Structured calculational proof

We propose a new format for writing proofs, calledstructured calculational proof. The format resembles the calculational style already familiar to many computer scientists, but extends it to allow the hierarchical decomposition of larger proofs into smaller ones. Structured calculation is actually an alternative presentation of natural deduction, a style of reasoning which uses hierarchical decomposition to great effect, but which is traditionally expressed in a notation that is inconvenient for writing calculational proofs. The hierarchical nature of structured calculational proofs can be used for browsing proofs in electronic publications.     

Mid-clavicle fractures in adults: end result study after conservative treatment

OBJECTIVE: The aim of the present study was to analyze the long-term outcome of mid-clavicle fractures in adults and to evaluate the clinical importance of displacement and fracture comminution. DESIGN: Two hundred twenty-five mid-clavicular fractures that had been nonsurgically treated at Malm? University Hospital were retrospectively evaluated, both clinically and radiographically, an average of seventeen years after injury. There were seventy-one undisplaced fractures, sixty-nine displaced two-fragment fractures, and eighty-five displaced and comminuted fractures. The average patient age at the time of trauma was thirty-three years (range 15 to 70 years). Patients were interviewed, and careful clinical and radiological examination of their shoulders was performed. Two patients had experienced transient neuritis, and another two underwent operative treatment because of progressive neuropathy. SETTING: All 225 consecutive patients were treated primarily at the Malm? University Hospital, which serves the Malm? city population (250,000). PATIENTS/PARTICIPANTS: Since the beginning of this century, all radiographs taken at the Malm? University Hospital have been classified and filed for easy retrieval. In this retrospective study, all patients treated between 1970 and 1979 were identified, and those still living were called for follow-up examination. INTERVENTION: Of the 225 fractures reviewed, 197 fractures were originally treated with a figure-of-eight splint for an average period of three weeks without any attempt to reduce the displaced fractures; twenty-four patients were allowed immediate free shoulder mobilization. MAIN OUTCOME MEASUREMENTS: Clinical rating and healing were the main outcome measurements. RESULTS: At follow-up, 185 shoulders were asymptomatic. Thirty-nine shoulders had moderate pain and were rated as fair, and one patient was rated as poor. One hundred twenty-five of the fractures had healed normally, fifty-three were malunited with persistent fracture displacement, and seven were nonunions; nonunion was significantly more prevalent in cases with displaced fractures. Forty malunited fractures and three nonunions were rated as good. CONCLUSIONS: This review demonstrates that few patients with fractures of the mid-part of the clavicle require operative treatment.     

Computer generated phase holograms (kinoforms) for millimeter and submillimeter wavelengths

Computer generated Fourier transform phase holograms, known as kinoforms, have been synthesized, manufactured and their performance evaluated at a wavelength of 3 mm (100 GHz). The kinoforms were synthesized to give a prescribed far-field intensity distribution and manufactured by milling the computed kinoform surface relief into a Teflon plate, using a numerically controlled milling machine. The measured diffraction efficiencies exceed 50 percent. Millimeter-wave kinoforms can be used in various quasi-optical applications,e.g. distributing a local oscillator signal to an array of detector elements in heterodyne receivers.     

Effluent from drug manufactures contains extremely high levels of pharmaceuticals

It is generally accepted that the main route for human pharmaceuticals to the aquatic environment is via sewage treatment plants receiving wastewater from households and hospitals. We have analysed pharmaceuticals in the effluent from a wastewater treatment plant serving about 90 bulk drug manufacturers in Patancheru, near Hyderabad, India--a major production site of generic drugs for the world market. The samples contained by far the highest levels of pharmaceuticals reported in any effluent. The high levels of several broad-spectrum antibiotics raise concerns about resistance development. The concentration of the most abundant drug, ciprofloxacin (up to 31,000 microg/L) exceeds levels toxic to some bacteria by over 1000-fold. The results from the present study call for an increased focus on the potential release of active pharmaceutical ingredients from production facilities in different regions.     

How to Manage Complex,Multinational R&D Projects Successfully

Abstract

The globalization of markets, mergers of international companies, and integration of managerial and business processes in global corporations are changing project management fundamentals. A clearly recognizable trend in multinational companies since the mid-1980s has been globalization of R&D and competence portfolios.

Applied development is usually conducted in the form of a distributed project organization. A project team is formed across geographical, organizational, and cultural boundaries, engaging in a project with a global focus. Although a multinational project organization has great potential in many dimensions, there is no doubt that the execution of a distributed high technological project is still a great challenge.

This article identifies success factors in the management of distributed projects with global goals. The authors have focused on the practical experiences of the execution of complex multinational projects in the area of applied system development for power industry.     

Films of Graphene Nanomaterials Formed by Ultrasonic Spraying of Their Stable Suspensions

Graphene, a two-dimensional carbon allotrope, exhibits excellent optoelectronic properties. The assembly of graphene into films provides a platform to deepen the study of its interaction with varying surfaces, to engineer devices, and to develop functional materials. A general approach to produce graphene films consists of preparing a dispersion and laying it on a substrate of choice, followed by solvent evaporation. Here, we report the preparation of stable suspensions of new types of graphene nanomaterials namely, graphene nanoflowers (GNFs) and multi-layer graphene (MLG) flakes, in ethanol, N,N-dimethylformamide (DMF), and N-methyl-2-pyrrolidone (NMP). Sprayable suspensions of both GNFs and MLG were prepared in DMF/ethanol, which showed high stability, without addition of any surfactant. The stable suspensions were used to deposit micrometer-thick MLG/GNF films on glass substrates. Calculations of initial droplet size and of timescale of droplet evaporation are performed and possible thermophoretic effects on droplet deposition discussed as well. Coating glass substrates with a methacrylic acid–methyl methacrylate (MA) copolymer prior to the deposition significantly improved the adhesion of the nanomaterials to the substrate. With the MA coating, a substrate coverage of nearly 100% was achieved at 14-min spraying time for 0.05 wt% GNF and 0.1 wt% MLG suspensions. Raman spectra of the GNF and MLG films reveal that the films were made of MLG in which the individual graphene layers rotated from each other as in turbostratic graphene. This work provides a general approach to prepare graphene nanomaterial suspensions and to create films for a variety of applications. The spraying process applied in the current work is highly scalable and allows control of film characteristics through process parameters.

Copyright 2015 American Association for Aerosol Research     

Common Breaks in Means for Cross‐Correlated Fixed‐T Panel Data

This note considers a panel data model in which the variable of interest has undergone a common structural break in the mean. The object of interest is the unknown breakpoint. The challenge is to device an estimator that is consistent when the data are cross‐correlated and the number of time periods T is fixed and cannot be increased without bound. The proposed solution involves taking an already existing estimator initially proposed for cross‐section uncorrelated panels and applying it to defactored data. Consistency is established as the number of cross‐section units N grows large, and is verified in small samples using Monte Carlo simulation.     

Precipitation Kinetics During Post-heat Treatment of an Additively Manufactured Ferritic Stainless Steel

Metallurgical and Materials Transactions A - The microstructure response of laser-powder bed fusion (L-PBF)-processed ferritic stainless steel (AISI 441) during post-heat treatments is studied in...