Survey of American (USA) Gasolines (2008)

The regulations for gasoline's content vary depending on the time of year and physical location within the United States while the refinery and distribution system mixes product batches; this results in variability of content. ASTM E1618 requires both the aromatic and alkane EIP patterns of gasoline to compare with references. A survey was conducted by collecting gasoline from Florida to Oregon, from 85 to 93 octane. Samples were analyzed in accordance with ASTM E1618 in various states of evaporation. The range of differences found in the 90% evaporated alkane EIPs is presented and showed a continuum of response when the n-alkane response was compared with the branched alkane response. Similarly, the ratio of the alkane EIP to the aromatic EIP also showed a continuum of response at the 90% evaporated state. Gasoline samples with unusual characteristics are also discussed.     

构建中心城区社区消防管理体系的思考

大城市的中心城区往往火灾多发,是消防管理中的薄弱环节。因此,加强社区消防管理,依靠全社会的力量,构建与中心城区特点相适应的社会消防管理体系,在当前显得十分重要和迫切。     

The influence of the type of accelerant, type of burned material, time of burning and availability of air on the possibility of detection of accelerants traces

The presented research consisted in a series of field experiments and laboratory analyses of obtained samples. Their aim was to investigate how different factors influence the possibility of identification of accelerant traces in conditions that are as similar as possible to those of real fires. The studied factors were: type of burned material, type of accelerant, length of time between lighting and extinguishing of fire and the air availability level. The obtained results show that, among investigated factors, the type of burned material has the greatest influence. The other factors, with regard to their influence, could be ranked in descending order as follows: ‘other’ (hard to determine and regulate factors), type of accelerant, time of burning and air availability. ‘Other’ factors include arrangement of the burned material and dispersion of the accelerant.     

The Effects of Burning and Mold Growth on the Chemical Composition of Firelog Fuels

Firelogs consist of a cellulosic material, such as sawdust or wood particles, and a combustible binder (fuel). Historically, the fuel typically consisted of a petroleum‐based (paraffin) wax; however, some manufacturers now include vegetable oils in their firelog fuels. To determine fuel composition, fuels from various brands of firelogs were extracted and analyzed by high‐temperature gas chromatography–mass spectrometry (HTGC‐MS) and a GC‐MS with a polar column specific for the analysis of fatty acid methyl esters (FAMEs). Firelogs were also burned, allowed to grow mold, and analyzed by GC‐MS to determine the effects that burning and mold growth have on firelog fuel composition. Mold did not tend to preferentially degrade any of the fatty acids. Burning caused a decrease in the relative amount of all of the fatty acids present in the vegetable oil fuel, with a greater effect on unsaturated fatty acids than saturated ones.     

The Effect of Skin Debris on Gunshot Residue Sampling and Detection

These experiments were designed to determine whether skin debris (desquamated epithelial cells and apparent skin oils) affects gunshot residue (GSR) particle detection on the sticky tape lift samples prepared for scanning electron microscopy (SEM). A dabbing experiment showed that GSR particles accumulate not only on the adhesive surface of the sampler, but also on the epithelial cell surfaces. Samplers were loaded with target GSR followed by dabbing 30 times on the back of a hand. Backscatter electron images were taken at 20 kV and for some at 30 kV of the same areas. The samplers were then treated with a sodium/calcium hypochlorite solution (bleach) to remove skin debris and again imaged in the SEM. Comparison of these images shows more GSR particles will likely be revealed at 30 kV than 20 kV and more particles revealed by the bleach treatment in an automated SEM system.     

The forensic examination of structural fires in Victoria,Australia: Decision-making processes and impact on judicial outcomes

There is a body of published research that has evaluated the contribution of forensic science to the criminal justice system, but many disciplines of forensic science remain unexplored in this regard. The aim of this study was to examine the contribution that forensic fire examination services provide to criminal investigations and court processes in arson cases. Forensic fire examination services differ in a number of ways to the disciplines covered in previous research on the impact of forensic evidence on justice outcomes. Forensic fire examinations involve a combination of scene examination and laboratory analyses, and the results can provide critical evidence of whether an incident that has occurred is a criminal offence (i.e. whether a fire has occurred as the result of an act of arson). Forensic fire examination is also a discipline that has faced challenges and undergone development in recent decades regarding its scientific basis and the issue of contextual bias. In this study, data were collated for 273 structural fires that were examined by the forensic fire services in Victoria, Australia. In this jurisdiction, scene and laboratory forensic services are delivered within short time frames with a focus on providing impartial scientific and investigative services to assist criminal investigations conducted by police. The current dataset was highly skewed in terms of criminal justice outcomes and was not suitable for conducting the planned statistical analyses. Nonetheless, the pattern of findings obtained suggested that the inclusion of forensic evidence which supported the prosecution of arson may be associated with an increased likelihood of suspects being charged and defendants found guilty. Examination of the decision-making process of the forensic fire examiners has provided insight into the variety of evidence that is considered by forensic experts in reaching the important conclusion about the origin and cause of structural fires.     

Sampling and recovery of ignitable liquid residues (ILRs) from fire debris using capillary microextraction of volatiles (CMV) for on-site analysis

A new, fast, and ultra-sensitive headspace sampling method using the Capillary Microextraction of Volatiles (CMV) device is demonstrated for the analysis of ignitable liquid residues (ILRs) in fire debris. This headspace sampling method involves the use of a heated can (60°C) to aid in the recovery of volatile organic compounds (VOCs) from medium and heavy petroleum distillates. Our group has previously reported the utility of CMV to extract gasoline at ambient temperature in less than 5 min in the field. This work evaluates the recovery and analysis of low mass loadings (tens of ng) of VOCs from charcoal lighter fluid, kerosene, and diesel fuel. Nonane, decane, undecane, tridecane, tetradecane, and pentadecane were selected for evaluation of recovery to represent these ILR classes. The face-down heated can headspace sampling technique was compared to the previously reported, non-heated, paper cup headspace sampling technique. Mass recovery improvements of 50%–200% for five of the six target compounds in diesel fuel were achieved compared to the non-heated sampling method. The average relative standard deviation (reported as % RSD) between the replicate trials decreased from an average of 28% to 6% when using the heated can method. Ignitable liquids were spiked onto burned debris in a live burn exercise and sampled using the heated can and paper cup headspace sampling techniques. The heated sampling technique reported here, for the first time, demonstrates an effective extraction method that when coupled to a portable GC–MS instrument allows for a sampling and analysis protocol in the field in less than 30 min.     

Wrongful convictions and claims of false or misleading forensic evidence

The results are reported of a study to examine case factors associated with 732 wrongful convictions classified by the National Registry of Exonerations as being associated with “False or Misleading Forensic Evidence.” A forensic error typology has been developed to provide a structure for the categorization and coding of factors relating to misstatements in forensic science reports; errors of individualization or classification; testimony errors; issues relating to trials and officers of the court; and evidence handling and reporting issues. This study, which included the analysis of 1391 forensic examinations, demonstrates that most errors related to forensic evidence are not identification or classification errors by forensic scientists. When such errors are made, they are frequently associated with incompetent or fraudulent examiners, disciplines with an inadequate scientific foundation, or organizational deficiencies in training, management, governance, or resources. More often, forensic reports or testimony miscommunicate results, do not conform to established standards, or fail to provide appropriate limiting information. Just as importantly, actors within the broader criminal justice system—but not under the purview of any forensic science organization—may contribute to errors that may be related to the forensic evidence. System issues include reliance on presumptive tests without confirmation by a forensic laboratory, use of independent experts outside the administrative control of public laboratories, inadequate defense, and suppression or misrepresentation of forensic evidence by investigators or prosecutors. In approximately half of wrongful convictions analyzed, improved technology, testimony standards, or practice standards may have prevented a wrongful conviction at the time of trial.     

警察开枪射击的适法情形与最小武力原则——德国的制度逻辑与借鉴意义

何时开枪、开枪限度如何是警察枪支使用制度中的核心议题。对此,德国法不仅通过“开枪目的”和“行为罪质”(重罪或轻罪)来限定准许开枪的适法情形,还根据射击动作的各个环节动态地分解最小武力原则。德国制度设计的内在机理为解决我国警察实践中不敢用枪、过度用枪问题提供了有力的理论支撑。其一,《人民警察使用警械和武器条例》第9条列举的14种开枪适法情形应在与刑法关联的意义上理解,即应将相对应的犯罪构成要件导入到枪械使用的要件判断中去。其二,可以开枪的适法情形包括但不限于上述《人民警察使用警械和武器条例》第9条明文例举的14种情形。根据立法者本意,该条兜底条款“法律、行政法规规定可以使用武器的其他情形”,是指所有为《刑法》所规定,最低刑在3年以上的犯罪。其三,中德制度之比较为全面理解我国落实最小武力原则的相关制度以及多个关键的不确定法律概念提供了广阔视角与智识资源。     

From Brigade to Service: An Examination of the Role of Fire and Rescue Services in Modern Local Government

Over the last ten years, local government modernisation and the growth of community safety agendas have called for change in the public sector at a local level. This has been typified by partnership work, improvement and inspection and community governance. The fire and rescue services, despite some initial cultural difficulties, haveworked hard to adapt themselves to modern local government, for example through community fire safety work, which is presented as a case study. However, the culmination of the modernisation project, Comprehensive Area Assessment, does not favour the fire and rescue service, and to an extent excludes them from its formula. In this light, it seems that there is little incentive for the Fire Service to continue its modernising trajectory.