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In recent years, laser micromachining has made impressive gains in terms of accuracy, scalability and surface finish. Moreover, the availability of femtosecond lasers yields ablation without melting. Surfaces processed in this fashion exhibit less structural damage and are expected to have a higher damage thresholds. In this paper we will review several case studies of laser-microfabricated THz components. These will include corrugated waveguides for narrowband and quasi-optical mirror-like structures for broadband THz applications.

In this paper, a stabilization problem of angular positions is considered for the twin rotor electromechanical system under parametric uncertainties and the presence of cross-couplings between rotors. The procedure of block synthesis of nonlinear local feedbacks and discontinuous controls is developed. This procedure allows satisfying the project restrictions on the state variables and control actions. The simulation results of the developed procedure are presented.

The paper deals with the twin rotor MIMO system, which behavior is much similar to the behavior of a real technical device – a helicopter. The tracking problem of the generalized coordinates (yaw and pitch angles) for the given trajectories is posed in the conditions of the model's parametric uncertainties and in the action of unknown external disturbances. The decomposition synthesis of the control law is performed on the basis of the block approach using non-linear S-shaped sigmoidal feedbacks. The reduced order state observer with sigmoidal corrective action is constructed to obtain the estimates of the generalized velocities when generalized coordinates are measured. It is shown that the use of sigmoidal feedback allows us to reduce the possible overshoot at the beginning of transient responses, and to provide tracking of given signals with a given accuracy invariant with respect to parametric and external disturbances without using exogenous dynamic models of external influences.

For the orientation control system of the manipulator’s end effector with electrical actuators, we develop a decomposition pr ocedure of feedback law design to track given trajectories in the end effector’s coordinate system. Owing to the S-shaped smooth sigma-functions used as the local feedback laws and corrections of the state observer, the tracking system is invariant with a given accuracy with respect to existing uncertainties under constraints imposed on the variables of the mechanical subsystem. The suggested approach does not involve the solution of the inverse kinematics and dynamics problems and also relaxes the requirements to the volume of a priori information about the plant and external perturbations.

Renewed technology has created a demand for foods which are natural in taste, minimally processed, and safe for consumption. Although thermal processing, such as pasteurization and sterilization, effectively limits pathogenic bacteria, it alters the aroma, flavor, and structural properties of milk and milk products. Nonthermal technologies have been used as an alternative to traditional thermal processing technology and have the ability to provide safe and healthy dairy products without affecting their nutritional composition and organoleptic properties. Other than nonthermal technologies, infrared spectroscopy is a nondestructive technique and may also be used for predicting the shelf life and microbial loads in milk. This review explains the role of pascalization or nonthermal techniques such as high-pressure processing (HPP), pulsed electric field (PEF), ultrasound (US), ultraviolet (UV), cold plasma treatment, membrane filtration, micro fluidization, and infrared spectroscopy in milk processing and preservation.

The Escherichia coli Dps protein belongs to a specific family of bacterial ferritins; it is a nanosized particle that contains an inorganic core (~5 nm in diameter) and a protein shell with a size of 8–9 nm. The protein shell consists of 12 identical subunits with the known crystal structure of a dodecamer. The composition and structure of the core have been less studied. The core formation is associated with the oxidation products of Fe2+ ions in the ferroxidase centers of the protein. Thus, Fe2O3 oxides are the main compounds of the core. However, the mineralization properties of Fe2+ ions under anaerobic conditions in vitro may indicate a more complicated composition of the core in the native Dps protein. This paper presents a technique for the preparation of purified Dps samples for ultrahigh vacuum synchrotron experiments by X-ray absorption near edge structure spectroscopy of the iron absorption edge in the soft X-ray region. The conducted synchrotron experiments have revealed the presence of both trivalent and divalent iron ions in the octahedral and tetrahedral environment of oxygen atoms in the prepared biological samples. This points to a complex ionic composition of the core even in the native Dps protein, which has been isolated from aerobically grown bacteria.

The EN 1435 standards and State Standard GOST 7512 are compared and corrections to State Standard GOST 7512 are recommended.

In the Two Beam Accelerator (TBA), wakefield power extractors which extract high power RF from a high current beam are used to power high gradient accelerating structures. A dielectric‐based Wakefield Power Extractor (DWPE) is one option in addition to the metallic structures considered previously, like the CLIC PETS (Power Extraction and Transfer Structure). 7.8 GHz and 26 GHz DWPE prototypes have been successfully built and tested at the Argonne Wakefield Accelerator (AWA) facility. We are currently designing an X‐band version for a potential application with the CLIC beam. In this article, we report on test results of the 26 GHz DWPE and the preliminary design of the X‐band structure. Future plan and possible difficulties in the development of DWPEs are also discussed.

We report on a design of a TM‐mode based metamaterial‐loaded waveguide. Network analyzer measurements demonstrated a left‐handed propagation region for the TM11 mode at around 10 GHz. A beamline experiment was performed with the metamaterial‐loaded waveguide. In this experiment, a 6 MeV electron beam passes through the waveguide and generates a wakefield, via the Cherenkov radiation mechanism. We detected a signal in the left‐handed frequency band at 10 GHz. This is an indirect demonstration of reverse Cherenkov radiation as discussed in several papers. Cherenkov radiation in artificially constructed materials (metamaterials, MTM) can provide unusual, engineered features that can be advantageous for particle detector design.

RPCs are in use for many high energy physics applications where there is no need for fine spatial resolution. However, there are applications such as digital calorimetry where the dimension of the induced charge at pick-up pads is of interest. Such calorimetry is proposed for eg, Particle flow calorimetrey at the ILC. While there are both experiments and calculations which address this to some extent, we have been able to read out a single gap RPC using fine pitch laser etched two-dimensional strip readout as used in GEM tracking. This measurement was made in the Fermilab test beam in conjunction with the GEM tracking test for the STAR upgrade. We discuss both data and electrostatic simulations of the signal from a single gap glass RPC.

The design and efficiency of multilayer packets of downcomerless grid and tube-grid trays were evaluated against directed-jet and valve trays in the distillation of a model mixture of benzene and toluene in a 1000-mm diameter column. The trays were tested at infinite reflux. Column flooding was detected by a sharp increase in pressure and a decrease in temperature in the column bottom and by a decrease in separating capacity. Quality of feed, reflux, and distillate was monitored chromatographically. Column operating efficiency was evaluated on the basis of the height equivalent to a theoretical plate. The highest efficiencies and capacities were demonstrated by the directed-jet and downcomerless tube-grid trays. The latter trays can also be used for removal and supply of heat for distillation columns. Statistical and hydraulic data are cited for the investigation.