We have compared three different methods of treating symptomatic non-traumatic tears of the supraspinatus tendon in patients above 55 years of age. A total of 180 shoulders (173 patients) with ...supraspinatus tendon tears were randomly allocated into one of three groups (each of 60 shoulders); physiotherapy (group 1), acromioplasty and physiotherapy (group 2) and rotator cuff repair, acromioplasty and physiotherapy (group 3). The Constant score was assessed and followed up by an independent observer pre-operatively and at three, six and twelve months after the intervention. Of these, 167 shoulders were available for assessment at one year (follow-up rate of 92.8%). There were 55 shoulders in group 1 (24 in males and 31 in females, mean age 65 years (55 to 79)), 57 in group 2 (29 male and 28 female, mean age 65 years (55 to 79)) and 55 shoulders in group 3 (26 male and 29 female, mean age 65 years (55 to 81)). There were no between-group differences in the Constant score at final follow-up: 74.1 (sd 14.2), 77.2 (sd 13.0) and 77.9 (sd 12.1) in groups 1, 2 and 3, respectively (p = 0.34). The mean change in the Constant score was 17.0, 17.5, and 19.8, respectively (p = 0.34). These results suggest that at one-year follow-up, operative treatment is no better than conservative treatment with regard to non-traumatic supraspinatus tears, and that conservative treatment should be considered as the primary method of treatment for this condition.
Abstract
Cast structures must be allowed to dry sufficiently before they can be covered with impermeable coatings. During a commissioned study on the drying rate of calcium sulphate screed cast ...floor, it was observed that the measured relative humidity of the structure increased significantly after a vinyl flooring was glued to the surface of the structure. The cause for the phenomenon could not be determined based on the carried-out test arrangements. Therefore, a follow-up study with identical test structures was conducted to isolate the cause of the increase in measured relative humidity after coating. Tests confirmed that the effect was caused by the water contained in the adhesive. The adhesive was initially dosed by applying it with a trowel with specified notching as instructed. In the follow-up study, weighing the applied amount of adhesive revealed that the instructed amount was exceeded significantly. Due to the shape of the material’s equilibrium moisture content curve, even a small increase in moisture content significantly increases the structure’s relative humidity. Therefore, dosing instructions of applied adhesive must be followed precisely, as overdosing can potentially lead to moisture damages in related structures.
Abstract
The material properties of a brick masonry are important when modelling or comparing different veneers. The effect of mortar joint, however, is somewhat an unknown variable. In this study, ...two different firing batches of a hollow burnt-clay brick product were tested for thermal conductivity, water vapor permeability, water absorption coefficient and capillary moisture content. Brick and mortar materials were tested both exclusively and as masonry specimens. The effect of brick-mortar interface was within margin of error for the first brick batch with slightly lower density, while batch two water vapor permeability, water absorption coefficient and capillary moisture content were noticeably affected. The effect of brick-mortar interface seems to be dependent on brick properties. The differences in hygric properties between brick batches were large, but below 100 %. Accounting for mortar using area weighted properties can improve modelling accuracy, but other factors such as workmanship, degradation and brick batch differences are likely more important.
As a result of the foreseen increase in the luminosity of the Large Hadron Collider, the discrimination between the collision products and possible magnet quench-provoking beam losses of the primary ...proton beams is becoming more critical for safe accelerator operation. We report the results of ongoing research efforts targeting the upgrading of the monitoring system by exploiting Beam Loss Monitor detectors based on semiconductors located as close as possible to the superconducting coils of the triplet magnets. In practice, this means that the detectors will have to be immersed in superfluid helium inside the cold mass and operate at 1.9K. Additionally, the monitoring system is expected to survive 20 years of LHC operation, resulting in an estimated radiation fluence of 1×1016 proton/cm2, which corresponds to a dose of about 2MGy. In this study, we monitored the signal degradation during the in situ irradiation when silicon and single-crystal diamond detectors were situated in the liquid/superfluid helium and the dependences of the collected charge on fluence and bias voltage were obtained. It is shown that diamond and silicon detectors can operate at 1.9K after 1×1016p/cm2 irradiation required for application as BLMs, while the rate of the signal degradation was larger in silicon detectors than in the diamond ones. For Si detectors this rate was controlled mainly by the operational mode, being larger at forward bias voltage.
•Silicon and diamond detectors are proposed for beam loss monitoring at LHC.•The first in situ radiation test of Si and diamond detectors at 1.9K is described.•Both diamond and silicon detectors survived after 1×1016p/cm2 irradiation at 1.9K.•The rate of Si detectors degradation depends on bias polarity and is larger at Vforw.•Sensitivity of Si detectors irradiated to 1×1016p/cm2 is independent on resistivity.
Detectors manufactured on p-type silicon material are known to have significant advantages in very harsh radiation environment over n-type detectors, traditionally used in High Energy Physics ...experiments for particle tracking. In p-type (n+ segmentation on p substrate) position-sensitive strip detectors, however, the fixed oxide charge in the silicon dioxide is positive and, thus, causes electron accumulation at the Si/SiO2 interface. As a result, unless appropriate interstrip isolation is applied, the n-type strips are short-circuited. Widely adopted methods to terminate surface electron accumulation are segmented p-stop or p-spray field implantations. A different approach to overcome the near-surface electron accumulation at the interface of silicon dioxide and p-type silicon is to deposit a thin film field insulator with negative oxide charge. We have processed silicon strip detectors on p-type Magnetic Czochralski silicon (MCz-Si) substrates with aluminum oxide (Al2O3) thin film insulator, grown with Atomic Layer Deposition (ALD) method. The electrical characterization by current–voltage and capacitance−voltage measurement shows reliable performance of the aluminum oxide. The final proof of concept was obtained at the test beam with 200GeV/c muons. For the non-irradiated detector the charge collection efficiency (CCE) was nearly 100% with a signal-to-noise ratio (S/N) of about 40, whereas for the 2×1015neq/cm2 proton irradiated detector the CCE was 35%, when the sensor was biased at 500V. These results are comparable with the results from p-type detectors with the p-spray and p-stop interstrip isolation techniques. In addition, interestingly, when the aluminum oxide was irradiated with Co-60 gamma-rays, an accumulation of negative fixed oxide charge in the oxide was observed.
Optical quality assurance of GEM foils Hildén, T.; Brücken, E.; Heino, J. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
01/2015, Letnik:
770
Journal Article
Recenzirano
Odprti dostop
An analysis software was developed for the high aspect ratio optical scanning system in the Detector Laboratory of the University of Helsinki and the Helsinki Institute of Physics. The system is used ...e.g. in the quality assurance of the GEM-TPC detectors being developed for the beam diagnostics system of the SuperFRS at future FAIR facility. The software was tested by analyzing five CERN standard GEM foils scanned with the optical scanning system. The measurement uncertainty of the diameter of the GEM holes and the pitch of the hole pattern was found to be 0.5μm and 0.3μm, respectively. The software design and the performance are discussed. The correlation between the GEM hole size distribution and the corresponding gain variation was studied by comparing them against a detailed gain mapping of a foil and a set of six lower precision control measurements. It can be seen that a qualitative estimation of the behavior of the local variation in gain across the GEM foil can be made based on the measured sizes of the outer and inner holes.
The dosimetric response of silicon diodes produced with distinct engineering technologies, Magnetic Czochralski (MCz), and standard Float Zone (Fz), has been investigated, aiming at their use for ...online dosimeters in gamma radiation processing applications. The p
+
-n-n
+
junction diodes, 300 µm thick with an active area of 25 mm
2
, are operated as online radiation dosimeters in the short-circuit current mode. In this case, the key dosimetric quantity is the dose rate, which is correlated with the output current from the diode subjected to radiation. Thus, the dose is obtained offline by the integration of the corresponding current signal. The irradiations are performed with an industrial Gammacell
60
Co facility at 2.3–2.44 kGy/h covering doses up to 275 kGy. Under continuous irradiation, both diodes delivered current signals whose intensities decreased with accumulated doses. Mitigation of this decay has been accomplished by pre-irradiating the devices to 700 kGy. Polynomial functions best represent the dose responses for either pristine or preirradiated diodes. The relevant dosimetric parameters as response stability, charge sensitivity, and repeatability of current signals (<5%) reveal the better performance of the MCz diode. It is important to note that the whole dataset fully complies with the international standard protocols for routine dosimeters in radiation processing dosimetry. Regarding radiation damage, which in unbiased diodes manifests primarily in the decay of current sensitivity, the results also showed greater tolerance of the MCz diode. Based on these studies, large availability, and better cost-effectiveness, it is possible to endorse the potential use of MCz devices as online routine dosimeters in radiation processing applications. However, the data reproducibility with the accumulated dose, the dose lifespan, and the effect of the irradiation conditions (e.g., temperature, relative humidity, and dose fractionating) remain to be investigated. Works in this direction are currently in progress.
Optical scanning system for quality control of GEM-foils Kalliokoski, M.; Hilden, T.; Garcia, F. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
02/2012, Letnik:
664, Številka:
1
Journal Article
Recenzirano
An optical scanning system was commissioned and further developed in the Detector Laboratory of Helsinki Institute of Physics and University of Helsinki. It was designed to automatically scan, ...perform on-line analysis and to classify the overall quality of GEM-foils especially of the GEM-TPC detectors for Super-FRS at FAIR. The optical scanning system consists of precision positioning table, lighting, optics and operating system with analysis software. It has active scanning area of 95×95
cm
2 and it can study this area with the minimum resolution of 128
lp/mm. Performance of the system and first results from the GEM-foil uniformity and quality analysis are presented.
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