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Abstract Greenhouse gases are major contributors to global warming, and their concentration is increasing due to the widespread use of fossil fuels. Coal bed methane (CBM) offers a potential solution to this issue. However, the gas adsorption mechanisms of CBM, particularly in the context of coal-derived asphaltenes, are not fully understood. This study provides a comprehensive theoretical investigation of the competitive adsorption of carbon dioxide (CO $$_2$$ 2 ), methane (CH $$_4$$ 4 ), and nitrogen (N $$_2$$ 2 ) in the processes of CO $$_2$$ 2 - and N $$_2$$ 2 -enhanced coalbed methane recovery, with a focus on coal-derived asphaltenes functionalized with CH $$_4$$ 4 , NH, O, and S groups. Using the Grand Canonical Monte Carlo (GCMC) simulation method and performing Molecular Dynamics (MD) simulations, we studied the adsorption process. To investigate the electronic effects and nature of the interactions, we performed density functional theory (DFT) calculations. The adsorption energy values and non-covalent interactions (NCI) for the adsorption of gases signify the physical adsorption (van der Waals interaction), with CO $$_2$$ 2 exhibiting the highest (absolute) adsorption energy. The Monte Carlo results indicated that elevated temperatures led to a reduction in adsorption capacity. Coal-derived asphaltenes demonstrated greater selectivity for CO $$_2$$ 2 compared to CH $$_4$$ 4 and N $$_2$$ 2 in competitive adsorption, especially at elevated temperatures. Our findings highlight the significant potential of our asphaltene model, not only in mitigating CO $$_2$$ 2 greenhouse gas emissions but also in recovering CH $$_4$$ 4 , which is a valuable resource.

Abstract Matter-antimatter plasmas, such as electron-positron pair plasmas, are frequently observed in various astrophysical phenomena. In laboratory settings, electron-positron pairs have often been generated using high-Z converters irradiated by either direct laser pulses or laser-driven electron beams. Here we generate charge-neutral electron-positron beams with energies in the GeV range, utilizing bremsstrahlung gamma rays. Specifically, intense high-energy gamma rays produced electron-positron pair particles in a lead converter via the Bethe-Heitler process. The produced pair beams exhibited neutrality across all converter thicknesses throughout the energy spectrum spanning from 10 MeV to 1.8 GeV. Pairs with energies surpassing 1 GeV constituted up to 26% of the total kinetic energy within the spectrum. The experimental results were in good agreement with our Geant4 Monte Carlo simulations. These GeV-scale neutral pair particle beams have potential applications for understanding energetic astrophysical phenomena and high-energy particle physics.

We investigate the generation of terahertz (THz) radiation from laser-wakefield acceleration (LWFA) in a helium gas jet. We consider a three-dimensional setup incorporating a realistic gas density distribution and use particle-in-cell simulations to study the interaction of a femtosecond intense laser pulse with the gas medium. Our results show that LWFA can efficiently produce THz radiation. In the simulations, we use multiple probes to record the electric and magnetic fields arising from the interaction. In addition, we compare the results of fixed and moving window simulation boxes used to capture electromagnetic fields in the THz range. We demonstrate that a moving window with a 600 μm width can be significantly useful for THz studies. We further analyze the spectrum of spatially and temporally resolved electromagnetic radiation and its emission angle. Our results are consistent with experimental data. Our findings provide valuable insights into the potential of LWFA as a strong source of THz radiation.

The electrons, accelerated by the laser ponderomotive force and subsequent plasma wakefields, radiate broadband emission continuously along the laser propagation direction, resulting in multi-mJ THz radiation in the far field.

The progressive application of non-linear loads in distribution systems (DS) increases current harmonics flow in DS's apparatuses, especially distribution transformers (DTs). Since DTs' operating temperature rises due to the harmonics flow, their loading should be reduced such that the hot spot temperature (HST) is preserved under its permissible value. This means that DTs' available capacity is influenced by load harmonic content. In this paper, a novel formulation for DTs' failure rate in the presence of harmonics is presented as a function of load harmonic contents. Using the suggested equivalent failure rate, DTs' available capacity in harmonic polluted DS is mathematically formulated. Additionally, the presence of the harmonic increases the HST, leading to DTs' aging acceleration. Therefore, the impact of harmonic components on DTs' aging is arithmetically modeled. To evaluate the efficacy of the suggested reliability model, it is applied to three distinct DTs having respectively industrial, commercial, and residential loads. The obtained results indicate that the available capacity of DTs with the same rated capacity would be different regarding to their load harmonic contents. On the other hand, it is comprehended from the achieved results that the aging acceleration factor (Faa) of the DTs increases owing to their load harmonic contents.

Abstract Purpose: To determine the diagnostic accuracy of Pentacam Cataract Grading Scale (PCGS) versus the Lens Opacities Classification System (LOCS III) in scaling pure age-related cataract. Methods: Between April 2016 and May 2017, eyes of 281 patients were evaluated for grading of lens opacity. We used LOCS III and PCGS. Patients with pure age-related cataract with no previous history of eye surgery, eye trauma, or chronic systemic disease between 50 and 95 years of age were included. The examination of the patients was done, using slit lamp and LOCS III grading chart. The second examination was done a week later, using Oculus Pentacam. Next, we graded them using a PNS grading score. Spearman's rank correlation and a Bland-Altman Plot were implemented for analysis using MedCalc 14. 8.1. P < O.05 was considered as statistically significant. Results: Three hundred eyes were examined. Of them, 189 patients were male, and patients between 70 to 80 years old were the most common group. The correlation between grades of two methods was 0.47 (P < 0.001). Results of the Bland-Altman plot showed a moderate alignment between the two methods. Conclusion: The association between LOCSIII and PCGS is not so favorable, however, it is an economical and effective method to assess lens opacities is LOCSIII. PCGS can be used in early diagnosis. For a definitive diagnosis and appropriate therapeutic intervention, an ophthalmological examination is needed.

The fast growth of technology along with the expansion of industries has exacerbated environmental pollution. The diversity and broad application of various chemicals in the textile and agriculture industries, and eventually, the release of wastewater of such activities into the environment is a severe threat for aquatic ecosystems. Advanced oxidation methods based on the production of active species, such as hydroxyl radicals, nonselectively destroy a wide range of contaminants. Among the advanced oxidation methods, heterogeneous photocatalysts using semiconductors attracted a great deal of interest. In this project, Pd doped WO3 nanoribbons on a graphene substrate were prepared via the hydrothermal method and were used as photocatalysts to degrade a textile dye (Acid Blue 92). The effect of Pd and graphene incorporation on the surface properties, morphology, and photocatalytic activity of WO3 nanoribbons was investigated using XRD, BET, SEM, FTIR, DRS, and XPS techniques. The BET results demonstrated that the synthesis of WO3 nanoribbons on graphene oxide substrate and the reduction of obtained photocatalyst in the H2 atmosphere increased the surface area of the photocatalyst up to twice its normal size. In the next step, the ability of the photocatalyst to degrade blue-acid 92 textile dye in the presence of visible light was investigated and the degradation rate was calculated. The results confirmed that the reduced nanocomposite in the presence of H2 atmosphere in comparison with other samples has the highest dye degradation rate of 9×10-3min-1 with an efficiency of 60%. This nanocomposite, with its high surface area, facilitates the adsorption of dye-molecules on the active sites of the surface, thus greatly increasing the rate of degradation of the contaminant adsorbed on the photocatalyst surface. Eventually, different kinetic models were applied to investigate the reaction kinetics, and in each case, the correlation coefficient was calculated. The results of correlating the experimental data with the kinetics equations depicted that the dye degradation kinetics according to the Langmuir-Hinschlod model has a quasi-first-order mechanism.

Abstract Due to wind and uneven distribution of the field along the insulator, a kind of non‐uniform contamination is deposited on the insulator surface as fan‐shaped and longitudinal pollution. This paper investigates such non‐uniform pollution from theoretical and experimental points of view. For this aim, the residual resistance of the pollution layer is formulated based on the geometry of fan‐shaped and longitudinal non‐uniform pollution. Also, the arc current is formulated using the arc Obenaus's equivalent circuit for a constant arc voltage in terms of arc length propagation. Finally, the AC dynamic theoretical model of pollution flashover is proposed that can estimate flashover parameters for different values of the fan‐shaped density degree (J), extension degree (K) and longitudinal non‐uniform pollution density degree (Z) considering instantaneous variables in arc progression. It results that with increasing Z, the flashover voltage increases, while by increasing the J and K, the flashover voltage decreases. To validate this model, the experimental tests are performed on the sample silicone rubber (SiR) insulator that show acceptable accuracy of theoretical model. Furthermore, based on experimental results, a new correction coefficient is proposed under fan‐shaped and longitudinal pollution that varies in the range of 0.85–1.62.

Salinity is a major environmental stress, reducing growth and yield of a wide variety of crops all over the world. The present study assessed effects of humic acid and salinity stress on the growth and some physiological responses of wheat in a pot experiment. The layout was 4×4 factorial experiment in RCBD design with salinity stress levels and humic acid concentrations as main factors in Ilam University during 2016. Treatments were the combination of four levels of salinity stress including stress-free conditions (irrigation by distilled water), and 4, 8, and 12 dS/m NaCl and four concentrations of humic acid including 0 (as a control), 50, 100, and 150 mg/l. The statistical analysis showed that salinity stress and humic acid application had significance effects on the morphological, physiological, and biochemical parameters of the wheat plants. Salinity stress imposed negative effects on plant growth and productivity. Under salinity conditions, growth parameters and yield attribute, relative water content, and chlorophyll reduced, but electrolyte leakage and antioxidant enzyme activity increased. Application of humic acid significantly increased plant growth parameters, chlorophyll content, and antioxidant enzyme activity, and decreased electrolyte leakage content. The highest salinity tolerance was obtained with 150 mg/l humic acid application. In general, results showed that the application of humic acid through affecting physiological parameters decreased adverse effects of salinity stress on the wheat plants.

Pollution is known as one of the important and effective factors on the performance of polymeric insulators. In practice, the deposit contamination on the insulator surface is not uniform completely and is non-uniform contamination. So far, comprehensive research has not been carried out on the effects of different forms of non-uniform contamination on the performance of the insulators. In this paper, the effect of uniform contamination, longitudinal non-uniform pollution and fan-shaped non-uniform pollution in three levels of light, medium and heavy contamination on the potential and electrical field distribution of a 20 kV polymeric insulator using Comsol Multiphysics software have been done and the results have been Analyzed. In longitudinal non-uniform pollution, the severity of pollution in the near of high voltage and ground electrodes regions is heavier than the middle region, and in fan-shaped non-uniform pollution, the severity of pollution in the leeward side region is heavier than the windward side region. The results show that in slightly uniform pollution, the electric field decreases and its amplitude increases with increasing the pollution intensity. In longitudinal non-uniform pollution, electrical potential is almost constant in the near of electrodes and the electric field intensity has been decreased. Also, in the fan-shaped non-uniform pollution, the electric field intensity has been increased in the leeward side region.

 This paper presents the calculation of maximum lightning overvoltage for a transmission system consisting of overhead lines in combination with an underground power cable. For this purpose, a 132 kV overhead transmission line combined with an underground cable is considered. This combined line has been protected by surge arresters. EMTP-RV and MATLAB software are used to conduct the modeling, simulation and calculation works. Lightning strikes on the tower top and results in large over-voltages appearing along overhead lines and cable. Underground cable characteristics have significant effects on maximum lightning over-voltages. Therefore, the three characteristics considered for these effects are: (i) cable length; (ii) cable core resistivity, (iii) cable sheath resistivity. Tower footing resistance effect is also included in the computer simulation. ABSTRAK: Kajian ini berkenaan tentang pengiraan takat maksimum voltan kilat berlebihan bagi sistem transmisi melibatkan kabel atas kepala termasuk kabel tenaga bawah tanah. Bagi tujuan ini, talian kabel penghantaran atas kepala 132 kV termasuk kabel bawah tanah telah diambil kira. Kombinasi kabel ini dilindungi dengan penahan lonjakan voltan tenaga. Perisian EMTP-RV dan MATLAB telah digunakan untuk membuat model, simulasi dan kerja-kerja pengiraan. Panahan petir di atas puncak bangunan merupakan penyebab utama voltan berlebihan muncul bersama talian atas kepala dan kabel. Ciri-ciri kabel bawah tanah merupakan faktor penyumbang utama ke atas voltan berlebihan daripada kilat. Oleh itu, tiga kes telah diambil kira sebagai penyumbang voltan berlebihan: (i) panjang kabel; (ii) rintangan teras kabel, (iii) rintangan sarung kabel. Kesan rintangan tapak bangunan turut diambil kira dalam simulasi komputer.

Objectives This study analyzes the consumption pattern of health care costs in Iranian urban households’ life cycle costs with a focus on aging period during 1997 to 2013. Methods & Materials This study is a secondary analysis conducted using data from the UN Population Division and household income and spending, with the help of pseudo-panel method. In order to recreate and analyze data, STATA software is used. In addition, the index of scale is used for adjusting the amount of costs relative to household size and age of people in the household, and the consumer price index is used in order to adjust inflation of the costs in different years. Results Findings showed that the population is transitioning from youth to old age; the number of elderly is estimated to reach over 10 million people, i.e. more than 11%, in 2036. Analysis of the effects of aging on health care costs show that demand for consumption from age 25 to 50 years is gradually growing; this demand then reaches its climax in the final years of an individual’s life. The effect of generation showed that new generations have a higher demand for consumption of healthcare costs compared to the previous generations. The results of the study indicate that the demand for consumption is initially fixed and then is increased or decreased in the mentioned years. Conclusion Based on the results of this research, it can be said that people throughout their life cycle always allocate a percentage of their total spending to health care costs, but the percentage of this allocation is different at different ages. In a way the demand for healthcare costs increases with aging, it rises significantly in the old age. At the macro level, due to an increase in the percentage of elderly in the population over the next decade, there will also be an increase in the share of health care costs.

Laser wakefield electron acceleration (LWFA) is an emerging technology for the next generation of electron accelerators. As intense laser technology has rapidly developed, LWFA has overcome its limitations and has proven its possibilities to facilitate compact high-energy electron beams. Since high-power lasers reach peak power beyond petawatts (PW), LWFA has a new chance to explore the multi-GeV energy regime. In this article, we review the recent development of multi-GeV electron acceleration with PW lasers and discuss the limitations and perspectives of the LWFA with high-power lasers.

Flashover of polluted insulators in contaminated areas is one of the most important factors influencing the operation of transmission and distribution lines and finally line outages. Therefore, it is essential to prevent and detect flashover in the insulators. Hence, utilizing the insulator status monitoring systems and predicting their functions have absorbed a lot of attention over the recent years. In this paper, a new method is proposed for flashover prediction in porcelain and glass insulators. In this regard, a variety of experiments has been conducted on different types of insulators under different environmental conditions and analysis of their leakage current harmonics have been investigated. Fast Fourier Transform (FFT) analysis applied to the saved leakage current waveforms shows a strong correlation between the ratio of the third to fifth harmonic amplitudes by regarding the occurrence of critical conditions and degree of insulator ageing. Then, the third to fifth harmonic ratio of the leakage current (R3/5) has been proposed as an indicator of critical conditions in porcelain and glass insulators. The results of these experiments show that the mentioned harmonic ratio has a definite and constant procedure against the changes in the type of pollution and humidity rate. The results of experiments have indicated that increasing the index R3/5 to more than one represents a critical condition in the insulators and estimates a high probability of flashover. Also in whole the tests, value of the total harmonic distortion (THD) and flashover voltage are measured.

The aim of this study was the survey of entrepreneurial personality traits of engineering students of Isfahan University. The statistic population consisted of students in the fields of engineering (Civil, Electrical, Mechanical, Chemical, Computer) and with random method sample of 200 were selected from the target population. The research method was descriptive and instrument for data collection was a questionnaire of Iranian entrepreneurs ' personality traits. For data analysis, descriptive statistics (frequencies and percentages) were used. The results showed that in the overall scale entrepreneurship more than 50 percent of students were in poor or very poor level, In the subscales, the subscales of internal locus of control, actionism , tolerance of ambiguity , and dreaming of more than 50 percent of the subjects were strong or very strong level. But on the other subscales over 50 percent of the subjects were in poor or very poor level.

Background: The 131I radioisotope is used for diagnosis and treatment of hyperthyroidism and thyroid cancer. In optimized Iodine therapy, a specific dose must be reached to the thyroid gland with minimum radiation to the cervical spine, cervical vertebrae, neck tissue, subcutaneous fat and skin. Dose measurement inside the alive organ is difficult therefore the aim of this research was dose calculation in the organs by MCNPX code. Materials and Methods: First of all, the input file for MCNPX code has been prepared to calculate F6 and F8 tallies for ellipsoidal thyroid lobes with long axes is tow times of short axes which the 131I is distributed uniformly inside the lobes. Then the code has been run for F6 and F8 tallies for variation of lobe volume from 1 to 25 milliliters. From the output file of tally F6, the gamma absorbed dose in ellipsoidal thyroid, spinal neck, neck bone, neck tissue, subcutaneous fat layer and skin for the volume lobe variation from 1 ml to 25 ml have been derived and the graphs are drew. As well as, form the output of F8 tally the absorbed energy of beta in thyroid and soft tissue of neck is obtained and listed in the table and then absorbed dose of bate has been calculated. Results: The results of this research show that for constant activity in thyroid, the absorbed dose of gamma decreases about 88.3% in thyroid, 6.9% at soft tissue, 19.3% in adipose layer and 17.4% in skin, but it increases 32.1% in spinal of neck and 32.3% in neck bone when the lobe volume varied from 1 to 25 milliliters. For the same situation, the beta absorbed dose decreases 95.9% in thyroid and 64.2% in soft tissue. Conclusion: For the constant activity in thyroid by increasing the thyroid volume, absorbed dose of gamma in thyroid and soft tissue of neck, adipose layer under the skin and skin of neck decreased, but it increased at spinal of neck and neck bone. Also, by increasing of the lobe volume in constant activity, the beta absorbed dose reduced. Therefore, whatever the thyroid lobe is small the administered value of 131I increased to induce the suitable dose.

The tax capability of each region depends not only on people’s ability to pay taxes, but also on government’s ability to receive it. The great portion of a region’s informal sector indicates government’s lack of control over the economic activities in that region. Therefore,with the great share of the informal sector, ability of the government for receiving taxes and as a result the tax potential is reduced. However, part of the informal sector businesses, if supported, can be transferred to the formal sector (upgradable informal sector) and affect the tax potential of the society positively. This paper attempts to assess the effect of the upgradable informal sector of Kohgiluye and Boyer Ahmad Province on the tax potential of the region. An assessment of the lost tax potential in each major economic sector of the province indicates that approximately half of the informal sector’s businesses of the province is upgradable and can be transferred to the formal sector.

The interaction of Jack Bean Urease with cobalt (II) ion was studied by Isothermal Titration Calorimetry (ITC) at 300 K and 310 K in 30 mM Tris buffer, pH=7. The stability of the enzyme increases due to its binding with cobalt ions. The extended solvation model was used to reproduce the heats of Co2++JBU interaction. It was found that there is a set of 12 equivalent and noninteracting binding sites for Co2+ ions. The association equilibrium constant and the molar enthalpy of binding are 4260.76M-1, -16.5 kJmol-1 at 300 K and 3438M-1, -16 kJmol-1 at 310 K, respectively.

In this paper complexation reaction between Yb3+ and Human serum albumin is examined using isothermal titration calorimetry (ITC). The extended solvation model was used to reproduce the enthalpies of HAS+Yb3+ interactions over the whole range of Yb3+ concentrations. The binding parameters recovered from this model were attributed to the structural change of HSA. The results show that Yb3+ ions bind to HSA with three equivalent affinity sites. It was found that in the high concentrations of the ytterbium ions, the HSA structure was destabilized.

Objectives: The main purpose of this study is to investigate the elderly cognition of functional limitation, activity limitation, mental disorder and social and demographic characteristics (socioeconomic status, education, working status, sex and age) and their impacts on their self-perceived health status. Also to fit the health status data with Johnson and Wolinsky's model and offering a proper theoretical model for simultaneous assessment of variables were among other objectives of this study. Methods & Materials: Via a descriptive, analytical and cross-sectional study, a survey conducted to investigate the health status of Iranian elderly in the year of 2002. Two approaches were used to explain the self-perceived health status among such elderly: the population health approach and health related indicator approach. Results: The results of statistical analysis showed that elderly who have more functional and activity limitation, their self-perceived health status were weaker than those who had less functional and activity limitation. It is also found that people from lower class who have less income and lower education, have a lower self-perceived health status in compare to those who are from higher class with higher education and more income. Conclusion: Functional limitation, activity limitation, mental disorder, socioeconomic status, education and age are significant determinants of the self perceived health status among elderly.

Purpose- In order to develop new bone imaging agent based on bisphosphonate moiety, an alendronate based complex was designed and prepared in this study. Methods- A DTPA-conjugated bis-alendronate analog (DTPA-bis-ALN) 3, was prepared for possible bone imaging after radiolabeling with 111In. Radiolabeled DTPA-bis-ALN complex was prepared starting radionuclide in chloride form and DTPA-bis-ALN in 30-90 min at 50-60°C in acetate buffer followed by solid phase purification on C18 Sep-Pak cartridge. RTLC was used for radiochemical purity determination followed by log P determination, stability studies, hydroxyl apatite tests and biodistribution studies in normal rats and imaging. Results- Specific activity 1.1-1.3 TBq/mmmol was obtained for 111In-complex. The log Ps was calculated 0.48 for the complex consistent with water soluble complexes followed by stability test. The biodistribution of the labeled compound in normalrats demonstrated activity uptake in kidneys. Conclusions- The anionic property of poly-dentate complex led to renal excretion instead of bone accumulation. These data showed that the developed complexes are not suitable agents for bone imaging as expected.

The increasing expansion of resential areas and urbanization together with industrial and agricultural development in Iran have made it possible to destroy the ecological system of the natural society remarkably. The watershed of Latian Dam , as one of the sources to supply the drinking water of Tehran is of specific geographical and climatic important ,and because it is adjutant to Tehran , it has exprienced considerable change in population and residential expansion. In this research, we have tried to focus on the changes of the quality of water in the Jajrood River , by surveying the population growth of this area, in recent years. Considering the results of this research the number of tourist have also increased remarkably in the last few years and the quality of water has also been changed because of the increasing number of tourist in the region. Therefore ,without regarding the ecological ,hygienically and controlling necessities in this area , there many be dangerous conditions and consequences forced upon one of the important drinking water sources of Tehran in the near future.

One of the challenges for laser-driven proton beams for many potential applications is their stability and reproducibility. We investigate the stability of the laser driven proton beams through statistical analysis of the data obtained by employing a high repetition rate tape driven target system. The characterization of the target system shows the positioning of the target within ∼15 μm in the focal plane of an off-axis parabola, with less than a micron variation in surface flatness. By employing this stable target system, we study the stability of the proton beams driven by ultrashort and intense laser pulses. Protons with maximum energies of ∼6±0.3 MeV were accelerated for a large number of laser shots taken at a rate of 0.2 Hz with a stability of less than 5% variations in cutoff energy. The development of high repetition rate target system may provide a platform to understand the dynamics of laser driven proton beams at the rate required for future applications.