scholarly journals Pengaruh Geometri Gerigi dan Kecepatan Putar Terhadap Kinerja Mesin Parut Sagu Tipe Silinder

2021 ◽  
Vol 10 (3) ◽  
pp. 413
Author(s):  
Darma Darma ◽  
Reniana Reniana ◽  
Budi Santoso ◽  
Jhonson Waromi
Keyword(s):  
Large Scale ◽  
Rotation Speed ◽  
Geometrical Shape ◽  
Two Factors ◽  
Starch Yield ◽  
Cylinder Rotation

Sago rasping machine or sago rasper is the most commonly used in sago processing both for small and large scale. It function is to reduce the size or to disintegrate sago pith into smaller particle.  By doing so, the starch contained in the pith can be separated in the subsequent process.  The amount of starch resulted depend on the size of rasped pith.  The smaller the pith is rasped the higher the starch can be extracted.  The purpose of this research was to test the effect of teeth geometrical shape and cylinder rotation speed on performance of sago rasping machine. There are four type of teeth geometrical shape namely cylinder, pyramid, screw, and cube and three levels of cylinder rotation speed they are 1500 rpm, 2000 rpm and 2500 rpm were tested. Results showed that the rasping capacity was affected significantly by the two single factors as well as its interaction of teeth geometrical shape and cylinder rotation speed. Similarly, starch yield and starch losses in waste were significantly affected by teeth geometrical shape.  Meanwhile, starch yield and starch losses in waste were not affected significantly by cylinder rotation speed and the interaction of the two factors. The best performance was resulted at the treatment of teeth geometrical shape of screw with the speed of cylinder rotation 2500 rpm.  The  performances at the treatment were: (a) rasping capacity was 918 kg/h, (b) starch yield was 48%, (wb), (c) starch loss in waste was15.1%.Keywords:  cylinder type, rasping performance, sago rasping machine, teeth geometry 

scholarly journals Performance Test of Various Teeth Diameter of Cylinder Type Sago Rasping Machine

2021 ◽  
Vol 8 (3) ◽  
pp. 113-122
Author(s):  
Darma Darma
Keyword(s):  
Traditional Method ◽  
Performance Test ◽  
Rotation Speed ◽  
Sago Starch ◽  
Two Factors ◽  
Time And Energy ◽  
Cylinder Rotation

Traditional method of sago starch extraction was a time and labor intensive process. The most laborious stage is pith disintegration which is done by using hammer-like tools called pounder. However, the use of rasping machine to disintegrate the pith is saving time and energy significantly. The objective of this study was to investigate the effect of teeth diameter and cylinder rotation speed on performance of cylinder type sago rasping machine. In the experiment, four variations of teeth diameter i.e. 3mm, 4 mm, 5 mm and 6 mm, and three levels of cylinder rotation speed i.e. 1500 rpm, 2000 rpm and 2500 rpm were examined. Results showed that both teeth diameter and cylinder rotation speed significantly affect the rasping capacity. Likewise teeth diameter also significantly affect on starch percentage and starch losses in waste.  Meanwhile, cylinder rotation speed and the interaction of the two factors have no significant effect on the starch percentage and starch loss in waste. The highest performance was obtained at the condition of teeth diameter 3 mm with cylinder rotation speed of 2500 rpm.  The performance of the machine at the condition were (a) rasping capacity 2282 kg h-1, (b) starch percentage 33.02 %, (wb), (c) starch loss in waste 8.77 %.

scholarly journals Influence of the Upstream Terrain on the Formation of a Cold Frontal Snowband in Northeast China

2021 ◽  
Author(s):  
Na Li ◽  
Baofeng Jiao ◽  
Lingkun Ran ◽  
Zongting Gao ◽  
Shouting Gao
Keyword(s):  
Gravity Waves ◽  
Northeast China ◽  
Large Scale ◽  
Control Experiment ◽  
Vertical Motion ◽  
Near Surface ◽  
Inertial Instability ◽  
Two Factors ◽  
Negative Effect ◽  
Conditional Instability

AbstractWe investigated the influence of upstream terrain on the formation of a cold frontal snowband in Northeast China. We conducted numerical sensitivity experiments that gradually removed the upstream terrain and compared the results with a control experiment. Our results indicate a clear negative effect of upstream terrain on the formation of snowbands, especially over large-scale terrain. By thoroughly examining the ingredients necessary for snowfall (instability, lifting and moisture), we found that the release of mid-level conditional instability, followed by the release of low-level or near surface instabilities (inertial instability, conditional instability or conditional symmetrical instability), contributed to formation of the snowband in both experiments. The lifting required for the release of these instabilities was mainly a result of frontogenetic forcing and upper gravity waves. However, the snowband in the control experiment developed later and was weaker than that in the experiment without upstream terrain. Two factors contributed to this negative topographic effect: (1) the mountain gravity waves over the upstream terrain, which perturbed the frontogenetic circulation by rapidly changing the vertical motion and therefore did not favor the release of instabilities in the absence of persistent ascending motion; and (2) the decrease in the supply of moisture as a result of blocking of the upstream terrain, which changed both the moisture and instability structures leeward of the mountains. A conceptual model is presented that shows the effects of the instabilities and lifting on the development of cold frontal snowbands in downstream mountains.

Does digitalization create or reduce perceived global value?

2018 ◽  
Vol 35 (7) ◽  
pp. 676-687 ◽  
Author(s):  
Ibtissame Abaidi ◽  
Eric Vernette
Keyword(s):  
Undergraduate Students ◽  
Large Scale ◽  
Costs And Benefits ◽  
Content Type ◽  
Complex Effect ◽  
Digital Format ◽  
Two Factors ◽  
Negative Effect ◽  
Cost And Benefit Analysis ◽  
Print Format

PurposeThe internet has made it possible to diffuse totally digitized products on a very large scale. The newspaper business is one of the sectors that has been most affected by this technological revolution. Given such products’ uneven commercial success, an analysis of the literature suggests that these mixed results could be explained by the digitized nature of the product combined with a price judged too high. Both these elements reduce the perceived global value of the digital support compared with the print version on paper. To test this proposition, the authors have constructed an experimental design, manipulating the format (digital newspaper vs. print newspaper) and the price (high vs low). The results show that newspaper digitization significantly reduces perceived global value for the consumer compared with the print format. The authors also show that the perceived intangibility of the product exerts a more complex effect on perceived global value: this effect depends on both the nature of the intangibility (mental vs physical) and the cost and benefit analysis.Design/methodology/approachAn experimental study was conducted with two factors: digitalization (print vs digital format) and price (low vs high). The authors carried out a mixed-factor variance analysis and follow Preacher and Hayes procedure to test the hypothesis. A sample of 387 undergraduate students was interviewed in laboratory.FindingsThe results show that newspaper digitization significantly reduces (i.e. destroys) perceived global value for the consumer (i.e. it destroys value), compared to the print format. The reuslts also show that the perceived intangibility of the product exerts a more complex effect on perceived global value: this effect depends at the same time on the nature of the intangibility (mental vs physical) and the account taken of costs and benefits.Originality/valueOne major result is the fact that digitizing newspaper strongly destroys its perceived global value for the consumer, compared to the physical alternative. To explain this phenomenon, the product’s perceived intangibility had been considered, as well as how this is related to the perceived costs and benefits. It appears that it has an overall direct negative effect on perceived value; therefore, the more a newspaper format is perceived as physically intangible, the more its perceived global value decreases. Results shows that this loss of value can be counteracted in two different ways, through the indirect effects of costs and benefits.

scholarly journals Formulation of technogenic underwater noise problem as a factor of state marine and transport policy

2021 ◽  
Vol 3 (397) ◽  
pp. 115-126
Author(s):  
V. Tarovik ◽  
Keyword(s):  
Large Scale ◽  
Physical Phenomenon ◽  
Transportation Policy ◽  
Research Centre ◽  
Underwater Noise ◽  
Economic Competition ◽  
Two Factors ◽  
Sonar Systems ◽  
Port Infrastructure ◽  
Technogenic Noise

Object and purpose of research. The study addresses the technogenic underwater noise issues with a view to environmental and competitive challenges, as well as the Navy interests. Materials and methods. The issues studied in this investigation are relatively new for the Russian shipbuilding, shipping and marine activities, and the first step to systematic studies should be formulation of a technogenic noise problem as a physical phenomenon, which have to be considered in the state marine and transportation policy. The paper uses results of design studies performed in Krylov State research Centre, as well as information from mass media. The main sources of the technogenic underwater noise are coastal industries and port infrastructure, marine oil & gas structures, transport and ice-breaking vessels. Main results. It is concluded that a special-purpose integrated target program should be formulated and performed, whose result would be systematization of research and design projects aimed at the analysis, regulation and standardization of technogenic underwater noise parameters of various marine technologies. Conclusion. Technogenic underwater noise is directly related to the safety of marine ecosystems. In addition, it is a factor of commercial and large-scale economic competition in the international community. In future the technogenic underwater noise of marine facilities may become an instrument of competition for the opportunity and right to exploit Russian oil & gas deposits, as well as to use Russian Arctic routes. Against the backdrop of these two factors, the Navy interests are obviously to raise the efficiency of fixed and mobile sonar systems in the environment of high technogenic noise produced by civil marine activities.

The Role of Fossil Fuels in a Hydrogen Economy

2021 ◽  
Author(s):  
Hon Chung Lau
Keyword(s):  
Carbon Capture ◽  
Large Scale ◽  
Fossil Fuels ◽  
Carbon Tax ◽  
Developing Economies ◽  
Carbon Capture And Storage ◽  
Energy Transition ◽  
Renewable Energies ◽  
Two Factors ◽  
Final Energy Consumption

Abstract The world of energy is transitioning from one based on fossil-fuels to one based on renewable energies and hydrogen as an energy carrier. At present, only 11% of the world's final energy consumption and less than 1% of industrial hydrogen come from renewable energies. Our analysis shows that this energy transition will take several decades because of two factors. First, renewable energies give more CO2 savings in replacing fossil fuels in the power sector than producing hydrogen for heat generation in the industry sector. Therefore, significant quantities of green hydrogen will not be available until renewable energies have replaced fossil fuels in power generation. This will take at least two decades for advanced economies and twice as long for developing economies. Second, even if blue hydrogen produced by fossil fuels with carbon capture and storage (CCS) is available in large quantities, it is still more expensive than blue fossil fuels which is also decarbonized by CCS. Consequently, fossil fuels and CCS will continue to play a key role in this energy transition. To accelerate this energy transition, governments should introduce a significant carbon tax or carbon credit to incentivize companies to implement large-scale CCS projects. Nations whose governments adopt such policies will go through this energy transition faster and benefit from the associated job creation and economic opportunities.

scholarly journals Incident Causal Factors and the Reasons for Conducting Investigations: A Study of Five Ghanaian Large-Scale Mines

Safety ◽  
2020 ◽  
Vol 6 (1) ◽  
pp. 9 ◽  
Author(s):  
Eric Stemn ◽  
Florence Ntsiful ◽  
Marconi Afenyo Azadah ◽  
Theophilus Joe-Asare
Keyword(s):  
Large Scale ◽  
Mining Industry ◽  
Causal Factor ◽  
Organizational Safety ◽  
Causal Factors ◽  
Incident Investigation ◽  
Double Loop Learning ◽  
Significant Difference ◽  
Two Factors ◽  
Questionnaire Surveys

Background: This research sought to understand the perspective of mineworkers regarding incident investigations, with the objective of identifying incident investigations improvement opportunities. First, through interviews, the research sought to identify the causal factors considered during investigations and the reasons for conducting investigations in the Ghanaian mining industry. Secondly, through questionnaire surveys, the study focused on understanding the extent to which a large sample of mineworkers considered the identified causal factors and investigation reasons relevant and applicable in their mine. Method: Data were collected from 41 participants through interviews and 659 respondents through surveys, and the data were analyzed through thematic, content, and statistical analyses, including descriptive statistics, one-way ANOVA, and correlation analysis. Result: The interviews led to the identification of five and nine categories of incident causal factors and reasons for investigating incidents, respectively. The results suggested a focus on workers’ unsafe acts as the main incident causal factor and identifying the person who caused the incident as one of the major reasons for investigating incidents, as these two factors where the modal choice from both the interviews and survey across all five mines. The results further showed that concerning the accident causal factors and the reasons for investigating incidents, no significant difference was observed between the perspectives of mineworkers involved in investigations and mineworkers with no investigation responsibilities. Conclusion: It can be concluded from the results that talking to ordinary mineworkers does not generate innovative safety responses in this context, as the workers believe whatever they are taught, without critiquing it. Again, the focus on workers’ behavior as an accident causal factor is an indication of single-loop learning in contrast to double-loop learning, and its implication as well as opportunities to strengthen incident investigation focusing on improving organizational safety have been discussed.

Study on Mergers of Large Scale Corporations in Steel Industry Based on the Perspective of Uncertainty of Market Demand

2014 ◽  
Vol 926-930 ◽  
pp. 3974-3977
Author(s):  
Bo Hong Wu ◽  
Xiao Jiang Zhuang ◽  
Xiang Ji
Keyword(s):  
Steel Industry ◽  
Large Scale ◽  
Capacity Constraints ◽  
Market Demand ◽  
Cost Asymmetry ◽  
Duopoly Model ◽  
Two Factors ◽  
The Cost

This article applies Continuous Duopoly Model of HT (1990) to analyze the cost asymmetry of the upstream enterprises as well as the downstream price being subjected to market constraints two factors. After the study of two aspects on market demand deficiency and demand surplus during the mergers of large scale corporation in steel industry, authors conclude that upstream capacity constraints can play a key role in the mergers of large scale corporations in Steel Industry.

scholarly journals Factors affecting warmth comfort and stuffiness in domestic rooms

1947 ◽  
Vol 45 (4) ◽  
pp. 434-442
Author(s):  
K. W. Yarnold
Keyword(s):  
Air Temperature ◽  
Large Scale ◽  
Wave Length ◽  
Field Work ◽  
The Body ◽  
Equivalent Temperature ◽  
Factors Affecting ◽  
Two Factors ◽  
Striking Change ◽  
The Subject

One object of the investigation was to determine the ideal contributions to warmth comfort in small ‘domestic’ rooms of air heating and radiation. It was soon found that in rooms heated by fires, subjects usually complained of cold backs when the equivalent temperature was in the region of 60–65° F., the accepted standard for buildings heated by convection, and preferred equivalent temperatures above 70° F.Since large-scale trials, using many observers, were clearly necessary, the reliability of 5 min. test periods was studied; these short periods were proved reliable so long as the subject had previously been in a comfortable room for an hour or so.It was found necessary, in rooms heated by fires, to treat separately the side of the subject facing the fire and remote from it. The cooler side must be exposed to an equivalent temperature not much less than 65° F., while radiation falling on the warm side is to be regarded as a very desirable, but nonessential, bonus. These conclusions were confirmed by field work in the subjects' own homes.The eupatheoscope and globe thermometer were modified to enable conditions acting on the two sides of the body to be assessed separately.The extent to which radiation acting on the front of the body could compensate for a cold back to produce what was called ‘minimum comfort’ was also studied. It was shown that down to back equivalent temperatures of about 56° F. an increase of 2° in front equivalent temperature will compensate for a fall of 1° in back equivalent temperature, but below 56° F. compensation fails.The physical basis of sensations of stuffiness and freshness were also investigated. Throughout these experiments care was taken to ensure that the subjects were neither too hot nor too cold. In these conditions, only two factors appear to be important. First, the air temperature should be as low as possible. To obtain warmth comfort with a low air temperature some high temperature source of radiation is generally necessary. The peak wave-length of the radiation emitted by the fire is also of great importance, a striking change in the personal sensations occurring, for example, as the wave-length increases from 2 to 3μ. In general, those wavelengths which are absorbed in the outer layers of the skin cause sensations of stuffiness, and those which are not give rise to feelings of freshness. Peaks at 3, 4·1 and 4·7 μ should therefore be avoided in the design of gas and electric fires.

scholarly journals Removal Methods Assessment Through Reduction Algae Count in Uncovered Water Tank

2018 ◽  
Vol 7 (4.20) ◽  
pp. 200
Author(s):  
Nesrin Jassim Al- Mansori ◽  
Saif Al deen ali klakeel
Keyword(s):  
Rotational Speed ◽  
Rotation Speed ◽  
The Other ◽  
Water Tank ◽  
Green Growth ◽  
Algae Removal ◽  
Two Factors ◽  
Time Required ◽  
Biological Methods ◽  
The Cost

The research includes study the effect of three factors (voltage, rotational speed, acidity) with time to remove or reduce the percentage of algae in uncovered water tank; these factors studied combined with each other or individually. the removal percentage of algae increased by increasing the electrical voltage, Best result of removal was obtained when using two factors, change in the voltage (4, 8,12 and 16) vole /cm and speed of rotation (50, 100, 150 and 200) rpm . The rate of removal of algae was 100% at voltage 16 volts with a rotation speed (200) rpm and 40 min.   The values extracted for algae removal showed that the best result was (100%) at (voltage 16 vole/cm and acidity with pH 4) with time 30 min. It can be conclude, the best method to remove or reduction of algae in uncovered tanks was physical one as a compared with the other methods like chemical or biological methods. Therefore, it needs additional requirements unlike physical strategies decrease, the cost and time required to evacuate green growth. 

scholarly journals Suppression of Surface Waviness Error of Fresnel Micro-Structured Mold by Using Non-Integer Rotation Speed Ratio in Parallel Grinding Process

Micromachines ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 652 ◽  
Author(s):  
Yongcheng Pan ◽  
Qingliang Zhao ◽  
Bing Guo ◽  
Bing Chen ◽  
Jinhu Wang
Keyword(s):  
Large Scale ◽  
Rotation Speed ◽  
Simulation Models ◽  
Speed Ratio ◽  
Grinding Process ◽  
Surface Waviness ◽  
Experiment Research ◽  
Grinding Kinematics ◽  
Parallel Grinding ◽  
Proper Wave

Fresnel micro-structured lenses are widely used in the field of modern optoelectronic technology. High-precision Fresnel micro-structured mold is the key technology to achieve its large-scale replication production. Focusing on the surface waviness error of Fresnel micro-structured mold machined by parallel grinding process, this paper conducted theoretical modeling and experiment research. Based on the grinding kinematics theory, the simulation models of the surface waviness topography and the circular waviness profiles of the ground Fresnel micro-structured mold were developed, considering the combined influence of the non-integer rotation speed ratio and other grinding parameters. A series of grinding experiments were carried out to verify the proposed simulation models. The influence of a non-integer rotation speed ratio and a wave-shift value upon the surface waviness error of the ground Fresnel micro-structured molds were analyzed. Both the simulation and experimental results proved that choosing the non-integer rotation speed ratio and a proper wave-shift value could greatly reduce the surface waviness error and improve the surface quality and uniformity.

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