Modulation Analysis in Macro-Molecular Communications

Molecular communication (MC) involves the transmission of information using particles (i.e., molecules). Research into the field has been dominated by micro-scale, and most of the effects of macro-scale communication have yet to be studied. In this paper, the modulation and transmission of MC at macro-scale are investigated. For the transmitter, an in-house-built odor generator was used, and as the detector, a mass spectrometer with a quadrupole mass analyzer was employed. Various 2-level, 4-level, and 8-level modulation schemes were tested experimentally. A simulation framework, developed for the first time, was used for comparison with the experimental results. It was shown that communication can be modeled using a variant of the advection-diffusion equation and that it gives good agreement with the experimental results. A symbol-error-rate (SER) analysis of both the experimental and simulation results was analyzed. It was found that increasing the distance has a detrimental effect on both the channel capacity and the SER, whereas velocity and diffusivity have a decreasing effect on the SER and an increasing effect on the channel capacity. A channel model was developed based on the asymmetric behavior of the communications, and the optimal sampling period was developed that subsequently permitted analysis of the ISI of the communications scheme

Direct analysis and monitoring of organosulphur compounds in the gaseous phase using portable mass spectrometry

Organosulphides are ubiquitous in the natural world and are important in the agriculture, pharmaceuticals and petrochemical sectors.</p

Analysis of volatile emissions from grape berries infected with Aspergillus carbonarius using hyphenated and portable mass spectrometry

Mycotoxins represent a serious risk for human and animal health. Οchratoxin A (OTA) is a carcinogenic mycotoxin produced by A. carbonarius that constitutes a severe problem for viticulture. In this study, we investigate the development of novel detection and on-line monitoring approaches for the detection of OTA in the field (i.e. out of the chemical laboratory) using advanced molecular sensing. Both stand-alone and hyphenated mass spectrometry (MS) based systems (e.g. Time-of-Flight ToF–MS and gas chromatography GC combined with MS) and compact portable membrane inlet MS (MIMS) have been employed for the first time to detect and monitor volatile emissions of grape berries infected by the fungus Aspergillus carbonarius. In vacuo (electron impact—EI) and ambient ionisation (electrospray ionisation—ESI) techniques were also examined. On-line measurements of the volatile emissions of grape berries, infected by various strains of A. carbonarius with different toxicity levels, were performed resulting in different olfactory chemical profiles with a common core of characteristic mass fragments, which could be eventually used for on-site detection and monitoring allowing consequent improvement in food security.ISSN:2045-232

Analysis of chlorinated hydrocarbons in gas phase using a portable membrane inlet mass spectrometer

A compact portable membrane inlet mass spectrometer (MIMS) has been used for the first time to detect and monitor, both qualitatively and quantitatively, volatile chlorinated hydrocarbons in the gaseous phase.</p

Portable mass spectrometry for the direct analysis and quantification of volatile halogenated hydrocarbons in the gas phase

Field chemical analysis (FCA) of volatile halogenated hydrocarbons is a highly debated topic of widespread interest due to the significant negative impact of these compounds on public health, on ecosystems and in the environment (e.g. destruction of the stratospheric ozone).</p

Mobile mass spectrometry for water quality monitoring of organic species present in nuclear waste ponds

This work uses a portable mass spectrometer (MS) for lab-based water quality monitoring of organic compounds, which are present in highly toxic nuclear waste ponds.</p

In-Situ Analysis of Essential Fragrant Oils Using a Portable Mass Spectrometer

A portable mass spectrometer was coupled to a direct inlet membrane (DIM) probe and applied to the direct analysis of active fragrant compounds (3-methylbutyl acetate, 2-methyl-3-furanthiol, methyl butanoate, and ethyl methyl sulfide) in real time. These fragrant active compounds are commonly used in the formulation of flavours and fragrances. Results obtained show that the portable mass spectrometer with a direct membrane inlet can be used to detect traces of the active fragrant compounds in complex mixtures such as essential fragrant oils and this represents a novel in-situ analysis methodology. Limits of detection (LOD) in the sub-ppb range (< 2.5 pg) are demonstrated. Standard samples in the gaseous phase presented very good linearity with RSD % at 5 to 7 for the selected active fragrant compounds (i.e., isoamyl acetate, 2-methyl-3-furanthiol, methyl butanoate, and methyl ethyl sulphide). The rise and fall times of the DIM probe are in the ranges from 15 to 31 seconds and 23 to 41 seconds, respectively, for the standard model compounds analysed. The identities of the fragrance active compounds in essential oil samples (i.e., banana, tangerine, papaya, and blueberry muffin) were first identified by comparison with a standard fragrance compounds mixture using their major fragment peaks, the NIST standard reference library, and gas chromatography mass spectrometry (GC-MS) analysis. No sample preparation is required for analysis using a portable mass spectrometer coupled to a DIM probe, so the cycle time from ambient air sampling to the acquisition of the results is at least 65 seconds