The application of photography in investigating fraud

The impact of fraud on the world economy is significant. As fraud has evolved it has become more organized and increasingly cyber-enabled and committed across borders of law enforcement jurisdictions. The technological demands facing fraud investigators are increasing. Yet, little attention has been given to how forensic photography can help tackle emerging crime types, like fraud. This study reviews literature surrounding forensic photography and provides an up to date and collective narrative. This article focuses on the advancements in photography and how imaging-science techniques can apply to a fraud investigation. Photographic practice plays a key role in many crime investigations but must embrace continual change to ensure that it remains relevant to modern policing. Fresh approaches are essential and practitioners must fully utilize new technologies and adapt to tackle the increasingly demanding scope of fraud types.     

Identification and Composition of Clasper Scent Gland Components of the Butterfly Heliconius erato and Its Relation to Mimicry

The butterfly Heliconius erato occurs in various mimetic morphs. The male clasper scent gland releases an anti-aphrodisiac pheromone and additionally contains a complex mixture of up to 350 components, varying between individuals. In 114 samples of five different mimicry groups and their hybrids 750 different compounds were detected by gas chromatography/mass spectrometry (GC/MS). Many unknown components occurred, which were identified using their mass spectra, gas chromatography/infrared spectroscopy (GC/IR)-analyses, derivatization, and synthesis. Key compounds proved to be various esters of 3-oxohexan-1-ol and (Z)-3-hexen-1-ol with (S)-2,3-dihydrofarnesoic acid, accompanied by a large variety of other esters with longer terpene acids, fatty acids, and various alcohols. In addition, linear terpenes with up to seven uniformly connected isoprene units occur, e. g. farnesylfarnesol. A large number of the compounds have not been reported before from nature. Discriminant analyses of principal components of the gland contents showed that the iridescent mimicry group differs strongly from the other, mostly also separated, mimicry groups. Comparison with data from other species indicated that Heliconius recruits different biosynthetic pathways in a species-specific manner for semiochemical formation.     

高压下CL-20拉曼光谱和红外光谱相变研究

为了更好地认识和了解CL-20晶体结构演变规律和相变行为,利用金刚石对顶砧超高压实验技术,在0~50GPa下,研究了高压下ε-CL-20的原位拉曼光谱和红外光谱。结果表明,CL-20晶体在整个加压过程中存在两个相变,第一个相变发生在4.2~7.5GPa,认为是ε相到对称性更低的γ相转变,相变产生的原因是在压强的作用下,笼环外的硝基方向发生改变,电子云密度重置导致的分子构型转变;第二个相变发生在14.2~18.9GPa,属于γ相到ζ相的晶体结构转变;卸压后,拉曼和红外光谱恢复常压状态,表明CL-20晶体在研究压强范围内的相变过程是可逆的。     

氟橡胶的红外光谱研究

采用红外(IR)光谱,包括一维红外光谱、二阶导数红外光谱、四阶导数红外光谱和去卷积红外光谱对氟橡胶(FKM)的分子结构进行了研究。试验发现:氟橡胶的红外吸收模式主要包括CH2不对称伸缩振动模式(νasCH2-FKM)、CH2对称伸缩振动模式(νsCH2-FKM)、CH2弯曲伸缩振动模式(δCH2-FKM)、CF2不对称伸缩振动模式(νasCF2-FKM)、CF2对称伸缩振动模式(νsCF2-FKM)和CFCl伸缩振动模式(νCFCl-FKM)等。研究发现:氟橡胶的去卷积IR光谱的谱图分辨能力要优于相应的一维IR光谱、二阶导数IR光谱和四阶导数IR光谱。此研究拓展了IR光谱在氟橡胶结构及应用研究的范围。     

Multilayer thermal object identification in frequency domain using IR thermography and vector fitting

This paper deals with the identification of the thermal parameters of multilayer objects using the concept of thermal impedance. In order to perform such identification, temperature evolution in time is obtained by an infrared camera after power excitation is applied in the investigated structure. Infrared thermography offers the advantage of being a noncontact temperature detection and measurement method. In many practical cases, it is impossible to use contact temperature measurements. Typically, the power in the form of a step function is applied. In order to calculate the thermal impedance of an object, temperature and power are converted into the frequency domain using the Laplace transform for s = jω. Then, the poles of the thermal impedance are identified using vector fitting, which allows calculating the thermal impedance as a sum of partial fractions. This corresponds directly to the Foster network of a thermal object. In addition, the vector fitting method offers much better convergence in comparison with other methods using the polynomial rational approximation of thermal impedance. A considerable improvement of the numerical Laplace transform in high frequency range is proposed. In this approach, the variable s = jω is replaced by , and then, the integration result is corrected by the Taylor series. It leads to a kind of filtering of the temperature signal.     

Synthesis,thermal stability and unknown properties of Fe1–xAlxVO4 solid solution

A continuous solid solution Fe_1-xAl_xVO₄ was synthesized by conventional ceramic method and characterized by DTA, XRD, IR, UV–vis/DRS and Mössbauer spectroscopy. Fe_1-xAl_xVO₄ crystallizes in a triclinic system and is isostructural with FeVO₄ and AlVO₄. With increasing content of Al³⁺ ions substituted for Fe³⁺ in the matrix structure of FeVO₄ a contraction of crystal lattice was observed, accompanied by shifts of IR absorption bands towards higher wavenumbers and shifts of UV absorption bands towards shorter wavelength. On the basis of the results of UV–vis investigations, the band gap energies were calculated. The solid solution sample of composition Fe_0.67Al_0.33VO₄ was found to have the highest melting point from among all examined samples, which equals to 870?°C. Moreover, the solid product of incongruent melting of Fe_1-xAl_xVO₄ for 0.75?>?x?≥?0.5 is Fe_1-xAl_xVO₄ solid solution, richer in iron. On the grounds of Mössbauer investigation, the partition of iron and aluminum ions over three accessible crystallographic sites was established. Fe_0.5Al_0.5VO₄ sample was successfully used as a reactant for Fe₄Al₄V₁₀W₁₆O₈₅ preparation.     

Optical and thermo-mechanical properties of fine-grained transparent yttria ceramics fabricated by hot-press sintering for infrared window applications

In this work, highly transparent yttria ceramics Φ?=?55?mm in size were fabricated by a hot-pressing method with 1 at.% ZrO₂ or 12 at.% La₂O₃ as a sintering additive. For a 4-mm-thick specimen doped with ZrO₂, the in-line transmittance reaches 71.1% at 400?nm and 80.9% at 1100?nm, and the transmittance of the La₂O₃-doped specimen is comparable to that of the ZrO₂-doped specimen. By means of the relatively low sintering temperature of 1600?°C, the present samples exhibited very fine microstructures (<2?μm), giving rise to excellent mechanical strength levels (～200?MPa). With regard to the 1 at.% ZrO₂-doped specimen, the combination of high strength and high thermal conductivity (～10 W/m?K) substantially improved parameters related to the thermal shock resistance. The results of this study indicate that the hot-pressed transparent yttria ceramic doped with 1 at.% ZrO₂ is optically, mechanically, and thermally suitable for high-temperature IR window applications.     

Investigation of structural,optical, and magnetic properties of Nd-doped Sr2SnO4 Ruddlesden Popper oxide

The samples of Sr_2-xNd_xSnO₄ with x = 0, 0.01, 0.02, 0.04, 0.06, and 0.10 were synthesized by a high-temperature solid-state ceramic route. Rietveld refining of X-ray diffraction results showed that all the synthesized compositions are single phase under tetragonal crystal structure. The presence of functional group and local structure has been studied using FTIR and Raman spectroscopy, respectively. XPS study of samples showed the presence of oxygen vacancy and interstitial oxygen in the sample. Optical band gap of samples analyzed by UV-Vis spectra gradually increases with dopant concentration, and Photoluminescence (PL) spectroscopy study showed most intense emission around 1064 nm. Room-temperature magnetic hysteresis curve in sample SSN2 showed ferromagnetism, slowly decreasing with Nd and becoming antiferromagnetic for higher compositions. Utilizing the absorption state observed in PL as metastable state makes it promising candidate for laser and IR detector application and the ferromagnetic/antiferromagnetic nature of sample makes it suitable candidate for spintronics device applications.     

环氧树脂水性化新方法及其涂料研制

用甘氨酸改性环氧树脂,使其成为具有亲水性的树脂,并成功制备了系列不同固含量稳定的水性环氧乳液。性能测试结果表明,制得的水性环氧树脂在有机溶剂中的溶解性变差,在碱性水溶液中的溶解性增强,作为水性环氧涂料,其固化物具有优良的涂膜性能。     

New biosorbent materials for heavy metal removal: product development guided by active site characterization

Olive pomace wastes were used as precursors for the development of new biosorbents for heavy metals. Thermal and/or chemical treatments were addressed in terms of their effects on functional group properties and copper removal. Product development was guided by experimental characterization (potentiometric titrations, IR spectra, copper biosorption, total surface area) and theoretical modeling of acid-base properties. Olive pomace was characterized by negative charge due to dissociation of two weakly acidic sites (carboxylic and phenolic). After thermal treatment, a char-like material was obtained, characterized by basic sites with positive charge in the acidic pH range. Copper biosorption properties of this material were improved with respect to olive pomace due to the binding ability of pyrone-like sites. Both native and carbonized olive pomace samples were chemically treated by HNO(3). Experimental tests were performed according to factorial designs and analysis of variance was used to evaluate significant effects on copper removal of both oxidant concentration and temperature. Chemical treatment by HNO(3) of carbonized material developed negatively charged groups in the acidic pH range (carboxylic groups), but presented a decreased copper removal. Chemical treatment by HNO(3) of olive pomace without carbonization gave biosorbents with acid-base properties similar to those of native olive pomace, but with a significant increase of copper biosorption. Specific carboxylic-copper interactions indicated by IR spectra and increased surface area due to chemical treatment were simultaneously responsible for such improvement.