Identification of Sediment Formation Based on Magnetic Content and Element Composition of Mud Volcano in Sangiran Sediment using VSM and X-Ray Fluorescence

Based on trace geological history and several studies, the Sangiran mud volcano provides insight into the geology and hydrology of the region, aquifer system in the basin, groundwater flow patterns and characteristics, rock lithology, hydrogeology condition, and saltwater trap mapping. Related to these conditions, studies were conducted on the magnetic content and composition of the major oxide compounds in the Sangiran sediments. Sample analysis was based on geochemical methods. The methods consist of frequency dependent magnetic susceptibility and vibrating sample magnetometer (VSM) analysis. Geochemical analyses using x-ray fluorescence (XRF) analysis have been conducted and various elemental grades have been determined. VSM results confirm that the magnetic content of Sangiran sediments is partly dominated by Fe (17.66 percent) contained in hematite (Fe2O3). At the same time, the samples of Sangiran sediment were enriched by Si, Fe, Al, Ca, Cl, Ti, and K according to XRF measurements. The samples exhibited the highest Si and Fe concentrations in samples T1 (Si is 29.48 percent and Fe is 13.66 percent) and T7 (Si is 24.95 percent and Fe is 12.01 percent). Meanwhile, in the T4 sample, the highest concentrations were Si and Ca, 23.45 percent and 13.45 percent, respectively. Retrieved from the magnetic susceptibility measurement, this paper confirm that Fe content is one of the components of volcanic ash in the Sangiran sediment.DOI: 10.17977/um024v8i12023p00

The United States COVID-19 Forecast Hub dataset

Academic researchers, government agencies, industry groups, and individuals have produced forecasts at an unprecedented scale during the COVID-19 pandemic. To leverage these forecasts, the United States Centers for Disease Control and Prevention (CDC) partnered with an academic research lab at the University of Massachusetts Amherst to create the US COVID-19 Forecast Hub. Launched in April 2020, the Forecast Hub is a dataset with point and probabilistic forecasts of incident cases, incident hospitalizations, incident deaths, and cumulative deaths due to COVID-19 at county, state, and national, levels in the United States. Included forecasts represent a variety of modeling approaches, data sources, and assumptions regarding the spread of COVID-19. The goal of this dataset is to establish a standardized and comparable set of short-term forecasts from modeling teams. These data can be used to develop ensemble models, communicate forecasts to the public, create visualizations, compare models, and inform policies regarding COVID-19 mitigation. These open-source data are available via download from GitHub, through an online API, and through R packages

Tek molekül tespiti için FREkans MOdüleli Raman Saçılması (FREMORS)

Bu projede amaç “tek molekül tespiti için FREkans MOdüleli Raman Saçılması (FREMORS)” aygıtı üretmektir. Bu aygıtın Raman spektroskopisine dayalı olarak tek molekül tespitine imkan vermesi, yüzey arttırımlı Raman spektroskopisi (SERS) gibi plazmonik arttırım ile yapılacaktır. SERS yöntemiyle elde edilen sinyalin rastlantısal olarak moleküllerin sıcak noktalara gelmesi olasılığına bağlı kalmasından farklı olarak, bahsedilen aygıt ile iyi belirlenmiş nanoboyutta bir bölgeden tek molekül bilgisi alınabilecektir. FREMORS sensor aygıtı; yiyeceklerdeki çok az miktarlarda kontaminantı, hassas bölgelerdeki patlayıcıyı, kan örneklerindeki uyuşturucuları, proteinleri ve antikorları güncel aygıtların erişemeyeceği hassaslıkta tespit etmek için kullanılabilir. Bu aygıtın en önemli özellikleri; benzersiz hassaslık, alınan sonuçtaki kesinlik ve kolay üretim olacaktır

Monolayer Assembly of MultiSpiked Gold Nanoparticles for Surface-Enhanced Raman Spectroscopy-Based Trace Detection of Dyes and Explosives

For sensitive and reproducible surface-enhanced Raman scattering (SERS)-based trace detection, a SERS platform with high concentration of homogeneously distributed hotspots is needed. Herein, we report a facile monolayer assembly of multispiked gold nanoparticles (MSGNPs) of various sizes over a large area. The assembly was achieved simply by tuning the concentration of MSGNPs in a suspension and subsequently drying it on a substrate under ambient conditions. A monolayer assembly for MSGNP sizes ranging from 150 to 640 nm has been demonstrated. The MSGNP assembly showed excellent sensitivity and uniformity of SERS-based trace detection, owing to the presence of high concentration of uniformly distributed interparticle and intraparticle hotspots. In particular, detection of 10 fM of a toxic dye, crystal violet, has been demonstrated. Moreover, ammonium nitrate, which is a commonly used material for homemade explosives, was detected at 1 mu M level. The MSGNP-based SERS platforms have great potential for applications in sensitive and reliable toxin and explosive detection

Düzenli nano yapılarla donatılmış Raman artırım arayüzleri üretilmesi ve artırım kanallarının analizi

Bu projede amaç yüksek artırımlı yüzey artırımlı Raman saçılım (SERS) arayüzleri üretilmesi ve kimyasal SERS artırım mekanizmalarının ayırt edilmeye çalışılmasıdır. Üretim tekniği olarak hassas nano boşluklu geniş alan nano yapı üretimine uygun grubumuzca bir süredir geliştirilmekte olan deşik maske litografisi kullanılacaktır. Güçlü çınlayan nano boşluklu yapılarla donatılmış Raman artırım arayüzleri üretilecektir. Üretilen yüksek artırımlı SERS arayüzleri atomik katman biriktirme yöntemi kullanılarak farklı kimyasal özellikteki nanometre altı dielektirik malzemeler ile kaplanacak böylelikle Raman artırımının sebeplerinden biri olan kimyasal artırım özellikleri değiştirilecektir. Üretilen örnekler üzerinden toplanan verilerdeki Raman şiddeti farkı incelenerek elektro manyetik Raman artırım kanalı kadar iyi anlaşılamayan kimyasal Raman artırım kanalının etkileri deneysel olarak ortaya konulacaktır

Femtosaniye kızılötesi lazerle silisyum pul içi gömülü kırınım yapılarının 5 mikrometre altı çözünürlükle doğrudan yazılması

Projenin amacı, bizim keşfettiğimiz ve dünyada ilk kez silisyumun (Si) yüzey-altında ve 3 boyutlu olarak işlenmesine olanak sağlayan bir tekniği geliştirerek gömülü kırınımsal optik elemanların üretimi için sisteme yüksek çözünürlük kazandırmaktır. Bu teknikte kristal Si’un içinde kristal yapısı bozulmuş Si yapılar, Si’un geçirgen olduğu 1,5 μm dalgaboyunda çalışan kısa (femtosaniye) lazer atımlarının Si içinde doğrusal olmayan bir geri besleme mekanizmasıyla kendiliğinden oluşmaktadır. Yapıların üretimi 3 boyutlu olarak motorize konumlandırıcılar aracılığıyla kontrol edilmektedir. Silisyum içine yazılan yapılar seçici kimyasal aşındırmayla çıkarılarak kalan şekillendirilmiş yüzeyler kullanılarak fotonik aygıtların dalgaboyu çalışma aralığı görünür bölgeyi kapsayacak şekilde geliştirilebilmektedir. Ön çalışmalarımız sonucunda, yonga içerisinde mercek ve hologramlar oluşturulabilmiş ve 1,064 μm dalgaboyunda deneysel olarak test edilmiştir. Gerçekleştirdiğimiz çalışmalarda kendinden limitli bir etkileşim mekanizması nedeniyle silisyum içine yazılabilen yapıların piksel boyutları en küçük 10-15 mikrometre arasında kalmaktadır. Projenin somut hedefi bu yeni lazer-malzeme işleme rejimi ile göstermiş olduğumuz yazma işleminin çözünürlüğünü artıracak mekanizmalar geliştirmek, bu sayede 5 mikrometre altı çözünürlükte pikselleri doğrudan lazerle silisyum içine yazmak ve seçici aşındırmayla bu yüksek çözünürlükte yapıları ortaya çıkarmaktır

Facile preparation of nanoparticle based SERS substrates for trace molecule detection

In this work, we demonstrate that a polished Si wafer surface can be converted to possess strong surface-enhanced Raman scattering (SERS) activity by spray coating of polyol synthesized colloidal silver nanoparticles (AgNPs) at as low as 1% surface coverage. The SERS activity assays of substrate surfaces prepared with different production procedures (spray and spin coating) at different surface coverages are realized using population statistics. The resulting Raman enhancement factors (EFs) are discussed with the help of distance-dependent electromagnetic simulations for single particles and dimers. Statistics on the SERS effect and the corresponding EF calculations show that polyol synthesized AgNPs exhibit extremely strong SERS activity with EFs up to 10(8)at as low as 1% surface coverage. We discuss in this work that this is possible due to the distinct properties of polyol synthesized AgNPs such as atomically flat surfaces, sharp edges and corners naturally occurring in this synthesis method, which favor strong plasmonic activity. The method can be generalized to convert virtually any surface into a SERS substrate

Plasmonic light-management interfaces by polyol-synthesized silver nanoparticles for industrial scale silicon solar cells

© 2020 American Chemical Society. All rights reserved.Plasmonic interfaces are used as an alternative and highly effective light management technique for solar cells. Topdown approaches produce well-ordered and carefully designed plasmonic structures for tailor-made light management; however, they are costly, and their fabrication is time-consuming. Thus, their utilization for industrial-scale solar cells is not trivial. It has been shown that dewetting is a cost- and time-effective bottom-up approach for the fabrication of plasmonic interfaces, yet it lacks precise control of the surface coverage for optimum light management. Therefore, new strategies are actively sought. In this work, the spray coating technique is used to deposit plasmonic interfaces with polyol synthesized silver bipyramidal nanocubes onto industrial-scale monocrystalline silicon solar cells. Through a systematic study, the effect of surface coverage on cell performance is investigated, as it is essential to utilize the interface in well-controlled amounts for optimal light management. A relative increase in the photovoltaic conversion efficiency of 3.5-6.4% upon creating localized surface plasmon resonance-based plasmonic interfaces is demonstrated

Synthesis of tin oxide-coated gold nanostars and evaluation of their surface-enhanced Raman scattering activities

Tin oxide-coated gold nanostar hybrid nanostructures are prepared by first synthesizing gold nanostars (ca. 400nm), then introducing Na2SnO3 precursor followed by its hydrolysis and formation of a tin oxide layer on nanoparticle surface. The synthesized hybrid structures have been characterized by combination of UV-Vis spectroscopy, transmission electron microscope (TEM), energy-dispersive X-ray studies, scanning electron microscope (SEM), X-Ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. The TEM and SEM analyses showed that gold nanostars have a coating with an approximate thickness of 15nm. The tin (IV) oxide coating on the gold nanostars was identified by XRD and XPS analyses and confirmed by FTIR spectroscopy. Surface-enhanced Raman scattering (SERS) spectroscopy was performed on tin oxide-coated and uncoated gold nanostars with crystal violet as a probe molecule. The SERS studies revealed field enhancement properties of Au nanostars, thus their strong SERS activity remained after tin oxide coating