scholarly journals Robert Abbott Hadfield, 1858 - 1940

1941 ◽  
Vol 3 (10) ◽  
pp. 647-664 ◽  
Keyword(s):  
Small Scale ◽  
General Belief ◽  
Interest In Science ◽  
Great Saving ◽  
International Exhibitions ◽  
Steel Castings ◽  
Hydraulic Cylinders ◽  
Second Year ◽  
Set Up ◽  
Steel Projectiles

Robert Abbott Hadfield, head of the great steel firm bearing his name, died at his house on Kingston Hill on 30 September 1940, in his eighty-second year. He was born at Attercliffe, then still a village, on 28 November 1858, and came of a Derbyshire family which had long been connected with Sheffield. His father, Robert Hadfield, who had gained experience in several branches of the steel industry, at that time carried on on a small scale, in 1872 set up a works with the special object of making steel castings, then a novelty in this country, although practised on the Continent. The enterprise was considered rather rash, on account of a general belief that steel must be forged before it could acquire such mechanical properties as to make it a trustworthy material, but it proved very successful, and the castings, which included such large objects as hydraulic cylinders, showing a great saving of weight over cast iron, gained medals at several international exhibitions. The firm also produced steel projectiles, which until then had only been manufactured in France. Robert Hadfield declined to buy foreign patents for these, and developed their production independently, thus laying the foundation of what was to become one of the leading armament firms. His son attended the Collegiate School in Sheffield, and was taught chemistry by William Baker, whose lecture demonstrations seem to have attracted him. His interest in science was stimulated by reading Pepper’s Playbook of Science and Playbook of Metals , two excellent books which must have influenced the careers of many boys.

scholarly journals Modification of a Solar Thermal Collector to Promote Heat Transfer inside an Evacuated Tube Solar Thermal Absorber

2021 ◽  
Vol 11 (9) ◽  
pp. 4100
Author(s):  
Rasa Supankanok ◽  
Sukanpirom Sriwong ◽  
Phisan Ponpo ◽  
Wei Wu ◽  
Walairat Chandra-ambhorn ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Pipe ◽  
Solar Thermal ◽  
Heat Transfer Fluid ◽  
Small Scale ◽  
Medium Temperature ◽  
Change Behavior ◽  
Set Up ◽  
Evacuated Tube ◽  
Heating Medium

Evacuated-tube solar collector (ETSC) is developed to achieve high heating medium temperature. Heat transfer fluid contained inside a copper heat pipe directly affects the heating medium temperature. A 10 mol% of ethylene-glycol in water is the heat transfer fluid in this system. The purpose of this study is to modify inner structure of the evacuated tube for promoting heat transfer through aluminum fin to the copper heat pipe by inserting stainless-steel scrubbers in the evacuated tube to increase heat conduction surface area. The experiment is set up to measure the temperature of heat transfer fluid at a heat pipe tip which is a heat exchange area between heat transfer fluid and heating medium. The vapor/ liquid equilibrium (VLE) theory is applied to investigate phase change behavior of the heat transfer fluid. Mathematical model validated with 6 experimental results is set up to investigate the performance of ETSC system and evaluate the feasibility of applying the modified ETSC in small-scale industries. The results indicate that the average temperature of heat transfer fluid in a modified tube increased to 160.32 °C which is higher than a standard tube by approximately 22 °C leading to the increase in its efficiency by 34.96%.

Numerical Study of Methane and Air Combustion Inside Heat-Recirculating Combustors

2013 ◽  
Author(s):  
Yanxia Li ◽  
Zhongliang Liu ◽  
Yan Wang ◽  
Jiaming Liu
Keyword(s):  
Gas Flow ◽  
Numerical Study ◽  
Convection Heat Transfer ◽  
Central Area ◽  
Small Scale ◽  
Inlet Velocity ◽  
Strong Convection ◽  
Simulation Results ◽  
Lean Fuel ◽  
Set Up

A numerical model on methane/air combustion inside a small Swiss-roll combustor was set up to investigate the flame position of small-scale combustion. The simulation results show that the combustion flame could be maintained in the central area of the combustor only when the speed and equivalence ratio are all within a narrow and specific range. For high inlet velocity, the combustion could be sustained stably even with a very lean fuel and the flame always stayed at the first corner of reactant channel because of the strong convection heat transfer and preheating. For low inlet velocity, small amounts of fuel could combust stably in the central area of the combustor, because heat was appropriately transferred from the gas to the inlet mixture. Whereas, for the low premixed gas flow, only in certain conditions (Φ = 0.8 ～ 1.2 when ν0 = 1.0m/s, Φ = 1.0 when ν0 = 0.5m/s) the small-scale combustion could be maintained.

Small Scale Supercritical CO2 Radial Inflow Turbine Meanline Design Considerations

2018 ◽  
Author(s):  
Tina Unglaube ◽  
Hsiao-Wei D. Chiang
Keyword(s):  
High Velocity ◽  
Gas Turbines ◽  
Velocity Ratio ◽  
Maximum Efficiency ◽  
Design Parameters ◽  
Working Fluid ◽  
Small Scale ◽  
Optimum Velocity ◽  
Set Up ◽  
Very High

In recent years closed loop supercritical carbon dioxide Brayton cycles have drawn the attention of many researchers as they are characterized by a higher theoretic efficiency and smaller turbomachinery size compared to the conventional steam Rankine cycle for power generation. Currently, first prototypes of this emerging technology are under development and thus small scale sCO2 turbomachinery needs to be developed. However, the design of sCO2 turbines faces several new challenges, such as the very high rotational speed and the high power density. Thus, the eligibility of well-established radial inflow gas turbine design principles has to be reviewed regarding their suitability for sCO2 turbines. Therefore, this work reviews different suggestion for optimum velocity ratios for gas turbines and aims to re-establish it for sCO2 turbines. A mean line design procedure is developed to obtain the geometric dimensions for small scale sCO2 radial inflow turbines. By varying the specific speed and the velocity ratio, different turbine configurations are set up. They are compared numerically by means of CFD analysis to conclude on optimum design parameters with regard to maximum total-to-static efficiency. Six sets of simulations with different specific speeds between 0.15 and 0.52 are set up. Higher specific speeds could not be analyzed, as they require very high rotational speeds (more than 140k RPM) for small scale sCO2 turbines (up to 150kWe). For each set of simulations, the velocity ratio that effectuates maximum efficiency is identified and compared to the optimum parameters recommended for radial inflow turbines using subcritical air as the working fluid. It is found that the values for optimum velocity ratios suggested by Rohlik (1968) are rather far away from the optimum values indicated by the conducted simulations. However, the optimum values suggested by Aungier (2005), although also established for subcritical gas turbines, show an approximate agreement with the simulation results for sCO2 turbines. Though, this agreement should be studied for a wider range of specific speeds and a finer resolution of velocity ratios. Furthermore, for high specific speeds in combination with high velocity ratios, the pressure drop of the designed turbines is too high, so that the outlet pressure is beyond the critical point. For low specific speeds in combination with low velocity ratios, the power output of the designed turbines becomes very small. Geometrically, turbines with low specific speeds and high velocity ratios are characterized by very small blade heights, turbines with high specific speeds and small velocity ratios by very small diameters.

LO.CO.MO.DIA: Low Cost Monitoring for Diagnostic Purposes of a Small Scale CHP Plant

2000 ◽  
Author(s):  
Francesco Fantozzi ◽  
Umberto Desideri
Keyword(s):  
Data Acquisition ◽  
Internal Combustion Engines ◽  
Low Cost ◽  
Small Scale ◽  
Combustion Engines ◽  
Performance Indexes ◽  
Data Acquisition Board ◽  
Set Up ◽  
The University ◽  
Maintenance Personnel

Abstract Small scale Internal Combustion Engines (ICE) powered Combined Heat and Power (CHP) plants are economically convenient when availability and efficiencies are above specified limits. Nevertheless these plants are often run without a monitoring device capable of data storing and trending and of performance evaluation. This paper describes the setting up of a powerful low-cost monitoring system for the CHP plant that powers the School of Engineering of the University of Perugia. Data acquisition is performed by interfacing a Personal Computer (PC) to existing control panels via, serial port, and to a data acquisition board for those variables that are not measured by existing devices. Performance indexes are then calculated via software. Alarms and controls are stored as well to set up a database for diagnostic purposes. The monitoring itself has already shown its troubleshooting capability in interface to maintenance personnel: history trending of variables speeds up the phase of failure identification because it eliminates those possibilities that are negated by cross referencing values of different variables.

Small-Scale Gradients in Big River: Implications for a State-of-the-Art Research Platform in the Elbe

2021 ◽  
Author(s):  
Sina Bold ◽  
Justus E.E. van Beusekom ◽  
Yoana G. Voynova ◽  
Marius Cysewski ◽  
Bryce Van Dam ◽  
...  
Keyword(s):  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Ammonium Phosphate ◽  
Total Alkalinity ◽  
Small Scale ◽  
Suspended Particulate ◽  
Research Platform ◽  
Biogeochemical Parameters ◽  
Art Research ◽  
Set Up

<p>Estuaries are crucial in transforming matter fluxes from land to sea. To better understand and quantify these processes and respective fluxes, it is important to determine the input into an estuary accurately. To allow for such studies in the Elbe estuary in Germany, a state-of-the-art research platform is currently being set-up just upstream of the weir in Geesthacht at the entrance of the estuary. Here, we report on small-scale spatial dynamics of organic matter and associated processes from several cross and longitudinal profiles around the planned location and the implications for the set-up of the aforementioned research platform.</p><p>Based on preliminary data obtained in August 2020 during a period of relatively low discharge, we present the following results: (1) In three cross profiles along a 10 km transect of the Elbe upstream of the weir, we observed considerable small-scale gradients regarding currents and various biogeochemical parameters. In comparison to the fairway, water from the riverbanks was depleted in suspended particulate matter, chlorophyll a, dissolved oxygen, and nitrate, and enhanced in ammonium, phosphate and silicate, as well as total alkalinity and dissolved inorganic carbon paralleled by decreasing pH. This suggests that in the summer, organic matter is deposited and remineralised at the riverbanks, resulting in the release of ammonium, phosphate and silicate, and in the removal of nitrate, presumably by denitrification. (2) Along the 10 km transect towards the weir, we observed that concentrations of suspended particulate matter, chlorophyll a, dissolved oxygen, nitrate and pH were decreasing. In contrast, we found that ammonium, phosphate and silicate, total alkalinity and dissolved inorganic carbon increased towards the weir. This suggests an increased sedimentation and subsequent remineralisation due to the reduced flow velocities in front of the weir. (3) An analysis of a 10-year time series from the weir supports this by showing higher ammonium concentrations when discharges were relatively low. The implications of these findings for the set-up of the research platform in this area, as well as for optimising estimates of budgets are discussed. The research platform will contribute to understand further such variations in biogeochemical parameters at the entrance of the Elbe estuary over time.</p><p>The research platform is set-up in cooperation with the Helmholtz initiative MOSES (“Modular Observation Solutions for Earth Systems“) and will be incorporated in the Elbe-North Sea Supersite of DANUBIUS-RI (“International Centre for Advanced Studies on River-Sea Systems“). Funding is provided by European Regional Development Funds, the federal state of Schleswig-Holstein, the Helmholtz Association and the Helmholtz-Zentrum Geesthacht. The research platform, planned to be operational in autumn 2021, will also be open for users e.g. to develop and test new methods and technologies. Data will be made available through the “Helmholtz Coastal Data Centre” (HCDC).</p>

The emergence of family entrepreneurship in the transition economy of Cuba

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Eli Gimmon ◽  
Christian Felzensztein
Keyword(s):  
Transition Economies ◽  
Transition Economy ◽  
Small Scale ◽  
Entrepreneurial Firms ◽  
Content Type ◽  
Private Data ◽  
Set Up ◽  
Available Information ◽  
Depth Interviews ◽  
Family Entrepreneurship

PurposeTo better understand the emergence of small-scale entrepreneurial firms in the under-researched transition economy of Cuba.Design/methodology/approachGiven the scarcity of reliable publicly available information and restrictions on private data collection in Cuba, in-depth interviews were conducted with a panel of small-scale entrepreneurs at three different points in time. Evolutions are analyzed over this period.FindingsFamily can overcome institutional constraints by helping the entrepreneur deal with market and social obstacles. Despite the absence of a supportive entrepreneurial ecosystem, these new entrepreneurs and their families have been able to transform longstanding passive attitudes into positive steps to set up new small-scale ventures in a country facing unprecedented internal and external challenges.Originality/valueA new conceptual model of family support for entrepreneurship in transition economies is presented. The findings lend weight to institutional theory on overcoming constraints in emerging markets and extend the theory of family entrepreneurship to new transition economies.

Leveraging the Cloud for Large-Scale Software Testing – A Case Study

2012 ◽  
pp. 252-279 ◽  
Author(s):  
Anjan Pakhira ◽  
Peter Andras
Keyword(s):  
Large Scale ◽  
Analysis Data ◽  
System Level ◽  
Small Scale ◽  
Test Cases ◽  
Software Life Cycle ◽  
Technical Issues ◽  
Wide Scale ◽  
Set Up

Testing is a critical phase in the software life-cycle. While small-scale component-wise testing is done routinely as part of development and maintenance of large-scale software, the system level testing of the whole software is much more problematic due to low level of coverage of potential usage scenarios by test cases and high costs associated with wide-scale testing of large software. Here, the authors investigate the use of cloud computing to facilitate the testing of large-scale software. They discuss the aspects of cloud-based testing and provide an example application of this. They describe the testing of the functional importance of methods of classes in the Google Chrome software. The methods that we test are predicted to be functionally important with respect to a functionality of the software. The authors use network analysis applied to dynamic analysis data generated by the software to make these predictions. They check the validity of these predictions by mutation testing of a large number of mutated variants of the Google Chrome. The chapter provides details of how to set up the testing process on the cloud and discusses relevant technical issues.

Leveraging the Cloud for Large-Scale Software Testing

2015 ◽  
pp. 1175-1203
Author(s):  
Anjan Pakhira ◽  
Peter Andras
Keyword(s):  
Cloud Computing ◽  
Large Scale ◽  
Analysis Data ◽  
System Level ◽  
Small Scale ◽  
Test Cases ◽  
Software Life Cycle ◽  
Technical Issues ◽  
Wide Scale ◽  
Set Up

Testing is a critical phase in the software life-cycle. While small-scale component-wise testing is done routinely as part of development and maintenance of large-scale software, the system level testing of the whole software is much more problematic due to low level of coverage of potential usage scenarios by test cases and high costs associated with wide-scale testing of large software. Here, the authors investigate the use of cloud computing to facilitate the testing of large-scale software. They discuss the aspects of cloud-based testing and provide an example application of this. They describe the testing of the functional importance of methods of classes in the Google Chrome software. The methods that we test are predicted to be functionally important with respect to a functionality of the software. The authors use network analysis applied to dynamic analysis data generated by the software to make these predictions. They check the validity of these predictions by mutation testing of a large number of mutated variants of the Google Chrome. The chapter provides details of how to set up the testing process on the cloud and discusses relevant technical issues.

Breaking machines with a pencil

2017 ◽  
Author(s):  
Mavis Batey
Keyword(s):  
Small Scale ◽  
Cambridge University ◽  
Winston Churchill ◽  
Alan Turing ◽  
International Reputation ◽  
The Government ◽  
Set Up ◽  
First World ◽  
Intelligence Service ◽  
Hunting Ground

Dilly Knox, the renowned First World War codebreaker, was the first to investigate the workings of the Enigma machine after it came on the market in 1925, and he developed hand methods for breaking Enigma. What he called ‘serendipity’ was truly a mixture of careful observation and inspired guesswork. This chapter describes the importance of the pre-war introduction to Enigma that Turing received from Knox. Turing worked with Knox during the pre-war months, and when war was declared he joined Knox’s Enigma Research Section at Bletchley Park. Once a stately home, Bletchley Park had become the war station of the Secret Intelligence Service (SIS), of which the Government Code and Cypher School (GC&CS) was part. Its head, Admiral Sir Hugh Sinclair, was responsible for both espionage (Humint) and the new signals intelligence (Sigint), but the latter soon became his priority. Winston Churchill was the first minister to realize the intelligence potential of breaking the enemy’s codes, and in November 1914 he had set up ‘Room 40’ right beside his Admiralty premises. By Bletchley Park’s standards, Room 40 was a small-scale codebreaking unit focusing mainly on naval and diplomatic messages. When France and Germany also set up cryptographic bureaux they staffed them with servicemen, but Churchill insisted on recruiting scholars with minds of their own—the so-called ‘professor types’. It was an excellent decision. Under the influence of Sir Alfred Ewing, an expert in wireless telegraphy and professor of engineering at Cambridge University, Ewing’s own college, King’s, became a happy hunting ground for ‘professor types’ during both world wars—including Dillwyn (Dilly) Knox (Fig. 11.1) in the first and Alan Turing in the second. Until the time of Turing’s arrival, mostly classicists and linguists were recruited. Knox himself had an international reputation for unravelling charred fragments of Greek papyri. Shortly after Enigma first came on the market in 1925, offering security to banks and businesses for their telegrams and cables, the GC&CS obtained two of the new machines, and some time later Knox studied one of these closely.

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