Dual-detector for simultaneous time and energy measurements with superconductive detectors

The development of a superconductive detector for simultaneous measurement of energy and arrival time is reported. The detector consists of two superconducting tunnel junctions coupled through a passive network. The first junction operates in the quasi-particle regime and measures the energy absorbed by counting the total charge that tunnels. The second junction uses the DC Josephson effect to act as a fast discriminator for the onset of surplus current in the first junction. The feasibility of the detector is demonstrated through simultaneous time and energy measurements of 6 keV X-rays. A model of the detector is presented and numerical simulations show good correspondence with experimental data.     

Unilateral neonatal cystic disease of the kidney as first manifestation of tuberous sclerosis]

Traumatic optic neuropathy (TON) causes blindness of varied severity and occurs infrequently as a complication of closed head injury. A case is presented of TON that occurred in a patient who suffered complete T4 paraplegia from a motorcycle accident but in whom no severe head injury took place. In this case, high-dose intravenous methylprednisolone was begun for the spinal cord injury and repeated 24 hours later for the TON. Vision improved from near total blindness to 20/400 in the left eye (OS) and 20/130 in the right eye (OD). Two weeks later, however, the patient's vision suddenly worsened. Magnetic resonance imaging (MRI) using fat suppression confirmed a lesion along the optic nerve consistent with TON. A third course of methylprednisolone again led to improved vision. The steroids were then tapered orally over 2 weeks and the patient had no further relapses. Moderate to severely impaired vision of 20/ 400 OS and 20/130 OD continues to interfere with the patient's function and spinal cord rehabilitation program. It was concluded that a steroid taper was important in maintaining initial visual gains in this case. Awareness of TON and careful attention to the patient's clinical course can minimize deficit and maximize functional outcomes.     

Full- and half-square cell plans in urban CDMA microcellular networks

The Erlang capacity per cell and per unit area in urban code-division multiple-access (CDMA) microcellular environments is evaluated. Special emphasis is given to the effect of breakpoint distance and cell size on the system Erlang capacity. Two different cell plans are considered in which the communication between the base station (BS) and the mobile unit always occurs in a line-of-sight (LOS) condition: the full- and half-square cell plans. Our main result has been to obtain analytical expressions for the Erlang capacity, which are evaluated through a cell radius-normalization procedure, as a function of the breakpoint to the cell radius ratio (R/sub b//R/sub c/). This has allowed us to notice some important facts not previously reported in the literature. In particular, we observe that the Erlang capacity is a monotonically decreasing function of R/sub b//R/sub c/ and that close to the highest reuse efficiency is achieved for R/sub b/<0.7R/sub c/. Thus, given a breakpoint distance, higher Erlang capacity per cell can be achieved with greater cell radius. Or, equivalently, given a cell radius, higher system capacity can be achieved with smaller breakpoint distances; that is, with smaller base-station antenna heights and/or smaller frequencies. Also, we show that the capacity increase due to the BSs doubling or cell radius-reduction depends on the antenna heights, frequency of operation, and distance between streets. It ranges from 64 to 100%.     

Bronchial asthma: clinical course, serum IgE and skin tests

We studied a group of 38 asthmatic patients to correlate the clinical evolution with results of IgE in serum, RAST and skin tests. Results reveal that almost 70% of the studied patients present important positivity in skin tests or RAST which confirms that the majority of asthmatics have an allergic component in their etiology. The determination of IgE in serum showed not to be a definitive exam to confirm allergic etiology. Only 25% of asthmatic patients with severe evolution presented skin tests or RAST strongly positive.     

A molecular beam study of the tribological chemistry of dialkyl disulfides

Molecular beam studies carried out in ultrahigh vacuum show that dimethyl disulfide reacts with initially clean iron to evolve methane. The reaction is proposed to proceed via a methyl thiolate intermediate. Reaction ceases at 600 K, an effect that is proposed to be due to the surface being blocked by an overlayer of sulfur and carbon. Reaction recommences above 950 K as sulfur diffuses into the iron. The activation energy for the film-forming reaction is 52.5±2.1 kcal/mol, in good agreement with the activation energy for the growth of FeS films from dimethyl disulfide at higher pressures measured using a microbalance. A depth profile of the film grown in ultrahigh vacuum shows that the sulfur-containing film grows on a Fe+C underlayer. Similar molecular beam experiments with diethyl disulfide suggest the formation of an intermediate ethyl thiolate species which decomposes via a -hydride elimination reaction to evolve ethylene. The activation energy for film growth, in this case, is 60±2.4 kcal/mol. The results of tribological experiments using a pin and v-block apparatus are consistent with FeS forming the anti-seizure film.     

Cyberloafing in the workplace: mitigation tactics and their impact on individuals’ behavior

With the Internet permeating every aspect of daily life, organizations of all types are increasingly concerned about the degree to which their employees are cyberloafing by shirking their work responsibilities to surf the Internet, check e-mail, or send text messages. Although technological interventions against cyberloafing have been shown to be effective, they might be perceived by employees as an invasion to their privacy, and are expected to have repercussions on employee behavior and loyalty. The main objectives of this study are to (1) examine how the introduction of such technological interventions might affect employees’ emotions and fairness perceptions, and (2) understand the effect of the interventions on behavioral outcomes, i.e., employees’ intentions to cyberloaf and their loyalty to the company. We developed a justice-based framework that we empirically test using a field experiment composed of field surveys complemented with hypothetical scenarios describing new organizational initiatives to curb employees’ cyberloafing. Our findings suggest that technological interventions, although associated with perceptions of unfairness, are effective at controlling cyberloafing, albeit at the expense of employee loyalty. On the other hand, contrary to prior findings, we find that fairness perceptions of technological interventions, although reinforcing employee loyalty, are ineffective at curbing cyberloafing. These findings are especially enlightening in that they contradict a common belief that perceived fairness encourages employees, as a sign of their appreciation for this fairness, to curb their misuse of IT. The findings also help managers fine-tune their cyberloafing policies to achieve a long-lasting remedy to their employees’ cyberloafing while maintaining a necessary level of employee loyalty.     

Robust control of wind turbines based on fractional nonlinear disturbance observer

In order to assure maximum energy conversion, the angular velocity of the wind turbine rotor tracks a nominal profile depending on the wind speed. However, conventionally, wind flows present non‐differentiable components due to turbulence and gust winds, which affect the wind energy management. Thus, a fast and robust controller is required to induce such nominal regime for maximum energy transfer. A fractional‐order nonlinear disturbance‐observer (FNDOB) is proposed in this paper to cancel the non‐differentiable components of the wind speed, as well as dynamic uncertainties and other aerodynamic disturbances. The proposed FNDOB is based on continuous fractional sliding modes, assuring that disturbances and uncertainties are exactly compensated in finite‐time. A representative simulation study for a variable‐speed wind turbine is presented to show the reliability of the proposed scheme, and a comparative analysis with respect to a conventional linear disturbance observer based control is presented.     

Evaluation of MALDI-TOF/MS Technology in Olive Oil Adulteration

Adulteration of extra virgin olive oil (EVOO) by addition of other vegetable oils or lower-grade olive oils is a common problem of the oil market worldwide. Therefore, we developed a fast protocol for detection of EVOO adulteration by mass spectrometry fingerprinting of triacylglycerol (TAG) profiles based on MALDI-TOF/MS. For that purpose, EVOO TAG profiles were compared with those of edible sunflower oil and olive oil composed of refined olive oil and virgin olive oils. Adulteration of EVOO was simulated by addition of sunflower and mixture of refined olive oil and virgin olive oils at 1, 10 and 20% w/w. Results of mass spectrometry TAG profiling were compared with routinely assessed K values for identification of adulteration. MALDI-TOF/MS technology coupled with statistical analysis was proven as useful for detection of adulteration in EVOO at a rate down to 1%. In contrast, standard spectrophotometric methods failed to identify minor adulterations. In addition, the ability of MALDI-TOF/MS in detection of adulteration was tested on EVOO samples from different geographical regions. Results demonstrated that MALDI-TOF/MS technology coupled with statistical analysis is able to distinguish adulterated oils from other EVOO.     

Electrical,mechanical, and piezoresistive properties of carbon nanotube–polyaniline hybrid filled polydimethylsiloxane composites

The electrical, mechanical, and piezoresistive properties of ternary composites based on elastomeric polydimethylsiloxane (PDMS), carbon nanotubes (CNTs), and polyaniline (PANI) were studied and compared with those of binary PDMS–CNT composites. The presence of PANI affected the percolating network of the CNTs. At lower PANI concentrations (2.5 and 5%), the conductive network of the CNTs was constructively modified; this led to an enhancement in the conductivity in the sample containing 2% CNTs. A higher PANI content (7.5%) hindered the flow of main charge carriers through the composite. The piezoresistive response of the binary and ternary composites was studied by cyclic experiments under compression loads. In all of the samples, the electrical resistance increased monotonically up to a 10% strain. The reproducibility of the piezoresistive behavior in the binary and ternary composites provided evidence that the fillers could reversibly recover their initial position together with the PDMS chains without a significant displacement with respect to their original positions. The reduction of the piezoresistive sensibility by PANI addition was attributed to the displacement restrictions of the CNTs within the composite under pressure because of the volume exclusion of PANI particles; this maintained the probability of CNT contact and increased the possibility of the formation of new CNT conductive channels. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44780.     

An organic bioactive pro-oxidant behavior in thermal degradation kinetics of polypropylene films

Due to its versatility and low cost, polypropylene (PP) is one of the most widely used polymers in the world. However, since it does not easily degrade in natural environment, various methods have been studied to reduce its lifetime. The pro-degrading additives promote the polymer degradation process by accelerating the polymer degradation under heat and/or UV. Eco-one is an organic bioactive pro-oxidant additive that induces biodegradation when it is incorporated into a polymeric matrix by attracting microorganisms in the biotic phase. The aim of this work was to investigate the abiotic degradability of this organic bioactive pro-oxidant additive in PP films. Thermal oxidation studies of the specimens were carried out to investigate the abiotic degradability. We analyzed compositions of PP films containing 1, 3, and 5% Eco-one by mass. These films were characterized by thermogravimetric analysis to calculate the activation energy (E _α) and to estimate their lifetime. Differential scanning calorimetry was conducted to provide oxidative induction time. The samples were then aged at 80 °C and characterized by Fourier transform infrared spectroscopy to obtain the carbonyl index (CI). Compositions containing 1% Eco-one additive showed the optimal composition with lower activation energy, and shorter predicted lifetime, suggesting easier thermal degradation. Furthermore, high CI was also observed in samples containing 1% additive, indicating thermodegradation for this composition.