Multi-kilowatt single-mode ytterbium-doped large-core fiber laser

We have demonstrated a highly efficient cladding-pumped ytterbium-doped fiber laser, generating >2.1 kW of continuous-wave output power at 1.1 µm with 74% slope efficiency with respect to launched pump power. The beam quality factor (M2) was better than 1.2. The maximum output power was only limited by available pump power, showing no evidence of roll-over even at the highest output power. We present data on how the beam quality depends on the fiber parameter, based on our current and past fiber laser developments. We also discuss the ultimate power-capability of our fiber in terms of thermal management, Raman nonlinear scattering, and material damage, and estimate it to 10 k

Rancang Bangun Aplikasi Pendataan Potensi Desa / Kelurahan Berbasis Web

Setiap tahun mahasiswa Universitas SamRatulangi mengikuti mata kuliah “Kuliah Kerja Nyata” (KKN). Selama diterjunkan ke desa/kelurahan di kabupaten/kota dalam cakupan wilayah provinsi Sulawesi Utara, mahasiswa akan melakukan pendataan yang berhubungan dengan potensi desa/kelurahan yang ada sesuai lokasi penempatan masing-masing. Terkadang di beberapa desa/ kelurahan belum tersedia fasilitas akses internet sehingga proses pengisian data harus dilakukan secara manual dan dicetak lalu dikumpulkan kepada panitia pada saat program KKN selesai. Selanjutnya laporan potensi desa/kelurahan tersebut akan dikumpulkan di Lembaga Penelitian dan Pengabdian Masyarakat (LPPM) UNSRAT hal ini menyebabkan data yang telah terkumpul sangat sulit dianalisa karena belum terkomputerisasi. Penelitian ini bertujuan untuk merancang database potensi desa/kelurahan dan membangun sebuah aplikasi yang akan digunakan untuk melakukan pendataan potensi desa/kelurahan sehingga data-data yang ada dapat disatukan serta membantu pemerintah daerah dalam melakukan perencanaan pembangunan desa/kelurahan yang tepat sasaran dan berkesinambungan. Dalam penelitian ini aplikasi dibangun dengan menggunakan ​framework codeigniter secara portable yang ditempatkan dalam flashdisk sehingga aplikasi dapat bekerja baik secara daring maupun non daring. Pihak LPPM UNSRAT akan membagikan flashdisk berisi aplikasi pendataan potensi desa/kelurahan saat pembekalan KKN sesuai lokasi penempatan mahasiswa dimana satu flashdisk berlaku untuk satu desa/kelurahan. Selama berada di lokasi penempatan mahasiswa akan melakukan pengisian data potensi desa/kelurahan. Setelah data potensi desa/kelurahan selesai diinput maka flashdisk yang berisi aplikasi pendataan akan dikumpulkan kembali ke pihak LPPM UNSRAT. Selanjutnya Pihak LPPM UNSRAT melakukan penyatuan seluruh data-data potensi desa/ kelurahan dari seluruh flashdisk melalui aplikasi pendataan potensi desa/keluraha

Antiprädationsverhalten von Weißwangengänsen auf Kolguyev und Svalbard

Auch in den arktischen Brutgebieten sind Wildgänse und ihre Brut durch Fressfeinde wie den Eisfuchs (Alopex lagopus) oder die Eismöwe (Larus hyperboreus) gefährdet. In diesem Bericht wird am Beispiel von Weißwangengänsen (Branta leucopsis) das Verhalten der Vermeidung von Prädation auf Svalbard mit dem der auf Kolguyev brütenden Artgenossen untersucht. Die Unterschiede und Gemeinsamkeiten werden diskutiert.On the breeding grounds geese and their broods are threatened by predators like polar foxes (Alopex lagopus) or Glacous Gulls (Larus hyperboreus). In this review we compare antipredation behaviour of breeding and broad rearing Barnacle Geese (Branta leucopsis) on Svalbard and Kolguev. Similarities and differences are presented and discussed

Analisis dan Perancangan Sistem Interactive Voice Response (IVR) Berbasis Openvxi Menggunakan Asterisk pada Hotel Sahid Jaya

The purpose of this study is to provide a deep understanding of technology of IVR (Interactive Voice Recognition) in OpenVXI based network using Asterisk, that help Sahid Jaya hotel to streamline communication with the guests, improving service and employee effectiveness. The methodology used is analysis which is through surveys, observation and interviews with the company and the design method by designing system from the existing needs analysis. The results obtained from this research is Communication System based in IVR OpenVXI can be applied to existing VoIP network, without disrupting the existing network. Some existing services can be supported with this system USAge. Conclusions can be drawn is the use of IVR in the network using VoIP technology is the best solution to overcome the problems and needs of the hospitality which one of these is limited information guest cna get that can provided by non-operators and for support service improvement

Certification of an aircraft and airborne surveillance of fuel sulfur content in ships at the SECA border

In 2015 new rules from the IMO and legislation from EU (Sulfur directive) and the US requires ships to run with maximum fuel sulfur content (FSC) of 0.1 % m/m in northern European and North American waters. In order to promote a level playing field within the shipping sector, there is a need for measurement systems that can make effective compliance control and this is the main objective of the CompMon project, funded through the European CEF program (Connecting Europe Facility). As part of this project, a sensor system has been certified for ship surveillance measurements in a Piper Navajo aircraft and it has been demonstrated for airborne measurements of FSC in individual ships on the English Channel. The measurement system consists of an optical module which measures total emissions of SO2 and NO2 in g/s and a sniffer system by which FSC is retrieved from extractive measurements of SO2 and CO2. It can be used from fixed sites, patrol vessels and from aircraft. The advantage with airborne surveillance is the capability to check ships that are operating in the main shipping lanes, up to 200 nautical miles from shore. The precision of the estimated FSC from the sniffer system is 0.05 % m/m and hence at the 95 % confidence limit, ships above a FSC of 0.2 % m/m can be checked. The sniffer system also has a negative bias in the FSC of approx- imately 0.04 % m/m which is accounted for in the FSC calculations. The optical system has larger measurement uncertainties than the sniffer but it is intended mostly for guid- ance of other controls. As part of the CompMon project, a measurements campaign with the Navajo Piper aircraft was carried out at the SECA (Sulfur Emission Control Area) border in the English Channel at longitude 5 W. Six flight missions with duration of 4 to 5 hours were carried out from September 2 to 10, 2016, flying from Brest airport. In this manner it was possible to cover the longitude range 2o - 6o W. During the campaign, 114 ships were measured with the sniffer system, corresponding to 71 ships inside the SECA and 42 ships outside. The level of compli- ance inside the SECA was here 87 % and this is considerably lower than measurements carried out elsewhere within CompMon in other parts of the SECA (95-99 %). Two thirds of the non-complying vessels were leav- ing the SECA. With the optical system 110 individual ships were measured, 42 outside and 68 inside the SE- CA. The measurements show a similar pattern as the sniffer data but with a few false values. Nevertheless it is shown that both low and high FSC ships will be classified correctly with about 80-90 % probability with the optical system and this system is hence very promising as a tool to guide further compliance controls

Surveillance of Sulfur Emissions from Ships in Danish Waters

In 2015 new rules from the IMO and legislation from EU (Sulfur directive) requires ships to run with maximum fuel sulfur content (FSC) of 0.1 % m/m in northern European waters. In order to promote a level playing field within the shipping sector, there is a need for measurement systems that can make effective compliance control. This report describes the results from ship emission measurements on the waters surrounding Denmark from June 2015 to July 2017 on behalf of the Danish Environmental Protection Agency. The overall aim was to carry out operational surveillance of ships with respect to the EU sulfur directive and particularly the sulfur limits for marine fuel in the European Sulfur Emission Control Area (0.10 %), which entered into force on January 1st 2015, as well as to guide further port state control of ships at the destination harbors of the ships, both in Denmark and other ports. During the project the FSC of individual ships was estimated by perform- ing spot checks of exhaust plumes of individual ships. This was conducted by automatic gas sniffer measurements at the Great Belt Bridge and airborne surveillance measurements using sniffer and optical sensors. The data from the fixed system were transmitted in real time to a web database and alarms were triggered for high FSC ships in the form of emails. The report describes the technical systems and their performance and the general compliance levels of the measured ships. The measurement systems have been developed by Chalmers University of Technology through Swedish national funding and the EU project CompMon. The airborne dataset corresponds to approx. 900 individual ships, measured by sniffer or/and optical sensor over 245 flight hours. The optical sensor has low precision and is therefore used as a first alert system to identify ships running on high sulfur fuel. The precision of the airborne FSC meas- urements by the sniffer system is better and it is estimated as \ub1 0.05 % m/m (1σ) with a systematic bias of - 0.045 % m/m. Therefore only ships running with FSC of 0.2 % m/m or higher can be de- tected as non-compliant ships with good confidence limit (95 %) by the airborne sniffer system. The airborne measurements during 2015 and 2016 on Danish waters show that 94 % of the ships complied with the EU Sulphur directive, at the 95 % confidence limit. The compliance rate was lower, 92 %, during the 2nd half of 2016. In the period June 2015 to May 2017, 8426 sniffer measurements of individual ships were carried out at the Great Belt Bridge. However, there were technical problems in the first part of the project and the sniffer therefore had reduced sensitivity the first year and only high sulfur ships (> 1 % FSC) could be detected as non-complying vessels with appropriate statistical confidence. The precision in the estimated FSC by the fixed sniffer system is estimated as \ub1 0.04 % m/m (1σ) with a systematic bias of - 0.055 % m/m. Therefore only ships running with FSC of 0.18 % or higher can be detected as non-compliant ships with good confidence limit (95 %) by the fixed sniffer system. The data for the period June 2016 to October 2016 show a compliance rate of 94.6 % which increased to 97.4 % in the period January 2017 to May 2017. The compliance level during different time periods and platforms varied between 92-97 %. Here 1 - 2 % of the ships were in gross non-compliance with the EU sulfur directive with FSC values above 0.5 % m/m. There were differences over time, with the highest values in the summer of 2016. The compliance level was close to the values (95 %) measured by port state control authorities in Sweden and Denmark 2015 and 2016. When comparing ships measured by port state and the ones in this project it can be deduced that the efficiency of finding non-compliant vessels could be increased by at least a factor of 4, if the port state controls were guided by measurements. Most of the non-compliant ships (90 %) were measured high only once. But there were cases with individual ships and ship operators that were more abundant in the non-compliance statistics. The non- compliant ships that were seldom in the area around Denmark had higher emissions of SO2 than the non-compliant ones that operated their more frequently. On several occasions during this study we encountered ships equipped with scrubbers that were non-compliant with respect to the EU sulfur directive

Fixed remote surveillance of fuel sulfur content in ships from fixed sites in the Göteborg ship channel and Öresund bridge

In 2015 new rules from the IMO and legislation from EU (Sulfur directive) and the US requires ships to run with maximum fuel sulfur content (FSC) of 0.1 % m/m in northern European and North American waters. In order to promote a level playing field within the shipping sector, there is a need for measurement systems that can make effective compliance control and this is the main objective of the CompMon project, funded through the European CEF program (Connecting Europe Facility). As part of this project, an automatic sniffer sensor system has been applied in the Göteborg ship channel at the Älvsborg island during 3 years (2014- 2016) and at the Öresund Bridge during two months at the end of 2016. The typical distances from the ships here varied between 500 -1000 m. The sniffer system is based on several extractive instruments measuring concentrations of SO2 and CO2 and others species, such as NOx, in the ship emission plumes that drift over the measurement station. In addition to fixed stations, the system can also be used from mobile platforms such as harbor patrol vessels and aircraft. From the data above, together with information about the ships from AIS (Automatic Identification System) and wind data, the FSC is automatically calculated and the ship is identi- fied. This is done using software developed as part of this project (Single Emitter identification Tool).The measurement precision (1σ) of the sniffer system is approx. 0.04 % m/m for ships using a FSC of 0.1 % m/m. The sniffer system also has a negative bias in the measured FSC, varying between 0.04 % to 0.08 % m/m and this is accounted for when calculating the threshold for non-compliance. Based on the above, it is possible to identify ships with FSC above 0.18 % m/m with 95% confidence limit, if the bias is corrected for statistically. For the measurements at the Älvsborg island site in 2014 and 2015, the corresponding limit is higher, 0.29 % m/m, due to a measurement artifact that was eliminated in 2016. On board measurements in 2015 and 2016 by the Swedish port state control authority shows that most non-compliant ships had FSCs be- tween 0.1 % to 0.2 % m/m when controlled at berth and this is generally below the 95% confidence limit threshold of the sniffer. Therefore many non-compliant ships will not be detected when using the sniffer close to harbors and a more precise sensor is therefore preferred.The measurements at the Älvsborg island were carried out during a time period when the allowed FSC limit changed significantly. The data for 2014, corresponding to more than 4000 measurements of 500 individual ships, shows that 99 % of the ships were using compliant fuel below the FSC limit of 1 % m/m. In 2015 the FSC limit changed to 0.1 % m/m. The measurements in 2015 and 2016, corresponding to the same amount of ships as in 2014, showed that 91.5 % and 98 %, respectively, were using compliant fuel with respect to FSC. The lower compliance rate in 2015 compared to 2016 is potentially influenced by measurement artifacts that were later eliminated in 2016. At the Öresund Bridge. 58 ships were measured as part of the CompMon pro- ject. The measurements continued another month with support from the interreg project Envisum, with anoth- er 62 ships measured. The compliance level at the Öresund Bridge corresponds to 98 %. This is actually com- parable to the corresponding measurements elsewhere and at the Älvsborg island site during the same time period

The Burst Cluster: Dark Matter in a Cluster Merger Associated with the Short Gamma Ray Burst, GRB 050509B

We have identified a merging galaxy cluster with evidence of two distinct sub-clusters. The X-ray and optical data suggest that the subclusters are moving away from each other after closest approach. This cluster merger was discovered from observations of the well localized short-duration gamma-ray burst (GRB), GRB 050509B. The Swift/Burst Alert Telescope (BAT) source position is coincident with a cluster of galaxies ZwCl 1234.0+02916. The subsequent Swift/X-Ray Telescope (XRT) localization of the X-ray afterglow found the GRB coincident with 2MASX J12361286+2858580, a giant red elliptical galaxy in the cluster. Deep multi-epoch optical images were obtained to constrain the evolution of the GRB afterglow, including a 27480s exposure in the F814W band with Hubble Space Telescope Advanced Camera for Surveys (ACS), among the deepest imaging ever obtained towards a known galaxy cluster in a single passband. We perform a weak gravitational lensing analysis, including mapping the total mass distribution of the merger system. Combined with Chandra X-ray Observatory and Swift/XRT observations, we investigate the dynamical state of the merger to probe the nature of the dark matter component. Our weak gravitational lensing measurements reveal a separation of the X-ray centroid of the western subcluster from the center of the mass and galaxy light distributions, similar to that of the famous "Bullet cluster". We conclude that the "Burst cluster" is another candidate merger system for determining the nature of dark matter and for studying the environment of short GRBs. We discuss connections between the cluster dynamical state and/or matter composition and compact object mergers, the leading model for the origin of short GRBs. Finally, we present results from a weak lensing survey based on archival Very Large Telescope (VLT) images in the areas of 5 other short GRBs.Comment: 17 pages, 7 figures, accepted by Ap

Linear and nonlinear waveguides induced by optical vortex solitons

We study, numerically and analytically, linear and nonlinear waveguides induced by optical vortex solitons in a Kerr medium. Both fundamental and first-order guided modes are analyzed, as well as the cases of effectively defocusing and focusing nonlinearity.Comment: 3 pages, 3 figures, changed conten