Heat transfer coefficient and thermal losses of solar collector and Nusselt number correlation for rectangular solar air heater duct with longitudinal fins hold under the absorber plate

An experimental investigation has been carried out for a series of system and operating parameters in order to analyze the effect of mass flow rate on heat transfer and Nusselt number characteristics in solar air heater. Experiments are performed at different air mass flow rates; varying from 0.012 to 0.016 kg/s, about hot summer days of Mai 2012. Hourly values of global solar radiation and some meteorological data (temperature, wind speed, relative humidities, etc.) for measuring days are obtained from the Biskra city of Algeria. The experiments encompassed the flow Reynolds number in the range 965.48–1301.4. Longitudinal fins were used inferior the absorber plate for an increase the heat exchange and render the flow fluid in the channel uniform. The effects of mass flow rate of air on the outlet temperature, Nusselt Number, Reynolds Number, Prandtl Number, the heat transfer in the thickness and length of the solar air collector were studied. For this effect was have created a new correlation correspondent of solar air collector with using fins it was written Nu = κ₀Re^1.36Pr^?0.68exp(0.342m)h ^[?0.018Pr].     

Securing physical layer using new chaotic parametric maps

Multimedia Tools and Applications - In this work, to overcome the flaws of standard chaotic maps we generated two new cascaded structures, 3D Cubic-Sine and 2D Cubic-Cat chaotic parametric maps,...     

The Microstructure,Texture and Mechanical Properties of Friction Stir Welded Aluminum Alloy

Russian Journal of Non-Ferrous Metals - The microstructure and texture of 7075-T6 FSW weld with optimal parameters are investigated using optical microscopy, electron back scatter diffraction and...     

A Robust Control Scheme Based on Sliding Mode Observer to Drive a Knee‐Exoskeleton

In this paper, a robust control scheme to drive a knee‐exoskeleton has been designed to assist people with limited knee movement. Dynamic modeling and parameter identification of the “subject's lower limb‐exoskeleton” has been performed and a sliding mode observer (SMO) developed and integrated in the system's closed loop to provide velocity. Lyapunov's theory allows demonstration of the stability of the system. Experimental tests have been performed with the aid of five voluntary subjects, in sitting position, and during flexion/extension of the knee joint. The performance of the proposed control scheme is compared with those obtained using the classical proportional integrator derivative (PID) controller. These tests track the desired position and velocity trajectories with small tracking errors and evaluate the system's stability and system's robustness against the subject's parameters, variations, and external disturbances.     

A methodology to assess the availability of next-generation data centers

The Journal of Supercomputing - Cloud data center providers benefit from software-defined infrastructure once it promotes flexibility, automation, and scalability. The new paradigm of...     

Peptic hydrolysis of bovine beta‐lactoglobulin under microwave treatment reduces its allergenicity in an ex vivo murine allergy model

In this study, the in vivo allergenicity of bovine beta‐lactoglobulin (BLG) in peptic whey protein hydrolysates generated during microwave and conventional heating treatments was assessed. The allergenicity of the hydrolysates was explored by studying the reaction of the murine jejunum from previously immunised Balb/c mice to treated BLG in an Ussing chamber. Intestinal anaphylactic reactions after stimulation of the gut‐associated immune system are a good indicator of potential in vivo allergenicity of whey hydrolysates. Fifty‐two per cent of BLG was hydrolysed by pepsin after only 3 min of microwave irradiation at 200 watts (W), yet it remained intact under conventional heating. Far‐ and near‐UV circular dichroism spectra indicated significant changes in BLG secondary and tertiary structures with microwave irradiation at 200 W. Pepsin whey protein hydrolysates obtained with microwave irradiation at 200 W for 3 min did not stimulate secretion of chloride in the Ussing chamber, as shown by the intensity of the short current values recorded (27.86 μA cm^?2), compared to the conventional pepsin hydrolysates (68.21 μA cm^?2). This demonstrates the low allergenicity of whey protein hydrolysates generated in this manner. These results confirm that microwave treatment combined with peptic hydrolysis could be applied to produce low allergenicity milk peptides.     

Reversible and Irreversible Modulation of Tubulin Self‐Assembly by Intense Nanosecond Pulsed Electric Fields

Tubulin self‐assembly into microtubules is a fascinating natural phenomenon. Its importance is not just crucial for functional and structural biological processes, but it also serves as an inspiration for synthetic nanomaterial innovations. The modulation of the tubulin self‐assembly process without introducing additional chemical inhibitors/promoters or stabilizers has remained an elusive process. This work reports a versatile and vigorous strategy for controlling tubulin self‐assembly by nanosecond electropulses (nsEPs). The polymerization assessed by turbidimetry is dependent on nsEPs dosage. The kinetics of microtubules formation is tightly linked to the nsEPs effects on structural properties of tubulin, and tubulin‐solvent interface, assessed by autofluorescence, and the zeta potential. Moreover, the overall size of tubulin assessed by dynamic light scattering is affected as well. Additionally, atomic force microscopy imaging reveals the formation of different assemblies reflecting applied nsEPs. It is suggested that changes in C‐terminal modification states alter tubulin polymerization‐competent conformations. Although the assembled tubulin preserve their integral structure, they might exhibit a broad range of new properties important for their functions. Thus, these transient conformation changes of tubulin and their collective properties can result in new applications.     

RIP – A robust IP access architecture

This research is of the view that only tightly coordinated work among security components as we know them today including firewalls, traffic analysis modules, intrusion detection systems, antivirus remediation systems, etc., is likely to take us closer to a more effective solution against some security threats. A structured Robust IP (RIP) access architecture is described and its components are analyzed through the use of a proof of concept testbed. Examples of the use of RIP and the heuristics it implements are evaluated. We also compare RIP performance to existing work. We show that there are currently some tradeoffs that need to be made between accuracy and responsiveness. We believe that this collaborative communication style between the components represents a significant step in the direction of self-defending networks and innovation in the area.     

Appraisal and reporting of security assurance at operational systems level

In this paper we discuss the issues relating the evaluation and reporting of security assurance of runtime systems. We first highlight the shortcomings of current initiatives in analyzing, evaluating and reporting security assurance information. Then, the paper proposes a set of metrics to help capture and foster a better understanding of the security posture of a system. Our security assurance metric and its reporting depend on whether or not the user of the system has a security background. The evaluation of such metrics is described through the use of theoretical criteria, a tool implementation and an application to a case study based on an insurance company network.