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Consideration of demand rate in OEE

Consideration of demand rate in OEE (overall equipment effetiveness) on equipment with constant process time, It is called lean as it uses less, or the minimum, of everything required to produce a product orperform a service (Hayes & Pisano, 1994). It is therefore the elimination of seven importantwastes is important in Lean environment to ameliorate the effects of variability in supply, processing time or demand (Shah & Ward, 2007). However, it is very difficult to find a concise definition which everyone agrees. Different authors define it distinctively (Wong, Wong & Ali, 2009). The same goes to the implementation of OEE, which is one of the lean tools. Theambiguity of the OEE implementation is especially outstanding during the classification of theelement and acquisition of precise data during the computation of OEE. This could be seenfrom the evaluation of performance ratio in the equipment which carries out process with fixedcycle time. The difficulty faced in this situation including the acquisition and definition of theideal cycle time since it’s preset as per recipe or process parameter, constant from time to timeand unchangeable. This could further contribute to deviation in evaluating the utilization andperformance of a particular production cell (machine). According to Williamson, there is no specific value for so-called “world-class OEE regardless of85 percent OEE which has been cited frequently (2006). This means the action of maximizingand pursuing for high OEE value may not be justifiable. In that, optimum levels of OEE islargely dependent of the capability or capacity of the asset, the business demands, andwhether it is a constraint in the process flow. The idea from the statement is that high level ofproduction rate implied in high OEE (availability), if ignoring the low business demand, willcontribute to expensive inventory handling cost. Besides that, the ideal cycle time is alwaysdifficult to be defined whereas the speed loss, minor stoppage, and idling are hardly to bedifferentiated from the waiting time. (Bamber, Castka, Sharp & Motara, 2003; Kenis, 2006).Besides that, setup and adjustment time which increase accordingly with the product mix inmanufacturing company will adversely affect the OEE value (Mileham, Culley, McIntosh, Gest &Owen, 1997). In other words, mass manufacturing of several product mixes should becompromised due to high-OEE emphasis, of which is illogical from the perspective of business.Regarding to this, there is a need to improve the productivity of a manufacturing organizationwith respect to different market and product mixes (Hilmola, 2005), at the same timeconsidering the customer demand in pursuing high OEE value and defining ideal cycle timeparticularly on machines with fixed and constant process cycle time.The OEE value once being evaluated is just a displayed value and indication of currentutilization of machine only. The story behind the value is seldom tracked out and thecorresponding action in optimizing the machine utilization is not implicit. So, there is a need forinternal flexibility within manufacturing system which will require changes of traditionalorganization methods to manage, measure, and mindset of management and employees onthe role (Sweeney, 1990). Also, the integration of OEE with other lean tools is very poor andthe leaner production system is hard to achieve without the integration of different lean tools.This is very crucial since production floor employees who are not well aligned with a philosophywill exhibit lower levels of desired attitudes and behaviors (Gagnon & Michael, 2003).In order to fix the issue stated above, the paper is structured to start with review of literatureconcerning the OEE contribution and its working mechanism so that the limitation and difficultycould be tracked out in detail. It’s revealed that the traditional definition of OEE doesn’t relatethe utilization of machine with the customer demand. The performance ratio is not applicable …

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Runoff Coefficients for Different Hill Slope Soil Profiles

Hill Slope Soil

The estimation of peak discharge from a catchment Hill Slope Soil due to intense rainfall is a difficult task that may occur in a return period. If cannot be estimated accurately Hill Slope Soil , it may lead to serious problem in hydraulic structure design like bridge, culvert across a river and drainage system. The main parameter which affects the peak flow is runoff coefficient of the catchment which directly depends on the soil type, its slope and land use pattern with vegetation covers. For the purpose, this study was carried out to estimate maximum runoff coefficients for different land profiles and soil types in hill slope model developed in 10 degree with the horizontal to the rainfall simulator rig (Basic Hydrology system-S12) experimentally which can give more reliable value than the real field test method as it is easier than field test especially in hill slope. The soil slope preparation was made of sand, silt and clay separately and the experiments were carried out in a controlled system. The slope prepared represented a small catchment on a plot of 2.02 meter length, 1 meter wide and 0.15 m depth soil plots (at the slope of 10° to the horizontal plane). From the experiment in different soil plots, the rainfall runoff coefficients were observed as 0.428 – 0.53 for sand soil slope, 0.46 – 0.55 for silt soil slope and 0.42 – 0.51 for clay soil slope under uniform rainfall rate of 4 lpm to 13 lpm in each soil slope. Rainfall runoff correlation equation was found with the values of R above 90% in each soil slope. The value observed is within the range of rational value of 0.05 to 0.95 as standard which concluded that the performance of simulator was found good to deal with rational values. And the runoff coefficients for these soil types can be taken within the range obtained to estimate peak discharge in any small catchment area depending on the soil types.

Estimation of the peak discharge due to a heavy rain in a catchment is a difficult task. For a return period, determination of the peak discharge in a catchment is necessary. Discharge is influenced by rainfall (intensity and duration), flow length, contributing area, slope, surface type/roughness, and micro topography/depressions. Accurate peak discharge estimations are important when sizing highway culverts to prevent possible flood damages and to ensure economic design [1]. Peak flow estimates are also required for storm water management plans, reservoir operation and management, flood plain mapping besides most civil structure designs.

The rational method is one of the widely used overland flow design methods to estimate the peak discharge. The rational equation is:

Qpeak=CIAQpeak=CIA(1)

where Qpeak is the peak flow rate (cfs), C is dimensionless coefficient, I is the intensity of rainfall with a time duration equal to the time of concentration (iph) and A is drainage area in acres [1]. The coefficient C is called the runoff coefficient and is the most difficult factor to accurately determine. C must reflect factors such as interception, infiltration, surface detention and antecedent conditions.

The run of coefficient represents the effects of the catchment losses and hence depends on the nature of the surface, surface slope and rainfall intensities. If the surface is homogenous it is easy to consider the value of runoff coefficient but for the non-homogenous catchment it is difficult to select the best value of C and at this case, the catchment area should be divided into distinct subareas having individual coefficient and the runoff should be calculated for each separately and merged in proper time sequence. In complex nonhomogenous catchment area, a weighted equivalent runoff coefficient should be calculated. The main concern in selecting the runoff coefficient values is that these values are chosen based on the personal judgment, which sometimes may be quite vague. Adhikari et al. (2002) carried out studies on runoff coefficient using rational formula for 3 sites of the semi-arid region of India. Long term runoff, rainfall data and stage level records were used in the study. The results show that the estimated “C” values are 40% to 60% less than the “C” values obtained from the standard table. It was found the mean values from 0.091 to 0.42 for different land use pattern micro water shade studied for rational method [2].

Also time of concentration (Tc) is most important hydrological parameter for a catchment at which the peak flow occurs. It is the time at which the raindrop from the farthermost point of a catchment reaches to the outlet. The exact time of concentration must be estimated which depends on the size and shape, slope and soil type over the catchment [3]. It also highly depends on the type of crops in agricultural area and the rapid urbanization with compacted concrete structures [4]. The depression storage (trenches) in land surface also has significant effect on surface runoff and time of concentration, consequently it affects to the runoff coefficient [5]. The contribution of a storm to the ground water also depends on the runoff coefficient of a catchment which varies from 32% to 95% in a watershed [6]. There are various hydraulic models for time of concentrations computation and empirical formulae [7]. The mostly used empirical model for estimation of time of concentration is kirpitch (1940) and given as:

Tc=0.0195L0.77S0.385Tc=0.0195L0.77S−0.385(2)

where, L is the length of catchment and S is the slope of the catchment.

For water management, an engineer must be capable to estimate the peak flood flow in gauged and ungauged river basin which is a difficult task [8]. The rational formula is a very useful equation to estimate it. However, the rational formula is incapable to find out the accurate time of peak flow occurrence. Similarly, the physical process of rainfall-runoff could not be observed and difficult to study in real field especially in hill slope. But the physical process could be studied in the laboratory set up as the catchment is assumed as small prototype giving a small hill slope model [9].

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Waste Bamboo Fiber Addition on Mechanical Properties of Soil

Bamboo Fiber

For soil improvement, a method using plant fiber has been used since ancient times. In recent years, the construction method using plant fiber has attracted attention as a ground improvement technology with less environmental load. In this work, the soil improvement effect using waste bamboo fiber was experimentally examined. The liquid limit and plastic limit of the mixed soil tended to increase with increasing bamboo fiber content and there was no change in the plasticity index of the mixed soil by the difference of bamboo fiber content. As a result from the compaction test and unconfined compression test, it was revealed that mixing of bamboo fiber resulted in a reduction of soil material required for construction and increasing in strength. The maximum compressive stress of the bamboo fiber mixed soil at the mixing ratio of 0%, 1%, 3% and 5% were 115, 108, 130 and 152 kN/m2, respectively. As the soil with fiber showed the lower stiffness and higher strength than that without fiber in the dry region, it can be judged that the addition of fiber brought ductility to the soil. And it was found that the decrease in the stiffness of the specimen due to the increase of water content was suppressed by the addition of the bamboo fiber. From the results of the observation with the digital microscope, it was observed that the two-layer structure consisting of the main relatively thick fibrous structure and the secondary capillary fibrous structure were formed. Thus, it was found that the complex structure of the bamboo fiber is deeply involved in the strength of the mixed soil.

In recent years, the invasion of neglected bamboo forest into Satoyama in Japan has become a more serious problem. When bamboo invades the surrounding fields and forests, the growth of other plants and trees will be inhibited as a result of light shielding by height and occupying the area by making groups. In addition, since the roots of bamboo spread widely in the ground as much as 30 cm depth, it is known that the watershed protection function declines, and landslides are induced if heavy rain falls. Bamboo grows fast and breeds by underground stems. Therefore, just removing the bamboo shoot does not mean that the bamboo itself is removed. Once bamboo invades Satoyama, it is difficult to completely remove them. For the above reasons, while maintaining the bamboo grove which has been excessively propagated, it is also required to establish the effective utilization method of bamboo and to bring the bamboo grove into profitability again.

In the improvement of ground during the construction of structures, the methods using plant fibers have been used for a long time. It is known that the stable improvement of soil material by not only bamboo waste materials but also natural substances has been done for thousands of years. Hejazi et al. [1] summarized the history of stable improvement of soil material by natural substances as follows. They stated that in the Mesopotamian civilization limestone was used as construction material with mixing into weak soil, and in various ancient civilizations straw and hay, etc. were mixed with mud and those were used as a sun-dried brick. They also stated that people were improving the ground soil using familiar plant fibers in the Great Wall of China and Ziggurat of Babylon respectively. Furthermore, the ground improvement by natural fibers such as hemp, jute, coconut and bamboo has been done for more than 5000 years as a traditional construction method.

Various improvements of building materials using the bamboo have been carried out by efforts to eliminate the bamboo groves problem and development of construction method considering the environment in recent years. Several studies showed that the bamboo fiber was the suitable fiber for mixing with the cement material [2] [3] . It is clarified that the improvement effect was much superior to that by other fibers. As a further improvement, various fibers are added into lime-soil to enhance the mechanical properties, and to reduce the vertical and lateral deformation [4] [5] [6] . Nishida et al. [7] investigated the improvement effect due to the high water absorption by adding the bamboo waste material with the cementitious solidifying material to the bottom sediment with high water content. As a result, it was clarified that the bottom sediment with high water content can be improved to the transportable strength by adding the bamboo waste material. It was also revealed that the improvement effect was larger for the water absorbing material with higher water absorption ratio. Yamashita et al. [8] studied the strength and cracking characteristics of the building wall mixed with the bamboo as the reinforcing material. As a result, it was revealed that the unconfined compressive strength of the wall clay mixed with the bamboo was greater than that of the conventional wall clay mixed with the straw. In addition, it was revealed that the cracked area ratio decreased by increasing the added amount of the reinforcing material regardless of that type. In particular, it was reported that the effect of suppressing cracks was remarkable in the bamboo fiber with long fiber length. Sako et al. [9] examined the availability of the bamboo chips to prevent the erosion of the promenade in the historic site. As a result, it was revealed that the specimens mixed with the bamboo chips had high erosion resistance and increased the unconfined compression strength. Otsubo et al. [10] used the bamboo fiber as the base material for the sprayer in the greening plant of the slope, and investigated the erosion preventing the effect of the base material itself. They showed that utilizing the bamboo fiber resulted in less erosion than the conventional methods. Sato et al. [11] have extensively investigated the improvement of soft clay by incorporating bamboo chips and flakes that have high water absorption characteristic of bamboo material. Brahmachary and Rokonuzzaman [12] conducted the number of soaked and unsoaked CBR value tests for ordinary soil and soil mixed with different quantity of bamboo fiber, and concluded that both unsoaked and soaked California Bearing Ratio (CBR) value of soil increases due to the addition of bamboo fiber. Devi and Jempen [13] investigated the shear strength behavior of a bamboo fiber reinforced soil. They showed an increase in the shear strength parameters of the soil with an increase in the percentage of fiber up to an optimum amount. Ismanti and Yasufuku [14] presented the utilization of natural and environmental-friendly material, bamboo chips, mixed with a small amount of cement content in soil improvement. Thus, fiber-soil has been attracting attention in geotechnical engineering [15] [16] .

As described above, various studies on soil improvement using bamboo waste materials have been conducted all over the world. From the results of the past research, it can be judged that the ground improvement by the bamboo waste material can be applied to the embankment work at general civil engineering sites and the levee embankment at the agricultural field. Generally, relatively rough bamboo chips and flakes are the common fiber conditions used in those research, and the research as for the application of fine bamboo powder is not much. In this paper, focusing on the relatively fine bamboo powder, the physical and mechanical characteristics of the bamboo fiber mixed soil were experimentally investigated and the effect of the improvement was clarified.

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The Production of Pineapple Leaf Fibers Reinforced Normal Strength Concrete

 

Pineapple Leaf Fibers The present work tried to develop suitable proportions for the production of Pineapple Leaf Fibers (PALF) reinforced Normal Strength Concrete (NSC), an experimental analysis with a mix ratio of 1:1.84:3.27 for cement: fine aggregates: coarse aggregates with constant water to cement ratio of 0.54. The Pineapple Leaf Fibers total volume per mixing batch was calculated of 9 cubes + 9 cylinders + 3 beams in order to know the number of materials to be used in casting per batch, and the PALF percentage was taken based on cement weight whereby it starts from the lowest to the maximum as follow 0%, 0.2%, 0.4%, 0.6%, 0.8%, and 1%. The tests that were done on fresh concrete were compacting factors and workability using the slump test which was carried out on each fresh mix of concrete. The results showed that PALF can be used to improve the Tensile and Flexural properties of Normal Strength Concrete.

The construction industry is one of rapidly growing industries across the world. In this industry, concrete plays an inherent role and is the most widely used manmade construction material. Concrete will continue to be the leading construction material all over the world due to its versatile advantageous properties such as good compressive strength, and high mould ability, plastic and malleable when fresh and durable, impermeable and fire resistant when hardened [1] [2]. Concrete is therefore used for advanced applications, design and construction techniques such as building houses, bridges, dams, pavements, stadiums, retaining structures, airports and skyscrapers. However, NSC has some undesirable properties like being weak in tension, brittleness, less resistance to cracking, low impact resistance and heavy weight, hence there is a need to improve the concrete properties [3] [4]. Pineapple Leaf Fibers (PALF) are more compatible natural fiber resource and constitutes a good chemical composition [5]. PALF are a vital natural fiber, which have a high specific strength, rigidity, flexural and torsional rigidity than other fibers; seen all these advantages of PALF and since no one has developed suitable proportion of production of PALF reinforced on NSC it is time to try such fiber. Natural fibers have the advantages of low density, low cost, and biodegradability. When concrete cracks, the randomly oriented fibers start functioning, arrest crack formation and propagation, and thus improve strength and ductility. Natural fibres from pineapple leaves are a good option to study because of their high tensile strength and high cellulose content [6]. The use of PALF reinforcement in construction materials can enhance structural strength and toughness, and this can reduce cracking and shrinkage [7]. Hence this study was made to develop a suitable proportion of production of PALF on properties of NSC.

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Prosedur Algoritma

Prosedur Algoritma

Algoritma adalah prosedur langkah demi langkah, yang mendefinisikan sekumpulan instruksi yang akan dieksekusi dalam urutan tertentu untuk mendapatkan keluaran yang diinginkan. Algoritma umumnya dibuat terlepas dari bahasa yang mendasarinya, yaitu algoritma dapat diimplementasikan di lebih dari satu bahasa pemrograman.

Dari sudut pandang struktur data, berikut adalah beberapa kategori penting dari algoritma –

Search – Algoritma untuk mencari item dalam struktur data.

Sortir – Algoritma untuk mengurutkan item dalam urutan tertentu.

Sisipkan – Algoritma untuk memasukkan item ke dalam struktur data.

Perbarui – Algoritma untuk memperbarui item yang ada dalam struktur data.

Hapus – Algoritma untuk menghapus item yang ada dari struktur data.

Karakteristik Algoritma
Tidak semua prosedur bisa disebut algoritma. Algoritma harus memiliki karakteristik berikut –

Tidak ambigu – Algoritma harus jelas dan tidak ambigu. Setiap langkah (atau fase), dan masukan / keluarannya harus jelas dan hanya mengarah pada satu makna.

Input – Algoritma harus memiliki 0 atau lebih input yang didefinisikan dengan baik.

Keluaran – Algoritma harus memiliki 1 atau lebih keluaran yang terdefinisi dengan baik, dan harus cocok dengan keluaran yang diinginkan.

Keterbatasan – Algoritma harus berhenti setelah sejumlah langkah yang terbatas.

Kelayakan – Harus layak dengan sumber daya yang tersedia.

Independen – Algoritma harus memiliki petunjuk langkah demi langkah, yang harus independen dari kode pemrograman apa pun.

Bagaimana Cara Menulis Algoritma?
Tidak ada standar yang didefinisikan dengan baik untuk penulisan algoritma. Sebaliknya, ini tergantung pada masalah dan sumber daya. Algoritma tidak pernah ditulis untuk mendukung kode pemrograman tertentu.

Seperti yang kita ketahui bahwa semua bahasa pemrograman berbagi konstruksi kode dasar seperti loop (do, for, while), flow-control (if-else), dll. Konstruksi umum ini dapat digunakan untuk menulis algoritma.

Kami menulis algoritma secara selangkah demi selangkah, tetapi tidak selalu demikian. Penulisan algoritma adalah sebuah proses dan dijalankan setelah domain masalah didefinisikan dengan baik. Artinya, kita harus mengetahui domain masalahnya, untuk itu kita sedang merancang solusinya.

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