bluuebunny/crossref_metadata_2025_split huggingface dataset:
Improvements in Thermal Efficiencies with Single-stage Reheating at High Steam Pressures and Temperatures
Authors: London J. C. 
Published: February 2019

In this paper are supplemented the data given by Baumann and by Finniecome in papers on improvements in thermal efficiencies with high steam pressures and temperatures in non-reheating plant. Except for changes necessary to cover single-stage reheating, the same basic assumptions as listed in Finniecome's paper are followed; a detailed feed-heating heat-balance is included in Appendix II as an example. Curves from Finniecome's paper, extended to higher steam conditions and showing the improvements in thermal efficiencies, non-reheating, at various pressures and temperatures, are included to preserve continuity and for comparison with single-stage reheating cycles on a common basis of 600 lb. per sq. in. gauge, 800 deg. F. non-reheating. With single-stage reheating, the effect of varying the feed-temperature at different reheat pressures is illustrated by the results of typical examples which were calculated to determine the optimum feed-temperatures. The improvements in thermal efficiencies due to reheating at various reheat pressures are plotted for stop-valve steam pressures of 900, 1,200, 1,500, and 2,000 lb. per sq. in. gauge; the loss when reheating to a temperature which is 50 deg. F. below the stop-valve temperature is also indicated. The thermal performances reheating and non-reheating, relative to 600 lb. per sq. in. gauge, 800 deg. F., non-reheating, are included; the improvement in thermal efficiency due to reheating is plotted against stop-valve pressure with initial and reheat steam temperatures as parameters for a reheat pressure which is 25 per cent of the stop-valve pressure. The effects of changing certain basic assumptions (such as the pressure drop across the reheater and the vacuum) are stated; wetness values at exhaust reheating and non-reheating are given for comparison.
Scale Formation in Sea-water Distilling Plants and its Prevention
Authors: Hillier H. 
Published: February 2019

The scales found in sea-water evaporators are formed of calcium sulphate, calcium carbonate, and magnesium hydroxide. Calcium sulphate scale can be avoided by using a sufficiently dilute brine concentration to maintain the sulphate in solution. The conditions are indicated under which the formation of this scale can be avoided. Calcium carbonate and magnesium hydroxide scales are shown to be due to the carbonate alkalinity in the sea water, which is limited and reasonably constant. These scales are due to the break-up of the bicarbonate ions in the sea-water as heating and boiling occur. Up to a well-defined range of operating temperatures, a scale that is predominantly of calcium carbonate is experienced. At higher temperatures, a scale predominantly of magnesium hydroxide is formed; but both types of scale may occur in the region of the change-over zone. It is shown that the break-up of the bicarbonate ions produces carbonate ions, which give rise to the calcium carbonate scale and that, with further heating and boiling, break-up of the carbonate ions occurs with the formation of hydroxyl ions, which combine with magnesium ions to form the magnesium hydroxide scale. It is shown that some of the alkalinity leaves the evaporator with the blow-down; as calcium carbonate in solution, or calcium carbonate and/or magnesium hydroxide in suspension. The amount of scale formed is found to be proportional to the amount of sea-water used, and no benefit is obtained by operating at low brine densities. It is shown that the rate of scale formation is greater for low temperatures than high temperatures, and increases with the temperature difference across the heating surface. Tests show that the use of organic dispersive compounds gives rise to a weaker scale structure, which allows some of the scale to be shed by cracking. The calcium carbonate and magnesium hydroxide scales can be completely prevented if the appropriate quantity of hydrogen ions is supplied by the injection of acids such as hydrochloric acid or sulphuric acid, or an acid salt such as sodium bisulphate. These scales can also be prevented by the injection of ferric chloride, which provides a supply of ferric ions. The ferric ions combine preferentially with the hydroxyl ions formed by the break-up of the bicarbonate and carbonate ions— thus allowing the formation of ferric hydroxide, which is very insoluble and is maintained in suspension in the brine without forming scale. Long-period tests on large commercial plants have confirmed the research tests.
Wave Action following the Sudden Release of Air through an Engine Port System
Authors: Wallace F. J. , Stuart Mitchell R. W. 
Published: February 2019

As an intermediate step in the analysis of the scavenging process in two-stroke engines, a ported opposed-piston engine liner, discharging cold air through the exhaust ports into a conventional exhaust system, is considered. The ports are sealed by cellophane membranes which, when pierced by a solenoid-operated needle, give a sudden discharge. The process of discharge, wave propagation in the exhaust pipe, and partial evacuation of the cylinder by the returning rarefaction wave, is analysed by methods developed from the work of Bannister and Mucklow (1948)‡ on waves of finite amplitude, and good agreement between the experimental and theoretical investigation is obtained, particularly with regard to the duration and magnitude of the depression in the cylinder. In addition, the coefficient of discharge of the exhaust ports is examined under different release conditions and a relation, based on dimensional analysis, is established from which a coefficient of discharge under any given set of operating conditions may be deduced. The results of the present investigation may be summarized under three headings:—( 1) Wave Action. The various phenomena associated with the discharge of compressed gas from the cylinder into the pipe through the exhaust ports may be accounted for satisfactorily by an extension of the theory of waves of finite amplitude. ( 2) Coefficient of Discharge. The coefficient of discharge of the exhaust ports varies with cylinder pressure, port opening, and temperature, and a general relation, based on dimensional analysis, is established between the coefficient of discharge and these variables. ( 3) Depression in the Cylinder. The duration and magnitude of the depression in the cylinder following wave action in the exhaust pipe may be evaluated satisfactorily with the aid of a step-by-step analysis based on the finite wave theory. While there is no scavenging action, in the accepted sense, in the experimental apparatus, owing to the permanently closed inlet ports, the present analysis may readily be extended to simultaneous flow through the inlet and exhaust ports, as it occurs in the running engine.
Instruction and Research in Hydraulic Laboratories
Authors: Addison Herbert 
Published: February 2019

In this paper, after the mention of alternative policies that might control the planning and conduct of instructional laboratories in general, it is suggested how either of these policies might be adapted to hydraulic laboratories. Probably because of these diverse possibilities there seems to be no accepted or standardized layout for such laboratories. Nevertheless, it might be possible to derive guidance from the record of development in one particular technological institution, showing how equipment and operation have responded to changing circumstances. The institution chosen for study in the paper is the Faculty of Engineering of the Fouad I University, Giza, Egypt, where, twice within the space of thirty years, the staff have had the opportunity of planning completely new hydraulic laboratories. Some units of experimental equipment are described, and comments are added giving the results of experience in the conduct of the laboratories. To show the interrelation between instruction and research in such an institution, the findings of some post-graduate research projects carried out there are summarized.
An Experimental Investigation into the Redrawing of Cylindrical Shells
Authors: Chung S. Y. , Swift H. W. 
Published: February 2019

Cups having a height/diameter ratio greater than unity cannot as a rule be produced from flat circular blanks in a single stage, and redrawing in one or more operations has to be carried out until the desired shape of the shell is attained. In this paper an account is given of an experimental investigation into the forces, work, and strains involved in the first redrawing process. The work was carried out in an experimental crank press (Seed and Swift 1950)‡ of 50 tons nominal capacity, and was based on a first-stage cup diameter of 4 inches. Brass, mild steel and aluminium (in two tempers) were used. The conditions examined include the direct and reverse methods of redrawing, first-stage drawing ratio, inter-stage heat-treatment, punch profile radius, first-stage punch-die clearance, redrawing ratio, blank thickness, material, and temper. It is thought that the results are sufficiently accurate and detailed to give a reasonably complete insight into the redrawing process, and conclusions have been drawn to assist press-tool engineers in the design of drawing tools.
Experiments on Short-radius Pipe-bends
Authors: Gross Nicol 
Published: February 2019

A series of experiments on short-radius pipe-bends of seamless and welded types is described, the objective being to compare the strength and flexibility of the two kinds of pipe-bends under different forms of loading. To do this rationally, it was necessary to establish whether the existing theory for curved tubes could be applied to the short-radius bend, where the pipe radius is not negligible as compared with the radius of curvature. The validity of existing theory and of a suggested extension to it was checked by carrying out extensive measurements of the stresses and deformations in pipe-bends subjected to the test loading. The results are given in two sections: (1) bending of short-radius pipe-bends (without internal pressure), and (2) stresses in short-radius pipe-bends subjected to internal pressure.
Recent Developments in the Machinability of Steel
Authors: Wolfe K. J. B. 
Published: February 2019

A description of the term “machinability” is given, and it is shown that the behaviour of the metal being machined, called “true machinability”, and also the conduct of the tool, known as “cutability”, are separate and distinct factors in the metal cutting process. The action of cutting-fluids is shown to be a modifying factor. Recent work at one laboratory in the field of “true machinability” is described, and includes the effects on this property of hardness, rate of work hardening, microstructure, manganese segregations, and the size of lead globules. The effects on surface finish of speed in turning and some aspects of interest which arise under conditions of intermittent cutting, such as shaping, are included. Under new work on “cutability” is mentioned the modifying effect on that factor of surface austenite, produced by grinding, and metallic segregations, as shown by micro-radiography. A general description is given of the properties and performance of milling cutters produced by a casting process. Developments in the field of cutting-fluids are noted. Future trends in the developments of all the important fields of machinability are especially discussed, in view of the present alloy shortage. The use of ceramic materials and low tungsten and molybdenum high-speed steels as cutting-tool materials is mentioned, and also the application of new cutting techniques such as the “hot spot” and electrolytic/electro-erosion methods. Suggestions are made for improvements in both machining stock and cutting-fluids.
A Photo-elastic Study of Stresses in Screw Threads
Authors: Brown A. F. C. , Hickson V. M. 
Published: February 2019

The several components of the deformation of a screw subjected to tension through a nut have been examined theoretically by Sopwith (1948)‡. He showed that the distribution of load along the thread was far from uniform and that it reached its maximum intensity at the plane of the bearing face of the nut. Sopwith's conclusions have now been investigated photo-elastically with a Fosterite model of a stud and nut, using the “frozen-stress” method. An additional investigation was made of the stress distribution in a tension nut with a recessed stud, suggested by Sopwith as a means of rendering the load distribution more uniform. The experimental results confirm the theory in both cases, showing a large rise in stress in the stud near the bearing face of the ordinary nut and a much more uniform distribution of stress when the tension nut is used. The stress concentration factors determined for the normal nut are higher than those found by Hetényi, who used Bakelite B.T.61-893 as the model material. This difference may be accounted for partly by improvements in technique and partly by the greater accuracy which becomes possible with the use of Fosterite.
“Frozen Stress” Phenomenon in Photo-elasticity
Authors: Fessler H. 
Published: February 2019

Tensile tests were carried out at different temperatures and under different stresses on “Marco Resin SB. 26c”, “Fosterite”, and “Bakelite”. Loads were applied through hinged pads acting on inclined faces at the ends. The separate existence of an “instantaneous”† (room temperature) as well as a “delayed” (“frozen”) optical effect was proved for Marco. “Hot delayed” fringe orders (fringe reading at test temperature—no load fringe order at test temperature—corresponding instantaneous fringe order) are distinguished from “residual” fringe orders (fringe order after freezing cycle—fringe order before). Hot delayed and residual fringe orders and strains were found to be proportional to stress at all temperatures tested. Fringe orders and strains showed maximum values at certain temperatures. An increase in fringe order during cooling under constant stress was observed in Fosterite and Bakelite. Except for this and the opposite sense of instantaneous and delayed fringe orders in Marco and Fosterite, the three materials behaved similarly.
The role of information and communications technology in the transformation of government and citizen trust
Authors: Mahmood Mohamed , Weerakkody Vishanth , Chen Weifeng 
Published: February 2019

We present an empirically tested conceptual model based on exit–voice theory to study the influence of information and communications technology-enabled transformation of government on citizen trust in government. We conceptualize and address the key factors affecting the influence of transformation of government on citizen trust, including government performance and transparency. Based on 313 survey responses from citizens in Bahrain, the top-ranked country in information and communications technology adoption in the Gulf Cooperation Council region, we test government performance and transparency as mediators between transformation of government and citizen trust. The resulting preliminary insights on the measurement and manifestation of citizen trust in the context of information and communications technology-enabled transformation of government have multiple policy implications and extend our understanding of how information and communications technology-enabled transformation of government can improve the government–citizen relationship and digital services adoption. Points for practitioners To fundamentally change the core functions of government, information and communications technology-enabled transformation of government must move beyond the simple digitization and web enabling of processes. Information and communications technology-enabled transformation of government has the potential to address declining citizen trust in government by improving transparency and performance. The success of information and communications technology-enabled transformation of government in Bahrain is attributable to its small size and demographic composition, the relative maturity of digital government initiatives, and the complete commitment of the government to information and communications technology-enabled transformation of government.
An Exploratory Study of Reading Mathematical Expressions by Braille Readers
Authors: van Leendert Annemiek , Doorman Michiel , Drijvers Paul , Pel Johan , van der Steen Johannes 
Published: February 2019

Introduction: Braille readers encounter difficulties when reading mathematical expressions. In this exploratory study, we created a setting to investigate these difficulties. Method: Using a motion-capturing system, we analyzed the tactile strategies of three braille readers while they read mathematical expressions. To compare tactile with visual reading strategies, we also analyzed the oculomotor performance in five print readers. Results: The analysis showed that the two experienced braille readers needed about 3.5 times as much time as print readers to read and solve four items involving mathematical expressions. The braille readers used personal reading strategies for all items with little use of the structure of the expression. In contrast, the reading strategies of print readers showed item-dependent and structure-related characteristics. Discussion: The braille readers had difficulties, within the constraints of tactile reading, to align their reading strategies with the solution procedures required by the mathematical structure of the items. Implications for practitioners: Teachers need to become aware of the kind of problems that braille readers confront when they try to comprehend and solve mathematical problems.
Effectiveness of a programme comprising serial casting, botulinum toxin, splinting and motor training for contracture management: a randomized controlled trial
Authors: Leung Joan , King Clayton , Fereday Sarah 
Published: February 2019

Objective: To determine the effectiveness of a programme comprising serial casting, botulinum toxin, splinting and motor training in contracture management. Design: A randomized trial with concealed allocation and assessor blinding, a deferred treatment cross-over design within the control group, was conducted. Setting: Inpatient Brain Injury Unit of a rehabilitation centre. Subjects: A total of 10 patients with severe acquired brain injury (13 ankles). Interventions: The intervention group received botulinum toxin and then serial casting. The control group was placed on a wait list for six weeks (control phase) and then received the same interventions as the intervention group (intervention phase). Both groups received splinting and motor training following serial casting. Main measures: The primary outcome was passive ankle dorsiflexion range. Secondary outcomes included spasticity, ankle dorsiflexor strength, Functional Independence Measure score for the walking item and walking speed. Results: The mean between-group difference for passive ankle dorsiflexion range at completion of casting was 26° (95% confidence interval (CI): 17–35); at Week 2, after casting was 24° (95% CI: 14–33). The mean within-group differences for passive ankle dorsiflexion at completion of casting, Week 2 after casting and Week 8 after casting were 26° (95% CI: 20–31), 26° (95% CI: 18–33) and 24° (95% CI: 19–30), respectively. These improvements were sustained at Week 2 and Week 8 after casting. Conclusions: A programme for contracture management comprising serial casting, botulinum toxin, motor training and splinting can be useful in improving joint range.
Prevalence and epidemiological associates of novel psychedelic use in the United States adult population
Authors: Sexton James D , Crawford Michael S , Sweat Noah W , Varley Allyson , Green Emma E , Hendricks Peter S 
Published: February 2019

Background: Novel psychedelics approximate classic psychedelics, but unlike classic psychedelics, novel psychedelics have been used by humans for a shorter period of time, with fewer data available on these substances. Aims: The purpose of this study was to determine the prevalence of novel psychedelic use and the associations of novel psychedelic use with mental health outcomes. Methods: We estimated the prevalence of self-reported, write-in lifetime novel psychedelic use and evaluated the associations of novel psychedelic use with psychosocial characteristics, past month psychological distress, and past year suicidality among adult respondents pooled from years 2008–2016 of the National Survey on Drug Use and Health (weighted n=234,914,788). Results: A fraction (weighted n=273,720; 0.12%) reported lifetime novel psychedelic use. This cohort tended to be younger, male, and White, have greater educational attainment but less income, be more likely to have never been married, engage in self-reported risky behavior, and report lifetime illicit use of other drugs, particularly classic psychedelics (96.9%). (2-(4-Bromo-2,5-dimethoxyphenyl)ethanamine) (2C-B) (30.01%), (2,5-dimethoxy-4-iodophenethylamine) (2C-I) (23.9%), and (1-(2,5-dimethoxy-4-ethylphenyl)-2-aminoethane) (2C-E) (14.8%) accounted for the majority of lifetime novel psychedelic use. Although lifetime novel psychedelic use was not associated with psychological distress or suicidality compared to no lifetime novel psychedelic use or classic psychedelic use, relative to lifetime use of classic psychedelics but not novel psychedelics, lifetime novel psychedelic use was associated with a greater likelihood of past year suicidal thinking (adjusted Odds Ratio (aOR)=1.4 (1.1–1.9)) and past year suicidal planning (aOR=1.6 (1.1–2.4)). Conclusion: Novel psychedelics may differ from classic psychedelics in meaningful ways, though additional, directed research is needed.
A prospective randomized trial of a potassium competitive acid blocker vs proton pump inhibitors on the effect of ulcer healing after endoscopic submucosal dissection of gastric neoplasia
Authors: Komori Hiroyuki , Ueyama Hiroya , Nagahara Akihito , Akazawa Yoichi , Takeda Tsutomu , Matsumoto Kohei , Matsumoto Kenshi , Asaoka Daisuke , Hojo Mariko , Yao Takashi , Watanabe Sumio 
Published: February 2019

Background/Aims Vonoprazan is a new a potassium-competitive acid blocker (P-CAB) that was recently developed in Japan. However, vonoprazan’s efficacy in healing gastric ulcers after endoscopic submucosal dissection (ESD) remains controversial. This study aimed to compare the efficacy of P-CABs and proton pump inhibitors (PPIs) in healing post-ESD ulcers. Materials and Methods This prospective randomized controlled trial (UMIN000017386) enrolled 40 patients with gastric neoplasia, who underwent ESD at our hospital from April 2015 to January 2016. Before ESD, patients were randomly divided into the following two groups: group V, vonoprazan 20 mg/day; or group R, rabeprazole 10 mg/day. Medications were taken 1 day before to 4 weeks after ESD. The ESD-induced artificial ulcer size was measured just after ESD and 4 weeks after ESD to calculate the reduction rate as follows: (ulcer area 4 weeks after ESD)/(ulcer area just after ESD) × 100. Results Eighteen patients in group V and 15 patients in group R were analyzed. The mean reduction rate was significantly different in groups V and R (93.3% vs 96.6%, respectively). Post-ESD bleeding was observed in two patients in group R and drug-induced hepatic injury in one patient in group R. Conclusion Rabeprazole facilitated the healing process post-ESD.