7,851 research outputs found

    Pengaruh Penambahan Admixture Terhadap Karakteristik Self Compacting Concrete (Scc)

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    Penelitian ini adalah eksperimen laboratorium yang sifatnya pengenalan terhadap materi SCC.SCC atau Self Compacting Concrete adalah sebuah inovasi dalam teknologi konstruksi betondewasa ini yang menggunakan bahan tambah (admixture) untuk menghasilkan beton berkinerjatinggi. Pada penelitian ini ingin diketahui pengaruh penambahan admixture kimiaSuperplasticizer “Mighty 150 S” dan Retarder “Conplast Dessue Possolit” terhadap karakteristikSCC. Superplasticizer diberikan dalam 3 variasi kadar (1,5%, 2,0%, 2,5%) dengan mengurangikadar air campuran. Metode pengujian SCC dengan Slump-Cone Test pada kondisi segar dantes kuat tekan pada umur 3, 7, dan 28 hari. Hasil penelitian menunjukkan keadaan selfcompactibilitySCC tercapai pada semua kadar Superplasticizer yang diberikan. Tingkatkelecakan aliran (workabilitas) SCC meningkat sesuai penambahan kadar Superplasticizer, dansebaliknya, kekuatan tekan SCC menurun sesuai penambahan kadar Superplasticizer. Kondisioptimal SCC tercapai pada kadar 1,5% Superplasticize

    Il fenomeno del food waste: gli sprechi alimentari da problema a risorse

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    Il tema degli sprechi alimentari rappresenta un problema globale nonché una preoccupazione centrale del nostro secolo. Negli ultimi anni, il fenomeno ha assunto un’importanza crescente all’interno del dibattito scientifico e delle iniziative della società civile, fino ad essere richiamato nei documenti programmatici dell’UE e delle principali organizzazioni internazionali (FAO, UNEP, USDA, G20). Tuttavia, non esiste ancora una definizione univoca di “spreco alimentare”, così come non esistono metodologie uniformi per calcolarlo; ma, gli studi concordano che il cibo è sprecato ad ogni stadio della filiera alimentare. Si stima che annualmente nel mondo gli sprechi alimentari ammontano a circa 1.3 miliardi di tonnellate (un terzo della produzione totale di cibo destinato al consumo umano). Le cause sono molteplici e si differenziano in base al livello di sviluppo economico raggiunto (Paesi industrializzati o in via di sviluppo) e in base alla particolare struttura della filiera agroalimentare (es. standard dimensionali ed estetici, norme sulla qualità dei prodotti, surplus produttivi o fattori economici). Nel panorama europeo, i Paesi che hanno già avviato azioni e programmi volti a comprendere e contrastare il fenomeno sono molti; ma solo Francia e Italia, nel 2016, hanno adottato una legislazione nazionale in materia. Gli sprechi alimentari generano impatti negativi ambientali ed economici, ma a rendere ancora più allarmante il fenomeno è la questione sociale. Infatti, a fronte di un miliardo circa di persone nel mondo che, allo stato attuale sono sottoalimentate, gli sprechi alimentari appaiono quanto mai inaccettabili. Per stimare l’impatto ambientale di un alimento sprecato è necessario considerare il suo intero ciclo di vita utilizzando indicatori specifici quali il carbon footprint, l’ecological footprint o il water footprint; mentre per quanto riguarda l’impatto economico degli sprechi, esso include la quantificazione delle esternalità negative oltre il costo o il prezzo dei prodotti gettati via. Viste le dimensioni assunte dal fenomeno e soprattutto dalla portata dei suoi impatti, gli sprechi alimentari si allontanano di molto da quelli che sono gli obiettivi di sostenibilità da intraprendere a livello mondiale. Pertanto, la promozione di iniziative di sensibilizzazione e di recupero degli sprechi (es. attraverso il recupero delle eccedenze produttive a fini solidali o per la produzione di bioenergie), oltre all’applicazione di un quadro legislativo, dovrebbe far crescere la consapevolezza di consumatori, produttori, istituzioni e politica che in un mondo in crisi economica, ambientale e sociale, lo spreco è un fenomeno totalmente insostenibile, e non è più consentito. La sostenibilità non può più essere considerata un mero concetto teorico, ma è necessario ripensare i modelli di produzione e di consumo, rivedere comportamenti e stili di vita, per intraprendere un percorso mirato verso una società compatibile con i bisogni delle attuali e delle future generazioni. In tale contesto, la Commissione europea ha presentato un pacchetto per sostenere la transizione dell’UE verso un’economia circolare, nel quale la prevenzione e la minimizzazione degli sprechi alimentari sono parte integrante.Food waste is a global issue and a central concern of our century, it is a significant phenomenon that is currently at the heart of academic debates, civil society initiatives, and political agendas (FAO, UNEP, USDA, G20). However, there is not any standardized definition of “food waste” or any homogeneous and comparable data, but all studies agree that food is wasted at every stage of the food supply chain. Annual global food waste is estimated to be about 1.3 billion tons (a third of the total food production intended for human consumption). There are many causes of waste, differentiated according to the State (industrialized or developing countries) and the various stages of the food supply chain (e.g. due to sizing and esthetic standards, product quality regulations, production surplus or economic factors). Many EU Member States have already launched actions and programmers to promote waste reduction; but only France and Italy, in 2016, have adopted a national regulation to minimize the phenomenon. Food waste have negative environmental and economic impacts and their existence raises serious questions from a social point of view. In fact, given the problem of malnutrition that is afflicting around one billion people worldwide, the food waste appears extremely unacceptable. In order to estimate the environmental impact of a wasted food, it is necessary to consider its entire life cycle using the indicators, such as carbon footprint, ecological footprint, water footprint. The economic impact of wasted food includes calculating the negative externalities, besides the cost or the price of the products thrown away. Given the scale reached by the food waste phenomenon, and above all the scope of its impacts, the food waste deviate very far from those that are the sustainability goals to be taken globally. Therefore, the promotion of awareness initiatives and waste recovery (e.g. by distribution of the productive surplus to solidarity aims or to produce bioenergy), the application of a regulatory framework, should raise consumer, producer, institution and policy awareness in a world in economic, environmental and social crisis where the waste is no longer allowed. Sustainability can no longer be considered a theoretical concept, but is necessary a rethinking of the conventional models of production and consumption, the behaviors and lifestyles, to undertake a focused path towards a society compatible with the needs of the present and the future generations. In this context, European Commission put forward to support the EU’s transition to a circular economy, where food waste prevention and minimization are an integral part

    Evaluasi Pengendalian Intern terhadap Sistem Akuntansi Pembelian dan Persediaan Bahan Baku pada PT Fuyindo Multi Perdana

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    Internal control is essential for the operational activities of a company. The author conducted research for internal control of accounting systems and inventory purchases of raw materials. Internal controls for purchasing and inventory of raw materials is essential if companies want to produce a superior product. In this study researchers prepare the field research method by observation and literature study by studying the theories associated with the purchase and supply of raw materials. The results obtained show the important things that can be controlled by the company for operating companies to run well and the management can give a decision based on the reports of evaluation results, it can be suggested that companies should do in the internal control system purchase accounting and inventory of raw materials

    Scattering by flexural phonons in suspended graphene under back gate induced strain

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    We have studied electron scattering by out-of-plane (flexural) phonon modes in doped suspended graphene and its effect on charge transport. In the free-standing case (absence of strain) the flexural branch shows a quadratic dispersion relation, which becomes linear at long wavelength when the sample is under tension due to the rotation symmetry breaking. In the non-strained case, scattering by flexural phonons is the main limitation to electron mobility. This picture changes drastically when strains above uˉ=10−4n(1012 cm−2)\bar{u}=10^{-4} n(10^{12}\,\text{cm}^{-2}) are considered. Here we study in particular the case of back gate induced strain, and apply our theoretical findings to recent experiments in suspended graphene.Comment: 4 pages, 3 figures, published versio

    Aplikasi Pemasaran Berbasis Web PT XYZ

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    Marketing plays an important role in determining the success of a company's sales. Marketing of goods or services over the Internet opens an opportunity for a company to expand the business into new markets, and compete with other businesses in the same field. It is because the internet offers wider selection of good products, service products, and prices. Thus, customers can be sure in choosing and buying of goods and services. For that e-marketing is introduced as an marketing strategy that integrates internet and marketing. A study was conducted to develop e-marketing application for PT XYZ as a company that produces and sells men's apparel and accessories. The methodology used in developing the e-marketing application is library research, field research, and a seven-stage approach to build e-marketing. The e-marketing strategy developed is expected to expand market share and increase sales. Additionally, it is expected to be a powerful strategy to build relationships with customers, providing information of both company and its products

    BRIQUETTES PRODUCTION FROM LIGNOCELLULOSIC WASTE FOR ENERGY PURPOSES AS AN ALTERNATIVE FUEL

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    The briquetting process was developed seeking to reuse the waste generated both in forestry production and in industrial processes. The compression of lignocellulosic waste concentrates the available energy in terms of volume and facilitates the handling and storage of these materials. The present work aims to verify the influence on the quality of briquettes of different compositions between the residues of coffee grounds, pine sawdust and cambará sawdust by evaluating the physical, chemical and mechanical characteristics of the briquettes generated from the compaction of these waste. For this, several tests were carried out with the briquettes, analyzing the properties of particle size, resistance to diametrical compression, moisture and ash for each composition of the briquette. The briquettes were produced on a 12-tonne hydraulic press. The waste used showed a high concentration of fine particles, with pine sawdust being 50.5% of particles with a diameter of 0.425mm. Coffee beans have moisture content above 50%, positively impacting the ash content and negatively impacting briquetting and tensile strength by diametral compression. In the production of briquettes, material with up to 60% addition of coffee grounds was obtained. The compression tests showed good results for the treatments, highlighting the treatments with a high concentration of pine. It is also concluded that the coffee grounds can be used in the production of briquettes with sawdust, however, it is suggested for future articles, the correction of moisture in the briquettes for better compaction

    Impact of additives and fillers on space charge behavior of polyethylene insulation: investigation and modeling

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    Diagnostic measurements on electrically insulating materials are a compulsory step to assure an acceptable service life of the electrical equipment. In particular, this paper focuses on the consequences of the implementation of several concentrations of antioxidants (Irganox® 1076 and Irganox® PSS02) inside Si-XLPE matrices. Thermally Stimulated Depolarization Current (TSDC) measurements were carried out on pure and filled samples to obtain information about the space charge behavior and trap distribution of the specimens. Postprocessing based on Randal-Wilkins model highlighted additive impact on Si-XLPE properties. Similar trap depth and different trap density values were found in samples with different concentrations of the same additive, suggesting a close correlation between the energy levels of localized states and the used antioxidants

    Development of a Control-Oriented Ignition Delay Model for GCI Combustion

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    Increasingly stringent pollutant emission limits and CO2 reduction policies are forcing the automotive industry toward cleaner and decarbonized mobility. The goal is to achieve carbon neutrality within 2050 and limit global warming to 2 degrees C (possibly 1.5 degrees C) with respect to pre-industrial levels as stated in both the European Green Deal and the Paris Agreement and further reiterated at the COP26. With the aim of simultaneously reducing both pollutants and CO2 emissions, a large amount of research is currently carried out on low-temperature highly efficient combustions (LTC). Among these advanced combustions, one of the most promising is Gasoline Compression Ignition (GCI), based on the spontaneous ignition of a gasoline-like fuel. Nevertheless, despite GCI proving to be effective in reducing both pollutants and CO2 emissions, GCI combustion controllability represents the main challenge that hinders the diffusion of this methodology for transportation. Several works in the literature demonstrated that to properly control GCI combustion, a multiple injections strategy is needed. The rise of pressure and temperature generated by the spontaneous ignition of small amounts of early-injected fuel reduces the ignition delay of the following main injection, responsible for the torque production of the engine. Since the combustion of the pre-injections is chemically driven, the ignition delay might be strongly affected by a slight variation in the engine control parameters and, consequently, lead to misfire or knocking. The goal of this work was to develop a control-oriented ignition delay model suitable to improve the GCI combustion stability through the proper management of the pilot injections. After a thorough analysis of the quantities affecting the ignition delay, this quantity was modeled as a function of both a thermodynamic and a chemical-physical index. The comparison between the measured and modeled ignition delay shows an accuracy compatible with the requirements for control purposes (the average root mean squared error between the measured and estimated start of combustion is close to 1.3 deg), over a wide range of operating conditions. As a result, the presented approach proved to be appropriate for the development of a model-based feed-forward contribution for a closed-loop combustion control strategy

    Evaluasi Sistem Informasi Penjualan pada PT XYZ

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    The study aims to evaluate the sales information system of PT XYZ whether the system supports the company\u27s goals, as well as to determine the problem and control done by the company. Literature study and field studies through observation, interviews and checklists are implemented. The results of this evaluation are weaknesses in information systems presented on matrices of risk assessment and audit reports. The evaluation discovers the weaknesses of each control which are the potential risks and recommendation need. The controlimplemented by the company still needs to be improved further, particularly in the controls of input and output which are still weak
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