Search

The goal of this investigation is to ascertain how peer education about bone health affects students' knowledge. A one-group pre-test-post-test design was used in the pre-experimental study design. Twenty-nine students were chosen as the sample for this study using a straightforward random sampling procedure. 27 questions about bone health were included in the questionnaire that served as the study tool. The t-test statistical test was used for univariate and bivariate data analysis. According to the findings, there was a significant difference in knowledge between the two time periods before and after the peer education intervention for bone health (p-value = 0.000). The obtained beta squared value was 0.89, which indicated that peer education interventions for bone health had a significant impact on knowledge growth. A similar study will be conducted in the future to assess attitudes and behavior, as well as the presence of a control group.

Penelitian ini bertujuan untuk menguji dan mengetahui pengaruh Women Lifestyle Dan Service Quality Terhadap Keputusan Pembelian Konsumen Miranda Coffee Shop yang Studi kasus pada Konsumen Wanita. Sampel penelitian ini adalah Sampel yang digunakan pada penelitian ini yaitu melakukan pengambilan sampel pada masyarakat di Kota Padang yang sudah pernah melakukan pembelian secara online maupun offline Sebanyak 171 Responden.Pengelolaan data penelitian dilakukan menggunakan software IBM SPSS Statistics 21.Hasil penelitian menunjukkan Women Lifestyle dan Service Quality berpengaruh positif dan signifikan terhadap Keputusan Pembelian Konsumen Miranda Coffee Shop.

This study aims to determine the effect of various kinds of organic fertilizers and watering differences in mungbean (Vigna radianta L.) plants. This research takes location in Parangtritis Village, Kertek, Bantul Regency, Daerah Istimewa Yogyakarta, in the altitude of ± 10 meters above sea level. The characteristic of soil in this location is sandy. The research used split plot design by applying two factors. The first factor in this study was watering consisting of once a day and three days once. While the second factor is the provision of organic fertilizers, namely without applying fertilizers, compost, vermicompost, guanophosphate. The variables observed were in the generative phase which included number of pods, pod weight per plant, seed weight per plant, seed weight per hectare, weight of 100 seeds, carbohydrate content, protein content, and fat content. The analysis of the observational data used variance at the 5% real, while the differences between treatments were tested by using the Duncan Multiple Range Test at the 5%. Based on the research results, it can be concluded that the treatment of compost, vermicompost and guanophosphate gave higher yields per hectare than without fertilizer. The treatment of watering frequency once a day gave a higher yield per hectare of green beans than the frequency of watering once every three days. The combination of giving compost with a frequency of watering once every three days on mungbean plants gives the highest yield quality.

Tujuan penelitian ini adalah mengkaji pengaruh pupuk kandang dan kompos terhadap kalium tersedia rizosfer tanaman kacang hijau. Penelitian dilaksanakan di Desa Parangtritis, Kretek, Bantul, dengan ketinggian ± 10 m dpl, pH tanah 5,6 – 6,0, kelembaban udara 65 – 85%. Jenis tanah adalah tanah berpasir. Percobaan menggunakan Split plot dua faktor: (1) frekuensi penyiraman sebagai main plot yang terdiri atas satu kali sehari dan tiga hari sekali, (2) pemberian pupuk kandang dan kompos sebagai sub plot. yaitu : tanpa pemberian pupuk, pupuk kandang sapi, pupuk kandang kambing, dan pupuk kompos. Variable yang diamati adalah pada fase vegeratif, meliputi rasio tajuk-akar segar, rasio tajuk-akar kering, kapasitas tukar kation, kalium tersedia tanah, dan kandungan kalium jaringan kacang hijau. Analisis data menggunakan sidik ragam jenjang nyata 5%, perbedaan antar perlakuan diuji dengan uji jarak berganda Duncan. Hasil: perlakuan pupuk kompos memberikan ketersediaan kalium tanah teringgi (53 ppm), diikuti pupuk kandang kambing (48,5 ppm), pupuk kandang sapi (26 ppm) dan tanpa pupuk (24 ppm). Perlakuan penyiraman sehari sekali memberikan ketersediaan kalium tanah 40 ppm lebih tinggi dibanding penyiraman tiga hari sekali (33,5 ppm). Perlakuan pupuk kompos, kandang sapi, dan kandang kambing memberikan kandungan kalium jaringan tanaman kacang sama dengan tanpa pupuk. Perlakuan frekuensi penyiraman tidak memengaruhi kandungan kalium jaringan tanaman kacang. Perlakuan pupuk kompos, kandang sapi dan kandang kambing memberikan Sum Growth Rate lebih tinggi dibanding tanpa pupuk. Penyiraman sehari sekali memberikan Sum Growth Rate lebih tinggi dibanding penyiraman 3 hari sekali.

This study aims to determine methods, characteristics, and patterns of preaching to the converts. The object is Ustadzah Lilis Mulyani as a da'wah (Da'i) actor who conducts da'wah activities to converts in Teratak Fitrah Kota Kinabalu Sabah Malaysia. Researchers use a theory that is in accordance with the object of research, namely the SMCR theory found by David Berlo. This SMCR theory consists of: Source, Message, Channel, and Receiver. The source is what makes the message, while the message is the idea that is explained or the code in the form of symbols to be understood. The results showed that the methods and approaches used by Ustadzah Lilis Mulyani to the converts in developing and spreading their da'wah using the methods of da'wah bil-oral, bil-hikmah, mauidzatul hasanah and mujadalah bil-lati hiya ahsan. The impact of this research is the creation of preaching patterns or models of converts and scientific development of da'wah for the converts. Keywords: Patterns of Da'wah; Ustadzah; Method; Muslim ABSTRAK Penelitian ini bertujuan mengetahui metode, karakteristik, dan pola dakwah dakwah kepada muallaf. Objek adalah Ustadzah Lilis Mulyani sebagai pelaku dakwah (Da’i) yang melakukan kegiatan dakwah kepada muallaf di Teratak Fitrah Kota Kinabalu Sabah Malaysia. Peneliti menggunakan teori yang bersesuaian dengan objek penelitian yakni teori SMCR yang ditemukan oleh David Berlo. Teori SMCR ini terdiri dari: Source, Message, Channel , dan Receiver . Sumber adalah yang membuat pesan, adapun pesan itu adalah gagasan yang diterangkan atau kode yang berupa simbol-simbol untuk di pahami. Hasil penelitian menunjukkan bahwa tata cara dan pendekatan yang digunakan oleh Ustadzah Lilis Mulyani kepada golongan muallaf dalam mengembangkan dan menyebarkan dakwahnya dengan menggunakan metode dakwah bil-lisan, bil-hikmah, mauidzatul hasanah dan mujadalah bil-lati hiya ahsan. Adapun dampak penelitian ini adalah terciptanya pola atau model dakwah terhadap muallaf dan pengembangan keilmuan dakwah bagi golongan muallaf. Kata Kunci : Pola Dakwah; Ustadzah; Metode; Muallaf

This study synthesized collagen-chitosan/PVA nanofiber composites using the electrospinning method. Characterizations included Fourier transform infrared spectroscopy (FTIR) and surface morphology using scanning electron microscopy (SEM). Investigations were carried out on tensile strength, degradation rate, and antibacterial test. It was found that the functional groups C–H, –OH, C–O, C–N, and N–H were suitable for PVA, collagen, and chitosan materials. The SEM showed that increasing the PVA composition caused a change in fiber diameter ranging from 34.64 to 71.63 nm. The tensile strength results show that the smallest nanofiber diameter has the highest ultimate strength value of 5.6 ± 0.4 MPa. In addition, it was found that the rate of degradation was directly proportional to the increase in concentration. Antibacterial activity test was carried out using two types of bacteria, namely gram-positive bacteria S. aureus and gram-negative bacteria E. coli. The results showed that the collagen-chitosan/PVA nanofiber composite had a diameter of antibacterial inhibition for E. coli and S. aureus bacteria, respectively.

These studies are aimed to investigate influences of Ga dopant and As dopant on the optical properties of silicene. Silicene, a silicon analog of graphene, is expected to be better suited than graphene for the electronics industry, which is currently still dominated by silicon. In order to expand its application, its properties must be controllable. The development of the properties can be done by doping or applying external electric fields and stress. Like carbon, silicon also belongs to group IV of the periodic table. Ga (elements from group III) and As (element from group V) can play the role of dopant donor or acceptor in silicene. Therefore, the Density Functional Theory (DFT) calculations were carried out using a general gradient approach in order to investigate the influence of Ga atoms and Al atoms on the optical properties of silicon dioxide. The optical properties studied include refraction, reflection, and absorption. The results show that Ga doping, As doping, and Ga-As codoping reduce the value of the linear optical properties. The ability to control and exploit its optical properties shed light on designing silicene-based electronic and spintronics materials.

Konversi biomassa dengan metode pirolisis membutuhkan suhu yang tinggi sekitar 200-500oC tergantung dari jenisnya. Untuk mencapai suhu tersebut dibutuhkan tekanan eksternal yang mengakibatkan proses konversi tidak efesien. Diusulkan suatu skema baru yaitu reaktor pemanas menggunakan metode perangkap suhu tanpa memberikan tekanan eksternal. Pengujian telah dilakukan dengan cara memanaskan 4liter minyak goreng pada kecepatan putaran pengaduk yang bervariasi yaitu 5 rpm, 10 rpm, 20 rpm dan 30 rpm. Hasil yang diperoleh, makin cepat putaran pengaduk, mengakibatkan kenaikan suhu makin lambat. Suhu maksimum yang dicapai pada reaktor bawah yaitu 300oC dengan kecepatan putaran pengaduk 5 rpm. Diharapkan dengan pencapaian suhu ini, reaksi konversi biomassa dengan metode pirolisis untuk penelitian selanjutnya dapat tercapai.

Air pollution occurs when the air is mixed with contaminant substances in a high concentration. Air pollution can happen to both outdoor and indoor due to human activities and anthropogenic sources, such as printing, cooking, cleaning, smoking, and outside pollution that is carried away inside. One kind of air pollution substance is PMs or particulate matter. PMs can be found as coarse, fine, and ultrafine particles. Especially for the ultrafine particles, this type of PMs has a diameter of less than 0.1 µm. Ultrafine particles may enter the systemic circulation and affected child development. An air purifier is one of the methods to improve indoor air quality. Hence, this study aims to design a purification system of indoor PM 0.1 emission using an integrated filter consisting of activated carbon, a HEPA, an electrostatic filter, and an ionizer filter. The study used three different sources, such as cigarette smoke, mosquito coil, and insect repellent. These emissions were injected into an exposure chamber with a constant volume of 937.000 cm3, At the same time, the ultrafine concentrations before and after being purified were measured using a TSI P- Trak Ultrafine Particle Counter model 8525. The system works well to reduce ultrafine particles with the efficiency of 98 ± 1 % and CADR 29500 ± 35 cm3/s, respectively.

Volatile organic compounds or VOCs can be derived from many sources, like cooking, smoking, biomass burning, and motor vehicle emission. VOCs are a type of gas known to have a significant relationship with human health and air quality. It is necessary to have a monitoring system to determine VOC concentration in the surrounding environment. This study aims to develop a portable concentration measurement system for volatile organic compounds for different emission sources. The designed system was tested under different emission sources: cigarette smoke, mosquito coil, spray paint, and filtered ambient air. All measurements were carried out for ten minutes with a minute of the interval time for each sampling period. The measurement results show that the system has good responsibility and sensitivity to the VOC concentration. The range of VOC concentrations that can be detected by the system is from 0 ppm to 32 ppm. The system has a resolution of 0.001 ppm, with an accuracy of ±2 ppm.

Volcanic activity is a natural source of CO (carbon monoxide) and CO 2 (carbon dioxide), two powerful pollutant gases which have harmful effects on human health and the environment. The high concentration of CO and CO 2 has a potential risk to surrounding residents, especially in the source area. Malang, East Java, Indonesia, is a city that is surrounded by three volcanoes. The volcanoes produce CO and CO 2 in a significantly high concentration. This condition triggers the need for a reliable measurement system. Based on the needs, this study aims to design a CO and CO 2 concentration measurement system. The system was applied to measure the CO and CO 2 concentrations in three volcano areas: Mt. Welirang, Mt. Bromo, and Mt. Panderman. The system measures with a time response of fewer than 2 seconds with sensitivity o ±0.14 kΩ/ppm for CO measurement and ±0.05 V/ppm for CO 2 measurement and the accuracy ±0.04 ppm for CO and ±9.8 ppm for CO 2 . The system measurements range from 0 - 15 ppm for CO measurement and 300 - 550 ppm for CO 2 concentration with the resolution of 0.01 ppm for CO and 1.0 ppm for CO.

Particulate matters or PMs can be classified into different diameter sizes: ultrafine, fine, coarse, and total suspended particles. They are generated from many sources. One of them comes from volcanic activities. Thus, the objective of this study is to design a portable volcanic particulate matter concentration measurement system. This study used a Winsen dust sensor (model ZH03A) and a microcontroller (Arduino UNO). The system was tested in three different areas near Mt. Bromo (A1), Mt. Welirang (A2), and Mt. Panderman (A3) (East Java Province, Indonesia). PM concentrations were measured using the designed system consisting of a ZH03A sensor. The measured PMs had different particle size distributions: PM 1 (0.3 - 1 µm) and PM2.5 (1-2.5 µm). According to the performance test results, the system has good linearity and accuracy for the volcanic particulate matter concentrations with diameters of 0.3 µm to 2.5 µm. The system has PM 1 concentrations of 7 µg/m3, 3 µg/m3, and 5 µg/m3 for A1 to A3. Meanwhile, PM2.5 measurement results have concentrations of 11 µg/m3, 6 µg/m3, and 7 µg/m3 for A1, A2, and A3. The system works well in measuring all PM size distributions with a response time of fewer than two seconds. The system has a measurement accuracy of ±1 µg/m3 for PM 0.1 , ±1 µg/m3 for PM2.5 and range of 1 µg/m3 to 1,000 µg/m3, with a resolution of 1 µg/m3.

This article discusses the concept of da'wah nationalism in broadcasting Islamic values under the auspices of the Islamic boarding school developed by KH. Much. Imam Chambali. This study uses qualitative research with field research methods focused on the values of nationalism developed by KH. Much. Imam Chambali. The data collection instruments consist of interviews, documentation, and observations with the analysis technique of the Miles and Huberman model (data reduction, data presentation, and concluding). The results of the study illustrate that KH. Much. Imam Chambali carried out nationalism da'wah by planting and developing nationalism. How this is done can be seen clearly in three aspects. First, providing da'wah materials containing elements commemorating the services of heroes is expected to help foster a sense of nationalism. The second is an effort to inculcate an attitude of internal and inter-religious tolerance to create harmony. Third, acculturating the local language with its da'wah messages so that the da'wah message can be easily accepted by the community and as a tool to maintain nationalism in the era of globalization.

A large number of motor vehicles in the world have been linked to the increase of the emissions, such as particulate matters and gases. These pollutants, especially for the particulate matters with the diameter less than 0.1 micrometer or ultrafine particles, become detrimental thing to the natural environment and human health. There is a need to develop a better method to decrease the particles. Thus, one step ahead of the technological improvement in the transportation sector is the development of an emission filter applied in a motor vehicle exhaust system. According to this background, we developed an ultrafine particle filtering system based on an electrostatic principle using a direct current - high voltage. The filter is based on a electrostatic principle by using uses aluminum as the anode and cathode. This filter was tested under the different DC voltage of 100, 200, 300, and 400 Volt. The efficiency of the filter was tested by measuring the motor cycle ultrafine particles before and after applying the electrostatic filter. The particle concentrations were measured by using a TSI P-Trak Ultrafine Particle Counter model 8525. The result shows that the designed filter works well in reducing the ultrafine particles., with the efficiency of 7% to 46%. The filter efficiency depends on the applied voltage.

Hydroxyapatite (HAp) is a bioceramic that can be applied for bone tissue regeneration. The hydroxyapatite scaffold has poor biodegradation. To increase the biodegradation of HAp, we composited it with PVA, Chitosan, and PEG polymers, which have faster biodegradation properties. PVA/CS/PEG/HAp composites nanofibers as a scaffold in bone tissue engineering were prepared by electrospinning. The composition of HAp varied 0, 2, 3, 4, 5, and 6%. HAp was synthesized from natural deposits and characterized using X-Ray Diffraction (XRD) to obtain phase, crystallinity, and crystal size. Surface morphology and porosity of nanofiber composites were characterized by SEM-EDX. Previous studies without the addition of PEG produced less homogeneous nanofibers. Increasing the concentration of HAp and adding PEG could increase the average diameter of the nanofiber and reduce porosity. Composite biodegradation of PVA/CS/PEG/HAp was also evaluated. Biodegradation test was carried out by immersing the sample in Krebs solution prepared for 1-4 weeks, and the fastest mass reduction occurred in HAp (0%) and decreased with increasing concentration of HAp. This nanofiber HAp/CS/PEG/HAp composite can be applied as a scaffold in bone tissue engineering.

Fine particles are particulate matters having a diameter less than 2.5 µm, ubiquitous in ambient air and mainly resulted from many emission sources. Several epidemiologic studies have investigated fine particles that have a relationship with an inflammatory response deep in the lung and red blood cells. For these reasons, the interest in real- time monitoring of the concentrations in the ambient air has increased. In this study, a bare quartz crystal microbalance combined by an impactor, a fine particle filter paper, and a signal conditioning circuit was used to measure the fine particle concentration based on the frequency change. This study aimed to define the correlation between mass loading and frequency shift of the crystal. The mass of fine particles was calculated by multiplying the total of fine particles concentration, emission flow-rate, and measurement time. A Kanomax Digital Dust Monitor Model 3443 was used to measure the concentration of fine particles inside an experimental chamber with a volume of 12,000 cm3 for certain measurement times. At the same time, a bare quartz crystal microbalance with a fundamental frequency of 9.9780 MHz was connected to an oscillator and frequency counter to measure the frequency shift related to the fine particle concentration fluctuation. The results showed that the frequency shift of the crystal, to the fine particle mass, in which frequency decreases corresponding to the increasing amount of particle mass.

Air quality decreases due to the increase in air pollutants generated by motor vehicles that have a negative impact on human health. Generally, the pollutants can be gaseous and particulate matter. PM2.5 are particulate matters having diameters less than 2.5 µm, respectively. This research was aimed to design a measurement system of PM2.5 concentration. A PM NOVA SDS011 and a microcontroller ATmega328P were used as the sensor and the processing system. The principle of the sensor was based on the change of the particulate concentration to a voltage. The particulate PM2.5 concentration was displayed on an LCD. The system was completed by a LoRa SX1278 module to data communication. The performance of the system was tested based on the ability to measuring PM2.5 concentration and data communication in a varied distance. The result showed that the system worked well in measuring the PM2.5 concentration in the range of 0-1000 µg/m3. The resolution was 1 µg/m3. The system can be used to measure PM2.5 with a distance of up to 200 meters.

The Zinc oxide is well known as a direct wide bandgap semiconductor material with many promising properties for blue/UV optoelectronics, transparent electronics, spintronic devices and sensor applications. Controllable bandgap tuning is important to widen its possible applications. In the present work, we applied density functional theory to study bandgap tuning of ZnO by introducing Na atom and Cl atom. Sodium acts as p-type doping, while chlorine acts as n-type doping for ZnO. The effect of Na and Cl doping in the study was calculated using the Density Functional Theory (DFT) method. The results indicate that ZnO, which is a natural n type semiconductor when doped with p type, has an increase in bandgap, on the contrary, doping with n type decreased its bandgap

This paper investigates the energy spectrum of a periodic one-dimensional Coulomb potential. The Schrödinger equation is solved numerically by our newly developed filter method (Phys. Rev E 96(3), 033302 (2017)). We observe that the energy spectrum can be obtained with a limited number of lattice. The results show the presence of an energy band structure as a function of lattice width and edge width. The comparison with the other potential model is also discussed.

A Stanene, is a two-dimensional material composed of tin atoms arranged in a single hexagonal layer, in a manner similar to graphene. First principle studies based on density functional theory were performed to investigate the effects of hydrogenation and Al/P doping on electronic structure and magnetic properties of stanene. Hydrogenation opens the bandgap of stanene and changes it from nonmagnetic to the ferromagnetic material through H 1s states and Sn 5p states hybridization. Al/P atom at hollow site prevent electrons of adjacent Sn atoms to connect so that inducing unpaired electrons. The combination of hydrogenation and Al/P doping increases its magnetization. The sequence based on its magnetic moment from small to large is as follows: pure stanene, Al-doped stanene, P-doped stanene, hydrogenated stanene, Al-doped hydrogenated stanene, and P-doped hydrogenated stanene. The controllable transformation from nonmagnetic metallic to a magnetic semiconductor is a key requirement for materials to be used as spintronic materials. Thus, these results may shed light on designing the stanene-based electronic and spintronics materials.

Computational studies of silicene, which is a two-dimensional silicon material with honeycomb structure, has been carried out using Density Functional Theory Calculation. This study was aimed to determine the effects of doping gallium (Ga) atom and arsenic (As) atom on the magnetic properties of hydrogenated silicene. The results showed that pure silicene has very small magnetic properties, can be considered as non-magnetic. The process of hydrogenation on silicene changes it to become a magnetic material. The effects of Ga/As dopant on the magnetic properties of hydrogenated silicene depends on positions of Ga/As atom. Silicene with As atom at hollow site has the highest magnetic moment of 0.0592 μB . This value increases from the magnetic moment of hydrogenated silicene magnet by 104%.

The population of the motor vehicles, including a motorcycle in the world has been growing from year to year. It also has been linked to the increase of pollution to the ambient air due to the gaseous and particulate emissions, such as PM1.0, PM2.5 or fine particle, PM10 or coarse particle, SOx, NOx, and many other forms. As a need to clean the air, it is important to develop a filtration system of particulate matters that is applied in a motor vehicle exhaust system. In this research, the electrostatic filters were made of aluminum plates as anodes and cathodes in order to create an electric field. The voltage was varied of V1 (100 Volt), V2 (200 Volt), V3 (300 Volt), and V4 (400 Volt). These filters were installed on the motorcycle exhaust system and tested for 30 minutes. Coarse particle (particulate matter with the diameter less than 10 µm) concentrations before and after passing through the electrostatic filter were measured using a Nova PM Sensor model SDS011 and a microcontroller. The results show that the filter efficiency is a time and voltage-dependent. The highest efficiency (58%) was obtained at the voltage of 400 Volt, V4. On the other side, V1 generated the lowest efficiency (5%).

Increasingly strict air pollution regulations along with global warming issue have peeked the interest in cleaner emission emitted by motor vehicle. In line with this, this study was aimed to develop a particulate filtering system based on an electrostatic principle for particulate matter with the diameter less than 2.5 μm, as known as a fine particle, and to test the performance of the filter. The filter consists of aluminum anodes and cathodes as the electrostatic electrodes. These electrodes were placed into the filter frame and installed on a motor vehicle muffler. The test was conducted to estimate the filter performance by measuring particle concentrations before and after using the filters. The filter was tested under four different electrostatic voltages:V1100 Volt,V2200 Volt,V3300 Volt, andV4400 Volt. The results show that the filter can reduce fine particle concentrations with the best efficiency of 50%, 60%, 62%, and 68%, respectively forV1,V2,V3, andV4. Filter performance was directly influenced by the applied voltage and the time of the test.

Materials with Mexican-hat electronic energy dispersions emerging from heterostructures, substrate effects, or spin–orbit couplings are believed to exhibit excellent thermoelectric properties due to its van Hove singularity of density of states in two-dimension. However, within a constant relaxation time approximation, we disprove this belief and we find that the singularity effect is cancelled down by the group velocity contribution in the thermoelectric transport distribution. Nevertheless, the band parameters can still be optimised to reach thermoelectric figure of merit larger than 2 in a wide bandwidth, thus keeping the potential of materials with Mexican-hat bands for thermoelectric applications.

The paper presents a method for simultaneous computation of eigenfunction and eigenvalue of the stationary Schrödinger equation on a grid, without imposing boundary-value condition. The method is based on the filter operator, which selects the eigenfunction from wave packet at the rate comparable to δ function. The efficacy and reliability of the method are demonstrated by comparing the simulation results with analytical or numerical solutions obtained by using other methods for various boundary-value conditions. It is found that the method is robust, accurate, and reliable. Further prospect of filter method for simulation of the Schrödinger equation in higher-dimensional space will also be highlighted.

Particulate matters with the diameter less than 2.5 µm or PM2.5, have been known to the health adverse. The developing of a measurement system of PM2.5 with a high precision has become a challenge in the last decade. We design the system using a NOVA SDS011 sensor to measure PM2.5 concentration. The problem is that the sensor has a capacity to measure particulate matter in the range of 0.3 to 10 µm, meanwhile we would like to design the measurement system of PM2.5 with the high precision. Another this that we address is how to optimize the sensor. A factor influenced the sensor optimization is a sample compartment. In this paper, we present the PM2.5 measurement system with the different compartments. The PM2.5 measurement system was calibrated using the 3443 Kanomax dust monitor. The result shows that the system works well with the compartment is important factor to increase the precision.

A low cost particulate matter measurement system has been designed to quantify the concentration in the air. The device has been built up by using a PM2.5 sensor. The sensor signal is processed and transfer to an Arduino UNO microcontroller. A long-range wireless communication is attached in the system for a distance measurement. The system has been validated using a 3522 Kanomax dust monitor model. The system was tested in the distance to characterize the performance. The system works properly to measure PM2.5 concentration. The PM2.5 concentration is presented in the average value of the 30 seconds sampling measurement. The system is controlled by using humidity and temperature sensor to avoid any damage caused by an environment condition. The maximum humidity and temperature for the system is restricted to 70% and 50°C respectively. The measurement system is accomplished to a NRF2401 radio module to allow to collect data remotely. In conclusion, the proposed system works well to measure PM2.5 in the environment. The system has an ability to measure particulate matter with maximum concentration of 750.0 μg/m3 with the resolution of 0.3 μg/m3.

Our recent developed filter method (Phys. Rev E 96(3), 033302, 2017) is applied here to investigate the energy spectrum and their corresponding wave function of one dimensional crystal. The periodic one dimensional potential is modelled by using one dimensional periodic harmonic oscillator, with variation on oscillator potential depth, quasi-potential depth, and crystal width. For energy less than the potential depth of the oscillator, the computational results reveal that the periodic harmonic oscillator produces a discrete spectrum, as the energy spectrum of a single harmonic potential. However, for energy almost equal to or greater than the depth of the potential oscillator, the periodic harmonic oscillator demonstrates the existence of pattern similar to energy band in crystal.

In view of the controversy on atomic stabilization, two different methods for numerically integrating the time dependent Schrodinger equation (TDSE) are studied and compared, i.e. the direct integration on spatial grids (DISG) and the eigenstate expansion method (EEM) with exact treatment of free–free dipole matrix elements (FFDME). The simulations show that both methods provide the above threshold ionization (ATI) spectra and wavepacket densities that agree very well each other. This comparison is important regarding a claim that DISG may suffer a numerical instability due to the lack of FFDME [T. Mercouris et al., J. Phys. B 29 (1996) L13]. Using the eigenstate expansion method, a series of simulations with high frequency, ultra intense laser were carried out. The results show that the ionization yield first increases, and then decreases or stabilizes when intensity goes to a value beyond the turning point. Simulations using various pulse forms prove that the stabilization presents and is not subject to the pulse form.

A pressure gradient method for spectral broadening of intense-femtosecond laser pulses in gas-filled hollow fiber is proposed. The simulations using input energy of 6 mJ and pulse duration of 40 fs have shown that using the same value of ∫ p(x)dx, the energy transmittance can be enhanced by a factor of 25% compared to that of using constant gas pressure while the global spatial phase is also improved.

The nonlinear susceptibility of atoms interacting with an intense laser field has been investigated using numerical solution of the time-dependent Schrödinger equation. It was found that the behavior of nonlinear susceptibility strongly depends on the intensity; it increases linearly in low intensity regime (Kerr nonlinearity), then saturates at higher intensity. Furthermore, it has also been found that the nonlinear susceptibility is substantially influenced by the onset of ionization.

A method to solve the time-dependent Schrodinger equation of the hydrogen atom and hydrogen-like ions in intense laser pulses, based on an expansion of the total wavefunction in bound and continuum eigenstates of the unperturbed system, is presented. The problem arising from the well-known singular continuum-continuum dipole matrix elements is fully analyzed and resolved by a combination of analytical integration of the singular contribution and a numerical integration of the singularity-free difference contribution. Unlike in usual finite-difference methods using a spatial grid, in the present approach, probability amplitudes of bound-bound, bound-free and free-free transitions are obtained without additional calculations. The efficacy and accuracy of the present method is demonstrated by calculating above-threshold ionization spectra (ATI) and high harmonic generation spectra (HHG) for different values of laser parameters. Finally, the results obtained by using the present method are compared with that of a finite-difference method involving a spatial grid. The present method proves to be an efficient alternative to the usual spatial grid methods for the solution of the time-dependent Schrodinger equation and the estimation of ATI and HHG spectra in case of intense laser pulses. (C) 2001 Elsevier Science B.V. All rights reserved.

We present results from interaction of helium with intense, femtosecond laser pulses. Using spectral methodfor selecting the harmonics, it can be shown that under certain condition, a single femto or subfemtosecondharmonic pulses as well as train of attosecond pulses can be generated from femtosecond intense driving field.

In this paper we treat by entirely ab initio methods, a number of phenomena in nonlinear dynamics in intense laser fields. In particular, we apply the recently developed Floquet-coupled-channel (FCC) method to investigate the phenomenon of adiabatic stabilization and formation of stabilization windows in hydrogen atom, as well as the frequency and intensity dependence of nonlinear-detachment process in hydrogen negative ion. Moreover, a solution is given, with examples, to the methodological problem of consistently evaluating the ATI-spectrum within the Floquet theory. Next, direct simulations are carried out to determine the influence of stabilization on the ATI-spectrum and on the bound state occupation probabilities of H-atom. Finally, the time-scale of formation of ATI-peaks is investigated and shown to be of the order of the rise-time of the pulse.

The dynamics of nonlinear optical conversion in the high-intensity femtosecond pump regime has been studied in gaseous media over a wide pressure range. The existence of two different types of optical supercontinua, structured and structureless, has been found in a number of atomic (argon, krypton) and molecular (methane) gases. The structured optical supercontinuum exhibits a typical oscillationlike spectral structure, resulting from self-phase modulation in neutrals and plasma. The structureless optical supercontinuum is completely dense, and its main properties cannot be explained within the self-phase modulation mechanism. The structureless optical supercontinuum is attributed to Bremsstrahlung radiation from electrons that tunnel through the bound potential inside the atoms or molecules under a strong optical field. The basic properties of the structureless optical supercontinuum have now been revealed experimentally.

We investigate the possibility of optical pulse compression of high energy ultrashort laser pulses in an argon-filled planar waveguide, based on two level coupled mode theory and the full 3D nonlinear Schrödinger equation. We derive general expressions for controlling the spatial beam profile and the extent of the spectral broadening. The analysis and simulations suggest that the proposed method should be appropriate for optical pulse compression of ultrashort laser pulses with energies as high as 600 mJ.

A proposal for spectral broadening of tens milli Joule femtosecond laser pulses in an argon-filled hollow fiber is presented. The simulation results show that themethod could be useful under conditions where ionization plays a greater role and that it can be used to control plasma-induced spectral broadening.

The application of a Herriot multiple-pass cell (MPC) filled with neon for spectral broadening of a femtosecond, intense laser field has been studied theoretically. The simulation using 50 mJ, 60 fs laser pulses with a center wavelength of 780 nm has shown that relevant spectral broadening can be obtained after 10 passes of the pulse, yielding a compressed pulse with a width of 4.5 fs and an energy of 25 mJ.

We present a systematic study of filamentary ultrashort laser pulses in air, through numerical solutions of the nonlinear Schrödinger equation for various contributions of the delayed Kerr nonlinearity. The results show that a relatively larger contribution of the delayed Kerr nonlinearity will lead to a longer stable filament. This is explained from the transfer of the nonlinear contributions from the frontier part to the back of the pulse and the counterbalanced action of the negative plasma induced nonlinearity by the delayed Kerr nonlinearity in the trailing part of the pulses. Furthermore, effect of ionization on the stability of the filament is investigated. Two formulas are used to generate the data of the ionization, i.e., the Perelemov, Popov, and Terent'ev (PPT) and the Ammosov, Delone, and Krainov formula. It is found that simulation with higher ionization rate (PPT) could generate a more stable and longer filament.

We investigate the nonlinear susceptibility of noble gas atom interacting with intense laser field. The solution is obtained by solving the time dependent Schrodinger equation. It is shown that the behavior of nonlinear susceptibility strongly depends on the intensity; it increases almost linearly in low intensity regime, then becomes saturated at higher intensity. Furthermore, at intensity beyond the saturation value, the nonlinear susceptibility is substantially induced by the ionization of the atom, leading to rapid fall of the nonlinear refractive index.

The nonlinear susceptibility of atomic hydrogen interacting with an intense laser field has been investigated using a numerical solution of the time-dependent Schr\"odinger equation. It was shown that the behavior of the nonlinear susceptibility strongly depends on the intensity; it increases linearly in the low-intensity regime (Kerr regime), then saturates at a higher intensity. Furthermore, it was also shown that the nonlinear susceptibility is substantially induced by the ionization, whose magnitude is simply related to the density of the ionized electrons. By analyzing the calculated refractive index, it was found that the refractive index induced by ionization is 7--20 % smaller than that derived from the plasma frequency.

The propagation dynamics of intense femtosecond laser pulses in argon have been investigated theoretically and the results are compared with experimental data. It was found that in the initial stage the pulse propagates with the focal point moving ahead of the original one. The central beam of the trailing part experiences defocusing owing to ionization by the leading part and then regains self-focusing provided by power from the outer part. On propagating further, a quasistable balance is established between self-focusing and defocusing due to ionization-induced nonlinearity and diffraction, causing the beam to propagate in a self-guided mode. Furthermore, it was shown that the front of the split pulse decays faster, while the trailing edge experiences self-focusing and self-defocusing until a self-guided propagation mode is achieved. Multiple pulse splitting and shortening as a result of the dynamics near the focal point were also observed.

We investigate a simply corrected Keldysh-Faisal-Reiss (KFR) rate formula for laser-induced ionization of atoms in the nonperturbative intensity domain. Predictions of the formula are compared, first, with ab initio Floquet calculations, which show good agreement in the nonperturbative intensity domain for not too short wavelengths. Second, they are found to agree with the results of numerical simulations for the H atom, provided the pulse lengths are not shorter than three field cycles, so that the adiabatic rate becomes a valid parameter. Finally, total single-ionization yields predicted by the present model are compared with 36 different experimental data sets for He, Ne, Ar, Kr, and Xe, covering both linear and circular polarizations, and different wavelengths, pulse durations, and intensities; the results show a remarkable overall agreement with the data.

An implicit algorithm for integration of the three-dimensional (3D) time-dependent Schrodinger equation of an atomic system interacting with intense laser pulses is developed. It is based on a matrix iteration of the Crank-Nicholson approximant to the short-time propagator using the total Hamiltonian (unsplit) of the system directly. To test the method, 3D Schrodinger wave-packet propagation is carried out, and so-called above-threshold ionization and high-harmonic generation spectra for atomic hydrogen irradiated by intense laser pulses are obtained. They are also compared with that obtained using the popular split-operator method. The present algorithm is shown to provide an alternative to the the split-operator method, and proves to be more efficient in all the cases studied here. A procedure for optimizing the maximum grid size is also given, and its usefulness is illustrated. [S1050-2947(99)06409-4].

The possibility of modulation of an Autler-Townes doublet structure in an atomic continuum by changing the phase difference between two incident femtosecond laser pulses is investigated theoretically. Numerical simulations are carried out by solving the three-dimensional time-dependent Schr\"odinger equation for a Na atom interacting with a two-color field, a fundamental, and its second harmonic. It is found that a sinusoidal modulation of the individual members of the doublet, as a function of the phase difference, can be achieved at low intensities of the order of ${10}^{10}{\mathrm{W}/\mathrm{c}\mathrm{m}}^{2}.$ Such modulations of the sharply defined electron currents (where the width is of the order of the fine structure of the Autler-Townes levels) may be detected by high-resolution photoelectron spectroscopy. It is also shown that at a higher intensity of the order of ${10}^{12}{\mathrm{W}/\mathrm{c}\mathrm{m}}^{2}$ the amplitude of modulation diminishes, indicating that lower intensities are to be preferred for the present purpose.

We report on the compression of intense ultrashort laser pulses for the purpose of producing few-cycle optical pulses at the multimillijoule level by using a planar waveguide (PWG). The PWG is composed of two parallel glass slabs separated by a gap of 100 microm and mounted in a gas chamber filled with a noble gas. In comparison with the conventional hollow-fiber-based pulse compression technique, the use of a PWG enables the injection of high-energy ultrashort pulses, because the input laser beam is confined only in the lateral direction perpendicular to the waveguide plane. Using this technique, we demonstrate the generation of 12 fs, 2 mJ laser pulses in an argon-filled PWG.