Double Ring Research Articles

Graphene based highly sensitive refractive index sensor using double split ring resonator metasurface

Graphene based highly sensitive refractive index sensor using double split ring resonator metasurface

ANALYSIS OF INFILTRATION RATE OF RAINFALL IN MOUNT PANCAR, BOGOR, WEST JAVA

Infiltration rate and rainfall are one of the parameters in determining water catchment areas. In an area that has a high level of rainfall, it is very good to be a water catchment area. Water catchment areas must be maintained and protected so that they can be used to incrase groundwater reserves and prevent flooding, so a spatial plan is needed in determining water catchment areas. This study aims to determine the rate of infiltration in the ara of Mount Pancar, Bogor, West Java. Infiltration rate data was collected directly in the field using a double ring infiltrometer and rainfall data was obtained from BMKG data at Citeko Station. The final result of these data will be made a map of the infiltration rate and rainfall map. The results of the study in the study area obtained an infiltration rate of 0,096 m/day – 0,553 m/day with rainfaal of more than 3000 mm/year. From these data, it can be concluded that the rate og infiltration and rainfall are closely related to each other in determining water catchment areas.

Studi Laju Infiltrasi Pada Lahan Irigasi Gumbasa (Studi Kasus di BGKn 38, 42 dan 51)

The 2018 earthquake that shook the city of Palu and surrounding areas with the power of 7.4 MW triggered liquefaction in several locations. Earthquakes and liquefaction that occurred caused damage to Gumbasa’s irrigation canals and some paddy fields. This study was conducted at three points in the paddy fields which 2 points located in the Soulowe village and Sidera village, District of Dolo and one is located in the Lolu village, District of Biromaru. This study aims to determine the infiltration rate in the residents’s paddy fields which have not been planted with paddy for a long time. This is because until the data retrieval performed, Gumbasa irrigation network has not functioned and still under repair. Data were collected using a Double Ring Infiltrometer measuring instrument. The results obtained from this study for constant infiltration rate of BGKn 38 = 1.27 cm/hour, BGKn 42 = 1.10 cm/hour and BGKn 51 = 0.75 cm/hour, which all three are classified as a rather slow with a constant infiltration rate ranging from 0.5 to 2 cm/hour. For the difference in fc values, BGKn 38 and BGKn 42 at 0.17 cm/hour and BGKn 42 and BGKn 51 at 0.35 cm/hour, so that BGKn 38 and BGKn 51 is 0.52 cm/hour. Meanwhile, the value of the difference f0 from the three points is BGKn 38 with BGKn 42 at 3.82 cm/hour and BGKn 42 with BGKn 51 at 4.43 cm/hour, and BGKn 38 with BGKn 51 is 0.61 cm/hour.

A Comparative Study to Assess the Suitable Models for Predicting the Infiltration Rate in an Arid Region

Surface infiltration plays an important role in watershed management and flood forecasting; Furthermore increase the efficiency of irrigation system and reduce water losses during the irrigation process. Experiments carried out on the Wadi AL-Ratga of the western desert, Iraq during 2019; which had been selected as a study area. The infiltration rate data were collected using double ring infiltrometer at selected ten points of the selected study area. The duration of double ring test ranged between 30 minutes to one hour based on the infiltration speed in the soil, about 6 to 12 readings were recorded for the infiltration rate at each points. The aim of this paper is to check the ability of the common infiltration models such as Horton’s, Kostikov’s and Philip’s to accurate estimated infiltration rate. These models were fitted to the observed infiltration data for estimation of models parameters and to find appropriate model for this region. Horton’s infiltration model’s parameters such as infiltration decay constants ’k’ And the value of infiltration capacity at onset of infiltration (fo) had been calculated in the ranges of 3.38-6.97 hr-1 and 21 to 47.8 cm.hr-1; respectively; for all the ten points. Philip’s infiltration model’s parameters such as the values of conductivity constant ‘A’ and sorptivity ’S’ were obtained in the ranges of 3.48-12.49 cm.hr-1 and 9.96 to 17.2 cm/hr0.5; respectively. Similarly; the Kostikov’s model’s parameters ‘a’ and ‘b’ were obtained in the range of 8.85-24.38 and 0.732-0.829; respectively. Based on results of infiltration models at the selected points the predicated parameters have realistic capability predication. The results showed that all models provided the acceptable values for Root Mean Square Error (RMSE) as1.45, 2.01, 1.88 cm.hr-1 for Horton’s, Kostikov’s and Philip’s model; respectively; The highest model efficiency (ME) as 99% for all models; and the maximum Relative Error (RE) values as 16% at all points except point 2 was calculated as 21%. This indicated that infiltration can be well-described by the Horton’s model little more than other models at the study area.

Active wavefronts control with graphene-functionalized terahertz Metasurfaces

Metasurfaces, a new kind of artificial subwavelength structures, have exhibited unprecedented capabilities in wavefront control of electromagnetic waves. Currently, a series of active metasurfaces have been explored for engineering applications in anomalous refraction, ultrathin flat lens, holograms, and vortex beam generation, However, to date, most reported metasurfaces are mainly concentrated on active control on the polarization conversion and wavefront of circular polarized waves. Here, graphene-functionalized metasurfaces consisting of metallic double split ring resonators integrated with graphene (G-DSRRs) are proposed to actively control polarization conversion and wavefronts of linearly polarized waves at the terahertz region. By carefully designing spatially phase profile, anomalous reflection of linearly cross-polarized terahertz waves is demonstrated in a broadband range of frequencies. Moreover, the amplitude of the anomalous reflection terahertz wave can be dynamically tuned by varying Fermi energy via electrically doping graphene. Based on the tunable graphene-functionalized metasurface, several polarization conversion metasurface devices including vortex beam generators, invisibility cloaks, and metalens, are successfully designed and numerical results show that their amplitudes can be actively tuned to a significant extent by doping graphene. Therefore, such graphene-functionalized metasurfaces may have potential applications in THz telecommunications, high-resolution terahertz displays, and advanced THz imaging devices.

Achieving Continuous Stable Beam Steering with Gain Enhancement Using a Graded-Index Metasurface Lens

In this paper, the design of an ultrathin highly transmissive angular graded-index metasurface (AGIMS) lens is proposed, and a beam steerable high-gain low-profile lens antenna is designed using AGIMS lens and microstrip patch antenna (MPA) radiator operating at 10.10 GHz. An ultrathin graded-index metasurface lens is designed using fundamental unit cells and their modulated forms. The direction and gain control of the microwave radiator’s beam, using a designed modulated metasurface lens with doubled-sided double circular ring resonator as a fundamental unit cell, is presented. The uniform radial and linear movement of AGIMS in the step of 12 mm steer the radiated main beam of MPA continuously in a conical plane from −40° to +40° with a maximum measured broadside gain of 13.15 dBi and minimum broadside gain of 11.80 dBi at 10.10 GHz frequency, indicating maximum and minimum gain enhancement of 8.40 and 7.0 dB in −40° and 0° direction, respectively. The angular movement of AGIMS over the MPA radiator at the centre point results in beam steering from −25° to +25° continuously with a maximum gain variation of 2 dB and a maximum measured gain from 10.00 dBi to 12.00 dBi, indicating gain enhancement of 5.25 dB to 7.25 dB. Using AGIMS, the stable broadside radiation characteristic with beam steering and continuous gain enhancement is achieved. The measured and simulated results are in good agreement.

Impurity effect on the ground state binding energy of a fully coupled polaron in a double ring shaped quantum dot

Double rings shaped quantum dot (DRSQD) is one of the important theoretical models for studying the properties of quantum dots (QD) in recent years, due to the superiority of its own double rings shaped potential (DRSP). Moreover, the influence of impurities on material properties is of great significance, because the presence of impurities can greatly affect the electro-optical properties of it. Ingeniously combining and exploring two methods of the Lee–Low–Pines unitary transformation (LLPUT) and linear combination operation (LCO) from both weak coupling limit (WCL) and strong coupling limit (SCL), the electrical properties of the fully coupled polaron (FCP) in DRSQD under the influence of impurities are indirectly considered. Under both the WCL and the SCL, the relational expressions of the polaron's vibrational frequency (VF), ground state energy (GSE) and ground state binding energy (GSBE) versus the parameters of the DRSP (PDRSP), the frequency of the DRSP (FDRSP) and the strength of the Coulomb's impurity potential (SCIP) are deduced, numerically calculated and analyzed. Besides, the contrast characteristics of the polaron's properties are given in the case of with or without impurity and under the WCL and the SCL. Simultaneously, we also compared the results of this paper with those of other literatures. The characteristic of the FCP in DRSQD under the influence of impurity effect is of great significance, because it provides new insights and references for the experimental design based on DRSQD.

Detecting gravitational lenses using machine learning: exploring interpretability and sensitivity to rare lensing configurations

ABSTRACT Forthcoming large imaging surveys such as Euclid and the Vera Rubin Observatory Legacy Survey of Space and Time are expected to find more than 105 strong gravitational lens systems, including many rare and exotic populations such as compound lenses, but these 105 systems will be interspersed among much larger catalogues of ∼109 galaxies. This volume of data is too much for visual inspection by volunteers alone to be feasible and gravitational lenses will only appear in a small fraction of these data which could cause a large amount of false positives. Machine learning is the obvious alternative but the algorithms’ internal workings are not obviously interpretable, so their selection functions are opaque and it is not clear whether they would select against important rare populations. We design, build, and train several convolutional neural networks (CNNs) to identify strong gravitational lenses using VIS, Y, J, and H bands of simulated data, with F1 scores between 0.83 and 0.91 on 100 000 test set images. We demonstrate for the first time that such CNNs do not select against compound lenses, obtaining recall scores as high as 76 per cent for compound arcs and 52 per cent for double rings. We verify this performance using Hubble Space Telescope and Hyper Suprime-Cam data of all known compound lens systems. Finally, we explore for the first time the interpretability of these CNNs using Deep Dream, Guided Grad-CAM, and by exploring the kernels of the convolutional layers, to illuminate why CNNs succeed in compound lens selection.

Thermal Elastohydrodynamic Lubrication Analysis of High-Speed and Light-Load Rolling Bearing with Double Rings Rotation

Thermal Elastohydrodynamic Lubrication Analysis of High-Speed and Light-Load Rolling Bearing with Double Rings Rotation

An open double ring antenna with multiple reconfigurable feature for 5G/IoT below 6GHz applications

In this paper, we proposed a hybrid or compound reconfigurable antenna using three PIN diode switching to achieve the different types of reconfiguration: frequency and radiation pattern. Based on an open ring structure with the varied active PIN diodes, the proposed antenna radiation pattern can scan a beam along with one of five directions with the same operating frequency. Depended on the number of active PIN diodes, the antenna operating frequency also can switch to two of six bands which are 1.9 GHz, 2.4/2.6 GHz, 3.5 GHz, 5 GHz, and 5.6 GHz. All frequency bands are popular ones of wireless communication as well as 5G/IoT applications. In addition, the antenna gets a compact size of 30mm *30 mm*1.6 mm and wide bandwidth due to using the radiating shape of a double ring. All details of antenna design are optimized by CST software, and the simulation results agree well with the measurement results.

ANALYSIS OF INFILTRATION RATES OF SOILS ON THE INNER SLOPES OF THE LAKE SFÂNTA ANA CRATER

The present study consists of the comparative analysis of infiltration rates of soils under different land-cover conditions (dirt trails, grass plots and different types of forest stands) on the inner slopes of the Sfânta Ana crater, the catchment area of Lake Sfânta Ana in Romania. According to historical data, the depth and the surface of Lake Sfânta Ana have been undergoing significant changes during the last century, it lost in depth and the surface area shrunk approximatively 1,5 hectares. The losses are considered to be the consequences of the sedimentation as a result of the inflow processes from the catchment area, reduction of water level and eutrophication. The assessment and comparative analysis of steady infiltration rates of soils under different land-use categories in the catchment area were carried out to identify the possible sources of generation of surface flows responsible for sediment transport towards the lake using In Situ determinations with Double Ring Infiltrometers (DRI). Statistically significant differences were found between samples collected from grass plots, forests and the dirt trails, and within different forest stand structures. Results show that dirt trails and grass plots can be held responsible for the generation of surface flows. The main cause of low infiltration rates is soil compaction. Different forest stands are characterized by steady infiltration rates with high values and therefore provide effective protection. High forest coverage must be maintained in the crater, the problem of soil compaction on grass plots and dirt trails must be addressed.

Programmable wavelength filter with double ring loaded MZI

We propose a novel filter circuit that incorporates a double ring resonator with a balanced Mach–Zehnder interferometer (MZI). The circuit has a response equivalent to a conventional ring loaded MZI filter, but with added flexibility in terms of configurability. The second-order filter can also be cascaded to realize higher-order filters. The circuit incorporates a two-stage input and output coupler to further reduce the effect of dispersion. A combination of local and global optimization strategies to program the filter, using tailored objective functions, have been tested in simulation and experiments. To our best knowledge, this is the first time a global optimization strategy is directly used in ARMA filter synthesis and simulation without any additional requirement. We further extend the optimization strategy into experiments and demonstrated its use in practical case for programmable filter circuits.

Preparation of Kenaf Biochar and Its Adsorption Properties for Methylene Blue

The toxic dyestuffs from printing and dyeing wastewater have caused serious damages to the ecological environment, thus exploring effective methods to remove them having become a key topic. Here, a series of biochar samples were synthesized form kenaf to adsorb methylene blue (MB), which was acted as the dye representative for the test of adsorption capacity due to the presence of abundant double bond and aromatic heterocyclic ring. By tuning the raw materials and pyrolysis temperature, a super adsorption capacity about 164.21 mg·g–1 was obtained over the biochar that pyrolyzed at 700°C with the kenaf fiber as raw material. Through the physical adsorption, elemental analysis, FTIR spectra and NH3-TPD, it was found the high surface area and pore volume of biochar played a key role in the adsorption of MB, and the acidic sites would also assist the adsorption process. Besides, the adsorption kinetic model was fitted and calculated, implying the MB physically adsorbed on the biochar rapidly and then occurred chemical adsorption on the acidic sites. In addition, through KBC700 recycling experiments, it was found that kenaf biochar had a good binding force to MB, which effectively avoided secondary pollution. This work provides important insights for the adsorption mechanism of MB by biochar, also offers some guidance for the further synthesis of biochar from various biomass.

Design of Low Crosstalk Double Coupling Ring Assisted 6-LP Fiber

Design of Low Crosstalk Double Coupling Ring Assisted 6-LP Fiber

Ultrawideband RCS Reduction of Planar and Conformal Surfaces Using Ultrathin Polarization Conversion Metasurface

A metasurface-based polarization converter for ultrawideband radar cross-section (RCS) reduction of planar and conformal surfaces is presented in this paper. Initially, a polarization converter is designed which consists of a modified concentric double (MCD) square ring resonator-based unit cell along with an air gap in between the substrate and the ground plane. This air gap enhances the polarization conversion bandwidth (PCBW) of the converter. An ultrawide PCBW ranging from 6.3 – 20.5 GHz (106%) is obtained with a high polarization conversion ratio (PCR) of 0.9 for normal incident EM waves. The conversion efficiency is also found to be stable for oblique incidences over the aforementioned band with a PCR of above 0.8 upto ±35° angles of incidence. Later on, a checkerboard configuration of the polarization conversion metasurface (PCMS) array and its mirror array is applied on a planar as well as on a cylindrical conformal surface for reducing the radar cross section (RCS). It is observed that a consistent 10 - dB co-polarized monostatic RCS reduction is achieved with the planar PCMS surface over an ultrawideband (5.5 – 20.5 GHz). Even with the cylindrical surface, nearly 10 dB RCS reduction is obtained upto central angles of 60° over a wideband. Both the structures are simulated and measured after fabrication, and a reasonably good agreement is obtained between them.

Determination of Infiltration Rate under Different Levels of Compaction by the Use of Double Ring Infiltrometer, A Case of Kagera Sugar Limited (KSL)

Irrigation is a major factor in sugarcane growing. Unquestionably, sugarcane is one of the most Water - demanding crops after rice. The amount of water recorded from rainfall or irrigation systems in a given field are always considered as uniform despite of heterogeneous condition within the field. The application of water in the soil is one but the uptake by plant is the most side of consign. Water uptake by plant which is among of the root function, is mainly influenced by infiltration rate. Other side of these is right to say, any hindrance factor to infiltration rate and its capacity is primary killer for plant growth. Soil compaction is one of greatest factor which hinder water percolation into the ground as it deform soil structure. In infiltration test conducted at 6P4D shows the statistical difference between infiltration rate in compacted and non-compacted portions. The highest and lowest infiltration rate recorded was 383mm/hour to 116mm/hour and 220mm/hour to 35mm/hour in non-compacted and compacted portions respectively. Once the data were subjected to ANOVA using GenStat software was found to be statistically difference at 5% level of confidence. Being in a side of quantifying its consequences will help to make friendly decision in our farming system and irrigation scheduling in order to avoid water loss through runoff and flooding as a result of poor infiltration. The main purpose of this writings is to examine quantitatively on how compaction influence infiltration rate and come-up with recommendation such as Controlled Traffic system.

Thermal-optic tuning cascaded double ring optical sensor based on wavelength interrogation

Based on the Vernier effect of the cascaded double ring resonator (CDRR) sensor, a sensor consisting of a microfluidic control system, a sensing ring, and a reference ring with a micro-heater for thermal tuning is proposed in this paper. In wavelength interrogation, a broadband spectrometer or a large tunable range laser is not required. The shift of the output spectrum caused by the refractive index change of the sample is converted into the change of the electric power by the thermal tuning heater. Due to the Vernier effect, the sensitivity of the sensor is 20 times higher than that of the single ring. The spectral envelope of the thermal-optic tuning of the sensor was fitted by a Gaussian function in the wavelength range of 8 nm. The experimental results showed that the sensitivity was 33.703 W/RIU, and the limit of detection was 1.34×10−5 RIU.

SRPSKO VOJNO UTVRĐENjE SA KOMPLEKSOM VOJNIH BUNKERA I MAGACINA IZ XIX VEKA KOD BABUŠNICE

The system of bunkers and warehouses near Babušnica, with large breastworks, was built for distinctly defensive purposes in the period from 1890-1893. It was built during the time of King Aleksandar Obrenović as part of an important defensive belt in the border area towards Bulgaria. It is very well preserved. It is a fortunate circumstance that the fortress “Šanac” was never used in war. The bunker complex made of hewn stone was built on the Jeremija hill above the villages of Donje Striževac and Donje Krnjino near Babušnica. It consists of 10 bunkers in a row with a central entrance gate that leads to the central part of the complex where they are located, 4 more independent bunkers/warehouses are individually arranged. This central part is reinforced with a double ring of earth trenches. On the front side, in front of a row of ten bunkers, a defensive stone wall was built, oriented towards Bela Palanka. The defense system around Pirot, better known as the “Pirot Fortified Camp” for possible defense against a Bulgarian attack, was created at the end of the 19th century. It consisted of the localities “Jarčar”, “Božurata”, “Nišava Valley”, “Šabanov Trap”, “Crni Vrh”, and “Jeremija”, which was established as an immovable cultural asset-cultural monument, and the Institute for the protection cultural monuments in Nis is territorially responsible for its protection. The cultural monument is an exceptional example of the knowledge, skills, expertise and capabilities of the engineering units of the Serbian army of that time.

Electrically Small Metamaterial Inspired Monopole Antenna Using Double Negative Metamaterial and Ring Resonators

This paper proposes a new metamaterial inspired electrically small multi-band monopole antenna. The proposed antenna can operate at DCS 1800 in the lower band and covers two wireless local area network (WLAN) bands in the higher band. This paper describes the design and a detailed analysis of the electrically small antenna, where the compactness is achieved by the application of double negative metamaterial on a monopole antenna and multiband operation is achieved by the addition of two ring resonators. The ground structure is modified for giving proper impedance matching at lower bands. Moreover, an additional double negative structure of similar design is also incorporated to enhance its gain. A comparative study of the proposed antenna with other reported electrically small antennas is summarized and analyzed. A prototype of the proposed antenna is fabricated on a low cost substrate and experimentally validated.

Translocation of polyubiquitinated protein substrates by the hexameric Cdc48 ATPase

The hexameric Cdc48 ATPase (p97 or VCP in mammals) cooperates with its cofactor Ufd1/Npl4 to extract polyubiquitinated proteins from membranes or macromolecular complexes for degradation by the proteasome. Here, we clarify how the Cdc48 complex unfolds its substrates and translocates polypeptides with branchpoints. The Cdc48 complex recognizes primarily polyubiquitin chains rather than the attached substrate. Cdc48 and Ufd1/Npl4 cooperatively bind the polyubiquitin chain, resulting in the unfolding of one ubiquitin molecule (initiator). Next, the ATPase pulls on the initiator ubiquitin and moves all ubiquitin molecules linked to its C terminus through the central pore of the hexameric double ring, causing transient ubiquitin unfolding. When the ATPase reaches the isopeptide bond of the substrate, it can translocate and unfold both N- and C-terminal segments. Ubiquitins linked to the branchpoint of the initiator dissociate from Ufd1/Npl4 and move outside the central pore, resulting in the release of unfolded, polyubiquitinated substrate from Cdc48.