NALSAR University of Law & Truth Labs Advanced PG Diploma in Criminal Law and Forensic Science Term-II Forensic Science 2020-2021 FS2-1.2.5 – FORENSIC CHEMICAL & GENERAL SCIENCE ID CLFS107_20 NAME KARTHIK P SUBJECT Paper II - 1.2.5. Forensic Chemical and General Science QUESTIONS 2, 9, 8, 4, 3 ATTEMPTED PAGES 23 2. Role of Forensic Psychology in Crime Investigation In 1981 Professor Lionel Haward, one of the founding fathers of Criminal Psychology, described the four roles that psychologists may perform when they become professionally involved in criminal proceedings. These are given below. Criminal Investigations The role of a Forensic Psychologist in Criminal Investigations can take a variety of forms. From the list of functions within the quote above, it may be seen that the role of the psychologist in assisting the police can be wideranging. Crime Analysis Crime Analysis (sometimes also called intelligence analysis) is one field of work which draws upon Forensic Psychological methods. Crime analysts are generally employed by the police in order to analyse crime data to aid the police carryout their roles. One of the most common roles of crime analysts is that of case linkage. This process involves the linkage of crime based on the similarities in the behaviours of the offenders as reported by the victim or as inferred from the crime scene. For example, let us examine a rape case committed by a stranger on a woman walking home alone after a night out with her friends. Crime analysts could use the details of this case – the fact that she had just left a night club, that the rapist took some of her clothing away from the scene with him, the contents of the threats used towards the woman – in order to check against an already established database of similar crimes to see whether there are any similarities to past crimes. If matches are found – the same threats were used, similar items of clothing taken by a rapist, and it was in a close geographical location to another rape – then this information can be used by the police to investigate the potential that the same individual offender has committed both crimes. This allows the focusing of the resources of the investigation in order to avoid duplication of work. Offenders Profiling or Criminal Investigative Analysis Offender Profiling has received a great deal of attention from the media in recent years. Media reporting of the utilisation of Forensic Psychologists in high profile cases has introduced the general public to the notion of offender profiling. While this has raised the profile of the field, it could be argued that the (largely) sensationalist portrayal of profiling resulted in a general confusion of what profiling actually is, how often it is done and who does it. This uncertainty amongst the general public is not altogether surprising however, as there is an absence of an agreed definition of the term ‘profiling’, even in academic circles. What we can be clear about is that profiling uses information gleaned from the crime scene relating to the offender’s behaviour during the crime. This can be pooled with other information, such as victim statements (if available), in order to draw conclusions about the nature of the person who committed the crime. Interviewing, Detecting Deception and Eye Witness Research One of the most important tasks during investigation is collecting reliable evidence in order to put together a case of what happened during the event in question. One of the main sources of this evidence is the people who were eyewitnesses to the event. In order to gain this information, an interview needs to be conducted by the investigating police officers with the aim of gaining as much accurate information from the witness as possible. In addition, once the suspect has been identified, he or she too is interviewed in order to gain his or her view of events and to possibly extract a confession to the crime. Hence the interview (whether with a witness or suspect) and the manner in which it is conducted can be crucial to a case. Psychologists have been instrumental in developing guidance and advice on how best to interview witnesses and suspects and have also provided training to various police forces on these techniques. The police can also use psychologists in order to gain advice on how to interview particular types of witnesses or suspects. For example, psychologists have conducted research into interviews with vulnerable witnesses such as the young, the elderly and learning disabled witnesses. This research can be used to inform the police on how best to retrieve the information that they require from such witnesses without causing them too much stress while at the same time ensuring that the information received is as accurate as possible. Research performed by Forensic psychologists investigating the detection of deception also has useful applications for the police when interviewing witnesses and in particular suspects. Police Psychology The information here, thus far, been concerned with the application of psychological knowledge to assist in police investigation. However, there is another field within which the work of Forensic Psychologists, and the application of their knowledge, is useful to the police. Like many organisations, the police force itself presents its own challenges – what type of person makes a good police officer? What is the best way to train police officers? How might the attendance at unpleasant scenes of crime, or repeated exposure to negative events, impact on an individual and how are those affected in this way best treated? This area of work is not a new one – psychologists, both Occupational and Forensic, have been advising the police on such matters for the last twenty-five years or so. Psychologists have contributed their knowledge to the process of police officer recruitment through the introduction of psychometric tests which measure psychological characteristics that may be important in relation to such work. These could assess, for example, whether a person is an assertive individual, open to persuasion, and conscious of detail. Psychologists have also provided advice on the composition of interviews and assessment centres which will eliminate those who do not have the necessary qualities for the role as well as providing an indication of those who will prosper in such a role. Another important area of police interest where psychologists have an ongoing input is the moderation of police stress. The stress faced by police officers is somewhat different from that in other types of employment. Whereas stress can be elevated in most jobs through organisational change, such as decreased workload or a pay rise, the police can be faced with unexpected, perhaps threatening, situations at any time during their daily work. These events, due to their unpredictable nature, cannot necessarily be mediated by organisational change. So the police also need stress management measures that can assist at an individual level, as and when they are needed. Psychologists have been instrumental in advising the police on what mechanisms would be beneficial (such as peer counselling and self-help programmes), but will also provide professional services to police officers who require more intensive stress management. Expert Witness Court cases can involve complex issues including the presentation of information that is judged to be beyond the knowledge of the average layperson who may sit on a jury. In such situations, the court permits the calling of an expert witness who, by definition, has an expertise relating to the issue in question. Under the circumstances expert witnesses are permitted to provide their opinion (rather than the facts) on the issue being discussed. The way the expert witnesses are called to the court, however, varies from one jurisdiction to another. For example, in some countries within Europe, an expert witness is called by the court itself in order to provide information as and when it is needed. The use of the psychologist as an expert witness has, in the past, been constricted by the notion of the expert having to provide information that is beyond the knowledge of the average person. Historically then, the admissibility of a psychologist’s opinion was often limited to provide evidence relating to mental impairment or the psychological functioning of an individual. However, in recent years, the psychologists’ expertise has been increasingly recognised and they are now being called upon as evidence in relation to a wide variety of issues. Some examples of these are the impact that the interviewing techniques have on a suspect or witness, the reliability of eyewitness testimony, the clinical assessment of suspect or witness, or the use of profiling techniques during an investigation. Forensic Psychologists and Assessment and Treatment of Offenders Forensic Psychologists, are heavily involved in work concerning the assessment, rehabilitation and management of offenders, either in the community or when held in incarceration. This role can involve working with the offenders to reduce their likelihood for reoffending in the future or a more clinical role addressing the psychological needs of offenders. These psychological needs may (or may not) result from the effects of crime they committed (for example the development of post traumatic stress disorder or realisation of the impact of their offence on their victim) or the environment within which they are held (for example developing depression due to being away from the family or anxiety brought on by respective bullying from other prisoners). This work can be both varied and challenging in nature. One of the first and ongoing concerns of a Forensic Psychologist working with offenders post-sentence is the assessment of the offenders. This encompasses an in-depth analysis of their risk of reoffending, their risk of harm (to others as well as themselves) and their needs (such as accommodation, finances and mental health, for example). These assessments can be used in the management of the offenders’ highlighted risks and needs, informing the planning of the activities that the offenders will undertake during their sentence. This could include the provision of basic skills courses, treatment programmes, one to one work on the particular issues, and so on. In addition, if an offender is on a community sentence and has been assessed to be high risk to the public, then it may be the case that the offender becomes subject to the monitoring arrangements in order to reduce the risk that he or she poses. The forensic psychologist can provide an input to each of these arrangements on an operational level but can also provide managerial and advisory support to those delivering such interventions. In the recent years there has been a growth in the use of treatment programmes with the offenders. Forensic Psychologists have been active in this development contributing to the design, delivery and management of programmes which attempt to address the offenders’ thoughts, attitudes and behaviours that contribute to their offending behaviour, and prevent further offending. Psychologists are also involved in the management of these programmes, ensuring that the right offenders are placed on such programmes and that the programmes are delivered in the manner in which the designer intended. Research has shown that badly delivered programmes can be ineffective but at worst be damaging. However, the role of the prison or probation psychologist is not limited to rehabilitation related work. Forensic psychologists within these settings can also be involved in undertaking research, overseeing training of prison or probation staff, preparing reports for the courts detailing the risk level, needs and other information relating to the individual offender, attending court, attending team and area meetings and the inevitable administration! 9. Classification of Poisons and their effect on human bodies ? Ans : CATEGORIES The samples received for the examination in Toxicology Division can be broadly categorized in to: A. B. C. D. E. F. Gaseous and Volatile poisons Inorganic poisons (Metallic and Anions) Neutral poisons (Organic non Volatile) Basic poisons/drugs (Organic non volatile) Acidic poisons/drugs (Organic non volatile) Miscellaneous poisons A.1 GASEOUS POISONS Gaseous poisons exist in an industrial environment, only a few are seen frequently in forensic practice. Carbonmonoxide is available in illuminating gas, automobile exhaust fumes, and fire combustion smoke, furnace gas, heavy auto traffic garages and refineries. Available forms: Available in solid, semi solids, liquids and gaseous forms. Available forms of cyanide: Cyanide is generally available in the following chemical forms such as Potassium cyanide (KCN), Sodium cyanide (NaCN), Potassium thocyanate (NH4SCN), Silver cyanide ferrocyanide (K4Fe (Cn) 6), Ammonium (AgCN), Mercuric cyanide (Mg(CN)2) Hydrocyanic acid (HCN), etc. In the form of certain glycosides, hydrocyanic acid occurs in large number of plants. Volatile poisons are in various forms as cyanide, alcohols, phosphorus, phenols etc Source and form of crime questioned sample: Samples collected during postmortem examination and at scene of crime are received from Investigating Officers and Judiciary is in the form of viscera, body fluids, material objects and plant materials. In survival cases like living persons stomach wash, vomited material and cloths etc., blood sample, urine and faeces if available. Suspected material stained recovered from the possession of the victim or accused and from the scene of crime such as medicines, containers, foods and drinks, residual poisonous materials etc. Control sample: Pure forms volatile and gaseous poisons standardized for Laboratory purpose procured from recognized Laboratories are used for comparative chemical analysis. A.2 Volatile poisons Example : Cyanide Cyanide is extremely rapid acting and capable of causing death within minutes. The classical odour of bitter almonds is not detected by everyone and seems to be genitically determined. Hydrocyanic acid and the cyanides are true protoplasmic poisons, since they arrest the activity of all forms of living matter by unhibitting tissue oxidation and suspending vital function. Onset of symptoms of cyanide poisoning depends on the type of exposure. Hydrogen cyanide vapours are the most rapidly acting, with symptoms occuring within seconds and death within minutes. When cyanide salts are ingested, onset of toxicity is delayed somewhat due to slow absorption. The severity of acute poisoning is determined by the dose and exposure time. B. INORGANIC POISONS (METALLIC AND ANIONS) The poisons in this group have been used frequently, probably because in general they are potent, tastless, readily available, and produce symptoms similar to many common diseases. For example, the substitution of arsenious oxide for the contents of one or two prescribed capsules can have fatal results with all the appearance of straightforward drug overdose suicide. Definition: An acid or a base. inorganic poison may be metal, a metalloid, metal element, a salt, an Available forms: Available forms may be a liquid or in a solid form. The Important metallic poisons in this group are: Arsenic, antimony, mercury, lead, copper, thallium, zinc, manganese, barium and radioactive substances. The salt of the metals are toxic and hence are of great toxicological importance. A number of unrelated poison are in gaseous form. Through there are very many of these in existence especially in the industrial environment, only a few are seen frequently in forensic practice. C. NEUTRAL POISONS (ORGANIC NON-VOLATILE) Organophosphorous-Insecticides: Lange and _kreger in 1932 observed the strong cholonegic effects of vapours of diethylphosphorous fluoridate in human being. However the practical development of these compounds as insecticides is mainly due to the original and extensive work of Schrader' and his co-workers from 1937. The organophosphorus compound has a great variety of pesticidal properties like insecticides, acaricides, nematocides, herbicides, defoliants and fumigants. Most of the compounds of this group are required only in small quantities for the control of pests. Pesticidal activity is also very rapid. Many of the compounds break down to nontoxic compounds very rapidly in vertebrate animals. Also they do not accumulate in the body animal. Though many of the early compounds of this group had relatively high toxicity to vertebrates. recently a large number of organophosphrous compounds with moderate to low toxicity to mammals have been synthesized and have been put in the market. More than 100,000 different organophosphorus compounds have been synthesized and evaluated as pesticides of these more than 80 are widely used in agriculture. Definition: These are considered as derivatives of the corresponding acids or hydrogen phosphide (phosphine). Available forms: Available in solid, semi solid and liquid forms. Organophosphrous Insecticides, Derivatives Of 1. Phosphoric acid (ddvp-phosphamidon etc.) 2. Thiophosphoric acid (parathion, memeton etc.) 3. Dithiophosphoric acid (malathion etc.) 4. Pyrophosphoric acid (tepp, schraden etc.) 5. Phosphonic acid (epn) Derivatives of phosphorus acid have the ending _ITE' and those of phosphoric acid the ending _ATE'. For example the diethyl ester of phosphorus acid carries the name diethylphosphite and that of phosphoric acid is called diethyl phosphate. D. BASIC DRUGS / POISONS (ORGANIC NON- VOLATILES) Basing on their physiological action, basic drugs are broadly classified into the following groups: 1. Narcotic: These drugs affect brain in over and above therapeutic dose. e.g.Orium. Morphine. Heroine, Codiene 2. Deliriant poisons: They also affect the vital part of Brain ; e.g. Atropine, Hyoscyamine, Cocaine, Muscurine (Fungi mushrooms) 3. Spinal affecting drugs: These effect heart. e.g. Strychnine, Brucine. 4. Cardiac arrest drugs: These affect heat. e.g. Quinine, Acotinine, Nicotine. Drug abuses are common. Drugs are consumed by the victim in more than therapeutic doses and hence they go into the blood and urine. So in any clinical cases, extraction of drugs. in urine, blood and stomach contents are essential in order to identify the exact nature of drug consumed by the victim. Extra care should, therefore, be taken to take the sample of blood, urine and stomach contents. Definition: Drugs, which are alkaline in nature, are called basic drugs. These readily react with acids. Available forms: Drugs/poisons are available as powders, plant products etc. Source and form of crime/questioned sample: Samples collected during postmortem examination and at scene of crime are received from Investigating Officers and Judiciary are in the form of viscera, body fluids, material objects and plant materials. In survival cases like living persons stomach wash, vomited material and stained cloths etc., blood sample, urine and faces if available. Suspected material recovered from the possession of the victim or accused and from the scene of crime such as medicines, containers, foods and drinks, residual poisonous materials etc. E. ACIDIC DRUGS/POISONS (ORGANIC NON VOLATILE) Poisons have been classified differently by different persons engaged in the detection of poisoning cases. Some of the important organic poisons are barbiturates, salicylates etc. Barbiturates are drugs most frequently involved in adult poisoning. The synonyms of barbiturates are: Sleeping pills, guufballs, yellow jackets (Nembutal), red devils (seconel) blue deave (Amytal). These are mostly used as Anticonvulsant, Subhypnotic, sedative, dyprotic, Annaestic, antidote for convulsants (Strachhnine). The MLD value is to 3 gms for 70 Kg. Man depending upon derivative potency, short acting members (rapid onset) are more potent, longacting members are less potent. The symptoms of drug poisoning may be Lethargy, ataxia, sleep to deep coma, lower body temperature, marked fall in blood pressure, respiratory depression, anaxia, cynosis, flaccid limbs, retention of urine is common, usually contrition of pupil but dilation in pupil later mayoccur, deep coma, death due to respiratory arrest, frequently associated with marked cardio vascular collapse or prenumonia. Definition: Drugs which are acidic in nature are called acidic drugs. They readily reacts with base. The main acidic drugs are Barbiturates and Salycillates. Available forms: Drugs/poisons are available as powders, plant products etc. F. MISCELLANEOUS POISONS Mechanical Poisons: Mechanical poisonous substances are included in section 328 IPC within the meaning of poison, and include powdered glass, pins, needles; inhalation of glass fibers, chopped animal hairs etc. out of these, and powdered glass has some medico-legal importance. Rarely, needles or pins are swallowed for suicidal purposes. Glass powder is some times used for homicidal purposes and destroying cattle but rarely selected for suicidal purposes. Glass does not produce the desired effect, if it gets entangled in the mucous or food in the stomach. Similarly, it will not have any bad effects, if it is well powdered. Plant Poisons: There are some poisonous plants, which are often used by the criminals as a weapon in different types of crimes. These can be used in homicidal * suicidal acts, abortificients, travelers cheating, as cattle poisons and fish toxicants. Definition: Mechanical poisons are actually not poisons because they are absorbed but produce symptoms of irritant poisoning solely in consequence of Not mechanical action to their sharp angular edges and points, and their noncrystalline substance. Glass is a is mostly sodium- calcium-silicate. Heat resistant glass Chemically ordinary glass (e.g. borosil) contains about eighty percent silica and some boron oxide. Optical glass contains comparatively larger amount of lead, barium and zinc oxide. Coloured glass various metals known to give coloured compounds. Sunglass contains oxides of contains rare earths as additional elements. A poisonous plant is one which, as a whole or a part thereof, under all or certain conditions, and in a manner and in amount likely to be taken or brought into contact with an organism, will exert harmful effects or cause death either immediately or by reason of cumulative action of the toxic property, due to the presence of known or unknown chemical substances in it, and not by mechanical action. Available forms: Among mechanical poisons glass pieces, powdered glass, pins, needles etc., are of medico-legal importance. Among plant poisons opium, Dhatura, Calotropis etc., are important. Source and form of crime/questioned sample: Samples collected during postmortem examination and at scene of crime are received from Investigating Officers and Judiciary are in the form of viscera, body fluids, material objects etc. 8. Polygraph/ Lie Detection ? Ans : Polygraph testing combines interrogation with physiological measurements obtained using the polygraph, or polygraph instrument, a piece of equipment that records physiological phenomena—typically, respiration, heart rate, blood pressure, and electrodermal response (electricalnconductance at the skin surface). A polygraph examination includes a series of yes/no questions to which the examinee responds while connected to sensors that transmit data on these physiological phenomena by wire to the instrument, which uses analog or digital technology to record the data. Because the original analog instruments recorded the data with several pens writing lines on a moving sheet of paper, the record of physiological responses during the polygraph test is known as the polygraph chart. A variety of other technologies have been developed that purport to use physiological responses to make inferences about deceptiveness. These range from brain scans to analyses of voice tremors; some evidence relevant to these techniques is discussed in this report. Physiological Phenomena The physiological phenomena that the instrument measures and that the chart preserves are believed by polygraph practitioners to reveal deception. Practitioners do not claim that the instrument measures deception directly. Rather, it is said to measure physiological responses that are believed to be stronger during acts of deception than at other times. According to some polygraph theories, a deceptive response to a question causes a reaction—such as fear of detection or psychological arousal— that changes respiration rate, heart rate, blood pressure, or skin conductance relative to what they were before the question was asked and relative to what they are after comparison questions are asked. A pattern of physiological responses to questions relevant to the issue being investigated that are stronger than those responses to comparison questions indicates that the examinee may be deceptive. The central issues in dispute about the validity of polygraph testing concern these physiological responses. For example, are they strongly and uniquely associated with deception, or are there conditions other than deception that could produce the same responses? Does this association depend on particular ways of selecting or asking questions, and if so, do examiners ask the right kinds of questions and make the right comparisons between the physiological responses to different questions? Is the same association of deception with physiological response observable across all kinds of examinees in all kinds of physical and emotional states? Does it depend on factors in the relationship between examiner and examinee? Is it influenced by an examiner’s expectation about whether the examinee will be truthful? In Chapters 3, 4, and 5 we discuss in more detail the theory of the polygraph and two kinds of evidence on these questions. One comes from basic psychophysiological research on the phenomena the instrument measures. The other comes from research on polygraph testing itself. Polygraph Test Techniques Although the polygraph instrument is the centrepiece of the technique, the ability of the polygraph test to detect deception also depends critically on other elements of the process. One is the interpretation of the polygraph chart. Interpretation normally involves comparison of physiological responses to “relevant” questions (i.e., questions about the issue that is the focus of the examination) and responses to other questions that are asked for purposes of comparison.3 Interpretation is often done by the examiner, who reviews the chart and may code it according to a standard protocol. People other than the examiner may also use such a protocol to code a chart. Chart interpretation can also be done by computer. Different polygraph techniques are defined in part by the ways the relevant and comparison questions are selected and placed in a polygraph test. A considerable portion of the empirical research on polygraph testing focuses on validating particular techniques or comparing the performance of one technique with another. Three major classes of questioning techniques are in current use. The second class of techniques, called control question or comparison question testing, compares responses to relevant questions with responses to other questions that are intended to generate physiological reactions even in nondeceptive examinees. In one version of this technique, the comparison questions are selected to create a temptation to deceive: for example, “Have you ever stolen a small object from your place of work?” or “Have you ever violated a minor traffic law?” Such so-called probable lie questions are presumed to be like the relevant questions in creating a level of concern related to truthfulness. For truthful examinees, this level of concern is presumed to be higher than for the relevant questions, about which the examinee can be truthful without much anxiety. For examinees who may be deceptive about the events under investigation, it is presumed that the relevant questions create the greater level of concern and therefore a stronger physiological response. Comparison question tests are used both for specific-event investigations and for screening. The third class of techniques, commonly called guilty knowledge polygraph testing, involves questions about details of an event under investigation that are known only to investigators and those with direct knowledge of the event. We refer to these tests as concealed information tests because they are applicable even when an examinee who possesses information is not guilty and even if the information is incorrect. The questions are presented in a multiple-choice format. As these brief descriptions make clear, polygraph testing techniques vary in the ways the relevant and comparison questions differ and in how these differences, combined with an examinee’s physiological responses to them, are used to make inferences about whether the person may be lying in response to the relevant questions. In many applications, examiners take a stronger response than to comparison questions as an indication not necessarily of deception, but of the need for further interviewing or testing to determine whether deception is occurring. The lack of such a differential response or a stronger response to comparison questions generally leads to a conclusion that a respondent is being truthful. A polygraph test is part of a polygraph examination, which includes other components. A critical one, particularly in comparison question tests, is the pretest interview. This interview typically has multiple purposes. It explains the test procedure to the examinee. It explains the questions to be asked so that examiners and examinees understand the questions in the same way. Shared understanding is especially important for screening polygraphs that ask about general categories of behavior, such as “Have you ever revealed classified information to an unauthorized individual?” The pretest interview shapes the expectations and emotional state of the examinee during the test. It may be used to convince the examinee that the polygraph instrument will detect any deception. This process often involves a demonstration in which the examinee is asked to lie about an unimportant matter, and the examiner shows the instrument’s ability to detect the lie; these demonstrations sometimes involve deceiving the examinee. In comparison question testing, the interview is also used to help the examiner decide which questions to ask for comparison purposes. It is important to note that each of these aspects of the pretest interview may influence an examinee’s physiological responses to the relevant or comparison questions and, therefore, the result of the examination. Finally, the polygraph examiner is likely to form impressions of the examinee’s truthfulness, based on the examinee’s demeanor and responses in the pretest interview and during the charting. These impressions, as well as any expectations the examiner may have formed in advance of the examination, are likely to affect the conduct and interpretation of the examination and might, therefore, influence the outcome and the validity of the polygraph examination. Overall Examination A polygraph test and its result are a joint product of an interview or interrogation technique and a psychophysiological measurement or testing technique. It is misleading to characterize the examination as purely a physiological measurement technique. Polygraph examiners’ training implicitly recognizes this point in several ways. It provides instruction on the kind of atmosphere that is to be created in the pretest interview, advises on techniques for convincing examinees of the accuracy of the test, and offers guidance (in different ways for different test formats) for selecting comparison questions. Examiners are advised to control these details—sometimes following carefully specified procedures—because they can affect test results. Polygraph examination procedures often explicitly combine and interweave testing and interviewing. When a polygraph chart indicates something other than an ordinary nondeceptive response to a relevant question, the examiner typically pursues this response with questioning during the course of the examination. For example, the examiner may say, “You seem to be having a problem in the area of X [the relevant item]” and ask the examinee if he or she can think of a reason for having a strong physiological reaction to that question. The interview may reveal a misunderstanding of the question, which is then explained and reasked in a subsequent charting. Or if the reaction remains unexplained to the examiner’s satisfaction, the issue may be probed in more detail in the interview or with questions in a subsequent charting. Some examiners believe that an important use of polygraph testing is in helping narrow the range of issues that need to be investigated, using both polygraph and other investigative tools. The important role of interview conditions is also recognized in much of the practice and lore of polygraph testing. For example, it is widely and plausibly believed that polygraph results are different for “friendly” and “unfriendly” examinations (e.g., examiners proffered by the defense or by the prosecution in criminal cases). Presumably, examinees are more relaxed with “friendly” examiners and less likely to have responses that indicate deception on the test. When interviewers are hostile or aggressive, examinees may be less relaxed and may produce different physiological responses than those they would produce in response to calm, friendly questioning. Such effects of the interview situation are common in other settings, for example, the widely noted phenomenon of “white-coat hypertension,” in which blood pressure is believed to increase because of the context of a medical examination. These situational effects represent a challenge to the validity of any physiological test that does not adequately reduce the influence of variations in the interview situation on the physiological responses being measured or separate the effects of the situation from the effects of the condition (such as deception) that the test is intended to measure. In polygraph testing, the use of initial buffer items is intended to reduce situational effects on the examinee’s physiological responses. Comparison questions are also used to separate situational effects from the effects of deception by statistical means. 4. Types of Failures in Forensic Engineering and methods of Failure Analysis? Ans : FAILURE MECHANISMS (TYPES OF FAILURES) Analysis of a failure of a metal structure or part usually requires identification of the type of failures. Failures can be broadly classified in to the following: 1. Ductile and Brittle fractures 2. Fatigue Failures 3. Distortion Failures 4. Wear Failures 5. Fretting Failures 6. Liquid Erosion Failures 7. Stress Corrosion Failures 8. Liquid Metal Embrittlements 9. Hydrogen Damage Failures 10. Elevated Temperature Failures 11. Corrosion Fatigue Failures Failure can occur by one or more of several mechanisms, including surface damage such as corrosion or wear, elastic or plastics. A. DUCTILE & BRITTLE FRACTURE Ductile fractures are characterized by tearing or slippage A sliding accompanied by considerable deformation and energy absorption. The ductile fracture in mast materials have a gray, fibrous appearance. Brittle fractures are characterized by rapid crack propagation with less expenditure of energy without appreciable grass plastic deformation. Brittle tensile fractures have a bright. granular appearance, flat face type, and are produced under plastic strain conditions with title or no necking. Microscopic examination of brittle fractures will reveal inter granular or transgranular facets. Intergranular facets are grain surfaces that have been exposed by crack propagation along grain boundaries. The transgradular facets observed on brittle fractures are produced by cleavage along numerous parallel crystallographic planes, thus creating a terraced fracture surface. B. FATIGUE FRACTURE Fatigue fractures result from cyclic loading, and appear brittle on a macroscopic scale. They are characterized by incremental propagation of crack until the crass section has been reduced to where it can no longer support the applied load, and fast fracture occurs. Fatigue fractures are caused by the simultaneous action of cyclic stress tensile stresses and plastic strain. The process of fatigue may be considered as consisting of three stages: 1. Initiation of damage leading to a crack initiation. 2. Crack propagation until the remaining uncracked cross-section at a part becomes too weak by carry the loads imposed. 3. Final, sudden fracture of the remaining cross section. C. DISTORTION FAILURES Distortion Failure occurs when a structure or component is deformed so that it a) No longer can support the load it was intended to carry. b) Is incapable of performing its intended function, or c) Interferes with the operation of another component. Distortion failures can be either plastic or elastic, and may or may not be accompanied by fracture. There are two types of distortions, size distortion, which refers to change in volume, and shape distortion (bending or warping). Distortion failures are considered to be self evident body in collision. D. WEAR FAILURES Wear is a surface phenomenon that occurs by displacement and detachment of material. Wear usually results in progressive loss of weight and dimensions over a period of time. alteration in or All mechanical components that undergo sliding rolling contact are subject to some degree of wear. Typically, components such as bearings, gears, seals, guides, piston rings, splines, brakes and clutches. Lubrication implies the intentional use of substance that reduce friction between contacting surfaces. Lubrication is a mitigating factor in wear, and thus lubricated and non-lubricated wear. E. FRETTING FAILURES Fretting is a wear phenomenon that occurs between two mating surfaces, it is adhesive in nature, and vibration is its essential causative factor. Fretting Characteristics: Fretting occurs at contacting surfaces that are intended to be fixed in relation to each other, but that actually undergo minute motion, called „Slip%, that is essentially produced by vibration. Common sites for fretting are in joints that are bolted, keyed, pinned, press fitted, and riveted, in osculating bearings, splines, couplings, clutches, spindles, and seals, in press fits on shafts and in universal joints, base plates, shackles and prosthetic devices. Prevention of Fretting: Fretting can be minimized or prevented by: a) Elimination or reduction of vibration, b) Elimination of slip, c) Lubrication, d) Surface separation, and e) Induction of residual stresses F. LIQUID EROSION FAILURES Erosion of a solid surface in a liquid medium without the presence of solid, and abrasive particles one of the mechanism of liquid erosion involves the formation and subsequent collapse of bubbles with in the liquid, which is called as „Cavitation%. When the liquid droplets collide with a solid surface at high speed, a form of liquid erosion called liquid impingement erosion occurs. Cavitation damage has been observed on ship propellers and hydrofoils, on dams, spillways, gates, tunnels and other hydraulic structures, and in hydraulic pumps and turbines. Liquid-impingement erosion has been observed on many components exposed to high velocity steam containing moisture droplets of large steam turbines. A form of liquid-impingement erosion, rain-evasion, frequently damages aerodynamic surfaces of air-craft and missiles when they fly through rainstorms at high subsonic or supersonic speeds. G. STRESS CORROSION CRACKING Stress corrosion cracking is a mechanical environmental failure process in which sustained tensile stress and chemical attack combine to initiate. Failure by stress-corrosion cracking occurs by simultaneous action of chemical environment and tensile stress of the metal part. Some times the presence of hydrogen in a metal, may result in cracking. Sources of stresses in Manufacture: The principal sources of local/locked up stress in manufacture include: a) Thermal processing b) Stress raises c) Surface finishing treatment, and d) Fabrication Thermal Processing: Most common source of thermal processing heat treatment suen as welding, cold working drawing etc., quenching H. LIQUID METAL EMBRITTLEMENT Liquid Metal Embrittlement (LME) is the decrease in strength or ductility of a solid metal that is caused by contact with a liquid metal. Liquid metal embrittlement results in either: a) A decrease in tensile elongation prior to failure, or b) Fracture plastic deformation at stress level below normal yield. I. HYDROGEN EMBRITTLEMENT Depending on the type of hydrogen/metal interaction, hydrogen damage of metal manifests itself in one of several ways. Types of Hydrogen Damage: The embrittlement occurs only in specific alloys under specific conditions are: 1. Hydrogen embrittlement 2. Hydrogen-induced blistering 3. Cracking from precipitation of internal hydrogen 4. Hydrogen attack 5. Cracking from hydride formation J. ELEVATED TEMPERATURE FAILURES At elevated temperatures metals undergo dimensional changes with time are creep. The conditions of temperature, stress, and time under which creep and failures occur depending on the metal or alloy, its micro structure, and the on the service environment. stress-rupture. The principal type of elevated temperature combinations of these. mechanical failure are creep and stress- rupture, low cycle or high cycle fatigue, thermal fatigue, tension overload. K. FAILURES RELATED TO CORROSION which is the unintended destructive chemical or electrochemical reaction of a material with its environment, frequently leads to service failures of metal parts or reders them susceptible to failure by some other mechanisms. All corrosion reactions are electro chemical in nature and depend on the operation of electre chemical cells at the metal surface. The rate, extent and type of corrosion that can be tolerated on the specific application, whether the observed corrosion behavior was normal for the metal used in a given service conditions helps determine what corrective action, if any, should be taken. Factors that Influence Corrosion Failures: Several factors, and the possibility of interactions among them, must be considered by the failure analyst. a) In determining whether corrosion was the cause of, or contributed in some way to, a failure, and b) In devising effective and practical corrective measures. The type of corrosion, its rate and the extent to which it progresses are influenced by the nature, composition and uniformity of the environment and metal surface that is in contact with that environment. Other factors that have major effects on the corrosion process include temperature and temperature gradients at the metal environment interface, the presence of crevices in the metal part or assembly, relative motion between the environment and the metal part, and the presence of dissimilar metals in an electrically conductive environment. Failure Analysis Failure analysis is performed by systematically examining, testing and analyzing the failure, starting with gathering information about the component, its application and history, followed by a detailed visual examination, then nondestructive testing (magnetic particle test, dye penetrant test, low magnification stereoscope, etc.), leading to high magnification examination and destructive testing (such as: scanning electron microscopy (SEM), sectioning the sample for Metallographic micro analysis, Hardness testing, Chemical Analysis, Mechanical testing, etc.). A typical forensic metallurgical failure analysis includes the following eight steps: 1. Collect failed component background information and service history. 2. Perform a visual examination of failed and related components in the asfailed condition. Perform low magnification examinations using a stereomicroscope to locate critical areas for further analyses or testing. Take dimensional measurements as necessary. 3. Analyze the fracture or degraded surfaces utilizing a Scanning Electron Microscope (SEM) at high magnification. 4. Using the SEM, determine the failure mode and origin/initiation site. Investigate the initiation site for unusual conditions or contributing factors. Identify and characterize the failure mechanism (fatigue, embrittlement, overload, type of corrosion, etc.) Investigate for unusual stress risers. 5. Select, prepare, examine and analyze the cross-section microstructure in the region of failure/fracture initiation. Analyze conditions of manufacturing reflected in microstructure and investigate potential flawed conditions. Investigate material quality and heat treat conditions. 6. Perform a chemical composition analysis of the failed component (alloy and impurities), and coatings or platings. 7. Perform mechanical and other testing (hardness, strength, toughness, etc.). 8. Analyze all gathered evidence and test results to formulate an engineering opinion and conclusion. 9. Through a careful extensive forensic examination and evaluation of the evidence gathered from the above analysis, the pieces of the puzzle are fit together in a conclusive manner and a root cause of failure is identified. All evidence and forensic failure analysis results are photographically documented and presented in a report, which interprets and explains each finding in a clear and concise format. 3. Current challenges in handling Cyber Crimes and role of Multimedia Forensics ? Ans : Challenges in handling Cyber Crimes Cyber security poses bigger threat than any other spectrum of technology. Cyber criminals have already started abusing technology controlled devices for propelling cyber-crimes such as frauds and thefts. With technology protocols, still being developed and evolving at a gradual pace, it is very difficult to avoid such cyber-attacks. IoT plays a dramatic role in shaping the future of technology in India. With IoT now becoming backbone of various ventures, firms, organization and even basic ways of living, it is worrying that India has no dedicated law for IoT and some kind of guidance can be referred from the Information Technology Act, 2000 (IT Act, 2000). The Digital India initiative is driving our country towards a digitized life where the existence will highly depend on elements like cloud computing, 5G in telecom, e-Commerce etc. it is imperative to keep a check on loose ends. Few challenges that the technology space faces in cyber security are the following: - Digital Data Threat: Growing online transactions generate bigger incentives for cybercriminals. Besides, establishments looking to mine data—for instance, customer information, results of product surveys, and generic market information—create treasured intellectual property that is in itself an attractive target. - Supply Chain Inter-connection: The supply chains are increasingly interconnected. Companies are urging vendors and customers to join their networks. This makes a company’s security wall thin. - Hacking: This action is penetrating into someone’s system in unauthorized fashion to steal or destroy data, which has grown hundred folds in the past few years. The availability of information online makes it easier for even nontechnical people to perform hacking. - Phishing: The easiest to execute and can produce the results with very little effort. It is the act of sending out Fake emails, text messages and create websites to look like they're from authentic companies. These challenges can be under surveillance and methodical steps can be taken to avoid such malpractices. To solve data theft problem, online space must regulate the use of data and clearly indicate when information will be shared provided by the users. The user can then choose to opt out, leaving personal information restricted to the space for which it was deliberated. When software online contains bugs or viruses, it is fairly easy for cyber criminals to gain personal information. Large technology firms should collaborate and create solutions that to increase security for their customers. Security controls need to move outward, beginning at the application level where such frauds can be caught easily. When there are no unified monitoring methods, firms become vulnerable. However, when every network has monitoring that detects changes, data can be protected. Multimedia Forensics Multimedia Forensics includes a set of scientific techniques recently proposed for the analysis of multimedia signals (audio, videos, images) in order to recover probative evidences from them; in particular, such technologies aim to reveal the history of digital contents: - identifying the acquisition device that produced the data, - validating the integrity of the contents, - retrieving information from multimedia signals. The term “forensic” comes directly from the legal environment, where today the traditional understanding of evidence is changing and most prosecutors, lawyers and judges deal with digital evidences, that are intended to include all forms of evidence created, manipulated, stored, transmitted by means of digital devices (such as computers, telephone systems, wireless communication systems, networks as internet, mobile telephones, smart cards, navigation systems, and many others). Whereas the so called Computer Forensics considers the use of scientific methods to extract such digital data by devices involved in criminal scenarios, the Multimedia Forensics, as a second phase, applies scientific methods for the analysis of the contents. The usual methodology is based on the idea that inherent traces (like digital fingerprints) remain in digital content, both during the creation process and any other successive processing; hence, by extracting some digital fingerprints from the data and analyzing their properties, it is possible to have some knowledge on the life cycle of the data. More specifically, for source identification, forensic algorithms assume that the acquisition device leaves specific traces due to its intrinsic characteristics (for example sensor noise, lens distortion, etc). Basing on such intrinsic characteristics, statistical tests are able to distinguish between computergenerated images, images produced by a scanner and those obtained by a digital camera; distinguish among certain camera models; distinguish which specific camera was used for taking a picture. Similarly, tamper detection algorithms try to verify the integrity of the content, by assuming that different processing algorithms leave identifiable traces (for example the JPEG blocking artefacts); or that the traces introduced by the acquisition device are altered due to tampering; or that some inconsistencies of scene characteristics are introduced by tampering (for example inconsistencies in light condition). Finally, Multimedia Forensics considers to exploit a number of signal enhancement procedures (as noise suppression or distortion compensation) in order to attain a higher degree of intelligibility of the data. Furthermore, techniques for information retrieval are applied to multimedia signals, in order to acquire information from visual and audio files, including object colour analysis, pattern recognition, photogrammetric measurement of objects within the scene (for example footprints), anthropometric feature evaluation of people within the scene (for example height), speaker recognition.
