A simple and reliable system for measuring the refractive index ofliquids using a position-sensitive detector

A simple and yet efficient apparatus for the measurement of the refractive index of liquids has been developed, with the purpose of controlling adulteration in liquids of everyday use. In the system, the index of refraction of the liquid under test is determined by measuring the lateral displacement of a laser beam, that passes obliquely through a rectangular cell filled with the liquid under characterization. The lateral displacement is accurately determined by a position-sensitive detector. A careful analysis of the errors that can be obtained with the system has been carried out, that yielded calibration curves for easy on-line correction. To characterize the performance of the system, a series of tests has been performed on simple liquids, under controlled conditions. The residual errors have proven to be within one part over 10³. The proposed system is suitable for easy automation, obtaining simple and accurate measurements that can be performed also for volatile compounds     

Building a drug development database: challenges in reliable data availability

Abstract

Context: Policy and legislative efforts to improve the biomedical innovation process must rely on a detailed and thorough analysis of drug development and industry output.

Objective: As part of our efforts to build a publicly-available database on the characteristics of drug development, we present work undertaken to test methods for compiling data from public sources. These initial steps are designed to explore challenges in data extraction, completeness and reliability. Specifically, filing dates for Investigational New Drugs (IND) applications with the U.S. Food and Drug Administration (FDA) were chosen as the initial objective data element to be collected.

Materials and methods: FDA’s Drugs@FDA database and the Federal Register (FR) were used to collect IND dates for the 587 New Molecular Entities (NMEs) approved between 1994 and 2014. When available, the following data were captured: approval date, IND number, IND date and source of information.

Results: At least one IND date was available for 445 (75.8%) of the 587 NMEs. The Drugs@FDA database provided IND dates for 303 (51.6%) NMEs and the FR contributed with 297 (50.6%) IND dates. Out of the 445 NMEs for which an IND date was obtained, 274 (61.6%) had more than one date reported.

Discussion: Key finding of this paper is a considerable inconsistency in reliably available or reported data elements, in this particular case, IND application filing dates as assembled from publicly-available sources.

Conclusion: Our team will continue to focus on finding ways to collect relevant information to measure impact of drug innovation.     

Design and evaluation of a low-cost multistatic netted radar system

This paper reports on the design and initial evaluation of a low-cost multistatic radar system that exploits digital components. The system is based on a commercial-off-the-shelf and open architecture approach, using a direct digital synthesiser, a field programmable gate array and a digital signal processor as core components. Instrument function testing, calibration and the results of the initial field tests are reported. Some of the first multistatic experimental results are reported and demonstrate a number of aspects of the performance of such a configuration. The advantages and limitations of a low-cost digital radar design are discussed and further system development possibilities outlined. This system will enable the collection of a wide range of novel multistatic data and has the potential to demonstrate a number of new radar applications.     

Design and fabrication of a low-cost, multispectral imaging system

This paper reports the design and construction of a low-cost, multispectral imaging system using a single, large format CCD and an array of 18 individual lenses coupled to individual spectral filters. The system allows the simultaneous acquisition of 18 subimages, each with potentially different optical information. The subimages are combined to create a composite image, highlighting the desired spectral information. Because all the subimages are acquired simultaneously, the composite image shows no motion artifact. Although the present configuration uses 17 narrow bandpass optical filters to obtain multispectral information from a scene, the system is designed to be a general purpose, multiaperture platform, easily reconfigured for other multiaperture imaging modes.     

Arduino-based low-cost electrical load tracking system with a long-range mesh network

A system that combines the advantage of the long-range (LoRa) communication method and the structural characteristics of a mesh network for an LoRa mesh network...     

A demonstrator for a low-cost, cordless, multi-carrier spread-spectrum system

Because of the need for spectrally efficient systems for wireless communication, many research activities have been carried out in the area of spread-spectrum techniques. Multi-carrier spread-spectrum (MC-SS) is a new modulation technique with better spectral properties than direct-sequence spread-spectrum (DS-SS). In this paper, a new MC-SS system is introduced. A customized surface acoustic wave (SAW) filter has been designed as a fast analog correlator. A demonstrator testbed has been developed for the 2.4-GHz industrial, scientific, and medical (ISM) band. Experimental measurements of the intermediate frequency (IF) and baseband correlation are presented.     

Blockchain-based ubiquitous manufacturing: a secure and reliable cyber-physical system

With product customisation and emerging business opportunities, small and medium manufacturing enterprises (SMEs) must find ways to collaborate and share competency in a trustable manner to survive a turbulent market. Therefore, service industry turns to the manufacturing industry and SMEs migrate to cloud manufacturing (CM) and ubiquitous manufacturing. However, existing platforms use centralised networking, which suffers from security, scalability and big-data problems. In this paper, we propose a blockchain-based platform as a trustable network to eradicate third-party problems, which can improve the scalability, security and big-data problems for SMEs. Our proposed platform is developed based on a consortium blockchain which provides a peer-to-peer communication network between the end user and the service provider. We improve existing consensus mechanism and communication protocol based on a cyber-physical system (CPS), via an autonomous agent. Firstly, we provide a review of cloud manufacturing, ubiquitous manufacturing and blockchain-based manufacturing approaches by highlighting the main problems. Then, the proposed platform, blockchain ubiquitous manufacturing (BCUM), is explained, based on its architecture, consensus algorithm and CPS, with the help of autonomous agent communication. The proposed platform has been developed for 3D printing companies which are geographically distributed and tested based on network performance and three practical scenarios.     

Designing a reliable leak bio-detection system for natural gas pipelines

Monitoring of natural gas (NG) pipelines is an important task for economical/safety operation, loss prevention and environmental protection. Timely and reliable leak detection of gas pipeline, therefore, plays a key role in the overall integrity management for the pipeline system. Owing to the various limitations of the currently available techniques and the surveillance area that needs to be covered, the research on new detector systems is still thriving. Biosensors are worldwide considered as a niche technology in the environmental market, since they afford the desired detector capabilities at low cost, provided they have been properly designed/developed and rationally placed/networked/maintained by the aid of operational research techniques. This paper addresses NG leakage surveillance through a robust cooperative/synergistic scheme between biosensors and conventional detector systems; the network is validated in situ and optimized in order to provide reliable information at the required granularity level. The proposed scheme is substantiated through a knowledge based approach and relies on Fuzzy Multicriteria Analysis (FMCA), for selecting the best biosensor design that suits both, the target analyte and the operational micro-environment. This approach is illustrated in the design of leak surveying over a pipeline network in Greece.     

RCSM: a reliable critical subsystem model in multi-agent system

针对多主体系统由其自治的软件主体构成带来的故障处理上的困难,研究了多主体系统的可靠性问题,并尝试从主体组层面出发对系统中的故障进行协调处理,提出了一个可靠关键子系统模型(RCSM).RCSM包含三类主体,即中继主体、控制中心主体以及工作主体.此模型使用中继主体封装由工作主体组成的关键子系统,使子系统的拓扑结构对外界不可见,从而避免故障的大范围传播.在子系统内部采用基于任务分配的一致性检查点设置技术实现工作主体的故障恢复.对模型中的控制中心主体则采用了复制技术与团队协作相结合的手段来提高其可靠性.通过仿真实验对RCSM的故障恢复效率及其对系统正常运行效率的影响进行分析,说明了该模型的实用价值.     

A simple and reliable route to prepare high-temperature microwave high-performing absorbers

Journal of Materials Science: Materials in Electronics - With extensive use of electronic devices and communication equipment, serious issue of electromagnetic wave pollution needs to be addressed...     

Reaction-diffusion in a simple pooled chemical system

The reaction scheme based on the cubic autocatalator A + 2B→ 3B B → C is considered in a closed vessel with the reactant Abeing replenished by the slow decay of a precursor Pvia the simple step P→A The concentration of Pis assumed to be very much larger than that of the intermediates Aand Bso that the pooled chemical approximation can be made. Spatial variations are allowed for within the vessel and it is assumed that initially the vessel contains only the reactant Pand that at time ? = 0 a quantity of B,characterized by the parameter β_o; is introduced into some localized region. The long-time behaviour is discussed and it is shown that this depends on the parameters β_oand μ(where μis a non-dimensional parameter representing the reaction rates) with the value of the diffusion parameter λ effectively controlling the form of the transient path leading to the final behaviour. Analytic solutions are derived for the cases when β_ois small and λ is large. These are complemented by numerical solutions for general values of the parameters. It is found that there are three possibilities: a finite equilibrium may be reached with Aand Bhaving constant concentrations, the concentrations of Aand Bmay oscillate, or Bmay die away leaving just the conversion of P to AIn the first two cases it is found that this behaviour is left behind a propagating reaction-diffusion front. The nature of this front is analysed in detail.     

The design of a highly reliable safety critical emergency shutdown system

An emergency shutdown system (ESD) by its nature should be fail-safe. That is, in case of failure in any of its operations, in order to safeguard human life, property and the environment, it should shut down the plant that it controls. However, a complete shutdown, for example, of a petrochemical or nuclear plant is extremely costly. Therefore, as an alternative, the design of highly reliable emergency shutdown systems should be investigated.The major difference between a shutdown system and other control systems is the degree of tolerable operational integrity. A malfunction in the latter is immediately visible and the system can be replaced by a fully operational one. A shutdown system on the other hand is usually, sometimes for years and hopefully forever, `dormant'. When, however, a true emergency situation arises and real demand is placed on it, it must be fully functional. Reliability is of paramount importance. Therefore, besides applying structured design techniques and improved testability other design methods will also need to be incorporated in the final system in order to increase its reliability.     

Electrospun hydroxyapatite fibers from a simple sol-gel system

This work reports the production of hydroxyapatite (HA) sub-micron fibers by combining electrospinning and a non-alkoxide sol-gel system, using cheap precursors. Phosphorus pentoxide (P₂O₅) and calcium nitrate tetrahydrate (Ca(NO₃)₂.4H₂O) were used as precursors of phosphorus and calcium, respectively. The fibers were electrospun from a mixture of the gel formed from the system Ca(NO₃)₂.4H₂O/P₂O₅ with polymeric solutions of polyvinylpyrrolidone (PVP) in water and ethanol/water mixtures. The fibers were analyzed for their morphology (Scanning Electron Microscopy, SEM), chemical composition (Fourier Transform Infrared Spectroscopy, FTIR) and structure (X-ray diffraction, XRD). The fibers obtained were composed mainly of type B carbonated HA with traces of β-tricalcium phosphate (β-TCP). SEM analysis revealed that increasing the concentration of water in the solvent system, used in the preparation of electrospinning solutions, led to fibers with smaller diameters and narrower diameter distribution.     

Optimal arrival rate in a simple queueing system

Over the last decade increasing attention has been devoted to introducing optimization into queueing models. The emphasis has predominantly been upon choosing facilities to minimize cost of servicing a given demand. Recently there has been some discussion of optimal balking rules and charges in order to influence demand. Now the concept of pricing to determine the optimal level of congestion (e.g. on roads) has long been familiar to economists. However, such economic analyses have not been couched in terms of queueing theory nor do recent texts in operational research reflect the economic approach. This paper therefore gives a concise derivation and discussion of the pricing principle in terms of one of the simplest queueing models. A graphical interpretation is also available which should aid in the intuitive understanding of the more sophisticated models referred to. The general implication of these analyses is that, just as providing ‘ excess ” capacity is worth while if it costs less than the cost of delays avoided, so it is also worth while to turn away arrivals or reduce usage as long as the benefit thus sacrificed is more than offset by reduction in cost of delay.     

A low-cost high-definition wireless sensor system utilizing intersymbol interference

A new method for wireless interrogation of a passive SAW sensor with multiple reflectors, utilizing the signal interference during overlap of the sensor's response bursts, is introduced. Within this time interval, the amplitude or the phase, respectively, is measured. By varying the frequency of the relatively long interrogation bursts, the amount of interference and destructive interferences (notches) are searched, respectively. So the measurand influencing the sensor or its identification information can be gained. The principle yields high resolution with a low cost interrogating system. The basic principle, calculations of sensitivity, and experimental results for temperature measurements are presented. The hardware effort and the performance of the system are discussed.     

A simple phoswich system

Normal phoswich detector systems use a combination of NaI(Tl) and CsI(Na) scintillators and require the application of careful pulse-shape discriminator techniques to resolve the two components in the scintillation light output which have decay constants of 250 and 630 ns respectively. These techniques provide a good anticoincidence veto efficiency for a relatively narrow range in the ratio of energy deposits in the two crytals and for a detector system whose temperature is carefully controlled. This paper describes the performance of a simple phoswich which makes use of the fast UV signal from a BaF₂ crystal to provide a prompt veto signal. The performance to be expected from various combinations of a BaF₂ anticoincidence crystal with other primary detectors is presented. These simulations have been verified by simple experimental tests.     

Synthesis and electrochemical performance of a simple and low-cost sulfur/porous carbon composite cathode for rechargeable lithium sulfur battery

The sugar and phenolic resin were used as source materials to prepare porous carbons labeled as PC1 and PC2 respectively, which were activated by chemical methods with CaCO₃ as active agent. Sulfur/porous carbon composites were synthesized by thermally treating a mixture of sublimed sulfur and porous carbon. The morphology, structure, and electrochemical performance of the composite were investigated by scanning electron microscopy, Brunauer–Emmett–Teller, and a variety of electrochemical techniques. The electrochemical measurements show that the SPC2 electrode presents a more favorable electrochemical kinetics than the SPC1 electrode. In comparison with SPC1, it is shown that the rate of Li⁺ diffusion with SPC2 is significantly higher and the charge transfer resistance is much lower. The PC2 with high surface area (735.2 m² g⁻¹) and large pore volume (1.56 cm³ g⁻¹) not only increases the electronic conductivity of composites, but also facilitates transfer of the Li ion in the composite electrode.     

Rapid,simple and low-cost fabrication of BiOBr ultrathin nanocrystals with enhanced visible light photocatalytic activity

BiOBr ultrathin nanocrystals were prepared by a rapid, simple and low-cost route, and characterised by X-ray diffraction, scanning electron microscope, transmission electron microscopy, energy dispersive X-ray, UV–vis diffuse reflectance spectroscopy and electrochemical impedance spectroscopy analyses. The size of the resulting BiOBr ultrathin nanocrystals is about 60–100 nm in width and 15–20 nm in thickness. The photocatalytic activity of the samples was evaluated in terms of the degradation of RhB. Compared with BiOBr three-dimensional microspheres and P₂₅-TiO₂, the BiOBr ultrathin nanocrystals exhibited the best visible-light-induced photocatalytic activity.