Adhesive tape analysis: establishing the evidential value of specific techniques

This study investigated the evidential value of specific methods of analysis for packaging tapes and clear adhesive tapes available in Australia. Fifty-eight adhesive tapes were analyzed using a wide range of optical, physical, and chemical techniques. The results were collated for the purpose of creating an Australian database of adhesive tapes, which would be of assistance in criminal investigation. Each technique was evaluated for its discriminating power, both for comparative purposes and for the identification of adhesive tapes by comparing unknown samples with the database. The combined discriminating power of the techniques applied is very high. It is possible to individually identify the source of an unknown adhesive tape sample in many instances by searching the database. It is also possible to form an opinion on the significance of a failure-to-discriminate result in comparative casework. Further work is still needed to expand and update the database, as well as compiling data on the relative market share of various products.     

Enhancing contrast of fingerprints on plastic tape

Many of the currently available fingerprinting methods have limited ability to visualize fingerprints on plastic tape without expensive equipment or significant handling of the sample. This is especially true for visualizing fingerprints on black electrical tape. This study sought a hands-off method to produce easy visualization of fingerprints on different types of plastic tape, including black electrical tape, without the need for expensive equipment. The methods selected were to sublime disperse dyes into the tape, both with and without the fuming of cyanoacrylate, everywhere except for where the fingerprint was applied. The resulting color contrasts provided enough differentiation to visualize fingerprints on plastic tape under ambient light. Sequential fuming with cyanoacrylate followed by disperse dyes provided the best visualizations on all tapes, and cyanoacrylate followed by disperse yellow 211 clearly visualized fingerprints on black electrical tape.     

论"家庭型"共同受贿犯罪若干疑难问题

家庭成员共同受贿是当前受贿犯罪的重要表现形式,在刑法理论和司法实践中都存在较多争议,论文在考察“家庭型”共同受贿犯罪理论的基础上,对“家庭型”共同受贿的形式进行了详尽的分析,并探讨共同受贿犯罪数额的认定问题。     

Paint and tape: collection and storage of microtraces of paint in adhesive tape

The collection and preservation of microtrace evidence with the aid of an adhesive tape is a method of choice in forensic science. This technique is rapid and easy and allows the concentration of microtraces on a carrier, which facilitates further investigations in the laboratory. Adhesive tapes are currently used to secure microtraces of fibers and glass, but hardly for traces of automotive paint and other lacquers for fear of interference with the analysis of binders. A collection of automotive paint consisting of original and repair lacquers collected by tape has been evaluated. After various times of storage within the tape, these samples were compared with untreated references by microscope FT-IR and microspectrophotometry (MSP). Another set of paints was collected in 1984, stored within the tape until 1995, and examined the same way. About 170 layers of lacquer with various types of binder were examined. With the exception of one clear lacquer no difference between treated samples and references was detected. This small difference observed could be correlated to the exposure to xylene (extractant) and was not caused by the storage within the adhesive tape.     

胶带的红外光谱检验

目的建立胶带的种类检验、方法。方法应用傅利叶显微红外光谱仪,分别对胶带的胶质、基质(基材)及整体(胶质和基质同时存在)进行检测分析。结果不同种类胶带,红外吸收图谱存在差异,相互间图谱匹配率不同。通过比对分析,可对不同种类的胶带进行鉴别。结论该方法检验胶粘带(胶带),检材用量少、结果准确,操作简便,具有很强的实用性。     

Identification of pressure-sensitive adhesive polypropylene tape

Identification of colorless, transparent, pressure-sensitive adhesive polypropylene tape (PP tape) was performed using infrared absorption spectrometry (IR) and pyrolysis gas chromatography mass spectrometry (Py-GC/MS) to determine the pressure-sensitive adhesive. Twenty different products of colorless, transparent PP tapes were examined in this study, and the results of analysis of IR spectra and Py-GC/MS were classified into twelve groups. In addition, the tapes were classified into 14 groups on the basis of IR measurement of release agent present in the backside. The results indicate that colorless, transparent PP tapes can be distinguished in terms of manufacturer, thereby demonstrating that this method of identifying colorless, transparent PP tape is effective. Moreover, the method was applied to the analysis of an actual forensic sample.     

Applicability of DNA analysis on adhesive tape in forensic casework

Adhesive tape is commonly used in crimes and is often the subject of forensic evaluation. DNA analysis of adhesive tape can provide DNA profiles of suspects. The object of this study was to evaluate the applicability of DNA analysis on adhesive tape samples in forensic casework. We retrospectively reviewed all cases involving adhesive tape or similar items received by our institute for DNA analysis during the past 11 years. From 100 forensic cases reviewed, 150 adhesive tape samples were examined. A total of 98 DNA profiles were obtained from these samples. Sixty-two of the profiles provided feasible case-relevant information. In conclusion, DNA profiling of adhesive tape samples can be useful in a variety of forensic cases.     

绝缘胶带的检验

目的建立常见绝缘胶带的种属检验和比对检验的方法。方法用傅立叶显微红外光谱仪检验绝缘胶带,并分析不同品牌胶带红外谱图的差异。结果对聚氯乙烯类和聚烯烃类绝缘胶带的检验快速而准确,通过比对分析还可对绝缘胶带进行比对认定。结论该方法对绝缘胶带检材用量少、检验准确率高,且操作简便,具有很强的实用性。     

A validation study for duct tape end matches

Fracture matches are considered to be the strongest association achievable in forensic examinations of glass, metal, wood, plastic, paint, tape, and other trace evidence. Despite being fairly routine examinations, few publications exist to support their admissibility in court. This study was designed, using duct tape as the fractured medium, to determine the validity and error rate associated with conducting end match (fracture match) examinations on this material. Five test designs, which varied either the source roll of tape or manner of separation (torn or cut) from the roll, were administered to four analysts with instructions to examine the assigned test sets for end matches. If an end match was not identified by the initial analyst, the entire test set was independently evaluated by the remaining three analysts. Results indicated that while tape grade did not hinder end match identification, the manner of separation could affect results.     

胶带粘面手印荧光显现剂的研发与应用

目的根据胶带粘面上潜在手印的特点,利用染料和潜手印的理化性质,研究开发胶带粘面手印荧光显现剂。方法在各种胶带粘面上显现潜在手印,并与常规的碳素墨水染色法进行比较。结果在长波紫外线照射下手印呈黄色明亮荧光,手印纹线清晰、连贯,基本不受手印遗留时间、客体表面颜色和性质的影响。结论胶带粘面上的汗潜手印和血潜手印用荧光显现剂显现效果优于碳素墨水染色法,在实际案件的侦破中有较好的应用前景。     

短波紫外反射照相显现胶带粘面潜在指印

目的研究胶带粘面上指印的提取方法。方法用短波紫外照相的方法对各种胶带粘面的指印进行拍照提取。结果从理论上解释了短波紫外照相拍照提取胶带粘面上指印的原理,从实践上为短波紫外照相法提取胶带粘面上指印提供技术方法和技巧。结论为胶带粘面指印的提取提供了一种新的方法。     

同色电工胶带的光谱成像技术检验

目的研究同种颜色电工胶带的区分方法。方法应用光谱成像技术对同色（选取红、黄、蓝、绿4种颜色）不同品牌的电工胶带进行区分。结果蓝色电工胶带的区分率最高,达到99.0%,红色、绿色、黄色样品的区分率相差不大,分别为94.3%、93.8%及93.3%。结论光谱成像技术可以实现同种颜色电工胶带的快速区分,从色度学角度为法庭科学领域电工胶带物证的区分提供了一种新的方法。     

A validation study for vinyl electrical tape end matches

Fracture matches are considered the strongest conclusion in the forensic examination of rigid materials, such as glass, metal, and paint. However, publications that support the fracture matching of polymeric films, such as tape backings, are limited. This study was designed to determine the validity and error rate associated with conducting end-match (fracture match) examinations on vinyl electrical tape. Test designs varied the source roll of tape, test preparer, or mode of separation from the roll. Results indicated that each affected the resulting severed tape ends. The analysts examining the end matches also had an effect on the results. Eight end matches in the study were not identified by the initial analysts and were considered inconclusive. One end match was misidentified, resulting in one false positive and an error rate of 0.049%. These results support a comprehensive physical and chemical tape comparison regardless of indications of an end match.     

Red tape and technology transfer in US government laboratories

The purpose of this paper is to gauge the effects of red tape and bureaucratization on the technology-transfer activities and effectiveness of government laboratories in the United States. Two central questions are addressed: Do laboratories involved significantly in technology transfer have more red tape than others? and Does the level of red tape have an effect on technology-transfer success? Objective and perceptual measures of red tape are used. Technologytransfer effectiveness is measured in terms of getting other organizations to adopt technology developed in the laboratory (“out the door” success) and of the commercial impact of transfers. Data are derived from questionnaire responses provided by directors of 276 federal- and state-government laboratories. Results indicate that laboratories involved in technology transfer do not have higher levels of red tape. Out-the-door technology-transfer success relates strongly to low degrees of perceived red tape, whereas high ratings for commercial impact are associated with actual low levels of red tape in acquiring project funding and lowcost equipment.     

Transfer of signatures with transparent pressure tape: Some experiments

This article presents a possible mode of forgery by transferring an original signature written either with a pencil or with an Eraser Mate pen by means of transparent pressure tape. It also describes the characteristics of this kind of forgery and proposes some methods of disclosing it.     

Examination of writings concealed by black pressure sensitive adhesive tape

Examination of concealed writing is often a challenge for forensic document examiners. Although the published literature describes many techniques, these are often only successful when the writing has been concealed by pencil, pen, or by spreading inks of different tint or by smearing of the writing with colored fluids. When black pressure sensitive adhesive (PSA) tape is used, these procedures are ineffective. The present report describes the use of a straight chain hydrocarbon to remove the PSA tape and allow a comparison of the concealed writing with that of a suspect. The use of the solvent had no observable effect on either the writing or the substrate. The procedure is rapid and easy to use and is also effective with other colored PSA tapes.     

Selection of an adhesive tape suitable for forensic fiber sampling

Five commercial adhesive tapes were tested for fiber uptake and saturation, for recovery and for ease of analysis. On the basis of the results, a high tack adhesive tape has been selected to be used for forensic fiber sampling. This adhesive tape is used as sampling material in two different micro trace kits. The first tape lifting kit is used mainly for the sampling of cars and the second is a 1:1 tape lifting kit for the collection of fibers on a corpse.     

Forensic utility of carbon isotope ratio variations in PVC tape backings

Forensic interest in adhesive tapes with polyvinyl chloride (PVC) backings (electrical tape) derives from their use in a variety of illicit activities. Due to the range of physical characteristics, chemical compositions, and homogeneity within a single roll of tape, traditional microscopic and chemical analyses can offer a high degree of discrimination between tapes, permitting the assessment of potential associations between evidentiary tape samples. The carbon isotope ratios of tapes could provide additional discrimination among tape samples. To evaluate whether carbon isotope ratios may be able to increase discrimination of electrical tapes, particularly with regards to different rolls of tape of the same product, we assessed the δ(13)C values of backings from 87 rolls of PVC-based black electrical tape (~20 brands, >60 products) Prior to analysis, adhesives were removed to prevent contamination by adhering debris, and plasticizers were extracted because of concern over their potential mobility. This result is consistent with each of these tapes having approximately the same plasticizer δ(13)C value and proportion of carbon in these plasticizers. The δ(13)C values of the 87 PVC tape backings ranged between -23.5 and -41.3 (‰, V-PDB), with negligible carbon isotopic variation within single rolls of tape, yet large variations among tape brands and tape products. Within this tape population, carbon isotope ratios permitted an average exclusion power of 93.7%, using a window of +/-0.3‰; the combination of carbon isotope ratio measurement with additional chemical and physical analyses raises the discrimination power to over 98.9%, with only 41 out of a possible 3741 pairs of tape samples being indistinguishable. There was a linear relationship between the δ(13)C value of tape backings and the change in δ(13)C value with the extraction of plasticizers. Analyses of pre- and post-blast tape sample pairs show that carbon isotope signatures are within 0.3‰ of pre-blast values, indicating that carbon isotope values are largely preserved during an explosion.