Ab-initio study of the bandgap engineering of Al(1-x)Ga(x)N for optoelectronic applications

A theoretical study of Al(1-x)Ga(x)N, based on full-potential linearized augmented plane wave method, is used to investigate the variations in the bandgap, optical properties and non-linear behavior of the compound with the variation of Ga concentration. It is found that the bandgap decreases with the increase of Ga in Al(1-x)Ga(x)N. A maximum value of 5.5 eV is determined for the bandgap of pure AlN which reaches to minimum value of 3.0 eV when Al is completely replaced by Ga. The static index of refraction and dielectric constant decreases with the increase in bandgap of the material, assigning a high index of refraction to pure GaN when compared to pure AlN. The refractive index drops below 1 for photon energies larger than 14 eV results group velocity of the incident radiation higher than the vacuum velocity of light. This astonishing result shows that at higher energies the optical properties of the material shifts from linear to non-linear. Furthermore, frequency dependent reflectivity and absorption coefficients show that peak value of the absorption coefficient and reflectivity shifts towards lower energy in the UV spectrum with the increase in Ga concentration. This comprehensive theoretical study of the optoelectronic properties of the alloys is presented for the first time which predicts that the material can be effectively used in the optical devices working in the visible and UV spectrum.Comment: 18 pages, 7 figure

Implementation of Parallel Synchronization Method of Generators for Power & Cost Saving in University of Gujrat

In the current economic and political scenario of Pakistan where new projects of Electrical generation seems impossible, one should adopt such means so as to minimize the power consumption via load management. In this paper a relatively better Electrical power system is proposed for University of Gujrat (UOG) power system. UOG runs its all generators whether it is full load or merely a load of 20 percent as a standby power. It is suggested that if generators system is synchronized and connected in parallel, it can not only minimize the cost, number of personnel required but also increase the reliability of the system. ETAP software is used for simulation and results show that by adopting this method generation cost can be reduced up to 30 percent which is indeed a huge figure. Losses and cable parameters were calculated using this software and found this proposal quite feasible

Hepatoprotective Effect of Rheum emodi Roots (Revand chini) and Akseer-e-Jigar Against Paracetamol-induced Hepatotoxicity in Rats

Hepatoprotective effects of Rheum emodi roots and their aqueous and methanolic extracts were studied against liver damage induced by paracetamol in albino rats. In addition, the effects of herbal preparation, Akseer-e- Jigar and a control drug, silymarin were also studied. Pretreatment and post-treatment hepatoprotective effects of all these drugs were determined. The prevention of liver damage and curative effects of the drugs were judged by changes in serum ALT, AST, ALP, albumin and bilirubin (total and direct) levels. Powdered Rheum emodi roots (1 and 1.5 g/kg) and their aqueous extract did not significantly affect serum enzymes, albumin and bilirubin levels. However, treatment with powder (2 g/kg), methanolic extract (0.6 g/kg), Akseer-e-Jigar (1 g/kg) and silymarin (50 mg/kg) in both pre and post-treatment studies significantly prevented the paracetamol-induced rise of serum enzymes and bilirubin levels whereas serum albumin was raised after treatment with these drugs. It is conceivable, therefore, that Rheum emodi roots and Akseer-e-Jigar possess hepatoprotective principles that can prevent and/or treat liver damage due to paracetamol. The study has supported empirical use of the plant and its compound preparation used in traditional medicine

Peranan Metode Pictorial Riddle Terhadap Penguasaan Konsep Fisika Pada Siswa SMAN 1 Bontonompo

Penelitian ini merupakan penelitian pra eksperimen dengan one-group-pretest-posttest-design yang bertujuan untuk mengetahui seberapa besar penguasaan konsep Fisika sebelum dan setelah diajar menggunakan metode Pictorial riddle, serta peningkatan penguasaan konsep Fisika sebelum dan setelah diajar menggunakan metode Pictorial Riddle. Subjek dalam penelitian ini adalah kelas XI. IPA.5. Teknik pengumpulan data yang digunakan adalah tes penguasaan konsep fisika peserta didik yang terdiri dari 20 item dalam bentuk pilihan ganda yang telah divalidasi oleh dua orang validator. Data yang terkumpul dianalisis dengan menggunakan teknik analisis deskriptif dan inferensial (Uji N-Gain). Dari hasil analisis deskriptif penguasaan konsep siswa sebelum diajar dengan menggunakan metode Pictorial Riddle diperoleh skor tertinggi 12, skor terendah 6, skor rata-rata 8,86 dan standar deviasi 7,77. Adapun hasil analisis setelah diajar dengan menggunakan metode Pictorial Riddle diperoleh skor tertinggi 18, skor terendah 7, skor rata-rata 13,36 dan standar deviasi 10,23. Dari Uji N-Gain diperoleh N-Gain = 0,48 yang berarti penguasaan konsep fisika siswa mengalami peningkatan dalam kategori sedang.Kata Kunci: Penguasaan konsep, Metode Pictorial RiddleThis research is pre experiment with one-group-pretest-posttest-design that aims to determine how the mastery of physics concepts before and after being tauht using methods pictorial riddle and as well as improving mastery of the concepts of physics before and after being taught using methods pictorial riddle. Subjects in this study is the class XI IPA.5. the date collections technique used is the mastery test the concepts of physics students consisting of 20 items in the form of multiple choice questions that have been validated by 2 validator. Date were analyzed using descriptive analysis techniques and inferential (test N-Gain). descriptive analysis of the results of the mastery of the concepts of physics before taught using methods pictorial riddle earned the highest score of 12, the lowest score of 6, the average score of 8,86 and the standard deviation of 7,77. The results of the analysis after being taught bu using methods pictorial riddle earned the test riddle earned the highest score of 18, the lowest score of 7, the average score of 13,36 and the standard deviation of 10,23. Of N-Gain test retrieved N-Gain of 0,48 which means mastery of the concepts of physica students has increased in the medium category tes

Detection & Distinction of Colors using Color Sorting Robotic Arm in a Pick & Place Mechanism

Color sorting Robot is one of the useful, costless and fastest systems in Industrial applications to reduce manual working time and provides less human mistake when manual system is undertaken. The objective of this project is to design an efficient, microcontroller based system that pick up right color of objects and put it down at right place to optimize the productivity, minimizing the cost of the products and decreasing human mistakes. The controller used is a PIC Microcontroller (18F452) having high speed performance, low cost and 32 K bytes program memory. It communicates with color sensor TCS 3200 and various motor modules in real time to detect the right color object and to control the arm movement. Designed system can pick objects of 1kG weight and arm can rotate up to 3600 . Also, the use of easily available components reduces the manufacturing and maintenance costs. The design is quite flexible as the software can be changed according to specific requirements of the user. This makes the proposed system to be an economical, portable and a low maintenance solution for industrial applications

Stem cells differentiation and probing their therapeutic applications in hematological disorders: a critical review

Numerous lines of evidence support that bone marrow is a rich source of stem cells that can be used for research purposes and to treat some complex blood diseases and cancers. Stem cells are a potential source for regenerative medicine and tissue replacement after injury or disease, and mother cells that possess the capacity to become any type of cell in the body. They are cells without specific structure and characterized by their ability to self-renew or multiply while maintaining the potential to develop into other types of cells. Stem cells can normally become cells of the blood, heart, bones, skin, muscles or brain. Although, there are different sources of stem cells, all types of stem cells have the same capacity to develop into multiple types of cells. Stem cells are generally described as unspecialized cells with unlimited proliferation capacity that can divide (through mitosis) to produce more stem cells. Several types of adult stem cells have been characterized and can be cultured in vitro, including neural stem cells, hematopoietic stem cells, mesenchymal stem cells, cardiac stem cells and epithelial stem cells. They are valuable as research tools and might, in the future, be used to treat a wide range of diseases such as hematological hereditary diseases, Parkinson's disease, diabetes mellitus, heart disease and many other diseases. Currently, two types of stem cells have been identified based on their origins, namely embryonic stem cells and adult stem cells. Collectively, although many kinds of literature have been studying stem cell application in terms of clinical practice, stem cell-based therapy is still in its infancy stage

Evaluation of an intervention program to promote neck care for computer user among staff and students of a Malaysian public university

Background: Computers are one of the most useful equipment developed in this electronic era. However incorrect posture and prolonged use of computers are risk factors for developing neck pain. A health promotion program was developed to educate computer users regarding neck care. The program was then evaluated to observe its effects in increasing knowledge, attitude and practice among the respondents. Materials and Methods: This was an intervention study conducted in a local public university. A set of materials consisting of a pamphlet, posters and questionnaire, were developed for the study. The pamphlet and posters were based on a study on exercises performed while sitting, while the questionnaire was based on a study assessing a neck care intervention program. The materials were assessed and validated prior to the program. Study variables were respondents’ characteristics, knowledge, attitude and practice/intention to practice neck care. The knowledge, attitude and practice/intention to practice were measured at baseline and post intervention and the changes were compared. Result: A total of 41 respondents participated. At baseline, only 61% of the respondents knew that daily computer use for 2 hours or more increased the risk of developing neck problem, however the percentage increased significantly after the program (P=0.001). The attitude toward the necessity to do exercise while working in front of the computer was 85.5% at the beginning but had also increased significantly after the program (P=0.008). All parameters forming the intention to practice good neck care (i.e. to sit with straight upper back, to do simple neck exercise while working in front of the computer and to adjust sitting position to maintain good posture) were significantly increased (P<0.05) after the intervention program. Conclusion: The knowledge and attitude regarding good neck care and the intention to practice good neck care significantly improved after the intervention program. More intervention programs to promote neck care for computer users should be carried out

Kesadaran Lingkungan di Kalangan Santri terhadap Pembangunan Berkelanjutan

This study aims to identify the level of awareness of the concept of sustainable development among middle high school students at three Islamic boarding schools (pesantren). The survey was conducted with 514 respondents (level XI) from Pesantren Daar El Qolam (Tangerang), Pesantren Al Musaddadiyah (Garut) dan Pesantren Buntet (Cirebon). Dependent variables were the level of environmental awareness of the concept of sustainable development and practices: i.e. Sustainability practices awareness and behavioral and attitudinal awareness, environmental education and Islamic environmentalism. Independent variables were the three types of pesantrens above. The research instrument used was the questionnaire, using a Likert scale. The method of analyzing data was descriptive, Spearman Correlation and one-way Anova, using SPSS software ver. 11.0. Research outcomes showed that all the students from the three pesantren institutions indicated that they have a moderate level of sustainable development awareness (mean=3.86; sd=0.86). They also believe Islam teaches about environment -- Islamic environmentalism –giving guidance on good practice toward the environment (90.38%). Unfortunately their environmental theory gained from schools was not related to their daily attitude, which in turn related to their behavioral awareness (ρ=0.024). They rarely practice in the level of sustainability practice awareness (52%), and behavioral attitude and awareness (62%). But emotionally they have a high concern to the environmental problems (89%). The One-Way Anova showed there were differences between the three institutions in teaching about the environment, Islamic environmentalism and behavioral attitude awareness, but there were no differences between sustainability practice awareness and emotional awareness

Dual-wavelength generation with terahertz spacing using GaAs–AlGaAs microring resonator waveguides

In this research, we present the demonstration of GaAs–AlGaAs waveguide resonators. Two microring resonators (MRRs) have the same radius of 6.36 μm are coupled and used to generate dual-wavelength with terahertz (THz) spacing. We have shown that such resonators can be used to generate ultra-wide free spectral range (FSR) pulses with THz spacing, providing THz photonics communication signals. A Gaussian laser beam with power of 1 W is used as input. The MRRs are modeled by using GaAs–AlGaAs with GaAs core having refractive index of 3.368 surrounded by AlGaAs (n = 3.135). The drop port outputs of the MRRs system contains a dual-wavelength generated within 33 nm wavelength range, having a linewidth of 1.48 (185.320 GHz) and FSR of 3.95 nm (500 GHz) which varies slightly along the wavelength. Results were generated using the time-domain travelling wave (TDTW) method and capable of modeling both active and passive photonic circuits