Modified Firearm Discharge Residue Analysis utilizing Advanced Analytical Techniques, Complexing Agents, and Quantum Chemical Calculations

The use of gunshot residue (GSR) or firearm discharge residue (FDR) evidence faces some challenges because of instrumental and analytical limitations and the difficulties in evaluating and communicating evidentiary value. For instance, the categorization of GSR based only on elemental analysis of single, spherical particles is becoming insufficient because newer ammunition formulations produce residues with varying particle morphology and composition. Also, one common criticism about GSR practitioners is that their reports focus on the presence or absence of GSR in an item without providing an assessment of the weight of the evidence. Such reports leave the end-used with unanswered questions, such as “Who fired the gun?” Thus, there is a critical need to expand analytical capabilities and enhance the impact of the forensic scientist’s conclusions. To maximize the evidential value of GSR evidence, detection methods exploiting modern advancements in instrumentation must be explored and developed. This collection of work reviews the current literature review and illustrates a trend to investigate emerging methods to enhance IGSR analysis with a wider emphasis on OGSR compounds. Combining IGSR and OGSR components increases the confidence of detecting GSR on a collected sample. Overall, the development of novel analytical methods for GSR detection, the application of ground-breaking statistical methods to interpret GSR evidence using artificial intelligence (neural networks) and likelihood ratios to estimate the weight of the evidence, and the understating of the host-guest chemistry of GSR species is anticipated to provide a needed leap of knowledge in the community

Manifestations of the Maimed: The Perception of Wounded Soldiers in the Civil War North

The Civil War produced over 350,000 permanently disabled men, in addition to millions of other types of injuries and diseases. Yet, despite the overwhelming destruction to men\u27s bodies the war also laid the foundation for a number of notable advances. These generative changes include increased collaboration between medical professionals, an estimable reputation for individual surgeons, a budding international reputation for American medicine, nursing opportunities for upper class women, a rise in volunteerism in the north, and a public acceptance of anatomical study and exhibition. For all the prolific effects of the war, however, these transformations all required one thing, the destruction of soldiers\u27 bodies. It is the purpose of this study to demonstrate that disabled bodies played an integral role of shaping how civilians and soldiers perceived the wreckage surrounding them while also allowing them to recognize the benefits of such destruction. This study also examines how surgeons, nurses, gawkers, and museum goers drew personal connections with broken bodies within nineteenth-century perceptions of ability and disability

Venting in the comparative study of flexural ultrasonic transducers to improve resilience at elevated environmental pressure levels

The classical form of a flexural ultrasonic transducer is a piezoelectric ceramic disc bonded to a circular metallic membrane. This ceramic induces vibration modes of the membrane for the generation and detection of ultrasound. The transducer has been popular for proximity sensing and metrology, particularly for industrial applications at ambient pressures around 1 bar. The classical flexural ultrasonic transducer is not designed for operation at elevated pressures, such as those associated with natural gas transportation or petrochemical processes. It is reliant on a rear seal which forms an internal air cavity, making the transducer susceptible to deformation through pressure imbalance. The application potential of the classical transducer is therefore severely limited. In this study, a venting strategy which balances the pressure between the internal transducer structure and the external environment is studied through experimental methods including electrical impedance analysis and pitch-catch ultrasound measurement. The vented transducer is compared with a commercial equivalent in air towards 90 bar. Venting is shown to be viable for a new generation of low cost and robust industrial ultrasonic transducers, suitable for operation at high environmental pressure levels

Lockheed/Georgia Tech Cooperative VLSI Program

Issued as Monthly letter reports, nos. 1-9, Project no. E-21-640 (subproject B-10-601

Wideband electromagnetic dynamic acoustic transducer as a standard acoustic source for air-coupled ultrasonic sensors

To experimentally study the characteristics of ultrasonic sensors, a wideband air-coupled ultrasonic transducer, wideband electromagnetic dynamic acoustic transducer (WEMDAT), is designed and fabricated. Characterisation methods, including electrical impedance analysis, laser Doppler vibrometry and pressure-field microphone measurement, are used to examine the performance of the WEMDAT, which have shown that the transducer has a wide bandwidth ranging approximately from 47 kHz to 145 kHz and a good directivity with a beam angle of around 20˚ with no evident side lobes. A 40 kHz commercial flexural ultrasonic transducer (FUT) is then taken as an example to receive ultrasonic waves in a pitch-catch configuration to evaluate the performance of the WEMDAT as an acoustic source. Experiment results have demonstrated that the WEMDAT can maintain the most of the frequency content of a 5 cycle 40 kHz tone burst electric signal and convert it into an ultrasonic wave for studying the dynamic characteristic and the directivity pattern of the ultrasonic receiver. A comparison of the dynamic characteristics between the transmitting and the receiving processes of the same FUT reveals that the FUT has a wider bandwidth when operating as an ultrasonic receiver than operating as a transmitter, which indicates that it is necessary to quantitatively investigate the receiving process of an ultrasonic transducer, demonstrating a huge potential of the WEMDAT serving as a standard acoustic source for ultrasonic sensors for various air-coupled ultrasonic applications

The influence of air pressure on the dynamics of flexural ultrasonic transducers

The flexural ultrasonic transducer comprises a piezoelectric ceramic disc bonded to a membrane. The vibrations of the piezoelectric ceramic disc induce flexural modes in the membrane, producing ultrasound waves. The transducer is principally utilized for proximity or flow measurement, designed for operation at atmospheric pressure conditions. However, there is rapidly growing industrial demand for the flexural ultrasonic transducer in applications including water metering or in petrochemical plants where the pressure levels of the gas or liquid environment can approach 100 bar. In this study, characterization methods including electrical impedance analysis and pitch-catch ultrasound measurement are employed to demonstrate the dynamic performance of flexural ultrasonic transducers in air at elevated pressures approaching 100 bar. Measurement principles are discussed, in addition to modifications to the transducer design for ensuring resilience at increasing air pressure levels. The results highlight the importance of controlling the parameters of the measurement environment and show that although the conventional design of flexural ultrasonic transducer can exhibit functionality towards 100 bar, its dynamic performance is unsuitable for accurate ultrasound measurement. It is anticipated that this research will initiate new developments in ultrasound measurement systems for fluid environments at elevated pressures

The Whig idea of Europe, 1685-1705

This thesis analyses the Whig idea of Europe in the later 17th century, which claimed that Europe’s confessional divide should be the central fact of English foreign and domestic policy. This idea contextualised events like the Nine Years’ War (1688-1697) in a timeless Manichean divide between Catholicism and Protestantism. Those studied here argued that the Tories and the anti-Standing Army Whigs contributed to the triumph of enemies like Louis XIV, by furthering narratives that were distractions from the central European divide. Instead of focusing on canonical Whig politicians, this thesis analyses the idea of Europe by reconstructing the print networks of those who communicated it. It does so by tracing factors like citations, advertisements, and court patronage. The thesis demonstrates how a heterodox coalition of magnates, MPs, poets, clergy, pamphleteers, and others, were drawn together by an idea that became a standard rhetorical device throughout the long eighteenth century

Measurement using flexural ultrasonic transducers in high pressure environments

The flexural ultrasonic transducer comprises a metallic membrane to which an active element such as a piezoelectric ceramic is attached. The normal modes of the membrane are exploited to generate and receive the desired ultrasonic wave. Flexural ultrasonic transducers are popular due to their ability to couple to different media without requiring matching layers. There is growing demand for ultrasound measurement using flexural ultrasonic transducers in high pressure environments, such as in gas metering. However, their sealing increases the risk of transducer deformation as the pressure level is raised, due to pressure imbalance between the internal cavity of the transducer and the external environment. In this study, a novel form of flexural ultrasonic transducer for operation in high pressure environments, those above 100 bar, is shown alongside key measurement strategies. Different methods can be used to enable pressure equalization between the internal cavity and the external environment, one of which is venting and used in this study. Dynamic performance is monitored via pitch-catch ultrasound measurement in air up to 130 bar. The results suggest the suitability of the vented transducer for operation in high pressure environments compared to the classical flexural ultrasonic transducer, constituting a significant development in ultrasonic measurement

Why cuckoos remove host eggs: Biting eggs facilitates faster parasitic egg‐laying

Brood parasitism by cuckoos relies on manipulating hosts to raise their offspring and has evolved stunning adaptations to aid in their deception. The fact that cuckoos usually but not always, remove one or two host eggs while laying their eggs has been a longstanding focus of intensive research. However, the benefit of this behavior remains elusive. Moreover, the recently proposed help delivery hypothesis, predicting that egg removal by cuckoos may decrease the egg‐laying duration in the parasitism process caused by biting action, lacks experimental verification. Therefore, in this study, we examined the effects of egg removal/biting on the egg‐laying speed in the common cuckoo (Cuculus canorus) to experimentally test this hypothesis. We compared the duration of cuckoo egg‐laying in empty nests, nests with host eggs, and nests with artificial blue stick models to test whether cuckoos biting an egg/stick can significantly hasten the egg‐laying speed than no biting action. Our results showed that biting an egg or an object is associated with cuckoos laying approximately 37% faster than when they do not bite an egg or an object. This study provides the first experimental evidence for the help delivery hypothesis and demonstrates that when cuckoos bite eggs or other objects in the nest, they lay eggs more quickly and thereby avoid suffering the hosts' injurious attack

Aquaporins influence seed dormancy and germination in response to stress

Aquaporins influence water flow in plants, yet little is known of their involvement in the water‐driven process of seed germination. We therefore investigated their role in seeds in the laboratory and under field and global warming conditions. We mapped the expression of tonoplast intrinsic proteins (TIPs) during dormancy cycling and during germination under normal and water stress conditions. We found that the two key tonoplast aquaporins, TIP3;1 and TIP3;2, which have previously been implicated in water or solute transport, respectively, act antagonistically to modulate the response to abscisic acid, with TIP3;1 being a positive and TIP3;2 a negative regulator. A third isoform, TIP4;1, which is normally expressed upon completion of germination, was found to play an earlier role during water stress. Seed TIPs also contribute to the regulation of depth of primary dormancy and differences in the induction of secondary dormancy during dormancy cycling. Protein and gene expression during annual cycling under field conditions and a global warming scenario further illustrate this role. We propose that the different responses of the seed TIP contribute to mechanisms that influence dormancy status and the timing of germination under variable soil conditions