Dissertations / Theses on the topic 'Latent fingerprints'
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Beresford, Ann Louise. "The electrochromic enhancement of latent fingerprints on metal surfaces." Thesis, University of Leicester, 2013. http://hdl.handle.net/2381/28169.
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Fingerprints are unique to individuals and have been used as a method of identification in criminal investigations since the late nineteenth century. The majority of fingerprints are latent, i.e. non-visible, and require enhancement for their visualisation. Although many methods have been developed for this purpose, the recovery rate in the form of a useable print, is still disappointingly low for metallic surfaces, especially from discharged cartridges. This work aimed to explore the application of a new technique to utilise the insulating properties of fingerprint deposits, on a range of metallic surfaces. Fingerprint residue can ‘mask’ the surface preventing the electrochemical deposition of a reagent on the bare surface. Here, this takes the form of two different electrochromic polymers, polyaniline and poly-3,4-ethylenedioxythiophene, to produce a negative image of the print. Fingerprint samples were subjected to diverse environments for a range of time intervals. The enhancements were graded on a five point scale devised by Bandey, where prints graded 0-2 are considered unusable and prints graded 3-4 are usable for identification purposes. Using this scale the technique was assessed in a comparative study with existing methods (powder dusting, wet powder and superglue fuming). The outcomes identified superglue fuming as least effective and poly-3,4-ethylenedioxythiophene to be the material of choice when an sample’s history was unknown. Exploitation of the polymer’s electrochromic properties (oxidation/reduction via applied electric potential), to optimise contrast between print and substrate, resulted in the upgrading (from unusable to useable) of 16 % of samples. Project objectives were achieved; the technique was applied to challenging surfaces via the progression from model substrates to alloys to evidentially viable items. Latent fingerprints were enhanced on stainless steel, nickel plated brass, copper, lead and most importantly previously fired brass cartridges.
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Dean, Kristina. "Degradability of both a physical latent fingerprint and its associated extracted DNA." [Cedar City, Utah] : Southern Utah University, 2009. http://unicorn.li.suu.edu/ScholarArchive/ForensicScience/DeanKristina.pdf.
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Bell, Duncan J. "Improving the matching of latent fingerprints on tightly curved surfaces using stereopsis." Thesis, University of Sheffield, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.540935.
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Costa, Catia. "Development of a confirmatory test for cocaine and metabolites in latent fingerprints." Thesis, University of Surrey, 2017. http://epubs.surrey.ac.uk/813889/.
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This thesis investigates the possibility of using ambient ionisation and surface mass spectrometry for the detection and quantification of drugs of abuse in latent fingerprints. The use of fingerprints for drug testing in lieu of blood, oral fluid or urine reduces the biological hazard associated with these types of samples. The sample collection procedure is non-invasive, can be monitored to prevent cheating (submitting samples from a drug free individual) and the identity of the donor is embedded in the fingerprint ridge detail. In this thesis, three techniques – desorption electrospray ionisation (DESI), liquid extraction surface analysis (LESA) and paper spray mass spectrometry, were evaluated for their ability to provide a rapid drug test from a fingerprint. Paper spray-mass spectrometry was chosen for further development due to the ease of set-up, rapid nature of the analysis and potential to provide quantitative results. The final optimised method included full scan mass spectrometry measurements (quantitative) followed by tandem mass spectrometry (MS/MS) scans (qualitative) for the detection of cocaine, benzoylecgonine (BZE) and ecgonine methyl ester (EME). Limits of detection (LOD) were calculated to be 1 ng/mL, 2 ng/mL and 31 ng/mL for cocaine, BZE and EME, respectively. Using the optimised method of analysis, 159 individual fingerprint samples (collected from individuals seeking treatment for substance abuse) were analysed with a 99% true positive rate through the detection of either cocaine, BZE or EME. The detection of these substances was corroborated by a positive oral fluid result from samples collected from the same individuals. Analysis of fingerprint samples collected from the non-drug users (n=80) indicated < 2.5% false positive rate. The significance of detecting the parent drug or metabolite in fingerprint samples was determined through the analysis of samples after contact with seized cocaine from Forensic Science Ireland. Cocaine, BZE and EME were found in fingerprints produced by contact, showing that the presence of a cocaine metabolite in a fingerprint is not enough to show that a suspect has taken a drug. Furthermore, secondary transfer scenarios showed that cocaine could be transferred through handshakes. None of the hand cleaning methods employed in this research were sufficient to remove all traces of cocaine from contact residues. iii Finally, the possibility of visualising the fingerprint ridge detail prior to analysis was tested and the presence of the analytes was qualitatively confirmed in fingerprint samples after application of silver nitrate. This is an important step that allows for sample traceability, whilst still providing high throughput analysis and sensitivity.
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Putra, Saesario Laksmana. "Recovery of fresh latent fingerprints on black clothing fabrics using Lumicyano™." Thesis, Putra, Saesario Laksmana (2018) Recovery of fresh latent fingerprints on black clothing fabrics using Lumicyano™. Masters by Coursework thesis, Murdoch University, 2018. https://researchrepository.murdoch.edu.au/id/eprint/41512/.
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The importance of fingerprint evidence cannot be underestimated as it can provide valuable information pertaining to perpetrator of a crime. However, there is no recognised method for the enhancement of latent fingerprints on clothing fabrics. As a result, forensic laboratories rarely attempt to recover fingerprints from such substrates. Recently, new cyanoacrylate (CA) products such as Lumicyano™ have been developed. This method incorporates a fluorescent staining dye powder 3-chloro-6-ethoxy-1,2,4,5-tetrazine (C₄H₅ClN₄O) and liquid ethyl CA into a solution. Therefore, Lumicyano™ can develop fluorescent fingerprints in a one-stage fuming process without the need for an additional visualisation method apart from Forensic Light Source (FLS). The integration of fluorescent dye and CA into a mixture suggests that the fluorescent dye would selectively adhere to the polycyanoacrylate formed on the friction ridges of fingerprints. The readily visible fingerprints and the removal of the post-processing method indicate that Lumicyano™ could potentially be used on fabrics. Thus, this preliminary study aimed at assessing the efficacy of Lumicyano™ on recovering fresh latent fingerprints on black clothing fabrics. This was achieved by developing fresh latent fingerprints deposited on four different types of black clothing fabric materials; polyester, cotton, poly cotton, and nylon. The results showed that Lumicyano™ is an effective method to develop fresh latent fingerprints on black clothing fabrics. Furthermore, an indirect comparison between Lumicyano™ and silver VMD results obtained from another study was performed. The results suggest that Lumicyano™ is a better enhancement method to enhance fingerprints on black polyester and poly cotton fabrics than silver VMD. The fibre material, thread count, weave pattern of the clothing fabrics, and the fingerprint donor were proven to be important in determining the quality of the developed prints.
Keywords: Forensic science, Fingerprint evidence, Lumicyano™, Fabric.
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Mumbo, Agatha Nyanduko. "The detection and recovery of latent fingerprints on clothing and fabric items." Thesis, Mumbo, Agatha Nyanduko (2019) The detection and recovery of latent fingerprints on clothing and fabric items. Masters by Coursework thesis, Murdoch University, 2019. https://researchrepository.murdoch.edu.au/id/eprint/53939/.
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Fingermarks recovered on fabrics from a crime scene can support the three aspects of forensic investigations; identification of the individuals involved and their association to each other and assist in reconstruction of the sequence of events. Currently, there are no recognized and generally accepted methods for the enhancement of fingerprints on fabrics due to the nature of the fabric composition.
Cyanoacrylate fuming has been utilized in studies in fingerprint recovery on fabric. This method has proven to be effective for developing latent fingerprints on dark colored fabrics. On light-colored fabrics, the desired contrast isn't achieved as the CA developed prints appear as a whitish deposit. Post-treatment of CA fumed prints with fluorescent dye staining may improve the contrast, but it causes excessive background staining on the fabrics to surface.
Cyanoacrylate fuming followed by Fourier transform infrared spectroscopy (CAF/FT-IR) has been proven to be the most successful method in enhancing finger-marks on smooth and shiny fabrics like silk, polyester, and nylon. However, the technique has drawbacks; time-consuming and the CA monomer selectively polymerized onto the friction ridges of the fingerprint on some fabrics but the challenges raised from obtaining contrast of prints developed on light-colored and pattern fabrics.
Vacuum metal deposition has been utilized in studies in fingermark recovery on fabrics. Gold/zinc VMD developed fingermarks with great ridge detail on smooth and non-porous fabrics such as nylon whereas on rough and porous fabrics such as cotton, empty prints, and impression, rather than ridge details were visible. Silver VMD proved to be effective on polyester as it developed high-quality fingermarks that were attributed to the smooth, shiny and less porous tight weave of the fabric which helped retain the fingermark deposit. Silver VMD has proven to be effective for developing latent fingermarks on dark-colored fabrics and has an advantage over gold/zinc VMD in that marks visualized are light in color which contrasts well against the dark background, allows for assessment of the manner in which the fabric was touched, either by grab or press method and enables acquisition of touch DNA for identification purposes.
One step fluorescent cyanoacrylate, Lumicyano™ has proven to be effective in developing fresh latent fingermarks on dark-colored clothing fabrics. High-quality fingermarks were obtained on synthetic fabrics (polyester and nylon) than natural fabric (cotton and polycotton). This is attributed to the less absorbent (more hydrophobic) nature of synthetic fabrics than natural fabrics, thus the fingerprint residues would remain on the surface of the synthetic fabric for a longer period.
The aim of these studies was to investigate the effect of donor, fabric type, mark age and method of fingermark deposition on the quality of marks visualized using silver VMD, Lumicyano™, gold/zinc VMD, CAF & FT-IR, and CAF & iron oxide/carbon powder suspensions.
KEYWORDS
Vacuum metal deposition (VMD), Cyanoacrylate fuming (CAF), Lumicyano ™, Fingermarks, Fingermark enhancement, Fabrics, Palmar flexion creases, and Ridge detail
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Davis, Lloyd W. L. "Novel techniques for the development of latent fingermarks." Thesis, Loughborough University, 2017. https://dspace.lboro.ac.uk/2134/32218.
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The scientific study of fingerprints/fingermarks—dactyloscopy—is one of the most important fields in forensic science today. Fingermarks are amongst the most common type of evidence recovered from crime scenes and are arguably the most valued due to the fact that they are, unlike deoxyribonucleic acid (DNA), completely unique to an individual. Fingermarks recovery techniques are constantly evolving and new reagents are always being sought. This project aims to develop and access new fingermark enhancement procedures. The efficacy of an ethanoic solution of phosphomolybdic acid, has been investigated as a latent fingermark enhancement reagent, primarily on porous substrates. After treating samples and exposing them to ultraviolet radiation, the phosphomolybdic acid solution was shown to develop fingermarks to a high quality. Unlike the common amino acid reagents used for the enhancement of fingermarks on porous substrates, ninhydrin and 1,8-diazafluoren-9-one, phosphomolybdic acid stains a range of other compounds found within fingermark deposits, including lipids. The lysochrome diazo dye Oil Red O was used for comparative purposes due to its application in staining some of the same components of fingermark residues that phosphomolybdic acid would be proposed for. Initial results indicate that phosphomolybdic acid is comparable to Oil Red O at developing fingermarks on porous surfaces and may also have applications on non-porous surfaces. A systematic evaluation of solvent carriers was conducted, and whilst many solvents were insufficient, others did show some potential. Primary alcohols such as ethanol, methanol and propan-1-ol all developed fingermarks with identifiable ridge detail. Attempts to mix phosphomolybdic acid with other reagents which react with different fingermark constituents than those phosphomolybdic acid targets were, for the most part unsuccessful. However, not entirely ruled out. Many substrates were tested to observe which developed fingermarks when treated with the phosphomolybdic acid solution. Whilst marks were detected on numerous substrates, paper proved to be the most receptive. Similar stains to the phosphomolybdic acid were tested under the same conditions, however, none were as effective as the phosphomolybdic acid. A non-destructive, non-invasive technique was developed, utilising cuprous metals and their reactions with rubeanic acid. By bringing substrates with fingermarks deposited upon their surface into contact with a copper or copper alloyed plate, it was possible to transfer the fingermark residues to the plate. Forensic gelatin lifters could then be used to lift the marks from the metal plates, these lifted marks could subsequently be treated with a rubeanic acid solution to visualise the fingermarks. The rubeanic acid reacted with the Cu(II) which had been transferred to the fingermark residues to produce a dark product in the pattern of fingermark ridges. The technique was successful at developing fingerprints on semi-porous substrates. The technique was as effective on non-porous substrates, such as glass, but an investigation into the process on porous surfaces was less positive. Attempts to reuse the cuprous metals for the transference of fingermarks after an initial lift resulted in double or ghosted marks being developed, after a thorough wash with soap and water. This was overcome by cleaning with the metal cleaner Brasso. Copper cleaned with Brasso was reused 5 times to show its effectiveness, and adverse effects were minimal. The UK s recent move to polymer banknotes has seen some of the currently used fingermark enhancement techniques for currency potentially become redundant, due to the substrate characteristics of the polymer surfaces. Possessing a non-porous surface with some semi-porous properties, alternate processes are required for polymer banknotes. A preliminary investigation was conducted in to the recovery of fingermarks from polymer notes via vacuum metal deposition using elemental copper. The study successfully demonstrated that fresh latent fingermarks, from an individual donor, could be clearly developed and imaged in the near infrared. By varying the deposition thickness of the copper, the contrast between the fingermark minutiae and the substrate could be readily optimised. Where the deposition thickness was thin enough to be visually indistinguishable, forensic gelatin lifters could be used to lift the fingermarks. These lifts could then be treated with rubeanic acid to produce a visually distinguishable mark. The technique has shown enough promise that it could be effectively utilised on other semi- and non-porous substrates. A follow up group study was less effective than the aforementioned initial study. Many samples were processed using the vacuum metal deposition; incorporating a comparison study between copper and the gold/zinc standard and a depletion trial. However, when imaging was attempted a week after treatment, the results experienced before were unable to be replicated. Attempts to recover samples of radioactive nickel isotope from metal substrates using forensic gel lifters were initially unexceptional. Wipe tests were more successful at recovering the isotope. Experimentation using some non-metallic substrates was more fruitful, the gel lifters were able to recover the radioisotope more readily. Autoradiography showed that, although a weak beta emitter, nickel could be imaged when in sufficient quantities. By using nickel and a short half-life isotope of phosphorus in conjunction with patterned stamps and patterned deposits it was possible to image these patterns by autoradiography of the gels used to lift from the substrates these were deposited upon. These autoradiography images showed enough detail to warrant attempts with a synthetic finger, however, the imaging was insufficient to image the fine details of the friction ridges. Fingermarks deposited on the surface of agar gels showed bacterial growth after incubation for 24 hours. Aseptic transfer of bacterial colonies to fresh agar plates in a typical streak pattern were fruitful. Further transference to a nutrient broth were effective, however, attempts to seed bacterial agar plates for use in inhibition tests were unsuccessful. Overall, phosphomolybdic acid proved to be relatively effective, being able to develop fingermarks on a number of substrates. The copper transfer method, although, less fruitful than PMA showed promise. This lead to the idea of gel lifting from copper VMD treated polymer banknotes which was much more effective. Although, the radioactive and biological techniques showed promise, they were unfortunately unsuccessful at developing fingermarks. A number of the techniques evaluated and developed were successful enough to be published in forensic journals.
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Munagani, Indira Priya Darshini. "Mining Rare Features in Fingerprints using Core points and Triplet-based Features." Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/24784.
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A fingerprint matching algorithm with a novel set of matching parameters based on core points and triangular descriptors is proposed to discover rarity in fingerprints. The algorithm uses a mathematical and statistical approach to discover rare features in fingerprints which provides scientific validation for both ten-print and latent fingerprint evidence. A feature is considered rare if it is statistically uncommon; that is, the rare feature should be unique among N (N>100) randomly sampled prints. A rare feature in a fingerprint has higher discriminatory power when it is identified in a print (latent or otherwise). In the case of latent fingerprint matching, the enhanced discriminatory power from the rare features can help in delivering a confident court judgment. In addition to mining the rare features, a parallel algorithm for fingerprint matching on GPUs is also proposed to reduce the run-time of fingerprint matching on larger databases. Results show that 1) matching algorithm is useful in eliminating false matches. 2) each of the 30 fingerprints randomly selected to mine rare features have a small set of highly distinctive statistically rare features some of whose occurrence is one in 1000 fingerprints. 3) the parallel algorithm implemented on GPUs for larger databases is around 40 times faster than the sequential algorithm.Master of Science
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Reip, Alexander. "Studies on the synthesis and use of rare earth doped nanophosphors for application on latent fingerprints." Thesis, Brunel University, 2015. http://bura.brunel.ac.uk/handle/2438/11626.
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Nanotechnology has been increasingly employed in forensic science for the detection of latent fingerprints, using multiple techniques from new aluminium nanomaterials for dusting to quantum dot dispersions, to try to increase and enhance areas where prints are likely to be found at scenes of crime. Different substrates use a diverse range of methods to develop prints when they are found and each method has its own drawbacks. It is not viable to use many of these techniques in conditions other than in a laboratory due to the harmful environmental effects they can cause over long term use. With this in mind a new easier to use technique that can be used on any substrate from wood to glass to paper was looked into. A range of nano-sized rare earth phosphor precursors were synthesised using homogeneous precipitation and solid state methods which were then converted to phosphors by firing at 980oC. Eu3+ and Tb3+ doped Y2O3, YVO4 and Y2O2S were chosen for their luminescent intensity. Analysis of each of the phosphors was carried out using multiple techniques and a single host lattice chosen for continuation. Y2O3:Eu3+ and Y2O3:Tb3+ were coated using a modified Stöber process to try and decrease the agglomeration of particles as well as allowing for surface modification to take place. Modifications of the surface were prepared and analysed, and these particles were then used in multiple fingerprint examinations to examine the adherence on fingerprints of different ages. The surface modifications manifested great adherence to the fingerprint residue even after two weeks elapsed and showed great promise after a two year period.
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Yi, Renee. "Novel powder methods for the visualization of latent fingerprints: The case for tumeric and other spices." Thesis, Yi, Renee (2018) Novel powder methods for the visualization of latent fingerprints: The case for tumeric and other spices. Masters by Coursework thesis, Murdoch University, 2018. https://researchrepository.murdoch.edu.au/id/eprint/41444/.
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Human fingerprint is such an unique human identity that differ from person to person. Even a twin also don’t have an identical fingerprint. In a forensic investigation, the fingerprint is one of the most common evidence that can be found and considered valuable. It enables the possible identification of the person of interest in a criminal case. A latent fingerprint is an invisible fingerprint that maybe encountered in a crime scene. The process of enhancement is necessary for the latent fingerprint to be observed by naked eyes. Thus, it is an important process. The important consideration for the development of latent fingerprint is non-destructive to the evidence itself and the method is simple, easy and safe to the examiner.
Powdering method is one of the most common and traditional method been used since the 19th century. The principle of the powdering method is adhesion of the powder particles towards the natural residues that found on a latent fingerprint. Previously, researchers used different materials as fingerprint powder used during powdering but limitations were found. Some of the materials are toxic and endanger human health. Besides this, some of the fingerprint powders do not provide sufficient contrast and sufficient details of the fingerprint after enhancement. Thus, this literature review aims to critically assess the current literature that related to the use of novel powders such as spices – (eg. Turmeric) in the development of a latent fingerprints. The method of latent fingerprint developed by turmeric powder will be performed again to verify the result of previous research. Furthermore, due to currently there are no studies that have investigated the use of other novel powders such as cinnamon and paprika in latent fingerprint development, this literature review will also explore the chemical composition of both spices in order to assess the potential for new natural fingerprint powder in future.
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Hoyle, Kevin. "Minutiae Triplet-based Features with Extended Ridge Information for Determining Sufficiency in Fingerprints." Thesis, Virginia Tech, 2011. http://hdl.handle.net/10919/34010.
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In order to deliver statistical and qualitative backing to latent fingerprint evidence, algorithms are proposed (1) to perform fingerprint matching to aid in quality assessment, and (2) to discover statistically rare features or patterns in fingerprints. These features would help establish an objective minimum-quality baseline for latent prints as well as aid in the latent examination process in making a matching comparison. The proposed methodologies use minutiae triplet-based features in a hierarchical fashion, where not only minutia points are used, but ridge information is used to help establish relations between minutiae. Results show (1) that our triplet-based descriptor is useful in eliminating false matches in the matching algorithm, and (2) that a set of distinctive features can be found that have sufficient discriminatory power to aid in quality
assessment.Master of Science
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Ya, Adelaide. "The detection and enhancement of latent fingerprints present on the adhesive side of black or dark coloured adhesive tapes." Thesis, Ya, Adelaide (2018) The detection and enhancement of latent fingerprints present on the adhesive side of black or dark coloured adhesive tapes. Masters by Coursework thesis, Murdoch University, 2018. https://researchrepository.murdoch.edu.au/id/eprint/41443/.
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Duct tapes and other similar adhesive tapes are often encountered in various types of crime scenes and these range from homicides involving tape-bound bodies to construction of improvised explosive devices. Therefore, the ability to obtain quality fingerprint impressions that may be present from the adhesive side of tapes can yield critical investigative information aiding in the investigation process. The process of recovering the latent fingerprints on the adhesive side of tapes, however, can be problematic due to the nature of the adhesive surface.
It has been observed that there are a number of techniques that have been researched and proven to be able to develop quality latent fingerprint located on the adhesive side of tapes and cyanoacrylate fuming was one of them. However, the use of post-treatment fluorescent dyes has been considered as a potential risk to the health of frequent users. Therefore, the objective of this literature review was to evaluate those techniques available to better understand how the use of a one-step cyanoacrylate fuming technique might be an alternative and superior technique. In addition, as the research on utilising of a one-step cyanoacrylate fuming method has not been done on adhesive surfaces previously, this literature review provides an additional supporting reason for the present proposed research to evaluate the effectiveness of the method in retrieving latent fingerprints.
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Hildebrandt, Mario Verfasser], and Jana [Gutachter] [Dittmann. "On digitized forensics : novel acquisition and analysis techniques for latent fingerprints based on signal porcessing and pattern recognition / Mario Hildebrandt ; Gutachter: Jana Dittmann." Magdeburg : Universitätsbibliothek Otto-von-Guericke-Universität, 2020. http://d-nb.info/1220830143/34.
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Van, Der Spil Krystal. "Evaluating the efficiency and sensitivity of one-step cyanoacrylate fuming methods in the detection and visualisation of latent fingerprints on the adhesive side of tape." Thesis, Van Der Spil, Krystal (2019) Evaluating the efficiency and sensitivity of one-step cyanoacrylate fuming methods in the detection and visualisation of latent fingerprints on the adhesive side of tape. Masters by Coursework thesis, Murdoch University, 2019. https://researchrepository.murdoch.edu.au/id/eprint/46924/.
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The evidential value of adhesive tape recovered from a crime scene plays a critical role in the criminal investigation as it could potentially contain things such as fibres, hair, DNA evidence, or fingerprints. Adhesive tape is a ubiquitous material that can be used in crimes that involve kidnapping and murder, as well as used to house cables in acts of terrorism. With regards to the adhesive side of tape, the sticky nature of this surface not only increases the likelihood of latent fingerprint deposits but has routinely proved to be a problematic substrate to work with. As latent fingerprints are generally invisible to the eye, enhancement methods are required to conduct adequate analysis on the fingerprint details. Despite several methods of fingerprint enhancement available, common issues including high background staining and low selectivity of fingerprint deposits create a difficult problem for forensic investigators to solve. Studies have shown that these issues can be overcome by utilising aqueous solutions of fingerprint powders, as well as traditional dye methods like gentian violet. Fluorescent dyes have also been explored and shown to be very effective when used on darker-coloured adhesive tapes. With regards to aged latent fingerprints, sticky-side powder and phase transfer catalysts have proven to be viable methods of detection and development. Traditional cyanoacrylate fuming was observed to be the best method of development in all reviewed cases, but the requirement of subsequent dye staining poses potential health issues to the user and the environment. One-step cyanoacrylate fuming has been proposed as a method incorporating the staining step into the cyanoacrylate fuming step, thus completing both steps simultaneously. As one-step cyanoacrylate fuming is a relatively new method of development, its potential application to the development of latent fingerprints on the adhesive side of tape has not been explored to its full extent and should be researched more extensively.
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Merkel, Ronny [Verfasser], and Jana [Akademischer Betreuer] Dittmann. "New solutions for an old challenge : chances and limitations of optical, non-invasive acquisition and digital processing techniques for the age estimation of latent fingerprints / Ronny Merkel. Betreuer: Jana Dittmann." Magdeburg : Universitätsbibliothek, 2014. http://d-nb.info/1054638985/34.
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Johnson, George Anthony. "Luminescence studies of latent fingerprint residue." Thesis, University of East Anglia, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.257556.
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Shah, Bansi C. "Novel fingerprint development techniques." Thesis, Loughborough University, 2013. https://dspace.lboro.ac.uk/2134/12533.
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There are numerous pre-existing fingerprint development techniques, however, often prints are difficult to develop, depending on their age or the surface upon which they have been deposited. Forensic scientists are relentlessly looking for new and better methods to enhance fingerprints. More recent technologies have higher sensitivity to very low levels of constituents present in residues and so are able to unearth significant details from a person's fingerprints at molecular level e.g. DNA, drug metabolites. Therefore, research continues in an attempt to generate novel, nondestructive processes that can enhance latent fingerprints. Exposing fingerprints to the p-block compounds selenium dioxide (SeO2), phosphorus sulfides (P4Sx) and phosphonitrilic chloride trimer (NPCl2)3, in the vapour phase resulted in latent prints being visualized on a range of media. Selenium dioxide revealed prints on metal surfaces (e.g. brass) which were enhanced further upon formation of a dark brown coating of copper-selenide formed on the surface when exposed to moisture, giving a better contrast. P4S3 vapour revealed a higher percentage of prints and samples had greater stability in air while although (NPCl2)3 was able to develop fingerprints, the low quality was undesirable. Initially it was thought that (NPCl2)3 has the potential for further derivatisation but was proven very difficult to interact with compounds especially those with the potential to induce fluorescence. However, all three compounds are commercially available and sublimation techniques are straightforward.
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Coulston, Jodie Louise. "Nucleation and growth phenomena of silver in physical developer for latent fingerprint visualisation." Thesis, University of Leicester, 2018. http://hdl.handle.net/2381/42812.
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Fingerprints are used to identify individuals in both criminal and civil cases based on their unique pattern of characteristic ridge details. Latent, i.e. non-visible, fingerprints are the most commonly exploited type of fingermark, since they are frequently left at a crime scene. However, they must be visualised via an enhancement method, the nature of which is dependent on the substrate. Physical developer (PD) is a widely used effective chemical enhancement method for the visualisation of fingerprints on porous surfaces, notably paper. The principle of the technique is based on a ferrous/ferric redox couple reducing silver ions to colloidal silver metal, which is stabilised by a surfactant formulation. Recent environmental legislation banning a crucial surfactant component – Synperonic N – motivates the design of a new formulation. This requires determination of the mechanism of the PD process and the roles of the components; previous work is macroscopic and empirical. This thesis describes solution and interfacial measurements and surface imaging that provide mechanistic insights and real-time dynamics of the process. Dynamic light scattering and microscopy reveal the particle size in solution. These particles deposit selectively on the fingermark, interacting with chemical constituents identified via spot tests, and grow to a size over an order of magnitude greater than in solution. Silver nucleation and growth on the surface are independent of the age of the mark. Neutron reflectivity measurements revealed that the cationic surfactant component, n-dodecylamine acetate, adsorbs more strongly to a silver surface in the presence of a non-ionic surfactant. Working solution stability variations with surfactant formulation are characterised, together with the effect on latent mark development times. The mechanistic and structural insights are used to design an alternative PD formulation with greater stability at no loss of the image quality.
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Siah, Jasmine. "Identification of the optimum latent fingerprint recovery method from pig skin at varying temperatures." Thesis, Siah, Jasmine (2020) Identification of the optimum latent fingerprint recovery method from pig skin at varying temperatures. Masters by Research thesis, Murdoch University, 2020. https://researchrepository.murdoch.edu.au/id/eprint/61770/.
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Successful development of latent fingerprints in criminal investigations can be extremely beneficial in solving cases. Many studies have been undertaken to identify the most effective method for the recovery of latent fingerprints from various surfaces and it was determined that human skin is one of the most difficult surfaces for fingerprints development. However, it is desirable for investigators to obtain latent fingerprints from human skin as physical contact between perpetrators and victims are very common. In light of that, researchers have tested different methods such as alternative light sources, dactyloscopic powders, chemicals, direct transfer and more on skin and have been successful but not without challenges. Factors such as normal body functions, skin conditions, environmental conditions, post-deposition conditions and environmental contaminants can all affect the durability of latent fingerprints and the recovery rate. Hence, results may vary in terms of efficacy in different cases, conditions and countries where many of these factors are different. In cases where fingerprints are smudged or distorted, sweat residue in treated latent fingerprints may be used for DNA recovery which if treated properly can generate DNA profile of person of interest. Nonetheless, some latent print enhancement techniques provide more hindrance to the DNA recovery process than others. This paper presents a comparative analysis on the different recovery techniques tested for the development of latent fingerprints on skin and the overview of how the many challenges affect the durability of latent fingerprints and success rate of recovery.
Keywords: latent fingerprints, human skin, powdering methods, chemical methods, DNA
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Radspinner, David Andrew 1965. "Developments in atomic analysis and imaging utilizing scientific charge-transfer devices: Axial viewing of the inductively coupled plasma, advanced hollow cathode designs, and latent fingerprint imaging." Diss., The University of Arizona, 1997. http://hdl.handle.net/10150/282524.
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This document describes the development of spectroscopic techniques which benefit from the use of charge-transfer devices. Both charge-coupled devices (CCD's) and charge-injection devices (CID's) are used in the techniques presented here such as atomic emission spectroscopy and latent fingerprint imaging. The use of a CID echelle system for axial viewing of the inductively coupled plasma (ICP) demonstrates the enhancement in sensitivity that can be obtained over tangential viewing. More importantly though, are the advantages afforded by simultaneous multi-element detection. Axial viewing of the ICP has shown to not only improve upon the detection limits of several metals by, in some cases, a half order of magnitude, but also to increase the amount of light collected and thus reduce the time of analysis. Along with this, the effect of interferences upon the detection of various metals is, at worst, equivalent to that of an ICP with tangential viewing. Further enhancement of sensitivity in atomic analysis can be achieved by atomic fluorescence with an ICP. Although in the past, hollow cathode lamps have proven to be insufficient, advanced designs of hollow cathode lamps presented here have demonstrated an increase in the intensity of lines of copper best suited for use in ICP atomic fluorescence. Lastly, a latent fingerprint has been imaged with the use of a scientific CCD and a flashlight where in the past such a technique was accomplished with high power lasers. By using a CCD, the immediate digitization of information combined with the sensitivity and image processing capabilities offer a portable means by which to image latent fingerprints on poor surfaces.
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Resende, Raquel Vaz. "EXTRAÇÃO DE DNA DE IMPRESSÕES DIGITAIS LATENTES DEPOSITADAS EM DIFERENTES SUPORTES E REVELADAS COM NINIDRINA E PÓ PRETO." Pontifícia Universidade Católica de Goiás, 2013. http://localhost:8080/tede/handle/tede/2367.
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Previous issue date: 2013-02-08The importance of scientific proof for the current Brazilian justice system is notorious. Article 158 of the CPC provides that when the offense is a trace essential examination of the corpus delicti. But many fingerprints arriving in section showdown Police Technician - Scientific Goiás, do not present conditions for analysis are blurred or incomplete, and thus unusable. The possibility of extracting DNA of these appears as an option in criminal investigations. The present study detected by light microscopy, scaly epidermal cells in 98% of the fifty sheets containing fingerprints subjected to Leishman stain, and the amount varied from fifteen to seven hundred and seventy cells per slide. After DNA extraction sixty-nine samples, deposited on five different media (aluminum, wood, paper, plastic and glass) were obtained concentrations ranging from 0.3 ng / uL to 25.4 ng / uL. Analyzing the concentrations of each surface separately observed that wood was the one with the highest average concentration of DNA (10.67 ng / uL), while paper and plastic had equal means and the lowest (5.92 ng / uL) . Comparing the media by student t test, we found three statistically significant analysis, the largest difference was observed between the surfaces of wood and paper (p = 0.001). When extracting DNA prints developed with ninhydrin or impregnated by black powder, concentration obtained in 70% of samples with ninhydrin and 60% of samples with dust. This study corroborates several studies have shown that it is possible to extract DNA from surfaces that have been touched by the hands of just one person. Our experiments also showed obtaining a higher concentration in the porous surfaces in relation to smooth surfaces and that using ninhydrin and black powder also allow the extraction of said genetic material.
A importância da prova científica para o atual sistema de justiça brasileiro é notória. O artigo 158 do CPP determina que quando a infração deixar vestígios será indispensável o exame do corpo de delito. Porém, muitas impressões digitais que chegam à seção de confronto da Polícia Técnico - Científica de Goiás, não apresentam condições de análises por estarem borradas ou incompletas, sendo assim, inutilizadas. A possibilidade de extrair DNA destas surge como uma opção nas investigações criminais. O presente estudo detectou, à microscopia óptica, células descamativas da epiderme em 98% das cinquenta lâminas contendo impressões digitais submetidas à coloração de Leishman, sendo que a quantidade variou de quinze a setecentos e setenta células por lâmina. Após a extração de DNA de sessenta e nove amostras, depositadas em cinco suportes diferentes (alumínio, madeira, papel, plástico e vidro) foram obtidas concentrações que variaram entre 0,3 ng/µL a 25,4 ng/µL. Analisando as concentrações de cada superfície separadamente observamos que a madeira foi a que apresentou a maior concentração média de DNA (10,67 ng/µL), enquanto que o papel e plástico apresentaram médias iguais e as menores (5,92 ng/µL). Na comparação entre os suportes pelo teste t student, encontramos três análises estatisticamente significativas, sendo a maior diferença foi observada entre as superfícies de madeira e papel (p = 0,001). Ao extrair DNA de impressões reveladas com ninidrina ou impregnadas pelo pó preto, obtivemos concentração em 70% das amostras com ninidrina e 60% das amostras analisadas com pó. O presente trabalho corrobora com vários estudos que já demonstraram ser possível extrair DNA de superfícies que foram simplesmente tocadas pelas mãos de uma pessoa. Nossos experimentos demonstraram, ainda, a obtenção de uma maior concentração nas superfícies porosas em relação às superfícies lisas e que o uso de ninidrina e pó de cor preta também permitem a extração do referido material genético.
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Єрмак, Аліна Володимирівна. "Удосконалення технології виготовлення гумових виробів на основі латексу." Магістерська робота, Київський національний університет технологій та дизайну, 2021. https://er.knutd.edu.ua/handle/123456789/19428.
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В дипломному магістерському проекті зроблено аналіз літературних джерел по виготовленню гумових виробів, аналіз вихідної сировини та матеріалів, обґрунтовано метод виробництва медичних напальчників, розроблено технологічну схему та встановлено режими виготовлення медичного напальчника. Удосконалено рецептуру латексної суміші, рекомендовано використання натурального латексу на основі каучуку марки GIVUL LA з додаванням води 4,5 мас. част. на 100 мас. част. каучуку, що дає можливість отримати медичні напальчники з покращеними фізико-механічними властивостями та дозволяє зменшити кількість умочувань з трьох до двох з міжшаровою просушкою при 70°С, вулканізацією при 115°С протягом 10 хв. при швидкісті робочого ланцюга 75 Гц. Розраховано матеріальний баланс, продуктивність та кількість обладнання. Розглянуто питання охорони праці для працівників лінії по виготовленню мочаних медичних виробів, враховано вимоги безпеки в аварійних ситуаціях та під час пожежі. В будівельному розділі розроблено генеральний план підприємства та цеха на основі розробленої схеми виробництва, транспортних і людських потоків з урахуванням об’ємно-планувальних, конструктивних рішень промислової будівлі та техніко-економічних рішень.In the master's degree project the literature sources on the manufacture of rubber products, analysis of raw materials are analyzed, the method of production of medical fingertips is substantiated, a technological scheme is developed and modes of production of medical fingertips are established. The formula of the latex mixture has been improved, the use of natural latex based on GIVUL LA rubber is recommended with the addition of 4.5 wt. part. of water per 100 wt. part. of rubber, which makes it possible to obtain medical fingertips with improved physical and mechanical properties, and reduces the number of soaks from three to two with interlayer drying at 70°C, vulcanization at 115°C for 10 min at a working chain speed of 75 Hz. Material balance, productivity and quantity of equipment are calculated. The issue of labor protection for employees of the line for the production of soaked medical products is considered, safety requirements in emergency situations and in case of fire are taken into account. In the construction section the general plan of the enterprise and shop is developed on the basis of the developed scheme of production, transport and human flows taking into account volume-planning, constructive decisions of the industrial building and technical and economic decisions.
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Yu, Yi. "Radio Resource Planning in Low Power Wide Area IoT Networks." Electronic Thesis or Diss., Paris, CNAM, 2021. http://www.theses.fr/2021CNAM1287.
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Cette thèse étudie le problème de planification des ressources pour les réseaux IoT longues portées basés sur les technologies NB-IoT et LoRa. Dans les deux cas, on suppose que les capteurs et les collecteurs sont distribués suivant des processus de points de Poisson spatial indépendants marqués par le caractère aléatoire du canal. Pour le NB-IoT, nous élaborons un modèle de dimensionnement statistique qui estime le nombre de ressources radio nécessaires en fonction du délai d’accès toléré, de la densité des nœuds actifs, des collecteurs et de la configuration de l’antenne. Pour le réseau LoRa, nous proposons une technique d’allocation de plusieurs sous-bandes pour atténuer le niveau élevé d’interférence induit par les nœuds qui transmettent avec le même facteur d’étalement. Pour allouer dynamiquement le facteur d’étalement et la puissance, nous présentons une approche d’apprentissage automatique avec multi-agents qui permet d’améliorer l’efficacité énergétiqueIn this thesis, we focus on radio resource planning issues for low power wide area networks based on NB-IoT and LoRa technologies. In both cases, the average behavior of the network is considered by assuming the sensors and the collectors are distributed according to independent random Poisson Point Process marked by the channel randomness. For the NB-IoT, we elaborate a statistical dimensioning model that estimates the number of radio resources in the network depending on the tolerated delay access, the density of active nodes, the collectors, and the antenna configuration with single and multi-user transmission. For the LoRa network, we propose a multi-sub band allocation technique to mitigate the high level of interference induced by nodes that transmit with the same spreading factor. To dynamically allocate the spreading factor and the power, we present a Q-learning multi-agent approach to improve the energy efficiency
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Yong, Siaw-Jan. "Detection of latent fingerprints with cyanoacrylates : new techniques involving coloured and photoluminescent compounds." Phd thesis, 1986. http://hdl.handle.net/1885/138856.
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Costley, Destiny. "Efforts to improve latent fingerprint impression processing using fluorescent and colored superglues." Thesis, 2014. https://hdl.handle.net/2144/14679.
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The use of cyanoacrylate (CA) as a fuming technique for the development of latent friction ridge skin impressions has been widespread for decades within the forensic lab as well as in the field at crime scenes. Important features of processing latent print impressions using this method include that it makes visible latent print impressions that for the most part cannot be seen with the unaided eye and it preserves latent print impressions for future processing/examination. The superglue fumes "fix" the latent print impression to the substrate making it difficult to wipe away, thereby decreasing the chances of destruction during packaging at the scene, transportation, and processing in the lab. One of the disadvantages to this technique is the lack of contrast between the white polymers that are formed on the latent print impression residue and light colored backgrounds on which the latent print impression may be present.
Attempts were made to develop a one-step cyanoacrylate fuming method that would enhance visualization of latent print impressions on light colored backgrounds without the need for an alternative light source, dye staining, or powdering. Latent print impressions were applied to black and white ceramic tiles, white painted wood and white/translucent textured plastic. Protein and hemoglobin stains, commercial colorants, sublimation dyes, hair dye, and printer ink were added to ethyl-CA in an attempt to create a co-polymerization process of the vaporized cyanoacrylate monomers and colorant molecules on latent print residue. Fuming was also attempted using pre-colored commercial glues with the assumption that the attached CA polymers on the latent print impression residue would retain their original color properties. None of these methods proved successful.
The practical use of a new fluorescent CA, Lumicyano^TM, was also examined. Following fuming, an ALS is utilized for the excitation of the developed latent print impressions using this technique. Strong fluorescence could not be observed on all substrates. In this particular study, fuming with traditional CA followed by the application of powder or dye stains to latent print impressions currently appears to be the most efficient technique for latent print enhancement on the white or light colored substrates used in this study.
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Hsieh, Wang-Cheng, and 謝旺成. "Thermal evaporation of ZnO and mixture of ZnO and SiO for developing latent fingerprints." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/jndt5f.
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碩士國立臺灣科技大學
材料科學與工程系
99
In this research, development of latent fingerprint can be achieved by thermal evaporation using various oxide sources and simple procedures without annealing. Results shows that latent fingerprints can be clearly developed and behave luminescence-emitting property in specific condition, which is beneficial to forensic science. Latent fingerprint can be successfully developed using ZnO, Zn(OH)2, and Zn(NO3)2, respectively. Films exhibit metallic Zn structure by XRD and showed no luminescence-emitting property by PL measurement, even proceeded by oxygen plasma. However, by changing evaporation source to amorphous SiO powder showed slightly luminescence-emitting. Furthermore, light emitting intensity became larger when films were stored in the air for 8 months. Latent fingerprint developed by source mixed of ZnO and SiO powders showed considerable luminescence intensity when firstly evaporated, which is possibly caused by defects of dioxasilirane and silylene. Finally, various of objects were selected to try to achieve development of latent fingerprint, and investigate the luminescence-emitting property as well as take pictures after excited by UV light. Results could be applied to forensic science.
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Jones, Naomi. "Metal deposition techniques for the detection and enhancement of latent fingerprints on semi-porous surfaces." 2002. http://hdl.handle.net/2100/1026.
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University of Technology, Sydney. Faculty of Science.Fingerprints can provide critical evidence in the investigation of crime. Most fingerprints are latent, or invisible, and hence need detection and enhancement before they can be used in the investigation of crime. While techniques exist for fingerprint development on a range of surfaces, the detection of prints on semi-porous substrates is particularly difficult. Vacuum metal deposition (VMO) and multi-metal deposition (MMO) were investigated for their ability to detect latent prints on such surfaces. VMD is recognised as a very sensitive method of latent print visualisation but inconsistent resu1ts are commonly encountered. This research shows that reproducible VMD development is only obtainable when the amount of gold deposited is carefully controlled. The type and quality of VMD development obtained is influenced by a number of critical factors. These factors include the amount of gold deposited, the polymer type of the surface being treated, the nature of the latent print itself, and the presence of any other contaminants on the surface (whether due to the history of the exhibit or treatment with other fingerprint reagents). MMD has not found routine application due to its complexity and mediocre results. Recent research that sought to overcome these problems resulted in the development of a new formulation known as MMDII. Several MMD formulations were trialled in this study and MMDII proved to be the superior formulation, giving better overall print detail. On non-porous surfaces, MMDII may offer further print development than that achieved with cyanoacrylate fuming (CAF) and luminescent staining, but VMD always gave superior results to MMD. Polymer banknotes are a difficult semi-porous surface, causing particular problems for fingerprint laboratories. A procedure utilising CAF followed by VMD and finally luminescent staining enables successful print development on this substrate. Success on new notes was achieved with prints up to 18 months old; unfortunately, the possibility of successful print development decreases on used banknotes. VMD has two important advantages for print visualisation on polymer notes: i) it is sensitive enough to detect the small amounts of residue remaining; and, ii) the zinc layer removes a significant amount of interference caused by the banknote design. MMD and VMD were compared to standard techniques on other semi-porous surfaces. MMD proved to be the technique of choice on these surfaces. The ability of MMD to react with print residue within and on the surface is believed to be important to its success.
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Kuo, Shih-Yu, and 郭適瑜. "Applications of Highly Fluorescent Semiconducting Polymer Dots：(1) In Vitro Detection of Lead Ions；(2) Visualization of Latent Fingerprints." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/x8v4x5.
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碩士國立中山大學
化學系研究所
103
1. Dual Colorimetric and Fluorescent Sensor Based On Semiconducting Polymer Dots for Ratiometric Detection of Lead Ions in Living Cells Recently, semiconducting polymer dots (Pdots) have become a novel type of ultrabright fluorescent probes which hold great promise in biological imaging and analytical detection. Here we developed a visual sensor based on Pdots for Pb2+ detection. We first embedded near-infrared (NIR) dyes into the matrix of poly[(9,9-dioctylfluorene)- co-2,1,3-benzothiadiazole-co-4,7-di(thiophen-2-yl)-2,1,3-benzothiadiazole] (PFBT-DBT) polymer and then capped the Pdots with polydiacetylenes (PDAs), in which parts of the PDAs were prefunctionalized with 15-crown-5 moieties to form Pdots. The high selectivity of these Pdots for lead ions is attributed to the formation of 2:1 15-crown- 5-Pb2+-carboxylate sandwich complex on the Pdot surface. After Pb2+ chelation, the conjugation system of the PDA was perturbed and strained, causing a chromatic change of the PDA from blue to red. At the same time, the encapsulated NIR dyes were liable to leach out that resulted in an emission variation of the Pdots. Accordingly, lead ions can be recognized by either color change or emission variation of the Pdots. We also loaded these nanoprobes into live HeLa cells through endocytosis, and then monitored changes in Pb2+ levels within cells, demonstrating their utility for use in cellular and bioimaging applications. In addition, we fabricated easyto-prepare test strips impregnated with Pdot-poly(vinyl alcohol) films to identify Pb2+ in real samples, which proved their applicability for in situ on-site detection. Our results suggest that this Pdot-based visual sensor shows promising potential for advanced environmental and biological applications. 2. The Detection of Latent Fingerprints on Porous/Non-Porous Surfaces Using Combination Semiconductor Polymer Dots and Ninhydrin for Colorimetric and Highly Fluorescence In the 21st century, this is vitally important in crime scene investigation for tracking the links between the scene,victims and the perpetrators.The impressions left by the friction ridge skin on the palmar surfaces of the hands, most often referred to as fingerprints, not only demonstrate contact but also are sufficiently unique to enable personal identification. So there are many fingerprint reagents on detection of laterent fingerprints. But most of them can only be used on a single material surfaces (Porous or Non-Porous).Here, we developed the new fingerprint fluorescent reagent based on Semiconducting Polymer Dots (Pdots) for detection of laterent fingerprint. This is can be used on porous surface besides non-porous. Meanwhile, the Pdots can reveal the fingerprint with high contrast fluorescence result from blue shift. The hydrophobic interactions between the Pdots and fingerprint residue play an important role in the blue shift. We combine the Pdots and Ninhydrin in order to reveal fingerprint with color. Ninhydrin is most commonly used to detect amino acid in fingermarks. When reacting with amino acid, a deep blue or purple color known as Ruhemann''s purple is produced. Ultimately fingerprints simultaneously are revealed on porous/nonporous surfaces with color and fluorescence.
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Jar, Jung-Hau, and 賈中豪. "Preparation of nano-silver physical developer and its application in developing latent fingerprints on porous and non-porous surfaces." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/97720481994215939695.
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碩士元智大學
化學工程與材料科學學系
97
Researchers of physical developer (PD) have often think about the most sensitive reagent for reacting with water-insoluble components in latent fingerprints. However, research on time needed to develop latent fingerprints on non-porous surface and how to increase shelf-life are still lacking. For traditional PD, there is a complex preparation procedure and no one has discussed the time needed for developing a latent fingerprint on wet items. Therefore, the aims of this research are to explore how to simplify the synthesis procedure, to apply a nano-silver-based PD to develop latent fingerprints on non-porous and porous surfaces, to determine the time needed for the new PD to develop latent fingerprint on wet items, and to extend the shelf-life of new PD. For the preparation of the nano-silver PD, the chemical reduction method was used. FESM was used to examine and confirm the size range of the silver particles. In addition, microscopy examination was made to explain how well silver nanoparticles adhere to different substrates. The result of this study showed the new PD is a stable suspension of nano-silver particles. Application of the new PD to develop latent fingerprints on both porous and non-porous surfaces was successful. To conclude, this study is of importance in testing the stability of a new PD and its ability to develop fresh and non-fresh latent fingerprint on both porous and non-porous surfaces in normal and special environment. A reaction mechanisms of the new PD was also proposed.
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Chen, You-Hong, and 陳宥閎. "Highly Fluorescent Semiconducting Polymer Dots：(1)Applicate in Imaging of Latent Fingerprints；(2) Survive in Surroundings of High Ionic Strength by Packing Layered Double Hydroxides." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/4y2km2.
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碩士國立中山大學
化學系研究所
105
1.Dual Colorimetric and Fluorescent Imaging of Latent Fingerprints on Both Porous and Nonporous Surfaces with Near-Infrared Fluorescent Semiconducting Polymer Dots Semiconducting polymer dots (Pdots) have recently been proven as a novel type of ultrabright fluorescent probes that can be extensively used in analytical detection. Here we developed a dual visual sensor based on Pdots for fingerprint imgaing. We first designed and synthesized two types of near-infrared fluorescent polymers and then embedded ninhydrin into the Pdots matrix. The resulting Pdots assays showed the colorimetric and fluorescent dual-readout abilities to detect latent fingerprints on both porous and nonporous surfaces. The developed fingerprints clearly revealed first-, second-, and third-level details with high contrast, high selectivity, and high efficiency. We also grafted the chemical groups on the nanoparticle surface to investigate the mechanisms involved in the fingerprint development processes. We further utilized this assay in note paper and check for latent fingerprint imaging. We believe that this dual-readout method based on Pdots will create a new avenue for research in fingerprint detection and anti-counterfeiting technology. 2.Highly Fluorescent Semiconducting Polymer Dots Survive in Surroundings of High Ionic Strength by Packing Layered Double Hydroxides Semiconducting polymer dots (Pdots) recently have been known as a potential material in ion sensing, biosensing and bioimaging because of their extraordinary fluorescence brightness, good stability, facile surface functionalization, and low cytotoxicity. By using the exchangeable and protective properties of long-known Layered Double Hydroxides (LDH), here we report a new hybrid of LDH and Pdots which can successfully prevent Pdots from self-aggregation, and make it possible for Pdots to survive in surroundings of high ionic strength for a long time, and still to have bright fluorescence.
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Jenquine, Kelsie Lynn. "The effect of latent fingerprint processing on the recovery of gunshot primer residue particles from latex gloves." Thesis, 2019. https://hdl.handle.net/2144/36524.
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Gunshot primer residue (P-GSR) is released from the openings of a firearm when it is discharged12,13. P-GSR is made of microscopic particles that are considered characteristic of being derived from firearm ammunition when composed of barium (Ba), lead (Pb), and antimony (Sb) and have the correct morphology4. Morphology describes the shape of the P-GSR particle, which can be spherical, irregularly shaped, and must be non-crystalline. Forensic labs are commonly requested to test for the presence of P-GSR on evidential items, such as hands, clothing, vehicles, and gloves, in order to provide circumstantial evidence showing that they were, in some way, possibly involved with a shooting. Occasionally these evidential items are also expected to undergo fingerprint processing to potentially link someone to a crime. Latex gloves are often utilized in the commission of a crime with the impression that fingerprints cannot be left behind, however latent prints can often be developed on this non-porous material. Due to the evidential value of fingerprints and in order to ensure that potential prints are not damaged during P-GSR collection, latent print development is routinely performed first. Considering that P-GSR particles are easily dislodged, it is possible that some loss of P-GSR may occur during latent print processing.
The purpose of this study was to evaluate the effect of processing a non-porous item for latent fingerprints on the subsequent recovery and detection of P-GSR. Latex gloves were worn during the discharge of either a pistol or a revolver and then processed for latent prints by undergoing cyanoacrylate fuming followed by either white powder or yellow dye. The latex gloves were then sampled for P-GSR using aluminum stubs containing an adhesive coating which were dabbed over the gloves until they loss their tackiness. The stubs were then carbon coated using a Denton Vacuum Desk IV in order to prevent charging in the analytical instrument. Utilizing a JEOL JSM-6460LV Scanning Electron Microscope (JEOL USA Inc., Peabody, MA coupled with an EDAX Apollo X Analyzer (EDAX Inc., Mahwah, NJ) and EDAX Genesis GSR Software, the stubs were processed for three-component particles characteristic of P-GSR.
It was determined that P-GSR can still be recovered on latex gloves after undergoing latent print processing involving cyanoacrylate fuming followed by either white powder or yellow dye processing. Three-component particles were found on both the interior and exterior of the latex gloves after being processed for latent prints. On average, 33 P-GSR particles were found on the exterior of the gloves and four P-GSR particles were found on the interior of the gloves. Although significantly less were found on the interior of the gloves (<10), it is recommended that both sides of gloves be stubbed when collecting P-GSR for the greatest chances of collecting three-component particles if they are in fact present on a pair of gloves.
Although more particles were found on the gloves that were not processed for latent prints, a sufficient number of particles (≥3 particles) were consistently found on the latex gloves after undergoing latent print processing to provide a positive P-GSR result according to the Massachusetts State Police Crime Lab guidelines for P-GSR analysis. Therefore, this research shows that latex gloves can first be processed for latent prints and then subsequently be processed for P-GSR effectively in order to try and obtain both forms of evidence for a case.
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TSENG, PO-CHANG, and 曾柏彰. "Luminescence Characteristics of NaAl11O17:Mn2+ and Sr2MgSi2O7:Eu2+ Phosphors and Their Application in Latent Fingerprint Detection." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/83mfpw.
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碩士國立高雄科技大學
電子工程系
107
The identification of latent fingerprints has been widely used in the field of forensics, this is because that fingerprints of each person and each finger are unique and do not change with age. However, fingerprints are not easy to be detected if they are not stained with colored substances such as blood or pigments. In order to identify these potential fingerprints, the most extensive and simple method is the powder dusting method. Consider the characteristics of phosphor sources. Powders been used traditionally have the disadvantages of low contrast, low sensitivity, and easy interference by the background, as a result, the detected latent fingerprints is ambiguous. Accordingly, to achieve good identification of latent fingerprints phosphors should have the characteristics of high luminance intensity along with small particle size. Four subjects were studied in this theme: (1) NaAl11O17:Mn2+ phosphor powder was synthesized by solid-state reaction method, and the effect of activator concentration, sintering temperature on the luminescent properties of phosphor was investigated. (2) Sr2MgSi2O7:Eu2+ phosphor was synthesized by co-precipitation method. The effects of activator concentration, sintering temperature, and sintering time on the luminescent properties of phosphor were investigated. (3) Analysis of luminescence properties of NaAl11O17:Mn2+ and Sr2MgSi2O7:Eu2+ phosphors at different ambient temperatures. (4) Application of NaAl11O17: Mn2+ and Sr2MgSi2O7:Eu2+ phosphors for fingerprint identification. Furthermore, luminescence properties of NaAl11O17:Mn2+ and Sr2MgSi2O7:Eu2+ phosphor were measured and compared. The potential application of phosphors in latent fingerprint detection was investigated as well. As compared with the NaAl11O17:Mn2+ phosphor, the Sr2MgSi2O7:Eu2+ showed a higher luminescence intensity and is more suitable for latent fingerprint identification. Additionally, both kinds of synthesized phosphors exhibited good thermal stability. This indicates that the as-prepared phosphors are suitable for light-emitting diode illumination, as They do not cause a sharp decrease in luminescence intensity when the temperature is increased.
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HUNG, YING-CHE, and 洪英哲. "Synthesis and Luminescence Characteristics of Deep-Red Emitting Phosphor and Its Application in Latent Fingerprint Detection." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/34858t.
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碩士國立高雄應用科技大學
電子工程系
106
The white light emitting diode (LED) has the characteristics of small size, high luminescence efficiency and long life, which is considered to be a lighting source to replace incandescent and fluorescent lamps. Traditionally, the commercial white LED is fabricated using a blue chip to pump the yellow Y3Al5O12:Ce3+ phosphor, however, which suffers from low color rendering index and high correlated color temperature, attributing to insufficient red component in luminescent spectrum. Accordingly, to achieve a high quality white LED, the synthesis of red phosphors is a crucial topic. Four subjects were studied in this theme: (1) Synthesis of Mg2TiO4:Mn4+ deep-red phosphor by solid state reaction; the effects of activator concentration, sintering temperature, sintering time, and the addition of flux and sensitizer on the properties of phosphor were investigated. (2) Synthesis of Mg2TiO4:Mn4+ deep-red phosphor by sol-gel method, herein, the concentration of citric acid was the key parameter. (3) Investigation on the luminescence properties of Mg2TiO4:Mn4+ deep-red phosphor under different ambient temperatures. (4) Application of Mg2TiO4:Mn4+ deep-red phosphor on fingerprint identification. In this study, Mg2TiO4:Mn4+ deep-red phosphors were synthesized by solid-state reaction and sol-gel method. The phosphor showed a red emission peak at wavelength of 661 nm (2E2 → 4A2) when excitation was at wavelength of 343 nm. The properties of phosphor synthesized with the Sol-gel method were better than that prepared with the solid-state reaction, because the crystallinity and luminescence intensity of the phosphor were significantly improved. In addition, measurements showed that the luminescence intensity of phosphor had a linear relationship with the ambient temperatures, and the phosphor has a potential for fingerprint identification application.
34
Sun, Main-Ping, and 孫曼蘋. "Evaluation of Sythesized 1,2-indanedione Compared with DFO and Ninhydrin as Reagent for Development of Latent Fingerprint on Paper Surface." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/13943128375862834792.
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碩士中央警察大學
刑事警察研究所
89
1,2-indanedione, a recently synthesized compound was found to be potential of reacting with the amino acid components contained in the latent fingerprint as a rigorous source of development agent. This research topic first aims at attempting to accomplish the synthesis of 1,2-indanedione in the working lab. The product obtained was then used as a developing agent for latent fingerprint on porous surface of various paper stuffs. By applying appropriate attributes to enhance the print outcome, an empirical evaluation was resumed by comparing the visibility effects with that of DFO as well as that of Ninhydrin reagents on identical experimental conditions. It was strongly manifested from the results of this research that the latent print if treated with 1,2-indanedione and then followed by enhancement with zinc tonic solution (under the excitement with 535nm blue-green light and viewing with 590nm dark-red filter), the ridge pattern of it shows much stronger fluorescence than that if with DFO and that with Ninhydrin application. In addition, when latent prints were developed by different sequential treatments, 1,2-indanedione has been proved to be the best priority. Moreover, the manipulation of dry-method application of 1,2-indanedione with steam-iron setting at cotton temperature can acquire better resolution of fingerprint.
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Lauzon, Nidia. "Imagerie moléculaire d’empreintes digitales par spectrométrie de masse : potentiels et applications en science forensique." Thèse, 2018. http://hdl.handle.net/1866/21579.
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