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We discuss a simple method for fabricating interference birefringent filters using common cellophane tape layers. Cellophane tape layers can be superimposed with different orientations to generate different spectral responses. We demonstrate this behavior with a portable spectrophotometer. This technique is a simple and inexpensive way of investigating the optical properties of birefringent filters.

The Occupational Health and Safety Management System is a fundamental tool that identifies, evaluates, and controls the risks and dangers to which they are exposed to workers in work environments. Also, it permits companies to develop improvement plans and activities in compliance with the country's government regulations, regardless of the size and economic activity of each one. In Bogotá, there is an association of waste pickers, constituted as a household public service company. They are mainly dedicated to promoting, integrating, organizing, facilitating, representing, and guiding waste pickers by trade to collect, classify, and dispose of usable solid waste. Given the activity they carry out, there is concern about the deterioration of the health conditions of the workers or, in many cases, the occurrence of work accidents, which entail different problems for the company. It is noteworthy that some risks to which the company's workers are exposed in the exercise of their work include: the risk of contamination, intoxication, infection, skin lesions, and deterioration of skin integrity due to the non-use of personal protection elements (PPE) and biohazard from contact with hazardous waste or residues. Based on the above, it is essential to establish management systems for the well-being and health of workers; therefore, this work focuses on the design of the Occupational Health and Safety Management System (OHSMS) based on ISO 45001: 2018. The system's adoption offers the necessary instruments to help identify, control, and mitigate the risk factors inherent in the work activity. Additionally, it is intended that workers can have safe workspaces with the promotion of good practices in favor of environmental and occupational care in the exercise of their work, avoiding penalties for non-compliance with this. [ABSTRACT FROM AUTHOR]

The high accident rates, occupational diseases, and occupational illnesses have brought significant concerns in the different business activities, therefore over the years, rules have been generated to regulate and control the risks and diseases that employees may be subject to during work activities. Thus, the ILO (International Labor Organization) has provided provisions and regulations on OHS issues, and Colombia has adhered to them as a member state. In this respect, many companies around the country are committed to ensuring employees' health and providing safety to them during the development of their activities. A clear example of the above is a company whose activity is the commercialization of pharmaceutical and medicinal products, cosmetics, and toiletries, which has currently positioned itself as one of the leaders in this sector. This company has been in business for more than 20 years and has more than 960 points of sale throughout the country. Thus, after an extensive review of the company's guidelines and directives, it became evident that there are shortcomings in the lack of an OHSMS. Although some of the country's OHS regulations are applied, the need to apply a standard like ISO 45001 is highlighted. The application of ISO 45001 helps companies minimize significant risks that cannot be overlooked and improve quality standards, giving employers and employees more confidence. This work focuses on designing the management system for occupational safety and health of a company marketing pharmaceutical products in one of its offices located in Bogota. For this purpose, the requirements of the international standard ISO 45001:2018 are considered, and its implementation is intended to make employees feel at ease and safer when working. It should be noted that, for the company, the design of the Occupational Health and Safety Management System (OHSMS) will facilitate risk management and reduce the likelihood of occupational illnesses and accidents to which employees may be exposed. Additionally, it is expected that with the system's design, the company can be directed towards increasing the performance and continuous improvement of the organization, and it may involve having an advantage over companies that do not yet comply with this standard. [ABSTRACT FROM AUTHOR]

Day by day, there is a growing trend and interest in introducing new ingredients and elements to create food to guarantee or achieve food safety and good health. With these creations, it is tried that the new foods satisfy needs at a nutritional level, mainly because of the benefits that they can offer for specific health conditions that some individuals of the population present, such as diabetes, coronary heart disease, and some cancers, among others. On the other hand, it is also tried with these new foods that can help to supply dietary preferences that, in one way or another, are associated with all those changes in consumption habits in communities. Changes are given by factors such as obesity or aging, and that in the end, changes are associated with needs, acquired behaviours, or people's conditions. Among the versatile products for incorporating new ingredients and generating new formulas are from the bakery activity. It is common on these products to find that vegan Cupcakes are offered (those that are made with only fruits and without any derived from animals such as milk or eggs) and sweet Cupcakes (made with sugar). In this work, the introduction of vegetarian and vegan cupcakes, made from ingredients such as spinach, carrots, tomatoes, corn, and mushrooms, is presented as an innovation. These cupcakes are characterized by low carbohydrate content and are ideal for maintaining low-fat, low-carb diets. During the work, preferences of a segment of the population between 25-40 years old are evaluated, who have health problems related to diabetes, and consider the cupcake proposal attractive. Additionally, characteristics of the formulated and developed product are presented. [ABSTRACT FROM AUTHOR]

The planet's pollution from greenhouse gases resulting from fossil energy sources' inefficient use, has made the scientific community reflect and has led it to search for new alternative and renewable energy sources to supply increasing energy needs. One of the sources that have had significant growth worldwide in the last decade is photovoltaic solar energy. However, one of the drawbacks with the use of photovoltaic technology is conversion efficiency. For this, alternatives are sought, such as the study of new materials with structures that facilitate the quantum photodetection of a given compound; minimize losses due to transient and harmonic in the regulation devices and inverters, and losses in the storage and transport of the energy generated. One proposal to increase the collection efficiency is solar tracking systems, making the panels remain approximately perpendicular to the direct light beam (direct radiation), from dawn to sunset. In this research work, three photovoltaic solar energy capture systems are compared using a simulation. The first case corresponds a fixed system in a horizontal position; the second case is a system fixed with an inclination of 10 degrees south latitude, and the third, a two-axis tracker. The information collected is taken in the municipality of Sibaté, the coordinates 4 ° 30 ' 09.5 " N, 74 ° 15 ' 20.2 " W in the Savanna of Bogotá. The purpose of this study is to use clean electrical energy to obtain bio-hydrogen using electrolysis. In the simulation, two periods, cloudy and clear, are determined based on a threshold taken experimentally in the panels and thus comparing the three systems. The results show that in clear periods the solar tracker has an energy conversion gain of 5 %. On the other hand, in cloudy periods, the three systems' panels showed similarity in the energy measurements captured. [ABSTRACT FROM AUTHOR]

The realization of PHA (Process Hazard Analysis) as an evaluation of all those elements that are part of management programs for safety in industrial processes that can generate an impact on the profitability of the company, is a matter to highlight. Given the above, industries need to identify the variations that occur concerning normal parameters in the process. During the development of the study, operational risks are analysed in the process of a dairy plant, located in Cundinamarca, Colombia. For this analysis, the HAZOP methodology is used, which will allow the identification of hazards, operability study, and mitigation of the risks related to the investigated process. For the analysis, the pasteurization and mixing stage as the subsystem was determined. In this operational stage, the node to study was the reactor. The different diagrams of the node for the analysis were established. The specifications at the equipment and instrumentation level were used. Previous information, plus the contributions regarding the operation of the plant by staff, the inputs are compiled for the development of the mentioned methodology. Once the deviations in the studied node were identified, the possible origins and effects of each deviation were determined. The measures and corrective actions necessary for improvements in the production process were proposed. [ABSTRACT FROM AUTHOR]

Many companies in the search for to make themselves known and increase visibility, which involves the transmission of confidence in the products offered, and in the execution of processes in a safe way, resort to the implementation of management systems. In this contribution, is proposed the design of the Occupational Health and Safety Management System for a company that manufactures and markets low voltage electrical panels. The main is to improve the working conditions of its employees and the productivity of the organization. All work carried out was supported both in ISO 45001: 2018 and in Colombian legislation. The actions will allow the growth of the company internally, will contribute to the development of logical processes, and in stages for improvement, continues having as a principle the PHVA cycle. It is essential to mention that, during the operational phase, tools such as preventive medicine, hygiene, and industrial safety programs were developed, as well as alternatives that involve verification of compliance with the established requirements of the standard, and thus achieve the results desired management system. Designed solutions were based, in analysis and development of identification of risks and hazards as the first instance, this was essential for the documentary design of the Management System, where it intends the standardization of the processes and the increase in the effectiveness in the company. [ABSTRACT FROM AUTHOR]

The problems caused by a large amount of waste produced every day become one of the main concerns of world nations. Then, a question is how various actions arise that seek a transformation in the habits and mentalities. One way to contribute to this cause is to change the sources of polluting energy for sustainable energy, such as hydrogen based. It has a high energy efficiency, and its combustion does not generate polluting emissions. Likewise, as a source for the generation of clean energy, residual biomass is used, which turns out to be a feasible option since its availability is abundant. In the cocoa industry, one of the residues that stands out for its quantity is the cocoa mucilage. This residue can act as a substrate to provide biogas, and that contains high levels of sugars, fibers, proteins, and nutrients. However, in this study, the possibility of producing hydrogen from cocoa mucilage is evaluated by dark fermentation processes. The evaluation is carried out on a laboratory scale, by tests in batch reactors made of 250 ml amber glass and with a 220 ml headspace. The temperatures evaluated during the experiment were 35 °C (mesophilic) and 55 C (thermophilic). The organic loads evaluated during the process were 4, 8, and 12 grams of volatile solids per liter (gVS / L), respectively. The experimental testing duration was subject to the presence of methane in the gas produced. For determining the methane presence, a portable analyzer was used. The gas determination was done daily. The evidence of the reaction rate in the tests at 55 ° C is higher than at 35 ° C, and the presence of methane at thermophilic conditions occurred at five days, while the mesophilic conditions occurred at 23 days. It is found that, for tests at two temperatures, the best results are detected when the organic load is 12 gVS / L, and the maximum hydrogen production (703 mL H2) is reached when the temperature is 35 ° C. The maximum production suggests that under mesophilic conditions the process can be maintained in hydrolysis for longer times. [ABSTRACT FROM AUTHOR]

The treatment of residual biomass through the dark fermentation (DF) process is presented as a sustainable alternative, where bio-hydrogen is produced, which has a high energy potential, and bio-based sub-products. Consequently, this work aimed to determine the maximum organic load for the production of bio-hydrogen, from residual biomass available in Colombia. An experimental design was constructed to determine the biochemical hydrogen potential (BHP) of mixtures composed of three substrates: pig manure (PM), cocoa mucilage (CCM), and coffee mucilage (CFM). The design managed two independent variables, the organic load (10 gVS/l, 20 gVS/l, 30 gVS/l, 40 g VS/l, and 50 gVS/l), which were determined according to the physicochemical characterization of the substrates, and the S/X evaluated on two levels 1:1 and 1:2. The experiments were carried under mesophilic conditions (±35°C), a C/N ratio of 35, and a pH of 5.5 was fixed. As a result, five mixtures were evaluated, plus five targets. The reactors were erlenmeyers of 250mL, hermetically sealed, heated, and stirred in a hot plate. The tests were allowed to run until the detection of CH4; daily monitoring with a Biogas 5000® portable gas analyser did this. Following the determination of the physicochemical characteristics of the effluent, total solids (TS), volatile solids (VS), proteins, and chemical oxygen demand COD were analysed for each of the reactors. The results show that the organic load of 10gSV/L and the S/X of 1 has the highest production rate with 232 mL of H2, with a production of volatile fatty acids (VFA) of 4040mg COD/L, and a VS removal percentage of 84%. The removal of VS and the VFA allows suggesting secondary processes associated with bio-refinery schemes, for a more significant elimination of volatile solids and the obtaining of other value-added by-products. [ABSTRACT FROM AUTHOR]

Electrodic surfaces of natural chalcopyrite and natural pyrite minerals are studied by cyclic voltammetry, electrochemical impedance spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy including microanalysis. At high oxidation states, both minerals showed a pseudoinductive loop in the equivalent circuit, which was due to the active electrodissolution of the minerals, which takes place through a surface film previously formed.

In the following work a new mode of operation is presented, as a continuation of the research developed on the elaboration of an electromagnetic model for the determination of the speed of photonic absorption in a solar collector in V (V - collector) (Ramos et al. 2017). The electromagnetic characteristics of the fluid in the suspension will be studied, such as electric permittivity, magnetic permeability, electrical conductivity and frequency of incident light. Likewise, the time variable is included as the innovation in the model to obtain the factors of the phase and the attenuation of the electromagnetic wave that penetrates the suspending medium and the photocatalytic process. For the model, an opto-geometric analysis of the V collector was used, which was studied and contrasted with the literature (Bandala et al. 2004). [ABSTRACT FROM AUTHOR]