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Purpose: This study was designed to assess the safety and efficacy of 0.2 percent glyceryl trinitrate suppository form in the healing of chronic anal fissure. Methods: Thirty-four patients with symptomatic chronic anal fissures were assigned to 0.2 percent glyceryl trinitrate suppository (n = 21) or placebo (n = 13) in a double blind design. Patient's symptom scores were registered at first visit. A validated daily chart was given to assess their symptoms on a daily basis. Both groups received psyllium from the beginning of the study. They were assessed at two-week intervals for six weeks. Then, they started a washout period of one month and after that were crossed over for another six weeks. Chi-squared, t-tests, and analysis of variance were used for statistical analysis. Results: Complete healing at six weeks was achieved in 12 of 21 patients (57 percent) in the glyceryl trinitrate group and 5 of 13 patients (38 percent) in the placebo (P < 0.05).The overall healing rates at the end of study were 15 of 21 (71 percent) vs. 11 of 13 (84 percent) in the glyceryl trinitrate and placebo groups, respectively (P > 0.05). Conclusions: Application of 0.2 percent glyceryl trinitrate suppository form represents a new, promising, and effective treatment for chronic anal fissure.

Introduction:Angiography and angioplasty expose cardiologists to a high level of X-ray comparing other radiographic methods, due to the high dose of radiation and the presence of the physician beside the patient bed during the procedure. Therefore, this study was designed to measure the absorbed dose in some important organs and extremities in cardiologists during different angiography and angioplasty procedures in catheterization lab. Methods:The entrance skin dose and extremity absorbed dose of the physicians in 100 angiography and angioplasty procedures were measured by TLD chips. The points on the physicians’ body, which were measured in this study, included: thyroid, right and left chest, right and left wrists, and left leg. The correlation of entrance skin dose in these six points to the exposure parameters is also evaluated. Results:The left leg has maximum dose and maximum correlation with total DAP for all three physicians in all procedure types. There was a weak correlation between left wrist absorbed dose and number of views among three physicians. Also, the maximum annual absorbed dose of the physicians in the left leg was lower than 150 mSv. Conclusion:According to the results of this study, it can be stated that periodic leg and hand dosimetry during operation is necessary for interventional cardiologists. Results also showed that, regardless of the type of procedure, the characteristics of device output, especially DAP, have a direct role in the absorbed dose of the organs and extremities, especially those outside the shield.

This paper presents the mission concept and engineering design of a debris-removing nanosatellite called Deorbiter CubeSat, within the framework of NASA’s Pre-Phase A studies. The spacecraft is designed based on the utilization of an eight-unit form factor, and is intended for the removal of predetermined sizable debris objects from the low Earth orbit. A number of attitude and orbit determination sensors and control actuators are included on the CubeSat, which are employed during the rendezvous, attachment, and deorbiting operations. Upon attaching to a debris, the CubeSat stabilizes the rotational motion of the debris, and then proceeds to reducing the debris orbit size, in order to re-enter Earth’s atmosphere and burn up due to the high atmospheric density. The engineering design of Deorbiter CubeSat is outlined, and the selected components are detailed. The selected components are commercially available and have long space heritage. System’s mass budget is analyzed, and preliminary component costs are estimated. Three scenarios for the Deorbiter CubeSat mission operations are considered, and the spacecraft power budget and components duty cycles are investigated for each scenario. In light of the results, the feasibility of each scenario for the Deorbiter CubeSat mission is discussed.

This article discusses a convex-optimization-based planning method for a geostationary satellite to determine station keeping and momentum unloading maneuvers concurrently. The proposed optimization algorithm incorporates a dual-rate prediction model to address the time scaling difference between the coupled slow orbital and fast attitude dynamics. The use of combined prediction model in the optimization problem facilitates to include state constraints accounting for the desired orbital and momentum unloading requirements. Maneuver plans are determined by solving a convex optimization problem in a receding horizon control form. The main objective of the proposed algorithm is to minimize fuel consumption while managing the stored momentum, in order to maintain a satellite in a tight station keeping window and nadir pointing attitude configuration. Numerical simulations are performed to validate the proposed optimization algorithm in terms of fuel consumption and constraint enforcement.

The control of a spacecraft equipped with a six-degree-of-freedom robot manipulator is studied in this paper. The objective is to rendezvous and synchronize with a satellite to facilitate inspection, servicing or de-orbiting. The space manipulator dynamics model with global parameterization on the configuration manifold is derived and used for designing asymptotically-stable control laws, so that they are valid globally in the configuration manifold. The control system consists of a sliding-mode rendezvous controller as well as a geometric attitude synchronization and a model-based servo control for the robot manipulator. The gains of the sliding-mode controller dictate a user-defined upper-bound on the thrust force. The attitude synchronization controller, concurrently with the rendezvous controller, is capable of micro-orbiting the space manipulator around spinning or tumbling satellites. It is observed through the simulations that the controller consumes limited amount of propellant, and it is feasible to use it for either a re-fueling (larger mass) or a de-orbiting (smaller mass) space manipulator.

Minimum quantity lubrication (MQL) technique is an efficient and eco-friendly method of lubricant application in machining processes. The lubricant type applied in this technique is not only important in relation to environmental aspects but also has a great effect on machining efficiency. Nanolubricant (nanofluid) is composed of nanoparticles suspended in base oil and shows prominent lubrication performance. In the present study, the effects of minimum quantity nano-lubrication (MQNL) in surface grinding of Tungsten carbide grade YG8 is experimentally investigated. The nanolubricants applied in the experiments include MoS2, graphite, and Al2O3nanoparticles (with varying concentration) dispersed in two different base oils- mineral oil (paraffin) and vegetable oil (sunflower). The grinding outputs such as specific energy, cutting force, and surface quality were used as measurands for determining the process efficiency. Furthermore, performance evaluation of MQNL in grinding process of WC material was performed by comparing the grinding outputs at different environment such as dry, wet, and MQL. The results show that, if nanoparticles are selected properly, MQNL technique is an effective method to improve the process efficiency by reducing the grinding force, specific energy, and increasing surface quality.

A t-regular self-complementary k-hypergraph, denoted by $$\hbox {SRHG}(t,k,v)$$ SRHG(t,k,v) , is a k-hypergraph with a v-set Vas vertex set and an edge set E, such that every t-subset of Vlies in the same number of edges and there is a permutation $$\sigma \in S_v $$ σ∈Sv with the property that $$e\in E$$ e∈E if and only if $$\sigma (e)\notin E$$ σ(e)∉E . It is clear that a set of trivial necessary conditions for the existence of an $$\hbox {SRHG}(t,k,v)$$ SRHG(t,k,v) is that $${v-i\atopwithdelims ()k-i}$$ v-ik-i is an even integer for all $$i=0,1,...,t$$ i=0,1,...,t . In this paper, we extend the method of partitionable sets for constructing large sets of t-designs to obtain new $$\hbox {SRHG}(t,k,v)$$ SRHG(t,k,v) . In particular, we present $$\hbox {SRHG}(2,3,10)$$ SRHG(2,3,10) , $$\hbox {SRHG}(2,4,10)$$ SRHG(2,4,10) , $$\hbox {SRHG}(2,4,11)$$ SRHG(2,4,11) and $$\hbox {SRHG}(2,5,10)$$ SRHG(2,5,10) . Also we show that the trivial necessary conditions for the existence of $$\hbox {SRHG}(2,k,v)$$ SRHG(2,k,v) with $$k\le 7$$ k≤7 are sufficient.

In this paper, a low-thrust tugboat redirection method is assessed using multiple spacecraft for a target range of small near-Earth asteroids. The benefits of a landed configuration of tugboat spacecraft in formation are examined for the redirection of a near-Earth asteroid. The tugboat method uses a gimballed thruster with a highly collimated ion beam to generate a thrust on the asteroid. The target asteroid range focuses on near-Earth asteroids smaller than 150 m in diameter, and carbonaceous (C-type) asteroids, due to the volatiles available for in-situ utilization. The assessment focuses primarily on the three key parameters, i.e., the asteroid mass redirected, the timeframe for redirection, and the overall system cost. An evaluation methodology for each parameter is discussed in detail, and the parameters are employed to determine the expected return and feasibility of the redirection mission. The number of spacecraft employed is optimized along with the electrical power needed for each spacecraft to ensure the highest possible return on investment. A discussion of the optimization results and the benefits of spacecraft formation for the tugboat method are presented.

This paper discusses design and implementation of a quaternion-based attitude control system for the short-duration mission of suborbital modules using cold-gas thrusters. The quaternion-based controller generates a command torque for each channel, and a pulse-width pulse-frequency (PWPF) modulator determines the required fire signals for the thrusters. The system performance is examined through both numerical and hardware-in-the-loop simulations.

► MQL is an efficient and ecologically friendly method of fluid application. ► Efficient lubrication is related to spray atomization and machining conditions. ► MQL spray parameters are investigated theoretically and experimentally. ► By applying optimal spray delivery parameters efficient lubrication takes place. ► MQL can decrease the challenges existing in ceramics grinding process.

Tappeh-Zaghe is an important archaeological site, located in the northern part of the Persian plateau, and dated to prehistoric times (~5100 BC). The pottery from Tappeh-Zaghe shows an astonishingly fine manufacture. Multianalytical methods have been applied to determine the general chemical composition and the manufacturing process of the ceramic of this period. The results of this investigation show that the pottery from Tappeh-Zaghe was locally produced. The samples are characterised by three distinguishable layers, consisting of clay materials in the core and fine processed quartz aggregates mixed with lime paste on the surface. The external layer is decorated with a painted reddish decoration. The well processed quartz aggregates indicate that the potters applied the external layer on the surface to obtain a structure providing better conditions for decorating and painting, and also more resistant against thermal shock.

Ancient bronze objects buried in the soil for a long time corrode because of various environmental conditions. This can also cause different corrosion morphologies. One of the features of ancient bronzes is the presence of unalloyed copper with copper inclusions (UCI); when in the alloying process, the copper–tin alloy did not form properly. Because of the phenomenon of preferential corrosion, the tin content decreases in an environment with low oxygen and high chloride and sulphide content. The results are various corrosion products. A decorative plaque belonging to the National Museum of Iran has been investigated by X-ray diffraction, SEM-EDX and reflected polarised light optical microscopy. The investigations showed that the UCI effect appeared as type B, i.e. with copper sulphide in the metallic core. The presence of UCI (type B) in ancient bronzes proves that the objects corroded after deposition in the soil.

Nimonic 115 is one of the essential Nickel-based super alloys is known as one of the most difficult-to-cut materials because of its unique properties. Appropriate selection of the machining parameters in milling of this material is so vital for improving the machining efficiency. This paper discusses the use of response surface methodology for modeling of surface roughness in milling of Nimonic 115 with coated carbide tools. The machining parameters used in this study, are cutting speed, feed rate, axial and radial depth of cut. Average Surface roughness was measured in different conditions and analysis of variance (ANOVA)was performed. Then, quadratic model for predicting the surface roughness is established. The results show that the most significant parameter which affects surface roughness is feed rate.

Abstract: This paper addresses optimization of a high-speed digital feedback controller for a plasma position in Damavand tokamak. Damavand tokamak discharges have plasma currents up to 40 kA with discharge duration greater than 15 ms and toroidal magnetic fields up to 1.2 T. The plasma position is measured using saddle-loops and Rogowski coil and is controlled by electromagnetic forces generated by passing currents through control coils placed around the plasma. A desired control objective is maintaining the plasma in the center of vacuum vessel and to stabilize the plasma in the presence of disturbances in a time domain of the order of few milliseconds. In order to achieve maximum performance it is essential to optimize the control system. In this paper plasma position measurement and the details of implementing high-speed PID controllers based on a TMS320c25 digital signal processor along with the system optimization are presented.

Abstract: Some domean volcanoes built by acidic to intermediate lavas are described. They were intruded, probably in Pliocene, into the neogenic volcano-sedimentary formations of the volcanic Tabriz — Bazman Zone (Central Iran). Some of them are intrusive domes which certainly did not reach the existing topographical surface when emplaced; others are extrusive domes which exhibit some interesting featuresviz.: hypogenous emplacement of the Suleghan dome, typical ring shape of the Dastjerd dome, etc. A provisional classification of domean volcanism in proposed in conclusion.

The possible presence of Hendersonula toruloideain the environment and its role as a human pathogen in Iran was studied. Samples were collected both from trees likely to be infected and from patients who presented with suspected fungal infections of the hands and feet. The samples were mainly collected in areas of southern Iran where the climate is similar to that of areas where H. toruloideahas been found previously to infect humans. H. toruloideatype B was isolated from plant samples (eucalyptus trees) for the first time in Iran but it could not be isolated as a human pathogen.

Several alkyl and polyhalophenyl esters of benzo[b]‐3‐methyl‐2‐furancarbamic acid were prepared and tested for anti‐fungal activity against Candida albicans, Penicillium notatum, and Aspergillus niger. The pentachlorophenyl ester was the most active substance and the only compound to show antibacterial activity against Staphylococcus aureus.

This paper presents a geometrical approach to the dynamical reduction of a class of constrained mechanical systems. The mechanical systems considered are with affine nonholonomic constraints plus a symmetry group. The dynamical equations are formulated in a Hamiltonian formalism using the Hamilton–d'Alembert equation, and constraint forces determine an affine distribution on the configuration manifold. The proposed reduction approach consists of three main steps: (1) restricting to the constrained submanifold of the phase space, (2) quotienting the constrained submanifold, and (3) identifying the quotient manifold with a cotangent bundle. Finally, as a case study, the dynamical reduction of a two-wheeled rover on a rotating disk is detailed. The symmetry group for this example is the relative configuration manifold of the rover with respect to the inertial space. The proposed approach in this paper unifies the existing reduction procedures for symmetric Hamiltonian systems with conserved momentum, and for Chaplygin systems, which are normally treated separately in the literature. Another characteristic of this approach is that although it tracks the structure of the equations in each reduction step, it does not insist on preserving the properties of the system. For example, the resulting dynamical equations may no longer correspond to a Hamiltonian system. As a result, the invariance condition of the Hamiltonian under a group action that lies at the heart of almost every reduction procedure is relaxed.

This paper discusses the design and development of a new Modular, Autonomously Reconfigurable Serial manipulator platform for advanced manufacturing, termed as the MARS manipulator. The platform consists of i) an 18-Degree-of-Freedom (DOF) serial-link manipulator capable of locking any of its joints at any position in their continuous range, such that it can emulate fewer-DOF serial manipulators with different kinematic and dynamic parameters, and ii) an integrated simulation and design environment that provides control over the manipulator hardware as well as a toolset for the design, implementation and optimization of a desired manipulator configuration for a given task. The effectiveness of the MARS manipulator to adapt its configuration to various tasks is examined by assuming two well-known configurations, SCARA and articulated, and by performing a specific task with each of them. The variation in effectiveness of the two configurations in terms of the end-effector trajectory, end-effector accuracy and power consumption is discussed. Further, these configurations are optimized with respect to their performance accuracy, and compared to their pre-optimized versions. Finally, the accuracy model of the simulation is compared against the physical hardware system, running the same task.

Several polyhalophenyl esters of p-sulfamoylcarbanilic acid were prepared and tested for antifungal activity against Candida albicans, Penicillium notatum, and Aspergillus niger.Pentachloro-, tribromo-, and triiodophenyl esters were found to be the most active.