (FM) layer, causing magnetization oscillations or even entirely flipping it. This phenomenon is called spin transfer torque (STT) [4, 5]. In the last few years, several authors have reported thegeneration and measurement of spin current using the spin Hall effect [SHE] [6-9]as well as a thermal gradient using the spin Seebeck effect [SSE] [10-12]. Because of its potential for increased storage area density, heat-assisted magnetic recording (HAMR) has been suggested for the next generation of hard disk drive [13]. Shingled magnetic recording (SMR) [14], bit-patterned media (BPM) [15]and microwave-assisted magnetic recording (MAMR) [16]are other techniques that increase the density of hard disk storage. In HAMR systems, the laser is considered as a means to momentarily heat the medium, which makes it sensitive and more susceptible to magnetic effects and enables writing

This work describes a comparative study on zinc oxide/nickel oxide (ZnO/NiO) nanostructures deposited on glass substrates by chemical bath and modified bath, (CBD), and (M-CBD) techniques. The photoactivityof ZnO/NiO nanostructure films was tested on Rhodamine B (RB) dye under sunlight. The nanostructure films were evaluated using various characterization tools. Accordingly, the field-emission scanning electron microscopic (FE-SEM) images confirm that the film synthesized by CBD was flower-like nanosheetwith a thickness of 37.96 -51.36 nm. In contrast, the M-CBD film showed spherical nanoparticles with a diameter of 35.73 -49.12 nm and nanosheetof a thickness of 42.43 nm. However, both films were then subject to sunlight for 150 min. The photocatalytic efficiencies of the CBD and M-CBD films were calculated to be 76 % and 92 %, respectively. It is thus concluded that enhancing the photocatalytic degradation for the removal of RB is demonstrated by modifying the classical CBD technique.