PROSES PEMBUATAN KONSTRUKSI PADA ALAT ROLLER BENDING

Tugas Akhir ini membahas tentang pembuatan konstruksi pada alat roller bending. Bertujuan untuk menghasilkan komponen seperti Roller Home, Roller Home stand, base, steering wheel home 1 dan steering wheel home 2 pada alat roller bending, serta untuk memperoleh gambaran nyata tentang waktu dan biaya yang dibutuhkan untuk pembuatan komponen tersebut. Pembuatan komponen ini menggunakan material utama yang digunakan adalah ST60. Proses pemesinan untuk pembuatan komponen-komponen pada Konstruksi alat roller bending meliputi: 1) proses grinding; 2) proses drilling; 3) proses welding. Secara teoritis total waktu dan biaya produksi yang dibutuhkan adalah 4,93 jam dan Rp. 809.000. dan secara Real waktu dan biaya produksinya 5,16 jam dan Rp. 821.000.;--- This final project discusses the construction of roller bending tool. Aims to produce components such as Roller Home, Roller Home booth, base, steering wheel home 1 and steering wheel home 2 on the roller bending tool, as well as to get a real idea of the time and cost required for the manufacture of these components. Making this component using the main material used is ST60. The machining process for the manufacture of components on the roller bending tool Construction includes: 1) grinding process; 2) drilling process; 3) welding process. Theoretically the total time and production cost required is 4.93 hours and Rp. 809,000. and Real time and production costs 5.16 hours and Rp. 821,000

The effects of seagrass patch size and energy regime on growth of a suspension-feeding bivalve

An investigation of how the presence of seagrass and seagrass patch size in high- and low-energy environments affected growth of an infaunal bivalve (hard clam, Mercenaria mercenaria) was carried out. Two general size classes of clams were used, mean length ca. 40.0 mm (41.9 mm) and mean length ca. 20.0 mm (22.3 mm and 19.0 mm), to see if growth responses were the same for large- and small-sized clams. Seagrass density, length and species composition as well as sediment characteristics were measured at high- and low-energy sites to determine if changes in seagrass and/or sediment dynamics could explain observed growth patterns. The incidence of siphon cropping was also evaluated as a potential influence on clam growth. Large clams grew faster inside than outside vegetation at both high- and low-energy sites. Within the vegetation, growth of large clams was faster in medium-sized patches of seagrass (2–3 m across) than in small patches (1 m across) and was intermediate in large patches (\u3e 4–5 m across). There was no apparent correlation between seagrass shoot density, blade length, or species composition and growth of clams in patches of different size. Growth of small clams (22.3 mm) within seagrass was independent of the two seagrass patch sizes tested (large vs. small), but did vary among sites. Growth of clams was not correlated with differences in shoot density, blade length or species composition among sites. Growth of small clams (19.0 mm) also varied with energy regime and with presence/absence of vegetation. Small clams grew significantly more within seagrass under both high- and low-energy conditions, but the effect was more pronounced at high-energy sites than at low. Seagrass shoot density, blade length, and species composition did not vary between high and low energy regimes, but did vary among sites from the beginning to the end of the experiment. Long-term averages of sediment stability based on grain size characteristics suggest that the baffling effect of seagrass varies greatly with energy regime. Vegetated sediments at high-energy sites contained significantly more fine material than the unvegetated sediments while there was no difference in the fine fraction between vegetated and unvegetated sediments at low-energy sites. The difference in sediment stability between seagrass cover under high- and low-energy conditions may contribute to the magnitude of the difference in the growth response of small clams to the presence of vegetation at exposed and protected sites. Other factors also contributed to the increased growth of clams in seagrass beds at the protected sites where grain size analysis suggests similar sedimentary dynamics both within and outside of the vegetation. Mean adjusted siphon weights, however, for both large and small clams were independent of seagrass cover and energy regime implying that siphon nipping differences did not influence growth patterns of clams. Based on this study, and previous investigations, the effect of seagrass cover on growth of clams appears to be the result of a complex interaction among food supply, predation disturbance, and sediment stability with the relative importance of these processes varying with size of the clam, hydrographic regime, and local site differences

Potential and Challenges for Private Sector to Lead Warung Digitalization in Indonesia

The purpose of this study is to understand the potential and challenges for the private sector to lead the process of warung digitalization to improve their business. MSMEs such as warung in Indonesia have been a tool for income generation for many people. Though the number of warungs that have leveled up is still minimum—most of their business are stagnant. This has resulted in their constant welfare situation. The approach used in this study is qualitative with the literature review method. This study finds that there is potential for the private sector to be the trailblazer in the digitalization process because of their characteristics and traits, the other actors’ situation, and the profit to be gained. Though, there are some challenges to be addressed, such as the lack of supporting infrastructure, minimal regulatory framework, and the need to train the warung owner

Potential and Challenges for Private Sector to Lead Warung Digitalization in Indonesia

The purpose of this study is to understand the potential and challenges for the private sector to lead the process of warung digitalization to improve their business. MSMEs such as warung in Indonesia have been a tool for income generation for many people. Though the number of warungs that have leveled up is still minimum—most of their business are stagnant. This has resulted in their constant welfare situation. The approach used in this study is qualitative with the literature review method. This study finds that there is potential for the private sector to be the trailblazer in the digitalization process because of their characteristics and traits, the other actors’ situation, and the profit to be gained. Though, there are some challenges to be addressed, such as the lack of supporting infrastructure, minimal regulatory framework, and the need to train the warung owner

PENGARUH PEMBELAJARAN MODIFIKASI PERMAINAN SEPAK BOLA TERHADAP TINGKAT KEGEMBIRAAN PADA SISWA SMP NEGERI 2 GEDANGAN

Abstrak Pada kegiatan belajar mengajar pendidikan jasmani terdapat adanya pembelajaran sepak bola, dan pada saat pembelajaran adanya penyajian yang kurang menarik menyebabkannya menurunnya minat pada siswa-siswi terhadap pembelajaran. Di SMP Negeri 2 Gedangan melihat bola yang terbatas dengan melihat siswa-siswinya yang cukup banyak, maka dari itu sarana yang digunakan untuk pembelajaran harus aman agar memperlancar pembelajaran, selain itu dengan melihat siswa-siswi nya yang kurang senang terhadap pembelajaran sepak bola karena sulit mengontrol bola. Tujuan pada penelitian ini adalah mengetahui besarnya pengaruh pembelajaran modifikasi permainan sepak bola terhadap tingkat kegembiraan siswa-siswi pada pembelajaran sepak bola. Penelitian ini menggunakan jenis penelitian eksperimen dan memakai randomized control group pretest-posttest design. Populasi pada penelitian ini yaitu seluruh siswa kelas VIII SMP Negeri 2 Gedangan. Jumlah sampel pada penelitian ini yaitu 68 siswa yang dibagi menjadi dua kelompok (kontrol dan eksperimen) dan ditentukan dengan teknik cluster random sampling. Instrumen yang digunakan adalah angket kegembiraan siswa. Hasil penelitian pada penerapan modifikasi permainan sepakbola memberikan peningkatan yang positif dengan nilai signifikasi sebesar 0,000 < 0,05 terhadap kegembiraan siswa SMP Negeri 2 Gedangan dalam mengikuti pembelajaran PJOK, yakni dengan menghasilkan peningkatan 2,05%. Kata Kunci: modifikasi; sepak bola; kegembiraan   Abstract In physical education teaching and learning activities there is soccer learning, and at the time of learning, there is an unattractive presentation which causes a decrease in student interest in learning. At Junior High School 2 Gedangan seeing a limited ball by looking at the number of students, therefore the means used for learning must be safe in order to facilitate learning, in addition to seeing the students who are not happy with learning soccer because it is difficult to control ball. The purpose of this study was to determine the influence of learning modification of the soccer game on the level of joy of students in learning football. This study used an experimental research type and used a randomized control group pretest-posttest design. The population in this study were all students of class VIII Junior High School 2 Gedangan. The number of samples in this study were 68 students who were divided into two groups (control and experiment) and were determined by cluster random sampling technique. The instrument used was a student joy questionnaire. The results of the research on the application of modification of the game of football gave a positive increase with a significance value of 0.000 <0.05 on the joy of students of Junior High School 2 Gedangan in participating in PJOK learning, namely by producing an increase of 2.05%. Keywords: modification; soccer; enjoyment &nbsp

Replicated shape variation between simple and complex habitats in two estuarine fishes

A replicated pattern of habitat-associated morphology among different lineages may represent adaptive convergence. Deviation from the replicated (shared) pattern of diversification reflects unique (e.g. species specific) effects resulting from site- or species-specific selection, intrinsic factors (e.g. G matrix differences) or chance historical events (e.g. genetic drift). For two distantly-related estuarine fishes [Lagodon rhomboides (Sparidae; Linnaeus) and Leiostomus xanthurus (Sciaenidae; Lacepede)], we examined shared and unique instances of body shape variation between seagrass (complex) and sand (simple) microhabitats at four sites. We found extensive shape variation between microhabitats for both species. As a shared response, both species from sand had subterminal snouts and long caudal peduncles, whereas those from seagrass had terminal snouts and deep bodies. Unique responses involved a greater difference in Lagodon rhomboides head shape between microhabitats compared to L. xanthurus. Patterns of shape variation fit ecomorphological predictions for foraging in the respective microhabitats (simple versus complex) because deep bodies are expected for fish that must negotiate complex habitats and subterminal snouts facilitate benthic foraging common in barren habitats. Parallel differentiation between microhabitats simultaneously suggests that individuals of each species use a particular microhabitat within estuaries for development and the differentiation in shape represents adaptive convergence. Spatial variation in the magnitude of shape differences between microhabitats was an unexpected finding and suggests that phenotypic variation operates at multiple scales within estuaries

Context-dependent community facilitation in seagrass meadows along a hydrodynamic stress gradient

Foundation species host diverse associated communities by ameliorating environmental stress. The strength of this facilitative effect can be highly dependent on the underlying biotic and abiotic context. We investigated community level patterns of macrofauna associated with and adjacent to the marine foundation species eelgrass (Zostera marina) along a hydrodynamic stress gradient. We could demonstrate that the relative importance of this foundation species for its infaunal community increases with environmental variables associated with increasing hydrodynamic stress (depth, sand ripples formation, sediment grain size and organic content). Faunal assemblages in proximity to the Zostera patch edges, however, showed no (infauna) or negative (epifauna) response to hydrodynamic stress. Our study highlights that the facilitative outcome of a foundation species is conditional to the faunal assemblage in question and can be highly variable even between positions within the habitat.Peer reviewe

A Meta-Analysis of Seaweed Impacts on Seagrasses: Generalities and Knowledge Gaps

Seagrasses are important habitat-formers and ecosystem engineers that are under threat from bloom-forming seaweeds. These seaweeds have been suggested to outcompete the seagrasses, particularly when facilitated by eutrophication, causing regime shifts where green meadows and clear waters are replaced with unstable sediments, turbid waters, hypoxia, and poor habitat conditions for fishes and invertebrates. Understanding the situations under which seaweeds impact seagrasses on local patch scales can help proactive management and prevent losses at greater scales. Here, we provide a quantitative review of available published manipulative experiments (all conducted at the patch-scale), to test which attributes of seaweeds and seagrasses (e.g., their abundances, sizes, morphology, taxonomy, attachment type, or origin) influence impacts. Weighted and unweighted meta-analyses (Hedges d metric) of 59 experiments showed generally high variability in attribute-impact relationships. Our main significant findings were that (a) abundant seaweeds had stronger negative impacts on seagrasses than sparse seaweeds, (b) unattached and epiphytic seaweeds had stronger impacts than ‘rooted’ seaweeds, and (c) small seagrass species were more susceptible than larger species. Findings (a) and (c) were rather intuitive. It was more surprising that ‘rooted’ seaweeds had comparatively small impacts, particularly given that this category included the infamous invasive Caulerpa species. This result may reflect that seaweed biomass and/or shading and metabolic by-products like anoxia and sulphides could be lower for rooted seaweeds. In conclusion, our results represent simple and robust first-order generalities about seaweed impacts on seagrasses. This review also documented a limited number of primary studies. We therefore identified major knowledge gaps that need to be addressed before general predictive models on seaweed-seagrass interactions can be build, in order to effectively protect seagrass habitats from detrimental competition from seaweeds

Effects of habitat modification in mangroves on the structure of mollusc and crab assemblages

The abundance and species richness of mollusc and crab assemblages were examined in a subtropical mangrove forest in Moreton Bay, Queensland, Australia, which has been disturbed and damaged by the construction of a wooden boardwalk and a path. Sections of the forest immediately adjacent to the boardwalk and path were compared with reference areas to determine whether changes to the small-scale structural complexity within the forest affected the benthic fauna. The disturbed area was characterised by having 65-80% fewer pneumatophores, significantly fewer species and individuals of molluscs, but significantly more species and individuals of crabs than the reference areas. The abundance of mangrove pneumatophores and the attached epiphytic algae were manipulated at two sites to determine whether observed differences in these features could account for the differences in the assemblage of molluscs in the disturbed area of the forest compared with reference areas. Five experimental treatments were used: undisturbed controls, pneumatophore removals (abundance reduced by ca. 65%), epiphytic algal removals (algae removed from ca. 65% of pneumatophores), pneumatophore disturbance controls and algal disturbance controls. The experimental reduction of the abundance of mangrove pneumatophores and the associated epiphytic algae led to significant declines (by as much as 83%) in the number of molluscs utilising the substratum in the modified plots. There was no significant difference in the abundance of molluscs in the pneumatophore and algal removal plots suggesting any effect was primarily related to removal of the epiphytic algae from the surface of the pneumatophores. The responses by the biota to the changes in the physical environment demonstrate that even relatively small-scale modifications to the physical structure of subtropical mangrove forests can lead to significant effects on the diversity and abundance of macrobenthic organisms in these habitats. Such modifications have the potential to cause cascading effects at higher trophic levels with a deterioration in the value of these habitats as nursery and feeding grounds. Future efforts at conservation of these estuarine environments must focus on the prevention or reduction of modifications to the physical structure and integrity of the system, rather than just on the prevention of loss of entire patches of habitat. (C) 2000 Elsevier Science B.V. All rights reserved

Movements of marine fish and decapod crustaceans: Process, theory and application

Many marine species have a multi-phase ontogeny, with each phase usually associated with a spatially and temporally discrete set of movements. For many fish and decapod crustaceans that live inshore, a tri-phasic life cycle is widespread, involving: (1) the movement of planktonic eggs and larvae to nursery areas; (2) a range of routine shelter and foraging movements that maintain a home range; and (3) spawning migrations away from the home range to close the life cycle. Additional complexity is found in migrations that are not for the purpose of spawning and movements that result in a relocation of the home range of an individual that cannot be defined as an ontogenetic shift. Tracking and tagging studies confirm that life cycle movements occur across a wide range of spatial and temporal scales. This dynamic multi-scale complexity presents a significant problem in selecting appropriate scales for studying highly mobile marine animals. We address this problem by first comprehensively reviewing the movement patterns of fish and decapod crustaceans that use inshore areas and present a synthesis of life cycle strategies, together with five categories of movement. We then examine the scale-related limitations of traditional approaches to studies of animal-environment relationships. We demonstrate that studies of marine animals have rarely been undertaken at scales appropriate to the way animals use their environment and argue that future studies must incorporate animal movement into the design of sampling strategies. A major limitation of many studies is that they have focused on: (1) a single scale for animals that respond to their environment at multiple scales or (2) a single habitat type for animals that use multiple habitat types. We develop a hierarchical conceptual framework that deals with the problem of scale and environmental heterogeneity and we offer a new definition of 'habitat' from an organism-based perspective. To demonstrate that the conceptual framework can be applied, we explore the range of tools that are currently available for both measuring animal movement patterns and for mapping and quantifying marine environments at multiple scales. The application of a hierarchical approach, together with the coordinated integration of spatial technologies offers an unprecedented opportunity for researchers to tackle a range of animal-environment questions for highly mobile marine animals. Without scale-explicit information on animal movements many marine conservation and resource management strategies are less likely to achieve their primary objectives