scholarly journals Development and characterization of a mobile γ spectrometer and its field deployment for in situ radioactivity measurements

2021 ◽  
Vol 7 (2) ◽  
pp. 157-164
Author(s):  
T. J. Mertzimekis ◽  
C. Andrikopoulos ◽  
C. Fakiola ◽  
A. Kotsovolou ◽  
D. Lampridou ◽  
...  
Keyword(s):  
Point Sources ◽  
Chernobyl Fallout ◽  
Test Operation ◽  
Custom Made ◽  
Absolute Efficiency ◽  
Field Deployment ◽  
Γ Spectrometer ◽  
Trace Concentrations ◽  
The University

A mobile γ–ray spectrometer (AMESOS) has been developed using a 3”×3” NaI(Tl) detector, a custom–made mounting holder, and portable electronics to perform in situ measurements of radioactivity. The spectrometer was calibrated using standard point sources and its absolute efficiency was determined. As a field test operation, AMESOS was deployed on the premises of the University of Athens Zografou campus focusing on estimating the NORM levels. Data were analyzed and used to create radiological maps for the metropolitan UoA campus for the first time. Besides natural radioactivity levels, trace concentrations of 137Cs were also detected, attributed to the Chernobyl fallout in Greece. An overall steady performance of the spectrometer was observed throughout the field operation. AMESOS is ready to be deployed for in situ studies of environmental radioactivity and radwaste management.

Paleopathological study of the Egyptian mummies collected in Italy: the Anubis project

1970 ◽  
Vol 80 (1) ◽  
Author(s):  
Rosalba Ciranni ◽  
Donata Pangoli ◽  
Valentina Giuffra ◽  
DAvide Caramella ◽  
Edda Bresciani ◽  
...  
Keyword(s):  
X Rays ◽  
Axial Tomography ◽  
Technical Problems ◽  
Histological Studies ◽  
Computed Axial Tomography ◽  
The University ◽  
First Time

Eighty-five Egyptian mummies belonging to different dynastic periods and collected in a number of Italian museums, have been censed and submitted for paleopathological research. In most cases the presence of bandages required the application of X- rays and computed axial tomography (CAT). Fifty-two mummies have been studied in situ with Xrays; twelve with CAT scanning. Technical problems kept us from investigating eleven of the censed mummies. In a few cases it was possible to perform autopsies, endoscopy, or histological studies. The mummies submitted for X- rays were divided into two groups: The first group thirty-six mummies studied by the team of Paleopathology-Egyptology of the University of Pisa were studied for the first time. The second group was composed of twenty-six mummies studied elsewhere in Italy. Those results also have been included in the Anubi Project database.

scholarly journals A Leaf Point Documents Hunting with Spears in the Middle Paleolithic at Hohle Fels, Germany

2021 ◽  
Vol 2021 (30) ◽  
Author(s):  
Veerle Rots ◽  
Justin Coppe ◽  
Nicholas Conard
Keyword(s):  
Life History ◽  
Evolutionary Development ◽  
Functional Study ◽  
Middle Paleolithic ◽  
Projectile Technology ◽  
Excellent Preservation ◽  
The Rich ◽  
Pointed End ◽  
The University

During the 2020 season at Hohle Fels Cave in the Ach Valley of southwestern Germany the excavation team from the University of Tübingen recovered a bifacial leaf point in archaeological horizon (AH) X. This horizon is the fifth deepest of the Middle Paleolithic horizons at the site and is located roughly 120 cm beneath the base of the rich Aurignacian layers of the cave. The new leaf point, or Blattspitze in German, is the first artifact of its kind found in situ in the Swabian caves since Gustav Riek’s excavation at Haldenstein Cave near the source of the Lone River recovered two leaf points in excellent preservation in 1936. The new find allowed our team to conduct the first techno-functional study of a freshly recovered leaf point from the European Middle Paleolithic. This study demonstrates that the leaf point was hafted at the less pointy end of the artifact. The leaf point bears clear damage to the pointed end of the artifact that occurred during a hunting episode. A Neanderthal knapper further damaged the tool during an attempt to resharpen and rejuvenate the tool. This damage was likely the reason the knapper discarded the leaf point at Hohle Fels. This result and a re-examination of the two leaf points from Haldenstein Cave indicate that late Neanderthals used Blattspitzen for hunting large game. The current results do not explicitly prove that spears with hafted leaf points were always thrown or used as thrusting spears, and one can easily imagine scenarios in which a weapon of this kind could be used in both ways. Ideally, the ongoing excavation at Hohle Fels will recover more leaf points, which will give us the opportunity to document the technological variability of this kind of tool with regard to their manufacture, function and life history. We also view the current research at Hohle Fels as an excellent opportunity to gain a better and more strongly contextualized understanding of the technological system linking lithic, botanical and osseous technologies during this phase of the Middle Paleolithic. This paper also considers the place that hafted leaf points have within the broader evolutionary development of hunting and projectile technology.

scholarly journals Controlled sample environment for studying solid–gas interactions by in situ powder X-ray diffraction

2021 ◽  
Vol 54 (1) ◽  
pp. 371-375
Author(s):  
Paul Monceyron Røren ◽  
Kristoffer W. B. Hunvik ◽  
Vegard Josvanger ◽  
Ole Tore Buseth ◽  
Jon Otto Fossum
Keyword(s):  
Applied Pressure ◽  
Copper Plate ◽  
Temperature Control System ◽  
X Ray Diffraction ◽  
X Ray ◽  
Custom Made ◽  
Quartz Capillary ◽  
Gas Interactions ◽  
And Control

A sample cell for powder X-ray diffraction studies with in situ applied pressure and control of temperature is demonstrated. The cell is based on a previously reported design and consists of a glass or quartz capillary glued into a Swagelok weld gland; this configuration can hold up to 100 bar (1 bar = 100 kPa). The cell is placed in contact with a copper plate for control of temperature between −30 and 200°C. This is achieved by Peltier elements, heat cartridges and a refrigerated circulating bath. This work mainly focuses on the temperature control system. Commissioning tests were performed in a custom-made small/wide-angle X-ray diffractometer at the Norwegian University of Science and Technology. The system is easily portable to synchrotron facilities.

scholarly journals The Athens Mobile γ-Spectrometry System (AMESOS)

2019 ◽  
Vol 23 ◽  
pp. 150
Author(s):  
A. Karailias ◽  
V. Lagaki ◽  
C. Katsiva ◽  
A. Kanellakopoulos ◽  
T. J. Mertzimekis ◽  
...  
Keyword(s):  
Absorbed Dose ◽  
In Situ Measurements ◽  
Harsh Environments ◽  
The Public ◽  
Dose Rates ◽  
Field Operation ◽  
Standard Calibration ◽  
Γ Spectrometry ◽  
The University

We report on a new mobile γ-spectrometry system (AMESOS) developed at the University of Athens. The system aims at carrying out in situ measurements to study distributions of NORM and TENORM at harsh environments or where sampling is difficult. AMESOS has been characterized by using standard calibration sources and minerals of known, independently determined, U and Th concentrations. Simulations of the system have been performed with MCNP and Geant4. As a proof of good field operation, AMESOS was deployed in a series of measurements at Mt. Kithaeron, near Athens, extending earlier data and estimating absorbed dose rates that concern the public.

Effect of 10% and 15% Carbamide Peroxide on Fracture Toughness of Human Dentin In Situ

2013 ◽  
Vol 38 (2) ◽  
pp. 142-150 ◽  
Author(s):  
LE Tam ◽  
P Bahrami ◽  
O Oguienko ◽  
H Limeback
Keyword(s):  
Fracture Toughness ◽  
Placebo Group ◽  
Color Change ◽  
Carbamide Peroxide ◽  
Tooth Sensitivity ◽  
Custom Made ◽  
Dental Hard Tissues ◽  
Significant Difference

SUMMARY Purpose Although damage to the structural integrity of the tooth is not usually considered a significant problem associated with tooth bleaching, there have been some reported negative effects of bleaching on dental hard tissues in vitro. More studies are needed to determine whether the observed in vitro effects have practical clinical implications regarding tooth structural durability. Objectives This in situ study evaluated the effect of 10% and 15% carbamide peroxide (CP) dental bleach, applied using conventional whitening trays by participants at home, on the fracture toughness of dentin. Methods Ninety-one adult volunteers were recruited (n ≈ 30/group). Compact fracture toughness specimens (approximately 4.5 × 4.6 × 1.7 mm) were prepared from the coronal dentin of recently extracted human molars and gamma-radiated. One specimen was fitted into a prepared slot, adjacent to a maxillary premolar, within a custom-made bleaching tray that was made for each adult participant. The participants were instructed to wear the tray containing the dentin specimen with placebo, 10% CP, or 15% CP treatment gel overnight for 14 nights and to store it in artificial saliva when not in use. Pre-bleach and post-bleach tooth color and tooth sensitivity were also evaluated using ranked shade tab values and visual analogue scales (VASs), respectively. Within 24–48 hours after the last bleach session, the dentin specimens were tested for fracture toughness using tensile loading at 10 mm/min. Analysis of variance, Kruskal-Wallis, χ2, Tukey's, and Mann-Whitney U tests were used for statistical analysis. The level of significance was set at p<0.05 for all tests, except for the Mann-Whitney U tests, which used a Bonferroni correction for post hoc analyses of the nonparametric data (p<0.017). Results The placebo, 10% CP, and 15% CP groups contained 30, 31, and 30 participants, respectively. Mean fracture toughness (+ standard deviation) for the placebo, 10% CP, and 15% CP groups were 2.3 ± 0.9, 2.2 ± 0.7, and 2.0 ± 0.5 MPa*m1/2 respectively. There were no significant differences in mean fracture toughness results among the groups (p=0.241). The tooth sensitivity VAS scores indicated a significantly greater incidence (p=0.000) and degree of tooth sensitivity (p=0.049 for VAS change and p=0.003 for max VAS) in the bleach groups than in the placebo group. The color change results showed generally greater color change in the bleach groups than in the placebo group (p=0.008 for shade guide determination and p=0.000 for colorimeter determination). Conclusions There were no significant differences in in situ dentin fracture toughness results among the groups. The results of this study provide some reassurance that dentin is not overtly weakened by the bleaching protocol used in this study. However, the lack of a statistically significant difference cannot be used to state that there is no effect of bleach on dentin fracture toughness.

scholarly journals Validation of aerosol backscatter profiles from Raman lidar and ceilometer using balloon-borne measurements

2021 ◽  
Vol 21 (3) ◽  
pp. 2267-2285
Author(s):  
Simone Brunamonti ◽  
Giovanni Martucci ◽  
Gonzague Romanens ◽  
Yann Poltera ◽  
Frank G. Wienhold ◽  
...  
Keyword(s):  
Remote Sensing ◽  
In Situ Measurements ◽  
Aerosol Size Distribution ◽  
Spatial And Temporal Variability ◽  
Raman Lidar ◽  
Backscatter Coefficient ◽  
Custom Made ◽  
Aerosol Backscatter ◽  
Good Agreement

Abstract. Remote-sensing measurements by light detection and ranging (lidar) instruments are fundamental for the monitoring of altitude-resolved aerosol optical properties. Here we validate vertical profiles of aerosol backscatter coefficient (βaer) measured by two independent lidar systems using co-located balloon-borne measurements performed by Compact Optical Backscatter Aerosol Detector (COBALD) sondes. COBALD provides high-precision in situ measurements of βaer at two wavelengths (455 and 940 nm). The two analyzed lidar systems are the research Raman Lidar for Meteorological Observations (RALMO) and the commercial CHM15K ceilometer (Lufft, Germany). We consider in total 17 RALMO and 31 CHM15K profiles, co-located with simultaneous COBALD soundings performed throughout the years 2014–2019 at the MeteoSwiss observatory of Payerne (Switzerland). The RALMO (355 nm) and CHM15K (1064 nm) measurements are converted to 455 and 940 nm, respectively, using the Ångström exponent profiles retrieved from COBALD data. To account for the different receiver field-of-view (FOV) angles between the two lidars (0.01–0.02∘) and COBALD (6∘), we derive a custom-made correction using Mie-theory scattering simulations. Our analysis shows that both lidar instruments achieve on average a good agreement with COBALD measurements in the boundary layer and free troposphere, up to 6 km altitude. For medium-high-aerosol-content measurements at altitudes below 3 km, the mean ± standard deviation difference in βaer calculated from all considered soundings is −2 % ± 37 % (−0.018 ± 0.237 Mm−1 sr−1 at 455 nm) for RALMO−COBALD and +5 % ± 43 % (+0.009 ± 0.185 Mm−1 sr−1 at 940 mm) for CHM15K−COBALD. Above 3 km altitude, absolute deviations generally decrease, while relative deviations increase due to the prevalence of air masses with low aerosol content. Uncertainties related to the FOV correction and spatial- and temporal-variability effects (associated with the balloon's drift with altitude and different integration times) contribute to the large standard deviations observed at low altitudes. The lack of information on the aerosol size distribution and the high atmospheric variability prevent an accurate quantification of these effects. Nevertheless, the excellent agreement observed in individual profiles, including fine and complex structures in the βaer vertical distribution, shows that under optimal conditions, the discrepancies with the in situ measurements are typically comparable to the estimated statistical uncertainties in the remote-sensing measurements. Therefore, we conclude that βaer profiles measured by the RALMO and CHM15K lidar systems are in good agreement with in situ measurements by COBALD sondes up to 6 km altitude.

Functional Group Protection

2013 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Secondary Amines ◽  
Primary Amines ◽  
Silyl Ether ◽  
Southern Illinois ◽  
Convenient Procedure ◽  
North Eastern ◽  
National University ◽  
Facile Preparation ◽  
The University

Bekington Myrboh of North-Eastern Hill University reported (Tetrahedron Lett. 2010, 51, 2862) a convenient procedure for the oxidative removal of a 1,3-oxathiolane 1 or a 1,3-dithiolane. Sang-Gyeong Lee and Yong-Jin Yoon of Gyeongsang National University developed (J. Org. Chem. 2010, 75, 484) the pyridazin-3(2H )-one 4 for the microwave-mediated deprotection of an oxime 3. Dario M. Bassani of Université Bordeaux 1 and John S. Snaith of the University of Birmingham devised (J. Org. Chem. 2010, 75, 4648) a procedure for the facile preparation of esters such as 6. Brief photolysis (350 nm) returned the parent carboxylic acid 7. Craig M. Williams of the University of Queensland prepared (Tetrahedron Lett. 2010, 51, 1158) the trithioorthoester 8 by iterative opening of epichlorohydrin. He found that the keto ester 9 could be efficiently released by Hg-mediated hydrolysis. Masatoshi Mihara of the Osaka Municipal Technical Research Institute established (Synlett 2010, 253) that even very congested alcohols such as 10 could be acetylated by acetic anhydride containing a trace of FeCl3. Colleen N. Scott, now at Southern Illinois University, developed (J. Org. Chem. 2010, 75, 253) a convenient procedure for the preparation of the hydridosilane 13, which on Mn catalysis added the alcohol 12 to make the unsymmetrical bisalkoxysilane 14. Sabine Berteina-Raboin of the Université d’Orléans found (Tetrahedron Lett. 2010, 51, 2115) that NaBH4 in EtOH cleanly removed the chloroacetates from 15. Both other esters and silyl ethers were stable under these conditions. Ram S. Mohan of Illinois Wesleyan University established (Tetrahedron Lett. 2010, 51, 1056) that Fe(III) tosylate in methanol selectively removed the alkyl silyl ether from 17 without affecting the aryl silyl ether. Alakananda Hajra and Adinath Majee of Visva-Bharati University effected (Tetrahedron Lett. 2010, 51, 2896) formylation of an amine 19 by heating with commercial 85% formic acid as the solvent in a sealed tube at 80°C. Although both primary and secondary amines could be effi ciently formylated, the primary amines were much more reactive. Doo Ok Jang of Yonsei University found (Tetrahedron Lett. 2010, 51, 683) that the conveniently handled CF3CCO2H (the acid chloride is a gas) could be activated in situ to selectively convert 22 into 24.

In-Situ Oxidative Degradation of Emerging Contaminants in Soil and Groundwater Using a New Class of Stabilized MnO2 Nanoparticles

2016 ◽  
pp. 112-136
Author(s):  
Bing Han ◽  
Wen Liu ◽  
Dongye Zhao
Keyword(s):  
Organic Contaminants ◽  
Emerging Contaminants ◽  
Low Cost ◽  
Oxidative Degradation ◽  
In Situ Remediation ◽  
New Class ◽  
Mno2 Nanoparticles ◽  
In Situ Degradation ◽  
Trace Concentrations

Emerging Organic Contaminants (EOCs) such as steroidal estrogen hormones are of growing concern in recent years, as trace concentrations of these hormones can cause adverse effects on the environmental and human health. While these hormones have been widely detected in soil and groundwater, effective technology has been lacking for in-situ degradation of these contaminants. This chapter illustrates a new class of stabilized MnO2 nanoparticles and a new in-situ technology for oxidative degradation of EOCs in soil and groundwater. The stabilized nanoparticles were prepared using a low-cost, food-grade Carboxymethyl Cellulose (CMC) as a stabilizer. The nanoparticles were then characterized and tested for their effectiveness for degradation of both aqueous and soil-sorbed E2 (17ß-estradiol). Column tests confirmed the effectiveness of the nanoparticles for in-situ remediation of soil sorbed E2. The nanoparticle treatment decreased both water leachable and soil-sorbed E2, offering a useful alternative for in-situ remediation of EOCs in the subsurface.

C–N Ring Construction: The Waser Synthesis of Jerantinine E

2017 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Ni Catalyst ◽  
University Of Alberta ◽  
Princeton University ◽  
In Situ Preparation ◽  
National University ◽  
The University ◽  
École Polytechnique ◽  
Pais Vasco ◽  
Multicomponent Coupling

James A. Bull of Imperial College London prepared (J. Org. Chem. 2013, 78, 6632) the aziridine 2 with high diastereocontrol by adding the anion of diiodomethane to the imine 1. Karl Anker Jørgensen of Aarhus University observed (Chem. Commun. 2013, 49, 6382) high ee in the distal aziridination of 3 to give 4. Benito Alcaide of the Universidad Complutense de Madrid and Pedro Almendros of ICOQ- CSIC Madrid reduced (Adv. Synth. Catal. 2013, 355, 2089) the β-lactam 5 to the azetidine 6. Hiroaki Sasai of Osaka University added (Org. Lett. 2013, 15, 4142) the allenoate 8 to the imine 7, delivering the azetidine 9 in high ee. Tamio Hayashi of Kyoto University, the National University of Singapore, and A*STAR devised (J. Am. Chem. Soc. 2013, 135, 10990) a Pd catalyst for the enanti­oselective addition of the areneboronic acid 11 to the pyrroline 10 to give 12. Ryan A. Brawn of Pfizer (Org. Lett. 2013, 15, 3424) reported related results. Nicolai Cramer of the Ecole Polytechnique Fédérale de Lausanne developed (J. Am. Chem. Soc. 2013, 135, 11772) a Ni catalyst for the cyclization of the formamide 13 to the lactam 14. Andrew D. Smith of the University of St. Andrews used (Org. Lett. 2013, 15, 3472) an organocatalyst to cyclize 15 to 16. Jose L. Vicario of the Universidad del Pais Vasco effected (Synthesis 2013, 45, 2669) the multicomponent coupling of 17, 18, and 19, mediated by an organocatalyst, to construct 20 in high ee. André Beauchemin of the University of Ottawa explored (J. Org. Chem. 2013, 78, 12735) the thermal cyclization of ω-alkenyl hydroxyl amines such as 21. Abigail G. Doyle of Princeton University developed (Angew. Chem. Int. Ed. 2013, 52, 9153) a Ni catalyst for the enantioselective addition of aryl zinc bromides such as 24 to the pro­chiral 23, to give 25 in high ee. Dennis G. Hall of the University of Alberta developed (Angew. Chem. Int. Ed. 2013, 52, 8069) an in situ preparation of the allyl boronate 26 in high ee. Addition to the aldehyde 27 proceeded with high diasteroselectivity.

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