Preliminary Performance Assessment Research Articles

The attainment of gender education equality: A preliminary assessment of country performance in sub-Saharan Africa

The research literature on girls’ education in low and middle income countries focuses almost exclusively on ‘what works?’ which is confined mainly to relatively small scale experimental interventions, particularly randomised control trials This evidence is important but it provides few insights about the overall (especially more recent) progress made by individual countries and the overall effectiveness of the national strategies and specific policies in promoting girls’ education. This article is an initial attempt to redress this research imbalance. It has three principal objectives. Firstly, it outlines a broad conceptual framework which provides the basis for a holistic analysis of country-level performance in improving girls’ education. Secondly, it presents an initial, tentative assessment of country performance in improving girls’ education across sub-Saharan Africa. And thirdly, it explores some of the potentially key national characteristics and policy interventions which may help to explain the considerable variability in country performance during the last two decades in redressing gender inequalities in education in this region.

An Approach to the Preliminary Sizing and Performance Assessment of Spaceplanes’ Landing Parafoils

In this new era of space exploration, reusability and lower environmental impact are critical drivers in pursuing innovative solutions for access to space. One of these leading solutions is the Space Rider, a European reusable space plane with the ability to be both an “access to space” and a “return from space”. Following the lesson learned from the Intermediate eXperimental Vehicle (IXV) design and testing, the Space Rider will be equipped with a parafoil to enhance manoeuvrability during landing. Politecnico di Torino (PoliTO), in collaboration with Thales Alenia Space Italy (TAS-I), has developed an integrated tool to assess the landing performances of spaceplanes equipped with parafoils during conceptual design. The presented approach fuses sizing, dynamic models, guidance and control algorithms to provide a software suite for the rapid prototyping, sizing and performance assessment of spaceplanes’ parafoils. This paper details the implementation, mathematical background, validation and lessons learned behind the different software modules.

Preliminary assessment of the mooring fatigue performance of a semi-submersible platform in time-domain utilizing fracture mechanics-based approach

• Fully coupled dynamic analysis of platform-mooring system is performed in time-domain. • A self-integrated program is developed for mooring fatigue analysis through fracture mechanics-based approach. • Mooring fatigue performance of a submerged platform is studied through the remaining fatigue life at different positions of diverse lines. • The influence of corrosion on fatigue performance is investigated through a finite element model with gradual degradation. This paper aims to propose a universal time-domain fatigue evaluation method for mooring fatigue analysis of marine structures utilizing a fracture mechanics-based approach. First, the tension history of the mooring lines is calculated in the time-domain through hydrodynamic analysis and converted into mooring tension cycles with corresponding ranges via the rain-flow counting method. Subsequently, mooring fatigue performance is characterized through a self-integrated program which can realize the automatic crack propagation, Stress Intensify Factor (SIF) calculation and fatigue life prediction. Finally, a comparative study is implemented to further investigate the fatigue performance at different evaluation positions of various mooring lines under various corrosion rates. Results illustrate that fatigue life is relatively longer for mooring lines on the wave-ward side and greater at both ends of each line for the applied semi-taut mooring system. Most residual mooring fatigue life is more than 129 years with an initial surface crack of a = 0.5 mm, and the crack growth rate accelerates dramatically when reaching about 2.1% of the chain diameter. Remaining fatigue life decreases significantly under increasing corrosion rates, which is typically reduced by 39.4%, 48%, 47.8% and 38.6% for mooring lines 2, 5, 8, and 11 at 0.2 mm/year corrosion rate.

AOSRV: Development and preliminary performance assessment of a new robotic system for autonomous percutaneous vertebroplasty.

Percutaneous vertebroplasty (PVP) is one of the most effective treatments for patients with vertebral fracture that need surgical treatment, and surgical robotics are promising tools to provide surgeons with improved precision, surgical efficiency and reduce radiation exposure. However, there are currently few robotics that are developed to help assist with PVP. A new spinal surgical robotic system 'AOSRV' for autonomous vertebral puncture and bone cement injection was designed and customised in this study. To investigate its practical abilities and the advantages, we performed single-segment/double-segment PVP simulation surgeries on pig spinal specimens manually and using AOSRV. By contrast with the freehand group (FG) in single-segment (SS)/double-segment (DS) surgery, the robotic group (RG) was superior in the operation time (RGSS=21.14±4.11min, FGSS=33.17±6.83min; RGDS=42.39±7.31min, FGDS=62.86±20.39min), puncture adjustments (RGSS=2.30±1.77, FGSS=14.86±5.46; RGDS=3.91±1.76, FGDS=20.00±7.76), intraoperative fluoroscopies (RGSS=4.10±1.52, FGSS=20.57±5.44; RGDS=7.82±1.40, FGDS=25.91±7.23) and bone cement leakage rate (RGSS=30%, FGSS=71.4%; RGDS=38.6%, FGDS=83.3%). AOSRV was successfully developed and had a promising preliminary performance. An innovative attempt was made for the blank space of the autonomous vertebroplasty surgical robotics, and it may shed a light on more promising applications in the future.

Receiver Sand Mitigation Measures along railways: CWE-based conceptual design and preliminary performance assessment

Desert railways are constantly exposed to incoming wind-blown sand. The railway structure locally disturbs the incoming sand drift, induces its accumulation, and ultimately suffers its harmful effects. Receiver Sand Mitigation Measures (SMMs) aerodynamically interact with the track system, induce sand erosion around it, and allow sand transport far downwind it. The conceptual and preliminary design of an innovative Receiver SMM called Sand Blower is developed in this study. The design is grounded on the aerodynamic behaviour of the baseline humped sleeper track system. The flow control strategy is intended to avoid boundary layer separation, and to promote local flow acceleration by means of the Venturi effect. The performance assessment is carried out by Computational Wind Engineering approach. It allows to simulate the local wind flow, to obtain the shear stress field at the wall, and to derive from it sand sedimentation, windward erosion and backward erosion conditions. The results show that the Sand Blower greatly increases the track system performance by reducing sand sedimentation and increasing sand erosion under wide range of wind speeds and directions.

Descriptive and inferential study of hardness, fatigue life, and crack propagation on PLA 3D-printed parts

This research work deals with the development of a methodology for the preliminary assessment of hardness, fatigue, and crack propagation performance of plastic parts manufactured employing polylactic acid (PLA), deposited layer by layer using Fused Filament Fabrication (FFF) technology. A commercial polylactic acid filament was used to print different sample geometries to assess shore D hardness and its correlation with raster direction angles of 0°, 0°/90°, and 0°/45°/− 45°, relative to a reference point, and with three different heat treatment temperatures namely 60 °C, 100 °C, and 140 °C. Additionally, fatigue life and crack propagation were assessed as a function of raster direction angle. Finally, a statistical modeling methodology was employed to obtain both linear equations and response surface plots to correlate performance with layer orientation and heat treatments. The results showed that samples produced at 0°/90° and 0°/45°/− 45° raster direction angles and heat-treated at 100 °C showed the highest hardness performance. Also, the samples produced at 0°/45°/− 45° raster direction angle showed the lowest crack propagation rate until a 200 µm length was achieved, after that the crack rate increased abruptly, reaching 1500 µm at around 4500 fatigue cycles; the 0°/90° raster direction angle reached a crack length of approximately 800 µm at the same number of cycles. The fatigue results showed that samples printed at 0°/45°/− 45° raster direction angles showed a fatigue life of 18,505 cycles, which is above the fatigue life found in samples produced employing the 0° and 0°/90° raster direction angles. The statistical analysis derived from the obtained results shows that the raster direction angle is key to defining the bulk properties of the 3D-printed PLA parts. It was also demonstrated that the use of statistical modeling is a design alternative in contrast to the theory of laminates for composites, which is worth studying and developing for the manufacturing of mechanical parts by 3D printing.

Experience of Cloud Seeding to Extinguish Wildfires in Siberia and the Far East in 2017–2021: Preliminary Results and Performance Assessment Issues

Experience of Cloud Seeding to Extinguish Wildfires in Siberia and the Far East in 2017–2021: Preliminary Results and Performance Assessment Issues

Sensitivity study of risk to future generations associated with the Geological Disposal of Radioactive Waste in the Jebel-Al-Dhanna salt dome

The disposal of Higher Activity Wastes, particularly long lived Heat Generating High Level Waste (HG-HLW) such as Spent Nuclear Fuel (SNF) is one of the biggest challenges encountered by the peaceful civil nuclear energy industry. The United Arab Emirates (UAE) has emplaced laws and instituted a policy in which geological disposal is a potential choice for SNF disposal. Available geological data in the public domain provide initial indications of geological environments that might be suitable to host a Geological Disposal Facility (GDF) in the UAE. This paper aims to present an indicative preliminary Performance Assessment (PA) demonstrating radiological dose and risk estimations from hosting a GDF in the Jebel al Dhanna (JAD) location consisting of an Evaporite geological environment in the form of a Salt Dome (Diapir) that protrude above the surface. Modelling the dispersion of harmful radionuclides from the GDF hosted at the JAD location is achieved by utilising GoldSim's Contaminant Transport code, which has successfully provided an evaluation of radiological risks to current and future generations from the disposal of the UAE's forecasted SNF inventory. The developed GoldSim model highlights the migration of radionuclides from within disposed waste packages, past the engineered barrier system (EBS), through the surrounding geosphere or the Natural Barrier System (NBS), reaching a reference receptor. Due to the lack of detailed and site specific data, analyses presented in this paper are to be viewed as generic and are not to be utilised directly as a site selection tool. The analyses presented are expected to go through several revisions and development stages once sufficient site specific data is made available and will then be presented in, and be a part of a UAE site specific safety case report. The analyses presented in this paper are not meant to be used in site selection decision making or in the assessment of the suitability of the location to host a GDF for nuclear waste. The selection of a site for a GDF in the UAE is a matter for the UAE Government and depend upon a more detailed analysis of site-specific conditions.

Особый режим налогообложения российских ИТ-компаний: от выбора преференций до налогового маневра в отрасли

IT industry is noticeably distinguished by the tax support provided to it in the Russian economy. Nowadays software companies are treated as main contributors to national technological breakthrough being one of the main priorities of federal tax policy. Tax maneuver of 2021 significantly changed well-known tax rules, but some of novelties became a logical development of previously implemented measures. We systematize them by following our classification that introduces three main phases, all of which provided a qualitative update of the previous taxation framework, and for analysis consider particular reliefs as a unified, specific tax regime integrated in the general taxation system. The purpose of the article is to identify priorities and evaluate effectiveness of mechanisms designed to stimulate IT companies, including a preliminary assessment of valid perimeter and performance of the maneuver. Obtained results indicate that the tax regime initially given to software business had a bad design, an extremely narrow scope of beneficiaries and, due to this, a little effect on the IT industry; modernization of that design with the revision of basics was necessary at least in order to stop the decline of IT industry in the part of small companies. However, the main trend of recent tax policy demonstrates a strengthening of sustainable business with comparative fall of competitiveness of beginning entrepreneurs. In sum, the tax maneuver has a positive economic impact but covers, according to our estimates, less than 20% of IT companies.

Sparsity-Based Time Delay Estimation Through the Matched Filter Outputs

In this letter, we deal with the problem of high-resolution time delay estimation (TDE) in multipath environments exploiting the matched filter (MF) outputs data. To this end, we develop a systematic post-processing framework, consisting of two sparsity-based algorithms and a refining procedure aimed at reducing the computational load. The TDE problem is formulated as a sparse signal recovery problem and efficiently solved resorting to a majorization-minimization paradigm and a cyclic procedure. At the design stage, we assume a complex-valued Gaussian distribution model for the MF samples and incorporate a module-product prior that promotes the sparsity more significantly than the conventional complex Laplacian distribution. The preliminary performance assessment, conducted on simulated data, shows that, at least for the considered parameter values, the proposed delay estimators approach the Cramér-Rao bound for different signal-to-noise ratios and bandwidths.

User-centered development and performance assessment of a modular full-body exoskeleton (AXO-SUIT)

This paper presents the design and preliminary performance assessment of a full-body assistive exoskeleton (AXO-SUIT) for older adults. AXO-SUIT is a system that consists of separate lower-body and upper-body modular exoskeletons, which can be combined to form a full-body system to provide flexible physical assistance as needed. The full-body exoskeleton comprises 27 degrees of freedom (dof), of which 17 are passive and 10 active. It can assist people in walking, standing, carrying and handling tasks. A user-centered design approach was adopted throughout the development of the exoskeleton. This paper describes the design process of AXO-SUIT, involving a review of user needs, a kinematic and kinetic motion study, and innovative system design. Tests with the developed systems were conducted on selected end-user subjects, covering both performance evaluations at different levels and useability testing. End-user testing results show the effectiveness of the exoskeleton in providing flexible physical assistance.

ASTEMA: Design and preliminary performance assessment of a novel tele-microsurgery system

To overcome the challenges of reconstructive microsurgery, a teleoperated robot called ASTEMA was built to help surgeons performing microanastomoses. The surgeons’ needs are first analyzed then the design steps are summarized. This robot is composed of three orthogonal linear actuators and a spherical wrist with its remote center of motion at the instrument tip. Geometric model of the spherical wrist was calibrated through mathematical optimization in order to compensate for imperfections of machining and assembling. Two preliminary experiments were carried out to assess the ASTEMA performance. The first was performed with a simple circular position trajectory. The second was a complex angular trajectory. Results show a significant improvement of gesture precision with respect to manual trajectory execution. They also show that subjects instinctively compensate the errors from the non-ideal wrist, thanks to visual feedback from microscope.

The Reduced-Degree-of-Freedom Model for Seismic Analysis of Predominantly Plan-Symmetric Reinforced Concrete Wall–Frame Building

A reduced-degree-of-freedom (RDOF) model for seismic analysis of predominantly plan-symmetric reinforced concrete (RC) wall–frame buildings is introduced. The RDOF model of the wall–frame building consists of elastic beam–column elements with concentrated plasticity used for simulating cantilever walls and predominantly plan-symmetric RC frame buildings that are represented by the improved fish-bone (IFB) model. In this paper, the capability of the RDOF model is demonstrated for two frame buildings and two wall–frame buildings. The RDOF models were defined directly from the building information model. This is an advantage of RDOF models with respect to single-degree-of-freedom (SDOF) models, while the computational robustness of the RDOF models also makes them attractive for the seismic analysis of building stock. The imposed cyclic displacement analyses conducted for the investigated buildings proved that the condensation of the degrees of freedom for RDOF models was appropriate. Consequently, only minor differences were observed for maximum storey drift IDA curves, maximum storey acceleration IDA curves, and seismic fragility functions for different limit states. However, development is needed to make RDOF models appropriate for preliminary seismic performance assessment of plan-irregular buildings.

A model-based design methodology for flight control systems: Global 7500 pitch control case study

This article introduces an original model-based design methodology addressing a high-performance aircraft design challenge: conflicting performance requirements. The case study of the Global 7500 elevator actuation system also provides in-depth insight into the complex design process of today’s fly-by-wire flight control systems. The methodology presented here redefines the aircraft manufacturer’s involvement in the design process of the systems, implementing analysis and iteration capabilities early in system development. To this end, it introduces a novel modeling approach for analyzing loaded rate requirements by simulating closed-loop performance with a generic nonlinear second-order state filter, including the main performance limitations without requiring a preliminary design definition. In this way, it provides means to mature the system requirements and addresses requirement conflicts upfront. Then, a simulation-based preliminary sizing and performance assessment validates the candidate design concept. It also secures the preliminary design phase by implementing advanced design uncertainties and involving interfacing systems and disciplines early in the process. The redefined methodology identified directly that the problem’s root cause was a conflict between stability and control and flutter protection requirements. It also indicated that the first sizing driver is the response time required under a specific failure case. These findings lead to an optimal elevator actuator design compliant with matured performance requirements. Thus, the methodology resolved a design challenge blocking the Global 7500 aircraft development and prevented redesign occurrences later during the detailed design phase. In this way, it directly contributed to the successful development of the Global 7500 and its optimal operational performance. This methodology applies to future aircraft design challenges, and the technical insight provides valuable lessons learned for high-performance T-tail business jets.

Design and Preliminary Performance Assessment of a Wearable Tremor Suppression Glove.

Approximately 25% of individualsliving with parkinsonian tremor do not respond to traditional treatments. Wearable tremor suppression devices (WTSD) provide an alternative approach, however, tremor in the fingers has not been given as much attention as tremor in the elbow and the wrist. Therefore, the objective of this study is to design a wearable tremor suppression glove that can suppress tremor simultaneously, but independently, in multiple hand joints without restricting the user's voluntary motion. A WTSD was designed for managing tremor in the index finger metacarpophalangeal (MCP) joint, thumb MCP joint, and the wrist. The prototype was tested and assessed on a participant living with parkinsonian tremor. The experimental evaluation showed an overall suppression of 73.1%, 80.7%, and 85.5% in resting tremor, 70.2%, 79.5%, and 81% in postural tremor, and 60.0%, 58.7%, and 65.0% in kinetic tremor in the index finger MCP joint, the thumb MCP joint, and the wrist, respectively. This first assessment of a WTSD for people living with Parkinson's disease provides confirmation of the feasibility of the approach. The next step requires a comprehensive validation on a broader population in order to evaluate the performance of the WTSD. This study demonstrates the feasibility of using a WTSD to manage hand and finger tremor. The device enriches the field of upper-limb tremor management, as the first WTSD for multiple joints of the hand.

Design of a Tandem Compressor for the Electrically-Driven Turbocharger of a Hybrid City Car

Within a broader national project aimed at the hybridization of a standard city car (the 998 cc Mitsubishi-derived gasoline engine of the Smart W451), our team tackled the problem of improving the supercharger performance and response. The originally conceived design innovation was that of eliminating the mechanical connection between the compressor and the turbine. In the course of the study, it turned out that it is also possible to modify both components to extract extra power from the engine and to use it to recharge the battery pack. This required a redesign of both compressor and turbine. First, the initial configuration was analyzed on the basis of the design data provided by the manufacturer. Then, a preliminary performance assessment of the turbocharged engine allowed us to identify three “typical” operating points that could be used to properly redesign the turbomachinery. It was decided to maintain the radial configuration for both turbine and compressor, but to redesign the latter by adding an inducer. For the turbine, only minor modifications to the nozzle guide vanes (NGV) and rotor blades shape were deemed necessary, while a more substantial modification was in order for the compressor. Fully 3-D computational fluid dynamics simulations of the rotating machines were performed to assess their performance at three operating points: the kick-in point of the original turbo (2000 rpm), the maximum power regime (5500 rpm), and an intermediate point (3500 rpm) close to the minimum specific fuel consumption for the original engine. The results presented in this paper demonstrate that the efficiency of the compressor is noticeably improved for steady operation at all three operating points, and that its choking characteristics have been improved, while its surge line has not been appreciably affected. The net energy recovery was also calculated and demonstrated interesting returns in terms of storable energy in the battery pack.

Preliminary assessment of environmental performance of ice formwork production method for irregular architectural elements of concrete

The present article communicates knowledge in sustainability of a method of digital fabrication in precast concrete production. The method, known as Ice Formwork, serves in production of ultrathin lightweight architectural elements – a novel design typology that has emerged with the development of High-Performance Fibre-Reinforced Concrete (HPFRC), and helps to reduce cement consumption, adopt digital fabrication processes, and increase design flexibility. In practice, however, this production employs suboptimal methods of mould-making, using petrochemical or engineered wood products for single-use moulds, entailing excessive amounts of non-recyclable waste. The current work builds on the research and development of a novel production method Ice Formwork facilitated through single-use moulds made of artificially frozen water. Previously published work on the subject has covered topics such as cement hydration at subfreezing temperature, subtractive digital processing of ice and a case of practical application illustrated with the production of a prototype of a lightweight façade rain screen. Yet, since artificial refrigeration and processing of large amounts of water is essential for Ice Formwork production, the environmental performance of this method requires a thorough examination. Thus, the current piece of work attempts to address two major issues, namely: (1) Energy consumption of industrial refrigeration in production of Ice Formwork. (2) Changes in water mineral content after a cycle of Ice Formwork concrete production. For both topics, the research work required development of an original experimental methodology. This aspect has been given the great attention and required development of new technical solutions on many levels. Further research and development is needed to come to a comprehensive environmental assessment, and the results of the current study merely provide a preparatory overview that can help to orient and properly set the objectives for the following research stages.

Tensile Performance of SHCC Road-Bridge Link Slabs in Fully Jointless Bridges

Deformation of the main girder is absorbed by a continuously reinforced concrete pavement (CRCP) with microcracks in fully jointless bridges. The conventional fully jointless bridge has been challenged by durability and reliability issues because the CRCP is vulnerable to crack and hard to control the crack width when it suffers temperature variation. In this paper, a new type of fully jointless bridge with the road-bridge link slabs using strain-hardening cementitious composite (SHCC) material is investigated. First, an experiment was carried out to study the material properties of SHCC material for a preliminary assessment of road-bridge link slab performance using this material. Results found that SHCC is adequate for link slabs for its high tensile ductility and fine cracks development. Second, an SHCC slab model tensile test was carried out to study the absorptive capacity and the crack distribution of the SHCC slab. Results verified the high absorptive deformation capacity of the SHCC slabs. When the longitudinal deformation reaches 10 mm, the surface cracks in the SHCC slab are fine and dense, the crack width is kept in 80 μm, and the internal force is small. Third, by comparing the tensile test results with a conventional CRCP slab with same length, it is found that an SHCC slab has higher absorption capacity, better crack distribution, and smaller internal force than a CRCP slab. Finally, through ABAQUS finite element modelling, the stress performance of SHCC road-bridge link slabs is simulated using a trilinear constitutive model. The calculated results are consistent with the experimental results.

IEEE 802.15.22.3 Spectrum Characterization and Occupancy Sensing Application Testbed

Dynamic Spectrum Access (DSA) is becoming a key enabler for wireless communication technologies. Many DSA concepts—such as the Citizens Broadband Radio Service and TV White Space—rely on spectrum databases to identify available radio channels. However, propagation models and other assumptions used by these databases are usually poor for the given scenario, typically leading to over-conservative calculations in terms of permitted secondary spectrum access, geographical bounds or transmit powers in order to mitigate perceived interference risk. Spectrum sensing allows better understanding of the actual propagation and actual channel impulse response, allowing spectrum databases to tune their propagation models to increase the availability of spectrum for secondary access as assessed by such spectrum databases, or to increase the availability of local access licenses as assessed by the telecommunications regulator. A critical limitation on the uptake of ubiquitous sensing is that measurement systems are either proprietary or do not have commercial use-cases; hence little economy of scale exists to drive deployment. For this reason, the IEEE 802.15.22.3 Task Group was formed to standardize a Spectrum Characterization and Occupancy Sensing (SCOS) system capable of addressing a wide range of sensing tasks and be easily and flexibly deployed across a variety of hardware options. This paper provides a high-level description of this system and a first testbed implementing the standard in a laboratory-controlled environment. Preliminary performance assessments are also reported, where it is shown that the system is able to detect users with a power level down to −80 dBm with a probability of detection equal to 1 and controlled false alarm rates.

Development of a Process-Oriented Tribological Test Rig for the Performance Assessment of Tool Coatings in Turning of Titanium Ti6Al4V

The interaction of cutting tool and workpiece in the contact zone is crucial with regard to tool wear. This is of particular relevance for difficult to machine materials such as titanium Ti6Al4V in continuous operations like turning. Due to the low thermal conductivity of titanium, the heat generated during cutting mainly flows into the tool leading to high tool temperatures. In addition, the low Young’s modulus in combination with the high yield strength of Ti6Al4V leads to high normal and shear stresses acting on the tool surfaces and to detrimental ploughing unless sharp cutting edges are used. Previous attempts to increase the tool life in turning of Ti6Al4V by coatings have not been satisfactory. Temperature active coatings are expected to reduce friction and thus tool wear, allowing for more productive cutting conditions or reduced use of coolant. Tribological conditions strongly differ between rake and clearance face in terms of sliding velocity, stress state and temperature, while insights into the contact zone during cutting are difficult to obtain. Thus, for preliminary assessment of the tool performance, tribological pin-on-disc tests are generally used. However, they suffer from the drawback of a closed friction system, as the pin repeatedly engages the same track on the material specimen, thereby affecting its tribological behavior. In order to suitably emulate mechanical and thermal conditions in continuous cutting, an open friction system has been designed, which is characterized by simultaneous adjustment and measurement of acting forces. At the same time, tool surface temperatures are captured by intermittent radiation measurement. Consequently, the open friction test rig enables the separate investigation of the tribological conditions of rake and clearance face. In this paper, the test rig design and first experimental results obtained from tribological investigations are reported. Separation of forces and subsequent evaluation of stresses acting on both tool surfaces is explained.