We present a three-dimensional, forward model of blood droplets in ight. The proposed model is based on a set of ordinary di erential equations (ODEs) incorporating viscous drag and gravitational forces. We validate the model against laboratory experiments in which a mock crime scene is constructed. The experiments consist of a ballistics gel containing transfer blood or porcine blood shot by a riot ball from a paintball gun constituting a simulated bloodletting event. The experiments are captured using highspeed stereo camera pair from which three-dimensional trajectories can be extracted using tracking software. The long-term goal is to develop an accurate framework for forensic Bloodstain Pattern Analysis (BPA). / UOIT

We present a three-dimensional, forward model of blood droplets in ight. The proposed model is based on a set of ordinary di erential equations (ODEs) incorporating viscous drag and gravitational forces. We validate the model against laboratory experiments in which a mock crime scene is constructed. The experiments consist of a ballistics gel containing transfer blood or porcine blood shot by a riot ball from a paintball gun constituting a simulated bloodletting event. The experiments are captured using highspeed stereo camera pair from which three-dimensional trajectories can be extracted using tracking software. The long-term goal is to develop an accurate framework for forensic Bloodstain Pattern Analysis (BPA). / UOIT

Blood is one of the most common and important types of physical evidence present at a crime scene. When liquid blood is acted upon by external physical forces, that blood is often distributed through the air in the form of droplets, with bloodstains and bloodstain patterns deposited on adjacent surfaces. Using the mathematical relationship that exists between the blood droplet and resultant bloodstain’s length and width ratio, the angle at which the blood droplet impacted the receiving surface can be determined. Using this relationship, it becomes possible for Bloodstain Pattern Analysts to determine the three dimensional Region of Origin for the blood source from which the bloodstains under examination have originated. A Bloodstain Pattern Analyst performs angle of impact calculations from bloodstains for the purpose of making a three dimensional determination of blood source Region of Origin. The reliability of that determination is based on an assumption that one of the most important biological properties of blood; the amount of red blood cells or hematocrit value, has no influence over the length to width ratio of a bloodstain. As a consequence the Impact angle = arcsine [width/length] calculation has been assumed accurate regardless of the 'unknown' hematrocrit value. This thesis investigated the effect of the hematocrit value on the angle of impact calculation and thus the ability to determine the three dimensional blood source Region of Origin. Bloodstains were created by releasing a series of 18µL droplets, with ten different hematocrit values, onto a ceramic tile at four different angles. The resultant bloodstain length and width was measured and impact angle calculated. Evaluation of the research data shows that the hematocrit value significantly affects the bloodstains length and width. However, it is apparent that there is close agreement between the known and calculated impact angles irrespective of the hematocrit value.

Bloodstain Pattern Analysis is a rapidly growing area of research in the forensic science field. It is not uncommon for blood to be present on surfaces such as clothing, furniture, carpet, and more, during the commission of a crime. . Research of how blood interacts with different porous surfaces, such as textiles and fabrics, is relatively unexplored in the field of forensic science. Prior to a bloodshed event in which blood may be deposited onto clothing, the fabric may have been laundered in a variety of ways. In this research, swatches of a 100% nylon, water resistant fabric were subjected to seventeen different laundering and soiling processes. The laundering products used included Tide® Liquid Laundry Detergent, Downy® Fabric Softener, Downy® Unstoppables In-Wash Scent Boosters, Bounce® Dryer Sheets, Clorox® Zero Splash Bleach Packs, and OxiClean™ Max Force Laundry Stain Remover. Soiling included wearing swatches of fabric and leaving them in direct sunlight. Whole human blood was inverted, vortexed, then transferred using a disposable transfer pipette. The sample was held 36 in./3 ft. above each sample at a 90-degree angle, using an apparatus made from a flat edge and a protractor to ensure consistency. Blood drops were deposited onto each swatch of fabric, photographed, and microscopically examined. The drip stains were measured and characteristics of the blood, fabric, and the interaction of the two were recorded. Results showed some trends, such as an increased breakdown of fabric structure when bleach was used, and an increase in wicking when treated with scent boosters. Overall, the results were varied in all comparisons.

Violent crimes involving bloodshed may result in the formation of a number of blood drops that move through air and impact onto a surface producing a bloodstain pattern. Bloodstain Pattern Analysis (BPA), the analysis of the position, distribution, size and morphology of the stains within the pattern present at a crime scene, may provide information about the events that gave rise to the bloodshed. The location of blood origin, i.e. victim’s position at the moment of wounding and (or) wound location, determination is of major interest to BPA. This study investigated the dynamics of formation and flight of blood drops commonly found at a crime scene (so-called passive, cast-off, impact and gunshot drops) with the aim to facilitate blood origin determination. Features of blood drop formation at passive dripping with correlation to dripping surface characteristics were studied experimentally. A numerical scheme for accurate blood drop flight characteristics modelling, including oscillations, deformation and disintegration, was developed and validated against a number of analytical and experimental cases with special attention to the passive blood drop oscillations and ultimate deformation at terminal velocity, cast-off and impact blood drop deformation and breakup features. This provided an efficient and accurate method for typical blood drop flight reconstruction from the blood origin to impact as well as from the bloodstain location to the possible blood origin. Factors affecting blood drop trajectory and blood origin estimation were studied using the developed scheme.

The current methods used by forensic experts to analyse blood spatter neglects the influence of gravitation and drag on the trajectory of the droplet. This research attempts to suggest a more accurate method to determine the trajectory of a blood droplet using multi-target tracking. The multi-target tracking problem can be rewritten as a linear programming problem and solved by means of optimization and numerical methods. A literature survey is presented on relevant articles on blood spatter analysis and multi-target tracking. In contrast to a more advanced approach that assumes a background in probability, mathematical modelling and forensic science, this dissertation aims to give a comprehensive mathematical exposition of particle tracking. The tracking of multi-targets, through multi-target tracking, is investigated. The dynamic programming methods to solve the multi-target tracking are coded in the MATLAB programming language. Results are obtained for different scenarios and option inputs. Research strategies include studying documents, articles, journal entries and books. / MSc (Applied Mathematics), North-West University, Potchefstroom Campus, 2014

The current methods used by forensic experts to analyse blood spatter neglects the influence of gravitation and drag on the trajectory of the droplet. This research attempts to suggest a more accurate method to determine the trajectory of a blood droplet using multi-target tracking. The multi-target tracking problem can be rewritten as a linear programming problem and solved by means of optimization and numerical methods. A literature survey is presented on relevant articles on blood spatter analysis and multi-target tracking. In contrast to a more advanced approach that assumes a background in probability, mathematical modelling and forensic science, this dissertation aims to give a comprehensive mathematical exposition of particle tracking. The tracking of multi-targets, through multi-target tracking, is investigated. The dynamic programming methods to solve the multi-target tracking are coded in the MATLAB programming language. Results are obtained for different scenarios and option inputs. Research strategies include studying documents, articles, journal entries and books. / MSc (Applied Mathematics), North-West University, Potchefstroom Campus, 2014

This thesis is divided into two parts, each of which examines aspects of bloodstain analysis where gravity is the main force applied to blood. Part I is a preliminary study on the dynamics of blood flow on various inclined surfaces and examines the use of blood analogs for easy test replication. The flow of uncoagulated human blood at different volumes and temperatures was examined on wood at a set angle of 1.5°, and on glass at varying incline angles. Glycerol solutions of 59% and 42% were used to represent blood at 23°C and 37°C respectively. Glycerol flow trials of similar volumes were conducted on wood, PVC and glass. Fluid flow plots of distance versus time exhibited double exponential curve behaviour, although a power-law relationship derived by H. E. Huppert's (1982) flow expression was obtained for blood flowing on inclined wood. Blood flow exhibited several observable characteristics; a decreasing width of the leading edge over time, and streaking and component separation of the leading region at very low speeds. On a glass surface, the width of the initial flow region decreased and initial speed increased with increasing angles. The glycerol analogs used in this study did not represent their blood counterparts well due to differences in physical properties of the fluids. Part II of this study focuses on the forensic value of passive bloodstains on three fabrics; 100% cotton drill, 65/35 polyester cotton, and 100% Shantung silk. 26 µL drops of 37°C human blood were deposited onto the three fabrics and paper from a height of 14 cm at various impact angles. The stains were photographed and analysed qualitatively and quantitatively using computational methods. 100% cotton drill, 65/35 polyester cotton and ironed 100% Shantung silk provided useful forensic values such as direction of travel and angle of impact. Overall, this study has provided useful preliminary data for further research work.

Os corantes benzazólicos fluorescentes por ESIPT são conhecidos pela sua grande estabilidade e variabilidade no comprimento de onda da sua emissão de fluorescência. Novos derivados, nomeados HBs, foram estudados como corantes para sangue por possuírem grupos sulfônicos na sua estrutura molecular, o que é característico dos corantes proteicos utilizados para a análise de sangue. Estudos sobre essa aplicação foram desenvolvidos nesse trabalho, visando estabelecer vantagens e desvantagens em comparação aos reagentes mais utilizados. Os resultados foram satisfatórios para essa utilização, sendo tão sensível quanto o Amido Black e permitindo a combinação de técnicas com diferentes reveladores, sendo eles: Amido Black, Cianoacrilato e Luminol. Este trabalho também estudou a síntese do Luminol reproduzindo metodologias descritas na literatura, além da síntese do isômero Isoluminol. A obtenção de um produto com alto grau de pureza é difícil. Como são necessárias várias etapas, o rendimento do produto não é alto. / The benzazole fluorescent dyes by ESIPT are known for their high stability and fluorescence emission wavelength variability. New derivatives, appointed HBs, were studied as blood enhancement dyes once they have sulfonic groups in its molecular structure, which is characteristic of protein dyes used for blood analysis. Studies about this application were developed in this work, in order to establish its advantages and disadvantages compared to commonly used reagents. The results were satisfactory for the referred use, being as sensitive as Amido Black and allowing for techniques combination with different developers: Amido Black, Cyanoacrylate and Luminol. This work also studied the Luminol synthesis by reproducing methodologies described in the literature, as well as the isomer Isoluminol synthesis. The obtaining of a product with high purity is difficult. As several steps are required, the product yield is not high.

Os corantes benzazólicos fluorescentes por ESIPT são conhecidos pela sua grande estabilidade e variabilidade no comprimento de onda da sua emissão de fluorescência. Novos derivados, nomeados HBs, foram estudados como corantes para sangue por possuírem grupos sulfônicos na sua estrutura molecular, o que é característico dos corantes proteicos utilizados para a análise de sangue. Estudos sobre essa aplicação foram desenvolvidos nesse trabalho, visando estabelecer vantagens e desvantagens em comparação aos reagentes mais utilizados. Os resultados foram satisfatórios para essa utilização, sendo tão sensível quanto o Amido Black e permitindo a combinação de técnicas com diferentes reveladores, sendo eles: Amido Black, Cianoacrilato e Luminol. Este trabalho também estudou a síntese do Luminol reproduzindo metodologias descritas na literatura, além da síntese do isômero Isoluminol. A obtenção de um produto com alto grau de pureza é difícil. Como são necessárias várias etapas, o rendimento do produto não é alto. / The benzazole fluorescent dyes by ESIPT are known for their high stability and fluorescence emission wavelength variability. New derivatives, appointed HBs, were studied as blood enhancement dyes once they have sulfonic groups in its molecular structure, which is characteristic of protein dyes used for blood analysis. Studies about this application were developed in this work, in order to establish its advantages and disadvantages compared to commonly used reagents. The results were satisfactory for the referred use, being as sensitive as Amido Black and allowing for techniques combination with different developers: Amido Black, Cyanoacrylate and Luminol. This work also studied the Luminol synthesis by reproducing methodologies described in the literature, as well as the isomer Isoluminol synthesis. The obtaining of a product with high purity is difficult. As several steps are required, the product yield is not high.