Synthesis and characterisation of 4-picrylamino-2,6-dinitrotoluene (PADNT): a new insensitive explosive

A chemoselective reductive method has been achieved for the preparation of 4-picrylamino-2,6-dinitrotoluene (PADNT), a new insensitive energetic material which has been characterised by spectral data and elemental analysis. Some explosive properties of the compound have also been determined and the results indicate that PANDT is quite safe to impact and friction.     

Heart instantaneous frequency (HIF): an alternative approach to extract heart rate variability

Our study focuses on a new method of estimating the heart rate variability (HRV) which does not require the use of electrocardiogram (ECG) R-wave detection. Contrary to the R-wave detection method which requires a sampling frequency higher than 100 Hz, the one proposed here can be used to calculate the HRV from an ECG signal sampled at a frequency of approximately 5 Hz with a relative mean error of 0.03. This new method is based on extracting the instantaneous fundamental frequency from the ECG. The method could be efficiently used to extract the HRV from an ECG measured for healthy subjects performing an exercise in which the HRV increases linearly with time, and for subjects with respiratory and cardiac problems. The overall error decreased as we low-pass filtered the HRV with lower cut-off frequencies. Moreover, it was shown that the method could be efficiently used to calculate the HRV from blood pressure measurements and to be robust to noise.     

Highly Sensitive Pulsed Digital Holography for Built-in Defect Analysis with a Laser Excitation

A highly sensitive method is presented for noninvasive defect analysis on thin structures with a Q-switched double-pulsed ruby laser with frequency doubling (347 nm). In our research we feature an all-optical arrangement, where a focused laser pulse derived from the same ruby laser (694 nm) acts as a built-in synchronous excitation source for digital holographic interferometry. The recordings are made with a CCD camera for capturing two holograms (two states of the specimen) corresponding to the two UV laser pulses with a short time separation (10-50 mus). Subtraction of the phase distribution in two digital holograms gives a fringe phase map that shows the change in deformation of the specimen between the recordings. The advantage of the proposed method is two fold. First, the use of a shorter wavelength results in a higher sensitivity. Second, owing to the induced synchronous built-in optical excitation, the specimen is not subjected to any external physical excitation devices. Experimental results are presented on identification and evaluation of defects in thin metal sheets.     

Long-term retention of injected barium-133 in man

Data are presented on the whole-body retention of 133Ba (half-life 10.74 y), over periods of up to 13 y after injection into six healthy male volunteers aged 25-81, and on their levels of biochemical markers for bone turnover. The results are relevant to propositions underlying the ICRP's current (Publication 67) and former (Publication 20) models of alkaline earth metabolism. The tracer was predominantly skeletal within weeks of the injection, as predicted in the current model. The mean retention accorded satisfactorily throughout with predictions based on the current model, but this accord does not necessarily validate the model, for two reasons. First, parameter values attributed to barium were influenced by data emerging during the early years of this study. Second, bone resorption rates in these subjects, as indicated by urinary markers, appear insufficient to explain the long-term reductions in skeletal retention which, in the present model, arise exclusively through this mechanism.     

Use of organic forms of selenium in nutrition of patients with gastrointestinal diseases

Selenium level was determined in sera of 27 patients including 15 patients with chronic gastrointestinal diseases and 12 patients with intestinal malabsorption after some kinds of stomach or small intestine resection. Deficiency of this trace element was found in 5 patients and suboptimal concentration in 4 patients in the first group and in 3 and 5 patients of second group respectively. Supplementation of patients with 45 mg of selenium organic form based on autolysis extract of selenious baker's yeast resulted in increase of selenium level in 23 (85%) patients including all of them with selenium deficiency or suboptimal level. It was concluded about high bioavailability of selenium in supplement studied. Perturbed intestinal absorption after surgical resection of stomach or small intestine may be considered as an indication for prophylactic taking of organic selenium form preparation.     

A study of the behaviour of a protected vessel containing LPG during pool fire engulfment

Theoretical and experimental investigations of various methods for protection against fires of vessels containing liquefied petroleum gases (LPG) (safety relief valves, intumescent fire retardant coatings, thermal isolation) have been carried out. A simple mathematical model has been proposed, which describes dependences of various parameters on time. These parameters are temperature, pressure and mass of LPG, temperatures of the vessel's walls and thermal protection layer. The case of total fire engulfment of the vessel with LPG was considered. Experiments have been executed, which were aimed on the investigation of the behaviour of vessels with LPG (50 l), equipped with protective devices during total fire engulfment. It was found out that the safety valve prevented an explosion of the vessels without any other protective measures. The presence of the intumescent fire retardant coating caused a significant delay in operation of the safety valve. A rather good agreement between the theoretical and experimental data was obtained. It has been revealed that the considered methods for protection of LPG vessels are promising in regard to prevention of explosions in these vessels at the fire engulfment.     

桦树汁酒的研制

本文采用桦树汁酒专用菌种，合理开发利用野生资源，生产适合市场需求，具有较高营养的天然食品，总结了桦树汁酒的生产工艺过程及质量标准。     

基于粒子群算法的矿山串级排水系统喂水泵调速技术研究

为解决矿山排水系统能耗高、效率低的问题，基于粒子群(PSO)算法开展了矿山串级排水系统优化设计。依据两台不同型号的离心泵串联运行理论，结合变频调速比例定律，推导主排水泵流量、扬程与喂水泵速度之间关系。以排水系统效率为优化目标，利用PSO算法对其进行极值寻优，以喂水泵额定转速对应的主排水泵和喂水泵电机电流、电压、功率因数以及喂水泵和主排水泵出口压力、流量为初始参量，通过限制迭代次数得到排水系统总效率理论极值，确定喂水泵最佳转速，并通过变频调速实验对其进行可行性验证。结果表明：所提出的喂水泵最佳转速确定方法具有较高的调速精度，可确保排水系统在高效工况区运行，进而达到节能降耗目的。     

矿用聚焦双频激电法电场扫描探测方法

为实现煤矿巷道超前探测,提出了一种基于双频激电法和电场扫描探测理论的矿用聚焦双频激电法超前探测技术。基于共线点电流源的电力线方程理论,推导煤矿巷道探测电场边界电力线方程算法;提出电场扫描探测策略,分析了电场扫描探测的实际分辨率;基于电介质边界条件,根据巷道地质结构模型推导电力线偏移向量求解公式,分析了地质异常体对电力线的影响。理论计算表明:通过连续改变探测仪各通道电流强度,探测电场扫描分辨率理论上可任意设定,实际探测由实际地质工况条件选定;地质异常体的存在会影响电力线分布,板状体的厚度越大或者围岩与板状体之间的电阻率比值越大或者板状体倾角越大,则电力线偏移向量横坐标与纵坐标的绝对值越大;通过电场聚焦和偏转扫描探测,可确定异常体的直径和方位。