Production of Magnetic Arsenic-Phosphorus Alloy Nanoribbons with Small Band Gaps and High Hole Conductivities

Quasi-1D nanoribbons provide a unique route to diversifying the properties of their parent 2D nanomaterial, introducing lateral quantum confinement and an abundance of edge sites. Here, a new family of nanomaterials is opened with the creation of arsenic-phosphorus alloy nanoribbons (AsPNRs). By ionically etching the layered crystal black arsenic-phosphorus using lithium electride followed by dissolution in amidic solvents, solutions of AsPNRs are formed. The ribbons are typically few-layered, several micrometers long with widths tens of nanometers across, and both highly flexible and crystalline. The AsPNRs are highly electrically conducting above 130 K due to their small band gap (ca. 0.035 eV), paramagnetic in nature, and have high hole mobilities, as measured with the first generation of AsP devices, directly highlighting their properties and utility in electronic devices such as near-infrared detectors, quantum computing, and charge carrier layers in solar cells.

Sample preparation methods for optimal HS-AFM analysis: Duplex stainless steel

The contact mode high-speed atomic force microscope (AFM) operates orders of magnitude faster than conventional AFMs. It is capable of capturing multiple frames per second with nanometre-scale lateral resolution and subatomic height resolution. This advancement in imaging rate allows for microscale analysis across macroscale surfaces, making it suitable for applications across materials science. However, the quality of the surface analysis obtained by high-speed AFM is highly dependent upon the standard of sample preparation and the resultant final surface finish. In this study, different surface preparation techniques that are commonly implemented within metallurgical studies are compared for samples of SAF 2205 duplex stainless steel. It was found that, while acid etching and electrolytic etching were optimal for the low resolution of optical microscopy, these methods were less suited for analysis by high resolution high-speed AFM. Mechanical and colloidal silica polishing was found to be the optimal method explored, as it provided a gentle etch of the surface allowing for high quality topographic maps of the sample surface.

A comparison of two high spatial resolution imaging techniques for determining carbide precipitate type and size in ferritic 9Cr-1Mo steel

Two high spatial resolution imaging techniques, focused gallium ion beam imaging in conjunction with XeF₂ gas (FIB/XeF₂) and high-speed atomic force microscopy (HS-AFM), were used to analyse 9Cr-1Mo ferritic steel samples, which had been exposed for extended periods to hot CO₂ gas containing traces of CO, H₂, H₂O and CH₄. The carbide precipitates embedded in the metal matrix were observed and their morphology, size and spatial distribution were quantified using these two techniques. The lower resolution of the FIB/XeF₂ imaging technique suggested that small carbide precipitates (<50 nm) may be missed, while the existence of a limited flow layer introduced by sample preparation may influence the HS-AFM results. The gallium ion beam was used to remove a thin oxide layer of approximately 50 nm from sample surfaces prior to FIB/XeF₂ imaging, avoiding the influence of surface contamination. HS-AFM provided higher resolution (∼5 nm) than FIB/XeF₂ imaging. A quantitative comparison of the experimental data confirmed the value of both FIB/XeF₂ and HS-AFM for imaging carbide precipitates, while clarifying their strengths and limitations.

Radiological comparison of a FDNPP waste storage site during and after construction

The clean-up effort that is occurring across the region affected by the 2011 Fukushima Daiichi Nuclear Power Plant accident is unprecedented in its magnitude as well as the financial cost that will eventually result. A major component of this remediation is the stripping of large volumes of material from the land surface, depositing this into large waste storage bags before placing these 1 cubic meter bags into specially constructed stores across Fukushima Prefecture. In this work, using an unmanned aerial vehicle to perform radiological surveys of a site, the time-resolved distribution of contamination during the construction of one of these waste storage sites was assessed. The results indicated that radioactive material was progressively leaching from the store into the surrounding environment. A subsequent survey of the site conducted eight months later revealed that in response to this survey and remedial actions, the contamination issue once existing on this site had been successfully resolved. Such results highlight the potential of low-altitude unmanned aerial systems to easily and rapidly assess site-wide changes over time - providing highly-visual results; therefore, permitting for prompt remedial actions to be undertaken as required. Use of UAV radiation mapping and airborne photogrammetry to produce a time-resolved assessment of remediation efforts within a Fukushima temporary storage facility.

Validation of a novel radiation mapping platform for the reduction of operator-induced shielding effects

With extensive remediation currently ongoing because of the Fukushima Daiichi Nuclear Power Plant accident, there exists the even greater need to provide a system with which the distribution of radiation (specifically radiocesium) can be rapidly determined across extensive areas, yet at high (metre or sub-metre) spatial resolutions. Although a range of potential survey methods have been utilised (e.g. fixed-wing aircraft, helicopter, vehicular and more-recently unmanned aerial vehicle) to characterise the distribution of radiological contamination, ground-based (on-foot) methods that employ human operatives to traverse sites of interest remains one of the primary methods through which to perform routine radiological site surveys. Through the application of a newly-developed platform carried as a backpack-contained unit, it was possible to map sites at twice the rate previously possible-reducing not only the exposure time of the operator to ionising radiation, but also dramatically reducing the level of radiation attenuation (introduced by the operator) onto the detector. Like magnetometry platforms used during geological ore prospecting, this system was similarly boom-based, extending sideways away from the central operator. While conventional radiological survey platforms require a correction be performed on the data to account for the carrier (aircraft, vehicle or human) interception and attenuation incident radiation-this system is shown to not require such a retrospective correction.

Source identification of uranium-containing materials at mine legacy sites in Portugal

Whilst prior nuclear forensic studies have focused on identifying signatures to distinguish between different uranium deposit types, this paper focuses on providing a scientific basis for source identification of materials from different uranium mine sites within a single region, which can then be potentially used within nuclear forensics. A number of different tools, including gamma spectrometry, alpha spectrometry, mineralogy and major and minor elemental analysis, have been utilised to determine the provenance of uranium mineral samples collected at eight mine sites, located within three different uranium provinces, in Portugal. A radiation survey was initially conducted by foot and/or unmanned aerial vehicle at each site to assist sample collection. The results from each mine site were then compared to determine if individual mine sites could be distinguished based on characteristic elemental and isotopic signatures. Gamma and alpha spectrometry were used to differentiate between samples from different sites and also give an indication of past milling and mining activities. Ore samples from the different mine sites were found to be very similar in terms of gangue and uranium mineralogy. However, rarer minerals or specific impurity elements, such as calcium and copper, did permit some separation of the sites examined. In addition, classification rates using linear discriminant analysis were comparable to those in the literature.

Development and validation of a high-resolution mapping platform to aid in the public awareness of radiological hazards

The distribution, quantification and exposure-related effects of radiation in the environment, arising from both natural and anthropogenic sources, is of great (and growing) concern for global populations. Recent events at the Fukushima Daiichi Nuclear Plant (FDNPP) have further highlighted the importance of developing radiation mapping technologies that not only contribute to the continued assessment of contamination, but can serve as an educational tool for members of the public regarding both its behaviour and extent. With an even greater number of people possessing smart-phone technology, a lightweight and portable 'connected system' has been developed to demonstrate to users the calibrated radioactive dose rate in an area, viewable in real-time through a dedicated phone application. As well as allowing for system users to be alerted where variations in dose rate are experienced, the combined results from multiple systems are viewable through a custom-built desktop application-permitting the output obtained via any number of units to be similarly displayed in real-time. A successful initial trialling of the system is described at a former tin mine in Cornwall (south-west England)-known to exhibit low, but identifiable radiation anomalies in discrete areas. Additional applications outside of its educational usage are also discussed.

Application of airborne photogrammetry for the visualisation and assessment of contamination migration arising from a Fukushima waste storage facility

Airborne systems such as lightweight and highly portable unmanned aerial vehicles (UAVs) are becoming increasingly widespread in both academia and industry - with an ever-increasing range of applications, including (but not limited to), air quality sampling, wildlife monitoring and land-use mapping. In this work, high-resolution airborne photogrammetry obtained using a multi-rotor system operating at low survey altitudes, is combined with ground-based radiation mapping data acquired at an interim storage facility for wastes removed as part of the large-scale Fukushima clean-up program. The investigation aimed to assess the extent to which the remediation program at a specific site has contained the stored contaminants, as well as present a new methodology for rapidly surveying radiological sites globally. From the three-dimensional rendering of the site of interest, it was possible to not only generate a powerful graphic confirming the elevated radiological intensity existing at the location of the waste bags, but also to also illustrate the downslope movement of contamination due to species leakage from the large 1m³ storage bags. The entire survey took less than 1 h to perform, and was subsequently post-processed using graphical information software to obtain the renderings. The conclusions within this study not only highlight the usefulness of incorporating three-dimensional renderings within radiation mapping protocols, but also conclude that current methods of monitoring these storage facilities in the long term could be improved through the integration of UAVs within the standard protocol.

A study of dynamic nanoscale corrosion initiation events using HS-AFM

Using HS-AFM measurements it was possible to calculate, and subsequently model, the volumes of metal reacting with respect to time, and so the current densities and ionic fluxes at work. In this manner, the local electrochemistry at nanoscale reaction sites may be reconstructed.

Single Crystal, Luminescent Carbon Nitride Nanosheets Formed by Spontaneous Dissolution

A primary method for the production of 2D nanosheets is liquid-phase delamination from their 3D layered bulk analogues. Most strategies currently achieve this objective by significant mechanical energy input or chemical modification but these processes are detrimental to the structure and properties of the resulting 2D nanomaterials. Bulk poly(triazine imide) (PTI)-based carbon nitrides are layered materials with a high degree of crystalline order. Here, we demonstrate that these semiconductors are spontaneously soluble in select polar aprotic solvents, that is, without any chemical or physical intervention. In contrast to more aggressive exfoliation strategies, this thermodynamically driven dissolution process perfectly maintains the crystallographic form of the starting material, yielding solutions of defect-free, hexagonal 2D nanosheets with a well-defined size distribution. This pristine nanosheet structure results in narrow, excitation-wavelength-independent photoluminescence emission spectra. Furthermore, by controlling the aggregation state of the nanosheets, we demonstrate that the emission wavelengths can be tuned from narrow UV to broad-band white. This has potential applicability to a range of optoelectronic devices.

High-resolution radiation mapping to investigate FDNPP derived contaminant migration

As of March 2016, five years will have passed since the earthquake and ensuing tsunami that crippled the Fukushima Daiichi Nuclear Power Plant on Japan's eastern coast, resulting in the explosive release of significant quantities of radioactive material. Over this period, significant time and resource has been expended on both the study of the contamination as well as its remediation from the affected environments. Presented in this work is a high-spatial resolution foot-based radiation mapping study using gamma-spectrometry at a site in the contaminated Iitate Village; conducted at different times, seventeen months apart. The specific site selected for this work was one in which consistent uniform agriculture was observed across its entire extent. From these surveys, obtained from along the main northwest trending line of the fallout plume, it was possible to determine the rate of reduction in the levels of contamination around the site attributable to the natural decay of the radiocesium, remediation efforts or material transport. Results from the work suggest that neither the natural decay of radiocesium nor its downward migration through the soil horizons were responsible for the decline in measured activity levels across the site, with the mobilisation of contaminant species likely adhered to soil particulate and the subsequent fluvial transport responsible for the measurable reduction in activity. This transport of contaminant via fluvial methods has already well studied implications for the input of contaminant material entering the neighbouring Pacific Ocean, as well as the deposition of material along rivers within previously decontaminated areas.

Low altitude unmanned aerial vehicle for characterising remediation effectiveness following the FDNPP accident

On the 12th of March 2011, The Great Tōhoku Earthquake occurred 70 km off the eastern coast of Japan, generating a large 14 m high tsunami. The ensuing catalogue of events over the succeeding 12 d resulted in the release of considerable quantities of radioactive material into the environment. Important to the large-scale remediation of the affected areas is the accurate and high spatial resolution characterisation of contamination, including the verification of decontaminated areas. To enable this, a low altitude unmanned aerial vehicle equipped with a lightweight gamma-spectrometer and height normalisation system was used to produce sub-meter resolution maps of contamination. This system provided a valuable method to examine both contaminated and remediated areas rapidly, whilst greatly reducing the dose received by the operator, typically in localities formerly inaccessible to ground-based survey methods. The characterisation of three sites within Fukushima Prefecture is presented; one remediated (and a site of much previous attention), one un-remediated and a third having been subjected to an alternative method to reduce emitted radiation dose.

The use of unmanned aerial systems for the mapping of legacy uranium mines

Historical mining of uranium mineral veins within Cornwall, England, has resulted in a significant amount of legacy radiological contamination spread across numerous long disused mining sites. Factors including the poorly documented and aged condition of these sites as well as the highly localised nature of radioactivity limit the success of traditional survey methods. A newly developed terrain-independent unmanned aerial system [UAS] carrying an integrated gamma radiation mapping unit was used for the radiological characterisation of a single legacy mining site. Using this instrument to produce high-spatial-resolution maps, it was possible to determine the radiologically contaminated land areas and to rapidly identify and quantify the degree of contamination and its isotopic nature. The instrument was demonstrated to be a viable tool for the characterisation of similar sites worldwide.

Large area high-speed metrology SPM system

We present a large area high-speed measuring system capable of rapidly generating nanometre resolution scanning probe microscopy data over mm(2) regions. The system combines a slow moving but accurate large area XYZ scanner with a very fast but less accurate small area XY scanner. This arrangement enables very large areas to be scanned by stitching together the small, rapidly acquired, images from the fast XY scanner while simultaneously moving the slow XYZ scanner across the region of interest. In order to successfully merge the image sequences together two software approaches for calibrating the data from the fast scanner are described. The first utilizes the low uncertainty interferometric sensors of the XYZ scanner while the second implements a genetic algorithm with multiple parameter fitting during the data merging step of the image stitching process. The basic uncertainty components related to these high-speed measurements are also discussed. Both techniques are shown to successfully enable high-resolution, large area images to be generated at least an order of magnitude faster than with a conventional atomic force microscope.

Lightweight aerial vehicles for monitoring, assessment and mapping of radiation anomalies

The Fukushima Daiichi nuclear power plant (FDNPP) incident released a significant mass of radioactive material into the atmosphere. An estimated 22% of this material fell out over land following the incident. Immediately following the disaster, there was a severe lack of information not only pertaining to the identity of the radioactive material released, but also its distribution as fallout in the surrounding regions. Indeed, emergency aid groups including the UN did not have sufficient location specific radiation data to accurately assign exclusion and evacuation zones surrounding the plant in the days and weeks following the incident. A newly developed instrument to provide rapid and high spatial resolution assessment of radionuclide contamination in the environment is presented. The device consists of a low cost, lightweight, unmanned aerial platform with a microcontroller and integrated gamma spectrometer, GPS and LIDAR. We demonstrate that with this instrument it is possible to rapidly and remotely detect ground-based radiation anomalies with a high spatial resolution (<1 m). Critically, as the device is remotely operated, the user is removed from any unnecessary or unforeseen exposure to elevated levels of radiation.

Improving the signal-to-noise ratio of high-speed contact mode atomic force microscopy

During high-speed contact mode atomic force microscopy, higher eigenmode flexural oscillations of the cantilever have been identified as the main source of noise in the resultant topography images. We show that by selectively filtering out the frequencies corresponding to these oscillations in the time domain prior to transforming the data into the spatial domain, significant improvements in image quality can be achieved.

Modelling oscillatory flexure modes of an atomic force microscope cantilever in contact mode whilst imaging at high speed

Understanding the modal response of an atomic force microscope is important for the identification of image artefacts captured using contact-mode atomic force microscopy (AFM). As the scan rate of high speed AFM increases, these modes present themselves as ever clearer noise patterns as the frequency of cantilever vibration falls under the frequency of pixel collection. An Euler-Bernoulli beam equation is used to simulate the flexural modes of the cantilever of an atomic force microscope as it images a hard surface in contact mode. Theoretical results are compared with experimental recordings taken in the high speed regime, as well as previous analytical results. It is shown that the model can capture the mode shapes and resonance properties of the first four eigenmodes.

High-speed atomic force microscopy in slow motion--understanding cantilever behaviour at high scan velocities

Using scanning laser Doppler vibrometer we have identified sources of noise in contact mode high-speed atomic force microscope images and the cantilever dynamics that cause them. By analysing reconstructed animations of the entire cantilever passing over various surfaces, we identified higher eigenmode oscillations along the cantilever as the cause of the image artefacts. We demonstrate that these can be removed by monitoring the displacement rather than deflection of the tip of the cantilever. We compare deflection and displacement detection methods whilst imaging a calibration grid at high speed and show the significant advantage of imaging using displacement.

Experimental observation of contact mode cantilever dynamics with nanosecond resolution

We report the use of a laser Doppler vibrometer to measure the motion of an atomic force microscope contact mode cantilever during continuous line scans of a mica surface. With a sufficiently high density of measurement points the dynamics of the entire cantilever beam, from the apex to the base, can be reconstructed. We demonstrate nanosecond resolution of both rectangular and triangular cantilevers. This technique permits visualization and quantitative measurements of both the normal and lateral tip sample interactions for the first and higher order eigenmodes. The ability to derive quantitative lateral force measurements is of interest to the field of microtribology/nanotribology while the comprehensive understanding of the cantilever's dynamics also aids new cantilever designs and simulations.

The planning process in occupational therapy: perceptions of adult rehabilitation patients

OBJECTIVES

The purpose of this study was to learn about (a) adult physical rehabilitation patients' perceptions of their involvement in the treatment planning process (goal setting, treatment planning, outcome evaluation), (b) their valuation of occupational therapy, and (c) how they would describe their interpersonal relationships with their occupational therapists.

METHOD

Fifteen subjects who had received occupational therapy were interviewed. The transcripts were independently and jointly reviewed by the authors to answer five research questions.

RESULTS

Most of the subjects indicated that they had been involved in occupational therapy goal setting; treatment planning; and outcome evaluation, albeit this indication was weak. They also valued the occupational therapy services they received. Eight described positive interpersonal interactions with their therapists, and seven provided no information.

CONCLUSION

Patients receiving occupational therapy services are involved in goal setting, treatment planning, and outcome evaluations; however, their involvement varies and can be difficult for them to identify and describe. Because of increasing societal emphasis on patient rights and participation (e.g., consumerism, health professions standards, health care accreditation criteria, health care legislation) and the likelihood that health care funding will be used for services linked to patient goals, occupational therapy practitioners could become more overt and systematic in involving patients in the planning process. Increasing patient involvement in planning may result in more individualized treatment and more effective use of health care dollars.

A system for involving patients in program planning

Although standards exist that require occupational therapists and other health care professionals to include patients in the treatment planning process, our observations lead us to believe that patient involvement is not being maximized. The Patient Participation System allows therapists to actively involve patients in a systematic goal-setting process. The initial results of the use of this system indicate that patients can be effectively involved in establishing personalized, specific goals; identifying outcomes; and evaluating treatment effectiveness.

Clinical reasoning process in physical therapy

The purpose of this descriptive study was to analyze physical therapists' clinical problem solving and compare the results with physicians' clinical problem solving. Ten skilled physical therapy clinicians were observed as they performed an initial interview with a patient. Their performance was audiotaped and later analyzed. The therapists defined their problem lists and developed treatment plans early in the interview, as they gathered data. This clinical problem-solving sequence is comparable to a method reported in the literature that is used by physicians. This model of clinical problem solving based on actual performance of clinicians can be used to train physical therapy students and, perhaps, to refine clinical evaluation skills.

Effects of instruction in basic communication skills on physical therapists and physical therapy students

The purpose of this study was to test the hypothesis that laboratory instruction within a one-semester course could significantly change the communication skills of physical therapists and physical therapy students in the desired direction. Effective use of communication skills, the dependent variable, is defined in the counseling psychology literature. The independent variables were parts of two academic courses for physical therapists: one for graduate students (physical therapists) and one for undergraduate students. Data from the two groups were treated separately in a one-group, pretest-posttest, quasi-experimental design. The test for overall effect of changes in communication skills of undergraduate students was significant at the .0001 level. Post hoc tests for changes in use of seven specific skills varied in significance level from .8 to .0001. Education techniques, not subject variability, accounted for most of the change. Graduate student data did not reach traditional significance levels, but encouraging trends were noted. Results can be interpreted in terms of education, clinical experience, and measurement tools.

Instructional style preferences: physical therapy faculty members in the United States

The purpose of this study was to describe the instructional styles of physical therapy faculty in basic professional programs in the United States in the academic year 1977-78. The Instructional Styles Inventory of Canfield and Canfield was used to test 311 respondents (61% of the total basic preparation faculty members contacted). The "typical" faculty member is described and compared to the "typical" student described in an earlier study. Commonalities and discrepancies between student learning styles and faculty instructional styles are discussed. A rather unexpectedly high level of agreement between students and faculty as to preferred modes of teaching and learning was demonstrated.

Student-produced empathic responses: the second step in teaching communication skills to allied health supervisors

Two earlier reports have demonstrated the success of a specific curricular plan in teaching potential allied health supervisors to recognize empathic responses in stimulus situations. This study demonstrated that the same instructional content and methodology were also effective in teaching student-supervisors to produce empathic responses in simulated supervisory situations. Experimental and control groups were used, and the experimental group was superior in the test situation at a significance level of p less than .015. Pertinent literature from counselor education is reviewed and its relevance to the education of hospital and health care supervisors is discussed.

Learning style preferences: physical therapy students in the United States

The purpose of this study was to describe the learning style preferences of students enrolled in their first year of basic professional programs in physical therapy in the United States in the academic year 1975 to 1976. The testing instrument used was the Learning Styles inventory developed by Canfield and Lafferty. A sample of 1,099 (40.8% of the total population) was collected. The results have been tabulated using descriptive statistics of means and standard deviations for: 1) total sample, 2) men, and 3) women. The "typical" or "average" physical therapy student is described. These results have important implications for physical therapy educators in terms of arranging their instructional activities to optimize learning.

Abductor digiti quinti shuffleboard: a study in motor learning

The purposes of this study were as follows: (1) to refine prior studies by investigating one muscle which provided all the agonistic motion involved in a novel motor task, (2) the pinpoint the exact time during which motor activity contributed to the final task, (3) to study the electrical changes that occurred in that one muscle as it developed skill, and (4) to compare the results of this study with the previous studies in this series. The muscle chosen for this study was the abductor digiti quinti of the nondominant hand and the novel task involved propelling a small plastic disk into a specific target area. Electromyography and cinematography were used in data collection. No statistically significant differences were found in prelearning and postlearning data with regard to electrical activity, movement time or range of movement. These results support a hypothesis earlier proposed by Payton to the effect that all the the agonists which contribute to a skilled performance begin as a relatively undifferentiated mass of muscle; as learning takes place the various elements of this muscle mass are differentiated into prime movers and auxiliaries. The electrical activity remains essentially the same in the prime movers while a marked reduction is seen in the auxiliary muscles. A reinterpretation of several earlier studies is suggested.

Effects of therapeutic ultrasound on bone marrow in dogs

With a thermocouple in the medullary cavity of one dog's femur, the increases in bone marrow temperature were demonstrated at five different intensities of ultrasound. The right distal femurs of six dogs were treated ten times, three dogs at 1.5 w/cm2 and three dogs at 2.5 w/cm2 each for five minutes. At a later date, two of these dogs received an additional ten minutes of ultrasound at 2.5 w/cm2 for ten treatments. Histological and hematological studies gave presumptive evidence of bone marrow damage and regeneration. A marked increase in oil was also seen in the bone marrow smears.