Miracle-dz/UniFAR-FTUs huggingface dataset:
Experimental and Analytical Study of Hydrogen Jet Fire in a Vented Enclosure

An experimental and numerical study of hydrogen jet fire in a confined space was performed forhydrogen safety purposes within the European HyIndoor project (www.hyindoor.eu). An existence of two combustion regimes was numerically found and then experimentally confirmed. Depending on hydrogen mass flow rate, volume of the enclosure and vent area a well-ventilated or under-ventilated jet fire may occur. A chamber of 1x1x1 m3 with upper and lower vent positions, vent areas from 1 to 90 cm2 and different hydrogen mass flow rates from 0.027 to 1.087 g/s were used for numerical simulations and experimental validation. A lower axial position of a jet fire produced by immediate ignition of a hydrogen leak was established in the tests. A Background Oriented Schlieren (BOS) technique combined with high speed camera, pressure and temperature measurements were utilized in the tests to evaluate dynamics of the combustion process. In case of small hydrogen release rate and large vent area, a relatively stable well-ventilated regime leading to over-pressure not more than 0.8 mbar and a maximum internal temperature of 540 C was established. In case of very high hydrogen mass flow rate and relatively small vent sizes three different scenario of under-ventilated jet fire behaviour with self-extinction, re-ignition and external flame modes leading to very high overpressure of 10-100 mbar and maximum temperatures of 1000-1200 C were experimentally measured. Strong influence of steam condensation on under-ventilated jet fire behaviour results in reduced sub-atmospheric pressures inside the chamber and intensive air ingress into the chamber. It may result in re-ignition of the quenched flame and then again to the extinction.
CORPORATE LEADERSHIP AND PERFORMANCE OF MACHAKOS WATER AND SEWERAGE COMPANY IN KENYA

This study sought to investigate the effect of board leadership on performance of Machakos Water and Sewerage Company in Kenya. It had been noted that the performance of this company had been fluctuating making it difficult to deliver services to the stakeholders and operate at the required minimum service levels. The research variables were underpinned on the postulates of stewardship theory. Descriptive research design was adopted and utilized as a strategy for integrating the different components of the study in a coherent and logical way. The unit of analysis was Machakos Water and Sewerage Company. However, the unit of observation comprised of employees from the functional areas of the company. A representative sample was selected from the target population using proportionate stratified random sampling technique. The study used both primary and secondary data. Primary data was collected using structured questionnaire whereas secondary data was obtained through a review of relevant published reports in order to validate the data collected from the field. The research instrument was administered through the drop and pick method with an object of enhancing the response rate. The response rate for this study was eighty eight percent which was considered sufficient for making inferences and drawing conclusions. The quantitative data was analysed using mean, standard deviation and regression analysis. Results of analysis were presented using figures and tables. The findings of study revealed that corporate leadership has a positive contribution to the overall performance of the company. Drawing from these inferences, management of Machakos Water and Sewerage Company should formulate favourable policies on corporate leadership and support inherent practices through availing commensurate resources so as to improve corporate performance. It’s further recommended that management should leverage on CEO duality, leadership styles and motivation to enhance the operational efficiency of the company. Key Words : Corporate Governance, Corporate Leadership and Performance
Prediction of Turkey's Denim Trousers Export Using Artificial Neural Networks and the Autoregressive Integrated Moving Average Model

In this study, Turkey’s denim trouser export was predicted using ANN and ARIMA models. ANN models were composed from the import of denim trousers, the minimum wage, the price of cotton, electricity, and water, the value of TRY against USD, the credit usage of ready-made clothing enterprises, export credits, the real effective exchange rate, brands of denim trousers, and the denim trouser Balasa Index. It is observed that the best prediction is provided by MLP, the second - with ERNN and the third - with ARIMA. The reason why the export of denim trousers is not completely modeled can be explained by the economic downturn, which began in 2008 and still continues. However, it is clearly seen that ANN models predict more successfully than ARIMA ones.
Flight call rates of migrating thrushes: effects of wind conditions, humidity and time of day at an illuminated offshore platform

Many bird species call during migration, but call rates not necessarily reflect migration intensity. They rather seem to increase under deteriorating flight conditions. Often, nocturnal mass collisions at illuminated structures coincide with such conditions and are accompanied with high call rates of migrants. Thus, call rates could act as an indicator for situations with high collision risk for birds namely at offshore sites with hardly any alternatives for landing. In the face of increasing numbers of offshore wind farms knowledge about the environmental conditions in which maximum call rates occur, is needed for mitigation measures. In this first long-term study at an offshore site in the southern North Sea we investigated the effect of weather on the frequency of flight calls of three thrush-species at an illuminated platform. Flight calls were registered automatically during three autumn migration seasons. Besides generally higher call rates from 5 to 2 h before until 6 h after midnight, call rates increased with tailwinds, a change of the tailwind component during the first part of the night, offshore crosswinds and very high humidity. A monitoring programme is suggested that could help to reduce mass mortalities at illuminated structures.
Quantifying the Second-Round Effects of Supply-Side Shocks on Inflation

This paper uses a small-scale dynamic rational expectations model based on an open-economy version of Fuhrer-Moore-type staggered wage setting to quantify the second-round effects of selected supply-side shocks and of shocks to the nominal exchange rate on wages and subsequently on inflation. In order to analyse the desired reaction of the central bank to these shocks, optimal time-consistent policy rules are derived within the presented New-Keynesian framework. The conclusions presented in the paper suggest that the second-round effects of shocks to import prices and the nominal exchange rate on inflation should not be ignored in practical policy-making.
Methods for Blind Estimation of the Variance of Mixed Noise and Their Performance Analysis

Modern imaging systems provide a huge amount of images nowadays. These images are of different original quality. Some of them are practically ready for exploitation, e.g., visual inspection, object recognition, etc. Other ones need to be pre-processed as, e.g., by filtering, edge detection, segmentation, compression (Pratt, 2007; Bovik, 2000; Al-ShaykhM Elad, 2010). Such information is exploited by modern methods and algorithms of image denoising (Elad, 2010; SendurS Donoho, 1995; Mallat, 1998), edge detection (Pratt, 2007; Touzi, 2002) for setting proper thresholds that depend on noise statistics. In some practical situations, noise type and basic characteristics are known in advance. An example is radar imaging by synthetic aperture radar (SAR) with known number of looks and image forming mode (OliverQ Foi et al., 2007), etc. Then, noise characteristics are to be estimated for each particular image subject to further processing, for example, filtering or compression (Liu et al., 2008; Foi et al., 2007; Lukin et al., 2011). Similar situation holds for hyperspectral imaging where noise properties and signal-to-noise ratio (SNR) depend upon sub-band and they vary considerably in different component (subband) images (CurranD Uss et al., 2011). Note that below we mainly focus on considering multichannel images where the general term “multichannel” relates to color, multiand hyperspectral imaging, dual and multipolarization radar imaging, multitemporal sensing, where multiple images of the same scene or terrain are obtained. While for one or a few images it is sometimes possible to carry out manual (interactive) image analysis for the determination of noise type and characteristics, it becomes impossible or too labour-consuming to perform such actions for multichannel data, especially if estimation is to be done on-board or under conditions of fast
Biometrics of Citril Finch Serinus citrinella in the west Pyrenees and the influence of feather abrasion on biometric data

Biometric data are an essential component of studies into the breeding biology of bird populations. Citril Finches Serinus citrinella in the Pyrenees mainly feed on pine seeds, and coniferous habitats in the west Pyrenees are of significant conservation importance. The aim of this study was to increase our understanding of morphological variation in Citril Finches breeding in the west Pyrenees, north Iberia, within a region of grasslands and woodlands of Scots pine Pinus sylvestris. Individuals (1,118) were mist netted, ringed and measured. Wing and tail length were influenced by feather abrasion, particularly in juvenile birds. Overall, male Citril Finches were larger than females for all structural and flight‐feather measurements (wing, tail, tarsus and culmen length, bill depth and width and lower mandible length), and adults were larger than young birds (except for tail length, culmen length and bill depth). There was significant year‐to‐year variation for all measurements apart from tail length, but the reasons for this are unknown. Principal Components Analyses (PCA) were used to analyse wing and bill morphology. Adult birds had narrower, more pointed wings than young birds, and the wing shape in males was more pointed than in females. There were only sex‐specific differences in bill morphology, with males having more robust bills. We obtained a discriminant function to classify the sex of birds before their post‐juvenile moult.
Structural waves in nondestructive testing

This thesis investigates theoretically and experimentally the application of struc¬ tural waves m nondestructive testing and evaluation The characteristic length of a "structural wave" is large compared to the thickness of the structure in which it propagates If such a wave hits a defect in a mechanical component, waves which propagate in the structure are generated together with local oscillations m the vicinity of the defect The amplitude and the phase of the scattered wave at various frequencies and the arrival time at various locations in the structure contam mformation on the position, size and kind of the defect The number of measurements necessary for the nondestructive testang depends on the geometry of the structure In a "one-dimensional" component such as a beam, rod or a wire, the whole structure can be tested in one single experiment In "twodimensional" components such as plates or shells, several measurements are needed However, a scanning as it is performed in classical ultrasonic testing is not necessary The application of structural waves is therefore very suitable for the fast inspection of large components After an introductory chapter, the behaviour of a structural wave pulse in a cracked rod is investigated m chapter 2 A mathematical model, based on linear-elastic fracture mechanics, is presented It allows the prediction of the reflection and trans¬ mission characteristics of a wave pulse at a defect The theoretical results are com¬ pared to experiments which were performed at cylindrical rods with a lateral crack Chapter 3 describes an effect which has been observed in the context of the experi¬ mental investigations m chapter 2 The direction of the deflection vector of a flexural wave pulse seems to be rotated as the pulse propagates in the rod This effect could be explamed by a small deviation in the rod's properties in the two principal directions of the cross-section This is in analogy to the half-wave plates which are used m laser optics in order to change the direction of polarisation of light The dif¬ ference in the two flexural stiffnesses of the rod is less than 1% It seems to be generated by a variation of the tensile modulus in the longitudinal direction (E^) across the diameter of the rod The experiments to this thesis are described in chapter 4 Transient wave pulses with well-defined frequency spectrum were generated with the help of piezoelectric transducers These are driven far below their first eigenfrequency, usually in the range from 1 to 200 kHz The resulting motion of the structure is measured by means of a heterodyne laser interferometer with phase demodulation It allows the measurement of displacements smaller than 1 nm even at low frequencies (<10kHz) This is not possible if an interferometer with fringe counter or frequency demodulator is used The piezoelectric transducers and the laser interferometer are described m a sepa¬ rate section
Dust cleansing of star-forming gas

Aims. The possibility that the chemical composition of the solar atmosphere has been affected by radiative dust cleansing of late and weak accretion flows by the proto-sun itself is explored. Methods. Estimates, using semi-analytical methods and numerical simulations of the motion of dust grains in a collapsing non-magnetic and non-rotating gas sphere with a central light source are made in order to model possible dust-cleansing effects. Results. Our calculations indicate that the amount of cleansed material may well be consistent with the abundance differences observed for the Sun when compared with solar-like stars and with the relations found between these differences and the condensation temperature of the element. Conclusions. It seems quite possible that the proposed mechanism produced the significant abundance effects observed for the Sun, provided that late and relatively weak accretion did occur. The effects of cleansing may, however, be affected by outflows from the Sun, the existence and dynamics of magnetic fields and of the accretion disk, and the possible presence and location of the early Sun in a rich stellar cluster.
Performance of a combined optical coherence tomography and scanning laser ophthalmoscope with adaptive optics for human retinal imaging applications

We describe the design and performance of a recently implemented retinal imaging system for the human eye that combines adaptive optics (AO) with spectral domain optical coherence tomography (OCT) and scanning laser ophthalmoscopy (SLO). The AO-OCT-SLO system simultaneously acquires SLO frames and OCT B-scans at 60 Hz with an OCT volume acquisition scan rate of 0.24 Hz. The SLO images are used to correct for eye motion during the registration of OCT B-scans. Key optical design considerations are discussed including: minimizing system aberrations through the use of off-axis relay telescopes; choice of telescope magnification based on pupil plane requirements and restrictions; and the use of dichroic beam splitters to separate and re-combine OCT and SLO beams around the nonshared horizontal scanning mirrors. We include an analysis of closed-loop AO correction on a model eye and compare these findings with system performance in vivo. The 2D and 3D OCT scans included in this work demonstrate the ability of this system to laterally and axially resolve individual cone photoreceptors, while the corresponding SLO images show the en face mosaics at the photoreceptor layer showing rods and cones. Images from both healthy and diseased retina are presented.
Criteria of Evaluation for Systems Using Sensor as a Service

This document proposes an approach to the criteria settings for evaluation of systems that use sensors as a service through the analysis of sensor repository and search engine data. The sensor paradigm as a service is a branched concept of cloud computing, which is still evolving. Thus, to achieve the end user’s expectation for this type of service, it is necessary to define clear parameters for the evaluation of the delivery of it. The proposal presented in this paper provides an analysis based on the type of sensors and how its owner groups them in a multiuser system. Keywordssensor as a service; sensors repository; search engine data.
AN INVESTIGATION OF FACTORS AFFECTING THE AVERAGE CREDIT COLLECTION PERIOD FOR SMES SUPPLYING TO A MAJOR MUNICIPALITY IN SOUTH AFRICA – IMPLICATIONS FOR POLICY

It is widely agreed that SMEs, unlike big firms, are sensitive to specifically, among other things, changes in their cash flow position. Negative cash flows threaten the survival of SMEs and situations that create these conditions making them vulnerable are to be avoided. An example of such a situation is when there is delay in paying SMEs for goods and services rendered. While it is recognised that Government through its structures such as Local Government and Municipalities is a key customer for SMEs pre-qualified as suppliers, there are complaints that Government delays in paying its suppliers. This would seem to contradict Government policy as Government also tries through various initiatives to develop and promote SMEs. This study undertakes a survey of SMEs that supply one of the major municipalities in South Africa and investigates factors affecting the average credit collection period. A similar study in South Africa is not known. Findings from the study are expected to highlight weaknesses in the current procurement practices of South African Government structures that disadvantage SMEs, hence contradicting Government’s policy of promoting SMEs in business, which are flags for policy makers to pay attention to.
Do Cultural Differences Explain Differences in Attitudes Towards Unions? Culture and Attitudes Towards Unions Among Call Centre Workers in Britain and India

This article adds to the literature on worker attitudes towards unions by investigating the impact of cultural attitudes and the call centre labour process on union attitudes among call centre workers in Britain and India. It is hypothesised that workers with egalitarian and collectivist cultural attitudes will be more likely to have pro-union attitudes than other workers, although if the impact of cultural attitudes is mediated by history and institutions, it might be expected that this relationship is stronger for British than Indian workers. Conversely, if union attitudes are largely a function of the call centre labour process, we would expect union attitudes to be similar among workers in both countries. Our results only partially support our hypotheses. Collectivist attitudes are only weakly related to union attitudes among the British sample but are more strongly related in the Indian sample. There are significant differences between union attitudes among our British and Indian samples. The article concludes that relationship between cultural attitudes and union attitudes are heavily dependent on institutional context. Cultural attitudes are unlikely to be either a constraint or a facilitator of union efforts to organise workers.
SimilaritieS in the allocation of metallic elementS in Dietary PlantS

SImIlarItIeS IN the alloCatIoN of metallIC elemeNtS IN DIetary PlaNtS. Geografijos metrastis 45, 2012. abstract. The accumulation of metals in different plant parts may show species-specific patterns, possibly influenced by soil properties. The carrot (Daucus carota) and zucchini (Cucurbita pepo var. giromontia) were studied in five sampling areas with different soils in hungary. We wanted to know how the differ - ent soil types affected the uptake and the allocation of the examined heavy metals within the plants. The accumulation and allocation of Co, Cu, fe, mn, Ni and Zn have been assessed within these agricultural plants. We found inconsistency between allocation pattern of the plants and the metal content of the soils. We tried to reveal which among the total heavy metal contents of the soils and the attributes (ph, CaC o 3 - content, humus-content, granulometric composition) plays the most important role in the heavy metal uptake and those allocation within the plants. We found that the allocation of these elements in the select- ed dietary plants showed species-specific response. The two studied vegetables have their own allocation pattern, but both accumulate more elements in the leaves, than in the edible parts. We supposed that the examined plants would give different physiological answers in the cases of soils with different attributes. The Cu and Ni showed low variation within the plant, while Co and Zn had particular variation among the samples. The fe and mn patterns may be influenced by the different soils. In this study we revealed that the similarities found in the response of the plants bear functional character, thus they are tending to avoid the high accumulation of metals in the reservoirs/propagules regardless their species-specific purposes.
Efficient Spatial Modeling Using the SPDE Approach With Bivariate Splines

Gaussian fields (GFs) are frequently used in spatial statistics for their versatility. The associated computational cost can be a bottleneck, especially in realistic applications. It has been shown that computational efficiency can be gained by doing the computations using Gaussian Markov random fields (GMRFs) as the GFs can be seen as weak solutions to corresponding stochastic partial differential equations (SPDEs) using piecewise linear finite elements. We introduce a new class of representations of GFs with bivariate splines instead of finite elements. This allows an easier implementation of piecewise polynomial representations of various degrees. It leads to GMRFs that can be inferred efficiently and can be easily extended to nonstationary fields. The solutions approximated with higher order bivariate splines converge faster, hence the computational cost can be alleviated. Numerical simulations using both real and simulated data also demonstrate that our framework increases the flexibility and efficiency. Supplementary materials are available online.